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排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
The oxidation of 2,3,5,6-tetrachloro--phenylenediamine with Cl2 or Br2 in CCl4 containing I2 affords unusual quinoniminium salts displaying remarkable chemical behaviour. 相似文献
992.
Roberto D. Galvão 《European Journal of Operational Research》1981,6(2):162-165
The p-median problem is a minisium network location problem that seeks to find the optimal location of p centres in a network. In the present paper a graph-theoretical bound is developed for the problem. This bound is based on shortest spanning trees and arborescences and other graphical properties of the problem. It is shown that the graph-theoretical bound dominates a bound based on shortest distances. 相似文献
993.
Carlos A. Aragão de Carvalho 《Nuclear Physics B》1977,119(3):401-412
We investigate a theory using Callan-Symanzik equations. Logarithmic corrections to trivial fixed-point behaviour are obtained. The theory is shown to correspond to a model for tri-critical phenomena in 3He4He mixtures. 相似文献
994.
995.
α-spectrometry using Si(Au) detectors has been performed with thin samples of 237Np; αγ bi-parametric coincidences have permitted an analysis and unfolding of the spectrum and give data about the level scheme. Direct and α-coincident γ-spectra have been measured using Ge(Li) and Si(Li) detectors, obtaining the characteristic electromagnetic transitions in 233Pa. Nine new γ-transitions are found, relative to the most recent compilation made by Ellis. In the level scheme, the existence of a level at 306.1 keV is confirmed. A level at 257.1 keV, previously suggested, is evidenced. The level at 300.5 keV is proposed as the component of the band, hence proposing the 306.1 keV level as the term of the band. 相似文献
996.
997.
The surface dipole barrier D of metals is calculated from experimental work functions and theoretical bulk chemical potentials obtained by the Augmented-Spherical-Waves method of Williams et al. Two independent linear relations between D and the electron density at the boundary of Wigner-Seitz cells are found for transition and non transition metals. An explanation for this difference is offered. 相似文献
998.
A simple theoretical model which assumes a linear increase with thorium concentration for the cerium 4? level with respect to the Fermi level can explain both the decrease of the superconducting temperature and the logarithmic slope of the Kondo resistivity in LaTh based alloys with cerium impurities. The model yields two different maxima for || and , the second one of which occurs when the resistivity minimum disappears, in very good agreement with experimental data. 相似文献
999.
L. Zem
o W. Drenckhahn A. Feigel E. Finckh K. Rüskamp P. Urbainsky M. Wangler 《Nuclear Physics A》1982,380(3):493-501
The yield of the 209Bi(d, γ)211g.s.Po and 211mPo (T1/2 = 25.2s) reaction was measured for deuteron energies Ed = 8–11.5 MeV. The reaction was identified by the -activities of the Po isotope. At Ed = 10.43 MeV, the (d, γ) cross section for the population of the ground state of 211Po is σg.s. = 16 ± 3 μb, the ratio relative to the cross section for the metastable state is σg.s./σm = 25.4 ± 0.9. These values and the yield curves were compared with calculations using a simple model for the population of the two states. In the excitation region E* = 15–19 MeV, the branching ratio of γ- to particle emission is nearly constant and has a value of about 0.4 × 10−4. 相似文献
1000.