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排序方式: 共有783条查询结果,搜索用时 46 毫秒
41.
M. Convery W. L. Davis K. DelSignore T. L. Jenkins E. Kangas M. Knepley K. L. Kowalski C. C. Taylor C. H. Wang S. H. Oh W. D. Walker P. L. Colestock B. Hanna M. A. Martens J. M. Streets R. C. Ball H. R. Gustafson L. W. Jones M. J. Longo J. D. Bjorken N. Morgan C. Pruneau 《Il Nuovo Cimento C》1996,19(6):1045-1049
Summary A small experiment, ?MiniMax?, has been set up in the C0 intersection region of the Fermilab Tevatron to seek evidence for
disoriented chiral condensates and to study other forward physics phenomena. The experiment consists of a proportional wire
chamber telescope accompanied by scintillation (trigger) counters, a lead converter, and followed by an electromagnetic calorimeter.
The solid angle accepted is a cone centered at pseudorapidity (η) of 4.1 and of radius (in η-ϕ space) of about 0.6. Over 2.5
million events thus far have demonstrated the successful operation of the apparatus, however to date the analysis has not
progressed sufficiently to permit any conclusions concerning disoriented chiral condensates.
presented byL. W. Jones
Paper presented at the Special Session on very high-energy cosmic-ray interactions (superfamilies) of the XXIV International
Cosmic-Ray Conference, Rome, August 28–September 8, 1995. 相似文献
42.
A detailed study of the gas chromatography of the aluminium(III), chromium(III) and iron(III) beta-diketonates has shown that their elution and separation characteristics arise from a number of adsorptive effects. Conditions of optimal peak shape for individual compounds are established by varying Chromatographie parameters, and the adsorption of one metal chelate on a column and its subsequent displacement by another chelate are investigated. The chromatography of iron(III) beta-diketonates is seen to be further complicated by gradual elution of a portion of the chelate before the rest of the sample. 相似文献
43.
E.W. Duck D. Grant J.R. Horder D.K. Jenkins A.E. Marlow S.R. Wallis A.G. Doughty J.M. Marandon G.A. Skinner 《European Polymer Journal》1974,10(6):481-488
VOCl3-Et3Al2C13(chlorinated activator) catalysts have been employed for the polymerization of ethylene at T between 15 and 85° in n-hexane. Using butylperchlorocrotonate as the activator, the following catalyst efficiencies (g polymerization, hr, atmosphere ethylene in the cap gas) were achieved: 106,1 MFI = 0-00; 105,8, e.g. MFI = 1 0 (with 9 per cent H2 present in the cap gas) and 106–9 MFI = 0?4 (with 44 mmole/1 styrene in the hexane medium). Reactions between the aluminium alkyl and the activator molecules produced other chlorinated species of high average activator effectiveness. The catalyst system could be reactivated by further additions of Et3Al2Cl3. The minimum value of the polymerization propagation rate constant is estimated to be 10122?6x10,461 cm3/mole sec. 相似文献
44.
45.
Matsukevich DN Chanelière T Bhattacharya M Lan SY Jenkins SD Kennedy TA Kuzmich A 《Physical review letters》2005,95(4):040405
We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After a programmable delay, the atomic excitation is converted into a photon (idler). Polarization states of both the signal and the idler are recorded and are found to be in violation of the Bell inequality. Atomic coherence times exceeding several microseconds are achieved by switching off all the trapping fields--including the quadrupole magnetic field of the magneto-optical trap--and zeroing out the residual ambient magnetic field. 相似文献
46.
Seweryniak D Woods PJ Carpenter MP Davinson T Janssens RV Jenkins DG Lauritsen T Lister CJ Ruiz C Shergur J Sinha S Woehr A 《Physical review letters》2005,94(3):032501
The level structure of (22)Mg has been studied with high-sensitivity gamma-ray spectroscopy techniques. A complete level scheme is derived incorporating all subthreshold states and all levels in the energy region relevant for novae burning. The excitation energy of the most important astrophysical resonance is measured with improved accuracy and found to differ from previous values. Combining the present result with a recent resonance energy measurement of this state leads to a derived (22)Mg mass excess of -400.5(13) keV. 相似文献
47.
Valiente-Dobón JJ Steinhardt T Svensson CE Afanasjev AV Ragnarsson I Andreoiu C Austin RA Carpenter MP Dashdorj D de Angelis G Dönau F Eberth J Farnea E Freeman SJ Gadea A Garrett PE Görgen A Grinyer GF Hyland B Jenkins D Johnston-Theasby F Joshi P Jungclaus A Lieb KP Macchiavelli AO Moore EF Mukherjee G Napoli DR Phillips AA Plettner C Reviol W Sarantites D Schnare H Schumaker MA Schwengner R Seweryniak D Smith MB Stefanescu I Thelen O Wadsworth R 《Physical review letters》2005,95(23):232501
Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max). 相似文献
48.
Jenkins SD Salerno D Minardi S Tamosauskas G Kennedy TA Di Trapani P 《Physical review letters》2005,95(20):203902
The spectra of chi(2) spatial solitons are measured close to the soliton-formation threshold and show the presence of sidebands, shifted by 39 THz from the laser line. By comparing with the predictions of a quantum optical field model, solved numerically in the full (3 + 1)-dimensional space, it is claimed that the observed temporal instability of the spatial soliton is seeded by vacuum state fluctuations of the electromagnetic field. 相似文献
49.
NO reduction on the noble metal Ag has been studied using density functional theory calculations. It was found that monomeric NO dissociation is subject to prohibitive barriers on Ag metal and is thus unlikely to account for the experimental observations for NO reduction over Ag-based catalysts. For the first time, a mechanism via an inverted (NO)(2) dimer is identified, which can explain both the high activity and the selectivity of this catalytic system. N(2)O is the major reduction product of the inverted (NO)(2) dimer, in accord with experiment. The physical origin of the Ag metallic state as a good catalyst is furthermore identified: Ag surfaces, including small clusters, have little or no covalent bonding ability but can bond ionically with adsorbates. We conclude that the variation of the ionic bonding strength of Ag toward different reactants determines its catalytic selectivity. 相似文献
50.
Jenkins MA 《Electrophoresis》2004,25(10-11):1555-1560
Using capillary electrophoresis (CE) for serum protein electrophoresis, the quality of results begins with monitoring a well-functioning instrument, using scrupulously clean capillaries, well-calibrated methods as well as regular use of an internal quality control material. Quality assurance programs are available in countries such as Australia, United Kingdom, United States, and European countries such as Sweden and Germany. The present commercial control material that is available gives percentages of albumin, alpha 1, alpha 2, beta- and gamma-globulins, the gamma-component being of normal distribution, and not containing any monoclonal protein component. We feel that a quantitative commercial control material containing a monoclonal protein at decision level for treating myeloma patients would be beneficial to all laboratories as a serum protein electrophoresis control, whether the analysis is by CE or agarose gels. The same applies for control material for urinary protein electrophoresis. 相似文献