Vol 17, No 8 (2011)
- Year: 2011
- Articles: 25
- URL: https://journals.ssau.ru/est/issue/view/232
Articles
N-ORDER MOMENT FUNCTION FOR THE SOLUTION OF THE CAUCHY PROBLEM FOR DIFFUSION EQUATION WITH RANDOM COEFFICIENTS
Abstract
Formula for n-order moment function for the solution of the Cauchy problem for three-dimensional diffusion equation with random coefficients and random initial condition is derived.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):5-20
5-20
SMOOTH APPROXIMATION FOR THE SOLUTIONS OF ELLIPTIC SYSTEMS
Abstract
The paper is devoted to the problem of piecewise-linear approximation of mapping for the elliptic system of solutions defined on triangular grids. A mapping is build to approximate the differential, and the estimate of error of approximation that does not depend on the degree of degeneracy of triangles of the grid. An analogous estimate is obtained for mappings which approximate the differential of solution of Beltrami equation.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):21-28
21-28
A MIXED PROBLEM WITH INTEGRAL CONDITION FOR A DEGENERATIVE EQUATION OF THE HYPERBOLIC TYPE
Abstract
In this article, the mixed problem for the hyperbolic degenerate equation with an integral condition is considered. The existence and uniqueness of a generalized solution are proved.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):29-36
29-36
THE SYSTEM OF SHIFTS OF FUNCTIONS
Abstract
The system of shift of functions in L2 (R) space is considered in this paper. We find conditions on real sequence g(x), which provide such properties of the system as to be a frame, Bessel system, complete sequence in the space L2 (R).
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):37-44
37-44
NUMERICAL METHOD OF AN EVALUATION OF LIMITS OF MAXIMAL MEANS FOR PERIODIC FUNCTIONS
Abstract
The method of approximate calculation of limit of maximal mean for periodic function depending on the time and basic variables and differential inclusion with a constant right hand is offered.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):45-49
45-49
FOURIER VECTOR TRANSFORMATION WITH DISCONTINUOUS COEFFICIENTS IN THE THEORY OF ELASTICITY
Abstract
The article deals with the description of the method of Fourier vector transformation with discontinuous coefficients. The dynamics of the theory of elasticity illustrates the technique of method in solving problems of mathematical physics of heterogeneous media.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):50-58
50-58
L-STABLE (4,2)-METHOD OF THE FOURTH ORDER FOR SOLVING STIFF PROBLEMS
Abstract
(M,k)-methods for solving stiff problems, in which on each step two times the right-hand side of the system of differential equations is calculated are investigated. It is shown that the maximum order of accuracy of the L-stable (m,2)-method is equal to four. (4,2)-method of maximal order is built.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):59-68
59-68
LIMIT THEOREM FOR INDEPENDENCE TRANSFORMATIONS COPULAS OF STUDENT'S t-DISTRIBUTION
Abstract
In the paper we study copulas obtained as a result of independence transformation of random vectors with Student's t-distribution. For the triangular scheme of dependent r.v. connected by such IT-copulas central limit theorem is proved. In addition, it is shown that two-dimensional IT-copula of Cauchy distribution is not associated.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):69-85
69-85
LOCAL SOLVABILITY OF SOME PROBLEM WITH FREE BORDER
Abstract
A certain single-phase problem with free border is studied. The local solvability of such problem is proved. The more general method investigated earlier is used in concrete event in this work.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):86-94
86-94
INITIAL-BOUNDARY VALUE PROBLEM FOR ONE-DIMENSION HYPERBOLIC EQUATION WITH INTEGRAL BOUNDARY CONDITION
Abstract
In this paper, we study an initial-boundary value problem with nonlocal integral condition for a hyperbolic equation. The existence and uniqueness of a generalized solution of the problem is proved.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):95-101
95-101
A PROBLEM WITH DISPLACEMENTS IN THE BOUNDARY CONDITIONS
Abstract
A problem with conditions relating to the values of an unknown function on the opposite sides of a rectangular characteristiс domain D for a linear hyperbolic equations is considered. This problem is reduced to the system of Fredholm equations of the second kind. The proof of solvability is based on the a priori estimates of additional conditions on the coefficients of the equation.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):102-107
102-107
NONLOCAL PROBLEMS FOR THE EQUATION OF THE MIXED PARABOLIC-HYPERBOLIC TYPE
Abstract
Boundary value problems with non-local conditions for partial differential equation are considered. In these problems, non-local conditions connect the values of a required solutions on the opposite sides of a rectangular domain. Criteria of uniqueness of each of the problems are obtained. Solutions to both problems are constructed as sums of Fourier series. The stability of solutions is proved.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):108-117
108-117
MODELING OF DOUBLY PERIODIC SYSTEM OF PRODUCING WELLS. 2. PRODUCTIVITY INDEX
Abstract
The question of productivity of doubly periodic systems of production wells is considered. Using the idealized production regime with a constant flow rate the analytical representation for the productivity index (PI) of the well was obtained and values depending on the drainage shapes were analyzed. Also an analytic representation for the Dietz's shape factor, which agrees with numerical calculations by the method of imaginary producing wells was obtained.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):118-127
118-127
A RECTANGULAR PLATE ON A TWO-PARAMETER ELASTIC BASE: THE ANALYTICAL SOLUTION
Abstract
In the paper the approximate solution for a problem of a rectangular plate on a two-parameter elastic base is suggested. The double series of beam functions satisfying elastic support boundary conditions are constructed. The analytical expressions for series function coefficients are obtained.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):128-133
128-133
FILM EVAPORATION FLOWING ON THE WALL OF THE VERTICAL PLANE CHANNEL
Abstract
This paper presents a mathematical model of a film evaporation of a liquid flowing downward by gravity on the wall of the vertical plane channel.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):134-141
134-141
THE COMPELLED AXISYMMETRIC BENDING FLUCTUATIONS OF THICK ROUND RIGID PLATE
Abstract
The new closed solution of axially symmetric nonstationary problem of the theory of elasticity for thick round anisotropic plate with rigid of its external radial surface is constructed. Calculated relations are obtained by method of expansion in eigen vector-functions in the form of structural algorithm of finite transformations. Numerical results allow to define the natural-vibration frequency, and also the stress-strain state of the testing element.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):142-152
142-152
THE INFLUENCE OF DIPOLE-DIPOLE INTERACTION ON THE ENTANGLEMENT FOR MANY-PHOTON TAVIS — CUMMINGS MODEL
Abstract
The influence of dipole-dipole interaction on the entanglement between two atoms and field in many-photon Tavis — Cummings with coherent cavity mode has been investigated. The results show that in the case of one-photon model the dipole-dipole interaction leads to the stabilization of atom-field entanglement.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):153-156
153-156
DENS-PHORESIS — A RATIONAL WAY OF USING MEDICAL MUD IN THE TREATMENT OF OSTEOARTHRITIS OF THE KNEE JOINT
Abstract
A new method of administering pharmaceutical substances with the help of apparatuses for dynamic electroneurostimulation (DENS) was suggested. This method is available in home conditions, preventoriums, social centers for communication and health. The article sets forth the results of experimental works on electrophoresis of medical mud with the help of the DENS apparatuses in patient with deforming osteoarthritis of the knee joint. The possibility of effective reduction of pain syndrome intensity in patients with osteoarthritis of II-III degrees was shown.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):157-162
157-162
METHODS OF OBTAINING STRONTIUM AZIDE
Abstract
In this paper all the ordinary ways of obtaining strontium azide are discussed. A new and more appropriate method of obtaining strontium azide from sodium azide is introduced. The most effective conditions of this method are described.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):163-166
163-166
PHARMACOLOGICAL ACTIVITY OF A PYRIMIDINE DERIVATIVES
Abstract
The main directions of the search of biologically active compounds, pyrimi-dine derivatives are described.The synthesis of pyrimidines with anticancer, antimicrobial, antiviral activity is shown as the most frequent in recent years. The examples of compounds are given, which are already being used in medicine practice or may be good starting points for obtaining new drugs.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):167-172
167-172
HEAVY METALS IN SOIL COVER OF ULIANOVSK CITY CHILDREN PARK
Abstract
The features of heavy metals content and lateral distribution of heavy metals in soil cover of Ulianovsk city children park are described in the article. The possible sources of polymetallic territory pollution are discussed.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):173-178
173-178
INFLUENCE OF DEFICIENCY OF CALCIUM AND MAGNESIUM ON MAINTENANCE OF PEPTIDE CONNECTIONS IN HUMAN ERYTHROCYTES AT THE INCUBATION IN VITRO
Abstract
The maintenance of peptide connections inside red blood cells and in the incubatory environment in the conditions of presence and absence of ions of calcium and magnesium, action of 1,3-dimetilksantin and АТГ is studied. The increase in the maintenance of peptides inside erythrocytes in the conditions of blocking L-calcium of channels and АТГ and reduction of their maintenance in the incubatory environment which is not containing ions of calcium is revealed.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):179-182
179-182
SOME MATERIALS ABOUT FEATURES OF STRUCTURE OF BIOLOGICAL GROUPS OF PLANTS IN THE AFFORESTATIONS SERVING AS HABITATS OF CONVALLARIA MAJALIS L
Abstract
The floristic structure of the investigated afforestations with participation of Convallaria majalis L. is considered. The rare species of plants growing together with Convallaria majalis L. are established. Potential stocks of medicinal raw materials of cenopopulations of Convallaria majalis L. in various afforestations are defined.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):183-195
183-195
ANATOMO-HISTOLOGICAL RESEARCH OF LEAFLETS OF DIFFICULT SHEET HEDYSARUM GRANDIFLORUM PALL
Abstract
There were studied microscopical constitution features of the compound leaf leaflets of a large-flowered tick trefoil Hedysarum grandiflorum Pall. that was gathered in Kinel district of the Samara region, in 2,5 km to the south - east from the village of Preobrazhenka, in June, 2009. The result of the survey helped to confirm, specify and enlarge information about morphological and histological characteristics of the leaflet of a compound leaf one of the genus Hedysarum family.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):196-201
196-201
LIVER FAT DYNAMICS OF AMUR SLEEPER PERCCOTTUS GLENII DYBOWSKI, 1877
Abstract
According to the materials received in 2007 and 2009 years, the data on liver fat reserve dynamics of Amur sleeper in concordance with their age, sex and maturity stage throughout the vegetation period is given.
Vestnik Samarskogo universiteta. Estestvennonauchnaya seriya / Vestnik of Samara University. Natural Science Series. 2011;17(8):202-205
202-205