Количество страниц: 20 с.
We establish the necessary and sufficient conditions for the solution of the second-order parabolic equation in a stellar domain with a lateral boundary in the class degenerate on the boundary of the domain, to have an average limit on the lateral surface of the cylindrical domain and the limit in the mean on its lower base. Also, we study the unique solvability of the first mixed problem for such equations in the case when the boundary and initial functions belong to spaces of the type. The closest to the questions under consideration are the theorems of Riesz and Littlewood and Paley, in which criteria are given for the limit values in p > 1, of functions analytic in the unit disk. Further development of this topic for uniformly elliptic equations was obtained in the works V. P. Mikhailov and A. K. Gushchin. The boundary smoothness condition can be weakened, as was shown by I. M. Petrushko. Under the weakest restrictions on the smoothness of the boundary (and on the coefficients of the equation), the criteria for the existence of a boundary value were established in by A. K. Gushchin. In this case, all directions of the acceptance of boundary values for uniformly elliptic equations turn out to be equal, the solution has the property similar to the property of continuity with respect to the set of variables. In the case of degeneracy of the equation on the boundary of the domain, when the directions are not equal, the situation is more complicated. In this case, the formulation of the first boundary value problem is determined by the type of degeneracy. When the values of the corresponding quadratic form of the degenerate elliptic equation on the normal vector are different from zero (Tricomi type degeneracy), the Dirichlet problem is well-posed and the properties of such degenerate equations are very close to the properties of uniformly elliptic equations. In particular, in this situation analogues of the Riesz and Littlewood-Paley theorems are valid.
Капицына, Т. В. О существовании граничных и начальных значений для вырождающихся параболических уравнений в звездных областях / Т. В. Капицына // Математические заметки СВФУ. — 2018. — Т. 25, N 4 (100), октябрь-декабрь. — С. 15-33.
DOI: 10.25587/SVFU.2018.100.20551
Количество страниц: 16 с.
The article is devoted to studying one of the sections of nonclassical differential equations, namely, matters concerned with solvability of parabolic equations with changing second-order time direction. As is known, in ordinary boundary-value problems for strictly parabolic equations, the smoothness of the initial and boundary conditions completely ensures that the solutions belong to the Holder spaces, but in the case of equations with changing time direction, the smoothness of the initial and boundary conditions does not ensure that the solutions belong to these spaces. S.A. Tersenov (for a model parabolic equation with changing time direction) and S.G. Pyatkov (for a more general second-order equation) obtained the necessary and sufficient conditions for solvability of the corresponding mixed problems in Holder spaces. In so doing, they always assumed the initial and boundary conditions being equal to zero. Cases in which the initial and boundary conditions belong to Banach spaces are considered. The functional spaces in which the solutions must be sought are introduced. Relevant a priori estimates, which make it possible to obtain the solvability conditions for these problems, are obtained. The properties of the obtained solutions have been studied. In particular, the equivalence of the Riesz and Littlewood-Paley conditions similar to the conditions for solutions of strictly elliptic and strictly parabolic second order equations is established. A unique solvability of the first mixed problem with boundary and initial functions from the Banach space has been proved.
Петрушко, И. М. О первой смешанной задаче в банаховых пространствах для вырождающихся уравнений с меняющимся направлением времени / И. М. Петрушко, М. И. Петрушко // Математические заметки СВФУ. — 2018. — Т. 25, N 4 (100), октябрь-декабрь. — С. 45-59.
DOI: 10.25587/SVFU.2018.100.20553
Количество страниц: 14 с.
We study the class of test functions constructed on the principle of Lizorkin spaces by means of mixed Fourier-Kipriyanov-Katrakhov transform. Initially, such classes of functions, constructed on the basis of a mixed Fourier-Bessel transform, were investigated by L. N. Lyakhov. The spaces introduced by him could not take into account “odd” orders of singular derivatives. But the latter appeared to be fundamentally necessary in the problems of determining the fundamental solutions of differential equations (ordinary and in partial derivatives). The integral Kipriyanov-Katrakhov transform (belonging to the class of Bessel transforms) is adapted to work with singular differential operators of the type where k takes values 0 or 1, is a singular differential Bessel operator and the order of differentiation is 2m. The spaces of the basic functions that represent the images of the mixed Fourier-Kipriyanov-Katrakhov transform of functions vanishing at the origin and infinity are considered in this paper. We study the possibility of approximating functions from weighted Lebesgue classes with power weight namely, the density theorem in the Lebesgue function space.
Половинкина, М. В. О плотности специального класса функций Лизоркина в весовом лебеговом пространстве L (gamma) p / М. В. Половинкина, С. А. Рощупкин // Математические заметки СВФУ. — 2018. — Т. 25, N 4 (100), октябрь-декабрь. — С. 60-73.
DOI: 10.25587/SVFU.2018.100.20554
Количество страниц: 6 с.
- Математика. Естественные науки > Математика,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Математика,
- Прикладные науки. Медицина. Ветеринария. Техника. Сельское хозяйство > Инженерное дело. Техника в целом,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Физика,
- НАУКА ЯКУТИИ > ПРИКЛАДНЫЕ НАУКИ. МЕДИЦИНА. ТЕХНИКА. СЕЛЬСКОЕ ХОЗЯЙСТВО > Инженерное дело. Техника в целом.
This paper considers a mathematical model of joint laying of water pipeline networks and district heat networks. The purpose of the work is to study the effect of radiation on the process of complex heat exchange taking place in the housing insulation between structural elements. The results of mathematical simulation of the heat loss taking into account the radiant component are given. When calculating the heat flows which are lost in the pipeline through thermal insulation at transporting the coolant, the heat transfer process is usually considered by means of conduction and convection. The radiant component is neglected in most cases. The influence of heat transfer by radiation and convection is particularly noticeable using thermal insulation products with large pores and air gaps. A ground configuration of a pipe line and water pipe line laid in a joint thermal insulation made of mineral wool is considered. When laying joint pipelines, complex radiative heat transfer occurs. It consists, for each one of these pipelines, of radiation reflected from the other pipeline and self-radiation. A non-stationary temperature field of the structure, consisting of two parallel stacked pipes with different diameters lying in a joint insulating structure made of mineral wool, is calculated. The construction elements exchange heat with each other and the environment by convection and radiation.
Степанов, А. В. Оценка влияния лучистой составляющей на сложный теплообмен между сетевым трубопроводом и водопроводом при совместной прокладке / А. В. Степанова, Г. Н. Егорова // Наука и образование. — 2017. — N 4 (88), октябрь-декабрь. — С. 93-98.
Количество страниц: 12 с.
A mathematical model describing an equilibrium of cracked two-dimensional bodies with two mutually intersecting cracks is considered. One of these cracks is assumed to be straight, and the second one is described with the use of a smooth curve. Inequality type boundary conditions are imposed at the both cracks faces providing mutual non-penetration between crack faces. On the external boundary, homogeneous Dirichlet boundary conditions are imposed. We study a family of corresponding varia-tional problems which depends on the parameter describing the length of the straight crack and analyze the dependence of solutions on this parameter. Existence of the solution to the optimal control problem is proved. For this problem, the cost functional is defined by a Griffith-type functional, which characterizes a possibility of curvilinear crack propagation along the prescribed path. Meanwhile, the length parameter of the straight crack is chosen as a control parameter.
Лазарев, Н. П. Задача оптимального управления длиной поперечной трещины в модели равновесия двумерного тела с двумя пересекающимися трещинами / Н. П. Лазарев, Е. М. Рудой, Т. С. Попова // Математические заметки СВФУ. — 2018. — Т. 25, N 3 (99), июль-сентябрь. — С. 43-53.
DOI: 10.25587/SVFU.2018.99.16950
Количество страниц: 14 с.
We study existence of the left inverse, right inverse and inverse of Gaussian infinite matrices (those are the upper infinite triangular matrices with nonzero elements on the main diagonal). The existence of a unique inverse of the Gaussian matrix is proved. Also, an explicit expression for the inverse of the Gaussian matrix of any order is found, including the infinite case. Implementation of this expression is very convenient, since calculations are based on recurrence relations. Such approach can be extended to triangular infinite matrices (those are the lower infinite triangular matrices with nonzero elements on the main diagonal). Thus, there is the possibility of inversion of an infinite matrix of infinite rank, since such matrices decompose into the product of two matrices, a triangular and a Gaussian.
Об обращении бесконечных гауссовых матриц / Ф. М. Федоров. Н. Н. Павлов, С. В. Потапова, О. Ф. Иванова // Математические заметки СВФУ. — 2018. — Т. 25, N 3 (99), июль-сентябрь. — С. 54-67.
DOI: 10/25587/SVFU.2018.99.16951
Количество страниц: 16 с.
We study solvability of the inverse problems for finding both the solution u(x,t) and the coefficient q(x) in the equation d2m+iu (~l)m+1 dt2m+l +Ац + МЦ = f{x,t)+q{x)h{x,t), where x = (xi,...,xn) € fi, fi is a bounded domain in t € (0,T), 0 < T < +ro, f (x,t) and h(x,t) are given functions, p is a given real, m is a given natural, and A is the Laplace operator acting in spatial variables. As an additional condition (which is necessary due to presence of the additional unknown function q(x)), the boundary overdetermination condition is used in the article (with t = 0 or t = T). For the problems under study, the existence and uniqueness theorems for regular solutions are proved (all derivatives are the Sobolev generalized derivatives).
Акимова, Е. В. Линейные обратные задачи пространственного типа для квазипараболических уравнений / Е. В. Акимова, А. И. Кожанов // Математические заметки СВФУ. — 2018. — Т. 25, N 3 (99), июль-сентябрь. — С. 3-17.
DOI: 10.25587/SVFU.2018.99.16947
Количество страниц: 7 с.
We present a mathematical model of jigging using the statical approach for describing the process and the theory of Brownian motion. The Fokker-Planck equation is obtained for fractions in a jigging machine. The distributions of the grainy rocks under study are calculated in various cases.
Математическое моделирование процесса отсадки / Л. В. Никифорова, А. И. Матвеев, Е. С. Слепцова, Б. В. Яковлев. – Текст : непосредственный // Математические заметки СВФУ. – 2014. – Т. 21, N 1, январь-март. – C. 106-112.
Количество страниц: 8 с.
- Математика. Естественные науки > Математика,
- Прикладные науки. Медицина. Ветеринария. Техника. Сельское хозяйство > Инженерное дело. Техника в целом,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Математика,
- НАУКА ЯКУТИИ > ПРИКЛАДНЫЕ НАУКИ. МЕДИЦИНА. ТЕХНИКА. СЕЛЬСКОЕ ХОЗЯЙСТВО > Инженерное дело. Техника в целом.
In this paper theoretically discusses the motion of particles inside the screw air separator. At the initial stage auxiliary model is considered: particle motion along a conical surface with a given angle under the action of the axiales flow of air. In this case the normal to the surface of the cone has two components: vertical and radial. Model allows to find the law of motion of a particle along a conical surface. To get the screw surface sophisticate model, namely, the components of the surface normal axial add a third component. Then set up will describe the normal helical surface. As the working surface of the spiral air separator is chosen with a specific surface of angle and axial angles. The particle motion occurs only at the working surface. Knowing the law of motion of a single particle, we can determine the trajectory for the system of non-interacting particles. Thus, in a first approximation for non-interacting particles the particle concentration can be determined on a screw surface, as well as in the radial direction and in the vertical plane.
Моделирование движения частиц в винтовом пневмосепараторе / А. И. Матвеев, И. Ф. Лебедев, Л. В. Никифорова, Б. В. Яковлев // Горный информационно-аналитический бюллетень. – 2014. – N 10. – C. 172-178.
Formation of mathematical literacy of students
Количество страниц: 2 с.
- Общественные науки. Образование > Народное образование. Воспитание. Обучение. Организация досуга > Общеобразовательная школа. Дошкольные учреждения,
- Математика. Естественные науки > Математика,
- НАУКА ЯКУТИИ > ОБЩЕСТВЕННЫЕ НАУКИ > Народное образование. Воспитание. Обучение. Организация досуга > Общеобразовательная школа. Дошкольные учреждения,
- НАУКА ЯКУТИИ > МАТЕМАТИКА. ЕСТЕСТВЕННЫЕ НАУКИ > Математика.
Фефилова, Н. А. Формирование математической грамотности обучающихся / Н. А. Фефилова ; МОБУ "Гимназия п. Нижний Куранах" // Народное образование Якутии. - 2022. - N 1 (122). - С. 106-108.