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931.
932.
M. Liang H. Ohm B. De Sutter K. Sistemich 《Zeitschrift für Physik A Hadrons and Nuclei》1992,344(3):357-358
Tie half-lives of 8 low lying levels of103Nb have been determined at the fission-product separator JOSEF. A B-- triple-coincidence method was used which consists in a measurement of the time delay between the feeding of the levels through the B– decay of103Zr and their decay, in coincidence with a tagging ray, with plastic, BaF2 and Ge detectors, respectively. Most of the investigated levels are members of the three known rotational bands based on the ground state and the 164 and 248 keV levels. The deformation Bq=0.31(3) of103Nb could be deduced from the half-life data. The half-lives are well reproduced through calculations in the frame of the Nilsson model.The authors thank Dr. T. Seo for valuable advise in connection with the Nilsson-model calculations. 相似文献
933.
934.
M. Liang H. Ohm B. De Sutter K. Sistemich B. Fazekas G. Molnär 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(2):223-224
The half-lives of low-lying levels of the neutron-rich isotopes102Mo and104Mo have been measured at the fission product separator Josef with the ß-- triple coincidence technique. Values of t1/2= 126(4)ps and 0.72(4)ns have been obtained for the 21
+ levels at 296 keV and 192 keV in102Mo and104Mo, respectively. Deformation parameters of ßq=0.28(1) and 0.31(1), respectively, are deduced, which are smaller than those of the isotones of Sr and Zr. The interacting boson model accounts well for the trend of 2+ energies in the Mo isotopes but slightly overpredicts the B(E2) values at saturation. A smooth dependence of 21
+ vs. E 21
+ is found for the A 100 region in agreement with the hydrodynamical model.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献
935.
We present a multipass femtosecond amplifier pumped by a Nd-YAG laser where the gain medium is given by a variable length dye cell. This system allows amplification factors up to 5 · 106 and output pulse energies of 150 J, while restricting the contribution of amplified spontaneous emission to 0.5% of the total output energy, without using any saturable absorber stage. A detailed study of the output pulsewidth as a function of the duration of the input chirped pulse is also presented. 相似文献
936.
937.
The kinetics of substitution of aqua ligands fromcis-[Ru(bipy)2(H2O)2]2+ ion by salicylhydroxamic acid (L) in aqueous medium has been studied spectrophotometrically at different temperatures (50–65°C).
The following rate law has been established in the pH range 4.0 to 5.8;
相似文献
938.
Antonio Maschietti 《Journal of Geometry》1992,44(1-2):107-116
In this paper, we investigatec-sets in 2-designs, with particular regard to sets of type (0,n) in projective planes. In particular, we associate a Hadamard design to a hyperoval of a projective plane of even orderq and we investigate some properties of its lines. This gives information on the order of the projective plane. 相似文献
939.
J. Demaret Y. De Rop P. Tombal A. Moussiaux 《General Relativity and Gravitation》1992,24(11):1169-1183
The Einstein-like field equations obtained from the variation of a Lagrangian containing linear, quadratic (Gauss-Bonnet) and quartic terms for a ten-dimensional cosmological model cannot be solved analytically. However, we can reduce them to a system of dynamical equations for the Hubble parameters. The study of the mathematical properties of the fixed points of this system gives a qualitative picture of the behaviour of a class of possible solutions. The inclusion of a quartic term generates an extremely rich structure for the corresponding dynamical system. Some solutions are shown to exhibit the interesting property of dimensional reduction, which has been proposed as a possible explanation of the three-dimensional character of our universe. 相似文献
940.
We study the Boltzmann-Grad limit in various versions of the two-dimensional HPP cellular automaton. In the completely deterministic case we prove convergence to an evolution that is not of kinetic type, a well-known phenomenon after Uchyiama's paper on the Broadwell gas, whereas the limiting equation becomes of kinetic type in the model with random collisions. The main part of the paper concerns the case where the collisions are deterministic and the randomness comes from inserting, between any two successive HPP updatings,
- stirring updatings, <1 being any fixed positive number and a parameter which tends to 0. The initial measure is a product measure with average occupation numbers of the order of (low-density limit) and varying on distances of the order of –1. The limit as 0 of the system evolved for times of the order of
-1- corresponds to the Boltzmann-Grad limit. We prove propagation of chaos and that the renormalized average occupation numbers (i.e., divided by) converge to the solution of the Broadwell equation. Convergence is proven at all times for which the solution of the Broadwell equation is bounded. 相似文献
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