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931.
Yu. I. Paskal' 《Russian Physics Journal》1988,31(8):664-666
Various meanings of the terms phase and phase transition encountered in scientific literature are discussed. These terms supplement each other and cover only together all the macroscopic situations which are now denoted by this term.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 67–71, August, 1988. 相似文献
932.
S. Yu. Orevkov 《Mathematical Notes》1990,47(1):82-88
Translated from Matematicheskie Zametki, Vol. 47, No. 1, pp. 127–136, January, 1990. 相似文献
933.
Yu. A. Aminov 《Journal of Mathematical Sciences》1990,48(1):1-5
In this article we prove that the principal direction fields are holonomic and use them to introduce curvilinear coordinates on an immersed region in terms of which the linear element of Lobachevskií space is written in the form
where
The fundamental system of equations is established for an immersion ofn-dimensional Lobachevskií space into 2n-dimensional Euclidean space withn principal direction fields for the functions
i and, and a way of constructing an arbitrary local analytic immersion is shown.Translated from Ukrainskií Geometricheskií Sbornik, No. 28, pp. 3–8, 1985. 相似文献
934.
Yu. P. Goncharov 《Letters in Mathematical Physics》1990,19(1):73-81
The possibility is discussed of generalizing the Polyakov approach to strings on membranes and the connection of such a generalization with Thurston's classification of three-dimensional geometries. The important ingredients for computing a membrane path integral are the determinants of scalar Laplacians acting in real line bundles over three-dimensional closed manifolds. In the closed bosonic membrane case, such determinants are evaluated for a class of closed 3-manifolds of the H
3/ form with a discrete subgroup of isometries of the three-dimensional Lobachevsky space H
3 and they are expressed in terms of the Selberg zeta function. Some further possible implications of the results obtained are also discussed. 相似文献
935.
Yu. M. Berezanskii B. Ya. Levin V. A. Marchenko Yu. A. Mitropol''skii I. V. Ostrovskii 《Functional Analysis and Its Applications》1990,24(2):85-85
Obituary
Mark Grigor'evich Krein 相似文献936.
One considers the differential equation dx/dt=f(t, x) with the impulse action ¦t=ti=Hi(ti,x) in the space of bounded numerical sequences, where f(t, x), Hi(t, x) are T-periodic, countable-dimensional vector-valued functions, is a positive parameter. One gives conditions for the existence of a control (1,2) such that the solution of the equation dx/dt=f(t, x)–1 with impulse action x¦t=ti=Hi(ti,x)–2 assuming for t= the value x=x0, be T-periodic.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 2, pp. 271–275, February, 1990. 相似文献
937.
The problem of estimating the rate of convergence in the central limit theorem for the U-statistics with values in the Hilbert space is considered. Bounds of the order o(n–1/2) if the kernel satisfies the nondegenerate condition and E3 < .Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 8, pp. 1043–1050, August, 1990. 相似文献
938.
Yu. I. Volkov 《Ukrainian Mathematical Journal》1990,42(7):785-796
The concept of the deformation of positive linear operators of type B is introduced, in particular, that of a linear deformation of operators. These concepts are applied to the solving of operator equations of type B. One solves completely the problems of the determination of all positive linear operators of type B for which the covariance of the operators is 1) a polynomial of degrees 3; 2) any power function; 3) an exponential function. In addition, one finds; two families of positive linear operators of type B for which the covariance is a polynomial of degree four.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 7, pp. 888–900, July, 1990. 相似文献
939.
An optimization problem of interactive inhomogenous flows (Steiner multicommodity network flow problem) is formulated. The problem's main characteristic is a fixed charge change when combining multicommodity communications. In this paper we propose a method for solving this problem which, in order to restrict the search on the feasible domain, reduces the original problem to a concave programming problem in the form: min {f(x)|xX} wheref:n is a concave function, andX
0
n
is a flow polytope defined by network transportation constraints. For practical large-scale problems arising from planning transportation networks on inhomogeneous surfaces defined by a digital model, a method of local optimization over a flow polytope vertex set is proposed, which is far more effective in comparison with the Gallo and Sodini method under polytope strong degeneracy conditions. 相似文献
940.
Results are presented from a study of electrical breakdown of anodic aluminum oxide in a constant field with a platinum pressure electrode. Statistical breakdown parameters and their dependence on the magnitude and polarity of the applied voltage are obtained. Field and temperature dependences of breakdown delay time over the interval 10–6–103 sec are determined. It is shown that the experimental (E) curves can be rectified (in two segments) in the coordinates log E–1. This indicates a possible contribution to the breakdown mechanism by both tunnel injection of electrons from the cathode and subsequent avalanche multiplication of electrons within the dielectric.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 25–29, April, 1990.In conclusion, the authors thank T. V. Shmidt and E. Ya. Khanin for assistance in the study. 相似文献