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961.
V. A. Harutyunyan S. L. Harutyunyan G. H. Demirjan N. H. Gasparyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2008,43(5):218-225
In the effective-mass approximation the single-electron states in a semiconductor cylindrical nanolayer in the regime of strong quantization are considered. The explicit form of the energy spectrum and envelope wave functions of single-electron states is obtained in the case of large and moderate radii of the system. The corresponding absorption bands of dipole and quadrupole optical transitions in the layer are calculated. 相似文献
962.
V. V. Kurta 《Mathematical Notes》1999,65(4):462-469
The main result of the paper is the nonexistence of integer positive solutions in wide classes of quasilinear elliptic equations
whose model examples are equations of the form {
}, where α>1 andq are some fixed real numbers.
Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 552–561, April, 1999. 相似文献
963.
S. V. Astashkin 《Mathematical Notes》1999,65(4):407-417
In this paper it is proved that from any uniformly bounded orthonormal system {f
n}
n=1
∞
of random variables defined on the probability space (Ω, ε, P), one can extract a subsystem {fni}
i
Emphasis>=1/∞
majorized in distribution by the Rademacher system on [0, 1]. This means that {
}, whereC>0 is independent of m∈N, ai∈N (i=1,…,m) andz>0.
Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 483–495, April, 1999. 相似文献
964.
Real valued M-estimators
in a statistical model 1 with observations
are replaced by
-valued M-estimators
in a new model with observations
where
are regressors,
is a structural parameter and
a structural function of the new model. Sufficient conditions for the consistency of
are derived, motivated by the sufficiency conditions for the simpler parent estimator
The result is a general method of consistent estimation in a class of nonlinear (pseudolinear) statistical problems. If F
has a natural exponential density ex–b( x ) then our pseudolinear model with u = (g o )–1 reduces to the well known generalized linear model, provided () = db()/d and g is the so-called link function of the generalized linear model. General results are illustrated for special pairs and leading to some classical M-estimators of mathematical statistics, as well as to a new class of generalized -quantile estimators. 相似文献
965.
Zeng Guangxing 《中国科学A辑(英文版)》1999,42(3):272-280
For an ordered field (K,T) and an idealI of the polynomial ring
, the construction of the generalized real radical
ofI is investigated. When (K,T) satisfies some computational requirements, a method of computing
is presented.
Project supported by the National Natural Science Foundation of China (Grant No. 19661002) and the Climbing Project. 相似文献
966.
广义对角占优阵的一个等价条件 总被引:2,自引:0,他引:2
郑秉文 《纯粹数学与应用数学》1999,15(2):37-41
给出了实方阵为广义对角占优阵的充要条件,同时给出了判断广义对角占优阵可靠,可行,较简单方法。 相似文献
967.
M. Keil T. Kolling K. Bergmann W. Meyer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(1):55-64
The process of dissociative attachment (DA) of low-energy electrons ) to vibrationally excited sodium dimer molecules is studied with high electron energy resolution () in a supersonic molecular beam. A novel photoelectron source, based on two-step photoionization of the sodium atoms in the
beam, may deliver a current of up to 1 nA and has been used with a current of typically 0.2 nA in this experiment. The energy
dependence of the rate of sodium anion formation is determined by ion detection based on a time-of-flight analysis. The molecules
are selectively excited to levels using the technique of coherent population transfer by delayed pulses (STIRAP). The comparison of the experimental data with
recent resonance model calculations based on improved potential curves reveals generally good agreement for levels v
”>12. For some distinct differences between theoretical and experimental results persist.
Received: 21 November 1998 / Received in final form: 7 April 1999 相似文献
968.
Let be a Jacobi matrix defined in as , where is a unilateral weighted shift with nonzero weights such that Define the seqences: If and , then has an absolutely continuous spectrum covering . Moreover, the asymptotics of the solution is also given.
969.
Let be an algebraic number field. Let be a root of a polynomial which is solvable by radicals. Let be the splitting field of over . Let be a natural number divisible by the discriminant of the maximal abelian subextension of , as well as the exponent of , the Galois group of over . We show that an optimal nested radical with roots of unity for can be effectively constructed from the derived series of the solvable Galois group of over .
970.
Irregular sampling, Toeplitz matrices, and the approximation of entire functions of exponential type
In many applications one seeks to recover an entire function of exponential type from its non-uniformly spaced samples. Whereas the mathematical theory usually addresses the question of when such a function in can be recovered, numerical methods operate with a finite-dimensional model. The numerical reconstruction or approximation of the original function amounts to the solution of a large linear system. We show that the solutions of a particularly efficient discrete model in which the data are fit by trigonometric polynomials converge to the solution of the original infinite-dimensional reconstruction problem. This legitimatizes the numerical computations and explains why the algorithms employed produce reasonable results. The main mathematical result is a new type of approximation theorem for entire functions of exponential type from a finite number of values. From another point of view our approach provides a new method for proving sampling theorems.