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971.
The paper considers the problem of constructing an efficient automatic procedure for reducing the block size in the block conjugate gradient method insuring that the resulting rate of convergence is comparable with that of the block conjugate gradient method with constant block size. The numerical results provided show that, independently of the type of distribution of the smallest eigenvalues of the preconditioned matrix, the procedure suggested always leads to a decrease of the arithmetic costs with respect to those of the block method with constant block size. Bibliography: 8 titles. 相似文献
972.
Ya. A. Éyubov 《International Applied Mechanics》1991,27(1):48-55
Azerbaidzhan Institute of Construction Engineering, Baku. Translated from Prikladnaya Mekhanika, Vol. 27, No. 1, pp. 55–64, January, 1991. 相似文献
973.
A. G. Khovanskii 《Proceedings of the Steklov Institute of Mathematics》2007,259(1):82-100
We discuss the problem of representability and nonrepresentability of algebraic functions by radicals. We show that the Riemann
surfaces of functions that are the inverses of Chebyshev polynomials are determined by their local behavior near branch points.
We find lower bounds on the degrees of equations to which sufficiently general algebraic functions can be reduced by radicals.
We also begin to classify rational functions of prime degree whose inverses are representable by radicals. 相似文献
974.
We discuss differential equations with nonlinear boundary conditions. We formulate sufficient conditions under which problems
with deviating arguments have quasisolutions or solutions. To obtain the results, we apply the method of monotone iterations. 相似文献
975.
A. I. Vinogradov 《Journal of Mathematical Sciences》2007,140(5):646-654
An estimate of the remainder in the spectral decomposition of the generalized ζ function is given, which is more precise than
the known ones. This paper is a continuation of a previous paper published in one of the preceding issues. Bibliography: 1
title.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 330, 2006, pp. 77–92. 相似文献
976.
A theorem on the existence of a G-representation and a differential-geometric criterion of the kinematic integrability for nonlinear differential equations
from the Λ2-G-classes is proved. Examples of zero-curvature representations and metrics for some equations of mathematical physics are
presented.
__________
Translated from Fundamental’naya i Prikladnaya Matematika (Fundamental and Applied Mathematics), Vol. 11, No. 1, Geometry,
2005. 相似文献
977.
978.
S. A. Shiryaev M. V. Atamanov M. I. Guseva Yu. V. Martynenko A. V. Mitin V. S. Mitin P. G. Moskovkin 《Technical Physics》2002,47(2):238-243
It is suggested to produce metal-carbon composite coatings by magnetron sputtering of mosaic cathodes, which are Group IV,
V, and VI metals. The mosaic structure of the cathode elements are computer-optimized for each of the metals. Reflection electron
diffraction studies show that the coatings have the amorphous or nanocrystalline structures, which are thermally stable. The
coatings offer specific physical properties, in particular, low friction factor and high hardness. 相似文献
979.
In this context, we introduce and investigate the properties of the nonlinear negative binomial state (the state which interpolates between the nonlinear coherent and the number states). Mainly we concentrate on the statistical properties for such state where we have discussed two different cases of squeezing phenomenon. The first case is the normal squeezing while the second is the amplitude squared squeezing, further the second order correlation function is also considered. Our discussion have been extended to include the quasi-probability distribution functions (W-Wigner and Q-functions). The quadrature distribution and the phase properties in Pegg-Barnett formalism besides the phase variances are considered. Examination of the resonance fluorescence against the present state is given (single atom and thermodynamic limit). It has been shown that the atomic inversion is sensitive to any variation in the nonlinear negative binomial number m. 相似文献
980.
The aim of this paper is to highlight the added value of the generalized Gouy phase shift introduced by Siegman. Although suited for optical systems study, including those more complex than free space, we note that it did not meet the use that it deserves so far. The analysis of the whole of the ideas and analytical approaches associated to the important concept of the Gouy phase proves its effectiveness.
Usually, the resonance condition is systematically built on the basis of the equivalent empty cavity. Unfortunately, this approach does not cover some of the useful parameters of the real resonator. By means of the generalized Gouy phase and the self-consistent complex parameter q, we derive here a new approach for the calculation of the resonance condition for the real cavity. Moreover, the use of the generalized Gouy phase clearly simplifies the study of resonators, while making it possible to avoid the use of the Huygens’ Fresnel integral. 相似文献