FN Thomson Reuters Web of Science™ VR 1.0 PT J AU COFFEY, MW CLEM, JR AF COFFEY, MW CLEM, JR TI MAGNETIC-FIELD DEPENDENCE OF RF SURFACE IMPEDANCE SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID RESISTANCE; Y1BA2CU3OY; TEMPERATURE; SUPERCONDUCTORS; YBA2CU3O7-X; FREQUENCY AB The surface impedance, Z(s), is calculated for type-II superconductors subjected to a static magnetic field and small-amplitude microwave radiation. A complex penetration depth is calculated by using a model of vortex dynamics including a linear pinning restoring force and a viscous drag force. The static magnetic field dependence of the surface resistance R(s) and surface reactance X(s) is found by examining the dependence of the complex penetration depth on the length scales for low-field penetration, pinning penetration, and flux-flow penetration. In turn, from R(s), the static magnetic field dependence of the rate of energy dissipation is found. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP COFFEY, MW (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 14 TC 40 Z9 40 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2136 EP 2139 DI 10.1109/20.133634 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300118 ER PT J AU HAWSEY, RA KAHL, WK SCHWENTERLY, SW BAILEY, JM SOHNS, CW LUTON, JN MCCONNELL, BW CAMPBELL, VW AF HAWSEY, RA KAHL, WK SCHWENTERLY, SW BAILEY, JM SOHNS, CW LUTON, JN MCCONNELL, BW CAMPBELL, VW TI ANALYSIS AND PERFORMANCE OF AN AXIAL-GAP SUPERCONDUCTING MOTOR SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB The performance of a variable-speed ac, superconducting motor has been evaluated. A novel axial-gap geometry was chosen for four-pole, 1800-rpm operation, using a superconducting stator and normal armature. The pool-boiling cryostat contains four solenoidal field windings of filamentary niobium-titanium conductor and has a maximum field of 7 T and an air-gap field of 2 to 3 T. The armature windings are formed from copper Litz wire and are arranged in 48 radial slots. The wire inside diameter and outside diameter are 17.18 and 69.24 cm, respectively. The armature is driven by three-phase power supplied via slip rings and an adjustable-speed drive. The maximum design power is 100 hp, which can be doubled by using two armatures. Motor-performance data as a function of speed and air-gap flux density are presented for initial low-power tests with a drive capable of delivering 60 A per phase to the armature. RP HAWSEY, RA (reprint author), OAK RIDGE NATL LAB,POB 2003,OAK RIDGE,TN 37831, USA. NR 3 TC 1 Z9 1 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2252 EP 2255 DI 10.1109/20.133664 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300146 ER PT J AU GREEN, MA AF GREEN, MA TI A COMPARISON OF ASTROMAG COILS MADE WITH ALUMINUM AND COPPER BASED SUPERCONDUCTOR SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB The use of aluminum matrix superconductor in the coils for the ASTROMAG magnet will increase the integrated field for doing particle astrophysics in space as compared to equal mass coils made with copper matrix superconductor. The increased ability to detect charged particles can be achieved without decreasing the current margin of the superconductor in the coils. The use of a low resistivity aluminum matrix conductor increases the energy need to initiate a quench by two orders of magnitude. The current decay time constant during a quench is substantially increased. As a result, the quench energy dumped into the helium tank is reduced (The ASTROMAG coils are thermally decoupled from the helium tank.), and the forces on the shields and shells due to eddy currents will be lower. This paper also describes the problems associated with the use of aluminum matrix superconductor in the coils. RP GREEN, MA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 8 TC 0 Z9 0 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2260 EP 2263 DI 10.1109/20.133667 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300148 ER PT J AU SCHOENUNG, SM MEIER, WR HASSENZAHL, WV AF SCHOENUNG, SM MEIER, WR HASSENZAHL, WV TI A COMPARISON OF LARGE-SCALE TOROIDAL AND SOLENOIDAL SMES SYSTEMS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID ENERGY-STORAGE AB Over the past two decades, studies of large-scale superconducting magnetic energy storage (SMES) for commercial utility applications have focused on solenoidal configurations. This selection has typically been justified on the basis of cost. A toroidal configuration would have a much less extensive external magnetic field, which might be a desirable feature for siting a SMES unit where land is limited. This paper reviews the characteristics of large-scale toroidal and solenoidal coils (> 10 MWh, or 36 GJ) to establish a basis for quantitative estimates of the material requirements for these two SMES systems and compares the size dependence, scaling features, and the estimated costs for major material components. Results show that requirements for major materials in the toroid exceed those for the solenoid by factors from 2 to more than 5, depending on size and assumptions. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP SCHOENUNG, SM (reprint author), WJ SCHAFER ASSOC INC,6140 STONERIDGE MALL RD,SUITE 385,PLEASANTON,CA 94566, USA. NR 12 TC 21 Z9 21 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2324 EP 2328 DI 10.1109/20.133683 PN 3 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300164 ER PT J AU HEIM, JR PARKER, JM AF HEIM, JR PARKER, JM TI A CONCEPTUAL DESIGN OF THE INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR CENTRAL SOLENOID SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB Conceptual design of the International Thermonuclear Experimental Reactor (ITER) superconducting magnet system is nearing completion by the ITER Design Team, and one of the Central Solenoid (CS) designs is presented. The CS part of this magnet system will be a vertical stack of eight modules, approximately 16 m high, each having approximate dimensions of: 4.1-m o.d., 2.8-m i.d., 1.9-m h. The peak field at the bore is approximately 13.5 T. Cable-in-conduit conductor with Nb3Sn composite wire will be used to wind the coils. The overall coil fabrication will use the insulate-wind-react-impregnate method. Coil modules will be fabricated using double-pancake coils with all splice joints located in the low-field region on the outside of the coils. All coils will be structurally graded with high-strength steel reinforcement which is co-wound with the conductor. We describe details of the CS coil design and analysis. RP HEIM, JR (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 5511,L-643,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2365 EP 2368 DI 10.1109/20.133693 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300174 ER PT J AU GHOSH, AK SUENAGA, M AF GHOSH, AK SUENAGA, M TI MAGNETIZATION AND CRITICAL CURRENTS OF TIN-CORE MULTIFILAMENTARY NB3SN CONDUCTORS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID CABLE AB This paper presents critical current and magnetization data for some multifilamentary Nb3Sn wires that have been produced by the internal-tin method. A comparison of magnetization and transport critical current measurements show that filament bridging during heat treatment is a common occurrence leading to effective filament diameters that are sometimes an order of magnitude larger than the geometrical filament size. At present, J(c)'s (in the non-copper region) greater than 1300 A/mm2 at 10T have been achieved in some conductors, which also exhibit high losses. Low losses have only been seen in conductors with a high local ratio of copper to niobium. Also the use of (Nb-1%Ti) alloy instead of pure Nb helps to reduce low field loss and increase high field J(c). Measurements of the temperature dependence of hysteretic loss to 5T indicate that loss decreases linearly with increasing temperature. RP GHOSH, AK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 20 TC 12 Z9 12 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2407 EP 2410 DI 10.1109/20.133704 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300185 ER PT J AU WEINBERGER, BR LYNDS, L VANVALZAH, J EATON, HE HULL, JR MULCAHY, TM BASINGER, SA AF WEINBERGER, BR LYNDS, L VANVALZAH, J EATON, HE HULL, JR MULCAHY, TM BASINGER, SA TI CHARACTERIZATION OF COMPOSITE HIGH-TEMPERATURE SUPERCONDUCTORS FOR MAGNETIC BEARING APPLICATIONS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID PENETRATION DEPTH AB A study of high temperature superconductor composites for use in magnetic bearings applications is presented. Fabrication and characterization techniques are described. Magnetometry and mechanical force measurements are correlated with a particular emphasis on the role of superconductor particle size. Results are discussed in terms of fundamental limits of Meissner effect levitation. C1 ARGONNE NATL LAB,DIV MAT & COMPONENT TECHNOL,ARGONNE,IL 60439. RP WEINBERGER, BR (reprint author), UNITED TECHNOL RES CTR,E HARTFORD,CT 06108, USA. NR 21 TC 22 Z9 22 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2415 EP 2422 DI 10.1109/20.133706 PN 3 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300187 ER PT J AU LI, Q XI, XX WU, XD INAM, A VADLAMANNATI, S RAMESH, R SHWARTZ, S HWANG, DM WILKENS, B MARTINEZ, JA MCLEAN, WL VENKATESAN, T AF LI, Q XI, XX WU, XD INAM, A VADLAMANNATI, S RAMESH, R SHWARTZ, S HWANG, DM WILKENS, B MARTINEZ, JA MCLEAN, WL VENKATESAN, T TI SUPERCONDUCTIVITY IN YBA2CU3O7/PRBA2CU3O7 SUPERLATTICES SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID TRANSITION; CRYSTALS; FILMS AB High quality YBa2Cu3O7/PrBa2Cu3O7 superlattices with desired thickness of each component were fabricated by laser deposition. Superconductivity was studied by varying both YBa2Cu3O7 and PrBa2Cu3O7 layer thicknesses. The results indicated that an isolated single unit cell YBa2Cu3O7 layer (nominal thickness of 12 angstrom) is superconducting. The increase of T(c) from the lower value of a single unit cell layer to 90 K in thick films and the enhancement of T(c) for a given thickness of YBa2Cu3O7 when the PrBa2Cu3O7 layers decreased to less than approximately 30 angstrom could be attributed to the interlayer coupling effect. Superconducting transitions of superlattices in applied magnetic fields were studied. The interlayer coupling effect on vortices can be seen by comparing the transition curves in high magnetic fields of thick film, ultrathin film and superlattice. For the samples with very thin YBa2Cu3O7 layers, similar results to vortex-antivortex pair phase transition was observed by measuring the temperature dependence of resistance, magnetoresistance, and I-V curves, indicating a strong two dimensional behavior in very thin YBa2Cu3O7 films. C1 BELLCORE,RED BANK,NJ 07701. UNIV CALIF LOS ALAMOS SCI LAB,ERDC,LOS ALAMOS,NM 87545. RP LI, Q (reprint author), RUTGERS STATE UNIV,DEPT PHYS,PISCATAWAY,NJ 08854, USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 14 TC 4 Z9 4 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2472 EP 2475 DI 10.1109/20.133988 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300201 ER PT J AU NAHUM, M RICHARDS, PL AF NAHUM, M RICHARDS, PL TI DESIGN ANALYSIS OF A NOVEL LOW-TEMPERATURE BOLOMETER SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB We propose a novel antenna-coupled superconducting bolometer which makes use of the thermal boundary resistance available at low temperatures. The radiation is collected by a planar self-complementary antenna and thermalized in a small thin film resistor. The resulting temperature rise is detected by a transition edge thermometer which can be (but need not be) a separate film. All components are deposited directly on a substrate so that arrays can be conveniently produced by conventional lithographic techniques. The active area of the bolometer is thermally decoupled by its small size and by the thermal resistance of the boundaries with the substrate and the antenna terminals. Design calculations based on a 2 x 2-mu-m square film of a superconductor with T(c) almost-equal-to 0.1 K give an NEP almost-equal-to 10(-18) WHz-1/2, time constant almost-equal-to 10(-6) s and responsivities up to almost-equal-to 10(9) V/W. These specifications meet the requirements for NASA's Space Infrared Telescope Facility and Sub-Millimeter Moderate Mission. Useful applications also exist at He-3 and He-4 temperatures. The calculated NEP scales as T5/2. Materials, architectures, and readout schemes will be discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP NAHUM, M (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 22 TC 16 Z9 16 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2484 EP 2487 DI 10.1109/20.133722 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300204 ER PT J AU RADOUSKY, HB GLASS, RS BACK, D CHIN, AH FLUSS, MJ LIU, JZ MOSLY, WD KLAVINS, P SHELTON, RN AF RADOUSKY, HB GLASS, RS BACK, D CHIN, AH FLUSS, MJ LIU, JZ MOSLY, WD KLAVINS, P SHELTON, RN TI PROCESSING PARAMETERS AND KINETICS OF BROMINATION AND CHLORINATION IN THE YBA2CU3O6+X SYSTEM SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB The introduction of halogens such as Cl2,Br2 can restore 90 K superconductivity to oxygen deficient YBa2Cu3O6+x. This is potentially important for applications to thin film devices due to the low processing temperatures required relative to reprocessing with oxygen. Low temperature 260-degrees-C and short time (> 5 minute) bromination has been shown1 to convert initially insulating YBa2Cu3O6.2 powder to a high temperature superconductor with properties similar to the standard O7 material. This process has now been extended to single crystals as well, but with somewhat different processing parameters. Thermal gravimetric analysis (TGA) coupled with mass spectrometry indicates that the Br becomes strongly bonded, with no release of Br observed in taking powder samples to 1000-degrees-C in flowing forming gas (2%H2/98%N2). The reaction has also been found to be highly exothermic for both Br and Cl treatments, which is consistent with the strong bonding of the bromine discussed above. C1 UNIV CALIF DAVIS,DAVIS,CA 95616. RP RADOUSKY, HB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 6 TC 8 Z9 8 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2512 EP 2514 DI 10.1109/20.133729 PN 3 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY653 UT WOS:A1991EY65300211 ER PT J AU WELLSTOOD, FC KINGSTON, JJ FERRARI, MJ CLARKE, J AF WELLSTOOD, FC KINGSTON, JJ FERRARI, MJ CLARKE, J TI THIN-FILM FLUX TRANSFORMERS OF YBA2CU3O7-X SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID NOISE AB Using a three-layer in situ laser deposition process, we have constructed superconducting thin-film flux transformers of YBa2Cu3O7-x (YBCO). The transformers are designed for efficient coupling to a planar thin-film dc SQUID, have 0.7cm2 magnetic field pickup areas, and 10-turn input coils. When coupled to a low transition temperature (T(c)) SQUID, the resulting hybrid magnetometer exhibits excess low frequency flux noise which arises in the transformer. This noise depends on the geometry of the flux transformer, and the observed behavior agrees with model calculations of the expected contribution from flux motion in the YBCO. The hybrid magnetometer attains a magnetic field sensitivity of about 0.9pTHz-1/2 at 1Hz with the transformer at 60K; the rms noise decreases as 1/f1/2 up to a frequency f almost-equal-to 1kHz. We believe that the sensitivity is high enough for use, for example, in magnetocardiography. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94720. RP WELLSTOOD, FC (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Joint Quantum Institute, NIST/UMD/H-4494-2011 NR 16 TC 7 Z9 7 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2569 EP 2572 DI 10.1109/20.133740 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400010 ER PT J AU LACOE, RC HURRELL, JP SPRINGER, K RAISTRICK, ID HU, R BURCH, JF SIMON, RS AF LACOE, RC HURRELL, JP SPRINGER, K RAISTRICK, ID HU, R BURCH, JF SIMON, RS TI LOW-FREQUENCY 1/F NOISE MEASUREMENTS IN YBA2CU3O7 THIN-FILMS AND THE IMPLICATIONS FOR HTS IR DETECTORS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID RESISTANCE FLUCTUATIONS; OPTICAL-RESPONSE; 1-F NOISE; SUPERCONDUCTORS; TEMPERATURE AB The low frequency noise voltage fluctuations were measured on c-axis textured thin films of YBa2Cu3O7 on (100) SrTiO3 and on mixed a- and c- axis textured thin films of YBa2Cu3O7 on (100) LaAlO3. In all cases, the power spectral density S(v)(f) approximately V2/f-alpha, where V is the average dc voltage across the film. Measurements on structures of different surface areas indicates S(v)(f) is inversely proportional to the film surface area. From room temperature to above the superconducting transition temperature, S(v)(f)/V2 approximately T2, while near the transition S(v)(f)/V2 levels off before increasing sharply as the resistance goes to zero. The linear dependence of S(v)1/2(f) on the bias current suggests that the noise arises from resistance fluctuations. The resistance fluctuations are interpreted as arising from two different mechanisms; a "weakly" temperature dependent contribution which is dominant above the superconducting transition and a "strongly" temperature dependent contribution which dominates at the transition. The implications of these measurements on the potential utility of HTS IR detectors will be discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. TRW CO INC,SPACE & TECHNOL GRP,REDONDO BEACH,CA 90278. RP LACOE, RC (reprint author), AEROSPACE CORP,EL SEGUNDO,CA 90245, USA. NR 15 TC 19 Z9 19 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2832 EP 2835 DI 10.1109/20.133991 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400069 ER PT J AU LI, Q FINNEMORE, DK AF LI, Q FINNEMORE, DK TI ABRIKOSOV VORTEX MEMORY BASED ON A SINGLE VORTEX SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID SUPERCONDUCTING VORTEX AB An Abrikosov vortex memory device based on a cross strip superconducting-normal-insulating-superconducting (SNIS) Josephson junction has been developed to investigate the feasibility of using the motion of a single vortex to store information and perform logic. The write operation is performed by moving a single vortex from one pinning site to another using a current in one leg of the cross strip junction. The read operation is performed by measuring the Josephson voltage at a fixed bias Josephson current. For these PbBi-Al2O3-Al-Pb SINS junctions, the Josephson voltage depends on the vortex position because the vortex distorts the Fraunhofer diffraction pattern in a predictable way. The device is superior to earlier superconductor-normal-superconductor (SNS) devices in that the junction voltages are millivolts and can be read with rather simple electronics. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP LI, Q (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 4 TC 9 Z9 9 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 2913 EP 2915 DI 10.1109/20.133819 PN 4 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400090 ER PT J AU VERGHESE, S RICHARDS, PL CHAR, K SACHTJEN, SA AF VERGHESE, S RICHARDS, PL CHAR, K SACHTJEN, SA TI FABRICATION OF AN INFRARED BOLOMETER WITH A HIGH-TC SUPERCONDUCTING THERMOMETER SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB A sensitive high T(c) superconducting bolometer has been fabricated on a 20-mu-m thick sapphire substrate with a YBCO thin film transition edge thermometer. Optical measurements with a He-Ne laser gave a noise equivalent power of 2.4.10(-11) W/Hz1/2 at 10 Hz and a responsivity of 17 V/W in good agreement with electrical bolometer measurements. Gold black smoke was then deposited on the back side of the assembled bolometer as an absorber. Spectral measurements on a fourier transform spectrometer show that the bolometer has useful sensitivity from visible wavelengths to beyond approximately 100mu-m. This performance is clearly superior to that of a commercial room temperature pyroelectric detector. Some improvement appears possible. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. CONDUCTUS INC,SUNNYVALE,CA 94086. RP VERGHESE, S (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 10 TC 53 Z9 53 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3077 EP 3080 DI 10.1109/20.133862 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400133 ER PT J AU NAHUM, M HU, Q RICHARDS, PL SACHTJEN, SA NEWMAN, N COLE, BF AF NAHUM, M HU, Q RICHARDS, PL SACHTJEN, SA NEWMAN, N COLE, BF TI FABRICATION AND MEASUREMENT OF HIGH-TC SUPERCONDUCTING MICROBOLOMETERS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB We have fabricated and measured the performance of antenna-coupled microbolomers based on the resistive transition of a high T(c) superconducting film for use as detectors of far-infrared and millimeter waves. A planar lithographed antenna (log-periodic or log-spiral) is used to couple the radiation to a thin YBCO film with dimensions (almost-equal-to6 x 13 mu-m2) which are much smaller than the wavelength to be measured. This film acts both as the resistor to thermalize the RF currents and as a transition edge thermometer to measure the resulting temperature rise. Because of its small size, both the thermal conductance from the film into the bulk of the substrate and the heat capacity of the thermally active region are small. Consequently, the microbolometer has low noise, fast response and a high voltage responsivity. We have measured a phonon limited electrical NEP of 4.5 x 10(-12) WHz-1/2 at 10 kHz modulation frequency and a responsivity of 478 V/W at a bias of 550 mu-A. Measurements of the optical efficiency are in progress and will be discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. CONDUCTUS INC,SUNNYVALE,CA 94086. RP NAHUM, M (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Newman, Nathan/E-1466-2011 OI Newman, Nathan/0000-0003-2819-9616 NR 11 TC 47 Z9 47 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3081 EP 3084 DI 10.1109/20.133863 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400134 ER PT J AU MIKLICH, AH WELLSTOOD, FC KINGSTON, JJ CLARKE, J COLCLOUGH, MS CARDONA, AH BOURNE, LC OLSON, WL EDDY, MM AF MIKLICH, AH WELLSTOOD, FC KINGSTON, JJ CLARKE, J COLCLOUGH, MS CARDONA, AH BOURNE, LC OLSON, WL EDDY, MM TI HIGH-TC THIN-FILM MAGNETOMETER SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID DC SQUIDS AB We have constructed and tested high-T(C) magnetometers by coupling a high-T(C) thin-film Superconducting QUantum Interference Device (SQUID) to two different high-T(C) thin-film flux transformers. The SQUID was made from Tl2CaBa2Cu2O8+y films grown on MgO, with junctions consisting of native grain boundaries. The flux transformers were made from YBa2Cu3O7-x, and each had 10-turn input coils and a single-turn pickup loop. The first transformer, which was patterned with a combination of shadow masks and photolithography, yielded a magnetic field gain of about -7.5, functioned up to 79 K, and gave a magnetic field sensitivity B(N) (10 Hz) almost-equal-to 3.1 pT Hz-1/2 at 38 K. The second transformer, which was patterned entirely by photolithography, yielded a gain of about -8.7, functioned up to 25 K, and had a sensitivity B(N) (10 Hz) almost-equal-to 3.5 pT Hz-1/2 at 4.2 K. In both cases, the limiting noise arose in the SQUID. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94720. SUPERCONDUCTOR TECHNOL INC,SANTA BARBARA,CA 93111. RP MIKLICH, AH (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Joint Quantum Institute, NIST/UMD/H-4494-2011 NR 14 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3219 EP 3222 DI 10.1109/20.133896 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400168 ER PT J AU MARTENS, JS GINLEY, DS BEYER, JB NORDMAN, JE HOHENWARTER, GKG AF MARTENS, JS GINLEY, DS BEYER, JB NORDMAN, JE HOHENWARTER, GKG TI A JOSEPHSON JUNCTION TO FET HIGH-SPEED LINE DRIVER MADE OF TLCABACUO SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID S-PARAMETER MEASUREMENTS; TC MATERIALS; DEVICES AB We have used a Tl-Ca-Ba-Cu-O superconducting flux flow transistor (SFFT) as an active impedance converter between Josephson and FET circuitry. The input of the flux flow device is a control line of low impedance that can be driven by a tunnel junction. The output is the signal across the SFFT which is made of a parallel array of weak links. The output impedance is typically greater than 5-OMEGA with a maximum voltage swing of over 100 mV into a 50-OMEGA system. The switching of an all-Nb junction induced a 90 mV voltage swing at the FET input and over 200 mV at the FET output. The line driver can operate anywhere between 4.2K and 85K with minor changes in speed (+/- 5 ps) and output level (+/- 10 mV). The switching time measured was about 100 ps and was fixture limited. C1 UNIV WISCONSIN,DEPT ELECT & COMP ENGN,MADISON,WI 53706. HYPRES INC,ELMSFORD,NY 10523. RP MARTENS, JS (reprint author), SANDIA NATL LABS,ORG 144,ALBUQUERQUE,NM 87185, USA. NR 13 TC 21 Z9 21 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3284 EP 3288 DI 10.1109/20.133914 PN 4 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400184 ER PT J AU HOHENWARTER, GKG MARTENS, JS THOMPSON, JH BEYER, JB NORDMAN, JE GINLEY, DS AF HOHENWARTER, GKG MARTENS, JS THOMPSON, JH BEYER, JB NORDMAN, JE GINLEY, DS TI CHARACTERISTICS OF SUPERCONDUCTING FLUX-FLOW TRANSISTORS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO AB The operational characteristics and physics of three superconducting thin-film based transistor structures are compared. The devices are based on the motion of quantized vortices, either Josephson fluxons in a long tunnel junction or Abrikosov fluxons in a superconducting film. The transistor amplification mechanism, in all three cases, is accomplished by controlling magnetic field at the boundaries of the structure. This paper provides an overview of present understanding of device mechanisms and of measured characteristics, including voltampere relations and small and large signal circuit parameters. Demonstrated applications and anticipated limitations are discussed. C1 UNIV WISCONSIN,DEPT ELECT & COMP ENGN,MADISON,WI 53706. SANDIA NATL LABS,ORG 1144,ALBUQUERQUE,NM 87185. RP HOHENWARTER, GKG (reprint author), HYPRES INC,175 CLEARBROOK RD,ELMSFORD,NY 10523, USA. NR 9 TC 17 Z9 17 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3297 EP 3300 DI 10.1109/20.133917 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400187 ER PT J AU HANSEN, JB HOLST, T WELLSTOOD, FC CLARKE, J AF HANSEN, JB HOLST, T WELLSTOOD, FC CLARKE, J TI LOW-FREQUENCY NOISE IN RESONANT JOSEPHSON SOLITON OSCILLATORS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID TRANSMISSION-LINE; DC SQUIDS; JUNCTIONS; PROPAGATION AB The noise in the resonant soliton mode of long and narrow Josephson tunnel junctions (Josephson Transmission Lines, JTLs) has been measured in the frequency range from 0.1 Hz to 25 KHz by means of a dc SQUID. To within a factor of 2 the measured white noise was found to be equal to the Nyquist voltage noise in a resistance equal to the dynamic resistance R(D) of the current-voltage characteristic at the bias point. In contrast, measurements of the linewidth of the microwave radiation from the same JTL showed that the spectral density of the underlying noise voltage scaled as R(D)2/R(S) where R(S) is the static resistance. The origin of the different behavior is not known. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. TECH UNIV DENMARK,MIDIT,PHYS LAB 1,DK-2800 LYNGBY,DENMARK. RP HANSEN, JB (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 14 TC 0 Z9 0 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3343 EP 3346 DI 10.1109/20.133928 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400198 ER PT J AU MEARS, CA HU, Q RICHARDS, PL WORSHAM, AH PROBER, DE RAISANEN, AV AF MEARS, CA HU, Q RICHARDS, PL WORSHAM, AH PROBER, DE RAISANEN, AV TI QUANTUM LIMITED QUASI-PARTICLE MIXERS AT 100 GHZ SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID SIS MIXERS; NOISE; MODEL AB We have made accurate measurements of the noise and gain of superconducting-insulating-superconducting (SIS) mixers employing small area (1-mu-m2) Ta/Ta2O5/Pb0.9Bi0.1 tunnel junctions. We have measured an added mixer noise of 0.61 +/- 0.31 quanta at 95.0 GHz, which is within 25 percent of the quantum limit of 0.5 quanta. We have carried out a detailed comparison between theoretical predictions of the quantum theory of mixing and experimentally measured noise and gain. We used the shapes of I-V curves pumped at the upper and lower sideband frequencies to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. YALE UNIV,DEPT APPL PHYS,NEW HAVEN,CT 06520. HELSINKI UNIV TECHNOL,RADIO LAB,SF-02150 ESPOO 15,FINLAND. RP MEARS, CA (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Raisanen, Antti/G-2405-2013 NR 21 TC 12 Z9 12 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3363 EP 3369 DI 10.1109/20.133934 PN 4 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400203 ER PT J AU MEARS, CA HU, Q RICHARDS, PL AF MEARS, CA HU, Q RICHARDS, PL TI THE EFFECT OF THE QUANTUM SUSCEPTANCE ON THE GAIN OF SUPERCONDUCTING QUASI-PARTICLE MIXERS SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1990 CONF ON APPLIED SUPERCONDUCTIVITY CY SEP 24-28, 1990 CL SNOWMASS, CO ID SIS MIXERS AB A detailed analysis of the effects of the quantum susceptance on the performance of superconductor-insulator-superconductor (SIS) mixers is performed. We find that the principal effects of the quantum susceptance are to change the dc bias at which optimum coupling of the signal to the mixer occurs, and to change the output admittance at the IF frequency, thus changing the available gain. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP MEARS, CA (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 13 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1991 VL 27 IS 2 BP 3384 EP 3387 DI 10.1109/20.133938 PN 4 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA EY654 UT WOS:A1991EY65400207 ER PT J AU SEGEV, A AF SEGEV, A TI STRATEGIES FOR DISTRIBUTED QUERY OPTIMIZATION SO INFORMATION SCIENCES LA English DT Article ID DATABASE-SYSTEMS; ALGORITHMS; JOIN C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT COMP SCI RES & DEV,DIV INFORMAT & COMP SCI,BERKELEY,CA 94720. RP SEGEV, A (reprint author), UNIV CALIF BERKELEY,SCH BUSINESS ADM,BERKELEY,CA 94720, USA. NR 42 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0020-0255 J9 INFORM SCIENCES JI Inf. Sci. PD MAR PY 1991 VL 54 IS 1-2 BP 67 EP 88 DI 10.1016/0020-0255(91)90045-V PG 22 WC Computer Science, Information Systems SC Computer Science GA EJ716 UT WOS:A1991EJ71600004 ER PT J AU CHAPPIDI, PR UNAL, C PASAMEHMETOGLU, KO NELSON, RA AF CHAPPIDI, PR UNAL, C PASAMEHMETOGLU, KO NELSON, RA TI ON THE RELATIONSHIP BETWEEN THE MACROLAYER THICKNESS AND THE VAPOR-STEM DIAMETER IN THE HIGH-HEAT-FLUX, POOL NUCLEATE BOILING REGION SO INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER LA English DT Article AB The authors consider the high-heat-flux, pool nucleate boiling region of a horizontal surface and propose a theoretical basis for estimating the constant of proportionality between the mean macrolayer thickness and the mean vapor-stem diameter at critical heat flux. This constant is found to be of the same order of magnitude (-10% difference) as that suggested by Gaertner [5]. While Gaertner's estimate is based on photographic evidence, the current approach uses a theoretical basis together with experimental data. RP CHAPPIDI, PR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV NUCL TECHNOL & ENGN,ENGN & SAFETY ANAL GRP,MAIL STOP K557,LOS ALAMOS,NM 87545, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0735-1933 J9 INT COMMUN HEAT MASS JI Int. Commun. Heat Mass Transf. PD MAR-APR PY 1991 VL 18 IS 2 BP 195 EP 205 DI 10.1016/0735-1933(91)90044-5 PG 11 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA FC519 UT WOS:A1991FC51900004 ER PT J AU Stewart, HB Thompson, JMT Lansbury, AN Ueda, Y AF Stewart, H. B. Thompson, J. M. T. Lansbury, A. N. Ueda, Y. TI GENERIC PATTERNS OF BIFURCATION GOVERNING ESCAPE FROM POTENTIAL WELLS SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article AB Extensive numerical simulations have established the generic character of patterns of bifurcation governing the escape of a forced oscillator across a smooth potential barrier and the close relation with the familiar nonlinear resonance within a potential well. Subtle but significant differences are found, depending on whether the damping is high or low, and the differences are related to the problem of experimentally determining the optimal escape condition. C1 [Stewart, H. B.] Brookhaven Natl Lab, Mat Sci Grp, Upton, NY 11973 USA. [Thompson, J. M. T.; Lansbury, A. N.] Univ Coll London, Dept Civil Engn, London, England. [Ueda, Y.] Kyoto Univ, Dept Elect Engn, Kyoto 606, Japan. RP Stewart, HB (reprint author), Brookhaven Natl Lab, Mat Sci Grp, Upton, NY 11973 USA. NR 4 TC 7 Z9 7 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-1274 EI 1793-6551 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD MAR PY 1991 VL 1 IS 1 BP 265 EP 267 DI 10.1142/S0218127491000191 PG 3 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA V44LK UT WOS:000209750300019 ER PT J AU Seidel, DB Kiefer, ML Coats, RS Pointon, TD Quintenz, JP Johnson, WA AF Seidel, D. B. Kiefer, M. L. Coats, R. S. Pointon, T. D. Quintenz, J. P. Johnson, W. A. TI The 3-D, Electromagnetic, Particle-In-Cell Code, QUICKSILVER SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article C1 [Seidel, D. B.; Kiefer, M. L.; Coats, R. S.; Pointon, T. D.; Quintenz, J. P.; Johnson, W. A.] Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Seidel, DB (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. FU U.S. Department of Energy [DE-AC04-76DP00789] FX This work was supported by the U.S. Department of Energy under Contract No. DE-AC04-76DP00789. NR 8 TC 0 Z9 0 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 MAR PY 1991 VL 2 IS 1 BP 475 EP 482 DI 10.1142/S012918319100072X PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA V33NI UT WOS:000209025100072 ER PT J AU STRICKLER, SJ CORMIER, RA CONNOLLY, JS AF STRICKLER, SJ CORMIER, RA CONNOLLY, JS TI EXCITON INTERACTIONS IN THE SPECTRUM OF A DINAPHTHONORBORNADIENE SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article ID TRANSITIONS AB The near-ultraviolet spectrum of a dinaphthonorbornadiene is reported and is interpreted using simple exciton theory that treats this molecule as a dimer of naphthalene. It shows examples of weak, intermediate, and strong coupling for the interaction of the three observed bands of napthalene. C1 METROPOLITAN STATE COLL,DEPT CHEM,DENVER,CO 80204. SOLAR ENERGY RES INST,PHOTOCONVERS RES BRANCH,GOLDEN,CO 80401. RP STRICKLER, SJ (reprint author), UNIV COLORADO,DEPT CHEM,BOULDER,CO 80309, USA. NR 17 TC 7 Z9 7 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0020-7608 J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD MAR PY 1991 VL 39 IS 3 BP 345 EP 352 DI 10.1002/qua.560390312 PG 8 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA EY446 UT WOS:A1991EY44600010 ER PT J AU AFZAL, SMJ TENFORDE, TS KAVANAU, KS CURTIS, SB AF AFZAL, SMJ TENFORDE, TS KAVANAU, KS CURTIS, SB TI REOXYGENATION IN A RAT RHABDOMYOSARCOMA TUMOR FOLLOWING X-IRRADIATION SO INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS LA English DT Article DE RAT RHABDOMYOSARCOMA TUMORS; REOXYGENATION; HYPOXIC FRACTION ID CHARGED-PARTICLE BEAMS; INDUCED GROWTH DELAY; HYPOXIC CELLS; CANCER-THERAPY; FRACTIONATED RADIOTHERAPY; RE-OXYGENATION; RIF-1 TUMOR; NEON-ION; RADIATION; SURVIVAL AB The paired survival curve technique was used to characterize the rate at which the fraction of hypoxic cells in rat rhabdomyosarcoma R-1 tumors returns to the preirradiation value of 37% following a single dose of 225-kVp X rays. Tumors were administered a conditioning x-ray dose of 15-Gy, followed at 0, 3, 6, 12, 24, or 48 hr by a 5-Gy, 10-Gy, or 15-Gy dose of X rays under air-breathing conditions or under hypoxic conditions produced by nitrogen-gas asphyxiation 5 min prior to irradiation. Cellular surviving fractions were determined by the tumor excision assay following in vivo irradiation. From the ratio of the survival fractions measured for tumor cells from air-breathing and hypoxic animals, the fraction of hypoxic cells was determined as a function of time postirradiation. These results indicated that immediately following a 15-Gy dose of X rays, essentially 100% of the viable cells remaining were hypoxic. The tumors reoxygenated rapidly, returning to the preirradiation level of 37% during the first 6 hr postirradiation. C1 PACIFIC NW LAB, CTR LIFE SCI, RICHLAND, WA 99352 USA. RP AFZAL, SMJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DIV CELL & MOLEC BIOL, BLDG 74, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. FU NCI NIH HHS [CA RO1-17411] NR 41 TC 9 Z9 9 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0360-3016 J9 INT J RADIAT ONCOL JI Int. J. Radiat. Oncol. Biol. Phys. PD MAR PY 1991 VL 20 IS 3 BP 473 EP 477 PG 5 WC Oncology; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Radiology, Nuclear Medicine & Medical Imaging GA EZ900 UT WOS:A1991EZ90000013 PM 1995533 ER PT J AU WANG, XW LOUIE, SG COHEN, ML AF WANG, XW LOUIE, SG COHEN, ML TI PREDICTING HIGH-PRESSURE AND EXCITED-STATE PROPERTIES OF REAL MATERIALS SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article ID RESOLVED INVERSE PHOTOEMISSION; SURFACE-STATES; ELECTRONIC-STRUCTURE; SOLIDS; GAAS(110); HYDROGEN; SUPERCONDUCTIVITY; GE(111); DIAMOND AB One of the breakthroughs in condensed matter physics is the newly acquired ability of theorists to explain and predict properties of solids using quantum theory. Starting with minimal information about the constituent atoms, the electronic, structural, vibrational, optical, and even superconducting properties of solids have been calculated accurately. Supercomputers have made these applications possible and have led to new theoretical concepts and techniques. The applications described here focus on the analysis of high-pressure properties of hydrogen, superhard compounds, and semiconductor surfaces. These calculations give results that are consistent with experimental data, and in some cases successfully predict properties of materials. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP WANG, XW (reprint author), UNIV CALIF BERKELEY,BERKELEY,CA 94720, USA. RI Schaff, William/B-5839-2009 NR 35 TC 2 Z9 2 U1 1 U2 2 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SPR PY 1991 VL 5 IS 1 BP 21 EP 33 DI 10.1177/109434209100500102 PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA FD719 UT WOS:A1991FD71900002 ER PT J AU FERREIRA, LG WEI, SH ZUNGER, A AF FERREIRA, LG WEI, SH ZUNGER, A TI STABILITY, ELECTRONIC-STRUCTURE, AND PHASE-DIAGRAMS OF NOVEL INTER-SEMICONDUCTOR COMPOUNDS SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article ID ALLOYS; EPITAXY; SOLIDS AB High-technology electronic devices are based on highly specialized core materials that make their operation possible: semiconductors. Unfortunately, the range of material properties that make high-technology devices work is extremely narrow, since the sheer number of useful semiconductors is small. Hence, a major challenge has been to predict and develop new, potentially useful semiconductors. We describe here how the use of state-of-the-art techniques in both quantum and statistical mechanics can lead to predictions of new, stable, and ordered semiconductor alloys. A number of laboratories have already grown experimentally these new materials; efforts to characterize their useful material properties are ongoing in the United States, Japan, and Europe. This work describes the theoretical methodologies of our approach, and shows how supercomputers make possible the quantum-mechanical architectural analysis of new materials. C1 UNIV SAO PAULO, INST PHYS, SAO PAULO, BRAZIL. SOLAR ENERGY RES INST, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 32 TC 80 Z9 80 U1 0 U2 13 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SPR PY 1991 VL 5 IS 1 BP 34 EP 56 DI 10.1177/109434209100500103 PG 23 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA FD719 UT WOS:A1991FD71900003 ER PT J AU AOYAGI, M SHEPARD, R WAGNER, AF AF AOYAGI, M SHEPARD, R WAGNER, AF TI AN ABINITIO THEORETICAL-STUDY OF THE CH+H-2 REVERSIBLE CH3-STAR REVERSIBLE CH2+H REACTIONS SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article ID RATE CONSTANTS; CH; KINETICS; HYDROGEN; SPECTROSCOPY; MECHANISMS; PRESSURES; METHYLENE; DYNAMICS; LASER AB Ab initio calculations of the electronic wave function and associated potential energy of CH3 at geometries appropriate for the title reaction described here allow characterization of the reactants and the energetically most favorable routes that are followed during the reaction. The quantum mechanical description of the electronic motion at each molecular geometry involves the response of each electron to the average field of all other electrons and the approximate correlated response of each electron to the instantaneous position of the other electrons. The basic methodology for the computation of this wave function, using extensive orbital basis sets and large-scale configuration expansions, is described. This calculation is one of the largest ever attempted for the characterization of a polyatomic reaction path. However, the path description involves a fine balance of energy contributions that requires this level of sophistication. The calculated properties of the reactants, the intermediate CH3, and the reaction paths to form CH3 are presented. The computed energetics compare favorably to experimental results. C1 ARGONNE NATL LAB, THEORET CHEM GRP, ARGONNE, IL 60439 USA. NR 38 TC 14 Z9 14 U1 0 U2 3 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SPR PY 1991 VL 5 IS 1 BP 72 EP 89 DI 10.1177/109434209100500105 PG 18 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA FD719 UT WOS:A1991FD71900005 ER PT J AU GRAVES, RS KOLLIE, TG MCELROY, DL GILCHRIST, KE AF GRAVES, RS KOLLIE, TG MCELROY, DL GILCHRIST, KE TI THE THERMAL-CONDUCTIVITY OF AISI 304L STAINLESS-STEEL SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE ELECTRICAL RESISTIVITY; SEEBECK COEFFICIENT; THERMAL CONDUCTIVITY; THERMAL DIFFUSIVITY; 304 STAINLESS STEEL AB A compilation and critical analysis of the thermal conductivity (lambda) of AISI 304 stainless steel (SS) between 100 and 1707 K has been given in the literature. The author represented his "recommended" values of lambda by an inflection in the lambda versus temperature relationship between 300 and 500 K. Because a physical mechanism had not been identified that would produce such a temperature dependence in lambda of 304 SS, interest was generated in the possible existence of an as yet undiscovered phenomenon that might cause such an inflection. Consequently, experimental verification of the inflection was sought. The present paper presents recent measurements of lambda, the electrical resistivity, and the absolute Seebeck coefficient of 304L SS from 300 to 1000 K and of the thermal diffusivity (alpha) from 297 to 423 K. The lambda values computed from the alpha measurements were within +/- 1.6% of the directly measured lambda. An inflection was not observed in the temperature dependence of lambda between 300 and 500 K. After careful evaluation and because a physical mechanism still has not been identified which would produce such an inflection, the authors conclude that the inflection in the lambda vs T relationship reported in the literature was caused by the data analysis technique. C1 UKAEA,AEA TECHNOL,SPRINGFIELDS LAB,PRESTON PR4 0RR,LANCS,ENGLAND. RP GRAVES, RS (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 8 TC 21 Z9 22 U1 1 U2 17 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAR PY 1991 VL 12 IS 2 BP 409 EP 415 DI 10.1007/BF00500761 PG 7 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA FC434 UT WOS:A1991FC43400014 ER PT J AU ROSS, MH SOCOLOW, RH AF ROSS, MH SOCOLOW, RH TI FULFILLING THE PROMISE OF ENVIRONMENTAL TECHNOLOGY SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Article C1 ARGONNE NATL LAB,ARGONNE,IL 60439. PRINCETON UNIV,CTR ENERGY & ENVIRONM STUDIES,PRINCETON,NJ 08544. PRINCETON UNIV,DEPT MECH & AEROSP ENGN,PRINCETON,NJ 08544. RP ROSS, MH (reprint author), UNIV MICHIGAN,PHYS,ANN ARBOR,MI 48109, USA. NR 9 TC 4 Z9 4 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SPR PY 1991 VL 7 IS 3 BP 61 EP 66 PG 6 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FG743 UT WOS:A1991FG74300044 ER PT J AU FRI, RW AF FRI, RW TI THE PRIZE - THE QUEST FOR OIL, MONEY, AND POWER - YERGIN,D SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Book Review C1 US DOE,ENERGY RES ADVISORY BOARD,WASHINGTON,DC. RP FRI, RW (reprint author), RESOURCES FUTURE INC,WASHINGTON,DC 20036, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SPR PY 1991 VL 7 IS 3 BP 95 EP 97 PG 3 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FG743 UT WOS:A1991FG74300052 ER PT J AU LEHNERT, BE TOEVS, KE SEBRING, RJ VALDEZ, YE AF LEHNERT, BE TOEVS, KE SEBRING, RJ VALDEZ, YE TI FAILURE OF A SIMPLE-MODEL OF ALVEOLAR MACROPHAGE-MEDIATED PARTICLE CLEARANCE TO DEPICT PARTICLE-ALVEOLAR MACROPHAGE RELATIONSHIPS DURING EARLY ALVEOLAR PHASE CLEARANCE SO JOURNAL OF AEROSOL MEDICINE-DEPOSITION CLEARANCE AND EFFECTS IN THE LUNG LA English DT Article DE LUNG CLEARANCE; ALVEOLAR MACROPHAGES; ALVEOLAR MACROPHAGE-MEDIATED CLEARANCE; PARTICLE REDISTRIBUTION PHENOMENON AB Little experimental attention has been given to examining the relationship(s) between particles retained in the alveolar space compartment and the lung's population of alveolar macrophages (AM) during alveolar phase clearance. In this study, we quantitatively characterized the distributions of particles among lavageable AM over a 30 day period after the acute intratracheal instillation of approximately 1.5 mg of 1.9-mu-m diam. polystyrene microspheres into the lungs of rats. Information obtained for particles retained in the lavageable AM compartment and particle-AM distribution data were collectively examined using a simple, first order kinetic model for AM removal from the lung. The results of our analyses suggest that a volume load of particles in a macrophage up to at least approximately 360-mu-m3 does not inhibit the mobilization of macrophages from the alveolar compartment. Additionally, the kinetic analyses of the particle-macrophage distributions suggest that some macrophages that replenish those AM that are translocated from the lung on a continual basis during alveolar clearance are not and/or do not remain particle-free in the alveoli. This latter observation can be explained by a redistribution of particles among the lung's population of AM during alveolar phase clearance, although the influx of particle-bearing interstitial macrophages into the alveoli may also be a contributing factor. RP LEHNERT, BE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,PUL BIOL TOXICOL SECT,CELLULAR & MOLEC BIOL GRP,LOS ALAMOS,NM 87545, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 0894-2684 J9 J AEROSOL MED JI J. Aerosol Med.-Depos. Clear. Eff. Lung PD SPR PY 1991 VL 4 IS 1 BP 41 EP 56 DI 10.1089/jam.1991.4.41 PG 16 WC Public, Environmental & Occupational Health; Respiratory System SC Public, Environmental & Occupational Health; Respiratory System GA FF317 UT WOS:A1991FF31700003 ER PT J AU LUK, VK FORRESTAL, MJ AMOS, DE AF LUK, VK FORRESTAL, MJ AMOS, DE TI DYNAMIC SPHERICAL CAVITY EXPANSION OF STRAIN-HARDENING MATERIALS SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article AB We developed models for the dynamic expansion of spherical cavities from zero initial radii for elastic-plastic, rate-independent materials with power-law strain hardening. The models considered the material as incompressible and compressible. For an incompressible material, we obtained closed-form solutions, whereas the compressible results required the numerical solution of differential equations. A comparison of the numerical results from both models showed the effect of compressibility. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 20 TC 64 Z9 82 U1 4 U2 13 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD MAR PY 1991 VL 58 IS 1 BP 1 EP 6 DI 10.1115/1.2897150 PG 6 WC Mechanics SC Mechanics GA HP715 UT WOS:A1991HP71500001 ER PT J AU FORRESTAL, MJ BRAR, NS LUK, VK AF FORRESTAL, MJ BRAR, NS LUK, VK TI PENETRATION OF STRAIN-HARDENING TARGETS WITH RIGID SPHERICAL-NOSE RODS SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article AB We developed engineering models that predict forces and penetration depth for long, rigid rods with spherical noses and rate-independent, strain-hardening targets. The spherical cavity expansion approximation simplified the target analysis, so we obtained closed-form penetration equations that showed the geometric and material scales. To verify our models, we conducted terminal-ballistic experiments with three projectile geometries made of maraging steel and 6061-T651 aluminum targets. The models predicted penetration depths that were in good agreement with the data for impact velocities between 0.3 and 1.0 km/s. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. UNIV DAYTON,RES INST,DAYTON,OH 45469. NR 8 TC 61 Z9 74 U1 1 U2 7 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD MAR PY 1991 VL 58 IS 1 BP 7 EP 10 DI 10.1115/1.2897183 PG 4 WC Mechanics SC Mechanics GA HP715 UT WOS:A1991HP71500002 ER PT J AU FERRARE, RA SCHOLS, JL ELORANTA, EW COULTER, R AF FERRARE, RA SCHOLS, JL ELORANTA, EW COULTER, R TI LIDAR OBSERVATIONS OF BANDED CONVECTION DURING BLX83 SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID PLANETARY BOUNDARY-LAYER; HORIZONTAL ROLL; DYNAMICS AB Lidar observations of clear-air convection during the 1983 Boundary Layer Experiment (BLX83) reveal the presence of elongated, parallel regions of updrafts marked by enhanced aerosol backscattering. These linear (banded) aerosol structures were observed over a two-hour period during a cloud-free morning. During this period, the depth of the convective boundary layer (CBL) increased from 100 to 1300 m. Wind speeds averaged over the depth of the CBL varied between 0 and 2 m s-1, while the wind direction varied over a range of 160 deg. The CBL instability parameter, -Z(i)/L, increased from approximately 25 (weekly unstable) to 250 (strongly unstable). The spacings of the elongated, parallel plumes scaled with the CBL height. These findings suggest that secondary circulations in the form of horizontal roll vortices were present under conditions not normally associated with roll vortices. The lines of aerosol structures aligned much more closely (within 15 deg) with the direction of the vertical shear of the horizontal wind through the depth of the CBL than with either the surface wind, mean CBL wind, or the wind at an altitude of 1.1Z(i). C1 UNIV WISCONSIN,DEPT METEOROL,MADISON,WI 53706. ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. NR 32 TC 33 Z9 33 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAR PY 1991 VL 30 IS 3 BP 312 EP 326 DI 10.1175/1520-0450(1991)030<0312:LOOBCD>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FJ114 UT WOS:A1991FJ11400004 ER PT J AU SCHMIDT, SC SCHIFERL, D ZINN, AS RAGAN, DD MOORE, DS AF SCHMIDT, SC SCHIFERL, D ZINN, AS RAGAN, DD MOORE, DS TI CALIBRATION OF THE NITROGEN VIBRON PRESSURE SCALE FOR USE AT HIGH-TEMPERATURES AND PRESSURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DENSE FLUID NITROGEN; LIQUID-NITROGEN; THERMODYNAMICS; SPECTROSCOPY; EQUATION; STATE AB Coherent anti-Strokes Raman scattering (CARS) and spontaneous Raman spectroscopy have been used to obtain vibrational spectra of shock-compressed and static high-pressure fluid nitrogen, respectively. Vibrational frequencies were obtained from the CARS data using a semiclassical model for these spectra. Spontaneous Raman vibrational frequencies were determined by fitting data using a Lorentz-shape line. A functional form was found for the dependence of the vibrational frequency on pressure and temperature to 40 GPa and 5000 K, respectively. By fitting the vibrational data to this form, a pressure scale based on the fluid nitrogen vibron has been calibrated for use at very high temperature. The nitrogen vibron pressure scale was used to determine the fluid-delta nitrogen phase boundary up to 20 GPa and 900 K. RP SCHMIDT, SC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Moore, David/C-8692-2013 NR 30 TC 33 Z9 33 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 2793 EP 2799 DI 10.1063/1.348638 PG 7 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500005 ER PT J AU MITCHELL, AC NELLIS, WJ MORIARTY, JA HEINLE, RA HOLMES, NC TIPTON, RE REPP, GW AF MITCHELL, AC NELLIS, WJ MORIARTY, JA HEINLE, RA HOLMES, NC TIPTON, RE REPP, GW TI EQUATION OF STATE OF AL, CU, MO, AND PB AT SHOCK PRESSURES UP TO 2.4 TPA (24-MBAR) SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID COMPRESSION; ALUMINUM; COPPER; MOLYBDENUM; POTENTIALS; SYSTEM AB Equation-of-state data and corresponding first-principles theory for the metals Al, Cu, Mo, and Pb are reported over the shock pressure range 0.4-2.4 TPa (4-24 Mbar). Strong shock waves were generated by nuclear explosions and a two-stage light-gas gun. The experimental data occur in the hot liquid-metal regime, where condensed-matter theory applies but with unusually large thermal components to the equation of state. RP MITCHELL, AC (reprint author), LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NR 34 TC 103 Z9 104 U1 1 U2 17 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 MAR 1 PY 1991 VL 69 IS 5 BP 2981 EP 2986 DI 10.1063/1.348611 PG 6 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500032 ER PT J AU CHAN, LY YU, KM BENTZUR, M HALLER, EE JAKLEVIC, JM WALUKIEWICZ, W HANSON, CM AF CHAN, LY YU, KM BENTZUR, M HALLER, EE JAKLEVIC, JM WALUKIEWICZ, W HANSON, CM TI LATTICE LOCATION OF DIFFUSED ZN ATOMS IN GAAS AND INP SINGLE-CRYSTALS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID N-TYPE; SUBSTITUTIONAL ZN; INDIUM-PHOSPHIDE; ZINC; SEMICONDUCTORS; INGAASP; DEFECTS AB We have investigated the saturation phenomenon of the free carrier concentration in p-type GaAs and InP single crystals doped by zinc diffusion. The free hole saturation occurs at 10(20) cm-3 for GaAs, but the maximum concentration for InP appears at mid 10(18) cm-3. The difference in the saturation hole concentrations for these materials is investigated by studying the incorporation and the lattice location of the impurity zinc, an acceptor when located on a group III atom site. Zinc is diffused into the III-V wafers in a sealed quartz ampoule. Particle-induced x-ray emission with ion-channeling techniques are employed to determine the exact lattice location of the zinc atoms. We have found that over 90% of all zinc atoms occupy Ga sites in the diffused GaAs samples, while for the InP case, the zinc substitutionality is dependent on the cooling rate of the sample after high-temperature diffusion. For the slowly cooled sample, a large fraction (approximately 90%) of the zinc atoms form random precipitates of Zn3P2 and elemental Zn. However, when rapidly cooled only 60% of the zinc forms such precipitates while the rest occupies specific sites in the InP. We analyze our results in terms of the amphoteric native defect model. We show that the difference in the electrical activity of the Zn atoms in GaAs and InP is a consequence of the different location of the Fermi level stabilization energy in these two materials. C1 LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RI Yu, Kin Man/J-1399-2012 OI Yu, Kin Man/0000-0003-1350-9642 NR 29 TC 31 Z9 31 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 2998 EP 3006 DI 10.1063/1.348613 PG 9 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500034 ER PT J AU WAMPLER, WR AF WAMPLER, WR TI SURFACE-LIMITED RELEASE OF DEUTERIUM FROM TANTALUM SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HYDROGEN; METALS; TA; NB AB The release of deuterium (D) from solution in tantalum (Ta) was examined. Nuclear reaction analysis was used to measure the concentration of D in solution during isothermal release of the D. The rate-controlling process for D release was molecular recombination at the surface. The release followed second-order kinetics, which shows that the recombination occurs from sites which have a binding energy for the D less than or equal to the energy of solution. Recombination therefore cannot be occurring from the more strongly bound low-coverage chemisorption sites. A model for the release rate which uses no free parameters is described. Experimentally determined recombination coefficients for Ta, Pd, and Fe spanning 18 orders of magnitude are in good agreement with the model. RP WAMPLER, WR (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 11 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 3063 EP 3067 DI 10.1063/1.348567 PG 5 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500044 ER PT J AU AHRENKIEL, RK KEYES, BM SHEN, TC CHYI, JI MORKOC, H AF AHRENKIEL, RK KEYES, BM SHEN, TC CHYI, JI MORKOC, H TI MINORITY-CARRIER LIFETIME IN ALXGA1-XAS GROWN BY MOLECULAR-BEAM EPITAXY SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID (AL,GA)AS EPILAYERS; LASERS AB Al(x) Ga(1-x)As (x > 0.30) double heterostructures are grown by molecular-beam epitaxy (MBE) and the minority-carrier lifetimes are measured by time-resolved photoluminescence. The data indicate that the minority-carrier lifetime in high aluminum (x > 0.30) Al(x)Ga(1-x)As grown by MBE are comparable to the previously published lifetimes of material grown by liquid-phase epitaxy. The lifetimes in MBE materials appear to be somewhat larger than those measured in materials grown by metalorganic chemical vapor deposition. Factors affecting AlGaAs minority-carrier lifetime, such as the growth temperature, the aluminum concentration, and the confinement layer composition will be discussed. C1 UNIV ILLINOIS,COORDINATED SCI LAB,URBANA,IL 61801. RP AHRENKIEL, RK (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Chyi, Jen-Inn/A-1799-2016 NR 12 TC 11 Z9 11 U1 3 U2 7 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 MAR 1 PY 1991 VL 69 IS 5 BP 3094 EP 3096 DI 10.1063/1.348573 PG 3 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500050 ER PT J AU SCHUBERT, WK AF SCHUBERT, WK TI COMPARISON OF THE EFFECTS OF POST-OXIDATION ANNEALS ON THE INITIAL PROPERTIES AND THE RADIATION RESPONSE OF RAPID THERMALLY PROCESSED OXIDES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRON-SPIN-RESONANCE; SI-SIO2 INTERFACE; SILICON DIOXIDE; GATE DIELECTRICS; NITRIDATION; SIO2; SIO2-FILMS; INJECTION; STATES; IRRADIATION AB The effects of post-oxidation processing on the initial performance (as measured here by pre-irradiation fixed-charge and interface-state densities) and radiation response of rapid thermally processed, metal-oxide-semiconductor (MOS) capacitors are investigated. The processing dependencies for the major groups of processing- and radiation-induced defects are discussed with respect to recent gains in understanding of the Si-SiO2 interfacial structure. Processing conditions for ideal initial properties are found to be quite different than those required for optimum radiation response. Guidelines for optimal post-oxidation thermal processing are given, taking into consideration both the initial performance and radiation response of the MOS device. The results indicate that even when using rapid thermal processing, post-gate oxide anneals above 900-degrees-C degrade the radiation tolerance. RP SCHUBERT, WK (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 43 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 3159 EP 3166 DI 10.1063/1.348585 PG 8 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500062 ER PT J AU BASU, SN MITCHELL, TE NASTASI, M AF BASU, SN MITCHELL, TE NASTASI, M TI ELECTRON-BEAM-IRRADIATION EFFECTS IN BULK YBA2CU3O7-X SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PHASE-STABILITY AB Irradiation effects on thin foils of bulk YBa2Cu3O7-x have been studied in a transmission electron microscope using 100-, 150-, 200-, 250-, and 300-keV electrons at 83 and 300 K. The disordering of the oxygen atoms and vacancies in the O(4) and O(5) sites in the Cu-O planes during irradiation was monitored by measuring the splitting of the (11BAR0) diffraction spots in the [001] diffraction pattern. The results show that YBa2Cu3O7-x is insensitive to 100-keV electron irradiation. Irradiation by higher-energy electrons leads to irradiation-induced oxygen disordering of the oxygen atoms and vacancies, mainly by single displacement events. The excellent fit of the data to a disordering model suggests that the displacement threshold energy for oxygen in YBa2Cu3O7-x is around 18 eV and that irradiation-assisted oxygen reordering occurs in YBa2Cu3O7-x at 300 K, but not at 83 K. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 14 TC 29 Z9 29 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 MAR 1 PY 1991 VL 69 IS 5 BP 3167 EP 3171 DI 10.1063/1.348586 PG 5 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500063 ER PT J AU HERZOG, R WEBER, HW KAMPWIRTH, RT GRAY, KE GERSTENBERG, H AF HERZOG, R WEBER, HW KAMPWIRTH, RT GRAY, KE GERSTENBERG, H TI LOW-TEMPERATURE NEUTRON-IRRADIATION OF MAGNETRON-SPUTTERED NBN FILMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SUPERCONDUCTORS AB Four types of differently prepared NbN films were irradiated at 4.6 K with fast neutrons to a fluence of 5.3 x 10(22) m-2 (E > 0.1 MeV). The critical current densities J(c) were measured in magnetic fields up to 23 T prior to irradiation, following low-temperature irradiation, and again after an annealing cycle to room temperature. In all films, J(c) was found to be completely unchanged by the radiation and annealing treatments in fields up to 15 T, but to increase at higher magnetic fields. At the same time, the upper critical fields B(c2) increased by about 0.5 T (approximately 2%). Replotting J(c) versus reduced field B/B(c2) leads to identical field dependencies also in the high-field range. Hence, the observed increase of J(c) is equantitatively explained as a B(c2) effect. C1 MAX PLANCK INST SOLID STATE RES,FESTKORPERFORSCH,HIGH FIELD MAGNET LAB,F-38042 GRENOBLE,FRANCE. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. TECH UNIV MUNICH,FAK PHYS E21,W-8046 GARCHING,GERMANY. RP HERZOG, R (reprint author), UNIV VIENNA,ATOMINST,A-1020 VIENNA,AUSTRIA. NR 7 TC 2 Z9 2 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 3172 EP 3175 DI 10.1063/1.348557 PG 4 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500064 ER PT J AU SRINIVASANRAO, T FISCHER, J TSANG, T AF SRINIVASANRAO, T FISCHER, J TSANG, T TI PHOTOEMISSION-STUDIES ON METALS USING PICOSECOND ULTRAVIOLET-LASER PULSES SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB We report the quantum efficiency of various metals irradiated by 266-nm, 4.66-eV laser pulses of 10-ps duration. The highest quantum efficiency obtained is 7.25 x 10(-4) with samarium photocathodes. Current densities exceeding 66 and 21 kA/cm2 have been obtained from an area of 0.05 and 7 mm2, respectively. The maximum currents and current densities obtainable in these experiments are limited by the space charge. For surface fields exceeding 5 x 10(7) V/m on gold, the efficiency increases linearly with the field for the values investigated. Based on the quantum efficiency and optical damage threshold measurements, current densities exceeding 100 kA/cm2 seem feasible without damaging the photocathode. RP SRINIVASANRAO, T (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 14 TC 79 Z9 82 U1 3 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1991 VL 69 IS 5 BP 3291 EP 3296 DI 10.1063/1.348550 PG 6 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500081 ER PT J AU COBBLE, JA SCHAPPERT, GT JONES, LA TAYLOR, AJ KYRALA, GA FULTON, RD AF COBBLE, JA SCHAPPERT, GT JONES, LA TAYLOR, AJ KYRALA, GA FULTON, RD TI THE INTERACTION OF A HIGH IRRADIANCE, SUBPICOSECOND LASER-PULSE WITH ALUMINUM - THE EFFECTS OF THE PREPULSE ON X-RAY-PRODUCTION SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID PLASMAS; SPECTROSCOPY; EXPANSION; EMISSION AB The conversion efficiency into kilovolt line radiation for 248-nm light at 10(17) W/cm2 on an aluminum target is measured. The x-ray yield is found to increase with the scale length of the target plasma. The interaction is modeled as resonance absorption, and the plasma scale length is determined from the prelase energy and irradiance. RP COBBLE, JA (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 15 TC 50 Z9 50 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 MAR 1 PY 1991 VL 69 IS 5 BP 3369 EP 3371 DI 10.1063/1.348536 PG 3 WC Physics, Applied SC Physics GA FA705 UT WOS:A1991FA70500096 ER PT J AU HOFFECKER, JF BARYSHNIKOV, G POTAPOVA, O AF HOFFECKER, JF BARYSHNIKOV, G POTAPOVA, O TI VERTEBRATE REMAINS FROM THE MOUSTERIAN SITE OF ILSKAYA-I (NORTHERN CAUCASUS, USSR) - NEW ANALYSIS AND INTERPRETATION SO JOURNAL OF ARCHAEOLOGICAL SCIENCE LA English DT Article DE FAUNAL ANALYSIS; MOUSTERIAN; EUROPEAN USSR; SUBSISTENCE STRATEGY; BISON PROCUREMENT; LATE PLEISTOCENE PALEOECOLOGY ID ARCHAEOLOGICAL SITES; BISON; PROFILES C1 ACAD SCI USSR,INST ZOOL,LENINGRAD 199034,USSR. RP HOFFECKER, JF (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 99 TC 36 Z9 40 U1 0 U2 9 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0305-4403 J9 J ARCHAEOL SCI JI J. Archaeol. Sci. PD MAR PY 1991 VL 18 IS 2 BP 113 EP 147 DI 10.1016/0305-4403(91)90043-O PG 35 WC Anthropology; Archaeology; Geosciences, Multidisciplinary SC Anthropology; Archaeology; Geology GA FB999 UT WOS:A1991FB99900001 ER PT J AU GEHRING, K CHENG, CH NIKAIDO, H JAP, BK AF GEHRING, K CHENG, CH NIKAIDO, H JAP, BK TI STOICHIOMETRY OF MALTODEXTRIN-BINDING SITES IN LAMB, AN OUTER-MEMBRANE PROTEIN FROM ESCHERICHIA-COLI SO JOURNAL OF BACTERIOLOGY LA English DT Article ID RECEPTOR PROTEIN; SUGAR-TRANSPORT; MALTOPORIN; DIFFUSION; CHANNEL; MALTOSE; SELECTIVITY; SPECIFICITY; MUTATIONS; PORIN AB We have directly measured the stoichiometry of maltodextrin-binding sites in LamB. Scatchard plots and computer fitting of flow dialysis (rate-of-dialysis) experiments clearly establish three independent binding sites per LamB trimer, with a dissociation constant of approximately 60-mu-M for maltoheptaose. The current model for LamB's function as a specific pore is discussed with respect to the symmetry in LamB's kinetic properties and the implications of our results. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720. RP GEHRING, K (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Gehring, Kalle/I-4403-2013 OI Gehring, Kalle/0000-0001-6500-1184 FU NCRR NIH HHS [RR05918]; NIAID NIH HHS [AI-09644]; NIGMS NIH HHS [GM36884] NR 28 TC 10 Z9 11 U1 0 U2 0 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 MAR PY 1991 VL 173 IS 6 BP 1873 EP 1878 PG 6 WC Microbiology SC Microbiology GA FB988 UT WOS:A1991FB98800006 PM 2001992 ER PT J AU LASHIER, ME SCHRADER, GL AF LASHIER, ME SCHRADER, GL TI REACTIVE LATTICE OXYGEN SITES FOR C4-HYDROCARBON SELECTIVE OXIDATION OVER BETA-VOPO4 SO JOURNAL OF CATALYSIS LA English DT Article ID P-O CATALYSTS; PHOSPHORUS OXIDE CATALYSTS; MALEIC-ANHYDRIDE SYNTHESIS; NORMAL-BUTANE OXIDATION; INSITU FTIR; P/V RATIO; VANADIUM; 1-BUTENE; BUTADIENE; MECHANISM C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM ENGN,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 51 TC 31 Z9 32 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD MAR PY 1991 VL 128 IS 1 BP 113 EP 125 DI 10.1016/0021-9517(91)90071-B PG 13 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA FP922 UT WOS:A1991FP92200011 ER PT J AU JAGUST, WJ SEAB, JP HUESMAN, RH VALK, PE MATHIS, CA REED, BR COXSON, PG BUDINGER, TF AF JAGUST, WJ SEAB, JP HUESMAN, RH VALK, PE MATHIS, CA REED, BR COXSON, PG BUDINGER, TF TI DIMINISHED GLUCOSE-TRANSPORT IN ALZHEIMERS-DISEASE - DYNAMIC PET STUDIES SO JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM LA English DT Article DE ALZHEIMERS DISEASE; GLUCOSE METABOLISM; GLUCOSE TRANSPORT; POSITRON EMISSION TOMOGRAPHY ID POSITRON EMISSION TOMOGRAPHY; BLOOD-BRAIN-BARRIER; RATE CONSTANTS; METABOLIC-RATE; F-18 FLUORODEOXYGLUCOSE; LUMPED CONSTANT; NORMAL VALUES; DEMENTIA; DEOXYGLUCOSE; HUMANS AB Dynamic positron emission tomography with [F-18]fluorodeoxyglucose was used in six patients with Alzheimer's disease (AD) and seven healthy age-matched control subjects to estimate the kinetic parameters K1*, k2*, and k3* that describe glucose transport and phosphorylation. A high-resolution tomograph was used to acquire brain uptake data in one tomographic plane, and a radial artery catheter connected to a plastic scintillator was used to acquire arterial input data. A nonlinear interative least-squares fitting procedure that included terms for the vascular fraction and time delay to the peripheral sampling site was used to fit a three-compartment model to the brain data. Regions studied included frontal, temporal, occipital, and the entire cortex and subcortical white matter. The values obtained for the individual rate constants and regional CMR(glc) (rCMR(glc); calculated using regional values of the rate constants) were higher than those reported previously. A significant (p < 0.05) decrease was found in K1* in frontal and temporal cortex in the AD patients compared with the controls, with values of 0.157 and 0.161 ml/g/min in frontal and temporal cortex, respectively, of controls and 0.127 and 0.126 ml/g/min in frontal and temporal cortex of the AD patients. rCMR(glc) was also significantly (p < 0.02) lower in the AD patients than controls in all cortical brain regions. Lower values of k3* were found in all brain regions in the AD patients, although these were not statistically significant. These findings provide evidence of an in vivo abnormality of forward glucose transport in AD. This transport defect, however, is probably not the cause of the diminution in glucose metabolism that has been widely found in AD patients, since a diminution of this magnitude should not lower intracerebral glucose content enough to alter rCM-R(glc). C1 UNIV CALIF DAVIS,DAVIS,CA 95616. VET ADM MED CTR,DEPT NEUROL,MARTINEZ,CA 94553. RP JAGUST, WJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DONNER LAB,55-121,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NIA NIH HHS [AG07793, AG05890] NR 33 TC 124 Z9 126 U1 1 U2 5 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0271-678X J9 J CEREBR BLOOD F MET JI J. Cereb. Blood Flow Metab. PD MAR PY 1991 VL 11 IS 2 BP 323 EP 330 PG 8 WC Endocrinology & Metabolism; Hematology; Neurosciences SC Endocrinology & Metabolism; Hematology; Neurosciences & Neurology GA EZ346 UT WOS:A1991EZ34600016 PM 1997504 ER PT J AU LEVY, AV LASKA, E BRODIE, JD VOLKOW, ND WOLF, AP AF LEVY, AV LASKA, E BRODIE, JD VOLKOW, ND WOLF, AP TI THE SPECTRAL SIGNATURE METHOD FOR THE ANALYSIS OF PET BRAIN IMAGES SO JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM LA English DT Article; Proceedings Paper CT WORKSHOP ON PET ( POSITRON EMISSION TOMOGRAPHY ) DATA ANALYSIS CY MAY 01-02, 1989 CL NEW YORK, NY DE BRAIN ASYMMETRIES; CEREBRAL GLUCOSE METABOLISM; NEURAL PATTERNS; SCHIZOPHRENIA; SPECTRAL SIGNATURE; 3-DIMENSIONAL PATTERN ANALYSIS ID POSITRON EMISSION TOMOGRAPHY; CHRONIC-SCHIZOPHRENIA; COMPUTED-TOMOGRAPHY; GLUCOSE-METABOLISM; BASAL GANGLIA; ABNORMALITIES; LOCALIZATION; DISORDERS; GRADIENTS; ASYMMETRY AB We introduce the concept of the metabolic centroid spectrum as the feature space to characterize the distribution of metabolic activity in three-dimensional brains. The method computes the metabolic centroid of a brain subvolume for each increment of metabolic activity occurring in the whole brain. The result is the metabolic spectral signature, a continuous three-dimensional curve whose shape reflects the distribution of metabolic rates in the brain. The method's sensitivity to metabolic distribution asymmetries is greatly increased over that of the metabolic centroid method, while retaining its advantages; it is almost invariant to head size, head positioning, photon scatter, and the positron emission tomography (PET) camera's full width at half-maximum. It does not require magnetic resonance, computed tomography, or x-ray images. To test the method we analyzed the metabolic PET images of 40 normal subjects and 20 schizophrenics. The results show a unification of several metabolic characteristics of schizophrenic brains, such as laterality, hyprofrontality, cortical/subcortical abnormalities, and overall brain hypometabolism, which were identified by different laboratories in separate studies using differing methodologies. Here they are presented by a single automatic objective method. C1 NYU MED CTR,DEPT PSYCHIAT,NEW YORK,NY 10016. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP LEVY, AV (reprint author), NATHAN S KLINE INST PSYCHIAT RES,DIV STAT SCI & EPIDEMIOL,ORANGEBURG,NY 10962, USA. FU NIMH NIH HHS [MH44832, MH42959]; NINDS NIH HHS [NS 15638] NR 46 TC 9 Z9 9 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0271-678X J9 J CEREBR BLOOD F MET JI J. Cereb. Blood Flow Metab. PD MAR PY 1991 VL 11 IS 2 BP A103 EP A113 PG 11 WC Endocrinology & Metabolism; Hematology; Neurosciences SC Endocrinology & Metabolism; Hematology; Neurosciences & Neurology GA EZ346 UT WOS:A1991EZ34600037 PM 1997478 ER PT J AU DEHMER, PM HOLLAND, DMP AF DEHMER, PM HOLLAND, DMP TI PHOTOIONIZATION OF ROTATIONALLY COOLED H2O AND D2O IN THE REGION 650-990-A SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SINGLET EXCITED-STATES; VACUUM ULTRAVIOLET; HIGH-RESOLUTION; CROSS-SECTIONS; RYDBERG STATES; PHOTOELECTRON-SPECTRA; ABSORPTION-SPECTRA; WATER-VAPOR; MOLECULES; IONIZATION AB Room temperature and rotationally cooled relative photoionization cross sections for H2O and D2O were determined in the wavelength region 650-990 angstrom with a wavelength resolution of 0.06-0.11 angstrom (approximately 7-12 cm-1); the spectra were normalized to the absolute photoionization cross sections determined by Katayama et al. [D. H. Katayama, R. E. Huffman, and C. L. O'Bryan, J. Chem. Phys. 59, 4309 (1973)] with lower resolution. A rotational analysis of the II subbands in the (0,6,0) and (0,8,0) bands of the (A approximately A2(1)) 3db1 B1(1) <-- X approximately A1(1) Rydberg transition determined the symmetry of the upper state; in addition, the series was extended to higher principal quantum numbers. The analysis of these and other bands was made difficult both by the large natural linewidths of the rotational transitions and by the absence of transitions of rotational levels with N' greater than or similar to 3. C1 SERC,DARESBURY LAB,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. RP DEHMER, PM (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 57 TC 9 Z9 9 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1991 VL 94 IS 5 BP 3302 EP 3314 DI 10.1063/1.459805 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800002 ER PT J AU DIBBLE, BG SHIRTS, RB AF DIBBLE, BG SHIRTS, RB TI THEORETICAL PREDICTION OF ULTRAHIGH VIBRATIONAL-EXCITATION USING INFRARED PICOSECOND PULSE TRAINS - COHERENT ABSORPTION OF SEVERAL PHOTONS EACH OF A DIFFERENT FREQUENCY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID N-LEVEL ATOMS; MORSE OSCILLATOR; LASER-PULSES; MULTI-PHOTON; CLASSICAL DYNAMICS; FLOQUET THEORY; QUANTUM; MOLECULES; FIELD; SYSTEMS AB Using an IR picosecond pulse train, ultrahigh vibrational excitation in a Morse oscillator is achieved. Following a suggestion by Paramonov and Savva, pulse-train parameters can be chosen such that within 100 pulses (about 20 ps) there is significant excitation into the eighth excited vibrational state. We improve on their work by (1) using physically realistic matrix elements and potential parameters; (2) using Floquet theory to more efficiently perform the numerical calculation; (3) discussing the molecular excitation sensitivity to pulse-train parameters: pulse spacing, pulse width, central laser frequency, and peak laser fluence; and (4) showing that the vibrational excitation is a coherent multicolor, multiphoton process. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. RP DIBBLE, BG (reprint author), DEPAUW UNIV,DEPT CHEM,GREENCASTLE,IN 46135, USA. NR 55 TC 19 Z9 19 U1 0 U2 2 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 MAR 1 PY 1991 VL 94 IS 5 BP 3451 EP 3467 DI 10.1063/1.459767 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800018 ER PT J AU JUDSON, RS MCGARRAH, DB SHARAFEDDIN, OA KOURI, DJ HOFFMAN, DK AF JUDSON, RS MCGARRAH, DB SHARAFEDDIN, OA KOURI, DJ HOFFMAN, DK TI A COMPARISON OF 3 TIME-DEPENDENT WAVE PACKET METHODS FOR CALCULATING ELECTRON ATOM ELASTIC-SCATTERING CROSS-SECTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYMMETRIC TRIATOMIC-MOLECULES; COLLINEAR H+H2 REACTION; FOURIER METHOD SOLUTION; SCHRODINGER-EQUATION; SURFACE SCATTERING; QUANTUM-MECHANICS; HYBRID MECHANICS; DYNAMICS; DISSOCIATION; PHOTOFRAGMENTATION AB We compare three time-dependent wave packet methods for performing elastic scattering calculations from screened Coulomb potentials. The three methods are the time-dependent amplitude density method (TDADM), what we term a Cayley-transform method (CTM), and the Chebyshev propagation method of Tal-Ezer and Kosloff. Both the TDADM and the CTM are based on a time-dependent integral equation for the wave function. In the first, we propagate the time-dependent amplitude density, \zeta(t)] = U\psi(t)], where U is the interaction potential and \psi(t)] is the usual time-dependent wave function. In the other two, the wave function is propagated. As a numerical example, we calculate phase shifts and cross sections using a screened Coulomb, Yukawa type potential over the range 200-1000 eV. One of the major advantages of time-dependent methods such as these is that we get scattering information over this entire range of energies from one propagation. We find that in most cases, all three methods yield comparable accuracy and are about equally efficient computationally. However for l = 0, where the Coulomb well is not screened by the centrifugal potential, the TDADM requires smaller grid spacings to maintain accuracy. C1 UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77204. UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP JUDSON, RS (reprint author), SANDIA NATL LABS,CTR COMPUTAT ENGN,LIVERMORE,CA 94551, USA. OI Judson, Richard/0000-0002-2348-9633 NR 58 TC 33 Z9 33 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1991 VL 94 IS 5 BP 3577 EP 3585 DI 10.1063/1.459729 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800032 ER PT J AU RAGHAVACHARI, K ROHLFING, CM AF RAGHAVACHARI, K ROHLFING, CM TI ELECTRONIC-STRUCTURES OF THE NEGATIVE-IONS SI-2--SI-10- - ELECTRON-AFFINITIES OF SMALL SILICON CLUSTERS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-ORBITAL METHODS; CAS SCF/CI CALCULATIONS; GAUSSIAN-BASIS SETS; SEMICONDUCTOR CLUSTERS; MAGIC NUMBERS; GROUND-STATE; PHOTOELECTRON-SPECTROSCOPY; CONFIGURATION-INTERACTION; EQUILIBRIUM STRUCTURES; PERTURBATION-THEORY AB Accurate ab initio calculations have been performed to investigate the structures and energies of the negative ions of Si2-Si10. The effects of polarization functions, diffuse functions, and electron correlation have been included in these calculations. In most cases, there is a good correspondence between the ground state structures of the negative ions and those of the corresponding neutral species. Adiabatic electron affinities are computed and compared with recent experimental measurements. Si3, Si5, Si8, and Si9 are found to have electron affinities which are larger than their neighbors. This result is interpreted using our previous calculations on the low-lying states of the corresponding neutral species. C1 SANDIA NATL LABS,DIV THEORET,LIVERMORE,CA 94551. RP RAGHAVACHARI, K (reprint author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA. NR 89 TC 179 Z9 184 U1 0 U2 20 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 MAR 1 PY 1991 VL 94 IS 5 BP 3670 EP 3678 DI 10.1063/1.459738 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800043 ER PT J AU VOS, WL SCHOUTEN, JA YOUNG, DA ROSS, M AF VOS, WL SCHOUTEN, JA YOUNG, DA ROSS, M TI THE MELTING CURVE OF NEON AT HIGH-PRESSURE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID EQUATION; STATE; ARGON AB We have measured the melting curve of neon to 54.5 kbar and 328 K using a diamond-anvil cell. The measured points together with earlier low-pressure data are fitted accurately with a Simon-Glatzel function. Theoretical calculations of the melting curve using lattice dynamics and variational fluid theory with exponential-six potentials fitted to solid isotherm data are in good agreement with the experimental data. The law of corresponding states is tested for the melting curves of He, Ne, and Ar, and is found to be obeyed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP VOS, WL (reprint author), UNIV AMSTERDAM,VAN DER WAALS LAB,VALCKENIERSTR 67,1018 XE AMSTERDAM,NETHERLANDS. RI Vos, Willem/B-7489-2012 OI Vos, Willem/0000-0003-3066-859X NR 17 TC 38 Z9 38 U1 0 U2 2 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 MAR 1 PY 1991 VL 94 IS 5 BP 3835 EP 3838 DI 10.1063/1.460683 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800061 ER PT J AU SCHWEIZER, KS CURRO, JG AF SCHWEIZER, KS CURRO, JG TI ANALYTIC REFERENCE INTERACTION SITE MODEL-MEAN SPHERICAL APPROXIMATION-THEORY OF FLEXIBLE POLYMER BLENDS - EFFECTS OF SPATIAL AND FRACTAL DIMENSIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTEGRAL-EQUATION THEORY; PHASE-SEPARATION; LIQUID-MIXTURES; MELTS; THERMODYNAMICS; FLUIDS; PARAMETER; DYNAMICS; STATE AB Recently developed methods for obtaining exact and approximate analytical solutions of the reference interaction site model-mean spherical approximation (RISM-MSA) integral equations for liquid mixtures composed of long, flexible polymers are applied to study the critical temperature T(c) for phase separation of symmetric isotopic binary blends as a function of degree of polymerization N, spatial dimension D, and fractal dimension d(f) of the individual macromolecules. For ideal random walk coils, the theory predicts a nonclassical behavior given by T(c) proportional-to N(D-2)/2 in two and three dimensions, and the classical Flory-Huggins mean field T(c) proportional-to N law is recovered in four and higher dimensions. For arbitrary interpenetrating polymeric fractals, the theory predicts T(c) proportional-to N(D-d(f))/d(f) for spatial dimensions below 2d(f) and Flory-Huggins behavior for D > 2d(f). These novel scaling laws for isotopic mixtures are a consequence of a consistent treatment of chain connectivity on all length scales, intermolecular excluded volume, and a short range unfavorable interaction between hydrogenated and deuterated polymers. A general, closure-independent physical argument based on a renormalization of the bare chi parameter by relatively long range correlated fluctuations in the blend is proposed which reproduces all the qualitative predictions of the RISM-MSA integral equation theory. Analogies with nonclassical critical fluctuation effects are established. Application of the analytical approach to purely athermal blends is also presented. The magnitude and composition dependence of the effective chi parameter is found to be a sensitive function of both spatial and fractal dimensions, and also local nonuniversal features. The various theoretical predictions are favorably compared with recent small angle neutron scattering measurements on binary polymer alloys. C1 SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. NR 65 TC 39 Z9 39 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1991 VL 94 IS 5 BP 3986 EP 4000 DI 10.1063/1.460704 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FA778 UT WOS:A1991FA77800080 ER PT J AU HUANG, JX SCHUDEL, J GUIOCHON, G AF HUANG, JX SCHUDEL, J GUIOCHON, G TI ADSORPTION BEHAVIOR OF SOME PROTEINS ON THE TSK-DEAE5PW ANION-EXCHANGER SO JOURNAL OF CHROMATOGRAPHIC SCIENCE LA English DT Article ID SEPARATION; PEPTIDES AB The adsorption isotherms of conalbumin, myoglobin, and gamma-globulin on TSK-DEAE 5PW are determined by frontal analysis using buffer solutions of different ionic strengths. The data are well accounted for by a bi-Langmuir isotherm model, corresponding to two types of adsorption sites with different adsorption energies. The column saturation capacity varies considerably from one protein to the other and for a given compound, depends strongly on the ionic strength of the mobile phase. This demonstrates that the composition of the mobile phase used in preparative liquid chromatography must be chosen carefully, to optimize the combined effect of the relative retention and of the column saturation capacity on the production rate, not either one of these factors. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 10 TC 11 Z9 12 U1 0 U2 0 PU PRESTON PUBLICATIONS INC PI NILES PA 7800 MERRIMAC AVE PO BOX 48312, NILES, IL 60648 SN 0021-9665 J9 J CHROMATOGR SCI JI J. Chromatogr. Sci. PD MAR PY 1991 VL 29 IS 3 BP 122 EP 126 PG 5 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA FA703 UT WOS:A1991FA70300006 ER PT J AU KATTI, AM DOSE, EV GUIOCHON, G AF KATTI, AM DOSE, EV GUIOCHON, G TI COMPARISON OF THE PERFORMANCES OF OVERLOADED ELUTION AND DISPLACEMENT CHROMATOGRAPHY FOR A GIVEN COLUMN SO JOURNAL OF CHROMATOGRAPHY LA English DT Article ID NONLINEAR CHROMATOGRAPHY; LIQUID-CHROMATOGRAPHY; COMPUTER-SIMULATION; BAND; OPTIMIZATION; PROPAGATION; SEPARATION AB Using the semi-ideal model, chromatograms were calculated for the separation of a binary mixture on a given column by displacement and elution chromatography. The optimum conditions for the maximum production rate with or without a recovery yield constraint were determined using the simplex algorithm. Mixtures of relative retention 1.20 and 1.70 and relative composition 1:3 and 3:1 were considered. The maximum production rates achieved in both modes of chromatography are close. In all instances studied the ratio of the production rates of the two modes was between 0.5 and 2. Without a yield constraint, for the cases studied the recovery yield achieved in overloaded elution is much higher than that achieved in displacement chromatography. However, the concentration of the fraction collected in the displacement mode is one to two orders of magnitude higher than that of the fraction collected in the elution mode. The choice between the modes of operation will depend largely on the comparative economics of displacer recovery and fraction concentrations. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. UNIV TENNESSEE,DEPT CHEM ENGN,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 26 TC 23 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD MAR 1 PY 1991 VL 540 IS 1-2 BP 1 EP 20 DI 10.1016/S0021-9673(01)88795-1 PG 20 WC Chemistry, Analytical SC Chemistry GA FB799 UT WOS:A1991FB79900001 ER PT J AU GROTCH, SL MACCRACKEN, MC AF GROTCH, SL MACCRACKEN, MC TI THE USE OF GENERAL-CIRCULATION MODELS TO PREDICT REGIONAL CLIMATIC-CHANGE SO JOURNAL OF CLIMATE LA English DT Article AB Equilibrium simulations using the best-available general circulation models to estimate the sensitivity of the climate to a doubling of the atmospheric carbon dioxide concentration are in broad general agreement that the global annual average surface air temperature would increase 2.5 to 4.5 K. However, at finer spatial scales, the range of changes in temperature and precipitation predicted by different computer models is much broader. Many shortcomings are also apparent in the model simulations of the present climate, indicating that further model improvements are needed to achieve reliable regional and seasonal projections of the future climatic conditions. RP GROTCH, SL (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ATMOSPHER & GEOPHYS SCI,MAIL STOP L-264,POB 808,LIVERMORE,CA 94550, USA. NR 0 TC 211 Z9 223 U1 2 U2 15 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR PY 1991 VL 4 IS 3 BP 286 EP 303 DI 10.1175/1520-0442(1991)004<0286:TUOGCM>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FG790 UT WOS:A1991FG79000002 ER PT J AU LIM, KH SMITH, DH AF LIM, KH SMITH, DH TI EXPERIMENTAL TEST OF CATASTROPHE-THEORY IN POLAR COORDINATES - EMULSION INVERSION FOR THE ETHANOL BENZENE WATER-SYSTEM SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article C1 US DOE,MORGANTOWN ENERGY TECHNOL CTR,MORGANTOWN,WV 26507. NR 24 TC 17 Z9 17 U1 0 U2 1 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 MAR 1 PY 1991 VL 142 IS 1 BP 278 EP 290 DI 10.1016/0021-9797(91)90057-F PG 13 WC Chemistry, Physical SC Chemistry GA EY284 UT WOS:A1991EY28400029 ER PT J AU FRIEDMAN, A AUERBACH, SP AF FRIEDMAN, A AUERBACH, SP TI NUMERICALLY INDUCED STOCHASTICITY SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article C1 SCI APPLICAT INT CORP,EMERYVILLE,CA 94608. RP FRIEDMAN, A (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 10 TC 15 Z9 15 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 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAR PY 1991 VL 93 IS 1 BP 171 EP 188 DI 10.1016/0021-9991(91)90078-Y PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FE379 UT WOS:A1991FE37900005 ER PT J AU AUERBACH, SP FRIEDMAN, A AF AUERBACH, SP FRIEDMAN, A TI LONG-TIME BEHAVIOR OF NUMERICALLY COMPUTED ORBITS - SMALL AND INTERMEDIATE TIMESTEP ANALYSIS OF ONE-DIMENSIONAL SYSTEMS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP AUERBACH, SP (reprint author), SCI APPLICAT INT CORP,2200 POWELL ST,SUITE 715,EMERYVILLE,CA 94608, USA. NR 11 TC 26 Z9 26 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAR PY 1991 VL 93 IS 1 BP 189 EP 223 DI 10.1016/0021-9991(91)90079-Z PG 35 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FE379 UT WOS:A1991FE37900006 ER PT J AU SPANGLER, BD WESTBROOK, EM AF SPANGLER, BD WESTBROOK, EM TI ISOLATION OF ISOELECTRICALLY PURE CHOLERA-TOXIN FOR CRYSTALLIZATION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID B-SUBUNIT; ADP-RIBOSYLATION; GANGLIOSIDE GM1; VIBRIO-CHOLERAE; PROTEINS; CRYSTALS; PURIFICATION; RESOLUTION AB We have determined that the failure of cholera toxin to crystallize well results from its isoelectric heterogeneity, which is probably due to a post-translational process such as deamidation of its B subunit. Every sample of cholera toxin we have examined from commercial or academic suppliers has been heterogeneous; heterogeneous cholera toxin does not crystallize satisfactorily. We have overcome this problem by using ion-exchange fast protein liquid chromatography (FPLC) to obtain an isoelectrically homogeneous species of cholera toxin. Homogeneous cholera toxin crystallizes readily, forming single, nonmosaic crystals suitable for X-ray diffraction studies. For this process, protein was applied to a MonoQ ion-exchange column, then eluted with an isocratic low salt buffer followed by a linear salt gradient (0-100 mM NaCl). Column fractions were analyzed on isoelectric focusing gels, and those fractions containing the desired homogeneous species were pooled and concentrated. Crystals formed within 24 to 48 h in a MOPS/PEG buffer, which made use of slow isoelectric precipitation to induce crystallization. RP SPANGLER, BD (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. OI Spangler, Brenda/0000-0001-6093-7469 NR 26 TC 3 Z9 3 U1 0 U2 0 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 MAR PY 1991 VL 110 IS 1-2 BP 220 EP 227 DI 10.1016/0022-0248(91)90889-D PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FF694 UT WOS:A1991FF69400031 ER PT J AU LOGRASSO, TA SCHMIDT, FA AF LOGRASSO, TA SCHMIDT, FA TI SOLID-STATE CRYSTAL-GROWTH OF REFRACTORY-METALS BY ARC-ZONE MELTING SO JOURNAL OF CRYSTAL GROWTH LA English DT Article AB Crystal growth by the arc-zone melting technique has been used over the past 25 years to prepare single crystals of the refractory metals and their alloys. During arc-zone melting only the upper surface of the metal is melted yet the entire cross section of the rod becomes single crystalline. The mechanism for growth of single crystals by this technique is not understood and a process parameter study was conducted to determine the operating mechanisms of crystal growth. It was found that crystal growth occurs in the solid state and is a result of large scale grain boundary migration. A minimum power input to the arc was required to prepare crystals and this was related to minimum temperature necessary for boundary migration. A series of quenching experiments indicates that boundary migration is driven by abnormal grain growth processes and is independent of the initial microstructure of the metal. The length and size of crystals prepared are determined by the number and frequency of boundary intersections with the advancing molten pool. There was no preferred orientation observed for the crystals prepared. RP LOGRASSO, TA (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 14 TC 4 Z9 4 U1 1 U2 3 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 MAR PY 1991 VL 110 IS 3 BP 363 EP 372 DI 10.1016/0022-0248(91)90272-7 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FF965 UT WOS:A1991FF96500004 ER PT J AU BOURRET, ED MERK, EC AF BOURRET, ED MERK, EC TI EFFECTS OF TOTAL LIQUID ENCAPSULATION ON THE CHARACTERISTICS OF GAAS SINGLE-CRYSTALS GROWN BY THE VERTICAL GRADIENT FREEZE TECHNIQUE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID SEMI-INSULATING GAAS; SI-IMPLANTED GAAS; CZOCHRALSKI GAAS; STOICHIOMETRY; CARBON AB Total liquid encapsulation with B2O3 has been used to grow 50 mm diameter GaAs single crystals in PBN crucibles in a vertical gradient freeze configuration. The B2O3 layer efficiently prevents direct contact between the crucible and the GaAs charge and reproducible growth of single crystals can be achieved. The effect of B2O3 water content on the structural and electrical characteristics of the crystals was investigated. Water vapor can be trapped between the crystal and the crucible affecting the surface morphology of the crystals. The water content of the B2O3 encapsulant was found to affect the electrical properties of the crystals in a manner similar to what is observed for growth of GaAs crystals by the liquid encapsulated czochralski technique. Crystals grown encapsulated with dry B2O3 have been ion-implanted with silicon. The implant activations are comparable to those obtained on LEC grown crystals. Total liquid encapsulation in vertical gradient freeze can be used to produce device quality substrates. RP BOURRET, ED (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720, USA. NR 17 TC 17 Z9 18 U1 1 U2 2 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 MAR PY 1991 VL 110 IS 3 BP 395 EP 404 DI 10.1016/0022-0248(91)90275-A PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FF965 UT WOS:A1991FF96500007 ER PT J AU TSAO, JY AF TSAO, JY TI PHASE-EQUILIBRIA DURING INSB MOLECULAR-BEAM EPITAXY SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID GROWTH; SUPERLATTICES; INAS1-XSBX; RANGE AB We analyze the thermodynamic equilibria between the solid, liquid and vapor phases of the In-Sb system. From this analysis, we deduce the "window" in pressure and temperature within which molecular beam epitaxy of the InSb zincblende compound is thermodynamically preferred over condensation of other phases. Our method of analysis should be generally applicable to other III-V systems as well. RP TSAO, JY (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 22 TC 13 Z9 13 U1 0 U2 2 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 MAR PY 1991 VL 110 IS 3 BP 595 EP 603 DI 10.1016/0022-0248(91)90297-I PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FF965 UT WOS:A1991FF96500029 ER PT J AU LARABELL, C CHANDLER, DE AF LARABELL, C CHANDLER, DE TI FERTILIZATION-INDUCED CHANGES IN THE VITELLINE ENVELOPE OF ECHINODERM AND AMPHIBIAN EGGS - SELF-ASSEMBLY OF AN EXTRACELLULAR-MATRIX SO JOURNAL OF ELECTRON MICROSCOPY TECHNIQUE LA English DT Review DE SEA URCHIN EGG; XENOPUS-LAEVIS EGG; QUICK FREEZING ID SEA-URCHIN EGGS; XENOPUS-LAEVIS EGGS; RESPIRATORY BURST OXIDASE; ARBACIA-PUNCTULATA EGGS; CORTICAL GRANULES; STRONGYLOCENTROTUS-PURPURATUS; SPERM RECEPTOR; HYALINE LAYER; JELLY COAT; IMMUNOCYTOCHEMICAL LOCALIZATION AB The surface of the unfertilized sea urchin egg is covered by the vitelline layer (VL), a fibrous extracellular matrix that contains receptors for sperm. At fertilization, cortical granule exocytosis releases enzymes and structural proteins that cause the VL to elevate and become remodelled into the mechanically and chemically tough fertilization envelope. This envelope prevents further penetration of sperm and protects the embryo during early development. A thicker, more complex vitelline envelope surrounds the Xenopus laevis egg. This fibrous coat is also restructured at fertilization to produce an impenetrable barrier to to sperm. The biochemical steps that occur during self-assembly of these fertilization envelopes are reviewed, and the ultrastructural changes that occur, as seen in platinum replicas of quick-frozen, deep-etched, and rotary-shadowed eggs, are illustrated. C1 ARIZONA STATE UNIV,DEPT ZOOL,TEMPE,AZ 85287. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. FU NICHD NIH HHS [HD00619] NR 111 TC 39 Z9 39 U1 0 U2 4 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0741-0581 J9 J ELECTRON MICR TECH PD MAR PY 1991 VL 17 IS 3 BP 294 EP 318 DI 10.1002/jemt.1060170305 PG 25 WC Biology; Microscopy SC Life Sciences & Biomedicine - Other Topics; Microscopy GA EX293 UT WOS:A1991EX29300004 PM 2045963 ER PT J AU HENDERSON, LF COLELLA, P PUCKETT, EG AF HENDERSON, LF COLELLA, P PUCKETT, EG TI ON THE REFRACTION OF SHOCK-WAVES AT A SLOW FAST GAS INTERFACE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID NON-UNIFORM MEDIA AB We present the results of numerical computations of the refraction of a plane shock wave at a CO2/CH4 gas interface. The numerical method was an operator split version of a second-order Godunov method, with adaptive grid refinement. We solved the unsteady, two-dimensional, compressible, Euler equations numerically, assuming perfect gas equations of state, and compared our results with the experiments of Abd-El-Fattah & Henderson. Good agreement was usually obtained, especially when the contamination of the CH4 by the CO2 was taken into account. Remaining discrepancies were ascribed to the uncertainties in measuring certain wave angles, due to sharp curvature, poor definition, or short length of the waves at large angles of incidence. All the main features of the regular and irregular refractions were resolved numerically for shock strengths that were weak, intermediate, or strong. These include free precursor shock waves in the intermediate and strong cases, evanescent (smeared out) compressions in the weak case, and the appearance of an extra expansion wave in the bound precursor refraction (BPR). The structure of a BPR was elucidated for the first time. C1 UNIV CALIF BERKELEY,DEPT MECH ENGN,BERKELEY,CA 94720. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. UNIV CALIF DAVIS,DEPT MATH,DAVIS,CA 95615. RP HENDERSON, LF (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 21 TC 51 Z9 52 U1 0 U2 3 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 MAR PY 1991 VL 224 BP 1 EP & DI 10.1017/S0022112091001623 PG 0 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA FG991 UT WOS:A1991FG99100001 ER PT J AU CONCUS, P FINN, R AF CONCUS, P FINN, R TI EXOTIC CONTAINERS FOR CAPILLARY SURFACES SO JOURNAL OF FLUID MECHANICS LA English DT Article AB In this paper we discuss 'exotic' rotationally symmetric containers that admit an entire continuum of distinct equilibrium capillary free surfaces. The paper extends earlier work to a larger class of parameters and clarifies and simplifies the governing differential equations, while expressing them in a parametric form appropriate for numerical integration. A unified presentation suitable for both zero and non-zero gravity is given. Solutions for the container shapes are depicted graphically along with members of the free-surface continuum, and comments are given concerning possible physical experiments. C1 UNIV CALIF BERKELEY,DEPT MATH,BERKELEY,CA 94720. STANFORD UNIV,DEPT MATH,STANFORD,CA 94305. RP CONCUS, P (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 6 TC 6 Z9 6 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 MAR PY 1991 VL 224 BP 383 EP 394 DI 10.1017/S0022112091001805 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA FG991 UT WOS:A1991FG99100019 ER PT J AU KOKJOHN, TA SAYLER, GS MILLER, RV AF KOKJOHN, TA SAYLER, GS MILLER, RV TI ATTACHMENT AND REPLICATION OF PSEUDOMONAS-AERUGINOSA BACTERIOPHAGES UNDER CONDITIONS SIMULATING AQUATIC ENVIRONMENTS SO JOURNAL OF GENERAL MICROBIOLOGY LA English DT Article ID TRANSDUCTION; BACTERIA; DENSITY AB Bacterial viruses are important in regulating bacterial population densities in natural aquatic environments, but the dynamics of bacteriophage-bacterial interactions in nature are poorly understood. In this study, the attachment and replication of three Pseudomonas aeruginosa bacteriophages (one temperate and two virulent) were investigated under conditions similar to those found in nature. Attachment and replication of bacteriophages were not impaired at host-cell densities equal to or lower ( < 10(5) c.f.u. ml-1) than those frequently found in aquatic environments when the host cells were physiologically competent to allow phage growth. Attachment (45-93%) to either actively growing or starved cells was not impaired in river water, indicating that attachment is efficient in natural freshwater habitats. However, the replication of bacteriophages was significantly altered in starved cells in river water: the latency period was extended (broth, 70-110 min; river water, 110-240 min), and the burst size was reduced (broth, 27-65; river water 5-7). The findings of this study indicate that phages are likely to affect microbial ecology significantly in freshwater ecosystems. C1 LOYOLA UNIV,STRITCH SCH MED,DEPT MOLEC & CELLULAR BIOCHEM,MAYWOOD,IL 60153. UNIV TENNESSEE,DEPT MICROBIOL,KNOXVILLE,TN 37932. UNIV TENNESSEE,CTR ENVIRONM BIOTECHNOL,GRAD PROGRAM ECOL,KNOXVILLE,TN 37932. RP KOKJOHN, TA (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439, USA. NR 24 TC 72 Z9 73 U1 1 U2 4 PU SOC GENERAL MICROBIOLOGY PI READING PA HARVEST HOUSE 62 LONDON ROAD, READING, BERKS, ENGLAND RG1 5AS SN 0022-1287 J9 J GEN MICROBIOL JI J. Gen. Microbiol. PD MAR PY 1991 VL 137 BP 661 EP 666 PN 3 PG 6 WC Microbiology SC Microbiology GA FC100 UT WOS:A1991FC10000027 ER PT J AU BIRN, J HONES, EW CRAVEN, JD FRANK, LA ELPHINSTONE, RD STERN, DP AF BIRN, J HONES, EW CRAVEN, JD FRANK, LA ELPHINSTONE, RD STERN, DP TI ON OPEN AND CLOSED FIELD LINE REGIONS IN TSYGANENKO FIELD MODEL AND THEIR POSSIBLE ASSOCIATIONS WITH HORSE COLLAR AURORAS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLANETARY MAGNETIC-FIELD; POLAR-CAP; GEOMAGNETIC-FIELD; CURRENT SYSTEM; ISEE-3; TAIL; PATTERN; TIMES; SHEET; ARCS AB Using the empirical Tsyganenko (1987) long model as a prime example of a magnetospheric field model, we have attempted to identify the boundary between open and closed field lines. We define as "closed" all field lines that are connected with the Earth at both ends and cross the equatorial plane earthward of x = -70R(E), the tailward validity limit of the Tsyganenko model. We find that the form of the open/closed boundary at the Earth's surface, identified with the polar cap boundary, can exhibit the arrowhead shape, pointed toward the Sun, observed in "horse collar auroras" (Hones et al., 1989). The "polar cap" size in the Tsyganenko model increases with increasing K(p) values, and it becomes rounder and less pointed. The superposition of a net B(y) field, which is the expected consequence of an IMF B(y), rotates the polar cap pattern and, for larger values, degrades the arrowhead shape, resulting in polar cap configurations consistent with known asymmetries in the aurora. The pointedness of the polar cap shape also diminishes or even completely disappears if the low-latitude magnetopause is assumed open and located considerably inside of the outermost magnetic flux surface in the Tsyganenko model. The arrowhead shape of the polar cap is found to be associated with a strong increase of B(z) from midnight toward the tail flanks, which is observed independently, and is possibly related to the NBZ field-aligned current system, observed during quiet times and strongly northward IMF B(z). The larger B(z) values near the flanks of the tail cause more magnetic flux to close through these regions than through the midnight equatorial region. Since field lines at the flanks primarily map to the dayside polar regions, it becomes plausible that the closed field line region extends to higher latitudes on the dayside than on the nightside, when the increase of B(z) becomes more pronounced. By comparison with a different field model we demonstrate that this association is not unique to the Tsyganenko model. The similarity of the quiet symmetric polar cap pattern to "horse collar" auroras suggests that the bright "bars," observed at the sides of the arrowhead shaped polar cap, are connected with the separatrix layers (or plasma sheet boundary layers) extending to the distant X line or separator, while the adjacent "web" regions, located between the bars and the main auroral oval, are connected with the low-latitude boundary regions along the flanks of the magnetotail. C1 UNIV IOWA,IOWA CITY,IA 52242. UNIV CALGARY,CALGARY T2N 1N4,ALBERTA,CANADA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BIRN, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 28 TC 31 Z9 31 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1991 VL 96 IS A3 BP 3811 EP 3817 DI 10.1029/90JA02124 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FA247 UT WOS:A1991FA24700033 ER PT J AU WILSON, GV JARDINE, PM LUXMOORE, RJ ZELAZNY, LW LIETZKE, DA TODD, DE AF WILSON, GV JARDINE, PM LUXMOORE, RJ ZELAZNY, LW LIETZKE, DA TODD, DE TI HYDROGEOCHEMICAL PROCESSES CONTROLLING SUBSURFACE TRANSPORT FROM AN UPPER SUBCATCHMENT OF WALKER BRANCH WATERSHED DURING STORM EVENTS .1. HYDROLOGIC TRANSPORT PROCESSES SO JOURNAL OF HYDROLOGY LA English DT Article ID HUMID HEADWATER CATCHMENTS; 2 FORESTED WATERSHEDS; RAINFALL INTENSITY; RUNOFF GENERATION; CAPILLARY-FRINGE; FLOW; MACROPOROSITY; MESOPOROSITY; LAND; SOIL AB Concerns over the effects of acid rain have stimulated numerous hydrometric and geochemical studies on forested watersheds with an emphasis on stream water chemistry. However, integrated studies are seriously lacking, and inferences of soil hydrogeochemical processes from periodic stream water chemistry may be grossly misleading. A small forested subcatchment was intensively instrumented for hydrologic and chemical analyses to improve our understanding of the processes that control subsurface transport of solutes. The timing and volume of subsurface flows were found to be highly dependent upon soil hydromorphologic properties. Development of perched water tables was the predominate mechanism of subsurface flow through the lower layers during moderate to high flow events. Perching of water was insignificant during low flow events and only partially responsible for lateral flow through the upper soil layers during moderate events. The importance of nonequilibrium conditions during even low flow events was illustrated by the occurrence of saturated flow through unsaturated (matric potentials < - 2 kPa) soil. The initial subsurface flow response of a moderate and high flow event was predominately (> 70%) new water that bypassed the soil matrix. As flows continued the percentage of old water increased. Intermittent rainfall during the high flow event caused multiple peaks in subsurface flow with subtle increases in perching. These hydrograph peaks were associated with decreases in the percentage of old water. This suggests an increase in the portion of infiltrating water that bypasses soil matrix water via macropores causing increases in subsurface flows with limited growth of perched water tables. The persistence of perched water tables as flow decreased was consistently observed. Decreases in solute concentrations causing decreases in conductivity of pores was inferred as one mechanism for this. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. LIETZKE SOIL SERV,RUTLEDGE,TN 37861. RP WILSON, GV (reprint author), UNIV TENNESSEE,POB 1071,KNOXVILLE,TN 37901, USA. NR 24 TC 57 Z9 59 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD MAR PY 1991 VL 123 IS 3-4 BP 297 EP 316 DI 10.1016/0022-1694(91)90096-Z PG 20 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA FD572 UT WOS:A1991FD57200006 ER PT J AU WILSON, GV JARDINE, PM LUXMOORE, RJ ZELAZNY, LW TODD, DE LIETZKE, DA AF WILSON, GV JARDINE, PM LUXMOORE, RJ ZELAZNY, LW TODD, DE LIETZKE, DA TI HYDROGEOCHEMICAL PROCESSES CONTROLLING SUBSURFACE TRANSPORT FROM AN UPPER SUBCATCHMENT OF WALKER BRANCH WATERSHED DURING STORM EVENTS .2. SOLUTE TRANSPORT PROCESSES SO JOURNAL OF HYDROLOGY LA English DT Article ID 2 CONTRASTING WATERSHEDS; SOIL; ALUMINUM; MACROPOROSITY; MANGANESE; FORESTS; SULFATE; CARBON; IRON; FLOW AB Geochemical studies of transport from watersheds to date have focused on stream chemistry and/or soil lysimeter data to interpret soil processes. Direct measurements of subsurface transport of solutes from hillslopes during storm events and integration with hydrometric analyses is seriously lacking. This study presents subsurface transport of solutes (K, Ca, Mg, Mn, Fe, Al, Na, SO4, and Si) from a 0.47-ha hillslope subcatchment at the uppermost reach of the west fork of Walker Branch watershed for six storm events. Transport of Fe and Al was primarily (> 55%) as suspended particles > 0.4-mu-m which resulted in a very rapid increase in their concentrations at the initiation of subsurface flow. Weathering via particle detachment (i.e. suspended particles) was believed to be due to rapid infiltration of new water of low ionic strength which increases the diffuse double layer facilitating detachment of particles. The concentration of Fe and Al in filtered solutions (< 0.4-mu-m) increased as flow increased and decreased during the recession limb of the hydrograph. The mechanisms for the increase then decrease is believed to be electrostatic exchange from surfaces of conducting pores followed by a kinetically controlled release via mineral decomposition. The most commonly observed solute transport pattern during storm events was an increase in concentration as flow rate increased, followed by a decrease in concentration during the recession limb of the hydrograph. This response was due to flushing of solutes primarily from water-filled mesopores with macropores serving as conduits for solutes with limited attenuation. Soil matrix pores (> 6-mu-m diameter) exhibited an unlimited supply of solutes for transport through larger pores in that soil solution concentrations showed no depletion of elements during storm events. A mass balance of solutes was computed for the subcatchment for 1988, and subsurface storm flow through the upper soil profile (< 3 m) resulted in only a minor export of deposited solutes. However, subsurface saturated flow during individual storms were shown to be significant exporters of nutrients. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. LIETZKE SOIL SERV,RUTLEDGE,TN 37861. RP WILSON, GV (reprint author), UNIV TENNESSEE,POB 1071,KNOXVILLE,TN 37901, USA. NR 30 TC 34 Z9 36 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD MAR PY 1991 VL 123 IS 3-4 BP 317 EP 336 DI 10.1016/0022-1694(91)90097-2 PG 20 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA FD572 UT WOS:A1991FD57200007 ER PT J AU SPANGLER, BD AF SPANGLER, BD TI BINDING TO NATIVE PROTEINS BY ANTIPEPTIDE MONOCLONAL-ANTIBODIES SO JOURNAL OF IMMUNOLOGY LA English DT Article ID CHOLERA-TOXIN; SYNTHETIC PEPTIDE; B-SUBUNIT; INDUCTION AB mAb raised against synthetic peptides derived from cholera toxin, myohemerythrin, and sickle hemoglobin were analyzed by both solid-phase and solution-phase methods. Antipeptide mAb against cholera toxin (mAb TE32 and TE33), against myohemerythrin (mAb B13I2, B13C2, and B13F2), and against sickle hemoglobin (mAb HuS-1 and HuS-2), had been previously described and used for vaccine development, structural characterization, or identification of a specific antigenic determinant, and each was apparently capable of binding both peptide and native Ag. In this study, all were found to bind whole protein when tested against immobilized Ag in a standard solid-phase assay (ELISA), yet none of the antibodies recognized the Ag in its true native form, failing to bind when tested in several solution-phase assay systems, including size exclusion HPLC. This discrepancy may be the result of modifications of the epitope created by interaction and possible denaturation of the protein on the solid-phase matrix. As a consequence, binding of these antibodies to peptides, either immobilized or in solution, or to immobilized protein, cannot be used to infer that the peptide has assumed a conformation that corresponds to that of the cognate sequence in the native protein. A re-evaluation of binding data that relates antipeptide mAb to native structural characteristics may be necessary. RP SPANGLER, BD (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. OI Spangler, Brenda/0000-0001-6093-7469 NR 41 TC 68 Z9 70 U1 0 U2 1 PU AMER ASSOC IMMUNOLOGISTS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0022-1767 J9 J IMMUNOL JI J. Immunol. PD MAR 1 PY 1991 VL 146 IS 5 BP 1591 EP 1595 PG 5 WC Immunology SC Immunology GA EY684 UT WOS:A1991EY68400031 PM 1993848 ER PT J AU LI, C FREEMAN, AJ FU, CL AF LI, C FREEMAN, AJ FU, CL TI ELECTRONIC-STRUCTURE AND MAGNETIC-PROPERTIES OF THE HCP CO(0001) SURFACE SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article ID EXCHANGE; COBALT; FERROMAGNETISM; MOLECULES; FILMS; LAYER; CU AB Results of a spin polarized full potential linearized augmented plane wave (FLAPW) study of the hcp Co(0001) surface is reported. The calculated surface magnetic moment (almost-equal-to 1.76-mu-B) is enhanced by almost-equal-to 7% from the calculated bulk value (almost-equal-to 1.64-mu-B) and by almost-equal-to 9% from the experimental bulk value (almost-equal-to 1.57-mu-B), a result of the narrowing of the 3d electron bands at the surface. In this system, the surface effect is seen to extend into the second atomic layer below the surface, in contrast with the one layer range found for the non-close-packed cobalt surfaces (e.g., bcc or fcc (001)). As estimated from the total energy calculations, the surface energy of hcp Co(0001) is almost-equal-to 2 J/m2. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. RP LI, C (reprint author), NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. NR 22 TC 22 Z9 22 U1 0 U2 1 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 MAR PY 1991 VL 94 IS 1-2 BP 134 EP 140 DI 10.1016/0304-8853(91)90122-Q PG 7 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA FE810 UT WOS:A1991FE81000021 ER PT J AU KORDAS, G MOORE, GA JORGENSEN, JD ROTELLA, F HITTERMAN, RL VOLIN, KJ FABER, J AF KORDAS, G MOORE, GA JORGENSEN, JD ROTELLA, F HITTERMAN, RL VOLIN, KJ FABER, J TI STRUCTURE EVOLUTION DURING THERMAL-PROCESSING OF HIGH-TC CERAMIC SUPERCONDUCTORS PRODUCED USING SOL-GEL TECHNIQUES SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article DE SOL GEL PROCESSING; Y-BA-CU-O SYSTEM; NEUTRON DIFFRACTION; SUPERCONDUCTIVITY ID ORGANOMETALLIC ROUTE; PHASE; BA2YCU3O7-DELTA; YBA2CU3O7-DELTA; SYSTEM AB Characterization of the decomposition and phase development reactions for Cu(II) methoxyethoxide, 2Ba-3Cu, Y-3Cu, and Y-2Ba-3Cu gels has been performed using in situ neutron diffraction and differential thermal analysis (DTA). The structural evolution process of a Y-2Ba-3Cu gel to the superconducting YBa2Cu3O7-x phase was elucidated using the acquired spectra. Precursor gel powder was produced from an alkoxide sol-gel system having a methoxyethanol, methyl ethyl ketone and toluene solvent mixture. Neutron diffraction results indicate initial YBa2Cu3O7-x formation below 700-degrees-C, and that a firing temperature of 850-degrees-C is sufficient to produce essentially single-phase YBa2Cu3O7-x. The conversion of BaCO3 to BaCO3 polymorph was observed to occur between 790 and 800-degrees-C, after which rapid formation of the YBa2Cu3O7-x tetragonal phase occurred. The results also indicate an incomplete conversion of the non-superconducting tetragonal phase to the superconducting orthorhombic phase during the cool-down and annealing segments of the heat treatment. C1 UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801. UNIV ILLINOIS,SCI & TECHNOL CTR SUPERCONDUCT,DIV CERAM,DEPT MAT SCI,URBANA,IL 61801. AMOCO CORP,NAPERVILLE,IL 60566. ARGONNE NATL LAB,ARGONNE,IL 60439. NR 19 TC 11 Z9 12 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD MAR PY 1991 VL 1 IS 2 BP 175 EP 180 DI 10.1039/jm9910100175 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FH863 UT WOS:A1991FH86300004 ER PT J AU KORDAS, G MOORE, GA SALAMON, MB HAYTER, JB AF KORDAS, G MOORE, GA SALAMON, MB HAYTER, JB TI ROLE OF FRACTAL STRUCTURE ON THIN-FILM PROCESSING OF YBA2CU3O7-X USING ALKOXIDE SOLS SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article DE OXIDE SUPERCONDUCTOR; FRACTAL; SOL GEL PROCESSING; THIN FILM ID SUPERCONDUCTOR; ROUTE AB An alkoxide sol-gel route has been developed for producing YBa2Cu3O7-x superconducting powder and oriented thin films. Cu(II) methoxyethoxide, Y methoxyethoxide and Ba methoxyethoxide precursors were synthesized and processed into stable sols with methoxyethanol (MOE), methyl ethyl ketone (MEK), toluene and diisopropyl ketone (DIK) solvents. Pyridine (C5H5N), lutidine (C13H21N) and toluene-2,4-disulphonic acid were used as organic additives to modify the polymeric network structure and corresponding sol behaviour. Small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) were used to study the structural modifications in sols and gels with changes in solution chemistry parameters, viz. acidity/basicity, moisture exposure and solvent system. Mass-fractal dimensions in the range 2.0-2.5 were obtained for 0.01-0.1 mol kg-1 YBa2Cu3 sols in methoxyethanol-methyl ethyl ketone-toluene solvent. Significant effects of two organic base additives, pyridine and lutidine, on the sol structure were observed as a function of sol concentration. The ability of the different solutions to cover SrTiO3, ZrO2, sapphire, SiO2 and silicon substrates was measured by contact-angle measurements. Thin films produced via spin casting, dip coating and spray coating were characterized using optical, scanning electron microscopy (SEM) and X-ray diffraction techniques, and the results are discussed in terms of the sol structures. C1 UNIV ILLINOIS,SCI & TECHNOL CTR SUPERCONDUCT,URBANA,IL 61801. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. RP KORDAS, G (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,DIV CERAM,MAT RES LAB,105 S GOODWIN,URBANA,IL 61801, USA. NR 28 TC 5 Z9 5 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD MAR PY 1991 VL 1 IS 2 BP 181 EP 189 DI 10.1039/jm9910100181 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FH863 UT WOS:A1991FH86300005 ER PT J AU BLAU, PJ AF BLAU, PJ TI RUNNING-IN - ART OR ENGINEERING SO JOURNAL OF MATERIALS ENGINEERING LA English DT Article AB Running-in is an initial surface and subsurface conditioning process that often occurs when sliding or rolling contact is established between two solid bodies. This article first addresses and defines the nature of running-in as it relates to steady-state sliding conditions. Running in procedures are not always given the type of systematic analysis that goes into other forms of friction and wear testing, but are often developed by trial and error. Studies of running-in are relatively rare in the literature of tribology, and they often appear with only passing mention. The concept of a running-in (break-in) map is explored. Examples of the analysis of friction traces show how they can be used systematically to study the running-in process. Running-in is found to be a property not only of the materials in contact, but also of the system in which they reside. RP BLAU, PJ (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 0 TC 9 Z9 9 U1 2 U2 7 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 0931-7058 J9 J MATER ENG PD MAR PY 1991 VL 13 IS 1 BP 47 EP 53 DI 10.1007/BF02834123 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA FA921 UT WOS:A1991FA92100005 ER PT J AU WEIDLICH, G GOELZ, M WANG, R EVENSON, WE GARDNER, JA KESZLER, DA SOMMERS, JA OSTENSON, JE AF WEIDLICH, G GOELZ, M WANG, R EVENSON, WE GARDNER, JA KESZLER, DA SOMMERS, JA OSTENSON, JE TI STRUCTURAL AND ELECTRONIC-PROPERTIES OF INDIUM-DOPED YBA2CU3O-SIGMA SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB We have measured x-ray diffraction patterns and Meissner flux exclusion of YBa2Cu3O-delta containing indium. All samples were synthesized at temperatures near 940-degrees-C, and the data indicate the indium atomic solubility to be approximately 3% per formula unit. At the solubility limit T(c) is reduced from 92.7 K to 91.3 K relative to undoped samples, and the total magnetic flux excluded is reduced from approximately 40% to about 10%. For samples of formula In(x)Y1-xBa2Cu3O-delta concentrations of other Y-Ba-Cu oxide phases are low and do not depend systematically on x. These results indicate that indium substitutes predominantly for yttrium when x is small. C1 OREGON STATE UNIV,CTR ADV MAT RES,CORVALLIS,OR 97331. OREGON STATE UNIV,DEPT CHEM,CORVALLIS,OR 97331. TELEDYNE WAH CHANG CORP,ALBANY,OR 97321. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP WEIDLICH, G (reprint author), OREGON STATE UNIV,DEPT PHYS,CORVALLIS,OR 97331, USA. NR 5 TC 5 Z9 5 U1 1 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 MAR PY 1991 VL 6 IS 3 BP 446 EP 449 DI 10.1557/JMR.1991.0446 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA FA769 UT WOS:A1991FA76900002 ER PT J AU SHOEMAKER, JR LUTTON, RT WESLEY, D WHARTON, WR OEHRLI, ML HERTE, MS SABOCHICK, MJ AF SHOEMAKER, JR LUTTON, RT WESLEY, D WHARTON, WR OEHRLI, ML HERTE, MS SABOCHICK, MJ TI POINT-DEFECT STUDY OF CUTI AND CUTI2 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AMORPHIZATION; IRRADIATION; MIGRATION; ALLOY; VACANCIES; ENERGIES; RECOVERY; COPPER; METALS AB The energies and configurations of interstitials and vacancies in the ordered compounds CuTi and CuTi2 were determined using atomistic simulation with realistic embedded-atom potentials. The formation energy of an antisite pair was found to be 0.385 and 0.460 eV in CuTi and CuTi2, respectively. In both compounds, the creation of a vacancy by the removal of either a Cu or Ti atom resulted in a vacant Cu site, with an adjacent antisite defect in the case of the Ti vacancy. The vacant Cu site in CuTi was found to be very mobile within two adjacent (001) Cu planes, with a migration energy of 0.19 eV, giving rise to two-dimensional migration. The vacancy migration energy across (001) Ti planes, however, was 1.32 eV, which could be lowered to 0.75 or 0.60 eV if one or two Cu antisite defects were initially present in these planes. In CuTi2, the vacancy migration energy of 0.92 eV along the (001) Cu plane was significantly higher than in CuTi. The effective vacancy formation energies were calculated to be 1.09 eV and 0.90 eV in CuTi and CuTi2, respectively. Interstitials created by inserting either a Cu or Ti atom had complicated configurations in which a Cu <111> split interstitial was surrounded by two or three Ti antisite defects. The interstitial formation energy was estimated to be 1.7 eV in CuTi and 1.9 eV in CuTi2. C1 USAF,INST TECHNOL,DEPT ENGN PHYS,WRIGHT PATTERSON AFB,OH 45433. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NR 30 TC 14 Z9 14 U1 1 U2 5 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 MAR PY 1991 VL 6 IS 3 BP 473 EP 482 DI 10.1557/JMR.1991.0473 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA FA769 UT WOS:A1991FA76900007 ER PT J AU PRONNECKE, S CARO, A VICTORIA, M DELARUBIA, TD GUINAN, MW AF PRONNECKE, S CARO, A VICTORIA, M DELARUBIA, TD GUINAN, MW TI THE EFFECT OF ELECTRONIC-ENERGY LOSS ON THE DYNAMICS OF THERMAL SPIKES IN CU SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID EMBEDDED-ATOM-METHOD; DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; METALS; TEMPERATURE; RELAXATION; DENSITY; NI AB We present results of a molecular dynamics simulation study of the effect of electron-ion interactions on the dynamics of the thermal spike in Cu. Interatomic forces are described with a modified embedded atom method potential. We show that the electron-ion interaction acts to reduce the lifetime of the thermal spike and therefore the amount of atomic rearrangement that takes place in energetic displacement cascades in Cu. The results point toward the important effect that inelastic energy losses might have on the dynamics of displacement cascades in the subcascade energy regime where the lifetime of the thermal spike is expected to exceed the electron-phonon coupling time. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 31 TC 50 Z9 50 U1 3 U2 12 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 MAR PY 1991 VL 6 IS 3 BP 483 EP 491 DI 10.1557/JMR.1991.0483 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA FA769 UT WOS:A1991FA76900008 ER PT J AU DAHOTRE, NB MCCAY, MH MCCAY, TD GOPINATHAN, S ALLARD, LF AF DAHOTRE, NB MCCAY, MH MCCAY, TD GOPINATHAN, S ALLARD, LF TI PULSE LASER PROCESSING OF A SIC/AL-ALLOY METAL MATRIX COMPOSITE SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-CARBIDE; INTERFACIAL REACTIONS; ELECTRON-MICROSCOPY; ALUMINUM; MICROSTRUCTURE; FIBER; AL AB The microstructural changes and the tensile behavior of laser processed A356-Al alloy matrix composites reinforced with 10 and 20 vol. % SiC particulates are characterized. The autogenous bead-on-plate welds were made using a pulsed CO2 laser operating at a peak power level of 3.2 kW. The pulse on-time was constant at 20 ms and the off-time was varied from 20 to 2 ms (duty cycles of 50-91%). The microstructure of the laser melted region was investigated by optical, scanning, and transmission electron microscopy, and x-ray microchemical analysis techniques. The extent of microstructural changes varied directly with duty cycle, i.e., being a maximum for the longest (91%) duty cycles. Pulsed laser processing produced partial to complete dissolution of SiC particles and sometimes resulted in the formation of aluminum carbide. The associated rapid cooling also produced a fine distribution of nonequilibrium complex precipitates. In addition, the laser energy modified the SiC surface both physically and chemically. The results of tensile tests indicated that the modified SiC and the distribution of fine nonequilibrium precipitates enhance the mechanical properties of the laser processed composites. Optimum changes in microstructure and mechanical properties were obtained in the composites processed with intermediate (67 and 74%) duty cycles; therefore pulsed processing appears to be a strong candidate for successful joining of these MMCs. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831. RP DAHOTRE, NB (reprint author), UNIV TENNESSEE,INST SPACE,CTR LASER APPLICAT,TULLAHOMA,TN 37388, USA. NR 46 TC 23 Z9 23 U1 9 U2 20 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 MAR PY 1991 VL 6 IS 3 BP 514 EP 529 DI 10.1557/JMR.1991.0514 PG 16 WC Materials Science, Multidisciplinary SC Materials Science GA FA769 UT WOS:A1991FA76900012 ER PT J AU LEE, EH LEWIS, MB BLAU, PJ MANSUR, LK AF LEE, EH LEWIS, MB BLAU, PJ MANSUR, LK TI IMPROVED SURFACE-PROPERTIES OF POLYMER MATERIALS BY MULTIPLE ION-BEAM TREATMENT SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID RADIATION-CHEMISTRY; RAMAN-SCATTERING; CARBON-FILMS; IRRADIATION; GRAPHITE; ENERGY AB Ion beam treatment studies have been carried out to investigate the potential for improvements in surface-sensitive properties of polymers. Kapton, Teflon, Tefzel, and Mylar have been implanted with boron, nitrogen, carbon, silicon, and iron ions, singly or simultaneously with dual or triple beams. The implanted materials were characterized by optical microscopy, transmission electron microscopy, nano-hardness indentation, wear testing, scanning tunneling microscopy, x-ray analysis, nuclear reaction analysis, Fourier transform infrared spectroscopy, and Raman spectroscopy. Although the polymers showed a color change and varying degrees of measurable surface depression in the bombarded area, the implanted surface revealed substantial improvements in surface smoothness, hardness, and wear resistance. In particular, B,N,C triple-beam implanted Kapton showed over 30 times larger hardness than unimplanted material, making it more than three times harder than stainless steel. Sliding wear properties were characterized using an oscillating nylon or high carbon steel wear ball. Severe wear tracks were observed in virgin Kapton, but no appreciable wear was observed in ion implanted Kapton. Mechanisms underlying the improved surface properties are addressed. RP OAK RIDGE NATL LAB, DIV MET & CERAM, POB 2008, OAK RIDGE, TN 37831 USA. NR 34 TC 137 Z9 146 U1 3 U2 16 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 MAR PY 1991 VL 6 IS 3 BP 610 EP 628 DI 10.1557/JMR.1991.0610 PG 19 WC Materials Science, Multidisciplinary SC Materials Science GA FA769 UT WOS:A1991FA76900024 ER PT J AU CURTRIGHT, TL GHANDOUR, GI ZACHOS, CK AF CURTRIGHT, TL GHANDOUR, GI ZACHOS, CK TI QUANTUM ALGEBRA DEFORMING MAPS, CLEBSCH-GORDAN-COEFFICIENTS, COPRODUCTS, R AND U MATRICES SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID YANG-BAXTER EQUATION; CONFORMAL FIELD-THEORIES; RACAH COEFFICIENTS; ANALOG; REPRESENTATIONS; SYMBOLS; SUQ(2); SU(2) AB Quantum algebra deforming maps explicitly define comultiplications that differ from the usual noncocommutative coproducts. Map-induced coproducts are connected to the usual ones by similarity transformations U that may be expressed either in terms of Clebsch-Gordan coefficients, or in a universal operator form. The product of two such U matrices yields the R matrix for a fixed value of the spectral parameter, which bears on the Yang-Baxterization of U as well as R. All this is explicitly illustrated for the tensor product 1/2 x j of SU (2)q using several deforming maps whose coproducts are continuously connected by similarity transformations to form a two-parameter manifold. Some observations are made on the general structure of U and R matrices, and of coproduct manifolds, based on the solutions of hierarchies of partial difference equations. Applications of deforming maps and U matrices to the physics of spin-chains are outlined. C1 UNIV MIAMI,DEPT PHYS,CORAL GABLES,FL 33124. UNIV MIAMI,DEPT MATH,CORAL GABLES,FL 33124. ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. RP CURTRIGHT, TL (reprint author), INST ADV STUDY,SCH NAT SCI,PRINCETON,NJ 08540, USA. RI Curtright, Thomas/B-6840-2015 NR 49 TC 42 Z9 42 U1 0 U2 0 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 MAR PY 1991 VL 32 IS 3 BP 676 EP 688 DI 10.1063/1.529410 PG 13 WC Physics, Mathematical SC Physics GA EZ140 UT WOS:A1991EZ14000015 ER PT J AU HETHERINGTON, MG MILLER, MK AF HETHERINGTON, MG MILLER, MK TI THE CHARACTERIZATION OF MICROSTRUCTURES IN THE ATOM PROBE .1. BERNOULLI SEQUENCES SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE ATOM PROBE; CLUSTERING; ORDERING; FIELD-ION MICROSCOPE; PROBABILITY; STATISTICS; BERNOULLI; MARKOV; MICROSTRUCTURE; FECR, FEBE ID STATISTICAL-ANALYSIS AB The atom probe can be used to characterize fine-scale microstructures. The results presented in this and a subsequent paper attempt to develop a methodology for interpreting information concerning 3-D structures from the sequence of ions detected in the atom probe. Probability theory (Bernoulli trials and Markov processes) is used to build appropriate mathematical descriptions of different types of microstructure. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP HETHERINGTON, MG (reprint author), UNIV OXFORD,DEPT MET & SCI MAT,OXFORD OX1 3PH,ENGLAND. NR 7 TC 2 Z9 2 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD MAR PY 1991 VL 161 BP 473 EP 483 PN 3 PG 11 WC Microscopy SC Microscopy GA FC703 UT WOS:A1991FC70300007 ER PT J AU HETHERINGTON, MG MILLER, MK AF HETHERINGTON, MG MILLER, MK TI THE CHARACTERIZATION OF MICROSTRUCTURES IN THE ATOM PROBE .2. MARKOV SEQUENCES SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE ATOM PROBE; ORDERING; CLUSTERING; FIELD-ION MICROSCOPE; PROBABILITY; STATISTICS; BERNOULLI; MARKOV; MICROSTRUCTURE; FECR AB Mathematical descriptions of typical microstructures which are observed in the atom probe are constructed from the theory of Markov chains. Short-range ordering and clustering, overlapping and non-overlapping particles and spinodal decomposition can all be modelled using this formalism. The models are used to calculate the important autocorrelation function. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP HETHERINGTON, MG (reprint author), UNIV OXFORD,DEPT MET & SCI MAT,OXFORD OX1 3PH,ENGLAND. NR 10 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD MAR PY 1991 VL 161 BP 485 EP 496 PN 3 PG 12 WC Microscopy SC Microscopy GA FC703 UT WOS:A1991FC70300008 ER PT J AU MAGRUDER, RH WEEKS, RA ZUHR, RA WHICHARD, G AF MAGRUDER, RH WEEKS, RA ZUHR, RA WHICHARD, G TI OPTICAL-ABSORPTION OF CU IMPLANTED SILICA SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL OTTO SCHOTT COLLOQUIUM CY JUL 23-27, 1990 CL FRIEDRICH SCHILLER UNIV, JENA, GER DEM REP SP OTTO SCHOTT INST HO FRIEDRICH SCHILLER UNIV ID PHOTOCHROMIC-GLASSES; COPPER; ION; SILVER; COLLOIDS AB The extinction coefficient (EC) per ion was measured over the spectral range from 1.8 to 6.2 eV for a series of Cu ion implanted silica substrates. The substrates were implanted with nominal doses ranging from 0.3 to 12.0 X 10(16) ions/cm2 at substrate temperatures of 100, 296 and 673 K. The EC was observed to increase for both increasing dose and substrate temperature. The absorption in the spectral region < 5.0 eV is attributed to the formation of spherical and oblate spheroidal colloids. At spectral energies > 5.0 eV, the absorption is attributed to radiation damage effects. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN. VANDERBILT UNIV,DEPT MAT SCI & ENGN,NASHVILLE,TN 37240. RP MAGRUDER, RH (reprint author), BELMONT COLL,DEPT PHYS,NASHVILLE,TN 37203, USA. NR 25 TC 41 Z9 42 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD MAR PY 1991 VL 129 IS 1-3 BP 46 EP 53 DI 10.1016/0022-3093(91)90079-L PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FK037 UT WOS:A1991FK03700008 ER PT J AU BLANKENBECLER, R HAGERTY, JJ PULSIFER, DN RINDONE, GE AF BLANKENBECLER, R HAGERTY, JJ PULSIFER, DN RINDONE, GE TI GRADIENT INDEX GLASSES OF MACRO DIMENSIONS AND LARGE UDELTA-N SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL OTTO SCHOTT COLLOQUIUM CY JUL 23-27, 1990 CL FRIEDRICH SCHILLER UNIV, JENA, GER DEM REP SP OTTO SCHOTT INST HO FRIEDRICH SCHILLER UNIV AB Gradient index lens blanks with values of DELTA-n up to 0.5 have been produced by fusing together thin layers of glasses of progressively different indices of refraction. Smooth, step-free gradients are formed by controlled diffusion within and across the layers. Linea, quadratic and a variety of other gradient index profiles may be produced by this method over a wide index range. C1 ISOTEC LTD PARTNERS,TUCSON,AZ 85718. PENN STATE UNIV,DEPT MAT SCI & ENGN,UNIVERSITY PK,PA 16802. RP BLANKENBECLER, R (reprint author), STANFORD LINEAR ACCELERATOR CTR,POB 4349,STANFORD,CA 94309, USA. NR 9 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD MAR PY 1991 VL 129 IS 1-3 BP 109 EP 116 DI 10.1016/0022-3093(91)90085-K PG 8 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FK037 UT WOS:A1991FK03700014 ER PT J AU WRIGHT, AC HULME, RA GRIMLEY, DI SINCLAIR, RN MARTIN, SW PRICE, DL GALEENER, FL AF WRIGHT, AC HULME, RA GRIMLEY, DI SINCLAIR, RN MARTIN, SW PRICE, DL GALEENER, FL TI THE STRUCTURE OF SOME SIMPLE AMORPHOUS NETWORK SOLIDS REVISITED SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL OTTO SCHOTT COLLOQUIUM CY JUL 23-27, 1990 CL FRIEDRICH SCHILLER UNIV, JENA, GER DEM REP SP OTTO SCHOTT INST HO FRIEDRICH SCHILLER UNIV ID NEUTRON-SCATTERING; VITREOUS-SILICA; DIFFRACTION; MODELS; GENERATION; GERMANIUM; GLASSES; SI; GE AB The amorphographic relationships between the structures of a number of single component amorphous network solids are discussed. New neutron diffraction data are introduced for several of the materials including vitreous P2O5 which has not previously been studied by neutron diffraction. These data suggest that network connectivity is more important than structural unit stereochemistry in determining intermediate range order. Previous neutron data for amorphous Ge and vitreous SiO2 are compared with both random network and crystal based models and criteria are proposed for the minimum size of model required to accurately predict the shape of the first diffraction peak, which for a number of amorphous network solids is found to be Lorentzian. It is concluded that new computer modelling techniques are capable of generating models in good agreement with modern diffraction data and should considerably enhance present understanding of the structure of amorphous solids. C1 HARWELL LAB,DIDCOT OX11 0RA,OXON,ENGLAND. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. COLORADO STATE UNIV,FT COLLINS,CO 80523. RP WRIGHT, AC (reprint author), JJ THOMSON PHYS LAB,READING RG6 2AF,ENGLAND. RI Price, David Long/A-8468-2013 NR 38 TC 92 Z9 92 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD MAR PY 1991 VL 129 IS 1-3 BP 213 EP 232 DI 10.1016/0022-3093(91)90098-Q PG 20 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FK037 UT WOS:A1991FK03700027 ER PT J AU HOLAND, W WEBER, MJ AF HOLAND, W WEBER, MJ TI PROCEEDINGS OF THE 4TH INTERNATIONAL SCHOTT,OTTO COLLOQUIUM JENA, GERMAN-DEMOCRATIC-REPUBLIC, JULY 23-27, 1990 - PREFACE SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Editorial Material C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP HOLAND, W (reprint author), UNIV JENA,OTTO SCHOTT INST,O-6900 JENA,GERMANY. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD MAR PY 1991 VL 129 IS 1-3 BP R7 EP R7 DI 10.1016/0022-3093(91)90070-M PG 1 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FK037 UT WOS:A1991FK03700001 ER PT J AU REUTHER, TC AF REUTHER, TC TI A PERSPECTIVE ON THE HISTORY, STATUS AND FUTURE OF FUSION MATERIALS RESEARCH IN THE UNITED-STATES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Fusion materials research and development in the United States began in the early 1970s with ad hoc research using a wide variety of experimental approaches to approximate (in part) the effects that might be expected from the unavailable fusion reactor environment. Charged particle irradiation dominated but important 14 MeV neutron irradiation studies were initiated with the RTNS-I and fission reactor irradiation was started in the HFIR. By the mid '70s, major effort was directed to the definition and development of fusion specific irradiation facilities. Conceptual reactor design studies provided a focus on machine parameters and materials property requirements. Those studies shifted interest to materials that represented more current technology from the earlier focus on refractory metal alloys. In the early 1980s, a strongly structured DOE fusion reactor materials program increasingly focused on international cooperation, including development and use of irradiation facilities. At the present time, international program activities constitute virtually the total DOE fusion materials program. The development of low activation materials is now the primary long term goal, but resources are increasingly focused in support of the next immediate generation of fusion machines, including CIT and ITER. The unfulfilled requirement for an irradiation facility that is relevant to fusion reactor parameters remains the key agenda item before the international fusion materials community. RP REUTHER, TC (reprint author), US DOE,WASHINGTON,DC 20545, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 9 EP 12 DI 10.1016/0022-3115(91)90006-S PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000004 ER PT J AU MIYAHARA, A WHITLEY, JB AF MIYAHARA, A WHITLEY, JB TI THERMAL EFFECTS AND OTHER CRITICAL ISSUES OF PLASMA-FACING COMPONENTS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Plasma-Facing Components (PFC) play a critical role in the operation of magnetic fusion devices, particularly for tokamaks. The heat flux incident on these components during both normal and off-normal operations is high and providing sufficient protection to accommodate erosion plus high thermal conductivity to limit surface temperatures and thermal stresses is a serious design problem, especially for high power devices. The current ITER design activity has demonstrated the importance of achieving high performance design for these components and its impact on the overall machine capabilities and availability. Without a solution to the PFC problem, fusion will not become a viable energy producing option. In this paper, problems in PFC design related to thermal effects for both normal and off-normal loads are indicated and discussed. Design approaches to reduce the problem are suggested from the standpoint of machine control and modifying the component design. Our capability to model these effects will also be discussed. C1 SANDIA NATL LABS,DIV 6428,ALBUQUERQUE,NM 87185. RP MIYAHARA, A (reprint author), NATL INST FUSION SCI,NAGOYA 46401,JAPAN. NR 32 TC 2 Z9 3 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 MAR-APR PY 1991 VL 179 BP 19 EP 24 DI 10.1016/0022-3115(91)90008-U PN A PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000006 ER PT J AU JOHNSON, CE AF JOHNSON, CE TI RESEARCH-AND-DEVELOPMENT STATUS OF CERAMIC BREEDER MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID NEUTRON-IRRADIATED LI2O; TRITIUM RELEASE BEHAVIOR; LITHIUM ALUMINATE; ORTHOSILICATE; EXTRACTION; DIFFUSION; LIOH AB The breeding blanket is a key component of the fusion reactor because it directly involves tritium breeding and energy extraction, both of which are critical to development of fusion power. The lithium ceramics continue to show promise as candidate breeder materials. This promise was also recognized by the International Thermonuclear Experimental Reactor (ITER) design team in its selection of ceramics as the first option breeder material. Blanket design studies have indicated areas in the properties data base that need further investigation. Current studies are focusing on issues such as tritium release behavior at high burnup, changes in thermophysical properties with burnup, compatibility between ceramic breeder and beryllium multiplier, and phase changes with burnup. Laboratory and in-reactor tests are underway, some as part of an international collaboration for development of ceramic breeder materials. RP JOHNSON, CE (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 42 TC 13 Z9 13 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 42 EP 46 DI 10.1016/0022-3115(91)90012-V PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000010 ER PT J AU WIEDERSICH, H AF WIEDERSICH, H TI EFFECTS OF THE PRIMARY RECOIL SPECTRUM ON MICROSTRUCTURAL EVOLUTION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID DEFECT PRODUCTION; ION; IRRADIATION; SIMULATION; CASCADES AB For quantitative predictions and comparisons of microstructures that evolve during exposure to different radiation environments at elevated temperature one needs to develop methods that go beyond those based on the number of displacements per atom. The number of freely migrating defects that contribute to the microstructural development is far less than the total number of defects produced, as has been recognized for some time from measurements of radiation-induced segregation and of radiation-enhanced diffusion. One major reason for the small amount of defects available for long range migration is the high concentration and close spatial correlation of vacancies and, to a somewhat lesser degree, of interstitials in cascades produced by high energy knock-ons. As a consequence, many defects either recombine or form immobile defect clusters during the defect formation and cooling phases of the cascades. After doses exceeding a few tenths of a displacement per atom, the residue of small clusters and dislocation loops of vacancy type remaining in the central portions of energetic cascades and subcascades, is the second major reason for the reduction of the mean free path of defects between creation and annihilation. Defect production in various neutron and ion irradiation environments is discussed in light of these facts. A method to calculate the fraction of freely migrating defects from the cluster size distribution of defects produced in cascades is suggested. The results are in good agreement with available data. RP WIEDERSICH, H (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 25 TC 12 Z9 12 U1 1 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 MAR-APR PY 1991 VL 179 BP 70 EP 75 DI 10.1016/0022-3115(91)90017-2 PN A PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000015 ER PT J AU AVERBACK, RS HSIEH, H DELARUBIA, TD BENEDEK, R AF AVERBACK, RS HSIEH, H DELARUBIA, TD BENEDEK, R TI MOLECULAR-DYNAMICS STUDIES OF DISPLACEMENT CASCADES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID EMBEDDED-ATOM METHOD; NEUTRON-IRRADIATION; TRANSITION-METALS; DISLOCATION LOOPS; TEMPERATURE; SIMULATION; COLLAPSE; COPPER AB Molecular-dynamics simulations of cascades in Cu and Ni with primary-knock-on energies up to 5 keV and lattice temperatures in the range 0-700 K are described. Interatomic forces were represented by either the Gibson II (Cu) or Johnson-Erginsoy (Ni) potentials in most of this work, although some simulations using "Embedded Atom Method" potentials, e.g., for threshold events in Ni3Al, are also presented. The results indicate that the primary state of damage produced by displacement cascades is controlled by two phenomena, replacement collision sequences during the collisional phase of the cascade and local melting during the thermal spike. As expected, the collisional phase is rather similar in Cu and Ni, however, the thermal spike is of longer duration and has a more pronounced influence in Cu than Ni. When the ambient temperature of the lattice is increased, the melt zones are observed to both increase in size and cool more slowly. This has the effect of reducing defect production and enhancing atomic mixing and disordering. The implications of these results for defect production, cascade collapse, atomic disordering will be discussed. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP AVERBACK, RS (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801, USA. NR 35 TC 12 Z9 12 U1 0 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 MAR-APR PY 1991 VL 179 BP 87 EP 93 DI 10.1016/0022-3115(91)90020-8 PN A PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000018 ER PT J AU MANSUR, LK LEE, EH AF MANSUR, LK LEE, EH TI THEORETICAL BASIS FOR UNIFIED ANALYSIS OF EXPERIMENTAL-DATA AND DESIGN OF SWELLING-RESISTANT ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID CRITICAL CAVITY SIZES; ION BOMBARDED 304-SS; IRRADIATED METALS; VOID GROWTH; CRITICAL RADIUS; NUCLEATION; MECHANISMS; KINETICS AB Essential aspects of the theory of radiation-induced swelling are reviewed. In particular, concepts central to the understanding of experimental data and the control of swelling by alloy design are discussed. The knowledge that a critical number of gas atoms is required in a cavity before point defect-driven swelling can begin is a most important contribution of theory. The mathematical expressions that have been derived for calculating this critical quantity are given in terms of materials parameters and irradiation conditions. After swelling begins, its magnitude as a function of dose is governed strongly by the relative sink strengths for point defects of dislocations and cavities, expressed in terms of an index of the microstructure, Q. High swelling and low swelling microstructures can be categorized into four types based on this index. Wide ranges of experimental swelling results covering ferritic/martensitic and austenitic alloys, neutron and ion irradiations and a variety of compositions and irradiation conditions are analyzed and found to be explained consistently within this framework. Based on the understanding gained, approaches to alloy design for swelling resistance are recommended. RP MANSUR, LK (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 30 TC 28 Z9 28 U1 2 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 MAR-APR PY 1991 VL 179 BP 105 EP 110 DI 10.1016/0022-3115(91)90023-Z PN A PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000021 ER PT J AU GARNER, FA AF GARNER, FA TI NEW DEVELOPMENTS IN FUSION MATERIALS RESEARCH USING SURROGATE NEUTRON-SPECTRA SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID MECHANICAL-PROPERTIES; EVOLUTION; HELIUM; ALLOYS AB The use of surrogate irradiation facilities to conduct fusion-relevant materials research requires that fission-fusion correlations be developed to account for the differences between the surrogate and fusion spectra. It is shown that with the exception of Ni-59 isotopic doping of nickel-containing alloys and irradiation in a temperature-controlled environment it is almost impossible to study the effects of helium without introducing other important variables such as displacement rate, temperature history and solid transmutants. When helium effects are studied in the absence of differences in these variables, helium's impact on macroscopic properties is shown to sometimes be second order in magnitude. Differences in displacement rate and temperature history can completely dominate experiments directed toward the study of PKA recoil spectra and helium/dpa ratio. RP GARNER, FA (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 46 TC 4 Z9 4 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 MAR-APR PY 1991 VL 179 BP 111 EP 117 DI 10.1016/0022-3115(91)90024-2 PN A PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000022 ER PT J AU ROWCLIFFE, AF HISHINUMA, A GROSSBECK, ML JITSUKAWA, S AF ROWCLIFFE, AF HISHINUMA, A GROSSBECK, ML JITSUKAWA, S TI RADIATION EFFECTS AT FUSION-REACTOR HE-DPA RATIOS - OVERVIEW OF UNITED-STATES JAPAN SPECTRALLY TAILORED EXPERIMENTS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Spectrally tailored experiments in the Oak Ridge reactors ORR and HFIR are being used to determine the properties of austenitic stainless steels in the relatively unexplored radiation damage regime represented by the proposed ITER first wall and blanket design. These collaborative US/Japan experiments reproduce the temperature (60 to 400-degrees-C), damage rate (approximately 1 MW y/m2), neutron fluences (10 to 30 dpa) and helium generation rates (10 to 15 appm/dpa) typical of the ITER environment. The status of these experiments is described. Following irradiation in the ORR to approximately 8 dpa, data have been obtained on the tensile, swelling, and irradiation creep properties for a variety of austenitic stainless steels. These data are being utilized in the development of design equations. The experiments have been re-encapsulated in assemblies designed for insertion into the new RB* irradiation facilities when the HFIR restarts. C1 JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. RP ROWCLIFFE, AF (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 10 TC 23 Z9 23 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 MAR-APR PY 1991 VL 179 BP 125 EP 129 DI 10.1016/0022-3115(91)90026-4 PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000024 ER PT J AU GROSSBECK, ML MANSUR, LK AF GROSSBECK, ML MANSUR, LK TI LOW-TEMPERATURE IRRADIATION CREEP OF FUSION-REACTOR STRUCTURAL-MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID STAINLESS-STEEL; DISLOCATIONS; DEPENDENCE; ALLOYS; HFIR AB Irradiation creep has been investigated in the Oak Ridge Research Reactor in an assembly spectrally tailored to achieve a He:dpa ratio of 12-14:1 appm/dpa in austenitic stainless steels. Temperatures of 60-400-degrees-C were investigated to address the requirements of near term fusion devices. It was found that austenitic alloys, especially PCA, have higher creep rates at 60-degrees-C than at 330 and 400-degrees-C. Since this phenomenon could not be explained by existing theoretical models, a new mechanism was proposed and a corresponding theoretical model was developed. Since vacancy migration times can be a few orders of magnitude longer than the irradiation times in this temperature regime, the immobile vacancies do not cancel climb produced by mobile interstitials absorbed at dislocations. The result is a high climb rate independent of stress-induced preferred absorption (SIPA) mechanisms. Preliminary calculations indicate that this mechanism coupled with preferred-absorption-driven glide at higher temperatures predicts a high creep rate at low temperatures and a weak temperature dependence of irradiation creep over the entire temperature range investigated. RP GROSSBECK, ML (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 22 TC 21 Z9 21 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 MAR-APR PY 1991 VL 179 BP 130 EP 134 DI 10.1016/0022-3115(91)90027-5 PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000025 ER PT J AU LOOMIS, BA HULL, AB SMITH, DL AF LOOMIS, BA HULL, AB SMITH, DL TI EVALUATION OF LOW-ACTIVATION VANADIUM ALLOYS FOR USE AS STRUCTURAL MATERIAL IN FUSION-REACTORS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID HYDROGEN AB The V-7.2Cr-14.5Ti, V-9.2Cr-4.9Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2 Ti, V-4.1Cr-4.3Ti, Vanstar-7, V-4.6Ti, V-17.7Ti, V-10.0Ti, V-3.1Ti-(0.5-1.0)Si, and V-2.5Ti-1.0Si alloys were evaluated for use as structural material in fusion reactors. The alloys were evaluated on the basis of their unirradiated and neutron-irradiated yield strength; swelling resistance; ductile-brittle transition temperature; resistance to hydrogen, helium, and irradiation embrittlement; and compatibility with a lithium reactor coolant. On the basis of these evaluations, alloys of V-(0-7)Cr-(5-10)Ti-(0-1)Si are recommended for more intensive evaluation for use as structural material in fusion reactors. C1 ARGONNE NATL LAB,FUSION POWER PROGRAM,ARGONNE,IL 60439. RP LOOMIS, BA (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 27 TC 40 Z9 41 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 MAR-APR PY 1991 VL 179 BP 148 EP 154 DI 10.1016/0022-3115(91)90030-B PN A PG 7 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000028 ER PT J AU SMID, I CROESSMANN, CD SALMONSON, JC WHITLEY, JB KNY, E REHEIS, N KNERINGER, G NICKEL, H AF SMID, I CROESSMANN, CD SALMONSON, JC WHITLEY, JB KNY, E REHEIS, N KNERINGER, G NICKEL, H TI BRAZED GRAPHITE REFRACTORY-METAL COMPOSITES FOR 1ST-WALL PROTECTION ELEMENTS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m2. The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000-degrees-C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/3Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 50 x 50 mm2 with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with an average heat flux of 10 MW/m2 for 0.5 s pulses. The maximum surface temperature was 1100-degrees-C. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model. C1 MET WERK PLANSEE GMBH,A-6600 REUTTE,AUSTRIA. ASSOC EURATOM KFA,KERNFORSCHUNGSANLAGE JULICH,INST REAKTORWERKSTOFFE,W-5170 JULICH,GERMANY. RP SMID, I (reprint author), SANDIA NATL LABS,DIV FUSION TECHNOL 6428,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 6 TC 1 Z9 1 U1 1 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 MAR-APR PY 1991 VL 179 BP 169 EP 172 PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000029 ER PT J AU BURCHELL, TD EATHERLY, WP AF BURCHELL, TD EATHERLY, WP TI THE EFFECTS OF RADIATION-DAMAGE ON THE PROPERTIES OF GRAPHNOL N3M SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID THERMAL-SHOCK RESISTANCE AB GraphNOL N3M (N3M) is a bulk graphite developed at Oak Ridge National Laboratory (ORNL) for advanced structural applications in aerospace thermal protection systems. It is currently of interest to the United States fusion energy community for plasma facing components, such as the first wall armor tiles of the International Thermonuclear Experimental Reactor (ITER) because of its superior thermal shock resistance and irradiation lifetime. This paper reports the results of irradiation experiments on N3M graphite at two temperatures, 600 and 875-degrees-C in the High Flux Isotope Reactor (HFIR) at ORNL. Maximum fluences of 4.2 x 10(26) and 2 x 10(26) n/m2 (E > 50 keV) or 28.4 and 13.5 dpa (graphite) were attained at 600 and 875-degrees-C, respectively. Data are presented on the dimensional stability, volume change, strength, Young's modulus, critical stress intensity factor K(Ic), and coefficient of thermal expansion (CTE). The thermal shock resistance of GraphNOL N3M is discussed and comparisons made with other graphites. The influence of irradiation damage on thermal shock resistance is postulated. RP BURCHELL, TD (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. RI Burchell, Tim/E-6566-2017 OI Burchell, Tim/0000-0003-1436-1192 NR 16 TC 31 Z9 31 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 MAR-APR PY 1991 VL 179 BP 205 EP 208 DI 10.1016/0022-3115(91)90062-C PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000038 ER PT J AU GARNER, FA BRAGER, HR ANDERSON, KR AF GARNER, FA BRAGER, HR ANDERSON, KR TI NEUTRON-INDUCED CHANGES IN DENSITY AND ELECTRICAL-CONDUCTIVITY OF COPPER-ALLOYS AT 16 TO 98 DPA AND 430-DEGREES-C SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB An irradiation experiment on copper alloys in the Fast Flux Test Facility (FFTF) at 430-degrees-C has been completed. Four exposure levels were reached with the maximum at 98 dpa. Immersion density measurements of a wide variety of copper alloys show swelling values ranging from 1 to 64% at 98 dpa. Copper that is dispersion-strengthened with 0.25% Al2O3 (designated Al25) appears to be the most swelling resistant and promising high conductivity alloy. The steady-state swelling rate of relatively simple copper alloys was found to be approximately 0.5%/dpa at 430-degrees-C. Both the swelling and conductivity changes of the pure copper reference alloy were found to be very reproducible. C1 WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. UNIV ILLINOIS, URBANA, IL 61801 USA. RP GARNER, FA (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 11 TC 30 Z9 30 U1 1 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 MAR-APR PY 1991 VL 179 BP 250 EP 253 DI 10.1016/0022-3115(91)90073-G PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000049 ER PT J AU MILLER, TJ ZINKLE, SJ CHIN, BA AF MILLER, TJ ZINKLE, SJ CHIN, BA TI STRENGTH AND FATIGUE OF DISPERSION-STRENGTHENED COPPER SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The tensile and fatigue properties of cold-worked copper and a commercial Cu-Al2O3 dispersion-strengthened alloy were measured at temperatures between 25 and 600-degrees-C. The GLIDCOP Al-15 alloy, which contains 0.15 wt% Al in the form of Al2O3 particles, exhibited a significantly higher tensile and fatigue strength than copper under all test conditions. The mechanical properties of this alloy appear to be suitable for high-strength, high-conductivity alloy applications in fusion reactors. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. RP MILLER, TJ (reprint author), AUBURN UNIV, DEPT MECH ENGN, AUBURN, AL 36849 USA. OI Zinkle, Steven/0000-0003-2890-6915 NR 14 TC 31 Z9 31 U1 3 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 EI 1873-4820 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 263 EP 266 DI 10.1016/0022-3115(91)90076-J PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000052 ER PT J AU BALDWIN, DL SLAGLE, OD GELLES, DS AF BALDWIN, DL SLAGLE, OD GELLES, DS TI TRITIUM RELEASE FROM IRRADIATED BERYLLIUM AT ELEVATED-TEMPERATURES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Tritium release kinetics have been measured for neutron-irradiated beryllium in the temperature range of 573-884 K. Two tritium release tests of 270 and 550 h are the first in a series of tritium release tests on irradiated Be in support of International Thermonuclear Experimental Reactor (ITER) blanket designs. Real-time tritium release curves were measured after temperature step changes of 100 K by an ionization chamber under conditions specific to ITER. The conditions and experiment were designed to measure diffusion-controlled release from irradiated Be. The preliminary conclusion from this data set is that a unique rate-controlling mechanism is not distinguishable. Apparent diffusion kinetics at lower temperatures give way to a burst release at 884 K, coincident with a restructuring and bubble coalescence in this fully dense material. RP BALDWIN, DL (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 7 TC 23 Z9 23 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 MAR-APR PY 1991 VL 179 BP 329 EP 334 DI 10.1016/0022-3115(91)90093-M PN A PG 6 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000069 ER PT J AU MOLLA, J IBARRA, A FROST, HM CLINARD, FW KENNEDY, JC DECASTRO, MJ AF MOLLA, J IBARRA, A FROST, HM CLINARD, FW KENNEDY, JC DECASTRO, MJ TI THE EFFECT OF ZRO2 DOPING ON MECHANICAL AND DIELECTRIC-PROPERTIES OF AL2O3 AND MGAL2O4 SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID BEHAVIOR; CERAMICS; TRANSFORMATIONS AB Different samples of zirconia-doped alumina and spinel ceramics have been obtained and characterized. Their mechanical and dielectric properties at high frequencies have been measured. The dependence of these properties on the concentrations of the different zirconia phases is discussed. From the results obtained it is concluded that the dispersion of tetragonal zirconia particles in the ceramics causes strength and toughness to be improved without almost any degradation in dielectric properties, while monoclinic zirconia increases the dielectric loss. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP MOLLA, J (reprint author), ASOC EURATOM CIEMAT FUSION,AVDA COMPLUTENSE 22,E-28040 MADRID,SPAIN. RI Jimenez de Castro, Miguel/H-6062-2015; Molla, Joaquin/L-2468-2015; OI Jimenez de Castro, Miguel/0000-0002-2816-0394; Molla, Joaquin/0000-0001-5407-1611; Ibarra, Angel/0000-0002-2420-2497 NR 17 TC 5 Z9 6 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 MAR-APR PY 1991 VL 179 BP 375 EP 378 DI 10.1016/0022-3115(91)90103-E PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000079 ER PT J AU COGHLAN, WA CLINARD, FW AF COGHLAN, WA CLINARD, FW TI DAMAGE TO MACOR GLASS-CERAMIC FROM HIGH-DOSE 14 MEV NEUTRONS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Macor machinable glass-ceramic was irradiated to fluences up to 1 x 10(23) 14 MeV n/m2 at room temperature. Post-irradiation measurements were carried ut to determine changes in high-frequency electrical conductivity, hardness, and density. It was found that neutron damage caused slight increases in conductivity and hardness. The major change noted was in density, where a fluence of 4 x 10(22) n/m2 caused swelling of 1.55 vol% while a dose of 1 x 10(23) n/m2 resulted in a lower swelling value (0.82 vol%). This unusual behavior is explained by a model involving expansion of the mica phase of Macor and contraction of the glassy phase. Implications of the present results for engineering performance of Macor at these and higher fluences are discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP COGHLAN, WA (reprint author), GRAND CANYON UNIV,DEPT PHYS,PHOENIX,AZ 85017, USA. NR 11 TC 8 Z9 8 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 391 EP 394 DI 10.1016/0022-3115(91)90107-I PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000083 ER PT J AU ZINKLE, SJ KOJIMA, S AF ZINKLE, SJ KOJIMA, S TI HELIUM-ASSISTED CAVITY FORMATION IN ION-IRRADIATED CERAMICS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID MAGNESIUM ALUMINATE; RADIATION-DAMAGE; MICROSTRUCTURE; ALPHA-AL2O3 AB Polycrystalline specimens of spinel (MgAl2O4) and alumina (Al2O3) were irradiated at room temperature and 650-degrees-C with either dual- or triple-ion beams in order to investigate the effects of simultaneous displacement damage and helium implantation on cavity formation. The cavities in alumina were aligned along the direction of the c-axis, with diameters ranging from < 2 to 10 nm. The cavities in spinel were preferentially associated with dislocation loops and were of similar size as the cavities in alumina. Catastrophic amounts of cavitation were observed at the grain boundaries in spinel when the displacement damage level exceeded a critical value (approximately 20 dpa) in the presence of a fusion-relevant (approximately 60 appm/dpa) helium environment. RP ZINKLE, SJ (reprint author), OAK RIDGE NATL LAB, DIV MET & CERAM, POB 2008, OAK RIDGE, TN 37831 USA. OI Zinkle, Steven/0000-0003-2890-6915 NR 17 TC 30 Z9 30 U1 2 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 MAR-APR PY 1991 VL 179 BP 395 EP 398 DI 10.1016/0022-3115(91)90108-J PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000084 ER PT J AU ELLIOTT, C ENMARK, M LUCAS, GE ODETTE, GR ROWCLIFFE, A AF ELLIOTT, C ENMARK, M LUCAS, GE ODETTE, GR ROWCLIFFE, A TI DEVELOPMENT OF DISK COMPACT TENSION SPECIMENS AND TEST TECHNIQUES FOR HFIR IRRADIATIONS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID FRACTURE AB Near term irradiations of candidate alloys being planned for the High Flux Isotope Reactor (HFIR) in support of ITER and isotope tailoring experiments necessitate the use of relatively small fracture toughness specimens, e.g. down to 12.5 mm in diameter. The specimens will also contain substantial amounts of helium. This paper describes the application of electropotential drop techniques to determine J-resistance curves for this purpose in HT-9 specimens with diameters of 40, 25 and 12.5 mm; in addition, the effects of side grooving were examined. Good agreement between J-resistance curves determined by the electropotential drop and by multiple specimen techniques were obtained for all specimen geometries and sizes. A systematic decrease in J(IC) with specimen thickness was observed for both side-grooved and smooth specimens with thicknesses below the validity criterion. The tearing modulus was reduced by side grooving but was less dependent on specimen size. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP ELLIOTT, C (reprint author), UNIV CALIF SANTA BARBARA,DEPT CHEM & NUCL ENGN,SANTA BARBARA,CA 93106, USA. NR 15 TC 9 Z9 9 U1 1 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 MAR-APR PY 1991 VL 179 BP 434 EP 437 DI 10.1016/0022-3115(91)90117-P PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000093 ER PT J AU RAO, GR ROWCLIFFE, A CHIN, BA AF RAO, GR ROWCLIFFE, A CHIN, BA TI DEVELOPMENT OF MINIATURE BENDING FATIGUE SPECIMENS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Two new miniaturized bending fatigue specimens have been designed and developed to aid in the scoping of materials for fusion first-wall and blanket structural applications. One of these is rectangular in shape with a gauge section 6.35 mm in length, while the other is cut from a 3 mm transmission electron microscopy (TEM) disk and has a gauge length of 1.5 mm. Test results for unirradiated annealed type 316 stainless steel tested at room temperature, 550-degrees-C and 650-degrees-C are presented. A good correlation between miniature and standard subsize fatigue specimen results was obtained. The miniature specimen results show the same dependence of strain range on cycles to failure as the standard subsize specimens with the miniature-disk specimen results failling below all the other results. The results indicate that these specimens provide reliable data that can be used to scope fatigue properties for fusion applications. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37830. RP RAO, GR (reprint author), AUBURN UNIV,AUBURN,AL 36849, USA. NR 7 TC 4 Z9 4 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 MAR-APR PY 1991 VL 179 BP 438 EP 440 DI 10.1016/0022-3115(91)90118-Q PN A PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000094 ER PT J AU OKADA, A HAMILTON, ML GARNER, FA AF OKADA, A HAMILTON, ML GARNER, FA TI MICROBULGE TESTING APPLIED TO NEUTRON-IRRADIATED MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Microbulge testing was conducted on several Fe-Ni-Cr alloys irradiated as 0.3 mm thick disks to 10 dpa at 603 and 773 K in the Oak Ridge Research Reactor. Miniature tensile tests were also performed on specimens of the same alloys irradiated concurrently. Good correlation between the tensile yield strength and the bulge yield load was observed in unirradiated specimens, however, the correlation was not simple for irradiated specimens. Good correlation was also observed between the ultimate tensile strength and the maximum bulge load. While irradiation produced a significant reduction in total elongation in the tensile test, irradiation caused only a small decrease in the deflection corresponding to the maximum bulge load compared to that observed on thinner disks used at earlier experiments. The results suggest that the thinner disk is better suited for ductility evaluations than the thicker disk. The area bounded by the load-deflection traces of the bulge tests shows a systematic variation with both alloy composition and irradiation condition which is not observed in the tensile data. It is anticipated that this parameter may prove useful in the evaluation of the materials' toughness. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP OKADA, A (reprint author), HOKKAIDO UNIV, DEPT PRECIS ENGN, SAPPORO, HOKKAIDO 060, JAPAN. NR 11 TC 9 Z9 9 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 MAR-APR PY 1991 VL 179 BP 445 EP 448 DI 10.1016/0022-3115(91)90120-V PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000096 ER PT J AU KAWANISHI, H GARNER, FA SIMONS, RL AF KAWANISHI, H GARNER, FA SIMONS, RL TI SYNERGISTIC EFFECTS OF HELIUM AND OTHER VARIABLES ON MICROSTRUCTURE CHANGE IN NEUTRON-IRRADIATED FE-NI-CR ALLOYS DOPED WITH NI-59 SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID PHOSPHORUS; BEHAVIOR AB Microstructural data have been described on Fe-15Cr-xNi-yP alloys in both solution-annealed and cold-worked conditions irradiated in the Fast Flux Test Facility (FFTF) reactor at 638 and 873 K to 5.2 and 8.8 dpa, respectively, where x = 25 to 45 and y = 0.001 to 0.04. The irradiation was carried out on each alloy condition exhibiting two variants in the ratio of Ni-59 isotope. TEM examinations have been conducted to study the role of He/dpa ratio, Ni content, P level, thermal-mechanical condition and irradiation temperature on the development of neutron-induced microstructure. The results obtained show that prior-cold working, higher Ni content and higher P level usually suppress swelling. Higher He generation rate does not always enhance swelling. Phosphide was precipitated only at 873 K. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. RP KAWANISHI, H (reprint author), UNIV TOKYO, DEPT NUCL ENGN, 7-3-1 HONGO, BUNKYO KU, TOKYO 113, JAPAN. NR 10 TC 14 Z9 14 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 MAR-APR PY 1991 VL 179 BP 511 EP 514 DI 10.1016/0022-3115(91)90137-V PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000113 ER PT J AU HAMADA, S SUZUKI, M MAZIASZ, PJ HISHINUMA, A AF HAMADA, S SUZUKI, M MAZIASZ, PJ HISHINUMA, A TI MICROSTRUCTURAL EVOLUTION IN AUSTENITIC STAINLESS-STEELS IRRADIATED TO 57 DPA IN HFIR SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Austenitic stainless steels with different levels of titanium and carbon - JPCA, Type 316 and two heats of low-carbon steel - were irradiated in the solution-annealing (SA) and cold-worked (CW) conditions in HFIR at 500-degrees-C to doses of about 34 and 57 dpa. Their swelling behavior was investigated, with emphasis on the microstructural evolution. Swelling was low (< 2%) in all CW steels after 57 dpa, but was much higher in the SA steels. The JPCA and especially the low-carbon heats with titanium (and/or niobium) irradiated in the SA condition had much more swelling than SA 316. In the CW steels, microstructures of fine dispersions of helium bubbles and fine precipitates of MC or M6C remain stable over the dose range, with very little void formation. By contrast, SA steels in which either MC dissolved or coarse particles of M6C and/or G phase evolved unstably in association with large voids showed the worst swelling from 34 to 57 dpa. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP HAMADA, S (reprint author), JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. OI Maziasz, Philip/0000-0001-8207-334X NR 9 TC 7 Z9 7 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 MAR-APR PY 1991 VL 179 BP 515 EP 518 DI 10.1016/0022-3115(91)90138-W PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000114 ER PT J AU SAWAI, T MAZIASZ, PJ HISHINUMA, A AF SAWAI, T MAZIASZ, PJ HISHINUMA, A TI MICROSTRUCTURAL EVOLUTION OF WELDED AUSTENITIC STAINLESS-STEELS IRRADIATED IN THE SPECTRALLY-TAILORED ORR EXPERIMENT AT 400-DEGREES-C SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID STABILITY; HFIR AB Microstructural evolution of austenitic stainless steels and their welds has been examined after spectrally-tailored neutron irradiation. JPCA and 316W, containing 0.24 and 0.08 wt% of titanium, respectively, were electron-beam welded. TEM disks taken from these weld joints were irradiated in the ORR (Oak Ridge Research Reactor), to 7.4 dpa and almost 100 appm He. Base metal specimens of 316R with very low titanium content (0.005 wt%) were also irradiated. Specimens were examined by precision immersion densitometry before TEM observation. Only the 316R base metal showed measurable swelling by density change. Cavity swelling, determined by TEM observations in the base metals, was 0.29% for 316R, 0.06% for 316W and 0.03% for JPCA. Titanium effectively suppressed the cavity swelling of the base metals. The cellular microstructure of fusion zone remained after this irradiation both in JPCA and 316W with uniform distribution of cavities. Welding did not degrade the swelling resistance as measured either by immersion densitometry or TEM. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP SAWAI, T (reprint author), JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. NR 14 TC 9 Z9 9 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 519 EP 522 DI 10.1016/0022-3115(91)90139-X PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000115 ER PT J AU STUBBINS, JF GARNER, FA AF STUBBINS, JF GARNER, FA TI THE RELATIVE INFLUENCE OF HELIUM DPA RATIO AND OTHER VARIABLES ON NEUTRON-INDUCED SWELLING OF FE-NI-CR ALLOYS AT 495-DEGREES-C AND 14 DPA SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID PHOSPHORUS AB An isotopic tailoring experiment utilizing Ni-59 has been conducted in the Fast Flux Test Facility (FFTF) to study the influence of helium/dpa ratio on neutron-induced microstructural evolution. The influence of other variables, namely composition (nickel and phosphorous variations), and cold work on swelling was also examined. The alloys, Fe-25Ni-15Cr, Fe-25Ni-15Cr-0.04P, and Fe-45Ni-15Cr, were each irradiated in four conditions: solution annealed or 20% cold worked both with and without Ni-59 additions, yielding He/dpa ratios of 0.35 and 4.7 at 25Ni and 0.57 and 4.9 at 45Ni. Increases in helium were found to alter the details of microstructural evolution somewhat at 495-degrees-C, but the effect of helium was small compared to the effects of other variables studied. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP STUBBINS, JF (reprint author), UNIV ILLINOIS, 103 S GOODWIN AVE, URBANA, IL 61801 USA. NR 15 TC 10 Z9 10 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 MAR-APR PY 1991 VL 179 BP 523 EP 525 DI 10.1016/0022-3115(91)90140-3 PN A PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000116 ER PT J AU MUROGA, T GARNER, FA OHNUKI, S AF MUROGA, T GARNER, FA OHNUKI, S TI MICROSTRUCTURAL INVESTIGATION OF SWELLING DEPENDENCE ON NICKEL CONTENT IN FAST NEUTRON-IRRADIATED FE-CR-NI AUSTENITIC TERNARIES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID ALLOYS AB Microstructures of Fe-15Cr-xNi(x = 15, 19, 21, 30, 35, 45, 75) ternary alloys and a 15Cr-85Ni binary alloy irradiated in the EBR-II reactor at 510-degrees-C and 538-degrees-C to various neutron fluences were examined by TEM. At 510-degrees-C void nucleation was complete prior to the onset of steady-state swelling at all nickel levels, implying that some process other than void nucleation determines when the relatively rapid void growth associated with the onset of steady-state swelling occurs. The protracted loop dominance of dislocation structure and the relatively low void density at intermediate nickel levels (30-45 wt%) suggested a reduced dislocation bias toward preferential interstitial absorption as a possible mechanism to produce lower swelling in this nickel range. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. HOKKAIDO UNIV, FAC ENGN, SAPPORO, HOKKAIDO 060, JAPAN. RP MUROGA, T (reprint author), KYUSHU UNIV, APPL MECH RES INST, KASUGA, FUKUOKA 816, JAPAN. RI U-ID, Kyushu/C-5291-2016; Kyushu, RIAM/F-4018-2015 NR 14 TC 17 Z9 17 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 546 EP 549 DI 10.1016/0022-3115(91)90146-X PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000122 ER PT J AU GARNER, FA HAMILTON, ML SIMONS, RL MAXON, MK AF GARNER, FA HAMILTON, ML SIMONS, RL MAXON, MK TI ISOTOPIC TAILORING WITH NI-59 TO STUDY THE INFLUENCE OF HELIUM DPA RATIO ON TENSILE PROPERTY CHANGES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID PHOSPHORUS; ALLOYS AB Irradiation of miniature tensile specimens of simple model Fe-Cr-Ni alloys is proceeding in the Fast Flux Test Facility to study the interactive effects of alloy composition, cold work level, helium/dpa ratio and irradiation temperature on the evolution of microstructure and associated changes in mechanical properties. The addition of Ni-59 to these alloys allows side-by-side irradiation of otherwise identical specimens, differing only in helium/dpa ratio. In the absence of differences in displacement rate and temperature history, it is shown that helium in this experiment exerts a rather small influence on tensile properties at 365 and 600-degrees-C. While the saturation level of yield stress in Fe-25Ni-15Cr is strongly dependent on irradiation temperature, it is relatively insensitive to cold work level and helium/dpa ratio. The yield strength of Fe-25Ni-15Cr, both unirradiated and irradiated at 365-degrees-C, is increased slightly by addition of 0.04 wt% phosphorus. C1 WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. WASHINGTON STATE UNIV, NW COLL, RICHLAND, WA 99352 USA. WASHINGTON STATE UNIV, UNIV ASSOC SCI, RICHLAND, WA 99352 USA. RP GARNER, FA (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 18 TC 13 Z9 13 U1 1 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 MAR-APR PY 1991 VL 179 BP 554 EP 557 DI 10.1016/0022-3115(91)90148-Z PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000124 ER PT J AU HAMILTON, ML OKADA, A GARNER, FA AF HAMILTON, ML OKADA, A GARNER, FA TI TENSILE BEHAVIOR AND SWELLING OF TERNARY AUSTENITIC ALLOYS IRRADIATED IN DIFFERENT NEUTRON-SPECTRA SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Two nominally identical experiments were designed to study the effects of nickel, chromium, cold work and helium generation rate on neutron-induced swelling and changes in tensile properties of simple Fe-Cr-Ni alloys. One was conducted in the Oak Ridge Research Reactor (ORR) at higher He/dpa ratios and lower displacement rates than the other, conducted in the Experimental Breeder Reactor II (EBR-II). The ORR results are at higher dpa levels and show substantially more strengthening and a different temperature range of swelling. C1 HOKKAIDO UNIV, SAPPORO, HOKKAIDO 060, JAPAN. RP HAMILTON, ML (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 12 TC 10 Z9 10 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 MAR-APR PY 1991 VL 179 BP 558 EP 562 DI 10.1016/0022-3115(91)90149-2 PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000125 ER PT J AU JITSUKAWA, S GROSSBECK, ML HISHINUMA, A AF JITSUKAWA, S GROSSBECK, ML HISHINUMA, A TI STRESS-STRAIN RELATIONS OF HFIR-IRRADIATED AUSTENITIC STAINLESS-STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Tensile specimens of austenitic stainless steels were irradiated up to 50 dpa at temperature of 573, 673 and 773 K and HFIR. True stress-strain relation derived from the load-displacement curves were analyzed in terms of induced effective strain and strain hardening behavior. The strain hardening exponent of the material was only slightly affected by irradiation at 573 and 673 K. Irradiation at 773 K changes work hardening characteristics. This might have resulted from fine MC precipitation and/or helium produced during irradiation. Fracture strain decreases with dose, and the dose dependence was pronounced at 773 K. Heat-to-heat variation was not large between two Ti-modified steels. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP JITSUKAWA, S (reprint author), JAPAN ATOM ENERGY RES INST,DEPT FUELS & MAT RES,TOKAI,IBARAKI 31911,JAPAN. NR 9 TC 13 Z9 13 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 563 EP 567 DI 10.1016/0022-3115(91)90150-6 PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000126 ER PT J AU GROSSBECK, ML AF GROSSBECK, ML TI EMPIRICAL RELATIONS FOR TENSILE PROPERTIES OF AUSTENITIC STAINLESS-STEELS IRRADIATED IN MIXED-SPECTRUM REACTORS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB An assessment has been made of available tensile property data relevant to the design of fusion reactors, especially near term devices expected to operate at lower temperatures than power reactors. Empirical relations have been developed for the tensile properties as a function of irradiation temperature for neutron exposures of 10-15, 20, 30, and 50 dpa. It was found that yield strength depends little on the particular austenitic alloy and little on the helium concentration. Strength depends upon initial condition of the alloy only for exposures of less than 30 dpa. Uniform elongation was found to be more sensitive to alloy and condition. It was also more sensitive than strength to helium level. However, below 500-degrees-C, helium only appeared to have an effect at 10-15 dpa. At higher temperatures, helium embrittlement was apparent, and its threshold temperature decreased with increasing neutron exposure level. RP GROSSBECK, ML (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 14 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 568 EP 571 DI 10.1016/0022-3115(91)90151-V PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000127 ER PT J AU GARNER, FA PUIGH, RJ AF GARNER, FA PUIGH, RJ TI IRRADIATION CREEP AND SWELLING OF THE FUSION HEATS OF PCA, HT9 AND 9CR-1MO IRRADIATED TO HIGH NEUTRON FLUENCE SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID EXPOSURES AB The irradiation creep and swelling at 400-750-degrees-C of the fusion heats of PCA, HT9 and 9Cr-1Mo were studied using pressurized tubes irradiated in the Fast Flux Test Facility (FFTF). At temperatures less-than-or-equal-to 550-degrees-C the irradiation creep of all three alloys was found to be proportional to the stress level and the instantaneous swelling rate. Although swelling is sensitive to temperature, stress, alloy type, cold work and composition, the creep-swelling coupling coefficient does not appear to be very sensitive to these variables. C1 WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. RP GARNER, FA (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 12 TC 34 Z9 35 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 MAR-APR PY 1991 VL 179 BP 577 EP 580 DI 10.1016/0022-3115(91)90153-X PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000129 ER PT J AU PORTER, DL HUDMAN, GD GARNER, FA AF PORTER, DL HUDMAN, GD GARNER, FA TI IRRADIATION CREEP AND SWELLING OF ANNEALED TYPE-304L STAINLESS-STEEL AT APPROXIMATELY 390-DEGREES-C AND HIGH NEUTRON FLUENCE SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID EXPOSURES AB The irradiation-induced creep and swelling of annealed AISI 304L in EBR-II at approximately 390-degrees-C have been investigated to exposures of approximately 80 dpa and compared with the behavior of AISI 316 and PCA stainless steels. While swelling depends on stress, displacement rate, composition and cold-work level, the creep rate directly depends only on the stress level and the instantaneous swelling rate. The creep-swelling coupling coefficient of austenitic alloys at approximately 400-degrees-C does not appear to be very sensitive to composition or cold work level. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP PORTER, DL (reprint author), ARGONNE NATL LAB, 9700 S CASS AVE, ARGONNE, IL 60439 USA. NR 14 TC 35 Z9 35 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 581 EP 584 DI 10.1016/0022-3115(91)90154-Y PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000130 ER PT J AU JONES, RH BRUEMMER, SM HENAGER, CH AF JONES, RH BRUEMMER, SM HENAGER, CH TI STRESS-CORROSION CRACKING ISSUES RELATED TO A WATER-COOLED ITER SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB A review of water impurity and temperature effects on stress-corrosion cracking of austenitic stainless steel is presented. These results demonstrate that stress-corrosion crack growth can occur at ITER relevant temperatures for certain water chemistries and material conditions. A model developed at PNL to calculate the degree of sensitization was used to estimate the potential for sensitization of Type 316 SS and US PCA. This analysis shows that both materials can be severely sensitized but, with proper processing and fabrication, sensitization should be avoidable. RP JONES, RH (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. OI Henager, Chuck/0000-0002-8600-6803 NR 21 TC 2 Z9 2 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 MAR-APR PY 1991 VL 179 BP 607 EP 610 DI 10.1016/0022-3115(91)90161-Y PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000137 ER PT J AU BELL, GEC TORTORELLI, PF KENIK, EA KLUEH, RL AF BELL, GEC TORTORELLI, PF KENIK, EA KLUEH, RL TI AN INVESTIGATION OF THE SENSITIZATION BEHAVIOR OF FE-MN-CR AUSTENITIC STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Standard chemical immersion (modified Strauss) tests and analytical electron microscopy (AEM) showed that reduced activation austenitic steels based on Fe-20Mn-12Cr-0.25C(wt%) are extremely prone to thermal sensitization and intergranular corrosion because of their high carbon contents and low chromium concentrations. This susceptibility to sensitization after thermal aging, fabrication, or irradiation makes their use in aqueous and other certain environments problematical. Excellent correlation between intergranular corrosion induced by immersion in the acidified CuSO4 solution and the presence of narrow chromium-depleted zones around grain boundaries, as determined by AEM, was found. Due to the need to meet reduced activation requirements, the opportunities to increase the sensitization resistance of fully austenitic Fe-Mn-Cr steels by alloy design are limited. RP BELL, GEC (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Tortorelli, Peter/E-2433-2011 NR 10 TC 6 Z9 6 U1 1 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 MAR-APR PY 1991 VL 179 BP 615 EP 618 DI 10.1016/0022-3115(91)90163-2 PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000139 ER PT J AU INAZUMI, T BELL, GEC KIUCHI, K AF INAZUMI, T BELL, GEC KIUCHI, K TI ELECTROCHEMICAL EVALUATION OF SENSITIZATION IN AUSTENITIC STAINLESS-STEELS USING MINIATURIZED SPECIMENS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB An electrochemical testing system was developed to evaluate the sensitization of neutron-irradiated austenitic stainless steels using miniaturized disk-type specimens, 3 mm in diameter and 0.25 mm thick. The system consists of a specimen holder in which a miniaturized specimen is mounted as the working electrode, a test cell designed to handle radioactive materials and waste, a computer-controlled potentiostat/galvanostat and a surface preparation equipment. Sensitization of a thermally-aged Ti-modified austenitic stainless steel was successfully detected by the single-loop electrochemical potentiokinetic reactivation (SL-EPR) method. C1 OAK RIDGE ASSOCIATED UNIV,OAK RIDGE,TN 37831. JAPAN ATOM ENERGY RES INST,DEPT FUELS & MAT RES,TOKAI,IBARAKI 31911,JAPAN. NR 17 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 619 EP 622 DI 10.1016/0022-3115(91)90164-3 PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000140 ER PT J AU MCCARTHY, JM AF MCCARTHY, JM TI PHASE EVOLUTION DURING NEUTRON-IRRADIATION OF COMMERCIAL FE-CR-MN ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID BEHAVIOR AB Earlier irradiation studies on simple Fe-Mn and Fe-Cr-Mn alloys in the annealed condition showed that these alloys exhibited a higher level of phase instability than do comparable Fe-Cr-Ni alloys. Contributing to this instability was the tendency of iron to segregate at microstructural sinks due to the operation of the inverse Kirkendall effect. This segregation, combined with the addition of various solutes and the application of typical thermomechanical treatments to produce the commercial alloys, added complexity to the phase evolution of Fe-Cr-Mn alloys. This complexity included the intergranular and intragranular precipitation of M23C6 carbide, alpha ferrite, and sigma. These phases can have detrimental effects on mechanical and corrosion properties. Provided that the phase transformations to sigma and carbides can be controlled, the commercial austenitic Fe-Cr-Mn alloys appear to be suitable starting compositions for the development of low activation alloys for service in fusion reactors. RP MCCARTHY, JM (reprint author), PACIFIC NW LAB, DEPT MAT SCI, POB 999, RICHLAND, WA 99352 USA. NR 9 TC 4 Z9 4 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 MAR-APR PY 1991 VL 179 BP 626 EP 628 DI 10.1016/0022-3115(91)90166-5 PN A PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000142 ER PT J AU GARNER, FA BRAGER, HR TAKAHASHI, H AF GARNER, FA BRAGER, HR TAKAHASHI, H TI NEUTRON-INDUCED SWELLING OF MODEL FE-CR-MN-NI ALLOYS AND COMMERCIAL MANGANESE-STABILIZED STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID AUSTENITIC ALLOYS; IRRADIATION; BEHAVIOR AB The addition of nickel to both simple and solute-modified Fe-Cr-Mn alloys leads initially to an increase in neutron-induced swelling. The addition of various minor solutes, particularly silicon, in general leads to a reduction in swelling. Depending on composition, thermomechanical condition and irradiation temperature, a wide variety of swelling behavior is observed in various commercial Fe-Cr-Mn alloys. There is some indication in the commercial alloys of massive formation of ferrite phases during irradiation at 420-degrees-C, leading to a reduction in the swelling rate. C1 WESTINGHOUSE HANFORD CO, RICHLAND, WA 99352 USA. HOKKAIDO UNIV, SAPPORO, HOKKAIDO 060, JAPAN. RP GARNER, FA (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 6 TC 8 Z9 8 U1 1 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 MAR-APR PY 1991 VL 179 BP 633 EP 636 DI 10.1016/0022-3115(91)90168-7 PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000144 ER PT J AU KLUEH, RL MAZIASZ, PJ ALEXANDER, DJ AF KLUEH, RL MAZIASZ, PJ ALEXANDER, DJ TI HEAT-TREATMENT EFFECT ON IMPACT PROPERTIES OF REDUCED-ACTIVATION STEELS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID CR-W STEELS; MICROSTRUCTURE; BEHAVIOR AB The effect of heat treatment on the impact behavior of eight experimental heats of reduced-activation ferritic steels was investigated. Steels with 2 1/4, 5, 9, and 12 wt% Cr and containing tungsten, vanadium, and tantalum were examined. Impact properties of steels with 2 1/4 wt% Cr depended on microstructure, which was affected by cooling rate after austenitization. By heat-treating the 2 1/4 wt% Cr steels to change the microstructure from a bainitic structure containing ferrite to one without ferrite, the ductile-brittle transition temperatures were reduced substantially. The cooling rate had essentially no effect on the high-chromium martensitic steels. RP KLUEH, RL (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. OI Maziasz, Philip/0000-0001-8207-334X NR 7 TC 7 Z9 7 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 679 EP 683 DI 10.1016/0022-3115(91)90180-F PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000156 ER PT J AU GRIFFIN, RD GELLES, DS DODD, RA KULCINSKI, GL AF GRIFFIN, RD GELLES, DS DODD, RA KULCINSKI, GL TI PHASE-STABILITY OF A MANGANESE-STABILIZED LOW-ACTIVATION MARTENSITIC STEEL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID MN-CR AB The development of alloys with reduced long-life radioactivity has been incorporated into the goals of fusion materials development. One possible candidate alloy is an Fe-12Cr-6.5Mn-1W-0.3V-0.1C stabilized martensitic steel. The phase stability of this steel has been investigated following neutron irradiation over a temperature range of 420 to 600-degrees-C to doses as high as 100 dpa. The microstructural response of the irradiated steel has been compared to that of the same alloy aged for 10 000 h from 365 to 600-degrees-C. M23C6 was the only carbide found in both the aged and irradiated structures. In the samples aged at 420 and 520-degrees-C, and the samples irradiated at 520-degrees-C, an Fe-Cr-Mn-W chi-phase formed. In the samples irradiated at 420-degrees-C, alpha prime formed. The presence of chi-phase in both the thermally aged and neutron irradiated steels indicates that the Fe-Cr-Mn system is prone to intermetallic phase formation so that careful study of the effects of alloying are needed. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP GRIFFIN, RD (reprint author), UNIV WISCONSIN, INST FUSION TECHNOL, 1500 JOHNSON DR, MADISON, WI 53706 USA. NR 12 TC 0 Z9 0 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 MAR-APR PY 1991 VL 179 BP 714 EP 717 DI 10.1016/0022-3115(91)90188-D PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000164 ER PT J AU SUZUKI, M SAWAI, T MAZIASZ, PJ HISHINUMA, A AF SUZUKI, M SAWAI, T MAZIASZ, PJ HISHINUMA, A TI MICROSTRUCTURAL DEVELOPMENT OF 10CR-2MO FERRITIC STEEL IRRADIATED TO 57 DPA IN HFIR SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Microstructural development under irradiation of the 10Cr-2MoVNb Japanese ferritic/martensitic steel (JFMS) was investigated. Irradiation was performed in the High Flux Isotope Reactor (HFIR) at temperatures that ranged from 400 to 600-degrees-C to doses of up to 57 dpa. Voids were observed only after irradiation at 500-degrees-C to 57 dpa. Chi-phase was formed during the irradiation. The microstructural stability, or chemical composition of thermal precipitates which were produced by tempering (M23C6, M6C) or by thermal aging (Laves phase) were also greatly affected by irradiation. Microcompositional analysis was also able to detect nickel and silicon segregation around helium bubbles. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP SUZUKI, M (reprint author), JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. OI Maziasz, Philip/0000-0001-8207-334X NR 8 TC 4 Z9 4 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 MAR-APR PY 1991 VL 179 BP 718 EP 721 DI 10.1016/0022-3115(91)90189-E PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000165 ER PT J AU KOHNO, Y KOHYAMA, A GELLES, DS AF KOHNO, Y KOHYAMA, A GELLES, DS TI MICROSTRUCTURAL EXAMINATION OF FFTF-IRRADIATED MANGANESE-STABILIZED MARTENSITIC STAINLESS-STEEL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB Transmission electron microscopic examination has been performed on selected TEM disk specimens of manganese-stabilized martensitic stainless steel in order to get identification on the cause of irradiation embrittlement studied by D.S. Gelles and W.L. Hu. Microstructural examination of a specimen irradiated at higher temperature had demonstrated the presence of intermetallic chi-phase known to cause embrittlement. This work indicated that manganese-stabilized steels are prone to intermetallic phase formation which is detrimental to mechanical properties. Ferrite phase was still contained in spite of martensite by manganese addition, and cavity formation was observed and limited within the ferrite phase. This requires further stabilization of the martensitic phase by improved alloy design. C1 PACIFIC NW LAB, DEPT MAT SCI, RICHLAND, WA 99352 USA. RP KOHNO, Y (reprint author), UNIV TOKYO, DEPT MAT SCI, BUNKYO KU, TOKYO 113, JAPAN. NR 3 TC 6 Z9 6 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 MAR-APR PY 1991 VL 179 BP 725 EP 727 DI 10.1016/0022-3115(91)90191-9 PN A PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000167 ER PT J AU KLUEH, RL AF KLUEH, RL TI IRRADIATION HARDENING OF FERRITIC STEELS - EFFECT OF COMPOSITION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID TEMPERATURE TENSILE PROPERTIES; CR-W STEELS; BEHAVIOR AB Irradiation of ferritic steels with neutrons in the temperature range of room temperature to approximately 450-degrees-C results in lattice hardening, which causes an increase in strength and a decrease in ductility. Eight reduced-activation Cr-W-V steels with chromium concentration varying from 2.25 to 12% were irradiated at 365-degrees-C to approximately 7 dpa in the Fast Flux Test Facility. A steel with 2.25% Cr and the combination of 2% W and 0.25% V hardened less than those containing vanadium or tungsten alone or a steel with 1% W and 0.25% V. The amount of hardening was similar for Cr-W-V steels with constant vanadium and tungsten concentrations and containing 2.25, 5, and 9% Cr; a steel with 12% Cr hardened considerably more. Specimens of two conventional Cr-Mo steels, 9Cr-1MoVNb and 12Cr-1MoVW, were also irradiated, and the hardening of these steels was similar to analogous reduced-activation steels. RP KLUEH, RL (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 10 TC 17 Z9 17 U1 1 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 MAR-APR PY 1991 VL 179 BP 728 EP 732 DI 10.1016/0022-3115(91)90192-A PN A PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000168 ER PT J AU KLUEH, RL ALEXANDER, DJ AF KLUEH, RL ALEXANDER, DJ TI IMPACT BEHAVIOR OF 9CR-1MOVNB AND 12CR-1MOVW STEELS IRRADIATED IN HFIR SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID POSTIRRADIATION TENSILE BEHAVIOR; DOPED FERRITIC STEELS; NICKEL CONTENT; TEMPERATURES AB Charpy impact specimens of 9Cr-1MoVNb and 12Cr-1MoVW steels were irradiated in the High Flux Isotope Reactor (HFIR) at 300 and 400-degrees-C to displacement-damage levels as high as 42 dpa. For both steels, irradiation caused large increases in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy (USE). The increase in DBTT and the decrease in USE were greater at 400-degrees-C than at 300-degrees-C. At 400-degrees-C, irradiation to approximately 40 dpa produced shifts in DBTT of 204 and 242-degrees-C for the 9Cr-1MoVNb and 12Cr-1MoVW steels, respectively. These are the largest shifts ever observed for these steels and are attributed to the high helium concentration generated during irradiation in HFIR. RP KLUEH, RL (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 19 TC 26 Z9 26 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 MAR-APR PY 1991 VL 179 BP 733 EP 736 DI 10.1016/0022-3115(91)90193-B PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000169 ER PT J AU LOOMIS, BA SMITH, DL GARNER, FA AF LOOMIS, BA SMITH, DL GARNER, FA TI SWELLING OF NEUTRON-IRRADIATED VANADIUM ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB The swelling of unalloyed vanadium and vanadium alloys containing Cr, Ti, Si, Fe, Zr, W, Mo, and Ni additions was determined after neutron irradiation at 420 and 600-degrees-C to 17-84 dpa in the FFTF-MOTA reactor facility. The swelling of these materials was obtained from a determination of the immersion density of the unirradiated and irradiated materials. The swelling of V is substantially increased by the addition of Cr, and significantly reduced by the addition of Ti. The swelling of V-Cr-Ti alloys is strongly dependent on Ti concentration for Ti concentrations < 3%. For resistance to irradiation-induced swelling, the Ti concentration in a V-Cr-Ti alloy that is to be used as a structural material in a magnetic fusion reactor should be greater than 3%. For these ranges of Ti concentration in a V-Cr-Ti alloy, Cr concentrations of < 15% have minimal effect on the swelling of the alloy. The Vanstar-7 alloy exhibits high (7-10%) swelling on irradiation at 600-degrees-C to 77 dpa. Swelling of V-7.2Cr-14.5Ti, V-13.5Cr-5.2Ti, V-9.2Cr-4.9Ti, V-3.1Ti-(0.3-0.5)Si, and V-17.7Ti on neutron irradiation at 600-degrees-C to 87 dpa is (in % per dpa) 0.10, 0.03, 0.03, 0.01, and 0.01, respectively. C1 ARGONNE NATL LAB, PROGRAM FUSION POWER, ARGONNE, IL 60439 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP LOOMIS, BA (reprint author), ARGONNE NATL LAB, DIV MAT & COMPONENTS TECHNOL, ARGONNE, IL 60439 USA. NR 14 TC 37 Z9 40 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 MAR-APR PY 1991 VL 179 BP 771 EP 774 DI 10.1016/0022-3115(91)90202-I PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000178 ER PT J AU OHNUKI, S GELLES, DS LOOMIS, BA GARNER, FA TAKAHASHI, H AF OHNUKI, S GELLES, DS LOOMIS, BA GARNER, FA TAKAHASHI, H TI MICROSTRUCTURAL EXAMINATION OF SIMPLE VANADIUM ALLOYS IRRADIATED IN THE FFTF/MOTA SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN AB A series of V alloys including pure and impure V and alloys with Mo, W, Cr, Ti and Y have been examined by transmission electron microscopy following irradiation in the FFTF/MOTA to 14 dpa at 870 K. All specimens were found to have developed features typical of radiation damage. Void, dislocation and precipitate structures were different even for specimens of similar composition. However, in general, specimens displayed precipitate development, often indicated by {001} stacking faults. About half of the alloys showed voids. Dislocation structures included large loops and dislocation tangles but much smaller loops similar to black spot damage could be frequently identified. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RP OHNUKI, S (reprint author), HOKKAIDO UNIV, FAC ENGN, SAPPORO, HOKKAIDO 060, JAPAN. NR 9 TC 13 Z9 13 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 MAR-APR PY 1991 VL 179 BP 775 EP 778 DI 10.1016/0022-3115(91)90203-J PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000179 ER PT J AU LOOMIS, BA SMITH, DL AF LOOMIS, BA SMITH, DL TI RESPONSE OF UNIRRADIATED AND NEUTRON-IRRADIATED VANADIUM ALLOYS TO CHARPY-IMPACT LOADING SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article; Proceedings Paper CT 4TH INTERNATIONAL CONF ON FUSION REACTOR MATERIALS ( ICFRM-4 ) CY DEC 04-08, 1989 CL KYOTO, JAPAN ID SELECTION AB The ductile-brittle transition temperature (DBTT) was determined by Charpy-impact tests for dehydrogenated (< 30 appm H) and hydrogenated (400-1200 appm H) V-7.2Cr-14.5Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, V-17.7Ti, V-9.2Cr-4.9Ti, V-9.0Cr-3.2Fe-1.2Zr, V-3.1Ti-0.5Si, V-4.1Cr-4.3Ti, V-4.6Ti, and V-2.5Ti-1.0Si alloys. The DBTT was also determined for V-13.5Cr-5.2Ti, V-9.2Cr-4.9Ti, V-7.2Cr-14.5Ti, and V-17.7Ti alloys after neutron irradiation at 420 and 600-degrees-C to 41-44 dpa. The DBTTs determined for these vanadium alloys show that a vanadium alloy containing Cr and/or Ti and Si alloying additions to be used as a structural material in a fusion reactor should contain 3-9 wt% total alloying addition for maximum resistance to hydrogen- and/or irradiation-induced embrittlement. C1 ARGONNE NATL LAB,FUSION POWER PROGRAM,ARGONNE,IL 60439. RP LOOMIS, BA (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 8 TC 11 Z9 11 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 MAR-APR PY 1991 VL 179 BP 783 EP 786 DI 10.1016/0022-3115(91)90205-L PN A PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR770 UT WOS:A1991FR77000181 ER PT J AU FISCHER, AK JOHNSON, CE AF FISCHER, AK JOHNSON, CE TI DESORPTION OF H2O AND H2 FROM STEEL AND LIALO2 BY TEMPERATURE PROGRAMMED DESORPTION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID ADSORPTION AB Temperature programmed desorption (TPD) measurements with a steel sample tube and helium sweep gas are in progress to provide data describing the kinetics of desorption of H2O(g) and H2(g) from ceramic tritium breeders. Preliminary blank experiments indicated that the steel can be a reactive participant with H2O being consumed and H-2 being evolved. There is also evidence of some dissolution of H-2 in the steel. However, it is possible to stabilize the steel in the absence of added H-2 so that useful desorption measurements with H2O(g) can be made. Initial work was on the LiAlO2-H2O(g) system. Fresh samples of LiAlO2 bear large amounts of adsorbed H2O. TPD spectra were measured for LiAlO2 that had been equilibrated in a helium stream with 200 ppm H2O(g) at temperatures from 473 to 773 K. Several techniques of data analysis were applied. questions of possible peak overlap still remain to be resolved. An activation energy for desorption of H2O(g) of approximately 120 kJ/mol appears to be associated with the sample equilibrated at 673 K. This result agrees with the value reported in the literature for decomposition of LiOH, and suggests that some sites on LiAlO2 might resemble sites on Li2O in their adsorptive properties. For a 773 K equilibration, the activation energy of desorption appears considerably higher. RP FISCHER, AK (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439, USA. NR 6 TC 7 Z9 7 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 MAR-APR PY 1991 VL 179 BP 812 EP 815 DI 10.1016/0022-3115(91)90212-P PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200006 ER PT J AU KOPASZ, JP TAM, SW JOHNSON, CE AF KOPASZ, JP TAM, SW JOHNSON, CE TI ENHANCED TRITIUM TRANSPORT AND RELEASE BY SOLIDS MODIFICATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DIFFUSION; CONDUCTIVITY; OXIDES AB In order to improve the tritium release characteristics of lithium ceramics, we are investigating the effects of dopants on tritium transport and release. Prior work has suggested a correlation between tritium and lithium diffusion in lithium-containing ceramics. This correlation has led us to propose a mechanism for tritium diffusion in which the tritium diffuses in the form of a lithium-vacancy/tritium complex. If this is the case, one should be able to increase the tritium diffusivity by increasing the number of lithium vacancies and thereby increasing the number of lithium-vacancy/tritium complexes. The size of the increase in the diffusivity, however, will be dependent upon several parameters, including the binding energy of the lithium-vacancy/tritium complex. Our calculations indicate that, under conditions comparable to those in some in-pile irradiation experiments, a binding energy of around 84 kJ/mol should increase the diffusivity and lead to a decrease in the steady-state tritium inventory by about a factor of six. RP KOPASZ, JP (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 13 TC 8 Z9 9 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 MAR-APR PY 1991 VL 179 BP 816 EP 819 DI 10.1016/0022-3115(91)90213-Q PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200007 ER PT J AU HULL, AB CHOPRA, OK LOOMIS, B SMITH, D AF HULL, AB CHOPRA, OK LOOMIS, B SMITH, D TI COMPATIBILITY BETWEEN VANADIUM-BASE ALLOYS AND FLOWING LITHIUM - PARTITIONING OF HYDROGEN AT ELEVATED-TEMPERATURES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID LIQUID AB A major concern in fusion reactor design is possible hydrogen-isotope-induced embrittlement of structural alloys in the neutron environment expected in these reactors. Hydrogen fractionation occurs between lithium and various refractory metals according to a temperature-dependent distribution coefficient, K(H), that is defined as the ratio of the hydrogen concentration in the metallic specimen to that in the liquid lithium. In the present work, K(H) was determined for pure vanadium and several binary (V-10Cr, V-15Cr, V-5Ti, V-15Ti, V-20Ti, V-30Ti) and ternary alloys (V-10Cr-5Ti, V-15Cr-1Ti, V-15Cr-5Ti, V-3Ti-0.5Si), and the commercial Vanstar 7 (V-10Cr-3Fe-1Zr). Hydrogen distribution studies were performed in an austenitic steel forced-circulation lithium loop. Equilibium concentrations of hydrogen in vanadium-base alloys exposed to flowing lithium at temperatures of 350 to 550-degrees-C were measured by inert gas fusion techniques and residual gas analysis. Thermodynamic calculations are consistent with the effect of chromium and titanium in the alloys on the resultant hydrogen fractionation. Experimental and calculated results indicate that K(H) values are very low; i.e., the hydrogen concentrations in the lithium-equilibrated vanadium-base alloy specimens are about two orders of magnitude lower than those in the lithium. Because of this low distribution coefficient, embrittlement of vanadium alloys by hydrogen in lithium would not be expected. C1 ARGONNE NATL LAB,FUS POWER PROGRAM,ARGONNE,IL 60439. RP HULL, AB (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 13 TC 2 Z9 2 U1 1 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 MAR-APR PY 1991 VL 179 BP 824 EP 826 DI 10.1016/0022-3115(91)90215-S PN B PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200009 ER PT J AU ROUX, N BRIEC, M BRUET, M FLAMENT, T JOHNSON, C MASSON, M TERLAIN, A TOURNEBIZE, F AF ROUX, N BRIEC, M BRUET, M FLAMENT, T JOHNSON, C MASSON, M TERLAIN, A TOURNEBIZE, F TI THE SIBELIUS EXPERIMENT - STUDY OF THE IRRADIATION BEHAVIOR OF BERYLLIUM/CERAMIC AND BERYLLIUM/STEEL COMPACTS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Sibelius is an in-reactor compatibility test of beryllium and ceramics i.e., Be/Li2O, Be/LiAlO2, Be/Li4SiO4, Be/Li2ZrO3, and beryllium and steels i.e., Be/316L, Be/1.4914 (martensitic steel) conducted in the core of the Siloe reactor at Grenoble. The experiment is run for four cycles (approximately 80 days) at a temperature of 550-degrees-C. Effect of neutron irradiation on compatibility is identified by comparison with out-of-reactor tests carried out in identical conditions. By monitoring the tritium release characteristics from the compatibility specimens and comparing with check samples containing only ceramics, one can quickly obtain information on certain reactions. Extensive post-irradiation examination will be performed in the USA, CEA and KFK laboratories to evaluate: (1) corrosion at the beryllium/ceramic interface; (2) corrosion at the beryllium/steel interface; (3) retention of tritium and helium in ceramics; (4) retention of tritium and helium in beryllium; and (5) swelling of beryllium. C1 CEN,CEA,IRDI,F-38041 GRENOBLE,FRANCE. CEN,CEA,IRDI,F-92265 FONTENAY ROSES,FRANCE. ARGONNE NATL LAB,ARGONNE,IL 60439. RP ROUX, N (reprint author), CENS,CEA,IRDI,F-91191 GIF SUR YVETTE,FRANCE. NR 4 TC 10 Z9 10 U1 1 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 MAR-APR PY 1991 VL 179 BP 827 EP 830 DI 10.1016/0022-3115(91)90216-T PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200010 ER PT J AU SLAGLE, OD HOLLENBERG, GW BALDWIN, DL AF SLAGLE, OD HOLLENBERG, GW BALDWIN, DL TI THE FUBR-1B IRRADIATION EXPERIMENT - TRITIUM RELEASE AND PHYSICAL STABILITY OF SOLID BREEDER MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The FUBR-1B irradiation experiment in EBR-II has provided important information on the irradiation behavior of candidate lithium solid breeder materials in a high neutron spectrum. The solid breeder materials include Li2O, LiAlO2, Li1ZrO3, Li8ZrO6 and Li4SiO4 pellets and LiAlO2 spheres. The irradiation behavior of the materials was characterized for the temperature range from 400 to 900-degrees-C. The amount of tritium retained by the solid breeder materials, as well as swelling and physical stability, was determined for specimens removed after the first period of irradiation. LiAlO2, Li2ZrO3, and Li8ZrO6 exhibited excellent dimensional stability during irradiation while the dimensional stability of Li2O was found be dependent on the microstructure. The amount of retained tritium is compared to similar closed capsule experiments and extends the data to burnups as high as 1.6 x 10(21) at/cc. RP SLAGLE, OD (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 6 TC 8 Z9 9 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 MAR-APR PY 1991 VL 179 BP 843 EP 846 DI 10.1016/0022-3115(91)90220-2 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200014 ER PT J AU TAM, SW WRIGHT, J CURTISS, LA JOHNSON, CE AF TAM, SW WRIGHT, J CURTISS, LA JOHNSON, CE TI INVESTIGATIONS OF HYDROGEN/LI2O SURFACE INTERACTIONS VIA QUANTUM CHEMICAL CLUSTER-METHODS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Both in-pile and out-of-pile tritium release experiments on solid breeder ceramics have indicated that the presence of hydrogen in the purge gas significantly enhances the tritium release rate. To provide an understanding of this phenomenon we have undertaken a series of theoretical investigations into the interaction of a hydrogen molecule with Li2O surfaces. Two complementary quantum chemical cluster methods, i.e., the extended Huckel (EH) and the Ab Initio (AI) approaches have been utilized. The partially covalent nature of the interaction dictates the necessity of a quantum mechanical approach. We have examined the issues of binding energetics, favored adsorption sites and the degree of charge transfer. Basing on these calculations the nature of the interaction of H2/Li2O surfaces has been analyzed. As far as the authors are aware this represents the first time that these issues for this system (which is of crucial importance for fusion technology) have been addressed on such a comprehensive quantum mechanical basis. Implications for the interpretation of tritium release experiments would be addressed. RP TAM, SW (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 859 EP 862 DI 10.1016/0022-3115(91)90224-U PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200018 ER PT J AU HEINISCH, HL SINGH, BN AF HEINISCH, HL SINGH, BN TI THE MORPHOLOGY OF COLLISION CASCADES AS A FUNCTION OF RECOIL ENERGY SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DISPLACEMENT CASCADES; COMPUTER-SIMULATION; IRRADIATION AB An analytical method based on defect densities has been devised to determine the threshold energies for subcascade formation in computer simulated collision cascades. Cascades generated with the binary collision code MARLOWE in Al, Cu, Ag, Au, Fe, Mo and W were analyzed to determine the threshold energy for subcascade formation, the number of subcascades per recoil per unit energy and the average spacing of subcascades. Compared on the basis of reduced damage energy, metals of the same crystal structure have subcascade thresholds at the same reduced energy. The number of subcascades per unit reduced damage energy is about the same for metals of the same crystal structure, and the average spacing of subcascades is about the same in units of lattice parameters. Comparisons between subcascade threshold energies and average recoil energies in fission and fusion neutron environments show the spectral sensitivity of the formation of subcascades. C1 RISO NATL LAB, DK-4000 ROSKILDE, DENMARK. RP HEINISCH, HL (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 12 TC 11 Z9 11 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 MAR-APR PY 1991 VL 179 BP 893 EP 896 DI 10.1016/0022-3115(91)90232-V PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200026 ER PT J AU HORSEWELL, A SINGH, BN PROENNECKE, S SOMMER, WF HEINISCH, HL AF HORSEWELL, A SINGH, BN PROENNECKE, S SOMMER, WF HEINISCH, HL TI DEFECT STRUCTURES IN COPPER AND GOLD IRRADIATED WITH FAST-NEUTRONS, 14 MEV NEUTRONS AND 600-800 MEV PROTONS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Copper and Gold have been irradiated with fast neutrons (mixed spectrum thermal reactor), 14 MeV neutrons (RTNS-II) and 600-800 MeV protons (PIREX II and LAMPF) at 300-373 K over a dose range of 10(20)-10(24) particles/m2. Defect cluster concentrations and sizes have been obtained by transmission electron microscopy. The variation in cascade damage structures resulting from a change in average recoil energy from 10(4) to 10(6) eV is shown. C1 PAUL SCHERRER INST, CH-5232 VILLIGEN, SWITZERLAND. UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP HORSEWELL, A (reprint author), RISO NATL LAB, DEPT MET, DK-4000 ROSKILDE, DENMARK. OI Horsewell, Andy/0000-0003-4297-2564 NR 4 TC 23 Z9 23 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 924 EP 927 DI 10.1016/0022-3115(91)90240-8 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200034 ER PT J AU FUKUSHIMA, H SHIMOMURA, Y GUINAN, MW HAHN, PA KIRITANI, M AF FUKUSHIMA, H SHIMOMURA, Y GUINAN, MW HAHN, PA KIRITANI, M TI ANNEALING EXPERIMENTS OF LOW-TEMPERATURE 14 MEV NEUTRON-IRRADIATED ORDERED AND DISORDERED CU3AU BY TEM SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DISPLACEMENT CASCADE DAMAGE AB Annealing experiments using a liquid-He cryotransfer TEM holder were performed for ordered and disordered Cu3Au irradiated to (5-9)x 10(20) n/m2 with 14 MeV neutrons below 20 K. Almost all TEM-observed defect clusters in a thicker part of disordered Cu3Au were of the interstitial-type, and a significant fraction of those in a thicker part of ordered Cu3Au were expected to be interstitial-type. The mean image diameter of defect clusters in ordered Cu3Au was larger than that in disordered Cu3Au. The possible reason is the lack of long-range focusing along the [110] Cu chains in disordered Cu3Au, which results in a higher cascade temperature and a higher probability of vacancy-interstitial recombination in disordered Cu3Au than in ordered Cu3Au. Because of stage-III annealing, TEM-visible interstitial-type defect clusters started to be annealed out at around 250 K, and superlattice reflections were observed in disordered Cu3Au after room temperature annealing. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NAGOYA UNIV,DEPT NUCL ENGN,CHIKUSA KU,NAGOYA,AICHI 464,JAPAN. RP FUKUSHIMA, H (reprint author), HIROSHIMA UNIV,FAC ENGN,HIROSHIMA 724,JAPAN. NR 16 TC 4 Z9 4 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 MAR-APR PY 1991 VL 179 BP 943 EP 946 DI 10.1016/0022-3115(91)90245-3 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200039 ER PT J AU WOO, CH SINGH, BN HEINISCH, HL AF WOO, CH SINGH, BN HEINISCH, HL TI DIFFUSION-BASED EVALUATION OF DEFECT PROCESSES IN CASCADE ZONES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB In order to understand the radiation effects under cascade damage conditions where vacancies and interstitials are created in a localized and segregated fashion, a programme has been initiated to model the evolution of point defect microstructure between cascades and among subcascades. The model and some preliminary results are presented of analytical and numerical calculations of the space and time dependent diffusion and clustering of self-interstitial atoms. The calculation includes the effect of back diffusion of self-interstitial atoms to the vacancy-rich cascade core. It is concluded that a diffusion-rate theory model of the point defect evolution in cascade zones appears to be computationally feasible. C1 RISO NATL LAB, DEPT MET, DK-4000 ROSKILDE, DENMARK. PACIFIC NW LAB, FUS MAT PROGRAM, RICHLAND, WA 99352 USA. RP WOO, CH (reprint author), ATOM ENERGY CANADA LTD, ADV MAT BRANCH, PINAWA R0E 1L0, MANITOBA, CANADA. RI Woo, Chung Ho/E-3657-2010 NR 8 TC 6 Z9 6 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 MAR-APR PY 1991 VL 179 BP 951 EP 953 DI 10.1016/0022-3115(91)90247-5 PN B PG 3 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200041 ER PT J AU KOJIMA, S ZINKLE, SJ HEINISCH, HL AF KOJIMA, S ZINKLE, SJ HEINISCH, HL TI RADIATION HARDENING IN NEUTRON-IRRADIATED POLYCRYSTALLINE COPPER - BARRIER STRENGTH OF DEFECT CLUSTERS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID MICROSTRUCTURE; CRYSTALS AB Defect cluster formation in 14-MeV neutron irradiated polycrystalline copper has been observed by transmission electron microscopy (TEM) and correlated with the increase in yield stress. The measurements indicate that the radiation hardening component of the yield strength in polycrystals is not directly additive to the unirradiated yield strength. A transitional behavior was observed for radiation hardening at low fluences, which produces an anomalous variation of the defect cluster barrier strength with fluence. The behavior is attributed to the effect of grain boundaries on slip band transmission. An upper limit for the room temperature barrier strength of defect clusters in neutron-irradiated copper was determined to be alpha = 0.23. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. OI Zinkle, Steven/0000-0003-2890-6915 NR 25 TC 25 Z9 26 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 MAR-APR PY 1991 VL 179 BP 982 EP 985 DI 10.1016/0022-3115(91)90255-6 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200049 ER PT J AU ZINKLE, SJ FARRELL, K KANAZAWA, H AF ZINKLE, SJ FARRELL, K KANAZAWA, H TI MICROSTRUCTURE AND CAVITY SWELLING IN REACTOR-IRRADIATED DILUTE COPPER-BORON ALLOY SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB An initial microstructural examination has been performed on copper specimens containing approximately 18 wt ppm B-10 that were irradiated with fission neutrons to approximately 1.2 dpa at a damage rate of 2 x 10(-7) dpa/s. A bimodal size distribution of cavities was observed for the irradiation temperatures of 182 through 500-degrees-C, along with dislocation loops and stacking fault tetrahedra (SFT). C1 JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. RP ZINKLE, SJ (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. OI Zinkle, Steven/0000-0003-2890-6915 NR 14 TC 30 Z9 30 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 MAR-APR PY 1991 VL 179 BP 994 EP 997 DI 10.1016/0022-3115(91)90258-9 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200052 ER PT J AU KISHIMOTO, N CLAUSING, RE HEATHERLY, L FARRELL, K AF KISHIMOTO, N CLAUSING, RE HEATHERLY, L FARRELL, K TI HELIUM GAS-RELEASE DUE TO GRAIN-BOUNDARY FRACTURE IN NEUTRON-IRRADIATED HIGH-NICKEL AUSTENITIC ALLOYS AND A FERRITIC STEEL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB To examine influence of helium on irradiation-induced embrittlement, helium gas release on brittle fracture has been investigated for high-nickel precipitation-strengthened alloys D21, D25 and a ferritic steel HT-9, irradiated in EBR-II to the fluence of 3 x 10(26) n/m2 (E > 0.1 MeV), using a quadrupole massfilter in the ultra-high-vacuum fracture system. The irradiated alloys, D21 and D25, fractured intergranularly (T(test) = RT) and released considerable amounts of helium on fracture. From the observed helium release, the helium population segregated on the grain boundary was estimated to be a few percent of the metallic atoms there (1000-2000 times the average helium density approximately 15 ppm). The HT-9 (T(test) = 77 K) showed a similar concentration ratio in spite of the small helium content in average (approximately 1 ppm). The result suggests that the segregated helium may contribute to the embrittlement, as well as the brittle phase formation along the grain boundaries bubble formation. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP KISHIMOTO, N (reprint author), NATL RES INST MET,TSUKUBA LABS,SENGEN 1-2-1,TSUKUBA,IBARAKI 305,JAPAN. NR 9 TC 2 Z9 2 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 MAR-APR PY 1991 VL 179 BP 998 EP 1002 DI 10.1016/0022-3115(91)90259-A PN B PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200053 ER PT J AU KAMEDA, J MAO, X BEVOLO, AJ AF KAMEDA, J MAO, X BEVOLO, AJ TI INTERGRANULAR IMPURITY SEGREGATION AND EMBRITTLEMENT IN NEUTRON-IRRADIATED IRON-ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID FRACTURE MODE AB Intergranular solute segregation and embrittlement induced during neutron irradiation (9.4 x 10(22) n/m2 at 668 K) in iron alloys doped with copper (Cu), phosphorus (P) and/or carbon (C) have been investigated using small punch (SP) test techniques and scanning Auger microscopy (SAM). It was found that Cu and/or P containing alloys exhibited a greater effect of irradiation on hardening than C-containing alloys. The neutron irradiation increased more greatly the ductile-brittle transition temperature (DBTT) in the Cu-doped alloy compared with the other alloys. Intergranular and transgranular fracture occurred in the alloys without and with C, respectively. The neutron irradiation did not change the fracture mode. Fracture surface SAM analyses demonstrated that while the neutron irradiation enhanced S-segregation in the Cu-doped alloy without P-segregation, it decreased S-segregation and increased P-segregation in the P-containing alloys. The relationship of neutron irradiation-induced intergranular solute segregation to embrittlement is discussed. RP KAMEDA, J (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 9 TC 6 Z9 6 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 MAR-APR PY 1991 VL 179 BP 1034 EP 1037 DI 10.1016/0022-3115(91)90268-C PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200062 ER PT J AU NISHIGUCHI, R SHIMOMURA, Y HAHN, PA GUINAN, MW KIRITANI, M AF NISHIGUCHI, R SHIMOMURA, Y HAHN, PA GUINAN, MW KIRITANI, M TI COMPARISON OF PKA ENERGY-SPECTRA, GAS-ATOM PRODUCTION AND DAMAGE ENERGY DEPOSITION IN NEUTRON-IRRADIATION AT VARIOUS FACILITIES SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB By dividing neutron-energy spectrum into four energy groups, (I) < 10 eV, (II) 10 eV to 0.1 MeV, (III) 0.1 MeV to 10 MeV and (IV) > 10 MeV, contributions to damage parameters (PKA spectrum, damage energy and gas-atom production) from each of the energy group were calculated for neutron irradiations at various facilities with the SPECTER code developed by Greenwood and Smither [1]. The normalized PKA spectra and the gas-atom productions were compared to examine differences in damage parameters. Such comparisons were carried out among (1) irradiations at various positions in different fission reactors (i.e. KUR, JOYO and FFTF-MOTA), and among (2) those at various fission reactors. Damage parameters were also calculated at STARFIRE fusion reactor and RTNS-II. A possible method to correlate damages at different fission reactors is discussed. It is suggested that damages in fusion reactor can be simulated by the superposition of irradiations with fission and D-T neutrons. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NAGOYA UNIV,FAC ENGN,DEPT NUCL ENGN,CHIKUSA KU,NAGOYA,AICHI 464,JAPAN. RP NISHIGUCHI, R (reprint author), HIROSHIMA UNIV,FAC ENGN,HIROSHIMA 724,JAPAN. NR 5 TC 3 Z9 3 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 1073 EP 1077 DI 10.1016/0022-3115(91)90278-F PN B PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200072 ER PT J AU YOSHIDA, N HEINISCH, HL MUROGA, T ARAKI, K KIRITANI, M AF YOSHIDA, N HEINISCH, HL MUROGA, T ARAKI, K KIRITANI, M TI MICROSTRUCTURE-TENSILE PROPERTY CORRELATION OF 316 SS IN LOW-DOSE NEUTRON IRRADIATIONS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB Annealed 316 SS was irradiated at 90 and 290-degrees-C in RTNS-II and in OWR. Radiation induced microstructures were examined by a transmission electron microscope. Very small dislocation loops of extremely high density were observed in dark field images. In the case of 90 and 290-degrees-C irradiations at RTNS-II and of 90-degrees-C irradiation at OWR, the loop density increased moderately with the dpa (roughly proportional to the square root of dpa), while that of 290-degrees-C irradiation at OWR showed a stronger dpa dependence above 0.003 dpa, where the yield stress change DELTA-sigma-y also increased strongly. DELTA-sigma-y was roughly proportional to the square root of the defect density and was independent of the irradiation temperature and the neutron energy spectrum. The observed small dislocation loops were the origin of the yield stress change; the strength parameter was estimated to be 0.2. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. NAGOYA UNIV, FAC ENGN, DEPT NUCL ENGN, NAGOYA, AICHI 464, JAPAN. RP YOSHIDA, N (reprint author), KYUSHU UNIV, APPL MECH RES INST, KASUGA, FUKUOKA 816, JAPAN. RI U-ID, Kyushu/C-5291-2016; Kyushu, RIAM/F-4018-2015 NR 10 TC 17 Z9 17 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 MAR-APR PY 1991 VL 179 BP 1078 EP 1082 DI 10.1016/0022-3115(91)90279-G PN B PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200073 ER PT J AU TAKEHANA, S HAKOZAKI, K GUINAN, MW MATSUI, H AF TAKEHANA, S HAKOZAKI, K GUINAN, MW MATSUI, H TI MAGNETIC STUDY OF DEFECTS IN IRON INDUCED BY 14 MEV NEUTRON-IRRADIATION SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID TEMPERATURE ELECTRON-IRRADIATION AB A series of magnetic disaccommodation measurements has been performed using high-purity iron polycrystals after irradiation with fission or fusion neutrons at 20 K. Several peaks were observed after successive annealing. A peak at 110 K and another at 200 K recovers in the peak temperature range. The mechanisms responsible for these processes are discussed as well as the difference between fission and fusion neutron and electron irradiation. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP TAKEHANA, S (reprint author), TOHOKU UNIV,INST MAT RES,SENDAI,MIYAGI 980,JAPAN. NR 11 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 1092 EP 1095 DI 10.1016/0022-3115(91)90282-C PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200076 ER PT J AU HOYT, JJ GARNER, FA AF HOYT, JJ GARNER, FA TI THE SOLUTE DEPENDENCE OF BIAS FACTORS IN IRRADIATED FE-NI ALLOYS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID AUSTENITIC STAINLESS-STEELS; THERMOCHEMICAL EQUILIBRIUM; VOID NUCLEATION; LINEAR THEORY; SOLIDS; STRESS; DIFFUSION AB The interstitial and vacancy biases for an edge dislocation in a binary alloy were examined, assuming the existence of an equilibrium Cottrell atmosphere around the line defect. The larche and Cahn treatment of stress relaxation due to a solute atmosphere was employed with the Wolfer and Ashkin formulation for the bias of an edge dislocation to compute the bias as a function of nickel concentration in the Fe-Ni system. Using the minimum critical void radius concept, the concentration-dependent bias offers a plausible explanation for the minimum in swelling observed at intermediate nickel levels and the gradual increase in swelling at higher nickel levels. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP HOYT, JJ (reprint author), WASHINGTON STATE UNIV, DEPT MECH & MAT ENGN, PULLMAN, WA 99164 USA. NR 22 TC 8 Z9 8 U1 1 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 MAR-APR PY 1991 VL 179 BP 1096 EP 1099 DI 10.1016/0022-3115(91)90283-D PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200077 ER PT J AU HAHN, PA GUINAN, MW SUMMERS, LT OKADA, T SMATHERS, DB AF HAHN, PA GUINAN, MW SUMMERS, LT OKADA, T SMATHERS, DB TI FUSION NEUTRON-IRRADIATION EFFECTS IN COMMERCIAL NB3SN SUPERCONDUCTORS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID HARD SUPERCONDUCTORS; FLUX AB This is a preliminary report on a series of fusion neutron (14.8 MeV) irradiation studies on pure and alloyed multifilamentary Nb3Sn superconductors at the Livermore Rotating Target Neutron Source RTNS-II. One set of specimens (2 pure Nb3Sn and one alloyed - (Nb-1.2 wt% Ti)3Sn - conductor) was irradiated in-situ at 14 K in 3 cycles up to a maximum fluence of 1.3 x 10(22) n/m2 (0.32 eV deposited damage energy) and T(c) and j(c) measured in magnetic fields up to 15.5 T. The critical parameters were also recorded after isochronal annealing cycles at 80, 180 and 300 K. Six identical sets including 3 additional wires (one pure liquid diffusion processed and 2 alloyed - (Nb-0.8 wt% Ti)3Sn and (Nb-2.0 wt% Ti)3Sn - conductors) were irradiated at room temperature at different positions from the source in order to accumulate approximately 2x, 1x, 1/2, 1/4, 1/8 and 1/16 of the maximum dose of the in-situ experiment. A comparison of the in-situ results with the room temperature irradiation data showed no significant differences in the behaviour of T(c) and j(c) as a function of neutron fluence and only small recovery effects were found after the isochronal anneals at the end of the in-situ experiment. C1 OSAKA UNIV,INST SCI & IND RES,IBARAKI,OSAKA 59004,JAPAN. TELEDYNE WAH CHANG CORP,ALBANY,OR 97321. RP HAHN, PA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 26 TC 7 Z9 7 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 MAR-APR PY 1991 VL 179 BP 1127 EP 1130 DI 10.1016/0022-3115(91)90290-N PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200084 ER PT J AU SMITH, DL DAENNER, W KALININ, G YOSHIDA, H AF SMITH, DL DAENNER, W KALININ, G YOSHIDA, H TI ITER RESEARCH-AND-DEVELOPMENT ON BREEDER BLANKET MATERIALS SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The International Thermonuclear Experimental Reactor (ITER) activity includes specific R&D in critical areas to support the ITER design. Several of the critical tasks defined as part of the ITER validating R&D are materials related. This paper presents a summary of the breeder/blanket materials related R&D conducted by the four participating parties; viz., European Community, Japan, Soviet Union and the United States. The current effort includes several subtasks in each of the following four task areas: (i) ceramic breeder materials, (2) lead-lithium breeder, (3) aqueous salt solutions, (4) neutron multiplier materials. The objective and scope of each subtask is stated. Although this work was initiated in late 1988, important results have been obtained in all four areas. The work on ceramic breeders includes properties measurements, compatibility studies, and tritium recovery experiments with Li2O and selected ternary ceramics. Investigations on the lead-lithium breeder have focused primarily on properties, compatibility, and tritium extraction from the 17L-83Pb eutectic alloy. The work on the aqueous salt breeders includes corrosion, solution chemistry, and radiolysis effects in a radiation environment. Investigations defined under the neutron multiplier task are focused on beryllium; however, lead in the lithium lead alloy also serves as a neutron multiplier. The schedule and planned future work in each area are summarized. C1 SCI RES & DESIGN INST POWER ENGN,MOSCOW 107113,USSR. MAX PLANCK INST PLASMA PHYS,NET TEAM,W-8046 GARCHING,GERMANY. JAPAN ATOM ENERGY RES INST,TRITIUM PROC LAB,TOKAI,IBARAKI 31911,JAPAN. RP SMITH, DL (reprint author), ARGONNE NATL LAB,FUS POWER PROGRAM,9700 S CASS AVE,ARGONNE,IL 60439, 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 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD MAR-APR PY 1991 VL 179 BP 1185 EP 1188 DI 10.1016/0022-3115(91)90318-2 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200094 ER PT J AU SEKI, M GUSEVA, M VIEIDER, G WHITLEY, J AF SEKI, M GUSEVA, M VIEIDER, G WHITLEY, J TI ITER RELATED RESEARCH-AND-DEVELOPMENT ON LOW-Z PLASMA-FACING MATERIALS FOR DIVERTOR AND 1ST WALL SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article AB The current status and recent outcomes of the ITER related R&D on low-Z plasma-facing materials are reviewed, with particular emphasis being placed on carbon-based materials. Data needs are critical in the area of irradiation effects, erosion due to disruptions, sputtering and redeposition, and component-related issues. Neutron irradiation tests using fission reactors are in progress. Data so far obtained show that the effect on dimensional changes of C/C's depends markedly on materials. As for erosion due to disruptions, laboratory experiments of short pulse heating indicate that the erosion of carbon materials is much larger than numerically predicted. Chemical sputtering is suppressed by adding boron or titanium to carbon. Concerning the component related R&D, brazing of carbon materials to metal has been successfully done. Divertor and first wall mock-ups are being manufactured for high heat flux testing. C1 IV KURCHATOV ATOM ENERGY INST,MOSCOW,USSR. MAX PLANCK INST PLASMA PHYS,ITER TEAM,W-8046 GARCHING,GERMANY. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP SEKI, M (reprint author), JAPAN ATOM ENERGY RES INST,NAKA FUS RES ESTAB,NAKA,IBARAKI 31101,JAPAN. NR 0 TC 1 Z9 1 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 MAR-APR PY 1991 VL 179 BP 1189 EP 1192 DI 10.1016/0022-3115(91)90319-3 PN B PG 4 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA FR772 UT WOS:A1991FR77200095 ER PT J AU BAN, S SETLOW, RB EZAKI, H HIRAOKA, T YAMANE, M NISHIKI, M DOHI, K AF BAN, S SETLOW, RB EZAKI, H HIRAOKA, T YAMANE, M NISHIKI, M DOHI, K TI X-RAY-SENSITIVITY OF FIBROBLAST CELL STRAINS DERIVED FROM ATOMIC-BOMB SURVIVORS WITH AND WITHOUT BREAST-CANCER SO JOURNAL OF RADIATION RESEARCH LA English DT Article DE A-BOMB SURVIVORS; BREAST CANCER; SKIN FIBROBLASTS; CLONOGENIC ASSAY; SENSITIVITY ID RADIOSENSITIVITY AB Fibroblasts were established in vitro from skin biopsies obtained from 55 women and 1 man with or without breast cancer and with or without exposure to radiations from the atomic bomb (A-bomb) explosion in Hiroshima. The radiosensitivity of these cells was evaluated by clonogenic assays after exposure to X rays. Dose-response curves were fitted to a multitarget model, S/S0 = A[1-(1-e(-D/D)0)N]. There was no difference in the means or variances of radiosensitivity between exposed and nonexposed groups, or between groups with and without breast cancer. C1 TSUCHIYA HOSP,DEPT SURG,NAKA KU,HIROSHIMA 730,JAPAN. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. HIROSHIMA UNIV,SCH MED,DEPT INTERNAL MED 2,MINAMI KU,HIROSHIMA 734,JAPAN. RP BAN, S (reprint author), RADIAT EFFECTS RES FDN,DEPT GENET,HIJIYAMA PK 5-2,MINAMI KU,HIROSHIMA 732,JAPAN. NR 12 TC 3 Z9 3 U1 0 U2 0 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD MAR PY 1991 VL 32 SU S BP 330 EP 338 DI 10.1269/jrr.32.SUPPLEMENT_330 PG 9 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA GE293 UT WOS:A1991GE29300039 PM 1762123 ER PT J AU STEIN, CL KRUMHANSL, JL KIMBALL, KM AF STEIN, CL KRUMHANSL, JL KIMBALL, KM TI SILICATE DIAGENESIS IN THE SALADO FORMATION, SOUTHEASTERN NEW-MEXICO SO JOURNAL OF SEDIMENTARY PETROLOGY LA English DT Article ID PALO-DURO BASIN; FLUID INCLUSIONS; EVAPORITES; ROCKS; TEXAS; GEOCHEMISTRY; EVAPORATION; RECOGNITION; FELDSPARS; SEAWATER AB In the Salado Formation, a thick evaporite sequence in the Permian Delaware Basin of southeastern New Mexico, primary detrital silicates such as feldspars, quartz and clay minerals have undergone significant diagenetic alteration. Seventy-five samples were collected from argillaceous partings in the lower Salado Formation halite facies, at the stratigraphic level of the Waste Isolation Pilot Plant (WIPP). These were compared with twenty-eight samples from cores of the Vaca Triste member of the Salado, a thin clastic unit at the top of the McNutt potash zone, and with a clay-rich sample from the lower contact of the Culebra Dolomite (in the overlying Rustler Formation). The purpose of this comparison was to evaluate the influence of brine chemistry (i.e., halite and potash facies, normal to hypersaline marine conditions) and sediment composition (clays, sandy silt, dolomitized limestone) on diagenetic processes. X-ray diffraction analyses and electron microscopy identified a clay similar to corrensite from all three stratigraphic horizons. Authigenic quartz and potassium feldspar were found in both Vaca Triste samples and in those from the WIPP. The feldspar occurred in greater abundance in the Vaca Triste samples than in those from the WIPP horizon. Fluid inclusion compositions from halite in the Vaca Triste were compared with those from the WIPP repository horizon. The solution speciation/mineral solubility code EQ3NR was used to calculate ionic activities of relevant species in WIPP and Vaca Triste brines. For these high ionic strength Salado Formation brines, the activity coefficients calculated by this code must be qualified. However, the assumed pH and the computed activities of K+ and Mg+2 correctly predict a mineralogy that is consistent with our observations of mixed-layer, Mg-rich, corrensite-like clays and microcline. EQ3NR predicts that the WIPP horizon fluid compositions are at or above saturation with respect to minerals characteristic of the halite facies: halite, aragonite, dolomite, magnesite, and huntite. Application of EQ3NR to the Vaca Triste fluid inclusions indicates saturation or supersaturation for these phases plus those typical of potash-facies mineralization (including kainite, sylvite, carnallite, syngenite, and polyhalite). We propose that the original, detrital clays reacted with magnesium-rich brines to produce a suite of Mg-rich, mixed-layer species and another brine depleted in Mg relative to K. By-products of these reactions were authigenic quartz and K-feldspar. The dissolution of plagioclase, kaolinite, and fine-grained, detrital illite probably contributed components precipitated in the authigenic phases. To summarize, a generalized reaction is suggested: RP STEIN, CL (reprint author), SANDIA NATL LABS,DIV GEOCHEM 6233,ALBUQUERQUE,NM 87185, USA. NR 44 TC 0 Z9 0 U1 1 U2 4 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 SN 0022-4472 J9 J SEDIMENT PETROL PD MAR PY 1991 VL 61 IS 2 BP 174 EP 187 PG 14 WC Geology SC Geology GA FE558 UT WOS:A1991FE55800002 ER PT J AU MARIN, SJ OKEEFFE, M YOUNG, VG VONDREELE, RB AF MARIN, SJ OKEEFFE, M YOUNG, VG VONDREELE, RB TI THE CRYSTAL-STRUCTURE OF SR3Y2GE3O12 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Note C1 ARIZONA STATE UNIV,DEPT CHEM,TEMPE,AZ 85287. UNIV CALIF LOS ALAMOS SCI LAB,LANSCE,LOS ALAMOS,NM 87545. NR 6 TC 2 Z9 2 U1 2 U2 6 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAR PY 1991 VL 91 IS 1 BP 173 EP 175 DI 10.1016/0022-4596(91)90070-X PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA EZ154 UT WOS:A1991EZ15400020 ER PT J AU GRAHAM, AL GOTTLIEB, M DOWELL, F AF GRAHAM, AL GOTTLIEB, M DOWELL, F TI DYNAMICS OF CONCENTRATED SYSTEMS - PREFACE SO JOURNAL OF STATISTICAL PHYSICS LA English DT Editorial Material C1 BEN GURION UNIV NEGEV,IL-84105 BEER SHEVA,ISRAEL. RP GRAHAM, AL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 887 EP 888 DI 10.1007/BF01128166 PG 2 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600001 ER PT J AU DOWELL, F AF DOWELL, F TI OVERVIEW OF PARTIAL ORIENTATIONAL AND POSITIONAL ORDERING IN CONCENTRATED SYSTEMS SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE LIQUID CRYSTALLINE PHASES; STATICS; DYNAMICS; NONPOLYMERIC; POLYMERIC; MICELLES; TRANSITIONS; OVERVIEW ID NEMATIC LIQUID-CRYSTAL; MULTIPLE SMECTIC-A; INTRACHAIN FLEXIBILITY CONSTRAINTS; BLUE PHASES; POLYMERS AB This paper provides an overview of the static behavior of systems with partial orientational and positional ordering of the species. The understanding of the static behavior provides the foundation needed to understand the dynamic properties of such systems, which are described in more detail in other papers in this issue. More specifically, this paper provides an overview of the fact that species of different dimensions exhibit similar types of partial ordering of the species. This paper further provides an overview of liquid crystalline (LC) phases and molecules, including discussions of types of chemical structures (both rigid and semiflexible) in LC molecules (both nonpolymeric and polymeric); thermotropic and lyotropic LCs; nematic and multiple smectic LC phases; reentrant nematic LC phases; cholesteric LC phases and blue phases; smectic crystal phases; columnar phases; micelles and lamellar LC structures; LC phase transitions; LC glasses; viscosities of LC phases; and dynamic textures and patterns in LC phases. RP DOWELL, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 55 TC 0 Z9 0 U1 0 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 927 EP 944 DI 10.1007/BF01128169 PG 18 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600004 ER PT J AU GELBARD, F MONDY, LA OHRT, SE AF GELBARD, F MONDY, LA OHRT, SE TI A NEW METHOD FOR DETERMINING HYDRODYNAMIC EFFECTS ON THE COLLISION OF 2 SPHERES SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE HYDRODYNAMIC EFFECTS ON COLLISIONS; AEROSOL PARTICLE GRAVITATIONAL COAGULATION; ACOUSTICAL DETECTION OF COLLISIONS ID DILUTE POLYDISPERSE SYSTEM; ELASTOHYDRODYNAMIC COLLISION; CLOUD DROPLETS; COAGULATION; EFFICIENCIES; TRANSLATION; PARTICLES; ROTATION; DROPS AB A sphere falling in a fluid may collide with another sphere falling more slowly if, when the spheres are far apart vertically, the horizontal distance between their centers is less than or equal to a critical radius. Accurate prediction of aerosol particle coagulation requires a good understanding of this process. Previously reported optical techniques for measuring hydrodynamic effects on this phenomenon have inherent difficulties detecting grazing collisions and hence in determining the critical radius. In this work, a novel detection technique is demonstrated and it is shown that the critical radius may be determined from the sound generated by the collision of two spheres in a viscous liquid. The technique is shown to provide a more precise and decisive indication of when hard spheres collide. RP GELBARD, F (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 35 TC 4 Z9 4 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 945 EP 960 DI 10.1007/BF01128170 PG 16 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600005 ER PT J AU DOWELL, F AF DOWELL, F TI THEORETICAL PREDICTIONS OF DIFFUSION FROM BROWNIAN-MOTION IN SUPERSTRONG POLYMERS SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE DYNAMIC PROPERTIES; BROWNIAN MOTION; DIFFUSION; SUPERSTRONG POLYMERS; POLYMERS; NONPOLYMERIC MOLECULES; LIQUID CRYSTALLINE PHASES ID MULTIPLE SMECTIC-A; INTRACHAIN FLEXIBILITY CONSTRAINTS; LIQUID-CRYSTALLINE POLYMERS; SEMIFLEXIBLE TAILS; HARD REPULSIONS; ORDERED PHASES; RIGID CORES; MODEL AB This paper presents a summary of unique highly nonlinear static and dynamic theories for chain molecules (actually, for almost any kind of organic molecule), including the first superstrong polymers. These theories have been used to predict and explain (1) the physical self-assembly (self-ordering) of specific kinds of molecules into liquid crystalline (LC) phases (i.e., partially ordered phases) and (2) the diffusion of these molecules in various LC phases and the isotropic (I) liquid phase. RP DOWELL, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 1059 EP 1071 DI 10.1007/BF01128177 PG 13 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600012 ER PT J AU CHEN, SY CHEN, HD DOOLEN, GD GUTMAN, S LEE, MX AF CHEN, SY CHEN, HD DOOLEN, GD GUTMAN, S LEE, MX TI A LATTICE GAS-MODEL FOR THERMOHYDRODYNAMICS SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE LATTICE GAS; THERMOHYDRODYNAMICS; BENARD CONVECTION; GALILEAN INVARIANCE ID CELLULAR AUTOMATON; DYNAMICS; FLUIDS AB The lattice gas model is extended to include a temperature variable in order to study thermohydrodynamics, the combination of fluid dynamics and heat transfer. The compressible Navier-Stokes equations are derived using a Chapman-Enskog expansion. Heat conduction and convection problems are investigated, including Benard convection. It is shown that the usual rescaling procedure can be avoided by controlling the temperature. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RI Chen, Shiyi/A-3234-2010 NR 23 TC 10 Z9 10 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 1121 EP 1151 DI 10.1007/BF01128180 PG 31 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600015 ER PT J AU PHANTHIEN, N ZHENG, R GRAHAM, AL AF PHANTHIEN, N ZHENG, R GRAHAM, AL TI THE FLOW OF A MODEL SUSPENSION FLUID PAST A SPHERE SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE FALLING BALL; SUSPENSION OF FIBERS; BOUNDARY ELEMENT METHOD; ERICKSEN METHOD ID VISCOELASTIC FLUIDS; NEWTONIAN FLUID; PARTICLES; VISCOSITY; DRAG AB The paper is concerned with the flow of a dilute suspension of monosized spheroids past a sphere placed at the centerline of a cylindrical tube. The suspension is modeled by the transversely isotropic fluid model and the numerical solution is obtained by a time-dependent boundary element method. No steady-state solution to the problem was found. However, the amplitude of the long-time oscillations in the drag force on the sphere is only about 1% of its mean value at a solid volume concentration of 0.01 and an aspect ratio of 10 for the spheroids. The initial orientation of the microstructure has a small effect on the drag force: it can give rise to a +/- 1% variation in the drag force at large time. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MECH & ELECTR ENGN,LOS ALAMOS,NM 87544. RP PHANTHIEN, N (reprint author), UNIV SYDNEY,DEPT MECH ENGN,SYDNEY,NSW 2006,AUSTRALIA. RI Phan-Thien, Nhan/I-4705-2012 NR 28 TC 14 Z9 14 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD MAR PY 1991 VL 62 IS 5-6 BP 1173 EP 1195 DI 10.1007/BF01128182 PG 23 WC Physics, Mathematical SC Physics GA FE896 UT WOS:A1991FE89600017 ER PT J AU SCHNEIDER, W RAMACHANDRAN, C SATYASWAROOP, PG SHYAMALA, G AF SCHNEIDER, W RAMACHANDRAN, C SATYASWAROOP, PG SHYAMALA, G TI MURINE PROGESTERONE-RECEPTOR EXISTS PREDOMINANTLY AS THE 83-KILODALTON A-FORM SO JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY LA English DT Article ID MONOCLONAL-ANTIBODIES; NUCLEAR-BINDING; MESSENGER-RNA; OVIDUCT; SEQUENCE; SUBUNIT; REGION; GENE AB Progesterone receptors (PgR) are known to exist in two molecular forms commonly designated as 'A' and 'B' forms, and the relative ratio of these two forms has been shown to vary among species. Although the rodent systems were some of the earliest experimental systems used to examine the regulation of PgR, as yet very little is known concerning the molecular composition of PgR in this species. Accordingly, to define the relative ratio of 'A' and 'B' forms in murine PgR, we have analyzed tissue extracts from normal, ovariectomized, and estradiol treated animals by photoaffinity labeling and immunoblotting techniques using a variety of anti-PgR antibodies. Under all experimental conditions, two forms of PgR with approximate molecular weights of 115 kDa ('B' form) and 83 kDa ('A' form) were found. In all tissues examined, the 83 kDa 'A' form was predominant, and this was independent of the hormonal status of the animal and different buffers used to prepare tissue extracts. In uterus the ratio of 'A' to 'B' was 3:1, in vagina it was 2:1, and in mammary glands it more closely resembled the uterus. This leads us to conclude that murine PgR exists predominantly as the 83-kDa 'A' form which may represent a general characteristic of rodent PgR. In this species there may also be some tissue specificity with regard to the absolute ratio of the two forms of PgR. C1 SIR MORTIMER B DAVIS JEWISH HOSP,LADY DAVIS INST MED RES,MONTREAL H3T 1E2,QUEBEC,CANADA. PENN STATE UNIV,MILTON S HERSHEY MED CTR,DEPT OBSTET & GYNECOL,HERSHEY,PA 17033. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CELL & MOLEC BIOL,BERKELEY,CA 94720. FU NCI NIH HHS [CA46349]; NICHD NIH HHS [HD 22762] NR 27 TC 82 Z9 82 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0960-0760 J9 J STEROID BIOCHEM JI J. Steroid Biochem. Mol. Biol. PD MAR PY 1991 VL 38 IS 3 BP 285 EP 291 DI 10.1016/0960-0760(91)90099-Q PG 7 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism SC Biochemistry & Molecular Biology; Endocrinology & Metabolism GA FG558 UT WOS:A1991FG55800002 PM 2009220 ER PT J AU REID, RA ASPREY, PL AF REID, RA ASPREY, PL TI COMPUTER-PERFORMANCE MANAGEMENT - CONCEPTUAL CONSIDERATIONS FROM AN OPERATIONS-RESEARCH PERSPECTIVE SO JOURNAL OF SYSTEMS AND SOFTWARE LA English DT Article AB A conceptual linkage between computer performance management and the generalized OR model is proposed. This approach seeks to enlarge the managerial perspective so that more effective decisions can be developed and implemented relative to enhancing computer system operating behavior. Basic considerations in computer system performance are mapped to the generalized features of the classical OR model. The result suggests that increased understanding associated with managerial responsibilities in improving performance can be realized. C1 UNIV NEW MEXICO,ANDERSON SCH MANAGEMENT,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,DIV 8525,LIVERMORE,CA 94550. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0164-1212 J9 J SYST SOFTWARE JI J. Syst. Softw. PD MAR PY 1991 VL 14 IS 3 BP 215 EP 219 DI 10.1016/0164-1212(91)90067-G PG 5 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA FH234 UT WOS:A1991FH23400009 ER PT J AU ZWEIG, G AF ZWEIG, G TI FINDING THE IMPEDANCE OF THE ORGAN OF CORTI SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID BASILAR-MEMBRANE MOTION; AUDITORY-NERVE FIBERS; FIBRILLAR FLIGHT-MUSCLE; OUTER HAIR-CELLS; ACOUSTIC EMISSIONS; MOSSBAUER TECHNIQUE; COCHLEAR MODEL; HOMODYNE INTERFEROMETER; TUNING CURVES; VIBRATION AB Measurements of the nonlinear response of the basilar membrane to a pure tone are shown to have a simple form for moderate membrane velocities: V(x,f;V(u))/V(u) almost-equal-to [V approximately (x,f)/V(u)] v(x,f), f less-than-or-equal-to f(c)(x), where the response V is the velocity of the membrane at measurement position x, V(u) is the umbo velocity, f is the frequency of the stimulus, and f(c)(x) is the local characteristic frequency. The frequency dependence of the functions v(x,f) and V approximately (x,f) is determined from the data, and v(x,f) and ln V approximately (x,f) are shown to be analytic functions in the lower half of the complex frequency plane, with Re {v(x,f)} a monotonically increasing function of f at fixed x. The linear limit of basilar membrane motion is characterized by a transfer function T(x,f) = (V approximately /V1)v/(1-v), estimated by extrapolating V(x,f;V(u))/V(u) to a small membrane velocity V1. T(x,f) and ln T(x,f) are shown to be analytic functions in the lower half of the complex frequency plane. The inverse of the amplitude of the transfer function, which has both a deep dip at f almost-equal-to f(c)(x) and a broad shoulder at lower frequencies, bears a striking resemblance to the neural threshold tuning curve. The functional form of T(x,f) is used to deduce the equation governing the motion of a section of the organ of Corti. Each section acts like a negatively damped harmonic oscillator stabilized at time t by a feedback force proportional to the velocity at the previous time t - tau. The time delay tau is proportional to the oscillator period [tau almost-equal-to 1.75/f(c)(x)]. Like a laser, the organ of Corti pumps energy into harmonic traveling waves. Unlike the laser, the direction of energy flow abruptly reverses as the traveling wave approaches the point of maximum membrane velocity [f(c)(x) almost-equal-to f]. All accumulated wave energy is then pumped back into a small section of the organ of Corti where transduction presumably occurs. Outer hair cells are conjectured to be active elements contributing to the negative damping and feedback of the cochlear amplifier. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP ZWEIG, G (reprint author), HEARING RES LAB SIGNIT INC,POB 1020,LOS ALAMOS,NM 87544, USA. NR 85 TC 142 Z9 145 U1 0 U2 4 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 MAR PY 1991 VL 89 IS 3 BP 1229 EP 1254 DI 10.1121/1.400653 PG 26 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA FA701 UT WOS:A1991FA70100025 PM 2030212 ER PT J AU SHERA, CA ZWEIG, G AF SHERA, CA ZWEIG, G TI REFLECTION OF RETROGRADE WAVES WITHIN THE COCHLEA AND AT THE STAPES SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB A number of authors [de Boer and Viergever, Hear. Res. 13, 101-112 (1984); de Boer et al., in Peripheral Auditory Mechanisms (Springer-Verlag, Berlin, 1986); Hear. Res. 23, 1-7 (1986); Viergever, in Auditory Frequency Selectivity (Plenum, New York, 1986), pp. 31-38; Kaernbach et al., J. Acoust. Soc. Am. 81, 408-411 (1987)] have argued that backward-traveling waves, in striking contrast to waves traveling forward towards the helicotrema, suffer appreciable reflection as they move through the basal turns of the cochlea. Such reflection, if present, would have important consequences for understanding the nature and strength of otoacoustic emissions. The apparent asymmetry in reflection of cochlear waves is shown, however, to be an artifact of the boundary condition those authors impose at the stapes: conventional cochlear models are found not to generate reflections of waves traveling in either direction even when the wavelength changes rapidly and the WKB approximation breaks down. Although backward-traveling waves are not reflected by the secular variation of the geometrical and mechanical characteristics of the cochlea, they are reflected when they reach the stapes. The magnitude of that boundary reflection is computed for the cat and shown to be a large, rapidly varying function of frequency. C1 CALTECH,DEPT PHYS,PASADENA,CA 91125. RP SHERA, CA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 0 TC 43 Z9 44 U1 0 U2 0 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 MAR PY 1991 VL 89 IS 3 BP 1290 EP 1305 DI 10.1121/1.400654 PG 16 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA FA701 UT WOS:A1991FA70100029 PM 2030216 ER PT J AU MCKONE, TE KNEZOVICH, JP AF MCKONE, TE KNEZOVICH, JP TI THE TRANSFER OF TRICHLOROETHYENE (TCE) FROM A SHOWER TO INDOOR AIR - EXPERIMENTAL MEASUREMENTS AND THEIR IMPLICATIONS SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID WATER; EXPOSURE; CHEMICALS AB Experiments were performed to measure the transfer of trichloroethylene (TCE), a volatile organic compound (VOC), from tap water in showers to indoor air. In these experiments, the loss of TCE from tap water in the shower is based on the difference between influent and effluent concentrations. We have developed and previously published a three-compartment model, which we use to simulate the 24-h concentration history of VOCs in the shower, bathroom, and remaining household volumes resulting from the use of contaminated tap water. An important input to this model is the transfer efficiency of the VOC from water to air. The experiments reveal that the transfer efficiency of TCE from shower water to air has an arithmetic mean value of 61 percent and an arithmetic standard deviation of 9 percent. Analysis of the results shows that there is no statistically significant difference between the transfer efficiency measured with hot (37-degrees-C) or cold (22-degrees-C) shower water and that there is no statistically significant change in transfer efficiency with time during a 20-min shower. The implications for exposure assessment are considered. RP MCKONE, TE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ENVIRONM SCI,POB 5507,L-453,LIVERMORE,CA 94550, USA. NR 15 TC 5 Z9 5 U1 1 U2 2 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA PO BOX 2861, PITTSBURGH, PA 15230 SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD MAR PY 1991 VL 41 IS 3 BP 282 EP 286 PG 5 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA FC879 UT WOS:A1991FC87900007 PM 2059420 ER PT J AU RAHAMAN, MN DEJONGHE, LC CHU, MY AF RAHAMAN, MN DEJONGHE, LC CHU, MY TI EFFECT OF GREEN DENSITY ON DENSIFICATION AND CREEP DURING SINTERING SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID POWDER COMPACTS; STRESS; STABILITY; KINETICS AB The effect of green density on both the densification rate and the creep rate was measured simultaneously during sintering by loading dilatometry. The experiments were performed on zinc oxide powder compacts with five different green densities covering a range of 0.39 to 0.73 of theoretical. The samples were heated at a constant rate of 4-degrees-C/min up to 1100-degrees-C in air. The densification rate at any temperature increases significantly with decreasing green density. The data for the densification rate and creep rate as a function of density show two quite distinct regimes of behavior; the rates were strongly dependent on density below 0.80, while above this value they were weakly dependent on density. The ratio of the densification rate to the creep rate was almost independent of temperature but increased almost linearly with increasing green density. The representation of the data in terms of models for sintering and creep is discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP RAHAMAN, MN (reprint author), UNIV MISSOURI,DEPT CERAM ENGN,ROLLA,MO 65401, USA. NR 21 TC 50 Z9 52 U1 0 U2 4 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 MAR PY 1991 VL 74 IS 3 BP 514 EP 519 DI 10.1111/j.1151-2916.1991.tb04053.x PG 6 WC Materials Science, Ceramics SC Materials Science GA FC009 UT WOS:A1991FC00900007 ER PT J AU YOUNG, AC OMATETE, OO JANNEY, MA MENCHHOFER, PA AF YOUNG, AC OMATETE, OO JANNEY, MA MENCHHOFER, PA TI GELCASTING OF ALUMINA SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article AB Gelcasting is a novel method for molding ceramic powder based on a synthesis of concepts derived from traditional ceramics and polymer chemistry. Gelcasting of alumina is described in this paper. The process is based on the in situ polymerization of acrylamide monomers as the setting mechanism for forming the green body. It has the following features: slurries with high solids loading and low viscosity (1.8 Pa.s at 62 vol% solids), dried bodies containing less than 4 wt% binder, and the ability to fabricate complex-shaped bodies. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RI Menchhofer, Paul/E-1529-2017 OI Menchhofer, Paul/0000-0001-9475-314X NR 18 TC 547 Z9 630 U1 7 U2 58 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 MAR PY 1991 VL 74 IS 3 BP 612 EP 618 DI 10.1111/j.1151-2916.1991.tb04068.x PG 7 WC Materials Science, Ceramics SC Materials Science GA FC009 UT WOS:A1991FC00900022 ER PT J AU KIM, HE MOORHEAD, AJ AF KIM, HE MOORHEAD, AJ TI STRENGTH OF NICALON SILICON-CARBIDE FIBERS EXPOSED TO HIGH-TEMPERATURE GASEOUS ENVIRONMENTS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID MATRIX COMPOSITES; SIC FIBERS; YARN AB The effects of exposures to high-temperature gaseous atmospheres on the strength of Nicalon SiC fibers were investigated. The exposure conditions were as follows: (1) H2 with various P(H2O) for 10 h at 1000-degrees and 1200-degrees-C, and (2) air for 2 to 100 h at 800-degrees to 1400-degrees-C. Individual fibers were tested in tension following each exposure. The strengths of the fibers were strongly influenced by the exposure atmosphere and temperature, but less affected by time at temperature. When exposed in air, a SiO2 layer was formed on the surface, minimizing the degradation of strength. However, this beneficial effect was negated under conditions in which the SiO2 layer became too thick. The most severe degradation resulted from exposure to a reducing atmosphere, presumably due to the reduction of SiO2 inherent in the fibers. RP KIM, HE (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 17 TC 57 Z9 59 U1 0 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 MAR PY 1991 VL 74 IS 3 BP 666 EP 669 DI 10.1111/j.1151-2916.1991.tb04079.x PG 4 WC Materials Science, Ceramics SC Materials Science GA FC009 UT WOS:A1991FC00900033 ER PT J AU ISAACS, HS AF ISAACS, HS TI THE EFFECT OF HEIGHT ON THE CURRENT DISTRIBUTION MEASURED WITH A VIBRATING ELECTRODE PROBE SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID POTENTIAL DISTRIBUTIONS; CORROSION; SYSTEMS AB The vibrating electrode probe technique for measuring local currents has been tested in order to determine its spacial resolution and to develop methods for analyzing experimental data. Measurements were made with a current source of known size in an insulating plane. Results from this model have been compared with analytical solutions taken from the literature and computer simulations. When the probe was less than 0.2 times the radius of a current source, the major field variations were above the periphery of the source. For heights greater than the diameter of the current source, the field variations closely approximated those of a point current source because of the rapid spreading of the current in the solution. This characteristic was used to simulate the field variations above electrodes by replacing electrodes with an array of elements, each having a single point current source. RP ISAACS, HS (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 21 TC 70 Z9 71 U1 1 U2 5 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 MAR PY 1991 VL 138 IS 3 BP 722 EP 728 DI 10.1149/1.2085665 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA FA236 UT WOS:A1991FA23600012 ER PT J AU ALLENDORF, MD KEE, RJ AF ALLENDORF, MD KEE, RJ TI A MODEL OF SILICON-CARBIDE CHEMICAL VAPOR-DEPOSITION SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID EPITAXIAL-GROWTH; ROTATING-DISK; MATHEMATICAL-MODEL; STICKING COEFFICIENTS; FLUID-MECHANICS; SI(111) SURFACE; PHASE; SI; HYDROGEN; FILMS AB We present a model describing the interacting gas phase and surface chemistry present during the steady-state chemical vapor deposition (CVD) of silicon carbide (SiC). In this work, we treat the case of steady-state deposition of SiC from silane (SiH4) and propane (C3H8) mixtures in hydrogen carrier gas at one atmosphere pressure. Epitaxial deposition is assumed to occur on a pre-existing epitaxial silicon carbide crystal. Pyrolysis of SiH4 and C3H8 is modeled by 83 elementary gas-phase reactions. A set of 36 reactions of gas-phase species with the surface is used to simulate the deposition process. Rates for the gas/surface reactions were obtained from experimental measurements of sticking coefficients in the literature and theoretical estimates. Our results represent the first simualation of a silicon carbide deposition process that includes detailed descriptions of both the gas phase and surface reactions. The chemical reaction mechanism is also combined with a model of a rotating disk reactor (RDR), which is a convenient way to study the interaction of chemical reactions with fluid mechanics. Transport of species from the gas to the surface is accounted for using multicomponent transport properties. Predictions of deposition rates as a function of susceptor temperature, disk rotation rate, and reactant partial pressure are presented. In addition, velocity, temperature, and concentration profiles normal to the heated disk for 41 gas-phase species are determined using reactor conditions typical of epitaxial silicon carbide deposition on silicon substrates. RP ALLENDORF, MD (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 59 TC 176 Z9 179 U1 1 U2 48 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 MAR PY 1991 VL 138 IS 3 BP 841 EP 852 DI 10.1149/1.2085688 PG 12 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA FA236 UT WOS:A1991FA23600035 ER PT J AU MELENDRES, CA ACHO, J KNIGHT, RL AF MELENDRES, CA ACHO, J KNIGHT, RL TI ON THE BREAKDOWN OF PASSIVITY OF IRON BY THIOCYANATE SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Note ID INSITU RAMAN; FILM C1 ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439. RP MELENDRES, CA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 10 TC 19 Z9 19 U1 0 U2 2 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 MAR PY 1991 VL 138 IS 3 BP 877 EP 878 DI 10.1149/1.2085701 PG 2 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA FA236 UT WOS:A1991FA23600049 ER PT J AU PECHARSKY, VK GSCHNEIDNER, KA BODAK, OI PROTSYK, AS AF PECHARSKY, VK GSCHNEIDNER, KA BODAK, OI PROTSYK, AS TI THE CRYSTAL-STRUCTURE, HEAT-CAPACITY (1.5-80 K) AND MAGNETIC-SUSCEPTIBILITY (1.6-300 K) OF LAAGGE AND CEAGGE SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article ID SILICIDES; COMPOUND; CEPTSI AB The crystal structures of the new ternary germanides LaAgGe and CeAgGe were determined from X-ray powder diffractometry data. These compounds crystallize in a new type of superstructure related to the CaIn2-type structure which is characterized by an ordered distribution of the smaller atoms (silver and germanium) in the unit cell and a lower symmetry: space group P6(3)mc instead of P6/mmc. The heat capacity (1.5-80 K), magnetic susceptibility (1.6-300 K) and electric resistivity (4.2-35 K) were measured. CeAgGe orders antiferromagnetically below 4.8 K, and has an electronic specific heat coefficient of 15.7 mJ mol(Ce)-1 K-2 which is typical of normal intermetallic compounds. LaAgGe exhibits an extremely low value of electronic specific heat coefficient (0.18 mJ (g-atom)-1 K-2) which is about four times smaller than that of pure copper. The large residual electrical resistivity, 1250-mu-OMEGA cm, suggests that it is a semimetal or a dirty semiconductor, but the possibility that this large value may be due to microcracks and voids cannot be ruled out. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. LVOV STATE UNIV,DEPT INORGAN CHEM,LVOV 290005,USSR. RP PECHARSKY, VK (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 19 TC 14 Z9 14 U1 2 U2 18 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD MAR PY 1991 VL 168 IS 2 BP 257 EP 267 DI 10.1016/0022-5088(91)90307-P PG 11 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FF609 UT WOS:A1991FF60900012 ER PT J AU ZHANG, Y FRANZEN, HF AF ZHANG, Y FRANZEN, HF TI A SINGLE-CRYSTAL STRUCTURE DETERMINATION OF TM15S22 - A NEW THULIUM SULFIDE SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article AB The title compound has been prepared by high temperature techniques. A single crystal X-ray study has identified the structure type and composition of Tm15S22 with space group C2/m, Z = 2, a = 38.395(4) angstrom, b = 3.8421(5) angstrom, c = 11.141(2) angstrom, beta = 91.02(1)-degrees; R/R(w) = (2.56/2.95)% for 1072 independent reflections. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP ZHANG, Y (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 8 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD MAR PY 1991 VL 168 IS 2 BP 377 EP 382 DI 10.1016/0022-5088(91)90319-Y PG 6 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FF609 UT WOS:A1991FF60900024 ER PT J AU CAMERON, R CANTATORE, G MELISSINOS, AC ROGERS, J SEMERTZIDIS, Y HALAMA, H PRODELL, A NEZRICK, FA RIZZO, C ZAVATTINI, E AF CAMERON, R CANTATORE, G MELISSINOS, AC ROGERS, J SEMERTZIDIS, Y HALAMA, H PRODELL, A NEZRICK, FA RIZZO, C ZAVATTINI, E TI MEASUREMENT OF THE MAGNETIC BIREFRINGENCE OF NEON GAS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID DETECT; FIELD AB We constructed a sensitive ellipsometer to study extremely small ellipticities that are acquired by laser light when it traverses a multipass optical cavity in a 9-m-long superconducting magnet. This setup was used to measure the Cotton-Mouton constant (C(CM)) of neon at 514.5 nm. We find for 760 Torr (1 atm) and 25-degrees-C that C(CM)(Ne) = (5.5 +/- 0.3) x 10(-20) G-2 cm-1. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,I-34127 TRIESTE,ITALY. UNIV TRIESTE,DIPARTMENTO FIS,I-34127 TRIESTE,ITALY. RP CAMERON, R (reprint author), UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627, USA. RI Semertzidis, Yannis K./N-1002-2013 NR 16 TC 26 Z9 26 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 1991 VL 8 IS 3 BP 520 EP 524 DI 10.1364/JOSAB.8.000520 PG 5 WC Optics SC Optics GA FA751 UT WOS:A1991FA75100004 ER PT J AU FELDMAN, U EKBERG, JO SEELY, JF BROWN, CM KANIA, DR MACGOWAN, BJ KEANE, CJ BEHRING, WE AF FELDMAN, U EKBERG, JO SEELY, JF BROWN, CM KANIA, DR MACGOWAN, BJ KEANE, CJ BEHRING, WE TI TRANSITIONS OF THE TYPE 2S-2P IN HIGHLY CHARGED FLUORINE-LIKE AND OXYGEN-LIKE MO, CD, IN, AND SN SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID = 2-2 TRANSITIONS; ENERGY-LEVELS; 2S22P5-2S2P6 TRANSITIONS; IONS; SPECTRA; WAVELENGTHS; PLASMAS; TOKAMAK; XXIV; XXV AB Transitions of the type 2s-2p in the F I and O I isoelectronic sequences have been identified in the extreme-ultraviolet spectra from plasmas that were produced by one beam of the Nova laser. In the F I sequence, two transitions were observed for the ions Mo33+, Cd39+, In40+, and Sn41+. In the O I sequence, 13 transitions were observed for Mo34+, 7 transitions for Cd40+, 8 transitions for In41+, and 7 transitions for Sn42+. The observed wavelengths were compared with calculated wavelengths, and predicted wavelengths are presented for the F I sequence up to atomic number Z = 64 and for the O I sequence to Z = 54. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,SOLAR PHYS BRANCH,GREENBELT,MD 20771. RP FELDMAN, U (reprint author), USN,RES LAB,EO HULBURT CTR SPACE RES,WASHINGTON,DC 20375, USA. NR 19 TC 12 Z9 12 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 1991 VL 8 IS 3 BP 531 EP 537 DI 10.1364/JOSAB.8.000531 PG 7 WC Optics SC Optics GA FA751 UT WOS:A1991FA75100006 ER PT J AU REISER, C RAYMOND, TD MICHIE, RB AF REISER, C RAYMOND, TD MICHIE, RB TI EFFICIENT 2ND STOKES RAMAN CONVERSION IN HYDROGEN SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID BEAM CLEANUP; FREQUENCY-CONVERSION; SCATTERING; GENERATION; AMPLIFICATION; FLUCTUATIONS; AMPLIFIERS AB We report cascade Raman generation of 313-nm radiation by second Stokes Raman shifting 248-nm pulses in H-2. A single seed generator was used to produce the first and second Stokes seed beams. Both collinear- and crossed-beam amplifier configurations were investigated. A peak conversion efficiency of 43% was obtained in a 2-m amplifier cell containing 16 atm of hydrogen. Under optimized conditions, the phase front of the second Stokes beam exhibited only a fraction of a wave of aberration. We find that a trade-off between high beam quality and high conversion efficiency exists in a system that relies on a single seed generator. C1 MISSION RES CORP,ALBUQUERQUE,NM 87106. RP REISER, C (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 27 TC 6 Z9 6 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 1991 VL 8 IS 3 BP 562 EP 569 DI 10.1364/JOSAB.8.000562 PG 8 WC Optics SC Optics GA FA751 UT WOS:A1991FA75100010 ER PT J AU TURCHI, PEA FINEL, A AF TURCHI, PEA FINEL, A TI NEW POSSIBLE ORDERED STATES BASED ON THE A15 CRYSTALLINE-STRUCTURE SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article ID ALLOYS AB New ordered states based on the A15 crystalline structure at the compositions A5B3 and A7B are found from a ground state analysis of the Ising model on this lattice with first, second and weak third and seventh neighbor pair interactions. Stability properties as a function of temperature and concentration were investigated by means of a variational method. A typical prototype A15-based order disorder phase diagram is presented and discussed in relation with the experimental situation. C1 OFF NATL ETUD & RECH AEROSP,F-92322 CHATILLON,FRANCE. RP TURCHI, PEA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV CONDENSED MATTER L-268,LIVERMORE,CA 94550, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU PHYSICAL SOCIETY JAPAN KIKAI-SHINKO BUILDING PI TOKYO PA 3-5-8 SHIBA-KOEN MINATO-KU, TOKYO 105, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD MAR PY 1991 VL 60 IS 3 BP 942 EP 946 DI 10.1143/JPSJ.60.942 PG 5 WC Physics, Multidisciplinary SC Physics GA FM073 UT WOS:A1991FM07300036 ER PT J AU SOUERS, PC FEARON, EM SATER, JD MAPOLES, ER GAINES, JR FEDDERS, PA AF SOUERS, PC FEARON, EM SATER, JD MAPOLES, ER GAINES, JR FEDDERS, PA TI NUCLEAR-RELAXATION OF DEUTERIUM TRITIUM ABSORBED ONTO SILICA AEROGEL SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article ID A-SI-H; NMR RELAXATION; HYDROGEN; GRAPHITE AB The longitudinal nuclear relaxation times of tritons in equilibrium deuterium-tritium (eD-T, actually D2-DT-T2) adsorbed onto amorphous silica aerogel has been measured from 4.2 to 23 K from 0.5 to 6.2 monolayers of coverage. Below 7 K, the relaxation time dramatically increases with decreasing temperature, especially for low coverages. A value of 16 s for 0.5 monolayer at 4.2 K may be compared with the usual electric quadrupole-quadrupole (EQQ) determined relaxation time of 0.1 s. It is shown that absorption of 10% of the tritium beta particle energy occurs in aerogel fully loaded with D-T. This decreases the concentration of J = 1 T2 and increases the nuclear relaxation time. Similar energy absorption calculations in the thin layers shows that long relaxation times are expected, and that the measured values must be caused by spin-lattice relaxation with the aerogel surface. Both (temperature)-7 and exponential mechanisms are considered with no final decision being possible. Electric field gradients from the aerogel walls are considered the likely relaxation mechanism. These finding suggest that a long triton relaxation time may be achievable in ultrapure DT in the silica aerogel. Such a result would be of considerable importance to nuclear polarized inertial confinement fusion targets. C1 UNIV HAWAII, DEPT PHYS, HONOLULU, HI 96822 USA. WASHINGTON UNIV, DEPT PHYS, ST LOUIS, MO 63130 USA. RP UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DEPT CHEM & MAT SCI, LIVERMORE, CA 94550 USA. NR 27 TC 1 Z9 1 U1 3 U2 3 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD MAR-APR PY 1991 VL 9 IS 2 BP 232 EP 237 DI 10.1116/1.577527 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA FC868 UT WOS:A1991FC86800011 ER PT J AU FOWLER, GL AF FOWLER, GL TI COOLING RESERVOIR FOR HORIZONTAL MANIPULATOR SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Note AB A new reservoir design makes it possible to retain liquid nitrogen in a horizontal manipulator without sacrificing any movements of an x-y-z, rotational manipulator. The entanglement of leads and nitrogen tubes encountered in conventional cooling designs is eliminated. A fixture was also developed to insure proper axial alignment when installing the reservoir. RP FOWLER, GL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAR-APR PY 1991 VL 9 IS 2 BP 360 EP 361 DI 10.1116/1.577516 PG 2 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA FC868 UT WOS:A1991FC86800035 ER PT J AU CECCHI, JL STEVENS, JE JARECKI, RL HUANG, YC AF CECCHI, JL STEVENS, JE JARECKI, RL HUANG, YC TI OPERATIONAL CHARACTERISTICS OF SF6 ETCHING IN AN ELECTRON-CYCLOTRON RESONANCE PLASMA REACTOR SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT WORKSHOP ON HIGH-DENSITY PLASMA TECHNIQUES AND PROCESSES FOR INTEGRATED CIRCUIT FABRICATION CY SEP 11-12, 1990 CL BURLINGAME, CA SP AMER VACUUM SOC ID ION-SOURCE; SILICON AB The initial operation of an electron cyclotron resonance (ECR) plasma etch tool, utilized in a downstream configuration for SF6 etching of polysilicon is described. Practical operational characteristics that are generic to high-density, wave-supported plasma sources operated in downstream configurations were explored. A method for improved coupling of the microwave power to the ECR source is described. This method eliminates the need for external tuning. The effect of wall impurities on the plasma and etching characteristics is also considered. A scheme for conditioning the walls to alleviate the effects of impurities is presented. Finally, the complicated relationship between the ECR source plasma and the downstream wafer is considered, by examining the scaling of the plasma electron density in the two regions with microwave power and gas pressure. The phenomena discussed here apply to other etching chemistries and can have a significant impact on process integrity and ease of operation. RP CECCHI, JL (reprint author), PRINCETON UNIV,DEPT CHEM ENGN,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08544, USA. NR 18 TC 36 Z9 36 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 318 EP 324 DI 10.1116/1.585612 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL003 UT WOS:A1991FL00300020 ER PT J AU FERRELL, TL GOUNDONNET, JP REDDICK, RC SHARP, SL WARMACK, RJ AF FERRELL, TL GOUNDONNET, JP REDDICK, RC SHARP, SL WARMACK, RJ TI THE PHOTON SCANNING TUNNELING MICROSCOPE SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB AB The tunneling of photons from an evanescent wave to a sharpened optical fiber probe tip provides the basis for an analogous instrument to the electron scanning tunneling microscope. The transmission and reflection coefficients for s-polarized photons are exactly the same as those for electrons. Imaging at subwavelength resolution is made possible by the exponential character of the tunneling. We have constructed several photon scanning tunneling microscopes (PSTMs) and successfully imaged the topography of a number of samples placed on microscope slides. Each slide is coupled to a prism with an index matching gel and light is internally reflected within the sample. The reflection is frustrated as tunneling sets in when the probe tip is brought close to the surface. The electronics and software used are similar to those used in our electron STMs. Lateral resolution of lambda /12 has been obtained and high-resolution spectroscopy has also been accomplished simultaneously. Images of several types of samples, including biological samples will be presented. RP FERRELL, TL (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,POB 2008,OAK RIDGE,TN 37831, USA. NR 4 TC 20 Z9 20 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 525 EP 530 DI 10.1116/1.585561 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400025 ER PT J AU TENCH, RJ BALOOCH, M BERNARDEZ, L ALLEN, MJ SIEKHAUS, WJ OLANDER, DR WANG, W AF TENCH, RJ BALOOCH, M BERNARDEZ, L ALLEN, MJ SIEKHAUS, WJ OLANDER, DR WANG, W TI CLUSTERS FORMED IN LASER-INDUCED ABLATION OF SI, SIC, PT, UO2 AND EVAPORATION OF UO2 OBSERVED BY LASER IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY AND SCANNING TUNNELING MICROSCOPY SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID SUPERCONDUCTING FILMS; CU; AU; DEPOSITION; AG AB Cluster formation is traditionally observed by mass spectrometry, which has the disadvantage that the detection sensitivity often decreases with increasing mass. Alternatively, one may collect the clusters onto an atomically flat substrate and identify them by scanning tunneling microscopy (STM). Both techniques were used here. For the first technique, a Nd:YAG laser (frequency quadrupled to 266 nm, 5 ns pulse width) focused onto spots of 4-100-mu-m diameter was used to ablate refractory materials, and a reflectron time-of-flight tube served to mass-analyze the plumes. The observed mass spectra for Si, Pt, SiC, and UO2 varied in the distribution of ablation products among atoms, molecules, and clusters, depending on laser power density and target material. For the second technique, cleaved surfaces of highly oriented pyrolytic graphite were positioned either 10 cm away from materials ablated at 10(-5) Torr by 1-3 excimer laser (308 nm) pulses of 20 ns duration, or 1 m away from materials vaporized at 10(-8) Torr by 10 Nd:Glass laser pulses of 1 ms duration. The deposited material was then analyzed by STM in air. Clusters up to 30 angstrom in diameter were observed for all materials, making the use of STM at room temperature for mass analysis questionable. C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. RP TENCH, RJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 10 TC 18 Z9 18 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 820 EP 824 DI 10.1116/1.585519 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400093 ER PT J AU WANG, HC OGLETREE, DF SALMERON, M AF WANG, HC OGLETREE, DF SALMERON, M TI SCANNING TUNNELING MICROSCOPY STUDY OF TIOX ON RH(111) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID SURFACE ELECTRONIC-STRUCTURE; METAL SUPPORT INTERACTIONS; MODEL CATALYSTS; OVERLAYERS; TITANIA; RH AB Scanning tunneling microscopy has been used to study submonolayer coverages of titanium oxide on rhodium. After reduction with CO, titania is shown to form one atomic layer thick island approximately 20 angstrom in size on the Rh(111) surface at submonolayer coverages. High resolution filled state images show enhanced contrast at the island perimeter. The "ring shaped" appearance of the islands is related to the electronic structure of the titania overlayer. RP WANG, HC (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR ADV MAT,BERKELEY,CA 94720, USA. RI Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 14 TC 14 Z9 14 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 853 EP 856 DI 10.1116/1.585526 PN 2 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400100 ER PT J AU OGLETREE, DF HWANG, RQ ZEGLINSKI, DM VAZQUEZDEPARGA, AL SOMORJAI, GA SALMERON, M AF OGLETREE, DF HWANG, RQ ZEGLINSKI, DM VAZQUEZDEPARGA, AL SOMORJAI, GA SALMERON, M TI SCANNING TUNNELING MICROSCOPY STUDIES OF SULFUR OVERLAYERS ON THE RE(0001) SURFACE SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID COADSORPTION AB The structure of sulfur adsorbed on the basal plane of rhenium has been studied in ultrahigh vaccum with Auger, low-energy electron diffraction, and scanning tunneling microscopy. At low coverages ( < 0.25 monolayers) single sulfur adatoms form open structures with p(2X2) and c(square-root 3X5) rectangular lattices. In these structures both the sulfur adatoms and some of the rhenium substrate atoms are imaged simultaneously, identifying the sulfur adsorption site as a threefold hollow site. At coverages above 0.25 ML sulfur adatoms aggregate into trimers, first disordered and then ordered into a (3 square-root 3 x 3 square-root 3) R 30-degrees lattice at a coverage of 0.45 ML. Two types of trimers form that are centered around different substrate sites. Between 0.45 and 0.5 ML diamond-shaped sulfur tetramers appear until an ordered (13(31)) structure forms. With further exposure to H-2S a final structure is formed, consisting of hexagonal sulfur rings in a (2 square-root 3 x 2 square-root 3) R 30-degrees lattice. All of the sulfur adatoms in the three high coverage structures occupy the same type of threefold hollow sites as in the low coverage structures. C1 UNIV AUTONOMA MADRID, DEPT MAT CONDENSADA, MADRID 34, SPAIN. RP UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DIV MAT SCI, CTR ADV MAT, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. RI Vazquez de Parga, Amadeo/L-2418-2013; Ogletree, D Frank/D-9833-2016 OI Vazquez de Parga, Amadeo/0000-0003-0551-1603; Ogletree, D Frank/0000-0002-8159-0182 NR 13 TC 46 Z9 46 U1 0 U2 0 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 886 EP 890 DI 10.1116/1.585489 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400107 ER PT J AU ZHANG, Z LIEBER, CM GINLEY, DS BAUGHMAN, RJ MOROSIN, B AF ZHANG, Z LIEBER, CM GINLEY, DS BAUGHMAN, RJ MOROSIN, B TI SCANNING TUNNELING MICROSCOPY AND SPECTROSCOPY STUDIES OF THE SURFACE-STRUCTURE AND ELECTRONIC-PROPERTIES OF SINGLE-CRYSTAL TL-BA-CA-CU-O SUPERCONDUCTORS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID BULK SUPERCONDUCTIVITY; TL2BA2CA2CU3O10; TL2BA2CACU2O8; SYSTEM; 125-K AB Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) have been used to characterize the surface structure and electronic properties of Tl2Ba2CaCu2O8 and Tl2Ba2Ca2Cu3O10 single crystals. Atomic resolution STM images show that 90%-95% of the surface has a near-trigonal structure with a = b = 0.24 nm and an a-b angle of 65-degrees. The remaining 5%-10% of the surface consists of a new orthorhombic structure with a = b = 0.40 nm. Spatially resolved STS measurements further demonstrate that regions with the 0.24 nm period structure are metallic, while areas with the 0.40 nm period structure are semiconducting. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP ZHANG, Z (reprint author), COLUMBIA UNIV,DEPT CHEM,NEW YORK,NY 10027, USA. NR 14 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1009 EP 1012 DI 10.1116/1.585799 PN 2 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400131 ER PT J AU BALOOCH, M SCHILDBACH, M TENCH, R ALLEN, M SIEKHAUS, WJ AF BALOOCH, M SCHILDBACH, M TENCH, R ALLEN, M SIEKHAUS, WJ TI SURFACE SITE SPECIFICITY ON THE BASAL-PLANE OF GRAPHITE - 1.06 MU-M LASER DAMAGE THRESHOLD AND REACTIVITY WITH OXYGEN BETWEEN 350 AND 2300-K SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID SPECTROSCOPY; OXIDATION AB Scanning tunneling microscopy (STM) has been used to document changes in the nanometer-scale morphology of the basal plane of highly oriented pyrolytic graphite after in situ exposure to 7 ns, 1064 nm Nd:YAG, and to ms Nd:Glass laser pulses producing surface temperatures up to 2300 K, and after ex situ exposure to temperatures as low as 350 K in air. Laser damage produced by the ns pulses was visible by STM at fluences far below those that produce melting and effects visible by other imaging techniques. Damage appears first on step edges and consists of exfoliation of graphite layers and recession of steps through removal of mono- or multilayer patches, ms and long-term heating leads to reaction with oxygen, which proceeds by etching of both crystalline boundaries and step edges. In addition a high concentration of flat-bottom shallow pits (two monolayers deep) and a smaller number of conical pits (greater than 30 angstrom deep) can clearly be identified. The results give for the reaction at the grain boundaries an activation energy of 36 kcal/mole while for steps and shallow pits it is 53 kcal/mole, within the energy range found in global, not site-specific reaction studies. Site-specific reaction probabilities as low as 10(-11) are measured at 350 K. C1 UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV E & B,LIVERMORE,CA 94550. RP BALOOCH, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV CONDENSED MATTER & ANALYT SCI,LIVERMORE,CA 94550, USA. NR 14 TC 11 Z9 11 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1088 EP 1091 DI 10.1116/1.585266 PN 2 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400149 ER PT J AU HAWLEY, ME BENICEWICZ, BC AF HAWLEY, ME BENICEWICZ, BC TI STRUCTURAL STUDY OF A WHOLLY AROMATIC POLYAMIDE WITH A RIGID PENDENT GROUP BY SCANNING TUNNELING MICROSCOPY SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB AB The scanning tunneling microscope was used to study nonconducting wholly aromatic polyamide chains deposited onto highly oriented pyrolytic graphite (HOPG) substrates. Images, taken in air, were analyzed to address questions concerning the attachment sites of rigid pendent groups to the polymeric molecular backbone as well as to answer general, larger morphological questions relating to such issues as possible helical coiling of chains, monomeric or dimeric, and multichain aggregation. Films were prepared from solutions of the polyamide dissolved in dimethylacetamide and differing in salt content to change the degree of association between chains and, therefore, the tendency of chains to form large bundles. Evidence was found for coiling of multimolecular chains and a tendency to form large ordered multimacromolecular assemblies. RP HAWLEY, ME (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 7 TC 6 Z9 6 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1141 EP 1147 DI 10.1116/1.585234 PN 2 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400161 ER PT J AU WILSON, TE MURRAY, MN OGLETREE, DF BEDNARSKI, MD CANTOR, CR SALMERON, MB AF WILSON, TE MURRAY, MN OGLETREE, DF BEDNARSKI, MD CANTOR, CR SALMERON, MB TI SCANNING TUNNELING MICROSCOPY AT HIGH GAP RESISTANCES AND ON CHEMICALLY MODIFIED SILICON SURFACES SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID MONOLAYERS AB Scanning tunneling microscopy (STM) studies of organic or biological molecules are difficult to reproduce because strong tip-surface interactions can displace weakly bound material at the surface. We have studied conducting organic monolayers and nucleic acids with out STM instrument at high gap resistance values (100 G-OMEGA to 1 T-OMEGA). We have succeeded in imaging chemically modified silicon surfaces. It is our desire to use these chemically modified surfaces in conjunction with higher gap values in the future to reliably image DNA. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR HUMAN GENOME RES,BERKELEY,CA 94720. RP WILSON, TE (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. RI Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 14 TC 26 Z9 26 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1171 EP 1176 DI 10.1116/1.585240 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400167 ER PT J AU ALLEN, MJ TENCH, RJ MAZRIMAS, JA BALOOCH, M SIEKHAUS, WJ BALHORN, R AF ALLEN, MJ TENCH, RJ MAZRIMAS, JA BALOOCH, M SIEKHAUS, WJ BALHORN, R TI A PULSE-DEPOSITION METHOD FOR SCANNING TUNNELING MICROSCOPY OF DEOXYRIBONUCLEIC-ACID ON GRAPHITE SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID RECA-DNA COMPLEXES; AQUEOUS ENVIRONMENT; DOUBLE HELIX; IMAGES AB Images of three different synthetic DNAs have been obtained by scanning tunneling microscopy (STM) following their deposition on graphite using a voltaic pulse. DNA applied to the STM tip is desorbed during a 4 V/10-mu-s pulse and deposited intact onto the surface of highly oriented pyrolytic graphite. Images of 22, 47, and 100 base-pair molecules show that deposition occurs in close proximity to the tunneling tip and that the molecules appear to deposit singly or in highly oriented groups. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT APPL SCI,LIVERMORE,CA 94550. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550. RP ALLEN, MJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550, USA. NR 25 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1272 EP 1275 DI 10.1116/1.585219 PN 2 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400189 ER PT J AU SALMERON, M OGLETREE, DF OCAL, C WANG, HC NEUBAUER, G KOLBE, W MEYERS, G AF SALMERON, M OGLETREE, DF OCAL, C WANG, HC NEUBAUER, G KOLBE, W MEYERS, G TI TIP-SURFACE FORCES DURING IMAGING BY SCANNING TUNNELING MICROSCOPY SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL CONF ON SCANNING TUNNELING MICROSCOPY/SPECTROSCOPY ( STM 90 ) / 1ST INTERNATIONAL CONF ON NANOMETER SCALE SCIENCE AND TECHNOLOGY ( NANO 1 ) CY JUL 23-27, 1990 CL BALTIMORE, MD SP AMER VACUUM SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, NATL SCI FDN, JOHN HOPKINS UNIV, APPL PHYS LAB ID GRAPHITE SURFACE; SULFUR AB The effect of compressive and shear forces between tip and surface during the operation of the scanning tunneling microscope (STM) is illustrated with examples obtained both in air and vacuum environments. We show that at typical gap resistances used in STM (less-than-or-equal-to 20 G-OMEGA) these forces can have significant effects. Compressive or repulsive forces give rise to anomalous topographic corrugations (elastic deformations) as well as to permanent damage (inelastic or plastic deformation). These forces also cause the anomalously low values obtained in measurements of the tunneling barrier height. The effects of shear forces when imaging weakly bound material will also be demonstrated. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. DOW CHEM CO USA,MIDLAND,MI 48674. RP SALMERON, M (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV ENGN,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. RI Ogletree, D Frank/D-9833-2016; Ocal, Carmen/G-8590-2013 OI Ogletree, D Frank/0000-0002-8159-0182; Ocal, Carmen/0000-0001-8790-8844 NR 18 TC 61 Z9 61 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 1991 VL 9 IS 2 BP 1347 EP 1352 DI 10.1116/1.585194 PN 2 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA FL004 UT WOS:A1991FL00400206 ER PT J AU LAUGHLIN, AW GOFF, SJ AF LAUGHLIN, AW GOFF, SJ TI RECENT GEOTHERMAL INVESTIGATIONS IN HONDURAS - AN OVERVIEW SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Review ID AMERICA AB Since 1985, the Los Alamos National Laboratory and the U.S. Geological Survey have worked with the Empresa Nacional de Energia Electrica of Honduras to perform a geothermal assessment of six areas in Honduras. A combination of reconnaissance and detailed techniques was used to eliminate from consideration the sites of lower potential. Detailed geophysical investigations were performed at two high-potential sites and three geothermal gradient coreholes were drilled at the highest potential site, Platanares. High-temperature fluids were encountered in two of these coreholes, while one hole was non-flowing. Evaluation of all the data collected suggests that there are two levels to the geothermal reservoir at Platanares. A shallow (< 700 m) level contains 160 - 165-degrees-C fluids while a deeper (> 1.2 km) reservoir at a temperature of 225-degrees is indicated by fluid geothermometers. RP LAUGHLIN, AW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & SPACE SCI,GEOTHERMAL RESOURCES DEV PROJECT,LOS ALAMOS,NM 87545, USA. NR 23 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 1 EP 9 PG 9 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000002 ER PT J AU ANDER, ME AIKEN, CLV DELAFUENTE, MF AF ANDER, ME AIKEN, CLV DELAFUENTE, MF TI REGIONAL GRAVITY INVESTIGATION OF HONDURAS, CENTRAL-AMERICA SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article AB A regional gravity study of Honduras was performed as part of a major study of the geothermal resource potential of Honduras. This study was conducted by Los Alamos National Laboratory, in cooperation with the Honduras government. Regional offshore free-air and onshore Bouguer gravity maps, and residual/isostatic gravity maps of Honduras and surrounding regions were produced. From these data several regional crustal and upper mantle models were produced. These models pass through two local geothermal sites, Platanares and San Ignacio. The regional geologic and tectonic implications of the models and their relevance to the geothermal potential of Honduras and to six well known geothermal sites in particular are examined. No obvious regional structures observed in the gravity data can explain the thermal enhancement in general or the specific geothermal sites. More local tectonic or structural conditions must control the distribution of the thermally enhanced areas. C1 UNIV TEXAS,CTR LITHOSPHER STUDIES,RICHARDSON,TX 75080. NATL AUTONOMOUS UNIV MEXICO,INST GEOL,MEXICO CITY 04510,DF,MEXICO. RP ANDER, ME (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GEOPHYS GRP,LOS ALAMOS,NM 87545, USA. NR 32 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 11 EP 27 DI 10.1016/0377-0273(91)90019-V PG 17 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000003 ER PT J AU HEIKEN, G RAMOS, N DUFFIELD, W MUSGRAVE, J WOHLETZ, K PRIEST, S ALDRICH, J FLORES, W RITCHIE, A GOFF, F EPPLER, D ESCOBAR, C AF HEIKEN, G RAMOS, N DUFFIELD, W MUSGRAVE, J WOHLETZ, K PRIEST, S ALDRICH, J FLORES, W RITCHIE, A GOFF, F EPPLER, D ESCOBAR, C TI GEOLOGY OF THE PLATANARES GEOTHERMAL AREA, DEPARTAMENTO-DE-COPAN, HONDURAS SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article AB The Platanares geothermal area, Departamento de Copan, Honduras, is located within a graben that is complexly faulted. The graben is bounded on the north by a highland composed of Paleozoic (?) metamorphic rocks in contact with Cretaceous - Tertiary redbeds of unknown thickness. These are unconformably overlain by Tertiary andesitic lavas, rhyolitic ignimbrites, and associated sedimentary rocks. The volcanic rocks are mostly older than 14 Ma, and thus are too old to represent the surface expression of an active crustal magma body. Thermal fluids that discharge in the area are heated during deep circulation of meteoric water along faults in a region of somewhat elevated heat flow. Geothermometry based upon the chemical composition of thermal fluids from hot springs and from geothermal gradient coreholes suggests that the reservoir equilibrated at temperatures as high as 225 to 240-degrees-C, within the Cretaceous redbed sequence. Three continuously cored geothermal gradient holes have been drilled; fluids of about 165-degrees-C have been produced from two drilled along a NW-trending fault zone, from depths of 250 to 680 m. A conductive thermal gradient of 139-degrees-C/km, at a depth of 400 m, was determined from the third well, drilled 0.6 km west of that fault zone. These data indicate that the Platanares geothermal area holds considerable promise for electrical generation by moderate-to high-temperature geothermal fluids. C1 EMPRESA NACL ENERGIA ELECT,TEGUCIGALPA,HONDURAS. COLL CHARLESTON,CHARLESTON,SC 29424. US GEOL SURVEY,FLAGSTAFF,AZ 86001. RP HEIKEN, G (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS 964,LOS ALAMOS,NM 87544, USA. NR 38 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 41 EP 58 DI 10.1016/0377-0273(91)90021-Q PG 18 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000005 ER PT J AU ALDRICH, MJ ADAMS, AI ESCOBAR, C AF ALDRICH, MJ ADAMS, AI ESCOBAR, C TI STRUCTURAL GEOLOGY AND STRESS HISTORY OF THE PLATANARES GEOTHERMAL SITE, HONDURAS - IMPLICATIONS ON THE TECTONICS OF THE NORTHWESTERN CARIBBEAN PLATE BOUNDARY SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article ID NORTHERN CENTRAL-AMERICA; FAULT; RANGE; GUATEMALA; ROTATION; BLOCKS; BASIN AB The structural geology of the Platanares geothermal site in western Honduras, located about 25 km south of the northern boundary of the Caribbean plate, is the result of post Early Miocene extensional deformation. Normal faults, many with listric geometries, are numerous throughout the area. Strike-slip faulting has mostly occurred on reactived normal faults. Analysis of the fault slip data shows an older minimum principal stress, sigma-3, oriented approximately N-S and a contemporary sigma-3 tensional and oriented ENE - WSW. The analysis suggests that sigma-3 has rotated clockwise since the Early Miocene although some of the change in orientation of sigma-3 might reflect counterclockwise rotation of the crust about a vertical axis. The sigma-1 and sigma-2 stress axes apparently switched recently, with the sigma-3 axis remaining unchanged. These results are consistent with a tectonic model in which the east-drifting Caribbean plate is pinned against North America by the subducting Cocos plate (Malfait and Dinkleman, 1972) and the northern and southern margins of the Caribbean plate are broad, mobile zones that are undergoing counterclockwise and clockwise rotations respectively (Gose, 1985). The majority of the hot springs at Platanares lie along Quebrada del Agua Caliente. Fractures control the movement of the geothermal waters. Hot springs occur along joints and faults and, in places, hot water flows laterally along bedding planes. If the fractures also control the movement of water at depth then the source reservoir of the geothermal waters may be located northeast of the principal hot spring areas along the quebrada since the majority of the faults dip in that direction. However, if the fault that seems to have controlled the development of Quebrada del Agua Caliente is vertical as inferred then the main reservoir may lie directly beneath this drainage. C1 EMPRESA NACL ENERGIA ELECT,TEGUCIGALPA,HONDURAS. RP ALDRICH, MJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MAIL STOP D462,LOS ALAMOS,NM 87545, USA. NR 27 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 59 EP 69 DI 10.1016/0377-0273(91)90022-R PG 11 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000006 ER PT J AU AIKEN, CL ANDER, ME DELAFUENTE, MF AF AIKEN, CL ANDER, ME DELAFUENTE, MF TI GEOPHYSICAL INVESTIGATIONS OF THE PLATANARES GEOTHERMAL SITE, HONDURAS, CENTRAL-AMERICA SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article AB Geophysical studies were carried out in Platanares in Western Honduras, as part of an investigation of the geothermal resource potential of Honduras by Los Alamos National Laboratory in cooperation with the Honduran government and the U.S. Geological Survey. Geological and geochemical studies later followed by exploratory bore-holes indicate this area of rugged topography has the best geothermal potential in Honduras. In order to better understand the geology of the area, gravity, audiomagnetotelluric and telluric surveys were carried out. The site is in a graben of Tertiary volcanics and Cretaceous red beds, with numerous hot springs along faults in the center of the graben. Gravity mapped the thickness of low-density tuffs and the position of associated normal faults. It also indicated the presence of persuasive, shallow, highly silicified, high-density tuffs and gravels. The electrical surveys mapped shallow, high-resistivity silicified zones and faults as low-resistivity zones. The red beds below the tuffs are considered to contain the geothermal reservoir, but their maximum thickness could not be determined by these surveys due to the lack of density contrast and the high surface electrical conductivities. Three geologic cross-sections constructed by others have been re-evaluated using gravity modeling and analysis of electrical anomalies, showing general agreement but in detail significant differences. C1 UNIV CALIF LOS ALAMOS SCI LAB,GEOPHYS GRP,LOS ALAMOS,NM 87545. NATL AUTONOMOUS UNIV MEXICO,INST GEOL,MEXICO CITY 04510,DF,MEXICO. RP AIKEN, CL (reprint author), UNIV TEXAS,CTR LITHOSPHER STUDIES,RICHARDSON,TX 75083, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 71 EP 90 DI 10.1016/0377-0273(91)90023-S PG 20 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000007 ER PT J AU GOFF, F GOFF, SJ KELKAR, S SHEVENELL, L TRUESDELL, AH MUSGRAVE, J RUFENACHT, H FLORES, W AF GOFF, F GOFF, SJ KELKAR, S SHEVENELL, L TRUESDELL, AH MUSGRAVE, J RUFENACHT, H FLORES, W TI EXPLORATION DRILLING AND RESERVOIR MODEL OF THE PLATANARES GEOTHERMAL SYSTEM, HONDURAS, CENTRAL-AMERICA SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article ID VALLES CALDERA; NEW-MEXICO AB Results of drilling, logging, and testing of three exploration core holes, combined with results of geologic and hydrogeochemical investigations, have been used to present a reservoir model of the Platanares geothermal system, Honduras. Geothermal fluids circulate at depths greater-than-or-equal-to 1.5 km in a region of active tectonism devoid of Quaternary volcanism. Large, artesian water entries of 160 to 165-degrees-C geothermal fluid in two core holes at 625 to 644 m and 460 to 635 m depth have maximum flow rates of roughly 355 and 5601/min, respectively, which are equivalent to power outputs of about 3.1 and 5.1 MW(thermal). Dilute, alkali-chloride reservoir fluids (TDS less-than-or-equal-to 1200 mg/kg) are produced from fractured Miocene andesite and Cretaceous to Eocene redbeds that are hydrothermally altered. Fracture permeabillity in producing horizons is locally greater than 1500 md and bulk porosity is less-than-or-equal-to 6%. A simple, fracture-dominated, volume-impedance model assuming turbulent flow indicates that the calculated reservoir storage capacity of each flowing hole is approximately 9.7 x 10(6) 1/(kg cm-2). Tritium data indicate a mean residence time of 450 yr for water in the reservoir. Multiplying the natural fluid discharge rate by the mean residence time gives an estimated water volume of the Platanares system of greater-than-or-equal-to 0.78 km3. Downward continuation of a 139-degrees-C/km "conductive" gradient at a depth of 400 m in a third core hole implies that the depth to a 225-degrees-C source reservoir (predicted from chemical geothermometers) is at least 1.5 km. Uranium-thorium disequilibrium ages on calcite veins at the surface and in the core holes indicate that the present Platanares hydrothermal system has been active for the last 0.25 m.y. C1 SWISSBORING LTD,GUATEMALA CITY,GUATEMALA. EMPRESA NACL ENERGIA ELECT,UNIDAD PROYECTO GEOTERM,TEGUCIGALPA,HONDURAS. US GEOL SURVEY,IGNEOUS & GEOTHERMAL PROC BRANCH,MENLO PK,CA 94025. RP GOFF, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & SPACE SCI,LOS ALAMOS,NM 87545, USA. NR 30 TC 17 Z9 17 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 MAR PY 1991 VL 45 IS 1-2 BP 101 EP 123 DI 10.1016/0377-0273(91)90025-U PG 23 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000009 ER PT J AU JANIK, CJ TRUESDELL, AH GOFF, F SHEVENELL, L STALLARD, ML TRUJILLO, PE COUNCE, D AF JANIK, CJ TRUESDELL, AH GOFF, F SHEVENELL, L STALLARD, ML TRUJILLO, PE COUNCE, D TI A GEOCHEMICAL MODEL OF THE PLATANARES GEOTHERMAL SYSTEM, HONDURAS SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article ID WATERS AB Results of exploration drilling combined with results of geologic, geophysical, and hydrogeochemical investigations have been used to construct a geochemical model of the Platanares geothermal system, Honduras. Three core holes were drilled, two of which produced fluids from fractured Miocene andesite and altered Cretaceous to Eocene conglomerate at 450 to 680 m depth. Large-volume artesian flows of 160-165-degrees-C, predominantly bicarbonate water are chemically similar to, but slightly less saline than widespread boiling hot-spring waters. The chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells. Chemical, isotope, and gas geothermometers indicate a deep fluid temperature of 200 - 245-degrees-C and reflect a relatively short residence time in the fractures feeding the wells. Chloride-enthalpy relations as well as isotopic and chemical compositions of well discharges, thermal springs, and local cold waters support a conceptual model of ascending high-temperature (minimum 225-degrees-C) parent fluid that has cooled conductively to form the 160 - 165-degrees-C shallow (to 680 m) fluid encountered by the wells. The hot-spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid. The more dilute boiling spring waters (Cl = approximately 32 mg/kg) have cooled from > 225-degrees-C to about 160-degrees-C by conduction and from 160-degrees-C to 98-degrees-C by boiling. The most concentrated boiling spring waters (Cl = 37 mg/kg) have cooled from > 225-degrees-C to about 200-degrees-C by conduction and from 200-degrees-C to 98-degrees-C by boiling. Intermediate concentrations reflect mixed cooling paths. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & SPACE SCI,LOS ALAMOS,NM 87545. RP JANIK, CJ (reprint author), US GEOL SURVEY,IGNEOUS & GEOTHERMAL PROC BRANCH,MENLO PK,CA 94025, USA. NR 49 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR PY 1991 VL 45 IS 1-2 BP 125 EP 146 DI 10.1016/0377-0273(91)90026-V PG 22 WC Geosciences, Multidisciplinary SC Geology GA FE180 UT WOS:A1991FE18000010 ER PT J AU SAMANT, MG BROWN, CA GORDON, JG AF SAMANT, MG BROWN, CA GORDON, JG TI STRUCTURE OF AN ORDERED SELF-ASSEMBLED MONOLAYER OF DOCOSYL MERCAPTAN ON GOLD(111) BY SURFACE X-RAY-DIFFRACTION SO LANGMUIR LA English DT Letter ID GOLD AB We report here the first surface X-ray diffraction study of self-assembled monolayers on gold(111), providing new information about both in-plane and out-of-plane structure, and substantiating the high degree of order, both in the film and in its relation to the gold substrate. C1 BROOKHAVEN NATL LAB,NSLS,UPTON,NY 11973. RP SAMANT, MG (reprint author), IBM CORP,ALMADEN RES CTR,DIV RES,650 HARRY RD,SAN JOSE,CA 95120, USA. NR 12 TC 108 Z9 108 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAR PY 1991 VL 7 IS 3 BP 437 EP 439 DI 10.1021/la00051a001 PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FC988 UT WOS:A1991FC98800001 ER PT J AU SIRIWARDANE, RV AF SIRIWARDANE, RV TI X-RAY PHOTOELECTRON SPECTROSCOPIC INVESTIGATION OF OXIDATIVE COUPLING OF METHANE OVER SAMARIUM OXIDE PROMOTED WITH SODIUM PYROPHOSPHATE SO LANGMUIR LA English DT Article ID CATALYSTS; DIMERIZATION; ETHYLENE; OXYGEN AB Samarium oxide promoted with sodium pyrophosphate was found to be an active and selective catalyst for the oxidative coupling of methane to ethane and ethylene in the presence of molecular oxygen. C2 yields as high as 22% were obtained over Na4P2O7/Sm2O3 at 1101 K and the catalyst was stable during 23 h of reaction. Experimental conditions such as temperature, treatment with helium, dilution factor, and method of preparation affected the C2 selectivity and C2 yield. X-ray photoelectron spectroscopic (XPS) analysis indicated that the oxygen in Na4P2O7/Sm2O3 was in a more electron deficient state than in Sm2O3. More than one type of phosphorus was identified in Na4P2O7/Sm2O3 by XPS, which was different from that of Na4P2O7 in which only one type of phosphorus was present. The surface of the 0.5Na4P2O7/Sm2O3 prepared by the solid-state mixing method was found to be significantly different from that prepared by the solution deposition technique. RP SIRIWARDANE, RV (reprint author), US DOE,MORGANTOWN ENERGY TECHNOL CTR,POB 880,MORGANTOWN,WV 26507, USA. NR 17 TC 4 Z9 4 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAR PY 1991 VL 7 IS 3 BP 497 EP 502 DI 10.1021/la00051a014 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FC988 UT WOS:A1991FC98800014 ER PT J AU WELS, BR AUSTINHARRISON, DS JOHNSON, DC AF WELS, BR AUSTINHARRISON, DS JOHNSON, DC TI ELECTROCATALYTIC REDUCTION OF IODATE AT PLATINUM-ELECTRODES IN 0.5 M H2SO4 SO LANGMUIR LA English DT Article ID REAL CONDITION; OXIDATION; ACID AB Cyclic voltammetry at rotated disk electrodes was applied to a study of the electrocatalytic reduction of IO3- at Pt electrodes in 0.5 M H2SO4. Transient reduction of IO3- to I2,aq was observed to occur concomitantly with cathodic dissolution of surface oxide during the negative potential scan at a preanodized electrode. Furthermore, IO3- reduction at oxide-free Pt surfaces was determined to be very sensitive to the method applied for surface pretreatment. Hence, IO3-reduction at the oxide-free surfaces, previously concluded to occur by a homogeneously mediated process involving reduction of I2,aq generated by reaction of IO3- with I- in the diffusion layer, is now determined to have a strong electrocatalytic component. A mechanism is proposed in which IO3- is weakly associated to strongly adsorbed iodine (I0ads) on the oxide-free surface. This mechanism is very sensitive to the presence of adsorbed organic impurities originating from some cleaning materials. However, those impurities do not interfere with reduction of I2,aq, probably because of the stronger adsorption of I2 to the I0ads sites on the Pt surface. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. NR 24 TC 6 Z9 6 U1 2 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAR PY 1991 VL 7 IS 3 BP 559 EP 566 DI 10.1021/la00051a024 PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FC988 UT WOS:A1991FC98800024 ER PT J AU CHU, MT AF CHU, MT TI A CONTINUOUS JACOBI-LIKE APPROACH TO THE SIMULTANEOUS REDUCTION OF REAL MATRICES SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article ID SINGULAR VALUE DECOMPOSITION; SIMILARITY; ALGORITHM AB The problem of simultaneous reduction of real matrices by either orthogonal similarity or orthogonal equivalence transformations is considered. Based on the Jacobi idea of minimizing the sum of squares of the complementary part of the desired form to which matrices are reduced, the projected-gradient method is used in this paper. It is shown that the projected gradient of the objective function can be formulated explicitly. This gives rise to a system of ordinary differential equations that can be readily solved by numerical software. The advantages of this approach are that the desired form to which matrices are reduced can be almost arbitrary, and that if a desired form is not attainable, then the limit point of the corresponding differential equation gives a way of measuring the distance from the best reduced matrices to the nearest matrices that have the desired form. The general procedure for deriving these differential equations is discussed. The framework can be generalized to the complex-valued case. Some applications are given. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP CHU, MT (reprint author), N CAROLINA STATE UNIV,DEPT MATH,RALEIGH,NC 27695, USA. RI Chu, Moody/I-6663-2015 NR 30 TC 15 Z9 15 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 MAR PY 1991 VL 147 BP 75 EP 96 DI 10.1016/0024-3795(91)90230-T PG 22 WC Mathematics, Applied; Mathematics SC Mathematics GA EX022 UT WOS:A1991EX02200006 ER PT J AU ERDEMIR, A AF ERDEMIR, A TI TRIBOLOGICAL PROPERTIES OF BORIC-ACID AND BORIC-ACID-FORMING SURFACES .1. CRYSTAL-CHEMISTRY AND MECHANISM OF SELF-LUBRICATION OF BORIC-ACID SO LUBRICATION ENGINEERING LA English DT Article; Proceedings Paper CT 45TH ANNUAL MEETING OF THE SOC OF TRIBOLOGISTS AND LUBRICATION ENGINEERS CY MAY 07-10, 1990 CL DENVER, CO SP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS AB An in-depth understanding of the atomic-scale structure and chemistry of self-lubricating solids and how they relate to the efficiency and endurance of large-scale tribosystems is critically important. Of particular interest is the use of this understanding in developing mechanistic models that can increase our ability to assess and predict the capabilities of self-lubricating solids. Accordingly, a comprehensive investigation was conducted of the boric acid-forming surfaces. This paper describes the fundamentals of the crystal chemistry of boric acid and proposes a mechanism for its self-lubrication action. Pin-on-disk tests, performed on cold-pressed boric acid pins and AISI 52100 steel disks, showed that the friction coefficient of this tribosystem is approximately 0.1. The results of this investigation indicate that the boric acid, owing to its unique crystal structure and bond characteristics, is a promising solid lubricant for a wide range of tribological applications. RP ERDEMIR, A (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,TRIBOL SECT,ARGONNE,IL 60439, USA. NR 0 TC 68 Z9 68 U1 0 U2 7 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD MAR PY 1991 VL 47 IS 3 BP 168 EP 173 PG 6 WC Engineering, Mechanical SC Engineering GA FB303 UT WOS:A1991FB30300003 ER PT J AU ERDEMIR, A FENSKE, GR ERCK, RA NICHOLS, FA BUSCH, DE AF ERDEMIR, A FENSKE, GR ERCK, RA NICHOLS, FA BUSCH, DE TI TRIBOLOGICAL PROPERTIES OF BORIC-ACID AND BORIC-ACID-FORMING SURFACES .2. MECHANISMS OF FORMATION AND SELF-LUBRICATION OF BORIC-ACID FILMS ON BORON-CONTAINING AND BORIC OXIDE-CONTAINING SURFACES SO LUBRICATION ENGINEERING LA English DT Article; Proceedings Paper CT 45TH ANNUAL MEETING OF THE SOC OF TRIBOLOGISTS AND LUBRICATION ENGINEERS CY MAY 07-10, 1990 CL DENVER, CO SP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS AB This paper describes the mechanisms of formation and self-lubrication of boric acid films on boron- and boric oxide-containing surfaces. As reported in Part I, boric acid, owing to a triclinic, layered-crystal structure and weak interlayer bonds, exhibits unusual lubricating capability. Techniques of RF-magnetron sputtering and vacuum evaporation were used to produce thin coatings of boron and boric oxides on steel substrates. The results of tribological experiments indicate that the room-temperature friction coefficient of tribosystems that include boron and/or boric oxide coatings ranges from 0.05 to 0.07, depending on the coating type. Laser-Raman spectroscopy of the surfaces revealed that this low friction is associated with a thin boric acid film that spontaneously forms on the surfaces of these coatings. The fabrication and potential importance of boric acid and boric acid-forming surfaces for practical applications are enumerated. Surface engineering of tribomaterials, such as those demonstrated in this paper, is suggested as a new lubrication concept for present and future tribological industries. RP ERDEMIR, A (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,TRIBOL SECT,ARGONNE,IL 60439, USA. NR 0 TC 51 Z9 54 U1 1 U2 10 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD MAR PY 1991 VL 47 IS 3 BP 179 EP 184 PG 6 WC Engineering, Mechanical SC Engineering GA FB303 UT WOS:A1991FB30300004 ER PT J AU MOON, BM KORDAS, G VANHARLINGEN, DJ JENG, YL JOHNSON, DL SHARPE, PR GORETTA, K AF MOON, BM KORDAS, G VANHARLINGEN, DJ JENG, YL JOHNSON, DL SHARPE, PR GORETTA, K TI SINTER-FORGE PROCESS FOR PB,SB-DOPED 110 K BISRCACUO SUPERCONDUCTING PHASE SO MATERIALS LETTERS LA English DT Article ID CU-O SYSTEM AB High-T(c) phase (2-2-2-3) samples of Pb,Sb-doped BiSrCaCuO superconductors were fabricated by a sinter-forge technique. Calcined powders as well as pre-sintered pellets were sinter forged at 861-degrees-C in flowing oxygen with an initial pressure of 4.5 MPa for 3.5 h and subsequently annealed. Best sinter-forged samples exhibited a majority of 2-2-2-3 phase, highly-oriented plate-like grains, and high bulk density values. The effects of processing conditions on microstructures and the electrical properties were investigated. C1 NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. ARGONNE NATL LAB,ARGONNE,IL 60439. RP MOON, BM (reprint author), UNIV ILLINOIS,SCI & TECHNOL CTR SUPERCONDUCTIV,MAT RES LAB,URBANA,IL 61801, USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD MAR PY 1991 VL 10 IS 11-12 BP 481 EP 484 DI 10.1016/0167-577X(91)90211-N PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FF947 UT WOS:A1991FF94700002 ER PT J AU ENGELMANN, B AF ENGELMANN, B TI NIKE2D MODELS SEVERELY STRAINED DUCTILE METALS SO MECHANICAL ENGINEERING LA English DT Article RP ENGELMANN, B (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0025-6501 J9 MECH ENG JI Mech. Eng. PD MAR PY 1991 VL 113 IS 3 BP 48 EP 51 PG 4 WC Engineering, Mechanical SC Engineering GA FA145 UT WOS:A1991FA14500010 ER PT J AU GRIEVE, RAF BOTTOMLEY, RB BOUCHARD, MA ROBERTSON, PB ORTH, CJ ATTREP, M AF GRIEVE, RAF BOTTOMLEY, RB BOUCHARD, MA ROBERTSON, PB ORTH, CJ ATTREP, M TI IMPACT MELT ROCKS FROM NEW QUEBEC CRATER, QUEBEC, CANADA SO METEORITICS LA English DT Article AB Approximately 1500 g of float samples of impact melt rocks have been recovered from gravel deposits approximately 4 km north and northeast of the rim of the 3.4 km diameter New Quebec Crater (61-degrees 17'N; 73-degrees 40'W) in northern Quebec, Canada. Previously, only two small samples of impact melt rocks were known. The newly recovered samples have cryptocrystalline to microcrystalline matrices with microlites of andesine and pigeonite. Mineral clasts of quartz and feldspar occur and, in some cases, show shock metamorphic features. The melt rocks have a normative mineralogy corresponding to approximately 70% quartz, orthoclase and albite and are compositionally similar. Their major element composition can be modeled as a mix of granitic gneisses that make up the target rocks. The melt rocks show enrichments, however, in Cr (21 ppm), Co (9 ppm), Ni (12 ppm) and Ir (1.5 ppb) over the target rocks. Interelement ratios suggest a chondritic impacting body, although they do not define a specific type. Assuming a C-1 chondrite, the impact melt rocks average approximately 2% meteoritic contamination. Stepwise Ar-40-Ar-39 dating using a laser on three chips from three samples give integrated ages of 0.6-2.5 Ma. From the best plateau ages, the age of the New Quebec impact is taken to be 1.4 +/- 0.1 Ma, which places it before the first major northern hemisphere continental glaciation of the Pleistocene. A number of considerations suggest that the impact melt rocks were originally deposited in fractures in the crater wall and later transported to their discovery site by glacial ice and melt water. C1 CANADIAN UNION COLL 27,COLL HTS,ALBERTA,CANADA. UNIV MONTREAL,MONTREAL H3C 3J7,QUEBEC,CANADA. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. RP GRIEVE, RAF (reprint author), GEOL SURVEY CANADA,OTTAWA K1A 0E8,ONTARIO,CANADA. NR 30 TC 14 Z9 14 U1 2 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAR PY 1991 VL 26 IS 1 BP 31 EP 39 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FG532 UT WOS:A1991FG53200005 ER PT J AU PENNYCOOK, SJ AF PENNYCOOK, SJ TI IMAGING IN MATERIALS SCIENCE SO MRS BULLETIN LA English DT Editorial Material RP PENNYCOOK, SJ (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN, 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 MAR PY 1991 VL 16 IS 3 BP 19 EP 20 PG 2 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FD778 UT WOS:A1991FD77800003 ER PT J AU JESSON, DE PENNYCOOK, SJ AF JESSON, DE PENNYCOOK, SJ TI HIGH-RESOLUTION Z-CONTRAST IMAGING OF SEMICONDUCTOR INTERFACES SO MRS BULLETIN LA English DT Article RP JESSON, DE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN, USA. OI Jesson, David/0000-0003-0897-1445 NR 0 TC 4 Z9 4 U1 0 U2 1 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 MAR PY 1991 VL 16 IS 3 BP 34 EP 40 PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FD778 UT WOS:A1991FD77800006 ER PT J AU FELTON, JS KNIZE, MG AF FELTON, JS KNIZE, MG TI OCCURRENCE, IDENTIFICATION, AND BACTERIAL MUTAGENICITY OF HETEROCYCLIC AMINES IN COOKED FOOD SO MUTATION RESEARCH LA English DT Review DE HETEROCYCLIC AMINE; AMINO-IMIDAZOAZAARENES; MUTAGENS; AMES SALMONELLA ASSAY; COOKED FOODS; STRUCTURE ACTIVITY; ANALYTICAL CHEMISTRY ID FRIED GROUND-BEEF; AMES SALMONELLA TEST; MASS-SPECTROMETRY; LIQUID-CHROMATOGRAPHY; MONOCLONAL-ANTIBODIES; EFFICIENT EXTRACTION; POTENT MUTAGEN; COOKING; MEAT; PRODUCTS AB Potent mutagenic activity in Salmonella bacteria has been reported in cooked foods in numerous laboratories worldwide. Determining the human risk from exposure to these biologically active compounds in our diet requires genotoxic and carcinogenic evaluation of the chemicals coupled with determination of the dose consumed. Thus, knowledge of the exact structure of the mutagens present in the food and enough synthesized material for biological assessment are essential for this evaluation. To reach this goal, isolation of these compounds requires the Ames/Salmonella assay to guide the purification and identification process. Mass and NMR spectrometry are used to identify the isolated compounds. Finally, these findings are followed by synthesis of the exact isomer. The predominant class of mutagens found in cooked foods of the western diet are amino-imidazo-quinoxalines, amino-imidazo-pyridines and amino-imidazo-quinolines, collectively called amino-imidazoazaarenes (AIAs). Mass amounts of these specific compounds range from less than 1 to 70 ng/g of meat. The mutagens are formed from the heating of natural precursors (creatine, amino acids, and possibly sugars) in the food. These AIAs are some of the most potent mutagens ever tested in Salmonella bacteria with the number and position of methyl groups having an important influence on the mutagenic activity. RP FELTON, JS (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,POB 5507,LIVERMORE,CA 94550, USA. FU NIEHS NIH HHS [222YO1-ES-10063]; PHS HHS [40811] NR 51 TC 271 Z9 273 U1 1 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD MAR-APR PY 1991 VL 259 IS 3-4 BP 205 EP 217 DI 10.1016/0165-1218(91)90118-6 PG 13 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FH845 UT WOS:A1991FH84500002 PM 2017208 ER PT J AU JEGGO, PA TESMER, J CHEN, DJ AF JEGGO, PA TESMER, J CHEN, DJ TI GENETIC-ANALYSIS OF IONIZING-RADIATION SENSITIVE MUTANTS OF CULTURED MAMMALIAN-CELL LINES SO MUTATION RESEARCH LA English DT Article DE IONIZING RADIATION SENSITIVE MUTANTS; MAMMALIAN CELL LINES, CULTURED; HYBRIDS, CONSTRUCTION; HAT; OUABAIN ID HAMSTER OVARY CELL; MOUSE L5178Y CELLS; SUSPENSION SPOTTING METHOD; DNA-REPAIR; CHO CELLS; COMPLEMENTATION GROUPS; XERODERMA PIGMENTOSUM; IONIZING-RADIATION; CROSS-SENSITIVITY; DEFICIENT AB The genetic diversity of a range of ionising radiation sensitive mutants of cultured mammalian cell lines has been examined. Hybrids were constructed from suitably marked diploid cells by cell fusion and selected using resistance to HAT and ouabain. Hybrids were examined for ploidy and gamma-ray sensitivity. The data suggest that at least 8 and possibly 9 complementation groups exist which confer sensitivity to ionising radiation. Mutants in at least 3 distinct complementation groups have a reduced ability to rejoin DNA double-strand breaks. C1 UNIV CALIF LOS ALAMOS SCI LAB,GENET GRP,LOS ALAMOS,NM 87544. RP JEGGO, PA (reprint author), UNIV SUSSEX,MRC,CELL MUTAT UNIT,BRIGHTON BN1 9RR,ENGLAND. NR 33 TC 85 Z9 85 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD MAR PY 1991 VL 254 IS 2 BP 125 EP 133 DI 10.1016/0921-8777(91)90003-8 PG 9 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FB445 UT WOS:A1991FB44500003 PM 2002809 ER PT J AU TUCKER, JD JONES, NJ ALLEN, NA MINKLER, JL THOMPSON, LH CARRANO, AV AF TUCKER, JD JONES, NJ ALLEN, NA MINKLER, JL THOMPSON, LH CARRANO, AV TI CYTOGENETIC CHARACTERIZATION OF THE IONIZING RADIATION-SENSITIVE CHINESE-HAMSTER MUTANT IRSL SO MUTATION RESEARCH LA English DT Article DE CHINESE HAMSTER MUTANT IRSL; IRSL; MITOMYCIN-C; DECARBAMOYL MITOMYCIN-C; BROMODEOXYURIDINE; DNA REPAIR, CHROMOSOMAL ABERRATIONS ID ATAXIA TELANGIECTASIA LYMPHOCYTES; INDUCED CHROMOSOME-ABERRATIONS; SISTER-CHROMATID EXCHANGES; FANCONIS ANEMIA CELLS; MITOMYCIN-C; COMPLEMENTATION GROUP; DNA CROSSLINKING; X-IRRADIATION; REPAIR; RADIOSENSITIVITY AB The X-ray-sensitive mutant V79 cell line irs1 was characterized with respect to chromosomal aberrations induced by Cs-137, mitomycin C (MMC), and decarbamoyl mitomycin C (DCMMC). To measure chromosome damage induced at different cell cycle stages, irs1 and the parental V79-4 cell lines were pulse-labeled with bromodeoxyuridine (BrdUrd) at the time of exposure and harvested at various intervals corresponding to exposure in G1, S, and G2 phases of the cell cycle. Metaphase spreads were stained with an anti-BrdUrd antibody, followed by a fluorescein-conjugated second antibody. With propidium iodide as a counter stain, cells were scored for aberrations. Compared to the parental V79 cells, irs1 cells had: (1) greatly increased sensitivity to all 3 agents; (2) a high frequency of chromatid exchanges after exposure in each phase of the cell cycle; and (3) more sensitivity to the agent causing crosslinks (MMC) than its monofunctional analog (DCMMC). The finding of chromatid-type damage in cells exposed to ionizing radiation during G1 is atypical of normal cells, but is similar to observations made in several mutant rodent cell lines and in ataxia telangiectasia cells. Our results suggest that the defect in irs1 cells can manifest itself as misrepair or misreplication during all phases of the cell cycle and leads to a high incidence of chromatid exchanges and deletions. RP TUCKER, JD (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,POB 5507,L-452,LIVERMORE,CA 94551, USA. RI Jones, Nigel/D-1997-2010 NR 49 TC 48 Z9 48 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD MAR PY 1991 VL 254 IS 2 BP 143 EP 152 DI 10.1016/0921-8777(91)90005-A PG 10 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FB445 UT WOS:A1991FB44500005 PM 1900570 ER PT J AU WARTERS, RL LYONS, BW LI, TM CHEN, DJ AF WARTERS, RL LYONS, BW LI, TM CHEN, DJ TI TOPOISOMERASE-II ACTIVITY IN A DNA DOUBLE-STRAND BREAK REPAIR DEFICIENT CHINESE-HAMSTER OVARY CELL-LINE SO MUTATION RESEARCH LA English DT Article DE DNA DOUBLE-STRAND BREAK REPAIR; TOPOISOMERASE-II; CHINESE HAMSTER OVARY CELL LINE ID SISTER-CHROMATID EXCHANGES; RAY-SENSITIVE MUTANTS; CYTO-TOXICITY; L1210 CELLS; DAMAGE; NUCLEI; INHIBITORS; ACRIDINES; EXPOSURE; AGENTS AB Topoisomerase II activity was measured in wild-type, Chinese hamster ovary K1 cells, and in the DNA double-strand break repair deficient xrs-6 cell line. Total topoisomerase II activity in a high salt, nuclear extract was found to be the same in both cell lines, as measured by decatenation of kinetoplast DNA networks and catenation of plasmid pBR322 DNA. While at low drug concentrations m-AMSA-induced enzyme cutting of nuclear DNA was 25% less in xrs-6 cells, the frequency of DNA breaks at high concentrations of the drug, and thus the frequency of the topoisomerase II enzyme, was the same in both cell lines. Despite the presence of equivalent enzyme levels in both cell lines, the xrs-6 cell line was 3 times more sensitive to drug-induced cytotoxicity. These results may be due to the fact that, as with X-radiation-induced DNA damage, xrs-6 cells are deficient in the capacity to rejoin topoisomerase II-induced DNA double-strand breaks. C1 UNIV CALIF LOS ALAMOS SCI LAB,GENET GRP,LOS ALAMOS,NM 87545. RP WARTERS, RL (reprint author), UNIV UTAH,HLTH SCI CTR,DEPT RADIOL,SALT LAKE CITY,UT 84132, USA. FU NCI NIH HHS [CA45154] NR 25 TC 16 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD MAR PY 1991 VL 254 IS 2 BP 167 EP 174 DI 10.1016/0921-8777(91)90008-D PG 8 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FB445 UT WOS:A1991FB44500008 PM 1848351 ER PT J AU MCCARTHY, JF GARDNER, H WOLFE, MJ SHUGART, LR AF MCCARTHY, JF GARDNER, H WOLFE, MJ SHUGART, LR TI DNA ALTERATIONS AND ENZYME-ACTIVITIES IN JAPANESE MEDAKA (ORYZIAS-LATIPES) EXPOSED TO DIETHYLNITROSAMINE SO NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS LA English DT Article; Proceedings Paper CT SYMP ON ANIMAL-TO-HUMAN EXTRAPOLATION : ISSUES AND OPPORTUNITIES CY MAR 13-15, 1990 CL SAN ANTONIO, TX SP UNIV TEXAS SAN ANTONIO, COLL SCI & ENGN, DIV LIFE SCI, USAF, DIV HUMAN SYST, MED READINESS ADV DEV OFF, USAF, SCH AEROSP MED, DIV RADIAT SCI, SYST RES LAB, USN, MED RES & DEV COMMAND DE MEDAKA; GENOTOXICITY; DNA ALTERATIONS; DETOXIFYING ACTIVITIES; DNA STRAND BREAKS; 5'-METHYLDEOXYCYTIDINE; FLOW CYTOMETERY; DIETHYLNITROSAMINE ID QUANTITATION; ASSAY AB Several molecular and biochemical markers of genotoxicity were adapted for measurement in the medaka, and were used to describe the effects of treatment of the organism with diethylnitrosamine (DEN). DEN treatment inhibited the activity of a detoxication enzyme activity (ethoxyresorufin-O-deethylase) and increased the activity of glutathione-S-transferase. This pattern of response has been described in preneoplastic rodent cells. No O6-ethyl guanine adducts were detected, and a slight, but statistically significant, increase in DNA strand breaks was observed. These results are consistent with the hypothesis that prolonged exposure to high levels of DEN induced alkyltransferase activity which enzymatically removes any O6-ethyl guanine adducts but does not result in strand breaks or hypomethylation of the DNA such as might be expected from excision repair of chemically modified DNA. C1 USA,BIOMED RES & DEV LAB,DIV HLTH EFFECTS RES,FT DETRICK,MD 21701. EXPTL PATHOL LABS INC,HERNDON,VA 22070. RP MCCARTHY, JF (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008-6036,OAK RIDGE,TN 37831, USA. NR 15 TC 6 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0149-7634 J9 NEUROSCI BIOBEHAV R JI Neurosci. Biobehav. Rev. PD SPR PY 1991 VL 15 IS 1 BP 99 EP 102 DI 10.1016/S0149-7634(05)80099-5 PG 4 WC Behavioral Sciences; Neurosciences SC Behavioral Sciences; Neurosciences & Neurology GA FC484 UT WOS:A1991FC48400017 PM 2052206 ER PT J AU KWONG, MK AF KWONG, MK TI UNIQUENESS RESULTS FOR EMDEN-FOWLER BOUNDARY-VALUE-PROBLEMS SO NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS LA English DT Article DE REACTION DIFFUSION EQUATION; BOUNDARY VALUE PROBLEM; UNIQUENESS OF POSITIVE RADIAL SOLUTION; SULFATE, MULTICENTRIC CLINICAL STUDIES ID POSITIVE SOLUTIONS; EQUATIONS; RN RP KWONG, MK (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439, USA. NR 17 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0362-546X J9 NONLINEAR ANAL-THEOR JI Nonlinear Anal.-Theory Methods Appl. PD MAR PY 1991 VL 16 IS 5 BP 435 EP 454 DI 10.1016/0362-546X(91)90069-D PG 20 WC Mathematics, Applied; Mathematics SC Mathematics GA FA376 UT WOS:A1991FA37600003 ER PT J AU CHATTERS, JC NEITZEL, DA SCOTT, MJ SHANKLE, SA AF CHATTERS, JC NEITZEL, DA SCOTT, MJ SHANKLE, SA TI POTENTIAL IMPACTS OF GLOBAL CLIMATE CHANGE ON PACIFIC-NORTHWEST SPRING CHINOOK SALMON (ONCORHYNCHUS-TSHAWYTSCHA) - AN EXPLORATORY CASE-STUDY SO NORTHWEST ENVIRONMENTAL JOURNAL LA English DT Article AB Increases in atmospheric concentrations of greenhouse gases are predicted to raise global temperatures by up to 3-degrees-C over the next one-hundred years, which may have significant effects on natural resources. Even a smaller (2-degrees-C) temperature change may impact one prominent Pacific Northwest natural resource, the spring chinook salmon, Oncorhynchus tshawytscha. A computer model was developed by the Northwest Power Planning Council (NPPC) for use in developing the NPPC salmon enhancement plan for their Fish and Wildlife Program. Using this model, we investigate the impact of global warming on the production of spring chinook salmon in the Yakima subbasin of the Columbia River System. The model simulates current prevailing environmental conditions and the implementation of improvements in salmon habitat planned by the NPPC. The data are then changed to reflect conditions that we infer to have existed between 6,000 and 8,000 years ago, when temperatures were approximately 2-degrees-C warmer than today. When the NPPC computer model is run under these altered conditions, it shows that projected climate change might reduce by half the Yakima River spring chinook salmon production predicted under both current and NPPC-improved conditions. These results strongly support the need for planned improvements in the fishery, since a 50% decline in existing fish populations could decrease spring chinook salmon-and possibly other salmonid populations-beneath levels needed for the survival of the species. More broadly, the results suggest that if future global warming takes a form similar to that of 6,000 years ago, it could have major effects on the salmon population of the Pacific Northwest. Although some races of salmon might have their survival enhanced, others might be harmed. We recognize that all species and races would not be affected in the same way as Yakima River spring chinook, yet global warming is still a matter of concern because many of the Pacific Northwest salmon stocks are already under stress from other causes. A more comprehensive and thorough analysis is urgently needed. RP CHATTERS, JC (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 0 TC 13 Z9 13 U1 4 U2 15 PU INST ENVIRON STUD PI SEATTLE PA UNIV WASHINGTON ENGINEERING ANNEX FM-12, SEATTLE, WA 98195 SN 0749-7962 J9 NORTHWEST ENVIRON J PD SPR-SUM PY 1991 VL 7 IS 1 BP 71 EP 92 PG 22 WC Ecology; Environmental Sciences; Forestry SC Environmental Sciences & Ecology; Forestry GA GL340 UT WOS:A1991GL34000003 ER PT J AU NOWLEN, SP LAMBRIGHT, JA ROMIG, JC BOHN, MP NICOLETTE, VF AF NOWLEN, SP LAMBRIGHT, JA ROMIG, JC BOHN, MP NICOLETTE, VF TI A DISCUSSION OF FIRE SUPPRESSION INDUCED EQUIPMENT DAMAGE AND SYSTEMS IMPACT THROUGH AN EXAMINATION OF SPURIOUS FIRE SUPPRESSION ACTUATION INCIDENTS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT POST-CONF SEMINAR ON FIRE SAFETY IN NUCLEAR PLANTS CY AUG 21-25, 1989 CL ANAHEIM, CA AB This paper will discuss current work associated with the investigation of equipment damage induced by the application of fire suppressants. This discussion will be presented through an examination of several nuclear power plant incidents in which the spurious actuation of one or more fire suppression systems has occurred. The effects of these actuations on plant equipment, systems, and operation will be described. Also presented are the results of scoping calculations of the risk significance of spurious suppression system actuation. Finally, the paper will provide a description of efforts recommended to further investigate the impact of such incidents on plant operations and plant risk. RP NOWLEN, SP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 2 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 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAR PY 1991 VL 125 IS 3 BP 309 EP 314 DI 10.1016/0029-5493(91)90336-G PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FK786 UT WOS:A1991FK78600004 ER PT J AU GREGORY, WS MARTIN, RA WHITE, BW NICHOLS, BD SMITH, PR LESLIE, IH FENTON, DL GUNAJI, MV BLYTHE, JP AF GREGORY, WS MARTIN, RA WHITE, BW NICHOLS, BD SMITH, PR LESLIE, IH FENTON, DL GUNAJI, MV BLYTHE, JP TI FIRES IN LARGE-SCALE VENTILATION SYSTEMS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT POST-CONF SEMINAR ON FIRE SAFETY IN NUCLEAR PLANTS CY AUG 21-25, 1989 CL ANAHEIM, CA AB This paper summarizes the experience gained simulating fires in large scale ventilation systems patterned after ventilation systems found in nuclear fuel cycle facilities. The series of experiments discussed includes: (1) combustion aerosol loading of 0.61 x 0.61m HEPA filters with the combustion products of two organic fuels, polystyrene and polymethylemethacrylate; (2) gas dynamic and heat transport through a large scale ventilation system consisting of a 0.61 x 0.61 m duct 90 m in length, with dampers, HEPA filters, blowers, etc.; (3) gas dynamic and simultaneous transport of heat and solid particulate (consisting of glass beads with a mean aerodynamic diameter of 10-mu) through the large scale ventilation system; and (4) the transport of heat and soot, generated by kerosene pool fires, through the large scale ventilation system. The FIRAC computer code, designed to predict fire-induced transients in nuclear fuel cycle facility ventilation systems, was used to predict the results of experiments (2) through (4). In general, the results of the predictions were satisfactory. The code predictions for the gas dynamics, heat transport, and particulate transport and deposition were within 10% of the experimentally measured values. However, the code was less successful in predicting the amount of soot generation from kerosene pool fires, probably due to the fire module of the code being a one-dimensional zone model. The experiments revealed a complicated three-dimensional combustion pattern within the fire room of the ventilation system. Further refinement of the fire module within FIRAC is needed. C1 NEW MEXICO STATE UNIV,LAS CRUCES,NM 88003. RP GREGORY, WS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 12 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAR PY 1991 VL 125 IS 3 BP 337 EP 345 DI 10.1016/0029-5493(91)90340-N PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FK786 UT WOS:A1991FK78600008 ER PT J AU NICOLETTE, VF NOWLEN, SP AF NICOLETTE, VF NOWLEN, SP TI FIRE MODELS FOR ASSESSMENT OF NUCLEAR-POWER-PLANT FIRES SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT POST-CONF SEMINAR ON FIRE SAFETY IN NUCLEAR PLANTS CY AUG 21-25, 1989 CL ANAHEIM, CA AB This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plant fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. RP NICOLETTE, VF (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAR PY 1991 VL 125 IS 3 BP 389 EP 394 DI 10.1016/0029-5493(91)90347-K PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FK786 UT WOS:A1991FK78600015 ER PT J AU TRAVIS, JR GREGORY, WS KRAUSE, FR AF TRAVIS, JR GREGORY, WS KRAUSE, FR TI LOS-ALAMOS COMBUSTION MODELING FOR NUCLEAR SYSTEMS SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT POST-CONF SEMINAR ON FIRE SAFETY IN NUCLEAR PLANTS CY AUG 21-25, 1989 CL ANAHEIM, CA ID STRONG IGNITION; FLAMES; WEAK AB The occurrence of severe fire accidents in nuclear systems has resulted in research activities to model combustion phenomena in these systems. A combustion analysis of an entire facility is needed to determine the transient pressure and heating loads on the containment or ventilation structures and safety-related equipment, to plan emergency evacuation, to validate existing fire protection programs or suggest changes, and to integrate fire safety with other safety analysis requirements. The first part of this paper reviews traditional fire analysis methods and identifies capabilities that can be retained for modeling nuclear facilities. Additional capabilities are outlined that will be needed to accomodate the unique architecture and design-basis accidents of nuclear facilities. In later sections, the Los Alamos modeling approach for both nonreactor and reactor systems is presented. RP TRAVIS, JR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV NUCL TECHNOL & ENGN,LOS ALAMOS,NM 87545, USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAR PY 1991 VL 125 IS 3 BP 403 EP 410 DI 10.1016/0029-5493(91)90349-M PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FK786 UT WOS:A1991FK78600017 ER PT J AU SCHNEIDER, U MULLER, K GREGORY, WS LIEMERSDORF, H AF SCHNEIDER, U MULLER, K GREGORY, WS LIEMERSDORF, H TI SMIRT-10 POST-CONFERENCE SEMINAR NO. 6 - FIRE SAFETY IN NUCLEAR-POWER-PLANTS AUGUST 21-22, 1989, ANAHEIM, CALIFORNIA, USA - PREFACE SO NUCLEAR ENGINEERING AND DESIGN LA English DT Editorial Material C1 KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH,W-7500 KARLSRUHE 1,GERMANY. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. GESELL REAKTORSICHERHEIT GMBH,SCHWERTNERGASSE 1,W-5000 COLOGNE 1,GERMANY. RP SCHNEIDER, U (reprint author), TECH UNIV VIENNA,SEESTR 23,W-3503 LOHFELDEN,GERMANY. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAR PY 1991 VL 125 IS 3 BP R1 EP R1 DI 10.1016/0029-5493(91)90333-D PG 1 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FK786 UT WOS:A1991FK78600001 ER PT J AU HEWETT, DW KRUER, WL BANGERTER, RO AF HEWETT, DW KRUER, WL BANGERTER, RO TI CORONA PLASMA INSTABILITIES IN HEAVY-ION FUSION-TARGETS SO NUCLEAR FUSION LA English DT Article ID BEAM AB Several plasma instabilities driven by a heavy ion beam impinging on a target are considered. Potential instabilities include longitudinal electrostatic (two-stream) instabilities and transverse electromagnetic (filamentation or Weibel) instabilities. Since the ion beam may be accompanied by electrons, both electron beam and ion beam instabilities are considered. The electrostatic beam instabilities saturate by formation of an electron tail. In this paper the filamentation instability driven by this electron energy anisotropy is shown to be benign; this confirms the results of earlier studies in which the slower ion filamentation instability was shown to be unimportant. The beam ion, target electron instability is found to be suppressed by the gradient in the target density. Moreover, even if it were to grow, it would saturate at a benign level. In conclusion, no significant problem due to corona plasma instabilities in heavy ion fusion applications has been found. RP HEWETT, DW (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 22 TC 8 Z9 8 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAR PY 1991 VL 31 IS 3 BP 431 EP 446 DI 10.1088/0029-5515/31/3/003 PG 16 WC Physics, Fluids & Plasmas SC Physics GA FC321 UT WOS:A1991FC32100003 ER PT J AU SANCHEZ, JJ UPADHYE, RS AF SANCHEZ, JJ UPADHYE, RS TI NONDESTRUCTIVE METHOD FOR MEASURING THE D2/DT FILL PRESSURE AND PERMEABILITY FOR DIRECT DRIVE PLASTIC SHELLS SO NUCLEAR FUSION LA English DT Article AB A technique has been developed which makes it possible to measure in a non-destructive way the fill pressure of a transparent direct drive fusion shell. The accuracy of these measurements is within 2% of the best known values for the system D2/DT. By raising the temperature of the shells and allowing them to leak for a certain time between the pressure measurements, their leak rate and permeability can be determined accurately. The technique is simple emough to be used as a tool for quality control to eliminate shells with a leak rate faster than that set by established standards; the surviving shells will then be automatically characterized regarding their fill pressure and their leak rate. RP SANCHEZ, JJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 3 TC 2 Z9 6 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAR PY 1991 VL 31 IS 3 BP 459 EP 464 DI 10.1088/0029-5515/31/3/005 PG 6 WC Physics, Fluids & Plasmas SC Physics GA FC321 UT WOS:A1991FC32100005 ER PT J AU REDI, MH BATEMAN, G AF REDI, MH BATEMAN, G TI TRANSPORT SIMULATIONS OF TFTR EXPERIMENTS TO TEST THEORETICAL-MODELS FOR CHI-E AND CHI-I SO NUCLEAR FUSION LA English DT Article ID ANOMALOUS THERMAL CONFINEMENT; GRADIENT-DRIVEN TURBULENCE; TOKAMAK TRANSPORT; CODE; ELECTRON; BALDUR AB Predictions with the 1 1/2-D BALDUR transport code, using recent theory based models for thermal and particle transport, are compared with measured profiles of electron plasma density and electron and ion temperatures for Ohmic, L-mode and supershot discharges on TFTR. The profile consistent drift wave model is found to overestimate the ion temperatures at high heating powers so that a third mode or loss process is needed in addition to drift wave transport (trapped electron mode and eta-i mode) and an edge loss model. None of several versions of the local multiple mode models, using the 1989 Carreras-Diamond resistive ballooning mode, gives T(e), T(i) within 20% for all three TFTR regimes studied. RP REDI, MH (reprint author), PRINCETON PLASMA PHYS LAB,PRINCETON,NJ, USA. NR 36 TC 13 Z9 13 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAR PY 1991 VL 31 IS 3 BP 547 EP 559 DI 10.1088/0029-5515/31/3/013 PG 13 WC Physics, Fluids & Plasmas SC Physics GA FC321 UT WOS:A1991FC32100013 ER PT J AU WERLEY, KA AF WERLEY, KA TI REVERSED FIELD PINCH IGNITION REQUIREMENTS SO NUCLEAR FUSION LA English DT Article ID ENERGY CONFINEMENT AB Plasma models are described and used to calculate numerically the transport confinement (n-tau-E) requirements and steady state operation points for both the reversed field pinch (RFP) and the tokamak. The models are used to examine the CIT tokamak ignition conditions and the RFP experimental and ignition conditions. Physics differences between RFPs and tokamaks and their consequences for a D-T ignition machine are discussed. Compared with a tokamak, the ignition RFP has many physics advantages, including Ohmic heating to ignition (no need for auxiliary heating systems), higher beta, lower ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits) and successful operation with high radiation fractions (f(RAD) approximately 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic fields, larger aspect ratios and smaller plasma cross-sections, translate to significant cost reductions for both ignition and reactor applications. The primary drawback of the RFP is the uncertainty that the present scaling will extrapolate to reactor regimes. Devices that are under construction should go a long way towards resolving this scaling uncertainty. The 4 MA ZTH is expected to extend the n-tau-E transport scaling data by three orders of magnitude above the results of ZT-40M, and, if the present scaling holds, ZTH is expected to achieve a D-T equivalent scientific energy breakeven, Q = 1. A base case RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. RP WERLEY, KA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 20 TC 7 Z9 7 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAR PY 1991 VL 31 IS 3 BP 567 EP 582 DI 10.1088/0029-5515/31/3/015 PG 16 WC Physics, Fluids & Plasmas SC Physics GA FC321 UT WOS:A1991FC32100015 ER PT J AU BERTSCHE, KJ AF BERTSCHE, KJ TI ION MOTION IN A SMALL LOW-ENERGY CYCLOTRON SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID RADIOCARBON AB A small cyclotron (the "cyclotrino") was proposed for direct detection of radiocarbon in 1980 and has now detected radiocarbon at natural abundance. High resolution and background rejection are achieved in this cyclotron by acceleration of negative ions through many turns while operating at a high harmonic. This article details the analysis of ion motion in a small flat-field, electrostatically-focused cyclotron. Included are discussions of beam acceptance, axial and radial beam stability, and a detailed analysis of phase bunching and its effect on mass resolution. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NR 24 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1991 VL 301 IS 2 BP 171 EP 181 DI 10.1016/0168-9002(91)90457-2 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE937 UT WOS:A1991FE93700001 ER PT J AU XI, J HOLLINGSWORTH, RE BUITRAGO, RH OAKLEY, D CUMALAT, JP NAUENBERG, U MCNEIL, JA ANDERSON, DF PEREZMENDEZ, V AF XI, J HOLLINGSWORTH, RE BUITRAGO, RH OAKLEY, D CUMALAT, JP NAUENBERG, U MCNEIL, JA ANDERSON, DF PEREZMENDEZ, V TI MINIMUM IONIZING PARTICLE-DETECTION USING AMORPHOUS-SILICON DIODES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SIGNAL AB Hydrogenated amorphous silicon pin diodes have been used to detect minimum ionizing electrons with a pulse height signal-to-noise ratio exceeding 3. A distinct signal was seen for shaping times from 100 to 3000 ns. The devices used had a 54-mu-m thick intrinsic layer and an active area of 0.1 cm2. The maximum signal was 3200 electrons with a noise width of 950 electrons for a shaping time of 250 ns. C1 GLASSTECH SOLAR INC,WHEAT RIDGE,CO 80033. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. COLORADO SCH MINES,DEPT PHYS,GOLDEN,CO 80401. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 8 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1991 VL 301 IS 2 BP 219 EP 222 DI 10.1016/0168-9002(91)90462-Y PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE937 UT WOS:A1991FE93700006 ER PT J AU CARPENTER, JM MILDNER, DFR RICHARDSON, JW AF CARPENTER, JM MILDNER, DFR RICHARDSON, JW TI CORRECTING TIME-OF-FLIGHT NEUTRON-DIFFRACTION DATA FOR CHOPPED DELAYED NEUTRON BACKGROUNDS - THE ACTION OF A DRUM CHOPPER IN A PULSED NEUTRON BEAM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Delayed neutron choppers in pulsed source neutron beams serve to reduce the background caused by delayed neutrons in pulsed source instruments. We analyze the effect of a drum chopper placed in an incident pulsed beam which contains delayed neutrons and compute its influenced on the detector counting rate. Expressions are found for the time and wavelength dependence of the counting rates for both prompt and delayed neutrons, in both the monitor and the scattered neutron detectors. On the basis of these results, an exact method for determining the delayed neutron background is suggested for use in measuring and correcting pulsed-source diffractometer data, by operating the chopper in random phase with respect to the source. Other approximate methods are investigated. We report measurements which confirm the analysis. C1 NATL INST STAND & TECHNOL,CTR ANALYT CHEM,GAITHERSBURG,MD 20899. RP CARPENTER, JM (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1991 VL 301 IS 2 BP 305 EP 314 DI 10.1016/0168-9002(91)90473-4 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE937 UT WOS:A1991FE93700017 ER PT J AU CARPENTER, JM MILDNER, DFR AF CARPENTER, JM MILDNER, DFR TI TRANSMISSION PROBABILITY OF A DRUM CHOPPER IN A THERMAL-NEUTRON BEAM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Drum choppers have been placed in the incident beams of the pulsed source instruments at IPNS (Intense Pulsed Neutron Source) in order to reduce the background resulting from delayed neutrons from the booster target. Expressions are derived for the detailed pulse shape of the transmitted neutrons and for the duration of the chopper pulse. The transmission probability depends on the neutron wavelength, the frequency of rotation of the chopper, the chopper diameter and slot width, and the incident neutron beam width. These expressions are used to compute the transmission probabilities of time-of-flight diffractometers on pulsed neutron sources which employ drum choppers. They can also be used to determine the time and wavelength dependence of the counting rates for both prompt and delayed neutrons. C1 NATL INST STAND & TECHNOL,CTR ANALYT CHEM,GAITHERSBURG,MD 20899. RP CARPENTER, JM (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 4 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1991 VL 301 IS 2 BP 315 EP 327 DI 10.1016/0168-9002(91)90474-5 PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE937 UT WOS:A1991FE93700018 ER PT J AU BERTSCHE, KJ KARADI, CA MULLER, RA AF BERTSCHE, KJ KARADI, CA MULLER, RA TI RADIOCARBON DETECTION WITH A SMALL LOW-ENERGY CYCLOTRON SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SPHERICAL-ABERRATION; ELECTROSTATIC ACCELERATORS; NEGATIVE-IONS; LENSES; FIELD; FOILS AB A small cyclotron (the "cyclotrino") was proposed for direct detection of radiocarbon in 1980. This combined the suppression of background through the use of negative ions, which had been used effectively in tandem accelerators, with the high intrinsic mass resolution of a cyclotron. Development of a small electrostatically-focused cyclotron for use as a mass spectrometer was previously reported but the sensitivity needed for detection of C-14 at natural abundance was not achieved. A high current external ion source has now been integrated with a small flat-field, electrostatically-focused cyclotron to comprise a system capable of measuring C-14 at natural levels. The carbon ion beam from the ion source is preseparated with a Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-gated output. The design and performance of this system are presented here. In its present form the system is capable of improving the sensitivity of detecting C-14 in some biomedical experiments by a factor of 10(4). Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes, such as H-3, Be-10, and Al-26, are discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 52 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1991 VL 301 IS 2 BP 358 EP 371 DI 10.1016/0168-9002(91)90479-A PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE937 UT WOS:A1991FE93700023 ER PT J AU ROBERTS, ML MOORE, TL HORNADY, RS DAVIS, JC AF ROBERTS, ML MOORE, TL HORNADY, RS DAVIS, JC TI DISTRIBUTED COMPUTER CONTROL AT THE LLNL TANDEM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON NUCLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS CY FEB 05-09, 1990 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP UNIV MELBOURNE, SCH PHYS, EG & G ORETEC, ICI AUSTR RES, ELECTROSTAT INT, DYER ENERG SYST, MICRO ANAL RES CTR HO UNIV MELBOURNE AB Livermore is developing hardware and software tools to provide automated operation of an FN tandem accelerator. Automated operation is planned for several nuclear analytical techniques including hydrogen depth profiling and accelerator mass spectrometry. The control system utilizes a distributed computer system to provide 16 bit precision in control of accelerator power supplies. RP ROBERTS, ML (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,CTR ACCELERATOR MASS SPECT,LIVERMORE,CA 94550, USA. NR 4 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 1 EP 6 DI 10.1016/0168-583X(91)95480-2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100002 ER PT J AU ALTON, GD READ, PM AF ALTON, GD READ, PM TI EMITTANCE MEASUREMENTS OF GALLIUM LIQUID-METAL ION SOURCES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON NUCLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS CY FEB 05-09, 1990 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP UNIV MELBOURNE, SCH PHYS, EG & G ORETEC, ICI AUSTR RES, ELECTROSTAT INT, DYER ENERG SYST, MICRO ANAL RES CTR HO UNIV MELBOURNE ID EMISSION CHARACTERISTICS; ENERGY-DISTRIBUTION; IMPLANTATION; SI; MECHANISM; ELECTRON; SYSTEM; BEAMS AB The emittances of momentum-analyzed Ga-69+ ion beams extracted from a needle-type liquid-metal ion source (LMIS) are found to be approximately twice as large in the dispersive plane (x-direction) as in the orthogonal, nondispersive plane (y-direction). This effect is principally attributable to dispersion of the beam in the x-direction by the mass analyzing magnet used in the experiments. This dispersion results from space-charge effects and other sources of intrinsic energy spread within the ion beams. In addition, the growth of emittance with beam intensity is less dramatic in the y direction, also suggesting the effect of energy dispersion. It is argued that y-direction emittance values should be considered as representative of the gallium LMIS whenever energy dispersive devices are not incorporated in the beam transport system. Brief descriptions of the experimental hardware are given and x- and y-direction emittance data are presented in this report. C1 VG ISOTOPES LTD,WINSFORD CW7 3BX,CHESHIRE,ENGLAND. RP ALTON, GD (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 37 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 7 EP 11 DI 10.1016/0168-583X(91)95481-R PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100003 ER PT J AU LEFEVRE, HW SCHOFIELD, RMS CIARLO, DR AF LEFEVRE, HW SCHOFIELD, RMS CIARLO, DR TI THIN SI3N4 WINDOWS FOR ENERGY-LOSS STIM IN AIR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON NUCLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS CY FEB 05-09, 1990 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP UNIV MELBOURNE, SCH PHYS, EG & G ORETEC, ICI AUSTR RES, ELECTROSTAT INT, DYER ENERG SYST, MICRO ANAL RES CTR HO UNIV MELBOURNE ID RAY AB The use of thin (102 nm) windows of Si3N4 to transmit an electronically rastered microbeam of MeV protons into ambient air with small scattering is reported. The windows were made by anisotropic etching of Si, exposing about 1 mm2 of silicon nitride film integrally attached to a silicon supporting frame. Stress measurements on films of several thicknesses yielded a value of Young's modulus of 350 GPa. Energy loss scanning transmission ion micrographs of several small living animals are presented. Focused beams of 100 pA have been passed through the films without failure. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP LEFEVRE, HW (reprint author), UNIV OREGON,DEPT PHYS,EUGENE,OR 97403, USA. NR 10 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 47 EP 51 DI 10.1016/0168-583X(91)95489-Z PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100011 ER PT J AU DOYLE, BL WALSH, DS LEE, SR AF DOYLE, BL WALSH, DS LEE, SR TI EXTERNAL MICRO-ION-BEAM ANALYSIS (X-MIBA) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON NUCLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS CY FEB 05-09, 1990 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP UNIV MELBOURNE, SCH PHYS, EG & G ORETEC, ICI AUSTR RES, ELECTROSTAT INT, DYER ENERG SYST, MICRO ANAL RES CTR HO UNIV MELBOURNE ID PIXE ANALYSIS; ELEMENTAL ANALYSIS; PROTON MICROPROBE; SENSITIVITY; DEUTERIUM; LIMITERS; AIR AB In-air or external ion-beam analysis combined with 10-100-mu-m spatial resolution, is a truly unique feature of the nuclear microprobe technique. PIXE has been performed externally for many years, but, recently, other IBA techniques such as backscattering and nuclear reaction depth profiling measurements have been made in air. Presently, the use of external micro-ion-beam analysis, or X-MIBA, is being attempted at a growing number of microprobe facilities; however, the full potential of this new technique remains relatively unexploited. This paper will review the X-MIBA technique with emphasis on (1) optimization of exit foil geometries, (2) beam focusing and spot size considerations, (3) external IBA techniques, and (4) radiation hazards associated with the direct and scattered beam, nuclear reaction products and radionuclei production in the air. The unique in-air analysis advantages of no pump down, and essentially unrestricted sample size or state (solid, liquid etc.), has resulted in a myriad of applications of this technique at Sandia, which are featured as examples. C1 IDAHO STATE UNIV,POCATELLO,ID 83209. RP DOYLE, BL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 52 TC 23 Z9 24 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 244 EP 257 DI 10.1016/0168-583X(91)95521-E PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100043 ER PT J AU ANTOLAK, AJ PONTAU, AE AF ANTOLAK, AJ PONTAU, AE TI ON DATA REDUCTION ERRORS IN PROTON ENERGY-LOSS MEASUREMENTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 2ND INTERNATIONAL CONF ON NUCLEAR MICROPROBE TECHNOLOGY AND APPLICATIONS CY FEB 05-09, 1990 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP UNIV MELBOURNE, SCH PHYS, EG & G ORETEC, ICI AUSTR RES, ELECTROSTAT INT, DYER ENERG SYST, MICRO ANAL RES CTR HO UNIV MELBOURNE AB Numerical reconstructions of multiple proton energy loss (PEL) density projections produce three-dimensional spatial maps of density variations resulting from sample morphology and composition. The accuracy in evaluating the line-average density along each projection is directly correlated to the accuracy of the approximations used in the data reduction before reconstruction. Sources of data reduction errors including beam stopping power, energy straggling, Bragg additivity and energy loss curve fitting are discussed. Simulated tomographic data of uniform samples are generated on the computer to examine these errors in worst-case scenarios. The error analysis serves to help achieve improved material characterization by ion tomography. RP ANTOLAK, AJ (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94551, USA. NR 9 TC 4 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 371 EP 377 DI 10.1016/0168-583X(91)95539-P PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100061 ER PT J AU PONTAU, AE ANTOLAK, AJ MORSE, DH WEIRUP, DL AF PONTAU, AE ANTOLAK, AJ MORSE, DH WEIRUP, DL TI MINIMUM DATA SET REQUIREMENTS FOR ION MICROTOMOGRAPHY SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID COMPUTED-TOMOGRAPHY; PROTON AB Data acquisition and analysis rates and data set size seriously affect the practicality of conducting ion microtomography studies that map out material densities of extended objects in three dimensions. For the promise of today's fine spatial resolution capabilities to be met, huge data sets must be acquired, processed, and analyzed efficiently. In this paper, we present the results of an experimental parametric study exploring the limits of minimizing the amount of data required for tomographic reconstruction. We consider data acquisition system resolution and the effect of limited accuracy of stopping powers. We show graphically the specific results of variation of parameters affecting minimum data set size. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. RP SANDIA NATL LABS, LIVERMORE, CA 94551 USA. NR 23 TC 23 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X EI 1872-9584 J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 54 IS 1-3 BP 383 EP 389 DI 10.1016/0168-583X(91)95541-K PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FL821 UT WOS:A1991FL82100063 ER PT J AU SUSZCYNSKY, DM BOROVSKY, JE AF SUSZCYNSKY, DM BOROVSKY, JE TI SECONDARY-ELECTRON EMISSION FROM METALS IMPACTED BY HIGH-VELOCITY PARTICLES - MOLECULAR-EFFECT DEVIATIONS FROM A SINGLE-PARTICLE PICTURE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID ION BOMBARDMENT; TARGETS; SURFACES; ALUMINUM; HYDROGEN; YIELDS; GOLD; H-2+; H+ AB Experiments have been performed to study the influence of projectile molecular effects on the production of secondary electrons in the MeV/amu energy regime. Secondary-electron yields from Au, Ta and Al2O3 surfaces were measured using charged-particle projectiles provided by Van de Graaff accelerators (H+ at 1.5-6 MeV, H2+ at 2-6 MeV, H3+ at 3-6 MeV, He-3+ at 13-22 MeV, He-3(2+) at 13-33 MeV, He-4+ at 18-22 MeV, and He-4(2+) at 18-33 MeV) and scanning electron microscopes (electrons at 0.8-30 keV). For low projectile velocities, the total electron yield due to a composite projectile is less than the sum of the yields of the individual components of that projectile. This "molecular effect" is attributed to interference effects between the individual components of the projectile which lessen each component's ability to produce secondary electrons. As the projectile velocity is increased, these interference effects are reduced and the projectile as a whole becomes more effective in producing secondary electrons. Secondary electrons produced by backscattered electrons were also studied and found to constitute 60-80% of the total number of secondary electrons emitted from Au and Ta and approximately 40% of those emitted from Al2O3. These results are interpreted in terms of existing theories of secondary-electron emission. Ongoing computer simulations are contributing to an understanding of the particle dynamics of the secondary-electron emission process for composite projectiles and are showing qualitative agreement with experiment. RP SUSZCYNSKY, DM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SPACE PLASMA PHYS GRP,LOS ALAMOS,NM 87545, USA. NR 59 TC 9 Z9 9 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1991 VL 53 IS 3 BP 255 EP 266 DI 10.1016/0168-583X(91)95611-G PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FE939 UT WOS:A1991FE93900003 ER PT J AU MOSTELLER, RD EISENHART, LD LITTLE, RC EICH, WJ CHAO, J AF MOSTELLER, RD EISENHART, LD LITTLE, RC EICH, WJ CHAO, J TI BENCHMARK CALCULATIONS FOR THE DOPPLER COEFFICIENT OF REACTIVITY SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The Doppler coefficient of reactivity is a crucial parameter in the evaluation of several transients in light water reactors (LWRs). It is relatively small in magnitude and cannot be measured directly in operating reactors. Doppler coefficients are presented for slightly idealized pressurized water reactor pin cells. These coefficients were calculated with the MCNP-3A continuous-energy Monte Carlo code using data taken directly from the ENDF/B-V nuclear data library. This combination represents the most rigorous analytical tool and the best nuclear data available. Consequently, these results comprise a set of numerical benchmarks that may be used to evaluate the accuracy of LWR lattice physics codes in predicting Doppler behavior at operating conditions. An example of one such evaluation, using the CELL-2 code, is included. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. ELECT POWER RES INST,PALO ALTO,CA 94303. RP MOSTELLER, RD (reprint author), S LEVY INC,3425 S BASCOM AVE,CAMPBELL,CA 95008, USA. NR 11 TC 18 Z9 20 U1 1 U2 1 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 MAR PY 1991 VL 107 IS 3 BP 265 EP 271 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EZ675 UT WOS:A1991EZ67500006 ER PT J AU RYSKAMP, JM SELBY, DL PRIMM, RT AF RYSKAMP, JM SELBY, DL PRIMM, RT TI REACTOR DESIGN OF THE ADVANCED NEUTRON SOURCE SO NUCLEAR TECHNOLOGY LA English DT Article AB The ongoing preconceptual and conceptual reactor design of the Advanced Neutron Source (ANS) is explored. The ANS is being designed for materials sciences, isotope production, and fundamental physics research. A reactor design based on previously developed technology can meet the performance requirements set by the user community for a new ANS to serve all fields of neutron science. These requirements include the capability of producing a peak thermal neutron flux over five times higher than that in use at any currently operating steady-state facility. Achievement of these ultrahigh flux levels involves many interesting aspects of reactor design. The reactor characteristics of the current preconceptual reference design are presented. The attainment of this design was reached by following a design strategy that best met the safety and user requirements. The design has evolved over the last 5 yr from two concepts proposed in 1985. The trade-offs and selection of many reactor parameters are described to illustrate how and why the current design was achieved. Further reactor design is planned, leading to an ANS operating by 1999 for use by scientists of many disciplines. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP RYSKAMP, JM (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 47 TC 10 Z9 10 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 MAR PY 1991 VL 93 IS 3 BP 330 EP 349 PG 20 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EY925 UT WOS:A1991EY92500003 ER PT J AU CHU, KW DICKEY, FM AF CHU, KW DICKEY, FM TI OPTICAL COHERENCE MULTIPLEXING FOR INTERPROCESSOR COMMUNICATIONS SO OPTICAL ENGINEERING LA English DT Article DE COHERENCE MULTIPLEXING; MACH-ZEHNDER INTERFEROMETERS; OPTICAL COMMUNICATION; OPTICAL NOISE; PARALLEL COMPUTER ID SUPERLUMINESCENT DIODES; INTERFEROMETRIC SENSORS; FRINGE VISIBILITY; PHASE NOISE; INTERCONNECTIONS; SYSTEMS; TRANSMISSION; TECHNOLOGY; POWER; VLSI AB The development of an optical circuit that multiplexes gigabit-per-second electronic data streams into a very broad bandwidth (greater than 10 Gbit/s) optical signal would greatly enhance interprocessor communications in a parallel computer. One possibility that we are investigating is coherence multiplexing. In this method, time delays exceeding the coherence time of the light source are used to achieve multiplexing. We have analyzed the limitations of coherence multiplexing for high-speed data links. For the geometry we are investigating, the analysis shows that the signal decreases inversely as the square of the number of channels. Noise sources include photon shot noise, excess noise (classical optical field fluctuations), and detector noise. A suitable optical source must have a smooth, broad spectrum. Superluminescent diodes or edge-emitting diodes are the best candidates. We show how all of these factors affect the total information transfer rate. An integrated optical circuit for coherence multiplexing is being designed and built. This device is an array of four Mach-Zehnder interferometers integrated on a lithium niobate substrate. The differential delays will be achieved using proton exchange. Each interferometer will have two sets of electrodes, one for signal modulation and a second for fine adjustments of the delay. RP CHU, KW (reprint author), SANDIA NATL LABS,TECH STAFF,ALBUQUERQUE,NM 87185, USA. NR 30 TC 36 Z9 36 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1991 VL 30 IS 3 BP 337 EP 344 DI 10.1117/12.55803 PG 8 WC Optics SC Optics GA FA811 UT WOS:A1991FA81100015 ER PT J AU DOBRIANSKY, PJ RIVKIN, DB AF DOBRIANSKY, PJ RIVKIN, DB TI DOES THE SOVIET MILITARY OPPOSE PERESTROIKA SO ORBIS-A JOURNAL OF WORLD AFFAIRS LA English DT Article C1 US DEPT JUSTICE,OFF POLICY DEV,WASHINGTON,DC. US DOE,WASHINGTON,DC. RP DOBRIANSKY, PJ (reprint author), US INFORMAT AGCY,WASHINGTON,DC, USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU JAI PRESS INC PI GREENWICH PA 55 OLD POST RD-#2, PO BOX 1678, GREENWICH, CT 06836-1678 SN 0030-4387 J9 ORBIS-J WORLD AFF JI Orbis-J. World Aff. PD SPR PY 1991 VL 35 IS 2 BP 163 EP 178 PG 16 WC International Relations SC International Relations GA FJ633 UT WOS:A1991FJ63300001 ER PT J AU FISH, RH KIM, HS FONG, RH AF FISH, RH KIM, HS FONG, RH TI BONDING MODE OF NITROGEN HETEROCYCLIC LIGANDS TO (ETA-5-CYCLOPENTADIENYL)RUTHENIUM CATION AND REACTIVITY STUDIES OF THE NITROGEN AND PI-BONDED COMPLEXES - MECHANISTIC ASPECTS OF A NITROGEN TO PI REARRANGEMENT SO ORGANOMETALLICS LA English DT Article ID HOMOGENEOUS CATALYTIC-HYDROGENATION; ELECTRON-TRANSFER REACTIONS; SUBSTITUTION-REACTIONS; ARENE; RING; INTERMEDIATE; REDUCTION; SYSTEMS AB The nitrogen heterocyclic ligands pyridine (1), 2-methylpyridine (2), 2,4-dimethylpyridine (3), 2,4,6-trimethylpyridine (4), quinoline (5), isoquinoline (6), 2-methylquinoline (7), and 1,2,3,4-tetrahydroquinoline (8) were reacted with (eta-5-cyclopentadienyl)ruthenium cation, [CpRu(CH3CN)3](PF6), to ascertain the mode of bonding as a function of structure, i.e., nitrogen (eta-1(N)) versus pi (eta-6) bonding. Ligands 1-3, 5, and 6 formed N-bonded complexes, while 4, 7, and 8 only formed pi-bonded complexes. Thus, it appears that steric and electronic effects influence the bonding mode of nitrogen heterocyclic compounds to CpRu+. An interesting N (eta-1) to pi (eta-6) rearrangement occurred with the N-bonded CpRu+ complexes of ligands 2, 3, and 5, and mechanistic aspects were studied by H-1 NMR spectroscopy. Crossover experiments with [CpRu(eta-1(N)-2-methylpyridine)(CH3CN)2]+ (11) and [MeCpRu(eta-1(N)-2-methylpyridine-d7)(CH3CN)2]+ (21-d7) clearly show that N(eta-1)-bonded complexes undergo ligand exchange much faster than the N to pi rearrangement at 21-degrees-C (NMR probe temperature). Furthermore, neither N- and pi-bonded complexes nor pi- and pi-bonded complexes undergo ligand exchange with each other; however, both types of bonding modes did undergo facile exchange with free nitrogen ligand. These exchange reaction rates were found to be concentration-dependent. Consequently, our attempts to use the former result with N- and pi-bonded complexes to prove the intramolecular nature of the N to pi rearrangement, i.e., rearrangement of 11 in the presence of [MeCpRu(eta-6-2-methylpyridine-d7)]+ (22-d7), were not successful; exchange of any free 2 that might form, i.e., at low concentrations, with 22-d7 was found to be slower than the N to pi rearrangement. The role of the acetonitrile ligand in the N to pi rearrangement and in the displacement of eta-1- and eta-6-bonded nitrogen heterocyclic ligands will also be discussed. RP FISH, RH (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 28 TC 49 Z9 49 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD MAR PY 1991 VL 10 IS 3 BP 770 EP 777 DI 10.1021/om00049a043 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA FC015 UT WOS:A1991FC01500044 ER PT J AU LYLE, PA STRUVE, WS AF LYLE, PA STRUVE, WS TI DYNAMIC LINEAR DICHROISM IN CHROMOPROTEINS SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID BACTERIOCHLOROPHYLL-A-PROTEIN; FLUORESCENCE DEPOLARIZATION; PROSTHECOCHLORIS-AESTUARII; EXCITATION TRANSPORT; ROTATIONAL DIFFUSION; ENERGY-TRANSFER; ORIENTATION; GREEN; PIGMENTS; PROBE AB The time-dependent polarized fluorescence and optical density transients arising from electronic excitation transport are derived for solutions of randomly oriented chromoproteins in which the chromophore transition moments have well-defined orientations with respect to the protein. The treatment is extended to oriented monolayers of chromoproteins, in which the molecules are aligned with a particular protein-fixed axis perpendicular to the surface plane and with random azimuthal angles about the surface normal. The initial ratio of parallel to perpendicular transients is invariably 3 : 1, irrespective of system dimensionality and chromophore organization. The residual anisotropy observed at long times is directly related to the relative orientations of the donor and acceptor chromophores. These calculations form a basis for detailed interpretation of ultrafast fluorescence and pump-probe linear dichroism studies in photosynthetic systems, for which 3-dimensional structures are becoming increasingly available. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 20 TC 23 Z9 23 U1 0 U2 0 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD MAR PY 1991 VL 53 IS 3 BP 359 EP 365 DI 10.1111/j.1751-1097.1991.tb03641.x PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA EZ997 UT WOS:A1991EZ99700011 ER PT J AU PEAK, JG WOLOSCHAK, GE PEAK, MJ AF PEAK, JG WOLOSCHAK, GE PEAK, MJ TI ENHANCED EXPRESSION OF PROTEIN-KINASE-C GENE CAUSED BY SOLAR-RADIATION SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Note ID NEAR-ULTRAVIOLET RADIATIONS; SIGNAL TRANSDUCTION; TUMOR PROMOTION; MAMMALIAN-CELLS; FAR-ULTRAVIOLET; DNA DAMAGE; 3T3 CELLS; INDUCTION; DIACYLGLYCEROL; TRANSCRIPTION AB Natural solar radiation (5 min of midday exposure in mid July, latitude 42-degrees-N) induces protein kinase C mRNA almost two-fold in human epithelioid P3 cells in culture. This response is the same as that following tumor promotion by chemicals. The result indicates a possible role of promotion by solar UV radiation. C1 ARGONNE NATL LAB,DIV BIOL & MED RES,MOLEC PHOTOBIOL GRP,ARGONNE,IL 60439. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 FU PHS HHS [R01-34492, R01-37848] NR 28 TC 23 Z9 23 U1 0 U2 0 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD MAR PY 1991 VL 53 IS 3 BP 395 EP 397 DI 10.1111/j.1751-1097.1991.tb03646.x PG 3 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA EZ997 UT WOS:A1991EZ99700017 PM 2062882 ER PT J AU GAO, Y MERKLE, KL BAI, G CHANG, HLM LAM, DJ AF GAO, Y MERKLE, KL BAI, G CHANG, HLM LAM, DJ TI STRUCTURE AND COMPOSITION OF GRAIN-BOUNDARY DISLOCATION CORES AND STACKING-FAULTS IN MOCVD-GROWN YBA2CU3O7-X THIN-FILMS SO PHYSICA C LA English DT Article ID SUPERCONDUCTING YBA2CU3O7; ELECTRON-DIFFRACTION; ORIENTATION; AUGER AB The dislocation cores of a low-angle grain boundary in MOCVD-grown YBa2Cu3O7-x have been studied by high-resolution electron microscopy and image simulation. It was found that the low-angle boundary consists of a wall of discrete edge dislocations separated by relatively perfect lattice matching regions. Lattice reconstruction has been observed at the dislocation cores. The dislocation cores appear to be Cu-rich, with a core radius of about 1 nm. These observations are used to discuss the transition from strong to weak coupling behavior across grain boundaries. Stacking faults in the a-c and b-c planes have been observed for the first time in the MOCVD-grown YBa2Cu3O7-x thin films. HREM image analysis indicates that the stacking faults contain an extra Cu-O layer. The thickness of the stacking faults is about 1.6 (100) interplanar spacing, or 0.6 nm, which is smaller than the coherence length in a-b plane. Thus, the stacking faults are not expected to strongly affect superconducting properties. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. RP GAO, Y (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 23 TC 79 Z9 79 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAR 1 PY 1991 VL 174 IS 1-3 BP 1 EP 10 DI 10.1016/0921-4534(91)90413-S PG 10 WC Physics, Applied SC Physics GA FB825 UT WOS:A1991FB82500001 ER PT J AU DIXON, MA AF DIXON, MA TI THE NORMAL STATE ELECTRONIC-STRUCTURE OF CUPRATE SUPERCONDUCTORS - A COVALENT PICTURE SO PHYSICA C LA English DT Article ID HIGH-TC SUPERCONDUCTORS; BA-CU-O; SYSTEM; OXIDES; TEMPERATURE; COMPOUND; LA2CUO4 AB We propose a view of the cuprate superconductors based on strong covalent bonding within the CuO2 planes. This covalent picture was developed from an alternative analysis of some recently reported spectroscopic and transport properties of several high temperature superconductors. In this view, antiferromagnetic superexchange splits the sigma-x2-y2 orbital, and crystal field splitting leaves the pi-xy* orbital as the highest occupied molecular orbital (HOMO). In undoped materials, electrons in this orbital are localized, with a peak approximately 1.7 eV below the unoccupied half of the sigma-x2-y2* band. With doping, this orbital broadens into a band where the Fermi energy overlaps the energy of the lowest unoccupied state in the sigma-x2-y2 band. Further, the axial ligand found on all p-type cuprate superconductors raises the energy of the nearly-localized sigma-z2* orbital to an energy slightly below the top of the pi-xy* band. Excitations of electrons in these three bands yield the combination of properties found in the normal state of the cuprate materials. RP DIXON, MA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720, USA. NR 39 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAR 1 PY 1991 VL 174 IS 1-3 BP 117 EP 125 DI 10.1016/0921-4534(91)90427-Z PG 9 WC Physics, Applied SC Physics GA FB825 UT WOS:A1991FB82500015 ER PT J AU LINDEMER, TB WASHBURN, FA MACDOUGALL, CS CAVIN, OB AF LINDEMER, TB WASHBURN, FA MACDOUGALL, CS CAVIN, OB TI SYNTHESIS OF Y-BA-CU-O SUPERCONDUCTORS IN SUBATMOSPHERIC OXYGEN SO PHYSICA C LA English DT Article ID YBA2CU3O7-X; TEMPERATURES; ATMOSPHERE; INERT AB The YBa2Cu3O7-x and YBa2Cu4O8 phases were made from micron-size CuO, Y2O3, and BaCO3 by a process that included conversion at 50 to 1000 Pa O2 absolute. Thermogravimetric and X-ray analyses were used to characterize the conversion process. The process parameters included batch size, oxygen pressure, heating rate, final temperature, Y:Ba:Cu ratio, and CuO particle size. BaCuO2 was generally the only detectable intermediate phase. Friable powders with 150- to 600-ppm carbon were produced without the intermediate grinding and firing common to atmospheric processes. C1 OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP LINDEMER, TB (reprint author), OAK RIDGE NATL LAB,DIV CHEM TECHNOL,POB 2008,OAK RIDGE,TN 37831, USA. NR 34 TC 23 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAR 1 PY 1991 VL 174 IS 1-3 BP 135 EP 143 DI 10.1016/0921-4534(91)90429-3 PG 9 WC Physics, Applied SC Physics GA FB825 UT WOS:A1991FB82500017 ER PT J AU KWEI, GH SHI, JB KU, HC AF KWEI, GH SHI, JB KU, HC TI TL0.5PB0.5SR2CUO5 - A NONSUPERCONDUCTOR DESPITE AN OPTIMUM HOLE CONCENTRATION IN THE CU-O SHEETS SO PHYSICA C LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTOR; COPPER-OXIDE SUPERCONDUCTORS; CRYSTAL-STRUCTURE; BULK SUPERCONDUCTIVITY; NEUTRON POWDER; TL2BA2CACU2O8; SINGLE; TC; DIFFRACTION; SYSTEMS AB Doping of La3+ for Ba2+ in TlBa2CuO5 leads to superconductivity in the material TlBa1.2La0.8CuO5 (with T(c) almost-equal-to 52 K). An increase in the Cu-O in-plane bond distance [1.9240 (1) angstrom] from that in TlBa2CuO5 (1.915 angstrom) is consistent with a lowering of the average hole concentration, p, in the Cu-O planes from 1.0 to approximately +0.4. We have doped Pb4+ for Tl3+ in TlSr2CuO5 to give an average hole concentration of +0.53, but find that Tl0.5Pb0.5Sr2CuO5 is not superconducting down to 5 K. The structure is similar to TlBa2CuO5 and TlSr2CuO5, belonging to the space group P4/mmm. Structural refinement using neutron powder diffraction data collected at 300 K show that the planar lattice constant [a = 3.7309 (3) angstrom] is considerably smaller than that for TlBa1.2La0.8CuO5. This leads to the substantially smaller Cu-O in-plane bond distance of 1.8654 (15) angstrom. The atoms in the Tl/Pb-O(3) planes are again disordered, and both the cation and the oxygen site occupancies are close to stoichiometry. This stoichiometry and the Tl/Pb oxidation states suggest that the hole concentration is close to the optimum value for these materials. Several reasons for the absence of superconductivity are discussed. C1 NATL TSING HUA UNIV,DEPT PHYS,HSINCHU 30043,TAIWAN. RP KWEI, GH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 34 TC 31 Z9 31 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 MAR 1 PY 1991 VL 174 IS 1-3 BP 180 EP 186 DI 10.1016/0921-4534(91)90434-Z PG 7 WC Physics, Applied SC Physics GA FB825 UT WOS:A1991FB82500022 ER PT J AU SAKURAI, T YAMASHITA, T WILLIS, JO YAMAUCHI, H TANAKA, S KWEI, GH AF SAKURAI, T YAMASHITA, T WILLIS, JO YAMAUCHI, H TANAKA, S KWEI, GH TI COMBINED X-RAY AND NEUTRON POWDER DIFFRACTION STUDY OF THE STRUCTURE OF LA1.8SR0.2CACU2O6 - CATION ORDERING AND OXYGEN STOICHIOMETRY SO PHYSICA C LA English DT Article ID SUPERCONDUCTIVITY; REFINEMENT; OXIDES; PHASE AB La1.8Sr0.2CaCu2O6 exhibits superconductivity around T(c) = 60 K after a HIP (Hot Isostatic Pressing) treatment at 1020-degrees-C for 50 h under a total pressure of 1000 atm and an oxygen partial pressure of 200 atm. A joint neutron/X-ray powder diffraction study of this superconductor was carried out to analyze both cation ordering and oxygen stoichiometry. This revealed: (1) a preferential occupation of Ca for the 2a site and of both La and Sr for the 4e site, (2) a Cu-O(1) bond length which is the shortest among known 326 cuprates, and (3) that the O(2) site contains approximately 3.5% vacancies and the O(3) site is occupied at a level of approximately 2.3%. A comparison of the structure of La1.8Sr0.2CaCu2O6 with those of four nonsuperconducting or weakly superconducting doped 326 cuprates suggests structural differences that may be responsible for the observed differences in behavior. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR EXPLORATORY RES & DEV,LOS ALAMOS,NM 87545. RP SAKURAI, T (reprint author), INT SUPERCONDUCT TECHNOL CTR,SUPERCONDUCT RES LAB,10-13 SHINONOME 1 CHOME,KOTO KU,TOKYO 135,JAPAN. RI Yamashita, Toru/A-9818-2012 NR 28 TC 31 Z9 31 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAR 1 PY 1991 VL 174 IS 1-3 BP 187 EP 194 DI 10.1016/0921-4534(91)90435-2 PG 8 WC Physics, Applied SC Physics GA FB825 UT WOS:A1991FB82500023 ER PT J AU THEILER, J MAYERKRESS, G KADTKE, JB AF THEILER, J MAYERKRESS, G KADTKE, JB TI CHAOTIC ATTRACTORS OF A LOCALLY CONSERVATIVE HYPERBOLIC MAP WITH OVERLAP SO PHYSICA D LA English DT Article ID ITERATED FUNCTION SYSTEMS; FAT FRACTALS; CONSTRUCTION; DIMENSION AB We introduce a class of hyperbolic maps which are locally conservative but globally dissipative. The dissipation stems not from local contraction of phase space but from the overlap that arises from the noninvertibility of the map. The dynamics of these maps are chaotic, and the attractors are strange, although not necessarily fractal. Though several examples of this class are provided, our analysis concentrates on a single example which is obtained as a modification of the baker's transform. We discuss the morphology of the attractors as the map parameter is varied. We find that some attractors are "thin" fractals and others are "fat" sets of positive measure. We are able to characterize the parameter values that lead to these two kinds of attractors, and for certain parameter values, we can derive analytically exact values for the fractal dimension or for the fat fractal scaling exponent. Taken together, these results lead us to conjecture that the generic attractor of this map has zero measure and full dimension. C1 UNIV CALIF SAN DIEGO,INST NONLINEAR SCI,LA JOLLA,CA 92093. MIT,LINCOLN LAB,LEXINGTON,MA 02173. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. SANTA FE INST,SANTA FE,NM 87501. NR 26 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD MAR PY 1991 VL 48 IS 2-3 BP 425 EP 444 DI 10.1016/0167-2789(91)90096-R PG 20 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA FH623 UT WOS:A1991FH62300010 ER PT J AU COWAN, RD WILSON, M AF COWAN, RD WILSON, M TI SIMPLE ESTIMATES OF ATOMIC NEGATIVE-ION STRUCTURES SO PHYSICA SCRIPTA LA English DT Article ID ENERGY; STATES; SCATTERING; BERYLLIUM AB Ab initio calculation of electron affinities and level structures have been obtained by adding a simple approximate correlation-potential term to the usual pseudo-relativistic Hartree-Fock Hamiltonian. Results for the following systems the 2s2p2 and 2p3 configurations of Be-, the p3 configurations of C-, Si-, Ge-, Sn- and Pb-, the s2p and sp2 configurations of Mg-, Ca-, Sr-, Ba- and Ra-, and the s2p and sp2 configurations of Zn-, Cd- and Hg- are reported here and compared, when possible, with earlier theoretical and experimental results. C1 UNIV LONDON,ROYAL HOLLOWAY & BEDFORD NEW COLL,DEPT PHYS,EGHAM TW20 0EX,SURREY,ENGLAND. RP COWAN, RD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 19 TC 39 Z9 39 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD MAR PY 1991 VL 43 IS 3 BP 244 EP 247 DI 10.1088/0031-8949/43/3/005 PG 4 WC Physics, Multidisciplinary SC Physics GA FC401 UT WOS:A1991FC40100005 ER PT J AU WHITFIELD, SB CALDWELL, CD KRAUSE, MO AF WHITFIELD, SB CALDWELL, CD KRAUSE, MO TI ENHANCEMENT OF EXCITED-STATE POPULATION OF MAGNESIUM-IONS UPON DECAY OF AUTOIONIZING RESONANCES SO PHYSICAL REVIEW A LA English DT Article ID SYNCHROTRON RADIATION; SELECTIVE EXCITATION; ATOMIC MAGNESIUM; AUGER DECAY; PHOTOIONIZATION; IONIZATION; SPECTRUM; BARIUM; VAPOR; SR AB Decay of autoionizing resonances in atoms often leads to preferential production of excited states of the resulting ion. The population of these states can exceed the population of the ground state by more than an order of magnitude. We report measurements of the branching ratios for Mg+ ions resulting from the decay of selected autoionizing levels. These derived either from single excitation of a 2p electron or from two-electron excitations. For excited states of the type 2p5(2P1/2,3/2)3s2ns, n = 4 or 5, production of Mg+ ions having the final configuration 2p6ns is the predominant decay feature. For n > 5, the predominant decay feature is the 2p6(n + 1)s configuration, indicating that shakeup is very strong in the decay of the excited state. For excited states of the type 2p5(2P1/2)5d and 2p5(2P3/2)6d, the decay behaves in a manner similar to that of the ns states. However, for the 2p5(2P1/2)6d state, the most prominent decay channel appears to be the 2p611d state, which leads to the emission of an electron with the same kinetic energy as the L2-M1M1 Auger line. C1 OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP WHITFIELD, SB (reprint author), UNIV CENT FLORIDA,DEPT PHYS,ORLANDO,FL 32816, USA. NR 27 TC 32 Z9 32 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR 1 PY 1991 VL 43 IS 5 BP 2338 EP 2352 DI 10.1103/PhysRevA.43.2338 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200025 ER PT J AU LINDLE, DW COWAN, PL JACH, T LAVILLA, RE DESLATTES, RD PERERA, RCC AF LINDLE, DW COWAN, PL JACH, T LAVILLA, RE DESLATTES, RD PERERA, RCC TI POLARIZED X-RAY-EMISSION STUDIES OF METHYL-CHLORIDE AND THE CHLOROFLUOROMETHANES SO PHYSICAL REVIEW A LA English DT Article ID SYNCHROTRON RADIATION BEAMLINE; VALENCE ELECTRON-SPECTRA; INNER-SHELL EXCITATION; HIGH-ENERGY-RESOLUTION; PHOTOELECTRON-SPECTRA; ABSORPTION-SPECTRA; SUBSTITUTED METHANES; VACUUM ULTRAVIOLET; ORGANIC-MOLECULES; SPECTROSCOPY AB A new technique sensitive to molecular orientation and geometry, and based on measuring the polarization of x-ray emission, has been applied to the Cl-containing molecules methyl chloride (CH3Cl) and the chlorofluoromethanes (CF3Cl, CF2Cl2, and CFCl3) in the gas phase. Upon selective excitation using monochromatic synchrotron radiation in the Cl K-edge (Cl ls) near-threshold region, polarization-selective x-ray emission studies reveal highly polarized molecular valence x-ray fluorescence for all four molecules. The degree and the orientation of the polarized emission are observed to be sensitive to the incident excitation energy near the Cl K edge. In some cases, the polarization direction for x-ray emission reverses for small changes in incident excitation energy (a few eV). It is shown that the polarized x-ray emission technique can be used to infer, directly from experiment, symmetries of occupied and unoccupied valence molecular orbitals, anisotropies in absorption and emission, and orientational and geometrical information. It is suggested that the x-ray polarized-fluorescence phenomenon, reported here for simple molecules, can be used as a new approach to study more complicated systems in a variety of environments. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV ACCELERATOR & FUS RES,ADV LIGHT SOURCE,BERKELEY,CA 94720. RP LINDLE, DW (reprint author), NIST,GAITHERSBURG,MD 20899, USA. NR 69 TC 37 Z9 37 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR 1 PY 1991 VL 43 IS 5 BP 2353 EP 2366 DI 10.1103/PhysRevA.43.2353 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200026 ER PT J AU PIESTRUP, MA MORAN, MJ BOYERS, DG PINCUS, CI KEPHART, JO GEARHART, RA MARUYAMA, XK AF PIESTRUP, MA MORAN, MJ BOYERS, DG PINCUS, CI KEPHART, JO GEARHART, RA MARUYAMA, XK TI GENERATION OF HARD X-RAYS FROM TRANSITION RADIATION USING HIGH-DENSITY FOILS AND MODERATE-ENERGY ELECTRONS SO PHYSICAL REVIEW A LA English DT Article ID PERIODIC RADIATORS AB In experiments using targets consisting of many thin metal foils, we have demonstrated that a narrow, forward-directed cone of transition radiation in the 8- to 60-ke V spectral range can be generated by electron beams with moderate energies (between 100 and 500 MeV). The theory suggests that high-density, moderate-atomic-number metals are the optimum foil materials and that the foil thickness can be chosen to maximize photon production within a desired spectral range. The three targets used in the experiments consisted of 10 foils of 1-mu-m-thick gold, 40 foils of 8.5-mu-m stainless steel, and 20 foils of 7.9-mu-m copper. The efficiency with which hard x rays are generated, and the fact that the requisite electron-beam energies are lower by a factor of 5 to 10, make such a radiation source an attractive alternative to synchrotron radiation for applications such as medical imaging, spectroscopy, and microscopy. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. USN,POSTGRAD SCH,MONTEREY,CA 93943. RP PIESTRUP, MA (reprint author), ADELPHI TECHNOL INC,285 HAMILTON AVE,SUITE 430,PALO ALTO,CA 94301, USA. NR 25 TC 13 Z9 14 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 MAR 1 PY 1991 VL 43 IS 5 BP 2387 EP 2396 DI 10.1103/PhysRevA.43.2387 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200029 ER PT J AU DEUTSCH, IH GARRISON, JC AF DEUTSCH, IH GARRISON, JC TI PARAXIAL QUANTUM PROPAGATION SO PHYSICAL REVIEW A LA English DT Article ID SUPERFLUORESCENCE; AMPLIFIER AB A quantum version of the classical paraxial approximation is established. After expanding the classical free-field wave equation in powers of theta (the characteristic opening angle of the paraxial rays), the familiar time-dependent paraxial equation appears in zeroth order. The arguments employed in deriving this approximation scheme are used in turn to identify the subspace of the photon Fock space consisting of paraxial states of the field. The quantum version of the paraxial approximation is then obtained by restricting the Maxwell field operators to this domain. Exact equal-time commutation relations are recovered as expansions in theta. In zeroth order, the theory yields a quantized analog of the classical paraxial wave equation, and formally resembles a nonrelativistic many-body theory. This formalism is applied to show that Mandel's local-photon-number operator and Glauber's photon-counting operator reduce, in zeroth order, to the same true-number operator. In addition, it is shown that the O (theta-2) difference between them vanishes for experiments described by stationary coherent states. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. RI Deutsch, Ivan/D-1882-2009 OI Deutsch, Ivan/0000-0002-1733-5750 NR 35 TC 52 Z9 52 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD MAR 1 PY 1991 VL 43 IS 5 BP 2498 EP 2513 DI 10.1103/PhysRevA.43.2498 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200041 ER PT J AU CHI, HC HUANG, KN CHENG, KT AF CHI, HC HUANG, KN CHENG, KT TI AUTOIONIZING LEVELS OF BERYLLIUM FROM THE MULTICONFIGURATION RELATIVISTIC RANDOM-PHASE APPROXIMATION SO PHYSICAL REVIEW A LA English DT Note ID QUANTUM-DEFECT THEORY; DOUBLY EXCITED-STATES; PHOTO-IONIZATION; SPIN POLARIZATION; CROSS-SECTION; OUTER SHELLS; MG-I; PHOTOIONIZATION; MAGNESIUM; RESONANCES AB Autoionizing levels of beryllium near its first ionization threshold are investigated using the multiconfiguration relativistic random-phase approximation. The 2pns 1P1-degrees and 2pnd 1P1-degrees Rydberg series of doubly excited states manifest as autoionization resonances in the 2s photoionization cross section. Theoretical predictions and available experimental data are in excellent agreement within 0.05 eV. C1 NATL TAIWAN UNIV,DEPT PHYS,TAIPEI 10764,TAIWAN. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP CHI, HC (reprint author), ACAD SINICA,INST ATOM & MOLEC SCI,POB 23-166,TAIPEI 10764,TAIWAN. RI Huang, Keh-Ning/F-7927-2012 NR 52 TC 36 Z9 36 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 MAR 1 PY 1991 VL 43 IS 5 BP 2542 EP 2545 DI 10.1103/PhysRevA.43.2542 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200048 ER PT J AU SUSSKIND, SM VALEO, EJ OBERMAN, CR BERNSTEIN, IB AF SUSSKIND, SM VALEO, EJ OBERMAN, CR BERNSTEIN, IB TI CHARGE STATES OF MANY-ELECTRON ATOMS IN A STRONG LASER FIELD SO PHYSICAL REVIEW A LA English DT Note ID ABOVE-THRESHOLD IONIZATION; MULTIPHOTON IONIZATION; NOBLE-GASES AB The nonresonant, multiphoton ionization of many-electron atoms is explained theoretically within the Thomas-Fermi model with the inclusion of an electromagnetic field. Numerical results are presented for the charge state and induced dipole moment versus the strength of the applied electric field, which, because of the scaling properties of the model, can be expressed as universal functions of the field. Our results compare favorably with those from recent ionization experiments performed on noble gases using laser fields. C1 YALE UNIV,APPL PHYS SECT,NEW HAVEN,CT 06520. RP SUSSKIND, SM (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 14 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR 1 PY 1991 VL 43 IS 5 BP 2569 EP 2572 DI 10.1103/PhysRevA.43.2569 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EZ702 UT WOS:A1991EZ70200055 ER PT J AU GONZALEZ, R CHEN, Y SEBEK, RM WILLIAMS, GP WILLIAMS, RT GELLERMANN, W AF GONZALEZ, R CHEN, Y SEBEK, RM WILLIAMS, GP WILLIAMS, RT GELLERMANN, W TI PROPERTIES OF THE 800-NM LUMINESCENCE BAND IN NEUTRON-IRRADIATED MAGNESIUM-OXIDE CRYSTALS SO PHYSICAL REVIEW B LA English DT Article ID LI-DOPED MGO AB We present results on the luminescence at 800 nm which occurs upon excitation of the 573-nm optical absorption band attributed to an aggregate defect in neutron-irradiated MgO crystals both pure and doped. The study was undertaken to evaluate the suitability of this luminescence for a tunable laser. Absorption, luminescence, and excitation spectra were measured before and after isochronal annealing, with the goal of optimizing the luminescence intensity and stability of the responsible defect, and reducing the background absorption in the crystal. The emission intensity is highest after annealing at approximately 550 K independent of dose. A thermally induced absorption band at 565 nm, which emerges at approximately 550 K, does not contribute to the emission at 800 nm. Under low-intensity continuous excitation, the 573-nm absorption band is not susceptible to photoconversion. However, when pumped with high-intensity laser light, the band exhibits a decay which recovers within 0.5 s. The luminescence has a single-exponential decay time of 15.5 ns at room temperature, and the band shape remains essentially constant throughout the decay. Tests for laser action using pulsed and cw pump lasers were unsuccessful at 77 and 300 K. C1 WAKE FOREST UNIV,DEPT PHYS,WINSTON SALEM,NC 27109. UNIV UTAH,DEPT PHYS,SALT LAKE CITY,UT 84101. UNIV COMPLUTENSE MADRID,FAC CIENCIAS FIS,DEPT FIS ESTADO SOLIDO,E-28040 MADRID,SPAIN. RP GONZALEZ, R (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 16 TC 15 Z9 16 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 MAR 1 PY 1991 VL 43 IS 7 BP 5228 EP 5233 DI 10.1103/PhysRevB.43.5228 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200003 ER PT J AU SABOCHICK, MJ LAM, NQ AF SABOCHICK, MJ LAM, NQ TI RADIATION-INDUCED AMORPHIZATION OF ORDERED INTERMETALLIC COMPOUNDS CUTI, CUTI2, AND CU4TI3 - A MOLECULAR-DYNAMICS STUDY SO PHYSICAL REVIEW B LA English DT Article ID IRRADIATION-INDUCED AMORPHIZATION; EMBEDDED-ATOM METHOD; AMORPHOUS TRANSITION; ELECTRON-IRRADIATION; ATOMISTIC SIMULATION; DEFECT RECOVERY; CRYSTALLINE; METALS; DEPENDENCE; DISORDER AB Solid-state amorphization resulting from the introduction of chemical disorder and point defects in the ordered intermetallic compounds CuTi, CuTi2, and Cu4Ti3 was investigated, with use of the isobaric-isothermal molecular-dynamics method in conjunction with embedded-atom potentials. Antisite defects were produced by randomly exchanging Cu and Ti atoms, and vacancies and interstitials were created by removing atoms at random from their normal sites and inserting atoms at random positions in the lattice, respectively. The potential energy, volume expansion, and pair-correlation function were calculated as functions of the numbers of atoms exchanges and point defects. The results indicated that, although both chemical disordering and point-defect introduction increased the system energy and volume, the presence of point defects was essential to trigger the crystalline-to-amorphous transition. By comparing the pair-correlation function calculated after the introduction of point defects with that of the quenched liquid alloy, the critical damage dose (in dpa, displacements per atom) for amorphization was estimated for each compound: approximately 0.7 dpa for CuTi, approximately 0.5 dpa for CuTi2, and approximately 0.6 dpa for Cu4Ti3. At the onset of amorphization, the volume expansions were found to be approximately 1.9%, approximately 3.7%, and approximately 1.7% for these respective compounds. In general, the results obtained in the present work are in good agreement with experimental observations. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP SABOCHICK, MJ (reprint author), USAF,INST TECHNOL,DEPT ENGN PHYS,WRIGHT PATTERSON AFB,OH 45433, USA. NR 44 TC 94 Z9 94 U1 0 U2 16 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 MAR 1 PY 1991 VL 43 IS 7 BP 5243 EP 5252 DI 10.1103/PhysRevB.43.5243 PN A PG 10 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200005 ER PT J AU BARBEE, TW COHEN, ML AF BARBEE, TW COHEN, ML TI PREDICTION OF HIGH-TEMPERATURE SUPERCONDUCTIVITY IN HEXAGONAL AND RHOMBOHEDRAL PHASES OF METALLIC HYDROGEN SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-PHONON INTERACTION AB Under extreme pressure, hydrogen is predicted to transform from a low-pressure molecular solid into an atomic solid. Several candidate structures for the atomic solid are studied as candidates for superconductivity. In particular, the 9R (alpha-Sm) structure is found to be stable with a predicted transition temperature T(c) = 140-170 K. Results for hexagonal phases are also discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP BARBEE, TW (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 20 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 MAR 1 PY 1991 VL 43 IS 7 BP 5269 EP 5275 DI 10.1103/PhysRevB.43.5269 PN A PG 7 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200008 ER PT J AU ZHANG, JG BI, XX MCRAE, E EKLUND, PC SALES, BC MOSTOLLER, M AF ZHANG, JG BI, XX MCRAE, E EKLUND, PC SALES, BC MOSTOLLER, M TI OPTICAL STUDIES OF SINGLE-CRYSTAL ND2-XCEXCUO4-DELTA SO PHYSICAL REVIEW B LA English DT Article ID THIN-FILMS; CE; SUPERCONDUCTIVITY; TRANSPORT; CARRIERS; OXIDES AB Optical reflectivity spectra of Nd2CuO4-delta and Nd1(.8)Ce0(.2)CuO4-delta single crystals for the polarization E parpendicular-to c have been investigated over an energy range from 0.005 to 6 eV. Four E(u) intralayer phonons are observed for Nd2CuO4-delta at 121, 301, 347, and 507 cm-1, in good agreement with preliminary shell-model-calculation results. The oscillator strength of a broad mid-ir bands is found to depend on both oxygen deficiency and cerium doping. The far-ir optical conductivity is fit to both the recently proposed marginal-Fermi-liquid model (MFL) and the modified Drude-Lorentz model (MDL). A notch in the far-ir conductivity is observed at 24 meV, in good agreement with the MFL model. Values for the plasma frequency obtained are quite low and suggest that very large mass enhancement exists for the free carriers in these materials. A clear downshift of oscillator strength from (1-2.3)-eV charge-transfer excitation to the mid-ir band is also observed. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV NANCY 1,FAC SCI,CHIM MINERALE APPL LAB,F-54506 VANDOEUVRE NANCY,FRANCE. RP ZHANG, JG (reprint author), UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506, USA. NR 25 TC 31 Z9 31 U1 0 U2 5 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 MAR 1 PY 1991 VL 43 IS 7 BP 5389 EP 5396 DI 10.1103/PhysRevB.43.5389 PN A PG 8 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200024 ER PT J AU KIVSHAR, YS CHUBYKALO, OA AF KIVSHAR, YS CHUBYKALO, OA TI JOSEPHSON-JUNCTION DYNAMICS IN THE PRESENCE OF A LOCALIZED MAGNETIC INHOMOGENEITY SO PHYSICAL REVIEW B LA English DT Article ID SOLITONS; VORTICES; FLUXON AB Fluxon scattering by a local magnetic inhomogeneity is studied analytically in the framework of the perturbation theory for solitions. Threshold values of the bias-current density admitting the escape and trapping of a fluxon by the impurity are calculated. The energy of the plasma (Svihart) waves radiated by the scattering fluxon is taken into account to analyze the current-voltage (I-V) characteristic of the inhomogeneous junction. It is demonstrated that the I-V characteristic depends on the fluxon polarity, and the change of the polarity may lead to the appearance of a step on the I-V characteristic. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. INST LOW TEMP PHYS & ENGN,KHARKOV 310164,USSR. UNIV OXFORD,CLARENDON LAB,OXFORD,ENGLAND. NR 23 TC 10 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 5419 EP 5424 DI 10.1103/PhysRevB.43.5419 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200026 ER PT J AU ROUTBORT, JL ROTHMAN, SJ CHEN, N MUNDY, JN BAKER, JE AF ROUTBORT, JL ROTHMAN, SJ CHEN, N MUNDY, JN BAKER, JE TI SITE SELECTIVITY AND CATION DIFFUSION IN YBA2CU3O7-DELTA SO PHYSICAL REVIEW B LA English DT Article ID OXYGEN AB Tracer diffusion of Co, Zn, and Cu has been studied in polycrystals of YBa2Cu3O7-delta from 600 to 950-degrees-C at an oxygen partial pressure of 1 atm using serial sectioning or the secondary-ion mass spectrometry technique. The present and previously published values of the diffusion coefficient of Cu fall on the same Arrhenius line. The diffusion coefficients of Zn and Cu and published values for Ni are close to each other and the activation energies are almost the same. Measurements of diffusion of Co and Ni in single-crystal c-axis platelets indicate a much greater diffusional anisotropy for Co than for Ni. Diffusion coefficients of Cu are less than published diffusion coefficients of Ag, possibly because Ag attracts oxygen-ion vacancies. The interaction between cations and oxygen vacancies can explain the increase in the diffusion of Cu with decreasing P(O2) at 850-degrees-C. C1 UNIV ILLINOIS, CTR MICROANAL MAT, URBANA, IL 61801 USA. RP ROUTBORT, JL (reprint author), ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 20 TC 53 Z9 53 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 5489 EP 5497 DI 10.1103/PhysRevB.43.5489 PN A PG 9 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200036 ER PT J AU SALEMSUGUI, S ALP, EE MINI, SM RAMANATHAN, M CAMPUZANO, JC JENNINGS, G FAIZ, M PEI, S DABROWSKI, B ZHENG, Y RICHARDS, DR HINKS, DG AF SALEMSUGUI, S ALP, EE MINI, SM RAMANATHAN, M CAMPUZANO, JC JENNINGS, G FAIZ, M PEI, S DABROWSKI, B ZHENG, Y RICHARDS, DR HINKS, DG TI DETERMINATION OF THE LOCAL-STRUCTURE IN BA1-XKXBIO3 BY X-RAY-ABSORPTION SPECTROSCOPY SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTIVITY; BA2BI3+BI5+O6; TEMPERATURE; SYSTEM AB The local structure around Bi atoms has been studied in Ba(1-x)K(x)BiO3 (0.0 < x < 0.4) via x-ray-absorption spectroscopy. The structure is determined in terms of coordination numbers and interatomic distances around the Bi atoms between 300 and 13 K from Bi L3 extended x-ray-absorption fine-structure data. The charges on Bi and O have been measured as a function of K doping using Bi L3, and O K-edge x-ray-absorption near-edge-structure spectroscopy. It was found that the ordered breathing-mode-type distortion in BaBiO3 is replaced by a disordered distortion of the same type when K is substituted into the Ba site, which persists down to 13 K for x = 0.2 and disappears for the x = 0.4 composition. The overall Bi valence increases only slightly whereas O 2p orbitals are doped with holes with increasing K content. As the insulator-metal boundary is crossed for x = 0.35 these holes become delocalized, and contribute to the metallic behavior of the Ba0.6K0.4BiO3 compound. C1 UNIV ILLINOIS,CHICAGO,IL 60680. RP SALEMSUGUI, S (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Campuzano, Juan Carlos/G-4358-2012 NR 18 TC 67 Z9 70 U1 0 U2 12 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 MAR 1 PY 1991 VL 43 IS 7 BP 5511 EP 5515 DI 10.1103/PhysRevB.43.5511 PN A PG 5 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200038 ER PT J AU XU, YW SUENAGA, M AF XU, YW SUENAGA, M TI IRREVERSIBILITY TEMPERATURES IN SUPERCONDUCTING OXIDES - THE FLUX-LINE-LATTICE MELTING, THE GLASS-LIQUID TRANSITION, OR THE DEPINNING TEMPERATURES SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; BA-CU-O; SMALL DRIVING FORCES; CRITICAL CURRENTS; CRYSTAL; CREEP; DEPENDENCE; YBA2CU3O7; FILMS; FLOW AB The magnetic-field dependence of the irreversibility temperatures follows an H = a[1-T(r)(H)/T(c)(0)]n relationship with n approximately-equal-to 1.5, for pure and alloyed YBa2(Cu(1-x)M(x))3O7+delta with x = 0 and 0.02, where M = Al, Fe, Ni, and Zn, measured for an applied field parallel to the c axis. However, for M = Ni and x = 0.04 and 0.06, n approximately-equal-to 2.0. This relationship is not applicable for either Bi2Sr2CaCu2O8 or (Bi,Pb)2Sr2Ca2Cu3O10 powders. It is also shown that the irreversibility temperature is a strong function of the magnetic hysteresis width DELTA-M for pure and alloyed YBa2Cu3O7. These results and the measurements of the flux creep DELTA-M(t) for these specimens suggest that T(r)(H) is a depinning line rather than a lattice melting or glass-to-liquid phase-transition temperature. However, the conventional flux-creep model cannot account for all of the observed temporal dependences of DELTA-M(t). RP XU, YW (reprint author), BROOKHAVEN NATL LAB,DIV MAT SCI,UPTON,NY 11973, USA. NR 53 TC 110 Z9 111 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 MAR 1 PY 1991 VL 43 IS 7 BP 5516 EP 5525 DI 10.1103/PhysRevB.43.5516 PN A PG 10 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200039 ER PT J AU CHOU, H TRANQUADA, JM SHIRANE, G MASON, TE BUYERS, WJL SHAMOTO, S SATO, M AF CHOU, H TRANQUADA, JM SHIRANE, G MASON, TE BUYERS, WJL SHAMOTO, S SATO, M TI NEUTRON-SCATTERING STUDY OF SPIN FLUCTUATIONS IN SUPERCONDUCTING YBA2CU3O6+0.40, YBA2CU3O6+0.45, YBA2CU3O6+0.50 SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC PHASE-DIAGRAM; HEISENBERG-ANTIFERROMAGNET; LOW-TEMPERATURES; DOPED LA2CUO4; EXCITATIONS; TC; LA1.85SR0.15CUO4; BEHAVIOR; DYNAMICS AB We show by inelastic neutron scattering that dynamic spin correlations coexist with superconductivity in YBa2Cu3O6+x (x = 0.4,0.45,0.5). For the x = 0.5, T(c) = 50 K sample, the inelastic magnetic intensity at DELTA-E = 6 meV does not show any change near T(c) and is approximately constant from 250 to 10 K, in contrast to earlier data on superconducting La1.85Sr0.15CuO4 (T(c) = 35 K) which showed a decrease of the integrated intensity at a temperature well above T(c). The inelastic magnetic cross section observed here can be consistently modeled as two-dimensional spin waves overdamped by short correlation lengths. The correlation length in the x = 0.5 sample is an order of magnitude smaller than in the x = 0.40 and x = 0.45 samples, indicating a drastic disruption of planar copper spin-spin correlation upon hole doping. The present results are compared with recent NMR studies of T(c) = 60 K material. C1 MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4M1,ONTARIO,CANADA. ATOM ENERGY CANADA LTD,RES,CHALK RIVER K0J 1J0,ONTARIO,CANADA. NAGOYA UNIV,FAC SCI,DEPT PHYS,CHIKUSA KU,NAGOYA 46401,JAPAN. RP CHOU, H (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. RI Tranquada, John/A-9832-2009; Mason, Thomas/M-5809-2014 OI Tranquada, John/0000-0003-4984-8857; Mason, Thomas/0000-0003-1880-3971 NR 35 TC 59 Z9 59 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 5554 EP 5563 DI 10.1103/PhysRevB.43.5554 PN A PG 10 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200042 ER PT J AU ERIKSSON, O ALBERS, RC BORING, AM AF ERIKSSON, O ALBERS, RC BORING, AM TI CALCULATED MAGNETIC-PROPERTIES OF THE ANTIFERROMAGNETIC UNISN COMPOUND SO PHYSICAL REVIEW B LA English DT Article ID TERNARY U-COMPOUNDS AB The electronic structure, magnetic moment, and magnetic form factor of the type-I antiferromagnet UNiSn has been calculated. The calculations include spin-polarization and are fully relativistic, with the spin-orbit interaction included at the variational step. It is found that including relativistic and orbital-polarization terms is important. With these interactions included, fair agreement between theory and experiment is found concerning the sublattice moments as well as the magnetic form factor. The sublattice moment is found to be composed of a large spin and orbital part that are coupled antiparallel with the orbital moment dominating. The present results show that the previous agreement between the spin-only moment and experiment was only fortuitous and indicates the complexity of magnetism in actinide systems. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP ERIKSSON, O (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 29 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 5649 EP 5652 DI 10.1103/PhysRevB.43.5649 PN A PG 4 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200053 ER PT J AU GIBBS, D GRUBEL, G HARSHMAN, DR ISAACS, ED MCWHAN, DB MILLS, D VETTIER, C AF GIBBS, D GRUBEL, G HARSHMAN, DR ISAACS, ED MCWHAN, DB MILLS, D VETTIER, C TI POLARIZATION AND RESONANCE STUDIES OF X-RAY MAGNETIC SCATTERING IN HOLMIUM SO PHYSICAL REVIEW B LA English DT Article ID RARE-EARTH-METALS; EXCHANGE SCATTERING; DIFFRACTION; TRANSITIONS; GD AB We report the results of an x-ray-scattering study of the polarization and resonance properties of the magnetic cross section of holmium. Off resonance, we have measured the degree of linear polarization for several different chemical and magnetic reflections, and shown that the results are consistent with a nonresonant description of the x-ray-scattering cross section. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering, and resonant integer harmonics, are observed. Detailed measurements of the dependence of the integrated magnetic intensity on the incident x-ray energy, on the x-ray momentum transfer, and on the sample temperature are described for incident x-ray energies in a range of 250 eV below and above the L(III) absorption edge. In addition, we have characterized the energy dependence of the linearly sigma- and pi-polarized components of the magnetic scattering in this range, and fitted the resulting line shapes to a simple model of the resonant cross section, including electric dipole and quadrupole transitions among atomic orbitals. The most striking feature of the line shapes is their asymmetry, which results from the interference of the resonant and nonresonant cross sections. Smaller resonant enhancements of the magnetic scattering are reported for incident x-ray energies tuned near the L(II) and L(I) absorption edges. C1 AT&T BELL LABS,MURRAY HILL,NJ 07973. CORNELL UNIV,CHESS,ITHACA,NY 14853. INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. RP GIBBS, D (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 49 TC 150 Z9 151 U1 0 U2 9 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 MAR 1 PY 1991 VL 43 IS 7 BP 5663 EP 5681 DI 10.1103/PhysRevB.43.5663 PN A PG 19 WC Physics, Condensed Matter SC Physics GA FA992 UT WOS:A1991FA99200055 ER PT J AU VOLKEL, AR MERTENS, FG BISHOP, AR WYSIN, GM AF VOLKEL, AR MERTENS, FG BISHOP, AR WYSIN, GM TI MOTION OF VORTEX PAIRS IN THE FERROMAGNETIC AND ANTIFERROMAGNETIC ANISOTROPIC HEISENBERG-MODEL SO PHYSICAL REVIEW B LA English DT Article ID TRANSITION; VORTICES; DYNAMICS; MAGNETS; STATES; FILMS AB We study the motion of a pair of unbound vortices in two-dimensional classical spin systems with easy-plane exchange symmetry (XY symmetry). Assuming a velocity-independent shape we derive an equation of motion for one vortex in the presence of the other. The results are compared with a direct molecular-dynamics simulation on a 50 x 10 square lattice at zero temperature. For both the ferromagnet and the antiferromagnet there exists a critical value lambda-c of the anisotropy parameter lambda which separates two regimes with different stable vortex structures. For lambda < lambda-c the spins creating a vortex are essentially in the easy plane and the motion of a poir of vortices is mainly determined by repulsive or attractive forces for equal or different vorticities, respectively. For lambda > lambda-c the vortices have additional out-of-plane spin components which depend on lambda. In the ferromagnetic case these z components are parallel to each other and act effectively on the other vortex like a magnetic field. Together with the attraction or repulsion discussed above, this effective field leads to rotation of the vortices around each other, or to a translation parallel to each other, depending on whether the products of the vorticity and the sign of the out-of-plane components are equal or different for the two vortices. For an antiferromagnetic out-of-plane vortex, however, the z components of the spins are antialigned and therefore do not give an effective magnetic field, here the vortices move essentially on straight lines. In our simulations we observed the above discussed trajectories. The fluctuations around these trajectories due to the discreteness of the lattice are more pronounced for lambda < lambda-c than for lambda > lambda-c. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. UNIV BAYREUTH,INST PHYS,W-8580 BAYREUTH,GERMANY. KANSAS STATE UNIV AGR & APPL SCI,DEPT PHYS,MANHATTAN,KS 66506. RP VOLKEL, AR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Wysin, Gary/I-8162-2012 OI Wysin, Gary/0000-0001-8422-800X NR 24 TC 35 Z9 35 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 MAR 1 PY 1991 VL 43 IS 7 BP 5992 EP 6005 DI 10.1103/PhysRevB.43.5992 PN B PG 14 WC Physics, Condensed Matter SC Physics GA FA993 UT WOS:A1991FA99300023 ER PT J AU VERGES, JA LOUIS, E LOMDAHL, PS GUINEA, F BISHOP, AR AF VERGES, JA LOUIS, E LOMDAHL, PS GUINEA, F BISHOP, AR TI HOLES AND MAGNETIC TEXTURES IN THE 2-DIMENSIONAL HUBBARD-MODEL SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTIVITY; STATE; SYMMETRY; SYSTEM; LIMIT; FLUX AB The Hubbard model in a two-dimensional square lattice is studied within the unrestricted Hartree-Fock approximation. It is shown that a large number of self-consistent solutions exist, which correspond to possible metastable spin and charge configurations. A solution, in which the spins are coplanar and form a vortexlike pattern, is described. The solution is stable over most of the parameter range and dominates for large values of U/t or at high doping. The influence of this multiplicity of solutions on the phase diagram is discussed. C1 UNIV ALICANTE,DEPT FIS APLICADA,E-03080 ALICANTE,SPAIN. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP VERGES, JA (reprint author), UNIV AUTONOMA MADRID,CSIC,INST CIENCIA MAT,E-28049 MADRID,SPAIN. RI Verges, Jose/E-3265-2010; Guinea, Francisco/A-7122-2008 OI Guinea, Francisco/0000-0001-5915-5427 NR 31 TC 116 Z9 116 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 MAR 1 PY 1991 VL 43 IS 7 BP 6099 EP 6108 DI 10.1103/PhysRevB.43.6099 PN B PG 10 WC Physics, Condensed Matter SC Physics GA FA993 UT WOS:A1991FA99300036 ER PT J AU NORMAN, MR AF NORMAN, MR TI POSSIBLE MICROSCOPIC MODEL FOR SUPERCONDUCTIVITY IN UPT3 SO PHYSICAL REVIEW B LA English DT Note ID HEAVY-FERMION SUPERCONDUCTORS; MAGNETIC-FIELD; PHASE-DIAGRAM; SYSTEM UPT3; TRANSITION; FLUCTUATIONS; ANISOTROPY; SCATTERING; TRANSPORT; LATTICE AB Currently, microscopic models based on spin-fluctuation-mediated pairing are at odds with phenomenological theories as regards the symmetry of the order parameter for the heavy-electron superconductor UPt3. The author shows that this discrepancy can be resolved for high-frequency spin fluctuations by including a weak ferromagnetic coupling between next-nearest-neighbor U atoms. RP NORMAN, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Norman, Michael/C-3644-2013 NR 47 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 6121 EP 6123 DI 10.1103/PhysRevB.43.6121 PN B PG 3 WC Physics, Condensed Matter SC Physics GA FA993 UT WOS:A1991FA99300039 ER PT J AU ZHANG, FC NORMAN, MR AF ZHANG, FC NORMAN, MR TI COLLECTIVE MODES OF AN ANYON GAS ON A LATTICE SO PHYSICAL REVIEW B LA English DT Note ID FRACTIONAL-STATISTICS GAS; 2 DIMENSIONS; QUANTUM-MECHANICS; APPROXIMATION; PARTICLES AB We study a tight-binding model for anyons on a square lattice using a self-consistent mean-field theory, where the anyon gauge field is approximated by its expectation value. For any anyon density per site rho-0 = p/q and statistics v = 1 - 1/n, the anyon system has a linear collective mode if and only if q is greater than twice the largest common factor of p and n. The collective mode dispersion, omega(k), is calculated numerically for n = 1 (hard-core bosons) and n = 2 (semions) at certain densities. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP ZHANG, FC (reprint author), UNIV CINCINNATI,DEPT PHYS,CINCINNATI,OH 45221, USA. RI Norman, Michael/C-3644-2013 NR 19 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1991 VL 43 IS 7 BP 6143 EP 6146 DI 10.1103/PhysRevB.43.6143 PN B PG 4 WC Physics, Condensed Matter SC Physics GA FA993 UT WOS:A1991FA99300045 ER PT J AU MUKHOPADHYAY, S LEVENSON, S SEGEL, RE GARINO, G GEESAMAN, D SCHIFFER, JP STEPHANS, G ZEIDMAN, B UNGRICHT, E JACKSON, H KOWALCZYK, R ASHERY, D PIASETSKY, E MOINESTER, M NAVON, I SMITH, LC MINEHART, RC DAS, GS WHITNEY, RR MCKEOWN, R ANDERSON, B MADEY, R WATSON, J AF MUKHOPADHYAY, S LEVENSON, S SEGEL, RE GARINO, G GEESAMAN, D SCHIFFER, JP STEPHANS, G ZEIDMAN, B UNGRICHT, E JACKSON, H KOWALCZYK, R ASHERY, D PIASETSKY, E MOINESTER, M NAVON, I SMITH, LC MINEHART, RC DAS, GS WHITNEY, RR MCKEOWN, R ANDERSON, B MADEY, R WATSON, J TI PION ABSORPTION BY HE-3 AT THE DELTA-RESONANCE ENERGY SO PHYSICAL REVIEW C LA English DT Article ID ISOSPIN DEPENDENCE; NUCLEONS; PI+ AB Pion absorption by 3He was studied at T-pi = 165 MeV in a kinematically complete experiment. The cross section for absorption on a (pn) pair of nucleons, sigma-pn (pi+), was found to be 17.0 +/- 2.6 mb; that for absorption on a (pp) pair, sigma-pp (pi-), 0.91 +/- 0.20 mb. The angular distribution in the pi-NN center-of-mass system for sigma-pn (pi+) resembles that for the pi+ +d-->p + p reaction while the angular distribution for sigma-pp (pi-) is strongly backward peaked. Evidence that a significant fraction of the absorptions involves all three target nucleons is seen in the angular correlation between the two detected nucleons as well as in the momentum distribution of the unobserved nucleon. For pi+ and pi- absorption, the three-body cross sections were found to be 9.6 +/- 2.1 and 4.2 +/- 01.2 mb, respectively. Neither initial- nor final-state interactions appear to be major contributors to the observed three-body absorption, though initial-state interactions may be contributing to the enhancement of the three-body pi+ absorption at the DELTA resonance. C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. TEL AVIV UNIV,DEPT PHYS,IL-69978 TEL AVIV,ISRAEL. UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22901. CALTECH,DEPT PHYS,PASADENA,CA 91125. KENT STATE UNIV,KENT,OH 44242. RP MUKHOPADHYAY, S (reprint author), NORTHWESTERN UNIV,EVANSTON,IL 60201, USA. NR 25 TC 34 Z9 34 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 MAR PY 1991 VL 43 IS 3 BP 957 EP 972 DI 10.1103/PhysRevC.43.957 PG 16 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000010 ER PT J AU ARRIAGA, A PANDHARIPANDE, VR SCHIAVILLA, R AF ARRIAGA, A PANDHARIPANDE, VR SCHIAVILLA, R TI VARIATIONAL MONTE-CARLO CALCULATIONS OF THE H-2 (D,GAMMA)HE4 REACTION AT LOW ENERGIES SO PHYSICAL REVIEW C LA English DT Article ID HE-4 D-STATE; H-2(D,GAMMA)HE-4 REACTION; H-2(D->,GAMMA)HE-4 REACTION; NUCLEI; DEUTERIUM; CAPTURE AB The H-2(d,gamma)He-4 reaction is studied at center-of-mass energies below 500 keV, where it is dominated by the E2 transition from the S5(2) continuum state to the ground state of the alpha particle. Both the S5(2) continuum and the ground states are calculated with the variational Monte Carlo method using the realistic Argonne-nu-14 two-nucleon and Urbana model-VII three-nucleon interactions. A qualitative agreement with the observed cross section is obtained. This reaction can proceed only through the D states in the deuteron and/or in the alpha particle. It is found that, depending upon the continuum wave function, the contributions of the deuteron and alpha-particle D states can either add to produce a large cross section, or cancel. The reaction is thus very sensitive to the continuum wave function. C1 UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. RP ARRIAGA, A (reprint author), UNIV LISBON,CTR FIS NUCL,AVE GAMA PINTO 2,P-1699 LISBON,PORTUGAL. RI Arriaga, Ana/N-2369-2015 OI Arriaga, Ana/0000-0002-8113-7425 NR 35 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 983 EP 991 DI 10.1103/PhysRevC.43.983 PG 9 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000012 ER PT J AU GIBBS, WR GIBSON, BF AF GIBBS, WR GIBSON, BF TI NEUTRON RADIUS ANALYSIS IN THE TRINUCLEON SYSTEM FROM PION-SCATTERING SO PHYSICAL REVIEW C LA English DT Article ID ELASTIC ELECTRON-SCATTERING; DOUBLE-CHARGE-EXCHANGE; MAGNETIC FORM-FACTOR; HIGH MOMENTUM-TRANSFER; TRITON GROUND-STATE; NUCLEON T-MATRIX; SYMMETRY VIOLATION; BINDING-ENERGY; HE-3; H-3 AB We have analyzed recent data for pion elastic scattering on the three-nucleon system to extract the relative neutron-proton radii in He-3 and H-3. Using standard multiple-scattering analysis techniques we determine the difference between the odd radii with an uncertainty of +/- 0.007 fm and that between the even radii within +/- 0.010 fm from the existing data. Additional data and improvements in the scattering theory can be expected to lead to a more precise determination. To assess the significance of the extracted radius differences we compare them with radii determined from Faddeev calculations that include charge-symmetry-breaking forces. RP GIBBS, WR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 67 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1012 EP 1021 DI 10.1103/PhysRevC.43.1012 PG 10 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000015 ER PT J AU FIRESTONE, RB GILAT, J NITSCHKE, JM WILMARTH, PA VIERINEN, KS AF FIRESTONE, RB GILAT, J NITSCHKE, JM WILMARTH, PA VIERINEN, KS TI DECAY STUDIES OF NEUTRON DEFICIENT NUCLEI NEAR THE Z=64 SUBSHELL - DY-142, TB-140, TB-142, GD-140, GD-142, EU-140, EU-142, SM-142, AND PM-142 SO PHYSICAL REVIEW C LA English DT Article ID N = 82; GAMOW-TELLER TRANSITIONS; EQUAL-TO 82; SENIORITY ISOMERISM; ISOTOPE SEPARATOR; BETA-DECAY; STATES; DEFORMATION; N=82 AB The electron-capture and beta-+ -decay branchings (EC/beta-+) and delayed proton decays of A = 142 isotopes with 61 less-than-or-equal-to Z less-than-or-equal-to 66 and A = 140 isotopes with 63 less-than-or-equal-to Z less-than-or-equal-to 65 were investigated with the OASIS facility on-line at the Lawrence Berkeley Laboratory SuperHILAC. Electron capture and positron-decay emission probabilities have been determined for Pm-142 and Sm142 decays, and extensive decay schemes have been constructed for 142Eu(g)(2.34 +/- 0.12 s), 142Gd(70.2 +/- 0.6 s), 140Eu(1.51 +/- 0.02 s), and 140Gd(15.8+/-0.4 s). Decay schemes for for the new isotopes 142Tb(g)(597 +/- 17 ms), 142Tb(m)(303+/-17 ms), 142Dy(2.3+/-0.3 s), 140Eu(m)(125+/- ms), and 140Tb(2.4+/-0.2 s) are also presented. We have assigned gamma rays to these isotopes on the basis of gamma-gamma and x-gamma coincidences, and from half-life determinations. Electron-capture and beta-+ -decay branchings were measured for each decay, and beta-delayed proton branchings were determined for 142Dy, 142Tb, and 140Tb decays. Q(EC) values, derived from the measured EC/beta-+ branchings and the level schemes are compared with those from the Wapstra and Audi mass evaluation and the Liran and Zeldes mass calculation. The systematics of the N = 77 isomer decays are discussed, and the intense 0+ --> 1+ and 1+ --> 0+ ground-state beta decays are compared with shell-model predictions for simple spin-flip transitions. C1 SOREQ NUCL RES CTR,IL-70600 YAVNE,ISRAEL. RP FIRESTONE, RB (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. OI Firestone, Richard/0000-0003-3833-5546 NR 48 TC 25 Z9 27 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 MAR PY 1991 VL 43 IS 3 BP 1066 EP 1085 DI 10.1103/PhysRevC.43.1066 PG 20 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000021 ER PT J AU MORDECHAI, S MORRIS, CL ODONNELL, JM KAGARLIS, MA FINK, D FORTUNE, HT WATSON, DL GILMAN, R WARD, H WILLIAMS, A YOO, SH MOORE, CF AF MORDECHAI, S MORRIS, CL ODONNELL, JM KAGARLIS, MA FINK, D FORTUNE, HT WATSON, DL GILMAN, R WARD, H WILLIAMS, A YOO, SH MOORE, CF TI ANALOG OF THE T-GREATER-THAN GIANT-DIPOLE RESONANCE IN LIGHT-NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID DOUBLE-CHARGE-EXCHANGE; STATE AB Giant resonances were observed in (pi+, pi-) double charge exchange on C-13, Al-27, and Co-59 at excitation energies of 8.8, 14.2, and 27.9 MeV, respectively, where the giant dipoles built on the isobaric analog states are expected to appear. Partial angular distributions were measured for both C-13 and Al-27 and observed to have a dipole shape. The resonance on the T = 1/2 targets has a single isospin value (T = 3/2) and is the analog of the T > giant dipole state in the above nuclei. The results are in good agreement with photonuclear reactions and indicate a new general method for an accurate determination of the T > = T + 1 giant dipole state in T = 1/2 nuclei. C1 UNIV TEXAS,AUSTIN,TX 78712. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV PENN,PHILADELPHIA,PA 19104. UNIV YORK,YORK YO1 5DD,N YORKSHIRE,ENGLAND. RUTGERS STATE UNIV,PISCATAWAY,NJ 08855. CONTINUOUS ELECTRON BEAM ACCLERATOR FACILITY,NEWPORT NEWS,VA 23606. UNIV TEXAS,AUSTIN,TX 78712. RP MORDECHAI, S (reprint author), BEN GURION UNIV NEGEV,IL-84105 BEER SHEVA,ISRAEL. NR 13 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1111 EP 1115 DI 10.1103/PhysRevC.43.1111 PG 5 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000025 ER PT J AU HOIBRATEN, S GILAD, S BURGER, WJ REDWINE, RP PIASETZKY, E BAER, HW BOWMAN, JD CVERNA, FH IROM, F LEITCH, MJ KNUDSON, JN WOOD, SA ROKNI, SH AF HOIBRATEN, S GILAD, S BURGER, WJ REDWINE, RP PIASETZKY, E BAER, HW BOWMAN, JD CVERNA, FH IROM, F LEITCH, MJ KNUDSON, JN WOOD, SA ROKNI, SH TI COINCIDENCE MEASUREMENTS OF THE PI+,PI-0P REACTION AT T-PI+=165 MEV SO PHYSICAL REVIEW C LA English DT Article ID CROSS-SECTIONS; PION AB We report coincidence measurements of the (pi-+,pi-0p) reaction at a beam energy of T-pi + = 165 MeV. The neutral pions were detected by the LAMPF pi-0 spectrometer and the protons by an array of plastic-scintillator telescopes. The resulting energy resolution for the determination of the excitation energy of the residual nucleus was about 10 MeV. Measurements were performed on O-16 at laboratory angles THETA-pi-0 = 70-degrees, 80-degrees, 110-degrees, and 130-degrees. The cross section is predominantly quasifree. Its angular dependence follows the trend of the free single-charge-exchange cross section at back angles and is somewhat suppressed relative to this to more forward angles. Events corresponding to removal of p-shell nucleons were identified by their pi-0 and p energies. The pi-0 energy spectra for such events are compared to similar pion energy spectra for the O-16(pi-+/-,pi-+/-p) reactions; the cross-section ratios are consistent with ratios calculated for isospin coupling alone. pi-0 energy spectra are also compared to predictions of DELTA-hole model calculations; the calculations for events in which protons are detected at the conjugate quasifree angle underestimate the (pi-0,pi-0p) cross sections by 30-55%. At THETA-pi-0 = 110-degrees the (pi-+,pi-0p) reaction was also studied on Fe, Sn, and Pb. No significant A dependence of the cross section was observed. C1 MIT,DEPT PHYS,CAMBRIDGE,MA 02139. MIT,NUCL SCI LAB,CAMBRIDGE,MA 02139. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. ARIZONA STATE UNIV,DEPT PHYS,TEMPE,AZ 85287. TEL AVIV UNIV,SCH PHYS & ASTRON,RAYMOND & BEVERLY SACKLER FAC,IL-69978 TEL AVIV,ISRAEL. UTAH STATE UNIV,DEPT PHYS,LOGAN,UT 84322. NR 25 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1255 EP 1271 DI 10.1103/PhysRevC.43.1255 PG 17 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000039 ER PT J AU KELLY, JJ FELDMAN, AE FLANDERS, BS SEIFERT, H LOPIANO, D AAS, B AZIZI, A IGO, G WESTON, G WHITTEN, C WONG, A HYNES, MV MCCLELLAND, J BERTOZZI, W FINN, JM HYDEWRIGHT, CE LOURIE, RW ULMER, PE NORUM, BE BERMAN, BL AF KELLY, JJ FELDMAN, AE FLANDERS, BS SEIFERT, H LOPIANO, D AAS, B AZIZI, A IGO, G WESTON, G WHITTEN, C WONG, A HYNES, MV MCCLELLAND, J BERTOZZI, W FINN, JM HYDEWRIGHT, CE LOURIE, RW ULMER, PE NORUM, BE BERMAN, BL TI EFFECTIVE INTERACTION FOR O-16(P,P') AT EP=318 MEV SO PHYSICAL REVIEW C LA English DT Article ID NUCLEON-NUCLEUS SCATTERING; 2-NUCLEON EFFECTIVE INTERACTION; ELASTIC-SCATTERING; OPTICAL-MODEL; INTERMEDIATE ENERGIES; MICROSCOPIC DESCRIPTION; IMPULSE-APPROXIMATION; DENSITY DEPENDENCE; PROTON-SCATTERING; EXCHANGE MODEL AB We report new cross-section and analyzing power data for the excitation by 318 MeV protons of 20 states of O-16 below 14 MeV. The data for normal-parity isoscalar excitations are compared with calculations based upon the nonrelativistic impulse approximation using both density-independent and density-dependent interactions in the local-density approximation. These comparisons clearly indicate that density-dependent modifications of the effective interaction are required. Although the Paris-Hamburg, Nakayama-Love, and Ray interactions all predict significant medium modifications, none describes the data particularly well. Therefore, we fitted an empirical effective interaction to the data for five inelastic transitions simultaneously using a self-consistency cycle that maintains consistency between transition potentials and microscopic distorting potentials. This interaction describes the inelastic data as well as elastic data and data for Ca-40 which were not included in the fitting procedure. Therefore, the local-density approximation is supported by the phenomenology. However, medium modifications of the effective interaction are substantially stronger than predicted and persist to low density. The optical potentials are similar to the Schrodinger-equivalent potentials from the relativistic IA2 model, showing that the equivalent density dependence due to virtual NBARN pairs is comparable to the short-range repulsion fitted to inelastic-scattering data. C1 UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. MIT,NUCL SCI LAB,CAMBRIDGE,MA 02139. UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22901. GEORGE WASHINGTON UNIV,DEPT PHYS,WASHINGTON,DC 20052. RP KELLY, JJ (reprint author), UNIV MARYLAND,DEPT PHYS & ASTRON,COLLEGE PK,MD 20742, USA. NR 58 TC 24 Z9 24 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1272 EP 1287 DI 10.1103/PhysRevC.43.1272 PG 16 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000040 ER PT J AU RUGARI, SL FRANCE, RH LUND, BJ SMOLEN, SD ZHAO, Z GAI, M AF RUGARI, SL FRANCE, RH LUND, BJ SMOLEN, SD ZHAO, Z GAI, M TI UPPER LIMITS ON EMISSION OF NEUTRONS FROM TI IN PRESSURIZED D2 GAS CELLS - A TEST OF EVIDENCE FOR COLD FUSION SO PHYSICAL REVIEW C LA English DT Article ID ORDER MULTIPLICITY MEASUREMENTS; GAMMA-DECAY AB We have used a low background detector with high efficiency for detection of bursts to search for emission of neutrons from Ti alloy in pressurized D2 gas cells (cooled to 77 K in liquid nitrogen). Each cell contained between 16 and 67 g of Ti alloy chips and was prepared by methods identical to those used in a recent Los Alamos-Brigham Young University collaboration of Menlove et al. Three to four cells were used in each experimental run, with a total counting time of 103 h, leading to an estimate (based on the early reports of Menlove et al.) of at least four bursts and as many as 12 bursts expected in our experiment. In a later report the burst rate of Menlove et al. is greatly reduced leading to only one or so burst(s) expected in our experiment. The data were analyzed in two modes. In the first mode (singles mode) all detectors were used to search for neutron bursts with an efficiency of 28% for neutron detection and a background of 100 counts per hour (cph). In the second mode (coincidence mode) the neutron time of flight was measured in a search for random emission with an efficiency of 2% and a background of 2 cph. No statistically significant deviations from the background were observed for correlated neutrons emitted in bursts or for neutrons emitted randomly. All events are shown (with 90% confidence) to be consistent with background. For bursts of neutrons we deduce (with 90% confidence) an upper limit on the bursts' size of 50 neutrons. Our upper limit on the random emission of neutrons, 0.008 n/sec (90% confidence), is a factor of 6 to 25 smaller than the range of rates for random emission above background reported by the Los Alamos-Brigham Young University collaboration. C1 BROOKHAVEN NATL LAB,DEPT PHYS & APPL SCI,UPTON,NY 11973. RP RUGARI, SL (reprint author), YALE UNIV,AW WRIGHT NUCL STRUCT LAB,NEW HAVEN,CT 06511, USA. NR 15 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1298 EP 1312 DI 10.1103/PhysRevC.43.1298 PG 15 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000042 ER PT J AU WATSON, DL GILMAN, R MORRIS, CL ZUMBRO, JD MORDECHAI, S BURLEIN, M ODONNELL, JM FORTUNE, HT KOTWAL, A PUTTZ, J SILK, JD MCDONALD, JS MOORE, CF WILLIAMS, AL YOO, SY AF WATSON, DL GILMAN, R MORRIS, CL ZUMBRO, JD MORDECHAI, S BURLEIN, M ODONNELL, JM FORTUNE, HT KOTWAL, A PUTTZ, J SILK, JD MCDONALD, JS MOORE, CF WILLIAMS, AL YOO, SY TI PION-INDUCED DOUBLE CHARGE-EXCHANGE ON C-12, MG-24, S-32, AND CA-40 SO PHYSICAL REVIEW C LA English DT Article ID SHELL-MODEL; NUCLEI AB Angular distributions for pion-induced double-charge-exchange (DCX) reaction have been measured at 164 MeV on the T = 0 target nuclei C-12, Mg-24, and S-32 and Ca-40. The data are compared to calculations using the DELTA-nucleon interaction model with realistic wave functions and pi-N N and rho-N N form factors deduced from fits to previously published DCX data on O-16. The calculations reproduce the general shape of the angular distributions and the absolute magnitude of the cross sections to within a factor of two. C1 RUTGERS STATE UNIV,PISCATAWAY,NJ 08855. CONTINUOUS ELECTRON BEAM ACCELERATOR FACIL,NEWPORT NEWS,VA 23606. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. BEN GURION UNIV NEGEV,IL-84105 BEER SHEVA,ISRAEL. UNIV TEXAS,AUSTIN,TX 78712. UNIV PENN,PHILADELPHIA,PA 19104. RP WATSON, DL (reprint author), UNIV YORK,YORK YO1 5DD,N YORKSHIRE,ENGLAND. NR 15 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 MAR PY 1991 VL 43 IS 3 BP 1318 EP 1320 DI 10.1103/PhysRevC.43.1318 PG 3 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000044 ER PT J AU KIM, HJ DELCAMPO, JG SHAPIRA, D STELSON, PH AF KIM, HJ DELCAMPO, JG SHAPIRA, D STELSON, PH TI MULTINUCLEON-TRANSFER REACTIONS FOR THE 50TI+93NB SYSTEM AT SUBBARRIER AND NEAR-BARRIER ENERGIES SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION FUSION; SUBBARRIER FUSION; COULOMB BARRIER; NECK FORMATION; ENHANCEMENT; NEUTRON; CHANNELS; NI-58 AB Target and target-like ejectiles emitted forward from Nb-93-beam bombardment of thin Ti-50 targets were investigated at sub- and near-barrier energies using a magnetic spectrograph. Reaction products from three single-nucleon-transfer and seven multinucleon-transfer channels were observed. Multinucleon-transfer products were observed with a sharp onset for those collisions with apsidal distances smaller than about 12.6 fm, while single-nucleon-transfer products were observed throughout the apsidal distance range studied. Average Q values of the multinucleon-transfer-reaction products are much more negative than the respective optimum values. These results suggest the formation of a neck at subbarrier energies. C1 LEGNARO NATL LAB,LEGNANO,ITALY. RP KIM, HJ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 25 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1321 EP 1330 DI 10.1103/PhysRevC.43.1321 PG 10 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000045 ER PT J AU WEST, HI MUSTAFA, MG LANIER, RG OBRIEN, H AF WEST, HI MUSTAFA, MG LANIER, RG OBRIEN, H TI INTERPRETATION OF ION-RANGE RECOIL DATA OBTAINED FROM ACTIVATED-FOIL MEASUREMENTS OF NUCLEAR-EXCITATION FUNCTIONS SO PHYSICAL REVIEW C LA English DT Article ID CONTINUUM ANGULAR-DISTRIBUTIONS; SYSTEMATICS AB Ion-range recoil data were obtained during activated-foil measurements of excitation functions for proton-, deuteron-, and triton-induced reactions on selected targets. These data were analyzed by using the Lindhard, Scharf, and Schiott range-energy theory. An important feature of our analysis was the use of angular distributions from the recent Kalbach systematics based on multistep compound and multistep direct reactions. Furthermore, we used the (p,n) data to fix the parameters of LSS theory, and then applied the theory to (d,n), (d,2n), (t,2n), (t,alpha-) and (d,alpha-) reactions. The adjustments to the LSS-theory parameters were less than 10%. The comparisons of the data with calculations demonstrate several important aspects of the reaction mechanisms, e.g., transition from equilibrium to direct reaction, breakup of the deuteron and triton in the reaction entrance channel, and pickup for triton-induced reactions. Overall, the ion-range measurements give a consistent picture of the reaction mechanisms involved. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP WEST, HI (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 21 TC 3 Z9 3 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 MAR PY 1991 VL 43 IS 3 BP 1352 EP 1362 DI 10.1103/PhysRevC.43.1352 PG 11 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000047 ER PT J AU BALTZ, AJ AF BALTZ, AJ TI HEAVY-ION TRANSVERSE ENERGY-PRODUCTION AT 14.5 GEV NUCLEON - SINGLE OR MULTIPLE-SCATTERING SO PHYSICAL REVIEW C LA English DT Article ID P+A COLLISIONS; EMISSION; O+A AB Transverse energy production in nucleus-nucleus collisions is considered in a Glauber model involving the convolution of nucleon-nucleon scattering. A multiple-scattering model with energy production degraded as a function of the number of nucleon interactions fails to reproduce consistently 14.5 GeV/nucleon O-16 data on Au and Cu targets. On the other hand, a single-scattering model, in which each nucleon can interact at most once, is able to reproduce successfully Alternating Gradient Synchrotron proton, O-16, and Si-28 data on various targets. RP BALTZ, AJ (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 7 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 MAR PY 1991 VL 43 IS 3 BP 1420 EP 1424 DI 10.1103/PhysRevC.43.1420 PG 5 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000055 ER PT J AU BAER, HW LEITCH, MJ MISHRA, CS WEINFELD, Z PIASETZKY, E COMFORT, JR TINSLEY, J WRIGHT, DH AF BAER, HW LEITCH, MJ MISHRA, CS WEINFELD, Z PIASETZKY, E COMFORT, JR TINSLEY, J WRIGHT, DH TI PION DOUBLE-CHARGE-EXCHANGE REACTION ON CA-44 AT 50 MEV SO PHYSICAL REVIEW C LA English DT Article ID NUCLEAR SHELL-MODEL; ISOTOPES; C-14 AB Angular distributions of pion double-charge-exchange (DCX) reactions at 50 MeV are reported for the ground-state (g.s.) and the double-isobaric-analog-state (DIAS) transitions on Ca-44. These distributions have similar shapes and magnitudes and are considerably more forward peaked than those of the lighter T = 1 nuclei. The spectra at forward angles exhibit nearly exclusive excitation of the g.s. and DIAS. By using a formulation based on the shell model, the magnitude of the scattering amplitude B associated with nonanalog intermediate state transitions is extracted from the data. C1 TEL AVIV UNIV,IL-69978 TEL AVIV,ISRAEL. ARIZONA STATE UNIV,TEMPE,AZ 85287. TRIUMF,VANCOUVER V6T 2A3,BC,CANADA. RP BAER, HW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 22 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1991 VL 43 IS 3 BP 1458 EP 1461 DI 10.1103/PhysRevC.43.1458 PG 4 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000059 ER PT J AU LIU, LC MA, WH AF LIU, LC MA, WH TI UNITARITY CONSIDERATION OF PION-PRODUCTION IN RELATIVISTIC HEAVY-ION COLLISIONS SO PHYSICAL REVIEW C LA English DT Note ID NUCLEAR-MATTER; DILEPTON AB Pion production in relativistic heavy-ion collisions is examined with the use of the unitarity relation. We show that the density of states for pion production in an absorptive nuclear medium is not inversely proportional to the in-medium pion group velocity; it depends equally on the imaginary part of the pion self-energy. C1 CHINESE ACAD SCI,INST SOCIAL WELF,BEIJING,PEOPLES R CHINA. RP LIU, LC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,T-2,LOS ALAMOS,NM 87545, USA. NR 12 TC 3 Z9 3 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 MAR PY 1991 VL 43 IS 3 BP R935 EP R938 DI 10.1103/PhysRevC.43.R935 PG 4 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000004 ER PT J AU RANGACHARYULU, C RICHTER, A WORTCHE, HJ ZIEGLER, W CASTEN, RF AF RANGACHARYULU, C RICHTER, A WORTCHE, HJ ZIEGLER, W CASTEN, RF TI STRONG CORRELATION AND SATURATION OF E2 AND M1 TRANSITION STRENGTHS IN EVEN-EVEN RARE-EARTH NUCLEI SO PHYSICAL REVIEW C LA English DT Note ID INELASTIC ELECTRON-SCATTERING; DIPOLE EXCITATIONS; HEAVY-NUCLEI; GD-156; DY-164; MODE; DEFORMATION; STATES AB In heavy deformed even-even nuclei the orbital M 1 strength below 4 MeV excitation, the so-called "scissors mode," shows a striking correlation with the E 2 strength to the first excited 2+ states. A saturation effect, common to both E 2 and M 1 transitions, is observed before midshell. The correlation and the saturation effect are discussed. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP RANGACHARYULU, C (reprint author), TH DARMSTADT,INST KERNPHYS,W-6100 DARMSTADT,GERMANY. NR 24 TC 91 Z9 91 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 MAR PY 1991 VL 43 IS 3 BP R949 EP R951 DI 10.1103/PhysRevC.43.R949 PG 3 WC Physics, Nuclear SC Physics GA FA990 UT WOS:A1991FA99000008 ER PT J AU STRASSLER, MJ PESKIN, ME AF STRASSLER, MJ PESKIN, ME TI THRESHOLD PRODUCTION OF HEAVY TOP QUARKS - QCD AND THE HIGGS BOSON SO PHYSICAL REVIEW D LA English DT Article ID BOUND-STATES; QUANTUM CHROMODYNAMICS; E+E-ANNIHILATION; CROSS-SECTION; QUARKONIUM; PAIR AB We calculate the threshold cross section for e+e- --> ttBAR to leading-logarithmic order in QCD, using a nonrelativistic approximation suggested by Fadin and Khoze. We study the mass range 100 less-than-or-equal-to m(t) less-than-or-equal-to 250 GeV, and show that the cross section is an excellent measure of alpha-s for the lower portion of the mass range, while for a heavier top quark it is sensitive to the mass and couplings of the Higgs boson. We argue that a precise determination of m(t) and a measurement of GAMMA-t are possible. We also show that nonperturbative effects are small, confirming that the ttBAR threshold is a detailed perturbative test of the standard model. RP STRASSLER, MJ (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 24 TC 177 Z9 177 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 MAR 1 PY 1991 VL 43 IS 5 BP 1500 EP 1514 DI 10.1103/PhysRevD.43.1500 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600006 ER PT J AU BIYAJIMA, M FOWLER, GN FRIEDLANDER, EM SHIH, CC SUZUKI, N WEINER, RM WILK, G AF BIYAJIMA, M FOWLER, GN FRIEDLANDER, EM SHIH, CC SUZUKI, N WEINER, RM WILK, G TI DERIVATION OF THE 2-COMPONENT MODEL FOR MULTIPLICITY DISTRIBUTIONS FROM A STOCHASTIC BRANCHING MECHANISM SO PHYSICAL REVIEW D LA English DT Article ID DIFFERENTIAL-DIFFERENCE EQUATION; CHARGED-PARTICLE MULTIPLICITY; HADRONIC COLLISIONS; PROTON COLLISIONS; PP INTERACTIONS; MCGILL FORMULA; CROSS-SECTIONS; QCD JETS; ENERGY; GEV/C AB Multiplicity distributions in high-energy hadronic reactions are broader in the central rapidity region than in the fragmentation region. An explanation of this phenomenon in terms of a stochastic branching equation is given supporting the picture of two sources, one mainly chaotic and one essentially coherent. C1 SHINSHU UNIV,FAC LIBERAL ARTS,DEPT PHYS,MATSUMOTO,NAGANO 390,JAPAN. UNIV EXETER,DEPT PHYS,EXETER EX4 4RJ,DEVON,ENGLAND. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. MATSUSHO GAKUEN JUNIOR COLL,MATSUMOTO 39012,JAPAN. SOLTAN INST NUCL STUDIES,WARSAW,POLAND. RP BIYAJIMA, M (reprint author), UNIV MARBURG,DEPT PHYS,W-3550 MARBURG,GERMANY. NR 37 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP 1541 EP 1547 DI 10.1103/PhysRevD.43.1541 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600010 ER PT J AU CHENG, HY AF CHENG, HY TI DIRECT CP VIOLATION IN K -]3-PI DECAY SO PHYSICAL REVIEW D LA English DT Article ID CHIRAL PERTURBATION-THEORY; K->3-PI DECAYS; MATRIX-ELEMENTS; 6-QUARK MODEL; KAON DECAY; LARGE MT; EPSILON'/EPSILON; ANOMALIES; LATTICE; QUARK AB In light of the fact that the presence of the Z0 penguin diagram suppresses strongly epsilon-2-pi-'/epsilon in K0 --> 2-pi decay for large values of m(t), we reanalyze the direct decay-amplitude CP violation in K0 --> 3-pi decays in the Kobayashi-Maskawa model. The effects due to electroweak penguins, isospin breaking, and higher-order weak chiral Lagrangians are studied in the large-N(c) approach. We find that the Li-Wolfenstein relation between epsilon-3-pi-' and epsilon-2-pi-' is modified dramatically: the former receives very large contributions from the higher-derivative chiral terms and sizable contributions from the isospin-breaking correction due to pi-0-eta-eta' mixing and eta, eta' --> 3-pi transitions. When the top quark becomes very heavy, effects of the electroweak penguin terms are enhanced. Unlike epsilon-2-pi-'/epsilon, which decreases as m(t) increases, the CP-violating parameter epsilon-3-pi-'/epsilon is of order 10(-2) and increases with the heavy top-quark mass. C1 ACAD SINICA,INST PHYS,TAIPEI 11529,TAIWAN. RP CHENG, HY (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 37 TC 9 Z9 9 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 MAR 1 PY 1991 VL 43 IS 5 BP 1579 EP 1592 DI 10.1103/PhysRevD.43.1579 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600016 ER PT J AU DUNIETZ, I SNYDER, A AF DUNIETZ, I SNYDER, A TI NO FINAL-STATE PHASE AMBIGUITIES IN ADDITIONAL BD DECAYS WITH LARGE CP VIOLATION SO PHYSICAL REVIEW D LA English DT Article ID MESONS AB The B(d) decay modes DBAR0(DBAR*0)X0 generated by the quark process bBAR-->cBAR + udBAR have a large CP asymmetry within the Cabibbo-Kobayashi-Maskawa (CKM) model. Here X0 denotes a light, neutral meson with zero strangeness, such as pi-0, rho-0, omega, etc. This asymmetry depends only on a ratio of CKM matrix elements and not on final-state phases. The CKM model predicts (up to a sign) the same asymmetries for the DBAR0(DBAR*0)X0, psi-K(s), and D+D- modes. Adding those modes might lower the required luminosity for observing CP violation within the CKM model. On the other hand, future high-statistics measurements could reveal violations of the CKM model simply by demonstrating that the modes psi-K(s), D+D- and DBAR0(DBAR*0)X0 differ in their individual CP asymmetries. C1 INDIANA UNIV,BLOOMINGTON,IN 47401. RP DUNIETZ, I (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 22 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP 1593 EP 1598 DI 10.1103/PhysRevD.43.1593 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600017 ER PT J AU CARLSON, J PANDHARIPANDE, VR AF CARLSON, J PANDHARIPANDE, VR TI ABSENCE OF EXOTIC HADRONS IN FLUX-TUBE QUARK MODELS SO PHYSICAL REVIEW D LA English DT Article ID DIBARYON RESONANCES; BAG MODEL; BARYONS; STATES; DECAY; SPECTROSCOPY; STABILITY; QCD AB Flux-tube quark models based upon strong-coupling QCD are studied in the limit of small coupling between different flux-tube topologies. In this limit, it is shown that no bound exotic states exist, in contrast with predictions made with bag and other mean-field and two-body potential quark models. Results are presented for the 2q-2qBAR, 4q-qBAR, and 6q sectors, and the various quark models are compared. The extent to which "exotic" states are observed experimentally can be regarded to some degree as a test of the relevance of strong-coupling-based flux-tube models. C1 UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. RP CARLSON, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,T-5,MS B283,LOS ALAMOS,NM 87545, USA. NR 33 TC 42 Z9 43 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP 1652 EP 1658 DI 10.1103/PhysRevD.43.1652 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600022 ER PT J AU WILLENBROCK, S AF WILLENBROCK, S TI PADE AND K-MATRIX APPROXIMATIONS TO THE O(2N) MODEL FOR LARGE N SO PHYSICAL REVIEW D LA English DT Article ID HIGGS-BOSON MASS; STANDARD MODEL; FIELD-THEORY; RENORMALIZATION-GROUP; SYMMETRY BREAKING; SIGMA-MODEL; O(N) MODEL; SCATTERING; TRIVIALITY; SECTOR AB The Pade approximation and the K matrix are techniques for constructing perturbative amplitudes which satisfy two-body unitarity exactly. We apply these approximations to the Goldstone-boson scattering amplitude in a spontaneously broken O(2N) model, in the large-N limit, and compare with the exact amplitude (to leading order in 1/N). The [r,r] Pade approximation reproduces the exact large-N amplitude for all r. The K matrix, at any finite order, yields an amplitude which is qualitatively similar to, but not identical to, the exact amplitude. RP BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. NR 40 TC 13 Z9 13 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP 1710 EP 1716 DI 10.1103/PhysRevD.43.1710 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600027 ER PT J AU ALEXANDREAS, DE ALLEN, RC BERLEY, D BILLER, SD BURMAN, RL CADY, DR CHANG, CY DINGUS, BL DION, GM ELLSWORTH, RW GILRA, MK GOODMAN, JA GUPTA, S HAINES, TJ HOFFMAN, CM KRAKAUER, DA KWOK, P LLOYDEVANS, J LU, XQ NAGLE, DE POTTER, ME SANDBERG, VD STARK, MJ TALAGA, RL VISHWANATH, PR YODH, GB ZHANG, W AF ALEXANDREAS, DE ALLEN, RC BERLEY, D BILLER, SD BURMAN, RL CADY, DR CHANG, CY DINGUS, BL DION, GM ELLSWORTH, RW GILRA, MK GOODMAN, JA GUPTA, S HAINES, TJ HOFFMAN, CM KRAKAUER, DA KWOK, P LLOYDEVANS, J LU, XQ NAGLE, DE POTTER, ME SANDBERG, VD STARK, MJ TALAGA, RL VISHWANATH, PR YODH, GB ZHANG, W TI OBSERVATION OF SHADOWING OF ULTRAHIGH-ENERGY COSMIC-RAYS BY THE MOON AND THE SUN SO PHYSICAL REVIEW D LA English DT Article ID CYGNUS-X-3; SIGNALS; SEARCH; 50-TEV AB Data from an extensive air shower detector of ultrahigh-energy cosmic rays shows shadowing of the cosmic-ray flux by the Moon and the Sun with significance of 4.9 standard deviations. This is the first observation of such shadowing. The effect has been used to determine that the angular resolution of the detector is 0.75-degrees-0.09-degrees+0.13-degrees. C1 UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV NOTRE DAME,NOTRE DAME,IN 46556. GEORGE MASON UNIV,FAIRFAX,VA 22030. RP ALEXANDREAS, DE (reprint author), UNIV CALIF IRVINE,IRVINE,CA 92717, USA. RI Zhang, William/D-3535-2012; OI Dingus, Brenda/0000-0001-8451-7450 NR 13 TC 40 Z9 41 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP 1735 EP 1738 DI 10.1103/PhysRevD.43.1735 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600030 ER PT J AU BARGER, V WHISNANT, K AF BARGER, V WHISNANT, K TI CAN MINIMAL SUPERSYMMETRY BE RULED OUT AT CERN LEP-200 FROM E+E--]Z-PHI HIGGS-BOSON SEARCHES SO PHYSICAL REVIEW D LA English DT Note AB We show that if the CERN collider LEP 200 is capable of excluding a standard-model Higgs boson with m-phi = m(z) via the process e+e- --> Z-phi --> l+l- qqBAR, then the minimal supersymmetric model would also be excluded by similar searches for the light and heavy neutral Higgs scalars of minimal supersymmetry. We discuss how this might be achieved using the production rate and final-state particle distributions. An integrated luminosity of about 4 fb-1 should be sufficient to exclude at the 4-sigma level a standard-model Higgs boson with m-phi = m(z); with b tagging, 0.7 fb-1 may suffice. If a positive Higgs-boson signal is seen, minimal supersymmetry might not be distinguishable from the standard model in the Z-phi mode alone. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP BARGER, V (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. NR 24 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1991 VL 43 IS 5 BP R1443 EP R1447 DI 10.1103/PhysRevD.43.R1443 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ726 UT WOS:A1991EZ72600001 ER PT J AU DURKEE, JW ANTICH, PP AF DURKEE, JW ANTICH, PP TI EXACT-SOLUTIONS TO THE MULTIREGION TIME-DEPENDENT BIOHEAT EQUATION WITH TRANSIENT HEAT-SOURCES AND BOUNDARY-CONDITIONS SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID BLOOD-FLOW; SKIN AB Exact solutions to the classical time-dependent linear bioheat equation, in one-dimensional multi-region Cartesian, cylindrical and spherical geometries with temperature-invariant physiological parameters, are derived and computationally evaluated. Earlier work is extended to accommodate transient heat sources and boundary conditions using the method of multi-region Green's functions. These solutions enable the study of transient temperature behaviour in an arbitrary number of coupled physiologically distinct regions, when regional heating rates and/or external temperatures vary with time. Such behaviour is graphically illustrated using previously reported results for parametric and idealized upper thigh and tumour model calculations that are reconsidered for their response to transient heat sources and boundary temperatures. C1 UNIV TEXAS,SW MED CTR,DALLAS,TX 75235. RP DURKEE, JW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 15 TC 22 Z9 22 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0031-9155 J9 PHYS MED BIOL JI Phys. Med. Biol. PD MAR PY 1991 VL 36 IS 3 BP 345 EP 368 DI 10.1088/0031-9155/36/3/004 PG 24 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA FB164 UT WOS:A1991FB16400004 ER PT J AU PARK, W MONTICELLO, DA FREDRICKSON, E MCGUIRE, K AF PARK, W MONTICELLO, DA FREDRICKSON, E MCGUIRE, K TI FINITE PRESSURE EFFECTS ON SAWTOOTH OSCILLATIONS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Letter ID TOKAMAKS; SAWTEETH AB Nonlinear 3-D simulation of sawtooth oscillations shows that the helically twisted hot spot has a prominent toroidal bulge at the large major radius side, characteristic of a high-epsilon-beta-p instability. This bulge drives other m/n islands just outside the mixing radius resulting in a stochastic annular region. A similar effect is also found in shaped plasmas, even at low beta. These effects agree with experimental data, giving detailed support to the Kadomtsev reconnection model. This effect can also be used to explain the experimental sawtooth heat pulse "anomaly." At high epsilon-beta-p, the stochastic region can essentially fill the whole plasma, and can result in a "high-beta disruption." RP PARK, W (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 13 TC 29 Z9 29 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 MAR PY 1991 VL 3 IS 3 BP 507 EP 510 DI 10.1063/1.859899 PG 4 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000001 ER PT J AU YOSHIKAWA, S CHENG, CZ AF YOSHIKAWA, S CHENG, CZ TI PROPAGATION OF DRIFT WAVES IN TOROIDAL PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID STABILITY; MODES AB Drift wave patterns in toroidal plasmas are studied. The dispersion relation was simplified to retain both the shear and the toroidal coupling effects. Since the dispersion relation does not depend on the toroidal angle phi the dispersion is solved in the two-dimensional space made up with minor radius and poloidal angle. The dispersion relation can be reduced into second-order, partial differential equations of a hyperbolic type. The one-dimensional convective mode analysis, which was originated in the 1960s, was extended into the two-dimensional analysis. Depending on the strengths of the magnetic shear, one can obtain either convective or localized solutions. The results show that the plasma is expected to be unstable for large azimuthal mode number and that the plasma instability tends to be more stabilized for large mass ions. RP YOSHIKAWA, S (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. RI Cheng, Chio/K-1005-2014 NR 17 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 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAR PY 1991 VL 3 IS 3 BP 523 EP 528 DI 10.1063/1.859902 PG 6 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000005 ER PT J AU BRAVOORTEGA, A GLASSER, AH AF BRAVOORTEGA, A GLASSER, AH TI THEORY AND APPLICATION OF COMPLEX GEOMETRIC OPTICS IN INHOMOGENEOUS MAGNETIZED PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article AB A new treatment is presented of geometric optics in inhomogeneous, magnetized plasmas with non-Hermitian dielectric tensors. Previous treatments assume either that the dielectric tensor is nearly Hermitian or that the frequency is nearly real. This is done in order to restrict the values of space-time coordinates along a ray to real values. This work eliminates this restriction, gives a new interpretation of the meaning of complex-valued coordinates, and shows that it extends the range of validity of the theory. This derivation is fully covariant, eliminating the special role played by the time in previous derivations. A new numerical treatment of the amplitude equation, which may be more convenient than ray tracing, is suggested. An application of the method of complex ray tracing to lower hybrid wave propagation in a tokamak is introduced. C1 AUBURN UNIV,DEPT PHYS,AUBURN,AL 36849. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 5 TC 17 Z9 17 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAR PY 1991 VL 3 IS 3 BP 529 EP 537 DI 10.1063/1.859903 PG 9 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000006 ER PT J AU HOLMES, JA AF HOLMES, JA TI NONLINEAR EVOLUTION OF RESISTIVE MODES FOR Q-LESS-THAN-1 IN TOKAMAKS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID TOROIDAL GEOMETRY; EQUATIONS AB The nonlinear interaction of tearing instabilities resonant inside the q = 1 surface can lead to stochastization of the plasma core without involving the n = 1 mode. For certain profiles, the q = 1 surface can survive this disruption, so that q < 1 remains valid inside. These results are consistent with some experimental sawtooth observations in which q < 1 occurs in the core even after the disruption. The competition between this process and the usual resistive reconnection of the (m = 1)/(n = 1) magnetic island can be sensitive to the initial perturbation as well as to the plasma configuration and profiles. RP HOLMES, JA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 12 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 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAR PY 1991 VL 3 IS 3 BP 594 EP 600 DI 10.1063/1.859857 PG 7 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000013 ER PT J AU WAELBROECK, FL CHEN, L AF WAELBROECK, FL CHEN, L TI BALLOONING INSTABILITIES IN TOKAMAKS WITH SHEARED TOROIDAL FLOWS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID AXISYMMETRIC PLASMAS; CYLINDRICAL PLASMA; EQUILIBRIUM FLOWS; ROTATING PLASMAS; MODES; STABILITY; SPECTRUM; IDEAL AB The stability of ballooning modes in the presence of sheared toroidal flows is investigated. The eigenmodes are shown to be related by a Fourier transformation to the nonexponentially growing Floquet solutions found by Cooper [Plasma Phys. Controlled Fusion 30, 1805 (1988)]. It is further shown that the problem cannot be reduced further than to a two-dimensional partial differential equation. Next, the generalized ballooning equation is solved analytically for a circular tokamak equilibrium with sonic flows, but with a small rotation shear compared to the sound speed. With this ordering, the centrifugal forces are comparable to the pressure gradient forces driving the instability, but coupling of the mode with the sound wave is avoided. A new stability criterion is derived that explicitly demonstrates that flow shear is stabilizing at constant centrifugal force gradient. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RI Waelbroeck, Francois/B-6988-2008; chen, liu/I-2297-2013 OI Waelbroeck, Francois/0000-0001-9324-3690; NR 36 TC 98 Z9 99 U1 0 U2 8 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 MAR PY 1991 VL 3 IS 3 BP 601 EP 610 DI 10.1063/1.859858 PG 10 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000014 ER PT J AU TSANG, KT CHENG, CZ AF TSANG, KT CHENG, CZ TI GYROKINETIC SIMULATION OF MICROINSTABILITIES IN HIGH-TEMPERATURE TOKAMAKS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PARTICLE SIMULATION; TOROIDAL PLASMAS; INSTABILITY; WAVES; MODES AB A new numerical approach to investigate the stability of low-frequency fluctuations in high temperature tokamaks is developed by solving the gyrokinetic equations for the ion and electron directly as an initial value problem. The advantage of this approach is the inclusion of many important kinetic features of the problem without approximations. The ion-temperature-gradient mode is investigated as an example of this new simulation technique. Both the adiabatic electron model and the full drift-kinetic electron model are studied. Numerical results show that the full drift-kinetic electron model is more unstable. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP TSANG, KT (reprint author), SCI APPLICAT INT CORP,APPL PHYS OPERAT,1710 GOODRIDGE DR,MCLEAN,VA 22102, USA. RI Cheng, Chio/K-1005-2014 NR 17 TC 10 Z9 11 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 MAR PY 1991 VL 3 IS 3 BP 688 EP 695 DI 10.1063/1.859865 PG 8 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000021 ER PT J AU GOLDMAN, MV WILLIAMS, EA AF GOLDMAN, MV WILLIAMS, EA TI TIME-DEPENDENT PHASE CONJUGATION AND 4-WAVE-MIXING IN PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID KERR MEDIA; WAVE; INSTABILITIES AB Time-dependent four-wave mixing and phase conjugation in plasmas are treated, taking into account resonant longitudinal plasma modes and effects of spatial nonuniformity. A space-time formulation of four-wave processes in the ponderomotive force regime yields linearized equations, which are solved analytically as a combined initial/boundary-value problem in slab and inhomogeneous geometries. The plasma response is incorporated in a "grating" Green's function, expressed in terms of linear quasilongitudinal susceptibilities. Response times, decay times, and absolute instabilities are treated analytically. Plasma nonuniformity can speed up the response of the conjugate wave and modify resonant absolute instability thresholds. A new class of resonant absolute instabilities occurs when the counterpropagating pump waves have unequal intensities. The thresholds can be rather low for pump waves of modest intensity, provided the resonant grating has a long lifetime. Below these thresholds, regimes of stable amplification of the phase-conjugate wave relative to the incident signal are possible with pumps of unequal intensity. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP GOLDMAN, MV (reprint author), UNIV COLORADO,CAMPUS BOX 391,BOULDER,CO 80309, USA. NR 27 TC 22 Z9 22 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 MAR PY 1991 VL 3 IS 3 BP 751 EP 765 DI 10.1063/1.859871 PG 15 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000028 ER PT J AU COHEN, BI LASINSKI, BF LANGDON, AB CUMMINGS, JC AF COHEN, BI LASINSKI, BF LANGDON, AB CUMMINGS, JC TI DYNAMICS OF PONDEROMOTIVE SELF-FOCUSING IN PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID ELECTROMAGNETIC-WAVES; PARAMETRIC-INSTABILITIES; MAGNETIZED PLASMA; LASER-BEAMS; FILAMENTATION; RADIATION; LIGHT AB The space-time evolution of nonlinear self-focusing of a coherent electromagnetic beam in a plasma is calculated. Parameters are considered for which the dominant nonlinearity is the ponderomotive force and the plasma response is hydrostatic. A simple nonlinear wave equation with a saturable, exponential nonlinearity is presented and solved in the paraxial limit. Nondimensional scaled variables are introduced, and both steady-state and time-dependent numerical solutions of the scaled equation are calculated in the limit of cylindrical symmetry. Self-focusing can be important both for high-power lasers in inertial-confinement-fusion applications and for heating of magnetically confined plasmas with intense, pulsed free-electron lasers. RP COHEN, BI (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 29 TC 37 Z9 37 U1 0 U2 6 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 MAR PY 1991 VL 3 IS 3 BP 766 EP 775 DI 10.1063/1.859872 PG 10 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000029 ER PT J AU HOSHINO, M ARONS, J AF HOSHINO, M ARONS, J TI PREFERENTIAL POSITRON HEATING AND ACCELERATION BY SYNCHROTRON MASER INSTABILITIES IN RELATIVISTIC POSITRON-ELECTRON-PROTON PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID CRAB-NEBULA; RADIATION; SHOCKS AB In this paper, a new process of the preferential strong heating of positrons through the ion synchrotron maser instability in positron-electron-proton (e+ -e- -p+) magnetized plasmas is studied, using particle-in-cell simulations. It is found that the positrons form a nonthermal power-law-like energy distribution through their gyroresonant interaction with the extraordinary modes emitted by the ions. This process may be important for the shock excitation of the nonthermal synchrotron radiation observed from astrophysical systems powered by relativistic outflows from compact central objects (e.g., supernova remnants powered by pulsars and jets from active galactic nuclei). When the initial particle distributions are cold rings in momentum space for all three species, there are two stages of instability. The electrons and positrons first thermalize through the emission of collective extraordinary modes. This phase is followed by the emission of collective proton synchrotron radiation, a process with a slower growth rate than the maser in the e- and e+. When the gyrational energy density of the protons exceeds that of the e+, a significant amount of energy can be transferred to the positrons through resonant interaction between the e+, which gyrate in the same sense as the p+, and the elliptically polarized proton synchrotron modes whose frequency is at high harmonics of the fundamental proton gyrofrequency and whose electric field vector has the same sense of rotation as the protons and positrons. The final spectrum of the positrons has a power-law distribution in energy space: The number of positrons with relativistic energy between E and E + dE is N(E)dE proportional-To E-2. The electrons, which have the opposite sense of gyromotion to the protons, are not accelerated and retain the relativistic Maxwellian distribution that results from the synchrotron maser instability in the pairs alone. A brief discussion of the relevance of these results to the structure of collisionless relativistic shock waves in astrophysical sources of synchrotron radiation is presented. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. RP HOSHINO, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550, USA. NR 28 TC 41 Z9 41 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAR PY 1991 VL 3 IS 3 BP 818 EP 833 DI 10.1063/1.859877 PG 16 WC Physics, Fluids & Plasmas SC Physics GA EZ400 UT WOS:A1991EZ40000034 ER PT J AU VARNER, RL THOMPSON, WJ MCABEE, TL LUDWIG, EJ CLEGG, TB AF VARNER, RL THOMPSON, WJ MCABEE, TL LUDWIG, EJ CLEGG, TB TI A GLOBAL NUCLEON OPTICAL-MODEL POTENTIAL SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID NEUTRON ELASTIC-SCATTERING; POLARIZED PROTONS; INELASTIC-SCATTERING; VOLUME INTEGRALS; FINITE NUCLEI; DENSITY DISTRIBUTIONS; COULOMB CORRECTION; ANALYZING POWERS; PB-208; DEPENDENCE AB We describe a new parametrization of the nucleon-nucleus optical-model potential based on data for A = 40 to 209, proton energies of 16 to 65 MeV and neutron energies of 10 to 26 MeV, including extensive polarized-beam data. This parametrization, called CH89, is based on the current understanding of the basis of the optical potential, such as the folding model and nuclear matter approaches. It differs significantly from previous global parametrizations, especially in the weakness of the isovector potential, the parametrization of potential radii, and the smooth variation of imaginary-potential depths with energy. We also describe an optical-model parameter search system, MINOPT, based on the minimization program MINUIT. It is applied to analyze simultaneously a large database of nearly 300 carefully selected angular distributions. Parameter uncertainties and correlations between parameters are estimated by using the non-parametric statistical technique known as the bootstrap method. CH89 is intended to serve as a starting point for definitive tests of models of the nucleon-nucleus interaction, and to be of immediate use for applications. C1 DUKE UNIV,TRIANGLE UNIV NUCL LAB,DURHAM,NC 27706. UNIV N CAROLINA,DEPT PHYS & ASTRON,CHAPEL HILL,NC 27599. RP VARNER, RL (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 105 TC 346 Z9 353 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD MAR PY 1991 VL 201 IS 2 BP 57 EP 119 DI 10.1016/0370-1573(91)90039-O PG 63 WC Physics, Multidisciplinary SC Physics GA FD844 UT WOS:A1991FD84400001 ER PT J AU GILMAN, JJ AF GILMAN, JJ TI RESEARCH MANAGEMENT TODAY SO PHYSICS TODAY LA English DT Article RP GILMAN, JJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 15 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 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1991 VL 44 IS 3 BP 42 EP 48 DI 10.1063/1.881283 PG 7 WC Physics, Multidisciplinary SC Physics GA FB711 UT WOS:A1991FB71100011 ER PT J AU STAINES, K BALOGH, A COWLEY, SWH HYNDS, RJ YATES, TS RICHARDSON, IG SANDERSON, TR WENZEL, KP MCCOMAS, DJ TSURUTANI, BT AF STAINES, K BALOGH, A COWLEY, SWH HYNDS, RJ YATES, TS RICHARDSON, IG SANDERSON, TR WENZEL, KP MCCOMAS, DJ TSURUTANI, BT TI COMETARY WATER-GROUP IONS IN THE REGION SURROUNDING COMET GIACOBINI-ZINNER - DISTRIBUTION-FUNCTIONS AND BULK PARAMETER ESTIMATES SO PLANETARY AND SPACE SCIENCE LA English DT Article ID SOLAR-WIND PLASMA; FREQUENCY ELECTROMAGNETIC-WAVES; MAGNETIC-FIELD OBSERVATIONS; HALLEY BOW SHOCK; P/GIACOBINI-ZINNER; ENERGETIC IONS; PICKUP IONS; HEAVY-IONS; ISEE-C; INSITU OBSERVATIONS AB The bulk parameters (number density and thermal energy density) of cometary water-group ions in the region surrounding comet Giacobini-Zinner have been derived using data from the EPAS instrument on the ICE spacecraft. The derivation is based on the assumption that the pick-up ion distribution function is isotropic in the frame of the bulk flow, an approximation which has previously been shown to be reasonable within approximately 4 x 10(5) km of the comet nucleus along the spacecraft trajectory (corresponding to +/- 5 h about closest approach). Bulk parameter determinations are consequently restricted to this region, which corresponds physically to the inner part of the region of cometary ion pick-up in the solar wind flow, and the interior region of slowed, mass-loaded flow. The transition between the pick-up and mass-loaded regions occurs at the cometary shock, which was traversed at a cometocentric distance of approximately 1 x 10(5) km along the spacecraft track (+/- 85 min about closest approach). Examination of the ion distribution functions in this region, transformed to the bulk flow frame, indicates the occurrence of a "flattened" distribution in the vicinity of the local pick-up speed, and a steeply falling tail at speeds above, which may be approximated as an exponential in ion speed. Bulk parameters derived by integrating over these distributions have been compared with simple theoretical estimates based on ionization of the neutral coma of the comet by solar u.v. radiation, by charge exchange, and by electron impact, giving a combined ionization time-scale of approximately 10(6) s, followed by ion pick-up and isotropization in the solar wind flow. In the inner pick-up region the derived parameters are in good agreement with the theoretical estimates, within a factor of approximately 2, showing that no major additional sources of ionization, or major energization processes, are required to account for the results. Comparison of the thermal pressure of the water-group pick-up ions with the solar wind thermal pressure and with the magnetic pressure, shows how the pick-up ion pressure grows from small values at large distances from the comet, to become the dominant pressure component in the region just upstream from the shock. As a consequence, the magnetosonic Mach number falls from values of approximately 5 at large distances, down to approximately 2.5 just upstream of the shock. In the mass-loaded region downstream from the shock the observed ions most probably correspond to the relatively energetic population which is produced in the fast-flow region upstream from the shock, and which is subsequently convected downstream. Reasonable agreement between derived and theoretically-estimated bulk parameters is obtained in the outer part of the mass-loaded region on this basis. In the inner part of the mass-loaded region, however, within approximately 6 x 10(4) km of the comet (+/- 45 min about closest approach), the derived densities fall far below theoretical predictions, indicating that the energetic ions created in the upstream region must be actively removed from these stream-tubes by some process, at present undetermined. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. EUROPEAN SPACE AGCY,EUROPEAN SPACE RES & TECHNOL CTR,DEPT SPACE SCI,2200 AG NOORDWIJK,NETHERLANDS. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP STAINES, K (reprint author), UNIV LONDON IMPERIAL COLL SCI & TECHNOL,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. OI Richardson, Ian/0000-0002-3855-3634 NR 62 TC 9 Z9 9 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAR PY 1991 VL 39 IS 3 BP 479 EP 506 DI 10.1016/0032-0633(91)90008-X PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FF040 UT WOS:A1991FF04000008 ER PT J AU GOYAL, A HISER, C TOLBERT, NE MCINTOSH, L AF GOYAL, A HISER, C TOLBERT, NE MCINTOSH, L TI PROGRESS-9 CULTIVAR OF PEA HAS ALTERNATIVE RESPIRATORY CAPACITY AND NORMAL GLYCINE METABOLISM SO PLANT AND CELL PHYSIOLOGY LA English DT Article DE ALTERNATIVE OXIDASE; CYANIDE-RESISTANT RESPIRATION; GLYCINE OXIDATION; PEA MITOCHONDRIA ID CYANIDE-RESISTANT RESPIRATION; HIGHER-PLANT MITOCHONDRIA; OXIDASE; PATH; CO2 AB Mitochondria from the dwarf pea cultivar Progress No. 9, have been reported to lack alternative respiration. However, the rates of respiration with succinate and malate by mitochondria isolated from Progress No. 9, although approximately 30% lower than those from Alaska, had the same percentage distribution of respiratory capacity between the cytochrome pathway and the alternative pathway. Immunoblots showed both cultivars contain polypeptides identified as components of the alternative oxidase. Both cultivars formed identical products during photosynthetic (14CO)-C-14 fixation, and the percentage distribution of C-14 into glycine and serine were similar. In spite of large amounts of glycine decarboxylase in the isolated leaf mitochondria, rates of O2 uptake with glycine were similar to rates with malate or succinate. It appears that glycine oxidation was coupled to the alternative oxidase to the same extent as malate and succinate oxidation, and the alternative oxidase was not specifically utilized for glycine oxidation. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. RP GOYAL, A (reprint author), MICHIGAN STATE UNIV,DEPT BIOCHEM,E LANSING,MI 48824, USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU JAPANESE SOC PLANT PHYSIOLOGISTS PI KYOTO PA SHIMOTACHIURI OGAWA HIGASHI KAMIKYOKU, KYOTO 602, JAPAN SN 0032-0781 J9 PLANT CELL PHYSIOL JI Plant Cell Physiol. PD MAR PY 1991 VL 32 IS 2 BP 247 EP 251 PG 5 WC Plant Sciences; Cell Biology SC Plant Sciences; Cell Biology GA FD671 UT WOS:A1991FD67100013 ER PT J AU OSULLIVAN, E KAVANAGH, JA AF OSULLIVAN, E KAVANAGH, JA TI CHARACTERISTICS AND PATHOGENICITY OF ISOLATES OF RHIZOCTONIA SPP ASSOCIATED WITH DAMPING-OFF OF SUGAR-BEET SO PLANT PATHOLOGY LA English DT Article ID ANASTOMOSIS GROUPS; CERATOBASIDIUM-CORNIGERUM; SOLANI; FUNGI; CEREALIS; WHEAT AB Rhizoctonia solani and R. cerealis were isolated from diseased sugar-beet seedlings in Ireland. Isolates of R. solani were assigned to anastomosis groups AG-2, AG-4, AG-5 and an unidentified group that did not anastomose with recognized tester isolates. Cultures of AG-2 were similar to those of AG-5 on oatmeal agar (OA) and potato-dextrose-marmite agar (PDMA). Cultures of AG-4, the unidentified group and R. cerealis were morphologically distinct from one another, AG-2 and AG-5. The optimum temperature for growth of AG-2 was 22.5-degrees-C, with optimum growth of AG-4, AG-5 and the unidentified group at 27.5-degrees-C. R. cerealis grew slower than all groups of R. solani, with optimum growth at 22.5-degrees-C. Hyphae of R. cerealis were significantly narrower than those of the groups of R. solani studied. In glasshouse pathogenicity tests, some AG-2 and all AG-4, AG-5 and isolates from the unidentified group caused damping-off of beet seedlings. In controlled environments of 10-25-degrees-C, an AG-2 isolate was the most aggressive at 10-degrees-C whilst AG-4, AG-5 and the unidentified group caused most disease at or above 15-degrees-C. R. cerealis was also pathogenic to beet seedlings, causing damping-off at 10 and 15-degrees-C. C1 NATL UNIV IRELAND UNIV COLL DUBLIN,DEPT PLANT PATHOL,DUBLIN 4,IRELAND. RP OSULLIVAN, E (reprint author), OAK PK RES CTR,DEPT PLANT PATHOL ENTOMOL,CARLOW,IRELAND. NR 25 TC 14 Z9 14 U1 3 U2 8 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0032-0862 J9 PLANT PATHOL JI Plant Pathol. PD MAR PY 1991 VL 40 IS 1 BP 128 EP 135 DI 10.1111/j.1365-3059.1991.tb02301.x PG 8 WC Agronomy; Plant Sciences SC Agriculture; Plant Sciences GA FC149 UT WOS:A1991FC14900016 ER PT J AU LEUTERER, F SOLDNER, F BRAMBILLA, M MUNICH, M MONACO, F ZOUHAR, M BARTIROMO, R TUCCILLO, A BERNABEI, S FOREST, C AF LEUTERER, F SOLDNER, F BRAMBILLA, M MUNICH, M MONACO, F ZOUHAR, M BARTIROMO, R TUCCILLO, A BERNABEI, S FOREST, C TI COUPLING OF THE 2X24 WAVE-GUIDE GRILL FOR LOWER HYBRID WAVES IN ASDEX SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article AB Experimental results on the coupling of a 2 x 24 waveguide grill are compared with theory. Graphite tiles attached directly to the grill and intended to protect the grill against particle bombardment have been found to degrade the coupling substantially if they protrude only a few millimeters beyond the actual grill surface. Measurements in this case are compatible with calculations where a vacuum gap is introduced between the grill and the plasma. Low reflection is obtained when the tiles do not protrude. Coupling can be maintained when the r.f. pulse is started while the plasma is near to the grill and then moved to a larger grill-separatrix distance where otherwise total reflection would occur. C1 ENEA ASSOC,EURATOM,I-00044 FRASCATI,ITALY. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP LEUTERER, F (reprint author), EURATOM IPP ASSOC,MAX PLANCK INST PLASMAPHYS,W-8046 GARCHING,GERMANY. NR 15 TC 34 Z9 34 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1991 VL 33 IS 3 BP 169 EP 180 DI 10.1088/0741-3335/33/3/001 PG 12 WC Physics, Fluids & Plasmas SC Physics GA FD039 UT WOS:A1991FD03900001 ER PT J AU MAZZUCATO, E NAZIKIAN, R AF MAZZUCATO, E NAZIKIAN, R TI MICROWAVE REFLECTOMETRY FOR THE STUDY OF DENSITY-FLUCTUATIONS IN TOKAMAK PLASMAS SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article AB The effect of small scale density fluctuations on the propagation of electromagnetic waves in an inhomogeneous magnetized plasma in the presence of a cut-off is investigated. It is shown that, provided the fluctuation scale length is greater than the free space wavelength of an incident plane wave, the scattered field is strongly enhanced from fluctuations near the turning point. Numerical results for wave propagation in a Tokamak plasma demonstrate the feasibility of reflectometry for the localized measurement of density fluctuations in the range k perpendicular-to-rho-i << 1. RP MAZZUCATO, E (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,JAMES FORRESTAL CAMPUS,POB 451,PRINCETON,NJ 08543, USA. NR 9 TC 74 Z9 75 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1991 VL 33 IS 3 BP 261 EP 274 DI 10.1088/0741-3335/33/3/009 PG 14 WC Physics, Fluids & Plasmas SC Physics GA FD039 UT WOS:A1991FD03900009 ER PT J AU FELDMAN, DL MANN, D AF FELDMAN, DL MANN, D TI POLICY ANALYSIS AND THE MANAGEMENT OF CLIMATE CHANGE - INSTITUTIONAL ADAPTABILITY IN THE FACE OF SCIENTIFIC UNCERTAINTY SO POLICY STUDIES JOURNAL LA English DT Article C1 UNIV CALIF SANTA BARBARA,POLIT SCI,SANTA BARBARA,CA 93106. RP FELDMAN, DL (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37830, USA. NR 15 TC 3 Z9 3 U1 2 U2 2 PU POLICY STUDIES ORGANIZATION PI URBANA PA UNIV ILLINOIS 361 LINCOLN HALL, URBANA, IL 61801 SN 0190-292X J9 POLICY STUD J JI Policy Stud. J. PD SPR PY 1991 VL 19 IS 2 BP 43 EP 49 DI 10.1111/j.1541-0072.1991.tb01880.x PG 7 WC Political Science; Public Administration SC Government & Law; Public Administration GA GD308 UT WOS:A1991GD30800003 ER PT J AU DOWLEY, LJ OSULLIVAN, E AF DOWLEY, LJ OSULLIVAN, E TI CHANGES IN THE DISTRIBUTION OF PHENYLAMIDE-RESISTANT STRAINS OF PHYTOPHTHORA-INFESTANS (MONT) DEBARY IN IRELAND 1985-89 SO POTATO RESEARCH LA English DT Article DE METALAXYL; FLOATING DISK; SOLANUM-TUBEROSUM L ID POTATO FIELDS AB Phenylamide-based fungicides were reintroduced to the Irish market in 1985. Mixtures of phenylamides and mancozeb were recommended for no more than 3 sprays in potato late blight control programmes with the last systemic spray to be applied not later than 31 July. Samples of potato foliage infected with P infestans were collected from the main potato growing areas in Ireland over a five-year period starting in 1985. Using the floating disc method, 11 % of the crops sampled in 1985 were found to have phenylamide-resistant strains of P infestans present. The number of crops with resistant strains increased rapidly up to 1988 when 83 % of the crops sampled had resistance. Factors affecting the distribution of resistance and the efficacy of a phenylamide-based spray programme are discussed. C1 PLANT PATHOL & ENTOMOL DEPT,OAK PK RES CTR,CARLOW,IRELAND. NR 5 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN ASSN POTATO RES PI WAGENINGEN PA POSTBUS 20, 6700 WAGENINGEN, NETHERLANDS SN 0014-3065 J9 POTATO RES JI Potato Res. PD MAR PY 1991 VL 34 IS 1 BP 67 EP 69 DI 10.1007/BF02358096 PG 3 WC Agronomy SC Agriculture GA KN522 UT WOS:A1991KN52200008 ER PT J AU WOODRUFF, WH EINARSDOTTIR, O DYER, RB BAGLEY, KA PALMER, G ATHERTON, SJ GOLDBECK, RA DAWES, TD KLIGER, DS AF WOODRUFF, WH EINARSDOTTIR, O DYER, RB BAGLEY, KA PALMER, G ATHERTON, SJ GOLDBECK, RA DAWES, TD KLIGER, DS TI NATURE AND FUNCTIONAL IMPLICATIONS OF THE CYTOCHROME-A3 TRANSIENTS AFTER PHOTODISSOCIATION OF CO-CYTOCHROME OXIDASE SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE TIME-RESOLVED SPECTROSCOPY; HEME AND COPPER LIGATION; LIGAND SHUTTLE; PROTON TRANSLOCATION ID MAGNETIC CIRCULAR-DICHROISM; BINDING; SPECTROSCOPY; TEMPERATURE; DERIVATIVES; HEMOGLOBIN; PHOTOLYSIS; PORPHYRINS; HEMES AB Time-resolved electronic absorption, infrared, resonance Raman, and magnetic circular dichroism spectroscopies are applied to characterization of the intermediate that is formed within 20 ps after photodissociation of CO from cytochrome alpha-3 in reduced cytochrome oxidase. This intermediate decays with the same half-life (almost-equal-to 1-mu-s) as the post-photodissociation Cu(B)+-CO species previously observed by time-resolved infrared. The transient UV/visible spectra, kinetics, infrared, and Raman evidence suggest that an endogenous ligand is transferred from Cu(B) to Fe(a3) when CO binds to Cu(B), forming a cytochrome alpha-3 species with axial ligation that differs from the reduced unliganded enzyme. The time-resolved magnetic circular dichroism results suggest that this transient is high-spin and, therefore, five-coordinate. Thus we infer that the ligand from Cu(B) binds on the distal side of cytochrome alpha-3 and displaces the proximal histidine imidazole. This remarkable mechanistic feature is an additional aspect of the previously proposed "ligand-shuttle" activity of the Cu(B)/Fe(a3) pair. We speculate as to the identity of the ligand that is transferred between Cu(B) and Fe(a3) and suggest that the ligand shuttle may play a functional role in redox-linked proton translocation by the enzyme. C1 UNIV TEXAS,CTR FAST KINET RES,AUSTIN,TX 78712. UNIV CALIF SANTA CRUZ,DEPT CHEM,SANTA CRUZ,CA 95064. RICE UNIV,DEPT BIOCHEM,HOUSTON,TX 77251. RP WOODRUFF, WH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,INC4,MAIL STOP C345,LOS ALAMOS,NM 87545, USA. FU NIDDK NIH HHS [DK 36263]; NIGMS NIH HHS [GM 38549, GM 21337] NR 35 TC 129 Z9 129 U1 0 U2 1 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 MAR PY 1991 VL 88 IS 6 BP 2588 EP 2592 DI 10.1073/pnas.88.6.2588 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FC216 UT WOS:A1991FC21600116 PM 1848709 ER PT J AU KIMURA, M KOWARI, KI INOKUTI, M BRONIC, IK SRDOC, D OBELIC, B AF KIMURA, M KOWARI, KI INOKUTI, M BRONIC, IK SRDOC, D OBELIC, B TI THEORETICAL-STUDY OF W VALUES IN HYDROCARBON GASES SO RADIATION RESEARCH LA English DT Article ID 100 KEV ELECTRONS; SECONDARY ELECTRONS; IONIZATION; MOLECULES; DEGRADATION; EXCITATION; WATER C1 RICE UNIV, DEPT PHYS, HOUSTON, TX 77251 USA. RUDJER BOSKOVIC INST, YU-41000 ZAGREB, YUGOSLAVIA. RP ARGONNE NATL LAB, ARGONNE, IL 60439 USA. NR 27 TC 14 Z9 14 U1 0 U2 0 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 EI 1938-5404 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1991 VL 125 IS 3 BP 237 EP 242 DI 10.2307/3578104 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA FB507 UT WOS:A1991FB50700001 PM 2000446 ER PT J AU ROOTS, R HENLE, E HOLLEY, WR CHATTERJEE, A AF ROOTS, R HENLE, E HOLLEY, WR CHATTERJEE, A TI MEASUREMENTS OF NUCLEIC BASES RELEASED AFTER GAMMA-IRRADIATION OF DNA IN SOLUTION IN AIR SO RADIATION RESEARCH LA English DT Article ID ESCHERICHIA-COLI DNA; STRAND BREAKS; AQUEOUS-SOLUTION; RADIATION C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. NR 18 TC 13 Z9 13 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 MAR PY 1991 VL 125 IS 3 BP 288 EP 292 DI 10.2307/3578112 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA FB507 UT WOS:A1991FB50700009 PM 1848021 ER PT J AU RILEY, EF LINDGREN, AL ANDERSEN, AL MILLER, RC AINSWORTH, EJ AF RILEY, EF LINDGREN, AL ANDERSEN, AL MILLER, RC AINSWORTH, EJ TI RELATIVE CATARACTOGENIC EFFECTS OF X-RAYS, FISSION-SPECTRUM NEUTRONS, AND FE-56 PARTICLES - A COMPARISON WITH MITOTIC EFFECTS SO RADIATION RESEARCH LA English DT Article ID ACCELERATED HEAVY-PARTICLES; LENS; MICE; IRRADIATION; RADIATION; ARGON; CELLS; IONS C1 BEMIDJI STATE UNIV,DEPT BIOL,BEMIDJI,MN 56601. UNIV IOWA,RADIAT RES LAB,IOWA CITY,IA 52242. COLUMBIA UNIV,CTR RADIOL RES,NEW YORK,NY 10032. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 22 TC 16 Z9 16 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 MAR PY 1991 VL 125 IS 3 BP 298 EP 305 DI 10.2307/3578114 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA FB507 UT WOS:A1991FB50700011 PM 2000454 ER PT J AU STRAUME, T AF STRAUME, T TI DOBSON,ROBERT,LOWRY (1919-1990) - IN MEMORIAM SO RADIATION RESEARCH LA English DT Item About an Individual RP STRAUME, T (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, 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 MAR PY 1991 VL 125 IS 3 BP 350 EP 351 PG 2 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA FB507 UT WOS:A1991FB50700022 ER PT J AU LOO, JA LOO, RRO UDSETH, HR EDMONDS, CG SMITH, RD AF LOO, JA LOO, RRO UDSETH, HR EDMONDS, CG SMITH, RD TI SOLVENT-INDUCED CONFORMATIONAL-CHANGES OF POLYPEPTIDES PROBED BY ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY SO RAPID COMMUNICATIONS IN MASS SPECTROMETRY LA English DT Article ID UBIQUITIN; PROTEINS AB Electrospray-ionization (ESI) mass spectrometry is used to monitor higher order structural changes of polypeptides induced by alteration of the pH or organic solvent composition in the protein solution environment. A bimodal charge-state distribution is observed in the ESI mass spectrum of ubiquitin (relative molecular mass 8565) in solutions containing small amounts (< 20%) of organic solvents. The distribution of peaks at high m/z (low-charge state) is found to represent the protein in its native, globular state; the higher-charge-state distribution is characteristic for a more extended conformation. Addition of methanol denaturant in excess of 40% v/v is needed to eliminate the low-charge-state distribution completely. Lesser amounts of acetonitrile, acetone, or isopropanol (approximately 20%) are required to denature the unibquitin protein. Other proteins showing conformational effects in their ESI mass spectra are also illustrated. While the ESI spectra are related to solution phase structure, ESI-tandem mass spectrometry of multiply charged molecular ions of different conformation is suggested as a probe of gas-phase protein three-dimensional structure. 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 FU NHGRI NIH HHS [HG 00327] NR 27 TC 251 Z9 252 U1 7 U2 39 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 MAR PY 1991 VL 5 IS 3 BP 101 EP 105 DI 10.1002/rcm.1290050303 PG 5 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA FC135 UT WOS:A1991FC13500002 PM 1666527 ER PT J AU NIETSCHMANN, B AF NIETSCHMANN, B TI MISKITO COAST PROTECTED AREA SO RESEARCH & EXPLORATION LA English DT Note C1 LAWRENCE BERKELEY LAB,DEPT GEOG,BERKELEY,CA 94720. NR 0 TC 2 Z9 2 U1 1 U2 3 PU NATL GEOGRAPHIC SOC PI WASHINGTON PA 17TH AND M STS NW, WASHINGTON, DC 20036 SN 8755-724X J9 RES EXPLOR JI Res. Explor. PD SPR PY 1991 VL 7 IS 2 BP 232 EP 234 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LE778 UT WOS:A1991LE77800010 ER PT J AU PICCARD, RD VO-DINH, T AF PICCARD, RD VO-DINH, T TI A MULTI-OPTICAL-FIBER ARRAY WITH CHARGE-COUPLED DEVICE IMAGE DETECTION FOR PARALLEL PROCESSING OF LIGHT SIGNALS AND SPECTRA SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SPECTROSCOPY AB We describe a new two-dimensional multioptical-fiber array (MOFA) with 144 elements, its use with charge-coupled device (CCD) image detection to perform parallel processing for light intensity measurements, and its use with a concave aspherical grating and CCD image detection to perform parallel processing for spectrometry. Each 2-m fiber extending from the MOFA is individually sheathed in a flexible, opaque cover. The light signals can be measured simultaneously with cross-talk ranging from 0.4% to 0.03% of the peak signal, depending upon configuration. We characterize the instrument in both the intensity and the spectrometric configurations, and present techniques for optimizing performance. C1 OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, ADV MONITORING DEV GRP, OAK RIDGE, TN 37830 USA. OHIO UNIV, UNIV COMP & LEARNING SERV, ATHENS, OH 45701 USA. NR 20 TC 11 Z9 11 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1991 VL 62 IS 3 BP 584 EP 594 DI 10.1063/1.1142110 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EZ923 UT WOS:A1991EZ92300003 ER PT J AU JOYCE, SA HOUSTON, JE AF JOYCE, SA HOUSTON, JE TI A NEW FORCE SENSOR INCORPORATING FORCE-FEEDBACK CONTROL FOR INTERFACIAL FORCE MICROSCOPY SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ATOMIC-SCALE FRICTION; TUNGSTEN TIP; SURFACE AB A new interfacial-force microscope capable of measuring the forces between two surfaces over the entire range of surface separations, up to contact, is described. The design is centered around a differential-capacitance displacement sensor where the common capacitor plate is supported by torsion bars. A force-feedback control system is incorporated which balances the interfacial forces at the sensor, maintaining the common capacitor plate at its rest position. This control therefore eliminates the instability or "jumping" which occurs with conventional cantilever-based force sensors when the attractive force gradient between the fixed sample and sensor exceeds the mechanical stiffness of the cantilever. The operating characteristics of the sensor and its ability to measure interfacial forces using the feedback control at surface separations smaller than this instability point are demonstrated. RP JOYCE, SA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI Joyce, Stephen/Q-7804-2016 OI Joyce, Stephen/0000-0003-1330-7362 NR 26 TC 188 Z9 189 U1 1 U2 29 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 MAR PY 1991 VL 62 IS 3 BP 710 EP 715 DI 10.1063/1.1142072 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EZ923 UT WOS:A1991EZ92300020 ER PT J AU XIE, ZQ LYNEIS, CM LAM, RS LUNDGREN, SA AF XIE, ZQ LYNEIS, CM LAM, RS LUNDGREN, SA TI ENHANCED ECR ION-SOURCE PERFORMANCE WITH AN ELECTRON-GUN SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB An electron gun for the advanced electron cyclotron resonance (AECR) source has been developed to increase the production of high charge state ions. The AECR source, which operates at 14 GHz, is being developed for the 88-in. cyclotron at Lawrence Berkeley Laboratory. The electron gun injects 10 to 150 eV electrons into the plasma chamber of the AECR. With the electron gun the AECR has produced at 10 kV extraction voltage 131 e mu-A of O7+, 13 e mu-A of O8+, 17 e mu-A of Ar14+, 2.2 e mu-A of Kr25+, 1 e mu-A of Xe31+, and 0.2 e mu-A of Bi38+. The AECR was also tested as a single stage source with a coating of SiO2 on the plasma chamber walls. This significantly improved its performance compared to no coating, but direct injection of electrons with the electron gun produced the best results. RP XIE, ZQ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 6 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 MAR PY 1991 VL 62 IS 3 BP 775 EP 778 DI 10.1063/1.1142083 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EZ923 UT WOS:A1991EZ92300031 ER PT J AU MCKONE, TE AF MCKONE, TE TI HUMAN EXPOSURE TO CHEMICALS FROM MULTIPLE MEDIA AND THROUGH MULTIPLE PATHWAYS - RESEARCH OVERVIEW AND COMMENTS SO RISK ANALYSIS LA English DT Editorial Material ID FUGACITY; MODEL RP MCKONE, TE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 5507,L-453,LIVERMORE,CA 94550, USA. NR 23 TC 18 Z9 18 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 MAR PY 1991 VL 11 IS 1 BP 5 EP 10 DI 10.1111/j.1539-6924.1991.tb00556.x PG 6 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA FD081 UT WOS:A1991FD08100001 PM 2038617 ER PT J AU RUSSELL, M AF RUSSELL, M TI CLEANUP OF OLD WASTES - IS SUPERFUND BROKE SO RISK ANALYSIS LA English DT Article C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. RP RUSSELL, M (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. NR 0 TC 1 Z9 1 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 MAR PY 1991 VL 11 IS 1 BP 71 EP 74 DI 10.1111/j.1539-6924.1991.tb00573.x PG 4 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA FD081 UT WOS:A1991FD08100018 ER PT J AU WHITFIELD, RG VANKUIKEN, JC AF WHITFIELD, RG VANKUIKEN, JC TI DETECT SO RISK ANALYSIS LA English DT Article RP WHITFIELD, RG (reprint author), ARGONNE NATL LAB,DIV ENVIRONM ASSESSMENT & INFORMAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, 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 MAR PY 1991 VL 11 IS 1 BP 159 EP 161 DI 10.1111/j.1539-6924.1991.tb00586.x PG 3 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA FD081 UT WOS:A1991FD08100031 ER PT J AU WHITE, RK AF WHITE, RK TI TRANSPORTATION FOR THE NUCLEAR INDUSTRY - WALTON,DG, BLACKBURN,SM SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 1 U2 1 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 MAR PY 1991 VL 11 IS 1 BP 163 EP 163 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 FD081 UT WOS:A1991FD08100032 ER PT J AU WHITE, RK AF WHITE, RK TI METAL SPECIATION - THEORY, ANALYSIS AND APPLICATION - KRAMER,JR, ALLEN,HE SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 1 U2 1 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 MAR PY 1991 VL 11 IS 1 BP 163 EP 164 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 FD081 UT WOS:A1991FD08100034 ER PT J AU WHITE, RK AF WHITE, RK TI REPRODUCTIVE HEALTH-HAZARDS IN THE WORKPLACE - OFF-TECHN-ASS-TASK-FORC SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 1 U2 1 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 MAR PY 1991 VL 11 IS 1 BP 163 EP 163 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 FD081 UT WOS:A1991FD08100033 ER PT J AU WHITE, RK AF WHITE, RK TI THE RISK RANKING TECHNIQUE IN DECISION-MAKING - CHICKEN,JC, HAYNS,MR SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,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 MAR PY 1991 VL 11 IS 1 BP 164 EP 164 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 FD081 UT WOS:A1991FD08100036 ER PT J AU WHITE, RK AF WHITE, RK TI DRINKING-WATER AND HEALTH - SELECTED ISSUES IN RISK ASSESSMENT, VOL 9, - SAF-DRINK-WAT-COMM-BOARD-ENV-STUD-TOX-COMM-LIF-SCI-NAT-RES-COUNC SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,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 MAR PY 1991 VL 11 IS 1 BP 164 EP 165 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 FD081 UT WOS:A1991FD08100037 ER PT J AU WHITE, RK AF WHITE, RK TI ENVIRONMENTAL HAZARDS - COMMUNICATING RISKS AS A SOCIAL-PROCESS - KRIMSKY,S, PLOUGH,A SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,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 MAR PY 1991 VL 11 IS 1 BP 164 EP 164 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 FD081 UT WOS:A1991FD08100035 ER PT J AU WHITE, RK AF WHITE, RK TI FILM BADGE DOSIMETRY IN ATMOSPHERIC NUCLEAR TESTS - COMM-FILM-BADG-DOS-ATM-NUCL-TESTS-NUCL-ENGN-BOARD-COMM-ENGN-TECHN-SYST-N AT-RES-COUNC SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 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 MAR PY 1991 VL 11 IS 1 BP 165 EP 166 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 FD081 UT WOS:A1991FD08100039 ER PT J AU WHITE, RK AF WHITE, RK TI RISK ANALYSIS - A GUIDE TO PRINCIPLES AND METHODS FOR ANALYZING HEALTH AND ENVIRONMENTAL RISKS - COHRSSEN,JJ, COVELLO,VT SO RISK ANALYSIS LA English DT Book Review RP WHITE, RK (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY,OFF RISK ANAL,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 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 MAR PY 1991 VL 11 IS 1 BP 165 EP 165 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 FD081 UT WOS:A1991FD08100038 ER PT J AU RAYMOND, R RENEAU, SL HARRINGTON, CD AF RAYMOND, R RENEAU, SL HARRINGTON, CD TI ELEMENTAL RELATIONSHIPS IN ROCK VARNISH AS SEEN WITH SCANNING ELECTRON-MICROSCOPY AND ENERGY DISPERSIVE-X-RAY ELEMENTAL LINE PROFILING SO SCANNING MICROSCOPY LA English DT Article DE ROCK VARNISH; ELECTRON MICROSCOPY; LINE PROFILING; ENERGY DISPERSIVE ANALYSIS; VARNISH CATION RATIOS; MN-FE RATIOS; BIRNESSITE ID DESERT VARNISH; MANGANESE; PROBE AB The heterogeneous nature of rock varnish requires a through understanding of elemental and mineralogic compositions before chemical variability of rock varnish may be confidently related to varnish age or to past geochemical environments. Elemental relationships in rock varnish were examined using scanning electron microscopy in conjunction with an elemental line profiling routine using semi-quantitative, energy-dispersive x-ray analysis. Results of our analyses suggest: 1) variations in cation concentrations used in varnish cation-ratio dating relate more specifically to variations in detritus concentration within the varnish than to element mobility as defined by weathering indices; 2) Mn:Fe ratios may be a poor indicator of paleoclimatic fluctuations; and 3) the Mn-oxide phase existing in varnish is most likely a Ba-enriched phase rather than birnessite. An examination of data collected from elemental line profiling offers great potential for gaining insights into geochemical processes affecting the deposition and diagenesis of rock varnish and for testing hypotheses relating to its chemical variability. RP RAYMOND, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,GEOL & GEOCHEM GRP,EES-1,MAIL STOP D469,LOS ALAMOS,NM 87545, USA. NR 27 TC 12 Z9 12 U1 0 U2 2 PU SCANNING MICROSCOPY INT PI CHICAGO PA PO BOX 66507, AMF O'HARE, CHICAGO, IL 60666 SN 0891-7035 J9 SCANNING MICROSCOPY JI Scanning Microsc. PD MAR PY 1991 VL 5 IS 1 BP 37 EP 46 PG 10 WC Microscopy SC Microscopy GA FH432 UT WOS:A1991FH43200004 ER PT J AU RENEAU, SL HAGAN, RC HARRINGTON, CD RAYMOND, R AF RENEAU, SL HAGAN, RC HARRINGTON, CD RAYMOND, R TI SCANNING ELECTRON-MICROSCOPIC ANALYSIS OF ROCK VARNISH CHEMISTRY FOR CATION-RATIO DATING - AN EXAMINATION OF ELECTRON-BEAM PENETRATION DEPTHS SO SCANNING MICROSCOPY LA English DT Article DE SCANNING ELECTRON MICROSCOPY; ROCK VARNISH; CATION-RATIO DATING; X-RAY MAPS; X-RAY DEPTH-DISTRIBUTION CURVES AB Rock varnish is a microns-thick manganese- and iron-rich coating that forms on exposed rock surfaces in arid and semi-arid environments, and empirical correlations of the varnish cation ratio (K + Ca):Ti with age have been used to estimate ages of geomorphic surfaces. One method of obtaining varnish chemistry for cation-ratio dating involves scanning electron microscope (SEM) energy dispersive x-ray (EDX) analysis of natural varnish surfaces. The chemical analyses of rock varnish with SEM/EDX utilize a sequence of accelerating voltages to vary penetration depths into the sample. Using elemental x-ray maps of natural varnish surfaces obtained by SEM/EDX analysis, penetration into the substrate can be recognized at accelerating voltages where contamination with substrate is inferred from SEM/EDX chemical analyses, illustrating the ability of the SEM method to obtain varnish chemistry with minimal inclusion of substrate. Calculations of theoretical x-ray depth-distribution (phi(rho-z)) curves in varnish indicate that at an accelerating voltage of 10 kV most of the emitted x-rays are generated in the upper 0.5-mu-m of a sample. At a higher voltage of 30 kV most of the signal is still restricted to the upper 2-mu-m, representing a very small percentage of total varnish volume in many cases. The ability of the SEM method to obtain empirical correlations of the chemistry of the uppermost varnish with varnish age suggests that it is not necessary to average the entire varnish coat, and that surface-biased varnish analyses provide similar results as bulk varnish analyses. RP RENEAU, SL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,MS D462,LOS ALAMOS,NM 87545, USA. NR 9 TC 6 Z9 6 U1 0 U2 2 PU SCANNING MICROSCOPY INT PI CHICAGO PA PO BOX 66507, AMF O'HARE, CHICAGO, IL 60666 SN 0891-7035 J9 SCANNING MICROSCOPY JI Scanning Microsc. PD MAR PY 1991 VL 5 IS 1 BP 47 EP 54 PG 8 WC Microscopy SC Microscopy GA FH432 UT WOS:A1991FH43200005 ER PT J AU HARRINGTON, CD KRIER, DJ RAYMOND, R RENEAU, SL AF HARRINGTON, CD KRIER, DJ RAYMOND, R RENEAU, SL TI BARIUM CONCENTRATION IN ROCK VARNISH - IMPLICATIONS FOR CALIBRATED ROCK VARNISH DATING CURVES SO SCANNING MICROSCOPY LA English DT Article DE ROCK VARNISH; CATION-RATIO DATING; BARIUM; BARIUM-TITANIUM DECOMPOSITION; SOUTHERN NEVADA; SCANNING ELECTRON MICROSCOPY AB Cation-ratio dating of rock varnish is a recently developed technique for obtaining surface exposure ages of a wide variety of geomorphic surfaces. As originally proposed, the technique utilizes a ratio among minor cations [(K + Ca)/Ti] in rock varnish. Although this varnish cation ratio is related to the Ti concentration, it can also be affected by the presence of Ba that may be partially included in the analyzed concentration of Ti. Barium is a minor constituent found in virtually all rock varnishes sampled from the Lake Mead area, Las Vegas Valley, and the Crater Flat region of southern Nevada. Barium is heterogeneously distributed in rock varnish, associated predominantly with Mn and secondarily with sulfur (detrital barite). Barium concentrations are apparently greater in varnishes found on young surfaces (< 100 ka) than in varnishes found on older surfaces (> 500 ka), and they are apparently greater in varnishes on low elevation surfaces than in varnishes on hill-slope or ridge deposits. In energy dispersive spectroscopy (EDS), Ba L-alpha and L-beta peaks overlap with Ti K-alpha and K-beta peaks. Unless decomposed, the overlapping peaks may yield erroneously large values for Ti. We have compared the effect of Ba concentration on calculated varnish cation ratios using: (1) quantitative EDS with the scanning electron microscope (SEM) that decomposes Ti and Ba peaks; (2) quantitative wavelength-dispersive spectroscopy (WDS) with an electron probe microanalyzer (EPM); (3) semi-quantitative EDS with the SEM that decomposes Ti and Ba peaks; and (4) semi-quantitative EDS with the SEM that does not decompose Ti and Ba lines. Results suggest small amounts of Ba relative to Ti will not significantly change the value of the calculated varnish cation ratio with or without decomposition. However, if Ba concentrations are high relative to Ti, the effect on cation ratios is pronounced, resulting in anomalously low cation ratios. As younger varnishes and varnishes on topographically lower surfaces apparently have higher Ba concentrations, the effect of Ba on cation ratios calculated for younger rock varnishes and lower surfaces will be greater. RP HARRINGTON, CD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,MS D462,LOS ALAMOS,NM 87545, USA. NR 10 TC 10 Z9 10 U1 0 U2 1 PU SCANNING MICROSCOPY INT PI CHICAGO PA PO BOX 66507, AMF O'HARE, CHICAGO, IL 60666 SN 0891-7035 J9 SCANNING MICROSCOPY JI Scanning Microsc. PD MAR PY 1991 VL 5 IS 1 BP 55 EP 62 PG 8 WC Microscopy SC Microscopy GA FH432 UT WOS:A1991FH43200006 ER PT J AU LEDERMAN, LM AF LEDERMAN, LM TI THE TEVATRON SO SCIENTIFIC AMERICAN LA English DT Article AB Because it produces antiprotons, accelerates them in a ring using superconducting magnets and smashes them into protons, it is now the world's most powerful source of data on elementary particles. RP LEDERMAN, LM (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 3 TC 5 Z9 5 U1 1 U2 1 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 MAR PY 1991 VL 264 IS 3 BP 48 EP 55 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EY262 UT WOS:A1991EY26200009 ER PT J AU BRIMHALL, JL CHARLOT, LA BRUEMMER, SM AF BRIMHALL, JL CHARLOT, LA BRUEMMER, SM TI PHASE-STABILITY AND COMPOSITIONAL RANGE OF SPUTTE DEPOSITED BE12NB SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID BERYLLIUM RP BRIMHALL, JL (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 8 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 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR PY 1991 VL 25 IS 3 BP 553 EP 558 DI 10.1016/0956-716X(91)90090-N PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EZ877 UT WOS:A1991EZ87700010 ER PT J AU KOIKE, J AF KOIKE, J TI NUCLEATION AND GROWTH OF A BCC FE PHASE DEPOSITED ON A SINGLE-CRYSTAL (001) CU FILM SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article RP KOIKE, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 5 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 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR PY 1991 VL 25 IS 3 BP 663 EP 668 DI 10.1016/0956-716X(91)90111-D PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EZ877 UT WOS:A1991EZ87700031 ER PT J AU BRADLEY, EL EMIGH, RA MORRIS, JW AF BRADLEY, EL EMIGH, RA MORRIS, JW TI SUPERPLASTIC PROPERTIES OF AN AL-2.4MG-1.8LI-0.5SC ALLOY SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID AL-MG ALLOY; ALUMINUM C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. RP BRADLEY, EL (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & ENGN,BERKELEY,CA 94720, USA. NR 18 TC 8 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR PY 1991 VL 25 IS 3 BP 717 EP 721 DI 10.1016/0956-716X(91)90121-G PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EZ877 UT WOS:A1991EZ87700041 ER PT J AU GSCHNEIDNER, KA BEAUDRY, BJ AF GSCHNEIDNER, KA BEAUDRY, BJ TI COMMENTS ON THE PAPER DTA DETERMINATION OF THE TEMPERATURES AND ENTHALPY CHANGES OF THE ALPHA-]BETA AND SOLID-]LIQUID PHASE-TRANSITIONS OF PURE NEODYMIUM SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP GSCHNEIDNER, KA (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 24 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR PY 1991 VL 25 IS 3 BP 745 EP 748 DI 10.1016/0956-716X(91)90126-L PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EZ877 UT WOS:A1991EZ87700046 ER PT J AU ESSINGTON, ME MATTIGOD, SV AF ESSINGTON, ME MATTIGOD, SV TI TRACE-ELEMENT SOLID-PHASE ASSOCIATIONS IN SEWAGE-SLUDGE AND SLUDGE-AMENDED SOIL SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID HEAVY-METALS; ZONAL CENTRIFUGATION; DENSITY GRADIENT; TREATED SOILS; IRON-OXIDES; FLY-ASH; SPECIATION; CLAYS; LEAD; IDENTIFICATION AB A scheme involving the use of particle size, density, and magnetic susceptibility was applied to sewage sludge and sewage-sludge-amended soil to isolate trace-element-bearing solids for identification by x-ray diffraction (XRD) and scanning electron microscopy/energy dispersive x-ray analysis (SEM/EDXRA). The heavy-density (> 2.96 Mg m-3) fractions of the sludge and amended soil contained barite, celestite, lead silicate, lead phosphate, chromium oxide or oxyhydroxide, sphalerite, and chalcopyrite. Vanadium was associated with Ti, Ca, Si, and Fe in amended soil particles, suggesting its occurrence in titanite. The heavy-density fractions also contained trace-element-bearing particles of industrial origin, including Sb, Cr-Fe, Cr-Ni-Fe, Zn-Sn, Cr-Zn-Fe, Sn-Fe-Cu-Zn, Pb-Cr, Pb-Sn, W-Se, and Co-Cr elemental associations. Trace-element-bearing particles contained in the light-density (< 2.10 Mg m-3) fractions of the sludge and sludge-amended soil were similar to those identified in the heavy-density separates. Their presence was apparently due to particle agglomeration with organic matter. The physicochemical particle fractionation scheme was effective in concentrating trace-mineral phases for detection by SEM/EDXRA. However, crystalline trace-element-bearing minerals were not sufficiently concentrated for XRD identification. C1 PACIFIC NW LAB, GEOCHEM SECT, RICHLAND, WA 99352 USA. RP ESSINGTON, ME (reprint author), UNIV TENNESSEE, DEPT PLANT & SOIL SCI, POB 1071, KNOXVILLE, TN 37901 USA. OI Essington, Michael/0000-0003-0658-0424 NR 39 TC 26 Z9 27 U1 0 U2 2 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAR-APR PY 1991 VL 55 IS 2 BP 350 EP 356 PG 7 WC Soil Science SC Agriculture GA FZ632 UT WOS:A1991FZ63200008 ER PT J AU GEE, GW AF GEE, GW TI PARTICLE-SIZE ANALYSIS BY A MODIFIED PIPETTE PROCEDURE - COMMENTS SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Editorial Material RP GEE, GW (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 15 TC 0 Z9 0 U1 1 U2 5 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAR-APR PY 1991 VL 55 IS 2 BP 571 EP 572 PG 2 WC Soil Science SC Agriculture GA FZ632 UT WOS:A1991FZ63200051 ER PT J AU REILLY, S ARASTEH, D SELKOWITZ, S AF REILLY, S ARASTEH, D SELKOWITZ, S TI THERMAL AND OPTICAL ANALYSIS OF SWITCHABLE WINDOW GLAZINGS SO SOLAR ENERGY MATERIALS LA English DT Article AB Glazing materials with variable optical properties (switchable glazings) offer the ultimate in control over the light and energy entering a building. Products of this kind are in their initial stages of development, and guidelines that relate window energy performance to glazing material properties are needed. Though the use of a computer program for calculating window thermal and optical performance parameters, we evaluated (1) the relative performances of three switchable glazings prototypes with differing solar transmittance spectra; (2) the differences between glazings that switch from transmitting to reflecting and those that switch from transmitting to absorbing; and (3) the effects of positioning the switchable glazing in a window. We focused on design conditions for cooling-dominated buildings, since switchable glazings are expected to reduce cooling and lighting loads. We conclude that the differences in thermal performance between absorbing and reflecting switchable glazings can be eliminated through proper placement of the glazing in a window system and through the use of other spectrally selective glazings. RP REILLY, S (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,WINDOWS & DAYLIGHTING GRP MS903111,BERKELEY,CA 94720, USA. NR 18 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-1633 J9 SOL ENERG MATER PD MAR PY 1991 VL 22 IS 1 BP 1 EP 14 DI 10.1016/0165-1633(91)90002-3 PG 14 WC Energy & Fuels; Materials Science, Multidisciplinary SC Energy & Fuels; Materials Science GA FK635 UT WOS:A1991FK63500001 ER PT J AU BURMESTER, CP WILLE, LT GRONSKY, R AF BURMESTER, CP WILLE, LT GRONSKY, R TI MONTE-CARLO STUDY OF DOMAIN FORMATION IN YBA2(CU1-XFEX)3OZ SO SOLID STATE COMMUNICATIONS LA English DT Article ID YBA2CU3O7-DELTA; ORDER; SUBSTITUTION; PEROVSKITE; BEHAVIOR; COPPER; PHASE; FE AB Upon progressive doping with Fe the YBa2(Cu(1-x)Fe(x))3O(z) compound transforms an orthorhombic to a tetragonal structure without an accompanying loss of superconductivity. This behavior has been interpreted by assuming that the tetragonal structure consists of many conflicting orthorhombic microdomains pinned by the Fe-atoms. Extending an Ising model previously used to model the undoped compound, we show by Monte Carlo simulation that such microdomains do indeed occur. The oxygen content is allowed to vary in the simulations, while the Fe-Cu sublattice is handled in the canonical ensemble (fixed Fe-content). The Fe-atoms are mobile and found to cluster along the < 11 > direction in precise agreement with experimental observations. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP BURMESTER, CP (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 21 TC 11 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAR PY 1991 VL 77 IS 9 BP 693 EP 697 DI 10.1016/0038-1098(91)90771-M PG 5 WC Physics, Condensed Matter SC Physics GA FA167 UT WOS:A1991FA16700014 ER PT J AU BRAATEN, NA BORG, A GREPSTAD, JK RAAEN, S RUCKMAN, MW AF BRAATEN, NA BORG, A GREPSTAD, JK RAAEN, S RUCKMAN, MW TI OXYGEN-K NEAR-EDGE-STRUCTURE FOR THIN CE OXIDE-FILMS SO SOLID STATE COMMUNICATIONS LA English DT Article ID STATE; 3D AB Oxygen K-edge absorption studies are performed on thin oxidized Ce films on Ta substrates. The various absorption edges are identified as belonging to trivalent or tetravalent Ce oxides by use of previous photoemission results, and by use of the O K-edge absorption spectrum from formally tetravalent CeO2, which is obtained by oxidizing a thick Ce film. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. RP BRAATEN, NA (reprint author), UNIV TRONDHEIM,N-7034 TRONDHEIM,NORWAY. NR 10 TC 6 Z9 6 U1 0 U2 4 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 MAR PY 1991 VL 77 IS 9 BP 731 EP 734 DI 10.1016/0038-1098(91)90778-T PG 4 WC Physics, Condensed Matter SC Physics GA FA167 UT WOS:A1991FA16700021 ER PT J AU WEIR, ST AF WEIR, ST TI NONLINEAR FLUX-PINNING ENERGIES VERSUS CURRENT DENSITIES IN HIGH-TC SUPERCONDUCTORS - IMPLICATIONS FOR UOS DERIVED FROM MAGNETIC-RELAXATION EXPERIMENTS SO SOLID STATE COMMUNICATIONS LA English DT Article ID CREEP AB Magnetic relaxation rate measurements of high-T(c) superconductors in the critical state are often used to determine the characteristic flux-pinning energies of these materials. The relaxation-rate equations used to obtain flux-pinning energies usually assume a linear U vs. J dependence. Recent studies of the flux pinning properties of high-T(c) materials, however, show that the U vs. J relation is highly non-linear, the relation being more accurately described by a power-law or logarithmic function than a linear one. It is shown here that for a power-law U vs. J dependence, the U(o) derived from a magnetic relaxation experiment is a closer measure of U(J = J(c)) than of U(J almost-equal-to O). As a result, for a power-law U vs. J dependence U(o) is not an accurate measure of the absolute depth of the flux-pinning potential, as is commonly assumed. RP WEIR, ST (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. RI Weir, Samuel/H-5046-2012 NR 17 TC 11 Z9 11 U1 0 U2 0 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 MAR PY 1991 VL 77 IS 11 BP 839 EP 841 DI 10.1016/0038-1098(91)90816-E PG 3 WC Physics, Condensed Matter SC Physics GA FB636 UT WOS:A1991FB63600005 ER PT J AU WEINRACH, JB HAWLEY, M SATTELBERGER, AP SWANSON, BI AF WEINRACH, JB HAWLEY, M SATTELBERGER, AP SWANSON, BI TI SCANNING TUNNELING MICROSCOPY (STM) STUDIES OF QUASI-ONE-DIMENSIONAL MATERIALS - K4[PT2(P2O5H2)4BR]-3H2O SO SOLID STATE COMMUNICATIONS LA English DT Article ID TETRAPERCHLORATE; PLATINUM; PERCHLORATE; COMPOUND; SALT AB Scanning tunneling microscopy images were collected for the trapped-valent linear-chain semiconductor K4[Pt4(P2O5H2)4Br].3H2O at room temperature. Superstructure resulting in the quadrupling of the unit cell is observed parallel to the chain axis. A long (non-2k(f)) period charge-density-wave superstructure (ca. 10 lattice constant spacings) is observed along the chain axis. Regions of crystal dislocations are also observed. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP WEINRACH, JB (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPES & NUCL CHEM,LOS ALAMOS,NM 87545, USA. 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 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAR PY 1991 VL 77 IS 11 BP 853 EP 858 DI 10.1016/0038-1098(91)90819-H PG 6 WC Physics, Condensed Matter SC Physics GA FB636 UT WOS:A1991FB63600008 ER PT J AU FLENSBERG, K FROTA, HO AF FLENSBERG, K FROTA, HO TI CHARGING EFFECTS IN TUNNEL-JUNCTIONS - A 4 LEVEL STUDY SO SOLID STATE COMMUNICATIONS LA English DT Article ID COULOMB BLOCKADE; QUANTUM DYNAMICS; ULTRASMALL AB Charging effects in small tunnel junctions are studied via a transformation which, following Wilson, allows us to treat the hybridization between the two sides and the charging energy exactly. The two conduction bands are transformed to the so-called "hopping" Hamiltonian. The transformation makes the model suitable for a full renormalization group calculation. Here we study a simplified version of this Hamiltonian. We keep only the first term that hybridize directly the two bands and which involves the charging energy and the junction coupling strength. The resulting four level system is solved exactly and the eigenvalues, the mean-square charge difference, and the charge transfer fluctuations are calculated. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP FLENSBERG, K (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. RI Flensberg, Karsten/N-4718-2014 OI Flensberg, Karsten/0000-0002-8311-0103 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 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAR PY 1991 VL 77 IS 12 BP 917 EP 921 DI 10.1016/0038-1098(91)90346-W PG 5 WC Physics, Condensed Matter SC Physics GA FC622 UT WOS:A1991FC62200005 ER PT J AU TRASK, BJ VANDENENGH, G CHRISTENSEN, M MASSA, HF GRAY, JW VANDILLA, M AF TRASK, BJ VANDENENGH, G CHRISTENSEN, M MASSA, HF GRAY, JW VANDILLA, M TI CHARACTERIZATION OF SOMATIC-CELL HYBRIDS BY BIVARIATE FLOW KARYOTYPING AND FLUORESCENCE INSITU HYBRIDIZATION SO SOMATIC CELL AND MOLECULAR GENETICS LA English DT Article ID HUMAN-CHROMOSOMES; MICROCELL FUSION; DNA LIBRARIES; GENE; CONSTRUCTION; COMPLEMENTATION; IDENTIFICATION; ORGANIZATION; ASSIGNMENT; CYTOMETRY AB We report on the use of flow karyotyping and fluorescence in situ hybridization (FISH) to characterize the human chromosomes in somatic cell hybrids. The identity, DNA content, and relative frequency of human chromosomes are derived from flow karyotypes, i.e., measurements of Hoechst and chromomycin fluorescence intensities of chromosomes by dual beam flow cytometry. Chromosome integrity is assessed by comparing the peak position of a human chromosome in the flow karyotypes of a hybrid cell line and its human donor. When human donor cells are unavailable, the peak position of a human chromosome in a hybrid line is compared to the range of peak positions among normal individuals. The relative frequency of human chromosomes in subclones or hybrids grown in culture is monitored using the volumes of peaks in flow karyotypes. FISH with biotinylated human genomic DNA or chromosome-specific repeat sequences as probe is used in conjunction with flow karyotyping to confirm the number of human chromosomes in hybrids. Some small rearrangements are detected by flow karyotyping and not by FISH. On the other hand, translocations between human and rodent chromosomes are detected by FISH and not always by flow karyotyping. Flow karyotyping and FISH were used to characterize over 100 hybrid lines donated by other laboratories. A hybrid set useful for the construction of chromosome-enriched gene libraries is presented. In this set, each of the 24 human chromosome types is present and intact, as judged by these techniques, in a line containing little or no other human material. RP TRASK, BJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,POB 5507 L-452,LIVERMORE,CA 94550, USA. FU NICHD NIH HHS [HD-17665] NR 56 TC 40 Z9 40 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0740-7750 J9 SOMAT CELL MOLEC GEN JI Somat.Cell Mol.Genet. PD MAR PY 1991 VL 17 IS 2 BP 117 EP 136 DI 10.1007/BF01232970 PG 20 WC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity GA FD594 UT WOS:A1991FD59400002 PM 2011792 ER PT J AU POWERS, JM SOMORJAI, GA AF POWERS, JM SOMORJAI, GA TI THE SURFACE OXIDATION OF ALPHA-SILICON CARBIDE BY O-2 FROM 300-K TO 1373-K SO SURFACE SCIENCE LA English DT Article ID ELECTRON; SIC(0001); LEED AB Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS) were used to investigate the oxidation of single crystal alpha-SiC over a wide temperature and O2 pressure range. In ultra-high vacuum, the surface composition of alpha-SiC (0001BAR) as a function of temperature changes due to oxide formation and the sublimation of SiO and Si, yielding graphitic surface carbon. From 300 to 833 K, exposure of Ar+ bombarded alpha-SiC to 10(-8) Torr O2 results in a two-stage oxidation process which yields a submonolayer oxide. Highly disordered alpha-SiC surfaces were found to oxidize faster and more extensively than well-annealed, ordered surfaces. Exposure of the alpha-SiC{0001} surfaces to 1 atm O2 resulted in the production of SiO2 overlayers, which were examined using XPS and Scanning AES (SAES). In these experiments the (0001BAR) surface produced thicker SiO2 overlayers than the (0001) surface. However, the difference in oxide thickness between the two {0001} surfaces was not as dramatic as previously reported and varied from sample to sample. Carbon was not detected in the surface SiO2 layers formed between 973 and 1373 K, which suggested carbon was removed as CO and/or CO2 during the SiC oxidation process. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP POWERS, JM (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,CTR ADV MAT,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 19 TC 56 Z9 56 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR PY 1991 VL 244 IS 1-2 BP 39 EP 50 DI 10.1016/0039-6028(91)90167-Q PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FD545 UT WOS:A1991FD54500010 ER PT J AU HOUSTON, JE ONEILL, DG GOMER, R AF HOUSTON, JE ONEILL, DG GOMER, R TI AN EELS STUDY OF CU ADSORBED ON O/W(110) AND CO/W(110) SO SURFACE SCIENCE LA English DT Article ID OXYGEN; W(110); TUNGSTEN; CU(111); CO AB The vibrational properties of 1 monolayer of Cu adsorbed on O/W(110), Cu1/O/W(110), O/Cu1/W(110) and Cu1-1.5/CO/W(110) were studied at 90 K and on heating to see if the existence of sandwich structures and the electric shielding by single metal layers suggested by previous work [N. Shamir, J.C. Lin and R. Gomer, J. Chem. Phys. 90 (1989) 5135] could be confirmed. It was found that a monolayer of Cu screens the O-W dipole moment effectively while 1.5 Cu monolayers were required for CO on W, probably because in that case a continuous Cu layer is not formed. It was also found that heating Cu1/O/W(110) and O/Cu1W(110) layers gave results which support previous findings on O-Cu segregation [J.S. Lin, N. Shamir and R. Gomer, Surf. Sci. 206 (1988) 206]. C1 UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. RP HOUSTON, JE (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 11 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR PY 1991 VL 244 IS 3 BP 221 EP 227 DI 10.1016/0039-6028(91)90495-E PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FF185 UT WOS:A1991FF18500014 ER PT J AU CHEN, SP VOTER, AF AF CHEN, SP VOTER, AF TI RECONSTRUCTION OF THE (310), (210) AND (110) SURFACES IN FCC METALS SO SURFACE SCIENCE LA English DT Letter ID EMBEDDED-ATOM-METHOD; PHASE-TRANSITION; LATTICE-RELAXATION; GRAIN-BOUNDARIES; AU(110); MODEL; NI; AU; SIMULATION; ALLOYS AB We have investigated the 1 x 2 missing-row reconstruction for the (310), (210), and (110) surfaces of Ni, Pd, Pt, Cu, Ag, Au, and Al using embedded atom potentials. The embedded method (EAM) predicts that on the (310) and (110) surfaces, only Au and Pt reconstruct, but that all seven metals reconstruct on the (210) face. We also introduce a simple model, based on the second moment of the missing bond distribution, that predicts 1 x 2 and possibly higher-order reconstruction for all (210) surfaces and for (110) and (310) surfaces of metals with a large Cauchy pressure (C-12 - C44). On the (110) surfaces, the EAM and the simple model predictions agree with experiment, but not on the (210) surface in the one case studied. RP CHEN, SP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 41 TC 54 Z9 54 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR PY 1991 VL 244 IS 1-2 BP L107 EP L112 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FD545 UT WOS:A1991FD54500005 ER PT J AU MAIN, MV FRITZ, JS AF MAIN, MV FRITZ, JS TI DETERMINATION OF METAL-IONS BY LIQUID-CHROMATOGRAPHIC SEPARATION OF THEIR 2-ACETYLPYRIDINE-4-ETHYL-3-THIOSEMICARBAZONE CHELATES SO TALANTA LA English DT Article ID ANTI-MALARIAL AGENTS; PICOLINE-2-ALDEHYDE THIOSEMICARBAZONE; 2-ACETYLPYRIDINE THIOSEMICARBAZONES; COMPLEXES AB A new thiosemicarbazone was prepared, characterized, and used as a complexing reagent for the chromatographic separation and determination of metal complexes by reverse-phase HPLC. The reagent was sufficiently soluble in methanol-water solutions for metal ions to be complexed in this aqueous organic phase, without need for extraction. Many variables affected the retention times of the metal complexes. Several metals were determined selectively by complexation with the reagent and chromatographic separation of the complexes. Interference effects from other metal ions were also investigated. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 22 TC 15 Z9 16 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-9140 J9 TALANTA JI Talanta PD MAR PY 1991 VL 38 IS 3 BP 253 EP 258 DI 10.1016/0039-9140(91)80044-Z PG 6 WC Chemistry, Analytical SC Chemistry GA FD455 UT WOS:A1991FD45500003 PM 18965137 ER PT J AU KONDOLF, GM CADA, GF SALE, MJ FELANDO, T AF KONDOLF, GM CADA, GF SALE, MJ FELANDO, T TI DISTRIBUTION AND STABILITY OF POTENTIAL SALMONID SPAWNING GRAVELS IN STEEP BOULDER-BED STREAMS OF THE EASTERN SIERRA-NEVADA SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID BROWN TROUT; CHANNEL AB High-gradient boulder-bed streams have been the sites of relatively few studies of salmonid spawning habitat, although they have geomorphic and hydraulic characteristics-and therefore gravel distributions-that are quite different from the more commonly described lower-gradient channels. We documented gravel distribution in seven high-gradient stream reaches in the eastern Sierra Nevada. Gravels occurred only in locations characterized by relatively low shear stress; they formed small pockets in sites of flow divergence and larger deposits upstream of natural hydraulic controls. In 1986 (a wet year), all tracer gravels placed in gravel pockets at nine sites on four streams were completely swept away, and substantial scour, fill, and other channel changes occurred at many sites. In 1987 (a dry year), tracer gravels and the channel cross sections were generally stable. Periodic mobility of gravel may explain why brown trout Salmo trutta are more abundant than rainbow trout Oncorhynchus mykiss in the study reaches, where high flows occur every May and June during snowmelt. Brown trout are fall spawners, and their fry emerge long before the high snowmelt flows, whereas rainbow trout are spring spawners whose eggs are in the gravel, and thus vulnerable to scour, during snowmelt flows. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. INYO NATL FOREST,BISHOP,CA 93514. WHITE MT RES STN,BISHOP,CA 93514. RP KONDOLF, GM (reprint author), UNIV CALIF BERKELEY,DEPT LANDSCAPE ARCHITECTURE,BERKELEY,CA 94720, USA. NR 24 TC 37 Z9 38 U1 3 U2 6 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAR PY 1991 VL 120 IS 2 BP 177 EP 186 DI 10.1577/1548-8659(1991)120<0177:DASOPS>2.3.CO;2 PG 10 WC Fisheries SC Fisheries GA FR516 UT WOS:A1991FR51600005 ER PT J AU SHAMSAI, A NARASIMHAN, TN AF SHAMSAI, A NARASIMHAN, TN TI A NUMERICAL INVESTIGATION OF FREE SURFACE-SEEPAGE FACE RELATIONSHIP UNDER STEADY-STATE FLOW CONDITIONS SO WATER RESOURCES RESEARCH LA English DT Article ID SATURATED-UNSATURATED FLOW; DEFORMABLE POROUS-MEDIA; MODEL AB The relationship between free surface and seepage face under steady conditions of flow has been analyzed for radial and planar flow configurations. The numerical studies, carried out with a saturated-unsaturated flow model, included the simulation of a series of experimental observations documented by Hall (1955). The numerical analysis took into consideration effects of capillary fringe, model geometry, as well as converging and diverging patterns of flow. For the control series of three cases studied, discharge rates, free surface location, seepage face height and the spatial distribution of potentials closely matched the experimental observations. Additional parametric studies showed that converging patterns of flow favor more pronounced development of seepage face than divergent flows. In two-dimensional planar flow, larger drawdowns tend to favor relatively more pronounced development of seepage face. Comparison of the detailed simulation results (taking unsaturated flow into consideration) with results generated using Dupuit-Forchheimer assumptions suggest that the latter may provide discharge estimates that are in error by 12 to 20% both for radial and for two-dimensional planar flows. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DIV EARTH SCI, BERKELEY, CA 94720 USA. RP SHARIF UNIV TECHNOL, DEPT CIVIL ENGN, TEHRAN, IRAN. NR 22 TC 22 Z9 22 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 EI 1944-7973 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1991 VL 27 IS 3 BP 409 EP 421 DI 10.1029/90WR01905 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA FA001 UT WOS:A1991FA00100015 ER PT J AU HICKEN, GK GIEDT, WH BENTLEY, AE AF HICKEN, GK GIEDT, WH BENTLEY, AE TI CORRELATION OF JOINT PENETRATION WITH ELECTRON-BEAM CURRENT DISTRIBUTION SO WELDING JOURNAL LA English DT Article DE EB WELD PENETRATION; ELECTRON BEAM WELDING; EB CURRENT DISTRIBUTION; ELECTRON BEAM FOCUS; GAUSSIAN DISTRIBUTION; FUSION ZONE GEOMETRY; FUSION ZONE GEOMETRY; SLIT FARADAY CUP; CHARACTERISTIC BEAM WIDTH; EB DISTRIBUTION MEASUREMENT AB Electron beam welding machine current distributions in the plane of the workpiece surface were measured by oscillating the beam across a narrow slit above a current collector. The beam focus location was varied from 2.54 cm (1 in.) above to 2.54 cm below the workpiece surface for beam currents of 4, 8 and 12 mA at 110 kV. Immediately following each beam current distribution measurement a bead-on-plate weld was made in 304L stainless steel. Welding results demonstrated quantitatively the strong effect of beam focus location on penetration, and that it is necessary to control beam focus coil current to within +/- 1% to achieve +/- 5% accuracy in joint penetration. A procedure for evaluating a characteristic beam width from the beam profile data was developed, and a correlation of the penetration data in terms of a beam width, which includes 95% of the current, is presented. RP HICKEN, GK (reprint author), SANDIA NATL LABS,DIV PROC DEV & FABRICAT,LIVERMORE,CA 94550, USA. NR 10 TC 12 Z9 12 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 MAR PY 1991 VL 70 IS 3 BP S69 EP S75 PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA EZ785 UT WOS:A1991EZ78500012 ER PT J AU FOWKES, FM KULP, MJ HOROTHAI, J EVEN, WR AF FOWKES, FM KULP, MJ HOROTHAI, J EVEN, WR TI ADSORPTION OF POLYSTYRENE ONTO NOBLE-METALS FROM THETA SOLVENTS SO COLLOIDS AND SURFACES LA English DT Article; Proceedings Paper CT SYMP AT THE 62ND SYMP OF THE AMERICAN CHEMICAL SOC ON COLLOIDS AND SURFACE SCIENCE : COLLOIDS IN ENVIRONMENTAL AND MATERIALS TECHNOLOGIES CY JUN 19-22, 1988 CL UNIVERSITY PARK, PA SP AMER CHEM SOC ID POLYMERS; STATES AB The adsorption of polystyrene onto noble metals from 3.3% solutions in five different theta solvents was measured on six noble metals at temperatures a few degrees above the theta temperatures. The amounts adsorbed (in mg m-2) on any given metal were of the same order of magnitude from all five of the theta solvents, but decreased two or three orders of magnitudes with a change of noble metals, in the following order: gold >> silver >> palladium, silver-palladium >> platinum >> iridium. The amounts adsorbed on gold from cyclohexane at 60-degrees-C decreased seven-fold with a forty-fold decrease of molecular weight, as predicted by Scheutjens and Fleer, but there was no molecular weight dependence to the weak adsorption observed on platinum and iridium. A direct method was used to determine the amount of polymer adsorbed on these metal powders. After the polymer solution and metal powder were equilibrate, the powder was washed free of excess polymer solution with fresh theta solvent and then the adsorbed polystyrene was removed from the metal by rinsing in chloroform, a very good solvent, in which the amount of polystyrene was determined by UV spectroscopy. With the high molecular weight polystyrene (1.8.10(6)) the differences in duplicate samples were about 2%, but with the lower molecular weight polystyrene (5.10(4)) they were about 25%. It is proposed that the high reproducibility of adsorption results observed with the high molecular weight polymer indicates negligible desorption during rinsing with the theta solvent, but that this rinsing step was less reproducible with the low molecular weight polymer. C1 SANDIA NATL LABS,LIVERMORE,CA 94550. RP FOWKES, FM (reprint author), LEHIGH UNIV,DEPT CHEM,BETHLEHEM,PA 18015, USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-6622 J9 COLLOID SURFACE PD FEB 28 PY 1991 VL 53 IS 3-4 BP 329 EP 337 DI 10.1016/0166-6622(91)80145-E PG 9 WC Chemistry, Physical SC Chemistry GA FB491 UT WOS:A1991FB49100010 ER PT J AU ELKOLALY, MT MAUSNER, LF SRIVASTAVA, SC AF ELKOLALY, MT MAUSNER, LF SRIVASTAVA, SC TI RADIOCHROMATOGRAPHY OF SOME MO-99(V) AND MO-99(VI) POLYAMINOCARBOXYLIC ACIDS SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-LETTERS LA English DT Article ID MONOCLONAL-ANTIBODY; QUALITY-CONTROL; TC-99M AB A simple, rapid and inexpensive ascending thin-layer and paper radiochromatographic procedure is described, which can be used in the separation and possible identification of some Mo-99 (V) and Mo-99 (VI) polyaminocarboxylic acid chelates. C1 BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP ELKOLALY, MT (reprint author), ATOM ENERGY AUTHOR,CTR NUCL RES,DEPT RADIOISOTOPE PROD & LABELLED CPDS,CAIRO,EGYPT. NR 20 TC 0 Z9 0 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 FEB 28 PY 1991 VL 153 IS 3 BP 171 EP 183 DI 10.1007/BF02176873 PG 13 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA FD579 UT WOS:A1991FD57900002 ER PT J AU FAIRLIE, DB ZACHOS, CK AF FAIRLIE, DB ZACHOS, CK TI MULTIPARAMETER ASSOCIATIVE GENERALIZATIONS OF CANONICAL COMMUTATION RELATIONS AND QUANTIZED PLANES SO PHYSICS LETTERS B LA English DT Article ID QUANTUM AB We explicitly deform classical oscillators to multiparameter quantum oscillators which do not commute with each other. These "anyonic" oscillators lead to the construction of a consistent quantum algebra GL(q)(N) with 1/2 (N - 1) (N - 2) dependent parameters, some of whose features and applications we discuss. C1 ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. RP FAIRLIE, DB (reprint author), UNIV DURHAM,DEPT MATH SCI,CTR PARTICLE THEORY,DURHAM DH1 3LE,ENGLAND. RI zachos, cosmas/C-4366-2014 OI zachos, cosmas/0000-0003-4379-3875 NR 26 TC 104 Z9 104 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 28 PY 1991 VL 256 IS 1 BP 43 EP 49 DI 10.1016/0370-2693(91)90216-D PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FB170 UT WOS:A1991FB17000010 ER PT J AU BULLOCK, RM RAPPOLI, BJ AF BULLOCK, RM RAPPOLI, BJ TI PREPARATION AND REACTIONS OF MN2(CO)9(ETA-1-ALDEHYDE) COMPLEXES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TRANSITION-METAL HYDRIDES; DIELS-ALDER REACTIONS; CARBON-MONOXIDE; LEWIS-ACIDS; REDUCTIVE ELIMINATION; HYDROFORMYLATION; CATALYSIS; ALDEHYDES; INSERTION; RHENIUM AB The reaction of HMn(CO)5 with RMn(CO)5 (R = CH3, p-CH3C6H4, or CH2CH2CH = C(Ph)CH3) gives Mn2-(CO)9(eta-1-RCHO) complexes. It is suggested that these Mn2(CO)9(eta-1-aldehyde) complexes may provide a model for a previously unobserved intermediate in the formation of aldehydes from the hydroformylation of olefins. The eta-1-aldehyde ligand is weakly bound to the manganese, as evidenced by its facile displacement by ligands such as CO, PPh3, and CH3CN. The kinetics of the reaction of HMn(CO)5 with (CO)5Mn(CH2CH2CH = C (Ph)CH3) were studied by H-1 NMR at 25-degrees-C in C6D6. The reaction is first-order in the manganese alkyl complex, and the rate of the reaction decreases slightly with increasing concentration of HMn(CO)5. A negligible isotope effect (k(H)/k(D) = 1.04 +/- 0.09) was found for the reaction of (CO)5Mn(CH2CH2CH = C(Ph)CH3) with DMn(CO)5. The reaction of Mn2(CO)9(eta-1-CH3CHO) with excess HMn(CO)5 takes several days at room temperature and produces ethanol and the manganese cluster complex Mn3(CO)9(mu-3-OEt)2(mu-2-OEt). RP BULLOCK, RM (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Bullock, R. Morris/L-6802-2016 OI Bullock, R. Morris/0000-0001-6306-4851 NR 62 TC 22 Z9 22 U1 1 U2 1 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 FEB 27 PY 1991 VL 113 IS 5 BP 1659 EP 1669 DI 10.1021/ja00005a033 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA EZ477 UT WOS:A1991EZ47700033 ER PT J AU OHLROGGE, JB BROWSE, J SOMERVILLE, CR AF OHLROGGE, JB BROWSE, J SOMERVILLE, CR TI THE GENETICS OF PLANT LIPIDS SO BIOCHIMICA ET BIOPHYSICA ACTA LA English DT Review DE LIPID COMPOSITION; PLANT LIPID; ACYL CARRIER PROTEIN; LIPID SYNTHESIS ID ACYL-CARRIER PROTEIN; FATTY-ACID COMPOSITION; PHOSPHOLIPID-TRANSFER PROTEIN; HIGH OLEIC-ACID; BODY MEMBRANE-PROTEIN; LOW LINOLENIC ACID; GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE ACTIVITY; DEVELOPING LINSEED COTYLEDONS; ENHANCED THERMAL TOLERANCE; INNER ENVELOPE MEMBRANE C1 MICHIGAN STATE UNIV,DOE PLANT RES LAB,E LANSING,MI 48824. WASHINGTON STATE UNIV,INST BIOL CHEM,PULLMAN,WA 99164. RP OHLROGGE, JB (reprint author), MICHIGAN STATE UNIV,DEPT BOT & PLANT PATHOL,E LANSING,MI 48824, USA. RI Somerville, Christopher/A-4048-2009; OI Somerville, Christopher/0000-0003-4647-0094; Browse, John/0000-0002-2554-2821 NR 191 TC 116 Z9 122 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-3002 J9 BIOCHIM BIOPHYS ACTA PD FEB 26 PY 1991 VL 1082 IS 1 BP 1 EP 26 DI 10.1016/0005-2760(91)90294-R PG 26 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA FC562 UT WOS:A1991FC56200001 PM 1901223 ER PT J AU BANCI, L BERTINI, I CABELLI, DE HALLEWELL, RA TUNG, JW VIEZZOLI, MS AF BANCI, L BERTINI, I CABELLI, DE HALLEWELL, RA TUNG, JW VIEZZOLI, MS TI A CHARACTERIZATION OF COPPER-ZINC SUPEROXIDE-DISMUTASE MUTANTS AT POSITION-124 - ZINC-DEFICIENT PROTEINS SO EUROPEAN JOURNAL OF BIOCHEMISTRY LA English DT Article ID SLOW ROTATING SYSTEMS; S = 1/2; SUBSTITUTED DERIVATIVES; ANION-BINDING; G-ANISOTROPY; MECHANISM; ENZYME; RECONSTITUTION; APOPROTEIN; RELAXATION AB Substitution of the completely conserved aspartic acid residue at position 124 of Cu,Zn superoxide dismutase with asparagine and glycine has been performed through site-directed mutagenesis on the human enzyme. Asp124 is H-bonded to the NH of two histidines, one of which is bound to copper and the other to zinc. The mutant proteins, as expressed in Escherichia coli, result in an essential zinc-free enzyme which is similar to that obtained from the wild-type derivative through chemical manipulation. Only by extensive dialysis against 0.5 M ZnCl2 or CoCl2 at pH 5.4 was it possible to reconstitute approximately 50% of the molecules in the Cu2Zn2 or Cu2Co2 form. The new derivatives have been characterized through EPR, CD and nuclear magnetic relaxation dispersion techniques. The Cu2Co(x) derivatives (x almost-equal-to 1) were used to monitor, through electronic and H-1-NMR spectroscopies, the metal sites which are found to be similar to those of the wild type. In addition, a double substitution with asparagine has been made, replacing the invariant aspartate at position 124 and the highly conserved aspartate at position 125. The behavior is similar to that of the other mutants in most respects. The Cu2E2 (E = empty) derivatives of the mutants are stable, even in the pH range 8-10, whereas in the case of the Cu2E2 derivative of the wild type, copper migration occurs at high pH, producing both Cu2Cu2 and apo derivatives. The activity measurements indicate that the various Cu2E2 derivatives have the same activity at low pH and similar to that of the holoenzyme. A full profile up to pH 10.5 was obtained for the mutants. C1 UNIV FLORENCE,DEPT CHEM,I-50121 FLORENCE,ITALY. BROOKHAVEN NATL LAB,DEPT CHEM,LONG ISL,NY. CHIRON CORP,EMERYVILLE,CA. NR 51 TC 47 Z9 47 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0014-2956 J9 EUR J BIOCHEM JI Eur. J. Biochem. PD FEB 26 PY 1991 VL 196 IS 1 BP 123 EP 128 DI 10.1111/j.1432-1033.1991.tb15794.x PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FB042 UT WOS:A1991FB04200017 PM 1848181 ER PT J AU SCHOENLEIN, RW BIGOT, JY PORTELLA, MT SHANK, CV AF SCHOENLEIN, RW BIGOT, JY PORTELLA, MT SHANK, CV TI GENERATION OF BLUE-GREEN 10 FS PULSES USING AN EXCIMER PUMPED DYE AMPLIFIER SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL PULSES; FEMTOSECONDS AB We report the generation of < 25 fs pulses in the blue-green spectral region at 450 and 500 nm, using a colliding-pulse-mode-locked laser combined with a two-stage excimer pumped dye amplifier and continuum generation. The blue-green pulses are compressed to 10 fs duration using an optical fiber with pairs of gratings and prisms for phase compensation. RP SCHOENLEIN, RW (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. RI Schoenlein, Robert/D-1301-2014 OI Schoenlein, Robert/0000-0002-6066-7566 NR 9 TC 43 Z9 44 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 25 PY 1991 VL 58 IS 8 BP 801 EP 803 DI 10.1063/1.104494 PG 3 WC Physics, Applied SC Physics GA EZ142 UT WOS:A1991EZ14200006 ER PT J AU CARIM, AH BASU, SN MUENCHAUSEN, RE AF CARIM, AH BASU, SN MUENCHAUSEN, RE TI DEPENDENCE OF CRYSTALLINE ORIENTATION ON FILM THICKNESS IN LASER-ABLATED YBA2CU3O7-DELTA ON LAALO3 SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; EPITAXIAL-GROWTH; SRTIO3; YBA2CU3O7-DELTA; SUBSTRATE AB The microstructure of YBa2Cu3O7-delta thin films deposited on (001)LaAlO3 substrates by a laser ablation process has been investigated by scanning electron microscopy, x-ray diffraction, and cross-sectional transmission electron microscopy. Adjacent to the substrate, the film is entirely oriented with the c-axis perpendicular to the surface. At a thickness of about 0.4-mu-m, the occurrence of 90-degrees boundaries brings about a transition to grains with their c-axes parallel to the surface (aligned along the [100] and [010] directions of the pseudocubic LaAlO3 substrate). This transition is discussed in terms of the crystal growth anisotropy and the retained strain that may precipitate the transition. C1 PENN STATE UNIV,CTR MICROENGINEERED CERAM,UNIVERSITY PK,PA 16802. PENN STATE UNIV,DEPT CHEM & NUCL ENGN,UNIVERSITY PK,PA 16802. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 22 TC 68 Z9 68 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 25 PY 1991 VL 58 IS 8 BP 871 EP 873 DI 10.1063/1.104491 PG 3 WC Physics, Applied SC Physics GA EZ142 UT WOS:A1991EZ14200030 ER PT J AU YANG, XZ BURGDORFER, J AF YANG, XZ BURGDORFER, J TI MOLECULAR-DYNAMICS APPROACH TO THE STATISTICAL PROPERTIES OF ENERGY-LEVELS SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM SPECTRA; PERIODIC-ORBITS; SYSTEMS; EIGENFUNCTIONS; DISTRIBUTIONS; TRAJECTORIES; TRANSITION; MOTION; CHAOS AB The deformation of the energy-level spectra of quantum systems as a function of a control parameter governing the strength of a nonintegrable perturbation can be determined by standard molecular-dynamics techniques. The integration of Newton's equations of motion provides detailed information on the spectral deformation when the classical system undergoes a transition from mostly regular to mostly chaotic motion. This method is used to study the changes in the energy-level statistics and allows the direct determination of the Brody parameter in the predominantly chaotic regime. C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RP UNIV TENNESSEE, DEPT PHYS, KNOXVILLE, TN 37996 USA. NR 26 TC 15 Z9 16 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 FEB 25 PY 1991 VL 66 IS 8 BP 982 EP 985 DI 10.1103/PhysRevLett.66.982 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400004 ER PT J AU FEINGOLD, M LEITNER, DM WILKINSON, M AF FEINGOLD, M LEITNER, DM WILKINSON, M TI SPECTRAL STATISTICS IN SEMICLASSICAL RANDOM-MATRIX ENSEMBLES SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHAOTIC SYSTEMS; ENERGY-LEVELS; LOCALIZATION; ELEMENTS; ORBITS AB A novel random-matrix ensemble is introduced which mimics the global structure inherent in the Hamiltonian matrices of autonomous, ergodic systems. Changes in its parameters induce a transition between a Poisson and a Wigner distribution for the level spacings, P(s). The intermediate distributions are uniquely determined by a single scaling variable. Semiclassical constraints force the ensemble to be in a regime with Wigner P(s) for systems with more than two freedoms. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV STRATHCLYDE,DEPT PHYS & APPL PHYS,GLASGOW G4 0NG,SCOTLAND. RI Feingold, Mario/F-1400-2012 OI Feingold, Mario/0000-0001-9316-5856 NR 21 TC 63 Z9 63 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 986 EP 989 DI 10.1103/PhysRevLett.66.986 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400005 ER PT J AU WARNOCK, RL RUTH, RD AF WARNOCK, RL RUTH, RD TI STABILITY OF NONLINEAR HAMILTONIAN MOTION FOR A FINITE BUT VERY LONG-TIME SO PHYSICAL REVIEW LETTERS LA English DT Article AB By constructing action variables that are very nearly invariant in a region-OMEGA of phase space, and by examining their residual variation, we set long-term bounds on any orbit starting in an open subregion of OMEGA. A new and generally applicable method for constructing the required high-precision invariants is applied. The technique is illustrated for transverse oscillations in a circular accelerator, a case with 2 1/2 degrees of freedom and strong nonlinearity. RP WARNOCK, RL (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 12 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 990 EP 993 DI 10.1103/PhysRevLett.66.990 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400006 ER PT J AU BHATTACHARYA, T GOCKSCH, A ALTES, CK PISARSKI, RD AF BHATTACHARYA, T GOCKSCH, A ALTES, CK PISARSKI, RD TI INTERFACE TENSION IN AN SU(N) GAUGE-THEORY AT HIGH-TEMPERATURE SO PHYSICAL REVIEW LETTERS LA English DT Article ID FINITE-TEMPERATURE; QUARK CONFINEMENT; TRANSITIONS; PHASE AB For an SU(N) gauge theory without dynamical fermions, at temperatures above the deconfining transition there are Z(N) degenerate vacua. The interface tension between distinct Z(N) vacua is computed in weak coupling by semiclassical techniques. C1 CNRS,CTR PHYS THEOR,SECT 2,I-13288 MARSEILLE,ITALY. RP BHATTACHARYA, T (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. RI Bhattacharya, Tanmoy/J-8956-2013 OI Bhattacharya, Tanmoy/0000-0002-1060-652X NR 26 TC 95 Z9 95 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 998 EP 1000 DI 10.1103/PhysRevLett.66.998 PG 3 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400008 ER PT J AU GOMEZCADENAS, JJ AF GOMEZCADENAS, JJ TI SEARCH FOR ELASTIC NONDIAGONAL LEPTON-PAIR PRODUCTION IN E+E- ANNIHILATION AT SQUARE-ROOT-S = 29 GEV SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLAVOR; DECAYS; MODEL; Z0; E6 AB We have searched for the annihilation of e+e- into the exclusive channels e +/- tau -/+ and mu +/- tau -/+ at square-root-s = 29 GeV, using 226 and 133 pb -1, respectively, of data taken with the Mark II detector at the SLAC storage ring PEP. The resulting candidate sample is compatible with the expected background from tau pair production. Our analysis yields 95%-C.L. cross-section limits of sigma-e-tau/sigma-mu-mu < 1.8 x 10(-3) and sigma-mu-tau/sigma-mu-mu < 6.1 x 10(-3), where sigma-mu-mu is the QED cross section for production of a lepton pair. This is the first high Q2 test of lepton-flavor conservation involving tau leptons. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. UNIV MICHIGAN,ANN ARBOR,MI 48109. UNIV COLORADO,BOULDER,CO 80309. CALTECH,PASADENA,CA 91125. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. INDIANA UNIV,BLOOMINGTON,IN 47405. UNIV HAWAII,HONOLULU,HI 96822. HARVARD UNIV,CAMBRIDGE,MA 02138. RP GOMEZCADENAS, JJ (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. RI Calvino, Francisco/K-5743-2014; Gomez Cadenas, Juan Jose/L-2003-2014 OI Calvino, Francisco/0000-0002-7198-4639; Gomez Cadenas, Juan Jose/0000-0002-8224-7714 NR 13 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1007 EP 1010 DI 10.1103/PhysRevLett.66.1007 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400011 ER PT J AU BAI, Z AF BAI, Z TI MEASUREMENT OF THE HADRONIC STRUCTURE OF SEMILEPTONIC D(0) AND D(+) DECAYS SO PHYSICAL REVIEW LETTERS LA English DT Article ID D-MESONS AB Absolute branching fractions for the D(l)3 and D(l)4 decays D+ --> KBAR0e + v(e), D+ --> KBAR0-mu + v-mu, D+ --> KBAR*0e + v(e), and D0 --> K*-e + v(e) are determined using completely reconstructed DDBAR events at the psi(3770). Reconstructed D0 --> K-e+v(e) decays are used to determine the pole mass of the f + (q2) form factor. Resonant K* production dominates the process D --> K-pi-ev; the K* polarization is measured. Limits on several Cabibbo-suppressed channels are evaluated. A global fit imposing isospin symmetry is performed to the measured exclusive and inclusive semileptonic D0 and D+ branching fractions to obtain an improved set of branching fractions. C1 UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. UNIV ILLINOIS,URBANA,IL 61801. UNIV WASHINGTON,SEATTLE,WA 98195. UNIV IOWA,IOWA CITY,IA 52241. STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP BAI, Z (reprint author), CALTECH,PASADENA,CA 91125, USA. OI Burchell, Mark/0000-0002-2680-8943 NR 15 TC 59 Z9 61 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1011 EP 1014 DI 10.1103/PhysRevLett.66.1011 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400012 ER PT J AU SCHMIEDMAYER, J RIEHS, P HARVEY, JA HILL, NW AF SCHMIEDMAYER, J RIEHS, P HARVEY, JA HILL, NW TI MEASUREMENT OF THE ELECTRIC POLARIZABILITY OF THE NEUTRON SO PHYSICAL REVIEW LETTERS LA English DT Article ID MIT BAG MODEL; ELECTROMAGNETIC POLARIZABILITY; QUARK MODELS; SCATTERING; NUCLEON AB The electric polarizability of the neutron was determined to be alpha-n = (1.20 +/- 0.15 +/- 0.20) x 10(-3) fm3 from its characteristic influence on the energy dependence of the neutron-Pb-208 scattering cross section, as measured in a neutron time-of-flight transmission experiment at the Oak Ridge Electron Linear Accelerator pulsed neutron source. C1 VIENNA TECH UNIV,INST KERNPHYS,A-1040 VIENNA,AUSTRIA. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RI Schmiedmayer, Jorg/B-4717-2008 OI Schmiedmayer, Jorg/0000-0001-7799-5614 NR 37 TC 140 Z9 140 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1015 EP 1018 DI 10.1103/PhysRevLett.66.1015 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400013 ER PT J AU KNUDSON, JN BOWMAN, JD PENTTILA, SI COMFORT, JR RITCHIE, BG GOERGEN, J MATHIS, D TINSLEY, J HANNA, SS KING, B POCANIC, D LOVEMAN, RA FRITZ, LS DIXON, NS AF KNUDSON, JN BOWMAN, JD PENTTILA, SI COMFORT, JR RITCHIE, BG GOERGEN, J MATHIS, D TINSLEY, J HANNA, SS KING, B POCANIC, D LOVEMAN, RA FRITZ, LS DIXON, NS TI NEUTRON DEFORMATION IN HO-165 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-CHARGE-EXCHANGE; INELASTIC-SCATTERING; DEFORMED-NUCLEI AB Measurements are reported of orientation asymmetries in the forward-angle differential cross sections for pion single-charge-exchange scattering of aligned and unaligned Ho-165 nuclei. The extrapolated 0-degrees asymmetry of -0.022 +/- 0.024 indicates a quadrupole deformation ratio beta-2-n/beta-2-c = 0.84 +/- 0.08. This result conflicts with the predictions of the best available Hartree-Fock models. C1 ARIZONA STATE UNIV,DEPT PHYS,TEMPE,AZ 85287. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. FRANKLIN & MARSHALL COLL,DEPT PHYS,LANCASTER,PA 17604. RP KNUDSON, JN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 24 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1026 EP 1029 DI 10.1103/PhysRevLett.66.1026 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400016 ER PT J AU AZAIEZ, F KELLY, WH KORTEN, W STEPHENS, FS DELEPLANQUE, MA DIAMOND, RM MACCHIAVELLI, AO DRAPER, JE RUBEL, EC BEAUSANG, CW BURDE, J BECKER, JA HENRY, EA YATES, SW BRINKMAN, MJ KUHNERT, A WANG, TF AF AZAIEZ, F KELLY, WH KORTEN, W STEPHENS, FS DELEPLANQUE, MA DIAMOND, RM MACCHIAVELLI, AO DRAPER, JE RUBEL, EC BEAUSANG, CW BURDE, J BECKER, JA HENRY, EA YATES, SW BRINKMAN, MJ KUHNERT, A WANG, TF TI 6 IDENTICAL SUPERDEFORMED BANDS IN TL-194 SO PHYSICAL REVIEW LETTERS LA English DT Article AB Four new superdeformed bands have been observed in 194Tl, in addition to the two already reported. These six bands consist of three signature-partner pairs, whose energies and spacings resemble closely those in the two superdeformed bands recently reported in 193Tl. The transition-energy similarities and angular momentum alignments of these bands are discussed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CEN BORDEAUX GRADIGNAN,F-33170 GRADIGNAN,FRANCE. IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV LIVERPOOL,LIVERPOOL L69 3BX,ENGLAND. HEBREW UNIV JERUSALEM,RACAH INST PHYS,JERUSALEM,ISRAEL. UNIV KENTUCKY,LEXINGTON,KY 40506. RUTGERS STATE UNIV,NEW BRUNSWICK,NJ 08090. RP AZAIEZ, F (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. RI KORTEN, Wolfram/H-3043-2013; OI KORTEN, Wolfram/0000-0002-3940-0816 NR 14 TC 51 Z9 51 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1030 EP 1033 DI 10.1103/PhysRevLett.66.1030 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400017 ER PT J AU MCCORMACK, EF EYLER, EE AF MCCORMACK, EF EYLER, EE TI PERTURBED STRUCTURE OF MOLECULAR-HYDROGEN NEAR THE 2ND DISSOCIATION LIMIT SO PHYSICAL REVIEW LETTERS LA English DT Article ID HOMONUCLEAR DIATOMIC-MOLECULES; QUANTUM DEFECT ANALYSIS; U-G PERTURBATIONS; HYPERFINE INTERACTIONS; ABINITIO CALCULATION; ABSORPTION-SPECTRUM; SYMMETRY-BREAKING; STATES; PHOTODISSOCIATION; ENERGY AB The region of the second dissociation limit of H2 converging to H(1s) + H(2s, 2p) has been investigated using high-resolution double-resonance spectroscopy through the E, F1-SIGMA-g+ state. Transitions to the very high vibrational levels of the B1-SIGMA-u+, B'1-SIGMA-u+, and C1-PI-u states have been measured with 0.02-cm-1 accuracy. Numerous perturbations and unexpected transitions are observed as far as 10 cm-1 below the dissociation limit. This complex structure, still not fully understood, arises from a combination of electronic, fine-structure, and hyperfine interactions. C1 UNIV DELAWARE,DEPT PHYS & ASTRON,NEWARK,DE 19716. RP MCCORMACK, EF (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 37 TC 30 Z9 30 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1042 EP 1045 DI 10.1103/PhysRevLett.66.1042 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400020 ER PT J AU SUPERFINE, R HUANG, JY SHEN, YR AF SUPERFINE, R HUANG, JY SHEN, YR TI NONLINEAR OPTICAL STUDIES OF THE PURE LIQUID VAPOR INTERFACE - VIBRATIONAL-SPECTRA AND POLAR ORDERING SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUM-FREQUENCY GENERATION; 2ND HARMONIC-GENERATION; 2ND-HARMONIC GENERATION; SURFACE; SPECTROSCOPY; ORIENTATION; AUGER; PHASE; WATER AB Using infrared-visible sum-frequency generation we have obtained the vibrational spectra of CH stretches of methanol molecules at the interface between methanol vapor and liquid. This is the first vibrational spectrum ever observed from a neat liquid surface. The measured polarization dependence and phase of the nonlinear susceptibility allow us to conclude that the surface methanol molecules are polar oriented with the CH3 group pointing away from the liquid with a very broad orientational distribution. RP SUPERFINE, R (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT PHYS,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. RI Superfine, Richard/A-1968-2012 NR 28 TC 158 Z9 159 U1 3 U2 36 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 25 PY 1991 VL 66 IS 8 BP 1066 EP 1069 DI 10.1103/PhysRevLett.66.1066 PG 4 WC Physics, Multidisciplinary SC Physics GA EZ134 UT WOS:A1991EZ13400026 ER PT J AU ERCK, R AF ERCK, R TI STAR TREK-17 SO NEW SCIENTIST LA English DT Letter RP ERCK, R (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 1 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 FEB 23 PY 1991 VL 129 IS 1757 BP 3 EP 3 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EY918 UT WOS:A1991EY91800012 ER PT J AU KRAUSS, RM AF KRAUSS, RM TI THE TANGLED WEB OF CORONARY RISK-FACTORS SO AMERICAN JOURNAL OF MEDICINE LA English DT Article ID LIPOPROTEIN SUBCLASS PATTERNS; ARTERY DISEASE; DENSITY LIPOPROTEINS; INTERMEDIATE AB Although epidemiologic, genetic, and pathophysiologic studies have shown that low-density lipoproteins (LDLs) are involved in the development of coronary artery disease, the standard measurement of LDL cholesterol comprises a number of separate components that may contribute in different ways to the disease process. Some of these components appear to be of particular pathologic importance. Intermediate-density lipoproteins (IDLs) and lipoprotein (a) are highly atherogenic species that each normally account for up to 10% to 15% total LDL cholesterol but may be disproportionately elevated in pathologic states and may therefore contribute disproportionately to coronary disease risk in certain patients. Recently, another subclass of LDL, characterized by relatively small particle size and increased density, also has been found to be associated with relatively increased risk of coronary disease. Furthermore, levels of this subclass, designated LDL-III, are linked to a number of interrelated hormonal and metabolic factors, each of which have also been associated with risk of coronary artery disease. These include male gender, post-menopause, abdominal adiposity, elevated triglyceride levels, increased levels of apolipoprotein B, and reductions in high-density lipoproteins (HDLs), particularly in the HDL2 subclass. Other studies have demonstrated that many of these factors are also commonly associated with relative insulin resistance and hyperinsulinemia. Thus, a lipoprotein profile characterized by a relative increase in LDL-III and a reduction in HDL2 is indicative of a constellation of metabolic features that defines a high-risk state and that makes it extremely difficult to single out one or more factors that are most directly involved in the disease process. Combinations of genetic and environmental factors acting on this "tangled web" of risk factors may account for much of the variation in coronary disease susceptibility found in the general population. C1 UNIV CALIF BERKELEY,DONNER LAB,DIV RES MED & RADIAT BIOPHYS,MOLEC MED RES PROGRAM,BERKELEY,CA 94720. RP KRAUSS, RM (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV RADIAT BIOPHYS,MS DONNER 465,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL 18574] NR 18 TC 32 Z9 33 U1 0 U2 0 PU EXCERPTA MEDICA INC PI NEW YORK PA 245 WEST 17TH STREET, NEW YORK, NY 10011 SN 0002-9343 J9 AM J MED JI Am. J. Med. PD FEB 21 PY 1991 VL 90 SU 2A BP S36 EP S41 DI 10.1016/0002-9343(91)90035-V PG 6 WC Medicine, General & Internal SC General & Internal Medicine GA EZ476 UT WOS:A1991EZ47600010 PM 1994714 ER PT J AU YEH, E DRISCOLL, R COLTRERA, M OLINS, A BLOOM, K AF YEH, E DRISCOLL, R COLTRERA, M OLINS, A BLOOM, K TI A DYNAMIN-LIKE PROTEIN ENCODED BY THE YEAST SPORULATION GENE SPO15 SO NATURE LA English DT Article ID SACCHAROMYCES-CEREVISIAE; CELL-CYCLE; MICROTUBULES AB THE tightly centromere-linked gene SPO15 is essential for meiotic cell division in the yeast Saccharomyces cerevisiae. Diploid cells without the intact SPO15 gene product are able to complete premeiotic DNA synthesis and genetic recombination, but are unable to traverse the division cycles. Electron microscopy of blocked cells reveals a duplicated but unseparated spindle-pole body. Thus cells are unable to form a bipolar spindle. Sequence analysis of SPO15 DNA reveals an open reading frame that predicts a protein of 704 amino acids. This protein is identical to VPS1, a gene involved in vacuolar protein sorting in yeast which has significant sequence homology (45% overall, 66% over 300 amino acids) to the microtubule bundling-protein, dynamin. The SPO15 gene product expressed in Escherichia coli can be affinity-purified with microtubules. SPO15 encodes a protein that is likely to be involved in a microtubule-dependent process required for the timely separation of spindle-pole bodies in meiosis C1 UNIV WASHINGTON,DEPT OTOLARYNGOL,SEATTLE,WA 98195. UNIV TENNESSEE,GRAD SCH BIOMED SCI,DIV BIOL,OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP YEH, E (reprint author), UNIV N CAROLINA,DEPT BIOL,CHAPEL HILL,NC 27599, USA. NR 11 TC 76 Z9 77 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 21 PY 1991 VL 349 IS 6311 BP 713 EP 715 DI 10.1038/349713a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EY627 UT WOS:A1991EY62700053 PM 1825352 ER PT J AU CHOU, WT ZHANG, JY CASTEN, RF BRENNER, DS AF CHOU, WT ZHANG, JY CASTEN, RF BRENNER, DS TI SHELL STRUCTURE IN EMPIRICAL P-N INTERACTIONS - COMPARISON WITH NILSSON AND SHELL-MODEL CALCULATIONS SO PHYSICS LETTERS B LA English DT Article ID ZR-91; D,P AB Calculations of the variations of residual proton-neutron (p-n) interaction matrix elements for three different mass regions are presented within the frameworks of two approaches, the Nilsson and shell models, which differ substantially in the basis states and interactions used. The excellent agreement obtained with experiment in both approaches points to the simplicity of the underlying physics in terms of orbital overlap arguments. C1 INST MODERN PHYS,LANZHOU,PEOPLES R CHINA. JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. CLARK UNIV,WORCESTER,MA 01610. CHINESE CTR ADV SCI & TECHNOL,WORLD LAB,CTR THEORET PHYS,BEIJING,PEOPLES R CHINA. RP CHOU, WT (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 11 TC 11 Z9 11 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 FEB 21 PY 1991 VL 255 IS 4 BP 487 EP 492 DI 10.1016/0370-2693(91)90254-N PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ875 UT WOS:A1991EZ87500003 ER PT J AU DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MATO, P MIQUEL, R MIR, LM ORTEU, S PACHECO, A PERLAS, JA TUBAU, E CATANESI, MG CREANZA, D DE PALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ALBRECHT, H ATWOOD, WB BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BROWN, D BURNETT, TH DREVERMANN, H DYDAK, F FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S JOST, B KASEMANN, M KELLNER, G KNOBLOCH, J LACOURT, A LEHRAUS, I LOHSE, T LUKE, D MARCHIORO, A MARTINEZ, M MAY, J MENARY, S MINTEN, A MIOTTO, A NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROTH, A ROTHBERG, J ROTSCHEIDT, H VON RUDEN, W ST DENIS, R SCHLATTER, D TAKASHIMA, M TALBY, M TEJESSY, W WACHMUTH, H WASSERBAECH, S WHEELER, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BARDADIN-OTWINOWSKA, M FALVARD, A EL FELLOUS, R GAY, P HARVEY, J HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NIELSEN, ER NILSSON, BS PETERSEN, G EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BOUROTTE, J BRAEMS, F BRIENT, JC FOUQUE, G GAMESS, A GUIRLET, R ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CHIARELLA, V D'ETTORRE-PIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MASSIMO-BRANCACCIO, F MURTAS, F MURTAS, GP NICOLETTI, G PASSALACQUA, L PEPE-ALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O HALLEY, AW TEN HAVE, I HEARNS, JL LYNCH, JG MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF PATTON, SJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G KEEMER, NR NUTTALL, M ROWLINGSON, BS SLOAN, T SNOW, SW BARCZEWSKI, T BAUERDICK, LAT KLEINKNECHT, K RENK, B ROEHN, S SANDER, HG SCHMELLING, M SCHMIDT, H STEEG, F ALBANESE, JP AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A COURVOISIER, D ETIENNE, F PAPALEXIOU, S PAYRE, P PIETRZYK, B QIAN, Z BLUM, W CATTANEO, P COWAN, G DEHNING, B DIETL, H FERNANDEZ-BOSMAN, M HANSL-KOZANECKA, T HAUSER, G JAHN, A KOZANECKI, W LANGE, E LUTJENS, G LUTZ, G MANNER, W MOSER, HG PAN, Y RICHTER, R SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U THOMAS, J WOLF, G BERTIN, V DE BOUARD, G BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GANIS, G GRIVAZ, JF HEUSSE, P JANOT, P JOURNE, V KIM, DW LEFRANCOIS, J LUTZ, AM VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F AMENDOLIAA, SR BAGLIESIA, G BATIGNANIA, G BOSISIOA, L BOTTIGLIA, U BRADASHIAA, C CIOCCIA, MA FERRANTE, I FIDECAROA, F FOAA, L FOCARDIA, E FORTIA, F GIASSIA, A GIORGIA, MA LIGABUEA, F LUSIANIA, A MANNELLIA, EB MARROCCHESIA, PS MESSINEOA, A MONETAA, L PALLAA, F SANGUINETTIA, G STEINBERGERA, J TENCHINIA, R TONELLIA, G TRIGGIANIA, G VENTURIA, A WALSHA, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T SAICH, MR STRONG, JA THOMAS, RM WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCH-DEVAUX, B COLAS, P KLOPFENSTEIN, C LANCON, E LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, R CARTWRIGHT, S COMBLEY, F DINSDALE, M DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BRANDT, S BURKHARDT, H GRUPEN, C MEINHARD, H MIRABITO, L NEUGEBAUER, E SCHAFER, U SEYWERD, H APOLLINARIA, G GIANNINIA, G GOBBOA, B LIELLOA, F ROLANDIA, L STIEGLERA, U BELLANTONI, L BOUDREAU, JF CINABRO, D CONWAY, JS COWEN, DF DEWEERD, AJ FENG, Z FERGUSON, DPS GAO, YS HARTON, JL HILGART, J JACOBSEN, JE JARED, RC JOHNSON, RP LECLAIRE, BW PAN, YB PARKER, T PATER, JR SAADI, Y SHARMA, V WEAR, JA WEBER, FV WU, SL ZOBERNIG, G AF DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MATO, P MIQUEL, R MIR, LM ORTEU, S PACHECO, A PERLAS, JA TUBAU, E CATANESI, MG CREANZA, D DE PALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ALBRECHT, H ATWOOD, WB BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BROWN, D BURNETT, TH DREVERMANN, H DYDAK, F FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S JOST, B KASEMANN, M KELLNER, G KNOBLOCH, J LACOURT, A LEHRAUS, I LOHSE, T LUKE, D MARCHIORO, A MARTINEZ, M MAY, J MENARY, S MINTEN, A MIOTTO, A NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROTH, A ROTHBERG, J ROTSCHEIDT, H VON RUDEN, W ST DENIS, R SCHLATTER, D TAKASHIMA, M TALBY, M TEJESSY, W WACHMUTH, H WASSERBAECH, S WHEELER, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BARDADIN-OTWINOWSKA, M FALVARD, A EL FELLOUS, R GAY, P HARVEY, J HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NIELSEN, ER NILSSON, BS PETERSEN, G EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BOUROTTE, J BRAEMS, F BRIENT, JC FOUQUE, G GAMESS, A GUIRLET, R ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CHIARELLA, V D'ETTORRE-PIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MASSIMO-BRANCACCIO, F MURTAS, F MURTAS, GP NICOLETTI, G PASSALACQUA, L PEPE-ALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O HALLEY, AW TEN HAVE, I HEARNS, JL LYNCH, JG MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF PATTON, SJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D RUDOLPH, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G KEEMER, NR NUTTALL, M ROWLINGSON, BS SLOAN, T SNOW, SW BARCZEWSKI, T BAUERDICK, LAT KLEINKNECHT, K RENK, B ROEHN, S SANDER, HG SCHMELLING, M SCHMIDT, H STEEG, F ALBANESE, JP AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A COURVOISIER, D ETIENNE, F PAPALEXIOU, S PAYRE, P PIETRZYK, B QIAN, Z BLUM, W CATTANEO, P COWAN, G DEHNING, B DIETL, H FERNANDEZ-BOSMAN, M HANSL-KOZANECKA, T HAUSER, G JAHN, A KOZANECKI, W LANGE, E LUTJENS, G LUTZ, G MANNER, W MOSER, HG PAN, Y RICHTER, R SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U THOMAS, J WOLF, G BERTIN, V DE BOUARD, G BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GANIS, G GRIVAZ, JF HEUSSE, P JANOT, P JOURNE, V KIM, DW LEFRANCOIS, J LUTZ, AM VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F AMENDOLIAA, SR BAGLIESIA, G BATIGNANIA, G BOSISIOA, L BOTTIGLIA, U BRADASHIAA, C CIOCCIA, MA FERRANTE, I FIDECAROA, F FOAA, L FOCARDIA, E FORTIA, F GIASSIA, A GIORGIA, MA LIGABUEA, F LUSIANIA, A MANNELLIA, EB MARROCCHESIA, PS MESSINEOA, A MONETAA, L PALLAA, F SANGUINETTIA, G STEINBERGERA, J TENCHINIA, R TONELLIA, G TRIGGIANIA, G VENTURIA, A WALSHA, J CARTER, JM GREEN, MG MARCH, PV MEDCALF, T SAICH, MR STRONG, JA THOMAS, RM WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCH-DEVAUX, B COLAS, P KLOPFENSTEIN, C LANCON, E LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, R CARTWRIGHT, S COMBLEY, F DINSDALE, M DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BRANDT, S BURKHARDT, H GRUPEN, C MEINHARD, H MIRABITO, L NEUGEBAUER, E SCHAFER, U SEYWERD, H APOLLINARIA, G GIANNINIA, G GOBBOA, B LIELLOA, F ROLANDIA, L STIEGLERA, U BELLANTONI, L BOUDREAU, JF CINABRO, D CONWAY, JS COWEN, DF DEWEERD, AJ FENG, Z FERGUSON, DPS GAO, YS HARTON, JL HILGART, J JACOBSEN, JE JARED, RC JOHNSON, RP LECLAIRE, BW PAN, YB PARKER, T PATER, JR SAADI, Y SHARMA, V WEAR, JA WEBER, FV WU, SL ZOBERNIG, G TI MEASUREMENT OF THE STRONG COUPLING-CONSTANT ALPHA-S FROM GLOBAL EVENT-SHAPE VARIABLES OF HADRONIC Z-DECAYS SO PHYSICS LETTERS B LA English DT Article ID E+E-ANNIHILATION; PERTURBATIVE QCD; MONTE-CARLO AB An analysis of global event-shape variables has been carried out for the reaction e+e- --> Z0 --> hadrons to measure the strong coupling constant alpha-s. This study is based on 52 720 hadronic events obtained in 1989/90 with the ALEPH detector at the LEP collider at energies near the peak of the Z-resonance. In order to determine alpha-s, second order QCD predictions modified by effects of perturbative higher orders and hadronization were fitted to the experimental distributions of event-shape variables. From a detailed analysis of the theoretical uncertainties we find that this approach is best justified for the differential two-jet rate, from which we obtain alpha-s(M(z2) = 0.121 +/- 0.002(stat.) +/- 0.003(sys.) +/- 0.007(theor.) using a renormalization scale mu = 1/2M(z). The dependence of alpha-s(M(z2) on mu is parameterized. For scales m(b) < mu < M(z) the result varies by -0.012-+0.007. C1 CNRS, IN2P3, LAB PHYS PARTICULES LAPP, F-74119 ANNECY LE VIEUX, FRANCE. UNIV AUTONOMA BARCELONA, LAB FIS ALTAS ENERGIAS, E-08193 BARCELONA, SPAIN. UNIV BARI, DIPARTIMENTO FIS, I-70126 BARI, ITALY. IST NAZL FIS NUCL, SEZ BARI, I-70126 BARI, ITALY. ACAD SINICA, INST HIGH ENERGY PHYS, BEIJING, PEOPLES R CHINA. CERN, EUROPEAN LAB PARTICLE PHYS, CH-1211 GENEVA 23, SWITZERLAND. UNIV BLAISE PASCAL, CNRS, IN2P3, LAB PHYS CORPUSCULAIRE, F-63177 AUBIERE, FRANCE. NIELS BOHR INST, DK-2100 COPENHAGEN, DENMARK. NUC RES CTR DEMOKRITOS, ATHENS, GREECE. ECOLE POLYTECH, CNRS, IN2P3, LAB PHYS NUCL & HAUTES ENERGIES, F-91128 PALAISEAU, FRANCE. UNIV EDINBURGH, DEPT PHYS, EDINBURGH EH9 3JZ, MIDLOTHIAN, SCOTLAND. UNIV FIRENZE, DIPARTIMENTO FIS, I-50125 FLORENCE, ITALY. IST NAZL FIS NUCL, SEZ FIRENZE, I-50125 FLORENCE, ITALY. FLORIDA STATE UNIV, DEPT PHYS, TALLAHASSEE, FL 32306 USA. FLORIDA STATE UNIV, SUPERCOMP COMPUTAT RES INST, TALLAHASSEE, FL 32306 USA. IST NAZL FIS NUCL, LNF, I-00044 FRASCATI, ITALY. UNIV GLASGOW, DEPT PHYS & ASTRON, GLASGOW G12 8QQ, LANARK, SCOTLAND. UNIV HEIDELBERG, INST HOCHENERGIEPHYS, W-6900 HEIDELBERG, GERMANY. IMPERIAL COLL, DEPT PHYS, LONDON SW7 2BZ, ENGLAND. UNIV INSSBRUCK, INST EXPT PHYS, A-6020 INNSBRUCK, AUSTRIA. UNIV LANCESTER, DEPT PHYS, LANCESTER LA1 4YB, ENGLAND. UNIV MAINZ, INST PHYS, W-6500 MAINZ, GERMANY. FAC SCI LUMINY, CNRS, IN2P3, CTR PHYS PARTICULES, F-13288 MARSEILLE, FRANCE. WERNER HEISENBERG INST PHYS, MAX PLANCK INST PHYS & ASTROPHYS, W-8000 MUNICH, GERMANY. UNIV PARIS SUD, CNRS, IN2P3, LAB ACCELERATEUR LINEAIRE, F-91405 ORSAY, FRANCE. SCUOLA NORMALE SUPER, I-56010 PISA, ITALY. UNIV PISA, DIPARTIMENTO FIS, INFN, SEZ PISA, I-56010 PISA, ITALY. UNIV LONDON, ROYAL HOLLOWAY & BEDFORD NEW COLL, DEPT PHYS, SURREY TW20 0EX, ENGLAND. RUTHERFORD APPLETON LAB, PARTICLE PHYS DEPT, DIDCOT OX11 0QX, OXON, ENGLAND. CEN SACLAY, DEPT PHYS PARTICLES ELEMENTAIRES, F-91191 GIF SUR YVETTE, FRANCE. UNIV SHEFFIELD, DEPT PHYS, SHEFFIELD S3 7RH, ENGLAND. UNIV SIEGEN, FACHBEREICH PHYS, W-5900 SIEGEN, GERMANY. IST NAZL FIS NUCL, SEZ TRIESTE, I-34127 TRIESTE, ITALY. UNIV TRIESTE, DIPARTIMENTO FIS, I-34127 TRIESTE, ITALY. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. DESY, W-2000 HAMBURG, GERMANY. FAC SCI, CTR PHYS PARTICULES, F-13288 MARSEILLE 9, FRANCE. UNIV TORINO, IST FIS GEN, TURIN, ITALY. CNR, IST COSMO GEOFIS, I-10133 TURIN, ITALY. LBL, BERKELEY, CA 94720 USA. RP DECAMP, D (reprint author), CNRS, IN2P3, LAB PHYS PARTICULES LAPP, F-74119 ANNECY LE VIEUX, FRANCE. RI Rolandi, Luigi (Gigi)/E-8563-2013; Ligabue, Franco/F-3432-2014; Venturi, Andrea/J-1877-2012; Colas, Paul/F-2876-2013; Bosman, Martine/J-9917-2014; Fernandez, Enrique/L-5387-2014; Mir, Lluisa-Maria/G-7212-2015; Murtas, Fabrizio/B-5729-2012; Booth, Christopher/B-5263-2016; Delfino, Manuel/A-1545-2012; Pacheco Pages, Andres/C-5353-2011; Ferrante, Isidoro/F-1017-2012; OI Bottigli, Ubaldo/0000-0002-0666-3433; Rolandi, Luigi (Gigi)/0000-0002-0635-274X; Ligabue, Franco/0000-0002-1549-7107; Bloch-Devaux, Brigitte/0000-0002-2463-1232; Bosman, Martine/0000-0002-7290-643X; Fernandez, Enrique/0000-0002-6405-9488; Mir, Lluisa-Maria/0000-0002-4276-715X; Booth, Christopher/0000-0002-6051-2847; Delfino, Manuel/0000-0002-9468-4751; Pacheco Pages, Andres/0000-0001-8210-1734; Ferrante, Isidoro/0000-0002-0083-7228; Palazzi, Paolo/0000-0002-4861-391X; RASO, Giuseppe/0000-0002-5660-3711 NR 28 TC 50 Z9 50 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 21 PY 1991 VL 255 IS 4 BP 623 EP 633 DI 10.1016/0370-2693(91)90278-X PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ875 UT WOS:A1991EZ87500027 ER PT J AU MONTGOMERY, D LEE, YC AF MONTGOMERY, D LEE, YC TI STATISTICAL-MECHANICAL SELECTION OF THE SHAPES OF DISK GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, GENERAL; GALAXIES, STRUCTURE ID NEGATIVE TEMPERATURE STATES; SINH-POISSON EQUATION; GUIDING-CENTER PLASMA; VORTICES; MODELS AB A new method is proposed for selecting steady state shapes of disk galaxies as "most probable states" of a large number of stars, given only the total energy and total angular momentum. A partial differential equation is derived for the mean gravitational potential; it is closely related to the "sinh-Poisson" equation for the mean-field description of a line vortex system or electrostatic guiding-center plasma. A "water bag" approximation to the distribution function for bound stars renders the equation analytically tractable, but accurate solution of it may require numerical integration, in view of its general nonlinearity. C1 UNIV CALIF LOS ALAMOS SCI LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. RP MONTGOMERY, D (reprint author), DARTMOUTH COLL, DEPT PHYS & ASTRON, HANOVER, NH 03755 USA. NR 20 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1991 VL 368 IS 2 BP 380 EP 382 DI 10.1086/169702 PN 1 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX185 UT WOS:A1991EX18500007 ER PT J AU RYU, D VISHNIAC, ET AF RYU, D VISHNIAC, ET TI THE DYNAMIC INSTABILITY OF ADIABATIC BLAST WAVES SO ASTROPHYSICAL JOURNAL LA English DT Article DE HYDRODYNAMICS; INSTABILITIES; INTERSTELLAR, MATTER; NEBULAE, PLANETARY; SHOCK WAVES; STARS, SUPERNOVAE ID RAYLEIGH-TAYLOR INSTABILITY; SELF-SIMILAR FLOW; SUPERNOVA 1987A; SHOCK-WAVES; SN 1987A; STABILITY; FRAGMENTATION; EXPANSION; SN-1987A; SN1987A AB Adiabatic blast waves, which have a total energy injected from the center, E proportional-to t(q), and propagate through a preshock medium with a density P(E) proportional-to tau-omega, are described by a family to similarity solutions. Previous work has shown that adiabatic blast waves with increasing or constant postshock entropy behind the shock front are susceptible to an oscillatory instability, caused by the difference between the nature of the forces on the two sides of the dense shell behind the shock front. This instability sets in if the dense postshock layer is sufficiently thin. In this paper we consider the stability of adiabatic blast waves with a decreasing postshock entropy. Such blast waves, if they are decelerating, always have a region behind the shock front which is subject to convection. Some accelerating blast waves also have such a region, depending on the values of q, omega, and gamma, where gamma is the adiabatic index. However, since the shock interface stabilizes dynamically induced perturbations, blast waves become convectively unstable only if the convective zone is localized around the origin or a contact discontinuity far from the shock front. On the other hand, the contact discontinuity of accelerating blast waves is subject to a strong Rayleigh-Taylor instability. The frequency spectra of the nonradial, normal modes of adiabatic blast waves have been calculated. We discuss the implications of this work for two astrophysical interests, the instability of shocks propagating through supernova envelopes and the evolution of planetary nebulae. C1 UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. RP RYU, D (reprint author), FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,MS 209,POB 500,BATAVIA,IL 60510, USA. RI Ryu, Dongsu/C-2270-2016 OI Ryu, Dongsu/0000-0002-5455-2957 NR 37 TC 39 Z9 39 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1991 VL 368 IS 2 BP 411 EP 425 DI 10.1086/169706 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX185 UT WOS:A1991EX18500011 ER PT J AU CHANMUGAM, G LANGER, SH AF CHANMUGAM, G LANGER, SH TI FORMULAS FOR THE CYCLOTRON LUMINOSITY OF MAGNETIZED PLASMA SLABS SO ASTROPHYSICAL JOURNAL LA English DT Article DE MAGNETIC FIELDS; PLASMAS; RADIATION MECHANISMS; STARS, NEUTRON; STARS, WHITE DWARFS ID ACCRETION COLUMNS; AM HERCULIS; X-RAY; ABSORPTION; EMISSION; RADIATION; STARS AB Cyclotron emission from a uniform plasma slab can be approximated by a Rayleigh-Jeans spectrum that cuts off sharply at an effective frequency m*omega-c, where omega-c is the cyclotron frequency. We use accurate opacities to present significantly improved, numerically derived, formulae for m* as a function of plasma temperatures in the range 5 less-than-or-similar-to kT less-than-or-similar-to 50 keV and the dimensionless plasma parameter LAMBDA in the range 10(4)-10(8). Unlike many previous estimates, our formulae take account of the angular dependence of the cyclotron opacity and the high-frequency optically thin emission. In addition to being applicable to fusion plasmas, our formulae are also valid for the much higher values of LAMBDA-characteristic of many astrophysical plasmas. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP CHANMUGAM, G (reprint author), LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803, USA. NR 23 TC 7 Z9 7 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 FEB 20 PY 1991 VL 368 IS 2 BP 580 EP 584 DI 10.1086/169722 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX185 UT WOS:A1991EX18500027 ER PT J AU DEARBORN, D GRIEST, K RAFFELT, G AF DEARBORN, D GRIEST, K RAFFELT, G TI WINDOW FOR THE DARK MATTER SOLUTION TO THE SOLAR NEUTRINO PROBLEM SO ASTROPHYSICAL JOURNAL LA English DT Article DE DARK MATTER; ELEMENTARY PARTICLES; NEUTRINOS; SUN, INTERIOR ID INTERACTING MASSIVE PARTICLES; ENERGY-TRANSPORT; SUN; CANDIDATES; CAPTURE; LIMITS; MODELS; OSCILLATIONS; EVAPORATION; COSMION AB The existence of dark matter particles (cosmions) inside the Sun has been suggested as an explanation for the disagreement between measured and theoretical solar neutrino fluxes. We use the new theoretical results on cosmion capture, evaporation, and energy transport, as well as a modern solar evolution code, to estimate accurately the range of cosmion masses and cross sections which can solve the solar neutrino problem. We find a range somewhat smaller than previously estimated. Including new results from a silicon direct detection experiment, only two extremely small regions of parameter space remain acceptable for the coherent spin-independent cross sections often considered. Cosmions which interact dominantly with hydrogen (spin-dependent interactions) are unaffected by current direct detection searches and remain viable for masses between roughly 2 and 7 GeV and cross sections on protons between roughly 10(-36) and 10(-33.5) cm2. C1 UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. MAX PLANCK INST PHYS & ASTROPHYS,W-8000 MUNICH 40,GERMANY. RP DEARBORN, D (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 46 TC 26 Z9 26 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 FEB 20 PY 1991 VL 368 IS 2 BP 626 EP 632 DI 10.1086/169729 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX185 UT WOS:A1991EX18500034 ER PT J AU WOOSLEY, SE HOFFMAN, RD AF WOOSLEY, SE HOFFMAN, RD TI CO-57 AND TI-44 PRODUCTION IN SN-1987A SO ASTROPHYSICAL JOURNAL LA English DT Article ID SN 1987A AB A survey of parameterized explosive silicon burning is carried out in order to limit the range of allowed masses of Co-57 produced by SN 1987A. The most likely value is between 0.5 and 2.5 times that implied by a solar ratio for Fe-57/Fe-56. Values more than 4 and less than one-third times the solar ratio would pose very severe problems for the theory of stellar nucleosynthesis, implying, for example, that Fe-56 was not the dominant iron group isotope or that no electron capture occurred during oxygen burning. Though dependent somewhat on the neutron excess, the Fe-57 yield is most sensitive to the occurrence of an alpha-rich freeze-out. An accurate measurement of the Fe-57 yield, as reflected observationally by the current abundance of radioactive Co-57, is thus an important constraint upon the supernova explosion mechanism. The abundance of Ti-44, another nucleus produced exclusively in the alpha-rich freeze-out, cannot be much greater than that implied by the solar ratio of Ca-44/Fe-56. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,GEN STUDIES GRP,LIVERMORE,CA 94550. SAN FRANCISCO STATE UNIV,DEPT PHYS & ASTRON,SAN FRANCISCO,CA 94132. RP WOOSLEY, SE (reprint author), UNIV CALIF SANTA CRUZ,UNIV CALIF OBSERV,LICK OBSERV,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064, USA. NR 19 TC 56 Z9 56 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 FEB 20 PY 1991 VL 368 IS 2 BP L31 EP L34 DI 10.1086/185941 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX186 UT WOS:A1991EX18600003 ER PT J AU PETERSEN, JN DAVISON, BH SCOTT, CD AF PETERSEN, JN DAVISON, BH SCOTT, CD TI MINIMIZING THE ERRORS ASSOCIATED WITH THE DETERMINATION OF EFFECTIVE DIFFUSION-COEFFICIENTS WHEN USING SPHERICAL CELL IMMOBILIZATION MATRICES SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Note ID CALCIUM ALGINATE GEL; BEADS AB Gel materials are often used to entrap biological catalysts. Several experimental methods have been proposed to estimate the diffusion coefficient of important chemical species within these materials. An error analysis for the bead method was performed and, contrary to previously reported results, when proper experimental conditions were employed, the error associated with the bead method was similar to that obtained using the other common methods. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RP PETERSEN, JN (reprint author), WASHINGTON STATE UNIV,DEPT CHEM ENGN,PULLMAN,WA 99164, USA. RI Petersen, James/B-8924-2008; Davison, Brian/D-7617-2013 OI Davison, Brian/0000-0002-7408-3609 NR 8 TC 9 Z9 9 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD FEB 20 PY 1991 VL 37 IS 4 BP 386 EP 388 DI 10.1002/bit.260370414 PG 3 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA EU687 UT WOS:A1991EU68700013 PM 18597382 ER PT J AU KIM, IK SOMORJAI, GA KIM, YG AF KIM, IK SOMORJAI, GA KIM, YG TI PREPARATION AND CHARACTERIZATION OF MGO DOPED FE2O3 SEMICONDUCTIVE ELECTRODES FOR WATER PHOTODISSOCIATION SO BULLETIN OF THE KOREAN CHEMICAL SOCIETY LA English DT Article ID PHOTOELECTROLYSIS; HYDROGEN; SI AB The preparation and characterization of semiconductive electrodes of MgO doped Fe2O3 were investigated. Pellets of MgO doped Fe2O3 were sintered at high temperatures between 1300-degrees-C and 1400-degrees-C and quenched rapidly in distilled water. The surfaces were analyzed by X-ray diffraction and scanning Auger electron spectroscopy. The surfaces of pellets contained both corundum structure (Fe2O3) and spinel structure (Mg(x)Fe(3-x)O4). Electrodes made of this material gave comparable anodic and cathodic photocurrents under illumination. The cathodic and anodic photocurrent on these photoelectrodes were verified high at 5-10 wt. percent that is critical doping amounts. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP KIM, IK (reprint author), WONKWANG UNIV,DEPT CHEM,IRI CITY 570749,SOUTH KOREA. RI Kim, Youn-Geun/C-3461-2008 OI Kim, Youn-Geun/0000-0002-5936-6520 NR 19 TC 0 Z9 0 U1 0 U2 0 PU KOREAN CHEMICAL SOC PI SEOUL PA 635-4 YEOGSAM-DONG, KANGNAM-GU, SEOUL 135-703, SOUTH KOREA SN 0253-2964 J9 B KOR CHEM SOC JI Bull. Korean Chem. Soc. PD FEB 20 PY 1991 VL 12 IS 1 BP 13 EP 17 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA FA546 UT WOS:A1991FA54600008 ER PT J AU CARRADO, KA THIYAGARAJAN, P WINANS, RE BOTTO, RE AF CARRADO, KA THIYAGARAJAN, P WINANS, RE BOTTO, RE TI HYDROTHERMAL CRYSTALLIZATION OF PORPHYRIN-CONTAINING LAYER SILICATES SO INORGANIC CHEMISTRY LA English DT Article ID CLAYS AB Porphyrins and metalloporphyrins have been demonstrated as organic templates in the hydrothermal crystallization of layered silicate smectite clays. Two water-soluble free-base porphyrins, tetrakis(N-methyl-4-pyridiniumyl)porphyrin (TMPyP) and tetrakis(N,N,N-trimethyl-4-aniliniumyl)porphyrin (TAP), along with metallo derivatives like Fe(III)TAP, were utilized as their chloride salts. Aqueous gels consisting of a 0.0166:0.20:1.00:1.52 porphyrin:LiF:Mg(OH)2:SiO2 molar ratio heated at reflux temperature crystallized synthetic porphyrin-containing hectorite clays in just 2 days. X-ray powder diffraction (XRD) gave (001) reflections of 15.0, 16.7, and 16.4 angstrom for TMPyP-, TAP-, and FeTAP-hectorite, respectively, indicating that the organic macrocycles are intercalated parallel between the clay layers. Microanalysis data and UV-visible diffuse reflectance (DR) absorption spectra reveal that the porphyrin is incorporated intact. XRD and DR spectra also reveal that the free-base forms of the porphyrins dominate in hydrothermal crystallization products, while in ion-exchanged products the dication forms predominate. Small-angle neutron scattering (SANS) was used to follow the crystallization of these systems and to analyze interactions that exist when porphyrin is reacted with silica sol and magnesium hydroxide alone. Guinier analysis of the scattering curves yields structural information about the growth process of the clay system. Random network structures are observed for the porphyrin-silica system. C1 ARGONNE NATL LAB,DIV INTENSE PULSED NEUTRON SOURCE,ARGONNE,IL 60439. RP CARRADO, KA (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S LASS AVE,ARGONNE,IL 60439, USA. NR 19 TC 65 Z9 69 U1 1 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD FEB 20 PY 1991 VL 30 IS 4 BP 794 EP 799 DI 10.1021/ic00004a034 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EY443 UT WOS:A1991EY44300034 ER PT J AU CALLIS, LB BAKER, DN BLAKE, JB LAMBETH, JD BOUGHNER, RE NATARAJAN, M KLEBESADEL, RW GORNEY, DJ AF CALLIS, LB BAKER, DN BLAKE, JB LAMBETH, JD BOUGHNER, RE NATARAJAN, M KLEBESADEL, RW GORNEY, DJ TI PRECIPITATING RELATIVISTIC ELECTRONS - THEIR LONG-TERM EFFECT ON STRATOSPHERIC ODD NITROGEN LEVELS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOLAR PROTON EVENTS; MIDDLE ATMOSPHERE; NITRIC-OXIDE; PARTICLE-PRECIPITATION; OZONE PHOTOCHEMISTRY; LIMS OBSERVATIONS; NIMBUS-7 DATA; MESOSPHERE; NO2; TRANSPORT AB Using electron count rate data at geostationary orbit, daily energy spectra, extending from 30 keV to 15 MeV, have been developed for trapped relativistic electrons at 6.6 R(E). These spectra have been used to model the flux of these electrons into the atmosphere at 120 km. Energy deposition calculations permit daily sources of HO(x) and NO(y) to be calculated at auroral and subauroral latitudes due to relativistic electron precipitation (REP) for the period June 13, 1979, through June 4, 1988. Both short-term and long-term source variations are quite large over the period considered. The long-term variation of the NO(y) source is found to reach a maximum in late 1984 and early 1985, with significant declines thereafter. Daily Solar Backscattered Ultraviolet (SBUV) O3 data show a significant response to these precipitation events. Two-dimensional model calculations have been carried out for the period 1979 to 1990 with REP effects included through June 4, 1988. Results suggest that globally integrated NO(y) has increased by 35-40% from 1979 to early 1985 with declines thereafter. The largest long-term increases are found in the lower stratosphere at the high latitudes. Comparisons of Limb Infrared Monitor of the Stratosphere (LIMS), Solar Mesospheric Explorer (SME), Stratospheric Aerosol and Gas Experiment (SAGE), and SAGE II NO2 data are consistent with these calculations. The results suggest that a significant contribution to the anomalously large and unexplained global O3 declines between 1979 and 1985 has been made by the catalytic destruction of O3 by odd nitrogen in the lower stratosphere at mid to high latitudes. The results also provide evidence for a clear and strong linkage between solar variability, the state of the magnetosphere, and the chemical climatological state of the middle and lower atmosphere. C1 ST SYST CORP, HAMPTON, VA USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. AEROSPACE CORP, EL SEGUNDO, CA 90245 USA. UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. RP CALLIS, LB (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. NR 89 TC 79 Z9 80 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1991 VL 96 IS D2 BP 2939 EP 2976 DI 10.1029/90JD02184 PG 38 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EZ657 UT WOS:A1991EZ65700011 ER PT J AU BRITT, RD SAUER, K KLEIN, MP KNAFF, DB KRIAUCIUNAS, A YU, CA YU, L MALKIN, R AF BRITT, RD SAUER, K KLEIN, MP KNAFF, DB KRIAUCIUNAS, A YU, CA YU, L MALKIN, R TI ELECTRON-SPIN ECHO ENVELOPE MODULATION SPECTROSCOPY SUPPORTS THE SUGGESTED COORDINATION OF 2 HISTIDINE LIGANDS TO THE RIESKE FE-S CENTERS OF THE CYTOCHROME-B6F COMPLEX OF SPINACH AND THE CYTOCHROME-BC1 COMPLEXES OF RHODOSPIRILLUM-RUBRUM, RHODOBACTER-SPHAEROIDES R-26, AND BOVINE HEART-MITOCHONDRIA SO BIOCHEMISTRY LA English DT Article ID IRON-SULFUR PROTEIN; AMINO-ACID-SEQUENCE; PHTHALATE DIOXYGENASE; 2FE-2S CLUSTERS; N-COORDINATION; RHODOPSEUDOMONAS-SPHAEROIDES; QUADRUPOLE-RESONANCE; NUCLEOTIDE-SEQUENCE; RESPIRATORY-CHAIN; BC1 COMPLEX AB Electron spin echo envelope modulation (ESEEM) experiments performed on the Rieske Fe-S clusters of the cytochrome b6f complex of spinach chloroplasts and of the cytochrome bc1 complexes of Rhodospirillum rubrum, Rhodobacter sphaeroides R-26, and bovine heart mitochondria show modulation components resulting from two distinct classes of N-14 ligands. At the g = 1.92 region of the Rieske EPR spectrum of the cytochrome b6f complex, the measured hyperfine couplings for the two classes of coupled nitrogens are A1 = 4.6 MHz and A2 = 3.8 MHz. Similar couplings are observed for the Rieske centers in the three cytochrome bc1 complexes. These ESEEM results indicate a nitrogen coordination environment for these Rieske Fe-S centers that is similar to that of the Fe-S cluster of a bacterial dioxygenase enzyme with two coordinated histidine ligands [Gurbiel, R. J., Batie, C. J., Sivaraja, M., True, A. E., Fee, J. A., Hoffman, B. M., & Ballou, D. P. (1989) Biochemistry 28, 4861-4871]. The Rieske Fe-S cluster lacks modulation components from a weakly coupled peptide nitrogen observed in water-soluble spinach ferredoxin. Treatment with the quinone analogue inhibitor DBMIB causes a shift in the Rieske EPR spectrum to g = 1.95 with no alteration in the magnetic couplings to the two nitrogen atoms. However, the ESEEM pattern of the DBMIB-altered Rieske EPR signal shows evidence of an additional weakly coupled nitrogen similar to that observed in the spinach ferredoxin ESEEM patterns. C1 TEXAS TECH UNIV,DEPT CHEM & BIOCHEM,LUBBOCK,TX 79409. OKLAHOMA STATE UNIV,DEPT BIOCHEM,STILLWATER,OK 74078. UNIV CALIF BERKELEY,DEPT PLANT BIOL,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CHEM BIODYNAM LAB,BERKELEY,CA 94720. FU NIGMS NIH HHS [GM 20571, GM 30721] NR 59 TC 110 Z9 111 U1 1 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 FEB 19 PY 1991 VL 30 IS 7 BP 1892 EP 1901 DI 10.1021/bi00221a023 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EY207 UT WOS:A1991EY20700023 PM 1847076 ER PT J AU SELA, I WATKINS, DE LAURICH, BK SMITH, DL SUBBANNA, S KROEMER, H AF SELA, I WATKINS, DE LAURICH, BK SMITH, DL SUBBANNA, S KROEMER, H TI EXCITONIC OPTICAL NONLINEARITY INDUCED BY INTERNAL FIELD SCREENING IN (211) ORIENTED STRAINED-LAYER SUPERLATTICES SO APPLIED PHYSICS LETTERS LA English DT Article ID GROWTH AXIS AB The nonlinear optical properties of a new class of strained-layer superlattices (intrinsic Stark effect superlattices) have been investigated. Specifically, we have compared the nonlinear transmission of Ga1-xIn(x)As-GaAs strained-layer superlattices grown along the (211) axis to identical superlattices grown along the (100) axis, and found that the optical nonlinearity in the (211) sample is about one order of magnitude greater than in the (100) sample. A blue shift of the exciton resonance and an increase in the exciton absorption strength in the (211) sample with increasing light intensity was observed (attributed to screening of the intrinsic Stark effect fields by photogenerated carriers), resulting in the stronger optical nonlinearity. The maximum of the nonlinear absorption index, \alpha-2\, in the (211) sample was 54 cm/W (\Im chi-3\ = 0.33 esu) whereas in the (100) sample the maximum of \alpha-2\ was 6.9 cm/W (\Im chi-3\ = 0.042 esu). The measured carrier recovery time in both samples was 2 ns. C1 UNIV CALIF SANTA BARBARA,ECE,SANTA BARBARA,CA 93106. RP SELA, I (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 10 TC 64 Z9 64 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 FEB 18 PY 1991 VL 58 IS 7 BP 684 EP 686 DI 10.1063/1.104568 PG 3 WC Physics, Applied SC Physics GA EX595 UT WOS:A1991EX59500008 ER PT J AU TIDJANI, ME GRONSKY, R KINGSTON, JJ WELLSTOOD, FC CLARKE, J AF TIDJANI, ME GRONSKY, R KINGSTON, JJ WELLSTOOD, FC CLARKE, J TI HETEROEPITAXIAL YBA2CU3O7-X-SRTIO3-YBA2CU3O7-X TRILAYERS EXAMINED BY TRANSMISSION ELECTRON-MICROSCOPY SO APPLIED PHYSICS LETTERS LA English DT Article ID INTERFACES AB We report high-resolution transmission electron microscopy and electron diffraction studies of the heteroepitaxial superconductor-insulator-superconductor system YBa2Cu3O7-x-SrTiO3-YBa2Cu3O7-x deposited on polished (001) MgO substrates by in situ laser ablation. The resulting films grow epitaxially and consistently preserve a parallel orientation between the close-packed (001) YBa2Cu3O7-x planes and (001)SrTiO3 planes over the entire trilayer, even in the presence of ledges or steps along vicinal interfaces. Although the interface regions showed strain occasionally relieved by stacking faults, they were free of disorder and any evidence of impurity phases. The observed epitaxial growth is very likely responsible for the excellent electrical properties found in similarly constructed multilayer interconnects. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR ADV MAT,BERKELEY,CA 94720. RP TIDJANI, ME (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. RI Joint Quantum Institute, NIST/UMD/H-4494-2011 NR 12 TC 23 Z9 23 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 18 PY 1991 VL 58 IS 7 BP 765 EP 767 DI 10.1063/1.104541 PG 3 WC Physics, Applied SC Physics GA EX595 UT WOS:A1991EX59500035 ER PT J AU HUGHES, RJ HOLZSCHEITER, MH AF HUGHES, RJ HOLZSCHEITER, MH TI CONSTRAINTS ON THE GRAVITATIONAL PROPERTIES OF ANTIPROTONS AND POSITRONS FROM CYCLOTRON-FREQUENCY MEASUREMENTS SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANTIMATTER; GRAVITY AB Tests of the weak equivalence principle for antiprotons and positrons are inferred from the results of particle-antiparticle cyclotron-frequency comparisons. The potential improvements from future, higher-precision experiments are discussed. RP HUGHES, RJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,P-15,LOS ALAMOS,NM 87545, USA. NR 30 TC 33 Z9 33 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 18 PY 1991 VL 66 IS 7 BP 854 EP 857 DI 10.1103/PhysRevLett.66.854 PG 4 WC Physics, Multidisciplinary SC Physics GA EX578 UT WOS:A1991EX57800003 ER PT J AU STREETS, K BOCA, G GEORGIOPOULOS, C GOLDMAN, JH HAGOPIAN, S HAGOPIAN, V JOHNSON, KF KAPLAN, DM LEVINTHAL, D LOPEZ, F SAWYER, HL STREETS, J WHITE, HB YOUNG, C CRISLER, M LATHROP, A PORDES, S VOLK, J CUMMINGS, M GUSTAFSON, HR AF STREETS, K BOCA, G GEORGIOPOULOS, C GOLDMAN, JH HAGOPIAN, S HAGOPIAN, V JOHNSON, KF KAPLAN, DM LEVINTHAL, D LOPEZ, F SAWYER, HL STREETS, J WHITE, HB YOUNG, C CRISLER, M LATHROP, A PORDES, S VOLK, J CUMMINGS, M GUSTAFSON, HR TI ATOMIC-WEIGHT DEPENDENCE OF THE PRODUCTION OF HADRON PAIRS BY 800-GEV/C PROTONS ON NUCLEAR TARGETS SO PHYSICAL REVIEW LETTERS LA English DT Article ID LARGE TRANSVERSE-MOMENTUM; LEPTON SCATTERING; NUMBER DEPENDENCE; COLLISIONS AB Fermilab experiment 711 has investigated proton-nucleus collisions in which two high-transverse-momentum hadrons are produced forming high-mass ++, +-, and -- charged states, using an 800-GeV/c proton beam on targets of beryllium, aluminum, iron, and tungsten. Our data cover the range in dihadron mass from 6 to 15 GeV/c2. We show here that the dependence of the cross section on atomic weight A can be parametrized as A-alpha, where alpha = 1.043 +/- 0.011 (stat) +/- 0.025 (syst), and is independent of the charge state of the dihadron system. C1 FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV MICHIGAN,ANN ARBOR,MI 48109. OI Sawyer, Lee/0000-0001-8295-0605 NR 19 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 18 PY 1991 VL 66 IS 7 BP 864 EP 867 DI 10.1103/PhysRevLett.66.864 PG 4 WC Physics, Multidisciplinary SC Physics GA EX578 UT WOS:A1991EX57800006 ER PT J AU BONCHE, P KRIEGER, SJ WEISS, MS DOBACZEWSKI, J FLOCARD, H HEENEN, PH AF BONCHE, P KRIEGER, SJ WEISS, MS DOBACZEWSKI, J FLOCARD, H HEENEN, PH TI OCTUPOLE SOFTNESS OF SUPERDEFORMED PB-194 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPIN AB Using parity projection and the generator-coordinate method we investigate the left-right-asymmetric softness of the superdeformed minimum of Pb-194. The collective wave functions exhibit large octupole dispersions. Our calculation suggests that above the ground-state superdeformed band there should exist a negative-parity band of similar quadrupole deformation with an excitation energy close to 2 MeV. C1 UNIV WARSAW,INST THEORET PHYS,PL-00681 WARSAW,POLAND. INST PHYS NUCL,DIV PHYS THEOR,F-91406 ORSAY,FRANCE. UNIV LIBRE BRUXELLES,SERV PHYS NUCL THEOR,B-1050 BRUSSELS,BELGIUM. CEA,SERV PHYS THEOR,DIRECT SCI MAT,F-91191 GIF SUR YVETTE,FRANCE. RP BONCHE, P (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 28 TC 51 Z9 51 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 18 PY 1991 VL 66 IS 7 BP 876 EP 879 DI 10.1103/PhysRevLett.66.876 PG 4 WC Physics, Multidisciplinary SC Physics GA EX578 UT WOS:A1991EX57800009 ER PT J AU ROJO, AG CANRIGHT, GS AF ROJO, AG CANRIGHT, GS TI ORDERING OF CHIRALITY FOR MANY PLANES OF ANYONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID 2 DIMENSIONS; QUANTUM-MECHANICS; STATISTICS; FLUX AB We consider the effect of interplane coupling on the energetics of the relative sign of statistics of anyons in adjacent planes. We offer qualitative arguments as well as numerical results which support the idea that opposing chirality (i.e., "antiferromagnetic" order of the statistics) is favored over a wide range of interplane coupling V - including both attractive and repulsive interactions between planes. We argue that our results apply to the normal (nonsuperfluid) phase in the thermodynamic limit. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP ROJO, AG (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 18 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 18 PY 1991 VL 66 IS 7 BP 949 EP 952 DI 10.1103/PhysRevLett.66.949 PG 4 WC Physics, Multidisciplinary SC Physics GA EX578 UT WOS:A1991EX57800028 ER PT J AU BEGAY, F AF BEGAY, F TI STRONG LANGMUIR TURBULENCE IN LASER-CREATED PLASMAS SO PHYSICS LETTERS A LA English DT Article ID STIMULATED RAMAN-SCATTERING; HIGH-FREQUENCY ENERGY; ELECTROMAGNETIC-WAVE; DECAY INSTABILITY; DISSIPATION; RESONANCE AB Concepts of strong Langmuir turbulence are used (1) to interpret experimental results from laser-matter interaction experiments performed at Los Alamos and Osaka University and (2) to discuss the anomalous transport of absorbed laser energy into electron heating and acceleration. We derived new heated electron "temperature" scaling laws which employ results from strong turbulence models advanced by Sagdeev et al. and Nicholson et al. Agreement between the Los Alamos CO2 and the Osaka glass laser-target data and proposed analytic model data confirm the validity of the new heated electron "temperature" scaling laws. Computational results for other plasma parameters such as absorption coefficient and maximum electron energy are also presented. We develop design criteria to minimize plasma turbulence effects for laser-target experiments. RP BEGAY, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545, USA. NR 32 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD FEB 18 PY 1991 VL 153 IS 1 BP 27 EP 34 DI 10.1016/0375-9601(91)90356-D PG 8 WC Physics, Multidisciplinary SC Physics GA EY506 UT WOS:A1991EY50600006 ER PT J AU GOUGEON, P MCCARLEY, RE AF GOUGEON, P MCCARLEY, RE TI STRUCTURE OF NDMO8O14 CONTAINING THE NEW MO8 CLUSTER SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article AB Neodymium octamolybdate, NdMo8O14, M(r) = 1135.75, orthorhombic, Aba2, a = 9.209 (3), b = 10.008 (2), c = 11.143 (4) angstrom, V = 1026.9 (6) angstrom 3, Z = 4, D(x) = 7.346 g cm-3, lambda (Mo K-alpha) = 0.71073 angstrom, mu = 143.0 cm-1, F(000) = 2032, T = 295 K, R = 0.021 for 1079 observed reflections. The title compound contains the new Mo8 cluster based on a distorted octahedron capped by two additional Mo atoms. The Mo8 clusters are connected by bridging oxygens and arranged in layers parallel to the bc plane. The Nd atoms located within the cluster layers are surrounded by 12 oxygens at distances ranging from 2.362 (8) to 3.139 (6) angstrom. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP GOUGEON, P (reprint author), UNIV RENNES 1,CHIM MINERALE LAB B,CNRS,URA 254,AVE GEN LECLERC,F-35042 RENNES,FRANCE. NR 12 TC 31 Z9 31 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD FEB 15 PY 1991 VL 47 BP 241 EP 244 DI 10.1107/S0108270190008666 PN 2 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FA122 UT WOS:A1991FA12200002 ER PT J AU JARVINEN, GD ZOZULIN, AJ LARSON, EM RYAN, RR AF JARVINEN, GD ZOZULIN, AJ LARSON, EM RYAN, RR TI STRUCTURE OF BIS(4-BENZOYL-2,4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONATO-O,O')DINI TRATOBIS(TRIPHENYLPHOSPHINE OXIDE-O)THORIUM(IV) SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article AB [Th(C17H13N2O2)2(NO3)2(C18H15OP)2], M(r) = 1467, orthorhombic, Pcan, a = 11.619 (10), b = 23.721 (10), c = 25.243 (4) angstrom, V = 6957.33 angstrom 3, Z = 4 D(x) = 1.40 g cm-3, lambda-(Mo K-alpha) = 0.71069 angstrom, mu = 23.2 cm-1, F(000) = 2936, T = 298 K, R = 0.058 for 2547 reflections with I greater-than-or-equal-to 2-sigma-(I). The crystal is composed of discrete molecules containing a thorium ion coordinated to ten O atoms from two bidentate benzoyl pyrazolone anions, two bidentate nitrate anions, and two triphenylphosphine oxide molecules. RP JARVINEN, GD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 11 TC 7 Z9 10 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD FEB 15 PY 1991 VL 47 BP 262 EP 264 DI 10.1107/S0108270190002177 PN 2 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FA122 UT WOS:A1991FA12200010 ER PT J AU BRNICEVIC, N MCCARLEY, RE HILSENBECK, S KOJICPRODIC, B AF BRNICEVIC, N MCCARLEY, RE HILSENBECK, S KOJICPRODIC, B TI STRUCTURE OF [NA2(CH3OH)9][TA6CL12(OCH3)6].3CH3OH SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID POLYNUCLEAR METAL-HALIDES; CHEMISTRY; NIOBIUM; CRYSTAL AB Tri-mu-methanol-bis(trimethanolsodium) dodeca-mu-chloro-hexamethoxy-1KO,2KO,3KO,4KO,5KO,6KO-octahedro-hexatantalate methanol solvate (1/3), [Na2(CH3OH)9][Ta6Cl12(OCH3)6].3CH3OH, M(r) = 2127.82, hexagonal, P6(3)/m, a = 11.696 (1), c = 23.110 (3) angstrom, V = 2738 (1) angstrom 3, Z = 2, D(x) = 2.581 g cm-3, lambda-(Mo K-alpha) = 0.71073 angstrom, mu = 124.65 cm-1, F(000) = 1964, T = 143 K, final R = 0.045, wR = 0.053 for 735 observed reflections with I > 3-sigma-(I). The crystal structure reveals a dimeric cation, [Na2(mu-CH3OH)3(CH3OH)6]2+ with octahedral environment about sodium (Na-O bridging, 2.45 angstrom; Na-O terminal, 2.37 angstrom). The octahedral cluster unit, [Ta6Cl12(OCH3)6]2- exhibits Ta-Ta distances of 2.994 (2) and 2.975 (2) angstrom with Ta-Cl from 2.434 (6) to 2.456 (5) angstrom (all bridging). Six methoxo groups are in terminal positions with a Ta-O distance of 2.04 (2) angstrom. The structure is held together by a network of hydrogen bonds between the cations, cluster anions and solvent (methanol) molecules. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP BRNICEVIC, N (reprint author), RUDJER BOSKOVIC INST,YU-41000 ZAGREB,YUGOSLAVIA. NR 9 TC 18 Z9 18 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD FEB 15 PY 1991 VL 47 BP 315 EP 318 DI 10.1107/S0108270190008228 PN 2 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FA122 UT WOS:A1991FA12200029 ER PT J AU MCLUCKEY, SA VANBERKEL, GJ GLISH, GL HUANG, EC HENION, JD AF MCLUCKEY, SA VANBERKEL, GJ GLISH, GL HUANG, EC HENION, JD TI ION SPRAY LIQUID-CHROMATOGRAPHY ION TRAP MASS-SPECTROMETRY DETERMINATION OF BIOMOLECULES SO ANALYTICAL CHEMISTRY LA English DT Article ID CAPILLARY ZONE ELECTROPHORESIS; ELECTROSPRAY IONIZATION INTERFACE; AEROSOL GENERATION INTERFACE; MULTIPLY CHARGED IONS; PERFORMANCE; PEPTIDES; SPECTRA AB The first on-line coupling of microbore high-performance liquid chromatography (HPLC) with an ion trap mass spectrometer equipped for sampling ions formed by electrospray ionization at atmospheric pressure is reported. A pneumatically assisted electrospray (ion spray) liquid chromatograph/mass spectrometer interface was used to couple reversed-phase, linear solvent gradient separations of biologically important compounds, including peptides and proteins, with the ion trap mass spectrometer. Initial gradient HPLC conditions consisting of 95% aqueous 0.15% trifluoroacetic acid in acetonitrile maintained at a flow of 40-mu-L/min were used with the system. Useful ion current profiles for levels down to 2.5 pmol per component of tryptic peptides and 0.3 pmol of injected human serum albumin (HSA) were obtained under these conditions. Full-scan mass spectra of multiply protonated molecules are shown for the target compounds at these levels. On-line HPLC/mass spectrometry (MS) molecular weight determinations for cytochrome c, HSA, and myoglobin are shown as well as LC/MS2 and LC/MS3 determinations of selected tryptic peptides in a protein tryptic digest. These applications demonstrate the analytical potential for the ion trap mass spectrometer combined with HPLC through its high detection sensitivity and MS(n) capability. C1 CORNELL UNIV,NEW YORK STATE COLL VET MED,DRUG TESTING & TOXICOL DIAGNOST LAB,ITHACA,NY 14850. RP MCLUCKEY, SA (reprint author), OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831, USA. RI McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 49 TC 108 Z9 109 U1 3 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 15 PY 1991 VL 63 IS 4 BP 375 EP 383 DI 10.1021/ac00004a015 PG 9 WC Chemistry, Analytical SC Chemistry GA EX235 UT WOS:A1991EX23500016 ER PT J AU PANG, HM WIEDERIN, DR HOUK, RS YEUNG, ES AF PANG, HM WIEDERIN, DR HOUK, RS YEUNG, ES TI HIGH-REPETITION-RATE LASER ABLATION FOR ELEMENTAL ANALYSIS IN AN INDUCTIVELY COUPLED PLASMA WITH ACOUSTIC-WAVE NORMALIZATION SO ANALYTICAL CHEMISTRY LA English DT Article ID ATOMIC-EMISSION-SPECTROMETRY; MASS-SPECTROMETRY; SOLID SAMPLES; VAPORIZATION; PLUMES; SIGNAL AB A laser ablation system with 100-Hz repetition rate for direct elemental analysis of solids by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) is described. Detection limits of 12-mu-g/g and 4 ng/g for ICP-AES and ICP-MS, respectively, are observed. These improvements are attributed to the use of low vaporization laser powers (50 mJ), which may produce a more uniform and finer spray. Precision is improved by a factor of 2 or more by averaging over a larger number of laser pulses within the same measurement and by normalizing the emission signal to the amplitude of the acoustic wave generated during the ablation process. C1 US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. NR 20 TC 61 Z9 64 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 15 PY 1991 VL 63 IS 4 BP 390 EP 394 DI 10.1021/ac00004a017 PG 5 WC Chemistry, Analytical SC Chemistry GA EX235 UT WOS:A1991EX23500018 ER PT J AU CLASTER, S WHITE, E WOOLWORTH, V QUINTANILHA, A AF CLASTER, S WHITE, E WOOLWORTH, V QUINTANILHA, A TI DEGRADATION OF ERYTHROCYTE GLYCOPHORIN RESULTS IN INCREASED MEMBRANE-BOUND HEMOGLOBIN SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Article C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RP CHILDRENS HOSP, OAKLAND RES INST, 747 52ND ST, OAKLAND, CA 94609 USA. RI Quintanilha, Alexandre/L-5371-2013 OI Quintanilha, Alexandre/0000-0001-8544-0061 FU NHLBI NIH HHS [HL20985] NR 26 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0003-9861 EI 1096-0384 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD FEB 15 PY 1991 VL 285 IS 1 BP 147 EP 152 DI 10.1016/0003-9861(91)90342-G PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA EV516 UT WOS:A1991EV51600022 PM 1990974 ER PT J AU WILLMAN, CL STEWART, CC LONGACRE, TL HEAD, DR HABBERSETT, R ZIEGLER, SF PERLMUTTER, RM AF WILLMAN, CL STEWART, CC LONGACRE, TL HEAD, DR HABBERSETT, R ZIEGLER, SF PERLMUTTER, RM TI EXPRESSION OF THE C-FGR AND HCK PROTEIN-TYROSINE KINASES IN ACUTE MYELOID LEUKEMIC BLASTS IS ASSOCIATED WITH EARLY COMMITMENT AND DIFFERENTIATION EVENTS IN THE MONOCYTIC AND GRANULOCYTIC LINEAGES SO BLOOD LA English DT Article ID CELL-SURFACE-ANTIGENS; GENE HCK; SIGNAL TRANSDUCTION; CATALYTIC DOMAINS; FLOW-CYTOMETRY; ACTIVATION; ONCOGENE; P56LCK; INDUCTION; RECEPTOR C1 UNIV NEW MEXICO, SCH MED, DEPT PATHOL, ALBUQUERQUE, NM 87131 USA. UNIV CALIF LOS ALAMOS SCI LAB, NATL FLOW CYTOMETRY RESOURCE, LOS ALAMOS, NM 87544 USA. ST JUDE CHILDRENS RES HOSP, MEMPHIS, TN 38101 USA. UNIV WASHINGTON, SCH MED, HOWARD HUGHES MED INST, SEATTLE, WA 98195 USA. SW ONCOL GRP LEUKEMIA BIOL PROGRAM, SAN ANTONIO, TX USA. RP WILLMAN, CL (reprint author), UNIV NEW MEXICO, CTR CANC, SCH MED, DEPT CELL PATHOL, 900 CAMINO DE SALUD NE, ALBUQUERQUE, NM 87131 USA. FU NCI NIH HHS [CA-45682, CA-32102]; NIDDK NIH HHS [K11-DK-01284] NR 28 TC 46 Z9 47 U1 0 U2 0 PU AMER SOC HEMATOLOGY PI WASHINGTON PA 1900 M STREET. NW SUITE 200, WASHINGTON, DC 20036 USA SN 0006-4971 J9 BLOOD JI Blood PD FEB 15 PY 1991 VL 77 IS 4 BP 726 EP 734 PG 9 WC Hematology SC Hematology GA EX922 UT WOS:A1991EX92200007 PM 1825181 ER PT J AU BEGUIN, Y CLEMONS, GK ORIS, R FILLET, G AF BEGUIN, Y CLEMONS, GK ORIS, R FILLET, G TI CIRCULATING ERYTHROPOIETIN LEVELS AFTER BONE-MARROW TRANSPLANTATION - INAPPROPRIATE RESPONSE TO ANEMIA IN ALLOGENEIC TRANSPLANTS SO BLOOD LA English DT Article ID RECOMBINANT HUMAN ERYTHROPOIETIN; BFU-E; HEMATOPOIETIC PROGENITORS; SERUM ERYTHROPOIETIN; CFU-GM; RADIOIMMUNOASSAY; HEMODIALYSIS; PRECURSORS; INHIBITION; INCREASE C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELLULAR & MOLEC BIOL,BERKELEY,CA 94720. RP BEGUIN, Y (reprint author), CHU SART TILMAN,DEPT HEMATOL,B-4000 LIEGE,BELGIUM. FU NHLBI NIH HHS [HL22469] NR 21 TC 84 Z9 85 U1 0 U2 0 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 SN 0006-4971 J9 BLOOD JI Blood PD FEB 15 PY 1991 VL 77 IS 4 BP 868 EP 873 PG 6 WC Hematology SC Hematology GA EX922 UT WOS:A1991EX92200026 PM 1847085 ER PT J AU DARSEY, JA NOID, DW UPADHYAYA, BR AF DARSEY, JA NOID, DW UPADHYAYA, BR TI APPLICATION OF NEURAL NETWORK COMPUTING TO THE SOLUTION FOR THE GROUND-STATE EIGENENERGY OF 2-DIMENSIONAL HARMONIC-OSCILLATORS SO CHEMICAL PHYSICS LETTERS LA English DT Article AB In this Letter, we teach a neural network the solution of the Schrodinger equation for some model potential energy functions. The network can then predict eigenvalues of other test cases with an error of a few percent. C1 OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. UNIV TENNESSEE,DEPT NUCL ENGN,KNOXVILLE,TN 37996. RP DARSEY, JA (reprint author), UNIV ARKANSAS,DEPT CHEM,LITTLE ROCK,AR 72204, USA. NR 7 TC 22 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 15 PY 1991 VL 177 IS 2 BP 189 EP 194 DI 10.1016/0009-2614(91)90066-I PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY252 UT WOS:A1991EY25200014 ER PT J AU CILIBERTO, S NICOLAENKO, B AF CILIBERTO, S NICOLAENKO, B TI ESTIMATING THE NUMBER OF DEGREES OF FREEDOM IN SPATIALLY EXTENDED SYSTEMS SO EUROPHYSICS LETTERS LA English DT Article ID COUPLED MAP LATTICES; COHERENT STRUCTURES; TEMPORAL INTERMITTENCY; STRANGE ATTRACTORS; WALL REGION; DYNAMICS AB Karhunen-Loeve decomposition has been used in order to compute the number of the fundamental degrees of freedom in a complex spatiotemporal dynamics. The method has been applied on experimental and numerical data. In both cases the number of degrees of freedom found by this method is very close to the fractal dimension of the attractor or the Lyapunov dimension. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. ARIZONA STATE UNIV,TEMPE,AZ 85287. RP CILIBERTO, S (reprint author), IST NAZL OTTICA,LARGO FERMI 6,I-50125 FLORENCE,ITALY. NR 24 TC 33 Z9 33 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD FEB 15 PY 1991 VL 14 IS 4 BP 303 EP 308 DI 10.1209/0295-5075/14/4/003 PG 6 WC Physics, Multidisciplinary SC Physics GA EY367 UT WOS:A1991EY36700003 ER PT J AU ALFORD, WJ HAYS, GN OHWA, M KUSHNER, MJ AF ALFORD, WJ HAYS, GN OHWA, M KUSHNER, MJ TI THE EFFECTS OF HE ADDITION ON THE PERFORMANCE OF THE FISSION-FRAGMENT EXCITED AR/XE ATOMIC XENON LASER SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BEAM AB The intrinsic power efficiency of the atomic xenon laser depends upon the electron density because of the mixing of the laser levels by electron collisions while the electron density in high-pressure particle-beam excited plasmas increases with increasing gas temperature. Therefore, in order to reduce the amount of electron collisional mixing when operating at high-energy loadings (> 100's J/1-atm) mixtures having a high-heat capacity are required. In particle-beam excited Ar/Xe mixtures, which typically yield the highest intrinsic laser efficiencies, increasing the gas pressure to increase the heat capacity is not always practical due to the high-stopping power of the gas mixture. For this reason we have experimentally and theoretically investigated adding He to Ar/Xe mixtures in studies of a fission-fragment excited atomic xenon laser. Adding He increases the heat capacity without appreciably perturbing the favourable kinetics resulting in efficient operation of the laser in Ar/Xe mixtures. We find that when adding He to Ar/Xe mixtures the dominant laser transition switches from 1.73 to 2.03-mu-m without significantly decreasing the efficiency. The laser pulse length also increases, an effect attributed to a lowering of both the electron temperature and gas temperatures. C1 UNIV ILLINOIS,DEPT ELECT & COMP ENGN OPT & DISCHARGE PHYS,1406 W GREEN ST,URBANA,IL 61801. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RI Kushner, Mark/A-7362-2008; Kushner, Mark/D-4547-2015 NR 18 TC 34 Z9 34 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 FEB 15 PY 1991 VL 69 IS 4 BP 1843 EP 1848 DI 10.1063/1.348752 PG 6 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400006 ER PT J AU WHITE, RH EDWARDS, DF RATHKOPF, JA AF WHITE, RH EDWARDS, DF RATHKOPF, JA TI HARDENING OPTICAL COATINGS TO THE EFFECTS OF X-RAYS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DIAMOND AB Analyses of the effects of x rays on optical components consisting of a metal reflecting layer, a beryllium heat sink, and a fused silica substrate were done using the computer code XRTH. These are compared with calculations for components lacking the beryllium layer. Our analyses show that the addition of the beryllium significantly hardens the system against x rays. The mechanisms for this increased hardness are elucidated by time-dependent temperature and enthalpy plots. The relative effectiveness of beryllium and diamondlike carbon heat sinks is explored. Complex designs which incorporate reflection-enhancing dielectric stacks are also discussed. Some comparisons with experiments are given. RP WHITE, RH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,L298,LIVERMORE,CA 94550, USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1991 VL 69 IS 4 BP 1901 EP 1908 DI 10.1063/1.348760 PG 8 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400014 ER PT J AU RHOADES, CE TRIPLETT, JR AF RHOADES, CE TRIPLETT, JR TI MODELING THE BEHAVIOR OF OPTICAL COATINGS IN X-RAY ENVIRONMENTS SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Calculation of heating caused by the deposition of x rays in thin-film optical coatings is complicated because the mean free path of photo- and autoionization electrons is comparable to the thin-film thickness and thus electron deposition cannot be considered local. This paper describes the modeling in the computer code XRTH of (a) x-ray deposition and transport, (b) electron production, deposition, and transport, and (c) thermal conduction and transport. X-ray transport is handled by multigroup discrete ordinates, electron transport is done by the method of characteristics, applied to the two-term spherical harmonics expansion approximation (P1) to the Spencer-Lewis transport equation, and thermal transport is computed by a Richardson extrapolation of a backward Euler solution to the heat conduction equation. Results of a few test cases and comparisons with other computer codes are presented. C1 S CUBED INC,LA JOLLA,CA 92038. RP RHOADES, CE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,L298,LIVERMORE,CA 94550, USA. NR 23 TC 1 Z9 1 U1 1 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 FEB 15 PY 1991 VL 69 IS 4 BP 1909 EP 1914 DI 10.1063/1.348761 PG 6 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400015 ER PT J AU ROBEY, HF ALBRECHT, GF FREITAS, BL AF ROBEY, HF ALBRECHT, GF FREITAS, BL TI FLOW CONDITIONING FOR IMPROVED OPTICAL PROPAGATION OF BEAMS THROUGH REGIONS BOUNDED BY SURFACES OF HIGH SOLIDITY SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB A flow conditioning system has been designed to maximize the thermal homogeneity in an enclosed region through which a laser beam must propagate. In the present application, such an enclosed region exists between the Nd:glass disks of a high average power solid-state laser amplifier. Experiments have been conducted on a test facility to quantify the magnitude of the beam losses due to thermal scattering. It is shown that the intensity of the incoherent light which is thermally scattered from this region can be reduced to less than 0.1% of the incident-beam intensity under apropriate flow and cooling conditions. RP ROBEY, HF (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 5508,L487,LIVERMORE,CA 94550, USA. NR 13 TC 2 Z9 2 U1 1 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 FEB 15 PY 1991 VL 69 IS 4 BP 1915 EP 1922 DI 10.1063/1.348762 PG 8 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400016 ER PT J AU HODGDON, ML AF HODGDON, ML TI A CONSTITUTIVE RELATION FOR HYSTERESIS IN SUPERCONDUCTORS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MODEL AB A constitutive relation consisting of a differential equation B = alpha\H\[f(H) - B] + Hg(H), where H is nonzero, and an experimentally determined condition imposed at the points where H changes sign is shown to provide a remarkably good and useful representation of hysteresis in superconductors. The solutions of the differential equation provide expressions for important hysteresis curves. From analysis based on the ideas of the Bean and Kim models, in which the critical current density is related to the width of the major loop, expressions for the major loop are used to establish a system of nonlinear equations for the critical current density, the equilibrium magnetization, and their derivatives. This system of equations can be used to evaluate free parameters in assumed forms for the critical current density. Here, the equations are used to compute values for J(c) and M(e) directly. Sample calculations with analytic forms of f,g, and alpha, and data from measured hysteresis curves are presented. RP HODGDON, ML (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 14 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 FEB 15 PY 1991 VL 69 IS 4 BP 2388 EP 2396 DI 10.1063/1.348725 PG 9 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400085 ER PT J AU HUBBARD, KM BORDES, N NASTASI, M TESMER, JR AF HUBBARD, KM BORDES, N NASTASI, M TESMER, JR TI SUPERCONDUCTING YBACUO THIN-FILMS BY CU-ION IMPLANTATION SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB We have investigated the fabrication of thin-film superconductors by Cu-ion implantation into initially Cu-deficient Y(BaF2)Cu thin films. The precursor films were co-evaporated on SrTiO3 substrates, and subsequently implanted to various doses with 400 keV Cu-63(2+). Implantations were performed at both LN2 temperature, and at 380-degrees-C. The films were post-annealed in oxygen, and characterized as a function of dose by four-point probe analysis, x-ray diffraction; ion-beam backscattering and channeling, and scanning electron microscopy. It was found that a significant improvement in film quality could be achieved by heating the films to 380-degrees-C during the implantation. The best films made became fully superconducting at 60-70 K, and exhibited good metallic R vs T behavior in the normal state. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP HUBBARD, KM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 19 TC 0 Z9 0 U1 0 U2 3 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 FEB 15 PY 1991 VL 69 IS 4 BP 2397 EP 2404 DI 10.1063/1.348692 PG 8 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400086 ER PT J AU MONTEIRO, OR EVANS, JW JOHNSON, SM AF MONTEIRO, OR EVANS, JW JOHNSON, SM TI INSITU OBSERVATION OF THE ORTHORHOMBIC-TETRAGONAL PHASE-TRANSFORMATION IN YBA2CU3O7-DELTA SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BA-CU-O; DIFFRACTION; SYSTEM AB We have carried out in situ heat treatments of YBa2Cu3O7-delta at temperatures between 25 and 500-degrees-C and oxygen pressure of 10 Torr. It was found that the original orthorhombic (OI phase) YBa2Cu3O7-delta transforms into the OII phase (still orthorhombic, but with a doubling of the a-axis, and with a delta = 0.5) at about 250-degrees-C. As the temperature is increased further, the tetragonal phase of YBa2Cu3O7-delta forms. As the tetragonal phase is slowly cooled to room temperature, the orthorhombic phase OI reappears. Cycling the temperature repeatedly has indicated the regenerability of the OI phase. C1 SRI INT,MENLO PK,CA 94025. RP MONTEIRO, OR (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 20 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1991 VL 69 IS 4 BP 2414 EP 2417 DI 10.1063/1.348674 PG 4 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400089 ER PT J AU WILLIAMS, RK BRYNESTAD, J HENSON, TJ KROEGER, DM MARSH, GC PADGETT, RA SCARBROUGH, JO AF WILLIAMS, RK BRYNESTAD, J HENSON, TJ KROEGER, DM MARSH, GC PADGETT, RA SCARBROUGH, JO TI PREPARATION AND GRAIN-BOUNDARY CHEMISTRY OF DENSE POLYCRYSTALLINE YBA2CU4O-APPROXIMATELY 8 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CU-O; SUPERCONDUCTING PROPERTIES; OXYGEN-PRESSURE; YBA2CU4O8; PHASE; YBA2CU3O7-X; FILMS AB Dense polycrystalline samples of the compound YBa2Cu4O approximately 8, Y124, were prepared by a three-step procedure. In the first step a mixture of Y2O3, CuO and BaO2 was reacted at 960-degrees-C under an oxygen pressure of 55 bar. The compound did not sinter under these conditions but electrical resistivity and susceptibility measurements showed that the oxide mixture converted to Y124. In the second step densification was produced by hot isostatic pressing at 875-degrees-C. This degraded the superconducting properties severely and a final high-temperature anneal in pressurized oxygen was required to restore optimum properties. This anneal consisted of a one hour hold at 1010-degrees-C in 40-bar O2 followed by a 24-h anneal at 950-degrees-C in 55-bar O2. After this treatment the samples were approximately 90% dense, phase pure Y124. The maximum grain dimensions were about 10-mu-m, and Auger spectroscopy data were obtained on a fracture surface. These data showed that the grain boundary composition does not differ significantly from the bulk values. C1 OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP WILLIAMS, RK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 27 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1991 VL 69 IS 4 BP 2426 EP 2430 DI 10.1063/1.348677 PG 5 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400092 ER PT J AU EXARHOS, GJ SCHAAF, JW AF EXARHOS, GJ SCHAAF, JW TI RAMAN-SCATTERING FROM BORON-NITRIDE COATINGS AT HIGH-TEMPERATURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DEPENDENCE AB The temperature dependence from ambient to 2325 K of the high frequency E2g mode intrinsic to the hexagonal phase of boron nitride has been determined using a pulsed-excitation gated-detection technique which effectively discriminates against sample blackbody emission. A monotonic decrease of 80 cm-1 in mode frequency accompanied by a marked increase in linewidth was observed over this temperature range. Simultaneous acquisition of both Stokes and anti-Stokes Raman scattering has been demonstrated and provides another method by which sample temperatures may be verified. Variations in measured linewidth and mode frequency are described in terms of an anharmonic oscillator model from which the intralamellar thermal expansion coefficient is estimated. C1 LOWER COLUMBIA COLL, LONGVIEW, WA 98632 USA. RP EXARHOS, GJ (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 22 TC 26 Z9 26 U1 0 U2 7 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 FEB 15 PY 1991 VL 69 IS 4 BP 2543 EP 2548 DI 10.1063/1.348695 PG 6 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400110 ER PT J AU LEMKE, RW BACON, LD AF LEMKE, RW BACON, LD TI THEORY AND SIMULATION OF A HIGH-POWER MICROWAVE CONVERTER FOR CURRENT-DENSITY-MODULATED, ANNULAR, RELATIVISTIC ELECTRON-BEAMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The efficiency of converting the kinetic energy of a current-density-modulated, annular, relativistic electron beam into high-power microwaves depends on details of the beam, and the convertor geometry. The latter issue is investigated in this paper for a particular choice of convertor. Maxwell's equations are solved for the case in which a structure comprised of a cylindrical cavity coupled to a waveguide by an impedance transformer is excited by a symmetric, transverse magnetic wave. The field solutions are employed to determine the effect that the transformer/waveguide system has on the resonant properties of the cavity. An example is given in which the analytic model is used to obtain maximum power output in a numerical simulation. RP LEMKE, RW (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1991 VL 69 IS 4 BP 2639 EP 2643 DI 10.1063/1.348657 PG 5 WC Physics, Applied SC Physics GA EZ664 UT WOS:A1991EZ66400127 ER PT J AU MEHLHORN, RJ AF MEHLHORN, RJ TI ASCORBATEASCORBIC AND DEHYDROASCORBIC ACID-MEDIATED REDUCTION OF FREE-RADICALS IN THE HUMAN ERYTHROCYTE SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID SPIN PROBES; VITAMIN-E; LIPID-PEROXIDATION; ALPHA-TOCOPHEROL; ASCORBIC-ACID; EPIDERMIS; RESONANCE; MITOCHONDRIA; ANTIOXIDANT; INDIVIDUALS AB Nitroxides were used as models of persistent free radicals to study the antioxidant function of ascorbic acid in the human erythrocyte. It was concluded that: 1) ascorbate and other reductant(s) derived from dehydroascorbic acid (DHA) in the presence of thiols are the only significant reducing agents for nitroxides, 2) glutathione and DHA reduce nitroxides by a process that cannot be inhibited by ascorbic acid oxidase, 3) erythrocytes can be depleted of ascorbic acid by exhaustive washing in the presence of membrane-permeable cationic nitroxides such as N,N-dimethylamino-Tempo, 4) ascorbate-depleted cells do not reduce nitroxides; however, nitroxide reduction is restored when the cells are incubated with DHA, 5) reduction of nitroxides in ascorbate-depleted, DHA-treated cells is significantly faster than in buffered solutions of DHA and glutathione, 6) several equivalents of nitroxide are reduced relative to the intracellular ascorbate pool, 7) sustained nitroxide reduction is observed even when most of the intracellular ascorbate is oxidized, 8) spin trapping of oxyradicals in tert-butyl hydroperoxide-treated cells is accelerated with ascorbate depletion and inhibited with ascorbate loading, 9) ascorbate can be quantified within intact cells by analyzing the initial reduction rates of membrane-permeable cationic nitroxides, and 10) DHA-stimulated reduction of cationic nitroxides is slower and less extensive in erythrocytes deficient in glucose-6-phosphate dehydrogenase than in normal erythrocytes. C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720. RP MEHLHORN, RJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,MAILSTOP 70-193A,BERKELEY,CA 94720, USA. FU NIA NIH HHS [AG 04818] NR 40 TC 76 Z9 76 U1 0 U2 1 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 FEB 15 PY 1991 VL 266 IS 5 BP 2724 EP 2731 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EX600 UT WOS:A1991EX60000011 PM 1993652 ER PT J AU ZAJFMAN, D BELKACEM, A GRABER, T KANTER, EP MITCHELL, RE NAAMAN, R VAGER, Z ZABRANSKY, BJ AF ZAJFMAN, D BELKACEM, A GRABER, T KANTER, EP MITCHELL, RE NAAMAN, R VAGER, Z ZABRANSKY, BJ TI MEASUREMENT OF THE DISTRIBUTION OF BOND ANGLES IN H2O+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOELECTRON-SPECTRA; MOLECULES AB A quantitative analysis of the bending mode of H2O+ is made using the Coulomb Explosion technique. The full extent of the angular distribution is measured and is in good agreement with the previously measured bending frequency. The equilibrium value for the angle is extracted from the data with high precision and is in excellent agreement with theoretical predictions as well as spectroscopic measurements. C1 UNIV ILLINOIS, DEPT PHYS, CHICAGO, IL 60680 USA. WEIZMANN INST SCI, DEPT CHEM PHYS, IL-76100 REHOVOT, ISRAEL. WEIZMANN INST SCI, DEPT NUCL PHYS, IL-76100 REHOVOT, ISRAEL. RP ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439 USA. NR 22 TC 17 Z9 17 U1 2 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1991 VL 94 IS 4 BP 2543 EP 2547 DI 10.1063/1.459881 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000021 ER PT J AU KULANDER, KC CERJAN, C OREL, AE AF KULANDER, KC CERJAN, C OREL, AE TI TIME-DEPENDENT CALCULATIONS OF MOLECULAR PHOTODISSOCIATION RESONANCES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SYMMETRIC TRIATOMIC-MOLECULES; REACTIVE SCATTERING; PHOTO-DISSOCIATION; PHOTODETACHMENT SPECTRUM; SPECTROSCOPY; DYNAMICS AB The molecular photodissociation dynamics of a model, collinear CO2 system is investigated using the time-dependent wave packet method. Resonance structures in the absorption line shape, found previously in time-independent studies, are correlated to particular oscillatory motions in the dissociating wave packet dynamics. Dramatic changes in the absorption line shape are predicted for this system for short pulse excitation due to the removal of the effects of one class of resonances. Three different methods of solving the time-dependent Schrodinger equation were tested and the optimal scheme was used in these calculations. C1 UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616. RP KULANDER, KC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV V,LIVERMORE,CA 94550, USA. NR 21 TC 34 Z9 34 U1 0 U2 2 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 FEB 15 PY 1991 VL 94 IS 4 BP 2571 EP 2577 DI 10.1063/1.459833 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000025 ER PT J AU DUCHOVIC, RJ WAGNER, AF TURNER, RE GARNER, DM FLEMING, DG AF DUCHOVIC, RJ WAGNER, AF TURNER, RE GARNER, DM FLEMING, DG TI THE ANALYSIS OF MUONIUM HYPERFINE INTERACTION MEASUREMENTS OF THERMAL RATE CONSTANTS FOR ADDITION-REACTIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CHARGE-EXCHANGE COLLISIONS; LOW-PRESSURE GASES; COMPETING PROCESSES; TEMPERATURE-RANGE; KINETIC-EQUATIONS; SPIN-EXCHANGE; MOLECULAR ION; DEPENDENCE; HYDROGEN; RADICALS AB A new model is developed for the analysis of muon spin relaxation (mu-SR) measurements of muonium (Mu) reaction rates with other chemical species. The kinetics component of the model is specifically developed for addition reactions but can be extended to direct reactions. The polarization component of the model assumes that the adduct formed possesses a single, effective spin precession frequency. The complete model is solved to obtain an analytic expression for the mu-SR signal as a function of time. Both a time-ordered sequence method and a Boltzmann spin equation method give equivalent solutions. These solutions are analyzed under various kinetic conditions. It is concluded that the coefficient controlling the decay of the mu-SR signal is closely related to the adduct formation rate constant, i.e., the high pressure limit of the apparent bimolecular addition rate constant. In the most favorable case, the decay constant gives the adduct formation rate constant directly at all pressures of buffer gas. C1 TRIUMF,VANCOUVER V6T 2A3,BC,CANADA. UNIV BRITISH COLUMBIA,DEPT CHEM,VANCOUVER V6T 1W5,BC,CANADA. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 48 TC 24 Z9 24 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 FEB 15 PY 1991 VL 94 IS 4 BP 2794 EP 2806 DI 10.1063/1.459856 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000050 ER PT J AU GRAY, SK WOZNY, CE AF GRAY, SK WOZNY, CE TI FRAGMENTATION MECHANISMS FROM 3-DIMENSIONAL WAVE PACKET STUDIES - VIBRATIONAL PREDISSOCIATION OF NECL2, HECL2, NEICL, AND HEICL SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; MOLECULAR-DYNAMICS; PHASE-SPACE; VANDERWAALS COMPLEXES; STATE; PHOTODISSOCIATION; DISTRIBUTIONS; DISSOCIATION; SCATTERING AB We present three-dimensional, time-dependent quantum studies on the van der Waals vibrational predissociation reactions of NeCl2, HeCl2, NeICl, and HeICl. A wave packet/basis set expansion approach is employed. The results for these systems agree reasonably well with experiment and time-independent quantum calculations, where available. The similarities and differences among the four systems are explored by detailed inspection of the propagating wave function. The rotational product distributions can be understood in terms of a unified fragmentation mechanism that depends on the product of the initial probability density with a classical force, and short time dynamics. Quantum interference effects are shown to play an important role in the helium cases. A semiclassical model is also advanced to account for some features of the product distributions. C1 NO ILLINOIS UNIV,DEPT CHEM,DE KALB,IL 60115. RP GRAY, SK (reprint author), ARGONNE NATL LAB,DIV CHEM,THEORET CHEM GRP,ARGONNE,IL 60439, USA. NR 48 TC 99 Z9 99 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 FEB 15 PY 1991 VL 94 IS 4 BP 2817 EP 2832 DI 10.1063/1.459858 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000052 ER PT J AU PFUND, DM LEE, LL COCHRAN, HD AF PFUND, DM LEE, LL COCHRAN, HD TI CHEMICAL-POTENTIALS FROM INTEGRAL-EQUATIONS USING SCALED PARTICLE THEORY .1. THEORY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FLUID MIXTURES; COMPUTER-SIMULATION; CRITICAL-POINT; FREE-ENERGY; CONSISTENT; BEHAVIOR AB A new method is presented for calculating chemical potentials using integral equation theories. The method uses a multistep charging process which allows attractive and repulsive contributions to the chemical potential to be determined separately. The hybrid mean spherical approximation is used to provide needed correlations about the test particle. A novel application of particle scaling is used to determine the repulsive, or cavity formation contribution to the chemical potential. A formal definition is given for the effective hard core diameter of a softly repulsive solute molecule. A simple Kirkwood charging process is used to determine the attractive, or solvent-solute binding contribution to the chemical potential. The use of an integral equation theory for estimating the test particle correlation functions allows chemical potentials and solvent-solute bindings to be determined in nonideal mixtures at supercritical conditions. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RP PFUND, DM (reprint author), UNIV OKLAHOMA,SCH CHEM ENGN & MAT SCI,NORMAN,OK 73019, USA. NR 31 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1991 VL 94 IS 4 BP 3107 EP 3113 DI 10.1063/1.459781 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000082 ER PT J AU PFUND, DM LEE, LL COCHRAN, HD AF PFUND, DM LEE, LL COCHRAN, HD TI CHEMICAL-POTENTIALS FROM INTEGRAL-EQUATIONS USING SCALED PARTICLE THEORY .2. TESTING AND APPLICATIONS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FLUID MIXTURES; COMPUTER-SIMULATION; SIMPLE LIQUIDS; FREE-ENERGY; CONSISTENT AB Presented are the results of testing the method for estimating chemical potentials which was described in paper I. The method, which is based on scaled particle theory, provides accurate chemical potentials in mixtures of softly repulsive particles when used with the Rogers-Young integral equation. Calculated excess Gibbs energies agreed with simulations to an average of -0.67% for 2:1 diameter ratio mixtures. The method provides approximate results in Lennard-Jones mixtures when used with the hybrid mean spherical approximation integral equation theory. Results for supercritical isotherms reproduce simulation data to an average of -3.0%. For subcritical isotherms, vapor results are exact while liquid results are qualitatively correct. The method used with the integral equation theory correctly predicts the effect of energy ratio on the Henry's Law constant. The predicted effect of size ratio on the constant has an incorrect slope at subcritical temperatures when the solvent density is near the value for a saturated liquid. The incorrect slope results from inaccuracies in the predicted correlation functions for the fluid surrounding the test particle. The method allows estimates to be made of the work of cavity formation and of the strength of solvent-solute binding in near-critical mixtures. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RP PFUND, DM (reprint author), UNIV OKLAHOMA,SCH CHEM ENGN & MAT SCI,NORMAN,OK 73019, USA. NR 25 TC 17 Z9 17 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 FEB 15 PY 1991 VL 94 IS 4 BP 3114 EP 3131 DI 10.1063/1.459782 PG 18 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY070 UT WOS:A1991EY07000083 ER PT J AU SUGAMA, T KUKACKA, LE CARCIELLO, N WARREN, JB AF SUGAMA, T KUKACKA, LE CARCIELLO, N WARREN, JB TI INFLUENCE OF THE HIGH-TEMPERATURE TREATMENT OF ZINC PHOSPHATE CONVERSION COATINGS ON THE CORROSION PROTECTION OF STEEL SO JOURNAL OF MATERIALS SCIENCE LA English DT Article AB An anhydrous alpha-Zn3(PO-4)2 phase converted by the dehydration of hydrous zinc phosphate, Zn3(PO4)2.2H2O, crystal coatings in air at a temperature of approximately 300-degrees-C, significantly enhances the corrosion resistance of steel, and also reduces the susceptibility of the crystals to alkaline dissolution. A subsequent alpha-->gamma phase transition at approximately 500-degrees-C results in a poor protection behaviour, because of the formation of numerous microcracks on the crystal faces. RP SUGAMA, T (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV PROC SCI,UPTON,NY 11973, USA. NR 8 TC 4 Z9 4 U1 1 U2 2 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD FEB 15 PY 1991 VL 26 IS 4 BP 1045 EP 1050 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA EY759 UT WOS:A1991EY75900026 ER PT J AU ASSINK, RA ARNOLD, C HOLLANDSWORTH, RP AF ASSINK, RA ARNOLD, C HOLLANDSWORTH, RP TI PREPARATION OF OXIDATIVELY STABLE CATION-EXCHANGE MEMBRANES BY THE ELIMINATION OF TERTIARY HYDROGENS SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE MEMBRANE PREPARATION AND STRUCTURE; ION-EXCHANGE MEMBRANES; COMPOSITE MEMBRANE; BATTERIES; MEMBRANE STABILITY AB Model compounds and radiatively grafted membranes were prepared in order to study the effect of tertiary hydrogens on the stability of membranes used in oxidatively aggressive environments. Sulfonated isopropylbenzene, which contains a tertiary hydrogen, yielded substantial amounts of degradation products when exposed to a strong oxidizing solution. Sulfonated t-butylbenzene, which is identical to sulfonated isopropylbenzene except that the tertiary hydrogen is replaced by a methyl group, yielded only minute amounts of degradation products when exposed to the same oxidizing solution. Styrene (contains a tertiary hydrogen) and alpha-methylstyrene (tertiary hydrogen has been replaced by a methyl group) were radiatively grafted onto poly (tetrafluoroethylene) films and sulfonated to form cationic membranes. The styrene-prepared membrane exhibited several times more weight loss during exposure to an oxidizing aging solution than did the alpha-methylstyrene prepared membrane. The energy efficiencies of styrene-grafted membranes decreased rapidly to less than 60% after 60 or 80 cycles in a cycling test cell. The energy efficiencies of alpha-methylstyrene grafted membranes were 82.6% and 83.0% for 700 test cycles and showed no effects of chemical degradation during this period. C1 LOCKHEED MISSILES & SPACE CO,PALO ALTO,CA 94304. RP ASSINK, RA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 8 TC 59 Z9 59 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD FEB 15 PY 1991 VL 56 IS 2 BP 143 EP 151 DI 10.1016/S0376-7388(00)80804-2 PG 9 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA FB866 UT WOS:A1991FB86600002 ER PT J AU BRAMMER, L HOWARD, JAK JOHNSON, O KOETZLE, TF SPENCER, JL STRINGER, AM AF BRAMMER, L HOWARD, JAK JOHNSON, O KOETZLE, TF SPENCER, JL STRINGER, AM TI LOW-TEMPERATURE NEUTRON-DIFFRACTION STUDY OF BIS(TRI-PARA-TOLYLPHOSPHINE)HEPTAHYDRIDORHENIUM(VII), [REH7(P(C6H4CH3-4)3)2] - A POLYHYDRIDE COMPLEX WITH A SHORT H=H CONTACT THAT MODELS AN INTERMEDIATE STAGE IN THE OXIDATIVE ADDITION OF DIHYDROGEN AT TRANSITION-METAL CENTERS SO JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS LA English DT Article ID SINGLE-CRYSTAL; MOLECULAR-STRUCTURE; X-RAY; RHENIUM; BOND AB Low-temperature neutron diffraction shows that the title compound has an H ... H separation [1.357(7) angstrom] intermediate in length between the accepted ranges for 'classical' non-bonded dihydrides and more recently reported dihydrogen ligands, thus providing a model for the intermediate stages of oxidative addition of dihydrogen at transition metal centres. C1 UNIV BRISTOL,DEPT INORGAN CHEM,BRISTOL BS8 1TS,AVON,ENGLAND. UNIV SALFORD,DEPT CHEM & APPL CHEM,SALFORD M5 4WT,LANCS,ENGLAND. RP BRAMMER, L (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Howard, Judith /H-7113-2012 NR 25 TC 81 Z9 81 U1 2 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0022-4936 J9 J CHEM SOC CHEM COMM JI J. Chem. Soc.-Chem. Commun. PD FEB 15 PY 1991 IS 4 BP 241 EP 243 DI 10.1039/c39910000241 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA FA238 UT WOS:A1991FA23800022 ER PT J AU BARTOSZEK, L BHARADWAJ, V CHURCH, MD HAHN, AA PEOPLES, J PORDES, SH RAPIDIS, PA WERKEMA, SJ AGAHI, D BROEMMELSIEK, DR FAST, JE GEE, M GOLLWITZER, KE MANDELKERN, MA MARQUES, JL SCHULTZ, J WEBER, MF GINSBURG, CM MASUZAWA, M RAY, RE ROSEN, JL TROKENHEIM, S ZHAO, JL ARMSTRONG, TA HUFFORD, GE LEWIS, RA MAJEWSKA, AM REID, JD SMITH, GA HASAN, MA BIINO, C PALESTINI, S AF BARTOSZEK, L BHARADWAJ, V CHURCH, MD HAHN, AA PEOPLES, J PORDES, SH RAPIDIS, PA WERKEMA, SJ AGAHI, D BROEMMELSIEK, DR FAST, JE GEE, M GOLLWITZER, KE MANDELKERN, MA MARQUES, JL SCHULTZ, J WEBER, MF GINSBURG, CM MASUZAWA, M RAY, RE ROSEN, JL TROKENHEIM, S ZHAO, JL ARMSTRONG, TA HUFFORD, GE LEWIS, RA MAJEWSKA, AM REID, JD SMITH, GA HASAN, MA BIINO, C PALESTINI, S TI THE E760 LEAD-GLASS CENTRAL CALORIMETER - DESIGN AND INITIAL TEST-RESULTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ALUMINIZED MYLAR TUBES; RADIATIVE DECAYS; CHARGE DIVISION; J-PSI; CHAMBER; ANNIHILATIONS; SPECTROMETER; PERFORMANCE; DETECTOR; PHYSICS AB The central calorimeter in Fermilab experiment E760++ has been designed to measure the topology and energies of electrons and photons in the decay of charmonium formed in ppBAR annihilation. The calorimeter is composed of 1280 lead-glass Cherenkov counters read out with photomultiplier tubes. This paper discusses design criteria for the calorimeter and describes how these criteria were met. Data from tests in low energy (10-84 MeV) and medium energy (1-4 GeV) beams are presented showing a spatial resolution of 9 mm, an energy resolution of (3.0 +/- 0.3)%/square-root E[GeV] + (1.5 +/- 0.5)%, and an effective energy threshold below 10 MeV. C1 UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. NORTHWESTERN UNIV,DEPT PHYS,EVANSTON,IL 60201. PENN STATE UNIV,DEPT PHYS,ELEMENTARY PARTICLE SCI LAB,UNIVERSITY PK,PA 16802. PENN STATE UNIV,DEPT PHYS,YORK,PA 17403. IST NAZL FIS NUCL,I-10125 TURIN,ITALY. RP BARTOSZEK, L (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 34 TC 40 Z9 40 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 15 PY 1991 VL 301 IS 1 BP 47 EP 60 DI 10.1016/0168-9002(91)90737-B PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FB253 UT WOS:A1991FB25300007 ER PT J AU GEER, S HOLROYD, RA PTOHOS, F AF GEER, S HOLROYD, RA PTOHOS, F TI SEARCH FOR NEW ROOM-TEMPERATURE LIQUIDS FOR USE IN IONIZATION CHAMBERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ELECTRON-MOBILITY; TETRAMETHYLSILANE; 2,2,4-TRIMETHYLPENTANE; PERFORMANCE; CALORIMETER; RANGES; FIELD AB Ionization currents and free ion yields have been measured as a function of applied electric field for ten room temperature liquids containing silicon, germanium, or tin atoms. The highest free ion yields measured are for those liquids having small spherical molecules; tetramethylsilane, tetramethylgermanium, and tetramethyltin. We have updated our earlier measurements for tetramethyltin with a much reduced systematic uncertainty obtained by calculating the contribution to the ionization current from the photoelectric absorption of low energy photons. Tetramethylgermanium and tetramethyltin both have free ion yields similar to tetramethylsilane, making them interesting candidates for use in ionization chambers. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. RP GEER, S (reprint author), HARVARD UNIV,HIGH ENERGY PHYS LAB,42 OXFORD ST,CAMBRIDGE,MA 02138, USA. NR 21 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 15 PY 1991 VL 301 IS 1 BP 61 EP 68 DI 10.1016/0168-9002(91)90738-C PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FB253 UT WOS:A1991FB25300008 ER PT J AU ANDERSEN, E BARNES, PD CASTANO, B CHERNEY, M COHLER, M DELACRUZ, B DIEBOLD, GE DULNY, B FERNANDEZ, C FRANKLIN, G FRUHWIRTH, R GARABATOS, C GARZON, JA GEIST, WM GOMEZ, A GREINER, D GRUHN, C HAFIDOUNI, M HRUBEC, J JONES, PG JUDD, E KUIPERS, JPM DEGUEVARA, PL LADREM, M LIKO, D LOPEZPONTE, S LOVHOIDEN, G MACNAUGHTON, J MICHALON, A MICHALONMENTZER, ME MOSQUERA, J NATKANIEC, Z NELSON, JM NEUHOFER, G DELOSHEROS, CP PLO, M PORTH, P POWELL, B QUINN, B RAMIL, A REGLER, M ROHRINGER, H SAKREJDA, I SCHUMACHER, R STAMPFER, D THORSTEINSEN, T TRAXLER, J YANEZ, A YEPES, P ZYBERT, R AF ANDERSEN, E BARNES, PD CASTANO, B CHERNEY, M COHLER, M DELACRUZ, B DIEBOLD, GE DULNY, B FERNANDEZ, C FRANKLIN, G FRUHWIRTH, R GARABATOS, C GARZON, JA GEIST, WM GOMEZ, A GREINER, D GRUHN, C HAFIDOUNI, M HRUBEC, J JONES, PG JUDD, E KUIPERS, JPM DEGUEVARA, PL LADREM, M LIKO, D LOPEZPONTE, S LOVHOIDEN, G MACNAUGHTON, J MICHALON, A MICHALONMENTZER, ME MOSQUERA, J NATKANIEC, Z NELSON, JM NEUHOFER, G DELOSHEROS, CP PLO, M PORTH, P POWELL, B QUINN, B RAMIL, A REGLER, M ROHRINGER, H SAKREJDA, I SCHUMACHER, R STAMPFER, D THORSTEINSEN, T TRAXLER, J YANEZ, A YEPES, P ZYBERT, R TI DETERMINATION OF THE PRIMARY VERTEX POSITION IN THE NA36 EXPERIMENT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB A new method is described for finding the primary vertex in a relativistic heavy-ion experiment with multiple nuclear targets. Due to the large number of tracks the use of an economic algorithm is essential. The method comes from system theory and is based on an application of the Kalman filter. The small uncertainty in the vertex position obtained provides a reliable target assignment for the interaction. C1 CIEMAT,DIV FIS PARTICULAS,E-28040 MADRID,SPAIN. UNIV SANTIAGO,DEPT FIS PARTICULAS,E-15706 SANTIAGO,SPAIN. INST HOCHENERGIEPHYS,A-1050 VIENNA,AUSTRIA. UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. UNIV LOUIS PASTEUR,CNRS,INST NATL PHYS NUCL & PHYS PARTICULES,CTR RECH NUCL,F-67037 STRASBOURG,FRANCE. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV BIRMINGHAM,DEPT PHYS,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. CERN,CH-1211 GENEVA 23,SWITZERLAND. INST NUCL PHYS,PL-30055 KRAKOW 30,POLAND. CREIGHTON UNIV,DEPT PHYS,OMAHA,NE 68178. CARNEGIE MELLON UNIV,DEPT PHYS,PITTSBURGH,PA 15213. RP ANDERSEN, E (reprint author), UNIV BERGEN,DEPT PHYS,N-5007 BERGEN,NORWAY. RI Fruhwirth, Rudolf/H-2529-2012; Gomez Tato, Andres/D-6396-2011; Schumacher, Reinhard/K-6455-2013; de la Cruz, Begona/K-7552-2014; Yanez, Armando/L-2957-2014; Plo Casasus, Maximo/M-1445-2014; Ramil, Alberto/B-4698-2008; OI Schumacher, Reinhard/0000-0002-3860-1827; Yanez, Armando/0000-0003-4626-7993; Plo Casasus, Maximo/0000-0002-2289-918X; Ramil, Alberto/0000-0002-5333-9425; Quinn, Brian/0000-0003-2800-986X; Franklin, Gregg/0000-0003-4176-1378; Perez de los Heros, Carlos/0000-0002-2084-5866 NR 11 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 FEB 15 PY 1991 VL 301 IS 1 BP 69 EP 75 DI 10.1016/0168-9002(91)90739-D PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FB253 UT WOS:A1991FB25300009 ER PT J AU SHAPIRA, D TEH, K BLANKENSHIP, J BURKS, B FOUTCH, L KIM, HJ KOROLIJA, M MCCONNELL, JW MESSICK, M NOVOTNY, R RENTSCH, D SHEA, J WIELECZKO, JP AF SHAPIRA, D TEH, K BLANKENSHIP, J BURKS, B FOUTCH, L KIM, HJ KOROLIJA, M MCCONNELL, JW MESSICK, M NOVOTNY, R RENTSCH, D SHEA, J WIELECZKO, JP TI THE HILI - A MULTIDETECTOR SYSTEM FOR LIGHT-IONS AND HEAVY-IONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ARRAY AB A detector system with a large acceptance, high granularity and a logarithmic response, has been built. It is well suited to detect simultaneously, heavy and light fragments from nucleus-nucleus collisions at energies higher than 10 MeV/nucleon. The angular range spanned by this detector system is +/- 20-degrees in-plane and +/- 16-degrees out-of-plane with the exclusion of a 2.5-degrees cone around the beam axis. Coverage with a large dynamic range is provided with four large gas filled ionization chambers and behind them a 192-element hodoscope made of individual fast + slow plastic scintillation telescopes in a "phoswich" arrangement. C1 VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. RUDJER BOSKOVIC INST,YU-41001 ZAGREB,YUGOSLAVIA. JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. CENS,SERV PHYS NUCL BASSE ENERGIE,F-91191 GIF SUR YVETTE,FRANCE. UNIV GIESSEN,INST PHYS 2,W-6300 GIESSEN,GERMANY. TEXAS A&I UNIV,KINGSVILLE,TX 78363. GETTYSBURG COLL,GETTYSBURG,PA 17325. RP SHAPIRA, D (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 15 TC 19 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 15 PY 1991 VL 301 IS 1 BP 76 EP 95 DI 10.1016/0168-9002(91)90740-H PG 20 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FB253 UT WOS:A1991FB25300010 ER PT J AU ROMERO, LA DICKEY, FM AF ROMERO, LA DICKEY, FM TI COMPARISON BETWEEN THE PEAK-TO-SIDELOBE RATIO OF THE MATCHED AND PHASE-ONLY FILTERS SO OPTICS LETTERS LA English DT Article AB It is shown that for any given bandpass, the phase-only filter always gives a better peak-to-correlation energy than the matched filter. An example is given that shows that this result does not carry over when one uses a more general measure of the peak-to-sidelobe ratio. RP ROMERO, LA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 5 TC 2 Z9 2 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 15 PY 1991 VL 16 IS 4 BP 253 EP 254 DI 10.1364/OL.16.000253 PG 2 WC Optics SC Optics GA EW374 UT WOS:A1991EW37400021 PM 19773899 ER PT J AU SMITH, AV RAYMOND, TD AF SMITH, AV RAYMOND, TD TI AUTOIONIZING DECAY-RATES MEASURED BY OPTICAL NUTATION SO OPTICS LETTERS LA English DT Article AB Using a single-mode pulsed laser we have measured autoionizing lifetimes for the 3p'3D states of atomic oxygen by measuring the dependence of ionization on the fluence of light driving the 3s' 3D-3p' 3D transition. From the frequency of the Rabi oscillations we deduce transition strengths, and from the modulation depth we calculate ionization lifetimes. These are to our knowledge the first measurements of these quantities for these transitions. RP SMITH, AV (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 6 TC 2 Z9 2 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 15 PY 1991 VL 16 IS 4 BP 267 EP 269 DI 10.1364/OL.16.000267 PG 3 WC Optics SC Optics GA EW374 UT WOS:A1991EW37400026 PM 19773904 ER PT J AU KREKELS, T VANTENDELOO, G BRODDIN, D AMELINCKX, S TANNER, L MEHBOD, M VANLATHEM, E DELTOUR, R AF KREKELS, T VANTENDELOO, G BRODDIN, D AMELINCKX, S TANNER, L MEHBOD, M VANLATHEM, E DELTOUR, R TI TWEED STRUCTURE OF FE-DOPED YBA2CU3O7-DELTA SO PHYSICA C LA English DT Article ID ELECTRON-DIFFRACTION; CRYSTAL-GROWTH; SUPERCONDUCTIVITY; MICROSTRUCTURES; YBA2CU3O7-DELTA; ORIGIN AB Fe-doped YBa2Cu3O7-delta single crystals have been prepared by a flux method from an Y-Ba-Cu-O precursor with copper partially substituted by iron. Electron diffraction and microscopy were applied to study the domain structure of the material. Superposed on a broad twin band texture, as also observed in undoped material, all samples reveal a finer "tweed" structure of overlapping lenticular domains oriented along [120] and [11BAR0]. This suggests a two-step formation process of the domain structure. The displacement field, corresponding with the tweed structure, resembles that of microtwinning in undoped, quenched YBa2Cu3O7-delta samples. The randomly dispersed Fe-ions act as pinning centers or fragment the structure by the induction of twin interfaces. Monte Carlo simulations support this idea. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV LIBRE BRUXELLES,B-1050 BRUSSELS,BELGIUM. RP KREKELS, T (reprint author), ANTWERP STATE UNIV CTR,171 GROENENBORGERLAAN,B-2020 ANTWERP,BELGIUM. NR 25 TC 62 Z9 62 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 15 PY 1991 VL 173 IS 5-6 BP 361 EP 376 DI 10.1016/0921-4534(91)90737-J PG 16 WC Physics, Applied SC Physics GA EZ609 UT WOS:A1991EZ60900008 ER PT J AU GAO, Y BAI, G LAM, DJ MERKLE, KL AF GAO, Y BAI, G LAM, DJ MERKLE, KL TI MICROSTRUCTURE AND DEFECTS IN ALPHA-AXIS ORIENTED YBA2CU3O7-X THIN-FILMS SO PHYSICA C LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; SUPERCONDUCTING PROPERTIES; SUBSTRATE; PRESSURE; SRTIO3 AB MOCVD-grown, a-axis oriented YBa2Cu3O7-x thin films have been studied by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). The majority of the thin film material is oriented with the a-axis perpendicular to the substrate surface, while about 20% of the material has the c-axis perpendicular to the substrate. The c-axis oriented grains are disconnected from each other, and are separated by a-axis oriented grains. There are two types of a-axis oriented grains, differing by a 90-degrees rotation of the c-axis. HREM images in conjunction with image simulation analysis are used to derive the atomic structures of the 90-degrees rotation grain boundaries and of defect structures in the film. The majority of the grain boundaries is asymmetrical, bounded by (010) (001) lattice planes. However extended steps, whose segments are mostly parallel to the (013) (013) planes, are also present, thus forming short facets of symmetric grain boundaries. The latter are believed to be important in forming weak-link-free connections between the grains. The misfit at (010) (001) grain boundaries is accommodated by the formation of stacking faults, which were identified to be 124-type defects. The grain boundary structures are discussed in terms of correlations with the electric transport properties across the boundaries. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCTIV,ARGONNE,IL 60439. RP GAO, Y (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 30 TC 40 Z9 41 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 FEB 15 PY 1991 VL 173 IS 5-6 BP 487 EP 500 DI 10.1016/0921-4534(91)90751-J PG 14 WC Physics, Applied SC Physics GA EZ609 UT WOS:A1991EZ60900022 ER PT J AU WILCOXON, JP AF WILCOXON, JP TI CRITICAL-BEHAVIOR OF AN INVERSE MICELLE SYSTEM SO PHYSICAL REVIEW A LA English DT Article ID CONCENTRATION FLUCTUATIONS; EXPONENTS; DYNAMICS; POINT AB We report measurements of the critical behavior of an inverted micelle system. The two-component system consists of a noionic surfactant n-decyl octaoxyethylene glycol monoether (C10E8) in a hydrocarbon, dodecane. The system has an upper critical consolute point at 30 +/- 2 wt.% C10E8 at a temperature of T = 28.05 +/- 0.03-degrees-C. We demonstrate that both static and dynamic scaling are obeyed with universal three-dimensional Ising exponents describing the divergence of the osmotic compressibility and the static correlation length. RP WILCOXON, JP (reprint author), SANDIA NATL LABS,ORG 1153,ALBUQUERQUE,NM 87108, USA. NR 13 TC 13 Z9 13 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 15 PY 1991 VL 43 IS 4 BP 1857 EP 1860 DI 10.1103/PhysRevA.43.1857 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX997 UT WOS:A1991EX99700019 ER PT J AU MONGE, A COHEN, EGD ERPENBECK, JJ AF MONGE, A COHEN, EGD ERPENBECK, JJ TI EQUIPARTITION OF ENERGY IN A ONE-DIMENSIONAL MODEL OF DIATOMIC-MOLECULES .2. MAXIMAL LYAPUNOV EXPONENT AND PHASE-SPACE TRAJECTORY SEPARATION SO PHYSICAL REVIEW A LA English DT Article ID SPECTRA; EQUILIBRIUM; FLUIDS AB The Lyapunov instability is studied numerically for a one-dimensional model of diatomic molecules with harmonic intramolecular and hard intermolecular interactions. Previous results are extended to characterize the equipartition regime in terms of the two parameters of the system, the number of molecules n and the vibrational frequency omega. When the system is in equipartition, we find the existence of a thermodynamic limit for the maximal Lyapunov exponent and a power-law behavior omega-alpha, in analogy with the Fermi-Pasta-Ulam model. The separation of trajectories in phase space, investigated by considering the time dependence of the distance of initially close trajectories and by averaging over the phase space, is related to the maximal Lyapunov exponent and shown to be an alternative way to compute it when n is not too large. Multiple-precision arithmetic analysis for the model and its link to Lyapunov instability are also discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP MONGE, A (reprint author), ROCKEFELLER UNIV,NEW YORK,NY 10021, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 15 PY 1991 VL 43 IS 4 BP 2031 EP 2040 DI 10.1103/PhysRevA.43.2031 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX997 UT WOS:A1991EX99700036 ER PT J AU KLEMS, JH AF KLEMS, JH TI X-RAY ABSORPTION IN VALENCE-EXCITED MOLECULES AS A POSSIBLE CONTRAST MECHANISM FOR CHEMICALLY SENSITIVE IMAGING AND SPECTROSCOPY SO PHYSICAL REVIEW A LA English DT Article ID K-BETA-EMISSION; SYNCHROTRON RADIATION; SPECTRA; MICROPROBE; SULFUR AB A pump-probe technique, x-ray inverse fluorescence allowed by molecular excitation (XIFAME), is proposed as a contrast mechanism for x-ray microscopy. The technique consists of using a laser to produce holes in the valence levels of selected molecules; these holes then permit inverse fluorescent absorption transitions to occur. The method would permit the selective mapping of simple molecular structures and oxidation states of light elements. Cross-section estimates are made, and it is argued that the technique is potentially more sensitive than imaging techniques based on the atomic absorption edge. It is also argued that XIFAME has advantages over the use of x-ray-absorption near-edge structure for spectroscopic measurements of very dilute molecular structures. RP KLEMS, JH (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720, USA. NR 25 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 15 PY 1991 VL 43 IS 4 BP 2041 EP 2045 DI 10.1103/PhysRevA.43.2041 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX997 UT WOS:A1991EX99700037 ER PT J AU EVANS, JW AF EVANS, JW TI FACTORS MEDIATING SMOOTHNESS IN EPITAXIAL THIN-FILM GROWTH SO PHYSICAL REVIEW B LA English DT Article ID ENERGY ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; SOLVABLE IRREVERSIBLE-PROCESSES; INTENSITY OSCILLATIONS; BALLISTIC DEPOSITION; SURFACE-DIFFUSION; MODELS; ADSORPTION; STATISTICS; MECHANISM AB Surface-sensitive diffraction techniques are often used to monitor the smoothness of epitaxial thin films during growth, i.e., the propensity for layer-by-layer growth. Interpretation of such data requires an understanding of the relative importance of various factors that mediate smoothness. These include the adsorption-site geometry, the dynamics of atoms during deposition, and possible transient mobility following deposition, as well as thermal diffusion. Here we present a systematic study of the first three factors, emphasizing the interplay between geometry and dynamics. This is achieved by a comparison of several "low-temperature" far-from-equilibrium growth models where adsorption occurs at on-top sites, bridge sites, or threefold or fourfold hollow sites. Film structure is elucidated through determination of the interface width, density of steps and adsorption sites, the kinematic Bragg intensity, and short-range-order parameters. Exact analysis of nonasymptotic properties of these statistical-mechanical models is in general impossible, and so most results presented are from Monte Carlo simulation. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT MATH,AMES,IA 50011. RP EVANS, JW (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011, USA. NR 47 TC 102 Z9 102 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 5 BP 3897 EP 3905 DI 10.1103/PhysRevB.43.3897 PG 9 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100011 ER PT J AU MAHAN, GD AF MAHAN, GD TI THE BENEDICKS EFFECT - NONLOCAL ELECTRON-TRANSPORT IN METALS SO PHYSICAL REVIEW B LA English DT Article ID ALKALI-METALS; THERMOPOWER AB The Benedicks effect is the voltage difference between two points in a solid that are at the same temperature. A nonzero value may be obtained if the temperature profile between the points is asymmetric. We derive the nonlocal transport theory of a metal from the Boltzmann equation, and use the results to discuss the Benedicks effect. The nonlocal theory is needed whenever the electron mean free path has the same size as variations in the gradients of the voltage, temperature, or chemical potential. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP MAHAN, GD (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 19 TC 6 Z9 6 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 5 BP 3945 EP 3951 DI 10.1103/PhysRevB.43.3945 PG 7 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100017 ER PT J AU ZHENG, XY RITCHIE, RH AF ZHENG, XY RITCHIE, RH TI IMAGE POTENTIAL FOR AN ELECTRON NEAR AN IMPENETRABLE SURFACE SO PHYSICAL REVIEW B LA English DT Article ID METAL-SURFACES; DYNAMICAL CORRECTIONS; SELF-ENERGY; STATES; MODEL; DISTRIBUTIONS; RESONANCES; REFLECTION; CHARGES AB A self-energy formalism is used to determine the quantal image potential for an electron near an impenetrable solid surface. The electron is considered to be in a Coulombic potential outside a repulsive wall. The complete, orthonormal basis set of wave functions for an electron in such a model potential is employed in the calculation of the image potential. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. RP ZHENG, XY (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,POB 2008,OAK RIDGE,TN 37831, USA. NR 31 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 FEB 15 PY 1991 VL 43 IS 5 BP 4002 EP 4006 DI 10.1103/PhysRevB.43.4002 PG 5 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100024 ER PT J AU CRANDALL, RS AF CRANDALL, RS TI DEFECT RELAXATION IN AMORPHOUS-SILICON - STRETCHED EXPONENTIALS, THE MEYER-NELDEL RULE, AND THE STAEBLER-WRONSKI EFFECT SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; INDUCED CONDUCTIVITY CHANGES; INDUCED METASTABLE DEFECTS; SOLAR-CELL DEGRADATION; THIN-FILM TRANSISTORS; ANNEALING BEHAVIOR; LIGHT; HYDROGEN; EQUILIBRIUM; TEMPERATURE AB Annealing and production of metastable defects in disordered solids is explained quantitatively with a model in which defect relaxation is a local phenomenon. The stretched-exponential time dependence of defect relaxation and the Meyer-Neldel rule for the relaxation-time constant are natural consequences of this model. The results are obtained by using an exponential distribution of activation barriers for transitions between the two states of the local defect. The model, applied to data in hydrogenated amorphous silicon, a-Si:H, gives an exponential distribution of barriers with a characteristic temperature of 220-degrees-C, roughly equal to the accepted freeze-in temperature for defect distributions in a-Si:H. The model explains that long degradation times convert defects with higher barriers and this results in longer annealing times. The microscopic models of the metastable defects in a-Si:H, weak-bond breaking and carrier trapping by charged dangling bonds, are discussed in the framework of this defect-relaxation model. RP CRANDALL, RS (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. NR 65 TC 180 Z9 181 U1 3 U2 27 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 FEB 15 PY 1991 VL 43 IS 5 BP 4057 EP 4070 DI 10.1103/PhysRevB.43.4057 PG 14 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100033 ER PT J AU KIM, DS YU, PY AF KIM, DS YU, PY TI HOT-ELECTRON RELAXATIONS AND HOT PHONONS IN GAAS STUDIED BY SUBPICOSECOND RAMAN-SCATTERING SO PHYSICAL REVIEW B LA English DT Article ID GROUP-VELOCITY DISPERSION; SELF-PHASE MODULATION; INTERVALLEY SCATTERING; POLAR SEMICONDUCTORS; LIGHT-SCATTERING; QUANTUM WELLS; HOLE PLASMA; DYNAMICS; SPECTROSCOPY; EXCITATION AB We have utilized subpicosecond laser pulses to excite and probe hot electrons and nonequilibrium longitudinal-optical (LO) phonons in bulk GaAs by Raman scattering. We find that the photoexcited hot electrons cool at a rate much faster than predicted by intravalley scattering of LO phonons via the Frolich interaction. On the other hand, this fast cooling rate can be accounted for satisfactorily by intervalley scattering. As a result of this very rapid cooling, the temperature of the hot LO phonons generated by the hot electrons temporarily overshoots the electron temperature. From the electron cooling curve and the dependence of the hot-phonon temperature on the excited-electron density, we determined the deformation potential for scattering between the GAMMA and L conduction-band valleys in GaAs. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP KIM, DS (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 39 TC 66 Z9 67 U1 0 U2 5 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 FEB 15 PY 1991 VL 43 IS 5 BP 4158 EP 4169 DI 10.1103/PhysRevB.43.4158 PG 12 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100043 ER PT J AU KOILLER, B OSORIO, R FALICOV, LM AF KOILLER, B OSORIO, R FALICOV, LM TI GAP PROPERTIES OF ALNGA8-NAS8 ORDERED COMPOUNDS SO PHYSICAL REVIEW B LA English DT Article ID ALXGA1-XAS BAND-EDGE; ELECTRONIC-STRUCTURE; SEMICONDUCTOR ALLOYS; OPTICAL-PROPERTIES; TIGHT-BINDING; DEPENDENCE AB The small-crystal approach with a 16-site basic cluster is used to determine the electronic structure of 16 inequivalent ordered structures of Al(n)Ga(8-n)As8 compounds. The energy gaps and oscillator strengths for the main gap transitions are calculated, and different results are obtained for different structures of the same composition n, which illustrates the role of compositional ordering in the electronic properties of alloys. Average values of these quantities are used as an attempt to describe Al(x)Ga(1-x)As alloys. Important features of our results are (a) a positive curvature in the averaged gap versus x dependence for small x and (b) a smooth featureless decrease of the averaged oscillator strength with x. This last feature implies that the direct-indirect gap crossover in the alloy system cannot be genuinely obtained by any sort of averaging among Al(n)Ga(8-n)As8 ordered compounds. C1 UNIV BRASILIA,DEPT FIS,BR-70910 BRASILIA,DF,BRAZIL. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP KOILLER, B (reprint author), PONTIFICIA UNIV CATOLICA RIO DE JANEIRO,DEPT FIS,CAIXA POSTALE 38071,BR-22452 RIO DE JANEIRO,RJ,BRAZIL. NR 26 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 FEB 15 PY 1991 VL 43 IS 5 BP 4170 EP 4173 DI 10.1103/PhysRevB.43.4170 PG 4 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100044 ER PT J AU SURH, MP LI, MF LOUIE, SG AF SURH, MP LI, MF LOUIE, SG TI SPIN-ORBIT-SPLITTING OF GAAS AND INSB BANDS NEAR GAMMA SO PHYSICAL REVIEW B LA English DT Article ID ZINCBLENDE-TYPE SEMICONDUCTORS; CONDUCTION-BAND; INSULATORS AB An ab initio pseudopotential calculation is used to examine the spin-orbit splitting of states in the zinc-blende semiconductors GaAs and InSb within the local-density approximation (LDA). The relativistic pseudopotentials are generated with the occupied d orbitals of the atoms in the rigid core. No correction is made to the calculated band gaps even though they are too small as a result of the LDA, resulting in a semimetal for InSb. These two features differ from an earlier ab initio linear muffin-tin orbitals (LMTO) calculation in which mixing of the d core states was included and the gap was corrected empirically. We examine the spin-orbit splitting of the valence bands at point GAMMA, and the linear-in-[kappa] splitting and mixing of the upper valence bands for the [100], [111], and [110] directions in a small region around point GAMMA. This provides a detailed calculation of the splitting and mixing of the light- and heavy-hole valence bands in the region of near-degeneracy. We also examine the linear and cubic terms away from point GAMMA in the [110] direction where the light and heavy holes are separated in energy and do not intermix appreciably. The spin-orbit splittings and linear-in-kappa valence-band splittings are in excellent agreement with the LMTO calculation and with experiment; however, an error in earlier analyses regarding the relative sign of two linear terms is found. The cubic terms are, for the most part, not accurate, which is expected from a local-density-functional calculation. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP SURH, MP (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 25 TC 25 Z9 25 U1 1 U2 9 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 FEB 15 PY 1991 VL 43 IS 5 BP 4286 EP 4294 DI 10.1103/PhysRevB.43.4286 PG 9 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100058 ER PT J AU ZAK, J AF ZAK, J TI COMMENT ON THE EXISTENCE PROOFS OF THE WANNIER-STARK LADDER SO PHYSICAL REVIEW B LA English DT Letter ID CONSTANT ELECTRIC-FIELD; BLOCH ELECTRON AB In a series of three recent papers by Emin and Hart, it is claimed that the existence of Wannier-Stark ladders can be proved by splitting the electric-field potential into sawlike and steplike portions. It is shown in this Comment that the proofs in these three papers are incorrect. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP ZAK, J (reprint author), TECHNION ISRAEL INST TECHNOL,DEPT PHYS,HAIFA,ISRAEL. NR 8 TC 29 Z9 29 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 5 BP 4519 EP 4520 DI 10.1103/PhysRevB.43.4519 PG 2 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100089 ER PT J AU HART, CF EMIN, D AF HART, CF EMIN, D TI COMMENT ON THE EXISTENCE PROOFS OF THE WANNIER-STARK LADDER - REPLY SO PHYSICAL REVIEW B LA English DT Letter AB An additional proof of the relationship that Zak questions is presented. A physical interpretation of this relationship is given. The distinction between a Bloch electron and a free electron are stressed. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP HART, CF (reprint author), SO ILLINOIS UNIV,DEPT PHYS,CARBONDALE,IL 62901, USA. NR 5 TC 6 Z9 6 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 5 BP 4521 EP 4522 DI 10.1103/PhysRevB.43.4521 PG 2 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100090 ER PT J AU SMITH, HG BERLINER, R JORGENSEN, JD TRIVISONNO, J AF SMITH, HG BERLINER, R JORGENSEN, JD TRIVISONNO, J TI PRESSURE EFFECTS ON THE MARTENSITIC-TRANSFORMATION IN METALLIC SODIUM SO PHYSICAL REVIEW B LA English DT Note ID PHASE-TRANSITIONS; LITHIUM; LI; NA AB Na has been shown to undergo a partial martensitic transformation from the bcc lattice to a combination of the 9R lattice and a trigonal or hexagonal lattice below 35 K, somewhat similar to that of lithium, which transforms to a 9R lattice plus an fcc lattice. Recent neutron-scattering experiments on Li under hydrostatic pressure showed a pronounced increase in the transition temperature from 75 to about 90 K at a pressure of 6.5 kbar. Similar experiments on Na, however, show a decrease in the transition temperature with pressure, actually suppressing the 9R transition at 1 kbar to 15 K. C1 UNIV MISSOURI,MISSOURI RES REACTOR FACIL,COLUMBIA,MO 65211. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. JOHN CARROLL UNIV,DEPT PHYS,CLEVELAND,OH 44118. RP SMITH, HG (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 8 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 5 BP 4524 EP 4526 DI 10.1103/PhysRevB.43.4524 PG 3 WC Physics, Condensed Matter SC Physics GA EX921 UT WOS:A1991EX92100092 ER PT J AU ERIKSSON, O HAO, YG COOPER, BR FERNANDO, GW COX, LE WARD, JW BORING, AM AF ERIKSSON, O HAO, YG COOPER, BR FERNANDO, GW COX, LE WARD, JW BORING, AM TI ELECTRONIC-STRUCTURE OF HYDROGEN AND OXYGEN CHEMISORBED ON PLUTONIUM - THEORETICAL-STUDIES SO PHYSICAL REVIEW B LA English DT Article ID SURFACES; HYDRIDES; ENERGIES; SYSTEM AB The film linearized-muffin-tin-orbital method has been used to calculate the electronic structure of hydrogen and oxygen chemisorbed on plutonium. The calculated work functions are larger than that obtained for a clean Pu surface. This suggests that a change in the surface dipole moment is induced by the chemisorbed H and O atoms. For the H chemisorbed state it is found that the fourfold-bridging position is stable with regard to motion out of or into the plutonium surface plane-with only a small relaxation effect, and that the energy gained when the H atoms chemisorb on the Pu surface is 4.0 eV per atom. The localized, spin-polarized 5f electrons in PuH2 are found to induce a substantial conduction-band moment. The calculations suggest that the electronic structure of the oxygen chemisorbed state is more covalent than the hydrogen chemisorbed state. C1 W VIRGINIA UNIV,DEPT PHYS,MORGANTOWN,WV 26506. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP ERIKSSON, O (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 24 TC 26 Z9 26 U1 1 U2 5 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 FEB 15 PY 1991 VL 43 IS 6 BP 4590 EP 4597 DI 10.1103/PhysRevB.43.4590 PG 8 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300004 ER PT J AU GOUDONNET, JP BIJEON, JL WARMACK, RJ FERRELL, TL AF GOUDONNET, JP BIJEON, JL WARMACK, RJ FERRELL, TL TI SUBSTRATE EFFECTS ON THE SURFACE-ENHANCED RAMAN-SPECTRUM OF BENZOIC-ACID ADSORBED ON SILVER OBLATE MICROPARTICLES SO PHYSICAL REVIEW B LA English DT Article ID SCATTERING; PARTICLES; ROUGHNESS; FILMS AB The effects of the local dielectric environment on the surface-enhanced Raman-scattering enhancement factor of benzoic acid adsorbed on silver oblate spheroids are studied experimentally and modeled theoretically. Silver-island films were annealed to produce spheroidal-shaped particles which exhibit well resolved resonances in absorption spectra. These resonances are shifted in different amounts by the depolarizing interaction with the substrate. An additional dielectric film has been deposited between the particles and substrate in order to measure the effects of proximity on the surface-enhanced Raman signal. Experimental observations on germanium and silicon are presented and found to be in agreement with calculations involving only the surface-plasmon excitation on the particles. RP GOUDONNET, JP (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831, USA. RI Bijeon, Jean-Louis/C-3972-2012; OI Warmack, Robert/0000-0001-8298-2420 NR 18 TC 15 Z9 15 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 FEB 15 PY 1991 VL 43 IS 6 BP 4605 EP 4612 DI 10.1103/PhysRevB.43.4605 PG 8 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300006 ER PT J AU MEI, J DAVENPORT, JW FERNANDO, GW AF MEI, J DAVENPORT, JW FERNANDO, GW TI ANALYTIC EMBEDDED-ATOM POTENTIALS FOR FCC METALS - APPLICATION TO LIQUID AND SOLID COPPER SO PHYSICAL REVIEW B LA English DT Article ID INTERATOMIC INTERACTIONS; MOLECULAR-DYNAMICS; TRANSITION-METALS; METHOD MODEL; BCC METALS; DERIVATION; AU AB A simple analytic embedded-atom model that includes more than nearest neighbors is presented. Parameters for Cu, Ag, Au, Ni, Pd, and Pt have been obtained. The model has been applied to study the thermodynamic properties of copper with molecular dynamics. The calculated fractional density change on melting, heat of fusion, linear coefficients of thermal expansion, and heat capacities above room temperature are in good agreement with experimental results. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP MEI, J (reprint author), SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794, USA. NR 30 TC 166 Z9 177 U1 3 U2 16 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 FEB 15 PY 1991 VL 43 IS 6 BP 4653 EP 4658 DI 10.1103/PhysRevB.43.4653 PG 6 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300012 ER PT J AU SANDY, AR MOCHRIE, SGJ ZEHNER, DM HUANG, KG GIBBS, D AF SANDY, AR MOCHRIE, SGJ ZEHNER, DM HUANG, KG GIBBS, D TI STRUCTURE AND PHASES OF THE AU(111) SURFACE - X-RAY-SCATTERING MEASUREMENTS SO PHYSICAL REVIEW B LA English DT Article ID COMMENSURATE-INCOMMENSURATE TRANSITION; SCANNING TUNNELING MICROSCOPY; RECONSTRUCTED SURFACE; RESOLUTION FUNCTION; GOLD CRYSTALLITES; STRESS TENSOR; DOMAIN-WALLS; GRAPHITE; DISLOCATIONS; ENERGY AB The results of a comprehensive synchrotron x-ray-scattering study of the clean, reconstructed Au(111) surface between 300 and 1250 K are presented. Two surface phases are identified and characterized. For T < 865 K, the reconstruction consists of a series of discommensurations, separating surface regions with the correct face-centered-cubic (fcc) ABC stacking sequence from regions with a faulted AB A stacking sequence. A key feature of this phase is the existence of an equilibrium density of kinks between rotationally equivalent domains. At 865 K, the reconstruction starts to lose long-range order. The first-order transformation to a disordered phase is complete by 880 K. In this phase, the topmost layer has hexagonal symmetry and is on the average isotropically compressed compared with bulk (111) planes. Between 880 and 1250 K the translational correlation length and the average compression of the overlayer evolve only slightly. Interpretation of the x-ray reflectivity, both specular and nonspecular, establishes, however, that the occupation of fcc C sites and faulted A sites is approximately constant throughout the temperature range studied. In addition, the separation between the top two layers is expanded 3% relative to the bulk (111) interlayer spacing and the surface-normal vibrational amplitude in the surface layers is enhanced with respect to the bulk value. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP SANDY, AR (reprint author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA. NR 62 TC 212 Z9 212 U1 1 U2 31 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 FEB 15 PY 1991 VL 43 IS 6 BP 4667 EP 4687 DI 10.1103/PhysRevB.43.4667 PG 21 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300014 ER PT J AU TOMANEK, D SUN, Z LOUIE, SG AF TOMANEK, D SUN, Z LOUIE, SG TI ABINITIO CALCULATION OF CHEMISORPTION SYSTEMS - H ON PD(001) AND PD(110) SO PHYSICAL REVIEW B LA English DT Article ID THERMAL-DESORPTION SPECTROSCOPY; COLD NUCLEAR-FUSION; HYDROGEN CHEMISORPTION; STRUCTURAL-PROPERTIES; ELECTRONIC-STRUCTURE; SUBSURFACE HYDROGEN; DEUTERIUM ATOMS; ADSORPTION SITE; PD(100) SURFACE; W 001 AB We present an ab initio density-functional calculation of the interaction of hydrogen with the Pd(001) and Pd(110) surfaces and with bulk palladium. Our results for the H-Pd system are complemented by calculations for the H-2 molecule, the bulk, and the clean (001) and (110) surfaces of Pd. In the case of H in bulk Pd, we determine the equilibrium geometry and electronic structure and discuss the nature of the Pd-H bond. For the adsorption system H/Pd(001) and H/Pd(110), we determine the preferential adsorption sites, bond lengths, and vibration frequencies of the adsorbate. We relate H-induced softening of Pd-surface-phonon frequencies to a corresponding softening of Pd-Pd interactions in the bulk hydride phase. C1 MICHIGAN STATE UNIV,CTR FUNDAMENTAL MAT RES,E LANSING,MI 48824. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP TOMANEK, D (reprint author), MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824, USA. RI Tomanek, David/B-3275-2009 OI Tomanek, David/0000-0003-1131-4788 NR 71 TC 74 Z9 74 U1 0 U2 5 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 FEB 15 PY 1991 VL 43 IS 6 BP 4699 EP 4713 DI 10.1103/PhysRevB.43.4699 PG 15 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300016 ER PT J AU FUCHS, HD GREIN, CH THOMSEN, C CARDONA, M HANSEN, WL HALLER, EE ITOH, K AF FUCHS, HD GREIN, CH THOMSEN, C CARDONA, M HANSEN, WL HALLER, EE ITOH, K TI COMPARISON OF THE PHONON-SPECTRA OF GE-70 AND NATURAL GE CRYSTALS - EFFECTS OF ISOTOPIC DISORDER SO PHYSICAL REVIEW B LA English DT Article ID BOND CHARGE MODEL; TEMPERATURE-DEPENDENCE; STABLE ISOTOPES; SCATTERING; DIAMOND; DYNAMICS; SI; SN AB The difference in phonon energies and broadenings between an isotopically enriched crystal of Ge-70 (95.9%) and a germanium crystal of natural isotopic composition was measured with high accuracy in first- and second-order Raman spectra (with laser excitation energies of E(L) = 2.41 eV and E(L) = 2.183 eV, respectively) and compared to coherent-potential-approximation and lowest-order perturbation-theory calculations. The energy of the first-order O (GAMMA) phonon shifts up by 4.9 +/- 0.1 cm-1 in the isotopically pure crystal, in good agreement with the calculated value of 4.3 +/- 0.4 cm-1. No broadening due to isotopic disorder was observed for optical phonons at the GAMMA-point [full width at half maximum (FWHM) of 0.99 +/- 0.03 cm-1 at 80 K for both crystals]. However, additional broadening at the W and L point was found in the second-order Raman spectra (FWHM broadening of 6.5 +/- 0.5 cm-1 at the L point). This broadening and the shifts of the acoustic- and optical-phonon peaks in the second-order spectra agree well with calculations of the phonon overtone density of states. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP FUCHS, HD (reprint author), MAX PLANCK INST FESTKORPERFORSCH,HEISENBERGSTR 1,W-7000 STUTTGART 80,GERMANY. RI Thomsen, Christian/E-2295-2012; Thomsen, Christian/B-5014-2015; Itoh, Kohei/C-5738-2014 OI Thomsen, Christian/0000-0001-6057-1401; NR 37 TC 74 Z9 74 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 6 BP 4835 EP 4842 DI 10.1103/PhysRevB.43.4835 PG 8 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300032 ER PT J AU NELSON, JS WRIGHT, AF FONG, CY AF NELSON, JS WRIGHT, AF FONG, CY TI 1ST-PRINCIPLES VIRTUAL-CRYSTAL CALCULATIONS OF ALXGA1-XAS DISORDERED ALLOYS AND HETEROSTRUCTURES - BAND OFFSETS AND ABSOLUTE ALLOY ENERGIES SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; SEMICONDUCTOR ALLOYS; PSEUDOPOTENTIAL CALCULATIONS; DEFORMATION POTENTIALS; PHASE-DIAGRAMS; SUPERLATTICES; STATES; GAAS; INSTABILITY; DEPENDENCE AB The results of first-principles virtual-crystal calculations of the band structures of Al(x)Ga(1-x)As disordered alloys and the valence- and conduction-band offsets of Al(x)Ga(1-x)As/GaAs (001) heterostructures are presented. We find that the variations of the band-edge states (GAMMA-15v, GAMMA-1c, X1c, and L1c) with alloying predicted by the virtual-crystal calculations are in good agreement with experiments and exhibit only a very small amount of optical bowing. We also find that, to a good approximation, both the valence- and conduction-band offsets vary linearly with composition. C1 SANDIA NATL LABS,DIV THEORET PHYS 8341,LIVERMORE,CA 94550. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. RP NELSON, JS (reprint author), SANDIA NATL LABS,DIV SEMICOND PHYS 1143,ALBUQUERQUE,NM 87185, USA. NR 39 TC 26 Z9 27 U1 2 U2 5 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 FEB 15 PY 1991 VL 43 IS 6 BP 4908 EP 4914 DI 10.1103/PhysRevB.43.4908 PG 7 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300042 ER PT J AU XU, CH WANG, CZ CHAN, CT HO, KM AF XU, CH WANG, CZ CHAN, CT HO, KM TI THEORY OF THE THERMAL-EXPANSION OF SI AND DIAMOND SO PHYSICAL REVIEW B LA English DT Article ID LATTICE-DYNAMICAL PROPERTIES; STRUCTURAL-PROPERTIES; SILICON; SOLIDS; SEMICONDUCTORS; GE AB Phonon-dispersion curves, lattice mode Gruneisen parameters, and the coefficients of thermal expansion are calculated for Si and C within a tight-binding model. The results are in good agreement with experimental data. The origin of the negative thermal expansion in Si is examined, and we find that the different thermal-expansion behaviors between Si and C can be explained by the different relative strengths of bond-bending and bond-stretching forces. C1 IOWA STATE UNIV SCI & TECHNOL,MICROELECTR RES CTR,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP XU, CH (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 26 TC 109 Z9 111 U1 5 U2 21 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 FEB 15 PY 1991 VL 43 IS 6 BP 5024 EP 5027 DI 10.1103/PhysRevB.43.5024 PG 4 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300056 ER PT J AU EMIN, D HART, CF AF EMIN, D HART, CF TI EXISTENCE OF WANNIER-STARK LOCALIZATION - REPLY SO PHYSICAL REVIEW B LA English DT Letter AB We present another proof of the relationship that Leo and MacKinnon dispute. C1 SO ILLINOIS UNIV,DEPT PHYS,CARBONDALE,IL 62901. RP EMIN, D (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 2 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1991 VL 43 IS 6 BP 5169 EP 5169 DI 10.1103/PhysRevB.43.5169 PG 1 WC Physics, Condensed Matter SC Physics GA EY623 UT WOS:A1991EY62300079 ER PT J AU BARROW, JD COPELAND, EJ KOLB, EW LIDDLE, AR AF BARROW, JD COPELAND, EJ KOLB, EW LIDDLE, AR TI BARYOGENESIS IN EXTENDED INFLATION .1. BARYOGENESIS VIA PRODUCTION AND DECAY OF SUPERMASSIVE BOSONS SO PHYSICAL REVIEW D LA English DT Article ID EARLY UNIVERSE; GRAVITY; STRINGS AB We consider baryogenesis occurring during the thermalization stage at the end of extended inflation. In extended inflation, the Universe passes through a first-order phase transition via bubble nucleation; inflation comes to an end when bubbles collide and their collisions convert energy stored in the bubble walls into particles. This naturally provides conditions well out of thermal equilibrium in which baryon-number-violating processes may proceed; we estimate the amount of baryon asymmetry which may be produced this way. The avoidance of a monopole or domain-wall problem can also be ensured and isothermal density perturbations may arise as a remnant of spatial variation in the baryon asymmetry. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP BARROW, JD (reprint author), UNIV SUSSEX,DIV PHYS & ASTRON,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. NR 34 TC 21 Z9 21 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 977 EP 983 DI 10.1103/PhysRevD.43.977 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400003 ER PT J AU BARROW, JD COPELAND, EJ KOLB, EW LIDDLE, AR AF BARROW, JD COPELAND, EJ KOLB, EW LIDDLE, AR TI BARYOGENESIS IN EXTENDED INFLATION .2. BARYOGENESIS VIA PRIMORDIAL BLACK-HOLES SO PHYSICAL REVIEW D LA English DT Article ID 1ST-ORDER PHASE-TRANSITION; PARTICLE EMISSION RATES; EARLY UNIVERSE AB This is the second of two papers devoted to the study of baryogenesis at the end of extended inflation. Extended inflation is brought to an end by the collisions of bubble walls surrounding regions of true vacuum, a process which produces particles well out of thermal equilibrium. In the first paper we considered baryogenesis via direct production and subsequent decay of baryon-number-violating bosons. In this paper we consider the further possibility that the wall collisions may provide a significant density of primordial black holes and examine their possible role in generating a baryon asymmetry. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP BARROW, JD (reprint author), UNIV SUSSEX,DIV PHYS & ASTRON,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. NR 33 TC 56 Z9 56 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 984 EP 994 DI 10.1103/PhysRevD.43.984 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400004 ER PT J AU HOLMAN, R KOLB, EW VADAS, SL WANG, Y AF HOLMAN, R KOLB, EW VADAS, SL WANG, Y TI EXTENDED INFLATION FROM HIGHER-DIMENSIONAL THEORIES SO PHYSICAL REVIEW D LA English DT Article ID FALSE VACUUM; UNIVERSE; COMPACTIFICATION; COSMOLOGY; REDUCTION; FLATNESS; DYNAMICS; HORIZON; FATE AB We consider the possibility that higher-dimensional theories may, upon reduction to four dimensions, allow extended inflation to occur. We analyze two separate models. One is a very simple toy model consisting of higher-dimensional gravity coupled to a scalar field whose potential allows for a first-order phase transition. The other is a more sophisticated model incorporating the effects of nontrivial field configurations (monopole, Casimir, and fermion bilinear condensate effects) that yield a nontrivial potential for the radius of the internal space. We find that extended inflation does not occur in these models. We also find that the bubble nucleation rate in these theories is time dependent unlike the case in the original version of extended inflation. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. RP HOLMAN, R (reprint author), CARNEGIE MELLON UNIV,DEPT PHYS,PITTSBURGH,PA 15213, USA. RI Wang, Yun/B-5724-2011 OI Wang, Yun/0000-0002-4749-2984 NR 31 TC 61 Z9 61 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 995 EP 1004 DI 10.1103/PhysRevD.43.995 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400005 ER PT J AU SALOPEK, DS BOND, JR AF SALOPEK, DS BOND, JR TI STOCHASTIC INFLATION AND NONLINEAR GRAVITY SO PHYSICAL REVIEW D LA English DT Article ID DENSITY PERTURBATIONS; DARK MATTER; UNIVERSE; DYNAMICS AB We show how nonlinear effects of the metric and scalar fields may be included in stochastic inflation. Our formalism can be applied to non-Gaussian fluctuation models for galaxy formation. Fluctuations with wavelengths larger than the horizon length are governed by a network of Langevin equations for the physical fields. Stochastic noise terms arise from quantum fluctuations that are assumed to become classical at horizon crossing and that then contribute to the background. Using Hamilton-Jacobi methods, we solve the Arnowitt-Deser-Misner constraint equations which allows us to separate the growing modes from the decaying ones in the drift phase following each stochastic impulse. We argue that the most reasonable choice of time hypersurfaces for the Langevin system during inflation is T = ln(Ha), where H and a are the local values of the Hubble parameter and the scale factor, since T is the natural time for evolving the short-wavelength scalar field fluctuations in an inhomogenous background. We derive a Fokker-Planck equation which describes how the probability distribution of scalar field values at a given spatial point evolves in T. Analytic Green's-function solutions obtained for a single scalar field self-interacting through an exponential potential are used to demonstrate (1) if the initial condition of the Hubble parameter is chosen to be consistent with microwave-background limits, H(phi-0)/m-rho less-than-or-similar-to 10(-4), then the fluctuations obey Gaussian statistics to a high precision, independent of the time hypersurface choice and operator-ordering ambiguities in the Fokker-Planck equation, and (2) for scales much larger than our present observable patch of the Universe, the distribution is non-Gaussian, with a tail extending to large energy densities; although there are no observable manifestations, it does show eternal inflation. Lattice simulations of our Langevin network for the exponential potential demonstrate how spatial correlations are incorporated. An initially homogeneous and isotropic lattice develops fluctuations as more and more quantum fluctuation modes leave the horizon, yielding Gaussian contour maps for a region corresponding to our observable patch and non-Gaussian contour maps for the ultra-large-scale structure of the Universe. Inflation models with extended non-Gaussian tails at observable scales would lead to a radically different cosmic structure than Gaussian perturbations give. C1 UNIV TORONTO,CANADIAN INST THEORET ASTROPHYS,CANADIAN INST ADV RES PROGRAM,TORONTO M5S 1A1,ONTARIO,CANADA. RP SALOPEK, DS (reprint author), NASA,FERMILAB ASTROPHYS CTR,POB 500 MS-209,BATAVIA,IL 60510, USA. NR 41 TC 155 Z9 155 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1005 EP 1031 DI 10.1103/PhysRevD.43.1005 PG 27 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400006 ER PT J AU MEYER, BS ALCOCK, CR MATHEWS, GJ FULLER, GM AF MEYER, BS ALCOCK, CR MATHEWS, GJ FULLER, GM TI SPECTRUM OF QCD NUCLEATION-SITE SEPARATIONS AND PRIMORDIAL NUCLEOSYNTHESIS SO PHYSICAL REVIEW D LA English DT Article ID HADRON PHASE-TRANSITION; NEUTRON DIFFUSION; EARLY UNIVERSE; INHOMOGENEITY AB The spectrum of nucleation-site separations in the cosmic QCD phase transition is calculated within the framework of homogeneous nucleation theory. This spectrum has the property that the ratio of the standard deviation of the separations to the mean separation has the constant value of 0.466, independent of any QCD physics parameters. When the assumption is made that a duality exists between nucleation sites and baryon fluctuation sites, the same spectrum may be applied to baryon-number fluctuation separations. When nucleosynthesis results are averaged over this spectrum, the upper limit on OMEGA-b(2.735K/T0)3 x (H0/50 kms-1Mpc-1)2, as derived from the observed upper limit to the primordial He-4 abundance, drops from 0.8 to 0.56 in baryon inhomogeneous universes. In order for macroscopic baryon inhomogeneities to arise in the early Universe, persist to the era of nucleosynthesis, and give nucleosynthesis yields which allow OMEGA-b to be greater than the limit from standard big-bang nucleosynthesis, the QCD surface tension must be near its upper limit of around the cube of the coexistence temperature. C1 UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. RP MEYER, BS (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550, USA. NR 26 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1079 EP 1086 DI 10.1103/PhysRevD.43.1079 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400015 ER PT J AU KURKISUONIO, H CENTRELLA, J AF KURKISUONIO, H CENTRELLA, J TI PRIMORDIAL NUCLEOSYNTHESIS WITH HORIZON-SCALE CURVATURE FLUCTUATIONS SO PHYSICAL REVIEW D LA English DT Article ID HADRON PHASE-TRANSITION; THERMONUCLEAR REACTION-RATES; PLANAR NUMERICAL COSMOLOGY; BIG-BANG NUCLEOSYNTHESIS; NEUTRON DIFFUSION; COSMIC NUCLEOSYNTHESIS; EARLY UNIVERSE; INHOMOGENEITY; NUMBER; EQUATIONS AB We have used a plane-symmetric numerical relativity and hydrodynamics code to study the effect of horizon-scale inhomogeneities in the energy density and spacetime curvature on primordial nucleosynthesis. H-2, He-3, and Li-7 yields are chiefly determined by the local baryon-to-photon ratios during nucleosynthesis, whereas He-4 depends on previous dynamical history which determines how many neutrons survive until nucleosynthesis. Strong (delta-rho/rho approximately 1) inhomogeneities are allowed by the observed abundances. Inhomogeneities usually raise both He-4 and H-2 but in some cases a nonadiabatic curvature inhomogeneity leads to a He-4 yield below the standard-model result with the same average baryon-to-photon ratio. C1 DREXEL UNIV,DEPT PHYS & ATMOSPHER SCI,PHILADELPHIA,PA 19104. RP KURKISUONIO, H (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Kurki-Suonio, Hannu/B-8502-2016 OI Kurki-Suonio, Hannu/0000-0002-4618-3063 NR 42 TC 3 Z9 3 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1087 EP 1105 DI 10.1103/PhysRevD.43.1087 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400016 ER PT J AU BARGER, V PHILLIPS, RJN WHISNANT, K AF BARGER, V PHILLIPS, RJN WHISNANT, K TI REEXAMINATION OF NEUTRINO OSCILLATION SOLUTIONS TO THE SOLAR-NEUTRINO PROBLEM SO PHYSICAL REVIEW D LA English DT Article ID 3-NEUTRINO OSCILLATIONS; POSSIBLE EXPLANATION; RESONANT AMPLIFICATION; MATTER; EARTH; PUZZLE; FLUX; REGENERATION; DETECTOR; MOMENT AB A deficit of solar neutrinos compared to the standard solar model prediction has been measured in both the Homestake and Kamiokande-II experiments, with quite different detectors. We analyze the parameter space for oscillations of two neutrinos to find regions that can explain both experiments. Long-wavelength vacuum oscillation solutions are found with delta-m2 congruent-to 0.5-2.5 x 10(-10) eV2 and sin2 2-theta greater-than-or-similar-to 0.7. Matter-enhanced oscillation solutions are found for (i) nonadiabatic transitions having delta-m2-theta-2 almost-equal-to 10(-8) eV2 and and delta-m2 almost-equal-to 3 x 10(-8) -2 x 10(-5) eV2, and (ii) adiabatic transitions having delta-m2 almost-equal-to 10(-7) -10(-4) eV2 with sin2 2-theta greater-than-or-approximately 0.5. The two-neutrino long-wavelength and matter-enhanced solutions predict Ga-71 measurements in the ranges 50-80 and 5-115 solar-neutrino units (SNU), respectively, compared to 130 SNU without oscillations. We emphasize the distinctive features of each solution, including their predictions for future nu-e scattering experiments and detectable seasonal variations in the long-wavelength solutions. We also find the range of three-neutrino vacuum oscillation solutions. C1 RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP BARGER, V (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. NR 89 TC 82 Z9 82 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1110 EP 1128 DI 10.1103/PhysRevD.43.1110 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400018 ER PT J AU BERN, Z BLAU, SK MOTTOLA, E AF BERN, Z BLAU, SK MOTTOLA, E TI GENERAL COVARIANCE OF THE PATH INTEGRAL FOR QUANTUM-GRAVITY SO PHYSICAL REVIEW D LA English DT Article ID S-MATRIX; GAUGE-THEORIES; GEOMETRY; RENORMALIZATION; STRINGS; ANOMALIES; FIELD AB We construct the functional integration measure over four-geometries in the path integral for quantum gravity by means of a geometric, manifestly covariant approach, similar to that used by Polyakov for string theory. This generalizes the previous one-loop method of Mazur and Mottola to all orders of perturbation theory. We compare this measure to that obtained by the gauge-fixed method of Becchi-Rouet-Stora-Tyutin invariance exploited by Fujikawa and co-workers. The path integral defined by these two different procedures is one and the same. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. NR 43 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1212 EP 1222 DI 10.1103/PhysRevD.43.1212 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400027 ER PT J AU DUNNE, GV TRUGENBERGER, CA AF DUNNE, GV TRUGENBERGER, CA TI SELF-DUALITY AND NONRELATIVISTIC MAXWELL-CHERN-SIMONS SOLITONS SO PHYSICAL REVIEW D LA English DT Article ID MASSIVE GAUGE-THEORIES; CLASSICAL SOLUTIONS; STATISTICS; VORTICES; TERM AB We consider a model of nonrelativistic charged matter interacting with a massive Abelian gauge field and a neutral scalar field in (2 + 1)-dimensional space-time. As in the model considered by Jackiw and Pi with a pure Chern-Simons interaction, the model admits classical static self-dual solutions. These solutions are nontopological solitions which may be threaded by a number of vortices. Futhermore, these self-dual classical solutions are zero-energy configurations. C1 MIT, CTR THEORET PHYS, CAMBRIDGE, MA 02139 USA. UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET PHYS, LOS ALAMOS, NM 87545 USA. RP DUNNE, GV (reprint author), MIT, DEPT MATH, CAMBRIDGE, MA 02139 USA. NR 35 TC 26 Z9 26 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 EI 1550-2368 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1323 EP 1331 DI 10.1103/PhysRevD.43.1323 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400038 ER PT J AU DUNNE, GV JACKIW, R PI, SY TRUGENBERGER, CA AF DUNNE, GV JACKIW, R PI, SY TRUGENBERGER, CA TI SELF-DUAL CHERN-SIMONS SOLITONS AND 2-DIMENSIONAL NONLINEAR EQUATIONS SO PHYSICAL REVIEW D LA English DT Article ID REPRESENTATION-THEORY; GAUGE-THEORIES; SYSTEMS AB The nonlinear planar Schrodinger equation with additional coupling to non-Abelian Chern-Simons gauge fields possesses static, zero-energy solutions that satisfy self-dual equations. When the Schrodinger field is in the adjoint representation, the static equations comprise a two-dimensional reduction of the four-dimensional self-dual Yang-Mills system and various zero-curvature formulations. Well-known nonlinear equations of two-dimensional physics arise for the Schrodinger field, both in the adjoint and defining representations. Thus nonrelativistic matter interacting with Chern-Simons fields provides a unified dynamical framwork for these equations. C1 MIT,CTR THEORET PHYS,NUCL SCI LAB,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. BOSTON UNIV,DEPT PHYS,BOSTON,MA 02215. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET PHYS,LOS ALAMOS,NM 87545. RP DUNNE, GV (reprint author), MIT,DEPT MATH,CAMBRIDGE,MA 02139, USA. NR 28 TC 88 Z9 89 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1332 EP 1345 DI 10.1103/PhysRevD.43.1332 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400039 ER PT J AU FATYGA, BW KOSTELECKY, VA NIETO, MM TRUAX, DR AF FATYGA, BW KOSTELECKY, VA NIETO, MM TRUAX, DR TI SUPERCOHERENT STATES SO PHYSICAL REVIEW D LA English DT Article ID CAMPBELL-HAUSDORFF RELATIONS; SUPERSYMMETRIC QUANTUM-MECHANICS; 1ST-ORDER DIRAC-EQUATION; COHERENT STATES; MAGNETIC MONOPOLE; WAVE-FUNCTIONS; SUPERGROUPS; REPRESENTATIONS; SYSTEMS AB A general approach is presented for constructing coherent states for supersymmetric systems. It uses Roger's supermanifold formulation of supergroups to extend the group-theoretic method. Supercoherent states are explicitly obtained for the supersymmetric harmonic oscillator. They are shown to be eigenstates of the supersymmetric annihilation operator and to be minimum-uncertainty states. Two more-complex situations with extended physical supersymmetries are also considered: an electron moving in a constant magnetic field, and the electron-monopole system. The supercoherent states for these systems are found using super Baker-Campbell-Hausdorff relations and their interpretation is elucidated. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALGARY,DEPT CHEM,CALGARY T2N 1N4,ALBERTA,CANADA. RP FATYGA, BW (reprint author), INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405, USA. NR 53 TC 46 Z9 46 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1403 EP 1412 DI 10.1103/PhysRevD.43.1403 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400047 ER PT J AU BECKERSZENDY, R BRATTON, CB CADY, R CASPER, D DYE, ST GAJEWSKI, W GOLDHABER, M HAINES, TJ HALVERSON, PG JONES, TW KIELCZEWSKA, D KROPP, WR LEARNED, JG LOSECCO, JM MATSUNO, S MCGREW, C MUDAN, MS PRICE, L REINES, F SCHULTZ, J SOBEL, HW STONE, JL SULAK, LR SVOBODA, R WITTEL, F AF BECKERSZENDY, R BRATTON, CB CADY, R CASPER, D DYE, ST GAJEWSKI, W GOLDHABER, M HAINES, TJ HALVERSON, PG JONES, TW KIELCZEWSKA, D KROPP, WR LEARNED, JG LOSECCO, JM MATSUNO, S MCGREW, C MUDAN, MS PRICE, L REINES, F SCHULTZ, J SOBEL, HW STONE, JL SULAK, LR SVOBODA, R WITTEL, F TI SEARCH FOR CYGNUS-X-3 IN UNDERGROUND MUONS DURING THE 1989 RADIO OUTBURSTS USING THE IMB DETECTOR SO PHYSICAL REVIEW D LA English DT Note ID DIRECTION AB A search is made for underground muons from Cygnus X-3 with the Irvine-Michigan-Brookhaven IMB-3 detector around the time of the 1989 radio outbursts. No long-term pulsed signal is found in a sample of 11 117 underground muons collected from the direction of Cygnus X-3. We place an upper limit of 3 x 10(-10) cm-2 sec-1 on the flux of underground muons from Cygnus X-3. C1 UNIV CALIF IRVINE,IRVINE,CA 92717. UNIV MICHIGAN,ANN ARBOR,MI 48109. BROOKHAVEN NATL LAB,UPTON,NY 11973. BOSTON UNIV,BOSTON,MA 02215. UNIV LONDON UNIV COLL,LONDON WC1E 6BT,ENGLAND. UNIV WARSAW,PL-00325 WARSAW,POLAND. CLEVELAND STATE UNIV,CLEVELAND,OH 44115. UNIV NOTRE DAME,NOTRE DAME,IN 46556. LOUISIANA STATE UNIV,BATON ROUGE,LA 70803. UNIV MARYLAND,COLLEGE PK,MD 20742. RP BECKERSZENDY, R (reprint author), UNIV HAWAII,HONOLULU,HI 96822, USA. RI Sobel, Henry/A-4369-2011 NR 18 TC 1 Z9 1 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1991 VL 43 IS 4 BP 1413 EP 1415 DI 10.1103/PhysRevD.43.1413 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400048 ER PT J AU NOTZOLD, D AF NOTZOLD, D TI GRAVITATIONAL EFFECTS OF GLOBAL TEXTURES SO PHYSICAL REVIEW D LA English DT Note AB A solution for the dynamics of global textures is obtained. Their gravitational field during the collapse and the subsequent evolution is found to be given solely by a space-time-dependent "deficit solid angle." The frequency shift of photons traversing this gravitational field is calculated. The observed isotropy of the microwave background constrains the texture symmetry-breaking scale to eta-0 less-than-or-similar-to 1 x 10(16) GeV. The space-time-dependent texture metric locally contracts the volume of three-space and thereby induces overdensities in homogeneous matter distributions. There are no gravitational forces unless matter has a nonzero angular momentum with respect to the texture origin. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP NOTZOLD, D (reprint author), UNIV CHICAGO,CTR ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 4 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 FEB 15 PY 1991 VL 43 IS 4 BP R961 EP R964 DI 10.1103/PhysRevD.43.R961 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX994 UT WOS:A1991EX99400001 ER PT J AU ZHANG, J TIEN, NC LIN, EW WIEDER, HH KU, WH TU, CW POKER, DB CHU, SNG AF ZHANG, J TIEN, NC LIN, EW WIEDER, HH KU, WH TU, CW POKER, DB CHU, SNG TI MOLECULAR-BEAM EPITAXIAL-GROWTH AND CHARACTERIZATION OF PSEUDOMORPHIC MODULATION-DOPED FIELD-EFFECT TRANSISTORS SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 17TH INTERNATIONAL CONF ON METALLURGICAL COATINGS / 8TH INTERNATIONAL CONF ON THIN FILMS CY APR 02-06, 1990 CL SAN DIEGO, CA ID CRITICAL LAYER THICKNESS; HETEROSTRUCTURES AB We have investigated the luminescent and device properties of pseudomorphic AlGaAs/InGaAs modulation-doped field effect transistors (MODFETs) with different InAs molar fractions in the InGaAs channel. Molecular beam epitaxy, which simultaneously deposits group III atoms and As4 molecules on the substrate surface, was used to grow the random alloy In(x)Ga(1-x)As channel layer for x less-than-or-equal-to 0.4, and migration-enhanced epitaxy (MEE), which alternatingly deposits group III atoms and As4 molecules on the surface, was used to grow sequential layers of InAs and GaAs in the channel region with large effective x (up to 0.5). For 1-mu-m gate length MODFETs with random alloy In(x)Ga(1-x)As channels the transconductance g(m) and saturation drain current I(dss) exhibit a maximum at x = 0.17 because of the superior electron transport properties of InGaAs compared with GaAs. g(m) and I(dss) decrease drastically for x higher than 0.32 as a result of misfit dislocation generation. The photoluminescence peaks of In(x)Ga(1-x)As channels of these MODFET samples show a similar trend, strong intensity for the In0.17Ga0.83As channel and very weak intensity for the In0.4Ga0.6As channel. However, MODFETs with a nominally (InAs)2(GaAs)2 channel grown by MEE exhibit higher g(m), I(dss) and photoluminescence intensity than those with an In0.4Ga0.6As channel. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP ZHANG, J (reprint author), UNIV CALIF SAN DIEGO,DEPT ELECT & COMP ENGN,MAIL CODE R-007,LA JOLLA,CA 92093, USA. RI Tien, Norman/E-7194-2012 NR 10 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD FEB 15 PY 1991 VL 196 IS 2 BP 295 EP 303 DI 10.1016/0040-6090(91)90373-6 PG 9 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA EZ270 UT WOS:A1991EZ27000014 ER PT J AU ATWOOD, WB AF ATWOOD, WB TI B IDENTIFICATION BY TOPOLOGY WITH THE SLD DETECTOR SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article RP ATWOOD, WB (reprint author), STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 36 EP 40 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000004 ER PT J AU JADACH, S WARD, BFL AF JADACH, S WARD, BFL TI MULTIPLE PHOTON-EMISSION AND B-QUARK ASYMMETRIES SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID CARLO C1 JAGIELLONIAN UNIV, INST PHYS, PL-31007 KRAKOW, POLAND. STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94305 USA. INT CTR THEORET PHYS, I-34100 TRIESTE, ITALY. RP JADACH, S (reprint author), UNIV TENNESSEE, DEPT PHYS & ASTRON, KNOXVILLE, TN 37996 USA. NR 10 TC 0 Z9 0 U1 1 U2 1 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 99 EP 103 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000012 ER PT J AU WARD, BFL AF WARD, BFL TI THEORETICAL UNCERTAINTIES IN SEMILEPTONIC B DECAY SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID MODEL; MASS C1 STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94305 USA. INT CTR THEORET PHYS, I-34100 TRIESTE, ITALY. RP WARD, BFL (reprint author), UNIV TENNESSEE, DEPT PHYS & ASTRON, KNOXVILLE, TN 37996 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 104 EP 107 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000013 ER PT J AU BERGER, EL AF BERGER, EL TI B PRODUCTION IN HADRON-COLLISIONS - THEORY SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID HEAVY-QUARK PRODUCTION; CROSS-SECTION; QCD; ENERGY RP BERGER, EL (reprint author), ARGONNE NATL LAB, DIV HIGH ENERGY PHYS, ARGONNE, IL 60439 USA. NR 27 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 119 EP 129 PG 11 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000015 ER PT J AU BARLETTA, WA AF BARLETTA, WA TI POSITRON INJECTORS FOR HIGH-LUMINOSITY STORAGE-RING COLLIDERS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article C1 UNIV CALIF LOS ANGELES, DEPT PHYS, LOS ANGELES, CA 90024 USA. RP BARLETTA, WA (reprint author), UNIV CALIF LOS ANGELES, LAWRENCE LIVERMORE NATL LAB, LOS ANGELES, CA 90024 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 172 EP 177 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000020 ER PT J AU MTINGWA, SK STRIKMAN, M AF MTINGWA, SK STRIKMAN, M TI B-FACTORY VIA CONVERSION OF 1-TEV ELECTRON-BEAMS INTO 1-TEV PHOTON BEAMS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article C1 LENINGRAD NUCL PHYS INST, LENINGRAD 188350, USSR. YEREVAN PHYS INST, YEREVAN 375036, ARMENIA, USSR. RP MTINGWA, SK (reprint author), ARGONNE NATL LAB, DIV HIGH ENERGY PHYS, ARGONNE, IL 60439 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 211 EP 217 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000024 ER PT J AU ZISMAN, MS AF ZISMAN, MS TI STUDY OF COLLECTIVE EFFECTS FOR THE APIARY COLLIDER SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article RP ZISMAN, MS (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DIV ACCELERATOR & FUS RES, BERKELEY, CA 94720 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 228 EP 244 PG 17 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000026 ER PT J AU ATWOOD, WB MOURS, B AF ATWOOD, WB MOURS, B TI B PHYSICS AT THE Z0 POLE SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article C1 LAB PHYS PARTICULES, ANNECY LE VIEUX, FRANCE. RP ATWOOD, WB (reprint author), STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 250 EP 261 PG 12 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000028 ER PT J AU ODDONE, P AF ODDONE, P TI B-FACTORIES - A PERSONAL OVERVIEW SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article RP ODDONE, P (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD FEB 14 PY 1991 VL 619 BP 299 EP 304 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FM050 UT WOS:A1991FM05000033 ER PT J AU LIN, WJ HARBOTTLE, G AF LIN, WJ HARBOTTLE, G TI GAMMA-RAY EMISSION INTENSITIES OF RA-226 IN EQUILIBRIUM WITH ITS DAUGHTER PRODUCTS SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-LETTERS LA English DT Article AB A Ra-226 source of known disintegration rate has been measured to determine the absolute gamma-ray emission intensities of members of its decay chain in radioactive equilibrium. The results are compared with other values from the literature. RP LIN, WJ (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 12 TC 16 Z9 16 U1 0 U2 1 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 FEB 14 PY 1991 VL 153 IS 2 BP 137 EP 149 DI 10.1007/BF02164874 PG 13 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA FB796 UT WOS:A1991FB79600007 ER PT J AU JORGENSEN, JD AF JORGENSEN, JD TI OXIDE SUPERCONDUCTORS - BRINGING OXYGEN TO ORDER SO NATURE LA English DT Editorial Material RP JORGENSEN, JD (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 8 TC 13 Z9 13 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 14 PY 1991 VL 349 IS 6310 BP 565 EP 566 DI 10.1038/349565a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EX570 UT WOS:A1991EX57000029 ER PT J AU WUOSMAA, AH REHM, KE GLAGOLA, BG HAPP, T KUTSCHERA, W WOLFS, FLH AF WUOSMAA, AH REHM, KE GLAGOLA, BG HAPP, T KUTSCHERA, W WOLFS, FLH TI NEUTRON TRANSFER AT LARGE DISTANCES IN THE SYSTEM S-36 + MO-92 SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION REACTIONS; CROSS-SECTIONS; BARRIER AB One- and two-neutron transfer reactions were studied in the system S-36 + Mo-92 at bombarding energies of 140 and 180 MeV. The angular distributions for the two-neutron transfer at large distances show exponential falloffs which depend on the bombarding energy and are less steep than expected from tunneling theories. This behavior can be explained by considering diffractive, rather than semiclassical scattering. RP WUOSMAA, AH (reprint author), ARGONNE NATL LAB,DEPT PHYS,ARGONNE,IL 60439, USA. NR 20 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 14 PY 1991 VL 255 IS 3 BP 316 EP 320 DI 10.1016/0370-2693(91)90772-I PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FA351 UT WOS:A1991FA35100003 ER PT J AU BERN, Z DUNBAR, DC GUENDELMAN, EI AF BERN, Z DUNBAR, DC GUENDELMAN, EI TI MULTIINSTANTON INTERACTIONS IN SPONTANEOUSLY BROKEN SU (2) GAUGE-THEORY SO PHYSICS LETTERS B LA English DT Article ID QUANTITATIVE THEORY; BARYON-NUMBER; LIQUID; UNIVERSE AB We present an effective action for instanton dipole-dipole interactions in spontaneously broken SU(2) gauge theory in four dimensions. C1 UNIV LIVERPOOL,DEPT APPL MATH & THEORET PHYS,LIVERPOOL L69 3BX,ENGLAND. RP BERN, Z (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,MS-B285,LOS ALAMOS,NM 87545, USA. OI dunbar, david/0000-0003-2433-1675 NR 20 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 14 PY 1991 VL 255 IS 3 BP 385 EP 392 DI 10.1016/0370-2693(91)90783-M PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FA351 UT WOS:A1991FA35100014 ER PT J AU Abreu, P Adam, W Adami, F Adye, T Akesson, T Alekseev, GD Allen, P Almehed, S Alted, F Alvsvaag, SJ Amaldi, U Anassontzis, E Apel, WD Asman, B Astier, P Augustin, JE Augustinus, A Baillon, P Bambade, P Bara, F Barbiellini, G Bardin, DY Baroncelli, A Barring, O Bartl, W Bates, MJ Baubillier, M Becks, KH Beeston, CJ Begalli, M Beilliere, P Belokopytov, I Beltran, P Benedic, D Benlloch, JM Berggren, M Bertrand, D Biagi, S Bianchi, F Bibby, JH Bilenky, MS Billoir, P Bjarne, J Bloch, D Bogolubov, PN Bollini, D Bolognese, T Bonapart, M Bonesini, M Booth, PSL Boratav, M Borgeaud, P Borner, H Bosio, C Botner, O Bouquet, B Bozzo, M Braibant, S Branchini, P Brand, KD Brenner, RA Bricman, C Brown, RCA Brummer, N Brunet, JM Bugge, L Buran, T Burmeister, H Buytaert, JAMA Caccia, M Calvi, M Rozas, AJC Campagne, JE Campion, A Camporesi, T Canale, V Cao, F Carroll, L Caso, C Castelli, E Gimenez, MVC Cattai, A Cavallo, FR Cerritp, L Charpentier, P Checchia, P Chelkov, GA Chevalier, L Chliapnikov, P Chorowicz, V Cirio, R Clara, MP Contreras, JL Contri, R Cosme, G Couchot, F Crawley, HB Crennell, D Crosetti, G Crosland, N Crozon, M Maestro, JC Czellar, S Dagoret, S Dahl-Jensen, E Dalmagne, B Dam, M Damgaard, G Darbo, G Daubie, E Dauncey, PD Davenport, M David, P De Angelis, A De Beer, M De Boeck, H De Clercq, C Laso, MDMD De Groot, N De La Vaissiere, C De Lotto, B Defoix, C Delikaris, D Delorme, S Delpierre, P Demaria, N Di Ciaccio, L Dijkstra, H Djama, F Dolbeau, J Doll, O Donszelmann, M Doroba, K Dracos, M Drees, J Dris, M Dulinski, W Dzhelyadin, R Eek, LO Eerola, PAM Ekelof, T Ekspong, G Engel, JP Falaleev, V Fassouliotis, D Fenyuk, A Alonso, MF Ferrer, A Filippas, TA Firestone, A Foeth, H Fokitis, E Folegati, P Fontanelli, F Forsbach, H Franek, B Fransson, KE Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R Fulda-Quenzer, F Furnival, K Furstenau, H Fuster, J Gago, JM Galeazzi, G Gamba, D Garcia, J Gasparini, U Gavillet, P Gazis, EN Gerber, JP Giacomelli, P Glitza, KW Gokieli, R Golovatyuk, VM Cadenas, JJGY Goobar, A Gopal, G Gorski, M Gracco, V Grant, A Grard, F Graziani, E Gritsaenko, IA Gros, MH Grosdidier, G Grossetete, B Gumenyuk, S Guy, J Hahn, F Hahn, M Haider, S Hajduk, Z Hakansson, A Hallgren, A Hamacher, K De Monchenault, GH Harris, FJ Heck, BW Herbst, I Hernandez, JJ Herquet, P Herr, H Higon, E Hilke, HJ Hodgson, SD Hofmokl, T Holmes, R Holmgren, SO Holthuizen, D Hooper, JE Houlden, M Hrubec, J Hulth, PO Hultqvist, K Husson, D Hyams, BD Ioannou, P Iversen, PS Jackson, JN Jalocha, P Jarlskog, G Jarry, P Jean-Marie, B Johansson, EK Johnson, D Jonker, M Jonsson, L Juillot, P Kadyrov, RB Kalkanis, G Kalmus, G Kantardjian, G Kapusta, F Kapusta, P Katsanevas, S Katsoufis, EC Keranen, R Kesteman, J Khomenko, BA King, B Klein, H Klempt, W Klovning, A Kluit, P Koehne, JH Koene, B Kokkinias, P Kopf, M Koratzinos, M Korcyl, K Korytov, AV Korzen, B Kostrikov, M Kourkoumelis, C Kreuzberger, T Krolikowski, J Kruener-Marquis, U Krupinski, W Kucewicz, W Kurvinen, K Laakso, MI Lambropoulos, C Lamsa, JW Lanceri, L Lapchine, V Lapin, V Laugier, JP Lauhakangas, R Laurikainen, P Leder, G Ledroit, F Lemonne, J Lenzen, G Lepeltier, V Letessier-Selvon, A Lieb, E Lillethun, E Lindgren, J Lippi, I Llosa, R Loerstad, B Lokajicek, M Loken, JG Aguera, MAL Lopez-Fernandez, A Los, M Loukas, D Lounis, A Lozano, JJ Lucock, R Lutz, P Lyons, L Maehlum, G Magnussen, N Maillard, J Maltezos, A Maltezos, S Mandl, F Marco, J Margoni, M Marin, JC Markou, A Mathis, L Motorras, F Matteuzzi, C Matthiae, G Mazzucato, M Mc Cubbin, M Mc Kay, R Mc Nulty, R Menichetti, E Meroni, C Meyer, WT Mitaroff, WA Mitselmakher, GV Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Myatt, G Naraghi, F Nau-Korzen, U Navarria, FL Negri, P Nielsen, BS Nijjhar, B Nikolaenko, V Obraztsov, V Orava, R Ouraou, A Pain, R Palka, H Papadopoulou, T Pape, L Passeri, A Pegoraro, M Perevozchikov, V Pernicka, M Perrotta, A Pimenta, M Pingot, O Pinsent, A Pol, ME Polok, G Poropat, P Privitera, P Pullia, A Pyyhtia, J Rademakers, AA Radojicic, D Ragazzi, S Range, WH Ratofg, PN Read, AL Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, M Ridky, J Roditi, I Romero, A Ronchese, P Rosenberg, EI Rossi, U Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W Ruhlmann, V Ruiz, A Saarikko, H Sacquin, Y Sanchez, E Sanchez, J Sannino, M Schaeffer, M Schneider, H Scuri, F Segar, AM Sekulin, R Sessa, M Sette, G Seufert, R Shellard, RC Siegrist, P Simonetti, S Simonetto, F Sissakian, AN Skaali, TB Skeens, J Skjevling, G Smith, GR Sosnowski, R Spassoff, TS Spiriti, E Squarcia, S Staeck, H Stanescu, C Stavropoulos, G Stichelbaut, F Stocchi, A Strauss, J Strub, R Stubenrauch, CI Szczekowski, M Szeptycka, M Szymanski, P Tavernier, S Theodosiou, G Tilquin, A Timmermans, J Timofeev, VG Tkatchev, LG Toet, DZ Topphol, AK Tortora, L Trainor, MT Treille, D Trevisan, U Trischuk, W Tristram, G Troncon, C Tsirou, A Tsyganov, EN Turala, M Turchetta, R Turluer, ML Tuuva, T Tyapkin, IA Tyndel, M Tzamarias, S Udo, F Ueberschaer, S Uvarov, VA Valenti, G Vallazza, E Ferrer, JAV Van Apeldoorn, GW Van Dam, P Van Doninck, WK Van Eijndhoven, N Vander Velde, C Varela, J Vaz, P Vegni, G Velasco, J Ventura, L Venus, W Verbeure, F Vertogradov, LS Vibert, L Vilanova, D Vlasov, EV Vodopyanov, AS Vollmer, M Voulgaris, G Voutilainen, M Vrba, V Wahlen, H Walck, C Waldner, F Wayne, M Wehr, A Weilhammer, P Werner, J Wetherell, AM Wickens, JH Wikne, J Wilkinson, GR Williams, WSC Winter, M Wormald, D Wormser, G Woschnagg, K Yamdagni, N Yepes, P Zaitsev, A Zalewska, A Zalewski, P Zarubin, PI Zevgolatakos, E Zhang, G Zimin, NI Zitoun, R Funchal, RZ Zumerle, G Zuniga, J AF Abreu, P Adam, W Adami, F Adye, T Akesson, T Alekseev, GD Allen, P Almehed, S Alted, F Alvsvaag, SJ Amaldi, U Anassontzis, E Apel, WD Asman, B Astier, P Augustin, JE Augustinus, A Baillon, P Bambade, P Bara, F Barbiellini, G Bardin, DY Baroncelli, A Barring, O Bartl, W Bates, MJ Baubillier, M Becks, KH Beeston, CJ Begalli, M Beilliere, P Belokopytov, I Beltran, P Benedic, D Benlloch, JM Berggren, M Bertrand, D Biagi, S Bianchi, F Bibby, JH Bilenky, MS Billoir, P Bjarne, J Bloch, D Bogolubov, PN Bollini, D Bolognese, T Bonapart, M Bonesini, M Booth, PSL Boratav, M Borgeaud, P Borner, H Bosio, C Botner, O Bouquet, B Bozzo, M Braibant, S Branchini, P Brand, KD Brenner, RA Bricman, C Brown, RCA Brummer, N Brunet, JM Bugge, L Buran, T Burmeister, H Buytaert, JAMA Caccia, M Calvi, M Rozas, AJC Campagne, JE Campion, A Camporesi, T Canale, V Cao, F Carroll, L Caso, C Castelli, E Gimenez, MVC Cattai, A Cavallo, FR Cerritp, L Charpentier, P Checchia, P Chelkov, GA Chevalier, L Chliapnikov, P Chorowicz, V Cirio, R Clara, MP Contreras, JL Contri, R Cosme, G Couchot, F Crawley, HB Crennell, D Crosetti, G Crosland, N Crozon, M Maestro, JC Czellar, S Dagoret, S Dahl-Jensen, E Dalmagne, B Dam, M Damgaard, G Darbo, G Daubie, E Dauncey, PD Davenport, M David, P De Angelis, A De Beer, M De Boeck, H De Clercq, C Laso, MDMD De Groot, N De La Vaissiere, C De Lotto, B Defoix, C Delikaris, D Delorme, S Delpierre, P Demaria, N Di Ciaccio, L Dijkstra, H Djama, F Dolbeau, J Doll, O Donszelmann, M Doroba, K Dracos, M Drees, J Dris, M Dulinski, W Dzhelyadin, R Eek, LO Eerola, PAM Ekelof, T Ekspong, G Engel, JP Falaleev, V Fassouliotis, D Fenyuk, A Alonso, MF Ferrer, A Filippas, TA Firestone, A Foeth, H Fokitis, E Folegati, P Fontanelli, F Forsbach, H Franek, B Fransson, KE Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R Fulda-Quenzer, F Furnival, K Furstenau, H Fuster, J Gago, JM Galeazzi, G Gamba, D Garcia, J Gasparini, U Gavillet, P Gazis, EN Gerber, JP Giacomelli, P Glitza, KW Gokieli, R Golovatyuk, VM Cadenas, JJGY Goobar, A Gopal, G Gorski, M Gracco, V Grant, A Grard, F Graziani, E Gritsaenko, IA Gros, MH Grosdidier, G Grossetete, B Gumenyuk, S Guy, J Hahn, F Hahn, M Haider, S Hajduk, Z Hakansson, A Hallgren, A Hamacher, K De Monchenault, GH Harris, FJ Heck, BW Herbst, I Hernandez, JJ Herquet, P Herr, H Higon, E Hilke, HJ Hodgson, SD Hofmokl, T Holmes, R Holmgren, SO Holthuizen, D Hooper, JE Houlden, M Hrubec, J Hulth, PO Hultqvist, K Husson, D Hyams, BD Ioannou, P Iversen, PS Jackson, JN Jalocha, P Jarlskog, G Jarry, P Jean-Marie, B Johansson, EK Johnson, D Jonker, M Jonsson, L Juillot, P Kadyrov, RB Kalkanis, G Kalmus, G Kantardjian, G Kapusta, F Kapusta, P Katsanevas, S Katsoufis, EC Keranen, R Kesteman, J Khomenko, BA King, B Klein, H Klempt, W Klovning, A Kluit, P Koehne, JH Koene, B Kokkinias, P Kopf, M Koratzinos, M Korcyl, K Korytov, AV Korzen, B Kostrikov, M Kourkoumelis, C Kreuzberger, T Krolikowski, J Kruener-Marquis, U Krupinski, W Kucewicz, W Kurvinen, K Laakso, MI Lambropoulos, C Lamsa, JW Lanceri, L Lapchine, V Lapin, V Laugier, JP Lauhakangas, R Laurikainen, P Leder, G Ledroit, F Lemonne, J Lenzen, G Lepeltier, V Letessier-Selvon, A Lieb, E Lillethun, E Lindgren, J Lippi, I Llosa, R Loerstad, B Lokajicek, M Loken, JG Aguera, MAL Lopez-Fernandez, A Los, M Loukas, D Lounis, A Lozano, JJ Lucock, R Lutz, P Lyons, L Maehlum, G Magnussen, N Maillard, J Maltezos, A Maltezos, S Mandl, F Marco, J Margoni, M Marin, JC Markou, A Mathis, L Motorras, F Matteuzzi, C Matthiae, G Mazzucato, M Mc Cubbin, M Mc Kay, R Mc Nulty, R Menichetti, E Meroni, C Meyer, WT Mitaroff, WA Mitselmakher, GV Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Myatt, G Naraghi, F Nau-Korzen, U Navarria, FL Negri, P Nielsen, BS Nijjhar, B Nikolaenko, V Obraztsov, V Orava, R Ouraou, A Pain, R Palka, H Papadopoulou, T Pape, L Passeri, A Pegoraro, M Perevozchikov, V Pernicka, M Perrotta, A Pimenta, M Pingot, O Pinsent, A Pol, ME Polok, G Poropat, P Privitera, P Pullia, A Pyyhtia, J Rademakers, AA Radojicic, D Ragazzi, S Range, WH Ratofg, PN Read, AL Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, M Ridky, J Roditi, I Romero, A Ronchese, P Rosenberg, EI Rossi, U Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W Ruhlmann, V Ruiz, A Saarikko, H Sacquin, Y Sanchez, E Sanchez, J Sannino, M Schaeffer, M Schneider, H Scuri, F Segar, AM Sekulin, R Sessa, M Sette, G Seufert, R Shellard, RC Siegrist, P Simonetti, S Simonetto, F Sissakian, AN Skaali, TB Skeens, J Skjevling, G Smith, GR Sosnowski, R Spassoff, TS Spiriti, E Squarcia, S Staeck, H Stanescu, C Stavropoulos, G Stichelbaut, F Stocchi, A Strauss, J Strub, R Stubenrauch, CI Szczekowski, M Szeptycka, M Szymanski, P Tavernier, S Theodosiou, G Tilquin, A Timmermans, J Timofeev, VG Tkatchev, LG Toet, DZ Topphol, AK Tortora, L Trainor, MT Treille, D Trevisan, U Trischuk, W Tristram, G Troncon, C Tsirou, A Tsyganov, EN Turala, M Turchetta, R Turluer, ML Tuuva, T Tyapkin, IA Tyndel, M Tzamarias, S Udo, F Ueberschaer, S Uvarov, VA Valenti, G Vallazza, E Ferrer, JAV Van Apeldoorn, GW Van Dam, P Van Doninck, WK Van Eijndhoven, N Vander Velde, C Varela, J Vaz, P Vegni, G Velasco, J Ventura, L Venus, W Verbeure, F Vertogradov, LS Vibert, L Vilanova, D Vlasov, EV Vodopyanov, AS Vollmer, M Voulgaris, G Voutilainen, M Vrba, V Wahlen, H Walck, C Waldner, F Wayne, M Wehr, A Weilhammer, P Werner, J Wetherell, AM Wickens, JH Wikne, J Wilkinson, GR Williams, WSC Winter, M Wormald, D Wormser, G Woschnagg, K Yamdagni, N Yepes, P Zaitsev, A Zalewska, A Zalewski, P Zarubin, PI Zevgolatakos, E Zhang, G Zimin, NI Zitoun, R Funchal, RZ Zumerle, G Zuniga, J CA DELPHI Collaboration TI EXPERIMENTAL-STUDY OF THE TRIPLE-GLUON VERTEX SO PHYSICS LETTERS B LA English DT Article ID LUND MONTE-CARLO; NON-ABELIAN NATURE; 4-JET EVENTS; JET FRAGMENTATION; E+E ANNIHILATION; 3-GLUON VERTEX; QCD; PHYSICS; COLLISIONS; DECAYS AB In four-jet events from e+e- --> Z0 --> multihadrons one can separate the three principal contributions from the triple-gluon vertex, double gluon-bremsstrahlung and the secondary quark-antiquark production, using the shape of the two-dimensional angular distributions in the generalized Nachtmann-Reiter angle theta-NR* and the opening angle of the secondary jets. Thus one can identify directly the contribution from the triple-gluon vertex without comparison with a specific non-QCD model. Applying this new method to events taken with the DELPHI-detector we get for the ratio of the colour factor N(C) to the fermionic Casimir operator C(F): N(C)/C(F) = 2.55 +/- 0.55(stat.) +/- 0.4(fragm. + models) +/- 0.2(error in bias) in agreement with the value 2.25 expected in QCD from N(C) = 3 and C(F) = 4/3. C1 LIP, P-1000 Lisbon, PORTUGAL. Oesterreich Akad Wissensch, Inst Hochenergiephys, A-1050 Vienna, AUSTRIA. CEN Saclay, DPhPE, F-91191 Gif Sur Yvette, FRANCE. Rutherford Appleton Lab, Chilton OXll OQX, Didcot, ENGLAND. Univ Lund, Dept Phys, S-22363 Lund, SWEDEN. Joint Inst Nucl Res, SU-101000 Moscow, RUSSIA. Univ Valencia, Inst Fis Corpuscular IFIC, Ctr Mixto, CSIC, E-46100 Burjassot, Valencia, SPAIN. Univ Bergen, Dept Phys, N-5007 Bergen, NORWAY. CERN, CH-1211 Geneva 23, SWITZERLAND. Univ Athens, Phys Lab, GR-10680 Athens, GREECE. Univ Karlsruhe, Inst Expt Kernphys, W-7500 Karlsruhe 1, GERMANY. Univ Stockholm, Inst Phys, S-11346 Stockholm, SWEDEN. Univ Paris 06, LPNHE, F-75230 Paris 05, FRANCE. Univ Paris 07, LPNHE, F-75230 Paris 05, FRANCE. Univ Paris Sud, Lab Accelerateur Lineaire, F-91405 Orsay, FRANCE. Univ Trieste, Dipartimento Fis, I-34127 Trieste, ITALY. Ist Nazl Fis Nucl, I-34127 Trieste, ITALY. Univ Udine, Ist Fis, I-33100 Udine, ITALY. Ist Nazl Fis Nucl, Ist Super Sanita, I-01161 Rome, ITALY. Univ Rome 2, Dipartimento Fis, I-00173 Rome, ITALY. Ist Nazl Fis Nucl, I-00173 Rome, ITALY. Univ Oxford, Nucl Phys Lab, Oxford OX1 3RH, ENGLAND. Univ Wuppertal, Fachbereich Phys, W-5600 Wuppertal 1, GERMANY. Univ Genoa, Dipartimento Fis, I-16146 Genoa, ITALY. Ist Nazl Fis Nucl, I-16146 Genoa, ITALY. Coll France, Lab Phys Corpusculaire, F-75231 Paris 05, FRANCE. Inst High Energy Phys, SU-142 284 Protvino, Moscow Region, RUSSIA. NRC Demokritos, Inst Nucl Phys, GR-15310 Athens, GREECE. CRN Grp DELPHI, Div Hautes Energies, F-67037 Strasbourg, FRANCE. LEPSI, F-67037 Strasbourg, FRANCE. Univ Instelling Antwerp, Dept Phys, B-2610 Wilrijk, BELGIUM. ULB VUB, IIHE, B-1050 Brussels, BELGIUM. Univ Etat Mons, Fac Sci, Serv Phys Part Elem, B-7000 Mons, BELGIUM. Univ Liverpool, Dept Phys, Liverpool L69 3BX, Merseyside, ENGLAND. Univ Turin, Dipartimento Fis Sperimentale, I-10125 Turin, ITALY. Ist Nazl Fis Nucl, I-10125 Turin, ITALY. Univ Bologna, Dipartimento Fis, I-40126 Bologna, ITALY. Ist Nazl Fis Nucl, I-40126 Bologna, ITALY. NIKHEF H, NL-1009 DB Amsterdam, NETHERLANDS. Univ Milan, Dipartmento Fis, I-20133 Milan, ITALY. Ist Nazl Fis Nucl, I-20133 Milan, ITALY. Univ Uppsala, Dept Radiat Sci, S-75121 Uppsala, SWEDEN. Univ Helsinki, Dept High Energy Phys, SF-00170 Helsinki 17, FINLAND. Univ Oslo, Dept Phys, N-1000 Oslo 3, NORWAY. Univ Santander, Fac Ciencias, E-39005 Santander, SPAIN. Univ Padua, Dipartimento Fis, I-35131 Padua, ITALY. Ist Nazl Fis Nucl, I-35131 Padua, ITALY. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Niels Bohr Inst, DK-2100 Copenhagen 0, DENMARK. Univ Warsaw, PL-00681 Warsaw, POLAND. Inst Nucl Studies, PL-00681 Warsaw, POLAND. Natl Tech Univ, Dept Phys, GR-15773 Athens, GREECE. Inst Nucl Phys, High Energy Phys Lab, PL-30055 Krakow 30, POLAND. RP Abreu, P (reprint author), LIP, Av Elias Garcia 14-1e, P-1000 Lisbon, PORTUGAL. RI Pimenta, Mario/M-1741-2013; Zuniga, Juan/P-4385-2014; Vaz, Pedro/K-2464-2013; Ragazzi, Stefano/D-2463-2009; Rovelli, Tiziano/K-4432-2015; Lozano-Bahilo, Julio/F-4881-2016; Hernandez-Rey, Juan Jose/N-5955-2014; Abreu, Pedro/L-2220-2014; Barao, Fernando/O-2357-2016; Ruiz, Alberto/E-4473-2011; Zaitsev, Alexandre/B-8989-2017; Ridky, Jan/H-6184-2014; Varela, Joao/K-4829-2016; OI Pimenta, Mario/0000-0002-2590-0908; Zuniga, Juan/0000-0002-1041-6451; Vaz, Pedro/0000-0002-7186-2359; Ragazzi, Stefano/0000-0001-8219-2074; Rovelli, Tiziano/0000-0002-9746-4842; Lozano-Bahilo, Julio/0000-0003-0613-140X; Hernandez-Rey, Juan Jose/0000-0002-1527-7200; Abreu, Pedro/0000-0002-9973-7314; Barao, Fernando/0000-0002-8346-9941; Ruiz, Alberto/0000-0002-3639-0368; Zaitsev, Alexandre/0000-0002-4961-8368; Demaria, Natale/0000-0003-0743-9465; Bonesini, Maurizio/0000-0001-5119-1896; Ridky, Jan/0000-0001-6697-1393; Sannino, Mario/0000-0001-7700-8383; De Angelis, Alessandro/0000-0002-3288-2517; Varela, Joao/0000-0003-2613-3146; De Lotto, Barbara/0000-0003-3624-4480; Benlloch Baviera, Jose Maria/0000-0001-6073-1436; Contreras Gonzalez, Jose Luis/0000-0001-7282-2394; Matorras, Francisco/0000-0003-4295-5668 NR 24 TC 45 Z9 45 U1 0 U2 12 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 FEB 14 PY 1991 VL 255 IS 3 BP 466 EP 476 DI 10.1016/0370-2693(91)90796-S PG 11 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FA351 UT WOS:A1991FA35100027 ER PT J AU SCHWARZ, CL BULLOCK, RM CREUTZ, C AF SCHWARZ, CL BULLOCK, RM CREUTZ, C TI INTRINSIC BARRIERS TO ATOM TRANSFER - SELF-EXCHANGE REACTIONS OF CPM(CO)3X/CPM(CO)3- HALIDE COUPLES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-TRANSFER REACTIONS; ORGANOTRANSITION-METAL HYDRIDES; NUCLEAR MAGNETIC-RESONANCE; ALKYL MOLYBDENUM COMPLEXES; BOND-DISSOCIATION ENERGIES; M = MO; GAS-PHASE; REDUCTIVE ELIMINATION; CARBONYL ANIONS; KINETICS AB The self-exchange reactions were followed by H-1 NMR spectroscopy: For the X = 1 complexes, standard line width measurements yield (M = Mo) k(298) = 1.5 x 10(4) M-1 s-1 (DELTA-H = 6.4 (+/- 0.4) kcal mol-1, DELTA-S = -18 (+/- 1.5) cal K-1 mol-1) and (M = W) k(298) = 4.5 x 10(3) M-1 s-1 (DELTA-H = 7.5 (+/- 0.1) kcal mol-1, DELTA-S = -16.8 (+/- 0.5) cal K-1 mol-1). For the X = Br complexes, magnetization-transfer experiments yield (M = Mo) k(298) = 1.6 x 10(1) M-1 s-1 (DELTA-H = 12.1 (+/- 4.5) kcal mol-1, DELTA-S = -12 (+/- 15) cal K-1 mol-1) and (M = W) k(298) = 1.5 M-1 s-1 (DELTA-H = 15.1 (+/- 5.2) kcal mol-1, DELTA-S = -7 (+/- 16) cal K-1 mol-1); H-1 NMR longitudinal relaxation times T1 for the Cp groups of the reactants are typically 40 s. The X = Cl systems were studied by conventional techniques, with the rates of "transfer" of Cp-d5 from (Cp-d5)W(CO)3- to CpW(CO)3Cl being monitored; for M = Mo, k(298) = 9.0 x 10(-2) M-1 s-1 (DELTA-H = 18.9 (+/- 1.0) kcal mol-1, DELTA-S = 0 (+/- 4) cal K-1 mol-1) and for M = W, k(298) = 2.1 x 10(-3) M-1 s-1 (DELTA-H = 17.7 (+/- 3.3) kcal mol-1, DELTA-S = -11 (+/- 11) cal K-1 mol-1). For X = CH3, the CpW(CO)3-/CpW(CO)3CH3 self-exchange rate constant, also determined by monitoring rates of "transfer" of Cp-d5 from (Cpd5)W(CO)3- to CpW(CO)3X, is almost-equal-to 1 x 10(-5) M-1 s-1 at 335 K. The latter self-exchange reaction is discussed in terms of the intrinsic barrier for oxidative addition to the anion. For the X = halogen exchanges, the role of the M(I) ("metal radical") state is considered, and it is concluded that the latter isovalent state is not an intermediate for these systems. However, the isovalent state may serve to stabilize the transition state for two-electron transfer between the metal centers through configuration interaction. Our results, taken with those for other X = halogen systems, indicate that effective transfer of X+ may be intrinsically rapid when both reactants are 18-electron species and steric factors are favorable. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RI Bullock, R. Morris/L-6802-2016 OI Bullock, R. Morris/0000-0001-6306-4851 NR 83 TC 32 Z9 32 U1 0 U2 1 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 FEB 13 PY 1991 VL 113 IS 4 BP 1225 EP 1236 DI 10.1021/ja00004a024 PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA EX603 UT WOS:A1991EX60300024 ER PT J AU YAO, XQ FRANZEN, HF AF YAO, XQ FRANZEN, HF TI NB1.72TA3.28S2 - A NOVEL PHASE IN THE TA-NB-S TERNARY-SYSTEM WITH A LAYERED STRUCTURE SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 10 TC 45 Z9 45 U1 1 U2 1 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 FEB 13 PY 1991 VL 113 IS 4 BP 1426 EP 1427 DI 10.1021/ja00004a061 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA EX603 UT WOS:A1991EX60300061 ER PT J AU BOHNE, C ALNAJJAR, MS GRILLER, D SCAIANO, JC AF BOHNE, C ALNAJJAR, MS GRILLER, D SCAIANO, JC TI EXAMPLE OF DIFFUSION-LIMITED BEHAVIOR IN THE REACTION OF A GEMINATE RADICAL PAIR IN MICELLES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID MAGNETIC-FIELD; FLASH-PHOTOLYSIS; DECAY; PHOTOCHEMISTRY; FLUORESCENCE; RATES C1 NATL RES COUNCIL CANADA, DIV CHEM, OTTAWA K1A 0R6, ONTARIO, CANADA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 26 TC 26 Z9 26 U1 0 U2 3 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 FEB 13 PY 1991 VL 113 IS 4 BP 1444 EP 1445 DI 10.1021/ja00004a072 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA EX603 UT WOS:A1991EX60300072 ER PT J AU KAKURAI, K STEINER, M PYNN, R KJEMS, JK AF KAKURAI, K STEINER, M PYNN, R KJEMS, JK TI INELASTIC POLARIZED NEUTRON-SCATTERING FROM S=1 ANTIFERROMAGNETIC CSNICL3 IN AN APPLIED FIELD SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID SINGLET-GROUND-STATE; MONTE-CARLO CALCULATION; HEISENBERG-ANTIFERROMAGNET; HALDANE CONJECTURE; SPIN CHAINS; MAGNETIC-PROPERTIES; ANTI-FERROMAGNET; LINEAR-CHAIN; GAP; EXCITATIONS AB We report inelastic polarized neutron scattering measurements of the excitations in the S = 1, quasi-one-dimensional antiferromagnet CsNiCl3 with applied magnetic field. A field up to 5.9 T was applied perpendicular to the chain direction and the field dependence of spin excitation modes at wave vectors corresponding to the one-dimensional zone centre (i.e. (xi, xi, 1)) was studied. Near the antiferromagnetic ordering point Q = (1/3, 1/3, 1) two types of field dependence are observed. The behaviour of the higher energy mode suggests that it is the novel longitudinal mode recently proposed by Affleck. The application of the field also reveals a near-degeneracy of the excitations observed at Q = (0, 0, 1) in zero field. This degeneracy is incompatible with the result of the classical spin wave theory based on the Heisenberg Hamiltonian with a single-site anisotropy. C1 UNIV MAINZ,INST PHYS,W-6500 MAINZ,GERMANY. UNIV CALIF LOS ALAMOS SCI LAB,LANSCE,LOS ALAMOS,NM 87545. RISO NATL LAB,DK-4000 ROSKILDE,DENMARK. RP KAKURAI, K (reprint author), TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 980,JAPAN. NR 46 TC 65 Z9 67 U1 1 U2 3 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 FEB 11 PY 1991 VL 3 IS 6 BP 715 EP 726 DI 10.1088/0953-8984/3/6/008 PG 12 WC Physics, Condensed Matter SC Physics GA EX874 UT WOS:A1991EX87400008 ER PT J AU MACH, H WOHN, FK MOLNAR, G SISTEMICH, K HILL, JC MOSZYNSKI, M GILL, RL KRIPS, W BRENNER, DS AF MACH, H WOHN, FK MOLNAR, G SISTEMICH, K HILL, JC MOSZYNSKI, M GILL, RL KRIPS, W BRENNER, DS TI RETARDATION OF B(E2,01+-]21+) RATES IN SR-90 96 AND STRONG SUBSHELL CLOSURE EFFECTS IN THE A-APPROXIMATELY-100 REGION SO NUCLEAR PHYSICS A LA English DT Article ID PICOSECOND LIFETIME MEASUREMENTS; SQUARE CHARGE RADII; GAMMA ANGULAR-CORRELATIONS; NEUTRON-RICH NUCLEI; EVEN-EVEN NUCLIDES; ISOTOPE SHIFTS; HYPERFINE-STRUCTURE; LASER SPECTROSCOPY; NPNN SYSTEMATICS; DROPLET-MODEL AB Lifetimes of low-lying levels in Sr-90, Sr-92, Sr-94, Sr-96 were measured using a recently developed beta-gamma-gamma fast timing method. The deduced B(E2; 0(1)+ --> 2(1)+) rates which fill the N = 52-58 gap in the known B(E2) strengths for Sr-78-100, are exceptionally low, approximately 8 W.u., and provide evidence for a strong Z = 38 subshell effect extending from N = 50 to N = 58. Furthermore, these rates establish a close similarity between Sr-88-96 and Zr-90-98 nuclei, which form a region of the lowest B(E2) values (for nuclei with A > 56) second only to Pb-204-210. The Sr B(E2) values are compared with predictions based on various global, regional and local systematics as well as the results of laser spectroscopic measurements. The discrepancy with the latter is explained as due to octupole vibrational collectivity. Unique to the Q(0) systematics in the Sr region is a sudden shape change from spherical to deformed at N = 60. This transformation is so remarkably large and abrupt for Sr nuclei that is suggests a "phase change" in Sr collectivity. C1 UNIV COLOGNE,INST KERNPHYS,W-5000 COLOGNE 41,GERMANY. FORSCHUNGSZENTRUM JULICH,INST KERNPHYS,W-5170 JULICH,GERMANY. INST ISOTOPES,H-1525 BUDAPEST,HUNGARY. INST NUCL STUDIES,PL-05400 OTWOCK,POLAND. CLARK UNIV,WORCESTER,MA 01610. BROOKHAVEN NATL LAB,UPTON,NY 11973. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP MACH, H (reprint author), UNIV UPPSALA,STUDSVIK NEUTRON RES LAB,S-61182 NYKOPING,SWEDEN. NR 67 TC 129 Z9 130 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD FEB 11 PY 1991 VL 523 IS 2 BP 197 EP 227 DI 10.1016/0375-9474(91)90001-M PG 31 WC Physics, Nuclear SC Physics GA FB250 UT WOS:A1991FB25000001 ER EF