FN Thomson Reuters Web of Science™ VR 1.0 PT J AU GAO, W WESELY, ML LEE, IY AF GAO, W WESELY, ML LEE, IY TI A NUMERICAL STUDY OF THE EFFECTS OF AIR CHEMISTRY ON FLUXES OF NO, NO2, AND O3 NEAR THE SURFACE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PLANETARY BOUNDARY-LAYER; DRY DEPOSITION; PROFILES; VEGETATION; EVOLUTION; EMISSION; FOREST; GASES; O-3 AB A numerical model was developed to investigate modifications of the vertical fluxes of NO, NO2, and O3 by rapid atmospheric chemical reactions in a horizontally homogeneous, neutrally stratified atmospheric surface layer. The one-dimensional model coupled second-order budget equations for fluxes with conservation equations for concentrations and incorporated simplified homogeneous gas kinetics describing the photolysis of NO2 and the recombination of NO and O3. The effects of hydrocarbons were ignored. Simulations were carried out for representative chemical concentrations at the top boundary, moderate atmospheric turbulent mixing, surface removal rates typical for vegetation in the daytime, and a range of NO emission rates from the surface. Results indicate that the effective eddy diffusivity for NO and NO2 can be significantly altered by chemical reactions and that the fluxes of NO and NO2 can vary strongly with height but that the impact of rapid atmospheric chemical reactions on O3 is small relative to its total flux. When the NO2-to-NO concentration ratio aloft is greater than the ratio for the photostationary state, photodecomposition of NO2 dominates the reaction cycle. In this case, NO flux increases with height even when the flux at the surface is zero, while the downward NO2 flux increases in magnitude with height and the magnitude of the downward O3 flux decreases. When the value of [NO2]/[NO] aloft is smaller than the photostationary value, these trends with height are reversed. Emission of NO at the surface strongly influences NO flux near the surface, while chemical reactions tend to determine the flux at heights above a few meters. A significant effect on NO2 occurs at the intermediate heights, but the relative change in O3 flux is minor. RP GAO, W (reprint author), ARGONNE NATL LAB, DIV ENVIRONM RES, BLDG 203, ARGONNE, IL 60439 USA. NR 26 TC 56 Z9 57 U1 0 U2 6 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 OCT 20 PY 1991 VL 96 IS D10 BP 18761 EP 18769 DI 10.1029/91JD02106 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GM167 UT WOS:A1991GM16700019 ER PT J AU SASTRY, SS HEARST, JE AF SASTRY, SS HEARST, JE TI STUDIES ON THE INTERACTION OF T7 RNA-POLYMERASE WITH A DNA-TEMPLATE CONTAINING A SITE-SPECIFICALLY PLACED PSORALEN CROSS-LINK .1. CHARACTERIZATION OF ELONGATION COMPLEXES SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article ID RIBONUCLEIC-ACID POLYMERASE; ESCHERICHIA-COLI; TRANSCRIPTION INITIATION; TERNARY COMPLEXES; WAVELENGTH DEPENDENCE; PROMOTER; BINDING; PROTEIN; BACTERIOPHAGE-T7; TERMINATION C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM,DIV CHEM BIODYNAM,BERKELEY,CA 94720. FU NCEH CDC HHS [NIEHS 07075-11]; NIGMS NIH HHS [GM 41911] NR 60 TC 41 Z9 42 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD OCT 20 PY 1991 VL 221 IS 4 BP 1091 EP 1110 DI 10.1016/0022-2836(91)90921-R PG 20 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GN210 UT WOS:A1991GN21000006 PM 1942044 ER PT J AU SASTRY, SS HEARST, JE AF SASTRY, SS HEARST, JE TI STUDIES ON THE INTERACTION OF T7 RNA-POLYMERASE WITH A DNA-TEMPLATE CONTAINING A SITE-SPECIFICALLY PLACED PSORALEN CROSS-LINK .2. STABILITY AND SOME PROPERTIES OF ELONGATION COMPLEXES SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE T7 RNA POLYMERASE; ELONGATION COMPLEXES; TRANSCRIPTION; PROTEIN-DNA INTERACTIONS; MOBILITY SHIFT ASSAY; PSORALEN ID ESCHERICHIA-COLI; BACTERIOPHAGE-T7; PROMOTER; TRANSCRIPTION; INITIATION; BINDING; EXPRESSION; PROTEIN; GENE C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM,DIV CHEM BIODYNAM,BERKELEY,CA 94720. FU NCEH CDC HHS [NIEHS 07075-11]; NIGMS NIH HHS [GM 41911] NR 32 TC 30 Z9 30 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD OCT 20 PY 1991 VL 221 IS 4 BP 1111 EP 1125 DI 10.1016/0022-2836(91)90922-S PG 15 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GN210 UT WOS:A1991GN21000007 PM 1942045 ER PT J AU SKRZYPCZAKJANKUN, E CARPEROS, VE RAVICHANDRAN, KG TULINSKY, A WESTBROOK, M MARAGANORE, JM AF SKRZYPCZAKJANKUN, E CARPEROS, VE RAVICHANDRAN, KG TULINSKY, A WESTBROOK, M MARAGANORE, JM TI STRUCTURE OF THE HIRUGEN AND HIRULOG-1 COMPLEXES OF ALPHA-THROMBIN SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE ALPHA-THROMBIN; HIRUGEN; HIRULOG-1; HIRUDIN; THROMBIN COMPLEXES ID NUCLEAR MAGNETIC-RESONANCE; RECOMBINANT HIRUDIN; CRYSTAL-STRUCTURE; BINDING-SITE; INHIBITION; PEPTIDE; FIBRINOGEN; IDENTIFICATION; STABILIZATION; CONFORMATION C1 MICHIGAN STATE UNIV, DEPT CHEM, E LANSING, MI 48824 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. BIOGEN, CAMBRIDGE, MA 02142 USA. FU NHLBI NIH HHS [HL43229] NR 46 TC 255 Z9 259 U1 0 U2 7 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD OCT 20 PY 1991 VL 221 IS 4 BP 1379 EP 1393 PG 15 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GN210 UT WOS:A1991GN21000024 PM 1942057 ER PT J AU MORGAN, GL RING, NSP LISOWSKI, PW BOYER, KG ENGE, HA KOWALSKI, SB HOLSINGER, RF LOWN, RR IVERSEN, SG TINSLEY, JR BALTRUSAITIS, RM AF MORGAN, GL RING, NSP LISOWSKI, PW BOYER, KG ENGE, HA KOWALSKI, SB HOLSINGER, RF LOWN, RR IVERSEN, SG TINSLEY, JR BALTRUSAITIS, RM TI BROAD RANGE ELECTRON SPECTROMETER USING PERMANENT-MAGNETS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Compact electron spectrometers have been designed and fabricated using permanent magnets. The design allows a very broad range of electron momenta (1 to 25 MeV/c) with resolutions dual to the greater of either 1% or 0.1 MeV/c. Two types of magnet material have been employed (Sm-Co and Nd-Fe) to build two models of the spectrometer. Measurements of the spectrometer characteristics are compared to design calculations. C1 MIT,CAMBRIDGE,MA 02139. FIELD EFFECTS INC,ACTON,MA 01720. EG&G ENERGY MEASUREMENTS INC,SANTA BARBARA OPERAT,SANTA BARBARA,CA 93177. RP MORGAN, GL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 11 TC 11 Z9 11 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 20 PY 1991 VL 308 IS 3 BP 544 EP 556 DI 10.1016/0168-9002(91)90067-Z PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GN333 UT WOS:A1991GN33300007 ER PT J AU LI, Z CHEN, W KRANER, HW AF LI, Z CHEN, W KRANER, HW TI EFFECTS OF FAST-NEUTRON RADIATION ON THE ELECTRICAL-PROPERTIES OF SILICON DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID DAMAGE; CAPACITANCE; JUNCTIONS; CENTERS AB Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (phi-n greater-than-or-equal-to 10(12) n/cm2), C-V characteristics of detectors with high resistivities (p greater-than-or-equal-to 1 k-OMEGA cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN2 temperature) detectors shows three anneal stages, while two anneal stages were observed in elevated temperature anneal. RP LI, Z (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 19 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 20 PY 1991 VL 308 IS 3 BP 585 EP 595 DI 10.1016/0168-9002(91)90071-W PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GN333 UT WOS:A1991GN33300011 ER PT J AU ARENDT, RH GARBAUSKAS, MF MEYER, CA ROTELLA, FJ JORGENSEN, JD HITTERMAN, RL AF ARENDT, RH GARBAUSKAS, MF MEYER, CA ROTELLA, FJ JORGENSEN, JD HITTERMAN, RL TI THERMAL-EXPANSION MEASUREMENTS USING NEUTRON-DIFFRACTION OF BI2CASR2CU2OX SO PHYSICA C LA English DT Article AB The differential thermal expansion of Bi2CaSr2Cu2Ox, Bi-(2122), has been measured using high-temperature neutron powder diffraction in air, 0.980% oxygen in nitrogen, and pure argon. Thermal expansion in the c-axis direction is greater by a factor of about 1.4 than that in either the a- or b-axis direction for all sample environments. The neutron results for Bi-(2122) in air are compared with results from similar X-ray powder diffraction measurements. C1 ARGONNE NATL LAB,DIV IPNS,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP ARENDT, RH (reprint author), GE,CORP RES & DEV,SCHENECTADY,NY 12301, USA. NR 14 TC 33 Z9 33 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD OCT 20 PY 1991 VL 182 IS 1-3 BP 73 EP 78 DI 10.1016/0921-4534(91)90459-C PG 6 WC Physics, Applied SC Physics GA GP372 UT WOS:A1991GP37200012 ER PT J AU FERRIS, KF FRANZ, JA SOSA, CP BARTLETT, RJ AF FERRIS, KF FRANZ, JA SOSA, CP BARTLETT, RJ TI THEORETICAL INVESTIGATION OF THE RELATIVE STABILITIES OF SINGLET AND TRIPLET DISULFIDES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULAR-STRUCTURE; BARRIERS; ABINITIO; ROTATION; ENERGIES; MODEL; H2S2 AB Ab initio molecular orbital calculations have been performed on the singlet (1A) and triplet (3A(u)) states of hydrogen persulfide (HSSH) at the SCF and post-SCF levels using a double zeta basis set augmented with polarization functions. The relative energies for this system were computed by many-body perturbation theory (MBPT) and coupled-cluster (CC) methods, indicating that the singlet and triplet states are both lower in energy than the isolated HS fragments. Structural information for 1[HSSH] determined at the SCF and post-SCF levels are in good agreement with experiment. The triplet state is very weakly bound (< 5 kcal/mol) and lies approximately 50 kcal/mol above the singlet state. C1 UNIV FLORIDA, QUANTUM THEORY PROJECT, GAINESVILLE, FL 32611 USA. RP FERRIS, KF (reprint author), PACIFIC NW LAB, CTR MAT & CHEM SCI, RICHLAND, WA 99352 USA. RI Bartlett, Rodney/F-6781-2011 OI Bartlett, Rodney/0000-0003-3865-9639 NR 27 TC 7 Z9 7 U1 1 U2 5 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 OCT 18 PY 1991 VL 185 IS 3-4 BP 251 EP 255 DI 10.1016/S0009-2614(91)85056-3 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GN029 UT WOS:A1991GN02900014 ER PT J AU SMITH, RD UDSETH, HR BARINAGA, CJ EDMONDS, CG AF SMITH, RD UDSETH, HR BARINAGA, CJ EDMONDS, CG TI INSTRUMENTATION FOR HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS MASS-SPECTROMETRY SO JOURNAL OF CHROMATOGRAPHY LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL SYMP ON HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS ( HPCE 91 ) CY FEB 03-06, 1991 CL SAN DIEGO, CA ID ELECTROSPRAY IONIZATION INTERFACE; ATOM-BOMBARDMENT INTERFACE; ZONE ELECTROPHORESIS; ISOTACHOPHORESIS; PROTEINS; POLYPEPTIDES; PEPTIDE AB An automated, commercially available capillary electrophoresis (CE) instrument was modified for interfacing with electrospray ionization mass spectrometry (ESI-MS). A Beckman P/ACE 2000 CE instrument with both electrokinetic and hydrostatic sample injection capabilities and efficient temperature control of the separation conditions was selected on the basis of these characteristics for this project. Modifications to it included extension of the fluid circulation path in an interface block extension and electrical modifications due to changes in electrophoresis current measurement capabilities. The capabilities for complete computer automation, capillary temperature control and on-line UV detection were retained. The minimum capillary length was increased by 35 cm due to the extension to the electrospray ionization-mass spectrometer interface. Initial results employing a laboratory-designed liquid sheath electrospray source are presented which show that very high separation efficiencies can be routinely obtained using the modified instrumentation. Capabilities for combined CE-MS are demonstrated for peptide and protein mixtures. RP SMITH, RD (reprint author), PACIFIC NW LAB, DEPT CHEM SCI, CHEM METHODS & SEPARAT GRP, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 21 TC 69 Z9 69 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD OCT 18 PY 1991 VL 559 IS 1-2 BP 197 EP 208 DI 10.1016/0021-9673(91)80070-W PG 12 WC Chemistry, Analytical SC Chemistry GA GP171 UT WOS:A1991GP17100017 ER PT J AU GURLEY, LR BUCHANAN, JS LONDON, JE STAVERT, DM LEHNERT, BE AF GURLEY, LR BUCHANAN, JS LONDON, JE STAVERT, DM LEHNERT, BE TI HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS OF PROTEINS FROM THE FLUID LINING OF THE LUNGS OF RATS EXPOSED TO PERFLUOROISOBUTYLENE SO JOURNAL OF CHROMATOGRAPHY LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL SYMP ON HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS ( HPCE 91 ) CY FEB 03-06, 1991 CL SAN DIEGO, CA ID ALVEOLAR MACROPHAGES; SYSTEM AB Measurements of the biochemical constituents in the fluid lining of the lung can be used for diagnosing and assessing lung disorders. To facilitate such measurements, a high-performance capillary electrophoresis (HPCE) method has been developed by which the proteins in lung fluid can be analyzed. The lung fluid was obtained by a bronchoalveolar lavage procedure using 48 ml of physiological saline to wash out the lung fluid of rats. The proteins were precipitated from the fluid with 10 volumes of acetone and concentrated by dissolution in 2 ml of water containing 0.2% of trifluoroacetic acid. Aliquots of these samples (5-mu-l) were then injected into a Bio-Rad HPE-100 capillary electrophoresis instrument fitted with a 50 cm x 50-mu-m I.D. coated capillary filled with 0.1 M phosphate buffer (pH 2.5). With phosphate buffer in the outlet electrode chamber (cathode) and water in the inlet electrode chamber (anode), the proteins were loaded into the capillary electrophoretically for 10 s at 10 kV constant voltage. The inlet electrode chamber was then filled with phosphate buffer and HPCE was performed at 8 kV constant voltage. Six major protein fractions were resolved in 35 min, and were detected by UV absorption at 200 nm. The procedure was used to compare the lung fluid proteins of normal untreated rats with those of rats exposed by inhalation to perfluoroisobutylene (PFIB) at a concentration of 100 mg/m3. It was found that PFIB induced pulmonary edema involving a translocation of blood compartment proteins into the lung's alveolar compartment. Comparison of the HPCE fractions with similar fractions obtained by high-performance liquid chromatography confirmed albumin, transferrin and IgG as three major proteins translocated into the alveolar space after PFIB exposure. RP GURLEY, LR (reprint author), LOS ALAMOS NATL LAB,DIV LIFE SCI,MAIL STOP M880,LOS ALAMOS,NM 87545, USA. NR 22 TC 21 Z9 23 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD OCT 18 PY 1991 VL 559 IS 1-2 BP 411 EP 429 DI 10.1016/0021-9673(91)80090-4 PG 19 WC Chemistry, Analytical SC Chemistry GA GP171 UT WOS:A1991GP17100037 PM 1662223 ER PT J AU GURLEY, LR LONDON, JE VALDEZ, JG AF GURLEY, LR LONDON, JE VALDEZ, JG TI HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS OF HISTONES SO JOURNAL OF CHROMATOGRAPHY LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL SYMP ON HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS ( HPCE 91 ) CY FEB 03-06, 1991 CL SAN DIEGO, CA ID 1ST INTERNATIONAL-SYMPOSIUM; LIQUID-CHROMATOGRAPHY; HPCE 89; PHOSPHORYLATION; FRACTIONATION; SEPARATIONS; INJECTION; PROTEINS AB A high-performance capillary electrophoresis (HPCE) system was developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in 0.1 M phosphate buffer (pH 2.5) in a 35 cm x 50-mu-m I.D. coated capllary. Electrophoresis was accomplished in 9 min, separating a whole histone preparation into its components in the following order of decreasing mobility: (MHP) H3, H1 (major variant), H1 (minor variant), (LPH) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B and (MHP) H2A (minor variant), where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase high-performance liquid chromatography and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. RP GURLEY, LR (reprint author), LOS ALAMOS NATL LAB,DIV LIFE SCI,MAIL STOP M880,LOS ALAMOS,NM 87545, USA. NR 27 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD OCT 18 PY 1991 VL 559 IS 1-2 BP 431 EP 443 DI 10.1016/0021-9673(91)80091-T PG 13 WC Chemistry, Analytical SC Chemistry GA GP171 UT WOS:A1991GP17100038 PM 1761629 ER PT J AU SCHOENLEIN, RW PETEANU, LA MATHIES, RA SHANK, CV AF SCHOENLEIN, RW PETEANU, LA MATHIES, RA SHANK, CV TI THE 1ST STEP IN VISION - FEMTOSECOND ISOMERIZATION OF RHODOPSIN SO SCIENCE LA English DT Article ID PICOSECOND LASER PHOTOLYSIS; CIS-TRANS ISOMERIZATION; ABSORPTION-SPECTRA; ROOM-TEMPERATURE; BATHORHODOPSIN; DYNAMICS; PHOTORHODOPSIN AB The kinetics of the primary event in vision have been resolved with the use of femtosecond optical measurement techniques. The 11-cis retinal prosthetic group of rhodopsin is excited with a 35-femtosecond pump pulse at 500 nanometers, and the transient changes in absorption are measured between 450 and 580 nanometers with a 10-femtosecond probe pulse. Within 200 femtoseconds, an increased absorption is observed between 540 and 580 nanometers, indicating the formation of photoproduct on this time scale. These measurements demonstrate that the first step in vision, the 11-cis --> 11-trans torsional isomerization of the rhodopsin chromophore, is essentially complete in only 200 femtoseconds. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP SCHOENLEIN, RW (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Schoenlein, Robert/D-1301-2014 OI Schoenlein, Robert/0000-0002-6066-7566 FU NEI NIH HHS [T32EY07043, EY 02051] NR 25 TC 565 Z9 572 U1 13 U2 108 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD OCT 18 PY 1991 VL 254 IS 5030 BP 412 EP 415 DI 10.1126/science.1925597 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GK729 UT WOS:A1991GK72900043 PM 1925597 ER PT J AU JANSSEN, MHM PARKER, DH SITZ, GO STOLTE, S CHANDLER, DW AF JANSSEN, MHM PARKER, DH SITZ, GO STOLTE, S CHANDLER, DW TI ROTATIONAL ALIGNMENT OF THE CD3 FRAGMENT FROM THE 266-NM PHOTODISSOCIATION OF CD3I SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID MULTIPHOTON IONIZATION SPECTROSCOPY; LASER-INDUCED FLUORESCENCE; VECTOR CORRELATIONS; METHYL-IODIDE; MOLECULAR PHOTODISSOCIATION; ICN PHOTODISSOCIATION; NM PHOTODISSOCIATION; RYDBERG STATE; DIODE-LASER; CN FRAGMENT AB The alignment of CD3 fragments created by photodissociation of CD3I with linearly polarized 266-nm light is characterized by using the ion imaging technique. A linearly polarized probe laser is used for (2 + 1) resonance-enhanced multiphoton ionization (REMPI) of the methyl fragment. The three-dimensional velocity distribution of the state-selected CD3 ion is subsequently "crushed" onto a two-dimensional detector. Each position in the two-dimensional image corresponds to a different methyl fragment velocity, v. By measuring the dependence of the REMPI signal on the angle between the probe laser polarization and the photolysis laser polarization for specific parts of the image, the population n(N,K) and the alignment moments A0(2) and A0(4) of the angular momentum distribution of recoiling CD3 fragments are obtained with respect to v. These velocity-selective alignment moments describe the v.N correlation. The alignment moments extracted for single rotational levels (N,K) indicate that the rotational excitation produced in the photodissociation is about an axis perpendicular to the I-(CD3) axis and that the initial rotation about the C3 axis of the parent is conserved in the methyl fragment. The alignment moments of the fragments recoiling along the direction of the photolysis transition dipole approach the maximum values expected for a purely axial recoil process, i.e., for a methyl fragment in the N,K rotational state, \NKM(N)> = \NKK>. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94550. CATHOLIC UNIV NIJMEGEN,DEPT PHYS,6525 ED NIJMEGEN,NETHERLANDS. UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. FREE UNIV AMSTERDAM,CTR LASER,1081 HV AMSTERDAM,NETHERLANDS. NR 49 TC 71 Z9 71 U1 4 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8007 EP 8013 DI 10.1021/j100174a005 PG 7 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800008 ER PT J AU STRAUSS, CEM JIMENEZ, R HOUSTON, PL AF STRAUSS, CEM JIMENEZ, R HOUSTON, PL TI CORRELATIONS WITHOUT COINCIDENCE MEASUREMENTS - IMPACT PARAMETER DISTRIBUTIONS FOR DISSOCIATIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ANGULAR-MOMENTUM VECTORS; PHOTODISSOCIATION DYNAMICS; PHOTOFRAGMENTATION DYNAMICS; MOLECULAR PHOTODISSOCIATION; RECOIL VELOCITY; FORMALDEHYDE; SPECTROSCOPY; ENTROPY; STATE AB A method based on maximum entropy is developed in order to calculate the impact parameter distribution P(b) for dissociation of a parent compound into two fragments. The method provides the least biased P(b) distribution based on (1) whatever dynamical data are available and (2) the prior statistical information, which includes conservation of energy, linear momentum, and angular momentum. This information can often be used to decide whether a dissociation producing two fragments is concerted or stepwise. The data used to determine P(b) can include, for example, the vibrational and/or rotational distribution of the fragment(s), the recoil velocity distribution, and vector correlations. The method is illustrated by use of recent data on the photodissociation of formaldehyde. C1 CORNELL UNIV,DEPT CHEM,ITHACA,NY 14853. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 43 TC 4 Z9 4 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8110 EP 8118 DI 10.1021/j100174a020 PG 9 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800023 ER PT J AU SUITS, AG HOU, HT DAVIS, HF LEE, YT AF SUITS, AG HOU, HT DAVIS, HF LEE, YT TI DYNAMICS OF BA-BR2 CHEMIIONIZATION REACTIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ION-PAIR FORMATION; MOLECULAR-BEAM; CL2; COLLISIONS AB The formation of BaBr+ ions in reaction of Ba(1S0,1P1) with Br2 was studied as a function of laboratory scattering angle and product translational energy in a crossed-beam experiment. The contour map of BaBr+ flux obtained for the ground-state reaction at 1.1-eV collision energy showed a backscattered angular distribution (relative to the barium beam) with a substantial fraction of the available energy appearing in translation. Laser excitation strongly inhibited this channel at 1.1 eV. These experimental observations suggest that for the chemiion reaction head-on, collinear collisions and proximal crossings of the potential energy surfaces are necessary to preclude escape into the dominant neutral pathways. At 1.6-eV collision energy a new laser-dependent source of BaBr+ appeared. This laser-enhanced BaBr+ showed a laboratory angular distribution substantially narrower than for the ground-state reaction, indicating a smaller translational energy release. The angular distribution was approximately 70% backscattered and displayed a clear dip at the center of mass. This new BaBr+, produced from electronically excited barium at higher translational energy, is ascribed to secondary collisions of BaBr + Br initially formed in low impact parameter collisions. Reaction of electronically excited barium with Br2 also yielded an associative ionization product BaBr+ at both collision energies studied, with a cross section about 1/100th that of the chemiion channel. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Lee, Yuan-Tseh/F-7914-2012 NR 20 TC 6 Z9 6 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8207 EP 8211 DI 10.1021/j100174a036 PG 5 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800039 ER PT J AU YEAGER, DL MILLER, WH AF YEAGER, DL MILLER, WH TI COMPLEX LOG DERIVATIVE METHOD FOR NONREACTIVE COUPLED-CHANNEL SCATTERING CALCULATIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID KOHN VARIATIONAL PRINCIPLE; QUANTUM REACTIVE SCATTERING; S-MATRIX VERSION AB A new version of Johnson's log derivative method for integrating the (nonreactive) Schrodinger equation is described. The new feature is that the log derivative equation is integrated inward (from large r to small r) with initial conditions that correspond to asymptotically incoming (or outgoing) radial waves. The result is that the log derivative function Q(r) (which is now a complex function of r) is a very smooth, nonsingular function (compared to the oscillatory, singular behavior of Q(r) with the usual real boundary conditions), meaning that many fewer grid points are required for its numerical integration. The number of grid points necessary to achieve a given level of accuracy is also only a weak function of the scattering energy E or the mass of the particles. Test calculations for a one-dimensional and a multichannel example illustrate this behavior. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Yeager, Danny/D-3679-2015 OI Yeager, Danny/0000-0001-9832-0034 NR 8 TC 3 Z9 3 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8212 EP 8215 DI 10.1021/j100174a037 PG 4 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800040 ER PT J AU GUAN, Y MUCKERMAN, JT AF GUAN, Y MUCKERMAN, JT TI CALCULATION OF THE VIBRATIONAL LEVELS OF ELECTRONICALLY EXCITED AR-OH(A2-SIGMA+) USING A PROPOSED POTENTIAL-ENERGY SURFACE AND ANALYTIC DISCRETE VARIABLE REPRESENTATIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID OH-AR; ABINITIO CALCULATION; QUANTUM-MECHANICS; SPECTRUM; PREDISSOCIATION; DYNAMICS AB The vibrational levels of a potential energy surface recently proposed by Bowman et al. [J. Phys. Chem. 1990, 94, 2226] for the electronically excited van der Waals complex Ar-OH(A2-SIGMA+) are calculated by using analytic discrete variable representations. The results, together with those of previous calculations and with experimental spectroscopic data on vibrational band origins, are used to suggest further refinements in the potential energy function. C1 BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. RI Muckerman, James/D-8752-2013 NR 23 TC 27 Z9 27 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8293 EP 8299 DI 10.1021/j100174a051 PG 7 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800054 ER PT J AU HOFFMAN, DK NAYAR, N SHARAFEDDIN, OA KOURI, DJ AF HOFFMAN, DK NAYAR, N SHARAFEDDIN, OA KOURI, DJ TI ANALYTIC BANDED APPROXIMATION FOR THE DISCRETIZED FREE PROPAGATOR SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID WAVE-PACKET APPROACH; DEPENDENT SCHRODINGER-EQUATION; MOLECULE SURFACE SCATTERING; QUANTUM-MECHANICAL CALCULATIONS; COLLISION-INDUCED DISSOCIATION; COLLINEAR H+H2 REACTION; FOURIER METHOD SOLUTION; MONTE-CARLO METHODS; PHOTODISSOCIATION DYNAMICS; REAL-TIME AB A procedure for obtaining an approximate sparse (banded) matrix for the coordination representation of the free-particle propagator is presented. The technique takes advantage of the fact that the action of the free propagator on Hermite polynomials can be obtained analytically and represents the propagator in terms of its effect on the Hermite basis. C1 UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77204. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. NR 123 TC 134 Z9 134 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 17 PY 1991 VL 95 IS 21 BP 8299 EP 8305 DI 10.1021/j100174a052 PG 7 WC Chemistry, Physical SC Chemistry GA GL638 UT WOS:A1991GL63800055 ER PT J AU BURKARDT, M AF BURKARDT, M TI STRANGE FORM-FACTORS, THE SIGMA-TERM AND STRANGE QUARK DISTRIBUTIONS IN THE GROSS-NEVEU MODEL SO PHYSICS LETTERS B LA English DT Article ID INELASTIC ELECTRON-SCATTERING; PAIR ANNIHILATION PROCESSES; LEPTON-NUCLEON SCATTERING; SYMMETRY BREAKING; MAGNETIC-MOMENT; FIELD-THEORIES; PROTON; MATRIX AB For N(c) --> infinity the structure function of physical fermions in the Gross-Neveu model is of pure valence type. Nevertheless several strange form factors of u-quarks, including the induced magnetic moment and the sigma-term acquire substantial O(N(c)0) contributions from virtual ssBAR pairs. Those arise from matrix elements which are off-diagonal in Fock space, i.e., they do not have a simple interpretation in terms of the quark distributions. It is shown that, under certain circumstances, a similar behavior in QCD3+1 is conceivable. RP BURKARDT, M (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 20 TC 7 Z9 7 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 OCT 17 PY 1991 VL 268 IS 3-4 BP 419 EP 423 DI 10.1016/0370-2693(91)91600-Z PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GN326 UT WOS:A1991GN32600020 ER PT J AU ANDERSON, CJ DEAKIN, MR CHOPPIN, GR DOLIESLAGER, W HEERMAN, L PRUETT, DJ AF ANDERSON, CJ DEAKIN, MR CHOPPIN, GR DOLIESLAGER, W HEERMAN, L PRUETT, DJ TI SPECTROSCOPY AND ELECTROCHEMISTRY OF U(IV)/U(III) IN BASIC ALUMINUM CHLORIDE-1-ETHYL-3-METHYLIMIDAZOLIUM CHLORIDE SO INORGANIC CHEMISTRY LA English DT Article ID CHLOROALUMINATE IONIC LIQUIDS; TEMPERATURE MOLTEN-SALTS; COMPLEXES; 40-DEGREES-C; MELT; SPECTROELECTROCHEMISTRY; LANTHANIDES; URANIUM(IV); SYSTEMS AB The redox chemistry of UCl4 has been investigated in the solvent AlCl3-1-ethyl-3-methylimidazolium chloride (AlCl3-EMIC), a room-temperature ionic liquid. In basic solutions (< 50 mol % AlCl3) the reduction of U(IV) to U(III) on glassy carbon electrodes is reversible. Visible/near-IR spectroscopic data and potentiometric measurements for U(IV)/U(III) as a function of the basic composition of AlCl3-EMIC indicate U(IV) and U(III) are both hexachloro anions. Diffusion coefficients were measured for the U(IV) and U(III) complexes by two methods. The values are comparable to those of transition-metal hexachloro anionic complexes in the same solvent, supporting the assignment of [UCl6]2- and [UCl6]3-. C1 FLORIDA STATE UNIV,DEPT CHEM,TALLAHASSEE,FL 32306. OAK RIDGE NATL LAB, F68Z,OAK RIDGE,TN 37831. CATHOLIC UNIV LEUVEN,RADIOCHEM LAB,B-3030 HEVERLEE,BELGIUM. NR 25 TC 43 Z9 47 U1 3 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD OCT 16 PY 1991 VL 30 IS 21 BP 4013 EP 4016 DI 10.1021/ic00021a009 PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA GK982 UT WOS:A1991GK98200009 ER PT J AU GOUGEON, P GALL, P MCCARLEY, RE AF GOUGEON, P GALL, P MCCARLEY, RE TI STRUCTURE OF GD4MO18O32 SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID TERNARY MOLYBDENUM OXIDES; OCTAHEDRAL CLUSTER UNITS; CRYSTAL-STRUCTURE; INFINITE CHAINS; REDUCED TERNARY; COMPOUND AB M(r) = 2867.90, monoclinic, P2/c, a = 9.847 (4), b = 5.6635 (7), c = 24.116 (11) angstrom, beta = 109.74 (2)-degrees, V = 1265.9 (8) angstrom 3, Z = 2, D(x) = 7.524 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 188.71 cm-1, F(000) = 2536, T = 295 K, R = 0.035 for 2452 reflections with I > 2-sigma(I). Gd4Mo18O32 is isostructural with Ca5.45Mo18O32 and thus contains three kinds of infinite Mo chains: linear chains with alternate short and long Mo-Mo distances, chains of trans-edge-shared Mo4 rhomboidal clusters and finally chains of trans-edge-shared Mo6 octahedral clusters. While the Ca ions are delocalized in tunnels running along the b axis, the Gd ions show an order which induces a doubling of the b parameter and a changing of the space group from C2/m to P2/c. 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,UA 254,AVE GEN LECLERC,F-35042 RENNES,FRANCE. NR 30 TC 9 Z9 9 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 OCT 15 PY 1991 VL 47 BP 2026 EP 2029 DI 10.1107/S0108270191005310 PN 10 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GN421 UT WOS:A1991GN42100005 ER PT J AU BURNS, JH LUMETTA, GJ AF BURNS, JH LUMETTA, GJ TI COMPLEXES OF MANGANESE AND ZINC DI-TERT-BUTYLNAPHTHALENESULFONATE WITH CYCLOHEXANO-15-CROWN-5 ETHER TOLUENE SOLVATE SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID MACROCYCLIC POLYETHERS; EXTRACTION; 15-CROWN-5; CRYSTAL AB (1) Bis(3,7-di-tert-butylnaphthalenesulfonato)(2,5,8,11,14-pentaooxabicyclo[13.4.0]nona- decane)manganese monohydrate toluene (1/1), Mn-(C18H23O3S)2(C14H26O5).H2O.C7H8, M(r) = 1078.33, monoclinic, P2(1)/c, a = 12.737 (1), b = 39.460 (4), c = 12.765 (1) angstrom, beta = 116.40 (1)-degrees, V = 5747 (2) angstrom 3, Z = 4, D(m) = 1.24, D(x) = 1.25 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 3.47 cm-1, F(000) = 2308, T = 297 K, R(F) = 0.069 for 3060 reflections [I > 2-sigma(I)]. (2) Bis(3,7-di-tert-butylnaphthalenesulfonato)-(2,5,8,11,14-pentaoxabicyclo[13.4.0]nonadecane)zinc monohydrate toluene (1/1), Zn(C18H23O3S)2(C14H26O5).H2O.C7H8, M(r) = 1088.77, monoclinic, P2(1)/c, a = 12.766 (2), b = 39.083 (5), c = 12.771 (2) angstrom, beta = 116.44 (1)-degrees, V = 5705 (2) angstrom 3, Z = 4, D(m) = 1.28, D(x) = 1.27 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 5.69 cm-1, F(000) = 2328, T = 297 K, R(F) = 0.067 for 2240 reflections [I > 2-sigma(I)]. Complexes are isostructural. The cation is inside the crown and bonded to its five O atoms and to one O atom of a sulfonate and to one water molecule, forming a pentagonal bipyramid coordination. The second sulfonate ion is hydrogen bonded to the water. There is disorder affecting a tert-butyl group and possibly the toluene solvate. RP BURNS, JH (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 16 TC 8 Z9 8 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 OCT 15 PY 1991 VL 47 BP 2069 EP 2073 DI 10.1107/S0108270191003797 PN 10 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GN421 UT WOS:A1991GN42100019 ER PT J AU HENDRIXSON, TL TERHORST, MA JACOBSON, RA AF HENDRIXSON, TL TERHORST, MA JACOBSON, RA TI STRUCTURE OF DIPYRIDINIUM DECAIODIDE - AN INFINITE CHAIN STRUCTURE SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article AB 2C5H6N+.I102-, M(r) = 1429.26, orthorhombic, Pmc2(1), a = 17.331 (4), b = 4.5336 (7), c = 17.615 (3) angstrom, V = 1384.0 (4) angstrom 3, Z = 2, D(x) = 3.42 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 110.8 cm-1, F(000) = 1232, T = 273 K, final R = 0.048 for 555 unique reflections with \F-omicron\ greater-than-or-equal-to 3-sigma(\F-omicron\). The I atoms form two distinct moieties, an I7- and an I3-. The I7- ions form interconnected sheets which are parallel to the ab plane. The I3- ions form an infinite chain which propagates along the c direction. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 13 TC 17 Z9 17 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 OCT 15 PY 1991 VL 47 BP 2141 EP 2144 DI 10.1107/S0108270191003839 PN 10 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GN421 UT WOS:A1991GN42100043 ER PT J AU ELFALLAH, MZ GUIOCHON, G AF ELFALLAH, MZ GUIOCHON, G TI GRADIENT ELUTION CHROMATOGRAPHY AT VERY HIGH COLUMN LOADING - EFFECT OF THE DEVIATION FROM THE LANGMUIR MODEL ON THE BAND PROFILE OF A SINGLE COMPONENT SO ANALYTICAL CHEMISTRY LA English DT Article ID NONLINEAR LIQUID-CHROMATOGRAPHY; MOBILE PHASE; IDEAL MODEL; SEPARATION; PROPAGATION; SIMULATION; EQUATION; BINARY AB The elution profiles of very large samples of 2-phenylethanol obtained with steep concentration gradients are compared with those predicted by theory. The main difficulties encountered in this modeling stem from the needs of an accurate determination of the adsorption data at high concentrations, an accurate modeling of these data and the determination of the exact injection profile. In gradient elution the high-concentration part of the isotherm influences the band profiles more than in isocratic chromatography. The importance of an accurate equilibrium isotherm is much higher for the accurate simulation of profiles obtained in gradient elution than for those provided by isocratic elution, because in the latter case, the bands dilute steadily during their migration while in the former case they concentrate. Similarly, samples injected in gradient elution have typically a much larger volume and are more dilute. Unusual profiles are predicted and observed in agreement with these predictions, when the sample amount is of the order of the column saturation capacity and/or the sample volume is of the order of the retention volume at the mobile phase composition of the gradient start. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DEPT ANALYT CHEM,OAK RIDGE,TN 37831. NR 21 TC 27 Z9 27 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 15 PY 1991 VL 63 IS 20 BP 2244 EP 2252 DI 10.1021/ac00020a010 PG 9 WC Chemistry, Analytical SC Chemistry GA GJ962 UT WOS:A1991GJ96200010 ER PT J AU MARTIN, SJ GRANSTAFF, VE FRYE, GC AF MARTIN, SJ GRANSTAFF, VE FRYE, GC TI CHARACTERIZATION OF A QUARTZ CRYSTAL MICROBALANCE WITH SIMULTANEOUS MASS AND LIQUID LOADING SO ANALYTICAL CHEMISTRY LA English DT Article ID PIEZOELECTRIC-CRYSTALS; RESONATORS; ELECTRODES; MECHANISM; FREQUENCY; CONTACT; SENSORS; MODE AB With a continuum electromechanical model, the electrical admittance has been derived for an AT-cut quartz crystal microbalance (QCM) simultaneously loaded by a surface mass layer and a contacting Newtonian liquid. This admittance expression is used to derive a lumped-element equivalent circuit model that describes the near-resonance electrical characteristics of the QCM under these loading conditions. The resulting model is a modified Butterworth-Van Dyke equivalent circuit, having circuit elements that are explicitly related to physical properties of the quartz, perturbing mass layer, and contacting liquid. The effects of mass and liquid loading on the fundamental and third harmonic resonances are predicted from the model and compared with experimental impedance analyzer measurements. Surface mass accumulation causes a simple translation in frequency of the resonance peak, while increasing the density-viscosity product of the contacting solution causes both a translation and a damping of the resonance peak. With the model, changes in surface mass can be differentiated from changes in solution properties. RP MARTIN, SJ (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 34 TC 732 Z9 755 U1 20 U2 127 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 15 PY 1991 VL 63 IS 20 BP 2272 EP 2281 DI 10.1021/ac00020a015 PG 10 WC Chemistry, Analytical SC Chemistry GA GJ962 UT WOS:A1991GJ96200015 ER PT J AU ADHIHETTY, IS MCGUIRE, JA WANGMANEERAT, B NIEMCZYK, TM HAALAND, DM AF ADHIHETTY, IS MCGUIRE, JA WANGMANEERAT, B NIEMCZYK, TM HAALAND, DM TI ACHIEVING TRANSFERABLE MULTIVARIATE SPECTRAL CALIBRATION MODELS - DEMONSTRATION WITH INFRARED-SPECTRA OF THIN-FILM DIELECTRICS ON SILICON SO ANALYTICAL CHEMISTRY LA English DT Article ID SQUARES QUANTITATIVE-ANALYSIS; FT-IR SPECTRA; BOROPHOSPHOSILICATE GLASSES; SPECTROSCOPIC DATA; REFLECTANCE AB Multivariate calibration methods are very useful in improving the precision, accuracy, and reliability of quantitative spectral analyses. In this study, the transfer of partial least-squares (PLS) calibration models between spectrometers was investigated for the quantitative infrared analysis of borophosphosilicate glass (BPSG) thin films on silicon wafers. In the determination of phosphorus, boron, and thickness for BPSG films, sensitivity studies showed that detector nonlinearity, frequency accuracy, incident angle, and variations in purge were important parameters to control to obtain transferable calibrations. The difficulty in achieving a transferable calibration model was found to increase as the complexity of the calibration model increased. A combination of controlling sensitive experimental parameters, selecting appropriate frequencies, and subtracting the spectra of purge gases improved the standard error of prediction for phosphorus determination from 0.75 to 0.18 wt % when predicting on spectra collected on a spectrometer different from that upon which the calibration model was based. This improvement in prediction ability resulted in a PLS calibration model that was transferable between two spectrometers. It has been shown that sensitive outlier detection methods can be used to identify model transfer problems. The ability to achieve calibration models that are robust to spectrometer variations implies that these calibrations can also be robust to spectrometer drift. C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,LIVERMORE,CA 94550. NR 26 TC 35 Z9 35 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 15 PY 1991 VL 63 IS 20 BP 2329 EP 2338 DI 10.1021/ac00020a024 PG 10 WC Chemistry, Analytical SC Chemistry GA GJ962 UT WOS:A1991GJ96200024 ER PT J AU MORRIS, SW VALENTINE, MB SHAPIRO, DN SUBLETT, JE DEAVEN, LL FOUST, JT ROBERTS, WM CERRETTI, DP LOOK, AT AF MORRIS, SW VALENTINE, MB SHAPIRO, DN SUBLETT, JE DEAVEN, LL FOUST, JT ROBERTS, WM CERRETTI, DP LOOK, AT TI REASSIGNMENT OF THE HUMAN CSF1 GENE TO CHROMOSOME 1P13-P21 SO BLOOD LA English DT Article ID COLONY-STIMULATING FACTOR; C-FMS; INSITU HYBRIDIZATION; MOLECULAR-CLONING; MYELOID DISORDERS; REGULATING HEMATOPOIESIS; PLACENTAL DEVELOPMENT; PROTO-ONCOGENE; DELETION 5Q; GM-CSF C1 ST JUDE CHILDRENS RES HOSP, DEPT HEMATOL ONCOL, 332 N LAUDERDALE, MEMPHIS, TN 38105 USA. IMMUNEX CORP, DEPT MOLEC BIOL, SEATTLE, WA USA. ST JUDE CHILDRENS RES HOSP, DEPT TUMOR CELL BIOL, MEMPHIS, TN 38101 USA. UNIV TENNESSEE, CTR HLTH SCI, COLL MED, DEPT PEDIAT, MEMPHIS, TN 38163 USA. UNIV CALIF LOS ALAMOS SCI LAB, EXPTL PATHOL GRP, LOS ALAMOS, NM 87545 USA. FU NCI NIH HHS [CA-20180, CA-21765, CA-23099] NR 37 TC 47 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 OCT 15 PY 1991 VL 78 IS 8 BP 2013 EP 2020 PG 8 WC Hematology SC Hematology GA GK542 UT WOS:A1991GK54200017 PM 1912583 ER PT J AU DELMORE, JE APPELHANS, AD PETERSON, ES AF DELMORE, JE APPELHANS, AD PETERSON, ES TI TUBE ION-SOURCE FOR THE STUDY OF CHEMICAL EFFECTS IN SURFACE-IONIZATION SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article ID MASS-SPECTROMETRY AB An ion source has been developed in which gas phase ions are sublimed from bulk powders contained in a refractory metal tube. The outside of the tube is heated by electron impact, and the ions are emitted from an opening in the end of the tube. Regulation of the electron emission current makes it possible to maintain a constant source temperature from 700 to 2200 K. The design easily accommodates a wide range of powders/blends making it possible to study bulk chemistry effects on the formation of atomic and molecular ions and easily survey a wide range of materials under well controlled temperature conditions. Examples are given of gas phase perrhenate anion production which show that ion production from these bulk powders is controlled by the same chemical and physical mechanisms as thin-layer systems on heated filaments. RP DELMORE, JE (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. RI Peterson, Eric/B-9127-2017 OI Peterson, Eric/0000-0002-2292-4939 NR 8 TC 29 Z9 29 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD OCT 15 PY 1991 VL 108 IS 2-3 BP 179 EP 187 DI 10.1016/0168-1176(91)85032-H PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA GN086 UT WOS:A1991GN08600005 ER PT J AU ADAMS, RG DILLON, MM AF ADAMS, RG DILLON, MM TI NARROW LINEWIDTH GAIN MEASUREMENTS IN KRF AND ARF EXCIMER AMPLIFIERS PUMPED LONGITUDINALLY BY HIGH-POWER ELECTRONS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTENSITY; BEAM AB Single-pulse KrF and ArF gain measurements have been conducted with an excimer amplifier longitudinally pumped by a high-power (approximately 5-MW/cm3 deposition) electron beam. This amplifier has preserved the narrow linewidth (approximately 10 GHz) exhibited by the probe laser beam generated by a grating-tuned, discharge pumped excimer laser. Single-pass gain was measured at 248.45 nm, the peak of the KrF laser gain profile, for a laser pulse with full width half maximum (FWHM) of 20 ns. Analysis of the gain data by a modified Rigrod steady-state formulation yielded values for the small-signal gain, the nonsaturable absorption, and saturation intensity of g0 = 12.6%/cm, alpha approximately 0.45%/cm, and I(s) = 4.1 MW/cm2, respectively, for a 750-Torr laser mix. The corresponding gain peak measurement for an ArF beam at 193.31 nm with FWHM of 15 ns produced g0 = 12.1%/cm, alpha approximately 0.70%/cm, and I(s) = 6.7 MW/cm2 for a 963-Torr laser mix with the same stopping power as the KrF mix. Measurement of gain at 193.68 nm, well away from gain peak, resulted in g0 = 10.8%/cm, alpha approximately 0.70%/cm, and I(s) = 7.9 MW/cm2 for the same ArF mixture. Several amplified spontaneous emission and oscillator measurements have also been performed. Indications of laser gain saturation at high-power electron-beam deposition have been deduced. RP ADAMS, RG (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 22 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4073 EP 4081 DI 10.1063/1.349157 PG 9 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300011 ER PT J AU TONKS, DL AF TONKS, DL TI PLASTICITY PATH EFFECTS IN METALS UNDER SHOCK COMPRESSION SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SOLIDS; FLOW AB When plasticity data from weak shocks are plotted in the form of plastic strain rate versus deviatoric stress, the resulting curve exhibits a loop for several metals. Using the single-state- variable theory of E. W. Hart [Acta Metall. 18, 599 (1970)], this loop is interpreted to mean more than one state variable is necessary to explain the shock-wave plasticity for these metals. This circumstance could be due to a change in the mechanism of plastic flow to dislocation drag. Other explanations are possible, however. RP TONKS, DL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4233 EP 4237 DI 10.1063/1.349149 PG 5 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300031 ER PT J AU TONKS, DL AF TONKS, DL TI MODEL FOR THE RELATION BETWEEN SHOCK VELOCITY AND PARTICLE-VELOCITY IN WEAK SHOCK-WAVES IN METALS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PRESSURE-DEPENDENCE; ELASTIC-CONSTANTS; MODULUS; SOLIDS; COPPER; FLOW AB The weak-shock theory of D. C. Wallace [Phys. Rev. B 22, 1487 (1980)] is used to calculate shock velocities as a function of particle velocity. The calculated shock velocities are based on thermoelastic behavior, plasticity behavior, and precursor behavior. The results are calculated and compared with data for 6061T6 Al, Be, Cu, Fe, 21-6-9 stainless steel, and U. Except for Fe, the agreement is reasonable. The contributions to the shock velocity from material strength and precursor behavior are rather small but, nevertheless, are calculated fairly well with the present theory. RP TONKS, DL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 38 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4238 EP 4247 DI 10.1063/1.349150 PG 10 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300032 ER PT J AU RICHARDS, PM AF RICHARDS, PM TI SPATIAL PROFILES OF TRAPPED HYDROGEN OR CENTERS EXCITED BY HYDROGEN DIFFUSION SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SILICON; DEUTERIUM; MODEL AB Nearly step-function-like profiles of trapped hydrogen or of properties, such as donor concentration, related to hydrogen diffusion are often observed in semiconductors. Expressions are derived for the depth of such profiles and their finite width as a function of time for arbitrary ratios of hydrogen concentration to trap concentration and for nonzero detrapping rates. The depth scales as t1/2 for normal trapping, but as (t ln t)1/2 if the observed quantity is excited by hydrogen passing in the vicinity without being trapped. The width of the profile is time-dependent if hydrogen traps irreversibly. For reversible trapping or excitation without trapping the width is proportional to t1/2 or (t ln t)1/2, respectively. RP RICHARDS, PM (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 14 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 OCT 15 PY 1991 VL 70 IS 8 BP 4255 EP 4262 DI 10.1063/1.349129 PG 8 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300034 ER PT J AU PAINE, DC EVANS, ND STOFFEL, NG AF PAINE, DC EVANS, ND STOFFEL, NG TI A STUDY OF THE EFFECT OF MISFIT-INDUCED STRAIN ON THE KINETICS OF SOLID-PHASE EPITAXY IN THE SI1-XGEX ON (001) SI SYSTEM SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RESOLUTION ELECTRON-MICROSCOPY; REGROWTH RATE; ELASTIC RELAXATION; AMORPHOUS SI; LAYERS; SUBSTRATE; GROWTH AB In this paper we present the results of an experimental determination of the rate of solid phase epitaxical regrowth of amorphous Si1-xGex on <001> Si as a function of temperature and Ge concentration. Layers of chemical vapor deposited Si1-xGex roughly 200-nm thick containing 5.4, 11.6, and 17.0 at. % Ge were amorphized with a two-step process of 100 keV, followed by 200 keV, Si-29 ion implantation. This procedure left the near surface region of the substrate, including the entire Si1-xGex film, amorphous to a depth of 380 nm. The epitaxical recrystallization of the alloy portion (5.4, 11.6, or 17 at. % Ge) of the amorphous layer results in the development of large lattice mismatch stresses (0.5-2 GPa). The rate of epitaxical regrowth of the amorphous material was studied with isothermal heating and in situ transmission electron microscopy observations. Isothermal annealing at temperatures between 476 and 602-degrees-C show that, compared to pure unstrained Si, the rate of regrowth is decreased in strained alloys of Si1-xGex. Furthermore, we report that the activation energy for strained-layer regrowth of Si1-xGex is not a strong function of composition and, for all three compositions, was in the range 3.2 +/- 0.2 eV. This is significantly larger than the activation energy for the homoepitaxical regrowth of unstrained pure Si. Stress related origins of these observations are discussed. C1 OAK RIDGE ASSOCIATED UNIV,OAK RIDGE NATL,OAK RIDGE,TN 37831. BELLCORE,RED BANK,NJ 07701. RP PAINE, DC (reprint author), BROWN UNIV,DIV ENGN,BOX D,PROVIDENCE,RI 02912, USA. RI Evans, Neal/F-5955-2011 NR 22 TC 44 Z9 44 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 OCT 15 PY 1991 VL 70 IS 8 BP 4278 EP 4286 DI 10.1063/1.349105 PG 9 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300037 ER PT J AU LI, Q OSTENSON, JE FINNEMORE, DK AF LI, Q OSTENSON, JE FINNEMORE, DK TI STRAIN TOLERANCE OF BI2SR2CA1CU2O8-DELTA/AG COMPOSITES AT HIGH-FIELD SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Strain tolerance of Bi2Sr2Ca1Cu2O8-delta/Ag composites have been studied at fields up to 20 T and bending strains up to 2.6% in order to determine the factors that control the critical current density. The goal is to find the best way to distribute Ag such as to give both high strain tolerance and high critical current density. Partial melt processed samples prepared from micromilled mixtures containing 30% Ag by volume show a gradually decreasing critical current all the way out to 2.6% strain. Samples typically show about 1000 A/cm2 at 4.2 K, 20 T, and 0.75% strain. At 20 K, these values occur at 4 T and 0.75% strain. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP LI, Q (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 6 TC 20 Z9 20 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4392 EP 4397 DI 10.1063/1.349121 PG 6 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300054 ER PT J AU MULLER, H SUENAGA, M YOKOYAMA, Y AF MULLER, H SUENAGA, M YOKOYAMA, Y TI MAGNETOOPTIC IMAGES OF FLUX DISTRIBUTION AND CREEP IN YBA2CU3O7 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SUPERCONDUCTORS; STATE AB A magneto-optic imaging technique was used to examine the flux distributions at 50, 60, and 70 K in a single-crystal platelet of YBa2Cu3O7. The superconducting sample was covered with a layer of iron garnet film, and a polarization microscope was used to examine the magnetic domains in this imaging film. Since the spacing of these domains was proportional to the local magnetic field in the underlying superconductor, it was possible to determine field profiles directly from the optical density of the image. Field profiles indicated that the distributions of remnant flux in the sample were well described by the critical state model. It was also possible, through the use of simple linear models of initial flux penetration, to measure the flux trapped in the sample as a function of time. The flux creep data derived from analysis of the digitized images showed a logarithmic decrease of magnetization with time, in good agreement with SQUID magnetometer measurements performed on the sample. There was no evidence of an axial critical state. C1 ELECTROTECH LAB,TSUKUBA,IBARAKI 305,JAPAN. RP MULLER, H (reprint author), BROOKHAVEN NATL LAB,DIV MAT SCI,UPTON,NY 11973, USA. NR 12 TC 8 Z9 8 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 OCT 15 PY 1991 VL 70 IS 8 BP 4409 EP 4414 DI 10.1063/1.349123 PG 6 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300056 ER PT J AU MAHAN, GD AF MAHAN, GD TI INHOMOGENEOUS THERMOELECTRICS SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Theoretical calculations show that inhomogeneous doping can increase the efficiency of thermoelectric generators and refrigerators. 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 14 TC 76 Z9 76 U1 1 U2 18 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4551 EP 4554 DI 10.1063/1.349091 PG 4 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300079 ER PT J AU MILLER, SL MCWHORTER, PJ MILLER, WM DRESSENDORFER, PV AF MILLER, SL MCWHORTER, PJ MILLER, WM DRESSENDORFER, PV TI A PRACTICAL PREDICTIVE FORMALISM TO DESCRIBE GENERALIZED ACTIVATED PHYSICAL PROCESSES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THERMALLY STIMULATED CURRENTS; ARBITRARY TRAP DISTRIBUTIONS; DIELECTRIC-RELAXATION; ISOTHERMAL CURRENTS; MEMORY TRANSISTORS; INSULATORS; SEMICONDUCTORS; ENVIRONMENT; PARAMETERS; DISCHARGE AB A predictive formalism is developed that is applicable to the large class of activated physical systems described by a differential equation of the generic form: partial derivative n(phi,t)/partial derivative t = - n(phi,t)F(t) exp(- (phi - R(t))/A(t)). Practical techniques to predict the behavior of activated physical systems for arbitrary time-dependent environments are both intuitively and mathematically developed. Useful techniques to experimentally determine the initial distribution of activation energies, utilizing arbitrary time-dependent laboratory environments, are presented. A number of fundamental results regarding the correct use and interpretation of common diagnostic techniques, such as Arrhenius plots, are derived. It is shown how the predictive results significantly enhance the ability to quantitatively evaluate the reliability of physical systems whose rate-limiting mechanisms are activated processes obeying the above differential equation. Specific issues regarding integrated circuit reliability are examined as potential applications of this predictive formalism, including time-dependent dielectric breakdown, metal electromigration, nonvolatile memory retention, annealing of radiation-induced trapped charge, and thin ferroelectric film switching properties. RP MILLER, SL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 34 TC 22 Z9 22 U1 1 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 OCT 15 PY 1991 VL 70 IS 8 BP 4555 EP 4568 DI 10.1063/1.349092 PG 14 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300080 ER PT J AU MILLER, SL MCWHORTER, PJ AF MILLER, SL MCWHORTER, PJ TI A PREDICTIVE MODEL OF ELECTRON AND HOLE DECAY IN SILICON-NITRIDE-OXIDE-SILICON NONVOLATILE MEMORY TRANSISTORS EXPERIENCING ARBITRARY THERMAL ENVIRONMENTS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RETENTION; EEPROM AB A model is presented which accurately predicts the threshold voltage decay of both the excess electron and excess hole logic states of silicon-nitride-oxide-silicon nonvolatile memory transistors in thermally varying environments. The model predictions require as inputs the initial occupied trap distributions for both trapped holes and trapped electrons. A technique is presented to determine all model parameters, including the initial occupied trap distributions, by performing a single practical experiment with a specific thermal scenario. Once the model parameters are determined by this single experiment, the threshold voltage is predicted (with no adjustable parameters) for arbitrary time dependent thermal environments. Retention experiments are performed for a wide range of thermal environments which are changed during the charge decay process. The accuracy of the model predictions is verified by experimental data. RP MILLER, SL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87111, USA. NR 14 TC 11 Z9 11 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4569 EP 4576 DI 10.1063/1.350341 PG 8 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300081 ER PT J AU CARAMANA, EJ WEBSTER, RB QUIGLEY, GP MORSE, RL AF CARAMANA, EJ WEBSTER, RB QUIGLEY, GP MORSE, RL TI THEORETICAL AND EXPERIMENTAL STUDIES OF CO2-LASER EVAPORATION OF CLOUDS SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB A study of the effects of laser radiation on cloud drops and of the possibility of producing a clear optical channel in a cloud is presented. In order to produce a model that is appropriate to a realistic cloud with a distribution of drop sizes it is first necessary to study what happens to a single water drop subjected to laser radiation of different intensities. Various heating regimes are mapped out as a function of laser flux and fluence at the 10.6-mu-m wavelength. It is found that typical cloud drops can superheat until they become unstable and explode from the center. For a long laser pulse the boundary for this to occur is found to be 50(5/r)2 kW/cm2, where r is the drop radius in microns. Using these results a model that is spatially one-dimensional through the cloud is constructed for a distribution of drop sizes. Laser beam intensity as the light penetrates a cloud is calculated from Mie scattering and absorption cross sections for a beam diameter that is small in the sense that light scattered once is assumed lost. The internal temperature distribution of the drops is calculated and a phenomenological drop explosion model is given for drops that reach the unstable 305-degrees-C spinodal temperature at their center. Energy and water mass content are conserved as the cloud background is modified in an average sense by drop evaporation or recondensation. Recondensation is treated in the diffusion regime according to the Kohler model, with vapor pressure over a drop modified by surface tension and dissolved nonwater content. Comparison with experimental data for a laboratory produced cloud is given and good agreement, particularly with respect to the predicted onset of drop explosion, is found. Results are also presented for hypothetical cloud conditions and laser intensities. The possibility of clearing a thin cloud with low fluence to the 3.8-mu-m is considered, as well as the passive evaporation of melted ice crystal clouds. RP CARAMANA, EJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 19 TC 2 Z9 2 U1 1 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 OCT 15 PY 1991 VL 70 IS 8 BP 4601 EP 4616 DI 10.1063/1.349097 PG 16 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300086 ER PT J AU CHEN, CH PHILLIPS, RC AF CHEN, CH PHILLIPS, RC TI DESORPTION SPECTRA OF LASER ABLATION OF BI2SR2CACU2O8+X SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID SUPERCONDUCTING THIN-FILMS; SR-CU-O; DEPOSITION; SYSTEM; EVAPORATION; INSITU AB Quantitative measurements of desorbed ions and neutral molecules by a mass spectrometer from laser ablation of Bi2Sr2CaCu2O8+x were obtained. The results indicate that more neutral atoms and molecules desorbed than the corresponding ions. The ratio of neutral atoms to ions decreases when the laser power density increases. RP CHEN, CH (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,CHEM PHYS SECT,OAK RIDGE,TN 37831, USA. NR 27 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 15 PY 1991 VL 70 IS 8 BP 4643 EP 4645 DI 10.1063/1.349054 PG 3 WC Physics, Applied SC Physics GA GL023 UT WOS:A1991GL02300096 ER PT J AU NORWOOD, K NG, CY AF NORWOOD, K NG, CY TI OBSERVATION OF AUTOIONIZING RYDBERG SERIES CONVERGING TO SO3+(2E',2A1') SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOION PHOTOELECTRON COINCIDENCE; S2O AB The ionization energy of SO3 is determined to be 12.828 +/- 0.010 eV from photoionization mass spectrometric measurements of SO3. Two autoionization Rydberg series converging to the SO3 (2E') state (17.901 eV) are identified. Three window resonances observed in the region 610-690 angstrom are assigned as members of an autoionizing Rydberg series converging to the SO3+(2A'1) state (20.603 eV). C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP NORWOOD, K (reprint author), US DOE,AMES LAB,AMES,IA 50011, 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1991 VL 95 IS 8 BP 5553 EP 5555 DI 10.1063/1.461628 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200006 ER PT J AU TONKYN, RG WHITE, MG AF TONKYN, RG WHITE, MG TI VIBRATIONAL SPECTROSCOPY OF XE2+ VIA PULSED FIELD-IONIZATION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENHANCED MULTIPHOTON IONIZATION; VANDERWAALS MOLECULE; PHOTOELECTRON-SPECTRUM; ABSORPTION-SPECTRUM; ELECTRONIC STATES; PHOTO-IONIZATION; XE-2; PHOTOIONIZATION; THRESHOLD; CURVES AB Delayed, pulsed field ionization of extremely high-n Rydberg states has been used in combination with a high-resolution vacuum ultraviolet radiation source to measure the vibrationally resolved spectra of the first three bound states of Xe2+. For the ground state of the ion (A 2-SIGMA-u+), a long progression beginning at upsilon+ = 56 was observed which included isotopically resolved energy levels. The spectroscopic parameters obtained from a fit of the data to anharmonic oscillator energy levels are reported. The resulting Xe2 ionization potential is somewhat higher than previously reported. Several vibrations of the first excited state (B 2-PI(3/2)g) were observed near 97 000 cm-1. An absolute vibrational assignment was not possible due to an unusual alternation of intensities. Nevertheless, a lower bound on the binding energy and an estimated vibrational frequency are reported. For the C 2-PI(3/2)u state, the upsilon+ = 0-2 vibrational levels were observed with an intensity distribution consistent with the weakly bound nature of this state. The derived binding energy and vibrational frequency for the C 2-PI(3/2)u state are reported. RP TONKYN, RG (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 24 TC 45 Z9 45 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1991 VL 95 IS 8 BP 5582 EP 5589 DI 10.1063/1.461632 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200010 ER PT J AU MOORE, DS SCHMIDT, SC SHAW, MS JOHNSON, JD AF MOORE, DS SCHMIDT, SC SHAW, MS JOHNSON, JD TI COHERENT ANTI-STOKES-RAMAN SPECTROSCOPY OF SHOCK-COMPRESSED LIQUID CARBON-MONOXIDE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 900 KBAR; NITROGEN; SCATTERING; MIXTURES; OXYGEN; CARS; TEMPERATURE; DEPENDENCE; DENSITY; GPA AB Vibrational spectra of liquid carbon monoxide shock compressed to several high pressure/high temperature states were recorded using single-pulse multiplex coherent anti-Stokes Raman scattering. Vibrational frequencies, third-order susceptibility ratios, and linewidths are reported for the fundamental and first excited-state transition. The observed vibrational frequency shift with shock pressure was substantially less than that observed previously in nitrogen, implying a significant difference in the details of their inter- and intramolecular potentials. The transition intensity and linewidth data suggest that thermal equilibrium of the vibrational levels is attained in less than 10 ns at these shock pressures, and the vibrational temperatures obtained are comparable to calculated equation-of-state temperatures. The measured linewidths suggest that the vibrational dephasing time decreased to approximately 2 ps at our highest pressure shock state. RP MOORE, DS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Moore, David/C-8692-2013 NR 32 TC 12 Z9 12 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1991 VL 95 IS 8 BP 5603 EP 5608 DI 10.1063/1.461634 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200012 ER PT J AU VALLEAU, JP DIESTLER, DJ CUSHMAN, JH SCHOEN, M HERTZNER, AW RILEY, ME AF VALLEAU, JP DIESTLER, DJ CUSHMAN, JH SCHOEN, M HERTZNER, AW RILEY, ME TI ADSORPTION AND DIFFUSION AT ROUGH SURFACES - A COMPARISON OF STATISTICAL-MECHANICS, MOLECULAR-DYNAMICS, AND KINETIC-THEORY - COMMENT SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter ID SIMPLE CLASSICAL FLUID; SLIT-PORE; MICROPORES C1 PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. PURDUE UNIV,DEPT AGRON,W LAFAYETTE,IN 47907. UNIV WITTEN HERDECKE,FAK NAT WISSENSCH,INST EXPTL PHYS,W-5810 WITTEN,GERMANY. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP VALLEAU, JP (reprint author), UNIV TORONTO,DEPT CHEM,TORONTO M5S 1A1,ONTARIO,CANADA. NR 8 TC 10 Z9 10 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 15 PY 1991 VL 95 IS 8 BP 6194 EP 6195 DI 10.1063/1.461595 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GJ592 UT WOS:A1991GJ59200075 ER PT J AU MINNETT, PJ AF MINNETT, PJ TI CONSEQUENCES OF SEA-SURFACE TEMPERATURE VARIABILITY ON THE VALIDATION AND APPLICATIONS OF SATELLITE MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID HIGH-RESOLUTION RADIOMETER; NORTH-ATLANTIC; INFRARED MEASUREMENTS; CHANNELS; MODEL; OCEAN; SPACE; FRONT AB Sea surface temperature (SST) measurements from both spaceborne and in situ sensors are analyzed to determine likely temperature differences that can arise between two measurements separated in space and time. This has implications both for satellite data validation, where an in situ measurement is compared with a remotely sensed one, and for the use of SST measurements in numerical upper ocean models, where an SST value is ascribed to or compared with one from a nearby grid point at the closest time step. It is shown that spatial separations of about 10 km and time intervals of about 2 hours can introduce rms differences of 0.2 K into the error budget of a satellite validation data set, this being an upper limit for the meaningful validation of current infrared radiometers. The length and time scales at which the autocorrelation functions decay to 0.5 is used as a criterion for the meaningful use of SST data with ocean models, and these are found to be about 10-20 km and about 6 hours. This time constraint is not very severe, but the spatial constraint poses a significant sampling problem. On these length scales there appears to be no spatial anisotropy with respect to the dominant surface current flow direction. RP MINNETT, PJ (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV OCEANOG & ATMOSPHER SCI,BLDG 318,UPTON,NY 11973, USA. NR 51 TC 53 Z9 53 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD OCT 15 PY 1991 VL 96 IS C10 BP 18475 EP 18489 DI 10.1029/91JC01816 PG 15 WC Oceanography SC Oceanography GA GL027 UT WOS:A1991GL02700010 ER PT J AU HSUEH, CH AF HSUEH, CH TI INTERFACIAL DEBONDING AND FIBER PULL-OUT STRESSES OF FIBER-REINFORCED COMPOSITES .3. WITH RESIDUAL RADIAL AND AXIAL STRESSES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID BOND STRENGTH; MATRIX AB A fiber-reinforced elastic composite with residual radial and axial stresses is considered. The effects of the residual stresses on the fiber pull-out process are studied. The shear lag model is used for stress analyses, and the interfacial shear strength is adopted as the debonding criterion. The results show that for a bonded interface the applied axial stress on the fiber required to debond the interface depends strongly on the residual axial stress but is not sensitive to the residual radial stress. When the interface is partially debonded during fiber pull-out, the residual axial stress is relaxed in the debonded region. However, the residual axial stress in the bonded region influences the stress required for partial debonding by modifying the stress at the end of debonding. RP HSUEH, CH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 12 TC 36 Z9 36 U1 2 U2 6 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD OCT 15 PY 1991 VL 145 IS 2 BP 135 EP 142 DI 10.1016/0921-5093(91)90242-F PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA GP102 UT WOS:A1991GP10200001 ER PT J AU HSUEH, CH AF HSUEH, CH TI INTERFACIAL DEBONDING AND FIBER PULL-OUT STRESSES OF FIBER-REINFORCED COMPOSITES .4. SLIDING DUE TO RESIDUAL-STRESSES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID STRENGTH; MATRIX AB A fiber-reinforced elastic composite subjected to residual radial (compressive) and axial stresses, induced by mismatch strains between the fiber and the matrix, is considered. For an unbonded or a weak interface, sliding at the fiber-matrix interface can occur due to residual stresses. The sliding length and the stress distribution in the composite are analyzed in the present study. The results show that the sliding length is limited by the interfacial friction. The fiber can pop out of or sink beneath the surface of the composite depending mainly on the mismatch strain in the axial direction. However, the sliding phenomena are modified by the mismatch strain in the radial direction because of Poisson's effect. RP HSUEH, CH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 10 TC 17 Z9 17 U1 2 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD OCT 15 PY 1991 VL 145 IS 2 BP 143 EP 150 DI 10.1016/0921-5093(91)90243-G PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA GP102 UT WOS:A1991GP10200002 ER PT J AU SPITZIG, WA TRYBUS, CL LAABS, FC AF SPITZIG, WA TRYBUS, CL LAABS, FC TI STRUCTURE PROPERTIES OF HEAVILY COLD-DRAWN NIOBIUM SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID COMPOSITES; STRENGTH AB The mechanical properties and microstructural evolution were evaluated for wires of niobium, cold drawn to true strains eta-up to 11.9. The ultimate tensile stress and fracture stress of niobium increases exponentially after drawing to eta = 8.9. At larger true strains, up to eta = 11.9 saturation hardening is observed in niobium as it is at much lower deformation strains (eta > 5.3) in copper. Niobium remains ductile after deformation processing to true strains up to eta = 11.9, but at eta greater-than-or-equal-to 10.3, failure occurs by ductile shear. Previous studies on heavily deformation-processed b.c.c. metals usually have been restricted to eta < 8.9, which is the most likely reason why saturation hardening was not previously observed in b.c.c. metals (J. Gil Sevillano et al., Progr. Mater., Sci., 25 (1981) 69; J. Gil Sevillano, Acta Metall., 34 (1986) 1473). Comparison of hardening in identically wire-drawn niobium and copper shows that the predominant difference between them was that copper exhibited saturation hardening after smaller draw ratios. Hardening in both metals appeared to be exponential in nature prior to the onset of saturation hardening. Analyses of the substructural development in niobium with increasing degree of deformation processing by wire drawing showed that grains and cells on transverse sections start with equiaxed shapes becoming ribbon-like and curled about the wire axis, tending toward a more equiaxed shape again with increasing deformation processing. The dislocation structures observed for niobium are typical of those observed in stage IV hardening and the substructural development with increasing deformation processing appears similar to previously reported observations on other b.c.c. metals. RP SPITZIG, WA (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 19 TC 18 Z9 18 U1 1 U2 6 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD OCT 15 PY 1991 VL 145 IS 2 BP 179 EP 187 DI 10.1016/0921-5093(91)90247-K PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA GP102 UT WOS:A1991GP10200006 ER PT J AU GOLUB, I STROBL, K AF GOLUB, I STROBL, K TI SPATIOTEMPORAL ANALYSIS OF A NONLINEAR SANDWICHS SWITCHING BEHAVIOR SO OPTICS COMMUNICATIONS LA English DT Article ID INTERFACE AB We studied the spatio-temporal switching behavior of an all-optical Nonlinear Sandwich for the case of a negative (thermal) nonlinearity. The results indicate the potential applications of this device for energy limiting, prepulse suppression, pulse shortening and pulse shaping. RP GOLUB, I (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP CLS-5,MS E535,LOS ALAMOS,NM 87545, USA. NR 16 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD OCT 15 PY 1991 VL 86 IS 1 BP 93 EP 98 DI 10.1016/0030-4018(91)90249-D PG 6 WC Optics SC Optics GA GN335 UT WOS:A1991GN33500017 ER PT J AU TICHENOR, DA KUBIAK, GD MALINOWSKI, ME STULEN, RH HANEY, SJ BERGER, KW BROWN, LA FREEMAN, RR MANSFIELD, WM WOOD, OR TENNANT, DM BJORKHOLM, JE MACDOWELL, AA BOKOR, J JEWELL, TE WHITE, DL WINDT, DL WASKIEWICZ, WK AF TICHENOR, DA KUBIAK, GD MALINOWSKI, ME STULEN, RH HANEY, SJ BERGER, KW BROWN, LA FREEMAN, RR MANSFIELD, WM WOOD, OR TENNANT, DM BJORKHOLM, JE MACDOWELL, AA BOKOR, J JEWELL, TE WHITE, DL WINDT, DL WASKIEWICZ, WK TI DIFFRACTION-LIMITED SOFT-X-RAY PROJECTION IMAGING USING A LASER PLASMA SOURCE SO OPTICS LETTERS LA English DT Article ID MULTILAYER MIRRORS AB Projection imaging of 0.1-mu-m lines and spaces is demonstrated with a Mo/Si multilayer coated Schwarzschild objective and 14-nm illumination from a laser plasma source. This structure has been etched into a silicon wafer by using a trilevel resist and reactive ion etching. Low-contrast modulation at 0.05-Am lines and spaces is observed in polymethylmethacrylate. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. AT&T BELL LABS,HOLMDEL,NJ 07733. RP TICHENOR, DA (reprint author), SANDIA NATL LABS,POB 969,LIVERMORE,CA 94551, USA. RI Bokor, Jeffrey/A-2683-2011 NR 6 TC 36 Z9 37 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD OCT 15 PY 1991 VL 16 IS 20 BP 1557 EP 1559 DI 10.1364/OL.16.001557 PG 3 WC Optics SC Optics GA GK876 UT WOS:A1991GK87600003 PM 19777030 ER PT J AU LONGTIN, A AF LONGTIN, A TI NOISE-INDUCED TRANSITIONS AT A HOPF-BIFURCATION IN A 1ST-ORDER DELAY-DIFFERENTIAL EQUATION SO PHYSICAL REVIEW A LA English DT Article ID MULTIPLICATIVE COLORED NOISE; PUPIL LIGHT REFLEX; CHAOTIC ATTRACTORS; BISTABLE SYSTEM; ADDITIVE NOISE; OSCILLATION; SIMULATION; BEHAVIOR; FEEDBACK AB The influence of colored noise on the Hopf bifurcation in a first-order delay-differential equation (DDE), a model paradigm for nonlinear delayed feedback systems, is considered. First, it is shown, using a stability analysis, how the properties of the DDE depend on the ratio R of system delay to response time. When this ratio is small, the DDE behaves more like a low-dimensional system of ordinary differential equations (ODE's); when R is large, one obtains a singular perturbation limit in which the behavior of the DDE approaches that of a discrete time map. The relative magnitude of the additive and multiplicative noise-induced postponements of the Hopf bifurcation are numerically shown to depend on the ratio R. Although both types of postponements are minute in the large-R limit, they are almost equal due to an equivalence of additive and parametric noise for discrete time maps. When R is small, the multiplicative shift is larger than the additive one at large correlation times, but the shifts are equal for small correlation times. In fact, at constant noise power, the postponement is only slightly affected by the correlation time of the noise, except when the noise becomes white, in which case the postponement drastically decreases. This is a numerical study of the stochastic Hopf bifurcation, in ODE's or DDE's, that looks at the effect of noise correlation time at constant power. Further, it is found that the slope at the fixed point averaged over the stochastic-parameter motion acts, under certain conditions, as a quantitative indicator of oscillation onset in the presence of noise. The problem of how properties of the DDE carry over to ODE's and to maps is discussed, along with the proper theoretical framework in which to study nonequilibrium phase transitions in this class of functional differential equations. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP LONGTIN, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,COMPLEX SYST GRP,LOS ALAMOS,NM 87545, USA. RI Longtin, Andre/D-2443-2009 NR 42 TC 41 Z9 42 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 OCT 15 PY 1991 VL 44 IS 8 BP 4801 EP 4813 DI 10.1103/PhysRevA.44.4801 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000007 ER PT J AU FEDERICI, JF VALEO, EJ AF FEDERICI, JF VALEO, EJ TI 4-WAVE-MIXING AND PHASE CONJUGATION IN PLASMAS USING IONIZATION NONLINEARITIES SO PHYSICAL REVIEW A LA English DT Article ID LIQUID SUSPENSIONS; MICROSPHERES; SCATTERING; HG1-XCDXTE AB Four-wave mixing in plasmas using ponderomotive and thermal nonlinearities has been extensively studied. Plasmas have received considerable attention since they become more efficient four-wave-mixing and phase-conjugation media at longer wavelengths (far infrared, 10-mu-m, to radio wave, 10 m). In this paper, the prospect of using an ionization nonlinearity in weakly ionized plasmas for degenerate four-wave mixing and phase conjugation is discussed. Like the thermal pressure nonlinearity, the ionization nonlinearity results from the heating of the plasma by the beat wave. However, as the local temperature increases, more neutral species are ionized by electron-impact ionization to form a beat-wave grating structure, instead of pushing the electrons into a grating structure (as with the thermal and ponderomotive nonlinearities), the electron density grating is created directly by ionization. Numerical estimates of the phase-conjugate reflectivity indicate reflectivities in the range of 10(-4)-10(-3) are possible in a weakly ionized steady-state gas-discharge plasma. The reflectivity is limited to this range due to the onset of an ionization instability (striations). Larger reflectivities may be possible for pulsed plasma sources. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. NR 42 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 15 PY 1991 VL 44 IS 8 BP 5158 EP 5172 DI 10.1103/PhysRevA.44.5158 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000046 ER PT J AU YU, LH AF YU, LH TI GENERATION OF INTENSE UV-RADIATION BY SUBHARMONICALLY SEEDED SINGLE-PASS FREE-ELECTRON LASERS SO PHYSICAL REVIEW A LA English DT Article ID GAIN; WIGGLERS AB We present a detailed analysis of a subharmonically seeded single-pass free-electron laser (FEL) utilizing two wiggler magnets separated by a dispersion section. To be specific, suppose the seed to be laser light at 300 nm. A first wiggler is used to energy modulate the electron beam. This is followed by a dispersion section to produce spatial bunching, and a second wiggler resonant to 100 nm. Upon passing through the second wiggler, the prebunched electron beam first radiates coherently, and then this radiation is exponentially amplified. Finally, a tapered section is used to extract additional power from the electron beam. In this manner we can achieve pulses of duration almost-equal-to 10 psec with 1 mJ per pulse in 10(-4) bandwidth, with continuously tunable wavelength in the range 100-300 nm. We present the analytical tools we have employed for the preliminary estimate of the system performance and of the optimization of the parameters. We describe our modification of the simulation code TDA to include harmonic generation and discuss its use in analyzing the subharmonically seeded FEL. The analytic and computer-simulation calculations are in good agreement. We discuss in detail the physical process in the system and the optimization of parameters. RP YU, LH (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 21 TC 310 Z9 319 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 15 PY 1991 VL 44 IS 8 BP 5178 EP 5193 DI 10.1103/PhysRevA.44.5178 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000048 ER PT J AU LITTLEJOHN, RG FLYNN, WG AF LITTLEJOHN, RG FLYNN, WG TI GEOMETRIC PHASES IN THE ASYMPTOTIC THEORY OF COUPLED WAVE-EQUATIONS SO PHYSICAL REVIEW A LA English DT Article ID FINITE DOMAIN; CLASSICAL QUANTIZATION; ADIABATIC MOTION; PERIODIC-ORBITS; BERRY PHASE; EIGENFREQUENCIES; MECHANICS; DENSITY; FIELD; TERMS AB Traditional approaches to the asymptotic behavior of coupled wave equations have difficulties in the formulation of a consistent version of the Bohr-Sommerfeld quantization conditions. These difficulties can be circumvented by using the Weyl calculus to diagonalize the matrix of wave operators. In analyzing the diagonalized wave equations, geometric phases enter in an important way, especially in the development of Bohr-Sommerfeld quantization rules. It turns out that a version of Berry's phase is incorporated into the symplectic structure in the ray phase space, influencing the classical Hamiltonian orbits, the construction of solutions to the Hamiltonian-Jacobi equation, and the computation of action integrals. Noncanonical coordinates in the ray phase space are useful in carrying out these calculations and in making the construction of eigenvalues and wave functions manifestly gauge invariant. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP LITTLEJOHN, RG (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 45 TC 113 Z9 113 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 15 PY 1991 VL 44 IS 8 BP 5239 EP 5256 DI 10.1103/PhysRevA.44.5239 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000053 ER PT J AU GRIEM, HR IGLESIAS, CA BOERCKER, DB AF GRIEM, HR IGLESIAS, CA BOERCKER, DB TI COMPARISON OF 2ND-ORDER IMPACT LINE SHIFTS SO PHYSICAL REVIEW A LA English DT Note ID IONIZED-HELIUM LINES; ELECTRON COLLISIONS; DENSE-PLASMAS; HYDROGEN LINES; SPECTRAL-LINES AB The second-order impact shifts in hydrogen obtained from the Baranger formalism are compared with those from a kinetic theory approach. The resulting DELTA-n = 0 contributions to the shift from the two theories are shown to be identical, except for the neglect of electron-electron correlations in the Baranger formalism. It is also shown that some care is required in taking the classical limit for the perturbing electrons, or else the shift from DELTA-n = 0 interactions vanishes. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP GRIEM, HR (reprint author), UNIV MARYLAND,PLASMA RES LAB,COLLEGE PK,MD 20742, USA. NR 10 TC 2 Z9 2 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 15 PY 1991 VL 44 IS 8 BP 5318 EP 5319 DI 10.1103/PhysRevA.44.5318 PG 2 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GM060 UT WOS:A1991GM06000063 ER PT J AU MAGRI, R FROYEN, S ZUNGER, A AF MAGRI, R FROYEN, S ZUNGER, A TI ELECTRONIC-STRUCTURE AND DENSITY OF STATES OF THE RANDOM AL0.5GA0.5AS, GAAS0.5P0.5, AND GA0.5IN0.5AS SEMICONDUCTOR ALLOYS SO PHYSICAL REVIEW B LA English DT Article ID COHERENT-POTENTIAL-APPROXIMATION; SPECIAL-QUASIRANDOM-STRUCTURES; ABSORPTION FINE-STRUCTURE; VIRTUAL CRYSTAL APPROXIMATION; SITE DIAGONAL DISORDER; RANDOM SOLID-SOLUTIONS; VAPOR-PHASE EPITAXY; SHORT-RANGE ORDER; III-V ALLOYS; BAND-STRUCTURE AB The electronic density of states (DOS), charge densities, equilibrium bond lengths, and optical bowing of the direct band gaps are calculated for three perfectly random semiconductor alloys within the first-principles pseudopotential method using the concept of "special quasirandom structures" (SQS's). The SQS's are periodic structures with moderately large unit cells whose sites are occupied by atoms in a way designed to reproduce the structural features of the infinite, perfectly random substitutional alloys. In avoiding averaging over atoms (as in the virtual-crystal approximation) or over atomic environments (as in the site-coherent-potential approximation), this approach is capable of revealing the multisite nature of chemical disorder, as well as atomic-relaxation effects. We show how the existence of different local environments about chemically identical sites leads to splittings and fine structures in the density of states, and how atomic relaxations are induced by such nonsymmetric environments and lead to significant modifications in these DOS features. The calculated alloy bond lengths and optical-bowing coefficients are found to be in good agreement with experiment. Relaxation-induced splittings in the DOS are offered as predictions for future photoemission studies. RP MAGRI, R (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013; Magri, Rita/O-5267-2016 OI Magri, Rita/0000-0003-2945-0374 NR 87 TC 30 Z9 30 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 15 BP 7947 EP 7964 DI 10.1103/PhysRevB.44.7947 PG 18 WC Physics, Condensed Matter SC Physics GA GK728 UT WOS:A1991GK72800019 ER PT J AU ZHANG, BL CHAN, CT HO, KM AF ZHANG, BL CHAN, CT HO, KM TI ADSORPTION GEOMETRY AND SATURATION COVERAGE OF NA ON THE SI(100)-(2X1) SURFACE - 1ST PRINCIPLES CALCULATIONS SO PHYSICAL REVIEW B LA English DT Article ID SI(001)2X1-K SURFACE; OVERLAYER AB We have performed first-principles total-energy calculations for Na on the Si(100)-(2 X 1) surface at different coverages. At half-monolayer Na coverage [one Na atom per Si(100)-(2 X 1) unit cell], the most favorable adsorption site of Na is found to be the valley bridge site. At one-monolayer Na coverage [two Na atoms per Si(100)-(2 X 1) unit cell], the Na atoms occupy both the valley bridge sites and the pedestal sites. The one-monolayer-coverage models have substantially lower surface energies than the half-monolayer-coverage models, indicating that the saturation coverage should be one monolayer. We also found that the surface is metallic at half-monolayer Na coverage and semiconducting at one-monolayer coverage. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP ZHANG, BL (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 22 TC 26 Z9 26 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 15 BP 8210 EP 8213 DI 10.1103/PhysRevB.44.8210 PG 4 WC Physics, Condensed Matter SC Physics GA GK728 UT WOS:A1991GK72800047 ER PT J AU FROTA, HO AF FROTA, HO TI CHARGE SUSCEPTIBILITY OF THE SPIN-DEGENERATE ANDERSON MODEL SO PHYSICAL REVIEW B LA English DT Article ID RENORMALIZATION-GROUP APPROACH; DILUTE MAGNETIC-ALLOYS; X-RAY PHOTOEMISSION; CE COMPOUNDS; STATIC PROPERTIES; LEVEL; SPECTRA; METALS AB We calculated the charge susceptibility of the Anderson model for finite f-f Coulomb interaction U, via a renormalization-group technique. For an occupation number of the f orbital around unity, the spectrum presents two peaks. One peak is centered at the impurity orbital energy \epsilon-f\, and comes from the transition f0 --> f1. The other one is centered at the energy epsilon-f + U. It is associated with the transition f1 --> f2, and decreases in intensity with the increasing of U. C1 UNIV AMAZONAS,INST CIENCIAS EXATAS,DEPT FIS,BR-69068 MANAUS,BRAZIL. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP FROTA, HO (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 8433 EP 8436 DI 10.1103/PhysRevB.44.8433 PG 4 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400001 ER PT J AU FAULKNER, JS HORVATH, EA NICHOLSON, DM AF FAULKNER, JS HORVATH, EA NICHOLSON, DM TI MULTIPLE-SCATTERING THEORY AND THE QUADRATIC KORRINGA-KOHN-ROSTOKER METHOD SO PHYSICAL REVIEW B LA English DT Article ID BAND THEORY; POTENTIALS AB It has been demonstrated that the quadratic Korringa-Kohn-Rostoker method is a fast and reliable technique for band-theory calculations with full self-consistent potential functions. The question addressed here is whether there are approximations to be made in the theory that will provide considerable simplifications in its application without introducing unacceptable errors. Two such approximations are discussed: a perturbative method for dealing with the quadratic terms and a noniterative approximation to the scattering matrices. It will be shown that some of our results are of interest in the more general context of multiple-scattering theory. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. FLORIDA ATLANTIC UNIV,DEPT PHYS,BOCA RATON,FL 33431. RP FAULKNER, JS (reprint author), FLORIDA ATLANTIC UNIV,ALLOY RES CTR,BOCA RATON,FL 33431, USA. NR 14 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 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 8467 EP 8472 DI 10.1103/PhysRevB.44.8467 PG 6 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400006 ER PT J AU KIM, KJ HARMON, BN LYNCH, DW KOELLING, DD AF KIM, KJ HARMON, BN LYNCH, DW KOELLING, DD TI LARGE LOW-ENERGY OSCILLATOR STRENGTH FOR CE 4F ELECTRONS IN THE SOLID-STATE SO PHYSICAL REVIEW B LA English DT Article AB The conductivity sum rule applied to LaSn3, CeSn3, LaB6, and CeB6 between 1.5 and 4.35 eV shows that there is approximately one more electron contributing to the optical conductivity of the Ce compounds than to that of the analogous La compounds. From the data and band calculations we conclude that about 0.5 Ce 4f electron per atom contributes as initial states for CeSn3 in the above energy range, and about half that number of 4f electrons serve as initial states in LaSn3. This shift of oscillator strength from higher energies for atoms to lower energies for solids is attributed to hybridization. Much of the remaining Ce-La difference is from transitions to p-like final states, which are reduced in the La compounds due to hybridization with unoccupied 4f states. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. ARGONNE NATL LAB,DIV MAT SCI & TECHNOL,ARGONNE,IL 60439. RP KIM, KJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011, USA. NR 13 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 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 8526 EP 8528 DI 10.1103/PhysRevB.44.8526 PG 3 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400012 ER PT J AU SINGH, PP DEFONTAINE, D GONIS, A AF SINGH, PP DEFONTAINE, D GONIS, A TI SELF-CONSISTENT-FIELD KORRINGA-KOHN-ROSTOKER COHERENT-POTENTIAL-APPROXIMATION CALCULATIONS IN THE ATOMIC-SPHERE APPROXIMATION SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; ALLOYS; BAND; DENSITY; STATES; PD AB We have extended the recently formulated Korringa-Kohn-Rostoker coherent-potential approximation (KKR-CPA) for the treatment of substitutionally disordered alloys within the KKR atomic-spheres approximation (ASA) to include charge self-consistency. To test the accuracy of the present approach we have carried out self-consistent-field (SCF) KKR-ASA-CPA calculations of Cu-Pd alloys. Our results are in good agreement with experimental results and previous SCF-KKR-CPA calculations. We also present a comparison of the electronic structures of the ordered with the disordered Cu-Pd alloys. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP SINGH, PP (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 17 TC 11 Z9 11 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 8578 EP 8583 DI 10.1103/PhysRevB.44.8578 PG 6 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400019 ER PT J AU MAGRI, R ZUNGER, A AF MAGRI, R ZUNGER, A TI REAL-SPACE DESCRIPTION OF SEMICONDUCTING BAND-GAPS IN SUBSTITUTIONAL SYSTEMS SO PHYSICAL REVIEW B LA English DT Article ID SPECIAL QUASIRANDOM STRUCTURES; TRANSITION-METAL ALLOYS; ORDERED BINARY-ALLOYS; PHASE-DIAGRAMS; 1ST-PRINCIPLES CALCULATION; ELECTRONIC-PROPERTIES; GROUND STATE; CU-AU; AG-AU; SUPERLATTICES AB The goal of "band-gap engineering" in substitutional lattices is to identify atomic configurations that would give rise to a desired value of the band gap. Yet, current theoretical approaches to the problems, based largely on compilations of band structures for various latice configurations, have not yielded simple rules relating structural motifs to band gaps. We show that the band gap of substitutional AlAs/GaAs lattices can be usefully expanded in terms of a hierarchy of contributions from real-space "atomic figures" (pairs, triplets, quadruplets) determined from first-principles band-structure calculations. Pair figures (up to fourth neighbors) and three-body figures are dominant. In analogy with similar cluster expansions of the total energy, this permits a systematic search among all lattice configurations for those having "special" band gaps. This approach enables the design of substitutional systems with certain band-gap properties by assembling atomic figures. As an illustration, we predict that the [012BAR]-oriented (AlAs)1/(GaAs)4/(AlAs)1/(GaAs)2 superlattice has the largest band gap among all Al0.25Ga0.75As lattices with a maximum of ten cations per unit cell. RP SOLAR ENERGY RES INST, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013; Magri, Rita/O-5267-2016 OI Magri, Rita/0000-0003-2945-0374 NR 69 TC 15 Z9 15 U1 2 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 8672 EP 8684 DI 10.1103/PhysRevB.44.8672 PG 13 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400028 ER PT J AU QIANG, H POLLAK, FH MAILHIOT, C PETTIT, GD WOODALL, JM AF QIANG, H POLLAK, FH MAILHIOT, C PETTIT, GD WOODALL, JM TI EXTERNALLY GENERATED PIEZOELECTRIC EFFECT IN SEMICONDUCTOR MICROSTRUCTURES SO PHYSICAL REVIEW B LA English DT Note ID ELECTRIC-FIELD DEPENDENCE; QUANTUM-WELL STRUCTURES; UNIAXIAL-STRESS; TEMPERATURE; STRAIN AB We report a study of the effects of large, external uniaxial stress (T) along [100] and [110] on the optical properties of a strained layer (001) In0.21Ga0.79As/GaAs single quantum well. For T parrell-to [110] we have observed a redshift of several peaks and an increase in the intensities of several "symmetry-forbidden" transitions; effects not seen for T parrell-to [100]. This phenomenon is due to an electric field along [001] induced by the piezoelectric coupling for T parrell-to [110]. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. CUNY GRAD SCH & UNIV CTR,NEW YORK,NY 10036. RP QIANG, H (reprint author), CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210, USA. NR 17 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 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD OCT 15 PY 1991 VL 44 IS 16 BP 9126 EP 9128 DI 10.1103/PhysRevB.44.9126 PG 3 WC Physics, Condensed Matter SC Physics GA GN304 UT WOS:A1991GN30400095 ER PT J AU DIFFENBACH, RA HILTERMAN, MJ FROMMELL, EA BOOHER, HB HEDGES, SW AF DIFFENBACH, RA HILTERMAN, MJ FROMMELL, EA BOOHER, HB HEDGES, SW TI CHARACTERIZATION OF CALCIUM-OXIDE FLY-ASH SORBENTS FOR SO2 REMOVAL SO THERMOCHIMICA ACTA LA English DT Article ID DESULFURIZATION; INJECTION; SOLIDS; GAS AB Sorbents for SO2 removal from humidified simulated flue gas have been prepared from CaO-fly ash slurries using a pressure hydration technique. The fly ash materials were obtained from the combustion of four bituminous, six sub-bituminous, and two lignite coals. The CaO/fly ash ratio, and the slurry reaction time and temperature were varied in the preparation step. The sorbents were characterized by measuring thermogravimetrically the SO2 uptake from flue gas, and by X-ray diffraction, surface area, particle size, and optical microscopy studies. The X-ray diffraction results indicated that calcium silicate hydrate, Ca2SiO4.H2O, and calcium aluminum silicate hydroxide, Ca3Al2(SiO4)(OH)8, were the principal Ca-containing species formed during the hydrothermal reaction between CaO and fly ash. There was a good correlation between the surface area of the sorbent and the SO2 uptake. Particle size measurements and optical microscopy studies indicated that the glass-like spheres in fly ash remained largely intact during the hydrothermal preparation step. RP DIFFENBACH, RA (reprint author), PITTSBURGH ENERGY TECHNOL CTR,PITTSBURGH,PA 15236, USA. NR 18 TC 22 Z9 24 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD OCT 15 PY 1991 VL 189 IS 1 BP 1 EP 24 DI 10.1016/0040-6031(91)87096-F PG 24 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA GM369 UT WOS:A1991GM36900001 ER PT J AU HANNA, MC MAJERFELD, A SZMYD, DM AF HANNA, MC MAJERFELD, A SZMYD, DM TI STRAIN RELAXATION AND COMPENSATION DUE TO ANNEALING IN HEAVILY CARBON-DOPED GAAS SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; GROWTH AB Heavily C-doped GaAs grown by atmospheric pressure metalorganic vapor phase epitaxy using CCl4 as the C-dopant source has been annealed to study the stability of C acceptors at very high doping levels (p = 10(18)-10(20) cm-3). In layers with initial hole densities p > 6 x 10(19) cm-3, 5 min anneals at temperatures ranging from 700 to 850-degrees-C under arsine overpressure caused a significant reduction in the hole density, lattice contraction and photoluminescence intensity, and a smaller reduction in the mobility. For lower doped material, annealing has little effect on the as-grown properties. These changes in the material properties indicate that a compensating recombination center is formed during annealing. Possible compensation mechanisms which explain partially the annealing effects in very heavily C-doped GaAs are analyzed. The results of this study show that there is an upper limit on the hole concentration of p > 6 x 10(19) cm-3 in annealed GaAs:C. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP HANNA, MC (reprint author), UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309, USA. NR 15 TC 33 Z9 33 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 14 PY 1991 VL 59 IS 16 BP 2001 EP 2003 DI 10.1063/1.106167 PG 3 WC Physics, Applied SC Physics GA GJ638 UT WOS:A1991GJ63800028 ER PT J AU NAHUM, M VERGHESE, S RICHARDS, PL CHAR, K AF NAHUM, M VERGHESE, S RICHARDS, PL CHAR, K TI THERMAL-BOUNDARY RESISTANCE FOR YBA2CU3O7-DELTA FILMS SO APPLIED PHYSICS LETTERS LA English DT Article ID SUPERCONDUCTING THIN-FILMS; BA-CU-O; OPTICAL-RESPONSE; EPITAXIAL-FILMS; TEMPERATURES AB We have made direct measurements of the thermal boundary resistance, R(bd), between high quality epitaxial films of YBa2Cu3O7-delta and a variety of substrates with and without buffer layers. The boundary resistance was deduced from measurements of the electrical resistance changes in three parallel strips of YBa2Cu3O7-delta when one was electrically heated. Our measurements indicate that R(bd) is weakly dependent on temperature and, for all the measured samples, has a value of 0.8-1.4 x 10(-3) K cm2/W between 90 and 200 K, which is a factor of almost-equal-to 80 larger than the prediction of the acoustic mismatch model at 100 K. The thermal response time of almost-equal-to 1 ns which results from the heat capacity of the film and R(bd) is observed in many experiments with pulsed laser sources. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. CONDUCTUS INC,SUNNYVALE,CA 94086. RP NAHUM, M (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 23 TC 122 Z9 122 U1 2 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 14 PY 1991 VL 59 IS 16 BP 2034 EP 2036 DI 10.1063/1.106123 PG 3 WC Physics, Applied SC Physics GA GJ638 UT WOS:A1991GJ63800039 ER PT J AU LUO, L WU, XD DYE, RC MUENCHAUSEN, RE FOLTYN, SR COULTER, Y MAGGIORE, CJ INOUE, T AF LUO, L WU, XD DYE, RC MUENCHAUSEN, RE FOLTYN, SR COULTER, Y MAGGIORE, CJ INOUE, T TI A-AXIS ORIENTED YBA2CU3O7-X THIN-FILMS ON SI WITH CEO2 BUFFER LAYERS SO APPLIED PHYSICS LETTERS LA English DT Article ID DEPOSITION; GROWTH AB We have grown a-axis oriented YBa2Cu3O7-x (YBCO) thin films on Si(100) substrates with (110) oriented insulating buffer layers of cerium dioxide (CeO2) using the pulsed laser deposition technique. The films are highly oriented and textured as determined by theta-2-theta x-ray diffraction, x-ray pole-figure scan, scanning electron microscopy, Rutherford backscattering spectroscopy, and ion channeling. No diffusion at the interface has been found at growth temperatures up to 760-degrees-C, indicating the CeO2 is a chemically stable and structurally compatible intermediate material for the growth of YBCO on Si. A zero resistance superconducting transition temperature of 87 K and a critical-current density (J(c)) of 1.5 x 10(5) A/cm2 at 75 K have been measured; J(c) obtained represents the highest value for the a-axis oriented YBCO films. C1 IWAKI MEISEI UNIV,DEPT ELECTR & ENGN,IWAKI,FUKUSHIMA 970,JAPAN. RP LUO, L (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 16 TC 106 Z9 109 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 14 PY 1991 VL 59 IS 16 BP 2043 EP 2045 DI 10.1063/1.106126 PG 3 WC Physics, Applied SC Physics GA GJ638 UT WOS:A1991GJ63800042 ER PT J AU HODGDON, ML NAVARRO, R CAMPBELL, LJ AF HODGDON, ML NAVARRO, R CAMPBELL, LJ TI MEISSNER-STATE DIAMAGNETISM IN GRANULAR HIGH-TC SUPERCONDUCTORS SO EUROPHYSICS LETTERS LA English DT Article ID MICROSTRUCTURE AB The diamagnetic interactions between Meissner-state superconducting grains are studied by explicit solution of finite clusters of 2, 4, and 6 diamagnetic spheres and by effective medium theories in the infinite-sphere limit. The compression of magnetic field between two spheres found by Waysand (Europhys. Lett., 5 (1988) 73) is shown to be strongly dependent on orientation and sharply reduced by shielding inside clusters with more than two spheres. When the number of spheres goes to infinity, effective medium theories predict generic average intergranular fields smaller than the applied field, but specific values depend on the macroscopic shape of the sphere cluster. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP HODGDON, ML (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV DYNAM TESTING,LOS ALAMOS,NM 87545, USA. NR 12 TC 15 Z9 15 U1 0 U2 0 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 OCT 14 PY 1991 VL 16 IS 7 BP 677 EP 682 DI 10.1209/0295-5075/16/7/012 PG 6 WC Physics, Multidisciplinary SC Physics GA GL092 UT WOS:A1991GL09200012 ER PT J AU BARBIERI, R HALL, LJ AF BARBIERI, R HALL, LJ TI FLAVON MODELS FOR THE 17 KEV NEUTRINO SO NUCLEAR PHYSICS B LA English DT Article ID DIRAC NEUTRINOS; LEPTON NUMBER; BETA-DECAY; NUCLEOSYNTHESIS; CONSTRAINTS; MASSES AB Models for a 17 keV neutrino based on the symmetry breaking U(1)e x U(1)mu x U(1)tau --> U(1) (e - mu + tau) are discussed. The models involve only the three usual neutrinos (which are naturally light), have no new symmetry breaking beneath the weak scale and have lifetimes for the 17 keV neutrino as short as 0.1 s. Unusual signatures are discussed for tau decays, Higgs decays and supernova neutrinos. C1 IST NAZL FIS NUCL,PISA,ITALY. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV PHYS,THEORET PHYS GRP,BERKELEY,CA 94720. RP BARBIERI, R (reprint author), UNIV PISA,DEPT PHYS,I-56100 PISA,ITALY. NR 23 TC 32 Z9 32 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD OCT 14 PY 1991 VL 364 IS 1 BP 27 EP 42 DI 10.1016/0550-3213(91)90576-J PG 16 WC Physics, Particles & Fields SC Physics GA GL463 UT WOS:A1991GL46300003 ER PT J AU JIANG, X WOCHNER, P MOSS, SC ZSCHACK, P AF JIANG, X WOCHNER, P MOSS, SC ZSCHACK, P TI DIFFUSE-X-RAY SCATTERING STUDY OF AN OXYGEN-DISORDERED TETRAGONAL YBA2(CU0.955AL0.045)3O7 CRYSTAL SO PHYSICAL REVIEW LETTERS LA English DT Article ID NI-AL ALLOYS; TWEED MICROSTRUCTURES; NEUTRON-SCATTERING; SUPERCONDUCTIVITY; YBA2CU3O7-DELTA; YBA2(CU1-XFEX)3O7-DELTA; SUBSTITUTION; TEMPERATURE; IMPURITIES; BA2YCU3O7 AB X-ray scattering from a tetragonal single crystal of YBa2(Cu0.955Al0.045)3O7 shows diffuse streaking in [110] directions about the Bragg peaks. Through a quantitative calculation using a coupled concentration wave, static displacement wave approach, we show that this is essentially attributable to the shear displacement field produced by a disordered oxygen array on the Cu(1)-O "chain" plane. We also observe pronounced short-range chain order (local orthorhombic fluctuations) whose correlation range is considerably greater than the superconducting coherence length. This suggests that on a scale relevant for superconductivity the (local) orthorhombicity remains important in this tetragonal structure. C1 BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,OAK RIDGE ASSOCIATED UNIV,UPTON,NY 11973. UNIV HOUSTON,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77204. RP JIANG, X (reprint author), UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204, USA. NR 36 TC 40 Z9 40 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 OCT 14 PY 1991 VL 67 IS 16 BP 2167 EP 2170 DI 10.1103/PhysRevLett.67.2167 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ640 UT WOS:A1991GJ64000014 ER PT J AU SCHWOEBEL, PR PANITZ, JA AF SCHWOEBEL, PR PANITZ, JA TI ION EMISSION FROM LIQUID LITHIUM FOR INERTIAL-CONFINEMENT-FUSION APPLICATIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID MECHANISM AB The first experimental studies of pulsed electrohydrodynamic ion emission from molten lithium are reported. Ions are produced at the apices of cusps formed on the surface of liquid lithium by applying a pulsed electric field of nanosecond duration. The ion species are dominated by Li-7+ and have a turn-on time of less than 10 ns as measured by time-of-flight mass spectroscopy. Current densities of approximately 300 A/cm2 have been observed. Implications for the use of this ion source in light-ion inertial-confinement-fusion reactors are discussed. C1 UNIV NEW MEXICO,DEPT PHYS,ALBUQUERQUE,NM 87131. RP SCHWOEBEL, PR (reprint author), SANDIA NATL LABS,DIV 1275,ALBUQUERQUE,NM 87185, USA. NR 18 TC 2 Z9 2 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 OCT 14 PY 1991 VL 67 IS 16 BP 2175 EP 2178 DI 10.1103/PhysRevLett.67.2175 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ640 UT WOS:A1991GJ64000016 ER PT J AU LIU, JX WAN, JC GOLDMAN, AM CHANG, YC JIANG, PZ AF LIU, JX WAN, JC GOLDMAN, AM CHANG, YC JIANG, PZ TI FEATURES OF THE DENSITY OF STATES OF HIGH-TC SUPERCONDUCTORS PROBED BY VACUUM TUNNELING SO PHYSICAL REVIEW LETTERS LA English DT Article ID CA-CU-O; SINGLE-CRYSTALS; ENERGY-GAP; SPECTROSCOPY AB A scanning tunneling microscope has been used to study Bi2Sr2CaCu2Ox single crystals with transition temperatures of 85 K. Images of atoms and topographical features were obtained at low temperatures and spectra were acquired in the vacuum tunneling mode. Interpretations of the conductance data suggest that 2-DELTA/k(B)T(c) almost-equal-to 8.2. Most significantly, an additional conductance peak at 90 meV, suggesting a localized state, is observed. The latter would appear to support the marginal-Fermi-liquid picture. C1 UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. ARGONNE NATL LAB,ARGONNE,IL 60439. RP LIU, JX (reprint author), UNIV MINNESOTA,CTR SCI & APPLICAT SUPERCONDUCT,MINNEAPOLIS,MN 55455, USA. NR 26 TC 91 Z9 93 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 OCT 14 PY 1991 VL 67 IS 16 BP 2195 EP 2198 DI 10.1103/PhysRevLett.67.2195 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ640 UT WOS:A1991GJ64000021 ER PT J AU WILLS, JM ERIKSSON, O BORING, AM AF WILLS, JM ERIKSSON, O BORING, AM TI THEORETICAL-STUDIES OF THE HIGH-PRESSURE PHASES IN CERIUM SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRYSTAL-STRUCTURE; ELECTRONIC-STRUCTURE; VOLUME COLLAPSE; GROUND-STATE; BAND; TRANSITION; SYSTEMS; METAL; CE AB We present full potential linear-muffin-tin-orbital calculations based on the local-density approximation, which reproduce the T = 0 phase diagram of cerium (Ce), including the volumes and transition pressures for both the a --> a', and the a' --> bct transitions. The a --> a' transition is largely determined by a balance of two competing terms: a Madelung term and a 4f one-electron term. The a' --> bct transition is driven by both 4f and 5d partial-wave contributions. This is the first successful, ab initio calculation of a crystallographic (T = 0) phase diagram of an f-electron system. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP WILLS, JM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 32 TC 44 Z9 44 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD OCT 14 PY 1991 VL 67 IS 16 BP 2215 EP 2218 DI 10.1103/PhysRevLett.67.2215 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ640 UT WOS:A1991GJ64000026 ER PT J AU KIM, YH CHEONG, SW FISK, Z AF KIM, YH CHEONG, SW FISK, Z TI DYNAMICS OF PHOTOGENERATED CHARGE-CARRIERS IN CUPRATES SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLE-CRYSTALS; GAP; SUPERCONDUCTIVITY; LA2CUO4 AB New results of infrared photoexcitation experiments on undoped La2CuO4 and Nd2CuO4 are reported. We observed two broad electronic excitations within the charge-transfer energy gap and an associated phonon bleaching, possibly originating from strong charge-lattice coupling. Our results are discussed in terms of the condensation of self-localized photocarriers in the CuO2 planes at low temperatures. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP KIM, YH (reprint author), UNIV CINCINNATI,DEPT PHYS,CINCINNATI,OH 45221, USA. NR 23 TC 43 Z9 43 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD OCT 14 PY 1991 VL 67 IS 16 BP 2227 EP 2230 DI 10.1103/PhysRevLett.67.2227 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ640 UT WOS:A1991GJ64000029 ER PT J AU GILMAN, J AF GILMAN, J TI WHY INDUSTRY FIGHTS SHY OF SPACE SO NEW SCIENTIST LA English DT Editorial Material RP GILMAN, J (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 SN 0262-4079 J9 NEW SCI JI New Sci. PD OCT 12 PY 1991 VL 132 IS 1790 BP 63 EP 63 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GK146 UT WOS:A1991GK14600043 ER PT J AU CURTISS, LA POPLE, JA AF CURTISS, LA POPLE, JA TI A REEXAMINATION OF THE BE-OH2 COMPLEX SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULAR-ORBITAL METHODS; BASIS-SETS; PERTURBATION-THEORY; LI AB Ab initio molecular orbital calculations using large basis sets and Moller-Plesset perturbation theory to fourth order have been used to re-examine the Be-OH2 complex. The potential energy surface is found to have inner and outer minima separated by a barrier of about 2 kcal/mol. The inner minimum (Be-O distance of 1.74 angstrom) has a well-depth of about 1 kcal/mol and the outer minimum (Be-O distance of about 3.2 angstrom) has a well-depth of about 0.5 kcal/mol. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. CARNEGIE MELLON UNIV,DEPT CHEM,PITTSBURGH,PA 15213. RP CURTISS, LA (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439, 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 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD OCT 11 PY 1991 VL 185 IS 1-2 BP 159 EP 164 DI 10.1016/0009-2614(91)80157-S PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GM155 UT WOS:A1991GM15500028 ER PT J AU BRITT, PF BUCHANAN, AC AF BRITT, PF BUCHANAN, AC TI THERMOLYSIS OF SURFACE-ATTACHED 1,4-DIPHENYLBUTANE - THE ROLE OF HYDROGEN-TRANSFER REACTIONS ON THE SURFACE IN DETERMINING THE PRODUCT DISTRIBUTION SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID MODEL COMPOUNDS; COAL; 1,3-DIPHENYLPROPANE; DECOMPOSITION; CHEMISTRY; RADICALS; BIBENZYL; CLEAVAGE AB In order to probe the effects of restricted radical and substrate mobility on a complex free-radical-chain decomposition reaction, a surface-immobilized 1,4-diphenylbutane (almost-equal-to DPB) has been prepared by the condensation of p-(4-phenylbutyl)phenol with the surface hydroxyl groups of a high-purity fumed silica. Thermolysis of almost-equal-to DPB was studied at 400-degrees-C as a function of surface coverage (0.504-0.054 mmol g-1), conversion, and coattached biphenyl (almost-equal-to BP) or diphenylmethane (almost-equal-to DPM). Decomposition of almost-equal-to DPB proceeds by a free-radical-chain pathway, analogous to that found for 1,4-diphenylbutane in the liquid phase, to produce as the major product pairs PhCH3 plus almost-equal-to PhCH2CH = CH2, PhCH2CH3 plus almost-equal-to PhCH = CH2, PhCH = CH2 plus almost-equal-to PhCH2CH3, and PhCH2CH = CH2 plus almost-equal-to PhCH3, whose distribution is a sensitive function of surface coverage, conversion, and structure of coattached molecules. At saturated surface coverages, bimolecular hydrogen-transfer reactions can occur on the surface to equilibrate benzylic and aliphatic radical sites such that all products are formed in nearly equal amounts. However, at lower surface coverages, the bimolecular hydrogen-transfer reactions are hindered by the spatial distribution of the molecules. At all coverages, an unusual regioselectivity is observed in the hydrogen-transfer reaction that favors the formation of the benzylic radical farthest from the surface as the proximity of almost-equal-to DPB molecules and hydrogen-abstracting radicals on the surface decrease. Coattached almost-equal-to BP is found to hinder the bimolecular hydrogen-transfer reactions on the surface, while coattached almost-equal-to DPM facilitates these reactions. These results show that radical centers can be relayed across the surface by a series of rapid hydrogen-transfer reactions to positions near unreacted almost-equal-to DPB molecules, which can lead to rapid equilibration of the benzylic and aliphatic radical sites. The implication of these results to the decomposition of aliphatic linkages connecting aromatic clusters in coal is discussed. RP BRITT, PF (reprint author), OAK RIDGE NATL LAB,DIV CHEM,POB 2008,OAK RIDGE,TN 37381, USA. NR 39 TC 20 Z9 20 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD OCT 11 PY 1991 VL 56 IS 21 BP 6132 EP 6140 DI 10.1021/jo00021a032 PG 9 WC Chemistry, Organic SC Chemistry GA GK452 UT WOS:A1991GK45200032 ER PT J AU WANDEL, A LIANG, EP AF WANDEL, A LIANG, EP TI HYBRID ACCRETION DISKS IN ACTIVE GALACTIC NUCLEI .1. STRUCTURE AND SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION; GALAXIES, NUCLEI ID X-RAY SOURCES; MASSIVE BLACK-HOLES; MAGNETIC VISCOSITY; BINARY-SYSTEMS; CYGNUS X-1; VARIABILITY; PLASMAS; MODELS; COMPTONIZATION; INSTABILITY AB We provide a unified treatment of the two distinct states of vertically thin AGN accretion disks: a cool (T approximately 10(6) K) optically thick solution, and a hot (T(e) approximately 10(9) K, optically thin solution. We introduce a generalized formalism and a new radiative cooling equation valid in both regimes. We find a new luminosity limit L < L(E) at which the hot and cool alpha-solutions merge into a single solution of intermediate optical depth. For the hot solutions we consider four cases: different ion and electron temperatures or ions and electrons in thermal equilibrium, with Comptonized bremsstrahlung or unsaturated Compton cooling. Analytic solutions for the disk structure are given, and output spectra are computed numerically. This is used to demonstrate the prospect of fitting AGN broad-band spectra, containing both the UV bump as well as hard X-ray and gamma-ray tail, using a single accretion disk model. Such models make definite predictions on the observed spectrum, such as the relation between the hard X-ray spectral index, the UV-to-X-ray luminosity ratio, and a approximately 1 MeV feature. C1 WEIZMANN INST SCI,IL-76100 REHOVOT,ISRAEL. RICE UNIV,DEPT SPACE PHYS & ASTRON,HOUSTON,TX 77251. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550. RP WANDEL, A (reprint author), HEBREW UNIV JERUSALEM,RACAH INST PHYS,JERUSALEM,ISRAEL. NR 38 TC 84 Z9 86 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 1991 VL 380 IS 1 BP 84 EP 97 DI 10.1086/170564 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH912 UT WOS:A1991GH91200010 ER PT J AU SCHINDLER, K HESSE, M BIRN, J AF SCHINDLER, K HESSE, M BIRN, J TI MAGNETIC-FIELD ALIGNED ELECTRIC POTENTIALS IN NONIDEAL PLASMA FLOWS SO ASTROPHYSICAL JOURNAL LA English DT Article DE EARTH, GENERAL; HYDROMAGNETICS; PLASMAS; SUN, FLARES ID ACCELERATION; RECONNECTION; ALTITUDE; M82 AB In this paper we discuss the electric field component parallel to the magnetic field arising from plasma flows which violate the frozen-in field condition of ideal magnetohydrodynamics. The quantity of interest is the potential U = -integral E parallel-to ds where the integral is extended along field lines. It is shown that U can be directly related to magnetic field properties, expressed by Euler potentials, even when time-dependence is included. Our results are applicable to Earth's magnetosphere, to solar flares, to aligned-rotator models of compact objects, and to galactic rotation. On the basis of order-of-magnitude estimates, our results support the view that parallel electric fields associated with nonideal plasma flows might play an important role in cosmic particle acceleration. C1 RUHR UNIV BOCHUM,W-4630 BOCHUM,GERMANY. RP SCHINDLER, K (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Hesse, Michael/D-2031-2012 NR 40 TC 56 Z9 56 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 1991 VL 380 IS 1 BP 293 EP 301 DI 10.1086/170586 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH912 UT WOS:A1991GH91200032 ER PT J AU PATTON, HJ ZANDT, G AF PATTON, HJ ZANDT, G TI SEISMIC MOMENT TENSORS OF WESTERN UNITED-STATES EARTHQUAKES AND IMPLICATIONS FOR THE TECTONIC STRESS-FIELD SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GREAT-BASIN; CONTEMPORARY TECTONICS; NORTHERN CALIFORNIA; FOCAL MECHANISMS; SURFACE-WAVES; BORAH PEAK; RANGE; PLATEAU; NEVADA; UTAH AB Using a linear inversion method applied to regional surface wave data, we have determined seismic moment tensors for 50 earthquakes in the western United States. Regional surface waves are well suited for studying moderate-sized earthquakes (4 < M < 5) located outside of local seismic networks for which first-motion solutions are difficult to obtain and seismic moment estimates are problematic due to clipping of local P and S wave recordings. We compared the inversion results to P wave first-motion solutions for 17 of the 50 events, and our comparison shows much better agreement in the orientations of the T axis than for the P axis. This could be related to the sensitivity of both methods to focal depth estimates. The surface wave results yielded a very uniform and consistent data set of stress orientations. The T axis is uniformly horizontal for all areas sampled, with E-W extension across northern California, northern Nevada, and into north central Utah; ESE-WNW extension in southern Nevada; and ENE-WSW extension in Idaho, north of the Snake River Plain. The P axis shows more variability than the T axis on local as well as regional distance scales. In the Great Basin, the results indicate a N-S change in the relative magnitude of the vertical to maximum horizontal compressive stress, with most earthquakes showing normal faulting in the Battle Mountain region and strike-slip faulting in southern Nevada. The direction of maximum horizontal compressive stress is mainly N-S in northern California and western Oregon. Our results, along with the results of Zoback et al. (1981) for central California, indicate a 60-degrees rotation of the maximum horizontal compressive stress between northern and central segments of the San Andreas fault system. A change in stress state along the northern segment could be related to the thermal and mechanical evolution of the Pacific-North American plate boundary. RP PATTON, HJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT EARTH SCI,LIVERMORE,CA 94550, USA. NR 35 TC 49 Z9 52 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD OCT 10 PY 1991 VL 96 IS B11 BP 18245 EP 18259 DI 10.1029/91JB01838 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GK023 UT WOS:A1991GK02300022 ER PT J AU GIVEON, A AF GIVEON, A TI TARGET SPACE DUALITY AND STRINGY BLACK-HOLES SO MODERN PHYSICS LETTERS A LA English DT Article AB Target space duality symmetry of the SL(2, IR)/U(1) background leads to stringy properties of the black hole. For a Euclidean space-time the semi-infinite cigar is transformed to an infinite funnel. High and low temperatures of the black hole are related. For a Lorentzian space-time, duality interchanges regions I and V in the Kruskal-Szekeres coordinates, that is, duality exchanges the horizon with the singularity. As a result, a signal can be sent out of the singularity. Such a signal is associated with the string winding modes. The mass of the black hole and the consequence of a tachyon disturbance are discussed. RP GIVEON, A (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV PHYS,THEORET PHYS GRP,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 0 TC 84 Z9 84 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-7323 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD OCT 10 PY 1991 VL 6 IS 31 BP 2843 EP 2854 DI 10.1142/S0217732391003316 PG 12 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA GJ784 UT WOS:A1991GJ78400002 ER PT J AU HOLBROOK, SR CHEONG, CJ TINOCO, I KIM, SH AF HOLBROOK, SR CHEONG, CJ TINOCO, I KIM, SH TI CRYSTAL-STRUCTURE OF AN RNA DOUBLE HELIX INCORPORATING A TRACK OF NON-WATSON-CRICK BASE-PAIRS SO NATURE LA English DT Article ID DNA; MISMATCHES AB THE crystal structure of the RNA dodecamer duplex (r-GGACUUCGGUCC)2 has been determined. The dodecamers stack end-to-end in the crystal, simulating infinite A-form helices with only a break in the phosphodiester chain. These infinite helices are held together in the crystal by hydrogen bonding between ribose hydroxyl groups and a variety of donors and acceptors. The four noncomplementary nucleotides in the middle of the sequence did not form an internal loop, but rather a highly regular double-helix incorporating the non-Watson-Crick base pairs, G . U and U . C. This is the first direct observation of a U . C (or T . C) base pair in a crystal structure. The U . C pairs each form only a single base-base hydrogen bond, but are stabilized by a water molecule which bridges between the ring nitrogens and by four waters in the major groove which link the bases and phosphates. The lack of distortion introduced in the double helix by the U . C mismatch may explain its low efficiency of repair in DNA. The G . U wobble pair is also stabilized by a minor-groove water which bridges between the unpaired guanine amino and the ribose hydroxyl of the uracil. This structure emphasizes the importance of specific hydrogen bonding between not only the nucleotide bases, but also the ribose hydroxyls, phosphate oxygens and tightly bound waters in stabilization of the intramolecular and intermolecular structures of double helical RNA. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP HOLBROOK, SR (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 18 TC 296 Z9 297 U1 2 U2 7 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD OCT 10 PY 1991 VL 353 IS 6344 BP 579 EP 581 DI 10.1038/353579a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GJ643 UT WOS:A1991GJ64300075 PM 1922368 ER PT J AU TATCHYN, R WINICK, H AF TATCHYN, R WINICK, H TI SSRL 1990 - STATUS AND FUTURE-PLANS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9TH USSR NATIONAL CONF ON SYNCHROTRON RADIATION UTILIZATION ( SR 90 ) CY JUN 26-29, 1990 CL MOSCOW, USSR SP ACAD SCI USSR, P N LEBEDEV PHYS INST, MOSCOW STATE UNIV, ACAD SCI USSR, SYNCHROTRON RADIAT COMMISS ID SYNCHROTRON RADIATION; PEP AB The present status and future directions of scientific, machine, and insertion device research at the Stanford Synchrotron Radiation Laboratory (SSRL) are reviewed. A central focus is on the transformation of SPEAR into a fully dedicated synchrotron radiation (SR) source with a dedicated 3 GeV injector synchrotron. Recently implemented upgrades of SPEAR are reviewed and a summary of the March/April (1990) run is given. Effects of the October 1989 earthquake on SPEAR and PEP are noted and the characterization and performance of the two hard X-ray beam lines on PEP are summarized. C1 UNIV OREGON,INST THEORET SCI,EUGENE,OR 97403. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720. RP TATCHYN, R (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305, USA. NR 36 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 OCT 10 PY 1991 VL 308 IS 1-2 BP 13 EP 23 DI 10.1016/0168-9002(91)90578-E PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GN153 UT WOS:A1991GN15300004 ER PT J AU TATCHYN, R CREMER, T CSONKA, P AF TATCHYN, R CREMER, T CSONKA, P TI DESIGN CONSIDERATIONS FOR A NEW WEAK-FIELD SOFT-X-RAY UNDULATOR FEL DRIVER FOR PEP SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9TH USSR NATIONAL CONF ON SYNCHROTRON RADIATION UTILIZATION ( SR 90 ) CY JUN 26-29, 1990 CL MOSCOW, USSR SP ACAD SCI USSR, P N LEBEDEV PHYS INST, MOSCOW STATE UNIV, ACAD SCI USSR, SYNCHROTRON RADIAT COMMISS ID FREE-ELECTRON LASER; PARAMETERS AB Design considerations and projected performance parameters for a novel variable-field undulator are reviewed. The design, which has no moving parts, features the absence of permeable or permanent magnet (PM) materials and is capable of generating light of arbitrary polarization with negligible coupling between the vertical and horizontal phase space distributions. The attainable field precision of the (iron-free) electromagnetic structure makes it suitable for high energy (> 4 GeV) FEL or optical klystron (OK) applications in straight sections approaching several hundred meters in length. While non-optimal in the amount of power required for rated operation, the configuration features maximal mechanical simplicity, resulting in a significantly less expensive structure than a conventional PM design. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720. UNIV OREGON,INST THEORET SCI,EUGENE,OR 97403. UNIV OREGON,DEPT PHYS,EUGENE,OR 97403. RP TATCHYN, R (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305, USA. NR 31 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 10 PY 1991 VL 308 IS 1-2 BP 152 EP 164 DI 10.1016/0168-9002(91)90617-Y PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GN153 UT WOS:A1991GN15300043 ER PT J AU JADACH, S RICHTERWAS, E WARD, BFL WAS, Z AF JADACH, S RICHTERWAS, E WARD, BFL WAS, Z TI QED MULTIPHOTON CORRECTIONS TO BHABHA SCATTERING AT LOW ANGLES - MONTE-CARLO SOLUTION SO PHYSICS LETTERS B LA English DT Article ID RADIATIVE-CORRECTIONS; PHOTON CORRECTIONS; NUMBER GENERATORS; HIGH-ENERGIES; ANNIHILATION AB We calculate the QED-corrected integrated cross-section for small-angle Bhabha scattering with kinematical cuts very close to the real experimental cuts at the LEP/SLC experiments - no distinction between electrons and photons is made. We effectively compare up to four independent Monte Carlo calculations and one semi-analytical calculation. The aim of the exercise is to establish precision of the O (alpha) Monte Carlo calculation with the exclusive exponentiation of the Yennie-Frautschi-Suura type. It provides the integrated cross-section for the low-angle Bhabha scattering process (curly theta < 10-degrees), necessary for luminosity measurement, with an overall precision of 0.25%. The corresponding computer program BHLUMI 2.00 is in the form of a stand-alone Monte Carlo event generator. The complete and explicit definition of the multiphoton matrix element is given. Examples of numerical results from Monte Carlo phase space integration are demonstrated and discussed. C1 JAGIELLONIAN UNIV,COMP SCI,PL-30059 KRAKOW,POLAND. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. INST NUCL PHYS,PL-30055 KRAKOW,POLAND. RP JADACH, S (reprint author), CERN,DIV THEORY,CH-1211 GENEVA 23,SWITZERLAND. NR 21 TC 51 Z9 51 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 OCT 10 PY 1991 VL 268 IS 2 BP 253 EP 262 DI 10.1016/0370-2693(91)90813-6 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GM920 UT WOS:A1991GM92000017 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 ANTILOGUS, P APEL, WD APSIMON, RJ ASMAN, B ASTIER, P AUGUSTIN, JE AUGUSTINUS, A BAILLON, P BAMBADE, P BARAO, F BARBIELLINI, G BARDIN, DY BARONCELLI, A BARRING, O BARTL, W BATTAGLIA, M BATES, MJ BAUBILLIER, M BECKS, KH BEESTON, CJ BEGALLI, M BEILLIERE, P BELOKOPYTOV, Y BELTRAN, P BENEDIC, D BENLLOCH, JM BERGGREN, M BERTRAND, D BIAGI, S BIANCHI, F BIBBY, JH BILENKY, MS BILLOIR, P BJARNE, J BLOCH, D BLYTH, S BOGOLUBOV, PN BOLOGNESE, T BONAPART, M BONESINI, M BONIVENTO, W BOOTH, PSL BORATAV, M BORGEAUD, P BORISOV, G 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 CERRITO, L CHARPENTIER, P CHECCHIA, P CHELKOV, GA CHEVALIER, L CHLIAPNIKOV, P CHOROWICZ, V CIRIO, R CLARA, MP COLLINS, P CONTRERAS, JL CONTRI, R COSME, G COUCHOT, F CRAWLEY, HB CRENNELL, D CROSETTI, G CROSLAND, N CROZON, M MAESTRO, JC CZELLAR, S DAGORET, S DAHLJENSEN, E DALMAGNE, B DAM, M DAMGAARD, G DARBO, G DAUBIE, E DAUNCEY, PD DAVENPORT, M DAVID, P DEANGELIS, A DEBEER, M DEBOECK, H DEBOER, W DECLERCQ, C LASO, MDMD DEGROOT, N DELAVAISSIERE, C DELOTTO, B DEMIN, A DEFOIX, C DELIKARIS, D DELORME, S DELPIERRE, P DEMARIA, N DERKAOUI, J DICIACCIO, L DIJKSTRA, H DJAMA, F DOLBEAU, J DONSZELMANN, M DOROBA, K DRACOS, M DREES, J DRIS, M DUFOUR, Y DULINSKI, W DZHELYADIN, R EEK, LO EEROLA, PAM EKELOF, T EKSPONG, G PEISERT, AE ENGEL, JP FASSOULIOTIS, D FENYUK, A ALONSO, MF FERRER, A FILIPPAS, TA FIRESTONE, A FOETH, H FOKITIS, E FOLEGATI, P FONTANELLI, F FORSBACH, H FRANEK, B FRENKIEL, P FRIES, DC FRODESEN, AG FRUHWIRTH, R FULDAQUENZER, F FURNIVAL, K FURSTENAU, H FUSTER, J GAGO, JM GALEAZZI, G GAMBA, D GARCIA, C 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 GROS, MH GROSDIDIER, G GROSSETETE, B GUMENYUK, S GUY, J HAHN, F HAHN, M HAIDER, S HAJDUK, Z HAKANSSON, A HALLGREN, A HAMACHER, K DEMONCHENAULT, GH HARRIS, FJ HECK, BW HERBST, I HERNANDEZ, JJ HERQUET, P HERR, H HIETANEN, I HIGON, E HILKE, HJ HODGSON, SD HOFMOKL, T HOLMES, R HOLMGREN, SO HOLTHUIZEN, D HONORE, PF HOOPER, JE HOULDEN, M HRUBEC, J HULTH, PO HULTQVIST, K HUSSON, D HYAMS, BD IOANNOU, P ISENHOWER, D IVERSEN, PS JACKSON, JN JALOCHA, P JARLSKOG, G JARRY, P JEANMARIE, B JOHANSSON, EK JOHNSON, D JONKER, M JONSSON, L JUILLOT, P KALKANIS, G KALMUS, G KANTARDJIAN, G KAPUSTA, F KATARGIN, A KATSANEVAS, S KATSOUFIS, EC KERANEN, R KESTEMAN, J KHOMENKO, BA KHOVANSKI, NN KING, B KJAER, NJ KLEIN, H KLEMPT, W KLOVNING, A KLUIT, P KOEHNE, JH KOENE, B KOKKINIAS, P KOPF, M KORATZINOS, M KORCYL, K KORYTOV, AV KORZEN, B KOSTUKHIN, V KOURKOUMELIS, C KREUZBERGER, T KROLIKOWSKI, J KRUENERMARQUIS, U KRUPINSKI, W KUCEWICZ, W KURVINEN, K LACASTA, C LAMBROPOULOS, C LAMSA, JW LANCERI, L LAPIN, V LAUGIER, JP LAUHAKANGAS, R LEDER, G LEDROIT, F LEMONNE, J LENZEN, G LEPELTIER, V LETESSIERSELVON, A LIKO, D LIEB, E LILLETHUN, E LINDGREN, J LIPNIACKA, A LIPPI, I LLOSA, R LOERSTAD, B LOKAJICEK, M LOKEN, JG AGUERA, MAL LOPEZFERNANDEZ, A LOS, M LOUKAS, D LOUNIS, A LOZANO, JJ LUCOCK, R LUTZ, P LYONS, L MAEHLUM, G MAILLARD, J MALTEZOS, A MALTEZOS, S MANDL, F MARCO, J MARGONI, M MARIN, JC MARKOU, A MARTI, S MATHIS, L MATORRAS, F MATTEUZZI, C MATTHIAE, G MAZZUCATO, M MCCUBBIN, M MCKAY, R MCNULTY, R MENICHETTI, E MERONI, C MEYER, WT MICHELOTTO, M MITAROFF, WA MITSELMAKHER, GV MJOERNMARK, U MOA, T MOELLER, R MOENIG, K MONGE, MR MORETTINI, P MUELLER, H MULLER, H MURRAY, WJ MYATT, G NARAGHI, F NAUKORZEN, U NAVARRIA, FL NEGRI, P NIELSEN, BS NIJJHAR, B NIKOLAENKO, V OBRAZTSOV, V OLSHEVSKI, AG ORAVA, R OSTANKOV, A OURAOU, A PAIN, R PALKA, H PAPADOPOULOU, T PAPE, L PASSERI, A PEGORARO, M PEREVOZCHIKOV, V PERNICKA, M PERROTTA, A PIERRE, F PIMENTA, M PINGOT, O PINSENT, A POL, ME POLOK, G POROPAT, P PRIVITERA, P PULLIA, A PYYHTIA, J RADOJICIC, D RAGAZZI, S RANGE, WH RATOFF, PN READ, AL REDAELLI, NG REGLER, M REID, D RENTON, PB RESVANIS, LK RICHARD, F RICHARDSON, M RIDKY, J RINAUDO, G RODITI, I ROMERO, A RONCAGLIOLO, I RONCHESE, P RONNQVIST, C ROSENBERG, EI ROSSI, U ROSSO, E ROUDEAU, P ROVELLI, T RUCKSTUHL, W RUHLMANN, V RUIZ, A RYBICKI, K SAARIKKO, H SACQUIN, Y SALT, J SANCHEZ, E SANCHEZ, J SANNINO, M SCHAEFFER, M SCHAEL, S 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 SKJEVLING, G SMADJA, 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, CJ SZCZEKOWSKI, M SZEPTYCKA, M SZYMANSKI, P TABARELLI, T TAVERNIER, S THEODOSIOU, GE TILQUIN, A TIMMERMANS, J TIMOFEEV, VG TKATCHEV, LG TODOROV, T TOET, DZ 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 UEBERSCHAER, B UEBERSCHAER, S ULLALAND, O UVAROV, VA VALENTI, G VALLAZZA, E FERRER, JAV VANAPELDOORN, GW VANDAM, P VANDONINCK, WK VANEIJNDHOVEN, N VANDERVELDE, 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 VOLPONI, S VOULGARIS, G VOUTILAINEN, M VRBA, V WAHLEN, H WALCK, C WALDNER, F WAYNE, M 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 ZEVGOLATAKOS, E ZHANG, G ZIMIN, NI ZITO, M 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 ANTILOGUS, P APEL, WD APSIMON, RJ ASMAN, B ASTIER, P AUGUSTIN, JE AUGUSTINUS, A BAILLON, P BAMBADE, P BARAO, F BARBIELLINI, G BARDIN, DY BARONCELLI, A BARRING, O BARTL, W BATTAGLIA, M BATES, MJ BAUBILLIER, M BECKS, KH BEESTON, CJ BEGALLI, M BEILLIERE, P BELOKOPYTOV, Y BELTRAN, P BENEDIC, D BENLLOCH, JM BERGGREN, M BERTRAND, D BIAGI, S BIANCHI, F BIBBY, JH BILENKY, MS BILLOIR, P BJARNE, J BLOCH, D BLYTH, S BOGOLUBOV, PN BOLOGNESE, T BONAPART, M BONESINI, M BONIVENTO, W BOOTH, PSL BORATAV, M BORGEAUD, P BORISOV, G 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 CERRITO, L CHARPENTIER, P CHECCHIA, P CHELKOV, GA CHEVALIER, L CHLIAPNIKOV, P CHOROWICZ, V CIRIO, R CLARA, MP COLLINS, P CONTRERAS, JL CONTRI, R COSME, G COUCHOT, F CRAWLEY, HB CRENNELL, D CROSETTI, G CROSLAND, N CROZON, M MAESTRO, JC CZELLAR, S DAGORET, S DAHLJENSEN, E DALMAGNE, B DAM, M DAMGAARD, G DARBO, G DAUBIE, E DAUNCEY, PD DAVENPORT, M DAVID, P DEANGELIS, A DEBEER, M DEBOECK, H DEBOER, W DECLERCQ, C LASO, MDMD DEGROOT, N DELAVAISSIERE, C DELOTTO, B DEMIN, A DEFOIX, C DELIKARIS, D DELORME, S DELPIERRE, P DEMARIA, N DERKAOUI, J DICIACCIO, L DIJKSTRA, H DJAMA, F DOLBEAU, J DONSZELMANN, M DOROBA, K DRACOS, M DREES, J DRIS, M DUFOUR, Y DULINSKI, W DZHELYADIN, R EEK, LO EEROLA, PAM EKELOF, T EKSPONG, G PEISERT, AE ENGEL, JP FASSOULIOTIS, D FENYUK, A ALONSO, MF FERRER, A FILIPPAS, TA FIRESTONE, A FOETH, H FOKITIS, E FOLEGATI, P FONTANELLI, F FORSBACH, H FRANEK, B FRENKIEL, P FRIES, DC FRODESEN, AG FRUHWIRTH, R FULDAQUENZER, F FURNIVAL, K FURSTENAU, H FUSTER, J GAGO, JM GALEAZZI, G GAMBA, D GARCIA, C 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 GROS, MH GROSDIDIER, G GROSSETETE, B GUMENYUK, S GUY, J HAHN, F HAHN, M HAIDER, S HAJDUK, Z HAKANSSON, A HALLGREN, A HAMACHER, K DEMONCHENAULT, GH HARRIS, FJ HECK, BW HERBST, I HERNANDEZ, JJ HERQUET, P HERR, H HIETANEN, I HIGON, E HILKE, HJ HODGSON, SD HOFMOKL, T HOLMES, R HOLMGREN, SO HOLTHUIZEN, D HONORE, PF HOOPER, JE HOULDEN, M HRUBEC, J HULTH, PO HULTQVIST, K HUSSON, D HYAMS, BD IOANNOU, P ISENHOWER, D IVERSEN, PS JACKSON, JN JALOCHA, P JARLSKOG, G JARRY, P JEANMARIE, B JOHANSSON, EK JOHNSON, D JONKER, M JONSSON, L JUILLOT, P KALKANIS, G KALMUS, G KANTARDJIAN, G KAPUSTA, F KATARGIN, A KATSANEVAS, S KATSOUFIS, EC KERANEN, R KESTEMAN, J KHOMENKO, BA KHOVANSKI, NN KING, B KJAER, NJ KLEIN, H KLEMPT, W KLOVNING, A KLUIT, P KOEHNE, JH KOENE, B KOKKINIAS, P KOPF, M KORATZINOS, M KORCYL, K KORYTOV, AV KORZEN, B KOSTUKHIN, V KOURKOUMELIS, C KREUZBERGER, T KROLIKOWSKI, J KRUENERMARQUIS, U KRUPINSKI, W KUCEWICZ, W KURVINEN, K LACASTA, C LAMBROPOULOS, C LAMSA, JW LANCERI, L LAPIN, V LAUGIER, JP LAUHAKANGAS, R LEDER, G LEDROIT, F LEMONNE, J LENZEN, G LEPELTIER, V LETESSIERSELVON, A LIKO, D LIEB, E LILLETHUN, E LINDGREN, J LIPNIACKA, A LIPPI, I LLOSA, R LOERSTAD, B LOKAJICEK, M LOKEN, JG AGUERA, MAL LOPEZFERNANDEZ, A LOS, M LOUKAS, D LOUNIS, A LOZANO, JJ LUCOCK, R LUTZ, P LYONS, L MAEHLUM, G MAILLARD, J MALTEZOS, A MALTEZOS, S MANDL, F MARCO, J MARGONI, M MARIN, JC MARKOU, A MARTI, S MATHIS, L MATORRAS, F MATTEUZZI, C MATTHIAE, G MAZZUCATO, M MCCUBBIN, M MCKAY, R MCNULTY, R MENICHETTI, E MERONI, C MEYER, WT MICHELOTTO, M MITAROFF, WA MITSELMAKHER, GV MJOERNMARK, U MOA, T MOELLER, R MOENIG, K MONGE, MR MORETTINI, P MUELLER, H MULLER, H MURRAY, WJ MYATT, G NARAGHI, F NAUKORZEN, U NAVARRIA, FL NEGRI, P NIELSEN, BS NIJJHAR, B NIKOLAENKO, V OBRAZTSOV, V OLSHEVSKI, AG ORAVA, R OSTANKOV, A OURAOU, A PAIN, R PALKA, H PAPADOPOULOU, T PAPE, L PASSERI, A PEGORARO, M PEREVOZCHIKOV, V PERNICKA, M PERROTTA, A PIERRE, F PIMENTA, M PINGOT, O PINSENT, A POL, ME POLOK, G POROPAT, P PRIVITERA, P PULLIA, A PYYHTIA, J RADOJICIC, D RAGAZZI, S RANGE, WH RATOFF, PN READ, AL REDAELLI, NG REGLER, M REID, D RENTON, PB RESVANIS, LK RICHARD, F RICHARDSON, M RIDKY, J RINAUDO, G RODITI, I ROMERO, A RONCAGLIOLO, I RONCHESE, P RONNQVIST, C ROSENBERG, EI ROSSI, U ROSSO, E ROUDEAU, P ROVELLI, T RUCKSTUHL, W RUHLMANN, V RUIZ, A RYBICKI, K SAARIKKO, H SACQUIN, Y SALT, J SANCHEZ, E SANCHEZ, J SANNINO, M SCHAEFFER, M SCHAEL, S 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 SKJEVLING, G SMADJA, 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, CJ SZCZEKOWSKI, M SZEPTYCKA, M SZYMANSKI, P TABARELLI, T TAVERNIER, S THEODOSIOU, GE TILQUIN, A TIMMERMANS, J TIMOFEEV, VG TKATCHEV, LG TODOROV, T TOET, DZ 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 UEBERSCHAER, B UEBERSCHAER, S ULLALAND, O UVAROV, VA VALENTI, G VALLAZZA, E FERRER, JAV VANAPELDOORN, GW VANDAM, P VANDONINCK, WK VANEIJNDHOVEN, N VANDERVELDE, 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 VOLPONI, S VOULGARIS, G VOUTILAINEN, M VRBA, V WAHLEN, H WALCK, C WALDNER, F WAYNE, M 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 ZEVGOLATAKOS, E ZHANG, G ZIMIN, NI ZITO, M ZITOUN, R FUNCHAL, RZ ZUMERLE, G ZUNIGA, J TI THE REACTION E+E--] GAMMA-GAMMA(GAMMA) AT Z0 ENERGIES SO PHYSICS LETTERS B LA English DT Article ID Z->PI-0-GAMMA; DECAYS AB The total and differential cross-sections for the reaction e+e- --> gamma-gamma(gamma) are measured at centre of mass energies around 91 GeV using an integrated luminosity of 4.7 pb-1. The agreement with the QED prediction is good. Consequently there is no evidence for non-standard channels which would have the same experimental signature. The lower limits on the QED cutoff parameters are LAMBDA+ > 113 GeV and LAMBDA- > 95 GeV. An upper limit on the effective coupling between a possible excited electron and the gamma is derived. At 95% confidence level the branching ratios for Z0 decay into pi-0-gamma, eta-gamma and gamma-gamma-gamma are below 1.5 x 10(-4), 2.8 x 10(-4) and 1.4 x 10(-4) respectively. C1 CERN,CH-1211 GENEVA 23,SWITZERLAND. UNIV LUND,S-22362 LUND,SWEDEN. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV LYON 1,F-69622 VILLEURBANNE,FRANCE. UNIV WARSAW,PL-00681 WARSAW,POLAND. UNIV KARLSRUHE,INST EXPTL KERNPHYS,W-7500 KARLSRUHE 1,GERMANY. UNIV STOCKHOLM,INST PHYS,S-11346 STOCKHOLM,SWEDEN. UNIV PARIS 06,PHYS NUCL & HAUTES ENERGIES LAB,F-75230 PARIS 05,FRANCE. UNIV MILAN,DIPARTMENTO FIS,I-20133 MILAN,ITALY. AUSTRIAN ACAD SCI,INST HOCHENERGIEPHYS,A-1050 VIENNA,AUSTRIA. CENS,DEPT PHYS & PARTICULES ELEMENTAIRES,F-91191 GIF SUR YVETTE,FRANCE. JOINT INST NUCL RES,MOSCOW 101000,USSR. UNIV VALENCIA,CSIC,CTR MIXTO,INST FIS CORPUSCULAR,E-46100 BURJASSOT,SPAIN. UNIV BERGEN,DEPT PHYS,N-5007 BERGEN,NORWAY. UNIV ATHENS,PHYS LAB,GR-10680 ATHENS,GREECE. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IST NAZL FIS NUCL,PADUA,ITALY. UNIV INSTELLING ANTWERP,B-2610 WILRIJK,BELGIUM. NATL INST NUCL PHYS,ROME,ITALY. UNIV OXFORD,NUCL PHYS LAB,OXFORD OX1 3RH,ENGLAND. UNIV GENOA,DIPARTIMENTO FIS,I-16146 GENOA,ITALY. IST NAZL FIS NUCL,TURIN,ITALY. UNIV TURIN,DIPARTIMENTO FIS SPERIMENTALE,I-10125 TURIN,ITALY. UNIV UPPSALA,DEPT RADIAT SCI,S-75121 UPPSALA,SWEDEN. IST NAZL FIS NUCL,BOLOGNA,ITALY. UNIV HELSINKI,HIGH ENERGY PHYS RES INST,SF-00170 HELSINKI 17,FINLAND. UNIV OSLO,DEPT PHYS,N-1000 OSLO 3,NORWAY. UNIV SANTANDER,FAC CIENCIAS,E-39005 SANTANDER,SPAIN. UNIV ROME 2,DIPARTIMENTO FIS,I-00173 ROME,ITALY. UNIV COMPLUTENSE MADRID,DEPT FIS ATOM MOLEC & NUCL,E-28040 MADRID,SPAIN. NIELS BOHR INST,DK-2100 COPENHAGEN 0,DENMARK. INST NUCL STUDIES,PL-00681 WARSAW,POLAND. NATL TECH UNIV ATHENS,DEPT PHYS,GR-15773 ATHENS,GREECE. INST NUCL PHYS,HIGH ENERGY PHYS LAB,PL-30055 KRAKOW 30,POLAND. UNIV AIX MARSEILLE 2,FAC SCI LUMINY,F-13288 MARSEILLE 09,FRANCE. UNIV BOLOGNA,DIPARTMENTO FIS,I-40126 BOLOGNA,ITALY. UNIV PARIS 07,F-75230 PARIS 05,FRANCE. UNIV PARIS 11,ACCELERATEUR LINEAIRE LAB,F-91405 ORSAY,FRANCE. UNIV TRIESTE,DIPARTMENTO FIS,I-34127 TRIESTE,ITALY. IST NAZL FIS NUCL,TRIESTE,ITALY. UNIV UDINE,IST FIS,I-33100 UDINE,ITALY. IST SUPER SANITA,IST NAZL FIS NUCL,I-00161 ROME,ITALY. NATL INST NUCL PHYS,MILAN,ITALY. UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH PHYS,W-5600 WUPPERTAL 1,GERMANY. COLL FRANCE,PHYS CORPUSCULAIRE LAB,F-75231 PARIS 05,FRANCE. SERPUKHOV HIGH ENERGY PHYS INST,PROTVINO 142284,USSR. DEMOCRITOS NUCL RES CTR,INST NUCL PHYS,GR-15310 ATHENS,GREECE. UNIV LIVERPOOL,DEPT PHYS,LIVERPOOL L69 3BX,ENGLAND. UNIV PADUA,DIPARTMENTO FIS,I-35131 PADUA,ITALY. NIKHEF H,1009 DB AMSTERDAM,NETHERLANDS. FAC SCI OUJDA,DEPT PHYS,OUJDA,MOROCCO. VRIJE UNIV BRUSSELS,UNIV LIBRE BRUSSELS,IIHE,B-1050 BRUSSELS,BELGIUM. UNIV ETAT MONS,FAC SCI,SERV PHYS PARTICULES ELEMENTAIRES,B-7000 MONS,BELGIUM. CTR RECH NUCL,GRP DELPHI,DIV HAUTES ENERGIES,F-67037 STRASBOURG,FRANCE. CTR RECH NUCL,LEPSI,F-67037 STRASBOURG,FRANCE. RP ABREU, P (reprint author), LIP,AV ELIAS GARCIA 14-1E,P-1000 LISBON,PORTUGAL. RI Monge, Maria Roberta/G-9127-2012; Ridky, Jan/H-6184-2014; Zukanovich Funchal, Renata/C-5829-2013; Contreras Gonzalez, Jose Luis/K-7255-2014; Pimenta, Mario/M-1741-2013; Gomez Cadenas, Juan Jose/L-2003-2014; Ragazzi, Stefano/D-2463-2009; Roditi, Itzhak/O-7448-2014; Zuniga, Juan/P-4385-2014; Michelotto, Michele/A-9571-2013; Matorras, Francisco/I-4983-2015; Ferrer, Antonio/H-2942-2015; de Groot, Nicolo/A-2675-2009; Vaz, Pedro/K-2464-2013; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Giacomelli, Paolo/B-8076-2009; Fruhwirth, Rudolf/H-2529-2012; Dracos, Marcos/K-2335-2012; Hallgren, Allan/A-8963-2013; Botner, Olga/A-9110-2013; Zalewski, Piotr/H-7335-2013; Marti-Garcia, Salvador/F-3085-2011; Varela, Joao/K-4829-2016; Rovelli, Tiziano/K-4432-2015; Fernandez-Alonso, Mercedes/F-2557-2016; Lozano-Bahilo, Julio/F-4881-2016; Olshevskiy, Alexander/I-1580-2016; Hernandez-Rey, Juan Jose/N-5955-2014; Abreu, Pedro/L-2220-2014; Barao, Fernando/O-2357-2016; Zaitsev, Alexandre/B-8989-2017 OI Monge, Maria Roberta/0000-0003-1633-3195; Ridky, Jan/0000-0001-6697-1393; Zukanovich Funchal, Renata/0000-0001-6749-0022; Contreras Gonzalez, Jose Luis/0000-0001-7282-2394; Pimenta, Mario/0000-0002-2590-0908; Gomez Cadenas, Juan Jose/0000-0002-8224-7714; Ragazzi, Stefano/0000-0001-8219-2074; Roditi, Itzhak/0000-0003-2363-5626; Zuniga, Juan/0000-0002-1041-6451; Michelotto, Michele/0000-0001-6644-987X; Matorras, Francisco/0000-0003-4295-5668; Ferrer, Antonio/0000-0003-0532-711X; Vaz, Pedro/0000-0002-7186-2359; Ruiz, Alberto/0000-0002-3639-0368; Shellard, Ronald/0000-0002-2983-1815; Dracos, Marcos/0000-0003-0514-193X; Matteuzzi, Clara/0000-0002-4047-4521; DE MIN, ALBERTO/0000-0002-8130-9389; Demaria, Natale/0000-0003-0743-9465; 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; Rovelli, Tiziano/0000-0002-9746-4842; Fernandez-Alonso, Mercedes/0000-0002-1311-5275; Lozano-Bahilo, Julio/0000-0003-0613-140X; Olshevskiy, Alexander/0000-0002-8902-1793; Hernandez-Rey, Juan Jose/0000-0002-1527-7200; Abreu, Pedro/0000-0002-9973-7314; Barao, Fernando/0000-0002-8346-9941; Zaitsev, Alexandre/0000-0002-4961-8368 NR 21 TC 25 Z9 25 U1 0 U2 8 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 OCT 10 PY 1991 VL 268 IS 2 BP 296 EP 304 DI 10.1016/0370-2693(91)90819-C PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GM920 UT WOS:A1991GM92000023 ER PT J AU BORG, SG DEPAOLO, DJ AF BORG, SG DEPAOLO, DJ TI A TECTONIC MODEL OF THE ANTARCTIC GONDWANA MARGIN WITH IMPLICATIONS FOR SOUTHEASTERN AUSTRALIA - ISOTOPIC AND GEOCHEMICAL EVIDENCE SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT SYMP AT THE 28TH INTERNATIONAL GEOLOGICAL CONGRESS : ACCRETIONARY TECTONICS AND COMPOSITE CONTINENTS CY JUL, 1989 CL WASHINGTON, DC ID NORTHERN VICTORIA-LAND; TRANSANTARCTIC MOUNTAINS; GRANITIC-ROCKS; GLACIER AREA; NEODYMIUM; HISTORY AB Geochemical studies of Paleozoic granites in northern Victoria Land (NVL) and the central Transantarctic Mountains (CTM) are integrated with structural and lithologic studies into a model for the tectonic development of the Antarctic-southeast Australian Gondwana margin in late Precambrian-middle Paleozoic time. Isotopic data (Nd, Sr, O) are used to define crustal basement age boundaries and subduction polarity and thus help identify suspect terranes. In the CTM, three basement age-blocks are recognized: The outboard two provinces are inferred to be allochthonous, with accretion to the Gondwana margin occurring between almost-equal-to 750 and almost-equal-to 500 Ma. This tectonic scenario is inferred to apply also to NVL and southeastern Australia (SEA). In the CTM and NVL, chemical and isotopic polarity of ca. 500 Ma granitoids indicate a cratonward-dipping subduction zone. In NVL, terranes outboard of the belt of ca. 500 Ma granites contain Devonian (ca. 400 Ma) I-type granites with chemical and isotopic polarity opposed to that of the ca. 500 Ma granites. In the furthest outboard position, S-type granites emplaced at ca. 600 and 525 Ma occur with ca. 400 Ma granites and indicate the presence of early Proterozoic basement. This NVL terrane collage is allochthonous; it was assembled, intruded by Devonian granites, and then tectonically accreted to the Gondwana margin between latest Devonian and Permian time. Terrane correlations with SEA imply that much of the latter was accreted to the Gondwana margin after Devonian time. Other fragments of this allochthonous continental collage are probably in Marie Byrd Land (West Antarctica) and New Zealand (including the Campbell Plateau). C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP BORG, SG (reprint author), UNIV CALIF BERKELEY,BERKELEY CTR ISOTOPE GEOCHEM,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720, USA. NR 48 TC 98 Z9 99 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD OCT 10 PY 1991 VL 196 IS 3-4 BP 339 EP 358 DI 10.1016/0040-1951(91)90329-Q PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GP011 UT WOS:A1991GP01100006 ER PT J AU CRAMER, SP DEGROOT, FMF MA, Y CHEN, CT SETTE, F KIPKE, CA EICHHORN, DM CHAN, MK ARMSTRONG, WH LIBBY, E CHRISTOU, G BROOKER, S MCKEE, V MULLINS, OC FUGGLE, JC AF CRAMER, SP DEGROOT, FMF MA, Y CHEN, CT SETTE, F KIPKE, CA EICHHORN, DM CHAN, MK ARMSTRONG, WH LIBBY, E CHRISTOU, G BROOKER, S MCKEE, V MULLINS, OC FUGGLE, JC TI LIGAND-FIELD STRENGTHS AND OXIDATION-STATES FROM MANGANESE L-EDGE SPECTROSCOPY SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID X-RAY-ABSORPTION; COMPLEX; TRANSITION; SPECTRA AB L2,3 X-ray absorption spectra have been recorded for Mn(II), Mn(III), and Mn(IV) samples with a variety of ligands. For high-spin Mn(II) complexes, a systematic variation in spectra is observed as the ligand field is increased. A dramatically different spectrum is observed for Mn(CN)6(4-), consistent with the presence of a low-spin complex. Progressing in oxidation state from Mn(II) to Mn(III) through Mn(IV) complexes, the primary peak position shifts first 1.5-2 eV and then 1-2 eV to higher energy, and the ratio of L3 to L2 intensity decreases. The spectra have been quantitatively simulated with an atomic multiplet program with an octahedral crystal field superimposed. The high resolution, strong sensitivity to chemical environment and amenability to quantitative spectral shape analysis indicate that L-edges of the first transition series metals are a potentially useful probe for bioinorganic studies. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. INDIANA UNIV,DEPT CHEM,BLOOMINGTON,IN 47405. CATHOLIC UNIV NIJMEGEN,MAT RES INST,6525 ED NIJMEGEN,NETHERLANDS. SCHLUMBERGER DOLL RES CTR,RIDGEFIELD,CT 06877. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CANTERBURY,DEPT CHEM,CHRISTCHURCH 1,NEW ZEALAND. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL CHEM,BERKELEY,CA 94720. RP CRAMER, SP (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616, USA. RI de Groot, Frank/A-1918-2009; Brooker, Sally/C-3440-2016; Christou, George /A-3072-2014; OI Brooker, Sally/0000-0002-5878-8238; McKee, Vickie/0000-0002-7780-5814; Eichhorn, David/0000-0002-9780-4149 NR 35 TC 136 Z9 136 U1 4 U2 36 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 OCT 9 PY 1991 VL 113 IS 21 BP 7937 EP 7940 DI 10.1021/ja00021a018 PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA GJ647 UT WOS:A1991GJ64700018 ER PT J AU DING, JP STEINER, T ZABEL, V HINGERTY, BE MASON, SA SAENGER, W AF DING, JP STEINER, T ZABEL, V HINGERTY, BE MASON, SA SAENGER, W TI TOPOGRAPHY OF CYCLODEXTRIN INCLUSION COMPLEXES .28. NEUTRON-DIFFRACTION STUDY OF THE HYDROGEN-BONDING IN PARTIALLY DEUTERATED GAMMA-CYCLODEXTRIN.15.7D2O AT T = 110-K SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID VITAMIN-B12 COENZYME CRYSTALS; MOLECULAR-STRUCTURE; WATER-STRUCTURE; SYSTEM; UNDECAHYDRATE; HEXAHYDRATE AB A single-crystal neutron diffraction study of partially deuterated gamma-cyclodextrin (gamma-CD) hydrate, (C6D3H7O5)8.15.7D2O, was carried out at T = 110 K. The crystal is monoclinic, space group P2(1), with cell dimensions a = 16.899 (7) angstrom, b = 10.891 (5) angstrom, c = 20.226 (6) angstrom, beta = 105.06 (2) degrees, Z = 2, and V = 3595 (2) angstrom 3. A total of 10688 reflections were collected with lambda = 1.3196 angstrom on an area detector to the nominal resolution of 0.92 angstrom, yielding 4906 unique reflections with an R(merge) = 0.064 on F2. All H and D atoms for the cyclodextrin molecule and most of the D atoms for the water molecules were located, and the structure was refined to an R factor of 0.093 for 4538 observed reflections (F2 greater-than-or-equal-to sigma(F2)). In the crystal structure, the gamma-CD molecules are arranged in a herringbone pattern forming a cage-type packing. A narrow intermolecular interstitial channel, which is filled with water molecules, runs along the crystallographic b axis at a approximately 1/2 and c approximately 0. Compared with the beta-CD hydrate, which crystallizes in a similar packing arrangement, the cavities of the gamma-CD molecules are not as completely closed at the narrow O(6) hydroxyl group end by adjacent molecules and are connected with the interstitial channel. All glucose residues are in the usual 4C1 chair conformation with a relatively strong distortion of glucose residue 1 (theta-2 = 14.5-degrees). Glucose residue 8, which closes the cavity of a symmetry-related gamma-CD molecule at the wider O(2),O(3) end, and even slightly intrudes into it, is somewhat disordered as a whole. The 15.7 water molecules in the asymmetric unit are distributed over 25 positions. A total of 8.8 water molecules are located in the hydrophobic gamma-CD cavity; they are all positionally disordered and distributed over 17 positions with occupation factors in the range 0.31-0.95. The hydrogen-bond network in the cavity is very complicated due to the severe disorder of the water molecules and could not be reliably assigned in any detail. One water molecule acts as a bridge connection and has hydrogen bonds both to water molecules enclosed in the gamma-CD cavity and to water molecules in the intermolecular interstice, and one water molecule donates a hydrogen bond to glycosidic O(4) of the cavity wall. There are 6.9 water molecules located over 8 sites in the intermolecular interstitial channel, 5 of them are fully occupied, the others are partially occupied, with occupation factors in the range 0.13-0.88. The water molecules in the interstice are better ordered than those in the gamma-CD cavity and have a clearer hydrogen-bonding scheme. One water molecule, which is 2-fold disordered, is isolated from all other water molecule sites and forms hydrogen bonds only to hydroxyl groups of gamma-CD molecules; the others have hydrogen bonds to adjacent water molecules and/or to gamma-CD hydroxyl groups or donate hydrogen bonds to ring oxygen atoms O(5). Of 71 symmetry-independent hydrogen bonds in this crystal structure, 25 (= 35%) are of the three-center type, if a 2.8-angstrom cutoff criterion is used. All O(2) and O(3) hydroxyl groups of neighboring glucose units form interresidue, intramolecular hydrogen bonds, which are major components of unsymmetrical three-center hydrogen bonds donating relatively strong intramolecular components to the corresponding glycosidic O(4) atoms. One primary hydroxyl group donates a minor intraglucose hydrogen-bonding component to O(5) of the same residue; O(5) and O(6) of two glucose accept chelated three-center hydrogen bonds, and in two glucose residues, O(2) and O(3) of the same glucose accept three-center hydrogen bonds. All O-D...O hydrogen bonds are interconnected to form an infinite spatial network, with infinite chains, cycles, and finite chains as motifs, reminiscent of alpha-CD and beta-CD hydrates. Homodromic arrangements of hydrogen bonds dominate in the network and indicate the strong influence of the cooperative effect. C1 FREE UNIV BERLIN,INST KRISTALLOG,TAKUSTR 6,W-1000 BERLIN 33,GERMANY. UNIV TENNESSEE,GRAD SCH BIOMED SCI,KNOXVILLE,TN 37996. INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831. RI mason, sax /E-6738-2011 NR 36 TC 39 Z9 40 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD OCT 9 PY 1991 VL 113 IS 21 BP 8081 EP 8089 DI 10.1021/ja00021a039 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA GJ647 UT WOS:A1991GJ64700039 ER PT J AU PRESTON, C SEIBERT, M AF PRESTON, C SEIBERT, M TI THE CARBOXYL MODIFIER 1-ETHYL-3-[3-(DIMETHYLAMINO)PROPYL]CARBODIIMIDE (EDC) INHIBITS HALF OF THE HIGH-AFFINITY MN-BINDING SITE IN PHOTOSYSTEM-II MEMBRANE-FRAGMENTS SO BIOCHEMISTRY LA English DT Article ID PHOTOSYNTHETIC OXYGEN EVOLUTION; WATER-OXIDIZING COMPLEX; CARBODIIMIDE REACTION; FUNCTIONAL MANGANESE; EXTRINSIC PROTEINS; ELECTRON-TRANSFER; EVOLVING COMPLEX; STATE; SPECTROSCOPY; HISTIDINE AB The diphenylcarbazide(DPC)/Mn2+ assay [Hsu, B.-D., Lee, J.-Y., & Pan, R.-L. (1987) Biochim. Biophys. Acta 890, 89-96] was used to assess the amount of the high-affinity Mn-binding site in manganese-depleted photosystem II (PS II) membrane fragments from spinach and Scenedesmus obliquus. The assay mechanism at high DPC concentration was shown to involve noncompetitive inhibition of only half of the control level of DPC donation to PS II by micromolar concentrations of Mn at pH 6.5 (i.e., one of two DPC donation sites is inhibited). At low DPC concentration both DPC and Mn2+ donate to PS II additively. Treatment with the carboxyl amino acid modifier 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC) inhibited half of the high-affinity Mn-binding site in spinach and Scenedesmus WT PS II membranes and all of the available site in Scenedesmus LF-1 mutant PS II membranes. A similar EDC concentration dependence was observed in all cases. Addition of 2 mM MnCl2 to the 10 mM EDC modification buffer provided complete protection for the Mn-binding site from modification. This protection was specific for Mn2+; six other divalent cations were ineffective. We conclude that EDC modifies that half of the high-affinity Mn-binding site that is insensitive to the histidine modifier diethyl pyrocarbonate (DEPC) [Seibert, M., Tamura, N., & Inoue, Y. (1989) Biochim. Biophys. Acta 974, 185-191] and directly affects ligands that bind Mn. The effects of EDC and DEPC that influence the high-affinity site are mutually exclusive and are specific to the lumenal side of the PS II membrane. Removal of the two more loosely bound of the four functional Mn from PS II membranes uncovers that part of the high-affinity site associated with carboxyl but not histidyl residues. We suggest that carboxyl residues on reaction center proteins are associated with half of the high-affinity Mn-binding site in PS II and are involved along with histidine residues in binding Mn functional in the O2-evolving process. C1 SOLAR ENERGY RES INST,PHOTOCONVERS RES BRANCH,GOLDEN,CO 80401. NR 53 TC 50 Z9 51 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 OCT 8 PY 1991 VL 30 IS 40 BP 9615 EP 9624 DI 10.1021/bi00104a008 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GJ473 UT WOS:A1991GJ47300008 PM 1911747 ER PT J AU PRESTON, C SEIBERT, M AF PRESTON, C SEIBERT, M TI PROTEASE TREATMENTS OF PHOTOSYSTEM-II MEMBRANE-FRAGMENTS REVEAL THAT THERE ARE 4 SEPARATE HIGH-AFFINITY MN-BINDING SITES SO BIOCHEMISTRY LA English DT Article ID PHOTOSYNTHETIC OXYGEN EVOLUTION; CHLOROPLAST CYTOCHROME B-559; WATER-OXIDIZING COMPLEX; THYLAKOID MEMBRANE; TRANSMEMBRANE ORIENTATION; RHODOPSEUDOMONAS-VIRIDIS; FUNCTIONAL MANGANESE; EVOLVING COMPLEX; D1 POLYPEPTIDE; ELECTRON-DONOR AB The "high-affinity Mn-binding site" in Mn-depleted photosystem II (PS II) membrane fragments isolated from Scenedesmus obliquus was examined by using the diphenylcarbazide (DPC)/Mn2+ non-competitive inhibition assay [Preston, C., & Seibert, M. (1991) Biochemistry (preceding paper in this issue)]. Different proteases were used to degrade lumenal surface protein segments from these PS II membranes, and a total of four independent high-affinity Mn-binding sites (ligands) were identified. Carboxypeptidase A, subtilisin, and Staphylococcus aureus V8 protease each degrade one of two high-affinity Mn-binding sites sensitive to the histidine chemical modifier diethyl pyrocarbonate (DEPC). However, sequential treatment experiments indicate that subtilisin degrades a DEPC-sensitive Mn-binding site that is different from the one degraded by the other two proteases. Trypsin also was found to degrade one of the DEPC-sensitive Mn-binding sites (that degraded by carboxypeptidase A and V8 protease). In addition, trypsin degrades one of two 1-ethyl-3-[(3-dimethylamino)propyl]carbodiimide (EDC) sensitive Mn-binding sites, but only in the absence of the 30-kDa extrinsic protein. Thus, the 30-kDa extrinsic protein associated with O2 evolution appears to protect the EDC-sensitive binding site from trypsin degradation. No protease has yet been identified that will degrade the trypsin-insensitive EDC-sensitive Mn-binding site. Under the conditions of the assay (high DPC concentration), more than three Mn per reaction center were found bound to the membrane with a K(M) of about 0.4-mu-M, as determined by direct metal analysis. This is consistent with the idea that each of the four high-affinity sites binds (or provides a ligand for) one of four Mn. These four high-affinity Mn-binding sites may correspond to the four sites formed, albeit sequentially, in the normal photoactivation process. We provide evidence that a histidine residue (His 337) on D1 is a prime candidate for one of the high-affinity Mn-binding sites and suggest that it also provides a nitrogen ligand for binding functional Mn. Finally, an alternative explanation of our data might be that the four high-affinity sites represent four ligands binding a single Mn, and ligands to other membrane bound Mn are not detectable by the DPC/Mn2+ assay. C1 SOLAR ENERGY RES INST,PHOTOCONVERS RES BRANCH,GOLDEN,CO 80401. NR 55 TC 39 Z9 39 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD OCT 8 PY 1991 VL 30 IS 40 BP 9625 EP 9633 DI 10.1021/bi00104a009 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GJ473 UT WOS:A1991GJ47300009 PM 1911748 ER PT J AU HROMAS, R COLLINS, S RASKIND, W DEAVEN, L KAUSHANSKY, K AF HROMAS, R COLLINS, S RASKIND, W DEAVEN, L KAUSHANSKY, K TI HEM-1, A POTENTIAL MEMBRANE-PROTEIN, WITH EXPRESSION RESTRICTED TO BLOOD-CELLS SO BIOCHIMICA ET BIOPHYSICA ACTA LA English DT Article DE HEMATOPOIESIS; MEMBRANE PROTEIN; PHOSPHORYLATION SITE; CHROMOSOMAL TRANSLOCATION ID SEQUENCES; LEUKEMIA; LOCALIZATION; CHROMOSOMES; SITE AB Overlapping cDNAs 3.8 kb in length containing a long open reading frame were obtained that hybridized exclusively to transcripts from hematopoietic cells. Sequence analysis found eight potential membrane domains and two possible cAMP/cGMP phosphorylation sites. This sequence exhibited no homologies with the EMBL/Genbank nucleic acid, SwissProt or GenPept amino acid data bases. The gene is located at 12q13.1, a region of occasional translocations in hematopoietic neoplasia and a rare folic acid fragile site, Fra 12A. C1 FRED HUTCHINSON CANC RES CTR,DEPT MOLEC MED,SEATTLE,WA 98104. UNIV WASHINGTON,SCH MED,DEPT MED,SEATTLE,WA 98195. UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,LOS ALAMOS,NM 87544. RP HROMAS, R (reprint author), INDIANA UNIV,MED CTR,DEPT MED IB-442,975 W WALNUT ST,INDIANAPOLIS,IN 46202, USA. NR 19 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-3002 J9 BIOCHIM BIOPHYS ACTA PD OCT 8 PY 1991 VL 1090 IS 2 BP 241 EP 244 DI 10.1016/0167-4781(91)90109-Y PG 4 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GM738 UT WOS:A1991GM73800015 PM 1932118 ER PT J AU ABRAHAM, MM BLEANEY, B HILL, RW LEASK, MJM WARD, RCC WELLS, MR AF ABRAHAM, MM BLEANEY, B HILL, RW LEASK, MJM WARD, RCC WELLS, MR TI THERMAL AND MAGNETIC-PROPERTIES OF BARIUM HOLMIUM FLUORIDE, BAHO2F8 SO PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID TRIFLUORIDE; HOF3 AB Single crystals of barium holmium fluoride, BaHo2F8, have been grown by the Czochralski technique, and the monoclinic crystal structure has been confirmed by using X-ray diffraction. The trivalent holmium ion Ho3+, 4f10, 5I8, has a single stable isotope Ho-165, with I = 7/2. The crystalline electric field at the lanthanide site has low symmetry, and previous measurements on the dilute compound Ba(Y0.99Ho0.01)2F8 have shown that the ground state of the holmium ion is a non-Kramers doublet with a purely Ising-like g value. In the present work, the stoichiometric compound BaHo2F8 has been studied by optical spectroscopy, together with measurements of the heat capacity, magnetic susceptibility and magnetic moment. The results show that BaHo2F8 enters an antiferromagnetically ordered state below T(N) = 1.76 K. The principal direction of the holmium moments is the crystallographic a-axis, for which group theoretical considerations limit the possibilities for antiferromagnetic order to their configurations. In the optical absorption spectrum between 4.2 K and T(N), shifts in the spectral lines of the holmium ion indicate the presence of short-range magnetic order. This is implied also by the fact that some 40% of the magnetic entropy is contained in the heat capacity at temperatures above T(N). Purely magnetic dipolar interactions would give an ordering temperature of 0.1 K, much less than the observed value of T(N). Dipolar interaction therefore plays only a minor role in the magnetic behaviour; antiferromagnetic exchange interaction is dominant. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP ABRAHAM, MM (reprint author), UNIV OXFORD,CLARENDON LAB,PARKS RD,OXFORD,ENGLAND. NR 12 TC 6 Z9 6 U1 1 U2 1 PU ROYAL SOC LONDON PI LONDON PA 6 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5AG SN 1364-5021 J9 P ROY SOC LOND A MAT JI Proc. R. Soc. London Ser. A-Math. Phys. Eng. Sci. PD OCT 8 PY 1991 VL 435 IS 1893 BP 159 EP 167 DI 10.1098/rspa.1991.0135 PG 9 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GL177 UT WOS:A1991GL17700009 ER PT J AU HOINKIS, M WEBER, ER LANDSTRASS, MI PLANO, MA HAN, S KANIA, DR AF HOINKIS, M WEBER, ER LANDSTRASS, MI PLANO, MA HAN, S KANIA, DR TI PARAMAGNETIC NITROGEN IN CHEMICAL VAPOR-DEPOSITION DIAMOND THIN-FILMS SO APPLIED PHYSICS LETTERS LA English DT Article AB Electron-paramagnetic-resonance (EPR) studies demonstrate the presence of nitrogen point defects in microwave-assisted chemical vapor deposition (CVD) diamond thin films. Polycrystalline powder pattern EPR spectra are interpreted with g = 2.0023, A parallel-to = 114.0 MHz, and A perpendicular-to = 81.3 MHz. These spin parameters are identical to those of nitrogen in single crystal natural diamonds. Quantitative EPR and secondary ion-mass spectrometry (SIMS) results of CVD diamond thin films suggest that nitrogen point defect formation is favored over aggregate nitrogen formation. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. CRYSTALLUME,MENLO PK,CA 94025. RP HOINKIS, M (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 12 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 7 PY 1991 VL 59 IS 15 BP 1870 EP 1872 DI 10.1063/1.106172 PG 3 WC Physics, Applied SC Physics GA GJ107 UT WOS:A1991GJ10700021 ER PT J AU CHAN, CT HO, KM SOUKOULIS, CM AF CHAN, CT HO, KM SOUKOULIS, CM TI PHOTONIC BAND-GAPS IN EXPERIMENTALLY REALIZABLE PERIODIC DIELECTRIC STRUCTURES SO EUROPHYSICS LETTERS LA English DT Article DE CLASSICAL ELECTROMAGNETISM; PROPAGATION AND TRANSMISSION IN INHOMOGENEOUS MEDIA ID SPONTANEOUS EMISSION; WAVE-PROPAGATION; LOCALIZATION AB By solving Maxwell's equations for the propagation of electromagnetic waves in periodic dielectric structures (with dielectric constant epsilon-b in a uniform background epsilon-a), we found that several classes of periodic dielectric structures possess full photonic gaps, as in the case of dielectric spheres arranged in the diamond structure. These new structures have the additional advantage that they can be easily fabricated experimentally. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,DEPT PHYS,AMES,IA 50011. RP CHAN, CT (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES LAB,AMES,IA 50011, USA. RI Soukoulis, Costas/A-5295-2008 NR 18 TC 112 Z9 115 U1 0 U2 6 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 OCT 7 PY 1991 VL 16 IS 6 BP 563 EP 568 DI 10.1209/0295-5075/16/6/009 PG 6 WC Physics, Multidisciplinary SC Physics GA GK203 UT WOS:A1991GK20300009 ER PT J AU EILAM, G HEWETT, JL SONI, A AF EILAM, G HEWETT, JL SONI, A TI CP ASYMMETRIES INDUCED BY PARTICLE WIDTHS - APPLICATION TO TOP-QUARK DECAYS SO PHYSICAL REVIEW LETTERS LA English DT Article ID B->KL+L AB An on-shell unstable particle produced in a tree-level process, such as W in t --> qW, induces a CP violating signal through its width. This effect arises from an Im(tree) x Re(loop) type of interference. Among t --> qq'qBAR processes (e.g., t --> bcbBAR) proceeding either through the tree-level t --> qW or the one-loop t --> q' + (vitual g) reactions, the CP asymmetry is largest for the case t --> dcdBAR and is of O(eta/lambda-2) in Wolfenstein's parametrization. The resulting effects are found to be small in the standard model, but are much larger than those obtained for radiative top-quark decays. We also briefly discuss B decays where such a mechanism may cause CP violation in, for example, b --> se + e-. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. TECHNION ISRAEL INST TECHNOL,DEPT PHYS,IL-32000 HAIFA,ISRAEL. RP EILAM, G (reprint author), MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824, USA. NR 20 TC 53 Z9 53 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 OCT 7 PY 1991 VL 67 IS 15 BP 1979 EP 1981 DI 10.1103/PhysRevLett.67.1979 PG 3 WC Physics, Multidisciplinary SC Physics GA GJ319 UT WOS:A1991GJ31900011 ER PT J AU LLOR, A OLEJNICZAK, Z SACHLEBEN, J PINES, A AF LLOR, A OLEJNICZAK, Z SACHLEBEN, J PINES, A TI SCALING AND TIME-REVERSAL OF SPIN COUPLINGS IN ZERO-FIELD NMR SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; MULTIPLE-PULSE NMR; LIQUIDS; NQR AB We report the observation of spin echoes resulting from the time reversal of isotropic many-body spin couplings in zero-field NMR. The coherent-averaging pulse sequences responsible for the scaling and the time reversal of isotropic interactions of first and second rank are based on cubic and icosahedral symmetry. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. RP LLOR, A (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 25 TC 14 Z9 14 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 OCT 7 PY 1991 VL 67 IS 15 BP 1989 EP 1992 DI 10.1103/PhysRevLett.67.1989 PG 4 WC Physics, Multidisciplinary SC Physics GA GJ319 UT WOS:A1991GJ31900014 ER PT J AU GONZALEZ, R HODGSON, ER BALLESTEROS, C CHEN, Y AF GONZALEZ, R HODGSON, ER BALLESTEROS, C CHEN, Y TI EFFECT OF ENVIRONMENT ON RADIATION-INDUCED OUTDIFFUSION OF DEUTERONS AND PROTONS FROM CRYSTALLINE LINBO3 AT LOW-TEMPERATURES SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIFFUSED LINBO3; SINGLE-CRYSTALS; HYDROGEN AB Hydrogenic species (protons and deuterons) are removed efficiently from single crystals of LiNbO3 during electron irradiation in vacuum near room temperature. Irradiation in air produces no significant change in the concentration of the hydrogenic species. C1 CTR INVEST ENERGET MEDIOAMBIENTALES & TECHNOL,DIV FUS,E-28040 MADRID,SPAIN. UNIV COMPLUTENSE MADRID,FAC CIENCIAS FIS,DEPT FIS MAT,E-28040 MADRID,SPAIN. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP GONZALEZ, R (reprint author), UNIV POLITECN MADRID,ESCUELA TECN SUPER ARQUITECTURA,DEPT FIS APLICADA,E-28040 MADRID,SPAIN. OI BALLESTEROS, CARMEN INES/0000-0002-8983-4751 NR 21 TC 14 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD OCT 7 PY 1991 VL 67 IS 15 BP 2057 EP 2059 DI 10.1103/PhysRevLett.67.2057 PG 3 WC Physics, Multidisciplinary SC Physics GA GJ319 UT WOS:A1991GJ31900031 ER PT J AU SIGMAN, ME ZINGG, SP PAGNI, RM BURNS, JH AF SIGMAN, ME ZINGG, SP PAGNI, RM BURNS, JH TI PHOTOCHEMISTRY OF ANTHRACENE IN WATER SO TETRAHEDRON LETTERS LA English DT Article DE ANTHRACENE; PHOTOCHEMISTRY; PHOTOOXIDATION; WATER ID QUANTUM YIELDS; HYDROXYLATION; PHOTOLYSIS AB Photolysis of anthracene (350 nm) in aerated water yields endoperoxide and 9,10-anthraquinone as the major primary photoproducts. Photolysis of anthracene in oxygen-deficient aqueous solutions yields the three isomers of 10,10'-dihydroxy-9,9',10,10'-tetrahydro-9,9'-bianthryl as the primary photoproduct. Involvement of a cation radical mechanism is suggested. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. RP SIGMAN, ME (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 16 TC 37 Z9 37 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD OCT 7 PY 1991 VL 32 IS 41 BP 5737 EP 5740 DI 10.1016/S0040-4039(00)93543-3 PG 4 WC Chemistry, Organic SC Chemistry GA GL666 UT WOS:A1991GL66600025 ER PT J AU GUO, J ELLIS, DE LAM, DJ AF GUO, J ELLIS, DE LAM, DJ TI ELECTRONIC-STRUCTURE OF PURE AND K-DOPED C60 CLUSTERS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ICOSAHEDRAL C-60; BUCKMINSTERFULLERENE; CARBON; MOLECULES; EFFICIENT AB The electronic structure of a C60 cluster, the soccer ball-shaped structure determined from the recent X-ray study by Hawkins et al., and of its endohedral complex KC60 were calculated using the self-consistent-field discrete variational (DV) method in the local density theoretical framework. The calculated C60 cluster energy levels were found in excellent agreement with the recent X-ray photoemission spectra (XPS) of Weaver et al. The ionization potential and electron affinity calculated using the transition state method are in good agreement with the experimental data. It was found that electronic structure of the endohedral complex KC60 cluster is the same as the C60 except that K donates one electron into the lowest unoccupied molecular orbital of C60. The electronic charge density of C60 was found to lie within a spherical shell of almost-equal-to 8.0 au thickness surrounding the C nuclei. A cage of almost-equal-to 2.0 au radius at the center of the C60 cluster was found nearly free of electrons (rho << 10(-3) e/a0(3)). The 29 eV plasma energy loss calculated approximately from the dielectric function of C60 explains the broad satellite feature seen almost-equal-to 28 eV to the higher energy side from the C 1s core line in the XPS experiment. RP GUO, J (reprint author), ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 29 TC 30 Z9 30 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD OCT 4 PY 1991 VL 184 IS 5-6 BP 418 EP 422 DI 10.1016/0009-2614(91)80011-L PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GK130 UT WOS:A1991GK13000011 ER PT J AU KNICKELBEIN, MB MENEZES, WJC AF KNICKELBEIN, MB MENEZES, WJC TI METAL CLUSTER-RARE GAS VANDERWAALS COMPLEXES - NBNARM AND FENKRM SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ABSORPTION-FINE-STRUCTURE; IONIZATION-POTENTIALS; PHOTOIONIZATION; PHOTODISSOCIATION; SPECTROSCOPY; ENERGY; ALAR AB Van der Waals complexes of niobium clusters with argon atoms and iron clusters with krypton atoms have been produced in a supersonic expansion using a laser vaporization cluster source cooled to 77 K. Laser photoionization time-of-flight mass spectra reveal significant nonmonotonic cluster size dependence in the extent of formation for both NbnArm and FenKr species. Photoionization efficiency (PIE) spectra have been recorded for selected NbnArm species for n less-than-or-equal-to 20. For a given n, ionization potentials (IPs) assigned from PIE threshold behavior decrease with increasing m, as predicted by a simple charge-induced dipole electrostatic model. RP KNICKELBEIN, MB (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 19 TC 30 Z9 30 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD OCT 4 PY 1991 VL 184 IS 5-6 BP 433 EP 438 DI 10.1016/0009-2614(91)80014-O PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GK130 UT WOS:A1991GK13000014 ER PT J AU HECKER, SS AF HECKER, SS TI BRAIN-TUMOR INCIDENCE AT LOS-ALAMOS SO SCIENCE LA English DT Letter RP HECKER, SS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD OCT 4 PY 1991 VL 254 IS 5028 BP 11 EP 11 DI 10.1126/science.1925550 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GH605 UT WOS:A1991GH60500002 PM 1925548 ER PT J AU HUGHES, RC RICCO, AJ BUTLER, MA MARTIN, SJ AF HUGHES, RC RICCO, AJ BUTLER, MA MARTIN, SJ TI CHEMICAL MICROSENSORS SO SCIENCE LA English DT Article ID ACOUSTIC-WAVE SENSOR; ORGANIC VAPORS; GAS SENSORS; DEVICES; FILMS; CONDUCTIVITY; ADSORPTION; PALLADIUM; DETECTOR; SILVER AB Recent developments in the field of chemical microsensors are leading to new applications for which these devices have the potential to supplement or replace traditional analytical chemical instrumentation. The fundamentals of current microelectronic, acoustic wave, optical fiber, and electrochemical microsensors are presented, and a few recent, exciting results in these areas are described. Although future opportunities in the microsensor field are numerous, many significant problems, the majority of them related to the materials utilized for the chemically sensitive layers that are the "front end" of these devices, remain to be explored and solved. RP SANDIA NATL LABS, DIV MICROSENSOR, ALBUQUERQUE, NM 87185 USA. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 65 TC 101 Z9 101 U1 4 U2 26 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD OCT 4 PY 1991 VL 254 IS 5028 BP 74 EP 80 DI 10.1126/science.254.5028.74 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GH605 UT WOS:A1991GH60500030 PM 17739955 ER PT J AU NESBITT, FL MARSTON, G STIEF, LJ WICKRAMAARATCHI, MA TAO, W KLEMM, RB AF NESBITT, FL MARSTON, G STIEF, LJ WICKRAMAARATCHI, MA TAO, W KLEMM, RB TI MEASUREMENT OF THE PHOTOIONIZATION SPECTRA AND IONIZATION THRESHOLDS OF THE H2CN AND D2CN RADICALS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID INTER-STELLAR CLOUDS; ELECTRONIC-SPECTRA; HCN; CHEMISTRY; HYDROGEN; CONSTANT; BEARING; ISOMERS; RATIOS; ION AB The photoionization spectra of the H2CN and D2CN radicals were obtained by photoionization mass spectrometry (PIMS) using synchrotron radiation. The radicals were generated by the reaction of N with CH3 and CD3, respectively. For both H2CN and D2CN a prominent feature was observed near 118.6 nm (10.5 eV) and the ionization threshold was determined to be 9.4 +/- 0.1 eV; both features provide additional signatures for identifying H2CN in complex systems. By use of a corrected value for DELTA-H(f) (H2CN) derived from a recent electron affinity measurement and other available measured or calculated thermochemical quantities for H2CN and HCNH radicals and radical ions, a value of 10.8 +/- 0.6 eV for the ionization energy of H2CN was derived. The much lower value derived for the ionization energy of HCNH (6.8 and 7.0 eV for the cis and trans isomers, respectively) is consistent with the product of the N + CH3 reaction being the H2CN isomer and not HCNH. The ionization threshold observed at 9.4 eV is attributed to autoionization arising from high Rydberg states of H2CN which couple into vibrationally excited states of the linear HCNH+ ground state of the ion. Also discussed are the roles of the H2CN radical and HCNH+ radical ion in the chemistry of the atmosphere of Titan and in interstellar clouds. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,ASTROCHEM BRANCH,GREENBELT,MD 20771. BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RI Marston, George/J-9223-2012; Marston, George/B-3116-2015 OI Marston, George/0000-0002-0050-5928; Marston, George/0000-0002-0050-5928 NR 47 TC 34 Z9 34 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 3 PY 1991 VL 95 IS 20 BP 7613 EP 7617 DI 10.1021/j100173a012 PG 5 WC Chemistry, Physical SC Chemistry GA GH893 UT WOS:A1991GH89300012 ER PT J AU MORTLOCK, RF BELL, AT RADKE, CJ AF MORTLOCK, RF BELL, AT RADKE, CJ TI INCORPORATION OF ALUMINUM INTO SILICATE ANIONS IN AQUEOUS AND METHANOLIC SOLUTIONS OF TMA SILICATES SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; SI-29 NMR-SPECTROSCOPY; POTASSIUM SILICATE; ALUMINOSILICATE SOLUTIONS; EXCHANGE; RELAXATION; PRECURSORS; PATTERNS AB Si-29 and Al-27 NMR spectroscopies were used to characterize dilute, highly alkaline, aqueous and methanolic solutions of tetramethylammonium (TMA) aluminosilicates. The solutions contained 2 mol % SiO2, a silicate ratio (R = [SiO2]/[M2O], M+ = TMA+) of 2, Si/Al molar ratios between infinity and 2, and between 0 and 20 mol % methanol (MeOH). TMA aluminosilicate solutions are characterized by a high concentration of double four membered ring (D4R) anions. Si-29 NMR peaks were observed for Si atoms in the dimer, linear trimer, cyclic trimer, branched cyclic trimer, and D4R anions which have one incorporated Al atom. Si-29 NMR peak assignments were based on similar assignments in tetrapropylammonium (TPA) aluminosilicate solutions and confirmed by using the correlation between the partial charge of Si atoms and the Si-29 NMR chemical shift. Comparison between the distribution of silicate and aluminosilicate oligomers in TMA and TPA aluminosilicate solutions indicates that the distribution of Si atoms among anions is very different, but the level of Al incorporation into silicate species is remarkably similar. As a result, the incorporation of Al into silicate anions depends strongly on the solution composition and pH and depends only weakly on the nature of the alkylammonium base. Due to a hydrophobic effect, the addition of methanol to TMA aluminosilicate solutions increases the concentration of D4R and D4R(1A1) anions. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, CTR ADV MAT, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, DEPT CHEM ENGN, BERKELEY, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 37 TC 37 Z9 39 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD OCT 3 PY 1991 VL 95 IS 20 BP 7847 EP 7851 DI 10.1021/j100173a054 PG 5 WC Chemistry, Physical SC Chemistry GA GH893 UT WOS:A1991GH89300054 ER PT J AU HUNT, RD ANDREWS, L TOTH, LM AF HUNT, RD ANDREWS, L TOTH, LM TI MATRIX INFRARED-SPECTRA OF HCL COMPLEXES WITH UF6, WF6, AND MOF6 SO INORGANIC CHEMISTRY LA English DT Article ID SOLID ARGON; HYDROGEN; CONSTANTS; DIMERS; NEON; CIF; N-2 AB HCl complexes with UF6, WF6, and MoF6 were prepared in solid argon at 12 K. The FTIR spectrum of UF6/HCl contained a doublet at 2850.6 and 2849.7 cm-1 due to the hydrogen-bonded UF6-HCl complex. In contrast, the HCl interaction with WF6, as well as MoF6 produced two distinctly different 1:1 complexes. The 2862.1-cm-1 absorption due to the antihydrogen-bonded complex, WF6-ClH, was slightly more intense than the 2866.2-cm-1 absorption of the hydrogen-bonded complex, WF6-HCl. The frequencies and relative intensities of the absorptions for the MoF6 complexes with HCl were very similar to those of their WF6 counterparts. C1 UNIV VIRGINIA,DEPT CHEM,CHARLOTTESVILLE,VA 22901. RP HUNT, RD (reprint author), OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831, USA. NR 12 TC 5 Z9 5 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD OCT 2 PY 1991 VL 30 IS 20 BP 3829 EP 3832 DI 10.1021/ic00020a011 PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA GH746 UT WOS:A1991GH74600011 ER PT J AU QI, G JEFFREY, GA RUBLE, JR MCMULLAN, RK AF QI, G JEFFREY, GA RUBLE, JR MCMULLAN, RK TI A SINGLE-CRYSTAL NEUTRON-DIFFRACTION REFINEMENT OF BENZAMIDE AT 15-K AND 123-K SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID GEOMETRY AB C7H7NO, P2(1)/c with Z = 4, cell dimensions at 15 K [123K] are a = 5.529(1) [5.549(1)], b = 5.033(1) [5.033(1)], c = 21.343(3) [21.548(4) angstrom, beta = 88.73(1) [89.22(1)]-degrees, V = 593.77(1) [601.74(1)] angstrom 3, D(m) = 1.358 [1.337] g cm-3. 2364 [2377] symmetry-independent reflections were measured at the Brookhaven High Flux Reactor [lambda = 1.0411(1) angstrom]. Structure refinement gave values of R(F2) = 0.044 [0.063]. A rigid-body thermal motion analysis was applied. The internal modes for the C-H and N-H bonds were calculated. The benzene ring has a small B5(2) distortion, with Benzene C-C bond lengths, corrected for thermal motion, ranging from 1.392(1) to 1.401(1) angstrom. The internal ring angles are 119.7(1) to 120.1(1)-degrees. The amide bond lengths are C-C 1.498(1), C = O 1.246(1) and C-N 1.341(1) angstrom. Benzene C-H bond lengths range from 1.084(2) to 1.089(2) angstrom and N-H bond lengths are 1.013(2) and 1.022(2) angstrom. The plane of the amide group makes an angle of 25.2(1)-degrees with the mean plane of the benzene ring. C1 UNIV PITTSBURGH,DEPT CRISTALLOG,PITTSBURGH,PA 15260. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. NR 13 TC 1 Z9 1 U1 2 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Commun. PD OCT 1 PY 1991 VL 47 BP 742 EP 745 PN 5 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GL012 UT WOS:A1991GL01200021 ER PT J AU GOURDIN, WH LASSILA, DH AF GOURDIN, WH LASSILA, DH TI FLOW-STRESS OF OFE COPPER AT STRAIN RATES FROM 10-3 TO 104S-1 - GRAIN-SIZE EFFECTS AND COMPARISON TO THE MECHANICAL THRESHOLD STRESS MODEL SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID EXPANDING RING; CREEP AB The results of electromagnetically launched expanding-ring experiments and conventional compression tests with 10- to 200-mu-m-grain-sized oxygen-free electronic (OFE) copper are reported and analyzed in terms of the mechanical threshold stress (MTS) model. The activation energy for slip and the strain-rate pre-exponential are taken from the literature, but other model parameters are derived from the present data. We find that the work hardening, d-sigma/d-epsilon, varies significantly with the strain rate but is independent of the grain size. This implies that the grain-size dependence, which is well described by a Hall-Petch relationship, must be assigned to the structure independent, or "athermal," component of the MTS description of the flow stress. The model parameters associated with dynamic recovery are critical to the description of the high-temperature, high-strain-rate ring data, and we find values slightly different from those in the literature. Overall, however, the MTS model provides an excellent description of the material behavior over a wide range of grain size, strain rate, and temperature. In particular, it successfully reproduces the interplay between temperature and strain rate that occurs during ring expansion. RP GOURDIN, WH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, POB 808, LIVERMORE, CA 94551 USA. NR 23 TC 44 Z9 44 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD OCT PY 1991 VL 39 IS 10 BP 2337 EP 2348 DI 10.1016/0956-7151(91)90015-S PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GF315 UT WOS:A1991GF31500015 ER PT J AU HURT, RH ALLENDORF, MD AF HURT, RH ALLENDORF, MD TI MODEL OF PARTICLE-VAPOR CODEPOSITION WITH APPLICATION TO CERAMIC MATERIALS SYNTHESIS SO AICHE JOURNAL LA English DT Article ID DIFFUSION-CONTROLLED DEPOSITION; BALLISTIC DEPOSITION; POWDERS; SILICON; NUCLEATION; SURFACES; FILMS AB The simultaneous deposition of particles and material from the vapor phase gives rise to surface deposits having characteristic structure. A mathematical model of the particle-vapor codeposition process is developed that predicts the structure and properties of these deposits as well as their growth rate over a wide range of conditions. A random sphere formulation is developed that provides the framework for a unified treatment of both subprocesses: ballistic particle deposition and porous media densification through vapor deposition. The model is applied to particle-enhanced chemical vapor deposition (PECVD) processes for the production of ceramic materials. In PECVD, particles are introduced into a CVD process, either in the form of an aerosol created in situ by a controlled amount of gas-to-particle conversion or in the form of independently charged powder. The model identifies PECVD conditions that produce deposition rates substantially higher than those achievable by conventional CVD. RP HURT, RH (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 34 TC 9 Z9 9 U1 1 U2 3 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD OCT PY 1991 VL 37 IS 10 BP 1485 EP 1496 DI 10.1002/aic.690371006 PG 12 WC Engineering, Chemical SC Engineering GA GK652 UT WOS:A1991GK65200005 ER PT J AU OMATETE, OO JANNEY, MA STREHLOW, RA AF OMATETE, OO JANNEY, MA STREHLOW, RA TI GELCASTING - A NEW CERAMIC FORMING PROCESS SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article RP OMATETE, OO (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 16 TC 380 Z9 454 U1 9 U2 58 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7812 J9 AM CERAM SOC BULL JI Am. Ceram. Soc. Bull. PD OCT PY 1991 VL 70 IS 10 BP 1641 EP & PG 0 WC Materials Science, Ceramics SC Materials Science GA GJ492 UT WOS:A1991GJ49200010 ER PT J AU MATLOCK, D BUCHAN, RM TILLERY, M AF MATLOCK, D BUCHAN, RM TILLERY, M TI A LOCAL EXHAUST VENTILATION SYSTEM TO REDUCE AIRBORNE RIBAVIRIN CONCENTRATIONS SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article AB A local exhaust hood was designed and built to capture and contain aerosol emissions of ribavirin during drug administration. The newly designed over-the-head hood is similar to the single hood currently used to administer the drug. This new hood was surrounded by an exhaust plenum to form a compound hood configuration. The exhaust plenum was connected to a filtered local exhaust air system to remove the waste aerosol. The compound hood and local exhaust ventilation system were evaluated for leak rate and inside hood aerosol concentration as a function of exhaust flow rates. This hood reduced the leak rate from an average of 98% with the traditional head hood to an average of less than 1% with the compound hood with exhaust port. The compound hood did not perform quite as well when not in use (set aside during infant caretaking) with the nebulizer remaining on. The leak rate was found to increase from an average of less than 1% to an average of 12% when trials were conducted that used a doll as a simulated patient versus trials without a doll, respectively. As regards therapeutic dose inside the hood, the system's performance may lead to an 18% to 25% decrease in inside hood concentration of aerosol entering the hood. Optimum hood operating parameters were identified. An exhaust flow rate in the range from 1.0 Lpm below to 1.0 Lpm above inlet flow rate from the small particle aerosol generator (SPAG nebulizer) reduced the leak rate to an average of less than 1%. The compound hood was found to reduce the aerosol concentration in the room by 126x as compared to the single hood system currently being used. C1 UNIV CALIF LOS ALAMOS SCI LAB,IND HYG GRP HSE-5,LOS ALAMOS,NM 87545. COLORADO STATE UNIV,DEPT ENVIRONM HLTH,OCCUPAT HLTH SECT,FT COLLINS,CO 80523. RP MATLOCK, D (reprint author), EXXON CHEM AMERICAS,DEPT MED & ENVIRONM HLTH,13501 KATY FREEWAY,HOUSTON,TX 77079, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD OCT PY 1991 VL 52 IS 10 BP 428 EP 432 PG 5 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA HP689 UT WOS:A1991HP68900008 PM 1951053 ER PT J AU LIU, Z LEE, TS KOTEK, TJ AF LIU, Z LEE, TS KOTEK, TJ TI A 2ND FOLLOW-UP OF MORTALITY AMONG MALE WORKERS AT A THORIUM-PROCESSING PLANT SO AMERICAN JOURNAL OF EPIDEMIOLOGY LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER J EPIDEMIOLOGY PI BALTIMORE PA 624 N BROADWAY RM 225, BALTIMORE, MD 21205 SN 0002-9262 J9 AM J EPIDEMIOL JI Am. J. Epidemiol. PD OCT 1 PY 1991 VL 134 IS 7 BP 744 EP 744 PG 1 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA GN535 UT WOS:A1991GN53500120 ER PT J AU DEJONG, PJ AMEMIYA, C ASLANIDIS, C ALEGRIA, M ALLEMAN, J CHEN, C COPELAND, A ELLIOTT, J GARCIA, E OLSEN, A CARRANO, AV AF DEJONG, PJ AMEMIYA, C ASLANIDIS, C ALEGRIA, M ALLEMAN, J CHEN, C COPELAND, A ELLIOTT, J GARCIA, E OLSEN, A CARRANO, AV TI CLOSURE OF THE CHROMOSOME 19 COSMID-CONTIG MAP USING CLONE POOLING SCHEMES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 10 EP 10 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900052 ER PT J AU CARRANO, AV AMEMIYA, C ASLANIDIS, C BRANDRIFF, B BRANSCOMB, EW DEJONG, PJ GARCIA, E MOHRENWEISER, H OLSEN, A TRASK, B TYNAN, K AF CARRANO, AV AMEMIYA, C ASLANIDIS, C BRANDRIFF, B BRANSCOMB, EW DEJONG, PJ GARCIA, E MOHRENWEISER, H OLSEN, A TRASK, B TYNAN, K TI CONSTRUCTING A PHYSICAL MAN OF HUMAN CHROMOSOME-19 - STRATEGIES AND RESULTS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 35 EP 35 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900176 ER PT J AU TRASK, B FERTITTA, A CHRISTENSEN, M MASSA, HF BRANDRIFF, B BRANSCOMB, E DEJONG, P GORDON, L MOHRENWEISER, H OLSEN, A TYNAN, K VANDENENGH, G CARRANO, AV AF TRASK, B FERTITTA, A CHRISTENSEN, M MASSA, HF BRANDRIFF, B BRANSCOMB, E DEJONG, P GORDON, L MOHRENWEISER, H OLSEN, A TYNAN, K VANDENENGH, G CARRANO, AV TI PHYSICAL MAPPING OF CHROMOSOME-19 BY FLUORESCENCE INSITU HYBRIDIZATION TO INTERPHASE AND METAPHASE NUCLEI SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 37 EP 37 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900182 ER PT J AU CLIFT, SM KRAUSS, RM SPANGLER, EA VERSTUYFT, JG RUBIN, EM AF CLIFT, SM KRAUSS, RM SPANGLER, EA VERSTUYFT, JG RUBIN, EM TI HUMAN APOLIPOPROTEIN A-1 PREVENTS POLYGENIC ATHEROSCLEROSIS IN TRANSGENIC MICE SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV RES MED,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 39 EP 39 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900194 ER PT J AU TUCKER, ID ALLEN, NA ELLIOTT, J GARCIA, E AF TUCKER, ID ALLEN, NA ELLIOTT, J GARCIA, E TI DEVELOPMENT OF SYNTHETIC, MOLECULARLY-DEFINED CHROMOSOME-BANDING PATTERNS USING FLUORESCENCE INSITU HYBRIDIZATION OF YEAST ARTIFICIAL CHROMOSOMES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94551. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 40 EP 40 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900198 ER PT J AU KALLIONIEMI, OP KALLIONIEMI, A WALDMAN, F NGO, J CHEN, LC SMITH, H PINKEL, D GRAY, JW AF KALLIONIEMI, OP KALLIONIEMI, A WALDMAN, F NGO, J CHEN, LC SMITH, H PINKEL, D GRAY, JW TI INTERPHASE CYTOGENETICS IN HUMAN BREAST-CANCER USING LOCUS-SPECIFIC PROBES - DETECTION OF ONCOGENE AMPLIFICATION AND LOSS OF TUMOR-SUPPRESSOR GENE BY FLUORESCENCE INSITU HYBRIDIZATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,GBCRI,SAN FRANCISCO,CA 94143. RI Kallioniemi, Olli/H-4738-2012; Kallioniemi, Olli/H-5111-2011 OI Kallioniemi, Olli/0000-0002-3231-0332; Kallioniemi, Olli/0000-0002-3231-0332 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 44 EP 44 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900219 ER PT J AU JANSEN, G DEJONG, P VOOYS, M ASLANIDIS, C KORNELUK, B SHUTLER, G WORMSKAMP, N SMEETS, B ROPERS, HH WIERINGA, B AF JANSEN, G DEJONG, P VOOYS, M ASLANIDIS, C KORNELUK, B SHUTLER, G WORMSKAMP, N SMEETS, B ROPERS, HH WIERINGA, B TI GENETIC AND PHYSICAL DEFINITION OF THE MYOTONIC-DYSTROPHY GENE REGION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 CATHOLIC UNIV NIJMEGEN,DEPT CELL BIOL,NIJMEGEN,NETHERLANDS. CATHOLIC UNIV NIJMEGEN,DEPT HISTOL,NIJMEGEN,NETHERLANDS. CATHOLIC UNIV NIJMEGEN,DEPT HUMAN GENET,NIJMEGEN,NETHERLANDS. LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. CHILDRENS HOSP EASTERN ONTARIO,DIV GENET,OTTAWA K1H 8L1,ONTARIO,CANADA. RI Wieringa, Berend/A-5346-2011 OI Wieringa, Berend/0000-0001-9192-8020 NR 0 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 82 EP 82 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30900402 ER PT J AU WYROBEK, AJ STILWELL, JL SEGRAVES, M BARTON, D PINKEL, D AF WYROBEK, AJ STILWELL, JL SEGRAVES, M BARTON, D PINKEL, D TI DETECTION OF CHROMOSOME-SPECIFIC REPETITIVE SEQUENCES IN HUMAN SPERM USING FLUORESCENCE INSITU HYBRIDIZATION WITH DNA PROBES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 235 EP 235 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901279 ER PT J AU YU, LC FLANDERMEYER, B SEGRAVES, R SAKAMOTO, M KALLIONIEMI, A VOOIJS, M WEIER, HU KALLIONIEMI, O GOLBUS, M GRAY, I AF YU, LC FLANDERMEYER, B SEGRAVES, R SAKAMOTO, M KALLIONIEMI, A VOOIJS, M WEIER, HU KALLIONIEMI, O GOLBUS, M GRAY, I TI EVALUATION OF CHROMOSOME-SPECIFIC PROBES FOR PRENATAL-DIAGNOSIS OF NUMERICAL CHROMOSOME-ABERRATIONS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RI Kallioniemi, Olli/H-4738-2012; Kallioniemi, Olli/H-5111-2011 OI Kallioniemi, Olli/0000-0002-3231-0332; Kallioniemi, Olli/0000-0002-3231-0332 NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 235 EP 235 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901280 ER PT J AU YU, CW CURRY, CJR STAMMER, V KUO, WL AF YU, CW CURRY, CJR STAMMER, V KUO, WL TI IDENTIFICATION OF A DENOVO COMPLEX 4-WAY TRANSLOCATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,VALLEY CHILDRENS HOSP,FRESNO,CA. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 279 EP 279 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901545 ER PT J AU WEIER, HU ZITZELSBERGER, HF ROSETTE, CD MATSUTA, M MATSUTA, M GRAY, JW AF WEIER, HU ZITZELSBERGER, HF ROSETTE, CD MATSUTA, M MATSUTA, M GRAY, JW TI GENERATION OF HIGHLY SPECIFIC DNA PROBES FOR CYTOGENETIC ANALYSES OF INTERPHASE CELLS - ISOLATION AND ENZYMATIC-SYNTHESIS OF ALPHA SATELLITE DNA PROBES FOR HUMAN CHROMOSOME-8, CHROMOSOME-10, AND CHROMOSOME-12 SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. GESELL SCHWERIONENFORSCH MBH,FORSCHUNGSZENTRUM UMWELT & GESUNDHEIT,INST STRAHLENBIOL,NEUHERBERG,GERMANY. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 294 EP 294 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901631 ER PT J AU MEYNE, J MOYZIS, RK AF MEYNE, J MOYZIS, RK TI CHROMOSOMAL LOCALIZATION OF SIMPLE SEQUENCE COMPONENTS OF HUMAN SATELLITE DNA FAMILIES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 304 EP 304 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901694 ER PT J AU WILLIAMS, J YU, LC VOOIJS, M WEIER, HU SAKAMOTO, M SEGRAVES, R WANG, BT GRAY, J YING, KL AF WILLIAMS, J YU, LC VOOIJS, M WEIER, HU SAKAMOTO, M SEGRAVES, R WANG, BT GRAY, J YING, KL TI IDENTIFICATION OF MARKER CHROMOSOME IN PRENATAL-DIAGNOSIS BY FLUORESCENCE INSITU HYBRIDIZATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 PRENATAL DIAGNOST CTR SO CALIF,BEVERLY HILLS,CA. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CHILDRENS HOSP,DIV MED GENET,LOS ANGELES,CA 90027. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 309 EP 309 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901723 ER PT J AU NICHOLLS, RD NEUMANN, PE HORSTHEMKE, B RINCHIK, G AF NICHOLLS, RD NEUMANN, PE HORSTHEMKE, B RINCHIK, G TI MAPPING OF LOCI DELETED IN ANGELMAN AND PRADER-WILLI SYNDROMES IDENTIFIES CONSERVATION OF SYNTENY IN MICE AND POSSIBLE ANIMAL-MODELS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,SCH MED,BOSTON,MA 02115. UNIV ESSEN GESAMTHSCH,W-4300 ESSEN 1,GERMANY. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 3 TC 1 Z9 1 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 334 EP 334 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901867 ER PT J AU CHEN, DJ PARK, MS SICILIANO, MJ OSHIMURA, M AF CHEN, DJ PARK, MS SICILIANO, MJ OSHIMURA, M TI MAPPING OF A HUMAN RADIATION REPAIR GENE, XRCC5, BY SOMATIC-CELL HYBRIDIZATION, MICROCELL-MEDIATED CHROMOSOME TRANSFER AND X-RAY HYBRID ANALYSIS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 TOTTORI UNIV,SCH LIFE SCI,TOTTORI 680,JAPAN. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87544. UNIV TEXAS,MD ANDERSON TUMOR INST,CTR SYST CANC,HOUSTON,TX 77025. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 338 EP 338 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30901890 ER PT J AU SAKAMOTO, M PINKEL, D MASCIO, L SUDAR, D PETERS, D DRABKIN, H NAKAMURA, Y GRAY, J AF SAKAMOTO, M PINKEL, D MASCIO, L SUDAR, D PETERS, D DRABKIN, H NAKAMURA, Y GRAY, J TI SEMIAUTOMATED PROBE MAPPING BY FLUORESCENCE INSITU HYBRIDIZATION (FISH) WITH DIGITAL IMAGING MICROSCOPY SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV COLORADO,DENVER,CO 80202. JAPANESE FDN CANC RES,INST CANC,TOKYO 170,JAPAN. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 371 EP 371 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902084 ER PT J AU DOGGETT, NA STALLINGS, RL SUTHERLAND, GR CALLEN, DF OKUMURA, K WARD, DC DIETZBAND, J HILDEBRAND, CE MOYZIS, RK AF DOGGETT, NA STALLINGS, RL SUTHERLAND, GR CALLEN, DF OKUMURA, K WARD, DC DIETZBAND, J HILDEBRAND, CE MOYZIS, RK TI INTEGRATION OF THE COSMID CONTIG MAP WITH THE CYTOGENETIC AND GENETIC-LINKAGE MAPS OF HUMAN CHROMSOME-16 SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87544. LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87544. ADELAIDE CHILDRENS HOSP INC,DEPT CYTOGENET & MOLEC GENET,ADELAIDE,SA 5006,AUSTRALIA. YALE UNIV,SCH MED,DEPT HUMAN GENET,NEW HAVEN,CT 06510. RI Sutherland, Grant/D-2606-2012; Callen, David/G-1975-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 377 EP 377 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902122 ER PT J AU KALLIONIEMI, A KALLIONIEMI, OP DEAVEN, L MASCIO, L SUDAR, D PETERS, D PINKEL, D GRAY, JW AF KALLIONIEMI, A KALLIONIEMI, OP DEAVEN, L MASCIO, L SUDAR, D PETERS, D PINKEL, D GRAY, JW TI PRELIMINARY CHARACTERIZATION OF CLONES FROM A CHROMOSOME-17 COSMID LIBRARY USING FLUORESCENCE INSITU HYBRIDIZATION AND DIGITAL IMAGE-ANALYSIS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. RI Kallioniemi, Olli/H-4738-2012; Kallioniemi, Olli/H-5111-2011 OI Kallioniemi, Olli/0000-0002-3231-0332; Kallioniemi, Olli/0000-0002-3231-0332 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 381 EP 381 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902145 ER PT J AU KUO, W GINGRICH, J GOEDERT, M POTIER, MC KORSMEYER, S SILVERMAN, G PINKEL, D GRAY, J AF KUO, W GINGRICH, J GOEDERT, M POTIER, MC KORSMEYER, S SILVERMAN, G PINKEL, D GRAY, J TI PHYSICAL MAPPING OF YEAST ARTIFICIAL CHROMOSOMES (YACS) ON HUMAN CHROMOSOME-21 AND CHROMOSOME-18 BY FLUORESCENCE INSITU HYBRIDIZATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MRC,CAMBRIDGE,ENGLAND. WASHINGTON UNIV,HOWARD HUGHES MED INST,ST LOUIS,MO 63130. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 382 EP 382 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902153 ER PT J AU MCCORMICK, MK MEINCKE, LJ CAMPBELL, ML CAMPBELL, EW FAWCETT, JJ DEAVEN, LL MOYZIS, RK AF MCCORMICK, MK MEINCKE, LJ CAMPBELL, ML CAMPBELL, EW FAWCETT, JJ DEAVEN, LL MOYZIS, RK TI CHROMOSOME-21 SPECIFIC YEAST ARTIFICIAL CHROMOSOME LIBRARY FROM SORTED CHROMOSOMES - CONSTRUCTION, CHARACTERIZATION AND MAPPING SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87544. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87544. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 384 EP 384 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902162 ER PT J AU TYNAN, KM BRANSCOMB, E DEJONG, P OLSEN, A TRASK, B CARRANO, AV MOHRENWEISER, HW AF TYNAN, KM BRANSCOMB, E DEJONG, P OLSEN, A TRASK, B CARRANO, AV MOHRENWEISER, HW TI ASSIGNMENT OF GENETIC-MARKERS ONTO THE COSMID CONTIG MAP OF HUMAN CHROMOSOME-19 SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 390 EP 390 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902198 ER PT J AU ELLISON, JW PASSAGE, MB YU, LC YEN, PH MOHANDAS, TK SHAPIRO, LJ AF ELLISON, JW PASSAGE, MB YU, LC YEN, PH MOHANDAS, TK SHAPIRO, LJ TI ISOLATION AND CHARACTERIZATION OF HUMAN GENES THAT ESCAPE X-INACTIVATION SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 HOWARD HUGHES MED INST,TORRANCE,CA. UNIV CALIF LOS ANGELES,HARBOR MED CTR,LOS ANGELES,CA 90024. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 404 EP 404 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902280 ER PT J AU SALIDO, EC YEN, PH KOPRIVNIKAR, K YU, L SHAPIRO, LJ AF SALIDO, EC YEN, PH KOPRIVNIKAR, K YU, L SHAPIRO, LJ TI THE HUMAN ENAMEL PROTEIN AMELOGENIN IS EXPRESSED FROM BOTH THE X AND Y CHROMOSOMES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 UNIV CALIF LOS ANGELES,LOS ANGELES CTY HARBOR MED CTR,SCH MED,HOWARD HUGHES MED INST,TORRANCE,CA 90509. FAC MED LA LAGUNA,LA LAGUNA,SPAIN. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RI Salido, Eduardo/I-2232-2015 OI Salido, Eduardo/0000-0001-9599-9854 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 418 EP 418 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902363 ER PT J AU STILWELL, JL WYROBEK, AJ AF STILWELL, JL WYROBEK, AJ TI CONSERVED DNA SEGMENTS WITHIN THE UNTRANSLATED REGIONS OF HUMAN PROTAMINE-1 AND PROTAMINE-2 CDNAS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 433 EP 433 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902455 ER PT J AU DEAVEN, LL BROWN, NC CAMPBELL, EW CAMPBELL, ML FAWCETT, JJ HILDEBRAND, CE LONGMIRE, JL MARTINEZ, A MCCORMICK, MK MEINCKE, LJ SCHOR, PL MOYZIS, RK AF DEAVEN, LL BROWN, NC CAMPBELL, EW CAMPBELL, ML FAWCETT, JJ HILDEBRAND, CE LONGMIRE, JL MARTINEZ, A MCCORMICK, MK MEINCKE, LJ SCHOR, PL MOYZIS, RK TI CONSTRUCTION OF PARTIAL DIGEST LIBRARIES FROM FLOW SORTED HUMAN-CHROMOSOMES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 440 EP 440 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902494 ER PT J AU BIGBEE, WL JENSEN, RH GRANT, SG LANGLOIS, RG OLSEN, DA AUERBACH, AD AF BIGBEE, WL JENSEN, RH GRANT, SG LANGLOIS, RG OLSEN, DA AUERBACH, AD TI EVIDENCE FOR ELEVATED INVIVO SOMATIC MUTATION AT THE GLYCOPHORIN-A LOCUS IN FANCONI ANEMIA SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. ROCKEFELLER UNIV,NEW YORK,NY 10021. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 NR 0 TC 7 Z9 7 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 446 EP 446 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902530 ER PT J AU DUPONT, BR BIGBEE, WL GRANT, SG JENSEN, RH LANGLOIS, RG AF DUPONT, BR BIGBEE, WL GRANT, SG JENSEN, RH LANGLOIS, RG TI DETECTION OF SOMATIC MUTATIONS IN CIRCULATING RETICULOCYTES - PROSPECTS FOR MOLECULAR ANALYSIS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 447 EP 447 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902536 ER PT J AU GRANT, SG LANGLOIS, RG JENSEN, RH BIGBEE, WL AF GRANT, SG LANGLOIS, RG JENSEN, RH BIGBEE, WL TI SOMATIC MUTATION AND SEGREGATION IN NORMAL INDIVIDUALS AS DETERMINED USING THE INVIVO GPA ASSAY - IMPLICATIONS FOR ONCOGENESIS AND AGING SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 448 EP 448 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902544 ER PT J AU JONES, IM BURKHARTSCHULTZ, K STROUT, CL THOMPSON, C AF JONES, IM BURKHARTSCHULTZ, K STROUT, CL THOMPSON, C TI SOMATIC MUTAGENESIS - SEQUENCE-ANALYSIS OF THE HPRT GENE IN MUTANT HUMAN-LYMPHOCYTES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NIEHS,RES TRIANGLE PK,NC 27709. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 448 EP 448 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902546 ER PT J AU SELBY, P WOYCHIK, R AF SELBY, P WOYCHIK, R TI USE OF THE MOUSE SKELETON AND LENS TO ESTIMATE GENETIC HAZARDS OF RADIATION AND CHEMICALS AND TO IDENTIFY EFFECTS OF TRANSGENES SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN 37831. METHODIST MED CTR OAK RIDGE,OAK RIDGE,TN. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 450 EP 450 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902558 ER PT J AU MOHRENWEISER, HW PERRY, BA JUDD, SA CHU, EHY AF MOHRENWEISER, HW PERRY, BA JUDD, SA CHU, EHY TI MOLECULAR APPROACHES TO SCREENING FOR DENOVO MUTATIONS IN UNSELECTED PROGENY OF MUTAGENIZED HUMAN SOMATIC-CELLS SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV MICHIGAN,ANN ARBOR,MI 48109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1991 VL 49 IS 4 SU S BP 492 EP 492 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA GR309 UT WOS:A1991GR30902805 ER PT J AU EVANS, RW AF EVANS, RW TI RECOMBINANT-HUMAN-ERYTHROPOIETIN AND THE QUALITY-OF-LIFE OF END-STAGE RENAL-DISEASE PATIENTS - A COMPARATIVE-ANALYSIS SO AMERICAN JOURNAL OF KIDNEY DISEASES LA English DT Article DE RECOMBINANT HUMAN ERYTHROPOIETIN; QUALITY OF LIFE; DIALYSIS; TRANSPLANT; EMPLOYMENT ID AMBULATORY PERITONEAL-DIALYSIS; HEMODIALYSIS-PATIENTS; CLINICAL-TRIAL; PATIENTS PTS; R-HUEPO; ANEMIA; IMPROVEMENTS; MODALITY; THERAPY; HD RP EVANS, RW (reprint author), BATTELLE SEATTLE RES CTR,HLTH & POPULAT RES CTR,4000 NE 41ST ST,SEATTLE,WA 98105, USA. NR 55 TC 52 Z9 52 U1 1 U2 3 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 SN 0272-6386 J9 AM J KIDNEY DIS JI Am. J. Kidney Dis. PD OCT PY 1991 VL 18 IS 4 SU 1 BP 62 EP 70 PG 9 WC Urology & Nephrology SC Urology & Nephrology GA GK197 UT WOS:A1991GK19700012 PM 1928082 ER PT J AU LEFF, LG BURCH, JL MCARTHUR, JV AF LEFF, LG BURCH, JL MCARTHUR, JV TI BACTERIAL USE OF DISSOLVED ORGANIC-CARBON FROM CAROLINA BAYS SO AMERICAN MIDLAND NATURALIST LA English DT Article ID MOLECULAR-WEIGHT; PRAIRIE STREAM; MATTER; GROWTH; LAKE; ASSEMBLAGES; WATERS AB Carolina bays are the most common natural lentic ecosystems on the Carolina coastal plain, yet their microbial populations have not been examined. This study examined the ability of bacteria to use dissolved organic carbon from bays of differing characteristics. The five bays studied differed in water chemistry, dissolved organic carbon (DOC) concentration and molecular size distribution of DOC, but densities of bacteria were generally similar among bays. Exposure history of the bacterial community did not preclude it from growing on DOC from different bays although there was some evidence that bacteria at a site grow best on DOC from that same site. In spite of differences in DOC concentration and composition, the ability of DOC to support bacterial growth did not differ among bays. C1 SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NR 27 TC 3 Z9 3 U1 0 U2 2 PU AMER MIDLAND NATURALIST PI NOTRE DAME PA UNIV NOTRE DAME, NOTRE DAME, IN 46556 SN 0003-0031 J9 AM MIDL NAT JI Am. Midl. Nat. PD OCT PY 1991 VL 126 IS 2 BP 308 EP 316 DI 10.2307/2426106 PG 9 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA GM891 UT WOS:A1991GM89100007 ER PT J AU HOUK, RS SHUM, SCK WIEDERIN, DR AF HOUK, RS SHUM, SCK WIEDERIN, DR TI FRONTIERS IN ELEMENTAL ANALYSIS BY MASS-SPECTROMETRY SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT SYMP ON ANALYTICAL ADVANCES FOR THE 90S, IN CELEBRATION OF THE 250TH VOLUME OF ANALYTICA CHIMICA ACTA CY MAY 23-26, 1991 CL OOTMARSUM, NETHERLANDS SP ANALYTICA CHIMICA ACTA DE MASS SPECTROMETRY; ELEMENTAL ANALYSIS; LASER DESORPTION; PLASMAS ID INDUCTIVELY COUPLED PLASMA; FLOW-INJECTION ANALYSIS; LIQUID-CHROMATOGRAPHY; ISOTOPE RATIOS; ULTRASONIC NEBULIZER; ION ASSOCIATION; GAS-PHASE; INTERFERENCES; ABSORPTION; IDENTIFICATION AB New developments in inductively coupled plasma mass spectrometry (ICP-MS) and laser desorption-time-of-flight mass spectrometry (LD-TOF-MS) for inorganic analysis are described. These include fundamental studies of the ion extraction process in ICP-MS, development of a highly efficient nebulizer, isotope tracer studies, measurement of elemental speciation by liquid chromatography with ICP-MS detection and characterization of the structures of solids by ion association. The possibilities of determining inorganic species in solutions by electrospray MS are also described. RP HOUK, RS (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,DEPT CHEM,AMES,IA 50011, USA. NR 48 TC 33 Z9 33 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD OCT 1 PY 1991 VL 250 IS 1 BP 61 EP 70 DI 10.1016/0003-2670(91)85062-W PG 10 WC Chemistry, Analytical SC Chemistry GA GL763 UT WOS:A1991GL76300006 ER PT J AU ZHU, J KATTI, AM GUIOCHON, G AF ZHU, J KATTI, AM GUIOCHON, G TI EFFECT OF DISPLACER IMPURITIES ON CHROMATOGRAPHIC PROFILES OBTAINED IN DISPLACEMENT CHROMATOGRAPHY SO ANALYTICAL CHEMISTRY LA English DT Article ID BAND PROFILES; IDEAL MODEL; SEPARATION; MIXTURE AB A major problem encountered during the development of a method in displacement chromatography has been identified and is discussed. Experimental results are presented by using the model system of phenol as the solute and 4-methyl-catechol as the displacer. Elution results showed that the displacer contained several impurities eluting prior to the major component. Analysis of the displacement profiles showed that several of these impurities pierced through the sample train eluting at the front of the solute band. This phenomenon is studied in detail, and theoretical and experimental results are presented. The results show that for the production of high-purity products, displacement chromatography must be carried out with a displacer free of early eluting impurities. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 21 TC 8 Z9 9 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 1 PY 1991 VL 63 IS 19 BP 2183 EP 2188 DI 10.1021/ac00019a020 PG 6 WC Chemistry, Analytical SC Chemistry GA GG861 UT WOS:A1991GG86100022 ER PT J AU GLASS, RS MUSKET, RG HONG, KC AF GLASS, RS MUSKET, RG HONG, KC TI PREPARATION OF SOLID MEMBRANE CHLORIDE-ION SELECTIVE ELECTRODES BY ION-IMPLANTATION SO ANALYTICAL CHEMISTRY LA English DT Note ID SILVER RP GLASS, RS (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550, USA. NR 15 TC 9 Z9 9 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD OCT 1 PY 1991 VL 63 IS 19 BP 2203 EP 2206 DI 10.1021/ac00019a025 PG 4 WC Chemistry, Analytical SC Chemistry GA GG861 UT WOS:A1991GG86100027 ER PT J AU SNYDERMAN, NJ AF SNYDERMAN, NJ TI ELECTRON RADIATIVE SELF-ENERGY OF HIGHLY STRIPPED HEAVY-ATOMS SO ANNALS OF PHYSICS LA English DT Article ID FIELD RP SNYDERMAN, NJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 31 TC 77 Z9 78 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 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD OCT PY 1991 VL 211 IS 1 BP 43 EP 86 DI 10.1016/0003-4916(91)90192-B PG 44 WC Physics, Multidisciplinary SC Physics GA GH304 UT WOS:A1991GH30400003 ER PT J AU LANGERMAN, MA MACKINNON, RJ AF LANGERMAN, MA MACKINNON, RJ TI SCALING CONSIDERATIONS FOR MODELING THE INSITU VITRIFICATION PROCESS SO APPLIED MATHEMATICAL MODELLING LA English DT Article DE INSITU; VITRIFICATION; SCALING; SIMILARITY; TEMPERATURE; POTENTIAL; OFF-GAS; JOULE HEAT; CURRENT DENSITY; MODEL, PROTOTYPE AB Thermal-electric field interactions occur in many areas of engineering. An example is the in situ vitrification process, a relatively new technology for remediating hazardous wastes. Mathematical and physical modelling of this process requires knowledge of the similarity constraints involving thermal-electric fields. This paper addresses this issue and derives the scaling relationships for modelling the remediation process from fundamental principles. Requirements for maintaining temperature and electric potential field similarity between the model and the prototype are determined as well as requirements for maintaining similarity in off-gas generation rates. A scaling rationale for designing reduced scale experiments is presented, and the results are assessed numerically. RP LANGERMAN, MA (reprint author), IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN PI WOBURN PA 225 WILDWOOD AVE #UNITB PO BOX 4500, WOBURN, MA 01801-2084 SN 0307-904X J9 APPL MATH MODEL JI Appl. Math. Model. PD OCT PY 1991 VL 15 IS 10 BP 542 EP 549 DI 10.1016/0307-904X(91)90056-U PG 8 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA GL016 UT WOS:A1991GL01600005 ER PT J AU OHKI, K ZEHR, JP FALKOWSKI, PG FUJITA, Y AF OHKI, K ZEHR, JP FALKOWSKI, PG FUJITA, Y TI REGULATION OF NITROGEN-FIXATION BY DIFFERENT NITROGEN-SOURCES IN THE MARINE NONHETEROCYSTOUS CYANOBACTERIUM TRICHODESMIUM SP NIBB1067 SO ARCHIVES OF MICROBIOLOGY LA English DT Article DE CYANOBACTERIUM; TRICHODESMIUM; NITROGEN-FIXATION; NITROGENASE ID ANABAENA-VARIABILIS; FE-PROTEIN AB The effect of various nitrogen sources on the synthesis and activity of nitrogenase was studied in the marine, non-heterocystous cyanobacterium Trichodesmium sp. NIBB1067 grown under defined culture conditions. Cells grown with N2 as the sole inorganic nitrogen source showed light-dependent nitrogenase activity (acetylene reduction). Nitrogenase activity in cells grown on N2 was not suppressed after 7 h incubation with 2 mM NaNO3 or 0.02 mM NH4Cl. However, after 3 h of exposure to 0.5 mM of urea, nitrogenase was inactivated. Cells grown in medium containing 2 mM NaNO3, 0.5 mM urea or 0.02 mM NH4Cl completely lacked the ability to reduce acetylene. Western immunoblots tested with polyclonal antisera against the Fe-protein and the Mo-Fe protein, revealed the following: (1) both the Fe-protein and the Mo-Fe protein were synthesized in cells grown with N2 as well as in cells grown with NaNO3 or low concentration of NH4Cl; (2) two bands (apparent molecular mass of 38 000 and 40 000) which cross-reacted with the antiserum to the Fe-protein, were found in nitrogen-fixing cells; (3) only one protein band, corresponding to the high molecular mass form of the Fe-protein, was found in cells grown with NaNO3 or low concentration of NH4Cl; (4) neither the Fe-protein nor the Mo-Fe protein was found in cells grown with urea; (5) the apparent molecular mass of the Fe-protein of Trichodesmium sp. NIBB1067 was about 5000 dalton higher than that of the heterocystous cyanobacterium, Anabaena cylindrica IAM-M1. C1 SUNY STONY BROOK,MARINE SCI RES CTR,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP OHKI, K (reprint author), NATL INST BASIC BIOL,DEPT CELL BIOL,OKAZAKI,AICHI 444,JAPAN. RI Zehr, Jonathan/B-3513-2014 OI Zehr, Jonathan/0000-0002-5691-5408 NR 14 TC 51 Z9 52 U1 2 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0302-8933 J9 ARCH MICROBIOL JI Arch. Microbiol. PD OCT PY 1991 VL 156 IS 5 BP 335 EP 337 DI 10.1007/BF00248706 PG 3 WC Microbiology SC Microbiology GA GL209 UT WOS:A1991GL20900001 ER PT J AU GOODSON, WH LJUNG, BM WALDMAN, F MAYALL, B CHEW, K MOORE, DH SMITH, H GOLDMAN, ES BENZ, C AF GOODSON, WH LJUNG, BM WALDMAN, F MAYALL, B CHEW, K MOORE, DH SMITH, H GOLDMAN, ES BENZ, C TI INVIVO MEASUREMENT OF BREAST-CANCER GROWTH-RATE SO ARCHIVES OF SURGERY LA English DT Article; Proceedings Paper CT 62ND ANNUAL SCIENTIFIC SESSION OF THE PACIFIC COAST SURGICAL ASSOC CY FEB 18, 1991 CL PEBBLE BEACH, CA SP PACIFIC COAST SURG ASSOC ID DNA FLOW-CYTOMETRY; PROLIFERATIVE ACTIVITY; ESTROGEN-RECEPTOR; SURVIVAL; PLOIDY AB S-phase cells of 66 primary breast cancers were labeled in vivo by preoperative infusion of the thymidine analogue bromodeoxyuridine. A monoclonal antibody specific for DNA-incorporated bromodeoxyuridine was used to identify positive cells and compute a labeling index on histologic sections. The labeling index (the percentage of cells in S-phase) ranged from 0.1% to 23.9%; it correlated positively with poorly differentiated cancer, higher mitotic counts on routine histologic examination, and tumor size; and it correlated inversely with estrogen and progesterone receptors. The labeling index did not correlate with nodal involvement or ploidy. Of the 15 patients with a labeling index greater than 12%, three died and one had systemic disease after a median follow-up of 19 months. No other patients had recurrences. There were no clinical complications of bromodeoxyuridine infusion. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. PACIFIC PRESBYTERIAN MED CTR,GERALDINE BRUSH CANC RES INST,SAN FRANCISCO,CA. UNIV CALIF SAN FRANCISCO,DEPT PATHOL,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT INTERNAL MED,SAN FRANCISCO,CA 94143. RP GOODSON, WH (reprint author), UNIV CALIF SAN FRANCISCO,MED CTR,DEPT SURG,ROOM U370,BOX 0790,SAN FRANCISCO,CA 94143, USA. FU PHS HHS [P01-44768] NR 15 TC 19 Z9 19 U1 0 U2 0 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 SN 0004-0010 J9 ARCH SURG-CHICAGO JI Arch. Surg. PD OCT PY 1991 VL 126 IS 10 BP 1220 EP 1224 PG 5 WC Surgery SC Surgery GA GJ524 UT WOS:A1991GJ52400010 PM 1929822 ER PT J AU LATTANZIO, JC VALLENARI, A BERTELLI, G CHIOSI, C AF LATTANZIO, JC VALLENARI, A BERTELLI, G CHIOSI, C TI NGC-1866 REVISITED - SEMICONVECTION VERSUS OVERSHOOT SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE STELLAR MODELS; SEMICONVECTION; CONVECTIVE OVERSHOOT; STAR CLUSTERS ID ASYMPTOTIC GIANT-BRANCH; INTERMEDIATE-MASS STARS; LARGE MAGELLANIC CLOUD; GLOBULAR-CLUSTERS; CONVECTIVE OVERSHOOT; EVOLUTIONARY MODELS; LUMINOSITY FUNCTION; STELLAR EVOLUTION; CCD PHOTOMETRY; DIAGRAMS AB We calculate a new set of stellar tracks and related isochrones that take into account the presence of semiconvection in the He-core burning phase. The stellar masses range from 2.5 to 9 M. for two values of the metallicity: Z = 0.02 and Z = 0.003. These models are compared with a set calculated with convective overshoot where the metallicity, the He content and the other parameters are homogeneous. Since the treatment of the convection in the core of a real star is affected by many uncertainties, we look at the observations of the star clusters of the Large Magellanic Cloud to discriminate among semiconvection and overshoot. In particular, we compare the theoretical models with the colour-magnitude diagram and the luminosity function of NGC 1866 previously presented by Chiosi et al. (1989). Both models reproduce the features of the colour-magnitude diagram; however only the convective overshoot hypothesis is in agreement with the observed ratio of main sequence to evolved stars. C1 UNIV PADUA, DEPT ASTRON, VICOLO OSSERV 5, I-35122 PADUA, ITALY. STERNWARTE, W-5300 BONN, GERMANY. UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. CNR, GNA, NATL COUNCIL RES, I-35100 PADUA, ITALY. NR 79 TC 19 Z9 19 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 1991 VL 250 IS 2 BP 340 EP 350 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GL424 UT WOS:A1991GL42400007 ER PT J AU YOKOYAMA, J SUTO, Y AF YOKOYAMA, J SUTO, Y TI BARYON ISOCURVATURE SCENARIO IN INFLATIONARY COSMOLOGY - A PARTICLE PHYSICS MODEL AND ITS ASTROPHYSICAL IMPLICATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY; EARLY UNIVERSE; ELEMENTARY PARTICLES; GALAXIES FORMATION ID ISOTHERMAL DENSITY PERTURBATIONS; PECULIAR VELOCITY-FIELD; QUANTUM FLUCTUATIONS; UNIVERSE SCENARIO; PHASE-TRANSITION; VIRGO CLUSTER; GALAXY; ANISOTROPY; ORIGIN; NUMBER AB A phenomenological model to produce isocurvature baryon-number fluctuations is proposed in the frame-work of inflationary cosmology. The resulting spectrum of density fluctuation is very different from the conventional Harrison-Zel'dovich shape. The model, with the parameters satisfying several requirements from particle physics and cosmology, provides an appropriate initial condition for the minimal baryon isocurvature scenario of galaxy formation discussed by Peebles. C1 NASA, FERMILAB ASTROPHYS CTR, FERMI NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. KYOTO UNIV, INST THEORET PHYS, UJI RES CTR, UJI, KYOTO 611, JAPAN. RP YOKOYAMA, J (reprint author), UNIV TOKYO, FAC SCI, DEPT PHYS, BUNKYO KU, TOKYO 113, JAPAN. NR 75 TC 34 Z9 34 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 1991 VL 379 IS 2 BP 427 EP 439 DI 10.1086/170519 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH078 UT WOS:A1991GH07800001 ER PT J AU TAVANI, M AF TAVANI, M TI HIDDEN MILLISECOND PULSARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS; GENERAL PULSARS X-RAYS; BINARIES ID X-RAY BINARIES; ECLIPSING BINARY; TERZAN-5; CATALOG AB The eclipse characteristics of the two currently known millisecond pulsars vaporizing their companion stars (PSR 1957 + 20 and PSR 1744-20A) are sufficiently different to allow a classification in three "types" of "star-vaporizing pulsars" (hereafter SVPs). PSR 1957 + 20 is the prototype of SVPs with stable eclipse properties (type I) whereas PSR 1744-24A shows a more erratic and sometimes intermittent behavior of radio-eclipses characteristics of a second class of SVPs (type II). In addition to these two SVP classes, a third class of SVPs is expected on theoretical grounds (type III). The SVPs of type III are completely engulfed by the evaporated material from the irradiated companion star, and they are therefore "hidden" pulsars because their radio-emission may be completely blocked. A quasi-steady state is possible for type III SVPs and pulsar radiation pressure and the centrifugal barrier may prevent accretion on the rapidly spinning neutron star if the companion star is underfilling its Roche lobe. The relevance of this class of binary pulsars for ROSAT and GRO observations is briefly discussed together with the possible resolution of the apparent discrepancy between the orbital period distribution of binary millisecond pulsars versus their LMXB progenitors. C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106. RP TAVANI, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550, USA. NR 28 TC 42 Z9 42 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 OCT 1 PY 1991 VL 379 IS 2 BP L69 EP L73 DI 10.1086/186156 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GH081 UT WOS:A1991GH08100007 ER PT J AU FAISON, BD AF FAISON, BD TI MICROBIAL CONVERSIONS OF LOW RANK COALS SO BIO-TECHNOLOGY LA English DT Review ID STREPTOMYCES-SETONII 75VI2; POLYPORUS-VERSICOLOR; SOLUBILIZATION; DEGRADATION; FUNGI AB Coal is the United States' most abundant nonrenewable energy resource. However, the quality of many coals is too low to offset the practical, economic, and regulatory barriers to their utilization. A variety of bacterial and fungal species have been shown to attack low rank (i.e., low-quality) coals. Technologies based on these microbial activities may be useful for the conversion of these coals to more useful products, including high-quality fuels and chemicals. Substantial developmental work will be required in order for these microbial processes to become competitive with nonbiological processes. This review summarizes the microbiological and biochemical principles underlying microbial coal conversion as a basis for predicting the practical utility of coal bio-processes. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. RP FAISON, BD (reprint author), OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831, USA. NR 58 TC 10 Z9 10 U1 2 U2 7 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 0733-222X J9 BIO-TECHNOL JI Bio-Technology PD OCT PY 1991 VL 9 IS 10 BP 951 EP 956 DI 10.1038/nbt1091-951 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA HA133 UT WOS:A1991HA13300019 ER PT J AU NICHOLS, AV BLANCHE, PJ GENZELBOROVICZENY, O FORTE, TM GONG, EL AF NICHOLS, AV BLANCHE, PJ GENZELBOROVICZENY, O FORTE, TM GONG, EL TI APOLIPOPROTEIN-SPECIFIC POPULATIONS IN HIGH-DENSITY-LIPOPROTEINS OF HUMAN CORD BLOOD SO BIOCHIMICA ET BIOPHYSICA ACTA LA English DT Article DE APOLIPOPROTEIN-SPECIFIC HDL; CHEMICAL CROSS-LINKING; FPLC; HUMAN CORD BLOOD; IMMUNOAFFINITY CHROMATOGRAPHY ID A-I; CHOLESTEROL; SERUM; PLASMA; CHROMATOGRAPHY; TRANSFORMATION AB High density lipoproteins (HDL) in human cord blood have previously been shown to exhibit particle size profiles distinctly different from those of adult HDL. The adult HDL profile is comprised of separate contributions from two major apolipoprotein-specific populations; one population contains both apolipoproteins AI and AII (HDL(AIwAII)), while the other has apolipoprotein AI without AII (HDL(AIw/oAII)). The present studies establish that cord blood HDL are also comprised of HDL(AIwAII) and HDL(AIw/oAII) populations whose particle size profiles closely reflect cholesterol and HDL-cholesterol levels in cord blood. Compared with the adult, cord blood HDL(AIwAII) profiles generally show both a greater subspeciation within HDL2a and HDL3b/3c size intervals as well as relative reduction of material in the HDL3a interval. In the cord blood HDL(AIw/oAII) profile, HDL2b(AIw/oAII) particles also show subspeciation with a major component that is consistently larger than that normally observed in the adult (11.2 vs. 10.3 nm). As in the adult, the HDL3a(AIw/oAII) component is present but, unlike the adult, its relative amount is low; hence, its peak is usually not discernable in the cord blood total HDL profile. Our studies show that the larger-sized HDL2b(AIw/oAII) of cord blood are enriched in phospholipid which probably accounts for their increased size. The protein moiety of the larger-sized HDL2b(AIw/oAII) has a molecular weight equivalent to four apolipoprotein AI molecules per particle similar to the normal-sized adult subpopulation. Phospholipid enrichment of cord blood HDL(AIwAII) subpopulations within the HDL2a size interval was not observed. However, the protein moiety of cord blood HDL2a(AIwAII) is unusual in that it exhibits an apolipoprotein AI:AII molar ratio considerably lower (0.8:1 vs. 1.6:1) than that of adult. We suggest that the unique particle size distribution of cord blood total HDL is due in large part to: (a) a specific enrichment of phospholipid in HDL2b(AIW/oAII) species, producing particles larger than normal adult counterparts and (b) an elevated proportion of apoAII carried by the HDL(AIwAII) particles that may influence subspeciation in the HDL3a/b/c size interval. RP NICHOLS, AV (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DONNER LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL 18574] NR 26 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-3002 J9 BIOCHIM BIOPHYS ACTA PD OCT 1 PY 1991 VL 1085 IS 3 BP 306 EP 314 DI 10.1016/0005-2760(91)90134-4 PG 9 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GL978 UT WOS:A1991GL97800003 PM 1911864 ER PT J AU MATTHEWS, DC APPELBAUM, FR EARY, JF HUI, TE FISHER, DR MARTIN, PJ DURACK, LD NELP, WB PRESS, OW BADGER, CC BERNSTEIN, ID AF MATTHEWS, DC APPELBAUM, FR EARY, JF HUI, TE FISHER, DR MARTIN, PJ DURACK, LD NELP, WB PRESS, OW BADGER, CC BERNSTEIN, ID TI RADIOLABELED ANTI-CD45 MONOCLONAL-ANTIBODIES TARGET LYMPHOHEMATOPOIETIC TISSUE IN THE MACAQUE SO BLOOD LA English DT Article ID ALLOGENEIC MARROW TRANSPLANTATION; ACUTE LYMPHOBLASTIC-LEUKEMIA; B-CELL LYMPHOMA; RADIOIMMUNOTHERAPY; IMMUNOGLOBULIN; TUMORS C1 UNIV WASHINGTON, DEPT PEDIAT, SEATTLE, WA 98195 USA. UNIV WASHINGTON, DEPT MED, SEATTLE, WA 98195 USA. UNIV WASHINGTON, DEPT RADIOL, SEATTLE, WA 98195 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP MATTHEWS, DC (reprint author), FRED HUTCHINSON CANC RES CTR, DIV CLIN RES, 1124 COLUMBIA ST, SEATTLE, WA 98104 USA. FU NCI NIH HHS [CA44991] NR 26 TC 44 Z9 45 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 OCT 1 PY 1991 VL 78 IS 7 BP 1864 EP 1874 PG 11 WC Hematology SC Hematology GA GH251 UT WOS:A1991GH25100029 PM 1832994 ER PT J AU BECK, SL PATTON, HJ AF BECK, SL PATTON, HJ TI INVERSION OF REGIONAL SURFACE-WAVE SPECTRA FOR SOURCE PARAMETERS OF AFTERSHOCKS FROM THE LOMA-PRIETA EARTHQUAKE SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID CALIFORNIA AB Surface waves recorded at regional distances are used to study the source parameters for three of the larger aftershocks of the 18 October 1989, Loma Prieta, California, earthquake. The short-period P-wave first-motion focal mechanisms indicate a complex aftershock sequence with a wide variety of mechanisms. Many of these events are too small for teleseismic body-wave analysis; therefore, the regional surface-waves provide important long-period information on the source parameters. Intermediate-period Rayleigh- and Love-wave spectra are inverted for the seismic moment tensor elements at a fixed depth and repeated for different depths to find the source depth that gives the best fit to the observed spectra. For the aftershock on 19 October at 10:14:35 (m(d) = 4.2), we find a strike-slip focal mechanism with right lateral motion on a NW-trending vertical fault consistent with the mapped trace of the local faults. For the aftershock on 18 October at 10:22:04 (m(d) = 4.4), the surface waves indicate a pure reverse fault with the nodal planes striking WNW. For the aftershock on 19 October at 09:53:50 (m(d) = 4.4), the surface waves indicate a strike-slip focal mechanism with a NW-trending vertical nodal plane consistent with the local strike of the San Andreas fault. Differences between the surface-wave focal mechanisms and the short-period P-wave first-motion mechanisms are observed for the aftershocks analyzed. This discrepancy may reflect the real variations due to differences in the band width of the two observations. However, the differences may also be due to (1) errors in the first-motion mechanism due to incorrect near-source velocity structure and (2) errors in the surface-wave mechanisms due to inadequate propagation path corrections. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT EARTH SCI,LIVERMORE,CA 94550. RP BECK, SL (reprint author), UNIV ARIZONA,DEPT GEOSCI,TUCSON,AZ 85721, USA. NR 10 TC 12 Z9 13 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD OCT PY 1991 VL 81 IS 5 BP 1726 EP 1736 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ003 UT WOS:A1991GQ00300014 ER PT J AU HUTCHINGS, L AF HUTCHINGS, L TI PREDICTION OF STRONG GROUND MOTION FOR THE 1989 LOMA-PRIETA EARTHQUAKE USING EMPIRICAL GREENS-FUNCTIONS SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID PEAK HORIZONTAL ACCELERATION; OCTOBER 18; TELESEISMIC CONSTRAINTS; LONG-PERIOD; NEAR-SOURCE; BROAD-BAND; CALIFORNIA; RUPTURE; SPECTRA; WAVE AB This article examines how the empirical Green's function seismogram synthesis method might perform as a tool for earthquake hazard analysis by "predicting" strong ground motion from the 18 October 1989 Loma Prieta earthquake. A suite of accelerograms are synthesized for five sites 40 to 80 km from the nearest fault rupture from 25 different source models that might have been considered prior to the occurrence of the Loma Prieta earthquake. Three-component, full wavetrain ground accelerations are synthesized over the frequency range of 0.5 to 25.0 Hz with a sparse distribution of source events for empirical Green's functions and fairly simple source models. The suite of source models includes a range of rupture histories and geometries, asperity models, and slip models that reflect the uncertainties both in predicting the actual rupture history and in knowledge of modeling rupture processes. The suite of synthesized accelerograms includes a good match to observed time series amplitudes, frequency content, energy distribution, and some waveforms and demonstrates that the character of actual time series can be captured with a range of simple source models. The average levels of peak acceleration, pseudo-velocity response, and Fourier amplitude spectra provide a good prediction to the observed values at four of the five sites. The log-normal standard deviations provide bounds on the predictions that are specific to the source and recording site. RP HUTCHINGS, L (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-208,LIVERMORE,CA 94550, USA. NR 66 TC 18 Z9 20 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD OCT PY 1991 VL 81 IS 5 BP 1813 EP 1837 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GQ003 UT WOS:A1991GQ00300018 ER PT J AU DOHRN, R KUNSTLER, W PRAUSNITZ, JM AF DOHRN, R KUNSTLER, W PRAUSNITZ, JM TI CORRELATION OF HIGH-PRESSURE PHASE-EQUILIBRIA IN THE RETROGRADE REGION WITH 3 COMMON EQUATIONS OF STATE SO CANADIAN JOURNAL OF CHEMICAL ENGINEERING LA English DT Article DE RETROGRADE REGION; PHASE EQUILIBRIA; EQUATION OF STATE; NATURAL GAS AB Phase equilibria in the retrograde regions were calculated for the methane - n-decane binary system and for a realistic natural-gas system (methane - Kensol-16). Calculations were performed using three equations of state (EOS): Peng-Robinson, Redlich-Kwong-Soave and Perturbed-Hard-Chain; calculations were compared to experiment. Liquid-drop-out curves and pressure-temperature diagrams were calculated between 301 and 369 K and pressures to 90 MPa. The binary system was represented best by the Peng-Robinson EOS. For the natural-gas system, the Perturbed-Hard Chain equation yielded the best results, although all equations of state showed appreciable deviations. Good results could only be obtained when binary coefficients were fitted to the experimental retrograde data. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 16 TC 1 Z9 1 U1 0 U2 2 PU CANADIAN SOC CHEMICAL ENGINEERING PI OTTAWA PA 130 SLATER ST, STE 550, OTTAWA ON K1P 6E2, CANADA SN 0008-4034 J9 CAN J CHEM ENG JI Can. J. Chem. Eng. PD OCT PY 1991 VL 69 IS 5 BP 1200 EP 1205 PG 6 WC Engineering, Chemical SC Engineering GA GN876 UT WOS:A1991GN87600021 ER PT J AU STEINMAN, AD MULHOLLAND, PJ KIRSCHTEL, DB AF STEINMAN, AD MULHOLLAND, PJ KIRSCHTEL, DB TI INTERACTIVE EFFECTS OF NUTRIENT REDUCTION AND HERBIVORY ON BIOMASS, TAXONOMIC STRUCTURE, AND P-UPTAKE IN LOTIC PERIPHYTON COMMUNITIES SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID STREAM ALGAE; GRAZING MINNOWS; PHOSPHORUS; LAKE; ENRICHMENT; LIMITATION; RESPONSES; NITROGEN; ECOSYSTEM; DYNAMICS AB Four treatments were imposed on eight laboratory streams in a factorial design to examine the roles of nutrient reduction and herbivory on periphyton communities, Treatments included two flow regimes (once-through flow or 90% recirculated water) and two levels of grazer density (1000 or 0.m-2, using the snail Elimia clavaeformis). Periphyton biomass was significantly greater in streams without snails than in those with them, but water supply had no overall significant effect on biomass, even though inorganic P and N concentrations were significantly lower in recirculated than in once-through streams. Areal-specific P uptake rates (measured with P-33) were significantly greater on two dates in no-snail streams compared with snail streams, presumably because of the greater biomass levels in the former systems. Differences in biomass-specific P uptake rates were not significantly affected by either grazer density or water supply. Relative abundances of most algal species were unaffected by the water supply treatment, although percent biovolume of two Epithemia species was greater in no-snail, recirculated than in no-snail, once-through streams. Grazing activity dramatically reduced the percent biovolume of species with upright growth forms, resulting in dominance by species with prostrate growth forms. RP STEINMAN, AD (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Mulholland, Patrick/C-3142-2012; OI Steinman, Alan/0000-0002-4886-4305 NR 58 TC 35 Z9 35 U1 3 U2 13 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD OCT PY 1991 VL 48 IS 10 BP 1951 EP 1959 DI 10.1139/f91-232 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA GL814 UT WOS:A1991GL81400018 ER PT J AU KAINA, B FRITZ, G MITRA, S COQUERELLE, T AF KAINA, B FRITZ, G MITRA, S COQUERELLE, T TI TRANSFECTION AND EXPRESSION OF HUMAN O6-METHYLGUANINE-DNA METHYLTRANSFERASE (MGMT) CDNA IN CHINESE-HAMSTER CELLS - THE ROLE OF MGMT IN PROTECTION AGAINST THE GENOTOXIC EFFECTS OF ALKYLATING-AGENTS SO CARCINOGENESIS LA English DT Article ID SISTER-CHROMATID EXCHANGES; O-6-ALKYLGUANINE-DNA ALKYLTRANSFERASE ACTIVITY; DEFICIENT HUMAN-CELLS; METHYL-N-NITROSOUREA; HUMAN LYMPHOID-CELLS; ESCHERICHIA-COLI; MAMMALIAN-CELLS; O-6-METHYLGUANINE-DNA METHYLTRANSFERASE; OVARY CELLS; DNA-REPAIR AB O6-Methylguanine-DNA methyltransferase (MGMT) is responsible for removal of O6-alkylguanine from DNA induced by alkylating mutagens/carcinogens. To analyze the involvement of O6-alkylguanine in the generation and MGMT in avoidance of various genotoxic effects of alkylating agents, we transfected Chinese hamster ovary (CHO) cells that lack MGMT activity with human MGMT cDNA cloned into a mammalian expression vector (pSV2MGMT). A high proportion (60-80%) of transfectants selected for a co-transfected neo gene survived treatment with high doses of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-hydroxyethyl-N-chloroethylnitrosourea (HeCNU). Parallel transfections with an expression vector containing the bacterial ada gene (pSV2ada) showed the human MGMT to be more effective than the ada expression vector in mediating alkylation resistance. Various clonal CHO cell lines have been established stably transfected with the human MGMT cDNA. The transfectants expressed human MGMT at levels ranging from 8600 to 210 000 molecules per cell. The high MGMT expressors became strongly resistant to the killing effects of MNNG. HeCNU, N-methyl-N-nitrosourea (MNU) and, to a significant lesser degree, methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS). No killing resistance was observed to N-ethyl-N-nitrosourea (ENU), though the MGMT and ada transfectants showed reduction in mutation frequency induced by this agent. Protection from mutation induction by MGMT (and ada) expression was also demonstrated for MNNG. The transfectants were also protected from the sister chromatid exchange (SCE) inducing and, to a lesser degree, clastogenic effect of MNNG and MNU, and slightly to EMS and MMS. Again no protection was observed towards ENU. Correlations between MGMT activity and resistance to a given end point suggest that, for MNNG, O6-methylguanine is the preponderant toxic, mutagenic and SCE inducing lesion. About 90% of MNNG (and MNU) induced SCEs and nearly all of the MNNG-induced gene mutations seem to be due to this adduct. For alkylation-induced chromosomal aberrations, however, and for cell killing and SCEs induced by MMS, EMS and ENU, other lesions than O6-alkylguanine appear to be of major importance. The data strongly support the view that O6-methylguanine is a genotoxic lesion and MGMT a function decisively involved in avoidance of genotoxic effects in cells exposed to MNNG and related compounds. They indicate also that it is important to take into account the property and mode of action of any given alkylating agent in assessing the protective role of MGMT against alkylation-induced genotoxicity. C1 OAK RIDGE NATL LAB, DIV BIOL, OAK RIDGE, TN 37831 USA. RP KAINA, B (reprint author), FORSCHUNGSZENTRUM JULICH, DEPT GENET & TOXICOL, POSTFACH 3640, W-7500 KARLSRUHE 1, GERMANY. FU NCI NIH HHS [CA 31721] NR 85 TC 228 Z9 230 U1 2 U2 3 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD OCT PY 1991 VL 12 IS 10 BP 1857 EP 1867 PG 11 WC Oncology SC Oncology GA GK259 UT WOS:A1991GK25900016 PM 1657427 ER PT J AU Hoover, WG Craig, E Posch, HA Holian, BL Hoover, CG AF Hoover, William G. Craig, Errol Posch, Harald A. Holian, Brad Lee Hoover, Carol G. TI Heat transfer between two degrees of freedom SO CHAOS LA English DT Article AB A particularly simple chaotic nonequilibrium open system with two Cartesian degrees of freedom. characterized by two distinct temperatures T-x and T-y is introduced. The two temperatures are maintained by Nose-Hoover canonical-ensemble thermostats. Both the equilibrium (no net heat transfer) and nonequilibrium (dissipative) Lyapunov spectra are characterized for this simple system. C1 [Hoover, William G.; Craig, Errol] Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. [Posch, Harald A.] Univ Vienna, Inst Expt Phys, A-1090 Vienna, Austria. [Holian, Brad Lee] Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. [Hoover, Carol G.] Natl Energy Res Supercomp Ctr, Livermore, CA 94550 USA. RP Hoover, WG (reprint author), Univ Calif Davis, Dept Appl Sci, POB 808, Livermore, CA 94550 USA. FU Lawrence Livermore National Laboratory under University of California-Department of Energy [W-7405-Eng-48]; Los Alamos National Laboratory under University of California-Department of Energy [W-7405-Eng-36]; Fonds zur Foerderung der Wissenschaftlichen Forschung [PS003]; Academy of Applied Science FX Work carried out at the Lawrence Livermore National Laboratory was performed under University of California-Department of Energy Contract W-7405-Eng-48; work performed at the Los Alamos National Laboratory was performed under University of California-Department of Energy Contract W-7405-Eng-36. Work carried out at the University of Vienna, within the IBM European Supercomputer Initiative, was supported by the Fonds zur Foerderung der Wissenschaftlichen Forschung, project PS003. Errol Craig was supported by a grant from the Academy of Applied Science. William Hoover would like to thank the National Science Foundation for generous travel support and to thank Professor Cohen for a preprint copy of Ref. S. NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1054-1500 J9 CHAOS JI Chaos PD OCT PY 1991 VL 1 IS 3 PG 3 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA V22XL UT WOS:000208307800011 ER PT J AU SUSSKIND, H WEBER, DA VOLKOW, ND HITZEMANN, R AF SUSSKIND, H WEBER, DA VOLKOW, ND HITZEMANN, R TI INCREASED LUNG PERMEABILITY FOLLOWING LONG-TERM USE OF FREE-BASE COCAINE (CRACK) SO CHEST LA English DT Article ID PULMONARY EPITHELIAL PERMEABILITY; SMOKING; CLEARANCE; DISEASE; ABUSE; EDEMA AB The clearance of inhaled Tc-99m DTPA aerosol from the lungs is used as an index of lung epithelial permeability. Using the radioaerosol method, we investigated the effects of long-term "crack" (free-base cocaine) inhalation on lung permeability in 23 subjects. Eighteen control subjects (12 nonsmokers and 6 cigarette smokers) with no history of drug use were also studied. Subjects inhaled approximately 150-mu-Ci (approximately 5.6 MBq) of Tc-99m DTPA aerosol and quantitative gamma camera images of the lungs were acquired at 1-min increments for 25 minutes. Regions of interest (ROIs) were selected to include the following: (1) both lungs; (2) each individual lung; and (3) the upper, middle, and lower thirds of each lung. Tc-99m DTPA lung clearance was determined from the slopes of the respective time-activity plots for the different ROIs. Radioaerosol clearance half-times (T1/2) for the seven nonsmoking crack users (61.5 +/- 18.3 minutes) were longer than for the seven cigarette-smoking crack users (27.9 +/- 16.9 minutes) and nine cigarette-smoking crack plus marijuana users (33.5 +/- 21.6 minutes). T1/2 for the nonsmoking crack users was significantly shorter (p < 0.001) than for the nonsmoking control group (123.8 +/- 28.7 minutes). T1/2 for the cigarette-smoking drug users was similar to that of the cigarette-smoking control group (33.1 +/- 17.8 minutes), suggesting a similar mechanism of damage from the smoke of crack and tobacco. From these groups, one nonsmoker and 11 cigarette smokers displayed biexponential Tc-99m DTPA clearances, indicative of greater lung injury than found in the usual cases of monoexponential clearance. The upper lungs of all crack user groups cleared faster than the lower lungs. The faster and biexponential clearance properties of inhaled Tc-99m DTPA aerosol were the principal functional abnormalities found in all the drug users. In contrast, 19 of 23 crack users had normal spirometry and gas exchange. These results indicate that Tc-99m DTPA may provide a sensitive and useful assay to evaluate the physiologic effects of cocaine inhalation in the lung. C1 VET ADM MED CTR,DEPT PSYCHIAT,NORTHPORT,NY 11768. RP SUSSKIND, H (reprint author), BROOKHAVEN NATL LAB,CLIN RES CTR,UPTON,NY 11973, USA. NR 23 TC 44 Z9 46 U1 0 U2 1 PU AMER COLL CHEST PHYSICIANS PI NORTHBROOK PA 3300 DUNDEE ROAD, NORTHBROOK, IL 60062-2348 SN 0012-3692 J9 CHEST JI Chest PD OCT PY 1991 VL 100 IS 4 BP 903 EP 909 DI 10.1378/chest.100.4.903 PG 7 WC Critical Care Medicine; Respiratory System SC General & Internal Medicine; Respiratory System GA GK147 UT WOS:A1991GK14700006 PM 1914604 ER PT J AU GOLDSTEIN, SJ MURRELL, MT JANECKY, DR DELANEY, JR CLAGUE, DA AF GOLDSTEIN, SJ MURRELL, MT JANECKY, DR DELANEY, JR CLAGUE, DA TI GEOCHRONOLOGY AND PETROGENESIS OF MORB FROM THE JUAN DE FUCA AND GORDA RIDGES BY U-238 TH-230 DISEQUILIBRIUM SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article ID EAST PACIFIC RISE; DE-FUCA; SPREADING CENTERS; GABBROIC XENOLITHS; ND ISOTOPES; HALF-LIFE; BASALTS; SYSTEMATICS; SR; GEOCHEMISTRY AB A highly precise mass spectrometric method of analysis was used to determine U-238-U-234-Th-230-Th-232 in axial and off-axis basalt glasses from Juan de Fuca (JDF) and Gorda ridges. Initial Th-230 activity excesses in the axial samples range from 3 to 38%, but generally lie within a narrow range of 12 to 15%. Secondary alteration effects were evaluated using delta-U-234 and appear to be negligible; hence the Th-230 excesses are magmatic in origin. Direct dating of MORB was accomplished by measuring the decrease in excess Th-230 in off-axis samples. U-238-Th-230 ages progressively increase with distance from axis. Uncertainties in age range from 10 to 25 ka for U-Th ages of 50 to 200 ka. The full spreading rate based on U-Th ages for Endeavour segment of JDF is 5.9 +/- 1/2 cm/yr, with asymmetry in spreading between the Pacific (4.0 +/- 0.6 cm/yr) and JDF (1.9 +/- 0.6 cm/yr) plates. For northern Gorda ridge, the half spreading rate for the JDF plate is found to be 3.0 +/- 0.4 cm/yr. These rates are in agreement with paleomagnetic spreading rates and topographic constraints. This suggests that assumptions used to determine ages, including constancy of initial Th-230/Th-232 ratio over time, are generally valid for the areas studied. Samples located near the axis of spreading are typically younger than predicted by these spreading rates, which most likely reflects recent volcanism within a 1-3 km wide zone of crustal accretion. Initial Th-230/Th-232 ratios and Th-230 activity were also used to examine the recent Th/U evolution and extent of melting of mantle sources beneath these ridges. A negative anomaly in Th-230/Th-232 for Axial seamount lavas provides the first geochemical evidence of a mantle plume source for Axial seamount and the Cobb-Eickelberg seamount chain and indicates recent depletion of other JDF segment sources. Large Th-230 activity excesses for lavas from northern Gorda ridge and Endeavour segment indicate formation from a lower degree of partial melting than other segments. An inverse correlation between Th-230 excess and Th-230/Th-232 for each ridge indicates that these lower degree melts formed from slightly less depleted sources than higher degree melts. Uniformity in Th-230 excess for other segments suggests similarity in processes of melt formation and mixing beneath most of the JDF-Gorda ridge area. The average initial Th-230/Th-232 activity ratio of 1.31 for the JDF-Gorda ridge area is in agreement with the predicted value of 1.32 from the Th-Sr isotope mantle array. C1 US GEOL SURVEY,MENLO PK,CA 94025. UNIV WASHINGTON,SCH OCEANOG,SEATTLE,WA 98195. RP GOLDSTEIN, SJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,ISOTOPE GEOCHEM GRP INC-7,LOS ALAMOS,NM 87545, USA. NR 44 TC 64 Z9 64 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD OCT PY 1991 VL 107 IS 1 BP 25 EP 41 DI 10.1016/0012-821X(91)90041-F PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GR200 UT WOS:A1991GR20000003 ER PT J AU DALE, VH FRANKLIN, RLA POST, WM GARDNER, RH AF DALE, VH FRANKLIN, RLA POST, WM GARDNER, RH TI SAMPLING ECOLOGICAL INFORMATION - CHOICE OF SAMPLE-SIZE SO ECOLOGICAL MODELLING LA English DT Article ID SIMILARITY AB Factors that significantly affect sample statistics obtained from ecological measurements need to be identified. We used a computer simulation to examine the effects of sample size on the mean and variance for four frequency distributions of the attribute of interest. The kurtosis of the underlying distribution affects fluctuations in the sample mean as the number of samples increases. For large sample sizes, the sample mean of the lognormal distribution is less than the population mean because of the skewness of that distribution. The standard error-to-mean ratio, kurtosis and skewness can be used as guides to suggest the appropriate number of samples to adequately characterize the true distribution. RP DALE, VH (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Dale, Virginia/B-6023-2009; Post, Wilfred/B-8959-2012 NR 16 TC 5 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD OCT 1 PY 1991 VL 57 IS 1-2 BP 1 EP 10 DI 10.1016/0304-3800(91)90051-2 PG 10 WC Ecology SC Environmental Sciences & Ecology GA GP698 UT WOS:A1991GP69800001 ER PT J AU DEANGELIS, DL GODBOUT, L SHUTER, BJ AF DEANGELIS, DL GODBOUT, L SHUTER, BJ TI AN INDIVIDUAL-BASED APPROACH TO PREDICTING DENSITY-DEPENDENT DYNAMICS IN SMALLMOUTH BASS POPULATIONS SO ECOLOGICAL MODELLING LA English DT Article ID TEMPERATURE; SIZE; RECRUITMENT; FISHES; MODEL; LAKE AB The dynamics of a young-of-the-year cohort of a fish species, smallmouth bass (Micropterus dolomieui), were modeled using an individual-based computer simulation model. The young-of-the-year fish were simulated from the egg stage until recruitment into the yearling age class. At low initial densities of smallmouth bass in the swim-up larvae stage, recruitment to the yearling age class was roughly proportional to the initial densities of larval fish. However, when the initial densities were sufficiently high decreasing recruitment was observed as a function of further increases in larval density in the model. This occurred because high initial densities prevented all but a small fraction of the smallmouth bass from attaining large enough sizes to escape winter starvation. The addition of significant levels of size-dependent predation greatly altered this result, however. Heavy predation reduced the competition for prey among smallmouth bass and allowed a large number of smallmouth bass to grow rapidly and recruit to the yearling class. C1 ONTARIO MINIST NAT RESOURCES,FISHERIES BRANCH,MAPLE L0J 1E0,ONTARIO,CANADA. RP DEANGELIS, DL (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Shuter, Brian/A-3991-2008 NR 32 TC 76 Z9 78 U1 2 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD OCT 1 PY 1991 VL 57 IS 1-2 BP 91 EP 115 DI 10.1016/0304-3800(91)90056-7 PG 25 WC Ecology SC Environmental Sciences & Ecology GA GP698 UT WOS:A1991GP69800006 ER PT J AU KENNY, D LOEHLE, C AF KENNY, D LOEHLE, C TI ARE FOOD WEBS RANDOMLY CONNECTED SO ECOLOGY LA English DT Article DE COMBINATORICS; CONNECTANCE; EXPECTED DISTRIBUTION; FOOD WEB TOPOLOGY; NULL MODEL; SAMPLING BIAS; TROPHIC INTERACTIONS ID TEMPORAL VARIATION; CHAIN LENGTH; STABILITY; PATTERNS; MODELS AB We present a simple random model for food web connectance. We model observed webs as random samples drawn from the universe of all possible randomly connected sets of n objects, with no biological interactions assumed. We then drop out links based on observed link-magnitude data and sampling effects. The resulting connectance curves nicely bracket real data, suggesting (1) that food webs may in fact be randomly connected, and (2) the mere fact that previously proposed models can generate the observed connectance values does not guarantee the correctness of the models. This study also suggests that studies of food web topological properties may bear reexamination. C1 UNIV TENNESSEE,GRAD PROGRAM ECOL,KNOXVILLE,TN 37996. WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER LAB,ENVIRONM SCI SECT,AIKEN,SC 29808. NR 22 TC 29 Z9 32 U1 0 U2 3 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD OCT PY 1991 VL 72 IS 5 BP 1794 EP 1799 DI 10.2307/1940978 PG 6 WC Ecology SC Environmental Sciences & Ecology GA GK823 UT WOS:A1991GK82300026 ER PT J AU MARLAND, G AF MARLAND, G TI THE GREENHOUSE INDEX SO ENVIRONMENT LA English DT Editorial Material RP MARLAND, G (reprint author), OAK RIDGE NATL LAB,SERV ENVIRONM SCI,OAK RIDGE,TN 37830, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU HELDREF PUBLICATIONS PI WASHINGTON PA 1319 EIGHTEENTH ST NW, WASHINGTON, DC 20036-1802 SN 0013-9157 J9 ENVIRONMENT JI Environment PD OCT PY 1991 VL 33 IS 8 BP 2 EP 4 PG 3 WC Environmental Sciences; Environmental Studies SC Environmental Sciences & Ecology GA GJ987 UT WOS:A1991GJ98700002 ER PT J AU MCKONE, TE BOGEN, KT AF MCKONE, TE BOGEN, KT TI PREDICTING THE UNCERTAINTIES IN RISK ASSESSMENT - A CALIFORNIA GROUNDWATER CASE-STUDY SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID VOLATILE ORGANIC-COMPOUNDS; EXPOSURE; WATER; TETRACHLOROETHYLENE; TRICHLOROETHYLENE; MODELS RP MCKONE, TE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DIV ENVIRONM SCI, LIVERMORE, CA 94550 USA. NR 34 TC 94 Z9 95 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X EI 1520-5851 J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD OCT PY 1991 VL 25 IS 10 BP 1674 EP 1681 DI 10.1021/es00022a002 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA GH491 UT WOS:A1991GH49100004 ER PT J AU PONS, ME DIAZ, A LACKS, SA LOPEZ, P AF PONS, ME DIAZ, A LACKS, SA LOPEZ, P TI THE POLYMERASE DOMAIN OF STREPTOCOCCUS-PNEUMONIAE DNA-POLYMERASE-I - HIGH EXPRESSION, PURIFICATION AND CHARACTERIZATION SO EUROPEAN JOURNAL OF BIOCHEMISTRY LA English DT Article ID POLYACRYLAMIDE-GEL-ELECTROPHORESIS; ESCHERICHIA-COLI; KLENOW FRAGMENT; RNA-POLYMERASE; PLASMID; BACTERIOPHAGE-T7; REPLICATION; SITES; GENES AB The 3'-terminal two-thirds of the Streptococcus pneumoniae polA gene was cloned in an Escherichia coli genefusion vector with inducible expression. The resulting recombinant plasmid (pSM10) directs the hyperproduction of a polypeptide of 70.6 kDa corresponding to the C-terminal fragment of pneumococcal DNA polymerase I. Induced cells synthesized catalytically active protein to the extent of 7% of the total soluble protein in the cells. The polymerase fragment was purified to greater than 90% homogeneity with a yield of 1.5 mg pure protein/l culture. The protein has DNA polymerase activity, but no exonuclease activity. The enzyme requires a divalent cation (MgCl2 or MnCl2) for polymerization of DNA. Comparison of the mutant and wild-type pneumococcal polymerases shows that the construction did not affect the enzymatic affinity for the various substrates. The mutant protein, like its parent DNA polymerase I, exhibited an intermediate level of activity with primed single-stranded DNA. At high molar ratio of enzyme/DNA substrate, the polymerase fragment catalyzes strand displacement and switching after completing the replication of a primed single-stranded M13 DNA molecule. C1 CTR INVEST BIOL,VELAZQUEZ 144,E-28006 MADRID,SPAIN. BROOKHAVEN NATL LAB,UPTON,NY 11973. RI Lopez Garcia, Paloma/L-1583-2014 OI Lopez Garcia, Paloma/0000-0001-8755-8952 FU NIAID NIH HHS [AI14885]; NIGMS NIH HHS [GM29721] NR 26 TC 11 Z9 11 U1 0 U2 1 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 OCT 1 PY 1991 VL 201 IS 1 BP 147 EP 155 DI 10.1111/j.1432-1033.1991.tb16267.x PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GG925 UT WOS:A1991GG92500016 PM 1915357 ER PT J AU SCHULTZ, DL AF SCHULTZ, DL TI PARENTAL INVESTMENT IN TEMPORALLY VARYING ENVIRONMENTS SO EVOLUTIONARY ECOLOGY LA English DT Article DE PARENTAL INVESTMENT; EGG SIZE; ENVIRONMENTAL UNCERTAINTY; PHENOTYPIC VARIANCE; LIFE HISTORY VARIATION AB Using a model that allows the mean and variance of investment by parents in offspring to evolve in response to change in degree of temporal environmental variation, this paper shows that both parental investment parameters should increase with increases in temporal variation. If offspring receiving greater parental investment are viable over a broader range of environmental conditions, then increased temporal environmental variation can select for increases in parental investment. The variance in parental investment also may increase with increases in temporal variation, but there is a threshold level of temporal variation that must be exceeded before variance in parental investment is adaptive. Thus phenotypic variance in parental investment is not adaptive in all temporally varying environments. Further, increased overlap among generations reduces the expected effects of temporal variation on the mean and variance in parental investment. Thus a negative correlation between length of reproductive life and both measures of investment is expected. There is support for the predictions of this model in some animal groups, but not among plants. Possible reasons for the lack of support among plants are discussed and directions for future research aimed at distinguishing adaptive and maladaptive phenotypic variance in parental investment are suggested. RP SCHULTZ, DL (reprint author), UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29801, USA. NR 0 TC 30 Z9 30 U1 0 U2 5 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0269-7653 J9 EVOL ECOL JI Evol. Ecol. PD OCT PY 1991 VL 5 IS 4 BP 415 EP 427 DI 10.1007/BF02214158 PG 13 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA GM086 UT WOS:A1991GM08600007 ER PT J AU NEBEN, S REDFEARN, WJ PARRA, M BRECHER, G PALLAVICINI, MG AF NEBEN, S REDFEARN, WJ PARRA, M BRECHER, G PALLAVICINI, MG TI SHORT-TERM AND LONG-TERM REPOPULATION OF LETHALLY IRRADIATED MICE BY BONE-MARROW STEM-CELLS ENRICHED ON THE BASIS OF LIGHT SCATTER AND HOECHST-33342 FLUORESCENCE SO EXPERIMENTAL HEMATOLOGY LA English DT Article DE HEMATOPOIETIC STEM CELLS; ENRICHMENT; SURVIVAL; LONG-TERM REPOPULATION; HOECHST-33342 ID COLONY-FORMING CELLS; W/W-NU MICE; CFU-S CELL; SELF-RENEWAL; SEPARATION; MOUSE; NUMBERS; SPLEEN; 5-FLUOROURACIL; MOSAICISM AB Murine bone marrow subpopulations enriched in hemopoietic stem cells were transfused into lethally irradiated hosts to determine the contribution of host cells and two types of donor cells to marrow repopulation. Donor cell suspension were a mixture of marrows from two congenic lines of mice containing electrophoretically distinguishable alloenzymes of phosphoglycerate kinase (PGK-A and PGK-B). The donor cells were sorted by high forward light scatter, low-to-intermediate perpendicular light scatter, and low Hoechst 33342 fluorescence intensity. The congenic hosts contained a third distinct marker, glucose phosphate isomerase (GPI-A). The two markers in the donor cells allowed determination of the clones generated by the seeded cells over a 36-week period of observation. The clone number declined rapidly during the first 12 weeks following transplantation and reached stable levels at 20 weeks, indicating the number of long-term repopulating cells (LTRC). The sorted subpopulation was enriched 170-fold for day-13 spleen colony-forming units (CFU-S), 235-fold for cells providing a 30-day survival, and 136- to 160-fold for LTRC. Survival for the 36-week observation period was 40%-100% for groups of hosts receiving 100-3000 sorted cells and 80% for controls receiving 2 x 10(5) unsorted cells. In all groups, similar distribution of phenotypes among peripheral blood erythrocytes, platelets, and lymphocytes at 36 weeks suggested that the repopulating donor stem cells were pluripotential. Transfusion of 3000 sorted cells, containing about 5 LTRC and 60 CFU-S, assured continuous repopulation with 95%-100% donor cells 4 to 36 weeks after transplantation, whereas significant numbers of host cells re-emerged temporarily or permanently when lower numbers of LTRC and CFU-S were transfused. The data indicate that both the quality and quantity of pluripotential stem cells in sorted bone marrow are important for complete long-term marrow reconstitution. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. UNIV CALIF BERKELEY,PROGRAM BIOSTAT,BERKELEY,CA 94720. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. FU NCI NIH HHS [CA44047]; NIDDK NIH HHS [DK27454] NR 32 TC 55 Z9 54 U1 0 U2 0 PU CARDEN JENNINGS PUBL CO LTD PI CHARLOTTESVILLE PA BLAKE CTR, STE 200, 1224 W MAIN ST, CHARLOTTESVILLE, VA 22903 SN 0301-472X J9 EXP HEMATOL JI Exp. Hematol. PD OCT PY 1991 VL 19 IS 9 BP 958 EP 967 PG 10 WC Hematology; Medicine, Research & Experimental SC Hematology; Research & Experimental Medicine GA GH135 UT WOS:A1991GH13500019 PM 1893973 ER PT J AU MORRIS, JS BYERS, CH AF MORRIS, JS BYERS, CH TI NEAR-CRITICAL-REGION EQUILIBRIA OF THE CH4-CO2-H2S SYSTEM SO FLUID PHASE EQUILIBRIA LA English DT Article ID LIQUID-VAPOR EQUILIBRIA; CARBON-DIOXIDE; EQUATION; STATE; METHANE AB To acquire data for assessing a proposed syngas purification system, an apparatus has been built to measure vapor-liquid equilibria of binary and multicomponent systems in the critical region of CH4-CO2-H2S mixtures. To test the experimental device and supplement existing data, binary systems were studied between 270.0 and 288.2 K. Predictions of the Peng-Robinson (PR) and Redlich-Kwong-Soave (RKS) equations of state were compared with binary and ternary data using the ASPEN simulator parameter regression utilities to determine binary interaction parameters from binary data. Calculated phase equilibria for CH4-CO2 mixtures based on both equations agree to within 3.5%, while the difference in either case with experimental liquid phase compositions is less than 15%. Similar results were obtained for CO2-H2S mixtures. Experimental values were less reliable for CH4-H2S binary interaction parameters. In predicting the ternary mixtures, total pressure is generated using both equations of state. Estimates by the PR equation were significantly better than those generated by the RKS equation (12% deviation versus 29% deviation) for the temperature and pressure range of the study. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. NR 24 TC 5 Z9 5 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD OCT 1 PY 1991 VL 66 IS 3 BP 291 EP 308 DI 10.1016/0378-3812(91)85062-Y PG 18 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA GK695 UT WOS:A1991GK69500005 ER PT J AU FRYBERGER, D AF FRYBERGER, D TI COULOMB SCATTERING OF AN ELECTRON BY A MONOPOLE SO FOUNDATIONS OF PHYSICS LETTERS LA English DT Article DE CLIFFORD ALGEBRA; ELECTRON-MONOPOLE SCATTERING; MAGNETIC MONOPOLES AB The Coulomb scattering of an electron by a magnetic monopole is analyzed using a lowest-order quantum perturbation approximation suggested by a two-potential Lagrangian form for classical electromagnetism, generalized through the use of spacetime algebra to include magnetic monopoles. Good agreement with existing conventional analyses of this problem is demonstrated. RP FRYBERGER, D (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0894-9875 J9 FOUND PHYS LETT JI Found. Phys. Lett. PD OCT PY 1991 VL 4 IS 5 BP 459 EP 464 DI 10.1007/BF00691191 PG 6 WC Physics, Multidisciplinary SC Physics GA GP536 UT WOS:A1991GP53600005 ER PT J AU KRISHNAN, RP ANTHONY, J RAJAVEL, M SRINIVASAN, SV RAO, AVJ AF KRISHNAN, RP ANTHONY, J RAJAVEL, M SRINIVASAN, SV RAO, AVJ TI COMBUSTION OF HIGH ASH INDIAN COALS IN A FLUIDIZED-BED COMBUSTOR SO FUEL LA English DT Article DE ASH; COAL; COMBUSTION AB High ash Indian subbituminous coal and coal washery rejects were burned in a 1 m x 1 m fludized bed combustion (FBC) test facility at the Bharat Heavy Electricals plant in Trichy, India. Freeboard combustion and heat transfer were measured with the aim of improving the design database for large FBC boilers. Observed freeboard combustion levels were 10-15% for overbed feed and 6-10% for underbed feed. The results indicate that, even with high ash Indian coal, it is possible to achieve overall combustion efficiencies of up to 97% if sufficient bed temperature and excess air are utilized. Overall combustion efficiencies of 98% are possible with flyash recycle. The heat transfer coefficient in the bed was in the range 193-300 kcal (h m2-degrees-C)-1. In the freeboard, the coefficient ranged from 137-168 kcal (h m2-degrees-C)-1 close to the bed surface and decreased exponentially at the higher elevations. C1 BHARAT HEAVY ELECT LTD,TIRUCHCHIRAPPALLI 620014,INDIA. RP KRISHNAN, RP (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 34 TC 4 Z9 4 U1 0 U2 1 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0016-2361 J9 FUEL JI Fuel PD OCT PY 1991 VL 70 IS 10 BP 1125 EP 1135 DI 10.1016/0016-2361(91)90232-Y PG 11 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA GH021 UT WOS:A1991GH02100002 ER PT J AU MERRILL, BJ JARDIN, SC ULRICKSON, M BELL, M AF MERRILL, BJ JARDIN, SC ULRICKSON, M BELL, M TI DYNAMICS AND ENERGY-FLOW IN A DISRUPTING TOKAMAK PLASMA SO FUSION ENGINEERING AND DESIGN LA English DT Article ID MODEL AB This article contains a description of our effort to apply a recently developed tokamak disruption modeling code, DSTAR, to describe in some detail the dynamic evolution of a disrupting plasma in the TFTR experiment. The physical phenomena modeled in DSTAR, and two important new extensions of this model, those of hyper-resistivity and a plasma halo, are reviewed in this paper. We also present some data taken during one of the most rapid disruptions in TFTR and present the results of comparison of this data with predictions from the DSTAR code. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP MERRILL, BJ (reprint author), EG&G IDAHO INC,POB 1625,IDAHO FALLS,ID 83415, USA. RI Jardin, Stephen/E-9392-2010 NR 12 TC 10 Z9 10 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD OCT PY 1991 VL 15 IS 2 BP 163 EP 180 DI 10.1016/0920-3796(91)90223-D PG 18 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GT433 UT WOS:A1991GT43300007 ER PT J AU CHESSER, RK AF CHESSER, RK TI INFLUENCE OF GENE FLOW AND BREEDING TACTICS ON GENE DIVERSITY WITHIN POPULATIONS SO GENETICS LA English DT Article ID TAILED PRAIRIE DOG; F-STATISTICS; SUBDIVIDED POPULATIONS; MAMMALS; FREQUENCIES; MODEL AB Expressions describing the accumulation of gene correlations within and among lineages and individuals of a population are derived. The model permits different migration rates by males and females and accounts for various breeding tactics within lineages. The resultant equations enable calculation of the probabilistic quantities for the fixation indices, rates of loss of genetic variation, accumulation of inbreeding, and coefficients of relationship for the population at any generation. All fixation indices were found to attain asymptotic values rapidly despite the consistent loss of genetic variation and accumulation of inbreeding within the population. The time required to attain asymptotic values, however, was prolonged when gene flow among lineages was relatively low (< 20%). The degree of genetic differentiation among breeding groups, inbreeding coefficients, and gene correlations within lineages were found to be primarily functions of breeding tactics within groups rather than gene flow among groups. Thus, the asymptotic value of S. Wright's island model is not appropriate for describing genetic differences among groups within populations. An alternative solution is provided that under limited conditions will reduce to the original island model. The evolution of polygynous breeding tactics appears to be more favorable for promoting intragroup gene correlations than modifications of migration rates. Inbreeding and variance effective sizes are derived for populations that are structured by different migration and breeding tactics. Processes that reduce the inbreeding effective population size result in a concomitant increase in variance effective population size. C1 UNIV GEORGIA,DEPT GENET,ATHENS,GA 30602. RP CHESSER, RK (reprint author), UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802, USA. NR 44 TC 195 Z9 197 U1 2 U2 13 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 SN 0016-6731 J9 GENETICS JI Genetics PD OCT PY 1991 VL 129 IS 2 BP 573 EP 583 PG 11 WC Genetics & Heredity SC Genetics & Heredity GA GH445 UT WOS:A1991GH44500022 PM 1743493 ER PT J AU KING, JS MORTIMER, RK AF KING, JS MORTIMER, RK TI A MATHEMATICAL-MODEL OF INTERFERENCE FOR USE IN CONSTRUCTING LINKAGE MAPS FROM TETRAD DATA SO GENETICS LA English DT Article ID MAXIMUM-LIKELIHOOD ESTIMATION; GENETIC-MAP; SACCHAROMYCES-CEREVISIAE AB In determining genetic map distances it is necessary to infer crossover frequencies from the ratios of recombinant and parental progeny. To do this accurately, in intervals where multiple crossovers may occur, a mathematical model of chiasma interference must be assumed when mapping in organisms displaying such interference. In Saccharomyces cerevisae the model most frequently used is that of R. W. Barratt. An alternative to this model is presented. This new model is implemented using a microcomputer and standard numerical methods. It is demonstrated to fit ranked tetrad data from Saccharomyces more closely than the Barratt model and thus generates more accurate estimates of map distances when used with two-point data. A computer program implementing the model has been developed for use in calculating map distances from tetrad data in Saccharomyces. C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,DIV GENET,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELLULAR & MOLEC BIOL,BERKELEY,CA 94720. RP KING, JS (reprint author), UNIV CALIF BERKELEY,GRAD GRP BIOPHYS,BERKELEY,CA 94720, USA. FU NCRR NIH HHS [5 P40 RR04231-02]; NIEHS NIH HHS [ES07075]; NIGMS NIH HHS [GM30990] NR 16 TC 14 Z9 14 U1 0 U2 1 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 SN 0016-6731 J9 GENETICS JI Genetics PD OCT PY 1991 VL 129 IS 2 BP 597 EP 602 PG 6 WC Genetics & Heredity SC Genetics & Heredity GA GH445 UT WOS:A1991GH44500024 PM 1743495 ER PT J AU SEVERSON, KJ JOHNSTONE, DL KELLER, CK WOOD, BD AF SEVERSON, KJ JOHNSTONE, DL KELLER, CK WOOD, BD TI HYDROGEOLOGIC PARAMETERS AFFECTING VADOSE-ZONE MICROBIAL DISTRIBUTIONS SO GEOMICROBIOLOGY JOURNAL LA English DT Article DE HYDROGEOLOGY; METABOLIC DIVERSITY; SUBSURFACE BACTERIA; SUBSURFACE MICROBIOLOGY; VADOSE; UNSATURATED ID DEEP SUBSURFACE SEDIMENTS; 2 SASKATCHEWAN TILLS; CLAYEY TILL; SPATIAL VARIABILITY; INORGANIC CARBON; BACTERIA; SOIL; AQUIFER; DIVERSITY; HYDROGEOCHEMISTRY AB The vadose zone and its contaminant-attenuating processes are physically interposed between surface contamination and groundwater supplies. Given the potential role of microorganisms in mediating vadose-zone chemical processes, it is vital to understand vadose microbial distributions and factors controlling those distributions. Vadose and shallow saturated zone sediments obtained from cores drilled to approximately 8 m below the surface at two hydrogeologically contrasting sites, named Dalmeny and Washington State University (WSU), were examined for culturable heterotrophic bacteria, total organic carbon (TOC), and sediment texture. Pore-water elutions were analyzed for dissolved organic carbon, sulfate, and inorganic nitrogen species. Numbers of cultured bacteria (10(3)-10(7) g-1) generally decreased with depth at both sites. The TOC decreased uniformly with depth at WSU where soil processes are the sole carbon source; at Dalmeny, where both soil and kerogen carbon are present, TOC was higher and relatively constant with depth. Numbers of distinct colony types at Dalmeny did not decline below the solum. Bacteria at Dalmeny were more numerous, exhibited greater numbers of colony types, and were metabolically more flexible than those at WSU. The smooth decline of numbers with depth at WSU paralleled and may be caused by the TOC decline with distance from a solum source. Sediment permeability and pore-water flux did not control bulk populations as suggested in previous studies, this may be explained by bacterial residence on fracture surfaces in low-permeability materials. Psychrotolerant organisms did not appear to be as abundant as mean ambient temperatures might suggest. C1 WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP SEVERSON, KJ (reprint author), DELTA ENVIRONM CONSULTANTS INC, ST PAUL, MN 55112 USA. RI Keller, C/B-3205-2012; Wood, Brian/K-4025-2012; Wood, Brian/J-8362-2013 OI Wood, Brian/0000-0003-3152-7852; Wood, Brian/0000-0003-3152-7852 NR 49 TC 7 Z9 7 U1 1 U2 3 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0149-0451 J9 GEOMICROBIOL J JI Geomicrobiol. J. PD OCT-DEC PY 1991 VL 9 IS 4 BP 197 EP 216 PG 20 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA JJ184 UT WOS:A1991JJ18400002 ER PT J AU PHILLIPS, WS FEHLER, MC AF PHILLIPS, WS FEHLER, MC TI TRAVELTIME TOMOGRAPHY - A COMPARISON OF POPULAR METHODS SO GEOPHYSICS LA English DT Article ID SEISMIC TOMOGRAPHY; ALGEBRAIC RECONSTRUCTION; INVERSION; ALGORITHM; VELOCITY AB Noisy or inconsistent traveltime data yield tomographic images that contain geologically unrealistic fluctuations. In addition to diverting attention away from structural patterns, these high-wavenumber fluctuations can generate shadow zones and caustics that destabilize iterative solution schemes requiring ray tracing. We evaluated the performance of a number of popular methods that have been designed to reduce this effect, using synthetic crosswell data containing Gaussian noise. Quantitative comparisons between tomography methods were based on the misfit with the true model, solution stability under different sets of noise of the same level, and resolution-covariance relationships. Other important factors included versatility and simplicity. Versatility is the ability to treat data with a wide range of noise levels as well as data generated by different structures. Simplicity is characterized by the number of adjustable inputs such as smoother shape, starting model, and damping or regularization parameters that may be required. Constraint parameters such as damping must be chosen before performing an inversion. The smallest-misfits between solutions and true models were found for constraint parameters lying just below a "kink" or change in slope of the rms residual versus constraint parameter curve. The kink separates regions in which either data or smoothing constraints dominate the solution and provides a means for choosing the optimal constraint parameter. A first difference regularization method performed the best overall and proved both simple to use and versatile in terms of the range of noise levels for which it could be used effectively. Second difference schemes were not tested since the problem is singular in the limited coverage crosswell geometries that we used. Convolutional quelling proved the best of the damped least-squares methods, but had resolution limited by the dimension and shape of the smoothing function. A simple averaging smoother worked reasonably well on data generated by a smooth model, while a median smoother performed better on data generated by a model with large contrasts. An iterative L1 norm method did not function well with Gaussian noise, but was effective in tests with long-tailed noise distributions. RP PHILLIPS, WS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & SPACE SCI,GEOL ENGN GRP,LOS ALAMOS,NM 87544, USA. NR 32 TC 62 Z9 66 U1 0 U2 1 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD OCT PY 1991 VL 56 IS 10 BP 1639 EP 1649 DI 10.1190/1.1442974 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GL293 UT WOS:A1991GL29300012 ER PT J AU HARRIS, DB JARPE, SP HARBEN, PE AF HARRIS, DB JARPE, SP HARBEN, PE TI SEISMIC NOISE CANCELLATION IN A GEOTHERMAL-FIELD SO GEOPHYSICS LA English DT Note RP HARRIS, DB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-205,POB 808,LIVERMORE,CA 94550, USA. NR 5 TC 1 Z9 2 U1 0 U2 2 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD OCT PY 1991 VL 56 IS 10 BP 1677 EP 1680 DI 10.1190/1.1442979 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA GL293 UT WOS:A1991GL29300017 ER PT J AU GLADNEY, ES JONES, EA NICKELL, EJ ROELANDTS, I AF GLADNEY, ES JONES, EA NICKELL, EJ ROELANDTS, I TI 1988 COMPILATION OF ELEMENTAL CONCENTRATION DATA FOR USGS DTS-1, G-1, PCC-1 AND W-1 SO GEOSTANDARDS NEWSLETTER LA English DT Article ID RARE-EARTH ELEMENTS AB Concentration data on up to 91 individual constituents in USGS DTS-1, G-1, PCC-1, and W-1 have been collected from 1647 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as +/- one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS). C1 UNIV LIEGE,B-4000 SART,BELGIUM. RP GLADNEY, ES (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,HLTH & ENVIRONM CHEM GRP,MS K-484,LOS ALAMOS,NM 87545, USA. NR 12 TC 50 Z9 50 U1 0 U2 1 PU GEOSTANDARDS PI VANDOEUVRE NANCY PA 15 RUE NOTRE-DAME-DES-PAUVRES BP 20, 54501 VANDOEUVRE NANCY, FRANCE SN 0150-5505 J9 GEOSTANDARD NEWSLETT JI Geostand. Newsl. PD OCT PY 1991 VL 15 IS 2 BP 199 EP 396 DI 10.1111/j.1751-908X.1991.tb00114.x PG 198 WC Geosciences, Multidisciplinary SC Geology GA GP288 UT WOS:A1991GP28800005 ER PT J AU JAROSEWICH, E BOATNER, LA AF JAROSEWICH, E BOATNER, LA TI RARE-EARTH ELEMENT REFERENCE SAMPLES FOR ELECTRON-MICROPROBE ANALYSIS SO GEOSTANDARDS NEWSLETTER LA English DT Article ID LANTHANIDE ORTHO-PHOSPHATES AB Fourteen rare-earth (plus scandium and yttrium) orthophosphates have been synthesized and characterized for use as electron microprobe reference samples. These reference samples are single-element phosphates that are homogeneous, stable under the electron beam, and free of interfering elements. They have a stoichiometric composition (RPO4) with the element of interest (R) ranging from 32 to 64 weight percent. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP JAROSEWICH, E (reprint author), NATL MUSEUM NAT HIST,DEPT MINERAL SCI,WASHINGTON,DC 20560, USA. NR 12 TC 152 Z9 154 U1 1 U2 4 PU GEOSTANDARDS PI VANDOEUVRE NANCY PA 15 RUE NOTRE-DAME-DES-PAUVRES BP 20, 54501 VANDOEUVRE NANCY, FRANCE SN 0150-5505 J9 GEOSTANDARD NEWSLETT JI Geostand. Newsl. PD OCT PY 1991 VL 15 IS 2 BP 397 EP 399 DI 10.1111/j.1751-908X.1991.tb00115.x PG 3 WC Geosciences, Multidisciplinary SC Geology GA GP288 UT WOS:A1991GP28800006 ER PT J AU WARREN, BF CLAPP, NK AF WARREN, BF CLAPP, NK TI SPECTRUM OF LIVER-DISEASE IN COTTON TOP TAMARIN COLITIS SO GUT LA English DT Meeting Abstract C1 UNIV BRISTOL,DEPT PATHOL,BRISTOL BS8 1TH,AVON,ENGLAND. OAK RIDGE ASSOCIATED UNIV,MARCOR,OAK RIDGE,TN 37830. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BRITISH MED JOURNAL PUBL GROUP PI LONDON PA BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON, ENGLAND WC1H 9JR SN 0017-5749 J9 GUT JI Gut PD OCT PY 1991 VL 32 IS 10 BP A1258 EP A1258 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA GK294 UT WOS:A1991GK29400334 ER PT J AU MARTZ, DE LANGNER, GH JOHNSON, PR AF MARTZ, DE LANGNER, GH JOHNSON, PR TI HALF-LIVES OF 214PB AND BI-214 SO HEALTH PHYSICS LA English DT Article ID DAUGHTERS; RADON; AIR AB New measurements on chemically separated samples of Bi-214 have yielded a mean half-life value of 19.71 +/- 0.02 min, where the error quoted is twice the standard deviation of the mean based on 23 decay runs. This result provides strong support for the historic 19.72 +/- 0.04 min half-life value and essentially excludes the 19.9-min value, both reported in previous studies. New measurements of the decay rate of Rn-222 progeny activity initially in radioactive equilibrium have yielded a value of 26.89 +/- 0.03 min for the half-life of 214Pb, where the error quoted is twice the standard deviation of the mean based on 12 decay runs. This value is 0.1 min longer than the currently accepted 214Pb half-value of 26.8 min. C1 VANDERBILT UNIV, DEPT ENVIRONM & WATER RESOURCES ENGN, NASHVILLE, TN 37420 USA. RP MARTZ, DE (reprint author), CHEM NUCL GEOTECH INC, US DOE, GRAND JUNCT PROJECTS OFF, POB 14000, GRAND JUNCTION, CO 81502 USA. NR 18 TC 2 Z9 2 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1991 VL 61 IS 4 BP 511 EP 518 DI 10.1097/00004032-199110000-00006 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GH834 UT WOS:A1991GH83400006 PM 1917488 ER PT J AU KOCHER, DC AF KOCHER, DC TI PERSPECTIVE ON THE HISTORICAL DEVELOPMENT OF RADIATION STANDARDS SO HEALTH PHYSICS LA English DT Article AB This paper discusses the historical development of standards for limiting routine radiation exposures of workers and the public. The radiobiological and epidemiological basis for radiation protection standards and practices, as this basis has evolved over time, is emphasized. Difficulties with using dose equivalents and nominal risk factors, which were developed primarily for purposes of radiation protection (i.e., to establish dose limits), in estimating radiation risks at the low levels of exposure routinely experienced in the workplace and the environment are discussed. The increasing importance of the principle that exposures should be reduced as low as reasonably achievable (ALARA) in radiation protection of workers and the public is described. RP KOCHER, DC (reprint author), OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, POB 2008, OAK RIDGE, TN 37830 USA. NR 40 TC 13 Z9 13 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1991 VL 61 IS 4 BP 519 EP 527 DI 10.1097/00004032-199110000-00007 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GH834 UT WOS:A1991GH83400007 PM 1917489 ER PT J AU ROBERSON, PL EICHNER, FN AF ROBERSON, PL EICHNER, FN TI USE OF THIN THERMOLUMINESCENT DOSIMETERS FOR PHANTOM SURFACE-DOSE MEASUREMENTS SO HEALTH PHYSICS LA English DT Note ID EXPOSURE C1 PACIFIC NW LAB, DEPT HLTH PHYS, RICHLAND, WA 99352 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1991 VL 61 IS 4 BP 529 EP 533 DI 10.1097/00004032-199110000-00008 PG 5 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GH834 UT WOS:A1991GH83400008 PM 1917490 ER PT J AU COURTNEY, JC CARNES, MD DWIGHT, CC FORRESTER, RJ AF COURTNEY, JC CARNES, MD DWIGHT, CC FORRESTER, RJ TI A DESCRIPTION OF THE DEMONSTRATION INTEGRAL FAST-REACTOR FUEL-CYCLE FACILITY SO HEALTH PHYSICS LA English DT Article AB A fuel examination facility at the Idaho National Engineering Laboratory is being converted into a facility that will electrochemically process spent fuel. This is an important step in the demonstration of the Integral Fast Reactor concept being developed by Argonne National Laboratory. Renovations are designed to bring the facility up to current health and safety and environmental standards and to support its new mission. Improvements include the addition of high-reliability earthquake hardened off-gas and electrical power systems, the upgrading of radiological instrumentation, and the incorporation of advances in contamination control. A major task is the construction of a new equipment repair and decontamination facility in the basement of the building to support operations. C1 ARGONNE NATL LAB, IDAHO FALLS, ID 83403 USA. RP COURTNEY, JC (reprint author), LOUISIANA STATE UNIV, CTR NUCL SCI, BATON ROUGE, LA 70803 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1991 VL 61 IS 4 BP 553 EP 563 DI 10.1097/00004032-199110000-00013 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GH834 UT WOS:A1991GH83400013 PM 1917494 ER PT J AU COURTNEY, JC DWIGHT, CC AF COURTNEY, JC DWIGHT, CC TI RADIATION SHIELDING DESIGN FOR A HOT REPAIR FACILITY SO HEALTH PHYSICS LA English DT Article AB A new repair and decontamination area is being built to support operations at the demonstration fuel cycle facility for the Integral Fast Reactor program at Argonne National Laboratory's site at the Idaho National Engineering Laboratory. Provisions are made for remote, glove wall, and contact maintenance on equipment removed from hot cells where spent fuel will be electrochemically processed and recycled to the Experimental Breeder Reactor-II. The source for the shielding design is contamination from a mix of fission and activation products present on items removed from the hot cells. The repair facility also serves as a transfer path for radioactive waste produced by processing operations. Radiation shields are designed to limit dose rates to no more than 5-mu-Sv h-1 (0.5 mrem h-1) in normally occupied areas. Point kernel calculations with buildup factors have been used to design the shielding and to position radiation monitors within the area. C1 ARGONNE NATL LAB, DIV FUEL CYCLE, IDAHO FALLS, ID 83403 USA. RP COURTNEY, JC (reprint author), LOUISIANA STATE UNIV, CTR NUCL SCI, BATON ROUGE, LA 70803 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1991 VL 61 IS 4 BP 565 EP 573 DI 10.1097/00004032-199110000-00014 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GH834 UT WOS:A1991GH83400014 PM 1917495 ER PT J AU SUN, JJ FRITZ, JS AF SUN, JJ FRITZ, JS TI ABSTRACTION OF BASIC COMPOUNDS BY SULFONATED POLYMERIC RESINS IN CAPILLARY GAS-CHROMATOGRAPHY SO HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY LA English DT Article DE CAPILLARY GC; SELECTIVITY; COMPOUND GROUP SEPARATION; CLEANUP; ADSORPTION OF BASIC COMPOUNDS; SULFONATED RESIN; QUANTITATION AB A small amount of a lightly sulfonated non-porous resin placed in the liner of the injection splitter of a gas chromatograph retains basic organic compounds but allows neutral compounds to be chromatographed normally. The organic bases in the gaseous state react with sulfonic acid groups on the resin surface to form protonated ions. Abstraction of bases is complete at a base:neutral molar ratio as high as 200:1 and a large number of samples can be injected before the sulfonated resins need to be replaced. RP SUN, JJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,DEPT CHEM,AMES,IA 50011, USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU DR ALFRED HUTHIG VERLAG GMBH PI HEIDELBERG 1 PA POSTFACH 102869, W-69018 HEIDELBERG 1, GERMANY SN 0935-6304 J9 HRC-J HIGH RES CHROM JI HRC-J. High Resolut. Chromatogr. PD OCT PY 1991 VL 14 IS 10 BP 656 EP 660 PG 5 WC Chemistry, Analytical SC Chemistry GA HH357 UT WOS:A1991HH35700003 ER PT J AU CHOW, WW CRAIG, RR AF CHOW, WW CRAIG, RR TI POWER SCALING IN QUANTUM-WELL LASER-AMPLIFIERS SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID SPONTANEOUS EMISSION; DIODE-LASERS; GAIN AB We investigated the effects of increasing excitation on the performance of quantum-well semiconductor laser amplifiers. Amplified spontaneous emission (ASE) and gain roll over at high injected carrier densities are two limitations to the power scaling of these devices. A Rigrod analysis is used to study the effects of these limitations on the gain, ratio of signal to ASE power, and efficiency for different values of injection current, facet reflectivity, and input laser intensity. Comparisons are made with an equivalent amplifier operating with a bulk semiconductor gain medium. Our analysis suggests that quantum-well semiconductor amplifier performance improves with a double-pass configuration. C1 SPECTRA DIODE LABS INC,SAN JOSE,CA 95134. RP CHOW, WW (reprint author), SANDIA NATL LABS,DIV 2535,ALBUQUERQUE,NM 87185, USA. NR 20 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 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD OCT PY 1991 VL 27 IS 10 BP 2267 EP 2273 DI 10.1109/3.97270 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA GM521 UT WOS:A1991GM52100005 ER PT J AU RANSIJN, H OCONNOR, P AF RANSIJN, H OCONNOR, P TI A PLL-BASED 2.5-GB/S GAAS CLOCK AND DATA REGENERATOR-IC SO IEEE JOURNAL OF SOLID-STATE CIRCUITS LA English DT Article; Proceedings Paper CT 1990 GAAS INTEGRATED CIRCUIT SYMP CY OCT 07-10, 1990 CL NEW ORLEANS, LA ID RECOVERY; CIRCUIT AB A GaAs IC that performs clock recovery and data retiming functions in 2.5-Gb/s fiber-optic communication systems is presented. Rather than using surface acoustic wave (SAW) filter technology, the IC employs a frequency- and phase-lock loop (FPLL) to recover a stable clock from pseudorandom NRZ data. The IC is mounted on a 1-in x 1-in ceramic substrate along with a companion Si bipolar chip that contains a loop filter and acquisition circuitry. At the SONET OC-48 rate of 2.488 Gb/s, the circuit meets requirements for jitter tolerance, jitter transfer, and jitter generation. The data input ambiguity is 25 mV while the recovered clock has less than 2-degrees rms edge jitter. The circuit functions up to 4 Gb/s with a 40-mV input ambiguity and 2-degrees rms clock jitter. Total current consumption from a single 5.2-V supply is 250 mA. C1 BROOKHAVEN NATL LAB,DIV INSTRUMENTAT,UPTON,NY 11973. RP RANSIJN, H (reprint author), AT&T BELL LABS,TECH STAFF,READING,PA 19609, USA. NR 24 TC 24 Z9 24 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9200 J9 IEEE J SOLID-ST CIRC JI IEEE J. Solid-State Circuit PD OCT PY 1991 VL 26 IS 10 BP 1345 EP 1353 DI 10.1109/4.90084 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA GG169 UT WOS:A1991GG16900003 ER PT J AU CHEO, BR JACHIM, SP AF CHEO, BR JACHIM, SP TI DYNAMIC INTERACTIONS BETWEEN RF SOURCES AND LINAC CAVITIES WITH BEAM LOADING SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article AB The issues of space-based, high-average-power, high-energy linear accelerators are addressed in connection with the associated RF power interaction problems. The basic operating principles of three types of LINAC's are reviewed. Models of the RF source/accelerator cavity interaction, including beam loading, are presented. This modeling also includes the effects of multiple-drive ports and spurious cavity modes. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP CHEO, BR (reprint author), POLYTECH INST NEW YORK,WEBER RES INST,FARMINGDALE,NY 11735, USA. NR 23 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD OCT PY 1991 VL 38 IS 10 BP 2264 EP 2274 DI 10.1109/16.88508 PG 11 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA GG470 UT WOS:A1991GG47000011 ER PT J AU HUNT, CE TRUJILLO, JT ORVIS, WJ AF HUNT, CE TRUJILLO, JT ORVIS, WJ TI STRUCTURE AND ELECTRICAL CHARACTERISTICS OF SILICON FIELD-EMISSION MICROELECTRONIC DEVICES SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article AB Field emission current is measured from arrays of wet chemically etched silicon cold-cathode diodes. Two types of cathode tips are measured both as-etched and after sharpening by low-temperature oxidation. The measurements are compared with results from simulations. The field enhancement increase resulting from tip sharpening is less than expected from simulation. The currents measured follow a Fowler-Nordheim characteristic and have been found temperature-insensitive from 130 to 360 K. Turn-on voltage is near 4 V, a value much less than measured from most other field emission sources. With a 920 nm anode-cathode spacing, a minimum 0.2-mu-A current per cathode is found. Telegraph noise of about 1% at 20 V is observed. These sharpened silicon tips are a viable cold cathode for vacuum microelectronics and other electron device applications. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ENGN RES,LIVERMORE,CA 94550. RP HUNT, CE (reprint author), UNIV CALIF DAVIS,DEPT ELECT ENGN & COMP SCI,DAVIS,CA 95616, USA. NR 9 TC 38 Z9 41 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 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD OCT PY 1991 VL 38 IS 10 BP 2309 EP 2313 DI 10.1109/16.88515 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA GG470 UT WOS:A1991GG47000018 ER PT J AU BROSS, AD PLADALMAU, A BAUMBAUGH, B GODFREY, J JAQUES, J MARCHANT, J PIEKARZ, J RUCHTI, R AF BROSS, AD PLADALMAU, A BAUMBAUGH, B GODFREY, J JAQUES, J MARCHANT, J PIEKARZ, J RUCHTI, R TI NEW SCINTILLATION MATERIALS FOR FIBER TRACKING AND CALORIMETRY SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article AB Radiation damage studies were performed on new polystyrene-based plastic scintillators. Several samples of different multicomponent systems containing new fluorescent compounds were irradiated with a Co-60 source to a 10 Mrad dose. After irradiation, the samples were annealed for ten days in oxygen and three days in air. Scintillation light output, fluorescence, and transmittance spectra were recorded at three different stages: before irradiation, immediately after irradiation, and after the annealing process. After irradiation and the annealing period, the light output of the best scintillators had decreased by 10% of their original values. C1 UNIV NOTRE DAME,NOTRE DAME,IN 46556. RP BROSS, AD (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD OCT PY 1991 VL 38 IS 5 BP 994 EP 998 DI 10.1109/23.108359 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GX349 UT WOS:A1991GX34900003 ER PT J AU HAN, BM KARADY, GG THIESSEN, HA AF HAN, BM KARADY, GG THIESSEN, HA TI TUNING MAGNET CURRENT-CONDITIONING SYSTEM FOR RF CAVITY IN A HIGH-INTENSITY PROTON ACCELERATOR SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article AB The development of a current-conditioning system for the tuning magnet of an RF cavity in a high-intensity proton accelerator is described. The conceived system has a bridge configuration consisting of a power amplifier, transistor switch, and power diodes. It works as a power amplifier during the acceleration period and recovers into the capacitor bank the inductive energy stored in the tuning magnet during the reset period. The system operation concept was verified by computer simulation, and the system design was based on the test results of a 1/100th scale model, which was built to evaluate the feasibility of hardware realization. The hardware system was built with commercially available components and tested in connection with a prototype RF cavity at the Los Alamos National Laboratory. This system can provide an accurate current waveform (low ripple), recover the inductive energy in the tuning magnet, and easily control the dc bias level. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP HAN, BM (reprint author), ARIZONA STATE UNIV,TEMPE,AZ 85287, USA. NR 8 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD OCT PY 1991 VL 38 IS 5 BP 1005 EP 1012 DI 10.1109/23.108361 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA GX349 UT WOS:A1991GX34900005 ER PT J AU SCHAMILOGLU, E STINNETT, RW AF SCHAMILOGLU, E STINNETT, RW TI VACUUM DISCHARGE PLASMAS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Editorial Material C1 SANDIA NATL LABS,DIV 1264,ALBUQUERQUE,NM 87185. RP SCHAMILOGLU, E (reprint author), UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,ALBUQUERQUE,NM 87131, 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 681 EP 681 PG 1 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600001 ER PT J AU KADISH, A MAIER, WB ROBISCOE, RT AF KADISH, A MAIER, WB ROBISCOE, RT TI MACROSCOPIC MODELS OF INTERNAL DYNAMICS OF ELECTRICAL DISCHARGES SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID LUMPED-CIRCUIT MODEL; DIELECTRIC SURFACES; ARC RESISTANCE AB The existence of thresholds for electrical discharge onset suggests a functional relation between macroscopic resistivity and current. At low current, the resistivity should be inversely proportional to the magnitude of the current. Macroscopic models which employ this scaling predict many empirically observed properties of transient electrical discharges such as: (i) thresholds for the onset of current, (ii) the abrupt termination of current in active regions of a current channel, (iii) current restart in passive regions of current channels' (iv) leaders, and (v) residual charge, both in channels and at sources when current terminates. We present an overview of research with these models and use examples to illustrate the results that have been obtained. We also show how these models predict current channel formation and describe results of efforts to benchmark theory with experimental data. C1 MONTANA STATE UNIV,BOZEMAN,MT 59717. RP KADISH, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 12 TC 7 Z9 7 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 697 EP 704 DI 10.1109/27.108401 PG 8 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600004 ER PT J AU BROWN, IG GODECHOT, X AF BROWN, IG GODECHOT, X TI VACUUM-ARC ION CHARGE-STATE DISTRIBUTIONS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB We have measured vacuum arc ion charge-state spectra for a wide range of metallic cathode materials. The charge-state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. We have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th, and U. The arc was operated in a pulsed mode with pulse length 0.25 ms; arc current was 100 A throughout. This array of elements extends and completes previous work by the authors. In this paper the measured distributions are cataloged and compared with their earlier results and those of other workers. We also make some observations about the performance of the various elements as suitable vacuum arc cathode materials. RP BROWN, IG (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV ACCELERATOR & FUS RES, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 18 TC 152 Z9 158 U1 1 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 EI 1939-9375 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 713 EP 717 DI 10.1109/27.108403 PG 5 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600006 ER PT J AU RUTKOWSKI, HL HEWETT, DW HUMPHRIES, S AF RUTKOWSKI, HL HEWETT, DW HUMPHRIES, S TI DEVELOPMENT OF ARC ION SOURCES FOR HEAVY-ION FUSION SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID MULTIPLY CHARGED IONS AB Heavy ion fusion (HIF) places great demands on the capabilities of ion sources. There are two approaches to HIF-the RF linac-storage ring approach, and the induction linac approach. The first option is pursued mainly in Europe, where the main centers of source work are GSI in Darmstadt, Germany, and the Institute of Theoretical and Experimental Physics in Moscow. RF linac schemes require low emittance and moderate current levels, because the beam is accumulated in storage rings before being focused on target. The induction linac approach being pursued at the Lawrence Berkeley Laboratory (LBL) requires low emittance and high current, because this is a single pass approach to HIF and one wishes to limit the number of beams in the machine. The RF scheme generally uses long pulse sources together with a buncher or RFQ. The induction linac approach requires sources in the microsecond pulse length range, with good optics being maintained during the pulse. The mainline source being pursued at LBL is a carbon vacuum arc providing 500 mA of ions per beam, which incorporates electrostatic confinement of the plasma to provide a stable ion-extraction surface geometry throughout the pulse duration (plasma switch). Other materials can be used for the arc cathode to provide heavier ions, and indeed some work has been performed with aluminum. At the present stage of the program, the emphasis is on scaled accelerator experiments which require lighter ions. The electrostatic fields used for the plasma confinement have great effect on the output emittance of the source, and particle-in-cell simulations have been performed to find an optimum solution for a given set of plasma parameters that will result in a minimum source emittance. The present design goal for the LBL source which will be used in the 16 beam 2 MV injector is 5 x 10(-7)pi-m-rad normalized. Without plasma switch optimization, the achieved normalized emittance is 2.0-2.5 x 10(-6)pi-m-rad. Experiments have also been performed to show the enhanced yield of multiple charge state ions, which have considerable impact on the cost of any heavy ion driver for fusion. This enhanced yield is accomplished by modifying the plasma potential in the source. Langmuir probe diagnosis of the plasma has been performed as part of the effort to reduce emittance by tailoring the output plasma to the conditions suggested by the simulations. Considerable effort has also been devoted to lifetime enhancement and remote trigger cleaning methods. The normal lifetime of the source is 20-30 K shots, which is fine for an experimental machine but clearly not suitable for a commercial driver. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,ALBUQUERQUE,NM 87131. RP RUTKOWSKI, HL (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,HEAVY ION FUS ACCELERATOR RES GRP,BERKELEY,CA 94720, USA. NR 11 TC 7 Z9 7 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 782 EP 789 DI 10.1109/27.108415 PG 8 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600018 ER PT J AU CUNEO, ME LOCKNER, TR TISONE, GC AF CUNEO, ME LOCKNER, TR TISONE, GC TI A REFRACTIVE-INDEX GRADIENT (RING) DIAGNOSTIC FOR TRANSIENT DISCHARGES OR EXPANSIONS OF VAPOR OR PLASMAS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID DEFLECTION TECHNIQUE; DENSITY; LITHIUM; MEDIA; GAS AB The Refractive INdex Gradient (RING) diagnostic described in this paper uses a fast, silicon, photodiode quadrant detector with a differential amplifier to temporally detect the refraction of a CW laser by transient discharges or expansions of vapor, gas, or plasma. The method is a local, one-dimensional, time-resolved, quantitative, species-discriminating (i.e., atoms or electrons) Schlieren technique. The diagnostic is easy to field, sensitive (minimum deflection angles detectable almost-equal-to 0.3-mu-rad), and fast (risetime = 11 +/- 1 ns). Circuit design, performance, and diagnostic theory will be discussed. The RING diagnostic bas been applied to measurements on several ion sources under development at Sandia National Laboratory for use on intense applied-B ion diodes in the light ion-beam fusion program. Sources studied include different types of flashboards, a thermal evaporation lithium ion source, and a laser-produced ion source. Measurements have been made both in labs and directly on large pulsed power accelerators. To illustrate the utility of this technique, examples of measurements on LEVIS (Laser EVaporation Ion Source), a laser-produced, active, lithium ion source will be given. Measured properties include vapor/plasma production thresholds, expansion velocities, and time-resolved gradient and density spatial profiles. Comparisons of the RING results with measurements using a Faraday cup and a double-floating Langmuir probe will be presented. RP CUNEO, ME (reprint author), SANDIA NATL LABS,PULSED POWER SCI DIRECTORATE,ALBUQUERQUE,NM 87185, USA. NR 38 TC 7 Z9 7 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 800 EP 813 DI 10.1109/27.108417 PG 14 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600020 ER PT J AU ROSENTHAL, SE AF ROSENTHAL, SE TI CHARACTERIZATION OF ELECTRON FLOW IN NEGATIVE-POLARITY AND POSITIVE-POLARITY LINEAR-INDUCTION ACCELERATORS SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID TRANSMISSION-LINES; IMPEDANCE AB Experiments at the Sandia National Laboratories have studied the operation of the linear-induction accelerators, HELIA [1] and Hermes III [2], in both negative and positive polarities. The experiments in positive polarity have provided a unique opportunity to explore the consequences of multiple-cathode electron emission in magnetically insulated transmission lines. An examination of the total energy-canonical momentum distribution of the electrons explains the features of the magnetically insulated flow exhibited by these systems. Simple analysis based on the basic concept of pressure balance, in conjunction with particle-in-cell numerical simulations, shows how the line voltage is related to the anode and cathode currents. Two flow designations are introduced that can apply to multiple-cathode, magnetically insulated transmission lines: full-gap flow (FGF), and locally emitted flow (LEF). RP ROSENTHAL, SE (reprint author), SANDIA NATL LABS,DIV PULSED POWER THEORY,ALBUQUERQUE,NM 87185, USA. NR 25 TC 22 Z9 22 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 822 EP 830 DI 10.1109/27.108419 PG 9 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600022 ER PT J AU HANSON, DL CUNEO, ME MCKAY, PF COATS, RS ROSENTHAL, SE AF HANSON, DL CUNEO, ME MCKAY, PF COATS, RS ROSENTHAL, SE TI ION COUPLING EFFICIENCY FOR AN EXTRACTION APPLIED-B ION DIODE ON THE HELIA LINEAR-INDUCTION ADDER IN POSITIVE POLARITY SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID ELECTRON AB We report on initial experiments to investigate coupling of the four-stage HELIA linear-induction accelerator (3.6 MV, 180 kA, 30 ns FWHM) to a uniformly insulated applied-B ion diode in planar extraction geometry. Extraction of an annular ion beam parallel to the diode axis for ion transport and focusing experiments requires that HELIA operate in positive (reverse) polarity, where each of the four cathode voltage adder sections contributes a group of electrons of unique energy and canonical angular momentum to electron flow in a magnetically insulated transmission line (MITL). We show that a number of requirements must be met for the efficient production of a uniform high intensity ion beam. An appropriate insulating magnetic field geometry is needed to provide uniform insulation of the anode ion-emitting surface and reduce direct electron losses from the cathode MITL region to the anode. A flat diode impedance profile with Z(D) < Z(SELF-LIMITED) is required for efficient MITL power coupling to the diode. Even when the MITL is efficiently insulated upstream of the diode, we observe that some flow (MITL sheath) electrons are lost directly to the anode along flux lines of the diode-insulating magnetic field. These losses (amounting to about 10-20% of the total current) slightly reduce overall ion coupling efficiency compared to ion diodes with a more conventional MITL power flow, but may also aid in the very rapid turn-on (< 6 ns) of dielectric flashover ion sources on this diode. In these experiments, we achieved ion coupling efficiencies I(ION)/I(TOT) of 60-70% at peak ion power and ion generation efficiencies I(ION)/I(DIODE) of 80-90% at peak ion power under optimum conditions. These ion efficiencies, if maintained on higher power extraction diodes, would be adequate for ICF (Inertial Confinement Fusion) applications, including a light ion-driver module for the proposed Laboratory Microfusion Facility. RP HANSON, DL (reprint author), SANDIA NATL LABS,DIV PULSED POWER THEORY,ALBUQUERQUE,NM 87185, USA. NR 13 TC 7 Z9 7 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 831 EP 839 DI 10.1109/27.108420 PG 9 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600023 ER PT J AU MANSFIELD, CR OONA, H SHURTER, RP AF MANSFIELD, CR OONA, H SHURTER, RP TI BEAM ROTATION AND SHEAR IN A LARGE ELECTRON-BEAM DIODE SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY AB The time-averaged electron-beam current distribution of one of the electron guns of the Large Aperture Module (LAM) of the Aurora laser was measured as part of a larger set of experiments designed to study the electron beam transport to and energy deposition in the LAM laser chamber. A 16-gauge stainless steel sheet was placed inside the laser chamber and served multiple purposes. First, it was used to convert high-energy electrons into X-rays in order to make radiograms of the electron beam. Second, the sheet was used as a Faraday cup to measure the total beam current. Third, individual Faraday cups were mounted on the plate to sample the time history of the electron beam at various positions. The radiograms made on the center line of the LAM laser chamber while the laser chamber was at vacuum (10-50-mu-m pressure) demonstrated several of the expected results. The beam was relatively uniform over the aperture, with the exception of shadows cast by the diode anode wires, the Hibachi ribs, and the Hibachi support structure. At a depth of 50 cm into the laser chamber, the self-magnetic field of the beam produced a shear in the top and bottom edges of 15 cm. At the same depth the applied magnetic field caused a rotation of the entire beam profile of about 3-degrees. RP MANSFIELD, CR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,PULSED POWER SYST,CLS-7,MS E525,POB 1663,LOS ALAMOS,NM 87545, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 840 EP 845 DI 10.1109/27.108421 PG 6 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600024 ER PT J AU SHURTER, R COOGAN, J JONES, M OONA, H ROSE, E SADLER, C THOMAS, V AF SHURTER, R COOGAN, J JONES, M OONA, H ROSE, E SADLER, C THOMAS, V TI PERFORMANCE IMPROVEMENTS WITH ADVANCED DESIGN FOILS IN HIGH-CURRENT ELECTRON-BEAM DIODES SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY ID KRF AB A novel design for the vacuum/pressure barrier of an electron-beam diode is ready to be fielded on a large krypton-fluoride excimer laser. The new barrier is a composite foil, fabricated from carbon fibers, Kapton-membrane, epoxy, and copper foil. This composite foil has advantages over more traditional metal foils, exhibiting particularly high tensile strength and a high modulus of elasticity. Other important properties of these composites for use in KrF excimer laser applications include: high electron transmission with low loss to scattering, chemical compatibility with fluorine, low porosity, and low reflectivity in the ultraviolet. The mechanical properties of the composite foil allow the design of support structures (hibachis) which incorporate larger openings than are possible with metal foils with similar electron transmission characteristics. This ability to span larger openings in the foil support structure will allow a reduction in the blocked fraction of the electron beam and promote enhanced energy delivery to the laser gas. Experiments to qualify the composite foils are underway on a diode with a 200 cm2 cathode. The composite foils will be fielded on the Aurora Intermediate Amplifier with a 280 x 40-cm cathode, producing a 20-A/cm2, 525-kV, 600-ns electron beam. The composite foil, mounted on a hibachi with 21.8 x 41.3-cm openings, will replace a 2-mil titanium foil mounted on a hibachi with 5.8 x 11.25-cm openings. Experimental results will be presented, as will the predictions from the ISIS 3-D electron-beam transport code. RP SHURTER, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,POB 1663,LOS ALAMOS,NM 87544, USA. NR 5 TC 1 Z9 1 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 846 EP 849 DI 10.1109/27.108422 PG 4 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600025 ER PT J AU SMITH, JR SHOKAIR, IR STRUVE, KW SCHAMILOGLU, E WERNER, PW LIPINSKI, RJ AF SMITH, JR SHOKAIR, IR STRUVE, KW SCHAMILOGLU, E WERNER, PW LIPINSKI, RJ TI TRANSVERSE OSCILLATIONS OF A LONG-PULSE ELECTRON-BEAM ON A LASER-FORMED CHANNEL SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT 14TH INTERNATIONAL SYMP ON DISCHARGES AND ELECTRICAL INSULATION IN VACUUM ( ISDEIV ) CY SEP 17-20, 1990 CL SANTA FE, NM SP SANDIA NATL LABS, LOS ALAMOS NATL LAB, UNIV NEW MEXICO, TEXAS TECH UNIV, MAXWELL LABS, PHYS INT, TITAN CORP, PULSE SCI DIV, USN, NAVAL RES LAB, PLASMA PHYS DIV, USN, NAVAL SURFACE WARFARE CTR, US DEPT DEF, DEF NUCL AGCY AB An intense relativistic electron beam may be transported in low-pressure gas using an ion channel which focuses and guides the beam. The beam can be unstable to the growth of transverse oscillations caused by the electric force between the beam and channel-the ion hose instability. In this report we address beam propagation on channels created by photoionization of gas with an excimer laser. Ion hose oscillations have been recorded which have a betatron wavelength of approximately 1.5 m. The growth rate of the ion hose instability in the linear regime was measured as 1.67 +/- 0.45. At this level of growth, the amplitude of beam oscillations equals the channel radius after a period of one-third of an ion oscillation time. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. MISSION RES CORP,ALBUQUERQUE,NM 87108. UNIV NEW MEXICO,DEPT MED SOCIALE & PREVENT,ALBUQUERQUE,NM 87131. RP SMITH, JR (reprint author), TITAN,DIV SPECTRON,ALBUQUERQUE,NM 87119, USA. NR 9 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 850 EP 854 DI 10.1109/27.108423 PG 5 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600026 ER PT J AU PREGENZER, AL AF PREGENZER, AL TI HIGH-FREQUENCY PARAMETRIC-EXCITATION OF ELECTROHYDRODYNAMIC INSTABILITIES - APPLICATIONS TO LARGE-AREA ION SOURCES SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Note AB Recent experimental and theoretical work has shown that high-frequency microwave sources can excite electrohydrodynamic instabilities on liquid metal surfaces through parametric resonance. Here, we show that parametric resonance may be useful in two-dimensional ion source experiments by reducing the value of the electric field required to produce instabilities leading to ion emission. C1 SANDIA NATL LABS,DIV 9241,ALBUQUERQUE,NM 87185. NR 7 TC 1 Z9 1 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1991 VL 19 IS 5 BP 860 EP 861 DI 10.1109/27.108425 PG 2 WC Physics, Fluids & Plasmas SC Physics GA GT576 UT WOS:A1991GT57600028 ER PT J AU MASOUM, MAS FUCHS, EF ROESLER, DJ AF MASOUM, MAS FUCHS, EF ROESLER, DJ TI LARGE-SIGNAL NONLINEAR MODEL OF ANISOTROPIC TRANSFORMERS FOR NONSINUSOIDAL OPERATION .2. MAGNETIZING AND CORE-LOSS CURRENTS SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE NONLINEAR ANISOTROPIC TRANSFORMERS; NONSINUSOIDAL OPERATION; POWER QUALITY AB No-load currents and voltages of saturated single-phase transformers are computed based on given lambda-i and harmonic core-loss characteristics. First, the induced voltage and instantaneous magnetizing current are calculated for given sinusoidal or nonsinusoidal terminal voltages. Subsequently, the harmonic components of the magnetizing current are obtained from a Fourier analysis and the associated flux linkage time function can be determined and used to compute the flux density components within each mesh of the transformer core grid structure. These harmonic flux density amplitudes can then be employed to calculate the harmonic core losses based on measured harmonic iron-core loss and newly defined phase-factor functions. The core losses are then used to calculate the harmonic components of the core-loss current. The no-load current is obtained from the sum of the magnetizing and the core-loss current components. The calculated sinusoidal or nonsinusoidal no-load current will be expanded into its harmonic components; thus, taking skin effects into account, the ohmic losses caused by all harmonics of the no-load current can be calculated. Finally, the waveform of the no-load current and the calculated losses are compared with measurements for various voltage waveshapes. C1 US DOE,WASHINGTON,DC 20585. RP MASOUM, MAS (reprint author), UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309, USA. NR 5 TC 15 Z9 15 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD OCT PY 1991 VL 6 IS 4 BP 1509 EP 1516 DI 10.1109/61.97686 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA GK858 UT WOS:A1991GK85800024 ER PT J AU SMOLLECK, HA RANADE, SJ PRASAD, NR VELASCO, RO AF SMOLLECK, HA RANADE, SJ PRASAD, NR VELASCO, RO TI EFFECTS OF PULSED-POWER LOADS UPON AN ELECTRIC-POWER GRID SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE PULSE POWER; PULSED LOADS; FLICKER; STABILITY; TRANSIENTS AB Certain proposed particle-accelerator and laser experiments, and other devices related to fusion research, require multi-megawatt, repetitive power pulses, often at low (subsynchronous) frequency. While some power-delivery technologies call for a certain degree of buffering of the utility demand using capacitive, inductive, or inertial energy storage, considerations have also been made for serving such loads directly from the line. In either case, such pulsed loads represent non-traditional applications from the utility's perspective which, in certain cases, can have significant design and operational implications. This paper outlines an approach to the analysis of the effects of such loads upon the electric power grid using existing analysis techniques. The impacts studied include bus-voltage flicker, transient and dynamic stability, and torsional excitation. The impact of a particular pulsed load is examined and illustrated for the power network serving the Los Alamos National Laboratory. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP SMOLLECK, HA (reprint author), NEW MEXICO STATE UNIV,DEPT ELECT & COMP ENGN,LAS CRUCES,NM 88003, USA. NR 19 TC 6 Z9 7 U1 2 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD OCT PY 1991 VL 6 IS 4 BP 1629 EP 1640 DI 10.1109/61.97702 PG 12 WC Engineering, Electrical & Electronic SC Engineering GA GK858 UT WOS:A1991GK85800040 ER PT J AU MASOUM, MAS FUCHS, EF ROESLER, DJ AF MASOUM, MAS FUCHS, EF ROESLER, DJ TI IMPACT OF NONLINEAR LOADS ON ANISOTROPIC TRANSFORMERS SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE NONLINEAR LOADS OF ANISOTROPIC TRANSFORMERS; NONSINUSOIDAL OPERATION; POWER QUALITY AB The impact of nonlinear loads on anisotropic transformers is investigated. The saturation of the iron-core materials, the anisotropy of the with- and cross-grain laminations, the dependency of the iron-core losses on the amplitudes of the fundamental and harmonics of the flux density and the dependency of the iron-core losses on the waveshape (harmonic phase shifts) of the flux density are included in this analysis. The impact of nonlinear loads on anisotropic transformers exhibits itself as an increase in losses (%) and consequently a decrease in the performance or derating of the transformer. The approach to obtain the increases in losses (%) requires the computation of the appropriate input voltage and the core-loss resistances assuming that the fundamental components of the output voltage and current have rated quantities and that the secondary current contains a certain amount of low-order harmonics, caused by the nonlinear loads. The determination of derating factors of transformers requires a three-step iterative method assuming rated fundamental output voltage and rated secondary apparent power while maintaining rated losses. C1 US DOE,WASHINGTON,DC 20585. RP MASOUM, MAS (reprint author), UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309, USA. NR 4 TC 12 Z9 13 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD OCT PY 1991 VL 6 IS 4 BP 1781 EP 1788 DI 10.1109/61.97721 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA GK858 UT WOS:A1991GK85800059 ER PT J AU DUBEY, RV EULER, JA BABCOCK, SM AF DUBEY, RV EULER, JA BABCOCK, SM TI REAL-TIME IMPLEMENTATION OF AN OPTIMIZATION SCHEME FOR 7-DEGREES-OF-FREEDOM REDUNDANT MANIPULATORS SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article AB A computationally efficient, kinematic optimal control scheme is presented for seven-degree-of-freedom (7-DOF) manipulators. This scheme uses the gradient projection optimization method in the framework of resolved motion rate control, and it does not require calculation of the pseudoinverse of the Jacobian. An efficient formulation for determining joint velocities for given Cartesian components of linear and angular end-effector velocities is obtained. Thus, this control scheme is well suited for real-time implementation, which is essential if the end-effector trajectory is continuously modified based on sensory feedback. Implementation of this scheme on a Motorola 68020 VME bus-based controller of the 7-DOF manipulator at the Center for Engineering Systems Advanced Research (CESAR) is described. A comparison of computational complexity with previously available schemes is presented. C1 OAK RIDGE NATL LAB,DIV ROBOT & PROC SYST,OAK RIDGE,TN 37831. RP DUBEY, RV (reprint author), UNIV TENNESSEE,DEPT MECH & AEROSP ENGN,KNOXVILLE,TN 37996, USA. NR 19 TC 32 Z9 41 U1 0 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD OCT PY 1991 VL 7 IS 5 BP 579 EP 588 DI 10.1109/70.97869 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA GH852 UT WOS:A1991GH85200002 ER PT J AU LITTLEJOHN, D CHANG, SG AF LITTLEJOHN, D CHANG, SG TI SOLUBILITY OF THE POTASSIUM-SALTS OF NITROGEN SULFUR-COMPOUNDS IN AQUEOUS-SOLUTION SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Note ID DENITRIFICATION SYSTEM; DESULFURIZATION AB The aqueous solubility of the potassium salts of hydroxyimidodisulfate (HADS), hydroxysulfamic acid (HAMS), nitridotrisulfate (ATS), and imidodisulfate (ADS) have been determined by Raman spectrometry and ion chromatography over a temperature range of 0-50-degrees-C. The compounds were synthesized and saturated solutions were prepared in a controlled-temperature bath. The solutions were diluted with either a reference solution, for Raman analysis, or with water, for ion chromatographic analysis. Equations for the solubilities were derived as a function of temperature. The effects of the solubilities of the nitrogen-sulfur compounds on the operation of wet flue gas scrubbing systems is discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720. NR 13 TC 1 Z9 1 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD OCT PY 1991 VL 30 IS 10 BP 2350 EP 2352 DI 10.1021/ie00058a016 PG 3 WC Engineering, Chemical SC Engineering GA GJ602 UT WOS:A1991GJ60200016 ER PT J AU ALDRIDGE, HK LIU, X LIN, MC MELIUS, CF AF ALDRIDGE, HK LIU, X LIN, MC MELIUS, CF TI THERMAL UNIMOLECULAR DECOMPOSITION OF 1,3,5-TRIOXANE - COMPARISON OF THEORY AND EXPERIMENT SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article AB The unimolecular decomposition of 1,3,5-trioxane into three formaldehyde molecules has been studied thermally at eight temperatures between 523 and 603 K using mixtures highly diluted with Ar. Under these conditions, the only decomposition product detected by means of FTIR analysis was formaldehyde. At 588 K, the effect of total pressure was examined between 25 and 800 torr; a noticeable decline in the first-order rate constant was observed only at pressures below 500 torr. A least-squares analysis of the measured high-pressure, first-order rate constants leads to k1 = 10(15.78 +/- 0.19) exp[(-25,620 +/- 254)/T]s-1. This result differs significantly from earlier data on the reaction, but it compares closely with the theoretical value: k1(BAC-MP4) = 10(15.67 +/- 0.01) exp[(-25,760 +/- 20)/T]s-1. computed with the transition-state theory using the molecular and TST parameters predicted by the BAC-MP4 method. C1 SANDIA NATL LABS,COMBUST RES FAC,LIVERMORE,CA 94550. RP ALDRIDGE, HK (reprint author), EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322, USA. NR 12 TC 19 Z9 19 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD OCT PY 1991 VL 23 IS 10 BP 947 EP 956 DI 10.1002/kin.550231009 PG 10 WC Chemistry, Physical SC Chemistry GA GF361 UT WOS:A1991GF36100008 ER PT J AU DUFFEY, RB HUGHES, ED AF DUFFEY, RB HUGHES, ED TI STATIC FLOW INSTABILITY ONSET IN TUBES, CHANNELS, ANNULI, AND ROD BUNDLES SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article AB A theoretical model is developed for the onset of flow instability for vertical upflow and downflow of a boiling fluid in a constant pressure drop flow channel. The model is based on momentum and energy balance equations with an algebraic modeling of two-phase velocity-slip effects. Predictions of the theory are tested against experimental data for pressure, heat flux, length, inlet subcooling, and exit fluid quality effects. The predictions of the dependency of the minimum mass flux on these variables are in complete agreement with the trends of the data. The experimental data have been taken from round tube, rectangular channel, annuli, and rod bundle geometries, with vertical upflow and downflow, under both non-bulk boiling and net vapor generation conditions. The data collection given here appears to be among the most complete available in the literature. The theoretical results suggest a method for correlating about limited ranges of operating state parameters for a fixed geometry. The method is given in the paper along with specific correlating lines. RP DUFFEY, RB (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,ENERGY & SYST TECHNOL,POB 1625,IDAHO FALLS,ID 83415, USA. NR 32 TC 16 Z9 16 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 1991 VL 34 IS 10 BP 2483 EP 2496 DI 10.1016/0017-9310(91)90090-2 PG 14 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA GH845 UT WOS:A1991GH84500005 ER PT J AU BOHN, MS SWANSON, LW AF BOHN, MS SWANSON, LW TI A COMPARISON OF MODELS AND EXPERIMENTAL-DATA FOR PRESSURE-DROP AND HEAT-TRANSFER IN IRRIGATED PACKED-BEDS SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID COLUMNS AB This paper presents a comparison of experimental data with models of heat exchange and pressure drop in irrigated packed beds with special emphasis on determining the validity of the models, the importance of radiation heat transfer, and the effectiveness of such heat exchangers. Heat transfer and pressure drop are measured in a 150 mm (i.d.) column with a 610 mm bed of metal Pall rings. Molten nitrate salt and preheated air are the working fluids. Salt inlet temperatures ranging from 335 to 520-degrees-C and air inlet temperatures ranging from 215 to 380-degrees-C are tested. A comparison between the experimental data and a modified version of the heat transfer model of Bohn (Proc. 2nd ASME-JSME Thermal Engng Conf., Honolulu, Hawaii (1987)) is made on the basis of heat transfer from the salt. For the range of air and salt rates tested, 0.3-1.4 kg m-2 s-1 air flow and 6-18 kg m-2 s-1 salt flow, the data agree with the model within 25% standard deviation. The role of radiation heat transfer is found to be relatively minor and the heat exchanger is found to behave essentially as a simple counterflow exchanger with a heat exchange effectiveness of unity. Two models for the column pressure drop are compared with the data over a pressure drop ranging from 160 to 1045 Pa m-1. The standard deviation for the model of Stichlmair et al. (Gas Separation Purification 3, 19-28 (1989)) is 9.4%; that for the model of Bemer and Kalis (Trans. Instn Chem. Engrs 56, 200-204 (1978)) is 16.4%. C1 UNIV DENVER,DEPT ENGN,DENVER,CO 80208. RP BOHN, MS (reprint author), SOLAR ENERGY RES INST,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 33 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 1991 VL 34 IS 10 BP 2509 EP 2519 DI 10.1016/0017-9310(91)90092-S PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA GH845 UT WOS:A1991GH84500007 ER PT J AU LAGE, JL BEJAN, A ANDERSON, R AF LAGE, JL BEJAN, A ANDERSON, R TI EFFICIENCY OF TRANSIENT CONTAMINANT REMOVAL FROM A SLOT VENTILATED ENCLOSURE SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID MODEL; TURBULENCE AB This paper reports the results of a fundamental study of the transient removal of a contaminant from a two-dimensional enclosure with one inlet and one outlet. The evolution of the flow and concentration fields are simulated numerically using Jones and Launder's low Reynolds number k-epsilon model. The Reynolds number is varied over the range 5-5000, where Re is based on the jet inlet width. The effectiveness of this forced convection mass transfer process is documented quantitatively in terms of a ventilation efficiency and a critical concentration decay time. The relationship between these quantitative performance parameters, the Reynolds number and the ventilation jet orientation, is reported. It is shown that significant gains in ventilation efficiency (or a shortening of the critical concentration decay time) can be made by properly orienting and positioning the inlet and outlet ports relative to each other and to the enclosure. The numerical ventilation efficiency results are summarized by a compact analytical expression based on a theoretical two-zone model of the enclosure flow. C1 SOLAR ENERGY RES INST,BLDG ENERGY TECHNOL PROGRAM,GOLDEN,CO 80401. RP LAGE, JL (reprint author), DUKE UNIV,DEPT MECH ENGN & MAT SCI,DURHAM,NC 27706, USA. RI Bejan, Adrian/D-3909-2012 NR 17 TC 26 Z9 26 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 1991 VL 34 IS 10 BP 2603 EP 2615 DI 10.1016/0017-9310(91)90100-S PG 13 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA GH845 UT WOS:A1991GH84500015 ER PT J AU RADFORD, HE EVENSON, KM MATUSHIMA, F ZINK, LR GALVAO, GP SEARS, TJ AF RADFORD, HE EVENSON, KM MATUSHIMA, F ZINK, LR GALVAO, GP SEARS, TJ TI FAR INFRARED-LASER FREQUENCIES OF CH3OD AND N2H4 SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE CH3OD; N2H4; MOLECULAR LASER LINES; LASER FREQUENCY MEASUREMENTS; OPTICALLY PUMPED FAR INFRARED LASERS AB The frequencies of 26 laser lines with wavelengths between 57 and 534-mu-m have been measured in the optically pumped laser gases CH3OD and N2H4. A pair of stabilized cw (CO2)-C-12 lasers was used as a frequency standard for the heterodyne frequency measurements. Seven of the 26 lines are new. C1 NATL INST STAND & TECHNOL,DIV TIME & FREQUENCY,BOULDER,CO 80303. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. TOYAMA UNIV,DEPT PHYS,TOYAMA 930,JAPAN. INST NACL PESQUISAS ESPACIAIS,BR-12201 SAO JOSE CAMPOS,SP,BRAZIL. RP RADFORD, HE (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,DIV ATOM & MOLEC PHYS,CAMBRIDGE,MA 02138, USA. RI Sears, Trevor/B-5990-2013 OI Sears, Trevor/0000-0002-5559-0154 NR 5 TC 14 Z9 14 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD OCT PY 1991 VL 12 IS 10 BP 1161 EP 1166 DI 10.1007/BF01008558 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA GJ575 UT WOS:A1991GJ57500005 ER PT J AU LEHNERT, BE DETHLOFF, LA FINKELSTEIN, JN VANDERKOGEL, AJ AF LEHNERT, BE DETHLOFF, LA FINKELSTEIN, JN VANDERKOGEL, AJ TI TEMPORAL SEQUENCE OF EARLY ALTERATIONS IN RAT LUNG FOLLOWING THORACIC X-IRRADIATION SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID PULMONARY SURFACTANT SYSTEM; MAST-CELL GRANULES; BRONCHOALVEOLAR LAVAGE; MOUSE LUNG; VASCULAR-PERMEABILITY; RADIATION PNEUMONITIS; IONIZING IRRADIATION; FIBROSIS; HISTAMINE; INJURY AB The temporal patterns of several responses in the lungs of groups of rats administered two different thoracic doses of X-rays (7.5 and 15 Gy) were examined during a time frame within which radiation pneumonitis develops (1-13-week period) in order to assess for potential interrelationships among the responses. Endpoints surveyed included lung gravimetric and volumetric changes, changes in lavaged alveolar macrophage (AM) numbers, interstitial accumulations of mast cells (MC), and alterations in the amounts of lavaged phospholipids (PL), protein (P), and histamine (H). Sham-irradiated rats served as controls. Early (1 week), dose-dependent increases in lavageable PL were not accompanied by increases in lung weights or lavageable P. Elevations in lavaged PL continued for at least 5 weeks after exposure. By this time, lung weights, AM numbers, MC, and lavageable P, but not lavageable H, were all substantially increased in lungs that received the 15 Gy dose, whereas these changes were not observed at the lower dose. At later times (weeks 7 and 9), the hyperpermeability response following the 15 Gy exposure became less pronounced and the PL response also subsided, while lung MC continued to further increase and lavageable H became abnormally elevated. Maximal increases in the lung's permeability status after the 15 Gy exposure was coincidental with maximal increases in AM. An association of increases in AM and lung hyperpermeability, however, was not evident as of week 13 after the 7.5 Gy dose when lung weights and lavageable P were significantly elevated. For the X-ray doses examined, our results suggest that: (1) the early PL response to X-rays is independent of, and precedes, permeability changes in the lung; (2) the time to onset of an X-irradiation-induced increase in lung permeability is dose-dependent; (3) the progressive accumulation of MC in the lung following X-irradiation is dose-dependent; (4) excessive accumulations of interstitial MC after X-irradiation do not necessarily result in an increase in free H; and (5) free H in the lung does not appear to play a prominent role in the hyperpermeable response. Additionally, in conjunction with the findings of other investigators, our study suggests that the MC response to X-rays may be a fundamental component of the fibrogenic response. C1 PARKE DAVIS PHARMACEUT RES,ANN ARBOR,MI. CATHOLIC UNIV NIJMEGEN,INST RADIOTHERAPY,NIJMEGEN,NETHERLANDS. RP LEHNERT, BE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. FU NCI NIH HHS [CA-37269] NR 72 TC 23 Z9 26 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD OCT PY 1991 VL 60 IS 4 BP 657 EP 675 DI 10.1080/09553009114552481 PG 19 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA GG464 UT WOS:A1991GG46400007 PM 1680146 ER PT J AU LASSILA, DH GRAY, GT AF LASSILA, DH GRAY, GT TI EFFECTS OF SHOCK PRESTRAIN ON THE DYNAMIC MECHANICAL-BEHAVIOR OF TANTALUM SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA ID STRAIN AB The effects of shock prestrain on the mechanical behavior, microstructure, and substructure of annealed tantalum have been examined. The test material was shocked to 15 GPa for 1-mu-s and soft-recovered such that deformation that occurred during this procedure was predominantly due to the shock loading. Mechanical characterization of the annealed and shock-recovered tantalum was performed over a wide range of strain rates (10(-3) to 7000 s-1) in both tension and compression. Shock prestraining caused an increase in the quasi-static yield strength of tantalum but had virtually no influence on the dynamic stress-strain response. Consistent with this, the dynamic tensile behavior of both the annealed and shock-recovered materials were nearly identical. The effects of shock prestrain on the microstructure and substructure of the test material was examined using optical and transmission electron microscopy. The results of these examinations and how they correlate with the effects of shock prestrain on mechanical behavior are discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP LASSILA, DH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 12 TC 16 Z9 16 U1 0 U2 2 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 19 EP 26 DI 10.1051/jp4:1991303 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200004 ER PT J AU STAUDHAMMER, KP AF STAUDHAMMER, KP TI PRESSURE-STRAIN-TEMPERATURE RELATIONSHIP IN SHOCK LOADED CYLINDRICAL SAMPLES OF 304 STAINLESS-STEEL SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB The residual temperature resulting from pressure-strain relationships in an axisymmetric cylindrical sample of 304 stainless steel are described. Axisymmetric implosions result in nonuniform pressure-strain-temperature combinations that need to be better understood. This paper describes each temperature contribution and the net effect on the sample. RP STAUDHAMMER, KP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MAT RES & PROC SCI GRP,MST-5,POB 1663,MS G730,LOS ALAMOS,NM 87545, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 93 EP 99 DI 10.1051/jp4:1991312 PG 7 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200013 ER PT J AU CLINE, CF REAUGH, JE AF CLINE, CF REAUGH, JE TI DYNAMIC YIELD STRENGTH OF A PALLADIUM ALLOY METALLIC-GLASS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB Taylor anvil tests in the reverse ballistic mode have been carried out to determine the dynamic yield strength of a Pd77.5Cu6.0Si16.5 metallic glass. Scanning electron microscopy has been utilized to evaluate the details of the rod and anvil interface after impact. Computer simulations have also been carried out to interpret and confirm the results and conclusions. RP CLINE, CF (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,C GRP,LIVERMORE,CA 94550, USA. NR 7 TC 3 Z9 3 U1 0 U2 3 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 139 EP 146 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200019 ER PT J AU MORAN, B GLENN, LA KUSUBOV, A AF MORAN, B GLENN, LA KUSUBOV, A TI JET PENETRATION IN GLASS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet. RP MORAN, B (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 TC 10 Z9 10 U1 0 U2 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 147 EP 154 DI 10.1051/jp4:1991319 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200020 ER PT J AU GRAY, GT MORRIS, CE AF GRAY, GT MORRIS, CE TI INFLUENCE OF LOADING PATHS ON THE MECHANICAL RESPONSE AND SUBSTRUCTURE EVOLUTION OF SHOCK-LOADED COPPER SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB Shock recovery experiments on copper have been conducted to investigate the influence of loading rate and stress amplitude on defect storage and post-shock mechanical properties. The shock risetimes varied approximately from one nanosecond for the shock experiments to one microsecond for quasi-isentropic loading experiments. All the experiments had the same peak pressure and pulse duration. Attaining a peak pressure of 10 GPa through multiple shocks or a single shock produced similar results for defect storage and post-shock yield strength. Decreasing the strain-rate of loading is shown to increase both the defect storage and post-shock yield strength of copper. The effect of loading rate on post-shock substructure and mechanical response of impacted copper is postulated to be directly related to the amount of dislocation motion before interaction with other dislocations and to the amount of reversible dislocation motion and resultant annihilation during the rarefaction portion of the shock-release cycle. RP GRAY, GT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 10 TC 7 Z9 7 U1 0 U2 3 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 191 EP 196 DI 10.1051/jp4:1991325 PG 6 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200026 ER PT J AU JOHNSON, JN LOMDAHL, PS AF JOHNSON, JN LOMDAHL, PS TI ANELASTIC RELEASE FROM THE SHOCK-COMPRESSED STATE SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB Anelastic release from the shock-compressed state is analyzed in terms of internal self stresses acting on dislocation pile-ups and pinned dislocation loops. Reverse anelastic deformation occurs immediately upon release due to these internal stresses and is responsible for departure from ideal elastic-plastic unloading wave behavior: anelastic release is commonly observed in all shock-loaded metals. The rate at which this readjustment of internal stress occurs is determined by the viscous drag coefficient in the shock-compressed state and has important consequences regarding determination of elastic moduli from unloading wave data. RP JOHNSON, JN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 223 EP 228 DI 10.1051/jp4:1991330 PG 6 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200031 ER PT J AU LAWRENCE, RJ TROTT, WM AF LAWRENCE, RJ TROTT, WM TI A SIMPLE-MODEL FOR THE MOTION OF PULSED-LASER-DRIVEN THIN FLYERS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB A model that predicts the final velocity of high-power, pulsed-laser-driven thin flyers is described. The required input parameters can either be obtained from standard handbooks or simply extracted from one set of data. The model yields a number of features and scaling laws that are well verified by experiment. Specific comparisons of model predictions with experimental results illustrate excellent agreement for variations of laser fluence and pulse width as well as flyer diameter and thickness. RP LAWRENCE, RJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 4 TC 3 Z9 5 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 453 EP 458 DI 10.1051/jp4:1991364 PG 6 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200065 ER PT J AU ZUREK, AK GRAY, GT AF ZUREK, AK GRAY, GT TI DYNAMIC STRENGTH AND STRAIN RATE EFFECTS ON FRACTURE-BEHAVIOR OF TUNGSTEN AND TUNGSTEN ALLOYS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB An investigation of the stress-strain response as a function of strain rate, spall strength, and dynamic fracture behavior of pure W, W-26Re, W-Ni-Fe and W-Ni-Fe-Co has been performed. Spall strength measurements, obtained in symmetric-impact tests, showed an increase in spall strength from 0.4 GPa for pure tungsten to 3.8 GPa for 90W-7Ni-3Fe. Concurrent with the increase in spall strength was a change in fracture mode from cleavage (for pure W) to a mixture of transgranular and intergranular fracture for the alloyed systems. Compression testing performed at strain rates from 10(-3) s-1 to 3000 s-1 showed that pure tungsten exhibits a large strain rate sensitivity and almost no work hardening at tested strain rates. In contrast, W-26Re and W-Ni-Fe-Co displayed significant work hardening at all strain rates. RP ZUREK, AK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87544, USA. NR 12 TC 12 Z9 12 U1 1 U2 3 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 631 EP 637 DI 10.1051/jp4:1991388 PG 7 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200089 ER PT J AU GRADY, DE AF GRADY, DE TI DYNAMICS OF ADIABATIC SHEAR SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA ID BANDS; LOCALIZATION; INSTABILITY; GROWTH AB The formation of adiabatic shear bands is examined with an approximate analytic model. The shear band is viewed as a propagating feature with a well-defined front. The shear band is further partition into a shear-band process zone within which most of the adiabatic heating and shear stress relaxation occurs, followed by a quasi-steady zone within which little dissipation occurs. Although a one-dimensional analysis of the shear-band dynamics is initially pursued, the analysis is then used to calculate properties of the inherently two-dimensional shear-band process zone. The length and width of the process zone is calculated along with the shear displacement. The model is further used to calculate the energy dissipation within the shear-band process zone. The flow field within the vicinity of the process zone is also examined. Calculated properties of the shear-band process zone are compared with available experimental data. RP GRADY, DE (reprint author), SANDIA NATL LABS,ORG 1543,ALBUQUERQUE,NM 87185, USA. NR 20 TC 4 Z9 4 U1 0 U2 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 653 EP 660 DI 10.1051/jp4:1991391 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200092 ER PT J AU ATTIA, AV AF ATTIA, AV TI THE EFFECT OF FRICTION ON SIMULATED DYNAMIC FRACTURING OF ROCKS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB During underground nuclear tests, rocks may fail by plastic yielding, which limits shear strength, or by tensile fracture, wherever maximum principal stress exceeds tensile strength. A third mode of failure exists due to friction along closed fractured surfaces. There, friction affects slipping and can thus limit stress. In this paper, we study the effect of friction on the simulated dynamic response of rocks to underground nuclear explosions. The coefficient of friction is the ratio of total shear stress applied to a closed fracture surface to normal applied compressive total stress. At low coefficients of friction, the evolving stress field tends to be weakened by frictional slip, which also eases closing of fractures. At high coefficients of friction, the stress field tends to be strengthened, where fractures have closed, but remains weak, where fractures are left open. RP ATTIA, AV (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,L-200,LIVERMORE,CA 94550, USA. NR 4 TC 1 Z9 1 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 745 EP 750 DI 10.1051/jp4:19913105 PG 6 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200106 ER PT J AU STEINBERG, DJ AF STEINBERG, DJ TI COMPUTER STUDIES OF THE DYNAMIC STRENGTH OF CERAMICS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA ID PARTIALLY STABILIZED ZIRCONIA; CONSTITUTIVE MODEL; LOADING RATE; TEMPERATURE; FRACTURE; FLOW AB Using a new constitutive model, computer studies were performed concerning the dynamic yield strength of six ceramics, SiC, TiB2, AlN, two types of B4C, and partially stabilized zirconia. The relative importance of the thermomechanical variables, strain, strain-rate, pressure, and temperature, as well as the Bauschinger effect, is demonstrated in determining the time response of ceramics to high-strain-rate deformation. The constitutive model is easy to implement in a hydrodynamic computer code and successfully reproduces a variety of data for these materials. RP STEINBERG, DJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808 L35,LIVERMORE,CA 94550, USA. NR 16 TC 15 Z9 16 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 837 EP 844 DI 10.1051/jp4:19913117 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200118 ER PT J AU DEY, TN AF DEY, TN TI CONSTITUTIVE MODEL FOR GEOLOGICAL AND OTHER POROUS MATERIALS UNDER DYNAMIC LOADING SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB An effective stress model is described for use in numerical calculations on porous materials which are partially or fully saturated with water. The flow rule chosen for the shear failure portion of the model is examined and shown to have a significant influence on wave propagation results. A flow rule which produces dilatancy results in less attenuation than a rule producing shear-enhanced void collapse. The dilatancy producing rule is less prone to producing liquefaction and results in significantly higher stress levels behind the wave front. RP DEY, TN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GEOANAL GRP,MAIL STOP F665,POB 1663,LOS ALAMOS,NM 87544, USA. NR 8 TC 0 Z9 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 845 EP 852 DI 10.1051/jp4:19913118 PG 8 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200119 ER PT J AU MURPHY, MJ CLINE, CF AF MURPHY, MJ CLINE, CF TI MODELING OF SHOCK-WAVE AND DYNAMIC INTERACTIONS ON PC BASED COMPUTERS SO JOURNAL DE PHYSIQUE III LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON MECHANICAL AND PHYSICAL BEHAVIOUR OF MATERIALS UNDER DYNAMIC LOADING ( DYMAT 91 ) CY OCT 14-18, 1991 CL STRASBOURG, FRANCE SP MINIST DEF FRANCE, MINIST RECH & TECHNOL FRANCE, MINIST AFFAIRES ETRANGERES FRANCE, DELEGAT GEN ARMEMENT, CNRS, CEA AB The implementation and utility of 80386/80486 personal computer (PC) versions of the Lawrence Livermore National Laboratory developed DYNA and NIKE finite element codes are described and evaluated in this paper. These code conversions provide for the PC modeling of problems that are currently analyzed on mainframes, mini-computers, and workstations. A comprehensive conversion of the entire source code allows for simulation of all problems that can be run on the CRAY, VMS, and UNIX systems. Some advantages of this approach are lower hardware and software costs, a convenient upgrade path for existing PC users, and simplicity for novice or casual users that do not have the time or inclination to learn UNIX. In addition, low cost speed improvements are easily implemented with the addition of the 3167/4167 numeric co-processors from Weitek or with the more expensive board-based I-860 chip options. RP MURPHY, MJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD OCT PY 1991 VL 1 IS C3 BP 879 EP 885 DI 10.1051/jp4:19913123 PG 7 WC Physics, Multidisciplinary SC Physics GA GG302 UT WOS:A1991GG30200124 ER PT J AU SEEGER, PA HJELM, RP AF SEEGER, PA HJELM, RP TI SMALL-ANGLE NEUTRON-SCATTERING AT PULSED SPALLATION SOURCES SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL CONF ON SMALL ANGLE SCATTERING CY AUG 06-09, 1990 CL UNIV LOUVAIN, LOUVAIN, BELGIUM SP NATL SCI FDN BELGIUM, UNIV LOUVAIN, PHILIPS, DOW CHEM, EXXON CHEM INT, SIEMENS, SOLVAY, MAES, ICI, RAYCHEM HO UNIV LOUVAIN ID RESOLUTION; DIFFRACTOMETERS; TRANSMISSION; SPECTROMETER; OPTIMIZATION AB The importance of small-angle neutron scattering (SANS) in biological, chemical, physical and engineering research mandates that all intense neutron sources be equipped with SANS instruments. Four existing instruments at pulsed sources are described and the general differences between pulsed-source and reactor-based instrument designs are discussed. The basic geometries are identical, but dynamic range is generally achieved by using a broad band of wavelengths (with time-of-flight analysis) rather than by moving the detector. This allows optimization for maximum beam intensity at a given beam size over the full dynamic range with fixed collimation. Data-acquisition requirements at a pulsed source are more severe, requiring large fast histograming memories. Data reduction is also more complex, as all wavelength-dependent and angle-dependent backgrounds and nonlinearities must be accounted for before data can be transformed to intensity vs momentum transfer (Q). A comparison is shown between the Los Alamos pulsed instrument and D11 (Institut Laue-Langevin) and examples from the four major topics of the conference are shown. The general conclusion is that reactor-based instruments remain superior at very low Q or if only a narrow range of Q is required, but that the current generation of pulsed-source instruments is competitive at moderate Q and may be faster when a wide range of Q is required. RP SEEGER, PA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545, USA. RI Lujan Center, LANL/G-4896-2012 NR 35 TC 45 Z9 45 U1 1 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT 1 PY 1991 VL 24 BP 467 EP 478 DI 10.1107/S0021889891004764 PN 5 PG 12 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GL629 UT WOS:A1991GL62900006 ER PT J AU WIGNALL, GD AF WIGNALL, GD TI INSTRUMENTAL RESOLUTION EFFECTS IN SMALL-ANGLE SCATTERING SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL CONF ON SMALL ANGLE SCATTERING CY AUG 06-09, 1990 CL UNIV LOUVAIN, LOUVAIN, BELGIUM SP NATL SCI FDN BELGIUM, UNIV LOUVAIN, PHILIPS, DOW CHEM, EXXON CHEM INT, SIEMENS, SOLVAY, MAES, ICI, RAYCHEM HO UNIV LOUVAIN ID X-RAY-SCATTERING; NEUTRON-SCATTERING; COLLIMATION; TRANSITION; FACILITY AB Experimentally measured scattering data differ from theoretical curves because of departures from point geometry in a real instrument. In a small-angle scattering instrument there are three contributions to the smearing of an ideal curve: (1) the angular divergence of the beam; (2) the finite resolution of the detector; and (3) the polychromatic nature of the beam. In general, instrumental-resolution (smearing) effects are smaller for small-angle neutron scattering (SANS) than for small-angle X-ray scattering (SAXS). This is because most SANS experiments are performed in point geometry (with pinhole collimation) whereas a significant proportion of X-ray experiments have used long-slit sources where smearing effects are much larger, particularly at small angles. Hence, corrections to the measured curve are often applied in SAXS experiments to compensate for angular smearing. Less attention has been given to the effects of wavelength smearing in SAXS which is often assumed to be negligible. Similarly, SANS data are routinely analyzed without reference to instrumental smearing effects. The circumstances under which the above assumptions break down are illustrated by a range of experiments comparing data taken from the same samples, run on different types of SAXS and SANS facilities. These experiments indicate some circumstances under which the above effects cannot be neglected. RP WIGNALL, GD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. OI Wignall, George/0000-0002-3876-3244 NR 37 TC 16 Z9 17 U1 4 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT 1 PY 1991 VL 24 BP 479 EP 484 DI 10.1107/S0021889891003278 PN 5 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GL629 UT WOS:A1991GL62900007 ER PT J AU RICE, M WAKATSUKI, S BIENENSTOCK, A AF RICE, M WAKATSUKI, S BIENENSTOCK, A TI COMPOSITION MODULATION IN AMORPHOUS METAL GERMANIUM ALLOYS DETECTED BY ANOMALOUS SMALL-ANGLE X-RAY-SCATTERING SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL CONF ON SMALL ANGLE SCATTERING CY AUG 06-09, 1990 CL UNIV LOUVAIN, LOUVAIN, BELGIUM SP NATL SCI FDN BELGIUM, UNIV LOUVAIN, PHILIPS, DOW CHEM, EXXON CHEM INT, SIEMENS, SOLVAY, MAES, ICI, RAYCHEM HO UNIV LOUVAIN AB The tunability of synchrotron radiation was used to perform anomalous small-angle X-ray scattering (ASAXS) experiments on amorphous metal-germanium (a-MxGe100-x) alloys with the aim of detecting and characterizing composition modulation and phase separation. The combination of SAXS with the anomalous-dispersion effect allows the composition modulation to be distinguished from density fluctuations arising from voids and defects. Data gathered from a-FexGe100-x, a-WxGe100-x and a-MoxGe100-x samples in the low metal concentration regime show nanometer-scale composition modulation. In these samples the density of Ge atoms is uniform throughout. The small-angle X-ray scattering arises from fluctuations in the density of metal atoms. The position of the SAXS peak moves towards smaller values of the scattering vector with increased metal concentration indicating an increase in the correlation length of the composition fluctuations with increased metal content. C1 STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94309. RP RICE, M (reprint author), STANFORD UNIV,DEPT ELECT ENGN,STANFORD,CA 94305, USA. NR 8 TC 10 Z9 10 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT 1 PY 1991 VL 24 BP 598 EP 602 DI 10.1107/S0021889890013334 PN 5 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GL629 UT WOS:A1991GL62900026 ER PT J AU PAHL, R BONSE, U PEKALA, RW KINNEY, JH AF PAHL, R BONSE, U PEKALA, RW KINNEY, JH TI SAXS INVESTIGATIONS ON ORGANIC AEROGELS SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 8TH INTERNATIONAL CONF ON SMALL ANGLE SCATTERING CY AUG 06-09, 1990 CL UNIV LOUVAIN, LOUVAIN, BELGIUM SP NATL SCI FDN BELGIUM, UNIV LOUVAIN, PHILIPS, DOW CHEM, EXXON CHEM INT, SIEMENS, SOLVAY, MAES, ICI, RAYCHEM HO UNIV LOUVAIN ID SCATTERING AB Structural properties of organic aerogels were studied by ultra-small-angle X-ray scattering (USAXS) at the Synchrotron Radiation Laboratory HASYLAB at DESY, Hamburg, Germany. The organic aerogels were synthesized from the base-catalyzed sol-gel polymerization of resorcinol with formaldehyde (RF) followed by a supercritical drying process. RF aerogels are low-density materials with a solid matrix composed of interconnected colloidal-like particles. Scattering experiments were carried out using a crystal camera optimized for ultra-small-angle X-ray scattering with synchrotron radiation. The measured SAXS profiles revealed a scattering power depending upon synthetic conditions of the gels. RF aerogels were found to be homogeneous at length scales greater than 20 nm. From Guinier plots, radii of gyration R(g) of 3-20 nm were computed. R(g) appears to be a measure of the pore (cell) size. Although fractal silica aerogels show similar characteristics, fractal behavior of the organic aerogels is uncertain. These materials are best described as random aggregates of smooth colloidal-like particles with open-cell porosity. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT CHEM & MAT SCI,LIVERMORE,CA 94550. RP PAHL, R (reprint author), UNIV DORTMUND,INST PHYS,POSTFACH 500500,W-4600 DORTMUND,GERMANY. NR 15 TC 21 Z9 22 U1 1 U2 7 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT 1 PY 1991 VL 24 BP 771 EP 776 DI 10.1107/S0021889890011815 PN 5 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA GL629 UT WOS:A1991GL62900052 ER PT J AU HISKES, JR AF HISKES, JR TI CROSS-SECTIONS FOR THE VIBRATIONAL-EXCITATION OF THE H-2 X1-SIGMA-G+(V) LEVELS GENERATED BY ELECTRON COLLISIONAL EXCITATION OF THE HIGHER SINGLET-STATES SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ORBITER ULTRAVIOLET SPECTROMETER; MOLECULAR-HYDROGEN; IMPACT EXCITATION; TRANSITION-PROBABILITIES; CALIBRATION SOURCE; REFERENCE SPECTRA; BAND SYSTEMS; DISSOCIATION; PREDISSOCIATION AB The excitation cross sections, sigma(upsilon,upsilon"), for an H-2 molecule initially in any one of the 15 vibrational levels, upsilon belonging to the ground electronic state and excited to a final vibrational level, upsilon" are evaluated for direct excitations via all members of the excited electronic singlet spectrum. Account is taken of predissociation, autoionization, and radiative decay of the excited electronic spectrum that leads to a final population distribution for the ground electronic state, X 1-SIGMA-g+ (upsilon"). For upsilon = 0, account is taken explicity of transitions via the B, C, B', and D electronic states in evaluating the cross sections. The additional contribution of excitations via all Rydberg states lying above the D state enhances these cross sections by approximately 10%. For upsilon > 0, cross sections are evaluated taking explicit account of transitions through the B and C states; higher singlet excitations enhance these values by 25%. The choice of the reference total cross sections remains a subjective one, causing the values calculated here to have a possible uncertainty of -30%(+20%). For excitations occurring within a hydrogen discharge, collisional excitation-ionization events among the intermediate singlet states will effectively quench the upsilon, upsilon" excitation process for discharge densities in excess of the range 10(15)-10(16) electrons/cm-3. RP HISKES, JR (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NR 32 TC 45 Z9 45 U1 0 U2 0 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 OCT 1 PY 1991 VL 70 IS 7 BP 3409 EP 3417 DI 10.1063/1.349284 PG 9 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500003 ER PT J AU DICK, JJ MULFORD, RN SPENCER, WJ PETTIT, DR GARCIA, E SHAW, DC AF DICK, JJ MULFORD, RN SPENCER, WJ PETTIT, DR GARCIA, E SHAW, DC TI SHOCK RESPONSE OF PENTAERYTHRITOL TETRANITRATE SINGLE-CRYSTALS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID NITROMETHANE; DEFORMATION; INITIATION; SOLIDS AB The shock response of single crystals of the explosive pentaerythritol tetranitrate was studied from 3.4 to 19 GPa. Four orientations, <110>, <001>, <101>, and <100> were studied. The shock Hugoniot and shock initiation sensitivities were measured in wedge tests. Intermediate velocity transitions were noted. A sensitivity anomaly near 4 GPa was discovered for <110> orientations. Chemiluminescent phenomena associated with this anomaly were studied using framing photography and uv/visible spectroscopy. Both plane-wave explosive and gas-gun impact experiments were done. Analysis of the steric hindrance occurring during edge dislocation motion in the shear flow associated with shock-induced uniaxial strain was done. The results corroborate the hypothesis that the orientation dependence of shock initiation sensitivity is due to the anisotropy of plastic flow, that is, the relative ease of slip in different orientations. RP DICK, JJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 51 TC 127 Z9 134 U1 2 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1991 VL 70 IS 7 BP 3572 EP 3587 DI 10.1063/1.349253 PG 16 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500025 ER PT J AU KORTRIGHT, JB AF KORTRIGHT, JB TI NONSPECULAR X-RAY-SCATTERING FROM MULTILAYER STRUCTURES SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Nonspecular x-ray (lambda = 0.154 nm) scattering from a 3.9-nm-period tungsten/carbon multilayer structure with scattering vectors near low-angle multilayer specular interference peaks is reported. Diffuse intensity results from kinematical small-angle scattering from in-plane structural inhomogeneities associated with the individual interfaces or layers having characteristic length scales much greater than the multilayer period. Modulations in this diffuse nonspecular intensity when the incident or observation angle is equal to the angle of the first-order multilayer Bragg peak result from standing-wave-enhanced scattering and other dynamical effects. The technique provides a sensitive measure of in-plane structural inhomogeneities of heterointerface systems. RP KORTRIGHT, JB (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720, USA. NR 25 TC 86 Z9 87 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1991 VL 70 IS 7 BP 3620 EP 3625 DI 10.1063/1.349259 PG 6 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500031 ER PT J AU THAKUR, RPS SINGH, R NELSON, AJ SWARTZLANDER, AB AF THAKUR, RPS SINGH, R NELSON, AJ SWARTZLANDER, AB TI ROLE OF INSITU RAPID ISOTHERMAL PROCESSING IN ADVANCED III-V-TECHNOLOGY SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PHASE EPITAXIAL-GROWTH AB Rapid isothermal processing (RIP) based on incoherent sources of light is emerging as a reduced thermal budget (product of processing time and temperature) processing technique. As compared to stand alone annealing unit, the in situ RIP unit is very attractive for the next generation of devices. A number of unwanted physical phenomena can be suppressed or completely eliminated in the in situ RIP case leading to improved quality of materials when compared to their ex situ rapid isothermal annealed and furnace annealed counterparts. We have used in situ rapid isothermal processor for the in situ rapid isothermal chemical cleaning of InP and GaAs substrates and in situ metallization of InP and GaAs Schottky diodes. As compared to ex situ annealing, the negligible oxygen content at the surface and interface of in situ RIP samples result in better current-voltage characteristics, lower and compressive stress values, as well as smooth and continuous morphologies of the ohmic contact. In this paper, we have highlighted the role of in situ RIP in the metallization of InP and GaAs devices. C1 CLEMSON UNIV,DEPT ELECT & COMP,CLEMSON,SC 29634. SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP THAKUR, RPS (reprint author), UNIV OKLAHOMA,SCH ELECT ENGN & COMP SCI,NORMAN,OK 73019, USA. NR 6 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1991 VL 70 IS 7 BP 3857 EP 3861 DI 10.1063/1.349191 PG 5 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500070 ER PT J AU GRACE, JM MCDONALD, DB REITEN, MT OLSON, J KAMPWIRTH, RT GRAY, KE AF GRACE, JM MCDONALD, DB REITEN, MT OLSON, J KAMPWIRTH, RT GRAY, KE TI SELECTIVE RESPUTTERING OF BISMUTH IN SPUTTERED BI-SR-CA-CU-O FILMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GROWTH AB We present studies using a dc magnetron in an on-axis configuration to sputter Bi-Sr-Ca-Cu-O films from a composite target. These studies show that bismuth can be preferentially resputtered. The influence of ozone, molecular oxygen, and total pressure on the resputtering of bismuth is investigated and discussed. Ozone, in low concentrations, can dramatically affect the degree of resputtering. By comparing the effects of molecular oxygen and ozone, some insight is gained regarding the possible mechanisms of negative ion formation in the magnetron environment. Based on our results we suggest that molecular oxygen can bring about resputtering primarily by forming O2+, which collides with the target to produce energetic negative oxygen ions. In contrast, ozone may form negative ions by electron impact in the dark space above the target, giving rise to lower-energy negative ions, which can traverse the plasma unneutralized and can be stopped with an applied bias on the sample block. With no added oxidant, negative oxygen ions from the target oxygen may dominate the background resputtering. Similarity is found between our results and those for similar studies on Y-Ba-Cu-O by other workers. Bismuth in Bi-Sr-Ca-Cu-O behaves as barium in Y-Ba-Cu-O with regards to preferential resputtering; furthermore, the response of strontium, calcium, and copper to oxygen in sputtered Bi-Sr-Ca-Cu-O is similar to what is observed for copper in Y-Ba-Cu-O. RP GRACE, JM (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 14 TC 8 Z9 8 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 OCT 1 PY 1991 VL 70 IS 7 BP 3867 EP 3875 DI 10.1063/1.349193 PG 9 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500072 ER PT J AU GAI, W HO, CH AF GAI, W HO, CH TI MODELING OF THE TRANSVERSE-MODE SUPPRESSOR FOR DIELECTRIC WAKE-FIELD ACCELERATOR SO JOURNAL OF APPLIED PHYSICS LA English DT Note AB An analytical model is given for the transverse mode suppressor of dielectric wake-field accelerators. The calculated results are compared with recent experimental data. RP GAI, W (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 5 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 OCT 1 PY 1991 VL 70 IS 7 BP 3955 EP 3957 DI 10.1063/1.349181 PG 3 WC Physics, Applied SC Physics GA GJ675 UT WOS:A1991GJ67500088 ER PT J AU PAULSEN, MD BASS, MB ORNSTEIN, RL AF PAULSEN, MD BASS, MB ORNSTEIN, RL TI ANALYSIS OF ACTIVE-SITE MOTIONS FROM A 175-PICOSECOND MOLECULAR-DYNAMICS SIMULATION OF CAMPHOR-BOUND CYTOCHROME-P450CAM SO JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS LA English DT Article ID CRYSTAL-STRUCTURE; CYTOCHROME-P-450CAM; HYDROXYLATION AB The structure and internal motions of the active site residues of camphor-bound cytochrome P450cam have been evaluated on the basis of a 175 psec molecular dynamics simulation. The active site residues generally show very small deviations away from their starting crystal positions. These residues also generally show much smaller fluctuations than for the enzyme as a whole. Phe 87 is dynamically very unusual and is suggested to play a role in substrate movement into and/or out of the active site. The average distance between the heme iron and atoms C5, C6, and C3 of camphor is 5.3, 6.0, and 7.0 angstrom, respectively. This trend is consistent with the experimentally observed stereospecificity of the hydroxylation reaction. On the basis of distance and angle criteria, both 5-exo and 5-endo hydrogen abstraction are predicted to occur during the hydroxylation reaction; although the 5-exo pathway is expected to be 3-fold more likely. C1 PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NR 24 TC 34 Z9 34 U1 0 U2 0 PU ADENINE PRESS INC PI GUILDERLAND PA PO BOX 355/340, GUILDERLAND, NY 12084 SN 0739-1102 J9 J BIOMOL STRUCT DYN JI J. Biomol. Struct. Dyn. PD OCT PY 1991 VL 9 IS 2 BP 187 EP 203 PG 17 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GL928 UT WOS:A1991GL92800001 PM 1741957 ER PT J AU LAURSEN, SL CARTLAND, HE AF LAURSEN, SL CARTLAND, HE TI MULTIPLICITY DEPENDENCE OF MATRIX-INDUCED FREQUENCY-SHIFTS FOR ATOMIC TRANSITIONS OF THE GROUP 12 METALS IN RARE-GAS SOLIDS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID KRYPTON MATRIX; SPECTROSCOPIC CHARACTERIZATION; PHOTOSENSITIZED CHEMISTRY; INTERATOMIC POTENTIALS; ABSORPTION-SPECTRA; P-3 HG; STATES; CLUSTERS; HALIDES; ZNAR AB Atomic resonances of the group 12 metal atoms, Hg, Cd, and Zn, undergo frequency shifts from the gas phase atomic line when trapped in rare gas matrices of Ar, Kr, and Xe at 12 K. As expected, the shifts are approximately linear in polarizability of the rare gas, but the slope of this line depends on whether the transition in question is 1P1 <-- 1S0 or 3P1 <-- 1S0. Thus the matrix-induced frequency shift is dependent on the singlet or triplet nature of the excited state as well as on the matrix material. This dependence on multiplicity is discussed in terms of interactions between the excited-state atomic orbitals and the matrix. The results are compared to matrix studies of other metals and to related gas-phase work on diatomic van der Waals complexes of group 12 metals with rare gases. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CHEM BIODYNAM LAB,BERKELEY,CA 94720. OI LAURSEN, SANDRA/0000-0002-4327-9887 NR 42 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 4751 EP 4755 DI 10.1063/1.461750 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600002 ER PT J AU TUMINELLO, PS ARAKAWA, ET INAGAKI, T PARKS, JE AF TUMINELLO, PS ARAKAWA, ET INAGAKI, T PARKS, JE TI OPTICAL-RESPONSE OF LIQUID MERCURY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SURFACE PLASMONS; REFLECTANCE; METALS AB In many of the results of previous investigations, systematic differences have been observed in the directly measured reflectances of liquid Hg and those calculated from the optical constants determined by ellipsometry. We have performed a comprehensive set of experiments on liquid Hg at room temperature in order to resolve the problem of whether these discrepancies are real. A summary of some of our results have been published [Phys. Rev. B 40, 11994 (1989)]. Here we present a more detailed account of the experimental details and some new results. The spectral range of these experiments was confined to the visible spectral region. Normal-incidence reflectances of liquid Hg under vacuum and in contact with dielectric overlayers were measured. Reflectances of polarized light were measured at a photon angle of incidence of 70-degrees for liquid Hg under vacuum. The optical constants of liquid Hg in contact with various dielectric overlayers were determined by ellipsometry and also by measuring reflectances as a function of angle of photon incidence at a MgF2-Hg interface. The results of the direct reflectance measurements were consistent with the optical properties determined by ellipsometry. No evidence was found for transition layers on the surface of liquid Hg. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. OSAKA KYOIKU UNIV,DEPT PHYS,OSAKA 543,JAPAN. RP TUMINELLO, PS (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831, USA. NR 44 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 4791 EP 4795 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600008 ER PT J AU NOURBAKHSH, S NORWOOD, K YIN, HM LIAO, CL NG, CY AF NOURBAKHSH, S NORWOOD, K YIN, HM LIAO, CL NG, CY TI VACUUM ULTRAVIOLET PHOTODISSOCIATION AND PHOTOIONIZATION STUDIES OF CH3SCH3 AND CH3S SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID METASTABLE ION CHARACTERISTICS; PHOTOELECTRON COINCIDENCE; DIMETHYL SULFIDE; COLLISIONAL ACTIVATION; MOLECULES; THIOFORMALDEHYDE; DISSOCIATION; ENERGIES; SULFUR; CH2SH+ AB We have measured the translational energy releases of the laser photodissociation processes CH3SCH3 + h-nu (193 nm) --> CH3 + CH3S [process (1)] and CH3SCH2 + H [process (2)]; and CH3S + h-nu (193 nm) --> S + CH3 [process (3)]. The onsets of the translational energy distributions for photofragments of processes (1) and (2) allow the direct determination of 74.9 +/- 1.5 and 91 +/- 2.5 kcal/mol for the dissociation energies of the CH3-SCH3 and H-CH2SCH3 bonds at 0 K, respectively. The threshold observed for S formed by process (3) is consistent with the conclusion that the production of S(3P) is small compared to S(1D). The photoelectron-photoion coincidence (PEPICO) spectra for CH3SCH3+, CH3SCH2+, CH3S+ (or CH2SH+), and CH2S+ resulting from photoionization of CH3SCH3 have been measured in the wavelength region of 900-1475 angstrom. The PEPICO study allows the construction of a detailed breakdown diagram for the formation of CH3SCH2+, CH3S+ (or CH2SH+), and CH2S+ from energy-selected CH3SCH3+ ions. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP NOURBAKHSH, S (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 45 TC 65 Z9 67 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 5014 EP 5023 DI 10.1063/1.461717 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600030 ER PT J AU SZCZESNIAK, MM KENDALL, RA CHALASINSKI, G AF SZCZESNIAK, MM KENDALL, RA CHALASINSKI, G TI ABINITIO STUDY OF THE NONADDITIVE EFFECTS IN THE TRIMER OF AMMONIA SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTERACTION ENERGY; MOLECULAR MECHANICS; PERTURBATION-THEORY; BASIS-SETS; CLUSTERS; DIMER; REPULSION; ATOMS; NH3 AB The three-body potential in the trimer of ammonia is analyzed in terms of Heitler-London (HL)-exchange, self-consistent field (SCF)-deformation, induction, and dispersion nonadditivities. The nonadditive term is due largely to the SCF-deformation effect. However, its anisotropy resembles more that of the HL-exchange nonadditivity. Correlation effects do not contribute significantly to the nonadditivity. The trimer is of C3h symmetry. The geometry is determined at the level of pairwise interactions. Apart from a slight shortening of the N-N distance, the three-body effect has virtually no influence on the mutual orientations of subsystems in the trimer. Nonadditive properties of ammonia are compared to those of other trimers: (HF)3; (HCl)3; (H2O)3; and (CH4)3. An examination of the basis set dependence of the components of three-body effect leads us to believe that the present treatment yields three-body potential with accuracy better than 0.1 kcal/mol for the trimer of ammonia, as well as for other polar trimers. C1 SO ILLINOIS UNIV, DEPT CHEM & BIOCHEM, CARBONDALE, IL 62901 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, MOLEC SCI SOFTWARE GRP, RICHLAND, WA 99352 USA. UNIV WARSAW, DEPT CHEM, PL-02093 WARSAW, POLAND. NR 42 TC 38 Z9 39 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 5169 EP 5178 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600047 ER PT J AU NOVOA, JJ TARRON, B WHANGBO, MH WILLIAMS, JM AF NOVOA, JJ TARRON, B WHANGBO, MH WILLIAMS, JM TI INTERACTION ENERGIES ASSOCIATED WITH SHORT INTERMOLECULAR CONTACTS OF C-H BONDS - ABINITIO COMPUTATIONAL STUDY OF THE C-H...O CONTACT INTERACTION IN CH4...OH2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID WATER HYDROCARBON INTERACTIONS; INFRARED MATRIX-ISOLATION; HYDROGEN-BONDS; MOLECULAR-INTERACTIONS; BASIS-SETS; SYSTEMS; ACETYLENE; COMPLEX; METHANE; BASES AB To accurately evaluate the C-H...O contact interaction energy, ab initio calculations were performed on CH4...OH2 at the self-consistent-field molecular orbital (SCF-MO) and MP2 levels with various quality basis sets including a near Hartree-Fock limit (HFL) one. The interaction energies calculated with truncated basis sets have small basis set superposition errors and become close to the near HFL results only when they include diffuse functions. This is attributed to the necessity of properly representing the lone pair electrons of oxygen that make short contact interaction with the C-H bond. Our MP2 calculations suggest that the conformation of CH4...OH2 with one C-H...O contact is the only minimum-energy structure. At the MP2 level with the near HFL basis set, the binding energy of CH4...OH2 is calculated to be 0.59 +/- 0.05 kcal/mol. The potential energy curves of CH4...OH2 calculated as functions of the H...O contact angles are consistent with the observation that the most frequently found H...O contact angles of organic solids are in the range \phi\ less-than-or-equal-to approximately 60-degrees and \theta\ less-than-or-equal-to approximately 30-degrees. C1 N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP NOVOA, JJ (reprint author), UNIV BARCELONA,FAC QUIM,DEPT QUIM FIS,E-08028 BARCELONA,SPAIN. RI Novoa, Juan/B-3525-2013 OI Novoa, Juan/0000-0003-3577-1182 NR 37 TC 93 Z9 96 U1 1 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 5179 EP 5186 DI 10.1063/1.461686 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600048 ER PT J AU NELLIS, WJ MITCHELL, AC REE, FH ROSS, M HOLMES, NC TRAINOR, RJ ERSKINE, DJ AF NELLIS, WJ MITCHELL, AC REE, FH ROSS, M HOLMES, NC TRAINOR, RJ ERSKINE, DJ TI EQUATION OF STATE OF SHOCK-COMPRESSED LIQUIDS - CARBON-DIOXIDE AND AIR SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID REPULSIVE FORCES; DENSE ARGON; SOLID CO2; ELECTRICAL-CONDUCTIVITY; DETONATION PROPERTIES; FLUID NITROGEN; HIGH-DENSITIES; 900 KBAR; PRESSURE; MIXTURES AB Equation-of-state data were measured for liquid carbon dioxide and air shock-compressed to pressures in the range 28-71 GPa (280-710 kbar) using a two-stage light-gas gun. The experimental methods are described. The data indicate that shock-compressed liquid CO2 decomposes at pressures above 34 GPa. Liquid air dissociates above a comparable shock pressure, as does liquid nitrogen. Theoretical intermolecular potentials are derived for CO2 from the data. The calculated shock temperature for the onset of CO2 decomposition is 4500 K at a volume of 17 cm3/mol. RP NELLIS, WJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 34 TC 35 Z9 37 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 5268 EP 5272 DI 10.1063/1.461665 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600059 ER PT J AU BRADLEY, KF CHEN, SH BRUN, TO AF BRADLEY, KF CHEN, SH BRUN, TO TI QUASI-ELASTIC NEUTRON-SCATTERING MEASUREMENTS OF N-BUTANE IN ITS CRYSTALLINE, PLASTIC, AND LIQUID-PHASES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; CONDENSED PHASES; TRANSITIONS; HEXANE AB We report here measurements of quasielastic neutron scattering from n-butane at temperatures of 90, 115, 125 and 190 K and in a momentum transfer range of 0.8-2.4 angstrom-1. These measurements confirm that between 115 and 125 K butane forms a plastic crystal in which the centers of mass of the butane molecules form a crystalline structure, but the individual molecules are free to rotate. At these two intermediate temperatures, there exists both an elastic peak, characteristic of a solid structure, and quasielastic components arising from the rotational motions of the butane molecules. At 90 K, the butane scatters neutrons only elastically, while at 190 K, the butane scatters neutrons only quasielastically. In both the plastic and the liquid phases, the presence of at least two quasielastic processes must be assumed in order to explain the measurements. In the plastic crystal, we associate a broad Lorentzian component with intramolecular reorientations about the central carbon-carbon bond and a second, relatively narrow, Lorentzian component with whole molecule rotations. The latter process gives rise to a rotational quasielastic peak having a width of 400-mu-eV, which is constant to within the instrumental resolution of 70-mu-eV at both temperatures and at all measured momentum transfers. In a continuous diffusion model, this width corresponds to a rotational diffusion constant of 0.277 rad2/ps, a value which is about 3.5 times larger than one extracted from a molecular dynamics simulation of n-butane in the plastic phase recently published by Refson and Pawley [Mol. Phys. 61, 669 (1987); 61, 693 (1987)]. On the other hand, the first process, which corresponds to the carbon-carbon reorientation peak, is about 16 meV wide, indicating that this reorientation occurs on a time scale of about 0.1 ps. The absence of this broad peak in the solid butane at 90 K indicates that this fast carbon-carbon reorientation is coupled to an aspect of the structure or dynamics of the plastic phase. In the scattering from liquid butane at 190 K, there is a third, narrow quasielastic peak which also has a Lorentzian energy distribution. This peak width is about 200-mu-eV and corresponds to a translational diffusion constant of 0.23 angstrom 2/ps, a result in rough agreement with a recent molecular dynamics simulation of liquid butane by Ullo and Yip. [J. Chem. Phys. 85, 4056 (1986)]. C1 MIT,CTR MAT SCI & ENGN,CAMBRIDGE,MA 02139. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545. RP BRADLEY, KF (reprint author), MIT,DEPT NUCL ENGN,CAMBRIDGE,MA 02139, USA. NR 20 TC 6 Z9 6 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1991 VL 95 IS 7 BP 5273 EP 5280 DI 10.1063/1.461666 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600060 ER PT J AU MILLS, RL OLINGER, B CROMER, DT LESAR, R AF MILLS, RL OLINGER, B CROMER, DT LESAR, R TI CRYSTAL-STRUCTURES OF N2O TO 12 GPA BY X-RAY-DIFFRACTION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HIGH-PRESSURE; SOLID CO2; RAMAN-SPECTRA; PHASE; ACETYLENE; TEMPERATURE; COMPRESSION; OXIDE AB The structures and phase transitions of N2O were studied by powder x-ray diffraction in a tungsten-carbide anvil device from about 100 to 300 K and 2 to 12 GPa. Two solid phases, alpha-N2O and beta-N2O, were observed. The alpha-pattern is consistent with the known low-pressure low-temperature ordered cubic form, space group Pa3, up to 4.8 GPa where transition to a new beta-solid occurs. From refinements using photographic x-ray intensities, the beta-N2O structure was determined to be orthorhombic Cmca. There are four molecules in a unit cell with a = 4.954 angstrom, b = 4.497 angstrom, and c = 6.201 angstrom at 5.81 GPa and 298 K. The molecular axes lie parallel to the bc plane and are tipped at an angle of 37.2-degrees to the b axis. Random head-to-tail orientation is probable in both solids. The phase diagram and values of the molar volume for N2O are compared with published data for the isoelectronic molecule CO2. Recent theoretical calculations correctly predict the beta-N2O structure. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RI LeSar, Richard/G-1609-2012 NR 48 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 OCT 1 PY 1991 VL 95 IS 7 BP 5392 EP 5398 DI 10.1063/1.461655 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA GH356 UT WOS:A1991GH35600076 ER PT J AU BARNETT, RN REYNOLDS, PJ LESTER, WA AF BARNETT, RN REYNOLDS, PJ LESTER, WA TI MONTE-CARLO ALGORITHMS FOR EXPECTATION VALUES OF COORDINATE OPERATORS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID RANDOM-WALK; QUANTUM-CHEMISTRY; GREEN-FUNCTION; MOLECULES; ENERGY; SIMULATION; SYSTEMS C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP BARNETT, RN (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 28 TC 89 Z9 89 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD OCT PY 1991 VL 96 IS 2 BP 258 EP 276 DI 10.1016/0021-9991(91)90236-E PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA GH413 UT WOS:A1991GH41300002 ER PT J AU DIPESO, G MORSE, EC ZIOLKOWSKI, RW AF DIPESO, G MORSE, EC ZIOLKOWSKI, RW TI DELTA-F AND PARTICLE SIMULATIONS OF PARAMETRIC-INSTABILITIES SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID COMPACT TOROIDAL PLASMAS; LOWER-HYBRID FREQUENCY; MEDIA C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP DIPESO, G (reprint author), UNIV CALIF BERKELEY,DEPT NUCL ENGN,BERKELEY,CA 94720, USA. NR 13 TC 9 Z9 9 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 OCT PY 1991 VL 96 IS 2 BP 325 EP 338 DI 10.1016/0021-9991(91)90239-H PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA GH413 UT WOS:A1991GH41300005 ER PT J AU SULSKY, D BRACKBILL, JU AF SULSKY, D BRACKBILL, JU TI A NUMERICAL-METHOD FOR SUSPENSION FLOW SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID DYNAMIC SIMULATION; HYDRODYNAMIC INTERACTIONS; CONCENTRATED SUSPENSIONS; STOKES EQUATIONS; PARTICLES; SPHERES; SHEAR C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP SULSKY, D (reprint author), UNIV NEW MEXICO,DEPT MATH & STAT,ALBUQUERQUE,NM 87131, USA. NR 25 TC 80 Z9 80 U1 0 U2 8 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 OCT PY 1991 VL 96 IS 2 BP 339 EP 368 DI 10.1016/0021-9991(91)90240-L PG 30 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA GH413 UT WOS:A1991GH41300006 ER PT J AU CARAMANA, EJ AF CARAMANA, EJ TI DERIVATION OF IMPLICIT DIFFERENCE-SCHEMES BY THE METHOD OF DIFFERENTIAL APPROXIMATION SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Note RP CARAMANA, EJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP X-1,MS-F645,LOS ALAMOS,NM 87545, USA. NR 10 TC 21 Z9 21 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD OCT PY 1991 VL 96 IS 2 BP 484 EP 493 DI 10.1016/0021-9991(91)90248-J PG 10 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA GH413 UT WOS:A1991GH41300014 ER PT J AU SPECHT, ED CLAUSING, RE HEATHERLY, L AF SPECHT, ED CLAUSING, RE HEATHERLY, L TI X-RAY AND OPTICAL CHARACTERIZATION OF 3 GROWTH MORPHOLOGIES OF CVD DIAMOND FILMS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; TEXTURE FORMATION; LOW-PRESSURE; THIN-FILMS AB Using X-ray texture measurements and optical goniometry, we have determined the texture and facet orientation of diamond films grown by CVD with three distinct morphologies. The first morphology has {111} and {100} facets and a <110> texture which is attributed to preferential growth as the result of rapid nucleation of atomic layers at {111} twin boundaries. The second morphology has {100} facets and a <1730> texture which may be due to the influence of surface diffusion on growth competition. The third morphology has {111} facets and a <100> texture which is attributed to competition of uniformly growing grains. RP SPECHT, ED (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. RI Specht, Eliot/A-5654-2009 OI Specht, Eliot/0000-0002-3191-2163 NR 25 TC 11 Z9 11 U1 0 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 OCT PY 1991 VL 114 IS 1-2 BP 38 EP 46 DI 10.1016/0022-0248(91)90676-V PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA GN528 UT WOS:A1991GN52800007 ER PT J AU BKOUCHEWAKSMAN, I KVICK, A BOILLOT, ML KAHN, O AF BKOUCHEWAKSMAN, I KVICK, A BOILLOT, ML KAHN, O TI CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF BIS(2,2'-BIPYRIDINE) AZIDO COPPER(II) PERCHLORATE SO JOURNAL OF CRYSTALLOGRAPHIC AND SPECTROSCOPIC RESEARCH LA English DT Article ID ELECTRONIC-PROPERTIES; COMPLEXES AB The title compound has been synthesized and its crystal structure has been solved at room temperature. It crystallizes in the triclinic system, space group PIBAR, with a = 7.853(1) angstrom, b = 10.177(1) angstrom, c = 13.651(4) angstrom, alpha = 74.57(1)-degrees, beta = 88.49(1)-degrees, gamma = 80.675(4)-degrees, and Z = 2. The structure consists of isolated [Cu(bipy)2N3]+ cations (bipy = 2,2'-bipyridine) and perchlorate anions. The metallic cation environment has a distorted trigonal-bipyramidal geometry. The EPR spectrum is rhombic, which indicates that the distortion with respect to the perfect trigonal bipyramid is sufficiently pronounced to mix z2- and x2-y2-type orbitals in the ground state. The temperature dependence of the molar magnetic susceptibility has been investigated in the 300-2.2 K temperature range. C1 UNIV PARIS 11,CHIM ORGAN LAB,URA 420,F-91405 ORSAY,FRANCE. RP BKOUCHEWAKSMAN, I (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0277-8068 J9 J CRYST SPECTROSC PD OCT PY 1991 VL 21 IS 5 BP 595 EP 600 DI 10.1007/BF01161082 PG 6 WC Crystallography; Spectroscopy SC Crystallography; Spectroscopy GA GJ233 UT WOS:A1991GJ23300009 ER PT J AU MITCHELL, TE UNAL, O AF MITCHELL, TE UNAL, O TI DISLOCATION ARRANGEMENTS IN GAAS/GA1-XINXAS MULTILAYERS GROWN ON (001) SUBSTRATES, (111) SUBSTRATES AND (112) SUBSTRATES SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP AT THE 1991 ANNUAL MEETING OF THE MINERALS, METALS AND MATERIALS SOC : STRAIN RELAXATION IN EPITAXIAL FILMS CY 1991 CL NEW ORLEANS, LA SP MINERALS MET & MAT SOC DE DISLOCATIONS; MULTILAYERS; TEM ID STRAINED-LAYER SUPERLATTICES; MOLECULAR-BEAM-EPITAXY; MISFIT DISLOCATIONS; MECHANICAL-PROPERTIES; CRITICAL THICKNESS; HETEROSTRUCTURES; RELAXATION; DEFECTS; GAAS; GENERATION AB GaAs/Ga1-xInxAs strained layer superlattices with well-widths of 7 nm, barrier widths of 14 nm and periods of 10 to 30 have been examined by transmission electron microscopy in plan view and in cross-section for (001), (111) and (112) substrates. Individual layers are below the critical thickness while the overall SLS's are above the critical thickness for dislocation generation. (001) substrates give rise to square grids of 60-degrees dislocations lying parallel to [110] directions with inclined 1/2 [101] Burgers vectors, resulting from dislocation motion on 8 slip systems. (111) substrates give triangular networks of 60-degrees dislocations lying parallel to [110BAR] directions resulting from motion on 6 slip systems. (112) substrates have two sets of primary dislocations lying along [132BAR] directions, along with secondary 60-degrees dislocations lying along [110BAR]. Long Lomer-Cottrell dislocations with Burgers vectors lying parallel to the substrate/SLS interface are occasionally observed for (001) substrates, while short segments are observed for (112) substrates; these are formed by reaction between conjugate dislocations. These dislocations arrangements are discussed in terms of the resolved shear stresses resulting from epitaxy for the various substrates orientations. Dislocation densities are much less than those required for complete strain relief. This is analyzed in terms of the reduction in the stress acting on dislocations from partial strain relief, along with a friction stress due to a combination of the Peierls stress and solution hardening from the In substitution. A friction stress approximately 10(-3)-mu is required to explain the observed dislocation densities (mu is the shear modulus). RP MITCHELL, TE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 42 TC 31 Z9 31 U1 1 U2 10 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD OCT PY 1991 VL 20 IS 10 BP 723 EP 734 DI 10.1007/BF02665958 PG 12 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA GH657 UT WOS:A1991GH65700005 ER PT J AU KERSTEIN, AR AF KERSTEIN, AR TI LINEAR-EDDY MODELING OF TURBULENT TRANSPORT .6. MICROSTRUCTURE OF DIFFUSIVE SCALAR MIXING FIELDS SO JOURNAL OF FLUID MECHANICS LA English DT Article ID DIRECT NUMERICAL SIMULATIONS; INTERMITTENT TURBULENCE; PASSIVE SCALARS; HOMOGENEOUS TURBULENCE; MOLECULAR-DIFFUSION; FRACTAL DIMENSIONS; STOCHASTIC-MODEL; SHEAR-LAYER; FLOWS; FLUCTUATIONS AB The linear-eddy approach for modelling molecular mixing in turbulent flow involves stochastic simulation on a one-dimensional domain with sufficient resolution to include all physically relevant lengthscales. In each realization, molecular diffusion is implemented deterministically, punctuated by a sequence of instantaneous, statistically independent 'rearrangement events' (measure-preserving maps) representing turbulent stirring. These events emulate the effect of compressive strain on the scalar field. An inertial-range similarity law is incorporated. The model reproduces key features of scalar power spectra, including dependences of spectral amplitudes and transition wavenumbers on Reynolds and Schmidt numbers. Computed scaling exponents governing scalar power spectra, higher-order fluctuation statistics such as structure functions, and the spatial distribution of scalar level crossings are close to measured exponents. It is inferred that the characterization of stirring as a sequence of independent events (the model analogue of eddies) leads to a useful representation of mixing-field microstructure. RP KERSTEIN, AR (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 67 TC 140 Z9 143 U1 1 U2 10 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD OCT PY 1991 VL 231 BP 361 EP 394 DI 10.1017/S0022112091003439 PG 34 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GM800 UT WOS:A1991GM80000015 ER PT J AU AKIMOTO, K WINSKE, D ONSAGER, TG THOMSEN, MF GARY, SP AF AKIMOTO, K WINSKE, D ONSAGER, TG THOMSEN, MF GARY, SP TI STEEPENING OF PARALLEL PROPAGATING HYDROMAGNETIC-WAVES INTO MAGNETIC PULSATIONS - A SIMULATION STUDY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ION-BEAM INSTABILITIES; POLARIZED ALFVEN WAVES; EARTHS BOW SHOCK; WHISTLER WAVES; SOLAR-WIND; UPSTREAM; GENERATION; POPULATIONS; REFLECTION; EXCITATION AB The steepening mechanism of parallel propagating low-frequency MHD-like waves observed up-stream of the Earth's quasi-parallel bow shock has been investigated by means of electromagnetic hybrid simulations. It is shown that an ion beam through the resonant electromagnetic ion/ion instability excites large-amplitude waves, which consequently pitch angle scatter, decelerate, and eventually magnetically trap beam ions in regions where the wave amplitudes are largest. As a result, the beam ions become bunched in both space and gyrophase. As these higher-density, nongyrotropic beam segments are formed, the hydromagnetic waves rapidly steepen, resulting in magnetic pulsations, with properties generally in agreement with observations. This steepening process operates on the scale of the linear growth time of the resonant ion/ion instability. Many of the pulsations generated by this mechanism are left-hand polarized in the spacecraft frame. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP AKIMOTO, K (reprint author), TEIKYO UNIV,SCH SCI & TECHNOL,TOYOSATA DAI 1-1,UTSUNOMIYA 320,JAPAN. NR 39 TC 34 Z9 34 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD OCT 1 PY 1991 VL 96 IS A10 BP 17599 EP 17607 DI 10.1029/91JA01603 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GJ371 UT WOS:A1991GJ37100004 ER PT J AU SPELT, PF KNEE, HE GLOVER, CW AF SPELT, PF KNEE, HE GLOVER, CW TI HYBRID ARTIFICIAL-INTELLIGENCE ARCHITECTURE FOR DIAGNOSIS AND DECISION-MAKING IN MANUFACTURING SO JOURNAL OF INTELLIGENT MANUFACTURING LA English DT Article DE AI; NEURAL NETWORKS; EXPERT SYSTEM; PROCESS CONTROL AB This paper presents an architecture which combines artificial neural networks (ANNs) and an expert system (ES) into a hybrid, self-improving artificial intelligence (AI) system. The purpose of this project is to explore methods of combining multiple AI technologies into a hybrid intelligent diagnostic and advisory system. ANNs and ESs have different strengths and weaknesses, which can be exploited in such a way that they are complementary to each other: strengths in one system make up for weaknesses in the other, and vice versa. There is, presently, considerable interest in ways to exploit the strengths of these methodologies to produce an intelligent system which is more robust and flexible than one using either technology alone. Any process which involves both data-driven (bottom-up) and concept-driven (top-down) processing is especially well suited to displaying the capabilities of such a hybrid system. The system can take an incoming pattern of signals, as from various points in an automated manufacturing process, and make intelligent process control decisions on the basis of the pattern as preprocessed by the ANNs, with rule-based heuristic help or corroboration from the ES. Patterns of data from the environment which can be classified by either the ES or a human consultant can result in a high-level ANN being created and trained to recognize that pattern on future occurrences. In subsequent cases in which the ANN and the ES fail to agree on a decision concerning the environmental situation, the system can resolve those differences and retrain the networks and/or modify the models of the environment stored in the ES. Work on a hybrid system for perception in machine vision has been funded initially by an Oak Ridge National Laboratory seed grant, and most of the system components are operating presently in a parallel distributed computer environment. C1 OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,OAK RIDGE,TN 37831. NR 17 TC 6 Z9 6 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0956-5515 J9 J INTELL MANUF JI J. Intell. Manuf. PD OCT PY 1991 VL 2 IS 5 BP 261 EP 268 DI 10.1007/BF01471174 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Manufacturing SC Computer Science; Engineering GA GK250 UT WOS:A1991GK25000002 ER PT J AU FOLKERTS, TJ KRAMER, MJ DENNIS, KW MCCALLUM, RW AF FOLKERTS, TJ KRAMER, MJ DENNIS, KW MCCALLUM, RW TI MELT-SPIN PROCESSING OF YBA2CU3O7-X SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID TRANSPORT; ANISOTROPY AB We introduce a novel containerless melt-spin processing technique for YBa2Cu3O7-x using prereacted oxide powders that are rapidly melted and subsequentially quenched in a controlled atmosphere. This results in flakes with typical dimensions of 3000 x 150 x 15-mu-m3. Powder XRD indicates that all samples contain Y2O3, but that the Ba-Cu-O phases present depend on the processing parameters. SEM and TEM studies show these phases are finely dispersed: the typical grain size for Y2O3 is 1-2-mu-m, and for the Ba-Cu-O phases it is < 0.5-mu-m. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT GEOL & ATMOSPHER SCI,AMES,IA 50010. IOWA STATE UNIV SCI & TECHNOL,INST PHYS RES & TECHNOL,AMES,IA 50010. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50010. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50010. RP FOLKERTS, TJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,INST PHYS RES & TECHNOL,AMES,IA 50010, USA. NR 10 TC 12 Z9 12 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD OCT PY 1991 VL 6 IS 10 BP 2035 EP 2040 DI 10.1557/JMR.1991.2035 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA GJ509 UT WOS:A1991GJ50900004 ER PT J AU MCHARGUE, CJ SKLAD, PS WHITE, CW FARLOW, GC PEREZ, A MAREST, G AF MCHARGUE, CJ SKLAD, PS WHITE, CW FARLOW, GC PEREZ, A MAREST, G TI MICROSTRUCTURAL AND CHEMICAL EFFECTS IN AL2O3 IMPLANTED WITH IRON AT ROOM-TEMPERATURE AND ANNEALED IN OXIDIZING OR REDUCING ATMOSPHERES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ION IMPLANTATION; ALPHA-AL2O3; MOSSBAUER; CRYSTALS AB Rutherford backscattering (RBS)-ion channeling, transmission electron microscopy (TEM), and conversion electron Mossbauer spectroscopy (CEMS) have been used to determine the structure of alpha-Al2O3 implanted with iron at room temperature. Changes produced by post-implantation annealing in oxidizing and reducing atmospheres were followed using the same techniques. Implantation of 160 keV Fe at room temperature produces a damaged but crystalline microstructure for fluences as high as 1 x 10(17) Fe/cm2. The iron resides in a variety of local environments: three Fe2+ components, one Fe0 component, and two Fe4+ components. The relative amount of each component varies with implantation fluence. Only the Fe0 component seems to be associated with second-phase formation. In this case, 2 nm diameter alpha-iron particles were detected by TEM studies. Recovery of implantation-induced disorder in the Al- and oxygen-sublattices occurs in two stages for annealing in oxygen and in one continuous stage for hydrogen-annealing. The end state for iron is Fe3+ for oxygen anneals and Fe0 for hydrogen anneals. The precipitated phases observed are those to be expected from the equilibrium phase diagrams. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV LYON 1,DEPT PHYS MAT,F-69622 VILLEURBANNE,FRANCE. UNIV LYON 1,INST PHYS NUCL LYON,CNRS,INST NATL PHYS NUCL & PHYS PARTICLES,F-69622 VILLEURBANNE,FRANCE. NR 22 TC 63 Z9 65 U1 1 U2 3 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD OCT PY 1991 VL 6 IS 10 BP 2145 EP 2159 DI 10.1557/JMR.1991.2145 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA GJ509 UT WOS:A1991GJ50900018 ER PT J AU MCHARGUE, CJ SKLAD, PS WHITE, CW MCCALLUM, JC PEREZ, A MAREST, G AF MCHARGUE, CJ SKLAD, PS WHITE, CW MCCALLUM, JC PEREZ, A MAREST, G TI MICROSTRUCTURAL AND CHEMICAL EFFECTS IN AL2O3 IMPLANTED WITH IRON AT 77-K AND ANNEALED IN OXIDIZING OR REDUCING ATMOSPHERES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID OXIDES AB Implantation of Fe (160 keV) into alpha-Al2O3 at 77 K produces an amorphous surface layer for fluences in the range of 10(16) to 10(17) Fe/cm2. Measurements of short-range order were made by extended energy loss fine structure analysis (EXELFS). The structure of amorphous Al2O3 produced by implantation of iron at 77 K exhibits short-range order that differs from that produced by stoichiometric (Al + O) implants. This difference is manifested by changes in the Al-O near-neighbor bond length. The local environments of implanted iron were determined from conversion electron Mossbauer spectroscopy (CEMS). The iron resides in several different local environments consistent with the electronic states of Fe2+, Fe4+, and Fe0. The relative amount of each environment depends upon the concentration (fluence) of the implanted iron ions. Regrowth of the amorphous zone during annealing occurs in the sequence amorphous --> gamma-Al2O3 --> alpha-Al2O3. The kinetics of regrowth and phase separation vary with implanted fluence and with annealing atmosphere. The higher the concentration of implanted iron, the slower the formation of iron-aluminum oxide precipitate phases in oxidizing atmospheres and alpha-Fe precipitates in reducing atmospheres. C1 UNIV LYON 1,DEPT PHYS MAT,F-69622 VILLEURBANNE,FRANCE. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV LYON 1,INST PHYS NUCL LYON,CNRS,INST NATL PHYS NUCL & PHYS PARTICLES,F-69622 VILLEURBANNE,FRANCE. NR 11 TC 20 Z9 20 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD OCT PY 1991 VL 6 IS 10 BP 2160 EP 2177 DI 10.1557/JMR.1991.2160 PG 18 WC Materials Science, Multidisciplinary SC Materials Science GA GJ509 UT WOS:A1991GJ50900019 ER PT J AU YOUNGMAN, RA MITCHELL, TE CLINARD, FW HURLEY, GF AF YOUNGMAN, RA MITCHELL, TE CLINARD, FW HURLEY, GF TI HIGH-DOSE NEUTRON-IRRADIATION DAMAGE IN ALPHA ALUMINA SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AL2O3; MICROSTRUCTURE; MOLYBDENUM; IONS AB Bulk samples of single crystalline and polycrystalline alpha alumina have been neutron-irradiated in the Experimental Breeder Reactor-II (EBR-II) to doses of 10(26) n/m2 at temperatures of 925 K and 1100 K. The samples were found to swell macroscopically between 3% and 6%, depending on the temperature of irradiation and the form of the material. The damaged microstructures were investigated via transmission electron microscopy in order to understand the origin of the macroscopic swelling. In both single crystals and polycrystals the damage consists of a high density of dislocations containing predominately b = 1/3<1011BAR> dislocation loops on the (0001) planes coexistent with a high density of voids, which are aligned along the c-axis in this rhombohedral material. The established theory of void formation in metals is utilized to explain the formation of voids in alumina. The polycrystalline samples were extensively microcracked, and this is thought to be due to anisotropic swelling of the grains which in turn leads to stresses and fracturing at the grain boundaries. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP YOUNGMAN, RA (reprint author), BP RES,4440 WARRENSVILLE CTR RD,CLEVELAND,OH 44128, USA. NR 35 TC 26 Z9 26 U1 1 U2 7 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD OCT PY 1991 VL 6 IS 10 BP 2178 EP 2187 DI 10.1557/JMR.1991.2178 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA GJ509 UT WOS:A1991GJ50900020 ER PT J AU HSUEH, CH BECHER, PF AF HSUEH, CH BECHER, PF TI THERMAL-STRESSES DUE TO THERMAL-EXPANSION ANISOTROPY IN MATERIALS WITH PREFERRED ORIENTATION SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID RESIDUAL-STRESSES; STRAIN RP HSUEH, CH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 10 TC 8 Z9 10 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD OCT 1 PY 1991 VL 10 IS 19 BP 1165 EP 1167 DI 10.1007/BF00744115 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA GH991 UT WOS:A1991GH99100023 ER PT J AU EVANS, JW KANG, HC AF EVANS, JW KANG, HC TI ANALYTIC OBSERVATIONS FOR THE D = 1 + 1 BRIDGE SITE (OR SINGLE-STEP) DEPOSITION MODEL SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID INTERFACE GROWTH; LATTICE; MODELS; DEPOSITION; DIFFUSION; PARTICLES; SURFACES; EQUATION AB Some exact results for a reversible version of the d = 1 + 1 bridge site (or single-step) deposition model are presented. Exact steady-state properties are determined directly for finite systems with various mean slopes. These show explicitly how the asymptotic growth velocity and fluctuations are quenched as the slope approaches its maximum allowed value. Next, exact hierarchial equations for the dynamics are presented. For the special case of "equilibrium growth," these are analyzed exactly at the pair-correlation level directly for an infinite system. This provided further insight into asymptotic scaling behavior. Finally, the above hierarchy is compared with one generated from a discrete form of the Kardar-Parisi-Zhang equations. Some differences are described. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP EVANS, JW (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT MATH,AMES,IA 50011, USA. RI Kang, Hway Chuan/A-3401-2012 NR 19 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD OCT PY 1991 VL 32 IS 10 BP 2918 EP 2922 DI 10.1063/1.529085 PG 5 WC Physics, Mathematical SC Physics GA GJ154 UT WOS:A1991GJ15400039 ER PT J AU WEBER, DA CABAHUG, C KLIEGER, P VOLKOW, ND WONG, C SACKER, D IVANOVIC, M AF WEBER, DA CABAHUG, C KLIEGER, P VOLKOW, ND WONG, C SACKER, D IVANOVIC, M TI EFFECTS OF VISUAL-STIMULATION ON THE REDISTRIBUTION OF IODINE-123-IMP IN THE BRAIN USING SPECT IMAGING SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article ID CEREBRAL BLOOD-FLOW; N-ISOPROPYL-(I-123)PARA-IODOAMPHETAMINE; IODOAMPHETAMINE; TOMOGRAPHY; DYNAMICS; ISCHEMIA; IMP AB A study was performed to validate the assumption that redistribution and clearance of [I-123]IMP localization in the brain are unaffected by changes in ambient light levels and visual stimulation occurring after radiopharmaceutical is administered and deposited in the brain. Serial SPECT and planar imaging studies were performed on six healthy, volunteer, adult male subjects under resting, nonactivation conditions. Studies were repeated 7 days later with each subject exposed to strobe light stimulation prior to delayed SPECT procedures at 3 hr. Redistribution and clearance of I-123-IMP in the brain were examined in cortical, subcortical, and cerebellar regions on transaxial slices for the two sets of serial procedures in each subject. Visual stimulation following the initial uptake of [I-123]IMP did not affect the distribution or clearance of [I-123] IMP in the brain, including the visual cortex, and therefore should not influence the interpretation of delayed SPECT images. RP WEBER, DA (reprint author), BROOKHAVEN NATL LAB,DEPT MED,NUCL MED RES GRP,UPTON,NY 11973, USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 22090-5316 SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD OCT PY 1991 VL 32 IS 10 BP 1866 EP 1872 PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA GH706 UT WOS:A1991GH70600008 PM 1919724 ER PT J AU ROVER, D TSAI, V CHOW, YS GUSTAFSON, J AF ROVER, D TSAI, V CHOW, YS GUSTAFSON, J TI SIGNAL-PROCESSING ALGORITHMS ON PARALLEL ARCHITECTURES - A PERFORMANCE UPDATE SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Note C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,SCALABLE COMP LAB,AMES,IA 50011. NR 14 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD OCT PY 1991 VL 13 IS 2 BP 237 EP 245 DI 10.1016/0743-7315(91)90093-O PG 9 WC Computer Science, Theory & Methods SC Computer Science GA GJ341 UT WOS:A1991GJ34100012 ER PT J AU AHO, JM UGLEM, GL MOORE, JP LARSON, OR AF AHO, JM UGLEM, GL MOORE, JP LARSON, OR TI BACTERIA ASSOCIATED WITH THE TEGUMENT OF CLINOSTOMUM-MARGINATUM (DIGENEA) SO JOURNAL OF PARASITOLOGY LA English DT Note AB Adults of Clinostomum marginatum freshly collected from a heron, Ardea herodias, were examined using transmission electron microscopy. Specimens from the mouth of the bird were encrusted with bacteria that were not removed by washing unless the saline contained antibiotics. There was no evidence that the attached bacteria were damaging to the trematode tegument. Three species of Gram-negative bacteria were isolated from the worm surfaces and identified; Achromobacter sp. was present in pure culture on 4 of 6 original cultures and in mixed culture with Edwardsiella tarda and Enterobacter agglomerans in 2 cultures. These species and 3 unidentified species of bacteria were isolated from the oral epithelium of the heron. Microorganisms were not seen attached to the surfaces of worms recovered from the esophagus. Because E. tarda and E. agglomerans were the only species isolated from the heron esophagus, the intimate bacterial-worm association in the heron mouth may be due specifically to Achromobacter sp. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. UNIV KENTUCKY,SCH BIOL SCI,LEXINGTON,KY 40506. UNIV N DAKOTA,DEPT BIOL,GRAND FORKS,ND 58202. NR 9 TC 11 Z9 12 U1 0 U2 2 PU AMER SOC PARASITOLOGISTS PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 SN 0022-3395 J9 J PARASITOL JI J. Parasitol. PD OCT PY 1991 VL 77 IS 5 BP 784 EP 786 DI 10.2307/3282717 PG 3 WC Parasitology SC Parasitology GA GL342 UT WOS:A1991GL34200024 PM 1919930 ER PT J AU FROST, BRT AF FROST, BRT TI THE COMMERCIALIZATION OF NATIONALLY FUNDED RESEARCH-AND-DEVELOPMENT SO JOURNAL OF SCIENTIFIC & INDUSTRIAL RESEARCH LA English DT Article AB US policy on R&D and technology transfer is outlined. It is pointed out that to remain competitive with the rest of the world, the United States is attempting to utilize the resources of its national laboratories. A succession of federal laws has made this process more effective, particularly with respect to the ownership and licensing of intellectual property generated by the laboratories. Examples of Argonne National Laboratory, located near Chicago and operated for the Department of Energy by the University of Chicago, has been cited to show how inventions arising from federally-funded research are commercialized. Argonne and the University created ARCH, a not-for-profit corporation, to handle their intellectual property. Since 1987 ARCH has licensed 32 Argonne inventions to industry and has created three companies based on Argonne inventions, plus four based on University inventions. The income from these activities is used to reward the inventors, pay for operating costs of ARCH and to fund the further development of concepts towards commercialization. It is pointed out that other mechanisms are needed to bring industry and national labs closer together: these include affiliates programs, consortia, co-operative research agreements, sponsored research, staff exchanges and access to major experimental facilities, such as accelerators and electron microscopes. National laboratories can have a significant influence on the economy of the region in which they are located. A state-funded Technology Commercialization Center to assist local companies was established at Argonne in 1985; assistance takes the form of grants and access to technical expertise and facilities. A number of the lessons learned from the experience at Argonne in the period 1985-1990 may have application to developing countries. RP FROST, BRT (reprint author), ARGONNE NATL LAB,CTR TECHNOL TRANSFER,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 1 Z9 1 U1 0 U2 1 PU COUNCIL SCIENTIFIC INDUSTRIAL RESEARCH PI NEW DELHI PA PUBL & INFO DIRECTORATE, NEW DELHI 110012, INDIA SN 0022-4456 J9 J SCI IND RES INDIA JI J. Sci. Ind. Res. PD OCT PY 1991 VL 50 IS 10 BP 753 EP 759 PG 7 WC Engineering, Multidisciplinary SC Engineering GA GN913 UT WOS:A1991GN91300006 ER PT J AU SULLIVAN, JD BUTTREY, DJ COX, DE HRILJAC, J AF SULLIVAN, JD BUTTREY, DJ COX, DE HRILJAC, J TI A CONVENTIONAL AND HIGH-RESOLUTION SYNCHROTRON X-RAY-DIFFRACTION STUDY OF PHASE SEPARATIONS IN PR2NIO4+DELTA SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID NONSTOICHIOMETRY; ND2NIO4 C1 BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RP SULLIVAN, JD (reprint author), UNIV DELAWARE, DEPT CHEM ENGN, NEWARK, DE 19716 USA. NR 17 TC 26 Z9 26 U1 1 U2 13 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 EI 1095-726X J9 J SOLID STATE CHEM JI J. Solid State Chem. PD OCT PY 1991 VL 94 IS 2 BP 337 EP 351 DI 10.1016/0022-4596(91)90200-2 PG 15 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA GH702 UT WOS:A1991GH70200016 ER PT J AU SCHULTZ, AJ BENO, MA GEISER, U WANG, HH KINI, AM WILLIAMS, JM WHANGBO, MH AF SCHULTZ, AJ BENO, MA GEISER, U WANG, HH KINI, AM WILLIAMS, JM WHANGBO, MH TI SINGLE-CRYSTAL X-RAY AND NEUTRON-DIFFRACTION INVESTIGATIONS OF THE TEMPERATURE-DEPENDENCE OF THE STRUCTURE OF THE TC = 10-K ORGANIC SUPERCONDUCTOR KAPPA-(ET)2CU(NCS)2 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID AMBIENT PRESSURE; (BEDT-TTF)2CU(NCS)2; SALTS C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. RP SCHULTZ, AJ (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Kini, Aravinda/F-4467-2012 NR 16 TC 31 Z9 31 U1 0 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD OCT PY 1991 VL 94 IS 2 BP 352 EP 361 DI 10.1016/0022-4596(91)90201-R PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA GH702 UT WOS:A1991GH70200017 ER PT J AU RUNDLE, JB BROWN, SR AF RUNDLE, JB BROWN, SR TI ORIGIN OF RATE DEPENDENCE IN FRICTIONAL SLIDING SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE FRICTION; CRITICAL PHENOMENA; EARTHQUAKES; SELF-ORGANIZED CRITICALITY; SCALING ID SLIP AB Experiments indicate that frictional resistance to sliding between macroscopic, clean, dry surfaces depends on the average rate V at which the surfaces are translated relative to each other. Using a new lattice automaton, we obtain results suggesting that rate-dependent macroscopic dynamics may arise from microscopic interactions between contact points which decay from a metastable state with a finite lifetime-GAMMA. Sliding is accommodated by clusters, or avalanches, of failed lattice contact points, and corresponds to successive quenches into the metastable state by an electromechanical loading system with a finite response time-DELTA. Under the quasistatic assumption DELTA >> GAMMA, rate dependence is a consequence of the increase in correlation length zeta-d of clusters of failed lattice points as quench rate increases. Special cases of the model are isomorphic to the self-organized criticality model for sandpiles, and to block-spring models of the type first studied by Burridge and Knopoff for earthquakes. C1 SANDIA NATL LABS,DEPT EARTH & ENVIRONM DYNAM 6230,ALBUQUERQUE,NM 87185. RP RUNDLE, JB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT EARTH SCI,L-202,LIVERMORE,CA 94550, USA. NR 16 TC 38 Z9 38 U1 1 U2 5 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 OCT PY 1991 VL 65 IS 1-2 BP 403 EP 412 DI 10.1007/BF01329869 PG 10 WC Physics, Mathematical SC Physics GA GM637 UT WOS:A1991GM63700022 ER PT J AU STILLER, L AF STILLER, L TI GROUP GRAPHS AND COMPUTATIONAL SYMMETRY ON MASSIVELY PARALLEL ARCHITECTURE SO JOURNAL OF SUPERCOMPUTING LA English DT Article DE SYMMETRY; GROUP ACTION GRAPHS; CAYLEY GRAPHS; INTERCONNECTION NETWORKS; CHESS ENDGAMES; DISTRIBUTED MEMORY AB Efficient space and time exploitation of symmetry in domains on highly parallel, distributed-memory architecture is, in certain cases, equivalent to routing along a labeled group action graph, with computation associated with each group element label, where the group of symmetries acts on the processors. The algebraic structure of the group can sometimes be analyzed to determine, a priori, space and time efficient routing schedules on the hardware network (which, in practice, is often another group action graph). The algorithms we develop were implemented on a 64K-processor CM-2 and used to solve certain natural classes of chess endgames, part of whose search space is invariant under a noncommutative crystallographic group. This program runs 400 times faster than any previous implementation, and discovered many interesting new results in the area; some of these results are not solvable in practice with current serial techniques because the time and space requirements are too large. It seems interesting that it was possible, albeit with difficulty, to implement efficiently certain irregular chess rules on the CM-2, which is optimized for regular data sets. C1 JOHNS HOPKINS UNIV,DEPT COMP SCI,BALTIMORE,MD 21218. RP STILLER, L (reprint author), LOS ALAMOS NATL LAB,MS B284,LOS ALAMOS,NM 87545, USA. NR 12 TC 13 Z9 13 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-8542 J9 J SUPERCOMPUT JI J. Supercomput. PD OCT PY 1991 VL 5 IS 2-3 BP 99 EP 117 DI 10.1007/BF00127839 PG 19 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GQ593 UT WOS:A1991GQ59300001 ER PT J AU CLEM, JR AF CLEM, JR TI THE BARDEEN-STEPHEN THEORY SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE BARDEEN-STEPHEN THEORY; VORTEX DYNAMICS AB The experimental situation that prompted the theory is reviewed, the essentials of the Bardeen-Stephen theory are sketched, and several extensions are mentioned, particularly those that are needed to understand the high-temperature copper-oxide superconductors. RP CLEM, JR (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 0 TC 1 Z9 1 U1 0 U2 3 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 1991 VL 4 IS 5 BP 337 EP 339 DI 10.1007/BF00618214 PG 3 WC Physics, Applied; Physics, Condensed Matter SC Physics GA GT524 UT WOS:A1991GT52400006 ER PT J AU STRONGIN, M AF STRONGIN, M TI THE SEARCH FOR AN EXCITONIC MECHANISM - A RECOLLECTION OF BARDEEN,JOHN SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE EXCITONIC MECHANISM; SUPERCONDUCTIVITY; BARDEEN,JOHN RP STRONGIN, M (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, 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 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 1991 VL 4 IS 5 BP 357 EP 360 DI 10.1007/BF00618216 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA GT524 UT WOS:A1991GT52400008 ER PT J AU VISSCHER, WM MIGLIORI, A BELL, TM REINERT, RA AF VISSCHER, WM MIGLIORI, A BELL, TM REINERT, RA TI ON THE NORMAL-MODES OF FREE-VIBRATION OF INHOMOGENEOUS AND ANISOTROPIC ELASTIC OBJECTS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID RESONANCE METHOD; CONSTANTS; CRYSTALS AB The Hamilton's principle approach to the calculation of vibrational modes of elastic objects with free boundaries is exploited to compute the resonance frequencies of a variety of anisotropic elastic objects, including spheres, hemispheres, spheroids, ellipsoids, cylinders, eggs, shells, bells, sandwiches, parallelepipeds, cones, pyramids, prisms, tetrahedra, octahedra, and potatoes. The paramount feature of this calculation, which distinguishes it from previous ones, is the choice of products of powers of the Cartesian coordinates as a basis for expansion of the displacement in a truncated complete set, enabling one to analytically evaluate the required matrix elements for these systems. Because these basis functions are products of powers of x, y, and z, this scheme is called the xyz algorithm. The xyz algorithm allows a general anisotropic elastic tensor with any position dependence and any shape with arbitrary density variation. A number of plots of resonance spectra of families of elastic objects are displayed as functions of relevant parameters, and, to illustrate the versatility of the method, the measured resonant frequencies of a precision machined but irregularly shaped sample of aluminum (called a potato) are compared with its computed normal modes. Applications to materials science and to seismology are mentioned. RP VISSCHER, WM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 20 TC 198 Z9 199 U1 1 U2 22 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD OCT PY 1991 VL 90 IS 4 BP 2154 EP 2162 DI 10.1121/1.401643 PN 1 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA GJ147 UT WOS:A1991GJ14700046 ER PT J AU PASK, JA TOMSIA, AP AF PASK, JA TOMSIA, AP TI FORMATION OF MULLITE FROM SOL-GEL MIXTURES AND KAOLINITE SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; SPINEL PHASE; REACTION-SERIES; REACTION SEQUENCE; STRUCTURAL CHARACTERIZATION; OUTSTANDING PROBLEMS; LATTICE ENERGY; SI-29; AL-27; TRANSFORMATIONS AB Critical analyses of published reaction studies on kaolinite, and sol-gel and powder mixtures equivalent to 3Al2O3.2SiO2 mullite, were made. Supplementary experiments on reactions of kaolinite at different rates of heating were analyzed. Complete atomic homogeneity of precursors results in formation of tetragonal mullite. Colloidal precursors initially form spinel which reacts with the remaining silica by a diffusion-nucleation mechanism to form orthorhombic mullite. Precursors with intermediate atomic homogeneity follow both reaction paths. Kaolinite with a layer lattice structure has two-dimensional atomic homogeneity. Both reaction routes are followed and their degree of interaction is dependent on the crystallinity and impurities of the kaolinite. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP PASK, JA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 46 TC 101 Z9 102 U1 4 U2 12 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 1991 VL 74 IS 10 BP 2367 EP 2373 DI 10.1111/j.1151-2916.1991.tb06770.x PG 7 WC Materials Science, Ceramics SC Materials Science GA GM652 UT WOS:A1991GM65200004 ER PT J AU FAHRENHOLTZ, WG HIETALA, SL NEWCOMER, P DANDO, NR SMITH, DM BRINKER, CJ AF FAHRENHOLTZ, WG HIETALA, SL NEWCOMER, P DANDO, NR SMITH, DM BRINKER, CJ TI EFFECT OF PHYSICAL STRUCTURE ON THE PHASE DEVELOPMENT OF ALUMINOSILICATE GELS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID RESOLUTION SI-29 NMR; NUCLEAR MAGNETIC-RESONANCE; MAGIC-ANGLE; SURFACE-AREA; MULLITE; ALUMINA; SYSTEM; AL-27; SILICATE AB The surface area and density of aluminosilicate xerogels containing a one-to-one Al/Si molar ratio (47 wt% alumina) can be varied dramatically by changing the pore fluid prior to drying. The surface area of ethanol-washed 47 wt% alumina gels was more than 500 m2/g, while gels dried from the mother liquor (approximately 75 vol% ethanol, 25 vol% water) had less than 1 m2/g surface area. Changes in the physical structure of the dried gels had dramatic effects on subsequent phase evolution and densification behavior during heat treatment. NMR, X-ray diffraction, and DTA were used to follow the phase evolution of different gels. Differences in the amorphous gel structure were identified using Al-27 and Si-29 MAS NMR. Gels of identical composition prepared from the same precursor solutions crystallized to different phases, depending upon the surface area of the gel prior to heating. The high surface material (ethanol washed) formed mullite and amorphous silica, while the low surface area gel (unwashed) crystallized to mullite and cristobalite. These gels were prepared from alkoxide precursors. A low surface area gel with a different degree of chemical homogeneity was prepared by the nitrate method for comparison. Results indicate that the physical structure of aluminosilicate gels, i.e., pore structure and chemical homogeneity, has a dramatic influence on phase evolution. C1 UNIV NEW MEXICO,NSF,CTR MICRO ENGN CERAM,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. ALCOA TECH CTR,ALCOA CTR,PA 15069. NR 27 TC 6 Z9 6 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 OCT PY 1991 VL 74 IS 10 BP 2393 EP 2397 DI 10.1111/j.1151-2916.1991.tb06774.x PG 5 WC Materials Science, Ceramics SC Materials Science GA GM652 UT WOS:A1991GM65200008 ER PT J AU BOREK, TT QIU, XM RAYFUSE, LM DATYE, AK PAINE, RT ALLARD, LF AF BOREK, TT QIU, XM RAYFUSE, LM DATYE, AK PAINE, RT ALLARD, LF TI BORON-NITRIDE COATINGS ON OXIDE SUBSTRATES - ROLE OF SURFACE MODIFICATIONS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SMALL METAL CRYSTALLITES; HETEROGENEOUS CATALYSTS AB Physical mixtures of a BN polymeric precursor with oxides such as MgO, Al2O3, and TiO2 have been found to yield crystalline, tightly adherent coatings of hexagonal BN on the oxide surface, after appropriate heat treatments. In every instance, the BN (0001) basal planes are parallel to the oxide surface. Generally, the coating conforms very well to the contours of the oxide surface. However, an exception was the silica surface where no coatings were observed. It appears that the surface silanols condense to form siloxanes at high temperatures, yielding a surface that is unreactive and unable to bind to the BN. Modification of the silica surface by incorporation of a monolayer of titania dramatically alters the ability of the silica to stabilize BN coatings. It was found that stable BN coatings could be obtained when the silica surfaces were thus modified. C1 UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,CTR MICROENGN CERAM,ALBUQUERQUE,NM 87131. OAK RIDGE NATL LAB,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831. NR 15 TC 23 Z9 23 U1 2 U2 7 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 1991 VL 74 IS 10 BP 2587 EP 2591 DI 10.1111/j.1151-2916.1991.tb06804.x PG 5 WC Materials Science, Ceramics SC Materials Science GA GM652 UT WOS:A1991GM65200038 ER PT J AU BHATTACHARYA, AK PETROVIC, JJ AF BHATTACHARYA, AK PETROVIC, JJ TI HARDNESS AND FRACTURE-TOUGHNESS OF SIC-PARTICLE-REINFORCED MOSI2 COMPOSITES SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CRACK; RESISTANCE; CERAMICS AB The indentation technique has been used to evaluate the hardness and fracture toughness of SiC-reinforced MoSi2 composites made by hot-pressing. It is seen that the toughness increases with increasing indentation crack length (under increasing load) and a probable mechanism responsible for this behavior is described. It is also observed that there is an optimum volume fraction of SiC particles for which the maximum fracture toughness of the composite can be achieved. RP BHATTACHARYA, AK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 18 TC 95 Z9 98 U1 2 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 1991 VL 74 IS 10 BP 2700 EP 2703 DI 10.1111/j.1151-2916.1991.tb06828.x PG 4 WC Materials Science, Ceramics SC Materials Science GA GM652 UT WOS:A1991GM65200062 ER PT J AU DELVILLEDESBOIS, MH BROWN, DS VOLLHARDT, KPC ASTRUC, D AF DELVILLEDESBOIS, MH BROWN, DS VOLLHARDT, KPC ASTRUC, D TI REDOX CHEMISTRY OF THE HETERODINUCLEAR FULVALENE COMPLEXES [WM(FULVALENE)(CO)5], M = FE OR RU - SELECTIVE METAL REDOX RECOGNITION SO JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS LA English DT Article ID REACTIVITY AB The redox chemistry of [WM(fulvalene)(CO)5], M = Fe (1) and Ru (2) allows the specific redox properties of each metal centre to be distinguished. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP DELVILLEDESBOIS, MH (reprint author), UNIV BORDEAUX 1,CHIM ORGAN & ORGANOMET LAB,CNRS,URA 35,351 COURS LIBERAT,F-33405 TALENCE,FRANCE. RI DELVILLE, Marie-Helene/C-6040-2011 OI DELVILLE, Marie-Helene/0000-0001-8863-8225 NR 11 TC 23 Z9 23 U1 0 U2 0 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 OCT 1 PY 1991 IS 19 BP 1355 EP 1357 DI 10.1039/c39910001355 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA GL522 UT WOS:A1991GL52200019 ER PT J AU SILKS, LA PENG, J ODOM, JD DUNLAP, RB AF SILKS, LA PENG, J ODOM, JD DUNLAP, RB TI SYNTHESIS OF (4S,5R)-(-)-4-METHYL-5-PHENYLOXAZOLIDINE-2-SELONE - A CHIRAL AUXILIARY REAGENT CAPABLE OF DETECTING THE ENANTIOMERS OF (R,S)-LIPOIC ACID BY SE-77 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY SO JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 LA English DT Article ID SELENIUM DOUBLE-BONDS; ORGANOSELENIUM COMPOUNDS; ALPHA-CHYMOTRYPSIN; NMR; ISOCYANIDES; C=SE AB (4S,5R)-(-)-4-Methyl-5-phenyloxazolidine-2-selone was constructed in 5 steps on the 10-gram scale. Se-77 NMR spectroscropic studies revealed that this selone served as a remarkably sensitive chiral auxiliary agent which readily distinguished the selone-coupled (R,S)-lipoic acid (DELTA-delta 0.119 ppm), even though its chiral centre was separated by 8 bonds from the observed nucleus. C1 UNIV S CAROLINA,DEPT CHEM,COLUMBIA,SC 29208. RP SILKS, LA (reprint author), NIH,LOS ALAMOS NATL LAB,STABLE ISOTOPES RESOURCE,INC-4,MS C-345,LOS ALAMOS,NM 87545, USA. NR 45 TC 31 Z9 31 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0300-922X J9 J CHEM SOC PERK T 1 JI J. Chem. Soc.-Perkin Trans. 1 PD OCT PY 1991 IS 10 BP 2495 EP 2498 DI 10.1039/p19910002495 PG 4 WC Chemistry, Organic SC Chemistry GA GK057 UT WOS:A1991GK05700030 ER PT J AU ODEGARD, R SKOTHEIM, TA LEE, HS AF ODEGARD, R SKOTHEIM, TA LEE, HS TI AN ELECTROCHEMICAL AND OPTICAL INVESTIGATION OF POLYPYRROLE POLYETHYLENEOXIDE LATEX-PARTICLES SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID FILM; DISPERSIONS; MORPHOLOGY; ELECTRODES; ELECTROPOLYMERIZATION; COMPOSITES; BATTERY; ANIONS; MEDIA AB Submicronic polypyrrole/polyethylene-oxide (PPy/PEO) latex particles have been produced using PEO as the steric stabilizer and either FeCl3 or K2S2O8 as the oxidizing agent for pyrrole. Scanning electron micrographs show that the two types of PPy/PEO latex particles are of approximately the same size. From electrochemical and optical characterization (UV-vis spectra) of these particles, it was found that these latex particles can be electrochemically oxidized and reduced in an electrolyte of acetonitrile with 0.1M LiCF3SO3. The electrochemical and optical measurements indicate that the latex particles formed when using K2S2O8 as the oxidizing agent are more easily switched than the particles which are the result of applying FeCl3 as the oxidizing agent. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV MAT SCI,UPTON,NY 11973. NR 23 TC 36 Z9 36 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 OCT PY 1991 VL 138 IS 10 BP 2930 EP 2934 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA GJ144 UT WOS:A1991GJ14400020 ER PT J AU RIZO, P GRANGEAT, P SIRE, P LEMASSON, P MELENNEC, P AF RIZO, P GRANGEAT, P SIRE, P LEMASSON, P MELENNEC, P TI COMPARISON OF 2 3-DIMENSIONAL X-RAY CONE-BEAM-RECONSTRUCTION ALGORITHMS WITH CIRCULAR SOURCE TRAJECTORIES SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID IMAGE-RECONSTRUCTION; PROJECTIONS; TOMOGRAPHY; CERAMICS; FORMULA AB We compare two algorithms of three-dimensional (3D) cone-beam tomography: a 3D backprojection algorithm and a Radon algorithm, with a circular source trajectory. We recall the principle of these algorithms and show that when the source trajectory is circular, an exact reconstruction cannot be performed. We evaluate structures that cannot be detected and show that, for each algorithm, assumptions must be made about the object to estimate the missing information. Using simulated data, we measured the modulation transfer function of the two algorithms, evaluated the density resolution, and measured the artifacts due to missing information. We show that the 3D backprojection algorithm has good geometrical resolution along the axis of rotation and that, from the standpoint of density resolution, its useful limit is +/- 3-degrees. We also show that it is sensitive to the lack of information in the horizontal planes. The useful aperture of the Radon algorithm is +/- 12-degrees; for apertures lower than this limit, the algorithm is much less sensitive to the lack of information in the horizontal planes than the 3D backprojection algorithm. We present two examples of reconstructions that illustrate the limitations of these algorithms when applied to realistic samples and discuss the limits of using each algorithm when the source trajectory is circular. C1 CEA,DEPT SYST,DIV ELECTR TECHNOL & INSTRUMENTAT,F-38041 GRENOBLE,FRANCE. CEN,F-38041 GRENOBLE,FRANCE. RP RIZO, P (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 28 TC 19 Z9 19 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD OCT PY 1991 VL 8 IS 10 BP 1639 EP 1648 DI 10.1364/JOSAA.8.001639 PG 10 WC Optics SC Optics GA GH718 UT WOS:A1991GH71800015 ER PT J AU NOID, DW VARMANAIR, M WUNDERLICH, B DARSEY, JA AF NOID, DW VARMANAIR, M WUNDERLICH, B DARSEY, JA TI NEURAL NETWORK INVERSION OF THE TARASOV FUNCTION USED FOR THE COMPUTATION OF POLYMER HEAT-CAPACITIES SO JOURNAL OF THERMAL ANALYSIS LA English DT Article ID SKELETAL VIBRATIONS; MACROMOLECULES AB The neural network method is trained using back propagation with a series of heat capacities (C(v)) in the temperature range 10 to 200 K for the skeletal vibration of 36 linear macromolecules. The trained network could then accurately extract both parameters of the Tarasov function (THETA-1 and THETA-3) from heat capacities of three computed test cases and a set of experimental measurements for polyethylene. The neural network method offers a major improvement in handling heat capacity data. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. UNIV ARKANSAS,DEPT CHEM,LITTLE ROCK,AR 72204. RP NOID, DW (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 14 TC 13 Z9 13 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0368-4466 J9 J THERM ANAL JI J. Therm. Anal. PD OCT PY 1991 VL 37 IS 10 BP 2295 EP 2300 DI 10.1007/BF01913729 PG 6 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA HG935 UT WOS:A1991HG93500007 ER PT J AU Eddy, TL AF Eddy, T. L. TI Low-Pressure Plasma Spectroscopic Diagnostics SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB Diagnostic techniques have recently been developed that permit the determination of the deviation from local thermal equilibrium (LTE) in subatmospheric electric arcs and plasma jets. A review is presented of the methods that are applicable to MPD (magnetoplasmadynamic) and arcjet thruster plasmas but that have not been used in space propulsion research. Appropriate plasma diagnostics can lead to increased thrust, better nozzle design, and improved modeling capabilities. These methods include nonintrusive techniques, and can determine the electron, T-e, gas, T-g, and total excitation, T-exa, temperatures, as well as the electron and atom densities, without using LTE or partial LTE assumptions. General relations for analysis and experimental results for argon constricted arcs, an art in a rotating magnetic field, and plasma torch jets are presented. The methods discussed can also be applied to plasma mixtures. C1 [Eddy, T. L.] Georgia Inst Technol, Atlanta, GA 30332 USA. RP Eddy, TL (reprint author), EG&G Idaho Inc, Plasma Proc, Idaho Natl Engn Lab, POB 1625, Idaho Falls, ID 83415 USA. FU U.S. Department of Energy under DOE [DE-AC07-76ID01570] FX Without the excellent experimental work by A. Sedghinasab, R. V. Frierson, Ph. Roumilhac, and J. M. Leger, and the vision and support of P. Fauchais, this summary would not have been possible. The preparation of this paper was supported by the U.S. Department of Energy under DOE Contract DE-AC07-76ID01570. NR 24 TC 2 Z9 2 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD OCT-DEC PY 1991 VL 5 IS 4 BP 481 EP 488 DI 10.2514/3.290 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA V24ZX UT WOS:000208449400005 ER PT J AU HOLSTER, P JACOBS, J ROBLEE, J AF HOLSTER, P JACOBS, J ROBLEE, J TI THE MEASUREMENT AND FINITE-ELEMENT ANALYSIS OF THE DYNAMIC STIFFNESS OF NONUNIFORM CLEARANCE, GAS, THRUST-BEARINGS SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article AB This paper presents an overview of a finite-element-method (FEM) approach for the calculation of the dynamic stiffness of circular, externally pressurized gas thrust bearings with a nonuniform clearance. Some observations are made about the characteristic behavior of gas bearings subject to dynamic loading. The primary emphasis of this paper, however, is the development and qualification of a test apparatus and the necessary test techniques for measuring dynamic stiffness up to 250 N/mu-m at frequencies up to 2000 Hz. A thorough, experimental verification of the FEM model is reserved for a later paper. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP HOLSTER, P (reprint author), PHILIPS RES LABS,EINDHOVEN,NETHERLANDS. NR 13 TC 1 Z9 1 U1 1 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD OCT PY 1991 VL 113 IS 4 BP 768 EP 776 DI 10.1115/1.2920691 PG 9 WC Engineering, Mechanical SC Engineering GA GM025 UT WOS:A1991GM02500016 ER PT J AU CHEN, YR LEESMILLER, SP TEGTMEYER, P ANDERSON, CW AF CHEN, YR LEESMILLER, SP TEGTMEYER, P ANDERSON, CW TI THE HUMAN DNA-ACTIVATED PROTEIN-KINASE PHOSPHORYLATES SIMIAN VIRUS-40 T-ANTIGEN AT AMINO-TERMINAL AND CARBOXY-TERMINAL SITES SO JOURNAL OF VIROLOGY LA English DT Article ID LARGE TUMOR-ANTIGEN; SV40 LARGE-T; HEAT-SHOCK PROTEIN; MONOCLONAL-ANTIBODIES; BINDING DOMAIN; INSECT CELLS; REPLICATION ACTIVITY; EARLY TRANSCRIPTION; HELICASE ACTIVITIES; REGULATORY MUTANTS AB Protein phosphorylation modulates the function of simian virus 40 large T antigen (TAg) in productive and transforming infections. We recently described a DNA-activated protein kinase (DNA-PK) that efficiently phosphorylates TAg and several other nuclear, DNA-binding proteins in vitro (S. P. Lees-Miller, Y.-R. Chen, and C. W. Anderson, Mol. Cell. Biol. 10:6472-6481, 1990). In this report, we show by direct amino acid sequence analysis that DNA-PK phosphorylates TAg strongly at Ser-677, a residue known to be important for TAg interaction with origin site I and for transformation. We propose that DNA-PK may modulate the role of TAg in repressing early viral transcription and cell transformation, but a role for DNA-PK in regulating simian virus 40 DNA synthesis is not excluded. DNA-PK also phosphorylates Ser-665, and Ser-667, and one or more serines between amino acids 110 and 131. At least six serines, Ser-111, Ser-112, Ser-120, Ser-665, Ser-667, and Ser-677, are phosphorylated in TAg purified from baculovirus vector-infected insect cells. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. SUNY STONY BROOK,DEPT MICROBIOL,STONY BROOK,NY 11794. FU NCI NIH HHS [CA28146, CA18808]; NIAID NIH HHS [AI25170] NR 63 TC 40 Z9 40 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0022-538X J9 J VIROL JI J. Virol. PD OCT PY 1991 VL 65 IS 10 BP 5131 EP 5140 PG 10 WC Virology SC Virology GA GF097 UT WOS:A1991GF09700001 PM 1654434 ER PT J AU GARROTT, RA SINIFF, DB EBERHARDT, LL AF GARROTT, RA SINIFF, DB EBERHARDT, LL TI GROWTH-RATES OF FERAL HORSE POPULATIONS SO JOURNAL OF WILDLIFE MANAGEMENT LA English DT Article ID DYNAMICS; ACCURACY; COUNTS AB We studied growth rates of feral horse (Equus caballus) populations in the western United States by consolidating aerial count records for 103 management areas administered by the Bureau of Land Management (BLM). Data from most areas could not be used because of free exchange of horses between neighboring areas and/or inadequate or incomplete data. Twenty-two areas provided data that were used to assess the accuracy of aerial counts with the index-removal method. Most (24/31) aerial counts consistently detected a large proportion (85-105%) of the horses. Replicate index-removal estimates provided little evidence of progressively higher sighting probabilities that would inflate growth rate estimates, and we concluded that aerial counts could be used to obtain reliable estimates of population growth rates. We used log-linear regression to estimate finite annual growth rates (lambda). Estimates of lambda for 12 areas with adequate data ranged from 1.15 to 1.27 with a. mean of 1.21. Population simulations from age-specific reproduction and survival data collected independent of our study produced a similar range of growth rates. We concluded that many feral horse populations are currently being maintained at levels below which density-dependent responses operate and are, therefore, increasing at or near their biological maximum. C1 UNIV MINNESOTA, DEPT ECOL EVOLUT & BEHAV, MINNEAPOLIS, MN 55455 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP GARROTT, RA (reprint author), UNIV MINNESOTA, DEPT FISHERIES & WILDLIFE CONSERVAT, ST PAUL, MN 55108 USA. NR 35 TC 28 Z9 29 U1 3 U2 14 PU WILDLIFE SOC PI BETHESDA PA 5410 GROSVENOR LANE, BETHESDA, MD 20814-2197 SN 0022-541X J9 J WILDLIFE MANAGE JI J. Wildl. Manage. PD OCT PY 1991 VL 55 IS 4 BP 641 EP 648 DI 10.2307/3809513 PG 8 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA GW663 UT WOS:A1991GW66300017 ER PT J AU ERDEMIR, A BUSCH, DE ERCK, RA FENSKE, GR LEE, R AF ERDEMIR, A BUSCH, DE ERCK, RA FENSKE, GR LEE, R TI ION-BEAM-ASSISTED DEPOSITION OF SILVER FILMS ON ZIRCONIA CERAMICS FOR IMPROVED TRIBOLOGICAL BEHAVIOR SO LUBRICATION ENGINEERING LA English DT Article AB Silver coatings of 2-mu-m nominal thickness were deposited on toughened zirconia ceramics by ion-beam-assisted deposition (IBAD). Tribotests were performed with ball-on-disk machines under a load of 5 N, at velocities of 0.1 to 2 m.s-1, and in dry and normal air. The sliding friction coefficients of zirconia on itself ranged from 0.3 to 1.2, and the wear rates spanned more than three orders of magnitude, depending on the sliding velocity. In contrast, the wear of IBAD-silver-coated disks was practically unmeasurable, and the wear of zirconia balls was reduced by factors of 5 to 3300 below that of balls slid against uncoated zirconia disks. Large reductions in friction coefficients were also observed for the pairs that included an IBAD-silver film. Scanning-electron microscopy and laser-Raman spectroscopy were used to elucidate the mechanisms of wear of coated and uncoated ceramics. RP ERDEMIR, A (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,TRIBOL SECT,ARGONNE,IL 60439, USA. NR 0 TC 20 Z9 20 U1 0 U2 0 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 OCT PY 1991 VL 47 IS 10 BP 863 EP 872 PG 10 WC Engineering, Mechanical SC Engineering GA GJ549 UT WOS:A1991GJ54900009 ER PT J AU WALTERS, RT LEE, MW AF WALTERS, RT LEE, MW TI 2 PLATEAUS FOR PALLADIUM HYDRIDE AND THE EFFECT OF HELIUM FROM TRITIUM DECAY ON THE DESORPTION PLATEAU PRESSURE FOR PALLADIUM TRITIDE SO MATERIALS CHARACTERIZATION LA English DT Article ID METAL TRITIDES; X-RAY; HYDROGEN; HE-3 AB Two plateaux are observed in the desorption isotherm for palladium hydride: a lower plateau pressure for a hydrogen/metal atom ratio (H/M) less than about 0.3 and a slightly higher plateau pressure for H/M greater than about 0.3. This higher pressure corresponds to the reported pressure for palladium hydride. These observations were made for a large surface area palladium powder exposed to both protium and tritium. Helium buildup from tritium decay decreases the lower plateau pressure but does not affect the observations for H/M greater than about 0.3. A multiple-energy hydrogen site occupancy model is proposed to explain qualitatively both the dual plateau and the helium effect in palladium hydride. C1 WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER LAB,AIKEN,SC 29802. RP WALTERS, RT (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 21 TC 6 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1044-5803 J9 MATER CHARACT JI Mater. Charact. PD OCT PY 1991 VL 27 IS 3 BP 157 EP 166 DI 10.1016/1044-5803(91)90059-D PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA GU774 UT WOS:A1991GU77400006 ER PT J AU SUNWOO, AJ MORRIS, JW AF SUNWOO, AJ MORRIS, JW TI INFLUENCE OF INTRINSIC AND EXTRINSIC FACTORS ON MECHANICAL-PROPERTIES OF 2090-ALUMINUM ALLOY WELDMENTS SO MATERIALS SCIENCE AND TECHNOLOGY LA English DT Article ID AL-LI; ZR ALLOY; PRECIPITATION; FRACTURE AB Intrinsic and extrinsic factors that influence the mechanical properties of as welded weldments in an Al-Cu-Li alloy, 2090, have been investigated. Electron beam (EB) and gas tungsten arc (GTA) welds were produced in 2090-T3 and 2090-T8. The tensile properties of as welded and solutionised and aged weldments at 293 and 77 K are presented. The results show that differences in thermomechanical processing between the base metal and the fusion zone lead to inhomogeneities in the weldment microstructure and, consequently, differences in properties. In the as welded condition, the EB and GTA fusion zones lack the strengthening precipitates present in the base metal. As a result, increased base metal constraint on the as welded fusion zone confines the plastic deformation to within the weld and therefore the measured mechanical properties of the weldment are those of the weld material. After equivalent thermal processing, the properties of the EB and GTA weldments are as good as, or better than, those of the base metal. In the post-weld solutionised and overaged condition, the base metal lacks the volume fraction and homogeneity of strengthening precipitates found in the EB and GTA fusion zones, and as a result failure occurs in the base metal. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. NR 24 TC 2 Z9 2 U1 1 U2 1 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5DB SN 0267-0836 J9 MATER SCI TECH SER JI Mater. Sci. Technol. PD OCT PY 1991 VL 7 IS 10 BP 965 EP 971 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GR148 UT WOS:A1991GR14800009 ER PT J AU MORRIS, MD AF MORRIS, MD TI ON COUNTING THE NUMBER OF DATA PAIRS FOR SEMIVARIOGRAM ESTIMATION SO MATHEMATICAL GEOLOGY LA English DT Article DE KRIGING; MULTIVARIATE GAUSSIAN DISTRIBUTION; REGIONALIZED VARIABLE; SAMPLING DESIGN ID VARIOGRAM AB In planning spatial sampling studies for the purpose of estimating the semivariogram, the number of data pairs separated by a given distance is sometimes used as a comparative index of the precision which can be expected from a given sampling design. Because spatial data are correlated, this index can be unreliable. An alternative index which partially corrects for this correlation, the maximum equivalent uncorrelated pairs, is proposed for comparing spatial designs. The index is developed under the assumption that the underlying stochastic process is Gaussian and is appropriate when the (population) semivariogram is to be estimated by the sample semivariogram. RP MORRIS, MD (reprint author), OAK RIDGE NATL LAB,DIV EPM,MATH SCI SECT,BLDG 6012,POB 2008,OAK RIDGE,TN 37831, USA. NR 7 TC 15 Z9 15 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0882-8121 J9 MATH GEOL JI Math. Geol. PD OCT PY 1991 VL 23 IS 7 BP 929 EP 943 DI 10.1007/BF02066733 PG 15 WC Geosciences, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Geology; Mathematics GA GJ570 UT WOS:A1991GJ57000002 ER PT J AU KELLEY, CT WRIGHT, SJ AF KELLEY, CT WRIGHT, SJ TI SEQUENTIAL QUADRATIC-PROGRAMMING FOR CERTAIN PARAMETER-IDENTIFICATION PROBLEMS SO MATHEMATICAL PROGRAMMING LA English DT Article DE SEQUENTIAL QUADRATIC PROGRAMMING; PARAMETER IDENTIFICATION ID SUFFICIENT CONDITIONS; LOCAL MINIMUM; ORDER CONDITIONS; REGULARIZATION; DUALITY; SYSTEMS AB We analyze the method of sequential quadratic programming for equality constrained minimization problems in Hilbert spaces of functions, and for the discrete approximations of such problems in the context of an elliptic parameter identification problem. We show how the discretization can be constructed so as to preserve the convergence behavior of the iterates for the infinite dimensional problem in the finite dimensional approximations. We use the structure of the parameter identification problem to reduce the size of the linear system for the SQP step and verify nondegeneracy of the constraints. C1 ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. N CAROLINA STATE UNIV,DEPT MATH,RALEIGH,NC 27695. RP KELLEY, CT (reprint author), N CAROLINA STATE UNIV,CTR RES SCI COMP,RALEIGH,NC 27695, USA. RI Kelley, Carl/A-4549-2008 NR 18 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-5610 J9 MATH PROGRAM JI Math. Program. PD OCT PY 1991 VL 51 IS 3 BP 281 EP 305 DI 10.1007/BF01586941 PG 25 WC Computer Science, Software Engineering; Operations Research & Management Science; Mathematics, Applied SC Computer Science; Operations Research & Management Science; Mathematics GA GM357 UT WOS:A1991GM35700001 ER PT J AU SCULLY, JR VANDENAVYLE, JA CIESLAK, MJ ROMIG, AD HILLS, CR AF SCULLY, JR VANDENAVYLE, JA CIESLAK, MJ ROMIG, AD HILLS, CR TI THE INFLUENCE OF PALLADIUM ON THE HYDROGEN-ASSISTED CRACKING RESISTANCE OF PH-13-8 MO STAINLESS-STEEL SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID TRAPPING MODEL; IRON; DEUTERIUM; EMBRITTLEMENT; DIFFUSION; METALS; TRAPS; 49-506-DEGREES-C; SOLUBILITY; PERMEATION AB We compare the hydrogen-assisted cracking resistance of wrought PH 13-8 Mo stainless steel alloyed with 0.4 to 1.0 wt pct palladium to the conventional alloy when aged to yield strengths of 1170 to 1250 MPa. Intergranular hydrogen cracking is suppressed with Pd in both static load and constant extension rate tests conducted with electrochemical hydrogen charging. These results are analyzed to elucidate the role of Pd in suppressing intergranular cracking. Palladium is found both in substitutional solid solution in the martensitic phase and also in the form of randomly distributed PdAl precipitates in all Pd-modified alloys. Interfacial segregation of Pd to grain boundaries and lath boundaries is not observed at any levels above a detection limit of approximately 0.5 monolayers. Hydrogen permeation analyses indicate that hydrogen ingress is not inhibited by Pd but that apparent diffusion coefficients are lowered relative to the conventional alloy. Lower diffusion coefficients are consistent with the creation of a strong but reversible hydrogen trap, identified as the uniformly distributed PdAl phase. We hypothesize that PdAl trap sites force a redistribution of trapped hydrogen, which lowers the amount of interfacially segregated hydrogen at prior austenite grain boundaries for the electrochemical conditions applied. These assertions are supported by a simplistic trapping model for PH 13-8 Mo which shows that both the hydrogen trap binding energy and the trap density for the PdAl trapping site are greater than the hydrogen trap binding energy and density for prior austenite grain boundaries. C1 SANDIA NATL LABS,DEPT MET,TECH STAFF,ALBUQUERQUE,NM 87185. NR 59 TC 24 Z9 24 U1 0 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD OCT PY 1991 VL 22 IS 10 BP 2429 EP 2444 DI 10.1007/BF02665009 PG 16 WC Materials Science, Multidisciplinary SC Materials Science GA GJ165 UT WOS:A1991GJ16500027 ER PT J AU TRIVEDI, R MASON, JT VERHOEVEN, JD KURZ, W AF TRIVEDI, R MASON, JT VERHOEVEN, JD KURZ, W TI EUTECTIC SPACING SELECTION IN LEAD-BASED ALLOY SYSTEMS SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID PB-SN; FE-C; GROWTH; SOLIDIFICATION; STABILITY AB Directional solidification studies have been carried out in Pb-Au, Pb-Pd, Pd-Cd, and Pb-Sn systems to characterize the variation in eutectic spacing with velocity. In the Pb-Cd, Pb-Sn, and Pb-Pd systems, statistical distributions of spacings at each velocity were determined and a significant spread was observed. The smallest and the largest spacings, along with the average spacing, have been characterized. A broad distribution curve has been observed for low velocities which becomes sharper as the velocities increase. A comparison with the theoretical model shows that the average spacings are consistently larger than the spacings predicted by the minimum undercooling criterion, whereas the smallest observed spacing corresponds to the theoretical extremum value. Dynamical studies have been carried out to examine the spacing selection process at a given velocity by initially starting with a higher or a lower average spacing. The final spacing distribution at a given velocity was found to be the same irrespective of the initial starting condition which establishes that a definite distribution of spacings exists in eutectic systems without any hysteresis effect and that dynamical effects are not responsible for the existence of a band of stable spacing. C1 SWISS FED INST TECHNOL,DEPT MAT ENGN,CH-1007 LAUSANNE,SWITZERLAND. RP TRIVEDI, R (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 40 TC 80 Z9 83 U1 0 U2 13 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD OCT PY 1991 VL 22 IS 10 BP 2523 EP 2533 DI 10.1007/BF02665018 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA GJ165 UT WOS:A1991GJ16500036 ER PT J AU MCGINNIS, DP AF MCGINNIS, DP TI THEORY AND DESIGN OF MICROWAVE PLANAR ELECTRODES FOR STOCHASTIC COOLING OF PARTICLE BEAMS SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article DE STOCHASTIC COOLING; ANTIPROTONS; PLANAR LOOP AB Stochastic cooling is a broadband microwave feedback system used in particle accelerators to reduce beam size growth. Because stochastic cooling is a random process, the performance of the system is directly proportional to the bandwidth of the system. Electrodes that sense and correct the position of particles in the beam must accommodate octave bandwidths in the range from 1 to 16 GHz. This article will outline the theory, design, and measurements of planar electrodes that achieve these wide bandwidths. RP MCGINNIS, DP (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD OCT PY 1991 VL 4 IS 11 BP 439 EP 443 DI 10.1002/mop.4650041107 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA GH829 UT WOS:A1991GH82900006 ER PT J AU LEE, C MAZRIMAS, J BALHORN, R AF LEE, C MAZRIMAS, J BALHORN, R TI ANALYSIS OF PROTAMINES ISOLATED FROM ALCOHOL PRESERVED EPIDIDYMIDES SO MOLECULAR REPRODUCTION AND DEVELOPMENT LA English DT Article DE SPERM; PRESERVED TISSUE; HAMSTER; MESOCRICETUS-AURATUS; ISOPROPANOL ID AMINO-ACID-SEQUENCES; SPERM; PROTEINS; MOUSE; CHROMATIN; SPERMATOZOA AB Protamines 1 and 2 have been isolated from the sperm of frozen and isopropanol preserved Syrian hamster (Mesocricetus auratus) epididymides and analyzed by gel electrophoresis, high-performance liquid chromatography (HPLC), and amino acid analysis and sequencing. The results show that alcohol preservation does not alter the primary structure of the two sperm nuclear proteins and that the preservation of mammalian reproductive organs in alcohol is a viable alternative to freezing tissues collected in the field. Sperm were isolated from tissues fixed in isopropanol for as long as 7 months without detectable adverse effects on either the isolation of sperm or the primary structure of the protamines. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. NR 20 TC 9 Z9 9 U1 2 U2 5 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 1040-452X J9 MOL REPROD DEV JI Mol. Reprod. Dev. PD OCT PY 1991 VL 30 IS 2 BP 154 EP 158 DI 10.1002/mrd.1080300212 PG 5 WC Biochemistry & Molecular Biology; Cell Biology; Developmental Biology; Reproductive Biology SC Biochemistry & Molecular Biology; Cell Biology; Developmental Biology; Reproductive Biology GA GH824 UT WOS:A1991GH82400011 PM 1954029 ER PT J AU FONTANA, W GRIESMACHER, T SCHNABL, W STADLER, PF SCHUSTER, P AF FONTANA, W GRIESMACHER, T SCHNABL, W STADLER, PF SCHUSTER, P TI STATISTICS OF LANDSCAPES BASED ON FREE-ENERGIES, REPLICATION AND DEGRADATION RATE CONSTANTS OF RNA SECONDARY STRUCTURES SO MONATSHEFTE FUR CHEMIE LA English DT Article DE RNA SECONDARY STRUCTURES; RNA FREE ENERGIES; VALUE LANDSCAPES; AUTOCORRELATION FUNCTIONS; CORRELATION LENGTHS ID EVOLUTIONARY OPTIMIZATION; RUGGED LANDSCAPES; SELECTION; SEQUENCES; PREDICTIONS; STABILITY; LIGANDS; MODEL AB RNA secondary structures are computed from primary sequences by means of a folding algorithm which uses a minimum free energy criterion. Free energies as well as replication and degradation rate constants are derived from secondary structures. These properties can be understood as highly sophisticated functions of the individual sequences whose values are mediated by the secondary structures. Such functions induce complex value landscapes on the space of sequences. The landscapes are analysed by random walk techniques, in particular autocorrelation functions and correlation lengths are computed. Free energy landscapes were found to be of AR(1) type. The rate constant landscapes, however, turned out to be more complex. In addition, gradient and adaptive walks are performed in order to get more insight into the complex structure of the landscapes. C1 UNIV VIENNA, INST THEORET CHEM, A-1090 VIENNA, AUSTRIA. SANTA FE INST, SANTA FE, NM USA. UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87544 USA. OI Stadler, Peter F./0000-0002-5016-5191 NR 45 TC 47 Z9 47 U1 1 U2 2 PU SPRINGER WIEN PI WIEN PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 WIEN, AUSTRIA SN 0026-9247 EI 1434-4475 J9 MONATSH CHEM JI Mon. Chem. PD OCT PY 1991 VL 122 IS 10 BP 795 EP 819 PG 25 WC Chemistry, Multidisciplinary SC Chemistry GA GR146 UT WOS:A1991GR14600005 ER PT J AU NICHOLS, FA AF NICHOLS, FA TI WHAT IS TRIBOLOGY, ANYWAY SO MRS BULLETIN LA English DT Editorial Material RP NICHOLS, FA (reprint author), ARGONNE NATL LAB,US DOE TRIBOL PROGRAM,ARGONNE,IL 60439, USA. NR 0 TC 2 Z9 2 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 OCT PY 1991 VL 16 IS 10 BP 30 EP 32 PG 3 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA GK666 UT WOS:A1991GK66600002 ER PT J AU ERDEMIR, A NICHOLS, FA FENSKE, GR HSIEH, JH AF ERDEMIR, A NICHOLS, FA FENSKE, GR HSIEH, JH TI SLIDING FRICTION AND WEAR OF CERAMICS WITH AND WITHOUT SOFT METALLIC-FILMS SO MRS BULLETIN LA English DT Article RP ERDEMIR, A (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,TRIBOL SECT,ARGONNE,IL 60439, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD OCT PY 1991 VL 16 IS 10 BP 49 EP 53 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA GK666 UT WOS:A1991GK66600006 ER PT J AU HAY, PJ AF HAY, PJ TI THE MODEL REACTION PT(PH3)2 + H2 REVISITED INFLUENCE OF OUTER CORE ORBITALS ON ELECTRON CORRELATION-EFFECTS USING RELATIVISTIC EFFECTIVE CORE POTENTIALS SO NEW JOURNAL OF CHEMISTRY LA English DT Article ID EFFECTIVE CORE POTENTIALS; REDUCTIVE ELIMINATION; OXIDATIVE ADDITION; COMPLEXES; CIS; PLATINUM(II); PALLADIUM; HYDROGEN AB The oxidative addition of H-2 to d10 ML2 systems is reinvestigated for the model system Pt(PH3)2 which has been the topic of several theoretical studies. The current treatment differs from earlier ones in that "norm-conserving" relativistic effective core potentials (ECPs) are used and that the 5s and 5p core electrons are explicitly included in the calculation. The geometries of reactants, transition state and cis addition product were optimized at the Hartree-Fock level, and electron correlation effects were included by configuration interaction techniques involving all single and double excitations. The importance of using ECPs which include the outermost core electrons (5s and 5p for Pt) is emphasized when performing calculations including electron correlation effects on transition metal systems. RP HAY, PJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 30 TC 18 Z9 18 U1 0 U2 0 PU GAUTHIER-VILLARS PI PARIS PA S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE SN 1144-0546 J9 NEW J CHEM JI New J. Chem. PD OCT-NOV PY 1991 VL 15 IS 10-11 BP 735 EP 740 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA HB973 UT WOS:A1991HB97300007 ER PT J AU BRINKER, CJ HURD, AJ FRYE, GC SCHUNK, PR ASHLEY, CS BRINKER, CJ HURD, AJ FRYE, GC SCHUNK, PR ASHLEY, CS AF BRINKER, CJ HURD, AJ FRYE, GC SCHUNK, PR ASHLEY, CS BRINKER, CJ HURD, AJ FRYE, GC SCHUNK, PR ASHLEY, CS TI SOL-GEL THIN-FILM FORMATION SO NIPPON SERAMIKKUSU KYOKAI GAKUJUTSU RONBUNSHI-JOURNAL OF THE CERAMIC SOCIETY OF JAPAN LA English DT Article DE SOL-GEL; DIP-COATING; SPIN-COATING; MICROSTRUCTURE; FILMS AB Sol-gel thin film formation by dipping (or spinning) involves gravitational (or centrifugal) draining accompanied by vigorous solvent evaporation. During dipping a steady-state film thickness profile develops, the shape of which is established by the evaporation rates of the fluid components and possible surface tension gradient driven flows. The entrained inorganic species are concentrated by the accompanying evaporation of solvent and compacted by capillary pressure developed at the final stage of the deposition process as liquid-vapor menisci recede into the gel interior. The important microstructural properties of the deposited film (% porosity, surface area, and pore size) depend on the size and structure of the inorganic species, the relative rates of condensation and evaporation during deposition, the magnitude of the capillary pressure, and the accompanying shear stress. RP BRINKER, CJ (reprint author), SANDIA NATL LABS,DIV INORGAN MAT CHEM 1846,ALBUQUERQUE,NM 87185, USA. NR 0 TC 11 Z9 11 U1 4 U2 18 PU CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI PI TOKYO PA 22-17 HYAKUNIN-CHO SHINJUKU-KU, TOKYO 169, JAPAN SN 0914-5400 J9 NIPPON SERAM KYO GAK PD OCT PY 1991 VL 99 IS 10 BP 862 EP 877 PG 16 WC Materials Science, Ceramics SC Materials Science GA GK934 UT WOS:A1991GK93400006 ER PT J AU BECHER, PF AF BECHER, PF TI ADVANCES IN THE DESIGN OF TOUGHENED CERAMICS SO NIPPON SERAMIKKUSU KYOKAI GAKUJUTSU RONBUNSHI-JOURNAL OF THE CERAMIC SOCIETY OF JAPAN LA English DT Article DE TOUGHNESS; CRACK BRIDGING; TRANSFORMATION; MICROSTRUCTURE; MECHANICAL PROPERTIES AB The mechanical performance of brittle ceramics can be improved by increasing their fracture toughness/resistance. This is reflected by increases in resistance to strength degradation from in-service thermal stresses, slow crack growth, and contact or impact damage when the fracture toughness is enhanced. Furthermore, it appears that the distribution of the fracture strengths is narrowed (e.g., increased Weibull modulus) in toughened ceramics. Two approaches which can result in improved fracture toughness are transformation toughening and reinforcement processes. The reinforcement process can be achieved by introducing various microstructural features (e.g., strong whiskers and platelets, large noncubic matrix grains, and elongated matrix grains). However, the design of toughened ceramics employing either transformation toughening or reinforcement mechanisms must consider the material properties and characteristics which control each mechanism. Both the analysis of the toughening contributions and experimental observations can be used to define the influence of microstructure and material parameters on the toughening effects. These observations, then, provide a basis for the design of toughened ceramics. RP BECHER, PF (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,STRUCT CERAM GRP,OAK RIDGE,TN 37830, USA. NR 0 TC 10 Z9 10 U1 1 U2 6 PU CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI PI TOKYO PA 22-17 HYAKUNIN-CHO SHINJUKU-KU, TOKYO 169, JAPAN SN 0914-5400 J9 NIPPON SERAM KYO GAK PD OCT PY 1991 VL 99 IS 10 BP 993 EP 1001 PG 9 WC Materials Science, Ceramics SC Materials Science GA GK934 UT WOS:A1991GK93400017 ER PT J AU RITCHIE, RO DAUSKARDT, RH AF RITCHIE, RO DAUSKARDT, RH TI CYCLIC FATIGUE OF CERAMICS - A FRACTURE-MECHANICS APPROACH TO SUBCRITICAL CRACK-GROWTH AND LIFE PREDICTION SO NIPPON SERAMIKKUSU KYOKAI GAKUJUTSU RONBUNSHI-JOURNAL OF THE CERAMIC SOCIETY OF JAPAN LA English DT Article DE CYCLIC FATIGUE; CRACK GROWTH; SMALL CRACKS; FATIGUE THRESHOLD; CERAMICS; CERAMIC-MATRIX COMPOSITES; MG-PSZ; ALUMINA; SILICON NITRIDE; SIC-REINFORCED ALUMINA; PYROLYTIC-CARBON; GRAPHITE LAMINATE; DAMAGE-TOLERANT DESIGN; LIFE PREDICTION AB Cyclic fatigue, and specifically fatigue-crack propagation, in ceramic materials is reviewed both for monolithic and composites systems. In particular, stress/life (S/N) and crack-propagation data are presented for a range of ceramics, including zirconia, alumina, silicon nitride, SiC-whisker-reinforced alumina and a pyrolytic-carbon/graphite laminate. S/N data derived from unnotched specimens often indicate markedly lower lives under tension-compression compared to tension-tension loading; similar to metals, 10(8)-cycle "fatigue limits" generally approach approximately 50% of the tensile strength. Crack-growth results, based on studies on "long" (> 3 mm) cracks, show fatigue-crack propagation rates to be markedly power-law dependent on the applied stress-intensity range, DELTA-K, with a threshold, DELTA-K(TH), of the order of approximately 50% of K(c). Conversely, for "small" (< 250-mu-m) surface cracks, fatigue-crack growth is seen to occur at DELTA-K levels some 2 to 3 times smaller than DELTA-K(TH) and to show a negative dependency on applied stress intensity. At ambient temperatures, lifetimes are shortened and crack-growth rates are significantly accelerated by cyclic, compared to quasi-static loading, although limited data suggest the reverse to be true at very high temperatures in the creep regime. Such results are discussed in terms of the primary crack-tip shielding (toughening) mechanisms and potential mechanisms of cyclic crack advance. Finally, implications are discussed of long and small crack cyclic fatigue data to life prediction and safety-critical design of ceramic components. RP RITCHIE, RO (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR ADV MAT,BERKELEY,CA 94720, USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 0 TC 72 Z9 72 U1 1 U2 12 PU CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI PI TOKYO PA 22-17 HYAKUNIN-CHO SHINJUKU-KU, TOKYO 169, JAPAN SN 0914-5400 J9 NIPPON SERAM KYO GAK PD OCT PY 1991 VL 99 IS 10 BP 1047 EP 1062 PG 16 WC Materials Science, Ceramics SC Materials Science GA GK934 UT WOS:A1991GK93400022 ER PT J AU RAMSEY, AT BUSH, CE DYLLA, HF OWENS, DK PITCHER, CS ULRICKSON, MA AF RAMSEY, AT BUSH, CE DYLLA, HF OWENS, DK PITCHER, CS ULRICKSON, MA TI ENHANCED CARBON INFLUX INTO TFTR SUPERSHOTS SO NUCLEAR FUSION LA English DT Article ID GRAPHITE; SUBLIMATION; TEMPERATURES; EROSION; IONS AB Under some conditions, a very large influx of carbon into TFTR occurs during neutral beam injection into low recycling plasmas (the supershot regime). These carbon 'blooms' result in serious degradation of plasma parameters. The sources of this carbon have been identified as hot spots on the TFTR bumper limiter at or near the last closed flux surface. Two separate temperature thresholds have been identified. One threshold, at about 1650-degrees-C, is consistent with radiation enhanced sublimation (RES). The other, at about 2300-degrees-C, appears to be thermal sublimation of carbon from the limiter. The carbon influx can be quantitatively accounted for by taking laboratory values for RES rates, making reasonable assumptions about the extent of the blooming area and assuming unity carbon recycling at the limiter. Such high carbon recycling is expected, and it is shown that, in target plasmas at least, it is observed on TFTR. The sources of the carbon blooms are sites which have either loosely attached fragments of limiter material (caused by damage) or surfaces that are nearly perpendicular to the magnetic field lines. Such surfaces may have local power depositions two orders of magnitude higher than usual. The TFTR team modified the limiter during the opening of winter 1989-1990. The modifications greatly reduced the number and magnitude of the blooms, so that they are no longer a problem. C1 CONTINUOUS ELECTRON BEAM ACCELERATOR FACIL,NEWPORT NEWS,VA. CANADIAN FUS FUELS TECHNOL PROJECT,TORONTO,ONTARIO,CANADA. RP RAMSEY, AT (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544, USA. NR 27 TC 36 Z9 36 U1 0 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD OCT PY 1991 VL 31 IS 10 BP 1811 EP 1825 DI 10.1088/0029-5515/31/10/001 PG 15 WC Physics, Fluids & Plasmas SC Physics GA GP406 UT WOS:A1991GP40600001 ER PT J AU CHARLTON, LA BAYLOR, LR EDWARDS, AW HAMMETT, GW HOULBERG, WA KUPSCHUS, P LYNCH, VE MILORA, SL OROURKE, J SCHMIDT, GL AF CHARLTON, LA BAYLOR, LR EDWARDS, AW HAMMETT, GW HOULBERG, WA KUPSCHUS, P LYNCH, VE MILORA, SL OROURKE, J SCHMIDT, GL TI THEORETICAL-ANALYSIS OF THE ROLE OF THE INFERNAL MODE IN THE STABILITY OF PEAKED PRESSURE PROFILES IN PELLET FUELED JET DISCHARGES SO NUCLEAR FUSION LA English DT Article AB The very peaked pressure profiles in some pellet fuelled discharges with ion cyclotron resonance heating in the Joint European Torus (JET) are terminated by an abrupt flattening of the temperature profile. This appears to be the result of an instability with a very fast time-scale that is triggered when the safety factor q drops below 1.5. The ideal m/n = 3/2 infernal mode, which is excited only when q is very close to 1.5, may well be the responsible instability. Linear magnetohydrodynamic stability calculations, based on equilibria that model the relevant JET discharges as closely as possible, yield growth rates consistent with the rise time of the instability. Non-linear calculations initialized with the same equilibria exhibit plasma behaviour very similar to that seen experimentally: (1) a flattening of the pressure profile occurs, (2) a residual m = 3 structure is present after the flattening, and (3) the time-scale for the flattening is in reasonable agreement with experimental observations. It is thus concluded that the ideal infernal mode is a viable candidate for the instability. C1 JET JOINT UNDERTAKING,ABINGDON,OXON,ENGLAND. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ. RP CHARLTON, LA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Hammett, Gregory/D-1365-2011; Lynch, Vickie/J-4647-2012 OI Hammett, Gregory/0000-0003-1495-6647; Lynch, Vickie/0000-0002-5836-7636 NR 9 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 OCT PY 1991 VL 31 IS 10 BP 1835 EP 1842 DI 10.1088/0029-5515/31/10/003 PG 8 WC Physics, Fluids & Plasmas SC Physics GA GP406 UT WOS:A1991GP40600003 ER PT J AU PERRY, ME BROOKS, NH CONTENT, DA HULSE, RA MAHDAVI, MA MOOS, HW AF PERRY, ME BROOKS, NH CONTENT, DA HULSE, RA MAHDAVI, MA MOOS, HW TI IMPURITY TRANSPORT DURING THE H-MODE IN DIII-D SO NUCLEAR FUSION LA English DT Article ID ALCATOR-C TOKAMAK; ENERGY CONFINEMENT; DISCHARGES; PLASMAS; INJECTION; BEHAVIOR; PROFILES; ACCUMULATION; RADIATION AB In H-mode plasmas in DIII-D, large modulations in spectroscopically measured impurity densities have been observed during shots with giant edge localized modes (ELMs). These spectral modulations have been analysed with the MIST impurity transport code. This analysis indicates that impurities are alternately flowing towards the plasma centre and then away from it. This alternating flow is correlated with ELM produced changes in the electron density. The electron density oscillations are extreme, causing the density profile to switch from hollow (just before an ELM) to centrally peaked (just after an ELM). Neoclassical convection, dependent on ion density gradients, causes impurities to concentrate most heavily where the electron density is largest and can explain the modulating impurity behaviour. Anomalous diffusion, D congruent-to 1.0 x 10(4) cm2/s, reduces the degree of impurity peaking. As the plasma current increases, the increase in hollowness of electron density profiles can account for the observed decrease in central impurity accumulation. Transport of cobalt, injected by laser ablation, has also been studied; cobalt transport variations are consistent with the ELM induced changes seen in intrinsic impurity transport. The transport results may be consistent with neoclassical impurity convective fluxes and suggest that impurity accumulation in tokamaks will occur unless the electron density profile is flat or particle confinement is low. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,34TH & N CHARLES,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP PERRY, ME (reprint author), GEN ATOM CO,SAN DIEGO,CA 92138, USA. RI Perry, Mark/B-8870-2016 OI Perry, Mark/0000-0003-1600-6856 NR 50 TC 24 Z9 24 U1 1 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD OCT PY 1991 VL 31 IS 10 BP 1859 EP 1875 DI 10.1088/0029-5515/31/10/005 PG 17 WC Physics, Fluids & Plasmas SC Physics GA GP406 UT WOS:A1991GP40600005 ER PT J AU EHST, DA KARNEY, CFF AF EHST, DA KARNEY, CFF TI APPROXIMATE FORMULA FOR RADIOFREQUENCY CURRENT DRIVE EFFICIENCY WITH MAGNETIC TRAPPING SO NUCLEAR FUSION LA English DT Letter ID WAVE CURRENT DRIVE; RF CURRENT DRIVE; CURRENT GENERATION; EQUILIBRIUM; ELECTRONS; TOKAMAKS; PLASMAS AB A functional form is presented for the efficiency of current drive in toroidal geometry with waves at frequencies below the electron cyclotron frequency. By fitting constants in order to duplicate numerical results for the efficiency, an accurate function is obtained which will be useful for computer calculations of current drive. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544. RP EHST, DA (reprint author), ARGONNE NATL LAB,FUS POWER PROGRAM,ARGONNE,IL 60439, USA. RI Karney, Charles/C-1371-2013 OI Karney, Charles/0000-0002-5006-5836 NR 12 TC 95 Z9 96 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 OCT PY 1991 VL 31 IS 10 BP 1933 EP 1938 DI 10.1088/0029-5515/31/10/011 PG 6 WC Physics, Fluids & Plasmas SC Physics GA GP406 UT WOS:A1991GP40600011 ER PT J AU NAKAI, S SOURES, JM UEDA, K SUDAN, RN VELARDE, G NAKAI, S BANNER, DL BASOV, NG CHENEVERT, GM DAUTRAY, R KEY, M VELARDE, G WITKOWSKI, S YAMANAKA, C AF NAKAI, S SOURES, JM UEDA, K SUDAN, RN VELARDE, G NAKAI, S BANNER, DL BASOV, NG CHENEVERT, GM DAUTRAY, R KEY, M VELARDE, G WITKOWSKI, S YAMANAKA, C TI DRIVERS FOR INERTIAL CONFINEMENT FUSION - REPORT ON THE IAEA TECHNICAL COMMITTEE MEETING HELD AT OSAKA, JAPAN, 15-19 APRIL 1991 SO NUCLEAR FUSION LA English DT Editorial Material C1 UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14627. UNIV ELECTRO-COMMUN,INST LASER SCI,CHOFU,JAPAN. CORNELL UNIV,PLASMA STUDIES LAB,ITHACA,NY 14853. UNIV POLITECN MADRID,INST FUS NUCL,MADRID,SPAIN. INT ATOM ENERGY AGCY,PHYS SECT,A-1011 VIENNA,AUSTRIA. PN LEBEDEV PHYS INST,MOSCOW,USSR. US DOE,WASHINGTON,DC. CEA,CTR ETUD LIMEIL VALENTON,F-94190 VILLENEUVE,FRANCE. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV POLITECN MADRID,INST FUS NUCL,MADRID,SPAIN. MAX PLANCK INST QUANTUM OPT,W-8046 GARCHING,GERMANY. INST LASER TECHNOL,OSAKA,JAPAN. RP NAKAI, S (reprint author), OSAKA UNIV,INST LASER ENG,OSAKA,JAPAN. NR 0 TC 0 Z9 0 U1 1 U2 2 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD OCT PY 1991 VL 31 IS 10 BP 2005 EP 2011 DI 10.1088/0029-5515/31/10/015 PG 7 WC Physics, Fluids & Plasmas SC Physics GA GP406 UT WOS:A1991GP40600015 ER PT J AU BOZOKI, ES HALAMA, H AF BOZOKI, ES HALAMA, H TI ION RELATED PROBLEMS FOR THE XLS RING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The electron beam in a storage ring collides with the residual gas in the vacuum chamber. As a consequence, low velocity positive ions are produced and trapped in the potential well of the electron beam. They perform stable or unstable oscillations around the beam under the repetitive Coulomb force of the bunches. If not cleared, the captured ions can lead to partial or total neutralization of the beam, causing both a decrease of lifetime and a change in the vertical tunes as well as an increase in the tune spread. It can also cause coherent and incoherent transverse instabilities. An electrostatic clearing electrodes system was designed to keep the neutralization below a desired limit. The location and the geometry of the clearing electrodes as well as the applied clearing voltage is based on the study of the ion production rate, longitudinal velocity of ions in field-free regions and in the dipoles, beam self-electric field, beam potential, critical mass for ion capture in the bunched beam and the bounce frequencies of the ions, tune shift and pressure rise due to trapped ions. RP BOZOKI, ES (reprint author), BROOKHAVEN NATL LAB,NSLS,BLDG 725C,UPTON,NY 11973, USA. NR 19 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 OCT 1 PY 1991 VL 307 IS 2-3 BP 156 EP 166 DI 10.1016/0168-9002(91)90177-R PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800002 ER PT J AU BOZOKI, ES AF BOZOKI, ES TI DETERMINATION OF BEAM POSITION FROM INDUCED ELECTRIC SIGNALS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB At the NSLS storage rings capacitive pickups (PUEs) with four circular electrodes are used as beam position monitors. The dependence of the induced signal on the actual beam position for the geometry of the vacuum chamber and electrodes is studied both theoretically and experimentally. Four different methods for solving the Dirichlet problem for the NSLS geometry are presented and compared with each other as well as with the measured data. The first method is based on the separation of variables, the next two on conformal mapping and the last one on modeling with the Poisson program. Two sets of bench measurements of the PUE response as a function of the beam position were performed and the results are shown. The PUE response, in accordance with the calculations, is highly nonlinear except around the center of the vacuum chamber. A noniterative method is presented to calculate the beam position from this nonlinear response. RP BOZOKI, ES (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 195 EP 206 DI 10.1016/0168-9002(91)90183-Q PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800008 ER PT J AU JAMES, M DONAHUE, R MILLER, R NELSON, WR AF JAMES, M DONAHUE, R MILLER, R NELSON, WR TI A NEW TARGET DESIGN AND CAPTURE STRATEGY FOR HIGH-YIELD POSITRON PRODUCTION IN ELECTRON LINEAR COLLIDERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Monte Carlo calculations were performed using EGS4 to simulate the production of positons by a high-energy electron beam incident on thin wire targets. A 1 mm diameter, 10 radiation length long tungsten-alloy wire was chosen as an optimal target. The new target, combined with an appropriate capture strategy, could triple the yield of the high-energy positron production systems currently in use. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. NR 7 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 207 EP 212 DI 10.1016/0168-9002(91)90184-R PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800009 ER PT J AU BROMBERG, C BROWN, D HUSTON, J MAUL, A MILLER, R NYUGEN, A SORRELL, L YOSEF, C MANI, S CHOUDHARY, BC KAPOOR, V SHIVPURI, R BAKER, W DESOI, W JOHNSTONE, C KOURBANIS, I LUKENS, P SKOW, D WU, GH ALVERSON, G CHANG, P DLUGOSZ, W FAISSLER, W GARELICK, D GLAUBMAN, M LIRAKIS, C POTHIER, E YASUDA, T GUTIERREZ, P HARTMAN, K OH, BY TOOTHACKER, W WHITMORE, J BLUSK, SR CHUNG, WH ENGELS, E SHEPARD, PF WEERASUNDARA, DDS DEBARBARO, L DUNLEA, J FANOURAKIS, G FERBEL, T GINTHER, G LOBKOWICZ, F MANSOUR, J PREBYS, E ROSER, R SLATTERY, P VARELAS, N ZIELINSKI, M AF BROMBERG, C BROWN, D HUSTON, J MAUL, A MILLER, R NYUGEN, A SORRELL, L YOSEF, C MANI, S CHOUDHARY, BC KAPOOR, V SHIVPURI, R BAKER, W DESOI, W JOHNSTONE, C KOURBANIS, I LUKENS, P SKOW, D WU, GH ALVERSON, G CHANG, P DLUGOSZ, W FAISSLER, W GARELICK, D GLAUBMAN, M LIRAKIS, C POTHIER, E YASUDA, T GUTIERREZ, P HARTMAN, K OH, BY TOOTHACKER, W WHITMORE, J BLUSK, SR CHUNG, WH ENGELS, E SHEPARD, PF WEERASUNDARA, DDS DEBARBARO, L DUNLEA, J FANOURAKIS, G FERBEL, T GINTHER, G LOBKOWICZ, F MANSOUR, J PREBYS, E ROSER, R SLATTERY, P VARELAS, N ZIELINSKI, M TI DESIGN AND OPERATION OF LARGE STRAW-TUBE DRIFT CHAMBER PLANES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ALUMINIZED MYLAR TUBES; VERTEX CHAMBER; DETECTOR; CONSTRUCTION; PERFORMANCE AB We describe the design, construction and operation of a straw-tube drift chamber consisting of four X and four Y planes of 16 mm diameter straw-tubes, each 280 cm long. Straws were glued together for rigidity and were mounted into a frame which served as a gas manifold and maintained wire-to-wire precision. A novel conductive gasket was used to seal the tubes and provide electrical contact to the aluminized surface of the straws. The chamber has been successfully used in a high rate experiment (E706 at Fermilab) and has achieved its design resolution of better than 250-mu-m per tube averaged over the whole chamber. C1 UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. UNIV DELHI,DEPT PHYS & ASTROPHYS,DELHI 110007,INDIA. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. NORTHEASTERN UNIV,DEPT PHYS,BOSTON,MA 02115. UNIV OKLAHOMA,DEPT PHYS & ASTRON,NORMAN,OK 73019. PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. UNIV PITTSBURGH,DEPT PHYS & ASTRON,PITTSBURGH,PA 15260. UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627. RP BROMBERG, C (reprint author), MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824, USA. RI Gutierrez, Phillip/C-1161-2011 NR 8 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 292 EP 297 DI 10.1016/0168-9002(91)90195-V PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800020 ER PT J AU ROBINSON, RA CARPENTER, JM AF ROBINSON, RA CARPENTER, JM TI ON THE USE OF SWITCH FUNCTIONS IN DESCRIBING PULSED NEUTRON MODERATORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SHAPES AB In describing the energy spectrum of neutrons emanating from small pulsed hydrogenous moderators, it is normal practice to think of a sum of a "Maxwellian" component and a "1/E" or "slowing-down" component. A simple addition of these two components would give an infrared catastrophe and therefore the 1/E component is multiplied by a switch function, DELTA-(E), that suppresses it at low energies. Furthermore, in describing the time distribution for neutrons of a given energy, the same basic physical idea has been used, namely that there is a short pulse, which is identified with the slowing-down component, and a longer decay component, which is identified with thermalised neutrons. This has been done by using a different switch function R(E), which describes the proportion of the total intensity at any given energy in the Maxwellian or thermalised component. While these two descriptions give good fits to the observed spectra and pulse-shapes, they are independent and no attempt had been made to make them consistent with each other. In this article, we show that the current functional forms for DELTA and R are inconsistent with each other and we discuss the necessary ingredients for a unified switch function description. The intent is to construct a simultaneous parametric description for the spectrum and lineshapes of pulsed moderators. One could then predict how the flux and time parametric description for the spectrum and lineshapes of pulsed moderators. One could then predict how the flux and time distributions vary, as the poison depth is changed, in a systematic way. This would be useful in optimising a moderator as one component in the optimisation of a complete spectrometer. We show that it is possible to find such a unified description, but that it is only accurate to within 25% for methane and to within 50% for polyethylene. We discuss these discrepancies in terms of fundamental theory. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP ROBINSON, RA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 359 EP 365 DI 10.1016/0168-9002(91)90205-5 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800030 ER PT J AU REFFO, G MACGREGOR, MH KOMOTO, T AF REFFO, G MACGREGOR, MH KOMOTO, T TI FAST-NEUTRON-INDUCED CROSS-SECTIONS ON NE-20 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB An evaluation is presented of neutron-induced reaction cross sections on Ne-20 in the energy range 1-30 MeV. The theoretical nuclear model and the computer codes used are briefly described, together with the methods employed to obtain the model parameters. Parameter and cross section tables are given. C1 ENTE NAZL ENERGIA ATOM,BOLOGNA,ITALY. RP REFFO, G (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 380 EP 388 DI 10.1016/0168-9002(91)90208-8 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800033 ER PT J AU KENNEDY, EJ ALLEY, GT BRITTON, CL SKUBIC, PL GRAY, B WU, A AF KENNEDY, EJ ALLEY, GT BRITTON, CL SKUBIC, PL GRAY, B WU, A TI RADIATION EFFECTS ON JFETS, MOSFETS, AND BIPOLAR-TRANSISTORS, AS RELATED TO SSC CIRCUIT-DESIGN SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Some results of radiation effects on selected junction field-effect transistors, MOS field-effect transistors, and bipolar junction transistors are presented. The evaluation include dc parameters, as well as capacitive variations and noise evaluations. The tests are made at the low current and voltage levels (in particular at currents less-than-or-equal-to 1 mA) that are essential for the low-power regimes required by SSC circuitry. Detailed noise data are presented both before and after 5-Mrad (gamma) total-dose exposure. SPICE radiation models for three high-frequency bipolar processes are compared for a typical charge-sensitive preamplifier. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV OKLAHOMA,DEPT PHYS & ASTRON,NORMAN,OK 73019. RP KENNEDY, EJ (reprint author), UNIV TENNESSEE,DEPT ELECT & COMP ENGN,KNOXVILLE,TN 37996, USA. NR 2 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 1991 VL 307 IS 2-3 BP 452 EP 457 DI 10.1016/0168-9002(91)90217-E PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GJ748 UT WOS:A1991GJ74800042 ER PT J AU LEWIS, MB LEE, EH AF LEWIS, MB LEE, EH TI RESIDUAL-GAS AND ION-BEAM ANALYSIS OF ION-IRRADIATED POLYMERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID BOMBARDMENT AB In order to understand the ion-polymer interactions which lead to improved polymer-surface properties of ion-irradiated polymers, we have measured both the gases evolved from the polymers Teflon and Kapton during irradiation and the change in the composition of Kapton after irradiation. Ion beams of helium, nitrogen and silicon in the energy range 0.2 to 2.0 MeV were used to irradiate the targets. The primary residual gases observed were CF and CF3 from Teflon and H-2, CO, and CO2 from Kapton. Teflon appeared to decompose by fragmentation of its molecular chain. Ion beam analysis of the ion-irradiated Kapton was carried out by Rutherford backscattering (RBS), by elastic recoil detection analysis (ERDA), and by nuclear reaction analysis (NRA). The results from these analyses show that the heavy-ion irradiation creates a complex depth dependence in the composition of the target. Radiolysis and radiation induced chemical reactions during the ion irradiation are discussed. RP LEWIS, MB (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 24 TC 59 Z9 59 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 OCT PY 1991 VL 61 IS 4 BP 457 EP 465 DI 10.1016/0168-583X(91)95323-6 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GP187 UT WOS:A1991GP18700016 ER PT J AU BEILAI, H AF BEILAI, H TI ESTIMATION OF PARTICLE LOSSES DUE TO MULTIPLE-SCATTERING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article AB In experiments with energetic charged particles, multiple scattering by target atoms may cause a significant loss in the number of particles emitted into a given solid angle, d-OMEGA. The total fractional loss of charged particles from multiple scattering in a thin foil preceding the detector is calculated analytically. The numerical results are given in the form of a universal plot. The results show both that a small solid angle of detection and a large beam diameter will produce a serious particle loss, and that the influences of the two factors on particle loss are not the same. C1 NANKAI UNIV,DEPT PHYS,TIANJIN,PEOPLES R CHINA. RP BEILAI, H (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 11 TC 0 Z9 0 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 OCT PY 1991 VL 61 IS 4 BP 522 EP 526 DI 10.1016/0168-583X(91)95332-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GP187 UT WOS:A1991GP18700025 ER PT J AU GREENE, JP THOMAS, GE AF GREENE, JP THOMAS, GE TI EVAPORATION TECHNIQUES FOR PREPARING RARE-EARTH TARGETS USED IN HEAVY-ION NUCLEAR-PHYSICS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 11TH INTERNATIONAL CONF ON THE APPLICATIONS OF ACCELERATORS IN RESEARCH AND INDUSTRY CY NOV 05-08, 1990 CL DENTON, TX AB The preparation techniques for producing targets of rare-earth isotopes depend greatly upon the chemical and physical properties of the particular rare-earth element. In most cases the isotope is supplied in the oxide form requiring a reduction to the metallic form. Collection efficiencies will be discussed. RP GREENE, JP (reprint author), ARGONNE NATL LAB,DIV PHYS,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 12 TC 6 Z9 6 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 OCT PY 1991 VL 61 IS 4 BP 575 EP 579 DI 10.1016/0168-583X(91)95341-A PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA GP187 UT WOS:A1991GP18700034 ER PT J AU SHOLTIS, JA HUFF, DA GRAY, LB KLUG, NP WINCHESTER, RO AF SHOLTIS, JA HUFF, DA GRAY, LB KLUG, NP WINCHESTER, RO TI TECHNICAL NOTE - THE INTERAGENCY NUCLEAR SAFETY REVIEW PANELS EVALUATION OF THE ULYSSES SPACE MISSION SO NUCLEAR SAFETY LA English DT Note AB The October 1990 launch and deployment of the nuclear-powered Ulysses spacecraft from the Space Shuttle Discovery culminated an extensive safety review and evaluation effort by the Interagency Nuclear Safety Review Panel (INSRP). After more than a year of detailed independent review, study, and analysis, the INSRP prepared a Safety Evaluation Report (SER) on the Ulysses mission in accordance with Presidential Directive/National Security Council Memorandum 25. The SER, which included a review of the Ulysses Final Safety Analysis Report (FSAR) and an independent characterization of the mission risks, was used by the National Aeronautics and Space Administration (NASA) in its decision to request launch approval as well as by the Executive Office of the President in arriving at a launch decision based on risk-benefit considerations. This paper provides an overview of the Ulysses mission and the conduct, as well as results, of the INSRP evaluation. Although the mission risk determined by the INSRP in the SER was higher than that characterized by the Ulysses project in the FSAR, both reports indicated that the radiological risks were relatively small. In the final analysis, the SER proved to be supportive of a positive launch decision. The INSRP evaluation process has demonstrated its effectiveness numerous times since the 1960s. In every case it has provided the essential ingredients and perspective to permit an informed launch decision at the highest level of our government. C1 US DOE,WASHINGTON,DC 20585. NATL AERONAUT & SPACE ADM,WASHINGTON,DC. NR 11 TC 1 Z9 1 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 494 EP 501 PG 8 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000003 ER PT J AU HYDER, ML AF HYDER, ML TI THE SEVERE ACCIDENT ANALYSIS PROGRAM FOR THE SAVANNAH RIVER NUCLEAR PRODUCTION REACTORS SO NUCLEAR SAFETY LA English DT Article AB Severe accident phenomena pertinent to the heavy-water-moderated production reactors of the U.S. Department of Energy are being studied in the Severe Accident Analysis Program (SAAP) at the Savannah River Site. The SAAP has sought to define the behavior of the Savannah River reactors in accident scenarios involving significant fuel melting. The goal of the program is to make possible accident analyses of the production reactors that are of comparable quality to those done for power reactors. These large Savannah River reactors differ from power reactors in several important respects: they operate at low temperature and pressure, their fuel is uranium metal alloyed and clad with aluminum, and radioactive releases are contained by a filtered confinement system rather than by static containment. These differences have guided the experimental and calculational development of the SAAP, which also draws where possible on analyses made for other types of reactors. Major experimental research areas in the SAAP have included fuel-melting phenomena, melt relocation and its interactions with water and concrete, fission-product release and mobility, and the response of the confinement system under accident conditions. The MELCOR and SCDAP/RELAP5 code packages, developed for severe accident analyses of commercial power reactors, have also been adapted to the Savannah River reactors under the SAAP. These are already being used in accident analyses. Calculational tools have also been developed for estimating the potential effects of steam explosions. Experimental work is continuing, as is the validation and application of the code packages. RP HYDER, ML (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER LAB,AIKEN,SC, USA. NR 48 TC 1 Z9 1 U1 1 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 502 EP 510 PG 9 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000004 ER PT J AU KISNER, RA AF KISNER, RA TI A FRAMEWORK FOR SELECTING SUITABLE CONTROL TECHNOLOGIES FOR NUCLEAR-POWER-PLANT SYSTEMS SO NUCLEAR SAFETY LA English DT Article AB New concepts continue to emerge for controlling systems, subsystems, and components and for monitoring parameters, characteristics, and vital signs in nuclear power plants. The steady stream of new control theories and the evolving state of control software exacerbates the difficulty of selecting the most appropriate control technology for nuclear power-plant systems. As plant control room operators increase their reliance on computerized systems, the integration of monitoring, diagnostic, and control functions into a uniform and understandable environment becomes imperative. A systematic framework for comparing and evaluating the overall usefulness of control techniques is needed. This article describes nine factors that may be used to evaluate alternative control concepts. These factors relate to a control system's potential effectiveness within the context of the overall environment, including both human and machine components. Although not an in-depth study, this article serves to outline an evaluation framework based on several measures of utility. RP KISNER, RA (reprint author), OAK RIDGE NATL LAB,DIV INSTRUMENTAT & CONTROLS,BOX 2008,OAK RIDGE,TN 37831, USA. NR 31 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 511 EP 520 PG 10 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000005 ER PT J AU WILLIAMS, PM AF WILLIAMS, PM TI CONTAINMENTS FOR GAS-COOLED POWER-REACTORS - HISTORY AND STATUS SO NUCLEAR SAFETY LA English DT Article ID TEMPERATURE AB This article discusses containment design for gas-cooled reactors by surveying the international background and modern practices. Modern gas-cooled reactors are differentiated from earlier designs by their fuel forms, which are either of the ceramically coated particle type being developed by the United States, the Federal Republic of Germany, and Japan or of the stainless-steel-clad, uranium-dioxide pellet type used by the United Kingdom. Early reactor designs and experiences are described to provide support and background for subsequent discussions of modern designs, accident potentials, and radionuclide source terms. Resolution of containment issues is seen to require a careful balance between a mechanistic source-term approach and the traditional "defense-in-depth" requirements that add additional systems and barriers to account for uncertainties and unknowns. Designers and researchers need to strive within economic realities to achieve a degree of completeness and conservatism on the containment design that can be judged satisfactory by regulatory authorities and others. RP WILLIAMS, PM (reprint author), US DOE,WASHINGTON,DC, USA. NR 36 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 521 EP 536 PG 16 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000006 ER PT J AU MUHLHEIM, MD SILVER, EG AF MUHLHEIM, MD SILVER, EG TI ACTIVITIES RELATED TO WASTE AND SPENT FUEL-MANAGEMENT SO NUCLEAR SAFETY LA English DT Article RP MUHLHEIM, MD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 555 EP 566 PG 12 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000009 ER PT J AU SULLIVAN, K GUNTHER, W AF SULLIVAN, K GUNTHER, W TI EFFECTS OF COMPONENT AGING ON THE WESTINGHOUSE CONTROL ROD DRIVE SYSTEM SO NUCLEAR SAFETY LA English DT Article AB An assessment of aging for the Westinghouse pressurized-water-reactor (PWR) control-rod-drive (CRD) system has been completed as part of the U. S. Nuclear Regulatory Commission Nuclear Plant Aging Research (NPAR) Program. This study examined the design, construction, maintenance, and operation of the system to determine its potential for degradation as the plant ages. This article presents selected results from this study. The operating experience data were evaluated to identify the predominant failure modes, causes, and effects. From our evaluation of the data, coupled with an assessment of the materials of construction and the operating environment, we conclude that the Westinghouse CRD system is subject to degradation that, if left unchecked, could affect its safety function as the plant ages. Ways to detect and mitigate the effects of aging are included in this article. The current maintenance for the CRD system at 15 Westinghouse PWRs was obtained through a survey conducted in co-operation with the Electric Power Research Institute and the Nuclear Management and Resources Council. The survey results indicate that some plants have modified the system, replaced components, or expanded preventive maintenance practices. Several of these activities have effectively addressed the aging issue. RP SULLIVAN, K (reprint author), BROOKHAVEN NATL LAB,DEPT NUCL ENERGY,UPTON,NY 11973, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 567 EP 576 PG 10 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000010 ER PT J AU CLETCHER, JW AF CLETCHER, JW TI REACTOR SHUTDOWN EXPERIENCE SO NUCLEAR SAFETY LA English DT Article RP CLETCHER, JW (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 577 EP 579 PG 3 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000011 ER PT J AU MURPHY, GA AF MURPHY, GA TI SELECTED SAFETY-RELATED EVENTS SO NUCLEAR SAFETY LA English DT Article RP MURPHY, GA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 580 EP 581 PG 2 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000012 ER PT J AU MUHLHEIM, MD SILVER, EG AF MUHLHEIM, MD SILVER, EG TI OPERATING UNITED-STATES POWER-REACTORS SO NUCLEAR SAFETY LA English DT Article RP MUHLHEIM, MD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD OCT-DEC PY 1991 VL 32 IS 4 BP 582 EP 595 PG 14 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HW450 UT WOS:A1991HW45000013 ER PT J AU WESTON, LW TODD, JH AF WESTON, LW TODD, JH TI MEASUREMENT OF THE B-10(N, ALPHA-O) B-10(N, ALPHA-GAMMA) RATIO VERSUS NEUTRON ENERGY SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB The ratio of ground-state transitions to excited-state transitions following neutron absorption in B-10 has been measured for the 20- to 1000-keV neutron energy region. Face-to-face silicon surface-barrier detectors were used to detect reactions and measure the total energy of the emitted alpha and lithium particles. The Oak Ridge Electron Linear Accelerator was used as a white neutron source, and time of flight was used to determine the neutron energy. The ratio varied from 0.064 at the lowest energies to 0.72 at 920 keV. The current measurements tend to be smaller than the currently accepted values by 10 to 30% in the 100- to 600-keV energy region. RP WESTON, LW (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 18 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 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD OCT PY 1991 VL 109 IS 2 BP 113 EP 119 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GJ711 UT WOS:A1991GJ71100001 ER PT J AU HENDRICKS, JS PRAEL, RE AF HENDRICKS, JS PRAEL, RE TI MONTE-CARLO NEXT-EVENT ESTIMATES FROM THERMAL COLLISIONS SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB A new approximate method is developed to allow S(alpha,beta) thermal collision contributions to next-event estimators in Monte Carlo calculations. The new technique is applicable to the more general problem of contributions to next-event estimators from any discrete probability distribution. The method is incorporated into the MCNP Monte Carlo radiation transport code. RP HENDRICKS, JS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD OCT PY 1991 VL 109 IS 2 BP 150 EP 157 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GJ711 UT WOS:A1991GJ71100005 ER PT J AU BERKAN, RC UPADHYAYA, BR TSOUKALAS, LH KISNER, RA AF BERKAN, RC UPADHYAYA, BR TSOUKALAS, LH KISNER, RA TI RECONSTRUCTIVE INVERSE DYNAMICS CONTROL AND APPLICATION TO XENON-INDUCED POWER OSCILLATIONS IN PRESSURIZED WATER-REACTORS SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB Axial flux shape control in large pressurized water reactors constitutes one of the most challenging control problems in the nuclear field. In commercial plants, the practical solutions are obtained at the expense of departure from the most economical operational conditions, often due to the difficulties in monitoring xenon-induced oscillations and inadequate control actions. The concept of inverse dynamics in control is introduced as an alternative approach for spatial control. The method is tested through computer simulations using a validated nonlinear model that successfully represents the limit-cycle behavior. Compared with the widely used half-cycling strategy or the proposed optimal control methods in the literature, the use of inverse dynamics for partial-length rod control yields desirable stability characteristics. The return to target axial offset exhibits a smooth transition without any residual flux oscillations between the upper and lower halves of the core. The proposed approach consists of a set of nonlinear algebraic equations for control with single-step solutions. Thus, it is easier to implement compared with iterative or integral techniques. C1 OAK RIDGE NATL LAB,DIV INSTRUMENTAT & CONTROLS,OAK RIDGE,TN 37831. RP BERKAN, RC (reprint author), UNIV TENNESSEE,DEPT NUCL ENGN,KNOXVILLE,TN 37996, USA. NR 12 TC 11 Z9 11 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 OCT PY 1991 VL 109 IS 2 BP 188 EP 199 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GJ711 UT WOS:A1991GJ71100008 ER PT J AU ROCHE, MF LEIBOWITZ, L SETTLE, JL JOHNSON, CE VOGEL, RC RITZMAN, RL AF ROCHE, MF LEIBOWITZ, L SETTLE, JL JOHNSON, CE VOGEL, RC RITZMAN, RL TI VAPORIZATION OF STRONTIUM, BARIUM, LANTHANUM, AND URANIUM FROM MIXTURES OF URANIA, ZIRCONIA, STEEL, AND CONCRETES AT 2150-K AND 2400-K SO NUCLEAR TECHNOLOGY LA English DT Article DE FISSION PRODUCT RELEASE; SOURCE TERMS; REACTOR ACCIDENTS ID OXIDE AB The vaporization of strontium, barium, and lanthanum from mixtures of their oxides with urania, zirconia, and concrete is determined with the objective of understanding the release of these refractory fission products during the core/concrete interaction phase of a degraded core accident. The vaporization of uranium and the total mass vaporized are also determined. Three different concretes having silica contents ranging from 7 to 69 wt% are used to reflect the known range of reactor basemat compositions. In the experiments, the mixtures are vaporized at 2150 or 2400 K into flowing H-2 or He-6 H-2 gas. The total mass of material that was vaporized is determined by weighing the condensates; the masses of individual elements are determined by chemical analyses of the condensates. The phases present in the heated mixtures are inferred from electron probe microanalyses and X-ray diffraction analyses. Equilibrium calculations are performed using SOLGASMIX and a thermodynamic data base containing 112 gaseous and 108 condensed species. The partial molar free energy of oxygen is calculated from the equilibrium oxygen pressure established in the high-temperature reaction zone between the gas and the sample. Using this experimental data, the release to be expected in the molten core/concrete interaction phase of a severe nuclear reactor accident is estimated. The estimated release of strontium, barium, lanthanum, and uranium is < 1% with a basemat concrete of low silica content (7 wt%) and decreases to < 0.01% with a basemat concrete of high silica content (69 wt%). The estimated total mass release is approximately 0.5% with all three concrete types. C1 ELECT POWER RES INST,PALO ALTO,CA 94304. RP ROCHE, MF (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 1991 VL 96 IS 1 BP 96 EP 116 PG 21 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GH113 UT WOS:A1991GH11300009 ER PT J AU BENNETT, RG AF BENNETT, RG TI FINITE-ELEMENT STRESS-ANALYSIS FOR COATED PARTICLE FUEL MODELING UNDER NORMAL OPERATING-CONDITIONS SO NUCLEAR TECHNOLOGY LA English DT Note DE STRESS ANALYSIS; FUEL PARTICLE; MODULAR HIGH-TEMPERATURE GAS-COOLED REACTOR AB Finite element modeling of the stresses in TRISO-coated fuel particles under normal operating conditions is undertaken with the ABAQUS code. Accurate results for the coating layer stresses are obtained with 30 finite elements in the model and approximately 100 time steps through the life of the fuel. When compared to an earlier General Atomics/Forschungszentrum Julich (GA/KFA) computer model of fuel performance, several discrepancies are uncovered in the earlier model. The GA/KFA model underpredicts the stresses in the silicon carbide layer, and the discrepancy increases with fission gas pressure. C1 IDAHO NATL ENGN LAB,ADV REACTOR DESIGN UNIT,IDAHO FAUS,ID. NR 12 TC 8 Z9 8 U1 1 U2 3 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 1991 VL 96 IS 1 BP 117 EP 122 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GH113 UT WOS:A1991GH11300010 ER PT J AU ROBERTS, LE AF ROBERTS, LE TI UPDATED ESTIMATE FOR INCLUSIVE LARGE-MASS MUON PAIR PRODUCTION IN ULTRARELATIVISTIC NUCLEUS-NUCLEUS COLLISIONS FOR COLLIDING BEAMS SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS LA English DT Article ID HIGH-TEMPERATURES; MONTE-CARLO; COLLISIONS; DENSITIES; QUARKS; GLUONS AB For colliding beams of several species of ions we compare thermal to perturbative quantum-chromodynamic contributions for inclusive large-mass muon pair production by using a hydrodynamical model in conjunction with the MIT bag model to estimate the temperatures of the quark-gluon plasma produced by each species. The production of high-energy dimuons with M congruent-to (2 divided-by 4) GeV will be favored energetically by the quark-gluon plasma. C1 ARGONNE NATL LAB, DIV HIGH ENERGY PHYS, ARGONNE, IL 60439 USA. RP ROBERTS, LE (reprint author), LINCOLN UNIV, DEPT PHYS, LINCOLN UNIVERSITY, PA 19352 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 1124-1861 J9 NUOVO CIMENTO A JI Nuovo Cimento Soc. Ital. Fis. A-Nucl. Part. Fields PD OCT PY 1991 VL 104 IS 10 BP 1419 EP 1427 DI 10.1007/BF02817424 PG 9 WC Physics, Particles & Fields SC Physics GA GT152 UT WOS:A1991GT15200001 ER PT J AU SEVER, LE AF SEVER, LE TI PARENTAL RADIATION EXPOSURE AND CHILDRENS HEALTH - ARE THERE EFFECTS ON THE 2ND GENERATION SO OCCUPATIONAL MEDICINE-STATE OF THE ART REVIEWS LA English DT Article AB This paper describes the mechanisms through which parental occupational radiation exposure could affect children's health. It then goes on to review briefly some of the early work on this issue, studies based not on occupational exposures but on the Japanese atomic bomb survivors and on intrauterine x-ray exposure. Most of the discussion focuses on recent studies that have examined risks of childhood cancers and congenital malformations in the offspring of exposed workers, particularly some of the controversy engendered by recent cancer studies. RP SEVER, LE (reprint author), BATTELLE SEATTLE RES CTR,POB C-5395,SEATTLE,WA 98105, USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 SN 0885-114X J9 OCCUP MED JI Occup. Med.-State Art Rev. PD OCT-DEC PY 1991 VL 6 IS 4 BP 613 EP 627 PG 15 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA GN403 UT WOS:A1991GN40300006 PM 1962249 ER PT J AU GILBERT, ES AF GILBERT, ES TI STUDIES OF WORKERS EXPOSED TO LOW-DOSES OF EXTERNAL RADIATION SO OCCUPATIONAL MEDICINE-STATE OF THE ART REVIEWS LA English DT Article AB Currently, several epidemiologic studies of workers who have been exposed occupationally to low levels of radiation are being conducted. They include studies of workers in the United States, Great Britain, and Canada involved in the production of both defense materials and nuclear power. This paper focuses on studies evaluating the possible adverse effects that result from external exposure to radiation. RP GILBERT, ES (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 0 TC 8 Z9 8 U1 0 U2 1 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 SN 0885-114X J9 OCCUP MED JI Occup. Med.-State Art Rev. PD OCT-DEC PY 1991 VL 6 IS 4 BP 665 EP 680 PG 16 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA GN403 UT WOS:A1991GN40300009 PM 1962252 ER PT J AU VOELZ, GL AF VOELZ, GL TI HEALTH CONSIDERATIONS FOR WORKERS EXPOSED TO PLUTONIUM SO OCCUPATIONAL MEDICINE-STATE OF THE ART REVIEWS LA English DT Article AB It is interesting to observe that today the discussions, public concerns, and legal battles over health risks presented by Pu are not only vigorous but also accelerating. Our knowledge of the biochemistry, pathophysiology, dosimetry, and radiobiology of Pu has increased enormously during the intervening 45+ years since the first experiments. For the first time in the history of science and industry, extensive epidemiologic studies are being conducted on the majority of all people in this country who have worked with a material since its introduction and before anyone has had any known acute or chronic illness from exposure to it. RP VOELZ, GL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,OCCUPAT MED GRP,MAIL STOP K404,LOS ALAMOS,NM 87545, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 SN 0885-114X J9 OCCUP MED JI Occup. Med.-State Art Rev. PD OCT-DEC PY 1991 VL 6 IS 4 BP 681 EP 694 PG 14 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA GN403 UT WOS:A1991GN40300010 PM 1962253 ER PT J AU TURKO, BT YATES, GJ AF TURKO, BT YATES, GJ TI ELIMINATION OF ARTIFACTS IN INTERLINE CHARGE-COUPLED DEVICE IMAGERS SO OPTICAL ENGINEERING LA English DT Article DE INTERLINE TRANSFER CHARGE-COUPLED DEVICES; HIGH FRAME RATES; IMAGE ARTIFACTS FROM RADIATION AND SMEAR; ELECTRONIC ELIMINATION OF ARTIFACTS ID CCD AB Charge-coupled devices (CCDs) of interline transfer design are especially useful in imaging at high frame rates. However, their sensitivity to ionization radiation and the reduced effective opacity of vertical charge transfer registers cause undesired image artifacts. Random white spots from the radiation and "ghost" images (or smear) generated in the registers may severely impair the image quality. An electronic method of eliminating these artifacts is described. Special sequences of pulses clock the CCD, quickly dumping the unwanted charge. The fast readout of images, cleared of artifacts, follows immediately. Results obtained with the Fairchild Weston CCD 222 imager are shown. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP TURKO, BT (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV ENGN,BERKELEY,CA 94720, USA. NR 5 TC 3 Z9 3 U1 2 U2 4 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 OCT PY 1991 VL 30 IS 10 BP 1542 EP 1546 DI 10.1117/12.55959 PG 5 WC Optics SC Optics GA GK745 UT WOS:A1991GK74500014 ER PT J AU BUDKER, D COMMINS, ED DEMILLE, D ZOLOTOREV, MS AF BUDKER, D COMMINS, ED DEMILLE, D ZOLOTOREV, MS TI LASER SPECTROSCOPY AND LIFETIME MEASUREMENTS OF DY-I STATES SO OPTICS LETTERS LA English DT Article ID RARE-EARTH ATOMS AB The dysprosium spectrum is studied in the range of 273-284 nm by using pulsed-laser excitation in an atomic beam and fluorescence detection. Lifetimes and branching ratios for the decay to the ground term are determined from the analysis of fluorescence signals for 27 high-lying odd-parity levels. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. RP BUDKER, D (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 10 TC 13 Z9 13 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD OCT 1 PY 1991 VL 16 IS 19 BP 1514 EP 1516 DI 10.1364/OL.16.001514 PG 3 WC Optics SC Optics GA GH880 UT WOS:A1991GH88000020 PM 19777018 ER PT J AU JAHODA, FC FORMAN, PR MASON, BL AF JAHODA, FC FORMAN, PR MASON, BL TI QUANTITATIVE-EVALUATION OF PHASE-CONJUGATE NOVELTY FILTERS SO OPTICS LETTERS LA English DT Article AB A Michelson interferometer whose signal arm is terminated by a self-pumped BaTiO3 phase conjugator records phase-change distributions in times short compared with the conjugator rewrite time that correspond quantitatively to a single (not a double) traversal of the phase disturbance. The proffered explanation, which is experimentally substantiated, also places limitations on the pictorial accuracy of intensity-change novelty filters. RP JAHODA, FC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS D410,LOS ALAMOS,NM 87545, USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD OCT 1 PY 1991 VL 16 IS 19 BP 1532 EP 1534 DI 10.1364/OL.16.001532 PG 3 WC Optics SC Optics GA GH880 UT WOS:A1991GH88000026 PM 19777024 ER PT J AU SRINIVASAN, V HARRIS, LA PADGETT, RA BAER, DR AF SRINIVASAN, V HARRIS, LA PADGETT, RA BAER, DR TI SULFIDATION BEHAVIOR OF FE-25CR-20NI-1.5AL2O3 IN SIMULATED COAL COMBUSTION GASIFICATION ENVIRONMENTS SO OXIDATION OF METALS LA English DT Article DE SULFIDATION; FE-25CR-20NI-1.5AL2O3; OXIDE DISPERSION-STRENGTHENED ALLOY; MIXED GAS CORROSION; COAL COMBUSTION GASIFICATION ID ALLOYS; SCALES; ADHERENCE; OXIDATION; GROWTH AB The effect of minor addition of alpha-Al2O3 dispersoids on the sulfidation behavior of Fe-25Cr-20Ni was investigated over a range of pO2, 1.13 x 10(-20) to 1.18 x 10(-22) atm. at constant pS2 = 1.22 x 10(-8) atm. Fe-25Cr-20Ni and Fe-25Cr-20Ni 1.5Al2O3 with and without preformed oxide scales were exposed to bioxidant gas mixtures H2/H2O/H2S/Ar at 700-degrees-C. Both isothermal and cyclic exposures were included. Scales were characterized by a combination of several surface analytical tools. A remarkable improvement in sulfidation resistance is observed in Fe-25Cr-20Ni-1.5Al2O3 under the conditions investigated here. This is attributed to the ability of the alloy to form and maintain a predominantly Cr2O3 scale with reduced Fe-diffusion and content. Possible scientific reasons for such improvement are discussed. The base alloy, Fe-25Cr-20Ni, fails to develop and retain such a Cr2O3 scale and undergoes sulfidation within a few minutes of exposure. The scale breakdown process by sulfidation is explained qualitatively. Experimental evidence suggests that sulfur in the environment enhances Fe-diffusion and content in the scale. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP SRINIVASAN, V (reprint author), UES INC, 4401 DAYTON XENIA RD, DAYTON, OH 45432 USA. RI Baer, Donald/J-6191-2013 OI Baer, Donald/0000-0003-0875-5961 NR 21 TC 1 Z9 1 U1 0 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0030-770X J9 OXID MET JI Oxid. Met. PD OCT PY 1991 VL 36 IS 3-4 BP 195 EP 219 DI 10.1007/BF00662962 PG 25 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA GL486 UT WOS:A1991GL48600001 ER PT J AU STUMP, DM AF STUMP, DM TI THE ROLE OF SHEAR STRESSES AND SHEAR STRAINS IN TRANSFORMATION-TOUGHENING SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID CERAMICS; MECHANICS; ZIRCONIA AB The effect of shear stresses and shear strains on microstructural development in transformation-toughened materials is studied with a procedure that treats the particles as a distribution of small, circular, transforming spots that surround the tip of a semi-infinite stationary crack. Microstructural simulations were conducted by incrementing a set of remote applied stresses consistent with a mode I K-field on a cracked plane containing untransformed spots. When a critical stress criterion was satisfied at a spot centre, that spot underwent a uniform stress-free transformation strain. Microstructures at crack-growth initiation show that the action of shear strains and the influence of shear stresses have an important effect on the size and shape of the region of transformed spots. The presence of shear can produce transformation zone shapes which are radically different from those predicted by the conventional continuum model of a dilatational strain triggered by a critical level of mean stress. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87544. NR 18 TC 21 Z9 21 U1 2 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD OCT PY 1991 VL 64 IS 4 BP 879 EP 902 PG 24 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA GJ651 UT WOS:A1991GJ65100010 ER PT J AU CHURCHILL, ME PEAK, JG PEAK, MJ AF CHURCHILL, ME PEAK, JG PEAK, MJ TI REPAIR OF NEAR-VISIBLE-LIGHT-INDUCED AND BLUE-LIGHT-INDUCED DNA SINGLE-STRAND BREAKS BY THE CHO CELL-LINES AA8 AND EM9 SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SISTER-CHROMATID EXCHANGE; 2 RADIOSENSITIVE CLONES; NEUTRAL FILTER ELUTION; ACTION SPECTRA; ULTRAVIOLET RADIATIONS; FAR-ULTRAVIOLET; MAMMALIAN-CELLS; INDUCTION; DAMAGE; SITES AB The induction of single-strand breaks (SSB) and the kinetics of SSB repair were measured in two Chinese hamster ovary cell lines irradiated with monochromatic photons of near-visible radiation (405 nm) and blue light (434 nm). The radiosensitive and UV-A-sensitive mutant line EM9 is known to repair SSB induced by ionizing radiation or 365-nm UV-A more slowly than the parent line AA8. At the 10% survival level, EM9 cells were 1.7- and 1.6-fold more sensitive than AA8 cells to 405 and 434 nm radiation, respectively. This sensitivity was not due to differences in induction of SSB because AA8 and EM9 cells accumulated the same number of initial breaks when irradiated at 0.5-degrees-C with either 405 nm (5.9 SSB per MJ/m2) or 434 nm (5.1 SSB per MJ/m2), as measured by alkaline elution. When the cells repaired these SSB at 37-degrees-C in full culture medium, biphasic repair kinetics were observed for both cell lines. In both phases of repair, EM9 cells repaired breaks induced by both wavelengths more slowly than did AA8 cells. The t1/2 values for the repair phases for 405-nm-induced SSB were 3.8 and 150 min for EM9, and 1.5 and 52 min for AA8; the corresponding values for repair of 434 nm breaks were 3.7 and 39 min for EM9, and 2.0 and 30 min for AA8. Because of this slower repair, EM9 cells left more SSB unrepaired after 90 min than did AA8 cells for both wavelengths. The ratio of unrepaired breaks in EM9 cells to that in AA8 cells was 1.4 and 1.7 times higher for 405 and 434 nm radiation, respectively. Thus, the sensitivity of EM9 cells to near-visible and visible light correlates with a deficiency in repairing SSB induced by these wavelengths. These results suggest that DNA damage may be a critical event in visible-light-induced cellular lethality and that an important determinant of the ability of AA8 and EM9 cells to survive visible light irradiation may be their ability to repair DNA strand breaks. RP CHURCHILL, ME (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,MOLEC PHOTOBIOL GRP,9700 S CASS AVE,ARGONNE,IL 60439, USA. FU NCI NIH HHS [R01-CA37848, R01-CA34492] NR 31 TC 21 Z9 21 U1 0 U2 1 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD OCT PY 1991 VL 54 IS 4 BP 639 EP 644 DI 10.1111/j.1751-1097.1991.tb02068.x PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GD934 UT WOS:A1991GD93400020 PM 1796118 ER PT J AU GHOSE, S HASTINGS, JM CHOUDHURY, N CHAPLOT, SL RAO, KR AF GHOSE, S HASTINGS, JM CHOUDHURY, N CHAPLOT, SL RAO, KR TI PHONON-DISPERSION RELATION IN FAYALITE, FE2SIO4 SO PHYSICA B LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON NEUTRON SCATTERING CY JAN 21-25, 1991 CL BOMBAY, INDIA SP US, DEPT ATOM ENERGY ID LATTICE-DYNAMICS; FORSTERITE; MG2SIO4 AB Inelastic neutron scattering measurements and rigid-ion model calculations of phonon dispersion relation in the geophysically important mineral fayalite is reported. The measured SIGMA-4 TA branch is found to be softer in fayalite as compared to that in forsterite Mg2SiO4. The rigid-ion model calculations are in satisfactory agreement with the experimental data. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. BHABHA ATOM RES CTR,DIV SOLID STATE PHYS,BOMBAY 400085,INDIA. RP GHOSE, S (reprint author), UNIV WASHINGTON,MINERAL PHYS GRP,SEATTLE,WA 98195, USA. NR 11 TC 12 Z9 12 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1991 VL 174 IS 1-4 BP 83 EP 86 DI 10.1016/0921-4526(91)90582-Y PG 4 WC Physics, Condensed Matter SC Physics GA GJ931 UT WOS:A1991GJ93100020 ER PT J AU PRICE, DL GHOSE, S CHOUDHURY, N CHAPLOT, SL RAO, KR AF PRICE, DL GHOSE, S CHOUDHURY, N CHAPLOT, SL RAO, KR TI PHONON DENSITY OF STATES IN FAYALITE, FE2SIO4 SO PHYSICA B LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON NEUTRON SCATTERING CY JAN 21-25, 1991 CL BOMBAY, INDIA SP US, DEPT ATOM ENERGY ID INELASTIC NEUTRON-SCATTERING AB Inelastic neutron scattering measurements of phonon spectra from a powder sample of fayalite at various temperatures is reported. The measured spectra have been satisfactorily analyzed on the basis of a lattice dynamical model. The phonon density of states is used to derive the specific heat, which are found to be in good agreement with experimental data. C1 UNIV WASHINGTON HOSP,MINERAL PHYS GRP,SEATTLE,WA 98195. BHABHA ATOM RES CTR,DIV SOLID STATE PHYS,BOMBAY 400085,INDIA. RP PRICE, DL (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013 NR 7 TC 14 Z9 14 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1991 VL 174 IS 1-4 BP 87 EP 90 DI 10.1016/0921-4526(91)90583-Z PG 4 WC Physics, Condensed Matter SC Physics GA GJ931 UT WOS:A1991GJ93100021 ER PT J AU ENDOH, Y YAMADA, K KAKURAI, K MATSUDA, M NAKAJIMA, K BIRGENEAU, RJ KASTNER, MA KEIMER, B SHIRANE, G THURSTON, TR AF ENDOH, Y YAMADA, K KAKURAI, K MATSUDA, M NAKAJIMA, K BIRGENEAU, RJ KASTNER, MA KEIMER, B SHIRANE, G THURSTON, TR TI SPIN CORRELATIONS IN HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICA B LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON NEUTRON SCATTERING CY JAN 21-25, 1991 CL BOMBAY, INDIA SP US, DEPT ATOM ENERGY ID MAGNETIC EXCITATIONS; NEUTRON-SCATTERING; DOPED LA2CUO4; FLUCTUATIONS; ANTIFERROMAGNETS; LA2-XSRXCUO4; BEHAVIOR; STATE; PURE AB Recent neutron magnetic scattering experiments from single crystals of both undoped and doped cuprous "214" oxides are reviewed. The magnetic properties in the undoped crystals are essentially interpreted by the quantum two-dimensional Heisenberg antiferromagnetic model. The three-dimensional long-range order occurs because of small but finite interplanar magnetic coupling plus various anisotropies. The doping of charge modifies the spin correlations significantly as well as the spin fluctuations, which suggests close correlations between the charge and spin degrees of freedom. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP ENDOH, Y (reprint author), TOHOKU UNIV,DEPT PHYS,AOBA KU,SENDAI,MIYAGI 980,JAPAN. RI Yamada, Kazuyoshi/C-2728-2009; Matsuda, Masaaki/A-6902-2016 OI Matsuda, Masaaki/0000-0003-2209-9526 NR 46 TC 6 Z9 6 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1991 VL 174 IS 1-4 BP 330 EP 339 DI 10.1016/0921-4526(91)90625-O PG 10 WC Physics, Condensed Matter SC Physics GA GJ931 UT WOS:A1991GJ93100063 ER PT J AU WEST, CD AF WEST, CD TI AN OVERVIEW OF THE PLANNED ADVANCED NEUTRON-SOURCE FACILITY SO PHYSICA B LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON NEUTRON SCATTERING CY JAN 21-25, 1991 CL BOMBAY, INDIA SP US, DEPT ATOM ENERGY AB The Advanced Neutron Source (ANS), now in the conceptual design stage, will be a new user facility for neutron research, including neutron beam experiments, materials irradiation testing and materials analysis capabilities, and production facilities for transuranic and lighter isotopes. The neutron source is to be the world's highest flux beam reactor and is based on existing reactor technology to minimize safety issues. The preferred fuel, U3Si2, has been tested in operating reactors in the United States, Japan and Europe. The core is cooled, moderated and reflected by heavy water common practice for research reactors. RP WEST, CD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1991 VL 174 IS 1-4 BP 430 EP 437 DI 10.1016/0921-4526(91)90641-Q PG 8 WC Physics, Condensed Matter SC Physics GA GJ931 UT WOS:A1991GJ93100079 ER PT J AU MUKHOPADHYAY, R CARLILE, CJ SILVER, RN AF MUKHOPADHYAY, R CARLILE, CJ SILVER, RN TI APPLICATION OF MAXIMUM-ENTROPY TO NEUTRON TUNNELING SPECTROSCOPY SO PHYSICA B LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON NEUTRON SCATTERING CY JAN 21-25, 1991 CL BOMBAY, INDIA SP US, DEPT ATOM ENERGY AB We demonstrate the maximum entropy method for the deconvolution of high-resolution tunneling data acquired with a quasi-elastic spectrometer. Given a precise characterization of the instrument resolution function, a maximum entropy analysis of lutidine data obtained with the IRIS spectrometer at ISIS results in an effective factor-of-three improvement in resolution. C1 BHABHA ATOM RES CTR,DIV SOLID STATE PHYS,BOMBAY 400085,INDIA. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545. RP MUKHOPADHYAY, R (reprint author), RUTHERFORD APPLETON LAB,ISIS PULSED NEUTRON FACIL,DIDCOT OX11 0QX,OXON,ENGLAND. NR 7 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 1991 VL 174 IS 1-4 BP 546 EP 550 DI 10.1016/0921-4526(91)90655-X PG 5 WC Physics, Condensed Matter SC Physics GA GJ931 UT WOS:A1991GJ93100093 ER PT J AU KIJIMA, N GRONSKY, R XIANG, XD VAREKA, WA ZETTL, A CORKILL, JL COHEN, ML AF KIJIMA, N GRONSKY, R XIANG, XD VAREKA, WA ZETTL, A CORKILL, JL COHEN, ML TI CRYSTAL-STRUCTURE OF STAGE-1 IODINE-INTERCALATED SUPERCONDUCTING IBI2SR2CACU2OX SO PHYSICA C LA English DT Article ID OXIDE AB The crystal structure of stage-1 iodine-intercalated superconducting IBi2Sr2CaCu2Ox has been determined by transmission electron microscopy to belong to the superspace group C111Pma2BARBAR with subcell lattice parameters a = 5.4 angstrom, b = 5.4 angstrom, c = 18.9 angstrom, and a structural modulation wavelength of 26 angstrom. Intercalated iodine atoms alter the atomic stacking across Bi-O layers from the stagered configuration characteristic of superconducting Bi2Sr2CaCu2Ox to a vertically aligned configuration in IBi2Sr2CaCu2Ox. From the atomic spacings apparent in the images, it is concluded that the iodine layers bond to their neighboring Bi-O layers by van der Waals interactions. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP KIJIMA, N (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI,NATL CTR ELECTRON MICROSCOPY,LOS ALAMOS,NM 87545, USA. RI Xiang, Xiaodong/A-9445-2012; Zettl, Alex/O-4925-2016; Xiang, Xiaodong/A-5936-2017 OI Zettl, Alex/0000-0001-6330-136X; NR 9 TC 39 Z9 39 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 OCT 1 PY 1991 VL 181 IS 1-3 BP 18 EP 24 DI 10.1016/0921-4534(91)90329-W PG 7 WC Physics, Applied SC Physics GA GL392 UT WOS:A1991GL39200003 ER PT J AU JIN, S KAMMLOTT, GW TIEFEL, TH KODAS, TT WARD, TL KROEGER, DM AF JIN, S KAMMLOTT, GW TIEFEL, TH KODAS, TT WARD, TL KROEGER, DM TI MICROSTRUCTURE AND PROPERTIES OF THE Y-BA-CU-O SUPERCONDUCTOR WITH SUBMICRON-211 DISPERSIONS SO PHYSICA C LA English DT Article ID CRITICAL CURRENTS; YBA2CU3O7-DELTA AB A fine-scale dispersion of Y2BaCuO5 ("211") particles (approximately 8000 angstrom average diam.) within the YBa2Cu3O7-delta superconductor ("123") has been achieved by local melt-texture processing of off-stoichiometric Y-Ba-Cu-O prepared by the aerosol decomposition technique. The presence of such fine particles significantly reduces the thickness of the superconductor plate to below approximately 7000 angstrom. The plate thickness scales almost linearly with 211 particle size. The observed scaling relationship is most likely caused by the 211 inclusions serving as effective nucleation sites for 123 crystallization as well as restricting the plate coarsening below the peritectic temperature. The submicron-sized 211 particles tend to reduce microcracks and segregation of impurity phases at the plate boundaries, however, their effect on flux pinning appears to be insignificant. C1 UNIV NEW MEXICO,DEPT CHEM ENGN,CTR MICROENGINEERED CERAM,ALBUQUERQUE,NM 87131. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP JIN, S (reprint author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA. NR 12 TC 82 Z9 84 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD OCT 1 PY 1991 VL 181 IS 1-3 BP 57 EP 62 DI 10.1016/0921-4534(91)90335-V PG 6 WC Physics, Applied SC Physics GA GL392 UT WOS:A1991GL39200009 ER PT J AU BURGDORFER, J WANG, J RITCHIE, RH AF BURGDORFER, J WANG, J RITCHIE, RH TI ESTIMATES FOR CLUSTER-IMPACT FUSION YIELDS USING THE FERMI ACCELERATION MAP SO PHYSICA SCRIPTA LA English DT Article AB We study the acceleration of deuterons bouncing forth and back between Ti atoms of the solid target and the heavy-water cluster projectiles impinging on a deuterated TiD surface. The multiple scattering sequence restricted to near head-on collisions closely resembles the Fermi acceleration map. Summation over all iterates of the map provides an estimate (possibly an upper limit) for the collisionally generated preequilibrium high-energy tail of the D distribution. Implications for the recent experimental study on cluster-impact fusion by Beuhler et al. are discussed. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP BURGDORFER, J (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 15 TC 17 Z9 17 U1 0 U2 3 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 OCT PY 1991 VL 44 IS 4 BP 391 EP 394 DI 10.1088/0031-8949/44/4/016 PG 4 WC Physics, Multidisciplinary SC Physics GA GM459 UT WOS:A1991GM45900016 ER PT J AU SCHINS, JM SIEBBELES, LDA LOS, J VANDERZANDE, WJ RYCHLEWSKI, J KOCH, H AF SCHINS, JM SIEBBELES, LDA LOS, J VANDERZANDE, WJ RYCHLEWSKI, J KOCH, H TI BRANCHING RATIOS FOR THE DISSOCIATIVE DECAY OF TRIPLET H-2 SO PHYSICAL REVIEW A LA English DT Article ID SPECTROSCOPY AB A systematic study has been performed on the singly excited n = 3 triplet gerade states of molecular hydrogen using fast-neutral-beam photofragment spectroscopy. These states fluoresce to the triplet 2p states and are analyzed according to the energy released in the subsequent dissociation process. The resulting spectra are compared with theoretical results obtained by solving the coupled nuclear Schrodinger equation. Good overall agreement is reported for both the shape of the spectra and the branching ratios for fluorescence to either one of the triplet 2p states. Rotational and vibrational couplings that affect the n = 3 triplet gerade complex are well described by theory. C1 ADAM MICKIEWICZ UNIV,PL-60780 POZNAN,POLAND. ARGONNE NATL LAB,ARGONNE,IL 60439. RP SCHINS, JM (reprint author), FOM,INST ATOM & MOLEC PHYS,KRUISLAAN 407,1098 SJ AMSTERDAM,NETHERLANDS. RI Siebbeles, Laurens/I-2401-2012; Koch, Henrik/J-2537-2012 OI Siebbeles, Laurens/0000-0002-4812-7495; NR 15 TC 35 Z9 35 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 OCT 1 PY 1991 VL 44 IS 7 BP 4171 EP 4179 DI 10.1103/PhysRevA.44.4171 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400017 ER PT J AU CHEN, MH AF CHEN, MH TI RELATIVISTIC INTERMEDIATE-COUPLING CALCULATIONS OF DIELECTRONIC-RECOMBINATION COEFFICIENTS FOR THE LI ISOELECTRONIC SEQUENCE SO PHYSICAL REVIEW A LA English DT Article ID DIRAC-FOCK CALCULATIONS; BE-LIKE IONS; CROSS-SECTIONS; RATES; IONIZATION; AUGER; AL AB Total dielectronic-recombination rate coefficients for 11 ions with 6 less-than-or-equal-to Z less-than-or-equal-to 54 in the Li isoelectronic sequence have been calculated using the distorted-wave technique and the multiconfiguration Dirac-Fock model. The total rate coefficients for the fine-structure states for ions with Z greater-than-or-equal-to 24 can differ by as much as one order of magnitude at low temperatures due to the effects of relativity and intermediate coupling. Effects of Coster-Kronig transitions on rate coefficients are examined. Results from the present work are compared with previous nonrelativistic Hartree-Fock calculations. RP CHEN, MH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP,LIVERMORE,CA 94550, USA. NR 39 TC 23 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4215 EP 4223 DI 10.1103/PhysRevA.44.4215 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400022 ER PT J AU LENGSFIELD, BH RESCIGNO, TN MCCURDY, CW AF LENGSFIELD, BH RESCIGNO, TN MCCURDY, CW TI ABINITIO STUDY OF LOW-ENERGY ELECTRON-METHANE SCATTERING SO PHYSICAL REVIEW A LA English DT Article ID PARAMETER-FREE MODEL; MOLECULE COLLISIONS; VARIATIONAL CALCULATIONS; ELASTIC-SCATTERING; E-CH4 COLLISIONS; CROSS-SECTIONS; CH4; SWITCHES; MINIMUM AB The complex Kohn method is used to study electron-methane scattering with polarized trial functions at incident energies ranging from 0.2 to 10 eV. A perturbative method, which only requires the construction of Fock operators, is used to generate a set of polarized virtual orbitals. These polarized orbitals are then used to construct a compact ab initio scattering function that produces cross sections that are in excellent agreement with experiments in the region of the Ramsauer-Townsend minimum and at higher energies, where a broad maximum is present in the integral cross section. This is the first ab initio study to accurately characterize low-energy electron-methane scattering. C1 OHIO STATE UNIV,DEPT CHEM,COLUMBUS,OH 43210. RP LENGSFIELD, BH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 37 TC 55 Z9 55 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 OCT 1 PY 1991 VL 44 IS 7 BP 4296 EP 4308 DI 10.1103/PhysRevA.44.4296 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400030 ER PT J AU MILLER, JH MANSON, ST AF MILLER, JH MANSON, ST TI RELATIVISTIC MODEL OF SECONDARY-ELECTRON ENERGY-SPECTRA IN ELECTRON-IMPACT IONIZATION SO PHYSICAL REVIEW A LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; ANALYTIC REPRESENTATION; CHARGED PARTICLES; COLLISIONS; PROTON; HELIUM; MOLECULES; ATOMS; IONS AB A relativistic model for differential electron-impact-ionization cross sections that allows the energy spectrum of secondary electrons to be calculated over a wide range of primary-electron energies is presented. The semiempirical method requires only experimental total ionization cross sections and optical oscillator strengths for the target species of interest, but other information, if available, can be incorporated to make the formulation still more accurate. Results for ionization of helium indicate that the lower limit on primary-electron energy for application of the model is about 100 eV. The simple analytic form of the model facilitates investigation of the regions of the secondary-electron energy spectrum where relativistic effects are important. C1 GEORGIA STATE UNIV, DEPT PHYS & ASTRON, ATLANTA, GA 30303 USA. RP MILLER, JH (reprint author), PACIFIC NW LAB, DEPT BIOL & CHEM, RICHLAND, WA 99352 USA. NR 30 TC 0 Z9 0 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4321 EP 4327 DI 10.1103/PhysRevA.44.4321 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400033 ER PT J AU OREL, AE RESCIGNO, TN LENGSFIELD, BH AF OREL, AE RESCIGNO, TN LENGSFIELD, BH TI DISSOCIATIVE EXCITATION OF HEH+ BY ELECTRON-IMPACT SO PHYSICAL REVIEW A LA English DT Article ID ALGEBRAIC VARIATIONAL CALCULATIONS; CONFIGURATION INTERACTION; MOLECULAR ION; SCATTERING; RECOMBINATION; COLLISIONS; ATOMS AB We report the results of an ab initio variational treatment of electron-impact cross sections for the process e- +HeH+ --> e-+He++H for electron energies between 21 eV, the threshold for excitation of the dissociative 1 3-SIGMA+ state, and 26 eV, corresponding to the excitation energy of the first 1-SIGMA+ excited state. The calculations, which were carried out using a recent modification of the complex Kohn method, employed accurate correlated target wave functions, as well as ab initio optical potentials to incorporate the effect of closed channels. The fixed-nuclei excitation cross sections were found to be dominated by a series of sharp resonance structures. However, when the cross sections are averaged over the Franck-Condon envelope of the ground vibrational state, these sharp features are no longer seen. We conclude that the recent experiments that report structure in the HeH+ dissociation cross section cannot be explained within the context of traditional adiabatic-nuclei theory. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP OREL, AE (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94550, USA. NR 31 TC 36 Z9 36 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4328 EP 4335 DI 10.1103/PhysRevA.44.4328 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400034 ER PT J AU REED, KJ CHEN, MH MOORES, DL AF REED, KJ CHEN, MH MOORES, DL TI EXCITATION-AUTOIONIZATION IN HIGHLY CHARGED SODIUM-LIKE IONS SO PHYSICAL REVIEW A LA English DT Article ID ELECTRON-IMPACT IONIZATION; NA-LIKE IONS; APPROXIMATION; FE-15+; RATES; AUGER; AL2+; SI3+; MG+ AB The effects of excitation-autoionization have been studied for nine sodiumlike ions with 26 less-than-or-equal-to Z less-than-or-equal-to 92. Relativistic-distorted-wave methods were used to calculate cross sections for direct electron-impact ionization of these ions. Relativistic-distorted-wave cross sections were computed for electron-impact excitation of n = 2 electrons to n = 3 levels of the ions, and detailed relativistic Auger rates and radiative rates were calculated in order to obtain the excitation-autoionization cross sections. We investigated the variation of these cross sections along the Na-like isoelectronic sequence. We found that configuration interaction significantly affects some cross sections in ions where level crossings occur for some of the doubly excited intermediate states. C1 UNIV LONDON UNIV COLL, DEPT PHYS & ASTRON, LONDON WC1E 6BT, ENGLAND. RP UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DIV HIGH TEMP PHYS, LIVERMORE, CA 94550 USA. NR 20 TC 16 Z9 16 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4336 EP 4344 DI 10.1103/PhysRevA.44.4336 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400035 ER PT J AU ZHANG, Y REDDY, CB SMITH, RS GOLDEN, DE MUELLER, DW GREGORY, DC AF ZHANG, Y REDDY, CB SMITH, RS GOLDEN, DE MUELLER, DW GREGORY, DC TI MEASUREMENT OF ELECTRON-IMPACT SINGLE-IONIZATION CROSS-SECTIONS OF AR8+ SO PHYSICAL REVIEW A LA English DT Article ID IONS AB A crossed-electron-ion-beam experiment was used to measure the total ionization cross section for Ar8+ in the energy range from 50 to 600 eV. The present results are roughly in agreement with the previous measurements of Defrance et Defrance et al. [Nucl. Instrum. Methods Phys. Res. B 23, 256 (1987)] above 450 eV. However, the present measurements show a significant contribution below the threshold for direct ionization. The present measurements agree with the distorted-wave calculations of Pindzola et al. [Phys. Rev. A 41, 1375 (1990)] when 3% of the incident ion beam is assumed to be in metastable states and excitation autoionization from metastable states is included. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP ZHANG, Y (reprint author), UNIV N TEXAS,DEPT PHYS,DENTON,TX 76203, USA. NR 22 TC 9 Z9 10 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4368 EP 4371 DI 10.1103/PhysRevA.44.4368 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400038 ER PT J AU KELLER, N HEIL, O KEMMLER, J LUCAS, MW MAIER, R ROTHARD, H SELLIN, IA GROENEVELD, KO AF KELLER, N HEIL, O KEMMLER, J LUCAS, MW MAIER, R ROTHARD, H SELLIN, IA GROENEVELD, KO TI CONTINUUM ELECTRONS IN COINCIDENCE WITH THE CHARGE STATE OF TARGET IONS SO PHYSICAL REVIEW A LA English DT Article ID DIFFERENTIAL CROSS-SECTIONS; RARE-GAS COLLISIONS; HE-2+-RARE-GAS COLLISIONS; IONIZATION; SPECTROSCOPY; CUSP AB We have measured the continuum electron yield in coincidence with the charge state of the recoiling target ion for the collision systems He+ --> Ne,Ar (170 less-than-or-equal-to E(p) less-than-or-equal-to 330 keV/u). The target ions were detected with a standard time-of-flight spectrometer employing a pulsed electric field to avoid distorting the trajectory of the continuum electron. Comparing our results with cross sections for single- and multiple-target ionization given by DuBois [Phys. Rev. A 39, 4440 (1989)] we find a similarity in the relative proportions of the recoiling charge states for argon at lower energies, but not for neon. Additionally, the yield of continuum electrons associated with each particular charge state of the recoil target ions falls off more rapidly with increasing projectile energy than might be expected. C1 JW GOETHE UNIV,INST KERNPHYS,W-6000 FRANKFURT 90,GERMANY. UNIV SUSSEX,SCH MATH & PHYS SCI,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP KELLER, N (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. NR 22 TC 0 Z9 0 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4407 EP 4411 DI 10.1103/PhysRevA.44.4407 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400043 ER PT J AU MANSOUR, NB KURTZ, C STEIMLE, TC GOODMAN, GL YOUNG, L SCHOLL, TJ ROSNER, SD HOLT, RA AF MANSOUR, NB KURTZ, C STEIMLE, TC GOODMAN, GL YOUNG, L SCHOLL, TJ ROSNER, SD HOLT, RA TI LASER-RF DOUBLE-RESONANCE STUDY OF N2+ SO PHYSICAL REVIEW A LA English DT Article ID BEAM-MAGNETIC-RESONANCE; FIELD HYPERFINE-STRUCTURE; ELECTRON-SPIN-RESONANCE; COLLINEAR LASER; HIGH-RESOLUTION; NEON MATRICES; SPECTROSCOPY; SPECTRUM; ION; FLUORESCENCE AB We have applied the laser-rf-laser double-resonance method to a molecular ion. Fifty-six hyperfine components of fine-structure transitions (DELTA-J = +/- 1) were measured in rotational levels from N = 1 to 27 of the upsilon" = 1 vibrational level of the X 2SIGMA-g+ ground electronic state of N-14(2)+. In order to fit the data, we required seven molecular constants, corresponding to the following interactions: electron spin-rotation fine structure and its centrifugal distortion, Fermi-contact hyperfine structure (hfs), dipolar hfs and its centrifugal distortion, and electric quadrupole and nuclear spin-rotation hfs. The results are in reasonable agreement with theoretical calculations based upon a Hartree-Fock-Roothaan wave function. C1 UNIV WESTERN ONTARIO,DEPT PHYS,LONDON N6A 3K7,ONTARIO,CANADA. ARIZONA STATE UNIV,DEPT CHEM,TEMPE,AZ 85287. RP MANSOUR, NB (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. RI Holt, Richard/C-9125-2013; Kurtz, Chalres/G-1037-2011; Scholl, Timothy/I-6178-2012 OI Kurtz, Chalres/0000-0003-2606-0864; Scholl, Timothy/0000-0002-0807-363X NR 52 TC 22 Z9 22 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4418 EP 4429 DI 10.1103/PhysRevA.44.4418 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400045 ER PT J AU MAITI, A FALICOV, LM AF MAITI, A FALICOV, LM TI PSEUDOPOTENTIAL CALCULATION OF THE TOTAL ENERGY OF SMALL SODIUM CLUSTERS - CROSSOVER FROM ELECTRONIC CLOSED SHELLS TO GEOMETRICAL-STRUCTURE STABILITY SO PHYSICAL REVIEW A LA English DT Article ID SMALL METAL PARTICLES; COLLECTIVE RESONANCE FREQUENCIES; JELLIUM-BACKGROUND MODEL; SELF-CONSISTENT CALCULATION; ANGULAR-MOMENTUM LCR; DYNAMICAL POLARIZABILITY; PHOTOABSORPTION STRENGTH; MULTIPOLE EXCITATIONS; POTASSIUM CLUSTERS; SURFACE-MODES AB A pseudopotential calculation of the total energy of small sodium clusters is presented. It is based on a local-pseudopotential scheme and local-density correlation and exchange. It includes a spherical distribution of electronic charge and minimizes the energy with respect to the position of the ions. It is found that the most stable clusters are (1) those that correspond to closed electronic shells for clusters with fewer than approximately 100 atoms, and (2) those that correspond to geometrical polyhedral clusters for numbers larger than that. A crossover between electronic-level dominance and geometrical-structure stability, found experimentally for high temperatures at larger numbers, is thus theoretically established. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP MAITI, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 36 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4442 EP 4449 DI 10.1103/PhysRevA.44.4442 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400047 ER PT J AU WALKER, B SAEED, M BREEDEN, T YANG, B DIMAURO, LF AF WALKER, B SAEED, M BREEDEN, T YANG, B DIMAURO, LF TI ANOMALOUS INTENSITY-DEPENDENT VIBRATIONAL DISTRIBUTIONS OF OXYGEN MOLECULES IN A NONRESONANT LASER FIELD - A MOLECULAR PERSPECTIVE SO PHYSICAL REVIEW A LA English DT Article ID MULTIPHOTON IONIZATION; AB-INITIO; PHOTOIONIZATION; AUTOIONIZATION; DISSOCIATION; ABSORPTION; H-2; O2 AB We report on the results of nonlinear ionization and dissociation of gas-phase oxygen molecules in an intense (10(11-13) W/cm2) laser field. The investigations were performed with the second- and third-harmonic wavelengths of two different laser systems; a 50-ps Nd:YLF (where YLF denotes yttrium lithium fluoride) and a 10-ns Nd:YAG (where YAG represents yttrium aluminum garnet). Measurements include energy resolved photoelectron and mass spectroscopy. We report on an interesting observation made with excitation of the neutral with green (approximately 2.3 eV) photons, in which the vibrational distribution of the molecular ion shows a strong intensity dependence. We have analyzed this intensity-dependent behavior to be a result of a complex interplay between different resonant and nonresonant electronic channels, which to first approximation does not require dynamical Stark shifting of states. A model is presented that describes this behavior and results in the determination of the molecular constants for the intermediate states. C1 LOUISIANA STATE UNIV,DEPT PHYS,BATON ROUGE,LA 70803. SUFFOLK CTY COMMUNITY COLL,DEPT PHYS,SELDEN,NY 11784. RP WALKER, B (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Walker, Barry/F-8532-2011 NR 27 TC 6 Z9 6 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4493 EP 4498 DI 10.1103/PhysRevA.44.4493 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400052 ER PT J AU GOLDBERG, P MILONNI, PW SUNDARAM, B AF GOLDBERG, P MILONNI, PW SUNDARAM, B TI THEORY OF THE FUNDAMENTAL LASER LINEWIDTH .2. SO PHYSICAL REVIEW A LA English DT Article ID SEMICONDUCTOR-LASERS; PHASE NOISE AB A recent theory of the fundamental laser linewidth developed by the authors is extended to include the effects of the Henry alpha parameter. The usual (1 + alpha-2) enhancement of the linewidth is shown to be increased for arbitrary output coupling by spatial hole burning. A total enhancement factor is derived that multiplies the Schawlow-Townes linewidth and takes into account line broadening due to amplification of quantum noise as well as that due to phase-amplitude coupling. C1 UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. CUNY COLL STATEN ISL, STATEN ISL, NY 10301 USA. RP UNIV CALIF LOS ALAMOS SCI LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. RI Sundaram, Bala/A-6532-2010 OI Sundaram, Bala/0000-0002-1728-704X NR 11 TC 15 Z9 15 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4556 EP 4563 DI 10.1103/PhysRevA.44.4556 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400059 ER PT J AU NILSEN, J CHANDLER, E AF NILSEN, J CHANDLER, E TI ANALYSIS OF THE RESONANTLY PHOTOPUMPED NA-NE X-RAY-LASER SCHEME SO PHYSICAL REVIEW A LA English DT Article ID POPULATION-INVERSION; PLASMAS; PHOTOEXCITATION; GAIN; LINE; COEFFICIENTS; TITANIUM; IONS; IX AB This paper analyzes the resonantly photopumped Na-Ne x-ray-laser scheme that has been studied experimentally on Z pinches for the last five years. By modeling as an x-ray source the Na Z-pinch output obtained on the Saturn generator experiments at Sandia National Laboratories, the time-dependent properties of the Ne lasant are studied. Our model yields a maximum gain, approximately 0.2 cm-1, with a full width at half maximum duration of 18.5 ns, on the 4f --> 3d transition at 231 angstrom under the conditions of the Saturn experiments. We investigate the effects of varying parameters such as the ion density of the Ne lasant and the linewidth of the Na pump line. The impact of radiation trapping on the gain of the various laser lines is considered in a one-dimensional slab geometry. RP NILSEN, J (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 32 TC 18 Z9 18 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4591 EP 4598 DI 10.1103/PhysRevA.44.4591 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400064 ER PT J AU BEIERSDORFER, P CHEN, MH MACLAREN, S MARRS, RE VOGEL, DA WONG, K ZASADZINSKI, R AF BEIERSDORFER, P CHEN, MH MACLAREN, S MARRS, RE VOGEL, DA WONG, K ZASADZINSKI, R TI MEASUREMENTS OF RADIATIVE BRANCHING RATIOS OF K X-RAY TRANSITIONS IN CR-21+, MN-22+, FE-23+, NI-25+, AND GE-29+ SO PHYSICAL REVIEW A LA English DT Note ID DIELECTRONIC SATELLITE SPECTRA; INNER-SHELL TRANSITIONS; HELIUM-LIKE IONS; LINES; NICKEL; LIFETIMES AB The electron-beam ion trap at Lawrence Livermore National Laboratory is used to excite levels selectively in lithiumlike Cr21+, Mn22+, Fe23+, Ni25+, and Ge29+ that possess two radiative-decay branches in the x-ray regime. High-resolution spectroscopic measurements of the relative x-ray intensities are made to infer the radiative branching ratio. Results are compared with theoretical values and demonstrate the importance of relativity in the determination of level structure and mixing coefficients in configuration-interaction calculations. RP BEIERSDORFER, P (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP PHYS,LIVERMORE,CA 94550, USA. NR 27 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4730 EP 4733 DI 10.1103/PhysRevA.44.4730 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400081 ER PT J AU BOTTCHER, C RHOADESBROWN, MJ STRAYER, MR AF BOTTCHER, C RHOADESBROWN, MJ STRAYER, MR TI APPROXIMATE ANALYTIC FORMULA USED TO ESTIMATE ELECTRON-CAPTURE CROSS-SECTIONS AT RELATIVISTIC ENERGIES SO PHYSICAL REVIEW A LA English DT Letter AB The differences between Baur's approximate formalism [as presented, e.g., in C. A. Bertulani and G. Baur, Phys. Rep. 163, 299 (1988)] and the Feynman-Monte Carlo integration for electron capture in heavy-ion colliders [Rhoades-Brown, Bottcher, and Strayer, Phys. Rev. A 40, 2831 (1989)] is discussed. In particular, the use by Baur of approximate wave functions for the bound electron and continuum positron are highlighted. C1 BROOKHAVEN NATL LAB,RELATIVIST HEAVY ION COLLIDER PROJECT,UPTON,NY 11973. RP BOTTCHER, C (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831, USA. NR 6 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT 1 PY 1991 VL 44 IS 7 BP 4769 EP 4770 DI 10.1103/PhysRevA.44.4769 PG 2 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA GK884 UT WOS:A1991GK88400093 ER PT J AU COLLINS, GW FEARON, EM MAPOLES, ER TSUGAWA, RT SOUERS, PC FEDDERS, PA AF COLLINS, GW FEARON, EM MAPOLES, ER TSUGAWA, RT SOUERS, PC FEDDERS, PA TI J = 1 TO J = 0 D2 CONVERSION IN SOLID D-T SO PHYSICAL REVIEW B LA English DT Article ID HIGH ATOM DENSITIES; RELAXATION; TRITIUM; HYDROGEN AB J = 1 to J = 0 molecular rotational time constants for J = 1 D2 in solid D-T at 1.8 to 14 K have been obtained by analyzing the longitudinal relaxation times T1 of the tritons in the same sample. The inherent time constant in the electric quadrupole theory of T1 is a function of both the J = 1 T2 and J = 1 D2 concentrations. By subtracting out the J = 1 T2 behavior as obtained from pure T2 samples, the J = 1 to J = 0 D2 time constants remain. From 10 to 14 K, the D2 time constants are longer than those for T2 at constant temperature by the ratio of the nuclear magnetic moments. From 1.8 to 5.3 K, the two time constants are identical at about 5 h. A time-constant minimum occurs at about 10 K for both hydrogens. A rate-equation theory of rotational catalysis by free hydrogen atoms created by the tritium radioactivity is presented. C1 WASHINGTON UNIV,DEPT PHYS,ST LOUIS,MO 63130. RP COLLINS, GW (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 21 TC 10 Z9 10 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 6598 EP 6607 DI 10.1103/PhysRevB.44.6598 PG 10 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700003 ER PT J AU PAN, HJ PRUSKI, M GERSTEIN, BC LI, F LANNIN, JS AF PAN, HJ PRUSKI, M GERSTEIN, BC LI, F LANNIN, JS TI LOCAL COORDINATION OF CARBON-ATOMS IN AMORPHOUS-CARBON SO PHYSICAL REVIEW B LA English DT Article AB Amorphous carbon has been studied by C-13 and H-1 NMR with the techniques of static single-pulse excitation, magic-angle spinning, and cross polarization with magic-angle spinning. A spin-lattice relaxation time of 0.7 s was obtained for C-13 by progressive saturation. Two different components are seen in the NMR spectrum of C-13 in the static sample. These were resolved using a tensor fitting routine with Gaussian broadening functions. The downfield component corresponds to "sp2-like" carbon atoms, which comprise 93.6% of the total signal. This component was fit to an axially symmetric shift tensor with sigma parallel-to = -28 ppm, sigma perpendicular-to = 209 ppm, and sigma-BAR = 130 ppm. The remaining upfield component is assigned to "sp3-like" carbon atoms. These were fit to a symmetric shift tensor with sigma-BAR = 62 ppm. The concentration of the dangling bonds, as inferred from spin counting by ESR, is about 2 x 10(20) cm-3. About two thirds of the carbon atoms are not seen in the static NMR measurement because of the high concentration of the unpaired electrons, which leads to severe inhomogeneous line broadening. These carbon atoms are detected under magic-angle spinning by the sidebands, which spread over a range of 2000 ppm. The first moment is located at 130 (+/- 5) ppm. The upper limit of the fraction of hydrogenated carbon is estimated to be 1.5%. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. RP PAN, HJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,INST PHYS RES & TECHNOL,AMES,IA 50011, USA. NR 12 TC 77 Z9 78 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 6741 EP 6745 DI 10.1103/PhysRevB.44.6741 PG 5 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700018 ER PT J AU SEVERING, A THOMPSON, JD CANFIELD, PC FISK, Z RISEBOROUGH, P AF SEVERING, A THOMPSON, JD CANFIELD, PC FISK, Z RISEBOROUGH, P TI GAP IN THE MAGNETIC EXCITATION SPECTRUM OF CE3BI4PT3 SO PHYSICAL REVIEW B LA English DT Article ID INELASTIC NEUTRON-SCATTERING; CRYSTAL-FIELD SPECTROSCOPY; SPIN DYNAMICS; HYBRIDIZATION GAP; MIXED-VALENCE; TRANSITION; SYSTEMS; ENERGY AB Static-susceptibility and thermal-expansion measurements indicate that Ce3Bi4Pt3 is mixed-valent-like, whereas transport measurements reveal a gap of DELTA = 5 meV in the electronic excitation spectrum. We report the magnetic response of Ce3Bi4Pt3, at temperatures between 2 and 150 K, determined with incident neutron energies of 3.1, 17, and 69 meV. The isostructural, nonmagnetic reference compound La3Bi4Pt3 was also studied at the same temperatures and energies so that phonon contributions could be subtracted accurately. At 2 K, a gap DELTA-m = 12 meV is present in the magnetic excitation spectrum: the 3.1-, 17-, and 69-meV data consistently show that the magnetic intensity is zero for energy transfers less than 12 meV, rises sharply between 12 and 20 meV, and falls off smoothly beyond. Above 50 K, the gap in the spin-spin correlation function starts to fill. The neutron results reproduce the temperature dependence of the bulk susceptibility. The relationship between these and other measurements will be discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. POLYTECH INST NEW YORK,BROOKLYN,NY 11201. RP SEVERING, A (reprint author), INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. RI Riseborough, Peter/D-4689-2011; Canfield, Paul/H-2698-2014 NR 26 TC 113 Z9 113 U1 2 U2 15 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 6832 EP 6837 DI 10.1103/PhysRevB.44.6832 PG 6 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700031 ER PT J AU COFFEY, MW CLEM, JR AF COFFEY, MW CLEM, JR TI VORTEX INERTIAL MASS FOR A DISCRETE TYPE-II SUPERCONDUCTOR SO PHYSICAL REVIEW B LA English DT Article ID UPPER CRITICAL-FIELD; ORGANIC SUPERCONDUCTOR; DIMENSIONAL CROSSOVER; ANGULAR-DEPENDENCE; SOLITONS; PERTURBATIONS; ANISOTROPY; DYNAMICS; EQUATION; MOTION AB The inertial mass per unit length of vortex in a discrete type-II superconductor is found. Using a Josephson-coupled-layer model, the expression for the inertial mass per unit length for a continuous type-II superconductor is continued from high temperatures (near the transition temperature T(c)) to zero absolute temperature for the case that the vortex is oriented parallel to the layers. The possible application of the vortex inertial mass in studies of microwave and infrared response is discussed. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP COFFEY, MW (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 55 TC 51 Z9 51 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 6903 EP 6908 DI 10.1103/PhysRevB.44.6903 PG 6 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700040 ER PT J AU YU, RC WILLIAMS, JM WANG, HH THOMPSON, JE KINI, AM CARLSON, KD REN, J WHANGBO, MH CHAIKIN, PM AF YU, RC WILLIAMS, JM WANG, HH THOMPSON, JE KINI, AM CARLSON, KD REN, J WHANGBO, MH CHAIKIN, PM TI ANISOTROPIC THERMOPOWER OF THE ORGANIC SUPERCONDUCTOR KAPPA-(BEDT-TTF)2CU[N(CN)2]BR SO PHYSICAL REVIEW B LA English DT Article ID AMBIENT-PRESSURE; BEDT-TTF; BEHAVIOR; 10-K AB The thermopower of the organic superconductor kappa-(BEDT-TTF)2Cu[N(CN)2]Br single crystals has been measured in two crystallographic directions a and c within the most conducting organic donor molecule plane. [Here BEDT-TTF represents bis(ethylenethio)-tetrathiafulvalene.] While the thermopower in the a direction is positive, the thermopower in the c direction is negative. The drastic anisotropy in thermopower reveals that the carriers in the a direction are holelike, whereas the carriers in the c direction are electronlike. A calculation based on the tight-binding electronic band structure is able to describe the temperature dependence of the anisotropic thermopower, but with a much reduced band dispersion. C1 UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. RP YU, RC (reprint author), UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801, USA. RI Kini, Aravinda/F-4467-2012 NR 17 TC 35 Z9 35 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 OCT 1 PY 1991 VL 44 IS 13 BP 6932 EP 6936 DI 10.1103/PhysRevB.44.6932 PG 5 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700045 ER PT J AU MOODENBAUGH, AR YANG, CY ZHU, YM SABATINI, RL FISCHER, DA XU, YW SUENAGA, M AF MOODENBAUGH, AR YANG, CY ZHU, YM SABATINI, RL FISCHER, DA XU, YW SUENAGA, M TI PROPERTIES OF REDUCED THEN REOXIDIZED YBA2(CU1-XFEX)3CUO7-DELTA SO PHYSICAL REVIEW B LA English DT Article ID X-RAY ABSORPTION; HIGH-TC SUPERCONDUCTORS; MOSSBAUER-SPECTROSCOPY; ELECTRON-MICROSCOPY; THERMAL TREATMENTS; FE; CU; YBA2(CU1-XFEX)3O7-DELTA; ORDER; PHASE AB We have investigated YBa2(Cu1-xMx)3O7-delta (1:2:3) (M = Fe, with preliminary results for Co and Al) prepared using three different heat treatments. Standard samples were prepared using sintering temperatures up to 960-degrees-C, followed by slow cooling in oxygen. Oxygen was removed by heating the standard samples in flowing argon near 830-degrees-C, the resulting specimens being called "reduced". Reoxidized samples, in turn, were prepared from reduced samples that were heated in flowing oxygen near 400-degrees-C. The Fe content of selected standard, reduced, and reoxidized samples was determined by electron microprobe. Transmission electron microscopy and x-ray diffraction for reoxidized 1:2:3 M = Fe are consistent with an orthorhombic phase extending to x greater-than-or-equal-to 0.12. Superconducting transition temperatures as measured magnetically are similar for standard and reoxidized cases (except M = Al). X-ray-absorption measurements were performed on samples M = Fe at the Fe K edge to probe the Fe near-neighbor environment. Our analysis suggests that Fe atoms remain in the chain layer regardless of heat treatment. This result is discussed in terms of proposed models involving migration of Fe, clustering in the Cu-O chain layer, and/or movement of Fe to the CuO2 plane layer. Preliminary oxygen K-edge studies utilizing fluorescence yield were used to investigate oxygen electronic structure. C1 AT&T BELL LABS,HOLMDEL,NJ 07733. RP MOODENBAUGH, AR (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV MAT SCI,UPTON,NY 11973, USA. OI Moodenbaugh, Arnold/0000-0002-3415-6762 NR 41 TC 19 Z9 19 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 6991 EP 6998 DI 10.1103/PhysRevB.44.6991 PG 8 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700053 ER PT J AU TAN, ZQ BUDNICK, JI LUO, S CHEN, WQ CHEONG, SW COOPER, AS CANFIELD, PC FISK, Z AF TAN, ZQ BUDNICK, JI LUO, S CHEN, WQ CHEONG, SW COOPER, AS CANFIELD, PC FISK, Z TI X-RAY-ABSORPTION STUDIES OF CATION ORDERING AND VALENCE IN THE T-STAR-PHASE LA2-X-YRXSRYCUO4 (R = SM, EU, GD, TB, AND DY) SO PHYSICAL REVIEW B LA English DT Article ID NEAR-EDGE STRUCTURE; CU-O SYSTEM; SUPERCONDUCTIVITY; OXYGEN; SR; STOICHIOMETRY; LA2-XSRXCUO4; OXIDES; 30-K AB X-ray-absorption measurements have been made at the lanthanide L edges, Sr and Cu K edges in the T*-phase La2-x-yRxSryCuO4 compounds with R = Sm, Eu, Gd, Tb, and Dy. The La and rare-earth x-ray-absorption near-edge (XANES) data and the extended x-ray-absorption fine-structure data both clearly indicate that the R and La ions selectively enter the M' site and M site, respectively. The degree of this site ordering is nearly perfect and is similar for the Sm, Eu, Gd, Tb, and Dy members of this family. The L3 XANES data show that the La, Sm, Eu, Gd, and Dy are trivalent in these compounds, but about 20% of the Tb ions are tetravalent in the Tb material. The Cu K-edge XANES spectra are consistent with a divalent state for copper, and are essentially identical for the as-prepared nonsuperconducting samples and the high-pressure oxygenated superconducting counterparts. This indirectly suggests that the hole carrier in the T*-phase superconductors is largely associated with oxygen atoms as in La1.85Sr0.15CuO4. Based on the results of cation-ordering, cation-valence, and oxygen-content measurements, the superconducting behavior of Sm, Em, and Gd T* phases and the lack of superconductivity in the Tb and Dy compounds are discussed. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. UNIV CONNECTICUT,INST MAT SCI,STORRS,CT 06269. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP TAN, ZQ (reprint author), UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06269, USA. RI Canfield, Paul/H-2698-2014 NR 35 TC 23 Z9 23 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7008 EP 7017 DI 10.1103/PhysRevB.44.7008 PG 10 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700055 ER PT J AU OTT, HR FELDER, E FISK, Z HEFFNER, RH SMITH, JL AF OTT, HR FELDER, E FISK, Z HEFFNER, RH SMITH, JL TI INFLUENCE OF BORON IMPURITIES ON THE SUPERCONDUCTING PHASE-TRANSITION OF U1-XTHXBE13 SO PHYSICAL REVIEW B LA English DT Note ID UBE13; DIAGRAM AB It is demonstrated that weak boron doping of UBe13 drastically alters the temperature dependence of the specific heat just above and also below the superconducting transition. A strong enhancement of the anomaly at T(c) and distinct deviations from mean-field behavior are the most significant features. The influence of small amounts of boron replacing Be in thorium-doped UBe13 is shown to depend on the concentration of Th impurities. Excessive specific heat well below T(c) in these compounds indicates considerable variation of the electronic spectrum even at very low temperatures. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP OTT, HR (reprint author), SWISS FED INST TECHNOL,FESTKORPERPHYS LAB,CH-8093 ZURICH,SWITZERLAND. NR 10 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7081 EP 7084 DI 10.1103/PhysRevB.44.7081 PG 4 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700070 ER PT J AU BUDHANI, RC LESYNA, L DIMARZIO, D WIESMANN, H WILLIAMS, GP AF BUDHANI, RC LESYNA, L DIMARZIO, D WIESMANN, H WILLIAMS, GP TI ELECTRODYNAMICS OF YBA2CU3O7 FILMS DEDUCED FROM SUBMILLIMETER SYNCHROTRON-RADIATION TRANSMITTANCE MEASUREMENTS SO PHYSICAL REVIEW B LA English DT Note ID MAGNETIC PENETRATION DEPTH; HIGH-TC SUPERCONDUCTOR; TEMPERATURE-DEPENDENCE; SINGLE-CRYSTALS; CU-O; GAP; TRANSMISSION AB Transmission measurements on YBa2Cu3O7 films in the spectral range 25 to 100 cm-1 have been performed using synchrotron radiation. In the normal state, the classical Drude conductivity function successfully explains the rise in transmission with frequency. The spectra below T(c) show a strong supercurrent screening of the infrared field. A temperature-dependent penetration depth is calculated from the transmission spectra using the local-limit-response kernel and a quasiparticle conductivity rising as (T/T(c))4. Depending on the film quality, the zero-temperature penetration depth varies from 234 to 340 nm. C1 GRUMMAN AEROSP CORP,GRUMMAN CORP RES CTR,BETHPAGE,NY 11714. RP BUDHANI, RC (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 27 TC 4 Z9 4 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7087 EP 7090 DI 10.1103/PhysRevB.44.7087 PG 4 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700072 ER PT J AU JOYNT, R KWOK, WK CRABTREE, GW HINKS, DG DELONG, L AF JOYNT, R KWOK, WK CRABTREE, GW HINKS, DG DELONG, L TI COMMENT ON SHAPE OF THE UPPER-CRITICAL-FIELD CURVES IN URU2SI2 - EVIDENCE FOR ANISOTROPIC PAIRING - REPLY SO PHYSICAL REVIEW B LA English DT Letter AB We present an alternate interpretation to the comments by P. Thalmeier [preceding paper, Phys. Rev. B 44, 7120 (1991)] based on the assumption that the antiferromagnetic transition is a secondary effect of some other phase transition at T(N) [C. M. Varma (unpublished); see also Palstra et al., Phys. Rev. Lett. 55, 2727 (1985)]. This view is motivated by the observation that the ordered moment in URu2Si2 is very small (approximately 0.02-mu-B) and similar to the ordered moment in UPt3, another heavy-fermion system, and yet the specific-heat anomaly is at least 2 orders of magnitude larger in URu2Si2 than in UPt3. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506. RP JOYNT, R (reprint author), UNIV WISCONSIN,DEPT PHYS,1150 UNIV AVE,MADISON,WI 53706, USA. NR 5 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7122 EP 7123 DI 10.1103/PhysRevB.44.7122 PG 2 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700083 ER PT J AU NIYAZ, P SCALETTAR, RT FONG, CY BATROUNI, GG AF NIYAZ, P SCALETTAR, RT FONG, CY BATROUNI, GG TI GROUND-STATE PHASE-DIAGRAM OF AN INTERACTING BOSE MODEL WITH NEAR-NEIGHBOR REPULSION SO PHYSICAL REVIEW B LA English DT Note ID MONTE-CARLO SIMULATIONS; SYSTEMS; SUPERCONDUCTORS; LOCALIZATION; TRANSITION AB We study the ground-state phase diagram of a one-dimensional lattice model of interacting bosons at commensurate filling. When the ratio of interaction strengths to bandwidth is small, the bosons condense into a superfluid phase. For large on-site repulsion, there is a phase transition to a localized Mott phase where the gap DELTA is nonzero and the Fourier transform at zero momentum of the density-density correlation function S(q = 0) diverges. For large intersite repulsion, S(q = pi) diverges first. By examining the superfluid density rho-s, in addition to the gap and S(q), we obtain a complete characterization of the phase diagram. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP NIYAZ, P (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. RI Batrouni, George/A-9318-2009 NR 21 TC 47 Z9 47 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7143 EP 7146 DI 10.1103/PhysRevB.44.7143 PG 4 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700089 ER PT J AU LIN, HQ AF LIN, HQ TI GROUND-STATE PROPERTIES OF THE 2-DIMENSIONAL HUBBARD-MODEL SO PHYSICAL REVIEW B LA English DT Note ID T-J MODEL; ONE HOLE; SUPERCONDUCTIVITY; ANTIFERROMAGNET; EXCITATIONS; SYSTEMS AB Using all appropriate symmetries for a two-dimensional square system, we have been able to diagonalize exactly the Hubbard Hamiltonian on the 4 x 4 and 18-site lattices. We calculate the ground-state energies, hole-hole interactions, and various correlation functions as functions of the Coulomb repulsion U and band filling, and compare the Hubbard-model results with those obtained from the t-J and strong-coupling models. RP LIN, HQ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,MS-B258,LOS ALAMOS,NM 87545, USA. NR 26 TC 24 Z9 24 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 13 BP 7151 EP 7154 DI 10.1103/PhysRevB.44.7151 PG 4 WC Physics, Condensed Matter SC Physics GA GH807 UT WOS:A1991GH80700091 ER PT J AU PRICE, DL SABOUNGI, ML AF PRICE, DL SABOUNGI, ML TI MELTING IN ALKALI-METAL LEAD ALLOYS - KPB AND CSPB SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-DYNAMICS; HEAT-CAPACITY; LIQUID; SCATTERING; NAPB; RBPB AB Inelastic neutron-scattering measurements have been made on KPb and CsPb alloys at various temperatures in the solid and liquid states. In the thermodynamic data CsPb exhibits two transitions near the melting point at 869 and 920 K. In the intermediate phase, quasielastic broadening is observed, indicating that the phase is a plastic crystal characterized by rapid reorientations of structural units. The results are well reproduced by a simple model describing independent jump reorientations of Cs4Pb4 units between the four orientations found in the crystal at room temperature. KPb on the other hand has a single melting transition at 862 K, and no quasielastic broadening is observed below this temperature, indicating that translational and orientational order disappear simultaneously. The model for jump reorientations in CsPb also explains previous neutron-diffraction results for the intermediate phase. RP PRICE, DL (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 23 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7289 EP 7296 DI 10.1103/PhysRevB.44.7289 PG 8 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800014 ER PT J AU GHOSH, K FUCHS, R AF GHOSH, K FUCHS, R TI CRITICAL-BEHAVIOR IN THE DIELECTRIC-PROPERTIES OF RANDOM SELF-SIMILAR COMPOSITES SO PHYSICAL REVIEW B LA English DT Article ID SEDIMENTARY-ROCKS; POROUS-MEDIA; PERCOLATION; CONSTANT; MODEL; CONDUCTION; TRANSITION; THRESHOLD AB A theory for the dielectric properties of self-similar composite media is presented, in which inclusions of one component are introduced recursively into a second component. The spectral-representation formalism, which gives a material-independent description of the recursive process, is used. General expressions are derived for critical exponents that describe the behavior of the dc conductivity, the static dielectric constant, and limits of the spectral function near the percolation threshold. The critical exponents depend on the form of the average dielectric function used at each stage of the recursive procedure. The Maxwell-Garnett and Bruggeman forms of this average dielectric function are chosen as examples. Applications of the theory to some dielectric properties of brine-filled porous rocks are discussed. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP GHOSH, K (reprint author), JACKSON STATE UNIV,INST PHYS & ATMOSPHER SCI,JACKSON,MS 39217, USA. NR 40 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7330 EP 7343 DI 10.1103/PhysRevB.44.7330 PG 14 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800020 ER PT J AU KLEMM, RA LIU, SH AF KLEMM, RA LIU, SH TI INTRALAYER-VERSUS-INTERLAYER PAIRING IN THE COPPER-OXIDE SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; UPPER CRITICAL-FIELD; HIGH-TEMPERATURE SUPERCONDUCTORS; YBA2CU3O7-DELTA SINGLE-CRYSTALS; BA-CU-O; ENERGY-GAP; LAYERED SUPERCONDUCTORS; MAGNETIC-FIELD; ELECTRONIC-STRUCTURE; SPIN SUSCEPTIBILITY AB We have investigated the competing roles of intralayer s-wave and interlayer BCS-like pairing in determining the c-axis versus ab-plane energy-gap anisotropy in layered superconductors with N = 1,2 conducting planes per unit-cell edge s. For N = 1, intralayer s-wave pairing leads to a conventional order parameter (OP) DELTA-0 with a transition temperature (T(c)) value T(c0) and isotropic energy gap 2\DELTA-0\. For interlayer pairing, the four-vector gap function DELTA approximately 3(k(z)) contains a singlet OP-DELTA-s and a vector triplet OP-DELTA-t, with corresponding normalized gap functions square-root 2 cosk(z)s and square-root 2 sink(z)s. Since DELTA-s and DELTA-t have identical T(c) values (T(cs) = T(ct)), the free energy is minimized when \DELTA-s\ = \DELTA-t\, and the resulting gap 2\DELTA\ is found to be isotropic. However, 2\DELTA\ is completely incompatible with 2\DELTA-0\. For N = 2, there are two intralayer pairing OP's DELTA-0 and DELTA-1, and two interlayer four-vector gap functions-DELTA approximately 3(k(z)) and DELTA approximately 2(k(z)), all of which could contribute to measurable quantities in the Gaussian-fluctuation regime above the highest T(c) value. However, interband pair breaking causes DELTA-1 and DELTA approximately 2 to vanish below the maximum T(c) value. Of the two singlet OP's in DELTA approximately 3(k(z)), the OP-DELTA-s has the higher T(c) value, T(cs), and the second singlet OP can be neglected. The triplet OP-DELTA-t has the T(c) value T(ct) less-than-or-equal-to T(cs). For T(c0) > T(cs), the gap is just 2\DELTA-0\. For T(c0) < T(ct), DELTA-0 = 0 and the gap 2\DELTA(k(z), T)\ is anisotropic. There are two regions of the parameters with different gap-anisotropy behavior. In region I, the gap is always nodeless, and is nearly pure singlet for weak coupling. In region II, the gap has a pair of nodes near to T(cs), but is nodeless at low T, as \DELTA-t\ not-equal 0. For T(cs) > T(c0) > T(ct), the gap 2\DELTA(k(z), T)\ is anisotropic, nodeless at low T, and could on rare occasions involve DELTA-0 not-equal 0, in addition to DELTA-s not-equal 0. In any event, the gap is the same on both of the quasiparticle bands. Our results are discussed in terms of recent far-infrared-reflectance, Raman-scattering, and point-contact-tunneling experiments. Additional experiments to clarify the c-axis versus ab-plane gap anisotropy and the microscopic pairing mechanism are suggested. C1 OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. NR 94 TC 48 Z9 48 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 OCT 1 PY 1991 VL 44 IS 14 BP 7526 EP 7545 DI 10.1103/PhysRevB.44.7526 PG 20 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800044 ER PT J AU KIM, DH MILLER, DJ SMITH, JC HOLOBOFF, RA AF KIM, DH MILLER, DJ SMITH, JC HOLOBOFF, RA TI EFFECTS OF MICROSTRUCTURE ON FLUX PINNING IN EPITAXIAL YBA2CU3OX FILMS SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; MAGNETIC-FIELDS; TWIN BOUNDARIES; MIXED STATE; DISSIPATION; CRYSTALS; MOTION; TC AB The role of microstructure on flux pinning in c-axis-oriented epitaxial YBa2Cu3Ox films grown on LaAlO3 and SrTiO3 has been studied. For a magnetic field parallel to the Cu-O planes, the resistivity and critical current density J(c) have been measured as a function of the angle-theta between the applied field and the direction of the transport current. In addition to a Lorentz-force-independent resistivity, the Lorentz-force-dependent component showed several broad deviations from sin2-theta when a field was aligned parallel to certain microstructural features which vary with the film thickness and substrate material. These features were identified by transmission-electron-microscopy analysis. For films of 5000 angstrom thickness on LaAlO3, resistivity dips were observed for a field applied parallel to the substrate twin boundaries or along misoriented a-axis grains. In thinner films of 900 angstrom thickness also on LaAlO3 in which a-axis grains were negligible, we observed dips corresponding to the orientation of substrate twin boundaries only. For thin films on SrTiO3 in which substrate twins are absent, resistivity dips corresponding to the direction of twin boundaries in the film and, perhaps, interfacial dislocations were observed. Overall, such dips decreased with increasing transport current density and became negligible in J(c) measurements. C1 WESTINGHOUSE ELECT CORP,CTR SCI & TECHNOL,PITTSBURGH,PA 15235. RP KIM, DH (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 20 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7607 EP 7613 DI 10.1103/PhysRevB.44.7607 PG 7 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800051 ER PT J AU MCHENRY, ME SIMIZU, S LESSURE, H MALEY, MP COULTER, JY TANAKA, I KOJIMA, H AF MCHENRY, ME SIMIZU, S LESSURE, H MALEY, MP COULTER, JY TANAKA, I KOJIMA, H TI DEPENDENCE OF THE FLUX-CREEP ACTIVATION-ENERGY ON THE MAGNETIZATION CURRENT FOR A LA1.86SR0.14CUO4 SINGLE-CRYSTAL SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; CRITICAL CURRENT-DENSITY; HIGH-TC SUPERCONDUCTORS; RELAXATION; YBA2CU3O7-X; DECAY AB Magnetic relaxation and hysteresis studies have been performed for a c-axis-oriented single crystal of La1.86Sr0.14CuO4. We demonstrate that the effective activation energy for flux creep, U(eff), is a strongly nonlinear function of the current density J (as given by the irreversible magnetization). For fixed fields of 0.5, 1.0, 2.0, and 3.0 T and temperatures between 4 and 15 K (as consistent with full field penetration of the sample), U(eff)(J) is seen to vary approximately logarithmically with J. A scaling relationship, U(eff)(J) = [-U1g(T)/H(n)]ln(J/J(c)), is shown to be obeyed for this crystal with n congruent-to 0.9 (H in T), U1 congruent-to 180k(B), and J(c)(1 T) congruent-to 3.2 x 10(5) A/cm2. Several functional forms of g (T) have been explored and shown to give reasonable fits if monotonically decreasing in temperature over the range where flux creep is observed. We also explore the ramifications of this functional dependence in explaining an observed exponential temperature dependence of the hysterically determined critical current density. Finally, we show that comparison of the temperature dependence of logarithmic relaxation rate A = dM/d ln(t) and the derivative of the magnetization with respect to ln(T) at fixed time, dM0/d ln(T), can be used to set a scale of the attempt frequency for flux motion consistent with the other measurements. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. YAMANASHI UNIV,INST INORGAN SYNTH,KOFU,YAMANASHI 400,JAPAN. RP MCHENRY, ME (reprint author), CARNEGIE MELLON UNIV,DEPT MET ENGN & MAT SCI,PITTSBURGH,PA 15213, USA. RI McHenry, Michael/B-8936-2009; Tanaka, Isao/D-1519-2012 NR 28 TC 149 Z9 149 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7614 EP 7624 DI 10.1103/PhysRevB.44.7614 PG 11 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800052 ER PT J AU SHI, DL SALEMSUGUI, S AF SHI, DL SALEMSUGUI, S TI MAGNETIC-RELAXATION IN YBA2CU3OX SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; SELF-ORGANIZED CRITICALITY; CRITICAL CURRENT-DENSITY; FLUX CREEP; II SUPERCONDUCTORS; MELT-GROWTH; IRREVERSIBILITY; YBACUO; POWDER; STATE AB We measured the magnetic relaxation in the high-T(c) superconductor YBa2Cu3OIx) at a wide range of temperatures and applied fields. The relaxation measurements were performed on single-crystal, melt-textured, and sintered samples. We found that magnetic relaxation depends strongly on the microstructure and crystal orientation. By combining Bean's critical-state model and the Anderson-Kim flux-creep theory, we used a previously developed expression to interpret the magnetic relaxation behavior and the dependence of the field penetration on the sample size. We also investigated the relationship between the flux-creep-activation pinning energy and the decay of the persistent current in the single-crystal sample of YBa2Cu3Ox. RP SHI, DL (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 38 TC 52 Z9 53 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7647 EP 7653 DI 10.1103/PhysRevB.44.7647 PG 7 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800055 ER PT J AU MOROSIN, B KWEI, GH SCHIRBER, JE VOIGT, JA VENTURINI, EL GOLDSTONE, JA AF MOROSIN, B KWEI, GH SCHIRBER, JE VOIGT, JA VENTURINI, EL GOLDSTONE, JA TI SUPERCONDUCTING SUPEROXYGENATED CUPRATES - SEARCH FOR PHASE-SEPARATION IN LA1.84SR0.16CUO4+DELTA SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-DIFFRACTION; CRYSTAL-STRUCTURE; OXYGEN DEFECT; LA2CUO4+DELTA; LA2CUO4.032; TEMPERATURE; REFINEMENT; TRANSITION AB We have studied high-pressure (2.3 kbar), high-temperature (575-degrees-C), oxygen-annealed ceramic La1.84Sr0.16CuO4 + delta by high-resolution neutron powder diffraction to determine its low-temperature structural properties in comparison to similarly oxygenated La2CuO4 + delta. Unlike La2CuO4 + delta, the Sr-containing superconductor shows no low-temperature phase separation. Further, the interstitial oxygen appears to be located at (1/4,1/4,z) with z = 0.163(5) and to have a value of delta-consistent with La1.84Sr0.16CuO4.019. Such a site is significantly displaced away from the interstitial location, (1/4,1/4,z), with z = 0.25, observed in La2CuO4 + delta and La2NiO4 + delta. The environment of such an interstitial site is suggestive of a smaller, neutral oxygen rather than a charged species. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP MOROSIN, B (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 21 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 OCT 1 PY 1991 VL 44 IS 14 BP 7673 EP 7679 DI 10.1103/PhysRevB.44.7673 PG 7 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800057 ER PT J AU SINGH, D CLOUGHERTY, DP MACLAREN, JM ALBERS, RC WANG, CS AF SINGH, D CLOUGHERTY, DP MACLAREN, JM ALBERS, RC WANG, CS TI INFLUENCE OF THE LOCAL-SPIN-DENSITY CORRELATION FUNCTIONAL ON THE STABILITY OF BCC FERROMAGNETIC IRON SO PHYSICAL REVIEW B LA English DT Note ID GROUND-STATE PROPERTIES; BRILLOUIN-ZONE; SPECIAL POINTS; TOTAL-ENERGY AB The influence of local-spin-dependent correlation effects on the predicted stable ground-state phase of iron is reexamined with use of general-potential linearized augmented-plane-wave calculations. Differences in the form of the Vosko-Wilk-Nusair (VWN) local-spin-density functional used in previous studies are noted, since in previous studies significant additional approximations were made with respect to those of Vosko, Wilk, and Nusan [Can. J. Phys. 58, 1200 (1980)] and of MacLaren, Clougherty, and Albers [Phys. Rev. B 42, 3205 (1990)]. While the results of previous linear muffin-tin orbital calculations using the VWN functional predict a bcc ferromagnetic ground state, the present calculations show that the VWN spin-correlation effects fail to stabilize a bcc ground state. Considerable sensitivity to the form of the spin interpolation is found. C1 UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV MARYLAND,DEPT PHYS & ASTRON,COLLEGE PK,MD 20742. RP SINGH, D (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. RI Singh, David/I-2416-2012; Clougherty, Dennis/A-4519-2008 OI Clougherty, Dennis/0000-0002-7299-4898 NR 28 TC 23 Z9 23 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7701 EP 7703 DI 10.1103/PhysRevB.44.7701 PG 3 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800062 ER PT J AU CRAWFORD, MK HARLOW, RL MCCARRON, EM FARNETH, WE AXE, JD CHOU, H HUANG, Q AF CRAWFORD, MK HARLOW, RL MCCARRON, EM FARNETH, WE AXE, JD CHOU, H HUANG, Q TI LATTICE INSTABILITIES AND THE EFFECT OF COPPER-OXYGEN-SHEET DISTORTIONS ON SUPERCONDUCTIVITY IN DOPED LA2CUO4 SO PHYSICAL REVIEW B LA English DT Note ID STRUCTURAL PHASE-TRANSITIONS; LA2-XBAXCUO4; TEMPERATURE; TRANSPORT; MECHANISM; LA2NIO4; OXIDE AB Synchroton x-ray and neutron-diffraction measurements demonstrate that Nd3+ substitution at the La3+ site in both metallic and insulating La2-xSrxCuO4 induces low-temperature structural instabilities which reorient the tilting of the copper-oxygen octahedra. These structural transformations strongly affect superconductivity. In addition, there is a bicritical point involving phases of Bmab, Pccn, and P4(2)/ncm space-group symmetries in the structural phase diagram of La1.6-xNd0.4SrxCuO4 at x approximately 0.15. There are also anomalies in the structural transformation temperatures and the superconducting transition temperatures when x approximately 1/8, providing evidence for an electronic instability at this doping level. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. NATL INST STAND & TECHNOL,REACTOR E151,GAITHERSBURG,MD 20899. RP CRAWFORD, MK (reprint author), DUPONT CO,EXPTL STN,CENT RES & DEV,POB 80356,WILMINGTON,DE 19880, USA. NR 35 TC 249 Z9 250 U1 3 U2 15 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1991 VL 44 IS 14 BP 7749 EP 7752 DI 10.1103/PhysRevB.44.7749 PG 4 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800075 ER PT J AU TAKIGAWA, M SMITH, JL HULTS, WL AF TAKIGAWA, M SMITH, JL HULTS, WL TI TEMPERATURE-DEPENDENT ANISOTROPY OF CU(2) NUCLEAR-RELAXATION RATE IN YBA2CU3O7 BELOW TC SO PHYSICAL REVIEW B LA English DT Note ID SPIN-LATTICE RELAXATION; NORMAL STATE; DYNAMICS; EXCITATIONS; SITES; CU-63; NMR AB We have measured the anisotropy of the Cu(2) nuclear-spin-lattice relaxation rate in the superconducting state of YBa2Cu3O7 in a small magnetic field (0.44 T) and the temperature range 30-210 K. The anisotropy is almost temperature independent in the normal state but develops a nonmonotonic temperature dependence below T(c) with a minimum near 70-80 K. The isotopic ratio of the relaxation rates shows that the nuclear relaxation is due to magnetic processes in this temperature range, although an extrinsic quadrupolar relaxation process appears below 30 K. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP TAKIGAWA, M (reprint author), IBM CORP,THOMAS J WATSON RES CTR,POB 218,YORKTOWN HTS,NY 10598, USA. NR 26 TC 84 Z9 84 U1 2 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 OCT 1 PY 1991 VL 44 IS 14 BP 7764 EP 7767 DI 10.1103/PhysRevB.44.7764 PG 4 WC Physics, Condensed Matter SC Physics GA GH808 UT WOS:A1991GH80800079 ER PT J AU DOVER, CB RICHARD, JM CARBONELL, J AF DOVER, CB RICHARD, JM CARBONELL, J TI ISOSPIN MIXING IN PROTONIUM AND ANNIHILATION DYNAMICS SO PHYSICAL REVIEW C LA English DT Article ID PBARP ANNIHILATION; NNBAR ANNIHILATION; ANTI-NUCLEONS; 2 MESONS; MODEL; LINEWIDTHS; SCATTERING; STATES; ETA AB We have explored the sensitivity of ppBAR-nnBAR isospin mixing in L = 0,1 atomic states of protonium to changes in the multipion-exchange contribution to the nucleon-antinucleon (NNBAR) potential. The resulting annihilation probabilities gamma-I-alpha for isospin I = 0,1 and state alpha = 2S + 1L(J) are combined with the spin-flavor weights for transitions NNBAR --> M1M2 in the 3P0 model, and confronted with selected measured branching ratios. Some problems with the phenomenology of the 3P0 model are identified. We compare the 3P0 model with a phenomenological ansatz suggested by Klempt, in which branching ratios are written as a product of spin, isospin, and orbital factors, multiplified by gamma-I-alpha. C1 CERN,DIV THEORY,CH-1211 GENEVA 23,SWITZERLAND. UNIV JOSEPH FOURIER,INST NATL PHYS NUCL & PHYS PARTICULES,INST SCI NUCL,CNRS,F-38026 GRENOBLE,FRANCE. RP DOVER, CB (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 26 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1281 EP 1288 DI 10.1103/PhysRevC.44.1281 PG 8 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700013 ER PT J AU BOGDANOVA, LN HALE, GM MARKUSHIN, VE AF BOGDANOVA, LN HALE, GM MARKUSHIN, VE TI ANALYTICAL STRUCTURE OF THE S-MATRIX FOR THE COUPLED CHANNEL PROBLEM D+T REVERSIBLE N+A AND THE INTERPRETATION OF THE J(PI) = 3/2(+) RESONANCE IN HE-5 SO PHYSICAL REVIEW C LA English DT Article ID NUCLEAR AB Using a resonance coupled channel model that provides a good description of the experimental data on the reaction d + t <--> n + alpha and d-t elastic scattering in the region of the resonance He-5(3+/2), we find the disposition of the S-matrix poles on the different Riemann sheets. An investigation of the motion of the poles with variation of the coupling strengths reveals the structure of the resonant state. The role of scattering and confined channels in the formation of the physical resonance is considered with the use of the probability sum rule for the confined channel. We demonstrate that the resonance He-5(3+/2) proves to be a coupled channel pole associated predominantly with the d-t system. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. IV KURCHATOV ATOM ENERGY INST,MOSCOW 123182,RUSSIA. RP BOGDANOVA, LN (reprint author), MOSCOW THEORET & EXPTL PHYS INST,MOSCOW 117259,RUSSIA. NR 20 TC 23 Z9 23 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1289 EP 1295 DI 10.1103/PhysRevC.44.1289 PG 7 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700014 ER PT J AU BROWN, VR ANTHONY, PL FRANKLIN, J AF BROWN, VR ANTHONY, PL FRANKLIN, J TI PROTON-PROTON BREMSSTRAHLUNG CALCULATIONS AT 280 MEV SO PHYSICAL REVIEW C LA English DT Article ID MODEL AB Proton-proton bremsstrahlung calculations are compared to the 280-MeV experimental results from TRIUMF, which use a polarized proton beam. Calculations are included for all experimental results. The Bonn radial potential is compared to a modified Hamada-Johnston and the Bryan-Gersten potentials. Potentials with different short-range radial behavior are compared in order to examine the penetration of the photon radiation. Rather good agreement with experiment for the Bonn potential is achieved without the arbitrary normalization of 2/3 applied to the TRIUMF cross-section data. The rescattering included in our work accounts for an increase of up to approximately 20% in the cross section, which is not large enough to explain the differences with other calculations, and it contributes up to a factor of 2.5 in the analyzing power. Our present results include partial waves up to J(max) = 6. C1 TEMPLE UNIV,DEPT PHYS,PHILADELPHIA,PA 19122. RP BROWN, VR (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. OI Franklin, Jerrold/0000-0003-4665-3026 NR 19 TC 36 Z9 36 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1296 EP 1310 DI 10.1103/PhysRevC.44.1296 PG 15 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700015 ER PT J AU PICKLESIMER, A RICE, RA BRANDENBURG, R AF PICKLESIMER, A RICE, RA BRANDENBURG, R TI DELTA-DEGREES OF FREEDOM IN TRINUCLEI .1. THE HANNOVER ONE-DELTA MODEL SO PHYSICAL REVIEW C LA English DT Article ID TRITON BINDING-ENERGY; NUCLEON-NUCLEON POTENTIALS; 3-NUCLEON FORCE; GROUND-STATE; MATTER; 2-NUCLEON; RESONANCE; HE-3 AB The shift in binding energy that results from allowing one explicit DELTA in the triton is studied using the Hannover one-DELTA force model. The one-DELTA analysis extends through J less-than-or-equal-to 4, subject only to L (N-DELTA) less-than-or-equal-to 4. Our main result is a 103-channel triton binding energy of 7.83 MeV, which corresponds to a net attractive one-DELTA effect of 370 keV. The corresponding (repulsive) dispersive effect is found to be 600 keV, so that the full one-DELTA three-body-force effect is 970 keV. Appropriately restricted J less-than-or-equal-to 2 calculations substantiate the basic results of the original Hannover triton calculations, although differences are found. The original J less-than-or-equal-to 2 figures are in good agreement with our full results and dissecting our results shows this to be largely due to cancellations among the various truncations employed in the original calculations. A numerical correction is obtained for each truncation and these are found to be relatively independent of each other. This forms a reliable basis for subsequent DELTA-DELTA studies. The Hannover one-DELTA model is also critically examined for physical consistency and the 1S0 effective range is found to be about 0.1 fm too low, a defect which could be responsible for about half of the net 370-keV increase in triton binding. The approach, methods, and numerical checks that underlie our investigations are also detailed. C1 PURDUE UNIV, DEPT PHYS, W LAFAYETTE, IN 47907 USA. UNIV BASEL, INST PHYS, CH-3056 BASEL, SWITZERLAND. RP LOS ALAMOS NATL LAB, DIV PHYS, LOS ALAMOS, NM 87545 USA. NR 38 TC 35 Z9 35 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1359 EP 1379 DI 10.1103/PhysRevC.44.1359 PG 21 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700020 ER PT J AU GAO, WB LEE, IY BAKTASH, C WYSS, R HAMILTON, JH STEELE, CM YU, CH JOHNSON, NR MCGOWAN, FK AF GAO, WB LEE, IY BAKTASH, C WYSS, R HAMILTON, JH STEELE, CM YU, CH JOHNSON, NR MCGOWAN, FK TI HIGH-SPIN SPECTROSCOPY AND LIFETIME MEASUREMENTS IN HF-169 SO PHYSICAL REVIEW C LA English DT Article ID ROTATIONAL BANDS; PAIRING REDUCTION; STATES; HF-163-166; ALIGNMENT; NUCLEI; REGION AB Two experiments were carried out to study the gamma-ray spectroscopy and lifetimes of the high-spin states of 169Hf, using the reaction Te-130(Ca-44,5n). The yrast band has been extended to I-pi = 81+/2 from the previously known I-pi = 45+/2. Three other bands were also extended to higher spin. The experimental Routhians, alignments, and signature splittings were interpreted within the framework of the cranked shell model (CSM). Good agreement is obtained between experimental results and the CSM calculations for the first band crossings due to i13/2 neutron alignments. The nature of the second upbends observed in (+, +1/2), (-, +1/2), and (-, -1/2) bands is discussed. Lifetimes of 17 high-spin levels within range 39/2 < I < 61/2 in four different bands were measured by using the Doppler shift attenuation method. The values of transition quadrupole moments derived from the measured lifetimes are compared with the results of total Routhian surface calculations, and a general agreement is obtained. C1 OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. MIT,DEPT NUCL ENGN,CAMBRIDGE,MA 02139. RP GAO, WB (reprint author), VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235, USA. NR 34 TC 19 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1380 EP 1396 DI 10.1103/PhysRevC.44.1380 PG 17 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700021 ER PT J AU HASS, M BENCZERKOLLER, N KUMBARTZKI, G LAURITSEN, T KHOO, TL AHMAD, I CARPENTER, MP JANSSENS, RVF MOORE, EF WOLFS, FLH BENET, P BEARD, K AF HASS, M BENCZERKOLLER, N KUMBARTZKI, G LAURITSEN, T KHOO, TL AHMAD, I CARPENTER, MP JANSSENS, RVF MOORE, EF WOLFS, FLH BENET, P BEARD, K TI DECAY HISTORY AND MAGNETIC-MOMENTS AT HIGH-SPIN IN DY-152 SO PHYSICAL REVIEW C LA English DT Article ID STATES; FIELDS AB Average magnetic moments as well as information on the time evolution of the continuum structure of 152Dy at high spin have been obtained using the transient hyperfine magnetic field acting on fast ions traversing a thin, magnetized gadolinium foil. 152Dy nuclei were populated by the Ge-76(Se-80,4n)152Dy fusion-evaporation reaction at E(Se-80) = 326.5 MeV. The target-ferromagnet arrangement corresponds to a time window of about 70 < t < 1100 fs, during which the excited nuclei experience the transient field interaction. The statistical gamma-rays, as well as the high-energy, E-gamma > 1200 keV, gamma-rays contributing to the collective E2 ''bump,'' exhibit a negligible precession, in accordance with the very short lifetimes of these states. The precession of the angular distribution of discrete yrast gamma-rays deexciting the nucleus from spin I approximately 35HBAR down yields an average magnetic moment for states with 43HBAR greater-than-or-equal-to I greater-than-or-equal-to 31HBAR. The resulting = 0.21(2) is considerably lower than the collective value Z/A approximately 0.43 and indicates an appreciable contribution from aligned neutrons to the lower-spin region populated within the above time frame. The results are discussed in the framework of model calculations of the gamma-ray cascade. C1 RUTGERS STATE UNIV,NEW BRUNSWICK,NJ 08903. ARGONNE NATL LAB,ARGONNE,IL 60439. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV NOTRE DAME,NOTRE DAME,IN 47907. RP HASS, M (reprint author), UNIV ROCHESTER,NUCL STRUCT RES LAB,ROCHESTER,NY 14627, USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 21 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1397 EP 1404 DI 10.1103/PhysRevC.44.1397 PG 8 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700022 ER PT J AU REEDER, PL WARNER, RA HENSLEY, WK VIEIRA, DJ WOUTERS, JM AF REEDER, PL WARNER, RA HENSLEY, WK VIEIRA, DJ WOUTERS, JM TI HALF-LIVES AND DELAYED NEUTRON EMISSION PROBABILITIES OF NEUTRON-RICH LI-AL NUCLIDES SO PHYSICAL REVIEW C LA English DT Article ID DIRECT MASS MEASUREMENTS; SHELL-MODEL PREDICTIONS; BETA-DECAY; LIFETIME MEASUREMENTS; MAGNESIUM ISOTOPES; TOFI SPECTROMETER; LIGHT ISOTOPES; NUCLEI; RADIOACTIVITY; LI-11 AB Beta-decay half-lives and delayed neutron emission probabilities of very neutron-rich nuclides from Li to Al have been measured by a delayed coincidence technique. Neutron-rich nuclides were produced by reaction of 800-MeV protons on a Th-232 target and were individually identified by use of the time-of-flight isochronous spectrometer. For 16 previously measured nucides, the half-lives determined here agree with literature values within the uncertainties. The previously unmeasured half-lives for 25F (59 +/- 40 ms) and 28Ne (14 +/- 10 ms) have been determined. Delayed neutron emission has been measured for Be-12, B-14, C-17, N-18, 25F, and 28Ne. Emission probabilities are reported for 19 precursors and upper limits are reported for 12 other nuclides. These data are compared with predictions of several beta-decay models. C1 LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RP REEDER, PL (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 66 TC 45 Z9 45 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1435 EP 1453 DI 10.1103/PhysRevC.44.1435 PG 19 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700025 ER PT J AU WARBURTON, EK AF WARBURTON, EK TI SHELL-MODEL DESCRIPTION OF BI-211 (BETA-)PO-211 AND AT-211(EC) PO-211 AND THE SPECTROSCOPY OF PO-211 SO PHYSICAL REVIEW C LA English DT Article AB A recent treatment of first-forbidden beta- decay in the lead region is extended to beta+ decay and electron capture. The modified Kuo-Herling shell-model interaction recently described by Warburton and Brown is used to calculate wave functions and observables for Po-211. The logf0t values for the Bi-211(9-/2) --> Po-211(9+/2) beta- transition and the electron capture of At-211(9-/2) into the 9+/2(1) and 11+/2(1) states of Po-211 are predicted to be 6.008, 5.891, and 5.850 as compared to the experimental values of 6.026 +/- 0.017, 5.960 +/- 0.008, and 5.831 +/- 0.090, respectively. The wave functions and spectrum of Po-211 are calculated in the Kuo-Herling model space. The yrast spectrum is presented for comparison to anticipated results from fusion-evaporation reaction studies. The experimental Po-210(d, p)Po-211 spectroscopic factors are quite accurately reproduced. RP WARBURTON, EK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 21 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1500 EP 1507 DI 10.1103/PhysRevC.44.1500 PG 8 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700033 ER PT J AU BUTSCH, R HOFMAN, DJ MONTOYA, CP PAUL, P THOENNESSEN, M AF BUTSCH, R HOFMAN, DJ MONTOYA, CP PAUL, P THOENNESSEN, M TI TIME SCALES FOR FUSION-FISSION AND QUASI-FISSION FROM GIANT-DIPOLE RESONANCE DECAY SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION REACTIONS; NEUTRON EMISSION; NUCLEAR DISSIPATION; PRE-SCISSION; ANGULAR-DISTRIBUTIONS; PARTICLE-EMISSION; DIFFUSION PROCESS; QUASI-FISSION; MODEL; MULTIPLICITIES AB Giant dipole resonance (GDR) gamma-rays in coincidence with fission fragments were measured in the reactions O-16 + Pb-208 at 120 and 140 MeV, Mg-24 + Pt-196 at 150 MeV, and S-32 + (nat)W at 185 MeV. gamma-ray-fission angular correlation measurements for O-16 + Pb-208 (120 and 140 MeV) and S-32 + (nat)W confirm the strong contribution of prescission gamma-rays to the total gamma-ray spectrum. The data were analyzed with a modified statistical model code which includes the effects of nuclear dissipation in the fission process, gamma decay at equilibrium and between saddle and scission, and the decay of the mononucleus formed in quasifission reactions. The extracted value for the nuclear friction coefficient of gamma = 10 +/- 3 at temperatures between 1 and 2 MeV is much larger than the upper limit for the ground state and indicates strongly overdamped large-scale mass motion. The extracted total fission time scale tau-fiss(gamma = 10) congruent-to 2.9 x 10(-19) s at 64 MeV excitation energy agrees with that extracted from recent neutron multiplicity experiments. A strong dependence of the GDR gamma-ray yield on the target-projectile mass asymmetry is interpreted in terms of the quasifission process. gamma-ray spectra and correlations could be fitted with the assumption of a GDR contribution from the mononucleus but required an arbitrary reduction of the total fission fragment excitation energy by 30 MeV. The quasifission lifetime was estimated to tau-qf = (2-9) x 10(-20) s. C1 SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 62 TC 85 Z9 85 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1515 EP 1527 DI 10.1103/PhysRevC.44.1515 PG 13 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700035 ER PT J AU CHINN, CR ELSTER, C THALER, RM AF CHINN, CR ELSTER, C THALER, RM TI MOMENTUM-SPACE TREATMENT OF COULOMB DISTORTIONS IN A MULTIPLE-SCATTERING EXPANSION SO PHYSICAL REVIEW C LA English DT Article ID FULL-FOLDING-MODEL; ELASTIC-SCATTERING; INTERMEDIATE ENERGIES; MESON-EXCHANGE; POTENTIALS; NUCLEAR; PROTONS AB The momentum-space treatment of the Coulomb interaction within the framework of the Watson multiple-scattering expansion is derived and tested numerically. By neglecting virtual Coulomb excitations and higher-order terms, the lowest-order optical potential for proton-nucleus scattering is shown to be the sum of the convolutions of a two-body nucleon-nucleon t matrix with the nuclear density and the point Coulomb interaction with the nuclear charge density. The calculation of the optical potential, as well as the treatment of the Coulomb interaction, is performed entirely in momentum space in an exact and numerically stable procedure. Elastic-scattering observables are presented for O-16, Ca-40, and Pb-208 at energies up to 500 MeV. Comparisons are made with approximate treatments of the Coulomb interaction. The interference of nonlocality effects in the nuclear optical potential with different treatments of the Coulomb interaction is investigated. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP CHINN, CR (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. RI Elster, Charlotte/N-9845-2015 NR 27 TC 27 Z9 27 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1569 EP 1580 DI 10.1103/PhysRevC.44.1569 PG 12 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700041 ER PT J AU DOVER, CB HEINZ, U SCHNEDERMANN, E ZIMANYI, J AF DOVER, CB HEINZ, U SCHNEDERMANN, E ZIMANYI, J TI COVARIANT COALESCENCE MODEL FOR RELATIVISTICALLY EXPANDING SYSTEMS SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; QUARK-GLUON PLASMA; LAMBDA-BAR-PRODUCTION; NUCLEAR COLLISIONS; 200 GEV/NUCLEON; H-DIBARYON; GEV/C; PARTICLE; BARYONS; SULFUR AB We develop a covariant coalescence model for relativistically expanding fireballs formed in high-energy nuclear collisions and apply it to predict the formation rate of light nuclei and antinuclei (d,dBAR) as well as of the H dibaryon and the pentaquark P0 in relativistic heavy-ion collisions at the CERN Super Proton Synchotron and the Brookhaven Alternating Gradient Synchrotron Accelerators. For the dBAR and H, our predictions differ significantly from previous results based on a nonrelativistic analysis. C1 UNIV REGENSBURG, DEPT THEORET PHYS, W-8400 REGENSBURG, GERMANY. CENT RES INST PHYS, H-1525 BUDAPEST 114, HUNGARY. RP BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. NR 60 TC 61 Z9 61 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1636 EP 1654 DI 10.1103/PhysRevC.44.1636 PG 19 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700049 ER PT J AU HE, YD PRICE, PB AF HE, YD PRICE, PB TI SEARCH FOR FRACTIONAL CHARGE STATES IN HIGH-ENERGY HEAVY FRAGMENTS PRODUCED IN COLLISIONS OF 14.5A GEV SI-28 WITH PB AND CU TARGET SO PHYSICAL REVIEW C LA English DT Note ID PROJECTILE FRAGMENTS; ION COLLISIONS; NUCLEI AB We used nuclear track detectors to construct the trajectories of interactions and to measure with high resolution the charge of the beam and of heavy nuclear fragments produced in interactions. A null result of our search for fractional charge states in high-energy fragments with charges 8 less-than-or-equal-to Z less-than-or-equal-to 13 produced in collisions of 14.5 A GeV Si-28 nuclei with Pb and Cu targets leads us to conclude that the upper limits for the probability of production of a fragment with charge 23/3, 25/3, 26/3 28/3 29/3, 31/3 32/3, 34/3, 35/3, 37/3, or 38/3 charge unit in Pb and Cu at 90% confidence level are 1.9 X 10(-4) and 3.9 X 10(-4), respectively. We set a similar limit on the relative number of particle-stable fragments with 8 less-than-or-equal-to Z less-than-or-equal-to 14 created in the central rapidity region. C1 UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. RP HE, YD (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 13 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1672 EP 1674 DI 10.1103/PhysRevC.44.1672 PG 3 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700054 ER PT J AU KOEHLER, PE AF KOEHLER, PE TI CL-35 (N,P)S-35 CROSS-SECTION FROM 25 MEV TO 100 KEV SO PHYSICAL REVIEW C LA English DT Note ID NEUTRON AB We have measured the Cl-35(n,p)S-35 cross section from 25 meV to 100 keV. Strengths were determined for the resonances at E(n) = 398, 4249, 16 340, 27 316, and 57 700 eV. The proton width for the J-pi = 2+ state just below threshold was calculated using previously known resonance parameters and the thermal cross section. The cross section calculated from the parameters for this state was found to be in good agreement with our data to approximately 100 eV. The astrophysical reaction rate, N(A) , was calculated from the resonance strengths determined in our measurements, plus the thermal cross section. The role of this reaction in the nucleosynthesis of light elements in the s process as well as in explosive nucleosynthesis is discussed. RP KOEHLER, PE (reprint author), LOS ALAMOS NATL LAB,DIV PHYS,GRP P-17,LOS ALAMOS,NM 87545, USA. OI Koehler, Paul/0000-0002-6717-0771 NR 19 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 OCT PY 1991 VL 44 IS 4 BP 1675 EP 1678 DI 10.1103/PhysRevC.44.1675 PG 4 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700055 ER PT J AU WESTPHAL, AJ JING, GR PRICE, PB AF WESTPHAL, AJ JING, GR PRICE, PB TI MEASUREMENT OF CROSS-SECTIONS FOR CHARGE PICKUP BY RELATIVISTIC HOLMIUM IONS ON HEAVY TARGETS SO PHYSICAL REVIEW C LA English DT Note ID ATOMIC-COLLISIONS AB We have measured the cross section for nuclear charge pickup by relativistic holmium on several targets of larger atomic number than have been studied previously. We find that although measurements made with most of the targets are consistent with a peripheral geometric scaling, one target, silver, shows an anomalously high cross section. C1 LAWRENCE BERKELEY LAB, DIV NUCL SCI, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. NR 8 TC 18 Z9 18 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP 1687 EP 1690 DI 10.1103/PhysRevC.44.1687 PG 4 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700058 ER PT J AU DRACOULIS, GD FABRICIUS, B STUCHBERY, AE MACCHIAVELLI, AO KORTEN, W AZAIEZ, F RUBEL, E DELEPLANQUE, MA DIAMOND, RM STEPHENS, FS AF DRACOULIS, GD FABRICIUS, B STUCHBERY, AE MACCHIAVELLI, AO KORTEN, W AZAIEZ, F RUBEL, E DELEPLANQUE, MA DIAMOND, RM STEPHENS, FS TI SHAPE COEXISTENCE FROM THE STRUCTURE OF THE YRAST BAND IN PT-174 SO PHYSICAL REVIEW C LA English DT Note ID NEUTRON-DEFICIENT; ISOTOPES AB Excited states in the very neutron-deficient nucleus Pt-174 have been identified up to spin 14. An irregular yrast sequence was observed beginning with a high 2+ --> 0+ energy. It can be interpreted as the result of a change from a weakly deformed ground-state band, to a well-deformed rotor, near spin 6. C1 LAWRENCE BERKELEY LAB, DIV NUTR SCI, BERKELEY, CA 94720 USA. UNIV CALIF DAVIS, DAVIS, CA 95616 USA. INST NATL PHYS NUCL & PHYS PARTICULES, CTR ETUDES NUCL BORDEAUX GRADIGNAN, F-33170 GRADIGNAN, FRANCE. RP AUSTRALIAN NATL UNIV, RES SCH PHYS SCI & ENGN, DEPT NUCL PHYS, POB 4, CANBERRA, ACT 2601, AUSTRALIA. RI Dracoulis, George/A-8123-2008; KORTEN, Wolfram/H-3043-2013 NR 10 TC 45 Z9 45 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 1991 VL 44 IS 4 BP R1246 EP R1249 PG 4 WC Physics, Nuclear SC Physics GA GK737 UT WOS:A1991GK73700004 ER PT J AU HEINRICH, JG BIINO, C GREENHALGH, JF LOUIS, WC MCDONALD, KT PALESTINI, S RUSSELL, DP SHOEMAKER, FC SMITH, AJS ADOLPHSEN, CE ALEXANDER, JP ANDERSON, KJ CONWAY, JS PILCHER, JE POSSOZ, A ROSENBERG, EI AF HEINRICH, JG BIINO, C GREENHALGH, JF LOUIS, WC MCDONALD, KT PALESTINI, S RUSSELL, DP SHOEMAKER, FC SMITH, AJS ADOLPHSEN, CE ALEXANDER, JP ANDERSON, KJ CONWAY, JS PILCHER, JE POSSOZ, A ROSENBERG, EI TI HIGHER-TWIST EFFECTS IN THE REACTION PI-N-]MU+MU-X AT 253GEV/C SO PHYSICAL REVIEW D LA English DT Article ID DRELL-YAN PROCESS; PION STRUCTURE-FUNCTION; HADRON COLLISIONS; PAIR PRODUCTION; MUON PAIRS; QCD; MECHANISM; GEV/C AB The distributions of quarks in the pion and nucleon are extracted from measurements of the reaction pi- N --> mu+mu- X at 253 GeV/c in a naive Drell-Yan analysis, as well as QCD-corrected analyses at leading-log and next-to-leading-log order. As x-pi --> 1 the pion structure function shows a term that varies as 1/m-mu-mu-4, which we interpret as a higher-twist effect. Additionally, the angular distribution of the mu+ in the muon-pair rest frame tends towards sin2-theta as x-pi --> 1 and as m-mu-mu --> 0 in a manner consistent with higher-twist effects. When the strongly mass-dependent higher-twist effects are included as part of the pion structure function, the nucleon structure function agrees well with leading-twist results from deeply inelastic lepton-hadron scattering. A significant advance of the present work is the extension of the analysis to low masses by the subtraction of the J/psi and psi' resonances from the continuum. Our analysis covers the kinematic range 0.4 < x-pi < 1.0 and 0.02 < x(N) < 0.33 with 3.0 < m-mu-mu < 8.55 GeV/c2. Cross sections for psi' production are presented in an appendix. C1 UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP HEINRICH, JG (reprint author), PRINCETON UNIV,JOSEPH HENRY LABS,PRINCETON,NJ 08544, USA. NR 31 TC 50 Z9 50 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 1909 EP 1932 DI 10.1103/PhysRevD.44.1909 PG 24 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000003 ER PT J AU BOSSHARD, A AMSLER, C DOBELI, M DOSER, M SCHAAD, M RIEDLBERGER, J TRUOL, P BISTIRLICH, JA CROWE, KM LJUNGFELT, S MEYER, CA VANDENBRANDT, B KONTER, JA MANGO, S RENKER, D LOUDE, JF PERROUD, JP HADDOCK, RP SOBER, DI AF BOSSHARD, A AMSLER, C DOBELI, M DOSER, M SCHAAD, M RIEDLBERGER, J TRUOL, P BISTIRLICH, JA CROWE, KM LJUNGFELT, S MEYER, CA VANDENBRANDT, B KONTER, JA MANGO, S RENKER, D LOUDE, JF PERROUD, JP HADDOCK, RP SOBER, DI TI ANALYZING POWER IN PION-PROTON BREMSSTRAHLUNG, AND THE DELTA++(1232) MAGNETIC-MOMENT SO PHYSICAL REVIEW D LA English DT Article ID DELTA(1236) RESONANCE; ENERGY PHOTONS; SCATTERING AB We report on a first measurement of the polarized-target asymmetry of the pion-proton bremsstrahlung cross section (pi + p --> pi + p-gamma). As in previous cross section measurements the pion energy (298 MeV) and the detector geometry for this experiment was chosen to optimize the sensitivity to the radiation from the magnetic dipole moment of the DELTA++(1232) resonance-mu-DELTA. Comparison to a recent isobar model for pion-nucleon bremsstrahlung yields-mu-DELTA = (1.62 +/- 0.18) mu-p, where mu-p is the proton magnetic moment. Since the asymmetry depends less than the cross section on the choice of the other input parameters for the model, their uncertainties affect this analysis by less than the experimental error. However the theory fails to represent both the cross section and the asymmetry data at the highest photon energies. Hence further improvements in the calculations are needed before the model dependence of the magnetic moment analysis can be fully assessed. The present result agrees with bag-model corrections to the SU(6) prediction mu-DELTA = 2-mu-p. As a by-product, the analyzing power for elastic-pi + p scattering at 415 MeV/c was also measured. This second result is in good agreement with phase shift calculations. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. PAUL SCHERRER INST,CH-5232 VILLIGEN,SWITZERLAND. UNIV LAUSANNE,INST PHYS NUCL,CH-1015 LAUSANNE,SWITZERLAND. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. CATHOLIC UNIV AMER,DEPT PHYS,WASHINGTON,DC 20064. RP BOSSHARD, A (reprint author), UNIV ZURICH,INST PHYS,CH-8001 ZURICH,SWITZERLAND. RI Meyer, Curtis/L-3488-2014 OI Meyer, Curtis/0000-0001-7599-3973 NR 40 TC 83 Z9 84 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 1962 EP 1974 DI 10.1103/PhysRevD.44.1962 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000006 ER PT J AU BERGER, EL QIU, JW AF BERGER, EL QIU, JW TI CALCULATIONS OF PROMPT-PHOTON PRODUCTION IN QCD SO PHYSICAL REVIEW D LA English DT Article ID OPTIMIZED PERTURBATION-THEORY; DEEP INELASTIC-SCATTERING; SCHEME-INVARIANT QCD; DRELL-YAN PROCESS; PARTON DISTRIBUTIONS; CROSS-SECTIONS; COLLISIONS; FACTORIZATION; DEPENDENCE; MOMENTUM AB Cross sections for prompt-photon production at collider energies are not strictly inclusive because an isolation requirement is imposed whereby the photon is detected only if accompanied by a restricted amount of hadronic energy. In this paper we provide a consistent treatment of the isolated prompt-photon cross section in QCD pertubation theory. The isolation requirement reduces sensitivity of the cross section to poorly known long-distance fragmentation contributions. However, the normal cancellation of infrared singularities is upset by the isolation cutoffs, rendering the short-distance perturbative calculation highly nontrivial. In our solution we address both the short- and the long-distance issues in detail, showing that well-behaved predictions can be derived for a wide range of isolation parameters. Calculated cross sections are presented at several energies and scale dependence of the cross section is examined. C1 SUNY STONY BROOK,INST THEORET PHYS,STONY BROOK,NY 11794. RP BERGER, EL (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439, USA. NR 41 TC 77 Z9 77 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 2002 EP 2024 DI 10.1103/PhysRevD.44.2002 PG 23 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000010 ER PT J AU WARD, BFL AF WARD, BFL TI NUMBER OF B-MESONS NEEDED TO OBSERVE CP VIOLATION SO PHYSICAL REVIEW D LA English DT Article AB We analyze three relativistically invariant models of the decay B0 --> psi/J K+* from the standpoint of the CP parity of the final state. In all three models, we find that CP = even final states are dominant in agreement with recent observations by ARGUS. This reduces significantly the required luminosity to observe CP violation in B-factory-type devices. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP WARD, BFL (reprint author), STANFORD LINEAR ACCELERATOR CTR,POB 4349,STANFORD,CA 94309, USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 2050 EP 2053 DI 10.1103/PhysRevD.44.2050 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000014 ER PT J AU BOULWARE, M FINNELL, D AF BOULWARE, M FINNELL, D TI RADIATIVE-CORRECTIONS TO B(Z-]BBBAR) IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL SO PHYSICAL REVIEW D LA English DT Article ID ONE-LOOP CORRECTIONS; HIGGS BOSONS; TOP; PHYSICS; MASS AB We examine one-loop vertex corrections to the process Z --> bbBAR in the minimal supersymmetric standard model. The amplitude for this process may be enhanced by large Yukawa couplings which arise in the case of a heavy top or a very large value of tan-beta. This leads to the possibility that supersymmetry might be observed indirectly by precision measurements of B(Z --> bbBAR). RP BOULWARE, M (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 13 TC 152 Z9 152 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 2054 EP 2063 DI 10.1103/PhysRevD.44.2054 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000015 ER PT J AU BERNSTEIN, RH PARKE, SJ AF BERNSTEIN, RH PARKE, SJ TI TERRESTRIAL LONG-BASE-LINE NEUTRINO-OSCILLATION EXPERIMENTS SO PHYSICAL REVIEW D LA English DT Article ID MATTER AB We present a systematic study of potential long-baseline (distances > 300 km) neutrino-oscillation experiments performed with nu-mu and nu-muBAR beams from the Fermilab Main Injector (< E-nu > almost-equal-to 10-20 GeV). The effects of matter enhancement are included where appropriate. We find that there are three key variables for such an experiment: the length of the baseline, the muon energy threshold, and the minimum measurable oscillation probability. An advantage in one of these variables can easily be negated by a disadvantage in one of the others. Finally, for any long-baseline experiment at these energies to conclusively confirm or refute the interpretation of the atmospheric neutrino deficit as neutrino oscillations it must have a low energy threshold and a low minimum measurable oscillation probability. RP BERNSTEIN, RH (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. OI Bernstein, Robert/0000-0002-7610-950X NR 30 TC 27 Z9 27 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 2069 EP 2078 DI 10.1103/PhysRevD.44.2069 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000017 ER PT J AU BITAR, KM EDWARDS, R HELLER, UM KENNEDY, AD DEGRAND, TA GOTTLIEB, S KRASNITZ, A KOGUT, JB RENKEN, RL LIU, W ROSSI, P OGILVIE, MC SINCLAIR, DK WANG, KC SUGAR, RL TEPER, M TOUSSAINT, D AF BITAR, KM EDWARDS, R HELLER, UM KENNEDY, AD DEGRAND, TA GOTTLIEB, S KRASNITZ, A KOGUT, JB RENKEN, RL LIU, W ROSSI, P OGILVIE, MC SINCLAIR, DK WANG, KC SUGAR, RL TEPER, M TOUSSAINT, D TI GLUEBALLS AND TOPOLOGY IN LATTICE QCD WITH 2 LIGHT FLAVORS SO PHYSICAL REVIEW D LA English DT Article ID GAUGE-THEORY; MASSES; SU(3); SPECTRUM; SUSCEPTIBILITY; INSTANTONS; SCALAR; U(1) AB We obtain estimates of the lightest glueball masses, the string tension, and the topological susceptibility in an exploratory study of QCD with two light flavors of quarks. Our calculations are performed at beta = 5.6 with staggered quark masses m(q) = 0.010 and 0.025 and on lattices ranging from 12(4) to 16(4). Our estimates suggest that, just as in the pure gauge theory, the 0++ is the lightest glueball with the 2++ about 50% heavier. Our m(q) = 0.01 results predict a 0++ glueball mass of about 1.6 times the rho mass and the square root of the string tension of about 0.48 times the rho mass, which is surprisingly close to the usual phenomenologically motivated estimates of around 0.55. Our value of the topological susceptibility at m(q) = 0.01 is consistent with the prediction, to O(m(q)) of the standard anomalous Ward identity. However, the variation of this susceptibility between m(q) = 0.01 and m(q) = 0.025 is weaker than the linear dependence one expects at small m(q) in the broken-chiral-symmetry phase of QCD. C1 UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309. INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. THINKING MACHINES CORP,CAMBRIDGE,MA 02142. WASHINGTON UNIV,DEPT PHYS,ST LOUIS,MO 63130. ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. UNIV OXFORD,DEPT THEORET PHYS,OXFORD OX1 3NP,ENGLAND. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. UNIV OXFORD ALL SOULS COLL,OXFORD OX1 4AL,ENGLAND. RP BITAR, KM (reprint author), FLORIDA STATE UNIV,SUPERCOMP COMPUTAT RES INST,TALLAHASSEE,FL 32306, USA. OI Heller, Urs M./0000-0002-2780-5584 NR 26 TC 34 Z9 34 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 1991 VL 44 IS 7 BP 2090 EP 2109 DI 10.1103/PhysRevD.44.2090 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA GH860 UT WOS:A1991GH86000020 ER PT J AU BROW, RK TALLANT, DR OSBORNE, ZA YANG, Y DAY, DE AF BROW, RK TALLANT, DR OSBORNE, ZA YANG, Y DAY, DE TI THE EFFECT OF FLUORINE ON THE STRUCTURE OF PHOSPHATE-GLASS SO PHYSICS AND CHEMISTRY OF GLASSES LA English DT Article ID PHOSPHORUS OXYNITRIDE GLASSES; FLUOROPHOSPHATE GLASSES; RAMAN-SPECTRA; ALUMINUM FLUORIDE; MOLTEN CRYOLITE; SPECTROSCOPY; MELTS; XPS AB We have used x-ray photoelectron and Raman spectroscopies to characterise the effect of the incorporation of F on the short range structure of Na-P-O and Na-Al-P-O glasses. The incorporation of F into NaPO3 depolymerises the glass structure by preferentially replacing bridging oxygen with chain terminating P-F bonds. The addition of AlF3 to NaPO3 modifies the phosphate network primarily by linking Al(O,F) polyhedra with P(O,F)4 tetrahedra. Remelting these latter glasses with NH4HF2 increases their F contents and depolymerises the structure through the formation of additional P-F and Al-F bonds at the expense of the bridging POAl bonds. Changes in glass properties are sensitive to these structural modifications. C1 UNIV MISSOURI,ROLLA,MO 65401. RP BROW, RK (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 25 TC 45 Z9 46 U1 3 U2 17 PU SOC GLASS TECHNOLOGY PI SHEFFIELD PA THORNTON 20 HALLAM GATE ROAD, SHEFFIELD, S YORKSHIRE, ENGLAND S10 5BT SN 0031-9090 J9 PHYS CHEM GLASSES JI Phys. Chem. Glasses PD OCT PY 1991 VL 32 IS 5 BP 188 EP 195 PG 8 WC Chemistry, Physical; Materials Science, Ceramics SC Chemistry; Materials Science GA GK231 UT WOS:A1991GK23100002 ER PT J AU DURKEE, JW ANTICH, PP AF DURKEE, JW ANTICH, PP TI CHARACTERIZATION OF BIOHEAT TRANSPORT USING AN EXACT SOLUTION TO THE CYLINDRICAL GEOMETRY, MULTIREGION, TIME-DEPENDENT BIOHEAT EQUATION SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID SKIN AB An exact solution is obtained to the classical time-dependent linear bioheat equation in one-dimensional multi-region cylindrical geometry with temperature-invariant physiological parameters. This solution complements the previously reported solutions for Cartesian and spherical geometries, enabling the study of transient temperature behaviour in an arbitrary number of coupled physiologically distinct regions for the three basic one-dimensional geometries. 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 12 TC 12 Z9 12 U1 0 U2 1 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 OCT PY 1991 VL 36 IS 10 BP 1377 EP 1406 DI 10.1088/0031-9155/36/10/006 PG 30 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA GK224 UT WOS:A1991GK22400006 ER PT J AU COWLEY, SC KULSRUD, RM SUDAN, R AF COWLEY, SC KULSRUD, RM SUDAN, R TI CONSIDERATIONS OF ION-TEMPERATURE-GRADIENT-DRIVEN TURBULENCE SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID DRIFT INSTABILITIES; MAGNETIC-FIELDS; TOROIDAL PLASMA; TRANSPORT; TOKAMAKS; MODES; FLUCTUATIONS AB The ion-temperature-gradient-driven instability is considered in this paper. Physical pictures are presented to clarify the nature of the instability. The saturation of a single eddy is modeled by a simple nonlinear equation. It is shown that eddies that are elongated in the direction of the temperature gradient are the most unstable and have the highest saturation amplitudes. In a sheared magnetic field, such elongated eddies twist with the field lines. This structure is shown to be an alternative to the usual Fourier mode picture in which the mode is localized around the surface where k parallel-to = 0. These elongated twisting eddies, which are an integral part of the "ballooning mode" structure, could survive in a torus. The elongated eddies are shown to be unstable to secondary instabilities that are driven by the large gradients in the long eddy. It is argued that the "mixing length" is affected by this nonlinear process, and is unlikely to be a linear eigenmode width. C1 CORNELL UNIV,ITHACA,NY 14853. RP COWLEY, SC (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 27 TC 95 Z9 95 U1 2 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 OCT PY 1991 VL 3 IS 10 BP 2767 EP 2782 DI 10.1063/1.859913 PG 16 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500007 ER PT J AU FIGURA, ES MCCALL, GH DANGOR, AE AF FIGURA, ES MCCALL, GH DANGOR, AE TI CHARACTERISTICS OF A Z-PINCH PRODUCED FROM A GLASS OPTICAL FIBER SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID ELECTRON-BEAM; STABILITY; ABLATION AB A Z-pinch discharge in a quartz fiber (20-125-mu-m diameter) driven by a 150 kA current with a rise time of 50 nsec has been investigated. The pinch was found to develop an m = 0 instability during the time of current rise and before the whole fiber had been formed into a plasma. No anomalously stable behavior was seen. The bright spots associated with the instability expanded radially and moved in the axial direction with typical velocities of a few 10(6) cm sec-1. A coronal plasma was found to exist with density 10(16) cm-3 at a radius 500-mu-m. There was evidence of an energetic (20 keV) electron beam. The observed plasma expansion and ionization agreed well with a one-dimensional magnetohydrodynamic simulation. The simulation showed that the light which was observed to be generated in the core of the optical fiber was due to shock heating. The predicted temperature of the surface of the plasma was also in good agreement with an estimate of the temperature (25 +/- 8 eV) obtained by assuming that the light emission was blackbody. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. NR 24 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 OCT PY 1991 VL 3 IS 10 BP 2835 EP 2843 DI 10.1063/1.859917 PG 9 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500012 ER PT J AU TUSZEWSKI, M ARMSTRONG, WT CHRIEN, RE HUGRASS, WN MCKENNA, KF REJ, DJ SIEMON, RE TAGGART, DP WRIGHT, BL AF TUSZEWSKI, M ARMSTRONG, WT CHRIEN, RE HUGRASS, WN MCKENNA, KF REJ, DJ SIEMON, RE TAGGART, DP WRIGHT, BL TI AXIAL DYNAMICS IN FIELD-REVERSED THETA PINCHES .1. FORMATION SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PARTICLE LIFETIME MEASUREMENTS; CONFIGURATIONS; FLUX; PLASMA; CONFINEMENT; EQUILIBRIA; ENERGY; MODEL AB Bias field scans are performed at various fill pressures in the FRX-C [Fusion Technol. 9, 13 (1986)] and FRX-C/LSM [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. II, p. 517] field-reversed theta pinches. These data show a systematic degradation of the confinement properties of field-reversed configurations whenever strong axial implosions occur during plasma formation. This limitation prevents access to the desired regime of large-size and long-lived field-reversed configurations. The cause of the confinement degradation must be due to some formation or gross stability problem. Here many studies are reported that attempt to correlate confinement degradation with some formation characteristic. These investigations remain inconclusive and suggest further stability studies presented in a companion paper. RP TUSZEWSKI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 44 TC 17 Z9 17 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD OCT PY 1991 VL 3 IS 10 BP 2844 EP 2855 DI 10.1063/1.859918 PG 12 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500013 ER PT J AU TUSZEWSKI, M TAGGART, DP CHRIEN, RE REJ, DJ SIEMON, RE WRIGHT, BL AF TUSZEWSKI, M TAGGART, DP CHRIEN, RE REJ, DJ SIEMON, RE WRIGHT, BL TI AXIAL DYNAMICS IN FIELD-REVERSED THETA PINCHES .2. STABILITY SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PARTICLE LIFETIME MEASUREMENTS; INTERNAL TILT MODE; ROTATIONAL INSTABILITY; QUADRUPOLE STABILIZATION; CONFIGURATIONS; CONFINEMENT; PLASMA; FLUX; ENERGY AB Detailed stability studies are made with new diagnostics in the FRX-C/LSM field-reversed theta pinch [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. II, p. 517]. These studies seek the origin of a degradation of the confinement properties of field-reversed configurations (FRC's) that appears associated with strong axial dynamics during plasma formation. Several instabilities are observed, including rotational modes, interchanges, and tilt instabilities. Only the latter are strongly correlated with FRC confinement. Tilt instabilities are observed for FRC's with larger average number of ion gyroradii (s approximately 3-5) and smaller separatrix elongations (e approximately 3-4). Coincidently, strong axial dynamics occurs for cases with larger s and smaller e values, through increases in either reversed bias field or fill pressure. These data provide some understanding of FRC stability. In agreement with finite Larmor radius theory, there is a regime of gross stability for the very kinetic and elongated FRC's with s/e < 0.2-0.3. This is the regime that has been studied in most FRC experiments. However, tilt and other instabilities are observed for FRC's with s/e approximately 1. Additional stabilization techniques will be required for future large-size FRC's. RP TUSZEWSKI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 53 TC 45 Z9 45 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD OCT PY 1991 VL 3 IS 10 BP 2856 EP 2870 DI 10.1063/1.860000 PG 15 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500014 ER PT J AU WROBLEWSKI, D LAO, LL AF WROBLEWSKI, D LAO, LL TI DETERMINATION OF THE SAFETY FACTOR IN SAWTOOTHING DISCHARGES IN DIII-D SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID TOKAMAK; OSCILLATIONS; MECHANISM; POLARIZATION; POLARIMETRY; PROFILES; AXIS AB Local magnetic field pitch angle is determined in DIII-D tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (IAEA, Vienna, 1987), Vol. I, p. 159] by measuring the direction of polarization of Stark components of the D-alpha (deuterium Balmer-alpha) line emitted by the heating neutral beam. The measurement result is incorporated into the magnetic equilibrium code to provide a constraint on the calculated profiles of current density and safety factor (inverse rotational transform). The safety factor profiles obtained with the use of the polarimetry data indicate that the safety factor on axis q0 is close to 1.0 at the onset of the sawtooth instability but may be substantially smaller than 1.0 in later stages of a discharge. The magnetic field pitch angle variations associated with the sawtooth instability were observed in some discharges with a time resolution of about 10 msec. The increase of q0 during a sawtooth crash is found to be not larger than about 0.1 +/- 0.05. C1 GEN ATOM,SAN DIEGO,CA 92186. RP WROBLEWSKI, D (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 27 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 OCT PY 1991 VL 3 IS 10 BP 2877 EP 2881 PG 5 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500016 ER PT J AU BATHA, SH MONTGOMERY, DS DRAKE, RP ESTABROOK, K REMINGTON, BA AF BATHA, SH MONTGOMERY, DS DRAKE, RP ESTABROOK, K REMINGTON, BA TI PRODUCTION OF VERY LARGE, SUB-10TH-CRITICAL PLASMAS FOR LASER-FUSION RESEARCH SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID STIMULATED RAMAN-SCATTERING; BRILLOUIN-SCATTERING; UNDERDENSE PLASMA; 2-PLASMON DECAY; FOIL TARGETS; MU-M; LIGHT; BACKSCATTERING; INSTABILITY; BACKWARD AB The development of a plasma environment that is appropriate for the study of low-gain processes in laser-fusion plasma is reported. These plasmas have long scale lengths, low densities, and no quarter-critical or critical-density surfaces. The plasmas were created by two-sided irradiation of CH foils with 15 kJ of 351 nm laser light. When the peak electron density in the plasma had decayed to about 2 x 10(20) cm-3, the parabolic density profile was estimated to have a full width at half-maximum of 3 mm and the electron temperature was estimated to be 1 keV. Probe lasers of different wavelengths were used to measure the peak electron density via stimulated scattering processes and odd half-harmonic generation. Sufficiently accurate modeling of the laser-irradiation conditions led to improved agreement between the experiment and two-dimensional (2-D) computer simulations. C1 UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616. RP BATHA, SH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,PLASMA PHYS RES INST,LIVERMORE,CA 94550, USA. RI Drake, R Paul/I-9218-2012; OI Drake, R Paul/0000-0002-5450-9844; Montgomery, David/0000-0002-2355-6242 NR 30 TC 9 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD OCT PY 1991 VL 3 IS 10 BP 2898 EP 2905 DI 10.1063/1.859923 PG 8 WC Physics, Fluids & Plasmas SC Physics GA GJ795 UT WOS:A1991GJ79500019 ER PT J AU ZUREK, WH AF ZUREK, WH TI DECOHERENCE AND THE TRANSITION FROM QUANTUM TO CLASSICAL SO PHYSICS TODAY LA English DT Article ID BROWNIAN-MOTION; WAVE PACKET; MECHANICS; OSCILLATOR; ENVIRONMENT; SYSTEM C1 SANTA FE INST,SANTA FE,NM. RP ZUREK, WH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,THEORET ASTROPHYS GRP,LOS ALAMOS,NM 87544, USA. NR 41 TC 1527 Z9 1541 U1 11 U2 106 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 OCT PY 1991 VL 44 IS 10 BP 36 EP 44 DI 10.1063/1.881293 PG 9 WC Physics, Multidisciplinary SC Physics GA GK442 UT WOS:A1991GK44200011 ER PT J AU WULLSCHLEGER, SD OOSTERHUIS, DM HURREN, RG HANSON, PJ AF WULLSCHLEGER, SD OOSTERHUIS, DM HURREN, RG HANSON, PJ TI EVIDENCE FOR LIGHT-DEPENDENT RECYCLING OF RESPIRED CARBON-DIOXIDE BY THE COTTON FRUIT SO PLANT PHYSIOLOGY LA English DT Article ID PISUM-SATIVUM-L; ISOTOPE DISCRIMINATION; POD; PHOTOSYNTHESIS; DISSIPATION; BARLEY; ENERGY; LEAVES; WHEAT; ORGAN AB Conservation of respired CO2 by an efficient recycling mechanism in fruit could provide a significant source of C for yield productivity. However, the extent to which such a mechanism operates in cotton (Gossypium hirsutum L.) is unknown. Therefore, a combination of CO2 exchange, stable C isotope, and chlorophyll (Chl) fluorescence techniques were used to examine the recycling of respired CO2 in cotton fruit. Respiratory CO2 losses of illuminated fruit were reduced 15 to 20% compared with losses for dark-incubated fruit. This light-dependent reduction in CO2 efflux occurred almost exclusively via the fruit's outer capsule wall. Compared with the photosynthetic activity of leaves, CO2 recycling by the outer capsule wall was 35 to 40% as efficient. Calculation of (CO2)-C-14 fixation on a per Chl basis revealed that the rate of CO2 recycling for the capsule wall was 62.2 micromoles (CO2)-C-14 per millimole Chl per second compared with an assimilation rate of 64.6 micromoles (CO2)-C-14 per millimole Chl per second for leaves. During fruit development, CO2 recycling contributed more than 10% of that C necessary for fruit dry weight growth. Carbon isotope analyses (delta-C-13) showed significant differences among the organs examined, but the observed isotopic compositions were consistent with a C3 pathway of photosynthesis. Pulse-modulated Chl fluorescence indicated that leaves and fruit were equally efficient in photochemical and nonphotochemical dissipation of light energy. These studies demonstrated that the cotton fruit possesses a highly efficient, light-dependent CO2 recovery mechanism that aids in the net retention of plant C and, therein, contributes to yield productivity. C1 UNIV ARKANSAS,DEPT RENAL DIS,ALTHEIMER LAB,FAYETTEVILLE,AR 72701. RP WULLSCHLEGER, SD (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. RI Hanson, Paul J./D-8069-2011; Wullschleger, Stan/B-8297-2012 OI Hanson, Paul J./0000-0001-7293-3561; Wullschleger, Stan/0000-0002-9869-0446 NR 25 TC 20 Z9 24 U1 2 U2 3 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD OCT PY 1991 VL 97 IS 2 BP 574 EP 579 DI 10.1104/pp.97.2.574 PG 6 WC Plant Sciences SC Plant Sciences GA GM057 UT WOS:A1991GM05700015 PM 16668437 ER PT J AU ROCK, CD HEATH, TG GAGE, DA ZEEVAART, JAD AF ROCK, CD HEATH, TG GAGE, DA ZEEVAART, JAD TI ABSCISIC ALCOHOL IS AN INTERMEDIATE IN ABSCISIC-ACID BIOSYNTHESIS IN A SHUNT PATHWAY FROM ABSCISIC ALDEHYDE SO PLANT PHYSIOLOGY LA English DT Article ID TOMATO MUTANTS FLACCA; ZEA-MAYS-L; WILTY MUTANTS; ARABIDOPSIS-THALIANA; DEFICIENT MUTANTS; MOLECULAR-OXYGEN; ABA-ALDEHYDE; METABOLISM; XANTHOXIN; ACCUMULATION AB It has previously been shown that the abscisic acid (ABA)-deficient flacca and sitiens mutants of tomato are impaired in ABA-aldehyde oxidation and accumulate trans-ABA-alcohol as a result of the biosynthetic block (IB Taylor, RST Linforth, RJ Al-Naieb, WR Bowman, BA Marples [1988] Plant Cell Environ 11:739-745). Here we report that the flacca and sitiens mutants accumulate trans-ABA and trans-ABA glucose ester and that this accumulation is due to trans-ABA biosynthesis. O-18 labeling of water-stressed wild-type and mutant tomato leaves and analysis of [O-18]ABA by tandem mass spectrometry show that the tomato mutants synthesize a significant percentage of their ABA and trans-ABA as [O-18]ABA with two O-18 atoms in the carboxyl group. We further show, by feeding experiments with [H-2(6)]ABA-alcohol and O-18(2), that this doubly-carboxyl-labeled ABA is synthesized from [O-18]ABA-alcohol with incorporation of molecular oxygen. In vivo inhibition of [H-2(6)]ABA-alcohol oxidation by carbon monoxide establishes the involvement of a P-450 monooxygenase. Likewise, carbon monoxide inhibits the synthesis of doubly-carboxyl-labeled ABA in O-18-labeling experiments. This minor shunt pathway from ABA-aldehyde to ABA-alcohol to ABA operates in all plants examined. For the ABA-deficient mutants impaired in ABA-aldehyde oxidation, this shunt pathway is an important source of ABA and is physiologically significant. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. MICHIGAN STATE UNIV,NIH,MASS SPECTROMETRY FACIL,E LANSING,MI 48824. NR 30 TC 42 Z9 42 U1 0 U2 1 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD OCT PY 1991 VL 97 IS 2 BP 670 EP 676 DI 10.1104/pp.97.2.670 PG 7 WC Plant Sciences SC Plant Sciences GA GM057 UT WOS:A1991GM05700029 PM 16668451 ER PT J AU BOUILLARD, JX GIDASPOW, D AF BOUILLARD, JX GIDASPOW, D TI ON THE ORIGIN OF BUBBLES AND GELDART CLASSIFICATION SO POWDER TECHNOLOGY LA English DT Article ID FLUIDIZATION; GAS; PARTICULATE; PRESSURE; BEHAVIOR; BEDS; JET AB Void propagation equations based only on conservation of mass and the Ergun equation for flow in porous media are sufficient to show that bubbles, which are continuity shocks, will form in a fluidized bed near minimum fluidization for small particles and that voids will disperse for large particles, as for Geldart's Type B and D powders. This is due to the fact that the void propagation velocity increases with the square of the porosity for Type B particles and decreases with porosity for Type D particles. A further approximate analysis involving the elastic solids stress between the particles shows the existence of a minimum bubbling velocity and hence provides a rational explanation for the boundary between Type A and B particles. This approximate analysis is further extended to the study of bubbling regimes at low and high fluidizing pressures. C1 IIT,DEPT CHEM ENGN,CHICAGO,IL 60616. RP BOUILLARD, JX (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 34 TC 15 Z9 15 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0032-5910 J9 POWDER TECHNOL JI Powder Technol. PD OCT PY 1991 VL 68 IS 1 BP 13 EP 22 DI 10.1016/0032-5910(91)80059-R PG 10 WC Engineering, Chemical SC Engineering GA GH215 UT WOS:A1991GH21500002 ER PT J AU BOUILLARD, JX LYCZKOWSKI, RW AF BOUILLARD, JX LYCZKOWSKI, RW TI ON THE EROSION OF HEAT-EXCHANGER TUBE BANKS IN FLUIDIZED-BED COMBUSTORS SO POWDER TECHNOLOGY LA English DT Article AB Erosion (usually referred to as metal wastage) of heat exchanger tube banks in bubbling atmospheric and pressurized fluidized beds is a serious issue that may affect their reliability and economics. A simplified version of the comprehensive monolayer energy dissipation (MED) erosion model, developed by us earlier, is presented. This study illustrates the application and usefulness of this simplified MED erosion model to quickly and easily produce trends and dependencies upon independent parameters. This version can easily fit on a pocket calculator or desktop personal computer. Predicted trends of erosion rate dependency upon the particle diameter, the fluidizing velocity and bed porosity using this model are discussed. Main fluidization variables are introduced in this erosion model by interpreting the solids-fluid interphase drag as the principal means of potential erosion. This simplified MED erosion model is compared with three other erosion models: the more comprehensive MED erosion model, the Finnie impaction erosion model, and the combined ductile-brittle Neilson-Gilchrist (N-G) erosion model. The simplified MED erosion model is shown to agree reasonably well with the maximum erosion data obtained experimentally at the Grimethorpe cold model facility of the Coal Research Establishment. A two-dimensional fluidized-bed geometry embodying three immersed tubes, which represents a generic approximation of the Coal Research Establishment cold models, is used to compare erosion model predictions. Detailed hydrodynamic calculations for this bed geometry were performed using the FLUFIX computer code and were used as inputs to the four erosion models. The comprehensive MED, the Finnie and the N-G erosion models predict an order-of-magnitude agreement with each other and with limited erosion experimental data. Good agreement is obtained between the relative trends predicted by the simplified and comprehensive versions of the MED erosion model. RP BOUILLARD, JX (reprint author), ARGONNE NATL LAB,DIV ENERGY SYST,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 24 TC 13 Z9 13 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0032-5910 J9 POWDER TECHNOL JI Powder Technol. PD OCT PY 1991 VL 68 IS 1 BP 37 EP 51 DI 10.1016/0032-5910(91)80062-N PG 15 WC Engineering, Chemical SC Engineering GA GH215 UT WOS:A1991GH21500005 ER PT J AU MILLER, EK AF MILLER, EK TI SOLVING BIGGER PROBLEMS - BY DECREASING THE OPERATION COUNT AND INCREASING THE COMPUTATION BANDWIDTH SO PROCEEDINGS OF THE IEEE LA English DT Article AB The purpose of this discussion is to illustrate the computational complexity of modeling large (in wavelengths) electromagnetic problems and to suggest some ways by which the computational requirements can be reduced. In particular, we make the point that simply relying on faster computers for increasing the size and complexity of problems that can be modeled is less effective than might be anticipated from the raw increase in computer throughput, a factor of about a million, that has occurred between the UNIVAC-1 and the CRAY2. This is because the required floating-point operation (FLOP) count for integral-equation (IE) and differential-equation (DE) models grows with frequency, f, as f(x), where 3 less-than-or-equal-to x less-than-or-equal-to 9, which means that increasing f by a factor of 10 for a given problem can require from 1000 to 1 000 000 000 more FLOP's. We suggest that rather than depending on faster computers alone, various analytical and numerical alternatives are needed for reducing the overall FLOP count required to acquire the information desired, some possibilities for which are discussed in this article. RP MILLER, EK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,INSTRUMENTAT GRP,GRP MEE-3,LOS ALAMOS,NM 87545, USA. NR 28 TC 9 Z9 9 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 0018-9219 J9 P IEEE JI Proc. IEEE PD OCT PY 1991 VL 79 IS 10 BP 1493 EP 1504 DI 10.1109/5.104224 PG 12 WC Engineering, Electrical & Electronic SC Engineering GA GU211 UT WOS:A1991GU21100017 ER PT J AU METROPOLIS, N ROTA, GC STEIN, JA AF METROPOLIS, N ROTA, GC STEIN, JA TI THEORY OF SYMMETRY CLASSES SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article AB Although a great deal of work has gone into construction of the irreducible representations of the symmetric group SIGMA-n (and of the general linear group) a simple, intuitive characterization of the symmetry classes is missing. Relying on a systematic distinction between permutations of variables and permutations of places, we provide two such characterizations, showing that elements belonging to any such symmetry class can be described in one of two ways: (i) as the solutions of explicitly given (though not independent) sets of linear equations or (ii) as linear combinations of "simple" elements of a given symmetry class, a simple element being a generalization to an arbitrary symmetry class of the notion of a decomposable skew-symmetric tensor. C1 MIT,DEPT MATH,LOS ALAMOS NATL LAB,CAMBRIDGE,MA 02139. CALIF STATE UNIV SAN BERNARDINO,DEPT MATH,SAN BERNARDINO,CA 92407. RP METROPOLIS, N (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD OCT PY 1991 VL 88 IS 19 BP 8415 EP 8419 DI 10.1073/pnas.88.19.8415 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GH805 UT WOS:A1991GH80500028 PM 11607215 ER PT J AU BOND, VP BENARY, V SONDHAUS, CA AF BOND, VP BENARY, V SONDHAUS, CA TI A DIFFERENT PERCEPTION OF THE LINEAR, NONTHRESHOLD HYPOTHESIS FOR LOW-DOSE IRRADIATION SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE RADIATION PROTECTION; LOW-LEVEL RADIATION; RADIOEPIDEMIOLOGY; THRESHOLDS ID QUALITY AB Two equally useful dosimetric quantities, both of which are called dose, are used in toxicology. With radiation measurement, only one-the energy per unit mass D-is called dose. The other-the total energy in the irradiated system-is here distinguished from D by assigning it the name collective energy, epsilon. The collective energy is a more complete statement of dose because it is the product of the energy concentration D and the mass irradiated m. Especially in radioepidemiology, in which epsilon is the total energy imparted to all persons irradiated, the quantity m must be specified because it is situation specific and thus highly variable. At present, radioepidemiological dose-response curves are given only in terms of the toxicological model-i.e., the fraction (probability) of radiation-attributable cancers occurring as a function of D. Because this relation does not involve the number of persons at each value of D, it fosters the illusion that any dose, no matter how small, can result in cancer. However, we show that if the dose-response relationship is expressed in terms of the absolute number of attributable cancers as a function of epsilon, cancer occurs, on average, only if the collective energy exceeds a relatively large minimum value, the magnitude of which will be estimated. Therefore, we conclude that the nonthreshold aspect of the linear hypothesis is misleading and quite probably invalid. For example, in or around a facility in which exposure of humans to relatively low values of D occurs, attributable cancers are most unlikely to appear unless the epsilon to the irradiated population exceeds this minimum value. C1 TEL AVIV UNIV,SCH PHYS,IL-69456 TEL AVIV,ISRAEL. USA,SCH CHEM,BRADLEY RADIOL LAB,FT MCCLELLAN,AL 36205. RP BOND, VP (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 9 TC 14 Z9 15 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 OCT PY 1991 VL 88 IS 19 BP 8666 EP 8670 DI 10.1073/pnas.88.19.8666 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GH805 UT WOS:A1991GH80500079 PM 1924328 ER PT J AU KURIYAN, J KONG, XP KRISHNA, TSR SWEET, RM MURGOLO, NJ FIELD, H CERAMI, A HENDERSON, GB AF KURIYAN, J KONG, XP KRISHNA, TSR SWEET, RM MURGOLO, NJ FIELD, H CERAMI, A HENDERSON, GB TI X-RAY STRUCTURE OF TRYPANOTHIONE REDUCTASE FROM CRITHIDIA-FASCICULATA AT 2.4-A RESOLUTION SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE GLUTATHIONE REDUCTASE; OXIDATIVE STRESS; TRYPANOSOMIASIS; PROTEIN CRYSTALLOGRAPHY; DRUG DESIGN ID GLUTATHIONE-REDUCTASE; REFINEMENT; TRYPANOSOMIASIS; CRYSTALLOGRAPHY; PURIFICATION; STRATEGY; DETECTOR; BINDING; ENZYME AB Trypanosomes and related protozoan parasites lack glutathione reductase and possess instead a closely related enzyme that serves as the reductant of a bis(glutathione)-spermidine conjugate, trypanothione. The human and parasite enzymes have mutually exclusive substrate specificities, providing a route for the design of therapeutic agents by specific inhibition of the parasite enzyme. We report here the three-dimensional structure of trypanothione reductase from Crithidia fasciculata and show that it closely resembles the structure of human glutathione reductase. In particular, the core structure surrounding the catalytic machinery is almost identical in the two enzymes. However, significant differences are found at the substrate binding sites. A cluster of basic residues in glutathione reductase is replaced by neutral, hydrophobic, or acidic residues in trypanothione reductase, consistent with the nature of the spermidine linkage and the change in overall charge of the substrate from -2 to +1, respectively. The binding site is more open in trypanothione reductase due to rotations of about 4-degrees in the domains that form the site, with relative shifts of as much as 2-3 angstrom in residue positions. These results provide a detailed view of the residues that can interact with potential inhibitors and complement previous modeling and mutagenesis studies on the two enzymes. C1 ROCKEFELLER UNIV,MOLEC BIOPHYS LAB,NEW YORK,NY 10021. ROCKEFELLER UNIV,MED BIOCHEM LAB,NEW YORK,NY 10021. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RP KURIYAN, J (reprint author), ROCKEFELLER UNIV,HOWARD HUGHES MED INST,1230 YORK AVE,NEW YORK,NY 10021, USA. FU NIAID NIH HHS [AI19428, AI26784]; NIGMS NIH HHS [GM45547] NR 29 TC 109 Z9 109 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD OCT PY 1991 VL 88 IS 19 BP 8764 EP 8768 DI 10.1073/pnas.88.19.8764 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GH805 UT WOS:A1991GH80500099 PM 1924336 ER PT J AU BARTLETT, EJ WOLKIN, A BRODIE, JD LASKA, EM WOLF, AP SANFILIPO, M AF BARTLETT, EJ WOLKIN, A BRODIE, JD LASKA, EM WOLF, AP SANFILIPO, M TI IMPORTANCE OF PHARMACOLOGICAL CONTROL IN PET STUDIES - EFFECTS OF THIOTHIXENE AND HALOPERIDOL ON CEREBRAL GLUCOSE-UTILIZATION IN CHRONIC-SCHIZOPHRENIA SO PSYCHIATRY RESEARCH-NEUROIMAGING LA English DT Article DE POSITRON EMISSION TOMOGRAPHY; NEUROLEPTICS; DOPAMINE-D2 RECEPTORS; BASAL GANGLIA; FRONTAL LOBE; DEOXYGLUCOSE ID POSITRON EMISSION TOMOGRAPHY; METABOLIC-RATE; BRAIN; NEUROLEPTICS; HUMANS AB This study compares the effects of two neuroleptic drugs with different pharmacologic characteristics (thiothixene and haloperidol) on cerebral glucose utilization in chronic schizophrenic inpatients. Positron emission tomographic (PET) scans were obtained from all subjects in a neuroleptic-free condition and again after 4-6 weeks of neuroleptic treatment. Eight subjects were treated with thiothixene and 12 with haloperidol. Thiothixene and haloperidol had different metabolic effects. For example, all thiothixene-treated subjects showed increased whole brain glucose utilization; all but one haloperidol-treated subject showed decreased utilization. Different patterns of relative prefrontal and striatal metabolism were also observed. These results highlight the importance of controlling for the effects of neuroleptic treatment and indicate the difficulty of interpreting data from studies with complex or poorly defined drug regimens. C1 NYU MED CTR,DEPT PSYCHIAT,550 1ST AVE,NEW YORK,NY 10016. NATHAN S KLINE INST PSYCHIAT RES,NEW YORK,NY. VET ADM MED CTR,SERV PSYCHIAT,NEW YORK,NY 10010. BROOKHAVEN NATL LAB,DEPT CHEM,CYCLOTRON PET PROGRAM,UPTON,NY 11973. FU NIMH NIH HHS [MH-15381, MH-42959]; NINDS NIH HHS [NS-15638] NR 18 TC 52 Z9 52 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0925-4927 J9 PSYCHIAT RES-NEUROIM JI Psychiatry Res. Neuroimaging PD OCT PY 1991 VL 40 IS 2 BP 115 EP 124 DI 10.1016/0925-4927(91)90003-9 PG 10 WC Clinical Neurology; Neuroimaging; Psychiatry SC Neurosciences & Neurology; Psychiatry GA GM916 UT WOS:A1991GM91600003 PM 1763142 ER PT J AU ALPEN, EL AF ALPEN, EL TI THE HISTORICAL BACKGROUND FOR LARGE-ANIMAL STUDIES WITH NEUTRONS OF VARIOUS ENERGIES SO RADIATION RESEARCH LA English DT Article C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP ALPEN, EL (reprint author), UNIV CALIF BERKELEY,DIV BIOPHYS,BERKELEY,CA 94720, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S37 EP S41 DI 10.2307/3577999 PG 5 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400007 PM 1924745 ER PT J AU BOND, VP CARSTEN, AL BULLIS, J ROTH, SP AF BOND, VP CARSTEN, AL BULLIS, J ROTH, SP TI SEVERITY OF ORGAN INJURY AS A PREDICTOR OF ACUTE MORTALITY FOR DISPARATE PATTERNS OF ABSORBED DOSE DISTRIBUTION SO RADIATION RESEARCH LA English DT Article RP BOND, VP (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 3 TC 5 Z9 5 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S9 EP S11 DI 10.2307/3577995 PG 3 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400003 PM 1924756 ER PT J AU CARNES, BA GRAHN, D AF CARNES, BA GRAHN, D TI ISSUES ABOUT NEUTRON EFFECTS - THE JANUS PROGRAM SO RADIATION RESEARCH LA English DT Article ID REGRESSION-MODELS RP CARNES, BA (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. NR 25 TC 8 Z9 8 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S141 EP S146 DI 10.2307/3578017 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400025 PM 1924741 ER PT J AU GRDINA, DJ WRIGHT, BJ CARNES, BA AF GRDINA, DJ WRIGHT, BJ CARNES, BA TI PROTECTION BY WR-151327 AGAINST LATE-EFFECT DAMAGE FROM FISSION-SPECTRUM NEUTRONS SO RADIATION RESEARCH LA English DT Article ID WHOLE-BODY EXPOSURE; CO-60 GAMMA-RAY; V79 CELLS; CHEMICAL PROTECTION; IONIZING-RADIATION; INDUCED MUTATIONS; WR1065; MICE; WR-2721; LOCUS C1 UNIV CHICAGO,DEPT RADIAT & CELLULAR ONCOL,CHICAGO,IL 60637. RP GRDINA, DJ (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. FU NCI NIH HHS [CA-37435] NR 24 TC 10 Z9 10 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S124 EP S127 DI 10.2307/3578014 PG 4 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400022 PM 1924738 ER PT J AU HANSON, WR GRDINA, DJ AF HANSON, WR GRDINA, DJ TI MISOPROSTOL, A PGE1 ANALOG, PROTECTS MICE FROM FISSION-NEUTRON INJURY SO RADIATION RESEARCH LA English DT Article ID HEMATOPOIETIC STEM-CELLS; PROSTAGLANDIN-E-2 INDUCES RADIOPROTECTION; CELLULAR RADIOSENSITIVITY INVITRO; INTESTINAL RADIATION PROTECTION; MAMMALIAN-CELLS; 16,16-DIMETHYL PROSTAGLANDIN-E2; MURINE INTESTINE; SURVIVAL; BIOSYNTHESIS; COMBINATION C1 EDWARD HINES VET ADM MED CTR,HINES,IL 60141. ARGONNE NATL LAB,DIV BIOL & ENVIRONM RES,ARGONNE,IL 60439. RP HANSON, WR (reprint author), LOYOLA UNIV,LOYOLA HINES DEPT RADIOTHERAPY,114B,HINES,IL 60141, USA. FU NCI NIH HHS [CA 37435] NR 41 TC 4 Z9 4 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S12 EP S17 DI 10.2307/3577996 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400004 PM 1656482 ER PT J AU SEED, TM KASPAR, LV AF SEED, TM KASPAR, LV TI PROBING ALTERED HEMATOPOIETIC PROGENITOR CELLS OF PRELEUKEMIC DOGS WITH JANUS FISSION NEUTRONS SO RADIATION RESEARCH LA English DT Article ID MYELOPROLIFERATIVE DISEASE; GAMMA-IRRADIATION; RADIOSENSITIVITY; ULTRASTRUCTURE RP SEED, TM (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,RADIAT HEMATOL GRP,ARGONNE,IL 60439, USA. NR 24 TC 3 Z9 3 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 1991 VL 128 IS 1 SU S BP S81 EP S86 DI 10.2307/3578007 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA GK944 UT WOS:A1991GK94400015 PM 1924754 ER PT J AU BARALE, JC LANGSLEY, G MANGEL, WF BRAUNBRETON, C AF BARALE, JC LANGSLEY, G MANGEL, WF BRAUNBRETON, C TI MALARIAL PROTEASES - ASSIGNMENT OF FUNCTION TO ACTIVITY SO RESEARCH IN IMMUNOLOGY LA English DT Article ID PLASMODIUM-FALCIPARUM MEROZOITES; SURFACE-ANTIGEN; PARASITOPHOROUS VACUOLE; ERYTHROCYTE INVASION; HOST ERYTHROCYTE; INHIBITORS; PARASITE; PROTEINASE; KNOWLESI; STAGE C1 INST PASTEUR,DEPT IMMUNOL,UNITE PARASITOL EXPTL,F-75724 PARIS 15,FRANCE. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. NR 53 TC 7 Z9 7 U1 0 U2 0 PU EDITIONS SCIENTIFIQUES ELSEVIER PI PARIS CEDEX 15 PA 141 RUE JAVEL, 75747 PARIS CEDEX 15, FRANCE SN 0923-2494 J9 RES IMMUNOL JI Res. Immunol. PD OCT PY 1991 VL 142 IS 8 BP 672 EP 681 DI 10.1016/0923-2494(91)90148-C PG 10 WC Immunology SC Immunology GA GZ186 UT WOS:A1991GZ18600011 PM 1817297 ER PT J AU SMITH, HV ALLISON, P SCHNEIDER, JD SAADATMAND, K AF SMITH, HV ALLISON, P SCHNEIDER, JD SAADATMAND, K TI SPATIAL DISTRIBUTIONS OF THE EMITTING SPECIES IN A PENNING SURFACE-PLASMA SOURCE SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Using optical spectroscopy we study the spatial and temporal distributions of the H-alpha, Cs I(4555 angstrom), Cs II(4604 angstrom), and Mo I(3903 angstrom) emission lines in a Penning surface-plasma source (SPS). A diagnostic slit exposes the entire SPS discharge gap either parallel or perpendicular to the magnetic field. The spatial and temporal distributions of the emitting species are recorded using a 1-m monochromator. In addition, the visible light and the H-alpha and Cs II(4604 angstrom) spatial distributions are recorded with a video camera. The cesium atomic and ionic light, and the molybdenum atomic light, is strongly concentrated near the cathodes; the visible light and the H-alpha light is almost uniform in both directions. Electron-impact ionization of atoms sputtered from the cathodes and the return of the ions to the cathodes by residual plasma fields is probably the mechanism which concentrates cesium near the cathodes. The Cs0 mean free path is estimated to be 16 and 0.43 mm for 2 and 400 A discharges, respectively. C1 GRUMMAN CORP RES CTR,BETHPAGE,NY 11714. RP SMITH, HV (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 7 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 1991 VL 62 IS 10 BP 2307 EP 2313 DI 10.1063/1.1142290 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA GH598 UT WOS:A1991GH59800001 ER PT J AU SHERMAN, JD SMITH, HV GEISIK, C ALLISON, P AF SHERMAN, JD SMITH, HV GEISIK, C ALLISON, P TI H- TEMPERATURE-MEASUREMENTS BY A SLIT DIAGNOSTIC-TECHNIQUE SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PLASMA AB H- ion beams are extracted at 5-25 kV from a long, narrow slit on a Penning surface-plasma source (the 8X source). The extraction geometry produces negligible transverse electric fields (focusing effects) along the slit length. Therefore, the ion angular spread reflects the distribution of ion energies at the plasma surface. The angular distributions are measured with an electric-sweep emittance scanner whose slits are oriented normal to the long dimension of the emission slit. The nearly Maxwellian angular distributions measured over the central portions of the ribbon beam give kT(H-) of 0.1-0.2 eV for a 2-A dc discharge and 0.8-1.0 eV for 350-500 A pulsed discharges. This diagnostic technique has sufficient position resolution to allow measurement of the kT(H-) spatial distributions. It also allows study of the kT(H-) dependencies on ion source parameters (e.g., increasing the H-2 gas flow lowers kT(H-)). RP SHERMAN, JD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 10 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 1991 VL 62 IS 10 BP 2314 EP 2317 DI 10.1063/1.1142291 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA GH598 UT WOS:A1991GH59800002 ER PT J AU COHEN, BI COHEN, RH NEVINS, WM ROGNLIEN, TD AF COHEN, BI COHEN, RH NEVINS, WM ROGNLIEN, TD TI THEORY OF FREE-ELECTRON-LASER HEATING AND CURRENT DRIVE IN MAGNETIZED PLASMAS SO REVIEWS OF MODERN PHYSICS LA English DT Article ID CYCLOTRON CURRENT DRIVE; WAVE CURRENT DRIVE; AMPLITUDE ELECTROMAGNETIC-WAVE; ORDINARY-MODE PROPAGATION; INTENSE MICROWAVE PULSES; PARAMETRIC-INSTABILITIES; TOKAMAK PLASMAS; PARTICLE-ACCELERATION; SIDEBAND INSTABILITY; PONDEROMOTIVE FORCE AB The introduction of a powerful new microwave source, the free-electron laser, provides new opportunities for novel heating and current-drive schemes to be used in toroidal fusion devices. This high-power, pulsed source has a number of technical advantages for these applications, and its use is predicted to lead to improved current-drive efficiencies and opacities in reactor-grade fusion plasmas in specific cases. The Microwave Tokamak Experiment at the Lawrence Livermore National Laboratory will provide a test for some of these new heating and current-drive schemes. Although the motivation for much of this research has derived from the application of a free-electron laser to the heating of a tokamak plasma at a frequency near the electron cyclotron frequency, the underlying physics, i.e., the highly nonlinear interaction of an intense, pulsed, coherent electromagnetic wave with an electron in a magnetized plasma including relativistic effects, is of general interest. Other relevant applications include ionospheric modification by radio-frequency waves, high-energy electron accelerators, and the propagation of intense, pulsed electromagnetic waves in space and astrophysical plasmas. This review reports recent theoretical progress in the analysis and computer simulation of the absorption and current drive produced by intense pulses, and of the possible complications that may arise, e.g., parametric instabilities, nonlinear self-focusing, trapped-particle sideband instability, and instabilities of the heated plasma. RP COHEN, BI (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 133 TC 39 Z9 39 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD OCT PY 1991 VL 63 IS 4 BP 949 EP 990 DI 10.1103/RevModPhys.63.949 PG 42 WC Physics, Multidisciplinary SC Physics GA GL695 UT WOS:A1991GL69500005 ER PT J AU UNSEREN, MA AF UNSEREN, MA TI RIGID BODY DYNAMICS AND DECOUPLED CONTROL ARCHITECTURE FOR 2 STRONGLY INTERACTING MANIPULATORS SO ROBOTICA LA English DT Article DE 2 MANIPULATORS; RIGID BODY DYNAMICS; CONTROL ARCHITECTURE; REDUCED ORDER MODEL; COMPOSITE CONTROLLER AB A rigid body dynamical model and control architecture are developed for the closed chain motion of two structurally dissimilar manipulators holding a rigid object in a three-dimensional workspace. The model is first developed in the joint space and then transformed to obtain reduced order equations of motion and a separate set of equations describing the behavior of the generalized contact forces. The problem of solving the joint space and reduced order models for the unknown variables is discussed. A new control architecture consisting of the sum of the outputs of a primary and secondary controller is suggested which, according to the model, decouples the force- and position-controlled degrees of freedom during motion of the system. The proposed composite controller enables the designer to develop independent, non-interacting control laws for the force and position control of the complex closed chain system. RP UNSEREN, MA (reprint author), OAK RIDGE NATL LAB,CTR ENGN SYST ADV RES,BLDG 6025,MS 6364,POB 2008,OAK RIDGE,TN 37831, USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0263-5747 J9 ROBOTICA JI Robotica PD OCT-DEC PY 1991 VL 9 BP 421 EP 430 PN 4 PG 10 WC Robotics SC Robotics GA GL675 UT WOS:A1991GL67500008 ER PT J AU MACCRACKEN, MC AF MACCRACKEN, MC TI KUWAITS DARK DAYS SO SCIENTIFIC AMERICAN LA English DT Letter RP MACCRACKEN, MC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ATMOSPHER & GEOPHYS SCI,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD OCT PY 1991 VL 265 IS 4 BP 12 EP 12 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GL869 UT WOS:A1991GL86900003 ER PT J AU TORTORELLI, PF KEISER, JR AF TORTORELLI, PF KEISER, JR TI THE USE OF DEPTH-SENSING SUBMICRON INDENTATION TESTING TO CHARACTERIZE THE MECHANICAL-BEHAVIOR OF THIN OXIDE SCALES SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID CRACKING RP TORTORELLI, PF (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Tortorelli, Peter/E-2433-2011 NR 19 TC 10 Z9 10 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 OCT PY 1991 VL 25 IS 10 BP 2339 EP 2344 DI 10.1016/0956-716X(91)90026-W PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GH241 UT WOS:A1991GH24100026 ER PT J AU YOO, MH FU, CL AF YOO, MH FU, CL TI ON THE THEORY OF CLEAVAGE FRACTURE IN B2-TYPE ALUMINIDES - FEAL AND NIAL SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID ALLOYS RP YOO, MH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 17 TC 30 Z9 33 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD OCT PY 1991 VL 25 IS 10 BP 2345 EP 2350 DI 10.1016/0956-716X(91)90027-X PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GH241 UT WOS:A1991GH24100027 ER PT J AU SANDERS, PG SIKKA, VK HOWELL, CR BALDWIN, RH AF SANDERS, PG SIKKA, VK HOWELL, CR BALDWIN, RH TI A PROCESSING METHOD TO REDUCE THE ENVIRONMENTAL-EFFECT IN FE3AL-BASED ALLOYS SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID CHROMIUM; FE3AL RP SANDERS, PG (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 9 TC 18 Z9 19 U1 0 U2 3 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 OCT PY 1991 VL 25 IS 10 BP 2365 EP 2369 DI 10.1016/0956-716X(91)90031-U PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA GH241 UT WOS:A1991GH24100031 ER PT J AU BECHTOLD, JK MARGOLIS, SB AF BECHTOLD, JK MARGOLIS, SB TI NONLINEAR HYDRODYNAMIC STABILITY AND SPINNING DEFLAGRATION OF LIQUID PROPELLANTS SO SIAM JOURNAL ON APPLIED MATHEMATICS LA English DT Article DE NONLINEAR HYDRODYNAMIC STABILITY; BIFURCATION; LIQUID PROPELLANT; DOUBLE ZERO EIGENVALUE; AMPLITUDE EQUATIONS ID CELLULAR FLAMES; BIFURCATION; INSTABILITIES; PROPAGATION; COMBUSTION; CONVECTION; WAVES AB Considered is a dynamic model of liquid propellant combustion that generalizes the classical model due to Landau. In appropriate parameter regimes, this model exhibits the well-known phenomenon of hydrodynamic (Landau) instability, in which steady planar deflagration is unstable to steady, but nonplanar (cellular), modes of combustion. In a cylindrical geometry, there exist special values of the radius such that the basic solution simultaneously loses stability to two cellular modes at critical values of a parameter that determines the sensitivity of the reaction rate to the local pressure field. A nonlinear stability analysis in the neighborhood of certain members of this sequence of double eigenvalues then leads to the prediction, by either one or the other of two methods, of secondary and tertiary branching of orbitally stable, spinning deflagration waves. RP BECHTOLD, JK (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 22 TC 4 Z9 4 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1399 J9 SIAM J APPL MATH JI SIAM J. Appl. Math. PD OCT PY 1991 VL 51 IS 5 BP 1356 EP 1379 DI 10.1137/0151068 PG 24 WC Mathematics, Applied SC Mathematics GA GJ951 UT WOS:A1991GJ95100010 ER PT J AU ASHBY, SF AF ASHBY, SF TI MINIMAX POLYNOMIAL PRECONDITIONING FOR HERMITIAN LINEAR-SYSTEMS SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE CONJUGATE GRADIENT METHODS; POLYNOMIAL PRECONDITIONING; MINIMAX APPROXIMATION; ADAPTIVE PROCEDURE ID CONJUGATE-GRADIENT METHODS; ITERATIVE METHODS; ALGEBRAIC EQUATIONS; MATRIX AB This paper explores the use of polynomial preconditioning for Hermitian positive definite and indefinite linear systems Ax = b. Unlike preconditioners based on incomplete factorizations, polynomial preconditioners are easy to employ and well suited to vector and/or parallel architectures. It is shown that any polynomial iterative method may be used to define a preconditioning polynomial, and that the optimum polynomial preconditioner is obtained from a minimax approximation problem. A variety of preconditioning polynomials are then surveyed, including the Chebyshev, de Boor and Rice, Grcar, and bilevel polynomials. Adaptive procedures for each of these polynomials are also discussed, and it is shown that the new bilevel polynomial is particularly well suited for use in adaptive CG algorithms. RP ASHBY, SF (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LAWRENCE LIVERMORE NATL LAB,COMP & MATH RES DIV,POB 808,LIVERMORE,CA 94551, USA. NR 40 TC 13 Z9 14 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD OCT PY 1991 VL 12 IS 4 BP 766 EP 789 DI 10.1137/0612059 PG 24 WC Mathematics, Applied SC Mathematics GA GG460 UT WOS:A1991GG46000013 ER PT J AU GOLDSTEIN, CI AF GOLDSTEIN, CI TI PRECONDITIONING SINGULARITY PERTURBED ELLIPTIC AND PARABOLIC PROBLEMS SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE SINGULARLY PERTURBED ELLIPTIC AND PARABOLIC PROBLEMS; PRECONDITIONERS; CONDITION NUMBER; NORM EQUIVALENCE ID BOUNDARY-VALUE-PROBLEMS; WAVE-PROPAGATION; EQUATIONS; CONVERGENCE AB The goal of this paper is to investigate methods for preconditioning the system of linear equations that arises from a discretization of singularly perturbed, multidimensional elliptic and parabolic problems. For the problems under consideration, it is important to investigate the conditioning of the resulting system as a function of certain parameters, K and K1, multiplying the zeroth- and first-order derivative terms in the differential operator. Certain constraints relating K or K1 to the gridsize h are imposed for reasons of stability and accuracy of the numerical solution. The analysis involves estimating the condition number kappa(L(h)1(-1) L(h)2) in terms of K and K1, where L(h)1 and L(h)2 are finite element discretizations of two singularly perturbed elliptic operators. It is shown how to construct preconditioning operators such that the condition number of the preconditioned system of equations is bounded as the number of unknowns increases and, at worst, grows slowly as K and K1 increase. The results are applied to elliptic and parabolic convection-diffusion models, as well as two-dimensional Helmholtz problems and "parabolic approximations" of three-dimensional Helmholtz problems. Numerical results are presented illustrating the theory. RP GOLDSTEIN, CI (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV MATH SCI,UPTON,NY 11973, USA. NR 35 TC 5 Z9 5 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD OCT PY 1991 VL 28 IS 5 BP 1386 EP 1418 DI 10.1137/0728072 PG 33 WC Mathematics, Applied SC Mathematics GA GH607 UT WOS:A1991GH60700008 ER PT J AU FISHER, RA WOODFIELD, BF KIM, S PHILLIPS, NE TAILLEFER, L GIORGI, AL SMITH, JL AF FISHER, RA WOODFIELD, BF KIM, S PHILLIPS, NE TAILLEFER, L GIORGI, AL SMITH, JL TI SPECIFIC-HEAT OF UPT3 IN THE VICINITY OF THE ANTIFERROMAGNETIC ORDERING AT 5 K SO SOLID STATE COMMUNICATIONS LA English DT Article ID FERMION SUPERCONDUCTOR UPT3; SPIN AB Specific-heat data in the 0.3 to 20 K region for two high-quality UPt3 samples are analyzed with emphasis on the 4-10 K region. It is concluded that no effect associated with antiferromagnetic ordering has been observed, and an upper limit of the order of 0.1% for such an effect is deduced. The results are compared with earlier measurements in the vicinity of the Neel temperature, 5 K. C1 CNRS,LAB MAGNETISME LOUIS NEEL,F-38042 GRENOBLE,FRANCE. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP FISHER, RA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 11 TC 18 Z9 18 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD OCT PY 1991 VL 80 IS 4 BP 263 EP 266 DI 10.1016/0038-1098(91)90020-V PG 4 WC Physics, Condensed Matter SC Physics GA GQ927 UT WOS:A1991GQ92700004 ER PT J AU GORETTA, KC KULLBERG, ML BAR, D RISCH, GA ROUTBORT, JL AF GORETTA, KC KULLBERG, ML BAR, D RISCH, GA ROUTBORT, JL TI FRACTURE-TOUGHNESS OF YBA2CU3OX CONTAINING Y2BACUO5 AND ZRO2 SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID SUPERCONDUCTING PROPERTIES; MECHANICAL-PROPERTIES; ADDITIONS; SUBSTRATE; OXIDE; FILMS AB Tetragonal ZrO2 particles have been added to superconducting YBa2Cu3Ox (123) to improve its fracture toughness (K(IC)). Reactions between the ZrO2 and 123 prevented the ZrO2 from providing significant toughening. A sol-gel coating of Y2BaCuO5 (211) on the ZrO2 particles minimized the deleterious reactions. Addition of 20 mol% ZrO2 coated with 211 yielded a 123 composite with a K(IC) of 4.5 MPa m0.5. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP GORETTA, KC (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 27 TC 19 Z9 19 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD OCT PY 1991 VL 4 IS 10 BP 544 EP 547 DI 10.1088/0953-2048/4/10/006 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA GV523 UT WOS:A1991GV52300006 ER PT J AU BREMER, PJ GEESEY, GG DRAKE, B JOLLEY, JG HANKINS, MR AF BREMER, PJ GEESEY, GG DRAKE, B JOLLEY, JG HANKINS, MR TI CHARACTERIZATION OF A THIN COPPER FILM TO INVESTIGATE MICROBIAL BIOFILM FORMATION SO SURFACE AND INTERFACE ANALYSIS LA English DT Article ID INTERFACIAL PHENOMENA; CORROSION AB Copper films, 6.7 nm nominal thickness, deposited by physical vapor deposition on germanium substrates appeared as coalescing aggregates of copper atoms when evaluated by atomic force microscopy. Evaluation of the Cu thin film by x-ray photoelectron spectroscopy indicated that the Cu at the surface of the film had the character of a 1 + oxidation state. These features were not significantly changed when the Cu thin film was exposed to ethylene oxide. No Ge signal was detectable prior to XPS depth profiling through the Cu thin film, indicating that the film was continuous. When films of this thickness were deposited on a cylindrical Ge internal reflection element and subsequently submerged in an aqueous medium, there was sufficient transmission of infra-red radiation through the Cu to obtain a significant water absorption band at 1640 cm-1. The intensity of the water absorption band was found to be very sensitive to changes in thickness of the copper thin film. This feature can be used to study the effect of microbial biofilms and their products on the integrity of oxidized copper surfaces in aqueous environments. C1 SCANNING PROBE MICROSCOPE LAB SERV,IMAGING SERV,TRUCKEE,CA 96162. EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. RP BREMER, PJ (reprint author), MONTANA STATE UNIV,COLL ENGN,BOZEMAN,MT 59717, USA. NR 16 TC 8 Z9 8 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD OCT PY 1991 VL 17 IS 11 BP 767 EP 772 DI 10.1002/sia.740171104 PG 6 WC Chemistry, Physical SC Chemistry GA GM270 UT WOS:A1991GM27000003 ER PT J AU KANG, HC FLYNNSANDERS, DK THIEL, PA EVANS, JW AF KANG, HC FLYNNSANDERS, DK THIEL, PA EVANS, JW TI DIFFRACTION PROFILE ANALYSIS FOR EPITAXIAL-GROWTH ON FCC(100) SUBSTRATES - DIFFUSIONLESS MODELS SO SURFACE SCIENCE LA English DT Article ID ENERGY-ELECTRON-DIFFRACTION; THIN-FILM GROWTH; STEPPED SURFACES; INTENSITY OSCILLATIONS; ATOMIC CORRELATIONS; SITE GEOMETRY; INTERFACES; PT/PD(100); DEFECTS; LAYERS AB We develop a kinematic theory to determine surface-sensitive diffracted intensity profiles for epitaxial growth on fcc(100) substrates. On such surfaces, atoms adsorb in fourfold hollow sites (thereby continuing the fcc lattice) rather than in on-top sites (which would create a simple cubic lattice). In a kinematic theory, the "scattering units" are most appropriately taken as vertical columns of atoms, and multiple-scattering between these is ignored. For fcc growth, the tops of these columns are exposed to various degrees, so differing scattering factors are naturally assigned. For systems with weak short-range order, this produces significant differences from behavior analyzed previously for simple cubic geometries. For example, layer-by-layer growth with random partially filled layers yields diffracted intensities with vanishing Bragg intensities at non-half-monolayer coverages and non-uniform background profiles. Our focus is on the determination of the diffuse background profile for two models of epitaxial growth at low temperatures where thermal diffusion is inoperative. Our calculations agree well with experimental LEED data for Pd/Pd(100) and Pt/Pd(100), though some unresolved questions remain. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & MATH,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RI Kang, Hway Chuan/A-3401-2012 NR 29 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD OCT PY 1991 VL 256 IS 1-2 BP 205 EP 215 DI 10.1016/0039-6028(91)91215-J PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GH679 UT WOS:A1991GH67900028 ER PT J AU BADDORF, AP WENDELKEN, JF AF BADDORF, AP WENDELKEN, JF TI HIGH COVERAGES OF OXYGEN ON CU(110) INVESTIGATED WITH XPS, LEED, AND HREELS SO SURFACE SCIENCE LA English DT Article ID ABSORPTION FINE-STRUCTURE; SURFACE RECONSTRUCTION; ROW RECONSTRUCTION; ION-SCATTERING; CUPROUS-OXIDE; CHEMISORPTION; ADSORPTION; COPPER; DIFFRACTION; SYSTEM AB Oxygen sites and coverages involved in the oxidation of Cu(110) have been investigated using HREELS, XPS, and LEED. High coverages of atomic oxygen were formed using low exposures of O2 by adsorbing at 15-20 K, irradiating with X-rays, and subsequently warming the crystal to 300 K. Coverages were determined from O1s areas in XPS. HREELS measurements disclose three surface sites and one subsurface site during the initial oxidation process. Long-bridge and tilted 3- or 4-coordinated sites are occupied before oxygen moves below the surface to form Cu2O. Oxide growth proceeds in islands. After the oxide appears, a third surface site is occupied when O atoms are insufficiently mobile to enter bulk sites. Only p(2 x 1) and c(6 x 2) long-range structures are observed with LEED. RP BADDORF, AP (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Baddorf, Arthur/I-1308-2016 OI Baddorf, Arthur/0000-0001-7023-2382 NR 29 TC 32 Z9 32 U1 1 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD OCT PY 1991 VL 256 IS 3 BP 264 EP 271 DI 10.1016/0039-6028(91)90869-T PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GK993 UT WOS:A1991GK99300006 ER PT J AU HALLEY, JW KOZLOWSKI, M MICHALEWICZ, M SMYRL, W TIT, N AF HALLEY, JW KOZLOWSKI, M MICHALEWICZ, M SMYRL, W TIT, N TI PHOTOELECTROCHEMICAL SPECTROSCOPY STUDIES OF TITANIUM-DIOXIDE SURFACES - THEORY AND EXPERIMENT SO SURFACE SCIENCE LA English DT Article ID OF-MOTION METHOD; ELECTRONIC-STRUCTURE; OXIDE-FILMS; TIO2; PHOTOELECTROLYSIS; METALS AB We describe experimental and theoretical studies of titanium dioxide. Photoelectrochemical data are presented for surfaces of known structure. The oxides were grown anodically on titanium metal. We report calculations of the electronic densities of states and optical conductivities of rutile TiO2 in finite-size samples disordered by the addition of oxygen vacancies for comparison with experiments. We conclude that in less disordered surfaces the electronic structure exhibited by the photospectra is very close to that of bulk rutile TiO2. In contrast. very thin oxides showed evidence of an electronic structure dominated by localized states near the band edge. More disordered oxides gave photospectra in which transitions associated with direct band gap transitions in bulk TiO2 seem to have been suppressed. Taking the structural information on the oxides into account, we argue that this suppression is probably a matrix element effect. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CSIRO,DIV INFORMAT TECHNOL,CARLETON,VIC,AUSTRALIA. UNIV MINNESOTA,CTR CORROS RES,DEPT CHEM ENGN & MAT SCI,MINNEAPOLIS,MN 55455. RP HALLEY, JW (reprint author), UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455, USA. NR 25 TC 34 Z9 35 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD OCT PY 1991 VL 256 IS 3 BP 397 EP 408 DI 10.1016/0039-6028(91)90882-S PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GK993 UT WOS:A1991GK99300019 ER PT J AU WINKER, S WOESE, CR AF WINKER, S WOESE, CR TI A DEFINITION OF THE DOMAINS ARCHAEA, BACTERIA AND EUCARYA IN TERMS OF SMALL SUBUNIT RIBOSOMAL-RNA CHARACTERISTICS SO SYSTEMATIC AND APPLIED MICROBIOLOGY LA English DT Article DE ARCHAEA; BACTERIA; EUCARYA; EURYARCHAEOTA; CRENARCHAEOTA; EVOLUTION; SIGNATURE; 16S; RIBOSOMAL-RNA ID ORDER STRUCTURAL ELEMENTS AB The number of small subunit rRNA sequences is now great enough that the three domains Archaea, Bacteria and Eucarya (Woese et al., 1990) can be reliably defined in terms of their sequence "signatures". Approximately 50 homologous positions (or nucleotide pairs) in the small subunit rRNA characterize and distinguish among the three. In addition, the three can be recognized by a variety of nonhomologous rRNA characters, either individual positions and/or higher-order structural features. The Crenarchaeota and the Euryarchaeota, the two archaeal kingdoms, can also be defined and distinguished by their characteristic compositions at approximately fifteen positions in the small subunit rRNA molecule. C1 UNIV ILLINOIS,DEPT MICROBIOL,131 BURRILL HALL,URBANA,IL 61801. ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. FU NINDS NIH HHS [NSG-7044] NR 9 TC 166 Z9 176 U1 11 U2 30 PU GUSTAV FISCHER VERLAG PI STUTTGART PA WOLLGRASWEG 49, D-70599 STUTTGART, GERMANY SN 0723-2020 J9 SYST APPL MICROBIOL JI Syst. Appl. Microbiol. PD OCT PY 1991 VL 14 IS 4 BP 305 EP 310 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA GP979 UT WOS:A1991GP97900001 PM 11540071 ER PT J AU MORRISON, JC BOTTCHER, C BOTTRELL, G AF MORRISON, JC BOTTCHER, C BOTTRELL, G TI SPLINE CALCULATIONS OF THE PHOTOIONIZATION OSCILLATOR-STRENGTHS OF H-3+ SO THEORETICA CHIMICA ACTA LA English DT Article DE NUMERICAL CALCULATION; OSCILLATOR STRENGTH; MOLECULAR ION ID BODY PERTURBATION-THEORY; NUMERICAL HARTREE-FOCK; DIATOMIC-MOLECULES; SCF CALCULATIONS; BASIS-SETS AB We apply spline methods to the problem of calculating continuum excitation probabilities of molecular systems under the influence of electromagnetic fields. Numerical results are given for the H-3+ molecular ion. C1 OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37831 USA. HARVARD SMITHSONIAN CTR ASTROPHYS, INST THEORET ATOM & MOLEC PHYS, CAMBRIDGE, MA 02138 USA. RP UNIV LOUISVILLE, DEPT PHYS, LOUISVILLE, KY 40292 USA. NR 36 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD OCT PY 1991 VL 80 IS 4-5 BP 245 EP 255 DI 10.1007/BF01117412 PG 11 WC Chemistry, Physical SC Chemistry GA GM733 UT WOS:A1991GM73300002 ER PT J AU BLUNDELL, SA HARTLEY, AC LIU, ZW MARTENSSONPENDRILL, AM SAPIRSTEIN, J AF BLUNDELL, SA HARTLEY, AC LIU, ZW MARTENSSONPENDRILL, AM SAPIRSTEIN, J TI CALCULATIONS OF THE PARITY NONCONSERVING 6S-]7S TRANSITION IN CESIUM SO THEORETICA CHIMICA ACTA LA English DT Article DE PARITY NONCONSERVATION; ELECTRONIC CORRELATION; COUPLED CLUSTER METHOD; RELATIVISTIC MANY-BODY EFFECTS; ELECTROWEAK RADIATIVE CORRECTIONS ID BODY PERTURBATION-THEORY; RELATIVISTIC PAIR EQUATION; COUPLED-CLUSTER APPROACH; WEAK NEUTRAL CURRENTS; NONCONSERVING OPTICAL-ROTATION; 6S1/2-7S1/2 CESIUM TRANSITION; VIOLATING ENERGY DIFFERENCE; HEAVY ATOMIC SYSTEMS; BASIS SET EXPANSION; FULL CCSDT MODEL AB The electroweak interaction between electrons and nucleons destroys the mirror symmetry of an atom. The size of the effect depends on the weak interaction constants as well as on the atomic structure. Small-scale experiments studying atomic parity non-conservation can thus give a quantitative test of the standard model for the electro-weak interaction - provided the atomic structure is sufficiently well understood. The increasing experimental accuracy, in particular for Cs, raises new demands on atomic theory. The various contributions to the parity non-conserving electric dipole transition matrix element are discussed together with the methods used to calculate them. The uncertainty in the atomic calculation is estimated. A discussion of radiative corrections with emphasis on the role of the top quark mass is also given. C1 UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22903. CHALMERS UNIV TECHNOL,DEPT PHYS,S-41296 GOTHENBURG,SWEDEN. UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556. UNIV OXFORD,CLARENDON LAB,OXFORD,ENGLAND. RP BLUNDELL, SA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 183 TC 22 Z9 22 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD OCT PY 1991 VL 80 IS 4-5 BP 257 EP 288 DI 10.1007/BF01117413 PG 32 WC Chemistry, Physical SC Chemistry GA GM733 UT WOS:A1991GM73300003 ER PT J AU MCLAUGHLIN, JF ROUGHGARDEN, J AF MCLAUGHLIN, JF ROUGHGARDEN, J TI PATTERN AND STABILITY IN PREDATOR PREY COMMUNITIES - HOW DIFFUSION IN SPATIALLY-VARIABLE ENVIRONMENTS AFFECTS THE LOTKA-VOLTERRA MODEL SO THEORETICAL POPULATION BIOLOGY LA English DT Article ID HETEROGENEOUS ENVIRONMENTS; WAVE SOLUTIONS; EQUATIONS C1 STANFORD UNIV,DEPT BIOL SCI,STANFORD,CA 94305. RP MCLAUGHLIN, JF (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 32 TC 28 Z9 28 U1 0 U2 5 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0040-5809 J9 THEOR POPUL BIOL JI Theor. Popul. Biol. PD OCT PY 1991 VL 40 IS 2 BP 148 EP 172 DI 10.1016/0040-5809(91)90051-G PG 25 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA GN482 UT WOS:A1991GN48200002 ER PT J AU SMITH, OL AF SMITH, OL TI COMPUTER-ASSISTED FLEXIBLE ROUTING OF MASS-TRANSIT BUS SYSTEMS SO TRANSPORTATION QUARTERLY LA English DT Article RP SMITH, OL (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 6 TC 1 Z9 1 U1 1 U2 1 PU ENO FOUNDATION TRANSPORT INC PI LANSDOWNE PA 44211 SLATE STONE CT, LANSDOWNE, VA 22075 SN 0278-9434 J9 TRANSPORT Q JI Transp. Q. PD OCT PY 1991 VL 45 IS 4 BP 581 EP 597 PG 17 WC Transportation SC Transportation GA GN117 UT WOS:A1991GN11700008 ER PT J AU YUST, CS DEVORE, CE AF YUST, CS DEVORE, CE TI THE FRICTION AND WEAR OF LUBRICATED SI3N4/SIC(W) COMPOSITES SO TRIBOLOGY TRANSACTIONS LA English DT Article ID MAPS AB The friction and wear of a 20 v/o silicon carbide whisker-silicon nitride matrix composite was measured at room temperature in both lubricated and unlubricated sliding. A pin-on-disk test configuration was used in which the pin member was a 9.53 mm diameter sphere. Silicon carbide and silicon nitride spheres were tested against the composite in both unidirectional and reciprocating sliding. The range of experimental parameters included normal forces from 1 to 45 N, velocities of 0.1 and 0.3 m/s and test durations of five minutes to three hours. The lubricant used in the room temperature tests was a commercial synthetic, fully formulated engine oil (5W30). In unlubricated sliding, silicon nitride produced more severe wear of the composite than did silicon carbide. In lubricated sliding, very little wear occurs in either sliding pair at even the longest test exposure. The data are presented in "wear space" co-ordinates and this form of presentation is compared to other wear mechanism map concepts presently in use. RP YUST, CS (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 10 TC 9 Z9 9 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD OCT PY 1991 VL 34 IS 4 BP 497 EP 504 DI 10.1080/10402009108982062 PG 8 WC Engineering, Mechanical SC Engineering GA GK781 UT WOS:A1991GK78100003 ER PT J AU CARLSON, CL ADRIANO, DC SAJWAN, KS ABELS, SL THOMA, DP DRIVER, JT AF CARLSON, CL ADRIANO, DC SAJWAN, KS ABELS, SL THOMA, DP DRIVER, JT TI EFFECTS OF SELECTED TRACE-METALS ON GERMINATING-SEEDS OF 6 PLANT-SPECIES SO WATER AIR AND SOIL POLLUTION LA English DT Article ID METABOLISM; ELONGATION; TOXICITY AB Seeds of cabbage, lettuce, millet, radish, turnip, and wheat were treated with solutions containing Be, Ni, Tl, or V, and subsequent effects on seed germination and radicle elongation were measured after three days. Treatment with low concentrations of Be, Ni, or V stimulated root elongation in most species. Higher concentrations of these elements and all treatment with Tl caused reductions in root elongation. In general, turnip and lettuce were the most sensitive of the plants studied to the metals tested, while wheat and millet were the least sensitive. C1 SAVANNAH RIVER ECOL LAB,DIV BIOGEOCHEM,AIKEN,SC 29808. NR 23 TC 33 Z9 34 U1 0 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 1991 VL 59 IS 3-4 BP 231 EP 240 DI 10.1007/BF00211832 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA GP466 UT WOS:A1991GP46600003 ER PT J AU WILDE, EW AF WILDE, EW TI COMPARISON OF 3 METHODS FOR MEASURING RESIDUAL CHLORINE SO WATER RESEARCH LA English DT Note DE RESIDUAL CHLORINE; AMPEROMETRIC TITRATION; DPD METHOD; ION-SPECIFIC ELECTRODE AB Three EPA-approved residual chlorine detection methods were compared using standard solutions and water collected from the Savannah River which is used to cool reactors at the Savannah River Site (SRS) near Aiken, S.C. The testing was part of an experimental program to develop baseline data for the design of a proposed cooling tower for the K-reactor at the SRS. A series of total residual chlorine (TRC) measurements made simultaneously by three methods revealed that for the river water samples, the DPD method (Hach DR-100 kit) and the amperometric titration method produced statistically similar results while an ion-selective electrode method, standardized according to the manufacturer's instructions, provided significantly lower values. The DPD method (utilizing a Hach DR-100 kit) was the recommended method for future monitoring of the water evaluated because this method is simple, provides quick results, measures both total residual chlorine (TRC) and free residual chlorine (FRC) and is equally suitable for measurements in the field and laboratory. RP WILDE, EW (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER SITE,AIKEN,SC 29808, USA. NR 6 TC 5 Z9 5 U1 5 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0043-1354 J9 WATER RES JI Water Res. PD OCT PY 1991 VL 25 IS 10 BP 1303 EP 1305 DI 10.1016/0043-1354(91)90071-W PG 3 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA GF306 UT WOS:A1991GF30600018 ER PT J AU ROSE, KA COOK, RB BRENKERT, AL GARDNER, RH HETTELINGH, JP AF ROSE, KA COOK, RB BRENKERT, AL GARDNER, RH HETTELINGH, JP TI SYSTEMATIC COMPARISON OF ILWAS, MAGIC, AND ETD WATERSHED ACIDIFICATION MODELS .1. MAPPING AMONG MODEL INPUTS AND DETERMINISTIC RESULTS SO WATER RESOURCES RESEARCH LA English DT Article ID ACID DEPOSITION; RESPONSES AB The effects of investigator-dependent configuration and calibration procedures on model predictions are difficult to evaluate when sufficient data for model testing are not available. We derived a set of rules and algorithms (referred to as input mapping) to provide consistent inputs for the Integrated Lake Watershed Acidification Study (ILWAS), Model of Acidification of Groundwater in Catchments (MAGIC), and Enhanced Trickle Down (ETD) watershed acidification models without calibration. Model predictions of lake chemistry based on input mapping were similar for two dissimilar northeast U.S. watersheds, and were within the variability obtained with independent calibration of the three models and the interannual variability observed in two studies of natural watersheds. In a companion paper (Rose et al., this issue), Monte Carlo analysis is used, in conjunction with input mapping, to compare model predictions under varying inputs. C1 NATL INST PUBL HLTH & ENVIRONM PROTECT,3720 BA BILTHOVEN,NETHERLANDS. RP ROSE, KA (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. OI Cook, Robert/0000-0001-7393-7302 NR 24 TC 22 Z9 22 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD OCT PY 1991 VL 27 IS 10 BP 2577 EP 2589 DI 10.1029/91WR01718 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA GJ136 UT WOS:A1991GJ13600009 ER PT J AU ROSE, KA BRENKERT, AL COOK, RB GARDNER, RH HETTELINGH, JP AF ROSE, KA BRENKERT, AL COOK, RB GARDNER, RH HETTELINGH, JP TI SYSTEMATIC COMPARISON OF ILWAS, MAGIC, AND ETD WATERSHED ACIDIFICATION MODELS .2. MONTE-CARLO ANALYSIS UNDER REGIONAL VARIABILITY SO WATER RESOURCES RESEARCH LA English DT Article ID ACID DEPOSITION; RESPONSES AB A combination of input mapping (Rose et al., this issue) and Monte Carlo simulation was used to quantitatively compare the predictions of the Integrated Lake Watershed Acidification Study (ILWAS), Model of Acidification of Groundwater in Catchments (MAGIC), and Enhanced Trickle Down (ETD) watershed acidification models. Monte Carlo simulation was used to impose regional variability on selected model inputs of two dissimilar watersheds resembling those found in the northeastern United States for four different SO42- deposition scenarios. Model predictions were viewed in aggregate (distributions, medians) corresponding to population-level predictions, and on an iteration-by-iteration basis corresponding to watershed-specific predictions. For each of these, predicted values of acid-neutralizing capacity (ANC) were treated as relative scale (changes in ANC in response to changes in deposition) and absolute scale (ANC concentrations, number of acidic lakes) predictions. Aggregate and iteration-specific predictions viewed on a relative scale were similar for three models under small to moderate changes in SO42- deposition. Aggregate and iteration-specific predictions differed among models when viewed on an absolute scale. Absolute scale predictions were most similar under conditions of high variability in deposition. Proper interpretation of multiple model forecasts requires objective quantification of the effects of model differences on predictions. C1 NATL INST PUBL HLTH & ENVIRONM PROTECT,3720 BA BILTHOVEN,NETHERLANDS. RP ROSE, KA (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. OI Cook, Robert/0000-0001-7393-7302 NR 17 TC 17 Z9 18 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD OCT PY 1991 VL 27 IS 10 BP 2591 EP 2603 DI 10.1029/91WR01717 PG 13 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA GJ136 UT WOS:A1991GJ13600010 ER PT J AU NIELSEN, JM PINDER, GF KULP, TJ ANGEL, SM AF NIELSEN, JM PINDER, GF KULP, TJ ANGEL, SM TI INVESTIGATION OF DISPERSION IN POROUS-MEDIA USING FIBEROPTIC TECHNOLOGY SO WATER RESOURCES RESEARCH LA English DT Article AB This paper presents the results of a laboratory investigation of the characteristics of solute transport utilizing fiber-optic technology. In this work, we examine solute transport in a uniform homogeneous porous medium with a one-dimensional flow system using a fiber-optic fluorimeter system. In a series of experiments, fiber-optic sensors are used in situ in a packed column to make observations of solute concentration at the microscopic level. The tracer that is employed is assumed to be ideal and the flow field is restricted to be fully saturated and laminar. Using data measured at the pore level, we study the spatial variability in the concentration field during miscible displacement and relate these observations to the macroscopic flow characteristics. C1 UNIV VERMONT,COLL ENGN & MATH,BURLINGTON,VT 05405. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP NIELSEN, JM (reprint author), ENVIRON CORP,210 CARNEGIE CTR,SUITE 210,PRINCETON,NJ 08540, USA. OI Angel, Stanley/0000-0002-0328-0568 NR 12 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD OCT PY 1991 VL 27 IS 10 BP 2743 EP 2749 DI 10.1029/91WR01719 PG 7 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA GJ136 UT WOS:A1991GJ13600022 ER PT J AU LEVINE, HS HIGGINS, KL AF LEVINE, HS HIGGINS, KL TI DETERMINATION OF PHOSPHORUS IN BOROPHOSPHOSILICATE OR PHOSPHOSILICATE GLASS-FILMS ON A SILICON-WAFER BY WAVELENGTH-DISPERSIVE X-RAY SPECTROMETRY SO X-RAY SPECTROMETRY LA English DT Article AB A wavelength-dispersive x-ray fluorescence method was developed for the determination of phosphorus in borophosphosilicate glass (BPSG) or phosphosilicate glass (PSG) films on a silicon wafer. Secondary spectral line intensities from the coated wafer are compared with those of an uncoated Si wafer and a fused P standard. The results are then converted to phosphorus content and surface density of the film by equations for the relative spectral line intensities of P and Si with corrections for the shift in the Si peak due to chemical bonding. Results obtained on an annealed set of PSG samples using four different incident spectra were self-consistent and correlated well with independent inductively coupled plasma atomic emission spectrometric analyses for phosphorus and ellipsometric measurements of thickness. Preliminary results with BPSG samples were promising and showed that results for phosphorus were not sensitive to boron concentrations in the films. RP LEVINE, HS (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 4 TC 2 Z9 2 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD OCT PY 1991 VL 20 IS 5 BP 255 EP 261 DI 10.1002/xrs.1300200507 PG 7 WC Spectroscopy SC Spectroscopy GA GL184 UT WOS:A1991GL18400005 ER PT J AU RINCHIK, EM JOHNSON, DK MARGOLIS, FL JACKSON, IJ RUSSELL, LB CARPENTER, DA AF RINCHIK, EM JOHNSON, DK MARGOLIS, FL JACKSON, IJ RUSSELL, LB CARPENTER, DA TI REVERSE GENETICS IN THE MOUSE AND ITS APPLICATION TO THE STUDY OF DEAFNESS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID OLFACTORY MARKER PROTEIN; ALBINO-DELETION COMPLEX; SEX-DETERMINING REGION; CYSTIC-FIBROSIS GENE; MOLECULAR-CLONING; LOCUS REGION; DNA SEGMENT; CDNA; CHROMOSOME; IDENTIFICATION C1 WISTAR INST,PHILADELPHIA,PA 19104. ROCHE INST MOLEC BIOL,CHEMOSENSORY NEUROBIOL LAB,NUTLEY,NJ 07110. WESTERN GEN HOSP,MRC,HUMAN GENET UNIT,EDINBURGH EH4 2XU,MIDLOTHIAN,SCOTLAND. RP RINCHIK, EM (reprint author), OAK RIDGE NATL LAB,DIV BIOL,POB 2009,OAK RIDGE,TN 37831, USA. FU NHGRI NIH HHS [HG 00370] NR 40 TC 12 Z9 12 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD SEP 30 PY 1991 VL 630 BP 80 EP 92 DI 10.1111/j.1749-6632.1991.tb19577.x PG 13 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA JM204 UT WOS:A1991JM20400009 PM 1952626 ER PT J AU WARREN, WL KANICKI, J ROBERTSON, J LENAHAN, PM AF WARREN, WL KANICKI, J ROBERTSON, J LENAHAN, PM TI ENERGY-LEVEL OF THE NITROGEN DANGLING BOND IN AMORPHOUS-SILICON NITRIDE SO APPLIED PHYSICS LETTERS LA English DT Article ID DOMINANT DEEP TRAP; FILMS; CENTERS; CHARGE; STATES AB The composition dependence and room-temperature metastability of the paramagnetic nitrogen dangling-bond center is amorphous silicon nitride suggest that its energy level lies close to the N p-pi states, in agreement with theoretical calculations. C1 NATL POWER LABS,LEATHERHEAD KT22 7SE,SURREY,ENGLAND. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. PENN STATE UNIV,UNIVERSITY PK,PA 16802. RP WARREN, WL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI Kanicki, Jerzy/E-2753-2016 OI Kanicki, Jerzy/0000-0002-3649-8360 NR 19 TC 38 Z9 38 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 30 PY 1991 VL 59 IS 14 BP 1699 EP 1701 DI 10.1063/1.106222 PG 3 WC Physics, Applied SC Physics GA GH409 UT WOS:A1991GH40900016 ER PT J AU CAMPBELL, IH WATKINS, DE SMITH, DL SUBBANNA, S KROEMER, H AF CAMPBELL, IH WATKINS, DE SMITH, DL SUBBANNA, S KROEMER, H TI ELECTROOPTIC MODULATION IN POLAR GROWTH AXIS INGAAS/GAAS MULTIPLE QUANTUM-WELLS SO APPLIED PHYSICS LETTERS LA English DT Article ID STRAINED-LAYER SUPERLATTICES; OPTICAL-PROPERTIES AB We present electrooptic modulation results on [100], [211]A and [211]B oriented InGaAs/GaAs multiple quantum wells. Internal electric fields are generated by a combination of strain, due to lattice mismatch, and the piezoelectric properties of III-V semiconductors in the [211] structures. These fields have opposite orientation in the [211]A and [211]B samples. They do not occur in the [100] samples. The total electric field is a superposition of the strain-generated field, the built-in field from the p-n junction and any externally applied field. We show that whereas in the conventional [100] structures the exciton energy is a quadratic function of applied field, the strain-generated fields cause a linear shift in the exciton resonance with applied field in the [211] structures. In addition, the direction of the excitonic shift is opposite in the [211]A and [211]B samples, because the sign of the strain-generated fields are opposite for these samples. C1 UNIV CALIF SANTA BARBARA,ECE,SANTA BARBARA,CA 93106. RP CAMPBELL, IH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Schaff, William/B-5839-2009 NR 11 TC 16 Z9 16 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 30 PY 1991 VL 59 IS 14 BP 1711 EP 1713 DI 10.1063/1.106226 PG 3 WC Physics, Applied SC Physics GA GH409 UT WOS:A1991GH40900020 ER PT J AU ESTREICHER, SK SEAGER, CH ANDERSON, RA AF ESTREICHER, SK SEAGER, CH ANDERSON, RA TI BISTABILITY OF DONOR-HYDROGEN COMPLEXES IN SILICON - A MECHANISM FOR DEBONDING SO APPLIED PHYSICS LETTERS LA English DT Article ID CRYSTALLINE SILICON; INTERSTITIAL HYDROGEN; MICROSCOPIC STRUCTURE; CLUSTER CALCULATIONS; ENERGY PROFILES; PASSIVATION; PHOSPHORUS; SEMICONDUCTORS; MUONIUM; DIAMOND AB The {D,H}+ complex in silicon, with D = P or As, is studied near the ab initio Hartree-Fock level. The results show that the transitions between {D,H}0 and {D,H}+ involve a drastic change in the equilibrium geometry and electronic structure of the complex. The implications of these results on the observed dependence of the debonding rates on majority- and minority-carrier concentrations for both As and P donors are discussed. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP ESTREICHER, SK (reprint author), TEXAS TECH UNIV,DEPT PHYS,LUBBOCK,TX 79409, USA. NR 23 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 30 PY 1991 VL 59 IS 14 BP 1773 EP 1775 DI 10.1063/1.106196 PG 3 WC Physics, Applied SC Physics GA GH409 UT WOS:A1991GH40900041 ER PT J AU VAITKUS, MR EDDLEMAN, LE AF VAITKUS, MR EDDLEMAN, LE TI TREE SIZE AND UNDERSTORY PHYTOMASS PRODUCTION IN A WESTERN JUNIPER WOODLAND SO GREAT BASIN NATURALIST LA English DT Article DE JUNIPERUS-OCCIDENTALIS; WESTERN JUNIPER; PHYTOMASS PRODUCTION; UNDERSTORY; TREE SIZE AB Understory phytomass production in a western juniper (Juniperus occidentalis) woodland was examined relative to tree size in central Oregon in 1983 and 1984. Vegetation was sampled in two zones, the canopy zone (beneath the canopy) and the intercanopy zone (the space between canopies), on two adjacent sites-a lower slope site with shallow soil and an upper slope site with deeper soil. Sampling was stratified into three tree size classes. Individual species production was significantly affected by tree size and location relative to tree canopy. Production of bottlebrush squirreltail, bluebunch wheatgrass, cheatgrass, miscellaneous annual grasses, perennial forbs, and annual forbs increased with increasing tree size. Sandberg bluegrass production was greater in the intercanopy than the canopy zone, while production of bottlebrush squirreltail, bluebunch wheatgrass, miscellaneous annual grasses, and both perennial and annual forbs was greater in the canopy zone. Production of cheatgrass was determined by the interaction of tree size and zone. Phytomass relationships were expressed to a greater degree on the upper slope site, where total production exceeded that of the lower slope site by approximately 50% the second year of the study. Individual trees appear to exert a great influence on associated vegetation as western juniper woodlands progress from the seedling (tree establishment) phase to closed stands of mature trees. Original community dominants appear to be spatially segregated beneath tree canopies and associated with large trees, while formerly less common species, such as cheatgrass, come to dominate the entire site. RP VAITKUS, MR (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. NR 0 TC 13 Z9 13 U1 0 U2 1 PU BRIGHAM YOUNG UNIV PI PROVO PA 290 LIFE SCIENCE MUSEUM, PROVO, UT 84602 SN 0017-3614 J9 GREAT BASIN NAT JI Gt. Basin Nat. PD SEP 30 PY 1991 VL 51 IS 3 BP 236 EP 243 PG 8 WC Ecology SC Environmental Sciences & Ecology GA GK877 UT WOS:A1991GK87700003 ER PT J AU SHUKLA, P COTTS, PM MILLER, RD RUSSELL, TP SMITH, BA WALLRAFF, GM BAIER, M THIYAGARAJAN, P AF SHUKLA, P COTTS, PM MILLER, RD RUSSELL, TP SMITH, BA WALLRAFF, GM BAIER, M THIYAGARAJAN, P TI CONFORMATIONAL TRANSITION STUDIES OF ORGANOSILANE POLYMERS BY LIGHT AND NEUTRON-SCATTERING SO MACROMOLECULES LA English DT Article ID ISOMERIC STATE CALCULATIONS; DYNAMIC STRUCTURE FACTOR; TO-COIL TRANSITION; CHAIN STIFFNESS; LINEAR-CHAINS; POLY(DIACETYLENES); POLYDIACETYLENES AB The solution properties of several sigma-conjugated alkyl-substituted organosilane polymers have been investigated in dilute solution using light and neutron scattering. The particle scattering functions are consistent with those calculated for a wormlike chain with a persistence length, l(pers), of approximately 6-7 nm. Measurements have also been done at low temperatures where thermochromic transitions are observed in the electronic absorption spectra. Interpretation of the particle scattering functions at temperatures at or below the transition regions is complicated by the presence of aggregates in the solutions. The results are similar to those observed for pi-conjugated polymers such as the polydiacetylenes in solution. C1 IBM CORP,DIV RES,ALMADEN RES CTR,SAN JOSE,CA 95120. ARGONNE NATL LAB,IPNS,ARGONNE,IL 60439. NR 40 TC 45 Z9 46 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 30 PY 1991 VL 24 IS 20 BP 5606 EP 5613 DI 10.1021/ma00020a020 PG 8 WC Polymer Science SC Polymer Science GA GH467 UT WOS:A1991GH46700020 ER PT J AU RUSSELL, TP MENELLE, A HAMILTON, WA SMITH, GS SATIJA, SK MAJKRZAK, CF AF RUSSELL, TP MENELLE, A HAMILTON, WA SMITH, GS SATIJA, SK MAJKRZAK, CF TI WIDTH OF HOMOPOLYMER INTERFACES IN THE PRESENCE OF SYMMETRICAL DIBLOCK COPOLYMERS SO MACROMOLECULES LA English DT Article ID BLOCK COPOLYMERS; NEUTRON REFLECTIVITY; BLENDS; MIXTURES; TENSION; SYSTEMS; FILMS AB The interface between polystyrene and poly(methyl methacrylate) homopolymers was investigated as a function of the concentration of added symmetric diblock copolymer of PS and PMMA, denoted P(S-b-MMA), using neutron reflectivity. It was found that as the number of P(S-b-MMA) chains added to the interface between PS and PMMA was increased, the width of the gradient between the PS and PMMA segments broadened. In particular, the width of the interface between PS and PMMA homopolymers is 50 angstrom and, with the addition of P(S-b-MMA), increases to approximately 85 angstrom. At an amount corresponding to approximately half the thickness of the lamellar microdomain periodicity in the bulk, the interface becomes saturated with the copolymer. Further addition of copolymer chains to the interface results in a marked increase in the off-specular scattering, which is associated with either an ordering of the copolymer chains at the interface or an increase in the curvature of the interface. Studies were also performed on mixtures of homopolymers and copolymers. Here, the interface between the lamellar microdomains of the P(S-b-MMA) is found to increase from 50 angstrom for the pure copolymer to 75 angstrom as PS and PMMA homopolymer is added to the copolymer. The broadening of the interface seen in both sets of experiments is due to a significant penetration of the homopolymer into the interfacial region. These results are consistent with the reduction in the interfacial tension between the homopolymers with the addition of the diblock copolymer. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NATL INST STAND & TECHNOL,DIV REACTOR RADIAT,GAITHERSBURG,MD 20899. RP RUSSELL, TP (reprint author), IBM CORP,DIV RES,ALMADEN RES CTR,650 HARRY RD,SAN JOSE,CA 95120, USA. NR 35 TC 77 Z9 77 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 30 PY 1991 VL 24 IS 20 BP 5721 EP 5726 DI 10.1021/ma00020a036 PG 6 WC Polymer Science SC Polymer Science GA GH467 UT WOS:A1991GH46700036 ER PT J AU COOPER, A SUSSKIND, L THORLACIUS, L AF COOPER, A SUSSKIND, L THORLACIUS, L TI 2-DIMENSIONAL QUANTUM COSMOLOGY SO NUCLEAR PHYSICS B LA English DT Article ID STRING THEORY; BACKGROUND FIELDS; CRITICAL-BEHAVIOR; 3RD QUANTIZATION; GRAVITY; CONSTANT; COHERENCE; INCOHERENCE; EQUATIONS; TOPOLOGY AB Two-dimensional quantum gravity coupled to conformally invariant matter with central charge c > 25 has been proposed as a toy model for quantum gravity in higher dimensions. The associated "Wheeler-DeWitt equation" is non-linear and unstable to forming a condensate of baby universes. This will occur even in the classical c --> infinity limit. Small fluctuations about this background describe the propagation of single universes and satisfy a more conventional linear Wheeler-DeWitt equation. The resulting two-dimensional cosmology depends on details of the non-linear dynamics. In particular the existence of a large-scale cosmological constant is determined by the behavior of a string theoretic tachyon potential near its minimum. C1 STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. RP COOPER, A (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. RI Thorlacius, Larus/L-7487-2015 NR 58 TC 42 Z9 42 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD SEP 30 PY 1991 VL 363 IS 1 BP 132 EP 162 DI 10.1016/0550-3213(91)90238-S PG 31 WC Physics, Particles & Fields SC Physics GA GD634 UT WOS:A1991GD63400008 ER PT J AU RAY, RM BRASHEAR, JP BIGLARBIGI, K AF RAY, RM BRASHEAR, JP BIGLARBIGI, K TI CLASSIFICATION-SYSTEM TARGETS UNRECOVERED UNITED-STATES OIL-RESERVES SO OIL & GAS JOURNAL LA English DT Article RP RAY, RM (reprint author), US DOE,BARTLESVILLE PROJECT OFF,BARTLESVILLE,OK, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO ENERGY GROUP PI TULSA PA 1421 S SHERIDAN RD PO BOX 1260, TULSA, OK 74101 SN 0030-1388 J9 OIL GAS J JI Oil Gas J. PD SEP 30 PY 1991 VL 89 IS 39 BP 89 EP 93 PG 5 WC Energy & Fuels; Engineering, Petroleum SC Energy & Fuels; Engineering GA GH536 UT WOS:A1991GH53600013 ER PT J AU CVETIC, M QUEVEDO, F REY, SJ AF CVETIC, M QUEVEDO, F REY, SJ TI STRINGY DOMAIN-WALLS AND TARGET-SPACE MODULAR INVARIANCE SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERSTRING MODELS; SUPERSYMMETRY BREAKING; GAUGINO CONDENSATION; FIELD-THEORIES; FALSE VACUUM; WORLD SHEET; DUALITY; AXION; PHYSICS; FATE AB Based on the target-space modular invariance of the nonpertubative superpotential of the four-dimensional N = 1 supersymmetric string vacua, we find topologically stable, stringy domain walls of nontrivial compactification modulus field configurations. They are supersymmetric solutions, thus saturating the Bogomolnyi bound. Their physical implications are discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORY,LOS ALAMOS,NM 87545. UNIV FLORIDA,INST FUNDAMENTAL THEORY,GAINESVILLE,FL 32611. RP CVETIC, M (reprint author), UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104, USA. NR 44 TC 79 Z9 79 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 30 PY 1991 VL 67 IS 14 BP 1836 EP 1839 DI 10.1103/PhysRevLett.67.1836 PG 4 WC Physics, Multidisciplinary SC Physics GA GH407 UT WOS:A1991GH40700007 ER PT J AU TRUGENBERGER, CA MENIKOFF, R SHARP, DH AF TRUGENBERGER, CA MENIKOFF, R SHARP, DH TI SELF-INDUCED AHARONOV-BOHM PHASE OF ANYONIC MATTER SO PHYSICAL REVIEW LETTERS LA English DT Article ID STATISTICS; TRANSMUTATIONS; PARTICLES; SPIN AB We identify a new global topological self-interaction of anyons represented by a self-induced Aharonov-Bohm phase measuring the oriented self-intersection number of a closed particle trajectory in the plane. RP TRUGENBERGER, CA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 21 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 30 PY 1991 VL 67 IS 14 BP 1922 EP 1925 DI 10.1103/PhysRevLett.67.1922 PG 4 WC Physics, Multidisciplinary SC Physics GA GH407 UT WOS:A1991GH40700029 ER PT J AU KEIMER, B BIRGENEAU, RJ CASSANHO, A ENDOH, Y ERWIN, RW KASTNER, MA SHIRANE, G AF KEIMER, B BIRGENEAU, RJ CASSANHO, A ENDOH, Y ERWIN, RW KASTNER, MA SHIRANE, G TI SCALING BEHAVIOR OF THE GENERALIZED SUSCEPTIBILITY IN LA2-XSRXCUO4+Y SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTIVITY; OXIDES AB We have measured the static and dynamic spin fluctuations in a crystal of La2-xSrxCuO4+y in the spin-glass doping regime. The static spin correlations are well described by a simple model in which the inverse correlation length kappa(x, T) = kappa(x, 0) + kappa(0, T). The dynamic spin fluctuations exhibit a simple scaling behavior in omega/T for temperatures 10 K less-than-or-equal-to T less-than-or-equal-to 500 K for the measured energies 4.5 less-than-or-equal-to omega less-than-or-equal-to 12 meV. C1 TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 980,JAPAN. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP KEIMER, B (reprint author), MIT,CTR MAT SCI & ENGN,CAMBRIDGE,MA 02139, USA. NR 19 TC 136 Z9 137 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 30 PY 1991 VL 67 IS 14 BP 1930 EP 1933 DI 10.1103/PhysRevLett.67.1930 PG 4 WC Physics, Multidisciplinary SC Physics GA GH407 UT WOS:A1991GH40700031 ER PT J AU PETTIT, DR BRAND, HR AF PETTIT, DR BRAND, HR TI ON THE INFLUENCE OF NEAR ZERO GRAVITY ON THE ROSENSWEIG INSTABILITY IN MAGNETIC FLUIDS SO PHYSICS LETTERS A LA English DT Article ID CYLINDRICAL CONTAINER; THRESHOLD AB We investigate how an enhanced (1.8g) and reduced (10(-2)g) gravitational force influences the instability threshold and the pattern formed for the Rosensweig instability in ferrofluids. From the results of our parabolic flights it emerges that we can confirm quantitatively the predictions from the ferrohydrodynamic equations for the scaling with gravity of the critical values of the wavelength and the magnetic field for enhanced gravity. For reduced gravity we observe above threshold qualitatively new patterns that have not been predicted and we give a qualitative explanation. C1 UNIV ESSEN GESAMTHSCH, FACHBEREICH PHYS 7, W-4300 ESSEN 1, GERMANY. UNIV CALIF LOS ALAMOS SCI LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. RP PETTIT, DR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, POB 1663, LOS ALAMOS, NM 87545 USA. NR 14 TC 2 Z9 2 U1 2 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD SEP 30 PY 1991 VL 159 IS 1-2 BP 55 EP 60 DI 10.1016/0375-9601(91)90161-Z PG 6 WC Physics, Multidisciplinary SC Physics GA GK417 UT WOS:A1991GK41700010 ER PT J AU BLAU, PJ DEVORE, CE AF BLAU, PJ DEVORE, CE TI MACHINING AND WEAR RELATIONSHIPS IN AN ORDERED INTERMETALLIC ALLOY SO WEAR LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON WEAR OF MATERIALS CY APR 07-11, 1991 CL ORLANDO, FL ID BEHAVIOR; NICKEL AB There are many commonalities between machining (metal cutting) and sliding friction and wear. Machining (lathe-turning) experiments and ball-on-disk wear experiments have been conducted on a nickel aluminide alloy (IC-218 LZr). The wear tests were performed at room temperature and 923 K (650-degrees-C) using tungsten carbide as the slider material to simulate the cutting tool material. The effects of cutting speed, use of a coolant and type of cutting tool on surface finish, depth of workpiece subsurface damage and cutting chip characteristics are reported. The depth of damage in sliding we ar experiments is compared to that for lathe-turning experiments in an attempt to estimate the shear forces on the cut surface. Friction coefficients and wear factors for tungsten carbide sliding on IC-218 LZr depended on the magnitude of the normal force and on the sliding temperature. The wear rate of the nickel aluminide alloy decreased as the temperature increased. The relationships between the observed friction and wear behavior of nickel aluminide and its machining characteristics are discussed. RP BLAU, PJ (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 9 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD SEP 30 PY 1991 VL 149 IS 1-2 BP 27 EP 40 DI 10.1016/0043-1648(91)90362-X PG 14 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA GL443 UT WOS:A1991GL44300003 ER PT J AU AJAYI, OO ERDEMIR, A ERCK, RA FENSKE, GR NICHOLS, FA AF AJAYI, OO ERDEMIR, A ERCK, RA FENSKE, GR NICHOLS, FA TI THE ROLE OF SOFT (METALLIC) FILMS IN THE TRIBOLOGICAL BEHAVIOR OF CERAMIC MATERIALS SO WEAR LA English DT Article ID ION-ASSISTED DEPOSITION; SLIDING FRICTION; SILVER FILMS; WEAR; COATINGS; LUBRICATION AB The friction coefficient and wear rate in structural ceramic materials are often too high to make them attractive for applications requiring dry sliding. The role of a thin soft silver film in improving the tribological characteristics of silicon nitride materials is investigated in this study. In a pin-on-disc contact configuration in reciprocating motion, the friction coefficient was reduced by about 50% and the wear rate by one to two orders of magnitude. The friction reduction is thought to be due to the reduction in the contact interface shear strength caused by the presence of the soft film. The wear rate reduction is probably due to modification of the contact stresses by the film. Combined, these two factors lead to a decrease in the magnitude of the damaging tensile stresses. The durability and thus the effectiveness of the film is very dependent on the bond strength (i.e. adhesion strength) between the film and the substrate. RP AJAYI, OO (reprint author), ARGONNE NATL LAB, DIV MAT & COMPONENTS TECHNOL, ARGONNE, IL 60439 USA. NR 22 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 EI 1873-2577 J9 WEAR JI Wear PD SEP 30 PY 1991 VL 149 IS 1-2 BP 221 EP 232 DI 10.1016/0043-1648(91)90375-5 PG 12 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA GL443 UT WOS:A1991GL44300016 ER PT J AU LIN, S VANAMERONGEN, H STRUVE, WS AF LIN, S VANAMERONGEN, H STRUVE, WS TI ULTRAFAST PUMP-PROBE SPECTROSCOPY OF BACTERIOCHLOROPHYLL-C ANTENNAE IN BACTERIOCHLOROPHYLL-A-CONTAINING CHLOROSOMES FROM THE GREEN PHOTOSYNTHETIC BACTERIUM CHLOROFLEXUS-AURANTIACUS SO BIOCHIMICA ET BIOPHYSICA ACTA LA English DT Article DE ANTENNA; BACTERIAL PHOTOSYNTHESIS; BACTERIOCHLOROPHYLL; CHLOROSOME; PUMP-PROBE SPECTROSCOPY; ULTRAFAST SPECTROSCOPY; (C-AURANTIACUS) ID ENERGY-TRANSFER KINETICS; PIGMENT ORGANIZATION; PICOSECOND; CHLOROBIUM; DIMERS; CELLS AB Time-dependent isotropic and anisotropic absorption difference profiles have been obtained with 2 ps resolution for the (BChl) bacteriochlorophyll c antenna in BChl a-containing chlorosomes from the green photosynthetic bacterium Chloroflexus aurantiacus. The isotropic absorption difference spectra are bipolar; they are dominated by excited state absorption at wavelengths < 725 nm, and by ground state photobleaching at wavelengths > 735 nm. The entire isotropic spectrum exhibits a dynamic blue shift over approx. 4 nm with a time constant of approx. 7 ps. All of these phenomena are rationalized in terms of a linear exciton model that resembles the theory of J-aggregates. In this theory, the occurrence of the dynamic blue shift corresponds to relaxation between Q(y) excitation components; it cannot readily be explained using a model that assumes that the excitations are localized on single chromophores within 1 ps. The anisotropic decay times, resolved here for the first time with our 2 ps fwhm instrument function, are approx. 7 +/- 1 ps at 720 nm and 4 +/- 1 ps at 740 nm. The residual anisotropy r(infinity) is 0.32 +/- 0.02 at 740 nm, which is in good agreement with fluorescence and linear dichroism measurements. These anisotropy functions initialize to 0.4 within error, indicating that subpicosecond depolarization is not prevalent. C1 US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RI van Amerongen, Herbert/J-9483-2016 OI van Amerongen, Herbert/0000-0002-9783-2895 NR 33 TC 43 Z9 45 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-3002 J9 BIOCHIM BIOPHYS ACTA PD SEP 27 PY 1991 VL 1060 IS 1 BP 13 EP 24 DI 10.1016/S0005-2728(05)80113-6 PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GL317 UT WOS:A1991GL31700002 ER PT J AU WILLIAMS, DJ MCENTIRE, RW KRIMIGIS, SM ROELOF, EC JASKULEK, S TOSSMAN, B WILKEN, B STUDEMANN, W ARMSTRONG, TP FRITZ, TA LANZEROTTI, LJ ROEDERER, JG AF WILLIAMS, DJ MCENTIRE, RW KRIMIGIS, SM ROELOF, EC JASKULEK, S TOSSMAN, B WILKEN, B STUDEMANN, W ARMSTRONG, TP FRITZ, TA LANZEROTTI, LJ ROEDERER, JG TI ENERGETIC PARTICLES AT VENUS - GALILEO RESULTS SO SCIENCE LA English DT Article ID BOW SHOCK; ACCELERATION; UPSTREAM AB At Venus the Energetic Particles Detector (EPD) on the Galileo spacecraft measured the differential energy spectra and angular distributions of ions greater-than-or-similar-to 22 kiloelectron volts (keV) and electrons greater-than-or-similar-to 15 keV in energy. The only time particles were observed by EPD was in a series of episodic events [approximately 0546 to 0638 universal time (UT)] near closest approach (0559:03 UT). Angular distributions were highly anisotropic, ordered by the magnetic field, and showed ions arriving from the hemisphere containing Venus and its bow shock. The spectra showed a power law form with intensities observed into the 120- to 280-keV range. Comparisons with model bow shock calculations show that these energetic ions are associated with the venusian foreshock-bow shock region. Shock-drift acceleration in the venusian bow shock seems the most likely process responsible for the observed ions. C1 UNIV ALASKA,FAIRBANKS,AK 99775. MAX PLANCK INST AERON,W-3411 KATLENBURG DUHM,GERMANY. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV KANSAS,LAWRENCE,KS 66044. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP WILLIAMS, DJ (reprint author), JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20707, USA. OI Roederer, Juan/0000-0002-8042-5150 NR 10 TC 9 Z9 9 U1 1 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD SEP 27 PY 1991 VL 253 IS 5027 BP 1525 EP 1528 DI 10.1126/science.253.5027.1525 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GG651 UT WOS:A1991GG65100037 PM 17784094 ER PT J AU MAX, N AF MAX, N TI GRAND SPECTACLES SO NATURE LA English DT Letter RP MAX, N (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 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 SEP 26 PY 1991 VL 353 IS 6342 BP 294 EP 294 DI 10.1038/353294c0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GG654 UT WOS:A1991GG65400021 ER PT J AU COVEY, C AF COVEY, C TI OCEAN UNCERTAINTY SO NATURE LA English DT Letter ID CLIMATE RESPONSE; MODEL; CO2 RP COVEY, C (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV ATMOSPHER & GEOPHYS SCI,LIVERMORE,CA 94551, USA. NR 9 TC 1 Z9 1 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 SEP 26 PY 1991 VL 353 IS 6342 BP 309 EP 310 DI 10.1038/353309c0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA GG654 UT WOS:A1991GG65400040 ER PT J AU PARKER, DH WURZ, P CHATTERJEE, K LYKKE, KR HUNT, JE PELLIN, MJ HEMMINGER, JC GRUEN, DM STOCK, LM AF PARKER, DH WURZ, P CHATTERJEE, K LYKKE, KR HUNT, JE PELLIN, MJ HEMMINGER, JC GRUEN, DM STOCK, LM TI HIGH-YIELD SYNTHESIS, SEPARATION, AND MASS-SPECTROMETRIC CHARACTERIZATION OF FULLERENES C60 TO C266 SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CARBON; C-60; BUCKMINSTERFULLERENE; FORM AB The preparation of fullerenes C60 to C266 in very high yield (up to 44% extractable) by a plasma discharge is reported. Almost one-third of the extractable material is composed of giant fullerenes C84 to C200. An extraction scheme for isolating selected molecular weight fractions of fullerenes is described. The extractions were characterized by time-of-flight mass spectrometry and Fourier transform mass spectrometry. We find that a Soxhlet extraction with benzene extracts 50% more soluble fullerenes than benzene reflux. Soxhlet extractions with 1,2,3,5-tetramethylbenzene preferentially extract higher molecular weight fullerenes. Hexane appears to limit the amount of higher fullerenes extracted, giving solutions containing C60 and C70 with only small traces of the higher molecular weight fullerenes. Heptane extraction following the hexane extraction appears to preferentially extract C60, C70, and C84. This solvent scheme is useful in preparing selected molecular weight fractions for subsequent separation by column chromatography. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 13 TC 193 Z9 194 U1 3 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD SEP 25 PY 1991 VL 113 IS 20 BP 7499 EP 7503 DI 10.1021/ja00020a008 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA GH058 UT WOS:A1991GH05800008 ER PT J AU KELLEY, DG MARCHAJ, A BAKAC, A ESPENSON, JH AF KELLEY, DG MARCHAJ, A BAKAC, A ESPENSON, JH TI FORMATION AND HOMOLYSIS OF ORGANONICKEL(III) COMPLEXES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID AQUEOUS-SOLUTION; RADICAL CATION; KINETICS; ISOMERIZATION; ALKYL; IONS AB The reactions of Ni(1,4,8,11-tetraazacyclotetradecane)2+ with alkyl radicals were studied. Data were collected for the R,R,S,S (or beta) and R,R,R,R (or alpha) isomers. The reactions form sigma-bonded organometallic cations, as in the equation NiL2+ + R. + H2O reversible RNiL(H2O)2+. The values of the rate constants for the forward (colligation) and reverse (homolysis) reactions were measured separately by laser flash photolysis techniques with a kinetic probe. The values of k(col) lie in the order CH3 >> primary >> secondary, and just the reverse order applies to k(hom). Thus the equilibrium constants for formation of RNiL(H2O)2+, given by k(col)/k(hom), are most favorable for methyl and least favorable for secondary alkyls. These nickel-alkyl bonds are much weaker than those in corresponding cobalt and chromium complexes. For that reason, values of k(col) vary widely with the nature of R.. Values of k(col) are considerably higher for alpha-Ni(cyclam)2+ than for the beta-isomer, and the reverse order applies to k(hom). Also, the alpha-isomer has the highest equilibrium constant for the formation equilibrium. The kinetic and thermodynamic trends can be rationalized by structural effects. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 24 TC 36 Z9 36 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 SEP 25 PY 1991 VL 113 IS 20 BP 7583 EP 7587 DI 10.1021/ja00020a020 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA GH058 UT WOS:A1991GH05800020 ER PT J AU GRAY, GT HUANG, JC AF GRAY, GT HUANG, JC TI INFLUENCE OF REPEATED SHOCK LOADING ON THE SUBSTRUCTURE EVOLUTION OF 99.99 WT-PERCENT-ALUMINUM SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID GRAIN-SIZE; DEFORMATION; STRAIN; COPPER; ENERGY AB An electron microscopy study has been conducted of the substructure evolution of large-grained (3 mm) polycrystalline 99.99 wt.% Al subjected to single- and repeated-shock loading excursions at - 180-degrees-C. Single-shock loading of aluminum is seen to form dislocation cells with a high density of vacancy loops. The substructure evolution in aluminum with repeated-shock loading is observed to be progressive in nature and similar to the dislocation arrangements in f.c.c. single crystals and polycrystals with increasing strain. The substructure evolution, from dislocation cells to planar slip bands to microbands, is found to be particularly evident adjacent to grain boundaries. The substructure evolution in high purity aluminum subjected to repeated-shock loading at low temperature is discussed in terms of the deformation mechanisms, in particular vacancy loop and microband formation, and compared with previous studies on shock-deformed aluminum. C1 NATL SUN YAT SEN UNIV,INST MAT SCI & ENGN,KAOHSIUNG,TAIWAN. RP GRAY, GT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. RI Huang, J. /C-4276-2013 NR 67 TC 32 Z9 32 U1 0 U2 9 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD SEP 25 PY 1991 VL 145 IS 1 BP 21 EP 35 DI 10.1016/0921-5093(91)90292-U PG 15 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA GN814 UT WOS:A1991GN81400003 ER PT J AU PEEREY, LM BROTHERS, HM HAZZARD, JT TOLLIN, G KOSTIC, NM AF PEEREY, LM BROTHERS, HM HAZZARD, JT TOLLIN, G KOSTIC, NM TI UNIMOLECULAR AND BIOMOLECULAR OXIDOREDUCTION REACTIONS INVOLVING DIPROTEIN COMPLEXES OF CYTOCHROME-C AND PLASTOCYANIN - DEPENDENCE OF ELECTRON-TRANSFER REACTIVITY ON CHARGE AND ORIENTATION OF THE DOCKED METALLOPROTEINS SO BIOCHEMISTRY LA English DT Article ID BLUE-COPPER PROTEINS; FREE FLAVIN SEMIQUINONES; WATER-SOLUBLE CARBODIIMIDE; FRENCH BEAN PLASTOCYANIN; LASER FLASH-PHOTOLYSIS; REDUCED FREE FLAVINS; CHEMICAL MODIFICATION; SPINACH PLASTOCYANIN; SOLVENT PERTURBATION; TRANSIENT KINETICS AB Cytochrome c and plastocyanin form an electrostatic complex, which can be reinforced by amide bonds in the presence of a carbodiimide. Besides this cross-linking, carbodiimide also converts carboxylate side chains into neutral N-acylurea groups. Four derivatives of the covalent diprotein complex, which differ in the degree of this charge neutralization, are separated by cation-exchange chromatography. Electron-transfer reactions at different ionic strengths involving the electrostatic complex and the four derivatives of the covalent complex are studied by laser flash photolysis with flavin semiquinones as reducing agents. The reactivity of the associated proteins toward external reductants cannot be predicted simply on the basis of this reactivity of the separate proteins. Qualitative analysis of the dependence on ionic strength of the reactions between FMN semiquinone and the covalent derivatives indicates sites at which this reductant interacts with the cross-linked proteins. The surprisingly small steric shielding of the protein redox sites in the covalent complex, as deduced from the reactions at high ionic strength, may indicate that the proteins have multiple reaction domains on their surfaces or that the complex is dynamical or both. The intracomplex (unimolecular) electron-transfer reaction is fast in the electrostatic complex (k(et) = 1300 +/- 200 s-1) but undetectably slow in each of the four derivatives of the covalent complex (k(et) < 0.2 s-1). This reaction apparently requires a migration of cytochrome c from the acidic domain in plastocyanin, which is far from the copper redox site, to the hydrophobic domain, which is near this site. This migration is possible in the electrostatic complex, which is flexible, but impossible in the covalent complex, which contains rigid cross-links. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. UNIV ARIZONA,DEPT BIOCHEM,TUCSON,AZ 85721. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. FU NIDDK NIH HHS [DK15057] NR 75 TC 50 Z9 50 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 24 PY 1991 VL 30 IS 38 BP 9297 EP 9304 DI 10.1021/bi00102a023 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA GG430 UT WOS:A1991GG43000023 PM 1654092 ER PT J AU SHEN, Y RICHARDS, DR HINKS, DG MITCHELL, AW AF SHEN, Y RICHARDS, DR HINKS, DG MITCHELL, AW TI STRUCTURAL MODULATIONS OF BI2SR2CUO6 STUDIED BY INSITU X-RAY-DIFFRACTION SO APPLIED PHYSICS LETTERS LA English DT Article ID CU-O SYSTEM; SUPERCONDUCTING PHASE; SR; FILMS AB High-temperature x-ray diffraction has been carried out on a superconducting single-phase sample of pseudo-tetragonal Bi2Sr2CuO6+y, which was obtained from crystallization of thin glassy platelets. The sample displayed (00l) preferred orientation, which made it possible to determine the incommensurate modulation by conventional theta - 2-theta x-ray scans. The existence of the modulation peaks (800-degrees-C) indicates that the modulation cannot be caused solely by oxygen ordering. As temperature increased, it was observed that a decrease in the intensity of modulation lines was associated with an increase in intensity of fundamental reflection, which was similar to the order-disorder phase transition. By removing 0.045(5) oxygen atom per formula unit, the components of modulation satellites along the b* and c* directions changed from b(mod) = 0.183(9) and c(mod) = 0.315(4) to 0.184(6) and 0.260(4), respectively. This demonstrates that oxygen, while not the sole cause, does play a role in the formation of the structural modulation. However, the invariance of b(mod) with respect to the change in oxygen content does not support the model which explained the modulation by inserting extra oxygen in BiO plane. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NR 24 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 23 PY 1991 VL 59 IS 13 BP 1559 EP 1561 DI 10.1063/1.106282 PG 3 WC Physics, Applied SC Physics GA GG105 UT WOS:A1991GG10500013 ER PT J AU BRYAN, RP OLBRIGHT, GR FU, WS BRENNAN, TM TSAO, JY AF BRYAN, RP OLBRIGHT, GR FU, WS BRENNAN, TM TSAO, JY TI NEAR-INFRARED HIGH-GAIN STRAINED LAYER INGAAS HETEROJUNCTION PHOTOTRANSISTORS - RESONANT PERIODIC ABSORPTION SO APPLIED PHYSICS LETTERS LA English DT Article AB We report high-gain phototransistors on GaAs substrates at wavelengths for which GaAs substrates are transparent, and hence, are promising for optoelectronic interconnect, optical-logic device, neural network, and lightwave communication applications. Using a new technique called resonant periodic absorption we have achieved high-optical gain at previously inaccessible wavelengths (> 925 nm). Resonant periodic absorption is achieved in an asymmetric microresonator consisting of a strained-layer InGaAs/GaAs heterojunction phototransistor sandwiched between distributed Bragg reflectors. By aligning the optical intensity maxima with the InGaAs quantum wells in the collector region of the phototransistor, we dramatically enhance the optical absorption. C1 STANFORD UNIV,SOLID STATE ELECTR LAB,STANFORD,CA 94305. RP BRYAN, RP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 5 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 SEP 23 PY 1991 VL 59 IS 13 BP 1600 EP 1602 DI 10.1063/1.106268 PG 3 WC Physics, Applied SC Physics GA GG105 UT WOS:A1991GG10500028 ER PT J AU BRODSKY, SJ HOYER, P AF BRODSKY, SJ HOYER, P TI NOVEL TESTS OF QUANTUM CHROMODYNAMICS IN ELECTROPRODUCTION SO NUCLEAR PHYSICS A LA English DT Article ID NUCLEUS-NUCLEUS INTERACTIONS; INELASTIC MUON SCATTERING; PRODUCTION CROSS-SECTION; CHARM HADRON PROPERTIES; DRELL-YAN PROCESS; PI-P-INTERACTIONS; 400 GEV PROTONS; A-DEPENDENCE; TRANSVERSE-MOMENTUM; BACKWARD PRODUCTION AB We discuss a number of ways in which single arm and coincident measurements of electroproduction on proton and nuclear targets can test fundamental QCD phenomena and provide constraints on hadronic wavefunctions. The topics include tests of color transparency, predictions for charm production at threshold, formation zone phenomena, and non-additive nuclear effects. We particularly emphasized the need for measurements which probe the short-range structure of hadronic and nuclear wave functions. In addition to the "extrinsic" gluonic and sea-quark contributions associated with radiation from single partons, perturbative QCD predicts an "intrinsic" hardness of the high-mass fluctuations of the wave function. These contributions can dominate heavy particle production at large x in the target fragmentation region and can be further enhanced in nuclear target reactions. Intrinsic hardness can also provide a possible explanation of the anomalous nuclear phenomena referred to as "cumulative production". C1 UNIV HELSINKI, DEPT HIGH ENERGY PHYS, SF-00100 HELSINKI 10, FINLAND. RP STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94305 USA. NR 111 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 23 PY 1991 VL 532 IS 1-2 BP C79 EP C102 PG 24 WC Physics, Nuclear SC Physics GA GL484 UT WOS:A1991GL48400008 ER PT J AU CLOSE, FE AF CLOSE, FE TI FROM QUARKS (OR ANTIQUARKS AND GLUONS) INTO HADRONS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 2ND EUROPEAN WORKSHOP ON HADRONIC PHYSICS WITH ELECTRONS BEYOND 10 GEV CY OCT 07-12, 1990 CL DOURDAN, FRANCE SP CEA, CNRS, INT UNION PURE & APPL PHYS, INT COMM HIGH INTENS ACCERATORS, NUCL PHYS EUROPEAN COLLABORAT COMM ID SPIN; SCATTERING; PROTON; NUCLEON AB This is the talk summarising the discussions in the session titled "From Quarks into Hadrons". C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. UNIV TENNESSEE,KNOXVILLE,TN 37996. RP CLOSE, FE (reprint author), RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 23 PY 1991 VL 532 IS 1-2 BP C25 EP C34 PG 10 WC Physics, Nuclear SC Physics GA GL484 UT WOS:A1991GL48400004 ER PT J AU GARVEY, GT AF GARVEY, GT TI THE A-DEPENDENCE OF DILEPTON PRODUCTION SO NUCLEAR PHYSICS A LA English DT Article ID LEPTON-PAIR PRODUCTION; DRELL-YAN PROCESS; NUCLEI; IRON; COLLISIONS; SEA RP UNIV CALIF LOS ALAMOS SCI LAB, MS H846, LOS ALAMOS, NM 87545 USA. NR 18 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 23 PY 1991 VL 532 IS 1-2 BP C119 EP C132 PG 14 WC Physics, Nuclear SC Physics GA GL484 UT WOS:A1991GL48400010 ER PT J AU GOLDMAN, T AF GOLDMAN, T TI INEVITABLE DIBARYONS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 2ND EUROPEAN WORKSHOP ON HADRONIC PHYSICS WITH ELECTRONS BEYOND 10 GEV CY OCT 07-12, 1990 CL DOURDAN, FRANCE SP CEA, CNRS, INT UNION PURE & APPL PHYS, INT COMM HIGH INTENS ACCERATORS, NUCL PHYS EUROPEAN COLLABORAT COMM ID QUARK-MODEL; BAG MODEL; STATES; QCD RP GOLDMAN, T (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 14 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 23 PY 1991 VL 532 IS 1-2 BP C389 EP C394 PG 6 WC Physics, Nuclear SC Physics GA GL484 UT WOS:A1991GL48400035 ER PT J AU VANBIBBER, K AF VANBIBBER, K TI ELECTROPRODUCTION AT LARGE MOMENTUM-TRANSFERS SO NUCLEAR PHYSICS A LA English DT Article ID COMPTON-SCATTERING; PERTURBATIVE QCD; TRANSPARENCY; NUCLEI AB The possibilities of electroproduction experiments at a facility such as the proposed European electron accelerator are discussed. Examples given are from studies of hadronization, color transparency, backward production, virtual Compton scattering and target spectator decay. Some conclusions about machine parameters are drawn. RP VANBIBBER, K (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, POB 808, LIVERMORE, CA 94550 USA. NR 30 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 23 PY 1991 VL 532 IS 1-2 BP C195 EP C214 PG 20 WC Physics, Nuclear SC Physics GA GL484 UT WOS:A1991GL48400015 ER PT J AU GOCKSCH, A AF GOCKSCH, A TI CHIRAL SYMMETRY IN HOT QCD SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUARK-NUMBER SUSCEPTIBILITY; HADRONIC SCREENING LENGTHS; FINITE TEMPERATURE; QUANTUM CHROMODYNAMICS; GLUON PLASMA; SIGMA-MODEL; TRANSITION AB Recent lattice calculations of static hadronic screening lengths and the quark number susceptibility are interpreted in terms of a simple constituent quark model. The conclusion is that just above T(c) the nature of the hadronic modes is rather well described in terms of elementary pi and sigma, as well as light quark, modes. Hence chiral symmetry in the absence of symmetry breaking terms is realized through massless quarks rather than through parity doubling. RP GOCKSCH, A (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 33 TC 55 Z9 55 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 23 PY 1991 VL 67 IS 13 BP 1701 EP 1704 DI 10.1103/PhysRevLett.67.1701 PG 4 WC Physics, Multidisciplinary SC Physics GA GG106 UT WOS:A1991GG10600008 ER PT J AU DIMONTE, G WILEY, LG AF DIMONTE, G WILEY, LG TI DYNAMICS OF EXPLODING PLASMAS IN A MAGNETIC-FIELD SO PHYSICAL REVIEW LETTERS LA English DT Article ID INSTABILITY AB The expansion of laser-ablation plasmas in a magnetic field is studied with a new Faraday-rotation magnetic imaging probe and Fourier-analyzed optical plasma images over a wide range of ion magnetization. Plasma instabilities are observed during the plasma expansion which evolve from short to long wavelengths and significantly affect the magnetic structure. RP DIMONTE, G (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 11 TC 66 Z9 67 U1 0 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 23 PY 1991 VL 67 IS 13 BP 1755 EP 1758 DI 10.1103/PhysRevLett.67.1755 PG 4 WC Physics, Multidisciplinary SC Physics GA GG106 UT WOS:A1991GG10600022 ER EF