FN Thomson Reuters Web of Science™ VR 1.0 PT J AU BRAMBLE, JH PASCIAK, JE WANG, JP XU, JC AF BRAMBLE, JH PASCIAK, JE WANG, JP XU, JC TI CONVERGENCE-ESTIMATES FOR MULTIGRID ALGORITHMS WITHOUT REGULARITY ASSUMPTIONS SO MATHEMATICS OF COMPUTATION LA English DT Article AB A new technique for proving rate of convergence estimates of multigrid algorithms for symmetric positive definite problems will be given in this paper. The standard multigrid theory requires a "regularity and approximation" assumption. In contrast, the new theory requires only an easily verified approximation assumption. This leads to convergence results for multigrid refinement applications, problems with irregular coefficients, and problems whose coefficients have large jumps. In addition, the new theory shows why it suffices to smooth only in the regions where new nodes are being added in multigrid refinement applications. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. UNIV WYOMING,DEPT MATH,LARAMIE,WY 82071. PENN STATE UNIV,DEPT MATH,UNIVERSITY PK,PA 16802. RP BRAMBLE, JH (reprint author), CORNELL UNIV,DEPT MATH,ITHACA,NY 14853, USA. NR 23 TC 151 Z9 152 U1 0 U2 1 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0025-5718 J9 MATH COMPUT JI Math. Comput. PD JUL PY 1991 VL 57 IS 195 BP 23 EP 45 DI 10.2307/2938661 PG 23 WC Mathematics, Applied SC Mathematics GA FZ449 UT WOS:A1991FZ44900002 ER PT J AU MUSOLINO, SV MCGINLEY, PH GREENWOOD, RC KLIAUGA, P FAIRCHILD, RG AF MUSOLINO, SV MCGINLEY, PH GREENWOOD, RC KLIAUGA, P FAIRCHILD, RG TI EVALUATION OF AN IRON-FILTERED EPITHERMAL NEUTRON BEAM FOR NEUTRON-CAPTURE THERAPY SO MEDICAL PHYSICS LA English DT Article ID RADIOTHERAPY AB An epithermal neutron filter using iron, aluminum, and sulfur was evaluated to determine if the therapeutic performance could be improved with respect to aluminum-sulfur-based filters. An empirically optimized filter was developed that delivered a 93% pure beam of 24-keV epithermal neutrons. It was expected that a thick filter using iron with a density thickness > 200 g/cm2 would eliminate the excess gamma contamination found in Al-S filters. This research showed that prompt gamma production from neutron interactions in iron was the dominant dose component. Dosimetric parameters of the beam were determined from the measurement of absorbed dose in air, thermal neutron flux in a head phantom, neutron and gamma spectroscopy, and microdosimetry. C1 GEORGIA INST TECHNOL,ATLANTA,GA 30332. IDAHO NATL ENGN LAB,IDAHO FALLS,ID. COLUMBIA UNIV COLL PHYS & SURG,NEW YORK,NY 10032. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP MUSOLINO, SV (reprint author), BROOKHAVEN NATL LAB,DIV SAFETY & ENVIRONM PROTECT,UPTON,NY 11973, USA. NR 29 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 0094-2405 J9 MED PHYS JI Med. Phys. PD JUL-AUG PY 1991 VL 18 IS 4 BP 806 EP 816 DI 10.1118/1.596635 PG 11 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA GB235 UT WOS:A1991GB23500020 PM 1656179 ER PT J AU COUTRAKON, G MILLER, D KROSS, BJ ANDERSON, DF DELUCA, P SIEBERS, J AF COUTRAKON, G MILLER, D KROSS, BJ ANDERSON, DF DELUCA, P SIEBERS, J TI A BEAM INTENSITY MONITOR FOR THE LOMA LINDA CANCER-THERAPY PROTON ACCELERATOR SO MEDICAL PHYSICS LA English DT Article DE PROTON MEDICAL ACCELERATOR; BEAM INTENSITY MONITOR; GAS SCINTILLATOR AB A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 10(10) and 10(11) protons per spill. A beam spill is typically 1 s long with a 2-s repetition period. The intensity monitor must be radiation hard, expose minimum mass to the beam, and measure intensity to 1% in 1-ms time intervals. To this end, a 5-cm-thick xenon gas scintillator optically coupled to a photomultiplier tube (PMT) was tested to measure its response to the proton beam. The gas cell was operated at 1.2 atm of pressure and has 12.7-mu-m-thick titanium entrance and exit foils. The total mass exposed to the beam is 0.14 g/cm2 and is dominated by the titanium windows. This mass corresponds to a range attenuation equal to 1.4 mm of water. The energy lost to the xenon gas is about 70 keV per proton. Each passing proton will produce approximately 2000 photons. With a detection efficiency on the order of 0.05% for this UV light, one would anticipate over 10(10) photoelectrons per second. In a 1-ms time bin there will be approximately 10(7) photoelectrons. This yields a resolution limited by systematics. For unregulated 0.4-s proton spills, we observe a response bandwidth in excess of 10(4) Hz. While signal-to-noise and linearity were not easily measured, we estimate as few as 10(3) protons can be observed suggesting a dynamic range in excess of 10(5) is available. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV WISCONSIN,DEPT MED PHYS,MADISON,WI 53706. RP COUTRAKON, G (reprint author), LOMA LINDA UNIV,MED CTR,LOMA LINDA,CA 92354, USA. NR 11 TC 6 Z9 6 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0094-2405 J9 MED PHYS JI Med. Phys. PD JUL-AUG PY 1991 VL 18 IS 4 BP 817 EP 820 DI 10.1118/1.596636 PG 4 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA GB235 UT WOS:A1991GB23500021 PM 1656180 ER PT J AU MORRISON, DJ JONES, JW ALEXANDER, DE WAS, GS AF MORRISON, DJ JONES, JW ALEXANDER, DE WAS, GS TI INFLUENCE OF CYCLIC DEFORMATION ON SURFACE MICROSTRUCTURE AND HARDNESS OF ION-IMPLANTED NICKEL SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID FATIGUE CRACK INITIATION; COPPER SINGLE-CRYSTALS; PERSISTENT SLIP BANDS; POLYCRYSTALLINE COPPER; STAINLESS-STEEL; LIFE; BEHAVIOR; METALS; ALLOY; INDENTATION AB The effects of cyclic deformation on near-surface dislocation structure and hardness of ion-implanted nickel were characterized and correlated with the evolution of fatigue damage. Polycrystalline nickel fatigue specimens were implanted at 220-degrees-C with 350 keV and 3 MeV nickel ions to a fluence of 1 X 10(16) ions/cm2 or at 220-degrees-C and 500-degrees-C with 350 keV aluminum ions to a fluence of 5 x 10(17) ions/cm2. Both the self-implantations and aluminum implantations approximately doubled the hardness of the near-surface region. During cyclic deformation, the near-surface regions of self-implanted specimens cyclically softened and formed clear channels through which subsurface persistent slip bands (PSBs) penetrated the implanted region. The near-surface regions of aluminum-implanted specimens maintained a high hardness during cyclic deformation and effectively suppressed the evolution of fatigue damage and extended fatigue life. The results of the study indicate that the cyclic stability of implantation-induced surface hardening is a key factor in the ability of an ion implantation treatment to suppress the evolution of fatigue damage. C1 UNIV MICHIGAN,DEPT MAT SCI & ENGN,ANN ARBOR,MI 48109. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109. RP MORRISON, DJ (reprint author), CLARKSON UNIV,DEPT MECH & AERONAUT ENGN,POTSDAM,NY 13699, USA. NR 46 TC 8 Z9 8 U1 2 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD JUL PY 1991 VL 22 IS 7 BP 1633 EP 1646 DI 10.1007/BF02667376 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA FV349 UT WOS:A1991FV34900016 ER PT J AU SCHREMS, KK AF SCHREMS, KK TI USE OF DIFFERENTIAL INTERFERENCE CONTRAST MICROSCOPY TO DETECT DUPLEX CARBIDES IN ALLOY WHITE CAST IRONS SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Note RP SCHREMS, KK (reprint author), US BUR MINES,ALBANY RES CTR,ALBANY,OR 97321, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD JUL PY 1991 VL 22 IS 7 BP 1673 EP 1674 DI 10.1007/BF02667379 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA FV349 UT WOS:A1991FV34900019 ER PT J AU APPLETON, BR AF APPLETON, BR TI PRIORITIES IN SCIENCE SO MRS BULLETIN LA English DT Article RP APPLETON, BR (reprint author), OAK RIDGE NATL LAB,PHYS SCI & ADV MAT,OAK RIDGE,TN 37830, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0883-7694 J9 MRS BULL JI MRS Bull. PD JUL PY 1991 VL 16 IS 7 BP 5 EP & PG 0 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FX207 UT WOS:A1991FX20700001 ER PT J AU BUONARATI, MH TUCKER, JD MINKLER, JL WU, RW THOMPSON, LH FELTON, JS AF BUONARATI, MH TUCKER, JD MINKLER, JL WU, RW THOMPSON, LH FELTON, JS TI METABOLIC-ACTIVATION AND CYTOGENETIC EFFECTS OF 2-AMINO-1-METHYL-6-PHENYLIMIDAZO[4,5-B] PYRIDINE (PHIP) IN CHINESE-HAMSTER OVARY CELLS EXPRESSING MURINE CYTOCHROME-P450 IA2 SO MUTAGENESIS LA English DT Article ID FOOD MUTAGEN 2-AMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE; ANEUPLOIDY-INDUCING AGENTS; SISTER CHROMATIDS; LIVER-MICROSOMES; CHO CELLS; DNA; GENOTOXICITY; RABBIT; CDNA AB We have utilized Chinese hamster ovary cell lines which stably express a murine cytochrome P450IA2 (P(3)450) cDNA to characterize more fully the mechanisms of genotoxicity of heterocyclic amines derived from cooked meats. To verify that these cell lines were capable of converting promutagens into active metabolites, we studied the microsomal metabolism and cytogenetic effects of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Microsomal preparations derived from excision repair-deficient Chinese hamster ovary cells expressing the mouse cytochrome P(3)450 cDNA (UV5P3) converted PhIP to the genotoxic N-hydroxy-PhIP metabolite. Cytotoxic activity in UV5P3 was observed at concentrations of PhIP as low as 1-mu-M. Cytotoxicity of PhIP was an order of magnitude lower in a matched repair-proficient cell line (5P3R2) expressing the P(3)450 cDNA. PhIP produced a concentration-dependent increase in sister chromatid exchange (SCE) in UV5P3. N-Hydroxy-PhIP, at concentrations as low as 0.1-mu-M, produced an increase in SCE in both UV5P3 and in UV5 cells which lack the P(3)450 cDNA. Incubation of PhIP with UV5P3 cells increased the frequency of micronuclei (MN) in cytokinesis-blocked cells. Chromatid gaps, but not aberrations also were induced by treatment with PhIP. N-Hydroxy-PhIP produced increases in MN and chromatid gaps in both UV5 and UV5P3 cell lines; chromosomal aberrations were induced in UV5P3 cells. These results suggested that UV5P3 cells metabolize sufficient quantities of PhIP to produce cytogenetic damage and further indicated that N-hydroxylation of PhIP was requisite for mammalian genotoxicity. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,L-452,POB 5507,LIVERMORE,CA 94550. FU NIEHS NIH HHS [222YO1-ES-70158] NR 24 TC 38 Z9 38 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0267-8357 J9 MUTAGENESIS JI Mutagenesis PD JUL PY 1991 VL 6 IS 4 BP 253 EP 259 DI 10.1093/mutage/6.4.253 PG 7 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FY453 UT WOS:A1991FY45300003 PM 1943715 ER PT J AU MILLER, BM ZITZELSBERGER, HF WEIER, HUG ADLER, ID AF MILLER, BM ZITZELSBERGER, HF WEIER, HUG ADLER, ID TI CLASSIFICATION OF MICRONUCLEI IN MURINE ERYTHROCYTES - IMMUNOFLUORESCENT STAINING USING CREST ANTIBODIES COMPARED TO INSITU HYBRIDIZATION WITH BIOTINYLATED GAMMA SATELLITE DNA SO MUTAGENESIS LA English DT Article ID POSSIBLE HUMAN CARCINOGENS; SUSPECT SPINDLE POISONS; BONE-MARROW CELLS; MITOMYCIN-C; MOUSE SPERMATOGONIA; CHROMOSOME ANALYSIS; HUMAN CENTROMERE; CHINESE-HAMSTER; ASSAY; KINETOCHORE AB Micronuclei (MN in erythrocytes of mouse bone marrow cells were induced in vivo by the spindle poisons colchicine (COL) and vinblastine (VBL), by hydroquinone (HQ) and by the alkylating agent mitomycin C (MMC). Two different methods were applied to detect whole chromosomes with centromeric proteins or chromatin in MN to discriminate between spindle damaging or clastogenic activity of these chemicals. One method determined the fraction of MN with centromeric chromatin by immunofluorescent staining using antikinetochore antibodies (CREST staining). The other method applied non-radioactive in situ hybridization with a novel DNA probe. The fractions of MN that showed positive signals by either technique thus indicating with a high probability the presence of whole chromosomes instead of acentric fragments, were in good agreement for COL, VBL and HQ. After application of MMC, however, 4.5% of the MN were CREST-positive, while 29% gave a positive hybridization signal. The results suggest, that kinetochores may have lost certain centromeric antigens due to treatment with MMC so that MN containing whole chromosomes appear CREST-negative. The presented in situ hybridization scheme using satellite DNA is a more direct detection and is advantageous to the CREST staining technique in that it is unaffected by damage of kinetochore or centromeric function. C1 GESELL STRAHLEN & UMWELTFORSCH MBH,FORSCHUNGSZENTRUM UMWELT & GESUNDHEIT GMBH,INST STRAHLENBIOL,W-8042 NEUHERBERG,GERMANY. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. RP MILLER, BM (reprint author), GESELL STRAHLEN & UMWELTFORSCH MBH,FORSCHUNGSZENTRUM UMWELT & GESUNDHEIT GMBH,INST AUGETIERGENET,D-8042 NEUHERBERG,FED REP GER. NR 46 TC 110 Z9 111 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0267-8357 J9 MUTAGENESIS JI Mutagenesis PD JUL PY 1991 VL 6 IS 4 BP 297 EP 302 DI 10.1093/mutage/6.4.297 PG 6 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FY453 UT WOS:A1991FY45300009 PM 1719336 ER PT J AU LEADON, SA LAWRENCE, DA AF LEADON, SA LAWRENCE, DA TI PREFERENTIAL REPAIR OF DNA DAMAGE ON THE TRANSCRIBED STRAND OF THE HUMAN METALLOTHIONEIN GENES REQUIRES RNA POLYMERASE-II SO MUTATION RESEARCH LA English DT Article DE PYRIMIDINE DIMERS; AFLATOXIN-B1; CHROMATIN; MONOCLONAL ANTIBODY; PREFERENTIAL DNA REPAIR ID DIFFERENTIAL REPAIR; MONKEY CELLS; XERODERMA PIGMENTOSUM; NUCLEOTIDE-SEQUENCES; COCKAYNES SYNDROME; PROCESSED GENE; ACTIVE GENE; DHFR GENE; ALPHA-DNA; INHIBITION AB To examine the possible role of transcription in directing repair of DNA damage in active genes, we compared repair of UV- and aflatoxin B1-induced damage on each strand of the human metallothionein (hMT) genes. Repair on the transcribed strand of an active hMT gene occurs at least 3 times faster than that on its nontranscribed strand. Both strands of inactive genes and both strands of a regulatory region 5' to an active gene are not repaired at this faster rate. Inducing higher levels of transcription with dexamethasone selectively increased the rate of repair on only the transcribed strand of the induced gene, while treatment of cells with alpha-amanitin eliminated the strand-selective repair. These results demonstrate that repair on the transcribed strand of a gene is independent of repair on the nontranscribed strand and that the transcriptional complex plays a role in directing repair to the transcribed strand of active genes. RP LEADON, SA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720, USA. FU NCI NIH HHS [CA 40453] NR 44 TC 99 Z9 99 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD JUL PY 1991 VL 255 IS 1 BP 67 EP 78 DI 10.1016/0921-8777(91)90019-L PG 12 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA FW092 UT WOS:A1991FW09200008 PM 1906131 ER PT J AU BANDYOPADHYAY, K HOFMAYER, C AF BANDYOPADHYAY, K HOFMAYER, C TI COMPONENT FRAGILITY RESULTS FOR RELIABILITY AND PROBABILITY STUDIES SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article; Proceedings Paper CT 10TH MEETING OF THE DIVISION ON STRUCTURAL RELIABILITY OF THE CONF ON STRUCTURAL MECHANICS IN REACTOR TECHNOLOGY ( SMIRT-10 ) CY AUG 14-18, 1989 CL ANAHEIM, CA AB Under a sponsorship of the United States Nuclear Regulatory Commission (NRC), Brookhaven National Laboratory (BNL) has formed a test data base of seismic fragility of nuclear power plant equipment and analyzed the data for use in reliability and probability studies. This paper describes the data base and discusses the analysis methods and results. A large sample of test data has been collected from various sources for the data base. A standardization technique has been applied for conversion of the data to a uniform and consistent data set. The zero period acceleration (ZPA) and the average spectral acceleration (ASA) over the 4-16 Hz frequency range have been selected to represent a test response spectrum and these two parameters have been used in the statistical analysis. A logarithmic distribution of the data has been assumed. Test data of six classes of equipment have been analyzed. For each equipment type, the median value, the coefficients of variance and a high confidence (95%) value corresponding to a low probability (5%) of failure have been computed. These results are obtained for both the ZPA and ASA fragility parameters and for different failure modes. The fragility results are expected to provide a strong basis for future reliability and probability studies. The data base at BNL is being expanded by collection of test information for additional equipment categories. RP BANDYOPADHYAY, K (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 11 TC 0 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD JUL PY 1991 VL 128 IS 2 BP 217 EP 225 DI 10.1016/0029-5493(91)90103-O PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GD455 UT WOS:A1991GD45500007 ER PT J AU EBADIAN, MA YANG, G BIGZADEH, E WALKER, JF ABRAHAM, TJ AF EBADIAN, MA YANG, G BIGZADEH, E WALKER, JF ABRAHAM, TJ TI MATHEMATICAL-MODELING OF LIQUID WASTE EVAPORATION FROM THE MELTON VALLEY STORAGE TANKS USING HEAT AND MASS-TRANSFER IN A BUBBLE CHAIN SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article ID COLUMN; PREDICTION AB A mathematical model is presented for evaporating waste from the Melton Valley Storage Tanks (MVSTs) at Oak Ridge National Laboratory. This paper shows that the evaporation of liquid waste from the MVSTs is a viable option for increasing the available waste storage volume over a significant time period. The evaporation process has been modeled using mass and heat transfer through the formation of a bubble chain. This bubble chain is formed by sparging air through five 1-in. diam pipes. The sparged air is then dispersed inside a tank with a 50000 gal waste capacity. This paper discusses in detail the bubble formation. velocity of rise and the correlation obtained, and how it is used for heat- and mass-transfer analysis- The mathematical model is then used to compute the vapor concentration in milligrams per liter inside the tanks and in the associated piping system. These findings, along with the experimental measurements from the pilot plant, are illustrated in tabular and graphical form. The accuracy of the mathematical model was verified using data from a laboratory-scale experimental system. Comparison of these results indicates an excellent agreement for liquid water and synthetic waste. In addition, the evaporation rate and the number of tanks required are plotted against the sparging air temperature for dehumidified air, as well as for different mass flow rates and the significance of these curves is also discussed. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RP EBADIAN, MA (reprint author), FLORIDA INT UNIV,DEPT MECH ENGN,MIAMI,FL 33199, USA. NR 23 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD JUL PY 1991 VL 128 IS 3 BP 305 EP 315 DI 10.1016/0029-5493(91)90168-H PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GD457 UT WOS:A1991GD45700003 ER PT J AU BAYLOR, LR HOULBERG, WA MILORA, SL SCHMIDT, GL KUPSCHUS, P AF BAYLOR, LR HOULBERG, WA MILORA, SL SCHMIDT, GL KUPSCHUS, P TI PARTICLE-TRANSPORT IN PELLET FUELED JET PLASMAS SO NUCLEAR FUSION LA English DT Article ID TOKAMAK AB Multipellet fuelling experiments have been performed on the Joint European Torus (JET) and the resulting density profile evolution has been analysed. A local particle transport analysis is carried out using a 1 1/2-D radial particle transport code to model the experimentally determined evolution of the electron density profile. Plasmas in the limiter configuration, with Ohmic heating, ion cyclotron resonance frequency (ICRF) heating and neutral beam injection are analysed. Ohmic and ICRF heated discharges with peaked density profiles generated by deep pellet penetration are usually characterized by a low core particle diffusivity and can be satisfactorily modelled without any anomalous convective (pinch) term. The evolution of the density profile in auxiliary heated discharges with enhanced levels of magnetohydrodynamic fluctuations shows a rapid decay of the peaked central density that can be modelled with a temperature dependent increase in the diffusivity. Particle balance calculations of effective particle diffusivity in the core region yield values as low as 0.04 m2/s in discharges with highly peaked density profiles. The determined particle diffusivity in all cases is 10-100 times larger than the neoclassical diffusivity. The dependence of the particle diffusivity on density profile peakedness correlates well with the effective thermal diffusivity from power balance calculations. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544. JOINT EUROPEAN TORUS,JOINT UNDERTAKING,ABINGDON,OXON,ENGLAND. RP BAYLOR, LR (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 21 TC 15 Z9 15 U1 2 U2 3 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1991 VL 31 IS 7 BP 1249 EP 1259 DI 10.1088/0029-5515/31/7/002 PG 11 WC Physics, Fluids & Plasmas SC Physics GA FY483 UT WOS:A1991FY48300002 ER PT J AU SACKS, RA WILLIAMS, EA AF SACKS, RA WILLIAMS, EA TI CONSTRAINT ON THE RESIDUAL-GAS DENSITY IN LASER FUSION TARGET CHAMBERS DUE TO STIMULATED RAMAN-SCATTERING SO NUCLEAR FUSION LA English DT Article AB For laser propagation through an inertial confinement fusion reactor target chamber there is a maximum for the allowable gas density and hence for the shot repetition rate in the chamber. Small angle forward stimulated Raman scattering (SRS) is an important process in limiting the propagation and setting this constraint. A conservative model - propagation of the laser beam through a uniform plasma with the plasma wave amplitude determined by saturation due to electron trapping - leads to a fractional energy loss which scales as the square of the wavelength and is independent of intensity. For a 10 MJ target in an argon atmosphere, it is expected that the onset of substantial energy loss will occur very abruptly as the gas density increases beyond about 10(16) cm-3; for a LiF/BeF2 atmosphere, the acceptable density of LiF molecules may be about a factor of three smaller (3 x 10(15) cm-3). If the ionization of the background gas is dominated by photoionization due to X-rays emitted from the target (after heating by the early part of the laser pulse). then the 1/r2 plasma density gradient is effective in stabilizing the growth of SRS. This stabilization leads to a substantial increase in the allowable density. RP SACKS, RA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 4 TC 0 Z9 0 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 JUL PY 1991 VL 31 IS 7 BP 1343 EP 1347 DI 10.1088/0029-5515/31/7/009 PG 5 WC Physics, Fluids & Plasmas SC Physics GA FY483 UT WOS:A1991FY48300009 ER PT J AU CHRIEN, RE FERNANDEZ, JC HENINS, I MAYO, RM WYSOCKI, FJ AF CHRIEN, RE FERNANDEZ, JC HENINS, I MAYO, RM WYSOCKI, FJ TI EVIDENCE FOR RUNAWAY ELECTRONS IN A SPHEROMAK PLASMA SO NUCLEAR FUSION LA English DT Letter ID RELAXATION AB The first evidence for runaway electrons in a spheromak plasma is presented; it is based on the observation of hard X-ray emission with an energy of about 1 MeV. The hard X-rays are produced in one or more bursts occurring early in the spheromak decay phase, after the coaxial plasma gun voltage is turned off. No obvious correlation is found between the amplitude of the hard X-ray emission and other spheromak parameters. Since there is no direct acceleration mechanism for electrons to reach MeV energy levels, these observations imply that the runaway electrons are confined for an acceleration time of greater-than-or-equal-to 20-50-mu-s and a path length of greater-than-or-equal-to 5-10 km, assuming that the electrons are accelerated in the electric field of the decaying spheromak. RP CHRIEN, RE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. RI Fernandez, Juan/H-3268-2011 OI Fernandez, Juan/0000-0002-1438-1815 NR 10 TC 5 Z9 5 U1 3 U2 6 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD JUL PY 1991 VL 31 IS 7 BP 1390 EP 1393 DI 10.1088/0029-5515/31/7/015 PG 4 WC Physics, Fluids & Plasmas SC Physics GA FY483 UT WOS:A1991FY48300015 ER PT J AU DOWELL, DH LAUCKS, ML LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K MILLIMAN, L LANCASTER, C ADAMSKI, J PISTORESI, D SHOFFSTALL, DR BENTZ, M BURNS, R GUHA, J HUDYMA, R SUN, K TOMITA, W MOWER, W BENDER, S GOLDSTEIN, J LUMPKIN, AH MCVEY, B TOKAR, R SHEMWELL, D AF DOWELL, DH LAUCKS, ML LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K MILLIMAN, L LANCASTER, C ADAMSKI, J PISTORESI, D SHOFFSTALL, DR BENTZ, M BURNS, R GUHA, J HUDYMA, R SUN, K TOMITA, W MOWER, W BENDER, S GOLDSTEIN, J LUMPKIN, AH MCVEY, B TOKAR, R SHEMWELL, D TI 1ST OPERATION OF A FREE-ELECTRON LASER USING A RING RESONATOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID SIMULATIONS AB During the past year the Boeing free electron laser optical cavity was changed from a simple concentric cavity using two spherical mirrors to a much larger ring resonator. The new resonator is made up of two-mirror telescopes located at each end of the wiggler with a round-trip path length of approximately 133 m. Each telescope consists of a grazing-incidence hyperboloid and a paraboloid. First lasing operation at 0.63-mu-m occurred on March 23 and 24, 1990. The lasing output was approximately seven orders of magnitude above the outcoupled spontaneous emission. The characteristics of the ring resonator are discussed. Lasing data is analyzed for the electron beam and ring resonator effects. Optical alignment techniques for the ring resonator are presented. C1 ROCKWELL INT CORP,ROCKETDYNE DIV,CANOGA PK,CA 91304. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. SPECTRA TECHNOL INC,BELLEVUE,WA. BOEING CO,PHYS SCI RES CTR,SEATTLE,WA 98124. RP DOWELL, DH (reprint author), BOEING AEROSP & ELECTR,SEATTLE,WA 98124, USA. NR 12 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 1 EP 11 DI 10.1016/0168-9002(91)90810-D PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500002 ER PT J AU LAUCKS, ML DOWELL, DH LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K ADAMSKI, J PISTORESI, D SHOFFSTALL, DR BENTZ, M BURNS, R HUDYMA, R SUN, K MOWER, W BENDER, S GOLDSTEIN, J LUMPKIN, A MCVEY, B TOKAR, R SHEMWELL, D AF LAUCKS, ML DOWELL, DH LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K ADAMSKI, J PISTORESI, D SHOFFSTALL, DR BENTZ, M BURNS, R HUDYMA, R SUN, K MOWER, W BENDER, S GOLDSTEIN, J LUMPKIN, A MCVEY, B TOKAR, R SHEMWELL, D TI OPTICAL MEASUREMENTS ON THE BOEING FREE-ELECTRON LASER RING RESONATOR EXPERIMENT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FEL OSCILLATOR AB The Boeing free electron laser is presently operating with a stable semiconfocal ring optical cavity surrounding a 5 m wiggler. The resonator consists of two grazing-incidence reflective telescopes each formed by a grazing-incidence hyperboloid and its companion off-axis paraboloid. The resonator is closed by two flats: one used for dynamic jitter correction and the other used to outcouple some of the circulating beam. It is critical to lasing that the alignment of the resonator be maintained, the focus of the optical mode be at the midpoint of the wiggler, and the wavefront quality of the propagating beam be maintained. Measurements of the focus position, power loss, and wavefront quality are made before operation of the electron accelerator to diagnose whether the conditions required for lasing exist. C1 ROCKWELL INT CORP,ROCKETDYNE DIV,CANOGA PK,CA 91304. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. SPECTRA TECHNOL INC,SEATTLE,WA. RP LAUCKS, ML (reprint author), BOEING AEROSP & ELECTR,SEATTLE,WA 98124, USA. NR 6 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 25 EP 30 DI 10.1016/0168-9002(91)90814-7 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500006 ER PT J AU LUMPKIN, AH AF LUMPKIN, AH TI THE NEXT GENERATION OF RF FEL (FREE-ELECTRON LASER) DIAGNOSTICS - SYNCHROSCAN AND DUAL-SWEEP STREAK CAMERA TECHNIQUES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB Time-resolved experiments on rf-linac driven free electron laser (FEL) experiments have recently been extended to displaying both the submicropulse and submacropulse effects. By using a synchroscan sweep on a streak camera, key rf phase effects can be studied, and an additional dual sweep feature can provide this information during the macropulse. Successful measurements to date on the Los Alamos and the Boeing FELs include electron-beam micropulse bunching during a macropulse, phase stability effects, micropulse elongation and transit time in a photo-injector, drive-laser phase stability and FEL output evolution. Several of these measurements are the first of their kind on a FEL system. RP LUMPKIN, AH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 7 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 31 EP 36 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500007 ER PT J AU TANABE, T TEICH, MC MARSHALL, TC GALAYDA, J AF TANABE, T TEICH, MC MARSHALL, TC GALAYDA, J TI MEASUREMENT OF PHOTON STATISTICS OF WIGGLER RADIATION FROM AN ELECTRON STORAGE RING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID LASER; NOISE; SHOT; RADIOLUMINESCENCE; COHERENCE; GLASS; LIGHT AB The number of visible photons emitted by an electron bunch moving through a wiggler in the Brookhaven Synchrotron Light Source storage ring was repetitively measured using an analog photon counting technique, and the photon counting distribution, which is the probability of finding n photons versus n, was obtained. The photoelectron-counting distribution of detected spontaneous light from the wiggler obeys a negative-binomial distribution consistent with a multi-electron, multimode description of the light generation process. In the absence of the wiggler, the bending-magnet light emerging from the pyrex exit port obeys the Neyman type-A distribution. C1 COLUMBIA UNIV,DEPT ELECT ENGN,NEW YORK,NY 10027. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973. RP TANABE, T (reprint author), COLUMBIA UNIV,DEPT APPL PHYS,NEW YORK,NY 10027, USA. NR 20 TC 11 Z9 11 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 77 EP 80 DI 10.1016/0168-9002(91)90824-A PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500016 ER PT J AU KIM, KJ XIE, M AF KIM, KJ XIE, M TI STABILITY AND PERFORMANCE OF CDRL-FEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON LASER; SIDEBAND SUPPRESSION; WIGGLER AB We study the performance of a proposed infrared free electron laser at the Lawrence Berkeley Laboratory, which would be a user facility and therefore has a unique set of requirements in intensity, spectrum and stability. The output performance in intensity and spectrum, and methods to optimize the performance, are studied in detail. The effect of the electron beam fluctuation on FEL stability is carefully evaluated to set a tolerance for the accelerator design. Use of intracavity gratings is studied as a means of further improving the spectral purity and stability. RP KIM, KJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 20 TC 12 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 146 EP 154 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500030 ER PT J AU BENZVI, I DIMAURO, LF KRINSKY, S WHITE, MG YU, LH AF BENZVI, I DIMAURO, LF KRINSKY, S WHITE, MG YU, LH TI PROPOSED UV FEL USER FACILITY AT BNL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID AMPLIFIER AB The NSLS at Brookhaven National Laboratory is proposing the construction of an UV FEL operating in the wavelength range from visible to 1000 angstrom. Nanocoulomb electron pulses will be generated at a laser photocathode rf gun at a repetition rate of 10 kHz. The 6 ps pulses will be accelerated to 250 MeV in a superconducting linac. The FEL consists of an exponential growth section followed by a tapered section. The amplifier input is a harmonic of a tunable visible laser generated either by nonlinear optical material or the nonlinearity of the FEL itself. The FEL output in 10(-4) bandwidth is 1 mJ per pulse, resulting in an average power of 10 W. The availability of radiation with these characteristics would open up new opportunities in photochemistry, biology and nonlinear optics, as discussed in a recent workshop held at BNL. RP BENZVI, I (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 12 TC 38 Z9 38 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 181 EP 186 DI 10.1016/0168-9002(91)90845-H PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500037 ER PT J AU CAPLAN, M KULKE, B BUBP, DG MCDERMOTT, D LUHMANN, N AF CAPLAN, M KULKE, B BUBP, DG MCDERMOTT, D LUHMANN, N TI A 250 GHZ CARM OSCILLATOR EXPERIMENT DRIVEN BY AN INDUCTION LINAC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB A 250 GHz cyclotron auto resonance maser (CARM) oscillator has been designed and constructed and will be tested using a 1 kA, 2 MeV electron beam produced by the induction linac at the Accelerator Research Center (ARC) facility of Lawrence Livermore National Laboratory (LLNL). The oscillator circuit was made to operate in the TE11 mode at 10 times cutoff using waveguide Bragg reflectors to create an external cavity Q of 8000. Theory predicts cavity fill times of less than 30 ns (pulse length) and efficiencies approaching 20% if sufficiently low transverse electron velocity spreads are maintained (2%). C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. RP CAPLAN, M (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 2 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 200 EP 203 DI 10.1016/0168-9002(91)90849-L PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500041 ER PT J AU FELDMAN, DW BENDER, SC CARLSTEN, BE EARLY, J FELDMAN, RB JOHNSON, WJD LUMPKIN, AH OSHEA, PG STEIN, WE SHEFFIELD, RL MCKENNA, K AF FELDMAN, DW BENDER, SC CARLSTEN, BE EARLY, J FELDMAN, RB JOHNSON, WJD LUMPKIN, AH OSHEA, PG STEIN, WE SHEFFIELD, RL MCKENNA, K TI PERFORMANCE OF THE LOS-ALAMOS HIBAF ACCELERATOR AT 17 MEV SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FACILITY AB The Los Alamos free electron laser (FEL) is being rebuilt with a photoelectric injector and 40 MeV beam energy for a lower emittance, brighter beam. Tests of the Los Alamos high-brightness accelerator FEL (HIBAF) system have been conducted including the photoinjector and first 17 MeV of acceleration. The photoinjector is designed to operate with a micropulse charge of 5 nC, peak current of 300 A, energy spread of 0.3%, and emittance of 50 pi mm mrad. Measurements of temporal and spatial beam characteristics have been made up to 10 nC per micropulse for both single micropulses and macropulses. The operational characteristics of the system components, e.g., drive laser and photoinjector are described. The results of beam and rf measurements are briefly presented and compared to simulation. The effects of nonaxially symmetric rf fields in the on-axis coupled accelerator structure were observed and are discussed. RP FELDMAN, DW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS-J579,LOS ALAMOS,NM 87545, USA. NR 4 TC 17 Z9 17 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 224 EP 227 DI 10.1016/0168-9002(91)90855-K PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500047 ER PT J AU KIM, KJ BERZ, M CHATTOPADHYAY, S EDIGHOFFER, J GOUGH, R KIM, C KUNG, AH STEIN, W XIE, M AF KIM, KJ BERZ, M CHATTOPADHYAY, S EDIGHOFFER, J GOUGH, R KIM, C KUNG, AH STEIN, W XIE, M TI DESIGN OVERVIEW OF A HIGHLY STABLE INFRARED FREE-ELECTRON LASER AT LBL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID WIGGLER AB An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV rf linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 mu-J per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 and 50-mu-m. In the design, we pay particular attention to the FEL stability issues and require that the fluctuation in electron beam energy and in timing be less than 0.05% and 0.1 ps, respectively. The FEL spectrum can then be stabilized to about 10(-3), or if grating is used, to 10(-4). We discuss various sources of fluctuation in the gun, the bunchers and the accelerator sections, as well as the feedback and feedforward schemes to reduce these fluctuations. The accelerator structure is chosen to be of the side-coupled, standing-wave type for easier control. The beam transport is made isochronous to avoid the coupling between the energy and the timing fluctuations. RP KIM, KJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. RI Kung, Andy/F-7909-2012 NR 13 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 233 EP 237 DI 10.1016/0168-9002(91)90858-N PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500050 ER PT J AU SHAY, HD JONG, RA RYNE, RD YU, SS SCHARLEMANN, ET AF SHAY, HD JONG, RA RYNE, RD YU, SS SCHARLEMANN, ET TI USE OF A FEL AS A BUNCHER FOR A TBA SCHEME SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON LASER; HIGH-GAIN; REGIME AB The CERN linear collider (CLIC) [W. Schnell, Proc. Workshop on Physics of Linear Colliders, Capri, 1988, eds. L. Palumbo, S. Tazzari and V.G. Vaccaro (1989) p. 345] is a two-beam-accelerator (TBA) scheme in which the driving beam consists of an intense 3 to 5 GeV electron beam bunched at 30 GHz. One possible way to produce this drive beam is to start with a low-energy (or order 10 MeV), high-current (about 5 kA) beam from an induction linac. In passing through a wiggler, this beam is bunched at 30 GHz into micropulses, each with about 10(12) electrons. To construct the format required for the CLIC drive beam, the bunched beam is subsequently chopped at 350 MHz. It is then accelerated to 3 to 5 GeV in an rf linac driven by conventional, low-frequency klystrons. Rf power is extracted at the bunch frequency of 30 GHz and fed into high-gradient structures to accelerate electron or positron beams to TeV energies. The drive beam is repeatedly reaccelerated in 350 MHz superconducting cavities. This study examines the design trade-offs of the proposed "front end" of the CLIC TBA, the linear induction accelerator and FEL. We examine the relevant figure of merit, the efficiency of bunching, as a function of beam energy, current, and emittance, and we consider the effects of wiggler errors, energy spread and slew, and beam misalignment. RP SHAY, HD (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 16 Z9 16 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 262 EP 267 DI 10.1016/0168-9002(91)90865-N PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500057 ER PT J AU CHAN, KCD SPALEK, G AF CHAN, KCD SPALEK, G TI CUMULATIVE BEAM BREAKUP OF THE GROUND-BASED FREE-ELECTRON LASER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB Strategies employed by the ground-based free electron laser system to maintain beam stability in its rf linac against cumulative beam breakup will be described. These strategies include a proper choice of the cavity shape and the use of staggered tuning. Simulations show that the growths of effective transverse emittance due to cumulative beam breakup can be limited to 10%. RP CHAN, KCD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 329 EP 332 DI 10.1016/0168-9002(91)90879-U PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500071 ER PT J AU DOWELL, DH LAUCKS, ML LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K ADAMSKI, J SHOFFSTALL, DR LUMPKIN, AH TOKAR, RL AF DOWELL, DH LAUCKS, ML LOWREY, AR BEMES, M CURRIE, A JOHNSON, P MCCRARY, K ADAMSKI, J SHOFFSTALL, DR LUMPKIN, AH TOKAR, RL TI IMPROVING ELECTRON-BEAM QUALITY OF THE BOEING FREE-ELECTRON LASER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB The successful operation of any free electron laser (FEL) is critically dependent upon electron beam quality. In a radiofrequency (rf) accelerator the micropulse or instantaneous beam emittance and peak current is established by the injector, however, it is important to maintain this beam's quality as it is accelerated and transported to the wiggler. In the past year, work has continued to enhance the electron beam of the Boeing FEL. The previous year's improvements in levelling the gun charge during the macropulse and rf power flatness were reported in the 1989 FEL conference. More recent work has concentrated upon the rf master oscillator and electron beam transport, which have lead to reduced macropulse energy spread, as well as decreased position and angle jitter. Also some electron beam diagnostics have been upgraded. The result has been lower macropulse emittance at the entrance to the wiggler. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP DOWELL, DH (reprint author), BOEING AEROSP & ELECTR,BOEING PHYS SCI & RES CTR,MAIL STOP 2T-50,POB 3999,SEATTLE,WA 98124, USA. NR 5 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 336 EP 341 DI 10.1016/0168-9002(91)90881-P PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500073 ER PT J AU GALLARDO, JC PALMER, RB AF GALLARDO, JC PALMER, RB TI EMITTANCE CORRECTION OF PHOTOCATHODE GUN SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB The standard emittance calculation removes linear correlations between transverse displacement r and the divergence r'. Higher order correlations remain and they are responsible for a substantial area in phase space which corresponds to the calculated emittance. Time-dependent correlations are identified and different procedures (transverse and longitudinal laser shaping, rf quadrupole) are proposed to remove them. The Brookhaven National Laboratory rf gun has been studied; however, in order to more clearly demonstrate the desired effects, the accelerating field and bunch length have been assumed to be more optimistic than the present operating values. This approach reduces the realizable emittance by a factor of 5 with respect to the value before the correction. RP GALLARDO, JC (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 10 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 345 EP 347 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500075 ER PT J AU JOHNSON, WJD ABDALLAH, CT AF JOHNSON, WJD ABDALLAH, CT TI ROBUST-CONTROL OF ACCELERATORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB The problem of controlling the variations in the rf power system can be effectively cast as an application of modern control theory. Two components of this theory are obtaining a model and a feedback structure. The model inaccuracies influence the choice of a particular controller structure. Because of the modelling uncertainty, one has to design either a variable, adaptive controller or a fixed, robust controller to achieve the desired objective. The adaptive control scheme usually results in very complex hardware; and, therefore, shall not be pursued in this research. In contrast, the robust control method leads to simpler hardware. However, robust control requires a more accurate mathematical model of the physical process than is required by adaptive control. Our research at the Los Alamos National Laboratory (LANL) and the University of New Mexico (UNM) has led to the development and implementation of a new robust rf power feedback system. In this article, we report on our research progress. In section 1, the robust control problem for the rf power system and the philosophy adopted for the beginning phase of our research is presented. In section 2, the results of our proof-of-principle experiments are presented. In section 3, we describe the actual controller configuration that is used in LANL FEL physics experiments. The novelty of our approach is that the control hardware is implemented directly in rf. without demodulating, compensating, and then remodulating. C1 UNIV NEW MEXICO,DEPT EECE,ALBUQUERQUE,NM 87131. RP JOHNSON, WJD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 2 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 364 EP 367 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500079 ER PT J AU LUMPKIN, AH CARLSTEN, BE FELDMAN, RB AF LUMPKIN, AH CARLSTEN, BE FELDMAN, RB TI 1ST MEASUREMENTS OF ELECTRON-BEAM TRANSIT TIMES AND MICROPULSE ELONGATION IN A PHOTOELECTRIC INJECTOR AT THE HIGH-BRIGHTNESS ACCELERATOR FEL (HIBAF) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB Key aspects of the dynamics of a photoelectric injector (PEI) on the Los Alamos high-brightness accelerator FEL (HIBAF) facility have been investigated using a synchroscan streak camera. By phase-locking the streak camera sweep to the reference 108.3 MHz rf signal, the variations of micropulse temporal elongations (30 to 80% over the drive-laser pulse length) and of transit times (25 ps for a 16-degrees phase change) were observed for the first time. These results were in good agreement with PARMELA simulations. RP LUMPKIN, AH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 3 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 374 EP 378 DI 10.1016/0168-9002(91)90890-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500082 ER PT J AU LUMPKIN, AH FELDMAN, RB CARLSTEN, BE FELDMAN, DW SHEFFIELD, RL STEIN, WE JOHNSON, WJ THODE, LE BENDER, SC BUSCH, GE AF LUMPKIN, AH FELDMAN, RB CARLSTEN, BE FELDMAN, DW SHEFFIELD, RL STEIN, WE JOHNSON, WJ THODE, LE BENDER, SC BUSCH, GE TI INITIAL OBSERVATIONS OF HIGH-CHARGE, LOW-EMITTANCE ELECTRON-BEAMS AT HIBAF SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID OPTICAL-TRANSITION RADIATION AB We report our initial measurements of bright (high-charge, low-emittance) electron beams generated at the Los Alamos high brightness accelerator FEL (HIBAF) facility. Normalized emittance values of less than 50-pi mm mrad for charges ranging from 0.7 to 8.7 nC were obtained for single micropulses at a y-waist and at an energy of 14.7 MeV. These measurements were part of the commissioning campaign on the HIBAF photoelectric injector. Macropulse measurements have also been performed and are compared with integrated numerical experiment (INEX) calculations. RP LUMPKIN, AH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 379 EP 385 DI 10.1016/0168-9002(91)90891-S PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500083 ER PT J AU TAKEDA, H DAVIS, K DELO, L AF TAKEDA, H DAVIS, K DELO, L TI BEAM QUALITY SIMULATION OF THE BOEING PHOTOINJECTOR ACCELERATOR FOR THE MCTD PROJECT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB We present a performance study of the photoinjector accelerator installed at Boeing Corp., Seattle, for the Modular Component Technology Development (MCTD) program. This 5 MeV injector operates at 433 MHz and is designed to produce a normalized emittance less than 100-pi mm mrad. This study was performed using the PARMELA simulation code. We study parametrically the dependence of the beam emittance on the magnetic fields produced by beam-guiding coils and by the gap coil located immediately after the first injector cavity. We also study the effect of phasing between cavities and the bunched electron beam. In addition to considering the parameters that determine the electron beam environment, we consider the space-charge effect on the bunched beam at higher charge. C1 BOEING CO,SEATTLE,WA 98124. RP TAKEDA, H (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS H829,LOS ALAMOS,NM 87545, USA. NR 2 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 396 EP 399 DI 10.1016/0168-9002(91)90894-V PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500086 ER PT J AU WALLACE, R CHAN, KCD AF WALLACE, R CHAN, KCD TI WAKEFIELD EFFECTS OF AUXILIARY BEAMLINE ELEMENTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB This article describes wakefields of a collection of auxiliary beamline elements. These elements include apertures used as emittance filters and energy-spread limiting slits. Some comments on the design of a shielding plate for reducing wakefields from beamline discontinuities are also given. RP WALLACE, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS H829,LOS ALAMOS,NM 87545, USA. NR 5 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 400 EP 405 DI 10.1016/0168-9002(91)90895-W PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500087 ER PT J AU GOLDSTEIN, JC WARREN, RW NEWNAM, BE AF GOLDSTEIN, JC WARREN, RW NEWNAM, BE TI DESIGN REQUIREMENTS AND CALCULATED PERFORMANCE OF AN XUV FEL OSCILLATOR OPERATING ON A HIGHER HARMONIC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON LASER AB We study, using numerical simulation methods, the design requirements for the electron beam, wiggler, and optical resonator of an extreme-ultraviolet (XUV, 100 greater-than-or-equal-to lambda greater-than-or-equal-to 10 nm) free electron laser oscillator operating on a higher harmonic. Our previous theoretical studies of an XUV FEL oscillator have assumed operation at the fundamental wavelength. Higher-harmonic operation is attractive because the energy of the electrons can be reduced, thus reducing the cost of the linac. A further reduction in beam energy is possible with the use of short-period wigglers: in the present work, we use the expected properties of pulsed-wire wigglers. Operation of a FEL oscillator on the third harmonic has been experimentally demonstrated at Stanford University and Los Alamos, and this mode of operation may also be both possible and desirable for an XUV device. RP GOLDSTEIN, JC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP X1,MS F645,LOS ALAMOS,NM 87545, USA. NR 12 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 449 EP 452 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500098 ER PT J AU KIM, KJ AF KIM, KJ TI THE EVOLUTION AND LIMITS OF SPECTRAL BANDWIDTH IN FREE-ELECTRON LASERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID COHERENCE AB We study the bandwidth in free electron lasers (FELs) under different circumstances; for weakly saturated FELs in storage rings, the bandwidth is given by the formula derived in the supermode theory, while it is given by the Fourier transform of the electron pulse length in the strongly saturated FELs in linacs. The limiting bandwidth for the case of a dc beam is given by a Schawlow-Townes formula, but the approach to the limit is very slow. RP UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 18 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 458 EP 462 DI 10.1016/0168-9002(91)90908-9 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500100 ER PT J AU SHARP, WM SESSLER, AM WHITTUM, DH WURTELE, JS AF SHARP, WM SESSLER, AM WHITTUM, DH WURTELE, JS TI SIMULATION OF A STANDING-WAVE FREE-ELECTRON LASER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB The standing-wave free electron laser (FEL) differs from a conventional linear-wiggler microwave FEL in using irises along the wiggler to form a series of standing-wave cavities and in reaccelerating the beam between cavities to maintain the average energy. The device has been proposed for use in a two-beam accelerator (TBA) because microwave power can be extracted more effectively than from a traveling-wave FEL. The standing-wave FEL is modeled in the continuum limit by a set of equations describing the coupling of a one-dimensional beam to a TE01 rectangular-waveguide mode. Analytic calculations and numerical simulations are used to determine the time variation of the reacceleration field and the prebunching required so that the final microwave energy is the same in all cavities. The microwave energy and phase are found to be insensitive to modest spreads in the beam energy and phase and to errors in the reacceleration field and the beam current, but the output phase appears sensitive to beam-energy errors and to timing jitter. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. RP SHARP, WM (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI wurtele, Jonathan/J-6278-2016 OI wurtele, Jonathan/0000-0001-8401-0297 NR 6 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 487 EP 491 DI 10.1016/0168-9002(91)90914-C PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500106 ER PT J AU WARREN, RW AF WARREN, RW TI LASING ON HIGHER HARMONICS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB Lasing at short wavelengths with an accelerator of modest energy can be achieved only with a wiggler of short period and high field, operating, perhaps, at a high harmonic of the fundamental frequency. We discuss the characteristics of wigglers of this kind, designed to lase with harmonic numbers as large as 50 or so, emphasizing their gain, efficiency, and sensitivity to emittance and energy spread. RP WARREN, RW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 5 TC 19 Z9 19 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 512 EP 515 DI 10.1016/0168-9002(91)90919-H PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500111 ER PT J AU YU, LH KRINSKY, S GLUCKSTERN, RL AF YU, LH KRINSKY, S GLUCKSTERN, RL TI UNIVERSAL SCALING FUNCTION FOR FEL GAIN SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON-LASER; AMPLIFIED SPONTANEOUS EMISSION; REGIME AB We have developed an analytic calculation of FEL gain in the exponential regime taking into account the finite emittance, energy spread, focusing and betatron oscillation of the electron beam, and the diffraction and guiding of the radiation. The gain is expressed in terms of a universal scaling function with only three independent parameters. Excellent agreement is found with results of numerical simulation. C1 UNIV MARYLAND,DEPT PHYS & ASTRON,COLLEGE PK,MD 20742. RP YU, LH (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 14 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 516 EP 519 DI 10.1016/0168-9002(91)90920-L PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500112 ER PT J AU ELLIOTT, CJ MCVEY, B SCHMITT, M AF ELLIOTT, CJ MCVEY, B SCHMITT, M TI SMALL-SIGNAL GAIN BASED ON ANALYTIC MODELS OF THIN INTENSE ELECTRON-BEAMS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FEL; OSCILLATOR AB We develop the free electron laser theory of the effective energy distribution and the small signal gain for a thin electron beam. The assumption of thinness allows us to treat various transverse locations and electron beam trajectory angles as introducing phase shifts that have the same effect as those introduced by a change in energy of the electron. These ideas extend previous work of Colson et al., Dattoli et al., Scharlemann, and others in five important ways. The first is the ability to treat electron beams with three different classes of matching or symmetry conditions: (i) electron beams with separate betatron matching in each plane. (ii) those with aspect ratio matching, and (iii) crossed matched beams. Manifestations of these symmetries include elliptical cross-sections and electron beams that have modulated spatial profiles. For these we derive analytical expressions for effective energy distributions. Second, two emittance parameters for the electron beam are shown to consolidate into a single parameter that describes most of the energy variation of the effective energy distributions. Thus, the effective energy distribution for a 1:4 ribbon electron beam is nearly equivalent to a distribution for a beam of circular cross-section. Third, these calculations extend to energy distributions, angular distributions, and spatial distributions that all follow Gaussian profiles. Fourth, this model incorporates the description of the incident Gaussian optical beam and the above electron beam dynamics into a single influence function kernel. Emittance, energy spread, diffraction, and gain may be interpreted as limiting the length over which the bunching contributions of the propagating electric fields downstream are important. Fifth, three-dimensional profiles of the optical fields are computed. This work is complementary to the recent work of Yu, Krinsky and Gluckstern in that ours always describes the transition from low gain to high gain for a thin beam and not necessarily the high-gain regime itself. Therefore in this work the parameters of the incident optical beam are included, whereas, their work is not concerned with these parameters. The resulting transverse dependence of the fields may be characterized by an optical beam radius. This optical beam width starts out large compared to the thin electron beam and then, in the example given, contracts to a size that becomes so small that the thin-beam assumption is violated. RP ELLIOTT, CJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 14 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 545 EP 550 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500119 ER PT J AU SCHMITT, MJ MCVEY, BD AF SCHMITT, MJ MCVEY, BD TI 3-DIMENSIONAL SIMULATIONS OF HARMONIC RADIATION AND HARMONIC LASING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON-LASER; UNDULATORS; SPECTRUM AB Characteristics of the harmonic emission from free electron lasers (FELs) are examined in the spontaneous, coherent-spontaneous and stimulated emission regimes. The radiation at both odd and even harmonic frequencies is treated for electron beams with finite emittance and energy spread. In the spontaneous emission regime, the transverse radiation patterns including the transverse frequency dependences, are given. How this expression is modified to include energy spread and emittance is described. In the coherent-spontaneous emission and stimulated emission (lasing) regimes, the interaction of the radiation fields with the electrons must be treated self-consistently. Here, a single-frequency distributed transverse source function for each electron is used in the harmonic version (HELEX) of the 3D code FELEX to model the harmonic radiation. This code has recently been modified to simultaneously model the fundamental and harmonic interactions for multiple-pass oscillator simulations. These modifications facilitate the examination of FELs under various operating conditions. When the FEL is lasing at the fundamental, the evolution of the harmonic fields can be examined. This evolution is unique in the sense that the electron beam (which is bunched by the fundamental optical field) radiates at the harmonic frequencies in the presence of the harmonic radiation circulating in the cavity. As a result, enhancements of the harmonic emission can be observed. Finally, harmonic lasing can occur in cases where there is sufficient gain to overcome cavity losses and lasing at the fundamental can be suppressed. The characteristics and efficiency of these interactions are explored. RP SCHMITT, MJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,POB 1663,MS F645,LOS ALAMOS,NM 87545, USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 571 EP 582 DI 10.1016/0168-9002(91)90932-G PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500124 ER PT J AU CARLSTEN, BE YOUNG, LM BROWMAN, MJ TAKEDA, H FELDMAN, DM OSHEA, PG LUMPKIN, AH AF CARLSTEN, BE YOUNG, LM BROWMAN, MJ TAKEDA, H FELDMAN, DM OSHEA, PG LUMPKIN, AH TI INEX SIMULATIONS OF EXPERIMENTALLY MEASURED ACCELERATOR PERFORMANCE AT THE LOS-ALAMOS HIBAF FACILITY SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID ELECTRON AB We present results of Integrated Numerical Experiment (INEX) simulations of the accelerator performance at the High Brightness Accelerator Free Electron Laser (HIBAF) facility at the Los Alamos National Laboratory. This 40 MeV machine was the first high-peak-current (I(p) > 300 A), low-emittance (epsilon-norm.90% < 40-pi mm mrad) accelerator designed with end-to-end code modeling, and close agreement between simulation and experimental measurements is needed to develop confidence in this procedure. In particular, accelerator parameters will be varied, and scalings of observable quantities will be compared. Comparisons will be made at the intermediate energy of 17 MeV. High-order rf modes and cavity asymmetries, as well as other detailed accelerator physics, will be included in the modeling. Beam behavior, such as emittance, energy spread, transverse distribution, and transport will be analyzed. RP CARLSTEN, BE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS-H825,LOS ALAMOS,NM 87545, USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 587 EP 592 DI 10.1016/0168-9002(91)90934-I PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500126 ER PT J AU GOLDSTEIN, JC TOKAR, RL MCVEY, BD ELLIOTT, CJ DOWELL, DH LAUCKS, ML LOWREY, AR AF GOLDSTEIN, JC TOKAR, RL MCVEY, BD ELLIOTT, CJ DOWELL, DH LAUCKS, ML LOWREY, AR TI INEX MODELING OF THE BOEING RING OPTICAL-RESONATOR FREE-ELECTRON LASER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID SIMULATIONS; OSCILLATOR AB We present new results from the integrated numerical model of the accelerator/beam transport system and ring optical resonator of the Boeing free electron laser experiment. Modifications of the electron-beam transport have been included in a previously developed PARMELA model and are shown to reduce dramatically emittance growth in the 180-degrees bend. The new numerically generated electron beam is used in the 3D FEL simulation code FELEX to calculate expected laser characteristics with the ring optical resonator and the 5 m untapered THUNDER wiggler. Performance sensitivity to optical cavity misalignments is studied. C1 BOEING AEROSP & ELECTR,SEATTLE,WA. RP GOLDSTEIN, JC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP X1,MS F645,LOS ALAMOS,NM 87545, USA. NR 9 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 622 EP 625 DI 10.1016/0168-9002(91)90940-R PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500132 ER PT J AU PIERINI, P FAWLEY, WM SHARP, WM AF PIERINI, P FAWLEY, WM SHARP, WM TI MULTIDIMENSIONAL SIMULATIONS OF THE ELFA SUPERRADIANT FREE-ELECTRON LASER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID HIGH-GAIN FEL; SLIPPAGE AB ELFA (electron laser facility for acceleration) is a high-gain, microwave (nu = 100 GHz) free electron laser (FEL) facility driven by an rf linac. ELFA will test the existence of the theoretically predicted regimes of strong and weak superradiance. Both regimes can be studied with the same FEL by changing the height of the interaction waveguide, which controls the radiation group velocity, and thus the relative slippage between electrons and photons. The operation of ELFA has been modeled using a modified version of the two-dimensional, time-dependent sideband code GINGER. The simulations take into account the time and space variations of the radiation field, as well as the space charge and transverse emittance of the electron beam. The sensitivity of the superradiant signal to variations of the beam emittance, energy and energy spread is examined. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP PIERINI, P (reprint author), IST NAZL FIS NUCL,VIA CELORIA 16,I-20133 MILAN,ITALY. RI Pierini, Paolo/J-3555-2012 OI Pierini, Paolo/0000-0002-3062-6181 NR 9 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 644 EP 648 DI 10.1016/0168-9002(91)90946-N PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500138 ER PT J AU SOUZA, R COLSON, WB WARREN, RW GOLDSTEIN, JC AF SOUZA, R COLSON, WB WARREN, RW GOLDSTEIN, JC TI EVALUATION OF COMPACT FELS OPERATING AT 0.4 MICRON WAVELENGTH SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID HIGHER HARMONICS; ELECTRON; SIMULATIONS AB Microwiggler operation for proposed compact free electron laser devices are simulated to explore the wider use of harmonics in order to reach optical wavelengths with moderate-to-low electron beam energy. We show the gain degradation due to energy spread and strong field saturation effects to demonstrate the advantages of using harmonics in order to reduce size and complexity of FEL systems. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP SOUZA, R (reprint author), USN,POSTGRAD SCH,DEPT PHYS,MONTEREY,CA 93943, USA. NR 7 TC 6 Z9 6 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 687 EP 690 DI 10.1016/0168-9002(91)90956-Q PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500148 ER PT J AU WARREN, RW PIOVELLA, N AF WARREN, RW PIOVELLA, N TI COMPOUND WIGGLER TO LASE ON A SELECTED HARMONIC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID FREE-ELECTRON LASER AB Lasing on the third harmonic of the fundamental FEL wavelength has recently been accomplished. Lasing on even higher harmonics appears to be possible and can offer advantages of various kinds. A serious problem is the necessity for suppressing lasing on unwanted harmonics and selecting only the desired one. We have devised a technique to select the desired harmonic that depends upon a modification to the design of the wiggler. We discuss the principles of this modification, the properties of modified wigglers, and give an example of a wiggler design that employs this technique. C1 UNIV MILAN,DIPARTMENTO FIS,I-20133 MILAN,ITALY. RP WARREN, RW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 9 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 696 EP 699 DI 10.1016/0168-9002(91)90958-S PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500150 ER PT J AU ELLIOTT, CJ MCVEY, BD QUIMBY, DC AF ELLIOTT, CJ MCVEY, BD QUIMBY, DC TI FIELD ERROR LOTTERY SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE ID ELECTRON AB The level of field errors in a free electron laser (FEL) is an important determinant of its performance. We have computed 3D performance of a large laser subsystem subjected to field errors of various types. These calculations have been guided by simple models such as SWOOP. The technique of choice is use of the FELEX free electron laser code that now possesses extensive engineering capabilities. Modeling includes the ability to establish tolerances of various types: fast and slow scale field bowing, field error level, beam position monitor error level, gap errors, defocusing errors, energy slew, displacement and pointing errors. Many effects of these errors on relative gain and relative power extraction are displayed and are the essential elements of determining an error budget. The random errors also depend on the particular random number seed used in the calculation. The simultaneous display of the performance versus error level of cases with multiple seeds illustrates the variations attributable to stochasticity of this model. All these errors are evaluated numerically for comprehensive engineering of the system. In particular, gap errors are found to place requirements beyond convenient mechanical tolerances of +/- 25-mu-m, and amelioration of these may occur by a procedure using direct measurement of the magnetic fields at assembly time. C1 SPECTRA TECHNOL INC,BELLEVUE,WA 98004. RP ELLIOTT, CJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,POB 1663,MS E531,LOS ALAMOS,NM 87545, USA. NR 4 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 JUL 1 PY 1991 VL 304 IS 1-3 BP 725 EP 731 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500157 ER PT J AU WARREN, RW AF WARREN, RW TI DESIGN CONSIDERATIONS FOR PULSED MICROWIGGLERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB Pulsed wigglers can generate planar wiggler fields near 5 T with periods of 3 mm or less, but many engineering problems are encountered in devising reliable systems that include the wiggler, the cooling system, and the power supply. We discuss these problems and our progress in solving them. RP WARREN, RW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 6 TC 19 Z9 19 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 765 EP 769 DI 10.1016/0168-9002(91)90972-S PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500164 ER PT J AU XIE, M KIM, KJ AF XIE, M KIM, KJ TI HOLE COUPLING RESONATOR FOR FREE-ELECTRON LASERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB The performance of two mirror resonators with holes for output coupling is studied for free electron laser application using a Fox-Li type code. The mode profiles inside and outside the cavity, the diffraction losses at the mirror edges and apertures, the amount of useful power coupled through the hole, etc., are calculated for the dominant mode for different hole and mirror dimensions. It is found that resonators in near concentric geometry can develop a mode degeneracy in certain cases, which should be avoided for the stability of the free electron laser gain and output. A resonator configuration for a free electron laser at Lawrence Berkeley Laboratory was found which can provide satisfactory performance over a wavelength range from 25 to 50-mu-m. The possibility of further increasing the tuning range by an adjustable intracavity aperture is discussed. RP XIE, M (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 17 TC 21 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 792 EP 796 DI 10.1016/0168-9002(91)90978-Y PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500170 ER PT J AU WARREN, R AF WARREN, R TI REPORT OF PANEL ON COMPACT FELS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON FREE ELECTRON LASER ( FEL 90 ) CY SEP 17-21, 1990 CL PARIS, FRANCE SP CEA, CNRS, DIRECT RECH & ETUDES TECH, FREE ELECTRON LASER CONF 88, MINIST RECH & TECHNOL FRANCE, SECRETARIAT GEN DEF NATL FRANCE, USN, OFF NAVAL RES, AEROSPATIALE AB This report is composed of two parts: first, a general discussion of compact FELs, to orient the reader and identify the critical issues; and second, an account of the presentations made before the panel by various contributors concerning their special compact devices or other special interests. RP WARREN, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUL 1 PY 1991 VL 304 IS 1-3 BP 828 EP 830 DI 10.1016/0168-9002(91)90986-Z PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FV595 UT WOS:A1991FV59500178 ER PT J AU ANDREANI, C MERLO, V RICCI, MA LEPOIRE, D AF ANDREANI, C MERLO, V RICCI, MA LEPOIRE, D TI ON THE MULTIPLE-SCATTERING CORRECTIONS IN AN INELASTIC NEUTRON-SCATTERING EXPERIMENT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article AB A phenomenological model for multiple scattering calculation in inelastic neutron scattering experiments is applied to the experimental data taken from a coherent scatterer (polycrystalline D2O) and compared with the results of a Monte Carlo evaluation on the same sample. C1 UNIV AQUILA,DIPARTIMENTO FIS,I-67010 COPPITO,ITALY. ARGONNE NATL LAB,IPNS,ARGONNE,IL 60439. RP ANDREANI, C (reprint author), UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,VIA E CARNEVALE,I-00173 ROME,ITALY. RI andreani, carla/E-9507-2012; OI merlo, vittorio/0000-0002-4858-3714 NR 8 TC 3 Z9 3 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 61 IS 1 BP 123 EP 126 DI 10.1016/0168-583X(91)95571-T PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ384 UT WOS:A1991FZ38400020 ER PT J AU ANTOLAK, AJ HANDY, BN MORSE, DH PONTAU, AE AF ANTOLAK, AJ HANDY, BN MORSE, DH PONTAU, AE TI ENERGY-LOSS AND STRAGGLING MEASUREMENTS OF IONS IN SOLID ABSORBERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID STOPPING POWER; EQUATION AB Measurements of the transmitted energy straggling and energy loss are made for 7 and 14 MeV hydrogen, 21 and 28 MeV lithium and 42 and 49 MeV carbon ion beams incident on C, Al, Ti, Ni, Ag, W and Au foils using a silicon surface barrier detector. Film thickness ranged from a few to hundreds of microns. The energy and Z2 dependence of the stopping power is investigated for each ion species. The experimental straggling widths are plotted as a function of the energy loss and compared to theoretical predictions. RP ANTOLAK, AJ (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94551, USA. NR 23 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 13 EP 17 DI 10.1016/0168-583X(91)95165-A PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900005 ER PT J AU GOKTEPE, OF AF GOKTEPE, OF TI A STATISTICAL COMPARISON OF MONTE-CARLO CODES TRIM AND EVOLVE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID RECOIL IMPLANTATION; TRANSPORT; TARGETS; SOLIDS AB The common variables in both TRIM and EVOLVE Monte Carlo codes were identified and parameterized by grouping them into specific ranges of interest and simple statistical tests were performed on them. In comparing the range distributions, the most significant differences between the two codes were found in the selection procedures and the ranges of the impact parameter and path length. RP GOKTEPE, OF (reprint author), US DOE,DIV HIGH ENERGY PHYS,ER-22 GTN,WASHINGTON,DC 20585, 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 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 28 EP 32 DI 10.1016/0168-583X(91)95168-D PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900008 ER PT J AU GOKTEPE, OF LAMBERT, JM VINCENZ, AM AF GOKTEPE, OF LAMBERT, JM VINCENZ, AM TI SPUTTERING YIELDS CALCULATIONS OF THIN GOLD-FILMS BOMBARDED WITH 175 KEV ARGON IONS - EFFECTS OF SURFACE BINDING AND DISPLACEMENT THRESHOLD ENERGIES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID PREFERENTIAL RECOIL IMPLANTATION; COMPUTER-SIMULATION; TRANSPORT; TARGETS; SOLIDS; MODEL AB EVOLVE simulation results of sputtering processes of Au films with 175 keV Ar ions are compared to available experimental results. Thicknesses of Au films are 23, 99 and 192 nm, which are small, comparable and large, respectively, compared to the range of Ar ions. As a result of dose-dependent analysis of Au films, a good agreement has been found if the displacement threshold energy of Au is assumed to be 12 eV. Reducing the surface binding energy of Au from 3.8 to 1.9 or even to 0.0 eV does not increase the sputtering yield as the elemental sputtering yield formula predicts. In fact, it has no significant effect at all on the sputtering yield if the elemental value, e.g. 36 eV, is used for the displacement threshold energy of Au. On the other hand, reducing the displacement threshold energy from 36 to 12 eV increases the sputtering yield by more than a factor of 2. The sputtering yield is expressed and discussed in terms of parametric relationships of the surface binding energy, displacement threshold energy, the film thickness and the fluence. C1 GEORGETOWN UNIV,DEPT PHYS,WASHINGTON,DC 20057. RP GOKTEPE, OF (reprint author), US DOE,DIV HIGH ENERGY PHYS,ER-22 GTN,WASHINGTON,DC 20585, USA. NR 21 TC 5 Z9 5 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 33 EP 36 DI 10.1016/0168-583X(91)95169-E PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900009 ER PT J AU WIEDERSICH, H AF WIEDERSICH, H TI THE EFFECT OF DEFECT CLUSTERS FORMED IN CASCADES ON THE SINK STRENGTH OF IRRADIATED MATERIALS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID ION-IRRADIATION; DAMAGE; SPECTRUM; METALS AB Defects produced by irradiation with energetic particles are often strongly spatially correlated. Energetic primary recoil atoms produce cascades with vacant lattice sites predominately in the central regions, and interstitial atoms at the periphery. A fraction of the defects produced forms clusters during cascade events. We examine the role of these clusters as defect sinks for high-dose irradiations at moderate temperatures. A population of vacancy and interstitial clusters evolves during irradiation which significantly contributes to the sink density. At temperatures at which thermal evaporation from vacancy clusters can be neglected, the cluster density is characteristic of the primary recoil spectrum, but is independent of temperature or dose rate. Contributions by migrating defects to irradiation-enhanced diffusion or to ion-beam mixing should be temperature and dose-rate independent. When thermal evaporation of vacancies from small defect clusters becomes competitive with absorption of excess interstitials, the cluster population becomes temperature and dose-rate dependent. RP ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 22 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X EI 1872-9584 J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 51 EP 56 DI 10.1016/0168-583X(91)95173-B PN 1 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900013 ER PT J AU YACOUT, AM LAM, NQ STUBBINS, JF AF YACOUT, AM LAM, NQ STUBBINS, JF TI DYNAMIC BEHAVIOR OF THE IMPLANT PROFILE DURING ION-IMPLANTATION AT ELEVATED-TEMPERATURES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The evolution of the implant distribution in time and space during elevated temperature ion implantation has been theoretically investigated using a comprehensive kinetic model. The implanted atoms were allowed to interact with the surface and with radiation-induced point defects. The synergistic effects of Gibbsian segregation, preferential sputtering, displacement mixing, radiation-enhanced diffusion, and radiation-induced segregation, as well as the influence of spatially nonuniform defect production were taken into account. The effects of the dynamical changes in the ion and damage distributions during implantation were also incorporated, by updating these distributions at high doses, using information obtained from TRIM calculations. Model calculations were performed for Al+ and Si+ implantation into Ni. C1 UNIV ILLINOIS,URBANA,IL 61801. RP YACOUT, AM (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 57 EP 59 DI 10.1016/0168-583X(91)95174-C PN 1 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900014 ER PT J AU SOBLE, CN AMEEN, MS ROU, SH WOOLCOTT, R AUCIELLO, O KINGON, AI KRAUSS, AR AF SOBLE, CN AMEEN, MS ROU, SH WOOLCOTT, R AUCIELLO, O KINGON, AI KRAUSS, AR TI DEVELOPMENT OF AN AUTOMATED DUAL ION-BEAM ASSISTED PROCESS FOR SUPERCONDUCTING OXIDE FILM DEPOSITION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID THIN-FILMS AB An automated dual ion beam sputter deposition system has been developed, in which individual targets of Y, Cu, and BaF2 are sequentially sputtered to produce Y-Ba-Cu-O films with controlled composition. The dwell time of the ion beam on each target is determined by a computer controlled feedback loop using the signal of a quartz crystal resonator. Each individual target is exposed to the ion beam at the same spatial location, which optimizes compositional and thickness homogeneity across the substrate surface. As deposited superconducting Y-Ba-Cu-O films have been successfully grown at temperatures in the range 700-720-degrees-C using either an oxygen ion beam or an ozone jet directed at the substrate. Oxygenation effects by the two sources on the film stoichiometry and microstructure are discussed. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. MICROELECTR CTR N CAROLINA,RES TRIANGLE PK,NC 27709. RP SOBLE, CN (reprint author), N CAROLINA STATE UNIV,RALEIGH,NC 27695, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 155 EP 158 DI 10.1016/0168-583X(91)95197-L PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900037 ER PT J AU RAI, AK BHATTACHARYA, RS YUST, CS DEVORE, CE AF RAI, AK BHATTACHARYA, RS YUST, CS DEVORE, CE TI THE MICROSTRUCTURE AND TRIBOLOGICAL PROPERTIES OF ION-BEAM ASSISTED CD-O AND TI-O COATINGS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID TEMPERATURES; DEPOSITION AB The microstructural and tribological properties of Cd-O and Ti-O films obtained by ion beam assisted deposition (IBAD) technique were studied. The IBAD process involved direct electron (e) beam evaporation of CdO and TiO2 while simultaneously bombarding with 500 eV O2+ ions. Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy (TEM) were used to determine the composition and microstructure of the films. A pin-on-disc tribotester was employed to determine the friction and wear characteristics of selected coatings. Ti-O films, with and without ion beams, were found to be amorphous while Cd-O films were polycrystalline under similar conditions. The oxygen-to-metal ratios in Ti-O and Cd-O films were approximately 2.2 and approximately 0.79, respectively. A reduction in friction and wear of M50 steel coated with ion beam assisted Ti-O film was observed. Ion beam assisted Cd-O film on M50 showed high friction at room temperature but lower friction at 400-degrees-C. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37830. RP RAI, AK (reprint author), UNIV ENERGY SYST INC,DAYTON,OH 45432, USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 280 EP 283 DI 10.1016/0168-583X(91)95223-Z PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900063 ER PT J AU ZUHR, RA HAYNES, TE GALLOWAY, MD TANAKA, S YAMADA, A YAMADA, I AF ZUHR, RA HAYNES, TE GALLOWAY, MD TANAKA, S YAMADA, A YAMADA, I TI FORMATION OF ALUMINUM FILMS ON SILICON BY ION-BEAM DEPOSITION - A COMPARISON WITH IONIZED CLUSTER BEAM DEPOSITION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID EPITAXIAL-GROWTH; SI(111); SI; GE AB The direct ion beam deposition (IBD) technique has been used to study the formation of oriented aluminum films on single crystal silicon substrates. In the IBD process, thin film growth is accomplished by decelerating a magnetically analyzed ion beam to low energies (10-200 eV) for direct deposition onto the substrate under UHV conditions. The aluminum-on-silicon system is one which has been studied extensively by ionized cluster beam (ICB) deposition. This technique has produced intriguing results for aluminum, with oriented crystalline films being formed at room temperature in spite of the 25% mismatch in lattice constant between aluminum and silicon. In this work, we have studied the formation of such films by IBD, with emphasis on the effects of ion energy, substrate temperature, and surface cleanliness. Oriented films have been grown on Si(111) at temperatures from 40 to 300-degrees-C and with ion energies of 30-120 eV per ion. Completed films were analyzed by ion scattering, X-ray diffraction, scanning-electron microscopy, and optical microscopy. Results achieved for thin films grown by IBD are comparable to those for similar grown by ICB deposition. C1 KYOTO UNIV,ION BEAM ENGN LAB,SAKYO KU,KYOTO 606,JAPAN. RP ZUHR, RA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Haynes, Tony/P-8932-2015 OI Haynes, Tony/0000-0003-2871-4745 NR 13 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 308 EP 311 DI 10.1016/0168-583X(91)95229-7 PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900069 ER PT J AU HOLLAND, OW WHITE, CW AF HOLLAND, OW WHITE, CW TI ION-INDUCED DAMAGE AND AMORPHIZATION IN SI SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID IMPLANTED SI; SILICON; CASCADE AB Ion-induced damage growth in high-energy, self-ion irradiated Si was studied using electron microscopy and Rutherford backscattering spectrometry. The results show that there is a marked variation in the rate of damage growth, as well as the damage morphology, along the path of the ion. Near the ion end-of-range (eor), damage increases monotonically with ion fluence until a buried amorphous layer is formed, while damage growth saturates at a low level in the region ahead. Damage growth remains saturated ahead of the eor until expansion of the buried amorphous layer encroaches into the region. The morphology of the damage in the saturated region is shown to consist predominantly of simple defect clusters such as the divacancy. A homogeneous nucleation and growth model, presented to account for damage saturation, is shown to also predict the dose-rate dependence of the saturation level. Mechanisms are identified which contribute to the unconstrained damage growth observed near the eor prior to amorphization, and subsequently at the interface of the buried amorphous layer. The effects of an imbalance in the generation rates of interstitials and vacancies on damage growth in the eor region are discussed. This imbalance is shown to arise either as a result of added atoms during implantation or spatial separation of the Frenkel defect pairs created during ion impact. A local, uniaxial strain field in the interfacial region of the amorphous layer is identified, and the possibility of its contribution to growth at that location is discussed. RP HOLLAND, OW (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 34 TC 86 Z9 86 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 353 EP 362 DI 10.1016/0168-583X(91)95238-9 PN 1 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900078 ER PT J AU BENCH, MW ROBERTSON, IM KIRK, MA AF BENCH, MW ROBERTSON, IM KIRK, MA TI TRANSMISSION ELECTRON-MICROSCOPY INVESTIGATION OF THE DAMAGE PRODUCED IN INDIVIDUAL DISPLACEMENT CASCADES IN GAAS AND GAP SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID ION-BOMBARDMENT; IMPLANTATION; INSITU AB The crystalline-to-amorphous transition induced by ion implantation has been investigated in GaAs and GaP using transmission electron microscopy, including experiments performed in situ and with, high-resolution TEM. Implantations have been made with Ar+, Kr+, Xe+, and Au+ ions (energy 50 or 80 kV) at 30 and 300 K. The high-resolution experiments have confirmed the amorphous nature of the damage produced in individual displacement cascades. The in situ experiments at 30 K have shown that amorphous zones are produced within isolated cascades with high probability. This probability decreases for room-temperature implantations of GaAs but remains the same for GaP. Annealing experiments in the 30-300 K range have shown that there is significant damage recovery below 300 K in GaAs but none in GaP. The experimental results are discussed in terms of the deposited energy density within the cascade, which has been determined through Monte Carlo simulations developed from TRIM. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP BENCH, MW (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801, USA. NR 13 TC 42 Z9 42 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 372 EP 376 DI 10.1016/0168-583X(91)95240-E PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900080 ER PT J AU GOLANSKI, A CHRISTIE, WH GALLOWAY, MD PARK, JL PENNYCOOK, SJ POKER, DB MOORE, JL HARMON, HE WHITE, CW AF GOLANSKI, A CHRISTIE, WH GALLOWAY, MD PARK, JL PENNYCOOK, SJ POKER, DB MOORE, JL HARMON, HE WHITE, CW TI ION-BEAM INDUCED DIFFUSION AND CRYSTALLIZATION IN HIGH-DOSE ER IMPLANTED SI SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID RARE-EARTH-METALS; SCHOTTKY-BARRIER; 111 SI; SILICIDES; SILICON; GROWTH; FILMS AB High doses (1 x 10(16)-1 x 10(17)/cm2) of 145 and 175 keV Er+ ions were implanted into single-crystal Si using implantation temperatures (T(i)) between room temperature and 520-degrees-C. Implanted samples were subsequently annealed using thermal annealing at 800-degrees-C under vacuum as well as 1 MeV As+ ion-beam-assisted annealing (IBAA) at 300-degrees-C. During Er+ implantation, we find evidence for ion beam induced mobility for T(i) as low as 300-degrees-C. A measurable redistribution of the implanted Er also occurs during the IBAA for Er doses greater than 5 x 10(16)/cm2. During Er implantation at T(i) > 300-degrees-C a polycrystalline ErSi2 phase is formed. For T(i) > 400-degrees-C the coherent precipitation of ErSi2 phase occurs within the crystalline Si matrix. During subsequent thermal annealing of samples implanted at T(i) > 400-degrees-C the Er distribution narrows due to Ostwald ripening, and preferential alignment occurs to form a discontinuous buried layer of a single-crystalline Er silicide. C1 CTR NATL ETUD TELECOMMUN,F-38240 MEYLAN,FRANCE. RP GOLANSKI, A (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 16 TC 14 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 444 EP 448 DI 10.1016/0168-583X(91)95256-D PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900096 ER PT J AU JENCIC, I BENCH, MW ROBERTSON, IM KIRK, MA PETERNELJ, J AF JENCIC, I BENCH, MW ROBERTSON, IM KIRK, MA PETERNELJ, J TI A COMPARISON OF THE RATES OF AMORPHIZATION IN THE ALXGA1-XAS/GAAS SYSTEM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The damage structure produced in GaAs and Al(x)Ga1-xAs (x = 0.85 and 0.20) by heavy-ion irradiations has been investigated by using the transmission electron microscope. The irradiations and the electron microscopy were performed at 30 and 300 K in situ using the HVEM accelerator facility at Argonne National Laboratory. The degree of amorphization at a particular ion dose was dependent on Al content, with the GaAs least resistant and the Al0.85Ga0.15As being the most resistant to amorphization. The reasons for these differences in resistance to amorphization will be considered in terms of cascade parameters and recrystallization rates. Preliminary results of simulation of amorphization, based on the semi-empirical randomization-and-relaxation method are also presented. C1 UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP JENCIC, I (reprint author), J STEFAN INST,JAMOVA 39,YU-61111 LJUBLJANA,YUGOSLAVIA. NR 14 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 458 EP 461 DI 10.1016/0168-583X(91)95259-G PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900099 ER PT J AU ALEXANDER, DE WAS, GS REHN, LE AF ALEXANDER, DE WAS, GS REHN, LE TI ION-INDUCED GRAIN-GROWTH IN MULTILAYER AND COEVAPORATED METAL ALLOY THIN-FILMS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID 3D METALS; ENTHALPIES; LIQUID AB Irradiation experiments were conducted on multilayer (ML) and coevaporated (CO) thin films in order to examine the role that the heat-of-mixing (DELTA-H(mix)) has in ion-induced grain growth. Room-temperature irradiations using 1.7 MeV Xe were performed in the High Voltage Electron Microscope at Argonne National Laboratory. The alloys studied (Pt-Ti, Pt-V, Pt-Ni, Au-Co and Ni-Al) spanned a large range of DELTA-H(mix) values. Comparison of grain growth rates between ML and CO films of a given alloy confirmed a heat of mixing effect. Differences in grain growth rates between ML and CO films scaled according to the sign and magnitude of DELTA-H(mix) of the system (with the exception of the Pt-V system). Substantial variations in growth rates among CO alloy films experiencing similar irradiation damage demonstrated that a purely collisional approach is inadequate for describing ion-induced grain growth and consideration must also be given to material-specific properties. Results from CO alloy films were consistent with a thermal spike model of ion-induced grain growth. The grain boundary mobility was observed to be proportional to the thermal spike-related parameter, F(D)2/DELTA-H(coh)3, where F(D) is the energy deposited in nuclear interactions and DELTA-H(coh) is the cohesive energy. C1 ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RP ALEXANDER, DE (reprint author), UNIV MICHIGAN, DEPT NUCL ENGN, ANN ARBOR, MI 48109 USA. NR 16 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 462 EP 466 DI 10.1016/0168-583X(91)95260-K PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900100 ER PT J AU KOIKE, J OKAMOTO, PR REHN, LE MESHII, M AF KOIKE, J OKAMOTO, PR REHN, LE MESHII, M TI CORRELATION BETWEEN THE ELASTIC SHEAR INSTABILITY MECHANISM AND EMPIRICAL CRITERIA FOR IRRADIATION-INDUCED AMORPHIZATION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID INTERMETALLIC COMPOUNDS; BRILLOUIN-SCATTERING; ION IRRADIATION; ALLOYS AB In an attempt to correlate the shear instability mechanism with empirical criteria for irradiation-induced amorphization, shear moduli of an A3B-type fcc crystal were calculated as a function of the chemical long range order parameter S using a Morse potential. The shear moduli were found to decrease with decreasing S. When the depth and the curvature of the A-B potential were changed while keeping the A-A and B-B potentials constant, the magnitude of the decrease in shear moduli is greater for deeper and narrower A-B potentials. The present results indicate that a shear instability should occur more readily in compounds with larger ordering energy and larger elastic moduli. These results agree with the reported empirical criteria for irradiation-induced amorphization, therefore providing further support for the shear instability mechanism for solid-state amorphization. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. RP KOIKE, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 10 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 471 EP 474 DI 10.1016/0168-583X(91)95262-C PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900102 ER PT J AU DODSON, BW AF DODSON, BW TI CHEMICAL EFFECTS IN SUB-KEV ION SOLID INTERACTIONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID EMBEDDED-ATOM-METHOD; SILICON STRUCTURAL ENERGIES; COMPUTER-SIMULATION; MOLECULAR-DYNAMICS; BEAM DEPOSITION; CASCADES; SURFACE; METALS; GROWTH; MODEL AB Computer simulation of low-energy ion-solid processes has greatly broadened in scope in recent years. In particular, realistic descriptions of the ion-solid and solid-solid interactions can now be utilized. The molecular dynamics technique, in which the equations of motion of the interacting atoms are numerically integrated, can now be used to characterize ion-solid interactions in a range of model material systems. Despite practical limitations of this procedure, a number of substantial results have appeared. The available results are examined to investigate the qualitative influence that chemical interactions have on low-energy ion-solid processes. RP DODSON, BW (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 28 TC 12 Z9 12 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 481 EP 486 DI 10.1016/0168-583X(91)95264-E PN 1 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900104 ER PT J AU GALUSKA, AA AF GALUSKA, AA TI MECHANISMS OF ADHESION ENHANCEMENT USING REACTIVE ION MIXING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID SI INTERMEDIATE LAYER; NI FILMS; KR-84+ IMPLANTATION; SI-28+ IMPLANTATION; GLASSY-CARBON; POLYESTER AB Reactive (Si-28+ and Al-27+) and nonreactive (Ar-40+ and Kr-84+) ion mixing was performed on Ni, Cu, and Ni/Si films on polymeric and ceramic substrates. Nonreactive ion mixing gave little or no adhesion enhancement despite substantial interfacial mixing and substrate hardening. Reactive ion mixing produced significant adhesion enhancements (2-45 x). These adhesion enhancements were attributed to the formation of ion-induced chemical complexes that chemically attach the films and substrates. These interfacial complexes are formed most readily by reactive ions that are thermodynamically reactive with both film and substrate species and that are capable of forming mixed chemical bonds. Reactive intermediate layers and nonreactive ion mixing can also produce interfacial complexes and adhesion enhancement, but care must be taken to avoid selective reaction and the formation of inert interfacial compounds. RP GALUSKA, AA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 12 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 487 EP 490 DI 10.1016/0168-583X(91)95265-F PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900105 ER PT J AU XIA, W HSU, SN HAN, CC PAPPERT, SA ZHU, B COZZOLINO, C YU, PKL LAU, SS POKER, DB WHITE, CW SCHWARZ, SA AF XIA, W HSU, SN HAN, CC PAPPERT, SA ZHU, B COZZOLINO, C YU, PKL LAU, SS POKER, DB WHITE, CW SCHWARZ, SA TI ION MIXING OF SEMICONDUCTOR SUPERLATTICES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID GAAS SUPER-LATTICE; STRAINED-LAYER SUPERLATTICES; QUANTUM-WELL STRUCTURES; ZN DIFFUSION; HETEROSTRUCTURE LASERS; IMPURITY DIFFUSION; IMPLANTATION; INTERDIFFUSION; DISORDER; SILICON AB Compositional disordering of III-V compound superlattice structures has received considerable attention recently due to its potential application for photonic devices. The conventional method to induce compositional disorder is to implant a moderate dose of impurity ions (approximately 10(15) cm-2) into the structure at room temperature, followed by a high-temperature annealing step (this process is referred to as IA here). Ion irradiation at room temperature alone does not cause any significant intermixing of layers. The subsequent high-temperature annealing step tends to restrict device processing flexibility. Ion mixing (IM) is capable of enhancing compositional disordering of layers at a rate which increases exponentially with the ion irradiation temperature. As a processing technique to planarize devices, ion mixing appears to be an attractive technology. In this work, we investigate compositional disordering in the AlGaAs/GaAs and the InGaAs/InP systems using ion mixing. We found that the ion mixing behavior of these two systems shows a thermally activated regime as well as an athermal regime, similar to that observed for metal-metal and metal-semiconductor systems. Ion mixing is observed to induce compositional disordering at significantly lower temperatures than that for the IA process. We have compared the two processes in terms of four parameters (1) irradiation temperature, (2) dose dependence, (3) annealing, and (4) electrically active ions. We found that the IM process is more efficient in utilizing the defects generated by ion irradiation to cause disordering. Both the physical mechanism of ion mixing and possible device implications will be discussed. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. BELLCORE,RED BANK,NJ 07701. RP XIA, W (reprint author), UNIV CALIF SAN DIEGO,DEPT ELECT & COMP ENGN,LA JOLLA,CA 92093, USA. NR 51 TC 14 Z9 14 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 491 EP 498 DI 10.1016/0168-583X(91)95266-G PN 1 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900106 ER PT J AU WOO, JJ FUNK, L BALDO, PM REHN, LE AF WOO, JJ FUNK, L BALDO, PM REHN, LE TI ELEVATED-TEMPERATURE IMPLANTATIONS OF AU INTO ZR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID DIFFUSION; IONS AB Polycrystalline Zr samples were implanted with 200 keV Au ions at several temperatures between 295 and 790 K to a dose of 5 x 10(15)/cm2. The implanted Au distributions were analyzed with RBS. A strong dependence of the Au distribution on implantation temperature was found for temperatures greater-than-or-equal-to 450 K, in good agreement with previous studies of interdiffusion and ion-beam mixing in Au/Zr multilayer specimens. For implantation temperatures between 500 and 600 K, a narrowing of the implanted distribution and an increase in the peak concentration were observed. At implantation temperatures greater-than-or-equal-to 650 K, a substantial fraction of the Au migrated toward the implanted surface. Systematic shifts of the peak in the implanted distribution were also found. The effects observed at the higher temperatures can be understood qualitatively in terms of radiation-induced segregation (RIS) and radiation-enhanced diffusion (RED) becoming dominant. The combined effects of sputtering, RIS, and RED substantially reduce the fraction of Au retained at elevated temperature. RP WOO, JJ (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, 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 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 537 EP 540 DI 10.1016/0168-583X(91)95274-H PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900114 ER PT J AU BROWN, DW MUNIR, ZA MUSKET, RG AF BROWN, DW MUNIR, ZA MUSKET, RG TI A PRECIPITATE COARSENING MECHANISM FOR BURIED LAYER FORMATION BY ION-IMPLANTATION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID COSI2 AB Buried monocrystalline aluminum layers have been formed in (1010BAR) beryllium targets by implanting 200 keV Al+ to a dose of 1.1 x 10(18) Al/cm2 and subsequently annealing the implanted material. Here we present a precipitate coarsening mechanism for aluminum layer formation based on the morphologies observed with electron microscopy. The evolution from a lamellar morphology in the as-implanted state to an aluminum layer with adjacent bands of aluminum precipitates in the annealed state is consistent with the occurrence of two different coarsening processes: one dependent on diffusion through beryllium which is responsible for the precipitate bands; and the second dependent on diffusion through aluminum and/or along Al-Be interfaces which is responsible for the layer. We conclude that formation of precipitate bands adjacent to a buried layer, elemental or compound, is evidence that the layer formed by a coarsening mechanism dominated by diffusion through the precipitated phase and/or along interphase boundaries. C1 UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 7 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 627 EP 631 DI 10.1016/0168-583X(91)95291-K PN 1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900131 ER PT J AU HUANG, JS AF HUANG, JS TI CARBIDE FORMATION IN NB AND TA IMPLANTED BY CARBON-IONS AT ROOM-TEMPERATURE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID SURFACE MECHANICAL-PROPERTIES AB Niobium and tantalum single crystals with <111> orientation were implanted with 200 keV C+ ions at room temperature to fluences of 7.6 x 10(17) and 1.5 x 10(18) carbon ions per cm2, respectively, which gave a calculated maximum carbon concentration of approximately 46 and 52 at.% in each material. The depth profiles of carbon were analyzed with Auger spectroscopy, and the phase formations were investigated with cross-sectional transmission electron microscopy. Face-centered-cubic nonstoichiometric NbC and TaC were formed in the implanted Nb and Ta, respectively; no Nb2C or Ta2C was formed. Based on the observed crystallographic relations between the fcc carbides and the bcc host lattices, and on the morphologies of the carbides, it is suggested that the fcc carbides are formed by a diffusionless martensitic transformation. RP HUANG, JS (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 11 TC 0 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 651 EP 654 DI 10.1016/0168-583X(91)95296-P PN 1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900136 ER PT J AU AVERBACK, RS DELARUBIA, TD HSIEH, HM BENEDEK, R AF AVERBACK, RS DELARUBIA, TD HSIEH, HM BENEDEK, R TI INTERACTIONS OF ENERGETIC PARTICLES AND CLUSTERS WITH SOLIDS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID EMBEDDED-ATOM METHOD; DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; COMPUTER-SIMULATION; COLLISION CASCADES; RADIATION-DAMAGE; PRIMARY STATE; METALS; BEAM; TRANSITION AB Ion beams are being applied for surface modifications of materials in a variety of different ways: ion implantation, ion beam mixing, sputtering, and particle or cluster beam assisted deposition. Fundamental to all of these processes is the deposition of a large amount of energy, generally some keV, in a localized area. This can lead to the production of defects, atomic mixing, disordering and in some cases, amorphization. Recent results of molecular dynamics computer simulations of energetic displacement cascades in Cu and Ni with energies up to 5 keV suggest that thermal spikes play an important role in these processes. Specifically, it will be shown that many aspects of defect production, atomic mixing and cascade collapse can be understood as a consequence of local melting of the cascade core. Included in this discussion will be the possible role of electron-phonon coupling in thermal spike dynamics. The interaction of energetic clusters of atoms with solid surfaces has also been studied by molecular dynamics simulations. This process is of interest because a large amount of energy can be deposited in a small region and possibly without creating point defects in the substrate or implanting cluster atoms. The simulations reveal that the dynamics of the collision process are strongly dependent on cluster size and energy. Different regimes where defect production, local melting and plastic flow dominate will be discussed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV CHEM,LIVERMORE,CA 94550. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP AVERBACK, RS (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801, USA. NR 43 TC 55 Z9 55 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 709 EP 717 DI 10.1016/0168-583X(91)95688-A PN 2 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000001 ER PT J AU KNAPP, JA FOLLSTAEDT, DM SORENSEN, NR POPE, LE AF KNAPP, JA FOLLSTAEDT, DM SORENSEN, NR POPE, LE TI AMORPHIZATION OF C-IMPLANTED FE(CR) ALLOYS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The amorphous phase formed by implanting C into Fe alloyed with Cr, which is a prototype for the amorphous phase formed by implanting C into stainless steels, is compared to that formed by implanting C and Ti into Fe and steels. The composition range of the phase has been examined; higher Cr and C concentrations are required than needed with Ti and C. The friction and wear benefits obtained by implanting stainless steels with C only do not persist for the long durations and high wear loads found with Ti and C. However, the amorphous Fe-Cr-C alloys exhibit good aqueous corrosion resistance. RP KNAPP, JA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 9 TC 10 Z9 10 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 742 EP 745 DI 10.1016/0168-583X(91)95694-9 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000007 ER PT J AU DEMAREE, JD WAS, GS SORENSEN, NR AF DEMAREE, JD WAS, GS SORENSEN, NR TI OXIDE FORMATION AND ANODIC POLARIZATION BEHAVIOR OF THIN-FILMS OF AMORPHOUS AND CRYSTALLINE FE-CR-P ALLOYS PREPARED BY ION-BEAM MIXING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB An experimental program has been conducted to determine the effect of phosphorus on the corrosion and passivation behavior of Fe-Cr-P alloys. Chemically homogeneous 60 nm films of Fe-10Cr-xP (x from 0 to 35 at.%) were prepared by multilayer evaporation followed by ion beam mixing with Kr+ ions. Films with a phosphorus content of at least 25 at.% were found to be entirely amorphous, while films with 15 at.% P consisted of both amorphous and bcc phases. Recrystallization of the amorphous phase was accomplished by heating the samples to 450-degrees-C in a purified argon flow furnace. Electrochemical polarization tests in an acid solution have shown the Fe-10Cr-xP films to be more corrosion resistant than Fe-10Cr, with the corrosion resistance increasing with the amount of P present. The corrosion resistance is not significantly affected when the amorphous films are recrystallized, indicating that the behavior is chemically controlled and not a result of the amorphous structure. When examined by XPS, the phosphorus appears to enhance passivation by encouraging Cr enrichment in the oxide and by incorporating in the oxide as phosphate. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP DEMAREE, JD (reprint author), UNIV MICHIGAN,ANN ARBOR,MI 48109, USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 757 EP 761 DI 10.1016/0168-583X(91)95697-C PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000010 ER PT J AU BHATTACHARYA, RS RAI, AK ERDEMIR, A AF BHATTACHARYA, RS RAI, AK ERDEMIR, A TI HIGH-ENERGY (MEV) ION-BEAM MODIFICATIONS OF SPUTTERED MOS2 COATINGS ON SAPPHIRE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID TRIBOLOGICAL PROPERTIES; FILMS AB The present article reports on the results of our investigations of high-energy (MeV) ion irradiation on the microstructural and tribological properties of dc magnetron sputtered MoS2 films. Films of thicknesses 500-7500 angstrom were deposited on NaCl, Si and sapphire substrates and subsequently ion irradiated by 2 MeV Ag+ ions at a dose of 5 X 10(15) cm-2. Scanning and transmission electron microscopy, Rutherford backscattering and X-ray diffraction techniques were utilized to study the structural, morphological and compositional changes of the film due to ion irradiation. The friction coefficient and sliding life were determined by pin-on-disc tests. Both as-deposited and ion-irradiated films were found to be amorphous having a stoichiometry of MoS1.8. A low friction coefficient in the range 0.03-0.04 was measured for both as-deposited and ion-irradiated films. However, the sliding life of ion-irradiated film was found to increase more than tenfold compared to as-deposited films indicating improved bonding at the interface. C1 ARGONNE NATL LAB,TRIBOL SECT,ARGONNE,IL 60439. RP BHATTACHARYA, RS (reprint author), UNIVERSAL ENERGY SYST INC,DAYTON,OH 45432, USA. NR 10 TC 10 Z9 12 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 788 EP 792 DI 10.1016/0168-583X(91)95705-I PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000018 ER PT J AU NASTASI, M HIRVONEN, JP ZOCCO, TG JERVIS, TR AF NASTASI, M HIRVONEN, JP ZOCCO, TG JERVIS, TR TI MICROSTRUCTURE AND TRIBOLOGY OF ION-MIXED FE/TI/C MULTILAYERS ON AISI-304 STAINLESS-STEEL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID MECHANICAL-PROPERTIES; FE-TI; FILMS; FRICTION; ALLOYS; METALS; WEAR AB A multilayered Fe/Ti/C structure consisting of eleven alternating sublayers, four Fe, four Ti and three C, was ion mixed on an AISI 304 stainless steel substrate with 400 keV Xe2+. Complete mixing was observed after an irradiation of 1 x 10(17) Xe/cm2 at 550-degrees-C. Electron diffraction revealed the formation of the compounds TiC and Fe3C and a small amount of an amorphous phase. Some samples were given a second irradiation with 5 x 10(15) Xe/cm2 at 0-degrees-C. The phases present following the second irradiation were TiC, alpha-Fe and an amorphous phase. Tribological and nanoindentation measurements revealed that both types of samples possessed similar hardness and friction properties. The ion mixed samples possessed an increased hardness and a decreased friction coefficient relative to untreated polished stainless-steel substrate. However, the wear life of the hot ion mixed sample was consistently longer than the wear life of the sample processed at both 550 and 0-degrees-C. These results are explained by differences in adhesive wear which result from differences in the chemical reactivity of the phases formed during ion beam processing. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP NASTASI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 13 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 806 EP 811 DI 10.1016/0168-583X(91)95709-M PN 2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000022 ER PT J AU WILLIAMS, JM GONZALES, A QUINTANA, J LEE, IS BUCHANAN, RA BURNS, FC CULBERTSON, RJ LEVY, M TREGLIO, JR AF WILLIAMS, JM GONZALES, A QUINTANA, J LEE, IS BUCHANAN, RA BURNS, FC CULBERTSON, RJ LEVY, M TREGLIO, JR TI ION-IMPLANTATION FOR CORROSION INHIBITION OF ALUMINUM-ALLOYS IN SALINE MEDIA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The effects of ion implantation treatments on corrosion of 2014 and 1100 aluminum in saline media were investigated. Implanted constituents were N, Si, Ti, and Cr. Techniques included salt spray testing, electrochemical studies, Rutherford backscattering spectrometry, and profilometry. The principal conclusion was that ion implantation of Cr is of potential practical benefit for corrosion inhibition of 2014 Al in salt environments. C1 AVSCOM,DERSO,CORPUS CHRISTI,TX. CORPUS CHRISTI ARMY DEPOT,CORPUS CHRISTI,TX. UNIV TENNESSEE,KNOXVILLE,TN 37996. USA,MAT TECHNOL LAB,WATERTOWN,MA 02172. ISM TECHNOL INC,SAN DIEGO,CA. RP WILLIAMS, JM (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 5 TC 18 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 845 EP 850 DI 10.1016/0168-583X(91)95717-R PN 2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000030 ER PT J AU VALLET, CE WHITE, CW AF VALLET, CE WHITE, CW TI APPLICATION OF ION-IMPLANTATION TO ELECTROCHEMICAL STUDIES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID TITANIUM ELECTRODES; CHLORINE EVOLUTION; SURFACE; RUO2; ELECTROCATALYSIS; SPECTROSCOPY; OXIDATION; CORROSION; ALUMINUM; MEDIA AB The application of ion implantation to electrochemical studies is illustrated with a study of electrocatalysis of the chlorine evolution reaction at RuO2, IrO2, TiO2 mixed oxide anodes in chloride solutions. Electrode/solution interfaces of well defined catalyst composition are generated in a reproducible manner by implantation of Ru (or Ir) into Ti followed by in situ oxidation of the near-surface titanium alloys. During the chlorine evolution reaction, the chlorine current is proportional to the surface concentration of the implanted impurity, and there is no surface accumulation of impurity during corrosion. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP VALLET, CE (reprint author), OAK RIDGE NATL LAB,DIV CHEM,POB 2008,OAK RIDGE,TN 37831, USA. NR 26 TC 2 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 855 EP 860 DI 10.1016/0168-583X(91)95719-T PN 2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000032 ER PT J AU KRAMER, KM TESMER, JR NASTASI, M AF KRAMER, KM TESMER, JR NASTASI, M TI OXIDATION STUDIES OF YTTRIUM IMPLANTED COPPER, MOLYBDENUM AND TANTALUM USING HIGH-ENERGY RESONANT HELIUM BACKSCATTERING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID HIGH-TEMPERATURE OXIDATION; RUTHERFORD-BACKSCATTERING AB The O-16(alpha,alpha)O-16 resonance at 8.8 MeV was used to determine the oxidation rates of Y implanted Cu, Mo and Ta. At back angles this resonance has a uniform cross section of almost-equal-to 25 times the Coulomb cross section over an energy range of almost-equal-to 0.6 MeV, allowing the surface oxidation of metals to be easily determined without the necessity of weighing the samples. Oxidations were made at 200, 400 and 500-degrees-C for Cu, Mo and Ta, respectively and for times ranging from 10 min to 10 h. At short times the oxidation is enhanced in the Y implanted materials as compared to unimplanted materials. However, as the oxidation times increase the oxidation rate in the implanted materials falls, and in the case of Cu and Ta the total amount of oxygen in the implanted samples eventually becomes lower than that of the unimplanted samples. In all cases Y implantation strongly effects the oxidation process. For Ta and Cu retardation of grain boundary oxidation occurs. For Mo, implantation produces a discrete oxide layer which grows in a layer-by-layer manner. These data indicate that the Y-Cu and the Y-Ta oxides are more passivating than their unimplanted counterparts. C1 MICHIGAN TECHNOL UNIV,HOUGHTON,MI 49931. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 11 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 865 EP 870 DI 10.1016/0168-583X(91)95721-O PN 2 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000034 ER PT J AU CARO, JA PEDRAZA, DF AF CARO, JA PEDRAZA, DF TI THE STABILITY OF IRRADIATION-INDUCED DEFECTS IN NIAL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID TRANSITION-METALS; AMORPHIZATION; DISORDER; ALLOYS; NI3AL AB Vacancies, interstitials and antisite defects are produced in intermetallic compounds by irradiation with energetic particles. The manner in which these defects evolve during irradiation may contribute to microstructural changes such as the generation of dislocations, dislocation loops, voids, phase transformations and amorphization. In this work, the embedded-atom potentials for nickel and aluminum developed by Foiles, Baskes and Daw were used to calculate the energy of formation of antisite defects, of vacancies, and of various possible interstitial configurations in the B2 NiAl compound. The crowdion in the [111] direction that incorporates an extra nickel atom is found to be the lowest-energy interstitial configuration. Using the same potentials, the distance for spontaneous recombination of Frenkel pairs is found to be third-nearest neighbor provided the chemical order is maintained. However, if the chemical order of the sites nearest to the interstitial is altered at a bcc cell adjacent to the cell occupied by the vacancy at the cell center, recombination is inhibited in several cases in which the Frenkel pair is found to be stable. The implications of these results for irradiation-induced amorphization are discussed. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP CARO, JA (reprint author), PAUL SCHERRER INST,CH-5232 VILLIGEN,SWITZERLAND. NR 19 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 880 EP 883 DI 10.1016/0168-583X(91)95724-R PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000037 ER PT J AU LAM, NQ TANG, S YACOUT, AM REHN, LE STUBBINS, JF AF LAM, NQ TANG, S YACOUT, AM REHN, LE STUBBINS, JF TI ION-BEAM MODIFICATIONS OF NEAR-SURFACE COMPOSITIONS IN TERNARY ALLOYS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID AG-AU-CU; ELEVATED-TEMPERATURES; SEGREGATION AB Changes in the surface and subsurface compositions of ternary alloys during elevated-temperature sputtering with inert-gas ions were investigated. Theoretically, a comprehensive kinetic model which includes all the basic processes, such as preferential sputtering, displacement mixing, Gibbsian segregation, radiation-enhanced diffusion and radiation-induced segregation, was developed. This phenomenological approach enabled to predict the effects of each individual process or of a combination of processes on the compositional modification in model alloys. Experimentally, measurements of compositional changes at the surface of a Ag-(40 at.% Au)-(20 at.% Cu) alloy during 3 keV Ne+ bombardment at various temperatures were made, using ion scattering spectroscopy. These measurements were interpreted on the basis of the results of theoretical modeling. C1 UNIV ILLINOIS,URBANA,IL 61801. RP LAM, NQ (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 8 TC 3 Z9 3 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 889 EP 892 DI 10.1016/0168-583X(91)95726-T PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000039 ER PT J AU BOURCIER, RJ FOLLSTAEDT, DM DUGGER, MT MYERS, SM AF BOURCIER, RJ FOLLSTAEDT, DM DUGGER, MT MYERS, SM TI MECHANICAL CHARACTERIZATION OF SEVERAL ION-IMPLANTED ALLOYS - NANOINDENTATION TESTING, WEAR TESTING AND FINITE-ELEMENT MODELING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The influence of ion implantation on the mechanical properties of metal alloys has been examined using a variety of experimental and numerical techniques. Ultralow load indentation testing and finite element modeling has been used for the aluminum/oxygen to extract fundamental mechanical properties. Aluminum implanted with 20 at.% O exhibits extraordinary strength, as high as 3300 MPa. The degree of strengthening expected for this Al(O) alloy on the basis of the observed microstructure of fine (1.5-3.5 nm) oxide precipitates was estimated using several micromechanical models, and the results agree with our experimental findings. Pin-on-disk tribological characterization of aluminum implanted with 10 at.% oxygen revealed that the ion-beam treatment reduced the average friction coefficient from greater than 1.0 (for pure Al) to approximately 0.25 (for Al(O)). Large-amplitude stick-slip oscillations, which occur within the first two cycles for pure aluminum, were postponed to 30-50 cycles for the ion-implanted material. Two stainless steels which have been amorphized by implantation, 304 implanted with C and 440C implanted with Ti + C, show measurable hardening with implantation, of the order of 40 and 15%, respectively. In addition, nanoindentation within pin-on-disk wear tracks on 440C reveals that the mechanical state of the extensively deformed implanted layer is apparently unchanged from its initial state. RP BOURCIER, RJ (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI bourcier, romain/D-6896-2015 OI bourcier, romain/0000-0002-6506-4019 NR 8 TC 19 Z9 19 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 905 EP 908 DI 10.1016/0168-583X(91)95730-2 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000043 ER PT J AU FOLLSTAEDT, DM MYERS, SM BOURCIER, RJ AF FOLLSTAEDT, DM MYERS, SM BOURCIER, RJ TI MICROSTRUCTURES OF CUBIC AL2O3 PRECIPITATES IN OXYGEN-IMPLANTED ALUMINUM SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The microstructure of Al ion-implanted at room temperature with 17 at.% O has been characterized with TEM. The alloy has extremely small (1.5-3.5 nm) oxide precipitates whose crystal structure is interpreted to be a disordered version of gamma-Al2O3 having a fcc lattice of O2- ions with Al3+ ions in random interstitial sites. The small sizes can account for the exceptionally high strength of as-implanted alloys: 2500-3300 MPa. Larger precipitates are found when the alloy is annealed 1/2 h at 550-degrees-C, which is consistent with its somewhat lower strength: 800-1600 MPa. RP FOLLSTAEDT, DM (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI bourcier, romain/D-6896-2015 OI bourcier, romain/0000-0002-6506-4019 NR 8 TC 14 Z9 14 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 909 EP 913 DI 10.1016/0168-583X(91)95731-R PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000044 ER PT J AU BIRTCHER, RC WANG, LM AF BIRTCHER, RC WANG, LM TI MICROSTRUCTURAL CHANGES INDUCED IN ZR3AL AND U3SI DURING IRRADIATION OF THE CRYSTALLINE STATE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID DISPLACEMENT CASCADES AB Microstructural changes produced in both Zr3Al and U3Si during irradiation with 1.5 MeV Kr ions have been followed by in situ transmission electron microcopy. When irradiated at sufficiently low temperatures, Zr3Al and U3Si become amorphous. During irradiation of the crystalline state at higher temperatures, the crystal structures are first disordered at doses comparable to those required for amorphization at low temperatures, and the pre-existing twin structure disappears from view in TEM. Continued irradiation of the disordered, large crystal grains results in the formation of new grains on the scale of 10 nm. During additional irradiation, the new grains increase in number and grow in size. Electron diffraction shows that new crystalline grains initially exhibit a preferred orientation to the original crystal lattice that decreases with continued irradiation until development of a powder-like diffraction pattern. The fine grain materials are resistant to amorphization during irradiation at lower temperatures and require up to a twenty-fold increase in the ion dose required for amorphization compared to that of initially unirradiated material. RP BIRTCHER, RC (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 13 TC 25 Z9 25 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 966 EP 969 DI 10.1016/0168-583X(91)95743-W PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000056 ER PT J AU HAYNES, TE HOLLAND, OW AF HAYNES, TE HOLLAND, OW TI DOSE-RATE EFFECTS ON DAMAGE FORMATION IN ION-IMPLANTED GALLIUM-ARSENIDE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID GAAS AB The residual damage in GaAs was measured by ion channeling following implantation of either 100 keV Si-30+ at temperatures of 300 or 77 K, or 360 keV Sn-120+ at 300 K. For room-temperature Si implants and fluences between 1 and 10 x 10(14) Si/cm2, the amount of damage created was strongly dependent upon the ion current density, which was varied between 0.05 and 12-mu-A/cm2. Two different stages of damage growth were identified by an abrupt increase in the damage growth rate as a function of fluence, and the threshold fluence for the onset of the second stage was found to be dependent on the dose rate. The dose rate effect on damage was substantially weaker for Sn-120+ implants and was negligible for Si implants at 77 K. The damage was found to be most sensitive to the average current density, demonstrating that the defects which are the precursors to the residual dose rate dependent damage have active lifetimes of at least 3 x 10(-4) s. The dose rate effect and its variation with ion mass and temperature are discussed in the context of homogeneous nucleation and growth of damage during ion irradiation. RP HAYNES, TE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. RI Haynes, Tony/P-8932-2015 OI Haynes, Tony/0000-0003-2871-4745 NR 10 TC 13 Z9 13 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1028 EP 1031 DI 10.1016/0168-583X(91)95757-5 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000070 ER PT J AU STEIN, HJ AF STEIN, HJ TI FORMATION AND STABILITY OF AS-H BONDS IN H-IMPLANTED GAAS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID HYDROGEN; PROTON; BEHAVIOR AB The chemical bonding and isochronal annealing of H implanted into GaAs at 80 K has been investigated by infrared absorption measurements. Based upon the frequency shift when deuterium is substituted for H, and an equivalent band formation in InAs, assignment of a new band at 2029 cm-1 is made to As-H centers. Bonding of H at interstitial As of an As-vacancy pair which anneals between 150 and 250 K is suggested as the structure for the defect. A previously reported absorption band at 1834 cm-1 assigned to Ga-H centers in H-implanted GaAs increases in intensity when H is released from As-H centers. RP STEIN, HJ (reprint author), SANDIA NATL LABS,DIV 1112,ALBUQUERQUE,NM 87185, USA. RI Schaff, William/B-5839-2009 NR 15 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1106 EP 1109 DI 10.1016/0168-583X(91)95775-9 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000088 ER PT J AU ALLEN, WR PEDRAZA, DF AF ALLEN, WR PEDRAZA, DF TI HIGH-ENERGY IRON-ION IMPLANTATION INTO SAPPHIRE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB Sapphire specimens of c-axis orientation were implanted at room temperature with iron ions at energies of 1.2 and of 2 MeV to various fluences up to 8 x 10(16) cm-2. The damage induced by the implantations was assessed by Rutherford backscattering spectrometry in random and channeling geometries. Dechanneling in both sublattices was observed to saturate for all implantation conditions. Disorder in the aluminum sublattice was found to increase with depth at a significantly slower rate than in the oxygen sublattice. In the oxygen sublattice, a relative yield chi of 0.80 +/- 0.11 was attained at a depth of 0.1-mu-m and remained constant up to the measured depth of 0.45-mu-m. In the aluminum sublattice, the disorder increased with depth and the dechanneling asymptotically approached chi = 0.70 +/- 0.04 at 0.45-mu-m. These results are discussed and compared with those for shallower Fe implantations obtained by other researchers. RP ALLEN, WR (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, 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 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1159 EP 1162 DI 10.1016/0168-583X(91)95785-C PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000098 ER PT J AU CHEN, Y ABRAHAM, MM PEDRAZA, DF AF CHEN, Y ABRAHAM, MM PEDRAZA, DF TI RADIATION-DAMAGE IN AL2O3 CRYSTALS IMPLANTED WITH 3.8 MEV FE2+ IONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID F+ CENTER; IRRADIATION AB Sapphire (alpha-Al2O3) crystals were implanted with 3.8 MeV Fe2+ ions to fluences of 0.5 x 10(16) and 2 x 10(16) cm-2. The sample face was perpendicular to the c-axis. The radiation damage produced by the implantation was investigated using optical and electron paramagnetic resonance (EPR) techniques. The former encompassed optical absorption and luminescence. The predominant defect detected optically was the oxygen vacancy with two electrons (F center), identified by an absorption peak at 6.2 eV (approximately 200 nm). The paramagnetic oxygen vacancy with one electron (F+ center) absorbs at 4.8 eV (approximately 260 nm) and was identified by EPR. Divacancies in various charge states were present in much lower concentrations and could not be unambiguously identified by optical absorption. Instead, they were detected by the highly sensitive luminescence measurements. Upon isochronal annealing between 500 and 1200 K, the concentration of the F center decreased monotonically. No evidence of the F+ center was found after annealing at 800 K. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. NR 12 TC 29 Z9 30 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1163 EP 1166 DI 10.1016/0168-583X(91)95786-D PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000099 ER PT J AU SKLAD, PS ROMANA, L MCHARGUE, CJ WHITE, CW MCCALLUM, JC AF SKLAD, PS ROMANA, L MCHARGUE, CJ WHITE, CW MCCALLUM, JC TI THE EFFECT OF POSTIMPLANTATION ANNEALING ON THE MICROSTRUCTURE OF AL2O3 IMPLANTED WITH IRON AT - 185-DEGREES-C SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB Analytical electron microscopy and Rutherford backscattering spectrometry have been used to investigate the effect of post-implantation annealing on the microstructure of Al2O3 implanted with iron at -185-degrees-C. By varying the implantation dose, annealing temperature, and annealing environment it has been possible to investigate the Fe2O3-Al2O3 and Fe-Al2O3 phase relationships. It was found that the as-implanted amorphous surface layer crystallizes according to a two-stage process. The amorphous layer first transforms to gamma-Al2O3 and then epitactical regrowth of alpha-Al2O3 follows. The redistribution of Fe during annealing is related to the Al2O3 phase present and is dependent on the annealing environment, O2 or 96% Ar-4% H2. The microstructure which develops during annealing at 1100-degrees-C in oxygen depends on the implantation dose (Fe concentration). Results show that as the dose increases the solubility limit of Fe2O3 in Al2O3 is exceeded and the excess Fe precipitates in the form of Fe2O3. During annealing at 1100-degrees-C in a reducing environment the majority of the Fe is driven towards the surface and precipitated as alpha-Fe. The observed phase transformations are in good agreement with the Fe2O3-Al2O3 phase diagram. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV WESTERN ONTARIO,DEPT PHYS,LONDON N6A 3K7,ONTARIO,CANADA. RP SKLAD, PS (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 7 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1187 EP 1194 DI 10.1016/0168-583X(91)95791-B PN 2 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000104 ER PT J AU BECKER, K YANG, L HAGLUND, RF MAGRUDER, RH WEEKS, RA ZUHR, RA AF BECKER, K YANG, L HAGLUND, RF MAGRUDER, RH WEEKS, RA ZUHR, RA TI LASER-INDUCED FLUORESCENCE AND NONLINEAR OPTICAL-PROPERTIES OF ION-IMPLANTED FUSED-SILICA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB We report absorption, fluorescence and nonlinear optical properties of fused silica implanted with Ti, Cu and Bi and doses of 1 x 10(15) to 6 x 10(16) ions/cm2 when irradiated with 532 nm laser light. The fluorescence spectrum is a broad band around 640 nm and shows little variation for all ion species. Absorption as a function of implanted dose shows a threshold for Ti between 1 x 10(16) and 6 x 10(16) ions/cm2. The nonlinear optical index is large, n2 > 10(-5) esu. All measured quantities show a strong dependence on the implanted ion dose. The source of the nonlinearity, whether electronic or thermal, remains to be more completely determined. C1 VANDERBILT UNIV,DEPT MAT SCI & ENGN,NASHVILLE,TN 37235. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP BECKER, K (reprint author), VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235, USA. NR 9 TC 32 Z9 32 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1304 EP 1307 DI 10.1016/0168-583X(91)95817-W PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000130 ER PT J AU MAGRUDER, RH ZUHR, RA WEEKS, RA AF MAGRUDER, RH ZUHR, RA WEEKS, RA TI DOSE-RATE DEPENDENCE OF THE OPTICAL-ABSORPTION OF CU IMPLANTED SILICA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID PARTICLE COMPOSITES AB High-purity silica (Spectrosil) samples were implanted with Cu at doses from 1.0 x 10(16) to 6.0 x 10(16) ions/cm2. Samples implanted to a dose of 6.0 x 10(16) ions/cm2 were implanted at dose rates of 7.5, 5, 2.6, and 0.7-mu-A/cm2. Some samples were implanted with smaller total doses at dose rates of 7.5 and 2.5-mu-A/cm2. Backscattering measurements determined the concentration of implanted ions as a function of dose and depth. The optical absorption, measured from 1.8 to 6.0 eV at room temperature, was observed to increase with increasing dose rate in samples implanted with a total dose greater-than-or-equal-to 3.0 x 10(16) ions/cm2. We attribute the increase in optical absorption at energies between 2 and 5 eV with dose in these samples to the formation of spherical copper colloids of various diameters. The peak at 2.2 eV that forms at dose levels greater-than-or-equal-to 3.0 x 10(16) was observed to increase nonlinearly with dose rate. We attribute this peak to the formation of prolate copper spheroids with an aspect ratio of approximately 2. We suggest that the dose rate dependence is due to localized heating which increases with increased dose rate. Samples implanted with doses < 3 x 10(16) ions/cm2 did not display this same strong dependence on dose rate. For these doses copper colloids are not a major source of absorption in the 2-5 eV range. In these samples we attribute the absorption to Cu+ and to intrinsic defects produced by radiation damage. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP MAGRUDER, RH (reprint author), VANDERBILT UNIV,DEPT MAT SCI & ENGN,BOX 1593-B,NASHVILLE,TN 37235, USA. NR 17 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1308 EP 1312 DI 10.1016/0168-583X(91)95818-X PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000131 ER PT J AU POLMAN, A JACOBSON, DC LIDGARD, A POATE, JM ARNOLD, GW AF POLMAN, A JACOBSON, DC LIDGARD, A POATE, JM ARNOLD, GW TI PHOTOLUMINESCENCE AND STRUCTURAL CHARACTERIZATION OF MEV ERBIUM-IMPLANTED SILICA GLASS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID LUMINESCENCE AB Suprasil glass (amorphous SiO2) has been implanted with 2.9 MeV Er ions at fluences of 3.4 x 10(15) and 3.4 x 10(16) ions/cm2. Photoluminescence spectra of implanted samples show a clear luminescent transition around lambda = 1.54-mu-m, corresponding to an intra-4f transition of Er3+. Flourescence decay times are in the range 1-8 ms, depending on implantation fluence and annealing treatment. UV absorption and IR reflection spectroscopy are employed to characterize beam-induced defects in the silica network. The results indicate that defects in the silica network play an important role in the energy transfer processes in the Er: silica system. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP POLMAN, A (reprint author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA. RI Polman, Albert/D-1490-2011 NR 15 TC 14 Z9 14 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1313 EP 1316 DI 10.1016/0168-583X(91)95819-Y PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000132 ER PT J AU HOU, PY BROWN, IG STRINGER, J AF HOU, PY BROWN, IG STRINGER, J TI STUDY OF THE EFFECT OF REACTIVE-ELEMENT ADDITION BY IMPLANTING METAL-IONS IN A PREFORMED OXIDE LAYER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID HIGH-TEMPERATURE; YTTRIUM; ALLOYS; SCALES; CR AB The influence of ion-implanted Y, Hf, Zr and Cr on the oxidation behavior of a Ni-25 wt.% Cr alloy at 1000-degrees-C has been investigated. The implantation dose was 5 X 10(16) ions/cm2. Two methods of implantation have been used. One was to implant ions directly into a clean alloy surface; the other was to implant into an approximately 0.6-mu-m thick Cr2O3 layer formed at 1000-degrees-C on the alloy. In neither case did the Cr implantation show any beneficial effects. Implantations of Y, Hf and Zr produced all the reactive element effects, i.e. reduction in oxidation rate, elimination of base-metal oxide formation and improvement in scale adhesion, only if the ions were initially implanted in the alloy. When the ions were implanted into a preformed oxide, the subsequent oxidation process was altered to the same degree as before, but the scale adhesion was not affected. Implications of these results to the mechanism of the reactive-element effect are discussed. C1 ELECT POWER RES INST,PALO ALTO,CA 94304. RP HOU, PY (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 10 TC 25 Z9 29 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1345 EP 1349 DI 10.1016/0168-583X(91)95827-Z PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000140 ER PT J AU MCHARGUE, CJ PEREZ, A MCCALLUM, JC AF MCHARGUE, CJ PEREZ, A MCCALLUM, JC TI THE CHEMICAL-STATE OF IRON IONS IMPLANTED INTO SILICON-CARBIDE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID MOSSBAUER AB Conversion electron Mossbauer spectroscopy (CEMS) was used to determine the local environment of Fe-57 implanted into single crystals of alpha-SiC at room temperature. Rutherford backscattering ion channeling measurements showed the specimens to be amorphous (random) for all fluences studied (1, 3, and 6 x 10(16) ions/cm2, 160 keV). The CEMS spectra were fit with a single component having a distribution of quadrupole split values, i.e., a distribution of electric field gradients. The results indicate a distribution of the implanted iron ions among several sites with slightly differing local environments. C1 UNIV LYON 1,DEPT PHYS MAT,F-69622 VILLEURBANNE,FRANCE. UNIV WESTERN ONTARIO,LONDON N6A 3K7,ONTARIO,CANADA. RP MCHARGUE, CJ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 18 TC 4 Z9 4 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1362 EP 1365 DI 10.1016/0168-583X(91)95831-W PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000144 ER PT J AU BHATTACHARYA, RS WU, RLC YUST, CS AF BHATTACHARYA, RS WU, RLC YUST, CS TI TRIBOLOGICAL PROPERTIES OF ION-BEAM DEPOSITED DIAMOND-LIKE CARBON-FILM ON SILICON-NITRIDE SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The present article reports on the physical characterization and tribological properties of diamond-like carbon (DLC) films deposited on structural Si3N4 substrates. The films were deposited by the direct ion beam deposition technique. The ion beam was produced by plasma discharge of pre-mixed methane and hydrogen gas in a Kaufman-type ion source. The deposited films were found to be amorphous and contained about 70% carbon and 30% hydrogen. The friction coefficient of an uncoated Si3N4 ball on a DLC coated Si3N4 disc starts at about 0.2, then decreases rapidly to 0.1-0.15 with increasing sliding distance. Increasing humidity results in a slight increase in friction coefficient, but a significant decrease in wear factor. The wear factor for the tests at almost-equal-to 60% rh (relative humidity) are about an order of magnitude smaller than the tests at 30% rh. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP BHATTACHARYA, RS (reprint author), UNIVERSAL ENERGY SYST INC,DAYTON,OH 45431, USA. NR 7 TC 12 Z9 12 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1383 EP 1386 DI 10.1016/0168-583X(91)95836-3 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000149 ER PT J AU BARBOUR, JC VENTURINI, EL GINLEY, DS AF BARBOUR, JC VENTURINI, EL GINLEY, DS TI IRRADIATION-INDUCED PINNING IN SINGLE-CRYSTAL AND THIN-FILM TL2CA2BA2CU3OY SUPERCONDUCTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID CU-O SYSTEM; CRITICAL CURRENTS AB Magnetization relaxation measurements were used to directly measure the effects of ion irradiation on magnetic flux pinning. The pinning potential U in a Tl2Ca2Ba2Cu3O(y) single crystal irradiated with 4.5 MeV protons, to a damage level of 4 x 10(-4) dpa, increased by almost-equal-to 25% at 25 K. In contrast, U for a highly oriented polycrystalline (pc) thin film irradiated with 300 keV He ions to a damage level of 2 x 10(-4) dpa increased by only 5% at 25 K (and less at higher temperatures). Enhancement of the magnetization critical current density J(cm) is determined as a function of temperature and damage in the single crystal and pc thin film. High-energy proton irradiation increased J(cm) in the single crystal by an order of magnitude at 25 K but had only a small effect on J(cm) in the pc thin film. RP BARBOUR, JC (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 15 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1395 EP 1398 DI 10.1016/0168-583X(91)95839-6 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000152 ER PT J AU BORDES, N BASU, SN ROLLETT, AD NASTASI, M AF BORDES, N BASU, SN ROLLETT, AD NASTASI, M TI PROPERTIES OF THIN-FILM YBA2CU3O7-X SUPERCONDUCTORS GROWN ON ION-IRRADIATED SRTIO3 SUBSTRATES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN AB The surfaces of [001] SrTiO3 substrates were modified by implantation of 400 keV Ne2+ ions at 77 K at doses of 5 x 10(14), 10(15) and 5 x 10(15) ions/cm2. Superconducting YBa2Cu3O7-x thin films were then deposited on these substrates by the electron beam co-evaporation and post-annealing process. The microstructure and properties of these films were characterized by various techniques and compared to a reference film that was grown on an unirradiated SrTiO3 substrate. The film on the substrate irradiated at the highest dose (5 x 10(16) ions/cm2) showed a deterioration of its properties as reflected by a loss in epitaxy, decrease in transition temperature and increase in transition width. However, films grown on the substrates irradiated at the lower doses showed improvements in the properties as compared to the reference film. The best film was obtained on the substrate irradiated at 10(15) ions/cm2. This film exhibited a significant improvement in epitaxy and an increase in the transition temperature as compared to the reference film. RP BORDES, N (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Rollett, Anthony/A-4096-2012 OI Rollett, Anthony/0000-0003-4445-2191 NR 9 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 JUL PY 1991 VL 59 BP 1399 EP 1403 DI 10.1016/0168-583X(91)95840-A PN 2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000153 ER PT J AU REHN, LE SHARMA, RP BALDO, PM FANG, Y AF REHN, LE SHARMA, RP BALDO, PM FANG, Y TI AN ION-CHANNELING STUDY OF IRRADIATION-INDUCED AMORPHIZATION OF YBA2CU3O7-X SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL CONF ON ION BEAM MODIFICATION OF MATERIALS ( IBMM 90 ) CY SEP 09-14, 1990 CL KNOXVILLE, TN ID SOLID-STATE AMORPHIZATION; NEUTRON-IRRADIATION; CURRENTS; DAMAGE AB We previously employed Brillouin scattering to demonstrate that the irradiation-induced crystalline-to-amorphous (c-a) transformation in several intermetallic compounds was preceded by a large (> 50%) decrease in shear elastic constant, indicative of an elastic instability. In situ electron diffraction revealed that the elastic softening was caused by static atom displacements. Here we report the results of an ion-channeling study designed to examine whether parallel changes occur during ion irradiation of single crystals of YBa2Cu3O7-x. The (static plus thermal) atomic displacements introduced during 1.5 MeV He-4 irradiation at a temperature of 100 K were determined from [001] axial channeling scans taken after several irradiation increments between 0 and 0.04 dpa. It was possible to obtain reliable channeling information at quite low doses, as low as 0.0004 dpa, because of the excellent minimum yields (chi-min < 3%) obtained from the high-quality single crystals. In agreement with the previous observations in intermetallic compounds, large atomic displacements, implying a drop in elastic modulus of greater-than-or-similar-to 90%, were found prior to the onset of amorphization. However, chi-min was found to be directly proportional to dose over a very broad range. The observed linear dependence on dose indicates that the irradiation-induced disorder develops continuously, and at the same rate from the very onset of the irradiation to nearly complete amorphization. RP REHN, LE (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP 1463 EP 1466 DI 10.1016/0168-583X(91)95853-6 PN 2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ030 UT WOS:A1991FZ03000166 ER PT J AU WITHROW, SP POKER, DB AF WITHROW, SP POKER, DB TI ION-BEAM MODIFICATION OF MATERIALS - PROCEEDINGS OF THE 7TH INTERNATIONAL-CONFERENCE ON ION-BEAM MODIFICATION OF MATERIALS KNOXVILLE, TN, USA, 9-14 SEPTEMBER 1990 .1. EDITORIAL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Editorial Material RP WITHROW, SP (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUL PY 1991 VL 59 BP R7 EP R7 DI 10.1016/0168-583X(91)95157-9 PN 1 PG 1 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FZ029 UT WOS:A1991FZ02900001 ER PT J AU KIKSTRA, SW GUO, Z VANDERLEUN, C ENDT, PM RAMAN, S WALKIEWICZ, TA STARNER, JW JURNEY, ET TOWNER, IS AF KIKSTRA, SW GUO, Z VANDERLEUN, C ENDT, PM RAMAN, S WALKIEWICZ, TA STARNER, JW JURNEY, ET TOWNER, IS TI SUPERALLOWED AL-26M(BETA++EC)MG-26 DECAY SO NUCLEAR PHYSICS A LA English DT Article DE MG-25(N,GAMMA), E = THERMAL; MEASURED E-GAMMA, I-GAMMA; MG-26 DEDUCED NEUTRON SEPARATION ENERGY; MG-25(P,GAMMA), E = 0.7-1.2 MEV; MEASURED EP, E-GAMMA; AL-26 DEDUCED RESONANCES, PROTON SEPARATION ENERGY; ISOMER (BETA++EC) DECAY Q, FT; ENRICHED TARGETS ID FERMI BETA-DECAY; CONSERVED-VECTOR-CURRENT; HALF-LIVES; RADIATIVE-CORRECTIONS; PROTON RESONANCES; STANDARD-MODEL; Q-VALUES; ENERGY; NUCLEI; SI-28 AB The reaction energies of Mg-25 (n, gamma) Mg-26 and Mg-25 (p, gamma) Al-m-(Al-26) have been measured as Q = 11093.24 6 and 6078.09 8 keV, respectively, which yields Q = 4232.81 10 keV for the Al-m-(Al-26)(beta+ + EC) Mg-26 decay energy. By combining it with the known Al-m-(Al-26) half-life and by applying electromagnetic corrections one obtains Ft = 3073.5 18 s for this superallowed 0+ --> 0+ decay, in good agreement with the value for the O-14 "standard" 0+ --> 0+ decay Ft = 3075.8 16 s, thus resolving a long-standing discrepancy. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. CHALK RIVER NUCL LABS,CHALK RIVER K0J 1J0,ONTARIO,CANADA. RP KIKSTRA, SW (reprint author), STATE UNIV UTRECHT,FYS LAB,POB 80000,3508 TA UTRECHT,NETHERLANDS. NR 62 TC 22 Z9 22 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 JUL 1 PY 1991 VL 529 IS 1 BP 39 EP 52 DI 10.1016/0375-9474(91)90784-4 PG 14 WC Physics, Nuclear SC Physics GA FX268 UT WOS:A1991FX26800004 ER PT J AU RANDRUP, J MEDEIROS, ED AF RANDRUP, J MEDEIROS, ED TI MODEL FOR STATISTICAL PROPERTIES OF NUCLEAR SYSTEMS AT FINITE TEMPERATURE SO NUCLEAR PHYSICS A LA English DT Article ID MATTER; HOT AB We develop a general model with which the statistical properties of nuclear systems can be addressed. Within a semi-classical treatment, using a new finite-range effective nucleon-nucleon interaction depending on both momentum and density, we derive expressions for the free energy as a functional of the specified spatial density distribution, at a given temperature. We explore a family of interactions that all yield the same reasonable properties of nuclear systems at zero temperature, but differ with regard to the effective mass of the nucleon. In order to make contact with other approaches, we calculate the equation of state for uniform isosymmetric matter and the associated phase diagram; the limiting temperature is 12-13 MeV, while the critical temperature is around 16 MeV. The response of uniform matter to density ripples is studied for a range of temperatures and densities and the calculated critical wave length is found to be sensitive to the new parameter governing the effective mass. C1 CTR BRASILEIRO PESQUISAS FIS,CONSELHO NACL DESENVOLVIMENTO CIENTIFICO & TECNOL,BR-22290 RIO DE JANEIRO,BRAZIL. RP RANDRUP, J (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 17 TC 20 Z9 20 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 JUL 1 PY 1991 VL 529 IS 1 BP 115 EP 140 DI 10.1016/0375-9474(91)90788-8 PG 26 WC Physics, Nuclear SC Physics GA FX268 UT WOS:A1991FX26800008 ER PT J AU BURGIO, GF CHOMAZ, P RANDRUP, J AF BURGIO, GF CHOMAZ, P RANDRUP, J TI FLUCTUATIONS IN NUCLEAR-DYNAMICS - FROM TRANSPORT-THEORY TO DYNAMIC SIMULATION SO NUCLEAR PHYSICS A LA English DT Article ID COLLISIONS AB Within the semiclassical Nordheim-type transport approach, we develop a method for treating arbitrary fluctuations in one-body dynamics, based on a direct simulation of the stochastic part of the collision integral. The method is illustrated for a uniform two-dimensional torus, for which the time evolution of the mean trajectory and the associated correlation function are calculated; the variance of the phase space occupancy follows closely the predictions of the corresponding Fokker-Planck equation and relaxes towards the appropriate quantum-statistical limit. The spontaneous breaking of the initial symmetries in phase-space makes it possible to employ the method to fluctuation-dominated physical processes, such as nuclear multifragmentation. RP BURGIO, GF (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 8 TC 73 Z9 73 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD JUL 1 PY 1991 VL 529 IS 1 BP 157 EP 189 DI 10.1016/0375-9474(91)90790-D PG 33 WC Physics, Nuclear SC Physics GA FX268 UT WOS:A1991FX26800010 ER PT J AU KRONFELD, AS WIESE, UJ AF KRONFELD, AS WIESE, UJ TI SU(N) GAUGE-THEORIES WITH C-PERIODIC BOUNDARY-CONDITIONS .1. TOPOLOGICAL-STRUCTURE SO NUCLEAR PHYSICS B LA English DT Article ID FINITE VOLUME; MASS; GLUEBALL; ENERGY; TORUS; FLUX AB C-periodic boundary conditions are introduced to SU(N) gauge theory on a torus. C-periodic fields are replaced by their charge conjugates when they are shifted over the boundary. As for periodic boundary conditions the most general C-periodic boundary condition includes twist. The topological structure with C-periodic boundary conditions is quite different from the periodic case. In the periodic case twist leads to the Z(N) 't Hooft flux sectors. In the C-periodic case with even N the symmetry of the flux sectors is reduced to Z2. For odd N the flux sectors are eliminated completely. Furthermore, the topological charge is an integer when N is odd, whereas it can be a half-integer when N is even. C1 FORSCHUNGSZENTRUM JULICH, HOCHSTLEISTUNGSRECHENZENTRUM HLRZ, THEORIE ELEMENTARTEILCHEN GRP, W-5170 JULICH 1, GERMANY. RP FERMI NATL ACCELERATOR LAB, THEORET PHYS GRP, POB 500, BATAVIA, IL 60510 USA. NR 11 TC 23 Z9 23 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD JUL 1 PY 1991 VL 357 IS 2-3 BP 521 EP 533 DI 10.1016/0550-3213(91)90479-H PG 13 WC Physics, Particles & Fields SC Physics GA FP867 UT WOS:A1991FP86700008 ER PT J AU GIVEON, A HALPERN, MB KIRITSIS, EB OBERS, NA AF GIVEON, A HALPERN, MB KIRITSIS, EB OBERS, NA TI EXACT C-FUNCTION AND C-THEOREM ON AFFINE-VIRASORO SPACE SO NUCLEAR PHYSICS B LA English DT Article ID 2D QUANTUM-GRAVITY; CURRENT-ALGEBRA; CENTRAL CHARGE; NICOLAI MAPS; MODELS; CONSTRUCTIONS; BOSONIZATION; FERMIONS; REPRESENTATIONS; DIMENSIONS AB An exact C-function, which is an action for the Virasoro master equation, is obtained on affine-Virasoro space. The solutions of the master equation are fixed points of an associated flow, which obeys a C-theorem. The closed sub-flow SO(n)diag is a flow on the space of graphs, and the associated Morse polynomials are known generating functions in graph theory. The general flow also implies a method for prediction of sporadic conformal deformations. We note the resemblance of this system to the expected form of an exact renormalization group equation. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, THEORET PHYS GRP, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. RI Kiritsis, Elias/F-3501-2011; Obers, Niels/D-1377-2014 OI Obers, Niels/0000-0003-4947-8526 NR 55 TC 24 Z9 24 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD JUL 1 PY 1991 VL 357 IS 2-3 BP 655 EP 690 DI 10.1016/0550-3213(91)90485-G PG 36 WC Physics, Particles & Fields SC Physics GA FP867 UT WOS:A1991FP86700014 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 7 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 JUL-SEP PY 1991 VL 32 IS 3 BP 402 EP 415 PG 14 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000010 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 JUL-SEP PY 1991 VL 32 IS 3 BP 424 EP 426 PG 3 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000012 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 JUL-SEP PY 1991 VL 32 IS 3 BP 427 EP 428 PG 2 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000013 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 8 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 JUL-SEP PY 1991 VL 32 IS 3 BP 429 EP 447 PG 19 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000014 ER PT J AU MUHLHEIM, MD AF MUHLHEIM, MD TI WORLD NUCLEAR PERFORMANCE SO NUCLEAR SAFETY LA English DT Article RP MUHLHEIM, MD (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 JUL-SEP PY 1991 VL 32 IS 3 BP 447 EP 453 PG 7 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000015 ER PT J AU MUHLHEIM, MD SILVER, EG AF MUHLHEIM, MD SILVER, EG TI GENERAL ADMINISTRATIVE ACTIVITIES SO NUCLEAR SAFETY LA English DT Article RP MUHLHEIM, MD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 8 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 JUL-SEP PY 1991 VL 32 IS 3 BP 454 EP 465 PG 12 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000016 ER PT J AU QUEENER, DS AF QUEENER, DS TI REPORTS, STANDARDS, AND SAFETY GUIDES SO NUCLEAR SAFETY LA English DT Article RP QUEENER, DS (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 JUL-SEP PY 1991 VL 32 IS 3 BP 465 EP 469 PG 5 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA HH390 UT WOS:A1991HH39000017 ER PT J AU MILLER, WF AF MILLER, WF TI AN ANALYSIS OF THE FINITE DIFFERENCED, EVEN-PARITY, DISCRETE ORDINATES EQUATIONS IN SLAB GEOMETRY SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID SYNTHETIC ACCELERATION METHODS; NUMERICAL TRANSPORT PROBLEMS; NEUTRON-TRANSPORT; ASYMPTOTIC SOLUTIONS; DIFFUSIVE REGIMES; OPTICALLY THICK AB Three spatial differencing schemes to be used with the even-parity, discrete ordinates, neutron transport equations are presented for the case of slab geometry and isotropic scattering and sources. These three schemes are analyzed in accordance with several desirable properties for spatial differencing schemes. The analysis indicates that cell-edge differencing of the even-parity equations yields a second-order, positive method that satisfies most diffusion limits and leads to an iteration that can be readily accelerated with an effective diffusion synthetic algorithm. The analyses indicate that this approach is quite promising and should be further developed. C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. RP MILLER, WF (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS A104,LOS ALAMOS,NM 87545, USA. NR 16 TC 9 Z9 9 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 JUL PY 1991 VL 108 IS 3 BP 247 EP 266 PG 20 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FU163 UT WOS:A1991FU16300004 ER PT J AU KATAYAMA, YB HOLTON, LK BUCK, GN HUTCHENS, JF CULVERHOUSE, MS AF KATAYAMA, YB HOLTON, LK BUCK, GN HUTCHENS, JF CULVERHOUSE, MS TI ADVANCED REMOTE DECONTAMINATION TECHNIQUES REDUCE COSTS AND RADIATION-DOSES SO NUCLEAR TECHNOLOGY LA English DT Article DE REMOTE DECONTAMINATION; ALARA; DECONTAMINATION AGENTS AB A highly contaminated cell in the Pacific Northwest Laboratory's (PNL) 324 Building Radiochemical Engineering Facilities was recently decontaminated using a series of remote and contact techniques. The approach used in decontaminating the cell was very successful: It resulted in an 87% lower radiation dose to workers and a cost saving of 39% compared with a hands-on procedure used in another cell 2 yr earlier. Eight cycles of remote decontamination, combining use of an alkaline cleaner foam spray and pressurized water rinse, preceded manned entry. Initial radiation readings in cell C, averaging 50 rad/h, were first reduced to < 200 mrad/h using remote techniques. Contact decontamination was then permissible using ultrahigh-pressure water at 270 MPa, further reducing the average radiation level in the cell to < 86 mrem/h. The radiation dose and the costs to achieve a 244-fold reduction in radiation contamination were 17.8 mrem/m2 and $1033/m2 of cell surface area. This work is part of a larger effort sponsored by the U.S. Department of Energy's Surplus Facilities Management Program to clean out six radioactive cells and to dismantle PNL's pilot-scale radioactive liquid-fed ceramic melter. In this program, numerous other advanced techniques are being developed and are proving valuable, particularly in lowering radiation doses. RP KATAYAMA, YB (reprint author), PACIFIC NW LAB, CTR WASTE TECHNOL, POB 999, RICHLAND, WA 99352 USA. NR 3 TC 1 Z9 2 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 JUL PY 1991 VL 95 IS 1 BP 44 EP 53 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA FQ883 UT WOS:A1991FQ88300004 ER PT J AU GRESHO, PM AF GRESHO, PM TI A SIMPLE QUESTION TO SIMPLE USERS SO NUMERICAL HEAT TRANSFER PART A-APPLICATIONS LA English DT Letter RP GRESHO, PM (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 0 TC 12 Z9 13 U1 0 U2 1 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 1040-7782 J9 NUMER HEAT TR A-APPL JI Numer. Heat Tranf. A-Appl. PD JUL-AUG PY 1991 VL 20 IS 1 BP 123 EP 123 PG 1 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA FX921 UT WOS:A1991FX92100008 ER PT J AU WOO, LK HAYS, JA JACOBSON, RA DAY, CL AF WOO, LK HAYS, JA JACOBSON, RA DAY, CL TI LOW-VALENT TITANIUM PORPHYRIN COMPLEXES - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE 1ST TITANIUM(II) PORPHYRIN COMPLEX, (ETA-2-DIPHENYLACETYLENE)TITANIUM OCTAETHYLPORPHYRIN SO ORGANOMETALLICS LA English DT Note ID RHODIUM OCTAETHYLPORPHYRIN; MOLYBDENUM(II) AB The anaerobic reduction of the dichlorotitanium(IV) porphyrins (OEP)TiCl2 and (TTP)TiCl2 (OEP = octaethylporphyrinato, TTP = meso-tetra-p-tolyl-porphyrinato) with LiAIH4 in the presence of diphenylacetylene in toluene produces the pi-alkyne Ti(II) adducts (OEP)Ti(eta-2-PhC = CPh) (1) and (TTP)Ti(eta-2-PhC = CPh) (2). The structure of 1 has been determined by single-crystal X-ray diffraction analysis. Complex 1 crystallizes in the centrosymmetric space group C2/c with a = 49.369 (7) angstrom, b = 13.734 (9) angstrom, c = 36.042 (5) angstrom, beta = 136.62 (1)-degrees, V = 16784 (9) angstrom 3, Z = 16, R = 0.061, and R(W) = 0.063. The asymmetric unit of 1 contains two molecules. Alkyne C-C distances and Ti-alkyne distances are 1.30 (1) (C27-C28), 2.016 (5) (Ti1-C27), 2.015 (5) (Ti1-C28), 1.30 (1) (C61-C62), 2.007 (7) (Ti2-C61), and 2.028 (7) angstrom (Ti2-C62). C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP WOO, LK (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 17 TC 39 Z9 39 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUL PY 1991 VL 10 IS 7 BP 2102 EP 2104 DI 10.1021/om00053a009 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA FW220 UT WOS:A1991FW22000009 ER PT J AU CHOI, MG ANGELICI, RJ AF CHOI, MG ANGELICI, RJ TI SULFUR-COORDINATED THIOPHENE AND DIBENZOTHIOPHENE IN CP'(CO)2RE(THIOPHENE) COMPLEXES SO ORGANOMETALLICS LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; SINGLE-CRYSTAL SURFACE; METAL-COMPLEXES; HYDRODESULFURIZATION CATALYSTS; BOND-CLEAVAGE; DESULFURIZATION; ADSORPTION; MODEL; TETRAHYDROTHIOPHENE; LIGAND AB A series of stable S-bound thiophene complexes Cp'(CO)2Re(Th), Cp' = C5H5 or C5Me5, Th = thiophene (T), 2-MeT, 3-MeT, 2,5-Me2T, Me4T, and dibenzothiophene (DBT), are prepared by the reaction of Cp'(CO)2Re(THF) with thiophenes. The first structural determination of a simple nonchelated S-coordinated thiophene complex Cp*(CO)2Re(T) is reported. Reactions of several of the Cp'(CO)2Re(Th) complexes [GRAPHICS] (Th = T, 2-MeT, and 3-MeT) with Fe2(CO)9 give thiophene-bridging dinuclear compounds Cp'(CO)2Re-(mu-2-eta-4(S)-Th)Fe(CO)3 thiophene is coordinated to the Re via the sulfur and to the Fe through the four carbons of the diene system. This reaction is the first to demonstrate that S coordination activates thiophene to undergo further reactions. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,GILMAN HALL,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 77 TC 56 Z9 56 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JUL PY 1991 VL 10 IS 7 BP 2436 EP 2442 DI 10.1021/om00053a056 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA FW220 UT WOS:A1991FW22000056 ER PT J AU ZHU, YM SUENAGA, M TAFTO, J AF ZHU, YM SUENAGA, M TAFTO, J TI MULTIPLE DIFFUSE-SCATTERING AND TWEED CONTRAST IN YBA2CU3O7-DELTA SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID NI-AL; MICROSTRUCTURES; MODULATIONS AB The diffuse electron scattering accompanying the tweed contrast in oxygen deficient and Fe, Co and Al doped YBa2Cu3O7-delta has been qualitatively corrected for double scattering effects. The kinematical diffuse scattering which results from this work suggests that shear or twinning displacement causes the tweed contrast, and may provide a useful basis for a better insight into the detail microstructure of these phases which are tetragonal on a macroscopic scale. RP ZHU, YM (reprint author), BROOKHAVEN NATL LAB,DEPT MAT SCI,UPTON,NY 11973, USA. NR 13 TC 26 Z9 26 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD JUL PY 1991 VL 64 IS 1 BP 29 EP 35 DI 10.1080/09500839108214663 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA FX362 UT WOS:A1991FX36200005 ER PT J AU HUNDLE, BS BEYER, P KLEINIG, H ENGLERT, G HEARST, JE AF HUNDLE, BS BEYER, P KLEINIG, H ENGLERT, G HEARST, JE TI CAROTENOIDS OF ERWINIA-HERBICOLA AND AN ESCHERICHIA-COLI HB101 STRAIN CARRYING THE ERWINIA-HERBICOLA CAROTENOID GENE-CLUSTER SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID CLONING; MONO; CIS AB Carotenoid pigments of Erwinia herbicola and a transformed strain of Escherichia coli carrying the carotenoid biosynthesis gene cluster of E. herbicola have been analyzed. Both organisms are capable of making essentially the same carotenoids, indicating that all of the genes required for the biosynthesis of the wild type E. herbicola carotenoids have been transformed intact into E. coli. The major products in both species of bacteria are beta-cryptoxanthin glucoside, zeaxanthin monoglucoside and zeaxanthin diglucoside. These compounds are the first example of secondary, non-allylic carotenoid glucosides. The absolute configuration 3R,3'R for zeaxanthin diglucoside was determined from its circular dichroism spectrum. Both species of bacteria also accumulate small amounts of hydrocarbon carotenes with similar cis/trans isomerization states. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720. F HOFFMANN LA ROCHE & CO LTD,CENT RES UNIT,CH-4002 BASEL,SWITZERLAND. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV FREIBURG,INST BIOL 2,W-7800 FREIBURG,GERMANY. FU NIEHS NIH HHS [2 T32 ES07075-11] NR 21 TC 31 Z9 32 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 JUL PY 1991 VL 54 IS 1 BP 89 EP 93 DI 10.1111/j.1751-1097.1991.tb01989.x PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GB386 UT WOS:A1991GB38600013 PM 1946693 ER PT J AU BARCLAY, WR JOHANSEN, JR TERRY, KL TOON, SP AF BARCLAY, WR JOHANSEN, JR TERRY, KL TOON, SP TI INFLUENCE OF IONIC PARAMETERS ON THE GROWTH AND DISTRIBUTION OF BOEKELOVIA-HOOGLANDII (CHROMOPHYTA) SO PHYCOLOGIA LA English DT Article ID FATTY-ACID; USA; ALGAE; LAKE; UTAH AB The small, flagellated monad Boekelovia hooglandii Nicolai et Baas Becking (Chromophyta) has not been reported in the literature since its initial discovery in a saline swimming pool in the Netherlands in 1935. This alga was recently observed in several temporary saline ponds in the central and western USA. The water where the alga was most abundant was characterized by a high concentration of sodium and bicarbonate ions, and a high monovalent:divalent (M:D) ionic ratio. Results of experiments to evaluate the growth and photosynthetic efficiency of B. hooglandii in several water types indicated that the alga exhibited its optimum growth rate and photosynthetic efficiency in water types with high M:D ratios. Growth rates tended to decline when divalent cation concentrations exceeded 20 mM. Despite exhibiting optimum growth in high M:D waters, the data also indicated that B. hooglandii could grow relatively well in lower M:D saline waters, such as seawater. Factors other than ionic composition appear to be limiting the distribution of this species in such waters. However, this alga appears to be much more abundant, particularly in temporary saline waters, than previously reported. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RI Johansen, Jeff/F-5616-2011 NR 25 TC 3 Z9 3 U1 0 U2 2 PU INT PHYCOLOGICAL SOC PI LAWRENCE PA NEW BUSINESS OFFICE, PO BOX 1897, LAWRENCE, KS 66044-8897 SN 0031-8884 J9 PHYCOLOGIA JI Phycologia PD JUL PY 1991 VL 30 IS 4 BP 355 EP 364 DI 10.2216/i0031-8884-30-4-355.1 PG 10 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA FZ306 UT WOS:A1991FZ30600005 ER PT J AU REMILLARD, SK ARENDT, PN ELLIOTT, NE AF REMILLARD, SK ARENDT, PN ELLIOTT, NE TI ELECTROPHORETIC DEPOSITION OF TL-BA-CA-CU-O AND BI2SR2CACU2OX THICK-FILMS SO PHYSICA C LA English DT Article ID SURFACE-RESISTANCE; SUPERCONDUCTORS; GROWTH AB Thick films of Bi-2212 and Tl-2212 superconductor were electrophoretically deposited onto Consil substrates. Tl series starting powder containing BaCuO2 impurity phase resulted in films with igher Tl content. X-ray diffraction showed that Bi-2212 films were well oriented only if melt textured. Melt textured Bi-2212 films were characterized in a TE011 resonant cavity at 17.46 GHz and compared to a magnetron sputtered Tl-2212 thick film. It was found that the surface resistance and surface reactance of the Bi-2212 were equally sensitive to external DC magnetic fields. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP REMILLARD, SK (reprint author), COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23185, USA. NR 21 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUL 1 PY 1991 VL 177 IS 4-6 BP 345 EP 350 DI 10.1016/0921-4534(91)90489-L PG 6 WC Physics, Applied SC Physics GA FX461 UT WOS:A1991FX46100011 ER PT J AU KIM, DH GRAY, KE KAMPWIRTH, RT SMITH, JC RICHESON, DS MARKS, TJ KANG, JH TALVACCHIO, J EDDY, M AF KIM, DH GRAY, KE KAMPWIRTH, RT SMITH, JC RICHESON, DS MARKS, TJ KANG, JH TALVACCHIO, J EDDY, M TI EFFECT OF CU-O LAYER SPACING ON THE MAGNETIC-FIELD INDUCED RESISTIVE BROADENING OF HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICA C LA English DT Article ID VORTEX-GLASS SUPERCONDUCTIVITY; LORENTZ-FORCE INDEPENDENCE; CRITICAL CURRENTS; RESISTANCE TAILS; TC; YBA2CU3O7-DELTA; CRYSTALS; PHASE; LINE AB For H parallel-to c-axis, the magnetic field induced broadening of the resistive transitions of high-T(c) superconductors (HTS) is shown to depend strongly on the Cu-O layer spacing. For the highly anisotropic HTS, we show experimental evidence that flux motion results from a thermally activated crossover from three dimensional (3D) vortex lines to 2D independent pancake-like vortices in the Cu-O layers, which is intrinsic to the material and occurs when k(B)T exceeds the Josephson coupling energy of these layers. At low temperatures, however, thermally activated conventional depinning (which can be sample dependent) or melting in the uncoupled 2D Cu-O layers is also required for flux motion. For YBa2Cu3O7, this dimensional crossover does not occur below H(c2,) presumably because the conducting Cu-O chains short-circuit the Josephson interlayer coupling, leading to better superconducting properties in a magnetic field. These results show that strong interlayer coupling is a key to finding good alternatives. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. NORTHWESTERN UNIV,SCI & TECHNOL CTR SUPERCONDUCT,EVANSTON,IL 60208. WESTINGHOUSE ELECT CORP,CTR SCI & TECHNOL,PITTSBURGH,PA 15235. SUPERCONDUCTING TECHNOL INC,SANTA BARBARA,CA 93111. RP KIM, DH (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 34 TC 285 Z9 285 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUL 1 PY 1991 VL 177 IS 4-6 BP 431 EP 437 DI 10.1016/0921-4534(91)90500-X PG 7 WC Physics, Applied SC Physics GA FX461 UT WOS:A1991FX46100022 ER PT J AU SCOFIELD, JH AF SCOFIELD, JH TI ANGULAR-DISTRIBUTION OF CASCADE X-RAYS FOLLOWING RADIATIVE RECOMBINATION FROM A BEAM SO PHYSICAL REVIEW A LA English DT Article ID POLARIZATION AB Calculations are carried out for the cross section for x-ray emission by n = 2 and 3 states resulting from the radiative recombination onto bare and hydrogenlike ions of titanium and iron from a beam of electrons with energies of several kilo electron volts. The calculation includes the contribution coming from direct recombination and cascades from higher-energy states. The density matrix of the magnetic sublevels is included in the calculation and results are given for the emission at 90-degrees to the direction of the incoming electron beam and its degree of linear polarization. The calculation is carried out relativistically assuming the incoming electrons move in a central potential. The bound states of the heliumlike ions are treated using a configuration-interaction code using basis states derived from a relativistic average-configuration Hartree-Fock code for the calculation of both the radiative-recombination and bound-state transition-matrix elements. RP SCOFIELD, JH (reprint author), LAWRENCE LIVERMORE NATL LAB,THEORET ATOM PHYS GRP,LIVERMORE,CA 94551, USA. NR 8 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 139 EP 143 DI 10.1103/PhysRevA.44.139 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400023 ER PT J AU CHEN, MH AF CHEN, MH TI AUGER TRANSITION RATES AND FLUORESCENCE YIELDS FOR THE DOUBLE-K-HOLE STATE SO PHYSICAL REVIEW A LA English DT Article ID BREIT INTERACTION; RAY; CONFIGURATIONS AB Auger and radiative transition rates and fluorescence yields for the double-K-hole state have been calculated for five elements with 10 less-than-or-equal-to Z less-than-or-equal-to 36 using the multiconfiguration Dirac-Fock method. The Auger and x-ray energies are found to shift to higher energies by 68-269 and 100-388 eV, respectively, due to the presence of the K-shell spectator vacancy. For low-Z elements, the transition rates per K hole for the double-K-hole state are much larger than the corresponding rates for the single-K-hole state. As Z increases to higher values, the differences in transition rates diminish. K-shell fluorescence yields for the double-K-hole state compared to the results for the single-K-hole state are found to increase by 33% at Z = 10 but by only 2.6% at Z = 36. RP CHEN, MH (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP PHYS,LIVERMORE,CA 94550, USA. NR 15 TC 50 Z9 50 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 JUL 1 PY 1991 VL 44 IS 1 BP 239 EP 242 DI 10.1103/PhysRevA.44.239 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400032 ER PT J AU HUTTON, R SCHNEIDER, D PRIOR, MH AF HUTTON, R SCHNEIDER, D PRIOR, MH TI ISOELECTRONIC STUDY OF DOUBLE-ELECTRON CAPTURE IN SLOW ION-ATOM COLLISIONS SO PHYSICAL REVIEW A LA English DT Article ID ANGULAR-MOMENTUM; CHARGED IONS; SPECTROSCOPY; HE; AR; TRANSITION; STATES; AUGER; KR AB We report studies of double-electron transfer in slow collisions (v almost-equal-to 0.2-0.4 a.u.) of the F-like (nine-electron) ions Si5+, Ar9+, Sc12+, Ti13+, Fe17+, and Cu20+ with He atoms. The transfer populates doubly excited states of the Na sequence (eleven electrons) of these elements that we study via the subsequent electron emission using high-resolution Auger spectroscopic techniques. Comparison is made to spectra that are formed by single-electron capture by Ne-like (ten-electron) ions in the 2p53s3P0,2 metastable levels. Non-Coulomb (Breit interaction) Auger decay of the Na-like metastable level 2p53s3p4D7/2 forms a prominent line in many of these spectra. C1 LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP PLASMA,LIVERMORE,CA 94550. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 30 TC 19 Z9 19 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 JUL 1 PY 1991 VL 44 IS 1 BP 243 EP 252 DI 10.1103/PhysRevA.44.243 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400033 ER PT J AU KIMURA, M LANE, NF AF KIMURA, M LANE, NF TI THEORETICAL-STUDY OF CHARGE-TRANSFER IN HE++H-2 COLLISIONS IN THE MILLI-ELECTRON-VOLT REGIME SO PHYSICAL REVIEW A LA English DT Article ID ENERGY SURFACES; MOLECULES; STATE; HE+; H-2 AB A theoretical investigation of charge transfer in He+ + H-2 collisions in the ultralow-energy regime (meV) has been conducted. Molecular states have been obtained by using the multiconfiguration self-consistent-field method. The reaction rate constants have been calculated for dissociative and radiative charge-transfer processes. Agreement with the recent measurements of Schauer et al. [J. Chem. Phys. 91, 4593 (1989)] is satisfactory. The present study provides a theoretical rationale for the experimental findings by interpreting the detailed collision dynamics. C1 RICE UNIV,DEPT PHYS,HOUSTON,TX 77251. RICE UNIV,RICE QUANTUM INST,HOUSTON,TX 77251. RP KIMURA, M (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 18 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 259 EP 263 DI 10.1103/PhysRevA.44.259 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400035 ER PT J AU OREG, J GOLDSTEIN, WH BARSHALOM, A KLAPISCH, M AF OREG, J GOLDSTEIN, WH BARSHALOM, A KLAPISCH, M TI SUM-RULES FOR COLLISIONAL PROCESSES SO PHYSICAL REVIEW A LA English DT Article ID IONS; IONIZATION; EXCITATION; SPECTRA; PLASMAS; MODEL; LINE; GAIN AB We derive level-to-configuration sum rules for dielectronic capture and for collisional excitation and ionization. These sum rules give the total transition rate from a detailed atomic level to an atomic configuration. For each process, we show that it is possible to factor out the dependence on continuum-electron wave functions. The remaining explicit level dependence of each rate is then obtained from the matrix element of an effective operator acting on the bound orbitals only. In a large class of cases, the effective operator reduces to a one-electron monopole whose matrix element is proportional to the statistical weight of the level. We show that even in these cases, nonstatistical level dependence enters through the dependence of radial integrals on continuum orbitals. For each process, explicit analytic expressions for the level-to-configuration sum rules are given for all possible cases. Together with the well-known J-file sum rule for radiative rates [E. U. Condon and G. H. Shortley, The Theory of Atomic Spectra (University Press, Cambridge, 1935)], the sum rules offer a systematic and efficient procedure for collapsing high-multiplicity configurations into ''effective'' levels for the purpose of modeling the population kinetics of ionized heavy atoms in plasma. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. RP OREG, J (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 27 TC 4 Z9 4 U1 2 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 JUL 1 PY 1991 VL 44 IS 1 BP 310 EP 323 DI 10.1103/PhysRevA.44.310 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400041 ER PT J AU RHOADESBROWN, MJ WENESER, J AF RHOADESBROWN, MJ WENESER, J TI HIGHER-ORDER EFFECTS ON PAIR CREATION BY RELATIVISTIC HEAVY-ION BEAMS SO PHYSICAL REVIEW A LA English DT Article ID COLLISIONS AB Assuming the approximation of pair independence, the number of pairs produced by a classical, imperturbable electromagnetic source is shown to be described by a Poisson distribution. The perturbational calculation of pairs by colliding heavy-ion beams is treated by straightforward summation of the diagrammatically defined series. The extended calculation, in which all orders of interaction between colliding ions and the electron-positron system are included, is also demonstrated to result in a Poisson-number distribution. Applications to current heavy-ion colliders are made. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP RHOADESBROWN, MJ (reprint author), BROOKHAVEN NATL LAB,RELAT HEAVY ION COLLIDER PROJECT,UPTON,NY 11973, USA. NR 12 TC 46 Z9 46 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 330 EP 336 DI 10.1103/PhysRevA.44.330 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400043 ER PT J AU SORENSEN, SL SCHAPHORST, SJ WHITFIELD, SB CRASEMANN, B CARR, R AF SORENSEN, SL SCHAPHORST, SJ WHITFIELD, SB CRASEMANN, B CARR, R TI L-SHELL COSTER-KRONIG TRANSITION-PROBABILITIES IN NI, CU, AND MO MEASURED WITH SYNCHROTRON RADIATION SO PHYSICAL REVIEW A LA English DT Article ID L-SUBSHELL FLUORESCENCE; X-RAY-FLUORESCENCE; HEAVY-ELEMENTS; PHOTOIONIZATION METHOD; MULTIPLE IONIZATION; VACANCY STATES; AUGER-SPECTRA; YIELDS; EMISSION; ARGON AB A recent technique, based on differential subshell ionization by tuned synchrotron radiation, has been applied to measurements of L-subshell Coster-Kronig yields of Ni, Cu, and Mo from L2 and L3 Auger spectra. Results for Ni are f23 = 0.6 + 0.2, f12 = 0.4 + 0.2, and f13 = 0.5 + 0.2; for Cu, f23 = 0.8 + 0.1, f12 = 0.44 + 0.06, and f13 = 0.3 + 0.2; for Mo, f23 = 0.15 + 0.02, f12 = 0.15 + 0.02, and f13 = 0.61 + 0.06. Measured transition probabilities are compared with previously available information. The results are generally consistent with the body of theoretical and experimental data. For Ni and Cu, the present measurements of f23 confirm that the L2-L3M4,5 Coster-Kronig channel is accessible in the metals, even though it is energetically cut off in free atoms. Further improvements in synchrotron-radiation sources are likely to make it possible to throw light on several critical questions by means of the present method. C1 STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94309. RP SORENSEN, SL (reprint author), UNIV OREGON,DEPT PHYS,EUGENE,OR 97403, USA. OI Sorensen, Stacey/0000-0002-1706-0232 NR 80 TC 38 Z9 38 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 JUL 1 PY 1991 VL 44 IS 1 BP 350 EP 357 DI 10.1103/PhysRevA.44.350 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400046 ER PT J AU BEIERSDORFER, P CHEN, MH MARRS, RE SCHNEIDER, MB WALLING, RS AF BEIERSDORFER, P CHEN, MH MARRS, RE SCHNEIDER, MB WALLING, RS TI DIELECTRONIC SATELLITE SPECTRUM OF HELIUM-LIKE VANADIUM SO PHYSICAL REVIEW A LA English DT Article ID HE-LIKE IONS; RESONANCE LINE; RECOMBINATION; SPECTROMETER; TRANSITIONS; TEMPERATURE; EXCITATION; TITANIUM; NICKEL; SHIFTS AB K x-ray spectra of heliumlike vanadium and associated dielectronic satellite emission from lithiumlike, berylliumlike, and boronlike vanadium have been observed with a high-resolution crystal spectrometer from the Lawrence Livermore electron-beam ion trap. Measurements include dielectronic satellite spectra from the KLL, KLM, KLN, KLO, and KLP resonance. Many transitions are identified that are unresolved in plasma observations, and transition energies are measured with high accuracy. Comparisons of calculated and observed intensities of selected transitions show few differences. RP BEIERSDORFER, P (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP PHYS,LIVERMORE,CA 94550, USA. NR 41 TC 24 Z9 25 U1 2 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 JUL 1 PY 1991 VL 44 IS 1 BP 396 EP 409 DI 10.1103/PhysRevA.44.396 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400053 ER PT J AU ALLENDORF, SW SZOKE, A AF ALLENDORF, SW SZOKE, A TI HIGH-INTENSITY MULTIPHOTON IONIZATION OF H-2 SO PHYSICAL REVIEW A LA English DT Article ID ABOVE-THRESHOLD IONIZATION; MULTIPLE-HARMONIC CONVERSION; SUBPICOSECOND LASER-PULSES; DISSOCIATIVE IONIZATION; 1064-NM RADIATION; EXCITED-STATE; NOBLE-GASES; RARE-GASES; FIELDS; PHOTODISSOCIATION AB A tunable, high-intensity picosecond-dye-laser system has been employed with electron energy analysis to investigate the dynamics of (3 + 1) resonance-enhanced multiphoton ionization via various vibrational levels of the B 1-SIGMA-u+ and C 1-PI-u electronic states in H-2. At the intensities studied [(0.2-6) x 10(13) W/cm2], we find evidence for production of molecular ions in various vibrational levels; at the lower intensities the population distribution of final vibrational states varies with wavelength in a manner consistent with resonant enhancement at the three-photon level, followed by ionization into a vibrational level of H-2+ roughly predictable by a Franck-Condon analysis of ionization out of the C state. At higher intensities, there is a shift to increased population of lower vibrational states of H-2+, consistent with an ac Stark shift of the correspondingly lower vibrational levels of the C state into resonance with the three-photon energy of the laser. Clear evidence of direct dissociation of H-2 followed by single-photon ionization of the excited H atom is observed as well. Above-threshold ionization of these two processes occurs readily. We also find that dissociative ionization is an increasingly important ionization pathway as the wavelength is increased. Finally, we see evidence of a fourth ionization pathway, which we tentatively assign to photoionization into a transient bound state created by the avoided crossing of the first repulsive electronic state of H-2+, \2p-sigma-u, n >, with the single-photon-dressed ground state of H-2+, \1s-sigma-g, n + 1 >. RP ALLENDORF, SW (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV HIGH TEMP PHYS,LIVERMORE,CA 94550, USA. NR 45 TC 74 Z9 74 U1 2 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 518 EP 534 DI 10.1103/PhysRevA.44.518 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400062 ER PT J AU CHILDS, WJ AF CHILDS, WJ TI HYPERFINE-STRUCTURE OF HIGH-L STATES IN ND-143(I), ND-145(I) BY ATOMIC-BEAM LASER-RF DOUBLE-RESONANCE SO PHYSICAL REVIEW A LA English DT Note AB The atomic-beam laser-rf double-resonance technique has been used to study the hyperfine structure (hfs) of the metastable 7L5-11 and 7K4 states of the 4f(4)5d6s configuration in Nd-143, Nd-145 I. Four zero-field intervals were measured in each state and the results used to assign the conventional hfs constants A and B. Comparison of the results with predictions of the Sandars-Beck model allowed evaluation of the relevant single-electron radial hfs integrals. These are compared with earlier results from the Nd I atomic ground term and with extrapolations from other rare-earth elements. The unusually large orbital-angular-momentum values (L = 7 and 8 for the states studied) do not appear to have introduced any anomalous effects. Ab initio calculations are not yet feasible for the complex 4f(4)5d6s levels studied. RP CHILDS, WJ (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 11 TC 10 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 760 EP 763 DI 10.1103/PhysRevA.44.760 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400087 ER PT J AU DUNFORD, RW LIU, CJ LAST, J BERRAHMANSOUR, N VONDRASEK, R CHURCH, DA CURTIS, LJ AF DUNFORD, RW LIU, CJ LAST, J BERRAHMANSOUR, N VONDRASEK, R CHURCH, DA CURTIS, LJ TI DIRECT OBSERVATION OF HYPERFINE QUENCHING OF THE (2)3P0 LEVEL IN HELIUM-LIKE NICKEL SO PHYSICAL REVIEW A LA English DT Note ID 23S1 STATE; LIFETIME; IONS AB We report a clear demonstration of the effect of hyperfine quenching of a forbidden transition by direct comparison of the lifetimes of the 2 3P0 level in the heliumlike isotopes Ni-61(26+) and Ni-58(26+). We find the quenched lifetime of the 2 3P0 level in Ni-61(26+) to be 470(50) ps. From this we deduce the 2 3P0-2 3P1 energy splitting to be 2.33(15) eV. We also report a measurement of the lifetime of the 2 3P2 level in Ni-58(26+), which is found to be 70(3) ps. C1 UNIV TOLEDO,DEPT PHYS & ASTRON,TOLEDO,OH 43606. TEXAS A&M UNIV SYST,DEPT PHYS,COLLEGE STN,TX 77843. RP DUNFORD, RW (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 15 TC 49 Z9 49 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP 764 EP 767 DI 10.1103/PhysRevA.44.764 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400088 ER PT J AU SAHA, BC LANE, NF KIMURA, M AF SAHA, BC LANE, NF KIMURA, M TI MOLECULAR-STATE TREATMENT OF HE+(2P) EXCITATION THROUGH ELECTRON-CAPTURE IN HE-2+-H-2 COLLISIONS AT LOW ENERGIES SO PHYSICAL REVIEW A LA English DT Note ID CHARGE-TRANSFER; ORBITAL-EXPANSION; IMPACT ENERGIES; HE2+ IONS; H-ATOMS AB We report the calculation of low-energy state-selective electron-capture cross sections in an alpha-particle collision with molecular hydrogen. The semiclassical molecular-orbital expansion method is used and electron translation effects are taken into account. The calculated He + (2p) formation cross sections are in good overall agreement with the recent measurements of Hoekstra et al. [J. Phys. B 22, L603 (1989)]. However, the experimental cross sections show a pronounced plateau between E = 0.7 and 2.0 keV/amu. In the same energy region the calculated results exhibit an oscillatory structure that arises from a combination of Landau-Zener and Rosen-Demkov oscillations. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP SAHA, BC (reprint author), RICE UNIV,RICE QUANTUM INST,DEPT PHYS,HOUSTON,TX 77251, USA. NR 22 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL 1 PY 1991 VL 44 IS 1 BP R1 EP R4 DI 10.1103/PhysRevA.44.R1 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FV184 UT WOS:A1991FV18400001 ER PT J AU CHOE, I INGALLS, R BROWN, JM SATOSORENSEN, Y MILLS, R AF CHOE, I INGALLS, R BROWN, JM SATOSORENSEN, Y MILLS, R TI MOSSBAUER STUDIES OF IRON HYDRIDE AT HIGH-PRESSURE SO PHYSICAL REVIEW B LA English DT Article ID FE-H; HYDROGEN; METALS; PHASES AB We have measured in situ Mossbauer spectra of iron hydride made in a diamond anvil cell at high pressure and room temperature. The spectra show a sudden change at 3.5 +/- O.5 GPa from a single hyperfine pattern to a superposition of three. The former pattern results from normal alpha-iron with negligible hydrogen content, and the latter from residual alpha-iron plus newly formed iron hydride. Between 3.5 and 10.4 GPa, the extra hydride pattern have hyperfine fields for one ranging from 276 to 263 kOe, and the other, from 317 to 309 kOe. Both have isomer shifts of about 0.4 mm/sec, and negligible quadrupole splittings. X-ray studies on quenched samples have shown that iron hydride is of double hexagonal close-packed structure, whose two nonequivalent iron sites may account for the observation of two different patterns. Even allowing for the effect of volume expansion, the observed isomer shifts for the hydride are considerably more positive than those of other metallic phases of iron. At the same time, the hyperfine fields are slightly smaller than that of alpha-iron. As a possible explanation, one may expect a bonding of hydrogen with iron, which would result in a small reduction of 4s electrons, possibly accompanied by a small increase of 3d electrons compared with the neutral atom in metallic iron. The difference between the hyperfine fields in the two spectra are presumably due to the different symmetry at the two iron sites. C1 UNIV WASHINGTON, GEOPHYS PROGRAM, SEATTLE, WA 98195 USA. UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. RP CHOE, I (reprint author), UNIV WASHINGTON, DEPT PHYS, FM-15, SEATTLE, WA 98195 USA. NR 19 TC 19 Z9 19 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 1 BP 1 EP 4 DI 10.1103/PhysRevB.44.1 PG 4 WC Physics, Condensed Matter SC Physics GA FU902 UT WOS:A1991FU90200001 ER PT J AU MOTOYA, K SHAPIRO, SM REBELSKY, L TORIKACHVILI, MS AF MOTOYA, K SHAPIRO, SM REBELSKY, L TORIKACHVILI, MS TI SPIN DYNAMICS OF THE CONCENTRATED SPIN-GLASS Y(MN0.9AL0.1)2 SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON MAGNET YMN2; NEUTRON-SCATTERING; FLUCTUATIONS; Y(MN1-XALX)2; STATE; ALLOY; MNSI AB Inelastic-neutron-scattering measurements employing polarization analysis have been performed on a pseudobinary intermetallic compound Y(Mn0.9Al0.1)2, which transforms to spin-glass state below T(SG) = 42 K. The temperature variation of the energy width of the scattered neutron spectrum follows an Arrhenius law over a wide temperature range, and the width above T(SG) is much larger when compared with other concentrated spin glasses. The collapse of helical magnetic order caused by a slight dilution of the magnetic Mn atoms with nonmagnetic Al atoms and the very large excitation spectrum above T(SG), show that the itinerant character of magnetic electrons as well as the strong frustrations of magnetic interactions play an important role in this material. The importance of proper treatment of magnetic moments, taking into account the itinerant character of the magnetic electrons in metallic spin glasses, is discussed. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. SAN DIEGO STATE UNIV,DEPT PHYS,SAN DIEGO,CA 92182. RP MOTOYA, K (reprint author), SAITAMA UNIV,DEPT PHYS,URAWA,SAITAMA 338,JAPAN. NR 23 TC 11 Z9 11 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 1 BP 183 EP 189 DI 10.1103/PhysRevB.44.183 PG 7 WC Physics, Condensed Matter SC Physics GA FU902 UT WOS:A1991FU90200022 ER PT J AU HERWIG, KW SOKOL, PE SNOW, WM BLASDELL, RC AF HERWIG, KW SOKOL, PE SNOW, WM BLASDELL, RC TI DEVIATIONS FROM THE IMPULSE APPROXIMATION IN LIQUID-HE-4 - MOMENTUM-TRANSFER DEPENDENCE SO PHYSICAL REVIEW B LA English DT Article ID INELASTIC NEUTRON-SCATTERING; SUPERFLUID-HELIUM; QUANTUM LIQUIDS; STATE; DISTRIBUTIONS; FLUIDS AB We have carried out a series of deep-inelastic-neutron-scattering (DINS) measurements on liquid He-4 to study the Q dependence of deviations from the impulse approximation, called final-state effects (FSE). DINS measurements on liquid He-4 have been carried out for temperatures of 0.75 and 4.25 K at a density of 0.147 g/cm3 for momentum transfers between 10 and 23 angstrom-1. Under the assumption that current theoretical calculations of the momentum distribution of liquid He-4 are accurate, we extract the form of FSE in the superfluid phase from the scattering data. We find that FSE are definitely present in the scattering data, and their effects are more important at lower Q's. We also compare the predictions of several theories for FSE to the experimental data. We find that the recent theories of FSE of Silver and of Carraro and Koonin are in excellent agreement with the data in the superfluid phase at Q = 23 angstrom-1. At the lower values of Q, deviations from these theories appear. No current theory describes the observed FSE completely at the lower Q's. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP HERWIG, KW (reprint author), PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802, USA. RI Herwig, Kenneth/F-4787-2011 NR 38 TC 7 Z9 7 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 JUL 1 PY 1991 VL 44 IS 1 BP 308 EP 316 DI 10.1103/PhysRevB.44.308 PG 9 WC Physics, Condensed Matter SC Physics GA FU902 UT WOS:A1991FU90200037 ER PT J AU SOUKOULIS, CM DATTA, S LEE, YH AF SOUKOULIS, CM DATTA, S LEE, YH TI SPIN-WAVE THEORY FOR ANISOTROPIC HEISENBERG ANTIFERROMAGNETS SO PHYSICAL REVIEW B LA English DT Note ID SQUARE-LATTICE; 2 DIMENSIONS; MONTE-CARLO; LA2CUO4-Y; STATE AB The anisotropic Heisenberg antiferromagnet (AF), which is defined as a three-dimensional simple-cubic lattice with in-plane antiferromagnetic interaction J parallel-to and interplane coupling J perpendicular-to = gamma-J parallel-to and is believed to describe the magnetic properties of the cupric oxide materials, is studied using low-temperature spin-wave theory. The dependence of the T = 0 staggered magnetization, ground-state energy, transverse susceptibility, spin-wave velocity, and the Neel temperature T(N) on the anisotropy parameter gamma (0 less-than-or-equal-to gamma less-than-or-equal-to 1) are obtained. These results are found to be in satisfactory agreement with existing experiments on cupric oxide materials. The apparent difference between the muon-spin resonance and neutron-scattering results for the ordered moment in the AF state is well explained. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP SOUKOULIS, CM (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Soukoulis, Costas/A-5295-2008; Lee, Young Hee/A-5424-2013 NR 25 TC 36 Z9 36 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 1 BP 446 EP 449 DI 10.1103/PhysRevB.44.446 PG 4 WC Physics, Condensed Matter SC Physics GA FU902 UT WOS:A1991FU90200064 ER PT J AU THOMPSON, JR SUN, YR HOLTZBERG, F AF THOMPSON, JR SUN, YR HOLTZBERG, F TI LONG-TERM NONLOGARITHMIC MAGNETIC-RELAXATION IN SINGLE-CRYSTAL YBA2CU3O7 SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Note ID HIGH-TEMPERATURE SUPERCONDUCTORS; FLUX-CREEP; CU-O; GLASS; IRREVERSIBILITY; IRRADIATION; DEPENDENCE; ENERGY; FIELD AB The time dependence of the irreversible superconductive magnetization (flux creep) has been studied in a high-J(c), proton-irradiated YBa2Cu3O7-x single crystal for long periods, up to 3.5 x 10(5) s. A nonlogarithmic decay of the magnetization M with time was observed. This deviation from the conventional logarithmic time dependence was not an approach of the system to the equilibrium state. The decay fits extremely well to the relation M(t) = M0/[1 + (mu-kT/U0) xln(t/t(eff))]1/mu from vortex-glass theory or to the empirical expression M(t) = M0 + a(T)ln[ln(t/t(eff))]. Another possible explanation is based on the theory of thermally activated flux creep, wherein the magnitude of the pinning-energy barrier U0 is a function of current density. From the latter we obtain an exponential dependence of U0 on current density for J near its critical value. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP THOMPSON, JR (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 24 TC 96 Z9 98 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 1 BP 458 EP 461 DI 10.1103/PhysRevB.44.458 PG 4 WC Physics, Condensed Matter SC Physics GA FU902 UT WOS:A1991FU90200067 ER PT J AU LU, ZW WEI, SH ZUNGER, A FROTAPESSOA, S FERREIRA, LG AF LU, ZW WEI, SH ZUNGER, A FROTAPESSOA, S FERREIRA, LG TI 1ST-PRINCIPLES STATISTICAL-MECHANICS OF STRUCTURAL STABILITY OF INTERMETALLIC COMPOUNDS SO PHYSICAL REVIEW B LA English DT Article ID TRANSITION-METAL ALLOYS; EMBEDDED-ATOM-METHOD; SHORT-RANGE ORDER; ELECTRONIC-STRUCTURE CALCULATIONS; COHERENT-POTENTIAL APPROXIMATION; EFFECTIVE-PAIR INTERACTIONS; DENSITY-FUNCTIONAL THEORY; CLUSTER-VARIATION METHOD; GROUND-STATE STRUCTURES; SITE DIAGONAL DISORDER AB While as elemental solids, Al, Ni, Cu, Rh, Pd, Pt, and Au crystallize in the face-centered-cubic (fcc) structure, at low temperatures, their 50%-50% compounds exhibit a range of structural symmetries: CuAu has the fcc-based L 1(0) structure, CuPt has the rhombohedral L1(1) structure, and CuPd and AlNi have the body-centered-cubic B2 structure, while CuRh does not exist (it phase separates into Cu and Rh). Phenomenological approaches attempt to rationalize this type of structural selectivity in terms of classical constructs such as atomic sizes, electronegativities, and electron/atom ratios. More recently, attempts have been made at explaining this type of selectivity in terms of the (quantum-mechanical) electronic structure, e.g., by contrasting the self-consistently calculated total electron + ion energy of various ordered structures. Such calculations, however, normally select but a small, O10 subset of "intuitive structures" out of the 2N possible configurations of two types of atoms on a fixed lattice with N sites, searching for the lowest energy. We use instead first-principles calculations of the total energies of O10 structures to define a multispin Ising Hamiltonian, whose ground-state structures can be systematically searched by using methods of lattice theories. Extending our previous work on semiconductor alloys [S.-H. Wei, L. G. Ferreira, and A. Zunger, Phys. Rev. B 41, 8240 (1990)], this is illustrated here for the intermetallic compounds AlNi, CuRh, CuPd, CuPt, and CuAu, for which the correct ground states are identified out of approximately 65 000 configurations, through the combined use of the density-functional formalism (to extract Ising-type interaction energies) with a simple configurational-search strategy (to find ground states). This establishes a direct and systematic link between the electronic structure and phase stability. C1 UNIV SAO PAULO, INST FIS, BR-01498 SAO PAULO, BRAZIL. RP SOLAR ENERGY RES INST, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 149 TC 248 Z9 249 U1 1 U2 33 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 512 EP 544 DI 10.1103/PhysRevB.44.512 PG 33 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100004 ER PT J AU FISHMAN, RS VIGNALE, G AF FISHMAN, RS VIGNALE, G TI BREAKDOWN OF THE SPIN-WAVE APPROXIMATION FOR A HEISENBERG-FERROMAGNET SO PHYSICAL REVIEW B LA English DT Article ID DYNAMICS; EUS AB By comparing the exact free energy with the free energy of the random-phase approximation (RPA), we find that the spin-wave description of a spin-s Heisenberg ferromagnet breaks down near the temperature TBAR = 0.18zJs, where J is the ferromagnetic coupling constant and z is the number of nearest neighbors. The scaling of the crossover temperature with zJs agrees with the early results of Vaks, Larkin, and Pikin. We calculate this crossover temperature by expanding the RPA free energy in powers of 1/z on a d-dimensional hypercubic lattice. While the zeroth- and first-order terms in the RPA expansion agree with the terms in the exact expansion, the second-order term disagrees with the exact 1/z2 free energy. Below TBAR, the difference between the RPA and exact free energies is negligible. So for T < TBAR, the RPA summation is justified and the spin-wave description is appropriate. Above TBAR, however, the spin-wave interactions become highly nonlinear and the RPA free energy deviates from the exact result. Because all momentum states contribute to the energy above TBAR, the transverse free energy enters an equipartition regime and the transverse specific heat tends to zero. As a result, the crossover is marked by a peak in the fluctuation specific heat. The crossover temperature is unchanged if a more sophisticated spin-wave theory is used in place of the RPA. The predicted crossover has been observed as a shoulder in measurements of the total specific heat. C1 N DAKOTA STATE UNIV,DEPT PHYS,SU STN,FARGO,ND 58105. UNIV MISSOURI,DEPT PHYS & ASTRON,COLUMBIA,MO 65211. RP FISHMAN, RS (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. RI Fishman, Randy/C-8639-2013 NR 26 TC 14 Z9 14 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 658 EP 674 DI 10.1103/PhysRevB.44.658 PG 17 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100019 ER PT J AU RADOVIC, Z LEDVIJ, M DOBROSAVLJEVICGRUJIC, L BUZDIN, AI CLEM, JR AF RADOVIC, Z LEDVIJ, M DOBROSAVLJEVICGRUJIC, L BUZDIN, AI CLEM, JR TI TRANSITION-TEMPERATURES OF SUPERCONDUCTOR-FERROMAGNET SUPERLATTICES SO PHYSICAL REVIEW B LA English DT Article ID UPPER CRITICAL-FIELD; NORMAL-METAL; MULTILAYERS AB The transition temperature T(c) of superconductor-ferromagnet superlattices is calculated by solving exactly the Usadel equations. Characteristic ground-state configurations are predicted with nontrivial phase difference 0 < rho less-than-or-equal-to pi between neighboring superconducting layers. An unusual oscillatory dependence of T(c) on the ferromagnetic-layer thickness is obtained. For short-period superlattices it is found that the transition changes from second to first order. A comparison of theoretical results with experimental data for V/Fe superlattices is given. C1 INST PHYS, YU-11001 BELGRADE, YUGOSLAVIA. MV LOMONOSOV STATE UNIV, DEPT PHYS, MOSCOW 117234, USSR. IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. IOWA STATE UNIV SCI & TECHNOL, DEPT PHYS, AMES, IA 50011 USA. RP UNIV BELGRADE, DEPT PHYS, POB 550, YU-11001 BELGRADE, YUGOSLAVIA. RI Buzdin, Alexander/I-6038-2013 NR 22 TC 312 Z9 314 U1 1 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 759 EP 764 DI 10.1103/PhysRevB.44.759 PG 6 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100031 ER PT J AU RETTORI, C RAO, D OSEROFF, S ZYSLER, RD TOVAR, M FISK, Z CHEONG, SW SCHULTZ, S VIER, DC AF RETTORI, C RAO, D OSEROFF, S ZYSLER, RD TOVAR, M FISK, Z CHEONG, SW SCHULTZ, S VIER, DC TI CRYSTAL-FIELD EFFECTS IN THE ELECTRON-SPIN-RESONANCE OF GD3+ AND ER3+ IN PR2CUO4 SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC PHASE-TRANSITIONS; SUPERCONDUCTIVITY; ROTATION; LA2CUO4; ANTIFERROMAGNETISM; (LA1-XBAX)2CUO4; SYSTEMS; DIAGRAM; ND2CUO4; OXIDES AB The low-temperature (T < 300 K) electron-spin-resonance (ESR) spectra of Gd3+ and Er3+ in Pr2CuO4 show symmetry properties appropriate to the crystal tetragonal symmetry. The completely resolved Gd3+ spectra allowed us to measure, at T = 2 K, the principal g values g parallel-to = 1.985(8), g perpendicular-to =2.040(8), and the crystal-field parameters [b2(0) = -399(2) X 10(-4) cm-1, b4(0) = -33.1(7) X 10(-4) cm-1, and b4(4) = 205(3) X 10(-4) cm-1]. The large broadening of the ESR lines, observed above T approximately 40 K, is due to a relaxation via the thermally populated crystal-field excited Pr levels. For Er3+ in Pr2CuO4 we observe a single ESR line corresponding to a ground-state doublet with g parallel-to = 17.94(5) and g perpendicular-to less-than-or-equal-to 0.2. The absence of any splittings of the ESR lines below the Neel temperature implies that the magnetostatic dipole field at the rare-earth-ion site due to the antiferromagnetically ordered Cu moments is < 45 Oe. C1 UNIV ESTADUAL CAMPINAS,INST FIS,BR-13081 CAMPINAS,SP,BRAZIL. CTR ATOM BARILOCHE,RA-8400 BARIOLOCHE,ARGENTINA. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. RP RETTORI, C (reprint author), SAN DIEGO STATE UNIV,SAN DIEGO,CA 92182, USA. RI Rettori, Carlos/C-3966-2012; Inst. of Physics, Gleb Wataghin/A-9780-2017 OI Rettori, Carlos/0000-0001-6692-7915; NR 23 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 826 EP 829 DI 10.1103/PhysRevB.44.826 PG 4 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100042 ER PT J AU YOO, CS RADOUSKY, HB HOLMES, NC EDELSTEIN, NM AF YOO, CS RADOUSKY, HB HOLMES, NC EDELSTEIN, NM TI LUMINESCENCE OF SM2+ IONS AS A PROBE OF PRESSURE-INDUCED PHASE-TRANSITIONS IN SRF2 SO PHYSICAL REVIEW B LA English DT Note ID RAMAN-SPECTROSCOPY AB The luminescence of Sm2- ions in SrF2 is used to monitor the beta (cubic) -to-alpha (orthorhombic) phase transition of SrF2 at approximately 5 GPa and 300 K. In contrast to those in the beta-phase, the SM2+ spectra in the alpha-phase show a series of sharp 4f-4f transition bands, even at 300 K, originating from the 5D0 to 7F(J) multiplets including a strong transition for DELTA-J = 0. At low temperatures, these transitions are not observed; instead, the 4f5(5d)l band of the Sm2+ ions in the beta-phase reversibly shifts below 5D0 (4f(b)) level at 4.5 GPa and 30 K. The alpha-phase is metastable and can be recovered at 1 atm and 30 K. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP YOO, CS (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 830 EP 833 DI 10.1103/PhysRevB.44.830 PG 4 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100043 ER PT J AU LEDVIJ, M DOBROSAVLJEVICGRUJIC, L RADOVIC, Z CLEM, JR AF LEDVIJ, M DOBROSAVLJEVICGRUJIC, L RADOVIC, Z CLEM, JR TI VORTEX AND NONVORTEX NUCLEATION OF SUPERCONDUCTIVITY IN FERROMAGNETIC-SUPERCONDUCTING-FERROMAGNETIC TRIPLE LAYERS SO PHYSICAL REVIEW B LA English DT Note ID SUPERLATTICES AB Superconducting nucleation fields for ferromagnetic-superconducting-ferromagnetic (M/S/M) triple layers are calculated when the magnetic field is applied parallel to the SIM interfaces, the S layer is of arbitrary thickness d, and the M metals are identical and very thick. Both vortex and nonvortex nucleation are considered and the thickness d(cr) at which the vortices start to nucleate is determined. Since the superconductivity is significantly suppressed near the S IM interfaces, the thickness d(cr) substantially increases with respect to the case of a single S film. C1 FAC SCI BELGRADE,DEPT PHYS,YU-11001 BELGRADE,YUGOSLAVIA. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP LEDVIJ, M (reprint author), INST PHYS,POB 57,YU-11001 BELGRADE,YUGOSLAVIA. NR 10 TC 9 Z9 9 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1991 VL 44 IS 2 BP 859 EP 862 DI 10.1103/PhysRevB.44.859 PG 4 WC Physics, Condensed Matter SC Physics GA FV181 UT WOS:A1991FV18100051 ER PT J AU CHEN, CR PAYNE, GL FRIAR, JL GIBSON, BF AF CHEN, CR PAYNE, GL FRIAR, JL GIBSON, BF TI ND ZERO-ENERGY SCATTERING SO PHYSICAL REVIEW C LA English DT Article ID FADDEEV CONTINUUM CALCULATIONS; TRITON BINDING-ENERGY; PROTON-DEUTERON SCATTERING; PHASE-SHIFT ANALYSIS; CONFIGURATION SPACE; S-WAVE; 3-NUCLEON SYSTEM; MOMENTUM SPACE; TRINUCLEON SYSTEM; NUCLEAR-MATTER AB Faddeev-type configuration-space three-body scattering equations are solved for selected two-body- and two-body-plus-three-body-potential model Hamiltonians to obtain absolute predictions for the nucleon-deuteron scattering lengths 2a(nd), 4a(nd), 2a(pd), and 4a(pd). Convergence for these zero-energy scattering parameters as a function of the number of NN-potential partial waves included in the calculation is attained for the first time. Kohn variational estimates provide a measure of the precision of our numerical results. The nd predictions agree well with the measured values. The pd predictions differ substantially from accepted experimental values which are extrapolated from measurements made above 400 keV. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP CHEN, CR (reprint author), UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242, USA. NR 77 TC 45 Z9 46 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 50 EP 59 DI 10.1103/PhysRevC.44.50 PG 10 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300009 ER PT J AU BAKER, FT BIMBOT, L FERGERSON, RW GLASHAUSSER, C GREEN, A HAUSSER, O HICKS, K JONES, K MILLER, CA VETTERLI, M ABEGG, R BEATTY, D BONIN, B CASTEL, B CHEN, XY CUPPS, V DJALALI, C HENDERSON, R JACKSON, KP JEPPESEN, R NAKAYAMA, K NANDA, SK SAWAFTA, R YEN, S AF BAKER, FT BIMBOT, L FERGERSON, RW GLASHAUSSER, C GREEN, A HAUSSER, O HICKS, K JONES, K MILLER, CA VETTERLI, M ABEGG, R BEATTY, D BONIN, B CASTEL, B CHEN, XY CUPPS, V DJALALI, C HENDERSON, R JACKSON, KP JEPPESEN, R NAKAYAMA, K NANDA, SK SAWAFTA, R YEN, S TI SPIN DECOMPOSITION OF THE RESPONSES OF CA-44 AND CA-48 TO 300 MEV PROTONS SO PHYSICAL REVIEW C LA English DT Article ID MEDIUM RESOLUTION SPECTROMETER; DELTA-S=0 GIANT-RESONANCES; INTERMEDIATE ENERGIES; P->,P->' REACTION; DIPOLE STRENGTH; SUM-RULES; EXCITATIONS; SCATTERING; POLARIMETER; TRANSITIONS AB Angular distributions of the double-differential cross section d2-sigma/d-OMEGA-dE(sigma) and the spin-flip probability S(nn) have been measured for inclusive proton inelastic scattering from Ca-44 at 290 MeV and from 48Ca at 318 MeV. Excitation energies up to about 50 MeV for Ca-44 and 40 MeV for 48Ca have been investigated over the laboratory angular ranges of 3-degrees to 12-degrees for Ca-44 and 3-degrees to 9-degrees for 48Ca. Multipole decompositions of angular distributions of both the spin-flip cross section sigma-S(nn) and the estimated cross section for DELTA-S = 0 transitions have been performed. Distributions of strengths were deduced for DELTA-L = 1, DELTA-S = 0 (the giant dipole), DELTA-L = 2, DELTA-S = 0 (the giant quadrupole), DELTA-L = 0, DELTA-S = 1 (the magnetic dipole), DELTA-L = 1, DELTA-S = 1 (the spin dipole), and DELTA-L = 2, DELTA-S = 1 (the spin quadrupole). The DELTA-S = 0 summed strengths for Ca-44 are lower than for Ca-40 and 48Ca. The spin-dipole summed strengths are found to be approximately independent of A. For 48Ca, essentially all M1 strength observed was in the 10.23 MeV 1+ state; for Ca-44, M1 strength was observed to be fragmented over a range of 7 to 18 Mev. C1 CONTINUOUS ELECTRON BEAM ACCELERATOR FACIL,NEWPORT NEWS,VA 23606. INST PHYS NUCL,F-91406 ORSAY,FRANCE. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. SIMON FRASER UNIV,BURNABY V5A 1S6,BC,CANADA. TRIUMF,VANCOUVER V6T 2A3,BC,CANADA. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. CENS,F-91191 GIF SUR YVETTE,FRANCE. QUEENS UNIV,KINGSTON K7L 3N6,ONTARIO,CANADA. UNIV COLORADO,BOULDER,CO 80309. UNIV S CAROLINA,COLUMBIA,SC 29208. UNIV ALBERTA,EDMONTON T6G 2E1,ALBERTA,CANADA. RP BAKER, FT (reprint author), UNIV GEORGIA,ATHENS,GA 30602, USA. NR 31 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 93 EP 103 DI 10.1103/PhysRevC.44.93 PG 11 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300014 ER PT J AU HOREN, DJ AUBLE, RL BEENE, JR BERTRAND, FE HALBERT, ML SATCHLER, GR THOENNESSEN, M VARNER, RL BROWN, VR ANTHONY, PL MADSEN, VA AF HOREN, DJ AUBLE, RL BEENE, JR BERTRAND, FE HALBERT, ML SATCHLER, GR THOENNESSEN, M VARNER, RL BROWN, VR ANTHONY, PL MADSEN, VA TI ISOSPIN CHARACTER OF TRANSITIONS TO BOUND-STATES IN PB-204,PB-206,PB-208 USING INELASTIC-SCATTERING OF O-17 IONS SO PHYSICAL REVIEW C LA English DT Article ID GIANT QUADRUPOLE-RESONANCE; PION-SCATTERING; CORE POLARIZATION; MULTIPOLE RESONANCES; COLLECTIVE STATES; NI ISOTOPES; PB-208; EXCITATION; SN-118; 2-QUASI-PARTICLE AB We have measured the scattering of 375-MeV O-17 ions by isotopes of Pb-204, Pb-206, Pb-208 to investigate the isospin character of transitions to low-lying 2+ and 3- states. The data were analyzed using the deformed optical potential model. The 2+ collective strength, which is concentrated in a single state at 4.085 MeV in Pb-208, is observed to fragment in both Pb-204 and Pb-206. The differential cross sections for excitation of the collective 2+ and 3- states are well reproduced by model calculations in which it is assumed that M(n)/M(p) = N/Z (i.e., isoscalar character). Angular distributions for the lowest-lying 2+ states in Pb-203, Pb-206 are significantly different from those for the higher-lying collective 2+ states, and can be reproduced with M(n)/M(p) almost-equal-to 2.5. The data are compared with random-phase-approximation calculations including pairing, and good agreement is found within estimated uncertainties. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. OREGON STATE UNIV,DEPT PHYS,CORVALLIS,OR 97331. RP HOREN, DJ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 39 TC 23 Z9 23 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 128 EP 135 DI 10.1103/PhysRevC.44.128 PG 8 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300018 ER PT J AU WARBURTON, EK AF WARBURTON, EK TI 1ST-FORBIDDEN BETA-DECAY IN THE LEAD REGION AND MESONIC ENHANCEMENT OF THE WEAK AXIAL CURRENT SO PHYSICAL REVIEW C LA English DT Article ID ORBITAL ELECTRON-CAPTURE; MATRIX-ELEMENTS; EXCHANGE CORRECTION; SOLAR NEUTRINOS; NUCLEI; MASS; TRANSITIONS; SYSTEMATICS; PREDICTIONS; OPERATORS AB A shell-model study is made of first-forbidden beta-decay and related processes in A = 205-212 nuclei. The interactions used are modifications of the Kuo-Herling realistic effective interactions for particles above and holes below Pb-208 and a cross-shell G-matrix interaction connecting these two. Large-scale diagonalizations are made of 1p-1h excitations across the double-shell closure at Pb-208. The calculations of the first-forbidden rates use effective single-particle matrix elements which incorporate core polarization of the final state to first order. All first-order initial state 1p-1h admixtures are included explicitly in the diagonalization. A least-squares fit of theory to experiment for eighteen DELTA-J = 0 and 1 decay rates was made with two unknowns: (1) an enhancement factor epsilon-mec for the rank-zero matrix element of gamma-5, and (2) an overall scaling factor for the rank-one component of the decay rate. A good fit is achieved yielding epsilon-mec = 2.01 +/- 0.05 and a rank-one scaling factor of 0.97 +/- 0.06. The agreement of the latter with unity indicates a satisfactory understanding of the rank-one component of the decay. The result epsilon-mec = 2.01 +/- 0.05 indicates an enhancement of the matrix element of gamma-5 by 100% over the impulse approximation. A 40% effect is predicted from meson exchange. Thus, a deficiency in the meson-exchange calculation or some further as-yet-unforseen contribution is suggested. Predictions for twenty other decays in A = 205-211 nuclei are compared to experiment and found to be in good general agreement. A calculation of the capture of neutrinos by Tl-205 is described in detail. RP WARBURTON, EK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 75 TC 75 Z9 75 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 233 EP 260 DI 10.1103/PhysRevC.44.233 PG 28 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300030 ER PT J AU WARBURTON, EK AF WARBURTON, EK TI SHELL-MODEL INTERPRETATION OF THE BETA-DECAY OF BI-212(G), BI-212(M1), AND B1-212(M2) SO PHYSICAL REVIEW C LA English DT Article ID PO-212; NUCLEI AB The beta- decay of the Bi-212 ground state (T1/2 = 61 min) and the isomers Bi-212m1 (T1/2 = 27 min), and Bi-212m2 (T1/2 = 8 min) are considered in the spherical shell model. The wave functions and energy spectra of all even and odd states in the Kuo-Herling model space were calculated for both Bi-212 and Po-212. Possible candidates for the two Bi-212 isomers were located from these results and the allowed and first-forbidden beta- decays rates were formed using a recently developed parametrization of first-forbidden decays in the lead region. It was concluded that Bi-212m1 is the yrast 8- state and Bi-212m2 the yrast 18- state of Bi-212. The decay rates calculated for these two beta- emitters are in excellent agreement with experiment. The predictions for the decay of the ground state of Bi-212 are not in good agreement with experiment, illustrating the difficulty of calculating weak first-forbidden decay modes reliably. RP WARBURTON, EK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 23 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 JUL PY 1991 VL 44 IS 1 BP 261 EP 267 DI 10.1103/PhysRevC.44.261 PG 7 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300031 ER PT J AU WARBURTON, EK AF WARBURTON, EK TI SHELL-MODEL PREDICTIONS FOR CL-41(BETA-),CL-42(BETA-) AR-41,AR-42 AND THE A=41-43 AR ISOTOPES SO PHYSICAL REVIEW C LA English DT Article ID NUCLEI; AR-40 AB Shell-model calculations in the model space of the (0d; 1s) and (0f, 1p) major shells are made for the 1/2+ and 3/2+ states of 41Cl, the odd-parity states of Ar-41, and the even-parity states of Ar-42. Calculations for 42Cl, the even-parity states of Ar-41, and the odd-parity states of Ar-43 were performed with various degrees of truncation. The results for the 41Cl ground state indicate J-pi = 3/2+ with a binding energy of -345183 keV in excellent agreement with the experimental value of -345020 +/- 150 keV. The predicted binding energies of Ar-41-43 are also in good agreement with experiment. The wave functions for the A = 41 and 42 nuclei are used to calculate first-forbidden beta--decay rates. The 1/2+ and 3/2+ states of Ar-41 are considered in a truncated model space and the results are used to estimate the allowed beta--decays rates of 41Cl. Spectroscopic factors and electromagnetic transition rates are calculated for Ar-41 and compared to experiment. Ar-43 is predicted to have a 5/2- ground state. RP WARBURTON, EK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 28 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 268 EP 275 DI 10.1103/PhysRevC.44.268 PG 8 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300032 ER PT J AU VERGADOS, JD AF VERGADOS, JD TI PION DOUBLE-CHARGE-EXCHANGE REACTION - SHELL-MODEL FORMALISM SO PHYSICAL REVIEW C LA English DT Article ID SCATTERING; O-18(PI+ AB A quite general formalism which allows one to compute the pion double-charge-exchange differential cross section in the context of the shell model has been developed. Compact formulas taking into account the full momentum and spin dependence of the elementary amplitude are given. These formulas hold for any nuclear angular momenta as well as any pion-nucleus partial waves. Thus the differential cross section depends on a quantity B(l)1l2ifJ(k1,k2) which is a function of the magnitude of the pion momenta k1,k2 and is composed of three factors: (1) the nuclear matrix element involving the states (i) and (f) expressed in terms of tensor operators T (a dagger a); (2) the essentially "geometric" aspects of the elementary double-charge-exchange amplitude which are pretty independent of any specific model; (3) a radial integral which contains the ingredients of specific models as well as the distortion of the mesons involved. C1 UNIV IOANNINA,DEPT PHYS,IOANNINA,GREECE. RP VERGADOS, JD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 276 EP 284 DI 10.1103/PhysRevC.44.276 PG 9 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300033 ER PT J AU BLANN, M MUSTAFA, MG PEILERT, G STOCKER, H GREINER, W AF BLANN, M MUSTAFA, MG PEILERT, G STOCKER, H GREINER, W TI EXPECTATIONS OF FRAGMENT DECAY FROM HIGHLY EXCITED NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; ENERGY GAMMA-RAYS; SUBTHRESHOLD PION-PRODUCTION; P BREMSSTRAHLUNG INTERPRETATION; QUANTUM MOLECULAR-DYNAMICS; EXCHANGE TRANSPORT MODEL; UEHLING-UHLENBECK THEORY; HARD PHOTON PRODUCTION; PRECOMPOUND DECAY; MOMENTUM-TRANSFER AB The statistical model is used to illustrate the consequences of a successive binary decay mechanism as the initial nuclear excitation is pushed towards the limits of stability. The partition of the excitation energy between light and heavy fragments is explicitly calculated, as are the consequences of the decay of the primary light fragments to particle-bound residual nuclei which would be observed experimentally. The test nucleus Ru-100(44) is considered at initial excitations of 100, 200, 400, and 800 MeV. Exit channels of n, p, and alpha and 100 clusters of 3 less-than-or-equal-to Z less-than-or-equal-to 20, 6 less-than-or-equal-to A less-than-or-equal-to 48 are considered from all nuclides in the deexcitation cascade. The total primary and final cluster yields are shown versus Z and initial excitation. The primary versus final yields are also shown individually for C-12, Mg-26, and Ca-48. We show how multifragmentation yields will change with the excitation energy due to a successive binary decay mechanism. Measurements that may be prone to misinterpretation are discussed, as are those that should be representative of initial nucleus excitation. C1 UNIV FRANKFURT,INST THEORET PHYS,W-6000 FRANKFURT 1,GERMANY. RP BLANN, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. RI Stoecker, Horst/D-6173-2013 OI Stoecker, Horst/0000-0002-3282-3664 NR 60 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 431 EP 439 DI 10.1103/PhysRevC.44.431 PG 9 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300049 ER PT J AU ESBENSEN, H AF ESBENSEN, H TI ANGULAR-DISTRIBUTION OF NEUTRONS EMITTED IN (LI-11, L1-9) BREAKUP REACTIONS SO PHYSICAL REVIEW C LA English DT Article ID ELECTROMAGNETIC DISSOCIATION; COULOMB AB The angular distribution of neutrons emitted in (Li-11, Li-9) breakup reactions is calculated directly from one of the reaction mechanisms, viz. Coulomb dissociation. The shape of the calculated distribution agrees quite accurately with recently measured neutron data. This provides a test of the calculated dipole strength in Li-11 at low excitations. RP ESBENSEN, H (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 10 TC 31 Z9 31 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 440 EP 445 DI 10.1103/PhysRevC.44.440 PG 6 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300050 ER PT J AU OSET, E STROTTMAN, D AF OSET, E STROTTMAN, D TI PION-INDUCED ELASTIC AND INELASTIC-SCATTERING ABOVE THE 3,3 RESONANCE SO PHYSICAL REVIEW C LA English DT Article ID SINGLE-CHARGE-EXCHANGE; NUCLEAR-STRUCTURE; DELTA-(1232) RESONANCE; MATRIX-ELEMENTS; TRANSITIONS AB Results of Glauber model calculations of elastic and inelastic scattering from C-12, O-18, Ca-40, and 48Ca of pions having energy of 300 to 1200 MeV are presented. Experimental pi-N phase shifts including l = 0 through 5 are used in the calculation. The f wave is important above 300 MeV and the g and h wave above 900 Mev. Effects of spin-flip are included. The model reasonably reproduces the 800 MeV/c data of Marlow although the inelastic scattering of the 2+ of C-12 requires an enhancement of the quadrupole component consistent with the effective charge. The previously observed anomaly in C-12 in which a much larger oscillator parameter was required in pion scattering than in electron scattering disappears at higher energy. The sigma(pi-eta) to sigma(pi+eta) ratio is found to be appreciably different from expectations based on pion scattering from free nucleons. C1 UNIV VALENCIA,CSIC,CTR MIXTO,INST FIS CORPUSCULAR,VALENCIA,SPAIN. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP OSET, E (reprint author), UNIV VALENCIA,CSIC,CTR MIXTO,DEPT FIS TEOR,E-46100 BURJASSOT,SPAIN. NR 33 TC 14 Z9 14 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 468 EP 476 DI 10.1103/PhysRevC.44.468 PG 9 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300054 ER PT J AU RAY, A SHAPIRA, D DELCAMPO, JG KIM, HJ BECK, C DJERROUD, B HEUSCH, B BLUMENTHAL, D SHIVAKUMAR, B AF RAY, A SHAPIRA, D DELCAMPO, JG KIM, HJ BECK, C DJERROUD, B HEUSCH, B BLUMENTHAL, D SHIVAKUMAR, B TI COMPOUND NUCLEUS ORIGIN OF BACK-ANGLE YIELDS IN THE P-31+O-16 AND CL-35+C-12 REACTIONS SO PHYSICAL REVIEW C LA English DT Note ID CROSS-SECTIONS; FUSION; DEPENDENCE; FISSION; NI-56 AB The back-angle yields of the oxygen and carbon particles from the P-31 + O-16 reaction have been measured at E(lab)(P-31) = 135.6 MeV by using reverse kinematics. Comparison with similar data for the Cl-35 + C-12 reaction forming the same compound nucleus at the same excitation energy and with a very similar spin distribution shows very small entrance-channel dependence of back-angle yields. These results are in contrast to a similar study of the reactions Si-28 + C-12 and Mg-24 + O-16. It is evident that the oxygen and carbon yields from the P-31 + O-16 and Cl-35 + C-12 reactions have a predominantly compound nucleus origin in contrast to those from the Si-28 + C-12 and Mg-24 + O-16 reactions. Possible connection of this nonequilibrium entrance channel dependence with the presence of nuclear molecular resonances is discussed. C1 UNIV LOUIS PASTEUR,CTR RECH NUCL,F-67037 STRASBOURG,FRANCE. YALE UNIV,WRIGHT NUCL STRUCT LAB,NEW HAVEN,CT 06511. RP RAY, A (reprint author), OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831, USA. NR 20 TC 30 Z9 30 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 514 EP 517 DI 10.1103/PhysRevC.44.514 PG 4 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300060 ER PT J AU RAMAN, S FERNANDEZBACA, JA MOON, RM LYNN, JE AF RAMAN, S FERNANDEZBACA, JA MOON, RM LYNN, JE TI THERMAL-NEUTRON SCATTERING LENGTH AND CAPTURE BY CA-46 SO PHYSICAL REVIEW C LA English DT Note ID ISOTOPES AB We have deduced the coherent scattering amplitude of 46Ca as 3.55 +/- 0.21 fm by measuring the neutron-diffraction patterns of calcite enriched to 32% in 46Ca. We have employed this value in calculating the direct-capture cross sections of the primary electric-dipole gamma-transitions in 47Ca using optical-model potentials with physically realistic parameters. The calculated cross sections agree reasonably well with measurements showing that thermal-neutron capture by 46Ca is controlled largely by a simple direct mechanism. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP RAMAN, S (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Fernandez-Baca, Jaime/C-3984-2014 OI Fernandez-Baca, Jaime/0000-0001-9080-5096 NR 7 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 518 EP 519 DI 10.1103/PhysRevC.44.518 PG 2 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300061 ER PT J AU CASTEN, RF ZHANG, JY LIAO, BC AF CASTEN, RF ZHANG, JY LIAO, BC TI AVERAGE RESONANCE CAPTURE STUDY OF TE-124 SO PHYSICAL REVIEW C LA English DT Note ID TELLURIUM ISOTOPES; NUCLEAR-STRUCTURE; INTRUDER STATES; TRANSITIONS; MODEL AB An average resonance capture study of Te-124 was carried out by bombarding samples of Te-123 with 2- and 24-keV neutron beams. The complete set of 0+, 1+, 2+ states discloed by the experiment is consistent with the data of Robinson, Hamilton, and Snelling, demonstrating that there are no undetected states of these spins (especially 0+ states) below about 2500 keV. In particular, proposed 0+ levels at 1156 and 1290 keV are ruled out. This impacts various attempted interpretations in terms of intruder states, U(5), and O(6) symmetries. C1 CHINESE CTR ADV SCI & TECHNOL,CTR THEORET PHYS,WORLD LAB,BEIJING,PEOPLES R CHINA. INST MODERN PHYS,LANZHOU,PEOPLES R CHINA. JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. UNIV COLOGNE,INST KERNPHYS,W-5000 COLOGNE 41,GERMANY. RP CASTEN, RF (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 20 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 523 EP 526 DI 10.1103/PhysRevC.44.523 PG 4 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300063 ER PT J AU CHEN, JQ FENG, DH GUIDRY, MW WU, CL AF CHEN, JQ FENG, DH GUIDRY, MW WU, CL TI COMPARISON OF REALISTIC AND SYMMETRY-DETERMINED S AND D PAIRS FOR GD-156 - COMMENT SO PHYSICAL REVIEW C LA English DT Note ID NUCLEI; MODEL C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37990. OAK RIDGE NATL LAB,JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. RP CHEN, JQ (reprint author), DREXEL UNIV,DEPT PHYS & ATMOSPHER SCI,PHILADELPHIA,PA 19104, USA. NR 14 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP 559 EP 561 DI 10.1103/PhysRevC.44.559 PG 3 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300074 ER PT J AU GEHRING, JC BACK, BB BETTS, RR FERNANDEZ, PB HENDERSON, DJ NAGAME, Y AF GEHRING, JC BACK, BB BETTS, RR FERNANDEZ, PB HENDERSON, DJ NAGAME, Y TI PROTON-INDUCED FISSION OF U-238 AT EXTREME SUBBARRIER ENERGIES SO PHYSICAL REVIEW C LA English DT Note ID CROSS-SECTIONS AB Cross sections for proton-induced fission of U-238 have been measured at seven proton energies ranging from 3.0 to 4.45 MeV using a kinematic coincidence technique, and an upper limit established at an energy of 2.5 MeV. Contrary to recent findings of Ajitanand et al. [Phys. Rev. Lett. 58, 1520 (1987)], the present work indicates that the fission cross section decreases as expected at extreme sub-barrier energies down to a level of congruent-to 20 pb at 3 MeV. C1 UNIV CHICAGO,CHICAGO,IL 60637. RP GEHRING, JC (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 7 TC 3 Z9 3 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUL PY 1991 VL 44 IS 1 BP R1 EP R4 DI 10.1103/PhysRevC.44.R1 PG 4 WC Physics, Nuclear SC Physics GA FV183 UT WOS:A1991FV18300001 ER PT J AU DAWSON, S HABER, HE AF DAWSON, S HABER, HE TI HEAVY-FERMION EFFECTS IN E+E--]ZH AND Z-]H-UPSILON-UPSILON-BAR- SO PHYSICAL REVIEW D LA English DT Article ID RADIATIVE-CORRECTIONS; WEAK INTERACTIONS; HIGGS PRODUCTION; HIGH-ENERGY AB We consider the effects of the one-loop radiative corrections due to virtual heavy fermions on the process e+e- --> ZH and on the related process Z --> HvvBAR. We show how to compute the one-loop corrections for asymptotically large fermion masses in a very simple manner, using the equivalence theorem where the on-shell Z is replaced by the corresponding Goldstone scalar. Since heavy fermions do not decouple from low-energy phenomena involving the production of external Higgs bosons, the corrections lead to a significant reduction in the rate if there is a heavy fourth generation of quarks and/or leptons. C1 UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106. UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064. RP DAWSON, S (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 19 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 53 EP 59 DI 10.1103/PhysRevD.44.53 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700009 ER PT J AU BAUR, U GLOVER, EWN AF BAUR, U GLOVER, EWN TI OBSERVABILITY OF A HEAVY HIGGS BOSON AT HADRON SUPERCOLLIDERS SO PHYSICAL REVIEW D LA English DT Article ID PAIR PRODUCTION; VECTOR BOSON; FERMILAB TEVATRON; Z0 DECAY; GLUON FUSION; SEARCH; MASS; E+E; COLLISIONS; WIDTH AB We present a coherent analysis of Higgs-boson production in the channels pp --> ZZX --> l+l-l'+l'-X (l,l' = e, mu) and pp --> ZZX --> l+l-nu-nu-XBAR (nu = nu-e, nu-mu, nu-tau) for m(H) greater-than-or-equal-to 600 GeV at hadron supercolliders, using the exact matrix elements for gg --> ZZ and qq --> qqZZ. The importance of a complete understanding of the shape of the perturbative pp --> ZZX background from nonresonant diagrams is emphasized. We find that for the CERN Large Hadron Collider (LHC) to have a Higgs-boson discovery potential comparable to that of the Superconducting Super Collider (SSC) requires at least a factor of 10 times more integrated luminosity. In particular, assuming an integrated luminosity of 10(4) pb-1 and perfect lepton identification efficiency, the LHC (SSC) can identify Higgs bosons as resonances with mass up to 600 (800) GeV in pp --> ZZX --> l+l-l'+l'-X. To extend the discovery range of the LHC to m(H) = 800 GeV in this channel requires an integrated luminosity of at least 10(5) pb-1. For m(H) > 800 GeV, a clear resonance structure is missing; however, one can still discriminate between a heavy Higgs boson with m(H) approximately 1 TeV and a light Higgs boson (m(H) less-than-or-similar-to 2M(z)) at the SSC. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP BAUR, U (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. RI Glover, Edward/A-4597-2012 OI Glover, Edward/0000-0002-0173-4175 NR 53 TC 21 Z9 21 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 99 EP 109 DI 10.1103/PhysRevD.44.99 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700014 ER PT J AU RIZZO, TG AF RIZZO, TG TI SINGLE-LEPTOQUARK PRODUCTION IN Z-DECAYS SO PHYSICAL REVIEW D LA English DT Article ID COLLIDERS AB The possibility of observing leptoquarks which manifest themselves as rare decay modes of the Z is examined in a wide variety of models. At a Z factory, with greater-than-or-similar-to 10(7) Z's, a significant signal for the production and decay of such particles can be obtained for masses as large as congruent-to 80 GeV in some models. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP RIZZO, TG (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. NR 15 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 186 EP 190 DI 10.1103/PhysRevD.44.186 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700022 ER PT J AU RIZZO, TG AF RIZZO, TG TI Z-Z' MIXING AND BOUNDS ON NEW NEUTRAL GAUGE BOSONS FROM SN-1987A DATA SO PHYSICAL REVIEW D LA English DT Article ID RADIATIVE-CORRECTIONS; E6 MODELS; TOP QUARK; MASSES; CONSTRAINTS; LIMIT AB Recently obtained bounds on the mass of the new neutral gauge bosons in E6 models using data from SN 1987A are reexamined and improved by the incorporation of Z-Z' mixing effects and radiative corrections. The sensitivity of these bounds to the various model parameters, e.g., the ratio of Higgs vacuum expectation values (tan-beta), is examined and, in some models, the value of tan-beta can change the resulting Z' mass bound by more than 400-600 GeV. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP RIZZO, TG (reprint author), UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706, USA. NR 31 TC 15 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 202 EP 206 DI 10.1103/PhysRevD.44.202 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700024 ER PT J AU BAER, H TATA, X WOODSIDE, J AF BAER, H TATA, X WOODSIDE, J TI UPDATE OF THE EFFECT OF CASCADE DECAYS ON THE FERMILAB TEVATRON GLUINO AND SQUARK MASS BOUNDS SO PHYSICAL REVIEW D LA English DT Article ID PPBAR COLLIDER; SUPERSYMMETRIC PARTICLES; SEARCH; SUPERCOLLIDERS; SUPERGRAVITY; PHYSICS; LIMITS; LEP AB We present an improved and updated analysis of the effect of cascade decays on the gluino and squark mass bounds recently obtained by the Collider Detector at Fermilab (CDF) Collaboration under the assumption that gluinos and squarks only decay to the lightest supersymmetric particle. We delineate regions of parameter space of the minimal model excluded by our cascade analysis, and combine these regions with regions excluded by recent CERN LEP data. We find that the gluino bound is diminished by 10-30 GeV from its CDF value depending on model parameters. We show that a gluino as light as 135 GeV is allowed, in contrast with the absolute lower bound of 150 GeV obtained by the CDF Collaboration. Corresponding bounds on the squark mass are reduced by typically 15-20 GeV, unless the lightest supersymmetric particle is very heavy. C1 UNIV HAWAII,DEPT PHYS & ASTRON,HONOLULU,HI 96822. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP BAER, H (reprint author), FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306, USA. NR 33 TC 42 Z9 42 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 207 EP 211 DI 10.1103/PhysRevD.44.207 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700025 ER PT J AU RAJPOOT, S AF RAJPOOT, S TI MODEL WITH CALCULABLE DIRAC NEUTRINO MASSES SO PHYSICAL REVIEW D LA English DT Article ID SEE-SAW MASSES; LEPTONS; QUARKS AB An electroweak model based on the gauge group SU(2)L x U(1)R is presented in which neutrinos are massless at the tree level due to a discrete symmetry and acquire tiny finite masses at the one-loop level due to the exchange of two charged Higgs singlets (generalized Zee mechanism) each carrying two units of lepton number. The anomalies are canceled by adding vectorlike singlet fermions. These fermions are also responsible for giving masses to the conventional charged quarks and leptons by the seesaw mechanism. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP RAJPOOT, S (reprint author), CALIF STATE UNIV LONG BEACH,DEPT METEOROL,LONG BEACH,CA 90840, USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 225 EP 228 DI 10.1103/PhysRevD.44.225 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700028 ER PT J AU CHUNG, PL COESTER, F AF CHUNG, PL COESTER, F TI RELATIVISTIC CONSTITUENT-QUARK MODEL OF NUCLEON FORM-FACTORS SO PHYSICAL REVIEW D LA English DT Article ID LIGHT-FRONT DYNAMICS; ELECTRON-DEUTERON SCATTERING; INFINITE-MOMENTUM FRAME; EXCLUSIVE PROCESSES; QUANTUM CHROMODYNAMICS; HYPERFINE INTERACTIONS; STATIC PROPERTIES; BARYONS; (GEV/C)2; PROTON AB We explore the electromagnetic properties of relativistic constituent-quark models of the proton and neutron, in particular their dependence on the constituent-quark mass and the confinement scale. Relativistic effects are never negligible in any model which fits the charge radius of the proton. For a fixed charge radius the confinement scale decreases with decreasing quark masses. Nonvanishing Pauli moments of the constituent quarks are needed to fit the magnetic moments for any value of the quark mass and confinement scale. It is possible to describe existing form-factor data at least up to momentum transfers Q2 = 6 GeV2 with quark masses significantly smaller than the conventional nonrelativistic choice of about one-third of the nucleon mass. RP CHUNG, PL (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 58 TC 133 Z9 133 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 229 EP 241 DI 10.1103/PhysRevD.44.229 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700029 ER PT J AU WONG, CY WANG, RC SHIH, CC AF WONG, CY WANG, RC SHIH, CC TI STUDY OF PARTICLE-PRODUCTION USING 2-DIMENSIONAL BOSONIZED QED SO PHYSICAL REVIEW D LA English DT Article ID SOFT GLUON INTERFERENCE; JET FRAGMENTATION; MONTE-CARLO; E+E ANNIHILATION; SCHWINGER MODEL; LIGHT-CONE; QCD JETS; COLLISIONS AB In order to extract important features of the process of particle production, we study the dynamics of the process by making use of bosonized quantum electrodynamics in one space and one time dimension. We obtain the rapidity distribution of produced particles, the fragmentation function, and the dynamics of the boson field when a positive charge and a negative charge are separated at a finite energy. Our results are generalizations of those of Casher, Kogut, and Susskind and agree with their results in the high-energy limit. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. UNIV SCI & TECHNOL,CTR ASTROPHYS,HEFEI,PEOPLES R CHINA. RP WONG, CY (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 34 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP 257 EP 262 DI 10.1103/PhysRevD.44.257 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700032 ER PT J AU HEINSON, AP HORVATH, J MATHIAZHAGAN, C MOLZON, WR ARISAKA, K COUSINS, RD KAARSBERG, T KONIGSBERG, J RUBIN, P SLATER, WE WAGNER, DL KINNISON, WW LEE, DM MCKEE, RJ MILNER, EC SANDERS, GH ZIOCK, HJ KNIBBE, P URHEIM, J BIERY, KA DIWAN, MV IRWIN, GM LANG, K MARGULIES, J OUIMETTE, DA SCHWARTZ, A WOJCICKI, SG AUERBACH, LB BELZ, J BUCHHOLZ, P HIGHLAND, VL MCFARLANE, WK SIVERTZ, M RITCHIE, JL YAMASHITA, A CHAPMAN, MD ECKHAUSE, M GINKEL, JF HANCOCK, AD KANE, JR KENNEY, CJ KUANG, Y VULCAN, WF WELSH, RE WHYLEY, RJ WINTER, RG AF HEINSON, AP HORVATH, J MATHIAZHAGAN, C MOLZON, WR ARISAKA, K COUSINS, RD KAARSBERG, T KONIGSBERG, J RUBIN, P SLATER, WE WAGNER, DL KINNISON, WW LEE, DM MCKEE, RJ MILNER, EC SANDERS, GH ZIOCK, HJ KNIBBE, P URHEIM, J BIERY, KA DIWAN, MV IRWIN, GM LANG, K MARGULIES, J OUIMETTE, DA SCHWARTZ, A WOJCICKI, SG AUERBACH, LB BELZ, J BUCHHOLZ, P HIGHLAND, VL MCFARLANE, WK SIVERTZ, M RITCHIE, JL YAMASHITA, A CHAPMAN, MD ECKHAUSE, M GINKEL, JF HANCOCK, AD KANE, JR KENNEY, CJ KUANG, Y VULCAN, WF WELSH, RE WHYLEY, RJ WINTER, RG TI HIGHER-STATISTICS MEASUREMENT OF THE BRANCHING RATIO FOR THE DECAY KL0-]MU-MU SO PHYSICAL REVIEW D LA English DT Note ID MIXING ANGLES; TOP MASS; KL->MU-MU-BAR; TUBES AB With a significant increase in experimental sensitivity, we have observed an additional 281 K(L)0 --> mu-mu events after a background subtraction of 19 +/- 6 events. Normalizing this sample to the simultaneous observation of the decay K(L)0 --> pi+ pi-, we obtain the branching ratio B(K(L)0 --> mu-mu) = [7.6 +/- 0.5(stat) +/- 0.4(syst)] x 10(-9). Combining these data with our previously published sample containing 87 events yields B(K(L)0 --> mu-mu) = (7.0 +/- 0.5) x 10(-9). C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV PENN,PHILADELPHIA,PA 19104. STANFORD UNIV,STANFORD,CA 94309. TEMPLE UNIV,PHILADELPHIA,PA 19122. UNIV TEXAS,AUSTIN,TX 78712. COLL WILLIAM & MARY,WILLIAMSBURG,VA 23185. RP HEINSON, AP (reprint author), UNIV CALIF IRVINE,IRVINE,CA 92717, USA. NR 26 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP R1 EP R5 DI 10.1103/PhysRevD.44.R1 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700001 ER PT J AU KRAKAUER, DA TALAGA, RL ALLEN, RC CHEN, HH HAUSAMMANN, R JOHNSON, WA LEE, WP LU, XQ MAHLER, HJ WANG, KC YAO, H BOWLES, TJ BURMAN, RL CARLINI, RD COCHRAN, DRF DOE, PJ FRANK, JS POTTER, ME PIASETZKY, E SANDBERG, VD AF KRAKAUER, DA TALAGA, RL ALLEN, RC CHEN, HH HAUSAMMANN, R JOHNSON, WA LEE, WP LU, XQ MAHLER, HJ WANG, KC YAO, H BOWLES, TJ BURMAN, RL CARLINI, RD COCHRAN, DRF DOE, PJ FRANK, JS POTTER, ME PIASETZKY, E SANDBERG, VD TI DIRECT EXPERIMENTAL LOWER BOUND ON THE RADIATIVE LIFETIME OF THE MUON NEUTRINO SO PHYSICAL REVIEW D LA English DT Note ID EXPERIMENTAL LIMITS; COINCIDENCE; SCATTERING; SN-1987A; DECAYS; BURST; FLUX AB A sensitive search for nu(mu) and nu-muBAR decay into photons was performed in a high-intensity beam of neutrinos from pi+ and mu+ decay at rest. An upper limit of 68 possible gamma-ray events was established, leading to a lower bound on the radiative lifetime of the muon (anti)neutrino of tau/m-nu-mu greater-than-or-equal-to 15.4 sec/eV (90% C.L.). This result represents more than a factor of 100 improvement over previous direct laboratory searches. C1 UNIV CALIF IRVINE,IRVINE,CA 92717. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. TEL AVIV UNIV,RAYMOND & BEVERLY SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. RP KRAKAUER, DA (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 19 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUL 1 PY 1991 VL 44 IS 1 BP R6 EP R9 DI 10.1103/PhysRevD.44.R6 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU487 UT WOS:A1991FU48700002 ER PT J AU KOLB, EW TURNER, MS AF KOLB, EW TURNER, MS TI ASTROPHYSICS AND COSMOLOGY CONFRONT THE 17-KEV NEUTRINO SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-NEUTRINO; BETA-SPECTRUM; PRIMORDIAL NUCLEOSYNTHESIS; CONSTRAINTS; SEARCH; DECAY; S-35; SN1987A; AXIONS; PARTICLES AB Astrophysical and cosmological arguments constrain the properties of a 17-keV Dirac neutrino. it must have interactions beyond those of the standard electroweak theory to reduce its cosmic abundance by a factor of 200. A predicament arises because the additional helicity states of the neutrino necessary to construct a Dirac mass must have interactions strong enough to evade the astrophysical bound from SN 1987A, but weak enough to avoid violating the bound from primordial nucleosynthesis. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. RP KOLB, EW (reprint author), FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 39 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 1 PY 1991 VL 67 IS 1 BP 5 EP 8 DI 10.1103/PhysRevLett.67.5 PG 4 WC Physics, Multidisciplinary SC Physics GA FU343 UT WOS:A1991FU34300002 ER PT J AU GRISHAM, LR SCOTT, SD GOLDSTON, RJ BELL, MG BELL, R BRETZ, NL BUSH, CE GREK, B HAMMETT, GH HILL, K JOBES, F JOHNSON, D KAYE, S MANSFIELD, D MUELLER, D PARK, HK RAMSEY, A SCHIVELL, J STRATTON, B SYNAKOWSKI, EJ TAYLOR, G TOWNER, HH AF GRISHAM, LR SCOTT, SD GOLDSTON, RJ BELL, MG BELL, R BRETZ, NL BUSH, CE GREK, B HAMMETT, GH HILL, K JOBES, F JOHNSON, D KAYE, S MANSFIELD, D MUELLER, D PARK, HK RAMSEY, A SCHIVELL, J STRATTON, B SYNAKOWSKI, EJ TAYLOR, G TOWNER, HH TI SCALING OF CONFINEMENT WITH MAJOR AND MINOR RADIUS IN THE TOKAMAK FUSION TEST REACTOR SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY CONFINEMENT; HEATED TOKAMAKS; TRANSPORT AB Plasma-size scans have been performed in the Tokamak Fusion Test Reactor to investigate the effect of major and minor radius upon energy confinement in high-recycling plasmas heated by neutral-beam injection. The major radius, minor radius, and aspect ratio were varied over a large range (a = 0.4-0.9 m, R = 2.08-3.2 m, R/a = 2.8-8.0). The energy confinement measured with diamagnetic and kinetic diagnostics scales strongly with major radius, and weakly or negatively with minor radius. RP GRISHAM, LR (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Hammett, Gregory/D-1365-2011 OI Hammett, Gregory/0000-0003-1495-6647 NR 10 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 1 PY 1991 VL 67 IS 1 BP 66 EP 69 DI 10.1103/PhysRevLett.67.66 PG 4 WC Physics, Multidisciplinary SC Physics GA FU343 UT WOS:A1991FU34300018 ER PT J AU BEDROSSIAN, P HOUSTON, JE TSAO, JY CHASON, E PICRAUX, ST AF BEDROSSIAN, P HOUSTON, JE TSAO, JY CHASON, E PICRAUX, ST TI LAYER-BY-LAYER SPUTTERING AND EPITAXY OF SI(100) SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; ION-BOMBARDMENT; SURFACE; OSCILLATIONS; GROWTH; GAAS; PT(111); DEFECTS; MBE AB We report oscillations in diffracted electron intensities during ion bombardment of Si(100) by 200- and 250-eV Xe, both alone and with sequential and simultaneous epitaxy. Analysis of the phase and frequency of the oscillations shows that, to first order, ion bombardment "undoes" previous epitaxy and cancels or partially cancels simultaneous deposition. Surprisingly, the phase relationship of growth and sputtering is both antisymmetric and linear, indicating that the ion-induced oscillations are dominated by simple, vacancy-mediated, layer-by-layer sputtering. RP BEDROSSIAN, P (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 20 TC 67 Z9 67 U1 0 U2 11 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 JUL 1 PY 1991 VL 67 IS 1 BP 124 EP 127 DI 10.1103/PhysRevLett.67.124 PG 4 WC Physics, Multidisciplinary SC Physics GA FU343 UT WOS:A1991FU34300033 ER PT J AU RECHESTER, AB WHITE, RB AF RECHESTER, AB WHITE, RB TI SYMBOLIC KINETIC-EQUATION FOR A CHAOTIC ATTRACTOR SO PHYSICS LETTERS A LA English DT Article AB We used symbolic dynamics to partition into "states" the phase space (coarse graining) of a chaotic attractor. The time evolution equation for a distribution function has been discretized and a closed system of coupled linear equations with constant coefficients has been obtained. We calculated the invariant distribution function and correlation function using these equations and found an excellent agreement with direct time average computations. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544. RP RECHESTER, AB (reprint author), MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139, USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 10 TC 25 Z9 29 U1 0 U2 3 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 JUL 1 PY 1991 VL 156 IS 7-8 BP 419 EP 424 DI 10.1016/0375-9601(91)90720-S PG 6 WC Physics, Multidisciplinary SC Physics GA FV817 UT WOS:A1991FV81700012 ER PT J AU COOPER, F SHEPARD, HK SIMMONS, LM AF COOPER, F SHEPARD, HK SIMMONS, LM TI VARIATIONAL APPROXIMATIONS TO THE NONLINEAR SCHRODINGER-EQUATION SO PHYSICS LETTERS A LA English DT Article ID QUANTUM-FIELD THEORY; EXPANSION AB We study analytically the family of nonlinear Schrodinger equations (NLSE) i partial-psi/partial t + partial 2 psi/partial-chi-2 + g(psiBAR-psi)kappa-psi = 0 for arbitrary values of the nonlinearity parameter-kappa using two variational strategies based on two different perturbation expansions of the equation - the delta-expansion (DE) (which expands in the nonlinearity) and the linear delta expansion (LDE) (which expands about an optimal linear term). For simplicity we discuss solutions to the initial value problem for which psi(chi, t = 0) = C-delta(chi). For the LDE the variational calculation gives the exact analytic solution to the NLSE for arbitrary-kappa for this initial data. The answer has different structure for kappa < 1, kappa = 1 and kappa > 1. For the delta-expansion the variational calculation gives a sequence of approximations to the solution valid for kappa < 1. C1 UNIV NEW HAMPSHIRE,DEPT PHYS,DURHAM,NH 03824. SANTA FE INST,SANTA FE,NM 87501. RP COOPER, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,T-8,MS B285,LOS ALAMOS,NM 87545, USA. NR 7 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUL 1 PY 1991 VL 156 IS 7-8 BP 436 EP 440 DI 10.1016/0375-9601(91)90723-L PG 5 WC Physics, Multidisciplinary SC Physics GA FV817 UT WOS:A1991FV81700015 ER PT J AU ROTMAN, D AF ROTMAN, D TI SHOCK-WAVE EFFECTS ON A TURBULENT-FLOW SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID HOMOGENEOUS TURBULENCE AB A parametric study is done to investigate the change in a turbulent flow field caused by the passage of a shock wave. Two parameters are studied: the initial turbulent kinetic energy and the shock wave strength or density jump. A random or turbulent flow field is initiated within a two-dimensional box. Euler's equations are then solved using a second-order accurate Godunov shock capturing method to calculate the change in turbulent structure and flow field parameters caused by the passage of a shock wave through the turbulent field. Two fields were analyzed, a random density field and a random velocity field. The passage of a shock through the random density field caused density and pressure variations that compare very well with experiments. Results of the shock passage through the random velocity field show that the shock causes an amplification in the turbulent kinetic energy of about 2 on a per unit mass basis. Furthermore, the length scale of the turbulent field behind the shock is smaller than that in front of the shock. Energy weighted wave numbers increase by as much as 30%. This change in length scales seems to be in disagreement with some experiments which seem to show larger time scales and larger length scales behind a shock, but in agreement with another experiment. For both results, fields containing strong shocks or weak turbulent fields yield the largest change in flow parameters. The shock wave is also affected by the turbulent field. Increasing the initial turbulent kinetic energy caused a straight shock wave to evolve into a shock containing curves and wrinkles of a size similar to the length scale of the unshocked turbulent field. These curves and wrinkles can lead to the generation of additional flow field oscillations. RP UNIV CALIF LAWRENCE LIVERMORE NATL LAB, MAIL STOP L-262, LIVERMORE, CA 94550 USA. NR 28 TC 55 Z9 56 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD JUL PY 1991 VL 3 IS 7 BP 1792 EP 1806 DI 10.1063/1.857960 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GM594 UT WOS:A1991GM59400015 ER PT J AU KERSTEIN, AR AF KERSTEIN, AR TI SCALING PROPERTIES OF THE VISCOUS-CONVECTIVE SCALAR SPECTRAL SUBRANGE IN TURBULENT JETS SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Note AB A recent analysis by Dimotakis and Miller [Phys. Fluids A 2, 1919 (1990)] of the power spectrum of a diffusive scalar in turbulent flow identified a difficulty with the k-1 viscous-convective scaling in the limit of very large Schmidt number for finite-Reynolds-number flows with bounded scalar fluctuations. Here, a modified scaling of the form k-1-p is derived for the self-similar round jet, where p approximately Re-1/2 for Re >> 1. RP KERSTEIN, AR (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 4 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 0899-8213 J9 PHYS FLUIDS A-FLUID PD JUL PY 1991 VL 3 IS 7 BP 1832 EP 1835 DI 10.1063/1.857911 PG 4 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA GM594 UT WOS:A1991GM59400021 ER PT J AU DIMITS, AM LEE, WW AF DIMITS, AM LEE, WW TI NONLINEAR MECHANISMS FOR DRIFT WAVE SATURATION AND INDUCED PARTICLE-TRANSPORT SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID TURBULENCE; PLASMA; INSTABILITIES; SIMULATION; TOKAMAKS; EDGE AB In previous studies, it was shown that, in the nonlinearly saturated phase of the evolution of drift instabilities in gyrokinetic particle simulations, the saturation levels and especially the particle fluxes are significantly less than predicted by quasilinear theory, and have an unexpected dependence on collisionality. In this paper, a theory is developed that explains these phenomena. The key features of the theory are as follows: The saturation level is determined by a balance between the steady-state electron and ion fluxes. The ion flux is small for levels of the potential below an EXB-trapping threshold and increases sharply once this threshold is crossed. Because of the presence of resonant electrons, the electron flux has a much smoother dependence on the potential. In the 2 1/2-dimensional ("pseudo-3-D") geometry, the electrons are accelerated away from the resonance as they diffuse spatially, resulting in an inhibition of their diffusion, and thereby reducing the values of the potential and flux at which the fluxes can balance. Collisions and three-dimensional effects can repopulate the resonance thereby increasing the value of the particle flux. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP DIMITS, AM (reprint author), UNIV MARYLAND,PLASMA RES LAB,COLLEGE PK,MD 20742, USA. NR 26 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 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUL PY 1991 VL 3 IS 7 BP 1557 EP 1569 DI 10.1063/1.859674 PG 13 WC Physics, Fluids & Plasmas SC Physics GA FU141 UT WOS:A1991FU14100006 ER PT J AU WALLACE, JM EPPERLEIN, EM AF WALLACE, JM EPPERLEIN, EM TI WEIBEL INSTABILITY WITH CONSTANT DRIVING SOURCE SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID ELECTROMAGNETIC PLASMA SIMULATION; 2 DIMENSIONS; MODELS AB A method has been developed for performing numerical particle-in-cell simulations of the Weibel instability in which the driving anisotropy is held constant. With the method, the instability is computed to grow to saturation in a well-behaved manner. Initially, growth is in close agreement with the predictions of linear theory. Subsequently, the growth rate falls below linear-theory predictions as magnetic fields grow to substantial levels. And finally, the instability reaches saturation, after which a steady state is established. A single mode comes to dominate the magnetic field at late times in the simulations. This is the mode identified in linear theory as the most rapidly growing. The method has been employed to investigate the importance of the Weibel instability in laser-produced plasmas. It is found that, because of saturation, the fields do not grow sufficiently to affect heat flow (omega-c-tau < 1) in the overdense plasma. In the near-critical underdense plasma, the fields would have, at most, marginal influence for shorter wavelength irradiation (lambda-L less-than-or-equal-to 0.25-mu-m) but possibly substantial influence at longer wavelengths (lambda-L greater-than-or-equal-to 1-mu-m). C1 UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14623. RP WALLACE, JM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 22 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUL PY 1991 VL 3 IS 7 BP 1579 EP 1586 DI 10.1063/1.859677 PG 8 WC Physics, Fluids & Plasmas SC Physics GA FU141 UT WOS:A1991FU14100009 ER PT J AU YOSHIKAWA, S AF YOSHIKAWA, S TI TEMPERATURE DISTRIBUTION OF A TOKAMAK WITH A CONSTANT HEAT-CONDUCTIVITY SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article AB An analytical expression of the detached plasma radius in an Ohmically heated tokamak plasma was obtained. The assumption was made that the (anomalous) heat conductivity is constant and independent of minor radius r. The resultant nonlinear differential equation has a universal solution for the plasma temperature as a function of r. The shape is very similar to the so-called profile consistency model. As the average plasma density increases, the tokamak plasma, which is first attached to either the limiter or divertor, detaches itself from the limiter and forms a toroidal plasma whose boundary is clearly marked by a radiative boundary layer where the power input to the plasma is radiated away. As the plasma density increases, the radius of the plasma shrinks until the surface safety factor becomes less than approximately 2, whereupon the plasma disruption starts. The density limit calculated by this model agrees with the experimental observation. RP YOSHIKAWA, S (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 11 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUL PY 1991 VL 3 IS 7 BP 1634 EP 1637 DI 10.1063/1.859682 PG 4 WC Physics, Fluids & Plasmas SC Physics GA FU141 UT WOS:A1991FU14100014 ER PT J AU ENGLAND, AC BELL, GL FOWLER, RH GLOWIENKA, JC HARRIS, JH LEE, DK MURAKAMI, M NEILSON, GH RASMUSSEN, DA ROME, JA SALTMARSH, MJ WILGEN, JB AF ENGLAND, AC BELL, GL FOWLER, RH GLOWIENKA, JC HARRIS, JH LEE, DK MURAKAMI, M NEILSON, GH RASMUSSEN, DA ROME, JA SALTMARSH, MJ WILGEN, JB TI RUNAWAY ELECTRON STUDIES IN THE ATF TORSATRON SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAGNETIC-FIELD; CROSS-SECTIONS AB Runaway electron formation and confinement occur readily in pulsed torsatrons and heliotrons because of the high loop voltages during initiation and termination of the helical and vertical fields ("field ramping") and the inherently good containment of the electrons on the flux surfaces in the vacuum fields. This has been confirmed for the Advanced Toroidal Facility (AFT) [Fusion Technol. 10, 179 (1986)] and other stellarators by orbit calculations. Since runaway electrons can cause an unacceptable level of hard x rays near the machine, a runaway electron suppression system was incorporated in ATF. The main component of the system is a movable paddle, which is normally left in the center of the plasma chamber during the field ramps. This device, in conjunction with programmed vertical field ramping, which reduces the volume of good flux surfaces, has proved to be very effective in reducing the runaway electron population. Measurements of hard x rays from ATF have shown that the runaway electrons are produced primarily during the field ramping but that there is usually also a small steady-state runaway electron component during the "flat-top" portion of the fields. The paddle is the main source of the hard x radiation (thick-target bremsstrahlung). There is evidence that some of the runaway electrons may be confined to islands. The maximum x-ray energy found by pulse height analysis is approximately 12-15 MeV. The mean energy appears to be a few million electron volts. There is a noticeable forward peaking of the bremsstrahlung from the paddle. The limiters do not appear to be major sources of x rays. C1 AUBURN UNIV,AUBURN,AL 36849. RP ENGLAND, AC (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 40 TC 5 Z9 5 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUL PY 1991 VL 3 IS 7 BP 1671 EP 1686 DI 10.1063/1.859687 PG 16 WC Physics, Fluids & Plasmas SC Physics GA FU141 UT WOS:A1991FU14100019 ER PT J AU WEBER, PG INGRAHAM, JC ELLIS, RF WURDEN, GA MUNSON, CP DOWNING, JN AF WEBER, PG INGRAHAM, JC ELLIS, RF WURDEN, GA MUNSON, CP DOWNING, JN TI EFFECTS OF LIMITERS ON REVERSED-FIELD PINCH CONFINEMENT SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PLASMA; ZT-40M AB This paper documents the effects on confinement of introducing discrete limiters into the edge plasma of the ZT-40M reversed-field pinch (RFP) [Fusion Technol. 8, 1571 (1985)]. RFP confinement is not significantly degraded by appropriately designed single limiters inserted to a sufficient depth for effective local vacuum vessel wall protection. Inserting limiters too deeply into the plasma results in excess limiter heating, and a consequent increase in the impurity content of the plasma. Under these conditions the plasma loop voltage increases. The heating of the limiters is observed to be asymmetric, with the majority of the heat flux in ZT-40M being attributable to suprathermal electrons [T(supra) approximately 2-3 X T(e) (0)] reaching the edge moving almost unidirectionally along magnetic-field lines. C1 UNIV MARYLAND,COLLEGE PK,MD 20742. RP WEBER, PG (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Wurden, Glen/A-1921-2017 OI Wurden, Glen/0000-0003-2991-1484 NR 19 TC 3 Z9 3 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 JUL PY 1991 VL 3 IS 7 BP 1701 EP 1707 DI 10.1063/1.859689 PG 7 WC Physics, Fluids & Plasmas SC Physics GA FU141 UT WOS:A1991FU14100021 ER PT J AU NIETO, MM GOLDMAN, T AF NIETO, MM GOLDMAN, T TI THE ARGUMENTS AGAINST ANTIGRAVITY AND THE GRAVITATIONAL ACCELERATION OF ANTIMATTER SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID INVERSE-SQUARE LAW; INTERMEDIATE-RANGE FORCES; NON-NEWTONIAN GRAVITY; COMPOSITION-DEPENDENT FORCE; EQUIVALENCE PRINCIPLE EXPERIMENT; HIGHER-DIMENSIONAL THEORIES; SOURCE EOTVOS EXPERIMENT; GREENLAND ICE CAP; KO-KBARO SYSTEM; 5TH FORCE AB In the 1950's interest arose in the science-fiction idea of "antigravity". This concept was a speculation that matter and antimatter would repel each other in ordinary tensor (Einsteinian) gravity. (This was reminiscent of the Coulomb interaction between like charges.) Three types of arguments were raised to disprove "antigravity": (i) violation of conservation of energy. (ii) violation of the principle of equivalence, (iii) anomalous regeneration of K(S) mesons, all of which were unseen. Unfortunately, in the physics folklore these arguments came to be interpreted as ruling out any difference in the gravitational interaction of matter and antimatter to the earth, not just ruling out this "antigravity." After reviewing the history behind the concept of antigravity, we discuss modern theoretical ideas and experiments which are relevant to the possibility that there exist static, non-Newtonian components of gravity. We then consider the arguments against antigravity, pointing out their regimes of applicability and inapplicability to modern quantum theories of gravity. We specifically show that, if these arguments are applied to the ongoing experiment to measure the gravitational acceleration of the antiproton, they do not rule out a large anomalous gravitational response for the antiproton. The antiproton gravity experiment is one of five types of experiments that we consider to be the most critical in testing for finite but long-range, non-Newtonian and non-Einsteinian gravity. We discuss how all five are related to each other and how their completion would improve our knowledge of gravitational forces. RP NIETO, MM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. NR 428 TC 124 Z9 124 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD JUL PY 1991 VL 205 IS 5 BP 221 EP 281 DI 10.1016/0370-1573(91)90138-C PG 61 WC Physics, Multidisciplinary SC Physics GA GA074 UT WOS:A1991GA07400001 ER PT J AU TAYLOR, CB GREEN, PJ AF TAYLOR, CB GREEN, PJ TI GENES WITH HOMOLOGY TO FUNGAL AND S-GENE RNASES ARE EXPRESSED IN ARABIDOPSIS-THALIANA SO PLANT PHYSIOLOGY LA English DT Note ID SELF-INCOMPATIBILITY; NICOTIANA-ALATA; SEQUENCE; RIBONUCLEASE AB The only RNase genes that have been cloned from higher plants are those expressed in species that are known to exhibit self-incompatibility, such as the S genes of Nicotiana alata. In this report, we investigated whether the expression of this particular type of RNase gene is restricted to self-incompatible species, or if similar genes are expressed in other plants. Using a polymerase chain reaction approach we have identified a set of three putative RNase genes in the self-compatible plant Arabidopsis thaliana (L.) Heynh. ecotype Columbia. These A. thaliana genes, designated RNS1, RNS2, and RNS3, do not cross-hybridize to each other, and their products are homologous to both the S-gene RNases of N. alata and a set of related fungal enzymes. The A. thaliana RNS1, RNS2, and RNS3 genes encode transcripts of 1.1, 1.3, and 1.1 kilobases, respectively, and of the three genes, RNS2 is the most highly expressed in whole plants. The identification of the RNS genes in a self-compatible species suggests that this class of RNases is of general significance in RNA catabolism in higher plants. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. MICHIGAN STATE UNIV,DEPT BIOCHEM,E LANSING,MI 48824. NR 18 TC 59 Z9 63 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 JUL PY 1991 VL 96 IS 3 BP 980 EP 984 DI 10.1104/pp.96.3.980 PG 5 WC Plant Sciences SC Plant Sciences GA FX725 UT WOS:A1991FX72500047 PM 16668284 ER PT J AU FRANSE, J ROBLEE, JW MODEMANN, K AF FRANSE, J ROBLEE, JW MODEMANN, K TI DYNAMIC CHARACTERISTICS OF THE LAWRENCE-LIVERMORE-NATIONAL-LABORATORY PRECISION ENGINEERING RESEARCH LATHE SO PRECISION ENGINEERING-JOURNAL OF THE AMERICAN SOCIETY FOR PRECISION ENGINEERING LA English DT Article DE DYNAMIC COMPLIANCE; SURFACE QUALITY; CAPSTAN DRIVES; MACHINE TOOL DYNAMICS; PRECISION MACHINE TOOLS; EXPERIMENTAL MECHANICS AB The dynamic characteristics of the Precision Engineering Research Lathe (PERL) have been investigated experimentally, up to a frequency of 1,000 Hz. In successive tests, the exciting force was applied to either the x-slide or the (nonrotating) spindle, and in the x- or z-direction. These are the critical directions for turning operations on this T-base type lathe. Each of these tests was furthermore done with the servo system active and with the servo system off (slides clamped, control loops open). The applied force fluctuations and the resulting relative displacement, between a capacitive probe mounted on the x-slide and the spindle, were measured during the experiments. From these data, the relative dynamic compliances between the tool and the workpiece, in the z- and x-directions, have been determined. The resonant frequencies, modes, and compliances that significantly influence the surface quality of the parts turned on this machine are reported. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 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 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Am. Soc. Precis. Eng. PD JUL PY 1991 VL 13 IS 3 BP 196 EP 202 DI 10.1016/0141-6359(91)90098-4 PG 7 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA GB968 UT WOS:A1991GB96800005 ER PT J AU WILLIAMS, GM CORREA, P BARTSCH, H DIPPLE, A TANNENBAUM, S PECHACEK, T GREENWALD, P CARROLL, K MCKEOWNEYSSEN, G FELTON, J CAMPBELL, CC WATTENBERG, L UPTON, A HAUSEN, HZ HIGGINSON, J RANDERATH, K CONNEY, A AMES, B KROES, R AF WILLIAMS, GM CORREA, P BARTSCH, H DIPPLE, A TANNENBAUM, S PECHACEK, T GREENWALD, P CARROLL, K MCKEOWNEYSSEN, G FELTON, J CAMPBELL, CC WATTENBERG, L UPTON, A HAUSEN, HZ HIGGINSON, J RANDERATH, K CONNEY, A AMES, B KROES, R TI AMERICAN HEALTH FOUNDATIONS 20TH ANNIVERSARY INTERNATIONAL-SYMPOSIUM ON CAUSES AND PREVENTION OF CANCER - DECEMBER 11-12, 1989, NEW-YORK-CITY SO PREVENTIVE MEDICINE LA English DT Editorial Material ID HEMOGLOBIN ADDUCT; VITAMIN-C; CARCINOGENESIS; DNA; SMOKERS; RISK; PAPILLOMAVIRUSES; 4-AMINOBIPHENYL; EXPOSURE; BLADDER C1 LOUISIANA STATE UNIV,BATON ROUGE,LA 70803. INT AGCY RES CANC,F-69372 LYONS,FRANCE. NCI,FREDERICK CANC RES FACIL,FREDERICK,MD 21701. MIT,CAMBRIDGE,MA 02139. UNIV WESTERN ONTARIO,LONDON N6A 3K7,ONTARIO,CANADA. UNIV TORONTO,TORONTO M5S 1A1,ONTARIO,CANADA. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CORNELL UNIV,ITHACA,NY 14853. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. NYU MED CTR,NEW YORK,NY 10016. GERMAN CANC RES CTR,W-6900 HEIDELBERG 1,GERMANY. GEORGETOWN UNIV,MED CTR,WASHINGTON,DC 20007. BAYLOR UNIV,HOUSTON,TX 77030. RUTGERS STATE UNIV,NEW BRUNSWICK,NJ 08903. RP WILLIAMS, GM (reprint author), AMER HLTH FDN,1 DANA RD,VALHALLA,NY 10595, USA. NR 43 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 0091-7435 J9 PREV MED JI Prev. Med. PD JUL PY 1991 VL 20 IS 4 BP 534 EP 547 DI 10.1016/0091-7435(91)90051-5 PG 14 WC Public, Environmental & Occupational Health; Medicine, General & Internal SC Public, Environmental & Occupational Health; General & Internal Medicine GA FV005 UT WOS:A1991FV00500009 PM 1871081 ER PT J AU GODFREY, VL WILKINSON, JE RINCHIK, EM RUSSELL, LB AF GODFREY, VL WILKINSON, JE RINCHIK, EM RUSSELL, LB TI FATAL LYMPHORETICULAR DISEASE IN THE SCURFY (SF) MOUSE REQUIRES T-CELLS THAT MATURE IN A SF THYMIC ENVIRONMENT - POTENTIAL MODEL FOR THYMIC EDUCATION SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE X-LINKED LYMPHORETICULAR DISEASE; BONE-MARROW TRANSPLANTS; THYMIC EDUCATION ID MICE; TOLERANCE AB Characteristic lesions in mice hemi- or homozygous for the X-linked mutation scurfy (sf) include lymphohistiocytic proliferation in the skin and lymphoid organs, Coombs' test-positive anemia, hypergammaglobulinemia, and death by 24 days of age. The role of the thymus in the development of fatal lymphoreticular disease in the scurfy mouse was investigated. Neonatal thymectomy doubles the life span of scurfy mice, moderates the histologic lesions, and prevents anemia, despite the continued presence of high levels of serum IgG. Animals bred to be nude and scurfy (nu/nu; sf/Y) are viable, fertile, and free of scurfy lesions. Bone marrow from scurfy mice can reconstitute lethally irradiated, H-2-compatible animals but does not transmit scurfy disease. We conclude, from these data, that scurfy lesions are mediated by T lymphocytes that mature in an abnormal (sf) thymic environment. C1 UNIV TENNESSEE,COLL VET MED,KNOXVILLE,TN 37901. RP GODFREY, VL (reprint author), OAK RIDGE NATL LAB,DIV BIOL,POB 2009,OAK RIDGE,TN 37831, USA. NR 19 TC 111 Z9 113 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 JUL PY 1991 VL 88 IS 13 BP 5528 EP 5532 DI 10.1073/pnas.88.13.5528 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FU901 UT WOS:A1991FU90100011 PM 2062835 ER PT J AU MASTRANGELO, IA COUREY, AJ WALL, JS JACKSON, SP HOUGH, PVC AF MASTRANGELO, IA COUREY, AJ WALL, JS JACKSON, SP HOUGH, PVC TI DNA LOOPING AND SP1 MULTIMER LINKS - A MECHANISM FOR TRANSCRIPTIONAL SYNERGISM AND ENHANCEMENT SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE TRANSCRIPTION FACTOR-SP1; ENHANCER MECHANISM; SCANNING TRANSMISSION ELECTRON MICROSCOPY ID RNA POLYMERASE-II; MAJOR LATE PROMOTER; 3-DIMENSIONAL STRUCTURE; PROTEIN; BINDING; ACTIVATION; GENE; INITIATION; UPSTREAM; DOMAINS AB Using conventional and scanning transmission electron microscopy, we have examined the physical basis of long-range enhancer effects between distal and proximal elements in a eukaryotic promoter. Specifically, we have studied binding of human transcription factor Sp1 to 10-base-pair G + C-rich elements ("GC boxes") located at -100 and +1700 relative to the RNA start site. It was previously observed that the distantly located site functions in synergism with the promoter-proximal site to strongly activate transcription in vivo. Here we demonstrate that this synergism is likely to be a direct consequence of interactions between remote and local Sp1, the remote Sp1 translocated to the promoter by a DNA loop. Scanning transmission electron microscopy shows that Sp1 initially forms a tetramer and subsequently assembles multiple tetramers stacked in register at the DNA loop juncture. This unexpected finding not only provides the physical basis for loop formation but also defines a biological process leading to strongly increased concentration of activator protein at the promoter. The mechanism may unify the problem of transcriptional activation by removing enhancer action as a separate class of regulatory activity. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024. UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,HOWARD HUGHES MED INST,BERKELEY,CA 94720. RI Dry, Kate/I-2328-2014 NR 43 TC 211 Z9 212 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 JUL PY 1991 VL 88 IS 13 BP 5670 EP 5674 DI 10.1073/pnas.88.13.5670 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FU901 UT WOS:A1991FU90100040 PM 2062845 ER PT J AU ISHIMITSU, T UEHARA, Y IWAI, J SUGIMOTO, T HIRATA, Y MATSUOKA, H SUGIMOTO, T AF ISHIMITSU, T UEHARA, Y IWAI, J SUGIMOTO, T HIRATA, Y MATSUOKA, H SUGIMOTO, T TI VASCULAR EICOSANOID PRODUCTION IN EXPERIMENTAL HYPERTENSIVE RATS WITH DIFFERENT MECHANISMS SO PROSTAGLANDINS LEUKOTRIENES AND ESSENTIAL FATTY ACIDS LA English DT Article ID ENDOTHELIAL-CELLS; ION CHANNELS; THROMBOXANE-A2; SUBSTANCE; PROSTACYCLIN; ARTERIES; RELEASE; WALLS AB This study investigated the release of prostacyclin (PGI2) and thromboxane A2 (TXA2) from the aortic walls of various experimental hypertensive rats, e.g. spontaneously hypertensive rats (SHR), Dahl salt-sensitive (Dahl S) rats, deoxycorticosterone (DOCA)-salt hypertensive rats and renovascular (2-kidney, 1-clip (2K1C) and 1-kidney, 1-clip (1K1C)) hypertensive rats. The PGI2 generation was increased significantly in these hypertensive models, irrespective of the hypertensive mechanisms, when they developed established hypertension. Dahl S rats, having an impaired PGI2 production on a low salt diet, restored PGI2 generating capacity to the control level of Dahl salt-resistant rats when they were fed a high salt diet and developed salt-induced hypertension. On the other hand, the TXA2 generation in the vascular walls was enhanced particularly in rat models for genetic hypertension, and this system was unaltered in the models for secondary hypertension, e.g. DOCA-salt and renovascular hypertension. Thus, it is suggested that the elevation of blood pressure is associated with an increase in vascular PGI2 production, and that the increased vascular TXA2 production is a characteristic feature of genetic hypertension. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. RP ISHIMITSU, T (reprint author), UNIV TOKYO,DEPT INTERNAL MED 2,7-3-1 HONGO,BUNKYO KU,TOKYO 113,JAPAN. NR 22 TC 16 Z9 16 U1 0 U2 0 PU CHURCHILL LIVINGSTONE PI EDINBURGH PA JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH, MIDLOTHIAN, SCOTLAND EH1 3AF SN 0952-3278 J9 PROSTAG LEUKOTR ESS JI Prostaglandins Leukot. Essent. Fatty Acids PD JUL PY 1991 VL 43 IS 3 BP 179 EP 184 DI 10.1016/0952-3278(91)90166-3 PG 6 WC Biochemistry & Molecular Biology; Cell Biology; Endocrinology & Metabolism SC Biochemistry & Molecular Biology; Cell Biology; Endocrinology & Metabolism GA FW637 UT WOS:A1991FW63700007 PM 1871182 ER PT J AU CORNFORTH, MN GOODWIN, EH AF CORNFORTH, MN GOODWIN, EH TI THE DOSE-DEPENDENT FRAGMENTATION OF CHROMATIN IN HUMAN FIBROBLASTS BY 3.5-MEV ALPHA-PARTICLES FROM PU-238 - EXPERIMENTAL AND THEORETICAL CONSIDERATIONS PERTAINING TO SINGLE-TRACK EFFECTS SO RADIATION RESEARCH LA English DT Article ID PREMATURE CHROMOSOME CONDENSATION; PERIPHERAL-BLOOD LYMPHOCYTES; HUMAN INTERPHASE CHROMOSOMES; POTENTIALLY LETHAL DAMAGE; ULTRASOFT X-RAYS; HAMSTER-CELLS; IONIZING-RADIATION; IRRADIATION; BREAKS; ABERRATIONS RP CORNFORTH, MN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,CELLULAR & MOLEC BIOL GRP,LOS ALAMOS,NM 87545, USA. FU NCI NIH HHS [CA45141] NR 43 TC 50 Z9 50 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 JUL PY 1991 VL 127 IS 1 BP 64 EP 74 DI 10.2307/3578090 PG 11 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA FX438 UT WOS:A1991FX43800010 PM 2068273 ER PT J AU NALESSO, GF JACOBSON, AR AF NALESSO, GF JACOBSON, AR TI APPROXIMATE SOLUTIONS AND ERROR-BOUNDS FOR THE WAVE-EQUATION IN A STRATIFIED IONOSPHERE WITH TURNING-POINTS SO RADIO SCIENCE LA English DT Article ID HF RADIO-WAVES; REFLECTION REGION; PATTERN AB In this paper we present a solution of the problem of a plane electromagnetic wave traveling parallel to a constant magnetic field (k parallel-to B0 parallel-to z/\z\) in a horizontally stratified ionosphere. We assume, in particular, that the permittivity of the medium can be decomposed as the sum of an unperturbed and a perturbed part and that the unperturbed term is a smooth function of the height z that can be analytically continued in the complex plane and has furthermore a single simple zero (turning point) in a simply connected region D which includes the interval (alpha, infinity) of the real axis. The method gives approximate solutions valid in the region D and therefore also through the turning point. These solutions are obtained by truncating certain formal (generally divergent) series solutions of the wave equation. Furthermore, a realistic error bound for the remainder term associated with the truncated series is also derived and discussed. This method is successively applied to the case of a linearly varying permittivity of a lossless ionosphere with a superimposed Gaussian perturbing term. The possibility of applying the method when an odd number of turning points are present is also discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & SPACE SCI,ATMOSPHER SCI GRP,LOS ALAMOS,NM 87545. RP NALESSO, GF (reprint author), DIPARTIMENTO ELETTR & INFORMAT,VIA GRADENIGO 6-A,I-35131 PADUA,ITALY. NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1991 VL 26 IS 4 BP 881 EP 890 DI 10.1029/91RS00934 PG 10 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA FZ016 UT WOS:A1991FZ01600007 ER PT J AU BLAKE, GA LAUGHLIN, KB COHEN, RC BUSAROW, KL GWO, DH SCHMUTTENMAER, CA STEYERT, DW SAYKALLY, RJ AF BLAKE, GA LAUGHLIN, KB COHEN, RC BUSAROW, KL GWO, DH SCHMUTTENMAER, CA STEYERT, DW SAYKALLY, RJ TI TUNABLE FAR INFRARED-LASER SPECTROMETERS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Review ID ROTATION-TUNNELING SPECTRUM; PLANAR SUPERSONIC JET; SIDEBAND SPECTROSCOPY; VANDERWAALS BONDS; LABORATORY MEASUREMENT; BENDING VIBRATION; FREE-RADICALS; HCL DIMER; AR-HCL; REGION AB The state of the art in far infrared (FIR) spectroscopy is reviewed. The development of tunable, coherent FIR radiation sources is discussed. Applications of tunable FIR laser spectrometers for measurement of rotational spectra and dipole moments of molecular ions and free radicals, vibration-rotation-tunneling (VRT) spectra of weakly bound complexes, and vibration-rotation spectra of linear carbon clusters are presented. A detailed description of the Berkeley tunable FIR laser spectrometers is presented in the following article. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RI Cohen, Ronald/A-8842-2011 OI Cohen, Ronald/0000-0001-6617-7691 NR 61 TC 69 Z9 69 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1991 VL 62 IS 7 BP 1693 EP 1700 DI 10.1063/1.1142409 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA FU522 UT WOS:A1991FU52200001 ER PT J AU BLAKE, GA LAUGHLIN, KB COHEN, RC BUSAROW, KL GWO, DH SCHMUTTENMAER, CA STEYERT, DW SAYKALLY, RJ AF BLAKE, GA LAUGHLIN, KB COHEN, RC BUSAROW, KL GWO, DH SCHMUTTENMAER, CA STEYERT, DW SAYKALLY, RJ TI THE BERKELEY TUNABLE FAR INFRARED-LASER SPECTROMETERS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID HIGH-POWER OPERATION; OPEN STRUCTURE MIXER; WAVEGUIDE LASER; DIODE MIXERS; SPECTROSCOPY; WAVELENGTHS; GENERATION; SIDEBANDS; DETECTORS; REGION AB A detailed description is presented for a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode. The system has been operated on over 30 laser lines in the range 10-100 cm-1 and exhibits a maximum absorption sensitivity near one part in 10(6). Each laser line can be tuned by +/- 110 GHz with first-order sidebands. Applications of this instrument are detailed in the preceding paper. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RI Cohen, Ronald/A-8842-2011 OI Cohen, Ronald/0000-0001-6617-7691 NR 40 TC 92 Z9 92 U1 1 U2 5 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 JUL PY 1991 VL 62 IS 7 BP 1701 EP 1716 DI 10.1063/1.1142410 PG 16 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA FU522 UT WOS:A1991FU52200002 ER PT J AU ABLES, E BIONTA, RM MILLER, KA OLSEN, HE SKULINA, KM AF ABLES, E BIONTA, RM MILLER, KA OLSEN, HE SKULINA, KM TI A MECHANICAL THICKNESS SCALE FOR OPAQUE PARTS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Note AB A method for measuring the thickness of opaque parts to within 4-mu-m by inserting a small scale into the part or along side has been developed. A combination digital and analog scale is used to determine the length of the scale when viewed from the edge. This scale should be useful for applications where only one surface is exposed during machining or polishing, and where the side is also inaccessible. RP ABLES, E (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 U1 3 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1991 VL 62 IS 7 BP 1867 EP 1868 DI 10.1063/1.1142387 PG 2 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA FU522 UT WOS:A1991FU52200032 ER PT J AU TAYLOR, RE AF TAYLOR, RE TI DEEP INELASTIC-SCATTERING - THE EARLY YEARS SO REVIEWS OF MODERN PHYSICS LA English DT Article RP TAYLOR, RE (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 33 TC 48 Z9 51 U1 0 U2 4 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 JUL PY 1991 VL 63 IS 3 BP 573 EP 595 DI 10.1103/RevModPhys.63.573 PG 23 WC Physics, Multidisciplinary SC Physics GA FX970 UT WOS:A1991FX97000001 ER PT J AU FRIEDMAN, JI KENDALL, HW TAYLOR, RE AF FRIEDMAN, JI KENDALL, HW TAYLOR, RE TI DEEP INELASTIC-SCATTERING - ACKNOWLEDGMENTS SO REVIEWS OF MODERN PHYSICS LA English DT Article C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP FRIEDMAN, JI (reprint author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA. NR 3 TC 5 Z9 5 U1 1 U2 2 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 JUL PY 1991 VL 63 IS 3 BP 629 EP 629 DI 10.1103/RevModPhys.63.629 PG 1 WC Physics, Multidisciplinary SC Physics GA FX970 UT WOS:A1991FX97000004 ER PT J AU HEIFETS, SA KHEIFETS, SA AF HEIFETS, SA KHEIFETS, SA TI COUPLING IMPEDANCE IN MODERN ACCELERATORS SO REVIEWS OF MODERN PHYSICS LA English DT Review ID LONGITUDINAL IMPEDANCE; HIGH-FREQUENCY; BEAM-PIPE; CAVITY; AXIS; COMPUTATION; RADIATION; BELLOWS; LOSSES; RANGE AB A systematic review of theoretical results for the longitudinal and transverse impedances obtained by different methods is presented. Definitions, general theorems, modal analysis, diffraction model, and analytical results comprise the content of the paper. Several new results are included. In particular, necessary and sufficient conditions for the independence of the impedance on the beam longitudinal direction are given. The impedances of two basic simple structures - that of a cavity and that of a step - are studied in detail. The transition from the regime of a cavity to the regime of a step is explained, an approximate formula describing this transition is given, and the criterion for determining the applicability of each regime is established. The asymptotic behavior of the impedance for a finite number M of periodically arranged cavities as a function of M is studied. The difference in the behavior of the impedance for a single cavity and that for an infinite number of cavities is explained as the result of the interference of the diffracted waves. A criterion for determining the transition in the impedance behavior from small M to large M is presented. RP HEIFETS, SA (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 132 TC 43 Z9 44 U1 2 U2 6 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 JUL PY 1991 VL 63 IS 3 BP 631 EP 673 DI 10.1103/RevModPhys.63.631 PG 43 WC Physics, Multidisciplinary SC Physics GA FX970 UT WOS:A1991FX97000005 ER PT J AU SIKKA, VK AF SIKKA, VK TI DUCTILITY ENHANCEMENT OF IRON-ALUMINIDE ALLOYS SO SAMPE QUARTERLY-SOCIETY FOR THE ADVANCEMENT OF MATERIAL AND PROCESS ENGINEERING LA English DT Article AB Iron aluminides based on Fe3Al are ordered intermetallic alloys that offer good oxidation resistance, excellent sulfidation resistance, and low material cost. These materials also conserve strategic elements such as chromium and have a lower density than stainless steels. However, limited ductility at ambient temperature and a sharp drop in strength above 600-degrees-C have been major deterrents to their acceptance for structural applications. This paper presents results on iron aluminides with room-temperature elongations of 15 to 20%. Ductility values were improved by a combination of thermomechanical processing and heat-treatment control. This method of ductility improvement has been demonstrated for a range of compositions. The data presented in this paper suggest that the Fe3Al-based compositions tested are sensitive to environmental effects. The environment of concern is moisture in air that reacts with aluminum to form hydrogen at the metal surface. The hydrogen produced is adsorbed and absorbed in the specimens during plastic strain and results in low room-temperature ductilities. Results showed that the use of highly elongated grains produced by warm working increases ductility. A special heat treatment produces an additional improvement in ductility. RP SIKKA, VK (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37830, USA. NR 0 TC 17 Z9 17 U1 0 U2 1 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0036-0821 J9 SAMPE QUART PD JUL PY 1991 VL 22 IS 4 BP 2 EP 10 PG 9 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA FV453 UT WOS:A1991FV45300001 ER PT J AU KASSNER, ME WALL, MA SLEESWYK, AW AF KASSNER, ME WALL, MA SLEESWYK, AW TI SOME OBSERVATIONS DURING INSITU REVERSED DEFORMATION OF ALUMINUM SINGLE-CRYSTALS IN THE HVEM USING THE X-Y METHOD SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID INTERNAL-STRESSES; DISLOCATION; BEHAVIOR; STRAIN C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV MAT,LIVERMORE,CA 94550. UNIV GRONINGEN,ALGEMENE NATUURKUNDE LAB,9718 CM GRONINGEN,NETHERLANDS. RP KASSNER, ME (reprint author), OREGON STATE UNIV,DEPT MECH ENGN,CORVALLIS,OR 97331, USA. NR 21 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD JUL PY 1991 VL 25 IS 7 BP 1701 EP 1706 DI 10.1016/0956-716X(91)90478-J PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA FU814 UT WOS:A1991FU81400039 ER PT J AU CARLSON, RE FRITSCH, FN AF CARLSON, RE FRITSCH, FN TI A BIVARIATE INTERPOLATION ALGORITHM FOR DATA THAT ARE MONOTONE IN ONE VARIABLE SO SIAM JOURNAL ON SCIENTIFIC AND STATISTICAL COMPUTING LA English DT Article DE BIVARIATE INTERPOLATION; BICUBIC HERMITE SURFACES; SHAPE-PRESERVING INTERPOLATION AB This paper describes an algorithm for interpolating data on a rectangular mesh by piecewise bicubic functions. In [SIAM J. Numer. Anal., 26 (1989), pp. 1-9] the authors presented a monotonicity-preserving algorithm for data that are monotone in both variables. The present paper shows how the algorithm can be modified to treat data that are monotone in only one variable. RP CARLSON, RE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV COMP & MATH RES,LIVERMORE,CA 94550, USA. NR 3 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 0196-5204 J9 SIAM J SCI STAT COMP PD JUL PY 1991 VL 12 IS 4 BP 859 EP 866 DI 10.1137/0912046 PG 8 WC Mathematics, Applied SC Mathematics GA FT148 UT WOS:A1991FT14800009 ER PT J AU DRITTLER, B WEINERT, M ZELLER, R DEDERICHS, PH AF DRITTLER, B WEINERT, M ZELLER, R DEDERICHS, PH TI VACANCY FORMATION ENERGIES OF FCC TRANSITION-METALS CALCULATED BY A FULL POTENTIAL GREEN-FUNCTION METHOD SO SOLID STATE COMMUNICATIONS LA English DT Article ID MUFFIN-TIN POTENTIALS; MULTIPLE-SCATTERING; BAND-THEORY; ALUMINUM; MONOVACANCY; ELECTRON AB We present calculations for the vacancy formation energies of some 3d and 4d fcc and hcp transition metals using local density functional theory. We have developed a full potential extension of the KKR-Green's function method and show how reliable total energies can be calculated. For Cu and Ag our calculated vacancy formation energies are within 0.1 eV in agreement with experiments. For the other metals the agreement is reasonable in view of the greater experimental uncertainties. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP DRITTLER, B (reprint author), FORSCHUNGSZENTRUM JULICH,INST FESTKORPERFORSCH,W-5170 JULICH,GERMANY. RI Zeller, Rudolf/K-7094-2013 OI Zeller, Rudolf/0000-0002-9462-2649 NR 30 TC 61 Z9 61 U1 1 U2 13 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 JUL PY 1991 VL 79 IS 1 BP 31 EP 35 DI 10.1016/0038-1098(91)90474-A PG 5 WC Physics, Condensed Matter SC Physics GA GA288 UT WOS:A1991GA28800008 ER PT J AU ANDRAKA, B JEE, CS KIM, JS STEWART, GR CARLSON, KD WANG, HH CROUCH, AVS KINI, AM WILLIAMS, JM AF ANDRAKA, B JEE, CS KIM, JS STEWART, GR CARLSON, KD WANG, HH CROUCH, AVS KINI, AM WILLIAMS, JM TI SPECIFIC-HEAT OF THE HIGH-TC ORGANIC SUPERCONDUCTOR KAPPA-(ET)2CU[N(CN)2]BR SO SOLID STATE COMMUNICATIONS LA English DT Article ID MAGNETIC-FIELDS; BEDT-TTF; BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE; BETA-(ET)2AUI2 AB An anomaly in the specific heat of kappa-(ET)2 Cu[N(CN)2]Br, where ET is the radical-cation donor molecule bis(ethylenedithio)tetrathiafulvalene, has been observed around T(c) approximately 11.5 K, indicating bulk superconductivity in this organic charge-transfer salt. The normal-state electronic specific heat coefficient, gamma = 22 +/- 3 mJ K-2 mol was obtained by the suppression of superconductivity with a sufficiently strong magnetic field applied parallel to the crystallographic b direction. The ratio of the specific heat discontinuity DELTA-C to gamma-T indicates strong coupling. Comparisons with other ET-based organic superconductors are made. C1 ARGONNE NATL LAB,DIV CHEM & MAT SCI,ARGONNE,IL 60439. UNIV AUGSBURG,W-8900 AUGSBURG,GERMANY. RP ANDRAKA, B (reprint author), UNIV FLORIDA,DEPT PHYS,GAINESVILLE,FL 32611, USA. RI Kini, Aravinda/F-4467-2012 NR 11 TC 49 Z9 49 U1 0 U2 2 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 JUL PY 1991 VL 79 IS 1 BP 57 EP 59 DI 10.1016/0038-1098(91)90479-F PG 3 WC Physics, Condensed Matter SC Physics GA GA288 UT WOS:A1991GA28800013 ER PT J AU WARREN, WL LENAHAN, PM BRINKER, CJ AF WARREN, WL LENAHAN, PM BRINKER, CJ TI RELATIONSHIP BETWEEN STRAINED SILICON-OXYGEN BONDS AND RADIATION-INDUCED PARAMAGNETIC POINT-DEFECTS IN SILICON DIOXIDE SO SOLID STATE COMMUNICATIONS LA English DT Article ID SI-29 HYPERFINE-STRUCTURE; ELECTRON-SPIN-RESONANCE; AMORPHOUS SIO2; HIGH-PURITY; HOLE CENTER; A-SIO2; GLASS; MODEL; RINGS; RAMAN AB We have investigated the radiation induced generation of paramagnetic point defects in high surface area sol-gel silicates containing various concentrations of the Raman active 608 cm-1 D2 band attributed to strained cyclic trisiloxanes (3-membered rings). Our results suggest a correlation between the concentration of the 3-membered rings with the concentration of radiation induced paramagnetic E' (trivalent silicon center) and oxygen centers, thus, providing the first substantive evidence of the relationship between a specific strained siloxane structure and radiation damage in amorphous silicon dioxide. C1 PENN STATE UNIV,UNIVERSITY PK,PA 16802. SANDIA NATL LABS,DIV INORGAN MAT CHEM,ALBUQUERQUE,NM 87185. RP WARREN, WL (reprint author), SANDIA NATL LABS,DIV ELECTR PROPERTIES MAT,ALBUQUERQUE,NM 87185, USA. NR 27 TC 9 Z9 9 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD JUL PY 1991 VL 79 IS 2 BP 137 EP 141 DI 10.1016/0038-1098(91)90077-9 PG 5 WC Physics, Condensed Matter SC Physics GA FX473 UT WOS:A1991FX47300008 ER PT J AU VILA, R IBARRA, A DECASTRO, MJ CLINARD, FW AF VILA, R IBARRA, A DECASTRO, MJ CLINARD, FW TI THERMALLY STIMULATED DEPOLARIZATION CURRENTS IN NEUTRON-IRRADIATED AL2O3 SO SOLID STATE COMMUNICATIONS LA English DT Article ID SINGLE-CRYSTAL AL2O3; CENTERS AB Two thermally stimulated depolarization current peaks due to dipolar relaxation processes have been observed at 242 and 273 K in neutron irradiated Al2O3. The results on fluence dependence and thermal stability indicate that the second one may be related to F-type centres or their corresponding interstitials induced by irradiation. C1 CSIC,INST CIENCIA MAT,E-28006 MADRID,SPAIN. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP VILA, R (reprint author), EURATOM,CIEMAT FUS,AVDA COMPLUTENSE 22,E-28040 MADRID,SPAIN. RI VILA, RAFAEL/C-5903-2011; Jimenez de Castro, Miguel/H-6062-2015; OI VILA, RAFAEL/0000-0001-5760-7039; Jimenez de Castro, Miguel/0000-0002-2816-0394; Ibarra, Angel/0000-0002-2420-2497 NR 19 TC 3 Z9 3 U1 0 U2 2 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 JUL PY 1991 VL 79 IS 4 BP 295 EP 297 DI 10.1016/0038-1098(91)90549-B PG 3 WC Physics, Condensed Matter SC Physics GA GC135 UT WOS:A1991GC13500004 ER PT J AU MCCARTY, KF LIU, JZ JIA, YX SHELTON, RN RADOUSKY, HB AF MCCARTY, KF LIU, JZ JIA, YX SHELTON, RN RADOUSKY, HB TI EFFECT OF GOLD-DOPING ON THE ENERGY-GAP OF YBA2CU3O7 AS DETERMINED BY RAMAN-SCATTERING SO SOLID STATE COMMUNICATIONS LA English DT Article ID SINGLE-CRYSTAL YBA2CU3O7-DELTA; SUPERCONDUCTING GAP; ANISOTROPY; POLARIZATION AB A comparison has been made of the Raman scattering from YBa2Cu3O7 crystals that were grown in gold and zirconia crucibles and that contain 0.74 atomic-% gold and approximately 0.009 atomic-% zirconium, respectively. Differences exist in the absolute values of the phonon line widths in the two types of crystals. However, gold substitution is found to have little effect on the temperature dependence of the line widths of the A(g) phonons since nearly the same trends are observed in both types of crystals. In particular, the 340-cm-1 phonon becomes significantly more symmetric and sharper below T(c), in distinct disagreement with the results of other researchers. The line widths of the A(g) phonons support a superconducting energy gap bounded between 440 and 500 cm-1 (2-DELTA = 6.8 - 7.7 k(B)T(c)). C1 UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP MCCARTY, KF (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94551, USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 25 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD JUL PY 1991 VL 79 IS 4 BP 359 EP 362 DI 10.1016/0038-1098(91)90561-9 PG 4 WC Physics, Condensed Matter SC Physics GA GC135 UT WOS:A1991GC13500016 ER PT J AU CHANG, FH BARNES, TS SCHILD, D GNIRKE, A BLESKAN, J PATTERSON, D AF CHANG, FH BARNES, TS SCHILD, D GNIRKE, A BLESKAN, J PATTERSON, D TI EXPRESSION OF A HUMAN CDNA-ENCODING A PROTEIN CONTAINING GAR SYNTHETASE, AIR SYNTHETASE, AND GAR TRANSFORMYLASE CORRECTS THE DEFECTS IN MUTANT CHINESE-HAMSTER OVARY CELLS LACKING THESE ACTIVITIES SO SOMATIC CELL AND MOLECULAR GENETICS LA English DT Article ID GLYCINAMIDE RIBONUCLEOTIDE SYNTHETASE; MULTIFUNCTIONAL PROTEIN; GEL-ELECTROPHORESIS; HUMAN CHROMOSOME-21; HUMAN-FIBROBLASTS; CHICKEN LIVER; DROSOPHILA; GENES; FRAGMENTS; YEAST AB The isolation of a human cDNA encoding the multifunctional protein containing GAR synthetase, AIR synthetase, and GAR transformylase by functional complementation of purine auxotrophy in yeast has been reported. Chinese hamster ovary (CHO) cell mutant purine auxotrophs deficient in GAR synthetase (Ade-C) or AIR synthetase plus GAR transformylase (Ade-G) activities were transfected with this human GART cDNA subcloned into a mammalian expression vector. This restored 49-140% of the activities of GAR synthetase, AIR synthetase, and GAR transformylase in transfected cells when compared to wild-type CHO K1 parental cells. Study of one stably expressing transfectant, AdeC2, revealed that the human GART cDNA was incorporated into the CHO genome. The enzyme activities appear to be associated with an expressed protein of 110 kDa, very similar to that of purified human GART trifunctional enzyme. The Ade-C mutant shows reduced amounts of GART mRNA compared to CHO K1 and a protein of apparently reduced size, results consistent with the purine requirement and enzyme deficiency observed in the mutant. These experiments provide definitive evidence that the human GART cDNA encodes and can direct the production of active human GART trifunctional protein in mammalian cells. They also provide important evidence that the Ade-C and Ade-G mutants of CHO cells are defective in this gene. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. WASHINGTON UNIV,SCH MED,DEPT GENET,ST LOUIS,MO 63110. RP CHANG, FH (reprint author), ELEANOR ROOSEVELT INST CANC RES,1899 GAYLORD ST,DENVER,CO 80206, USA. FU NIA NIH HHS [AG-00029]; NICHD NIH HHS [HD22720] NR 38 TC 7 Z9 7 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0740-7750 J9 SOMAT CELL MOLEC GEN JI Somat.Cell Mol.Genet. PD JUL PY 1991 VL 17 IS 4 BP 411 EP 420 DI 10.1007/BF01233066 PG 10 WC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity GA GE701 UT WOS:A1991GE70100009 PM 1887337 ER PT J AU DONGARRA, JJ MAYES, P DIBROZOLO, GR AF DONGARRA, JJ MAYES, P DIBROZOLO, GR TI THE IBM RISC SYSTEM-6000 AND LINEAR ALGEBRA OPERATIONS SO SUPERCOMPUTER LA English DT Article ID SUBPROGRAMS; SET AB This paper discusses the IBM RISC System/6000 workstation and a set of experiments with blocked algorithms commonly used in solving problems in numerical linear algebra. We describe the performance of these algorithms and discuss the techniques used in achieving high performance on such an architecture. C1 OAK RIDGE NATL LAB,MATH SCI SECT,OAK RIDGE,TN 37831. NAG LTD,OXFORD OX2 8DR,ENGLAND. IBM CORP,EUROPEAN CTR SCI & ENGN COMP,I-00147 ROME,ITALY. RP DONGARRA, JJ (reprint author), UNIV TENNESSEE,DEPT COMP SCI,KNOXVILLE,TN 37996, USA. RI Dongarra, Jack/E-3987-2014 NR 10 TC 6 Z9 6 U1 0 U2 0 PU ASFRA PI EDAM PA VOORHAVEN 33, 1135 BL EDAM, NETHERLANDS SN 0168-7875 J9 SUPERCOMPUTER JI Supercomputer PD JUL PY 1991 VL 8 IS 4 BP 15 EP 30 PG 16 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA GJ152 UT WOS:A1991GJ15200003 ER PT J AU ECHENIQUE, PM FLORES, F RITCHIE, RH AF ECHENIQUE, PM FLORES, F RITCHIE, RH TI IMAGE POTENTIAL EFFECTS FOR LOW AND HIGH-ENERGY ELECTRONS SO SURFACE SCIENCE LA English DT Article ID WEIGHTED-DENSITY APPROXIMATION; METAL-SURFACE INTERACTION; REFERENCE-PLANE POSITION; TUNNELING ELECTRONS; SELF-ENERGY; VANDERWAALS INTERACTION; FUNCTIONAL CALCULATION; INVERSE PHOTOEMISSION; DIELECTRIC SPHERES; FIELD-EMISSION AB Developments in the theory of the image potential of charged particles moving near condensed matter surfaces are sketched. Some applications to electrons, (i) localized in image potential states, (ii) tunneling across a gap between two metals, (iii) localized in fast microprobe beams, are considered. C1 UNIV AUTONOMA MADRID, DEPT FIS MAT CONDENSADA C12, E-28049 MADRID, SPAIN. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. UNIV TENNESSEE, DEPT PHYS, KNOXVILLE, TN 37996 USA. RP ECHENIQUE, PM (reprint author), UNIV BASQUE COUNTRY, FAC QUIM, DEPT FIS MAT, APDO 1072, E-20008 SAN SEBASTIAN, SPAIN. RI Flores, fernando/K-2362-2014 NR 97 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 251 BP 119 EP 126 DI 10.1016/0039-6028(91)90965-U PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FY126 UT WOS:A1991FY12600024 ER PT J AU BARDI, U ATREI, A ROVIDA, G ROSS, PN AF BARDI, U ATREI, A ROVIDA, G ROSS, PN TI STRUCTURE OF THE COBALT OXIDE LAYER FORMED BY LOW-PRESSURE OXIDATION OF THE PT80CO20(100) SURFACE - A STUDY BY LEED, LEIS AND XPS SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 11TH EUROPEAN CONF ON SURFACE SCIENCE ( ECOSS-11 ) CY OCT 01-04, 1990 CL UNIV SALAMANCA, SALAMANCA, SPAIN SP EUROPEAN PHYS SOC, DIV CONDENSED MATTER, INTERFACE SECT, INT UNION VACUUM SCI TECH & APPL, DIV SURFACE SCI HO UNIV SALAMANCA ID 001 SURFACE; ALLOY AB The oxidation of the Pt80Co20(001) surface was studied at oxygen pressures lower than 1 x 10(-5) Torr and temperatures higher than 600 K by a combination of surface-sensitive techniques. The results obtained by XPS and LEIS indicate that the film of oxide grows forming islands of uniform thickness of the order of a single CoO layer. The LEED results indicate that the structure of the islands is related to that of bulk cobalt monoxide. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM RES,BERKELEY,CA 94720. RP BARDI, U (reprint author), UNIV FLORENCE,DIPARTMENTO CHIM,I-50121 FLORENCE,ITALY. RI Bardi, Ugo/L-1978-2015 OI Bardi, Ugo/0000-0003-2240-2070 NR 11 TC 13 Z9 13 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 251 BP 727 EP 730 DI 10.1016/0039-6028(91)91087-E PG 4 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FY126 UT WOS:A1991FY12600146 ER PT J AU BRAATEN, NA GREPSTAD, JK RAAEN, S QIU, SL AF BRAATEN, NA GREPSTAD, JK RAAEN, S QIU, SL TI K PROMOTED OXIDATION OF AL AND TA SO SURFACE SCIENCE LA English DT Article ID THIN CERIUM OVERLAYERS; ALKALI-METALS; ELECTRONIC-STRUCTURE; ENHANCED OXIDATION; ADSORPTION; SPECTROSCOPY; SURFACES; POTASSIUM; ALUMINUM; SHIFTS AB Core level and valence band photoemission have been used to study the response to oxygen exposure of potassium-precovered, polycrystalline aluminum and tantalum substrates. Deposition of potassium overlayers in the coverage regime from zero to one monolayer, results in an increase of the rate of oxygen uptake for both substrates. The increased oxygen uptake is, however, relatively stronger on aluminum. Correlated measurements of work function and oxygen uptake show that there is a correspondence between these two parameters for low K coverages, i.e., lower work function results in higher oxygen uptake. These results may be understood in terms of a model in which the alkali atoms are increasing the rate of dissociation of oxygen molecules at the surface, as well as lowering the barrier for oxygen penetration into the surface, through a reduction in the system work function. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. RP BRAATEN, NA (reprint author), UNIV TRONDHEIM,NTH,N-7034 TRONDHEIM,NORWAY. NR 29 TC 16 Z9 16 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 JUL PY 1991 VL 250 IS 1-3 BP 51 EP 58 DI 10.1016/0039-6028(91)90708-Z PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600013 ER PT J AU MAURICE, V TAKEUCHI, K SALMERON, M SOMORJAI, GA AF MAURICE, V TAKEUCHI, K SALMERON, M SOMORJAI, GA TI THE BONDING OF DIETHYL-ETHER, ETHANOL AND THEIR FLUORINATED ANALOGS TO ZIRCONIUM-OXIDE THIN-FILMS SO SURFACE SCIENCE LA English DT Article ID TEMPERATURE-PROGRAMMED DESORPTION; OXIDATIVE-DEGRADATION REACTIONS; DECOMPOSITION PATHWAYS; PERFLUOROALKYL ETHERS; SURFACE-CHEMISTRY; PLATINUM 111; RU(001); ADSORPTION; ALCOHOLS; WATER AB We report a thermal desorption study of the interaction of water, diethyl ether, ethanol, perfluorodiethyl ether, and 2,2,2-trifluoroethanol with zirconium oxide thin films epitaxially grown on Pt(111) single-crystal surfaces, and with the Pt(111) metal surface for comparison. We find that water and the hydrogenated ether interact chemically with the oxide surface through the O lone pair, whereas the fluorinated ether has only a van der Waals interaction. Ethanol and 2,2,2-trifluoroethanol are decomposed to some extent on zirconium oxide upon heating. Fluorination decreases the bond strength between the molecules and the oxide surface. A similar trend is observed on the Pt(111) surface with regard to relative adsorptivity and reactivity of the adsorbates examined. Although the Pt(111) surface provides weaker interaction with the molecules that interact via O lone pair orbitals (water, ether and alcohol) than the oxide surface, it decomposes diethyl ether as well as the alcohols. C1 UNIV PARIS 06,ECOLE NATL SUPER CHIM PARIS,PHYSICOCHIM SURFACES LAB,UA 425,F-75231 PARIS 05,FRANCE. AGCY IND SCI & TECHNOL,NATL RES INST POLLUT & RESOURCES,DEPT ATMOSPHER ENVIRONM PROTECT,TSUKUBA,IBARAKI 305,JAPAN. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. RP MAURICE, V (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR ADV MAT,BERKELEY,CA 94720, USA. RI Maurice, Vincent/F-9196-2015 OI Maurice, Vincent/0000-0001-5222-9972 NR 35 TC 32 Z9 32 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 250 IS 1-3 BP 99 EP 111 DI 10.1016/0039-6028(91)90713-3 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600018 ER PT J AU PAFFETT, MT LOGAN, AD SIMONSON, RJ KOEL, BE AF PAFFETT, MT LOGAN, AD SIMONSON, RJ KOEL, BE TI A MULTITECHNIQUE SURFACE SCIENCE EXAMINATION OF SN DEPOSITION ON PT(100) SO SURFACE SCIENCE LA English DT Article ID ALKALI-ION-SCATTERING; CO; CHEMISORPTION; ALLOYS; ADSORPTION; PLATINUM; EXPOSURE; PT(111); TIN; SPECTROSCOPY AB Interfaces prepared by vapor deposition of Sn onto Pt(100) surfaces have been examined using the following techniques: Auger electron and X-ray photoelectron spectroscopy (AES and XPS), low-energy electron diffraction (LEED), and low-energy ion surface scattering (LEISS) with Ne+ ions. Tin deposition was conducted at 320 and 600 K, and the surface composition and order was examined as a function of further annealing to 1200 K. The AES uptake plots (signal versus deposition time) indicate that the Sn growth mode can be described by a layer-by-layer process only up to one adlayer at 320 K. Some evidence of 3D growth is inferred from LEED and LEISS data for higher Sn coverages. For deposition at 600 K, AES data indicate significant interdiffusion and surface alloy formation. LEED observations (recorded at a substrate temperature of 320 K) show that the characteristic hexagonal Pt(100) reconstruction disappears with Sn exposures of 4.6 x 10(14) atoms cm2 (theta-Sn = 0.35 monolayer (ML)). Further Sn deposition results in a c(2 x 2) LEED pattern starting at a coverage of slightly above 0.5 ML. The c(2 X 2) LEED pattern becomes progressively more diffuse with increasing Sn exposure with eventual loss of all LEED features above 2.2 ML. Annealing experiments with various precoverages of Sn on Pt(100) are also described by AES, LEED, and LEISS results. For specific Sn precoverages and annealing conditions, c(2 x 2), p(3 square-root 2 x square-root 2)R45-degrees, and a combination of the two LEED patterns are observed. These ordered LEED patterns are suggested to arise from ordered PtSn surface alloys. In addition, the chemisorption of CO and O2 at the ordered annealed Sn/Pt(100) surfaces was also examined using thermal desorption mass spectroscopy (TDMS), AES, and LEED. C1 UNIV SO CALIF,DEPT CHEM,LOS ANGELES,CA 90089. RP PAFFETT, MT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV CLS,LOS ALAMOS,NM 87545, USA. RI Koel, Bruce/H-3857-2013 OI Koel, Bruce/0000-0002-0032-4991 NR 38 TC 37 Z9 37 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 250 IS 1-3 BP 123 EP 138 DI 10.1016/0039-6028(91)90715-5 PG 16 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600020 ER PT J AU SCHROTT, AG FRANKEL, GS DAVENPORT, AJ ISAACS, HS JAHNES, CV RUSSAK, MA AF SCHROTT, AG FRANKEL, GS DAVENPORT, AJ ISAACS, HS JAHNES, CV RUSSAK, MA TI CRLVV AUGER EMISSION AND PHOTOREDUCTION OF HEXAVALENT CR OXIDES SO SURFACE SCIENCE LA English DT Article ID X-RAY PHOTOEMISSION; ELECTRONIC-STRUCTURE; PHOTOELECTRON-SPECTROSCOPY; CHROMIUM COMPOUNDS; SURFACE; DESORPTION; DIHALIDES; SPECTRA; ALLOYS; CORE AB The CrLVV Auger emission has been used to investigate the local chemical environment of Cr(VI) in connection with the photoreduction produced by a non-monochromatic X-ray source. We compared Cr(VI) in oxides on anodized Al exposed to a chromate solution, with Cr(VI) in oxides on Al/Cr alloys polarized in a borate solution. The former were found to be much more sensitive to photoreduction than the latter. This is correlated with the intensity of the CrLVV Auger emission, attributed to a charge transfer transition in the final state of the photoemission process. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP SCHROTT, AG (reprint author), IBM CORP,DIV RES,TJ WATSON RES CTR,POB 218,YORKTOWN HTS,NY 10598, USA. RI Davenport, Alison/J-6089-2013 OI Davenport, Alison/0000-0003-0853-515X NR 25 TC 21 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 250 IS 1-3 BP 139 EP 146 DI 10.1016/0039-6028(91)90716-6 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600021 ER PT J AU CHEN, Y TONG, SY ROCCA, M MORETTO, P VALBUSA, U BOHNEN, KP HO, KM AF CHEN, Y TONG, SY ROCCA, M MORETTO, P VALBUSA, U BOHNEN, KP HO, KM TI HIGH-RESOLUTION ELECTRON ENERGY-LOSS SPECTROSCOPY ANALYSIS OF AG(001) - DISCOVERY OF A NEW SURFACE LONGITUDINAL MODE USING 1ST-PRINCIPLES PHONON CALCULATIONS SO SURFACE SCIENCE LA English DT Letter ID CROSS-SECTION ANALYSIS; ADSORBATE VIBRATIONS; BULK PHONONS; SCATTERING; DISPERSION; CU(100); DIRECTION; DYNAMICS; AG(100); EELS AB We present analysis of electron-energy loss spectra of Ag(001) using first-principles surface phonon and multiple scattering inelastic cross-section calculations. Excellent agreement with experiment is obtained. The study reveals a new longitudinal surface phonon at MBAR which causes the measured loss peak to shift as the incident energy is varied. These results demonstrate the importance of using accurate theory for proper interpretation of EELS spectra and indicate that force-constant models with adjustable parameters may be misleading. C1 UNIV WISCONSIN,DEPT PHYS,MILWAUKEE,WI 53201. UNIV GENOA,DIPARTMENTO FIS,I-16126 GENOA,ITALY. CNR,CTR FIS SUPERFICI & BASSE TEMP,GENOA,ITALY. KERNFORSCHUNGSZENTRUM KARLSRUHE GMBH,INFP,W-7500 KARLSRUHE 1,GERMANY. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP CHEN, Y (reprint author), UNIV WISCONSIN,SURFACE STUDIES LAB,MILWAUKEE,WI 53201, USA. NR 20 TC 16 Z9 16 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUL PY 1991 VL 250 IS 1-3 BP L389 EP L394 DI 10.1016/0167-2584(91)90556-7 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600007 ER PT J AU DAWSON, P HAAS, JW ALEXANDER, KB THOMPSON, J FERRELL, TL AF DAWSON, P HAAS, JW ALEXANDER, KB THOMPSON, J FERRELL, TL TI SURFACE ENHANCED RAMAN-SCATTERING FROM MILDLY ROUGHENED SURFACES - VARIATION OF SIGNAL WITH METAL GRAIN-SIZE SO SURFACE SCIENCE LA English DT Letter ID SCANNING TUNNELING MICROSCOPY; SILVER; ROUGHNESS; DEPENDENCE; MECHANISM AB The intensity of surface enhanced Raman scattering from benzoic acid derivatives on mildly roughened, thermally evaporated Ag films shows a remarkably strong dependence on metal grain size. Large grained (slowly deposited) films give a superior response, by up to a factor of 10, to small grained (quickly deposited) films, with films of intermediate grain size yielding intermediate results. The optical field amplification underlying the enhancement mechanism is due to the excitation of surface plasmon polaritons (SPPs). Since surface roughness characteristics, as determined by STM, remain relatively constant as a function of deposition rate, it is argued that the contrast in Raman scattering is due to differences in elastic grain boundary scattering of SPPs (leading to different degrees of internal SPP damping), rather than differences in the interaction of SPPs with surface inhomogeneities. C1 OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37830. RP DAWSON, P (reprint author), QUEENS UNIV BELFAST,DEPT PURE & APPL PHYS,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. NR 17 TC 13 Z9 13 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 JUL PY 1991 VL 250 IS 1-3 BP L383 EP L388 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA GA376 UT WOS:A1991GA37600006 ER PT J AU SZOKE, A MOIR, RW AF SZOKE, A MOIR, RW TI A PRACTICAL ROUTE TO FUSION POWER SO TECHNOLOGY REVIEW LA English DT Article RP SZOKE, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MASS INST TECHNOL PI CAMBRIDGE PA CAMBRIDGE, MA 02139 SN 0040-1692 J9 TECHNOL REV JI Technol. Rev. PD JUL PY 1991 VL 94 IS 5 BP 21 EP 27 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FQ947 UT WOS:A1991FQ94700006 ER PT J AU HARRISON, RJ KENDALL, RA AF HARRISON, RJ KENDALL, RA TI A PARALLEL VERSION OF ARGOS - A DISTRIBUTED MEMORY MODEL FOR SHARED MEMORY UNIX COMPUTERS SO THEORETICA CHIMICA ACTA LA English DT Article DE PARALLEL ALGORITHMS; SHARED MEMORY COMPUTERS; ABINITIO ALGORITHMS ID COMPUTATIONAL CHEMISTRY; QUANTUM-CHEMISTRY; PROCESSOR; ENERGY AB A distributed memory programming model was used in a fully parallel implementation of the ab initio integral evaluation program ARGOS (R. Pitzer (1973) J. Chem. Phys. 58:3111), on shared memory UNIX computers. The method used is applicable to many similar problems, including derivative integral evaluation. Only a few lines of the existing sequential FORTRAN source required modification. Initial timings on several multi-processor computers are presented. A simplified version of the programming tool used is also presented, and general consideration is given to the parallel implementation of quantum chemistry algorithms. RP HARRISON, RJ (reprint author), ARGONNE NATL LAB,THEORET CHEM GRP,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 22 TC 26 Z9 26 U1 1 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 JUL PY 1991 VL 79 IS 5 BP 337 EP 347 DI 10.1007/BF01114692 PG 11 WC Chemistry, Physical SC Chemistry GA FV423 UT WOS:A1991FV42300001 ER PT J AU TRAVIS, CC BOWERS, JC AF TRAVIS, CC BOWERS, JC TI INTERSPECIES SCALING OF ANESTHETIC POTENCY SO TOXICOLOGY AND INDUSTRIAL HEALTH LA English DT Article ID MINIMUM ALVEOLAR CONCENTRATION; NITROUS-OXIDE; GENERAL ANESTHETICS; ISOFLURANE POTENCY; CONCENTRATION MAC; HALOTHANE; ENFLURANE; I-653; RATS; CAT AB Anesthetic potency data for 11 volatile anesthetics were correlated against body weight in multiple mammalian species, including man. The results indicate that the alveolar concentration necessary to produce anesthesia is approximately constant across species. Because alveolar ventilation rates scale with the 0.75 power of body weight, this implies that administered dose measured in mg/kg0.75/day produces the same anesthetic effect in all species. This analysis provides further support for the use of a mg/kg0.75/day interspecies scaling metric for acute toxic effects. RP TRAVIS, CC (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,RISK ANAL SECT,OAK RIDGE,TN 37831, USA. NR 67 TC 18 Z9 18 U1 0 U2 1 PU PRINCETON SCIENTIFIC PUBL INC PI PRINCETON PA PO BOX 2155, PRINCETON, NJ 08543 SN 0748-2337 J9 TOXICOL IND HEALTH JI Toxicol. Ind. Health PD JUL PY 1991 VL 7 IS 4 BP 249 EP 260 PG 12 WC Public, Environmental & Occupational Health; Toxicology SC Public, Environmental & Occupational Health; Toxicology GA GM823 UT WOS:A1991GM82300002 PM 1776156 ER PT J AU REX, M AF REX, M TI FROM THE VOICE MAIL PHONE LINE SO TRAINING & DEVELOPMENT LA English DT Letter RP REX, M (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC TRAINING DEVELOP INC PI ALEXANDRIA PA 1640 KING ST, BOX 1443, ALEXANDRIA, VA 22313-2043 SN 1055-9760 J9 TRAINING DEV JI Train. Dev. PD JUL PY 1991 VL 45 IS 7 BP 4 EP 4 PG 1 WC Business SC Business & Economics GA FZ149 UT WOS:A1991FZ14900001 ER PT J AU RATHI, AK AF RATHI, AK TI TRAFFIC METERING - AN EFFECTIVENESS STUDY SO TRANSPORTATION QUARTERLY LA English DT Article RP RATHI, AK (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831, USA. NR 12 TC 5 Z9 6 U1 0 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 JUL PY 1991 VL 45 IS 3 BP 421 EP 440 PG 20 WC Transportation SC Transportation GA FU909 UT WOS:A1991FU90900009 ER PT J AU LUXMOORE, RJ AF LUXMOORE, RJ TI A SOURCE SINK FRAMEWORK FOR COUPLING WATER, CARBON, AND NUTRIENT DYNAMICS OF VEGETATION SO TREE PHYSIOLOGY LA English DT Article AB Feedbacks between photosynthesis and growth and the influence on these relationships of environmental factors are reviewed. The evidence indicates a strong dependence of photosynthesis on photosynthate utilization. It also indicates that growth is more sensitive than photosynthesis to water and mineral nutrient stress. As a consequence, many relationships between photosynthesis and external driving variables are confounded by internal feedback effects that reflect the influence of external factors on growth. A source-sink framework for modeling carbon dynamics with coupled water and nutrient interactions in soil-plant systems is outlined. Simulations based on these concepts suggest that sink feedback regulation of photosynthesis at various times in diurnal, wetting-drying, and annual cycles is probably a common occurrence in soil-plant systems. RP LUXMOORE, RJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 0 TC 51 Z9 57 U1 0 U2 6 PU HERON PUBLISHING PI VICTORIA PA BOX 5579 STATION B, VICTORIA BC V8R 6S4, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD JUL-SEP PY 1991 VL 9 IS 1-2 BP 267 EP 280 PG 14 WC Forestry SC Forestry GA GF224 UT WOS:A1991GF22400018 ER PT J AU LUXMOORE, RJ KING, AW THARP, ML AF LUXMOORE, RJ KING, AW THARP, ML TI APPROACHES TO SCALING UP PHYSIOLOGICALLY BASED SOIL PLANT-MODELS IN SPACE AND TIME SO TREE PHYSIOLOGY LA English DT Article AB Many broad-scale, environmental phenomena can be investigated by extrapolating from detailed study of events at a small scale. This paper evaluates approaches to the use of physiologically based soil-plant models for addressing broad-scale, environmental issues. When the space and time domains of a soil-plant simulator are extended, there is an increase in the variability of soil, plant, and weather variables, which can be dealt with by what is called extended-range modeling, ERM. There may also be a gain of phenomena not represented at the small scale, which can be dealt with by what is called phenomena-added modeling, PAM. As an example of ERM, a Monte Carlo procedure, called Latin hypercube sampling, is used to estimate annual photosynthate production of an oak-hickory forest under three atmospheric CO2 concentrations. Phenomena-added modeling is illustrated by scaling up spatially from a vegetated plot to a watershed, and scaling up temporally from a physiological model with hourly time steps to a forest-succession model operating on annual time steps. Where large-scale processes take place on a time scale similar to, or faster than, that of small-scale processes (plot-watershed case), less computation is required if the small-scale processes are built into the large-scale model and ERM is conducted with the expanded model. Phenomena-added modeling may be conducted by information transfer from a small-scale simulator to a large-scale simulator. This is also possible with Latin hypercube sampling by using the output frequency distributions from the small-scale model as input distributions for the large-scale model. The final outputs at the large scale are also frequency distributions, and these can be used to determine confidence intervals for statistical comparisons among modeling scenarios. The ERM and PAM methods are data and computer intensive; nevertheless, they can fill an important need for addressing large-scale issues that cannot be adequately addressed through other scaling up methods. RP LUXMOORE, RJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 0 TC 20 Z9 22 U1 0 U2 0 PU HERON PUBLISHING PI VICTORIA PA BOX 5579 STATION B, VICTORIA BC V8R 6S4, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD JUL-SEP PY 1991 VL 9 IS 1-2 BP 281 EP 292 PG 12 WC Forestry SC Forestry GA GF224 UT WOS:A1991GF22400019 ER PT J AU HUSTON, MA AF HUSTON, MA TI USE OF INDIVIDUAL-BASED FOREST SUCCESSION MODELS TO LINK PHYSIOLOGICAL WHOLE-TREE MODELS TO LANDSCAPE-SCALE ECOSYSTEM MODELS SO TREE PHYSIOLOGY LA English DT Article AB Models of the spatial and temporal dynamics of forests that are based on competition between individual plants can be used to predict changes in the abundance of different tree species that result from natural succession or environmental change. These individual-based models can be designed to take into account important physiological and chemical properties of individual species, and thus provide a mechanism for scaling up the predictions of whole-plant physiological process models to intermediate-scale patterns in ecosystems and landscapes. Because plant species differ greatly in such properties as carbon fixation and evapotranspiration rates, models that predict species composition could provide information on the distribution of parameter values used as input for large-scale (e.g., "big leaf") models of regional vegetation-atmosphere interactions. RP HUSTON, MA (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. RI Huston, Michael/B-1434-2009 OI Huston, Michael/0000-0001-9513-1166 NR 0 TC 11 Z9 11 U1 0 U2 0 PU HERON PUBLISHING PI VICTORIA PA BOX 5579 STATION B, VICTORIA BC V8R 6S4, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD JUL-SEP PY 1991 VL 9 IS 1-2 BP 293 EP 306 PG 14 WC Forestry SC Forestry GA GF224 UT WOS:A1991GF22400020 ER PT J AU BLAU, PJ AF BLAU, PJ TI SCALE EFFECTS IN STEADY-STATE FRICTION SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT TRIBOLOGY CONF CY OCT 08-10, 1990 CL TORONTO, CANADA SP AMER SOC MECH ENGINEERS, SOC TRIBOLOGISTS & LUBRICAT ENGINEERS AB Sliding friction phenomena have long been the subject of study and modeling. The physical portrayal of the sliding contact upon which such models are based is often a function of the modeler's background, and may range from the atomic scale to the scale of more macroscopic surface roughness. Sometimes, quasi-static arguments are inappropriately applied to sliding situations. The current paper examines the nature of frictional variations during sliding contact. High recording-rate instrumentation was used to analyze detailed, point-to-point variations in friction force for selfmated, pin-on-disk experiments with alumina and aluminum specimens. Data indicate that friction mechanism, even on a fine scale, must be modeled considering the whole tribosystem, not just the interfacial materials properties alone. The contact conditions stimulate the displacements in the tribocomponents, which in turn result in sensible mechanical output. It is physically unrealistic to develop sliding solid friction models which predict only a single friction valve, rather a range of values typical of the variation experienced by the dynamic tribosystem should be developed. A systems approach rather than a discrete asperity approach may ultimately prove to be most productive for modeling tribosystems of engineering interest. RP BLAU, PJ (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 17 TC 14 Z9 14 U1 1 U2 1 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 JUL PY 1991 VL 34 IS 3 BP 335 EP 342 DI 10.1080/10402009108982042 PG 8 WC Engineering, Mechanical SC Engineering GA FU915 UT WOS:A1991FU91500003 ER PT J AU RUBIN, Y AF RUBIN, Y TI TRANSPORT IN HETEROGENEOUS POROUS-MEDIA - PREDICTION AND UNCERTAINTY SO WATER RESOURCES RESEARCH LA English DT Article ID SUBSURFACE SOLUTE TRANSPORT; NATURAL GRADIENT EXPERIMENT; HEAD SPATIAL VARIABILITY; STEADY GROUNDWATER-FLOW; QUASI-LINEAR THEORY; STOCHASTIC-ANALYSIS; UNCONDITIONAL MOMENTS; EFFECTIVE RECHARGE; SAND AQUIFER; BORDEN SITE AB This study presents a method for obtaining risk-qualified estimates of various statistics that characterize the migration of a nonreactive tracer in heterogeneous porous media. The steps required to get these estimates are as follows: (1) the solute body is assumed to be composed of a large number of imaginary solute particles; (2) a Lagrangian description of the migration of the solute particles in space is adopted; (3) the Lagrangian description is transformed into an Eulerian one by a quasi-linear method, whereby the translation of the particles in space is simulated through successive, spatially correlated displacements; (4) the plume's various statistics are obtained by averaging over the ensemble of simulated particles, and, lastly, (5) simultaneous simulation of the motion of two particles in space entails the spatial moments of the plume and their variances, and in addition, the concentration is obtained qualified by its variance. The model is compared with numerical simulations and is found to compare quite favorably even for log conductivity variances as large as 2.6. This study shows that (1) after a certain travel time, the concentration variance becomes largest next to the plume center and gets smaller with distance from the plume center; (2) the concentration coefficient of variation grows with distance from the plume center and prediction of the low concentration on the periphery of the plume is subject to the largest uncertainty; (3) the concentration coefficient of variation grows with time while the concentration variance gets smaller with time; and (4) interpretation of field data depends on the interpolation method and in particular on the size of the averaging domain. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP RUBIN, Y (reprint author), UNIV CALIF BERKELEY,DEPT CIVIL ENGN,BERKELEY,CA 94720, USA. NR 30 TC 73 Z9 73 U1 0 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 JUL PY 1991 VL 27 IS 7 BP 1723 EP 1738 DI 10.1029/91WR00589 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA FV777 UT WOS:A1991FV77700033 ER PT J AU CREMERS, DA LEWIS, GK KORZEKWA, DR AF CREMERS, DA LEWIS, GK KORZEKWA, DR TI MEASUREMENT OF ENERGY DEPOSITION DURING PULSED LASER-WELDING SO WELDING JOURNAL LA English DT Article DE PULSED LASER WELDING; ENERGY DEPOSITION; INTERFEROMETER; LVDT; ND-YAG LASER; MEASUREMENT; THERMAL EXPANSION; THERMODYNAMICS; TRANSIENT EXPANSION; MELT DEPTH AB The energy deposited in small metal samples by Nd:YAG laser welding pulses (7.8 ms, 36 J/pulse max) was measured using an interferometer and a linear variable differential transformer (LVDT). These devices measured the expansion of a sample due to heating, which was used to calculate the absorbed laser pulse energy. These methods are simple and rapid compared to other techniques using calorimeters or thermocouples. The observed responses of the interferometer and LVDT compared closely with modeling calculations of heat flow and expansion. The effects of incident power density, surface condition, and atmosphere on energy absorption were investigated. Good correlation between deposited energy and melt depth in both the conduction and keyhole mode was obtained for samples of 1100 aluminum and 316 stainless steel. The results demonstrate these devices are useful to determine rapidly the melt depth without the time-consuming steps involved in metallographic cross-sectioning. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87544. RP CREMERS, DA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87544, USA. NR 18 TC 5 Z9 5 U1 1 U2 1 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 SN 0043-2296 J9 WELD J JI Weld. J. PD JUL PY 1991 VL 70 IS 7 BP S159 EP S167 PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA FU546 UT WOS:A1991FU54600015 ER PT J AU HUNTER, R AF HUNTER, R TI BROMUS INVASIONS ON THE NEVADA TEST SITE - PRESENT STATUS OF BRUBENS AND BTECTORUM WITH NOTES ON THEIR RELATIONSHIP TO DISTURBANCE AND ALTITUDE SO GREAT BASIN NATURALIST LA English DT Article DE BROMUS-RUBENS; BROMUS-TECTORUM; NEVADA TEST SITE; INTRODUCED SPECIES; FIRE PROPAGATION; FIRE RECOVERY AB Bromus rubens and Bromus tectorum are now nearly ubiquitous components of the Nevada Test Site (NTS) flora. Introduced to the western United States in the late 1800s, they spread through the Mojave and Great Basin deserts in the early twentieth century. Since quantitative studies began on the NTS in 1957, Bromus spp. have greatly increased in frequency and density. By 1988 both species occurred in many places at densities exceeding 1000 individuals per square meter. They may significantly increase flammability of the vegetation and reduce success of native ephemeral species. RP HUNTER, R (reprint author), US DOE,BASIC ENVIRONM COMPLIANCE & MONITORING PROGRAM,REYNOLDS ELECT & ENGN CO INC,LAS VEGAS,NV 89193, USA. NR 0 TC 51 Z9 54 U1 1 U2 9 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 JUN 30 PY 1991 VL 51 IS 2 BP 176 EP 182 PG 7 WC Ecology SC Environmental Sciences & Ecology GA GA419 UT WOS:A1991GA41900005 ER PT J AU STRASBURG, RF FRITZ, JS NAPLES, JO AF STRASBURG, RF FRITZ, JS NAPLES, JO TI LOW-CAPACITY LATEX-COATED RESINS FOR ANION CHROMATOGRAPHY SO JOURNAL OF CHROMATOGRAPHY LA English DT Article ID ION CHROMATOGRAPHY; EXCHANGE RESINS AB Methods are described for coating latexes bearing a quaternary ammonium group onto spherical, non-porous polymeric resins. Exchange capacity of the coated resins is controlled by the amount of acetonitrile in the coating slurry and on the amount of latex in the slurry. A capacity range of 11-85-mu-equiv./g was obtained. Excellent chromatographic separations were obtained with columns packed with the coated resins. Sulfate is shown to elute before bromide and nitrate. As much as 40% methanol can be incorporated into the eluent without damaging the chromatographic column. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. ROHM & HAAS CO,SPRING HOUSE,PA 19477. NR 10 TC 7 Z9 7 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD JUN 28 PY 1991 VL 547 IS 1-2 BP 11 EP 19 DI 10.1016/S0021-9673(01)88625-8 PG 9 WC Chemistry, Analytical SC Chemistry GA FV963 UT WOS:A1991FV96300002 ER PT J AU SELVIN, P AF SELVIN, P TI DOES THE HARRISON CASE REVEAL SEXISM IN MATH SO SCIENCE LA English DT Editorial Material RP SELVIN, P (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BIOPHYS,BERKELEY,CA 94720, USA. NR 0 TC 6 Z9 6 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 28 PY 1991 VL 252 IS 5014 BP 1781 EP 1783 DI 10.1126/science.252.5014.1781 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FU061 UT WOS:A1991FU06100011 PM 17753244 ER PT J AU SPARN, G THOMPSON, JD HUANG, SM KANER, RB DIEDERICH, F WHETTEN, RL GRUNER, G HOLCZER, K AF SPARN, G THOMPSON, JD HUANG, SM KANER, RB DIEDERICH, F WHETTEN, RL GRUNER, G HOLCZER, K TI PRESSURE-DEPENDENCE OF SUPERCONDUCTIVITY IN SINGLE-PHASE K3C60 SO SCIENCE LA English DT Article ID TEMPERATURE; C-60 AB The superconducting compound K3C60 (with transition temperature T(c) = 19.3 kelvin at ambient pressure), formed as a single phase by reaction of alkali vapor with solids of the icosahedral C60 Molecule (buckminsterfullerene), shows a very large decrease of T(c) with increasing pressure. Susceptibility measurements on sintered pellets showing bulk superconductivity arc reported up to 21 kilobars of pressure, where T(c) is already less than 8 kelvin. The results are consistent with a piling up of the density of states at the Fermi level. C1 UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,CTR SOLID STATE SCI,LOS ANGELES,CA 90024. RP SPARN, G (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Sparn, Guenter/F-5120-2013 NR 24 TC 163 Z9 163 U1 2 U2 17 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 28 PY 1991 VL 252 IS 5014 BP 1829 EP 1831 DI 10.1126/science.252.5014.1829 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FU061 UT WOS:A1991FU06100033 PM 17753258 ER PT J AU SIGMAN, ME CLOSS, GL AF SIGMAN, ME CLOSS, GL TI FREE-ENERGY AND STRUCTURE DEPENDENCE OF INTRAMOLECULAR TRIPLET ENERGY-TRANSFER IN ORGANIC-MODEL COMPOUNDS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON-TRANSFER REACTIONS; CHARGE-TRANSFER PERTURBATIONS; MATRIX ELEMENT CONTRIBUTIONS; MARCUS INVERTED REGION; LONG-RANGE ELECTRON; BIMOLECULAR REACTIONS; EXPERIMENTAL PROBES; EXCITED-STATES; MOLECULAR-STRUCTURES; RADICAL-ANIONS AB A series of compounds, each containing a triplet energy donor and an acceptor separated by a rigid spacer, has been designed and synthesized. The 1,4-cyclohexanediyl moiety is employed as the spacer for the series. The rates of intramolecular triplet energy transfer (TT) have been measured for the series. The rate of TT shows an inverted parabolic, i.e., Marcus, dependence on the thermodynamic driving force for a selected subset of the compounds wherein the donor is maintained constant throughout and the acceptors are "rigid", having no low-frequency internal degrees of freedom. The internal low-frequency torsional mode of a biphenylyl acceptor can be accounted for quite satisfactorily as an additional contribution to the solvent reorganization energy, lambda-s. The driving force dependence of the rate of TT is not modeled well by the conventional Marcus-Jortner equation for weakly coupled nonadiabatic electron transfer. Generalization of the Marcus-Jortner equation to include coupling to a high-frequency harmonic mode which is both displaced and distorted along the reaction coordinate provides a somewhat better fit to the experimental data with fewer adjustable parameters. C1 UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 41 TC 88 Z9 88 U1 0 U2 10 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 JUN 27 PY 1991 VL 95 IS 13 BP 5012 EP 5017 DI 10.1021/j100166a022 PG 6 WC Chemistry, Physical SC Chemistry GA FU291 UT WOS:A1991FU29100022 ER PT J AU LAWLESS, D SERPONE, N MEISEL, D AF LAWLESS, D SERPONE, N MEISEL, D TI ROLE OF OH. RADICALS AND TRAPPED HOLES IN PHOTOCATALYSIS - A PULSE-RADIOLYSIS STUDY SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID REFLECTANCE FLASH-PHOTOLYSIS; ELECTRON-PARAMAGNETIC-RES; TITANIUM-DIOXIDE; COLLOIDAL SEMICONDUCTORS; AQUEOUS-SOLUTION; HYDROXYL RADICALS; POSITIVE HOLES; SPIN-RESONANCE; TIO2 COLLOIDS; DEGRADATION AB The pulse radiolysis technique has been used to study the reaction of OH. radicals with 13-nm TiO2 particles. Hydroxyl radicals react with these particles in a near-diffusion-controlled rate. The hydroxyl is trapped on the TiO2 and exhibits a broad absorption band centered at about 350 nm. Oxygen has no effect on this reaction and its product characteristics. The product decays via first-order kinetics which are assigned to the collapse of two species trapped on the same particle to yield peroxides. The oxidative abilities of this product were confirmed by oxidation of SCN- to give the anion radical (SCN)2.-. The identity of the product of the OH. reaction with the particle is discussed and is identified as a trapped hole at the particle surface. Mechanistic implications to photocatalysis are emphasized; it is argued that the trapped hole and a surface-bound OH. radical are indistinguishable species. C1 CONCORDIA UNIV,DEPT CHEM,MONTREAL H3G 1M8,QUEBEC,CANADA. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 56 TC 319 Z9 322 U1 6 U2 57 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 JUN 27 PY 1991 VL 95 IS 13 BP 5166 EP 5170 DI 10.1021/j100166a047 PG 5 WC Chemistry, Physical SC Chemistry GA FU291 UT WOS:A1991FU29100047 ER PT J AU JOHNSTON, CT AGNEW, SF ECKERT, J JONES, LH SWANSON, BI UNKEFER, CJ AF JOHNSTON, CT AGNEW, SF ECKERT, J JONES, LH SWANSON, BI UNKEFER, CJ TI LOW-FREQUENCY SINGLE-CRYSTAL RAMAN, FAR-INFRARED, AND INELASTIC NEUTRON-SCATTERING STUDIES OF ACETANILIDE AT LOW-TEMPERATURE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID AMIDE-I BAND; VIBRATIONAL-SPECTRA; N-METHYLACETAMIDE; SOLITONS; DEPENDENCE; DEFECTS; PHONONS AB Single-crystal Raman, far-infrared (far-IR), and inelastic neutron scattering (INS) spectra of acetanilide (ACN) in the low-frequency region (20-200 cm-1) were obtained as a function of temperature. At 20 K, a total of 29 low-frequency Raman-active vibrational modes were resolved and assigned to a unique symmetry species. For comparison, a total of 23 far-IR bands were observed in the 20-200-cm-1 region at 20 K. Factor group analysis of ACN predicts 24 Raman-active and 15 IR-active phonon bands. The greater-than-expected number of observed bands in the low-frequency region was assigned to the presence of low-frequency internal modes that exhibit anomalous frequency-shift and line-narrowing behavior upon cooling. The most striking change occurs in the B1g (xy) polarization where a single band at 126 cm-1 at 305 K splits into three distinct, well-resolved bands at 133, 142, and 152 cm-1 at 20 K. INS spectra of ACN and its deuterated isotopomers demonstrate clearly that the 142-cm-1 band corresponds to a methyl torsion. In addition, low-frequency bands at 104 and 189 cm-1 were assigned to internal modes. In contrast to the phonon modes, the low-frequency internal modes all exhibit greater line broadening with temperature. C1 UNIV CALIF LOS ALAMOS SCI LAB,INC4,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,PLANSCE,LOS ALAMOS,NM 87545. RP JOHNSTON, CT (reprint author), UNIV FLORIDA,DEPT SOIL SCI,GAINESVILLE,FL 32611, USA. RI Johnston, Cliff/B-2215-2009 OI Johnston, Cliff/0000-0002-8462-9724 NR 26 TC 7 Z9 7 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 27 PY 1991 VL 95 IS 13 BP 5281 EP 5286 DI 10.1021/j100166a067 PG 6 WC Chemistry, Physical SC Chemistry GA FU291 UT WOS:A1991FU29100067 ER PT J AU MOONEY, B AF MOONEY, B TI SNOW WAY WITH CHOLERA SO NATURE LA English DT Letter RP MOONEY, B (reprint author), UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802, USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JUN 27 PY 1991 VL 351 IS 6329 BP 686 EP 686 DI 10.1038/351686d0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FU201 UT WOS:A1991FU20100028 PM 2062363 ER PT J AU SIMPSON, J TIMMERS, H RILEY, MA BENGTSSON, T BENTLEY, MA HANNA, F MULLINS, SM SHARPEYSCHAFER, JF WYSS, R AF SIMPSON, J TIMMERS, H RILEY, MA BENGTSSON, T BENTLEY, MA HANNA, F MULLINS, SM SHARPEYSCHAFER, JF WYSS, R TI COMPETING ANGULAR-MOMENTUM MECHANISMS AND NUCLEAR SHAPES AT HIGH-SPIN IN XE-122 SO PHYSICS LETTERS B LA English DT Article ID STRUCTURAL-CHANGES; ROTATIONAL BANDS; MASS REGION; DY-154; SPECTROSCOPY; ALIGNMENT; NEUTRON; YB-158; ER-158; BA-124 AB Discrete gamma-ray transitions have been observed up to spin approximately 30 in 122Xe. A dramatic change in the mechanism by which this nucleus generates angular momentum is observed to occur above spin 20. The collective rotation of a prolate nucleus is replaced at high spin by a regime of non-collective single-particle states. Particularly favoured states are observed at high spin and by comparison with the predictions of the cranked Nilsson and Woods-Saxon models specific single-particle configurations are suggested. This gives information on the spectrum of single-particle states and the active orbitals which build high angular momentum states in this mass region. C1 UNIV LIVERPOOL, OLIVER LODGE LAB, LIVERPOOL L69 3BX, ENGLAND. LUND INST TECHNOL, DEPT MATH PHYS, S-22100 LUND, SWEDEN. OAK RIDGE NATL LAB, JOINT INST HEAVY ION RES, OAK RIDGE, TN 37831 USA. RP SERC, DARESBURY LAB, WARRINGTON WA4 4AD, CHESHIRE, ENGLAND. NR 33 TC 30 Z9 30 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JUN 27 PY 1991 VL 262 IS 4 BP 388 EP 393 DI 10.1016/0370-2693(91)90610-3 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FV818 UT WOS:A1991FV81800003 ER PT J AU RUSSO, JG AF RUSSO, JG TI TOPOLOGICAL INVARIANTS IN NONCRITICAL STRING THEORIES SO PHYSICS LETTERS B LA English DT Article ID QUANTUM-GRAVITY; FIELD-THEORY; MODELS; 2D; ALGEBRA AB It is shown that 2D topological models can be interpreted as non-critical strings with some unusual BRST structure. The formalism permits to identify operators in these c < 1 string theories whose correlation functions are topological invariants. In some cases such operators belong to the usual physical space of the conformal theory. As an application, we analyse some minimal models coupled to gravity in the continuum approach and argue that the cases c = -2 and 0 correspond to topological theories. Finally we discuss a possible correspondence with the series of multi-critical points of the one-matrix model. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. RP RUSSO, JG (reprint author), STANFORD UNIV,DEPT PHYS,THEORY GRP,STANFORD,CA 94305, USA. OI Russo, Jorge Guillermo/0000-0002-3023-1833 NR 19 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 27 PY 1991 VL 262 IS 4 BP 411 EP 418 DI 10.1016/0370-2693(91)90614-V PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FV818 UT WOS:A1991FV81800007 ER PT J AU HO, CL HU, B YU, HL AF HO, CL HU, B YU, HL TI HIDDEN LOCAL SYMMETRY AND INDUCED TOPOLOGICAL TERMS SO PHYSICS LETTERS B LA English DT Article ID VECTOR-MESONS; SUPERCONDUCTIVITY; PARTICLES; MODEL AB Extending the previous derivation of an effective gauge theory from a generalized Nambu-Jona-Lasinio model, we show how the topological theta-term, theta-Tr F-approximately F, can be generated dynamically in a similar fashion. These results provide a vivid demonstration of hidden local symmetry at work. Possible phenomenological implications of this approach are also discussed. C1 UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. RP HO, CL (reprint author), ACAD SINICA,INST PHYS,TAIPEI 115,TAIWAN. NR 14 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 27 PY 1991 VL 262 IS 4 BP 455 EP 458 DI 10.1016/0370-2693(91)90621-V PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FV818 UT WOS:A1991FV81800014 ER PT J AU MOOKHTIAR, KA PELUSO, PS MULLER, DK DUNN, JJ COLEMAN, JE AF MOOKHTIAR, KA PELUSO, PS MULLER, DK DUNN, JJ COLEMAN, JE TI PROCESSIVITY OF T7 RNA-POLYMERASE REQUIRES THE C-TERMINAL PHE882-ALA883-COO- OR FOOT SO BIOCHEMISTRY LA English DT Article ID RIBONUCLEIC-ACID POLYMERASE; T7-RNA POLYMERASE; PROMOTER INTERACTIONS; TRANSCRIPTION; BACTERIOPHAGE-T7; BINDING; DNA; PURIFICATION AB The role of the C-terminal Phe882-Ala883 residues of bacteriophage T7 RNA polymerase in specific transcription has been investigated by means of site-directed mutagenesis. A mutant enzyme that lacks the C-terminal Phe882-Ala883 residues, denoted the "foot" mutant, has been cloned and overproduced, and the effects of the deletion on promoter recognition, initiation, and elongation have been determined. Gel retardation assays and DNase I footprinting show that the foot mutant specifically recognizes and binds to T7 promoters, although this binding appears to be approximately 30-fold weaker than that of the wild-type enzyme. Transcription assays using oligonucleotide templates that contain the consensus T7 promoter show a dramatic decrease in transcriptional activity for the foot mutant. With templates whose coding region begins CCC..., the mutant synthesizes poly(G) products even in the presence of all four nucleotides. The synthesis of poly(G) products from such templates has previously been observed for the wild-type enzyme when GTP is the sole nucleotide present in the reaction and is thought to occur by a novel mechanism involving slippage of the RNA chain 3' to 5' relative to the template [Martin, C. T., Muller, D. K., & Coleman, J. E. (1988) Biochemistry 27, 3966-3974]. These data suggest that the loss in transcriptional activity by the foot mutant results from a severe decrease in processivity as well as catalytic efficiency of the enzyme. Removal of the C-terminal Phe and Ala residues from the wild-type enzyme with carboxypeptidase A generates the phenotype of the mutant precisely, proving that all of the properties of the foot mutant derive from the loss of the Phe-Ala-COOH moiety. Protection of the C-terminal residues in the wild-type enzyme from hydrolysis by carboxypeptidase A in the presence of T7 promoter-containing DNA shows that these C-terminal residues may be intimately involved in the DNA - protein interactions, thereby explaining their crucial role in all phases of transcription. C1 YALE UNIV,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06510. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. FU NIGMS NIH HHS [GM 21919-16, 1-F32-GM14098] NR 19 TC 39 Z9 39 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 JUN 25 PY 1991 VL 30 IS 25 BP 6305 EP 6313 DI 10.1021/bi00239a032 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FT936 UT WOS:A1991FT93600032 PM 2059636 ER PT J AU CHIN, PKF MILLS, GL AF CHIN, PKF MILLS, GL TI KINETICS AND MECHANISMS OF KAOLINITE DISSOLUTION - EFFECTS OF ORGANIC-LIGANDS SO CHEMICAL GEOLOGY LA English DT Article ID FLUIDIZED-BED REACTOR; COORDINATION CHEMISTRY; ROOM-TEMPERATURE; SURFACE; MINERALS; SILICA; PRESSURE; ACIDS; SORPTION; ALUMINA AB The effect of protons, low molecular weight organic ligands, soil humic acid (HA), and stream water dissolved organic matter (DOM) on the rate of dissolution of kaolinite was examined. In acid solution (no ligands present) the rate of dissolution increased with increasing [H+] and the rate of Si dissolution was generally faster than Al. Low molecular weight organic ligands markedly increased the dissolution rates of both Al and Si in the following order: oxalate > malonate almost-equal-to salicylate > o-phthalate. In the presence of organic ligands, the rate of Al dissolution was generally much greater than Si. Soil HA and stream water DOM did not promote the dissolution of kaolinite under the experimental conditions examined in this study. The dissolution kinetics of Al were interpreted in terms of a surface complexation model and the rate equations described in terms of the concentrations of specific (i.e. inner sphere) surface complexes. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29801. RP CHIN, PKF (reprint author), FAIRLEIGH DICKINSON UNIV,TEANECK,NJ 07666, USA. NR 50 TC 61 Z9 68 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JUN 25 PY 1991 VL 90 IS 3-4 BP 307 EP 317 DI 10.1016/0009-2541(91)90106-2 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX144 UT WOS:A1991FX14400009 ER PT J AU PERRY, SE BUVINGER, WE BENNETT, J KEEGSTRA, K AF PERRY, SE BUVINGER, WE BENNETT, J KEEGSTRA, K TI SYNTHETIC ANALOGS OF A TRANSIT PEPTIDE INHIBIT BINDING OR TRANSLOCATION OF CHLOROPLASTIC PRECURSOR PROTEINS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID IMPORT RECEPTOR; SMALL SUBUNIT; RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE; ENVELOPE MEMBRANE; MITOCHONDRIAL; TRANSPORT; SEQUENCES; SITE; IDENTIFICATION; AMPHIPHILICITY AB Although amino-terminal transit peptides of chloroplastic precursor proteins are known to be necessary and sufficient for import into chloroplasts, the mechanism by which they mediate this process is not understood. Another important question is whether different precursors share a common transport apparatus. We used 20-residue synthetic peptides corresponding to regions of the transit peptide of the precursor to the small subunit of ribulose bisphosphate carboxylase (prSS) as competitive inhibitors for the binding and translocation of precursor proteins into chloroplasts. Synthetic peptides with sequences corresponding to either end of the transit peptide had little to no effect on binding of prSS to chloroplasts, but significantly inhibited its translocation. Synthetic peptides corresponding to the central region of the transit peptide inhibited binding of prSS to chloroplasts. Each of the peptides inhibited binding or translocation of precursors to light-harvesting chlorophyll a/b protein, ferredoxin, and plastocyanin in the same manner and to a similar extent as prSS transport was inhibited. The results presented in this paper suggest that the central regions of the transit peptide of prSS mediate binding to the chloroplastic surface, whereas the ends of this transit peptide are more important for translocation across the envelope. Furthermore, all of the precursors tested appear to share components in the transport apparatus even though they are sorted to different chloroplastic compartments. C1 UNIV WISCONSIN,DEPT BOT,MADISON,WI 53706. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RI Perry, Sharyn/M-9177-2013 OI Perry, Sharyn/0000-0002-3011-8240 NR 45 TC 55 Z9 55 U1 0 U2 2 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUN 25 PY 1991 VL 266 IS 18 BP 11882 EP 11889 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FT762 UT WOS:A1991FT76200072 PM 2050684 ER PT J AU LOWNEY, P CORRAL, J DETMER, K LEBEAU, MM DEAVEN, L LAWRENCE, HJ LARGMAN, C AF LOWNEY, P CORRAL, J DETMER, K LEBEAU, MM DEAVEN, L LAWRENCE, HJ LARGMAN, C TI A HUMAN HOX-1 HOMEOBOX GENE EXHIBITS MYELOID-SPECIFIC EXPRESSION OF ALTERNATIVE TRANSCRIPTS IN HUMAN HEMATOPOIETIC-CELLS SO NUCLEIC ACIDS RESEARCH LA English DT Article ID DNA-BINDING DOMAIN; SYNERGISTIC ACTIVATION; SORTED CHROMOSOMES; CONTAINING PROTEIN; DROSOPHILA; DISTINCT; ACID AB As part of a survey of the expression of homeobox-containing genes in human hematopoietic cells, we identified a novel gene (PL1) expressed only in cells of the myelomonocytic lineage (Shen et al., Proc. Natl. Acad. Sci, USA 86, 8536, 1989). On Northern gel analysis, major transcripts of 3.0 and 2.2 kb length are observed. Alternatively spliced homeobox-containing cDNAs, corresponding to the major transcripts, have been cloned from two myeloid leukemia cell libraries. The two cDNAs share the homeodomain and 3' flanking region but have unique 5' flanking regions. The longer transcript, would encode a 496 amino acid homeobox-containing protein, while the shorter message would encode a 94 amino acid homeobox-containing protein lacking the extended amino-terminal region. These two transcripts are differentially expressed in human leukemia cell lines. The larger transcript is exclusively expressed in cells with myelomonocytic features, while the smaller transcript is expressed in a variety of hematopoietic cell types. PL mRNA is also detectable in normal human bone marrow by RNAse protection. Neither transcript is expressed in uninduced teratocarcinoma cells or in the adult human tissues surveyed. The homeodomain is identical to the genomic sequence for Hox 1H, a newly identified member of the Hox 1 locus (Acampora et al. Nucl. Acids Res. 17, 10385, 1989). The PL1 gene was localized to chromosome 7 using chromosome specific blots and sublocalized to region p14 - 21 by in situ hybridization of chromosomal spreads, confirming its location within the Hox 1 complex. C1 VET ADM MED CTR,DEPT MED,RES 151,150 MUIR RD,MARTINEZ,CA 94553. UNIV CALIF DAVIS,DEPT INTERNAL MED,DAVIS,CA 95616. UNIV CHICAGO,HEMATOL ONCOL SECT,CHICAGO,IL 60637. UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. FU NCI NIH HHS [CA 40064, CA 47866] NR 31 TC 74 Z9 76 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD JUN 25 PY 1991 VL 19 IS 12 BP 3443 EP 3449 DI 10.1093/nar/19.12.3443 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FU512 UT WOS:A1991FU51200039 PM 1676505 ER PT J AU HOHIMER, JP CRAFT, DC VAWTER, GA MYERS, DR AF HOHIMER, JP CRAFT, DC VAWTER, GA MYERS, DR TI NEAR-DIFFRACTION-LIMITED ANGLE-SWITCHABLE OUTPUT BEAM FROM A BROAD-AREA DIODE-LASER WITH AN INTRACAVITY SPATIAL PHASE CONTROLLER SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR-LASERS; HIGH-POWER; ARRAYS; CAVITY AB The production of a near-diffraction-limited single-lobed angle-switchable output beam from a broad-area diode laser with an intracavity spatial phase controller is demonstrated. This 100-mu-m-wide broad-area laser produces a 0.8-degrees full width at half maximum output beam at single-facet pulsed powers of > 300 mW. The spatial phase controller operates in two distinct modes (thermal and gain), providing beam scanning over 1.4-degrees and beam switching of 8-degrees. The phase controller also permits a dynamic study of the effect of wavefront tilt on device coupling and phasing. RP HOHIMER, JP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 16 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 24 PY 1991 VL 58 IS 25 BP 2886 EP 2888 DI 10.1063/1.104737 PG 3 WC Physics, Applied SC Physics GA FT115 UT WOS:A1991FT11500006 ER PT J AU GARBAUSKAS, MF ARENDT, RH JORGENSEN, JD HITTERMAN, RL AF GARBAUSKAS, MF ARENDT, RH JORGENSEN, JD HITTERMAN, RL TI HIGH-TEMPERATURE NEUTRON-DIFFRACTION STUDY OF THE MELTING BEHAVIOR OF BI2CASR2CU2OX SO APPLIED PHYSICS LETTERS LA English DT Article AB High-temperature neutron powder diffraction has been used to study the melting, and subsequent reformation, behavior of Bi2CaSr2Cu2O(x) (2122), the 80 K transition temperature oxide superconductor. It was found that the (2122) substantially reforms upon return to a temperature just below the peritectic melting point of the material. This finding implies that difficulties encountered in melt processing this material may be due largely to gross segregation of the constituents while the material is partially molten, as opposed to slow formation kinetics for this species. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP GARBAUSKAS, MF (reprint author), GE,CORP RES & DEV,SCHENECTADY,NY 12301, USA. NR 5 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 24 PY 1991 VL 58 IS 25 BP 2987 EP 2988 DI 10.1063/1.105226 PG 2 WC Physics, Applied SC Physics GA FT115 UT WOS:A1991FT11500040 ER PT J AU CHENG, SZD ZHANG, AQ BARLEY, JS CHEN, JH HABENSCHUSS, A ZSCHACK, PR AF CHENG, SZD ZHANG, AQ BARLEY, JS CHEN, JH HABENSCHUSS, A ZSCHACK, PR TI ISOTHERMAL THICKENING AND THINNING PROCESSES IN LOW-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) FRACTIONS .1. FROM NONINTEGRAL-FOLDING TO INTEGRAL-FOLDING CHAIN CRYSTAL TRANSITIONS SO MACROMOLECULES LA English DT Article ID SINGLE-CRYSTALS; LONG PARAFFINS; CRYSTALLIZATION; MORPHOLOGY; GROWTH; MELT AB On the basis of time-resolved synchrotron small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) experiments, a nonintegral-folding chain (NIF) crystal can be found in low molecular weight poly(ethylene oxide) (PEO) fractions. This crystal grows first as a transient state, and integral-folding chain (IF) crystals form later through an isothermal thickening or thinning process. In a PEO fraction with MW = 4250, it is observed that either isothermal thickening to the IF (n = 0) crystal or thinning to the IF(n = 1) crystal occurs depending upon the thermodynamic stability of the NIF crystal. At low crystallization temperatures, the main process is isothermal thinning; at intermediate temperatures, both thickening and thinning processes are observed; only isothermal thickening can be seen at high temperatures. This observation indicates that the NIF crystal exists as an initial step of the crystal growth over a wide crystallization temperature range. The fold length of this NIF crystal is crystallization temperature dependent, a behavior similar to the observed changes of fold length of polymer lamellar crystals. Systematic study in changes of fold length from the NIF to IF crystals with the time has resulted in a kinetic map of such transitions. This process is related to the chain molecular motion along the crystallographic c-axis in the solid state. C1 UNIV AKRON,COLL POLYMER SCI & POLYMER ENGN,DEPT POLYMER SCI,AKRON,OH 44325. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP CHENG, SZD (reprint author), UNIV AKRON,COLL POLYMER SCI & POLYMER ENGN,INST POLYMER SCI,AKRON,OH 44325, USA. NR 31 TC 88 Z9 91 U1 2 U2 24 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 24 PY 1991 VL 24 IS 13 BP 3937 EP 3944 DI 10.1021/ma00013a030 PG 8 WC Polymer Science SC Polymer Science GA FT906 UT WOS:A1991FT90600030 ER PT J AU BARPELED, O GROSSISSEROFF, R BENHUR, H HOSKINS, I GRONER, Y BIEGON, A AF BARPELED, O GROSSISSEROFF, R BENHUR, H HOSKINS, I GRONER, Y BIEGON, A TI FETAL HUMAN BRAIN EXHIBITS A PRENATAL PEAK IN THE DENSITY OF SEROTONIN 5-HT1A RECEPTORS SO NEUROSCIENCE LETTERS LA English DT Article DE 5-HT1A RECEPTOR; FETAL HUMAN BRAIN; DOWNS SYNDROME ID TRANSIENT EXPRESSION; POSTMORTEM; BINDING; NEURONS; GROWTH; AREAS AB High densities of serotonergic 5-HT1A receptors, in excess of adult levels, were found in the human fetal brain between the 16th and 22nd weeks of gestation. 5-HT1A receptors were measured by quantitative autoradiography using brain sections of fetuses aborted at gestational ages 16-22 weeks. The highest receptor concentrations were detected in the cortex and hippocampus. Two brains obtained from fetuses with Down's syndrome at 22 and 24 weeks gestation exhibited abnormal receptor levels compared to age matched controls. The presence of an early, prenatal peak of 5-HT1A receptors in fetal cortex and hippocampus suggests that these receptors play a role in human brain development and may also be involved in developmental disorders such as Down's syndrome. C1 WEIZMANN INST SCI,DEPT NEUROBIOL,IL-76100 REHOVOT,ISRAEL. KAPLAN HOSP,IL-76100 REHOVOT,ISRAEL. NYU MED CTR,DEPT OBSTET & GYNECOL,NEW YORK,NY 10016. LAWRENCE KERLELEY LAB,DIV RES MED & RADIAT BIOPHYS,BERKELEY,CA. RP BARPELED, O (reprint author), WEIZMANN INST SCI,DEPT MOLEC GENET & VIROL,IL-76100 REHOVOT,ISRAEL. FU NICHD NIH HHS [HD21229] NR 23 TC 89 Z9 90 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0304-3940 J9 NEUROSCI LETT JI Neurosci. Lett. PD JUN 24 PY 1991 VL 127 IS 2 BP 173 EP 176 DI 10.1016/0304-3940(91)90787-T PG 4 WC Neurosciences SC Neurosciences & Neurology GA FV370 UT WOS:A1991FV37000007 PM 1831889 ER PT J AU BERENDS, FA KUIJF, H TAUSK, B GIELE, WT AF BERENDS, FA KUIJF, H TAUSK, B GIELE, WT TI ON THE PRODUCTION OF A W AND JETS AT HADRON COLLIDERS SO NUCLEAR PHYSICS B LA English DT Article ID TEVATRON COLLIDER; PARTON PROCESSES; HEAVY QUARKS; SEARCH; FERMILAB; EVENTS AB In this paper the evaluation of matrix elements for a vector boson decaying into n partons (n less-than-or-equal-to 6) is presented. For this purpose recursive techniques and Weyl-van der Waerden spinor calculus are used. By appropriately crossing partons the amplitudes can be used to describe the production of a W and jets. The four-jet case is of particular interest as background to interesting physics signals. Numerical results are given for present and future accelerator energies. Also the signal versus background question for top quark search is briefly discussed. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP BERENDS, FA (reprint author), LEIDEN UNIV,INST LORENTZ,POB 9506,2312 AV LEIDEN,NETHERLANDS. NR 21 TC 228 Z9 228 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD JUN 24 PY 1991 VL 357 IS 1 BP 32 EP 64 DI 10.1016/0550-3213(91)90458-A PG 33 WC Physics, Particles & Fields SC Physics GA FR443 UT WOS:A1991FR44300002 ER PT J AU YANG, LH FONG, CY NICHOLS, CS AF YANG, LH FONG, CY NICHOLS, CS TI IMPURITY-DEFECT COMPLEXES AND DOPING MECHANISM IN A-SI-H SO PHYSICAL REVIEW LETTERS LA English DT Article ID HYDROGENATED AMORPHOUS-SILICON; DOPANT STATES; PSEUDOPOTENTIALS; DENSITY AB The most outstanding feature observed for dopants in hydrogenated amorphous silicon - a shift in the Fermi level accompanied by an increase in the charged-defect density - has previously been postulated to stem from the formation of substitutional-dopant-dangling-bond complexes. Using first-principles self-consistent pseudopotential calculations in conjunction with a supercell model for the amorphous network and the ability of network relaxation from the first-principles results, we have studied the electronic and structural properties of substitutional fourfold-coordinated phosphorus and boron at the second-neighbor position to a dangling-bond defect. We demonstrate that such impurity-defect complexes can account for the general features observed experimentally. C1 ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. UNIV CALIF DAVIS, DEPT PHYS, DAVIS, CA 95616 USA. CORNELL UNIV, DEPT MAT SCI & ENGN, ITHACA, NY 14853 USA. NR 22 TC 13 Z9 14 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 24 PY 1991 VL 66 IS 25 BP 3273 EP 3276 DI 10.1103/PhysRevLett.66.3273 PG 4 WC Physics, Multidisciplinary SC Physics GA FT113 UT WOS:A1991FT11300012 ER PT J AU HILL, JP THURSTON, TR ERWIN, RW RAMSTAD, MJ BIRGENEAU, RJ AF HILL, JP THURSTON, TR ERWIN, RW RAMSTAD, MJ BIRGENEAU, RJ TI TRANSITION TO LONG-RANGE ORDER IN THE 3-DIMENSIONAL RANDOM-FIELD ISING-MODEL SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY SCATTERING; PHASE-TRANSITIONS; SYSTEMS; BEHAVIOR AB We report both synchrotron-x-ray and neutron-diffraction studies of the magnetic ordering in a crystal of Mn0.75Zn0.25F2 in a magnetic field. The neutron experiments reproduce previous results showing the establishment of a short-range domain state on cooling in a field. Remarkably, the magnetic x-ray scattering shows that within a few microns of the surface there is a second-order transition to true long-range order on field cooling. Implications of these results are discussed. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP HILL, JP (reprint author), MIT,DEPT PHYS,CAMBRIDGE,MA 02139, USA. RI Hill, John/F-6549-2011 NR 20 TC 48 Z9 48 U1 2 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 24 PY 1991 VL 66 IS 25 BP 3281 EP 3284 DI 10.1103/PhysRevLett.66.3281 PG 4 WC Physics, Multidisciplinary SC Physics GA FT113 UT WOS:A1991FT11300014 ER PT J AU BEYERMANN, WP HUNDLEY, MF CANFIELD, PC THOMPSON, JD FISK, Z SMITH, JL SELSANE, M GODART, C LATROCHE, M AF BEYERMANN, WP HUNDLEY, MF CANFIELD, PC THOMPSON, JD FISK, Z SMITH, JL SELSANE, M GODART, C LATROCHE, M TI HEAVY-ELECTRON ANTIFERROMAGNETISM IN CEPT2SN2 SO PHYSICAL REVIEW LETTERS LA English DT Article ID KONDO LATTICE; SUSCEPTIBILITY AB We have measured specific heat, magnetic susceptibility, and resistivity on the cerium-intermetallic compound CePt2Sn2. The heat capacity shows a strong increase below a few kelvin, typical of a large many-body enhancement of the density of states or equivalently of the effective electronic mass. Just before the material orders antiferromagnetically at T(N) = 0.88 K, the linear temperature coefficient of the specific heat-gamma is approximately 3.5 J/mole K2, making this material one of the heaviest electron systems known. The low Neel temperature and huge specific heat imply similarly low energy scales for competing RKKY and Kondo-like interactions. C1 CNRS,CHIM MET TERRES RARES LAB,F-92190 MEUDON,FRANCE. RP BEYERMANN, WP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Canfield, Paul/H-2698-2014; LATROCHE, MICHEL/L-6254-2014 OI LATROCHE, MICHEL/0000-0002-8677-8280 NR 21 TC 38 Z9 38 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 24 PY 1991 VL 66 IS 25 BP 3289 EP 3292 DI 10.1103/PhysRevLett.66.3289 PG 4 WC Physics, Multidisciplinary SC Physics GA FT113 UT WOS:A1991FT11300016 ER PT J AU BLATTER, G GESHKENBEIN, VB VINOKUR, VM AF BLATTER, G GESHKENBEIN, VB VINOKUR, VM TI QUANTUM COLLECTIVE CREEP SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC; SUPERCONDUCTORS AB We study the phenomenon of quantum creep in bulk superconductors within the framework of weak-collective-pinning theory. Single-vortex pinning at moderate magnetic fields as well as creep of vortex bundles at high fields are discussed for the case of current densities near critical. In the limit of strong dissipation and for moderate magnetic fields the basic parameter determining the tunneling rate is the ratio rho-n/xi (rho-n = normal-state resistivity, xi = coherence length), with strong tunneling realized for rho-n/xi greater-than-or-similar-to 1 k-OMEGA. C1 ASEA BROWN BOVERI,CORP RES,CH-5405 BADEN,SWITZERLAND. LD LANDAU THEORET PHYS INST,MOSCOW 117940,USSR. ARGONNE NATL LAB,ARGONNE,IL 60439. RP BLATTER, G (reprint author), SWISS FED INST TECHNOL,CH-8093 ZURICH,SWITZERLAND. NR 20 TC 167 Z9 167 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 24 PY 1991 VL 66 IS 25 BP 3297 EP 3300 DI 10.1103/PhysRevLett.66.3297 PG 4 WC Physics, Multidisciplinary SC Physics GA FT113 UT WOS:A1991FT11300018 ER PT J AU FEINGOLD, M GONZALEZ, DL MAGNASCO, MO PIRO, O AF FEINGOLD, M GONZALEZ, DL MAGNASCO, MO PIRO, O TI ON THE UNIVERSALITY CLASS DEPENDENCE OF PERIOD DOUBLING INDEXES SO PHYSICS LETTERS A LA English DT Article ID NON-LINEAR TRANSFORMATIONS; ORDER AB The dependence on nu of the period doubling scaling indices for unimodal maps with a critical point of the form (x)nu is numerically investigated. A new symbolic dynamics based computation technique working in configuration space is introduced. The existence of an upper bound for delta(nu --> infinity) is numerically verified. An accurate estimate of 29.8 is given for this limit. Moreover, the global functional form of delta(nu) is shown to have an interesting symmetry. C1 UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. NATL UNIV LA PLATA,DEPT FIS,RA-1900 LA PLATA,ARGENTINA. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87544. RP FEINGOLD, M (reprint author), UNIV CAMBRIDGE,CAVENDISH LAB,CAMBRIDGE CB3 0HE,ENGLAND. RI Gonzalez, Diego Luis/D-2280-2010; Feingold, Mario/F-1400-2012 OI Gonzalez, Diego Luis/0000-0001-9646-9900; Feingold, Mario/0000-0001-9316-5856 NR 15 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUN 24 PY 1991 VL 156 IS 6 BP 272 EP 276 DI 10.1016/0375-9601(91)90173-6 PG 5 WC Physics, Multidisciplinary SC Physics GA FW446 UT WOS:A1991FW44600004 ER PT J AU BAUMANN, G AF BAUMANN, G TI INTEGRABILITY AND CHAOS FOR 2 COPROPAGATING PULSES IN OPTICAL FIBERS SO PHYSICS LETTERS A LA English DT Article ID COMPLEX GINZBURG-LANDAU; PAINLEVE PROPERTY; EQUATIONS; TRANSFORMATIONS AB We demonstrate that a coupled system of nonlinear Schrodinger equations describing copropagating pulses in optical fibers are integrable for certain values of the coupling constants. To determine the integrable cases we used a Painleve test. For other choices of the coupling parameters we found chaos of a Hamiltonian system. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUN 24 PY 1991 VL 156 IS 6 BP 298 EP 302 DI 10.1016/0375-9601(91)90177-A PG 5 WC Physics, Multidisciplinary SC Physics GA FW446 UT WOS:A1991FW44600008 ER PT J AU NEUHAUSER, D JUDSON, R PERSKI, A AF NEUHAUSER, D JUDSON, R PERSKI, A TI INELASTIC PROBABILITIES ABOVE THE 3-BODY BREAKUP THRESHOLD VIA A PROJECTION OPERATOR-FORMALISM SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; QUANTUM-MECHANICAL CALCULATION; POTENTIAL-ENERGY SURFACE; S-MATRIX ELEMENTS; REACTIVE SCATTERING; MOLECULAR-DYNAMICS; COLLISIONS; SYSTEM; H+H-2; H-3 AB Inelastic scattering probabilities are presented for the H + H-2 reaction (collinear and J = O) at energies near and above the breakup threshold. The simulations are performed in the time-dependent projection-operator formalism, which is very efficient due to the use of a single (reagents) coordinate system for the full wavefunction. C1 SANDIA NATL LABS,CTR COMPUTAT ENGN,LIVERMORE,CA 94550. BAR ILAN UNIV,DEPT CHEM,RAMAT GAN,ISRAEL. RP NEUHAUSER, D (reprint author), PRINCETON UNIV,DEPT CHEM,PRINCETON,NJ 08544, USA. OI Judson, Richard/0000-0002-2348-9633 NR 26 TC 6 Z9 6 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 JUN 21 PY 1991 VL 181 IS 2-3 BP 151 EP 156 DI 10.1016/0009-2614(91)90347-C PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FU295 UT WOS:A1991FU29500010 ER PT J AU FRITZ, JS AF FRITZ, JS TI PRINCIPLES AND APPLICATIONS OF ION-EXCLUSION CHROMATOGRAPHY SO JOURNAL OF CHROMATOGRAPHY LA English DT Article; Proceedings Paper CT 1990 INTERNATIONAL ION CHROMATOGRAPHY SYMP CY SEP 30-OCT 03, 1990 CL SAN DIEGO, CA SP DIONEX, MILLIPORE, DIV WATER CHROMATOG ID ELECTROCHEMICAL DETECTION; CONDUCTIVITY DETECTION; COULOMETRIC DETECTION; CARBOXYLIC-ACIDS; EXCHANGE; WATER; COLUMN; ENHANCEMENT; SEPARATION; SAMPLES AB Ion-exclusion chromatography is a relatively old technique that has been attracting increased attention. It is particularly useful for separating hydrophilic molecular species from one another and from large amounts of ionic materials. The basic principles and methodology of ion-exclusion chromatography are presented and illustrated with typical examples. Several recent developments in ion-exclusion chromatography are discussed. These include methods for the enhancement of conductivity detection of weakly ionized substances and a new method for the chromatographic separation and detection of water. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP FRITZ, JS (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 35 TC 47 Z9 47 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR PD JUN 21 PY 1991 VL 546 IS 1-2 BP 111 EP 118 DI 10.1016/S0021-9673(01)93010-9 PG 8 WC Chemistry, Analytical SC Chemistry GA FV829 UT WOS:A1991FV82900010 ER PT J AU GLASS, JD AF GLASS, JD TI A SEQUENCE RELATED TO THE HUMAN GONADOLIBERIN PRECURSOR NEAR THE N-TERMINI OF HIV AND SIV GAG POLYPROTEINS SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article ID HORMONE-RELEASING HORMONE; LUTEINIZING-HORMONE; T4 ANTIGEN; VIRUS; RECEPTOR; RETROVIRUS; EXPRESSION; INFECTION; DECLINE; THYMUS C1 CUNY BROOKLYN COLL,INST APPL SCI,ENVIRONM SCI LAB,BROOKLYN,NY 11210. RP GLASS, JD (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 30 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-5193 J9 J THEOR BIOL JI J. Theor. Biol. PD JUN 21 PY 1991 VL 150 IS 4 BP 489 EP 496 DI 10.1016/S0022-5193(05)80442-4 PG 8 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA FT859 UT WOS:A1991FT85900006 PM 1943131 ER PT J AU LANDRY, MJ RUPERT, JW MITTAS, A AF LANDRY, MJ RUPERT, JW MITTAS, A TI COUPLING OF HIGH-POWER LASER DIODE OPTICAL POWER SO APPLIED OPTICS LA English DT Article AB This paper describes the characteristics of optical couplers with high power laser diodes as sources. The couplers investigated include gradient-index (GRIN) lenses manufactured by Nippon Sheet Glass, a plano-convex lens, a prism, optical fibers manufactured by Ensign-Bickford and Nippon Sheet Glass, and fiber optic stub manufacture by Spec Tran. The characteristics measured included: (1) GRIN lens transmission of up to 97%, fiber transmission of up to 90%, plano-convex lens transmission of up to 92%; (2) intensity distribution contours and profiles of the beam transmitted through GRIN lenses and optical fibers; (3) the beam dimensions of a collimating system; and (4) the divergence of optical fibers of varying lenghts. Spectra Diode Laboratory and McDonnell Astronautics Company/Opto Electronics Center manufactured the laser diodes sources that emitted up to 3.6 W. C1 SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. RP LANDRY, MJ (reprint author), SCOT INC, 2525 CURTISS ST, DOWNERS GROVE, IL 60515 USA. NR 21 TC 4 Z9 5 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1991 VL 30 IS 18 BP 2514 EP 2526 PG 13 WC Optics SC Optics GA FR740 UT WOS:A1991FR74000018 PM 20700239 ER PT J AU SAEED, M KIM, D DIMAURO, LF AF SAEED, M KIM, D DIMAURO, LF TI OPTIMIZATION AND CHARACTERIZATION OF A HIGH REPETITION RATE, HIGH-INTENSITY ND-YLF REGENERATIVE AMPLIFIER (REPRINTED FROM APPLIED OPTICS, VOL 29, PG 1752-1757, 1990) SO APPLIED OPTICS LA English DT Reprint ID YAG LASER; PULSES; AMPLIFICATION; KHZ AB Solid state regenerative amplifiers have proved to be a reliable source for producing stable millijoule pulses as short as a few picoseconds at repetition rates ranging from a few hertz to several kilohertz. Here we report on the operation of a cw pumped Nd:YLF regenerative amplifier that uses a convex-concave design to optimize output energy and stability while minimizing the energy density on critical intracavity optical components. The amplifier yields stable 5-mJ 40-ps pulses at 700 Hz and has achieved 1-mJ output at a 3.5-kHz repetition rate. Results and analysis of the beam profile and contrast ratio for this system are also presented. Our results are contrasted to the general design considerations of regenerative amplifiers. RP SAEED, M (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 20 TC 0 Z9 0 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1991 VL 30 IS 18 BP 2527 EP 2532 PG 6 WC Optics SC Optics GA FR740 UT WOS:A1991FR74000019 PM 20700240 ER PT J AU VITELLO, P DERMER, CD AF VITELLO, P DERMER, CD TI A THEORY OF GAMMA-RAY BURSTS BASED ON RESONANT COMPTON-SCATTERING SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, BURSTS; RADIATION MECHANISMS; STARS, MAGNETIC; STARS, NEUTRON ID STRONG MAGNETIC-FIELDS; NEUTRON STARS; RELATIVISTIC PLASMAS; ANNIHILATION LINES; PAIR ANNIHILATION; SPECTRA; EMISSION; CYCLOTRON; ABSORPTION; RADIATION AB We calculate photon spectra produced from the resonant Compton scattering of blackbody photons by a beam of energetic electrons and positrons. The beam is assumed to be directed radially outward along the magnetic axis of a highly magnetized neutron star. We assume a dipole magnetic field geometry and include the effects of Compton-scattering energy losses on the particles in the beam during transport. A range of surface temperatures near 1 keV and magnetic field strengths near 10(12) G are studied for monoenergetic and power-law electron and positron source functions. Photon spectra similar to observed gamma-ray burst spectra are obtained for power-law beam injection functions with low-energy cutoffs, provided that (1) a large fraction of the neutron star is radiating and that (2) the particles in the beam lose most of their energy close to the neutron-star surface. We therefore propose that gamma-ray bursts are the resonant scattered emission of electron-positron pairs injected very close to the surface of a neutron star. The pairs are produced with a roughly power-law spectrum above a cutoff electron Lorentz factor-gamma* almost-equal-to 5-10. After injection, the electrons and positrons lose energy by Compton scattering blackbody photons and rescattering the nonthermal resonance emission. Depending on the temperature and magnetic field, the mean free path for energy loss can be a fraction of the neutron star radius, so that the pairs slow down to directed energies of almost-equal-to 20-50 keV and random energies in the outflowing fluid frame on the order of the cyclotron energy. If the injection rate is great enough, the bulk of the pairs annihilate and produce a narrow pair annihilation line. The cyclotron features observed in gamma-ray burst spectra are due to complicated radiative transfer effects of photons with energies near the cyclotron fundamental and higher harmonics, whose escape from the outflowing plasma is strongly modulated by the angle- and energy-dependent resonant Compton-scattering opacity. C1 UNIV CALIF BERKELEY, SPACE SCI LAB, BERKELEY, CA 94720 USA. RP VITELLO, P (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DEPT PHYS, POB 808, L-296, LIVERMORE, CA 94550 USA. NR 68 TC 10 Z9 10 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1991 VL 374 IS 2 BP 668 EP 686 DI 10.1086/170152 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FR742 UT WOS:A1991FR74200022 ER PT J AU KETO, E JERNIGAN, G BALL, R ARENS, J MEIXNER, M AF KETO, E JERNIGAN, G BALL, R ARENS, J MEIXNER, M TI HIGH ANGULAR RESOLUTION BROAD-BAND IMAGING IN THE MIDINFRARED - THE INFRARED BRIGHT GALAXY NGC-34 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, GENERAL; GALAXIES, INDIVIDUAL (NGC-34) ID IRAS AB We report on a high angular resolution (1") mid-IR image of the IR-bright galaxy NGC 34. The observation shows the mid-IR emission to be very compact, less-than-or-equal-to 2.3" x 1.7" (less-than-or-equal-to 870 x 640 pc, D = 78 Mpc, H0 = 75 km s-1 Mpc-1). This and previous observations indicate sizes smaller than predicted by starburst models for the emission. The achieved sensitivity, 15 mJy minutes-1/2 arcsec-2, (1-sigma NEFD DELTA-lambda = 5-mu-m) is the highest sensitivity ever obtained for any observation with a mid-IR array camera. C1 UNIV HAWAII,NASA INFRARED TELESCOPE FACIL,HONOLULU,HI 96822. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. RP KETO, E (reprint author), UNIV ILLINOIS,ASTRON IMAGING LAB,1002 W GREEN ST,URBANA,IL 61801, USA. NR 7 TC 8 Z9 8 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 JUN 20 PY 1991 VL 374 IS 2 BP L29 EP L31 DI 10.1086/186064 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FR745 UT WOS:A1991FR74500001 ER PT J AU LEDERER, H MORTENSEN, K MAY, RP BAER, G CRESPI, HL DERSCH, D HEUMANN, H AF LEDERER, H MORTENSEN, K MAY, RP BAER, G CRESPI, HL DERSCH, D HEUMANN, H TI SPATIAL ARRANGEMENT OF SIGMA-FACTOR AND CORE ENZYME OF ESCHERICHIA-COLI RNA-POLYMERASE - A NEUTRON SOLUTION SCATTERING STUDY SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA POLYMERASE; NEUTRON SCATTERING; SIGMA FACTOR; DEUTERATION ID SMALL-ANGLE SCATTERING; X-RAY; NUCLEOTIDE-SEQUENCE; DNA; SUBUNIT; HOLOENZYME; PROMOTER; COMPLEX; GENE; TRANSCRIPTION C1 MAX PLANCK INST BIOCHEM,W-8033 MARTINSRIED,GERMANY. RISO NATL LAB,DK-4000 ROSKILDE,DENMARK. INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. ARGONNE NATL LAB,ARGONNE,IL 60439. RI Mortensen, Kell/A-5066-2009 OI Mortensen, Kell/0000-0002-8998-9390 NR 34 TC 17 Z9 17 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 JUN 20 PY 1991 VL 219 IS 4 BP 747 EP 755 DI 10.1016/0022-2836(91)90669-W PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FU062 UT WOS:A1991FU06200020 PM 2056537 ER PT J AU NICHOLAS, JB HOPFINGER, AJ TROUW, FR ITON, LE AF NICHOLAS, JB HOPFINGER, AJ TROUW, FR ITON, LE TI MOLECULAR MODELING OF ZEOLITE STRUCTURE .2. STRUCTURE AND DYNAMICS OF SILICA SODALITE AND SILICATE FORCE-FIELD SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MECHANICS; ABINITIO; NATROLITE; SORPTION AB An accurate valence force field for zeolites is presented. The force field contains terms for bond stretches, bond angle bends, dihedral angles, and Lennard-Jones and electrostatic nonbonded interactions. Various treatments of the electrostatics and their effects on the modeling of silica sodalite are discussed. Theoretical infrared (IR) spectra, radial distribution functions, and mean-square displacements are compared to experimental data, demonstrating that the force field accurately reproduces the structure and dynamics of silica sodalite with use of energy minimization, normal mode analysis, and molecular dynamics techniques. C1 ARGONNE NATL LAB, DIV INTENSE PULSED NEUTRON SOURCE, ARGONNE, IL 60439 USA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RP UNIV ILLINOIS, DEPT CHEM, CHICAGO, IL 60680 USA. NR 39 TC 121 Z9 122 U1 2 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 19 PY 1991 VL 113 IS 13 BP 4792 EP 4800 DI 10.1021/ja00013a012 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA FR954 UT WOS:A1991FR95400012 ER PT J AU PATTEN, TE NOVAK, BM AF PATTEN, TE NOVAK, BM TI LIVING TITANIUM(IV) CATALYZED COORDINATION POLYMERIZATIONS OF ISOCYANATES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID OPTICALLY-ACTIVE POLYISOCYANATES; MACROMOLECULAR STEREOCHEMISTRY; ANIONIC-POLYMERIZATION; BUTYL ISOCYANATE; INSERTION C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT SCI,BERKELEY,CA 94720. NR 37 TC 99 Z9 100 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 JUN 19 PY 1991 VL 113 IS 13 BP 5065 EP 5066 DI 10.1021/ja00013a055 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA FR954 UT WOS:A1991FR95400055 ER PT J AU PIOTROWIAK, P MILLER, JR AF PIOTROWIAK, P MILLER, JR TI SPECTRA OF THE SOLVATED ELECTRON IN THE PRESENCE OF SODIUM-CATION IN TETRAHYDROFURAN AND IN ITS ALPHA,ALPHA'-METHYLATED DERIVATIVES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note RP PIOTROWIAK, P (reprint author), ARGONNE NATL LAB,DIV CHEM,ELECTRON TRANSFER & ENERGY CONVERS GRP,ARGONNE,IL 60439, USA. NR 5 TC 13 Z9 13 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 19 PY 1991 VL 113 IS 13 BP 5086 EP 5087 DI 10.1021/ja00013a069 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA FR954 UT WOS:A1991FR95400069 ER PT J AU REAGOR, D GARZON, F AF REAGOR, D GARZON, F TI DIELECTRIC AND OPTICAL-PROPERTIES OF SUBSTRATES FOR HIGH-TEMPERATURE SUPERCONDUCTOR FILMS SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS AB The dielectric constants-epsilon of LaAlO3, NdGaO3 and MgO substrates were measured using a dielectric filled resonant cavity. Precise values of epsilon were obtained for NdGaO3 and MgO. An inhomogeneous dielectric constant was observed for LaAlO3. Optical studies indicated that the extensive twinning in this material was the source of the inhomogeneity. RP REAGOR, D (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 6 TC 16 Z9 16 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 JUN 17 PY 1991 VL 58 IS 24 BP 2741 EP 2743 DI 10.1063/1.104772 PG 3 WC Physics, Applied SC Physics GA FR444 UT WOS:A1991FR44400006 ER PT J AU SCOFIELD, JH TRAWICK, M KLIMECKY, P FLEETWOOD, DM AF SCOFIELD, JH TRAWICK, M KLIMECKY, P FLEETWOOD, DM TI CORRELATION BETWEEN PREIRRADIATION CHANNEL MOBILITY AND RADIATION-INDUCED INTERFACE-TRAP CHARGE IN METAL-OXIDE-SEMICONDUCTOR TRANSISTORS SO APPLIED PHYSICS LETTERS LA English DT Article ID 1/F NOISE; DEVICES; DEFECTS; MODEL AB We find a strong correlation between preirradiation channel resistance and radiation-induced interface-trap charge in n-channel metal-oxide-semiconductor (MOS) transistors. While it has long been known that the postirradiation mobility of MOS transistors degrades with exposure to ionizing radiation, we believe this is the first time that differences in the postirradiation interface-trap charge have been linked to differences in preirradiation device parameters. A simple model is presented that relates the observed variations in preirradiation channel resistance to scattering from defects at the Si/SiO2 interface which may be precursors to the radiation-induced interface-trap charge. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP SCOFIELD, JH (reprint author), OBERLIN COLL,DEPT PHYS,OBERLIN,OH 44074, USA. NR 18 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 17 PY 1991 VL 58 IS 24 BP 2782 EP 2784 DI 10.1063/1.104760 PG 3 WC Physics, Applied SC Physics GA FR444 UT WOS:A1991FR44400020 ER PT J AU GAZDZICKI, M HANSEN, O AF GAZDZICKI, M HANSEN, O TI HADRON-PRODUCTION IN NUCLEON NUCLEON COLLISIONS AT 200 GEV/C - A COMPILATION SO NUCLEAR PHYSICS A LA English DT Article ID STRANGE-PARTICLE-PRODUCTION; P-P INTERACTIONS; 300 GEV-C; DISTRIBUTIONS; LAMBDA; GAMMA AB Data on stable hadron production in p + p and p + n interactions at 200 GeV/c are reviewed. Methods to construct missing data in the p + p, p + n, and n + n interactions are derived from charge symmetry and charge, baryon and strangeness conservation, and used to yield nucleon-nucleon interaction results. These may be useful for evaluating nucleus-nucleus collision measurements in terms of enhancements and suppressions. Parameterizations of p(t)2 and rapidity distributions are presented to provide yields in acceptance cuts for comparisons to nucleus-nucleus data. As an example the derived nucleon-nucleon multiplicities are reduced to the acceptance of the NA-35 CERN S + S experiment. C1 STATE UNIV GRONINGEN,KVI,9700 AB GRONINGEN,NETHERLANDS. UNIV FRANKFURT,FACHBEREICH PHYS,W-6000 FRANKFURT 1,GERMANY. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP GAZDZICKI, M (reprint author), UNIV WARSAW,INST EXPTL PHYS,PL-00325 WARSAW,POLAND. NR 27 TC 72 Z9 72 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 JUN 17 PY 1991 VL 528 IS 3-4 BP 754 EP 770 DI 10.1016/0375-9474(91)90261-4 PG 17 WC Physics, Nuclear SC Physics GA FU780 UT WOS:A1991FU78000015 ER PT J AU MORRIS, TR AF MORRIS, TR TI CHEQUERED SURFACES AND COMPLEX MATRICES SO NUCLEAR PHYSICS B LA English DT Article ID ONE DIMENSION; STRINGS; LESS AB We investigate a large-N matrix model involving general complex matrices. It can be reinterpreted as a model of two hermitian matrices with specific couplings, and as a model of positive definite hermitian matrices. Large-N perturbation theory generates dynamical triangulations in which the triangles can be chequered (i.e. coloured so that neighbours are opposite colours). On a sphere there is a simple relation between such triangulations and those generated by the single hermitian matrix model. For the torus (and a quartic potential) we solve the counting problem for the number of triangulations that cannot be chequered. The critical physics of chequered triangulations is the same as that of the hermitian matrix model. We show this explicity by solving non-perturbatively pure two-dimensional "chequered" gravity. The interpretative framework given here applies to a number of other generalizations of the hermitian matrix model. C1 UNIV SOUTHAMPTON,DEPT PHYS,SOUTHAMPTON SO9 5NH,HANTS,ENGLAND. RP MORRIS, TR (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 22 TC 53 Z9 53 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD JUN 17 PY 1991 VL 356 IS 3 BP 703 EP 728 DI 10.1016/0550-3213(91)90383-9 PG 26 WC Physics, Particles & Fields SC Physics GA FP514 UT WOS:A1991FP51400006 ER PT J AU EILAM, G MENDEL, RR MIGNERON, R SONI, A AF EILAM, G MENDEL, RR MIGNERON, R SONI, A TI RADIATIVE-CORRECTIONS TO TOP-QUARK DECAY SO PHYSICAL REVIEW LETTERS LA English DT Article ID RENORMALIZATION; MASSES AB We calculate all radiative corrections to one-loop order for the main decay of the top quark, t --> b + W, in the standard model, retaining exact dependence on all masses. For m(t) = 150 GeV and M(H) = 100 GeV we find a -2.9% ( -6.9%) correction with a very weak dependence on the Higgs-boson mass, in renormalization schemes that use alpha, G(F), and M(Z) (G(F), M(W), and M(Z) as input parameters. Out of the above results, -8.5% is due to QCD. The m(t), and M(H) dependence is given up to 300 and 1000 GeV, respectively. The inadequacy of a leading m(t) calculation is pointed out. C1 UNIV WESTERN ONTARIO,DEPT APPL MATH,LONDON N6A 5B9,ONTARIO,CANADA. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP EILAM, G (reprint author), TECHNION ISRAEL INST TECHNOL,DEPT PHYS,IL-32000 HAIFA,ISRAEL. NR 17 TC 78 Z9 78 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3105 EP 3108 DI 10.1103/PhysRevLett.66.3105 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100005 ER PT J AU CLOSE, FE LI, ZP AF CLOSE, FE LI, ZP TI POLARIZATION OF TENSOR MESONS IN PSI-RADIATIVE DECAYS AND POSSIBLE IMPLICATIONS FOR THE GLUONIC CONTENT OF THE THETA(1720) SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUARK-MODEL AB We present a resolution to the problem of the helicity structure of tensor mesons produced in psi --> gamma-T. The new feature is that the diagrams are separated according to their different topologies, the corresponding helicity structures being analyzed for each diagram. Different topologies appear to dominate the f2(1270,1525) qqbar production and the theta/f2(1720) production, suggesting that the theta-production samples large transverse momentum p(t) in the psi-wave function. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RUTHERFORD APPLETON LAB,DIV THEORY,DIDCOT OX11 0QX,OXON,ENGLAND. RP CLOSE, FE (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 29 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3109 EP 3112 DI 10.1103/PhysRevLett.66.3109 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100006 ER PT J AU MISHRA, SR RABINOWITZ, SA ARROYO, C BACHMANN, KT BLAIR, RE FOUDAS, C KING, BJ LEFMANN, WC LEUNG, WC OLTMAN, E QUINTAS, PZ SCIULLI, FJ SELIGMAN, BG SHAEVITZ, MH MERRITT, FS OREGLIA, MJ SCHUMM, BA BERNSTEIN, RH BORCHERDING, F FISK, HE LAMM, MJ MARSH, W MERRITT, KWB SCHELLMAN, H YOVANOVITCH, DD BODEK, A BUDD, HS DEBARBARO, P SAKUMOTO, WK SANDLER, PH SMITH, WH AF MISHRA, SR RABINOWITZ, SA ARROYO, C BACHMANN, KT BLAIR, RE FOUDAS, C KING, BJ LEFMANN, WC LEUNG, WC OLTMAN, E QUINTAS, PZ SCIULLI, FJ SELIGMAN, BG SHAEVITZ, MH MERRITT, FS OREGLIA, MJ SCHUMM, BA BERNSTEIN, RH BORCHERDING, F FISK, HE LAMM, MJ MARSH, W MERRITT, KWB SCHELLMAN, H YOVANOVITCH, DD BODEK, A BUDD, HS DEBARBARO, P SAKUMOTO, WK SANDLER, PH SMITH, WH TI NEUTRINO TRIDENTS AND W-Z INTERFERENCE SO PHYSICAL REVIEW LETTERS LA English DT Article ID FERMILAB TEVATRON ENERGIES; INTERMEDIATE BOSON; MUON; SCATTERING AB We present a measurement of neutrino tridents, muon pairs induced by neutrino scattering in the Coulomb field of a target nucleus, in the Columbia-Chicago-Fermilab-Rochester neutrino experiment at the Fermilab Tevatron. The observed number of tridents after geometric and kinematic corrections, 37.0 +/- 12.4, supports the standard-model prediction of 45.3 +/-2.3 events. This is the first demonstration of the W-Z destructive interference from neutrino tridents, and rules out, at 99% C.L., the V - A prediction without the interference. C1 UNIV CHICAGO,CHICAGO,IL 60637. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV ROCHESTER,ROCHESTER,NY 14627. UNIV WISCONSIN,MADISON,WI 53706. RP MISHRA, SR (reprint author), COLUMBIA UNIV,NEW YORK,NY 10027, USA. OI Bernstein, Robert/0000-0002-7610-950X NR 27 TC 37 Z9 37 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3117 EP 3120 DI 10.1103/PhysRevLett.66.3117 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100008 ER PT J AU TANG, CY BRYANT, HC HARRIS, PG MOHAGHEGHI, AH REEDER, RA SHARIFIAN, H TOOTOONCHI, H QUICK, CR DONAHUE, JB COHEN, S SMITH, WW AF TANG, CY BRYANT, HC HARRIS, PG MOHAGHEGHI, AH REEDER, RA SHARIFIAN, H TOOTOONCHI, H QUICK, CR DONAHUE, JB COHEN, S SMITH, WW TI THRESHOLD STRUCTURES IN THE MULTIPHOTON DETACHMENT YIELD FROM THE H- ION SO PHYSICAL REVIEW LETTERS LA English DT Article ID IONIZATION AB Multiphoton detachment from H- has been studied using linearly Polarized light for photon energies from 0.15 to 0.39 eV. Characteristic threshold structures were observed. The electron detachment rates are estimated at Peak laser intensities from 2 to 12 GW/cm2 in the laboratory frame. The two-photon detachment data reveal intensity-dependent shifts of the H-electron detachment threshold energy. C1 CALIF STATE UNIV LONG BEACH,LONG BEACH,CA 90840. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CONNECTICUT,STORRS,CT 06268. RP TANG, CY (reprint author), UNIV NEW MEXICO,ALBUQUERQUE,NM 87131, USA. NR 15 TC 54 Z9 54 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3124 EP 3127 DI 10.1103/PhysRevLett.66.3124 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100010 ER PT J AU MANSFIELD, DK JANOS, A OWENS, DK SCHMIDT, GL BELL, MG CAVALLO, A FREDRICKSON, E RAMSEY, AT TAYLOR, G AF MANSFIELD, DK JANOS, A OWENS, DK SCHMIDT, GL BELL, MG CAVALLO, A FREDRICKSON, E RAMSEY, AT TAYLOR, G TI LOCAL-DENSITY INCREMENT FROM AN ABLATED DEUTERIUM PELLET IN THE TFTR TOKAMAK SO PHYSICAL REVIEW LETTERS LA English DT Article ID FUSION TEST REACTOR; SYSTEM; PLASMA AB Details of the process by which ionized pellet ablatant increases the density in a tokamak have been observed for the first time. For mild ablation rates, this process is not simply diffusive. Instead, the ionized ablatant takes the form of a temporally symmetric pulse which propagates over large distances along magnetic-field lines. This pulse has been observed both interferometrically and with an x-ray camera . These observations are not in qualitative agreement with models which predict a steplike densification of the plasma by the pellet. RP MANSFIELD, DK (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 10 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3140 EP 3143 DI 10.1103/PhysRevLett.66.3140 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100014 ER PT J AU SCALETTAR, RT BATROUNI, GG ZIMANYI, GT AF SCALETTAR, RT BATROUNI, GG ZIMANYI, GT TI LOCALIZATION IN INTERACTING, DISORDERED, BOSE SYSTEMS SO PHYSICAL REVIEW LETTERS LA English DT Article ID INSULATOR-TRANSITION; SCALING THEORY; HUBBARD CHAIN; FERMI-LIQUID; SUPERCONDUCTIVITY; MODEL AB We use quantum Monte Carlo techniques to study a one-dimensional, disordered, interacting, Bose Hamiltonian. The effect of disorder on the Mott-insulator Portion of the phase diagram is determined. We observe the destruction of superfluidity by disorder at incommensurate densities, for the first time demonstrating the emergence of a "Bose-glass" phase. In addition to these strong-coupling phases, we observe an unanticipated reentrance into an Anderson-type localized regime for weak couplings. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP SCALETTAR, RT (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. RI Batrouni, George/A-9318-2009 NR 20 TC 227 Z9 227 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3144 EP 3147 DI 10.1103/PhysRevLett.66.3144 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100015 ER PT J AU LOONG, CK HINKS, DG VASHISHTA, P JIN, W KALIA, RK DEGANI, MH PRICE, DL JORGENSEN, JD DABROWSKI, B MITCHELL, AW RICHARDS, DR ZHENG, Y AF LOONG, CK HINKS, DG VASHISHTA, P JIN, W KALIA, RK DEGANI, MH PRICE, DL JORGENSEN, JD DABROWSKI, B MITCHELL, AW RICHARDS, DR ZHENG, Y TI OXYGEN ISOTOPE EFFECT IN SUPERCONDUCTING BA1-XKXBIO3 FROM PHONON DENSITY OF STATES SO PHYSICAL REVIEW LETTERS LA English DT Article ID BA0.6K0.4BIO3; TRANSITION; SYSTEM AB The variation of the phonon spectrum of Ba0.6K0.4BiO3 Upon oxygen isotope substitution is determined by inelastic neutron scattering (INS). By combining the INS results with molecular-dynamics computer simulation, a value of 0.42 +/- 0.05 is obtained for the reference isotope-effect exponent. This is close to the isotope-effect exponent determined from the variation of T(c) upon oxygen substitution, indicating that Ba0.6K0.4BiO3 is a weak-coupling superconductor with large matrix elements coupling the electrons to high-energy phonons involving oxygen vibrations. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. LOUISIANA STATE UNIV,CONCURRENT COMP LAB MAT SIMULAT,BATON ROUGE,LA 70803. LOUISIANA STATE UNIV,DEPT PHYS,BATON ROUGE,LA 70803. RP LOONG, CK (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013 NR 22 TC 39 Z9 39 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3217 EP 3220 DI 10.1103/PhysRevLett.66.3217 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100034 ER PT J AU KWAN, TJT MOSTROM, MA GODFREY, BB AF KWAN, TJT MOSTROM, MA GODFREY, BB TI ELECTRON-BEAM-BREAKUP TRANSIT-TIME OSCILLATOR SO PHYSICAL REVIEW LETTERS LA English DT Article AB The electron-beam-breakup transit-time oscillator has been investigated via theoretical analysis and computer simulation as a high-power microwave generator. Coupling the beam-breakup instability with the transit-time effect of the electron beam in the cavity, rapid energy exchange between the electrons and cavity modes can occur. Furthermore, the transit-time resonance naturally leads to narrow-band output. Driven by a high-current electron beam, the beam-breakup transit-time oscillator can be a compact source for high-power ( > 1 GW) operation. Good agreements have been obtained between linear theory and simulation. C1 MISSION RES CORP,ALBUQUERQUE,NM 87106. RP KWAN, TJT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545, USA. RI Godfrey, Brendan/D-8204-2011 OI Godfrey, Brendan/0000-0003-2311-7060 NR 7 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 17 PY 1991 VL 66 IS 24 BP 3221 EP 3224 DI 10.1103/PhysRevLett.66.3221 PG 4 WC Physics, Multidisciplinary SC Physics GA FR051 UT WOS:A1991FR05100035 ER PT J AU LIGHTFOOT, P PEI, SY JORGENSEN, JD YAMADA, Y MATSUMOTO, T IZUMI, F KODAMA, Y AF LIGHTFOOT, P PEI, SY JORGENSEN, JD YAMADA, Y MATSUMOTO, T IZUMI, F KODAMA, Y TI REDETERMINATION OF THE STRUCTURE OF THE 80-K SUPERCONDUCTOR YBA2CU4O8 BY TIME-OF-FLIGHT NEUTRON POWDER DIFFRACTION SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID TC AB M(r) = 745.77, orthorhombic, Ammm, a = 3.8402 (1), b = 3.8708 (1), c = 27.2309 (3) angstrom, V = 404.8 angstrom 3, D(x) = 6.119 g cm-3, Z = 2, T = 295 K, 912 reflections included, R(wp) = 5.62%, R(exp) = 3.34%. Rietveld analysis of high-resolution time-of-flight powder neutron diffraction data has been used to redetermine the structure of the 80 K superconductor YBa2Cu4O8 (the '124 phase'). The essential features of the structure previously reported have been confirmed. This study improves upon the precision of the previously reported structural parameters, obtained by powder neutron diffraction. The compound is stoichiometric, with no occupancy of the O(5) inter-chain site. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NATL RES INST MET,MEGURO KU,TOKYO 153,JAPAN. NATL INST RES INORGAN MAT,TSUKUBA,IBARAKI 3095,JAPAN. GOVT IND RES INST,KITA KU,NAGOYA,AICHI 462,JAPAN. RP LIGHTFOOT, P (reprint author), ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439, USA. NR 7 TC 28 Z9 28 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 JUN 15 PY 1991 VL 47 BP 1143 EP 1145 DI 10.1107/S0108270190011271 PN 6 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FU704 UT WOS:A1991FU70400005 ER PT J AU GEISER, U TYTKO, SF ALLEN, TJ WANG, HH KINI, AM WILLIAMS, JM AF GEISER, U TYTKO, SF ALLEN, TJ WANG, HH KINI, AM WILLIAMS, JM TI STRUCTURE OF BIS(2,3-DIMERCAPTO-6,7-DIHYDRO-5H-1,4-DITHIEPIN)NICKEL(IV) AT 295-K AND 109-K SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID CRYSTAL-STRUCTURE; MOLECULAR SUPERCONDUCTOR; BIS(5,6-DIHYDRO-1,4-DITHIIN-2,3-DITHIOLATO)NICKELATE(III); SALTS AB C10H12NiS8, M(r) = 447.4, orthorhombic, Iba2, T = 295 (109) K, a = 13.058 (5) [13.027 (3)], b = 16.153 (9) [16.042 (6)], c = 7.585 (4) [7.486 (2)] angstrom, V = 1600 (1) [1564.5 (8)] angstrom 3, Z = 4, D(x) = 1.857 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 2.20 mm-1, F(000) = 912, final R = 0.036 (0.029) for 940 (1355) independent observed reflections with F-omicron > 2-sigma-(F(omicron)). The molecules, which are analogues of the organic donor molecule 3,4;3',4'-bis(propylenedithio)-2,2'5,5'-tetrathiafulvalene (BPDT-TTF), contain a markedly nonplanar central NiS4 entity, as compared with the derivative containing six-membered end-group rings, Ni(C4H4S4)2. The structural changes between the two temperatures are very small. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP GEISER, U (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Kini, Aravinda/F-4467-2012 NR 17 TC 14 Z9 14 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 JUN 15 PY 1991 VL 47 BP 1164 EP 1167 DI 10.1107/S0108270190013117 PN 6 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FU704 UT WOS:A1991FU70400013 ER PT J AU CHANTRANUPONG, L HIRSCH, G BUENKER, RJ KIMURA, M DILLON, MA AF CHANTRANUPONG, L HIRSCH, G BUENKER, RJ KIMURA, M DILLON, MA TI THEORETICAL-STUDY OF THE ELECTRONIC-SPECTRUM OF AMMONIA - GENERALIZED OSCILLATOR STRENGTH CALCULATIONS FOR THE A-X TRANSITION SO CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION; ENERGY EXTRAPOLATION; INVERSION BARRIER; CI CALCULATIONS; EXCITATION; MOLECULE; ABINITIO; STATES; H2O AB A series of ab initio CI calculations is reported for the electronic spectrum of ammonia. The generalized oscillator strength for the A-X n --> 3s Rydberg transition is computed as a function of the square of the momentum transfer vector in electron impact studies and the results are found to be in good agreement with the corresponding measured data. Vertical and adiabatic transition energies are also reported for a series of low-energy Rydberg transitions involving 3p, 3d, 4s and 4p upper orbitals and these results are also found to compare well with the corresponding experimental findings. Optical f values for the latter transitions have also been computed. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP CHANTRANUPONG, L (reprint author), BERG UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH 9,GAUSSTR 20,W-5600 WUPPERTAL 1,GERMANY. NR 30 TC 14 Z9 14 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 15 PY 1991 VL 154 IS 1 BP 13 EP 21 DI 10.1016/0301-0104(91)89038-C PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FT030 UT WOS:A1991FT03000002 ER PT J AU RAO, SI HOUSKA, CR GRABOWSKI, K ICE, G SPARKS, CJ AF RAO, SI HOUSKA, CR GRABOWSKI, K ICE, G SPARKS, CJ TI X-RAY DIFFUSE-SCATTERING FROM A NITROGEN-IMPLANTED NIOBIUM FILM SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SYNCHROTRON RADIATION; POWDER DIFFRACTION; DISLOCATION LOOPS; CRYSTALS AB A 2500-angstrom niobium single-crystal film was deposited onto a sapphire substrate and subsequently implanted with nitrogen to an average concentration of 0.5 at. %. Synchrotron radiation was used to measure the difference between the implanted and an unimplanted film to isolate the diffuse scattering from the implanted film near two Bragg reflections. This diffuse intensity arises mainly from elastic displacement fields about radiation-damage-related loops located on (211) planes. A small contribution of the scattering is calculated from the displacements about single interstitial nitrogen in octahedral sites. The Burgers vector of the loops is along the [111BAR] direction and makes an angle of 62-degrees with the loop plane giving a dominant shear component. Vacancy loops have a radius approximately 5 angstrom while interstitials are somewhat larger ranging from 10 to 15 angstrom. The number of vacancies and interstitials are nearly the same. C1 USN,RES LAB,WASHINGTON,DC 20375. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP RAO, SI (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT MAT ENGN,BLACKSBURG,VA 24061, USA. OI Grabowski, Kenneth/0000-0003-0816-001X NR 17 TC 7 Z9 7 U1 3 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1991 VL 69 IS 12 BP 8104 EP 8110 DI 10.1063/1.347460 PG 7 WC Physics, Applied SC Physics GA FU812 UT WOS:A1991FU81200021 ER PT J AU MARTENS, JS ZIPPERIAN, TE GINLEY, DS HIETALA, VM TIGGES, CP PLUT, TA AF MARTENS, JS ZIPPERIAN, TE GINLEY, DS HIETALA, VM TIGGES, CP PLUT, TA TI THE EFFECTS OF PROCESSING SEQUENCES ON THE MICROWAVE SURFACE-RESISTANCE OF TLCABACUO SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TRANSMISSION AB The effects of several microelectronic processing sequences on the high-frequency surface resistance of the high-temperature superconducting thin films in the TlCaBaCuO system have been examined. These processes include an acid etch, Br/alcohol etches, positive and negative photoresist sequences, and exposure to de-ionized water. The surface resistance decreases during the Br etch, remains constant during the negative photoresist process, and increases moderately during the positive photoresist sequence and on exposure to water. The surface resistance increases dramatically on exposure to the acid solution as might be expected from other work. The effects of extended exposures to de-ionized water and to Br etches on surface resistance are also presented. RP MARTENS, JS (reprint author), SANDIA NATL LABS,DEPT 1140,ALBUQUERQUE,NM 87185, USA. NR 9 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 JUN 15 PY 1991 VL 69 IS 12 BP 8268 EP 8271 DI 10.1063/1.347434 PG 4 WC Physics, Applied SC Physics GA FU812 UT WOS:A1991FU81200048 ER PT J AU SHERWIN, ME DRUMMOND, TJ AF SHERWIN, ME DRUMMOND, TJ TI PREDICTED ELASTIC-CONSTANTS AND CRITICAL LAYER THICKNESSES FOR CUBIC PHASE ALN, GAN, AND INN ON BETA-SIC SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID MOLECULAR-BEAM EPITAXY; ELECTRONIC-PROPERTIES; GALLIUM NITRIDE; PRESSURE; GROWTH AB Elastic constants for zinc-blende AlN, GaN, and InN have been estimated from the elastic constants of the wurtzite phase. This has been accomplished by recognizing that the crystal structures of the wurtzite and zinc-blende phases are related by a simple rotation. This rotation was then applied to the elastic constants and a least-squares fit is used to match the results. Using the zinc-blende elastic constants the critical thickness of the nitrides on beta-SiC substrates was calculated. The critical thickness of a single overlayer of AlN was calculated to be 14.1 nm, and for GaN the critical thickness was found to be 0.7 nm. In the elastic continuum model used there was no solution for the critical thickness of InN. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP SHERWIN, ME (reprint author), UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. NR 12 TC 148 Z9 149 U1 2 U2 27 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 JUN 15 PY 1991 VL 69 IS 12 BP 8423 EP 8425 DI 10.1063/1.347412 PG 3 WC Physics, Applied SC Physics GA FU812 UT WOS:A1991FU81200078 ER PT J AU THOMAS, J VANPATTEN, SM HOWARD, P DAY, KH MITCHELL, RD SOSNICK, T TREWHELLA, J WALSH, DA MAURER, RA AF THOMAS, J VANPATTEN, SM HOWARD, P DAY, KH MITCHELL, RD SOSNICK, T TREWHELLA, J WALSH, DA MAURER, RA TI EXPRESSION IN ESCHERICHIA-COLI AND CHARACTERIZATION OF THE HEAT-STABLE INHIBITOR OF THE CAMP-DEPENDENT PROTEIN-KINASE SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID DIRECT CYTOCHEMICAL-LOCALIZATION; RABBIT SKELETAL-MUSCLE; H-35 HEPATOMA-CELLS; CATALYTIC SUBUNIT; REGULATORY SUBUNIT; SITE-A; PURIFICATION; BINDING; DELETION AB Pure heat-stable inhibitor of the cAMP-dependent protein kinase (PKI) has been isolated in high yield by using a bacterial expression vector constructed to synthesize the complete sequence of the rabbit muscle protein kinase inhibitor, plus an amino-terminal initiator methionine and glycine. Bacterially expressed PKI has an inhibitory activity identical to that of the protein isolated from rabbit skeletal muscle and, by gel filtration and gel electrophoresis, has the same physicochemical characteristics as the native physiological form of PKI. Fourier transformed infrared spectroscopy and CD establish that PKI has unusually large amounts of random coil and turn structures, with significantly smaller amounts of alpha-helix and beta-structures. C1 UNIV IOWA,DEPT PHYSIOL & BIOPHYS,IOWA CITY,IA 52242. UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616. UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. OI Trewhella, Jill/0000-0002-8555-6766 FU NHLBI NIH HHS [HL14388]; NIADDK NIH HHS [AM21019, AM25295] NR 38 TC 45 Z9 46 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUN 15 PY 1991 VL 266 IS 17 BP 10906 EP 10911 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FQ774 UT WOS:A1991FQ77400034 PM 2040607 ER PT J AU NATANSON, GA GARRETT, BC TRUONG, TN JOSEPH, T TRUHLAR, DG AF NATANSON, GA GARRETT, BC TRUONG, TN JOSEPH, T TRUHLAR, DG TI THE DEFINITION OF REACTION COORDINATES FOR REACTION-PATH DYNAMICS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-STATE-THEORY; SEMICLASSICAL TUNNELING CALCULATIONS; INTRINSIC REACTION COORDINATE; POTENTIAL-ENERGY SURFACE; CHEMICAL-REACTION RATES; ATOM TRANSFER-REACTIONS; RATE CONSTANTS; UNIMOLECULAR REACTION; POLYATOMIC-MOLECULES; ABINITIO CALCULATION AB We present equations for generalized-normal-mode vibrational frequencies in reaction-path calculations based on various sets of coordinates for describing the internal motions of the system in the vicinity of a reaction path. We consider two special cases in detail as examples, in particular three-dimensional atom-diatom collisions with collinear steepest descent paths and reactions of the form CX3 + YZ --> CX3Y + Z with reaction paths having C3-upsilon symmetry. We then present numerical comparisons of the differences in harmonic reaction-path frequencies for various coordinate choices for three such systems, namely, H + H-2 --> H-2 + H, O + H-2 --> OH + H, and CH3 + H-2 --> CH4 + H. We test the importance of the differences in the harmonic frequencies for dynamics calculations by using them to compute thermal rate constants using variational transition state theory with semiclassical ground-state tunneling corrections. We present a new coordinate system for the reaction CH3 + H-2 that should allow for more accurate calculations than the Cartesian system used for previous reaction-path calculations on this and other polyatomic systems. C1 PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. RP COMP SCI CORP, SEABROOK, MD 20706 USA. RI Garrett, Bruce/F-8516-2011; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 101 TC 108 Z9 108 U1 0 U2 16 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1991 VL 94 IS 12 BP 7875 EP 7892 DI 10.1063/1.460123 PN 1 PG 18 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FQ584 UT WOS:A1991FQ58400032 ER PT J AU BALKO, BA ZHANG, J LEE, YT AF BALKO, BA ZHANG, J LEE, YT TI 193-NM PHOTODISSOCIATION OF ACETYLENE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BOND-DISSOCIATION ENERGY; LASER KINETIC SPECTROSCOPY; POTENTIAL SURFACES; C2H; EMISSION; TRANSITION; ETHYLENE; SPECTRUM; PHOTOLYSIS; STRENGTHS AB The product translational energy distribution P(E(T)) for acetylene photodissociation at 193 nm was obtained from the time-of-flight spectrum of the H atom fragments. The P(E(T)) shows resolved structure from the vibrational and electronic excitation of the C2H fragment; comparison of the translational energy release for given excited states of C2H with the known energy levels of these states gives D0(HCC-H) = 131.4 +/- 0.5 kcal/mol. This value is in agreement with that determined previously in this group from analogous studies of the C2H fragment and with the latest experimental and theoretical work. The high resolution of the experiment also reveals the nature of C2H internal excitation. A significant fraction of the H atoms detected at moderate laser power were from the secondary dissociation of C2H. The P(E(T)) derived for this channel indicates that most of the C2 is produced in excited electronic states. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP BALKO, BA (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Lee, Yuan-Tseh/F-7914-2012 NR 48 TC 79 Z9 79 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1991 VL 94 IS 12 BP 7958 EP 7966 DI 10.1063/1.460130 PN 1 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FQ584 UT WOS:A1991FQ58400039 ER PT J AU XANTHEAS, SS ATCHITY, GJ ELBERT, ST RUEDENBERG, K AF XANTHEAS, SS ATCHITY, GJ ELBERT, ST RUEDENBERG, K TI POTENTIAL-ENERGY SURFACES OF OZONE .1. SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPACE SCF METHOD; EXCITED-STATES; CYCLIC OZONE; THEORETICAL EVIDENCE; NONCROSSING RULE; GROUND-STATE; MOLECULE; FORMS; DISSOCIATION; SEPARATION AB The cross section through the ground-state potential energy surface of ozone which contains the open minimum, the ring minimum, and the ring-opening reaction path, including the ring-opening transition state, is determined through full-valence-space multiconfiguration self-consistent-field calculations. It is shown that, at a point on the ridge separating the open-structure basin from the ring-structure basin in C2-upsilon symmetry, very close to the transition state, the ground-state surface connects with the lowest excited state surface of the same symmetry (1A1). This point is part of an intersection seam between these two 1A' surfaces in C(s) symmetry. It is furthermore found that the upper state has its equilibrium structure very close to the transition state of the lower state. The quantitative data of all critical points are calculated. In addition, a ground-state potential energy surface cross section describing the detachment of an oxygen atom is determined. For several other states, C2-upsilon constrained and bond-length-optimized energy curves E(phi) are also reported. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RI Xantheas, Sotiris/L-1239-2015; Elbert, Stephen/F-9019-2016; OI Elbert, Stephen/0000-0003-2258-8901; Xantheas, Sotiris/0000-0002-6303-1037 NR 52 TC 124 Z9 124 U1 0 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1991 VL 94 IS 12 BP 8054 EP 8069 DI 10.1063/1.460140 PN 1 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FQ584 UT WOS:A1991FQ58400050 ER PT J AU KIMURA, M KRAJCARBRONIC, I INOKUTI, M AF KIMURA, M KRAJCARBRONIC, I INOKUTI, M TI ELECTRON DEGRADATION AND YIELDS OF INITIAL PRODUCTS .8. SUBEXCITATION ELECTRONS IN H-2 AND D2 GASES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-HYDROGEN; SLOW-ELECTRONS AB The moderation of subexcitation electrons in H-2 and D2 is investigated by using the Spencer-Fano (SF) equation and the continuous-slowing-down approximation (CSDA). Cross-section data are adopted from the compilation by Buckman and Phelps [J. Chem. Phys. 82, 5001 (1985)]. Throughout, we focus on isotope effects, i.e., differences between H-2 and D2, and consider electrons at energies appreciably higher than thermal energy. In summary, because vibrational and rotational excitation channels have lower thresholds in D2, subexcitation-electron behavior in D2 at energies below 0.6 eV shows different characteristics from that in H-2. The moderation rate in H-2 is larger than that in D2 by a factor of about 1.7. This difference is close to but not exactly the factor of 2 expected from an elementary estimate. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RUDJER BOSKOVIC INST,YU-41001 ZAGREB,YUGOSLAVIA. NR 21 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1991 VL 94 IS 12 BP 8244 EP 8251 DI 10.1063/1.460108 PN 2 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FQ585 UT WOS:A1991FQ58500009 ER PT J AU WINTER, BJ PARKS, EK RILEY, SJ AF WINTER, BJ PARKS, EK RILEY, SJ TI COPPER CLUSTERS - THE INTERPLAY BETWEEN ELECTRONIC AND GEOMETRICAL STRUCTURE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID MASS DISTRIBUTIONS; SHELL STRUCTURE; ICOSAHEDRAL STRUCTURE; CHEMISTRY; SILVER; GOLD RP WINTER, BJ (reprint author), ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. RI Winter, Bernd/D-4657-2011 NR 16 TC 99 Z9 100 U1 0 U2 10 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1991 VL 94 IS 12 BP 8618 EP 8621 DI 10.1063/1.460046 PN 2 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FQ585 UT WOS:A1991FQ58500052 ER PT J AU CHEN, CW AF CHEN, CW TI FABRICATION AND CHARACTERIZATION OF THIN-FILMS WITH PERPENDICULAR MAGNETIC-ANISOTROPY FOR HIGH-DENSITY MAGNETIC RECORDING .2. A REVIEW SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID CO-CR FILMS; DOUBLE-LAYER MEDIA; SPUTTERED COCR; REVERSAL MECHANISM; FERROMAGNETIC-RESONANCE; ELECTRON HOLOGRAPHY; MULTILAYER FILMS; COERCIVE FORCE; MICROSTRUCTURE; HEAD AB Perpendicular magnetic anisotropy (PMA) was first observed in thin films of cobalt-chromium alloys in 1974, and perpendicular magnetic recording was proposed in 1977. After less than ten years, a new technology for high-density magnetic recording is firmly established. This breakthrough of the science and technology of magnetic recording has been made possible mainly through the ingenuity and concerted efforts of Iwasaki and other researchers. The preparation, characterization, and application of the Co-Cr films featuring PMA have been extensively studied. This paper reviews the large number of reports on PMA films with emphasis in three areas: (1) processing of PMA films; (2) correlation of magnetic properties and microstructures of PMA films; and (3) state-of-the-art techniques for fabricating PMA films. RP CHEN, CW (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DEPT CHEM & MAT SCI, BERKELEY, CA 94720 USA. NR 153 TC 6 Z9 6 U1 1 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2461 EI 1573-4803 J9 J MATER SCI JI J. Mater. Sci. PD JUN 15 PY 1991 VL 26 IS 12 BP 3125 EP 3153 DI 10.1007/BF01124655 PG 29 WC Materials Science, Multidisciplinary SC Materials Science GA FT510 UT WOS:A1991FT51000002 ER PT J AU BADRIEH, Y BLUM, J AMER, I VOLLHARDT, KPC AF BADRIEH, Y BLUM, J AMER, I VOLLHARDT, KPC TI CYCLO-OLIGOMERIZATION AND REARRANGEMENT OF SOME PHENYLATED DIYNES BY THE RHCL3-ALIQUAT-336 AND BY THE H2PTCL6-ALIQUAT-336 CATALYSTS UNDER PHASE-TRANSFER CONDITIONS SO JOURNAL OF MOLECULAR CATALYSIS LA English DT Article ID SYSTEM; ALKYNES AB The phenylated diynes 3,3'-oxybis(1-phenyl-1-propyne) (3), its thio-analog 4, 1,2-bis (phenylethynyl)benzene (5) and 1,8-bis(phenylethynyl)naphthalene (6) were reacted, under phase transfer conditions, in the presence of the ion pairs generated from Aliquat(R) 336 and either aqueous RhCl3 or H2PtCl6. The nature of the products proved to depend on the catalyst employed. The rhodium catalyst promotes the conversion of 3 into a mixture of trimer 8 and dimer 7a, as well as the hydrolysis of the latter compound to give 1,3-dihydro-4,6,7-triphenyl-5-isobenzofuranmethanol (9). The sulfur compound 4 yields only hydrolysis-resistant 1,3-dihydro-5-[2-propynyl(thiomethyl)]benzo[c]thiophen (7b), and 6 forms mainly dimer 17 accompanied by small amounts of 7-phenyl- and 7-chloro-12-phenylbenzo[k]fluoranthene (16a and 16b, respectively). The platinum catalyst promotes particularly intramolecular cycloaddition reactions of the diynes. Compound 3 is transformed almost entirely to 1,3-dihydro-9-phenylindeno[1,2-c]pyran (12), 5 is isomerized to give solely 5-phenylindeno[1,2-a]indene (15), and 6 yields 16a and 12-phenylindeno [2,1-a]phenalene (18), as the minor and major products. C1 HEBREW UNIV JERUSALEM,DEPT ORGAN CHEM,IL-91904 JERUSALEM,ISRAEL. BEN GURION UNIV NEGEV,DEPT CHEM,IL-84105 BEER SHEVA,ISRAEL. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. NR 17 TC 29 Z9 29 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-5102 J9 J MOL CATAL PD JUN 15 PY 1991 VL 66 IS 3 BP 295 EP 312 DI 10.1016/0304-5102(91)80022-U PG 18 WC Chemistry, Physical SC Chemistry GA FW904 UT WOS:A1991FW90400005 ER PT J AU BLUM, J BITAN, G MARX, S VOLLHARDT, KPC AF BLUM, J BITAN, G MARX, S VOLLHARDT, KPC TI TRANSFER HYDROGENATION OF DIARYLACETYLENES BY POLYMETHYLHYDROSILOXANE IN THE PRESENCE OF THE RHCL3-ALIQUAT-336 CATALYST SO JOURNAL OF MOLECULAR CATALYSIS LA English DT Article ID HAMMETT EQUATION; SYSTEM AB The ion pair [(C8H17)3NCH3]+ [RhCl4(H2O)2]-, formed from aqueous rhodium chloride and Aliquat(R) 336, has been shown to catalyze transfer hydrogenation of diarylacetylenes by polymethylhydrosiloxane (PMHS) to give Z- and E-stilbenes as the major and the minor products, respectively. The reduction of diphenylacetylene was found to follow first-order kinetics in the substrate between 0.025 and 2.0 M. Both the steric and the electronic nature of the substrate proved to affect the rate. The electronic effect could be expressed in terms of two separate Hammett plots, one with rho = 0.64 for electron-withdrawing substituents and one with rho = -1.10 for the alkynes with electron-releasing groups. Application of either a deuterium-labelled organic phase or D2O led to mono- and dideuterated products. The observed activation energy E(a) = 11.47 kcal mol-1 suggests that the process is both chemically and diffusion controlled. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP BLUM, J (reprint author), HEBREW UNIV JERUSALEM,DEPT ORGAN CHEM,IL-91904 JERUSALEM,ISRAEL. NR 16 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-5102 J9 J MOL CATAL PD JUN 15 PY 1991 VL 66 IS 3 BP 313 EP 319 DI 10.1016/0304-5102(91)80023-V PG 7 WC Chemistry, Physical SC Chemistry GA FW904 UT WOS:A1991FW90400006 ER PT J AU WALTERS, RT NOBILE, A MOSLEY, WC AF WALTERS, RT NOBILE, A MOSLEY, WC TI HELIUM DYNAMICS IN METAL TRITIDES .2. THE SIGNIFICANCE OF MICROSTRUCTURE IN THE OBSERVED HELIUM BEHAVIOR FOR LA-NI-AL TRITIDES SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article ID HYDRIDES; HE-3 AB Helium from tritium decay causes the desorption isotherm plateau pressure for LaNi4.25Al0.75 tritide to be lowered. From the shape of the He-3 altered isotherm, it appears that the material becomes disordered and possibly disproportioned. The microstructure of the parent LaNi4.25Al0.75 tritide material is believed to influence the behavior of He-3 from tritium decay. RP WALTERS, RT (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER LAB,AIKEN,SC 29808, USA. NR 22 TC 19 Z9 23 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD JUN 15 PY 1991 VL 170 IS 1 BP 63 EP 74 DI 10.1016/0022-5088(91)90051-5 PG 12 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FT656 UT WOS:A1991FT65600008 ER PT J AU SHENOY, GK AF SHENOY, GK TI STATUS OF THE ADVANCED PHOTON SOURCE PROJECT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT INTERNATIONAL SYMP ON X-RAY SYNCHROTRON RADIATION AND ADVANCED SCIENCE AND TECHNOLOGY CY FEB 15-16, 1990 CL KOBE, JAPAN SP INST PHYS & CHEM RES, JAPAN ATOM ENERGY RES INST ID GALLIUM AB An introduction to the Advanced Photon Source project is provided through a brief description of the project elements, conventional facilities and technical goals. The current status of the project is provided in the selected areas of R&D, design, construction, funding, staffing, management and user activities. Emphasis is placed on the R&D activities and on the production of prototypes of various technical components to realize a facility with very high reliability and stability. Attention is also paid to aspects related to control and integration of the entire project in relation to its cost and schedule. The project was initiated in 1983; construction will begin during 1990 with planned completion in 1995. RP SHENOY, GK (reprint author), ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439, USA. NR 8 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 15 PY 1991 VL 303 IS 3 BP 413 EP 420 DI 10.1016/0168-9002(91)90279-Y PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FU288 UT WOS:A1991FU28800004 ER PT J AU BENICEWICZ, PK ROBERTS, JP TAYLOR, AJ AF BENICEWICZ, PK ROBERTS, JP TAYLOR, AJ TI GENERATION OF 39-FS PULSES AT 815-NM WITH A SYNCHRONOUSLY PUMPED MODE-LOCKED DYE-LASER SO OPTICS LETTERS LA English DT Article ID 800-NM AB We describe a synchronously pumped mode-locked dye laser that uses a novel combination of saturable absorber dyes (HITC-I and DTP) to yield satellite-free, 39-fs pulses at 815 nm. RP BENICEWICZ, PK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LASER & OPT SCI GRP,CLS-5,MS E543,LOS ALAMOS,NM 87544, USA. NR 8 TC 5 Z9 5 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 1991 VL 16 IS 12 BP 925 EP 927 DI 10.1364/OL.16.000925 PG 3 WC Optics SC Optics GA FQ939 UT WOS:A1991FQ93900015 PM 19776831 ER PT J AU CEDER, G ASTA, M DEFONTAINE, D AF CEDER, G ASTA, M DEFONTAINE, D TI COMPUTATION OF THE OI-OII-OIII PHASE-DIAGRAM AND LOCAL OXYGEN CONFIGURATIONS FOR YBA2CU3OZ WITH Z BETWEEN 6.5 AND 7 SO PHYSICA C LA English DT Article ID DIMENSIONAL ANNNI MODEL; DEFICIENT YBA2CU3O7-DELTA; COMPETING INTERACTIONS; ISING-MODEL; TEMPERATURE; BEHAVIOR; ORDER; SUPERCONDUCTORS; SUPERSTRUCTURES; TRANSITION AB We have computed the low-temperature portion of a phase diagram for the YBa2Cu3O(z) compound between the stoichiometries z = 6.5 and z = 7. Apart from the OI and OII phases the diagram contains a cell tripled superstructure (OIII). It is shown that when the assumption is made that one sublattice in the basal plane is fully depleted, a three-dimensional CVM model has to be used in order to obtain a correct phase diagram. In an attempt to clarify the correlation between oxygen ordering and T(c) we have computed the local oxygen configuration around the Cu(I) atoms as a function of temperature and composition. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP CEDER, G (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. NR 26 TC 86 Z9 86 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN 15 PY 1991 VL 177 IS 1-3 BP 106 EP 114 DI 10.1016/0921-4534(91)90305-I PG 9 WC Physics, Applied SC Physics GA FV360 UT WOS:A1991FV36000018 ER PT J AU SCHARF, R BISHOP, AR AF SCHARF, R BISHOP, AR TI PROPERTIES OF THE NONLINEAR SCHRODINGER-EQUATION ON A LATTICE SO PHYSICAL REVIEW A LA English DT Article ID NONUNIFORM MEDIA; SOLITONS AB We add an on-site potential to the integrable lattice nonlinear Schrodinger equation and show how a number of interesting and novel features can be understood with the help of a simple soliton collective variable approximation. Results include: trapping of a soliton in a linear potential and on a maximum of a smooth potential; trapping of a soliton on a repulsive impurity and breaking into two solitons beyond a critical impurity strength; and a crossover from a soliton state to a local impurity mode upon increasing the strength of an attractive potential. In addition, we prove and illustrate the complete integrability of the system for a linear on-site potential. Results are compared with those for a nonintegrable discretization of the cubic Schrodinger equation. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP SCHARF, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 22 TC 137 Z9 138 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 JUN 15 PY 1991 VL 43 IS 12 BP 6535 EP 6544 DI 10.1103/PhysRevA.43.6535 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FU846 UT WOS:A1991FU84600008 ER PT J AU CHEN, S DOOLEN, GD EGGERT, K GRUNAU, D LOH, EY AF CHEN, S DOOLEN, GD EGGERT, K GRUNAU, D LOH, EY TI LOCAL LATTICE-GAS MODEL FOR IMMISCIBLE FLUIDS SO PHYSICAL REVIEW A LA English DT Note ID AUTOMATA AB We present a lattice-gas model for two-dimensional immiscible fluid flows with surface tension that uses strictly local collision rules. Instead of using a local total color flux as Somers and Rem [Physica D 47, 39 (1991)], we use local colored holes to be the memory of particles of the same color. Interactions between walls and fluids are included that produce arbitrary contact angles. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,LOS ALAMOS,NM 87545. COLORADO STATE UNIV,FT COLLINS,CO 80523. THINKING MACHINES CORP,CAMBRIDGE,MA 02142. RP CHEN, S (reprint author), UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716, USA. RI Chen, Shiyi/A-3234-2010 NR 13 TC 14 Z9 15 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 JUN 15 PY 1991 VL 43 IS 12 BP 7053 EP 7056 DI 10.1103/PhysRevA.43.7053 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FU846 UT WOS:A1991FU84600064 ER PT J AU LUO, LS CHEN, HD CHEN, SY DOOLEN, GD LEE, YC AF LUO, LS CHEN, HD CHEN, SY DOOLEN, GD LEE, YC TI GENERALIZED HYDRODYNAMIC TRANSPORT IN LATTICE-GAS AUTOMATA SO PHYSICAL REVIEW A LA English DT Note ID EQUATION; FLUIDS AB The generalized hydrodynamics of two-dimensional lattice-gas automata is solved analytically in the linearized Boltzmann approximation. The dependence of the transport coefficients (kinematic viscosity, bulk viscosity, and sound speed) upon wave number k is obtained analytically. Anisotropy of these coefficients due to the lattice symmetry is studied for the entire range of wave number, k. Boundary effects due to a finite mean free path (Knudsen layer) are analyzed, and accurate comparisons are made with lattice-gas simulations. C1 GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332. DARTMOUTH COLL,DEPT PHYS,HANOVER,NH 03755. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP LUO, LS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. RI Chen, Shiyi/A-3234-2010; Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 15 TC 26 Z9 27 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 JUN 15 PY 1991 VL 43 IS 12 BP 7097 EP 7100 DI 10.1103/PhysRevA.43.7097 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA FU846 UT WOS:A1991FU84600078 ER PT J AU GUMBSCH, P DAW, MS FOILES, SM FISCHMEISTER, HF AF GUMBSCH, P DAW, MS FOILES, SM FISCHMEISTER, HF TI ACCOMMODATION OF THE LATTICE MISMATCH IN A AG/NI HETEROPHASE BOUNDARY SO PHYSICAL REVIEW B LA English DT Article ID EMBEDDED-ATOM-METHOD; SYSTEMS; NICKEL; FOILS AB Using the embedded-atom method, we model atomistically the compensation of the misfit-induced stresses in a "cube-on-cube" oriented Ag/Ni bicrystal with a (011) interface plane, in which zones of maximum misfit (misfit dislocations) run along the [100] and the [011BAR] directions. The ideal interface corresponds to an abrupt transition between Ag and Ni. The interfacial enthalpy is found to be lowered by the introduction of vacancies on the Ni side (equivalently, vacancies are trapped on the Ni side of the boundary). Pursuing this perspective, we find that the interfacial enthalpy is lowered considerably by the removal of a complete line of Ni atoms along the [011BAR] direction from the Ni side of the boundary. The minimum enthalpy configuration consists of a Ni layer whose atomic density is reduced by 16%, sandwiched between the ordinary Ni and Ag lattices. A detailed analysis of the vacancy-formation process shows that atomic relaxations make the main contribution to the low vacancy-formation enthalpies at the boundary. C1 SANDIA NATL LABS,LIVERMORE,CA 94551. RP GUMBSCH, P (reprint author), MAX PLANCK INST MET RES,INST WERKSTOFFWISSENSCH,W-7000 STUTTGART,GERMANY. RI Gumbsch, Peter/E-5879-2012; OI Gumbsch, Peter/0000-0001-7995-228X; Foiles, Stephen/0000-0002-1907-454X NR 12 TC 33 Z9 33 U1 0 U2 4 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 JUN 15 PY 1991 VL 43 IS 17 BP 13833 EP 13837 DI 10.1103/PhysRevB.43.13833 PG 5 WC Physics, Condensed Matter SC Physics GA FQ974 UT WOS:A1991FQ97400004 ER PT J AU STERNE, PA KAISER, JH AF STERNE, PA KAISER, JH TI 1ST-PRINCIPLES CALCULATION OF POSITRON LIFETIMES IN SOLIDS SO PHYSICAL REVIEW B LA English DT Article ID DENSITY-FUNCTIONAL THEORY; ENERGETIC PROTONS; ANNIHILATION; ELECTRON; INSULATORS; SEMICONDUCTORS; ALUMINUM AB We present a first-principles approach for calculating the positron lifetime in metals. Convenient expressions are provided for the electron-positron correlation function and the enhancement factor. Calculations on a wide range of elemental metals and some monovacancies are found to be in excellent agreement with experiment. The approximations inherent in this approach and the treatment of the core-electron contribution are discussed. C1 UNIV TEXAS,DEPT PHYS,ARLINGTON,TX 76019. RP STERNE, PA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-268,LIVERMORE,CA 94550, USA. NR 28 TC 58 Z9 58 U1 2 U2 6 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 JUN 15 PY 1991 VL 43 IS 17 BP 13892 EP 13898 DI 10.1103/PhysRevB.43.13892 PG 7 WC Physics, Condensed Matter SC Physics GA FQ974 UT WOS:A1991FQ97400008 ER PT J AU TAKEUCHI, N CHAN, CT HO, KM AF TAKEUCHI, N CHAN, CT HO, KM TI AU(111) - A THEORETICAL-STUDY OF THE SURFACE RECONSTRUCTION AND THE SURFACE ELECTRONIC-STRUCTURE SO PHYSICAL REVIEW B LA English DT Article ID NORM-CONSERVING PSEUDOPOTENTIALS; METAL-SURFACES; GOLD; DISLOCATIONS; DIFFRACTION; MICROSCOPY; FACES AB On the reconstructed Au(111) surface, atoms on the surface layer occupy both the hcp and the fcc sites. Using first-principles calculations to obtain the surface energies of the system with the top Au layer occupying the fcc, hcp, top, and bridge sites, we found that the hcp site is only 1 mRy per surface atom higher in energy than the fcc site. The complex Au(111) reconstruction is then discussed with use of a two-dimensional Frenkel-Kontorowa model. We calculated the surface band structure of the Au(111) surface along high-symmetry lines in the surface Brillouin zone, with the top layer occupying the fcc, hcp, and bridge sites. We found that the surface electronic structure is almost independent of the position of the top layer. C1 IOWA STATE UNIV SCI & TECHNOL, DEPT PHYS, AMES, IA 50011 USA. RP IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. RI Takeuchi, Noboru/H-1777-2014 NR 24 TC 114 Z9 115 U1 3 U2 31 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1991 VL 43 IS 17 BP 13899 EP 13906 DI 10.1103/PhysRevB.43.13899 PG 8 WC Physics, Condensed Matter SC Physics GA FQ974 UT WOS:A1991FQ97400009 ER PT J AU OSORIO, R FROYEN, S ZUNGER, A AF OSORIO, R FROYEN, S ZUNGER, A TI STRUCTURAL PHASE-TRANSITION IN (GAAS)1-XGE2X AND (GAP)1-XSI2X ALLOYS - TEST OF THE BULK THERMODYNAMIC DESCRIPTION SO PHYSICAL REVIEW B LA English DT Article ID ORDER-DISORDER TRANSITION; METASTABLE (GAAS)1-X(GE2)X ALLOYS; LONG-RANGE ORDER; SINGLE-CRYSTAL; SEMICONDUCTOR ALLOYS; RAMAN-SCATTERING; SOLID-SOLUTIONS; BAND OFFSETS; ISING-MODEL; PSEUDOPOTENTIAL APPROACH AB Nonisovalent (A(III)B(V)(1-x)C2x(IV) semiconductor alloys exhibit a transition as a function of composition between a phase with the zinc-blende symmetry (where the two fcc sublattices of the diamond lattice are unequally occupied by A(III) and B(V) atoms) and a phase with the diamond symmetry (where the two sublattices have equal occupations). Previous thermodynamic models of this transition have considered only nearest-neighbor interactions between neutral atoms. This approach ignores the important electrostatic interactions associated with electron transfer between the electron-rich C(IV)-B(V) ("donor") bonds and the electron-deficient A(III)-C(IV) ("acceptor") bonds. We have reexamined the validity of a three-dimensional bulk thermodynamic model for (GaAs)(1-x)Ge2x and (GaP)(1-x)Si2x using an energy model that includes such electrostatic interactions and pairwise energies extracted from first-principles local-density total-energy calculations. The associated spin-1 Ising Hamiltonian is solved in the pair approximation of the cluster-variation method. A detailed thermodynamic description is given, including excess enthalpies, phase diagrams, and equilibrium solubilities. Electrostatic interactions stabilize the diamond phase and result in a major increase in the temperature range where both phases are stable. These changes, however, are insufficient to produce a second-order transition at the low (growth) temperatures and intermediate compositions where the transition is observed. While a previous controversy on the validity of thermodynamic models has focused on the question of whether the postulation of A(III)-A(III) and B(V)-B(V) bonds (needed to fit the observed critical compositions in such models) is consistent with independent evidence, we find that, with realistic values for the interaction parameters, the presence or absence of such bonds does not produce any significant change in the phase diagram below melting temperatures. We conclude that bulk thermodynamics is an inappropriate description of the problem. This opens the possibility that surface thermodynamics could be the physical mechanism that determines the final symmetry of the sample. C1 UNIV BRASILIA,DEPT FIS,BR-70910 BRASILIA,DF,BRAZIL. RP OSORIO, R (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013 NR 90 TC 34 Z9 34 U1 1 U2 4 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 JUN 15 PY 1991 VL 43 IS 17 BP 14055 EP 14072 DI 10.1103/PhysRevB.43.14055 PG 18 WC Physics, Condensed Matter SC Physics GA FQ974 UT WOS:A1991FQ97400027 ER PT J AU ZHU, XJ LOUIE, SG AF ZHU, XJ LOUIE, SG TI QUASI-PARTICLE BAND-STRUCTURE OF 13 SEMICONDUCTORS AND INSULATORS SO PHYSICAL REVIEW B LA English DT Article ID DENSITY-FUNCTIONAL THEORY; EXCHANGE-CORRELATION POTENTIALS; NORM-CONSERVING PSEUDOPOTENTIALS; SPECIAL QUASIRANDOM STRUCTURES; STATIC DIELECTRIC MATRICES; SELF-ENERGY OPERATORS; SHAM-FERMI SURFACES; ELECTRONIC-STRUCTURE; DERIVATIVE DISCONTINUITIES; PHOTOEMISSION SPECTROSCOPY AB By using a model dielectric matrix in electron self-energy evaluations the computational effort of a quasiparticle band-structure calculation for a semiconductor is greatly reduced. Applications to various systems with or without inversion symmetry, having narrow or wide band gaps, and semiconductor alloys demonstrate the reliability and accuracy of the method. Calculations have been performed for thirteen semiconducting or insulating materials: Si, LiCl, AIP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, InSb, and the Al0.5Ga0.5As and In0.53Ga0.47As alloys. Excellent agreement with experimental results is obtained for the quasiparticle energies for these materials. The only three exceptions, E(GAMMA-1c) of AlP, E(L1c) of AlAs, and E(L1c) of AlSb are discussed and attributed to various experimental uncertainties. Several other quasiparticle-excitation-related properties are also examined in this work. The many-body corrections to the eigenvalues of the valence-band-maximum states obtained from the local-density approximation are calculated for the zinc-blende-structure semiconductors, which are widely used in semiconductor-interface studies. In the present approach, the static screening of the Coulomb interaction between two electrons in a crystal is determined using a model that depends only on the local charge densities at these two points. Since a direct quantitative modeling of the electron self-energy operator has proven difficult, the successful application of the present model-dielectric-function scheme in self-energy calculations makes possible detailed studies of the quasiparticle properties of rather complex systems, which would be otherwise computationally too demanding. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. NR 97 TC 216 Z9 220 U1 6 U2 28 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1991 VL 43 IS 17 BP 14142 EP 14156 DI 10.1103/PhysRevB.43.14142 PG 15 WC Physics, Condensed Matter SC Physics GA FQ974 UT WOS:A1991FQ97400036 ER PT J AU TAKEUCHI, N CHAN, CT HO, KM AF TAKEUCHI, N CHAN, CT HO, KM TI RECONSTRUCTION OF THE (100) SURFACES OF AU AND AG SO PHYSICAL REVIEW B LA English DT Article ID AU(001) SURFACE; ELECTRONIC-STRUCTURE; METAL SURFACES; GOLD; DIFFRACTION; AU(100); AU(111); PHASES; ENERGY; FACES AB Using first-principles total-energy calculations, together with simulations performed with a Frenkel-Kontorowa model, we show that it is energetically favorable for the top layer of the (100) surface of Au to transform from the ideal square lattice of the (100) surface of a fcc metal to a slightly distorted and contracted hexagonal-close-packed arrangement. The ground-state configuration from our simulation agrees well with experimental observations. The reconstruction is shown to be unfavorable in Ag, which is isoelectronic to Au. The difference in behavior is because the two-dimensional Au layer gains much more energy upon contraction than its Ag counterpart. C1 IOWA STATE UNIV SCI & TECHNOL, DEPT PHYS, AMES, IA 50011 USA. RP IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. RI Takeuchi, Noboru/H-1777-2014 NR 40 TC 53 Z9 53 U1 3 U2 17 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1991 VL 43 IS 18 BP 14363 EP 14370 DI 10.1103/PhysRevB.43.14363 PG 8 WC Physics, Condensed Matter SC Physics GA FW755 UT WOS:A1991FW75500001 ER PT J AU CARTER, PW PORTER, JD AF CARTER, PW PORTER, JD TI PROBING OF PI CONJUGATION IN TRANSPOLYACETYLENE USING NEAR-INFRARED PHOTOLUMINESCENCE SPECTROSCOPY SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-GEOMETRY; CIS-POLYACETYLENE; LENGTH DEPENDENCE; RAMAN-SCATTERING; ISOMERIZATION; LUMINESCENCE; POLYMERS; PHOTOEXCITATIONS; POLYMERIZATION; TRANS-(CH)X AB Near-infrared photoluminescence from undoped trans-polyacetylene was attributed to emission from "cis defects," structures composed of isolated cis-(-CH = CH-) bonds embedded within conjugated trans-(CH)x segments. Spectra were found to be independent of residual transition-metal impurities in the polymer, but quantum efficiencies decreased with increasing concentrations of neutral defects and free carriers. The percolation limit for free carriers was achieved at about 30% overall trans-(CH)x. The photoluminescence energy varied inversely with the length of the conjugated cis defects, with a different dependence than for polyenes in solution. Interchain interactions were found to be significant in the solid state, distorting bonding geometries and perturbing the electronic structure of the chains; we postulate they are essential for bulk conduction. Huckel calculations yielded beta-0 = 1.08 eV for the pi-interaction energy, predicting an energy of 0.39-0.43 eV for the pi-pi* transition of a typical bound neutral soliton. The band gap for trans-polyacetylene of infinite conjugation length was estimated to be 1.20 eV by extrapolation of the solid-state luminescence data. We conclude that thermally isomerized trans-polyacetylene is best described as being a three-dimensional ensemble of short, conjugated segments that are bounded and interconnected by defects and crosslinks. Mean segment lengths are probably less than 13 (-CH = CH-) units. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP CARTER, PW (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. NR 50 TC 21 Z9 22 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 JUN 15 PY 1991 VL 43 IS 18 BP 14478 EP 14487 DI 10.1103/PhysRevB.43.14478 PG 10 WC Physics, Condensed Matter SC Physics GA FW755 UT WOS:A1991FW75500016 ER PT J AU HOLMAN, R KOLB, EW VADAS, SL WANG, Y AF HOLMAN, R KOLB, EW VADAS, SL WANG, Y TI SCALE-INVARIANT EXTENDED INFLATION SO PHYSICAL REVIEW D LA English DT Article ID FALSE-VACUUM DECAY; PHASE-TRANSITION; DENSITY PERTURBATIONS; UNIVERSE SCENARIO; SYMMETRY-BREAKING; COSMOLOGY; PRESCRIPTION; FLUCTUATIONS; BARYOGENESIS; GENERATION AB We propose a model of extended inflation which makes use of the nonlinear realization of scale invariance involving the dilaton coupled to an inflaton field whose potential admits a metastable ground state. The resulting theory resembles the Jordan-Brans-Dicke version of extended inflation. However, quantum effects, in the form of the conformal anomaly, generate a mass for the dilaton, thus allowing our model to evade the problems of the original version of extended inflation. We show that extended inflation can occur for a wide range of inflaton potentials with no fine-tuning of dimensionless parameters required. Furthermore, we also find that it is quite natural for the extended-inflation period to be followed by an epoch of slow-rollover inflation as the dilaton settles down to the minimum of its induced potential. C1 FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP HOLMAN, R (reprint author), CARNEGIE MELLON UNIV,DEPT PHYS,PITTSBURGH,PA 15213, USA. RI Wang, Yun/B-5724-2011 OI Wang, Yun/0000-0002-4749-2984 NR 42 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 15 PY 1991 VL 43 IS 12 BP 3833 EP 3845 DI 10.1103/PhysRevD.43.3833 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FT074 UT WOS:A1991FT07400007 ER PT J AU COOPER, F PEREZMERCADER, J AF COOPER, F PEREZMERCADER, J TI COMPOSITENESS AND THE REDUCTION OF COUPLINGS SO PHYSICAL REVIEW D LA English DT Article ID SYMMETRY-BREAKING; MODEL; RENORMALIZATION AB We study in lowest-order mean-field perturbation theory (the fermion loop approximation) the linear sigma-model in two and four dimensions described by the two couplings lambda and g. We examine the relations obtained by imposing the compositeness conditions Z3 = Z4 = 0 and those obtained by the strategy of trying to reduce the number of coupling constants by looking for a self-consistent solution of the renormalization-group equations for which lambda = f(g2). We find that the reduction-of-couplings strategy gives the same relationship between lambda and g2 as that found by imposing the compositeness conditions. C1 CSIC,E-28006 MADRID,SPAIN. RP COOPER, F (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 13 TC 8 Z9 8 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 JUN 15 PY 1991 VL 43 IS 12 BP 4129 EP 4132 DI 10.1103/PhysRevD.43.4129 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FT074 UT WOS:A1991FT07400036 ER PT J AU TRAVIS, CC MCCLAIN, TW BIRKNER, PD AF TRAVIS, CC MCCLAIN, TW BIRKNER, PD TI DIETHYLNITROSAMINE-INDUCED HEPATOCARCINOGENESIS IN RATS - A THEORETICAL-STUDY SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article ID MOLECULAR DOSIMETRY; CARCINOGENESIS; LIVER; GROWTH; MODEL; DNA; EPIDEMIOLOGY; HEMOGLOBIN; TURNOVER; PROTEIN RP TRAVIS, CC (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OFF RISK ANAL,BLDG 4500S,POB 2008,OAK RIDGE,TN 37831, USA. NR 42 TC 26 Z9 27 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 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD JUN 15 PY 1991 VL 109 IS 2 BP 289 EP 304 DI 10.1016/0041-008X(91)90176-F PG 16 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA FZ043 UT WOS:A1991FZ04300010 PM 1648803 ER PT J AU CHAUDHURI, S DYKSTRA, H LYKKEN, J AF CHAUDHURI, S DYKSTRA, H LYKKEN, J TI THE PENNER MATRIX MODEL AND C = 1 STRINGS SO MODERN PHYSICS LETTERS A LA English DT Article AB The steepest descent solution of the Penner matrix model has a one-cut eigenvalue support. Criticality results when the two branch points of this support coalesce. The support is then a closed contour in the complex eigenvalue plane. Simple generalizations of the Penner model have multi-cut solutions. For these models, the eigenvalue support at criticality is also a closed contour, but consisting of several cuts. We solve the simplest such model, which we call the KT model, in the double-scaling limit. Its free energy is a Legendre transform of the free energy of the c = 1 string compactified to the critical radius of the Kosterlitz-Thouless phase transition. RP CHAUDHURI, S (reprint author), FERMI NATL ACCELERATOR LAB,THEORY GRP,MS106,POB 500,BATAVIA,IL 60510, USA. NR 0 TC 26 Z9 26 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 JUN 14 PY 1991 VL 6 IS 18 BP 1665 EP 1677 DI 10.1142/S0217732391001809 PG 13 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA FW230 UT WOS:A1991FW23000005 ER PT J AU WILLIAMS, JM SCHULTZ, AJ GEISER, U CARLSON, KD KINI, AM WANG, HH KWOK, WK WHANGBO, MH SCHIRBER, JE AF WILLIAMS, JM SCHULTZ, AJ GEISER, U CARLSON, KD KINI, AM WANG, HH KWOK, WK WHANGBO, MH SCHIRBER, JE TI ORGANIC SUPERCONDUCTORS - NEW BENCHMARKS SO SCIENCE LA English DT Review ID AMBIENT-PRESSURE SUPERCONDUCTIVITY; BAND ELECTRONIC-STRUCTURES; NEUTRON-DIFFRACTION EVIDENCE; MOLECULAR SUPERCONDUCTOR; LOW-TEMPERATURE; X-RAY; ELECTRICAL-CONDUCTIVITY; TRANSITION-TEMPERATURE; TRANSPORT-PROPERTIES; CRYSTAL-STRUCTURES AB Recent advances in the design and synthesis of organic synthetic metals have yielded materials that have the highest superconducting transition temperatures (T(c) almost-equal-to 13 kelvin) reported for these systems. These materials have crystal structures consisting of alternating layers of organic donor molecules and inorganic anions. Organic superconductors have various electronic and magnetic properties and crystal structures that are similar to those of the inorganic copper oxide superconductors (which have high T(c) values); these similarities include highly anisotropic conductivities, critical fields, and short coherence lengths. The largest number of organic superconductors, including those with the highest T(c) values, are charge-transfer salts derived from the electron donor molecule BEDT-TTF or ET [bis(ethylenedithio)-tetrathiafulvalene]. The synthesis and crystal structures of these salts are discussed; their electrical, magnetic, and band electronic structure properties and their many similarities to the copper oxide superconductors are treated as well. C1 ARGONNE NATL LAB,DEPT MAT SCI,ARGONNE,IL 60439. N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP WILLIAMS, JM (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Kini, Aravinda/F-4467-2012 NR 127 TC 364 Z9 366 U1 4 U2 75 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 14 PY 1991 VL 252 IS 5012 BP 1501 EP 1508 DI 10.1126/science.252.5012.1501 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FR040 UT WOS:A1991FR04000036 PM 17834875 ER PT J AU LIN, HQ CAMPBELL, DK MAZUMDAR, S AF LIN, HQ CAMPBELL, DK MAZUMDAR, S TI NORMAL STATE BROKEN SYMMETRIES IN QUASI-2-DIMENSIONAL, QUARTER-FILLED CHARGE-TRANSFER SOLIDS SO SYNTHETIC METALS LA English DT Meeting Abstract C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. RP LIN, HQ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 14 PY 1991 VL 43 IS 3 BP 3613 EP 3613 DI 10.1016/0379-6779(91)91643-O PG 1 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA GA284 UT WOS:A1991GA28400007 ER PT J AU BULOU, A DONOHOE, RJ SWANSON, BI AF BULOU, A DONOHOE, RJ SWANSON, BI TI LATTICE-DYNAMICS IN MX CHAINS - LOCALIZED MODES ASSOCIATED WITH POLARONIC AND BIPOLARONIC DEFECTS IN PTX CDW SYSTEMS SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID VALENCE; 4 AB The longitudinal vibrations and the vibrations of valence defects of the PtX linear chains are described in the framework of a one-dimensional model in the first nearest neighbors interaction approximation. The dynamical properties of the perfect chain are parametrized by two force constants K1 (for the Pt(IV)-Cl interaction) and K2 (for the Pt(II)-Cl interaction) and several defects can be described by only one additional parameter, K(d), corresponding to the Pt(III)-X force constant. The set of force constants is chosen in order to obtain a consistent description of the intrinsic frequencies (the omega-1 Raman active mode and two primary infrared active modes) and of the frequencies of the localized modes associated with the defects. A coherent description is obtained for K2/K1 = 0.30 in PtCl and K2/K1 = 0.37 in PtBr, a result consistent with an increase of delocalization from PtCl to PtBr. This analysis supports the assignment of the Raman lines associated with the electron polaron and electron bipolaron in the two materials. C1 UNIV CALIF LOS ALAMOS SCI LAB,INORGAN & STRUCT CHEM GRP INC4,LOS ALAMOS,NM 87545. NR 12 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 14 PY 1991 VL 43 IS 3 BP 3663 EP 3666 DI 10.1016/0379-6779(91)91654-S PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA GA284 UT WOS:A1991GA28400018 ER PT J AU KWOK, RS GRUNER, G BROWN, SE AF KWOK, RS GRUNER, G BROWN, SE TI FLUCTUATIONS AND THERMODYNAMICS OF THE CHARGE-DENSITY WAVE PHASE-TRANSITION OF K0.3MOO3 SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID THERMAL-CONDUCTIVITY; PEIERLS TRANSITION; SUSCEPTIBILITY; (TASE4)2I AB We present results of transport and thermodynamic measurements of the charge-density wave system K0.3MoO3 near the Peierls transition. Resistivity measurements demonstrate that fluctuations intrinsic to the material persist over a broad temperature interval, and a comparison to similar experiments performed on (TaSe4)2I shows that the details are material-dependent. Fluctuations also play an important role in the specific heat C(p) and spin susceptibility-chi, for which C(p) approximately d(chi-T)/dT is observed in the intrinsic regime. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP KWOK, RS (reprint author), UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024, USA. NR 12 TC 1 Z9 1 U1 1 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 14 PY 1991 VL 43 IS 3 BP 3845 EP 3848 DI 10.1016/0379-6779(91)91691-3 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA GA284 UT WOS:A1991GA28400055 ER PT J AU CREAGER, WN RICHARDS, PL ZETTL, A AF CREAGER, WN RICHARDS, PL ZETTL, A TI FAR INFRARED REFLECTANCE AND CONDUCTIVITY OF TAS3 - COMPLETION OF THE AC RESPONSE SPECTRUM SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID RELAXATION; (TASE4)2I; MODE; GAP AB The far infrared reflectance of the charge density wave (CDW) conductor TaS3 has been measured from 3 to 700cm-1 with incident radiation polarized parallel and perpendicular to the long axis of the crystals. For parallel polarization, a strong reflection edge correlated with the formation of the CDW appears near 70cm-1. The associated conductivity shows no dramatic conduction mode in the far infrared. These results are in sharp contrast to the observed behavior in the related CDW materials (TaSe4)2I and K0.3MoO3, and they rule out models of a "generic far infrared mode" in CDW excitations. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP CREAGER, WN (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 10 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 14 PY 1991 VL 43 IS 3 BP 3867 EP 3870 DI 10.1016/0379-6779(91)91697-9 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA GA284 UT WOS:A1991GA28400061 ER PT J AU MAZUMDAR, S LIN, HQ CAMPBELL, DK AF MAZUMDAR, S LIN, HQ CAMPBELL, DK TI THE PHASE-DIAGRAM OF 2-1 CATIONIC ORGANIC CHARGE-TRANSFER SALTS SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID MAGNETORESISTANCE; FIELD AB We propose a new theoretical approach, stressing the role of Coulomb interactions and bandfilling effects, to describe the phase diagram of the 2:1 cationic organic charge transfer salts, including those exhibiting field induced spin density wave (FISDW) behavior. We predict three distinct nonsuperconducting phases. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP MAZUMDAR, S (reprint author), UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721, USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 14 PY 1991 VL 43 IS 3 BP 4047 EP 4050 DI 10.1016/0379-6779(91)91741-R PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA GA284 UT WOS:A1991GA28400105 ER PT J AU CHIPMAN, DM CARMICHAEL, I FELLER, D AF CHIPMAN, DM CARMICHAEL, I FELLER, D TI MOLECULAR-ORBITAL STUDIES OF HYPERFINE COUPLING-CONSTANTS IN THE H2CN AND H(HO)CN RADICALS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID UNRESTRICTED WAVE-FUNCTIONS; ELECTRON-SPIN RESONANCE; ATOMS B-F; CONFIGURATION-INTERACTION; NITROGEN-ATOM; ROW ATOMS; ABINITIO; HYDROGEN; HYDRIDES; CH2N AB Isotropic magnetic hyperfine splittings have been evaluated for the closely related H2CN and H(HO)CN radicals from ab initio molecular orbital models. Uncertainties in the equilibrium geometries appear to have little effect on the carbon and nitrogen splittings but may affect the large methylene hydrogen splittings by up to several gauss. Vibrational averaging is estimated to provide corrections on the order of only 1 G or less at all nuclei. Direct, spin-polarization, and electron correlation effects all contribute about equally to the large methylene hydrogen splitting in each radical, as well as to the large difference in this splitting between the two radicals. The electron correlation contribution is the most difficult to calculate, and neither of the two distinct procedures utilized to study that effect provides a fully quantitative description at the limit of currently feasible calculations. C1 PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. RP CHIPMAN, DM (reprint author), UNIV NOTRE DAME, RADIAT LAB, NOTRE DAME, IN 46556 USA. RI Chipman, Daniel/C-7704-2015 OI Chipman, Daniel/0000-0002-9992-6684 NR 43 TC 45 Z9 46 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 13 PY 1991 VL 95 IS 12 BP 4702 EP 4708 DI 10.1021/j100165a021 PG 7 WC Chemistry, Physical SC Chemistry GA FR756 UT WOS:A1991FR75600021 ER PT J AU GLEZEN, MM JONAH, CD AF GLEZEN, MM JONAH, CD TI PULSE-RADIOLYSIS OF CR(CO)6 AND W(CO)6 IN ALKANE SOLUTION SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID CARBONYL-COMPLEXES; TUNGSTEN HEXACARBONYL; EXCITED-STATES; CYCLOHEXANE; PHOTOLYSIS; ELECTRON; LIQUID; PHOTODISSOCIATION; PHOTOCHEMISTRY; PENTACARBONYL AB Pulse radiolysis of Cr(CO)6 and W(CO)6 in alkane solution is described. The first reaction is identified as electron capture and yields the transients Cr(CO)5.- and W(CO)5.- (lambda-max = 720 nm). Formation rates of Cr(CO)5S and W(CO)5S are measured and the main mechanism is identified as geminate reaction between the anion formed and a cation of the solvent. Behavior in the presence and absence of electron scavengers is described as well. The absorption spectrum of Cr(CO)5.- in ethanol is also recorded ((lambda-max > 1000 nm). C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 51 TC 3 Z9 3 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 13 PY 1991 VL 95 IS 12 BP 4736 EP 4741 DI 10.1021/j100165a027 PG 6 WC Chemistry, Physical SC Chemistry GA FR756 UT WOS:A1991FR75600027 ER PT J AU AEPPLI, A WYLER, D AF AEPPLI, A WYLER, D TI HARD BREMSSTRAHLUNG PROCESSES AT LEP-II SO PHYSICS LETTERS B LA English DT Article ID W-PAIR PRODUCTION; RADIATIVE-CORRECTIONS; HIGH-ENERGIES; MULTIPLE BREMSSTRAHLUNG; GAUGE-THEORIES; AMPLITUDES; E+E-->W+W AB The matrix element for single hard photon bremsstrahlung in the dominant LEP II process e+e- --> W+W- --> 4f with massless fermions is given. An appropriate Monte Carlo event generator is described and the results for total cross sections and the photon spectrum are presented. The narrow width approximation for the W and the background are discussed. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP AEPPLI, A (reprint author), UNIV ZURICH,INST THEORET PHYS,CH-8001 ZURICH,SWITZERLAND. NR 28 TC 25 Z9 25 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 13 PY 1991 VL 262 IS 1 BP 125 EP 134 DI 10.1016/0370-2693(91)90655-A PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU463 UT WOS:A1991FU46300023 ER PT J AU DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A CATANESI, MG CREANZA, D DE PALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BROWN, D BURNETT, TH DREVERMANN, H DYDAK, F FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S HILGART, J JOST, B KASEMANN, M KNOBLOCH, J LACOURT, A LANCON, E LEHRAUS, I LOHSE, T MARCHIORO, A MARTINEZ, M MENARY, S MINTEN, A MIOTTO, A MIGUEL, R MOSER, HG NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROTH, A ROTHBERG, J ROTSCHEIDT, H ST DENIS, R SCHLATTER, D TAKASHIMA, M TALBY, M TEJESSY, W WACHSMUTH, H WASSERBAECH, S WHEELER, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BARDADIN-OTWINOWSKA, M FALVARD, A EL FELLOUS, R GAY, P HARVEY, J HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NIELSEN, ER NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BOUROTTE, J BRAEMS, F BRIENT, JC FOUQUE, G GAMESS, A GUIRLET, R ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CHIARELLA, V D'ETTORRE-PIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP NICOLETTI, G PASSALACQUA, L PEPE-ALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O HALLEY, AW TEN HAVE, I HEARNS, JL LYNCH, JG MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D Rudolph, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G KEEMER, NR NUTTALL, M PATEL, A ROWLINGSON, BS SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T BAUERDICK, LAT KLEINKNECHT, K RENK, B ROEHN, S SANDER, HG SCHMELLING, M SCHMIDT, H STEEG, F ALBANESE, JP AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A COURVOISIER, D ETIENNE, F PAPALEXIOU, S PAYRE, P PIETRZYK, B QIAN, Z BECKER, H BLUM, W CATTANEO, P COWAN, G DEHNING, B DIETL, H FERNANDEZ-BOSMAN, M HANSL-KOZANECKA, T JAHN, A KOZANECKI, W LANGE, E LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GANIS, G GRIVAZ, JF HEUSSE, PH JANOT, P KIM, DW LE DIBERDER, F LEFRANCOIS, J LUTZ, AM VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELL'ORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GIASSI, A GIORGI, MA LIGABUE, F LUSIANI, A MANNELLI, EB MARROCCHESI, PS MESSINEO, A MONETA, L PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, GM MARCH, PV MEDCALF, T QUAZI, IS SAICH, MR STRONG, JA THOMAS, RM WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCH-DEVAUX, B COLAS, P KLOPFENSTEIN, C LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERLAS, JA PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J VALLAGE, B ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, R CARTWRIGHT, S COMBLEY, F DINSDALE, M DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BRANDT, S BURKHARDT, H GRUPEN, C MEINHARD, H MIRABITO, L NEUGEBAUER, E SCHAFER, U SEYWERD, H APOLLINARI, G GIANNINI, G GOBBO, B LIELLO, F RAGUSA, F ROLANDI, L STIEGLER, U BELLANTONI, L BOUDREAU, JF CINABRO, D CONWAY, JS COWEN, DF DEWEERD, AJ FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JACOBSEN, JE JARED, RC JOHNSON, RP LECLAIRE, BW PAN, YB PATER, JR SAADI, Y SHARMA, V WALSH, AM WEAR, JA WEBER, FV WHITNEY, MH WU, SL ZHOU, ZL ZOBERNIG, G AF DECAMP, D DESCHIZEAUX, B GOY, C LEES, JP MINARD, MN ALEMANY, R CRESPO, JM DELFINO, M FERNANDEZ, E GAITAN, V GARRIDO, L MIR, LM PACHECO, A CATANESI, MG CREANZA, D DE PALMA, M FARILLA, A IASELLI, G MAGGI, G MAGGI, M NATALI, S NUZZO, S QUATTROMINI, M RANIERI, A RASO, G ROMANO, F RUGGIERI, F SELVAGGI, G SILVESTRIS, L TEMPESTA, P ZITO, G GAO, Y HU, H HUANG, D HUANG, X LIN, J LOU, J QIAO, C RUAN, T WANG, T XIE, Y XU, D XU, R ZHANG, J ZHAO, W ATWOOD, WB BIRD, F BLUCHER, E BONVICINI, G BOSSI, F BROWN, D BURNETT, TH DREVERMANN, H DYDAK, F FORTY, RW GRAB, C HAGELBERG, R HAYWOOD, S HILGART, J JOST, B KASEMANN, M KNOBLOCH, J LACOURT, A LANCON, E LEHRAUS, I LOHSE, T MARCHIORO, A MARTINEZ, M MENARY, S MINTEN, A MIOTTO, A MIGUEL, R MOSER, HG NASH, J PALAZZI, P RANJARD, F REDLINGER, G ROTH, A ROTHBERG, J ROTSCHEIDT, H ST DENIS, R SCHLATTER, D TAKASHIMA, M TALBY, M TEJESSY, W WACHSMUTH, H WASSERBAECH, S WHEELER, S WIEDENMANN, W WITZELING, W WOTSCHACK, J AJALTOUNI, Z BARDADIN-OTWINOWSKA, M FALVARD, A EL FELLOUS, R GAY, P HARVEY, J HENRARD, P JOUSSET, J MICHEL, B MONTRET, JC PALLIN, D PERRET, P PRORIOL, J PRULHIERE, F STIMPFL, G HANSEN, JD HANSEN, JR HANSEN, PH MOLLERUD, R NIELSEN, ER NILSSON, BS EFTHYMIOPOULOS, I SIMOPOULOU, E VAYAKI, A BADIER, J BLONDEL, A BONNEAUD, G BOUROTTE, J BRAEMS, F BRIENT, JC FOUQUE, G GAMESS, A GUIRLET, R ORTEU, S ROSOWSKY, A ROUGE, A RUMPF, M TANAKA, R VIDEAU, H CANDLIN, DJ VEITCH, E PARRINI, G CORDEN, M GEORGIOPOULOS, C IKEDA, M LANNUTTI, J LEVINTHAL, D MERMIKIDES, M SAWYER, L ANTONELLI, A BALDINI, R BENCIVENNI, G BOLOGNA, G CAMPANA, P CAPON, G CHIARELLA, V D'ETTORRE-PIAZZOLI, B FELICI, G LAURELLI, P MANNOCCHI, G MURTAS, F MURTAS, GP NICOLETTI, G PASSALACQUA, L PEPE-ALTARELLI, M PICCHI, P ZOGRAFOU, P ALTOON, B BOYLE, O HALLEY, AW TEN HAVE, I HEARNS, JL LYNCH, JG MORTON, WT RAINE, C SCARR, JM SMITH, K THOMPSON, AS TURNBULL, RM BRANDL, B BRAUN, O GEIGES, R GEWENIGER, C HANKE, P HEPP, V KLUGE, EE MAUMARY, Y PUTZER, A RENSCH, B STAHL, A TITTEL, K WUNSCH, M BELK, AT BEUSELINCK, R BINNIE, DM CAMERON, W CATTANEO, M DORNAN, PJ DUGEAY, S GREENE, AM HASSARD, JF LIESKE, NM PATTON, SJ PAYNE, DG PHILLIPS, MJ SEDGBEER, JK TAYLOR, G TOMALIN, IR WRIGHT, AG GIRTLER, P KUHN, D Rudolph, G BOWDERY, CK BRODBECK, TJ FINCH, AJ FOSTER, F HUGHES, G KEEMER, NR NUTTALL, M PATEL, A ROWLINGSON, BS SLOAN, T SNOW, SW WHELAN, EP BARCZEWSKI, T BAUERDICK, LAT KLEINKNECHT, K RENK, B ROEHN, S SANDER, HG SCHMELLING, M SCHMIDT, H STEEG, F ALBANESE, JP AUBERT, JJ BENCHOUK, C BERNARD, V BONISSENT, A COURVOISIER, D ETIENNE, F PAPALEXIOU, S PAYRE, P PIETRZYK, B QIAN, Z BECKER, H BLUM, W CATTANEO, P COWAN, G DEHNING, B DIETL, H FERNANDEZ-BOSMAN, M HANSL-KOZANECKA, T JAHN, A KOZANECKI, W LANGE, E LAUBER, J LUTJENS, G LUTZ, G MANNER, W PAN, Y RICHTER, R SCHRODER, J SCHWARZ, AS SETTLES, R STIERLIN, U THOMAS, J WOLF, G BERTIN, V BOUCROT, J CALLOT, O CHEN, X CORDIER, A DAVIER, M GANIS, G GRIVAZ, JF HEUSSE, PH JANOT, P KIM, DW LE DIBERDER, F LEFRANCOIS, J LUTZ, AM VEILLET, JJ VIDEAU, I ZHANG, Z ZOMER, F AMENDOLIA, SR BAGLIESI, G BATIGNANI, G BOSISIO, L BOTTIGLI, U BRADASCHIA, C CARPINELLI, M CIOCCI, MA DELL'ORSO, R FERRANTE, I FIDECARO, F FOA, L FOCARDI, E FORTI, F GIASSI, A GIORGI, MA LIGABUE, F LUSIANI, A MANNELLI, EB MARROCCHESI, PS MESSINEO, A MONETA, L PALLA, F SANGUINETTI, G STEINBERGER, J TENCHINI, R TONELLI, G TRIGGIANI, G VANNINI, C VENTURI, A VERDINI, PG WALSH, J CARTER, JM GREEN, GM MARCH, PV MEDCALF, T QUAZI, IS SAICH, MR STRONG, JA THOMAS, RM WEST, LR WILDISH, T BOTTERILL, DR CLIFFT, RW EDGECOCK, TR EDWARDS, M FISHER, SM JONES, TJ NORTON, PR SALMON, DP THOMPSON, JC BLOCH-DEVAUX, B COLAS, P KLOPFENSTEIN, C LOCCI, E LOUCATOS, S MONNIER, E PEREZ, P PERLAS, JA PERRIER, F RANDER, J RENARDY, JF ROUSSARIE, A SCHULLER, JP SCHWINDLING, J VALLAGE, B ASHMAN, JG BOOTH, CN BUTTAR, C CARNEY, R CARTWRIGHT, S COMBLEY, F DINSDALE, M DOGRU, M HATFIELD, F MARTIN, J PARKER, D REEVES, P THOMPSON, LF BRANDT, S BURKHARDT, H GRUPEN, C MEINHARD, H MIRABITO, L NEUGEBAUER, E SCHAFER, U SEYWERD, H APOLLINARI, G GIANNINI, G GOBBO, B LIELLO, F RAGUSA, F ROLANDI, L STIEGLER, U BELLANTONI, L BOUDREAU, JF CINABRO, D CONWAY, JS COWEN, DF DEWEERD, AJ FENG, Z FERGUSON, DPS GAO, YS GRAHL, J HARTON, JL JACOBSEN, JE JARED, RC JOHNSON, RP LECLAIRE, BW PAN, YB PATER, JR SAADI, Y SHARMA, V WALSH, AM WEAR, JA WEBER, FV WHITNEY, MH WU, SL ZHOU, ZL ZOBERNIG, G CA ALEPH COLLABORATION TI SEARCH FOR A NEW WEAKLY INTERACTING PARTICLE SO PHYSICS LETTERS B LA English DT Article AB A search for events of the type e+e- --> l+l-X0, where X0 can be any weakly interacting particle which couples to the Z, has been performed with the ALEPH detector at LEP, by searching for acollinear lepton pairs. Such particles can be excluded up to a mass of 7.0 GeV/c2 for a value of the ratio of branching fractions, Br(Z --> X0l+l-)/Br(Z --> l+l-), greater than 2.5 X 10(-3) if the X0 has third component of isospin, I3 greater than 1/2 and decays to a pair of virtual gauge bosons. When this analysis is combined with the previous results of the Higgs particle searches from ALEPH, this limit can be extended to an X0 mass of 60 GeV/c2. C1 CNRS, IN2P3, LAB PHYS PARTICULES, F-74019 ANNECY LE VIEUX, FRANCE. UNIV AUTONOMA BARCELONA, LAB FIS ALTA ENERGIES, E-08193 BELLATERRA BARCELONA, SPAIN. IST NAZL FIS NUCL, SEZ BARI, I-70126 BARI, ITALY. UNIV BARI, DIPARTIMENTO FIS, I-70126 BARI, ITALY. ACAD SINICA, INST HIGH ENERGY PHYS, BEIJING, PEOPLES R CHINA. CERN, EUROPEAN LAB PARTICLE PHYS, CH-1211 GENEVA 23, SWITZERLAND. UNIV BLAISE PASCAL, LAB PHYS CORPUSCULAIRE, F-63177 AUBIERE, FRANCE. NIELS BOHR INST, DK-2100 COPENHAGEN, DENMARK. NUCL RES CTR DEMOKRITOS, GR-15310 ATHENS, GREECE. ECOLE POLYTECH, CNRS, IN2P3, LAB PHYS NUCL & HAUTES ENERGIES, F-91128 PALAISEAU, FRANCE. UNIV EDINBURGH, DEPT PHYS, EDINBURGH EH9 3JZ, MIDLOTHIAN, SCOTLAND. UNIV FIRENZE, DIPARTIMENTO FIS, I-50125 FLORENCE, ITALY. IST NAZL FIS NUCL, SEZ FIRENZE, I-50125 FLORENCE, ITALY. FLORIDA STATE UNIV, SUPERCOMP COMPUTAT RES INST, TALLAHASSEE, FL 32306 USA. FLORIDA STATE UNIV, DEPT PHYS, TALLAHASSEE, FL 32306 USA. IST NAZL FIS NUCL, LNF, I-00044 FRASCATI, ITALY. UNIV GLASGOW, DEPT PHYS & ASTRON, GLASGOW G12 8QQ, LANARK, SCOTLAND. UNIV HEIDELBERG, INST HOCHENERGIEPHYS, W-6900 HEIDELBERG, GERMANY. IMPERIAL COLL, DEPT PHYS, London SW7 2BZ, ENGLAND. UNIV INNSBRUCK, INST EXPT PHYS, A-6020 INNSBRUCK, AUSTRIA. UNIV LANCASTER, DEPT PHYS, LANCASTER LA1 4YB, ENGLAND. UNIV MAINZ, INST PHYS, W-6500 MAINZ, GERMANY. CNRS, IN2P3, FAC SCI LUMINY, CTR PHYS PARTICULES, F-13288 MARSEILLE, FRANCE. WERNER HEISENBERG INST PHYS, MAX PLANCK INST PHYS & ASTROPHYS, W-8000 MUNICH, GERMANY. UNIV PARIS SUD, CNRS, IN2P3, LAB ACCELERATEUR LINEAIRE, F-91405 ORSAY, FRANCE. UNIV PISA, DIPARTIMENTO FIS, INFN, SEZ PISA, I-56010 PISA, ITALY. SCUOLA NORMALE SUPER, I-56010 PISA, ITALY. UNIV LONDON, ROYAL HOLLOWAY & BEDFORD NEW COLL, DEPT PHYS, SURREY TW20 0EX, ENGLAND. RUTHERFORD APPLETON LAB, PARTICLE PHYS DEPT, Didcot OX11 0QX, Oxon, ENGLAND. CEN SACLAY, DEPT PHYS PARTICULES ELEMENTAIRES, F-91191 GIF SUR YVETTE, FRANCE. UNIV SHEFFIELD, DEPT PHYS, SHEFFIELD S3 7RH, ENGLAND. UNIV SIEGEN, FACHBEREICH PHYS, W-5900 SIEGEN, GERMANY. UNIV TRIESTE, DIPARTIMENTO FIS, I-34127 TRIESTE, ITALY. IST NAZL FIS NUCL, SEZ TRIESTE, I-34127 TRIESTE, ITALY. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. SLAC, STANFORD, CA 94309 USA. UNIV WASHINGTON, SEATTLE, WA 98195 USA. FAC SCI, CTR PHYS PARTICULES, F-13288 MARSEILLE 9, FRANCE. UNIV TORINO, IST FIS GEN, I-10124 TURIN, ITALY. CNR, IST COSMO GEOFIS, I-10133 TURIN, ITALY. LBL, BERKELEY, CA 94720 USA. RP DECAMP, D (reprint author), CNRS, IN2P3, LAB PHYS PARTICULES, F-74019 ANNECY LE VIEUX, FRANCE. RI Murtas, Fabrizio/B-5729-2012; Booth, Christopher/B-5263-2016; Delfino, Manuel/A-1545-2012; Pacheco Pages, Andres/C-5353-2011; Ferrante, Isidoro/F-1017-2012; Ligabue, Franco/F-3432-2014; Venturi, Andrea/J-1877-2012; Perrier, Frederic/A-5953-2011; Rolandi, Luigi (Gigi)/E-8563-2013; Colas, Paul/F-2876-2013; Bosman, Martine/J-9917-2014; Fernandez, Enrique/L-5387-2014; Mir, Lluisa-Maria/G-7212-2015; ciocci, maria agnese /I-2153-2015; Lusiani, Alberto/N-2976-2015; Marrocchesi, Pier Simone/N-9068-2015; Forti, Francesco/H-3035-2011; Lusiani, Alberto/A-3329-2016 OI Murtas, Fabrizio/0000-0002-7041-6541; Garrido Beltran, Lluis/0000-0001-8883-6539; Edgecock, Rob/0000-0002-7896-3312; Miquel, Ramon/0000-0002-6610-4836; Booth, Christopher/0000-0002-6051-2847; Delfino, Manuel/0000-0002-9468-4751; Pacheco Pages, Andres/0000-0001-8210-1734; Ferrante, Isidoro/0000-0002-0083-7228; Palazzi, Paolo/0000-0002-4861-391X; RASO, Giuseppe/0000-0002-5660-3711; Bottigli, Ubaldo/0000-0002-0666-3433; Ligabue, Franco/0000-0002-1549-7107; Bloch-Devaux, Brigitte/0000-0002-2463-1232; Rolandi, Luigi (Gigi)/0000-0002-0635-274X; Bosman, Martine/0000-0002-7290-643X; Fernandez, Enrique/0000-0002-6405-9488; Mir, Lluisa-Maria/0000-0002-4276-715X; ciocci, maria agnese /0000-0003-0002-5462; Lusiani, Alberto/0000-0002-6876-3288; Marrocchesi, Pier Simone/0000-0003-1966-140X; Forti, Francesco/0000-0001-6535-7965; Lusiani, Alberto/0000-0002-6876-3288 NR 11 TC 7 Z9 7 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 13 PY 1991 VL 262 IS 1 BP 139 EP 147 DI 10.1016/0370-2693(91)90657-C PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FU463 UT WOS:A1991FU46300025 ER PT J AU GEISER, U WANG, HH CARLSON, KD WILLIAMS, JM CHARLIER, HA HEINDL, JE YACONI, GA LOVE, BJ LATHROP, MW SCHIRBER, JE OVERMYER, DL REN, JQ WHANGBO, MH AF GEISER, U WANG, HH CARLSON, KD WILLIAMS, JM CHARLIER, HA HEINDL, JE YACONI, GA LOVE, BJ LATHROP, MW SCHIRBER, JE OVERMYER, DL REN, JQ WHANGBO, MH TI SUPERCONDUCTIVITY AT 2.8-K AND 1.5-KBAR IN KAPPA-(BEDT-TTF)2CU2(CN)3 - THE 1ST ORGANIC SUPERCONDUCTOR CONTAINING A POLYMERIC COPPER CYANIDE ANION SO INORGANIC CHEMISTRY LA English DT Note ID BAND ELECTRONIC-STRUCTURES; TRANSITION-TEMPERATURE; PRESSURE; CRYSTAL; CHAIN; SALTS; TC C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. N CAROLINA STATE UNIV,DEPT CHEM,RALEIGH,NC 27695. RP GEISER, U (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 28 TC 90 Z9 90 U1 2 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JUN 12 PY 1991 VL 30 IS 12 BP 2586 EP 2588 DI 10.1021/ic00012a005 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA FR045 UT WOS:A1991FR04500005 ER PT J AU MOONEY, GD HERMANN, AM TUTTLE, JR ALBIN, DS NOUFI, R AF MOONEY, GD HERMANN, AM TUTTLE, JR ALBIN, DS NOUFI, R TI FORMATION OF CUINSE2 THIN-FILMS BY RAPID THERMAL RECRYSTALLIZATION SO APPLIED PHYSICS LETTERS LA English DT Article ID CULNSE2 AB Polycrystalline thin-film CuInSe2 has been formed by rapid thermal processing of vacuum codeposited Cu, In, and Se. Films were fabricated and characterized in three composition regions: Cu-poor (approximately 20 at. % Cu), stoichiometric (25 at. %), and Cu-rich (approximately 28 at. %). Characterization results are presented including x-ray diffraction analysis, electron probe for microanalysis, scanning electron microscopy, and optical reflection and transmission measurements. Results show that nearly single-phase material has been formed from codeposited precursors with a post-deposition annealing time of less than 2 min. The films have optical absorption coefficients in the high 10(4) cm-1 range with minimum subgap absorption, and an optical band gap of 1.0 eV with smooth morphologies amenable to photovoltaic device fabrication. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP MOONEY, GD (reprint author), UNIV COLORADO,DEPT PHYS,BOULDER,CO 80309, USA. NR 13 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 10 PY 1991 VL 58 IS 23 BP 2678 EP 2680 DI 10.1063/1.104805 PG 3 WC Physics, Applied SC Physics GA FP869 UT WOS:A1991FP86900033 ER PT J AU WEI, SH ZUNGER, A AF WEI, SH ZUNGER, A TI PROPOSAL FOR III-V ORDERED ALLOYS WITH INFRARED BAND-GAPS SO APPLIED PHYSICS LETTERS LA English DT Article ID STRAINED-LAYER SUPERLATTICES; SUPER-LATTICE; WAVELENGTH; DETECTORS; EPITAXY AB It is shown theoretically that the recently observed spontaneous ordering of III-V alloys that yields alternate monolayer (111) superlattices provides the opportunity for achieving infrared band gaps in systems such as (InAs)1(InSb)1 and (GaSb)1(InSb)1. A substantial reduction in the direct band gap is predicted to result from the L-point folding that repel the GAMMA-band-edge states. RP WEI, SH (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013 NR 19 TC 52 Z9 52 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 10 PY 1991 VL 58 IS 23 BP 2684 EP 2686 DI 10.1063/1.104807 PG 3 WC Physics, Applied SC Physics GA FP869 UT WOS:A1991FP86900035 ER PT J AU HAWKINS, GW ZUCKERMAN, B AF HAWKINS, GW ZUCKERMAN, B TI SPATIAL STUDIES OF PLANETARY-NEBULAE WITH IRAS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SOURCES; INTERSTELLAR, GRAINS; NEBULAE, PLANETARY ID SUBMILLIMETER OBSERVATIONS; EVOLVED STARS; MASS-LOSS; O-III; LINE; DUST; RESTORATION; MAGNITUDES; DISTANCES; NGC-7027 AB The infrared sizes at the four IRAS wavelengths of 57 planetaries, most with 20"-60" optical size, are derived from spatial deconvolution of one-dimensional survey mode scans. Survey observations from multiple detectors and hours confirmed (HCON) observations are combined to increase the sampling to a rate that is sufficient for successful deconvolution. The Richardson-Lucy deconvolution algorithm is used to obtain an increase in resolution of a factor of about 2 or 3 from the normal IRAS detector sizes of 45", 45", 90", and 180" at wavelengths 12, 25, 60, and 100-mu-m. Most of the planetaries deconvolve at 12 and 25-mu-m to sizes equal to or smaller than the optical size. Some of the planetaries with optical rings 60" or more in diameter show double-peaked IRAS profiles. Many, such as NGC 6720 and NGC 6543, show all infrared sizes equal to the optical size, while others indicate increasing infrared size with wavelength. Deconvolved IRAS profiles are presented for the 57 planetaries at nearly all wavelengths where IRAS flux densities are 1-2 Jy or higher. Simple models show that the one-dimensional 60-mu-m planetary nebula profiles are more sensitive to the density of the dust grains than to their temperatures. For small nebulae less than 60" in diameter, the models are unable to identify the dust-grain heating sources as due to Lyman-alpha or stellar continuum radiation, but the large nebulae NGC 2438 and NGC 6720 are fitted best with Lyman-alpha or dust-grain emissivity index p = 2 stellar heating models. The 60-mu-m emission profiles for the extended nebulae cannot be fitted with a r-2 dust-grain density law, but are consistent with a dust-grain density distribution versus radius similar in shape to the gas density, implying that the dust grains are mixed with the ionized gas in the same region. Simulated profiles of nebulae with halos of 30"-1' radius whose existences are deduced from optical observations are more consistent with IRAS observations when the halos are included in the modeling. Large 2'-3' radius infrared halos are detected in the IRAS data only for the peculiar nebula CN 1-1, where its 4-degrees Galactic latitude makes a true halo interpretation questionable. C1 UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. RP HAWKINS, GW (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT GEOPHYS & PLANETARY PHYS,POB 808,L-413,LIVERMORE,CA 94550, USA. NR 60 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1991 VL 374 IS 1 BP 227 EP 247 DI 10.1086/170112 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FP765 UT WOS:A1991FP76500022 ER PT J AU MCBREEN, J OGRADY, WE TOURILLON, G DARTYGE, E FONTAINE, A AF MCBREEN, J OGRADY, WE TOURILLON, G DARTYGE, E FONTAINE, A TI XANES STUDY OF UNDERPOTENTIAL DEPOSITED COPPER ON CARBON-SUPPORTED PLATINUM SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article ID RAY ABSORPTION-SPECTROSCOPY; AD-ATOMS; ELECTROCHEMICAL INTERFACES; STRUCTURAL INVESTIGATIONS; ELECTROSORPTION VALENCY; SYNCHROTRON RADIATION; ELECTRONIC-STRUCTURE; QUARTZ MICROBALANCE; SURFACE EXAFS; CU AB Underpotential deposited (UPD) copper on carbon-supported platinum was investigated in-situ in 0.5 M H2SO4 at 0.05 V (SCE) by XANES (X-ray Absorption Near Edge Structure). By taking XANES spectra at the Cu K-edge and the Pt L(III)-edge it was possible to determine the valence state of the copper and observe modifications in the electronic structure of the platinum on adsorption of copper. The XANES for UPD copper shows that the adsorbed copper had an oxidation state close to Cu+. XANES features indicate strongly a tetrahedral coordination for the adsorbed Cu species. A reduction in intensity of the white line in the platinum XANES is consistent with a partial filling of empty Pt d-band vacancies on adsorption of copper. Thus, UPD species can modify the electronic structure of a platinum catalyst. The adsorbed Cu+ species are apparently associated with HSO4- ions. C1 USN,RES LAB,CODE 6170,WASHINGTON,DC 20375. CNRS,LAB UTILISAT RAYONNEMENT ELETROMAGNET,F-91405 ORSAY,FRANCE. RP MCBREEN, J (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 66 TC 44 Z9 44 U1 0 U2 11 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 10 PY 1991 VL 307 IS 1-2 BP 229 EP 240 DI 10.1016/0022-0728(91)85551-Y PG 12 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA FU672 UT WOS:A1991FU67200018 ER PT J AU INGERSOLL, D HUSKISSON, DH AF INGERSOLL, D HUSKISSON, DH TI PREPARATION OF DOPED CARBON-FILMS SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Note RP INGERSOLL, D (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUN 10 PY 1991 VL 307 IS 1-2 BP 281 EP 285 DI 10.1016/0022-0728(91)85556-5 PG 5 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA FU672 UT WOS:A1991FU67200023 ER PT J AU ABE, F AF ABE, F TI MEASUREMENT OF THE W-BOSON PT DISTRIBUTION IN PBARP COLLISIONS AT SQUARE-ROOT-S = 1.8 TEV SO PHYSICAL REVIEW LETTERS LA English DT Article ID JET AB Using the Collider Detector at Fermilab, the W-boson differential cross section d-sigma/dP(T) is measured using W --> ev events in proton-antiproton collisions at square-root s = 1.8 TeV. A next-to-leading-order theoretical calculation agrees well with the data. The cross section (sigma) for P(T) > 50 GeV/c is measured to be 423 +/- 58(stat) +/- 108(syst) pb. RP ABE, F (reprint author), ARGONNE NATL LAB, ARGONNE, IL 60439 USA. NR 15 TC 38 Z9 38 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 2951 EP 2955 DI 10.1103/PhysRevLett.66.2951 PG 5 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100004 ER PT J AU KRAVIS, SD CHURCH, DA JOHNSON, BM MERON, M JONES, KW LEVIN, J SELLIN, IA AZUMA, Y MANSOUR, NB BERRY, HG DRUETTA, M AF KRAVIS, SD CHURCH, DA JOHNSON, BM MERON, M JONES, KW LEVIN, J SELLIN, IA AZUMA, Y MANSOUR, NB BERRY, HG DRUETTA, M TI INNER-SHELL PHOTOIONIZATION OF STORED POSITIVE-IONS USING SYNCHROTRON RADIATION SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHOTOIONISATION CROSS-SECTIONS; HIGHLY-CHARGED IONS; ABSOLUTE AB We have measured the distribution of photoion charge states resulting from vacancy cascades and electron shakeoff following K-shell photoionization of Ar2+ ions. The Ar2+ ions were produced by electron-impact ionization of Ar, stored in a Penning ion trap, and then photoionized using broadband synchrotron radiation. Time-reversed integration of coupled differential equations were used to account for contributions from electron capture with residual gas. The results are in reasonable agreement with a simple theoretical prediction. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. UNIV TENNESSEE,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV ST ETIENNE,TRAITEMENT SIGNAL & INSTRUMENTAT LAB,F-42100 ST ETIENNE,FRANCE. RP KRAVIS, SD (reprint author), TEXAS A&M UNIV SYST,DEPT PHYS,COLLEGE STN,TX 77843, USA. NR 18 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 2956 EP 2959 DI 10.1103/PhysRevLett.66.2956 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100005 ER PT J AU CHENG, KT JOHNSON, WR SAPIRSTEIN, J AF CHENG, KT JOHNSON, WR SAPIRSTEIN, J TI SCREENED LAMB SHIFT CALCULATIONS FOR LITHIUM-LIKE URANIUM, SODIUM-LIKE PLATINUM, AND COPPER-LIKE GOLD SO PHYSICAL REVIEW LETTERS LA English DT Article ID PERTURBATION-THEORY CALCULATIONS; HYDROGEN-LIKE ATOMS; ENERGY-LEVELS; ISOELECTRONIC SEQUENCE; QED CONTRIBUTIONS; IONS; TRANSITIONS AB Calculations of the screened electron self-energy are carried out in local central potentials that approximate a Hartree-Fock potential. The resulting energy corrections are combined with screened vacuum-polarization calculations and used to predict the Lamb shift for n = 2 states of lithiumlike uranium, n = 3 states of sodiumlike platinum, and n = 4 states of copperlike gold. The theoretical values of the screened Lamb shift are found to be in good agreement with values inferred from experiments. C1 UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556. RP CHENG, KT (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 24 TC 71 Z9 72 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 2960 EP 2963 DI 10.1103/PhysRevLett.66.2960 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100006 ER PT J AU STEVENS, MJ ROBBINS, MO BELAK, JF AF STEVENS, MJ ROBBINS, MO BELAK, JF TI SHEAR MELTING OF COLLOIDS - A NONEQUILIBRIUM PHASE-DIAGRAM SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-DYNAMICS; CRYSTALS; SUSPENSIONS; SYSTEMS; MOTION; FLUIDS; FLOW AB Experiments show that charge-stabilized colloidal suspensions form crystals which can melt by applied shear stress. We present a molecular-dynamics simulation study of shear melting in colloids. The non-equilibrium phase diagram is calculated for a volume fraction which has an equilibrium fcc structure. The mechanism for flow in the sheared solid is found to be planes sliding over planes. We find that weak equilibrium solids (high added salt) shear melt, but strong equilibrium solids do not. Instead, shear produces a crossover to a new solid structure. This appears in the phase diagram as a reentrant solid phase. Results for shear stress and phase diagram are consistent with existing experiments. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP STEVENS, MJ (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. NR 24 TC 77 Z9 77 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 3004 EP 3007 DI 10.1103/PhysRevLett.66.3004 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100017 ER PT J AU MORIARTY, JA PHILLIPS, R AF MORIARTY, JA PHILLIPS, R TI 1ST-PRINCIPLES INTERATOMIC POTENTIALS FOR TRANSITION-METAL SURFACES SO PHYSICAL REVIEW LETTERS LA English DT Article ID PSEUDOPOTENTIAL THEORY; SOLID METALS; ENERGIES; MO(001); LEED AB The first-principles generalized pseudopotential theory of bulk transition-metal interatomic potentials is extended to surfaces by transforming the total-energy functional to a local-environment representation in which both the volume term and the multi-ion potentials are modulated by local averages of the electron density or the density of states. The theory encompasses and goes beyond simple embedded-atom schemes by including the angular forces necessary to treat the central bcc metals. Applications to the vacancy-formation and free-surface energetics of Cu and Mo are discussed. C1 SANDIA NATL LABS, LIVERMORE, CA 94550 USA. RP UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NR 20 TC 62 Z9 63 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 3036 EP 3039 DI 10.1103/PhysRevLett.66.3036 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100025 ER PT J AU BURK, B THOMSON, RE ZETTL, A CLARKE, J AF BURK, B THOMSON, RE ZETTL, A CLARKE, J TI CHARGE-DENSITY-WAVE DOMAINS IN 1T-TAS2 OBSERVED BY SATELLITE STRUCTURE IN SCANNING-TUNNELING-MICROSCOPY IMAGES SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSITION; TAS2 AB The domain structure in the nearly commensurate charge-density-wave phase of 1T-TaS2 has been experimentally determined. Fourier-transformed scanning-tunneling-microscopy images display fine satellite structure in excellent agreement with that predicted by the amplitude- and phase-domain model of Nakanishi and Shiba. Earlier analyses of scanning-tunneling- and atomic-force-microscopy images of 1T-TaS2 in the nearly commensurate phase are shown to be inadequate for the unambiguous identification and characterization of domain structure. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP BURK, B (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 13 TC 50 Z9 50 U1 2 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 JUN 10 PY 1991 VL 66 IS 23 BP 3040 EP 3043 DI 10.1103/PhysRevLett.66.3040 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100026 ER PT J AU CHAPLINE, G YAMAGISHI, K AF CHAPLINE, G YAMAGISHI, K TI 3-DIMENSIONAL GENERALIZATION OF ANYON SUPERCONDUCTIVITY SO PHYSICAL REVIEW LETTERS LA English DT Article ID FRACTIONAL STATISTICS; 2 DIMENSIONS; EQUIVALENCE; PARTICLES; STATES; MODEL AB A three-dimensional generalization of the wave function of Girvin el al. is constructed by taking the N --> infinity limit of a solution of the two-dimensional massless Dirac equation with an SU(N) gauge field. The resulting wave function is closely related to instanton solutions of the self-dual Einstein equations, and can be used to construct a multiparticle wave function with remarkable holonomy properties and a ground-state wave function with off-diagonal long-range order. RP CHAPLINE, G (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 26 TC 8 Z9 8 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 3064 EP 3066 DI 10.1103/PhysRevLett.66.3064 PG 3 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100032 ER PT J AU BARANOWSKI, JM LILIENTALWEBER, Z YAU, WF WEBER, ER AF BARANOWSKI, JM LILIENTALWEBER, Z YAU, WF WEBER, ER TI EVIDENCE FOR SUPERCONDUCTIVITY IN LOW-TEMPERATURE GROWN GAAS SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; BA-CU-O; MICROWAVE-ABSORPTION; OXIDES AB Magnetic-field-modulated microwave absorption and dc susceptibility measurements have detected evidence for superconductivity in As-rich GaAs layers grown by molecular-beam epitaxy at low temperatures (LT-GaAs). The transition temperature from the normal to the superconducting phase is 10 K. Electron microscopy of these layers found a new, As-rich layered structure in LT-GaAs that is most likely the origin of the superconductivity. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP BARANOWSKI, JM (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720, USA. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 25 TC 36 Z9 36 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 10 PY 1991 VL 66 IS 23 BP 3079 EP 3082 DI 10.1103/PhysRevLett.66.3079 PG 4 WC Physics, Multidisciplinary SC Physics GA FP871 UT WOS:A1991FP87100036 ER PT J AU WALLACE, DC AF WALLACE, DC TI ENTROPY OF LIQUID-METALS SO PROCEEDINGS OF THE ROYAL SOCIETY-MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Article ID MOLECULAR-DYNAMICS; THERMODYNAMIC PROPERTIES; SODIUM; FLUID AB An extensive analysis of the entropy is reported for 22 nearly free electron metals. The pair correlation entropy is computed from measured pair correlation functions, and the magnitude and temperature dependence of this entropy contribution shows approximately universal behaviour for most liquid metals. The higher order correlation entropy is zero for the simple metals, but is non-zero for several complex liquid metals, including Hg, Ga and Sn. The results are interpreted in terms of the motion of ions in a liquid, in which each ion is approximately trapped in the potential well of its neighbours, and where the presence of higher-order correlation entropy implies the existence of an n-ion interaction, for n greater-than-or-equal-to 3. RP WALLACE, DC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. NR 43 TC 40 Z9 40 U1 0 U2 8 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8444 J9 P R SOC-MATH PHYS SC JI P. Roy. Soc.-Math. Phys. Sci. PD JUN 8 PY 1991 VL 433 IS 1889 BP 615 EP 630 DI 10.1098/rspa.1991.0067 PG 16 GA FT569 UT WOS:A1991FT56900008 ER PT J AU WALLACE, DC AF WALLACE, DC TI MELTING OF ELEMENTS SO PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID INELASTIC NEUTRON-SCATTERING; DENSITY-FUNCTIONAL THEORY; LATTICE-DYNAMICS; LIQUIDS; TRANSITION; PRESSURE; ENTROPY; SODIUM; METALS; SOLIDS AB The aim is to identify and evaluate the most important factors that determine the melting temperature T(m) of the elements. Experimental data are analysed in terms of statistical mechanical theories of the energy and entropy of crystal and liquid phases. The elements are divided into two groups, according to their value of the entropy of fusion at constant density, DELTA-S: the normal elements have DELTA-S close to 0.79k per atom, and the anomalous elements have DELTA-S much larger. For the normal elements, a melting rule is constructed in terms of two factors, the lattice dynamics characteristic temperature for entropy, and the liquid correlation entropy. For the anomalous elements, the large DELTA-S is attributed to a change in electronic groundstate upon melting, and the melting rule depends also on the corresponding electronic energy change. The melting rules give T(m) to an accuracy of around 20%, and at this level, anharmonicity and crystal symmetry effects are negligible. Two conclusions regarding the relative motion of ions in crystal and liquid phases are: (a) liquid higher order correlations lower T(m) because they lead to a more ordered liquid, and (b) the loss of long-range order in melting corresponds to DELTA-S almost-equal-to 0.79k per atom for normal and anomalous elements alike. RP WALLACE, DC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 57 TC 50 Z9 51 U1 0 U2 7 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 JUN 8 PY 1991 VL 433 IS 1889 BP 631 EP 661 DI 10.1098/rspa.1991.0068 PG 31 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FT569 UT WOS:A1991FT56900009 ER PT J AU LOWENSTERN, JB MAHOOD, GA RIVERS, ML SUTTON, SR AF LOWENSTERN, JB MAHOOD, GA RIVERS, ML SUTTON, SR TI EVIDENCE FOR EXTREME PARTITIONING OF COPPER INTO A MAGMATIC VAPOR-PHASE SO SCIENCE LA English DT Article ID VOLCANO; ELEMENTS; FLUIDS; ROCKS AB The discovery of copper sulfides in carbon dioxide- and chlorine-bearing bubbles in phenocryst-hosted melt inclusions shows that copper resides in a vapor phase in some shallow magma chambers. Copper is several hundred times more concentrated in magmatic vapor than in coexisting pantellerite melt. The volatile behavior of copper should be considered when modeling the volcanogenic contribution of metals to the atmosphere and may be important in the formation of copper porphyry ore deposits. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP LOWENSTERN, JB (reprint author), STANFORD UNIV,DEPT GEOL,STANFORD,CA 94305, USA. OI Lowenstern, Jacob/0000-0003-0464-7779 NR 32 TC 110 Z9 130 U1 2 U2 15 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 7 PY 1991 VL 252 IS 5011 BP 1405 EP 1409 DI 10.1126/science.252.5011.1405 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FP868 UT WOS:A1991FP86800027 PM 17772911 ER PT J AU LI, DQ MARKS, TJ ZHANG, TG WONG, GK AF LI, DQ MARKS, TJ ZHANG, TG WONG, GK TI RATIONAL DESIGN, SYNTHESIS, AND CHARACTERIZATION OF CHROMOPHORIC SUPERMOLECULAR SELF-ASSEMBLED MULTILAYER THIN-FILMS HAVING VERY LARGE OPTICAL NONLINEARITIES SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID LANGMUIR-BLODGETT; HYDROXYL-GROUPS; ADSORBED FILMS; MONOLAYERS; SURFACES; SPECTROSCOPY; ADSORPTION; IR AB A method for preparing organized, highly aligned, multifunctional donor-acceptor covalently bonded self-assemblies on silica surfaces is described. Using the organosilane coupling reagent, I3Si(CH2)2C6H4CH2I (Cp), the high-beta chromophore, 4-[N,N-bis(3-hydroxypropyl)amino]styryl-4'-pyridine (Ch) can be easily linked to surfaces via quaternization. Additional chromophore layer can be built up in this manner using chlorosilane/polyvinylalcohol as an intervening structural layer. These multilayer structures have been characterized by FTIR-ATR, UV-vis spectroscopy, advancing contact angle, and second harmonic generation measurements. The studies of NLO properties reveal good structural uniformity and second order susceptibilities chi-zzz(2) as high as 6 x 10(-7) esu for a single CpCh monolayer and 2 x 10(-7) esu for multilayer superlattices (lambda = 1064 nm). C1 NORTHWESTERN UNIV,DEPT PHYS,EVANSTON,IL 60208. NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. NORTHWESTERN UNIV,MAT RES CTR,EVANSTON,IL 60208. RP LI, DQ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,INC-4,LOS ALAMOS,NM 87545, USA. NR 16 TC 3 Z9 3 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3157 EP 3162 DI 10.1016/0379-6779(91)91254-8 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400072 ER PT J AU MAZUMDAR, S GUO, DD DIXIT, SN AF MAZUMDAR, S GUO, DD DIXIT, SN TI EXCITONIC OPTICAL NONLINEARITY IN CONJUGATED POLYMERS AND AROMATIC MOLECULAR CHROMOPHORES - A THEORETICAL APPROACH SO SYNTHETIC METALS LA English DT Meeting Abstract C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP MAZUMDAR, S (reprint author), UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3189 EP 3189 DI 10.1016/0379-6779(91)91263-A PG 1 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400081 ER PT J AU CAMPBELL, DK GAMMEL, JT LOH, EY AF CAMPBELL, DK GAMMEL, JT LOH, EY TI THE EFFECTS OF ELECTRON-ELECTRON INTERACTIONS ON THE OPTICAL-PROPERTIES OF CONDUCTING POLYMERS SO SYNTHETIC METALS LA English DT Meeting Abstract C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. THINKING MACHINES CORP,CAMBRIDGE,MA 02142. RP CAMPBELL, DK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3451 EP 3451 DI 10.1016/0379-6779(91)91324-4 PG 1 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400142 ER PT J AU GAMMEL, JT CAMPBELL, DK MAZUMDAR, S DIXIT, SN LOH, EY AF GAMMEL, JT CAMPBELL, DK MAZUMDAR, S DIXIT, SN LOH, EY TI DETERMINATION OF INTERACTION PARAMETERS IN PEIERLS-HUBBARD MODELS DESCRIBING FINITE POLYENES AND POLYACETYLENE SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID TRANS-POLYACETYLENE; DIMERIZATION; CHAIN AB We study the extent to which finite polyenes and polyacetylene can be described by the extended Peierls-Hubbard Hamiltonian (ePHH) in an internally consistent manner. Using Lanczos exact diagonalization methods (LEDM) on small systems, coupled with a novel boundary condition (b.c.) averaging technique, we investigate the excited state spectra of these models for the finite oligomer analogs of trans-polyacetylene, (CH)x. We search for sets of parameters describing the electron-phonon (e-p) and electron-electron (e-e) interactions which are consistent with all available experimental data on these systems, including the optical gap and bandwidth, the 2(1) A(g) state, longitudinal optical phonon frequency omega-LO,2 triplet excitations, and the optical absorptions assigned to charged and neutral solitons and to polarons. We conclude that the e-p coupling is substantially weaker than that suggested by purely e-p models and that the e-e interaction parameters are in the intermediate coupling regime (U approximately 2.5t(o)), consistent with values deduced from the finite polyenes. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV BAYREUTH,INST PHYS,W-8580 BAYREUTH,GERMANY. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. THINKING MACHINES CORP,CAMBRIDGE,MA 02142. RP GAMMEL, JT (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 14 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3471 EP 3475 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400147 ER PT J AU SHI, J BRUINSMA, R BISHOP, AR AF SHI, J BRUINSMA, R BISHOP, AR TI THEORY OF VANADIUM DIOXIDE SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID PEIERLS AB A spin-Peierls theory is presented for vanadium dioxide (VO2) below the metal-insulator transition temperature using a Peierls-Hubbard model. We find that VO2 is in the intermediate-to-strong-coupling regime by performing an exact numerical diagonalization on a finite-size chain. We also find a spectrum of low-lying, magnetic excitations in the strong-coupling regime corresponding to topological defects analogous to those in the Su-Schrieffer-Heeger (SSH) model for polyacetylene [1]. These defects can be probed by multi-photon absorptions. For depoed VO2, there are in addition charged topological defects in the single-photon spectrum. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87544. RP SHI, J (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024, USA. NR 7 TC 1 Z9 1 U1 5 U2 6 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3527 EP 3530 DI 10.1016/0379-6779(91)91342-8 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400160 ER PT J AU SOMSKY, WR CAMPBELL, DK LIN, HQ WANG, X GUBERNATIS, JE AF SOMSKY, WR CAMPBELL, DK LIN, HQ WANG, X GUBERNATIS, JE TI QUANTUM MONTE-CARLO STUDY OF THE ONE-DIMENSIONAL EXTENDED HUBBARD HAMILTONIAN SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID SYSTEMS AB Using the worldline Monte Carlo method, implemented on both the vector-oriented CRAY X-MP and the massively parallel Connection Machine CM-2, we have been able to study the one-dimensional extended Hubbard model at very large lattice sizes and very low temperatures. This report presents a general overview of the methods involved and some results obtained thus far, including equilibrium energies and susceptibilities as functions of the filling ratio-rho and the extended Hubbard parameters U and V. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87544. RP SOMSKY, WR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87544, USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3531 EP 3534 DI 10.1016/0379-6779(91)91343-9 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400161 ER PT J AU WANG, X CAMPBELL, DK LIN, HQ VOGL, P AF WANG, X CAMPBELL, DK LIN, HQ VOGL, P TI A 3-DIMENSIONAL TIGHT-BINDING MODEL FOR TRANSPOLYACETYLENE SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON SCIENCE AND TECHNOLOGY OF SYNTHETIC METALS ( ICSM 90 ) CY SEP 02-07, 1990 CL TUBINGEN, FED REP GER ID INTRINSIC DEFECTS AB We develop a three-dimensional (3-D) generalization of the one-dimensional (1-D), tight-binding Su-Schrieffer-Heeger (SSH) model for trans-(CH)x. Importantly, the model faithfully reflects the 3-D character of the band-edge states as found in ab initio Local-Density-Approximation (LDA) calculations but remains simple enough to be analytically solvable for the dimerized ground state. We examine the density of states and the optical absorption predicted within this model, paying special attention to the roles of the transverse coupling and the polarization of the probing field. C1 TECH UNIV MUNICH,DEPT PHYS,W-8046 GARCHING,GERMANY. RP WANG, X (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. NR 5 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 7 PY 1991 VL 43 IS 1-2 BP 3567 EP 3570 DI 10.1016/0379-6779(91)91352-B PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA FV544 UT WOS:A1991FV54400170 ER PT J AU AMELIN, NS STAUBO, EF CSERNAI, LP TONEEV, VD GUDIMA, KK STROTTMAN, D AF AMELIN, NS STAUBO, EF CSERNAI, LP TONEEV, VD GUDIMA, KK STROTTMAN, D TI COLLECTIVITY, ENERGY DENSITY AND BARYON DENSITY IN PB ON PB COLLISIONS SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; CHARGED-PARTICLE SPECTRA; GLUON STRING MODEL; MULTIPLICITY DISTRIBUTIONS; MULTIPARTICLE PRODUCTION; NUCLEUS COLLISIONS; PBARP INTERACTIONS; 100-GEV/C; DYNAMICS; 12-GEV/C AB Predictions of string and hydrodynamical models for 160 A GeV Pb on Pb reactions are discussed, Results of the quark-gluon string model suggest that complete stopping of nuclear matter is plausible at these energies. The results for baryon and energy densities in the two models are similar. These results support the continued application of the one-fluid dynamic model, particularly for later stages of the collisions. C1 JOINT INST NUCL RES,THEORET PHYS LAB,DUBNA 101000,USSR. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP AMELIN, NS (reprint author), UNIV BERGEN,DEPT PHYS,ALLEGATEN 55,N-5007 BERGEN,NORWAY. NR 25 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JUN 6 PY 1991 VL 261 IS 4 BP 352 EP 356 DI 10.1016/0370-2693(91)90439-W PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA FT204 UT WOS:A1991FT20400002 ER PT J AU MILANEZ, S MURAL, RJ HARTMAN, FC AF MILANEZ, S MURAL, RJ HARTMAN, FC TI ROLES OF CYSTEINYL RESIDUES OF PHOSPHORIBULOKINASE AS EXAMINED BY SITE-DIRECTED MUTAGENESIS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID SPINACH PHOSPHORIBULOKINASE; RIBULOSE-5-PHOSPHATE KINASE; DNA; PROTEINS; NONESSENTIALITY; NITROCELLULOSE; ENZYMES; PEPTIDE; BINDING AB The Calvin Cycle enzyme phosphoribulokinase is activated in higher plants by the reversible reduction of a disulfide bond, which is located at the active site. To determine the possible contribution of the two regulatory residues (Cys16 and Cys55) to catalysis, site-directed mutagenesis has been used to replace each of them in the spinach enzyme with serine or alanine. The only other cysteinyl residues of the kinase, Cys244 and Cys250, were also replaced individually by serine or alanine. A comparison of specific activities of native and mutant enzymes reveals that substitutions at positions 244 or 250 are inconsequential. The position 16 mutants retain 45-90% of the wild-type activity and display normal K(m) values for both ATP and ribulose 5-phosphate. In contrast, substitution at position 55 results in 85-95% loss of wild-type activity, with less than a 2-fold increase in the K(m) for ATP and a 4-8-fold increase in the K(m) for ribulose 5-phosphate. These results are consistent with moderate facilitation of catalysis by Cys55 and demonstrate that the other three cysteinyl residues do not contribute significantly either to structure or catalysis. The enhanced stability, relative to wild-type enzyme, of the Ser16 mutant protein to a sulfhydryl reagent supports earlier suggestions that Cys16 is the initial target of the oxidative deactivation process. C1 UNIV TENNESSEE,GRAD SCH BIOMED SCI,OAK RIDGE,TN 37831. RP MILANEZ, S (reprint author), OAK RIDGE NATL LAB,DIV BIOL,PROT ENGN & MOLEC MUTAGENESIS PROGRAM,OAK RIDGE,TN 37831, USA. NR 31 TC 37 Z9 37 U1 0 U2 1 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUN 5 PY 1991 VL 266 IS 16 BP 10694 EP 10699 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FP086 UT WOS:A1991FP08600103 PM 1645355 ER PT J AU BRINKER, CJ FRYE, GC HURD, AJ ASHLEY, CS AF BRINKER, CJ FRYE, GC HURD, AJ ASHLEY, CS TI FUNDAMENTALS OF SOL-GEL DIP COATING SO THIN SOLID FILMS LA English DT Article AB During sol-gel thin film formation via dipping, polymeric or particulate inorganic precursors are concentrated on the substrate surface by a complex process involving gravitational draining with concurrent drying and continued condensation reactions. The structure of films deposited from polymeric precursors depends on such factors as size and structure of the precursors, relative rates of condensation and evaporation, capillary pressure, and substrate withdrawal speed. Using polymeric silicate precursors, the porosity and refractive index of the deposited films may be varied as follows: volume percent porosity (0%-56%); pore radius (0-3.1 nm); surface area (1.2-263 m2 g-1); refractive index (1.18-1.45). For repulsive, monosized particulate precursors, higher coating rates promote ordering of the particles as manifested by a reduction in porosity from 36% (random dense packing) to about 25% (f.c.c. or h.c.p.). RP SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. NR 20 TC 311 Z9 318 U1 11 U2 142 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUN 5 PY 1991 VL 201 IS 1 BP 97 EP 108 DI 10.1016/0040-6090(91)90158-T PG 12 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA FU716 UT WOS:A1991FU71600012 ER PT J AU COLLER, BS SPRINGER, KT MUTHUSAMY, M SCUDDER, LE NARLA, M BEER, J AF COLLER, BS SPRINGER, KT MUTHUSAMY, M SCUDDER, LE NARLA, M BEER, J TI FURTHER INVITRO CHARACTERIZATION OF THROMBOERYTHROCYTES (TE), A POTENTIAL AUTOLOGOUS, SEMIARTIFICIAL PLATELET SUBSTITUTE SO THROMBOSIS AND HAEMOSTASIS LA English DT Meeting Abstract C1 SUNY STONY BROOK,DIV HEMATOL,STONY BROOK,NY 11794. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 0 TC 2 Z9 2 U1 1 U2 1 PU F K SCHATTAUER VERLAG GMBH PI STUTTGART PA P O BOX 10 45 45, LENZHALDE 3, D-70040 STUTTGART, GERMANY SN 0340-6245 J9 THROMB HAEMOSTASIS JI Thromb. Haemost. PD JUN 5 PY 1991 VL 65 IS 6 BP 755 EP 755 PG 1 WC Hematology; Peripheral Vascular Disease SC Hematology; Cardiovascular System & Cardiology GA FZ966 UT WOS:A1991FZ96600311 ER PT J AU CHANG, CH ELKABBANI, O TIEDE, D NORRIS, J SCHIFFER, M AF CHANG, CH ELKABBANI, O TIEDE, D NORRIS, J SCHIFFER, M TI STRUCTURE OF THE MEMBRANE-BOUND PROTEIN PHOTOSYNTHETIC REACTION CENTER FROM RHODOBACTER-SPHAEROIDES SO BIOCHEMISTRY LA English DT Article ID ALPHA-HELIX DIPOLE; X-RAY-DIFFRACTION; RHODOPSEUDOMONAS-SPHAEROIDES; CHLOROFLEXUS-AURANTIACUS; L-SUBUNIT; MACROMOLECULAR STRUCTURES; 4-ALPHA-HELICAL PROTEINS; R-26; VIRIDIS; REFINEMENT AB The structure of the photosynthetic reaction center (RC) from Rhodobacter sphaeroides was determined at 3.1-angstrom resolution by the molecular replacement method, using the Rhodopseudomonas viridis RC as the search structure. Atomic coordinates were refined with the difference Fourier method and restrained least-squares refinement techniques to a current R factor of 22%. The tertiary structure of the RC complex is stabilized by hydrophobic interactions between the L and M chains, by interactions of the pigments with each other and with the L and M chains, by residues from the L and M chains that coordinate to the Fe2+, by salt bridges that are formed between the L and M chains and the H chain, and possibly by electrostatic forces between the ends of helices. The conserved residues at the N-termini of the L and M chains were identified as recognition sites for the H chain. C1 ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. FU NIGMS NIH HHS [GM36598] NR 35 TC 314 Z9 322 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 4 PY 1991 VL 30 IS 22 BP 5352 EP 5360 DI 10.1021/bi00236a005 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FP306 UT WOS:A1991FP30600005 PM 2036404 ER PT J AU ELKABBANI, O CHANG, CH TIEDE, D NORRIS, J SCHIFFER, M AF ELKABBANI, O CHANG, CH TIEDE, D NORRIS, J SCHIFFER, M TI COMPARISON OF REACTION CENTERS FROM RHODOBACTER-SPHAEROIDES AND RHODOPSEUDOMONAS-VIRIDIS - OVERALL ARCHITECTURE AND PROTEIN-PIGMENT INTERACTIONS SO BIOCHEMISTRY LA English DT Article ID PHOTOSYNTHETIC REACTION CENTER; AMINO-ACID SEQUENCE; X-RAY-DIFFRACTION; MACROMOLECULAR STRUCTURES; ELECTRON-TRANSFER; L-SUBUNIT; R-26; REFINEMENT; NUCLEOTIDE; BACTERIA AB Photosynthetic reaction centers (RCs) from the photosynthetic bacteria Rhodobacter sphaeroides and Rhodopseudomonas viridis are protein complexes closely related in both structure and function. The structure of the Rps. viridis RC was used to determine the structure of the RC from Rb. sphaeroides. Small but meaningful differences between the positions of the helices and the cofactors in the two complexes were identified. The distances between helices A(L) and A(M), between B(L) and B(M), and between bacteriopheophytins BP(L) and BP(M) are significantly shorter in Rps. viridis than they are in Rb. sphaeroides RCs. There are a number of differences in the amino acid residues that surround the cofactors; some of these residues form hydrogen bonds with the cofactors. Differences in chemical properties and location of these residues account in some manner for the different spectral properties of the two RCs. In several instances, the hydrogen bonds, as well as the apparent distances between the histidine ligands and the Mg atoms of the bacteriochlorophylls, were found to significantly differ from the Rb. sphaeroides RC structure previously described by Yeates et al. [(1988) Proc. Natl. Acad. Sci. U.S.A. 85, 7993-7997] and Allen et al. [(1988) Proc. Natl. Acad. Sci. U.S.A. 85, 8487-8491]. C1 ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. FU NIGMS NIH HHS [GM36598] NR 28 TC 243 Z9 248 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 4 PY 1991 VL 30 IS 22 BP 5361 EP 5369 DI 10.1021/bi00236a006 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FP306 UT WOS:A1991FP30600006 PM 2036405 ER PT J AU GEHRING, K WILLIAMS, PG PELTON, JG MORIMOTO, H WEMMER, DE AF GEHRING, K WILLIAMS, PG PELTON, JG MORIMOTO, H WEMMER, DE TI TRITIUM NMR-SPECTROSCOPY OF LIGAND-BINDING TO MALTOSE-BINDING PROTEIN SO BIOCHEMISTRY LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; ESCHERICHIA-COLI; SALMONELLA-TYPHIMURIUM; TERTIARY STRUCTURES; TRANSPORT; CONSTANTS; PRODUCT; GENE AB Tritium-labeled alpha- and beta-maltodextrins have been used to study their complexes with maltose-binding protein (MBP), a 40-kDa bacterial protein. Five substrates, from maltose to maltohexaose, were labeled at their reducing ends and their binding studied. Tritium NMR spectroscopy of the labeled sugars showed large upfield chemical shift changes upon binding and strong anomeric specificity. At 10-degrees-C, MBP bound alpha-maltose with 2.7 +/- 0.5-fold higher affinity than beta-maltose, and, for longer maltodextrins, the ratio of affinities (K(D)beta/K(D)alpha) was even larger (between 10 and 30). The maximum chemical shift change was 2.2 ppm, suggesting that the reducing end of bound alpha-maltodextrin makes close contact with an aromatic residue in the MBP-binding site. Experiments with maltotriose (and longer maltodextrins) also revealed the presence of two bound beta-maltotriose resonances in rapid exchange. We interpret these two resonances as arising from two distinct sugar-protein complexes. In one complex, the beta-maltodextrin is bound by its reducing end, and, in the other complex, the beta-maltodextrin is bound by the middle glucose residue(s). This interpretation also suggests how MBP is able to bind both linear and circular maltodextrins. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,NATL TRITIUM LABELING FACIL,BERKELEY,CA 94720. RI Gehring, Kalle/I-4403-2013 OI Gehring, Kalle/0000-0001-6500-1184 FU NCRR NIH HHS [P41RR01237] NR 50 TC 43 Z9 44 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 JUN 4 PY 1991 VL 30 IS 22 BP 5524 EP 5531 DI 10.1021/bi00236a027 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FP306 UT WOS:A1991FP30600027 PM 2036421 ER PT J AU MURRAY, PE AF MURRAY, PE TI RESIDUAL-STRESS AT FLUID INTERFACES WITH APPLICATION TO SILICON OXIDATION SO APPLIED PHYSICS LETTERS LA English DT Article ID FILM AB A fluid may undergo a constrained volume change as a result of the presence of a soluble chemical species. Corresponding to every constrained volume change is a residual stress. We present a method to include in the equations of fluid motion a body force to allow for the presence of residual stress. This method is used to calculate the residual stress associated with the chemical transformation of silicon to silicon dioxide in the presence of water vapor. RP MURRAY, PE (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 3 PY 1991 VL 58 IS 22 BP 2488 EP 2490 DI 10.1063/1.104852 PG 3 WC Physics, Applied SC Physics GA FP311 UT WOS:A1991FP31100011 ER PT J AU MARTENS, JS HIETALA, VM GINLEY, DS ZIPPERIAN, TE HOHENWARTER, GKG AF MARTENS, JS HIETALA, VM GINLEY, DS ZIPPERIAN, TE HOHENWARTER, GKG TI CONFOCAL RESONATORS FOR MEASURING THE SURFACE-RESISTANCE OF HIGH-TEMPERATURE SUPERCONDUCTING FILMS SO APPLIED PHYSICS LETTERS LA English DT Article AB A quasioptical technique of measuring superconductor surface resistance using a confocal resonator has been developed. The method has advantages of nondestructive analysis, high sensitivity, easy extension to higher frequencies, convenient experimental setup, and flexibility in sample size. Tl-Ca-Ba-Cu-O high-temperature superconducting films have been measured with this technique and the measured surface resistances were less than 0.01 OMEGA at 36.135 GHz and 77 K. The measurements have been performed from 29 to 39 GHz, and all films showed roughly a quadratic dependence of surface resistance with frequency. C1 UNIV WISCONSIN,DEPT ECE,MADISON,WI 53706. RP MARTENS, JS (reprint author), SANDIA NATL LABS,DEPT 1140,ALBUQUERQUE,NM 87185, USA. NR 13 TC 45 Z9 45 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 JUN 3 PY 1991 VL 58 IS 22 BP 2543 EP 2545 DI 10.1063/1.104821 PG 3 WC Physics, Applied SC Physics GA FP311 UT WOS:A1991FP31100030 ER PT J AU GRIFFIN, PA HERNANDEZ, OF AF GRIFFIN, PA HERNANDEZ, OF TI FEIGIN-FUCHS DERIVATION OF SU(1,1) PARAFERMION CHARACTERS SO NUCLEAR PHYSICS B LA English DT Article ID ALGEBRA; CONSTRUCTION AB We use the Feigin-Fuchs Coulomb gas construction, with two free gaussian bosons, to study the representation theory of the SU(1,1) parafermion models. We derive the chiral algebra and highest weights for unitary finitely reducible models, and calculate the irreducible parafermion characters which correspond to continuous and discrete unitary SU(1,1) representations. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. RP GRIFFIN, PA (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 20 TC 24 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD JUN 3 PY 1991 VL 356 IS 1 BP 287 EP 298 DI 10.1016/0550-3213(91)90150-V PG 12 WC Physics, Particles & Fields SC Physics GA FL652 UT WOS:A1991FL65200012 ER PT J AU LITTLEJOHN, RG FLYNN, WG AF LITTLEJOHN, RG FLYNN, WG TI GEOMETRIC PHASES AND THE BOHR-SOMMERFELD QUANTIZATION OF MULTICOMPONENT WAVE FIELDS SO PHYSICAL REVIEW LETTERS LA English DT Article ID CLASSICAL QUANTIZATION; PERIODIC-ORBITS; EQUATION; MECHANICS; MOTION; TERMS AB Geometric phases play an important role in the asymptotic behavior of multicomponent wave fields, such as electromagnetic waves in plasmas or quantum-mechanical spinors, particularly in the problem of Bohr-Sommerfeld quantization. The proper gauge independence of the eigenvalues and asymptotic wave functions can be understood in terms of gauge-invariant but noncanonical coordinates on the classical phase space. 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 25 TC 26 Z9 27 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 3 PY 1991 VL 66 IS 22 BP 2839 EP 2842 DI 10.1103/PhysRevLett.66.2839 PG 4 WC Physics, Multidisciplinary SC Physics GA FP085 UT WOS:A1991FP08500001 ER PT J AU DINNEEN, TP BERRAHMANSOUR, N BERRY, HG YOUNG, L PARDO, RC AF DINNEEN, TP BERRAHMANSOUR, N BERRY, HG YOUNG, L PARDO, RC TI PRECISION-MEASUREMENTS OF RELATIVISTIC AND QED EFFECTS IN HELIUM-LIKE BORON SO PHYSICAL REVIEW LETTERS LA English DT Article ID ISOELECTRONIC SEQUENCE; IONS AB We have made precision wavelength measurements on the 1s2s 3S1-1s2p 3P0.1.2-degrees transitions in helium-like boron using fast-beam laser excitation. These measurements are accurate to 2 parts in 10(7) of the transition energy and test the most recent calculations at a level of 0.1% of the Lamb shift. The relatively high Z of boron, in comparison to helium, makes the transition energies sensitive to higher powers of alpha-Z in the calculations, and our measurements show discrepancies which may be due to these uncalculated higher-order terms. C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. NR 21 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 3 PY 1991 VL 66 IS 22 BP 2859 EP 2862 DI 10.1103/PhysRevLett.66.2859 PG 4 WC Physics, Multidisciplinary SC Physics GA FP085 UT WOS:A1991FP08500006 ER PT J AU HEINEY, PA FISCHER, JE MCGHIE, AR ROMANOW, WJ DENENSTEIN, AM MCCAULEY, JP SMITH, AB COX, DE AF HEINEY, PA FISCHER, JE MCGHIE, AR ROMANOW, WJ DENENSTEIN, AM MCCAULEY, JP SMITH, AB COX, DE TI ORIENTATIONAL ORDERING TRANSITION IN SOLID C60 SO PHYSICAL REVIEW LETTERS LA English DT Article ID C-60; PHASE AB Synchrotron-x-ray powder-diffraction and differential-scanning-calorimetry measurements on solid C60 reveal a first-order phase transition from a low-temperature simple-cubic structure with a four-molecule basis to a face-centered-cubic structure at 249 K. The free-energy change at the transition is approximately 6.7 J/g. Model fits to the diffraction intensities are consistent with complete orientational disorder at room temperature, and with the development of orientational order rather than molecular displacements or distortions at low temperature. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. RP HEINEY, PA (reprint author), UNIV PENN,RES STRUCT MATTER LAB,PHILADELPHIA,PA 19104, USA. NR 14 TC 1270 Z9 1273 U1 10 U2 97 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 3 PY 1991 VL 66 IS 22 BP 2911 EP 2914 DI 10.1103/PhysRevLett.66.2911 PG 4 WC Physics, Multidisciplinary SC Physics GA FP085 UT WOS:A1991FP08500019 ER PT J AU RASOLT, M EDIS, T TESANOVIC, Z AF RASOLT, M EDIS, T TESANOVIC, Z TI KOSTERLITZ-THOULESS TRANSITION AND CHARGE REDISTRIBUTION IN THE SUPERCONDUCTIVITY OF YBCO/PBCO SUPERLATTICES SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTORS; TWO-DIMENSIONAL SUPERCONDUCTORS; YBA2CU3O7-X/PRBA2CU3O7-X SUPERLATTICES; BEHAVIOR AB Recent experimental measurements of the resistive transition in YBa2Cu3O7-x/PrBa2Cu3O7-x superlattices show a dramatic suppression in the resistive transition temperature T(c) as the thickness of the Pr layer increases while the thickness of the Y layer decreases. We show that the qualitative features of these experiments (and in particular most of the suppression in T(c)) can be accounted for within the Kosterlitz-Thouless theory. A small further suppression in T(c) is shown to occur due to charge transfer from Y to the Pr layers. C1 JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. UNIV CALIF LOS ALAMOS SCI LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. RP OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. NR 17 TC 72 Z9 72 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 3 PY 1991 VL 66 IS 22 BP 2927 EP 2930 DI 10.1103/PhysRevLett.66.2927 PG 4 WC Physics, Multidisciplinary SC Physics GA FP085 UT WOS:A1991FP08500023 ER PT J AU LORENZ, JC AF LORENZ, JC TI MAKING THE MOST OF THE GEOMETRIC RELATIONSHIPS BETWEEN DEVIATED WELL BORES AND REGIONAL NATURAL FRACTURES SO AAPG BULLETIN-AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS LA English DT Meeting Abstract C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER ASSN PETROL GEOLOGISTS PI TULSA PA 1444 S BOULDER AVE PO BOX 979, TULSA, OK 74101 SN 0149-1423 J9 AAPG BULL JI AAPG Bull.-Am. Assoc. Petr. Geol. PD JUN PY 1991 VL 75 IS 6 BP 1131 EP 1131 PG 1 WC Geosciences, Multidisciplinary SC Geology GA FQ258 UT WOS:A1991FQ25800049 ER PT J AU GAO, Q CLANCY, L WEBER, HP CRAVEN, BM MCMULLAN, RK AF GAO, Q CLANCY, L WEBER, HP CRAVEN, BM MCMULLAN, RK TI STRUCTURE OF THE ADIPATE COMPLEX [NA2(C6H9O4)2(C6H10O4)].2H2O FROM NEUTRON-DIFFRACTION AT 220 AND 295 K SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID HYDROGEN-BOND; 120-K AB The crystal structure of sodium hydrogen adipateadipic acid (2/1) dihydrate, [Na2(C6H9O4)2(C6H10O4)].2H2O, M(r) = 518.4, has been determined from neutron diffraction data collected at 220 and 295 K. Crystals are monoclinic, space group C2/m, with Z = 2. At 295 K, a = 9.378 (2), b = 13.379 (5), c = 10.247 (3) angstrom, beta = 95.93 (3)-degrees, V = 1278.8 (7) angstrom 3, D(n) = 1.346, D(m) = 1.348 (1) g cm-3 (in dibromomethane/bromobutane), lambda = 1.1588 (2) angstrom, mu = 2.186 cm-1, F(000) = 176.4 fm, R(F2) = 0.108 for all 1995 non-equivalent reflections with sin-theta/lambda < 0.71 angstrom -1. The crystal structure is similar at 220 K except for reduced nuclear mean-square displacements. Hydrogen adipate subunits (called A) are linked end-to-end in infinite chains by very short O...O (2.44 angstrom) hydrogen bonds where the H nuclei are on centers of symmetry within the experimental error. The Na cation is octahedrally coordinated by O atoms from molecules A and also by non-ionized adipic acid molecules (called B). The B molecules have large mean-square nuclear displacements which are described in terms of anharmonicity and disorder. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP GAO, Q (reprint author), UNIV PITTSBURGH,DEPT CRYSTALLOG,PITTSBURGH,PA 15260, USA. FU NHLBI NIH HHS [HL-20350] NR 24 TC 17 Z9 17 U1 0 U2 1 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 JUN 1 PY 1991 VL 47 BP 368 EP 375 DI 10.1107/S0108768190014021 PN 3 PG 8 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FR971 UT WOS:A1991FR97100009 PM 1910629 ER PT J AU KLOOSTER, WT RUBLE, JR CRAVEN, BM MCMULLAN, RK AF KLOOSTER, WT RUBLE, JR CRAVEN, BM MCMULLAN, RK TI STRUCTURE AND THERMAL VIBRATIONS OF ADENOSINE FROM NEUTRON-DIFFRACTION DATA AT 123 K SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article AB The crystal structure of adenosine, C10H13N5O4, M(r) = 267.24, has been refined by full-matrix least-squares methods using single-crystal neutron diffraction data (sin-theta/lambda < 0.79 angstrom -1) measured at 123 K. Crystal data at 123 K: monoclinic, P2(1), Z = 2, a = 4.7885 (8), b = 10.240 (2), c = 11.772 (2) angstrom, beta = 99.59 (2)-degrees, V = 569.2 angstrom 3, lambda = 1.0402 (1) angstrom, D(n) = 1.559 Mg m-3, mu = 191.1 m-1, F(000) = 175.72 fm, R(F2) = 0.044, wR(F2) = 0.055, S = 1.13 for 2450 reflections with F2 > 0.0. Bond lengths and angles have e.s.d.'s less than 0.002 angstrom and 0.1-degrees for non-H atoms and less than 0.004 angstrom and 0.3-degrees for H atoms. Values are in general agreement with those previously obtained from room-temperature X-ray data and with those obtained for 9-methyladenine by neutron diffraction at 126 K. Small displacements of amino H atoms from the least-squares plane through the non-H atoms of the adenine part appear to be the result of hydrogen bonding. There is an inter-molecular interaction C2-H2...O2' with an H...O distance of 2.20 angstrom. In its thermal vibrations, the adenosine molecule behaves as two rigid segments with a torsional libration about the glycosidic bond of 14.4 deg2 at 123 K. The force constant for this libration, as determined from the diffraction data, is 73 (10) J mol-1 deg-2. C1 UNIV PITTSBURGH,DEPT CRYSTALLOG,PITTSBURGH,PA 15260. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. FU NHLBI NIH HHS [HL-20350]; NIGMS NIH HHS [GM-22548] NR 26 TC 44 Z9 45 U1 0 U2 1 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 JUN 1 PY 1991 VL 47 BP 376 EP 383 DI 10.1107/S0108768190012903 PN 3 PG 8 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA FR971 UT WOS:A1991FR97100010 PM 1910630 ER PT J AU SPITZIG, WA AF SPITZIG, WA TI STRENGTHENING IN HEAVILY DEFORMATION PROCESSED CU-20-PERCENT NB SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID COMPOSITE WIRES; MICROSTRUCTURE AB Strengthening in heavily deformation processed Cu-20% Nb was compared with predictions from barrier and nonhomogeneous deformation models of hardening. A barrier model of strengthening, where the difficulty in propagating plastic flow across Cu-Nb interfaces controls strengthening, or a nonhomogeneous deformation model of strengthening in plastically deforming two phase structures, where the high density of dislocations generated to maintain compatibility between the Cu and Nb phases controls strengthening, were both in good agreement with the observed increases in strength with increasing deformation processing. Both models predict the observed Hall-Petch relation with Nb filament spacing. They also predict dislocation densities that continuously increase over the range of strains induced during deformation processing by wire drawing or rolling. This is in contrast to experimental observations indicating that the dislocation density in Cu-20% Nb is independent of the degree of deformation processing and that it is about the same as that measured in similarly deformation processed pure Cu. RP SPITZIG, WA (reprint author), IOWA STATE UNIV SCI & TECHNOL, US DOE, AMES LAB, DIV MET & CERAM, AMES, IA 50011 USA. NR 11 TC 83 Z9 101 U1 2 U2 6 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 JUN PY 1991 VL 39 IS 6 BP 1085 EP 1090 DI 10.1016/0956-7151(91)90195-7 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA FT192 UT WOS:A1991FT19200007 ER PT J AU SUKOL, JA AF SUKOL, JA TI THE COMPETITION IN CONTRACTING ACTS AUTOMATIC STAY PROVISION AND JUDICIAL-REVIEW - A TRAP FOR THE UNWARY SO ADMINISTRATIVE LAW REVIEW LA English DT Article RP SUKOL, JA (reprint author), US DOE,OFF ASSISTANT GEN COUNSEL PROCUREMENT & FINANCE,AMES,IA 50011, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER BAR ASSOC PI CHICAGO PA 750 N LAKE SHORE DR ATTN:ORDER FULFILLMENT, CHICAGO, IL 60611 SN 0001-8368 J9 ADMIN LAW REV JI Adm. Law Rev. PD SUM PY 1991 VL 43 IS 3 BP 439 EP 454 PG 16 WC Law SC Government & Law GA GB269 UT WOS:A1991GB26900004 ER PT J AU JACOBSON, S GOLSHANSHIRAZI, S GUIOCHON, G AF JACOBSON, S GOLSHANSHIRAZI, S GUIOCHON, G TI ISOTHERM SELECTION FOR BAND PROFILE SIMULATIONS IN PREPARATIVE CHROMATOGRAPHY SO AICHE JOURNAL LA English DT Article ID PROTEIN STATIONARY PHASES; NONLINEAR LIQUID-CHROMATOGRAPHY; BOVINE SERUM-ALBUMIN; OPTICAL RESOLUTION; MOBILE PHASE; IDEAL MODEL; AFFINITY-CHROMATOGRAPHY; NUMERICAL-SIMULATION; COMPUTER-SIMULATION; BINARY MIXTURE AB Equilibrium adsorption data for the N-benzoyl derivatives of D- and L-phenyl alanine in water/propanol solutions have been determined on a chiral-selective stationary bovine serum albumin immobilized on silica. These data are well accounted for by an isotherm equation resulting from the sum of two Langmuir terms. The first term corresponds to the chiral-selective interactions, and the second to the nonselective molecular interactions between the enantiomers and the stationary phase. The individual band profiles of the two enantiomeric amino acids, either pure or in binary mixtures of various compositions, are predicted exactly by an equilibrium dispersive model using this bi-Langmuir isotherm. A classical Langmuir isotherm fails to predict these band profiles, illustrating the importance to collect accurate adsorption data and to use a correct isotherm model when calculating chromatographic band profiles. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 47 TC 47 Z9 48 U1 1 U2 9 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 JUN PY 1991 VL 37 IS 6 BP 836 EP 844 DI 10.1002/aic.690370606 PG 9 WC Engineering, Chemical SC Engineering GA FR211 UT WOS:A1991FR21100004 ER PT J AU SINK, CH BERG, TA AF SINK, CH BERG, TA TI ADVANCED TECHNOLOGY FOR ENVIRONMENTAL RESTORATION NEEDS SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article C1 US DOE,OFF ENVIRONM RESTORAT & WASTE MANAGEMENT,WASHINGTON,DC 20585. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP SINK, CH (reprint author), US DOE,OFF TECHNOL DEV,WASHINGTON,DC 20585, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 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 JUN PY 1991 VL 70 IS 6 BP 1031 EP 1034 PG 4 WC Materials Science, Ceramics SC Materials Science GA FQ167 UT WOS:A1991FQ16700011 ER PT J AU WOOD, GO MOYER, ES AF WOOD, GO MOYER, ES TI A REVIEW AND COMPARISON OF ADSORPTION-ISOTHERM EQUATIONS USED TO CORRELATE AND PREDICT ORGANIC VAPOR CARTRIDGE CAPACITIES SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article ID KINETICS; MODEL AB Four adsorption isotherm equations for describing measured capacities of organic vapor air-purifying cartridges were compared. Experimental breakthrough curves were measured for five organic vapors: ethanol, carbon tetrachloride, acetone, chloroform, and hexane. Plots of service life at 1 % breakthrough versus bed weight (stacked cartridges) yielded capacities over concentration ranges for three brands of cartridges. The Freundlich, Langmuir, Dubinin/Radushkevich, and Hacskaylol LeVan isotherm equations fit the capacity versus vapor concentration data equally well, except in the case of ethanol. The ethanol fir was worse for the Freundlich equation. Other characteristics of these equations were related to their usefulness for correlating service life. C1 LOS ALAMOS NATL LAB,IND HYG GRP,LOS ALAMOS,NM 87544. NIOSH,DIV SAFETY RES,INJURY PREVENT RES BRANCH,LAB INVEST SECT,MORGANTOWN,WV 26505. NR 19 TC 18 Z9 18 U1 0 U2 4 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 JUN PY 1991 VL 52 IS 6 BP 235 EP 242 DI 10.1202/0002-8894(1991)052<0235:ARACOA>2.0.CO;2 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA KC587 UT WOS:A1991KC58700005 ER PT J AU KEHAYIAS, JJ HEYMSFIELD, SB LOMONTE, AF WANG, J PIERSON, RN AF KEHAYIAS, JJ HEYMSFIELD, SB LOMONTE, AF WANG, J PIERSON, RN TI INVIVO DETERMINATION OF BODY-FAT BY MEASURING TOTAL-BODY CARBON SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Article DE BODY COMPOSITION; FAT; TOTAL BODY CARBON; NEUTRON INELASTIC SCATTERING; NEUTRON ACTIVATION ID NEUTRON-ACTIVATION ANALYSIS; DUAL-PHOTON-ABSORPTIOMETRY; MASS; NITROGEN AB Total body carbon (TBC) is measured in vivo by neutron inelastic scattering. The fast neutrons needed for the irradiation are produced by a miniature deuterium-tritium (D-T) neutron generator. Body fat and protein are the main contributors to TBC. Bone ash and carbohydrates contribute < 3%. Fat is calculated from TBC after the subtraction of the carbon contributions from protein, bone, and glycogen. The technique was applied to 14 normal volunteers (8 females, 6 males) aged 24-94 y who underwent neutron inelastic scattering and neutron activation measurements for body carbon, nitrogen, and calcium. The initial results agree with other techniques. Unlike models that evaluate body fat by subtracting lean body mass from body weight, the TBC technique is not sensitive to assumptions on the composition of lean body; therefore, it is appropriate for studies of adults of any age and health condition. C1 COLUMBIA UNIV COLL PHYS & SURG,ST LUKES ROOSEVELT HOSP CTR,OBES RES CTR,DEPT MED,NEW YORK,NY 10032. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. COLUMBIA UNIV COLL PHYS & SURG,ST LUKES ROOSEVELT HOSP CTR,OBES RES CTR,DEPT RADIOL,NEW YORK,NY 10032. RP KEHAYIAS, JJ (reprint author), TUFTS UNIV,USDA,HUMAN NUTR RES CTR AGING,BODY COMPOSIT LAB,711 WASHINGTON ST,BOSTON,MA 02111, USA. FU NIDDK NIH HHS [DK26687, DK37352, DK41000-01] NR 24 TC 67 Z9 67 U1 0 U2 1 PU AMER SOC CLIN NUTRITION INC PI BETHESDA PA 9650 ROCKVILLE PIKE SUBSCRIPTIONS, RM L-2310, BETHESDA, MD 20814-3998 SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD JUN PY 1991 VL 53 IS 6 BP 1339 EP 1344 PG 6 WC Nutrition & Dietetics SC Nutrition & Dietetics GA FN399 UT WOS:A1991FN39900002 PM 2035460 ER PT J AU ALOIA, JF MCGOWAN, DM VASWANI, AN ROSS, P COHN, SH AF ALOIA, JF MCGOWAN, DM VASWANI, AN ROSS, P COHN, SH TI RELATIONSHIP OF MENOPAUSE TO SKELETAL AND MUSCLE MASS SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Article DE MENOPAUSE; BODY COMPOSITION; AGING; MUSCLE MASS; BONE MASS; BONE DENSITY; BODY CELL MASS; ADIPOSITY ID BONE-MINERAL DENSITY; TOTAL-BODY NITROGEN; NEUTRON-ACTIVATION; WOMEN; POTASSIUM; CALCIUM; AGE; STRENGTH; HABITUS; WEIGHT AB Cross-sectional and longitudinal changes in body composition with age were examined in white women to determine the relationship of body cell mass to menopause and of body fat to bone mass. There was statistical evidence for a curvilinear component to loss of total body potassium with negligible rates of loss before menopause. Longitudinal measurements also indicated a relationship between the proximity to menopause and the rate of loss of potassium. Total body potassium was significantly related to total body calcium and bone density of the spine, radius, and femoral neck. Total body fat was not related to any of these measurements. We found no evidence that adiposity plays a major role in protecting against bone loss. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. SUNY STONY BROOK,HLTH SCI CTR,STONY BROOK,NY 11794. RP ALOIA, JF (reprint author), WINTHROP UNIV HOSP,DEPT MED,259 1ST ST,MINEOLA,NY 11501, USA. FU NIAMS NIH HHS [AR37520-03] NR 24 TC 152 Z9 155 U1 1 U2 3 PU AMER SOC CLIN NUTRITION INC PI BETHESDA PA 9650 ROCKVILLE PIKE SUBSCRIPTIONS, RM L-2310, BETHESDA, MD 20814-3998 SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD JUN PY 1991 VL 53 IS 6 BP 1378 EP 1383 PG 6 WC Nutrition & Dietetics SC Nutrition & Dietetics GA FN399 UT WOS:A1991FN39900008 PM 2035465 ER PT J AU GODFREY, VL WILKINSON, JE RUSSELL, LB AF GODFREY, VL WILKINSON, JE RUSSELL, LB TI X-LINKED LYMPHORETICULAR DISEASE IN THE SCURFY (SF) MUTANT MOUSE SO AMERICAN JOURNAL OF PATHOLOGY LA English DT Article ID TUMOR NECROSIS FACTOR AB Scurfy (sf) is a spontaneous, sex-linked, recessive mutation that maps to the extreme proximal portion of the X chromosome, about 2 centimorgans from sparse fur (spf). Hemizygotes for sf manifest several clinical disorders, evident at 14 days of age, including scaliness and crusting of the eyelids, ears, and tail, runting, reddening and swelling of the genital papilla, anemia, cachexia, and early death (average, 24 days). Our studies indicate that the phenotype of hemizygous scurfy is not, as has been suggested, a model for human X-linked ichthyosis, but appears to be a disease primarily affecting the lymphoreticular, and possibly the hematopoietic, systems. Gross lesions include marked splenomegaly, hepatomegaly, enlarged lymph nodes, and variable thickening of the ears. The characteristic histologic lesion is a lymphohistiocytic proliferation and infiltration of peripheral lymph nodes, spleen, liver, and skin. In routine hematoxylin and eosin-stained sections, these lesions efface lymph node architecture, thicken the dermis, and form nodular portal infiltrates in the liver. Scurfy lesions characteristically contain a population of large blastlike cells with round to oval nuclei, a vesicular chromatin pattern, and prominent single nucleoli. Mixed perivascular infiltrates of lymphocytes, macrophages, and granulocytes sometimes are found in kidney, heart, pancreas, lung, and mesenteries. There is excessive hematopoiesis in the liver and spleen. Cells expressing B220 or Thy-1 antigens localize to appropriate areas in the lymph nodes and spleen, but are rare in the portal infiltrates and are absent from the skin. There is a marked, polyclonal increase in serum IgG, severe Coombs'-positive anemia, and leukocytosis with atypical mononuclear cells. Scurfy mice are negative for antinuclear antibodies. Despite their morphologically aberrant lymphoreticular system, scurfy mice can exist in a conventional environment without evidence of opportunistic infection. Raising scurfy mice in a specific-pathogen-free environment does not alter disease expression. Thus, while our findings indicate that scurfy disease may be the result of immune dysfunction, it is not a classic immunodeficiency. C1 UNIV TENNESSEE,COLL VET MED,KNOXVILLE,TN 37996. RP GODFREY, VL (reprint author), OAK RIDGE NATL LAB,DIV BIOL,POB 2009,OAK RIDGE,TN 37831, USA. NR 12 TC 195 Z9 204 U1 1 U2 7 PU AMER SOC INVESTIGATIVE PATHOLOGY, INC PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202-3993 SN 0002-9440 J9 AM J PATHOL JI Am. J. Pathol. PD JUN PY 1991 VL 138 IS 6 BP 1379 EP 1387 PG 9 WC Pathology SC Pathology GA FR746 UT WOS:A1991FR74600010 PM 2053595 ER PT J AU HODGE, EM PATTERSON, HP WILLIAMS, MC GLADNEY, ES AF HODGE, EM PATTERSON, HP WILLIAMS, MC GLADNEY, ES TI A COMPARATIVE-STUDY OF ELEMENTAL ANALYZERS FOR THE SIMULTANEOUS DETERMINATION OF C, H, AND N IN BIOLOGICAL-MATERIALS SO AMERICAN LABORATORY LA English DT Article AB Carbon, nitrogen, and hydrogen have been determined in 14 NIST biological standard reference materials by two independent combustion elemental analysis methods. The results are compared with the available literature values. RP HODGE, EM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,HLTH & ENVIRONM CHEM GRP HSE-9,MS K-484,LOS ALAMOS,NM 87544, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU INT SCIENTIFIC COMMUN INC PI SHELTON PA PO BOX 870, 30 CONTROLS DRIVE, SHELTON, CT 06484-0870 SN 0044-7749 J9 AM LAB JI Am. Lab. PD JUN PY 1991 VL 23 IS 9 BP 34 EP & PG 0 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA FQ340 UT WOS:A1991FQ34000007 ER PT J AU KWONG, MK ZETTL, A AF KWONG, MK ZETTL, A TI NORM INEQUALITIES FOR THE POWERS OF A MATRIX SO AMERICAN MATHEMATICAL MONTHLY LA English DT Note C1 NO ILLINOIS UNIV,DEPT MATH SCI,DE KALB,IL 60115. RP KWONG, MK (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU MATHEMATICAL ASSOC AMER PI WASHINGTON PA 1529 18TH STREET NW, WASHINGTON, DC 20036 SN 0002-9890 J9 AM MATH MON JI Am. Math. Mon. PD JUN-JUL PY 1991 VL 98 IS 6 BP 533 EP 538 DI 10.2307/2324875 PG 6 WC Mathematics SC Mathematics GA FR096 UT WOS:A1991FR09600008 ER PT J AU DOSE, EV GUIOCHON, GA AF DOSE, EV GUIOCHON, GA TI HIGH-RESOLUTION MODELING OF CAPILLARY ZONE ELECTROPHORESIS AND ISOTACHOPHORESIS SO ANALYTICAL CHEMISTRY LA English DT Article ID FUSED-SILICA CAPILLARIES; IONIC SPECIES INTERFACE; COMPUTER-SIMULATION; LIQUID-CHROMATOGRAPHY; NUMERICAL-SIMULATION; BAND PROFILES; SEPARATION; PERFORMANCE; BEHAVIOR; ELECTROOSMOSIS AB Detailed computer simulations of capillary zone electrophoresis (CZE) and isotachophoresis (ITP) experiments are presented. The mathematical model and its numerical implementation are described. New methods of managing time and space increments used in solving the differential equations are explained, and the advantages of segmenting the column length into active and inactive regions are outlined. The peak shapes obtained in linear CZE experiments match the shapes, areas, and widths expected from theory, and the numerical solutions are very stable. Simulation of a 6-min ITP experiment demonstrates the feasibility of simulating practical experiments with realistically low dispersion. Other simulation results stress the need for ITP electrolyte purity and illustrate the basis of currentless, flowless ("ubiquitous") injection. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 52 TC 89 Z9 89 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 1 PY 1991 VL 63 IS 11 BP 1063 EP 1072 DI 10.1021/ac00011a004 PG 10 WC Chemistry, Analytical SC Chemistry GA FN812 UT WOS:A1991FN81200006 ER PT J AU VANBERKEL, GJ MCLUCKEY, SA GLISH, GL AF VANBERKEL, GJ MCLUCKEY, SA GLISH, GL TI ELECTROSPRAY IONIZATION OF PORPHYRINS USING A QUADRUPOLE ION TRAP FOR MASS ANALYSIS SO ANALYTICAL CHEMISTRY LA English DT Article ID CAPILLARY ZONE ELECTROPHORESIS; CHEMICAL IONIZATION; SPECTROMETRY; INTERFACE; METALLOPORPHYRINS; GEOPORPHYRINS; CHLOROPHYLL; PLASMA; MATRIX AB The utility of electrospray (ES) ionization combined with ion trap mass spectrometry for the analysis of a wide variety of free-base porphyrins and metalloporphyrins is examined. A single molecular ionic species is observed in most cases for the porphyrins under study. The free bases are detected as the protonated molecules, (M + H)+, the trivalent metalloporphyrins as (M - L)+, where L- is a counteranion, and the divalent metalloporphyrins as M.+, (M + H)+, and/or (M + Na)+, depending upon both the metal complexed and the composition of the electrospray solvent. This marks the first reported observation of radical cations formed by ES ionization. Detection of the porphyrins studied by using continuous infusion required sampling as little as 1 fmol of material, while, with flow injection analysis, detection of 18 fmol of porphyrin is demonstrated. ES ionization is shown to be well suited for porphyrin molecular weight determination and for the analysis of porphyrin mixtures because no fragment ions are produced. Fragmentation of porphyrin ions via collision-induced dissociation (CID) and fragmentation induced by injection of ions into the trap are both shown to provide structure information. The degree of fragmentation upon injection can be varied via adjustment of ion injection parameters, either manually or automatically under computer control, providing a nonmass-selective means to induce fragmentation in the ion trap. The potential utility of automated control of ion injection parameters to provide both molecular weight and structure information when an on-line separation method is used with the ES/ion trap system is demonstrated. RP VANBERKEL, GJ (reprint author), OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831, USA. RI McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 66 TC 167 Z9 167 U1 4 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 1 PY 1991 VL 63 IS 11 BP 1098 EP 1109 DI 10.1021/ac00011a009 PG 12 WC Chemistry, Analytical SC Chemistry GA FN812 UT WOS:A1991FN81200011 ER PT J AU GOLSHANSHIRAZI, S HUANG, JX GUIOCHON, GA AF GOLSHANSHIRAZI, S HUANG, JX GUIOCHON, GA TI COMPARISON OF AN EXPERIMENTAL COMPETITIVE ISOTHERM AND THE LEVAN-VERMEULEN MODEL AND PREDICTION OF BAND PROFILES IN A CASE OF SELECTIVITY REVERSAL SO ANALYTICAL CHEMISTRY LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; NONLINEAR CHROMATOGRAPHY; ELUTION CHROMATOGRAPHY; ADSORPTION-ISOTHERMS; SEPARATION; DISPLACEMENT; EQUILIBRIUM; PROPAGATION; CAPACITIES; SIMULATION AB The second-order Levan-Vermeulen isotherm permits a correct account of the competitive isotherm data measured for the equilibrium of trans- and cis-androsterone between acetronitrile/dichloromethane solutions and a silica gel modified with a pH = 6.8 phosphate buffer. It is of special importance to report that the Levan-Vermeulen isotherm accounts well for the selectivity reversal observed at high concentrations. The cis isomer is more strongly retained at low concentrations, but its column saturation capacity is lower than for the trans isomer. The individual elution band profiles for large amounts of mixtures of trans- and cis-androsterone of relative concentrations 1/3, 1/1, and 3/1 are also accurately predicted. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 32 TC 27 Z9 27 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 1 PY 1991 VL 63 IS 11 BP 1147 EP 1154 DI 10.1021/ac00011a017 PG 8 WC Chemistry, Analytical SC Chemistry GA FN812 UT WOS:A1991FN81200019 ER PT J AU DOSE, EV GUIOCHON, GA AF DOSE, EV GUIOCHON, GA TI INTERNAL STANDARDIZATION TECHNIQUE FOR CAPILLARY ZONE ELECTROPHORESIS SO ANALYTICAL CHEMISTRY LA English DT Article ID MASS-SPECTROMETRIC DETECTION; CONDUCTIVITY DETECTION; SAMPLE INTRODUCTION; CHROMATOGRAPHY; ACID AB A new method of internal standardization for capillary zone electrophoresis (CZE) is founded on the linear relation between each ion's effective volume injected and its inherent mobility. The use of two internal standards allows the analyst to establish this relation quantitatively for each sample and to correct the analyte concentrations for variations in each injection. The computational method given is simple, and we demonstrate that it can give reproducibilities for manual CZE hydrodynamic and electrostatic injections of under 1% relative standard deviation. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 21 TC 121 Z9 122 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 1 PY 1991 VL 63 IS 11 BP 1154 EP 1158 DI 10.1021/ac00011a018 PG 5 WC Chemistry, Analytical SC Chemistry GA FN812 UT WOS:A1991FN81200020 ER PT J AU FUNG, KH TANG, IN AF FUNG, KH TANG, IN TI RELATIVE RAMAN-SCATTERING CROSS-SECTION MEASUREMENTS WITH SUSPENDED PARTICLES SO APPLIED SPECTROSCOPY LA English DT Article DE LIGHT SCATTERING; RAMAN SPECTROSCOPY; SPECTROSCOPIC TECHNIQUES ID SPECTROSCOPY AB An experimental technique using individual aerosol particles for relative Raman scattering cross-section measurement is described. An electrostatically charged particle of known chemical composition, 10 to 15-mu-m in diameter, is suspended in an electrodynamic cell. A single line (4880 angstrom) from an argon-ion laser is selected to induce the Raman scattering. The minute size and free rotation of the suspended particle ensure uniform sample illumination. The present results show very good linearity between the scattering intensity ratio and the molar mixing ratio. Sodium nitrate, ammonium nitrate, sodium sulfate, and ammonium sulfate are examined, and their respective Raman cross sections relative to that of sodium nitrate are determined to be 1, 0.9, 0.61, and 0.94. The uncertainty in this work is estimated to be less than 10%. RP FUNG, KH (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV ENVIRONM CHEM,UPTON,NY 11973, USA. NR 10 TC 29 Z9 29 U1 2 U2 7 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUN PY 1991 VL 45 IS 5 BP 734 EP 737 DI 10.1366/0003702914336679 PG 4 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA FV083 UT WOS:A1991FV08300004 ER PT J AU WANG, ZM WEEKS, SJ EDELSON, MC AF WANG, ZM WEEKS, SJ EDELSON, MC TI A HIGH-TEMPERATURE OVEN FOR LASER SPECTROSCOPY SO APPLIED SPECTROSCOPY LA English DT Article DE MODIFIED HEAT-PIPE OVEN; LASER ATOMIC ABSORPTION SPECTROSCOPY; THULIUM; HYPERFINE SPLITTING; ISOTOPE SHIFT ID ATOMIC-ABSORPTION SPECTROSCOPY AB A commercial heat-pipe oven (HPO) was modified to extend the useful temperature range from 700-degrees-C to approximately 1700-degrees-C. The utility of the modified heat pipe oven as an atom source for spectroscopy is demonstrated with a laser atomic absorption study of the hyperfine splitting of Tm (m.p. 1545-degrees-C). C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 25 TC 3 Z9 3 U1 1 U2 3 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUN PY 1991 VL 45 IS 5 BP 738 EP 742 DI 10.1366/0003702914336525 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA FV083 UT WOS:A1991FV08300005 ER PT J AU HAHN, JH SOPER, SA NUTTER, HL MARTIN, JC JETT, JH KELLER, RA AF HAHN, JH SOPER, SA NUTTER, HL MARTIN, JC JETT, JH KELLER, RA TI LASER-INDUCED FLUORESCENCE DETECTION OF RHODAMINE-6G AT 6 X 10-15 M SO APPLIED SPECTROSCOPY LA English DT Article DE FLUORESCENCE; LASER; HIGH SENSITIVITY ID HYDRODYNAMICALLY FOCUSED FLOWS; SINGLE MOLECULES; PHYCOERYTHRIN; FLUOROMETER; CUVETTE; SAMPLES; IONS AB We have demonstrated sensitive fluorescence detection of rhodamine-6G in aqueous solutions down to approximately 10(-15) M with a detection limit of 6 x 10(-15) M. The working curve was observed to be linear over four orders of magnitude and could be extended to higher concentrations. Single molecules of rhodamine-6G had a transit time of 1.8 ms through the 11 pL probe volume. At 2 x 10(-14) M, the probability of a molecule being in the 11 pL probe volume is approximately 0.1. Analysis of the data indicates that the signal-to-noise for the detection of a single molecule of rhodamine-6G is approximately 1. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. NR 23 TC 14 Z9 14 U1 0 U2 3 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUN PY 1991 VL 45 IS 5 BP 743 EP 746 DI 10.1366/0003702914336453 PG 4 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA FV083 UT WOS:A1991FV08300006 ER PT J AU CAREY, WP JORGENSEN, BS AF CAREY, WP JORGENSEN, BS TI OPTICAL SENSORS FOR HIGH ACIDITIES BASED ON FLUORESCENT POLYMERS SO APPLIED SPECTROSCOPY LA English DT Article DE ACID SENSOR; POLYMER FLUORESCENCE; FIBEROPTIC CHEMICAL SENSOR ID POLYQUINOLINES AB An indirect method for monitoring acid concentrations from 0.1 to 10 M was developed on the basis of the fluorescence of linear-chain, rigidrod polymers. These linear polymers have high strength and acid-resistant properties that are ideal for support materials, as well as having chemical functionalities that can be protonated under highly acidic conditions to provide a sensing mechanism. By immobilization of the polymers on the endface of an optical fiber, an acidity sensor for monitoring nitric and hydrochloric acids was developed with the use of the change in fluorescent emission as a function of acid concentration. Polymers tested for sensor applications include poly(phenylquinoline), poly(biphenylquinoline), and poly(phenylquinoxaline). The quinoxaline responded from 0.1 to 2 M nitric acid, and the quinolines responded from 2 to 10 M nitric acid. The performance of sensors developed with these materials resulted in a relative standard deviation of approximately 10%. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL MST-7 MS E549,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV NUCL MAT TECHNOL NMT-2 MS E501,LOS ALAMOS,NM 87545. NR 10 TC 21 Z9 22 U1 0 U2 0 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUN PY 1991 VL 45 IS 5 BP 834 EP 838 DI 10.1366/0003702914336688 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA FV083 UT WOS:A1991FV08300018 ER PT J AU KHAN, SUM BALTRUS, JP LAI, RW RICHARDSON, AG AF KHAN, SUM BALTRUS, JP LAI, RW RICHARDSON, AG TI X-RAY PHOTOELECTRON SPECTROSCOPIC STUDY OF THE INTERACTION OF XANTHATE WITH COAL PYRITE AND MINERAL PYRITE SURFACES SO APPLIED SURFACE SCIENCE LA English DT Article ID ADSORPTION; FLOTATION; XPS; GALENA AB Coal pyrite and mineral pyrite surfaces were examined by X-ray photoelectron spectroscopy (XPS) before and after treatment in acidic and basic solutions of sodium ethyl xanthate (NaEtX). XPS showed that the degree of oxidation of coal and mineral pyrite surfaces increased when these pyrites were conditioned in basic solutions. However, conditioning in acidic solutions led to partial removal of surface oxidation from the pyrites. Addition of NaEtX to the acidic and basic solutions enhanced the removal of oxidation from pyrite surfaces. Pretreatment with sulfur dioxide further enhanced the removal of surface oxidation in the presence of NaEtX. Surface oxidation was typically less on mineral pyrite than coal pyrite surfaces following identical treatments. The flotation recoveries of the pyrites in the presence of NaEtX are greatest for the pyrites with the least amount of surface oxidation. C1 US DOE,PITTSBURGH ENERGY TECHNOL CTR,PITTSBURGH,PA 15236. RP KHAN, SUM (reprint author), DUQUESNE UNIV,DEPT CHEM,PITTSBURGH,PA 15282, USA. NR 21 TC 10 Z9 10 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JUN PY 1991 VL 47 IS 4 BP 355 EP 363 DI 10.1016/0169-4332(91)90088-2 PG 9 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA FR369 UT WOS:A1991FR36900006 ER PT J AU BRODRICK, JR LEWIS, JE AF BRODRICK, JR LEWIS, JE TI PLANNING FOR THE RESIDENTIAL REPLACEMENT MARKET IN THE 1990S SO ASHRAE JOURNAL-AMERICAN SOCIETY OF HEATING REFRIGERATING AND AIR-CONDITIONING ENGINEERS LA English DT Article RP BRODRICK, JR (reprint author), PACIFIC NW LAB, CTR TECHNOL PLANNING & ANAL, RICHLAND, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC HEAT REFRIG AIR- CONDITIONING ENG INC PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 SN 0001-2491 J9 ASHRAE J JI ASHRAE J.-Am. Soc. Heat Refrig. Air-Cond. Eng. PD JUN PY 1991 VL 33 IS 6 BP 43 EP + PG 0 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA FR497 UT WOS:A1991FR49700012 ER PT J AU DICKEL, JR VANBREUGEL, WJM STROM, RG AF DICKEL, JR VANBREUGEL, WJM STROM, RG TI RADIO STRUCTURE OF THE REMNANT OF TYCHO SUPERNOVA (SN 1572) SO ASTRONOMICAL JOURNAL LA English DT Article ID NOVA REMNANT; X-RAY; ALGORITHM; EVOLUTION AB The radio emission from the remnant of Tycho's supernova of 1572 arises in a nearly circular, clumpy shell. A very distinct, thin bright rim just outside the main shell can be seen around most of the periphery of the remnant. The outer edge of radio emission, usually defined by this bright rim, coincides perfectly with the outer x-ray boundary. Most of the emission is polarized by a modest amount, with the outer rim particularly prominent. We have used our observations at several wavelengths to map out the rotation measure at high angular resolution, and determine the intrinsic magnetic field direction. The magnetic field shows a somewhat cellular pattern but with a net radial orientation and a generally fairly low degree of polarization. There is no evidence for internal Faraday rotation or depolarization of the observed polarized emission from the remnant. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. NETHERLANDS FDN RES ASTRON,7990 AA DWINGELOO,NETHERLANDS. RP DICKEL, JR (reprint author), UNIV ILLINOIS,DEPT ASTRON,1002 W GREEN ST,URBANA,IL 61801, USA. NR 44 TC 84 Z9 85 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1991 VL 101 IS 6 BP 2151 EP & DI 10.1086/115837 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FN636 UT WOS:A1991FN63600018 ER PT J AU WEBER, F GLENDENNING, NK WEIGEL, MK AF WEBER, F GLENDENNING, NK WEIGEL, MK TI STRUCTURE AND STABILITY OF ROTATING RELATIVISTIC NEUTRON-STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE EQUATION OF STATE; RELATIVITY; STARS; INTERIORS; STARS; NEUTRON; STARS; ROTATION ID MILLISECOND PULSAR; NUCLEAR-MATTER; LAMBDA-APPROXIMATIONS; GROUND-STATE; EQUATION; MODELS; INSTABILITY; FREQUENCY; COLD; HOT AB The aim of this work is twofold: (1) We investigate the influence of rotation on the bulk properties of neutron stars. (2) The limiting angular velocities at which instability against gravitational radiation-reaction sets in are calculated for rotating neutron stars of gravitational masses M = 1.5 M. and M = 1.9 M. The calculations are based on four different, realistic neutron matter equations of state derived in the framework of relativistic nuclear field theory. Two of them are calculated in the relativistic Hartree and Hartree-Fock approximation for electrically charge neutral many-baryon matter at zero temperature. The influence of two-particle correlations on the bulk properties of both rotating and nonrotating neutron stars is demonstrated through neutron matter equations of state calculated for the relativistic ladder approximation to the two-particle scattering matrix in matter by using the Holinde-Erkelenz-Alzetta (HEA) and Machleidt-Holinde-Elster (Bonn) meson-exchange potentials. We obtain from these two equations of state maximum rotating star models having Keplerian frequencies of 1.19 x 10(3) s-1 (HEA) and 9.8 x 10(3) s-1 (Bonn) and gravitational masses of 2.51 and 2.25 M., respectively. However, from the study of the onset of instability modes caused by gravitational radiation and moderated by (shear) viscosity, performed for all four models and at two masses of 1.5 and 1.9 M., it follows that an m = 4 and/or m = 5 instability mode is probably responsible for limiting the angular velocity of rotating, hot neutron stars (and not the Keplerian frequency). To be more specific, we find that these instability modes are excited at frequencies of 60%-65% (depending on the equation of state as well as on the mass of the star) of the Keplerian value. The limiting frequency of an old neutron star being spun up and reheated up to temperature T almost-equal-to 10(7) K by mass accretion is set by the m = 3 mode. The related instability frequencies are 77%-92% and 80%-91% of the Keplerian value for the M = 1.5 M. and M = 1.9 M. star models, respectively. For T congruent-to 10(6) K the m = 2 mode is excited first; however, since its value is of comparable size with the Keplerian frequency, mass shedding can be expected to set the limit on stable neutron star rotation in this case. These findings have important implications for the possible future discovery of fast pulsars. C1 UNIV MUNICH,INST THEORET PHYS,W-8000 MUNICH 2,GERMANY. UNIV MUNICH,SEKT PHYS,W-8046 GARCHING,GERMANY. RP WEBER, F (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 60 TC 51 Z9 52 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 JUN 1 PY 1991 VL 373 IS 2 BP 579 EP 591 DI 10.1086/170077 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FM779 UT WOS:A1991FM77900024 ER PT J AU LINK, BK EPSTEIN, RI AF LINK, BK EPSTEIN, RI TI MECHANICS AND ENERGETICS OF VORTEX UNPINNING IN NEUTRON-STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE DENSE MATTER; HYDRODYNAMICS; PULSARS; STARS; NEUTRON ID INTERNAL TEMPERATURE; ROTATING SUPERFLUIDS; HYDRODYNAMICS; CREEP AB A rotating neutron superfluid is threaded by quantized vortex lines which, in the inner crust of a neutron star, can pin to the nuclear lattice that coexists with the superfluid. In the nuclear pinning region of the stellar crust (stellar densities greater-than-or-similar-to 10(13) g cm-3) the lines pin to nuclei, while in the interstitial pinning region (densities less-than-or-similar-to 10(13) g cm-3) the lines pin between nuclei. Some of the peculiar timing features of pulsars may be due to the unpinning and movement of these vortex lines. The nature of vortex unpinning is determined by the relative importance of tension in the vortex line and the pinning forces acting upon it. If the vortex is relatively flexible, only one or a few bonds break simultaneously, whereas if it is relatively stiff, many pinning bonds break. For the pinning parameters of Epstein and Baym, we find that in the nuclear pinning region the vortex line is comparatively flexible, while for the interstitial pinning regions the vortex is stiff. For nuclear pinning energies weaker than those considered here, tension would be relatively more significant. In the interstitial pinning region, pinning energies are the order of 1 keV per site, and vortices can remain pinned for velocity differences upsilon-delta between the superfluid and the crust of upsilon-B approximately 10(5) cm s-1. For 3-upsilon-B/4 less-than-or-equal-to upsilon-delta < upsilon-B, pinned vortices may unpin by overcoming an energy activation barrier whose height varies as (1 - upsilon-delta/upsilon-B)3/2j* where j* is the characteristic number of pinning bonds involved in the unpinning event. As upsilon-delta becomes small, the activation energy diverges as upsilon-B/upsilon-delta. C1 UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801. RP LINK, BK (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 19 TC 35 Z9 35 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 JUN 1 PY 1991 VL 373 IS 2 BP 592 EP 603 DI 10.1086/170078 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FM779 UT WOS:A1991FM77900025 ER PT J AU MAUCHE, CW AF MAUCHE, CW TI HIGH-RESOLUTION IUE SPECTRA OF THE NOVA-LIKE VARIABLE IX-VELORUM SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS; BINARIES; STARS; DWARF NOVAE; STARS; INDIVIDUAL (IX-VELORUM); ULTRAVIOLET; SPECTRA ID CATACLYSMIC VARIABLES; CPD -48-DEGREES-1577; CPD-48-DEGREES-1577; EMISSION; MAJORIS; WINDS; LINES AB High-resolution ultraviolet spectra of the nova-like variable IX Vel obtained with the International Ultraviolet Explorer satellite are used in two separate but related studies of the wind of this bright cataclysmic variable. In the first, we studied the velocity offsets of the P Cygni profile of Si IV, which manifests itself as a pair of broad blueshifted absorption features. Upon phasing the velocity offsets of these features on the orbital period, it is found that they vary sinusoidally with an amplitude and phase which are to first order consistent with an origin on the white dwarf and/or accretion disk. If the source of the wind is indeed centered on the white dwarf, the velocity of the wind responsible for the broad Si IV absorption features is V(wind) (phi) approximately -400 + 100 cos (2-pi-phi) km s-1, where phi is the azimuthal angle between the white dwarf and secondary. The velocity of the wind is therefore lowest on the side facing the secondary and highest on the side facing away from the secondary. The mean velocity of approximately 400 km s-1 is significantly lower than the approximately 2000-3000 km s-1 terminal velocity of the wind determined from the blue wing of the absorption component of the P Cygni profile of C IV. This fact, combined with the absence of any significant emission component to the P Cygni profile of Si IV, argues that the component of the wind in which Si IV dominates lies at a lower velocity and originates in a smaller volume than the component of the wind in which C IV dominates. In the second study we searched for narrow, possibly transient, spectral features in the P Cygni profiles of Si IV and C IV and discovered a number of significant features which may be analogous to the "discrete absorption components" observed in the P Cygni profiles of early-type stars. We briefly consider the origin of these features and compare their properties with those of early-type stars. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550. RP MAUCHE, CW (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SPACE ASTRON & ASTROPHYS GRP,LOS ALAMOS,NM 87544, USA. NR 24 TC 19 Z9 19 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 JUN 1 PY 1991 VL 373 IS 2 BP 624 EP 632 DI 10.1086/170082 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FM779 UT WOS:A1991FM77900029 ER PT J AU SCHACHTER, J FILIPPENKO, AV KAHN, SM PAERELS, FBS AF SCHACHTER, J FILIPPENKO, AV KAHN, SM PAERELS, FBS TI BOWEN FLUORESCENCE IN AM HERCULIS STARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; RADIATIVE TRANSFER; STARS; BINARIES; STARS; EMISSION-LINE; STARS; INDIVIDUAL (AM HERCULIS; EF ERIDANI); ULTRAVIOLET; SPECTRA ID ULTRAVIOLET OBSERVATIONS; EMISSION-LINES; SCORPIUS X-1; HE-II; O-III; RAY; SPECTROPHOTOMETRY; MECHANISM; RADIATION; STRENGTHS AB We relate new observations of Bowen fluorescence lines in AM Her and EF Eri, two AM Her systems. These objects display a rich array of Bowen lines, including O III lambda-lambda-3123, 3133, 3299, 3312, 3341, 3407, 3429, 3444 and N III lambda-lambda-4634, 4641, 4642. There is unambiguous evidence for the O3 process in the cascades of O III. We also see strong emission lines of H I, He I, and He II, together with a few detections of Ca II and C II. Many of these lines show a complex multiple-component structure, which differs significantly from that observed by previous investigators. The intensity ratios of H I, He I, and He II emission line series depart from those expected in case B recombination. For our H I and He II observations of AM Her and EF Eri, the line ratios are much flatter than case B, suggesting substantial line opacities. We use a simple thin slab model to calculate constraints on the expected optical depths and electron temperatures in the H I zone and (for AM Her) in the He II zone. In AM Her, allowed opacity and temperature values are strongly correlated. However, in this object we invariably find T greater-than-or-similar-to 7000 K and tau-H-alpha greater-than-or-similar-to 100 in the H I zone, whereas T greater-than-or-similar-to 20,000 K and tau-1640 less-than-or-similar-to 200 in the He II zone. The analysis yields tau-H-alpha almost-equal-to 200 for EF Eri. By making the assumption that the He II level populations approach LTE, we can use the observed Bowen line intensities to estimate the size (R), density, and temperature of the emission region. We find R almost-equal-to 10(8) - 10(9) cm, n(e) almost-equal-to 10(11) - 10(18) cm-3, and T(e) almost-equal-to 20,000-30,000 K. The derived values of R are significantly less than the size of the Roche lobe of the white dwarf [approximately(2-5) x 10(10) cm]; hence, we may be probing a length scale in the accretion column. The large range of densities reflects the exponential temperature dependence in our expression for n(e), so that better temperature estimates from future observations will produce tighter n(e) constraints. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY SCI,LIVERMORE,CA 94550. NR 47 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1991 VL 373 IS 2 BP 633 EP 648 DI 10.1086/170083 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FM779 UT WOS:A1991FM77900030 ER PT J AU CANNON, TM KOSKELA, RJ BURKS, C STALLINGS, RL FORD, AA HEMPFNER, PE BROWN, HT FICKETT, JW AF CANNON, TM KOSKELA, RJ BURKS, C STALLINGS, RL FORD, AA HEMPFNER, PE BROWN, HT FICKETT, JW TI A PROGRAM FOR COMPUTER-ASSISTED SCORING OF SOUTHERN BLOTS SO BIOTECHNIQUES LA English DT Article ID GEL-ELECTROPHORESIS; DNA AB SCORE, a program for computer-assisted scoring of Southern blots of clone DNA, retains the use of expert human judgment while taking over much of the drudgery of the scoring task. The primary functions of the program are to help make an aligned overlay of the fluorescence gel image and the autoradiogram blot image, to keep track of band and lane locations and to store the resulting data directly into a database. Use of SCORE has resulted in greatly increased efficiency and accuracy. C1 UNIV CALIF LOS ALAMOS SCI LAB,T-10 MS K710,LOS ALAMOS,NM 87545. RI Stallings, Raymond/A-7213-2008 NR 11 TC 3 Z9 3 U1 0 U2 0 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD JUN PY 1991 VL 10 IS 6 BP 764 EP 767 PG 4 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FQ809 UT WOS:A1991FQ80900015 PM 1878210 ER PT J AU GORDON, JE FISHER, RA KIM, S PHILLIPS, NE AF GORDON, JE FISHER, RA KIM, S PHILLIPS, NE TI THERMAL AND MAGNETIC MEASUREMENTS ON YBA2CU3O7-Y SO BULLETIN OF MATERIALS SCIENCE LA English DT Article DE SPECIFIC HEAT; MAGNETIC SUSCEPTIBILITY; YBA2CU3O7-Y AB Specific heat measurements in zero and 7T magnetic fields from 0.4 to 100 K, and magnetic susceptibility measurements above T(c) on a series of polycrystalline samples of YBa2Cu3O7-y (YBCO) reveal a number of regularities. The size of DELTA-C(T(c))/T(c) for the samples [DELTA-C(T(c)) is the jump in the specific heat at T(c)] appears to vary linearly with the low-temperature value of the Debye THETA, with the entropy change between almost-equal-to 85 K and T(c) induced by the application of a 7T magnetic field, and with the variation of the observed low temperature gamma with magnetic field, d-gamma/dH. On the other hand the temperature-independent part of the magnetic susceptibility above T(c) appears to be essentially independent of DELTA-C(T(c))/T(c). These results are consistent with the idea that samples of YBCO below T(c) are a mixture of superconducting and normal phases. RP GORDON, JE (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU INDIAN ACADEMY SCIENCES PI BANGALORE PA P B 8005 C V RAMAN AVENUE, BANGALORE 560 080, INDIA SN 0250-4707 J9 B MATER SCI JI Bull. Mat. Sci. PD JUN PY 1991 VL 14 IS 3 BP 651 EP 654 DI 10.1007/BF02744700 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA GB278 UT WOS:A1991GB27800021 ER PT J AU JARPE, S DOWLA, F AF JARPE, S DOWLA, F TI PERFORMANCE OF HIGH-FREQUENCY 3-COMPONENT STATIONS FOR AZIMUTH ESTIMATION FROM REGIONAL SEISMIC PHASES SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SINGLE; LOCATION; EVENTS; ARRAYS AB We assessed the performance of high-frequency three-component stations for estimating bearing of regional phases using P waves from 18 mining explosions at a single construction site in Norway. We studied errors in bearing estimates as a function of the parameters frequency, frequency bandwidth, SNR, and analysis window length using seismic signals recorded on a three-component high-frequency (> 50 Hz) seismic element (HFSE) located at the NORESS array in Norway. We found that the time-bandwidth product (TB) and SNR are the most important factors in reducing the bearing estimation error. Bearing errors were minimized for SNR greater-than-or-equal-to a factor of 5, and TB greater-than-or-equal-to 100. We also found that three-component signals contain bearing information at frequencies as high as 45 Hz when there is sufficient SNR in the signal. Bearing estimation performance can be significantly improved by the appropriate selection of signal parameters, - such as window length and frequency. Since these parameters are usually unknown, we propose a parameter variation technique that extracts the best answer by first determining the bearing distribution as a function of the above parameters. The results of this study indicate that with a single three-component station and for high (greater-than-or-equal-to 5) SNR, the parameter variation method can determine the bearings of events to within a standard deviation of 6-degrees, which is similar to the uncertainty in NORESS array bearing estimates for the same events. RP JARPE, S (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,L-205,LIVERMORE,CA 94550, USA. NR 18 TC 8 Z9 8 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 JUN PY 1991 VL 81 IS 3 BP 987 EP 999 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FR329 UT WOS:A1991FR32900015 ER PT J AU JOHNSON, DW VANMIEGROET, H LINDBERG, SE TODD, DE HARRISON, RB AF JOHNSON, DW VANMIEGROET, H LINDBERG, SE TODD, DE HARRISON, RB TI NUTRIENT CYCLING IN RED SPRUCE FORESTS OF THE GREAT SMOKY MOUNTAINS SO CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE LA English DT Article ID DRY DEPOSITION VELOCITIES; EASTERN NORTH-AMERICA; AIR-POLLUTION; ATMOSPHERIC DEPOSITION; HIGH ELEVATION; CANOPY THROUGHFALL; DECIDUOUS FOREST; ABIES-AMABILIS; LOBLOLLY-PINE; TREE RINGS AB Nutrient distributions, concentrations, and fluxes in two red spruce (Picea rubens Sarg.) stands in the Great Smoky Mountains are described and used to evaluate various hypotheses for recent decline of this species. These forests, like others in the southern Appalachians, were relatively rich in N and low in base cation status. The combination of high atmospheric N and S deposition, little or no N or S retention, relatively high N mineralization, and extremely acid soils caused soil solutions to be dominated by NO3-, SO4(2-), Al, and H+. Soil solution Al in these sites (most of which was in monomeric form) occasionally reached levels noted to inhibit base cation uptake and root growth in solution culture studies. These pulses of Al were driven by pulses of NO3- and, to a lesser extent, SO4(2-) in soil solution. However, fine roots were present at depths of up to 60 cm in the mineral soil, indicating that Al concentrations had not become consistently toxic to roots. Solution fluxes (both throughfall and soil leaching) exceeded litter-fall fluxes for all the macronutrients at both sites, a typical situation for K and S, but most unusual for N, P, Ca, and Mg. There are significant implications of these fluxes and of the apparent net uptake of N by foliage in terms of how vegetation uptake and translocation are calculated. Some new formulations are suggested, but measurement errors in systems with such a predominance of hydrologic fluxes make foliar leaching and, therefore, uptake and translocation calculations extremely uncertain. Although there are no outward signs of decline in these forests (other than balsam fir (Abies balsamea (L.) Mill.) mortality due to the balsam woolly adelgid (Adelges piceae (Ratz.))), the high rates of NO3- leaching rates and the borderline soil solution Al values suggest that these systems are under stress. Whether these factors actually lead to a dieback or growth decline remains to be seen. C1 UNIV NEVADA,DEPT RANGE WILDLIFE & FORESTRY,RENO,NV 89557. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. UNIV WASHINGTON,COLL FOREST RESOURCES,SEATTLE,WA 98195. RP JOHNSON, DW (reprint author), DESERT RES INST,CTR BIOL SCI,RENO,NV 89506, USA. RI Van Miegroet, Helga/A-1925-2012 NR 76 TC 117 Z9 117 U1 3 U2 13 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0045-5067 J9 CAN J FOREST RES JI Can. J. For. Res.-Rev. Can. Rech. For. PD JUN PY 1991 VL 21 IS 6 BP 769 EP 787 DI 10.1139/x91-110 PG 19 WC Forestry SC Forestry GA FP804 UT WOS:A1991FP80400005 ER PT J AU SINGER, B ESSIGMANN, JM AF SINGER, B ESSIGMANN, JM TI SITE-SPECIFIC MUTAGENESIS - RETROSPECTIVE AND PROSPECTIVE SO CARCINOGENESIS LA English DT Editorial Material ID SINGLE-STRANDED VECTOR; MAMMALIAN O-6-ALKYLGUANINE-DNA ALKYLTRANSFERASE; ACETYLAMINOFLUORENE DNA ADDUCT; GUANINE-INDUCED MUTAGENESIS; THYMINE CYCLOBUTANE DIMER; DEAMINATED PURINE-BASES; RECA MUTATIONS INHIBIT; METHYL-N-NITROSOUREA; Q-BETA-RNA; ESCHERICHIA-COLI C1 MIT,WHITAKER COLL HLTH SCI & TECHNOL,DIV TOXICOL,CAMBRIDGE,MA 02139. MIT,WHITAKER COLL HLTH SCI & TECHNOL,DEPT CHEM,CAMBRIDGE,MA 02139. RP SINGER, B (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,DONNER LAB,BERKELEY,CA 94720, USA. FU NCI NIH HHS [CA 42736, CA 52127] NR 67 TC 170 Z9 171 U1 1 U2 4 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD JUN PY 1991 VL 12 IS 6 BP 949 EP 955 PG 7 WC Oncology SC Oncology GA FQ426 UT WOS:A1991FQ42600001 PM 2044201 ER PT J AU WILD, D WATKINS, BE VANDERLAAN, M AF WILD, D WATKINS, BE VANDERLAAN, M TI AZIDO-PHIP AND NITRO-PHIP, RELATIVES OF THE HETEROCYCLIC ARYLAMINE AND FOOD MUTAGEN PHIP - MECHANISM OF THEIR MUTAGENICITY IN SALMONELLA SO CARCINOGENESIS LA English DT Article ID COOKED-BEEF; 2-AMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE PHIP; METABOLIC-ACTIVATION; AROMATIC-AMINES; DNA ADDUCTS; IQ; 2-AMINO-3-METHYLIMIDAZO<4,5-F>QUINOLINE; IDENTIFICATION; GENOTOXICITY; NITROARENES AB Azido-PhIP (2-azido-1-methyl-6-phenylimidazo[4,5-b]-pyridine) and nitro-PhIP (2-nitro-1-methyl-6-phenylimidazo[4,5-b]pyridine) have been synthesized and characterized chemically. The mutagenic potencies of azido-PhIP (with photoactivation by near UV irradiation), of nitro-PhIP (without exogenous activation) and of the heterocyclic amine PhIP (with activation by rat liver S9) were evaluated by means of the reversion assay in Salmonella typhimurium. Like PhIP, azido- and nitro-PhIP were potent mutagens in the strain TA98. In addition to TA98, the strains YG1024 with increased and TA98/1,8-DNP6 deficient in acetyltransferase activity and TA98NR deficient in nitroreductase were used. Photolysis of azido-PhIP generates a very short-lived mutagen whose mutagenic potency is similar in all strains used and therefore not dependent on the acetyltransferase and nitroreductase. These findings are analogous to previous ones with azidofluorene and suggest that a short-lived DNA-binding arylnitrenium ion is formed directly by the photolysis of azido-PhIP. The nitroreductase contributes to the mutagenic potency of nitro-PhIP; in TA98NR it is 37% of that in TA98. The acetylator status of the strains influences the mutagenic potencies of PhIP and nitro-PhIP only weakly. This contrasts with findings obtained with 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and nitro-IQ and with other amino- and nitro-imidazoarenes which lose most of their mutagenic activity in the acetyltransferase-deficient strain. This atypical behavior of PhIP suggests that the presumed metabolite, N-hydroxy-PhIP, differs from the N-hydroxy metabolites of other heterocyclic amino- and nitro-imidazoarenes in that in Salmonella it is not significantly activated by O-acetylation. It must therefore either react directly with DNA or be activated in a different way. This divergent behavior of PhIP and N-hydroxy-PhIP in Salmonella may also be a key to the understanding of several 'unusual' properties of PhIP in mammalian cells and organisms. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. RP WILD, D (reprint author), UNIV WURZBURG,INST PHARMACOL & TOXICOL,VERSBACHER STR 9,W-8700 WURZBURG,GERMANY. FU NCI NIH HHS [UO1 CA48446-01] NR 35 TC 37 Z9 37 U1 1 U2 1 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD JUN PY 1991 VL 12 IS 6 BP 1091 EP 1096 DI 10.1093/carcin/12.6.1091 PG 6 WC Oncology SC Oncology GA FQ426 UT WOS:A1991FQ42600024 PM 2044190 ER PT J AU KILKIS, B AF KILKIS, B TI COMPUTER-AIDED ANALYSIS OF FLUIDIZED-BED TO EXTERNAL WALL LOCAL HEAT-TRANSFER SO CHEMICAL ENGINEERING JOURNAL AND THE BIOCHEMICAL ENGINEERING JOURNAL LA English DT Article AB Fluidized bed to external wall heat transfer phenomena play an important role in the design and rating of a fluidized bed. In fluidized beds where the heat exchanging surfaces are located along the external walls, maximum heat transfer rates are desirable with a rather uniform distribution over the wall height. Although available models rely upon local hydrodynamic information such as particle velocity and trajectory, gas velocity and void fraction, they cannot provide specific information about these parameters. Instead, the use of global information, derived through certain assumptions or limited analytical expressions, makes the predictions of these models far from realistic. The many empirical equations can provide only average heat transfer rates along the heat exchanging surface and usually yield widely different results. In this study, a computer program was developed to calculate the local bed-to-wall heat transfer, when coupled to the CHEMFLUB computer program which predicts the local hydrodynamics of a fluidized bed [1]. The new program enables the user to adjust various design parameters until a more satisfactory design is reached or to evaluate the heat transfer in the existing beds. This paper is a brief summary of the various heat transfer models and gives sample results for two design cases: a shallow and a narrow bed. Comparisons with available experimental data and correlations are also provided to evaluate the proposed computer model. C1 MORGANTOWN ENERGY TECHNOL CTR,MORGANTOWN,WV 26507. NR 23 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0923-0467 J9 CHEM ENG J BIOCH ENG JI Chem. Eng. J. Biochem. Eng. J. PD JUN PY 1991 VL 46 IS 2 BP 47 EP 60 DI 10.1016/0300-9467(91)80023-P PG 14 WC Engineering, Chemical SC Engineering GA FR653 UT WOS:A1991FR65300001 ER PT J AU FREI, H AF FREI, H TI CHEMISTRY WITH RED AND NEAR-INFRARED LIGHT SO CHIMIA LA English DT Review ID METHYL-SUBSTITUTED POLY(VINYLNAPHTHALENE); IODIDE ACETYLENE COMPLEXES; SINGLET OXYGEN CARRIER; AQUEOUS-SOLUTION; NITROGEN-DIOXIDE; RATE CONSTANTS; VISIBLE-LIGHT; 1,4-DIMETHYLNAPHTHALENE ENDOPEROXIDE; SEMICONDUCTOR ELECTRODES; WAVELENGTH DEPENDENCE AB Opportunities are explored to initiate controlled chemistry by photolysis with long-wavelength visible and near infrared light. In one direction, bimolecular reactions are induced by exciting collisonal pairs in a solid matrix to energy surfaces well below reactant dissociation limits. Examples discussed include product specific (including stereospecific) photo-oxidation of small alkenes and alkynes by NO2, and cycloaddition reactions of singlet SO and singlet O2. Conducting the chemistry in rare gas matrices allows us to elucidate elementary reaction steps by FT-IR spectroscopy of trapped intermediates, and to gain insight into the dynamics of transients by wavelength-dependent laser photochemistry. In the case of olefin epoxidations, stereochemical details of reaction paths are uncovered by chemical trapping of transient oxirane biradicals in their nascent conformation. State-specific reactions of singlet excited SO and singlet O2 with hydrocarbons illustrate how photons deep in the near infrared can be used for controlled chemical synthesis. In parallel work, excited state redox reactions in homogeneous and colloidal semiconductor solutions are explored that pertain to chemical storage of near infrared quanta and conversion into electrical energy. Examples are studies on chemical storage of singlet delta molecular oxygen (O2(1-DELTA)), a metastable near infrared energy carrier, its excited state redox chemistry in aqueous solution, and direct reduction of O2(1-DELTA) at a semiconductor electrode. Using very sensitive time resolved optical techniques, new mechanistic insight is gained on singlet O2 reactions, and on photo-oxidation of halide at the semiconductor-solution interface. RP FREI, H (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720, USA. NR 119 TC 20 Z9 20 U1 2 U2 6 PU NEW SWISS CHEMICAL SOC PI BASEL PA VERLAG HELVETICA CHIMICA ACTA, MALZGASSE 21, POSTFACH 313, CH-4010 BASEL, SWITZERLAND SN 0009-4293 J9 CHIMIA JI Chimia PD JUN PY 1991 VL 45 IS 6 BP 175 EP 190 PG 16 WC Chemistry, Multidisciplinary SC Chemistry GA FV761 UT WOS:A1991FV76100001 ER PT J AU MALANSON, GP WESTMAN, WE AF MALANSON, GP WESTMAN, WE TI MODELING INTERACTIVE EFFECTS OF CLIMATE CHANGE, AIR-POLLUTION, AND FIRE ON A CALIFORNIA SHRUBLAND SO CLIMATIC CHANGE LA English DT Article ID COASTAL SAGE-SCRUB; EASTERN NORTH-AMERICA; SOUTHERN-CALIFORNIA; SIMULATION; SUCCESSION; STRATEGIES; DYNAMICS; FORESTS AB A computer simulation model (FINICS) was used to project the interactive effects of CO2-induced climate change on a drought-deciduous shrubland. FINICS simulates the competitive relations of five dominant shrub species of Californian coastal sage scrub, based on their aboveground growth and reproductive behavior. The model was used to simulate the separate and combined effects of altered precipitation, temperature, ambient ozone levels, and fuel loads and fire intensity, on species composition. Both growth chamber and field data were used to parameterize the model. Projections show that changes attributed to climate variation alone were markedly accentuated when the indirect effects of climate change on fire intensity and ozone pollution were considered. Model results emphasized that change in community composition will result from shifting competitive abilities of individual species under the changed environmental conditions. While neither all of the secondary effects of climate change nor all possible species were included in the model, the projections suggest that inclusion of secondary interactions and species competition will be important in predicting vegetation change realistically. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720. RP MALANSON, GP (reprint author), UNIV IOWA,DEPT GEOG,IOWA CITY,IA 52242, USA. NR 35 TC 18 Z9 18 U1 0 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUN PY 1991 VL 18 IS 4 BP 363 EP 376 DI 10.1007/BF00142967 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA FV753 UT WOS:A1991FV75300002 ER PT J AU PHUOC, TX MATHUR, MP AF PHUOC, TX MATHUR, MP TI TRANSIENT HEATING OF COAL PARTICLES UNDERGOING PYROLYSIS SO COMBUSTION AND FLAME LA English DT Article ID MASS-TRANSFER AB Most of the studies reported to date have viewed the coal devolatilization process as occurring isothermally throughout the coal particle, and transient processes occurring in the interior of coal particle have been largely ignored. However, in pulverized coal combustion processes involving several heating rates and several particle sizes, large temperature gradients are often produced within the coal particles that are undergoing pyrolysis. Large temperature gradients inside the coal particle result in pyrolysis of the coal particle in the following manner. The pyrolysis front first initiated at the particle surface propagates inward into the particle, leaving behind a char layer that gradually thickens as the front moves inward. The present work uses the method of line to theoretically investigate the competition between the motion of the pyrolysis front and the intraparticle heating for coal particles as it undergoes heating and pyrolysis under the effects of heating rate, particle size, particle thermal conductivity, and heat of devolatilization. Two intraparticle heating mechanisms have been identified in this study. The first is the intraparticle diffusion heating where the motion of the pyrolysis front is faster than the rise in the surface temperature but is slower than the rise in the temperature of the unreacted core. As a result, the coal particle is totally pyrolized before the surface temperature reaches its oxidation value. The second mechanism is due to the thermal wave moving with the pyrolysis front where the motion of the pyrolysis front is faster than the rise in the temperature of the unreacted core but is slower than the rise in the coal surface temperature. This may lead to a situation where the surface temperature reaches its oxidation value and only a narrow outer layer close to the surface is pyrolized. RP PHUOC, TX (reprint author), US DOE,PITTSBURGH ENERGY TECHNOL CTR,PITTSBURGH,PA 15236, USA. NR 16 TC 16 Z9 16 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JUN PY 1991 VL 85 IS 3-4 BP 380 EP 388 DI 10.1016/0010-2180(91)90141-W PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA FV210 UT WOS:A1991FV21000008 ER PT J AU GIVLER, RC GARTLING, DK ENGELMAN, MS HAROUTUNIAN, V AF GIVLER, RC GARTLING, DK ENGELMAN, MS HAROUTUNIAN, V TI NAVIER-STOKES SIMULATIONS OF FLOW PAST 3-DIMENSIONAL SUBMARINE MODELS SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article; Proceedings Paper CT SYMP ON RECENT DEVELOPMENTS IN LARGE-SCALE COMPUTATIONAL FLUID DYNAMICS CY APR 23-24, 1990 CL MINNESOTA SUPERCOMP INST, MN SP MINNESOTA SUPERCOMP INST HO MINNESOTA SUPERCOMP INST AB The finite element method has been used to simulate steady, external fluid flows past submarine models at Reynolds number (based upon model length) equal to 1.2 x 10(7). Model geometry is comprised of streamlined appendages attached to an axisymmetric hull. An untuned k-epsilon turbulence model was used to close the Reynolds-averaged, Navier-Stokes equations. Benchmark numerical calculations have been compared with experimental data for flow past an ellipsoid of aspect ratio 6. Convergent numerical solutions for flow past the three-dimensional (3-D) submarine models were obtained using a segregated equation algorithm. These latter numerical simulations resulted in discrete matrix problems involving 325,000 unknowns and required 100 Cray X-MP hours of time on a single central processor. Quality of 3-D numerical solutions can be inferred, in part, from the resolution of the vortical flow structure that emanates from hull/appendage junctures. C1 FLUID DYNAM INT INC,EVANSTON,IL 60201. RP GIVLER, RC (reprint author), SANDIA NATL LABS,DEPT FLUID & THERMAL SCI,ALBUQUERQUE,NM 87185, USA. NR 9 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD JUN PY 1991 VL 87 IS 2-3 BP 175 EP 200 DI 10.1016/0045-7825(91)90005-Q PG 26 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA FU643 UT WOS:A1991FU64300005 ER PT J AU GRESHO, PM AF GRESHO, PM TI SOME CURRENT CFD ISSUES RELEVANT TO THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID FINITE-ELEMENT METHOD; NONLINEAR DIFFERENTIAL-EQUATIONS; SEMIIMPLICIT PROJECTION METHODS; CONSISTENT MASS MATRIX; NUMERICAL-SIMULATION; VISCOUS FLOWS; ALGEBRAIC CONSTRAINTS; SIMPLE BOUNDARIES; PRESSURE; IMPLEMENTATION AB The goals of this paper are to carefully define a particular class of well-set incompressible Navier-Stokes problems in the continuum (partial differential equation/PDE) setting and to discuss some relevant and sometimes poorly understood issues related to these well-posed PDE problems, both in the continuum world and in its computer counterpart. Emphasized are three common formulations used to generate computer codes: the primitive variable (velocity-pressure) formulation and two derived variable formulations (pressure Poisson equation and vorticity transport equation). RP GRESHO, PM (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DIV ATMOSPHER & GEOPHYS SCI, LIVERMORE, CA 94550 USA. NR 76 TC 110 Z9 114 U1 2 U2 11 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD JUN PY 1991 VL 87 IS 2-3 BP 201 EP 252 DI 10.1016/0045-7825(91)90006-R PG 52 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA FU643 UT WOS:A1991FU64300006 ER PT J AU MA, Z GUIOCHON, G AF MA, Z GUIOCHON, G TI APPLICATION OF ORTHOGONAL COLLOCATION ON FINITE-ELEMENTS IN THE SIMULATION OF NONLINEAR CHROMATOGRAPHY SO COMPUTERS & CHEMICAL ENGINEERING LA English DT Article ID NONLINEAR LIQUID-CHROMATOGRAPHY; SEMI-IDEAL MODEL; BAND PROFILES; DISPLACEMENT CHROMATOGRAPHY; NUMERICAL-SIMULATION; BINARY MIXTURE; PROPAGATION; ELUTION; SEPARATION; ADSORPTION AB Orthogonal collocation on finite elements permits the calculation of the chromatographic elution band profiles for one or two components. The individual band profiles obtained for binary mixtures are more accurate than those derived using one of several possible finite difference methods. In most cases, the difference between these profiles is small when the column efficiency is high or the mass transfers between phases in the column are fast. When the concentration of the second eluted component is low compared to the concentration of the first one, however, the front of the second component band is much steeper than predicted by the finite difference method, in agreement with the result of the finite element calculation procedure. The advantage of the better accuracy is compensated by a considerably higher computation time. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 39 TC 61 Z9 65 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0098-1354 J9 COMPUT CHEM ENG JI Comput. Chem. Eng. PD JUN PY 1991 VL 15 IS 6 BP 415 EP 426 DI 10.1016/0098-1354(91)87019-6 PG 12 WC Computer Science, Interdisciplinary Applications; Engineering, Chemical SC Computer Science; Engineering GA GD322 UT WOS:A1991GD32200005 ER PT J AU FRANKLIN, MJ WHITE, DC AF FRANKLIN, MJ WHITE, DC TI BIOCORROSION SO CURRENT OPINION IN BIOTECHNOLOGY LA English DT Article ID CORROSION; COPPER AB Recent studies have demonstrated that mechanisms of microbiologically influenced corrosion are dependent on the biofilm populations as well as the metal substrata, and that this type of corrosion represents a local phenomenon in terms of both microbial biofilm distribution and activity, and electrochemical activity. The combined approaches of electrochemists, material scientists and microbiologists, using new on-line methods, will continue to provide elegant new insights into the complex interactions between multispecies biofilm consortia and metal surfaces. C1 UNIV TENNESSEE,INST APPL MICROBIOL,KNOXVILLE,TN 37932. UNIV TENNESSEE,DEPT MICROBIOL,KNOXVILLE,TN 37932. OAK RIDGE NATL LAB,OAK RIDGE,TN. NR 24 TC 30 Z9 31 U1 1 U2 2 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 0958-1669 J9 CURR OPIN BIOTECH JI Curr. Opin. Biotechnol. PD JUN PY 1991 VL 2 IS 3 BP 450 EP 456 DI 10.1016/S0958-1669(05)80155-7 PG 7 WC Biochemical Research Methods; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA FW896 UT WOS:A1991FW89600018 ER PT J AU ELLINGEN, DC AF ELLINGEN, DC TI INSIDE YOUR DATABASE-MANAGEMENT PROGRAM SO DATABASE LA English DT Article RP ELLINGEN, DC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,ELECTR COMMERCE ELECTR DATA INTERCHANGE PROJECT,POB 808,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ONLINE INC PI WILTON PA 462 DANBURY RD, WILTON, CT 06897-2126 SN 0162-4105 J9 DATABASE JI Database PD JUN PY 1991 VL 14 IS 3 BP 104 EP 106 PG 3 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA FH900 UT WOS:A1991FH90000022 ER PT J AU RENEAU, SL DIETRICH, WE AF RENEAU, SL DIETRICH, WE TI EROSION RATES IN THE SOUTHERN OREGON COAST RANGE - EVIDENCE FOR AN EQUILIBRIUM BETWEEN HILLSLOPE EROSION AND SEDIMENT YIELD SO EARTH SURFACE PROCESSES AND LANDFORMS LA English DT Article DE HILLSLOPE EROSION RATES; SEDIMENT YIELD; COLLUVIUM; HOLLOWS; OREGON COAST RANGE; EQUILIBRIUM ID RADIOCARBON AGE CALIBRATION; WASHINGTON; CALIFORNIA; DENUDATION; LAKE; USA AB The relationship of hillslope erosion rates and sediment yield is often poorly defined because of short periods of measurement and inherent spatial and temporal variability in erosion processes. In landscapes containing hillslopes crenulated by alternating topographic noses and hollows, estimates of local hillslope erosion rates averaged over long time periods can be obtained by analysing colluvial deposits in the hollows. Hollows act as local traps for a portion of the colluvium transported down hillslopes, and erosion rates can be calculated using the age and size of the deposits and the size of the contributing source area. Analysis of colluvial deposits in nine Oregon Coast Range hollows has yielded average colluvial transport rates into the hollows of about 35 cm3 cm-1 yr-1 and average bedrock lowering rates of about 0.07 mm yr-1 for the last 4000 to 15000 yr. These rates are consistent with maximum bedrock exfoliation rates of about 0.09 mm yr-1 calculated from six of the hollows, supporting the interpretation that exfoliation rates limit erosion rates on these slopes. Sediment yield measurements from nine Coast Range streams provide similar basin-wide denudation rates of between 0.05 and 0.08 mm yr-1, suggesting an approximate steady-state between sediment production on hillslopes and sediment yield. In addition, modern sediment yields are similar in basins varying in size from 1 to 1500 km2, suggesting that erosion rates are spatially uniform and providing additional evidence for an approximate equilibrium in the landscape. C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. RP RENEAU, SL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,MAIL STOP D462,LOS ALAMOS,NM 87545, USA. NR 45 TC 103 Z9 103 U1 2 U2 12 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0197-9337 J9 EARTH SURF PROCESSES JI Earth Surf. Process. Landf. PD JUN PY 1991 VL 16 IS 4 BP 307 EP 322 DI 10.1002/esp.3290160405 PG 16 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA FT144 UT WOS:A1991FT14400004 ER PT J AU MULHOLLAND, PJ STEINMAN, AD PALUMBO, AV ELWOOD, JW KIRSCHTEL, DB AF MULHOLLAND, PJ STEINMAN, AD PALUMBO, AV ELWOOD, JW KIRSCHTEL, DB TI ROLE OF NUTRIENT CYCLING AND HERBIVORY IN REGULATING PERIPHYTON COMMUNITIES IN LABORATORY STREAMS SO ECOLOGY LA English DT Article DE ALGAE; CHLOROPHYLL-A; ELIMIA; GRAZING; HERBIVORY; LABORATORY STREAMS; NUTRIENT CYCLING; PERIPHYTON; PRIMARY PRODUCTION ID PRIMARY PRODUCTIVITY; SPECIES COMPOSITION; LEAF DECOMPOSITION; LOTIC PERIPHYTON; BRITISH-COLUMBIA; CURRENT VELOCITY; ALGAL COMMUNITY; WOODLAND STREAM; LIMITED LAKES; ENRICHMENT AB In this study we examined the role of nutrient cycling and herbivory in regulating stream periphyton communities. Population, community, and ecosystem-level properties were studied in laboratory stream channels that had nutrient inputs reduced compared to channels where ambient nutrient levels were maintained. We reduced nutrient inputs in four of eight channels by recirculating 90% of the flow, whereas the other four channels received once-through flow of spring water. We examined the interaction between herbivory and nutrients by varying the number of snails (Elimia clavaeformis) among streams with different nutrient input (circulation) regimes. Reduction in nutrient input via recirculation resulted in lower concentrations of nutrients in the water but did not result in significant differences in biomass, carbon fixation, or algal taxonomic composition. However, herbivory had large effects on these characteristics by reducing biomass and areal rates of carbon fixation and simplifying periphyton taxonomy and physiognomy. Lower rates of nutrient input significantly affected characteristics associated with nutrient cycling. Streams with reduced nutrient inputs had lower periphyton nutrient contents, higher ratios of total: net uptake of P from water, and higher rates of phosphatase activity than streams with ambient nutrient inputs. However, the effects of reduced nutrient input on cycling characteristics were reduced or eliminated by intense herbivory. Our results indicate that nutrient cycling can increase in response to reductions in nutrient input once sufficient biomass or detritus accumulates to facilitate cycling, thereby allowing biomass accrual and carbon fixation rates to be maintained at levels achieved at higher nutrient inputs. In streams with low nutrient input, cycling can meet a large fraction of the nutrient demand of the periphyton. Because our experimental design involved a reduction from ambient nutrient levels rather than the usual enrichment tecnhiques (e.g., additions to water, nutrient-diffusing substrates) in aquatic ecosystems, we have been able to observe how biological structure and processes are influenced by external nutrient inputs at the low natural levels of most undisturbed streams. C1 UNIV LOUISVILLE,DEPT BIOL,LOUISVILLE,KY 40292. RP MULHOLLAND, PJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Palumbo, Anthony/A-4764-2011; Mulholland, Patrick/C-3142-2012; OI Palumbo, Anthony/0000-0002-1102-3975; Steinman, Alan/0000-0002-4886-4305 NR 83 TC 123 Z9 123 U1 2 U2 41 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 0012-9658 J9 ECOLOGY JI Ecology PD JUN PY 1991 VL 72 IS 3 BP 966 EP 982 DI 10.2307/1940597 PG 17 WC Ecology SC Environmental Sciences & Ecology GA FM084 UT WOS:A1991FM08400019 ER PT J AU MUSGRAVE, JA THOMPSON, TB AF MUSGRAVE, JA THOMPSON, TB TI SULTAN MOUNTAIN MINE, WESTERN SAN-JUAN MOUNTAINS, COLORADO - A FLUID INCLUSION AND STABLE ISOTOPE STUDY SO ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS LA English DT Article ID SOUTHWESTERN COLORADO; ORE DEPOSITION; VOLCANIC FIELD; DISTRICT; OXYGEN; SALINITY AB The Sultan Mountain mine, in the western San Juan Mountains of Colorado, has produced Cu-Pb-Zn-Ag-Au ores from the mid-1870s until the 1950s. Production was from veins filling faults and fissures along the southern margin of the Silverton caldera. The principal host rock to the veins is a quartz monzonite stock. Five periods of hypogene mineralization have been recognized: (I) early quartz-pyrite; (II) quartz-pyrite; (III) rhodochrosite-siderite; (IV) main ore-stage chalcopyrite, tetrahedrite, galena, sphalerite, and gold; and (V) quartz-fluorite. Evidence of open-space filling (banding, crustification, vugs) is widespread. Heating studies of fluid inclusions in quartz, rhodochrosite-siderite, sphalerite, and fluorite indicate temperatures were approximately 200-degrees-C for stages I to IV and 186-degrees-C for stage V. Stages I, II, and IV show evidence of boiling. Crushing studies indicate that high-pressure gas, probably CO2, is present in the fluid inclusions. Freezing point depression estimates of salinity, corrected for CO2, indicated a range of 13.6 to 1.3 wt percent NaCl equiv. These data together with P-V-T data for saline solutions and P(CO2) = 38 bars give a minimum depth of formation of 600 m. The delta-O-18 values, at 200-degrees-C, of water calculated for oxygen isotope composition of quartz range from -5.63 to -8.8 per mil and the values for rhodochrosite-siderite are -0.05 and -0.35 per mil. The delta-O-18 values of whole rocks adjacent to the Champion and Alletha veins range from 2.65 to 6.10 per mil. These data suggest hydrothermal fluids were predominantly composed of meteoric water which underwent isotopic exchange with the quartz monzonite. The delta-C-13 values for rhodochrosite-siderite range from -6.9 to -7.3 per mil. Carbon isotope data are inconclusive as to the source of the carbon. The delta-S-34 values for sulfides range from -2.9 to -6.1 per mil, and these limited data suggest a Paleozoic evaporite source for most of the sulfur. Stable isotope data indicate isotopic control of the fluid by the surrounding country rocks. Geologic and geochemical studies suggest a model of Sultan Mountain ore deposition in which predominantly meteoric hydrothermal solutions, restricted mostly to the Sultan Mountain area, scavenged metals from the Precambrian basement and the Tertiary volcanic and intrusive rocks. Sulfur was derived mostly from solution of Paleozoic evaporites; however, the sulfur isotope data indicate some of the sulfur may have been derived from the quartz monzonite stock. The primary mechanism of precipitation of the ore was an increase in pH as a result of boiling. C1 COLORADO STATE UNIV,DEPT EARTH RESOURCES,FT COLLINS,CO 80523. RP MUSGRAVE, JA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,INC-7,MAIL STOP J514,LOS ALAMOS,NM 87545, USA. NR 29 TC 2 Z9 2 U1 1 U2 1 PU ECONOMIC GEOLOGY PUBL CO PI EL PASO PA UNIV TEXAS AT EL PASO ROOM 202 QUINN HALL, EL PASO, TX 79968 SN 0361-0128 J9 ECON GEOL BULL SOC JI Econ. Geol. Bull. Soc. Econ. Geol. PD JUN-JUL PY 1991 VL 86 IS 4 BP 768 EP 779 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FU929 UT WOS:A1991FU92900005 ER PT J AU GEORGE, LS DALLAS, CE BRISBIN, IL EVANS, DL AF GEORGE, LS DALLAS, CE BRISBIN, IL EVANS, DL TI FLOW CYTOMETRIC DNA ANALYSIS OF DUCKS ACCUMULATING CS-137 ON A REACTOR RESERVOIR SO ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY LA English DT Article ID CHINESE-HAMSTER CELLS; IONIZING-RADIATION; DAMAGE C1 UNIV GEORGIA,COLL PHARM,DEPT PHARMACOL & TOXICOL,ATHENS,GA 30602. UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. UNIV GEORGIA,COLL VET MED,DEPT MED MICROBIOL,ATHENS,GA 30602. NR 39 TC 27 Z9 27 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0147-6513 J9 ECOTOX ENVIRON SAFE JI Ecotox. Environ. Safe. PD JUN PY 1991 VL 21 IS 3 BP 337 EP 347 DI 10.1016/0147-6513(91)90073-X PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA FP986 UT WOS:A1991FP98600013 PM 1868790 ER PT J AU HERBERT, JH BURNS, EM AF HERBERT, JH BURNS, EM TI ANALYSIS OF NATURAL-GAS CONSUMPTION IN COMMERCIAL BUILDINGS USING SAMPLE SURVEY DATA SO ENERGY LA English DT Article ID ENERGY AB The use of regression analysis to identify measurement-error problems and to analyze natural-gas consumption in commercial buildings using sample survey data is discussed. The data from the survey are first evaluated. Then, the relationship between weather and consumption of natural gas for a sample of commercial buildings is estimated by using regression techniques. Square footage and other building characteristics are next examined to determine the extent to which these factors can be used to explain estimated heating-degree-day effects from the initial estimation. C1 US DOE,WASHINGTON,DC 20585. NR 14 TC 2 Z9 2 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0360-5442 J9 ENERGY JI Energy PD JUN PY 1991 VL 16 IS 6 BP 903 EP 908 DI 10.1016/0360-5442(91)90041-J PG 6 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA FF846 UT WOS:A1991FF84600003 ER PT J AU URI, ND HERBERT, JH AF URI, ND HERBERT, JH TI THE IMPACT OF MEASUREMENT ERROR ON ESTIMATING THE DEMAND FOR DIESEL FUEL BY FARMERS IN THE UNITED-STATES SO ENERGY LA English DT Article ID PROXY VARIABLES; GAS DEMAND; REGRESSIONS; MODEL AB This paper deals with two diagnostics that are useful in evaluating regression results when one of the explanatory variables contains either random or systematic measurement error. The two diagnostics discussed are regression-coefficient bounds and the bias correction factor. The first is useful because such bound indicate the impact on the estimated regression coefficients not only of the random component in the dependent variable but also of the random component of the explanatory variable (that contains the measurement error). The bias correction factor is useful because, depending on the type of measurement error present, it will indicate the extent of the difference between the true population parameter and the estimated value of the parameter. In an application of the two diagnosis, the demand for diesel fuel by farmers in the United States is explored. Given that the data on the price of diesel fuel contain random measurement error, it is illustrated that the responsiveness of the quantity of diesel fuel demanded by farmers ranges between -1.77 and -0.26% for each 1% change in the price of diesel fuel. In terms of bias arising from measurement error, the responsiveness of the quantity of diesel fuel demanded due to a change in the number of acres planted is under-estimated by 36%. The responsiveness of the quantity demanded due to a change in precipitation is under-estimated by 63%. C1 US DOE,ENERGY INFORMAT ADM,WASHINGTON,DC 20585. RP URI, ND (reprint author), USDA,ECON RES SERV,1301 NEW YORK AVE NW,WASHINGTON,DC 20005, USA. NR 48 TC 0 Z9 0 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0360-5442 J9 ENERGY JI Energy PD JUN PY 1991 VL 16 IS 6 BP 909 EP 921 DI 10.1016/0360-5442(91)90042-K PG 13 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA FF846 UT WOS:A1991FF84600004 ER PT J AU GADGIL, AJ JANNUZZI, GD AF GADGIL, AJ JANNUZZI, GD TI CONSERVATION POTENTIAL OF COMPACT FLUORESCENT LAMPS IN INDIA AND BRAZIL SO ENERGY POLICY LA English DT Article DE BRAZIL; INDIA; ELECTRICITY CONSERVATION ID DEMAND AB We evaluate the conservation potential of compact fluorescent lamps (CFLs) for managing the rapidly increasing electrical energy and peak demand in India and Brazil. The analysis is undertaken from the three separate perspectives of the national economies, the consumers and the utilities. We find that because residential electricity is subsidized, the consumers have little or no incentive to purchase and install the CFLs, unless they too are subsidized. However, the benefits of CFL installation to the utility are so large that subsidizing them is a paying proposition for the utility in almost all cases. We then explore the barriers to immediate large-scale introduction of these lamps in the two countries. Specific technical and marketing problems are identified and discussed, which would require solution before such an introduction can be attempted. Lastly, we list the range of policy instruments, in addition to a subsidy scheme, that can be used for promoting the diffusion of these lamps in the domestic and commercial sectors. C1 UNIV ESTADUAL CAMPINAS,FAC ENGN,BR-13081 CAMPINAS,SP,BRAZIL. RP GADGIL, AJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Jannuzzi, Gilberto/A-6601-2013; OI Jannuzzi, Gilberto/0000-0002-5716-6947; Gadgil, Ashok/0000-0002-0357-9455 NR 24 TC 15 Z9 15 U1 0 U2 2 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD JUN PY 1991 VL 19 IS 5 BP 449 EP 463 DI 10.1016/0301-4215(91)90022-G PG 15 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA FU942 UT WOS:A1991FU94200004 ER PT J AU HADDER, GR DAS, S LEE, R DOMINGO, N DAVIS, RM AF HADDER, GR DAS, S LEE, R DOMINGO, N DAVIS, RM TI ULTRA LOW SULFUR DIESEL FUEL IMPACTS ON AVAILABILITY OF OTHER FUELS SO ENERGY POLICY LA English DT Article DE DIESEL FUEL; JET FUEL; ENVIRONMENTAL REGULATIONS AB Legislation for ultra low sulphur (ULS) diesel fuel, with a greatly reduced allowable sulphur content and a new limit on aromatics content, is expected to be in place in the USA by 1995. The ULS diesel fuel has been specified to satisfy US standards for particulate emissions from heavy-duty diesel engines. The Navy Mobility Fuels Forecasting System has been used to study the impacts of ULS diesel fuel production on other refined petroleum products. The study predicts that to produce ULS diesel fuel, US Gulf and west coast refiners will have to invest about $4.4 billion in new processing capacity. Refiners will shift aromatics from No 2 diesel fuel to jet fuel and to No 2 fuel oil. Therefore, particulate emissions could be transferred from highways to airways and to communities which use No 2 fuel oil for residential and commercial heating. The study also predicts that there will be an increase in the aromatics content of Navy JP-5 jet fuel and F-76 marine diesel fuel produced in the USA. The gum-forming tendencies of F-76 and F-77 burner fuel oil will increase in most cases. The freezing point of JP-5 will improve. There will be minor changes in the cost of JP-5, but sizable reductions in the cost of F-76 and F-77. RP HADDER, GR (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,POB 2008,OAK RIDGE,TN 37831, USA. NR 17 TC 0 Z9 0 U1 1 U2 1 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD JUN PY 1991 VL 19 IS 5 BP 488 EP 493 DI 10.1016/0301-4215(91)90026-K PG 6 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA FU942 UT WOS:A1991FU94200008 ER PT J AU TONN, B AF TONN, B TI RESEARCH POLICY AND REVIEW 34 - THE DEVELOPMENT OF IDEAS OF UNCERTAINTY REPRESENTATION SO ENVIRONMENT AND PLANNING A LA English DT Article ID SUBJECTIVE-PROBABILITY; DECISION; RISK RP TONN, B (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831, USA. NR 76 TC 1 Z9 1 U1 1 U2 2 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON, ENGLAND NW2 5JN SN 0308-518X J9 ENVIRON PLANN A JI Environ. Plan. A PD JUN PY 1991 VL 23 IS 6 BP 783 EP 812 DI 10.1068/a230783 PG 30 WC Environmental Studies; Geography SC Environmental Sciences & Ecology; Geography GA FV484 UT WOS:A1991FV48400003 ER PT J AU GOLD, LS SLONE, TH MANLEY, NB BERNSTEIN, L AF GOLD, LS SLONE, TH MANLEY, NB BERNSTEIN, L TI TARGET ORGANS IN CHRONIC BIOASSAYS OF 533 CHEMICAL CARCINOGENS SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article ID POTENCY DATABASE; ANIMAL BIOASSAYS; CHRONOLOGICAL SUPPLEMENT AB A compendium of carcinogenesis bioassay results organized by target organ is presented for 533 chemicals that are carcinogenic in at least one species. This compendium is based primarily on experiments in rats or mice; results in hamsters, nonhuman primates, and dogs are also reported. The compendium can be used to identify chemicals that induce tumors at particular sites, and to determine whether target sites are the same for chemicals positive in more than one species. The Carcinogenic Potency Database (CPDB), which includes results of 3969 experiments, is used in the analysis. The published CPDB includes details on each test, and literature references. Chemical carcinogens are reported for 35 different target organs in rats or mice. More than 80% of the carcinogens in each of these species are positive in at least one of the 8 most frequent target sites: liver, lung, mammary gland, stomach, vascular system, kidney, hematopoietic system, and urinary bladder. An analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa. Among chemicals tested in both species, 76% of rat carcinogens are positive in mice, and 71% of mouse carcinogens are positive in rats. Prediction is less accurate to the same target site: 52% of rat carcinogens are positive in the same site in mice, and 48% of mouse carcinogens are positive in the same site in rats. The liver is the most frequent site in common between rats and mice. C1 UNIV CALIF BERKELEY,DIV BIOCHEM & MOLEC BIOL,BERKELEY,CA 94720. UNIV SO CALIF,SCH MED,DEPT PREVENT MED,LOS ANGELES,CA 90033. RP GOLD, LS (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720, USA. FU NCRR NIH HHS [2S07RR05918]; NIEHS NIH HHS [ES01896] NR 12 TC 98 Z9 98 U1 1 U2 3 PU NATL INST ENVIRON HEALTH SCI PI RES TRIANGLE PK PA PO BOX 12233, RES TRIANGLE PK, NC 27709 SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD JUN PY 1991 VL 93 BP 233 EP 246 DI 10.2307/3431194 PG 14 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA GC052 UT WOS:A1991GC05200035 PM 1773795 ER PT J AU ROSEN, JF MARKOWITZ, ME BIJUR, PE JENKS, ST WIELOPOLSKI, L KALEFEZRA, JA SLATKIN, DN AF ROSEN, JF MARKOWITZ, ME BIJUR, PE JENKS, ST WIELOPOLSKI, L KALEFEZRA, JA SLATKIN, DN TI SEQUENTIAL MEASUREMENTS OF BONE LEAD CONTENT BY L X-RAY-FLUORESCENCE IN CANA2EDTA-TREATED LEAD-TOXIC CHILDREN SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article ID BLOOD LEAD; INVIVO MEASUREMENT; EXPOSURE; HEALTH; RISK AB With the development of L X-ray fluorescence (LXRF) to measure cortical bone lead directly, safely, rapidly, and noninvasively, the present study was undertaken to alpha) evaluate LXRF as a possible replacement for the CaNa2EDTA test; b) quantify lead in tibial cortical bones of mildly to moderately lead-toxic children before treatment; and c) quantify lead in tibial cortical bones of lead-toxic children sequentially following one to two courses of chelation therapy. The clinical research design was based upon a longitudinal assessment of 59 untreated lead-toxic children. At enrollment, if the blood lead (PbB) was 25 to 55-mu-g/dL and the erythrocyte protoporphyrin (EP) concentration was greater-than-or-equal-to 35-mu-g/dL, LXRF measurement of tibial bone lead was carried out. One day later, each child underwent a CaNa2EDTA provocative test. If this test was positive, lead-toxic children were admitted to the hospital for 5 days of CaNa2EDTA therapy. These tests were repeated 6 weeks and 6 months after enrollment. Abatement of lead paint hazards was achieved in most apartments by the time of initial hospital discharge. The LXRF instrument consists of a low energy X-ray generator with a silver anode, a lithium-doped silicon detector, a polarizer of incident photons, and a multichannel X-ray analyzer. Partially polarized photons are directed at the subcutaneous, medial mid-tibial cortical bone. The LXRF spectrum, measured 90-degrees from the incident beam, reveals a peak in the 10.5 KeV region, which represents the lead L-alpha line. The effective dose equivalent using tissue weighting factors according to guidelines of the National Council on Radiation Protection and Measurements (1988), was 2.5-mu-Sv. The reproducibility of replicate LXRF measurements, including the day-to-day variation of the instrument, in 26 lead-toxic children, after repositioning the instrument within 4 cm of the first LXRF measurements, was +/- 9.2% (95% confidence limits). For an overlying tibial skin thickness of 5 mm, the minimum detection limit was 7-mu-g of lead/g (wet weight) at the 95% confidence interval. Based upon a discriminant analysis, 90% of lead-toxic children were predicted correctly as being CaNa2EDTA positive or CaNa2EDTA-negative. Using LXRF and PbB values to predict CaNa2EDTA outcomes, the specificity and sensitivity of these two predictors were 86 and 93%, respectively. In a significant fraction of CaNa2EDTA-positive and CaNa2EDTA-negative children, cortical bone lead values were similar to lead concentrations measured via bone biopsy in normal adults and lead workers in industry. By 24 weeks after enrollment, PbB, EP, and urinary lead/EDTA ratios were similar in all groups. The most dramatic in net connected photon counts by LXRF occurred in children treated twice. Mean values of cortical bone lead by LXRF at 24 weeks in all three groups of children were similar to the mean concentration in untreated CaNa2EDTA-negative children at enrollment and still three to five times greater than those measured in the tibia or whole teeth of normal European children using atomic absorption. In lead-toxic children who did not qualify for treatment, additional significant accumulation of lead in bone ended once children were removed from leaded environments or returned to lead-abated apartments. These data suggest that LXRF measurements of lead in tibial cortical bone have considerable promise to replace the CaNa2EDTA test and to provide a more appropriate end point of chelation therapy than the conventional indices of PbB and EP. Moreover, markedly elevated bone lead values accumulated during early childhood may have an intergenerational impact, as maternal lead stores amassed during childhood cross the placenta and directly affect the developing fetus. C1 MONTEFIORE MED CTR,ALBERT EINSTEIN COLL MED,DIV EPIDEMIOL,BRONX,NY 10467. SUNY STONY BROOK,DEPT RADIAT ONCOL,STONY BROOK,NY 11794. UNIV IOANNINA,SCH MED,MED PHYS LAB,IOANNINA,GREECE. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP ROSEN, JF (reprint author), MONTEFIORE MED CTR,ALBERT EINSTEIN COLL MED,DEPT PEDIAT,DIV PEDIAT METAB,BRONX,NY 10467, USA. FU NIEHS NIH HHS [ES04039] NR 29 TC 24 Z9 25 U1 1 U2 2 PU NATL INST ENVIRON HEALTH SCI PI RES TRIANGLE PK PA PO BOX 12233, RES TRIANGLE PK, NC 27709 SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD JUN PY 1991 VL 93 BP 271 EP 277 DI 10.2307/3431196 PG 7 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA GC052 UT WOS:A1991GC05200037 PM 1773798 ER PT J AU MCLEAN, RI SUMMERS, JK OLSEN, CR DOMOTOR, SL LARSEN, IL WILSON, H AF MCLEAN, RI SUMMERS, JK OLSEN, CR DOMOTOR, SL LARSEN, IL WILSON, H TI SEDIMENT ACCUMULATION RATES IN CONOWINGO RESERVOIR AS DETERMINED BY MAN-MADE AND NATURAL RADIONUCLIDES SO ESTUARIES LA English DT Article ID ADIRONDACK LAKE-SEDIMENTS; SUSQUEHANNA RIVER; CHESAPEAKE BAY; CS-137; DISCHARGE; PB-210 AB The Susquehanna River is the major contributor to sediment loadings in the Chesapeake Bay. Because many environmental contaminants are associated with suspended particulates, the degree of particle retention within the reservoirs of the lower Susquehanna River is an important consideration in evaluating contaminant loadings to the Chesapeake Bay. Profiles of weapons-test Cs-137, nuclear power plant-related Cs-134 and Cs-137, and naturally-derived Pb-210 were used to estimate rates of sediment accretion in the Conowingo Reservoir, an impoundment of the Susquehanna River along the Maryland-Pennsylvania border. Net accretion rates ranged from about 2 cm yr-1 downstream of a nuclear power plant cooling discharge to a high of about 7 cm yr-1 at the mount of an incoming creek. Slight, but consistent, increases in the annual rate of accretion since the creation of the reservoir in 1928 are apparent. The current net average annual sediment load retained by the reservoir is estimated to be 0.4 x 10(6) to 1.5 x 10(6) metric tons yr-1. The retained sediment load represents about 8-23% of the long-time average sediment input to the reservoir. C1 VERSAR INC,DIV ECOL SCI,COLUMBIA,MD 21045. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. RP MCLEAN, RI (reprint author), MARYLAND DEPT NAT RESOURCES,DIV POWER PLANT & ENVIRONM REVIEW,TAWES BLDG,ANNAPOLIS,MD 21401, USA. NR 19 TC 9 Z9 9 U1 0 U2 1 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 1991 VL 14 IS 2 BP 148 EP 156 DI 10.2307/1351688 PG 9 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA FW846 UT WOS:A1991FW84600005 ER PT J AU SABOUNGI, ML PRICE, DL SCAMEHORN, C TOSI, MP AF SABOUNGI, ML PRICE, DL SCAMEHORN, C TOSI, MP TI MELTING IN TRIVALENT METAL CHLORIDES SO EUROPHYSICS LETTERS LA English DT Article ID EARTH CHLORIDES; MOLTEN-SALTS; VISCOSITY; DYNAMICS; BROMIDES; IODIDES; ALKALI AB We report a neutron diffraction study of the liquid structure of YCl3 and combine the structural data with macroscopic melting and transport data to contrast the behaviour of this molten salt with those of SrCl2, ZnCl2 and AlCl3 as prototypes of different melting mechanisms for ionic materials. A novel melting mechanism for trivalent metal chlorides, leading to a loose disordered network of edge-sharing octahedral units in the liquid phase, is thereby established. The various melting behaviours are related to bonding character with the help of Pettifor's phenomenological chemical scale. C1 UNIV TRIESTE,DEPT THEORET PHYS 1,I-34127 TRIESTE,ITALY. INT CTR THEORET PHYS,I-34100 TRIESTE,ITALY. RP SABOUNGI, ML (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 25 TC 86 Z9 88 U1 0 U2 8 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 JUN 1 PY 1991 VL 15 IS 3 BP 283 EP 288 DI 10.1209/0295-5075/15/3/009 PG 6 WC Physics, Multidisciplinary SC Physics GA FN933 UT WOS:A1991FN93300009 ER PT J AU SUTTON, MA TURNER, JL BRUCK, HA CHAE, TA AF SUTTON, MA TURNER, JL BRUCK, HA CHAE, TA TI FULL-FIELD REPRESENTATION OF DISCRETELY SAMPLED SURFACE DEFORMATION FOR DISPLACEMENT AND STRAIN ANALYSIS SO EXPERIMENTAL MECHANICS LA English DT Article ID SMOOTHING NOISY DATA; SPLINE FUNCTIONS; DIFFERENTIATION AB A detailed evaluation of the feasibility of determining displacements and displacement gradients from measured surface displacement fields is presented. An improved methodology for both the estimation and elimination of noise is proposed. The methodology is used to analyze the gradients for three tests: (1) uniform rotation, (2) uniform strain, and (3) crack-tip displacement fields. Results of the study indicate that the proposed methodology can be used to extract the underlying two-dimensional displacements and their corresponding gradients from the noisy data with reasonable accuracy. Specifically, it is shown that (a) the digital correlation method for acquiring displacement fields has an error in strain of approximately 150-mu-strain at each point, (b) the average strain in a region of uniform strain has much less error, typically on the order of 20-mu-strain, (c) the displacement 'noise' present in digital correlation is very small, approximately 0.01 pixels, (d) the proposed methodology for reducing noise in the data is essential to the accurate evaluation of displacement gradients and (e) the successful evaluation of displacement and displacement gradients for all three cases indicates that the proposed methodology can be used both to quantify the displacement fields and to reasonably estimate the overall gradient trends. C1 FIRESTONE CENT RES LAB,AKRON,OH 44317. SAVANNAH RIVER SITE,AIKEN,SC 29803. CALTECH,PASADENA,CA 91125. RP SUTTON, MA (reprint author), UNIV S CAROLINA,DEPT MECH ENGN,COLUMBIA,SC 29208, USA. NR 16 TC 177 Z9 184 U1 0 U2 11 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD JUN PY 1991 VL 31 IS 2 BP 168 EP 177 DI 10.1007/BF02327571 PG 10 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA FX638 UT WOS:A1991FX63800014 ER PT J AU PAI, SR KUBITSCHEK, HE AF PAI, SR KUBITSCHEK, HE TI THE PHOSPHATE POOL IN ESCHERICHIA-COLI THU SO FEMS MICROBIOLOGY LETTERS LA English DT Article DE ESCHERICHIA-COLI THU; PHOSPHATE POOL ID DIVISION CYCLE AB The phosphate pool of Escherichia coli was determined as a fraction of the total cell phosphate. This relative pool size was found to be essentially independent of cell age. C1 ARGONNE NATL LAB,DIV BIOL ENVIRONM & MED RES,ARGONNE,IL 60439. NR 4 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1097 J9 FEMS MICROBIOL LETT JI FEMS Microbiol. Lett. PD JUN 1 PY 1991 VL 81 IS 1 BP 49 EP 52 DI 10.1016/0378-1097(91)90469-Q PG 4 WC Microbiology SC Microbiology GA FT295 UT WOS:A1991FT29500009 ER PT J AU RIVKIN, DB CASEY, LA AF RIVKIN, DB CASEY, LA TI WAR POWERS SO FOREIGN AFFAIRS LA English DT Letter RP RIVKIN, DB (reprint author), US DOE,WASHINGTON,DC, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU COUNC FOREIGN RELAT INC PI NEW YORK PA 58 E 68TH ST, NEW YORK, NY 10021 SN 0015-7120 J9 FOREIGN AFF JI Foreign Aff. PD SUM PY 1991 VL 70 IS 3 BP 150 EP 153 PG 4 WC International Relations SC International Relations GA GU828 UT WOS:A1991GU82800010 ER PT J AU TONN, BE AF TONN, BE TI THE COURT OF GENERATIONS - A PROPOSED AMENDMENT TO THE UNITED-STATES CONSTITUTION SO FUTURES LA English DT Article RP TONN, BE (reprint author), OAK RIDGE NATL LAB,POB 20008,OAK RIDGE,TN 37831, USA. NR 17 TC 11 Z9 11 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0016-3287 J9 FUTURES JI Futures PD JUN PY 1991 VL 23 IS 5 BP 482 EP 498 DI 10.1016/0016-3287(91)90097-L PG 17 WC Economics; Planning & Development SC Business & Economics; Public Administration GA FU548 UT WOS:A1991FU54800003 ER PT J AU CHEN, LZ HARRIS, PC APOSTOLOU, S BAKER, E HOLMAN, K LANE, SA NANCARROW, JK WHITMORE, SA STALLINGS, RL HILDEBRAND, CE RICHARDS, RI SUTHERLAND, GR CALLEN, DF AF CHEN, LZ HARRIS, PC APOSTOLOU, S BAKER, E HOLMAN, K LANE, SA NANCARROW, JK WHITMORE, SA STALLINGS, RL HILDEBRAND, CE RICHARDS, RI SUTHERLAND, GR CALLEN, DF TI A REFINED PHYSICAL MAP OF THE LONG ARM OF HUMAN CHROMOSOME-16 SO GENOMICS LA English DT Article ID ANONYMOUS DNA PROBES; DELETION; HYBRIDIZATION; ASSIGNMENT; PHENOTYPE; SEQUENCES; LIBRARY; GENE C1 JOHN RADCLIFFE HOSP,INST MOLEC MED,OXFORD OX3 9DU,ENGLAND. UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. RP CHEN, LZ (reprint author), ADELAIDE CHILDRENS HOSP INC,DEPT CYTOGENET & MOLEC GENET,ADELAIDE,SA 5006,AUSTRALIA. RI Stallings, Raymond/A-7213-2008; Sutherland, Grant/D-2606-2012; Callen, David/G-1975-2012; OI Callen, David/0000-0002-6189-9991 NR 21 TC 13 Z9 13 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 0888-7543 J9 GENOMICS JI Genomics PD JUN PY 1991 VL 10 IS 2 BP 308 EP 312 DI 10.1016/0888-7543(91)90313-4 PG 5 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA FL240 UT WOS:A1991FL24000002 PM 2071140 ER PT J AU ZACHARA, JM COWAN, CE RESCH, CT AF ZACHARA, JM COWAN, CE RESCH, CT TI SORPTION OF DIVALENT METALS ON CALCITE SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID DISTRIBUTION COEFFICIENTS; SURFACE PRECIPITATION; STABILITY-CONSTANTS; MINERAL SURFACES; ISOTOPE-EXCHANGE; DILUTE-SOLUTIONS; TRACE-METALS; SEA-WATER; CARBONATE; ADSORPTION AB The sorption of seven divalent metals (Ba, Sr, Cd, Mn, Zn, Co, and Ni) was measured on calcite over a large initial metal (Me) concentration range (10(-8) to 10(-4) mol/L) in constant ionic strength (I = 0.1), equilibrium CaCO3(s)-CaCO3(aq) suspensions that varied in pH. At higher initial Me concentrations (10(-5) to 10(-4) mol/L) geochemical calculations indicated that the equilibrium solutions were saturated with discrete solid phases of the sorbates: CdCO3(s), MnCO3(s), Zn5(OH)6(CO3)2(s), Co(OH)2(s), and Ni(OH)2(s), implying that aqueous concentrations were governed by solubility. However, significant sorption of all the metals except for Ba and Sr was observed at aqueous concentrations below saturation with Me-solid phases. Divalent metal ion sorption was dependent on aqueous Ca concentration, and the following selectivity sequence was observed: Cd > Zn greater-than-or-equal-to Mn > Co > Ni >> Ba = Sr. The metals varied in their sorption reversibility, which was correlated with the single-ion hydration energies of the metal sorbates. The strongly hydrated metals (Zn, Co, and Ni) were most desorbable. A sorption model that included aqueous speciation and Me2+-Ca2+ exchange on cation-specific surface sites was developed that described most of the data well. The chemical nature of the surface complex used in this model was unspecified and could represent either a hydrated or dehydrated surface complex, or a surface precipitate. A single exchange constant for Cd, Mn, Co, and Ni could describe the sorption of that metal over a wide range in pH, Ca concentration, and surface concentration. Zinc, however, exhibited nonlinear sorption behavior and required exchange constants that varied with surface coverage. Our data suggested that (i) Cd and Mn dehydrate soon after their adsorption to calcite and form a phase that behaves like a surface precipitate, and (ii) Zn, Co, and Ni form surface complexes that remain hydrated until the ions are incorporated into the structure by recrystallization. RP ZACHARA, JM (reprint author), PACIFIC NW LAB, DEPT GEOSCI, RICHLAND, WA 99352 USA. NR 74 TC 288 Z9 296 U1 6 U2 77 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1991 VL 55 IS 6 BP 1549 EP 1562 DI 10.1016/0016-7037(91)90127-Q PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FU772 UT WOS:A1991FU77200006 ER PT J AU KOIDE, M GOLDBERG, ED NIEMEYER, S GERLACH, D HODGE, V BERTINE, KK PADOVA, A AF KOIDE, M GOLDBERG, ED NIEMEYER, S GERLACH, D HODGE, V BERTINE, KK PADOVA, A TI OSMIUM IN MARINE-SEDIMENTS SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SYSTEMATICS AB Osmium is enriched in ferromanganese minerals, and its concentrations follow those of other Pt-group metals except Pd. Oxidative capture during solid formation is the probable mechanism for uptake. In some sediments forming under reducing conditions (phosphorites and anoxic coastal deposits) there is also an enrichment. This may relate to reductive capture, although deposits also formed under reducing conditions from hydrothermal areas are depleted in osmium. C1 SAN DIEGO STATE UNIV,SAN DIEGO,CA 92182. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV NEVADA,LAS VEGAS,NV 89154. ISRAEL ATOM ENERGY COMMISS,IL-770600 YAVNE,ISRAEL. RP KOIDE, M (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,LA JOLLA,CA 92093, USA. NR 16 TC 46 Z9 51 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1991 VL 55 IS 6 BP 1641 EP 1648 DI 10.1016/0016-7037(91)90135-R PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FU772 UT WOS:A1991FU77200014 ER PT J AU CHERNIAK, DJ LANFORD, WA RYERSON, FJ AF CHERNIAK, DJ LANFORD, WA RYERSON, FJ TI LEAD DIFFUSION IN APATITE AND ZIRCON USING ION-IMPLANTATION AND RUTHERFORD BACKSCATTERING TECHNIQUES SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID RADIOACTIVE-WASTE; OXYGEN; BOMBARDMENT; TEMPERATURE; AGE; PB; COEFFICIENTS; FLUORAPATITE; STRONTIUM; RADIATION AB Ion implantation was used to introduce Pb into the minerals zircon and apatite. Diffusion profiles were obtained using Rutherford Backscattering, and the results were fitted with a model to determine the diffusion coefficients. This approach is both simple and useful in studying diffusion over a temperature range of geologic interest without inordinate annealing times. Results for apatite over the temperature range 600-900-degrees-C are in good agreement with earlier results obtained for higher temperatures (WATSON et al., 1985) and are described by the following Arrhenius Law: [GRAPHICS] This suggests that radiation damage induced by ion implantation has little effect on Pb diffusion in this case due to rapid annealing of induced damage at low temperatures. The activation energy stated above is somewhat smaller than that previously determined (70 kcal mol-1), reflecting the larger range in 1/T sampled by the present results. Closure temperatures calculated with these diffusion parameters are in good agreement with those inferred from geochronologic data. Diffusion coefficients for Pb in zircon determined in this study are greater than those obtained from a single experimental measurement and estimates of Pb diffusion based on geochronologic data and U/Pb zoning in natural zircons. The differing results for zircon and apatite obtained in this study appear to be related to each mineral's ability to anneal the radiation damage induced by ion implantation. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. SUNY ALBANY,DEPT PHYS,ALBANY,NY 12222. NR 63 TC 239 Z9 244 U1 0 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUN PY 1991 VL 55 IS 6 BP 1663 EP 1673 DI 10.1016/0016-7037(91)90137-T PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FU772 UT WOS:A1991FU77200016 ER PT J AU MARTEL, SJ ZIMMERMAN, RW AF MARTEL, SJ ZIMMERMAN, RW TI APPLICATION OF LINEAR ELASTIC FRACTURE-MECHANICS TO THE QUANTITATIVE-EVALUATION OF FLUID-INCLUSION DECREPITATION - COMMENT SO GEOLOGY LA English DT Note RP MARTEL, SJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720, USA. NR 7 TC 1 Z9 1 U1 1 U2 2 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD JUN PY 1991 VL 19 IS 6 BP 663 EP 664 DI 10.1130/0091-7613(1991)019<0663:CAROAO>2.3.CO;2 PG 2 WC Geology SC Geology GA FQ661 UT WOS:A1991FQ66100032 ER PT J AU MILLER, RH GARY, SP WINSKE, D GOMBOSI, TI AF MILLER, RH GARY, SP WINSKE, D GOMBOSI, TI TI PITCH ANGLE SCATTERING OF COMETARY IONS INTO MONOSPHERICAL AND BISPHERICAL DISTRIBUTIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COMPUTER-SIMULATIONS; VELOCITY DISTRIBUTIONS; BEAM INSTABILITIES; SOLAR-WIND; ENVIRONMENT AB Low frequency magnetic fluctuations generated by solar wind/cometary ion distributions cause pitch-angle scattering of cometary ions. The nature of this pitch angle scattering is examined by means of one-dimensional hybrid simulations, in which newborn ions are created at a constant rate, and for various injection angles, alpha, relative to the magnetic field. Pitch angle scattering in the quasi-perpendicular regime (alpha > 60-degrees) results in a bispherical velocity distribution while in the quasi-parallel regime (0 less-than-or-equal-to alpha less-than-or-equal-to 60-degrees), pitch angle scattering can result in either a mono or bispherical distribution depending on the injection angle and initial beam velocity. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV SPACE & SCI TECHNOL,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545. RP MILLER, RH (reprint author), UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES LAB,ANN ARBOR,MI 48109, USA. RI Gombosi, Tamas/G-4238-2011 OI Gombosi, Tamas/0000-0001-9360-4951 NR 17 TC 20 Z9 20 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN PY 1991 VL 18 IS 6 BP 1063 EP 1066 DI 10.1029/91GL01047 PG 4 WC Geosciences, Multidisciplinary SC Geology GA FR190 UT WOS:A1991FR19000020 ER PT J AU GARY, SP MILLER, RH WINSKE, D AF GARY, SP MILLER, RH WINSKE, D TI PITCH-ANGLE SCATTERING OF COMETARY IONS - COMPUTER-SIMULATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WATER GROUP IONS; SOLAR-WIND; VELOCITY DISTRIBUTIONS; PICKUP IONS; BOW SHOCK; INSTABILITIES; NEWBORN; TURBULENCE; PROTONS; HALLEY AB Pitch-angle evolution of newborn cometary ions is studied by means of one-dimensional electromagnetic hybrid computer simulations of homogeneous plasmas. Newborn ions are injected into the simulations at a constant rate, with a velocity relative to the solar wind which makes an angle alpha with respect to the ambient magnetic field. The simulations are done with relatively weak ion injection rates commensurate with those in the distant environment of comet Halley. In response to the linear temporal growth of the fluctuating magnetic field energy, the injected ions pitch-angle scatter toward isotropy in both the quasiparallel (0-degree less-than-or-equal-to alpha less-than-or-similar-to 60-degrees) and quasiperpendicular (60-degrees < alpha less-than-or-equal-to 90-degrees) regimes. For the injection of cometary oxygen ions the simulations show pitch angle scattering rates that are essentially independent of the solar wind ion/cometary ion relative speed, and increase as the square root of the injection rate. Furthermore, the xygen ion pitch angle scattering rate at perpendicular injection is approximately twice that in the quasiparallel regime, in qualitative agreement with observations at comet Halley. C1 UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. RP GARY, SP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 21 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN PY 1991 VL 18 IS 6 BP 1067 EP 1070 DI 10.1029/91GL01331 PG 4 WC Geosciences, Multidisciplinary SC Geology GA FR190 UT WOS:A1991FR19000021 ER PT J AU JODY, BJ DANIELS, EJ AF JODY, BJ DANIELS, EJ TI AUTOMOBILE SHREDDER RESIDUE - TREATMENT OPTIONS SO HAZARDOUS WASTE & HAZARDOUS MATERIALS LA English DT Article AB The single largest source of recycled ferrous scrap for the iron and steel industry is obsolete automobiles. The process of recovering reusable metals from obsolete automobiles leaves the automobile shredder operator with nonmetallic automobile shredder residue (ASR), termed "fluff," that must be disposed of. The disposal cost affects the viability of the automobile shredder industry and, in turn, the supply and price of high-quality scrap for the iron and steel industry. Rising disposal costs are further exacerbated in that the percentage of fluff that must be disposed of, compared with the percentage of marketable recovered metals, is increasing because of the increasing content of plastics in automobiles. Argonne National Laboratory, in cooperation with the Institute of Scrap Recycling Industries, is systematically assessing alternatives for recycling ASR. The objective is to reduce the escalating costs of metals recycling. In the absence of a commercially viable automobile shredder industry, the outcome would be increased environmental insult and a decreased supply of quality scrap, which would result in the production of finished metals from primary ores. This paper discusses the available technologies for the treatment of ASR. RP JODY, BJ (reprint author), ARGONNE NATL LAB,DIV ENERGY SYST,9700 S CASS AVE,ES-362,ARGONNE,IL 60439, USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 0882-5696 J9 HAZARD WASTE HAZARD JI Hazard. Waste Hazard. Mater. PD SUM PY 1991 VL 8 IS 3 BP 219 EP 230 DI 10.1089/hwm.1991.8.219 PG 12 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA GM928 UT WOS:A1991GM92800004 ER PT J AU TSAI, TS AF TSAI, TS TI BIOTREATMENT OF RED WATER - A HAZARDOUS-WASTE STREAM FROM EXPLOSIVE MANUFACTURE - WITH FUNGAL SYSTEMS SO HAZARDOUS WASTE & HAZARDOUS MATERIALS LA English DT Article AB Improper management of red water generated during the manufacture of trinitrotoluene (TNT) is an environmental concern because it can result in soil and groundwater contamination. Past methods for the management of this hazardous waste stream did not fully meet pollution compliance or were not cost effective. The lignin peroxidase (ligninase) secreted by the white rot fungus (Phanerochaete chrysosporium) has been shown in other studies to degrade a broad spectrum of organic pollutants. In this study, the efficacy of treating red water with the P. chrysosporium system was investigated. Red water samples obtained from a munition plant were pretreated with ultraviolet (UV) light and incubated under various conditions with fungal culture or crude extracellular enzyme prepared from the culture. The treated samples were analyzed for decolorization and ligninase activity and by UV spectral analysis, high performance liquid chromatography (HPLC) metabolite analysis, and bacterial toxicity screening. Red color intensity was reduced in all treated samples. UV spectral analysis showed a progressive decrease in the aromatic region (200-300 nm). HPLC analysis demonstrated a decrease in the 2,4,6-trinitrobenzenesulfonic acid peak and diminished TNT, 2,4-dinitrotoluene (DNT), and 2,6-DNT peaks in red water samples treated with concentrated fungal enzyme preparation. The same treatment also reduced the toxicity of the red water as tested by a bioassay. The results of this study suggest that the white rot fungal system is effective in biodegrading and reducing biotoxicity of red water in one week under controlled laboratory conditions. C1 ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. NR 0 TC 15 Z9 16 U1 2 U2 7 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 0882-5696 J9 HAZARD WASTE HAZARD JI Hazard. Waste Hazard. Mater. PD SUM PY 1991 VL 8 IS 3 BP 231 EP 244 DI 10.1089/hwm.1991.8.231 PG 14 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA GM928 UT WOS:A1991GM92800005 ER PT J AU MURPHY, MK TRAUB, RJ MCDONALD, JC HOOKER, CD AF MURPHY, MK TRAUB, RJ MCDONALD, JC HOOKER, CD TI PHYSICAL CHARACTERIZATION OF A 137CS FIELD USED FOR PROFICIENCY-TEST IRRADIATIONS SO HEALTH PHYSICS LA English DT Article AB This paper describes a series of measurements and calculations that were undertaken at the Pacific Northwest Laboratory to determine the physical and dosimetric characteristics of a Cs-137 source, which is housed within a commercially manufactured irradiator. These measurements and calculations helped to demonstrate that: (1) the exposure rate for this source was consistent with (traceable to) radiation standards maintained by the National Institute of Standards and Technology; (2) the radiation field at the surface of the irradiation phantom, in a 10 cm x 10 cm central area, was uniform to within +/- 2%; (3) the contribution of scattered photons was minimal; and (4) the ratio of the shallow to the deep dose equivalent was nearly unity. Because there are a number of similar irradiators in use, it is hoped that the methodology and results described in this paper will be of use to others. RP MURPHY, MK (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 9 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 JUN PY 1991 VL 60 IS 6 BP 789 EP 796 DI 10.1097/00004032-199106000-00004 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 FN604 UT WOS:A1991FN60400004 PM 2032833 ER PT J AU BECK, HL BOUVILLE, A AF BECK, HL BOUVILLE, A TI USE OF GUMMED-FILM FALLOUT DATA - REPLY SO HEALTH PHYSICS LA English DT Letter C1 NCI, RADIAT EFFECTS BRANCH, BETHESDA, MD 20892 USA. RP BECK, HL (reprint author), US DOE, ENVIRONM MEASUREMENTS LAB, 376 HUDSON ST, NEW YORK, NY 10014 USA. NR 3 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 JUN PY 1991 VL 60 IS 6 BP 863 EP 864 PG 2 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA FN604 UT WOS:A1991FN60400014 ER PT J AU MOORE, R AF MOORE, R TI MANUSCRIPT MANAGER, VERSION 1.2-E SO HEALTH PHYSICS LA English DT Software Review RP MOORE, R (reprint author), IDAHO NATL ENGN LAB, US DOE, ENVIRONM SCI BRANCH, RADIOL & ENVIRONM SCI LAB, IDAHO FALLS, ID 83402 USA. NR 0 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 JUN PY 1991 VL 60 IS 6 BP 865 EP 866 PG 2 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA FN604 UT WOS:A1991FN60400015 ER PT J AU HEPP, GR CONNOLLY, P KENNAMER, RA HARVEY, WF AF HEPP, GR CONNOLLY, P KENNAMER, RA HARVEY, WF TI WOOD DUCK HATCH DATE - RELATIONSHIP TO PAIRING CHRONOLOGY, PLASMA LUTEINIZING-HORMONE, AND STEROID-HORMONES DURING AUTUMN AND WINTER SO HORMONES AND BEHAVIOR LA English DT Article ID MALLARDS ANAS-PLATYRHYNCHOS; ANNUAL REPRODUCTIVE-CYCLE; MALE ZEBRA FINCHES; SEXUAL-BEHAVIOR; 2ND BROODS; NATAL PHILOPATRY; SEASONAL-CHANGES; RHESUS-MONKEY; BLACK DUCKS; MATE CHOICE C1 AUBURN UNIV,ALABAMA AGR EXPT STN,AUBURN,AL 36849. OREGON HLTH SCI UNIV,DEPT PHYSIOL,PORTLAND,OR 97201. SAVANNAH RIVER ECOL LAB,AIKEN,SC 29801. RP HEPP, GR (reprint author), AUBURN UNIV,DEPT ZOOL & WILDLIFE SCI,AUBURN,AL 36849, USA. NR 62 TC 0 Z9 0 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0018-506X J9 HORM BEHAV JI Horm. Behav. PD JUN PY 1991 VL 25 IS 2 BP 242 EP 257 DI 10.1016/0018-506X(91)90054-L PG 16 WC Behavioral Sciences; Endocrinology & Metabolism SC Behavioral Sciences; Endocrinology & Metabolism GA FP176 UT WOS:A1991FP17600010 PM 2066083 ER PT J AU KAKATI, S XIAO, H SIDDIQUI, SY SREEKANTAIAH, C WEIER, HUG GREEN, DM FISHER, JE ALLEN, JE AF KAKATI, S XIAO, H SIDDIQUI, SY SREEKANTAIAH, C WEIER, HUG GREEN, DM FISHER, JE ALLEN, JE TI CONSTITUTIONAL EXTRA CHROMOSOMAL ELEMENT IN A FAMILY WITH WILMS-TUMOR SO HUMAN GENETICS LA English DT Article ID GENE AMPLIFICATION; INTERSTITIAL DELETION; SHORT ARM; ANIRIDIA; CANCER; ASSOCIATION; 11P13; HETEROZYGOSITY; DUPLICATION; MUTATION AB We report the presence of an extra chromosomal element in a family with Wilms' tumor (WT). This family has three children, two of whom were affected. One son, the proband, had bilateral and one daughter had unilateral WT. The first child, the father, and the mother did not have WT. The son with bilateral WT had a ring chromosome (R) both in the lymphocytes as well as in the kidney tissue. The size of the ring varied considerably from cell to cell. The daughter with unilateral WT had an abnormal clone containing a small chromosomal ring (r) in phytohemagglutinin (PHA)-stimulated and Epstein-Barr virus (EBV)-transformed lymphocytes. The mother had a karyotype similar to that of the daughter with WT. We hypothesize that the proband's ring chromosome could be the amplified form of the r inherited from the mother. Chromosome 11 was cytogenetically normal in all the cells examined of the affected children and the unaffected mother. In situ hybridization with a centromere-specific DNA cocktail indicated dispersed centromeric DNA both in r and R. C1 CHILDRENS HOSP BUFFALO,BUFFALO,NY. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP KAKATI, S (reprint author), ROSWELL PK CANC INST,666 ELM ST,BUFFALO,NY 14263, USA. NR 33 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0340-6717 J9 HUM GENET JI Hum. Genet. PD JUN PY 1991 VL 87 IS 2 BP 183 EP 188 DI 10.1007/BF00204178 PG 6 WC Genetics & Heredity SC Genetics & Heredity GA FT647 UT WOS:A1991FT64700017 PM 1648545 ER PT J AU Martens, JS Ginley, DS Beyer, JB Nordman, JE Honenwarter, GKG AF Martens, J. S. Ginley, D. S. Beyer, J. B. Nordman, J. E. Honenwarter, G. K. G. TI A Model and Equivalent Circuit for a Superconducting Flux Flow Transistor SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article AB A three-terminal high-frequency active device made of a single film of a high T, superconductor that is based on the magnetic control of flux flow is presented. The device is composed of parallel weak links with a nearby magnetic control line. A model has been developed that is based on solving the equation of motion of Abrikosov vortices subject to "Lorentz" viscous and pinning forces, as well as magnetic surface barriers. The model has been used to predict device transit time (computed from flux velocity) and device IV curves. The predictions are compared to measured parameters with resulting very good agreement. C1 [Martens, J. S.; Beyer, J. B.; Nordman, J. E.] Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. [Ginley, D. S.] Sandia Natl Labs, Org 1144, Albuquerque, NM 87185 USA. [Honenwarter, G. K. G.] HYPRESS Inc, Elsmford, NY USA. RP Martens, JS (reprint author), Sandia Natl Labs, Org 1144, POB 5800, Albuquerque, NM 87185 USA. FU National Science Foundation; Sandia National Laboratories; Air Force Office of Scientific Research FX This work was supported in part by the National Science Foundation under a Graduate Fellowship, by Sandia National Laboratories, and by the Air Force Office of Scientific Research. NR 20 TC 39 Z9 39 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1051-8223 EI 1558-2515 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1991 VL 1 IS 2 BP 95 EP 101 DI 10.1109/77.84615 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA V30NW UT WOS:000208823700003 ER PT J AU Liou, ML Chen, WH Haskell, BG Kim, DM Lee, H Neuvo, Y Nishitani, T Pirsch, P Rajala, SA Sun, MT Woods, JW Yasuda, Y AF Liou, Ming L. Chen, Wen-hsiung Haskell, Barry G. Kim, Dae M. Lee, Hua Neuvo, Yrjoe Nishitani, Takao Pirsch, Peter Rajala, Sarah A. Sun, Ming-Ting Woods, John W. Yasuda, Yasuhiko TI Untitled SO IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY LA English DT Editorial Material C1 [Chen, Wen-hsiung] Allis Chalmers, Harvey, IL USA. [Chen, Wen-hsiung] Univ So Calif, Dept Elect Engn, Los Angeles, CA 90089 USA. [Chen, Wen-hsiung] CLI, San Jose, CA USA. [Chen, Wen-hsiung] Calif State Univ San Jose, Dept Elect Engn, San Jose, CA USA. [Haskell, Barry G.] Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. [Haskell, Barry G.] AT&T Bell Labs, Holmdel, NJ USA. [Haskell, Barry G.] Rutgers State Univ, Piscataway, NJ 08855 USA. [Haskell, Barry G.] CUNY City Coll, New York, NY USA. [Haskell, Barry G.] Columbia Univ, New York, NY 10027 USA. [Kim, Dae M.] MIT, Cambridge, MA USA. [Kim, Dae M.] Rice Univ, Dept Elect & Comp Engn, Houston, TX 77251 USA. [Kim, Dae M.] Max Planck Inst Solid State Phys, Stuttgart, Germany. [Kim, Dae M.] IBM, Thomas J Watson Res Ctr, Armonk, NY USA. [Kim, Dae M.] Oak Ridge Natl Lab, Oak Ridge, TN USA. [Lee, Hua] Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. [Lee, Hua] Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA. [Neuvo, Yrjoe] Helsinki Univ Technol, FIN-02150 Espoo, Finland. [Neuvo, Yrjoe] Tampere Univ Technol, FIN-33101 Tampere, Finland. [Neuvo, Yrjoe] Acad Finland, Helsinki, Finland. [Neuvo, Yrjoe] Cornell Univ, Ithaca, NY 14853 USA. [Nishitani, Takao] NEC Corp, Kawasaki, Kanagawa, Japan. [Pirsch, Peter] Telefunken, Televis Dept, Hannover, Germany. [Pirsch, Peter] Univ Hannover, Dept Elect Engn, D-30167 Hannover, Germany. [Pirsch, Peter] SEL Res Ctr, Stuttgart, Germany. [Rajala, Sarah A.] N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. [Rajala, Sarah A.] Wake Forest Univ, Bowman Gray Sch Med, Dept Radiol, Winston Salem, NC USA. [Woods, John W.] Rensselaer Polytech Inst, ECSE Dept, Troy, NY USA. [Yasuda, Yasuhiko] Univ Tokyo, IIS, Tokyo 1138654, Japan. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1051-8215 J9 IEEE T CIRC SYST VID JI IEEE Trans. Circuits Syst. Video Technol. PD JUN PY 1991 VL 1 IS 2 BP 169 EP 173 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA V04SC UT WOS:000207077100001 ER PT J AU WEAVER, HT CORBETT, WT PIMBLEY, JM AF WEAVER, HT CORBETT, WT PIMBLEY, JM TI SOFT ERROR PROTECTION USING ASYMMETRIC RESPONSE LATCHES SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Note ID SEU AB A static latch design is analyzed whose single event upset (SEU) sensitivity is extremely dependent on its logic state. A simple "and" gate for two of these asymmetric response latches provides high-speed error correction for a single bit and the combination represents a hardened logic element. C1 RENSSELAER POLYTECH INST,TROY,NY 12180. RP WEAVER, HT (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 10 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 JUN PY 1991 VL 38 IS 6 BP 1555 EP 1557 DI 10.1109/16.81644 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA FL269 UT WOS:A1991FL26900044 ER PT J AU BAUMGART, CW DUNHAM, ME MOSES, JD AF BAUMGART, CW DUNHAM, ME MOSES, JD TI CURVE FITTING AND ERROR MODELING FOR THE DIGITIZATION PROCESS NEAR THE NYQUIST RATE SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB Although sampling principles for waveform digitization are well known, most transient recording practice does not exercise bandwidth exceeding 1/4 Nyquist rate. This practice results from observation of increasing reconstruction error in that regime. In this paper we use model-based parametric estimation (MBPE) techniques to numerically examine the limits of digitization errors. MBPE has proven very successful for the effective bits test of digitizer accuracy, and we show here that it is a strong candidate for reconstruction whenever some a priori information is available. The numerical results aid in the optimum use of modern transient recorders to their full analog bandwidth capability. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV SPACE SCI,LOS ALAMOS,NM 87544. RP BAUMGART, CW (reprint author), EG&G ENERGY MEASUREMENTS INC,LOS ALAMOS OPERAT,LOS ALAMOS,NM 87544, USA. NR 11 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 1991 VL 40 IS 3 BP 553 EP 557 DI 10.1109/19.87018 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA FZ416 UT WOS:A1991FZ41600004 ER PT J AU BENDRIEM, B DEWEY, SL SCHLYER, DJ WOLF, AP VOLKOW, ND AF BENDRIEM, B DEWEY, SL SCHLYER, DJ WOLF, AP VOLKOW, ND TI QUANTITATION OF THE HUMAN BASAL GANGLIA WITH POSITRON EMISSION TOMOGRAPHY - A PHANTOM STUDY OF THE EFFECT OF CONTRAST AND AXIAL POSITIONING SO IEEE TRANSACTIONS ON MEDICAL IMAGING LA English DT Article ID LIVING HUMAN-BRAIN; COMPUTED-TOMOGRAPHY; RECEPTORS; PET; RESOLUTION AB The accurate measurement of the concentration of a radioisotope in small structures with PET requires a correction for quantitation loss due to the partial volume effect and the effect of scattered radiation. To evaluate errors associated with measures in the human basal ganglia (BG) we have built a unilateral model of the BG that we have inserted in a 20 cm cylinder. The recovery coefficient (RC = measured activity/true activity) for our BG phantom has been measured on a CTI tomograph (model 931-08/12) with different background concentrations (contrast) and at different axial locations in the gantry. The BG was visualized on 4 or 5 slices depending on its position in the gantry and on the contrast used. The RC was 0.75 with no background (contrast equal to 1.0). Increasing the relative radioactivity concentration in the background increased the RC from 0.75 to 2.00 when the contrast was -0.7 (BG < Background). The RC was also affected by the size and the shape of the region of interest (ROI) used (RC from 0.75 to 0.67 with ROI size from 0.12 to 1.41 cm2). These results show that accurate RC correction depends not only on the volume of the structure but also on its contrast with its surroundings as well as on the selection of the ROI. They also demonstrate that the higher the contrast the more sensitive to axial positioning PET measurements in the BG are. These data provide us with some information about the variability of PET measurements in small structure like the BG and we have proposed some strategies to improve the reproducibility. C1 BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. BROOKHAVEN NATL LAB, DEPT MED, UPTON, NY 11973 USA. RP CEA, HOP ORSAY, SERV HOSP FREDERIC JOLIOT, F-91406 ORSAY, FRANCE. NR 18 TC 44 Z9 44 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0278-0062 EI 1558-254X J9 IEEE T MED IMAGING JI IEEE Trans. Med. Imaging PD JUN PY 1991 VL 10 IS 2 BP 216 EP 222 DI 10.1109/42.79480 PG 7 WC Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Engineering, Electrical & Electronic; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Computer Science; Engineering; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA FM228 UT WOS:A1991FM22800013 PM 18222819 ER PT J AU ROBISCOE, RT KADISH, A MAIER, WB AF ROBISCOE, RT KADISH, A MAIER, WB TI OVERDAMPED ARC-DISCHARGE DATA AND AN AWA MODEL SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article ID TRANSIENT ELECTRICAL DISCHARGES; LUMPED-CIRCUIT MODEL; DIELECTRIC SURFACES; FUNCTIONAL-BEHAVIOR; RESISTANCE AB We compare experimental data on overdamped arc discharges with a lumped-circuit discharge model employing the Arc Welder's Ansatz (AWA). The AWA prescribes that the arc resistance varies in time as R-alpha (t) = V*/\I(t)\, where V* is a positive constant and I (t) is the discharge current. In the circuit, in addition to the time-dependent arc resistance R-alpha and a small arc inductance L-alpha, there is an external time-dependent series resistance R(o), inductance L(o), and source capacitance C; the values of R(o), L(o), and C are given. We compare the AWA theory with an observed arc current pulse I (t) by using the given values of R(o), L(o), and C and normalizing the theory to one point on the data curve; an adequate fit to the data is obtained. We also compare data for the dynamic arc resistance R-alpha (t) with the AWA prescription and with other available theories for R-alpha, which also use a one-point normalization. The AWA form for R-alpha compares favorably with the other theories. Next, we show that many theories for the arc resistance near threshold (where the current I --> 0+ as t --> 0+) can be reduced to the form R-alpha is-proportional-to 1/I(P), p > 0, and we argue that for proper threshold behavior, one must have p = 1. The AWA theory meets this criterion; most other theories do not. Although all theories of R-alpha are subject to questions regarding the onset of the arc, we conclude that our AWA theory-in its present form-accounts for overdamped arc discharge data after onset at least as well as other existing theories. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV SPACE SCI & TECHNOL,LOS ALAMOS,NM 87545. RP ROBISCOE, RT (reprint author), MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717, USA. NR 15 TC 13 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD JUN PY 1991 VL 19 IS 3 BP 529 EP 534 DI 10.1109/27.87234 PG 6 WC Physics, Fluids & Plasmas SC Physics GA FX319 UT WOS:A1991FX31900007 ER PT J AU SHARIT, J MALON, DM AF SHARIT, J MALON, DM TI INCORPORATING THE EFFECTS OF TIME-ESTIMATION INTO HUMAN-RELIABILITY ANALYSIS FOR HIGH-RISK SITUATIONS SO IEEE TRANSACTIONS ON RELIABILITY LA English DT Article DE HUMAN RELIABILITY; TIME ESTIMATION; HUMAN-SYSTEM INTERACTION; HUMAN INFORMATION PROCESSING AB This paper provides a modeling framework for predicting the effects of discrepancies between subjective and objective measures of elapsed time on performance of human-machine interaction tasks in high-risk situations. Following a review of the major theories and experimental research findings in time estimation, the importance of time estimation in terms of its potential for affecting human performance in critical human-machine system operations is discussed. The formulations are primarily motivated by limitations in existing methods of human-reliability analysis that adjust human-error probabilities, often severely, on the basis of stress inferred from the ratio of estimated time available for task completion to time required. Our approach for dealing with time-related task demands is to describe the ongoing dynamic processes during task performance that are associated with temporal estimation, and to assess their effects on human reliability. This is accomplished through a conceptual framework that is depicted and discussed in terms of several task features and information-processing mechanisms, and that implicitly recognizes the experimental evidence concerning human time-estimation performance. This concept is illustrated through special cases that are formulated and analyzed in terms of their potential for contributing to human error as a function of time-estimation considerations. C1 ARGONNE NATL LAB,DIV COMP & TELECOMMUN,ARGONNE,IL 60439. RP SHARIT, J (reprint author), SUNY BUFFALO,DEPT IND ENGN,BUFFALO,NY 14260, USA. NR 20 TC 1 Z9 1 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9529 J9 IEEE T RELIAB JI IEEE Trans. Reliab. PD JUN PY 1991 VL 40 IS 2 BP 247 EP 254 DI 10.1109/24.87137 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA FT312 UT WOS:A1991FT31200025 ER PT J AU COSTIN, LS CHEN, EP AF COSTIN, LS CHEN, EP TI A THERMOMECHANICAL ANALYSIS OF THE G-TUNNEL HEATED BLOCK EXPERIMENT USING A COMPLIANT-JOINT ROCK-MASS MODEL SO INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS LA English DT Article AB The results of two-dimensional finite element analyses of several thermal/mechanical loading cycles of the G-Tunnel heated block experiment are presented. The deformations of the block resulting from thermal loading under constant biaxial stress were determined using a recently developed compliant-joint rock-mass model. The results of the finite element calculations were compared to experimental results reported by Zimmerman et al. Qualitative agreements between the experimental and numerical results were obtained in all cases while quantitative agreements were achieved in some cases. The results of this evaluation are discussed. C1 SANDIA NATL LABS,DIV APPL MECH 3,ALBUQUERQUE,NM 87185. RP COSTIN, LS (reprint author), SANDIA NATL LABS,DIV GEOTECH DESIGN,ALBUQUERQUE,NM 87185, USA. NR 15 TC 1 Z9 1 U1 3 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0363-9061 J9 INT J NUMER ANAL MET JI Int. J. Numer. Anal. Methods Geomech. PD JUN PY 1991 VL 15 IS 6 BP 379 EP 398 DI 10.1002/nag.1610150603 PG 20 WC Engineering, Geological; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA FT559 UT WOS:A1991FT55900001 ER PT J AU Abraham, R Keith, A Koebbe, M Mayer-Kress, G AF Abraham, Ralph Keith, Alexander Koebbe, Matthew Mayer-Kress, Gottfried TI COMPUTATIONAL UNFOLDING OF DOUBLE-CUSP MODELS OF OPINION FORMATION SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article AB In 1975, Isnard and Zeeman proposed a cusp catastrophe model for the polarization of a social group, such as the population of a democratic nation. Ten years later, Kadyrov combined two of these cusps into a model for the opinion dynamics of two "nonsocialist" nations. This is a nongradient dynamical system, more general than the double-cusp catastrophe studied by Callahan and Sashin [1987]. Here, we present a computational study of the nongradient double cusp, in which the degeneracy of Kadyrov's model is unfolded in codimension eight. Also, we develop a discrete-time cusp model, study the corresponding double cusp, establish its equivalence to the continuous-time double cusp, and discuss some potential applications. We find bifurcations for multiple critical-point attractors, periodic attractors, and (for the discrete case) bifurcations to quasiperiodic and chaotic attractors. C1 [Abraham, Ralph; Keith, Alexander; Koebbe, Matthew; Mayer-Kress, Gottfried] Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. [Mayer-Kress, Gottfried] Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Abraham, R (reprint author), Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. FU University of California INCOR program FX It is a pleasure to acknowledge the generosity of Peter Brecke, James Keeler, Judy Challinger, Yoshi Oono, and Christopher Zeeman in sharing their ideas and resources. Timothy Poston has been most helpful in explaining the technicalities of topological and differentiable unfoldings, and we are grateful to him. The phase portraits of Fig. 2 were made with software developed with the support of the U.S. Department of Energy's Applied Mathematical Sciences program at Brookhaven National Laboratory. Finally, we thank the University of California INCOR program, administered through the Center for Nonlinear Systems, Los Alamos National Laboratory, and its director, David Campbell, for the support which made this joint project possible. The numerical work was done in the Computational Mathematics Laboratory at the University of California at Santa Cruz, on a ring of Silicon Graphics Iris workstations, one loaned by Silicon Graphics Inc., through the good graces of Peter Broadwell, and one generously provided by Maria Schonbek. NR 26 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-1274 EI 1793-6551 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD JUN PY 1991 VL 1 IS 2 BP 417 EP 430 DI 10.1142/S0218127491000324 PG 14 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA V44LM UT WOS:000209750500013 ER PT J AU COHEN, ML AF COHEN, ML TI EXPERIMENTAL CONSTRAINTS ON BOSON-EXCHANGE MECHANISMS FOR HIGH-TC SUPERCONDUCTORS SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT WORKSHOP ON PHYSICS AND MATHEMATICS OF ANYONS CY FEB 01-02, 1991 CL HOUSTON, TX SP UNIV HOUSTON, TEXAS CTR SUPERCONDUCT AB At this point there is no consensus on which of the proposed theories best explains the properties of the high T(c) oxides. In addition to anyon theories, there are variations on the more conventional boson-exchange pairing mechanisms which have been suggested. Analyses of experimental data such as the isotope effect, gap to T(c) ratio, and heat capacity discontinuity at T(c) put constraints on the applicability of these theories and limit the number of acceptable proposals. RP COHEN, ML (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT PHYS,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 0 TC 4 Z9 4 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD JUN PY 1991 VL 5 IS 10 BP 1495 EP 1505 DI 10.1142/S0217979291001425 PG 11 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA FX393 UT WOS:A1991FX39300003 ER PT J AU Barnes, T AF Barnes, T. TI THE 2D HEISENBERG ANTIFERROMAGNET IN HIGH-Tic SUPERCONDUCTIVITY A Review of Numerical Techniques and Results SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article AB In this article we review numerical studies of the quantum Heisenberg antiferromagnet on a square lattice, which is a model of the magnetic properties of the undoped "precursor insulators" of the high temperature superconductors. We begin with a brief pedagogical introduction and then discuss zero and nonzero temperature properties and compare the numerical results to analytical calculations and to experiment where appropriate. We also review the various algorithms used to obtain these results, and discuss algorithm developments and improvements in computer technology which would be most useful for future numerical work in this area. Finally we list several outstanding problems which may merit further investigation. C1 [Barnes, T.] Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. [Barnes, T.] Oak Ridge Natl Lab, Ctr Computationally Intens Phys, Oak Ridge, TN 37831 USA. [Barnes, T.] Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Barnes, T (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. FU United States Department of Energy under Martin Marietta Energy Systems Inc. [DE-AC05-840R21400]; United States Department of Energy under Physics Department of the University of Tennessee [DE-AS05-76ER03956]; United States Department of Energy under Caltech Concurrent Computation Program [DE-FG03-85ER25009]; State of Tennessee Science Alliance Center [R01-1061-68] FX A complete list of persons who have been of assistance in the compilation of this review would be long indeed, so I will simply acknowledge those who have contributed directly to the text at my request, through discussions of important points or by providing written material; these include D. P. Arovas, W. J. L. Buyers, J. Carlson, E. Dagotto, D. C. Johnston, M. D. Kovarik, S. Liang, J. W. Lynn, J. W. Negele, E. Sanchez-Velasco, B. Statt, E. S. Swanson, A.-M. Tremblay, and N. Trivedi. I would also like to acknowledge the Physics Department of the University of Tennessee at Knoxville, the Science Alliance Center of the State of Tennessee, the Physics Division of Oak Ridge National Laboratory, the Physics Department of the University of Toronto, and G. C. Fox and the participants in the Caltech Concurrent Computation Program for their support of various aspects of this work. This research was supported in part by the United States Department of Energy under contracts DE-AC05-840R21400 with Martin Marietta Energy Systems Inc., DE-AS05-76ER03956 with the Physics Department of the University of Tennessee, DE-FG03-85ER25009 with the Caltech Concurrent Computation Program and by the State of Tennessee Science Alliance Center under contract R01-1061-68. NR 150 TC 77 Z9 77 U1 1 U2 5 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0129-1831 EI 1793-6586 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD JUN PY 1991 VL 2 IS 2 DI 10.1142/50129183191000949 PG 51 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA V33NJ UT WOS:000209025200006 ER PT J AU SCHWARTZ, JL MUSTAFI, R BECKETT, MA CZYZEWSKI, EA FARHANGI, E GRDINA, DJ ROTMENSCH, J WEICHSELBAUM, RR AF SCHWARTZ, JL MUSTAFI, R BECKETT, MA CZYZEWSKI, EA FARHANGI, E GRDINA, DJ ROTMENSCH, J WEICHSELBAUM, RR TI RADIATION-INDUCED DNA DOUBLE-STRAND BREAK FREQUENCIES IN HUMAN SQUAMOUS-CELL CARCINOMA CELL-LINES OF DIFFERENT RADIATION SENSITIVITIES SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID NEUTRAL FILTER ELUTION; SYNCHRONOUS CHO-CELLS; HUMAN-TUMOR CELLS; X-IRRADIATION; DOSE-RESPONSE; IONIZING-RADIATION; MAMMALIAN-CELLS; REPAIR; CYCLE; INDUCTION AB DNA neutral (pH 9.6) filter elution was used to measure radiation-induced DNA double-strand break (dsb) frequencies in eight human squamous cell carcinoma cell lines with radiosensitivities (D0) ranging from 1.07 to 2.66 Gy and DBAR values ranging from 1.46 to 4.08 Gy. The elution profiles of unirradiated samples from more radiosensitive cell lines were all steeper in slope than the profiles from resistant cells. The shapes of the dsb induction curves were curvilinear and there was some variability from cell line to cell line in the dose-response for the induction of DNA dsb after exposures to 5-100 Gy Co-60-gamma-rays. There was no relation between the shapes of the survival curves and the shapes of the dose-responses for the induction of DNA dsb. At low doses (5-25 Gy), three out of four of the more sensitive cell lines (DBAR < 2.5 Gy) had larger initial break frequencies than the more resistant lines (DBAR > 3.0 Gy). Although the low-dose (5-25 Gy) elution results were variable, they do suggest that DNA neutral elution will detect differences between sensitive and resistant tumour cells in initial DNA dsb frequencies. C1 UNIV CHICAGO,DEPT RADIAT & CELLULAR ONCOL,CHICAGO,IL 60637. UNIV CHICAGO,DEPT OBSTET & GYNECOL,CHICAGO,IL 60637. RP SCHWARTZ, JL (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,9700 S CASS AVE,BLDG 202,ARGONNE,IL 60439, USA. FU NCI NIH HHS [CA 37435, CA 42596] NR 30 TC 51 Z9 51 U1 0 U2 1 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 JUN PY 1991 VL 59 IS 6 BP 1341 EP 1352 DI 10.1080/09553009114551211 PG 12 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 FZ396 UT WOS:A1991FZ39600004 PM 1677380 ER PT J AU BARRETT, C BOBROWICZ, F BRICKNER, RG CLARK, BA GUPTA, R HAYES, AH TREASE, H WHITE, AB AF BARRETT, C BOBROWICZ, F BRICKNER, RG CLARK, BA GUPTA, R HAYES, AH TREASE, H WHITE, AB TI SUPERCOMPUTING AT LOS-ALAMOS-NATIONAL-LABORATORY SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article RP BARRETT, C (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SUM PY 1991 VL 5 IS 2 BP 3 EP 9 DI 10.1177/109434209100500201 PG 7 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA FR919 UT WOS:A1991FR91900001 ER PT J AU HEATH, MT GEIST, GA DRAKE, JB AF HEATH, MT GEIST, GA DRAKE, JB TI EARLY EXPERIENCE WITH THE INTEL IPSC/860 AT OAK-RIDGE-NATIONAL-LABORATORY SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Article ID 3D AB This report summarizes the early experience in using the Intel iPSC/860 parallel supercomputer at Oak Ridge National Laboratory. The hardware and software are described in some detail, and the machine's performance is studied using both simple computational kernels and a number of complete applications programs. C1 OAK RIDGE NATL LAB,MAT SCI SECT,COMP SCI GRP,OAK RIDGE,TN 37831. RP HEATH, MT (reprint author), OAK RIDGE NATL LAB,MAT SCI SECT,RES STAFF,OAK RIDGE,TN 37831, USA. NR 21 TC 3 Z9 3 U1 0 U2 0 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SUM PY 1991 VL 5 IS 2 BP 10 EP 26 DI 10.1177/109434209100500202 PG 17 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA FR919 UT WOS:A1991FR91900002 ER PT J AU HIRST, E AF HIRST, E TI ELECTRIFYING IMPROVEMENTS SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Editorial Material RP HIRST, E (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37830, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SUM PY 1991 VL 7 IS 4 BP 6 EP 7 PG 2 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FW308 UT WOS:A1991FW30800002 ER PT J AU BROLIN, EC AF BROLIN, EC TI ELECTRIFYING IMPROVEMENTS SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Editorial Material RP BROLIN, EC (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SUM PY 1991 VL 7 IS 4 BP 8 EP 8 PG 1 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FW308 UT WOS:A1991FW30800004 ER PT J AU LEDERMAN, LM AF LEDERMAN, LM TI SCIENTISTS AS LEADERS SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Editorial Material RP LEDERMAN, LM (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SUM PY 1991 VL 7 IS 4 BP 30 EP 30 PG 1 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FW308 UT WOS:A1991FW30800038 ER PT J AU CANAVAN, GH AF CANAVAN, GH TI WHAT NEXT FOR NASA SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Editorial Material RP CANAVAN, GH (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SUM PY 1991 VL 7 IS 4 BP 35 EP 36 PG 2 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA FW308 UT WOS:A1991FW30800049 ER PT J AU HANSEN, ADA KAPUSTIN, VN POLISSAR, AD AF HANSEN, ADA KAPUSTIN, VN POLISSAR, AD TI MEASUREMENTS OF CARBONACEOUS AEROSOLS IN THE EASTERN ARCTIC SO IZVESTIYA AKADEMII NAUK SSSR FIZIKA ATMOSFERY I OKEANA LA Russian DT Article ID PARTICLES; SOOT AB From Macrh 27 to May 21, 1989 atmospheric aerosol samples were collected at the Polar Station on Wrangel Island in the Eastern Soviet Arctic (70-degrees 58' N, 178-degrees 33' W). The samples were then analysed by an optical transmission technique to determine the concentration of aerosol soot near the surface. Although many samples show evidence of contamination from local combustion sources, 20 samples are believed to represent the background Arctic air. Aerosol soot concentrations deduced from these samples ranged from 10 to 100 nanograms per cubic meter, values that are comparable with those measured in the Alaskan and Canadian Arctic. An intercomparison of the results of the analysis of the samples in laboratories in the USA and USSR show excellent agreement. C1 ACAD SCI USSR,INST ATMOSPHER PHYS,MOSCOW V-71,USSR. RP HANSEN, ADA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0002-3515 J9 IZV AN SSSR FIZ ATM+ PD JUN PY 1991 VL 27 IS 6 BP 614 EP 620 PG 7 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA GK085 UT WOS:A1991GK08500002 ER PT J AU SUNWOO, AJ HAYASHIGATANI, H MORRIS, JW LUCEY, GK AF SUNWOO, AJ HAYASHIGATANI, H MORRIS, JW LUCEY, GK TI THE EFFECT OF PRETINNING ON THE SOLDERABILITY OF COPPER SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article AB The reliability and integrity of pretinned, copper-clad printed circuit boards are serious concerns in the manufacture of electronic devices. The nature of wetting during the soldering of copper is critical in the reliability of these solder joints. Some preliminary experiments on the solderability of pretinned copper suggest that pretinning with a lead-rich solder, such as 95Pb-5Sn is preferred to pretinning with a eutectic solder, because the latter can develop exposed intermetallics during aging or baking that wet poorly. RP SUNWOO, AJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD JUN PY 1991 VL 43 IS 6 BP 21 EP 24 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA FT201 UT WOS:A1991FT20100006 ER PT J AU ROMERO, C AF ROMERO, C TI MOLECULAR-DYNAMICS APPLIED TO THE STUDY OF THE HYDRATION SHELLS OF THE HYDRATED ELECTRON AND THE CL- AND LI+ IONS SO JOURNAL DE CHIMIE PHYSIQUE ET DE PHYSICO-CHIMIE BIOLOGIQUE LA French DT Article ID OPTICAL-ABSORPTION SPECTRUM; INTEGRAL MONTE-CARLO; EXCESS ELECTRONS; ENERGY SURFACE; WATER MOLECULE; SIMPLE FLUIDS; SIMULATION; SOLVATION; COMPLEXES; FIELD AB The structures of the hydration shells of the ions Li+ and Cl- and of the hydrated electron have been studied using molecular dynamics simulations in conjunction with the Feynman path integral method. The results show that the quantum fluctuations of the excess electron in water cause principally fluctuations in the radius of the cavity trapping the electron. On the other hand, it has been found that the orientation of the molecules of water in the electric field of the electron is as large as that found in the hydration shells of Cl-. C1 UNIV CHILE,FAC CIENCIAS FIS & MATEMAT,DEPT FIS,SANTIAGO,CHILE. RP ROMERO, C (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 21 TC 5 Z9 5 U1 0 U2 1 PU EDITIONS SCIENTIFIQUES ELSEVIER PI PARIS CEDEX 15 PA 141 RUE JAVEL, 75747 PARIS CEDEX 15, FRANCE SN 0021-7689 J9 J CHIM PHYS PCB JI J. Chim. Phys.-Chim. Biol. PD JUN PY 1991 VL 88 IS 6 BP 765 EP 777 PG 13 WC Biochemistry & Molecular Biology; Chemistry, Physical SC Biochemistry & Molecular Biology; Chemistry GA GG248 UT WOS:A1991GG24800010 ER PT J AU YOO, MH FU, CL LEE, JK AF YOO, MH FU, CL LEE, JK TI DEFORMATION TWINNING IN METALS AND ORDERED INTERMETALLICS-TI AND TI-ALUMINIDES SO JOURNAL DE PHYSIQUE III LA English DT Article ID POSITIVE TEMPERATURE-DEPENDENCE; ELEVATED-TEMPERATURES; PLASTIC-DEFORMATION; YIELD STRESS; HCP METALS; SUPERLATTICE STRUCTURES; SINGLE-CRYSTALS; COMPOUND; FRACTURE; ALLOYS AB The role of deformation twinning in the strength and ductility of metals and ordered intermetallic alloys is examined on the basis of crystallography, energetics and kinetics of deformation twinning. A systematic analysis is made by taking Ti, Ti3Al, TiAl, and Al3Ti as four model systems. In comparison with profuse twinning in Ti, the intrinsic difficulty of twinning in Ti3Al is rationalized in terms of the interchange shuffling mechanism. A fault (SISF) dragging mechanism based on the interaction torque explains the physical source for the low mobility of screw superdislocations in TiAl, which may lead to (111) [112BAR] twin nucleation. In TiAl and Al3Ti alloys, the twin-slip (ordinary) conjugate relationship makes an important contribution to the strain compatibility for high-temperature plasticity. Potentially beneficial alloying additions to promote twinning are discussed. C1 MICHIGAN TECHNOL UNIV,DEPT MET & MAT ENGN,HOUGHTON,MI 49931. RP YOO, MH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 80 TC 40 Z9 41 U1 1 U2 9 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 1155-4320 J9 J PHYS III JI J. Phys. III PD JUN PY 1991 VL 1 IS 6 BP 1065 EP 1084 PG 20 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Fluids & Plasmas SC Materials Science; Physics GA FP510 UT WOS:A1991FP51000016 ER PT J AU HUMPHREYS, CJ MAHER, DM EAGLESHAM, DJ KVAM, EP SALISBURY, IG AF HUMPHREYS, CJ MAHER, DM EAGLESHAM, DJ KVAM, EP SALISBURY, IG TI THE ORIGIN OF DISLOCATIONS IN MULTILAYERS SO JOURNAL DE PHYSIQUE III LA English DT Article ID MISFIT DISLOCATIONS; EPITAXY; THICKNESS; DEFECTS; SILICON; LAYERS AB This paper will consider some fundamental questions concerning the source, nucleation and propagation of dislocations in multilayers, particularly semiconductor epilayers. The concept of a << critical thickness >> for the introduction of misfit dislocations in a strained layer will be considered, and X-ray topography and electron microscopy results will be presented which demonstrate that the concept of a critical thickness is not as well defined as previously supposed. Theoretical considerations for the source of misfit dislocations in epilayers grown on dislocation free substrates indicate that surface sources are improbable in low mismatched systems at typical growth temperatures, however the experimental evidence is that the nucleation of misfit dislocations is relatively easy. A new regenerative source with unique properties has been identified in the GeSi/Si system and we have called this source the diamond defect because of its diamond shape (it is a four-sided planar fault on a {111} plane with [110] sides so that two opposing internal angles are 60-degrees and the other two are 120-degrees). This defect operates like a Frank-Read source, but it has the unique property that it can repetitively produce dislocations with two different Burgers vectors on the same glide plane, and it can generate orthogonal bundles of misfit dislocations. Whether this source exists more widely in other materials systems requires further assessment. The important role of misfit dislocations in trace impurity gettering is demonstrated. C1 N CAROLINA STATE UNIV,DEPT MAT SCI & ENGN,RALEIGH,NC 27695. AT&T BELL LABS,MURRAY HILL,NJ 07974. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP HUMPHREYS, CJ (reprint author), UNIV CAMBRIDGE,DEPT MAT SCI & MET,PEMBROKE ST,CAMBRIDGE CB2 3QZ,ENGLAND. RI Kvam, Eric/A-2457-2010 NR 24 TC 13 Z9 13 U1 0 U2 8 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 1155-4320 J9 J PHYS III JI J. Phys. III PD JUN PY 1991 VL 1 IS 6 BP 1119 EP 1130 PG 12 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Fluids & Plasmas SC Materials Science; Physics GA FP510 UT WOS:A1991FP51000019 ER PT J AU SHIRAISHI, K TAKAKU, Y YOSHIMIZU, K IGARASHI, Y MASUDA, K MCINROY, JF TANAKA, G AF SHIRAISHI, K TAKAKU, Y YOSHIMIZU, K IGARASHI, Y MASUDA, K MCINROY, JF TANAKA, G TI DETERMINATION OF THORIUM AND URANIUM IN TOTAL DIET SAMPLES BY INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article DE THORIUM DETERMINATION; URANIUM DETERMINATION; DIETARY INTAKE; INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY; MATRIX EFFECT ID INTERNAL STANDARDIZATION; MATRIX INTERFERENCES; ELEMENTS; ICP AB The Th and U contents in total diet samples were determined by inductively coupled plasma mass spectrometry (ICP-MS). The internal standardization method was adopted to compensate for non-spectral interferences arising from matrix elements in the sample solutions. Concentration levels of the order of pg ml-1 of Th and U in the total diet sample were determined easily and rapidly by using Bi as an internal standard. The mean concentrations and standard deviations of Th and U in the total diet samples were found to be 25 +/- 12 and 44 +/- 20 ng g-1 of ash, respectively (for n = 62). C1 MARUBUN CO,CHUO KU,TOKYO 103,JAPAN. JAPAN CHEM ANAL CTR,CHIBA 281,JAPAN. UNIV CALIF LOS ALAMOS SCI LAB,HLTH & ENVIRONM CHEM GRP,LOS ALAMOS,NM 87545. RP SHIRAISHI, K (reprint author), NATL INST RADIOL SCI,DIV RADIOECOL,3609 ISOZAKI,NAKAMINATO,IBARAKI 31112,JAPAN. OI igarashi, yasuhito/0000-0002-6396-788X NR 15 TC 20 Z9 20 U1 0 U2 0 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0267-9477 J9 J ANAL ATOM SPECTROM JI J. Anal. At. Spectrom. PD JUN PY 1991 VL 6 IS 4 BP 335 EP 338 DI 10.1039/ja9910600335 PG 4 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA FN654 UT WOS:A1991FN65400016 ER PT J AU LUK, VK AMOS, DE AF LUK, VK AMOS, DE TI DYNAMIC CYLINDRICAL CAVITY EXPANSION OF COMPRESSIBLE STRAIN-HARDENING MATERIALS SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article ID PENETRATION AB We developed models for the dynamic expansion of cylindrical cavities from zero initial radii for compressible, elastic-plastic, rate-independent materials with power-law strain-hardening. Results from cavity-expansion models were used to derive perforation models to predict residual velocities and ballistic limits for rigid, conical-nose projectiles perforating strain-hardening target plates. We compared the numerical results from models for incompressible and compressible materials to show the effect of compressibility. To verify the models, we also compared the model predictions of residual velocities and ballistic limits with the data from terminal-ballistic experiments with tungsten projectiles impacting 5083-H131 aluminum armor plates at normal incidence. Very good agreement was obtained for impact velocities between 200 and 1,200 m/s and 12.7, 50.8, and 76.2-mm thick targets. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 17 TC 9 Z9 21 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD JUN PY 1991 VL 58 IS 2 BP 334 EP 340 DI 10.1115/1.2897190 PG 7 WC Mechanics SC Mechanics GA HP716 UT WOS:A1991HP71600005 ER PT J AU WARREN, WE KRAYNIK, AM AF WARREN, WE KRAYNIK, AM TI THE NONLINEAR ELASTIC BEHAVIOR OF OPEN-CELL FOAMS SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article ID MECHANICS AB A constitutive model for the nonlinear elastic behavior of isotropic low-density open-cell foams with three-dimensional structure is formulated in terms of a strain energy function. The theory is based on micromechanical analysis of an idealized tetrahedral unit cell of arbitrary orientation that contains four half-struts joining at equal angles. The force-displacement relations for each strut are expressed by compliances for bending and stretching that do not depend on the magnitude of applied force. Contributions to the strain energy from large deformation effects are assumed to depend on strut reorientation and stretching, and are determined by analyzing a pin-jointed structure. The analysis is considered to be valid for finite strains below the onset of yielding associated with strut buckling. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 16 TC 45 Z9 48 U1 0 U2 9 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD JUN PY 1991 VL 58 IS 2 BP 376 EP 381 DI 10.1115/1.2897196 PG 6 WC Mechanics SC Mechanics GA HP716 UT WOS:A1991HP71600011 ER PT J AU WILDE, EW BENEMANN, JR WEISSMAN, JC TILLETT, DM AF WILDE, EW BENEMANN, JR WEISSMAN, JC TILLETT, DM TI CULTIVATION OF ALGAE AND NUTRIENT REMOVAL IN A WASTE HEAT UTILIZATION PROCESS SO JOURNAL OF APPLIED PHYCOLOGY LA English DT Article DE ALGAE; MICROALGAE; WASTE HEAT; ALGAL CULTIVATION ID BIOMASS AB A process providing a beneficial use for waste heat and excess nutrients in the cooling waters of nuclear reactors and fossil-fueled power generating plants has been developed. The process involves the cultivation of selected strains of thermotolerant microalgae in heated discharge waters and the subsequent harvesting of the algal biomass for nutrient removal, recovery of energy and fertilizer, and extraction of high value products. The design of such a process is presented for a large cooling reservoir receiving a discharge of 10(9) 1-1 d-1 of secondary cooling water containing 100-mu-g 1-1 of available P and 400-mu-g 1-1 of available N. Based on this nutrient load, with a 1% P content in the algal biomass and a productivity of 10 g m-2 d-1, a 100 ha region would be needed for the process. Hydraulic barriers (submerged plastic curtains) would isolate the 100 ha algal production area "cultivation zone" in the influent end of the reservoir to create a hydraulic and thermal environment conductive to the selective growth of filamentous, thermotolerant, nitrogen-fixing, blue-green algae. The algal culture would be inoculated into the thermal plume and harvested near the distal barrier of the cultivation zone with rotating, backwashed, fine mesh screens ("microstrainers"). A portion of the harvested biomass would be recycled to the inoculation site to maintain a dense culture. This process could mitigate both thermal and nutrient loadings on receiving bodies of water. C1 MICROBIAL PROD INC,VERO BEACH,FL 32962. RP WILDE, EW (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER SITE,AIKEN,SC 29808, USA. NR 33 TC 17 Z9 18 U1 2 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0921-8971 J9 J APPL PHYCOL JI J. Appl. Phycol. PD JUN PY 1991 VL 3 IS 2 BP 159 EP 167 DI 10.1007/BF00003698 PG 9 WC Biotechnology & Applied Microbiology; Marine & Freshwater Biology SC Biotechnology & Applied Microbiology; Marine & Freshwater Biology GA GB554 UT WOS:A1991GB55400009 ER PT J AU MARIELLA, RP LEHEW, S GUTHREAU, W AF MARIELLA, RP LEHEW, S GUTHREAU, W TI THE INFLUENCE OF THE INDIUM INCORPORATION RATE ON THE LASING WAVELENGTH OF INGAAS LASERS GROWN BY MOLECULAR-BEAM EPITAXY SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID QUANTUM-WELL LASERS; THRESHOLD CURRENT-DENSITY; SURFACE-STRUCTURE; GAAS; INDEX; TEMPERATURE; EFFICIENCY; DEPENDENCE; ALGAAS; GALLIUM AB Lasing wavelengths have been measured from 871 to 966 nm for a series of graded-index separate-confinement-heterostructure lasers with single InGaAs strained-layer quantum wells which were grown by molecular beam epitaxy (MBE). These wavelength data are compared to the corresponding indium fluxes in order to determine the incorporation rate of indium as a function of the substrate temperature during the growths. Kinetic models based on a simple sticking coefficient or based on the Law of Mass Action can fit these data for MBE growth with substrate temperatures of 570 or 625-degrees-C. RP MARIELLA, RP (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,MS L-228,LIVERMORE,CA 94550, USA. NR 33 TC 0 Z9 0 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 JUN 1 PY 1991 VL 69 IS 11 BP 7435 EP 7439 DI 10.1063/1.347558 PG 5 WC Physics, Applied SC Physics GA FP401 UT WOS:A1991FP40100008 ER PT J AU ROMERO, LA AF ROMERO, LA TI THE STABILITY OF STRETCHING AND ACCELERATING PLASTIC SHEETS .1. SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INSTABILITY; JET AB The equations governing the linearized stability of a perfectly plastic sheet that is isotropically stretching in the horizontal direction and accelerating in the vertical direction are derived. The equations are analyzed for the case where the vertical acceleration is zero. The stability of the sheet depends on a dimensionless parameter-GAMMA that measures the ratio of the inertial forces to the plastic forces. This parameter decreases as the sheet stretches. The sheet is stable provided-GAMMA is large. When GAMMA is small, the sheet is unstable to symmetrical disturbances. There is no sharply defined most unstable wavelength, but the most unstable wavelengths range between 10 and 1/GAMMA-times the thickness of the sheet. RP ROMERO, LA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 9 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 JUN 1 PY 1991 VL 69 IS 11 BP 7474 EP 7486 DI 10.1063/1.347564 PG 13 WC Physics, Applied SC Physics GA FP401 UT WOS:A1991FP40100014 ER PT J AU ROMERO, LA AF ROMERO, LA TI THE STABILITY OF STRETCHING AND ACCELERATING PLASTIC SHEETS .2. SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The equations governing the linearized stability of a perfectly plastic sheet that is isotropically stretching in the horizontal direction and accelerating in the vertical direction are analyzed. The stability of the sheet depends on two dimensionless parameters. The parameter-GAMMA measures the ratio of the inertial forces to the plastic forces, and the parameter-PI measures the importance of the pressure gradient induced by the stretching to the pressure gradient induced by the vertical acceleration. Both of these parameters decrease as the sheet stretches. When PI is small and GAMMA/PI is not, the sheet breaks up because of Rayleigh-Taylor instability. When both PI and GAMMA/PI are small, the sheet breaks up to the necking instability. The case where PI is large has already been covered in part I of this paper. RP ROMERO, LA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1991 VL 69 IS 11 BP 7487 EP 7499 DI 10.1063/1.347565 PG 13 WC Physics, Applied SC Physics GA FP401 UT WOS:A1991FP40100015 ER PT J AU JELLISON, GE AF JELLISON, GE TI EXAMINATION OF THIN SIO2-FILMS ON SI USING SPECTROSCOPIC POLARIZATION MODULATION ELLIPSOMETRY SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THERMALLY GROWN OXIDE; SILICON DIOXIDE; STRESS MEASUREMENTS; INTERFACE; OXIDATION AB A series of SiO2 films with thicknesses varying from 3 to 325 nm have been grown on silicon using standard dry oxygen growth techniques and examined using the two-channel polarization modulation ellipsometer, which has increased sensitivity for very thin insulating films on silicon. Using a biased estimator fitting technique, the ellipsometric data are fit to either an air-SiO2-Si model or an air-SiO2-interface-Si model, where the optical functions of the SiO2 layer are approximated using an isotropic one-term Sellmeier approximation. The results from the one-term Sellmeier approximation show that the refractive index of the SiO2 layer increases with decreasing film thickness, while the interfacial layer thickness decreases with decreasing film thickness. RP JELLISON, GE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 32 TC 70 Z9 70 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1991 VL 69 IS 11 BP 7627 EP 7634 DI 10.1063/1.347532 PG 8 WC Physics, Applied SC Physics GA FP401 UT WOS:A1991FP40100034 ER PT J AU ZINKOWSKI, RP MEYNE, J BRINKLEY, BR AF ZINKOWSKI, RP MEYNE, J BRINKLEY, BR TI THE CENTROMERE KINETOCHORE COMPLEX - A REPEAT SUBUNIT MODEL SO JOURNAL OF CELL BIOLOGY LA English DT Article ID ALPHA-SATELLITE DNA; NEWT LUNG-CELLS; MAMMALIAN KINETOCHORE; CHROMOSOME ATTACHMENT; CYTOPLASMIC DYNEIN; INDIAN MUNTJAC; CENP-B; MICROTUBULE; MITOSIS; MOVEMENT AB The three-dimensional structure of the kinetochore and the DNA/protein composition of the centromere-kinetochore region was investigated using two novel techniques, caffeine-induced detachment of unreplicated kinetochores and stretching of kinetochores by hypotonic and/or shear forces generated in a cytocentrifuge. Kinetochore detachment was confirmed by EM and immunostaining with CREST autoantibodies. Electron microscopic analyses of serial sections demonstrated that detached kinetochores represented fragments derived from whole kinetochores. This was especially evident for the seven large kinetochores in the male Indian muntjac that gave rise to 80-100 fragments upon detachment. The kinetochore fragments, all of which interacted with spindle microtubules and progressed through the entire repertoire of mitotic movements, provide evidence for a subunit organization within the kinetochore. Further support for a repeat subunit model was obtained by stretching or uncoiling the metaphase centromere-kinetochore complex by hypotonic treatments. When immunostained with CREST autoantibodies and subsequently processed for in situ hybridization using synthetic centromere probes, stretched kinetochores displayed a linear array of fluorescent subunits arranged in a repetitive pattern along a centromeric DNA fiber. In addition to CREST antigens, each repetitive subunit was found to bind tubulin and contain cytoplasmic dynein, a microtubule motor localized in the zone of the corona. Collectively, the data suggest that the kinetochore, a plate-like structure seen by EM on many eukaryotic chromosomes is formed by the folding of a linear DNA fiber consisting of tandemly repeated subunits interspersed by DNA linkers. This model, unlike any previously proposed, can account for the structural and evolutional diversity of the kinetochore and its relationship to the centromere of eukaryotic chromosomes of many species. C1 UNIV CALIF LOS ALAMOS SCI LAB,GENET GRP,LOS ALAMOS,NM 87545. RP ZINKOWSKI, RP (reprint author), UNIV ALABAMA,DEPT CELL BIOL,BIRMINGHAM,AL 35294, USA. FU NCI NIH HHS [CA 41424] NR 63 TC 212 Z9 217 U1 0 U2 3 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 222 E 70TH STREET, NEW YORK, NY 10021 SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD JUN PY 1991 VL 113 IS 5 BP 1091 EP 1110 DI 10.1083/jcb.113.5.1091 PG 20 WC Cell Biology SC Cell Biology GA FN341 UT WOS:A1991FN34100011 PM 1828250 ER PT J AU BARTHOLDI, MF AF BARTHOLDI, MF TI NUCLEAR-DISTRIBUTION OF CENTROMERES DURING THE CELL-CYCLE OF HUMAN-DIPLOID FIBROBLASTS SO JOURNAL OF CELL SCIENCE LA English DT Article DE CENTROMERES; FIBROBLASTS; NUCLEAR DISTRIBUTION; CELL CYCLE ID HUMAN-CHROMOSOMES; HUMAN AUTOANTIBODIES; INTERPHASE NUCLEI; CENP-B; SCLERODERMA; LOCALIZATION; KINETOCHORE; HYBRIDIZATION; MICROSCOPY; PROTEINS AB The distribution of centromeres in the interphase nuclei of human diploid fibroblasts was analyzed using anti-centromere immunofluorescence and laser scanning confocal microscopy. The positions of the centromeres were placed within the nuclear chromatin distribution and presented some aspects of the dynamics of nuclear structure during the cell cycle. During the G1 phase of the cell cycle many of the centromeres were located in association with nucleoli or fused in chromocenters. A few centromeres were dispersed singly in the euchromatin. During S phase, the fused centromeres dispersed, often forming distinct patterns of rings or lines. At prophase, the centromere immunofluorescence condensed into distinct double dots upon the formation of the prophase chromosomes. Quantitative analysis by both image and flow cytometry showed that the intensity of immunofluorescence started to duplicate in mid S phase, well before the appearance of the double dots. The coalesence of the centromeres during G1 indicated that regions of the chromosome domains remain compacted and possibly sequestered from transcriptional activity. During S phase the chromatin and the coalesced centromeres dispersed for DNA replication. The dynamics of the centromeres and chromatin during the cell cycle seen here are evidence for a higher-order organization of nuclear structure that accompanies DNA transcription and replication. RP BARTHOLDI, MF (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CELLULAR & MOLEC BIOL GRP,MAIL STOP M888,LOS ALAMOS,NM 87545, USA. NR 24 TC 54 Z9 54 U1 0 U2 0 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE, CAMBS, ENGLAND CB4 4DL SN 0021-9533 J9 J CELL SCI JI J. Cell Sci. PD JUN PY 1991 VL 99 BP 255 EP 263 PN 2 PG 9 WC Cell Biology SC Cell Biology GA FT526 UT WOS:A1991FT52600007 PM 1885670 ER PT J AU AGGELER, J WARD, J BLACKIE, LM BARCELLOSHOFF, MH STREULI, CH BISSELL, MJ AF AGGELER, J WARD, J BLACKIE, LM BARCELLOSHOFF, MH STREULI, CH BISSELL, MJ TI CYTODIFFERENTIATION OF MOUSE MAMMARY EPITHELIAL-CELLS CULTURED ON A RECONSTITUTED BASEMENT-MEMBRANE REVEALS STRIKING SIMILARITIES TO DEVELOPMENT INVIVO SO JOURNAL OF CELL SCIENCE LA English DT Article DE INSITU HYBRIDIZATION; CASEIN MICELLES; MILK FAT GLOBULE; BETA-CASEIN; BASEMENT MEMBRANE ID GENE-EXPRESSION; EXTRACELLULAR-MATRIX; FUNCTIONAL-DIFFERENTIATION; MORPHOGENESIS; COMPONENTS; SECRETION; PROTEIN; GLAND; SERUM; MILK AB In the present study we provide evidence that the cytodifferentiation of primary mouse mammary epithelial cells within the alveolar-like structures formed after culture on a reconstituted basement membrane resembles development in vivo during late pregnancy and early lactation. During the first two days in culture on a basement membrane gel in the presence of lactogenic hormones, epithelial cells isolated from mid-pregnant mice are disorganized and central lumina are largely absent. Levels of mRNA for the milk proteins, beta-casein and transferrin, are dramatically reduced. By the second or third day in culture, cytoplasmic polarization becomes evident and prominent apical junctional complexes are formed. Synthesis of both mRNA and milk protein is reinitiated at this time. By day 4, well-defined lumina appear, and abundant synthesis and secretion of casein and lipid is observed. A striking feature of this differentiation in culture is the specific localization of milk protein gene expression (beta-casein mRNA) to luminal epithelial cells in the alveolar-like structures. At the ultrastructural level, increased milk protein synthesis and secretion are paralleled by a fourfold increase in rough ER that resembles the dramatic increase in the ER observed in vivo following parturition. One indication of tissue-specific differentiation observed in later cultures (days 4-11) is the synthesis and secretion of abundant casein micelles. A second characteristic of lactating mammary epithelial cells in vivo that has not previously been observed in culture is the secretion of milk fat globules. Taken together, these observations indicate that mammary epithelial cells plated onto a reconstituted basement membrane differentiate to the lactating phenotype in culture. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,BERKELEY,CA 94720. UNIV CALIF DAVIS,SCH MED,DEPT CELL BIOL & HUMAN ANAT,DAVIS,CA 95616. NR 36 TC 100 Z9 101 U1 0 U2 0 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE, CAMBS, ENGLAND CB4 4DL SN 0021-9533 J9 J CELL SCI JI J. Cell Sci. PD JUN PY 1991 VL 99 BP 407 EP & PN 2 PG 0 WC Cell Biology SC Cell Biology GA FT526 UT WOS:A1991FT52600021 PM 1885677 ER PT J AU LYNCH, GC STECKLER, R SCHWENKE, DW VARANDAS, AJC TRUHLAR, DG GARRETT, BC AF LYNCH, GC STECKLER, R SCHWENKE, DW VARANDAS, AJC TRUHLAR, DG GARRETT, BC TI USE OF SCALED EXTERNAL CORRELATION, A DOUBLE MANY-BODY EXPANSION, AND VARIATIONAL TRANSITION-STATE THEORY TO CALIBRATE A POTENTIAL-ENERGY SURFACE FOR FH2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Review ID LONG-RANGE INTERACTION; QUANTUM SCATTERING CALCULATIONS; INCLUDING ELECTRON CORRELATION; ABSOLUTE RATE CONSTANTS; SADDLE-POINT VICINITY; FLUORINE-ATOMS; F+H2 REACTION; EXCHANGE-REACTIONS; CROSS-SECTIONS; INTERACTION COEFFICIENTS AB A new potential energy surface is presented for the reaction F + H-2 --> HF + H. The regions of the surface corresponding to collinear and bent geometries in the F-H-H and H-F-H barrier regions are based on scaled external correlation (SEC) electronic structure calculations, and the F-H...H exit channel region is based on the previously developed surface No. 5. The functional form of the new surface includes dispersion forces by a double many-body expansion (DMBE), and the surface was adjusted so that the van der Waals well in the F...H-H region agrees with available experimental predictions. We have calculated stationary point properties for the new surface as well as product-valley barrier maxima of vibrationally adiabatic potential curves for F + H-2 --> HF(upsilon' = 3) + H,F + HD --> HF (upsilon' = 3) + D, and F + D2 --> DF (upsilon' = 4) + D. The new surface should prove useful for studying the effect on dynamics of a low, early barrier with a wide, flat bend potential, as indicated by the best available electronic structure calculations. C1 UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. RP UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. RI Garrett, Bruce/F-8516-2011; Varandas, Antonio/E-1846-2012; schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Varandas, Antonio/0000-0003-1501-3317; Truhlar, Donald/0000-0002-7742-7294 NR 115 TC 95 Z9 95 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1991 VL 94 IS 11 BP 7136 EP 7149 DI 10.1063/1.460197 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FL837 UT WOS:A1991FL83700020 ER PT J AU CURTISS, LA RAGHAVACHARI, K TRUCKS, GW POPLE, JA AF CURTISS, LA RAGHAVACHARI, K TRUCKS, GW POPLE, JA TI GAUSSIAN-2 THEORY FOR MOLECULAR-ENERGIES OF 1ST-ROW AND 2ND-ROW COMPOUNDS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BOND-DISSOCIATION ENERGY; ACETYLENE; ETHYLENE; STRENGTHS; ABINITIO; SYSTEMS; ALKALI AB The Gaussian-2 theoretical procedure (G2 theory), based on ab initio molecular orbital theory, for calculation of molecular energies (atomization energies, ionization potentials, electron affinities, and proton affinities) of compounds containing first- (Li-F) and second-row atoms (Na-Cl) is presented. This new theoretical procedure adds three features to G1 theory [J. Chem. Phys. 90, 5622 (1989)] including a correction for nonadditivity of diffuse-sp and 2df basis set extensions, a basis set extension containing a third d function on nonhydrogen atoms and a second p function on hydrogen atoms, and a modification of the higher level correction. G2 theory is a significant improvement over G1 theory because it eliminates a number of deficiencies present in G1 theory. Of particular importance is the improvement in atomization energies of ionic molecules such as LiF and hydrides such as C2H6, NH3, N2H4, H2O2, and CH3SH. The average absolute deviation from experiment of atomization energies of 39 first-row compounds is reduced from 1.42 to 0.92 kcal/mol. In addition, G2 theory gives improved performance for hypervalent species and electron affinities of second-row species (the average deviation from experiment of electron affinities of second-row species is reduced from 1.94 to 1.08 kcal/mol). Finally, G2 atomization energies for another 43 molecules, not previously studied with G1 theory, many of which have uncertain experimental data, are presented and differences with experiment are assessed. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. CARNEGIE MELLON UNIV,DEPT CHEM,PITTSBURGH,PA 15213. RP CURTISS, LA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,DIV CHEM TECHNOL,ARGONNE,IL 60439, USA. NR 29 TC 3163 Z9 3181 U1 9 U2 112 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 JUN 1 PY 1991 VL 94 IS 11 BP 7221 EP 7230 DI 10.1063/1.460205 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FL837 UT WOS:A1991FL83700029 ER PT J AU REDDY, NRS SMALL, GJ AF REDDY, NRS SMALL, GJ TI HOLE BURNING AS A PROBE OF EXCITON BANDWIDTHS IN AMORPHOUS SOLIDS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID RESOLUTION OPTICAL-SPECTRA; ANTENNA COMPLEX; RHODOPSEUDOMONAS-SPHAEROIDES; PHOTOSYNTHETIC BACTERIA; PIGMENT ORGANIZATION; BURNED SPECTRA; BACTERIOCHLOROPHYLL; SPECTROSCOPY; SCATTERING; PROTEINS C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP REDDY, NRS (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 21 TC 21 Z9 21 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1991 VL 94 IS 11 BP 7545 EP 7546 DI 10.1063/1.460186 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FL837 UT WOS:A1991FL83700063 ER PT J AU SHAW, MS AF SHAW, MS TI MONTE-CARLO SIMULATION OF EQUILIBRIUM CHEMICAL-COMPOSITION OF MOLECULAR FLUID MIXTURES IN THE NATOMS PT ENSEMBLE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID DILUTION ACTIVITY-COEFFICIENTS; COMPUTER-SIMULATION; PARTIAL ENTHALPIES RP SHAW, MS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,GRP T-14,MAIL STOP B214,LOS ALAMOS,NM 87545, USA. NR 13 TC 26 Z9 28 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1991 VL 94 IS 11 BP 7550 EP 7553 DI 10.1063/1.460188 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FL837 UT WOS:A1991FL83700065 ER PT J AU LAFEMINA, JP SCHENTER, GK AF LAFEMINA, JP SCHENTER, GK TI TWISTED INTRAMOLECULAR CHARGE-TRANSFER AND THE TORSIONAL POTENTIAL FUNCTION OF DIMETHYLAMINOBENZONITRILE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID ELECTRON-TRANSFER; STATE; 4-DIMETHYLAMINOBENZONITRILE RP LAFEMINA, JP (reprint author), PACIFIC NW LAB, MOLEC SCI RES CTR, POB 999, RICHLAND, WA 99352 USA. RI Schenter, Gregory/I-7655-2014 OI Schenter, Gregory/0000-0001-5444-5484 NR 14 TC 8 Z9 8 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 JUN 1 PY 1991 VL 94 IS 11 BP 7558 EP 7559 DI 10.1063/1.460190 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA FL837 UT WOS:A1991FL83700067 ER PT J AU MARSHALL, WL SIMONSON, JM AF MARSHALL, WL SIMONSON, JM TI THE (LIQUID + VAPOR) CRITICAL-TEMPERATURE CURVE FOR (XD2O + (1-X)H2O) SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article ID TEMPERATURES; H2O RP MARSHALL, WL (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 7 TC 10 Z9 10 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD JUN PY 1991 VL 23 IS 6 BP 613 EP 616 DI 10.1016/S0021-9614(05)80104-1 PG 4 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA FQ436 UT WOS:A1991FQ43600012 ER PT J AU KENIK, EA AF KENIK, EA TI LOSS OF GRAIN-BOUNDARY SEGREGANT DURING ION MILLING SO JOURNAL OF ELECTRON MICROSCOPY TECHNIQUE LA English DT Article DE SEGREGATION; X-RAY MICROANALYSIS; EDXS; EDS; ARTIFACT; SPECIMEN HEATING ID EQUILIBRIUM SEGREGATION AB It is shown that material segregated to grain boundaries can be lost during ion milling. This specimen preparation artifact has been studied in the case of bismuth in copper and has also been observed for phosphorus in stainless steel. The loss is associated with specimen heating during ion milling and can be alleviated by good clamping and cooling of the specimen during milling. Specimen heating permits grain boundary diffusion of the segregating element to the specimen surfaces with subsequent loss of segregant from the specimen by evaporation or sputtering during ion milling. Loss of bismuth during in situ heating to 200-300-degrees-C is demonstrated. Therefore, care must be taken in specimen preparation for analytical electron microscopy measurement of such segregation. Similar effects may occur during ion milling of other materials, especially those where low thermal conductivity will result in high beam heating. In these cases, care must be taken to avoid loss of segregant during specimen preparation. Additional tests showed that no significant loss of segregant was observed during X-ray microanalysis, even at nominal room temperature and probe currents five-fold higher than that normally used for microanalysis. RP KENIK, EA (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,BLDG 5500,MS-6376,POB 2008,OAK RIDGE,TN 37831, USA. NR 13 TC 4 Z9 4 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0741-0581 J9 J ELECTRON MICR TECH PD JUN PY 1991 VL 18 IS 2 BP 167 EP 171 DI 10.1002/jemt.1060180211 PG 5 WC Biology; Microscopy SC Life Sciences & Biomedicine - Other Topics; Microscopy GA FL186 UT WOS:A1991FL18600010 PM 1885999 ER PT J AU WOODS, PS LEDBETTER, MC TEMPEL, N AF WOODS, PS LEDBETTER, MC TEMPEL, N TI PRESERVATION OF EDTA-EXPANDED GRID-MOUNTED CHROMOSOMES AND NUCLEI FOR ELECTRON-MICROSCOPY USING A SPECIALLY DESIGNED FREEZE-DRYER SO JOURNAL OF ELECTRON MICROSCOPY TECHNIQUE LA English DT Article DE WHOLE-MOUNTS; FREEZE-DRY; FREEZE-SUBSTITUTION; TEM ID BIOLOGICAL TISSUES AB We describe methods for freezing and drying EDTA-expanded, fixed metaphase chromosomes and nuclei, attached to grids as whole-mounts, for transmission electron microscopy. These methods use a special apparatus that is simple to construct. While separate freezers and dryers are commercially available, one for freezing blocks of tissue by slamming them against a cold metal surface, and the other for vacuum drying the frozen tissue, our apparatus is designed for gentler, cryogenic liquid plunge freezing and drying, sequentially, in the same apparatus, thus avoiding any compression or damage to the specimen. Use of a cryoprotectant is not essential; however, good results are obtained more often when 20% ethanol is used. Freezing is accomplished by rapid propulsion of the grid, with specimens attached, into slushy N2 (-210-degrees-C) within the drying chamber; drying is automatic, by either sublimation under vacuum or by solvent substitution using absolute ethanol followed by acetone, which, in turn, is removed with a critical-point dryer. The apparatus offers a means of drying chromosomes and nuclei in an expanded state, and avoids the shrinkage of these structures that occurs during stepwise passage through increasing concentrations of ethanol or acetone. RP WOODS, PS (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. NR 20 TC 2 Z9 2 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0741-0581 J9 J ELECTRON MICR TECH PD JUN PY 1991 VL 18 IS 2 BP 183 EP 191 DI 10.1002/jemt.1060180214 PG 9 WC Biology; Microscopy SC Life Sciences & Biomedicine - Other Topics; Microscopy GA FL186 UT WOS:A1991FL18600013 PM 1909358 ER PT J AU MOON, TJ HUA, TQ WALKER, JS AF MOON, TJ HUA, TQ WALKER, JS TI LIQUID-METAL FLOW IN A BACKWARD ELBOW IN THE PLANE OF A STRONG MAGNETIC-FIELD SO JOURNAL OF FLUID MECHANICS LA English DT Article ID VARIABLE-AREA DUCTS; THIN CONDUCTING WALLS; HIGH HARTMANN NUMBER; RECTANGULAR DUCTS; MAGNETOHYDRODYNAMIC FLOWS AB This paper treats a liquid-metal flow through a sharp elbow connecting two constant-area, rectangular ducts with thin metal walls. There is a uniform, strong magnetic field in the plane of the ducts' centrelines, and the velocity component normal to the magnetic field is in opposite directions upstream and downstream of the elbow. The magnetic field is sufficiently strong that inertial effects are negligible everywhere and viscous effects are confined to boundary layers and to an interior layer lying along the magnetic field lines through the inside corner of the elbow. The interior layer involves large velocities parallel to the magnetic field and carries roughly half of the flow between the upstream and downstream ducts for the case considered. C1 ARGONNE NATL LAB,DIV ENGN PHYS,ARGONNE,IL 60439. UNIV ILLINOIS,DEPT MECH & IND ENGN,URBANA,IL 61801. RP MOON, TJ (reprint author), UNIV TEXAS,DEPT MECH ENGN,AUSTIN,TX 78712, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 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 JUN PY 1991 VL 227 BP 273 EP 292 DI 10.1017/S0022112091000113 PG 20 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA FU275 UT WOS:A1991FU27500011 ER PT J AU HOLM, DD AF HOLM, DD TI ELLIPTIC VORTICES AND INTEGRABLE HAMILTONIAN-DYNAMICS OF THE ROTATING SHALLOW-WATER EQUATIONS SO JOURNAL OF FLUID MECHANICS LA English DT Article AB The problem of the dynamics of elliptical-vortex solutions of the rotating shallow-water equations is solved in Lagrangian coordinates using methods of Hamiltonian mechanics. All such solutions are shown to be quasi-periodic by reducing the problem to quadratures in terms of physically meaningful variables. All of the relative equilibria - including the well-known rodon solution - are shown to be orbitally Lyapunov stable to perturbations in the class of elliptical-vortex solutions. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP HOLM, DD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,MS B284,LOS ALAMOS,NM 87545, USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 24 TC 20 Z9 20 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUN PY 1991 VL 227 BP 393 EP 406 DI 10.1017/S0022112091000162 PG 14 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA FU275 UT WOS:A1991FU27500016 ER PT J AU XU, ZY SHEN, JX WAN, CW LI, CM MUSSEN, P CAO, ZF AF XU, ZY SHEN, JX WAN, CW LI, CM MUSSEN, P CAO, ZF TI FAMILY SOCIALIZATION AND CHILDRENS BEHAVIOR AND PERSONALITY-DEVELOPMENT IN CHINA SO JOURNAL OF GENETIC PSYCHOLOGY LA English DT Article C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,INST HUMAN DEV,TOLMAN HALL,BERKELEY,CA 94720. NE NORMAL UNIV,CHANGCHUN,PEOPLES R CHINA. BEIJING UNIV,BEIJING,PEOPLES R CHINA. NR 9 TC 7 Z9 7 U1 1 U2 3 PU HELDREF PUBLICATIONS PI WASHINGTON PA 1319 EIGHTEENTH ST NW, WASHINGTON, DC 20036-1802 SN 0022-1325 J9 J GENET PSYCHOL JI J. Genet. Psychol. PD JUN PY 1991 VL 152 IS 2 BP 239 EP 253 PG 15 WC Psychology, Developmental; Psychology; Psychology, Multidisciplinary SC Psychology GA FX889 UT WOS:A1991FX88900009 ER PT J AU MILLER, RH GOMBOSI, TI GARY, SP WINSKE, D AF MILLER, RH GOMBOSI, TI GARY, SP WINSKE, D TI THE DIRECTIONAL DEPENDENCE OF MAGNETIC FLUCTUATIONS GENERATED BY COMETARY ION PICKUP SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LOW-FREQUENCY WAVES; SOLAR-WIND INTERACTION; WATER-GROUP IONS; GIACOBINI-ZINNER; ELECTROMAGNETIC-WAVES; COMPUTER-SIMULATIONS; ACCELERATION PROCESSES; HYDROMAGNETIC-WAVES; BEAM INSTABILITIES; FIELD OBSERVATIONS AB The properties of low frequency magnetic fluctuations generated by cometary ion pickup are examined by means of one-dimensional hybrid simulations, in which newborn ions are created at a constant rate. The helicity and direction of propagation of magnetic fluctuations are investigated for various cometary ion injection angles, alpha, relative to the solar wind magnetic field. The parameter eta represents the relative contribution of wave energy density propagating in the direction away from the comet, parallel to the beam. For small (quasi-parallel) injection angles, alpha approximately 0-degrees and eta is of order unity, while for larger (quasi-perpendicular) angles, alpha approximately 90-degrees and eta is about 0.5. At intermediate angles, alpha approximately 60-degrees, eta can vary between 0 and 1, depending on the wave number. The wave properties are consistent with the instabilities (right-hand cyclotron resonant modes at small alpha, left-hand Alfven/ion cyclotron modes at large a) expected from linear theory. Consequences of these results for particle acceleration are also discussed. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV SPACE & SCI TECHNOL,LOS ALAMOS,NM 87544. UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87544. RP MILLER, RH (reprint author), UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES LAB,ANN ARBOR,MI 48109, USA. RI Gombosi, Tamas/G-4238-2011 OI Gombosi, Tamas/0000-0001-9360-4951 NR 57 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1991 VL 96 IS A6 BP 9479 EP 9490 DI 10.1029/91JA00158 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FV651 UT WOS:A1991FV65100008 ER PT J AU DETMAN, TR DRYER, M YEH, T HAN, SM WU, ST MCCOMAS, DJ AF DETMAN, TR DRYER, M YEH, T HAN, SM WU, ST MCCOMAS, DJ TI A TIME-DEPENDENT, 3-DIMENSIONAL MHD NUMERICAL STUDY OF INTERPLANETARY MAGNETIC DRAPING AROUND PLASMOIDS IN THE SOLAR-WIND SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CORONAL MASS EJECTA; CLOUDS; EVENTS; TRANSIENTS; FIELDS; BURST AB A spherical plasmoid is injected into a representative solar wind at 18 solar radii, which is chosen as the lower computational boundary of a 3-dimensional MHD model. The field line topology of the injected plasmoid resembles the streamline topology of a spherical vortex. Evolution of the plasmoid and its surrounding interplanetary medium is described out to approximately 1 AU for three cases with different velocities imparted to the plasmoid. In the first case a plasmoid enters the lower boundary with a velocity of 250 km s-1 equal to the steady state background solar wind velocity at the lower boundary. In the second and third cases the plasmoid enters with peak velocities of twice and 3 times the background velocity. A number of interesting features are found. For instance, the evolving plasmoid retains its basic magnetic topology although the shape becomes distorted. As might be expected, the shape distortion increases with the injection velocity. Development of a bow shock occurs when the plasmoid is injected with a velocity greater than the sum of the local fast magnetosonic speed and the ambient solar wind velocity. The MHD simulation demonstrates magnetic draping around the plasmoid. C1 TENNESSEE TECHNOL UNIV,DEPT MECH ENGN,COOKEVILLE,TN 38505. UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,HUNTSVILLE,AL 35899. UNIV ALABAMA,DEPT MECH ENGN,HUNTSVILLE,AL 35899. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP DETMAN, TR (reprint author), NOAA,ENVIRONM RES LABS,SPACE ENVIRONM LAB,R-E-SE,325 BROADWAY,BOULDER,CO 80303, USA. NR 29 TC 70 Z9 70 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1991 VL 96 IS A6 BP 9531 EP 9540 DI 10.1029/91JA00443 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FV651 UT WOS:A1991FV65100012 ER PT J AU FUSELIER, SA LENNARTSSON, OW THOMSEN, MF RUSSELL, CT AF FUSELIER, SA LENNARTSSON, OW THOMSEN, MF RUSSELL, CT TI HE-2+ HEATING AT A QUASI-PARALLEL SHOCK SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID BOW SHOCK; ION REFLECTION; MAGNETOSHEATH; ISEE-1 AB We present the first observations of solar wind He-2+ heating downstream from the Earth's quasi-parallel shock. These observations show that in conjunction with protons, two different regions are observed. In regions where the proton distribution is cooler, more dense, and similar to that observed downstream from quasi-perpendicular shocks, the He-2+ distributions is shell-like, also similar to that observed downstream from quasi-perpendicular shocks. In regions where the proton distribution is hotter, less dense, and Maxwellianlike, the He-2+ distribution is also Maxwellianlike without evidence for a shell. These observations support the interpretation that the nearly isotropic proton and He-2+ distributions are produced through the strong interaction of a very dense specularly reflected proton beam with the incident solar wind, while the cooler proton distributions and shell-like He-2+ distributions are produced in a manner similar to that at the quasi-perpendicular bow shock. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP FUSELIER, SA (reprint author), LOCKHEED MISSILES & SPACE CO INC,PALO ALTO RES LAB,DEPT 91-20,BLDG 255,3251 HANOVER ST,PALO ALTO,CA 94304, USA. OI Russell, Christopher/0000-0003-1639-8298 NR 21 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1991 VL 96 IS A6 BP 9805 EP 9810 DI 10.1029/91JA00380 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FV651 UT WOS:A1991FV65100034 ER PT J AU PLUMMER, MV AF PLUMMER, MV TI PATTERNS OF FECES PRODUCTION IN FREE-LIVING GREEN SNAKES, OPHEODRYS-AESTIVUS SO JOURNAL OF HERPETOLOGY LA English DT Note ID FOOD-HABITS; CONSUMPTION; MOVEMENTS; ECOLOGY; CYCLES; DIET RP PLUMMER, MV (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. NR 27 TC 3 Z9 3 U1 0 U2 4 PU SOC STUD AMPHIBIANS REPTILES PI OXFORD PA DEPT OF ZOOLOGY MIAMI UNIV, OXFORD, OH 45056 SN 0022-1511 J9 J HERPETOL JI J. Herpetol. PD JUN PY 1991 VL 25 IS 2 BP 222 EP 226 DI 10.2307/1564656 PG 5 WC Zoology SC Zoology GA FQ099 UT WOS:A1991FQ09900018 ER PT J AU FISCHER, RU MAZZOTTI, FJ CONGDON, JD GATTEN, RE AF FISCHER, RU MAZZOTTI, FJ CONGDON, JD GATTEN, RE TI POSTHATCHING YOLK RESERVES - PARENTAL INVESTMENT IN AMERICAN ALLIGATORS FROM LOUISIANA SO JOURNAL OF HERPETOLOGY LA English DT Note ID POSTHATCHING YOLK; CLUTCH SIZE; COMPONENTS; FITNESS; TURTLES; ENERGY C1 UNIV FLORIDA,DEPT WILDLIFE & RANGE SCI,DAVIE,FL 33314. UNIV N CAROLINA,DEPT BIOL,GREENSBORO,NC 27412. RP FISCHER, RU (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29801, USA. NR 23 TC 21 Z9 22 U1 0 U2 2 PU SOC STUD AMPHIBIANS REPTILES PI OXFORD PA DEPT OF ZOOLOGY MIAMI UNIV, OXFORD, OH 45056 SN 0022-1511 J9 J HERPETOL JI J. Herpetol. PD JUN PY 1991 VL 25 IS 2 BP 253 EP 256 DI 10.2307/1564668 PG 4 WC Zoology SC Zoology GA FQ099 UT WOS:A1991FQ09900030 ER PT J AU BARRASH, W RALSTON, DR AF BARRASH, W RALSTON, DR TI ANALYTICAL MODELING OF A FRACTURE-ZONE IN THE BRULE FORMATION AS AN AQUIFER RECEIVING LEAKAGE FROM WATER-TABLE AND ELASTIC AQUITARDS SO JOURNAL OF HYDROLOGY LA English DT Article AB Hydrostratigraphic data define a subhorizontal, laterally limited, highly permeable zone of intensely fractured siltstone (major fracture zone) within the relatively impermeable Brule Formation at a site in Cheyenne County, Nebraska. Two types of transient hydraulic responses were noted in 11 observation wells during an eight-day aquifer test: Type 1 responses occurred in wells which intercepted the major fracture zone; Type 2 responses occurred in wells outside the major fracture zone. Transient responses in Type 1 observation wells are matched with type curves for a three-layered system with a water-table aquitard above an aquifer (major fracture zone) which overlies an elastic aquitard. Because the aquifer is laterally limited and the Brule Formation beyond the major fracture zone has finite hydraulic conductivity, real late-time behavior falls between type curves for an infinite aquifer and for an aquifer with an impermeable boundary at reasonable distances from the pumping well. Aquifer and aquitard parameters determined from curve matches with both limiting boundary conditions are identical for inner-ring observation wells, and nearly so for middle-ring observation wells. Outer-ring observation wells exhibited Type 2 responses which were used only to identify the extent of the major fracture zone. C1 UNIV IDAHO,DEPT GEOL & GEOL ENGN,MOSCOW,ID 83843. RP BARRASH, W (reprint author), IDAHO DEPT HLTH & WELFARE,IDAHO NUCL ENGN LAB,OVERSIGHT PROGRAM,1410 N HILTON RD,BOISE,ID 83706, 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 0022-1694 J9 J HYDROL JI J. Hydrol. PD JUN PY 1991 VL 125 IS 1-2 BP 1 EP 24 DI 10.1016/0022-1694(91)90080-2 PG 24 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA FR898 UT WOS:A1991FR89800001 ER PT J AU MUSLINER, TA LONG, MD FORTE, TM KRAUSS, RM AF MUSLINER, TA LONG, MD FORTE, TM KRAUSS, RM TI SIZE TRANSFORMATIONS OF INTERMEDIATE AND LOW-DENSITY LIPOPROTEINS INDUCED BY UNESTERIFIED FATTY-ACIDS SO JOURNAL OF LIPID RESEARCH LA English DT Article DE APOA-I; FATTY ACIDS; HDL; IDL; LDL; VLDL; LIPOPROTEIN HETEROGENEITY; LIPOLYSIS ID GRADIENT GEL-ELECTROPHORESIS; ELECTRON-MICROSCOPE; PLASMA; LIPASE; CHYLOMICRONS; LIPOLYSIS; SUBFRACTIONATION; TRIGLYCERIDE; METABOLISM; PRODUCTS AB Plasma from individual human subjects is known to contain multiple discrete subpopulations of low (LDL) and intermediate (IDL) density lipoproteins that differ in particle size and density. The metabolic origins of these subpopulations are unknown. Transformation of IDL and larger LDL to smaller, denser LDL particles has been postulated to occur as a result of the combined effects of triglyceride hydrolysis and lipid transfer. However, the presence of multiple small LDL subspecies has been described in patients lacking cholesteryl ester transfer protein. We have characterized an alternative pathway in which size decrements in IDL or LDL are produced in the presence of unesterified fatty acids and a source of apolipoprotein (apo) A-I. Incubation of IDL or LDL subfractions with palmitic acid and either high density lipoproteins (HDL), apoHDL, or purified apoA-I gives rise to apoA-I, apoB-containing complexes that can dissociate into two particles, an apoB-containing lipoprotein with particle diameter 10-30 angstrom smaller than the starting material, and a still smaller species (apparent peak particle diameter 140-190 angstrom) containing lipid and apoA-I but no apoB. The newly formed IDL or LDL are depleted in phospholipid and free cholesterol with no change in apoB-100 as assessed by SDS gel electrophoresis. We hypothesize that this reaction may contribute to the formation of discrete IDL and LDL subpopulations of varying size during the course of hydrolysis of triglyceride-rich lipoproteins in plasma. RP MUSLINER, TA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DONNER LAB,DIV RES MED & RADIAT BIOPHYS,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL-18574] NR 37 TC 9 Z9 9 U1 0 U2 0 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD JUN PY 1991 VL 32 IS 6 BP 903 EP 915 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FU142 UT WOS:A1991FU14200003 PM 1940623 ER PT J AU MUSLINER, TA LONG, MD FORTE, TM NICHOLS, AV GONG, EL BLANCHE, PJ KRAUSS, RM AF MUSLINER, TA LONG, MD FORTE, TM NICHOLS, AV GONG, EL BLANCHE, PJ KRAUSS, RM TI DISSOCIATION OF HIGH-DENSITY-LIPOPROTEIN PRECURSORS FROM APOLIPOPROTEIN-B-CONTAINING LIPOPROTEINS IN THE PRESENCE OF UNESTERIFIED FATTY-ACIDS AND A SOURCE OF APOLIPOPROTEIN-A-I SO JOURNAL OF LIPID RESEARCH LA English DT Article DE HDL; IDL; LDL; VLDL; LIPOPROTEIN HETEROGENEITY; LIPID TRANSFER; LIPOLYSIS ID ESTER TRANSFER PROTEIN; GRADIENT GEL-ELECTROPHORESIS; HUMAN-PLASMA; CHOLESTEROL ACYLTRANSFERASE; ELECTRON-MICROSCOPE; RICH LIPOPROTEINS; INVITRO FORMATION; LIPASE; LIPOLYSIS; CHYLOMICRONS AB Incubation of low (LDL), intermediate (IDL), or very low density lipoproteins (VLDL) with palmitic acid and either high density lipoproteins (HDL), delipidated HDL, or purified apolipoprotein (apo) A-I resulted in the formation of lipoprotein particles with discoidal structure and mean particle diameters ranging from 146 to 254 angstrom by electron microscopy. Discs produced from IDL or LDL averaged 26% protein, 42% phospholipid, 5% cholesteryl esters, 24% free cholesterol, and 3% triglycerides; preparations derived from VLDL contained up to 21% triglycerides. ApoA-I was the predominant protein present, with smaller amounts of apoA-II. Crosslinking studies of discs derived from LDL or IDL indicated the presence of four apoA-I molecules per particle, while those derived from large VLDL varied more in size and contained as many as six apoA-I molecules per particle. Incubation of discs derived from IDL or LDL with purified lecithin:cholesterol acyltransferase (LCAT), albumin, and a source of free cholesterol produced core-containing particles with size and composition similar to HDL2b. VLDL-derived discs behaved similarly, although the HDL products were somewhat larger and more variable in size. When discs were incubated with plasma d > 1.21 g/ml fraction rather than LCAT, core-containing particles in the size range of normal HDL2a and HDL3a were also produced. A variety of other purified free fatty acids were shown to promote disc formation. In addition, some mono and polyunsaturated fatty acids facilitated the formation of smaller, spherical particles in the size range of HDL3c. Both discoidal and small spherical apoA-I-containing lipoproteins were generated when native VLDL was incubated with lipoprotein lipase in the presence of delipidated HDL. We conclude that lipolysis product-mediated dissociation of lipid-apoA-I complexes from VLDL, IDL, or LDL may be a mechanism for formation of HDL subclasses during lipolysis, and that the availability of different lipids may influence the type of HDL-precursors formed by this mechanism. RP MUSLINER, TA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DONNER LAB,DIV RES MED & RADIAT BIOPHYS,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL-18574] NR 53 TC 33 Z9 33 U1 0 U2 1 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD JUN PY 1991 VL 32 IS 6 BP 917 EP 933 PG 17 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FU142 UT WOS:A1991FU14200004 PM 1940624 ER PT J AU YETHIRAJ, M YELON, WB BUSCHOW, KHJ AF YETHIRAJ, M YELON, WB BUSCHOW, KHJ TI MAGNETIC-STRUCTURE OF RARE-EARTH IRON CARBIDES SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article ID PERMANENT-MAGNETS; FE; ND AB The ternary compounds RE2Fe14B (RE = rare earth) have a tetragonal structure and represent an important advance in permanent magnet technology. In this study, we present reports on similar compounds where the boron atoms are replaced substitutionally by carbon. We have determined the nuclear and magnetic structure of the compounds Lu2Fe14C, Er2Fe14C and Dy2Fe14C. We compare this to the structure of the corresponding borides and find that although the unit cell of the carbides is contracted substantially in the c-axis direction, the arrangement of magnetic moments within this structure is very similar to that in the rare-earth iron borides. C1 UNIV MISSOURI,MISSOURI RES REACTOR,NEUTRON SCATTERING GRP,COLUMBIA,MO 65211. PHILIPS RES LABS,5600 JA EINDHOVEN,NETHERLANDS. RP YETHIRAJ, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,P LANSCE,MS H805,LOS ALAMOS,NM 87545, USA. NR 13 TC 10 Z9 10 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1991 VL 97 IS 1-3 BP 45 EP 52 DI 10.1016/0304-8853(91)90160-C PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA FY520 UT WOS:A1991FY52000008 ER PT J AU AOKI, H CRABTREE, GW JOSS, W HULLIGER, F AF AOKI, H CRABTREE, GW JOSS, W HULLIGER, F TI NEW HIGH-FREQUENCY DHVA BRANCH OF CESB SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article ID FERMI-SURFACE AB A new de Haas-van Alphen high-frequency branch in the ferromagnetic phase of CeSb is reported. The new frequency is discussed in the light of the weak coupling model with localized f orbitals and the p-f mixing model. C1 MAX PLANCK INST SOLID STATE RES,F-38042 GRENOBLE,FRANCE. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. SWISS FED INST TECHNOL,FESTKORPERPHYS LAB,CH-8092 ZURICH,SWITZERLAND. RP AOKI, H (reprint author), NATL RES INST MET,2-3-12 NAKAMEGURO,MEGURO KU,TOKYO 153,JAPAN. NR 11 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1991 VL 97 IS 1-3 BP 169 EP 170 DI 10.1016/0304-8853(91)90176-B PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA FY520 UT WOS:A1991FY52000024 ER PT J AU PHARR, GM OLIVER, WC HARDING, DS AF PHARR, GM OLIVER, WC HARDING, DS TI NEW EVIDENCE FOR A PRESSURE-INDUCED PHASE-TRANSFORMATION DURING THE INDENTATION OF SILICON SO JOURNAL OF MATERIALS RESEARCH LA English DT Note ID BEHAVIOR AB Scanning electron micrographs of indents in (111) silicon reveal that a thin layer of material immediately adjacent to the indenter is plastically extruded. The fact that the material can be deformed in this way indicates that it has metallic-like mechanical properties. This is presented as new evidence that a pressure-induced phase transformation to the metallic state occurs during the indentation of silicon. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP PHARR, GM (reprint author), RICE UNIV,DEPT MAT SCI,POB 1892,HOUSTON,TX 77251, USA. NR 8 TC 179 Z9 182 U1 3 U2 17 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 JUN PY 1991 VL 6 IS 6 BP 1129 EP 1130 DI 10.1557/JMR.1991.1129 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200001 ER PT J AU ROSSI, F NASTASI, M COHEN, M OLSEN, C TESMER, JR EGERT, C AF ROSSI, F NASTASI, M COHEN, M OLSEN, C TESMER, JR EGERT, C TI ION-BEAM MIXING OF U-BASED BILAYERS SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ENERGETIC DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; THERMAL SPIKES; TEMPERATURE; SIMULATION; METALS AB Bilayer samples of U/Al, U/Ti, U/Si, and U/C have been ion beam mixed with 400 keV Ar and U/Al with Xe ions at doses from 2 x 10(15) to 1 x 10(17) ions/cm2. Mixing experiments were performed at various temperatures between 77 and 420 K. The amount of interfacial mixing, 4Dt, follows a linear dose dependence below a critical temperature, depending on the system studied. Below this temperature, the mixing efficiency, defined as partial-(4Dt)/partial-PHI where 4Dt is the mixing and PHI is the dose, is temperature independent. Its value, as well as the value of the transition temperature, agrees well with the thermodynamical model of chemically biased diffusion in a thermal spike for the four systems tested. The transition between the thermal spike regime and the temperature enhanced mixing regime was interpreted on the basis of an intracascade mechanism. The formation of an intermetallic compound in the U/Al system was detected and interpreted on a qualitative basis by crystallographic considerations. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545. MARTIN MARIETTA Y12 PLANT,OAK RIDGE,TN 37831. OI Rossi, Francois/0000-0003-3090-1398 NR 28 TC 17 Z9 17 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1991 VL 6 IS 6 BP 1175 EP 1187 DI 10.1557/JMR.1991.1175 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200009 ER PT J AU XU, JH FREEMAN, AJ AF XU, JH FREEMAN, AJ TI BANDFILLING AND STRUCTURAL STABILITY OF TRIALUMINIDES - YAL3, ZRAL3, AND NBAL3 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID PHASE-STABILITY; ELECTRONIC-STRUCTURE; CRYSTAL-STRUCTURE; ALLOYS; MON; SUPERCONDUCTOR; SYSTEM; POWDER; WC AB The cohesive properties and electronic structures versus the structural stability of transition-metal trialuminides YAl3, ZrAl3, and NbAl3 in their cubin L1(2), tetragonal D0(22), and naturally stable forms (i.e., the D0(19) structure for YAl3 and the D0(23) structure for ZrAl3) have been investigated using a total energy local-density approach. The variation of structural stability with transition-metal constituent can be simply understood in terms of the bandfilling of the bonding states in the rigid band sense, with the valence electrons gradually filling the bonding states on going from YAl3, ZrAl3 to NbAl3. This leads to a phase transition from the cubic L1(2) structure (for YAl3) to the tetragonal D0(22) structure (for NbAl3). It is argued that this criterion may also apply to explain the variation of the structural stability of other transition-metal compounds (such as transition-metal carbides, nitrides, silicides, etc.) that are dominated by covalent interactions between the transition-metal d and the metalloid p states. C1 ACAD SCI CHINA, SHANGHAI INST MET, SHANGHAI 200050, PEOPLES R CHINA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RP NORTHWESTERN UNIV, DEPT PHYS & ASTRON, EVANSTON, IL 60208 USA. NR 57 TC 36 Z9 36 U1 0 U2 7 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1991 VL 6 IS 6 BP 1188 EP 1199 DI 10.1557/JMR.1991.1188 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200010 ER PT J AU WAS, GS MANTL, S AF WAS, GS MANTL, S TI LATTICE LOCATION AND HARDNESS OF TA-IMPLANTED NI3AL SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MECHANICAL-PROPERTIES; TEMPERATURE-DEPENDENCE; ORDERED ALLOYS; NICKEL; SIMULATION; PHASE AB Implantation of Ta into single crystal Ni3Al was conducted to determine the degree of surface hardening in monolithic alloys in relation to its lattice location. Ta was implanted at 400 keV to doses of 0.07, 0.36, and 2.52 x 10(16) cm-2 along the [100] axis of a [100] crystal of Ni3Al at room temperature. Composition versus depth profiles were determined by RBS, and lattice location of Ta was determined by channeling angular yield scans about the [100] axis. The hardness of the surface was measured by ultra-low load indentation. Results show that implantation softens the surface and that the Ta is randomly distributed between Ni and Al sites. Annealing at 1000-degrees-C/1 h significantly reduces the damage and causes preferential occupation of Al sites by Ta, resulting in a slight increase in surface hardness. Further annealing at 1200-degrees-C/0.25 h increases the surface hardness substantially and increases occupation of Al lattice sites to roughly 84%. Results are consistent with a model in which the as-implanted surface is softened by disordering, and subsequent diffusion of Ta to Al sites during thermal treatment causes hardening of the surface. C1 OAK RIDGE NATL LAB, DIV MET & CERAM, OAK RIDGE, TN 37831 USA. UNIV MICHIGAN, DEPT NUCL ENGN, ANN ARBOR, MI 48109 USA. RP WAS, GS (reprint author), FORSCHUNGSZENTRUM JULICH, INST SCHICHTTECH & IONENTECH, W-5170 JULICH 1, GERMANY. RI Mantl, Siegfried/L-1317-2013 OI Mantl, Siegfried/0000-0002-4266-0619 NR 25 TC 3 Z9 3 U1 0 U2 1 PU MATERIALS RESEARCH SOC PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1991 VL 6 IS 6 BP 1200 EP 1206 DI 10.1557/JMR.1991.1200 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200011 ER PT J AU JASZCZAK, JA WOLF, D AF JASZCZAK, JA WOLF, D TI ON THE ELASTIC BEHAVIOR OF COMPOSITION-MODULATED SUPERLATTICES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CALCULATING CRITICAL MISFIT; EXACTLY SOLVABLE MODEL; GRAIN-BOUNDARIES; METALLIC SUPERLATTICES; EPITAXIAL SUPERLATTICES; COMPUTER-SIMULATION; SUPER-LATTICES; THIN-FILMS; FCC METALS; CONSTANTS AB Atomistic computer simulations are used to systematically investigate the role of interfacial disorder on the elastic behavior of composition-modulated superlattices of fcc metals, represented by simple Lennard-Jones potentials. The structures, energies, and average elastic properties of four types of superlattices with various degrees of interfacial disorder are computed as a function of the modulation wavelength along [001]. The four superlattice types studied include perfectly coherent, incoherent, and two types derived from these by introducing relative twists about [001] between alternating layers. A 20% lattice-parameter mismatch between the two modulating materials is assumed. Results are compared with our earlier work on unsupported thin films, grain-boundary superlattices, and incoherent superlattices with a 10% lattice-parameter mismatch. The degree of structural disorder at the interfaces is found to correlate well with the magnitude of the elastic anomalies, which cannot be accounted for by anisotropic lattice-parameter changes alone. The grain-boundary superlattices studied earlier are found to provide a good model limit for the elastic behavior of interfacially disordered dissimilar-material superlattices. RP JASZCZAK, JA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 45 TC 17 Z9 17 U1 0 U2 4 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1991 VL 6 IS 6 BP 1207 EP 1218 DI 10.1557/JMR.1991.1207 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200012 ER PT J AU SRINIVASAN, R DEANGELIS, RJ ICE, G DAVIS, BH AF SRINIVASAN, R DEANGELIS, RJ ICE, G DAVIS, BH TI IDENTIFICATION OF TETRAGONAL AND CUBIC STRUCTURES OF ZIRCONIA USING SYNCHROTRON X-RADIATION SOURCE SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CRYSTAL PHASE; ZRO2; PH AB X-ray diffraction from a synchroton source was employed in an attempt to identify the crystal structures in zirconia ceramics produced by the sol-gel method. The particles of chemically precipitated zirconia, after calcination below 600-degrees-C, are very fine, and have a diffracting particle size in the range of 7-15 nm. As the tetragonal and cubic structures of zirconia have similar lattice parameters, it is difficult to distinguish between the two. The tetragonal structure can be identified only by the characteristic splittings of the Bragg profiles from the "c" index planes. However, these split Bragg peaks from the tetragonal phase in zirconia overlap with one another due to particle size broadening. In order to distinguish between the tetragonal and cubic structures of zirconia, three samples were studied using synchrotron radiation source. The results indicated that a sample containing 13 mol % yttria-stabilized zirconia possessed the cubic structure with a0 = 0.51420 +/- 0.00012 nm. A sample containing 6.5 mol % yttria stabilized zirconia was found to consist of a cubic phase with a0 = 0.51430 +/- 0.00008 nm. Finally, a sample which was precipitated from a pH 13.5 solution was observed to have the tetragonal structure with a0 = 0.51441 +/- 0.00085 nm and c0 = 0.51902 +/- 0.00086. C1 UNIV NEBRASKA,DEPT MECH ENGN,LINCOLN,NE 68688. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP SRINIVASAN, R (reprint author), UNIV KENTUCKY,CTR APPL ENERGY RES,3572 IRON WORKS PIKE,LEXINGTON,KY 40511, USA. NR 26 TC 63 Z9 63 U1 1 U2 17 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 JUN PY 1991 VL 6 IS 6 BP 1287 EP 1292 DI 10.1557/JMR.1991.1287 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200019 ER PT J AU WEBER, WJ EBY, RK EWING, RC AF WEBER, WJ EBY, RK EWING, RC TI ACCUMULATION OF STRUCTURAL DEFECTS IN ION-IRRADIATED CA2ND8(SIO4)6O2 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID X-RAY; LATTICE-DEFECTS; RADIATION; DAMAGE; BOMBARDMENT; UO2; AMORPHIZATION; DIFFRACTION; INGROWTH; MONAZITE AB Ion irradiations of the rare-earth orthosilicate, Ca2Nd8(SiO4)6O2, have been carried out using both alpha particles (emitted from a (PuO2)-Pu-238 source) and 3 MeV argon ions. The unit cell exhibits anisotropic expansion under irradiation, consistent with expectations based on the polyhedral connectivity within the structure. A least-squares analysis of the interatomic distances suggests that the unit-cell expansions are primarily due to changes in oxygen-oxygen distances and cation separations between neighboring polyhedra rather than to bonds within polyhedra. The irradiation-induced change in unit-cell volume is proportional to 1 - exp(-BD), where B is an annealing rate constant and D is the dose, in agreement with a model for the accumulation of isolated point defects in the structure. The volume expansion saturates at 2.56% and 1.40% for the alpha and argon irradiations, respectively. Analysis of the results suggests that a significant fraction of the defects produced in the argon-ion displacement cascades are lost to in-cascade recombination. Differential scanning calorimetry of powder irradiated with 3 MeV argon ions to 20 ions/nm2 reveals an exothermic recovery peak at 350-degrees-C with an activation energy of 1.3 +/- 0.1 eV and average stored energy release of 28.2 J/g. There is no evidence for amorphization of this material under alpha or argon irradiation. C1 UNIV NEW MEXICO, DEPT GEOL, ALBUQUERQUE, NM 87131 USA. RP WEBER, WJ (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 31 TC 16 Z9 16 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 JUN PY 1991 VL 6 IS 6 BP 1334 EP 1345 DI 10.1557/JMR.1991.1334 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200024 ER PT J AU JERVIS, TR HIRVONEN, JP NASTASI, M AF JERVIS, TR HIRVONEN, JP NASTASI, M TI POST DEPOSITION EXCIMER LASER PROCESSING OF MOSX THIN-FILMS SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID MORPHOLOGICAL PROPERTIES; LUBRICATION; PERFORMANCE; COATINGS AB We have examined the effect of excimer laser surface processing and doping with Au on the mechanical, tribological, and bonding properties of MoS(x) thin films. We find that the effects of processing are manifested primarily in the surface of the films, but that there is also some film-substrate interaction during high fluence processing. The changes are sufficient to dramatically alter the wear life of the films. At low loads, laser processing alone reduces the run-in period and increases wear life. At higher loads, processing reduces wear life, although the run-in period is still short. These results are understood in terms of changes in the hardness of the surface of the films. Laser processing renders deposited films insensitive to high humidity storage. After laser processing, Raman spectroscopy shows changes in bonding to that characteristic of single crystal MoS2. Laser doping with Au results in wear life comparable to or greater than that of unprocessed films even at the highest loads used. Thus, laser doped MoS(x) films show lower initial friction, comparable wear life, and may exhibit greater environmental stability than as-deposited films. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP JERVIS, TR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 30 TC 9 Z9 9 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 JUN PY 1991 VL 6 IS 6 BP 1350 EP 1357 DI 10.1557/JMR.1991.1350 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200026 ER PT J AU LANGFORD, SC JENSEN, LC DICKINSON, JT PEDERSON, LR AF LANGFORD, SC JENSEN, LC DICKINSON, JT PEDERSON, LR TI ALKALI EMISSION ACCOMPANYING FRACTURE OF SODIUM-SILICATE GLASSES SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SINGLE-CRYSTAL MGO; FUSED-SILICA; ELECTRON; SURFACES; CRACK; EJECTA; TIP AB Measurements of atomic Na emission accompanying the fracture of sodium trisilicate glass and a soda lime glass in vacuum were made by quadrupole mass spectroscopy and surface ionization techniques. Peak Na-degrees emission intensities occur some 3-6 ms after the fracture event and decay over tens of milliseconds. This behavior is attributed to the diffusion of Na+ ions into a layer of damaged material at the surface where the ions are subsequently neutralized and thermally emitted as Na-degrees. Charge carriers generated during fracture and subsequently trapped at defect sites apparently play important roles in charge compensating Na+ diffusion and in neutralizing Na+. During the first 300 ms following fracture, we also observe intense, short lived (400-mu-s) bursts in Na-degrees emission which may be associated with catastrophic relaxation of residual stresses. The kinetics of Na emission suggest that the relaxation of newly formed glass surfaces involves rather complex surface physical and chemical processes. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP LANGFORD, SC (reprint author), WASHINGTON STATE UNIV, DEPT PHYS, PULLMAN, WA 99164 USA. NR 36 TC 15 Z9 15 U1 2 U2 5 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD JUN PY 1991 VL 6 IS 6 BP 1358 EP 1368 DI 10.1557/JMR.1991.1358 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA FQ052 UT WOS:A1991FQ05200027 ER PT J AU GINOCCHIO, JN AF GINOCCHIO, JN TI A NEW IDENTITY FOR SOME 6-J SYMBOLS SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID DOUBLE CHARGE-EXCHANGE AB A new sum rule is derived for the six-j symbol in which four of the angular momenta are equal. This sum rule differs from other sum rules in that the six-j symbol is not weighted by 2L + 1 where L is the angular momentum being summed over. RP GINOCCHIO, JN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 8 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 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD JUN PY 1991 VL 32 IS 6 BP 1430 EP 1432 DI 10.1063/1.529298 PG 3 WC Physics, Mathematical SC Physics GA FN217 UT WOS:A1991FN21700002 ER PT J AU MARTIN, P BAKER, GA AF MARTIN, P BAKER, GA TI 2-POINT QUASI-FRACTIONAL APPROXIMANT IN PHYSICS - TRUNCATION ERROR SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID FRACTIONAL APPROXIMATIONS; RATIONAL INTERPOLANTS AB The quasifractional approximation method is developed in a systematic manner. This method uses simultaneously the power series, and at a second point, the asymptotic expansion. The usual form of the approximants is two or more rational fractions, in terms of a suitable variable, combined with auxiliary nonfractional functions. Coincidence in the singularities in the region of interest is pursued. Equal denominators in the rational fractions is required so that the solution of only linear algebraic equations is needed to determine the parameters of the approximant. An upper bound is obtained for the truncation error for a certain class of functions, which contains most of the functions for which this method has been applied so far. It is shown that quasifractional approximants can be derived as a mixed German and Latin polynomial problem in the context of Hermite-Pade approximation theory. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP MARTIN, P (reprint author), UNIV SIMON BOLIVAR,DEPT FIS,APARTADO 89000,CARACAS,VENEZUELA. NR 18 TC 33 Z9 35 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 JUN PY 1991 VL 32 IS 6 BP 1470 EP 1477 PG 8 WC Physics, Mathematical SC Physics GA FN217 UT WOS:A1991FN21700010 ER PT J AU POLLACK, SS SPRECHER, RF FROMMELL, EA AF POLLACK, SS SPRECHER, RF FROMMELL, EA TI COLOR FORMATION IN STYRENE ZEOLITE COMPLEXES SO JOURNAL OF MOLECULAR CATALYSIS LA English DT Article AB Styrene adsorbed in the channels of ZSM-5 and other zeolites and then activated by heat or irradiation produces pigmented pink to purple complexes. The complexes were prepared with zeolite containing some aluminum substituting for silicon in the structure, H+ in some of the exchange sites, styrene or various substituted styrenes, and some activating agent. The colors are probably produced by cation radicals formed by the reaction of the H+ of the zeolites and the site of the double bond in the vinyl group. Developing a colorimetric method for measuring the number of acid sites in zeolites may be possible. RP POLLACK, SS (reprint author), PITTSBURGH ENERGY TECHNOL CTR,POB 10940,PITTSBURGH,PA 15236, USA. NR 10 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-5102 J9 J MOL CATAL PD JUN PY 1991 VL 66 IS 2 BP 195 EP 203 DI 10.1016/0304-5102(91)80013-S PG 9 WC Chemistry, Physical SC Chemistry GA FR615 UT WOS:A1991FR61500013 ER PT J AU XENOPOULOS, A NARTEN, AH CHENG, JL WUNDERLICH, B AF XENOPOULOS, A NARTEN, AH CHENG, JL WUNDERLICH, B TI INVESTIGATIONS OF THE TRANSITIONS OF SOME TETRAALKYLAMMONIUM HALIDES BY DSC, NMR, AND X-RAY-DIFFRACTION SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT INTERNATIONAL DISCUSSION MEETING ON RELAXATION IN COMPLEX SYSTEMS CY JUN 18-29, 1990 CL CRETE, GREECE SP USN, OFF NAVAL RES, US DOE, MAX PLANCK INST POLYM RES, ELLENIC POLYM ASSOC, CHALMERS UNIV TECHNOL, EUROPEAN OFF AEROSP RES & DEV, AIR FORCE SCI RES, USA, R&D & STAND GRP, RHEOMETRICS, SUMITOMO PLAST AMER, HOECHST CELENESE RES DIV ID CONDIS CRYSTALS; SMALL MOLECULES AB The transitions of several symmetric tetraalkylammonium halides were studied by differential scanning calorimetry (DSC), solid-state nuclear magnetic resonance (NMR) and X-ray diffraction. The reversibility of the transitions of Bu4NI is investigated by cycling of the samples in the DSC. A plastic-crystalline phase is found and characterized. A glass transition is observed for Bu4NCl at 230 K. Solid-state CP-MAS C-13 NMR is performed on Hex4NI in order to reveal the large-amplitude molecular motion. The DSC transitions are confirmed by changes in the chemical shifts, but additional, more continuous changes are seen. Condis-crystalline phases are probable for the latter two salts. Room-temperature X-ray diffraction on various iodides shows that the appropriate d-spacings increase linearly with size of the alkyl groups. C1 OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP XENOPOULOS, A (reprint author), UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996, USA. NR 24 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 113 EP 119 DI 10.1016/0022-3093(91)90285-E PN 1 PG 7 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV574 UT WOS:A1991FV57400023 ER PT J AU SCHWEIZER, KS AF SCHWEIZER, KS TI MODE MODE-COUPLING THEORY OF THE DYNAMICS OF POLYMERIC LIQUIDS SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT INTERNATIONAL DISCUSSION MEETING ON RELAXATIONS IN COMPLEX SYSTEMS CY JUN 18-29, 1990 CL CRETE, GREECE ID INTEGRAL-EQUATION THEORY; VISCOELASTIC PROPERTIES; PHENOMENOLOGICAL THEORY; MELTS; ENTANGLEMENTS; DIFFUSION; BLENDS; CHAIN AB A first principles, statistical mechanical theory of the dynamics of polymer liquids has been developed using the generalized Langevin equation and molecular-scale mode-mode-coupling methods. The essential physics of chain uncrossability and connectivity is contained in a time-dependent dynamical friction matrix, which quantitatively describes fluctuating force correlations and many-body caging. For very long chain fluids, the predicted molecular weight dependences of the transport coefficients agree qualitatively with the reptation/tube theory. However, a more general physical interpretation appears to exist, and a natural analogy with critical slowing down is suggested. Polymer shape fluctuation effects are also included in a microscopic fashion, and when dominant generate both a stretched exponential terminal relaxation and a 3.55 exponent for the viscosity-chain-length scaling law. Anomalous segmental and center-of-mass diffusion at early times are also studied. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 28 TC 46 Z9 46 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 643 EP 649 DI 10.1016/0022-3093(91)90662-P PN 2 PG 7 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV576 UT WOS:A1991FV57600018 ER PT J AU FELCHER, GP KARIM, A RUSSELL, TP AF FELCHER, GP KARIM, A RUSSELL, TP TI INTERDIFFUSION AT THE INTERFACE OF POLYMERIC BILAYERS - EVIDENCE FOR REPTATION SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT INTERNATIONAL DISCUSSION MEETING ON RELAXATIONS IN COMPLEX SYSTEMS CY JUN 18-29, 1990 CL CRETE, GREECE ID DIFFUSION AB Neutron reflection is used to study the interdiffusion in equal molecular weight polystyrene bilayer melts with a spatial resolution of 10 angstrom. Interfacial widths and concentration profiles at the bilayer interface are obtained for annealing times up to and beyond the reptation time, tau-d. For t < tau-d, the reptation model predicts a mean square displacement of monomers whose time dependence is a power law, the exponent of which changes with time. For the relatively lightweight polymers of M approximately 233 000, the mean square displacements of monomers is in general agreement with predictions; the permanence of a discontinuity at the interface - which also follows from the reptation model - is observed only for molecular weights M approximately 1 000 000. C1 IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. RP FELCHER, GP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 16 TC 16 Z9 16 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 703 EP 708 DI 10.1016/0022-3093(91)90671-R PN 2 PG 6 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV576 UT WOS:A1991FV57600027 ER PT J AU YU, H BINDER, K SCHWEIZER, K MCKENNA, G MUTHUKUMAR, M SILLESCU, H DONTH, EJ STRUIK, L LODGE, TP PHILLIES, G OSAKI, K RICHTER, D BERRY, G ADAM, M FELCHER, G NGAI, K OKONSKI, C HILFER, R GREST, G DYMEK, C WANG, CH AF YU, H BINDER, K SCHWEIZER, K MCKENNA, G MUTHUKUMAR, M SILLESCU, H DONTH, EJ STRUIK, L LODGE, TP PHILLIES, G OSAKI, K RICHTER, D BERRY, G ADAM, M FELCHER, G NGAI, K OKONSKI, C HILFER, R GREST, G DYMEK, C WANG, CH TI POLYMER DIFFUSION, DYNAMICS AND VISCOELASTICITY - DISCUSSION SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Discussion C1 UNIV MAINZ, INST PHYS, STAUDINGER WEG 7, W-6500 MAINZ, GERMANY. UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. USN, RES LAB, WASHINGTON, DC 20375 USA. WORCESTER POLYTECH INST, DEPT PHYS, WORCESTER, MA 01605 USA. SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. UNIV MASSACHUSETTS, DEPT POLYMER SCI & ENGN, AMHERST, MA 01003 USA. FORSCHUNGSZENTRUM JULICH, INST FESTKORPERFORSCH, W-5170 JULICH 1, GERMANY. RI Phillies, George/E-8109-2011; Richter, Dieter/H-3701-2013 OI Richter, Dieter/0000-0003-0719-8470 NR 6 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 EI 1873-4812 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 742 EP 754 PN 2 PG 13 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV576 UT WOS:A1991FV57600033 ER PT J AU MARTIN, SW PATEL, HK BORSA, F TORGESON, D AF MARTIN, SW PATEL, HK BORSA, F TORGESON, D TI MULTIPLE FREQUENCY SPIN-LATTICE RELAXATION-TIME AND IONIC-CONDUCTIVITY MEASUREMENTS OF LI2S+SIS2 GLASSES FROM 1-HZ TO 40-MHZ SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT INTERNATIONAL DISCUSSION MEETING ON RELAXATIONS IN COMPLEX SYSTEMS CY JUN 18-29, 1990 CL CRETE, GREECE ID NUCLEAR MAGNETIC-RESONANCE AB Many measurements have been made of the temperature dependence of the spin-lattice relaxation time T1 for ionically conducting glasses and the ubiquitous observation is that the activation energy for T1 ranges from a factor 2-5 lower than the dc ionic conductivity activation energy for the same glass. This has prompted much deserved discussion and yet a definitive solution to the discrepancy has not been advanced. In this study, wide frequency range measurements of both T1 and sigma-ac have been made on glasses in the highly conducting series Li2S + SiS2 to test the hypothesis that the source of the discrepancy lies not in two fundamentally different phenomena being measured by the two different techniques, but rather in the simpler fact that the timescales that they use to measure the same phenomena are vastly different. In NMR, the frequencies used are always above 1 MHz and always correspond to a frequency-dependent regime of T1, whereas the conductivity is measured as a frequency-independent quantity. These highly conducting glasses provide the rare opportunity to compare activation energies for both NMR and conductivity under conditions of frequency independence and it is found that the two activation energies thus determined agree within experimental error. The source of the discrepancy reported until now is suggested to be due to the fact that the conductivities of glasses have not been high enough to show frequency-independent behavior at the NMR frequencies below T(g). C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES NATL LAB,AMES,IA 50011. RP MARTIN, SW (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011, USA. NR 13 TC 15 Z9 15 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 1041 EP 1045 DI 10.1016/0022-3093(91)90721-H PN 2 PG 5 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV576 UT WOS:A1991FV57600077 ER PT J AU BATES, JB WANG, JC CHU, YT AF BATES, JB WANG, JC CHU, YT TI INTERFACE AND BULK RELAXATION IN SOLID IONIC CONDUCTORS SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT INTERNATIONAL DISCUSSION MEETING ON RELAXATIONS IN COMPLEX SYSTEMS CY JUN 18-29, 1990 CL CRETE, GREECE ID METAL-ELECTROLYTE INTERFACES; SURFACE-TOPOGRAPHY AB The frequency dependent response of solid ionic conductors (solid electrolytes) to a small amplitude ac voltage applied through dc blocking metal contacts is due to polarization from two sources: (i) charge accumulation at the metal-electrolyte interfaces and (ii) displacement of bound charges and defects within the electrolyte. These give rise to a characteristic constant phase angle behavior of the interface impedance and bulk permittivity above the loss peak. The interface impedance is attributed to ion diffusion in screened regions near the electrode surface while the permittivity of the electrolyte is modeled using a temperature dependent distribution of activation energies for ion hopping in double potential wells. RP BATES, JB (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN, USA. NR 18 TC 10 Z9 10 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1991 VL 131 BP 1046 EP 1052 DI 10.1016/0022-3093(91)90722-I PN 2 PG 7 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA FV576 UT WOS:A1991FV57600078 ER EF