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941.
F. D. Saccone C. E. Rodrí guez Torres F. H. S nchez O. Gutfleisch 《Physica B: Condensed Matter》2002,320(1-4):312-315
In the present work, a quantitative analysis of the phase compositions by Mössbauer effect spectroscopy of solid and conventional hydrogen disproportionated Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys was carried out. Significant amounts of intermediate borides t-Fe3B and Pr(Fe, Co)12B6 were detected after solid hydrogen disproportionation treatment in Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys, respectively. After conventional hydrogenation–disproportionation–desorption–recombination treatment these phases were not detected and in no case residual Pr2Fe14B-phase was found. It was observed that the amount of intermediate borides after disproportionation can be correlated with the degree of texture after recombination at various temperatures. 相似文献
942.
Slug velocity profiles in horizontal gas–liquid flow 总被引:1,自引:0,他引:1
V. Bertola 《Experiments in fluids》2002,32(6):722-727
943.
F. Sibel Salman Jayant R. Kalagnanam Sesh Murthy Andrew Davenport 《Journal of Heuristics》2002,8(2):215-239
For hard optimization problems, it is difficult to design heuristic algorithms which exhibit uniformly superior performance for all problem instances. As a result it becomes necessary to tailor the algorithms based on the problem instance. In this paper, we introduce the use of a cooperative problem solving team of heuristics that evolves algorithms for a given problem instance. The efficacy of this method is examined by solving six difficult instances of a bicriteria sparse multiple knapsack problem. Results indicate that such tailored algorithms uniformly improve solutions as compared to using predesigned heuristic algorithms. 相似文献
944.
We have investigated the low-lying collective states and electromagnetic transitions in 94Mo within the framework of the interacting boson model. The influence of model parameters on the energy levels and electromagnetic properties has been investigated. The analysis of the obtained results and the parameter values predict that the 23+state is the lowest mixed symmetry state with pure F = Fmax - 1 in this nucleus. The calculated results predicate that the 25+ (two-Q-phonon) mixed symmetry state is closed to the J = 2+ at 2.870 MeV in the experimental data, and the 2.965 MeV state is the lowest mixed symmetry with J = 3+. 相似文献
945.
946.
G. Moortgat-Pick H. Fraas 《The European Physical Journal C - Particles and Fields》2002,25(2):189-197
The consequences of CP and CPT invariance for production and subsequent decay of Dirac and Majorana fermions in polarized fermion-antifermion annihilation
are analytically studied. We derive general symmetry relations for the production spin density matrix and for the three-particle
decay matrices and obtain constraints for the polarization and the spin-spin correlations of Dirac and Majorana fermions.
We prove that only for Majorana fermions the energy and opening angle distribution factorizes exactly into contributions from
production and decay if CP is conserved.
Received: 6 November 2001 / Revised version: 23 April 2002 / Published online: 12 July 2002 相似文献
947.
A. F. Ivanov 《Ukrainian Mathematical Journal》1989,41(8):903-906
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 8, pp. 1054–1058, August, 1989. 相似文献
948.
949.
F. Vlker 《Optics & Laser Technology》1991,23(6):331-334
An alexandrite-laser rod was actively Q-switched in the transversal fundamental mode at λ = 758 nm with an double crystal KD*P Pockels cell. Pulse width, pulse energy and optical pulse delay (the build-up time of the photon field in the resonator) were measured as functions of pumping energy, rod temperature and reflectivity of the output coupling mirror. As the laser gain of alexandrite strongly depends on temperature, the pulse width and pulse energy were also investigated as functions of the temperature of the active material. A comparison of experimental data with theory was made. 相似文献
950.
Summary We report on neutron emission in palladium and titanium electrolitically charged with deuterium. The detection of neutrons
is observed after thermal treatment of the electrode. In the hypothesis that neutrons came from cold fusion processes, we
estimate a fusion rate as high as 1.3·10−21 fusions/deuteron pair/second. 相似文献