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31.
John W. Moore Kenneth W. Hicks Robert G. Williams Kalle Gehring Sharon Pittinger John R. Vidolich Spencer Schubbe 《Trends in analytical chemistry : TRAC》1983,2(4):74-80
One problem in the use of stopped-flow rapid-mixing systems is that data can be collected much more rapidly than they can be digitized and analyzed. Microprocessor based systems can overcome this problem, but until now they have been expensive and have required experts to assemble the appropriate components. 相似文献
32.
We report on a high statistics search for the Ξ??(1860) resonance in Σ?-nucleus collisions at 340 GeV/c. No evidence for this resonance is found in our data sample which contains 676000 Ξ? candidates above bakground. For the decay channel Ξ??(1860)→Ξ? π ? and the kinematic range 0.15<xF<0.9 we find a 3σ upper limit for the production cross section of 3.1 and 3.5 μb per nucleon, for reactions with carbon and copper, respectively. 相似文献
33.
Zegers RG Sumihama M Ahn DS Ahn JK Akimune H Asano Y Chang WC Daté S Ejiri H Fujimura H Fujiwara M Hicks K Hotta T Imai K Ishikawa T Iwata T Kawai H Kim ZY Kino K Kohri H Kumagai N Makino S Matsumura T Matsuoka N Mibe T Miwa K Miyabe M Miyachi Y Morita M Muramatsu N Nakano T Niiyama M Nomachi M Ohashi Y Ooba T Ohkuma H Oshuev DS Rangacharyulu C Sakaguchi A Sasaki T Shagin PM Shiino Y Shimizu H Sugaya Y Toyokawa H Wakai A Wang CW Wang SC Yonehara K Yorita T Yoshimura M Yosoi M 《Physical review letters》2003,91(9):092001
Beam polarization asymmetries for the p(gamma-->,K+)Lambda and p(gamma-->,K+)Sigma(0) reactions are measured for the first time for E(gamma)=1.5-2.4 GeV and 0.6相似文献
34.
[reaction: see text] A series of 2-anilinotropones were synthesized via the palladium-catalyzed cross coupling of 2-triflatotropone and a wide variety of anilines, sterically hindered as well as electron-poor ones. 相似文献
35.
Polyurethane (PU) foams used in wound management are produced by a reaction between aromatic diisocyanates and polyether polyols. There is concern that residues of these starting materials, which may contain aromatic amine functionality, may leach from the finished polymer during in vivo applications. Furthermore, oligomers and additives may be leached from the PU system after the polymerization process is complete. Finished polymers have, therefore, been extracted with a range of solvents, such as water, diethyl ether and dilute HCl. The extracts were subjected to MALDI-MS (matrix-assisted laser desorption ionization mass spectrometry) analysis in an attempt to determine the amine and polyol functionality. Direct MALDI-MS analysis of the wound dressing extracts indicated the presence of components based on the polyols [corrected] used in the formulation of the foam. The spacing between the peaks identified the base monomer used in the polyol. MALDI-MS analysis of the fluorescamine derivatives of model amine compounds has demonstrated the anticipated increase in mass (278 for monoamines and 278 and 556 for diamines). Similar results were obtained from the derivatization of model polyols with phenyl isocyanate, where the mass shift (n x 119) was a direct measure of the number of active hydroxyl groups. Fluorescamine labelling of PU foams shows the colour change which could be [corrected] indicative of the presence of an amine, but the subsequent MALDI-MS analysis was unable to demonstrate the anticipated increase in mass. 相似文献
36.
C. Chan T. E. Drake R. Abegg D. Frekers O. H usser K. Hicks D. A. Hutcheon L. Lee C. A. Miller R. Schubank S. Yen 《Nuclear Physics A》1990,510(4):713-730
The complete set of Wolfenstein parameters, the polarization, the asymmetry of scattering and the unpolarized double-differential cross section are presented for inclusive quasielastic proton scattering from 12C at a central momentum transfer of q = 1.9 fm−1 and incident energies of 290 and 420 MeV. The spin observables D0, Dx, Dy and Dz as well as the longitudinal-to-transverse ratio of spin-flip probabilities are extracted from the data. Across the quasielastic continuum, the experimental data is compared to the variations expected from a single-scattering Fermi-gas approximation using the free NN amplitudes. Medium effects are evident in the pronounced quenching of the polarization parameter relative to the free value. 相似文献
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39.
E. Bonvin R. Bopp L. J. Carroll A. J. Cass S. U. Chung M. Donnat P. A. Dorsaz M. E. Feliks L. Fluri J. N. Jackson M. N. Kienzle-Focacci J. G. Lynch M. Martin L. Mathys P. J. Negus L. Perini R. Poultney W. H. Range L. Rosselet S. W. Snow A. S. Thompson R. M. Turnbull M. Werlen WA -Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,41(4):591-598
A search for pairs of highp T prompt photons produced in hydrogen by a 280 GeV/c incidentπ - beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forp T >3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of α s is also presented. 相似文献
40.
M. Bonesini E. Bonvin R. Bopp L. J. Carroll A. J. Cass D. Cavalli G. Costa S. U. Chung M. Donnat P. A. Dorsaz M. Feliks J. R. Fischer L. Fluri F. Gianotti S. Jack J. N. Jackson M. N. Kienzle-Focacci J. G. Lynch L. Mandelli M. Martin L. Mathys A. Maxwell M. Mazzanti P. J. Negus S. Pensotti-Rancoita L. Perini D. Perrin R. W. Poultney W. H. Range L. Rosselet S. W. Snow A. S. Thompson R. M. Turnbull J. Wells M. Werlen WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,44(1):71-78
The structure of events associated with the production of direct photons in π? p, π+ p andpp reactions of 280 GeV/c has been studied using data from the WA 70 experiment at the CERN SPS. Results are presented on the distributions of the fractional momenta of the colliding partons and on the fragmentation of the recoil jet and a comparison is made with predictions using the structure functions of Duke and Owens in the Lund Monte Carlo with string fragmentation. 相似文献