排序方式: 共有59条查询结果,搜索用时 14 毫秒
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Adler J Becker JJ Blaylock GT Bolton T Brient J Browder T Brown JS Bunnell KO Burchell M Burnett TH Cassell RE Coffman D Cook V Coward DH DeJongh F Dorfan DE Drinkard J Dubois GP Eigen G Einsweiler KF Eisenstein BI Freese T Gatto C Gladding G Grab C Hamilton RP Hauser J Heusch CA Hitlin DG Izen JM Kim PC Köpke L Li A Lockman WS Mallik U Matthews CG Mincer AI Mir R Mockett PM Mozley RF Nemati B Odian A Parrish L Partridge R Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL 《Physical review letters》1989,62(16):1821-1824
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Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Eigen G Eisenstein BI Freese T Gladding G Grab C Heusch CA Hitlin DG Izen JM Köpke L Li A Lockman WS Mallik U Matthews CG Mir R Mockett PM Mozley RF Nemati B Odian A Parker J Parrish L Partridge R Pitman D Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C Stockdale IE Stockhausen W Thaler JJ Toki W Tripsas B Villa F Wasserbaech S Wattenberg A Weinstein AJ 《Physical review letters》1987,58(21):2171-2174
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Bhattacharya M Goodman CD Raghavan RS Palarczyk M Garcia A Rapaport J van Heerden IJ Zupranski P 《Physical review letters》2000,85(21):4446-4449
We report a 0 degrees 176Yb(p,n)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1(+) states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem. 相似文献
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Lees JP Poireau V Tisserand V Garra Tico J Grauges E Martinelli M Milanes DA Palano A Pappagallo M Eigen G Stugu B Brown DN Kerth LT Kolomensky YG Lynch G Koch H Schroeder T Asgeirsson DJ Hearty C Mattison TS McKenna JA So RY Khan A Blinov VE Buzykaev AR Druzhinin VP Golubev VB Kravchenko EA Onuchin AP Serednyakov SI Skovpen YI Solodov EP Todyshev KY Yushkov AN Bondioli M Kirkby D Lankford AJ Mandelkern M Stoker DP Atmacan H Gary JW Liu F Long O Vitug GM Campagnari C Hong TM Kovalskyi D 《Physical review letters》2011,107(22):221803
We search for hadronic decays of a light Higgs boson (A(0)) produced in radiative decays of an Υ(2S) or Υ(3S) meson, Υ→γA(0). The data have been recorded by the BABAR experiment at the Υ(3S) and Υ(2S) center-of-mass energies and include (121.3±1.2)×10(6) Υ(3S) and (98.3±0.9)×10(6) Υ(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions B(Υ(nS)→γA(0))B(A(0)→hadrons) (n=2 or 3) that range from 1×10(-6) for an A(0) mass of 0.3 GeV/c(2) to 8×10(-5) at 7 GeV/c(2). 相似文献
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We consider diffraction by a semi-infinite crack located alonga fusion interface between two differing elastic media. Twotypes of crack, namely open and partially closed cracks, areinvestigated. An open crack is modelled by a stress-free contactboundary condition and a partially closed crack is modelledby a spring contact boundary condition. For the latter, thejump in the stress across the crack is assumed to be proportionalto the jump in the displacement across the crack. This situationarises in, for example, a K-weld where the fine grain of theparent material (for example, ferritic or forged austeniticsteel) is in stark contrast with the coarse-grained weld metal(for example, austenitic weld metal). In the metal weld thedirection of the grain axis varies through the metal. However,diffraction is a local phenomenon and so the austenitic steelis assumed to have a zonal axis so that it may be modelled bya transversely isotropic composite. The ferritic or forged austeniticsteel will be modelled as an isotropic material. 相似文献
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Schalk O Boguslavskiy AE Stolow A Schuurman MS 《Journal of the American Chemical Society》2011,133(41):16451-16458
The influence of through-bond interactions on nonadiabatic excited-state dynamics is investigated by time-resolved photoelectron spectroscopy (TRPES) and ab initio computation. We compare the dynamics of cyclohexa-1,4-diene, which exhibits a through-bond interaction known as homoconjugation (the electronic correlation between nonconjugated double bonds), with the nonconjugated cyclohexene. Each molecule was initially excited to a 3s Rydberg state using a 200 nm femtosecond pump pulse. The TRPES spectra of these molecules display similar structure and time constants on a subpicosecond time scale. Our ab initio calculations show that similar sets of conical intersections (a [1,2]- and [1,3]-hydrogen shift, as well as carbon-carbon bond cleavage) are energetically accessible to both molecules and that the geometry and orbital composition at the minimum energy crossing points to the ground state are directly analogous. These experimental and computational results suggest that the excited-state dynamics of cyclohexa-1,4-diene become localized at a single double bond and that the effects of through-bond interaction, dominant in the absorption spectrum, are absent in the excited-state dynamics. The notion of excited-state dynamics being localized at specific sites within the nuclear framework is analogous to the localization of light absorption by a subsystem within the molecule, designated a chromophore. We propose the utility of the analogous concept, denoted here as a dynamophore. 相似文献
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Closed vessel microwave-assisted wet digestion with simultaneous control of pressure and temperature in all vessels 总被引:2,自引:0,他引:2
M. Zischka Peter Kettisch Andreas Schalk Günter Knapp 《Fresenius' Journal of Analytical Chemistry》1998,361(2):90-95
A novel system for microwave-assisted wet digestion in closed vessels is described. Six pressure vessels made of quartz or
Hostaflon? TFM are placed in a special rotor in a microwave oven. During sample decomposition the pressure and temperature are measured
in each vessel, and the data are transferred from the rotor by means of infrared light to the control unit. This means that
no pneumatic or electronic connections to the vessels need to be established, providing very easy handling. The temperature
history of each vessel is recorded; so the progress of each sample digestion may be reconstructed later on. Thus the requirements
for quality control in sample digestion are available for the first time. For sample digestion at 75 bar and up to 280° C,
quartz vessels with 50 mL volume are used. Depending on the matrix, the maximum sample loading capacity is 1.2 g. TFM-vessels
with 100 mL volume work at 30 bar up to 240° C. The performance of the digestion system was tested with twelve standard reference
materials. The results closely matched the certified values.
Received: 18 September 1997 / Revised: 3 November 1997 / Accepted: 6 November 1997 相似文献
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Baltrusaitis RM Becker JJ Blaylock GT Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Cui H Del Papa C Dorfan DE Duncan AL Einsweiler KF Eisenstein BI Fabrizio R Gladding G Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Mockett PM Moss L Mozley RF Nappi A Odian A Partridge R Perrier J Plaetzer SA Richman JD Roehrig JR Russell JJ Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Sleeman JC Spadafora AL Thaler JJ Toki W Unno Y Villa F Wattenberg A 《Physical review letters》1985,55(17):1723-1726
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Adler J Becker JJ Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Duncan AL Eigen G Einsweiler KF Eisenstein BI Freese T Gladding G Grab C Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Izen JM Köpke L Li A Lockman WS Mallik U Matthews CG Mir R Mockett PM Mozley RF Nemati B Odian A Parrish L Partridge R Perrier J Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C 《Physical review letters》1988,60(2):89-92