FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Wetzel, C Fischer, S Kruger, J Haller, EE Molnar, RJ Moustakas, TD Mokhov, EN Baranov, PG AF Wetzel, C Fischer, S Kruger, J Haller, EE Molnar, RJ Moustakas, TD Mokhov, EN Baranov, PG TI Strongly localized excitons in gallium nitride SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; DOPED GAN; LUMINESCENCE; SILICON; LAYERS; CD AB We report on strong excitonic luminescence in wurtzite GaN at 3.309 and 3.365 eV (T = 6 K). These lines Lie well below the band gap and are found commonly in layers grown by different techniques and on different substrates. From detailed photoluminescence investigations we find small thermal activation energies and a very weak electron-phonon coupling. The photoluminescence behavior under hydrostatic pressure is indicative of strongly localized defects. These findings are similar to observations of excitons localized at extended defects such as dislocations in II-VI compounds. (C) 1995 American Institute of Physics. C1 BOSTON UNIV,DEPT ELECT COMP & SYST ENGN,MOLEC BEAM EPTIAXY LAB,BOSTON,MA 02215. AF IOFFE PHYS TECH INST,ST PETERSBURG 194021,RUSSIA. RP Wetzel, C (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Мохов, Евгений/E-4903-2014; Baranov, Pavel/D-6824-2014; Moustakas, Theodore/D-9249-2016; Wetzel, Christian/O-4017-2014 OI Moustakas, Theodore/0000-0001-8556-884X; Wetzel, Christian/0000-0002-6055-0990 NR 32 TC 68 Z9 71 U1 2 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 29 PY 1996 VL 68 IS 18 BP 2556 EP 2558 DI 10.1063/1.116182 PG 3 WC Physics, Applied SC Physics GA UG866 UT WOS:A1996UG86600032 ER PT J AU Klein, DL McEuen, PL Katari, JEB Roth, R Alivisatos, AP AF Klein, DL McEuen, PL Katari, JEB Roth, R Alivisatos, AP TI An approach to electrical studies of single nanocrystals SO APPLIED PHYSICS LETTERS LA English DT Article ID SPECTROSCOPY; MONOLAYERS; FILMS; GOLD AB We present electrical measurements of single Au and CdSe nanocrystals. The devices are fabricated using a hybrid scheme which combines electron beam lithography and wet chemistry to bind nanocrystals in tunneling contact between two closely spaced metallic leads. The current-voltage characteristics of these devices exhibit a Coulomb staircase with a charging energy of similar to 50 meV. This technique is readily adapted to the study of a host of nanocrystals made by solution chemistry. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,INST MOLEC DESIGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP Klein, DL (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 18 TC 279 Z9 284 U1 4 U2 44 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 29 PY 1996 VL 68 IS 18 BP 2574 EP 2576 DI 10.1063/1.116188 PG 3 WC Physics, Applied SC Physics GA UG866 UT WOS:A1996UG86600038 ER PT J AU Feng, JL Murayama, H Wells, JD AF Feng, JL Murayama, H Wells, JD TI Extracting R(b) and R(c) without flavor tagging SO PHYSICAL REVIEW LETTERS LA English DT Article ID HADRONIC Z(0) DECAYS; RADIATIVE-CORRECTIONS; PHOTON PRODUCTION; STANDARD MODEL; ELECTROWEAK; RESONANCE; COUPLINGS; EMISSION AB We note that a flavor tagging independent measurement of the branching fractions R(b) and R(c) may be obtained from the width of hadronic Z decays with a prompt photon, Gamma(q (q) over bar gamma), and an additional theoretical assumption. We find that the current value of Gamma(q (q) over bar gamma) supports the direct measurements and favors generation-blind corrections to quark widths. An updated measurement of Gamma(q (q) over bar gamma) with the currently available LEP data will provide an even stronger constraint. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP Feng, JL (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Murayama, Hitoshi/A-4286-2011 NR 18 TC 4 Z9 4 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3259 EP 3262 DI 10.1103/PhysRevLett.76.3259 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900004 ER PT J AU Czarnecki, A Krause, B Marciano, WJ AF Czarnecki, A Krause, B Marciano, WJ TI Electroweak corrections to the muon anomalous magnetic moment SO PHYSICAL REVIEW LETTERS LA English DT Article ID BROKEN GAUGE THEORIES; RADIATIVE-CORRECTIONS; RENORMALIZATION AB Bosonic two-loop electroweak radiative corrections to the muon's anomalous magnetic moment, a(mu) = (g(mu) - 2)/2, are presented. We find Delta a(mu)(EW)(2 loop bosonic)/a(mu)(EW) (1 loop) approximate to (alpha/pi) X [-3.6 ln(M(w)(2)/m(mu)(2)) + 0.10] approximate to -0.11 for M(Higgs) approximate to 250 GeV. Combining that result with our previous two-loop fermionic calculation, we obtain an overall 22.6% reduction in a(mu)(EW) from 195 X 10(-11) to 151(4) x 10(-11). Implications for the full standard model prediction and an upcoming high precision measurement of a, are briefly discussed. We also give the two-loop electroweak corrections to the anomalous magnetic moments of electron and tau lepton; they result in a reduction of the one-loop estimates by 35% and 15%, respectively. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Czarnecki, A (reprint author), UNIV KARLSRUHE,INST THEORET TEILCHENPHYS,D-76128 KARLSRUHE,GERMANY. NR 41 TC 241 Z9 241 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3267 EP 3270 DI 10.1103/PhysRevLett.76.3267 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900006 ER PT J AU Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alitti, J Alvarez, G Alves, GA Amidi, E Amos, N Anderson, EW Aronson, SH Astur, R Avery, RE Baden, A Balamurali, V Balderston, J Baldin, B Bantly, J Bartlett, JF Bazizi, K Bendich, J Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Bischoff, A Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Coban, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI De, K Demarteau, M Demina, R Denisenko, K Denisenko, N Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Dixon, R Draper, P Drinkard, J Ducros, Y Dugad, SR DurstonJohnson, S Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahey, S Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Franzini, P Fuess, S Gallas, E Galyaev, AN Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glebov, V Glenn, S Glicenstein, JF Gobbi, B Goforth, M Goldschmidt, A Gomez, B Goncharov, PI Solis, JLG Gordon, H Goss, LT Graf, N Grannis, PD Green, DR Green, J Greenlee, H Griffin, G Grossman, N Grudberg, P Grunendahl, S Gu, WX Guglielmo, G Guida, JA Guida, JM Guryn, W Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hatcher, R Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Hu, T Huehn, T Igarashi, S Ito, AS James, E Jaques, J Jerger, SA Jiang, JZY JoffeMinor, T Johari, H Johns, K Johnson, M Johnstad, H Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kerth, L Kim, CL Kim, SK Klatchko, A Klima, B Klochkov, BI Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kourlas, J Kozelov, AV Kozlovski, EA Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Landsberg, G Lebrat, JF Leflat, A Li, H Li, J Li, YK LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Mani, S Mao, HS Margulies, S Markeloff, R Markosky, L Marshall, T Martin, MI Marx, M May, B Mayorov, AA McCarthy, R McKibben, T McKinley, J McMahon, T Melanson, HL Neto, JRTD Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS MohammadiBaarmand, M Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Mudan, M Murphy, C Murphy, CT Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Neis, E Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, CH Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peryshkin, A Peters, M Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rao, MVS Rapidis, PA Rasmussen, L Read, AL Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shao, YY Shivpuri, RK Shupe, M Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snyder, S Solomon, J Sood, PM Sosebee, M Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Streets, K Strovink, M Sznajder, A Taketani, A Tamburello, P Tarazi, J Tartaglia, M Taylor, TL Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Virador, PRG Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H Wen, F White, A White, JT Wightman, JA Wilcox, J Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, DH Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A AF Abachi, S Abbott, B Abolins, M Acharya, BS Adam, I Adams, DL Adams, M Ahn, S Aihara, H Alitti, J Alvarez, G Alves, GA Amidi, E Amos, N Anderson, EW Aronson, SH Astur, R Avery, RE Baden, A Balamurali, V Balderston, J Baldin, B Bantly, J Bartlett, JF Bazizi, K Bendich, J Beri, SB Bertram, I Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Bischoff, A Biswas, N Blazey, G Blessing, S Bloom, P Boehnlein, A Bojko, NI Borcherding, F Borders, J Boswell, C Brandt, A Brock, R Bross, A Buchholz, D Burtovoi, VS Butler, JM Carvalho, W Casey, D CastillaValdez, H Chakraborty, D Chang, SM Chekulaev, SV Chen, LP Chen, W Chopra, S Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Coban, WG Cochran, J Cooper, WE Cretsinger, C CullenVidal, D Cummings, MAC Cutts, D Dahl, OI De, K Demarteau, M Demina, R Denisenko, K Denisenko, N Denisov, D Denisov, SP Diehl, HT Diesburg, M DiLoreto, G Dixon, R Draper, P Drinkard, J Ducros, Y Dugad, SR DurstonJohnson, S Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Evdokimov, VN Fahey, S Fahland, T Fatyga, M Fatyga, MK Featherly, J Feher, S Fein, D Ferbel, T Finocchiaro, G Fisk, HE Fisyak, Y Flattum, E Forden, GE Fortner, M Frame, KC Franzini, P Fuess, S Gallas, E Galyaev, AN Geld, TL Genik, RJ Genser, K Gerber, CE Gibbard, B Glebov, V Glenn, S Glicenstein, JF Gobbi, B Goforth, M Goldschmidt, A Gomez, B Goncharov, PI Solis, JLG Gordon, H Goss, LT Graf, N Grannis, PD Green, DR Green, J Greenlee, H Griffin, G Grossman, N Grudberg, P Grunendahl, S Gu, WX Guglielmo, G Guida, JA Guida, JM Guryn, W Gurzhiev, SN Gutierrez, P Gutnikov, YE Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hansen, S Hatcher, R Hauptman, JM Hedin, D Heinson, AP Heintz, U HernandezMontoya, R Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hsieh, F Hu, T Hu, T Hu, T Huehn, T Igarashi, S Ito, AS James, E Jaques, J Jerger, SA Jiang, JZY JoffeMinor, T Johari, H Johns, K Johnson, M Johnstad, H Jonckheere, A Jones, M Jostlein, H Jun, SY Jung, CK Kahn, S Kalbfleisch, G Kang, JS Kehoe, R Kelly, ML Kerth, L Kim, CL Kim, SK Klatchko, A Klima, B Klochkov, BI Klopfenstein, C Klyukhin, VI Kochetkov, VI Kohli, JM Koltick, D Kostritskiy, AV Kotcher, J Kourlas, J Kozelov, AV Kozlovski, EA Krishnaswamy, MR Krzywdzinski, S Kunori, S Lami, S Landsberg, G Lebrat, JF Leflat, A Li, H Li, J Li, YK LiDemarteau, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Liu, YC Lobkowicz, F Loken, SC Lokos, S Lueking, L Lyon, AL Maciel, AKA Madaras, RJ Madden, R Mani, S Mao, HS Margulies, S Markeloff, R Markosky, L Marshall, T Martin, MI Marx, M May, B Mayorov, AA McCarthy, R McKibben, T McKinley, J McMahon, T Melanson, HL Neto, JRTD Merritt, KW Miettinen, H Mincer, A deMiranda, JM Mishra, CS MohammadiBaarmand, M Mokhov, N Mondal, NK Montgomery, HE Mooney, P daMotta, H Mudan, M Murphy, C Murphy, CT Nang, F Narain, M Narasimham, VS Narayanan, A Neal, HA Negret, JP Neis, E Nemethy, P Nesic, D Nicola, M Norman, D Oesch, L Oguri, V Oltman, E Oshima, N Owen, D Padley, P Pang, M Para, A Park, CH Park, YM Partridge, R Parua, N Paterno, M Perkins, J Peryshkin, A Peters, M Piekarz, H Pischalnikov, Y Podstavkov, VM Pope, BG Prosper, HB Protopopescu, S Puseljic, D Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramirez, O Rao, MVS Rapidis, PA Rasmussen, L Read, AL Reucroft, S Rijssenbeek, M Rockwell, T Roe, NA Rubinov, P Ruchti, R Rutherfoord, J Santoro, A Sawyer, L Schamberger, RD Schellman, H Sculli, J Shabalina, E Shaffer, C Shankar, HC Shao, YY Shivpuri, RK Shupe, M Singh, JB Sirotenko, V Smart, W Smith, A Smith, RP Snihur, R Snow, GR Snyder, S Solomon, J Sood, PM Sosebee, M Souza, M Spadafora, AL Stephens, RW Stevenson, ML Stewart, D Stoianova, DA Stoker, D Streets, K Strovink, M Sznajder, A Taketani, A Tamburello, P Tarazi, J Tartaglia, M Taylor, TL Thompson, J Trippe, TG Tuts, PM Varelas, N Varnes, EW Virador, PRG Vititoe, D Volkov, AA Vorobiev, AP Wahl, HD Wang, G Warchol, J Watts, G Wayne, M Weerts, H Wen, F White, A White, JT Wightman, JA Wilcox, J Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Won, E Wood, DR Xu, H Yamada, R Yamin, P Yanagisawa, C Yang, J Yasuda, T Yoshikawa, C Youssef, S Yu, J Yu, Y Zhang, DH Zhu, Q Zhu, ZH Zieminska, D Zieminski, A Zverev, EG Zylberstejn, A TI Search for right-handed W bosons and heavy W' in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID HADRON COLLIDERS; MODELS AB We report on a search for right-handed W bosons (W-R) with mass greater than 200 GeV/c(2). We used data collected with the DO detector at the Fermilab Tevatron p (p) over bar collider at root s = 1.8 TeV to search for W-R decays into an electron and a massive right-handed neutrino W-R(+/-) --> e(+/-)N(R). Using the inclusive electron data, we set mass limits independent of the N-R decay: m(WR) > 650 GeV/c(2) and m(WR) > 720 GeV/c(2) at the 95% confidence level, valid for m(NR) < 1/2-m(WR) << m(WR), respectively. The latter also represents a new lower limit on the mass of a heavy left-handed W boson (W-') decaying into e nu. In addition, limits on m(WR) valid for larger values of the N-R mass are obtained assuming that NR decays to an electron and two jets. C1 UNIV LOS ANDES,BOGOTA,COLOMBIA. UNIV ARIZONA,TUCSON,AZ 85721. BOSTON UNIV,BOSTON,MA 02215. BROOKHAVEN NATL LAB,UPTON,NY 11973. BROWN UNIV,PROVIDENCE,RI 02912. UNIV BUENOS AIRES,BUENOS AIRES,DF,ARGENTINA. UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF IRVINE,IRVINE,CA 92717. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. CTR BRASILEIRO PESQUISAS FIS,LAFEX,RIO JANEIRO,BRAZIL. CINVESTAV IPN,MEXICO CITY,DF,MEXICO. COLUMBIA UNIV,NEW YORK,NY 10027. UNIV DELHI,DELHI 110007,INDIA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV HAWAII,HONOLULU,HI 96822. UNIV ILLINOIS,CHICAGO,IL 60607. INDIANA UNIV,BLOOMINGTON,IN 47405. IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. KOREA UNIV,SEOUL 136701,SOUTH KOREA. KYUNGSUNG UNIV,PUSAN,SOUTH KOREA. LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. MOSCOW MV LOMONOSOV STATE UNIV,MOSCOW 119899,RUSSIA. UNIV NEBRASKA,LINCOLN,NE 68588. NYU,NEW YORK,NY 10003. NORTHEASTERN UNIV,BOSTON,MA 02115. NO ILLINOIS UNIV,DE KALB,IL 60115. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV NOTRE DAME,NOTRE DAME,IN 46556. UNIV OKLAHOMA,NORMAN,OK 73019. PUNJABI UNIV,CHANDIGARH 160014,INDIA. INST HIGH ENERGY PHYS,PROTVINO 142284,RUSSIA. PURDUE UNIV,W LAFAYETTE,IN 47907. RICE UNIV,HOUSTON,TX 77251. UNIV ESTADUAL RIO DE JANEIRO,RIO JANEIRO,BRAZIL. UNIV ROCHESTER,ROCHESTER,NY 14627. CTR ETUD SACLAY,SERV PHYS PARTICULES,DAPNIA,CEA,GIF SUR YVETTE,FRANCE. SEOUL NATL UNIV,SEOUL,SOUTH KOREA. SUNY STONY BROOK,STONY BROOK,NY 11794. SSC LAB,DALLAS,TX 75237. TATA INST FUNDAMENTAL RES,BOMBAY 400005,MAHARASHTRA,INDIA. UNIV TEXAS,ARLINGTON,TX 76019. TEXAS A&M UNIV,COLLEGE STN,TX 77843. RI Taketani, Atsushi/E-1803-2017; Chekulaev, Sergey/O-1145-2015; de Mello Neto, Joao/C-5822-2013; Sznajder, Andre/L-1621-2016; Aihara, Hiroaki/F-3854-2010; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Leflat, Alexander/D-7284-2012; Klyukhin, Vyacheslav/D-6850-2012; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Kim, Sun Kee/G-2042-2015 OI Taketani, Atsushi/0000-0002-4776-2315; de Mello Neto, Joao/0000-0002-3234-6634; Sznajder, Andre/0000-0001-6998-1108; Aihara, Hiroaki/0000-0002-1907-5964; Klyukhin, Vyacheslav/0000-0002-8577-6531; De, Kaushik/0000-0002-5647-4489; Kim, Sun Kee/0000-0002-0013-0775 NR 24 TC 73 Z9 74 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3271 EP 3276 DI 10.1103/PhysRevLett.76.3271 PG 6 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900007 ER PT J AU Belz, J Cousins, RD Diwan, MV Eckhause, M Ecklund, KM Hancock, AD Highland, VL Hoff, C Hoffmann, GW Irwin, GM Kane, JR Kettell, SH Klein, JR Kuang, Y Lang, K Martin, R May, M McDonough, J Molzon, WR Riley, PJ Ritchie, JL Schwartz, AJ Trandafir, A Ware, B Welsh, RE White, SN Witkowski, MT Wojcicki, SG Worm, S AF Belz, J Cousins, RD Diwan, MV Eckhause, M Ecklund, KM Hancock, AD Highland, VL Hoff, C Hoffmann, GW Irwin, GM Kane, JR Kettell, SH Klein, JR Kuang, Y Lang, K Martin, R May, M McDonough, J Molzon, WR Riley, PJ Ritchie, JL Schwartz, AJ Trandafir, A Ware, B Welsh, RE White, SN Witkowski, MT Wojcicki, SG Worm, S TI Search for the weak decay of an H dibaryon SO PHYSICAL REVIEW LETTERS LA English DT Article ID STABLE DIBARYON; NUCLEAR TARGETS; 12-GEV PROTONS; DIHYPERON; MODEL AB We have searched for a neutral H dibaryon decaying via H --> Lambda n and H --> Sigma(0)n. Our search has yielded two candidate events from which we set an upper limit on the H production cross section. Normalizing to the inclusive Lambda production cross section, we find (d sigma(H)/d Omega)/(d sigma(Lambda)/d Omega) < 6.3 X 10(-6) at 90% C.L., for an H of mass approximate to 2.15 GeV/c(2). C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV CALIF IRVINE,IRVINE,CA 92717. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. PRINCETON UNIV,PRINCETON,NJ 08544. STANFORD UNIV,STANFORD,CA 94309. TEMPLE UNIV,PHILADELPHIA,PA 19122. UNIV TEXAS,AUSTIN,TX 78712. COLL WILLIAM & MARY,WILLIAMSBURG,VA 23187. NR 19 TC 40 Z9 40 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3277 EP 3280 DI 10.1103/PhysRevLett.76.3277 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900008 ER PT J AU Tzeng, KC Mori, WB Decker, CD AF Tzeng, KC Mori, WB Decker, CD TI Anomalous absorption and scattering of short-pulse high-intensity lasers in underdense plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAMAN; WAVES AB The propagation of short-pulse lasers through several Rayleigh lengths of underdense plasma [(1-4)% n(cr)] is studied using multidimensional fully explicit particle-in-cell simulations. The simulations model 80 to 600 fs, 1 mu m wavelength pulses in the intensity range of 1.5 x 10(17) to 3.5 X 10(19) W/cm2. A detailed account is given for the energy lost out of the focal cone due to a combination of collective absorption and scattering losses. The figure of merit for the nonlinear transmission losses of a given pulse length is the amount of Raman forward scattering exponentiation within a Rayleigh length. C1 UNIV CALIF LOS ANGELES,DEPT ELECT ENGN,LOS ANGELES,CA 90095. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Tzeng, KC (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,405 HILGARD AVE,LOS ANGELES,CA 90095, USA. NR 25 TC 71 Z9 71 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3332 EP 3335 DI 10.1103/PhysRevLett.76.3332 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900022 ER PT J AU Sitko, P Yi, SN Yi, KS Quinn, JJ AF Sitko, P Yi, SN Yi, KS Quinn, JJ TI ''Fermi liquid'' shell model approach to composite fermion excitation spectra in fractional quantum Hall states SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIERARCHY AB Numerical results for the energy spectra of N electrons on a spherical surface are used as input data to determine the quasiparticle energies and the pairwise ''Fermi liquid'' interactions of composite fermion (CF) excitations in fractional quantum Hall systems. The quasiparticle energies and their interactions are then used to determine the energy spectra, E vs total angular momentum L, of states containing more than two quasiparticles. The qualitative agreement with the numerical results gives a remarkable new confirmation of the CF picture. C1 WROCLAW TECH UNIV,INST PHYS,PL-50370 WROCLAW,POLAND. KOREA MARITIME UNIV,PUSAN 606791,SOUTH KOREA. PUSAN NATL UNIV,PUSAN 609735,SOUTH KOREA. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Sitko, P (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37969, USA. NR 15 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3396 EP 3399 DI 10.1103/PhysRevLett.76.3396 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900038 ER PT J AU Schumacher, B Westmoreland, M Wootters, WK AF Schumacher, B Westmoreland, M Wootters, WK TI Limitation on the amount of accessible information in a quantum channel SO PHYSICAL REVIEW LETTERS LA English DT Article AB We prove a new result limiting the amount of accessible information in a quantum channel. This generalizes Kholevo's theorem and implies it as a simple corollary. Our proof uses the strong subadditivity of the von Neumann entropy functional S(rho) and a specific physical analysis of the measurement process. The result presented here has application in information obtained from ''weak'' measurements, such as those sometimes considered in quantum cryptography. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. DENISON UNIV,DEPT MATH,GRANVILLE,OH 43023. WILLIAMS COLL,DEPT PHYS,WILLIAMSTOWN,MA 01267. RP Schumacher, B (reprint author), KENYON COLL,DEPT PHYS,GAMBIER,OH 43022, USA. NR 10 TC 55 Z9 56 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 29 PY 1996 VL 76 IS 18 BP 3452 EP 3455 DI 10.1103/PhysRevLett.76.3452 PG 4 WC Physics, Multidisciplinary SC Physics GA UG829 UT WOS:A1996UG82900052 ER PT J AU Iglesias, CA AF Iglesias, CA TI Relativistic corrections to inverse bremsstrahlung in the solar interior - Comment SO PHYSICS LETTERS A LA English DT Article DE opacity; solar interior ID TEMPERATURE STELLAR PLASMA AB A recent examination of inverse bremsstrahlung in the solar interior by Tsytovich et al. [Phys. Lett. A 205 (1995) 199] is shown to predict incorrectly both the sign and size of the relativistic corrections. RP Iglesias, CA (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 11 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD APR 29 PY 1996 VL 213 IS 5-6 BP 313 EP 315 DI 10.1016/0375-9601(96)00132-6 PG 3 WC Physics, Multidisciplinary SC Physics GA UJ275 UT WOS:A1996UJ27500019 ER PT J AU Cartwright, DC Trajmar, S AF Cartwright, DC Trajmar, S TI Resonant electron-impact excitation of vibrational modes in polyatomic molecules SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID CROSS-SECTIONS; TRIATOMIC-MOLECULES; BOOMERANG MODEL; STATES; CO2; SPECTROSCOPY; SCATTERING; SPECTRA AB Measured differential cross sections (DCSs) for electron-impact excitation of bending vibrational modes involving an odd number of vibrational quanta in CO2 by 4 eV incident energy electrons display a strong trend to zero for forward and backward scattering which is characteristic of 'symmetry-forbidden' transitions. This DCS behaviour is postulated here to be produced by a Feshbach resonant mechanism involving a low-lying bent excited state of CO2. The model described here identifies three additional low-lying bent excited states of CO2 which could also be parent states for core-excited Feshbach resonances, one of which may play a role in dissociative attachment in this 3.5-5.0 eV energy region. The resonant vibrational excitation mechanism proposed here is also believed to be operative in other polyatomic molecules and could be investigated by performing selected electron energy-loss measurements within the lowest energy resonance regions of the molecules CO2, N2O, OCS, CS2 and SO2. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Cartwright, DC (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 46 TC 10 Z9 10 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD APR 28 PY 1996 VL 29 IS 8 BP 1549 EP 1562 DI 10.1088/0953-4075/29/8/018 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA UJ320 UT WOS:A1996UJ32000018 ER PT J AU Compton, RN Dunning, FB Nordlander, P AF Compton, RN Dunning, FB Nordlander, P TI On the binding of electrons to CS2: Possible role of quadrupole-bound states SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NEGATIVE-IONS; ATOMS; COLLISIONS; MOLECULES AB Rydberg atoms are known to charge exchange with CS2 resulting in formation of CS2- ions that undergo rapid electric-field-induced detachment in applied fields greater than or similar to 1 kV cm(-1). Here we examine a possible explanation for these observations based on the formation of ions in which the electron is weakly bound by the quadrupole moment (Q(20)=+3.3 au) of the neutral molecule. Theoretical calculations and further analysis of available experimental data suggest that such a mechanism might indeed account for the earlier observations. This is further supported to the observation that charge exchange does not occur in Rydberg atom collisions with COS (Q(20)=-0.2 au). C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. RICE UNIV,DEPT PHYS,HOUSTON,TX 77005. RICE UNIV,RICE QUANTUM INST,HOUSTON,TX 77005. RP Compton, RN (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. RI Nordlander, Peter/A-2560-2008 OI Nordlander, Peter/0000-0002-1633-2937 NR 28 TC 23 Z9 23 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 26 PY 1996 VL 253 IS 1-2 BP 8 EP 12 DI 10.1016/0009-2614(96)00243-6 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UK635 UT WOS:A1996UK63500002 ER PT J AU Mauthe, RJ Marsch, GA Turteltaub, KW AF Mauthe, RJ Marsch, GA Turteltaub, KW TI Improved high-performance liquid chromatography analysis of P-32-postlabeled 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine adducts using in-line precolumn purification SO JOURNAL OF CHROMATOGRAPHY B-BIOMEDICAL APPLICATIONS LA English DT Article DE P-31-postlabelling; DNA adducts; 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-DNA adducts ID DNA ADDUCTS; HETEROCYCLIC AMINES; CARCINOGEN ADDUCTS; COOKED FOOD; IDENTIFICATION; PHIP; HPLC; LIVER; ASSAY AB An improved HPLC-based P-32-postlabeling assay has been developed for the analysis of DNA modified with the food carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Postlabeled samples are loaded onto a C-18 precolumn and adducted bases are retained while excess radioactivity and unmodified DNA bases are eluted directly to waste through a switching valve. The use of this HPLC in-line precolumn purification (HIPP) technique allows entire postlabeled samples to be analyzed without prior removal of inorganic phosphate and unmodified DNA bases. The method has a sample to sample precision of 15% and accuracy of 20%, at adduct levels of 2 adducts/10(7) bases and shows a linear relationship between signal and adduction levels from 1 adduct per 10(4) to approximate to 2 +/- 1 adducts per 10(9) bases. Individual postlabeled DNA samples can be analyzed by HPLC in less than 1 h, allowing high throughput. The use of calf-thymus DNA (CT-DNA), highly modified with PhIP, or DNA isolated from mice chronically fed a PhIP-modified diet shows two major PhIP-DNA adduct peaks and three additional minor adduct peaks when labeled under ATP-limiting conditions. Isolation of the HPLC purified peaks and analysis by thin layer chromatography (TLC) matches the five HPLC peaks to the spots typically seen by TLC, including N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (dG-C8-PhIP). Variations in digestion techniques indicate a potential resistance of the PhIP-DNA adducts to the standard enzymatic digestion methods. Attempts at adduct intensification by solid phase extraction, nuclease P1 enrichment or 1-butanol extraction decreased PhIP-DNA adduct peaks and introduced a large early eluting peak. Removal of the 3'-phosphate with nuclease P1 following the kinase labeling reaction simplifies the HPLC profile to one major peak (dG-C8-PhIP monophosphate) with several minor peaks. In addition to the high resolution provided by HPLC separation of the PhIP-DNA adducts, this method can be adjusted for analysis of other DNA adducts and is readily automated for high throughput. C1 LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL PROGRAM,LIVERMORE,CA 94550. FU NCI NIH HHS [NCI CA55861] NR 20 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B-Biomed. Appl. PD APR 26 PY 1996 VL 679 IS 1-2 BP 91 EP 101 DI 10.1016/0378-4347(96)00010-2 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UM591 UT WOS:A1996UM59100012 PM 8998575 ER PT J AU Minarik, WG Ryerson, FJ Watson, EB AF Minarik, WG Ryerson, FJ Watson, EB TI Textural entrapment of core-forming melts SO SCIENCE LA English DT Article ID SIDEROPHILE ELEMENTS; MANTLE; EARTH; ACCRETION; CONSTRAINTS; SYSTEMS AB Small volume fractions of metal-rich, iron-nickel-sulfur-oxygen melt do not form an interconnected network in polycrystalline olivine at pressures up to 11 gigapascals. These results suggest that iron-rich melts could not have migrated downward along olivine grain edges to form Earth's core. Core separation at pressures below 11 gigapascals within planetary bodies must have been facilitated by large degrees of partial melting, resulting in either separation of immiscible silicate and metal-sulfide melts or extraction of the silicate melt to concentrate the metallic remainder. C1 RENSSELAER POLYTECH INST,DEPT EARTH & ENVIRONM SCI,TROY,NY 12180. RP Minarik, WG (reprint author), LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,L-202,POB 808,LIVERMORE,CA 94551, USA. RI Minarik, William/F-5590-2013 OI Minarik, William/0000-0001-5509-5543 NR 33 TC 76 Z9 78 U1 1 U2 12 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 26 PY 1996 VL 272 IS 5261 BP 530 EP 533 DI 10.1126/science.272.5261.530 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UG826 UT WOS:A1996UG82600038 ER PT J AU Wolinsky, SM Korber, BTM Neumann, AU Daniels, M Kunstman, KJ Whetsell, AJ Furtado, MR Cao, YZ Ho, DD Safrit, JT Koup, RA AF Wolinsky, SM Korber, BTM Neumann, AU Daniels, M Kunstman, KJ Whetsell, AJ Furtado, MR Cao, YZ Ho, DD Safrit, JT Koup, RA TI Adaptive evolution of human immunodeficiency virus-type 1 during the natural course of infection SO SCIENCE LA English DT Article ID VESICULAR STOMATITIS-VIRUS; PRIMARY HIV-1 INFECTION; BIOLOGICAL PHENOTYPE; SYNDROME AIDS; CLONAL POOLS; POPULATIONS; TRANSMISSION; PROGRESSION; SEQUENCES; DIVERSITY AB The rate of progression to disease varies considerably among individuals infected with human immunodeficiency virus-type 1 (HIV-1). Analyses of semiannual blood samples obtained from six infected men showed that a rapid rate of CD4 T cell loss was associated with relative evolutionary stasis of the HIV-1 quasispecies virus population. More moderate rates of CD4 T cell loss correlated with genetic evolution within three of four subjects. Consistent with selection by the immune constraints of these subjects, amino acid changes were apparent within the appropriate epitopes of human leukocyte antigen class I-restricted cytotoxic T lymphocytes. Thus, the evolutionary dynamics exhibited by the HIV-1 quasispecies virus populations under natural selection are compatible with adaptive evolution. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. AARON DIAMOND AIDS RES CTR, NEW YORK, NY 10016 USA. ROCKEFELLER UNIV, NEW YORK, NY 10016 USA. RP NORTHWESTERN UNIV, SCH MED, DEPT MED, 303 E CHICAGO AVE, CHICAGO, IL 60611 USA. RI Wolinsky, Steven/B-2893-2012; OI Wolinsky, Steven/0000-0002-9625-6697; Korber, Bette/0000-0002-2026-5757 FU NIAID NIH HHS [AI32535, AI35522, AI45218] NR 94 TC 474 Z9 483 U1 2 U2 22 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD APR 26 PY 1996 VL 272 IS 5261 BP 537 EP 542 DI 10.1126/science.272.5261.537 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UG826 UT WOS:A1996UG82600041 PM 8614801 ER PT J AU Choi, W Camassa, R AF Choi, W Camassa, R TI Weakly nonlinear internal waves in a two-fluid system SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SURFACE GRAVITY-WAVES; FINITE DEPTH; STRATIFIED FLUIDS; SOLITARY WAVES; UNEVEN BOTTOM; PROPAGATION; EVOLUTION; EQUATION AB We derive general evolution equations for two-dimensional weakly nonlinear waves at the free surface in a system of two fluids of different densities. The thickness of the upper fluid layer is assumed to be small compared with the characteristic wavelength, but no restrictions are imposed on the thickness of the lower layer. We consider the case of a free upper boundary for its relevance in applications to ocean dynamics problems and the case of a non-uniform rigid upper boundary for applications to atmospheric problems. For the special case of shallow water, the new set of equations reduces to the Boussinesq equations for two-dimensional internal waves, whilst, for great and infinite lower-layer depth, we can recover the well-known Intermediate Long Wave and Benjamin-One models, respectively, for one-dimensional uni-directional wave propagation. Some numerical solutions of the model for one-dimensional waves in deep water are presented and compared with the known solutions of the uni-directional model. Finally, the effects of finite-amplitude slowly varying bottom topography are included in a model appropriate to the situation when the dependence on one of the horizontal coordinates is weak. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Choi, W (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 26 TC 64 Z9 72 U1 3 U2 11 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 APR 25 PY 1996 VL 313 BP 83 EP 103 DI 10.1017/S0022112096002133 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA UK192 UT WOS:A1996UK19200004 ER PT J AU Shkrob, IA Sauer, MC Yan, J Trifunac, AD AF Shkrob, IA Sauer, MC Yan, J Trifunac, AD TI Transient absorption spectroscopy of high-mobility ions in decalin SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Letter ID IRRADIATED CYCLOHEXANE; PULSE-RADIOLYSIS; RADICAL-CATION; POSITIVE-ION; CIS-DECALIN; HYDROCARBONS; TIME AB Transient absorption spectroscopy is used to demonstrate that pulse radiolysis of a decalin mixture (63% cis-decalin + 37% trans-decalin) with 15 MeV electrons results in formation of high-mobility solvent holes. These radical cations react with perylene with a rate constant of 8.5 x 10(10) mol(-1) dm(3) s(-1). This scavenging is faster by an order of magnitude than ion-molecule reactions of normally diffusing ions (similar to(5-7.5) x 10(9) mol(-1) dm(3) s(-1)). Under conditions of the experiment, the lifetime of the rapidly migrating solvent holes is similar to 150 ns, which identifies them as the high-mobility cations observed by dc and microwave conductivity. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 31 TC 13 Z9 13 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 25 PY 1996 VL 100 IS 17 BP 6876 EP 6878 DI 10.1021/jp960387l PG 3 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300003 ER PT J AU Zhang, XJ Jonah, CD AF Zhang, XJ Jonah, CD TI Effect of temperature on the dynamics of benzophenone anion solvation in alcohol SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PULSE-RADIOLYSIS; POLAR LIQUIDS; ELECTRONS; TIME; SCAVENGERS; METHANOL AB The solvation of the benzophenone anion in 1-propanol, 2-propanol, and 1-butanol has been measured over the temperature range -10 to -50 degrees C. The initial spectra of the benzophenone anion were very similar in all three alcohols. The final spectrum of the benzophenone anion in 2-propanol is less blue-shifted (17 nm) than the spectrum of the anion in 1-propanol and 1-butanol. The activation energies for solvation are 22 kJ/mol for 1 propanol and 1-butanol and 16 kJ/mol for 2-propanol, which are similar to the energy for hydrogen bond breakage in the pure solvents. This suggests that the solvent H-bond breakage plays an important role in anion solvation. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 40 TC 5 Z9 5 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 APR 25 PY 1996 VL 100 IS 17 BP 7042 EP 7049 PG 8 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300025 ER PT J AU Maginn, EJ Bell, AT Theodorou, DN AF Maginn, EJ Bell, AT Theodorou, DN TI Dynamics of long n-alkanes in silicalite: A hierarchical simulation approach SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELASTIC NEUTRON-SCATTERING; MOLECULAR-DYNAMICS; BROWNIAN-MOTION; ZEOLITE ZSM-5; DIFFUSION; METHANE; PROPANE; CHROMATOGRAPHY; ETHANE; XENON AB A hierarchical approach for simulating the diffusion of long n-alkanes in the zeolite silicalite is described. The simulation strategy utilizes concepts from Brownian motion theory and transition state theory and can be used to determine diffusivities for chains at least as long as C-20 using modest computational resources. The results indicate that self-diffusivities decline steadily with increasing chain length up until about n-C-8, after which the self-diffusivities plateau and become nearly constant as a function of chain length. Activation energies for diffusion are constant and equal to 5 kJ/mol for short chains but increase to roughly 12 kJ/mol for chains longer than C-8. A microscopic explanation for these trends is proposed. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV PATRAS,DEPT CHEM ENGN,GR-26500 PATRAI,GREECE. DEMOCRITOS NATL RES CTR PHYS SCI,MOL MODELING MAT GRP,GR-15310 ATHENS,GREECE. OI Theodorou, Doros/0000-0002-4763-9739; Bell, Alexis/0000-0002-5738-4645 NR 43 TC 108 Z9 108 U1 2 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 25 PY 1996 VL 100 IS 17 BP 7155 EP 7173 DI 10.1021/jp953200j PG 19 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300041 ER PT J AU Piocos, EA Han, P Werst, DW AF Piocos, EA Han, P Werst, DW TI Catalytic transformations of olefins on HZSM5 observed by radiolysis EPR SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON-SPIN-RESONANCE; RADICAL CATIONS; H-MORDENITE; MAGNETIC-RESONANCE; ZEOLITE H-ZSM-5; TEMPERATURE; ADSORPTION; OLIGOMERIZATION; CYCLOPENTENE; ALKENES AB A new method for elucidating elementary reaction steps in zeolite catalysis was demonstrated for reactions of isobutene and other monoolefins on HZSM5. Radiolysis was used to ''spin label'' reaction products, and EPR was used for product analysis. The evolution of products was revealed by quenching the reactions cryogenically in a series of equilibration experiments. Isobutene dimerization and isomerization occur on HZSM5 even at 77 K, and cracking occurs below room temperature. The radiolysis/EPR results allow a consistent interpretation of the literature on EPR signals that arise spontaneously upon interaction of acyclic olefins with air-activated H-Mordenite and HZSM5. C1 ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. NR 59 TC 14 Z9 15 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 25 PY 1996 VL 100 IS 17 BP 7191 EP 7199 DI 10.1021/jp953553i PG 9 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300045 ER PT J AU Guzelian, AA Katari, JEB Kadavanich, AV Banin, U Hamad, K Juban, E Alivisatos, AP Wolters, RH Arnold, CC Heath, JR AF Guzelian, AA Katari, JEB Kadavanich, AV Banin, U Hamad, K Juban, E Alivisatos, AP Wolters, RH Arnold, CC Heath, JR TI Synthesis of size-selected, surface-passivated InP nanocrystals SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SMALL SEMICONDUCTOR CRYSTALLITES; QUANTUM CONFINEMENT; GAAS NANOCRYSTALS; RAMAN-SCATTERING; ELECTRON; MICROCRYSTALS AB Quantum-confined InP nanocrystals from 20 to 50 Angstrom in diameter have been synthesized via the reaction of InCl3 and P(Si(CH3)(3))(3) in trioctylphosphine oxide (TOPO) at elevated temperatures. The nanocrystals are highly crystalline, monodisperse, and soluble in various organic solvents. Improved size distributions have been obtained by size-selectively reprecipitating the nanocrystals. The UV/vis absorption spectra of the particles show the characteristic blue shift of the band gap of up to 1 eV due to quantum confinement, a moderately well-resolved first excitonic excited state, and, in some cases, the resolution of a higher excited state. Structurally, the nanocrystals are characterized with powder X-ray diffraction and transmission electron microscopy. Raman spectroscopy reveals TO and LO modes near the characteristic bulk InP positions as well. a surface mode resulting from finite size. The Raman line widths, line positions, and relative intensities are all size-dependent. X-ray photoelectron spectroscopy (XPS) shows the nanocrystals have a nearly stoichiometric ratio of indium to phosphorus with TOPO surface coverages ranging from 30% to 100%. We have also used XPS to correlate the oxidation of the nanocrystal surface with photoluminescence intensity. Photoluminescence is observed as both band edge and deep trap emission with both features shifting with nanocrystal size. The luminescence is highly dependent on the surface of the nanocrystal with oxidation being a necessary condition for emission. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF LOS ANGELES,DEPT CHEM & BIOCHEM,LOS ANGELES,CA 90095. RI Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 32 TC 353 Z9 357 U1 5 U2 84 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 25 PY 1996 VL 100 IS 17 BP 7212 EP 7219 DI 10.1021/jp953719f PG 8 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300048 ER PT J AU Shkrob, IA Sauer, MC Trifunac, AD AF Shkrob, IA Sauer, MC Trifunac, AD TI High-mobility ions in cyclohexane. A transient absorption study SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID DETECTED MAGNETIC-RESONANCE; ALKANE RADICAL CATIONS; PICOSECOND PULSE-RADIOLYSIS; IRRADIATED CYCLOHEXANE; HYDROCARBON RADIOLYSIS; AROMATIC-HYDROCARBONS; NONPOLAR LIQUIDS; DIMER CATION; FLUORESCENCE; TIME AB Transient absorption kinetics in radiolysis of N2O-saturated cyclohexane has been studied (0.1-100 ns; 300-800 nm). The spectra indicate the involvement of at least three cations (ions I, II, and III), only one of them having abnormally high mobility. Ion II is probably the cyclohexene radical cation, and ion III might be the dimer olefin ion. These two ions absorb as much as ion I at 450-500 nm. While ion II and ion III are scavenged by ethanol and triethylamine with a rate constant of approximate to 10(10) mol(-1) dm(3) s(-1), the scavenging of ion I proceeds with rate constants of approximate to 9 x 10(10) and 2.3 x 10(11) mol(-1) dm(3) s(-1), respectively. The spectrum of ion I is similar to the spectrum of the radical cation of cyclohexane isolated in low-temperature matrices. We were not able to observe the absorption from ion I at delay times longer than 50 ns. A corresponding fast growth of the absorption from solute radical cations of pyrene and perylene was observed. The data (simulated using continuum-diffusion and Monte Carlo approaches) indicate that the scavenging constant is approximate to 4 x 10(11) mol(-1) dm(3) s(-1); the lifetime of the precursor of the aromatic radical cations is approximate to 30 ns. This short lifetime cannot be explained by a reaction with radiolytic products or by homogeneous recombination, and it seems to be incompatible with identification of the long-lived high-mobility ions observed in conductivity experiments as the radical cation of cyclohexane. A mechanism in which the mobile radical cation is in equilibrium with a normally-diffusing ion is examined in an attempt to resolve this conundrum. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 64 TC 22 Z9 22 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 25 PY 1996 VL 100 IS 17 BP 7237 EP 7245 DI 10.1021/jp953255l PG 9 WC Chemistry, Physical SC Chemistry GA UG823 UT WOS:A1996UG82300051 ER PT J AU Baker, RJ VanDenBussche, RA Wright, AJ Wiggins, LE Hamilton, MJ Reat, EP Smith, MH Lomakin, MD Chesser, RK AF Baker, RJ VanDenBussche, RA Wright, AJ Wiggins, LE Hamilton, MJ Reat, EP Smith, MH Lomakin, MD Chesser, RK TI High levels of genetic change in rodents of Chernobyl (Retracted article. See vol 390, pg 100, 1997) SO NATURE LA English DT Article; Retracted Publication ID MUTATIONS AB BASE-PAIR substitution rates for the mitochondrial cytochrome b gene of free-living, native populations of voles collected next to reactor 4 at Chernobyl, Ukraine, were estimated by two independent methods to be in excess of 10(-4) nucleotides per site per generation. These estimates are hundreds of times greater than those typically found in mitochondria of vertebrates, suggesting that the environment resulting from this nuclear power plant disaster is having a measurable genetic impact on the organisms of that region. Despite these DNA changes, vole populations thrive and reproduce in the radioactive regions around the Chernobyl reactor. C1 SAVANNAH RIVER ECOL LAB, AIKEN, SC 29802 USA. INT RES & DEV AGCY, KIEV 252001, UKRAINE. RP Baker, RJ (reprint author), TEXAS TECH UNIV, DEPT BIOL SCI, LUBBOCK, TX 79409 USA. NR 24 TC 49 Z9 51 U1 1 U2 14 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD APR 25 PY 1996 VL 380 IS 6576 BP 707 EP 708 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UG827 UT WOS:A1996UG82700049 PM 8614463 ER PT J AU Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, R Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, J Sung, M Undrus, A White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M Greene, R He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D AF Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, R Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, J Sung, M Undrus, A White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M Greene, R He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D TI A measurement of B(D-0->K-pi(+)pi(0))/B(D-0->K-pi(+)) SO PHYSICS LETTERS B LA English DT Article ID D-MESON DECAYS AB Using a sample of 3.1 fb(-1) integrated luminosity accumulated with the CLEO II detector at the Cornell Electron Storage Ring; we measure the ratio of branching fractions B(D-0 --> K- pi(+)pi(0))/B(D-0 --> K(-)pi(+)) = 3.81 +/- 0.07 +/- 0.26, the most precise determination of this quantity to date. C1 UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,URBANA,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. BINP,RU-630090 NOVOSIBIRSK,RUSSIA. RP Barish, B (reprint author), CALTECH,PASADENA,CA 91125, USA. RI Schaffner, Stephen/D-1189-2011; Britton, David/F-2602-2010; Briere, Roy/N-7819-2014; OI Britton, David/0000-0001-9998-4342; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674; Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900 NR 14 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 25 PY 1996 VL 373 IS 4 BP 334 EP 338 DI 10.1016/0370-2693(96)00159-1 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UJ911 UT WOS:A1996UJ91100012 ER PT J AU Guloy, AM Corbett, JD AF Guloy, AM Corbett, JD TI Synthesis, structure, and bonding of two lanthanum indium germanides with novel structures and properties SO INORGANIC CHEMISTRY LA English DT Article ID MAIN-GROUP ELEMENTS; ZINTL-PHASES; TRANSITION-ELEMENTS; CRYSTAL-STRUCTURE; CLUSTERS; SYSTEM; METALS AB The new tetragonal phases La3In4Ge and La3InGe are obtained from high-temperature reactions of the elements in welded Ta followed by annealing. The structures of both were established by single-crystal X-ray diffraction in tetragonal space group 14/mcm (Z = 4 and 16, a = 8.5165(3) and 12.3083(2) Angstrom, c = 11.9024(4) and 16.0776(4) Angstrom, respectively). La3In4Ge contains layers or slabs of three-connected indium built of puckered 8-rings and 4-rings, or of squashed tetrahedra (''butterflies'') interlinked at all vertices, and these are separated by layers of La and isolated Ge. The phase is deficient of being a Zintl phase by three electrons per formula unit and is better described in terms of an alternate optimized and delocalized bonding picture and an open-shell metallic behavior for the In slabs. The more complex La3InGe, isostructural with Gd3Ga2, is also layered. This phase contains pairs of mixed-occupancy (0.75 In, 0.25 Ge) sites separated by 3.020 Angstrom, as well as isolated In and Ge atoms. The former appear to be fully reduced closed-shell atoms (relative to the bonded Ga dimers in Gd3Ga2) that are held in somewhat close proximity by cation matrix effects. The compound appears to be semiconducting and thus is a classical Zintl phase, (La+3)(3)In-5Ge-4 in the simplest oxidation state notation. High Coulomb energies are presumably important for the nature of the bonding and the stabilities of both compounds. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 37 TC 36 Z9 36 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 24 PY 1996 VL 35 IS 9 BP 2616 EP 2622 DI 10.1021/ic951378e PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UH033 UT WOS:A1996UH03300031 ER PT J AU Hay, BP Zhang, DL Rustad, JR AF Hay, BP Zhang, DL Rustad, JR TI Structural criteria for the rational design of selective ligands .2. Effect of alkyl substitution on metal ion complex stability with ligands bearing ethylene-bridged ether donors SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR MECHANICS CALCULATIONS; CHELATE RING SIZE; COORDINATION CHEMISTRY; MACROCYCLE INTERACTION; AQUEOUS-SOLUTION; CROWN-ETHERS; KINETIC DATA; FORCE-FIELD; NITRATE; CRYSTAL AB A novel approach is presented for the application and interpretation of molecular mechanics calculations in ligand structural design. The methodology yields strain energies that (i) provide a yardstick for the measurement of ligand binding site organization for metal ion complexation and (ii) allow the comparison of any two ligands independent of either the number and type of donor atoms or the identity of the metal ion. Application of this methodology is demonstrated in a detailed examination of the influence of alkyl substitution on the structural organization of ethylene-bridged, bidentate, ether donor ligands for the alkali and alkaline earth cations. Nine cases are examined, including the unsubstituted ethylene bridge (dimethoxyethane), all possible arrangements of individual alkyl groups (monoalkylation, gem-dialkylation, meso-dialkylation, d,l-dialkylation, trialkylation, and tetraalkylation), and both cis and trans attachments of the cyclohexyl group. The calculated degree of binding site organization for metal ion complexation afforded by these connecting structures is shown to correlate with known changes in complex stability caused by alkyl substitution of crown ether macrocycles. RP PACIFIC NW NATL LAB, RICHLAND, WA 99352 USA. NR 46 TC 65 Z9 65 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 EI 1520-510X J9 INORG CHEM JI Inorg. Chem. PD APR 24 PY 1996 VL 35 IS 9 BP 2650 EP 2658 DI 10.1021/ic9514760 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UH033 UT WOS:A1996UH03300037 ER PT J AU Lutz, F Bau, R Wu, P Koetzle, TF Kruger, C Schneider, JJ AF Lutz, F Bau, R Wu, P Koetzle, TF Kruger, C Schneider, JJ TI Neutron diffraction structure analysis of a triply-bridged binuclear cobalt hydride complex, [(eta(5)-Cp*)Co](2)H-3 SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR-STRUCTURE; X-RAY; ATOMS C1 UNIV SO CALIF,DEPT CHEM,LOS ANGELES,CA 90089. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. MAX PLANCK INST KOHLENFORSCH,D-45470 MULHEIM,GERMANY. RI Schneider, Jorg /C-6308-2013 OI Schneider, Jorg /0000-0002-8153-9491 NR 21 TC 16 Z9 16 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 24 PY 1996 VL 35 IS 9 BP 2698 EP 2700 DI 10.1021/ic951297i PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UH033 UT WOS:A1996UH03300047 ER PT J AU WallaceWilliams, SE James, CA deVries, S Saraste, M Lappalainen, P vanderOost, J Fabian, M Palmer, G Woodruff, WH AF WallaceWilliams, SE James, CA deVries, S Saraste, M Lappalainen, P vanderOost, J Fabian, M Palmer, G Woodruff, WH TI Far-red resonance Raman study of copper A in subunit II of cytochrome c oxidase SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PARAMAGNETIC-RESONANCE; CUA SITE; REDUCTASE; PROTEIN; BOND C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. TECH UNIV DELFT,DELFT,NETHERLANDS. EUROPEAN MOLEC BIOL LAB,D-69012 HEIDELBERG,GERMANY. VRIJE UNIV AMSTERDAM,AMSTERDAM,NETHERLANDS. RICE UNIV,HOUSTON,TX 77251. NR 32 TC 37 Z9 37 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 24 PY 1996 VL 118 IS 16 BP 3986 EP 3987 DI 10.1021/ja953646d PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA UG695 UT WOS:A1996UG69500030 ER PT J AU Sarkisov, SS Williams, EK Ila, D Venkateswarlu, P Poker, DB AF Sarkisov, SS Williams, EK Ila, D Venkateswarlu, P Poker, DB TI Vanishing optical isolation barrier in double ion-implanted lithium niobate waveguide SO APPLIED PHYSICS LETTERS LA English DT Article ID WAVE-GUIDES; LINBO3; PROFILES AB Isolation properties at different propagation directions have been studied for an optical barrier between two superposed planar waveguides produced by MeV He+ implantation in LiNbO3. The barrier exists while the modes of the double structure propagate along the optic axis. The spacing between the modes measured with a prism coupler features efficiently isolated waveguides. The barrier ''vanishes'' when the directional angle between an extraordinary wave and the optic axis exceeds 50 degrees. In this case the mode spacing shows strong coupling between the waveguides that makes the double structure similar to a single waveguide with double thickness. (C) 1996 American Institute of Physics. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Sarkisov, SS (reprint author), ALABAMA A&M UNIV,DEPT PHYS,NORMAL,AL 35762, USA. NR 13 TC 13 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 22 PY 1996 VL 68 IS 17 BP 2329 EP 2331 DI 10.1063/1.115847 PG 3 WC Physics, Applied SC Physics GA UF814 UT WOS:A1996UF81400005 ER PT J AU Loretto, D Ross, FM Lucas, CA AF Loretto, D Ross, FM Lucas, CA TI Quasi-one-dimensional CaF2 islands formed on Si(001) by molecular beam epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID CALCIUM-FLUORIDE; GROWTH; SILICON; FILMS AB Quasi-one-dimensional CaF2 islands, 5-10 nm in both width and height and several mu m in length, have been grown on Si(001) by molecular beam epitaxy. Using conventional and high resolution transmission electron microscopy we show that the islands grow in two symmetry-equivalent, {011} orientations and are bounded by {111} facets. The unusual island morphology is attributed to a low density of nucleation sites, the small lattice mismatch, and the anisotropic CaF2 surface energy. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720. RP Loretto, D (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 17 TC 31 Z9 31 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 22 PY 1996 VL 68 IS 17 BP 2363 EP 2365 DI 10.1063/1.115859 PG 3 WC Physics, Applied SC Physics GA UF814 UT WOS:A1996UF81400017 ER PT J AU White, CW Budai, JD Zhu, JG Withrow, SP Aziz, MJ AF White, CW Budai, JD Zhu, JG Withrow, SP Aziz, MJ TI Ion-beam synthesis and stability of GaAs nanocrystals in silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID IMPLANTATION; SILICIDES AB Sequential implantation of Ga and As into silicon followed by thermal annealing has been used to synthesize GaAs buried inside silicon. The GaAs exists in the form of nanocrystals which are three-dimensionally oriented with respect to the silicon matrix. Thermodynamic criteria which are important in determining whether the desired compound will form are discussed. (C) 1996 American Institute of Physics. C1 HARVARD UNIV,CAMBRIDGE,MA 02138. RP White, CW (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 25 TC 32 Z9 33 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 22 PY 1996 VL 68 IS 17 BP 2389 EP 2391 DI 10.1063/1.116143 PG 3 WC Physics, Applied SC Physics GA UF814 UT WOS:A1996UF81400026 ER PT J AU BourretCourchesne, ED AF BourretCourchesne, ED TI Incorporation of hydrogen in nitrogen and arsenic doped ZnSe epitaxial layers grown by organometallic vapor phase epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article AB The incorporation of hydrogen has been investigated using secondary ion mass spectroscopy in arsenic and nitrogen doped ZnSe epitaxial layers grown by organometallic vapor phase epitaxy in a metalhydride free environment. Diisopropylselenide, diethylzinc, tertiarybutylarsine, and tertiarybutylamine were used as precursors. Ammonia was used to provide comparative data for the analysis of the results obtained with tertiarybutylamine. The carrier gas was either hydrogen or nitrogen. The arsenic doped samples grown in nitrogen carrier gas have a low concentration of hydrogen while hydrogen is incorporated in large quantity in samples grown with hydrogen carrier gas. High concentrations of nitrogen are obtained with tertiarybutylamine at low growth temperature and with hydrogen carrier gas. Low concentrations of nitro en are obtained with tertiarybutylamine in presence of nitrogen carrier gas. Hydrogen incorporation is reduced when using tertiarybutylamine instead of ammonia as dopant source. (C) 1996 American Institute of Physics. RP BourretCourchesne, ED (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,CTR ADV MAT 2200,BERKELEY,CA 94720, USA. NR 13 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 APR 22 PY 1996 VL 68 IS 17 BP 2418 EP 2420 DI 10.1063/1.116153 PG 3 WC Physics, Applied SC Physics GA UF814 UT WOS:A1996UF81400036 ER PT J AU Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, SM Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, PP Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, RR Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, JJ Sung, M Undrus, A White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M Greene, R He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S AF Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, SM Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, PP Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, RR Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, JJ Sung, M Undrus, A White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M Greene, R He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S TI Limits on flavor changing neutral currents in D-0 meson Decays SO PHYSICAL REVIEW LETTERS LA English DT Article ID CHARM AB Using the CLEO II detector at the Cornell Electron Storage Ring, we have searched for flavor changing neutral currents and lepton family number violations in D-0 meson decays. The upper limits on the branching fractions for D-0 --> l(+)l(-) and D-0 --> X(0)l(+)l(-) are in the range 10(-5) to 10(-4), where X(0) can be a pi(0), K-s(0), eta, rho(0), omega, (K) over bar(*0) or phi meson, and the l(+)l(-) pair can be e(+)e(-), mu(+)mu(-), or e(+/-)mu(-/+). Although these limits are above the theoretical predictions, most are new or an order of magnitude lower than previous limits. C1 WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. INST PARTICLE PHYS,MONTREAL,PQ,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. INST PARTICLE PHYS,MONTREAL,PQ,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. RP Freyberger, A (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061, USA. RI Schaffner, Stephen/D-1189-2011; Britton, David/F-2602-2010; Briere, Roy/N-7819-2014; OI Britton, David/0000-0001-9998-4342; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674; Poling, Ronald/0000-0001-7305-4702; Bloom, Kenneth/0000-0002-4272-8900 NR 16 TC 35 Z9 36 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 APR 22 PY 1996 VL 76 IS 17 BP 3065 EP 3069 DI 10.1103/PhysRevLett.76.3065 PG 5 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400006 ER PT J AU Abe, F Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Apollinari, G Areti, H Atac, M Auchincloss, P Azfar, F Azzi, P Bacchetta, N Badgett, W Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Bartalini, P Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Bertolucci, S Bhatti, A Biery, K Binkley, M Bird, F Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bortoletto, D Boswell, C Boulos, T Brandenburg, G Bromberg, C BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cen, Y Cervelli, F Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D Cunningham, JD Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demortier, L Denby, B Deninno, M Derwent, PF Devlin, T Dickson, M Dittmann, JR Donati, S Drucker, RB Dunn, A Einsweiler, K Elias, JE Ely, R Engels, E Eno, S Errede, D Errede, S Fan, Q Farhat, B Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fry, A Fuess, TA Fukui, Y FUnaki, S Gagliardi, G Galeotti, S Gallinaro, M Garfinkel, AF Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Goulianos, K Grassmann, H Grewal, A Groer, L GrossoPilcher, C Haber, C Hahn, SR Hamilton, R Handler, R Hans, RM Hara, K Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Heinrich, J CroninHennessy, D Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Hurst, P Huston, J Huth, J Hylen, J Incagli, M Incandela, J Iso, H Jensen, H Jessop, CP Joshi, U Kadel, RW Kajfasz, E Kamon, T Kaneko, T Kardelis, DA Kasha, H Kato, Y Keeble, L Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuhlmann, SE Kuns, E Laasanen, AT Labanca, N Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Loomis, C Long, O Loreti, M Low, EH Lu, J Lucchesi, D Luchini, CB Lukens, P Lys, J Maas, P Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Michail, G Mikamo, S Miller, M Miller, R Mimashi, T Miscetti, S Mishina, M Mitsushio, H Miyashita, S Morita, Y Moulding, S Mueller, J Mukherjee, A Muller, T Musgrave, P Nakae, LF Nakano, I Nelson, CC Neuberger, D NewmanHolmes, C Nodulman, L Ogawa, S Oh, SH Ohl, KE Oishi, R Okusawa, T Pagliarone, C Paoletti, R Papadimitriou, V Park, S Patrick, J Pauletta, G Paulini, M Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Plunkett, R Pondrom, L Produit, N Proudfoot, J Pothos, F Punzi, G Ragan, K Rimondi, F Ristori, L RoachBellino, M Robertson, WJ Rodrigo, T Romano, J Rosenson, L Sakumoto, WK Saltzberg, D Sansoni, A Scarpine, V Schindler, A Schlabach, P Schmidt, EE Schmidt, MP Schneider, O Sciacca, GF Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Sgolacchia, A Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Smith, DA Snider, FD Song, L Song, T Spalding, J Spiegel, L Sphicas, P Spies, A Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Stuart, D Sullivan, G Sumorok, K Swartz, RL Takahashi, T Takikawa, K Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, J Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Tollefson, K Tollestrup, A Tonnison, J deTroconiz, JF Tseng, J Turcotte, M Turini, N Uemura, N Ukegawa, F Unal, G vandenBrink, SC Vejcik, S Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wainer, N Walker, RC Wang, C Wang, CH Wang, G Wang, J Wang, MJ Wang, QF Warburton, A Watts, G Watt, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Westhusing, T Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Wolinski, J Wu, DY Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, S Zhang, W Zucchelli, S AF Abe, F Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Apollinari, G Areti, H Atac, M Auchincloss, P Azfar, F Azzi, P Bacchetta, N Badgett, W Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Bartalini, P Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Bertolucci, S Bhatti, A Biery, K Binkley, M Bird, F Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bortoletto, D Boswell, C Boulos, T Brandenburg, G Bromberg, C BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cen, Y Cervelli, F Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D Cunningham, JD Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demortier, L Denby, B Deninno, M Derwent, PF Devlin, T Dickson, M Dittmann, JR Donati, S Drucker, RB Dunn, A Einsweiler, K Elias, JE Ely, R Engels, E Eno, S Errede, D Errede, S Fan, Q Farhat, B Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fry, A Fuess, TA Fukui, Y FUnaki, S Gagliardi, G Galeotti, S Gallinaro, M Garfinkel, AF Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Goulianos, K Grassmann, H Grewal, A Groer, L GrossoPilcher, C Haber, C Hahn, SR Hamilton, R Handler, R Hans, RM Hara, K Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Heinrich, J CroninHennessy, D Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Hurst, P Huston, J Huth, J Hylen, J Incagli, M Incandela, J Iso, H Jensen, H Jessop, CP Joshi, U Kadel, RW Kajfasz, E Kamon, T Kaneko, T Kardelis, DA Kasha, H Kato, Y Keeble, L Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuhlmann, SE Kuns, E Laasanen, AT Labanca, N Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Loomis, C Long, O Loreti, M Low, EH Lu, J Lucchesi, D Luchini, CB Lukens, P Lys, J Maas, P Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Michail, G Mikamo, S Miller, M Miller, R Mimashi, T Miscetti, S Mishina, M Mitsushio, H Miyashita, S Morita, Y Moulding, S Mueller, J Mukherjee, A Muller, T Musgrave, P Nakae, LF Nakano, I Nelson, CC Neuberger, D NewmanHolmes, C Nodulman, L Ogawa, S Oh, SH Ohl, KE Oishi, R Okusawa, T Pagliarone, C Paoletti, R Papadimitriou, V Park, S Patrick, J Pauletta, G Paulini, M Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Plunkett, R Pondrom, L Produit, N Proudfoot, J Pothos, F Punzi, G Ragan, K Rimondi, F Ristori, L RoachBellino, M Robertson, WJ Rodrigo, T Romano, J Rosenson, L Sakumoto, WK Saltzberg, D Sansoni, A Scarpine, V Schindler, A Schlabach, P Schmidt, EE Schmidt, MP Schneider, O Sciacca, GF Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Sgolacchia, A Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Smith, DA Snider, FD Song, L Song, T Spalding, J Spiegel, L Sphicas, P Spies, A Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Stuart, D Sullivan, G Sumorok, K Swartz, RL Takahashi, T Takikawa, K Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, J Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Tollefson, K Tollestrup, A Tonnison, J deTroconiz, JF Tseng, J Turcotte, M Turini, N Uemura, N Ukegawa, F Unal, G vandenBrink, SC Vejcik, S Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wainer, N Walker, RC Wang, C Wang, CH Wang, G Wang, J Wang, MJ Wang, QF Warburton, A Watts, G Watt, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Westhusing, T Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Wolinski, J Wu, DY Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, S Zhang, W Zucchelli, S TI Measurement of sigma B(W->e nu) and sigma B(Z(0)->e(+)e(-)) in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID = 1.8 TEV; YAN K-FACTOR; P(P)BAR COLLISIONS; PBARP COLLISIONS; RATIO; COLLIDER AB We present a measurement of sigma B(W --> e nu) and sigma B(Z(0) --> e(+)e(-)) in proton-antiproton collisions at root s = 1.8 TeV using a significantly improved understanding of the integrated luminosity. The data represent an integrated luminosity of 19.7 pb(-1) from the 1992-1993 run with the Collider Detector at Fermilab. We find sigma B(W --> e nu) = 2.49 +/- 0.12 nb and sigma B(Z(0) --> e(+)e(-)) = 0.231 +/- 0.012 nb. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV BOLOGNA,IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. BRANDEIS UNIV,WALTHAM,MA 02254. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60637. DUKE UNIV,DURHAM,NC 27708. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV ILLINOIS,URBANA,IL 61801. MCGILL UNIV,INST PARTICLE PHYS,MONTREAL,PQ H3A 2T8,CANADA. UNIV TORONTO,TORONTO,ON M5S 1A7,CANADA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. NATL LAB HIGH ENERGY PHYS,KEK,TSUKUBA,IBARAKI 305,JAPAN. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. OSAKA CITY UNIV,OSAKA 588,JAPAN. UNIV PADUA,IST NAZL FIS NUCL,SEZ PADOVA,I-35131 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PITTSBURGH,PITTSBURGH,PA 15260. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. ROCKEFELLER UNIV,NEW YORK,NY 10021. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. ACAD SINICA,TAIPEI 11529,TAIWAN. SUPERCONDUCTING SUPER COLLIDER LAB,DALLAS,TX 75237. TEXAS A&M UNIV,COLLEGE STN,TX 77843. TEXAS TECH UNIV,LUBBOCK,TX 79409. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. YALE UNIV,NEW HAVEN,CT 06511. RI Warburton, Andreas/N-8028-2013; Kim, Soo-Bong/B-7061-2014; Paulini, Manfred/N-7794-2014; Vucinic, Dejan/C-2406-2008; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012 OI Warburton, Andreas/0000-0002-2298-7315; Paulini, Manfred/0000-0002-6714-5787; Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816 NR 27 TC 64 Z9 64 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3070 EP 3075 DI 10.1103/PhysRevLett.76.3070 PG 6 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400007 ER PT J AU Pisarski, RD AF Pisarski, RD TI Anomalous mesonic interactions near a chiral phase transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOPOLOGICALLY MASSIVE CHROMODYNAMICS; FINITE-TEMPERATURE; GAUGE-THEORIES; HIGHER DIMENSIONS; SCHWINGER MODEL; QCD AB Using constituent quarks coupled to a linear sigma model at nonzero temperature, I show that many anomalous mesonic amplitudes, such as pi(0) --> gamma gamma, vanish in a chirally symmetric phase. Processes which are allowed, such as pi(0) sigma --> gamma gamma, are computed to leading order in a loop expansion. RP Pisarski, RD (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 43 TC 39 Z9 39 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3084 EP 3087 DI 10.1103/PhysRevLett.76.3084 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400010 ER PT J AU Velikovich, AL Dimonte, G AF Velikovich, AL Dimonte, G TI Nonlinear perturbation theory of the incompressible Richtmyer-Meshkov instability SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAYLEIGH-TAYLOR INSTABILITY AB A single-mode nonlinear high-order perturbation theory is developed to describe the Richtmyer-Meshkov instability of an impulsively accelerated interface between an incompressible fluid and a constant supporting pressure. The nonlinear modification of Richtmyer's formula is presented and compared to experimental data with strong radiatively driven shocks, The theory allows a straightforward extension to more general cases of Richtmyer-Meshkov and Rayleigh-Taylor instabilities (multimode, more interfaces, three-dimensional flow, etc.). C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Velikovich, AL (reprint author), BERKELEY SCHOLARS INC,SPRINGFIELD,VA 22150, USA. RI Velikovich, Alexander/B-1113-2009 NR 17 TC 66 Z9 67 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3112 EP 3115 DI 10.1103/PhysRevLett.76.3112 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400017 ER PT J AU Bula, C McDonald, KT Prebys, EJ Bamber, C Boege, S Kotseroglou, T Melissinos, AC Meyerhofer, DD Ragg, W Burke, DL Field, RC HortonSmith, G Odian, AC Spencer, JE Walz, D Berridge, SC Bugg, WM Shmakov, K Weidemann, AW AF Bula, C McDonald, KT Prebys, EJ Bamber, C Boege, S Kotseroglou, T Melissinos, AC Meyerhofer, DD Ragg, W Burke, DL Field, RC HortonSmith, G Odian, AC Spencer, JE Walz, D Berridge, SC Bugg, WM Shmakov, K Weidemann, AW TI Observation of nonlinear effects in compton scattering SO PHYSICAL REVIEW LETTERS LA English DT Article AB Nonlinear Compton scattering has been observed in the collision of a low-emittance 46.6-GeV electron beam with terawatt pulses from a Nd:glass laser at 1054 and 527 nm wavelengths in an experiment at the Final Focus Test Beam at SLAC. Peak laser intensities of 10(18) W/cm(2) have been achieved, corresponding to a value of 0.6 for the parameter eta = eE(rms)/m omega(0)c. Results are presented for multiphoton Compton scattering in which up to four laser photons interact with an electron, in agreement with theoretical calculations. C1 UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP Bula, C (reprint author), PRINCETON UNIV,JOSEPH HENRY LABS,PRINCETON,NJ 08544, USA. RI Horton-Smith, Glenn/A-4409-2011 OI Horton-Smith, Glenn/0000-0001-9677-9167 NR 18 TC 314 Z9 322 U1 3 U2 16 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3116 EP 3119 DI 10.1103/PhysRevLett.76.3116 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400018 ER PT J AU Young, PE Guethlein, G Wilks, SC Hammer, JH Kruer, WL Estabrook, KG AF Young, PE Guethlein, G Wilks, SC Hammer, JH Kruer, WL Estabrook, KG TI Fast ion production by laser filamentation in laser-produced plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAMAN-SCATTERING; LIGHT; EVOLUTION AB Production of protons with energies of similar to 20 keV have been observed to originate from the interaction of a high intensity laser with a preformed underdense plasma. The energy and distribution of ions are explained by acceleration by the ponderomotive force resulting from filamentation. RP Young, PE (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 5508,LIVERMORE,CA 94550, USA. NR 25 TC 27 Z9 28 U1 3 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3128 EP 3131 DI 10.1103/PhysRevLett.76.3128 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400021 ER PT J AU Gog, T Len, PM Materlik, G Bahr, D Fadley, CS SanchezHanke, C AF Gog, T Len, PM Materlik, G Bahr, D Fadley, CS SanchezHanke, C TI Multiple-energy x-ray holography: Atomic images of hematite (Fe2O3) SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHOTOELECTRON HOLOGRAPHY; DIFFRACTION PATTERNS; AUGER-ELECTRON; SCATTERING; RECONSTRUCTION AB Multiple-energy x-ray holography (MEXH) is employed to image the local atomic environment of Fe atoms in hematite. MEXH utilizes synchrotron radiation to generate an interference field within the sample, and then determines the strength of this near field at specific atomic sites from the integrated fluorescence yield. Scanning an extended volume of reciprocal space, the local atomic structure in Fe2O3 is reconstructed by Fourier transformation from the hologram. Image aberrations known to distort single-energy holograms are effectively suppressed by summing data for several incident energies. C1 DESY,HASYLAB,D-22603 HAMBURG,GERMANY. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. LAWRENCE BERKELEY NATL LAB,DIV SCI MAT,BERKELEY,CA 94720. RP Gog, T (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,OAK RIDGE NATL LAB,UPTON,NY 11973, USA. NR 28 TC 202 Z9 206 U1 2 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3132 EP 3135 DI 10.1103/PhysRevLett.76.3132 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400022 ER PT J AU Menchero, JG AF Menchero, JG TI Spin polarization and magnetic circular dichroism in photoemission from the 2p core level of ferromagnetic Ni SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-ABSORPTION; NICKEL; TRANSITION; SPECTRA; METAL; SPECTROSCOPY; ORIGIN AB Spin polarization and magnetic circular dichroism are calculated for angle-resolved photoemission from the 2p core of ferromagnetic Ni. Spin-polarized spectra are found to be in excellent agreement with experimental results. Final-state many body effects are calculated within a periodic-small-cluster scheme. Numerical estimates of the degree of hybridization in the final states are reported, and the spin polarization of the spectrum is explained. The calculated magnetic circular dichroism spectrum exhibits significant strength only in the satellite region. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Menchero, JG (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 29 TC 23 Z9 23 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 22 PY 1996 VL 76 IS 17 BP 3208 EP 3211 DI 10.1103/PhysRevLett.76.3208 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400041 ER PT J AU Butler, WH Zhang, XG Nicholson, DMC Schulthess, TC MacLaren, JM AF Butler, WH Zhang, XG Nicholson, DMC Schulthess, TC MacLaren, JM TI Giant magnetoresistance from an electron waveguide effect in cobalt-copper multilayers SO PHYSICAL REVIEW LETTERS LA English DT Article ID LAYERED MAGNETIC-STRUCTURES; ENHANCED MAGNETORESISTANCE; EXCHANGE AB Calculations of the electrical conductivity and giant magnetoresistance of cobalt-copper multilayers show that these properties can be strongly affected by a waveguide effect. Majority electrons in cobalt have a lower Fermi momentum than in copper. This leads to total internal reflection of electrons whose momentum parallel to the interface exceeds a critical value. This waveguide effect will strongly influence the current distributions in the multilayer if the interfaces are sufficiently smooth, and it will contribute to the giant magnetoresistance if the scattering rates are significantly different in copper and cobalt. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. RP Butler, WH (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 17 TC 59 Z9 59 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 APR 22 PY 1996 VL 76 IS 17 BP 3216 EP 3219 DI 10.1103/PhysRevLett.76.3216 PG 4 WC Physics, Multidisciplinary SC Physics GA UF744 UT WOS:A1996UF74400043 ER PT J AU Saljoughian, M Morimoto, H Than, C Williams, PG AF Saljoughian, M Morimoto, H Than, C Williams, PG TI Tritium labelled alkenes via the Shapiro reaction SO TETRAHEDRON LETTERS LA English DT Article ID METABOLISM AB We report a simple synthesis of a variety of tritiated alkenes with high specific activity. In each case, the trisylhydrazone derivative of the ketone was converted to the vinyllithium intermediate, which was then quenched with high specific activity tritiated water to generate the corresponding tritiated alkene. The specificity of tritium labelling was determined by tritium NMR spectroscopy. (C) 1996 Elsevier Science Ltd C1 LAWRENCE BERKELEY NATL LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. RP Saljoughian, M (reprint author), LAWRENCE BERKELEY NATL LAB,NATL TRITIUM LABELLING FACIL,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 27 TC 4 Z9 4 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD APR 22 PY 1996 VL 37 IS 17 BP 2923 EP 2926 DI 10.1016/0040-4039(96)00448-0 PG 4 WC Chemistry, Organic SC Chemistry GA UG232 UT WOS:A1996UG23200012 ER PT J AU Beach, RJ AF Beach, RJ TI Theory and optimization of lens ducts SO APPLIED OPTICS LA English DT Article DE lens duct; diode end pumping ID LASER-DIODE-ARRAYS; ND-YAG LASER; PUMPED LASER; ONE JOULE; OSCILLATOR AB Lens ducts are simple optical devices that have found application in the coupling of pump radiation from extended two-dimensional semiconductor laser diode arrays into solid-state laser gain media. The operation of these devices relies on the combined effects of lensing at their curved input surface and channeling by total internal reflection off their canted planar sides, to contain and couple semiconductor diode laser light efficiently to the input face of a solid-state laser crystal or glass. The lens duct provides a robust method for amplifying the irradiance of laser diode array pump sources and has made possible a scalable diode end-pumping architecture that offers the opportunity to expand significantly the number of ions and transitions that can be practically engaged in diode-pumped solid-state laser systems. An analytic model that describes the transfer efficiency of lens ducts and aids in the optimization of their design is presented. (C) 1996 Optical Society of America RP Beach, RJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 24 TC 79 Z9 86 U1 1 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1996 VL 35 IS 12 BP 2005 EP 2015 DI 10.1364/AO.35.002005 PG 11 WC Optics SC Optics GA UF393 UT WOS:A1996UF39300010 PM 21085326 ER PT J AU Armstrong, DJ Alford, WJ Raymond, TD Smith, AV AF Armstrong, DJ Alford, WJ Raymond, TD Smith, AV TI Absolute measurement of the effective nonlinearities of KTP and BBO crystals by optical parametric amplification SO APPLIED OPTICS LA English DT Article DE KTP crystals; BBO crystals; second-order nonlinear coefficients ID KTIOPO4; COEFFICIENTS AB Absolute magnitudes of the effective nonlinearity, d(eff), were measured for seven KTP and six BBO crystals. The d(eff)'s were derived from the parametric gain of an 800-nm signal wave in the sample crystals when they were pumped by the frequency-doubled, spatially filtered light from an injection-seeded, Q-switched Nd:YAG laser. The KTP crystals, all type II phase matched with propagation in the X-Z plane, had d(eff) values ranging from 1.97 to 3.50 pm/V. Measurements of gain as a function of phase velocity mismatch indicate that two of the KTP crystals clearly contain multiple ferroelectric domains. For five type I phase-matched BBO crystals, d(eff)-ranged from 1.76 to 1.83 pm/V, and a single type II phase-matched BBO crystal had a d(eff) of 1.56 pm/V. The uncertainty in our measurements of d(eff) values is +/-5% for KTP and +/-10% for BBO. (C) 1996 Optical Society of America RP Armstrong, DJ (reprint author), SANDIA NATL LABS,DEPT LASERS OPT & REMOTE SENSING,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 33 TC 16 Z9 16 U1 0 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1996 VL 35 IS 12 BP 2032 EP 2040 DI 10.1364/AO.35.002032 PG 9 WC Optics SC Optics GA UF393 UT WOS:A1996UF39300015 PM 21085331 ER PT J AU Gill, CG Allen, TM Anderson, JE Taylor, TN Kelly, PB Nogar, NS AF Gill, CG Allen, TM Anderson, JE Taylor, TN Kelly, PB Nogar, NS TI Low-power resonant laser ablation of copper SO APPLIED OPTICS LA English DT Article ID IONIZATION MASS-SPECTROMETRY; PERIODIC SURFACE-STRUCTURE; INDUCED FLUORESCENCE; THERMAL-DESORPTION; POSITIVE-IONS; SPECTROSCOPY; EXCITATION; IRRADIATION; SOLIDS; CU-2 AB We emphasize two points: (1) the properties and mechanisms of very low-fluence ablation of copper surfaces and (2) the sensitivity and selectivity of resonant laser ablation (RLA). We present results for ablation of bulk copper and copper thin films; spot-size effects; the effects of surface-sample preparation and beam polarization; and an accurate measurement of material removal rates, typically less than or equal to 10(-3) Angstrom at 35 mJ/cm(2). Velocity distributions were Maxwellian, with peak velocities approximate to 1-2 x 10(5) cm/s. In addition, we discuss the production of diffractionlike surface features, and the probable participation of nonthermal desorption mechanisms. RLA is shown to be a sensitive and useful diagnostic for studies of low-fluence laser-material interactions. (C) 1996 Optical Society of America C1 UNIV CALIF DAVIS,DEPT CHEM,DAVIS,CA 95616. RP Gill, CG (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,M5 J565,LOS ALAMOS,NM 87545, USA. NR 62 TC 19 Z9 19 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1996 VL 35 IS 12 BP 2069 EP 2082 DI 10.1364/AO.35.002069 PG 14 WC Optics SC Optics GA UF393 UT WOS:A1996UF39300020 PM 21085336 ER PT J AU Dahlem, M Heckman, TM Fabbiano, G Lehnert, MD Gilmore, D AF Dahlem, M Heckman, TM Fabbiano, G Lehnert, MD Gilmore, D TI The hot gaseous halo of the spiral galaxy NGC 3628 in the Leo Triplet SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, halos; galaxies, individual (NGC 3628); radiation mechanisms, thermal; X-rays, galaxies ID X-RAY OBSERVATIONS; GALACTIC NUCLEI; STAR FORMATION; INTERSTELLAR-MEDIUM; RADIO OBSERVATIONS; VLA OBSERVATIONS; MAGNETIC-FIELDS; NGC-3628; M82; EMISSION AB In a 14 ks ROSAT Position Sensitive Proportional Counter pointing we detected an extended (28 x 40 kpc) halo of hot tenuous gas around NGC 3628, with a flat emission distribution and a temperature of T similar or equal to 2 x 10(6) K. The soft X-ray luminosity of the halo gas in the 0.1-2.0 keV band is similar to 8 x 10(39) ergs s(-1) and the total soft X-ray luminosity of NGC 3628 is approximately 2.1 x 10(40) ergs s(-1). The most likely heating source for the halo gas are the shocks resulting from a supernova-driven outflow from the circumnuclear starburst propagating through the halo interstellar medium. Both the morphology and the line ratios of associated optical emission-line gas are consistent with this interpretation. In many respects the soft X-ray halo of NGC 3628 resembles those of other nearby, edge-on starburst galaxies like, e.g., M82 and NGC 253. Its size and radiative cooling time indicate that halos like that of NGC 3628 have to be considered as potentially important contributors to the population of quasi-stellar object absorption-line systems. With two exceptions, most of the compact X-ray sources seen in projection within the halo of NGC 3628 are probably background active galactic nuclei. The remaining two sources might be condensations in the shock-heated halo gas. The soft X-ray properties of a few sources in the disk of NGC 3628 are consistent with those of high-mass X-ray binaries or powerful young supernova remnants. The PSPC spectrum of NGC 3627, which was within the field of view during our observations, also exhibits the typical characteristics of a starburst galaxy. It can be approximated by a power-law + Raymond-Smith model with a total soft X-ray luminosity of L(X) = 1.1 x 10(40) ergs s(-1). C1 JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94551 USA. ESA, DEPT SPACE SCI, DIV ASTROPHYS, NOORDWIJK, NETHERLANDS. RP Dahlem, M (reprint author), SPACE TELESCOPE SCI INST, 3700 SAN MARTIN DR, BALTIMORE, MD 21218 USA. NR 84 TC 57 Z9 57 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1996 VL 461 IS 2 BP 724 EP + DI 10.1086/177097 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UE570 UT WOS:A1996UE57000021 ER PT J AU Woods, DT Klein, RI Castor, JI McKee, CF Bell, JB AF Woods, DT Klein, RI Castor, JI McKee, CF Bell, JB TI X-ray-heated coronae and winds from accretion disks: Time-dependent two-dimensional hydrodynamics with adaptive mesh refinement SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies, active; hydrodynamics; stars, coronae X-rays, galaxies; X-rays, stars ID ACTIVE GALACTIC NUCLEI; NUMERICAL-SIMULATION; CONTINUUM EMISSION; OUTER REGIONS; CATACLYSMIC VARIABLES; VERTICAL STRUCTURE; ANGULAR-MOMENTUM; BINARY-SYSTEMS; BOUNDARY-LAYER; LINE EMISSION AB We perform for the first time time-dependent, two-dimensional, axisymmetric hydrodynamic simulations using local adaptive mesh refinement of thermally driven rotating winds from X-ray-irradiated accretion disks. The disk is assumed to flare in height with radius allowing direct exposure from the central X-ray source. The heating and cooling are treated strictly in the optically thin approximation. We adopt two spectra characteristic of active galactic nuclei (AGNs) which have Compton temperatures of T-IC approximate to 1.3 x 10(7) K and 10(8) K. We have computed a number of models which cover a large range in luminosity (0.002 less than or equal to L/L(Eddington) less than or equal to 1) and radius (less than or similar to 20 Compton radii). Our models enable us to extend and improve on the analytic predictions of Begelman, McKee, & Shields (BMS) for Compton-heated winds by including non-Compton processes such as photoionization heating and line cooling, typical of X-ray-heated winds. These non-Compton processes can be dominant at low temperatures (less than or similar to 10(7) K), thus being important in the wind regions of AGNs. Our results agree well with a number of predictions given by EMS, even when non-Compton processes dominate, suggesting that their analytic approximations of the hydrodynamics of disk winds are applicable to the more general area of X-ray-heated winds. In the regime in which Compton processes dominate (i.e., T-IC = 10(8) K spectrum), we have used our results to improve the analytic predictions of BMS, providing a new expression for the mass-loss rate and a modified view of the wind solution topology. We find that beginning from a basically static state, the time-dependent flow which develops eventually settles into a steady wind, without any evidence of hydrodynamic instabilities. The solution topology consists of a corona with an exponentially truncated wind at small radii, and a vigorous wind at large radii which can be impeded by gravity for small luminosities. We have constructed radius-luminosity parameter space plots of our numerical results in analogy to EMS for both the high and low T-IC, cases, depicting the range of solutions. The plots are strikingly similar to the analytic predictions, especially for high T-IC. We find the radial extent of the corona to be independent of luminosity, as predicted by BMS, extending out to about 0.25R(IC); this is a direct consequence of Compton heating. The transition from an isothermal to nonisothermal corona occurs at a luminosity within about a factor of 2 of the critical luminosity (L(cr) approximate to 0.03T(IC8)(-1/2)L(E)) predicted by BMS. The mass flux density in the corona shows an exponential rise, peaking at around 0.2R(IC) nearly independent of luminosity. The wind solutions can be characterized mainly by steadily heated, free winds (region B in BMS) and gravity-inhibited winds (region C in BMS). Nearly isothermal winds with temperatures of the order T-IC also exist (region A in BMS) but require higher luminosities than was first estimated by BMS. A necessary condition for the winds to approach isothermality is that the luminosity exceed the critical luminosity. The change in wind solutions from regions B and C is characterized by a nearly discontinuous change in the sonic point location from large heights in region C to small heights in region B. The mass-loss rate, however, appears continuous across this boundary. For a streamline leaving the disk surface at a radius R(0), the sonic point distance along the streamline, s(sonic), is such that s(sonic)/R(0) approximate to 0.6 in region B and s(sonic)/R(0) much greater than 1 in region C. An unexpected conclusion from our numerical results is that the area of a flow tube can actually be smaller at the sonic point than at the disk surface. This is because of the presence of an unbalanced radial pressure gradient of the flow at low heights upon being heated. Incorporating this effect into the simple analytical formulae for the mass-loss rate given by EMS yields results which are typically within about a factor of 2 (3) of our numerical results over a wide range of luminosities and radii for the high (low) Compton temperature models. We provide fitting formulae of our numerical results which give the mass flux density as a function of radius and luminosity. We also discuss briefly the implications of our results for the prediction of Fe K alpha lines which have recently been observed in AGNs. C1 UNIV CALIF BERKELEY, SPACE SCI LAB, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. RP LAWRENCE LIVERMORE NATL LAB, POB 808, LIVERMORE, CA 94550 USA. NR 66 TC 80 Z9 81 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1996 VL 461 IS 2 BP 767 EP 804 DI 10.1086/177101 PN 1 PG 38 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UE570 UT WOS:A1996UE57000025 ER PT J AU Li, H Fenimore, EE Liang, EP AF Li, H Fenimore, EE Liang, EP TI Detectability of gamma-ray burst excess toward M31 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (M31); gamma rays, bursts; stars, neutron AB We calculate the expected excess of gamma ray bursts (GRBs) from the direction of M31 assuming that GRBs come from an extended halo around both M31 and our own Galaxy. Specifically, we consider the delayed turn-on and halo-beaming models for GRBs. We express the ratio of GRB rate from M31 to our Galaxy as a function of instrument sensitivities, the observing solid angles toward M31, and the burst luminosity functions. This ratio tends to be much larger than 1 for a small observing angle (<10 degrees) when the instrument can sample close to the distance of M31. Assuming that a hypothetical gamma-ray instrument is 10 times more sensitive than BATSE, we find in a 1 yr observation, for both imaging or nonimaging instruments, that the delayed turn-on model might be tested but no statistically significant signal is expected for the halo-beaming model. Thus, it is extremely difficult to rule out the halo-beaming model by observing M31. C1 RICE UNIV,DEPT SPACE PHYS & ASTRON,HOUSTON,TX 77251. RP Li, H (reprint author), LOS ALAMOS NATL LAB,D436,LOS ALAMOS,NM 87545, USA. NR 17 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1996 VL 461 IS 2 BP L73 EP L77 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UE572 UT WOS:A1996UE57200004 ER PT J AU Ahluwalia, DV AF Ahluwalia, DV TI Theory of neutral particles: McLennan-Case construct for neutrino, its generalization, and a new wave equation SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article AB Continuing our recent argument where we constructed a FNBWW type spin-1 boson having opposite relative intrinsic parity to that of the associated antiparticle, we now study eigenstates of the charge conjugation operator. Based on the observation that if phi(L)(p(mu)) transforms as a (0, j) spinor under Lorentz boosts, then -([j])phi((L))*(p(mu)) transforms as a (j, 0) spinor [with a similar relationship existing between phi(R)(p(mu)) and -([j])phi(R)*(p(mu)); where -([j])J-(-1)([j]) = -J* with -([j]) the well-known Wigner matrix involved in the operation of time reversal] we introduce McLennan-Case type (j, 0) + (0,j) spinors. Relative phases between phi(R)(p(mu)) and -([j])phi(R)*(p(mu)), and phi(L)(p(mu)), turn out to have physical significance and are fixed by appropriate requirements. An explicit construction, and a series of physically relevant properties. for these spinors are obtained for spin-1/2 and spin-1 culminating in the construction of a new wave equation and the introduction of Dirac-like and Majorana-like quantum fields. RP Ahluwalia, DV (reprint author), LOS ALAMOS NATL LAB,MESON PHYS FACIL,GRP P25,MAIL STOP H846,LOS ALAMOS,NM 87545, USA. NR 47 TC 53 Z9 53 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 20 PY 1996 VL 11 IS 10 BP 1855 EP 1874 DI 10.1142/S0217751X96000973 PG 20 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG051 UT WOS:A1996UG05100008 ER PT J AU Kalyuzhnyi, YV Cummings, PT AF Kalyuzhnyi, YV Cummings, PT TI Phase diagram for the Lennard-Jones fluid modelled by the hard-core Yukawa fluid SO MOLECULAR PHYSICS LA English DT Article ID HYPERNETTED-CHAIN EQUATION; ORNSTEIN-ZERNIKE EQUATION; INTEGRAL-EQUATION; CRITICAL-BEHAVIOR; REPULSIVE FORCES; GIBBS ENSEMBLE; SPHERES; COEXISTENCE; SIMULATION; EQUILIBRIA AB The liquid-gas phase diagram for the Lennard-Jones (LJ) fluid model is obtained using the mean spherical approximation (MSA) for the corresponding hard-core Yukawa fluid. The calculated phase diagram is compared with the phase diagrams for the LJ fluid predicted by the Gibbs ensemble Monte Carlo simulation, and by the Percus-Yevick (PY) and reference hypernetted chain (RHNC) theories. The accuracy of the MSA is comparable with the accuracy of the PY approximation. Although the MSA is less accurate than the RHNC approximation, it has an important advantage of being solvable along the whole liquid-gas coexistence curve, including the vicinity of the critical point. C1 UNIV TENNESSEE, DEPT CHEM ENGN, KNOXVILLE, TN 37996 USA. OAK RIDGE NATL LAB, DIV CHEM TECHNOL, OAK RIDGE, TN 37831 USA. RI Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 22 TC 33 Z9 33 U1 1 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0026-8976 EI 1362-3028 J9 MOL PHYS JI Mol. Phys. PD APR 20 PY 1996 VL 87 IS 6 BP 1459 EP 1462 DI 10.1080/00268979650026929 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UJ155 UT WOS:A1996UJ15500016 ER PT J AU Tanaka, S Kern, RS Davis, RF Wendelken, JF Xu, J AF Tanaka, S Kern, RS Davis, RF Wendelken, JF Xu, J TI Vicinal and on-axis surfaces of 6H-SiC(0001) thin films observed by scanning tunneling microscopy SO SURFACE SCIENCE LA English DT Article DE scanning tunneling microscopy; silicon carbide; stepped single crystal surfaces; surface relaxation and reconstruction; surface structure, morphology, roughness, and topography ID MOLECULAR-BEAM EPITAXY; SILICON-CARBIDE; GROWTH; DEPOSITION AB Surfaces of 6H-SiC(0001) homoepitaxial layers deposited on vicinal (similar to 3.5 degrees off (0001) towards [<11(2)over bar 0>]) and on-axis 6H-SiC wafers by chemical vapour deposition have been investigated using ultra-high vacuum scanning tunneling microscopy. Undulating step configurations were observed on both the on-axis and the vicinal surfaces. The former surface possessed wider terraces than the latter. Step heights on both surfaces were similar to 0.25 nm corresponding to single bilayers containing one Si and one C layer. After annealing at T > 1100 degrees C for 3-5 min in UHV, selected terraces contained honeycomb-like regions caused by the transformation to a graphitic surface as a result of Si sublimation. A model of the observed step configuration has been proposed based on the observation of the <(2)over bar 110>] or [<1(2)over bar 10>] orientations of the steps and energetic considerations. Additional deposition of very thin (similar to 2 nm SiC films on the above samples by gas source molecular beam epitaxy was performed to observe the evolution of the surface structure. Step bunching and growth of 6H-SiC layers and formation of 3C-SiC islands were observed on the vicinal and the on-axis surfaces, respectively, and controlled by the diffusion lengths of the adatoms. C1 N CAROLINA STATE UNIV, DEPT MAT SCI & ENGN, RALEIGH, NC 27695 USA. OAK RIDGE NATL LAB, DIV CHEM & ANALYT SCI, OAK RIDGE, TN 37831 USA. RI Davis, Robert/A-9376-2011 OI Davis, Robert/0000-0002-4437-0885 NR 21 TC 23 Z9 23 U1 0 U2 5 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 APR 20 PY 1996 VL 350 IS 1-3 BP 247 EP 253 DI 10.1016/0039-6028(95)01105-6 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA UJ245 UT WOS:A1996UJ24500030 ER PT J AU Phillips, NJ Ziegler, MR Deaven, LL AF Phillips, NJ Ziegler, MR Deaven, LL TI A cDNA from the ovarian cancer critical region of deletion on chromosome 17p13.3 SO CANCER LETTERS LA English DT Article DE ovarian cancer; chromosome 17; tumor suppressor gene ID GENE; LIBRARIES AB Chromosome 17p13.3 is frequently deleted in human ovarian carcinoma, and the 15 kb critical region of deletion may contain a tumor suppressor gene, A 2.3 kb cDNA has been identified which spans 17 kb of genomic DNA, including 8.1 kb within the critical region, and thus is a candidate tumor suppressor gene. This highly conserved gene has significant sequence similarity to a yeast gene of unknown function and to one of the yeast enzymes in the diphthamide synthetic pathway, DPH2, that has a role in global protein synthesis regulation. This gene, named DPH2L (diphthamide biosynthesis protein 2-like), is expressed in multiple tissues and stages of development. C1 LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,DIV LIFE SCI,LOS ALAMOS,NM 87545. RP Phillips, NJ (reprint author), ST LOUIS UNIV,SCH MED,DEPT PATHOL,1402 S GRAND AVE,ST LOUIS,MO 63110, USA. NR 19 TC 29 Z9 32 U1 0 U2 1 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0304-3835 J9 CANCER LETT JI Cancer Lett. PD APR 19 PY 1996 VL 102 IS 1-2 BP 85 EP 90 DI 10.1016/0304-3835(96)04169-9 PG 6 WC Oncology SC Oncology GA UB974 UT WOS:A1996UB97400012 PM 8603384 ER PT J AU Tobiason, JD Rohlfing, EA AF Tobiason, JD Rohlfing, EA TI Lifetimes of vibrational levels in the (B)over-tilde(2)A' state of HCO SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL SURFACES; ELECTRONIC STATES; QUANTUM BEATS; SPECTROSCOPY; ABINITIO; FLUORESCENCE; EXCITATION; SPECTRUM; SYSTEM AB We measure the fluorescence decays for low-lying rotational states in the first eight vibrational levels of HCO (B) over tilde(2)A'. Some long-lived decays exhibit weak quantum beats that we attribute to a higher-order hyperfine perturbation in the B state. We estimate fluorescence quantum yields by combining measured fluorescence intensities and a calculated electronic transition moment. The estimated nonradiative decay rates increase with increasing vibrational excitation and exhibit mode specificity. We discuss possible vibronic coupling mechanisms, including spin-orbit coupling to quartet states and predissociation via the (A) over tilde(2) Pi((2)A '') and (X) over tilde(2)A' states. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. NR 33 TC 11 Z9 11 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 19 PY 1996 VL 252 IS 5-6 BP 333 EP 342 DI 10.1016/0009-2614(96)00163-7 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UJ450 UT WOS:A1996UJ45000007 ER PT J AU Shen, BH Nolan, JP Sklar, LA Park, MS AF Shen, BH Nolan, JP Sklar, LA Park, MS TI Essential amino acids for substrate binding and catalysis of human flap endonuclease 1 SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID DNA-POLYMERASE-I; ESCHERICHIA-COLI; SCHIZOSACCHAROMYCES-POMBE; SACCHAROMYCES-CEREVISIAE; EXCISION-REPAIR; RAD2; GENE; RNA; COMPLEMENTATION; EXONUCLEASE AB Human flap endonuclease 1 (FEN-1) is a member of the structure-specific endonuclease family and is involved in DNA repair, Eight restrictively conserved amino acids in FEN-1 have been converted individually to an alanine to elucidate their roles in specific DNA substrate binding and catalysis. Flap endonuclease activity of the wild type and mutant enzymes was measured by kinetic flow cytometry. Mutants D34A, D86A, and D181A lost their cleavage activity completely but retained substrate binding ability, as measured by their ability to inhibit the wild type enzyme in a competition assay. This indicates that these amino acids contribute to integrity of the enzyme active site. Loss of both binding and cleavage competency for the flap substrate by mutants E156A, G231A, and D233A suggests that these amino acids are involved in substrate binding. Mutants R103A and D179A retained wild type-like enzyme activity. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,NATL FLOW CYTOMETRY RESOURCE,LOS ALAMOS,NM 87545. UNIV NEW MEXICO,SCH MED,DEPT CYTOMETRY,ALBUQUERQUE,NM 87131. NR 30 TC 90 Z9 93 U1 0 U2 6 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 19 PY 1996 VL 271 IS 16 BP 9173 EP 9176 PG 4 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UG044 UT WOS:A1996UG04400001 PM 8621570 ER PT J AU Sajonz, P Zhong, GM Guiochon, G AF Sajonz, P Zhong, GM Guiochon, G TI Influence of the concentration dependence of the mass transfer properties on chromatographic band profiles .2. Accuracy of the determination of isotherm data by frontal analysis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE adsorption isotherms; frontal analysis; equilibrium-dispersive model; band profiles; axial dispersion coefficient, apparent ID LIGHT-SCATTERING; ADSORPTION; DIFFUSION AB Using known relationships between the apparent axial dispersion coefficient and the concentration, the process of isotherm determination by frontal analysis is modeled by calculating numerical solutions of the equilibrium-dispersive model and processing these simulated experimental data using classical methods of frontal analysis. The results show that significant systematic errors can take place when the apparent axial dispersion coefficient depends strongly on the concentration in the range investigated. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ANALYT CHEM,OAK RIDGE,TN 37831. NR 16 TC 37 Z9 39 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 19 PY 1996 VL 731 IS 1-2 BP 1 EP 25 DI 10.1016/0021-9673(95)00988-4 PG 25 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UK387 UT WOS:A1996UK38700001 ER PT J AU Guan, H Guiochon, G AF Guan, H Guiochon, G TI Study of physico-chemical properties of some packing materials .1. Measurements of the external porosity of packed columns by inverse size-exclusion chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE stationary phases, LC; porosity; pore-size distribution; inverse size-exclusion chromatography ID GRADIENT ELUTION CHROMATOGRAPHY; NUCLEAR-MAGNETIC-RESONANCE; ANGLE NEUTRON-SCATTERING; PORE-SIZE; PERFUSION CHROMATOGRAPHY; CATALYTIC CONVERSION; SINGLE-COMPONENT; LARGE MOLECULES; SILICA; DIFFUSION AB Previous work has shown that the beds of packing materials in conventional packed columns consolidate to a marked extent during an initial period. A detailed investigation of this phenomenon requires the development of a procedure for the accurate and precise determination of the external porosity of columns. This data can be obtained by inverse size-exclusion chromatography. We used a series of polystyrene standards with molecular masses ranging from 456 to 20 600 000 and injected them into four series of five chromatographic columns packed with Kromasil, Vydac, YMC, and Zorbax, respectively (all 10-mu m particles of C-18 bonded silica). The internal and external pore volumes (hence, porosities) of the columns can easily be determined with accuracy from the plots of the logarithm of the molecular mass of the probes versus their retention volume. This procedure offers a simple, fast, and convenient method for the determination of the external porosity of columns. This porosity correlates with retention data and equilibrium isotherms. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. NR 79 TC 62 Z9 63 U1 0 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 19 PY 1996 VL 731 IS 1-2 BP 27 EP 40 DI 10.1016/0021-9673(95)01197-8 PG 14 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UK387 UT WOS:A1996UK38700002 ER PT J AU Ohta, K Tanaka, K Fritz, JS AF Ohta, K Tanaka, K Fritz, JS TI Non-suppressed ion chromatography of inorganic anions, magnesium and calcium ions using a pyromellitate eluent and its application in evaluating environmental water quality SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE water analysis; inorganic anions; anions; cations; magnesium; calcium; metal ions; pyromellitate ID PHOTOMETRIC DETECTION; RIVER WATER; CARBONATE; CHLORIDE; SULFATE; NITRATE AB A simple, sensitive and convenient ion chromatographic (IC) method with UV photometric detection using pyromellitate (1,2,4,5-benzenetetracarboxylate)-methanol-water as the eluent on a silica-based anion-exchange column was established for the simultaneous determination of common inorganic anions including HCO3-, Mg2+ and Ca2+ in environmental waters. The anions were detected indirectly, whilst Mg2+ and Ca2+ were detected directly because complexes having strong UV absorption were formed between pyromellitate and these cations. The proposed method was successfully applied to the simultaneous determination of the common anions, Mg2+ and Ca2+ in various river water samples. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP Ohta, K (reprint author), NATL IND RES INST NAGOYA,KITA KU,1-1 HIRATE CHO,NAGOYA,AICHI 462,JAPAN. NR 12 TC 23 Z9 24 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 19 PY 1996 VL 731 IS 1-2 BP 179 EP 186 DI 10.1016/0021-9673(95)01214-1 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UK387 UT WOS:A1996UK38700018 ER PT J AU Iki, N Yeung, ES AF Iki, N Yeung, ES TI Non-bonded poly(ethylene oxide) polymer-coated column for protein separation by capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE poly(ethylene oxide)-coated columns; capillary columns; proteins ID FUSED-SILICA CAPILLARIES; ZONE ELECTROPHORESIS; ISOELECTRIC POINTS; SOLUTE ADSORPTION; PERFORMANCE; EFFICIENCY; PEPTIDES; BUFFERS; ELECTROENDOSMOSIS; ELECTROOSMOSIS AB A simple method to coat a non-ionic hydrophilic polymer onto the inner wall of a bare fused-silica capillary is established. The capillary is first filled with 1 M HCl solution, then flushed with 0.2% poly(ethylene oxide) solution containing 0.1 M HCl, and finally rinsed with the electrophoretic buffer. Each step takes only 5 min. For regeneration of the coating, this procedure is repeated. Four basic proteins were separated by this method around pH 3-7 with phosphate buffer. The separation efficiency in terms of peak shape was excellent compared to bare fused-silica capillaries and comparable to many other more sophisticated column-treatment methods. The reproducibility of migration times of proteins was less than 3% R.S.D. at pH 6 by manual operation of the coating process. Titration of the fused-silica surface with acid and the structure of poly(ethylene oxide) are important factors to form a stable coating via hydrogen bonding to the surface silanol groups. C1 US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RI Iki, Nobuhiko/H-4448-2011 OI Iki, Nobuhiko/0000-0003-4698-4992 NR 44 TC 132 Z9 135 U1 2 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 19 PY 1996 VL 731 IS 1-2 BP 273 EP 282 DI 10.1016/0021-9673(95)01158-7 PG 10 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UK387 UT WOS:A1996UK38700026 ER PT J AU Chen, JB Su, YZ Jacobson, RA Angelici, RJ AF Chen, JB Su, YZ Jacobson, RA Angelici, RJ TI Reactions of the eta(5)-2,5-dimethylthiophene complex Cp*Ir(eta(5)-2,5-Me(2)T)(2+) with nucleophiles (Ph(-), Me(-), (-)CH(CO(2)Me)(2) and OH-) SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE iridium; thiophene; nucleophiles; pentamethylcyclopentadienyl ID COORDINATED THIOPHENE; BASE HYDROLYSIS; BOND-CLEAVAGE; HYDRODESULFURIZATION; REDUCTION; REACTIVITY; BENZENE; LIGAND; SULFUR; ATTACK AB Cp*Ir(eta(5)-2,5-Me(2)T)(2+) (1), where Cp* = eta(5)-C(5)Me(2) and 2,5-Me(2)T = 2,5-dimethylthiophene, reacts with PhLi to give Cp*Ir(2,5-Me(2)T . 2Ph) and the acylthiolate Cp*Ir(eta(4)-SC(3)H(2)MeC(=O)Me) (3) which incorporates oxygen from the tetrahydrofuran solvent and whose structure was established crystallographically. The analogous reaction of 1 with MeLi gives Cp*Ir(2,5-Me(2)T . 2Me). Complex 1 reacts with (CH)-C--(CO(2)Me), to give Cp*Ir(eta(4)-2,5-Me(2)T . C(CO(2)Me)(2)) (6), which contains an opened-ring thiolate ligand. With OH-, 1 gives both 3 and Cp*Ir(eta(4)-2,5-Me(2)T . O) (7), which incorporates a thiophene S-oxide ligand. These reactions are discussed in the context of related reactions of eta(5)-thiophene complexes in the literature. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. CHINESE ACAD SCI,SHANGHAI INST ORGAN CHEM,SHANGHAI 200032,PEOPLES R CHINA. NR 23 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD APR 19 PY 1996 VL 512 IS 1-2 BP 149 EP 156 DI 10.1016/0022-328X(95)06031-Q PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA UN568 UT WOS:A1996UN56800021 ER PT J AU Nagarkatti, M Nagarkatti, PS Brooks, A AF Nagarkatti, M Nagarkatti, PS Brooks, A TI Effect of radon on the immune system: Alterations in the cellularity and functions of T cells in lymphoid organs of mouse SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH LA English DT Article ID ALPHA-PARTICLES; LYMPHOCYTES; MACROPHAGES; ACTIVATION; RESPONSES; ALDICARB; CD44 AB Exposure to radon and its progeny induces significant damage to the cells of the respiratory tract and causes lung cancer. Whether a similar exposure to radon would alter the functions of the immune system has nor been previously investigated. In the current study, we investigated the effect of exposure of C57BL/6 mice to 1000 or 2500 working-level months (WLM) of radon and its progeny by inhalation, on the number and functions of T lymphocytes in lymphoid organs. The control mice received uranium ore dust carrier aerosol by inhalation. Exposure to radon induced marked decrease in the total cellularity of most lymphoid organs such as thymus, peripheral lymph nodes (PLN), and lung-associated lymph nodes (LALN), when compared to the controls. The percentage of T cells increased, while that of non-T cells decreased, in all peripheral lymphoid organs at both the doses of radon. In the thymus, particularly at 2500 WLM of radon exposure, there was a marked decrease in CD4(+)CDB(+) T cells and an increase in the immature CD4(-)CDB(-) T cells. Such alterations in both the numbers and percentages of lymphocytes and macrophages in radon-exposed mice may have resulted from the cell killing by the alpha particles as the immune cells were migrating through the lungs, or it may have been caused by altered migration of cells, inasmuch as expression of CD44, a molecule involved in migration and homing of immune cells, was significantly altered on cells found in different lymphoid organs. In the LALN, where one would predict the largest number of damaged cells to be present, there was a significant decrease in the T-cell responsiveness to mitogens while the B-cell response was not affected. Such alterations may have resulted from the direct effect of alpha-particle exposure on the migrating lymphocytes, altered percentage of lymphocytes as seen in secondary lymphoid organs, or altered expression of adhesion molecules involved in cell activation such as CD44 and CD3. Interestingly, radon exposure caused an increase in the T- and B-cell responsiveness to mitogens in the spleen and PLN. Since there is little evidence of direct radiation dose from radon in lymphoid organs, our studies demonstrating immunological alterations suggest an indirect effect of radon exposure that may have significant repercussions on the development of hypersensitivity and increased susceptibility to infections and cancer in the lung. C1 VIRGINIA POLYTECH INST & STATE UNIV, COLL VET MED, DEPT BIOMED SCI & PATHOBIOL, BLACKSBURG, VA 24061 USA. VIRGINIA POLYTECH INST & STATE UNIV, COLL ARTS & SCI, DEPT BIOL, BLACKSBURG, VA 24061 USA. PACIFIC NW LAB, DEPT BIOL & CHEM, RICHLAND, WA USA. NR 33 TC 16 Z9 19 U1 0 U2 3 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0098-4108 J9 J TOXICOL ENV HEALTH JI J. Toxicol. Environ. Health PD APR 19 PY 1996 VL 47 IS 6 BP 535 EP 552 DI 10.1080/009841096161528 PG 18 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA UG504 UT WOS:A1996UG50400003 PM 8614022 ER PT J AU Zygmunt, SA Curtiss, LA Iton, LE Erhardt, MK AF Zygmunt, SA Curtiss, LA Iton, LE Erhardt, MK TI Computational studies of water adsorption in the zeolite H-ZSM-5 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID AB-INITIO; GAUSSIAN-2 THEORY; BRONSTED ACIDITY; ZSM-5; SITES; ION; CATALYSTS; ENERGIES; ABINITIO; CLUSTER AB Ab initio molecular orbital calculations using Hartree-Fock theory and Moller-Plesset perturbation theory have been used to study the interaction of H2O with the Bronsted acid site in the zeolite H-ZSM-5. Aluminosilicate clusters with up to 28 T atoms (T = Si, Al) were used as models for the zeolite framework. Full optimization of a 3 T atom cluster at the MP2/6-31G(d) level indicates that the ''ion-pair'' structure, Z(-)... HOH2+, formed by proton transfer from the acid site of the zeolite (ZH) to the adsorbed H2O molecule, is a transition state, while the ''neutral'' adsorption structure, ZH ... OH2, is a local energy minimum. Partial optimization of a larger 8 T cluster at the HF/6-31G(d) level also gave results suggesting that the ion-pair structure is a transition state. Calculations were carried out to obtain corrections for high levels of theory, zero-point energies, and larger cluster size. The resulting energy difference between the neutral and ion-pair structure is small (less than 5 kcal/mol and possibly close to zero). The interaction energy of ZH ... OH2 is 13-14 kcal/mol, in agreement with experiment. We find that addition of a second H2O molecule to Z(-)... HOH2+ in the 3 T atom cluster stabilizes the ion-pair structure, Z(-)... H(OH2)(2)(+), making it a local energy minimum. Finally, calculated vibrational frequencies for a 3 T atom cluster are used to help interpret experimental IR absorption spectra. C1 ARGONNE NATL LAB, ARGONNE, IL 60439 USA. VALPARAISO UNIV, DEPT PHYS & ASTRON, VALPARAISO, IN 46383 USA. NR 44 TC 70 Z9 72 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 18 PY 1996 VL 100 IS 16 BP 6663 EP 6671 DI 10.1021/jp952913z PG 9 WC Chemistry, Physical SC Chemistry GA UF879 UT WOS:A1996UF87900046 ER PT J AU Wang, JX Watson, GM Ocko, BM AF Wang, JX Watson, GM Ocko, BM TI Ordered binary ionic adlayers on a Au(110) electrode: Coadsorption of alkali metal cations with iodide anions SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SCANNING TUNNELING MICROSCOPY; DIFFRACTION; ADSORPTION; RECONSTRUCTION; SURFACE AB Alkali metal cations are found, using X-ray diffraction, to coadsorb with iodide ions on a Au(110) electrode surface at potentials positive of the onset of the Au(110) reconstruction and negative of the formation of iodine monolayers. The adlayer exhibits a c(2 x p) in-plane diffraction pattern with p depending on the cation species and concentration. For the CsI adlayer, p = 4/3 independent of potential and the Cs+-I- spacing is close to that in bulk CsI. In KI, NaI, and LiI solutions, p increases with increasing potential. As a result, the coverages of both the cation and anion species decrease with increasing potential. For the anion, the slope of the potential-dependent coverage is opposite of its behavior in the absence of cation coadsorption. This unusual behavior is attributed to the net positive charge within the adlayer due to the partial discharge of chemisorbed iodides. Details of the diffraction features suggest the existence of antiphase domains and relaxation at domain walls. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Wang, JX (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV CHEM SCI,UPTON,NY 11973, USA. RI Wang, Jia/B-6346-2011 NR 26 TC 18 Z9 18 U1 0 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 18 PY 1996 VL 100 IS 16 BP 6672 EP 6677 DI 10.1021/jp952938y PG 6 WC Chemistry, Physical SC Chemistry GA UF879 UT WOS:A1996UF87900047 ER PT J AU McCarthy, MI Peterson, KA Hess, WP AF McCarthy, MI Peterson, KA Hess, WP TI Electronic structure of sodium nitrate: Investigations of laser desorption mechanisms SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SCF METHOD; BASIS-SETS; CONFIGURATION; STATES; NO3 AB This theoretical study uses ab initio quantum mechanical methods to investigate the electronic properties of ground and excited state sodium nitrate. We calculated electronic properties of the crystalline material for bulk, clean, and defected surfaces. The results of these calculations are used to explain the photoexcitation/desorption mechanism and support the conclusions of an earlier experimental investigation of the laser desorption of NO from single-crystal sodium nitrate. Ab initio periodic Hartree-Fock (PHF) theory was used to investigate the ''molecular-ionic'' character of crystalline sodium nitrate. The calculations indicate that the electronic structure of the bulk and cleavage surface are virtually identical (i.e., no shift in the resonant absorption profile is expected). This finding is consistent with the experimental results on the wavelength dependence of NO desorption yields for crystalline NaNO3. However, changes in the absorption manifold are found to accompany the removal of external nitrate oxygens (producing surface nitrite groups). The presence of these chemical defects causes states to appear in the band gap producing a red shift in the absorption band. Complete active space self-consistent field (CASSCF) calculations on NO3-, NO3, and NO2-, support the ''local excitation model'' of the pi*<-- pi(2) transition. These calculations also indicate that the transition energies of the nitrate ion are unaffected by the presence of the surrounding ions. The photoexcitation/dissociation mechanism of the nitrate ions in the crystal, however, differs from gas-phase processes in that the neutral photodetachment channel, observed in the gas phase, is energetically inaccessible in the solid due to the stabilization of ionic species (relative to neutrals) by the crystalline field. RP McCarthy, MI (reprint author), PACIFIC NW NATL LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 34 TC 35 Z9 38 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 18 PY 1996 VL 100 IS 16 BP 6708 EP 6714 DI 10.1021/jp953108n PG 7 WC Chemistry, Physical SC Chemistry GA UF879 UT WOS:A1996UF87900051 ER PT J AU Markovic, NM Gasteiger, HA Philip, N AF Markovic, NM Gasteiger, HA Philip, N TI Oxygen reduction on platinum low-index single-crystal surfaces in alkaline solution: Rotating ring disk(Pt(hkl)) studies SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ADSORPTION; ELECTRODES; KINETICS; HYDROGEN; PT(111) AB The first results of a study of the oxygen reduction reaction on a rotating ring-disk electrode using single-crystal Pt disk electrodes in alkaline solution are presented. The order of activity of Pt(hkl) in 0.1M KOH increased in the sequence (100) < (110) < (111) for both oxygen and peroxide reduction. These differences are attributed to the structure sensitivity of hydroxyl anion (OH.) adsorption on Pt(hkl) and its inhibiting (site blocking) effect on oxygen kinetics. Two different types of OHads occur on Pt(100) and Pt(110), a reversible OHIV, and an irreversible OHir, while only the reversible form is formed on Pt(111). Very small fluxes (I-R/N << 0.011(D)) of peroxide were detected at the ring at potentials where the surfaces have only the reversible form of OHads. More peroxide (I-R/N < 0.03I(D)) was found with the Pt(100) and Pt(110)surfaces in the potential region where irreversible adsorption occurs. The mechanism of O-2 reduction was also affected by adsorbed hydrogen with increased formation of peroxide ions in this potential region; correspondingly, adsorbed hydrogen was found to have an inhibiting effect on peroxide reduction, the effect decreasing in the order (111) > (100) >> (110). RP Markovic, NM (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,MAIL STOP 2-100,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 34 TC 260 Z9 260 U1 12 U2 113 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 18 PY 1996 VL 100 IS 16 BP 6715 EP 6721 PG 7 WC Chemistry, Physical SC Chemistry GA UF879 UT WOS:A1996UF87900052 ER PT J AU Chanowitz, MS AF Chanowitz, MS TI Strong WW scattering in unitary gauge SO PHYSICS LETTERS B LA English DT Article ID STRONG W+W+ SCATTERING; EQUIVALENCE THEOREM; INTERACTING WS; ZS; BOSONS AB A method to embed models of strong WW scattering in unitary gauge amplitudes is presented that eliminates the need for the effective W approximation (EWA) in the computation of cross sections at high energy colliders, The cross sections obtained from the U-gauge amplitudes include the distributions of the final state fermions in ff --> ffWW, which cannot be obtained from the EWA. Since the U-gauge method preserves the interference of the signal and the gauge sector background amplitudes, which is neglected in the EWA, it is more accurate, especially if the latter is comparable to or bigger than the signal, as occurs for instance at small angles because of Coulomb singularities. The method is illustrated for on-shell W+W+ --> W+W+ scattering and for qq --> qqW(+)W(+). RP Chanowitz, MS (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720, USA. NR 23 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 18 PY 1996 VL 373 IS 1-3 BP 141 EP 146 DI 10.1016/0370-2693(96)00120-7 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UH069 UT WOS:A1996UH06900024 ER PT J AU Nelson, DA Duncan, JB Jensen, GA Burton, SD AF Nelson, DA Duncan, JB Jensen, GA Burton, SD TI Isotopomeric water separations with supported polyphosphazene membranes SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE inorganic membranes; composite membranes; ultrafiltration; polyphosphazene; tritiated water ID HEAVY-WATER; PERMEATION; CHEMISTRY; LIGHT AB Poly[bis(phenoxy)phosphazene] and several carboxylated derivatives were examined for use as membranes to separate tritiated water and deuterated water from light water. The polyphosphazenes were solvent cast from dioxane onto a support material of polyethylene terephthalate. These membranes were tested with water containing 10 pCi/ml tritiated water or 10 wt% deuterated water under dead-end filtration conditions. Poly[bis(phenoxy)phosphazene] provided separation of tritiated water up to 31% within the temperature range of 4 to 23 degrees C. The 5 to 10% carboxylated-polyphosphazene membrane shows a tritiated water separation of 43% at 4 degrees C, but the separation approaches zero above approximately 10 degrees C. Membranes with higher carboxyl content (20 and 30%) were much less efficient for tritiated water separation. Under the same low temperature conditions, and with both types of polyphosphazene membranes, deuterated water separation was considerably less efficient. RP Nelson, DA (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 30 TC 10 Z9 10 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD APR 17 PY 1996 VL 112 IS 2 BP 105 EP 113 DI 10.1016/0376-7388(95)00100-X PG 9 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA UF556 UT WOS:A1996UF55600001 ER PT J AU Lian, T Bromberg, SE Yang, H Proulx, G Bergman, RG Harris, CB AF Lian, T Bromberg, SE Yang, H Proulx, G Bergman, RG Harris, CB TI Femtosecond IR studies of alkane C-H bond activation by organometallic compounds: Direct observation of reactive intermediates in room temperature solutions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PHOTOGENERATED CR(CO)5(ROH); TRANSIENT ABSORPTION; OXIDATIVE ADDITION; SPECTROSCOPY; CR(CO)6; PHOTODISSOCIATION; PHOTOCHEMISTRY; COMPLEXES; SOLVATION; KINETICS C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Lian, Tianquan/L-8992-2013 OI Lian, Tianquan/0000-0002-8351-3690 NR 34 TC 63 Z9 63 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 17 PY 1996 VL 118 IS 15 BP 3769 EP 3770 DI 10.1021/ja9541591 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA UF657 UT WOS:A1996UF65700034 ER PT J AU Kane, SM Huntley, DR Gland, JL AF Kane, SM Huntley, DR Gland, JL TI Toluene formation from coadsorbed methanethiol and benzenethiol on the Ni(111) surface SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ADSORPTION; PT(111); H2S C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37381. UNIV MICHIGAN,DEPT CHEM,ANN ARBOR,MI 48109. NR 28 TC 12 Z9 12 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 APR 17 PY 1996 VL 118 IS 15 BP 3781 EP 3782 DI 10.1021/ja953926t PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA UF657 UT WOS:A1996UF65700040 ER PT J AU Wells, M Dermody, DL Yang, HC Kim, T Crooks, RM Ricco, AJ AF Wells, M Dermody, DL Yang, HC Kim, T Crooks, RM Ricco, AJ TI Interactions between organized, surface-confined monolayers and vapor-phase probe molecules .9. Structure/reactivity relationship between three surface-confined isomers of mercaptobenzoic acid and vapor-phase decylamine SO LANGMUIR LA English DT Article ID BENZOIC-ACID; INFRARED-SPECTROSCOPY; VIBRATIONAL-SPECTRA; CYTOCHROME-C; ELECTRODES; GOLD; DERIVATIVES; ADSORPTION; ORIENTATION; CHEMISTRY AB We used Fourier transform infrared external reflectance spectroscopy (FTIR-ERS), nanogravimetry based on thickness-shear-mode resonators (TSMRs), and X-ray photoelectron spectroscopy (XPS) to study self-assembled monolayers (SAMs) of three mercaptobenzoic acid (MBA) isomers on Au and their interactions with vapor-phase decylamine. FTIR-ERS spectra of the 4-, 3-, and 2-MBA SAMs indicate that the proximity of the carboxylic acid group to the Au substrate surface affects the electronic environment of the benzene ring and the acidity of the carboxyl-group proton. TSMR results show that reaction of 4-, 3-, and 2-MBA monolayers with vapor-phase decylamine probe molecules results in decylamine fractional surface coverages of 0.97, 0.83, and 0.45 of the theoretical monolayer maximum, respectively. The gravimetric results are corroborated by in-situ FTIR-ERS difference spectra of the MBA monolayers obtained during reaction with decylamine, which show the simultaneous disappearance of carbonyl and hydroxyl bands and appearance of carboxylate and aliphatic hydrocarbon bands. XPS results show that increasing the proximity of the carboxyl group to the surface results in a relative increase in the proportion of carboxyl-group oxygen that is in the 531.0 eV electron binding energy state compared to the 532.5 eV state, indicating a change of chemical environment for oxygen. The overall results are consistent with a model involving proton transfer from the SAM to the vapor-phase bases wherein acid strength depends on the accessibility of the donor group, and they demonstrate a clear structure/reactivity correlation for surface-confined isomers, which illustrates the dramatic constraints imposed by surface-induced ordering compared to anisotropic bulk-phase reactivity. C1 TEXAS A&M UNIV,DEPT CHEM,COLLEGE STN,TX 77843. SANDIA NATL LABS,MICROSENSOR RES & DEV DEPT,ALBUQUERQUE,NM 87185. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 50 TC 69 Z9 72 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 17 PY 1996 VL 12 IS 8 BP 1989 EP 1996 DI 10.1021/la9507951 PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA UF822 UT WOS:A1996UF82200009 ER PT J AU Song, X Miura, M Xu, X Taylor, KK Majumder, SA Hobbs, JD Cesarano, J Shelnutt, JA AF Song, X Miura, M Xu, X Taylor, KK Majumder, SA Hobbs, JD Cesarano, J Shelnutt, JA TI Langmuir-Blodgett films of stearic acid containing octakis((methoxycarbonyl)methyl)-meso-tetrakis(((eicosanyloxy)carbonyl)p henyl)porphyrin SO LANGMUIR LA English DT Article ID RESONANCE RAMAN-SPECTRA; N-15 SUBSTITUTED DERIVATIVES; PORPHYRIN FORCE-FIELD; NICKEL OCTAETHYLPORPHYRIN; MOLECULAR-STRUCTURE; MONOLAYERS; ASSIGNMENTS; ORIENTATION; HEMOGLOBIN; COMPLEXES AB Molecular mechanics calculations are coupled with a knowledge of properties of porphyrins in solution and available synthetic strategies to computer-designed a lipoporphyrin, [2,3,7,8,12,13,17,18-octakis-((methoxycarbonyl)methyl)-5,10,15,20-tetrakis(((eicosanyloxy)carbonyl)phenyl)porphrin] (LipoP), for future electron-transfer studies and biosensor applications. To prevent separation of the porphyrin and stearic acid phases in the films, the head group was chosen on the basis of earlier studies that showed that its nickel(II) derivative does not pi-pi aggregate in aqueous solution. The lack of aggregation of the porphyrin unit results from the high degree of nonplanarity of the macrocycle and the steric constraints of the twelve bulky peripheral acid substituents. Nonpolar tails consisting of 20-carbon long linear alkanes were attached to the head group to anchor the LipoP head group into the stearic acid films. Metal derivatives of LipoP have been synthesized and characterized by NMR, resonance Raman, and UV-visible spectroscopic methods. Also, the solubility and solution aggregation properties of LipoP were investigated. Finally, Langmuir films of the Ni derivative of LipoP in stearic acid (Sh) (and for comparison also films of nickel protoporphyrin dimethyl ester (PPDME) in SA) were fabricated and characterized by pressure-area isotherms and then transferred as Langmuir-Blodgett (LB) films onto glass or silicon substrates. These NiLipoP-SA and NiPPDME-SALB films were characterized by spectroscopic methods. Resonance Raman spectra show that NiLipoP does not pi-pi aggregate in the films, unlike NiPPDME. Molecular mechanics calculations of the interactions between NiLipoP, a stearic acid monolayer, and surrounding water molecules support a structural interpretation of the spectral and physical properties of the NiLipoP-SA films that locates the porphyrin head group outside of the hydrophobic region of the films while remaining anchored into the film by the four attached hydrocarbon chains. C1 SANDIA NATL LABS,FUEL SCI DEPT,ALBUQUERQUE,NM 87185. SANDIA NATL LABS,CERAM PROC SCI DEPT,ALBUQUERQUE,NM 87185. UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RI Shelnutt, John/A-9987-2009 OI Shelnutt, John/0000-0001-7368-582X NR 40 TC 28 Z9 29 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 17 PY 1996 VL 12 IS 8 BP 2019 EP 2027 DI 10.1021/la950762l PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA UF822 UT WOS:A1996UF82200013 ER PT J AU Behm, JM Lykke, KR Pellin, MJ Hemminger, JC AF Behm, JM Lykke, KR Pellin, MJ Hemminger, JC TI Projection photolithography utilizing a Schwarzschild microscope and self-assembled alkanethiol monolayers as simple photoresists SO LANGMUIR LA English DT Article C1 ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. UNIV CALIF IRVINE,DEPT CHEM,IRVINE,CA 92717. UNIV CALIF IRVINE,INST SURFACE & INTERFACE SCI,IRVINE,CA 92717. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 22 TC 42 Z9 42 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 17 PY 1996 VL 12 IS 8 BP 2121 EP 2124 DI 10.1021/la950811u PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA UF822 UT WOS:A1996UF82200029 ER PT J AU Decatur, SM Franzen, S DePillis, GD Dyer, RB Woodruff, WH Boxer, SG AF Decatur, SM Franzen, S DePillis, GD Dyer, RB Woodruff, WH Boxer, SG TI Trans effects in nitric oxide binding to myoglobin cavity mutant H93G SO BIOCHEMISTRY LA English DT Article ID MOLECULAR STEREOCHEMISTRY; PROXIMAL HISTIDINE; RESONANCE RAMAN; LIGAND-BINDING; HEME; NITROSYLMETALLOPORPHYRINS; HEMOGLOBIN; CLEAVAGE; BOND; NO AB When nitric oxide (NO) binds to heme proteins, it exerts a repulsive trans effect on the proximal ligand, resulting in weakening or rupture of the proximal ligand-iron bond. The general question of whether NO binding generates a five-coordinate complex with proximal ligand release is important for the function of enzymes such as guanylate cyclase. This question can be addressed by studying NO binding to the myoglobin cavity mutant H93G, where the proximal histidine has been replaced by glycine. When this protein is expressed in the presence of imidazole (Im), an imidazole molecule occupies the proximal cavity and serves as a ligand to the iron [Barrick, D. (1994) Biochemistry 33, 6546-6554]. This proximal imidazole can be exchanged for a variety of exogenous ligands [DePillis, G. D., Decatur, S. M., Barrick, D., & Boxer, S. G. (1994) J. Am. Chem. Soc. 116, 6981-6982]. While CO binds to H93G(Im) to form a stable six-coordinate complex similar to that of the wild type and NO binds to wild-type myoglobin to form a six-coordinate complex, we find that the binding of NO to H93G(Im) under similar conditions results in the cleavage of the exogenous imidazole-iron bond at neutral pH, leaving a five-coordinate heme-NO complex, H93G-NO, inside the protein. When a large excess of imidazole is added to this five-coordinate NO complex, a six-coordinate complex can be formed; thus, the binding constant of a sixth ligand to the five-coordinate H93G-NO complex can be measured. This is found to be several orders of magnitude smaller than the binding constant of Im to the carbonmonoxy, deoxy, or the metcyano forms of the protein. By replacement of Im with methyl-substituted imidazoles which have hindered or strained binding conformations, this binding constant can be reduced further and some of the factors responsible for favoring the five-coordinate form can be elucidated. Thus, the cavity mutant H93G provides a novel model system for studying the factors that control the coordination state of NO complexes of heme proteins and serves as a bridge between synthetic heme model complexes in simple solvents and site-directed mutants in the structured environment found in proteins. C1 STANFORD UNIV,DEPT CHEM,STANFORD,CA 94350. LOS ALAMOS NATL LAB,BIOSCI & BIOTECHNOL GRP,LOS ALAMOS,NM 87545. FU NIGMS NIH HHS [GM27738] NR 36 TC 68 Z9 68 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 16 PY 1996 VL 35 IS 15 BP 4939 EP 4944 DI 10.1021/bi951661p PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UF521 UT WOS:A1996UF52100034 PM 8664286 ER PT J AU Ogo, S Chen, H Olmstead, MM Fish, RH AF Ogo, S Chen, H Olmstead, MM Fish, RH TI Aqueous organometallic chemistry .2. H-1 NMR spectroscopic, synthetic, and structural study of the chemo- and diastereoselective reactions of [Cp*Rh-(H2O)(3)](2+) with nitrogen ligands as a function of pH SO ORGANOMETALLICS LA English DT Article ID (ETA-5-PENTAMETHYLCYCLOPENTADIENYL)RHODIUM AQUA COMPLEX; PENTAMETHYLCYCLOPENTADIENYL-IRIDIUM COMPLEXES; BIOORGANOMETALLIC CHEMISTRY; RHODIUM; NUCLEOBASE; DERIVATIVES AB The reactions of a new Cp*Rh aqua synthon, [Cp*Rh(H2O)(3)](2+) (1), at acidic pH values (2-6) with aniline (2), pyridine (3), and L-phenylalanine (4) have provided interesting chemo- and diastereoselectivities as studied by: H-1 NMR, FAB/MS, and single-crystal X-ray crystallography. The reaction of 2 and aqua complex 1, at pH values from 4 to 6, quantitatively provided [Cp*Rh(eta(6)-aniline)](2+) (5); the structure of 5 was unequivocally determined by a;single-crystal X-ray analysis, which also showed an approximate 25% eta(5) component. Compound 3 reacted with 1, at pH 2-6, to selectively provide [Cp*Rh(eta(1)-pyridine)(n)(H2O)(3-n)](2+) (n = 1-3) complexes 6a-c as a function of pH. Surprisingly, complex 1 reacted with 4, from pH 4 to 6, to provide only one diastereomer of the known cyclic trimer [(Cp*Rh)(mu-eta(1)-(OCO):eta(2)-(N,OCO)-L-phenylalanine)] (3+)(3) (7; S-C,S-C,S-C,S-Rb,S-Rh,S-Rh), an example of a one-step, highly diastereoselective reaction in H2O. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF DAVIS,DEPT CHEM,DAVIS,CA 95616. NR 16 TC 35 Z9 35 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD APR 16 PY 1996 VL 15 IS 8 BP 2009 EP 2013 DI 10.1021/om950681k PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA UF984 UT WOS:A1996UF98400009 ER PT J AU Roelofs, TA Liang, WC Latimer, MJ Cinco, RM Rompel, A Andrews, JC Sauer, K Yachandra, VK Klein, MP AF Roelofs, TA Liang, WC Latimer, MJ Cinco, RM Rompel, A Andrews, JC Sauer, K Yachandra, VK Klein, MP TI Oxidation states of the manganese cluster during the flash-induced S-state cycle of the photosynthetic oxygen-evolving complex SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID X-RAY ABSORPTION; PHOTOSYSTEM-II; SPECTROSCOPY; EVOLUTION; WATER; TEMPERATURE; APPARATUS; IONS AB The Mn K-edge x-ray absorption spectra for the pure S states of the tetranuclear Mn cluster of the oxygen-evolving complex of photosystem II during flash-induced S-state cycling have been determined. The relative S-state populations in samples given 0, 1, 2, 3, 4, or 5 flashes were determined from fitting the flash-induced electron paramagnetic resonance (EPR) multiline signal oscillation pattern to the Kok model. The edge spectra of samples given 0, 1, 2, or 3 flashes were combined with EPR information to calculate the pure S-state edge spectra. The edge positions (defined as the zero-crossing of the second derivatives) are 6550.1, 6551.7, 6553.5, and 6553.8 eV for S-0, S-1, S-2, and S-3, respectively. In addition to the shift in edge position, the S-0 --> S-1 and S-1 --> S-2 transitions are accompanied by characteristic changes in the shape of the edge, both indicative of Mn oxidation. The edge position shifts very little (0.3 eV) for the S-2 --> S-3 transition, and the edge shape shows only subtle changes. We conclude that probably no direct Mn oxidation is involved in this transition. The proposed Mn oxidation state assignments are as follows: S-0 (II, III, IV, IV) or (III, III, III, IV), SI (III, III, IV, IV), S-2 (III, IV, IV, IV), S-3 (III, IV, IV, IV). C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP Roelofs, TA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,STRUCT BIOL DIV,BERKELEY,CA 94720, USA. NR 28 TC 164 Z9 164 U1 2 U2 15 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 APR 16 PY 1996 VL 93 IS 8 BP 3335 EP 3340 DI 10.1073/pnas.93.8.3335 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UF740 UT WOS:A1996UF74000035 PM 11607649 ER PT J AU Boudreau, N Werb, Z Bissell, MJ AF Boudreau, N Werb, Z Bissell, MJ TI Suppression of apoptosis by basement membrane requires three-dimensional tissue organization and withdrawal from the cell cycle SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID EXTRACELLULAR-MATRIX; DIFFERENTIATION; GROWTH; EXPRESSION; INVOLUTION AB The basement membrane (BM) extracellular matrix induces differentiation and suppresses apoptosis in mammary epithelial cells, whereas cells lacking BM lose their differentiated phenotype and undergo apoptosis, Addition of purified BM components, which are known to induce beta-casein expression, did not prevent apoptosis, indicating that a more complex BM was necessary. A comparison of culture conditions where apoptosis would or would not occur allowed us to relate inhibition of apoptosis to a complete withdrawal from the cell cycle, which was observed only when cells acquired a three-dimensional alveolar structure in response to BM, In the absence of this morphology, both the G(1) cyclin kinase inhibitor p21/WAF-1 and positive proliferative signals including c-myc and cyclin D1 were expressed and the retinoblastoma protein (Rb) continued to be hyperphosphorylated, When we overexpressed either c-myc in quiescent cells or p21 when cells were still cycling, apoptosis was induced. In the absence of three-dimensional alveolar structures, mammary epithelial cells secrete a number of factors including transforming growth factor alpha and tenascin, which when added exogenously to quiescent cells induced expression of c-myc and interleukin-beta 1-converting enzyme (ICE) mRNA and led to apoptosis, These experiments demonstrate that a correct tissue architecture is crucial for long-range homeostasis, suppression of apoptosis, and maintenance of differentiated phenotype. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. UNIV CALIF SAN FRANCISCO,RADIOBIOL & ENVIRONM HLTH LAB,SAN FRANCISCO,CA 94143. FU NCI NIH HHS [CA 57621] NR 34 TC 203 Z9 207 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 16 PY 1996 VL 93 IS 8 BP 3509 EP 3513 DI 10.1073/pnas.93.8.3509 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UF740 UT WOS:A1996UF74000067 PM 8622967 ER PT J AU Bash, PA Ho, LL MacKerell, AD Levine, D Hallstrom, P AF Bash, PA Ho, LL MacKerell, AD Levine, D Hallstrom, P TI Progress toward chemical accuracy in the computer simulation of condensed phase reactions SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID POTENTIAL FUNCTIONS; COMBINED QUANTUM; DYNAMICS; MOLECULES; LYSOZYME; MODELS; WATER AB We describe a procedure for the generation of chemically accurate computer-simulation models to study chemical reactions in the condensed phase, The process involves (i) the use of a coupled semiempirical quantum and classical molecular mechanics method to represent solutes and solvent, respectively; (ii) the optimization of semiempirical quantum mechanics (QM) parameters to produce a computationally efficient and chemically accurate QM model; (iii) the calibration of a quantum/classical microsolvation model using nb initio quantum theory; and (iv) the use of statistical mechanical principles and methods to simulate, on massively parallel computers, the thermodynamic properties of chemical reactions in aqueous solution, The utility of this process is demonstrated by the calculation of the enthalpy of reaction in vacuum and free energy change in aqueous solution for a proton transfer involving methanol, methoxide, imidazole, and imidazolium, which are functional groups involved with proton transfers in many biochemical systems, An optimized semiempirical QM model is produced, which results in the calculation of heats of formation of the above chemical species to within 1.0 kcal/mol (1 kcal = 4.18 kJ) of experimental values, The use of the calibrated QM and microsolvation QM/MM (molecular mechanics) models for the simulation of a proton transfer in aqueous solution gives a calculated free energy that is within 1.0 kcal/mol (12.2 calculated vs, 12.8 experimental) of a value estimated from experimental pKa values of the reacting species. C1 YALE UNIV,DEPT PHYS,JW GIBBS LAB,NEW HAVEN,CT 06511. ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. UNIV MARYLAND,SCH PHARM,DEPT PHARMACEUT SCI,BALTIMORE,MD 21230. RP Bash, PA (reprint author), ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. OI MacKerell, Alex/0000-0001-8287-6804 NR 31 TC 85 Z9 85 U1 0 U2 11 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 APR 16 PY 1996 VL 93 IS 8 BP 3698 EP 3703 DI 10.1073/pnas.93.8.3698 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UF740 UT WOS:A1996UF74000102 PM 11607654 ER PT J AU Ingram, JC Groenewold, GS Appelhans, AD Dahl, DA Delmore, JE AF Ingram, JC Groenewold, GS Appelhans, AD Dahl, DA Delmore, JE TI Detection limit and surface coverage determination for tributyl phosphate on soils by static SIMS SO ANALYTICAL CHEMISTRY LA English DT Article ID ION MASS-SPECTROMETRY AB The minimum detectable limit (MDL) and semiquantitative determination of surface coverages of tributyl phosphate (TBP) on soils by static SIMS are reported. Two soils with similar bulk chemistries having surface areas of 3 and 20 m(2)/g were exposed to TBP (solution-phase and gas-phase exposures). These samples were investigated using two SIMS instruments, one utilizing a quadrupole mass analyzer and the other an ion trap mass analyzer. The SIMS response plotted as a function of exposure exhibited a leveling of the signal at a surface concentration estimated at 1 monolayer. The overall results of these studies were similar for both solution- and gas-phase exposures and for both soils. A minimum detection limit for TBP on both soils was determined to be 0.06 +/- 0.03 monolayer (similar to 70 pg/mm(2)) for the quadrupole SIMS. Preliminary results suggest that the MDL for TBP analysis on soils using ion trap SIMS is lower; however, because the ion trap SIMS is still evolving, the MDL for that instrument was not determined. These results provide a basis for evaluation of static SIMS for use as a screening tool and illustrate the potential for investigating submonolayer surface coverages of organic contaminants on environmental surfaces by static SIMS. RP Ingram, JC (reprint author), IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 21 TC 29 Z9 30 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 15 PY 1996 VL 68 IS 8 BP 1309 EP 1316 DI 10.1021/ac9505841 PG 8 WC Chemistry, Analytical SC Chemistry GA UE566 UT WOS:A1996UE56600005 ER PT J AU Adams, DP Mayer, TM Swartzentruber, BS AF Adams, DP Mayer, TM Swartzentruber, BS TI Selective area growth of metal nanostructures SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPE; SURFACE; METALLIZATION; DEPOSITION; ADSORPTION; SI(100) AB Nanometer-scale metal lines are fabricated onto Si(100) substrates by scanning tunneling microscope (STM) based lithography and subsequent chemical vapor deposition. An STM tip is first used to define areas for metal layer growth by electron stimulated desorption of adsorbed hydrogen. Exposure to Fe(CO)(5) at 275 degrees C results in preferential deposition of Fe onto Si dangling bond sites (i.e., depassivated areas defined by the STM tip), while the monohydride resist remains intact in surrounding areas. Fe metal lines with widths similar to 10 nm are constructed using this selective-area, autocatalytic growth technique. RP Adams, DP (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 27 TC 47 Z9 47 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 15 PY 1996 VL 68 IS 16 BP 2210 EP 2212 DI 10.1063/1.115861 PG 3 WC Physics, Applied SC Physics GA UE761 UT WOS:A1996UE76100014 ER PT J AU Zolper, JC Shul, RJ Baca, AG Wilson, RG Pearton, SJ Stall, RA AF Zolper, JC Shul, RJ Baca, AG Wilson, RG Pearton, SJ Stall, RA TI Ion-implanted GaN junction field effect transistor SO APPLIED PHYSICS LETTERS LA English DT Article AB Selective area ion implantation doping has been used to fabricate GaN junction field effect transistors (JFETs). p-type and n-type doping was achieved with Ca and Si implantation, respectively, followed by a 1150 degrees C rapid thermal anneal. A refractory W gate contact was employed that allows the p-gate region to be self-aligned to the gate contact. A gate turn-on voltage of 1.84 V at 1 mA/mm of gate current was achieved. For a similar to 1.7 mu mx50 mu m JFET with a -6 V threshold voltage, a maximum transconductance of 7 mS/mm at V-GS = -2V and saturation current of 33 mA/mm at V-GS = 0 V were measured. These results were limited by excess access resistance be expected to be improved with optimized n(+) implants in the source and drain regions. (C) 1996 American Institute of Physics. C1 HUGHES RES LABS,MALIBU,CA 90265. UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611. EMCORE CORP,SOMERSET,NJ 08873. RP Zolper, JC (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 16 TC 137 Z9 141 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 15 PY 1996 VL 68 IS 16 BP 2273 EP 2275 DI 10.1063/1.115882 PG 3 WC Physics, Applied SC Physics GA UE761 UT WOS:A1996UE76100035 ER PT J AU Smith, BB Nozik, AJ AF Smith, BB Nozik, AJ TI Study of electron transfer at semiconductor liquid interfaces addressing the full system electronic structure SO CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; TRANSFER RATES; CHEMISORPTION; MODELS; WATER AB We present new models and simulations for electron transfer (ET) at the semiconductor-liquid interface. Apparently for the first time, we present ''first principles'' molecular dynamics simulations of this interface which address its full electronic structure (a water/InP/Fe(H2O)(6)(2+/3+) ET system is primarily addressed). Our formalism is capable of describing in detail the semiconductor/liquid/redox species system and its real world complications. The shortcomings of conventional models are clearly highlighted. We also report a new Anderson Hamiltonian based ET theory (ABETT) model which includes full energy dependence. We relate our ABETT to molecular orbital theory, compare it to simulation results, and reexamine other ABE?Ts in light of our findings. We view many fundamental physical features of our models as new. Many are entirely unaccounted for in conventional models of the semiconductor-liquid interface. Our results have quite general implications for solid-liquid interface ET. RP Smith, BB (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 32 TC 21 Z9 21 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD APR 15 PY 1996 VL 205 IS 1-2 BP 47 EP 72 DI 10.1016/0301-0104(95)00315-0 PG 26 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UE282 UT WOS:A1996UE28200006 ER PT J AU Lingle, RL Ge, NH Jordan, RE McNeill, JD Harris, CB AF Lingle, RL Ge, NH Jordan, RE McNeill, JD Harris, CB TI Femtosecond studies of electron tunneling at metal-dielectric interfaces SO CHEMICAL PHYSICS LA English DT Article ID IMAGE-POTENTIAL STATES; 2-PHOTON PHOTOEMISSION; RYDBERG STATES; SURFACES; DYNAMICS; ENERGY; FILMS AB Femtosecond time-resolved two-photon photoemission spectroscopy (TPPE) has been used to measure the lifetimes of image potential electrons at alkane mono- and bilayers on Ag(111). The n = 1 lifetimes for zero, one, and two layers of n-heptane on Ag(111) are 32 +/- 10 fs, 155 +/- 20 fs, and 1580 +/- 200 fs, respectively, This approximately exponential increase in lifetime is consistent with a tunneling picture in which the adlayer forms a barrier that slows the decay of an image potential electron back into the metal. The existence of the tunneling barrier is consistent with the repulsive electron affinity of the longer chain n-alkanes in the condensed phase. The lifetimes of the higher quantum states indicate that the presence of the monolayer significantly reduces coupling of the image states to the bulk band structure, so that further changes in lifetime are determined by the adlayer barrier and an attempt rate related to the classical oscillation time in the modified image potential well. These results are compared with quantitative predictions of a model by Cole which considers the tunneling barrier presented by the layer and the effect of the layer on the attempt rate. These results are considered in the context of previous TPPE studies of metal-insulator interfaces. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. EO LAWRENCE BERKELEY NATL LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI McNeill, Jason/E-5389-2011 NR 29 TC 102 Z9 102 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD APR 15 PY 1996 VL 205 IS 1-2 BP 191 EP 203 DI 10.1016/0301-0104(95)00375-4 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UE282 UT WOS:A1996UE28200015 ER PT J AU Smith, BB Halley, JW Nozik, AJ AF Smith, BB Halley, JW Nozik, AJ TI On the Marcus model of electron transfer at immiscible liquid interfaces and its application to the semiconductor liquid interface SO CHEMICAL PHYSICS LA English DT Article ID TRANSFER RATES; DYNAMICS; ABINITIO AB We report calculations for electron transfer rates at immiscible liquid interfaces with new models closely related to a model originally developed by R.A. Marcus. We compare our modified models both with the original Marcus model and with an adaptation of it by N.S. Lewis to electron transfer at the semiconductor-liquid interface. On the basis of these comparisons and a thorough examination of the foundations of both the Marcus and Lewis models, we find no basis for the assertion in the literature that the Lewis model can be used to calculate an upper limit for the electron transfer rate constant at the semiconductor-liquid interface. Features we discuss of the Lewis model and a related model by H. Gerischer show that these semiconductor-liquid interface ET models are evidently not physically plausible. We also conclude that while the Marcus model appears to be a physically plausible first order model for immiscible liquid systems, in its present form it does not seem that it can produce reliable quantitative estimates for real liquid-liquid systems. Our enhancements, both suggested and implemented here, of the Marcus model appear to offer the potential for constructing augmented and better defined models for immiscible liquid ET. C1 UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. RP Smith, BB (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 44 TC 30 Z9 30 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD APR 15 PY 1996 VL 205 IS 1-2 BP 245 EP 267 DI 10.1016/0301-0104(95)00393-2 PG 23 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UE282 UT WOS:A1996UE28200019 ER PT J AU Maudlin, PJ Schiferl, SK AF Maudlin, PJ Schiferl, SK TI Computational anisotropic plasticity for high-rate forming applications SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID FINITE; INTEGRATION; ALGORITHM; ROTATION; TEXTURE AB Constitutive models and solution algorithms for anisotropic elastoplastic material strength are developed for use in high-rate explicit multi-dimensional continuum mechanics codes. The constitutive modeling is posed in an unrotated material frame using the polar decomposition theorem. Continuous quadratic and discontinuous piecewise yield functions obtained from polycrystal simulations for metallic hexagonal-close-packed and cubic crystal structures are utilized. Associative flow formulations incorporating these yield functions are solved using various solution algorithms; explicit, semi-implicit and geometric normal return schemes are assessed for stability, accuracy and efficiency. Isotropic scaling (hardening) of the anisotropic yield surface shapes is included in the modeling. An explosive forming application involving large strain was selected to investigate the effect of using anisotropic materials. Axisymmetric two-dimensional forming simulations were performed for both crystal structures producing resultant formed shapes that are unique to the material's initial yield anisotropy, and are distinct from isotropic results. RP LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 39 TC 24 Z9 24 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 EI 1879-2138 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD APR 15 PY 1996 VL 131 IS 1-2 BP 1 EP 30 DI 10.1016/0045-7825(95)00983-3 PG 30 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA UR441 UT WOS:A1996UR44100001 ER PT J AU Ding, JZ McGrath, WJ Sweet, RM Mangel, WF AF Ding, JZ McGrath, WJ Sweet, RM Mangel, WF TI Crystal structure of the human adenovirus proteinase with its 11 amino acid cofactor SO EMBO JOURNAL LA English DT Article DE catalytic triad; convergent evolution; cysteine proteinase; peptide cofactor; viral proteinase ID SUBSTRATE; PEPTIDE; TYPE-2; POLYPEPTIDE; PAPAIN AB The three-dimensional structure of the human adenovirus-2 proteinase complexed with its 11 amino acid cofactor, pVIc, was determined at 2.6 Angstrom resolution by X-ray crystallographic analysis. The fold of this protein has not been seen before. However, it represents an example of either subtly divergent or powerfully convergent evolution, because the active site contains a Cys-His-Glu triplet and oxyanion hole in an arrangement similar to that in papain. Thus, the adenovirus proteinase represents a new, fifth group of enzymes that contain catalytic triads, pVIc, which extends a beta-sheet in the main chain, is distant from the active site, yet its binding increases the catalytic rate constant 300-fold for substrate hydrolysis. The structure reveals several potential targets for antiviral therapy. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. FU NIAID NIH HHS [AI26049] NR 38 TC 94 Z9 96 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0261-4189 J9 EMBO J JI Embo J. PD APR 15 PY 1996 VL 15 IS 8 BP 1778 EP 1783 PG 6 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA UG748 UT WOS:A1996UG74800003 PM 8617222 ER PT J AU Moldwin, MB Thomsen, MF Bame, SJ McComas, DJ Weiss, LA Reeves, GD Belian, RD AF Moldwin, MB Thomsen, MF Bame, SJ McComas, DJ Weiss, LA Reeves, GD Belian, RD TI The appearance of plasmaspheric plasma in the outer magnetosphere in association with the substorm growth phase SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOSYNCHRONOUS ORBIT; ELECTRIC-FIELDS; MECHANISMS; REGIONS; MODEL AB Short intervals (<2.5 hrs) of dense (greater than or equal to 10 cm(-3)), cold (less than or equal to 10 eV) plasmaspheric plasma are observed at synchronous orbit in association with the growth phase of geomagnetic substorms. We interpret the strong correlation between these phenomena in terms of the reconfiguration of the duskside/nightside magnetosphere during the growth phase of geomagnetic substorms. This reconfiguration moves plasmaspheric plasma outward to synchronous orbit, occasionally even in the midnight region. C1 LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,LOS ALAMOS,NM 87545. RI Moldwin, Mark/F-8785-2011; Reeves, Geoffrey/E-8101-2011 OI Moldwin, Mark/0000-0003-0954-1770; Reeves, Geoffrey/0000-0002-7985-8098 NR 24 TC 11 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1996 VL 23 IS 8 BP 801 EP 804 DI 10.1029/95GL03663 PG 4 WC Geosciences, Multidisciplinary SC Geology GA UF439 UT WOS:A1996UF43900003 ER PT J AU Henderson, MG Murphree, JS AF Henderson, MG Murphree, JS TI Viking observations of a reverse convection cell developing in response to a northward turning of the interplanetary magnetic field SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POLAR-CAP; MODEL; IMF; PERTURBATIONS AB Observations of a developing reverse convection cell on September 23, 1986 are examined using auroral images acquired with the UV imager on board the Viking Spacecraft. The cell possesses a counter-clockwise rotational sense and evolves on the duskside of the northern auroral distribution between the duskside oval and a complex duskside transpolar are system. As the structure evolves, it grows and appears to displace the transpolar are toward the dawn. We interpret these observations in terms of a model proposed by Burch et al., [1992] in which open field lines produced by merging on the high latitude magnetopause produce reverse convection cells between the oval and the transpolar arcs associated with horse-collar or teardrop auroral patterns. C1 UNIV CALGARY,DEPT PHYS & ASTRON,CALGARY,AB T2N 1N4,CANADA. RP Henderson, MG (reprint author), LOS ALAMOS NATL LAB,DIV NON PROLIFERAT & INT SECUR,MAIL STOP D436,LOS ALAMOS,NM 87545, USA. RI Henderson, Michael/A-3948-2011 OI Henderson, Michael/0000-0003-4975-9029 NR 14 TC 0 Z9 0 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1996 VL 23 IS 8 BP 809 EP 812 DI 10.1029/96GL00619 PG 4 WC Geosciences, Multidisciplinary SC Geology GA UF439 UT WOS:A1996UF43900005 ER PT J AU Li, SP Eastman, JA Newnham, RE Cross, LE AF Li, SP Eastman, JA Newnham, RE Cross, LE TI Susceptibility of nanostructured ferroelectrics SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE dielectric permittivity; ferroelectric phase transition; thin films ID PHASE-TRANSITIONS; LANDAU THEORY; SURFACE; SUPERLATTICES; FILMS; MODES AB The onset of long-range order in the size-driven ferroelectric phase transition has been discussed extensively by use of mean field theory in the literature. In order to prevent erroneous analysis of the dielectric permitivity of nanometric sized ferroelectrics, we present a pertinent description of the dielectric susceptibility of nanostructured ferroelectrics within the context of Landau-Ginzburg theory. Consequently, we also discuss the influence of size on the dielectric permittivity of thin films and relevant implications. C1 PENN STATE UNIV,MAT RES LAB,UNIVERSITY PK,PA 16802. RP Li, SP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Eastman, Jeffrey/E-4380-2011 NR 35 TC 13 Z9 13 U1 0 U2 2 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD APR 15 PY 1996 VL 35 IS 4B BP L502 EP L504 DI 10.1143/JJAP.35.L502 PG 3 WC Physics, Applied SC Physics GA UM422 UT WOS:A1996UM42200013 ER PT J AU Fullerton, EE Adenwalla, S Felcher, G Sowers, CH Bader, SD Robertson, JL Berger, A AF Fullerton, EE Adenwalla, S Felcher, G Sowers, CH Bader, SD Robertson, JL Berger, A TI Suppression of biquadratic coupling at the Cr Neel temperature in Fe/Cr(001) superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. RI Bader, Samuel/A-2995-2013; Fullerton, Eric/H-8445-2013; Berger, Andreas/D-3706-2015 OI Fullerton, Eric/0000-0002-4725-9509; Berger, Andreas/0000-0001-5865-6609 NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4524 EP 4524 DI 10.1063/1.361769 PN 2A PG 1 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700010 ER PT J AU Kawakami, RK EscorciaAparicio, EJ Qiu, ZQ AF Kawakami, RK EscorciaAparicio, EJ Qiu, ZQ TI Magnetic coupling in Co/face-centered-cubic Fe/Co sandwiches SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID EPITAXIAL FE; EXCHANGE; OSCILLATIONS; CU(100); LAYERS; PERIOD AB Ferromagnetic (FC) and antiferromagnetic coupling (AFC) of Co layers across a metastable fee Fe spacer layer has been observed. Room-temperature-grown Fe on Co/Cu(100) was chosen as a spacer layer because it exhibits three distinct structural and magnetic phases depending on the thickness range: fct and ferromagnetic (region I), fee and nonferromagnetic (region II), bcc and ferromagnetic (region III) (listed in order of increasing thickness). Co/Fe/Co sandwiches were grown on Cu(100) by molecular beam epitaxy with a base pressure of similar to 2x10(-10) Ton, and characterized by low-energy electron diffraction and reflection high-energy electron diffraction. The magnetic properties were studied in situ using surface magneto;optic Ken effect. Using a wedged Fe spacer layer, we investigated the magnetic coupling between Co films across many thicknesses of Fe. We found FC in region I, strong AFC at the boundary between regions I and II, and weak AFC in region II. We also studied the effect of just the Co overlayer on the metastable fee Fe. We find that Co/Fe/Cu(100) differs qualitatively from Fe/Co/Cu(100). Finally, we find an oscillation in the AFC with a periodicity of similar to 12 Angstrom by artificially increasing the thickness range of region II. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Kawakami, RK (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Qiu, Zi Qiang/O-4421-2016 OI Qiu, Zi Qiang/0000-0003-0680-0714 NR 13 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4532 EP 4534 DI 10.1063/1.361714 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700014 ER PT J AU Hundley, MF Neumeier, JJ Heffner, RH Jia, QX Wu, XD Thompson, JD AF Hundley, MF Neumeier, JJ Heffner, RH Jia, QX Wu, XD Thompson, JD TI Transport and magnetism correlations in thin-film ferromagnetic oxides SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID MAGNETORESISTANCE AB To determine the T-c dependence of the colossal magnetoresistance (CMR) exhibited by the ferromagnetic La(0.7)A(0.3)MnO(3+delta) (A=Ba, Ca, Sr) system, we examine the magnetic-field and temperature-dependent resistivity and magnetization of a series of thin films that were grown via pulsed-laser deposition. The films had magnetic ordering temperatures (T-c) ranging from 150 to 350 K. All samples display a large negative MR that is largest near T-c, and samples with a low T-c display significantly larger MR values than do samples with large T-c's. The quantity rho(T-c)/rho(4 K), the amount by which the resistivity is reduced by full ferromagnetic order, varies as exp(E(a)/T-c) with an activation energy E(a)=0.1 eV. These results indicate that the magnitude of the CMR effect in a given specimen is controlled not by rho(T-c), but by T-c via the ratio rho(T-c)/rho(4 K). Phenomenological scaling relationships are also reported that link rho(H, T) to both H and M(H, T). (C) 1996 American Institute of Physics. RP Hundley, MF (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. RI Jia, Q. X./C-5194-2008 NR 14 TC 30 Z9 30 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4535 EP 4537 DI 10.1063/1.361715 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700015 ER PT J AU Roder, H Stolze, J Silver, RN Muller, G AF Roder, H Stolze, J Silver, RN Muller, G TI Spin correlation functions in random-exchange s=1/2 XXZ chains SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID DISORDER AB The decay of (disorder-averaged) static spin correlation functions at T = 0 for the one-dimensional spin-1/2 XXZ antiferromagnet with uniform longitudinal coupling J Delta and random transverse coupling J lambda(i) is investigated by numerical calculations for ensembles of finite chains, At Delta = 0 (XX model) the calculation is based on the Jordan-Wigner mapping to free lattice fermions for chains with up to N = 100 sites. At Delta not equal 0 Lanczo diagonalizations are carried out for chains with up to N = 22 sites. The longitudinal correlation function [(S0Srz)-S-z] is found to exhibit a power-law decay with an exponent that varies with Delta and, for nonzero Delta, also with the width of the lambda(i)-distribution. The results for the transverse correlation function [(S0Srx)-S-x] show a crossover from power-law decay to exponential decay as the exchange disorder is turned on. (C) 1996 American Institute of Physics. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV RHODE ISL,DEPT PHYS,KINGSTON,RI 02881. UNIV DORTMUND,INST PHYS,W-4600 DORTMUND,GERMANY. RP Roder, H (reprint author), UNIV BAYREUTH,INST PHYS,D-95440 BAYREUTH,GERMANY. NR 8 TC 7 Z9 7 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4632 EP 4634 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700056 ER PT J AU Chaiken, A Michel, RP Wang, CT AF Chaiken, A Michel, RP Wang, CT TI Magnetic properties of epitaxial and polycrystalline Fe/Si multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID SUPERLATTICES AB Fe/Si multilayers with antiferromagnetic interlayer coupling have been grown via ion-beam sputtering on both glass and single-crystal substrates. High-angle x-ray diffraction measurements show that both sets of films have narrow Fe peaks, implying a large crystallite size and crystalline iron silicide spacer layers. Low-angle x-ray diffraction measurements show that films grown on glass have rougher interfaces than those grown on single-crystal substrates. The multilayers grown on glass have a larger remanent magnetization than the multilayers grown on single-crystal substrates. The observation of magnetocrystalline anisotropy in hysteresis loops and (hkl) peaks in x-ray diffraction demonstrates that the films grown on MgO and Ge are epitaxial. The smaller remanent magnetization in Fe/Si multilayers with better layering suggests that the remanence is not an intrinsic property. (C) 1996 American Institute of Physics. C1 STANFORD UNIV,DEPT MAT SCI & ENGN,PALO ALTO,CA 94305. RP Chaiken, A (reprint author), LAWRENCE LIVERMORE NATL LAB,MAT SCI & TECHNOL DIV,LIVERMORE,CA 94551, USA. NR 13 TC 12 Z9 12 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4772 EP 4774 DI 10.1063/1.361926 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700106 ER PT J AU Michel, RP Chaiken, A Wall, MA Dykes, JW Ankner, JF Kaiser, H AF Michel, RP Chaiken, A Wall, MA Dykes, JW Ankner, JF Kaiser, H TI Anomalous temperature dependence of interlayer coupling in Fe/Si multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 NATL INST STAND & TECHNOL,BOULDER,CO 80303. UNIV MISSOURI,COLUMBIA,MO 65211. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 3 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4775 EP 4775 DI 10.1063/1.361861 PN 2A PG 1 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700107 ER PT J AU Sternlieb, BJ Hill, JP Inami, T Shirane, G Lee, WT Werner, SA Fawcett, E AF Sternlieb, BJ Hill, JP Inami, T Shirane, G Lee, WT Werner, SA Fawcett, E TI Critical dynamics at the spin-density-wave transition of chromium SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB Neutron scattering measurements of the critical fluctuations associated with the spin-density-wave transition at the Neel temperature, T-N approximate to 312 K, in a single-Q chromium crystal are reported. Critical fluctuations are observed emanating from allowed magnetic satellite positions and from satellite positions, corresponding to absent magnetic domains, at which no elastic scattering occurs. The inelastic scattering from these ''silent satellites'' grows rapidly with increasing temperature, becoming equal to the allowed single-Q satellite scattering at T-N. The line shapes of the inelastic scattering at both the allowed and silent satellites are found to be intrinsically asymmetric, reflecting the underlying nesting geometry of the Fermi surface. Energy scans at the silent satellite positions reveal a weakly temperature dependent, characteristic energy below which the observed scattering intensity falls rapidly to zero. (C) 1996 American Institute of Physics. C1 UNIV MISSOURI,DEPT PHYS,COLUMBIA,MO 65211. UNIV TORONTO,DEPT PHYS,TORONTO,ON M5S 1A7,CANADA. RP Sternlieb, BJ (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. RI Hill, John/F-6549-2011 NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4802 EP 4804 DI 10.1063/1.361677 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700118 ER PT J AU Fishman, RS Liu, SH AF Fishman, RS Liu, SH TI Goldstone modes of incommensurate chromium alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID SPIN-DENSITY-WAVE; MAGNETIC EXCITATIONS; PHASE AB The spin excitations about the two incommensurate wavevectors of the spin-density-wave (SDW) state in Cr are studied for the first time within the random-phase approximation. Transverse spin-wave (SW) moabs and longitudinal phason modes are associated with the rotational and translational symmetries of Cr. While both mode frequencies vanish at the SDW ordering wavevectors, only the SW mode with linear dispersion and mode velocity c=v(F)/root 3 is undamped for nonzero frequencies. As in a local-moment system, the SW mode corresponds to the rigid rotation of the local magnetic moments. The phason modes have a nearly linear dispersion at low frequencies with velocity c(ph)10 nm in width. The thicker grain boundaries are Nd-rich, while the thinner grain boundaries in the hot-pressed sample exhibit an Fe-rich composition near that of the NdFe3 phase. Nd-rich phases are found at the grain boundary junctions of both samples, with the Nd:Fe ratio near 7:3 in the die-upset sample, and up to 3:2 in the hot-pressed sample. The significance of the microstructure and the grain boundary phases on the magnetic behavior in the two samples is discussed. (C) 1996 American Institute of Physics. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP Nguyen, TD (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720, USA. NR 18 TC 10 Z9 10 U1 3 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4848 EP 4850 DI 10.1063/1.361630 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700136 ER PT J AU EscorciaAparicio, EJ Kawakami, RK Qiu, ZQ AF EscorciaAparicio, EJ Kawakami, RK Qiu, ZQ TI Structural and magnetic properties of face-centered-cubic Fe films grown on Co(100) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID EPITAXIAL FE; CU(100); FE/CU(100) AB A rich variety of magnetic and structural properties; have been found in fee Fe films grown on Cu(100). In order to better comprehend the relation between the magnetic and structural properties of fee Fe, we investigated fee Fe films grown by molecular beam epitaxy on fee Co(100). Structural characterization by low-energy electron diffraction and reflection high-energy electron diffraction indicate that the structural properties of fcc Fe films grown on Co(100) at room temperature are very similar to those of fee Pe on Cu(100), exhibiting three distinct regions (fct, fee, and bcc), with characteristic reconstructions at the boundaries. Magnetic measurements with in situ surface magneto-optic Ken effect (SMOKE) reveal in-plane magnetization at room temperature for the three regions. Regions I and III are ferromagnetic, while region II has a small Ken signal which is constant throughout the region. Cusps in the coercivity of the SMOKE loops are found to correspond to transitions between the three regions. Oxygen absorption experiments performed at room temperature revealed no change in the magnetization of region II, suggesting that the live layers responsible for the magnetic signal in this region are not at the surface. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP EscorciaAparicio, EJ (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Qiu, Zi Qiang/O-4421-2016 OI Qiu, Zi Qiang/0000-0003-0680-0714 NR 9 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4964 EP 4966 DI 10.1063/1.361922 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700179 ER PT J AU Tischer, M May, F Baberschke, K Hjortstam, O Arvanitis, D Dunn, JH Trygg, J Johansson, B Eriksson, O Wills, JM AF Tischer, M May, F Baberschke, K Hjortstam, O Arvanitis, D Dunn, JH Trygg, J Johansson, B Eriksson, O Wills, JM TI Enhancement of orbital magnetism at surfaces: Co on Cu(100) SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 UNIV UPPSALA,DEPT PHYS,S-75121 UPPSALA,SWEDEN. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. FREE UNIV BERLIN,INST EXPTL PHYS,D-14195 BERLIN,GERMANY. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 2 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 4983 EP 4983 DI 10.1063/1.361611 PN 2A PG 1 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700187 ER PT J AU Moon, RM AF Moon, RM TI Magnetic scattering of neutrons SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. NR 0 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 APR 15 PY 1996 VL 79 IS 8 BP 5022 EP 5022 DI 10.1063/1.361562 PN 2A PG 1 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700205 ER PT J AU Suh, BJ Borsa, F Miller, LL Johnston, DC Torgeson, DR Corti, M AF Suh, BJ Borsa, F Miller, LL Johnston, DC Torgeson, DR Corti, M TI Evidence for crossover effects in the spin dynamics of the two-dimensional antiferromagnet Sr2CuO2Cl2 from Cl-35 nuclear magnetic resonance SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB Cl-35 nuclear magnetic resonance (NMR) and relaxation measurements have been performed in stacked Sr2CuO2Cl2 single crystals with Neel temperature T-N = 257 K for two crystal orientations with respect to the applied field: H parallel to c and H perpendicular to c. All the parameters of Cl-35 NMR are found to exhibit a strong orientation dependence varying in temperature. In particular, the unconventional anisotropy and strong temperature dependence of the Cl-35 nuclear spin-spin relaxation rate, T-2(-1), are presented and discussed in terms of a crossover of the Cu2+ spin dynamics from Heisenberg to XY-like correlation for T --> TNN+. The onset of anisotropic broadening and shift of the Cl-35 NMR line was observed well above T-N, which is in agreement with the previous results. (C) 1996 American Institute of Physics. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. UNIV PAVIA,DIPARTIMENTO FIS A VOLTA,INFM,I-27100 PAVIA,ITALY. RP Suh, BJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 9 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5084 EP 5086 DI 10.1063/1.361581 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700227 ER PT J AU Krishnan, KM Modak, AR Lucas, CA Michel, R Cherry, HB AF Krishnan, KM Modak, AR Lucas, CA Michel, R Cherry, HB TI Role of epitaxy and polycrystallinity in the magnetoresistance and magnetization of La0.8Sr0.2MnO3 thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB La0.8Sr0.2MnO3 thin films were simultaneously deposited by pulsed laser ablation on silicon (Si) and LaAlO3 (LAG) substrates. Films on Si were polycrystalline while those on LAO were (100) epitaxial with an in-plane correlation length of approximate to 10 nn. The magnetization and magnetoresistance behavior of these two films were significantly different. Both films exhibit antiferromagnetic ferromagnetic transitions-at different temperatures [180 K (LAG); 230 K (Si)]-and their magnetic moments at 10 K were significantly different (Si-0.0035 emu; LAO-0.0022 emu). However, both films showed significant high field slope in magnetization at 10 K. Significant fractions of both films remain antiferromagnetic at low temperatures and hence net susceptibilities, dependent on the direction of the applied magnetic field, are different for the epitaxial (LAG) and randomly oriented polycrystalline (Si) films. The magnetoresistance peak, corresponding to the semiconductor-metal transition is observed at 170 and 130 K for the epitaxial (LAG) and polycrystalline (Si) films, respectively. Moreover, their resistance values are two orders of magnitude different (Si-MOhms; LAO-KOhms). These properties can be interpreted in terms of the major role of grain boundaries in determining the scattering as well as possible differences in O-2 stoichiometry. (C) 1996 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. UNIV CALIF BERKELEY,BERKELEY,CA 94720. RP Krishnan, KM (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 10 TC 24 Z9 24 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5169 EP 5171 DI 10.1063/1.361919 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700261 ER PT J AU Butler, WH Zhang, XG Nicholson, DMC Schulthess, TC MacLaren, JM AF Butler, WH Zhang, XG Nicholson, DMC Schulthess, TC MacLaren, JM TI First principles calculations of electrical conductivity and giant magnetoresistance of periodic multilayers and spin valves SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB We used the Layer Korringa Kohn Rostoker technique to calculate the electronic structure of cobalt-copper multilayers and spin valves from first principles within the local spin density approximation. Using this electronic structure together with a phenomenological self-energy which may vary from layer to layer, we calculated the non-local layer-dependent conductivity by means of the Kubo linear response formalism. By calculating the majority the minority conductivities for parallel and anti-parallel alignment of the moments in the cobalt layers we determined the giant magnetoresistance (GMR). Several interesting features emerge from the calculations, When the scattering rates are relatively high, we find that the contributions to the GMR are largely non-local, with the largest contributions arising from changes in the currents carried in a cobalt plane next to copper due to fields sensed in the cobalt layer on the other side of copper. When scattering rates are relatively low (comparable to that of cobalt and copper at room temperature), there are important contributions to the GMR from local conduction in the copper layers. This effect arises from the fact that when the component of the majority spin electron momentum parallel to the layers exceeds a certain value, it gets trapped in the copper layers. If the scattering rate is lower in the copper than in the cobalt there is a significant enhancement in the majority spin conductivity and in the GMR. This effect if analogous to the channeling of light by an optical waveguide. (C) 1996 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. RP Butler, WH (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 14 TC 5 Z9 5 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5282 EP 5287 DI 10.1063/1.362566 PN 2A PG 6 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700303 ER PT J AU Brewer, MA Krishnan, KM Ortiz, C AF Brewer, MA Krishnan, KM Ortiz, C TI Epitaxial Fe16N2 films grown on Si(001) by reactive sputtering SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID NITROGEN-IMPLANTATION; IRON FILMS; MAGNETIZATION AB We present a crystallographic template for the growth of the range of Fe-N phases on Si(001) by lattice matching on selected underlayers. Epitaxial films of pure alpha-Fe, gamma'-Fe4N, and alpha'-Fe8N (N martensite) were grown individually by the optimization of reactive Nz Sputtering parameters. The orientation relation of the Fe-N phases was FeN(001)\\Ag(001)\\Si(001) and Fe-N[100]\\Ag[110]\\Si[100]. Annealing the alpha'-Fe8N films resulted in the formation of alpha'-Fe8N/alpha ''-Fe16N2 mixtures. In addition to the crystallographic and structural analysis, quantification of x-ray diffraction peak intensities confirmed that the alpha'/alpha '' mixtures contained as much as 46 vol % alpha '' (remaining alpha'). Vibrating sample magnetometry and SQUID magnetometry measurements of the alpha' and alpha'(54%)/alpha ''(46%) mixture, respectively, indicate enhanced magnetic moments for both the alpha' and alpha '' phases with respect to pure Fe. (C) 1996 American Institute of Physics. C1 IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. UNIV CALIF SANTA BARBARA,DEPT MAT,SANTA BARBARA,CA 93106. RP Brewer, MA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 16 TC 26 Z9 26 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5321 EP 5323 DI 10.1063/1.361365 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700316 ER PT J AU Kemner, KM Harris, VG Chakarian, V Idzerda, YU Elam, WT Kao, CC Feng, YC Laughlin, DE Woicik, JC AF Kemner, KM Harris, VG Chakarian, V Idzerda, YU Elam, WT Kao, CC Feng, YC Laughlin, DE Woicik, JC TI The role of Ta and Pt in segregation within Co-Cr-Ta and Co-Cr-Pt thin film magnetic recording media SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID RAY CIRCULAR-DICHROISM AB Polarization dependent extended x-ray absorption fine structure (PD-EXAFS) and magnetic circular dichroism (MCD) measurements of CoCrTa and CoCrPt films, sputter deposited at varying substrate temperatures, were performed to investigate the average local structure and chemistry about the Ta, Pt, and Co atoms and the average magnetic moment of the Co and Cr atoms within these films. Results from the MCD measurements indicate the average net magnetic moment of the Cr atoms is opposite in direction and five percent in amplitude relative to the Co moments. Inspection of the Fourier transforms of the XAFS data from these samples shows an increase in structural disorder around the Ta and Pt atoms with increasing substrate deposition temperature. A further comparison between the Ta and Pt edge EXAFS results show that the temperature-dependent increase in structural disorder is greater around the Ta atoms in the CoCrTa system than it is around the Pt atoms in the CoCrPt system. (C) 1996 American Institute of Physics. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. CARNEGIE MELLON UNIV,DEPT MAT SCI & ENGN,PITTSBURGH,PA 15213. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP Kemner, KM (reprint author), USN,RES LAB,WASHINGTON,DC 20375, USA. RI Harris, Vincent/A-8337-2009 NR 12 TC 7 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5345 EP 5347 DI 10.1063/1.361372 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700324 ER PT J AU FernandezBaca, JA Hill, P Chakoumakos, BC Ali, N AF FernandezBaca, JA Hill, P Chakoumakos, BC Ali, N TI Neutron diffraction study of the magnetic structures of CeMn2Ge2 and CeMn2Si2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB We have performed high-resolution neutron powder diffraction measurements on CeMn2Si2, and CeMn2Ge2 at temperatures between 12 and 550 K. Our measurements indicate that at high temperatures both compounds are paramagnetic. Below T-N=380 K CeMn2Si2 becomes a collinear AF, with a structure similar to that reported by Siek et al. in which the magnetic propagation vector is tau=(001). CeMn2Ge2, on the other hand, exhibits two different magnetic transitions. At T-N approximate to 415 K there is a transition to a collinear AF phase characterized by the commensurate propagation wave vector tau=(101). At T-C approximate to 318 K there is a transition to a conical structure with a ferromagnetic component along the c axis and a helical component in the ab plane. The helical component is characterized by a incommensurate propagation vector tau=(101-(qz)), where (qz) is temperatue dependent. (C) 1996 American Institute of Physics. C1 SO ILLINOIS UNIV,DEPT PHYS,CARBONDALE,IL 62901. RP FernandezBaca, JA (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. RI Fernandez-Baca, Jaime/C-3984-2014; Chakoumakos, Bryan/A-5601-2016 OI Fernandez-Baca, Jaime/0000-0001-9080-5096; Chakoumakos, Bryan/0000-0002-7870-6543 NR 11 TC 23 Z9 23 U1 0 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5398 EP 5400 DI 10.1063/1.362317 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700347 ER PT J AU Antropov, VP Harmon, BN AF Antropov, VP Harmon, BN TI Simultaneous molecular and spin dynamics: Quasiclassical approximation and quantum effects SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB We sketch the derivation of a set of equations of motion for the simultaneous treatment of both molecular and spin dynamics. The equations can be extended through the concept of imaginary time density functional theory, to describe the penetration of classically forbidden regions. (C) 1996 American Institute of Physics. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Antropov, VP (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 11 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5409 EP 5411 DI 10.1063/1.362321 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700351 ER PT J AU deMelo, CARS AF deMelo, CARS TI Magnetic exchange coupling mediated by bound states SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID RANGE AB Usually indirect exchange coupling is mediated by unbound, noncorrelated intermediate states (RKKY-like mechanisms) or by unbound, correlated intermediate states (superexchange-like mechanisms). Here we investigate the possibility of indirect magnetic exchange coupling mediated by bound, correlated intermediate states. As a concrete example we study the magnetic coupling between two magnetic impurities embedded in a semiconductor matrix. The importance of long ranged attractive Coulomb interactions between electrons and holes is emphasized. This attraction leads to exciton bound states which act as mediators of the effective exchange interaction between the two impurities. The resulting exchange interaction presents strong temperature dependence and can be analyzed in terms of the symmetry of the internal wavefunction of the exciton bound states. Possible applications of these results may include recent experimental results on ferromagnetic metal-semiconductor multilayers. (C) 1996 American Institute of Physics. RP deMelo, CARS (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5412 EP 5414 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700352 ER PT J AU Devine, MK Jiles, DC AF Devine, MK Jiles, DC TI The magnetomechanical effect in electrolytic iron SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB The effect of stress on the magnetization of high purity iron has been studied systematically at different locations on the M,H plane corresponding to a variety of magnetic states of the material. The results confirm earlier studies that show the sign of the derivative dM/sigma changes at different locations on the M,H plane, and can even change as a result of a monotonic increase of stress either in compression or tension. The observed behavior can be explained on the basis of a recent theory which predicts that the irreversible changes in magnetization resulting from changes in applied stress cause the magnetization to approach the anhysteretic magnetization curve at the given applied field strength. (C) 1996 American Institute of Physics. RP Devine, MK (reprint author), AMES LAB,AMES,IA 50011, USA. RI Jiles, David/H-9548-2012 NR 7 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5493 EP 5495 DI 10.1063/1.362287 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700386 ER PT J AU Gao, Z Jiles, DC Branagan, DJ McCallum, RW AF Gao, Z Jiles, DC Branagan, DJ McCallum, RW TI Dependence of energy dissipation on annealing temperature of melt-spun NdFeB permanent magnet materials SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID FE; ND AB A model of magnetic hysteresis which was developed originally for soft magnetic materials has been applied to melt-spun ribbons of Nd2Fe14B-based material. The crucial ideas in the model description of hysteresis center on a dissipation of energy due to hysteresis which is proportional to the change in magnetization. The Nd2Fe14B material was melt-spun amorphous and then annealed for a period of 24 h at temperatures ranging from 700 to 950 degrees C. This resulted in different grain sizes, depending on annealing temperature. Consequently the hysteresis curves represent the properties of the material as a function of both annealing temperature and grain size. It was found that the magnetic properties varied systematically with annealing temperature, and hence grain size, as would be expected. When modeling the magnetic properties it was found that the model parameters also varied systematically, in particular, the energy dissipation parameter k was to a first approximation a simple linear function of the annealing temperature and decreased with increasing annealing temperature as a result of grain growth. Therefore, this study revealed a basic relationship between materials processing conditions, microstructure, model parameters, and magnetic properties. (C) 1996 American Institute of Physics. RP Gao, Z (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Jiles, David/H-9548-2012 NR 6 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 5510 EP 5512 DI 10.1063/1.362294 PN 2A PG 3 WC Physics, Applied SC Physics GA UG877 UT WOS:A1996UG87700393 ER PT J AU Lewis, LH Welch, DO Pourarian, F AF Lewis, LH Welch, DO Pourarian, F TI Quantitative characterization of additional ferromagnetic phase in melt-quenched and sintered Nd-Fe-B-based magnets SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID PERMANENT-MAGNETS AB Quantitative evidence of a ferromagnetic Fe-rich minor phase present in both melt-quenched/die-upset and sintered magnets based on the Nd2Fe14B composition is presented. Full hysteresis loops were obtained at elevated temperatures (650 K less than or equal to T less than or equal to 800 K) and were subsequently decomposed to obtain the saturation magnetization M(s) of the minor phase as well as the paramagnetic slope of the 2-14-1 major phase as a function of temperature. Assuming a composition of pure iron, the calculated volume % of the impurity phase in the die-upset magnets is consistent with that obtained from previous observations of the widths and geometry of the intergranular phase found in the same magnets. The magnetization of the ferromagnetic impurity phase in the melt-quenched magnets decreases more rapidly than that of pure iron; extrapolation indicates a Curie temperature in the range 925 K4f quadrupolar transition, and the scattered photon was energy analyzed around the 3d-->2p fluorescent energy. Asymmetry ratios in the scattered intensity much larger than that of the L(III) XMCD effect (x-ray magnetic circular dichroism) were observed upon reversal of the magnetization of the sample or the helicity of the photon. A detailed comparison of these results with XMCD results from both the M(IV,V) edges and L(III) edge of Gd metal will be discussed. (C) 1996 American Institute of Physics. C1 EUROPEAN SYNCHROTRON RADIAT FACIL,F-38043 GRENOBLE,FRANCE. UNIV HELSINKI,DEPT PHYS,SF-00170 HELSINKI,FINLAND. RP Caliebe, WA (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973, USA. RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 14 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 6509 EP 6511 DI 10.1063/1.361927 PN 2B PG 3 WC Physics, Applied SC Physics GA UG878 UT WOS:A1996UG87800343 ER PT J AU Liu, GK Loong, CK Beitz, JV Cao, RX Chen, YH Suzuya, K AF Liu, GK Loong, CK Beitz, JV Cao, RX Chen, YH Suzuya, K TI Raman heterodyne detection of magnetic resonance in a phosphate glass SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc AB A Raman heterodyne detection of magnetic resonance has been performed for probing the local structure of a sodium phosphate glass doped with trivalent europium. High resolution rf modulation spectra between 0.5 and 10 MHz were observed without the laser field in resonance with electronic transitions of the glass. The intensity of the observed Raman heterodyne signal depends on the external static magnetic field and sample temperature as well as the intensity of the laser and rf fields. The ability of monitoring the rf resonance spectra with micrometer spatial resolution may offer a potentially important means to probe the variation of local structure in disordered solid state materials, (C) 1996 American Institute of Physics. RP Liu, GK (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 11 TC 0 Z9 0 U1 2 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 6512 EP 6514 DI 10.1063/1.361928 PN 2B PG 3 WC Physics, Applied SC Physics GA UG878 UT WOS:A1996UG87800344 ER PT J AU Butera, A Fainstein, A Tovar, M Fisk, Z Oseroff, SB AF Butera, A Fainstein, A Tovar, M Fisk, Z Oseroff, SB TI Gd concentration dependence of the spin reorientation critical field in Eu2-xGdxCuO4 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID MAGNETIC-PROPERTIES; GD2CUO4; R2CUO4; DC AB ESR measurements of the microwave absorption signal associated with weak ferromagnetism in single crystals of Eu(2-x)GD(x)CuO(4) are presented for X band (9.5 GHz) and L band (1.2 GHz) as a function of the Gd concentration. The strong absorption observed at low magnetic fields was interpreted, for samples with low Gd concentration, as due to a field-induced spin reorientation transition occurring at a critical field H-c, coincident with the in-plane magnetic anisotropy effective field H-eff(y). For larger x the Cu-Gd magnetic interaction needs to be considered leading to smaller H-c values. Our measurements show that for Gd concentrations in the range 0 less than or equal to x less than or equal to 1 the experimental data can be very well fitted with parameters derived from previous measurements. This fact indicates that these compounds have nearly the same in-plane anisotropy effective field, in spite of the small changes in lattice parameters. For x = 2 lattice distortions increase causing an H-c larger than the expected one. (C) 1996 American Institute of Physics. C1 COMIS NACL ENERGIA ATOM,INST BALSEIRO,RA-8400 SAN CARLOS BARILO,RIO NEGRO,ARGENTINA. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. SAN DIEGO STATE UNIV,DEPT PHYS,SAN DIEGO,CA 92182. RP Butera, A (reprint author), COMIS NACL ENERGIA ATOM,CTR ATOM BARILOCHE,RA-8400 SAN CARLOS BARILO,RIO NEGRO,ARGENTINA. NR 11 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 6577 EP 6579 DI 10.1063/1.361950 PN 2B PG 3 WC Physics, Applied SC Physics GA UG878 UT WOS:A1996UG87800369 ER PT J AU Khizroev, S Zuo, F Alexandrakis, GC Schlueter, JA Geiser, U Williams, JM AF Khizroev, S Zuo, F Alexandrakis, GC Schlueter, JA Geiser, U Williams, JM TI Vortex pinning in layered organic superconductors: kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 40th Annual Conference on Magnetism and Magnetic Materials CY NOV 06-09, 1995 CL PHILADELPHIA, PA SP Amer Inst Phys, IEEE, Magnet Soc, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN, Off Naval Res, Amer Ceram Soc ID TEMPERATURE; CRYSTALS; STATE; PHASE; CREEP AB Magnetization studies on organic single-crystal superconductors of k-(BEDT-TTF)(2)Cu[N(CN)(2)]Br with the field H parallel to the b axis (perpendicular to the conducting plane) show anomalous field and temperature dependence of vortex pinning in the mixed state. At high temperatures, the magnetization M decays with increasing field with a power-law dependence. The normalized relaxation rate S=d(ln M)/d(ln t) decreases monotonically with H. At low temperatures (T<7 K), a change of sign in the curvature of M(H) is observed, accompanied by a corresponding change in S as a function of H. Measurement of the irreversibility field H-rev shows a universal power-law dependence of H-rev on (1 - T/T-c) in the temperature range investigated. We suggest that the magnetic anomaly observed is due to a dimensional crossover in the nature of vortex pinning. (C) 1996 American Institute of Physics. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439. RP Khizroev, S (reprint author), UNIV MIAMI,DEPT PHYS,CORAL GABLES,FL 33124, USA. NR 15 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1996 VL 79 IS 8 BP 6586 EP 6588 DI 10.1063/1.362687 PN 2B PG 3 WC Physics, Applied SC Physics GA UG878 UT WOS:A1996UG87800372 ER PT J AU Pratt, ST AF Pratt, ST TI Interference effects in the two-photon ionization of nitric oxide SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOELECTRON ANGULAR-DISTRIBUTIONS; INDUCED CONTINUUM STRUCTURE; SIMULTANEOUS OMEGA-1,OMEGA-3 EXCITATION; COHERENT RADIATIVE CONTROL; QUANTUM DEFECT THEORY; LASER CONTROL; MAGNETIC-FIELD; VIBRATIONAL AUTOIONIZATION; 2-PHOTON INTERFERENCE; STATE DISTRIBUTIONS AB An experimental demonstration of the interference between two different resonant two-photon, two-color ionization processes from the A (2) Sigma(+), upsilon'=1 State of nitric oxide is presented. This interference effect does not require a well-defined phase relationship between the two ionizing lasers and should, in principle, allow the control of the overall ionization process by small detunings of either or both of the two resonant ionization pathways. This interference effect is quite general, and the potential of this scheme for the control of photoionization and photodissociation partial cross sections is discussed. (C) 1996 American Institute of Physics. RP Pratt, ST (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 47 TC 22 Z9 22 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1996 VL 104 IS 15 BP 5776 EP 5783 DI 10.1063/1.471309 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UE594 UT WOS:A1996UE59400007 ER PT J AU Woon, DE Dunning, TH Peterson, KA AF Woon, DE Dunning, TH Peterson, KA TI Ab initio investigation of the N-2-HF complex: Accurate structure and energetics SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; CORRELATED MOLECULAR CALCULATIONS; VIBRATIONAL ROTATIONAL ANALYSIS; HYDROGEN-FLUORIDE DIMER; WEAKLY-BOUND COMPLEXES; GAUSSIAN-BASIS SETS; WAVE-FUNCTIONS; BENCHMARK CALCULATIONS; INFRARED-SPECTROSCOPY; INTERMOLECULAR FORCES AB Augmented correlation consistent basis sets of double (aug-cc-pVDZ), triple (aug-cc-pVTZ), and modified quadruple zeta (aug-cc-pVQZ') quality have been employed to describe the N-2-HF potential energy surface at the Hartree-Fock level and with single reference correlated wave functions including Moller-Plesset perturbation theory (MP2, MP3, MP4) and coupled cluster methods [CCSD, CCSD(T)]. The most accurate computed equilibrium binding energies D-e are cm(-1) (with counterpoise correction) 810 cm(-1) (MP4/aug-cc-pVQZ') and 788 cm(-1) [CCSD(T)/aug-cc-pVQZ']. Estimated complete basis set limits of 814 cm(-1) (MP4) and 793 cm(-1) [CCSD(T)] indicate that the large basis set results are essentially converged. Harmonic frequencies and zero-point energies were determined through the aug-cc-pVTZ level. Combining the zero point energies computed at the aug-cc-pVTZ level with the equilibrium binding energies computed at the aug-cc-pVQZ' level, we predict D-0 values of 322 and 296 cm(-1), respectively, at the MP4 and CCSD(T) levels of theory. Using experimental anharmonic frequencies, on the other hand, the CCSD(T) value of D-0 is increased to 415 cm(-1), in good agreement with the experimental value recently reported by Miller and co-workers, 398+/-2 cm(-1). (C) 1996 American Institute of Physics. C1 PACIFIC NW LAB, THEORY MODELING & SIMULAT ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 60 TC 40 Z9 40 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 APR 15 PY 1996 VL 104 IS 15 BP 5883 EP 5891 DI 10.1063/1.471320 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UE594 UT WOS:A1996UE59400019 ER PT J AU Criss, RE Davisson, ML AF Criss, RE Davisson, ML TI Isotopic imaging of surface water/groundwater interactions, Sacramento valley, California SO JOURNAL OF HYDROLOGY LA English DT Article ID WATERS AB Groundwater isotope data across the Sacramento Valley, California establish two types of groundwater mining: (1) overdraft of ancient groundwater with limited recharge by surface waters, producing cones of depression; (2) ancient groundwater withdrawal followed by rapid recharge of irrigation water, reducing groundwater quality. The first type occurs in the Sacramento metropolitan area, where meteoric runoff is unnaturally high and 40 years of pumping have depressed water levels to 25 m below sea-level; inducing recharge from losing reaches of the Sacramento and American rivers. Lateral migration rates are quantified by the binary mixing between river water (delta(18)O = -10.8) and natural groundwater (delta(18)O = -7.0). The second type of mining occurs in agricultural regions to the west, where C-14 ages indicate that irrigation waters constitute more than 80% of modern recharge. This recharge has several characteristics of evaporated irrigation water, including: (1) high delta(18)O values (to > -6.0) that define closed contour patterns; (2) elevated NO3 concentrations (to 100 ppm); (3) low C-14 ages of less than 500 years. Stable isotope contours, augmented by C-14 data, provide dynamic recharge patterns in this profoundly disturbed, giant alluvial aquifer. On a large scale (> 100 km(2)), the lateral permeabilities of alluvial aquifers are essentially isotropic, whereas on a smaller scale (< 25 km(2)), anisotropy is evident and isotope values can be geographically complex and seasonally transient. Groundwater flow patterns implied by the isotope data can differ substantially from steady-state models based on head measurements. C1 LAWRENCE LIVERMORE NATL LAB,ISOTOPE SCI DIV L231,LIVERMORE,CA 94550. RP Criss, RE (reprint author), WASHINGTON UNIV,DEPT EARTH & PLANETARY SCI,ST LOUIS,MO 63130, USA. NR 32 TC 39 Z9 42 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD APR 15 PY 1996 VL 178 IS 1-4 BP 205 EP 222 DI 10.1016/0022-1694(96)83733-4 PG 18 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA UJ144 UT WOS:A1996UJ14400011 ER PT J AU Katsevich, AI AF Katsevich, AI TI Local reconstructions in exponential tomography SO JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS LA English DT Article ID RADON-TRANSFORM AB In this paper, pseudolocal and local approaches to the tomographic reconstruction of discontinuities of an unknown function f from its exponential Radon transform data g(theta, p) are developed. A function f is supposed to be piecewise-continuous and compactly supported. A pseudolocal tomography function f(d)(X) is introduced and it is proved that the difference f-f(d) is continuous. Therefore, locations and values of jumps of f can be recovered from f(d), the computation of which is pseudolocal: for the reconstruction of f(d) at a point x one needs to know g(theta, p) only for (theta, p) satisfying \Theta . x - p\ less than or equal to d. Investigation of the properties of f(d) as d --> 0 is given. Also a local exponential tomography function f(Lambda)((mu)) is proposed and it is proved that f(Lambda)((mu)) is the result of action on f of an elliptic pseudo-differential operator with the principal symbol \xi\. Thus sing supp(f(Lambda)((mu))) = sing supp(f) and, moreover, the asymptotics of f(Lambda)((mu))(x) as x --> S, the discontinuity curve of f, are established. These asymptotics allow one to find values of jumps of f across S using local exponential tomography. (C) 1996 Academic Press, Inc. RP Katsevich, AI (reprint author), LOS ALAMOS NATL LAB,CIC-3,MS K-990,LOS ALAMOS,NM 87545, USA. NR 19 TC 2 Z9 2 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-247X J9 J MATH ANAL APPL JI J. Math. Anal. Appl. PD APR 15 PY 1996 VL 199 IS 2 BP 425 EP 444 DI 10.1006/jmaa.1996.0151 PG 20 WC Mathematics, Applied; Mathematics SC Mathematics GA UF930 UT WOS:A1996UF93000008 ER PT J AU Mi, J Figliola, RS Anderson, IE AF Mi, J Figliola, RS Anderson, IE TI A numerical simulation of gas flow field effects on high pressure gas atomization due to operating pressure variation SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE gas atomization; numerical simulation ID JETS AB High pressure gas atomization is emerging as an efficient method of producing high yields of ultrafine metal and alloy powders. The results of a numerical study of the gas-only flow field of a high pressure, confined feed, annular jet gas-metal atomizer are compared with experimental data and are reported in this paper. The axisymmetric, turbulent, compressible Navier-Stokes equations are solved for the gas-only flow in the vicinity of the melt tip. A parametric variation of gas atomizing pressure and its effect on gas flow field is examined. The numerical results demonstrate the existence of a strong recirculation region, mixing layer, and shock structures downstream of the melt tip in good agreement with experimental observations and past studies. The paper focuses on the characterization of the flow field, including a comparison of numerical and experimental data and how the results support a droplet formation mechanism over a range of atomizing pressures. C1 AMES LAB,DIV MET & CERAM,AMES,IA 50011. RP Mi, J (reprint author), CLEMSON UNIV,DEPT MECH ENGN,CLEMSON,SC 29634, USA. NR 25 TC 15 Z9 19 U1 2 U2 6 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 15 PY 1996 VL 208 IS 1 BP 20 EP 29 DI 10.1016/0921-5093(95)10046-6 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA UM130 UT WOS:A1996UM13000003 ER PT J AU Nieh, TG Schwartz, AJ Wadsworth, J AF Nieh, TG Schwartz, AJ Wadsworth, J TI Superplasticity in a 17 vol% SIC particulate-reinforced ZK60A magnesium composite (ZK60/SiC/17p) SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE superplasticity; magnesium composites; magnesium alloys ID TEMPERATURE; DIFFUSION AB The superplastic characteristics of a 17 vol.% SiC particulate-reinforced ZK60A magnesium composite (ZK60/SiC/17p) have been studied. The composite has a fine microstructure (grain size similar to 0.5 mu m) and is stable at high temperatures. As a result of the fine microstructure, the composite exhibits superplasticity (with an elongation to failure of 350%) at very high strain rate (similar to 1 s(-1)). The superplastic properties of the composite, including elongation, strain rate sensitivity, activation energy, grain size dependence, and cavitation, were all characterized. From experimental results, i.e., the strain rate sensitivity value, the grain size dependence of strain rate, and the activation energy, the operative superplastic deformation mechanism in ZK60/SiC/17p is proposed. A comparison between the superplastic behavior of the composite and that of magnesium alloys, and particularly the unreinforced magnesium alloy counterpart of the composite, has also been made. RP Nieh, TG (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-350,LIVERMORE,CA 94550, USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 24 TC 61 Z9 65 U1 1 U2 10 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD APR 15 PY 1996 VL 208 IS 1 BP 30 EP 36 DI 10.1016/0921-5093(95)10060-1 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA UM130 UT WOS:A1996UM13000004 ER PT J AU Cayon, L MartinezGonzalez, E Sanz, JL Sugiyama, N Torres, S AF Cayon, L MartinezGonzalez, E Sanz, JL Sugiyama, N Torres, S TI Omega from the COBE-DMR anisotropy maps SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods, data analysis; cosmic microwave background; cosmology, observations ID COSMIC VARIANCE; RADIATION; PERTURBATIONS; UNIVERSES AB We have made a likelihood statistical analysis of the angular correlations in the COBE-DMR two-year sky maps by Monte Carlo simulation of the temperature fluctuations. We assume an open universe and consider the primordial power spectrum of Harrison-Zeldovich, P(k) = Ak. We find that the flatness of the universe is not implied by the data. The quadrupole normalization amplitude, Q(rms-PS), is related to the density parameter, Omega, by Omega(rms-PS) = 10.67 + 55.81 Omega - 2128.59 Omega(2) + + 81.26 Omega(3) mu K. We have determined the probability distribution function (pdf) of Omega arising from cosmic plus sampling (i.e. 20 degrees galactic cut) variance which generically shows a bimodal shape. The uncertainty as given by the rms is approximate to 0.35; therefore, to constrain Omega better, experiments sensitive to higher multipoles (l > 20) should be considered. C1 CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. UNIV CANTABRIA,CONSEJO SUPER INVEST CIENT,INST FIS,E-39005 SANTANDER,SPAIN. UNIV TOKYO,FAC SCI,DEPT PHYS,TOKYO 113,JAPAN. OBSERV ASTRON UNIV NACL,BOGOTA,COLOMBIA. CTR INT FIS,BOGOTA,COLOMBIA. RP Cayon, L (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Martinez-Gonzalez, Enrique/E-9534-2015 OI Martinez-Gonzalez, Enrique/0000-0002-0179-8590 NR 33 TC 7 Z9 7 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 15 PY 1996 VL 279 IS 4 BP 1095 EP 1100 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UG553 UT WOS:A1996UG55300008 ER PT J AU Dimopoulos, S Thomas, S AF Dimopoulos, S Thomas, S TI Dynamical relaxation of the supersymmetric CP violating phases SO NUCLEAR PHYSICS B LA English DT Article ID ELECTRIC-DIPOLE MOMENT; THALLIUM FLUORIDE; STRING THEORY; T-VIOLATION; NEUTRON; SUPERGRAVITY; SYMMETRY; PHYSICS; SEARCH; MODELS AB A supersymmetric generalization of the Peccei-Quinn mechanism is proposed in which two U(1) CP violating phases of the supersymmetric standard model are promoted to dynamical variables. This amounts to postulating the existence of spontaneously broken global symmetries in the supersymmetry breaking sector. The vacuum can then relax near a CP conserving point. As a consequence the strong CP and supersymmetric CP problems may be solved by similar mechanisms. C1 STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP Dimopoulos, S (reprint author), CERN,DIV THEORET PHYS,CH-1211 GENEVA 23,SWITZERLAND. NR 58 TC 106 Z9 106 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 15 PY 1996 VL 465 IS 1-2 BP 23 EP 33 DI 10.1016/0550-3213(96)00065-X PG 11 WC Physics, Particles & Fields SC Physics GA UK755 UT WOS:A1996UK75500002 ER PT J AU Fagan, PA Spielmann, HP Sigurdsson, ST Rink, SM Hopkins, PB Wemmer, DE AF Fagan, PA Spielmann, HP Sigurdsson, ST Rink, SM Hopkins, PB Wemmer, DE TI An NMR study of [d(CGCGAATTCGCG)](2) containing an interstrand cross-link derived from a distamycin-pyrrole conjugate SO NUCLEIC ACIDS RESEARCH LA English DT Article ID SEQUENCE-SPECIFIC CLEAVAGE; MINOR GROOVE; MITOMYCIN-C; DNA-BINDING; N-BROMOACETYLDISTAMYCIN; COMPLEX; NETROPSIN; RECOGNITION; OLIGOPEPTIDES; CYTOTOXICITY AB Minor groove binding compounds related to distamycin A bind DNA with high sequence selectivity, recognizing sites which contain various combinations of A . T and G . C base pairs, These molecules have the potential to deliver cross-linking agents to the minor groove of a target DNA sequence, We have studied the covalent DNA-DNA cross-linked complex of 2,3-bis(hydroxymethyl)pyrrole-distamycin and [d(CGCGAATTCGCG)](2). The alkylating pyrrole design is based on the pharmacophore of mitomycin C and is similar in substructure to another important class of natural products, the oxidatively activated pyrrolizidine alkaloids, Ligand-DNA NOEs confirm that the tri(pyrrole-carboxamide) unit of the ligand is bound in the minor groove of the central A+T tract, Unexpectedly, it is shifted by 1 bp with respect to the distamycin A binding site on this DNA sequence, The cross-link bridges the 2-amino position of two guanine residues, G(4) and G(22). The C-3 . G(22) and G(4) . C-21 base pairs exhibit Watson-Crick base pairing, with some local distortion, as evidenced by unusual intensities observed for DNA-DNA NOE cross-peaks, The model is compared with a related structure of a cross-linked mitomycin C:DNA complex. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DEPT BIOL STRUCT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV WASHINGTON,DEPT CHEM,SEATTLE,WA 98195. RI Sigurdsson, Snorri/B-9359-2008 OI Sigurdsson, Snorri/0000-0003-2492-1456 FU NIGMS NIH HHS [GM-14966, GM-43219, GM-45804] NR 44 TC 18 Z9 18 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 APR 15 PY 1996 VL 24 IS 8 BP 1566 EP 1573 DI 10.1093/nar/24.8.1566 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UH370 UT WOS:A1996UH37000025 PM 8628693 ER PT J AU Sullivan, A Bonlie, J Price, DF White, WE AF Sullivan, A Bonlie, J Price, DF White, WE TI 1.1-J, 120-fs laser system based on Nd:glass-pumped Ti:sapphire SO OPTICS LETTERS LA English DT Article ID PULSES AB We have developed an ultrashort-pulse laser system in which the final Ti:sapphire amplifier stage is pumped by the frequency-doubled output of a Nd:glass laser. The laser produces pulses with an energy in excess of 1 J on target and an estimated peak focused irradiance of 5 x 10(19) W/cm(2). (C) 1996 Optical Society of America. RP Sullivan, A (reprint author), LAWRENCE LIVERMORE NATL LAB,7000 E AVE,L-251,LIVERMORE,CA 94550, USA. NR 10 TC 39 Z9 39 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 15 PY 1996 VL 21 IS 8 BP 603 EP 605 DI 10.1364/OL.21.000603 PG 3 WC Optics SC Optics GA UE617 UT WOS:A1996UE61700019 PM 19876097 ER PT J AU Bayly, BJ Holm, DD Lifschitz, A AF Bayly, BJ Holm, DD Lifschitz, A TI Three-dimensional stability of elliptical vortex columns in external strain flows SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article ID 3-DIMENSIONAL INSTABILITY; INCOMPRESSIBLE FLUID; STRATIFIED FLUID; IMPOSED STRAIN; VORTICES; SHEAR; DYNAMICS; FILAMENT; FIELD AB The Kirchhoff-Kida family of elliptical vortex columns in flows with uniform strain and rotation displays a rich variety of dynamical behaviours, even in a purely two-dimensional setting. In this paper, we address the stability of these columns with respect to three-dimensional perturbations via the geometrical optics method. In the case when the external strain is equal to zero, the analysis reduces to the stability of a steady elliptical vortex in a rotating frame. When the external strain is non-zero, the stability analysis reduces to the theory of a Schrodinger equation with quasi-periodic potential. We present stability results for a variety of different Kirchhoff-Kida flows. The vortex columns are typically unstable except when the interior vorticity is approximately the negative of the background vorticity, so that the flow in the inertial frame is nearly a potential flow. C1 LOS ALAMOS NATL LAB, CTR NONLINEAR STUDIES, LOS ALAMOS, NM 87545 USA. LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. UNIV ILLINOIS, DEPT MATH, CHICAGO, IL 60607 USA. RP Bayly, BJ (reprint author), UNIV ARIZONA, DEPT MATH, TUCSON, AZ 85721 USA. OI Holm, Darryl D/0000-0001-6362-9912 NR 58 TC 44 Z9 44 U1 0 U2 1 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD APR 15 PY 1996 VL 354 IS 1709 BP 895 EP 926 DI 10.1098/rsta.1996.0036 PG 32 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UH371 UT WOS:A1996UH37100003 ER PT J AU Wang, LW Zunger, A AF Wang, LW Zunger, A TI Pseudopotential calculations of nanoscale CdSe quantum dots SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION; BAND AB A plane-wave semiempirical pseudopotential method with nonlocal potentials and spin-orbit coupling is used to calculate the electronic structure of surface-passivated wurtzite CdSe quantum dots with up to 1000 atoms. The calculated optical absorption spectrum reproduces the features of the experimental results and the exciton energies agree to within similar to 0.1 eV over a range of dot sizes. The correct form of Coulomb interaction energy with size-dependent dielectric constant is found to be essential for such good agreement. C1 NATL RENEWABLE ENERGY LAB, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 25 TC 350 Z9 355 U1 3 U2 37 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 APR 15 PY 1996 VL 53 IS 15 BP 9579 EP 9582 DI 10.1103/PhysRevB.53.9579 PG 4 WC Physics, Condensed Matter SC Physics GA UJ296 UT WOS:A1996UJ29600023 ER PT J AU Yi, SN Chen, XM Quinn, JJ AF Yi, SN Chen, XM Quinn, JJ TI Composite-fermion excitations and the electronic spectra of fractional quantum Hall systems SO PHYSICAL REVIEW B LA English DT Article ID FILLED LANDAU-LEVEL; HIERARCHY; STATES; FLUID; GAS AB In the composite-fernion (CF) mean-field theory of a two-dimensional electron system, an electron Landau level whose filling factor is an odd denominator fraction can be transformed into an integral number of filled CF Landau levels. This CF state corresponds to the ground state of a Laughlin incompressible liquid, with an energy gap equal to the ''effective'' CF cyclotron energy. Excited states are described by n(QE) and n(QH), the number of quasielectron and quasihole CF excitations. The energies of individual quasielectrons or quasiholes and their ''Fermi liquid'' interactions can be investigated by comparing the CF picture with exact numerical results for a small number of electrons on a spherical surface. C1 KOREA MARITIME UNIV,PUSAN 606791,SOUTH KOREA. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Yi, SN (reprint author), UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996, USA. NR 20 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 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 15 BP 9599 EP 9601 DI 10.1103/PhysRevB.53.9599 PG 3 WC Physics, Condensed Matter SC Physics GA UJ296 UT WOS:A1996UJ29600028 ER PT J AU Smith, AP Benedek, R Trouw, FR Minkoff, M Yang, LH AF Smith, AP Benedek, R Trouw, FR Minkoff, M Yang, LH TI Quasi-two-dimensional quantum states of H-2 in stage-2 Rb-intercalated graphite SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; HYDROGEN; ENERGY; POTENTIALS; TRANSITION; DYNAMICS; SURFACES; PHASES; METALS AB Inelastic-incoherent-neutron scattering can be a valuable nanostructural probe of H-2-doped porous materials, provided the spectral peaks can be interpreted in terms of crystal-field-split hydrogen-molecule energy levels, which represent a signature of the local symmetry. Inelastic-neutron-scattering measurements as well as extensive theoretical analyses have been performed on stage-2 Rb-intercalated graphite (Rb-GIC), with phys isorbed H-2, HD, and D-2 [composition C(24)M(H-2)(x), with x = 0.8 or 1.0], a layered porous system with abundant spectral peaks, to assess whether the crystal-field-state picture enables a quantitative understanding of the observed structure. The experiments were made at 15 K on the QENS spectrometer at the intense pulsed neutron source. Potential-energy surfaces for molecular rotational and translational motion (parallel and perpendicular to the intercalant plane), as well as the intermolecular interactions of hydrogen molecules in Rb-GIC, were calculated within local-density-functional theory (LDFT). A root 7 x root 7 periodic unit cell (with composition C28Rb) was treated in the calculations. Model potentials, parametrized using results of the LDFT calculations, were employed in schematic calculations of rotational and translational excited state spectra of a single physisorbed H-2 molecule in Rb-GIC. Results of our analysis are basically consistent with the assignment by Stead et al. of the lowest-lying peak at 1.4 meV to a rotational-tunneling transition of an isotropic hindered-rotor oriented normal to the planes, but indicate a small azimuthal anisotropy and a lower barrier than for the isotropic case. A peak of low intensity at 4.0 meV is most likely a host feature, Based on the experimental isotope shifts and the theoretically predicted states, we conclude that spectral peaks at 11 and 22 meV are most likely related to center of mass excitations. We attribute the relatively weak peak at 32 meV to a librational excitation, and that at 44 meV to an out-of-plane vibration. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV INTENSE PULSED NEUTRON SOURCE,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. LAWRENCE LIVERMORE NATL LAB,DIV PHYS H,LIVERMORE,CA 94551. NR 45 TC 12 Z9 12 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 APR 15 PY 1996 VL 53 IS 15 BP 10187 EP 10199 DI 10.1103/PhysRevB.53.10187 PG 13 WC Physics, Condensed Matter SC Physics GA UJ296 UT WOS:A1996UJ29600105 ER PT J AU Shirley, EL Terminello, LJ Klepeis, JE Himpsel, FJ AF Shirley, EL Terminello, LJ Klepeis, JE Himpsel, FJ TI Detailed theoretical photoelectron angular distributions for LiF(100) SO PHYSICAL REVIEW B LA English DT Article ID NORM-CONSERVING PSEUDOPOTENTIALS; CORE POLARIZATION POTENTIALS; GROUND-STATE; ABINITIO CALCULATIONS; VALENCE CORRELATION; LITHIUM-FLUORIDE; BRILLOUIN-ZONE; SPECIAL POINTS; BAND-GAPS; ELECTRON AB We model photoelectron angular distributions obtained earlier by Himpsel et al, [Phys. Rev, Lett. 68, 3611 (1992)] for the F 2p bands in LiF(100). The F 2p states are treated within a many-body, quasiparticle approach, and a nearly-free-electron model is presented for the description of conduction-band states relevant to the photoemission process. In the quasiparticle results, we find a band gap of 14.4 eV and a F 2p bandwidth of 3.6 eV, in satisfactory agreement with experimental values of 14.2 and 3.5 eV for these respective quantities. A method for computing photoelectron angular distributions is presented, followed by a comparison of simulated and measured photoelectron angular distributions for several parts of the three-dimensional Brillouin zone. In this comparison, constant-energy contours in the F 2p bands are clearly portrayed in both theoretical and experimental images. Using the model, we also identify the origin of a Brillouin-zone-dependent intensity variation for equivalent valence states, i.e., states which are related by reflection through a (010)-type Bragg plane and which lie close to such a plane. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. IBM CORP, THOMAS J WATSON RES CTR, YORKTOWN HTS, NY 10598 USA. RP Shirley, EL (reprint author), NIST, PHYS LAB, RADIOMETR PHYS DIV, GAITHERSBURG, MD 20899 USA. NR 70 TC 47 Z9 48 U1 3 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 15 BP 10296 EP 10309 DI 10.1103/PhysRevB.53.10296 PG 14 WC Physics, Condensed Matter SC Physics GA UJ296 UT WOS:A1996UJ29600117 ER PT J AU Wei, SH Zunger, A AF Wei, SH Zunger, A TI Chemical trends in band offsets of Zn- and Mn-based II-VI superlattices: d-level pinning and offset compression SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM-WELLS; SEMICONDUCTORS; HETEROJUNCTIONS; DENSITY; CONFINEMENT; STATES AB Calculation of the unstrained band offsets between conventional zinc-blende II-VI superlattices (ZnS/ZnSe/ZnTe), or between magnetic II-VI superlattices (MnS/MnSe/MnTe) or combinations thereof (MnX/ZnX) show that (i) the range of offsets spanned by different magnetic II-VI superlattices is compressed by a factor of 2 relative to the range of offsets spanned by conventional II-VI superlattices, (ii) the distance between the Mn d band and the valence-band maximum in MnX depends weakly on X, while in conventional II-VI superlattices (e.g., Zn 3d in ZnX) there is a wider spread, and (iii) unlike the case for conventional common-anion II-VI superlattices, the mixed offset Delta E(V)(ZnX/MnX) depends strongly on X. We show that all three effects have a simple and common physical origin. RP Wei, SH (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013 NR 30 TC 26 Z9 27 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 16 BP 10457 EP 10460 DI 10.1103/PhysRevB.53.R10457 PG 4 WC Physics, Condensed Matter SC Physics GA UJ485 UT WOS:A1996UJ48500006 ER PT J AU Starke, K Kaduwela, AP Liu, Y Johnson, PD VanHove, MA Fadley, CS Chakarian, V Chaban, EE Meigs, G Chen, CT AF Starke, K Kaduwela, AP Liu, Y Johnson, PD VanHove, MA Fadley, CS Chakarian, V Chaban, EE Meigs, G Chen, CT TI Spin-polarized photoelectrons excited by circularly polarized radiation from a nonmagnetic solid SO PHYSICAL REVIEW B LA English DT Article ID RESOLVED PHOTOEMISSION; SYNCHROTRON RADIATION; PHOTO-ELECTRONS; XENON ATOMS; MONOCHROMATORS; DIFFRACTION AB We report a spin analysis of core-level photoelectrons excited by circularly polarized x rays from a nonmagnetic solid. In a combined experimental and theoretical study, we show that the spin-orbit-split W 4f(7/2) and 4f(5/2) photoemission lines from W(110) exhibit high spin polarizations of opposite sign that vary with energy and emission direction. These results suggest the study of the magnetic structure of nonmagnetic/ferromagnetic interfaces formed on high-atomic-number substrates by spin-polarized photoelectron diffraction. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. USN,RES LAB,WASHINGTON,DC 20375. RP Starke, K (reprint author), AT&T BELL LABS,600 MT AVE,MURRAY HILL,NJ 07974, USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 33 TC 20 Z9 20 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 16 BP 10544 EP 10547 PG 4 WC Physics, Condensed Matter SC Physics GA UJ485 UT WOS:A1996UJ48500028 ER PT J AU Althoff, JD Johnson, DD Pinski, FJ Staunton, JB AF Althoff, JD Johnson, DD Pinski, FJ Staunton, JB TI Electronic origins of ordering in multicomponent metallic alloys: Application to the Cu-Ni-Zn system SO PHYSICAL REVIEW B LA English DT Article ID RANDOM SUBSTITUTIONAL ALLOYS; SOLID-SOLUTIONS; SCATTERING AB We investigate the ordering tendencies of the fee Cu-Ni-Zn system using a recently developed first-principles, density-functional-based theory of atomic short-range order (ASRO) in disordered substitutional alloys of an arbitrary number of components. We find for the binary alloys a variety of effects which should lead to competition in the ternaries: commensurate ordering (Ni-Zn), long-period ordering (Cu-rich Cu-Zn), and clustering (Cu-Ni), in agreement with experiment. We calculate the ASRO of various disordered ternary alloys (as described by the Warren-Cowley pair-correlation function) and discuss its relationship to the electronic structure of the binary and ternary disordered alloys. We find [100]-type ASRO over an extensive composition range for the ternary alloys, even though all of the ordering tendencies for binaries and ternaries have a Fermi-surface-driven component. We discuss how alloying and disorder broadening lead to these ASRO properties. For Cu50Ni25Zn25, the agreement for our calculated ASRO and its indication of two ordered states at low temperature are in good agreement with experiments. C1 UNIV CINCINNATI, DEPT PHYS, CINCINNATI, OH 45221 USA. UNIV WARWICK, DEPT PHYS, COVENTRY CV7 4AL, W MIDLANDS, ENGLAND. RP Althoff, JD (reprint author), SANDIA NATL LABS, COMPUTAT MAT SCI DEPT, MS 9161, LIVERMORE, CA 94551 USA. OI Johnson, Duane/0000-0003-0794-7283 NR 44 TC 20 Z9 20 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 16 BP 10610 EP 10625 DI 10.1103/PhysRevB.53.10610 PG 16 WC Physics, Condensed Matter SC Physics GA UJ485 UT WOS:A1996UJ48500036 ER PT J AU Springborg, M Albers, RC AF Springborg, M Albers, RC TI Electronic structure of Pt in polyyne SO PHYSICAL REVIEW B LA English DT Article ID HELICAL POLYMERS AB We present results of first-principles calculations on [Pt(PH3)(2)C-6](x), which is a linear-chain compound consisting of alternating Pt atoms (which have PH3 sidegroups) with a linear group of six C atoms. The calculations have been performed with the density-functional linear muffin-tin orbital method for a single, infinite, periodic chain. We discuss, in particular, the orbitals near the Fermi energy; we also use a semiquantitative approach to estimate the effects of spin-orbit coupling. Finally, we examine the perturbation on the band structure that are induced by polaronic defects and suggest that these may be relevant for interpreting the experimental results on this and related polymers. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Springborg, M (reprint author), UNIV KONSTANZ,DEPT CHEM,D-78434 CONSTANCE,GERMANY. NR 17 TC 16 Z9 16 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 16 BP 10626 EP 10631 DI 10.1103/PhysRevB.53.10626 PG 6 WC Physics, Condensed Matter SC Physics GA UJ485 UT WOS:A1996UJ48500037 ER PT J AU Kim, SK Koo, YM Chernov, VA Padmore, H AF Kim, SK Koo, YM Chernov, VA Padmore, H TI Clear evidence for strain changes according to Co layer thickness in metastable Co/Pd(111) multilayers: An extended x-ray absorption fine structure study SO PHYSICAL REVIEW B LA English DT Article ID PERPENDICULAR MAGNETIC-ANISOTROPY; SUPERLATTICES; FILMS; CO/PT; SPECTROSCOPY; DIFFRACTION AB We have measured fluorescence-yield extended x-ray absorption fine structure (EXAFS) on a series of (Co x Angstrom+Pd 11 Angstrom)(13) metallic multilayers. To examine the local atomic structure around Co and its anisotropy, Co K-edge EXAFS measurements were performed at near-grazing incidence of synchrotron radiation incorporating linear polarization dependence. We generally observed, with decreasing Co layer thickness, increasing, in-plane interatomic distance and decreasing, out-of-plane interatomic distance in Co atoms. For a (Co 10 Angstrom +Pd 11 Angstrom)(13) multilayer, strain values of in-plane and out-of-plane Co atoms are estimated to be 3.6+/-0.5% in tensile and 3.0+/-0.4% in compressive strain. C1 BUDKER NUCL PHYS INST,INST CATALYSIS,NOVOSIBIRSK 630090,RUSSIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Kim, SK (reprint author), POHANG UNIV SCI & TECHNOL,POHANG 790784,SOUTH KOREA. RI Kim, Sang-Koog/J-4638-2014 NR 41 TC 24 Z9 24 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1996 VL 53 IS 16 BP 11114 EP 11119 DI 10.1103/PhysRevB.53.11114 PG 6 WC Physics, Condensed Matter SC Physics GA UJ485 UT WOS:A1996UJ48500095 ER PT J AU Gates, EI Gyuk, G Turner, MS AF Gates, EI Gyuk, G Turner, MS TI Gravitational microlensing and the galactic halo SO PHYSICAL REVIEW D LA English DT Article ID COLD DARK MATTER; MILKY-WAY; ROTATION CURVE; MASS DENSITY; GALAXY; MODEL; UNIVERSE; OBJECTS; BULGE AB By means of extensive galactic modeling we study the implications of the MACHO, EROS, and OGLE microlensing results for the composition of the dark halo of the Galaxy as well as for other properties of the Galaxy. While microlensing toward the LMC most directly probes the halo MACHO mass fraction, microlensing toward the bulge is almost equally important as it strongly constrains the Galactic model. We take the Galaxy to be comprised of luminous and dark disk components, a bulge, and a dark halo consisting of both MACHO's and cold dark matter with each component being described by several observationally motivated parameters. We pare down an initial model space of millions of galactic models to viable models, those which are consistent with the observational data; including rotation curve, local projected mass density, and microlensing rates toward the LMC and bulge. On the basis of a conservative, minimal set of observational constraints an all-MACHO halo cannot yet be excluded, although in most viable models of the Galaxy the halo MACHO fraction is between 0% and 30%, consistent with expectations for a universe whose primary component is cold dark matter. An all-MACHO halo is required to be light, and when data on the local escape velocity and satellite-galaxy proper motions, which probe the extent of the dark halo, are taken into account, models which have a high MACHO mass fraction are ruled out. We also explore the possibility that there are no MACHO's in the halo. Finally, we point out several important tests that could definitively exclude an all-MACHO halo, e.g., evidence that the optical depth for microlensing is less than 1.5 X 10(-7) toward the LMC or greater than 3 X 10(-6) toward the bulge. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. RP Gates, EI (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 73 TC 55 Z9 55 U1 2 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 APR 15 PY 1996 VL 53 IS 8 BP 4138 EP 4176 DI 10.1103/PhysRevD.53.4138 PG 39 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UH722 UT WOS:A1996UH72200004 ER PT J AU Abe, F Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Apollinari, G Areti, H Atac, M Auchincloss, P Azfar, F Azzi, P Bacchetta, N Badgett, W Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Bartalini, P Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Bertolucci, S Bhatti, A Biery, K Binkley, M Bird, F Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bortoletto, D Boswell, C Boulos, T Brandenburg, G Bromberg, C BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cen, Y Cervelli, F Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D Cunningham, JD Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demortier, L Denby, B Deninno, M Derwent, PF Devlin, T Dickson, M Dittmann, JR Donati, S Drucker, RB Dunn, A Einsweiler, K Elias, JE Ely, R Engels, E Eno, S Errede, D Errede, S Fan, Q Farhat, B Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fry, A Fuess, TA Fukui, Y Funaki, S Gagliardi, G Galeotti, S Gallinaro, M Garfinkel, AF Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Goulianos, K Grassmann, H Grewal, A Groer, L GrossoPilcher, C Haber, C Hahn, SR Hamilton, R Handler, R Hans, RM Hara, K Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Heinrich, J CroninHennessy, D Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Hurst, P Huston, J Huth, J Hylen, J Incagli, M Incandela, J Iso, H Jensen, H Jessop, CP Joshi, U Kadel, RW Kajfasz, E Kamon, T Kaneko, T Kardelis, DA Kasha, H Kato, Y Keeble, L Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuhlmann, SE Kuns, E Laasanen, AT Labanca, N Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Loomis, C Long, O Loreti, M Low, EH Lu, J Lucchesi, D Luchini, CB Lukens, P Lys, J Maas, P Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Michail, G Mikamo, S Miller, M Miller, R Mimashi, T Miscetti, S Mishina, M Mitsushio, H Miyashita, S Morita, Y Moulding, S Mueller, J Mukherjee, A Muller, T Musgrave, P Nakae, LF Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Nodulman, L Ogawa, S Oh, SH Oh, KE Oishi, R Okusawa, T Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Park, S Patrick, J Pauletta, G Paulini, M Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Plunkett, R Pondrom, L Produit, N Proudfoot, J Ptohos, F Punzi, G Ragan, K Rimondi, F Ristori, L RoachBellino, M Robertson, WJ Rodrigo, T Romano, J Rosenson, L Sakumoto, WK Saltzberg, D Sansoni, A Scarpine, V Schindler, A Schlabach, P Schmidt, EE Schmidt, MP Schneider, O Sciacca, GF Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Sgolacchia, A Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Smith, DA Snider, FD Song, L Song, T Spalding, J Spiegel, L Sphicas, P Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Stuart, D Sullivan, G Sumorok, K Swartz, RL Takahashi, T Takikawa, K Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, J Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Tollefson, K Tollestrup, A Tonnison, J deTroconiz, JF Tseng, J Turcotte, M Turini, N Uemura, N Ukegawa, F Unal, G vandenBrink, SC Vejcik, S Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wainer, N Walker, RC Wang, C Wang, CH Wang, G Wang, J Wano, MJ Wang, QF Warburton, A Watts, G Watts, T Webb, R Wei, C Wendt, W Wenzel, H Wester, WC Westhusing, T Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Wolinski, J Wu, DY Wu, X Wyss, J Yagil, A Yao, L Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, S Zhang, W Zucchelli, S AF Abe, F Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Apollinari, G Areti, H Atac, M Auchincloss, P Azfar, F Azzi, P Bacchetta, N Badgett, W Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Bartalini, P Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Bertolucci, S Bhatti, A Biery, K Binkley, M Bird, F Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bortoletto, D Boswell, C Boulos, T Brandenburg, G Bromberg, C BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cen, Y Cervelli, F Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D Cunningham, JD Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demortier, L Denby, B Deninno, M Derwent, PF Devlin, T Dickson, M Dittmann, JR Donati, S Drucker, RB Dunn, A Einsweiler, K Elias, JE Ely, R Engels, E Eno, S Errede, D Errede, S Fan, Q Farhat, B Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fry, A Fuess, TA Fukui, Y Funaki, S Gagliardi, G Galeotti, S Gallinaro, M Garfinkel, AF Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Goulianos, K Grassmann, H Grewal, A Groer, L GrossoPilcher, C Haber, C Hahn, SR Hamilton, R Handler, R Hans, RM Hara, K Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Heinrich, J CroninHennessy, D Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Hurst, P Huston, J Huth, J Hylen, J Incagli, M Incandela, J Iso, H Jensen, H Jessop, CP Joshi, U Kadel, RW Kajfasz, E Kamon, T Kaneko, T Kardelis, DA Kasha, H Kato, Y Keeble, L Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuhlmann, SE Kuns, E Laasanen, AT Labanca, N Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Loomis, C Long, O Loreti, M Low, EH Lu, J Lucchesi, D Luchini, CB Lukens, P Lys, J Maas, P Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Michail, G Mikamo, S Miller, M Miller, R Mimashi, T Miscetti, S Mishina, M Mitsushio, H Miyashita, S Morita, Y Moulding, S Mueller, J Mukherjee, A Muller, T Musgrave, P Nakae, LF Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Nodulman, L Ogawa, S Oh, SH Oh, KE Oishi, R Okusawa, T Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Park, S Patrick, J Pauletta, G Paulini, M Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Plunkett, R Pondrom, L Produit, N Proudfoot, J Ptohos, F Punzi, G Ragan, K Rimondi, F Ristori, L RoachBellino, M Robertson, WJ Rodrigo, T Romano, J Rosenson, L Sakumoto, WK Saltzberg, D Sansoni, A Scarpine, V Schindler, A Schlabach, P Schmidt, EE Schmidt, MP Schneider, O Sciacca, GF Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Sgolacchia, A Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Smith, DA Snider, FD Song, L Song, T Spalding, J Spiegel, L Sphicas, P Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Stuart, D Sullivan, G Sumorok, K Swartz, RL Takahashi, T Takikawa, K Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, J Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Tollefson, K Tollestrup, A Tonnison, J deTroconiz, JF Tseng, J Turcotte, M Turini, N Uemura, N Ukegawa, F Unal, G vandenBrink, SC Vejcik, S Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wainer, N Walker, RC Wang, C Wang, CH Wang, G Wang, J Wano, MJ Wang, QF Warburton, A Watts, G Watts, T Webb, R Wei, C Wendt, W Wenzel, H Wester, WC Westhusing, T Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Wolinski, J Wu, DY Wu, X Wyss, J Yagil, A Yao, L Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, S Zhang, W Zucchelli, S TI Search for the rare decay W-+/-->pi(+/-)+gamma SO PHYSICAL REVIEW LETTERS LA English DT Article ID LIMIT; COLLISIONS AB We have searched for the rare decay W-+/- --> pi(+/-) + gamma in 16.7 pb(-1) of data taken in proton-antiproton collisions at root s = 1.8 TeV with the CDF detector at Fermilab. We find one event consistent with subtraction, we find the ratio of partial widths to be Gamma(W-+/- --> pi(+/-) + gamma)/Gamma(W-+/- --> e(+/-) + nu) less than or equal to 2.0 X 10(-3) at the 95% confidence level. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV BOLOGNA,IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. BRANDEIS UNIV,WALTHAM,MA 02254. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60637. DUKE UNIV,DURHAM,NC 27708. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV ILLINOIS,URBANA,IL 61801. MCGILL UNIV,INST PARTICLE PHYS,MONTREAL,PQ H3A 2T8,CANADA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. OSAKA CITY UNIV,OSAKA 588,JAPAN. UNIV PADUA,IST NAZL FIS NUCL,I-35131 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. UNIV PITTSBURGH,PITTSBURGH,PA 15260. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. ROCKEFELLER UNIV,NEW YORK,NY 10021. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. ACAD SINICA,TAIPEI 11529,TAIWAN. SUPERCONDUCTING SUPER COLLIDER LAB,DALLAS,TX 75237. TEXAS A&M UNIV,COLLEGE STN,TX 77843. TEXAS TECH UNIV,LUBBOCK,TX 79409. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. YALE UNIV,NEW HAVEN,CT 06511. RP Abe, F (reprint author), NATL LAB HIGH ENERGY PHYS,KEK,TSUKUBA,IBARAKI 305,JAPAN. RI Vucinic, Dejan/C-2406-2008; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Kim, Soo-Bong/B-7061-2014; Paulini, Manfred/N-7794-2014; Tartarelli, Giuseppe Francesco/A-5629-2016; OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Paulini, Manfred/0000-0002-6714-5787; Tartarelli, Giuseppe Francesco/0000-0002-4244-502X; Wyss, Jeffery/0000-0002-8277-4012; Bertolucci, Sergio/0000-0003-1738-4736 NR 11 TC 6 Z9 6 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 15 PY 1996 VL 76 IS 16 BP 2852 EP 2857 DI 10.1103/PhysRevLett.76.2852 PG 6 WC Physics, Multidisciplinary SC Physics GA UF379 UT WOS:A1996UF37900007 ER PT J AU Schultz, DR Krstic, PS Reinhold, CO Wells, JC AF Schultz, DR Krstic, PS Reinhold, CO Wells, JC TI Ionization of hydrogen and hydrogenic ions by antiprotons SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANTIMATTER-ATOM COLLISIONS; CHARGE-EXCHANGE; PROTON IMPACT; HELIUM; SINGLE AB Presented here is a description of the ionization of hydrogen and hydrogenic ions by antiproton impact, based on very large scale numerical solutions of the time-dependent Schrodinger equation in three spatial dimensions and on analysis of the topology of the electronic eigenenergy surfaces in the plane of complex internuclear distance. Comparison is made with other theories and very recent measurements. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,INST THEORET ATOM & MOLEC PHYS,CAMBRIDGE,MA 02138. RP Schultz, DR (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831, USA. RI Wells, Jack/D-3675-2016; OI Wells, Jack/0000-0002-5083-3030; Reinhold, Carlos/0000-0003-0100-4962 NR 32 TC 72 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 APR 15 PY 1996 VL 76 IS 16 BP 2882 EP 2885 DI 10.1103/PhysRevLett.76.2882 PG 4 WC Physics, Multidisciplinary SC Physics GA UF379 UT WOS:A1996UF37900014 ER PT J AU GronbechJensen, N Bishop, AR Dominguez, D AF GronbechJensen, N Bishop, AR Dominguez, D TI Metastable filamentary vortex flow in thin film superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID TWO-DIMENSIONAL MODEL; FLUX-LINE LATTICE; II SUPERCONDUCTORS; SIMULATION AB We present simulations of vortex dynamics in amorphous two-dimensional thin film superconductors, using a new exact method to evaluate long-range interactions between vortices. We find that the onset of dissipation for increasing current is dominated by filamentary channels of flow which are stable in a finite range of bias current. This results in novel steps in the differential resistance, which are strongly history dependent. Our results are in good agreement with recent experiments on amorphous Mo77Ge23 superconducting thin films. RP GronbechJensen, N (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Dominguez, Daniel/E-9304-2016 OI Dominguez, Daniel/0000-0002-6204-0150 NR 21 TC 90 Z9 90 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 15 PY 1996 VL 76 IS 16 BP 2985 EP 2988 DI 10.1103/PhysRevLett.76.2985 PG 4 WC Physics, Multidisciplinary SC Physics GA UF379 UT WOS:A1996UF37900040 ER PT J AU Kang, WN Kim, DH Shim, SY Park, JH Hahn, TS Choi, SS Lee, WC Hettinger, JD Gray, KE Glagola, B AF Kang, WN Kim, DH Shim, SY Park, JH Hahn, TS Choi, SS Lee, WC Hettinger, JD Gray, KE Glagola, B TI Pinning strength dependence of mixed-state Hall effect in YBa2Cu3O7 crystals with columnar defects SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-KAPPA SUPERCONDUCTORS; VORTEX-GLASS TRANSITION; RESISTIVITY; FILMS; TEMPERATURES; BEHAVIOR; MOTION AB The mixed-state Hall effect of twinned YBa2Cu3O7 crystals after heavy-ion irradiation clearly showed that the strong pinning induced by columnar defects not only modifies the scaling behavior between the Hall resistivity and longitudinal resistivity, but affects the temperature dependence of the Hall conductivity. For the irradiated crystals, the scaling exponent at 4 T was found to be 1.5 +/- 0.1 compared to 2.0 +/- 0.2 for the unirradiated one. The temperature dependence of the Hall conductivity of the irradiated crystals exhibited a clear deviation from that of the unirradiated one at low temperatures. C1 YEUNGNAM UNIV, DEPT PHYS, KYUNGSAN 712749, SOUTH KOREA. SOOKMYUNG WOMANS UNIV, SEOUL 140742, SOUTH KOREA. ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439 USA. RP KOREA INST SCI & TECHNOL, APPL PHYS GRP, SEOUL 130650, SOUTH KOREA. NR 22 TC 61 Z9 61 U1 2 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 APR 15 PY 1996 VL 76 IS 16 BP 2993 EP 2996 DI 10.1103/PhysRevLett.76.2993 PG 4 WC Physics, Multidisciplinary SC Physics GA UF379 UT WOS:A1996UF37900042 ER PT J AU Xiong, X Wochner, P Moss, SC Cao, Y Koga, K Fujita, M AF Xiong, X Wochner, P Moss, SC Cao, Y Koga, K Fujita, M TI Evidence of in-plane superstructure formation in phase-separated and staged single crystal La2CuO4+delta SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTING LA2CUO4+DELTA; ELECTROCHEMICAL OXIDATION AB In single crystal La2CuO4+delta, delta similar to 0.015, c-axis interstitial oxygen ordering (staging) in the oxygen-rich phase of the phase-separated sample was observed through satellite peaks in the neutron scattering at (0, 1, 4 +/- similar to 0.16) which first appear at 250 K. A superconducting T-c similar or equal to 31 K was achieved by prolonged annealing at 200 K of a staged crystal whose T-c was subsequently enhanced by similar to 1.5 K during a 7 h cooling from 215 to 190 K. This annealing below 215 K initiates a splitting of the staging satellites along the a* direction which signifies a one-dimensional modulation of the in-plane order. C1 UNIV HOUSTON,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77204. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. NATL INST ADV INTERDISCIPLINARY RES,TSUKUBA,IBARAKI 305,JAPAN. UNIV TSUKUBA,INST APPL PHYS,TSUKUBA,IBARAKI 305,JAPAN. RP Xiong, X (reprint author), UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204, USA. NR 20 TC 50 Z9 50 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 15 PY 1996 VL 76 IS 16 BP 2997 EP 3000 DI 10.1103/PhysRevLett.76.2997 PG 4 WC Physics, Multidisciplinary SC Physics GA UF379 UT WOS:A1996UF37900043 ER PT J AU Alman, DE Govier, RD AF Alman, DE Govier, RD TI Influence of Al additions on the reactive synthesis of MoSi2 SO SCRIPTA MATERIALIA LA English DT Article ID MOLYBDENUM DISILICIDE; ELEMENTAL POWDERS; COMPOSITES; SILICIDES RP Alman, DE (reprint author), US BUR MINES,ALBANY RES CTR,ALBANY,OR 97321, USA. NR 29 TC 9 Z9 11 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD APR 15 PY 1996 VL 34 IS 8 BP 1287 EP 1293 DI 10.1016/1359-6462(95)00655-9 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TZ629 UT WOS:A1996TZ62900016 ER PT J AU Saigal, A Leisk, GG Misture, ST Hubbard, CR AF Saigal, A Leisk, GG Misture, ST Hubbard, CR TI Neutron diffraction measurements of residual strains in tungsten fiber-reinforced Kanthal composites SO SCRIPTA MATERIALIA LA English DT Article ID STRESSES C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Saigal, A (reprint author), TUFTS UNIV,DEPT MECH ENGN,MEDFORD,MA 02155, USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD APR 15 PY 1996 VL 34 IS 8 BP 1309 EP 1313 DI 10.1016/1359-6462(95)00669-9 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TZ629 UT WOS:A1996TZ62900019 ER PT J AU Kepler, RG Valencia, VS Jacobs, SJ McNamara, JJ AF Kepler, RG Valencia, VS Jacobs, SJ McNamara, JJ TI Exciton-exciton annihilation in poly(p-phenylenevinylene) films SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT Symposium on Charge Transport in Electronic Polymers - A Tribute to Esther Conwell and Her Accomplishments CY MAY 05, 1995 CL ROCHESTER, NY DE exciton-exciton annihilation; poly(p-phenylenevinylene); films AB We have measured the saturation of fluorescence intensity with increasing excitation intensity and the time dependence of fluorescence intensity decay at high excitation intensities in poly (p-phenylenevinylene) films. The experimental results are consistent with the hypothesis that exciton-exciton annihilation reduces the exciton lifetime at high exciton concentrations and that the exciton diffusion coefficient is quite high. We conclude that the lowest energy electronic transition creates a Frenkel exciton rather than a free-carrier pair in a band-to-band transition. RP Kepler, RG (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 13 TC 76 Z9 76 U1 1 U2 8 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 APR 15 PY 1996 VL 78 IS 3 BP 227 EP 230 DI 10.1016/0379-6779(96)80143-3 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA UU242 UT WOS:A1996UU24200008 ER PT J AU Ettedgui, E Razafitrimo, H Gao, Y Hsieh, BR Ruckman, MW AF Ettedgui, E Razafitrimo, H Gao, Y Hsieh, BR Ruckman, MW TI Schottky barrier formation at the Ca/poly(p-phenylene vinylene) interface and its role in tunneling at the interface SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT Symposium on Charge Transport in Electronic Polymers - A Tribute to Esther Conwell and Her Accomplishments CY MAY 05, 1995 CL ROCHESTER, NY DE Schottky barrier formation; interface; poly(p-phenylene vinylene); calcium ID LIGHT-EMITTING-DIODES; POLY(P-PHENYLENE VINYLENE); CONJUGATED POLYMERS; EFFICIENCY; EMISSION; SPECTRA; CA AB We have studied the formation of the Ca/poly(p-phenylene vinylene) (PPV) interface using X-ray photoelectron emission spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS). The rigid shift seen by XPS in the C(1s) core level spectra of PPV points clearly to charge transfer and Schottky barrier formation at the interface as a result of Ca deposition. The NEXAFS spectra suggest that charge transfer at the metal/polymer interface induces the formation of a bipolaron lattice at the interface. Taken together, these results imply that the metal/polymer interface is not rigid and that triangular barrier tunneling fails to take into account the effect of barrier formation. We propose a band bending modified tunneling model to explain charge transfer at the Ca/polymer interface. C1 XEROX CORP, WEBSTER, NY 14580 USA. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RP Ettedgui, E (reprint author), UNIV ROCHESTER, DEPT PHYS & ASTRON, ROCHESTER, NY 14627 USA. RI Gao, Yongli/N-8392-2015 OI Gao, Yongli/0000-0001-9765-5246 NR 50 TC 23 Z9 24 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD APR 15 PY 1996 VL 78 IS 3 BP 247 EP 252 DI 10.1016/0379-6779(96)80146-9 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA UU242 UT WOS:A1996UU24200011 ER PT J AU Shinar, J AF Shinar, J TI Trapped polarons, free polarons and triplet excitons in pi-conjugated polymer films and light-emitting diodes SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT Symposium on Charge Transport in Electronic Polymers - A Tribute to Esther Conwell and Her Accomplishments CY MAY 05, 1995 CL ROCHESTER, NY DE diodes; polarons; excitons; conjugated polymers; films ID DETECTED MAGNETIC-RESONANCE; OPTICAL SPECTROSCOPY; PHOTOEXCITED STATES; PRECURSOR-ROUTE; VINYLENE); POLY(PARAPHENYLENEVINYLENE); ELECTROLUMINESCENCE; DYNAMICS AB Recent optically detected magnetic resonance studies of poly(p-phenylene vinylenes) (PPVs) and poly(3-alkyl thiophenes) (P3ATs) suggest that excitation at visible wavelengths lambda(ex) largely generates trapped polarons and polaron pairs, but UV excitation and carrier injection in LEDs generate free polarons. The photoluminescence (PL)-enhancing polaron resonance at long lambda(ex) is attributed to non-radiative recombination of trapped polaron pairs, which reduces their population and consequently the rate at which they non-radiatively quench singlet excitons. Interchain coupling, some defects induced by structural disorder, and sites adjacent to C-60(-) counterions apparently enhance the generation of these trapped polarons as well as intersystem crossing from the singlet to the tripler manifold. At short lambda(ex) a PL-quenching polaron resonance emerges, and is assigned to fusion of photogenerated free polarons to bipolarons, which also quench singlet excitons. These interpretations imply that the 1(1)B(u) exciton binding energy, defined as its dissociation energy to free polarons, is the difference between the absorption edge and the excitation energy at which the PL-quenching polaron resonance emerges. This difference is similar to 0.8 eV in poly(2,5-dioctoxy-p-phenylene vinylene) and poly(3-hexyl thiophene). C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Shinar, J (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 45 TC 29 Z9 29 U1 1 U2 7 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 APR 15 PY 1996 VL 78 IS 3 BP 277 EP 284 DI 10.1016/0379-6779(96)80150-0 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA UU242 UT WOS:A1996UU24200015 ER PT J AU Young, KD Ozguner, U AF Young, KD Ozguner, U TI Co-states for sliding mode design in linear systems SO SYSTEMS & CONTROL LETTERS LA English DT Article DE sliding mode; variable structure systems; robust control; discrete time control ID DISCRETE AB A control design for linear systems with uncertainties is presented where a particular time-varying sliding mode manifold is specified utilizing co-states of the plant. We introduce design methods for both continuous time and sampled data systems. It is shown that robustness of the closed-loop systems with continuous time control degrades when an equivalent sampled data control is used. C1 OHIO STATE UNIV,DEPT ELECT ENGN,COLUMBUS,OH 43210. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RI Ozguner, Umit/A-4523-2008 NR 12 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6911 J9 SYST CONTROL LETT JI Syst. Control Lett. PD APR 15 PY 1996 VL 27 IS 4 BP 233 EP 242 PG 10 WC Automation & Control Systems; Operations Research & Management Science SC Automation & Control Systems; Operations Research & Management Science GA UN196 UT WOS:A1996UN19600004 ER PT J AU Ghislotti, G Nielsen, B AsokaKumar, P Lynn, KG Szeles, C Bottani, CE Bertoni, S Cerofolini, GF Meda, L AF Ghislotti, G Nielsen, B AsokaKumar, P Lynn, KG Szeles, C Bottani, CE Bertoni, S Cerofolini, GF Meda, L TI Characterization of silicon-implanted SiO2 layers using positron annihilation spectroscopy SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Symposium I on Porous Silicon - Material, Technology and Devices, at the European-Materials-Research-Society 1995 Spring Conference CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP European Mat Res Soc DE silicon; ion implantation; silicon dioxide; transmission electron microscopy ID INTERFACE AB Silicon-implanted thermal SiO2 layers were studied using depth-resolved positron annihilation spectroscopy (PAS) and transmission electron microscopy (TEM). TEM observations show the presence of silicon nanocrystals (Si-nc) in the region between 200 nm and 300 nm. The defect annealing behavior is studied by means of PAS. For 1 000 degrees C annealed samples at a depth for which Si-nc are observed, a distinctive PAS signal is detected and ascribed to the Si-nc/SiO2 interface. C1 POLITECN MILAN,I-20133 MILAN,ITALY. IST GUIDO DONEGANI SPA,I-28100 NOVARA,ITALY. RP Ghislotti, G (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Nielsen, Bent/B-7353-2009; OI Nielsen, Bent/0000-0001-7016-0040; Bottani, Carlo Enrico/0000-0002-2015-7043 NR 18 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 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD APR 15 PY 1996 VL 276 IS 1-2 BP 310 EP 313 DI 10.1016/0040-6090(95)08105-4 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA UU268 UT WOS:A1996UU26800080 ER PT J AU Melnick, RL Elwell, MR Roycroft, JH Chou, BJ Ragan, HA Miller, RA AF Melnick, RL Elwell, MR Roycroft, JH Chou, BJ Ragan, HA Miller, RA TI Toxicity of inhaled chloroprene (2-chloro-1,3-butadiene) in F344 rats and B6C3F(1) mice SO TOXICOLOGY LA English DT Article DE chloroprene; butadiene; inhalation toxicology; hepatocellular necrosis; anemia; olfactory epithelial degeneration ID INHALATION EXPOSURE; 1,3-BUTADIENE; CARCINOGENICITY; TOXICOLOGY; ISOPRENE; TISSUE; RODENT AB Chloroprene (2-chloro-1,3-butadiene) is a high production chemical used almost exclusively in the production of polychloroprene (neoprene) elastomer. Because of its structural similarity to isoprene (2-methyl-1,3-butadiene) and to 1,3-butadiene, a potent trans-species carcinogen, inhalation studies were performed on chloroprene to characterize its toxicological potential and to provide a basis for selecting exposure concentrations for chronic toxicity and carcinogenicity studies. Thirteen-week inhalation toxicology studies were conducted in male and female F344 rats and B6C3F(1) mice at exposure concentrations of 0, 5, 12, 32 or 80 ppm (6 h/day; 5 days/week). A 200 ppm exposure group was also included for rats only, because a previous study showed that this concentration of chloroprene is lethal to mice. In mice, exposure to 80 ppm chloroprene caused a marginal decrease in body weight gain in males and epithelial hyperplasia of the forestomach in males and females. This lesion has been observed in mice exposed to isoprene or 1,3-butadiene. In rats, exposure to 80 ppm chloroprene or higher concentrations caused degeneration and metaplasia of the olfactory epithelium and exposure to 200 ppm caused anemia, hepatocellular necrosis and reduced sperm motility. These lesions have not been observed in rats exposed to isoprene or 1,3-butadiene. The profile of toxic effects of chloroprene is considerably different from that of isoprene or 1,3-butadiene; this may be due to differences in exposure concentrations that were used in toxicology studies of these compounds and/or to the influence of the chlorine substitution on the toxicokinetics of these compounds, on their biotransformation, or on the reactivity of metabolic intermediates with tissue macromolecules. C1 NIEHS, RES TRIANGLE PK, NC 27709 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 36 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0300-483X J9 TOXICOLOGY JI Toxicology PD APR 15 PY 1996 VL 108 IS 1-2 BP 79 EP 91 DI 10.1016/0300-483X(95)03286-O PG 13 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA UC593 UT WOS:A1996UC59300011 PM 8644121 ER PT J AU Fraga, CG Motchnik, PA Wyrobek, AJ Rempel, DM Ames, BN AF Fraga, CG Motchnik, PA Wyrobek, AJ Rempel, DM Ames, BN TI Smoking and low antioxidant levels increase oxidative damage to sperm DNA SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE 8-oxo-deoxyguanosine; ascorbate; tocopherol ID ASCORBIC-ACID; MUTATION; CANCER AB Our previous studies have shown that men with low ascorbate intake have markedly increased oxo(8)dG in the DNA of their sperm. Because cigarette smoke is high in oxidants and depletes plasma and tissue antioxidants, oxidative DNA damage in sperm and tocopherol and ascorbate levels in seminal plasma were determined in smokers and non-smokers. The level in sperm DNA of oxo(8)dG, an oxidative lesion of guanine, was 50% higher in smokers compared to non-smokers (p = 0.005). The concentration of cr-tocopherol in seminal plasma was decreased in smokers by 32% (p = 0.03). Smoking and low antioxidant levels increase oxidative damage to sperm DNA. We discuss the possibility that paternal smoking causes mutations in sperm that lead to cancer, birth defects, and genetic diseases in offspring. C1 UNIV CALIF BERKELEY, DIV BIOCHEM & MOLEC BIOL, BERKELEY, CA 94720 USA. UNIV BUENOS AIRES, FAC FARM & BIOQUIM, RA-1113 BUENOS AIRES, DF, ARGENTINA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. UNIV CALIF SAN FRANCISCO, DIV ENVIRONM & OCCUPAT MED, SAN FRANCISCO, CA 94143 USA. RI Rempel, David/E-8424-2013 FU NCI NIH HHS [CA39910]; NIEHS NIH HHS [ESO1896] NR 20 TC 284 Z9 296 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD APR 13 PY 1996 VL 351 IS 2 BP 199 EP 203 DI 10.1016/0027-5107(95)00251-0 PG 5 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA UK631 UT WOS:A1996UK63100014 PM 8622715 ER PT J AU Laskin, J Behm, JM Lykke, KR Lifshitz, C AF Laskin, J Behm, JM Lykke, KR Lifshitz, C TI Time-resolved appearance energies for fragment ions from C-60 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID RESILIENCE AB Time-resolved appearance energies (AEs) were determined for C-58(+) and C-56(+) by electron ionization of C-60. Two methods were applied: (1) electron-space-charge trapping in the ion source of a tandem mass spectrometer and (2) Fourier transform mass spectrometry in an ion cyclotron resonance spectrometer. The AE for C-58(+) obtained in the limit of long ion trapping time at an evaporation temperature of 620 K is 44 +/- 2 eV. This corresponds to a minimum intrinsic kinetic shift, IS = 30.4 eV due to radiative decay and agrees with recent results that cooling of C-60 (and C-60(+),) is dominated by black-body radiative decay below an internal temperature of 2300 K. C1 HEBREW UNIV JERUSALEM,FRITZ HABER RES CTR MOLEC DYNAM,IL-91904 JERUSALEM,ISRAEL. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP Laskin, J (reprint author), HEBREW UNIV JERUSALEM,DEPT PHYS CHEM,IL-91904 JERUSALEM,ISRAEL. RI Laskin, Julia/H-9974-2012 OI Laskin, Julia/0000-0002-4533-9644 NR 19 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 12 PY 1996 VL 252 IS 3-4 BP 277 EP 280 DI 10.1016/0009-2614(96)00143-1 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UG843 UT WOS:A1996UG84300018 ER PT J AU Sharma, PK Kuchumov, AR Chottard, G Martin, PD Wall, JS Vinogradov, SN AF Sharma, PK Kuchumov, AR Chottard, G Martin, PD Wall, JS Vinogradov, SN TI The role of the dodecamer subunit in the dissociation and reassembly of the hexagonal bilayer structure of Lumbricus terrestris hemoglobin SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID GIANT EXTRACELLULAR HEMOGLOBIN; AMINO-ACID-SEQUENCES; QUATERNARY STRUCTURE; REASSOCIATION; MYOGLOBIN; PROTEIN; PH; ALKYLUREAS; EARTHWORM; TRIMER AB The dissociation of the similar to 3500-kDa hexagonal bilayer (HBL) hemoglobin (Db) of Lumbricus terrestris upon exposure to Gdm salts, urea and the heteropolytungstates [SiW11O39](8-) (SiW), [NaSb9W21O86](18-) (SbW) and [BaAs4W40O140](27-) (AsW) at neutral pH was followed by gel filtration, SDS-polyacrylamide gel electrophoresis, and scanning transmission electron microscopy. Elution curves were fitted to sums of exponentially modified gaussians to represent the peaks due to undissociated oxyHb, D (similar to 200 kDa), T+L (similar to 50 kDa), and M (similar to 25 kDa) (T = disulfide-bonded trimer of chains a-c, M = chain d, and L = linker chains). OxyHb dissociation decreased in the order Gdm . SCN > Gdm . Cl > urea > Gdm . OAc and AsW > SbW > SiW. Scanning transmission electron microscopy mass mapping of D showed similar to 10-nm particles with masses of 200 kDa, suggesting them to be dodecamers (a + b + c)(3)d(3). OxyHb dissociations in urea and Gdm . Cl and at alkaline pH could be fitted only as sums of 3 exponentials. The time course of D was bell-shaped, indicating it was an intermediate. Dissociations in SiW and upon conversion to metHb showed only two phases. The kinetic heterogeneity may be due to oxyHb structural heterogeneity. Formation of D was spontaneous during HBL reassembly, which was minimal (less than or equal to 10%) without Group IIA cations. During reassembly, maximal (similar to 60%) at 10 mM cation, D occurs at constant levels (similar to 15%), implying the dodecamer to be an intermediate. C1 WAYNE STATE UNIV,SCH MED,DEPT BIOCHEM & MOLEC BIOL,DETROIT,MI 48201. UNIV PARIS 06,CHIM MET TRANSIT LAB,URA 419,F-75252 PARIS,FRANCE. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. FU NCRR NIH HHS [RR01777]; NIDDK NIH HHS [DK38674] NR 42 TC 34 Z9 34 U1 0 U2 3 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 12 PY 1996 VL 271 IS 15 BP 8754 EP 8762 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UE730 UT WOS:A1996UE73000041 PM 8621510 ER PT J AU Zal, F Lallier, FH Wall, JS Vinogradov, SN Toulmond, A AF Zal, F Lallier, FH Wall, JS Vinogradov, SN Toulmond, A TI The multi-hemoglobin system of the hydrothermal vent tube worm Riftia pachyptila .1. Reexamination of the number and masses of its constituents SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID TRANSMISSION ELECTRON-MICROSCOPE; LUMBRICUS-TERRESTRIS HEMOGLOBIN; SUBUNIT STRUCTURE; EXTRACELLULAR HEMOGLOBIN; ANNELID HEMOGLOBIN; SULFIDE-BINDING; GALAPAGOS RIFT; JONES; BLOOD; VESTIMENTIFERA AB The deep-sea tube worm Riftia pachyptila Jones possesses a well developed circulatory system and a large coelomic compartment, both containing extracellular hemoglobins, Fresh vascular blood is heterogeneous and contains two different hemoglobins (V1 and V2), whereas the coelomic fluid is homogeneous and comprises only one hemoglobin (C1), Their molecular weights have been determined by scanning transmission electron microscopy mass mapping (STEM) and by multi-angle laser light scattering (MALLS). Both methods yielded approximately the same molecular weights with masses significantly higher than the literature data for V1, V1, V2, and C1 had M(r) of 3396 +/- 540 x 10(3), 393 +/- 71 x 10(3), and 410 +/- 51 x 10(3) by STEM, and 3503 +/- 13 x 10(3), 433 +/- 8 x 10(3), and 380 +/- 4 x 10(3) by MALLS, respectively, Transmission electron micrographs of V1 are typical of an hexagonal bilayer hemoglobin (HBL Hb), When submitted to dilution or osmotic shock, V1 dissociates into halves and one-twelfth subunits like annelid HBL Hbs, V1 is resistant to urea treatment, indicating that hydrophobic interactions play a small role in its quaternary structure, Conversely, V1 Hb is rather unstable in solution without denaturant, a property which seems to be characteristic of vestimentiferan HBL Hbs and could be explained by an important number of hydrogen bonds. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. WAYNE STATE UNIV,SCH MED,DEPT BIOCHEM,DETROIT,MI 48201. RP Zal, F (reprint author), UNIV PARIS 06,CNRS,INSU,EQUIPE ECOPHYSIOL,BIOL STN,PL GEORGES TEISSIER,BP 74,F-29682 ROSCOFF,FRANCE. FU NIDDK NIH HHS [DK38674] NR 33 TC 47 Z9 49 U1 0 U2 6 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD APR 12 PY 1996 VL 271 IS 15 BP 8869 EP 8874 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UE730 UT WOS:A1996UE73000059 PM 8621528 ER PT J AU Covey, C AF Covey, C TI Sun-climate links SO SCIENCE LA English DT Letter RP Covey, C (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 12 PY 1996 VL 272 IS 5259 BP 179 EP 179 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UE729 UT WOS:A1996UE72900002 ER PT J AU Rutherford, PH AF Rutherford, PH TI The ITER project SO SCIENCE LA English DT Letter C1 MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. RP Rutherford, PH (reprint author), PRINCETON PLASMA PHYS LAB,ITER TECH ADVISORY COMM,PRINCETON,NJ 08543, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 12 PY 1996 VL 272 IS 5259 BP 181 EP 181 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UE729 UT WOS:A1996UE72900006 ER PT J AU Sassi, AP Lee, SH Park, YH Blanch, HW Prausnitz, JM AF Sassi, AP Lee, SH Park, YH Blanch, HW Prausnitz, JM TI Sorption of lysozyme by HEMA copolymer hydrogels SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article ID SOFT CONTACT-LENSES; PROTEIN ADSORPTION; TEAR PROTEINS; DEPOSITS; SURFACE; WEARERS AB Sorption of lysozyme by 2-hydroxyethyl methacrylate (HEMA) copolymer hydrogels was studied as a function of pH and gel composition. Three types of HEMA gels were synthesized: neutral (HEMA), acidic (HEMA + acrylic acid), and basic (HEMA + dimethylaminoethyl methacrylate). Each gel was synthesized at four initial volume fractions to obtain different equilibrium swelling ratios and microstructures. Sorption as a function of time was measured for each gel at pH 7, 7.5, and 8. The rate of uptake by the acidic gels was more rapid than that by the neutral gels: To sorb 90% of the protein required only 1 h for the acidic gels but 15 days for neutral gels. Lysozyme did not adsorb or partition into the basic gels. The fractional approach to equilibrium was most rapid for the more swollen gels, and the effect of pH was small. The results reported here may be useful for rational design of new biomaterials where it is desirable to know the relative magnitude of the effects of composition, synthesis, and pH on protein sorption. (C) 1996 John Wiley & Sons, Inc. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 50 TC 12 Z9 12 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD APR 11 PY 1996 VL 60 IS 2 BP 225 EP 234 DI 10.1002/(SICI)1097-4628(19960411)60:2<225::AID-APP10>3.0.CO;2-4 PG 10 WC Polymer Science SC Polymer Science GA UA028 UT WOS:A1996UA02800010 ER PT J AU Maurice, D HeadGordon, M AF Maurice, D HeadGordon, M TI On the nature of electronic transitions in radicals: An extended single excitation configuration interaction method SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article; Proceedings Paper CT International Conference on Molecular Quantum Mechanics - Methods and Applications, in Memory of Samuel Francis Boys and in Honor of Isaiah Shavitt CY SEP 03-07, 1995 CL UNIV CAMBRIDGE, CAMBRIDGE, ENGLAND HO UNIV CAMBRIDGE ID EXCITED-STATES; ENERGIES; BENZYL; SPECTROSCOPY; SPECTRA AB We propose that the generalization of pure spin single reference excited state theories from molecules with closed shell ground states to radicals be based on a redefinition of the meaning of excitation levels. Open shell single substitutions are expanded to include spin-adapted double excitations which traverse the singly occupied orbitals. These excitations are deleted from the expanded open shell double substitutions, which include the corresponding spin-adapted triple substitutions (e.g., a pair of the excitations traverses the singly occupied orbitals), etc. Applied to single excitation configuration interaction (CIS), this approach defines a spin-adapted extended CIS (XCIS) theory for the excited states of radicals. XCIS is size consistent and variational and has computational complexity that scales in the same way as CIS with molecular size. More low-lying excited states of radicals are correctly described by XCIS than by the restricted open shell CIS method. This is demonstrated by calculations on excited states of seven diatomic radicals and the methyl, nitromethyl, benzyl, phenoxyl, and anilino radicals. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 35 TC 58 Z9 58 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 11 PY 1996 VL 100 IS 15 BP 6131 EP 6137 DI 10.1021/jp952754j PG 7 WC Chemistry, Physical SC Chemistry GA UE695 UT WOS:A1996UE69500020 ER PT J AU Ivanic, J Ruedenberg, K AF Ivanic, J Ruedenberg, K TI Rotation matrices for real spherical harmonics. Direct determination by recursion SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article; Proceedings Paper CT International Conference on Molecular Quantum Mechanics - Methods and Applications, in Memory of Samuel Francis Boys and in Honor of Isaiah Shavitt CY SEP 03-07, 1995 CL UNIV CAMBRIDGE, CAMBRIDGE, ENGLAND HO UNIV CAMBRIDGE AB A recurrence procedure is derived for constructing the rotation matrices between real spherical harmonics directly in terms of the elements of the original 3x3 rotation matrix without the intermediary of any parameters. The procedure furnishes a simple, efficient, and general method for the formal as well as numerical evaluation of these representation matrices. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP Ivanic, J (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 13 TC 51 Z9 52 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 11 PY 1996 VL 100 IS 15 BP 6342 EP 6347 DI 10.1021/jp953350u PG 6 WC Chemistry, Physical SC Chemistry GA UE695 UT WOS:A1996UE69500051 ER PT J AU Ringbom, A Tibell, G Zorro, R Blomgren, J Conde, H Elmgren, K Hultqvist, S Nilsson, J Olsson, N Fahlander, C Nilsson, L Nyberg, J Reistad, D Renberg, PU Westerberg, L Likar, A Wender, S AF Ringbom, A Tibell, G Zorro, R Blomgren, J Conde, H Elmgren, K Hultqvist, S Nilsson, J Olsson, N Fahlander, C Nilsson, L Nyberg, J Reistad, D Renberg, PU Westerberg, L Likar, A Wender, S TI A facility for studies of giant multipole resonances by fast heavy-ion scattering SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID DIPOLE RESONANCE; EXCITATION; PB-208; DECAY AB A technique to study giant resonances by heavy-ion scattering in the energy range 100A-470A MeV using one quadrant of the CELSIUS storage ring as a spectrometer is presented. A test experiment using 250A MeV O-16 On a Ar-40 target has been performed. Thez inelastically scattered particles could be separated from the background originating from the beam halo using a focal-plane telescope in coincidence with neutron detectors around the target. The resolution in the excitation-energy spectrum was 3.5+/-0.5 MeV, mainly determined by the beam size at the target. C1 UNIV UPPSALA,SVEDBERG LAB,S-75121 UPPSALA,SWEDEN. UNIV UPPSALA,DEPT RADIAT SCI,S-75121 UPPSALA,SWEDEN. UNIV UPPSALA,DEPT NEUTRON RES,S-75121 UPPSALA,SWEDEN. JOZEF STEFAN INST,LJUBLJANA,SLOVENIA. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. NR 22 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 1996 VL 373 IS 1 BP 57 EP 64 DI 10.1016/0168-9002(95)01494-2 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ927 UT WOS:A1996UJ92700010 ER PT J AU Hildner, ML Antolak, AJ Bench, GS AF Hildner, ML Antolak, AJ Bench, GS TI Improved fitting of PIXE spectra: The voigt profile and Si(Li) detector modeling SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID X-RAY-DETECTORS; MONTE-CARLO SIMULATION; EFFICIENCY DETERMINATION; ENERGY-RANGE; LINESHAPES AB The true emitted X-ray lineshape as measured by a Si(Li) detector is the convolution of the intrinsic Lorentzian X-ray lineshape and the detector response function. We demonstrate the necessity of using the Voigt profile - the convolution of a Lorentzian and a Gaussian- to fit the full-energy peak portion of directly measured X-ray lines. By incorporating the Voigtian in our PIXE spectrum fitting code, PIXEF, we have found consistent improvement in the quality of fit and calculated elemental yields. We have also found that the Voigtian fit is required to give an accurate ratio of tail to peak intensity. We attribute the tail to a surface layer of incomplete charge collection (ICC) at the front of the detector. Although this model is improved by appropriately accounting for the loss of photoelectrons that travel back to the ICC layer after bring emitted from the intrinsic region, it appears to fail when the full-energy peak is fit to a Gaussian. On the other hand, excellent agreement between the improved model and experiment is found when the full-energy peak is fit to a Voigtian. C1 SANDIA NATL LABS,LIVERMORE,CA 94551. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 25 TC 3 Z9 3 U1 2 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 1996 VL 373 IS 1 BP 124 EP 130 DI 10.1016/0168-9002(95)01388-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ927 UT WOS:A1996UJ92700021 ER PT J AU Brown, D Olsher, RH Eisen, Y Rodriguez, JF AF Brown, D Olsher, RH Eisen, Y Rodriguez, JF TI A real-time pulsed photon dosimeter SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SCINTILLATORS AB Radiation sources producing short pulses of photon radiation are now widespread. Such sources include election and proton linear accelerators, betatrons, synchrotrons, and field-emission impulse generators. It is often desirable to measure leakage and skyshine radiation from such sources in real time, on a single-pulse basis as low as 8.7 nGy (1 mu R) per pulse. This paper describes the design and performance of a prototype, real-time, pulsed photon dosimeter (PPD) capable of single-pulse dose measurements over the range from 3.5 nGy to 3.5 mu Gy (0.4 to 400 mu R). The PPD may also be operated in a multiple-pulse mode that integrates the dose from a train of radiation pulses over a 3-s period. A pulse repetition rate of up to 300 Hz is accommodated. The design is eminently suitable for packaging as a lightweight, portable, survey meter. The PPD uses a CdWO4 scintillator optically coupled to a photodiode to generate a charge at the diode output. A pulse amplifier converts the char ge to a voltage pulse. A digitizer circuit generates a burst of logic pulses whose number is proportional to the peak value of the voltage pulse. The digitizer output is recorded by a pulse counter and suitably displayed. A prototype PPD was built for testing and evaluation purposes. The performance of the PPD was evaluated with a variety of pulsed photon sources. The dynamic range, energy response, and response to multiple pulses were characterized. The experimental data confirm the viability of the PPD for pulsed photon dosimetry. C1 UNIV CALIF LOS ALAMOS NATL LAB,HLTH PHYS MEASUREMENTS GRP,LOS ALAMOS,NM 87544. SOREQ NUCL RES CTR,IL-70600 YAVNE,ISRAEL. NR 7 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 1996 VL 373 IS 1 BP 139 EP 147 DI 10.1016/0168-9002(95)01439-X PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ927 UT WOS:A1996UJ92700024 ER PT J AU Naya, JE vonBallmoos, P Smither, RK Faiz, M Fernandez, PB Graber, T Albernhe, F Vedrenne, G AF Naya, JE vonBallmoos, P Smither, RK Faiz, M Fernandez, PB Graber, T Albernhe, F Vedrenne, G TI Experimental results obtained with the positron-annihilation-radiation telescope of the Toulouse-Argonne collaboration SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We present laboratory measurements obtained with a ground-based prototype of the focusing position-annihilation-radiation telescope developed by the Toulouse-Argonne collaboration. This instrument has been designed to collect 511-keV photons from astrophysical sources when operating as a balloon borne observatory. The ground-based prototype consists of a crystal lens holding small cubes of diffracting germanium crystals and a 3 x 3 germanium array that detects the concentrated beam in the focal plane. Measured performances of the instrument at different line energies (511 and 662 keV) are presented and compared with Monte Carlo simulations; also the advantages of combining the lens with a detector array are discussed. The results obtained in the laboratory have strengthened interest in a crystal-diffraction telescope: the balloon instrument will provide a combination of high spatial and energy resolution (15 are sec and 2 keV, respectively) with an extremely low instrumental background resulting in a sensitivity of similar to 3 x 10(-5) photons cm(-2) s(-1). These features will allow us to resolve a possible narrow 511-keV line both energetically and spatially within a Galactic center ''microquasar'' or in other broad-class annihilators. C1 CTR ETUD SPATIALE RAYONNEMENTS,F-31029 TOULOUSE,FRANCE. ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439. NR 4 TC 15 Z9 15 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 APR 11 PY 1996 VL 373 IS 1 BP 159 EP 164 DI 10.1016/0168-9002(95)01476-4 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ927 UT WOS:A1996UJ92700027 ER PT J AU Boggild, H Boissevain, J Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Fields, DE Franz, A Gaardhoje, JJ Hansen, O Hardtke, D vanHecke, H Holzer, EB Humanic, T Hummel, P Jacak, BV Jayanti, R Kaneta, M Kopytine, M Leltchouk, M Ljubicic, T Lorstad, B Maeda, N Medvedev, A Murray, M Nishimura, S Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Sakaguchi, A SimonGillo, J SchmidtSorensen, J Sondheim, W Spegel, M Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, K Xu, N Zachary, D AF Boggild, H Boissevain, J Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Fields, DE Franz, A Gaardhoje, JJ Hansen, O Hardtke, D vanHecke, H Holzer, EB Humanic, T Hummel, P Jacak, BV Jayanti, R Kaneta, M Kopytine, M Leltchouk, M Ljubicic, T Lorstad, B Maeda, N Medvedev, A Murray, M Nishimura, S Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Sakaguchi, A SimonGillo, J SchmidtSorensen, J Sondheim, W Spegel, M Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, K Xu, N Zachary, D TI Coulomb effect in single particle distributions SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEAR COLLISIONS; PIONS AB Single particle distributions from heavy-ion collisions show the effect of Coulomb interactions on the final state. While a rather strong effect is seen in the ratio pi(-)/pi(+) from central 158A . GeV/c Pb+Pb collisions, at most a small enhancement is found in the ratios from S+S and S+Pb collisions at 200A . GeV/c. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. NUCL PHYS LAB NANTES,F-44072 NANTES,FRANCE. HIROSHIMA UNIV,HIGASHIHIROSHIMA 739,JAPAN. CERN,CH-1211 GENEVA 23,SWITZERLAND. RUDJER BOSKOVIC INST,ZAGREB,CROATIA. OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. VIENNA TECH UNIV,A-1040 VIENNA,AUSTRIA. LUND UNIV,DEPT PHYS,S-22362 LUND,SWEDEN. TEXAS A&M UNIV,COLLEGE STN,TX 77843. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Boggild, H (reprint author), NIELS BOHR INST,DK-2100 COPENHAGEN,DENMARK. OI Gaardhoje, Jens-Jorgen/0000-0001-6122-4698 NR 24 TC 28 Z9 28 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 11 PY 1996 VL 372 IS 3-4 BP 339 EP 342 DI 10.1016/0370-2693(96)00114-1 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UF997 UT WOS:A1996UF99700025 ER PT J AU Alcock, C Allsman, RA Axelrod, TS Bennett, DP Cook, KH Freeman, KC Griest, K Guern, JA Lehner, MJ Marshall, SL Park, HS Perlmutter, S Peterson, BA Pratt, MR Quinn, PJ Rodgers, AW Stubbs, CW Sutherland, W AF Alcock, C Allsman, RA Axelrod, TS Bennett, DP Cook, KH Freeman, KC Griest, K Guern, JA Lehner, MJ Marshall, SL Park, HS Perlmutter, S Peterson, BA Pratt, MR Quinn, PJ Rodgers, AW Stubbs, CW Sutherland, W TI The MACHO project first-year large Magellanic Cloud results: The microlensing rate and the nature of the Galactic dark halo SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; Galaxy, halo; gravitational lensing; Magellanic Clouds; stars, low-mass, brown dwarfs ID OBJECTS; STARS; MATTER; GALAXY; BRIGHT; MASS AB Since July 1992, the MACHO project has been carrying out long-term photometric monitoring of over 20 million stars in the Magellanic Clouds and Galactic bulge. Our aim is to search for the very rare gravitational microlensing events predicted if the dark halo of our Galaxy is comprised of massive compact halo objects (hereafter MACHOs). We have now analyzed most of the first year's LMC data, comprising 9.5 million light curves of stars with an average of 235 observations each. Automated selection procedures applied to this sample show three events consistent with microlensing; the first detected is very striking (Alcock and coworkers), and two are of modest amplitude. We have evaluated our experimental detection efficiency using a range of detailed Monte Carlo simulations, including the addition of artificial stars to real data frames. Using a ''standard'' halo density profile, we find that a halo comprised entirely of MACHOs in the mass range 3 x 10(-4) to 0.06 M(.) would predict more than 15 detected events in this data set, and objects around 3 x 10(-3) M(.) would predict 25 events; thus a standard spherical halo cannot be dominated by objects in this mass range. Assuming all three events are microlensing by halo objects, and fitting a naive spherical halo model to our data yields a MACHO halo fraction f = 0.19(-0.10)(+0.16), a total mass in MACHOs (inside 50 kpc) of 7.6(-4)(+6) x 10(10) M(.), and a microlensing optical depth 8.8(-5)(+7) x 10(-8) (68% confidence level). Should only one of these events be microlensing, this could be explained in terms of previously known populations. We have explored a wide range of halo models and find that, while our constraints on the MACHO fraction are quite model dependent, constraints on the total mass in MACHOs within 50 kpc are quite secure. Future observations from this and other similar projects, and accurate measurements of the Galactic mass out to large radii, should combine to give much improved constraints on the MACHO fraction of the halo. C1 UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. AUSTRALIAN NATL UNIV,SUPERCOMP FACIL,CANBERRA,ACT 0200,AUSTRALIA. AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,WESTON,ACT 2611,AUSTRALIA. UNIV CALIF SAN DIEGO,DEPT PHYS,SAN DIEGO,CA 92093. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. UNIV WASHINGTON,DEPT PHYS & ASTRON,SEATTLE,WA 98195. UNIV OXFORD,DEPT PHYS,OXFORD OX1 3RH,ENGLAND. RP Alcock, C (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. RI Stubbs, Christopher/C-2829-2012; Quinn, Peter/B-3638-2013; Bennett, David/O-2136-2013; Perlmutter, Saul/I-3505-2015 OI Stubbs, Christopher/0000-0003-0347-1724; Bennett, David/0000-0001-8043-8413; Perlmutter, Saul/0000-0002-4436-4661 NR 58 TC 139 Z9 139 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1996 VL 461 IS 1 BP 84 EP & DI 10.1086/177039 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UD646 UT WOS:A1996UD64600006 ER PT J AU Moran, EC Helfand, DJ Becker, RH White, RL AF Moran, EC Helfand, DJ Becker, RH White, RL TI The Einstein two-sigma catalog: Silver needles in the X-ray haystack SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; galaxies, active; methods, data analysis; X-rays, galaxies ID N-LOG-S; MEDIUM-SENSITIVITY SURVEY; HOT INTERSTELLAR-MEDIUM; ACTIVE GALACTIC NUCLEI; EMISSION-LINE GALAXIES; BL LACERTAE OBJECTS; OPTICAL SPECTROSCOPY; SEYFERT-GALAXIES; SKY SURVEY; COSMOLOGICAL EVOLUTION AB To facilitate the study of X-ray sources fainter than those contained in the Einstein Medium-Sensitivity Survey (EMSS), we have constructed a new catalog of sources and fluctuations exceeding 2 sigma significance in 2520 high-latitude Einstein IPCC images. We have employed various tests to validate our source-search algorithm for both high- and low-significance sources, and to identify and remove the small number of spurious sources induced by our detection procedure. Based on the known vignetting and background characteristics of the IPC and the measured X-ray log N-log S relation, we have modeled the number of real sources expected in the catalog in order to evaluate its statistical properties below 4 sigma significance. Our modeling suggests that similar to 13,000 sources in the catalog are real celestial X-ray sources, an increase of similar to 9100 over the number found in previous analyses of the same IPC images. We find that not only is the reliability of the Two-Sigma Catalog a function of source significance sigma, it is a function of off-axis angle on the detector as well. The application of different signal-to-noise thresholds at different off-axis angles thus enables one to tune the reliability of the catalog. The chief motivation for studying large numbers of faint X-ray sources is to search for possible new components of the cosmic X-ray background. To select out real celestial X-ray sources in the Two-Sigma Catalog, we apply astronomical catalogs at other wavelengths as filters. For example, the cross-correlation of the Two-Sigma Catalog with catalogs from surveys of the radio and infrared sky has yielded large samples of faint X-ray sources that are similar to 90% reliable. Optical spectroscopy of 77 unidentified faint X-ray sources has turned up several surprises, illustrating the merits of selecting X-ray sources using a variety of methods: high-redshift quasars (one at z = 4.30), which are absent in the EMSS, X-ray-luminous (L(X) approximate to 10(43) ergs s(-1)) radio-loud elliptical galaxies with optical spectra devoid of emission lines, and infrared-bright active galactic nuclei whose optical spectra are dominated by starburst galaxy features. Follow-up observations are scheduled to determine whether any of these types of objects represent a previously unrecognized component of the X-ray background. C1 COLUMBIA UNIV,DEPT ASTRON,NEW YORK,NY 10027. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP Moran, EC (reprint author), LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550, USA. NR 74 TC 34 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 APR 10 PY 1996 VL 461 IS 1 BP 127 EP & DI 10.1086/177042 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UD646 UT WOS:A1996UD64600009 ER PT J AU Liu, MC Graham, JR Ghez, AM Meixner, M Arens, JF Jernigan, JG AF Liu, MC Graham, JR Ghez, AM Meixner, M Arens, JF Jernigan, JG TI Mid-infrared imaging of young stellar objects SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, visual; circumstellar matter; infrared, stars; stars, imaging; stars, pre-main-sequence ID T-TAURI STARS; HIGH-SPATIAL-RESOLUTION; MAIN-SEQUENCE STARS; ORION POPULATION; L1551 IRS-5; MU-M; UNSEEN COMPANIONS; EXCITING SOURCES; ACCRETION DISKS; HL TAURI AB We present arcsecond resolution mid-infrared (8-13 mu m) images and photometry of four young stellar objects (YSOs)-L1551-IRS 5, HL Tau, AS 205, and AS 209 (V1121 Oph)-taken with the Berkeley Mid-Infrared Camera. For AS 205, a known T Tauri binary, we also present near-infrared JHK images and HKL' speckle imaging data. All three single stars are unresolved in our mid-IR images, consistent with current models of the circumstellar material associated with these objects. Our data are the first to resolve in the mid-IR both components of the close binary AS 205 (projected separation similar to 1 ''.3 [210 AU]). Both stars are classical T Tauri stars and possess the 9.7 mu m silicate feature in emission. AS 205 North is the IR brighter star in our data, while published observations find it to be the optically fainter star. Assuming that the IR excesses of both components arise from circumstellar disks, we find the emitting regions (the inner few AU) of the disks to be optically thick in the mid-IR. Pre-main-sequence evolutionary models suggest that the AS 205 system is non-coeval; we discuss possible explanations for this result and comment on the evolutionary status of this young binary. All our objects, except perhaps AS 205 South, exhibit changes in their mid-IR flux in measurements separated by intervals of days up to many years; the variations range from 30%-300%. For the classical T Tauri stars AS 205 North and AS 209, the magnitude of the changes seems to discount the possibility that the mid-IR variations have the same origin as the optical and near-IR variability of T Tauri stars, namely, accretion-related features on or near the stellar photosphere. We speculate that the cause of the variability lies in the accretion disks of these objects; the data suggest disk accretion rate fluctuations of nearly an order of magnitude. The existence of large mid-IR variability argues that simultaneous multiwavelength observations are needed for a proper analysis of YSO spectral energy distributions. C1 UNIV CALIF LOS ANGELES, DEPT ASTRON, LOS ANGELES, CA 90024 USA. UNIV ILLINOIS, DEPT ASTRON, URBANA, IL 61801 USA. LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94551 USA. UNIV CALIF BERKELEY, SPACE SCI LAB, BERKELEY, CA 94720 USA. RP Liu, MC (reprint author), UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. NR 90 TC 29 Z9 29 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1996 VL 461 IS 1 BP 334 EP 344 DI 10.1086/177060 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UD646 UT WOS:A1996UD64600027 ER PT J AU Shlosman, I Vitello, P Mauche, CW AF Shlosman, I Vitello, P Mauche, CW TI Rotating winds from accretion disks in cataclysmic variables: Eclipse modeling of V347 puppis SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, eclipsing; line, profiles; novae, cataclysmic variables; stars, individual (V347 Puppis); ultraviolet, stars ID UX-URSAE-MAJORIS; UV SPECTROSCOPY; Z CHAMAELEONTIS; STELLAR WINDS; SUPEROUTBURST; BINARIES; EMISSION; SPECTRA; SYSTEMS; FLOWS AB We study the eclipsing nova-like variable V347 Pup by matching its UV emission-line profiles in and out of eclipse to synthetic lines using a three dimensional kinematic and radiation transfer model. Our results support the accretion disk origin of winds in nonmagnetic cataclysmic variables as opposed to the white dwarf origin. Our main point concerns the importance of rotation for the UV emission-line shapes in such systems. In particular, we show that the narrowing of the UV emission lines in V347 Pup during eclipse can be easily explained by the eclipse of the innermost part of the wind by the secondary and the resulting reduction in the contribution of rotational broadening to the width of the lines. During the eclipse, the residual line flux is very sensitive to the maximum temperature of disk radiation. Good fits for reasonable mass-loss rates have been obtained for maximum disk temperatures approximate to 50,000 K. This constraint was imposed either by leveling off the inner disk temperature profiles, in agreement with recent observations of some nova-like objects, or by assuming that the accretion disk does not extend to the surface of the white dwarf, in which case V347 Pup would be an intermediate polar. In anticipation of high-speed spectrophotometry of cataclysmic variables by the Hubble Space Telescope, we provide a numerical model of a time-resolved eclipse of V347 Pup or similar such system to be verified by future observations. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Shlosman, I (reprint author), UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506, USA. NR 43 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1996 VL 461 IS 1 BP 377 EP 385 DI 10.1086/177066 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UD646 UT WOS:A1996UD64600033 ER PT J AU Libertin, CR LingIndeck, L Weaver, P ChangLiu, CM Strezoska, V Heckert, B Woloschak, GE AF Libertin, CR LingIndeck, L Weaver, P ChangLiu, CM Strezoska, V Heckert, B Woloschak, GE TI Dysregulation of temperature and liver cytokine gene expression in immunodeficient wasted mice SO CELLULAR IMMUNOLOGY LA English DT Article ID PROGRAMMED CELL-DEATH; C-FOS; ATAXIA TELANGIECTASIA; INTERLEUKIN-6; APOPTOSIS; PHASE; ABNORMALITIES; MECHANISMS; RADIATION; BIOLOGY AB Wasted mice bear the spontaneous autosomal recessive mutation wst/wst; this genotype is associated with weight loss beginning at 21 days of age, neurologic dysfunction, immunodeficiency at mucosal sites, and increased sensitivity to the killing effects of ionizing radiation. The pathology underlying the disease symptoms is unknown. Experiments reported here were designed to examine thermoregulation and liver expression of specific cytokines in wasted mice and in littermate and parental controls. Our experiments found that wasted mice begin to show a drop in body temperature at 21-23 days following birth, continuing until death at the age of 28 days. Concomitant with that, livers from wasted mice expressed increased amounts of mRNAs specific for cytokines IL-6 and IL-1, the acute phase reactant C-reactive protein, c-jun, and apoptosis-associated Rp-8 when compared to littermate and parental control animals. Levels of beta-transforming growth factor, c-fos, proliferating cell nuclear antigen, and ornithine amino transferase transcripts were the same in livers from wasted mice and controls. These results suggest a relationship between an acute phase reactant response in wasted mice and temperature dysregulation. (C) 1996 Academic Press, Inc. C1 LOYOLA UNIV, MED CTR, DEPT PATHOL, MAYWOOD, IL 60153 USA. LOYOLA UNIV, MED CTR, DEPT MED, MAYWOOD, IL 60153 USA. ARGONNE NATL LAB, CTR MECHANIST BIOL & BIOTECHNOL, ARGONNE, IL 60439 USA. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 NR 26 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0008-8749 J9 CELL IMMUNOL JI Cell. Immunol. PD APR 10 PY 1996 VL 169 IS 1 BP 62 EP 66 DI 10.1006/cimm.1996.0091 PG 5 WC Cell Biology; Immunology SC Cell Biology; Immunology GA UF065 UT WOS:A1996UF06500009 PM 8612295 ER PT J AU Bakac, A Won, TJ Espenson, JH AF Bakac, A Won, TJ Espenson, JH TI Novel pathways in the reactions of superoxometal complexes SO INORGANIC CHEMISTRY LA English DT Article ID MACROCYCLIC COBALT(II) COMPLEX; HYDROPEROXOCHROMIUM(III) ION; AQUEOUS-SOLUTION; OXYGEN-BINDING; KINETICS; CHROMIUM(II); RADICALS; THERMODYNAMICS; PORPHYRINS; REDUCTION AB The reaction of a 1:1 mixture of (H2O)(5)Cr(O-16(2))(2+) and (H2O)(5)Cr(O-18(2))(2+) at pH 1 did not yield measurable amounts of (OO)-O-16-O-18. This result rules out a Russell-type mechanism (2(H2O)(5)CrO22+ --> 2(H2O)(5)CrO2+ + O-2) for the bimolecular decomposition reaction. Evidence is presented in support of unimolecular (S(H)1) and bimolecular (S(H)2) homolyses as initial steps in the decomposition of (H2O)(5)CrO22+ in strongly acidic solutions (pH less than or equal to 1). In the pH range 4-5, (H2O)(5)CrO22+ undergoes hydrolysis-induced disproportionation to (H2O)(5)CrO2H2+, Cr(H2O)6(3+) and O-2. The first step produces HO2./O-2(.-) which in further reaction with (H2O)(5)CrO2+ yields the observed products. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP Bakac, A (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 37 TC 15 Z9 15 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 10 PY 1996 VL 35 IS 8 BP 2171 EP 2175 DI 10.1021/ic951144v PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UE973 UT WOS:A1996UE97300005 ER PT J AU Dong, ZC Corbett, JD AF Dong, ZC Corbett, JD TI CsTl: A new example of tetragonally compressed Tl-6(6-) octahedra. Electronic effects and packing requirements in the diverse structures of ATl (A=Li, Na, K, Cs) SO INORGANIC CHEMISTRY LA English DT Article ID ZINTL; PHASE AB The cesium-richest phase in the Cs-Tl system, CsTl, can be isolated as a pure crystalline phase through slow cooling of cesium-richer compositions in Ta followed by vacuum sublimation of the excess Cs at similar to 100 degrees C. The compound melts incongruently in the neighborhood of 150 degrees C. The structure was established by single crystal X-ray diffraction at room temperature (orthorhombic Fddd, Z = 48, a = 32.140(3) Angstrom, b = 15.136(1) Angstrom, and c = 9.2400(7) Angstrom. The isolated Tl-6(6-) ions in the structure, tetragonally compressed octahedra, exhibit D-2 symmetry with less than or equal to 0.063(4) Angstrom differences in edge lengths from D-4h. Extended Huckel calculations confirm the classical nature of the distortion in lowering the cluster electron count and charge. The diamagnetic CsTl differs from KTl, which contains more distorted Tl-6(6-) ions (C-2h), in a doubled a axis and an additional interpenetrating cluster anion sublattice. The smaller distortion of the clusters in CsTl originates with the lower field of the same number of cation neighbors in a more symmetric arrangement. The structural trend from LiTl (CsCl type) through the classic NaTl (stuffed diamond) to the related KTl and CsTl with compressed octahedra (and the absence of any such Rb phase) relates to the efficient packing of A(+) and (Tl-)(n) over a widely varying range of A(+) sizes, with only Na+ fitting well within a (3)(infinity)(Tl-) lattice. Similarly 4-bonded thallium in KTl and CsTl with somewhat shorter Tl-Tl distances is a necessary alternative when the infinite lattice cannot tolerate larger cations. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,US DOE,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 50 TC 43 Z9 43 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 10 PY 1996 VL 35 IS 8 BP 2301 EP 2306 DI 10.1021/ic951265v PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UE973 UT WOS:A1996UE97300024 ER PT J AU Rizzo, TG AF Rizzo, TG TI Like-sign charged Higgs boson production in e(+)e(-) collisions at the NLC SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS ID STANDARD-MODEL; TRIPLETS AB We consider the production of a pair of like-sign charged Higgs bosons in e(-)e(-) collisions at the NLC within the context of several electroweak models with extended symmetry breaking sectors. We find that the rate for this process, which proceeds through W-W- fusion, is a very sensitive probe of the nature of these extended Higgs sectors and that the corresponding cross sections can vary by as much as several orders of magnitude at NLC energies. RP Rizzo, TG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 9 TC 8 Z9 8 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1563 EP 1570 DI 10.1142/S0217751X96000742 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000006 ER PT J AU Barklow, TL AF Barklow, TL TI Electron compositeness limits in e(-)e(-) collisions SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS AB Electron compositeness limits from an e(-)e(-) collider are calculated and compared with the limits from an e(+)e(-) collider. We find that the e(-)e(-) collider gives significantly better limits than the e(+)e(-) collider for all center-of-mass energies if the e(-)e(-) and e(+)e(-) colliders have the same luminosity. RP Barklow, TL (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 2 TC 14 Z9 14 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1579 EP 1583 DI 10.1142/S0217751X96000766 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000008 ER PT J AU Rizzo, TG AF Rizzo, TG TI Extended gauge models and e(-)e(-)->W-W- at the NLC SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS ID RIGHT-HANDED CURRENTS; DECAY; COLLISIONS; BOSONS; SEARCH; MASS; E+E; WR AB We briefly discuss two possible manifestations of the lepton number violating reaction e(-)e(-) --> Wi-Wj(*)(-), which probes the masses and mixings of heavy Majorana neutrinos, at the Next Linear Collider(NLC). Cross sections fbr this process are shown to be potentially quite large at center of mass energies of order 1-1.5 TeV. RP Rizzo, TG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 26 TC 7 Z9 7 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1613 EP 1620 DI 10.1142/S0217751X96000808 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000012 ER PT J AU Markiewicz, TW AF Markiewicz, TW TI Experimentation at e(-)e(-) linear colliders SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS AB The design of the interaction region for an e(-)e(-) collider will involve an understanding of beam-beam effects, detector backgrounds, and the constraints required to maintain very small beam spot sizes. This paper reviews progress in the design of the e(+)e(-) interaction region of the proposed SLAG X-band NLC as a base design for the e(-)e(-) detector. RP Markiewicz, TW (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 12 TC 2 Z9 2 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1649 EP 1665 DI 10.1142/S0217751X96000857 PG 17 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000017 ER PT J AU Spencer, JE AF Spencer, JE TI Beam-beam effects and generalized luminosity SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS AB The assumption is made that before an NLC is approved, a prototype will be necessary that demonstrates the feasibility of a general purpose linear collider capable of (e) over right arrow(+/-)(e) over right arrow(+/-), <(gamma)over right arrow><(gamma)over right arrow>(+/-) and <(gamma)over right arrow><(gamma)over right arrow> incident channels. At an upgraded SLC, such channels could provide new physics over a range of energies upwards of a few GeV. Effects that limit the luminosity of a GLC are discussed together with their possible mitigations. The expected luminosities in the different channels are then predicted in a consistent way for root s(ee) = 0.5 TeV. RP Spencer, JE (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 9 TC 16 Z9 16 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1675 EP 1686 DI 10.1142/S0217751X96000870 PG 12 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000019 ER PT J AU Chen, P Spitkovsky, A Weidemann, AW AF Chen, P Spitkovsky, A Weidemann, AW TI Beam-beam disruption and the case for a plasma lens in e(-)e(-) collisions SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS AB After a short review of the expected beam-beam disruption effects in e(-)e(-) collisions we show estimates that a plasma lens will improve the luminosity for a SLC- and NLC-energy e(-)e(-) collider. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. RP Chen, P (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 10 TC 5 Z9 5 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1687 EP 1692 DI 10.1142/S0217751X96000882 PG 6 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000020 ER PT J AU Erickson, R AF Erickson, R TI Comments on the possible use of the SLC as an e(-)e(-) collider SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Electron-Electron Linear Collider Workshop (E E 1995) CY SEP 05-06, 1995 CL UNIV CALIF SANTA CRUZ COMPUS, SANTA CRUZ, CA SP Santa Cruz Inst Particle Phys HO UNIV CALIF SANTA CRUZ COMPUS AB In this letter, we discuss practical issues that must be addressed to reconfigure the SLAC Linear Collider as the first muiti-GeV e(-)e(-) collider. RP Erickson, R (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 1 TC 2 Z9 2 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 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD APR 10 PY 1996 VL 11 IS 9 BP 1693 EP 1697 DI 10.1142/S0217751X96000894 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UG050 UT WOS:A1996UG05000021 ER PT J AU Abney, M Epstein, RI AF Abney, M Epstein, RI TI Ekman pumping in compact astrophysical bodies SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SPIN-UP; STRATIFIED FLUID; CLOSE BINARIES; NEUTRON-STARS; SYNCHRONIZATION; CYLINDER; REST; GAS AB We examine the dynamics of a rotating viscous fluid following an abrupt change in the angular velocity of the solid bounding surface. We include the effects of a density stratification and compressibility which are important in astrophysical objects such as neutron stars. We confirm and extend the conclusions of previous studies that stratification restricts the Ekman pumping process to a relatively thin layer near the boundary, leaving much of the interior fluid unaffected. We find that finite compressibility further inhibits Ekman pumping by decreasing the extent of the pumped layer and by increasing the time for spin-up. The results of this paper are important for interpreting the spin period discontinuities ('glitches') observed in rotating neutron stars. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Abney, M (reprint author), UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,ENRICO FERMI INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 26 TC 21 Z9 21 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 APR 10 PY 1996 VL 312 BP 327 EP 340 DI 10.1017/S0022112096002030 PG 14 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA UH147 UT WOS:A1996UH14700014 ER PT J AU Fleck, RJ Turrin, BD Sawyer, DA Warren, RG Champion, DE Hudson, MR Minor, SA AF Fleck, RJ Turrin, BD Sawyer, DA Warren, RG Champion, DE Hudson, MR Minor, SA TI Age and character of basaltic rocks of the Yucca Mountain region, southern Nevada SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID WELLS-VOLCANIC-CENTER; WESTERN UNITED-STATES; LATHROP-WELLS; ISOTOPIC EVIDENCE; CENOZOIC BASALTS; WASTE REPOSITORY; GREAT-BASIN; GEOCHRONOLOGY; SITE; GEOCHEMISTRY AB Volcanism in the Yucca Mountain region of southern Nevada in the last 5 m.y. is restricted to moderate-to-small volumes of subalkaline basaltic magmas, produced during at least 6 intervals, and spanning an age range from 4.6 Ma to about 125 ka. Where paleomagnetic evidence is available, the period of volcanism at individual eruptive centers apparently was geologically short-lived, even where multiple eruptions involved different magma types. K-Ar studies are consistent with most other geochronologic information, such as the minimum ages of exposure-dating techniques, and show no evidence of renewed volcanism after a significant quiescence at any of the centers in the Yucca Mountain region. A volcanic recurrence interval of 860 +/- 350 kyr is computed from a large K-Ar data set and an evaluation of their uncertainties. Monte Carlo error propagations demonstrate the validity of uncertainties obtained for weighted-mean ages when modified using the goodness of fit parameter, MSWD. Elevated Sr-87/Sr-86 initial ratios (Sr-i) in the basalts, nearly constant at 0.707, combined with low SiO2 and Rb/Sr ratios indicate a subcontinental, lithospheric mantle source, previously enriched in radiogenic Sr and depleted in Rb. Beginning with eruptions of the most voluminous eruptive center, the newly dated Pliocene Thirsty Mountain volcano, basaltic magmas have decreased in eruptive volume, plagioclase-phenocryst content, various trace element ratios, and TiO2, while increasing in light rare earth elements, U, Th, P2O5, and Light REE/heavy REE ratios. These time-correlated changes are consistent with either increasing depths of melting or a decreasing thermal gradient in the Yucca Mountain region during the last 5 ray. C1 US GEOL SURVEY, DENVER, CO 80225 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RP Fleck, RJ (reprint author), US GEOL SURVEY, 345 MIDDLEFIELD RD, MS 937, MENLO PK, CA 94025 USA. NR 84 TC 27 Z9 27 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1996 VL 101 IS B4 BP 8205 EP 8227 DI 10.1029/95JB03123 PG 23 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA UF005 UT WOS:A1996UF00500014 ER PT J AU Lindquist, WB Lee, SM Coker, DA Jones, KW Spanne, P AF Lindquist, WB Lee, SM Coker, DA Jones, KW Spanne, P TI Medial axis analysis of void structure in three-dimensional tomographic images of porous media SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID 2-PHASE RANDOM-MEDIA; PORE-SIZE DISTRIBUTION; X-RAY; SYNCHROTRON RADIATION; PROBABILITY FUNCTIONS; MICROTOMOGRAPHY; MICROSTRUCTURE; PERMEABILITY; RECONSTRUCTION; DIFFUSION AB We introduce the medial axis as a tool in the analysis of geometric structure of void space in porous media, The medial axis traces the fundamental geometry of the void pathways. We describe an algorithm for generating the medial axis of the void structure from digitized three dimensional images of porous media obtained from X ray CAT scans. The medial axis is constructed during an iterative erosion procedure which, at each step, replaces the image of the void structure with a smaller version obtained by eroding its surface layer of voxels. The algorithm is applied to high (5 mu m) resolution microtomographic images of two rock chips (Berea sandstone and Danish chalk) and a sample pf uniform (100 mu m) diameter, packed glass beads. We statistically investigate several geometrical properties of the structure bf the medial axes obtained. The first is the distribution of relative volumes in each erosion layer of the void space. We find the distributions to be exponential for the two real rock samples and normal for the packed glass beads. The second property investigated is the distribution of volumes of disconnected segments of the medial axis which are in one-to-one correspondence with disconnected void segments of the sample. We find indications for a; universal power law behavior governing the distribution of volumes of the smallest disconnected pieces. The final behavior studied is a geometric tortuosity as measured by shortest paths through the medial axis. This tortuosity distribution appears well described by a gamma distribution. C1 SUNY COLL TECHNOL UTICA, INST TECHNOL, MATH & SCI DEPT, UTICA, NY USA. BROOKHAVEN NATL LAB, DEPT APPL SCI, UPTON, NY 11973 USA. RP Lindquist, WB (reprint author), SUNY STONY BROOK, DEPT APPL MATH & STAT, STONY BROOK, NY 11974 USA. NR 42 TC 204 Z9 208 U1 2 U2 33 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 1996 VL 101 IS B4 BP 8297 EP 8310 DI 10.1029/95JB03039 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA UF005 UT WOS:A1996UF00500019 ER PT J AU Appelman, EH Jache, AW Muntean, JV AF Appelman, EH Jache, AW Muntean, JV TI The vanadium(V)-catalyzed oxidation of (1-hydroxyethylidene)bisphosphonic acid, CH3C(OH)(PO3H2)(2), by hydrogen peroxide in aqueous solution SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE phosphonic acid; hydrogen peroxide; vanadium; oxidation ID METAL CATALYSIS; COMPLEXES; HYDROXYLATION; STABILITY; RESONANCE; ALCOHOLS; VANADIUM AB The vanadium(V)-catalyzed oxidation of (I-hydroxyethylidene)bisphosphonic acid, CH3C(OH)(PO3H2)(2), by hydrogen peroxide in aqueous solution has been studied at temperatures between 50 and 80 degrees C. In contrast to vanadium(V), six-valent Mo and W are without significant catalytic action, as is SeO2, while OsO4 is only weakly catalytic. With excess substrate a limiting stoichiometry is reached in which ca. 4 mol H2O2 are consumed per mol of substrate oxidized. With excess H2O2, the reaction competes with catalytic decomposition of the peroxide, and a substantial excess of peroxide is required to consume the substrate completely. The reaction is optimal near pH 1. At higher pH it becomes slower, while at lower pH the catalytic decomposition of H2O2 comes to predominate. The principal reaction products are phosphoric and acetic acids and carbon dioxide, along with lesser quantities of CO and formic acid. The consumption of substrate in the presence of a large excess of H2O2 follows first-order kinetics, but the apparent first-order rate constant shows a weak positive dependence on initial substrate concentration, which may be pH-related, and at high substrate concentration it shows a weak negative dependence on initial [H2O2]. The principal reactant appears to be the diperoxovanadium(V) anion, OV(O-2)(2)(-), but the apparent rate shows a greater-than-first-order dependence on catalyst concentration, suggesting a secondary reaction path involving a dimeric peroxovanadium species. A free-radical mechanism has been proposed in which one-electron reduction of the vanadium accompanies oxidation of the substrate to an intermediate alkoxyl radical species that can yield either acetic acid or CO2. This mechanism is supported by the observation that vanadium(V) itself oxidizes the substrates at a measurable rate. RP Appelman, EH (reprint author), ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. NR 31 TC 5 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD APR 10 PY 1996 VL 106 IS 3 BP 197 EP 209 DI 10.1016/1381-1169(95)00288-X PG 13 WC Chemistry, Physical SC Chemistry GA UE531 UT WOS:A1996UE53100003 ER PT J AU Su, K Tilley, TD Sailor, MJ AF Su, K Tilley, TD Sailor, MJ TI Molecular and polymer precursor routes to manganese-doped zinc orthosilicate phosphors SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID AMORPHOUS OXIDE; POLYMETALLOXANES; CERAMICS; COMPLEXES; CATALYSTS; ALKOXIDES AB The zinc alkoxy(siloxy) complex {Zn[OSi(O(t)Bu)(3)](2)}(2) has been prepared and studied as a molecular precursor to zinc orthosilicate, Zn2SiO4. This complex, prepared by reaction of ZnMe(2) with HOSi(O(t)Bu)(3), has been characterized by X-ray crystallography as a dimer with two four-coordinate zinc centers. It cleanly looses isobutene, tert-butyl alcohol, and HOSi(O(t)Bu)(3) at ca. 100 degrees C to produce Zn2SiO4 . SiO2. Reaction of ZnMe(2) with (HO)(2)Si(O(t)Bu)(2) affords the hydrocarbon-soluble polymer [ZnOSi(O(t)Bu)(2)O](n), which is proposed to have a structure consisting of four-coordinate Zn atoms linked by bridging -O((t)BuO)Si(O(t)Bu)O- groups. This polymer undergoes a very clean ceramic conversion over 150-250 degrees C to give the theoretical yield of carbon-free (by infrared spectroscopy and combustion analyses) Zn2SiO4 . SiO2. The pyrolytic elimination products consist of water, tert-butyl alcohol, and isobutene. X-ray diffraction studies on the ceramic products show that Zn2SiO4 is the only zinc-containing, crystalline product formed. Thus this precursor approach appears to offer an advantage over sol-gel processes, which tend to produce ZnO as a side product. Hydrocarbon solutions of the polymer were used to fabricate high-quality thin films. Via pyrolysis of [ZnOSi(O(t)Bu)(2)O](n)/[Mn(CH(2)SiMe(3))(2)](m) mixtures, manganese-doped Zn2SiO4 . SiO2 materials were synthesized. These materials exhibit two photoluminescence emission bands centered at 535 (major) and 605 nm (minor). The intensity of the green emission at 535 nm, which is responsible for the cathodoluminescence properties of Zn2SiO4:Mn phosphors, is highly dependent on the level of manganese doping. Concentration quenching is observed at higher manganese contents. The observed photoluminescence decay lifetime of approximately 5 ms is typical for Zn2SiO4:Mn phosphors. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. UNIV CALIF SAN DIEGO,DEPT CHEM & BIOCHEM,LA JOLLA,CA 92093. NR 57 TC 102 Z9 104 U1 2 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 10 PY 1996 VL 118 IS 14 BP 3459 EP 3468 DI 10.1021/ja9537639 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA UE656 UT WOS:A1996UE65600018 ER PT J AU Schirber, JE Hansen, L Morosin, B Fischer, JE Jorgensen, JD Kwei, GH AF Schirber, JE Hansen, L Morosin, B Fischer, JE Jorgensen, JD Kwei, GH TI Effect of pressure on the superconducting primitive cubic and ''polymeric'' phases of Na2CsC60 SO PHYSICA C LA English DT Article ID TRANSITION-TEMPERATURE; DEPENDENCE; C-60 AB The pressure dependence of the superconducting transition temperature, T-c, has been determined using several gaseous pressure media and a variety of pressure-temperature cycles, both of which profoundly affect T-c. The orthorhombic ''polymer'' phase discussed by Zhu is found to be superconducting. Models for the unexpected behavior are discussed. C1 UNIV PENN,PHILADELPHIA,PA 19104. ARGONNE NATL LAB,ARGONNE,IL 60439. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Schirber, JE (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 17 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 10 PY 1996 VL 260 IS 3-4 BP 173 EP 176 DI 10.1016/0921-4534(96)00145-1 PG 4 WC Physics, Applied SC Physics GA UJ484 UT WOS:A1996UJ48400002 ER PT J AU SadeMelo, CAR AF SadeMelo, CAR TI Paramagnetism and reentrant behavior in quasi-one-dimensional superconductors at high magnetic fields SO PHYSICA C LA English DT Article AB The thermodynamics of quasi-one-dimensional superconductors in the presence of large magnetic fields is studied. When the quantum effects of the magnetic field are taken into account, several reentrant superconducting phases persist at very high fields. In the last reentrant phase the free-energy change, the specific-heat jump and the excess magnetization are estimated near the critical temperature. In particular, the excess magnetization is found to be paramagnetic as opposed to diamagnetic in weak fields and its sign is controlled by the slope of H-c2(T). We further generalize this result to the entire phase diagram (including all quantum phases) and to different physical systems using general thermodynamic relations which show that the sign of the excess magnetization Delta M of the superconducting state near H-c2(T) follows dH(c2)(T)/dT. These relations provide a scenario for the evolution of the sign of Delta M from weak fields to strong fields. RP SadeMelo, CAR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 20 Z9 20 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 10 PY 1996 VL 260 IS 3-4 BP 224 EP 230 PG 7 WC Physics, Applied SC Physics GA UJ484 UT WOS:A1996UJ48400008 ER PT J AU Selvamanickam, V Finkle, T Pfaffenbach, K Haldar, P Peterson, EJ Salazaar, KV Roth, EP Tkaczyk, JE AF Selvamanickam, V Finkle, T Pfaffenbach, K Haldar, P Peterson, EJ Salazaar, KV Roth, EP Tkaczyk, JE TI Processing of thallium-based superconducting tapes for high current density SO PHYSICA C LA English DT Article ID TL AB Optimum thermomechanical processing conditions have been developed to achieve a high current density in powder-in-tube (PIT) thallium-based (Tl,Pb)-1223 and (Tl,Bi)-1223 tapes. Critical currents in excess of 25 A corresponding to a current density of 20000 A/cm(2) have been achieved in these tapes at 77 K. Heat treatment and intermediate deformation sequences, heating rates, and starting precursor phase assemblages have been examined to optimize the current density. A combination of processing conditions that result in incremental densification, less microcracking and liquid formation in the early and final stages of thermomechanical treatment is found to result in the highest current densities. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. GE CO,SCHENECTADY,NY 12301. RP Selvamanickam, V (reprint author), INTERMAGNET GEN CORP,LATHAM,NY 12110, USA. NR 10 TC 26 Z9 26 U1 1 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 APR 10 PY 1996 VL 260 IS 3-4 BP 313 EP 320 DI 10.1016/0921-4534(96)00143-8 PG 8 WC Physics, Applied SC Physics GA UJ484 UT WOS:A1996UJ48400018 ER PT J AU Shek, ML AF Shek, ML TI Soft X-ray studies of a c(4x2)(*) beta-SiC(100) surface SO SURFACE SCIENCE LA English DT Article DE low energy electron diffraction; semiconducting surfaces; silicon carbide; soft X-ray photoelectron spectroscopy; stepped single crystal surfaces; surface electronic phenomena ID SCANNING TUNNELING MICROSCOPY; SI(100) SURFACES; SILICON-CARBIDE; ELECTRONIC-STRUCTURES; SI; PHOTOEMISSION; SI(001); GROWTH; 2X1; RECONSTRUCTION AB We report soft X-ray results for a Si-terminated beta-SiC(100) surface characterized by a c(4 x 2) plus a weak possibly (2 x 2) reconstruction in low-energy-electron diffraction. The existence of two surface Si 2p photoemission core levels is confirmed, shifted by -0.5 and -1.4 eV from the bulk-like level. We further show results which indicate that the component with the large -1.4 eV shift is correlated with the surface reconstruction. Surface-sensitive Si L(23) absorption spectra suggest the existence of a high density of unfilled s-like states about 1.3 eV above, as well as unfilled s-like states near, the bulk conduction band minimum. Reconstructed surfaces beyond this ''c(4 x 2)*'' surface are also noted. RP Shek, ML (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973, USA. NR 40 TC 54 Z9 54 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 10 PY 1996 VL 349 IS 3 BP 317 EP 332 DI 10.1016/0039-6028(95)01047-5 PG 16 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA UF921 UT WOS:A1996UF92100015 ER PT J AU Borgstahl, GEO Parge, HE Hickey, MJ Johnson, MJ Boissinot, M Hallewell, RA Lepock, JR Cabelli, DE Tainer, JA AF Borgstahl, GEO Parge, HE Hickey, MJ Johnson, MJ Boissinot, M Hallewell, RA Lepock, JR Cabelli, DE Tainer, JA TI Human mitochondrial manganese superoxide dismutase polymorphic variant Ile58Thr reduces activity by destabilizing the tetrameric interface SO BIOCHEMISTRY LA English DT Article ID DIFFERENTIAL SCANNING CALORIMETRY; TUMOR NECROSIS FACTOR; PROTEIN-STRUCTURE; PULSE-RADIOLYSIS; FREE-RADICALS; O2 RADICALS; EXPRESSION; INDUCTION; MELANOMA; ENZYME AB Human manganese superoxide dismutase (MnSOD) is a homotetrameric enzyme which protects mitochondria against oxygen-mediated free radical damage. Within each subunit, both the N-terminal helical hairpin and C-terminal alpha/beta domains contribute ligands to the catalytic manganese site. Two identical four-helix bundles, symmetrically assembled from the N-terminal helical hairpins, form a novel tetrameric interface that stabilizes the active sites. The 2.5 Angstrom crystallographic structure of the naturally occurring polymorphic variant Ile58Thr MnSOD reveals that the helical hairpin mutation Thr58 causes two packing defects in each of the two four-helix bundles of the tetrameric interface. Similar mutations, expected to cause packing defects in the Cu,ZnSOD dimer interface, are associated with the degenerative disease amyotrophic lateral sclerosis. Ile58Thr MnSOD is primarily dimeric in solution and is significantly less thermostable than the normal enzyme, with decreases of 15 degrees C in the main melting temperature and 20 degrees C in the heat-inactivation temperature. Consequently, this mutant MnSOD is compromised at normal body temperatures: thermal inactivation, predicted from the decrease in thermal stability, occurs with a theoretical half-life of only 3.2 h at 37 degrees C (1.4 h at 41 degrees C), compared with 3.1 years for native MnSOD. This prediction is supported by direct measurements: incubation at 41.7 degrees C for 3 h has no effect on the activity of native MnSOD but completely inactivates mutant MnSOD. Rapid inactivation of Ile58Thr MnSOD at the elevated temperatures associated with fever and inflammation could provide an early advantage by killing infected cells, but also would increase superoxide-mediated oxidative damage and perhaps contribute to late-onset diseases. C1 SCRIPPS RES INST, DEPT MOLEC BIOL, LA JOLLA, CA 92037 USA. UNIV LONDON IMPERIAL COLL SCI & TECHNOL, DEPT BIOCHEM, LONDON SW7 2AZ, ENGLAND. UNIV WATERLOO, DEPT PHYS, WATERLOO, ON N2L 3G1, CANADA. BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. FU NIGMS NIH HHS [GM48495, GM23658]; Wellcome Trust NR 62 TC 117 Z9 118 U1 1 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 9 PY 1996 VL 35 IS 14 BP 4287 EP 4297 DI 10.1021/bi951892w PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UE612 UT WOS:A1996UE61200005 PM 8605177 ER PT J AU Sutherland, DGJ Carlisle, JA Elliker, P Fox, G Hagler, TW Jimenez, I Lee, HW Pakbaz, K Terminello, LJ Williams, SC Himpsel, FJ Shuh, DK Tong, WM Jia, JJ Callcott, TA Ederer, DL AF Sutherland, DGJ Carlisle, JA Elliker, P Fox, G Hagler, TW Jimenez, I Lee, HW Pakbaz, K Terminello, LJ Williams, SC Himpsel, FJ Shuh, DK Tong, WM Jia, JJ Callcott, TA Ederer, DL TI Photo-oxidation of electroluminescent polymers studied by core-level photoabsorption spectroscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID LIGHT-EMITTING-DIODES AB The C 1s and O 1s core-level photoabsorption spectra of poly[2-methoxy,5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene] (MEH-PPV) before and after exposure O-2 and broadband visible light were recorded to determine the degradation pathway for this polymer. The change in the O 1s spectra as a function of exposure demonstrates that the O adds to the polymer chain to form a carbonyl group. Exposure to only O-2 or only light causes no change in the C 1s or O 1s spectra. In the C 1s spectra, the change in the dependence on the photon angle of incidence after exposure demonstrates that O attacks the polymer at the double bond in the vinyl group thereby altering the extended conjugation of the polymer. (C) 1996 American Institute of Physics. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. RP Sutherland, DGJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Jimenez, Ignacio/F-7422-2010; Tong, William/D-2564-2010 OI Jimenez, Ignacio/0000-0001-5605-3185; NR 11 TC 93 Z9 95 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 8 PY 1996 VL 68 IS 15 BP 2046 EP 2048 DI 10.1063/1.116298 PG 3 WC Physics, Applied SC Physics GA UD974 UT WOS:A1996UD97400005 ER PT J AU Lee, JW Pearton, SJ Zolper, JC Stall, RA AF Lee, JW Pearton, SJ Zolper, JC Stall, RA TI Hydrogen passivation of Ca acceptors in GaN SO APPLIED PHYSICS LETTERS LA English DT Article ID GALLIUM NITRIDE; DEVICES AB Exposure to a hydrogen plasma at 250 degrees C of p-type GaN (Ca) prepared by either Ca+ or Ca+ plus P+ co-implantation leads to a reduction in sheet carrier density of approximately an order of magnitude (1.6X10(12) cm(-2) to 1.8X10(11) cm(-2)), and an accompanying increase in hole mobility (6 cm(2)/V s to 18 cm(2)/V s). The passivation process can be reversed by posthydrogenation annealing at 400-500 degrees C under a N-2 ambient. This reactivation of the accepters is characteristic of the formation of neutral (Ca-H) complexes in the GaN. The thermal stability of the passivation is similar to that of Mg-H complexes in material prepared in the same manner (implantation) with similar initial doping levels. Hydrogen passivation of acceptor dopants in GaN appears to be a ubiquitous phenomenon, as it is in other p-type semiconductors. (C) 1996 American Institute of Physics. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. EMCORE CORP,SOMERSET,NJ 08873. RP Lee, JW (reprint author), UNIV FLORIDA,GAINESVILLE,FL 32611, USA. NR 19 TC 38 Z9 38 U1 4 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 8 PY 1996 VL 68 IS 15 BP 2102 EP 2104 DI 10.1063/1.115598 PG 3 WC Physics, Applied SC Physics GA UD974 UT WOS:A1996UD97400024 ER PT J AU Vanheusden, K Warren, WL Schwank, JR Fleetwood, DM Shaneyfelt, MR Winokur, PS Devine, RAB AF Vanheusden, K Warren, WL Schwank, JR Fleetwood, DM Shaneyfelt, MR Winokur, PS Devine, RAB TI Nonuniform oxide charge and paramagnetic interface traps in high-temperature annealed Si/SiO2/Si structures SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRON-SPIN-RESONANCE; BURIED OXIDES; SI-SIO2 INTERFACE; 100 SILICON; PB DEFECTS; CENTERS; GENERATION; HYDROGEN; STATES; SIMOX AB Trivalent silicon P-b0 and P-b1 defects were identified at both the top Si(100)/buried-SiO2 and buried-SiO2/bottom-Si(100) interfaces in high-temperature (1320 degrees C) annealed Si/SiO2/Si structures. The paramagnetic defects are generated by annealing in a flow of pure nitrogen (N-2) or forming gas [N2H2; 95:5 (by volume)] at 550 degrees C. In addition, the forming-gas anneal also generated positive charge in the buried oxides; significant lateral nonuniformities in the buried oxide charge density were observed following this anneal. These macroscopic inhomogeneities may be linked to previous reports of homogeneity related problems involving the SIMOX buried oxide, such as early breakdown and etch pits, suggesting that these types of measurements may be useful as nondestructive screens of SIMOX wafer quality. (C) 1996 American Institute of Physics. C1 FRANCE TELECOM,CTR NATL ETUD TELECOMMUN,F-38243 MEYLAN,FRANCE. RP Vanheusden, K (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 23 TC 15 Z9 15 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 8 PY 1996 VL 68 IS 15 BP 2117 EP 2119 DI 10.1063/1.115603 PG 3 WC Physics, Applied SC Physics GA UD974 UT WOS:A1996UD97400029 ER PT J AU Hahn, DW Edwards, CF McCarty, KF Kee, RJ AF Hahn, DW Edwards, CF McCarty, KF Kee, RJ TI Large-area diamond deposition in an atmospheric pressure stagnation-flow reactor SO APPLIED PHYSICS LETTERS LA English DT Article ID FLAT FLAME AB We present the results of large-area (20 cm(2)) diamond deposition from a scaled-up stagnation-flow reactor. The reactor uses a unique nozzle geometry that optimizes reagent gas usage. The premixed acetylene-oxygen-hydrogen flames were operated in a highly strained configuration, allowing uniform deposition of diamond with growth rates exceeding 25 mu m/h. Substrate temperature control and flame stability of the chemical vapor deposition reactor are described. Diamond films were deposited on a molybdenum substrate with a surface temperature of approximately 1200 K and C/O ratio of 1.03. Diamond film growth results are presented, and film uniformity is assessed using micro-Raman spectroscopy. (C) 1996 American Institute of Physics. RP Hahn, DW (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94551, USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 13 TC 12 Z9 12 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 8 PY 1996 VL 68 IS 15 BP 2158 EP 2160 DI 10.1063/1.116014 PG 3 WC Physics, Applied SC Physics GA UD974 UT WOS:A1996UD97400043 ER PT J AU Marathe, MV Ravi, SS AF Marathe, MV Ravi, SS TI On approximation algorithms for the minimum satisfiability problem SO INFORMATION PROCESSING LETTERS LA English DT Article DE analysis of algorithms; computational complexity AB We consider the following minimum satisfiability (MINSAT) problem: Given a CNF formula, find a truth assignment to the variables that minimizes the number of satisfied clauses, This problem was shown to be NP-complete by R. Kohli, R. Krishnamurti and P. Mirchandani (1994). They also presented an approximation algorithm whose performance guarantee is equal to the maximum number of literals in a clause, We present an approximation-preserving reduction from MINSAT to the minimum vertex cover (MINVC) problem. This reduction, in conjunction with known heuristics for the MINVC problem, yields a heuristic with a performance guarantee of 2 for MINSAT. Further, we show that if there is an approximation algorithm with a performance guarantee rho for MINSAT, then there is an approximation algorithm with the same performance guarantee rho for the minimum vertex cover problem. This result points out the difficulty of devising an approximation algorithm with a performance guarantee better than 2 for MINSAT. We also observe that MINSAT remains NP-complete even when restricted to planar instances. C1 SUNY ALBANY, DEPT COMP SCI, ALBANY, NY 12222 USA. RP LOS ALAMOS NATL LAB, POB 1663, MS M986, LOS ALAMOS, NM 87545 USA. NR 24 TC 21 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0020-0190 EI 1872-6119 J9 INFORM PROCESS LETT JI Inf. Process. Lett. PD APR 8 PY 1996 VL 58 IS 1 BP 23 EP 29 DI 10.1016/0020-0190(96)00031-2 PG 7 WC Computer Science, Information Systems SC Computer Science GA UP891 UT WOS:A1996UP89100005 ER PT J AU Franceschetti, A Zunger, A AF Franceschetti, A Zunger, A TI GaAs quantum structures: Comparison between direct pseudopotential and single-band truncated-crystal calculations SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BINDING CLUSTER MODEL; SEMICONDUCTOR CLUSTERS; ELECTRONIC-PROPERTIES; SI; FILMS; GE AB single-band approach for semiconductor clusters which accounts for the nonparabolicity of the energy bands was recently used by Rama Krishna and Friesner [M.V. Rama Krishna and R.A. Friesner, Phys. Rev. Lett. 67, 629 (1991)]. We compare the results of this method (denoted here as single-band truncated-crystal, or SBTC, approximation) with a direct pseudopotential band-structure calculation for free-standing hydrogen-passivated GaAs quantum films, wires, and dots. The direct pseudopotential calculation, which includes coupling between all bands, shows that isolated GaAs quantum films, wires, and dots have an indirect band gap for thicknesses below 16, 28, and at least 30 Angstrom (8, 14, and at least 15 ML), respectively; beyond these critical dimensions the transition becomes direct. A comparison of the SBTC approximation with the direct pseudopotential calculation shows that (i) the confinement energy of the valence-band maximum is overestimated by the SBTC method, because the zero-confinement character of this state is neglected; (ii) the confinement energy of the Gamma-derived conduction state (direct band gap) is slightly overestimated by the SBTC approximation, mainly because of the assumption of infinite potential barriers at the boundaries; (iii) the confinement energy of the X-derived conduction state (indirect band gap) is severely underestimated by the SBTC method; (iv) while the SBTC approximation predicts ''quantum deconfinement'' (i.e., reduction of gap as size is reduced) for the direct gap of thin GaAs quantum wires, such effect is not present in the direct pseudopotential calculation. (C) 1996 American Institute of Physics. RP Franceschetti, A (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Schaff, William/B-5839-2009; Zunger, Alex/A-6733-2013 NR 24 TC 22 Z9 22 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 8 PY 1996 VL 104 IS 14 BP 5572 EP 5578 DI 10.1063/1.471797 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD670 UT WOS:A1996UD67000024 ER PT J AU Tsunoda, Y Nicklow, RM AF Tsunoda, Y Nicklow, RM TI Spin-density waves in Cr under a magnetic field SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID POLARIZED NEUTRON; CHROMIUM; EXCITATIONS AB The twisting of the spin-density wave (SDW) in Cr in the transverse SDW phase has been examined by neutron scattering experiments in a magnetic field. Twisting beyond experimental errors was observed, but the twisting angle is very small compared to the rotation angle of the SDW in the magnetic field. This result is consistent with the fact that the transverse spin fluctuation in the Cr SDW is strongly suppressed at low excitation energies. The anisotropy energy of the SDW in Cr is also discussed. C1 OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. RP Tsunoda, Y (reprint author), WASEDA UNIV, SCH SCI & ENGN, SHINJUKU KU, 3-4-1 OKUBO, TOKYO 169, JAPAN. NR 16 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 8 PY 1996 VL 8 IS 15 BP 2655 EP 2662 DI 10.1088/0953-8984/8/15/014 PG 8 WC Physics, Condensed Matter SC Physics GA UG223 UT WOS:A1996UG22300014 ER PT J AU Kent, MS Factor, BJ Satija, S Gallagher, P Smith, GS AF Kent, MS Factor, BJ Satija, S Gallagher, P Smith, GS TI Structure of bimodal polymer brushes in a good solvent by neutron reflectivity SO MACROMOLECULES LA English DT Article ID GRAFTED CHAINS; KINETICS; FORCES AB Neutron reflection is used to examine the concentration profile of bimodal tethered layers in a good solvent. The tethered layers are Langmuir monolayers of highly asymmetric poly(dimethyl-siloxane)-polystyrene (PDMS-PS) diblock copolymers at the air surface of ethyl benzoate. The PS blocks dangle into the good solvent, while the PDMS blocks anchor the copolymers to the surface. Bimodal layers are prepared using two block copolymers which vary in the molecular weight of the dangling block. The presence of the smaller PS blocks (DOP = N-1) leads to additional stretching of the larger PS blocks (DOP = N-2) relative to their dimension in a single-component monolayer, while the dimension of the smaller PS blocks is largely unaffected by the presence of the larger blocks. For the three bimodal brushes examined; the effect of additional stretching for the larger chains is greatest (up to 30%) for N-2 congruent to 3N(1), smaller for N-2 congruent to 5N(1), and negligible for N-2 congruent to 11N(1). These trends are in agreement with self-consistent field calculations reported in the literature. In addition, it is observed that the chains with shorter dangling blocks add preferentially to an existing copolymer monolayer when the chains in the monolayer are strongly interacting. This is attributed to a greater potential barrier for the longer chains to incorporate into the monolayer due to osmotic and steric interactions. C1 NIST,GAITHERSBURG,MD 20899. LOS ALAMOS NATL LAB,LANCSE,LOS ALAMOS,NM 87545. RP Kent, MS (reprint author), SANDIA NATL LABS,DEPT 1815,ALBUQUERQUE,NM 87185, USA. NR 18 TC 37 Z9 37 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 8 PY 1996 VL 29 IS 8 BP 2843 EP 2849 DI 10.1021/ma951497d PG 7 WC Polymer Science SC Polymer Science GA UD693 UT WOS:A1996UD69300017 ER PT J AU Dorset, DL Annis, BK AF Dorset, DL Annis, BK TI Lamellar order and the crystallization of linear chain solid solutions SO MACROMOLECULES LA English DT Article ID CRYSTAL-STRUCTURE; POLYETHYLENE; PARAFFINS; POLYMERS; ALKANES AB Single crystals have been grown from binary n-paraffin solid solutions and from multicomponent waxes and low molecular weight polyethylenes. Although conformational and longitudinal disorder must affect the lamellar interface in multilamellar crystals, the interlamellar interaction still must remain regular enough to account for the observed long-range correlation, over large distances (e.g. 10 mu m), of successive stacked lamellae. Surface decoration experiments on mixed chain monolamellae with polymethylene fragments as well as atomic force microscopy verify this assertion that the lamellar surface is still flat and well-ordered. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. RP Dorset, DL (reprint author), HAUPTMAN WOODWARD MED RES INST INC,ELECTRON DIFFRACT DEPT,73 HIGH ST,BUFFALO,NY 14203, USA. NR 35 TC 21 Z9 21 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 8 PY 1996 VL 29 IS 8 BP 2969 EP 2973 DI 10.1021/ma9514277 PG 5 WC Polymer Science SC Polymer Science GA UD693 UT WOS:A1996UD69300033 ER PT J AU Horen, DJ Satchler, GR Fayans, SA Trykov, EL AF Horen, DJ Satchler, GR Fayans, SA Trykov, EL TI Microscopic description of the excitation of some states in the Zr-90,Zr-92,Zr-94,Zr-96 isotopes SO NUCLEAR PHYSICS A LA English DT Article ID TRANSITION CHARGE-DENSITIES; INELASTIC ALPHA-SCATTERING; EVEN-EVEN NUCLIDES; LOW-LYING STATES; ELECTRON-SCATTERING; COLLECTIVE STATES; GIANT-RESONANCES; MATRIX-ELEMENTS; FOLDING MODEL; ZR-90 AB We describe the application of a realistic self-consistent theory of finite Fermi systems to the ground and low excited states of the Zr-90,Zr-92,Zr-94,Zr-96 isotopes. Results were obtained for the ground, 2(1)(+) and 3(1)(-) states in each nucleus, and for the lowest 4(+), 5(-), 6(+) and 8(+) states in Zr-90. Transition densities were generated for the excitation of each of these states and their properties examined. Transition potentials for their excitation by hadronic inelastic scattering were constructed by folding with appropriate interactions between the projectile and each target nucleon, The calculated inelastic scattering cross sections are compared in detail with experimental results, particularly those for alpha particles at 35.4 MeV and Li-6 at 70 MeV. The implications of any discrepancies found are discussed. In addition, the theoretical results were used as ''experimental'' data in order to test the validity of using various simple models for the analysis of data. C1 OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37831 USA. UNIV TENNESSEE, DEPT PHYS & ASTRON, KNOXVILLE, TN 37996 USA. IV KURCHATOV ATOM ENERGY INST, RUSSIAN RES CTR, MOSCOW 123182, RUSSIA. OBNINSK PHYS & POWER ENGN INST, OBNINSK 249020, KALUGA, RUSSIA. RP OAK RIDGE NATL LAB, JOINT INST HEAVY ION RES, OAK RIDGE, TN 37831 USA. NR 53 TC 21 Z9 22 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 8 PY 1996 VL 600 IS 2 BP 193 EP 235 DI 10.1016/0375-9474(96)00032-2 PG 43 WC Physics, Nuclear SC Physics GA UL021 UT WOS:A1996UL02100003 ER PT J AU Sigl, G AF Sigl, G TI Weak interactions in supernova cores and saturation of nucleon spin fluctuations SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRAL CURRENT INTERACTIONS; DENSE MATTER; HOT; AXIONS; BREMSSTRAHLUNG; NEUTRINOS; EMISSION; STARS AB Extrapolation of perturbative nucleon spin fluctuation rates seems to suggest a strong suppression of weak interactions in supernova cores. We derive a generalized f sum rule for the dynamical spin-density structure function which relates the spin fluctuation rate to the average nuclear interaction energy. For a bremsstrahlung-like structure function profile we show that, instead of strongly decreasing, the neutrino scattering cross section is roughly density independent, and axion emissivities increase somewhat slower than the lowest order rates toward the center of a hot supernova core. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Sigl, G (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 28 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2625 EP 2628 DI 10.1103/PhysRevLett.76.2625 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000006 ER PT J AU Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, R Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, J Sung, M White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Freyberger, A Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Cinabro, D Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, FE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V AF Alam, MS Kim, IJ Ling, Z Mahmood, AH ONeill, JJ Severini, H Sun, CR Timm, S Wappler, F Duboscq, JE Fulton, R Fujino, D Gan, KK Honscheid, K Kagan, H Kass, R Lee, J Sung, M White, C Wanke, R Wolf, A Zoeller, MM Fu, X Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD Jones, SL Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Avery, P Freyberger, A Prescott, C Yang, S Yelton, J Brandenburg, G Briere, RA Cinabro, D Liu, T Saulnier, M Wilson, R Yamamoto, H Browder, TE Li, F Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, J Gladding, FE Gollin, GD Palmer, M Selen, M Thaler, JJ Edwards, KW McLean, KW Ogg, M Bellerive, A Britton, DI Janicek, R MacFarlane, DB Patel, PM Spaan, B Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Copty, N Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Kubota, Y Lattery, M Nelson, JK Patton, S Poling, R Riehle, T Savinov, V TI Tau decays into three charged leptons and two neutrinos SO PHYSICAL REVIEW LETTERS LA English DT Article ID LIBRARY AB We search for the radiative leptonic tau decays tau --> ee(+) e(-)nu(tau)nu(e) and tau --> mu e(+)e(-)nu(tau)nu(mu) using 3.60 fb(-1) of data collected by the CLEO-II experiment at the Cornell Electron Storage Ring. We present a first observation of the tau --> ee(+)e(-)nu(tau)nu(e) process. For this channel we measure the branching fraction B(tau --> ee(+)e(-)nu(tau)nu(e)) = (2.7(-1.1-0.4-0.3)(+1.5+0.4+0.1)) X 10(-5). An upper limit is established for the second channel: B(tau --> mu e(+)e(-)nu(tau)nu(mu)) < 3.2 X 10(-5) at 90% C.L. Both results are consistent with the rates expected from standard model predictions. C1 OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. INST PARTICLE PHYS,MONTREAL,PQ,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. RP Alam, MS (reprint author), SUNY ALBANY,ALBANY,NY 12222, USA. RI Schaffner, Stephen/D-1189-2011; Britton, David/F-2602-2010; Briere, Roy/N-7819-2014; OI Britton, David/0000-0001-9998-4342; Briere, Roy/0000-0001-5229-1039; Bean, Alice/0000-0001-5967-8674 NR 13 TC 6 Z9 7 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2637 EP 2641 DI 10.1103/PhysRevLett.76.2637 PG 5 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000009 ER PT J AU Radha, PB Dean, DJ Koonin, SE Kuo, TTS Langanke, K Poves, A Retamosa, J Vogel, P AF Radha, PB Dean, DJ Koonin, SE Kuo, TTS Langanke, K Poves, A Retamosa, J Vogel, P TI Shell model Monte Carlo method for two-neutrino double beta decay SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEI AB Shell model Monte Carlo techniques are used to calculate two-neutrino double beta decay matrix elements. We test the approach against direct diagonalization for Ca-48 in the complete pf shell using the KB3 interaction. The method is then applied to the decay of Ge-76 in the (0f(5/2), 1p,0g(9/2)) model space using a newly calculated realistic interaction. Our result for the matrix element is 0.12 +/- 0.05 MeV(-1), in reasonable agreement with the experimental value. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37381. SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. UNIV AUTONOMA MADRID,DEPT FIS TEOR C XI,E-28049 MADRID,SPAIN. CALTECH,DIV PHYS MATH & ASTRON,PASADENA,CA 91125. RP Radha, PB (reprint author), CALTECH,WK KELLOGG RADIAT LAB,PASADENA,CA 91125, USA. RI Poves, Alfredo/L-2594-2013; OI Poves, Alfredo/0000-0001-7539-388X; Dean, David/0000-0002-5688-703X NR 19 TC 25 Z9 25 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2642 EP 2645 DI 10.1103/PhysRevLett.76.2642 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000010 ER PT J AU Dorner, R Vogt, T Mergel, V Khemliche, H Kravis, S Cocke, CL Ullrich, J Unverzagt, M Spielberger, L Damrau, M Jagutzki, O Ali, I Weaver, B Ullman, K Hsu, CC Jung, M Kanter, EP Sonntag, B Prior, MH Rotenberg, E Denlinger, J Warwick, T Manson, ST SchmidtBocking, H AF Dorner, R Vogt, T Mergel, V Khemliche, H Kravis, S Cocke, CL Ullrich, J Unverzagt, M Spielberger, L Damrau, M Jagutzki, O Ali, I Weaver, B Ullman, K Hsu, CC Jung, M Kanter, EP Sonntag, B Prior, MH Rotenberg, E Denlinger, J Warwick, T Manson, ST SchmidtBocking, H TI Ratio of cross sections for double to single ionization of He by 85-400 eV photons SO PHYSICAL REVIEW LETTERS LA English DT Article ID DOUBLE PHOTOIONIZATION; RARE-GASES; HELIUM; IMPACT; NE AB The ratio of double to single ionization of He by 85-300 eV photons has been measured using cold target recoil ion momentum spectroscopy. This technique allows the elimination of all possible systematic errors discussed so far in the literature on this subject. We find the ratio in this energy range to be about 25% lower than previously assumed. C1 UNIV FRANKFURT,INST KERNPHYS,D-60486 FRANKFURT,GERMANY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. GESELL SCHWERIONENFORSCH MBH,D-64291 DARMSTADT,GERMANY. ARGONNE NATL LAB,ARGONNE,IL 60439. NATL TSING HUA UNIV,HSINCHU 300,TAIWAN. DESY,HASYLAB,D-22603 HAMBURG,GERMANY. UNIV OREGON,DEPT PHYS,EUGENE,OR 97403. UNIV WISCONSIN,DEPT PHYS,MILWAUKEE,WI 53211. GEORGIA STATE UNIV,DEPT PHYS & ASTRON,ATLANTA,GA 30303. RP Dorner, R (reprint author), KANSAS STATE UNIV,DEPT PHYS,CARDWELL HALL,MANHATTAN,KS 66506, USA. RI Rotenberg, Eli/B-3700-2009; Doerner, Reinhard/A-5340-2008 OI Rotenberg, Eli/0000-0002-3979-8844; Doerner, Reinhard/0000-0002-3728-4268 NR 35 TC 87 Z9 87 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 APR 8 PY 1996 VL 76 IS 15 BP 2654 EP 2657 DI 10.1103/PhysRevLett.76.2654 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000013 ER PT J AU Alexeeva, LV Anferov, VA Crandell, DA Hu, SQ Krisch, AD Phelps, RA Ratner, LG Varzar, SM Wong, VK Lee, SY Rinckel, T Schwandt, P Sperisen, F Stephenson, EJ vonPrzewoski, B Baiod, R Martin, PS Russell, AD Sato, H Minty, MG AF Alexeeva, LV Anferov, VA Crandell, DA Hu, SQ Krisch, AD Phelps, RA Ratner, LG Varzar, SM Wong, VK Lee, SY Rinckel, T Schwandt, P Sperisen, F Stephenson, EJ vonPrzewoski, B Baiod, R Martin, PS Russell, AD Sato, H Minty, MG TI Crossing intrinsic depolarizing resonances by varying a partial Siberian snake SO PHYSICAL REVIEW LETTERS LA English DT Article ID ACCELERATION AB We recently forced a 140 MeV polarized proton beam to cross intrinsic depolarizing resonances by varying a partial Siberian snake's strength for different values of the vertical and horizontal betatron tunes nu(y) and nu(x). A weak second-order intrinsic resonance was observed in the nu(x) sweep; moreover, an unexpected partial spin flip was found in the nu(y) sweep. We also varied the snake ramp time to identify the nu(y) and nu(x) regions where the resonance crossings occurred during the snake variation; in these crossings the polarization partially deviated from Froissart-Stora behavior. C1 INDIANA UNIV,CYCLOTRON FACIL,BLOOMINGTON,IN 47408. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. NATL LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 305,JAPAN. STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. MOSCOW MV LOMONOSOV STATE UNIV,MOSCOW 117234,RUSSIA. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Alexeeva, LV (reprint author), UNIV MICHIGAN,RANDALL LAB PHYS,ANN ARBOR,MI 48109, USA. RI Varzar, Sergey/C-8914-2014 NR 24 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2714 EP 2717 DI 10.1103/PhysRevLett.76.2714 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000028 ER PT J AU Taylor, G Strachan, JD Budny, RV Ernst, DR AF Taylor, G Strachan, JD Budny, RV Ernst, DR TI Fusion heating in a deuterium-tritium tokamak plasma SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRON EMISSION; TFTR AB Evidence for fusion heating in the core of a deuterium-tritium (D-T) tokamak plasma is reported for the first time. Electron temperature profile data were analyzed for differences between D-T, D, and T plasmas in the Tokamak Fusion Test Reactor. Data from D and D-T plasmas with similar plasma parameters were averaged to minimize isotopic effects. The electron temperature in D-T plasmas was systematically higher than in D or T plasmas. The temperature difference between D-T and D plasmas with similar confinement times is consistent with alpha-particle heating of electrons. C1 MIT,CAMBRIDGE,MA 02139. RP Taylor, G (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Ernst, Darin/A-1487-2010 OI Ernst, Darin/0000-0002-9577-2809 NR 17 TC 38 Z9 38 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2722 EP 2725 DI 10.1103/PhysRevLett.76.2722 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000030 ER PT J AU McGraw, R Laaksonen, A AF McGraw, R Laaksonen, A TI Scaling properties of the critical nucleus in classical and molecular-based theories of vapor-liquid nucleation SO PHYSICAL REVIEW LETTERS LA English DT Article AB Scaling relations are developed for the number g* of molecules in the critical nucleus and the nucleation barrier height W*. Density functional (DF) calculations for vapor-liquid nucleation confirm these relations and show systematic departure of the ratio W*/g*Delta mu from its classical value of 1/2 with increasing difference Delta mu in the chemical potential between the supersaturated vapor and bulk condensed phase. Discrepancies between classical and DF nucleation theories and between the classical theory and experiment are interpreted using these results. C1 UNIV HELSINKI,DEPT PHYS,SF-00014 HELSINKI,FINLAND. RP McGraw, R (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,ENVIRONM CHEM DIV,UPTON,NY 11973, USA. RI Laaksonen, Ari/B-5094-2011 OI Laaksonen, Ari/0000-0002-1657-2383 NR 16 TC 116 Z9 116 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2754 EP 2757 DI 10.1103/PhysRevLett.76.2754 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000038 ER PT J AU Mun, MO Lee, SI Lee, WC Canfield, PC Cho, BK Johnston, DC AF Mun, MO Lee, SI Lee, WC Canfield, PC Cho, BK Johnston, DC TI Vortex glass and lattice melting transitions in a YNi2B2C single crystal SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTORS; SQUID PICOVOLTOMETRY; YBA2CU3O7; STATE AB The mixed state of the weakly disordered superconductor YNi2B2C is found to be similar to that of high-T-c materials due to its large fluctuations. The very sharp resistive transition with a kink and the S-shaped I-V curve appear below H = 1 T indicating a lattice melting transition. The scaling behavior of the vortex glass transition in R-T and I-V curves for H greater than or equal to 2 T is observed with critical exponents nu = 1.23 +/- 0.02 and z = 5.46 +/- 0.32, which are field independent. The vortex solid state changes from the vortex lattice at low fields to the vortex glass at high fields due to a field-enhanced pinning effect. The type of multicriticality is not yet conclusive. C1 SOOKMYUNG WOMENS UNIV,DEPT PHYS,SEOUL 140742,SOUTH KOREA. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES LAB,AMES,IA 50011. RP Mun, MO (reprint author), POHANG UNIV SCI & TECHNOL,DEPT PHYS,POHANG 790784,SOUTH KOREA. RI Canfield, Paul/H-2698-2014 NR 25 TC 58 Z9 58 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2790 EP 2793 DI 10.1103/PhysRevLett.76.2790 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000047 ER PT J AU McIlroy, DN Waldfried, C Li, DQ Pearson, J Bader, SD Huang, DJ Johnson, PD Sabiryanov, RF Jaswal, SS Dowben, PA AF McIlroy, DN Waldfried, C Li, DQ Pearson, J Bader, SD Huang, DJ Johnson, PD Sabiryanov, RF Jaswal, SS Dowben, PA TI Oxygen induced suppression of the surface magnetization of Gd(0001) SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHOTOEMISSION; MAGNETISM AB The effects of oxygen adsorption on the surface magnetization of Gd(0001) have been determined by measuring the polarization of the Gd 4f core levels and the oxygen induced states with spin-resolved photoemission. Calculations of the partial density of states of O/Gd(0001) using the LMTO-ASA method support the photoemission measurements, which indicate that oxidation occurs at low coverages. The loss of surface magnetic order with oxygen exposure is explained in terms of decreasing indirect coupling. C1 UNIV NEBRASKA,CTR MAT RES & ANAL,BEHLEN LAB PHYS,LINCOLN,NE 68588. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. BROOKHAVEN NATL LAB,DEPT PHYS 510B,UPTON,NY 11973. RP McIlroy, DN (reprint author), UNIV NEBRASKA,DEPT PHYS & ASTRON,LINCOLN,NE 68588, USA. RI Bader, Samuel/A-2995-2013 NR 16 TC 19 Z9 19 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2802 EP 2805 DI 10.1103/PhysRevLett.76.2802 PG 4 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000050 ER PT J AU Moretto, LG Ghetti, R Phair, L Tso, K Wozniak, GJ AF Moretto, LG Ghetti, R Phair, L Tso, K Wozniak, GJ TI Probing the nuclear liquid-gas phase transition - Comment SO PHYSICAL REVIEW LETTERS LA English DT Article RP Moretto, LG (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 1 TC 36 Z9 36 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 8 PY 1996 VL 76 IS 15 BP 2822 EP 2822 DI 10.1103/PhysRevLett.76.2822 PG 1 WC Physics, Multidisciplinary SC Physics GA UE190 UT WOS:A1996UE19000055 ER PT J AU Li, SP Eastman, JA Li, Z Foster, CM Newnham, RE Cross, LE AF Li, SP Eastman, JA Li, Z Foster, CM Newnham, RE Cross, LE TI Size effects in nanostructured ferroelectrics SO PHYSICS LETTERS A LA English DT Article ID PHASE-TRANSITIONS; LANDAU THEORY AB The finite size effect in ferroelectrics results in structural instability, imposing a limitation of physical sizes and dimensions of materials in which electric dipoles can be sustained. To evaluate the ultimate limitation of physical sizes for a stable polar phase, the characteristic sizes, i.e., anisotropic correlation lengths of electric dipoles, in a ferroelectric have been examined by considering the surface effect. The size dependence on the Curie temperature in particular is calculated with consideration of crystallographic anisotropy. The mean-field theory shows that the limitation of transverse critical sizes is strongly dependent upon the thickness. In turn, the limitation of the critical thickness is also closely associated with the transverse critical sizes. C1 PENN STATE UNIV,MAT RES LAB,UNIVERSITY PK,PA 16802. RP Li, SP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 34 TC 106 Z9 109 U1 2 U2 24 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD APR 8 PY 1996 VL 212 IS 6 BP 341 EP 346 DI 10.1016/0375-9601(96)00077-1 PG 6 WC Physics, Multidisciplinary SC Physics GA UD723 UT WOS:A1996UD72300009 ER PT J AU Hoberg, JO Claffey, DJ AF Hoberg, JO Claffey, DJ TI Cyclopropanation of unsaturated sugars with ethyl diazoacetate SO TETRAHEDRON LETTERS LA English DT Article ID ALLYLIC ALCOHOLS AB The cyclopropanation of unsaturated sugars with ethyl diazoacetate and a metal catalyst provides ester-substituted 12-C-methylene carbohydrates in good to excellent yields, Ring opening of the cyclopropane has also been achieved providing C-2 branched glycosyl bromides. Copyright (C) 1996 Elsevier Science Ltd RP Hoberg, JO (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 25 TC 51 Z9 51 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD APR 8 PY 1996 VL 37 IS 15 BP 2533 EP 2536 DI 10.1016/0040-4039(96)00335-8 PG 4 WC Chemistry, Organic SC Chemistry GA UE233 UT WOS:A1996UE23300007 ER PT J AU Orji, CC Kelly, J Ashburn, DA Silks, LA AF Orji, CC Kelly, J Ashburn, DA Silks, LA TI First synthesis of beta-2'-deoxy[9-N-15] adenosine SO JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 LA English DT Article AB We report the first synthesis of beta-2'-deoxy[9-N-15] adenosine: the last of the singly labelled N-15 beta-21-deoxyadenosines to be synthesized. Using commercially available 5-amino-4,6-dichloropyrimidine and 2-10 equivalents of (NH3)-N-15, beta-2'-deoxy[9-N-15]adenosine has been constructed in four steps in good overall yield. C1 LOS ALAMOS NATL LAB,NIH STABLE ISOTOPES RESOURCE,BIOSCI & BIOTECHNOL SECT,LOS ALAMOS,NM 87545. NR 19 TC 8 Z9 8 U1 1 U2 2 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0300-922X J9 J CHEM SOC PERK T 1 JI J. Chem. Soc.-Perkin Trans. 1 PD APR 7 PY 1996 IS 7 BP 595 EP 597 DI 10.1039/p19960000595 PG 3 WC Chemistry, Organic SC Chemistry GA UF123 UT WOS:A1996UF12300002 ER PT J AU Frishman, AM Hoffman, DK Rakauskas, RJ Kouri, DJ AF Frishman, AM Hoffman, DK Rakauskas, RJ Kouri, DJ TI Distributed approximating functional approach to fitting and predicting potential surfaces .1. Atom-atom potentials SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PROPAGATOR AB A procedure is presented for obtaining an analytical representation of the potential energy for a diatomic system, knowing the potential only at finite number of internuclear separations. The approach is based on the distributed approximating functional (DAF), which has the property of delivering comparable accuracy for approximating a function and its derivatives, given such limited input data. The method is illustrated by applications to several atom-atom potentials, including those for the Li-2 and H-2 systems. C1 UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77204. UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. VILNIUS UNIV,FAC PHYS,VILNIUS 2009,LITHUANIA. VILNIUS UNIV,INST APPL SCI,VILNIUS 2009,LITHUANIA. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. NR 10 TC 25 Z9 25 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 5 PY 1996 VL 252 IS 1-2 BP 62 EP 70 DI 10.1016/S0009-2614(96)00150-9 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UG374 UT WOS:A1996UG37400008 ER PT J AU Catasti, P Bradbury, EM Gupta, G AF Catasti, P Bradbury, EM Gupta, G TI Structure and polymorphism of HIV-1 third variable loops SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID PRINCIPAL NEUTRALIZING DETERMINANT; ENVELOPE V3 LOOP; CELL TROPISM; ANTIBODIES; SEQUENCE; GLYCOPROTEIN; CONFORMATION; EPITOPE; PROTEIN; DOMAIN AB The third variable (V3) loop of HIV-1 surface glycoprotein, gp120, has been the target of neutralizing antibodies, However, sequence variation inside the V3 loop diminishes its effectiveness as a potential vaccine against HIV-1, The elusive nature of the V3 loop structure prompted us to carry out a systematic study on different isolates in an attempt to identify a common structural motif in the V3 loop regardless of the amino acid sequence variability, We have previously determined the structural features of two V3 loops: V3 Thailand and V3 RIN, In this paper, we present the structure of two other variants: V3 Haiti and V3 RF. Our results show that similar secondary structures are observed in all the four V3 loops: a GPG(R/K/Q) crest in the center of the neutralizing domain, two extended regions flanking the central crest, and a helical region in the C-terminal domain, For the Haitian V3 loop, we also show how the conserved structural features are masked through a conformational switch encoded in the amino acid sequences on the C-terminal side of the GPGK crest. C1 LOS ALAMOS NATL LAB,THEORET BIOL & BIOPHYS GRP,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616. FU NIAID NIH HHS [R01 AI32891-01A2] NR 28 TC 57 Z9 61 U1 1 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 APR 5 PY 1996 VL 271 IS 14 BP 8236 EP 8242 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UD600 UT WOS:A1996UD60000057 PM 8626517 ER PT J AU Mary, TA Evans, JSO Vogt, T Sleight, AW AF Mary, TA Evans, JSO Vogt, T Sleight, AW TI Negative thermal expansion from 0.3 to 1050 Kelvin in ZrW2O8 SO SCIENCE LA English DT Article ID OXYGEN AB Negative thermal expansion was found for ZrW2O8 from 0.3 kelvin to its decomposition temperature of about 1050 kelvin. Both neutron and x-ray diffraction data were used to solve and refine the structure of this compound at various temperatures. Cubic symmetry persists for ZrW2O8 over its entire stability range. Thus, the negative thermal expansion behavior is isotropic, Essentially the same behavior was found for isostructural HfW2O8. No other materials are known to exhibit such behavior over such a broad temperature range. These materials are finding applications as components in composites in order to reduce the composites' overall thermal expansion to near zero. C1 OREGON STATE UNIV,DEPT CHEM,CORVALLIS,OR 97331. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RI Vogt, Thomas /A-1562-2011; Evans, John/E-6345-2012 OI Vogt, Thomas /0000-0002-4731-2787; Evans, John/0000-0001-6305-6341 NR 16 TC 822 Z9 899 U1 18 U2 200 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 5 PY 1996 VL 272 IS 5258 BP 90 EP 92 DI 10.1126/science.272.5258.90 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UD597 UT WOS:A1996UD59700044 ER PT J AU Rao, LF Hwang, SJ King, TS Pruski, M AF Rao, LF Hwang, SJ King, TS Pruski, M TI Characterization of CO in Rh-6(CO)(16)/NaY clusters and isolated Rh+(CO)(2)/NaY by solid-state C-13 NMR spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID MAGIC-ANGLE; ADSORBED STATES; PROPYLENE HYDROFORMYLATION; DISPERSED METALS; RHODIUM; ZEOLITES; DICARBONYLS; RESOLUTION; EXCHANGE; SAMPLES AB Solid-state NMR spectroscopy of C-13 is used to structurally characterize and quantify carbonyl groups in Rh-6(CO)(16) and Rh+(CO)(2) complexes entrapped in NaY zeolite. MAS NMR line shape simulations show that the dicarbonyl groups present in Rh-6(CO)16 and Rh+(CO)2 have the same shielding parameters (sigma(150) similar to 178 ppm, CSA similar to 400 ppm, and eta similar to 0.2) but exhibit greatly different spin-lattice relaxation rates. Bridged groups exist only in clusters and are bonded to three Rh atoms. Their shielding parameters [sigma(150) similar to 251 ppm, CSA similar to 180 ppm, and negligible anisotropy (eta)] differ from bulk Rh-6(CO)(16) and from those found earlier for CO bridged between two Rh atoms. The Rh-6:Rh+ ratio can be measured directly from the MAS spectra or from the relaxation data. The residual broadening of 150-200 Hz in the MAS spectra is due to distribution of isotropic resonances in the sample. All CO species are immobile at room temperature on the NMR time scale (of the order of a millisecond), whereas slow exchange between dicarbonyls on hexarhodium clusters and isolated rhodium cations was found at 380 K. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM ENGN,AMES,IA 50011. NR 21 TC 10 Z9 11 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 4 PY 1996 VL 100 IS 14 BP 5668 EP 5671 DI 10.1021/jp9536211 PG 4 WC Chemistry, Physical SC Chemistry GA UD604 UT WOS:A1996UD60400012 ER PT J AU Ree, FH Pitz, WJ vanThiel, M Souers, PC AF Ree, FH Pitz, WJ vanThiel, M Souers, PC TI Overabundance of carbon monoxide in calorimetry tests SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article AB The amount of carbon monoxide recovered from calorimetry tests of high explosives is far larger than the amount predicted by equilibrium calculations. The present kinetics study of PETN ([(nitro(oxy)methyl]propanediol dinitrate) has revealed that the cooling of the calorimetry bomb after detonation of a PETN sample sufficiently slows those reactions that would otherwise lead to equilibrium so that these reactions are effectively frozen in the time scale of recovery of detonation products. Among these reactions, those that can create CH4 are the most important ones. Their rates are generally slow at all temperatures relevant to calorimetry tests. This and the slowing down of a reaction, CO + H2O --> H-2 + CO2, at temperatures below 1500 K are the main cause of the freeze-out of CO. A possible slow rate of the soot formation (i.e., condensed carbon) is not responsible for it. The sensitivity of the present result to the cooling rate of the detonation products and to free radicals is also examined. RP Ree, FH (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 14 TC 4 Z9 5 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 4 PY 1996 VL 100 IS 14 BP 5761 EP 5765 DI 10.1021/jp952241c PG 5 WC Chemistry, Physical SC Chemistry GA UD604 UT WOS:A1996UD60400025 ER PT J AU Tarver, CM Chidester, SK Nichols, AL AF Tarver, CM Chidester, SK Nichols, AL TI Critical conditions for impact- and shock-induced hot spots in solid explosives SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID CONDENSED-PHASE DECOMPOSITION; GASEOUS PYROLYSIS PRODUCTS; ENERGETIC MATERIALS; THERMAL-DECOMPOSITION; TEMPORAL BEHAVIORS; OCTAHYDRO-1,3,5,7-TETRANITRO-1,3,5,7-TETRAZOCINE; RATES AB Chemical kinetic thermal decomposition models of pressed solid high explosives containing octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and triaminotrinitrobenzene (TATB), which accurately calculate the times to explosion at various initial temperatures measured in the one-dimensional time to explosion (ODTX) test, are extended to higher temperatures to predict the critical temperatures, times to explosion, and dimensions of the impact- and shock-induced hot spots that are known to control the ignition of exothermic reaction in solid explosives. The effects of hot spot geometry and surrounding temperature on the critical hot spot conditions are investigated. Since hot spot temperatures and dimensions cannot be measured experimentally, these estimated temperatures, sizes, and times required for exothermic chemical reaction provide a means to evaluate proposed physical mechanisms of hot spot formation in accident scenarios involving impact (friction and shear) and shock compression of solid explosives. RP Tarver, CM (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 37 TC 163 Z9 165 U1 0 U2 47 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 4 PY 1996 VL 100 IS 14 BP 5794 EP 5799 DI 10.1021/jp953123s PG 6 WC Chemistry, Physical SC Chemistry GA UD604 UT WOS:A1996UD60400029 ER PT J AU Butenhoff, TJ Goemans, MGE Buelow, SJ AF Butenhoff, TJ Goemans, MGE Buelow, SJ TI Mass diffusion coefficients and thermal diffusivity in concentrated hydrothermal NaNO3 solutions SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SUPERCRITICAL CARBON-DIOXIDE; FORCED RAYLEIGH-SCATTERING; TRANSPORT-PROPERTIES; AQUEOUS-SOLUTIONS; TRACER DIFFUSION; DILUTE-SOLUTIONS; WATER; FLUIDS; LIQUIDS; HYDROCARBONS AB Binary mass diffusion coefficients and thermal diffusivities for hydrothermal sodium nitrate solutions as a function of pressure (270 < P < 1000 bar), temperature (400 < T < 500 degrees C), and concentration (0.25 < C < 3.0 m) were measured by the laser-induced grating technique, In concentrated hydrothermal NaNO3 systems, the critical slowing down was significant as far as 300 bar from the phase-separation pressure, resulting in binary diffusion coefficients near the critical point that are comparable to values at ambient conditions, Further from the critical point the mass diffusion coefficients plateaued at their ordinary values. Ordinary binary mass diffusion was about 15 times faster than at 25 degrees C and atmospheric pressure. The ordinary binary mass diffusion coefficients were compared with predictions from hydrodynamic diffusion theory. Experimental results agreed well with predictions from the Stokes-Einstein equation, where the diffusing species was best represented by a hydrated contact ion pair. The Wilke-Chang correlation also yielded good predictions when the solute molar volume was defined as the volume of the hydrated contact ion pair. Predictions can be improved by about 10% if the degree of association can be calculated. Thermal diffusion coefficients (Soret effect) at 450 degrees C were also measured and are about 250 times faster than at ambient conditions. The laser-induced grating technique was found to be highly complementary to the Taylor dispersion technique for diffusion measurements in hydrothermal systems. The grating technique;works best at higher concentrations and near critical points, the two regimes where the Taylor dispersion technique becomes increasingly more difficult. C1 LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,LOS ALAMOS,NM 87545. UNIV TEXAS,DEPT CIVIL ENGN,ENVIRONM & WATER RESOURCES ENGN PROGRAM,AUSTIN,TX 78712. NR 88 TC 31 Z9 31 U1 2 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 APR 4 PY 1996 VL 100 IS 14 BP 5982 EP 5992 DI 10.1021/jp952975p PG 11 WC Chemistry, Physical SC Chemistry GA UD604 UT WOS:A1996UD60400054 ER PT J AU Shkrob, IA Sauer, MC Trifunac, AD AF Shkrob, IA Sauer, MC Trifunac, AD TI High-mobility ions in the viscous hydrocarbon squalane SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID DETECTED MAGNETIC-RESONANCE; ALKANE RADICAL-CATIONS; PULSE-RADIOLYSIS; IRRADIATED CYCLOHEXANE; ABSORPTION-SPECTRA; ELECTRON-TRANSFER; RATE CONSTANTS; EXCITED-STATE; POSITIVE-IONS; SOLVENT AB Pulsed radiolysis, laser flash photolysis, and de photoconductivity were used to measure the rates of ion-molecule reactions in the viscous hydrocarbon squalane (2,6,10,15,19,23-hexamethyltetracosane). It was found that squalane radical cation (hole) is scavenged with a rate constant similar to(5-7) x 10(9) mol(-1) dm(3) s(-1), which is 4-10 times faster than other charge transfer reactions in squalane. In this sense, squalane is similar to cyclohexane, methycyclohexane, and decalins, yielding high-mobility ions (HMIs) on radiolysis. While in squalane the hole is more mobile than molecular ions, its mobility (estimated as 2 x 10(-4) cm(2)/(V s)) is much lower than that of the HMIs in cycloalkanes. The lifetime of the squalane hole in the absence of scavengers is 20 +/- 5 ns. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 58 TC 16 Z9 16 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 4 PY 1996 VL 100 IS 14 BP 5993 EP 6002 DI 10.1021/jp9532374 PG 10 WC Chemistry, Physical SC Chemistry GA UD604 UT WOS:A1996UD60400055 ER PT J AU Brodsky, SJ Gabadadze, GT Kataev, AL Lu, HJ AF Brodsky, SJ Gabadadze, GT Kataev, AL Lu, HJ TI The generalized Crewther relation in QCD and its experimental consequences SO PHYSICS LETTERS B LA English DT Article ID DEEP INELASTIC-SCATTERING; QUANTUM-CHROMODYNAMIC CORRECTIONS; TO-LEADING ORDER; POWER CORRECTIONS; E+E ANNIHILATION; SUM-RULES; RENORMALIZATION-GROUP; PERTURBATIVE APPROACH; FIELD-THEORIES; ANOMALIES AB We use the BLM scale-fixing prescription to derive a renormalization-scheme invariant relation between the coefficient function for the Bjorken sum rule for polarized deep inelastic scattering and the R-ratio for the e(+)e(-) annihilation cross section. This relation provides a generalization of the Crewther relation to non-conformally invariant gauge theories. The derived relations allow one to calculate unambiguously without renormalization scale or scheme ambiguity the effective charges of the polarized Bjorken and the Gross-Llewellen Smith sum rules from the experimental value for the effective charge associated with R-ratio, Present data are consistent with the generalized Crewther relations, but measurements at higher precision and energies will be needed to decisively test these fundamental relations in QCD. C1 RUTGERS STATE UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08855. RUSSIAN ACAD SCI,INST NUCL RES,MOSCOW 117312,RUSSIA. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. RP Brodsky, SJ (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 68 TC 83 Z9 84 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 4 PY 1996 VL 372 IS 1-2 BP 133 EP 140 DI 10.1016/0370-2693(96)00057-3 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UE454 UT WOS:A1996UE45400022 ER PT J AU Giele, WT Keller, S Laenen, E AF Giele, WT Keller, S Laenen, E TI QCD corrections to W boson plus heavy quark production at the Tevatron SO PHYSICS LETTERS B LA English DT Article ID HIGHER-ORDER CORRECTIONS; JET CROSS-SECTIONS; DISTRIBUTIONS; ANNIHILATION AB The next-to-leading order QCD correction to the production of a W boson in association with a jet containing a heavy quark are presented. The calculation is fully differential in the final state particle momenta and includes the mass of the heavy quark. We study for the case of the Tevatron the sensitivity of the cross section to the strange quark distribution function, the dependence of the cross section on the heavy quark mass, the transverse momentum distribution of the jet containing the heavy quark, and the momentum distribution of the heavy quark in the jet. C1 CERN,TH DIV,CH-1211 GENEVA 23,SWITZERLAND. RP Giele, WT (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,MS 106,BATAVIA,IL 60510, USA. NR 33 TC 40 Z9 40 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 4 PY 1996 VL 372 IS 1-2 BP 141 EP 149 DI 10.1016/0370-2693(96)00078-0 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UE454 UT WOS:A1996UE45400023 ER PT J AU Keaton, GL AF Keaton, GL TI Large-N baryons, chiral loops, and the emergence of the constituent quark SO PHYSICS LETTERS B LA English DT Article ID HYPERFINE MASS SPLITTINGS; PERTURBATION-THEORY; HEAVY-QUARK; QCD AB Meson loop corrections to baryon axial currents are computed in the 1/N expansion. It is already known that the one-loop corrections are suppressed by a factor 1/N; here it is shown that the two-loop corrections are suppressed by 1/N-2. To leading order, these corrections are exactly what would be calculated in the constituent quark model. Some applications are discussed. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA. LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. NR 26 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 4 PY 1996 VL 372 IS 1-2 BP 150 EP 156 DI 10.1016/0370-2693(96)00034-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UE454 UT WOS:A1996UE45400024 ER PT J AU Abreu, P Adam, W Adye, T Agasi, E Ajinenko, I Aleksan, R Alekseev, GD Alemany, R Allport, PP Almehed, S Amaldi, U Amato, S Andreazza, A Andrieux, ML Antilogus, P Apel, WD Arnoud, Y Asman, B Augustin, JE Augustinus, A Baillon, P Bambade, P Barao, F Barate, R Barbi, M Bardin, DY Baroncelli, A Barring, O Barrio, JA Bartl, W Bates, MJ Battaglia, M Baubillier, M Baudot, J Becks, KH Begalli, M Beilliere, P Belokopytov, Y Belous, K Benvenuti, AC Berggren, M Bertrand, D Bianchi, F Bigi, M Bilenky, MS Billoir, P Bloch, D Blume, M Blyth, S Bolognese, T Bonesini, M Bonivento, W Booth, PSL Borisov, G Bosio, C Bosworth, S Botner, O Boudinov, E Bouquet, B Bourdarios, C Bowcock, TJV Bozzo, M Branchini, P Brand, KD Brenke, T Brenner, RA Bricman, C Brillault, L Brown, RCA Bruckman, P Brunet, JM Bugge, L Buran, T Burgsmueller, T Buschmann, P Buys, A Cabrera, S Caccia, M Calvi, M Rozas, AJC Camporesi, T Canale, V Canepa, M Cankocak, K Cao, F Carena, F Carroll, L Caso, C Gimenez, MVC Cattai, A Cavallo, FR Cerrito, L Chabaud, V Charpentier, P Chaussard, L Chauveau, J Checchia, P Chelkov, GA Chen, M Chierici, R Chilapnikov, P Chochula, P Chorowicz, V Cindro, V Collins, P Contreras, JL Contri, R Cortina, E Cosme, G Cossutti, F Crawley, HB Crennell, D Crosetti, G Maestro, JC Czellar, S DahlJensen, E Dahm, J Dalmagne, B Dam, M Damgaard, G Dauncey, PD Davenport, M DaSilva, W Defoix, C Deghorain, A DellaRicca, G Delpierre, P Demaria, N DeAngelis, A DeBoer, W DeBrabandere, S DeClercq, C DelaVaissiere, C DeLotto, B DeMin, A DePaula, L DeSaintJean, C Dijkstra, H DiCiaccio, L Djama, F Dolbeau, J Donszelmann, M Doroba, K Dracos, M Drees, J Drees, KA Dris, M Dufour, Y Edsall, D Ehret, R Eigen, G Ekelof, T Ekspong, G Elsing, M Engel, JP Ershaidat, N Erzen, B Santo, ME Falk, E Fassouliotis, D Feindt, M Fenyuk, A Ferrer, A Filippas, TA Firestone, A Fisher, PA Foeth, H Fokitis, E Fontanelli, F Formenti, F Franek, B Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R FuldaQuenzer, F Fuster, J Galloni, A Gamba, D Gandelman, M Garcia, C Garcia, J Gaspar, C Gasparini, U Gavillet, P Gazis, EN Gele, D Gerber, JP Gerdyukov, L Gibbs, M Gokieli, R Golob, B Gopal, G Gorn, L Gorski, M Gouz, Y Gracco, V Graziani, E Grosdidier, G Grzelak, K Gumenyuk, S Gunnarsson, P Gunther, M Guy, J Hahn, S Hajduk, Z Hallgren, A Hamacher, K Hao, W Harris, FJ Hedberg, V Henriques, R Hernandez, JJ Herquet, P Herr, H Hessing, TL Higon, E Hilke, HJ Hill, TS Holmgren, SO Holt, PJ Holthuizen, D Hoorelbeke, S Houlden, M Hrubec, J Huet, K Hultqvist, K Jackson, JN Jacobsson, R Jalocha, P Janik, R Jarlskog, C Jarlskog, G Jarry, P JeanMarie, B Johansson, EK Jonsson, L Jonsson, P Joram, C Juillot, P Kaiser, M Kapusta, F Karafasoulis, K Karlsson, M Karvelas, E Katsanevas, S Katsoufis, EC Keranen, R Khohklov, Y Khomenko, BA Khovanski, NN King, B Kjaer, NJ Klein, H Klovning, A Kluit, P Koene, B Kokkinias, P Koratzinos, M Korcyl, K Kourkoumelis, C Kouznetsov, O Kramer, PH Krammer, M Kreuter, C Kronkvist, I Krumstein, Z Krupinski, W Kubinec, P Kucewicz, W Kurvinen, K Lacasta, C Laktineh, I Lamblot, S Lamsa, JW Lanceri, L Lane, DW Langefeld, P Last, I Laugier, JP Lauhakangas, R Leder, G Ledroit, F Lefebure, V Legan, CK Leitner, R Lemoigne, Y Lemonne, J Lenzen, G Lepeltier, V Lesiak, T Liko, D Lindner, R Lipniacka, A Lippi, I Loerstad, B Lokajicek, M Loken, JG Lopez, JM Loukas, D Lutz, P Lyons, L MacNaughton, J Maehlum, G Maio, A Malychev, V Mandl, F Marco, J Marco, R Marechal, B Margoni, M Marin, JC Mariotti, C Markou, A Maron, T MartinezRivero, C MartinezVidal, F Garcia, SMI Matorras, F Matteuzzi, C Matthiae, G Mazzucato, M McCubbin, M McKay, R McNulty, R Medbo, J Merk, M Meroni, C Meyer, S Meyer, WT Michelotto, M Migliore, E Mirabito, L Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Mundim, LM Murray, WJ Muryn, B Myatt, G Naraghi, F Navarria, FL Navas, S Nawrocki, K Negri, P Nemecek, S Neumann, W Neumeister, N Nicolaidou, R Nielsen, BS Nieuwenhuizen, M Nikolaenko, V Niss, P Nomerotski, A Normand, A OberschulteBeckmann, W Obraztsov, V Olshevski, AG Onofre, A Orava, R Osterberg, K Ouraou, A Paganini, P Paganoni, M Pages, P Palka, H Papadopoulou, TD Papageorgiou, K Pape, L Parkes, C Parodi, F Passeri, A Pegoraro, M Peralta, L Pernegger, H Pernicka, M Perrotta, A Petridou, C Petrolini, A Petrovyck, M Podobrin, O Pol, ME Polok, G Poropat, P Pozdniakov, V Prest, M Privitera, P Pukhaeva, N Pullia, A Radojicic, D Ragazzi, S Rahmani, H Rames, J Ratoff, PN Read, AL Reale, M Rebecchi, P Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, J Ridky, J Rinaudo, G Ripp, I Romero, A Roncagliolo, I Ronchese, P Roos, L Rosenberg, EI Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W RuhlmannKleider, V Ruiz, A Rybicki, K Saarikko, H Sacquin, Y Sadovsky, A Sajot, G Salt, J Sanchez, J Sannino, M Schimmelpfennig, M Schneider, H Schwickerath, U Schyns, MAE Sciolla, G Scuri, F Seager, P Sedykh, Y Segar, AM Seitz, A Sekulin, R Shellard, RC Siccama, I Siegrist, P Simonetti, S Simonetto, F Sisakian, AN Sitar, B Skaali, TB Smadja, G Smirnov, N Smirnova, O Smith, GT Solovianov, O Sosnowski, R SouzaSantos, D Spiriti, E Sponholz, P Squarcia, S Stanescu, C Stapnes, S Stavitski, I Stichelbaut, F Stocchi, A Strauss, J Strub, R Stugu, B Szczekowski, M Szeptycka, M Tabarelli, T Tavernet, JP Tchikilev, O Tilquin, A Timmermans, J Tkatchev, LG Todorov, T Toet, DZ Tomaradze, A Tome, B Tonazzo, A Tortora, L Transtromer, G Treille, D Trischuk, W Tristram, G Trombini, A Troncon, C Tsirou, A Turluer, ML Tyapkin, IA Tyndel, M Tzamarias, S Ueberschaer, B Ullaland, O Uvarov, V Valenti, G Vallazza, E VanderVelde, C VanEldik, J Vassilopoulos, N Vegni, G Ventura, L Venus, W Verbeure, F Verlato, M Vertogradov, LS Vilanova, D Vincent, P Vitale, L Vlasov, E Vodopyanov, AS Vrba, V Wahlen, H Walck, C Waldner, F Weierstall, M Weilhammer, P Weiser, C Wetherell, AM Wicke, D Wickens, JH Wielers, M Wilkinson, GR Williams, WSC Winter, M Witek, M Woschnagg, K Yip, K Yuschenko, O Zach, F Zaitsev, A Zalewska, A Zalewski, P Zavrtanik, D Zevgolatakos, E Zimin, NI Zito, M Zontar, D Zuberi, R Zucchelli, GC Zumerle, G AF Abreu, P Adam, W Adye, T Agasi, E Ajinenko, I Aleksan, R Alekseev, GD Alemany, R Allport, PP Almehed, S Amaldi, U Amato, S Andreazza, A Andrieux, ML Antilogus, P Apel, WD Arnoud, Y Asman, B Augustin, JE Augustinus, A Baillon, P Bambade, P Barao, F Barate, R Barbi, M Bardin, DY Baroncelli, A Barring, O Barrio, JA Bartl, W Bates, MJ Battaglia, M Baubillier, M Baudot, J Becks, KH Begalli, M Beilliere, P Belokopytov, Y Belous, K Benvenuti, AC Berggren, M Bertrand, D Bianchi, F Bigi, M Bilenky, MS Billoir, P Bloch, D Blume, M Blyth, S Bolognese, T Bonesini, M Bonivento, W Booth, PSL Borisov, G Bosio, C Bosworth, S Botner, O Boudinov, E Bouquet, B Bourdarios, C Bowcock, TJV Bozzo, M Branchini, P Brand, KD Brenke, T Brenner, RA Bricman, C Brillault, L Brown, RCA Bruckman, P Brunet, JM Bugge, L Buran, T Burgsmueller, T Buschmann, P Buys, A Cabrera, S Caccia, M Calvi, M Rozas, AJC Camporesi, T Canale, V Canepa, M Cankocak, K Cao, F Carena, F Carroll, L Caso, C Gimenez, MVC Cattai, A Cavallo, FR Cerrito, L Chabaud, V Charpentier, P Chaussard, L Chauveau, J Checchia, P Chelkov, GA Chen, M Chierici, R Chilapnikov, P Chochula, P Chorowicz, V Cindro, V Collins, P Contreras, JL Contri, R Cortina, E Cosme, G Cossutti, F Crawley, HB Crennell, D Crosetti, G Maestro, JC Czellar, S DahlJensen, E Dahm, J Dalmagne, B Dam, M Damgaard, G Dauncey, PD Davenport, M DaSilva, W Defoix, C Deghorain, A DellaRicca, G Delpierre, P Demaria, N DeAngelis, A DeBoer, W DeBrabandere, S DeClercq, C DelaVaissiere, C DeLotto, B DeMin, A DePaula, L DeSaintJean, C Dijkstra, H DiCiaccio, L Djama, F Dolbeau, J Donszelmann, M Doroba, K Dracos, M Drees, J Drees, KA Dris, M Dufour, Y Edsall, D Ehret, R Eigen, G Ekelof, T Ekspong, G Elsing, M Engel, JP Ershaidat, N Erzen, B Santo, ME Falk, E Fassouliotis, D Feindt, M Fenyuk, A Ferrer, A Filippas, TA Firestone, A Fisher, PA Foeth, H Fokitis, E Fontanelli, F Formenti, F Franek, B Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R FuldaQuenzer, F Fuster, J Galloni, A Gamba, D Gandelman, M Garcia, C Garcia, J Gaspar, C Gasparini, U Gavillet, P Gazis, EN Gele, D Gerber, JP Gerdyukov, L Gibbs, M Gokieli, R Golob, B Gopal, G Gorn, L Gorski, M Gouz, Y Gracco, V Graziani, E Grosdidier, G Grzelak, K Gumenyuk, S Gunnarsson, P Gunther, M Guy, J Hahn, S Hajduk, Z Hallgren, A Hamacher, K Hao, W Harris, FJ Hedberg, V Henriques, R Hernandez, JJ Herquet, P Herr, H Hessing, TL Higon, E Hilke, HJ Hill, TS Holmgren, SO Holt, PJ Holthuizen, D Hoorelbeke, S Houlden, M Hrubec, J Huet, K Hultqvist, K Jackson, JN Jacobsson, R Jalocha, P Janik, R Jarlskog, C Jarlskog, G Jarry, P JeanMarie, B Johansson, EK Jonsson, L Jonsson, P Joram, C Juillot, P Kaiser, M Kapusta, F Karafasoulis, K Karlsson, M Karvelas, E Katsanevas, S Katsoufis, EC Keranen, R Khohklov, Y Khomenko, BA Khovanski, NN King, B Kjaer, NJ Klein, H Klovning, A Kluit, P Koene, B Kokkinias, P Koratzinos, M Korcyl, K Kourkoumelis, C Kouznetsov, O Kramer, PH Krammer, M Kreuter, C Kronkvist, I Krumstein, Z Krupinski, W Kubinec, P Kucewicz, W Kurvinen, K Lacasta, C Laktineh, I Lamblot, S Lamsa, JW Lanceri, L Lane, DW Langefeld, P Last, I Laugier, JP Lauhakangas, R Leder, G Ledroit, F Lefebure, V Legan, CK Leitner, R Lemoigne, Y Lemonne, J Lenzen, G Lepeltier, V Lesiak, T Liko, D Lindner, R Lipniacka, A Lippi, I Loerstad, B Lokajicek, M Loken, JG Lopez, JM Loukas, D Lutz, P Lyons, L MacNaughton, J Maehlum, G Maio, A Malychev, V Mandl, F Marco, J Marco, R Marechal, B Margoni, M Marin, JC Mariotti, C Markou, A Maron, T MartinezRivero, C MartinezVidal, F Garcia, SMI Matorras, F Matteuzzi, C Matthiae, G Mazzucato, M McCubbin, M McKay, R McNulty, R Medbo, J Merk, M Meroni, C Meyer, S Meyer, WT Michelotto, M Migliore, E Mirabito, L Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Mundim, LM Murray, WJ Muryn, B Myatt, G Naraghi, F Navarria, FL Navas, S Nawrocki, K Negri, P Nemecek, S Neumann, W Neumeister, N Nicolaidou, R Nielsen, BS Nieuwenhuizen, M Nikolaenko, V Niss, P Nomerotski, A Normand, A OberschulteBeckmann, W Obraztsov, V Olshevski, AG Onofre, A Orava, R Osterberg, K Ouraou, A Paganini, P Paganoni, M Pages, P Palka, H Papadopoulou, TD Papageorgiou, K Pape, L Parkes, C Parodi, F Passeri, A Pegoraro, M Peralta, L Pernegger, H Pernicka, M Perrotta, A Petridou, C Petrolini, A Petrovyck, M Podobrin, O Pol, ME Polok, G Poropat, P Pozdniakov, V Prest, M Privitera, P Pukhaeva, N Pullia, A Radojicic, D Ragazzi, S Rahmani, H Rames, J Ratoff, PN Read, AL Reale, M Rebecchi, P Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, J Ridky, J Rinaudo, G Ripp, I Romero, A Roncagliolo, I Ronchese, P Roos, L Rosenberg, EI Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W RuhlmannKleider, V Ruiz, A Rybicki, K Saarikko, H Sacquin, Y Sadovsky, A Sajot, G Salt, J Sanchez, J Sannino, M Schimmelpfennig, M Schneider, H Schwickerath, U Schyns, MAE Sciolla, G Scuri, F Seager, P Sedykh, Y Segar, AM Seitz, A Sekulin, R Shellard, RC Siccama, I Siegrist, P Simonetti, S Simonetto, F Sisakian, AN Sitar, B Skaali, TB Smadja, G Smirnov, N Smirnova, O Smith, GT Solovianov, O Sosnowski, R SouzaSantos, D Spiriti, E Sponholz, P Squarcia, S Stanescu, C Stapnes, S Stavitski, I Stichelbaut, F Stocchi, A Strauss, J Strub, R Stugu, B Szczekowski, M Szeptycka, M Tabarelli, T Tavernet, JP Tchikilev, O Tilquin, A Timmermans, J Tkatchev, LG Todorov, T Toet, DZ Tomaradze, A Tome, B Tonazzo, A Tortora, L Transtromer, G Treille, D Trischuk, W Tristram, G Trombini, A Troncon, C Tsirou, A Turluer, ML Tyapkin, IA Tyndel, M Tzamarias, S Ueberschaer, B Ullaland, O Uvarov, V Valenti, G Vallazza, E VanderVelde, C VanEldik, J Vassilopoulos, N Vegni, G Ventura, L Venus, W Verbeure, F Verlato, M Vertogradov, LS Vilanova, D Vincent, P Vitale, L Vlasov, E Vodopyanov, AS Vrba, V Wahlen, H Walck, C Waldner, F Weierstall, M Weilhammer, P Weiser, C Wetherell, AM Wicke, D Wickens, JH Wielers, M Wilkinson, GR Williams, WSC Winter, M Witek, M Woschnagg, K Yip, K Yuschenko, O Zach, F Zaitsev, A Zalewska, A Zalewski, P Zavrtanik, D Zevgolatakos, E Zimin, NI Zito, M Zontar, D Zuberi, R Zucchelli, GC Zumerle, G TI Charged particle multiplicity in e(+)e(-) interactions at root s=130 GeV SO PHYSICS LETTERS B LA English DT Article AB From the data collected by DELPHI at LEP in autumn 1995, the multiplicity of charged particles at a hadronic energy of 130 GeV has been measured to be [n(ch)] = 23.84 +/- 0.51(stat) +/- 0.52(syst), When compared to lower energy data, the value measured is consistent with the evolution predicted by QCD with corrections at next-to-leading order, for a value alpha(s) (130 GeV) = 0.105 +/- 0.003(stat) +/- 0.008(syst). C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. UNIV INSTELLING ANTWERP,DEPT PHYS,B-2610 WILRIJK,BELGIUM. FREE UNIV BRUSSELS,IIHE,B-1050 BRUSSELS,BELGIUM. UNIV MONS,FAC SCI,B-7000 MONS,BELGIUM. UNIV ATHENS,PHYS LAB,GR-10680 ATHENS,GREECE. UNIV BERGEN,DEPT PHYS,N-5007 BERGEN,NORWAY. UNIV BOLOGNA,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. CTR BRASILEIRO PESQUISAS FIS,BR-22290 RIO JANEIRO,BRAZIL. PONTIFICIA UNIV CATOLICA RIO DE JANEIRO,DEPT FIS,BR-22453 RIO JANEIRO,BRAZIL. UNIV ESTADUAL RIO DE JANEIRO,INST FIS,RIO JANEIRO,BRAZIL. COMENIUS UNIV BRATISLAVA,FAC MATH & PHYS,BRATISLAVA 84215,SLOVAKIA. COLL FRANCE,PHYS CORPUSCULAIRE LAB,IN2P3,CNRS,F-75231 PARIS 05,FRANCE. CERN,CH-1211 GENEVA 23,SWITZERLAND. UNIV STRASBOURG 1,CNRS,IN2P3,CTR RECH NUCL,F-67037 STRASBOURG,FRANCE. NCSR DEMOKRITOS,INST NUCL PHYS,GR-15310 ATHENS,GREECE. 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UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. IST NAZL FIS NUCL,I-20133 MILAN,ITALY. NIELS BOHR INST,DK-2100 COPENHAGEN 0,DENMARK. CHARLES UNIV,MFF,NUCL CTR,CR-18000 PRAGUE 8,CZECH REPUBLIC. NIKHEF H,1009 DB AMSTERDAM,NETHERLANDS. NATL TECH UNIV ATHENS,DEPT PHYS,GR-15773 ATHENS,GREECE. UNIV OSLO,DEPT PHYS,N-1000 OSLO 3,NORWAY. UNIV OVIEDO,DEPT FIS,E-33006 OVIEDO,SPAIN. UNIV OXFORD,DEPT PHYS,OXFORD OX1 3RH,ENGLAND. UNIV PADUA,DIPARTIMENTO FIS,I-35131 PADUA,ITALY. IST NAZL FIS NUCL,I-35131 PADUA,ITALY. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,I-00173 ROME,ITALY. IST NAZL FIS NUCL,I-00173 ROME,ITALY. UC,CSIC,INST FIS CANTABRIA,CICYT,E-39006 SANTANDER,SPAIN. INST HIGH ENERGY PHYS,PROTVINO,RUSSIA. UNIV LJUBLJANA,JOZEF STEFAN INST,LJUBLJANA 61000,SLOVENIA. UNIV LJUBLJANA,DEPT PHYS,LJUBLJANA 61000,SLOVENIA. UNIV STOCKHOLM,S-11385 STOCKHOLM,SWEDEN. UNIV TURIN,DIPARTIMENTO FIS SPERIMENTALE,I-10125 TURIN,ITALY. IST NAZL FIS NUCL,I-10125 TURIN,ITALY. UNIV TRIESTE,DIPARTIMENTO FIS,I-34127 TRIESTE,ITALY. IST NAZL FIS NUCL,I-34127 TRIESTE,ITALY. UNIV UDINE,IST FIS,I-33100 UDINE,ITALY. FED UNIV RIO DE JANEIRO,BR-21945970 RIO JANEIRO,BRAZIL. UPPSALA UNIV,DEPT RADIAT SCI,S-75121 UPPSALA,SWEDEN. UNIV VALENCIA,IFIC,CSIC,E-46100 BURJASSOT,SPAIN. UNIV VALENCIA,DFAMN,E-46100 BURJASSOT,SPAIN. AUSTRIAN ACAD SCI,INST HOCHENERGIEPHYS,A-1050 VIENNA,AUSTRIA. INST NUCL STUDIES,PL-00681 WARSAW,POLAND. UNIV WARSAW,PL-00681 WARSAW,POLAND. UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH PHYS,D-42097 WUPPERTAL 1,GERMANY. CENS,DSM,DAPNIA,F-91191 GIF SUR YVETTE,FRANCE. IST NAZL FIS NUCL,IST SUPER SANITA,I-00161 ROME,ITALY. RP Abreu, P (reprint author), FCUL,IST,LIP,AV ELIAS GARCIA 14-1 O,P-1000 LISBON,PORTUGAL. RI Abreu, Pedro/L-2220-2014; Navas, Sergio/N-4649-2014; Barao, Fernando/O-2357-2016; Barrio, Juan/L-3227-2014; Zaitsev, Alexandre/B-8989-2017; gandelman, miriam/N-3739-2014; Ragazzi, Stefano/D-2463-2009; Cabrera Urban, Susana/H-1376-2015; Matorras, Francisco/I-4983-2015; Ferrer, Antonio/H-2942-2015; Rovelli, Tiziano/K-4432-2015; Smirnova, Oxana/A-4401-2013; Della Ricca, Giuseppe/B-6826-2013; Olshevskiy, Alexander/I-1580-2016; Rames, Jiri/H-2450-2014; Paganoni, Marco/A-4235-2016; Contreras Gonzalez, Jose Luis/K-7255-2014; Hallgren, Allan/A-8963-2013; Botner, Olga/A-9110-2013; Michelotto, Michele/A-9571-2013; Mundim, Luiz/A-1291-2012; Zalewski, Piotr/H-7335-2013; Marti-Garcia, Salvador/F-3085-2011; Monge, Maria Roberta/G-9127-2012; Nemecek, Stanislav/G-5931-2014; Ridky, Jan/H-6184-2014; Tome, Bernardo/J-4410-2013; Fernandez, Ester/K-9734-2014; Espirito Santo, Maria Catarina/L-2341-2014; Nomerotski, Andrei/A-5169-2010; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; branchini, paolo/A-4857-2011; Krammer, Manfred/A-6508-2010; De Saint Jean, Cyrille/E-8853-2011; Shellard, Ronald/G-4825-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-2012; Andreazza, Attilio/E-5642-2011; Verlato, Marco/J-4604-2012; Dracos, Marcos/K-2335-2012 OI Abreu, Pedro/0000-0002-9973-7314; Navas, Sergio/0000-0003-1688-5758; Barao, Fernando/0000-0002-8346-9941; Barrio, Juan/0000-0002-0965-0259; Zaitsev, Alexandre/0000-0002-4961-8368; Ragazzi, Stefano/0000-0001-8219-2074; Matorras, Francisco/0000-0003-4295-5668; Ferrer, Antonio/0000-0003-0532-711X; Rovelli, Tiziano/0000-0002-9746-4842; Smirnova, Oxana/0000-0003-2517-531X; Della Ricca, Giuseppe/0000-0003-2831-6982; Olshevskiy, Alexander/0000-0002-8902-1793; Paganoni, Marco/0000-0003-2461-275X; Contreras Gonzalez, Jose Luis/0000-0001-7282-2394; Michelotto, Michele/0000-0001-6644-987X; Mundim, Luiz/0000-0001-9964-7805; Monge, Maria Roberta/0000-0003-1633-3195; Ridky, Jan/0000-0001-6697-1393; Tome, Bernardo/0000-0002-7564-8392; Espirito Santo, Maria Catarina/0000-0003-1286-7288; Ruiz, Alberto/0000-0002-3639-0368; Krammer, Manfred/0000-0003-2257-7751; Shellard, Ronald/0000-0002-2983-1815; Petrolini, Alessandro/0000-0003-0222-7594; Andreazza, Attilio/0000-0001-5161-5759; Verlato, Marco/0000-0003-1967-7655; Dracos, Marcos/0000-0003-0514-193X NR 15 TC 44 Z9 44 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 4 PY 1996 VL 372 IS 1-2 BP 172 EP 180 DI 10.1016/0370-2693(96)00134-7 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA UE454 UT WOS:A1996UE45400027 ER PT J AU Shin, W Sundaram, UM Cole, JL Zhang, HH Hedman, B Hodgson, KO Solomon, EI AF Shin, W Sundaram, UM Cole, JL Zhang, HH Hedman, B Hodgson, KO Solomon, EI TI Chemical and spectroscopic definition of the peroxide-level intermediate in the multicopper oxidases: Relevance to the catalytic mechanism of dioxygen reduction to water SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID X-RAY ABSORPTION; RHUS-VERNICIFERA LACCASE; COPPER ACTIVE-SITE; MAGNETIC CIRCULAR-DICHROISM; ELECTRONIC-STRUCTURE; ASCORBATE OXIDASE; NATIVE LACCASE; CRYSTAL-STRUCTURE; FINE-STRUCTURE; REACTIVITY AB Laccase is a multicopper oxidase which contains four coppers, one type 1, one type 2, and a coupled binuclear type 3 pair, the type 2 and type 3 copper centers together forming a trinuclear copper cluster. The type 1 mercury derivative of laccase (T1Hg Lc) has the type 1 center substituted with a redox inactive Hg2+ ion and an intact trinuclear copper cluster. Reaction of reduced T1Hg Lc with dioxygen produces an oxygen intermediate which has now been studied in detail. Isotope ratio mass spectrometry (IRMS) has shown that both oxygen atoms of O-2 are bound in the intermediate. EPR and SQUID magnetic susceptibility studies have shown that the intermediate is diamagnetic. The results combined with X-ray absorption edge data indicate that the intermediate contains a bound peroxide and that the two electrons have derived from the type 3 center which is antiferromagnetically coupled. EXAFS data show that there is no short Cu-oxo bond in the intermediate and that there is a new bridging interaction in the intermediate, with two coppers being separated by 3.4 Angstrom, that is not present in the resting enzyme. Circular dichroism (CD) and magnetic circular dichroism (MCD) studies in the ligand field region confirm that the two type 3 coppers are oxidized and antiferromagnetically coupled and that the type 2 copper is reduced. In addition, the charge transfer (CT) absorption spectrum of the intermediate supports a mu-1, 1 hydroperoxide description based on a comparison to Cu(II)-peroxo model spectra. The decay of the T1Hg Lc oxygen intermediate is pH dependent, slow, and proceeds through an additional intermediate with an MCD spectrum in the CT region analogous to that of the oxygen intermediate in the native enzyme which is at least one electron further reduced. These studies lead to a spectroscopically effective model for peroxide bound to the trinuclear copper cluster site in the intermediate, and provide significant insight into the molecular mechanism of the catalytic reduction of dioxygen to water by the multicopper oxidases. C1 STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94305. RI Cole, James/G-2586-2011 NR 64 TC 101 Z9 105 U1 4 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 3 PY 1996 VL 118 IS 13 BP 3202 EP 3215 DI 10.1021/ja953621e PG 14 WC Chemistry, Multidisciplinary SC Chemistry GA UD464 UT WOS:A1996UD46400015 ER PT J AU Hu, J Wang, M Weier, HUG Frantz, P Kolbe, W Ogletree, DF Salmeron, M AF Hu, J Wang, M Weier, HUG Frantz, P Kolbe, W Ogletree, DF Salmeron, M TI Imaging of single extended DNA molecules on flat (aminopropyl)triethoxysilane-mica by atomic force microscopy SO LANGMUIR LA English DT Letter AB Long strands of DNA have been deposited, extended, and immobilized on chemically modified mica for study with an atomic force microscope (AFM). By employing a modified ''molecular combing'' technique and carefully silanized mica, we show that DNA molecules may be distributed uniformly, adsorbed in extended conformations, and bound with great tenacity. When maintained in a buffer solution, these strands remained stable for > 5 h. Scanning the surface with high loads applied to an AFM tip induced fragmentation in the strands, but remaining pieces never relinquished their original positions. Further imaging applications, such as after treatment of the DNA by molecular hybridization or DNA synthesis and labeling in situ, are discussed. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,ELECT ENGN DIV,BERKELEY,CA 94720. ACAD SINICA,SHANGHAI INST NUCL RES,SHANGHAI 201800,PEOPLES R CHINA. NR 13 TC 98 Z9 111 U1 1 U2 26 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 3 PY 1996 VL 12 IS 7 BP 1697 EP 1700 DI 10.1021/la950874c PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA UD794 UT WOS:A1996UD79400001 ER PT J AU Fagan, PA Fabrega, C Eritja, R Goodman, MF Wemmer, DE AF Fagan, PA Fabrega, C Eritja, R Goodman, MF Wemmer, DE TI NMR study of the conformation of the 2-aminopurine:cytosine mismatch in DNA SO BIOCHEMISTRY LA English DT Article ID BASE-PAIRS; POLYMERASE INSERTION; TRANSITION MUTATIONS; KLENOW FRAGMENT; MOLECULAR-BASIS; FIDELITY; SPECTROSCOPY; MISPAIRS; ADENINE; INVITRO AB DNA polymerase makes errors by misincorporating natural DNA bases and base analogs. Because of the wide variety of possible mismatches and the varying efficiency with which they are repaired, structural studies are necessary to understand in detail how these mispairs differ and can be distinguished from standard Watson-Crick base pairs. 2-Aminopurine (AP) is a highly mutagenic base analog. The objective of this study was to determine the geometry of the AP . C mispair in DNA at neutral pH. Although several studies have focused on the AP . C mispair in DNA, there is not as of yet consensus on its structure. At least four models have been proposed for this mispair. Through the use of NMR spectroscopy with selective N-15-labeling of exocyclic amino nitrogens on bases of interest, we are able to resolve ambiguities in previous studies. We find here that, in two different DNA sequences, the AP . C mispair at neutral and high pH is in a wobble geometry. The structure and stability of this base mispair is dependent upon the local base sequence. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. EUROPEAN MOLEC BIOL LAB,D-69117 HEIDELBERG,GERMANY. UNIV SO CALIF,HEDCO MOLEC BIOL LABS,DEPT BIOL SCI,LOS ANGELES,CA 90089. RI eritja, ramon/B-5613-2008; Fabrega, MCarme/K-9847-2014 OI eritja, ramon/0000-0001-5383-9334; Fabrega, MCarme/0000-0003-3816-7634 FU NIGMS NIH HHS [GM21422, GM42554] NR 47 TC 51 Z9 52 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 2 PY 1996 VL 35 IS 13 BP 4026 EP 4033 DI 10.1021/bi952657g PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UC977 UT WOS:A1996UC97700021 PM 8672436 ER PT J AU deAzevedo, WF MuellerDieckmann, HJ SchulzeGahmen, U Worland, PJ Sausville, E Kim, SH AF deAzevedo, WF MuellerDieckmann, HJ SchulzeGahmen, U Worland, PJ Sausville, E Kim, SH TI Structural basis for specificity and potency of a flavonoid inhibitor of human CDK2, a cell cycle kinase SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE cyclin-dependent kinase; protein kinase inhibitors; cancer; drug design; flavopiridol ID CATALYTIC SUBUNIT; PROTEIN-KINASE; DEPENDENT KINASE-2; CRYSTAL-STRUCTURE; CRYSTALLIZATION; P21 AB The central role of cyclin-dependent kinases (CDKs) in cell cycle regulation makes them a promising target for studying inhibitory molecules that can modify the degree of cell proliferation, The discovery of specific inhibitors of CDKs such as polyhydroxylated flavones has opened the way to investigation and design of antimitotic compounds, A novel flavone, (-)-cis-5,7-dihydroxyphenyl-8-[4-(3-hydroxy-1-methyl)piperidinyl]-4H-1-benzopyran-4-one hydrochloride hemihydrate (L868276), is a potent inhibitor of CDKs. A chlorinated form, flavopiridol, is currently in phase I clinical trials as a drug against breast tumors, We determined the crystal structure of a complex between CDK2 and L868276 at 2.33-Angstrom resolution and refined to an R(factor) of 20.3%. The aromatic portion of the inhibitor binds to the adenine-binding pocket of CDK2, and the position of the phenyl group of the inhibitor enables the inhibitor to make contacts with the enzyme not observed in the ATP complex structure, The analysis of the position of this phenyl ring not only explains the great differences of kinase inhibition among the flavonoid inhibitors but also explains the specificity of L868276 to inhibit CDK2 and CDC2. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NCI,DIV CANC TREATMENT,BIOL CHEM LAB,DEV THERAPEUT PROGRAM,BETHESDA,MD 20892. NR 36 TC 328 Z9 333 U1 1 U2 11 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 APR 2 PY 1996 VL 93 IS 7 BP 2735 EP 2740 DI 10.1073/pnas.93.7.2735 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA UD375 UT WOS:A1996UD37500021 PM 8610110 ER PT J AU Luo, JQ Ruble, JR Craven, BM McMullan, RK AF Luo, JQ Ruble, JR Craven, BM McMullan, RK TI Effects of H/D substitution on thermal vibrations in piperazinium hexanoate-h(11),d(11) SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID ALIPHATIC CHAINS; DIFFRACTION AB The crystal structures of piperazinium hexanoate-h(11), 1/2C(4)H(12)N(2)(2+).C6H11O2-, and piperazinium hexanoated(11), d(11), 1/2C(2)N(2)(2+).C6D11O2-, have been determined from neutron diffraction data collected at 15 K. Nuclear anisotropic displacement parameters have been analyzed to obtain the internal molecular displacements of the H and D nuclei, given by [u(obs)(2)] - [u(ext)(2)] where [u(ext)(2)] is the contribution assuming all H/D to be carried rigidly on the vibrating molecular framework consisting of the heavier nuclei. In both crystal structures the cation ring is well fitted by the rigid-body model and the anion chain by a model with two rigid segments. In the piperazinium cations the corresponding protons in the two structures have about the same internal vibrational directions and magnitudes except for the two N-H protons, perhaps owing to differences in N-H ... O hydrogen bonding. The internal vibrations of corresponding H/D in the h(11) and d(11) anions have approximately the same vibrational directions. The internal mean-square displacements of the H nuclei are systematically greater than the values of the corresponding D nuclei by an average factor 1.7(3). For both anions, normal-mode analyses have been carried out using the force fields derived from ab initio quantum-mechanical calculations with HF/3-21G and HF/6-31G** basis sets. The values of the resultant H/D internal displacements for C-H(D) bond stretching and methylene out-of-plane vibrations are in good agreement with experiment. However, with either basis set, theory predicts methylene in-plane mean-square displacements significantly greater than the experimental values. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP Luo, JQ (reprint author), UNIV PITTSBURGH,DEPT CRYSTALLOG,PITTSBURGH,PA 15260, USA. FU NCRR NIH HHS [1P41RR06009]; NHLBI NIH HHS [HL-20350]; NIGMS NIH HHS [GM-22548] NR 39 TC 10 Z9 10 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Commun. PD APR 1 PY 1996 VL 52 BP 357 EP 368 DI 10.1107/S0108768195011025 PN 2 PG 12 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA UK561 UT WOS:A1996UK56100019 PM 8624243 ER PT J AU Rittner, MN Weertman, JR Eastman, JA AF Rittner, MN Weertman, JR Eastman, JA TI Structure-property correlations in nanocrystalline Al-Zr alloy composites SO ACTA MATERIALIA LA English DT Article ID NANOMETER-SIZED CRYSTALS; MECHANICAL-PROPERTIES; BEHAVIOR; TEM; MICROSTRUCTURE; NICKEL AB A study of the structure, grain size stability and Vickers microhardness of nanocrystalline aluminum-zirconium alloy composites was conducted. Samples were synthesized by the inert gas condensation process with electron beam evaporation. Transmission electron microscope examinations of the samples were performed at room and elevated temperatures. The behavior of the microstructures of the samples with time and temperature was investigated as a function of specimen composition. Vickers microhardness data were evaluated at room temperature in as-produced and polished compacted specimens. The local chemical composition of individual microhardness indents and average values of the grain size and porosity level were determined for a number of samples. Correlations among these microstructural variables and hardness were determined using multiple regression techniques. C1 ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RP NORTHWESTERN UNIV, DEPT MAT SCI & ENGN, EVANSTON, IL 60208 USA. RI Weertman, Julia/B-7540-2009; Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 49 TC 15 Z9 15 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD APR PY 1996 VL 44 IS 4 BP 1271 EP 1286 DI 10.1016/1359-6454(95)00303-7 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UD265 UT WOS:A1996UD26500001 ER PT J AU Mecking, H Hartig, C Kocks, UF AF Mecking, H Hartig, C Kocks, UF TI Deformation modes in gamma-TiAl as derived from the single crystal yield surface SO ACTA MATERIALIA LA English DT Article ID BEHAVIOR AB Based on a detailed analysis of the topography of the single crystal yield surface, a deformation mode map for slip and twinning of Ll(o) ordered gamma-TiAl is derived. Various different deformation systems have been considered, namely, glide of ordinary and superdislocations as well as shear contributions by ordered twins. In the framework of the Taylor model for all combinations of critical resolved shear stress, parameters for polycrystal deformation are determined such as Taylor factors, slip distribution among the various deformation modes and internal stresses set up between grains. The comparison of theoretical with experimental textures, and of predicted with observed anisotropy of plastic how, is utilized to determine the slip geometry and the relative strength levels of the different deformation systems. The results are used for a general discussion of deformation processes observed in TiAl and how these are affected by work hardening characteristics. It is concluded that superdislocations of one kind or another are necessary deformation modes, and that all modes have similar CRSS values at large strains. C1 LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP Mecking, H (reprint author), TECH UNIV HAMBURG,D-21073 HAMBURG,GERMANY. RI Hartig, Christian/F-4673-2010; Kocks, Fred/E-1159-2011 NR 33 TC 62 Z9 62 U1 1 U2 17 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR PY 1996 VL 44 IS 4 BP 1309 EP 1321 DI 10.1016/1359-6454(95)00308-8 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UD265 UT WOS:A1996UD26500004 ER PT J AU Fu, CL Zou, J AF Fu, CL Zou, J TI Site preference of ternary alloying additions in FeAl and NiAl by first-principles calculations SO ACTA MATERIALIA LA English DT Article ID TENSILE AB First-principles calculations have been performed to investigate the site preference of ternary alloying additions in FeAl and NiAl. In FeAl, Cr and Ti are found to occupy the Al sublattice whereas Ni has a distinct preference for the Fe sublattice. The site substitutional behavior of 3d ternary elements in FeAl can be explained in terms of the trends in the heat-of-formation. In Al-rich NiAl, Fe atoms occupy exclusively the Ni sublattice. In Ni-rich NiAl, because of the small enthalpy difference between Fe occupying Al and Ni sublattices (i.e. less than 0.1 eV with a preference of Fe for Al sites at O K), the site distributions of Fe in these alloys are found to vary with alloy composition and temperature. Due to the large difference in the local magnetic moments between Fe atoms occupying Al and Ni sublattices (with values of 2.4 mu(B) and less than 0.1 mu(B), respectively) in NiAl, magnetic susceptibility measurement should be the most effective way to measure the site distributions of Fe in NiAl. RP Fu, CL (reprint author), OAK RIDGE NATL LAB, DIV MET & CERAM, POB 2008, OAK RIDGE, TN 37831 USA. NR 18 TC 80 Z9 81 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD APR PY 1996 VL 44 IS 4 BP 1471 EP 1478 DI 10.1016/1359-6454(95)00297-9 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UD265 UT WOS:A1996UD26500015 ER PT J AU Wang, JN AF Wang, JN TI A new modification of the formulation of peierls stress SO ACTA MATERIALIA LA English DT Article AB The classical derivation of Peierls stress is critically examined. It is found that in Peierls-Nabbaro treatments there may exist an error in representing the atom positions across the slip plane after the dislocation is assumed to be translated by a distance. With the correction of this error, it is shown that the misfit energy of the dislocation and the lattice friction to dislocation motion have an expected periodicity of the Burgers vector b rather than the unexpected periodicity of b/2 predicted by the original model. Under the new representations of atom positions, it is also shown that the Peierls stress formula for a dislocation in a lattice in which atoms just above and below the slip plane face each other may not be different from that for a dislocation in a lattice in which atoms alternate across the slip plane, as suggested before. RP Wang, JN (reprint author), LAWRENCE LIVERMORE NATL LAB,L-370,POB 808,LIVERMORE,CA 94551, USA. NR 15 TC 36 Z9 36 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD APR PY 1996 VL 44 IS 4 BP 1541 EP 1546 DI 10.1016/1359-6454(95)00273-1 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UD265 UT WOS:A1996UD26500021 ER PT J AU Rodenberg, R AF Rodenberg, R TI Top Higgs SO ACTA PHYSICA POLONICA B LA English DT Article ID VACUUM STABILITY; BOSON MASSES; FIXED-POINTS; MIXING ANGLE; SUPERSYMMETRY; SUPERGRAVITY; MODELS; PREDICTIONS; UNIFICATION; SUPERFIELD AB For m(top) > 150 GeV there exists an (m(top), m(Higgs))-area in which both the SM and the MSSM are excluded. But the requirement of vacuum stability in a 2-Higgs model fits into this region. With supersymmetric SU(5) one can overcome by part the socalled hierarchy problem. Further, SU(5) and SO(10) supersymmetric GUT models with fixed point solutions and non-linear realizations of SUSY belong also to this area. Finally one can show that the SM originates from its minimal supersymmetric extension which is explicitely broken due to soft SUSY breaking terms at scale M(SUSY), and that the NMSSM has roughly no influence on the previous predictions. So far the discovery of Top at FNAL ''localizes'' Higgs. RP Rodenberg, R (reprint author), FERMILAB NATL ACCELERATOR LAB,DEPT THEORET PHYS,POB 500,BATAVIA,IL 60510, USA. NR 49 TC 0 Z9 0 U1 0 U2 0 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, 02-668 WARSAW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD APR PY 1996 VL 27 IS 4 BP 865 EP 879 PG 15 WC Physics, Multidisciplinary SC Physics GA UG400 UT WOS:A1996UG40000005 ER PT J AU Brow, RK AF Brow, RK TI Precollege science education: Start them early SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article RP Brow, RK (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, 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 APR PY 1996 VL 75 IS 4 BP 69 EP 70 PG 2 WC Materials Science, Ceramics SC Materials Science GA UE403 UT WOS:A1996UE40300008 ER PT J AU Bharathan, G AF Bharathan, G TI Reproductive development and nuclear DNA content in angiosperms SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE cell cycle; cytoskeleton; dicotyledons; endosperm development; megasporogenesis; microsporogenesis; monocotyledons; nuclear DNA content; phylogenetic relationships; reproductive development ID C-VALUE PARADOX; GENOME SIZE; SYSTEMATIC EMBRYOLOGY; F-ACTIN; HERBACEOUS ANGIOSPERMS; POLLEN DEVELOPMENT; HIGHER-PLANTS; CELL-VOLUME; EVOLUTION; ORGANIZATION AB Correlates of nuclear DNA content in angiosperms have been noted previously for a range of features, cellular to geographic. A new hypothesis, the correlation between nuclear DNA content and reproductive developmental features (after Cavalier-Smith, Journal of Cell Science 34, 247-268, 1978) is posed and tested here. Of three features tested (megasporogenesis, microsporogenesis, and endosperm development), megasporogenesis alone was shown to be correlated with nuclear DNA amount. The hypothesis was examined in 107 families of angiosperms using nonparametric statistics, and in 53 families of monocotyledons and outgroups using a phylogenetic test of association. A correlation was found between large genomes and successive microsporogenesis for all angiosperms, but not for monocots and dicots analyzed separately, thus underlining the importance of taking into account phylogenetic relationships in such studies. A correlation between cellular endosperm and large genomes in dicotyledons needs to be confirmed in a phylogenetic context. A tendency for deviations from monosporic megasporogenesis to occur in taxa that have a nuclear DNA content of over 9.0 pg/C was demonstrated using both phylogenetic and nonphylogenetic tests. It is hypothesized that cytoskeleton dynamics are affected in reproductive cells, enabling decoupling between nuclear and cytoplasmic cell cycles and lending to variation in reproductive development. RP Bharathan, G (reprint author), LAWRENCE LIVERMORE NATL LAB,DEPT AGRON & RANGE SCI,DAVIS,CA 95616, USA. NR 88 TC 20 Z9 21 U1 0 U2 1 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY 1735 NEIL AVE, COLUMBUS, OH 43210 SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD APR PY 1996 VL 83 IS 4 BP 440 EP 451 DI 10.2307/2446213 PG 12 WC Plant Sciences SC Plant Sciences GA UH186 UT WOS:A1996UH18600004 ER PT J AU Lovely, RH Buschbom, RL Slavich, AL Anderson, LE Hansen, NH Wilson, BW AF Lovely, RH Buschbom, RL Slavich, AL Anderson, LE Hansen, NH Wilson, BW TI Adult leukemia risk and personal appliance use: A preliminary study. Reply SO AMERICAN JOURNAL OF EPIDEMIOLOGY LA English DT Letter RP Lovely, RH (reprint author), BATTELLE SEATTLE RES CTR,SEATTLE,WA 98105, USA. NR 7 TC 0 Z9 1 U1 0 U2 0 PU AMER J EPIDEMIOLOGY PI BALTIMORE PA 624 N BROADWAY RM 225, BALTIMORE, MD 21205 SN 0002-9262 J9 AM J EPIDEMIOL JI Am. J. Epidemiol. PD APR 1 PY 1996 VL 143 IS 7 BP 744 EP 745 PG 2 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA UD948 UT WOS:A1996UD94800014 ER PT J AU Robinett, RW AF Robinett, RW TI Visualizing the solutions for the circular infinite well in quantum and classical mechanics SO AMERICAN JOURNAL OF PHYSICS LA English DT Article AB The classical and quantum mechanical problem of a particle in the infinite circular well has recently surfaced in two quite different manifestations: (i) the observation of ''electron standing waves'' in circular ''corrals'' of atoms adsorbed on surfaces and (ii) as a benchmark example of an integrable system for comparison to the classical and quantum chaotic behavior of the ''stadium billiards'' problem. Motivated by this, we review the quantum and classical probability distributions for both position and momentum for this familiar problem, focusing on,the visualization of the quantum wave functions and classical trajectories as well as the semiclassical connections between the two. (C) 1996 American Association of Physics Teachers. C1 PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. RP Robinett, RW (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439, USA. NR 10 TC 28 Z9 29 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD APR PY 1996 VL 64 IS 4 BP 440 EP 446 DI 10.1119/1.18188 PG 7 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA UA998 UT WOS:A1996UA99800016 ER PT J AU Smith, AB Chiba, S AF Smith, AB Chiba, S TI Neutron scattering from elemental uranium and thorium SO ANNALS OF NUCLEAR ENERGY LA English DT Article AB Differential neutron-scattering cross sections of elemental uranium and thorium are measured from approximate to 4.5 to 10.0 MeV in steps of approximate to 0.5 MeV. Forty or more differential values are obtained at each incident energy, distributed between approximate to 17 and 160 degrees. Scattered-neutron resolutions are defined to encompass contributions from the first four members of the ground-state rotational band (0(+) g.s., 2(+), 4(+) and 6(+) states). The experimental results are interpreted in the context of coupled-channels rotational models, and comparisons made with the respective ENDF/B-VI evaluated files. These comparisons suggest some modifications of the ENDF/B-VI U-238 and Th-232 evaluations. C1 UNIV ARIZONA,TUCSON,AZ. JAPAN ATOM ENERGY RES INST,TOKAI,IBARAKI 31911,JAPAN. RP Smith, AB (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 27 TC 17 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0306-4549 J9 ANN NUCL ENERGY JI Ann. Nucl. Energy PD APR PY 1996 VL 23 IS 6 BP 459 EP 467 DI 10.1016/0306-4549(95)00028-3 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA TT646 UT WOS:A1996TT64600001 ER PT J AU Kim, E Aversano, PJ Romine, MF Schneider, RP Zylstra, GJ AF Kim, E Aversano, PJ Romine, MF Schneider, RP Zylstra, GJ TI Homology between genes for aromatic hydrocarbon degradation in surface and deep-subsurface Sphingomonas strains SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID PSEUDOMONAS-PAUCIMOBILIS; NAPHTHALENE; BIPHENYL; TOLUENE; CATABOLISM; BACTERIA; DIVERSITY; SEDIMENTS AB The cloned genes for aromatic hydrocarbon degradation from Sphingomonas yanoikuyae B1 were utilized in Southern hybridization experiments with Sphingomonas strains from the surface and deep-subsurface environments. One hybridization pattern was obtained with BamHI-digested genomic DNAs for two surface strains, while a differing pattern was seen for five deep-subsurface strains. The cross-hybridizing genes were located in the chromosomes of the surface strains and on plasmids in the deep-subsurface strains. C1 RUTGERS STATE UNIV, CTR AGR MOLEC BIOL, COOK COLL, NEW BRUNSWICK, NJ 08903 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 31 TC 48 Z9 51 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD APR PY 1996 VL 62 IS 4 BP 1467 EP 1470 PG 4 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA UD950 UT WOS:A1996UD95000057 PM 8919814 ER PT J AU Devine, KD Flaherty, JE AF Devine, KD Flaherty, JE TI Parallel adaptive hp-refinement techniques for conservation laws SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID FINITE-ELEMENT METHOD; SYSTEMS; SCHEMES AB We describe an adaptive hp-refinement local finite element procedure for the parallel solution of hyperbolic systems of conservation laws on rectangular domains. The local finite element procedure utilizes spaces of piecewise-continuous polynomials of arbitrary degree and coordinated explicit Runge-Kutta temporal integration. A solution limiting procedure produces monotonic solutions near discontinuities while maintaining high-order accuracy near smooth extrema. A modified tiling procedure maintains processor load balance on parallel, distributed-memory MIMD computers by migrating finite elements between processors in overlapping neighborhoods to produce locally balanced computations. Grids are stored in tree data structures, with finer grids being offspring of coarser ones. Within each grid, AVL trees simplify the transfer of information between neighboring processors and the insertion and deletion of elements as they migrate between processors. Computations involving Burgers' and Euler's equations of inviscid flow demonstrate the effectiveness of the hp-refinement and balancing procedures relative to non-balanced adaptive and balanced non-adaptive procedures. C1 RENSSELAER POLYTECH INST,DEPT COMP SCI,TROY,NY 12180. RENSSELAER POLYTECH INST,SCI COMP RES CTR,TROY,NY 12180. RP Devine, KD (reprint author), SANDIA NATL LABS,PARALLEL COMP SCI DEPT,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 25 TC 48 Z9 49 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD APR PY 1996 VL 20 IS 4 BP 367 EP 386 DI 10.1016/0168-9274(95)00103-4 PG 20 WC Mathematics, Applied SC Mathematics GA UT823 UT WOS:A1996UT82300005 ER PT J AU Maya, L AF Maya, L TI Boron nitride precursors - A perspective SO APPLIED ORGANOMETALLIC CHEMISTRY LA English DT Review DE boron nitride; pyrolysis; chemical vapor deposition; aminoborane; borazine ID CYANOBORANE; DEPOSITION; CHEMISTRY; POLYMERS; BINDER AB Research efforts conducted in the Chemistry Division of the Oak Ridge National Laboratory on the preparation of polymeric precursors to boron nitride are reviewed, They evolved from the preparation of powders, which contained significant amounts of residual carbon, derived from the pyrolysis of aminoborane polymers to relatively pure films produced by chemical vapor deposition using polymeric cyanoborane as a single source, Interesting C/B/N films were produced from the pyrolyses of volatile borazine derivatives, and a polymeric borazine intermediate produced denser boron nitride (BN) compact bodies when used as a binder as opposed to bulk BN compressed without a binder, The challenges of producing boron nitride fibers have been defined. RP Maya, L (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,POB 2008,OAK RIDGE,TN 37831, USA. NR 18 TC 5 Z9 6 U1 4 U2 13 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0268-2605 J9 APPL ORGANOMET CHEM JI Appl. Organomet. Chem. PD APR-MAY PY 1996 VL 10 IS 3-4 BP 175 EP 182 DI 10.1002/(SICI)1099-0739(199604)10:3/4<175::AID-AOC464>3.0.CO;2-C PG 8 WC Chemistry, Applied; Chemistry, Inorganic & Nuclear SC Chemistry GA UH668 UT WOS:A1996UH66800003 ER PT J AU Danehy, PM Farrow, RL AF Danehy, PM Farrow, RL TI Gas-phase velocimetry by nearly degenerate four-wave mixing SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID SUPERSONIC FLOWS; TEMPERATURE; VELOCITY; SCATTERING AB We demonstrate a new velocimetry technique for gas flows based on Nearly Degenerate Four-Wave Mixing (NDFWM). Measurements were pet-formed on nitric oxide in a free-jet expansion using helium and argon as carrier gases, at flow velocities on the order of 1000 m/s. We obtained velocities by analyzing experimental spectra from the jet using a perturbative treatment of NDFWM that we extended to include an arbitrary bulk velocity. The results agreed with independent velocity measurements based on Laser-Induced Fluorescence (LIF), as well as with theoretical flow-field velocities, to better than 5% in all cases studied. C1 SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. RP Danehy, PM (reprint author), STANFORD UNIV,HIGH TEMP GASDYNAM LAB,STANFORD,CA 94305, USA. NR 15 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD APR PY 1996 VL 62 IS 4 BP 407 EP 413 DI 10.1007/BF01081203 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA UD732 UT WOS:A1996UD73200012 ER PT J AU Zolper, JC Wilson, RG Pearton, SJ Stall, RA AF Zolper, JC Wilson, RG Pearton, SJ Stall, RA TI Ca and O ion implantation doping of GaN SO APPLIED PHYSICS LETTERS LA English DT Article AB p- and n-type doping of GaN have been realized by ion implantation of Ca and O, respectively. Rapid thermal annealing at 1100 degrees C or higher is required to achieve p-type conduction in Ca or Ca+P implanted samples with an estimated ionization level of 169 meV and a corresponding activation efficiency of similar to 100%. This is the first experimental report of an acceptor species in GaN, other than Mg, with an ionization energy level less than 180 meV. O-implanted GaN displays an ionization level of similar to 29 meV but with an activation efficiency of only 3.6% after a 1050 degrees C anneal that may result from insufficient vacancy generation for the Lighter O ion or from the existence of a second, deeper O energy level. Neither Ca or O displayed measurable redistribution, based on secondary ion mass spectrometry measurements, even after a 1125 degrees C anneal. (C) 1996 American Institute of Physics. C1 HUGHES RES LABS,MALIBU,CA 90265. UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611. EMCORE CORP,SOMERSET,NJ 08873. RP Zolper, JC (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 18 TC 136 Z9 137 U1 4 U2 22 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 1 PY 1996 VL 68 IS 14 BP 1945 EP 1947 DI 10.1063/1.115634 PG 3 WC Physics, Applied SC Physics GA UC483 UT WOS:A1996UC48300022 ER PT J AU Zhang, Z Hammel, PC Wigen, PE AF Zhang, Z Hammel, PC Wigen, PE TI Observation of ferromagnetic resonance in a microscopic sample using magnetic resonance force microscopy SO APPLIED PHYSICS LETTERS LA English DT Article AB We report the observation of a ferromagnetic resonance signal arising from a microscopic (similar to 20 mu m X 40 mu m) particle of thin (3 mu m) yttrium iron garnet film using magnetic resonance force microscopy (MRFM). The large signal intensity in the resonance spectra suggests that MRFM could become a powerful microscopic ferromagnetic resonance technique with a micron or sub-micron resolution. We also observe a very strong nonresonance signal which occurs in the field regime where the sample magnetization readily reorients in response to the modulation of the magnetic field. This signal will be the main noise source in applications where a magnet, is mounted on the cantilever. (C) 1996 American Institute of Physics. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. RI Hammel, P Chris/O-4845-2014 OI Hammel, P Chris/0000-0002-4138-4798 NR 11 TC 122 Z9 123 U1 2 U2 18 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 1 PY 1996 VL 68 IS 14 BP 2005 EP 2007 DI 10.1063/1.115619 PG 3 WC Physics, Applied SC Physics GA UC483 UT WOS:A1996UC48300042 ER PT J AU SimmonsPotter, K Potter, BG McIntyre, DC Grandon, PD AF SimmonsPotter, K Potter, BG McIntyre, DC Grandon, PD TI Novel process for the production of large, stable photosensitivity in glass films SO APPLIED PHYSICS LETTERS LA English DT Article ID PLANAR WAVE-GUIDES; OPTICAL FIBERS; GRATINGS AB Germanosilicate glasses exhibit a significant photosensitive response which has been linked to the presence of oxygen-deficient germanium point defects in the glass structure. Based on this correlation, a process which produces highly photosensitive thin films without the use of hydrogen exposures, has been developed. This process, applicable to a wide range of desired xGeO(2): (1-x)SiO2 him composition, uses reactive atmosphere sputtering and allows extensive control of the degree of oxidation of the films during synthesis to produce dramatic demonstrations of photosensitivity. In preliminary tests, our films demonstrated ultraviolet-induced refractive index perturbations (Delta n) of up to -4X10(-3) in the visible and -0.4X10(-3) at 1.5 mu m. Since no hydrogen exposure was necessary, this process yielded stable films which retained their predisposition for large photosensitivity for over one year of storage. RP SimmonsPotter, K (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 19 TC 14 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 1 PY 1996 VL 68 IS 14 BP 2011 EP 2013 DI 10.1063/1.115621 PG 3 WC Physics, Applied SC Physics GA UC483 UT WOS:A1996UC48300044 ER PT J AU Baldwin, DP Zamzow, DS DSilva, AP AF Baldwin, DP Zamzow, DS DSilva, AP TI High-resolution spectroscopy using an acousto-optic tunable filter and a fiber-optic Fabry-Perot interferometer SO APPLIED SPECTROSCOPY LA English DT Article DE high-resolution spectroscopy; Fabry-Perot interferometry; acousto-optic tunable filter; inductively coupled plasma atomic emission spectroscopy; physical linewidths; isotope emission; actinides ID INDUCTIVELY COUPLED PLASMA; ATOMIC EMISSION-SPECTROMETRY; PROMINENT LINES; ELEMENTS; WIDTHS AB A compact, solid-state, high-resolution spectrometer consisting of an acousto-optic tunable filter (AOTF) and a fiber-optic Fabry-Perot (FFP) interferometer has been developed. The system has been designed for high-resolution inductively coupled plasma atomic emission spectroscopy (ICP-AES) applications. A description of the AOTF-FFP and its performance is presented. The resolution of the AOTF-FFP was determined by measuring the physical widths of ICP emission lines using a 1.5-m-focal-length grating spectrometer and deconvoluting the physical line shapes from the acquired AOTF-FFP spectra. Over the optimum range of the FFP mirror coatings, the resolution iii sufficient for the determination of isotopic and hyperfine emission features in ICP-AES experiments, and approaches that of the 1.5-m spectrometer. The application of the AOTF-FFP to the determination of uranium isotopes (U-235 and U-238) introduced into the ICP is presented. RP Baldwin, DP (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 25 TC 13 Z9 15 U1 0 U2 6 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1996 VL 50 IS 4 BP 498 EP 503 DI 10.1366/0003702963906032 PG 6 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA UE419 UT WOS:A1996UE41900011 ER PT J AU Dai, S Lee, YH Young, JP AF Dai, S Lee, YH Young, JP TI Observation of the surface-enhanced Raman scattering spectrum of uranyl ion SO APPLIED SPECTROSCOPY LA English DT Article DE uranyl ion; surface-enhanced Raman scattering; inorganic SERS; sol-gel C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. RI Dai, Sheng/K-8411-2015 OI Dai, Sheng/0000-0002-8046-3931 NR 6 TC 25 Z9 25 U1 1 U2 6 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1996 VL 50 IS 4 BP 536 EP 537 DI 10.1366/0003702963906122 PG 2 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA UE419 UT WOS:A1996UE41900018 ER PT J AU Bertie, JE VoDinh, T AF Bertie, JE VoDinh, T TI Spectroscopy commissions of the international union of pure and applied chemistry SO APPLIED SPECTROSCOPY LA English DT Editorial Material C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Bertie, JE (reprint author), UNIV ALBERTA,DEPT CHEM,EDMONTON,AB T6G 2G2,CANADA. NR 10 TC 5 Z9 6 U1 0 U2 1 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD APR PY 1996 VL 50 IS 4 BP A12 EP A20 PG 9 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA UE419 UT WOS:A1996UE41900002 ER PT J AU Cha, YS Yang, ZJ Evans, DJ Hull, JR AF Cha, YS Yang, ZJ Evans, DJ Hull, JR TI Induced current in a Bi2Sr2CaCu2Ox superconductor tube SO APPLIED SUPERCONDUCTIVITY LA English DT Article ID FAULT CURRENT LIMITER; PERFORMANCE; CERAMICS; FILMS AB Experiments were conducted to measure the induced current in a high-temperature Bi2Sr2CaCu2Ox superconductor tube that was excited by an external coil driven by an AC sinusoidal voltage source. Experimental data were obtained for tests without and with an iron core inside the superconductor tube. All of the tests were conducted at 77 K and an excitation frequency of 60 Hz. The results showed that immediately after field penetration, the induced current (RMS value) decreased from the critical current, then began to recover, and eventually approached the critical current again at a high excitation current. Before field penetration, the induced current was mainly shielding current, which is 180 degrees out of phase with the excitation current. After field penetration, the induced current consisted of two parts, a shielding current that led the excitation current by 180 degrees and an inductive current (Faraday's law) that led the excitation current by 90 degrees. The presence of the iron core amplified the drop in induced current immediately after field penetration and delayed the growth of the inductive current after field penetration. Published by Elsevier Science Ltd. RP Cha, YS (reprint author), ARGONNE NATL LAB,DIV ENERGY TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 16 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD APR PY 1996 VL 4 IS 4 BP 173 EP 184 DI 10.1016/S0964-1807(96)00026-9 PG 12 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA WJ375 UT WOS:A1996WJ37500002 ER PT J AU Leboeuf, JN Chen, KR Donato, JM Geohegan, DB Liu, CL Puretzky, AA Wood, RF AF Leboeuf, JN Chen, KR Donato, JM Geohegan, DB Liu, CL Puretzky, AA Wood, RF TI Modeling of dynamical processes in laser ablation SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID FLUID SIMULATION; PLASMAS AB Various physics and computational. approaches have been developed to globally characterize phenomena important for film growth by pulsed-laser deposition of materials. These include thermal models of laser-solid target interactions that initiate the vapor plume, plume ionization and heating through laser absorption beyond local thermodynamic equilibrium mechanisms, hydrodynamic and collisional descriptions of plume transport, and molecular dynamics models of the interaction of plume particles with the deposition substrate. RP Leboeuf, JN (reprint author), OAK RIDGE NATL LAB,POB 2009,OAK RIDGE,TN 37831, USA. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 17 TC 59 Z9 60 U1 0 U2 8 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 APR PY 1996 VL 96-8 BP 14 EP 23 DI 10.1016/0169-4332(95)00372-X PG 10 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600003 ER PT J AU Chen, KR Leboeuf, JN Wood, RF Geohegan, DB Donato, JM Liu, CL Puretzky, AA AF Chen, KR Leboeuf, JN Wood, RF Geohegan, DB Donato, JM Liu, CL Puretzky, AA TI Laser-solid interaction and dynamics of laser-ablated materials SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon AB An annealing model is extended to treat the vaporization process, and a hydrodynamic model describes the ablated material. We find that dynamic source and ionization effects accelerate the expansion front of the ablated plume with thermal vaporization temperature. The vaporization process and plume propagation in high background gas pressure are studied. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 12 TC 31 Z9 31 U1 1 U2 11 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 APR PY 1996 VL 96-8 BP 45 EP 49 DI 10.1016/0169-4332(95)00463-7 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600007 ER PT J AU Mao, XL Chan, WT Caetano, M Shannon, MA Russo, RE AF Mao, XL Chan, WT Caetano, M Shannon, MA Russo, RE TI Preferential vaporization and plasma shielding during nano-second laser ablation SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID INDUCTIVELY COUPLED PLASMA; ATOMIC-EMISSION-SPECTROMETRY; MASS-SPECTROMETRY; RADIATION; ALUMINUM; SAMPLES AB Preferential removal of components from mixed material targets and plasma shielding are studied by using inductively coupled plasma-atomic emission spectrometry (LCP-AES) during UV nano-second laser ablation. The ICP emission intensity for Cu and Zn during ablation of brass samples varies versus laser power density. A model using thermal evaporation and inverse Bremsstrahlung processes is presented. The model shows that plasma shielding occurs at approximately 0.3 GW/cm(2), in agreement with experimental data for change in the mass ablation rate. The good agreement of model and experimental data suggest that thermal effects are important during nano-second laser ablation for power density less than 0.3 GW/cm(2). C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV HONG KONG,DEPT CHEM,HONG KONG,HONG KONG. CENT UNIV VENEZUELA,ESCUELA QUIM,CARACAS 1020A,VENEZUELA. UNIV ILLINOIS,DEPT MECH ENGN,URBANA,IL 61801. NR 21 TC 59 Z9 63 U1 2 U2 13 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 APR PY 1996 VL 96-8 BP 126 EP 130 DI 10.1016/0169-4332(95)00420-3 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600021 ER PT J AU Geohegan, DB Puretzky, AA AF Geohegan, DB Puretzky, AA TI Laser ablation plume thermalization dynamics in background gases: Combined imaging, optical absorption and emission spectroscopy, and ion probe measurements SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID TRANSPORT AB Combined diagnostic measurements are employed to characterize the penetration of energetic ablation plumes through background gases during a key transitional regime in which the ion flux is observed (with fast ion probes) to split into distinct fast and slowed components. This apparently general phenomenon occurs over a limited range of distances at ambient pressures typically used for PLD (as reported for YBCO ablation into O-2) [1-5] and may be important to film growth by PLD because a 'fast' component of ions can arrive at the probe (or substrate) with little or no delay compared to propagation in vacuum (i.e., high 10-100 eV kinetic energies). At longer distances, this 'fast' component is completely attenuated, and only slowed distributions of ions are observed. interestingly, this 'fast' component is easily overlooked in imaging studies because the bright plume luminescence occurs in the slowed distribution. Time- and spatially-resolved optical absorption and emission spectroscopy are applied to experimentally determine the composition of the 'fast' and 'slow' propagating plume components for a single-component target ablation (yttrium) into an inert gas (argon) for correlation with quantitative imaging and ion probe measurements. The yttrium/argon system was chosen because optical absorption spectroscopy of both Y and Y+ was simultaneously possible [9] and the inert nature of argon. Experimental results for several other systems, including Si/Ar, Si/He, YBCO/O-2 are presented to illustrate variations in scattering mechanisms. Species-resolved imaging of YO* and Ba* is presented for the YBCO/O-2 system to illustrate the similarities and differences in the spatial regions of observed luminescence, These measurements confirm that, in addition to the bright significantly-slowed front which has been described by shock or drag propagation models [1], a fast-component of target material is transmitted to extended distances for some ambient pressures with near-initial velocities. C1 RUSSIAN ACAD SCI, INST SPECT, TROITSK 142092, RUSSIA. RP OAK RIDGE NATL LAB, DIV SOLID STATE, POB 2008, OAK RIDGE, TN 37831 USA. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 13 TC 55 Z9 55 U1 0 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 EI 1873-5584 J9 APPL SURF SCI JI Appl. Surf. Sci. PD APR PY 1996 VL 96-8 BP 131 EP 138 DI 10.1016/0169-4332(95)00421-1 PG 8 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600022 ER PT J AU Russo, RE Mao, XLL Caetano, M Shannon, MA AF Russo, RE Mao, XLL Caetano, M Shannon, MA TI Fundamental characteristics of laser-material interactions (ablation) in noble gases at atmospheric pressure using inductively coupled plasma-atomic emission spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID DEPOSITION AB Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) is used to study fundamental behavior underlying the explosive removal of solid material by high power pulsed laser irradiation. The influence of power density (irradiance) and carrier gas environment on the mass ablation rate behavior is discussed. Data are presented for nanosecond and picosecond laser ablation of metals. C1 CENT UNIV VENEZUELA,ESCUALE QUIM,CARACAS 1020A,VENEZUELA. UNIV ILLINOIS,DEPT MECH ENGN,URBANA,IL 61801. RP Russo, RE (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 10 TC 26 Z9 26 U1 0 U2 2 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 APR PY 1996 VL 96-8 BP 144 EP 148 DI 10.1016/0169-4332(95)00423-8 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600024 ER PT J AU Shannon, MA Russo, RE AF Shannon, MA Russo, RE TI Monitoring stress power during high-power pulsed laser-material interactions SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID SHOCK-WAVES; ABLATION; SURFACE AB High-power pulsed laser-material interactions are monitored with acoustic measurements of mechanical stress power. At laser intensities above 108 W/cm(2), an explosive, plasma forming interaction occurs between the laser beam and the solid target, ablating material away. Stresses in the target caused by the laser ablation can be very large, which for short pulsed laser ablation can make mechanical transport of energy significant. Experimental work is conducted to study the affect of laser intensity on stress power in the target and that carried by pressure waves in the surrounding gas medium. 30 ns excimer and 35 ps Nd:YAG lasers are used to ablate Al and Cu targets, and the resulting stresses are recorded by different types of transducers. The nanosecond results show that gas ionization breakdown can be detected through the stress power, and that the power measured follows a near quadratic dependence on the incident energy. Variations in the ratio of the shock power in air to the stress power in the target shows that plasma shielding of the laser beam can be monitored using the mechanical stress power. Differences in plasma shielding during pico-second ablation of copper in Ar versus He are shown using stress power monitoring. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA. RP Shannon, MA (reprint author), UNIV ILLINOIS,DEPT MECH ENGN,URBANA,IL 61801, USA. NR 14 TC 8 Z9 8 U1 0 U2 0 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 APR PY 1996 VL 96-8 BP 149 EP 153 DI 10.1016/0169-4332(95)00424-6 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600025 ER PT J AU Hess, WP German, KAH Bradley, RA McCarthy, MI AF Hess, WP German, KAH Bradley, RA McCarthy, MI TI Laser ablation of sodium nitrate: NO desorption following excitation of the pi-pi* band of the nitrate anion SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon AB We have studied the laser desorption of NO from single crystal sodium nitrate following pulsed laser excitation of the pi* <-- pi(2) absorption band localized on the nitrate anion. The excitation laser irradiance is maintained at low levels (<2 MW/cm(2)) to obtain product distributions free of secondary interactions following desorption from the crystal surface. At low fluence, the photodesorption yield is found to be linear with desorption laser power indicating that single-photon absorption leads to fragment ejection. The desorption yield is enhanced by a factor of at least 1000 for resonant excitation (213 nm) over nonresonant excitation (266 nn) on a per-photon basis. We determine the relative vibrational, rotational, and translational energy distributions of the neutral NO photoproducts. Significant population in vibrational levels up to v '' = 4 is observed. Rotational state populations and translational energy distributions are well characterized by thermal distributions at the substrate temperature. A local excitation mechanism for NO desorption is proposed, The structural and electronic properties of NaNO3 were calculated using ab initio periodic Hartree-Fock theory to investigate the photochemical mechanisms involved in laser desorption of this material, The results of the electronic structure calculations will be discussed in context with the experimental results. RP Hess, WP (reprint author), PACIFIC NW NATL LAB,POB 999,MS K2-14,RICHLAND,WA 99352, USA. NR 13 TC 10 Z9 10 U1 0 U2 1 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 APR PY 1996 VL 96-8 BP 321 EP 325 DI 10.1016/0169-4332(95)00439-4 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600053 ER PT J AU Norton, DP Chakoumakos, BC Lowndes, DH Budai, JD AF Norton, DP Chakoumakos, BC Lowndes, DH Budai, JD TI Formation of artificially-layered high-temperature superconductors using pulsed-laser deposition SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID CU-O SYSTEM; CA1-XSRXCUO2 THIN-FILMS; MOLECULAR-BEAM EPITAXY; HIGH-PRESSURE; UNIT-CELL; GROWTH; SR AB Superlattice structures, consisting of SrCuO2, (Ca,Sr)CuO2, and BaCuO2 layers in the tetragonal, 'infinite layer' crystal structure, have been grown by pulsed-laser deposition (PLD). Superlattice chemical modulation is observed for structures with component layers as thin as a single unit cell (similar to 3.4 Angstrom), indicating that unit-cell control of (Ca,Sr)CuO2 growth is possible using conventional pulsed-laser deposition over a wide oxygen pressure regime. X-ray diffraction intensity oscillations, due to the finite thickness of the film, indicate that these films are extremely flat with a thickness variation of only similar to 20 Angstrom over a length scale of several thousand angstroms. Using the constraint of epitaxy to grow metastable cuprates in the infinite layer structure, novel high-temperature superconducting structural families have been formed. In particular, epitaxially-stabilized (Ca,Sr)CuO2/BaCuO2 superlattices, grown by sequentially depositing on lattice-matched (100) SrTiO3 from BaCuO2 and (Ca,Sr)CuO2 ablation targets in a PLD system, show metallic conductivity and superconductivity at T-c(onset) similar to 70 K. These results show that pulsed-laser deposition and epitaxial stabilization have been used to effectively 'engineer' artificially-layered thin-film materials. RP Norton, DP (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. RI Chakoumakos, Bryan/A-5601-2016; Budai, John/R-9276-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543; Budai, John/0000-0002-7444-1306 NR 28 TC 4 Z9 4 U1 0 U2 2 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 APR PY 1996 VL 96-8 BP 672 EP 678 DI 10.1016/0169-4332(95)00542-0 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600116 ER PT J AU Reade, RP Russo, RE AF Reade, RP Russo, RE TI Ion-assisted pulsed-laser deposition for the fabrication of Y-Ba-Cu-O multilayer structures using oriented intermediate layers of YSZ and CeO2 SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID THIN-FILMS; BOMBARDMENT; ALLOYS AB One of the most significant recent applications of laser ablation is pulsed laser deposition (PLD), a powerful new technology for fabricating unique thin film compositions and structures. Ion-assisted PLD (IAPLD) enhances the capabilities of this technology by providing oriented thin-film structures on amorphous and randomly-ordered polycrystalline substrates. IAPLD is particularly well-suited for fabricating multilayer thin film structures suitable for high temperature superconducting multi-chip modules, We have fabricated such structures on 5.0 mu m SiO2 dielectric layers using IAPLD yttria-stabilized zirconia (YSZ) layers, obtaining critical current densities as high as 3 x 10(5) A/cm(2) at 77 K. We have also constructed YBCO/IAPLD-YSZ/SiO2/YSZ/YBCO/CeO2/YSZ and YBCO/IAPLD-YSZ/amorphous-YSZ/YBCO/CeO2/YSZ multilayers. In addition, we are working on IAPLD of oriented CeO2 layers to improve the YBCO critical current densities. C1 LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 10 TC 7 Z9 8 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 APR PY 1996 VL 96-8 BP 726 EP 730 DI 10.1016/0169-4332(95)00575-7 PG 5 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600127 ER PT J AU Puretzky, AA Geohegan, DB Jellison, GE McGibbon, MM AF Puretzky, AA Geohegan, DB Jellison, GE McGibbon, MM TI Comparative diagnostics of ArF- and KrF-laser generated carbon plumes used for amorphous diamond-like carbon film deposition SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Laser Ablation (COLA 95) CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP BM Ind, Cambridge Res Instruments, Cymer, DCA Instruments, Jobin Yvon, Lambda Phys, Neyco, Optec, Optovac, Princeton Instruments, Quantel, Sopra, Spiricon ID ABLATION; VACUUM AB A comparative study of ArF- and KrF-laser generated carbon plasmas has been performed under PLD conditions of amorphous diamond-like carbon (DLC) films. Gated-ICCD species-resolved imaging, luminescence spectroscopy and ion probe diagnostics have revealed distinct differences between the carbon plumes generated by ArF- and KrF-lasers. KrF-laser (6.7 J/cm(2)) irradiation produces a less energetic carbon plasma containing larger amounts of luminescent C-2 compared with ArF-laser ablation at the same energy fluence. Spectroscopic ellipsometry and EELS analysis of the DLC films deposited on Si[100] and NaCl substrates were utilized to characterize the high quality ArF- and KrF-laser deposited films (up to 84% of sp(3) bonded carbon for 7 J/cm(2) ArF-laser DLC film). The more energetic and highly-atomized ArF-laser carbon plasma appears to be responsible for the better diamond-like properties. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. UNIV GLASGOW,GLASGOW,LANARK,SCOTLAND. RP Puretzky, AA (reprint author), INST SPECTROSCOPY,TROITSK,RUSSIA. RI Puretzky, Alexander/B-5567-2016; Geohegan, David/D-3599-2013 OI Puretzky, Alexander/0000-0002-9996-4429; Geohegan, David/0000-0003-0273-3139 NR 10 TC 51 Z9 51 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 APR PY 1996 VL 96-8 BP 859 EP 865 DI 10.1016/0169-4332(95)00567-6 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600152 ER PT J AU Fogarassy, E Geohegan, D Stuke, M AF Fogarassy, E Geohegan, D Stuke, M TI Laser Ablation - Proceedings of Symposium F: Third International Symposium on Laser Ablation (COLA'95) of the 1995 E-MRS Spring Conference - Strasbourg, France, May 22-26, 1995 - Preface SO APPLIED SURFACE SCIENCE LA English DT Editorial Material C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. MAX PLANCK INST BIOPHYS CHEM,GOTTINGEN,GERMANY. RP Fogarassy, E (reprint author), CNRS,LAB PHASE,STRASBOURG,FRANCE. RI Geohegan, David/D-3599-2013 OI Geohegan, David/0000-0003-0273-3139 NR 0 TC 3 Z9 3 U1 0 U2 0 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 APR PY 1996 VL 96-8 BP R7 EP R7 PG 1 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA UU616 UT WOS:A1996UU61600001 ER PT J AU Borra, EF Levesque, S Beauchemin, M Morton, DC Stoughton, C Berk, DV York, DG Green, RF Crotts, APS AF Borra, EF Levesque, S Beauchemin, M Morton, DC Stoughton, C Berk, DV York, DG Green, RF Crotts, APS TI Spectroscopy of quasar candidates found with slitless spectroscopy .2. Six northern fields SO ASTRONOMICAL JOURNAL LA English DT Article ID STELLAR OBJECTS; OPTICAL CATALOG; TELESCOPE; SPECTRA; ATLAS; QSOS AB We are continuing the analysis of QSO candidates selected from objective spectra obtained with the CFHT. This paper describes six northern fields observed with the fiber-fed RC spectrograph on the Mayall Telescope, We obtained spectra at low resolution to confirm the QSOs and at higher resolution to find absorption-line systems. We found 61 new QSOs and confirmed 17 more which already had been reported in the region of the north galactic pole. Our spectra showed that seven of those previously known require significant changes to the published redshift, and one is a galaxy. There are three QSO pairs with comoving separations less than 10 (100/H-0) Mpc, if q(0) = 1/2. This number is only a factor 2 more than expected in a random sample, but two of these pairs have projected separations on the sky of 0.48 (100/H-0) and 0.41 (100/H-0) Mpc so that each could belong to a cluster with internal velocities around 1000 km s(-1). We found absorption lines in 36 QSOs including 3 which we have classified as broad-absorption-line QSOs. Line locking by A1 III or C IV absorption doublets occurs in two or three cases, The paper lists 30 new emission-line galaxies, 4 of which also have absorption lines, and 4 galaxies with only absorption lines. We found 5 white dwarfs, including one with broad absorption lines around 4270 and 4900 A in place of the usual Balmer series. An appendix of 62 identified stars includes 6 B stars and one O star. If we assume that the O star is a subdwarf with M(J) = 0.0. It must be 47 kpc above the galactic plane. C1 NATL RES COUNCIL CANADA,HERZBERG INST ASTROPHYS,VICTORIA,BC V8X 4M6,CANADA. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CHICAGO,CTR ASTRON & ASTROPHYS,CHICAGO,IL 60637. NATL OPT ASTRON OBSERV,TUCSON,AZ 85726. COLUMBIA UNIV,DEPT ASTRON,NEW YORK,NY 10027. RP Borra, EF (reprint author), UNIV LAVAL,DEPT PHYS,QUEBEC CITY,PQ G1K 7P4,CANADA. NR 25 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 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1996 VL 111 IS 4 BP 1456 EP 1497 DI 10.1086/117890 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UB962 UT WOS:A1996UB96200003 ER PT J AU Fryer, CL Benz, W Herant, M AF Fryer, CL Benz, W Herant, M TI The dynamics and outcomes of rapid infall onto neutron stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries, close; hydrodynamics; stars, neutron ID ADIABATIC ACCRETION FLOW; THORNE-ZYTKOW OBJECTS; BINARY PULSAR; CORES; HYDRODYNAMICS; EVOLUTION AB We present an extensive study of accretion onto neutron stars in which the velocity of the neutron star and structure of the surrounding medium is such that the Bondi-Hoyle accretion exceeds 10(-4) M. yr(-1). Two types of initial conditions are considered for a range of entropies and chemical compositions: an atmosphere in pressure equilibrium above the neutron star, and a freely falling inflow of matter from infinity (also parameterized by the infall rate). We then evolve the system with one- and two-dimensional hydrodynamic codes to determine the outcome. For most cases, hypercritical (also termed ''super Eddington'') accretion caused by rapid neutrino cooling allows the neutron star to accrete above the Bondi-Hoyle rate as previously pointed out by Chevalier. However, for a subset of simulations which corresponds to evolutionarily common events, convection driven by neutrino heating can lead to explosions by a mechanism similar to that found in core-collapse supernovae. Armed with the results from our calculations, we are in a position to predict the fate of a range of rapid-infall neutron star accretors present in certain low-mass X-ray binaries, common envelope systems, supernova fallbacks, and Thorne-Zytkow objects (TZOs). A majority of the common envelope systems that we considered led to explosions expelling the envelope, halting the neutron star's inward spiral, and allowing the formation of close binary systems. As a result, the smothered neutron stars produced in the collisions studied by Davies & Benz may also explode, probably preventing them from forming millisecond pulsars. For the most massive supernovae, in which the fallback of material toward the neutron star after a successful explosion is large, we find that a black hole is formed in a few seconds. Finally, we argue that the current set of TZO formation scenarios is inadequate and leads instead to hypercritical accretion and black hole formation. Moreover, it appears that many of the current TZ models have structures ill suited for modeling by mixing-length convection. This has prompted us to develop a simple test to determine the viability of this approximation for a variety of convective systems. C1 LOS ALAMOS NATL LAB,DIV THEORY,LOS ALAMOS,NM 87545. RP Fryer, CL (reprint author), UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721, USA. NR 52 TC 94 Z9 95 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1996 VL 460 IS 2 BP 801 EP 826 DI 10.1086/177011 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UB530 UT WOS:A1996UB53000021 ER PT J AU Smit, JM Cernohorsky, J VAndenHorn, LJ VanWeert, CG AF Smit, JM Cernohorsky, J VAndenHorn, LJ VanWeert, CG TI Effects of neutrino-electron scattering on neutrino transport in type II supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE elementary particles; scattering; stars, interiors; supernovae, general ID STELLAR CORE COLLAPSE AB We investigate the effects of neutrino-electron scattering on electron-neutrino transport during the collapse phase of a Type II supernova. Calculations of stationary state transport were performed on a 1.17 M. spherically symmetric infall model, with neutrino-electron scattering turned off and on, During the transport calculation, the stellar background is kept fixed in time. In this manner, we are able to isolate the effects of neutrino-electron scattering on neutrino transport alone. We find that the inclusion of neutrino-electron scattering approximately doubles the emitted neutrino flux during infall. Neutrino-electron scattering increases the rate at which energy and lepton number are transferred from the matter to the neutrinos. However, the transfer of entropy to the matter increases in a large part of the collapsing core. We also discuss the equilibration of the neutrinos. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Smit, JM (reprint author), UNIV AMSTERDAM,CHEAF,KRUISLAAN 403,1098 SJ AMSTERDAM,NETHERLANDS. NR 14 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1996 VL 460 IS 2 BP 895 EP 901 DI 10.1086/177017 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UB530 UT WOS:A1996UB53000027 ER PT J AU Fenimore, EE Klebesadel, RW Laros, JG AF Fenimore, EE Klebesadel, RW Laros, JG TI The 1979 March 5 gamma-ray transient: Was it a classic gamma-ray burst? SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts; radiation mechanisms, thermal; stars, individual (SGR 0526-66); stars, neutron ID HIGH-ENERGY TRANSIENT; REPEATER; EVENT; PERIODICITY; ABSORPTION; LOCATION; FEATURES AB The 1979 March 5 gamma-ray transient has long been thought to be fundamentally different from the classic gamma-ray bursts (GRBs). It had recurrences, pulsations, and a soft spectral component unlike classic GRBs. With the exception of the soft component reported from the KONUS experiment, the unusual characteristics of the March 5 transient were detectable primarily because it was extremely bright. Computer limitations, satellite transmission effects or pulse pileup, and dead-time effects have prevented, until now, the analysis of spectra from the International Cometary Explorer (ICE) and the Pioneer Venus Orbiter (PYO). The ICE-PVO spectrum of the main peak differs markedly from the published KONUS spectrum. Rather than being dominated by a soft component similar to that observed in the soft gamma repeaters (SGRs), the ICE-PVO spectrum appears to be consistent with a classic GRB spectrum, especially above 100 keV. Above 100 keV, the spectrum is consistent with thermal bremsstrahlung with a temperature of similar to 200 keV, somewhat soft but within the range of classic GRBs. We believe that, given the ICE-PVO spectral observations, the March 5 transient would have been classified as a classic GRB when it was discovered. Although a formal analysis has not been done, the pulsations and recurrences might still be unique features that distinguish the March 5 transient from GRBs. The ICE spectrum provides evidence for a low-energy cutoff at 100 keV. If high-velocity neutron stars are born as misaligned rotators with their velocities aligned with their spin axes and if their emissions are beamed, then when they are young their spatial distribution will be similar to the SGRs. If torques can align the field with the spin axis, then when they are old their spatial distribution will be isotropic like classic GRBs. Thus, the SGRs and GRBs could be consanguineous: high-velocity neutron stars initially produce SGR events (and, occasionally a GRB like the March 5 transient) and when they are older and in the galactic corona, they go through a GRB phase. The March 5 event demonstrates that high-velocity neutron stars at distances of tens of kiloparsecs are capable of producing events like classic GRBs. This reanalysis has revised the March 5 transient intensity upward such that the peak luminosity at an assumed distance of 55 kpc is 1.9 x 10(45) ergs s(-1). However, the March 5 event is consistent with the classic GRB log N-log P distribution and is not necessarily extraordinarily bright. RP Fenimore, EE (reprint author), LOS ALAMOS NATL LAB,D436,LOS ALAMOS,NM 87545, USA. NR 55 TC 34 Z9 34 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1996 VL 460 IS 2 BP 964 EP 975 DI 10.1086/177024 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UB530 UT WOS:A1996UB53000034 ER PT J AU Riley, WJ Gadgil, AJ Bonnefous, YC Nazaroff, WW AF Riley, WJ Gadgil, AJ Bonnefous, YC Nazaroff, WW TI The effect of steady winds on radon-222 entry from soil into houses SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE radon; wind; indoor air quality; contaminant transport; soil-gas transport ID TRANSPORT; BASEMENT; SYSTEMS; AIR AB Wind affects the radon-222 entry rate from soil into buildings and the resulting indoor concentrations. To investigate this phenomenon, we employ a previously tested three-dimensional numerical model of soil-gas Bow around houses, a commercial computational fluid dynamics code, an established model for determining ventilation rates in the presence of wind, and new wind tunnel results for the ground-surface pressure field caused by wind. These tools and data, applied under steady-state conditions to a prototypical residential building, allow us (1) to determine the complex soil-gas flow patterns that result from the presence of wind-generated ground-surface pressures, (2) to evaluate the effect of these flows on the radon concentration in the soil, and (3) to calculate the effect of wind on the radon entry rate and indoor concentration. For a broad range of soil permeabilities, two wind speeds, and two wind directions, we quantify the ''flushing'' effect of wind on the radon in the soil surrounding a house, and the consequent sharp decrease in radon entry rates. Experimental measurements of the time-dependent radon concentration in soil gas beneath houses confirm the existence of wind-induced flushing. Comparisons are made to modeling predictions obtained while ignoring the effect of the wind-generated ground-surface pressures. These investigations lead to the conclusion that wind-generated ground-surface pressures play a significant role in determining radon entry rates into residential buildings. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, INDOOR ENVIRONM PROGRAM, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, DEPT CIVIL ENGN, BERKELEY, CA 94720 USA. ECOLE NATL PONTS & CHAUSSEES, GRP INFORMAT & SYST ENERGET, F-93167 NOISY LE GRAND, FRANCE. RI Nazaroff, William/C-4106-2008; Riley, William/D-3345-2015; OI Nazaroff, William/0000-0001-5645-3357; Riley, William/0000-0002-4615-2304; Gadgil, Ashok/0000-0002-0357-9455 NR 26 TC 22 Z9 22 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD APR PY 1996 VL 30 IS 7 BP 1167 EP 1176 DI 10.1016/1352-2310(95)00248-0 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UA047 UT WOS:A1996UA04700016 ER PT J AU Kromidas, L Leifer, R AF Kromidas, L Leifer, R TI An innovative application of a commercially available double-sided adhesive for the collection of aerosols by impaction SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE aerosol; X-ray microanalysis; backscatter microscopy; automated electron microscopy; feature analysis ID BOUNCE AB We investigated a commercially available double-sided electrically conductive carbon adhesive for the collection of aerosols by impacters. This collection surface was found to be excellent for X-ray microanalysis since it does not contribute to the energy dispersive spectrum. X-ray microanalysis of this substrate showed it to contain only carbon and oxygen with carbon being the major component. The carbon substrate is ideal for backscatter electron microscopy because of maximal contrast differences between it and the collected noncarbonaceous particles. The characteristics of this substrate are advantageous for performing feature analysis and chemical characterization of aerosols by automated scanning electron microscopy. RP Kromidas, L (reprint author), US DOE,ENVIRONM MEASUREMENTS LAB,376 HUDSON ST,NEW YORK,NY 10014, USA. NR 7 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 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD APR PY 1996 VL 30 IS 7 BP 1177 EP 1180 DI 10.1016/1352-2310(95)00289-8 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UA047 UT WOS:A1996UA04700017 ER PT J AU Walmsley, JL Wesely, ML AF Walmsley, JL Wesely, ML TI Modification of coded parametrizations of surface resistances to gaseous dry deposition SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE dry deposition; surface resistance; acid deposition AB The parametrization scheme presented by Wesely (1989, Atmospheric Environment 23, 1293-1304) for surface resistance to gaseous dry deposition is examined. Some aspects of the scheme are clarified, errors are corrected and the corrected sample output is presented. In many cases, the new results are within about 10% of Wesely's original values for surface resistance. In other cases, they differ significantly, being as much as 23% lower or 50% higher than Wesely's values. These differences contribute to corresponding changes in deposition velocity that are as much as 30% higher or 33% lower, respectively, than those derived from Wesely's original computer code. Users of Wesely's parametrization scheme or his computer code are advised to check for possible incorrect results. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Walmsley, JL (reprint author), ATMOSPHER ENVIRONM SERV,DOWNSVIEW,ON M3H 5T4,CANADA. NR 4 TC 65 Z9 73 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD APR PY 1996 VL 30 IS 7 BP 1181 EP 1188 DI 10.1016/1352-2310(95)00403-3 PG 8 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UA047 UT WOS:A1996UA04700018 ER PT J AU Rhodes, OE Smith, LM Smith, MH AF Rhodes, OE Smith, LM Smith, MH TI Relationships between genetic variation and body size in wintering Mallards SO AUK LA English DT Article ID MULTIPLE-LOCUS HETEROZYGOSITY; AMERICAN BLACK DUCKS; PHYSIOLOGICAL ENERGETICS; NUTRIENT RESERVES; GROWTH; SURVIVAL; COMPONENTS; WEIGHT; AUTUMN; GEESE AB Mallards (Anas platyrhynchos; n = 282) wintering in the Southern High Plains (SHP) of Texas were collected from 15 October 1988 to 7 February 1989. Lipid and fat-free body masses were determined for all Mallards. Birds were surveyed electrophoretically for genetic variation at 30 biochemical loci. Our objective was to determine if structural size, fat mass, or fat-free mass of Mallards were related to multilocus genetic variation. Wing-chord length, our estimator of structural size in Mallards, was shortest in female Mallards with the highest levels of genetic variation. Fat mass and fat-free mass of Mallards (corrected for size) were not related to multilocus heterozygosity. Mixtures of morphologically and genetically differentiated breeding populations of Mallards on the SHP wintering area may explain the relationships between multilocus heterozygosity and size we detected in these birds. C1 SAVANNAH RIVER ECOL LAB,AIKEN,SC 29801. TEXAS TECH UNIV,DEPT RANGE & WILDLIFE MANAGEMENT,LUBBOCK,TX 79409. NR 49 TC 5 Z9 6 U1 0 U2 1 PU AMER ORNITHOLOGISTS UNION PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 SN 0004-8038 J9 AUK JI AUK PD APR PY 1996 VL 113 IS 2 BP 339 EP 345 PG 7 WC Ornithology SC Zoology GA UG666 UT WOS:A1996UG66600007 ER PT J AU Whitehead, JC AF Whitehead, JC TI Mini-launcher mass budget needed SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Letter RP Whitehead, JC (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD APR 1 PY 1996 VL 144 IS 14 BP 6 EP 6 PG 1 WC Engineering, Aerospace SC Engineering GA UD270 UT WOS:A1996UD27000002 ER PT J AU Volkow, ND Fowler, JS Wang, GJ Hitzemann, R Lieberman, J Angrist, B AF Volkow, ND Fowler, JS Wang, GJ Hitzemann, R Lieberman, J Angrist, B TI Dopaminergic modulation of frontal activity: Involvement in cocaine addiction SO BIOLOGICAL PSYCHIATRY LA English DT Meeting Abstract C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. SUNY STONY BROOK,STONY BROOK,NY 11794. NYU,NEW YORK,NY. HILLSIDE HOSP,NEW YORK,NY. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0006-3223 J9 BIOL PSYCHIAT JI Biol. Psychiatry PD APR 1 PY 1996 VL 39 IS 7 BP 33 EP 33 PG 2 WC Neurosciences; Psychiatry SC Neurosciences & Neurology; Psychiatry GA UE893 UT WOS:A1996UE89300029 ER PT J AU Quantock, AJ Klintworth, GK Schanzlin, DJ Capel, MS Lenz, ME Thonar, EJMA AF Quantock, AJ Klintworth, GK Schanzlin, DJ Capel, MS Lenz, ME Thonar, EJMA TI Proteoglycans contain a 4.6 angstrom repeat in macular dystrophy corneas: X-ray diffraction evidence SO BIOPHYSICAL JOURNAL LA English DT Article ID KERATAN SULFATE; STROMA; COLLAGEN; GLYCOSAMINOGLYCANS; HETEROGENEITY; ORGANIZATION; THICKNESS; LUMICAN; DECORIN; CDNA AB Synchrotron x-ray diffraction patterns from macular corneal dystrophy (MCD) corneas contain an unusual reflection that arises because of an undefined ultrastructure with a periodic repeat in the region of 4.6 , in this study, we compared the wide-angle x-ray diffraction patterns obtained from four normal human corneas and four MCD corneas. Moreover, portions of two of the MCD corneas were pretreated with a specific glycosidase to shed light on the origin of the 4.6 Angstrom reflection. None of the normal corneas produced an x-ray reflection in the region of 4.6 Angstrom, whereas all four of the MCD corneas did (MCD type I at 4.65 Angstrom and 4.63 Angstrom, MCD type II at 4.63 Angstrom and 4.67 Angstrom). This reflection was diminished after incubation of the MCD tissues with either chondroitinase ABC or N-glycanase. The findings indicate that glycosaminoglycans or proteoglycans contribute to the unusual MCD x-ray reflection and hence most likely contain a periodic 4.6 Angstrom ultrastructure. Furthermore, the results imply that periodic 4.6 Angstrom MCD ultrastructures reside in either intact, unsulfated lumican molecules and regions of the CS/DS-containing molecules or in a region of a hybrid macromolecular aggregate formed by the interaction of the two molecules. C1 DUKE UNIV,CTR EYE,DURHAM,NC. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973. RUSH PRESBYTERIAN ST LUKES MED CTR,DEPT BIOCHEM,CHICAGO,IL 60612. RUSH PRESBYTERIAN ST LUKES MED CTR,DEPT INTERNAL MED,CHICAGO,IL 60612. RP Quantock, AJ (reprint author), ST LOUIS UNIV,SCH MED,DEPT OPHTHALMOL,ANHEUSER BUSCH EYE INST,1755 S GRAND BLVD,ST LOUIS,MO 63104, USA. FU NEI NIH HHS [EY00146]; NIA NIH HHS [AG04736]; NIAMS NIH HHS [AR39239] NR 45 TC 9 Z9 9 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD APR PY 1996 VL 70 IS 4 BP 1966 EP 1972 PG 7 WC Biophysics SC Biophysics GA UB818 UT WOS:A1996UB81800041 PM 8785355 ER PT J AU Baker, EN Blundell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL AF Baker, EN Blundell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL TI Untitled SO BIOPOLYMERS LA English DT Letter C1 UNIV LONDON BIRKBECK COLL,DEPT CRYSTALLOG,IMPERIAL CANC RES FUND,STRUCT MOLEC BIOL UNIT,LONDON WC1E 7HX,ENGLAND. INDIAN INST SCI,MOLEC BIOPHYS UNIT,BANGALORE 560012,KARNATAKA,INDIA. YORK UNIV,DEPT CHEM,YORK YO1 5DD,N YORKSHIRE,ENGLAND. CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. WEIZMANN INST SCI,DEPT BIOL STRUCT,IL-76100 REHOVOT,ISRAEL. RP Baker, EN (reprint author), MASSEY UNIV,DEPT CHEM & BIOCHEM,PALMERSTON NORTH,NEW ZEALAND. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3525 J9 BIOPOLYMERS JI Biopolymers PD APR PY 1996 VL 38 IS 4 BP 437 EP 438 DI 10.1002/bip.360380402 PG 2 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA UA092 UT WOS:A1996UA09200001 ER PT J AU Sanderson, MA Reed, RL McLaughlin, SB Wullschleger, SD Conger, BV Parrish, DJ Wolf, DD Taliaferro, C Hopkins, AA Ocumpaugh, WR Hussey, MA Read, JC Tischler, CR AF Sanderson, MA Reed, RL McLaughlin, SB Wullschleger, SD Conger, BV Parrish, DJ Wolf, DD Taliaferro, C Hopkins, AA Ocumpaugh, WR Hussey, MA Read, JC Tischler, CR TI Switchgrass as a sustainable bioenergy crop SO BIORESOURCE TECHNOLOGY LA English DT Article; Proceedings Paper CT Alternative Energy Conference - Liquid Fuels, Lubricants and Additives from Biomass CY JUN 15-18, 1994 CL KANSAS CITY, MO SP Amer Soc Agr Engineers ID FORAGE GRASSES; UNITED-STATES; SEED DORMANCY; BIOMASS; ESTABLISHMENT; REGENERATION; BAHIAGRASS; YIELDS AB Switchgrass (Panicum virgatum L.) shows potential as a sustainable herbaceous energy crop from which a renewable source of transportation fuel and/or biomass-generated electricity could be derived. In 1992, a new research program focused on developing switchgrass as a biomass energy feedstock was initiated by the U.S. Department of Energy in five of the southern United States. The multifaceted multi-institution research addresses breeding for improved biomass yields, regional field rests, cultural practices, physiology and tissue culture. Recent progress is highlighted in this paper. Preliminary results from the breeding program indicate that recurrent restricted phenotypic selection could lead to development of new cultivars. A technique for regenerating switchgrass plants via tissue culture has been proven and new populations of regenerated plants have been established in the field. Performance trials at three regional cultivar testing centers in Virginia, Alabama and Texas have shown that 'Alamo' switchgrass has higher biomass yield and broader adaptability than other cultivars rested. Research on management practices designed to maximize biomass yield has shown that multiple harvests of switchgrass may reduce total seasonal yields in some instances and that responses to fertilizer inputs vary with the environment. Seed dormancy often retards rapid establishment of competitive stands of switchgrass. Our research has indicated that seed dormancy can be modified, resulting in increased seed germination and a greater number of switchgrass plants. Research on the physiology of switchgrass has shown that lowland and upland ecotypes differ in photosynthetic rate but not in respiration rate. Findings in each of these areas can contribute to development of switchgrass as a sustainable bioenergy crop. Future research will address molecular biology techniques for exploiting genetic variation, explore canopy architecture and carbon allocation patterns affecting biomass yield, elucidate key factors in successful establishment of switchgrass and provide technology transfer that facilitates scale-up of switchgrass production for commercial energy production. (C) 1996 Elsevier Science Ltd. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. UNIV TENNESSEE,DEPT PLANT SCI,KNOXVILLE,TN 37996. VIRGINIA TECH,DEPT CROP & SOIL ENVIRONM SCI,BLACKSBURG,VA. OKLAHOMA STATE UNIV,DEPT AGRON,STILLWATER,OK 74078. TEXAS A&M UNIV,AGR RES STN,BEEVILLE,TX. TEXAS A&M UNIV,DEPT SOIL & CROP SCI,COLLEGE STN,TX 77843. TEXAS A&M UNIV,CTR AGR RES & EXTENS,DALLAS,TX. USDA ARS,TEMPLE,TX 76502. RP Sanderson, MA (reprint author), TEXAS A&M UNIV,CTR AGR RES & EXTENS,STEPHENVILLE,TX 76401, USA. RI Wullschleger, Stan/B-8297-2012 OI Wullschleger, Stan/0000-0002-9869-0446 NR 47 TC 211 Z9 235 U1 5 U2 57 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0960-8524 J9 BIORESOURCE TECHNOL JI Bioresour. Technol. PD APR PY 1996 VL 56 IS 1 BP 83 EP 93 DI 10.1016/0960-8524(95)00176-X PG 11 WC Agricultural Engineering; Biotechnology & Applied Microbiology; Energy & Fuels SC Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels GA VG116 UT WOS:A1996VG11600013 ER PT J AU Wiselogel, AE Agblevor, FA Johnson, DK Deutch, S Fennell, JA Sanderson, MA AF Wiselogel, AE Agblevor, FA Johnson, DK Deutch, S Fennell, JA Sanderson, MA TI Compositional changes during storage of large round switchgrass bales SO BIORESOURCE TECHNOLOGY LA English DT Article; Proceedings Paper CT Alternative Energy Conference - Liquid Fuels, Lubricants and Additives from Biomass CY JUN 15-18, 1994 CL KANSAS CITY, MO SP Amer Soc Agr Engineers DE switchgrass; biomass; cellulose; hemicellulose; lignin; extractives; storage bales ID BIOMASS AB 'Alamo' switchgrass (Panicum virgatum L.) was harvested in two different years and stored as large round bales, unprotected outside, for 26 weeks. Fresh and scored switchgrass samples were analyzed for their structural and non-structural constituents. These summative analyses of the switchgrass showed differences in the composition of materials harvested at different rimes and indicated that the compositions changed during storage. On a dry weight, whole biomass basis, significant differences were observed in the extractives (+3%), ash (+1%), hemicelluloses (-1.4%), and cellulose (-4%) components of the switchgrass harvested in October 1991 relative to August 1992. The bales from the switchgrass harvested in October 1991 were exposed to high rainfall (65 cm) during storage and experienced much greater weathering than bales from the second harvest. The largest change in composition occurred in the ethanol-extractable component. The switchgrass showed a significant loss of extractives in both the weathered outer layer (11%) and the unweathered inner fraction (8%) of the bales prepared from the first harvest. Switchgrass harvested in August 1992 underwent much smaller compositional changes compared to the October 1991 harvest. The extractives in switchgrass and other grasses may contain substantial amounts of fermentable carbohydrates. If so, their loss during storage could have a significant impact on the conversion of switchgrass into ethanol. This is an example of the feedstock assessment research being conducted to determine the influence of harvest and storage conditions on the thermochemical and biochemical conversion of various biomass feedstocks into fuels and chemicals. The results of this research are expected to provide a guide to agricultural practices that optimize production of feedstocks for conversion into fuels. (C) 1996 Elsevier Science Ltd. C1 TEXAS A&M UNIV, CTR AGR RES & EXTENS, STEPHENVILLE, TX 76401 USA. RP NATL RENEWABLE ENERGY LAB, 1671 COLE BLVD, GOLDEN, CO 80401 USA. RI Johnson, David/G-4959-2011 OI Johnson, David/0000-0003-4815-8782 NR 20 TC 55 Z9 57 U1 1 U2 17 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0960-8524 EI 1873-2976 J9 BIORESOURCE TECHNOL JI Bioresour. Technol. PD APR PY 1996 VL 56 IS 1 BP 103 EP 109 DI 10.1016/0960-8524(95)00171-9 PG 7 WC Agricultural Engineering; Biotechnology & Applied Microbiology; Energy & Fuels SC Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels GA VG116 UT WOS:A1996VG11600015 ER PT J AU Arcot, SS Pesavento, JB Copeland, AC Masquelier, DA AF Arcot, SS Pesavento, JB Copeland, AC Masquelier, DA TI Device to facilitate colony hybridization SO BIOTECHNIQUES LA English DT Article ID FILTERS RP Arcot, SS (reprint author), LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94551, USA. NR 5 TC 0 Z9 0 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 APR PY 1996 VL 20 IS 4 BP 574 EP 576 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UD717 UT WOS:A1996UD71700007 PM 8800672 ER PT J AU Dombrowski, JE Raikhel, NV AF Dombrowski, JE Raikhel, NV TI Protein targeting to the plant vacuole - A historical perspective SO BRAZILIAN JOURNAL OF MEDICAL AND BIOLOGICAL RESEARCH LA English DT Review DE secretory pathways; protein targeting; receptors; endomembrane system; vacuolar sorting; membrane proteins ID TRANSGENIC TOBACCO PLANTS; PHASEOLUS-VULGARIS COTYLEDONS; CARBOXYL-TERMINAL PROPEPTIDE; TONOPLAST INTRINSIC PROTEIN; SUSPENSION-CULTURED CELLS; DEVELOPING PEA COTYLEDONS; YEAST CARBOXYPEPTIDASE-Y; POTATO TUBEROUS ROOTS; BARLEY THIOL PROTEASE; WHEAT-GERM-AGGLUTININ AB Although many properties of the targeting of plant endomembrane proteins are similar to mammalian and yeast systems, several clear differences are found that will be stressed in this review. In the past few years, we have seen an advancement in our understanding of the signals for vacuolar protein targeting and some insights into the mechanisms of transport to the vacuole in the plant cell. This work will form the basis for elucidation of the fundamental principles that govern protein trafficking through the secretory system to the vacuole. C1 MICHIGAN STATE UNIV,DOE PLANT RES LAB,E LANSING,MI 48824. NR 221 TC 1 Z9 1 U1 1 U2 2 PU ASSOC BRAS DIVULG CIENTIFICA PI SAO PAULO PA FACULDADE MEDICINA, SALA 21, 14049 RIBEIRAO PRETO, SAO PAULO, BRAZIL SN 0100-879X J9 BRAZ J MED BIOL RES JI Brazilian J. Med. Biol. Res. PD APR PY 1996 VL 29 IS 4 BP 413 EP 430 PG 18 WC Biology; Medicine, Research & Experimental SC Life Sciences & Biomedicine - Other Topics; Research & Experimental Medicine GA UE870 UT WOS:A1996UE87000002 PM 8736104 ER PT J AU Zink, S Illes, J Vannier, MW AF Zink, S Illes, J Vannier, MW TI NLM extramural program: Frequently asked questions SO BULLETIN OF THE MEDICAL LIBRARY ASSOCIATION LA English DT Article ID GRANT AB New and aspiring investigators often ask the same questions of experts as proposals are formulated, written, and submitted to the National Library of Medicine (NLM) for peer review. The NLM's Division of Extramural Programs (EP) provides support to medical libraries, academic medical centers, individuals, and industry through numerous types of grants and contracts. A complex set of processes and procedures is in place and is familiar to established and funded researchers, but to few others. A collection of frequently asked questions (FAQ) and their answers on these issues has been prepared by the Biomedical Library Review Committee (BLRC), a standing advisory group to the NLM that meets three times a year to review and score proposals. The BLRC and two experts on National Institutes of Health (NIH) grants and contracts compiled their advice in an electronic FAQ that has been edited and abridged as an introduction to NLM EP for investigators from medical library science, informatics, and biotechnology. The BLRC expects that if new investigators are able to avoid common mistakes and misconceptions, their proposals will improve in quality and they will be able to spend their time more effectively in proposal preparation. C1 WASHINGTON UNIV, MED CTR, MALLINCKRODT INST RADIOL, ST LOUIS, MO 63110 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. STANFORD UNIV, DEPT RADIOL, STANFORD, CA 94305 USA. OI Vannier, Michael/0000-0001-9898-384X NR 15 TC 2 Z9 2 U1 1 U2 2 PU MEDICAL LIBRARY ASSOC PI CHICAGO PA 65 EAST WACKER PLACE, STE 1900, CHICAGO, IL 60601-7298 USA SN 0025-7338 J9 B MED LIBR ASSOC JI Bull. Med. Libr. Assoc. PD APR PY 1996 VL 84 IS 2 BP 165 EP 181 PG 17 WC Information Science & Library Science SC Information Science & Library Science GA VA021 UT WOS:A1996VA02100001 PM 8826620 ER PT J AU Jones, EM Taylor, SR AF Jones, EM Taylor, SR TI Are L(g) spectra from NTS explosions self-similar? SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID NEVADA TEST SITE; YIELD ESTIMATION; DISCRIMINATION AB Network-averaged L(g) spectra for 106 underground Nevada Test Site (NTS) nuclear explosions (recorded at the four broadband seismic stations operated by Lawrence Livermore National Laboratory) are shown to be approximately selfsimilar and to scale with cavity radius and scaled-cavity radius. Composite spectra produced by superimposing the spectra of individual tests of nearly identical yields conducted in a single geologic unit (e.g., Tunnel Beds tuff, Yucca Flat, below the water table) have amplitude variability of about a factor of 2. If a master spectrum is chosen that resembles the shape of a particular subgroup of nearly identical NTS explosions, the spectra of all other tests in the database can be superimposed on the master spectrum through the application of a shot-specific amplitude shift and a shot-specific frequency shift. The amplitude shift basically measures the difference between the low-frequency asymptotes of the individual spectrum and the master spectrum, and the frequency shift measures the difference in corner frequencies. We show that, for explosions producing cavities with a narrow range of measured scaled-cavity radii, the amplitude shifts scale with cavity volume. Further, if cavity volume scaling is applied to the amplitude shifts, the residuals are shown to depend on scaled-cavity radius or gas-filled porosity. The residuals (a measure of seismic coupling) appear to show slightly reduced scatter when plotted versus scaled-cavity radius as opposed to gas-filled porosity. The frequency shifts scale approximately as cavity radius to the 3/4 power. Although the NTS L(g) spectra are approximately self-similar, differences in high-frequency decay and other shape parameters exist. For example, the rate of high-frequency decay is observed to progressively decrease as explosions approach the static water level from above. These differences do not have a significant effect on the connections established between the amplitude and frequency shifts with cavity radius and other source parameters but do suggest source differences of potential interest in discrimination studies. RP Jones, EM (reprint author), LOS ALAMOS NATL LAB,DIV EARTH & ENVIRONM SCI,LOS ALAMOS,NM 87545, USA. NR 21 TC 4 Z9 4 U1 0 U2 2 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 APR PY 1996 VL 86 IS 2 BP 445 EP 456 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA UJ351 UT WOS:A1996UJ35100016 ER PT J AU McNamara, DE Owens, TJ Walter, WR AF McNamara, DE Owens, TJ Walter, WR TI Propagation characteristics of Lg across the Tibetan Plateau SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID FREQUENCY-DEPENDENT ATTENUATION; LATERAL VARIATIONS; WAVE-PROPAGATION; SHEAR-WAVES; SIMULTANEOUS INVERSION; CRUSTAL STRUCTURE; CENTRAL FRANCE; NORTH-AMERICA; BENEATH TIBET; MANTLE AB We present the results of a study on the propagation of Lg within the Tibetan Plateau. We analyze over 1200 seismograms for Lg propagation from 185 local and regional earthquakes recorded at distances from 150 to 2000 km, 52 of which are located within the Tibetan Plateau. Although the propagation of Lg has been observed across most of Asia, Lg has not been observed for paths crossing the Tibetan Plateau. We analyze paths that cross the plateau boundaries and paths contained entirely within the Tibetan Plateau. Lg is generated within the Tibetan Plateau and can propagate to epicentral distances of at least 600 km. For events located outside of the Tibetan Plateau, Lg is either absent or severely diminished for paths that cross both the Himalayan and Kunlun ranges, confirming that the margins of the plateau weaken Lg transmission. Based on the observations from our qualitative analysis, we invert Lg amplitudes for event/station paths that are confined to the Tibetan Plateau to estimate the quality factor, Q. The inversion yields a frequency-dependent Q function: Q(f) = (366 +/- 37)f((0.45+/-0.06)) (0.5 less than or equal to f less than or equal to 16 Hz). Similar observations in other areas indicate that frequency-dependent apparent Q within the Tibetan Plateau is well below that expected for a typical continental interior. Instead, it has a frequency dependence that is characteristic of a tectonically active region. C1 UNIV S CAROLINA,DEPT GEOL SCI,COLUMBIA,SC 29208. LAWRENCE LIVERMORE NATL LAB L202,DIV EARTH SCI,LIVERMORE,CA 94550. RI Walter, William/C-2351-2013 OI Walter, William/0000-0002-0331-0616 NR 58 TC 72 Z9 74 U1 1 U2 4 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 APR PY 1996 VL 86 IS 2 BP 457 EP 469 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA UJ351 UT WOS:A1996UJ35100017 ER PT J AU Kandl, KL Thompson, AJ AF Kandl, KL Thompson, AJ TI Responses of eastern mosquitofish (Gambusia holbrooki) to acute salinity stress: Do family effects obscure inbreeding and genotype effects? SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID INORGANIC MERCURY EXPOSURE; ALLOZYME GENOTYPE; RECOVERY EFFORTS; AFFINIS BAIRD; POPULATION; TIME; GENETICS; DEATH; CONSERVATION; DEPRESSION AB Eastern mosquitofish (Gambusia holbrooki) having inbreeding coefficients of 0, 0.125, and 0.25 were exposed to a salinity stress of 14.34 parts per thousand (ppt) for 96 h, and their survival times were determined. Statistical models were fitted to the failure-time data to assess differences between the survival functions based on inbreeding coefficient, family, and genotype of the fish. Predicted median survival times were determined for inbreeding classes, families within inbreeding classes, classes based on number of heterozygous loci, and genotypes at single loci. Family significantly affected survival of individuals in all analyses, regardless of the inbreeding coefficient of the individual. The inbreeding coefficient of an individual did not statistically affect survival. The number of heterozygous loci per individual significantly affected survival time but only when family as well as number of heterozygous loci per individual were included as independent variables in the analysis. Genotypes of two loci, m-isocitrate dehydrogenase A and glucose phosphate isomerase B, also significantly affected survival. Our study demonstrates that family can account for a greater proportion of the variance in survival under environmental stress than either inbreeding coefficient or number of heterozygous loci. Family effects, in addition to inbreeding, should be considered in conservation management plans. C1 UNIV GEORGIA, DEPT ZOOL, ATHENS, GA 30602 USA. UNIV GEORGIA, INST ECOL, ATHENS, GA 30602 USA. RP Kandl, KL (reprint author), SAVANNAH RIVER ECOL LAB, DRAWER E, AIKEN, SC 29802 USA. NR 43 TC 7 Z9 7 U1 0 U2 3 PU CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS PI OTTAWA PA 65 AURIGA DR, SUITE 203, OTTAWA, ON K2E 7W6, CANADA SN 0706-652X EI 1205-7533 J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1996 VL 53 IS 4 BP 753 EP 760 DI 10.1139/cjfas-53-4-753 PG 8 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA VD063 UT WOS:A1996VD06300008 ER PT J AU Letcher, BH Rice, JA Crowder, LB Rose, KA AF Letcher, BH Rice, JA Crowder, LB Rose, KA TI Variability in survival of larval fish: Disentangling components with a generalized individual-based model SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID HERRING CLUPEA-HARENGUS; POPULATION-DYNAMICS; MENIDIA-BERYLLINA; ENGRAULIS-MORDAX; MARINE FISHES; JACK MACKEREL; OXYGEN-UPTAKE; STRIPED BASS; FOOD DENSITY; GROWTH AB Many factors, including intrinsic characteristics of the fish themselves and extrinsic factors of the biological environment, have the potential to regulate mortality rates during the early life of fishes. We used a detailed simulation model to rank the effects of variability in these factors on larval and early juvenile survival. Our major finding was that proportional changes in the intrinsic and extrinsic factors in the model had equal effects on cohort survival. Of the intrinsic factors, growth capacity (metabolism and assimilation efficiency), not foraging ability or starvation resistance, explained the most variance in survival. Of the extrinsic factors, predator size explained 83% of the variability in survival but proportional changes prey availability had only a minor effect. Variability in prey density required a 3-fold increase to equal the effects of predator size on survival. Despite the important effects of predation pressure on survival, it had only a minor impact on how fish died. Whether fish died from predation or starvation depended much more on the intrinsic variables related to metabolism and starvation resistance and on the density of the smallest prey type. C1 N CAROLINA STATE UNIV,DEPT ZOOL,RALEIGH,NC 27695. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. NR 85 TC 124 Z9 125 U1 0 U2 25 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1996 VL 53 IS 4 BP 787 EP 801 DI 10.1139/cjfas-53-4-787 PG 15 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA VD063 UT WOS:A1996VD06300012 ER PT J AU Hill, WR Stewart, AJ Napolitano, GE AF Hill, WR Stewart, AJ Napolitano, GE TI Mercury speciation and bioaccumulation in lotic primary producers and primary consumers SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID ROOM-TEMPERATURE PRECOLLECTION; ALGAL BIOMASS; ACCUMULATION; METHYLMERCURY; STREAM; FISH; CONTAMINATION; ETHYLATION; FORM; GOLD AB Mercury speciation and bioaccumulation were strongly affected by trophic position and distance from contamination source in this study of lower trophic levels in two eastern Tennessee streams. Methylmercury and inorganic mercury (Hg(II)) were analyzed in samples of periphyton, grazing fish (stonerollers, Campostoma anomalum), and omnivorous fish (striped shiners, Luxilus chysocephalus) taken from three sites in an industrially contaminated stream and one site in a reference stream. Inorganic mercury predominated in periphyton and fish samples from all sites, always exceeding 50% of total mercury. However, the proportion of methylmercury increased significantly with both trophic level and distance downstream. Bioconcentration factors for methylmercury increased 0.5-1.5 log units per trophic level at all sites, implying significant biomagnification of this species. Bioconcentration factors for Hg(II) declined with increasing trophic level at three of the four sites and were 1-2 log units lower than those for methylmercury, providing little evidence of Hg(II) biomagnification. Primary producers and primary consumers are critical intermediaries in the movement and biomagnification of mercury from water to upper trophic levels. RP Hill, WR (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. OI stewart, arthur/0000-0003-1968-5997 NR 29 TC 68 Z9 68 U1 1 U2 26 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1996 VL 53 IS 4 BP 812 EP 819 DI 10.1139/cjfas-53-4-812 PG 8 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA VD063 UT WOS:A1996VD06300014 ER PT J AU McLaughlin, SB Downing, DJ AF McLaughlin, SB Downing, DJ TI Interactive effects of ambient ozone and climate measured on growth of mature loblolly pine trees SO CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE LA English DT Article; Proceedings Paper CT 16th International Meeting for Specialists in Air Pollution Effects on Forest Ecosystems - Air Pollution and Multiple Stresses CY SEP 07-09, 1994 CL FREDERICTON, CANADA SP Nat Resources Canada, Canadian Forest Serv, Fredericton ID SOUTHEASTERN UNITED-STATES; AIR-POLLUTION; EXPOSURE; RESPONSES; DECLINE; STANDS; RAIN AB Seasonal growth patterns of mature loblolly pine (Pinus taeda L.) trees over the interval 1988-1993 have been analyzed to evaluate the effects of ambient ozone on growth of large forest trees. Patterns of stem expansion and contraction of 34 trees were examined using serial measurements with sensitive dendrometer band systems. Study sites, located in eastern Tennessee, varied significantly in soil moisture, soil fertility, and stand density. Levels of ozone, rainfall, and temperature varied widely over the 6-year study interval. Regression analysis identified statistically significant influences of ozone on stem growth patterns, with responses differing widely among trees and across years. Ozone interacted with both soil moisture stress and high temperatures, explaining 63% of the high frequency, climatic variance in stem expansion identified by stepwise regression of the 5-year data set. Observed responses to ozone were rapid, typically occurring within 1-3 days of exposure to ozone at greater than or equal to 40 ppb and were significantly amplified by low soil moisture and high air temperatures. Both shortterm responses, apparently tied to ozone-induced increases in whole-tree water stress, and longer term cumulative responses were identified. These data indicate that relatively low levels of ambient ozone can significantly reduce growth of mature forest trees and that interactions between ambient ozone and climate are likely to be important modifiers of future forest growth and function. Additional studies of mechanisms of short-term response and interspecies comparisons are clearly needed. C1 OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,OAK RIDGE,TN 37831. RP McLaughlin, SB (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. NR 49 TC 30 Z9 30 U1 0 U2 2 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 APR PY 1996 VL 26 IS 4 BP 670 EP 681 PG 12 WC Forestry SC Forestry GA UH468 UT WOS:A1996UH46800020 ER PT J AU White, DC Ringelberg, DB AF White, DC Ringelberg, DB TI Monitoring deep subsurface microbiota for assessment of safe long-term nuclear waste disposal SO CANADIAN JOURNAL OF MICROBIOLOGY LA English DT Review DE nuclear waste; deep subsurface; microbiota; microbial corrosion; safe long-term storage; signature lipid biomarkers ID POLY-BETA-HYDROXYBUTYRATE; FATTY-ACIDS; COMMUNITY STRUCTURE; NUTRITIONAL-STATUS; DETRITAL MICROBIOTA; SEDIMENTS; BIOMASS; ACCUMULATION; BACTERIA; TRANS AB Microbes with their resistance to heat and radioactivity, if present and metabolically active, could have major effects on the safety of nuclear waste disposal by posing potential problems in long-term containment. This paper reviews the applicability of the signature lipid biomarker (SLB) analysis in the quantitative assessment of the viable biomass, community composition, and nutritional/physiological status of the subsurface microbiota as it exists in situ in subsurface samples. The samples described in this review are not unlike those expected to be recovered from proposed deep subsurface disposal sites. Assessment of the microbial community ecology using SLB analysis can be utilized to predict potential problems engendered by microbial metabolic activities of these communities in breaching containment by microbially facilitated corrosion and in the potential for subsequent facilitated transport of nuclides into the environment. SLB analysis of the in situ microbial ecology can be utilized to monitor the feasibility of containment options in modeling tests at the specific disposal sites. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37983. UNIV TENNESSEE,DEPT MICROBIOL,KNOXVILLE,TN 37996. RP White, DC (reprint author), UNIV TENNESSEE,CTR ENVIRONM BIOTECHNOL,10515 RES DR,SUITE 300,KNOXVILLE,TN 37932, USA. NR 41 TC 8 Z9 9 U1 0 U2 4 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4166 J9 CAN J MICROBIOL JI Can. J. Microbiol. PD APR PY 1996 VL 42 IS 4 BP 375 EP 381 PG 7 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Immunology; Microbiology GA UE280 UT WOS:A1996UE28000009 ER PT J AU Ariese, F Small, GJ Jankowiak, R AF Ariese, F Small, GJ Jankowiak, R TI Conformational studies of depurinating DNA adducts from syn-dibenzo[a,l]pyrene diolepoxide SO CARCINOGENESIS LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; TUMOR-INITIATING ACTIVITY; MOUSE SKIN; DIOL-EPOXIDES; BENZOPYRENE; 7,12-DIMETHYLBENZANTHRACENE; MUTAGENICITY; DIBENZOPYRENE; TUMORIGENICITY; CARCINOGENESIS AB One of the major DNA adducts from the extremely potent aromatic carcinogen dibenzo[a,l]pyrene (DB[a,l]P) is the depurinating adduct syn-DB[a,l]P diolepoxide-14-N7Ade. Low-temperature fluorescence spectra of this adduct (and related derivatives bound to N3-adenine and N7-guanine) showed two distinct (0,0) origin bands with different excited-state vibrational frequencies, as measured by means of fluorescence line narrowing spectroscopy, The relative intensity of the two origin bands was solvent dependent, The hypothesis that this phenomenon could be due to a conformational equilibrium was tested using molecular mechanics, dynamical simulations and semi-empirical quantum-mechanical calculations, The hydrolyzed metabolite DB[a,l]P tetraol was also studied for comparison, It was found that the syn-DB[a,l]P diolepoxide-14-N7Ade adduct is formed via trans addition to the epoxide, Exploration of the conformational space indeed produced two potential energy minima; both corresponding to structures in which the aromatic ring system is severely distorted, In conformation I the proximity of the distal ring forces the adenine base into a pseudo-axial position and the cyclohexenyl ring adopts a half-boat structure, In conformation II the distal ring is bent in the opposite direction, allowing the cyclohexenyl ring to adopt a half-chair structure with the base in a pseudo-equatorial position, partially stacked over the distal ring, The difference in (0,0) transition energy calculated for the two conformers agrees very well with the spectroscopic data, and the relative orientations of the hydrogens bound to the cyclohexenyl ring in the major (half-boat) conformation I are in full agreement with the experimentally observed proton NMR coupling constants. C1 IOWA STATE UNIV,AMES LAB,US DOE,AMES,IA 50011. IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. FU NCI NIH HHS [P0I CA49210-05] NR 43 TC 19 Z9 19 U1 0 U2 0 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 APR PY 1996 VL 17 IS 4 BP 829 EP 837 DI 10.1093/carcin/17.4.829 PG 9 WC Oncology SC Oncology GA UG814 UT WOS:A1996UG81400031 PM 8625498 ER PT J AU Hanagandi, V Ploehn, H Nikolaou, M AF Hanagandi, V Ploehn, H Nikolaou, M TI Solution of the self-consistent field model for polymer adsorption by genetic algorithms SO CHEMICAL ENGINEERING SCIENCE LA English DT Article AB A Genetic Algorithm (GA) is used to solve the equations of the self-consistent field model for polymer adsorption on a surface. The solution is cast as an optimization problem and a GA is used as a function optimizer to solve this problem. Comparison is made with a traditional gradient-based approach. It was found that convergence properties will improve if the GA is cascaded with a gradient search method. This cascaded search method guarantees convergence from any random initial population of guesses and does not need insight into the physics of the problem. C1 UNIV S CAROLINA,DEPT CHEM ENGN,SWEARINGEN ENGN CTR,COLUMBIA,SC 29208. TEXAS A&M UNIV,DEPT CHEM ENGN,COLLEGE STN,TX 77843. RP Hanagandi, V (reprint author), LOS ALAMOS NATL LAB,COMPUTAT SCI METHODS DIV,MS C312,LOS ALAMOS,NM 87545, USA. NR 7 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD APR PY 1996 VL 51 IS 7 BP 1071 EP 1078 DI 10.1016/0009-2509(95)00346-0 PG 8 WC Engineering, Chemical SC Engineering GA UA399 UT WOS:A1996UA39900006 ER PT J AU Marcus, E Keller, DA Shibata, M Ornstein, RL Rein, R AF Marcus, E Keller, DA Shibata, M Ornstein, RL Rein, R TI Comparing theoretical and experimental backbone-dependent sidechain conformational preferences for linear, branched, aromatic and polar residues SO CHEMICAL PHYSICS LA English DT Article ID SIDE-CHAIN CONFORMATIONS; OCCURRING AMINO-ACIDS; PANCREATIC TRYPSIN-INHIBITOR; HYDROGEN-BOND INTERACTIONS; ENERGY PARAMETERS; NONBONDED INTERACTIONS; PROTEIN CONFORMATION; MOLECULAR-DYNAMICS; GLOBULAR-PROTEINS; ALANINE DIPEPTIDE AB An Ecepp-3 conformational study based on a phi-psi, grid search with sidechain minimization was carried out on the N-acetyl N'-methyl amides of four representative amino acids: Met, Phe, Ile, and Ser, and the distribution of X(1) backbone-dependent rotamer preferences was compared with the similar distribution obtained from the backbone-dependent rotamer library for proteins developed by Dunbrack and Karplus (J, Mol. Biol, 230 (1993) 543), The experimental distribution is best reproduced theoretically in the case of the linear sidechain of Met, reasonably well for the bulky sidechains of the aromatic Phe and asymmetrically P-branched Ile, and only partially for the short polar sidechain of Ser. In the case of the Ser dipeptide the difference is accounted for by the missing H bonds. C1 ROSWELL PK CANC INST, DEPT BIOPHYS, BUFFALO, NY 14263 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NR 40 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD APR 1 PY 1996 VL 204 IS 2-3 BP 157 EP 171 DI 10.1016/0301-0104(95)00361-4 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD543 UT WOS:A1996UD54300002 ER PT J AU Manchester, JI Paulsen, MD Rein, R Ornstein, RL AF Manchester, JI Paulsen, MD Rein, R Ornstein, RL TI 1,1,1-Trichloroethane-bound cytochrome P450cam dynamics. Does active site water make a difference? SO CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; REDUCTIVE DEHALOGENATION; SUBSTRATE MOBILITY; CRYSTAL-STRUCTURE; SIMULATION; SPIN AB Cytochrome P450cam is capable of reductively dehalogenating several chlorinated alkanes at slow, but measurable, rates. To gain insight into the dynamic properties of the enzyme having an influence over its reactivity, molecular dynamics (Mo) simulations are performed on the complex of wild-type P450cam and 1,1,1-trichloroethane (TCA), a long-lived pollutant. Previous simulations on this complex indicated that, unlike the enzyme complexed with camphor and camphor analogs, the behavior of TCA is sensitive to electrostatic interactions with the heme-Fe cofactor. Using recently developed partial charges for the heme, we conducted two 300 ps MD simulations on TCA-bound P450cam. Since water bound in the enzyme active site is thought to be an important mediator of catalysis, in one simulation three additional water molecules are docked into space left void when the native substrate, camphor, is replaced with TCA. For the majority of configurations sampled, TCA in close proximity to the heme-Fe, suggesting that, if a high degree of spin conversion were achieved, degradation of TCA might proceed at a measurable rate. In the simulation without active site water, TCA samples an alternate binding pocket that opens due to rearrangement of active site residues, leaving room for water to presumably coordinate Fe. This result is consistent with the experimental observation that TCA causes only a minor degree of heme spin conversion. The presence of active site water inhibits these significant dynamic fluctuations in the active site, indicating that including extra water molecules in this binding pocket does not provide information crucial to understanding dynamic properties of the enzymes that influence the behavior of TCA. C1 PACIFIC NW LAB, ENVIRONM MOLEC SCI LAB, RICHLAND, WA 99352 USA. ROSWELL PK CANC INST, DEPT BIOPHYS, BUFFALO, NY 14263 USA. NR 28 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD APR 1 PY 1996 VL 204 IS 2-3 BP 223 EP 231 DI 10.1016/0301-0104(95)00412-2 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD543 UT WOS:A1996UD54300008 ER PT J AU Parkin, S Marsch, GA Hope, H Whitney, E Winter, NW Colvin, ME Felton, JS Turteltaub, KW AF Parkin, S Marsch, GA Hope, H Whitney, E Winter, NW Colvin, ME Felton, JS Turteltaub, KW TI Comparison of crystal structure and theory for 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Article ID HETEROCYCLIC AMINES; FOOD MUTAGEN; PYRIDINE PHIP; COOKED-BEEF; CARCINOGEN; IDENTIFICATION; DNA; 2'-DEOXYGUANOSINE; GENOTOXICITY; METABOLISM AB The crystal structure of the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) has been determined by single-crystal X-ray crystallography. Crystals grown by evaporation of an aqueous solution form in the monoclinic space group P2(1)/n with two molecules of PhIP per asymmetric unit, along with six water molecules. The phenyl groups of these two PhIP molecules have torsion angles of different magnitude with respect to the plane of the imidazopyridine moiety. To maintain centrosymmetry, the crystal also contains an oppositely torsioned symmetry equivalent of each. The amino groups of both PhIP molecules take part in an extensive hydrogen bond network with the water of crystallization, forming long channels through the crystals parallel to the crystallographic b axis. The diffraction results are compared to theoretical calculations of the optimized geometry for a single PhIP molecule in vacuo as well as with water hydrogen-bonded to the exocyclic amine. In general, the agreement between the X-ray crystal structure of PhIP and its theory-derived counterpart in vacuo is within the combined experimental-theoretical uncertainty. The C-N bond to the exocyclic amine and the neighboring C=N imidazole bond are exceptions. This is attributed to the combined neglect of the crystal environment, waters of hydration, and the lack of coplanarity between the imidazole ring and the amine group in the calculations. To address the effect of waters of hydration, additional calculations were performed to optimize the geometry of a PhIP molecule with two water molecules hydrogen-bonded to the exocyclic amine. The resulting C-N exocyclic amine and C=N imidazole bond lengths were closer to those obtained by X-ray diffraction. The accord between theory and experiment demonstrates the utility of applying theory to (1) accurately predict structures of PhIP metabolites and intermediates that are too labile for study by conventional structural techniques such as X-ray crystallography and (2) assist in studying the mechanisms by which PhIP and its metabolites interact with proteins and DNA. C1 LAWRENCE LIVERMORE NATL LAB,MOLEC & STRUCT BIOL DIV,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94550. UNIV CALIF DAVIS,DEPT CHEM,DAVIS,CA 95616. WILLIAMS COLL,WILLIAMS,MA 01267. SANDIA NATL LABS,LIVERMORE,CA 94551. RI Parkin, Sean/E-7044-2011 FU NCI NIH HHS [CA55861] NR 35 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0893-228X J9 CHEM RES TOXICOL JI Chem. Res. Toxicol. PD APR-MAY PY 1996 VL 9 IS 3 BP 574 EP 579 DI 10.1021/tx950168b PG 6 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA UF846 UT WOS:A1996UF84600003 PM 8728500 ER PT J AU Blatter, F Sun, H Frei, H AF Blatter, F Sun, H Frei, H TI Highly selective formation of tert-butyl hydroperoxide from the reaction of isobutane and O-2 in a zeolite under visible light SO CHEMISTRY-A EUROPEAN JOURNAL LA English DT Article DE hydroperoxides; isobutane; oxygen; photooxidations; zeolites ID CATION AB Isobutane and oxygen gas loaded into zeolite BaY react upon irradiation with green or blue light to yield tert-butyl hydroperoxide in a single-photon process. This was discovered when monitoring the reaction at room temperature in situ by FT-infrared spectroscopy. Selectivity was 98%, even upon conversion of more than half of the reactants loaded into the zeolite. Diffuse reflectance spectra revealed a visible absorption tail which originates from an isobutane . O-2 collision complex. It is attributed to the isobutane . O-2 contact charge-transfer absorption, whose onset is shifted from the UV into the visible region by the high electrostatic field of the zeolite. RP Blatter, F (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CALVIN LAB,STRUCT BIOL DIV,BERKELEY,CA 94720, USA. NR 27 TC 31 Z9 32 U1 0 U2 3 PU VCH PUBLISHERS INC PI DEERFIELD BEACH PA 303 NW 12TH AVE, DEERFIELD BEACH, FL 33442-1788 SN 0947-6539 J9 CHEM-EUR J JI Chem.-Eur. J. PD APR PY 1996 VL 2 IS 4 BP 385 EP 389 DI 10.1002/chem.19960020406 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA UM038 UT WOS:A1996UM03800003 ER PT J AU Eylem, C Hriljac, JA Ramamurthy, V Corbin, DR Parise, JB AF Eylem, C Hriljac, JA Ramamurthy, V Corbin, DR Parise, JB TI Structure of a zeolite ZSM-5-bithiophene complex as determined by high-resolution synchrotron X-ray powder diffraction SO CHEMISTRY OF MATERIALS LA English DT Article ID RESONANCE RAMAN-SPECTROSCOPY; NONLINEAR OPTICAL-MATERIALS; ORTHORHOMBIC FRAMEWORK; AROMATIC-MOLECULES; CRYSTAL SYMMETRY; TRANSITION; ZSM-5; THIOPHENE; INTERLAYER; INCLUSION AB The structure of a zeolite ZSM-5 complex with ca. 4 molecules/unit cell of bithiophene was determined by high-resolution synchrotron X-ray powder diffraction. It adopts monoclinic symmetry in space group P2(1)/n (a unique) between room temperature and 25 K, with refined lattice parameters at 25 K of a = 20.0614(4), b = 19.8251(4), c = 13.3623(4) Angstrom, and alpha = 90.848(2)degrees. Structural modeling and Rietveld refinements showed that there are two crystallographically unique bithiophene molecules, each with an occupancy factor of ca. 0.5. One bithiophene is localized at the center of the straight channels with one of the rings residing at the intersection with the sinusoidal channels. The other molecule lies in the sinusoidal channels and projects partially into the straight channels. The relationship between polythiophene chain length and the formation of conducting polythiophene molecular wires in the ZSM-5 framework is discussed. C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. DUPONT CO INC,CENT RES & DEV,WILMINGTON,DE 19880. SUNY STONY BROOK,EARTH & SPACE SCI,STONY BROOK,NY 11794. NR 46 TC 8 Z9 8 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD APR PY 1996 VL 8 IS 4 BP 844 EP 849 DI 10.1021/cm9504495 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA UF852 UT WOS:A1996UF85200008 ER PT J AU Wedman, DE Martinez, HE Nelson, TO AF Wedman, DE Martinez, HE Nelson, TO TI Electrolyte radioactive contamination away SO CHEMTECH LA English DT Article C1 LOS ALAMOS NATL LAB,ENGN SCI APPLICAT DIV,LOS ALAMOS,NM 87545. RP Wedman, DE (reprint author), LOS ALAMOS NATL LAB,DIV NUCL MAT TECHNOL,LOS ALAMOS,NM 87545, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD APR PY 1996 VL 26 IS 4 BP 26 EP 29 PG 4 WC Chemistry, Applied SC Chemistry GA UD767 UT WOS:A1996UD76700009 ER PT J AU Dziewinski, J Marczak, S Smith, W AF Dziewinski, J Marczak, S Smith, W TI Electrochemical destruction of mixed wastes SO CHEMTECH LA English DT Article ID OXIDATION; CYANIDE RP Dziewinski, J (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,NUCL MAT TECHNOL GRP,CST-18,POB 1663,LOS ALAMOS,NM 87545, USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD APR PY 1996 VL 26 IS 4 BP 30 EP 33 PG 4 WC Chemistry, Applied SC Chemistry GA UD767 UT WOS:A1996UD76700010 ER PT J AU Hightower, MM AF Hightower, MM TI EPA speeds technology implementation SO CHEMTECH LA English DT Article RP Hightower, MM (reprint author), SANDIA NATL LABS,ENVIRONM PROGRAMS CTR,TECH STAFF,ALBUQUERQUE,NM 87185, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD APR PY 1996 VL 26 IS 4 BP 73 EP 75 PG 3 WC Chemistry, Applied SC Chemistry GA UD767 UT WOS:A1996UD76700017 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI The order parameter in HTSC SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID HIGH-TEMPERATURE SUPERCONDUCTIVITY; VANHOVE SINGULARITIES; FERMI-SURFACE; BI2SR2CACU2O8+DELTA AB A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short -range repulsion of Hund's or spin-fluctuation origin. This permits to explain the large values of T-c, features of the isotope effect, photoemission results for the gap and the seemingly conflicting results of Josephson experiments in various geometries. The influence of impurity scattering on T-c, the order parameter at T = 0 and the density of states, including the energy gap, are studied for the same model. It is shown that the suppression of the gap in the vicinities of the singularities is weak, and the same is true for T-c. Since the order parameter beyond the singularity is still defined by its value in the singular region, it scales with this value and varies only slightly. However, the energy gap in this region, which does not coincide with the order parameter, varies rapidly with impurity concentration, and the gap becomes isotropic in the strong scattering limit. These conclusions agree with preliminary experimental observations. RP Abrikosov, AA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 184 EP 194 PN 2 PG 11 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800004 ER PT J AU Klemm, RA Ledvij, M Liu, SH AF Klemm, RA Ledvij, M Liu, SH TI Surface state and normal layer effects SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID A-B PLANE; ELECTRONIC-STRUCTURE; SINGLE-CRYSTALS; TEMPERATURE-DEPENDENCE; HIGH-TC; SUPERCONDUCTORS; BI2SR2CACU2O8; ANISOTROPY; HEAT; CU AB In addition to the conducting CuO2(S) layers, most high-T-c superconductors also contain other conducting (N) layers, which are only superconducting due to the proximity effect. The combination of S and N layers can give rise to complicated electronic densities of states, leading to quasilinear penetration depth and NMR relaxation rate behavior at low temperatures. Surface states can also complicate the analysis of tunneling and photoemission measurements. Moreover, geometrical considerations and inhomogeneously trapped flux are possible explanations of the paramagnetic Meissner effect and of corner and ring SQUID experiments. Hence, all of the above experiments could be consistent with isotropic s-wave superconductivity within the S layers. C1 UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. RP Klemm, RA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 54 TC 3 Z9 3 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 201 EP 211 PN 2 PG 11 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800006 ER PT J AU Clem, JR Benkraouda, M Pe, T McDonald, J AF Clem, JR Benkraouda, M Pe, T McDonald, J TI Penetration of magnetic flux and electrical current density into superconducting strips and disks SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID II SUPERCONDUCTORS; CRITICAL-STATE; THIN-FILMS; MAGNETOOPTIC TECHNIQUES; SHAPED SUPERCONDUCTORS; TRANSPORT CURRENTS; SINGLE-CRYSTALS; FLOW NOISE; FIELD; MICROSCOPY AB It has been known for over 30 years how to calculate magnetic-flux-density and current-density profiles in the critical state of type-II superconducting slabs and cylinders subjected to parallel applied magnetic fields. These profiles, which are parameterized by the critical current density J(c), are dependent on magnetic history. Recent theoretical developments have now made it possible to easily calculate the critical-state magnetic-flux-density and current-density profiles associated with vortex penetration into thin superconducting strips and disks subjected to perpendicular applied magnetic fields and transport currents. In this paper we briefly review what has been done in superconducting strips and disks, discuss the detailed behavior for a strip in an increasing applied perpendicular magnetic field, compare these results with those for a slab in an increasing parallel field, and finally present results for the measuring-circuit geometry dependence of the apparent hysteretic losses for a strip carrying an alternating current. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Clem, JR (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 52 TC 13 Z9 13 U1 0 U2 1 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 284 EP 290 PN 2 PG 7 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800018 ER PT J AU Zhang, K Mogilevsky, R Hinks, DG Mitchell, J Shiloh, M Wang, Y StLouisWeber, M AF Zhang, K Mogilevsky, R Hinks, DG Mitchell, J Shiloh, M Wang, Y StLouisWeber, M TI La2-xSrxCuO4 crystal growth by float zone refining technique SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C AB High quality single crystals of La2-xSrxCuO4 (x = 0.15,0.20) have been successfully grown using the floating zone method. Stoichiometric feed rods were prepared with a density high enough for directly zone refining. The chemical composition of the molten zone was allowed to establish itself during the first few zone passes, no off stoichiometric solvent rod was used. Electron microscopy, x-ray back reflection Laue, scanning electron microscopy (SEM), resistivity and ac susceptibility data were used to characterize the crystals. C1 UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT MAT SCI,EVANSTON,IL 60439. RP Zhang, K (reprint author), UNIV CHICAGO,SCI & TECHNOL CTR SUPERCONDUCT,CHICAGO,IL 60637, USA. NR 6 TC 0 Z9 1 U1 0 U2 1 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 315 EP 319 PN 2 PG 5 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800023 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI Some consequences of the layered structure of HTSC SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID HIGH-TEMPERATURE SUPERCONDUCTORS; VALENCE-BOND STATE; TUNNELING CONDUCTANCE; NORMAL TRANSPORT; DIAGNOSTICS; GAP AB The S-N model for high T-c superconductors is briefly described and some inadequacy is mentioned for BTSC containing no CuO chains between the CuO2 planes. A theory is presented for the static c-axis conductivity and superconductivity for such superconductors and compared with experimental data on YBCO with varying oxygen concentration. The basis is the assumption that the hopping of electrons between the CuO2 planes is due to resonant tunneling through localized centers between the planes, and the amplitudes for different centers having the same energy are coherent. The dependence of the normal conductivity on temperature and concentration of resonant centers is calculated. Comparison with experiment shows reasonable agreement. From the obtained dependence of the concentration of resonant centers on the oxygen concentration it can be concluded that these centers disappear simultaneously with holes in the valence band, and hence both originate from the same impurity states with energies below the top of the valence band, which disappear at a certain doping. The supercurrent in the superconducting state proves to be of the Josephson type. The critical value is defined as function of temperature and concentration of resonant centers. Its magnitude is estimated to be J(c) similar to 10(5) - 10(7) A/cm(2). RP Abrikosov, AA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 0 Z9 0 U1 1 U2 1 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 330 EP 339 PN 2 PG 10 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800026 ER PT J AU Clarke, J Dantsker, E Kleiner, R Koelle, D Miklich, AH Ludwig, F AF Clarke, J Dantsker, E Kleiner, R Koelle, D Miklich, AH Ludwig, F TI Progress in high-T-c dc SQUIDs SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID 1/F NOISE; MAGNETOMETER; JUNCTIONS; LAYERS AB This paper reviews the development of magnetometers based on de Superconducting Quantum Interference Devices (SQUIDs) fabricated from thin films of YBa2Cu3O7-x (YBCO) and operated in liquid nitrogen at 77 K. The directly coupled magnetometer consists of a single layer of YBCO deposited on a SrTiO3 (STO) bicrystal patterned so that a pickup loop is connected to the body of the SQUID. These magnetometers achieve a magnetic field noise of under 100 fT Hz(-1/2) at frequencies down to below 1 Hz; the sensitivity may be improved by a factor of 3 or more by inductively coupling the device to a single-layer flux transformer on a 50 mm-diameter substrate. The process for depositing YBCO-STO-YBCO multilayers is reviewed. A fractional turn SQUID involving 16 loops and only 7 mm in diameter exhibited a magnetic field noise of 18 fT Hz(-1/2) at 1 kHz and 37 fT Hz(-1/2) at 1 Hz. A multilayer, multiturn flux transformer magnetically coupled to a SQUID in a flip-chip arrangement achieved a magnetic field noise of 8.5 fT Hz(-1/2) at 1 kHz and 27 fT Hz(-1/2) at 1 Hz; the area of the pickup loop was 10 x 10 mm(2). C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV SCI MAT, BERKELEY, CA 94720 USA. RP UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. RI Koelle, Dieter/E-5111-2011 NR 36 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 352 EP 363 PN 2 PG 12 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800029 ER PT J AU Johnston, DC Borsa, F Cho, BK Canfield, PC Dervenagas, P Goldman, AI Harmon, BN Miller, LL Stassis, C Suh, BJ Torgeson, DR Xu, M Zarestky, J Hundley, MF Movshovich, R Thompson, JD Chubukov, AV Sternlieb, B AF Johnston, DC Borsa, F Cho, BK Canfield, PC Dervenagas, P Goldman, AI Harmon, BN Miller, LL Stassis, C Suh, BJ Torgeson, DR Xu, M Zarestky, J Hundley, MF Movshovich, R Thompson, JD Chubukov, AV Sternlieb, B TI Superconducting and normal state magnetic properties of RNi(2)B(2)C single crystals SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C AB Our studies of the magnetic properties of RNi(2)B(2)C single crystals (R = Y, Gd-Tm, Lu) are reviewed. Of particular interest are the ordered magnetic structures when R is a magnetic rare earth atom, the interaction between magnetism and superconductivity, the influence of crystalline electric fields on the magnetic rare earth ions with resultant effects on these behaviors, and the magnetic character of the Ni sublattice. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV WISCONSIN,MADISON,WI 53706. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Johnston, DC (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Canfield, Paul/H-2698-2014 NR 39 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 397 EP 405 PN 2 PG 9 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800035 ER PT J AU Jeong, GT Kye, JI Chun, SH Park, WK Khim, ZG Lee, WC Canfield, PC Cho, BK Johnston, DC AF Jeong, GT Kye, JI Chun, SH Park, WK Khim, ZG Lee, WC Canfield, PC Cho, BK Johnston, DC TI Tunneling measurement for the energy gap in quaternary compound superconductors YNi2B2C, LuNi2B2C and YBCO by LTSTM SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID CU-O; SPECTROSCOPY AB Tunneling spectra of a single crystalline YNi2B2C (T-c = 15.4 K), LuNi2B2C (T-c = 15.7 K) and YBCO (T-c = 90 K) have been measured by a point contact spectroscopy using a low temperature scanning tunneling microscope. The conductance curve of RNi(2)B(2)C shows a smeared gap structure with an almost linear density of states inside of the gap region. The linear conductance inside the gap region has been explained by a proximity induced energy gap in the degraded surface normal layer. c-axis oriented YBCO films shows periodic current steps at the corresponding voltage of V = (2n+1)V-0. Voltage period Delta V shows a dependence on the sample-to-tip distance implying the single electron tunneling nature. C1 SOOKMYUNG WOMENS UNIV,DEPT PHYS,SEOUL 140742,SOUTH KOREA. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Jeong, GT (reprint author), SEOUL NATL UNIV,DEPT PHYS,SEOUL 151742,SOUTH KOREA. RI Canfield, Paul/H-2698-2014; OI Chun, Seung-Hyun/0000-0001-8397-4481 NR 16 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 406 EP 413 PN 2 PG 8 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800036 ER PT J AU Wang, YL Bian, W Zhu, Y Suenaga, M Thurston, TR AF Wang, YL Bian, W Zhu, Y Suenaga, M Thurston, TR TI Powder synthesis and fabrication of Ag-sheathed Bi-2223 tapes SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID PHASE AB An alternate processing route is described for the production of uniform, fine-grained precursor mixture for the fabrication of Bi-2223 tapes. The precursor powder was produced by aerosol spray pyrolysis of nitrate salts. It was found that the phase content of the powder is sensitive to several processing parameters including temperature and oxygen partial pressure. Bi-2223 tapes were manufactured using these powders by a powder-in-tube method. Supereonducting properties of these tapes are presented. A novel nondestructive transmission x-ray diffraction study showed that the texturing process of the superconducting phase is nearly complete by the end of very early stage of heat treatment. Pressing was found to play little rote for the texturing process. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Wang, YL (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 466 EP 470 PN 2 PG 5 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800045 ER PT J AU Maple, MB Herrmann, J deAndrade, MC Almasan, CC Han, SH Gajewski, DA Paulius, LM Jiang, W Mao, SN Greene, RL Paulikas, AP Gu, C Veal, BW AF Maple, MB Herrmann, J deAndrade, MC Almasan, CC Han, SH Gajewski, DA Paulius, LM Jiang, W Mao, SN Greene, RL Paulikas, AP Gu, C Veal, BW TI Magnetoresistance and Hall effect study of electron- and hole-doped cuprate superconductors SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 1995 Taiwan International Conference on Superconductivity (TICS 95) CY AUG 08-11, 1995 CL HUALIEN, TAIWAN SP Natl Tsing Hua Univ, Dept Phys & Mat Sci Ctr R O C, Natl Sci Council R O C, Minist Educ R O C, Phys Soc R O C, Natl Hualien Teachers Coll R O C, Ind Technol Res Inst R O C ID II SUPERCONDUCTORS; SINGLE-CRYSTALS; FLUCTUATIONS; TRANSITIONS; TRANSPORT AB Hall effect measurements on single crystals of the hole-doped systems Y1-xPrxBa2Cu3O7-delta(delta approximate to 0.05) and YBa2Cu3Oy as a function of x and y, respectively, y showed that the Hall conductivity sigma(xy) vs B data in the mixed state could be described by the expression sigma(xy) = C-1/B + C2B, where the two terms are associated with motion of the magnetic vortices and the quasi-particles in the vortex cores, respectively, and the parameters C-1 and C-2 are functions of x, y, and T. Magnetoresistance measurements on epitaxial thin films of the electron-doped superconductor Nd1.85Ce0.15CuO4+/-delta with varying oxygen content in magnetic fields B parallel to c revealed (a) critical scaling of the electrical resistivity data consistent with a vortex-glass transition for a film with an optimum T-c approximate to 22 K and (b) a characteristic anomaly that develops with increasing field for T < 2 K for an over-oxygenated film with T-c approximate to 10 K. C1 UNIV MARYLAND, CTR SUPERCONDUCT RES, COLLEGE PK, MD 20742 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RP UNIV CALIF SAN DIEGO, INST PURE & APPL PHYS SCI, LA JOLLA, CA 92093 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 1996 VL 34 IS 2 BP 471 EP 478 PN 2 PG 8 WC Physics, Multidisciplinary SC Physics GA UK968 UT WOS:A1996UK96800046 ER PT J AU Fendorf, S Fendorf, M AF Fendorf, S Fendorf, M TI Sorption mechanisms of lanthanum on oxide minerals SO CLAYS AND CLAY MINERALS LA English DT Article DE electron microscopy; lanthanum; metal-oxides; sorption ID HYDROLYZABLE METAL-IONS; WATER INTERFACE; ADSORPTION; OXIDATION; SURFACES; MODEL AB The retention of hazardous species, including many of the lanthanides, on soils and sediments is vital for maintaining environmental quality. In this study, high-resolution transmission electron microscopy (HRTEM) was used to identify surface precipitates of La and their degree of atomic ordering on oxides of Mn (birnessite), Fe (goethite) and Ti (rutile) over a pH range of 3 to 8. At pH > 5.5, the aqueous concentration of La was fully depleted by all three metal-oxides. On birnessite, surface precipitation of La-hydroxide occurred at pH greater than or equal to 5 and appears to be the dominant sorption mechanism on this mineral. Surface precipitation was not observed on rutile or goethite until much higher pH values, 6.5 for rutile and 8.0 for goethite. Precipitation is thus correlated with the points of zero charge (PZC) of the minerals, 6.3 for rutile and 7.8 for goethite, and in each case was observed only at pH values above the PZC. Although La sorption was extensive on all of the minerals at the higher pHs, the depletion of La from solution by rutile and goethite at pH values well below the PZC indicates that the sorption mechanism differs from that on birnessite. While surface precipitation was found to be the dominant sorption mechanism of La on birnessite, surface complexation of monomeric or small multinuclear species appears to predominate in La retention on rutile and goethite at most commonly encountered pH values. RP Fendorf, S (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, NATL CTR ELECTRON MICROSCOPY, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 16 TC 10 Z9 10 U1 1 U2 3 PU CLAY MINERALS SOC PI CHANTILLY PA 3635 CONCORDE PKWY, STE 500, CHANTILLY, VA 20151-1125 USA SN 0009-8604 EI 1552-8367 J9 CLAY CLAY MINER JI Clay Clay Min. PD APR PY 1996 VL 44 IS 2 BP 220 EP 227 DI 10.1346/CCMN.1996.0440207 PG 8 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA UL994 UT WOS:A1996UL99400007 ER PT J AU Slingo, JM Sperber, KR Boyle, JS Ceron, JP Dix, M Dugas, B Ebisuzaki, W Fyfe, J Gregory, D Gueremy, JF Hack, J Harzallah, A Inness, P Kitoh, A Lau, WKM McAvaney, B Madden, R Matthews, A Palmer, TN Park, CK Randall, D Renno, N AF Slingo, JM Sperber, KR Boyle, JS Ceron, JP Dix, M Dugas, B Ebisuzaki, W Fyfe, J Gregory, D Gueremy, JF Hack, J Harzallah, A Inness, P Kitoh, A Lau, WKM McAvaney, B Madden, R Matthews, A Palmer, TN Park, CK Randall, D Renno, N TI Intraseasonal oscillations in 15 atmospheric general circulation models: Results from an AMIP diagnostic subproject SO CLIMATE DYNAMICS LA English DT Article ID OUTGOING LONGWAVE RADIATION; 30-60 DAY OSCILLATION; WESTERN PACIFIC; ANGULAR-MOMENTUM; NORTHERN WINTER; CONVECTION; ANOMALIES; CLUSTERS; TROPICS; OCEAN AB The ability of 15 atmospheric general circulation models (AGCM) to simulate the tropical intraseasonal oscillation has been studied as part of the Atmospheric Model Intercomparison Project (AMIP). Time series of the daily upper tropospheric velocity poential and zonal wind, averaged over the equatorial belt, were provided from each AGCM simulation. These data were analyzed using a variety of techniques such as time filtering and space-time spectral analysis to identify eastward and westward moving waves. The results have been compared with an identical assessment of the European Centre for Medium-range Weather Forecasts (ECMWF) analyses for the period 1982-1991. The models display a wide range of skill in simulating the intraseasonal oscillation. Most models show evidence of an eastward propagating anomaly in the velocity potential field, although in some models there is a greater tendency for a standing oscillation, and in one or two the field is rather chaotic with no preferred direction of propagation. Where a model has a clear eastward propagating signal, typical periodicities seem quite reasonable although there is a tendency for the models to simulate shorter periods than in the ECMWF analyses, where it is near 50 days. The results of the space-time spectral analysis have shown that no model has captured the dominance of the intraseasonal oscillation found in the analyses. Several models have peaks at intraseasonal time scales, but nearly all have relatively more power at higher frequencies (<30 days) than the analyses. Most models underestimate the strength of the intraseasonal variability. The observed intraseasonal oscillation shows a marked seasonality in its occurrence with greatest activity during northern winter and spring. Most models failed to capture this seasonality. The interannual variability in the activity of the intraseasonal oscillation has also been assessed, although the AMIP decade is too short to provide any conclusive results. There is a suggestion that, the observed oscillation was suppressed during the strong El Nino of 1982/83, and this relationship has also been reproduced by some models. The relationship between a model's intraseasonal activity, its seasonal cycle and characteristics of its basic climate has been examined. It is clear that those models with weak intraseasonal activity tend also to have a weak seasonal cycle. It is becoming increasingly evident that an accurate description of the basic climate may be a prerequisite for producing a realistic intraseasonal. In particular, models with the most realistic intraseasonal oscillations appear to have precipitation distributions which are better correlated with warm sea surface temperatures. These models predominantly employ convective parameterizations which are closed on buoyancy rather than moisture convergence. C1 LAWRENCE LIVERMORE NATL LAB,PROGRAM CLIMATE MODEL DIAGNOSIS & INTERCOMPARISON,LIVERMORE,CA 94551. METEO FRANCE,ECOLE NATL METEOROL,F-31057 TOULOUSE,FRANCE. CSIRO,DIV ATMOSPHER RES,MORDIALLOC,VIC 3195,AUSTRALIA. NOAA,NMC,CAMP SPRINGS,MD 20746. UNIV VICTORIA,CANADIAN CLIMATE CTR,VICTORIA,BC V8W 2Y2,CANADA. UK METEOROL OFF,HADLEY CTR CLIMATE PREDICT & RES,BRACKNELL RG12 2SY,BERKS,ENGLAND. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. ECOLE NORMALE SUPER,CNRS,METEOROL DYNAM LAB,F-75231 PARIS 05,FRANCE. METEOROL RES INST,TSUKUBA,IBARAKI 305,JAPAN. BUR METEOROL RES CTR,MELBOURNE,VIC 3001,AUSTRALIA. EUROPEAN CTR MEDIUM RANGE WEATHER FORECASTS,READING RG2 9AX,BERKS,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,DATA ASSIMILAT OFF,GREENBELT,MD 20771. COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523. CALTECH,PASADENA,CA 91125. RP Slingo, JM (reprint author), UNIV READING,DEPT METEOROL,2 EARLEY GATE,READING RG6 6AU,BERKS,ENGLAND. RI Matthews, Adrian/A-6444-2011; Dix, Martin/A-2334-2012; Sperber, Kenneth/H-2333-2012; Randall, David/E-6113-2011; Lau, William /E-1510-2012 OI Matthews, Adrian/0000-0003-0492-1168; Dix, Martin/0000-0002-7534-0654; Randall, David/0000-0001-6935-4112; Lau, William /0000-0002-3587-3691 NR 45 TC 392 Z9 424 U1 3 U2 15 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD APR PY 1996 VL 12 IS 5 BP 325 EP 357 DI 10.1007/BF00231106 PG 33 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UF608 UT WOS:A1996UF60800003 ER PT J AU Urtiew, PA Tarver, CM Maienschein, JL Tao, WC AF Urtiew, PA Tarver, CM Maienschein, JL Tao, WC TI Effect of confinement and thermal cycling on the shock initiation of LX-17 SO COMBUSTION AND FLAME LA English DT Article AB The shock initiation of the insensitive high explosive LX-17, which contains 92.5% triaminotrinitrobenzene (TATB) and 7.5% Kel-F binder, was studied under two simulated accident conditions: initially confined charges were heated to 250 degrees C and shocked; and unconfined charges were thermally cycled between 25 degrees and 250 degrees C and shocked. Previous research on unconfined TATE-based explosives heated to 250 degrees C revealed increased shock sensitivity. This increase was attributed to both the increased porosity caused by the unsymmetrical thermal expansion of TATB, which resulted in more hotspot ignition sites, and the faster growth of hot spot reactions due to the increased surrounding temperature. In this study, aluminum confinement was used to decrease the thermal expansion of LX-17. The shock sensitivity of confined LX-17 at 250 degrees C was observed to be less than that of unconfined charges at 250 degrees C but greater than that of unconfined, ambient temperature LX-17. The thermal cycling results showed that the LX-17 heated to 250 degrees C and then shocked at 25 degrees C was more sensitive than pristine LX-17, because irreversible growth had produced more ignition Sites. LX-17 held at 250 degrees C for an hour or fired at 250 degrees C after two thermal cycles did not appear to be significantly more shock sensitive than LX-17 heated to 250 degrees C and shocked immediately. Therefore it is unlikely that TATE is thermally decomposing into less stable intermediate species at 250 degrees C. The Ignition and Growth reactive flow model for shock initiation of LX-17 was normalized to these experimental results to provide a predictive capability for other accident scenarios that cannot be tested directly. C1 LAWRENCE LIVERMORE NATL LAB,ENERGET MAT CTR L282,LIVERMORE,CA 94551. NR 19 TC 15 Z9 19 U1 2 U2 5 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 APR PY 1996 VL 105 IS 1-2 BP 43 EP 53 DI 10.1016/0010-2180(95)00178-6 PG 11 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA UC913 UT WOS:A1996UC91300005 ER PT J AU Tarver, CM Urtiew, PA Tao, WC AF Tarver, CM Urtiew, PA Tao, WC TI Shock initiation of a heated ammonium perchlorate-based propellant SO COMBUSTION AND FLAME LA English DT Article AB Solid propellants containing ammonium perchlorate (AP), aluminum, and a carboxylterminated polybutadiene binder (CTPB) are known to burn reliably and to be very insensitive to transition to detonation under ambient conditions. In accident scenarios, these propellants may become more shock sensitive when they are subjected to heat and/or multiple impacts. The shock sensitivity of one such propellant, ANB-3066, is determined using embedded manganin pressure gauges at an elevated temperature of 170 degrees C. The measured pressure histories are modeled using the Ignition and Growth reactive flow model of shock initiation and detonation. The experiments clearly show that ANB-3066 is not significantly more shock sensitive at 170 degrees C than it is at ambient temperature. The Ignition and Growth reactive flow calculations indicate that less than 20% of the chemical energy of AP and CTPB reactions is released at input shock pressures as high as 21 GPa. The aluminum component does not reach the high temperatures required for it to react. These results indicate that AP-based solid propellants are still extremely resistant to shock to detonation transition even when heated to temperatures close to the thermal decomposition temperature of the propellant formulation. The shock insensitivity of heated AP-based propellants is hypothesized to be due to the melting of the AP component during shock loading and the relatively low temperatures produced by the weakly exothermic decomposition of AP and binder. RP Tarver, CM (reprint author), LAWRENCE LIVERMORE NATL LAB,ENERGET MAT CTR L282,LIVERMORE,CA 94550, USA. NR 32 TC 6 Z9 6 U1 1 U2 5 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 APR PY 1996 VL 105 IS 1-2 BP 123 EP 131 DI 10.1016/0010-2180(95)00181-6 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA UC913 UT WOS:A1996UC91300011 ER PT J AU Moser, LE MelliarSmith, PM Agarwal, DA Budhia, RK LingleyPapadopoulos, CA AF Moser, LE MelliarSmith, PM Agarwal, DA Budhia, RK LingleyPapadopoulos, CA TI Totem: A fault-tolerant multicast group communication system SO COMMUNICATIONS OF THE ACM LA English DT Article ID TIME C1 LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. TANDEM COMP INC, CUPERTINO, CA 95014 USA. RP UNIV CALIF SANTA BARBARA, DEPT ELECT & COMP ENGN, SANTA BARBARA, CA 93016 USA. NR 18 TC 184 Z9 192 U1 0 U2 2 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0001-0782 EI 1557-7317 J9 COMMUN ACM JI Commun. ACM PD APR PY 1996 VL 39 IS 4 BP 54 EP 63 DI 10.1145/227210.227226 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA UC438 UT WOS:A1996UC43800021 ER PT J AU Miyama, M Kumano, S AF Miyama, M Kumano, S TI Numerical solution of Q(2) evolution equations in a brute-force method SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE structure function; parton distribution; Q(2) evolution; numerical solution ID DEEP-INELASTIC-SCATTERING; FREE GAUGE-THEORIES; PROTON STRUCTURE FUNCTIONS; LEADING ORDER; WILSON OPERATORS; LAGUERRE METHOD; SMALL VALUES; QCD; RECOMBINATION; DISTRIBUTIONS AB We investigate the numerical solution of Q(2) evolution equations for structure functions in the nucleon and in nuclei. (Dokshitzer-Gribov-Lipatov-) Altarelli-Parisi and Mueller-Qiu evolution equations are solved in a brute-force method. Spin-independent flavor-nonsinglet and singlet equations with next-to-leading-order alpha(s) corrections are studied. Dividing the variables x and Q(2) into small steps, we simply solve the integrodifferential equations. Numerical results indicate that accuracy is better than 2% in the region 10(-4) < x < 0.8 if more than two-hundred Q(2) steps and more than one-thousand x steps are taken. The numerical solution is discussed in detail, and evolution results are compared with Q(2) dependent data in CDHSW SLAG, BCDMS, EMC, NMC, Fermilab-E665, ZEUS, and H1 experiments. We provide a FORTRAN program for Q(2) evolution (and ''devolution'') of nonsinglet-guark, singlet-quark, q(i) + q(i), and gluon distributions (and corresponding structure functions) in the nucleon and in nuclei. This is a very useful program for studying spin-independent structure functions. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Miyama, M (reprint author), SAGA UNIV,DEPT PHYS,SAGA 840,JAPAN. NR 47 TC 97 Z9 98 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD APR PY 1996 VL 94 IS 2-3 BP 185 EP 215 DI 10.1016/0010-4655(96)00013-6 PG 31 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA UF609 UT WOS:A1996UF60900005 ER PT J AU Holling, CS Meffe, GK AF Holling, CS Meffe, GK TI Command and control and the pathology of natural resource management SO CONSERVATION BIOLOGY LA English DT Article ID ECOSYSTEMS; SCALE AB As the human population grows and natural resources decline, there is pressure to apply increasing levels of top-down, command-and-control management to natural resources. This is manifested in attempts to control ecosystems and in socioeconomic institutions that respond to erratic or surprising ecosystem behavior with more control. Command and control, however, usually results in unforeseen consequences for both natural ecosystems and human welfare in the form of collapsing resources, social and economic strife, and losses of biological diversity. We describe the ''pathology of natural resource management,'' defined as a loss of system resilience when the range of natural variation in the system is reduced encapsulates the unsustainable environmental, social, and economic outcomes of command-and-control resource management. If natural levels of variation in system behavior are reduced through command-and-control, then the system becomes less resilient to external perturbations, resulting in crises and surprises. We provide several examples of this pathology in management. An ultimate pathology emerges when resource management agencies, through initial success with command and control, lose sight of their original purposes, eliminate research and monitoring, and focus on efficiency of control. They then become isolated from the managed systems and inflexible in structure. Simultaneously, through overcapitalization, society becomes dependent upon command and control, demands it in greater intensity, and ignores the underlying ecological change or collapse that is developing. Solutions to this pathology cannot come from further command and control (regulations) but must come from innovative approaches involving incentives leading to more resilient ecosystems, more flexible agencies, more self-reliant industries, and a more knowledgeable citizenry. We discuss several aspects of ecosystem pattern and dynamics at large scales that provide insight into ecosystem resilience, and we propose a ''Golden Rule'' of natural resource management that we believe is necessary for sustainability: management should strive to retain critical types and ranges of natural variation in resource systems in order to maintain their resiliency. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. UNIV FLORIDA,DEPT ZOOL,GAINESVILLE,FL 32611. NR 53 TC 708 Z9 741 U1 22 U2 212 PU BLACKWELL SCIENCE INC PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD APR PY 1996 VL 10 IS 2 BP 328 EP 337 DI 10.1046/j.1523-1739.1996.10020328.x PG 10 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA UK801 UT WOS:A1996UK80100013 ER PT J AU Kahn, O Payne, S AF Kahn, O Payne, S TI Optical and magnetic materials - Editorial overview SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Editorial Material C1 LAWRENCE LIVERMORE NATL LAB,LASER PROGRAM,LIVERMORE,CA 94551. RP Kahn, O (reprint author), ICNCB,LAB SCI MOL,AVE DOCTEUR SCHWEITZER,F-33608 PESSAC,FRANCE. NR 0 TC 0 Z9 0 U1 1 U2 1 PU CURRENT SCIENCE LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 1359-0286 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD APR PY 1996 VL 1 IS 2 BP 175 EP 176 DI 10.1016/S1359-0286(96)80080-5 PG 2 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA VE414 UT WOS:A1996VE41400001 ER PT J AU Bench, GS Friz, AM Corzett, MH Morse, DH Balhorn, R AF Bench, GS Friz, AM Corzett, MH Morse, DH Balhorn, R TI DNA and total protamine masses in individual sperm from fertile mammalian subjects SO CYTOMETRY LA English DT Article DE sperm; protamine 1; protamine 2; DNA; Particle Induced X-ray Emission (PIXE); electrophoresis; microdensitometry; histones; binding site ID AMINO-ACID-SEQUENCE; NUCLEAR BASIC-PROTEINS; MAJOR PROTAMINE; MOUSE SPERM; 2 FORMS; SPERMATOZOA; CHROMATIN; CELLS; RAT AB The total amount of phosphorus and sulfur inside the nuclei of individual bull, stallion, hamster, human, and mouse sperm from fertile subjects has been measured using Particle Induced X-ray Emission (PIXE), Using the sulfur masses, we determined the total protamine (protamine 1 plus protamine 2) mass within the sperm nuclei of each species, Using the phosphorus masses, we determined the DNA mass present within the sperm nuclei of each species, The results reveal that although the relative proportion of protamine 1 to protamine 2 varies among the species examined, the total protamine mass to DNA mass ratio is similar in bull, stallion, hamster, and mouse sperm nuclei, In contrast, mature human sperm nuclei were found to contain significantly less protamine, This observation is consistent with other studies, which suggest that as much as 15% of the DNA in human sperm remain packaged by histones. Using the data obtained for bull sperm, the length of DNA that could be covered by each protamine 1 molecule in bull sperm has been estimated, Making the assumption that the size of the protamine 1 binding site on DNA is similar in the sperm of these species, the length of DNA covered by a single protamine 2 molecule also has been estimated. (C) 1996 Wiley-Liss, Inc. C1 LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94550. SANDIA NATL LABS,LIVERMORE,CA. RP Bench, GS (reprint author), LAWRENCE LIVERMORE NATL LAB,CTR ACCELERATOR MASS SPECTROMETRY,L-397,LIVERMORE,CA 94550, USA. NR 40 TC 97 Z9 101 U1 2 U2 12 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0196-4763 J9 CYTOMETRY JI Cytometry PD APR 1 PY 1996 VL 23 IS 4 BP 263 EP 271 DI 10.1002/(SICI)1097-0320(19960401)23:4<263::AID-CYTO1>3.0.CO;2-I PG 9 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA UC594 UT WOS:A1996UC59400001 PM 8900468 ER PT J AU Litle, VR Lockett, SJ Pallavicini, MG AF Litle, VR Lockett, SJ Pallavicini, MG TI Genotype phenotype analyses of low frequency tumor cells using computerized image microscopy SO CYTOMETRY LA English DT Article DE image cytometry; immunocytochemistry; fluorescence in situ hybridization; rare tumor cells; micrometastases; aneusomy ID MONOCLONAL-ANTIBODIES; BONE-MARROW; INSITU HYBRIDIZATION; BREAST-CARCINOMA; CANCER; IMMUNOFLUORESCENCE AB Techniques to identify low frequency (i.e., 10(-4)-10(-5)) tumor cells in bone marrow and peripheral blood of cancer patients provide opportunities for early detection of disseminated disease and characterization of the properties of cells released from the tumor, Low frequency epithelial cells in marrow and blood can be detected using immunophenotypic markers directed against intracellular and/or cell surface antigens. However, nonspecific phenotypic labeling may compromise the ability to discriminate tumor from nontumor cells, We describe optimization of slide-based approaches that facilitate identification and subsequent molecular cytogenetic characterization of rare tumor cell populations in hematopoietic tissues, Colon tumor cells seeded in a hematopoietic background provided a model system to optimize methodologies that are applicable to detection and quantification of micrometastases in clinical specimens, Mixtures of cytogenetically aberrant epithelial cells and hematopoietic cells on slides were labeled with an anti-cytokeratin 20 (anti-CK20) antibody that recognizes >90% of colon adenocarcinomas, Computerized image analysis was used to record the location of the immunofluorescent cells on microscopic slides. Cells on slides were then hybridized using fluorescence in situ hybridization (FISH) with repeat-sequence DNA probes to detect aneusomies, Previously discriminated epithelial cells were relocated for molecular cytogenetic characterization. Tumor cells present at frequencies approximating 5 x 10(-5) were discriminated on the basis of immunofluorescence and cell size, A low frequency (4 x 10(-4)) population of normal hematopoietic cells also labeled with anti-CK20 (data not shown). This strategy of sequential immunophenotyping and molecular cytogenetic analyses may be useful to discriminate tumor from nontumor cells in cancer patients with micrometastatic disease. (C) 1996 Wiley-Liss, Inc. C1 UNIV CALIF SAN FRANCISCO,DEPT LAB MED,DIV MOL CYTOMETRY,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT SURG,SAN FRANCISCO,CA 94143. LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA. RI Litle, Virginia/A-9859-2013 OI Litle, Virginia/0000-0002-3107-688X NR 22 TC 13 Z9 14 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 0196-4763 J9 CYTOMETRY JI Cytometry PD APR 1 PY 1996 VL 23 IS 4 BP 344 EP 349 DI 10.1002/(SICI)1097-0320(19960401)23:4<344::AID-CYTO11>3.0.CO;2-T PG 6 WC Biochemical Research Methods; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA UC594 UT WOS:A1996UC59400011 PM 8900478 ER PT J AU Larabell, CA Rowning, BA Wells, J Wu, M Gerhart, JC AF Larabell, CA Rowning, BA Wells, J Wu, M Gerhart, JC TI Confocal microscopy analysis of living Xenopus eggs and the mechanism of cortical rotation SO DEVELOPMENT LA English DT Article DE cortical rotation; Xenopus; microtubule; confocal microscopy ID FERTILIZED FROG EGGS; LAEVIS EGGS; AXIS FORMATION; GREY CRESCENT; MICROTUBULES; SPERM; ORGANIZATION; FLAGELLA; KINESIN; INVITRO AB The dorsoventral body axis in amphibian embryos is established by a rotation of the outer cortex relative to the inner cytoplasmic core. This cortical rotation depends on microtubules and is correlated with a parallel array of microtubules just inside the vegetal cortex, Since the parallel array moves with the inner cytoplasm and most of its microtubules are oriented with their plus ends facing the direction of cortical movement, it has been suggested that plus end-directed motor molecules attached to the cortex drive the rotation by moving along microtubules of the parallel array, Using an inverted confocal microscope to examine living eggs, however, we found that rotation movements precede the formation of a detectable parallel array at the vegetal pole, that the parallel array consists of multiple layers of microtubules at depths ranging from 4 to 8 mu m inside the plasma membrane and that the velocity of rotation in immobilized eggs increases with depth in this region, These findings suggest that (1) early cytoplasmic movements are due to something other than the fully formed parallel array and (2) the motor molecules responsible for the bulk of the rotation movement are not restricted to a monolayer at the subcortical interface but may be distributed throughout the parallel array, perhaps causing microtubules to slide along other microtubules by a mechanism similar to that seen in cilia and eukaryotic flagella. C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720. RP Larabell, CA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. FU NIGMS NIH HHS [GM19363] NR 40 TC 42 Z9 42 U1 0 U2 3 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE, CAMBS, ENGLAND CB4 4DL SN 0950-1991 J9 DEVELOPMENT JI Development PD APR PY 1996 VL 122 IS 4 BP 1281 EP 1289 PG 9 WC Developmental Biology SC Developmental Biology GA UF831 UT WOS:A1996UF83100024 PM 8620855 ER PT J AU Gil, P Green, PJ AF Gil, P Green, PJ TI Multiple regions of the Arabidopsis SAUR-AC1 gene control transcript abundance: The 3' untranslated region functions as an mRNA instability determinant SO EMBO JOURNAL LA English DT Article DE Arabidopsis; auxin; mRNA stability; SAUR ID PROTEIN-SYNTHESIS INHIBITORS; MESSENGER-RNA DEGRADATION; HIGHER-PLANTS; SELECTABLE MARKERS; RAPID DECAY; C-FOS; AUXIN; TOBACCO; EXPRESSION; STABILITY AB The small-auxin-up-RNA (SAUR) transcripts are rapidly induced by auxin and are among the most short-lived mRNAs in higher plants. In this study, we investigate the regulation of SAUR-AC1, a well characterized SAUR gene of Arabidopsis. By examining the expression of chimeric genes in transgenic tobacco, we demonstrate that the promoter region of SAUR-AC1 mediates auxin induction. Sequences downstream of the promoter region were found to limit mRNA accumulation in a manner that was independent of auxin treatment. Both the coding region and the 3' untranslated region (UTR) of SAUR-AC1 independently contribute to this limitation. Effects on mRNA stability were assayed using chimeric genes under the control of the tetracycline-repressible Top10 promoter. mRNA half-life analysis following tetracycline treatment showed that the SAUR-AC1 coding region does not contain elements that decrease mRNA stability. In contrast, the 3' UTR was found to act as a potent mRNA instability determinant. This finding and the general utility of the Top10 system should provide the means to elucidate mRNA decay pathways that are potentially novel and specific for certain unstable transcripts. C1 MICHIGAN STATE UNIV,MSU DOE PLANT RES LAB,E LANSING,MI 48824. NR 38 TC 58 Z9 63 U1 2 U2 4 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0261-4189 J9 EMBO J JI Embo J. PD APR 1 PY 1996 VL 15 IS 7 BP 1678 EP 1686 PG 9 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA UF658 UT WOS:A1996UF65800023 PM 8612592 ER PT J AU Berry, GD Pasternak, AD Rambach, GD Smith, JR Schock, RN AF Berry, GD Pasternak, AD Rambach, GD Smith, JR Schock, RN TI Hydrogen as a future transportation fuel SO ENERGY LA English DT Article AB A smooth transition from a petroleum-driven transportation system to clean-burning automobiles with the performance and range of today's gasoline cars is plausible using high-efficiency hydrogen-fueled hybrid-electric vehicles. The introduction of hydrogen (H-2) vehicles will reduce U.S. dependence on oil imports, virtually eliminate automotive urban air pollution, accelerate the development of cost-effective renewable energy, and help stabilize greenhouse-gas emissions. Based on an economic and technical analysis, H-2 vehicles, when first introduced, can be cost-competitive with battery-powered electric vehicles. As market penetration increases, H-2-vehicle fueling costs would become competitive with the fueling costs of today's gasoline Vehicles (5 cent/mi). Hydrogen production at filling stations, vehicle fleets, and homes would circumvent many start-up issues and would use existing natural gas and/or electricity energy infrastructures to begin the transition towards a clean, flexible, sustainable, and secure transportation fuel. C1 LAWRENCE LIVERMORE NATL LAB,ENERGY PROGRAM,LIVERMORE,CA 94551. NR 47 TC 57 Z9 58 U1 1 U2 14 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 APR PY 1996 VL 21 IS 4 BP 289 EP 303 DI 10.1016/0360-5442(95)00104-2 PG 15 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA UC285 UT WOS:A1996UC28500005 ER PT J AU Hirst, E Cavanagh, R Miller, P AF Hirst, E Cavanagh, R Miller, P TI The future of DSM in a restructured US electricity industry SO ENERGY POLICY LA English DT Article DE DSM; development; US electricity industry AB During the past several years, more and more electric utilities have been running demand-side management (DSM) programmes, These programmes improve the efficiency with which customers use electricity and affect the timing of that use leg to shift it away from high-cost times), Utilities run such programmes for two primary reasons, One is to improve customer service, The second is to acquire resources that, just like power plants, can meet customer energy service needs, DSM programmes often are less expensive and environmentally cleaner than power plants, By 1994, US utility DSM programmes had cut potential summer peak demand by 7% and annual electricity use by 2%, We examine the economics of DSM in the late 1990s, reviewing current estimates of avoided supply costs and the cost of conserved electricity for DSM programmes, We review the environmental effects of electricity production and the environmental benefits of DSM programmes, Finally, we consider alternative electric industry structures and how DSM can operate within these alternatives. (C) 1996 Elsevier Science Ltd. C1 NAT RESOURCES DEF COUNCIL,SAN FRANCISCO,CA 94105. RP Hirst, E (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 42 TC 9 Z9 9 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 APR PY 1996 VL 24 IS 4 BP 303 EP 315 DI 10.1016/0301-4215(95)00139-5 PG 13 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA UJ174 UT WOS:A1996UJ17400004 ER PT J AU Sutherland, RJ AF Sutherland, RJ TI The economics of energy conservation policy SO ENERGY POLICY LA English DT Article DE DSM; conservation; competition ID EFFICIENCY; BARRIERS AB Energy conservation proponents have recently attempted to provide a more rigorous economics justification for both energy appliance standards and utility energy conservation programmes. A tenable case cannot however, be made: market failures do not produce a consistent bias towards energy use; conservation programmes do not reduce the cause of the market failure, and more typically exacerbate market or regulatory failures; and there is no evidence that such programmes make consumers better off in the relevant sense that consumers are willing to pay for them. The development of competitive electricity and gas commodity markets at the end-use level will produce an efficient disposition of utility sponsored programmes. (C) 1996 Elsevier Science Ltd. RP Sutherland, RJ (reprint author), ARGONNE NATL LAB,955 ENFANT PLAZA SW,SUITE 6000,WASHINGTON,DC 20024, USA. NR 36 TC 31 Z9 31 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 APR PY 1996 VL 24 IS 4 BP 361 EP 370 DI 10.1016/0301-4215(95)00136-0 PG 10 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA UJ174 UT WOS:A1996UJ17400009 ER PT J AU Wyatt, DE Temples, TJ AF Wyatt, DE Temples, TJ TI Ground-penetrating radar detection of small-scale channels, joints and faults in the unconsolidated sediments of the Atlantic Coastal Plain SO ENVIRONMENTAL GEOLOGY LA English DT Article DE ground-penetrating radar; unconsolidated sediments; environmental characterization; faulting AB The geological characterization of the shallow subsurface in the unconsolidated sediments of the Atlantic Coastal Plain, and other unconsolidated sediment regimes, may involve jointing, faulting, and channeling not readily detectable by conventional drilling and mapping. A knowledge of these features is required in environmental, geotechnical, and geomorphological studies. Ground-penetrating radar (GPR) may be used to routinely map these structures. Three principal shallow subsurface features are readily detectable using GPR: paleochannels, joints or fractures, and faults. The detection of paleochannels Is dependent on the scale of the GPR survey and the attitude of the channel within the survey area. Channel morphological features such as scour surfaces, point bars, arid thalwegs are observable. Joints and fractures are more difficult to detect depending upon size, patterns, orientation, and fill material. Vertical joints may not be visible to radar unless they are wider than the sampling interval or are filled with radar-opaque materials such as limonite. Angled joints or fractures may be distinguished by an apparent continuous reflector on the radar profile. Faulting on radar profiles may be observed by the offset of reflectors, the image of the fault plane, or the coherent interpretation of a fault system. C1 US DOE,AIKEN,SC 29801. RP Wyatt, DE (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,POB 616,AIKEN,SC 29802, USA. NR 30 TC 12 Z9 12 U1 0 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0177-5146 J9 ENVIRON GEOL JI Environ. Geol. PD APR PY 1996 VL 27 IS 3 BP 219 EP 225 PG 7 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA UJ177 UT WOS:A1996UJ17700010 ER PT J AU Fehner, TR Gosling, FG AF Fehner, TR Gosling, FG TI Coming in from the cold - Regulating US Department of Energy Nuclear Facilities, 1942-96 SO ENVIRONMENTAL HISTORY LA English DT Article RP Fehner, TR (reprint author), US DOE,WASHINGTON,DC 20585, USA. NR 74 TC 2 Z9 2 U1 0 U2 0 PU ENVIRONMENTAL HISTORY PI DURHAM PA 701 VICKERS AVE, DURHAM, NC 27701-3147 SN 1084-5453 J9 ENVIRON HIST JI Environ. Hist. PD APR PY 1996 VL 1 IS 2 BP 5 EP 33 DI 10.2307/3985110 PG 29 WC Environmental Studies; History SC Environmental Sciences & Ecology; History GA WE837 UT WOS:A1996WE83700001 ER PT J AU King, RB Bhattacharyya, NK Wiemers, KD AF King, RB Bhattacharyya, NK Wiemers, KD TI Noble metal catalyzed hydrogen generation from formic acid in nitrite containing simulated nuclear waste media SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GLASS; MELTERS AB The Hanford Waste Vitrification Plant (HWVP) is being designed by the U.S. Department of Energy to immobilize high-level nuclear waste. Simulants for the HWVP feed containing the major nonradioactive components Al, Cd, Fe, Mn, Nd, Ni, Si, Zr, Na, CO32-, NO3-, and NO2- were used as media to evaluate the stability of formic acid toward hydrogen evolution by the reaction HCO2H --> H-2 + CO2 catalyzed by the noble metals Ru, Rh, and/or Pd found in significant quantities in uranium fission products. Small-scale experiments using 40-50 mt of feed simulant in closed glass reactors (250 - 550 m L total volume) at 80-100 degrees C were used to study the effect of nitrite and nitrate ion on the catalytic a ctivities of the noble metals for formic acid decomposition. Reactions were monitored using gas chromatography to analyze the CO2, H-2, NO, and N2O in the gas phase as a function of time. Rhodium, which was introduced as soluble RhCl3 . 3H(2)O, was found to be the most active catalyst for hydrogen generation from formic acid above similar to 80 degrees C in the presence of nitrite ion in accord with earlier observations. The apparent homogeneous nature of the nitrite-promoted Rh-catalyzed formic acid decomposition is consistent with the approximate pseudo-first-order dependence of the hydrogen production rate on Rh concentration. Titration of the typical feed simulants containing carbonate and nitrite with formic acid in the presence of rhodium at the reaction temperature (similar to 90 degrees C) indicates that the nitrite-promoted Rh-catalyzed decomposition of formic acid occurs only after formic acid has reacted with all of the carbonate and nitrite present to form CO2 and NO/N2O, respectively. The catalytic activities of Ru and Pd toward hydrogen generation from formic acid are quite different from those of Rh in that they a re inhibited rather than promoted by the presence of nitrite ion. Palladium is also an active catalyst for the reduction of nitrate to N2O by formic acid in feed simulant media. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP King, RB (reprint author), UNIV GEORGIA, DEPT CHEM, ATHENS, GA 30602 USA. NR 25 TC 12 Z9 12 U1 2 U2 29 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD APR PY 1996 VL 30 IS 4 BP 1292 EP 1299 DI 10.1021/es950524c PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA UC413 UT WOS:A1996UC41300054 ER PT J AU McKone, TE AF McKone, TE TI Overview of the risk analysis approach and terminology: The merging of science, judgment and values SO FOOD CONTROL LA English DT Article DE risk assessment; food contaminants; exposure; toxicity ID UNCERTAINTY AB Risk assessment is a process for identifying adverse consequences and their associated probability. As applied to impacts on human health from contaminant residuals in food, risk assessment involves four steps - (i) determination of exposure media (food) contaminant concentrations; (ii) exposure assessment; (iii) toxicity assessment; and (iv) risk characterization. The goal of this paper is to provide an overview of the risk assessment process and identify terminology and methods. In the area of public health protection, risk assessment has proven most useful when applied to endpoints with high negative value (or negative utility) such as disasters and irreversible diseases such as cancer and birth defects. Less success has been attained when it is applied to reversible and/or threshold-type diseases such as muscle dysfunction and neurological effects. We will consider why this is and what this implies for the application of risk assessment to a broader range of human diseases and low likelihood impacts. An important issue in health risk assessment is how precisely we cart characterize the distribution among individuals and/or species of potential effects and whether this level of precision favours one or another action. Copyright (C) 1996 Elsevier Science Ltd. C1 UNIV CALIF BERKELEY,SCH PUBL HLTH,BERKELEY,CA 94720. RP McKone, TE (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720, USA. NR 17 TC 12 Z9 12 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0956-7135 J9 FOOD CONTROL JI Food Control PD APR PY 1996 VL 7 IS 2 BP 69 EP 76 DI 10.1016/0956-7135(95)00047-X PG 8 WC Food Science & Technology SC Food Science & Technology GA UU703 UT WOS:A1996UU70300003 ER PT J AU Jenssen, TA Congdon, JD Fischer, RU Estes, R Kling, D Edmands, S Berna, H AF Jenssen, TA Congdon, JD Fischer, RU Estes, R Kling, D Edmands, S Berna, H TI Behavioural, thermal, and metabolic characteristics of a wintering lizard (Anolis carolinensis) from South Carolina SO FUNCTIONAL ECOLOGY LA English DT Article DE energetics; seasonality; social behaviour; thermal regulation; time-budget ID SEASONALITY; IGUANIDAE; TEMPERATURE; MORPHOLOGY; HABITAT; SAURIA AB 1. Anolis carolinensis, the most northerly distributed member of its neotropical genus, does not hibernate, but facultatively basks during days with direct sunlight throughout the December to March period. 2. Both sexes were primarily inactive (92% of emerged time), infrequently foraging (6.4%), interacting socially (1.3%), or responding to predator threats (<0.1%). 3. Because subjects infrequently moved (averaging 2 cmh(-1)), apparent thermoregulatory behaviour (i.e. sun/shade shuttling) was rarely observed. 4. Body (T-b) and concurrent air (T-a) temperature relationships for emerged lizards were: maximum TbS range of 33-34 degrees C, a mean T-b of 23 degrees C, and a mean T-b-T-a differential of 2.4 degrees C (ranging up to 15 degrees C). 5. Several criteria characterized winter A. carolinensis as being passive, thermal generalists. 6. Mean monthly oxygen uptake for wintering A. carolinensis was estimated at 0.924 December), 0.686 (January), 0.884 (February), and 1.118 (March) Ml g(-1) day(-1). 7. The total estimated energy expenditure for the four months by the average male (3.8g body mass) and female (2.9 g body mass) was 1.99 and 1.52 kcal, respectively, which is equivalent to 0.21 and 0.16 g of lipid metabolized, respectively (approximate to 6% of body mass). 8. Compared to metabolic rates at the species' 32-35 degrees C preferred T-b range, the 23 degrees C average T-b of emerged lizards represented a 60% reduction in energy expenditure. We speculate that the observed basking T(b)s reflect an adaptive trade-off between nonbasking TbS for minimum metabolic costs and optimally high TbS to facilitate physiological processes (e.g. gonadal recrudescence), but at a threat to lipid reserves. C1 SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NR 57 TC 31 Z9 31 U1 2 U2 14 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0269-8463 J9 FUNCT ECOL JI Funct. Ecol. PD APR PY 1996 VL 10 IS 2 BP 201 EP 209 DI 10.2307/2389844 PG 9 WC Ecology SC Environmental Sciences & Ecology GA UV192 UT WOS:A1996UV19200006 ER PT J AU Smith, DL Ikeda, Y Uno, Y AF Smith, DL Ikeda, Y Uno, Y TI An investigation into the possibility of performing radiography with gamma rays emitted from water made radioactive by irradiation with 14 MeV D-T fusion neutrons SO FUSION ENGINEERING AND DESIGN LA English DT Article AB Most conceptual designs for D-T fusion reactors incorporate water cooling. However, the water becomes temporarily radioactive, mainly from O-16(n,p)N-16 reactions induced by H-3(d,n)He-4 fusion neutrons. Reported studies of this phenomenon generally examine various related detrimental effects. The present investigation explores a potentially beneficial application of this radioactivity for radiography. This is accomplished using 6.129 and 7.115 MeV photons generated by the decay of 7.13 s N-16. Th, concept is demonstrated here by using D-T fusion neutrons from a neutron generator to activate water. A simple radiography apparatus was constructed by circulating pure water between the accelerator target region and a remote location where photon transmission measurements were conducted using a collimated photon source and detector arrangement. Four objects with distinct features were examined in this work. These measurements demonstrated that features like hidden holes and discontinuities in atomic number could be identified easily by observing variations in photon transmission. Spatial resolutions consistent with the geometry of this apparatus were observed in all instances. This paper also discusses advantages this technique might offer when applied in an actual D-T fusion reactor environment. C1 JAPAN ATOM ENERGY RES INST,DEPT REACTOR ENGN,FUS NEUTRON LAB,TOKAI,IBARAKI 31911,JAPAN. RP Smith, DL (reprint author), ARGONNE NATL LAB,TECHNOL DEV DIV,ARGONNE,IL 60439, USA. NR 15 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 0920-3796 J9 FUSION ENG DES JI Fusion Eng. Des. PD APR PY 1996 VL 31 IS 1 BP 41 EP 52 DI 10.1016/0920-3796(95)00420-3 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA UM268 UT WOS:A1996UM26800005 ER PT J AU Li, WH Ju, X Soloway, RD Wu, JG Ferraro, JR Shen, GR Xu, DF Xu, GX AF Li, WH Ju, X Soloway, RD Wu, JG Ferraro, JR Shen, GR Xu, DF Xu, GX TI Spectroscopic and X-ray conformation that copper coordinates with bilirubin oxygen as well as nitrogens in forming copper bilirubinate. SO GASTROENTEROLOGY LA English DT Meeting Abstract C1 BEIJING UNIV, DEPT CHEM, BEIJING 100871, PEOPLES R CHINA. ACAD SINICA, INST HIGH ENERGY PHYS, BEIJING, PEOPLES R CHINA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. UNIV TEXAS, MED BRANCH, DEPT INTERNAL MED, GALVESTON, TX 77550 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU W B SAUNDERS CO-ELSEVIER INC PI PHILADELPHIA PA 1600 JOHN F KENNEDY BOULEVARD, STE 1800, PHILADELPHIA, PA 19103-2899 USA SN 0016-5085 J9 GASTROENTEROLOGY JI Gastroenterology PD APR PY 1996 VL 110 IS 4 SU S BP A465 EP A465 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA UF737 UT WOS:A1996UF73701851 ER PT J AU Panjehpour, M Overholt, BF VoDinh, T Haggitt, RC Edwards, DH Buckley, FP Decosta, JF AF Panjehpour, M Overholt, BF VoDinh, T Haggitt, RC Edwards, DH Buckley, FP Decosta, JF TI Fluorescence spectroscopy for detection of dysplasia in Barrett's esophagus SO GASTROENTEROLOGY LA English DT Meeting Abstract C1 THOMPSON CANC SURVIVAL CTR, KNOXVILLE, TN USA. OAK RIDGE NATL LAB, OAK RIDGE, TN USA. UNIV WASHINGTON, MED CTR, SEATTLE, WA 98195 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU W B SAUNDERS CO-ELSEVIER INC PI PHILADELPHIA PA 1600 JOHN F KENNEDY BOULEVARD, STE 1800, PHILADELPHIA, PA 19103-2899 USA SN 0016-5085 J9 GASTROENTEROLOGY JI Gastroenterology PD APR PY 1996 VL 110 IS 4 SU S BP A574 EP A574 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA UF737 UT WOS:A1996UF73702285 ER PT J AU Taylor, K Hornigold, N Conway, D Williams, D Ulinowski, Z Agochiya, M Fattorini, P deJong, P Little, PFR Wolfe, J AF Taylor, K Hornigold, N Conway, D Williams, D Ulinowski, Z Agochiya, M Fattorini, P deJong, P Little, PFR Wolfe, J TI Mapping the human Y chromosome by fingerprinting cosmid clones SO GENOME RESEARCH LA English DT Article ID YEAST ARTIFICIAL CHROMOSOMES; ESCHERICHIA-COLI CHROMOSOME; HUMAN X-CHROMOSOME; PHYSICAL MAP; DELETION MAP; DNA CLONES; GENOME; GENE; SEQUENCES; REGION AB We have used Y-specific cosmid clones in a random fingerprinting approach to build contigs on the human Y chromosome. Clones derived from two libraries have been analyzed. The construction of one library is described here, the second was the Y chromosome-specific library LLOYNCO3 ''M'' (Lawrence Livermore National Laboratory). To date, we have fingerprinted 4430 cosmids: 377 contigs have been constructed containing from 2 to 39 clones. Along with the singletons, we estimate that we have covered 72.5% of the euchomatic portion of the Y chromosome with Fingerprinted clones. Sequence tagged sites are being used to anchor cosmids and contigs onto the YAC framework. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON SW7 2AZ,ENGLAND. RP Taylor, K (reprint author), UNIV LONDON UNIV COLL,GALTON LAB,LONDON NW1 2HE,ENGLAND. RI Little, Peter. F.R./C-9971-2009 NR 52 TC 26 Z9 26 U1 0 U2 0 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 SN 1054-9803 J9 GENOME RES JI Genome Res. PD APR PY 1996 VL 6 IS 4 BP 235 EP 248 DI 10.1101/gr.6.4.235 PG 14 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA UJ014 UT WOS:A1996UJ01400001 PM 8723717 ER PT J AU Shannon, M Ashworth, LK Mucenski, ML Lamerdin, JE Branscomb, E Stubbs, L AF Shannon, M Ashworth, LK Mucenski, ML Lamerdin, JE Branscomb, E Stubbs, L TI Comparative analysis of a conserved zinc finger gene cluster on human chromosome 19q and mouse chromosome 7 SO GENOMICS LA English DT Article ID PROTEINS; SUBFAMILY; FRAGMENTS; LINKAGE; CELLS AB Several lines of evidence now suggest that many of the zinc-finger-containing (ZNF) genes in the human genome are arranged in clusters. However, little is known about the structure or function of the clusters or about their conservation throughout evolution. Here, we report the analysis of a conserved ZNF gene cluster located in human chromosome 19q13.2 and mouse chromosome 7. Our results indicate that the human cluster consists of at least 10 related Kruppel-associated box (KRAB)-containing ZNF genes organized in tandem over a distance of 350-450 kb. Two cDNA clones representing genes in the murine cluster have been studied in detail. The KRAB A domains of these genes are nearly identical and are highly similar to human 19q13.2-derived KRAB sequences, but DNA-binding ZNF domains and other portions of the genes differ considerably. The two murine genes display distinct expression patterns, but are coexpressed in some adult tissues. These studies pave the way for a systematic analysis of the evolution of structure and function of genes within the numerous clustered ZNF families located on human chromosome 19 and elsewhere in the human and mouse genomes. (C) 1996 Academic Press, Inc. C1 OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN 37831. LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94551. OI Stubbs, Lisa/0000-0002-9556-1972 NR 32 TC 40 Z9 43 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0888-7543 J9 GENOMICS JI Genomics PD APR 1 PY 1996 VL 33 IS 1 BP 112 EP 120 DI 10.1006/geno.1996.0166 PG 9 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA UF102 UT WOS:A1996UF10200014 PM 8617494 ER PT J AU Lennon, G Auffray, C Polymeropoulos, M Soares, MB AF Lennon, G Auffray, C Polymeropoulos, M Soares, MB TI The IMAGE consortium: An integrated molecular analysis of genomes and their expression SO GENOMICS LA English DT Article ID HYBRIDIZATION C1 CNRS,F-94801 VILLEJUIF,FRANCE. GENEXPRESS,EVRY,FRANCE. NIH,NATL CTR HUMAN GENOME RES,BETHESDA,MD 20892. COLUMBIA UNIV,DEPT PSYCHIAT,NEW YORK,NY 10032. RP Lennon, G (reprint author), LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,L452,LIVERMORE,CA 94550, USA. NR 8 TC 1074 Z9 1081 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 0888-7543 J9 GENOMICS JI Genomics PD APR 1 PY 1996 VL 33 IS 1 BP 151 EP 152 DI 10.1006/geno.1996.0177 PG 2 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA UF102 UT WOS:A1996UF10200025 PM 8617505 ER PT J AU Glass, RJ Nicholl, MJ AF Glass, RJ Nicholl, MJ TI Physics of gravity fingering of immiscible fluids within porous media: An overview of current understanding and selected complicating factors SO GEODERMA LA English DT Article; Proceedings Paper CT Workshop on Fingered Flow in Unsaturated Soil - From Nature to Model CY APR 20, 1994 CL WAGENINGEN, NETHERLANDS ID WETTING FRONT INSTABILITY; STABILITY ANALYSIS; LAYERED SOILS; 2 DIMENSIONS; FLOW; INFILTRATION AB While gravity fingering of water in unsaturated sands has been demonstrated and studied under constrained laboratory conditions, its significance under field conditions in the vadose zone is still under debate. We review current understanding of the gravity fingering process as developed through linear stability analysis and laboratory experiments. With respect to many complicating factors inherent in the field, this understanding is deficient in determining the field conditions where gravity fingering can be expected and the behavior of the field-scale fingering process when it occurs. This deficiency is exemplified in the results we present of a field experiment conducted in a sandy alluvial deposit. While simple extrapolation of current understanding of the process predicted instability, fingers did not occur. To begin to understand the influence of complicating factors inherent in the field, we conducted several laboratory experiments that address three important complicating factors: uniform and non-uniform initial moisture content, media heterogeneity, and the presence of macropores and fractures. These factors can fundamentally alter the gravity fingering process, its scale of expression and, under many field conditions, suppress its occurrence entirely. While the significance of gravity fingering of water in a wettable vadose zone is still inconclusive, gravity fingering will likely play a significant role in water/NAPL (nonaqueous-phase liquid) or water/NAPL/air systems, as occur within the saturated and vadose zones, respectively, at many contaminated industrial sites. To demonstrate this role, the results of a simple experiment are presented. RP Glass, RJ (reprint author), SANDIA NATL LABS, DEPT GEOHYDROL 6115, POB 5800, ALBUQUERQUE, NM 87185 USA. NR 37 TC 92 Z9 95 U1 4 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0016-7061 J9 GEODERMA JI Geoderma PD APR PY 1996 VL 70 IS 2-4 BP 133 EP 163 DI 10.1016/0016-7061(95)00078-X PG 31 WC Soil Science SC Agriculture GA UR842 UT WOS:A1996UR84200005 ER PT J AU Glass, RJ Yarrington, L AF Glass, RJ Yarrington, L TI Simulation of gravity fingering in porous media using a modified invasion percolation model SO GEODERMA LA English DT Article; Proceedings Paper CT Workshop on Fingered Flow in Unsaturated Soil - From Nature to Model CY APR 20, 1994 CL WAGENINGEN, NETHERLANDS ID WETTING FRONT INSTABILITY AB We introduce a modified invasion percolation (MIP) model for the immiscible displacement of a nonwetting fluid by a wetting fluid within a porous network. The model includes the influence of gravity and is applicable in the quasi-static limit of infinitesimal flow rate where viscous forces are negligible with respect to gravity and capillary forces. The incorporation of gravity alone creates complicated, pore-scale gravity fingers. To properly model wetting fluid invasion where macroscopic gravity fingers form, we incorporate a pore-scale geometric capillary smoothing function we refer to as ''facilitation.'' Facilitation models the physics of wetting fluid invasion of pores by modifying the capillary pressure required to fill a pore based on the number of adjacent necks connecting the pore to the invading wetting fluid. The wetting fluid invasion facilitation process creates compact clusters and macroscopic fronts in horizontal simulations and in combination with gravity, creates macroscopic, gravity fingers that are in qualitative agreement with physical experiments. The MIP model yields much different imbibition front structures than standard invasion percolation. For MIP, capillary fingering, capillary facilitation, and gravity fingering compete to determine the wetted network structure as a function of pore-size distribution. RP Glass, RJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 15 TC 42 Z9 44 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0016-7061 J9 GEODERMA JI Geoderma PD APR PY 1996 VL 70 IS 2-4 BP 231 EP 252 DI 10.1016/0016-7061(95)00087-9 PG 22 WC Soil Science SC Agriculture GA UR842 UT WOS:A1996UR84200010 ER PT J AU Schmitz, B Asaro, F AF Schmitz, B Asaro, F TI Iridium geochemistry of volcanic ash layers from the early Eocene rifting of the northeastern North Atlantic and some other Phanerozoic events SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article ID CRETACEOUS-TERTIARY BOUNDARY; CHICXULUB CRATER; KILAUEA VOLCANO; TRACE-ELEMENTS; FLOOD BASALTS; K/T BOUNDARY; MAGMA SERIES; IR; IMPACT; BASIN AB This study shows that some types of explosive volcanism can result in significant Ir anomalies (up to 750 ppt); however, these are readily discerned from impact-related, extraterrestrial Ir anomalies by other chemical and mineralogical criteria, Iridium and major and trace elements were analyzed in 34 of the > 180 volcanic ash layers in the Fur Formation of early Eocene age in Denmark, These ashes originate from explosive volcanism during rifting of the Greenland Eurasia continent and subsequent sea-floor spreading in the young northeastern North Atlantic, In addition, 15 older Phanerozoic ashes, associated with other dramatic global events, have been analyzed for Ir. The Fur Formation ashes are unusually well preserved and have a wide compositional range-for example, rhyolitic, dacitic, tholeiitic and alkaline basaltic, mafic alkaline, and different salic alkaline ashes, and ashes with intermediate or unknown magma origin, The original magma compositions have been determined by immobile element plots (Nb/Y-Zr/Ti) and other criteria, Iridium shows a bimodal distribution, where all types of salic (alkaline as well as subalkaline) ashes have very low Ir concentrations (< 50 ppt), similar to values for average continental crust, whereas all types of basaltic ashes show higher concentrations, generally in the range 70-450 ppt, A strongly alkaline, mafic (nephelinitic) ash holds 102 +/- 29 ppt Ir, Another ash, with an unusual major-element composition and a composite acid-mafic mineral assemblage, contains 610 +/- 26 ppt Ir. Analyses of 15 of the >140 tholeiitic ash layers in the upper Fur Formation give very homogeneous major-element results, The Ir content, however, varies considerably, from 30 to 380 ppt with a mean of 181 ppt, Iridium does not correlate with any other analyzed elements, and no clues on its phase partitioning are revealed, Neither are there any temporal trends in Ir or any other element distributions indicative of any magma evolution. The older Phanerozoic volcanic ashes analyzed for Ir include: (1) the Upper Ordovician Big Bentonite, a 1- to 2-m-thick bentonite that may represent the largest Phanerozoic volcanic ash fall recorded; (2) volcanic ash layers near the Cretaceous-Tertiary boundary in continental deposits in Montana; (3) bentonites found in Sweden at the Llandovery-Wenlock boundary, where the largest conodont extinction event in the Silurian took place; and (4) two smectitic layers from Upper Cretaceous deposits in Germany, including the marker bed for the lower-upper Maastrichtian boundary, All these layers show very low Ir concentrations (<50 ppt) similar to average continental crust. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Schmitz, B (reprint author), UNIV GOTHENBURG,CTR EARTH SCI,CTR MARINE GEOL,S-41381 GOTHENBURG,SWEDEN. NR 97 TC 23 Z9 24 U1 1 U2 7 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD APR PY 1996 VL 108 IS 4 BP 489 EP 504 DI 10.1130/0016-7606(1996)108<0489:IGOVAL>2.3.CO;2 PG 16 WC Geosciences, Multidisciplinary SC Geology GA UE647 UT WOS:A1996UE64700007 ER PT J AU Ingram, BL Ingle, JC Conrad, ME AF Ingram, BL Ingle, JC Conrad, ME TI A 2000 yr record of Sacramento San Joaquin river inflow to San Francisco Bay estuary, California SO GEOLOGY LA English DT Article ID PALEOSALINITY; CLIMATE; LAKE AB Oxygen and carbon isotopic measurements of fossil bivalves (Macoma nasuta) contained in estuarine sediment are used to reconstruct a late Holocene record of salinity and stream flow in San Francisco Bay. Discharge into the bay is a particularly good indicator of paleoclimate in California because the bay's influent streams drain 40% of the state, The isotopic record suggests that between about 1670 and 1900 calendar years (yr cal) B.P. inflow to the bay was substantially greater than the estimated prediversion inflow of 1100 m(3)/s, An unconformity representing a 900 yr hiatus is present in the core between 1670 and 750 yr cal B.P., possibly caused by a major hydrological event. Over the past 750 yr, stream flow to San Francisco Bay has varied with a period of 200 yr; alternate wet and dry (drought) intervals typically have lasted 40 to 160 yr. C1 STANFORD UNIV,DEPT GEOL & ENVIRONM SCI,STANFORD,CA 94305. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY CTR ISOTOPE GEOCHEM,BERKELEY,CA 94720. RP Ingram, BL (reprint author), UNIV CALIF BERKELEY,DEPT GEOG,BERKELEY,CA 94720, USA. RI Conrad, Mark/G-2767-2010 NR 28 TC 59 Z9 59 U1 0 U2 6 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD APR PY 1996 VL 24 IS 4 BP 331 EP 334 DI 10.1130/0091-7613(1996)024<0331:AYROSS>2.3.CO;2 PG 4 WC Geology SC Geology GA UE646 UT WOS:A1996UE64600011 ER PT J AU Fliedner, MM Ruppert, S Malin, PE Park, SK Jiracek, G Phinney, RA Saleeby, JB Wernicke, B Clayton, R Keller, R Miller, K Jones, C Luetgert, JH Mooney, WD Oliver, H Klemperer, SL Thompson, GA AF Fliedner, MM Ruppert, S Malin, PE Park, SK Jiracek, G Phinney, RA Saleeby, JB Wernicke, B Clayton, R Keller, R Miller, K Jones, C Luetgert, JH Mooney, WD Oliver, H Klemperer, SL Thompson, GA TI Three-dimensional crustal structure of the southern Sierra Nevada from seismic fan profiles and gravity modeling SO GEOLOGY LA English DT Article ID CALIFORNIA; EXTENSION; UPLIFT; VALLEY AB Traveltime data from the 1993 Southern Sierra Nevada Continental Dynamics seismic refraction experiment reveal low crustal velocities in the southern Sierra Nevada and Basin and Range province of California (6.0 to 6.6 km/s), as well as low upper mantle velocities (7.6 to 7.8 km/s),The crust thickens from southeast to northwest along the axis of the Sierra Nevada from 27 km in the Mojave Desert to 43 km near Fresno, California. A crustal welt is present beneath the Sierra Nevada, but the deepest Moho is found under the western slopes, not beneath the highest topography. A density model directly derived from the crustal velocity model but with constant mantle density satisfies the pronounced negative Bouguer anomaly associated with the Sierra Nevada, but shows large discrepancies of >50 mgal in the Great Valley and in the Basin and Range province. Matching the observed gravity with anomalies in the crust alone is not possible with geologically reasonable densities; we require a contribution from the upper mantle, either by lateral density variations or by a thinning of the lithosphere under the Sierra Nevada and the Basin and Range province. Such a model is consistent with the interpretation that the uplift of the present Sierra Nevada is caused and dynamically supported by asthenospheric upwelling or litho spheric thinning under the Basin and Range province and eastern Sierra Nevada. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. DUKE UNIV,DURHAM,NC 27706. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. SAN DIEGO STATE UNIV,SAN DIEGO,CA 92182. PRINCETON UNIV,PRINCETON,NJ 08544. CALTECH,PASADENA,CA 91125. UNIV TEXAS,EL PASO,TX 79968. UNIV NEVADA,RENO,NV 89557. RP Fliedner, MM (reprint author), STANFORD UNIV,DEPT GEOPHYS,STANFORD,CA 94305, USA. RI Klemperer, Simon/A-5919-2012; Miller, Kate/E-6800-2012; OI Klemperer, Simon/0000-0001-7050-1829 NR 19 TC 71 Z9 71 U1 1 U2 7 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD APR PY 1996 VL 24 IS 4 BP 367 EP 370 DI 10.1130/0091-7613(1996)024<0367:TDCSOT>2.3.CO;2 PG 4 WC Geology SC Geology GA UE646 UT WOS:A1996UE64600020 ER PT J AU Gladney, ES Roelandts, I AF Gladney, ES Roelandts, I TI Distribution of CCRMP, NIST, and USGS reference material data in the literature (1950-1989) SO GEOSTANDARDS NEWSLETTER LA English DT Article ID ELEMENTAL CONCENTRATION DATA; 1988 COMPILATION; REFERENCE SAMPLES; GXR-1; SO-1; NBS AB Publication patterns of CCRMP, NIST, and USGS reference materials are traced over the past 40 years by literature source, analytical method employed, and constituents measured. This is the first update to our 1987 paper which covered the period 1951 - 1985. C1 UNIV LIEGE,B-4000 LIEGE 1,BELGIUM. RP Gladney, ES (reprint author), LOS ALAMOS NATL LAB,GRP ESH 17,MS J-978,LOS ALAMOS,NM 87545, USA. NR 31 TC 1 Z9 1 U1 0 U2 0 PU GEOSTANDARDS PI VANDOEUVRE NANCY PA 15 RUE NOTRE-DAME-DES-PAUVRES BP 20, 54501 VANDOEUVRE NANCY, FRANCE SN 0150-5505 J9 GEOSTANDARD NEWSLETT JI Geostand. Newsl. PD APR PY 1996 VL 20 IS 1 BP 45 EP 55 DI 10.1111/j.1751-908X.1996.tb00170.x PG 11 WC Geosciences, Multidisciplinary SC Geology GA UM217 UT WOS:A1996UM21700005 ER PT J AU Sturchio, NC Ohsawa, S Sano, Y Arehart, G Kitaoka, K Yusa, Y AF Sturchio, NC Ohsawa, S Sano, Y Arehart, G Kitaoka, K Yusa, Y TI Geochemical characteristics of the Yufuin outflow plume, Beppu hydrothermal system, Japan SO GEOTHERMICS LA English DT Article DE Beppu hydrothermal system; geochemistry; steam wells; thermal waters; stable isotopes; outflow plumes; Japan ID GASES AB Thermal water at Yufuin (Kyushu Island, Japan) is tapped through about 820 shallow wells and used mainly for hot-spring bathing purposes. Chemical and isotopic data for fluids from wells and fumaroles in Yufuin and Beppu indicate that the thermal activity at Yufuin represents a dilute, westward-flowing hydrothermal outflow plume from the Beppu hydrothermal system. Two other (eastward-flowing) outflow plumes have long been recognized at Beppu, but the Yufuin outflow plume is first recognized here, The Yufuin outflow plume is apparently a mixture of two end-member fluids: (1) deep high-temperature (250-300 degrees C) fluid from the Beppu system having high chloride concentration (1400-1600 mg/L) and a delta(18)O value near -6.0 parts per thousand, and (2) meteoric water having low chloride concentration (less than or equal to 7 mg/L) and a delta(18)O value near -9.2 parts per thousand. A permeable conduit for the vertical and lateral transport of deep fluid from the Beppu system is provided by the Yufuin Fault zone, which extends westward from the southern flank of Mt. Tsurumi volcano to the town of Yufuin. Stable isotope ratios and chloride concentrations for shallow groundwaters near the eastern end of the fault, at an elevation near 700 m, are consistent with those required for the low-chloride meteoric end-member of the Yufuin thermal waters. Recharge of this meteoric water, as well as mixing with the Beppu deep fluid, may occur along the Yufuin Fault. Enthalpy-chloride relations indicate additional conductive heating of the Yufuin waters, in the amount of 350-500 kJ/kg beyond that which can be accounted for by mixing between Beppu deep fluid and meteoric water. This could be a result of conductive heating with convection to a depth of 1-2 km. Estimates of the magnitude of the heat source for the Beppu hydrothermal system should take into account the heat being discharged at Yufuin. C1 KYOTO UNIV,BEPPU GEOPHYS RES LAB,BEPPU,OITA 874,JAPAN. HIROSHIMA UNIV,DEPT EARTH & PLANETARY SCI,HIGASHIHIROSHIMA 724,JAPAN. RP Sturchio, NC (reprint author), ARGONNE NATL LAB,GEOSCI CMT 205,ARGONNE,IL 60439, USA. NR 27 TC 11 Z9 11 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0375-6505 J9 GEOTHERMICS JI Geothermics PD APR PY 1996 VL 25 IS 2 BP 215 EP 230 DI 10.1016/0375-6505(95)00049-6 PG 16 WC Energy & Fuels; Geosciences, Multidisciplinary SC Energy & Fuels; Geology GA UF436 UT WOS:A1996UF43600003 ER PT J AU Howarth, RB Monahan, PA AF Howarth, RB Monahan, PA TI Economics, ethics, and climate policy: Framing the debate SO GLOBAL AND PLANETARY CHANGE LA English DT Article ID GREENHOUSE; EMISSIONS; COSTS AB This paper examines the economic and ethical dimensions of climate policy in light of existing knowledge of the impacts of global warming and the costs of greenhouse gas emissions abatement. We find that the criterion of economic efficiency, operationalized through cost-benefit analysis, is ill-equipped to cope with the pervasive uncertainties and issues of intergenerational fairness that characterize climate change. In contrast, the concept of sustainable development-that today's policies should ensure that future generations enjoy life opportunities undiminished relative to the present-is a normative criterion that explicitly addresses the uncertainties and distributional aspects of global environmental change. If one interprets the sustainability criterion to imply that it is morally wrong to impose catastrophic risks on unborn generations when reducing those risks would not noticeably diminish the quality of life of existing persons, a case can be made for significant steps to reduce greenhouse gas emissions. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720. RP Howarth, RB (reprint author), UNIV CALIF SANTA CRUZ,ENVIRONM STUDIES PROGRAM,SANTA CRUZ,CA 95064, USA. OI Howarth, Richard/0000-0003-3182-7345 NR 60 TC 13 Z9 13 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD APR PY 1996 VL 11 IS 4 BP 187 EP 199 DI 10.1016/0921-8181(95)00052-6 PG 13 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA UU702 UT WOS:A1996UU70200005 ER PT J AU George, AC AF George, AC TI State-of-the-art instruments for measuring radon thoron and their progeny in dwellings - A review SO HEALTH PHYSICS LA English DT Review DE radon; thoron; radon progeny; instrumentation ID INDOOR RADON; AIR; COLLECTOR; RN-222 AB Radon and radon progeny measurements are conducted world-wide for the assessment of the radiation dose to workers and the general public, In the last 10 years, a variety of instruments have been developed that utilize different principles of detection for different measurement applications, The various instruments and methods used today depend on whether radon or radon/thoron progeny are being measured, the type of radiation being detected, and also the duration of the measurement, Other important design criteria are applicability, portability, convenience, reliability, and cost considerations. The instruments under consideration use the following detection systems: pulse ionization chambers, electret ionization chambers, scintillation detectors with zinc sulfide ZnS(Ag), alpha particle spectrometers with silicon diodes, surface barrier or diffused junction detectors, registration of nuclear tracks in solid-state materials, and gamma-ray spectrometry with NaI(TI) scintillation crystals or germanium lithium (GeLi) semiconductors, Discussed in this paper are the advantages and disadvantages of the various portable instrumentation used for measuring radon, thoron, and their progeny. Also provided is guidance for their application in the field. RP George, AC (reprint author), US DOE, ENVIRONM MEASUREMENTS LAB, 376 HUDSON ST, NEW YORK, NY 10014 USA. NR 31 TC 55 Z9 58 U1 1 U2 13 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 APR PY 1996 VL 70 IS 4 BP 451 EP 463 DI 10.1097/00004032-199604000-00001 PG 13 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 UA703 UT WOS:A1996UA70300001 PM 8617584 ER PT J AU Espegren, ML Pierce, GA Halford, DK AF Espegren, ML Pierce, GA Halford, DK TI Comparison of risk for pre- and post-remediation of uranium mill tailings from vicinity properties in Monticello, Utah SO HEALTH PHYSICS LA English DT Article DE tailings, uranium; dose equivalent, effective; gamma radiation; radium ID PROTECTION; RADIATION AB Pre- and post-remedial action dose rates were calculated on 101 Monticello, Utah, properties included in the Monticello Vicinity Properly Remedial Action Project. Dose rates were calculated using the RESRAD computer code, which indicated that 98% of the effective dose equivalent was contributed by external gamma radiation and radon emanation. Radium concentrations in pCi g(-1) were averaged for pre-and post-remedial action measurements; point sources were not included in the averages. The volume of the deposit was also used in the dose calculation. In all cases the dose was reduced, and at 77 properties the dose was reduced to 0.30 mSv y(-1) (Department of Energy ALARA recommendation). A paired t-test showed a significant reduction (p < 0.05) between the pre- and post-remedial action dose rates. The average cost of remedial action, number of persons per household, number of properties remediated, and the reduction of cancer mortalities through remediation resulted in an approximate cost of $11,000,000 per life saved by remediation of mill tailings. RP Espegren, ML (reprint author), OAK RIDGE NATL LAB, POB 2567, GRAND JCT, CO 81502 USA. NR 13 TC 2 Z9 2 U1 1 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD APR PY 1996 VL 70 IS 4 BP 556 EP 558 DI 10.1097/00004032-199604000-00014 PG 3 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 UA703 UT WOS:A1996UA70300014 PM 8617597 ER PT J AU Ravigururajan, TS Rabas, TJ AF Ravigururajan, TS Rabas, TJ TI Turbulent flow in integrally enhanced tubes .1. Comprehensive review and database development SO HEAT TRANSFER ENGINEERING LA English DT Article ID HEAT-TRANSFER AB Thermal performance improvements through passive and active enhancement methods have been studied intensely for over three decades. Heat exchangers with single-phase tube-side flow are one of the important applications where passive surface-modification methods are popularly employed. Ribs, indentations, spiral-flutes, and coil inserts are some common surface modification techniques that are relatively easy to manufacture, are cost effective for many applications, and can be used conveniently for retubing existing heat exchangers. This article describes a comprehensive database that was developed to provide easy access to existing single-phase tube-side heat transfer and pressure drop data for different enhanced tube designs, in a consistent and useful manner. The database contains four files: (1) friction factor data, (2) heat transfer data, (3) tube characteristics, and (4) features of the experiments used by each data source, such as fluid type boundary conditions, tribe material and tube type. The friction factor database contains nearly 5,000 data points, and the heat transfer database contains more than 4,700 data points. The data encompass more than 360 different tube geometries from over 35 investigations. The information can be used by practicing engineers for validatating and/or developing prediction methods, or to compare or estimate the performance of a specific tube design. C1 ARGONNE NATL LAB,DIV ENERGY SYST,ARGONNE,IL 60439. RP Ravigururajan, TS (reprint author), WICHITA STATE UNIV,DEPT MECH ENGN,WICHITA,KS, USA. NR 40 TC 10 Z9 10 U1 0 U2 2 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD APR-JUN PY 1996 VL 17 IS 2 BP 19 EP 29 DI 10.1080/01457639608939870 PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA UX828 UT WOS:A1996UX82800002 ER PT J AU Ravigururajan, TS Rabas, TJ AF Ravigururajan, TS Rabas, TJ TI Turbulent flow in integrally enhanced tubes .2. Analysis and performance comparison SO HEAT TRANSFER ENGINEERING LA English DT Article ID HEAT-TRANSFER AB This article analyzes heat transfer and friction fractor data for single-phase turbulent flow inside enhanced tubes for different enhanced tube types and from different data soul ces. Data are given for several enhanced tube types such as extruded tubes (ribs ol disruptions with transverse and intermediate helix angles), spirally indented tubes, and tubes with coil inserts. In general, there is good agreement between the heat transfer data for tubes of the same type-manufactured with the same method-from different investigations with essentially the same disruption height, pitch, and helix angle. The variations increase (20-30%) when comparisons are mane with similar core geometries but different types such as indented and extruded, or indented and coil inserts. The performance of tubes with coil inserts is very similar to that of tubes with discrete extruded disruptions. There is substantially more deviation of the friction factor data from different sources, even for the same tube type. Also, the analysts shows that more care is required to obtain repeatable and high-quality friction factor data than heat transfer data. C1 ARGONNE NATL LAB,DIV ENERGY SYST,ARGONNE,IL 60439. RP Ravigururajan, TS (reprint author), WICHITA STATE UNIV,DEPT MECH ENGN,WICHITA,KS 67660, USA. NR 26 TC 4 Z9 4 U1 0 U2 0 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD APR-JUN PY 1996 VL 17 IS 2 BP 30 EP 40 DI 10.1080/01457639608939871 PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA UX828 UT WOS:A1996UX82800003 ER PT J AU Ballou, NE Ducatte, GR Quang, C Remcho, VT AF Ballou, NE Ducatte, GR Quang, C Remcho, VT TI Determination of chelating agents in hanford tank waste simulant by capillary zone electrophoresis SO HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY LA English DT Article DE chelating agents; complexation; capillary zone electrophoresis AB A capillary electrophoretic method has been developed which achieves rapid quantitative separation and determination of ethylenediaminetetraacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and nitrilotriacetic acid in Hanford tank waste simulant (TWS), Direct UV detection of Cu2+/chelator complexes is used to achieve enhanced sensitivity, The qualitative and quantitative reliability of the method and the quality of separations, as given by efficiency and resolution, is presented, In addition, the limits of detection and linearity of detector response with concentration are given for each chelator, The selection of Cu as the UV-absorbing species over other transition metals present in the waste is discussed. C1 W VIRGINIA UNIV, DEPT CHEM, MORGANTOWN, WV 26506 USA. PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU DR ALFRED HUTHIG VERLAG GMBH PI HEIDELBERG 1 PA POSTFACH 102869, W-69018 HEIDELBERG 1, GERMANY SN 0935-6304 J9 HRC-J HIGH RES CHROM JI HRC-J. High Resolut. Chromatogr. PD APR PY 1996 VL 19 IS 4 BP 183 EP 188 PG 6 WC Chemistry, Analytical SC Chemistry GA UM827 UT WOS:A1996UM82700001 ER PT J AU Durbin, PW Kullgren, B Jeung, N Xu, J Rodgers, SJ Raymond, KN AF Durbin, PW Kullgren, B Jeung, N Xu, J Rodgers, SJ Raymond, KN TI Octadentate catecholamide ligands for Pu(IV) based on linear or preorganized molecular backbones SO HUMAN & EXPERIMENTAL TOXICOLOGY LA English DT Article DE chelation therapy; octadentate catecholamide ligands; actinides ID ION SEQUESTERING AGENTS; CHELATION-THERAPY; DFO-HOPO; DTPA-DX; MICE; AMERICIUM; ACTINIDES; PLUTONIUM; REMOVAL; PU-238 AB Nine new octadentate ligands based on cyclic, spermine (3,4,3-LI), desferrioxamine (DFO), or H-shaped tetrakisamine (penten) molecular backbones were prepared containing catecholamide (CAM), carboxycatecholamide (CAM(C)), or terephthalamide (TAM) chelating units. Mice were injected intravenously with Pu-238(IV) citrate, treated with 30 mu mol kg(-1) of a ligand by intraperitoneal injection at 1 h or by gastric intubation at 3 min, and Pu retention in tissues and Pu transfer to excreta were measured at 24 h. Given by injection, three soluble ligands composed of MeTAM (3,4,3-LIMeTAM, DFO-MeTAM, H(2,2)-MeTAM) reduced Pu retention in the body to 27-28% of control compared with 32 and 37% of control obtained in mice similarly treated with 3,4,3-LICAM(C) or CaNa3-DTPA, respectively. The MeTAM ligands reduced Pu retention in the skeleton as much as an equimolar amount of CaNa3-DTPA, while Pu retention in the liver (on average, 16% of control) was significantly less than was obtained with CaNa3-DTPA (35% of control). Given orally, H(2,Z)-MeTAM reduced Pu retention in the whole body to 58% of control compared with reductions to 62 and 94% of control achieved with 3,4,3-LICAM(C) or CaNa3-DTPA, respectively. Penten is both partially preorganized for metal binding and spatially suitable for encapsulation of actinide(IV), and ligands with the penten backbone are easier and less costly to prepare than those based on spermine or DFO. The biological results confirmed that penten is a suitable as well as practical structural backbone for new octadentate ligands. In agreement with the great stability of the ferric complex with MeTAM, as determined in vitro, the small, simple, soluble penten-based octadentate ligand, H(2,2)-MeTAM, was shown to be, overall, the most effective catecholamide ligand for enhancing Pu excretion. Either combined in H(2,2)MeTAM or separately, the penten backbone and the MeTAM chelating unit are potentially useful additions to the set of backbones and binding units of multidentate ligands identified as effective for in vivo chelation of the actinides. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Durbin, PW (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. FU NIEHS NIH HHS [ES02698] NR 45 TC 16 Z9 17 U1 1 U2 1 PU STOCKTON PRESS PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE, HAMPSHIRE, ENGLAND RG21 6XS SN 0144-5952 J9 HUM EXP TOXICOL JI Hum. Exp. Toxicol. PD APR PY 1996 VL 15 IS 4 BP 352 EP 360 PG 9 WC Toxicology SC Toxicology GA UF147 UT WOS:A1996UF14700012 PM 8845226 ER PT J AU Tucker, JD Nath, J Hando, JC AF Tucker, JD Nath, J Hando, JC TI Activation status of the X chromosome in human micronucleated lymphocytes SO HUMAN GENETICS LA English DT Article ID CENTROMERE PROTEINS; Y-CHROMOSOME; INACTIVE-X; ANEUPLOIDY; METHYLATION; AGE AB The frequency of X chromosome aneuploidy in human female peripheral blood lymphocytes has been reported by several investigators to be significantly higher than expected based upon chance alone. Studies in our laboratory showed that 72% of the micronuclei in the peripheral blood of human females contained the X chromosome. Such a high frequency of X chromosome loss suggests that some unique mechanism may be responsible for this phenomenon. The present study was carried out to test the hypothesis that the lost or micronucleated chromsome is the inactive and not the active X. Blood samples were obtained from two unrelated females, 36 and 33 years of age, each with a different X; 9 reciprocal translocation. In each, the normal X chromosome is inactive and the translocated X is active. Isolated lymphocytes were cultured according to standard techniques and blocked with cytochalasin B. Using a modified micronucleus assay, we scored 10,000 binucleated cells from the 36 year old, while 9,500 binucleated cells were scored from the 33 year old. The slides were first labeled and the kinetochore status of each micronucleus was determined. This was followed by simultaneous hybridization with a 2.0 kilobase centromeric X chromosome-specific probe and a chromosome 9 specific whole chromosome painting probe. All micronucleated cells were relocated and scored for their probe status. A total of 217 micronuclei were scored from the two subjects, of which 96 (44.2%) contained the X chromosome. Of these 96 micronuclei, 80 (83.3%) contained the inactive X, based on the absence of chromosome 9 material in the micronucleus. These results support our hypothesis that the inactive X chromosome is preferentially included in the micronuclei, and suggest that the X chromosome hypoploidy observed at metaphase in aging women is a related phenomenon. C1 W VIRGINIA UNIV,COLL AGR & FORESTRY,GENET & DEV BIOL PROGRAM,MORGANTOWN,WV 26506. RP Tucker, JD (reprint author), LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,L-452,POB 808,LIVERMORE,CA 94551, USA. NR 22 TC 47 Z9 48 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 APR PY 1996 VL 97 IS 4 BP 471 EP 475 PG 5 WC Genetics & Heredity SC Genetics & Heredity GA TZ783 UT WOS:A1996TZ78300013 PM 8834245 ER PT J AU Smith, D Carrano, A AF Smith, D Carrano, A TI International large-scale sequencing meeting SO HUMAN GENOME NEWS LA English DT Article C1 US DOE,HLTH EFFECTS & LIFE SCI RES DIV,WASHINGTON,DC 20585. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 1 Z9 1 U1 0 U2 0 PU HUMAN GENOME MANAGE INF SYSTEM PI OAK RIDGE PA OAK RIDGE NATIONAL LABORATORY, 1060 COMMERCE PARK, OAK RIDGE, TN 37830 SN 1050-6101 J9 HUM GENOME NEWS JI Hum. Genome News PD APR-JUN PY 1996 VL 7 IS 6 BP 19 EP 19 PG 1 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA VB546 UT WOS:A1996VB54600012 ER PT J AU Deering, S Estrin, DL Farinacci, D Jacobson, V Liu, CG Wei, LM AF Deering, S Estrin, DL Farinacci, D Jacobson, V Liu, CG Wei, LM TI The PIM architecture for wide-area multicast routing SO IEEE-ACM TRANSACTIONS ON NETWORKING LA English DT Article ID STEINER AB The purpose of multicast routing is to reduce the communication costs for applications that send the same data to multiple recipients, Existing multicast routing mechanisms were intended for use within regions where a group is widely represented or bandwidth is universally plentiful, When group members, and senders to those group members, are distributed sparsely across a wide area, these schemes are not efficient; data packets or membership report information are occasionally sent over many links that do not lead to receivers or senders, respectively, We have developed a multicast routing architecture that efficiently establishes distribution trees across wide area internets, where many groups will be sparsely represented, Efficiency is measured in terms of the router state, control message processing, and data packet processing, required across the entire network in order to deliver data packets to the members of the group, Our protocol independent multicast (PIM) architecture: a) maintains the traditional IP multicast service model of receiver-initiated membership, b) supports both shared and source-specific (shortest-path) distribution trees, c) is not dependent on a specific unicast routing protocol, and d) uses soft-state mechanisms to adapt to underlying network conditions and group dynamics, The robustness, flexibility, and scaling properties of this architecture make it well-suited to large heterogeneous internetworks. C1 UNIV SO CALIF,DEPT COMP SCI,ISI,LOS ANGELES,CA 90089. CISCO SYST INC,SAN JOSE,CA 95134. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Deering, S (reprint author), XEROX CORP,PALO ALTO RES CTR,PALO ALTO,CA 94304, USA. NR 34 TC 207 Z9 220 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1063-6692 J9 IEEE ACM T NETWORK JI IEEE-ACM Trans. Netw. PD APR PY 1996 VL 4 IS 2 BP 153 EP 162 DI 10.1109/90.490743 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA UF639 UT WOS:A1996UF63900002 ER PT J AU Poggio, AJ Zacharias, RA Pennock, ST Avalle, CA Carney, H AF Poggio, AJ Zacharias, RA Pennock, ST Avalle, CA Carney, H TI NASA B-757 HIRF test series low power on-the-ground tests SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB The data acquisition phase of a program intended to provide data for the validation of computational, analytical and experimental techniques for the assessment of electromagnetic effects in commercial transports, for the checkout of instrumentation for following test programs, and for the support of protection engineering of airborne systems has been completed. Funded by the NASA Fly-By-Light/Power-By-Wire Program, the initial phase involved on-the-ground electromagnetic measurements using the NASA Boeing 757 and was executed in the LESLI Facility at the USAF Phillips Laboratory. The major participants were LLNL, NASA Langley Research Center, Phillips Laboratory, and UIE, Inc. Measurements were made of the fields coupled into the aircraft interior and signals induced in select structures and equipment under controlled illumination by RF fields. A characterization of the ground was also performed to permit ground effects to be included in forthcoming computer modeling exercises. A series of fly-by experiments were conducted in early 1995 in which the NASA B-757 was flown in the vicinity of a Voice of America station (similar to 25 MHz), a fixed transmitter driving a log periodic array (172 MHz), and an ASRF radar at Wallops Island (430 MHz). In this paper, the overall test program is defined with particular attention to the on-the-ground portion. The test rationale, test layout, and samples of the data are described. Samples of some inferences from the data that will be useful in protection engineering and EM effects mitigation will also be presented. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP Poggio, AJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD APR PY 1996 VL 11 IS 4 BP 27 EP 33 DI 10.1109/62.490221 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA UE972 UT WOS:A1996UE97200010 ER PT J AU Dodd, PE Lovejoy, ML Lundstrom, MS Melloch, MR Woodall, JM Pettit, D AF Dodd, PE Lovejoy, ML Lundstrom, MS Melloch, MR Woodall, JM Pettit, D TI Demonstration of npn InAs bipolar transistors with inverted base doping SO IEEE ELECTRON DEVICE LETTERS LA English DT Article ID GAIN AB We demonstrate np(+)n InAs bipolar transistors that operate under room temperature and cryogenic conditions. InAs transistors on an InP substrate were characterized as a function of temperature and exhibited good room temperature and low temperature common-emitter characteristics. Although the base doping density exceeded the emitter doping density by a factor of 20, current gains of 30 were achieved at room temperature, Junction leakage currents and contact resistance were identified as problems to address. C1 PURDUE UNIV,SCH ELECT & COMP ENGN,W LAFAYETTE,IN 47907. PURDUE UNIV,NSF,MRSEC TECHNOL ENABLING HETEROSTRUCT,W LAFAYETTE,IN 47907. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP Dodd, PE (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 13 TC 13 Z9 13 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD APR PY 1996 VL 17 IS 4 BP 166 EP 168 DI 10.1109/55.485162 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA UC510 UT WOS:A1996UC51000004 ER PT J AU Hadley, GR Lear, KL Warren, ME Choquette, KD Scott, JW Corzine, SW AF Hadley, GR Lear, KL Warren, ME Choquette, KD Scott, JW Corzine, SW TI Comprehensive numerical modeling of vertical-cavity surface-emitting lasers SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID GAIN; PERFORMANCE; DIODES AB We present a comprehensive numerical model for vertical-cavity surface-emitting lasers that includes all major processes affecting cw operation of axisymmetric devices. In particular, our model includes a description of the 2-D transport of electrons and holes through the cladding layers to the quantum well(s), diffusion and recombination of these carriers within the wells, the 2-D transport of heat throughout the device, and a multilateral-mode effective index optical model, The optical gain acquired by photons traversing the quantum wells is computed including the effects of strained band structure and quantum confinement, We employ our model to predict the behavior of higher-order lateral modes in proton-implanted devices and to provide an understanding of index-guiding in devices fabricated using selective oxidation. C1 OPT CONCEPTS INC,LOMPOC,CA 93436. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. RP Hadley, GR (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 27 TC 131 Z9 140 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1996 VL 32 IS 4 BP 607 EP 616 DI 10.1109/3.488833 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA UE484 UT WOS:A1996UE48400004 ER PT J AU Marshall, CD Smith, LK Beach, RJ Emanuel, MA Schaffers, KI Skidmore, J Payne, SA Chai, BHT AF Marshall, CD Smith, LK Beach, RJ Emanuel, MA Schaffers, KI Skidmore, J Payne, SA Chai, BHT TI Diode-pumped ytterbium-doped Sr-5(PO4)(3)F laser performance SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID FLUORIDE FIBER LASER; YB-YAG LASER; MU-M; OPERATION; EMISSION AB The performance of the first diode-pumped Yb3+-doped Sr-5(PO4)(3)F (Yb:S-FAP) solid-state laser is discussed. An InGaAs diode array has been fabricated that has suitable specifications for pumping a 3 x 3 x 38 mm Yb:S-FAP rod, The saturation fluence for diode pumping was deduced to be 5.5 J/cm(2) for the particular 2.8 kW peak power diode array utilized in our studies, This is 2,5x higher than the intrinsic 2.2 J/cm(2) saturation fluence as is attributed to the 6.5 nm bandwidth of our diode pump array, The small signal gain is consistent with the previously measured emission cross section of 6.0 x 10(-20) cm(2), obtained from a narrowband-laser pumped gain experiment, Up to 1.7 J/cm(3) of stored energy density was achieved in a 6 x 6 x 44 mm Yb:S-FAP amplifier rod, In a free running configuration, diode-pumped slope efficiencies up to 43% (laser output energy/absorbed pump energy) were observed with output energies up to similar to 0.5 J per 1 ms pulse, When the rod was mounted in a copper block for cooling, 13 W of average power was produced with power supply limited operation at 70 Hz with 500 mu s pulses. C1 UNIV CENT FLORIDA,CTR RES EDUC OPT & LASERS,ORLANDO,FL 32826. RP Marshall, CD (reprint author), UNIV CALIF,LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 28 TC 54 Z9 56 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1996 VL 32 IS 4 BP 650 EP 656 DI 10.1109/3.488839 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA UE484 UT WOS:A1996UE48400010 ER PT J AU Narayanaswamy, S Seshan, S Amir, E Brewer, E Brodersen, RW Burchard, F Burstein, A Chang, YC Fox, A Gilbert, JM Han, R Katz, RH Long, AC Messerschmitt, DG Rabaey, JM AF Narayanaswamy, S Seshan, S Amir, E Brewer, E Brodersen, RW Burchard, F Burstein, A Chang, YC Fox, A Gilbert, JM Han, R Katz, RH Long, AC Messerschmitt, DG Rabaey, JM TI Application and network support for InfoPad SO IEEE PERSONAL COMMUNICATIONS LA English DT Article C1 IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NETWORKING RES GRP,BERKELEY,CA 94720. UNIV CALIF BERKELEY,ELECT ENGN & COMP SCI FAC,BERKELEY,CA 94720. HEWLETT PACKARD CO LABS,PALO ALTO,CA. UNIV CALIF BERKELEY,INFOPAD & DAEDALUS PROJECTS,BERKELEY,CA 94720. NR 23 TC 16 Z9 16 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1070-9916 J9 IEEE PERS COMMUN JI IEEE Pers. Commun. PD APR PY 1996 VL 3 IS 2 BP 4 EP 17 DI 10.1109/98.490749 PG 14 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA UF693 UT WOS:A1996UF69300001 ER PT J AU Peterson, AF Wilton, DR Jorgenson, RE AF Peterson, AF Wilton, DR Jorgenson, RE TI Variational nature of Galerkin and non-Galerkin moment method solutions SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article AB The variational aspects of secondary calculations based on a method of moments (MoM) solution are investigated. These calculations exhibit a type of second-order accuracy, regardless of whether or not the operator being discretized is self-adjoint, and regardless of whether or not testing functions are identical to the basis functions (Galerkin's method). Numerical results support these conclusions and suggest that the advantage of Galerkin's method in actual calculations is grossly overstated. C1 UNIV HOUSTON,DEPT ELECT ENGN,HOUSTON,TX 77204. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Peterson, AF (reprint author), GEORGIA INST TECHNOL,SCH ELECT & COMP ENGN,ATLANTA,GA 30332, USA. OI Peterson, Andrew/0000-0003-2375-9047 NR 6 TC 31 Z9 31 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD APR PY 1996 VL 44 IS 4 BP 500 EP 503 DI 10.1109/8.489301 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA UD858 UT WOS:A1996UD85800009 ER PT J AU Buescher, KL Kumar, PR AF Buescher, KL Kumar, PR TI Learning by canonical smooth estimation .1. Simultaneous estimation SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article ID LIMIT-THEOREMS AB This paper examines the problem of learning from examples in a framework that is based on, but more general than, Valiant's probably approximately correct (PAC) model for learning, In our framework, the learner observes examples that consist of sample points drawn and labeled according to a fixed, unknown probability distribution, Based on this empirical data, the learner must select, from a set of candidate functions, a particular function or ''hypothesis'' that will accurately predict the labels of future sample points, The expected mismatch between a hypothesis' prediction and the label of a new sample point is called the hypothesis' ''generalization error.'' Following the pioneering work of Vapnik and Chervonernkis, others have attacked this sort of learning problem by finding hypotheses that minimize the relative frequency-based empirical error estimate, We generalize this approach by examining the ''simultaneous estimation'' problem: When does some procedure exist for estimating the generalization error of all of the candidate hypotheses, simultaneously, from the same labeled sample? We demonstrate how one can learn from such a simultaneous error estimate and propose a new class of estimators called ''smooth estimators'' that, in many cases of interest, contains the empirical estimator, We characterize the class of simultaneous estimation problems solvable by a smooth estimator and give a canonical form for the smooth simultaneous estimator. C1 UNIV ILLINOIS, DEPT ELECT & COMP ENGN, URBANA, IL 61801 USA. UNIV ILLINOIS, COORDINATED SCI LAB, URBANA, IL 61801 USA. RP Buescher, KL (reprint author), LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 44 TC 19 Z9 19 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9286 EI 1558-2523 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD APR PY 1996 VL 41 IS 4 BP 545 EP 556 DI 10.1109/9.489275 PG 12 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA UF703 UT WOS:A1996UF70300006 ER PT J AU Buescher, KL Kumar, PR AF Buescher, KL Kumar, PR TI Learning by canonical smooth estimation .2. Learning and choice of model complexity SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article ID CROSS-VALIDATION; REGRESSION; ERROR AB This paper analyzes the properties of a procedure for learning from examples. This ''canonical learner'' is based on a canonical error estimator developed in a companion paper. In learning problems one can observe data that consists of labeled sample points, and the goal is to find a model or ''hypothesis'' from a set of candidates that will accurately predict the labels of new sample points. The expected mismatch between a hypothesis' prediction and the actual label of a new sample point is called the hypothesis' ''generalization error.'' We compare the canonical learner with the traditional technique of finding hypotheses that minimize the relative frequency-based empirical error estimate, It is shown that for a broad class of learning problems, the set of cases for which such empirical error minimization works is a proper subset of the cases for which the canonical learner works, We derive bounds to show that the number of samples required by these two methods is comparable. We also address the issue of how to determine the appropriate complexity for the class of candidate hypotheses. Many existing techniques solve this problem at the expense of requiring the evaluation of an absolute, a priori measure of each hypothesis' complexity, The method we present does not, It is based on an extension of the canonical learner and uses a natural, relative measure of each model's complexity. We show that this method will learn for a variety of common parametric hypothesis classes. Also,for a broad class of learning problems, we show that this method works whenever a certain conventional method for choosing model complexity does. C1 UNIV ILLINOIS, COORDINATED SCI LAB, URBANA, IL 61081 USA. UNIV ILLINOIS, DEPT ELECT & COMP ENGN, URBANA, IL 61081 USA. RP Buescher, KL (reprint author), LOS ALAMOS NATL LAB, POB 1663, LOS ALAMOS, NM 87545 USA. NR 51 TC 17 Z9 17 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD APR PY 1996 VL 41 IS 4 BP 557 EP 569 DI 10.1109/9.489276 PG 13 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA UF703 UT WOS:A1996UF70300007 ER PT J AU Cao, M Talwar, S Kramer, KJ Sigmon, TW Saraswat, KC AF Cao, M Talwar, S Kramer, KJ Sigmon, TW Saraswat, KC TI A high-performance polysilicon thin-film transistor using XeCl excimer laser crystallization of pre-patterned amorphous Si films SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article ID SILICON FILMS; TFT AB A high-performance polysilicon thin-film transistor (TFT) fabricated using XeCl excimer laser crystallization of pre-patterned amorphous Si films is presented, The enhanced TFT performance over previous reported results is attributed to pre-patterning before laser crystallization leading to enhanced lateral grain growth, Device performance has been systematically investigated as a function of the laser energy density, the repetition rate, and the number of laser shots, Under the optimal laser energy density, poly-Si TFT's fabricated using a simple low- temperature (less than or equal to 600 degrees C) process have field-effect mobilities of 91 cm(2)/V . s (electrons) and 55 cm(2)/V . s (holes), and ON/OFF current ratios over 10(7) at V-DS = 10 V. The excellent overall TFT performance is achieved without substrate heating during laser crystallization and without hydrogenation, The results also show that poly-Si TFT performance is not sensitive to the laser repetition rate and the number of laser shots above 10. C1 ULTRATECH STEPPER, SAN JOSE, CA 95134 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. STANFORD UNIV, CTR INTEGRATED SYST, STANFORD, CA 94305 USA. RP HEWLETT PACKARD LABS, 3500 DEER CREEK RD, PALO ALTO, CA 94304 USA. NR 13 TC 26 Z9 27 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9383 EI 1557-9646 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD APR PY 1996 VL 43 IS 4 BP 561 EP 567 DI 10.1109/16.485538 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA UC511 UT WOS:A1996UC51100008 ER PT J AU Sobering, TJ Kay, RR AF Sobering, TJ Kay, RR TI The impact of multiplexing on the dynamic requirements of analog-to-digital converters SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB In data acquisition applications where the signals being digitized are produced in a time-division multiplexed system, the required dynamic performance of the analog-to-digital converter (ADC) is no longer bound by the conditions set forth in the Sampling Theorem, This results from the introduction of very high-frequency information by the multiplexing process which, while not necessarily containing information of interest, must be processed by the input circuitry of the ADC, In this situation, signal bandwidths and slew rates can greatly exceed those produced in a Nyquist limited system and can surpass the capability of the ADC, thus degrading overall system performance, This paper will examine two common multiplexing schemes and their impact on ADC dynamic requirements, First, we will examine a simple voltage multiplexing scheme typically found in state-of-health or data-logging applications and develop the necessary equations to show how the ADC dynamic requirements are affected, Then, the analysis will be extended to a multiplexed photodiode array readout to see how this application further challenges the dynamic performance of the ADC, Finally, the issues associated with developing dynamic test methodologies for assessing ADC performance in multiplexed systems will be discussed. RP Sobering, TJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 5 TC 9 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1996 VL 45 IS 2 BP 616 EP 620 DI 10.1109/19.492798 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA UJ897 UT WOS:A1996UJ89700052 ER PT J AU Fleetwood, DM Gaillard, R AF Fleetwood, DM Gaillard, R TI Special issue on single-event effects and the space radiation environment - Foreword SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Editorial Material C1 NUCLETUDES SA,LES ULIS,FRANCE. RP Fleetwood, DM (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD APR PY 1996 VL 43 IS 2 BP 342 EP 342 PN 1 PG 1 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA UJ077 UT WOS:A1996UJ07700002 ER PT J AU Dodd, PE AF Dodd, PE TI Device simulation of charge collection and single-event upset SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Review ID SOFT ERROR RATE; HEAVY-ION; NUMERICAL-SIMULATION; CURRENT TRANSIENTS; SEMICONDUCTOR-DEVICES; SEU CHARACTERIZATION; RADIAL-DISTRIBUTION; SILICON DEVICES; VLSI CIRCUITS; MEMORY CELLS AB In this paper we review the current status of device simulation of ionizing-radiation-induced charge collection and single-event upset (SEU), with an emphasis on significant results of recent years, We present an overview of device-modeling techniques applicable to the SEU problem and the unique challenges this task presents to the device modeler, We examine unloaded simulations of radiation-induced charge collection in simple p/n diodes, SEU in dynamic random access memories (DRAM's), and SEU in static random access memories (SRAM's). We conclude with a few thoughts on future issues likely to confront the SEU device modeler. RP SANDIA NATL LABS, POB 5800, ALBUQUERQUE, NM 87185 USA. NR 146 TC 97 Z9 104 U1 1 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 EI 1558-1578 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD APR PY 1996 VL 43 IS 2 BP 561 EP 575 DI 10.1109/23.490901 PN 1 PG 15 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA UJ077 UT WOS:A1996UJ07700020 ER PT J AU Sexton, FW AF Sexton, FW TI Microbeam studies of single-event effects SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article ID INDUCED CHARGE-COLLECTION; BEAM-INDUCED CHARGE; ION MICROPROBE SYSTEM; NUCLEAR MICROPROBE; CURRENT TRANSIENTS; GAAS-MESFETS; CMOS SRAMS; N-TYPE; UPSETS; SILICON AB The application of heavy-ion microbeam systems to the study of single-event effects is reviewed. Apertured microbeam systems have been used since the early 1980's to study charge collection. This has led to the development of the present models for the transport of charge following heavy-ion strikes in semiconductors. More recently, magnetically focused scanned microbeams have allowed direct imaging of charge collection regions with a technique called IBICC (ion-beam induced charge collection). Charge collection depth can be extracted from the pulse height spectrum from well-defined regions of the IC. When applied to single event upset, those regions sensitive to upset have been directly mapped with scanned microbeam systems. Damage effects due to total-ionizing dose and displacement damage are discussed. These techniques have removed uncertainty associated with broad-beam techniques, and improved our understanding of the mechanisms responsible for single-event effects in IC's. RP Sexton, FW (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 58 TC 36 Z9 36 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD APR PY 1996 VL 43 IS 2 BP 687 EP 695 DI 10.1109/23.490912 PN 1 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA UJ077 UT WOS:A1996UJ07700031 ER PT J AU Modena, A Najmudin, Z Dangor, AE Clayton, CE Marsh, KA Joshi, C Malka, V Darrow, CB Danson, C AF Modena, A Najmudin, Z Dangor, AE Clayton, CE Marsh, KA Joshi, C Malka, V Darrow, CB Danson, C TI Observation of Raman forward scattering and electron acceleration in the relativistic regime SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE ID LASER; PLASMAS; PULSE AB Raman forward scattering (RFS) is observed in the interaction of a high intensity (>10(18) W/cm(2)) short pulse (<1 ps) laser with an underdense plasma (n(e) similar to 10(19) cm(-3)). Electrons are trapped and accelerated up to 44 MeV by the high-amplitude plasma wave produced by RFS. The laser spectrum is strongly modulated by the interaction, showing sidebands at the plasma frequency. Furthermore, as the quiver velocity of the electrons in the high electric field of the laser beam becomes relativistic, various effects are observed which can be attributed to the variation of electron mass with laser intensity. C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. ECOLE POLYTECH,LULI,PALAISEAU,FRANCE. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. RP Modena, A (reprint author), UNIV LONDON IMPERIAL COLL SCI & TECHNOL,BLACKETT LAB,PRINCE CONSORT RD,LONDON SW7 2AZ,ENGLAND. RI Malka, Victor/F-5260-2010; OI Najmudin, Zulfikar/0000-0001-6323-4005 NR 26 TC 59 Z9 60 U1 1 U2 9 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 APR PY 1996 VL 24 IS 2 BP 289 EP 295 DI 10.1109/27.509992 PG 7 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000003 ER PT J AU Leemans, WP Siders, CW Esarey, E Andreev, NE Shvets, G Mori, WB AF Leemans, WP Siders, CW Esarey, E Andreev, NE Shvets, G Mori, WB TI Plasma guiding and Wakefield generation for second-generation experiments SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE ID INTENSE LASER-PULSES; ELECTROMAGNETIC-WAVES; ACCELERATION; FREQUENCY; DYNAMICS AB A design study has been carried out for a second-generation experiment on laser guiding and wakefield excitation in a channel. From simple scaling laws for the wakefield amplitude, dephasing length, the relativistic group velocity factor gamma(g), and energy gain with and without guiding, we find that the parameter regime for a compact single stage GeV accelerator favors laser systems producing short pulses (10 fs less than or equal to tau less than or equal to 100 fs), each containing an energy on the order of 100 mJ to a few J's. Taking the dephasing length as the maximum acceleration distance, plasma channels with lengths of 1-10 cm and densities of 10(17)-10(19) cm(-3) need to be produced; whereas the design study has been primarily concerned with diffraction and channel guiding, dephasing and depletion limits, and linear wakefield theory, aspects of the effect of the plasma wave on the evolution of the laser pulse are discussed. We find that transverse and longitudinal pulse distortions could indeed affect the generated plasma wave phase velocity and amplitude, and hence may limit the achievable energy gains over the one-dimensional (1-D) linear estimates. Some issues for experiments on prototype small accelerators (100 MeV-1 GeV, cm scale) are also discussed. C1 USN,RES LAB,BEAM PHYS BRANCH,WASHINGTON,DC 20375. UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. RUSSIAN ACAD SCI,HIGH ENERGY DENS RES CTR,MOSCOW 127412,RUSSIA. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. RP Leemans, WP (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,CTR BEAM PHYS,BERKELEY,CA 94720, USA. NR 54 TC 69 Z9 69 U1 4 U2 9 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 APR PY 1996 VL 24 IS 2 BP 331 EP 342 DI 10.1109/27.509997 PG 12 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000008 ER PT J AU Shvets, G Wurtele, JS Chiou, TC Katsouleas, TC AF Shvets, G Wurtele, JS Chiou, TC Katsouleas, TC TI Excitation of accelerating wakefields in inhomogeneous plasmas SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE ID LASER-PULSES; ELECTROMAGNETIC-WAVES; RAMAN-SCATTERING; TENUOUS PLASMAS; INSTABILITY; ELECTRON AB The excitation of the wakefields in an inhomogeneous plasma by a short laser pulse is investigated theoretically. A general equation for the wake excitation in transversely nonuniform plasma is derived. This equation is applied to the step-function density profile model of hollow channel laser wakefield accelerator [1], [2]. A more realistic model, in which the transition between the evacuated channel and the homogeneous surrounding plasma occurs over a finite radial extent, is then analyzed. It is shown that the excited channel mode can interact resonantly with the plasma electrons inside the channel wall, leading to secular growth of the electric field. This eventually results in wavebreaking and the dissipation of the accelerating mode. We introduce an effective quality factor Q for the hollow channel laser wakefield geometry. This resonance limits the number of electron bunches that can be accelerated in the wake of single laser pulse. C1 UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. UNIV CALIF LOS ANGELES, DEPT ELECT ENGN ELECTROPHYS, LOS ANGELES, CA 90024 USA. RP Shvets, G (reprint author), PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. RI wurtele, Jonathan/J-6278-2016 OI wurtele, Jonathan/0000-0001-8401-0297 NR 41 TC 38 Z9 38 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1996 VL 24 IS 2 BP 351 EP 362 DI 10.1109/27.509999 PG 12 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000010 ER PT J AU Decker, CD Mori, WB Tzeng, KC Katsouleas, TC AF Decker, CD Mori, WB Tzeng, KC Katsouleas, TC TI Modeling single-frequency laser-plasma acceleration using particle-in-cell simulations: The physics of beam breakup SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE ID ELECTROMAGNETIC-WAVES; UNDERDENSE PLASMA; RAMAN-SCATTERING; STIMULATED RAMAN; TENUOUS PLASMAS; PULSES; INSTABILITY AB We investigate electron acceleration from space-charge waves driven by single-frequency lasers using a fully explicit particle-in-cell (PIC) model. The two dimensional (2-D) simulations model similar to 100 fs pulses at densities near n = 4 x 10(19) cm(-3) for 1-mu m lasers. The pulses are found to break up due to a combination of longitudinal and transverse bunching of the laser intensity via Raman forward scattering type instabilities. The ponderomotive force of these intensity modulations generates large amplitude plasma waves. Large numbers of self-trapped electrons and multiple Raman forward scattering satellites are observed. The relevance of these simulations to experiments is discussed. C1 UNIV CALIF LOS ANGELES,DEPT ELECT ENGN,LOS ANGELES,CA 90095. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90095. UNIV SO CALIF,DEPT ELECT ENGN,LOS ANGELES,CA 90089. RP Decker, CD (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 60 TC 24 Z9 24 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1996 VL 24 IS 2 BP 379 EP 392 DI 10.1109/27.510002 PG 14 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000013 ER PT J AU Bulanov, SV Esirkepov, TJ Naumova, NM Pegoraro, F Pogorelsky, IV Pukhov, AM AF Bulanov, SV Esirkepov, TJ Naumova, NM Pegoraro, F Pogorelsky, IV Pukhov, AM TI Controlled wake field acceleration via laser pulse shaping SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE ID HIGH-ENERGY; PLASMA; ELECTRONS; WAVES AB We consider the interaction of high-intensity laser pulses with underdense plasmas and address the problem of the excitation of strong and stable wake plasma waves with regular electric fields to provide effective acceleration of charged particles over appreciably long distances. It is known that a relativistically strong laser pulse longer than the wavelength of plasma waves, propagating in a plasma is subject to self-modulation. This may result in a nonstationary behavior of the produced plasma wake field/particle dephasing, and reduced net acceleration. In this paper we present the results of 1(2/2)-D and 2(1/2)-D particle in cell (PIC) simulations which demonstrate that regular wake electric fields may be obtained by a properly shaped laser pulse (sharp steepening of its leading front). These results are relevant to the design of the 100 MeV laser wake field electron acceleration experiment that uses a terawatt picosecond CO2 laser and is under construction at the Brookhaven Accelerator Test Facility. C1 CNR,INST PLASMA PHYS,I-20133 MILAN,ITALY. UNIV TURIN,DEPT THEORET PHYS,TURIN,ITALY. BROOKHAVEN NATL LAB,UPTON,NY 11973. MOSCOW INST PHYS & TECHNOL,DOLGOPRUDNYI,RUSSIA. RP Bulanov, SV (reprint author), RUSSIAN ACAD SCI,INST GEN PHYS,38 VAVILOV ST,MOSCOW,RUSSIA. RI Bulanov, Sergei/A-1721-2013; pukhov, alexander/C-8082-2016; OI Pegoraro, Francesco/0000-0002-7216-5491 NR 28 TC 41 Z9 41 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1996 VL 24 IS 2 BP 393 EP 399 DI 10.1109/27.510003 PG 7 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000014 ER PT J AU Bowers, RL Greene, AE Peterson, DL Roderick, NF Bartsch, RR Cochrane, JC Kruse, H AF Bowers, RL Greene, AE Peterson, DL Roderick, NF Bartsch, RR Cochrane, JC Kruse, H TI Initiation and assembly of the plasma in a plasma flow switch SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on 2nd-Generation Plasma Accelerators CY JUN 26-30, 1995 CL KARDAMYLI, GREECE AB A series of fast opening switch experiments was carried out on the Pegasus pulsed power facility. The first series of experiments characterized the assembly and run down of a 50 mg plasma how switch operating in the 6 MA regime. The switch plasma arises from the vaporization of a wire array and a barrier foil, Arrays with different numbers of wires were examined. Two-dimensional (2-D) radiation magnetohydrodynamic simulations of the initial vaporization stage of the array plasma and its assembly on the barrier foil are presented, which include the effects of initial perturbations on the evolution of the switch plasma as it moves down a coaxial gun barrel. Sparse wire arrays were observed to perform poorly. A change in the experimental design, motivated by 2-D simulations, led to improved performance. Computational results which lead to these changes are discussed, and the results are compared with experimental data. C1 UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. LOS ALAMOS NATL LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP Bowers, RL (reprint author), LOS ALAMOS NATL LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545, USA. NR 10 TC 6 Z9 6 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 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD APR PY 1996 VL 24 IS 2 BP 510 EP 522 DI 10.1109/27.510017 PG 13 WC Physics, Fluids & Plasmas SC Physics GA UP870 UT WOS:A1996UP87000028 ER PT J AU Byers, CH AF Byers, CH TI Professor C. Judson King III. An informal minibiography SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Item About an Individual RP Byers, CH (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 991 EP 992 DI 10.1021/ie960823q PG 2 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500001 ER PT J AU Byers, CH Williams, DF AF Byers, CH Williams, DF TI Efficient recovery of lanthanides by continuous ion exchange SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article AB Continuous annular sorption is a recent innovation that uses a slowly rotating annular sorbent bed to continuously separate components as a function of angular position. The current application of this technology, continuous ion exchange (CIEx), utilizes eluent in a much more efficient manner than the previous chromatographic applications. The efficient recovery of semidilute levels (10-20 mM) of lanthanide mixtures by CIEx is demonstrated experimentally, and a mathematical model of the process is used to predict equipment performance. Results from batch shake tests and fixed-bed runs support the CIEx modeling effort and are useful separative benchmarks. The implications of the results for scaleup and economic evaluation are examined. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. NR 19 TC 3 Z9 3 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 993 EP 998 DI 10.1021/ie9503205 PG 6 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500002 ER PT J AU Fenouil, LA Lynn, S AF Fenouil, LA Lynn, S TI Design of entrained-flow and moving-, packed-, and fluidized-bed sorption systems: Grain-model kinetics for hot coal-gas desulfurization with limestone SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID CALCIUM-OXIDE; SOLID REACTIONS; PORE MODEL; PARTICLES; CALCINATION; REACTORS AB Concentration profiles in several configurations of sorption systems (moving, packed, and fluidized beds and entrained-flow) were determined using the grain and the unreacted shrinking core model for the description of the gas-solid reaction kinetics. General equations for the design and analysis of all these reactor configurations are given, and simple analytical solutions are proposed. The behavior of these reactors can be expressed as a function of only four parameters: the size of the sorbent pellet and the Peclet, Sherwood (or Blot), and Damkohler numbers. These general equations were then applied to the lime(stone)/H2S systems. Using limestone particles with diameters on the order of 100 mu m for entrained-flow and with diameters on the order of 1 mm for the other configurations, it was found that H2S could be removed from the hot coal gas to near its equilibrium value with more than 75% sorbent utilization and with reasonable bed depth (about 1 m, or 1-s contact time for entrained-flow) when the reactor temperature is maintained 25-50 degrees C above the calcination temperature of the calcium carbonate. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 31 TC 21 Z9 21 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1024 EP 1043 DI 10.1021/ie950245y PG 20 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500006 ER PT J AU Broekhuis, RR Lynn, S King, CJ AF Broekhuis, RR Lynn, S King, CJ TI Recovery of propylene glycol from dilute aqueous solutions by complexation with organoboronates in ion-pair extractants SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article AB Recovery of propylene glycol (1,2-PD) from aqueous solution was studied in batch experiments using extractants consisting of ion pairs of Aliquat 336 and phenylboronate in 2-ethylhexanol, toluene, o-xylene, or diisobutyl ketone. The heterogeneous complexation constant beta(11) calculated from the results at 25 degrees C was highest in 2-ethylhexanol (49-100 (mol/L)(-1)). The equilibrium water concentration in the extractants was 8-12 wt % and decreased with increasing uptake of 1,2-PD. Nearly all extractant/diluent systems exhibited stoichiometric overloading. Evidence for aggregation of the ion-pair extractant in the organic phase was found from water solubilization studies and H-1 NMR spectroscopy studies. The complexation constant decreased with increasing temperature. Up to 80% of the extracted 1,2-PD was backextracted into water after acidification with CO2. The extractant could then be regenerated by stripping CO2 from solution at temperatures exceeding 110 degrees C. However, at these temperatures the color of the extractant changes, and the extraction capacity is reduced to about 60% of its original value. Regeneration by contacting with aqueous solutions of Na2CO3 did not cause extractant degradation; regeneration effectiveness increased with increasing pH. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 7 TC 10 Z9 12 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1206 EP 1214 DI 10.1021/ie950508o PG 9 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500026 ER PT J AU Dai, YY King, CJ AF Dai, YY King, CJ TI Selectivity between lactic acid and glucose during recovery of lactic acid with basic extractants and polymeric sorbents SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID AQUEOUS-SOLUTIONS; CARBOXYLIC-ACIDS; FERMENTATION BROTH; TERTIARY; AMINE; PH AB During recovery of product carboxylic acids from fermentation broths, it is important to maximize the selectivity for the desired acid, as opposed to substrate sugars. In this work uptakes of glucose and competitive uptakes of lactic acid and glucose have been measured for the extractant Alamine 336 in various diluents and three commercially available basic solid polymeric sorbents. The results show that swelling is the main factor governing the selectivity between lactic acid and glucose for the polymeric sorbents. Because of a high uptake capacity and relatively low swelling, Dowex MWA-1 gives a higher selectivity in the pH 5-6 range than do Amberlite IRA-35 and Reillex 425. Extraction with Alamine 336 provides a much higher selectivity, but a lower capacity, than the polymeric sorbents. The extent of water coextraction depends strongly on the diluent used, and larger amounts of water coextracted correspond to larger uptakes of glucose. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. NR 34 TC 14 Z9 20 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1215 EP 1224 DI 10.1021/ie9506274 PG 10 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500027 ER PT J AU Gupta, RB Prausnitz, JM AF Gupta, RB Prausnitz, JM TI Vapor-liquid equilibria for solvent-polymer systems from a perturbed hard-sphere-chain equation of state SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID FLUIDS; THERMODYNAMICS; SEPARATION; PHASE; AIR AB Vapor-liquid equilibria (VLE) for solvent-polymer mixtures at modest pressures are obtained from a perturbed hard-sphere-chain equation of state. This equation of state is the sum of a hard-sphere-chain term as the reference system and a van der Waals attractive term as the perturbation. The reference equation follows from the Percus-Yevick integral theory coupled with chain connectivity as described by Chiew. The effect of specific interactions, such as hydrogen bonding, is introduced through the proposal of Veytsman based on the statistical distribution of hydrogen bonds between donor and acceptor sites suggested by molecular structure. Calculated and observed vapor-liquid equilibria are presented for nonpolar, polar, and hydrogen-bonding solvent + homopolymer systems. Pure-component parameters (number of segments per molecule, segment-segment energy, and segment diameter) are obtained from pure-component properties: liquid density and vapor pressure data for normal fluids and pressure-volume-temperature data for polymers. A binary energy interaction parameter must be obtained from limited VLE data for each binary system; this parameter appears to be independent of temperature and composition over a useful range. Theoretical correlations and predictions are in good agreement with experiment. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 32 TC 18 Z9 18 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1225 EP 1230 DI 10.1021/ie950544n PG 6 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500028 ER PT J AU Shamsi, A AF Shamsi, A TI Catalytic and thermal cracking of coal-derived liquid in a fixed-bed reactor SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID CALCIUM-OXIDE; PYROLYSIS AB A coal-derived liquid, obtained from the Coal Technology Corp.'s mild gasification process, was cracked over char produced from Pittsburgh No. 8 coal mixed with Plum Run dolomite in the Foster Wheeler carbonizer. For the purpose of comparison, calcined Plum Run dolomite (PRD) char produced from Pittsburgh No. 8 coal, and silicon carbide (an inert material) were also studied. Coal liquid feed was analyzed by sulfur-selective gas chromatography (GC), liquid chromatography (LC), and proton nuclear magnetic resonance (NMR) and for elemental composition. The gaseous products of cracking were analyzed for hydrocarbons using GC. Most sulfur in the feed was present in molecules heavier than dibenzothiophene and was distributed in a variety of structures. The surviving coal liquid was analyzed by LC. The results indicated that deoxygenation of phenols, dealkylation of aromatic compounds (AR), and condensation of aromatic structures are some of the reactions occurring on the surface of bed materials. Energies of activation for homogeneous and for heterogeneous pyrolysis of the coal liquid were calculated after separating the rate of thermal cracking from the sum of rates of thermal and catalytic cracking. RP Shamsi, A (reprint author), US DOE,MORGANTOWN ENERGY TECHNOL CTR,POB 880,3610 COLLINS FERRY RD,MORGANTOWN,WV 26507, USA. NR 18 TC 7 Z9 7 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1251 EP 1256 DI 10.1021/ie9504765 PG 6 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500032 ER PT J AU Appelman, EH Jache, AW Muntean, JV AF Appelman, EH Jache, AW Muntean, JV TI Use of ozone plus hydrogen peroxide to degrade macroscopic quantities of chelating agents in an aqueous solution SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID ADVANCED OXIDATION PROCESSES; ULTRAVIOLET-RADIATION; WATER; DECOMPOSITION; STABILITY; COMPLEXES AB Ozone in the presence of hydrogen peroxide has been employed succesfully for the oxidative degradation of polycarboxylic and diphosphonic acid chelating agents present at the 0.1 M level in a neutral or weakly alkaline aqueous solution. The geminal diphosphonic acid complexants methanediphosphonic acid and (1-hydroxyethylidene)bisphosphonic acid have been successfully mineralized, as have the polycarboxylic acids ethylenediaminetetraacetic acid and tetrahydrofurantetracarboxylic acid. RP Appelman, EH (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 9 Z9 9 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD APR PY 1996 VL 35 IS 4 BP 1480 EP 1482 DI 10.1021/ie950367q PG 3 WC Engineering, Chemical SC Engineering GA UF015 UT WOS:A1996UF01500060 ER PT J AU Kaden, DA Warren, J Ryan, L Boorman, G Mellick, P AF Kaden, DA Warren, J Ryan, L Boorman, G Mellick, P TI The NTP/HEI collaborative ozone project on the health effects of chronic ozone inhalation SO INHALATION TOXICOLOGY LA English DT Article ID COLLAGEN-METABOLISM; AMBIENT LEVELS; LUNG COLLAGEN; ADULT-RATS; PPM OZONE; EXPOSURE; BRONCHIOLITIS; CONSEQUENCES; EPITHELIUM; RESPONSES AB Although many people are exposed to ozone, the effects of chronic exposure to this ubiquitous pollutant, especially low-level chronic exposure, are not well understood. The U.S. Environmental Protection Agency (EPA) current national ambient air quality standard for ozone is exceeded in many communities, especially during the summer. The standard is attained when the number of days per calendar year with maximum hourly average concentrations above 0.12 ppm is equal to or less than 1. The U.S. EPA estimates that 67 million people in the United States, or slightly more than a quarter of the residents, live in areas that were out of compliance with the current National Ambient Air Quality Standard (NAAQS) for ozone in 1989. Although there have been some studies of long-term exposure to ozone, many important questions remain about the health effects of chronic ozone exposure. The Health Effects Institute (HEI), in conjunction with the National Toxicology Program (NTP) carcinogenesis studies, has completed a major effort to help answer these questions. NTP included additional animals in its study for HEI investigators. Included in this effort is a set of studies examining histopathological, biochemical, morphological, and functional alterations in rats exposed to 0, 0.12, 0.5 or 1.0 ppm ozone for 20 mo. This article describes several aspects of this effort. This project can serve as a model for other large toxicological studies for which cancer may not be the only endpoint of concern. The additional animals required for the NTP/HEI Collaborative Ozone Project only represented a modest incremental cost, yet provided information on a much broader range of potential effects of ozone than the basic NTP carcinogenesis studies. C1 HARVARD UNIV, SCH PUBL HLTH, DANA FARBER CANC INST, BOSTON, MA 02115 USA. NIEHS, RES TRIANGLE PK, NC 27709 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Kaden, DA (reprint author), HLTH EFFECTS INST, 141 PORTLAND ST, SUITE 7300, CAMBRIDGE, MA 02139 USA. RI Ryan, Louise/A-4562-2009 OI Ryan, Louise/0000-0001-5957-2490 NR 47 TC 1 Z9 1 U1 0 U2 0 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0895-8378 J9 INHAL TOXICOL JI Inhal. Toxicol. PD APR PY 1996 VL 8 IS 3 BP 213 EP 227 DI 10.3109/08958379609005431 PG 15 WC Toxicology SC Toxicology GA UJ171 UT WOS:A1996UJ17100001 ER PT J AU Thrall, KD Kenny, DV AF Thrall, KD Kenny, DV TI Evaluation of a carbon tetrachloride physiologically based pharmacokinetic model using real-time breath-analysis monitoring of the rat SO INHALATION TOXICOLOGY LA English DT Article ID SEQUENTIAL MASS-SPECTROMETRY; VOLATILE ORGANIC-COMPOUNDS; TRIPLE QUADRUPOLES; CONSTANTS AB A methodology has been developed to monitor the exhalation of volatile compounds in rats in a real-time manner. The exhalation data is collected using an innovative breath-analysis system that links the exhaled breath from the rat directly with a mass spectrometer. Because the breath-analysis system generates a new data point approximately every second, this methodology can aid in describing the rapid exponential emptying of the blood compartment that occurs immediately following peak exposure. Furthermore, coupling the real-time collection of biokinetic data with a physiologically descriptive toxicokinetic model should be useful in elucidating complex in situ chemical-mediated biological reactions, particularly for rapidly occurring processes. The utility of this new methodology is illustrated using carbon tetrachloride (CCl4) as a demonstration compound. An existing physiologically based pharmacokinetic (PBPK) model was taken from the literature and modified to simulate an intravenous route of CCl4 exposure in the male Fischer 344 rat. This PBPK model for the rat accurately described the concentrations of CCl4 in real-time exhaled breath data collected from rats exposed to CCl4 via a single intravenous injection. C1 BATTELLE MEM INST, ATMOSPHER SCI & APPL TECHNOL, COLUMBUS, OH 43201 USA. RP Thrall, KD (reprint author), PACIFIC NW LAB, HLTH PROTECT DEPT, POB 999, MS K3-62, RICHLAND, WA 99352 USA. NR 11 TC 12 Z9 13 U1 0 U2 0 PU TAYLOR & FRANCIS PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 SN 0895-8378 J9 INHAL TOXICOL JI Inhal. Toxicol. PD APR PY 1996 VL 8 IS 3 BP 251 EP 261 DI 10.3109/08958379609005433 PG 11 WC Toxicology SC Toxicology GA UJ171 UT WOS:A1996UJ17100003 ER PT J AU Sozen, M Kuzay, TM AF Sozen, M Kuzay, TM TI Enhanced heat transfer in round tubes with porous inserts SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article DE porous media; fibrous; heat transfer AB The modeling and numerical simulation studies of fluid flow and enhanced heat transfer in round tubes filled with rolled copper mesh are described in this paper. The tubes were subjected to uniform heat flux, and water was used as the energy transport fluid. The numerical solution was obtained by a finite difference code developed in this investigation. The fluid flow was modeled by a modified Ergun-Forchheimer-Brinkman equation. The energy transfer was based on a single equation model; i.e., local thermal equilibrium between the solid and fluid phases. Variations of the local Nusselt number and local heat transfer coefficient were obtained accurately by the use of nonuniform grid size in the radial direction in the numerical simulations. The numerical results obtained were compared with the experimental results obtained by the Experimental Facilities Division at Argonne National Laboratory, and the two were in good agreement. C1 ARGONNE NATL LAB,ADV PHOTON SOURCE,EXPTL FACIL DIV,ARGONNE,IL 60439. RP Sozen, M (reprint author), SOUTHERN UNIV,DEPT MECH ENGN,BATON ROUGE,LA 70813, USA. NR 16 TC 23 Z9 26 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN PI WOBURN PA 225 WILDWOOD AVE #UNITB PO BOX 4500, WOBURN, MA 01801-2084 SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD APR PY 1996 VL 17 IS 2 BP 124 EP 129 DI 10.1016/0142-727X(95)00095-8 PG 6 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA UL243 UT WOS:A1996UL24300005 ER PT J AU Zaworski, JR Welty, JR Drost, MK AF Zaworski, JR Welty, JR Drost, MK TI Measurement and use of bi-directional reflectance SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article AB Bi-directional reflectance is a fundamental surface property that has received a great deal of attention, particularly during the early years of the space program. Although the value of using accurate surface property data has always been recognized, bi-directional reflectance information is rarely used because of the sheer volume of data involved. Now, with powerful workstations readily available, large Monte Carlo codes can be run very quickly and full advantage can be taken of the detailed surface property description provided by bi-directional reflectance data. This paper provides a detailed description of a simple, compact, flexible apparatus for measuring bi-directional reflectance and a review of measurement considerations. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Zaworski, JR (reprint author), OREGON STATE UNIV, DEPT MECH ENGN, CORVALLIS, OR 97331 USA. NR 14 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD APR PY 1996 VL 39 IS 6 BP 1149 EP 1156 DI 10.1016/0017-9310(95)00212-X PG 8 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA TT715 UT WOS:A1996TT71500004 ER PT J AU McEligot, DM Taylor, MF AF McEligot, DM Taylor, MF TI The turbulent Prandtl number in the near-wall region for low-Prandtl-number gas mixtures SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID CHANNEL FLOW; SIMULATION AB Results of experiments for binary gas mixtures, with molecular Prandtl numbers in the range 0.18-0.7 in flow in a smooth circular tube with constant transport properties were employed to examine models hypothesized for the distribution of the turbulent Prandtl number, Pr-t{y(+), Pr, Re}. These models included approximations of predictions from recent direct numerical simulations of turbulent duct flows. Data for a range of molecular Prandtl numbers for 'high' Reynolds numbers, similar to 3 x 10(4) < Re < similar to 1 x 10(5), were obtained earlier by the authors by utilizing mixtures formed by helium or hydrogen with xenon, argon or carbon dioxide. For the range 0.21 < Pr < 0.72, Reynolds analogy and the variable Pr-t{y(+), Pr, Re} model by Kays agreed with downstream measurements to within about 5%. C1 UNIV ARIZONA,TUCSON,AZ 85721. RP McEligot, DM (reprint author), LIT CO,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 49 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 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD APR PY 1996 VL 39 IS 6 BP 1287 EP 1295 DI 10.1016/0017-9310(95)00146-8 PG 9 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA TT715 UT WOS:A1996TT71500018 ER PT J AU Holland, WS Ade, PAR Griffin, MJ Hepburn, ID Vickers, DG Cunningham, CR Hastings, PR Gear, WK Duncan, WD Baillie, TEC Haller, EE Beeman, JW AF Holland, WS Ade, PAR Griffin, MJ Hepburn, ID Vickers, DG Cunningham, CR Hastings, PR Gear, WK Duncan, WD Baillie, TEC Haller, EE Beeman, JW TI 100 mK bolometers for the submillimetre common-user bolometer array (SCUBA) .1. Design and construction SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article AB We describe the design and construction of bolometric detectors for SCUBA - the Submillimetre Common-User Bolometer Array for the James Clerk Maxwell Telescope in Hawaii. The Instrument contains 131 individual detectors, in two arrays, optimized for the submillimetre atmospheric transmission windows. The detectors are cooled by dilution refrigeration to a temperature of 100 mK, so that the receiver performance will be limited by photon noise from the sky and telescope background in all wavebands. A future paper will describe the performance of the detectors with reference to typical data obtained during the laboratory commissioning period. C1 UNIV LONDON QUEEN MARY & WESTFIELD COLL,DEPT PHYS,LONDON E1 4NS,ENGLAND. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,BERKELEY,CA 94720. ROYAL OBSERV,EDINBURGH EH9 3HJ,MIDLOTHIAN,SCOTLAND. NR 28 TC 10 Z9 10 U1 1 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD APR PY 1996 VL 17 IS 4 BP 669 EP 692 DI 10.1007/BF02088363 PG 24 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA UE036 UT WOS:A1996UE03600001 ER PT J AU Rickert, M Wagner, P AF Rickert, M Wagner, P TI Parallel real-time implementation of large-scale, route-plan-driven traffic simulation SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C-PHYSICS AND COMPUTERS LA English DT Article DE traffic; cellular automata; complex systems; parallel computing AB This work is part of our ongoing effort to design and implement a traffic simulation application capable of handling realistic problem sizes in multiple real-time. Our traffic simulation model includes multi-lane vehicular traffic and individual route-plans. On a 16-CPU SGI Power Challenger and a 12-CPU SUN workstation-cluster we have reached real-time for the whole German Autobahn network. C1 LOS ALAMOS NATL LAB,TSA,DO,SA,LOS ALAMOS,NM 87545. RP Rickert, M (reprint author), UNIV COLOGNE,CTR PARALLEL COMP,D-50923 COLOGNE,GERMANY. NR 14 TC 25 Z9 25 U1 1 U2 3 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C-Phys. Comput. PD APR PY 1996 VL 7 IS 2 BP 133 EP 153 DI 10.1142/S0129183196000156 PG 21 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA VA937 UT WOS:A1996VA93700004 ER PT J AU Andrews, MJ ORourke, PJ AF Andrews, MJ ORourke, PJ TI The multiphase particle-in-cell (MP-PIC) method for dense particulate flows SO INTERNATIONAL JOURNAL OF MULTIPHASE FLOW LA English DT Article DE MP-PIC; sedimentation; separation; fluidized beds; CFD; one-dimensional; comprehensive multiphase flow AB A multiphase particle-in-cell (MP-PIC) method has been developed. This numerical technique draws upon the best of Eulerian/Eulerian continuum models and Eulerian/Lagrangian discrete models. The MP-PIC method uses an accurate mapping from Lagrangian particles to and from a computational grid. While on the grid, continuum derivative terms that treat the particle phase as a fluid are readily evaluated and then mapped back to individual particles. The result of this procedure is a computational technique for multiphase Rows that can handle particulate loading ranging from dense to dilute, a distribution of particle sizes and a range of particle materials. The dense particulate model represents separated flows of particles and includes drag exerted by a gas phase, inter-particle stresses, particle viscous stresses and gas pressure gradients. Six problems are presented to demonstrate the MP-PIC method. This MP-PIC method has important applications in fluidized beds (combustion, catalytic cracking), sedimentation, separation and many other granular flows. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Andrews, MJ (reprint author), TEXAS A&M UNIV,DEPT MECH ENGN,COLLEGE STN,TX 77843, USA. NR 24 TC 160 Z9 174 U1 4 U2 45 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0301-9322 J9 INT J MULTIPHAS FLOW JI Int. J. Multiph. Flow PD APR PY 1996 VL 22 IS 2 BP 379 EP 402 DI 10.1016/0301-9322(95)00072-0 PG 24 WC Mechanics SC Mechanics GA UC323 UT WOS:A1996UC32300012 ER PT J AU Yim, P Chun, JH Ando, T Sikka, VK AF Yim, P Chun, JH Ando, T Sikka, VK TI Production and characterization of mono sized Sn-Pb alloy balls SO INTERNATIONAL JOURNAL OF POWDER METALLURGY LA English DT Article ID DROPLETS; POWDERS AB Mono-sized balls of the eutectic Sn-38w/o Pb alloy were produced by controlling the break-up of a continuous laminar jet into uniform droplets and by rapidly solidifying the droplets in a silicone oil bath. Though other sizes are possible, the process parameters were selected to produce droplets of a fixed diameter between 700 and 800 mu m. The use of silicone oil assured fast cooling and minimum droplet merging. The balls showed high sphericity; narrow size distribution (within +/- 5% of the target diameter), and a uniform, rapidly solidified microstructure. They also showed uniform re-melting characteristics due to their homogeneous microstructures. The present study suggests that the mono-sized Sn-Pb alloy balls, produced by the Uniform-Droplet Spray (UDS) process, may be applicable to the manufacture of ball grid array (EGA) type multimodule integrated-circuit (IC) packaging. C1 TUFTS UNIV,DEPT MECH ENGN,MEDFORD,MA 02155. MARTIN MARIETTA ENERGY SYST INC,OAK RIDGE NATL LAB,MAT PROC,OAK RIDGE,TN 37831. RP Yim, P (reprint author), MIT,DEPT MECH ENGN,CAMBRIDGE,MA 02139, USA. NR 29 TC 21 Z9 25 U1 0 U2 7 PU AMER POWDER METALLURGY INST PI PRINCETON PA 105 COLLEGE ROAD EAST, PRINCETON, NJ 08540 SN 0888-7462 J9 INT J POWDER METALL JI Int. J. Powder Metall. PD APR PY 1996 VL 32 IS 2 BP 155 EP & PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA UF019 UT WOS:A1996UF01900007 ER PT J AU Chen, AM Lucas, JN Hill, FS Brenner, DJ Sachs, RK AF Chen, AM Lucas, JN Hill, FS Brenner, DJ Sachs, RK TI Proximity effects for chromosome aberrations measured by FISH SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID IN-SITU HYBRIDIZATION; HUMAN-LYMPHOCYTES; IONIZING-RADIATION; DNA DAMAGE; TRANSLOCATIONS; DICENTRICS; INDUCTION AB A Monte Carlo simulation computer program for radiation-produced chromosome aberrations, based on the breakage-and-reunion model, was extended to include proximity effects due to locailization of chromosomes and limited range for break-break interactions. Two adjustable parameters were used. One corresponds to total dose; the other determines proximity effects by specifying the number of 'interaction regions' in a cell nucleus. The use of additional adjustable parameters was avoided by assuming randomness of break induction and aberration production. FISH chromosome painting data were obtained from 1.9 Gy Co-60 gamma-rays-irradiated human lymphocytes. The data were compared with the computer simulation results, taking individual chromosome lengths into account. With about 13 interaction regions, agreement between the experiment and the simulation was good, even when detailed categories of damage were scored. An estimated average dsb-dsb interaction distance, based on 13 interaction regions, is about 1.3 mu m. Monte Carlo methods gave useful quantitative estimates of relative aberration yields, with a minimum of adjustable parameters and theoretical assumptions, and indicated proximity effects. Computer simulation of FISH experiments can be adapted to any number of colours, any scoring criteria and any method of grouping aberrations into categories. Simulation allows systematic extrapolation of aberration data on painted chromosomes to whole-genome aberration frequencies. C1 UNIV CALIF BERKELEY,DEPT MATH,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94551. COLUMBIA UNIV,CTR RADIOL RES,NEW YORK,NY 10032. FU NCI NIH HHS [CA12536] NR 66 TC 26 Z9 26 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD APR PY 1996 VL 69 IS 4 BP 411 EP 420 DI 10.1080/095530096145706 PG 10 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA UK063 UT WOS:A1996UK06300001 PM 8627123 ER PT J AU Bartkowiak, M Mahan, GD Modine, FA Alim, MA AF Bartkowiak, M Mahan, GD Modine, FA Alim, MA TI Multiple-peaked structure in the nonlinearity coefficient of ZnO varistors SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE varistors; I-V; nonlinearity; granular microstructure; junction networks; Voronoi network; simulations ID ZINC-OXIDE VARISTORS; GRAIN-SIZE AB Computer simulations of the current conduction through the granular microstructure of polycrystalline ZnO varistors are used to explain the multiple-peaked structure observed in the nonlinearity coefficient measured as a function of voltage for low-voltage varistors and for varistors with microelectrode contacts on their surface. Two-dimensional Voronoi networks with random mixtures of electrically nonlinear and ohmic elements are used to model the varistors. It is shown that the statistical dispersion of the grain sizes has no significant effect on the nonlinearity coefficient. The multiple-peaked structure is caused by a small amount of randomly distributed grain boundaries with ohmic behavior; i.e., linear current-voltage characteristics of low resistivity. The observed reduction of the maximum nonlinearity coefficient of polycrystalline varistors, relative to that of isolated grain boundaries, is attributed to the presence of varistor microjunctions with poor nonlinearity. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. HUBBELL INC,OHIO BRASS CO,WADSWORTH,OH 44281. RP Bartkowiak, M (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 17 TC 9 Z9 9 U1 0 U2 1 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD APR 1 PY 1996 VL 35 IS 4A BP L414 EP L417 DI 10.1143/JJAP.35.L414 PG 4 WC Physics, Applied SC Physics GA UF789 UT WOS:A1996UF78900002 ER PT J AU Simmons, JW Kemp, WE Dunning, JS AF Simmons, JW Kemp, WE Dunning, JS TI The P/M processing of high-nitrogen stainless steels SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article AB The production of high-nitrogen steels requires the utilization of unique melting and casting technologies such as pressurized electroslag remelting; however, production can be accomplished via powder metallurgy techniques utilizing lower-cost modifications to existing gas-atomization equipment and, in the solid state, by the development of novel processing schemes and equipment. This article describes two methods, one liquid- and one solid-state processing,for file production of high-nitrogen stainless steels - pressurized gas atomization and solid-state nitriding in a mechanical-fluidized vacuum machine. RP Simmons, JW (reprint author), US DOE,ALBANY RES CTR,1450 QUEEN AVE SW,ALBANY,OR 97321, USA. NR 7 TC 8 Z9 14 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 APR PY 1996 VL 48 IS 4 BP 20 EP 23 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA UF031 UT WOS:A1996UF03100013 ER PT J AU Wolfenden, A Cantu, MW Vaidya, RU AF Wolfenden, A Cantu, MW Vaidya, RU TI Experimental investigation of the dynamic elastic modulus and vibration damping in molybdenum and alumina-coated Ti-25Al-IONb-3V-IMo aluminides cycled at elevated temperatures SO JOURNAL OF ADVANCED MATERIALS LA English DT Article AB Titanium aluminides such as Ti-25Al-10Nb-3V-1Mo have become the focus of high temperature materials research due to their ability to maintain their strength up to 1,000 degrees C. However, at temperatures in excess of 650 degrees C, Ti-25Al-10Nb-3V-1Mo undergoes severe oxidation which, in turn, can degrade its mechanical properties. To address this problem, plasma sprayed coatings were applied to the substrate to provide protection in the high temperature environment. In this study 0.1-0.125 mm thick alumina and molybdenum coatings were plasma sprayed onto a Ti-25Al-10Nb-3V-1Mo substrate. Changes in dynamic elastic modulus and vibration damping due to thermal cycling at elevated temperatures were measured. The modulus and damping were measured using the piezoelectric ultrasonic composite oscillator technique (PUCOT), The behavior of the Al2O3 and Mo coated specimens was compared to that of the uncoated samples. Thermal cycling of the coated samples at 600 degrees C led to an increase in the modulus and decrease in the damping. Most of the changes in properties occurred after the first thermal cycle. Thermal cycling of the samples at 750 degrees C and 850 degrees C led to complete failure of the coatings. A specimen with a 1.0 mm alumina coating exhibited cracks even when cycled at 600 degrees C. C1 LOS ALAMOS NATL LAB,DIV MAT,LOS ALAMOS,NM. RP Wolfenden, A (reprint author), TEXAS A&M UNIV,DEPT MECH ENGN,ADV MAT LAB,COLLEGE STN,TX 77843, USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD APR PY 1996 VL 27 IS 3 BP 14 EP 21 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA UP064 UT WOS:A1996UP06400003 ER PT J AU Schwartz, SE AF Schwartz, SE TI The Whitehouse effect - Shortwave radiative forcing of climate by anthropogenic aerosols: An overview SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID ACID DEPOSITION; TROPOSPHERIC AEROSOLS; OPTICAL-PROPERTIES; ATLANTIC-OCEAN; SULFUR CYCLE; MODEL; SULFATE; BUDGET; TEMPERATURE; TRENDS AB Loadings of tropospheric aerosols have increased substantially over the past 150 yr as a consequence of industrial activities. These aerosols enhance reflection of solar radiation by the Earth-atmosphere system both directly, by scattering light in clear air and, indirectly, by increasing the reflectivity of clouds. The magnitude of the resultant decrease in absorption of solar radiation is estimated to be comparable on global average to the enhancement in infrared forcing at the tropopause due to increases in concentrations of CO2 and other greenhouse gases over the same time period. Estimates of the aerosol shortwave forcing are quite uncertain, by more than a factor of two about the current best estimates. This article reviews the atmospheric chemistry and microphysical processes that govern the loading and light scattering properties of the aerosol particles responsible for the direct effect and delineates the basis for the present estimates of the magnitude and uncertainty in the resultant radiative forcing. The principal sources of uncertainty are in the loading of anthropogenic aerosols, which is highly variable spatially and temporally because of the relatively short residence time of these aerosols (ca. 1 week) and the episodic removal in precipitation, and in the dependence of light scattering on particle size, and in turn on relative humidity. Uncertainty in aerosol forcing is the greatest source of uncertainty in radiative forcing of climate over the industrial period. At the high end of the uncertainty range, the aerosol forcing is comparable to the anthropogenic greenhouse forcing, and substantially greater in industrialized regions. Even at the low end of the range, the aerosol forcing cannot be neglected in considerations of influences on climate over the industrial period. This uncertainty greatly limits the ability to draw empirical inferences of climate sensitivity to radiative forcing. Copyright (C) 1996 Elsevier Science Ltd RP Schwartz, SE (reprint author), BROOKHAVEN NATL LAB, ENVIRONM CHEM DIV, UPTON, NY 11973 USA. RI Schwartz, Stephen/C-2729-2008 OI Schwartz, Stephen/0000-0001-6288-310X NR 93 TC 175 Z9 185 U1 4 U2 27 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD APR PY 1996 VL 27 IS 3 BP 359 EP 382 DI 10.1016/0021-8502(95)00533-1 PG 24 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UN409 UT WOS:A1996UN40900002 ER PT J AU Luan, S Pang, HM Houk, RS AF Luan, S Pang, HM Houk, RS TI Optical emission studies of the Mach disc extracted from an inductively coupled plasma with an echelle spectrometer and segmented-array charge-coupled detectors SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article DE inductively coupled plasma; supersonic jet; Mach disc; atomic emission spectrometry; simultaneous multi-element analysis ID MASS-SPECTROMETRY; ICP-OES; GAS AB An inductively coupled plasma (ICP) is extracted into a small quartz vacuum chamber through a sampling orifice in a water-cooled copper plate. Optical emission from the Mach disc region is measured with a new type of echelle spectrometer equipped with two segmented-array charge-coupled device detectors, the Optima 3000 from Perkin-Elmer. This device provides high quantum efficiency throughout the ultraviolet-visible region, as well as low dark current and readout noise, The spectral background emitted by the Mach disc is very low. Axial profiles of the optical emission of a range of atom and ion lines are measured. The effects of aerosol gas Bow rate on the intensities of various lines are investigated. The relationship between the location of the Mach disc and the pressure in the expansion chamber is also studied. The analyte line intensities are enhanced at higher pressure. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,USDA,DEPT CHEM,AMES,IA 50011. NR 20 TC 5 Z9 5 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 APR PY 1996 VL 11 IS 4 BP 247 EP 252 DI 10.1039/ja9961100247 PG 6 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA UF871 UT WOS:A1996UF87100002 ER PT J AU Eiden, GC Barinaga, CJ Koppenaal, DW AF Eiden, GC Barinaga, CJ Koppenaal, DW TI Selective removal of plasma matrix ions in plasma source mass spectrometry SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article DE ICP-MS; ion trap; space charge; ion-molecule reaction; hydrogen reaction ID INTERFERENCES AB We report a new method for selective removal of argon ions and other plasma matrix ions in plasma source MS. The method consists of sampling the plasma and reacting the sampled plasma and analyte ions with hydrogen gas. Reactions have been studied in three instruments: in the ion trap of a plasma source ion trap (PSIT) mass spectrometer and in the post-skimmer region of both a conventional ICP mass spectrometer and a second PSIT. In the ion trap, the reaction between Ar+ and H-2 proceeds at nearly the collisional rate whereas reaction of most other atomic ions is four to five orders of magnitude slower. For modest H-2 pressures and reaction times in the ion trap [10(-4) Torr (1 Torr = 133.322 Pa) and 10 ms], the Ar+ signal is reduced by six orders of magnitude. We have examined reactions of H-2 with 33 different atomic ions; the only ions for which a reaction was evident were N+, O+, Cl+, and Ar+. The decrease in Ar+ occurs by a sequence of fast reactions resulting in charge transfer from Ar+ to form the low m/z ions H-2(+) and H-3(+), which are rapidly ejected from the ion trap. The net effect is the selective removal of Ar+ chemically, not by virtue of its mass-to-charge ratio only, as in resonant ion ejection methods. In the conventional ICP-MS experiments the reaction time is short, limiting the decrease in Ar+ to about 40-fold in preliminary and unoptimized experiments. However, the reaction is still selective: simple scattering by H-2 reduces the Sc-45(+) signal at only 5% of the rate of reactive loss of Ar+. Production of H-2(+) and H-3(+) is observed directly in the conventional ICP-MS experiments, indicating that the chemistry in the post-skimmer region is consistent with that observed in the ion trap. We discuss methods by which the magnitude of Ar+ reduction observed in the ion trap might be realized in conventional ICP-MS, thus possibly allowing a greater analyte ion transmission efficiency and reduced space-charge effects. C1 PACIFIC NW NATL LAB,RICHLAND,WA 99352. NR 22 TC 90 Z9 92 U1 1 U2 7 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 APR PY 1996 VL 11 IS 4 BP 317 EP 322 DI 10.1039/ja9961100317 PG 6 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA UF871 UT WOS:A1996UF87100013 ER PT J AU Doran, JC AF Doran, JC TI The influence of canyon winds on flow fields near Colorado's Front Range SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DRAINAGE FLOWS; VALLEY AB A network of sodars was operated in the late summer and fall of 1993 to monitor the occurrence of nocturnal winds from a canyon in Colorado's Front Range near the Rocky Flats Plant and to determine the influence of those winds on the Bow fields over the plant. The canyon Bows could be broadly classified into two categories: well developed and irregular. The well-developed flows were generally stronger, deeper, and more continuous than the irregular ones, and the canyon's influence on the wind fields near the plant site was confined primarily to periods with these flows. These periods, in turn, usually followed days during which a deep mixed layer formed over the plains to the east of the mountains. Following days with shallower mixed layers, the canyon winds tended to be weaker and shallower. Numerical simulations with a nested mesoscale numerical model were used to examine the mechanisms responsible for this behavior. The nighttime simulated temperature gradients between the air near the mountain slopes and the free air over the plains were found to be larger after days with deep mixed layers, resulting in stronger down-canyon flows at night. In addition, for the deeper mixed-layer cases, air parcels descending the slope do so in more neutrally stratified conditions so that their buoyant acceleration down the slope is maintained. A notable exception to this behavior occurred on one night when nonstationary waves appeared to disrupt the canyon flows. Marker particles released into the simulated flow fields were used to follow the motion of air parcels from the mountains out over the plains. They revealed a tendency for air parcels to remain elevated when they exit the valley on nights with lighter canyon winds and shallower afternoon mixed layers, thereby reducing the canyon's potential effect on the near-surface winds over the Rocky Flats Plant. Particle trajectories were also used to examine the concept of a well-defined airshed feeding a draining valley; the concept was found to be of limited validity for the topography in this area. RP Doran, JC (reprint author), PACIFIC NW LAB, EARTH & ENVIRONM SCI CTR, POB 999, MS K9-30, RICHLAND, WA 99352 USA. NR 23 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD APR PY 1996 VL 35 IS 4 BP 587 EP 600 DI 10.1175/1520-0450(1996)035<0587:TIOCWO>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UL926 UT WOS:A1996UL92600007 ER PT J AU Zuiker, CD Gruen, DM Krauss, AR AF Zuiker, CD Gruen, DM Krauss, AR TI In situ laser reflectance interferometry measurement of diamond film growth SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SCATTERING; SPECTROSCOPY AB A model is presented to interpret in situ laser reflectance interferometry (LRl) measurements of film growth. The model uses no adjustable parameters and measures film thickness, growth rate, attenuation, and root-mean-square (rms) surface roughness in situ aid in real time. For the particular case of diamond film growth on silicon substrates, it is shown that the assumptions of the model are satisfied, and that film properties determined in situ by LRI and by various means ex situ are in good agreement. With this model, the evolution of diamond film properties are followed under typical diamond growth conditions using mixtures of CH4 and H-2. In agreement with texture formation models, the growth rate and surface roughness were observed to increase as film growth progressed. The growth rate was found to be proportional to CH4 fraction for CH4 fractions less than 8.5%. At higher CH4 fractions, the growth rate decreased and significant attenuation was observed. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP Zuiker, CD (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 19 TC 21 Z9 23 U1 0 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3541 EP 3547 DI 10.1063/1.361406 PG 7 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300027 ER PT J AU Genin, FY Siekhaus, WJ AF Genin, FY Siekhaus, WJ TI Experimental study to validate a model of hillock's formation in aluminum thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID STRESS-RELAXATION; GROWTH AB The growth of holes and hillocks in thin films has been reported extensively and for a multitude of film-substrate systems. A recently developed model [F. Y. Genin, J. Appl. Phys. 77, 5130 (1995)] which analyzes the formation of a ridge at a traveling grain boundary due to stress and capillarity driving forces provides a quantitative description of the growth of the hillocks. In order to test the model, the surface morphology of aluminum thin films deposited on oxidized silicon substrates and annealed at 450 degrees C in argon is investigated; the profiles of thermal hillocks are measured by atomic force microscopy. The comparison shows excellent agreement between modeled and experimental profiles. RP Genin, FY (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 23 TC 17 Z9 17 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3560 EP 3566 PG 7 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300030 ER PT J AU Medlin, DL Friedmann, TA Mirkarimi, PB Cardinale, GF McCarty, KF AF Medlin, DL Friedmann, TA Mirkarimi, PB Cardinale, GF McCarty, KF TI Crystallographic texture in cubic boron nitride thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID STRESS-INDUCED FORMATION; GRAPHITE; DIAMOND; BN AB We examine the crystallographic texture exhibited by cubic boron;nitride (cBN) in thin films grown by ion-assisted deposition. Our analysis indicates that the cBN is preferentially oriented such that individual crystallites have at least one [111] direction lying in the plane of the film but are otherwise randomly oriented about (1) the substrate normal and (2) the in-plane cBN [111] axis. This preferential orientation is consistent with an alignment between the cBN {111} planes and the basal planes of the layer of highly oriented graphitic boron nitride:that forms in the initial stages of film growth. C1 UNIV CALIF DAVIS,DEPT CHEM ENGN & MAT SCI,DAVIS,CA 95616. RP Medlin, DL (reprint author), SANDIA NATL LABS,LIVERMORE,CA 94551, USA. RI McCarty, Kevin/F-9368-2012 OI McCarty, Kevin/0000-0002-8601-079X NR 26 TC 54 Z9 54 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3567 EP 3571 DI 10.1063/1.361381 PG 5 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300031 ER PT J AU Olsen, JA Hu, EL Lee, SR Fritz, IJ Howard, AJ Hammons, BE Tsao, JY AF Olsen, JA Hu, EL Lee, SR Fritz, IJ Howard, AJ Hammons, BE Tsao, JY TI X-ray reciprocal-space mapping of strain relaxation and tilting in linearly graded InAlAs buffers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MOLECULAR-BEAM EPITAXY; RELAXED GEXSI1-X STRUCTURES; III-V COMPOUNDS; 1.3 MU-M; REFLECTANCE MODULATOR; TRANSPORT-PROPERTIES; LOW-TEMPERATURE; GAAS; LAYERS; HETEROSTRUCTURES AB The extent of relaxation and orientation of linearly graded InxAl1-xAs (x = 0.05-0.25) buffers grown on GaAs were examined using a novel x-ray diffraction reciprocal-space mapping technique (kmap). Samples were grown at temperatures ranging from 370 to 550 degrees C. The fractional relaxation of the buffers grown between 470 and 550 degrees C was essentially identical (77%) and symmetric in orthogonal [110] directions. These buffers are believed to be in equilibrium indicating that the incomplete relaxation is not a kinetic effect. The extent of relaxation was less than that expected for equilibrium relaxation in the absence of dislocation-dislocation interactions indicating that such interactions must be considered to accurately predict the extent of relaxation. The saturation of the relaxation as a function of temperature indicates that at the grading rate used (8% In/mu m or 0.69% strain/mu m), we are not working in a growth regime where the relaxation is nucleation limited. In addition, all the buffers are slightly tilted with respect to the GaAs substrate about [110] toward the [1(1) over bar0$] direction suggesting either a bias in the dislocation types in the boule-grown GaAs, or a bias in the way in which alpha and beta dislocations interact with unintentional substrate miscuts. (C) 1996 American Institute of Physics. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Olsen, JA (reprint author), UNIV CALIF SANTA BARBARA,DEPT MAT ENGN,SANTA BARBARA,CA 93107, USA. RI Schaff, William/B-5839-2009 NR 46 TC 52 Z9 52 U1 1 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3578 EP 3584 DI 10.1063/1.361410 PG 7 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300033 ER PT J AU Xie, H Lu, YC Raj, R AF Xie, H Lu, YC Raj, R TI Transmission electron microscopy study of microstructure and misfit dislocations in epitaxial LiTaO3 thin films grown on sapphire by a metalorganic chemical vapor deposition process SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB Epitaxial lithium tantalate thin films were grown on the prismatic plane of sapphire substrates by metalorganic chemical vapor deposition. The film contained two crystallographic variants, both epitaxially oriented with respect to the substrate. The variants were related to each other by 180 degrees rotation about the c axis (which lies in the interface plane). A rectangular misfit dislocation network at the interface was imaged by cross-sectional high-resolution transmission electron microscopy, along two orthogonal directions, and by plan-view weak beam dark field transmission electron microscopy. The Burgers vectors of these two orthogonal sets of misfit dislocations were determined to be 1/3[<1(1)over bar 00>] and 1/3[0001]. The spacing of the dislocations was nearly exactly equal to the ideal values suggesting a very high degree of epitaxy, which was also;confirmed by nearly equal values of the full width at half-maximum of x-ray peaks in the omega scans obtained from the overgrowth and the sapphire substrate. The perfection of the epitaxy is attributed to the lack of multiplicity of slip systems in the interface plane for accommodating the misfit. (C) 1996 American Institute of Physics. C1 NATL SEMICOND CORP,FAIRCHILD RES CTR,SANTA CLARA,CA 95052. LOS ALAMOS NATL LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. RP Xie, H (reprint author), CORNELL UNIV,DEPT MAT SCI & ENGN,ITHACA,NY 14853, USA. NR 11 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3675 EP 3680 DI 10.1063/1.361197 PG 6 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300050 ER PT J AU Tischler, JZ Larson, BC Boatner, LA Alp, EE Mooney, T AF Tischler, JZ Larson, BC Boatner, LA Alp, EE Mooney, T TI Time-sliced Mossbauer absorption spectroscopy using synchrotron radiation and a resonant Bragg monochromator SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DYNAMICAL DIFFRACTION; NUCLEAR; SCATTERING; (FE2O3)-FE-57; CONSTRUCTION; CRYSTAL; RAYS AB Doppler absorption measurements have been used to investigate time-slice Mossbauer absorption spectroscopy for synchrotron radiation and a mosaic resonant Bragg monochromator. The energy widths for wide time intervals and the time-dependent narrowing of the spectral width of resonant Bragg scattering from a mosaic (Fe2O3)-Fe-57 crystal have been measured using a powdered 9.7 mg/cm(2) (Fe2O3)-Fe-57 absorber. The measurements are compared with calculations for a thick (9.7 mg/cm(2)) and a thin (0.5 mg/cm(2)) absorber, and the feasibility of high angular collimation neV range x-ray scattering spectroscopy using synchrotron radiation and time windowing is assessed. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Tischler, JZ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 24 TC 8 Z9 8 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1996 VL 79 IS 7 BP 3686 EP 3690 DI 10.1063/1.361199 PG 5 WC Physics, Applied SC Physics GA UC073 UT WOS:A1996UC07300052 ER PT J AU Hofstadler, SA Bakhtiar, R Smith, RD AF Hofstadler, SA Bakhtiar, R Smith, RD TI Electrospray ionization mass spectrometry .1. Instrumentation and spectral interpretation SO JOURNAL OF CHEMICAL EDUCATION LA English DT Article ID PROTEINS; TIME; DECONVOLUTION; BIOMOLECULES; DISSOCIATION; BIOPOLYMERS; PRINCIPLES; COMPLEXES; ENERGY; IONS C1 PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 43 TC 53 Z9 53 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0021-9584 J9 J CHEM EDUC JI J. Chem. Educ. PD APR PY 1996 VL 73 IS 4 BP A82 EP + PG 6 WC Chemistry, Multidisciplinary; Education, Scientific Disciplines SC Chemistry; Education & Educational Research GA UG477 UT WOS:A1996UG47700001 ER PT J AU Glab, WL Dehmer, PM Dehmer, JL AF Glab, WL Dehmer, PM Dehmer, JL TI Spin-orbit branching ratios for photoionization of the 3d pi gerade states of O-2: Evidence for preferential ionization of the Omega(c)=3/2 core states SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIPHOTON IONIZATION; SELECTIVE-POPULATION; SHAPE RESONANCE; RYDBERG STATES; AUTOIONIZATION; O2; IDENTIFICATION; SPECTROSCOPY; SIGMA AB We have obtained high-resolution photoelectron spectra for eight of the ten 3d pi electronic states of O-2, using a rotationally resolved, two-color 2+1' excitation and ionization scheme. A magnetic bottle photoelectron spectrometer, used to acquire the spectra, provided a resolution sufficient to observe the yields of the individual spin-orbit states of the ground electronic state of the ion. Branching ratios were obtained from the spectra for three different photoionization wavelengths. The overall behavior of the branching ratios for different electronic states can be explained by calculating the core state composition of the intermediate states, taking into account the spin-orbit mixing of Hund's case (a) basis states, and assuming that electronic states having the core state Omega(c)=3/2 have a larger photoionization probability than those having an Omega(c)=1/2 core. (C) 1996 American Institute of Physics. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Glab, WL (reprint author), TEXAS TECH UNIV,DEPT PHYS,POB 41051,LUBBOCK,TX 79409, USA. NR 16 TC 16 Z9 16 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1996 VL 104 IS 13 BP 4937 EP 4944 DI 10.1063/1.471126 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900007 ER PT J AU Parsapour, F Kelley, DF Craft, S Wilcoxon, JP AF Parsapour, F Kelley, DF Craft, S Wilcoxon, JP TI Electron transfer dynamics in MoS2 nanoclusters: Normal and inverted behavior SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SEMICONDUCTOR PARTICULATE SYSTEMS; RAMAN-SCATTERING; COLLOIDAL CDS; SENSITIZATION; CRYSTALLITES; FLUORESCENCE; MICROCRYSTALS; CLUSTERS; SURFACES; WSE2 AB The photophysics and electron transfer (ET) dynamics of quantum confined MoS2 nanoclusters have been studied using static and time resolved emission spectroscopy. The MoS2 nanoclusters consist of a single S-Mo-S trilayer, having diameters of similar to 2.5 or 4.5 nm. Two types of electron accepters are adsorbed on these nanoclusters: 2,2'-bipyridine (bpy) and 4,4',5,5'-tetramethyl-2,2'-bipyridine (TMB). The ET reaction exothermicities may be varied by changing the electron acceptor or by varying the size of the MoS2 nanocluster. TMB is harder to reduce, and thus has a smaller ET driving force than bpy. The smaller nanoclusters have a higher energy conduction band, and thus have a larger ET driving force. In all cases, the ET driving force may be calculated from bulk MoS2 properties and quantum confinement theory. Both ''normal'' and ''inverted'' behaviors are observed. A reorganization energy of 0.40 eV is calculated from energy dependent ET rates. (C) 1996 American Institute of Physics. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87108. RP Parsapour, F (reprint author), COLORADO STATE UNIV,DEPT CHEM,FT COLLINS,CO 80523, USA. NR 57 TC 51 Z9 51 U1 8 U2 32 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1996 VL 104 IS 13 BP 4978 EP 4987 DI 10.1063/1.471128 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900011 ER PT J AU Roncero, O Gray, SK AF Roncero, O Gray, SK TI Quantum dynamics of ArI2 vibrational predissociation including low total angular momenta: The role of intramolecular vibrational energy redistribution SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VANDERWAALS MOLECULES; PHOTO-DISSOCIATION; WAVE-PACKET; IODINE; PHOTOFRAGMENTATION; SPECTROSCOPY; SCATTERING; COMPLEXES; EVOLUTION; EQUATION AB Full-dimensional quantum dynamics calculations on ArI2(B,v(i)) vibrational predissociation with total angular momenta J=0, 1, and 2 are presented. Models based on a few interacting states are shown to reproduce important aspects of the dynamics, confirming that vibrational predissociation is mediated by a few-state intramolecular vibrational energy redistribution effect. As a consequence, vibrational predissociation rate constants exhibit large oscillations with v(i), the initial I-2 vibrational quantum number in the complex. The qualitative effect persists when alternative choices for the interaction potential parameters are considered. Similarly, despite the importance of Coriolis coupling, the effect persists as J is varied from 0 to 2. We also discuss how the effect may be difficult to observe in typical experiments that involve higher J values. (C) 1996 American Institute of Physics. C1 ARGONNE NATL LAB,DIV CHEM,THEORET CHEM GRP,ARGONNE,IL 60439. RP Roncero, O (reprint author), CSIC,INST MATEMAT & FIS FUNDAMENTAL,SERRANO 123,E-28006 MADRID,SPAIN. RI Roncero, Octavio/K-1872-2014 OI Roncero, Octavio/0000-0002-8871-4846 NR 44 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1996 VL 104 IS 13 BP 4999 EP 5011 DI 10.1063/1.471267 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900013 ER PT J AU vanThiel, M Ree, FH AF vanThiel, M Ree, FH TI Accurate high-pressure and high-temperature effective pair potentials for the systems N-2-N and O-2-O SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRICAL-CONDUCTIVITY; LIQUID-NITROGEN; HIGH-DENSITY; MIXTURES; OXYGEN; COMPRESSION; TRANSITION; EQUATION; STATE AB Statistical mechanical chemical equilibrium calculations of N-2 and O-2 show that these molecules dissociate behind strong shock waves. Our determination of accurate intermolecular potentials has required the consideration of the dissociation products N and O. Our previous theoretical efforts to predict the thermodynamic properties of these molecules relied in part on corresponding states theory and shock wave data of argon, without consideration of the dissociation products. Recent high-pressure Hugoniot measurements, however, allowed a more accurate determination of the potentials and the explicit inclusion of the dissociation products. The best fit to the data is obtained with the exponential-6 coefficients, for O-2-O-2: epsilon/k=125 K, r*=3.86 Angstrom, alpha=13.2; for O-O: epsilon/k=700 K, r*=2.40 Angstrom, alpha=11.0; for N-2-N-2: epsilon/k=293 K, r*=3.91 Angstrom, alpha=11.5; and for N-N: epsilon/k=600 K, r*=2.47 Angstrom, alpha=10.0. The unlike pair interactions are obtained from these like interactions with a modified Lorentz-Berthelot rule. The coefficients in the modified Lorentz-Berthelot equations are k/l/m=1/1/0.93 for O-2-O- and k/l/m=1/1/0.90 for N-2-N interactions. (C) 1996 American Institute of Physics. RP vanThiel, M (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 21 TC 20 Z9 20 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 APR 1 PY 1996 VL 104 IS 13 BP 5019 EP 5025 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900015 ER PT J AU Osborn, DL Leahy, DJ Cyr, DR Neumark, DM AF Osborn, DL Leahy, DJ Cyr, DR Neumark, DM TI Photodissociation spectroscopy and dynamics of the N2O2- anion SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LASER PHOTO-DISSOCIATION; FLIGHT MASS-SPECTROMETER; MOLECULAR NEGATIVE-IONS; VIBRATIONAL-SPECTRA; MATRIX-ISOLATION; SOLID NEON; PHOTODETACHMENT; DISCHARGE; METAL; BEAM AB The spectroscopy and dissociation dynamics of the N2O2-(C-2v) anion have been investigated using the technique of fast ion beam translational spectroscopy, A newly developed pulsed supersonic discharge source is described for the production of internally cold N2O2-. A structured absorption band beginning near 580 nm is observed, and is assigned to the (B) over tilde((2)A(2))<--(X) over tilde(B-2(2)) transition with the aid of ab initio calculations. Two dissociation channels from the upper state are observed: (1) O-+N2O and (2) NO-+NO. Translational energy and angular distributions are measured for both channels at several excitation energies. The translational energy distribution for channel (1) at 570 nm shows resolved structure corresponding to N2O vibrational excitation. The translational energy distributions for channel (1) are reasonably well described by prior distributions, indicating this channel results from dissociation from the N2O2- ground electronic state. In contrast, channel (2) appears to result from dissociation on a repulsive excited electronic state. From the translational energy distributions for channel (1), we obtain the bond dissociation energy and heat of formation (at 0 K) for N2O2-: D-0(O-N2O)=1.40+/-0.03 eV and Delta H-f,0(0)(N2O2-)=0.58+/-0.04 eV. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Osborn, DL (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Osborn, David/A-2627-2009; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 48 TC 63 Z9 63 U1 4 U2 23 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1996 VL 104 IS 13 BP 5026 EP 5039 DI 10.1063/1.471132 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900016 ER PT J AU Curtiss, LA Redfern, PC Smith, BJ Radom, L AF Curtiss, LA Redfern, PC Smith, BJ Radom, L TI Gaussian-2 (G2) theory: Reduced basis set requirements SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-ENERGIES; 2ND-ROW COMPOUNDS; 1ST-ROW AB Two variations of G2(MP2) theory which employ smaller basis sets in evaluating the quadratic configuration interaction [QCISD(T)] component of the energy are presented. The first, G2(MP2,SVP), uses the split-valence plus polarization (SVP) 6-31G(d) basis, while the second, G2(MP2,SV), uses the split-valence (SV) 6-31G basis. The methods are evaluated on the basis of results for the set of 125 systems used for testing G2 theory. The mean absolute deviation of G2(MP2,SVP) results from experimental values is 1.63 kcal mol(-1) compared with 1.58 and 1.21 kcal mol(-1) for G2(MP2) and G2, respectively. The G2(MP2,SVP) method thus provides results which are generally very similar in quality to those obtained from G2(MP2) but at considerably reduced computational expense. On the other hand, the mean absolute deviation of G2(MP2,SV) results from experiment is substantially larger (2.13 kcal mol(-1)). The G2(MP2,SV) method exceeds the 2 kcal mol(-1) target accuracy of G2 theory for an unacceptably large number of comparisons. (C) 1996 American Institute of Physics. C1 BIOMOL RES INST,PARKVILLE,VIC 3052,AUSTRALIA. AUSTRALIAN NATL UNIV,RES SCH CHEM,CANBERRA,ACT 0200,AUSTRALIA. RP Curtiss, LA (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Smith, Brian/F-8282-2011 OI Smith, Brian/0000-0003-0498-1910 NR 17 TC 221 Z9 223 U1 1 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 APR 1 PY 1996 VL 104 IS 13 BP 5148 EP 5152 DI 10.1063/1.471141 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900027 ER PT J AU Stevens, MJ Falk, ML Robbins, MO AF Stevens, MJ Falk, ML Robbins, MO TI Interactions between charged spherical macroions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; POISSON-BOLTZMANN APPROXIMATION; ELECTRIC DOUBLE-LAYERS; HYPERNETTED-CHAIN; PHASE-DIAGRAM; ELECTROSTATIC INTERACTION; COLLOIDAL SUSPENSIONS; STATIC CORRELATIONS; NEUTRON-SCATTERING; POLY-ELECTROLYTES AB Monte Carlo (MC) simulations were used to study the screened interactions between charged spherical macroions surrounded by discrete counterions, and to test previous theories of screening. The simulations were performed in the primitive cell of the bcc lattice, and in the spherical Wigner-Seitz cell that is commonly used in approximate calculations. We found that the Wigner-Seitz approximation is valid even at high volume fractions phi and large macroion charges Z, because the macroion charge becomes strongly screened. Pressures calculated from Poisson-Boltzmann theory and local density functional theory deviate from MC values as phi and Z increase, but continue to provide upper and lower bounds for the MC results. While Debye-Huckel (DH) theory fails badly when the bare charge is used, MC pressures can be fit with an effective DH charge, Z(DH), that is nearly independent of volume fraction. As Z diverges, Z(DH) saturates at z psi(max)R(m)/lambda, where z is the counterion charge, R(m) is the macroion radius, lambda is the Bjerrum length, and psi(max) is a constant of order 10. (C) 1996 American Institute of Physics. C1 JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. RP Stevens, MJ (reprint author), SANDIA NATL LABS, PARALLEL COMPUTAT SCI DEPT, POB 5800, MS 1111, ALBUQUERQUE, NM 87185 USA. RI Falk, Michael/A-8478-2008 OI Falk, Michael/0000-0002-8383-4259 NR 56 TC 118 Z9 119 U1 1 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 1 PY 1996 VL 104 IS 13 BP 5209 EP 5219 DI 10.1063/1.471148 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900034 ER PT J AU Chialvo, AA AF Chialvo, AA TI On the realism of the re-engineered simple point charge water model SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; POLARIZABLE WATER; COMPUTER-SIMULATION AB The realism of the recently proposed high-temperature reparameterization of the simple point charge (SPC) water model [C. D. Berweger, W. F. van Gunsteren, and F. Muller-Plathe, Chem. Phys. Lett. 232, 429 (1995)] is tested by comparing the simulated microstructure and dielectric properties to the available experimental data. The test indicates that the new parameterization fails dramatically to describe the microstructural and dielectric properties of water at high temperature: it predicts rather strong short-range site-site pair correlations, even stronger than those for water at ambient conditions, and a threefold smaller dielectric constant. Moreover, the resulting microstructure suggests that the high-temperature force-field parameters would predict a twofold higher critical density. The failure of the high-temperature parameterization is analyzed and some suggestions on alternative choices of the target properties for the weak-coupling are discussed. (C) 1996 American Institute of Physics. C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. RP Chialvo, AA (reprint author), UNIV TENNESSEE,DEPT CHEM ENGN,KNOXVILLE,TN 37996, USA. OI Chialvo, Ariel/0000-0002-6091-4563 NR 28 TC 17 Z9 17 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 APR 1 PY 1996 VL 104 IS 13 BP 5240 EP 5243 DI 10.1063/1.471665 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA UD669 UT WOS:A1996UD66900037 ER PT J AU Balding, DJ Torney, DC AF Balding, DJ Torney, DC TI Optimal pooling designs with error detection SO JOURNAL OF COMBINATORIAL THEORY SERIES A LA English DT Article AB Consider a collection of objects, some of which may be ''bad,'' and a lest which determines whether or not a given subcollection contains no bad objects. The nonadaptive pooling (or group testing) problem involves identifying the bad objects using the least number of tests applied in parallel. The ''hypergeometric'' case occurs when an upper bound on the number of bad objects is known a priori. Here, practical considerations lead us to impose the additional requirement of a posteriori confirmation that the bound is satisfied. A generalization of the problem in which occasional errors in the test outcomes can occur is also considered. Optimal solutions to the general problem are shown to be equivalent to maximum-size collections of subsets of a finite set satisfying a union condition which generalizes that considered by Erdos and co-workers. Lower bounds on the number of tests required are derived when the number of bad objects is believed to be either 1 or 2. Steiner systems are shown to be optimal solutions in some cases. (C) 1996 Academic Press, Inc. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Balding, DJ (reprint author), UNIV LONDON QUEEN MARY & WESTFIELD COLL,SCH MATH SCI,MILE END RD,LONDON E1 4NS,ENGLAND. RI Balding, David/G-9898-2011 OI Balding, David/0000-0002-1480-6115 NR 8 TC 33 Z9 36 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 0097-3165 J9 J COMB THEORY A JI J. Comb. Theory Ser. A PD APR PY 1996 VL 74 IS 1 BP 131 EP 140 DI 10.1006/jcta.1996.0041 PG 10 WC Mathematics SC Mathematics GA UE195 UT WOS:A1996UE19500009 ER PT J AU Sackinger, PA Schunk, PR Rao, RR AF Sackinger, PA Schunk, PR Rao, RR TI A newton-raphson pseudo-solid domain mapping technique for free and moving boundary problems: A finite element implementation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID FREE-SURFACE; COATING FLOW; SOLIDIFICATION; SHAPE; WALL AB An implicit, pseudo-solid domain mapping technique is described that facilitates finite element analysis of free and moving boundary problems. The technique is based on an implicit, full-Newton strategy,free of restrictions on mesh structure; this leads to many advantages over existing domain mapping techniques. The fully coupled approach using Newton's method is particularly effective for problems with strong coupling between the internal bulk physics and the governing physics at unknown free boundary locations. It is also useful when the distinguishing conditions which constrain the free boundary shape provide only an implicit dependence on the boundary location. Unstructured meshes allow for efficient resolution of internal and boundary layers and other regions of strong local variations in the solution and they also reduce the amount of user interaction required to define a problem since the meshes may be generated automatically. The technique is readily applied to steady or transient problems in complex geometries of two and three dimensions. Examples are shown that include free and moving boundary problems from solidification and capillary hydrodynamics. (C) 1996 Academic Press, Inc. RP Sackinger, PA (reprint author), SANDIA NATL LABS,MFG & ENVIRONM FLUID DYNAM DEPT 1511,ALBUQUERQUE,NM 87185, USA. NR 48 TC 102 Z9 103 U1 1 U2 9 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR PY 1996 VL 125 IS 1 BP 83 EP 103 DI 10.1006/jcph.1996.0081 PG 21 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA UD288 UT WOS:A1996UD28800007 ER PT J AU Wereszczak, AA Ferber, MK Kirkland, TP Lin, CKJ AF Wereszczak, AA Ferber, MK Kirkland, TP Lin, CKJ TI Effect of cyclic loading on the creep performance of silicon nitride SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 40th International Gas Turbine and Aeroengine Congress and Exhibition CY JUN 05-08, 1995 CL HOUSTON, TX AB Tension-tension cyclic fatigue tests (triangular waveform, sigma(max) = 100 MPa, R = 0.1) were conducted on hot isostatically pressed (HIPed) silicon nitride at frequencies spanning several orders of magnitude (5.6 X 10(-6) to 0.1 Hz or 10(-3) MPa/s to 18 MPa/s) at 1370 degrees C in air. The amount of cyclic creep strain was found to be a function of the frequency or stressing rare, with greater strains to failure observed as the frequency or stressing rate decreased. The total strain was viewed as the sum of elastic, anelastic (or transient recoverable), and plastic (viscous or nonrecoverable) strain contributions, after the empirical Pao and Marin model. The plastic strain was found to be the dominant component of the total creep and was unsatisfactorily represented by the Pao and Marin model. To circumvent this, a time exponent was introduced in the plastic strain term in the Pao and Marin model. This modification resulted in good correlation between model and experiment at the slower frequencies examined but overpredicted the cyclic creep strain at the faster frequencies. The utility of using the modified Pao and Marin model to predict cyclic creep response from static creep and strain relaxation tests is described. C1 NATL CENT UNIV,DEPT MECH ENGN,CHUNGLI 32054,TAIWAN. RP Wereszczak, AA (reprint author), OAK RIDGE NATL LAB,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831, USA. RI Wereszczak, Andrew/I-7310-2016 OI Wereszczak, Andrew/0000-0002-8344-092X NR 15 TC 2 Z9 2 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD APR PY 1996 VL 118 IS 2 BP 251 EP 256 DI 10.1115/1.2816585 PG 6 WC Engineering, Mechanical SC Engineering GA UJ384 UT WOS:A1996UJ38400005 ER PT J AU Murray, PE AF Murray, PE TI A model of residual stress in the fabrication of thin glass films SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID THERMAL-OXIDATION; VISCOUS-FLOW; SIO2; SILICON AB We investigate the residual stress which occurs during fabrication of thin glass films. This research involves an innovative approach to modeling of residual stress which will be used to resolve important scientific issues related to the manufacturing of thin glass films for semiconductor devices. The validity of our results is confirmed by comparing analytical predictions of stress in glass films and experimental data reported previously. RP LOCKHEED IDAHO TECHNOL CO, IDAHO NATL ENGN LAB, MAIL STOP 3808, IDAHO FALLS, ID 83415 USA. NR 23 TC 0 Z9 0 U1 0 U2 1 PU ASME PI NEW YORK PA TWO PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-4289 EI 1528-8889 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1996 VL 118 IS 2 BP 213 EP 216 DI 10.1115/1.2804889 PG 4 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA UH508 UT WOS:A1996UH50800010 ER PT J AU Mauro, T Rassner, U Bench, G Feingold, KR Elias, PM AF Mauro, T Rassner, U Bench, G Feingold, KR Elias, PM TI Acute barrier disruption causes quantitative changes in the calcium gradient. SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT DERMATOL,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 1996 VL 106 IS 4 BP 681 EP 681 PG 1 WC Dermatology SC Dermatology GA UC787 UT WOS:A1996UC78700719 ER PT J AU Culf, AS Morimoto, H Williams, PG Lockley, WJS Primrose, WU Jones, JR AF Culf, AS Morimoto, H Williams, PG Lockley, WJS Primrose, WU Jones, JR TI Synthesis of a tritium labelled phospholipase A(2) inhibitor: A ligand for macromolecular H-3 NMR spectroscopy SO JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS LA English DT Article DE diimide; Wilkinson's catalyst; tritium; tritium NMR; PLA(2); inhibitor ID TRANSITION-STATE ANALOG; VENOM PHOSPHOLIPASE-A2; CRYSTAL-STRUCTURE; COMPLEX; BINDING; ENZYME; PANCREAS AB A tritium labelled phospholipase A(2) (PLA(2)) amide analogue inhibitor was prepared by the reduction of an alkene precursor. Diimide, heterogeneous and homogeneous metal catalyzed reduction methods were assessed for their suitability for the preparation of a tritiated ligand for H-3 NMR spectroscopic studies. The chosen homogeneous metal-catalyzed method gave a product of specific activity 57 Ci mmol(-1), which was isolated by flash chromatography. The binding of this tritiated substrate to bovine pancreatic PLA(2) was observed by H-3 NMR spectroscopy in the presence of calcium ions. Chemical shift changes suggest that the tritium atoms are located within the hydrophobic pocket of the protein, close to two phenylalanine residues. C1 UNIV SURREY,DEPT CHEM,GUILDFORD GU2 5XH,SURREY,ENGLAND. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV STRUCT BIOL,NATL TRITIUM LABELLING FACIL,BERKELEY,CA 94720. UNIV LEICESTER,DEPT BIOCHEM,LEICESTER LE1 7RH,LEICS,ENGLAND. ASTRA CHARNWOOD,DEPT MED CHEM,LOUGHBOROUGH LE11 0RH,LEICS,ENGLAND. NR 25 TC 5 Z9 5 U1 1 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0362-4803 J9 J LABELLED COMPD RAD JI J. Label. Compd. Radiopharm. PD APR PY 1996 VL 38 IS 4 BP 373 EP 384 DI 10.1002/(SICI)1099-1344(199604)38:4<373::AID-JLCR844>3.0.CO;2-U PG 12 WC Biochemical Research Methods; Chemistry, Medicinal; Chemistry, Analytical SC Biochemistry & Molecular Biology; Pharmacology & Pharmacy; Chemistry GA UD879 UT WOS:A1996UD87900007 ER PT J AU Barat, K AF Barat, K TI Obtaining laser safety at a synchrotron radiation user facility: The advanced light source SO JOURNAL OF LASER APPLICATIONS LA English DT Article DE laser safety; synchrotron radiation; user facility AB The Advanced Light Source (ALS) is a United States national facility for scientific research and development located at the Lawrence Berkeley National Laboratory in California. The ALS delivers the worlds brightest synchrotron radiation in the far ultraviolet and soft X-ray regions of the spectrum. As a 'user facility' it is available to researchers from industry, academia, and laboratories from around the world. Subsequently, a wide range of safety concerns become involved. This article relates not only to synchrotron facilities but to any 'user' facility. A growing number of US centers are attracting organizations and individuals to use the equipment on site, for a fee. This includes synchrotron radiation and/or free electron facilities, specialty research centers, and laser job shops. Personnel coming to such a facility bring with them a broad spectrum of safety cultures. Upon entering, the guests must accommodate to the host facility safety procedures. This article describes a successful method to deal with that responsibility. RP Barat, K (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,MS 90-2148,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU LASER INST AMER PI ORLANDO PA 12424 RESEARCH PARKWAY SUITE 125, ORLANDO, FL 32826 SN 1042-346X J9 J LASER APPL JI J. Laser Appl. PD APR PY 1996 VL 8 IS 2 BP 109 EP 114 PG 6 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA UQ348 UT WOS:A1996UQ34800008 ER PT J AU Jellison, JL Cieslak, MJ AF Jellison, JL Cieslak, MJ TI Laser materials processing at Sandia National Laboratories SO JOURNAL OF LASER APPLICATIONS LA English DT Article AB This paper describes the laser materials processing capabilities at Sandia National Laboratories. Some of the advances in the understanding of various aspects of laser materials processing which have been made by the laser materials processing team at Sandia are discussed. RP Jellison, JL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU LASER INST AMER PI ORLANDO PA 12424 RESEARCH PARKWAY SUITE 125, ORLANDO, FL 32826 SN 1042-346X J9 J LASER APPL JI J. Laser Appl. PD APR PY 1996 VL 8 IS 2 BP 115 EP 119 PG 5 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA UQ348 UT WOS:A1996UQ34800009 ER PT J AU Boyle, E Small, DM Gantz, D Hamilton, JA German, JB AF Boyle, E Small, DM Gantz, D Hamilton, JA German, JB TI Monoacylglycerols alter the lipid composition and molecular mobility of phosphatidylcholine bilayers: C-13 NMR evidence of dynamic lipid remodeling SO JOURNAL OF LIPID RESEARCH LA English DT Article DE monopalmitin; monoolein; C-13 NMR; remnant uptake; lipoprotein lipase ID NUCLEAR MAGNETIC-RESONANCE; CHYLOMICRON-LIKE EMULSIONS; PHOSPHOLIPID-BILAYERS; CHOLESTERYL OLEATE; LIPOPROTEIN-LIPASE; SERUM-ALBUMIN; OLEIC-ACID; SOLUBILIZATION; TRIOLEIN; METABOLISM AB The physical effects of monoacylglycerols (MAG) in small unilamellar vesicles composed of phosphatidylcholine (PC), triolein, cholesterol, and varying amounts of monopalmitin and monoolein were studied by C-13-NMR. The signal to noise ratio of the carbonyls of PC and triolein were enhanced by the addition of 1,2-di-[1-C-13]palmitoylphosphatidylcholine and tri-[1-C-13]oleoylglycerol. The linewidths of the carbonyl- (13), choline methyl, olefinic carbon, and terminal methyl resonances were measured digitally from vesicles with 0 to 42 mol % of MAG. Significant increases in the linewidth of carbonyl (P < 0.05), olefinic and terminal methyl carbons (P < 0.01) of vesicles containing 42 mol % monopalmitin indicated that these groups experienced restricted molecular mobility at high monopalmitin concentrations. However, more striking was the apparent displacement of triolein from the surface environment of PC bilayers to an oil-like environment in systems containing only 8 mol % monopalmitin. Displacement of triolein from the surface by monoolein occurred only above 15 mol %. Thus, saturated and monounsaturated monoacylglycerols, natural products of lipoprotein metabolism, dynamically alter both the lipid composition and molecular mobility of lipoprotein surfaces in distinct ways.-Boyle, E., D. M. Small, D. Gantz, J. A. Hamilton, and J. B. German. Monoacylglycerols alter the lipid composition and molecular mobility of phosphatidylcholine bilayers: C-13 NMR evidence of dynamic lipid remodeling. C1 BOSTON UNIV,SCH MED,DEPT BIOPHYS,BOSTON,MA 02118. LAWRENCE LIVERMORE NATL LAB,DEPT FOOD SCI & TECHNOL,DAVIS,CA 95616. FU PHS HHS [2P01-26335] NR 36 TC 7 Z9 7 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 APR PY 1996 VL 37 IS 4 BP 764 EP 772 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UJ400 UT WOS:A1996UJ40000006 PM 8732776 ER PT J AU Schwerk, U Michel, D Pruski, M AF Schwerk, U Michel, D Pruski, M TI Local magnetic field distribution in a polycrystalline sample exposed to a strong magnetic field SO JOURNAL OF MAGNETIC RESONANCE SERIES A LA English DT Article ID NMR; RESOLUTION; SOLIDS AB A model for a polycrystalline material is proposed to describe the local magnetic field distribution that gives rise to susceptibility broadening in nuclear magnetic resonance. The following contributions to the broadening have been accounted for: (i) broadening due to various orientations of the crystallites containing the resonating spin; (ii) broadening due to different orientations of neighboring crystallites; and (iii) broadening due to variations in the distribution of neighboring crystallites. The effect of each contribution on the NMR spectra taken with and without magic angle spinning has been studied for axially symmetric susceptibility tensors. Numerical simulations of the overall magnetic field distribution have been carried out for different packing densities and anisotropies Delta(chi) of the susceptibility tensor. The overall field distribution appeared to be symmetric with a first moment that is not affected by the presence of neighboring crystallites. The MAS line-narrowing factor was found to decrease for higher packing density and increasing Delta(chi). The proposed method also allows the calculation of local gradients associated with the local magnetic fields, H-1 NMR experiments on adsorbed molecules in NaX zeolite have been used to test the proposed model and to examine the limitations that magnetic susceptibility forces upon spectral resolution. (C) 1996 Academic Press, Inc. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP Schwerk, U (reprint author), UNIV LEIPZIG,FAK PHYS & GEOWISSENSCH,LINNESTR 5,D-04103 LEIPZIG,GERMANY. NR 14 TC 31 Z9 31 U1 0 U2 8 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 1064-1858 J9 J MAGN RESON SER A JI J. Magn. Reson. Ser. A PD APR PY 1996 VL 119 IS 2 BP 157 EP 164 DI 10.1006/jmra.1996.0068 PG 8 WC Physics, Atomic, Molecular & Chemical SC Physics GA UJ398 UT WOS:A1996UJ39800002 ER PT J AU Hjortstam, O Trygg, J Wills, JM Johansson, B Eriksson, O AF Hjortstam, O Trygg, J Wills, JM Johansson, B Eriksson, O TI Giant surface layer relaxation for be (10(1)over-bar-0) SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Symposium on Metallic Multilayers (MML 95) CY SEP 11-14, 1995 CL CAVENDISH LAB, CAMBRIDGE, ENGLAND HO CAVENDISH LAB ID BE(0001) AB We predict a giant surface relaxation of the (<10(1)over bar 0>) surface of Be. The surface layer relaxes inwards with 25%, which we show is due to a pronounced surface state close to the Fermi level. We also predict that the (<10(1)over bar 0>) surface at Be is terminated such that the surface has 8 nearest neighbours (A termination). C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Hjortstam, O (reprint author), UNIV UPPSALA,DEPT PHYS,CONDENSED MATTER THEORY GRP,BOX 530,S-75121 UPPSALA,SWEDEN. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 8 TC 0 Z9 0 U1 0 U2 0 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 APR PY 1996 VL 156 IS 1-3 BP 85 EP 86 DI 10.1016/0304-8853(95)00798-9 PG 2 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA UV358 UT WOS:A1996UV35800038 ER PT J AU Bader, SD Li, DQ AF Bader, SD Li, DQ TI Magneto-optical and photoemission studies of ultrathin wedges SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Symposium on Metallic Multilayers (MML 95) CY SEP 11-14, 1995 CL CAVENDISH LAB, CAMBRIDGE, ENGLAND HO CAVENDISH LAB ID FILMS AB Magnetic phase transitions of Fe wedges grown epitaxially on Cu(100) are detected via the surface magneto-optical Kerr effect and used to construct a phase diagram for face centered Fe. Also, the confinement of Cu sp- and d-quantum-well states is studied for Cu/Co(wedge)/Cu(100) utilizing undulator-based photoemission experiments. RP Bader, SD (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013 NR 7 TC 6 Z9 6 U1 0 U2 2 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 APR PY 1996 VL 156 IS 1-3 BP 153 EP 157 DI 10.1016/0304-8853(95)00823-3 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA UV358 UT WOS:A1996UV35800064 ER PT J AU Kortright, JB AF Kortright, JB TI Status and limitations of multilayer X-ray interference structures SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 2nd International Symposium on Metallic Multilayers (MML 95) CY SEP 11-14, 1995 CL CAVENDISH LAB, CAMBRIDGE, ENGLAND HO CAVENDISH LAB ID CORRELATED INTERFACIAL ROUGHNESS; TUNGSTEN-CARBON; DIFFRACTION; SCATTERING; MIRRORS; FILMS; REFLECTION AB Trends in the performance of X-ray multilayer interference structures with periods ranging from 9 to 130 Angstrom are reviewed. Analysis of near-normal incidence reflectance data versus photon energy reveals that the effective interface width sigma in a static Debye-Waller model, describing interdiffusion and roughness, decreases as the multilayer period decreases, and reaches a lower limit of roughly 2 Angstrom. Specular reflectance and diffuse scattering from uncoated and multilayer-coated substrates having different roughnesses suggest that this lower limit results largely from substrate roughness. The increase in interface width with period thus results from increasing roughness or interdiffusion as the layer thickness increases. RP Kortright, JB (reprint author), LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720, USA. NR 27 TC 7 Z9 7 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 APR PY 1996 VL 156 IS 1-3 BP 271 EP 275 DI 10.1016/0304-8853(95)00866-7 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA UV358 UT WOS:A1996UV35800114 ER PT J AU Wolfenden, A Kury, PB Petrovic, JJ AF Wolfenden, A Kury, PB Petrovic, JJ TI Measurement of dynamic young's modulus for molybdenum disilicide/pentatitanium trisilicide SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE ceramics; composites; elastic; intermetallics; molybdenum disilicide; pentatitanium trisilicide; temperature; ultrasonics; Young's modulus ID NI-AL; TEMPERATURE AB The PUCOT (piezoelectric ultrasonic composite oscillator technique) has been used to measure the temperature dependence of dynamic Young's modulus of molybdenum disilicide (MoSi2) reinforced with 10, 30, and 50% volume fraction of pentatitanium trisilicide (Ti5Si3). The temperature ranges were room temperature to 600 degrees C for the 30 and 50% specimens, and room temperature to 880 degrees C for the 10% specimens. In all cases, the values of Young's modulus decreased linearly with increasing temperature, although at different rates. A graph of Young's modulus versus composition was used to estimate the value of Young's modulus for MoSi2. The value obtained (385 GPa) was in excellent agreement with the value of 388 GPa quoted in the literature. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Wolfenden, A (reprint author), TEXAS A&M UNIV,DEPT MECH ENGN,ADV MAT LAB,COLLEGE STN,TX 77843, USA. NR 10 TC 2 Z9 2 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD APR PY 1996 VL 5 IS 2 BP 232 EP 234 DI 10.1007/BF02650892 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA UC568 UT WOS:A1996UC56800009 ER PT J AU Swisher, JH Jhunjhunwala, M GasperGalvin, LD Gardner, TH Hammerbeck, K AF Swisher, JH Jhunjhunwala, M GasperGalvin, LD Gardner, TH Hammerbeck, K TI Properties of sulfur sorbents containing dispersed nickel in an Al2O3 matrix SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE coal gasification; desulfurization; nickel ID GASES AB For advanced coal gasification systems, regenerable sorbents are being developed to remove sulfur (S) from the hot product gas prior to its use in gas turbines and high-temperature fuel cells. Whereas zinc (Zn) base sorbents are attractive for these applications, they have limitations in high-temperature capability and in durability. Materials containing dispersed nickel (Ni) in an Al2O3 matrix have the potential to be better in both respects. Their main limitation is that they do not reduce H2S concentrations to the low parts per million (ppm) level. Results are reported here on the second phase of a program on dispersed Ni sorbents. Included are the results of crush strength, thermogravimetric analysis, and fixed-bed reactor experiments. An important conclusion drawn from the results is that chemisorption of H2S plays a major role in reducing its concentration in gas exiting the bed below the levels expected from the Ni-Ni sulfide equilibrium. C1 US DOE,MORGANTOWN ENERGY TECHNOL CTR,MORGANTOWN,WV 26507. OAK RIDGE ASSOCIATED UNIV,OAK RIDGE,TN 37830. RP Swisher, JH (reprint author), SO ILLINOIS UNIV,CARBONDALE,IL 62901, USA. NR 23 TC 4 Z9 4 U1 1 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD APR PY 1996 VL 5 IS 2 BP 247 EP 255 DI 10.1007/BF02650895 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA UC568 UT WOS:A1996UC56800012 ER PT J AU Esherick, P AF Esherick, P TI Introduction SO JOURNAL OF MATERIALS RESEARCH LA English DT Editorial Material RP Esherick, P (reprint author), SANDIA NATL LABS,CHEM PROC SCI DEPT,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 2 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 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1996 VL 11 IS 4 BP 783 EP 785 DI 10.1557/JMR.1996.0094 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA UE459 UT WOS:A1996UE45900001 ER PT J AU Gao, Y Chambers, SA AF Gao, Y Chambers, SA TI Effect of substrate orientation on the crystal quality and surface roughness of Nb-doped TiO2 epitaxial films on TiO2 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB We have grown Nb-doped TiO2 epitaxial films on (100) and (110)-oriented TiO2 rutile substrates by molecular beam epitaxy. Nb substitutionally incorporates at cation sites in the rutile lattice, forming NbxTi1-xO2 solid solutions. However, the crystal quality and surface roughness of the films depend strongly on the substrate orientation. Surface roughening and defect formation occur at lower values of x on (100) than on (110). This result is due to anisotropic changes in the metal-oxygen bond lengths within the rutile structure in going from TiO2 to NbO2; there are 1% and 12% changes in the metal atom to octahedron-base oxygen and metal atom to octahedron-vertex oxygen bond lengths, respectively. Every metal atom in the (100) growth surface has in-plane components of the 12% mismatch. However, only half of the metal atoms in the (110) growth plane have such components. Thus, there is substantially larger in-plane lattice mismatch when the growth surface is (100) compared to (110), resulting in surface roughening and formation of defects at a lower doping level for (100)-oriented NbxTi1-xO2 epitaxial films. RP Gao, Y (reprint author), PACIFIC NW LAB, ENVIRONM MOLEC SCI LAB, POB 999, MS K2-12, RICHLAND, WA 99352 USA. NR 23 TC 13 Z9 13 U1 2 U2 8 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 APR PY 1996 VL 11 IS 4 BP 1025 EP 1029 DI 10.1557/JMR.1996.0128 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA UE459 UT WOS:A1996UE45900035 ER PT J AU Gale, WF Nemani, RV Horton, JA AF Gale, WF Nemani, RV Horton, JA TI The influence of ageing on the stability of beta-gamma/gamma' derived microstructures in Ni-Al-Cr-(Co) alloys SO JOURNAL OF MATERIALS SCIENCE LA English DT Article AB Multiphase Ni-Al-(Fe)-(Cr)-(Co)-based intermetallics with beta(B2)-gamma (A1)/gamma'(L1(2)), beta-gamma or beta-gamma' microstructures can exhibit significant room-temperature tensile ductility. In the case of Ni-Al-Cr-based alloys, microstructural development is complicated by the precipitation of alpha-Cr, which can supplant the gamma-phase during ageing of three-phase beta-gamma/gamma' microstructures. An investigation of the stability, during ageing, of cast Ni-Al-Cr-(Co) alloys with microstructures derived from beta-gamma/gamma' is reported. In the as-cast condition, the materials investigated consisted of a dendritic matrix containing L1(0) type martensite and interdendritic gamma/gamma'. Extensive intra- and interdendritic alpha-Cr precipitation was also observed. The stability during ageing of the interdendritic gamma/gamma' microstructure is also considered and transformation of the L1(0) martensite is examined. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Gale, WF (reprint author), AUBURN UNIV,MAT RES & EDUC CTR,AUBURN,AL 36849, USA. NR 15 TC 13 Z9 13 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 1 PY 1996 VL 31 IS 7 BP 1681 EP 1688 DI 10.1007/BF00372178 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA UF442 UT WOS:A1996UF44200003 ER PT J AU Patri, S Gurusamy, R Molian, PA Govindaraju, M AF Patri, S Gurusamy, R Molian, PA Govindaraju, M TI Magnetic domain refinement of silicon-steel laminations by laser scribing SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID POWER LOSSES; INDUCTION AB Laser scribing of 3% silicon steel laminations was carried out using three different lasers: a KrF excimer laser, a pulsed Nd:YAG laser and a continuous wave CO2 laser. The processing parameters included the energy fluence at the surface of the workpiece, pulse repetition rate and pulse separation distance (for the pulsed lasers), scan separation distance and scan direction. The samples were tested for hysteresis loss, permeability, coercivity, remanence and saturation induction before and after laser treatment. An overall improvement in the core loss was observed in the laser-scribed samples. The best improvement in core loss was obtained in excimer laser scribing on the rolling direction and CO2 laser scribing in the transverse direction. Three mechanisms were proposed to explain the improvement in energy efficiency characteristics of the silicon-steel samples: magnetic domain refinement, stress relaxation and inhibition of domain-wall movement. Domain refinement, namely the formation of subdomains, results from the shocks induced by the beam. Laser scribing also relieves the stresses that are induced in the material during manufacture. The scribe lines increase the surface resistivity of the material, resulting in reduced eddy current loss. Tensile stresses are created between the laser scribe lines that elongate the domains and serve to refine the domain-wall spacing thus inhibiting the wall movement and reducing core losses. C1 IOWA STATE UNIV,AMES LAB,AMES,IA 50011. RP Patri, S (reprint author), IOWA STATE UNIV,DEPT MECH ENGN,AMES,IA 50011, USA. NR 13 TC 5 Z9 8 U1 0 U2 3 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 1 PY 1996 VL 31 IS 7 BP 1693 EP 1702 DI 10.1007/BF00372180 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA UF442 UT WOS:A1996UF44200005 ER PT J AU Foltz, MF Maienschein, JL Green, LG AF Foltz, MF Maienschein, JL Green, LG TI Particle size control of 1,3,5-triamino-2,4,6-trinitrobenzene by recrystallization from DMSO SO JOURNAL OF MATERIALS SCIENCE LA English DT Article AB Batches of up to 46 g of the insensitive explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) have been recrystallized from DMSO in an effort to prepare larger particle-size material for recycling previously-used TATB and also for use in special formulations. The first part of the study investigated the conditions required to shift the particle-size distribution maximum from similar to 50-70 mu m to several hundred micrometres in diameter. Distributions peaking at similar to 200-246 mu m were successfully produced by varying the cooldown rate and degree of agitation during cooling. The second part of the study emphasized regeneration of the standard similar to 50-70 mu m distribution from submicron size (''ultrafine'' TATB) particles. The distributions peaking at similar to 76-88 mu m, similar to 27-31 mu m, and similar to 15-17 mu m, successfully bracketed the target particle sizes, were grown by changing the degree of solution saturation. The choice of saturation temperature for the TATB/DMSO solution was based on earlier small-scale recrystallization and solubility work. RP Foltz, MF (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-282,LIVERMORE,CA 94550, USA. NR 11 TC 10 Z9 13 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 1 PY 1996 VL 31 IS 7 BP 1741 EP 1750 DI 10.1007/BF00372187 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA UF442 UT WOS:A1996UF44200012 ER PT J AU Foltz, MF Ornellas, DL Pagoria, PF Mitchell, AR AF Foltz, MF Ornellas, DL Pagoria, PF Mitchell, AR TI Recrystallization and solubility of 1,3,5-triamino-2,4,6-trinitrobenzene in dimethyl sulfoxide SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID BENZENEHEXAMINE AB The insensitive explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) has been recrystallized from dimethylsulfoxide (DMSO) with particle sizes ranging up to 2 mm diameter. Crystal growth was controlled by varying the heating and cooling rates and the solution agitation speed. The role of additives and ''green'' u.v. radiation-induced impurity in affecting crystal morphology, size, and colour was also studied. To provide the thermal concentration data needed for the crystallization study, the solubility curve of TATB in DMSO was determined gravimetrically. The solubility data spans the range of 0.47 +/- 0.23 g l(-1) at 21.2 degrees C to 6.80 +/- 1.13 g l(-1) at 145.5 degrees C. RP Foltz, MF (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-282,LIVERMORE,CA 94550, USA. NR 24 TC 18 Z9 21 U1 1 U2 4 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD APR 1 PY 1996 VL 31 IS 7 BP 1893 EP 1901 DI 10.1007/BF00372205 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA UF442 UT WOS:A1996UF44200030 ER PT J AU Mulford, RN Kim, KC AF Mulford, RN Kim, KC TI Measurement and analysis of the Fourier transform spectra of the nu(3) fundamental and nu(1)+nu(3) combination of NpF6 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID UF6; NU-1+NU-3; MOLECULES; BANDS AB The high resolution spectrum of NpF6 complements existing work on UF6 and PuF6. Unlike these molecules, NpF6 has an unpaired spin, requiring a different mathematical formalism for analysis of the data than was used for the closed shell molecule UF6. Like UF6, NpF6 exhibits rotational manifold structure. Scalar constants for the molecule and some examples of manifolds are presented here, and available constants are compared with those of UF6 and PuF6. (C) 1996 Academic Press, Inc. RP Mulford, RN (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 1996 VL 176 IS 2 BP 369 EP 374 DI 10.1006/jmsp.1996.0098 PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA UK885 UT WOS:A1996UK88500017 ER PT J AU Cedeno, W Vemuri, VR AF Cedeno, W Vemuri, VR TI Genetic algorithms in aquifer management SO JOURNAL OF NETWORK AND COMPUTER APPLICATIONS LA English DT Article AB A new genetic algorithm based on multi-niche crowding is capable of efficiently locating all the peaks of a multi-modal function. By associating these peaks with the utility accrued from different sets of decision variables it is possible to extend the use of genetic algorithms to multi-criteria decision making problems. This concept is applied to address the problems arising in the context of remediation of a contaminated aquifer. The multi-niche crowding genetic algorithm is used to decide the optimal location of pumping wells. The aquifer dynamics are simulated by repeatedly solving the partial differential equations describing the flow of water using SUTRA code. Output of this simulation constitutes the input to the genetic algorithm. (C) 1996 Academic Press Limited C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616. NR 22 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 1084-8045 J9 J NETW COMPUT APPL JI J. Netw. Comput. Appl. PD APR PY 1996 VL 19 IS 2 BP 171 EP 187 DI 10.1006/jnca.1996.0013 PG 17 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA UC147 UT WOS:A1996UC14700006 ER PT J AU Lewis, MB Coghlan, WA AF Lewis, MB Coghlan, WA TI Ion-track reaction-rate model for hydrogen production from polymers SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID HEAVY-PARTICLE TRACKS; RADIATION-CHEMISTRY; SURFACE-PROPERTIES; G-VALUES; BEAM; POLYIMIDE AB A theoretical model has been constructed to calculate the early time evolution of hydrogen radicals that form molecular hydrogen in a single track during the ion irradiation of polymers. The calculated G(H-2)-values (number of H-2 molecules formed per 100 eV of absorbed energy) were compared to those recently measured during various ion irradiations of polyethylene (PE), polystyrene (PS), and polycarbonate (PC). In this model the LET (Linear Energy Transfer) of the energetic ion was distributed into two regions: (a) a Gaussian track-core of high energy-density which is caused primarily by atomic excitation, and (b) a long range, low energy-density distribution caused by electron scattering. Following the energy absorption, the interaction of a time dependent distribution of free hydrogen radicals, H-., originating within the initial track begins. This process is described by a set of chemical rate equations. The effect of radical diffusion out of the original track is also included. Using H-. diffusion rates based upon an extrapolation of known values for H-2 and He in polymers, the hydrogen ion reaction rates were estimated. The effective C-H bond (or radical pair) energy was determined to be approximately 10 eV, but varied somewhat with polymer and ion species. The model calculates the residual carbon density profile along the ion track. The implications of this profile for other properties of irradiated polymers are also discussed. C1 GRAND CANYON UNIV,PHOENIX,AZ 85017. RP Lewis, MB (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 37 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 1996 VL 228 IS 3 BP 302 EP 317 DI 10.1016/0022-3115(95)00244-8 PG 16 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA UF559 UT WOS:A1996UF55900005 ER PT J AU Nishino, Y Krauss, AR Lin, YP Gruen, DM AF Nishino, Y Krauss, AR Lin, YP Gruen, DM TI Initial oxidation of zirconium and Zircaloy-2 with oxygen and water vapor at room temperature SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID SURFACE OXIDATION; PHOTOELECTRON-SPECTROSCOPY; ELECTRON; XPS; ZR; ADSORPTION; ZR(0001); ALLOYS; AES AB The initial oxidation of zirconium and Zircaloy-2 with oxygen and water vapor has been investigated at room temperature with Auger electron and X-ray photoelectron spectroscopies. Three suboxides of Zr2O, ZrO and Zr2O3 accompanied by the oxidde of ZrO2 are formed on surfaces in both oxygen and water vapor atmospheres. Formation of ZrO2 starts at about 0.2-0.4 L (1 L = 10(-6) Torr s) oxygen exposure. The oxidation rate of zirconium with oxygen is slightly larger than that of Zircaloy-2. In the case of low pressure water vapor exposure (< 10 L), the amounts of suboxides on the zirconium are larger than on the Zircaloy-2, since dissociation of H2O molecules proceeds more easily on the former. The ZrO2 starts to form after a 1.0 L water vapor exposure, and its formation rate in water vapor ambience is much smaller than that in oxygen. An average composition of ZrO1.50-1.53 and film thickness of 2.3 nm are obtained for surfaces exposed to 30 L oxygen, and a 1.3 nm thick film with composition 2rO(1.06) is obtained for 30 L of water vapor exposure. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP Nishino, Y (reprint author), HITACHI LTD,POWER & IND SYST,DIV RES & DEV,HITACHI,IBARAKI 31912,JAPAN. NR 24 TC 54 Z9 54 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD APR PY 1996 VL 228 IS 3 BP 346 EP 353 PG 8 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA UF559 UT WOS:A1996UF55900009 ER PT J AU Volkow, ND Ding, YS Fowler, JS Wang, GJ Logan, J Gatley, SJ Hitzemann, R Smith, G Fields, SD Gur, R AF Volkow, ND Ding, YS Fowler, JS Wang, GJ Logan, J Gatley, SJ Hitzemann, R Smith, G Fields, SD Gur, R TI Dopamine transporters decrease with age SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE PET; dopamine transporters; degeneration ID POSITRON EMISSION TOMOGRAPHY; PARKINSONS-DISEASE; SUBSTANTIA-NIGRA; HUMAN-BRAIN; C-11 RACLOPRIDE; BINDING-SITES; RECEPTORS; INVIVO; NEUROTRANSMITTERS; PREVALENCE AB Postmortem studies have documented degeneration of dopamine cells with age, but the changes that occur in healthy aging individuals is less clear. The purpose of this study was to evaluate the extent to which age-induced changes in dopamine transporters occur in subjects with no evidence of motor impairment. Methods: We evaluated 23 right-handed healthy volunteers (age range 20-74 yr) using PET and [C-11]d-threo-methylphenidate. The ratio of the distribution volume for [C-11]d-threo-methylphenidate in striatum to that in cerebellum was used as model parameter for dopamine transporter availability (Bmax/Kd + 1). Results: Dopamine transporter availability was significantly lower in subjects >40 yr of age than in those <40 yr. Estimates of dopamine transporter availability showed a significant negative correlation with age both for the putamen (r = -0.72, p < 0.0001) and the caudate (r = -0.74, p < 0.0001). Dopamine transporter availability was higher in the left than in the right putamen but did not differ between the left and right caudate. Conclusion: This study documents a 6.6% decrease per decade of life in striatal dopamine transporters of healthy volunteers. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. SUNY STONY BROOK,DEPT PSYCHIAT,STONY BROOK,NY 11794. SUNY STONY BROOK,DEPT MED,DIV GERIATR,STONY BROOK,NY 11794. NYU,DEPT PSYCHIAT,NEW YORK,NY 10016. UNIV PENN,DEPT PSYCHIAT,PHILADELPHIA,PA 19104. RP Volkow, ND (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. FU NIDA NIH HHS [5RO1-DA06891] NR 44 TC 177 Z9 181 U1 0 U2 3 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 22090-5316 SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD APR PY 1996 VL 37 IS 4 BP 554 EP 559 PG 6 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UD634 UT WOS:A1996UD63400005 PM 8691238 ER PT J AU Guidry, MW Feng, DH Pan, XW Wu, CL AF Guidry, MW Feng, DH Pan, XW Wu, CL TI Solution of the nuclear shell model by symmetry-dictated truncation SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Review ID FERMION DYNAMICAL SYMMETRY; INTERACTING BOSON APPROXIMATION; GROUND-STATE PROPERTIES; RARE-EARTH NUCLEI; HEAVY-NUCLEI; PT-196; ISOTOPES; MASSES; IDENTIFICATION; COLLECTIVITY AB The dynamical symmetries of the fermion dynamical symmetry model are used as a principle of truncation for the spherical shell model. Utilizing the usual principle of energy-dictated truncation to select a valence space, and symmetry-dictated truncation to select a collective subspace of that valence space, we are able to reduce the full shell model space to one of manageable dimensions with modem supercomputers, even for the heaviest nuclei. The resulting shell model then consists of diagonalizing an effective Hamiltonian within the restricted subspace. This theory is not confined to any symmetry limits, and represents a full solution of the original shell model if the appropriate effective interaction of the truncated space can be determined. As a first step in constructing that interaction, we present an empirical determination of its matrix elements for the collective subspace with no broken pairs in a representative set of nuclei with 130 less than or equal to A less than or equal to 250. We demonstrate that this effective interaction can be parametrized in terms of a few quantities varying slowly with particle number, and is capable of describing a broad range of low-energy observables for these nuclei. Finally we give a brief discussion of extending these methods to include a single broken collective pair. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. DREXEL UNIV,DEPT PHYS & ATMOSPHER SCI,PHILADELPHIA,PA 19104. CHUNG YUAN CHRISTIAN UNIV,DEPT PHYS,CHUNGLI 32023,TAIWAN. RP Guidry, MW (reprint author), UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996, USA. NR 84 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD APR PY 1996 VL 22 IS 4 BP 425 EP 453 DI 10.1088/0954-3899/22/4/004 PG 29 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UE977 UT WOS:A1996UE97700004 ER PT J AU Larsson, J AF Larsson, J TI A new Hamiltonian formulation for fluids and plasmas .1. The perfect fluid SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID LIE PERTURBATION EQUATIONS; VLASOV-MAXWELL SYSTEM; ACTION PRINCIPLE; VARIATIONAL-PRINCIPLES; HERMITIAN STRUCTURE; WAVE INTERACTIONS; HYDRODYNAMICS; POISSON; ENERGY; FLOWS AB A new formulation of the Hamiltonian structure underlying the perfect fluid equations is presented. Besides time, a parameter epsilon is also used. Correspondingly, there are two interdependent systems of equations expressing time evolution and epsilon evolution respectively. The accessibility equations define the epsilon dynamics and give the variation in the usual Eulerian fluid variables as determined by the generating functions. The time evolutions of both the Eulerian fluid variables and the generating functions are obtained from an action principle. The consistency of the epsilon and the time dynamics is crucial for this formulation, i.e. the accessibility equations must be propagated in time by the Euler-Lagrange equations. The reason for introducing this new formulation is its power in certain applications where the existing Hamiltonian alternatives seem less convenient to use. In particular, it is a promising tool for Hamiltonian perturbation theory. We consider the small-amplitude expansion, and find, very simply and naturally, the Hermitian structure of the linearized ideal fluid equations as well as coupling coefficients for resonant three-wave interaction exhibiting the Manley-Rowe relations. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Larsson, J (reprint author), UMEA UNIV,DEPT PLASMA PHYS,S-90187 UMEA,SWEDEN. NR 51 TC 6 Z9 6 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD APR PY 1996 VL 55 BP 235 EP 259 PN 2 PG 25 WC Physics, Fluids & Plasmas SC Physics GA UM670 UT WOS:A1996UM67000007 ER PT J AU Larsson, J AF Larsson, J TI A new Hamiltonian formulation for fluids and plasmas .2. MHD models SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID LIE PERTURBATION EQUATIONS; PRESSURE ANISOTROPY; HERMITIAN STRUCTURE; ACTION PRINCIPLE; VLASOV EQUATION; INSTABILITY; POISSON; SYSTEM AB The new Hamiltonian formulation of the perfect fluid equations presented in part 1 of this series of papers is generalized to a class of MHD models, including for example ideal MHD and the Chew-Goldberger-Low equations. The mathematical structure is to a great extent unchanged by this generalization, and most results about the small-amplitude expansion of the perfect fluid equations remain obviously valid. For example, we now have a rigorous proof of the Manley-Rowe relations in resonant three-wave interaction, valid for this class of MHD models and for quite general inhomogeneous but stationary background states, including equilibrium flows. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Larsson, J (reprint author), UMEA UNIV,DEPT PLASMA PHYS,S-90187 UMEA,SWEDEN. NR 23 TC 8 Z9 8 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD APR PY 1996 VL 55 BP 261 EP 278 PN 2 PG 18 WC Physics, Fluids & Plasmas SC Physics GA UM670 UT WOS:A1996UM67000008 ER PT J AU Larsson, J AF Larsson, J TI A new Hamiltonian formulation for fluids and plasmas .3. Multifluid electrodynamics SO JOURNAL OF PLASMA PHYSICS LA English DT Article ID LIE PERTURBATION EQUATIONS; GUIDING CENTER THEORIES; VLASOV-MAXWELL SYSTEM; ACTION PRINCIPLE AB The Hamiltonian structure underlying ideal multifluid electrodynamics is formulated in a way that simplifies Hamiltonian perturbation calculations. We consider linear and lowest-order nonlinear theory, and the results in Part 1 of this series of papers are generalized in a satisfactory way. Thus the Hermitian structure of linearized dynamics is derived, and we obtain the coupling coefficients for resonant three-wave interaction in symmetric form, giving the Manley-Rowe relations. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Larsson, J (reprint author), UMEA UNIV,DEPT PLASMA PHYS,S-90187 UMEA,SWEDEN. NR 24 TC 4 Z9 4 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-3778 J9 J PLASMA PHYS JI J. Plasma Phys. PD APR PY 1996 VL 55 BP 279 EP 300 PN 2 PG 22 WC Physics, Fluids & Plasmas SC Physics GA UM670 UT WOS:A1996UM67000009 ER PT J AU Knapp, FF Beets, SMAL AF Knapp, FF Beets, SMAL TI Reactor production and processing of therapeutic radioisotopes for applications in nuclear medicine SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES LA English DT Article; Proceedings Paper CT International Conference on Isotopes CY MAY 07-12, 1995 CL BEIJING, PEOPLES R CHINA SP Amer Nucl Soc, Isotopes & Radiat Div, Brit Nucl Energy Soc, China Natl Nucl Corp, Chinese Chem Soc, European Nucl Soc, German Chem Soc, Nucl Chem Sect, Indian Nucl Soc, Int Isotope Soc, Japan Radioisotope Assoc, Korean Nucl Soc, Natl Nat Sci Fdn China, Nucl Soc Russia ID GENERATORS AB In this paper the reactor production of a variety of therapeutic radionuclides of current clinical interest are discussed. Examples include radioisotopes produced by single neutron capture and those which are available from beta(-)/decay of reactor-produced parent radioisotopes. Two examples of generator parents produced by double neutron capture of targets are also discussed. One key example in this category is W-188, produced from irradiation of enriched W-186. The production of W-188 in the ORNL High Flux Isotope Reactor and the fabrication and performance of the first production level large-scale clinical prototype W-188/Re-188 generators are also described. RP Knapp, FF (reprint author), OAK RIDGE NATL LAB,HLTH SCI RES DIV,NUCL MED GRP,OAK RIDGE,TN 37831, USA. NR 19 TC 8 Z9 8 U1 0 U2 0 PU AKADEMIAI KIADO PI BUDAPEST PA PO BOX 245, H-1519 BUDAPEST, HUNGARY SN 0236-5731 J9 J RADIOAN NUCL CH AR JI J. Radioanal. Nucl. Chem.-Artic. PD APR PY 1996 VL 205 IS 1 BP 93 EP 100 PG 8 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA VD122 UT WOS:A1996VD12200013 ER PT J AU Beals, DM AF Beals, DM TI Determination of technetium-99 in aqueous samples by isotope dilution inductively coupled plasma-mass spectrometry SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES LA English DT Article ID TC-99 AB An isotope dilution/inductively coupled plasma mass spectrometric method (ID/JCP-MS) for measuring the concentration of technetium-99 in aqueous samples was developed at the Savannah River Technology Center (SRTC). The procedure is faster than radiometric tecniques, is less subject to interferences, and has equal or better detection limits. It is currently being used to measure the concentration of Tc-99 in, samples of Savannah River water collected in the vicinity of the Savannah River Site. In this method one liter samples of water are spiked with Tc-97, After equilibration, the technetium is extracted from the sample with a chromatographic resin. Interfering elements, molybdenum and ruthenium, are either not retained by the resin or are washed off with dilute nitric acid. The technetium is then eluted with more concentrated nitric acid, and the Tc-99/Tc-97 ratio in the eluant is measured with an ICP-MS. The Tc-99 concentration in the original sample is calculated from the Tc-99/Tc-97,tio, The chemical recovery of the extraction procedure is greater than 90%. The detection limit of the instrument, taken as three times the background counts at m/z = 99, is 0.6 part per trillion (ppt). The detection limit of the procedure, taken as three times the standard deviation of several reagent blank analyses, is 0.33 pCi/l. RP Beals, DM (reprint author), WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER SITE,AIKEN,SC, USA. NR 11 TC 29 Z9 29 U1 0 U2 1 PU AKADEMIAI KIADO PI BUDAPEST PA PO BOX 245, H-1519 BUDAPEST, HUNGARY SN 0236-5731 J9 J RADIOAN NUCL CH AR JI J. Radioanal. Nucl. Chem.-Artic. PD APR PY 1996 VL 204 IS 2 BP 253 EP 263 DI 10.1007/BF02060314 PG 11 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA UX307 UT WOS:A1996UX30700005 ER PT J AU Zavalij, P Guo, JD Whittingham, MS Jacobson, RA Pecharsky, V Bucher, CK Hwu, SJ AF Zavalij, P Guo, JD Whittingham, MS Jacobson, RA Pecharsky, V Bucher, CK Hwu, SJ TI Keggin cluster formation by hydrothermal reaction of tungsten trioxide with methyl substituted ammonium: The crystal structure of two novel compounds, [NH2(CH3)(2)]6H2W12O40 center dot similar to 4H(2)O and [N(CH3)(4)]6H2W12O40 center dot 2H(2)O SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID PYROCHLORE AB Tungsten(VI) oxides can be formed by mild hydrothermal reactions, with the exact crystalline structure being determined by the cations in solution. The impact on the reaction between tungstic acid and ammonium ions as the hydrogen atoms are systematically substituted by methyl groups is investigated. Ammonium and methylammonium (MA) cations form the pyrochlore structure type (NH4)(x)WO3+x/2. nH(2)O (A) and (MA)(x)WO3+x/2. nH(2)O (B). Ammonium may also form the hexagonal bronze tunnel structure. Using dimethylammonium (DMA), trimethylammonium (TrMA), and tetramethylammonium (TMA) leads to the formation of well crystallized Keggin structures: DMA(6)[H2W12O40]. nH(2)O (C), DMA(6)[H2W12O40]. similar to 4H(2)O (D), TrMA(6)[H2W12O40] (E), TrMA(6)[H2W12O40].similar to 2H(2)O (F), TMA(6)[H2W12O40]. 2H(2)O (G), and in some cases hexagonal tungsten bronzes. Characterization was done using powder and single crystal X-ray analysis, as well as IR and TGA methods. The pyrochlore structures have been refined by the Rietveld method. The powder patterns were indexed to the orthorhombic system (space group Pnma, a = 21.886(4), b = 21.469(4), c = 13.232(3) Angstrom) for E and monoclinic system (P2(1)/n, a = 19.273(4), b = 12.017(2), c = 12.253(2) Angstrom, beta = 90.70(1)degrees) in the case of F. The crystal structures of D and G were determined by single crystal X-ray analysis. Blue crystals of D are orthorhombic, space group Pnma, a = 22.446(3), b = 19.810(3), c = 12.854(2) Angstrom, V-cell = 5716 Angstrom(3), Z = 4, d(clc) = 3.72 g/cm(3) (MoK alpha radiation, 2 theta(max.) = 55 degrees, R = 0.077 for 2076 reflections). Dark blue crystals of G are orthorhombic, space group Pnma, a = 21.90(1), b = 21.507(7), c = 13.27(1) Angstrom, V-cell = 6250 Angstrom(3), Z = 4, d(clc) 3.54 g/cm(3) (MoK alpha radiation, 2 theta(max.) = 55 degrees, R = 0.052 for 4488 reflections). Both structures consist of a hexagonal close packed arrangement of the almost spherical Keggin anions [H2W12O40](-6). They are not isostructural because of a different orientation of the tungsten clusters. (C) 1996 Academic Press, Inc. C1 SUNY BINGHAMTON,MAT RES CTR,BINGHAMTON,NY 13902. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RICE UNIV,DEPT CHEM,HOUSTON,TX 77251. CLEMSON UNIV,DEPT CHEM,CLEMSON,SC 29634. RP Zavalij, P (reprint author), SUNY BINGHAMTON,DEPT CHEM,BINGHAMTON,NY 13902, USA. RI Zavalij, Peter/H-3817-2012 OI Zavalij, Peter/0000-0001-5762-3469 NR 23 TC 37 Z9 38 U1 3 U2 7 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1996 VL 123 IS 1 BP 83 EP 92 DI 10.1006/jssc.1996.0155 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA UJ119 UT WOS:A1996UJ11900011 ER PT J AU Vogt, T Buttrey, DJ AF Vogt, T Buttrey, DJ TI Temperature dependent structural behavior of Sr2RhO4 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Letter AB Variations in the structure of Sr2RhO4 as a function of temperature have been investigated using high-resolution neutron powder diffraction, The K2NiF4-type structure possesses microdomains distinguished by clockwise versus anticlockwise rotation of the RhO6 octahedra, These domains have nonequivalent sizes which vary with temperature. (C) 1996 Academic Press, Inc. C1 UNIV DELAWARE, DEPT CHEM ENGN, NEWARK, DE 19716 USA. RP Vogt, T (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RI Vogt, Thomas /A-1562-2011 OI Vogt, Thomas /0000-0002-4731-2787 NR 10 TC 20 Z9 20 U1 1 U2 14 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD APR PY 1996 VL 123 IS 1 BP 186 EP 189 DI 10.1006/jssc.1996.0167 PG 4 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA UJ119 UT WOS:A1996UJ11900023 ER PT J AU Cadle, SH Bailey, BK Belian, TC Carlock, M Gorse, RA Haskew, H Knapp, KT Lawson, DR AF Cadle, SH Bailey, BK Belian, TC Carlock, M Gorse, RA Haskew, H Knapp, KT Lawson, DR TI Real world vehicle emissions: A summary of the fifth coordinating research council on-road vehicle emissions workshop SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Editorial Material C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO. COORDINATING RES COUNCIL,ATLANTA,GA. CALIF AIR RESOURCES BOARD,EL MONTE,CA. FORD MOTOR CO,DEARBORN,MI 48121. GM PROVING GROUND,MILFORD,MI. US EPA,RES TRIANGLE PK,NC 27711. COLORADO STATE UNIV,FT COLLINS,CO 80523. RP Cadle, SH (reprint author), GM CORP,CTR RES & DEV,WARREN,MI, USA. NR 0 TC 4 Z9 4 U1 0 U2 1 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA PO BOX 2861, PITTSBURGH, PA 15230 SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD APR PY 1996 VL 46 IS 4 BP 355 EP 369 PG 15 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UD654 UT WOS:A1996UD65400011 ER PT J AU Bae, YW Lee, WY Yust, CS Blau, PJ Besmann, TM AF Bae, YW Lee, WY Yust, CS Blau, PJ Besmann, TM TI Synthesis and friction behavior of chemically vapor deposited composite coatings containing discrete TiN and MoS2 phases SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID TITANIUM NITRIDE; FILMS AB Composite coatings containing discrete crystalline phases of TIN and MoS2 were deposited on Si, graphite, and Ti-6A1-4V alloy substrates by simultaneous chemical vapor deposition, MoF6 and H2S were utilized as the precursors for MoS2 formation, while Ti((CH3)(2)N)(4) and NH3 were used for TIN deposition, The composition and microstructure of the coatings were investigated by X-ray diffraction, Auger electron spectroscopy, and transmission electron microscopy, The molar ratios of TIN and MoS2 in the composite microstructure could be controlled by adjusting the MoF6 concentration in the reagent mixture, Encouraging friction and wear characteristics against silicon nitride were obtained for a composite coating which was rich in MoS2 at the coating surface, with TIN as the major phase near the substrate interface, Friction coefficients at room temperature in air were typically in the range of 0.07 to 0.3, The friction coefficients remained comparable at 573 K, but increased to 0.7 to 1.0 at 673 K, A friction coefficient value of similar to 0.3 was, however, obtained from a composite coating tested at 973 K. RP Bae, YW (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 25 TC 11 Z9 13 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD APR PY 1996 VL 79 IS 4 BP 819 EP 824 DI 10.1111/j.1151-2916.1996.tb08511.x PG 6 WC Materials Science, Ceramics SC Materials Science GA UG959 UT WOS:A1996UG95900001 ER PT J AU Meyer, MK Akinc, M AF Meyer, MK Akinc, M TI Oxidation behavior of boron-modified Mo5Si3 at 800 degrees-1300 degrees C SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID LOW-TEMPERATURE OXIDATION; MOLYBDENUM DISILICIDE; SLIP SYSTEMS; MOSI2; HARDNESS; PEST AB Mo5Si3 shows promise as a high-temperature creep-resistant material. The high-temperature oxidation resistance of Mo5Si3 has been found to be poor, however, limiting its use in oxidizing atmospheres. Undoped Mo5Si3 exhibits pest oxidation at 800 degrees C. Mass loss occurs in the temperature range 900 degrees-1200 degrees C due to volatilization of molybdenum oxide, indicating that the silica scale that forms does not provide a passivating layer. The addition of boron results in protective scale formation and parabolic oxidation kinetics in the temperature range of 1050 degrees-1300 degrees C. The oxidation rate of Mo5Si3 was decreased by 5 orders of magnitude at 1200 degrees C by doping with less than 2 wt% boron. Boron doping eliminates catastrophic pest oxidation at 800 degrees C. The mechanism for improved oxidation resistance of boron-doped Mo5Si3 is viscous sintering of the scale to close pores that form during the initial transient oxidation period, due to volatilization of molybdenum oxide. C1 IOWA STATE UNIV,DEPT MAT SCI & ENGN,AMES,IA 50011. RP Meyer, MK (reprint author), IOWA STATE UNIV,AMES LAB,AMES,IA 50011, USA. OI Meyer, Mitchell/0000-0002-1980-7862 NR 39 TC 143 Z9 148 U1 3 U2 15 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD APR PY 1996 VL 79 IS 4 BP 938 EP 944 DI 10.1111/j.1151-2916.1996.tb08528.x PG 7 WC Materials Science, Ceramics SC Materials Science GA UG959 UT WOS:A1996UG95900018 ER PT J AU Blumenthal, WR Phillips, DS AF Blumenthal, WR Phillips, DS TI High-temperature deformation of single-crystal yttrium-aluminum garnet (YAG) SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CREEP AB Single crystals of Y3Al5O12 (YAG) were deformed in air along the [135] direction at 1635 degrees and 1785 degrees C using constant strain rate compression, The primary creep region, characterized by ''strain softening,'' persists to at least 4% plastic strain before steady-state behavior is achieved. Creep rates, stress exponents, and activation energies were compared to literature results and suggest the operation of multiple mechanisms over the range of conditions studied, Slip trace analysis confirmed that {110}[(1) over bar 11] was the primary slip system. Slip on both highly stressed (211) and ''anomalous'' (1(1) over bar2$) planes was also observed, Dislocation structures mere analyzed by transmission electron microscopy and consisted of networks and coarse loops. These results are discussed in terms of asymmetric slip geometry classically observed in body-centered cubic (BCC) metals. RP Blumenthal, WR (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 11 TC 32 Z9 32 U1 0 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD APR PY 1996 VL 79 IS 4 BP 1047 EP 1052 DI 10.1111/j.1151-2916.1996.tb08546.x PG 6 WC Materials Science, Ceramics SC Materials Science GA UG959 UT WOS:A1996UG95900036 ER PT J AU Paxton, B Newman, J AF Paxton, B Newman, J TI Variable diffusivity in intercalation materials - A theoretical approach SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB A theoretical approach for estimating a best constant coefficient to use in an electrode model is presented for the case where experimental data exist on the diffusion coefficient as a function of the state of charge of an intercalation material. this method uses a model of diffusion in a single particle as its basis. From examining the surface concentration vs. average concentration curve for diffusion in a single particle, we can determine a diffusion coefficient that is a function of the dimensionless flux rate of material into the particle. This diffusion coefficient function can then be used in a model of a porous electrode. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. RP Paxton, B (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720, USA. RI Newman, John/B-8650-2008 OI Newman, John/0000-0002-9267-4525 NR 12 TC 28 Z9 28 U1 0 U2 7 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD APR PY 1996 VL 143 IS 4 BP 1287 EP 1292 DI 10.1149/1.1836631 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA UF815 UT WOS:A1996UF81500029 ER PT J AU Benton, JL Stolk, PA Eaglesham, DJ Jacobson, DC Cheng, JY Poate, JM Myers, SM Haynes, TE AF Benton, JL Stolk, PA Eaglesham, DJ Jacobson, DC Cheng, JY Poate, JM Myers, SM Haynes, TE TI The mechanisms of iron gettering in silicon by boron ion-implantation SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB Boron implantation into silicon offers a unique system for studying the gettering mechanisms of Fe. The effectiveness of the gettering increases as the high-energy B ion implantation dose changes from 4E12 to 4E14 cm(-2), decreasing the Fe concentration in the near surface region to below the deep level transient spectroscopy detection limit of 1E10 cm(-3) Fermi level-induced Fe solubility enhancement and Fermi level-controlled Fe-B pairing combine to produce a relative partitioning for Fe as high as 10(6), for temperatures less than 400 degrees C, in high B-doped implanted regions adjacent to regions of low B bulk doping. Comparison studies show that in the time-temperature regimes typical of Si device fabrication, B gettering is more effective than gettering produced by Si implantation damage and more effective than trapping by a neutral impurity such as C. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Benton, JL (reprint author), AT&T BELL LABS,600 MT AVE,MURRAY HILL,NJ 07974, USA. RI Haynes, Tony/P-8932-2015 OI Haynes, Tony/0000-0003-2871-4745 NR 13 TC 16 Z9 16 U1 0 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD APR PY 1996 VL 143 IS 4 BP 1406 EP 1409 DI 10.1149/1.1836651 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA UF815 UT WOS:A1996UF81500049 ER PT J AU Romero, LA Dickey, FM AF Romero, LA Dickey, FM TI Lossless laser beam shaping SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID UNIFORM BEAM AB The Fresnel approximation is used in the design of a lens that turns a beam with one intensity distribution into a beam with a different distribution at the focal plane of a Fourier transform lens. In general, this cannot be done exactly, so one must be satisfied with approximate solutions to this problem. It is shown that the difficulty of this problem depends on a parameter beta that is a dimensionless measure of how well the geometrical optics approximation holds. An analytical method is given for determining the lens when beta is large. The sensitivity of this solution to various imperfections in the system alignment is also analyzed. (C) 1996 Optical Society of America RP Romero, LA (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 6 TC 106 Z9 108 U1 1 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD APR PY 1996 VL 13 IS 4 BP 751 EP 760 DI 10.1364/JOSAA.13.000751 PG 10 WC Optics SC Optics GA UB623 UT WOS:A1996UB62300009 ER PT J AU Stroud, PD AF Stroud, PD TI Anisoplanatism in adaptive optics compensation of a focused beam with use of distributed beacons SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID LASER GUIDE STARS; PERFORMANCE; TURBULENCE AB In systems that achieve laser beam propagation through atmospheric turbulence by phase compensation with adaptive optics, the performance depends on the beacon's spatial distribution. A formulation is obtained to calculate the anisoplanatic Strehl ratio of a phase-compensated, focused beam for any beacon distribution and turbulence profile. Analytic results are obtained for several beacon geometries corresponding to practical systems in the large aperture limit. The effects of finite aperture are evaluated for two representative beacon geometries with use of both uniform and highly localized turbulence profiles. The spread of the beacon distribution is found to be much less deleterious than the offset of the beacon centroid from the aimpoint. The anisoplanatic effect is qualitatively different in systems characterized by a focused beam geometry and in systems where the collimated beam geometry applies. (C) 1996 Optical Society of America RP Stroud, PD (reprint author), LOS ALAMOS NATL LAB,POB 1663,MS-F607,LOS ALAMOS,NM 87544, USA. NR 23 TC 6 Z9 8 U1 6 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD APR PY 1996 VL 13 IS 4 BP 868 EP 874 DI 10.1364/JOSAA.13.000868 PG 7 WC Optics SC Optics GA UB623 UT WOS:A1996UB62300022 ER PT J AU Ditmire, T Rubenchik, AM Eimerl, D Perry, MD AF Ditmire, T Rubenchik, AM Eimerl, D Perry, MD TI Effects of cubic nonlinearity on frequency doubling of high-power laser pulses SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID REFRACTIVE-INDEX; 2ND-HARMONIC GENERATION; OPTICAL-CRYSTALS; 2ND-ORDER AB The effects of the phase mismatch due to cubic nonlinearity in the equations for second-harmonic generation are investigated. We show that the phase mismatch induced by the nonlinear refractive index of a doubling crystal can dramatically reduce the conversion efficiency of high-peak-power laser pulses. Simple, analytic expressions are derived for the conversion efficiency of cw radiation and for the estimation of the dispersion in the nonlinear refractive index of the doubling crystal, which is quite important in the determination of the magnitude of the nonlinear effects on maximum conversion. The consequences that these nonlinearities have on the frequency doubling of ultrashort (less than or equal to 100 fs) pulses, including the additional effects of group-velocity walk-off between the pulses, are then numerically calculated. (C) 1996 Optical Society of America RP Ditmire, T (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-443,LIVERMORE,CA 94550, USA. NR 18 TC 63 Z9 64 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1996 VL 13 IS 4 BP 649 EP 655 DI 10.1364/JOSAB.13.000649 PG 7 WC Optics SC Optics GA UE687 UT WOS:A1996UE68700002 ER PT J AU Li, YL Pretzler, G Fill, EE Nilsen, J AF Li, YL Pretzler, G Fill, EE Nilsen, J TI Temporally and spatially resolved investigation of the J=0-1 and J=2-1, 3p-3s laser emissions in neonlike germanium SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID NE-LIKE GERMANIUM; 23.6 NM AB We report a time- and space-resolved investigation of the J = 0-1 and J = 2-1 lasers in neonlike germanium at 19.6, 23.2, and 23.6 nm. Germanium slabs were irradiated by the Asterix TV iodine laser at an intensity of approximately 2.0 x 10(13) W cm(-2) without and with a prepulse, which was 5.23 ns before the main pulse. The position of the lasing region was measured as a function of the prepulse intensity. It was found that lasing on the J = 0-1 transition at 19.6 nm occurs earlier in time and closer to the target surface than on the two J = 2-1 transisitions at 23.2 and 23.6 nm. The position for the 23.6-nm laser is the farthest from the target surface. A larger prepulse shifted all lasers farther from the target surface. Numerical simulations showed good qualitative agreement with experimental results when a prepulse was applied. For the case without a prepulse, calculations indicated the importance of beam refraction in modifying the effective gain of the soft-x-ray laser beam. (C) 1996 Optical Society of America C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Li, YL (reprint author), MAX PLANCK INST QUANTUM OPT,D-85748 GARCHING,GERMANY. NR 32 TC 10 Z9 12 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1996 VL 13 IS 4 BP 742 EP 750 DI 10.1364/JOSAB.13.000742 PG 9 WC Optics SC Optics GA UE687 UT WOS:A1996UE68700014 ER PT J AU Hogan, RE Blackwell, BF Cochran, RJ AF Hogan, RE Blackwell, BF Cochran, RJ TI Application of moving grid control volume finite element method to ablation problems SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB This article presents the solution of two-dimensional axisymmetric ablation problems with unstructured grids. The energy equation is formulated and solved using the control volume finite element method. The exterior shape of the ablating body is determined from a surface energy balance with the interior mesh displaced in response to the surface ablation as if the body was a linear elastic solid. Boundary condition matrices are formulated for both heat of ablation and generalized thermochemical ablation boundary conditions. Computed recession rates are compared to an analytical solution to demonstrate the accuracy and convergence of this approach. Additionally, the practical application of this approach to the ablation of a re-entry vehicle nose tip is presented. RP Hogan, RE (reprint author), SANDIA NATL LABS,THERMAL SCI DEPT,TECH STAFF,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 17 TC 15 Z9 18 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 1996 VL 10 IS 2 BP 312 EP 319 DI 10.2514/3.789 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA UE790 UT WOS:A1996UE79000016 ER PT J AU Lovich, JE Gotte, SW Ernst, CH Harshbarger, JC Laemmerzahl, AF Gibbons, JW AF Lovich, JE Gotte, SW Ernst, CH Harshbarger, JC Laemmerzahl, AF Gibbons, JW TI Prevalence and histopathology of shell disease in turtles from Lake Blackshear, Georgia SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE turtle; Trachemys scripta; Pseudemys concinna; shell disease; osteitis AB Turtles in Lake Blackshear, Crisp County, Georgia (USA) were evaluated for shell disease during intensive trapping efforts on 8 and 9 May 1990. The disease was most prevalent in Pseudemys concinna (74%) and Trachemys scripta (35%). The degree of necrosis on the carapace was significantly positively correlated with the degree of necrosis on the plastron in T. scripta (r(s) = 0.50), but not in P. concinna (r(s) = 0.06). Female T. scripta with lesions were significantly larger than females without lesions. Lesions were not detected on six other species of turtles. Some areas contained multinucleate osteoclasts that were destroying bone. No tumors were detected in soft tissue samples. C1 NATL MUSEUM NAT HIST,NATL BIOL SERV,BIOL SURVEY PROJECT,WASHINGTON,DC 20560. GEORGE MASON UNIV,DEPT BIOL,FAIRFAX,VA 22030. GEORGE WASHINGTON UNIV,MED CTR,REGISTRY TUMORS LOWER ANIM,DEPT PATHOL,WASHINGTON,DC 20037. SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. OI Lovich, Jeffrey/0000-0002-7789-2831 FU NCI NIH HHS [N0I-CP-15641] NR 15 TC 10 Z9 11 U1 0 U2 2 PU WILDLIFE DISEASE ASSN, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD APR PY 1996 VL 32 IS 2 BP 259 EP 265 PG 7 WC Veterinary Sciences SC Veterinary Sciences GA UF941 UT WOS:A1996UF94100011 PM 8722263 ER PT J AU Eberhardt, LE Eberhardt, LL Tiller, BL Cadwell, LL AF Eberhardt, LE Eberhardt, LL Tiller, BL Cadwell, LL TI Growth of an isolated elk population SO JOURNAL OF WILDLIFE MANAGEMENT LA English DT Article DE Cervus elaphus; Hanford Reservation; elk; population dynamics; population growth; survival ID DYNAMICS AB This paper reports on the growth of an isolated elk (Cervus elaphus nelsoni) population that became established naturally in a large block of shrub-steppe habitat in eastern Washington. Habitat quality in the area was high as was the potential for achieving maximum or near-maximum rates of sustained population growth. Nearly 20 years of trend data on the population yielded an overall rate of increase of 20% per year. A high annual survival (0.98) was calculated. An initially high calf-cow ratio was reduced in later years of the study, but causes could not be determined. The reproductive and survival data indicate a maximum rate of increase of 24% per year, and the data were used to show that a feasible maximum sustainable rate for elk may be as high as 28%. RP Eberhardt, LE (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 6 TC 41 Z9 42 U1 1 U2 8 PU WILDLIFE SOC PI BETHESDA PA 5410 GROSVENOR LANE, BETHESDA, MD 20814-2197 SN 0022-541X J9 J WILDLIFE MANAGE JI J. Wildl. Manage. PD APR PY 1996 VL 60 IS 2 BP 369 EP 373 DI 10.2307/3802237 PG 5 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA UF002 UT WOS:A1996UF00200019 ER PT J AU Osterheld, A Magunov, AI Dyakin, VM Faenov, AY Pikus, TA Skobelev, IY Pisarchik, T Paris, P Wolowski, J Makowski, J Pikus, SA Romanova, VM Shelkovenko, TA AF Osterheld, A Magunov, AI Dyakin, VM Faenov, AY Pikus, TA Skobelev, IY Pisarchik, T Paris, P Wolowski, J Makowski, J Pikus, SA Romanova, VM Shelkovenko, TA TI Precision measurements of the wavelengths of the AlXII 1snp(1)P(1)-1s(2) S-1(0) (n=6-12) lines in the emission spectra of laser and X-pinch plasmas. SO KVANTOVAYA ELEKTRONIKA LA Russian DT Article ID ENERGY-LEVELS; ATOMS AB The emission spectra of a high-temperature recombining laser plasma and of an X-pinch plasma were used in high-precision (+/-0.03-0.05 nm) measurements of the wavelengths of the AlXII lines resulting from the 1snp(1)P(1) - (1)s(2) S-1(0) (n = 6-12) transitions. The lines due to transitions from the 1s11p and 1s12p levels of the He-like AlXII ion were observed for the first time. The experimental results were compared with calculations carried out by several theoretical methods. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. POLISH PLASMA PHYS & LASER MICROSYNTH INST,WARSAW,POLAND. PN LEBEDEV PHYS INST,MOSCOW 117924,RUSSIA. RP Osterheld, A (reprint author), ALL RUSSIAN PHYS TECH & RADIOENGN MEASUREMENTS RE,MENDELEYEVSK,RUSSIA. RI Romanova, Vera/M-6922-2015; Shelkovenko, Tatiana/M-8254-2015 NR 18 TC 1 Z9 1 U1 0 U2 0 PU LEBEDEV PHYSICAL INST KVANTOVAYA ELEKTRONIKA JOURNAL PI MOSCOW GSP-1 PA LENINSKII PROSPEKT 53, 117924 MOSCOW GSP-1, RUSSIA SN 0368-7147 J9 KVANTOVAYA ELEKTRON+ JI Kvantovaya Elektron. PD APR PY 1996 VL 23 IS 4 BP 359 EP 362 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA UK119 UT WOS:A1996UK11900021 ER PT J AU Panozzo, J Panozzo, J Akan, E Libertin, C Woloschak, GE AF Panozzo, J Panozzo, J Akan, E Libertin, C Woloschak, GE TI The effects of cisplatin and methotrexate on the expression of human immunodeficiency virus type 1 long terminal repeat SO LEUKEMIA RESEARCH LA English DT Article DE DNA damaging agents; methotrexate; cisplatin; HIV gene expression; cancer chemotherapeutic drugs ID COLONY-STIMULATING FACTOR; NON-HODGKINS-LYMPHOMA; IONIZING-RADIATION; ADDUCT FORMATION; KAPOSIS-SARCOMA; DNA ADDUCT; CELL-LINE; RHGM-CSF; CHEMOTHERAPY; ACTIVATION AB Previous work by many groups has documented the induction of HIV-LTR (human immunodeficiency virus-long terminal repeat) following exposure of cells or whole animals to ultraviolet (UV) light and other DNA damaging agents. In these experiments we set out to determine whether exposure to the cancer chemotherapeutic agents methotrexate and cisplatin had any effect on the expression of the HIV-LTR. Using HeLa cells stably transfected with a construct in which HIV-LTR drives the expression of the reporter gene chloramphenicol acetyl transferase (CAT), we demonstrated induction of HIV-LTR 24-48 h following exposure to 50 mu M cisplatin. When UV exposure (10 Jm(-2)) was coupled with cisplatin (50 mu M) treatment (which also causes DNA damage), HIV-LTR induction was additive relative to either treatment alone. Methotrexate, which depletes the medium of tetrahydrofolate and does not induce DNA damage, induced HIV-LTR at later (6-7 days) time points than cisplatin or UV treatments. When methotrexate (128 mu M) and UV (10 Jm(-2)) treatments were combined, the agents were synergistic with regard to HIV induction. For both drugs, though, induction was not due to generalized transcriptional activation since both cisplatin and methotrexate induced a repression of total transcription as measured in nuclear run-on assays. C1 ARGONNE NATL LAB,ARGONNE NATL LAB SUMMER RES PROGRAM STUDENTS,ARGONNE,IL 60439. LOYOLA UNIV,MED CTR,DEPT PATHOL,MAYWOOD,IL 60154. LOYOLA UNIV,MED CTR,DEPT MED,MAYWOOD,IL 60154. ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,ARGONNE,IL 60439. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 NR 28 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0145-2126 J9 LEUKEMIA RES JI Leuk. Res. PD APR PY 1996 VL 20 IS 4 BP 309 EP 317 DI 10.1016/0145-2126(95)00066-6 PG 9 WC Oncology; Hematology SC Oncology; Hematology GA UQ210 UT WOS:A1996UQ21000004 PM 8642842 ER PT J AU Burton, H AF Burton, H TI Bucky works: Buckminster Fuller's ideas for today - Baldwin,J SO LIBRARY JOURNAL LA English DT Book Review RP Burton, H (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD APR 1 PY 1996 VL 121 IS 6 BP 109 EP 109 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA UB440 UT WOS:A1996UB44000155 ER PT J AU Doyle, J Hellevuo, K Stubbs, L AF Doyle, J Hellevuo, K Stubbs, L TI The gene encoding adenylyl cyclase VII is located in central mouse Chromosome 8 SO MAMMALIAN GENOME LA English DT Article ID UNCOUPLING PROTEIN; JUN C1 UNIV TENNESSEE,OAK RIDGE GRAD SCH BIOMED SCI,OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV COLORADO,HLTH SCI CTR,DEPT PHARMACOL,DENVER,CO 80262. RP Doyle, J (reprint author), OAK RIDGE NATL LAB,DIV BIOL,POB 2008,OAK RIDGE,TN 37831, USA. OI Stubbs, Lisa/0000-0002-9556-1972 FU NIAAA NIH HHS [AA09014] NR 15 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0938-8990 J9 MAMM GENOME JI Mamm. Genome PD APR PY 1996 VL 7 IS 4 BP 320 EP 321 PG 2 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA UH896 UT WOS:A1996UH89600016 PM 8661708 ER PT J AU Musilova, P Lee, DA Stratil, A Cepica, S Rubes, J Lowe, X Wyrobek, A AF Musilova, P Lee, DA Stratil, A Cepica, S Rubes, J Lowe, X Wyrobek, A TI Assignment of the porcine IKBA gene (I kappa B alpha) encoding a cytoplasmic inhibitor of the NF-kappa B to chromosome 7q15-q21 by FISH SO MAMMALIAN GENOME LA English DT Article ID CELLS C1 ACAD SCI CZECH REPUBL,INST ANIM PHYSIOL & GENET,CR-27721 LIBECHOV,CZECH REPUBLIC. VET RES INST,CR-62132 BRNO,CZECH REPUBLIC. LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94551. RI Stratil, Antonin/G-7194-2014; Cepica, Stanislav/G-7180-2014; Musilova, Petra/B-7380-2011 NR 12 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0938-8990 J9 MAMM GENOME JI Mamm. Genome PD APR PY 1996 VL 7 IS 4 BP 323 EP 324 PG 2 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA UH896 UT WOS:A1996UH89600020 PM 8661710 ER PT J AU Raymo, ME Grant, B Horowitz, M Rau, GH AF Raymo, ME Grant, B Horowitz, M Rau, GH TI Mid-Pliocene warmth: Stronger greenhouse and stronger conveyor SO MARINE MICROPALEONTOLOGY LA English DT Article ID OCEAN-ATMOSPHERE MODEL; MARINE ORGANIC-MATTER; NORTH-ATLANTIC OCEAN; SURFACE SEDIMENTS; ARCTIC-OCEAN; SEA ICE; CO2; DELTA-C-13; CARBON; WATER AB Three million years ago, prior to the onset of northern hemisphere glaciation, global mean temperatures may have been as much as 3.5 degrees C warmer than at present. We present evidence, based on the carbon isotopic composition of marine organic matter, that atmospheric CO2 levels at this time were on average only about 35% higher than the preindustrial value of 280 ppm. We also present carbon isotopic evidence for stronger thermohaline circulation in the Atlantic Ocean during the warmest intervals and propose that the North Atlantic ''conveyor belt'' may act as a positive feedback to global warming by enhancing sea ice retreat and decreasing high latitude albedo. Based on our results, it seems unlikely that the mid Pliocene warm period was a doubled CO2 world. C1 UNIV CALIF SANTA CRUZ,INST MARINE SCI,SANTA CRUZ,CA 95064. LAWRENCE LIVERMORE NATL LAB,GLOBAL CLIMATE RES DIV,LIVERMORE,CA 94551. RP Raymo, ME (reprint author), MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139, USA. NR 82 TC 240 Z9 250 U1 8 U2 38 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-8398 J9 MAR MICROPALEONTOL JI Mar. Micropaleontol. PD APR PY 1996 VL 27 IS 1-4 BP 313 EP 326 DI 10.1016/0377-8398(95)00048-8 PG 14 WC Paleontology SC Paleontology GA UP078 UT WOS:A1996UP07800021 ER PT J AU Zakharov, ND LilientalWeber, Z Filonenko, VP Zibrov, IP Sundberg, M AF Zakharov, ND LilientalWeber, Z Filonenko, VP Zibrov, IP Sundberg, M TI HRTEM studies of two new (Nd,Ca)(x)WO3 bronzes synthesized under high pressure conditions SO MATERIALS RESEARCH BULLETIN LA English DT Article DE oxides; electron microscopy; high pressure; crystal structure; defects ID INTERGROWTH TUNGSTEN BRONZES AB Two new (Nd,Ca)(x)WO3 bronzes have been prepared by solid state reaction at P = 50 kbar and T approximate to 1520 K. The compounds were studied by X-ray powder diffraction and high resolution transmission electron microscopy. One phase was identified to be of hexagonal tungsten bronze type, while the other one was found to have the intergrowth tungsten bronze structure (2)-ITB. Disorder in terms of varying widths of the HTB and WO3 slabs was sometimes observed. HTB tunnel rows terminating in the (2)-ITB structure were also seen. The neodymium and calcium contents in the two phases were confirmed by EDS analysis. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RUSSIAN ACAD SCI,INST HIGH PRESSURE PHYS,TROITSK 142092,RUSSIA. RUSSIAN ACAD SCI,INST CRYSTALLOG,MOSCOW 117333,RUSSIA. UNIV STOCKHOLM,ARRHENIUS LAB,DEPT INORGAN CHEM,S-10691 STOCKHOLM,SWEDEN. RP Zakharov, ND (reprint author), MAX PLANCK INST MIKROSTRUKT PHYS,WEINBERG 2,D-06120 HALLE,GERMANY. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 18 TC 7 Z9 7 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0025-5408 J9 MATER RES BULL JI Mater. Res. Bull. PD APR PY 1996 VL 31 IS 4 BP 373 EP 380 DI 10.1016/0025-5408(96)00018-9 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA UC445 UT WOS:A1996UC44500006 ER PT J AU Horton, JA Herchenroeder, JW Wright, JL Easton, DS AF Horton, JA Herchenroeder, JW Wright, JL Easton, DS TI Fracture toughness of Nd2Fe14B magnets SO MATERIALS TRANSACTIONS JIM LA English DT Article; Proceedings Paper CT International Symposia on Advanced Material and Technology for the 21st-Century - JIM 95 Fall Annual Meeting CY 1995 CL HI SP Japan Inst Met DE magnets; permanent magnets; toughness; mechanical properties ID PERMANENT-MAGNETS; FE; ND AB Nd2Fe14B is currently the best (highest energy product) hard magnet available. Like most magnetic materials, it is rather brittle. The fracture toughness of specimens of commercially available hard magnets were measured using a chevron notch, three-point bend test. Values for Nd2Fe14B magnets ranged from 2.5 to 5.5 MPa root m. In comparison, SmCo5 was measured to have a fracture toughness of 1.9 MPa root m. It appears that this testing technique will allow differences in fracture toughness to be measured between alloys with different compositions and fabricated by different production methods and should be able to track the fracture toughness as improvements are made to a particular alloy. C1 MAGNEQUENCH INT INC,ANDERSON,IN 46013. RP Horton, JA (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. NR 9 TC 14 Z9 17 U1 2 U2 5 PU JAPAN INST METALS PI SENDAI PA AOBA ARAMAKI, SENDAI 980, JAPAN SN 0916-1821 J9 MATER T JIM JI Mater. Trans. JIM PD APR PY 1996 VL 37 IS 4 BP 860 EP 863 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UR123 UT WOS:A1996UR12300047 ER PT J AU Peurrung, AJ AF Peurrung, AJ TI Capillary optics for neutron capture therapy SO MEDICAL PHYSICS LA English DT Article DE neutron capture therapy; neutron optics; thermal neutron beam; Boron Neutron Capture Therapy (BNCT) ID X-RAY; SURFACE-ROUGHNESS; SCATTERING AB The development of capillary neutron optics permits a new technology for neutron capture therapy involving the application of a focused thermal neutron beam at the medically optimal location within the patient. A subthermal neutron beam begins to converge as it travels through a neutron ''lens,'' reaching a narrow focus within a tube that allows it to pass directly to the treatment region. This technique results in a substantially lower dose to untreated parts of the patient and a substantially weaker radiation field in the treatment room generally. Additional advantages include the relative ease of thermal neutron generation and the ability to shield the patient completely and effectively from fast neutrons or gamma rays originating at the neutron source. This work describes the application of capillary optics to neutron capture therapy, along with Monte Carlo calculations of the neutron flux profiles within a patient for an optimized system design. Specific dose profiles for the case of boron neutron capture therapy within the brain are also provided. (C) 1996 American Association of Physicists in Medicine. RP Peurrung, AJ (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 31 TC 6 Z9 6 U1 0 U2 1 PU AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD APR PY 1996 VL 23 IS 4 BP 487 EP 494 DI 10.1118/1.597680 PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UF507 UT WOS:A1996UF50700004 PM 9157259 ER PT J AU Henager, CH Jones, RH Windisch, CF Stackpoole, MM Bordia, R AF Henager, CH Jones, RH Windisch, CF Stackpoole, MM Bordia, R TI Time-dependent, environmentally assisted crack growth in NICALON-fiber-reinforced SiC composites at elevated temperatures SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article; Proceedings Paper CT Symposium on High Temperature Fracture Mechanisms in Advanced Materials, at the 1994 Fall Meeting of TMS CY OCT 02-06, 1994 CL ROSEMONT, IL SP ASM SMD Flow & Fracture Comm ID FRACTURE-RESISTANCE MECHANISM; AL2O3 BEND SPECIMENS; POLYCRYSTALLINE ALUMINA; CERAMICS; BEHAVIOR; TOUGHNESS; INTERFACE; NUCLEATION; EXTENSION; FATIGUE AB Subcritical crack growth measurements were conducted on ceramic matrix composites of beta-SiC matrix reinforced with NICALON fibers (SiC/SiCf); fiber-matrix interphases were of carbon and boron nitride. Velocities of effective elastic cracks were determined as a function of effective applied stress intensity in pure Ar and in Ar plus 2000, 5000, and 20,000 ppm O-2 atmospheres at 1100 degrees C. Over a wide range of applied stress intensities, the V - K-eff diagrams revealed a stage II pattern in which the crack velocity depends only weakly on the applied stress intensity, followed by a stage III, or power-law, pattern at higher stress intensity. Oxygen increased the crack velocity in stage II and shifted the stage II to III transition to the left. A two-dimensional (2-D) micromechanics approach, developed to model the time dependence of observed crack-bridging events, rationalized the measured effective crack velocities, their time dependence, the stage II to III transition, and the effect of oxygen in terms of the load relaxation of crack-bridging fibers. C1 UNIV WASHINGTON, DEPT MAT SCI & ENGN, SEATTLE, WA 98195 USA. RP Henager, CH (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. OI Henager, Chuck/0000-0002-8600-6803 NR 46 TC 14 Z9 14 U1 0 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD APR PY 1996 VL 27 IS 4 BP 839 EP 849 DI 10.1007/BF02649751 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA UG103 UT WOS:A1996UG10300003 ER PT J AU AsokaKumar, P AF AsokaKumar, P TI Studies of near-surface and interface defects using positron beams SO METALS MATERIALS AND PROCESSES LA English DT Article DE positron beams; semiconductors; overlayers; surfaces; interfaces; defects ID OXIDE-SEMICONDUCTOR STRUCTURES; ELECTRON-SPIN RESONANCE; SI/SIO2 INTERFACE; POINT-DEFECTS; GROWN SILICON; IMPLANTED SI; THIN-FILMS; EPITAXY; GAAS; HYDROGEN AB Positron Annihilation Spectroscopy has been increasingly used as a defect probe in studying overlayers, interfaces, and buried regions of semiconductors. A variable-energy positron beam provides a depth-resolved, non-destructive probe for defects in a semiconductor system. In bulk crystalline materials, the technique can detect defects at a concentration as low as 5 x 10(15) cm(-3). This review highlights the success of poistron beam studies in revealing the nature, concentration, and spatial distribution of defects in the near-surface and interface regions of important semiconductor systems. RP AsokaKumar, P (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RI Schaff, William/B-5839-2009 NR 56 TC 0 Z9 0 U1 0 U2 0 PU MESHAP SCIENCE PUBLISHERS PI FORT, BOMBAY PA 75, 4TH FL, LAKSHMI BLDG, SIR P M ROAD,, FORT, BOMBAY 400 001, INDIA SN 0970-423X J9 MET MATER PROCESS JI Met. Mater. Proc. PD APR-JUN PY 1996 VL 8 IS 1 BP 93 EP 113 PG 21 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA WN121 UT WOS:A1996WN12100008 ER PT J AU Torres, LFB Waga, I AF Torres, LFB Waga, I TI Decaying Lambda cosmologies and statistical properties of gravitational lenses SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE cosmology, theory; gravitational lensing ID INTERGALACTIC MEDIUM; ELLIPTICAL GALAXIES; DARK MATTER; CONSTANT; UNIVERSE; CONSEQUENCES; DENSITY; LIMITS; MODELS; FIELD AB In this paper we investigate the statistical properties of gravitational lenses for models in which a cosmological term decreases with time as Lambda proportional to a(-m), where a is the scale factor, and m is a parameter (0 less than or equal to m < 3). We show that for given low values of the present matter density parameter Omega(m0), there is a wide range of values for m for which the lensing rate is significantly smaller than that in cosmological constant (Lambda) models. We also show that models with low Omega(m0) and m greater than or similar to 1 have a high likelihood of reproducing the observed lens statistics in the Hubble Space Telescope Snapshot Survey (HSTSS). C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Torres, LFB (reprint author), FED UNIV RIO DE JANEIRO,INST FIS,BR-21943 RIO JANEIRO,BRAZIL. RI Waga, Ioav/B-6288-2014 NR 62 TC 27 Z9 28 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1996 VL 279 IS 3 BP 712 EP 726 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UF154 UT WOS:A1996UF15400010 ER PT J AU Priedhorsky, WC Peele, AG Nugent, KA AF Priedhorsky, WC Peele, AG Nugent, KA TI An X-ray all-sky monitor with extraordinary sensitivity SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE instrumentation, detectors; space vehicles; telescopes; surveys; X-rays, general ID GALACTIC LATITUDE ABSOLUTE-VALUE-OF-B-LESS-THAN-10-DEGREES; LARGE MAGELLANIC CLOUD; V 3A CATALOG; N-LOG-S; MICROCHANNEL PLATES; POSITION DETECTION; LUMINOSITY; GALAXIES; PULSARS; BURSTS AB We set forth a conceptual design for an X-ray all-sky monitor based on lobster-eye wide-field telescopes. This instrument, suitable for a small satellite, would monitor the flux of objects as faint as 2 x 10(-12) erg cm(-2) s(-1) (0.5-2.4 keV) on a daily basis with a signal-to-noise ratio of 5, Sources would be located to 1-2 arcmin. Detailed simulations show that cross-talk from the cruciform lobster images would not significantly compromise performance, At this sensitivity limit, we could monitor not just X-ray binaries, but also fainter classes of X-ray sources, Hundreds of active galactic nuclei, coronal sources and cataclysmic variables could be tracked on a daily basis. Large numbers of fast transients should be visible, including gamma-ray bursts and the soft X-ray breakout of nearby Type II supernovae. C1 UNIV MELBOURNE,SCH PHYS,PARKVILLE,VIC 3052,AUSTRALIA. RP Priedhorsky, WC (reprint author), LOS ALAMOS NATL LAB,MAIL STOP D436,LOS ALAMOS,NM 87545, USA. RI Nugent, Keith/J-2699-2012; Nugent, Keith/I-4154-2016; OI Nugent, Keith/0000-0003-1522-8991; Nugent, Keith/0000-0002-4281-3478; Priedhorsky, William/0000-0003-0295-9138 NR 70 TC 59 Z9 60 U1 1 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1996 VL 279 IS 3 BP 733 EP & PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UF154 UT WOS:A1996UF15400012 ER PT J AU Sylvester, RJ Skinner, CJ Barlow, MJ Mannings, V AF Sylvester, RJ Skinner, CJ Barlow, MJ Mannings, V TI Optical, infrared and millimetre-wave properties of Vega-like systems SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE circumstellar matter; stars, evolution; planetary systems; infrared, stars ID T-TAURI STARS; SPECTRAL IRRADIANCE CALIBRATION; PICTORIS CIRCUMSTELLAR DISK; PHOTOMETRIC STANDARD STARS; MAIN-SEQUENCE STARS; BETA-PICTORIS; CELESTIAL EQUATOR; MOLECULAR CLOUDS; IRAS; DUST AB Vega-like stars are main-sequence stars that exhibit excess infrared emission due to dust grains which are believed to be distributed in circumstellar discs. To facilitate modelling of the properties of the discs and of their constituent grains, we have assembled a new observational database for a large sample of candidate Vega-like systems, which comprises UBVRI optical photometry, JHKLL'M near-IR photometry, mid-IR spectra, and mm/submm-wave photometry, Although our sample of stars are all believed to be main-sequence, it is noteworthy that most have large IR excesses compared with the 'prototype' Vega-like stars, and they may therefore be somewhat younger. The excess fluxes are, in a few cases, greater than can be explained by emission from pure radiation-reprocessing discs, even in the optically thick case, suggesting additional contributions by extended envelopes and/or flux generated by viscous dissipation in a flared accretion disc. The dereddened optical colours are, for the whole sample, entirely consistent with photospheric emission from main-sequence stars. The near-IR photometry revealed that 9 out of 23 Vega-like sources exhibit excess near-IR emission with colours resembling those of Herbig Ae/Be systems, while the rest show only photospheric emission at near-IR wavelengths. Our mid-IR spectra reveal that most of the discs show combinations of silicate and unidentified infrared (UIR) emission features, demonstrating the presence of both oxygen- and carbon-rich dust species. Our new mm/submm photometry indicates that most of the sample display small mm-wave spectral indices, implying that they possess grains that are much larger than those found in the interstellar medium, with implications for past or on-going grain growth within the discs, Fractional excess luminosities, L(IR)/L star, were calculated from the optical photometry. For some of our sources, values similar to 10(-5) - 10(-3) were found, similar to those of the prototype Vega-like systems. Others gave L(IR)/L star > 0.25, the maximum value for a flat passively reprocessing disc, Two sources gave L(IR)/L star > 0.5, the maximum for a flared reprocessing disc. These large values are comparable to those of Herbig Ae/Be and T Tauri stars, and suggest that some of the excess IR emission from these sources is due to disc accretion or the presence of circumstellar envelopes. C1 LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94551 USA. RP Sylvester, RJ (reprint author), UNIV LONDON UNIV COLL, DEPT PHYS & ASTRON, GOWER ST, LONDON WC1E 6BT, ENGLAND. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 90 TC 192 Z9 192 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1996 VL 279 IS 3 BP 915 EP 939 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA UF154 UT WOS:A1996UF15400026 ER PT J AU Jesson, DE Chen, KM Pennycook, SJ AF Jesson, DE Chen, KM Pennycook, SJ TI Kinetic pathways to strain relaxation in the Si-Ge system SO MRS BULLETIN LA English DT Article ID DISLOCATION NUCLEATION; MORPHOLOGICAL INSTABILITY; MONOLAYER COVERAGE; INAS ISLANDS; QUANTUM DOTS; SURFACE CUSP; GROWTH; EVOLUTION; GAAS; EPITAXY C1 OAK RIDGE NATL LAB,ELECTRON MICROSCOPY GRP,OAK RIDGE,TN 37831. RP Jesson, DE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. OI Jesson, David/0000-0003-0897-1445 NR 31 TC 109 Z9 109 U1 4 U2 16 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 APR PY 1996 VL 21 IS 4 BP 31 EP 37 PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA VA230 UT WOS:A1996VA23000015 ER PT J AU Moya, MM Hush, DR AF Moya, MM Hush, DR TI Network constraints and multi-objective optimization for one-class classification SO NEURAL NETWORKS LA English DT Article DE one-class classification; one-class generalization; second-order networks; network constraints; multiple objective optimization; identification; automatic target recognition ID CATEGORY AB This paper introduces a constrained second-order network with a multiple objective learning algorithm that forms closed hyperellipsoidal decision boundaries for one-class classification. The network architecture has uncoupled constraints that give independent control over each decision boundary's size, shape, position, and orientation. The architecture together with the learning algorithm guarantee the formation of positive definite eigenvalues for closed hyperellipsoidal decision boundaries. The learning algorithm incorporates two criteria, one that seeks to minimize classification mapping error and another that seeks to minimize the size of the decision boundaries. We consider both additive combinations and multiplicative combinations of the individual criteria, and we present empirical evidence for selecting functional forms of the individual objectives that are bounded and normalized. The resulting multiple objective criterion allows the decision boundaries to increase or decrease in size as necessary to achieve both within-class generalization and out-of-class generalization without requiring the use of non-target patterns in the training set. The resulting network learns compact closed decision boundaries when trained with target data only. We show results of applying the network to the Iris data set (Fisher (1936), Annals of Eugenics, 7(2), 179-188). Advantages of this approach include its inherent ability for one-class generalization, freedom from characterizing the non-target class, and the ability to form closed decision boundaries for multi-modal classes that are more complex than hyperspheres without requiring inversion of large matrices. Published by Elsevier Science Ltd. C1 UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. RP Moya, MM (reprint author), SANDIA NATL LABS,IMAGE & SIGNAL PROC SYST DEPT 1,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 31 TC 41 Z9 43 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0893-6080 J9 NEURAL NETWORKS JI Neural Netw. PD APR PY 1996 VL 9 IS 3 BP 463 EP 474 DI 10.1016/0893-6080(95)00120-4 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA UK045 UT WOS:A1996UK04500009 ER PT J AU Probert, PH Oliva, SP Winz, GR Hoffman, DJ Caughman, JBO Gardner, WL AF Probert, PH Oliva, SP Winz, GR Hoffman, DJ Caughman, JBO Gardner, WL TI Design and initial tests of a low voltage stacked stripline fast wave launcher in the Phaedrus-T tokamak SO NUCLEAR FUSION LA English DT Article ID ALFVEN-WAVE; ANTENNA AB A new type of antenna for launching waves in the ion cyclotron frequency range in toroidal plasma devices has been developed and tested in the Phaedrus-T tokamak. This antenna, a stacked stripline (SSL), generates a radiofrequency (RF) magnetic field similar to that of a conventional strap antenna but develops voltages 2 orders of magnitude less, and can operate without a Faraday shield. In comparison tests with a conventional strap antenna at a power level of 60 kW, the RF induced density rise and the impurity production (as indicated by soft X ray and loop voltage increases) were reduced by a factor of 3. In addition, it was demonstrated that capacitive loading effects were reduced or eliminated in comparison with those observed on a conventional strap antenna operated without a Faraday shield, and in the operation of a pair of SSL antennas at 90 degrees phase small current drive effects were observed. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. RP Probert, PH (reprint author), UNIV WISCONSIN,DEPT NUCL ENGN & ENGN PHYS,MADISON,WI 53706, USA. RI Caughman, John/R-4889-2016 OI Caughman, John/0000-0002-0609-1164 NR 16 TC 0 Z9 0 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 1996 VL 36 IS 4 BP 421 EP 433 DI 10.1088/0029-5515/36/4/I02 PG 13 WC Physics, Fluids & Plasmas SC Physics GA XY883 UT WOS:A1996XY88300002 ER PT J AU Janos, AC Fredrickson, ED Budny, RV Darrow, DS McGuire, KM Zweben, SJ AF Janos, AC Fredrickson, ED Budny, RV Darrow, DS McGuire, KM Zweben, SJ TI Characterization of alpha particle loss during disruptions in TFTR during deuterium-tritium operation SO NUCLEAR FUSION LA English DT Article ID FUSION-TEST-REACTOR; DT EXPERIMENTS; PRODUCTS; TOKAMAK; DETECTORS; PLASMA AB The timing of alpha losses, with respect to the various phases of a disruption, and the impact location of the losses are characterized during high fusion power operation of TFTR with deuterium and tritium fuels. Characterization of alpha losses is important for the design of future fusion devices such as ITER. In addition, characterization of the alpha losses with respect to the disruption evolution helps in the understanding of the dynamics of the disruption process and related MHD events such as sawtooth crashes. Disruptions are characterized as having several standard phases, applicable to most disruptions in all tokamaks: precursor, thermal quench(es) and current quench. Most of the losses are observed to occur during the thermal quench phase(s). In high beta disruptions, alpha losses start abruptly during the growth of MHD precursors, just before the onset of the thermal quench. The initial burst of losses, lasting as little as 100 mu s, can release a significant fraction (one third) of the total disruption induced losses during the thermal quench. An inventory of alpha particles suggests that the alpha loss distribution during disruptions might be quite different from that expected during non-disruptive discharges. There are no obvious differences between fast fusion product losses during deuterium-deuterium (DD) and deuterium-tritium (DT) disruptions, aside from the large alpha loss component in DT discharges. RP Janos, AC (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 30 TC 2 Z9 2 U1 0 U2 4 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 APR PY 1996 VL 36 IS 4 BP 475 EP 495 DI 10.1088/0029-5515/36/4/I07 PG 21 WC Physics, Fluids & Plasmas SC Physics GA XY883 UT WOS:A1996XY88300007 ER PT J AU Schaffer, MJ Maingi, R Hyatt, AW Mahdavi, MA AF Schaffer, MJ Maingi, R Hyatt, AW Mahdavi, MA TI Increased divertor exhaust by electrical bias in DIII-D SO NUCLEAR FUSION LA English DT Letter ID TOKAMAKS; REDUCTION; EDGE; TDEV AB The particle exhaust rate of the DIII-D tokamak divertor cryopump system was investigated as a function of gas-puff-regulated core plasma line-averaged density, divertor electrical bias potential and position of the divertor strike point with respect to the pump entrance aperture. The experiment was done with rapidly ELMing H mode plasmas. Divertor bias approximately doubled the maximum achievable exhaust rate and also reduced its sensitivity to the strike point position. The achievable exhaust rate varied roughly as the third power of the core plasma density. C1 OAK RIDGE ASSOCIATED UNIV,OAK RIDGE,TN. RP Schaffer, MJ (reprint author), GEN ATOM CO,SAN DIEGO,CA 92186, USA. NR 25 TC 4 Z9 4 U1 0 U2 4 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 APR PY 1996 VL 36 IS 4 BP 496 EP 502 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XY883 UT WOS:A1996XY88300008 ER PT J AU Darrow, DS Majeski, R Fisch, NJ Heeter, RF Herrmann, HW Herrmann, MC Zarnstorff, MC Zweben, SJ AF Darrow, DS Majeski, R Fisch, NJ Heeter, RF Herrmann, HW Herrmann, MC Zarnstorff, MC Zweben, SJ TI Enhanced loss of fast ions during mode conversion ion Bernstein wave heating in TFTR SO NUCLEAR FUSION LA English DT Letter ID FUSION PRODUCTS AB A strong interaction of fast ions with ion Bernstein waves has been observed in TFTR. It results in a large increase in the fast ion loss rate and heats the lost particles to several megaelectronvolts. The lost ions are observed at the passing-trapped boundary and appear to be either DD fusion produced tritons or accelerated deuterium neutral beam ions. Under some conditions, enhanced loss of DT alpha particles is also seen. The losses provide experimental support for some of the elements required for alpha energy channelling. RP Darrow, DS (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 12 TC 22 Z9 23 U1 1 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD APR PY 1996 VL 36 IS 4 BP 509 EP 513 DI 10.1088/0029-5515/36/4/I10 PG 5 WC Physics, Fluids & Plasmas SC Physics GA XY883 UT WOS:A1996XY88300010 ER PT J AU Nagayama, Y Taylor, G Yamada, M Fredrickson, ED Janos, AC McGuire, KM AF Nagayama, Y Taylor, G Yamada, M Fredrickson, ED Janos, AC McGuire, KM TI ECE image reconstruction of partial sawtooth crashes in ohmic plasmas SO NUCLEAR FUSION LA English DT Letter ID FUSION TEST REACTOR; COMPOUND SAWTEETH; BALLOONING MODES; BETA-PLASMAS; TOKAMAK; OSCILLATIONS; TFTR; TOMOGRAPHY AB Partial sawtooth crashes in ohmic plasmas on TFTR are analysed using the high resolution electron cyclotron emission (ECE) image reconstruction technique. During the partial sawtooth crash, (m, n) = (2, 2) or (3, 3) modes are dominant. The (1, 1) mode occurs after the partial crash. The partial sawtooth crash can be explained by the flattening of the (2, 2) or (3, 3) islands due to the localized reconnection. C1 PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RI Yamada, Masaaki/D-7824-2015 OI Yamada, Masaaki/0000-0003-4996-1649 NR 16 TC 19 Z9 19 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 APR PY 1996 VL 36 IS 4 BP 521 EP 526 DI 10.1088/0029-5515/36/4/I12 PG 6 WC Physics, Fluids & Plasmas SC Physics GA XY883 UT WOS:A1996XY88300012 ER PT J AU Lundin, M Contin, A Dellacasa, G DeSalvo, R Gallio, M Gorodetzky, P Helleboid, JM Johnson, KF Juillot, P Lazic, D Musso, A Vercellin, E White, S AF Lundin, M Contin, A Dellacasa, G DeSalvo, R Gallio, M Gorodetzky, P Helleboid, JM Johnson, KF Juillot, P Lazic, D Musso, A Vercellin, E White, S TI On the electromagnetic energy resolution of Cherenkov-fiber calorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Electromagnetic calorimeters which sample the Cherenkov radiation of shower particles in optical fibers operate in a markedly different manner from calorimeters which rely on the dE/dx of shower particles. The well-understood physics of electromagnetic shower development is applied to the case of Cherenkov-fiber calorimetry (also known as quartz fiber calorimetry) and the results of systematically performed studies are considered in detail to derive an understanding of the critical parameters involved in energy measurement using such calorimeters. A quantitative parameterization of Cherenkov-fiber calorimetry electromagnetic energy resolution is proposed and compared with existing experimental results. C1 CRN,STRASBOURG,FRANCE. UNIV STRASBOURG 1,STRASBOURG,FRANCE. UNIV BOLOGNA,BOLOGNA,ITALY. IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. IST NAZL FIS NUCL,I-10125 TURIN,ITALY. UNIV TURIN,TURIN,ITALY. IST NAZL FIS NUCL,PISA,ITALY. CERN,CH-1211 GENEVA,SWITZERLAND. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. BROOKHAVEN NATL LAB,UPTON,NY 11973. OI Lundin, Mark/0000-0001-5936-7649 NR 29 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 APR 1 PY 1996 VL 372 IS 3 BP 359 EP 367 DI 10.1016/0168-9002(95)01517-5 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ926 UT WOS:A1996UJ92600006 ER PT J AU Eremin, V Strokan, N Verbitskaya, E Li, Z AF Eremin, V Strokan, N Verbitskaya, E Li, Z TI Development of transient current and charge techniques for the measurement of effective net concentration of ionized charges (N-eff) in the space charge region of p-n junction detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SILICON DETECTORS AB Transient current and charge techniques (TCT/TChT) have been developed as alternatives to the standard C-V measurements for measurements of the effective net concentration of ionized charges (N-eff) in the space charge region (SCR) of Si p-n junction detectors, especially for heavily irradiated detectors. This paper contains the physical background of the techniques, modeling of current and charge pulse response, and applications of the methods to the characterizations of silicon planar detectors designed for high energy physics. C1 BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. RUSSIAN ACAD SCI, AF IOFFE PHYSICOTECH INST, ST PETERSBURG 196140, RUSSIA. RI Verbitskaya, Elena/D-1521-2014 NR 18 TC 103 Z9 103 U1 0 U2 2 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 APR 1 PY 1996 VL 372 IS 3 BP 388 EP 398 DI 10.1016/0168-9002(95)01295-8 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ926 UT WOS:A1996UJ92600010 ER PT J AU Sturhahn, W Toellner, TS Quast, KW Rohlsberger, R Alp, EE AF Sturhahn, W Toellner, TS Quast, KW Rohlsberger, R Alp, EE TI Reduction of detector noise in experiments with synchrotron radiation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID TIME RESOLUTION AB Noise reduction in existing detector systems at synchrotron radiation facilities car. be accomplished by utilizing the pulsed structure of the synchrotron radiation. We present the working principle of this technique and explain its feasibility for use with common X-ray detectors that provide single photon counting. RP Sturhahn, W (reprint author), ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439, USA. RI Rohlsberger, Ralf/J-4173-2013 OI Rohlsberger, Ralf/0000-0001-6005-5183 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 APR 1 PY 1996 VL 372 IS 3 BP 455 EP 457 DI 10.1016/0168-9002(95)01399-7 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ926 UT WOS:A1996UJ92600017 ER PT J AU Neumann, HB Schneider, JR Sussenbach, J Stock, SR Rek, ZU AF Neumann, HB Schneider, JR Sussenbach, J Stock, SR Rek, ZU TI Si-TaSi2 in situ composites: A new monochromator material for hard X-rays SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA Russian DT Article AB The Si matrix of two Si-TaSi2 in situ composites grown in the 111 direction have been characterized by means of triple axis diffractometry using synchrotron radiation with photon energies of 120 and 160 keV. The Si matrix is compressed in the growth direction and dilated along two orthogonal directions perpendicular to it. The rocking curves show no grains or peaksplitting over a large area of the sample, and their full width half maximum is of the order of similar to 0.03 degrees. The integrated reflecting power in this energy range is about 400 times larger than the theoretical value for perfect Si crystals. These properties make Si-TaSi2 composites an interesting monochromator material for diffraction experiments with hard X-rays when intermediate resolution is required. In addition to the properties of the Si matrix, diffraction from the TaSi2 rods has been studied. They are highly oriented crystals and cause strongly anisotropic deformation in the Si matrix, which opens the possibility of varying the k-space resolution of the diffractometer merely by tilting the monochromator, and, in the case of a triple crystal diffractometer, by tilting the analyzer crystal as well. C1 DESY,HAMBURGER SYNCHROTRONSTRAHLUNGSLAB HASYLAB,D-22603 HAMBURG,GERMANY. GEORGIA INST TECHNOL,SCH MAT SCI & ENGN,ATLANTA,GA 30332. SSRL,STANFORD,CA 94309. NR 16 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 1 PY 1996 VL 372 IS 3 BP 551 EP 555 DI 10.1016/0168-9002(95)01448-9 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UJ926 UT WOS:A1996UJ92600028 ER PT J AU Janssens, K Aerts, A Vincze, L Adams, F Yang, C Utui, R Malmqvist, K Jones, KW Radtke, M Garbe, S Lechtenberg, F Knochel, A Wouters, H AF Janssens, K Aerts, A Vincze, L Adams, F Yang, C Utui, R Malmqvist, K Jones, KW Radtke, M Garbe, S Lechtenberg, F Knochel, A Wouters, H TI Corrosion phenomena in electron, proton and synchrotron X-ray microprobe analysis of Roman glass from Qumran, Jordan SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT VIIth International Conference on Particle Induced X-ray Emission and Its Analytical Applications CY MAY 26-30, 1995 CL ABANO TERME, ITALY SP Ist Nazl Fis Nucl, Italy, Univ Padova, Italy, Ruder Boskovic Inst, Croatia, Int Atom Energy Agcy, Austria AB A series of 89 glass fragments of Roman glass are studied using electron, proton and synchrotron radiation induced X-ray emission from microscopic areas on the sample surface. The glass originates from Qumran, Jordan and was buried for 1900 years. The weathering layers that result from the extended contact with ground water have been studied, next to the trace composition of the original glass of these pieces. The latter information indicates that at Qumran, large quantities of glass objects were being used in Ancient times. Cross-sectional profiles of the glass show a complex migration behaviour of various groups of major and trace elements. C1 LUND UNIV,DEPT NUCL PHYS,LUND,SWEDEN. BROOKHAVEN NATL LAB,UPTON,NY. UNIV HAMBURG,DEPT CHEM,HAMBURG,GERMANY. NATL INST CULTURAL HERITAGE,BRUSSELS,BELGIUM. RP Janssens, K (reprint author), UNIV ANTWERP,DEPT CHEM,ANTWERP,BELGIUM. RI Janssens, Koen/B-8049-2011 OI Janssens, Koen/0000-0002-6752-6408 NR 6 TC 20 Z9 20 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 APR PY 1996 VL 109 BP 690 EP 695 DI 10.1016/0168-583X(95)00993-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UV444 UT WOS:A1996UV44400132 ER PT J AU Bishop, A Satyamurthy, N Bida, G Phelps, M Barrio, JR AF Bishop, A Satyamurthy, N Bida, G Phelps, M Barrio, JR TI Metals suitable for fluorine gas target bodies: First use of aluminum for the production of [F-18]F-2 SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE [F-18]F-2 target; aluminum; silver; electroformed nickel; Langmuir-Rideal mechanism ID REGIOSELECTIVE RADIOFLUORODESTANNYLATION; F-18; RECOMBINATION; 6-FLUORO-L-DOPA; ATOMS AB A comprehensive evaluation of different metals (aluminum, silver, copper, nickel, and gold plated copper) was undertaken for the fabrication of target bodies with straight and conical bore shapes for the production of [F-18]F-2 via the Ne-20(d,alpha)F-18 nuclear reaction. Of these metals, aluminum, silver and copper have never been used for the production of [F-18]F-2. All these target bodies were easily passivated using a mild beam-induced plasma technique in the presence of 1% F-2 in neon or argon. The recovery of F-18 activity was higher with electroformed nickel and silver bodies, probably due to favorable thermal conductivities. Aluminum proved to be a useful material for fluorine gas targets. The consistent recovery of F-18 activities, ease and low cost of manufacturing and low nuclear activation properties all make aluminum an ideal choice for fluorine gas targetry. To our knowledge, this investigation is the first to highlight the use of aluminum as a target body material for the routine production of [F-18]F-2. A reasonable mechanism based on the Langmuir-Rideal surface atom recombination is also proposed for the behavior of [F-18]F-2 recovery from a nickel target body. C1 UNIV CALIF LOS ANGELES,SCH MED,DIV NUCL MED,DEPT MOL & MED PHARMACOL,LOS ANGELES,CA 90095. US DOE,LAB STRUCT BIOL & MOL MED,LOS ANGELES,CA 90095. BIOMED RES FDN NW LOUISIANA,SHREVEPORT,LA 71103. FU NINDS NIH HHS [P01-NS-15654] NR 56 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD APR PY 1996 VL 23 IS 3 BP 181 EP 188 DI 10.1016/0969-8051(95)02038-1 PG 8 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UH948 UT WOS:A1996UH94800001 PM 8782225 ER PT J AU Bishop, A Satyamurthy, N Bida, G Hendry, G Phelps, M Barrio, JR AF Bishop, A Satyamurthy, N Bida, G Hendry, G Phelps, M Barrio, JR TI Proton irradiation of [O-18]O-2: Production of [F-18]F-2 and [F-18]F-2+[F-18]OF2 SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE [F-18]F-2; [F-18]OF2; single-step irradiation; two-step irradiation; aluminum target; Mechanism of OF2 formation ID REGIOSELECTIVE RADIOFLUORODESTANNYLATION; ELEMENTAL FLUORINE; GAS TARGETS; F-18; PENETRATION AB The production of F-18 electrophilic reagents via the O-18(p,n)F-18 reaction has been investigated in small-volume target bodies made of aluminum, copper, gold plated copper and nickel, having straight or conical bore shapes. Three irradiation protocols-single-step, two-step and modified two-step-were used for the recovery of the F-18 activity. The single-step irradiation protocol was tested in all the target bodies. Based on the single step performance, aluminum targets were utilized extensively in the investigation of the two step and modified two-step irradiation protocols, With an 11-MeV cyclotron and using the two-step irradiation protocol, >1Ci [F-18]F-2 was recovered reproducibly from an aluminum target body, Probable radical mechanisms for the formation of OF2 and FONO2 (fluorine nitrate) in the single-step and modified two step targets are proposed based on the amount of ozone generated and the nitrogen impurity present in the target gases, respectively. C1 UNIV CALIF LOS ANGELES,SCH MED,DIV NUCL MED,DEPT MOL & MED PHARMACOL,LOS ANGELES,CA 90095. US DOE,LAB STRUCT BIOL & MOL MED,LOS ANGELES,CA 90095. BIOMED RES FDN NW LOUISIANA,SHREVEPORT,LA 71103. CYCLOTRON INC,NAPA,CA 94558. FU NINDS NIH HHS [P01-NS-15654] NR 70 TC 18 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD APR PY 1996 VL 23 IS 3 BP 189 EP 199 DI 10.1016/0969-8051(95)02037-3 PG 11 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UH948 UT WOS:A1996UH94800002 PM 8782226 ER PT J AU Luo, H Hasan, A Sood, V McRee, RC Zeeberg, B Reba, RC McPherson, DW Knapp, FF AF Luo, H Hasan, A Sood, V McRee, RC Zeeberg, B Reba, RC McPherson, DW Knapp, FF TI Evaluation of 1-azabicyclo[2.2.2]oct-3-yl alpha-fluoroalkyl-alpha-hydroxy-alpha-phenylacetates as potential ligands for the study of muscarinic receptor density by positron emission tomography SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE fluoroalkyl group; QNB analogues; fluorine-18; PET; muscarinic receptor ID ACETYLCHOLINE-RECEPTORS; ALZHEIMERS-DISEASE; 3-QUINUCLIDINYL BENZILATE; OPTICAL ISOMERS; INVIVO; BINDING; BRAIN; BIODISTRIBUTION; ANTAGONISTS; EXPRESSION AB Both 1-azabicyclo[2.2.2]oct-3-yl alpha-(1-fluoroeth-2-yl)-alpha-hydroxy-alpha-phenylaceta (FQNe, 5) and 1-azabicyclo[2.2.2]oct 3 yl alpha-(1-fluoropent-5-yl)-alpha-hydroxy-alpha-phenylacetate (FRNPe, 6) were prepared and evaluated as potential candidates for the determination of muscarinic cholinergic receptor (mAChR) density by positron emission tomography (PET), The results of in vitro binding assays demonstrated that although both 5 and 6 had high binding affinities for m, and m, mAChR subtypes, 6 displayed a higher affinity (nM, m(1); K-D, 0.45, m(2); K-D, 3.53) as compared to 5 (nM, m(1); K-D, 12.5, m(2); K-D, 62.8). It was observed that pretreatment of female Fisher rats with either 5 or 6 prior to the i.v. administration of Z-(-)(-)-[I-113]-IQNP, a high-affinity muscarinic ligand, significantly blocked the uptake of radioactivity in the brain and heart measured 3 h postinjection of the radiolabeled ligand. These new fluoro QNB analogues represent important target ligands for evaluation as potential receptor imaging agents in conjunction with PET. C1 OAK RIDGE NATL LAB,HLTH SCI RES DIV,NUCL MED GRP,OAK RIDGE,TN 37831. GEORGE WASHINGTON UNIV,SCH MED,DIV NUCL MED,RADIOPHARMACEUT CHEM SECT,WASHINGTON,DC 20037. UNIV CHICAGO,DEPT RADIOL,NUCL MED SECT,CHICAGO,IL 60637. RI Sood, Vinay/B-7109-2008 FU NINDS NIH HHS [NS-22215] NR 52 TC 3 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD APR PY 1996 VL 23 IS 3 BP 267 EP 276 DI 10.1016/0969-8051(95)02066-7 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UH948 UT WOS:A1996UH94800012 PM 8782236 ER PT J AU Galynker, I Schlyer, DJ Dewey, SL Fowler, JS Logan, J Gatley, J MacGregor, RR Ferrieri, RA Holland, MJ Brodie, J Simon, E Wolf, AP AF Galynker, I Schlyer, DJ Dewey, SL Fowler, JS Logan, J Gatley, J MacGregor, RR Ferrieri, RA Holland, MJ Brodie, J Simon, E Wolf, AP TI Opioid receptor imaging and displacement studies with [6-O-[C-11]methyl]buprenorphine in baboon brain SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE opioid receptor; buprenorphine; baboon; brain ID POSITRON EMISSION TOMOGRAPHY; C-11 DIPRENORPHINE; OPIATE RECEPTORS; RHESUS-MONKEYS; BUPRENORPHINE; BINDING; INVIVO; PET; BUPRENORPHINE; PHARMACOLOGY AB Buprenorphine (BPN) is a mixed opiate agonist-antagonist used as an analgesic and in the treatment of opiate addiction. We have used [6-O-[C-11]methyl]buprenorphine ([C-11]BPN) to measure the regional distribution in baboon brain, the test-retest stability of repeated studies in the same animal, the displacement of the labeled drug by naloxone in vivo, and the tissue distribution in mice, The regional distribution of radioactivity in baboon brain determined with PET was striatum > thalamus > cingulate gyrus > frontal cortex > parietal cortex > occipital cortex > cerebellum, This distribution corresponded to opiate receptor density and to previously published data (37). The tracer uptake in adult female baboons showed no significant variation in serial scans in the same baboon with no intervention in the same scanning session. HPLC analysis of baboon plasma showed the presence of labeled metabolites with 92% +/- 2.2% and 43% +/- 14.4% of the intact tracer remaining at 5 and 30 min, respectively. Naloxone, an opiate receptor antagonist, administered 30-40 min after tracer injection at a dose of 1.0 mg/kg i.v., reduced [C-11]BPN binding in thalamus, striatum, cingulate gyrus, and frontal cortex to values 0.25 to 0.60 of that with no intervention. There were minimal (<15%) effects on cerebellum, Naloxone treatment significantly reduced the slope of the Patlak plot in receptor-containing regions. These results demonstrate that [C-11]BPN can be displaced by naloxone in vivo, and they affirm the feasibility of using this tracer and displacement methodology for short-term kinetics studies with PET. Mouse tissue distribution data were used to estimate the radiation dosimetry to humans. The critical organ was the small intestine, with a radiation dose estimate to humans of 117 nrad/mCi. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. NYU,NEW YORK,NY 10016. BETH ISRAEL HOSP,NEW YORK,NY 10003. FU NINDS NIH HHS [NS-15638] NR 41 TC 19 Z9 21 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD APR PY 1996 VL 23 IS 3 BP 325 EP 331 DI 10.1016/0969-8051(95)02087-X PG 7 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UH948 UT WOS:A1996UH94800020 PM 8782244 ER PT J AU Susskind, H Weber, DA Ivanovic, M Wong, CTC DeHaan, CE Gavin, PR AF Susskind, H Weber, DA Ivanovic, M Wong, CTC DeHaan, CE Gavin, PR TI Quantitative I-123 IMP and Tc-99m HMPAO imaging in the dog following cocaine administration SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article DE cocaine; dog model; I-123 IMP; Tc-99m HMPAO; rCBF ID CEREBRAL BLOOD-FLOW; POSITRON EMISSION TOMOGRAPHY; BRAIN; SPECT; PERFUSION; IMAGES; PET AB SPECT and associated imaging procedures were used in beagle dogs to (1) evaluate the uptake, distribution, and clearance properties of i.v.-injected I-123 IMp (IMP) and Tc-99m HMPAO (HMPAO) in the brain, lungs, liver, and kidneys; (2) quantify the acute effects (after 15 sec) of very low doses (0.5 or 1.0 mg/kg) cocaine on the kinetics and localization properties of IMP and HMPAO; and (3) evaluate comparative imaging properties of IMP and HMPAO for measuring regional cerebral blood flow (rCBF), Regional and global uptake and localization of IMP or HMPAO were evaluated in control studies using dynamic planar (0-30 min) and SPECT imaging (at 35 min). The regional distribution properties of IMP and HMPAO in the brain were estimated from regions of interest (ROIs) drawn around anatomic structures on MR slices and manually registered with corresponding SPECT slices. Cocaine significantly reduced the 30-min IMP uptake in the brain and lungs by similar to 15%, but only slightly changed HMPAO uptake in the brain and other organs. In the control studies, the respective uptakes of LMP in the brain and lungs were 9 and 39% greater (P < 0.01) than those of HMPAO. In control SPECT studies, the highest uptake of IMP was observed in the thalamus and progressively less activity was observed in the parietal lobe, frontal lobe, cerebellum, occipital lobe, and entire brain; activity in the olfactory bulb was lower than in all other regions, Cocaine reduced IMP uptake in the cerebellum (p < 0.01), occipital lobe (p < 0.01), and entire brain (p < 0.05). IMP uptake (cpm/pixel-mCi) in the different brain regions was 1.3 to 2.1 times greater than that of HMPAO (p < 0.001), HMPAO uptake was more homogeneous throughout the gray matter of the brain; no significant uptake differences were observed among flagged regions. Results indicate that single, acute doses of cocaine, 0.5 and 1.0 mg/kg, significantly altered the uptake and localization properties of LMP in the dog's brain, lungs, liver, and kidneys, Variations in regional uptake of IMP in the parietal, frontal, and occipital lobes, cerebellum, and thalamus were greater than with HMPAO. C1 WASHINGTON STATE UNIV,DEPT VET CLIN MED & SURG,PULLMAN,WA 99163. RP Susskind, H (reprint author), BROOKHAVEN NATL LAB,CLIN RES CTR,BOX 5000,UPTON,NY 11973, USA. NR 29 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0883-2897 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD APR PY 1996 VL 23 IS 3 BP 343 EP 352 DI 10.1016/0969-8051(95)02097-7 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA UH948 UT WOS:A1996UH94800022 PM 8782246 ER EF