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41.
A review and some new results are presented for several cluster statistics models, solutions of which can be reduced to difference equations. Mathematical techniques suitable for solving these equations are surveyed. 相似文献
42.
43.
F. Štěrba J. Lipták Nguyen An Ninh J. Štěrbová J. Starý 《Czechoslovak Journal of Physics》1988,38(7):741-754
Excitation functions for the55Mn(p, p )55Mn,55Mn(p, n )55Fe and55Mn(p, )56Fe reactions are studied for proton beam energyE
p=1·3–2 MeV. The excitation functions are established from yield functions for -rays emitted from the first excited states of final nuclei. Many resonances are observed and competition of their decay into all three output channels is analysed. Spin-parity assignment for some resonant states in the56Fe compound nucleus is deduced.Participated partly in the course of his work on a Thesis.The authors wish to thank the staff of the Van de Graaff accelerator at Charles University in Prague for the efficient operation of the machine and dr. I. Wilhelm for the valuable technical help in the early period of the experimental work. One of us (N. A. N.) acknowledges the staff of the Dept. of Nuclear Physics of Charles University in Prague for the excellent working conditions. 相似文献
44.
The4He(
,p)n cross section, vector and tensor analyzing-power data with 12 and 17 MeV deuterons at kinematic conditions including proton-alpha quasifree scattering, neutron-alpha and proton-alpha final-state interactions, as well as collinearity, are compared with the predictions of the three-body model using different nucleon-alpha and neutron-proton forces. In general, better two-body potentials give a better fit to the data, except for the vector analyzing-power data. The roles of the impulse and multiple-scattering amplitudes are studied to understand the sensitivity to two-body potentials and to understand the reason for the successes and the failures of the model. 相似文献
45.
We derive scaling forms for the thermodynamic and correlation quantities for the turn-weighted fully and partially directed self-avoiding walks on the hypercubic lattices ind2. In the grand canonical (fixed fugacity per step) ensemble, the conformational rod-to-coil transition sets up in the regimew¯N=O(1), wherew is the weight of each 90° turn and¯N is the (fugacity-dependent) average number of steps. Contrary to the conventional critical phenomena wisdom, the scaling functions for the two different walk models, directed and partially directed, become universal only in the limitd. 相似文献
46.
The time dependence of the electron distribution function in helium afterglow, for pressures of 60–260 Pa, is calculated for the case in which metastable-metastable reactions are present. The time variation of the shape of the distribution function shows that careful consideration must be made of the time derivative of the distribution function in the Boltzmann equation for the calculation of the rate constant of such reactions from experimentally determined distribution function. 相似文献
47.
We calculate the density of states for the nondegenerate Anderson model for various values ofu=U/ andn
f
using the perturbation theory withu as the expansion parameter. Summing all the -independent self-energy diagrams, we use the Friedel sum rule and Ward identities to express the physical quantities in terms of the remaining -dependent part of the self-energy, which we evaluate to the 2nd order. The results for the spin and charge susceptibilities obtained in such a way compare rather well with the Bethe-ansatz results. The density of states exhibits different features in different parts of the parameter space. In Kondo region (u>1,n
f
1, i.e., –
f
~U/2), we obtain a many-body resonance (half-width T
K
) around the Fermi level and two broad peaks () at about
f
+n
f
U and
f
+U. In the VF region (u>1, and |
f
|) we obtain only two peaks (), one at about
f
and one between
f
+n
f
U and
f
+U. The consequences regarding the shape of the photoemission and inverse photoemission spectra of Ce intermetallics are discussed. 相似文献
48.
Ladislav Špaček 《Czechoslovak Journal of Physics》1955,5(3):431-433
49.
Ivan Šolc 《Czechoslovak Journal of Physics》1955,5(1):80-86
, 4, (1954), 53. . . 相似文献
50.
J. Adam A. Kuklík A. Špalek D. Venos M. Ja. Kuznecova 《Czechoslovak Journal of Physics》1978,28(8):857-864
Gamma-radiation from the reactions of 28 MeV and 26 MeV3He-ions on the209Bi target has been studied by means of Ge(Li) detectors. Individual observed prompt -ray transitions have been assigned to the corresponding reactions. The results of previous studies of the209At nucleus have been verified and completed. Two new levels at energies of 640 keV and 1270·5 keV have been introduced. Additionally, 15 new transitions have been observed which could belong to209At. The209At level structure is discussed in terms of nuclear models. 相似文献