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1.
N. S. Simonović 《Few-Body Systems》2006,38(2-4):139-145
In agreement with the Kohn theorem the relative motion (rel) of three electrons in a two-dimensional parabolic trap separates
from the centre-of-mass (CM) motion. By introducing new coordinates the Hamiltonian for relative motion in the approximation
of non-interacting electrons can be taken to the normal form. The eigenstates of the normalized Hamiltonian are products of
the Fock-Darwin states for normal modes. The energy levels for relative motion are obtained by diagonalizing the exact Hamiltonian
in the eigenbasis for the non-interacting case. In this basis the interaction matrix elements can be obtained in the analytical
form. Since the rank of the Hamiltonian matrix is significantly reduced, the calculations are faster and more accurate than
those for the full (CM + rel) motion. This advantage is especially important for the calculations of excited states and the
analysis of energy spectra. 相似文献
2.
V. Čápek 《Czechoslovak Journal of Physics》1991,41(10):975-989
A review of ideas leading to full rejection of any finite or partially-infinite order kinetic equation linearized in external field is given on grounds of the time-convolution Generalized Master Equations (GME). By two examples (two-level and band conduction problem), it is shown how standard kinetic equations result from GME in the lowest order approximations which obscure, however, a direct correspondence with the Kubo linear response theory. Without approximations, on the other hand, the rigorous approach is shown to be fully equivalent with the Kubo results. It is argued and illustrated that usual technical simplicity and seeming physical lucidity of standard theories (connected with the presence of field-independent transfer or scattering rates in the fielddependent linearized theory) are just owing to structural features which are solely due to the lowest order approximations involved. These features (i.e. also the possibility of standard physical interpretation of kinetic phenomena) are proved to disappear completely as far as the theory goes properly to higher orders. 相似文献
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4.
In this paper a new definition of a lattice valued intuitionistic fuzzy set (LIFS) is introduced, in an attempt to overcome
the disadvantages of earlier definitions. Some properties of this kind of fuzzy sets and their basic operations are given.
The theorem of synthesis is proved: For every two families of subsets of a set satisfying certain conditions, there is an
lattice valued intuitionistic fuzzy set for which these are families of level sets.
The research supported by Serbian Ministry of Science and Technology, Grant No. 1227. 相似文献
5.
S. Mentus Dijana Jelić Veselinka Grudić 《Journal of Thermal Analysis and Calorimetry》2007,90(2):393-397
Thermal decomposition of lanthanum nitrate to lanthanum oxide was carried out by both temperature programmed heating (TPH)
and citrate-gel combustion. The temperature programmed heating was carried out under flow of oxidizing (air), neutral (nitrogen)
and reducing (25 vol.% hydrogen+argone mixture) gases, and the processes were controlled by simultaneous thermogravimetry
and differential thermal analysis. It was shown that hydrogen atmosphere helps to reduce temperatures of all decomposition
steps. The results of TPH were utilized to check the nature of residues in the products of lanthanum nitrate-to-oxide conversion
performed via citrate-gel combustion technique. 相似文献
6.
The purpose of this paper is two-fold. First, we introduce a new asymptotic expansion in the exponent for the compound binomial
approximation of the generalized Poisson binomial distribution. The dependence of its accuracy on the symmetry and shifting
of distributions is investigated. Second, for compound binomial and compound Poisson distributions, we present new smoothness
estimates, some of which contain explicit constants. Finally, the ideas used in this paper enable us to prove new precise
bounds in the compound Poisson approximation.
Published in Lietuvos Matematikos Rinkinys, Vol. 46, No. 1, pp. 67–110, January–March, 2006. 相似文献
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9.
Marijana ?aković Zora Popović 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):m507-m509
In the title compound, [Ni(N3)2(C6H6N2O)2], the NiII atom lies on an inversion centre. The distorted octahedral nickel(II) coordination environment contains two planar trans-related N,O-chelating picolinamide ligands in one plane and two monodentate azide ligands perpendicular to this plane. Molecules are linked into a three-dimensional framework by N—H...N hydrogen bonds. 相似文献
10.