Herald of Kazakh-British technical university

ISSN

1998-6688

2959-8109

Ключевые слова

Differential Equation...

Advanced Topology and...

Enhanced Oil Recovery...

Nonlinear Differentia...

Reservoir Engineering...

Публикации в журнале

Показано: 1 - 5 из 5

Некоторые метрики заблокированы вашими
настройками согласия
NUMERICAL SOLUTION OF A BOUNDARY VALUE PROBLEM WITH A PARAMETER FOR IMPULSIVE LOADED DIFFERENTIAL EQUATIONS
(2024-07-01)
Zh. М. Каdirbayeva
;
Svetlana Temesheva
;
B. B. Мinglibayeva
;
N. M. Shaimerden
The boundary value problem depending on the parameter for the system of impulsive loaded differential equations is considered. Algorithms of numerical realization of the Dzhumabaev parameterization method are developed for numerical solving of the studied boundary value problem depending on the parameter. Algorithms of numerical realization of the Dzhumabaev parameterization method are based on the solving of Cauchy problems for the system of ordinary differential equations. As a result of application of the proposed method, finding a solution to the boundary value problem depending on the parameter for impulsive loaded differential equations leads to finding a solution to the system of algebraic equations. This system of algebraic equations consists of a boundary condition and equalities with respect to the conditions at the impulsive points. Numerical results showing the high efficiency of the numerical implementation of the Dzhumabaev parameterization method are given. The result demonstrate that there is congruence between the numerical and the exact results to a high order of accuracy.
Некоторые метрики заблокированы вашими
настройками согласия
NUMERICAL METHOD FOR SOLVING THE BOUNDARY VALUE PROBLEM FOR THE PARABOLIC EQUATION
(2024-10-01)
Narkesh B. Iskakova
;
Zh. М. Каdirbayeva
;
E. А. Bakirova
;
Saule Kuanysh
A linear boundary value problem for a parabolic equation is considered in a closed domain. Based on the broken line method, the boundary value problem for a parabolic equation is replaced by a two-point boundary value problem for a system of linear ordinary differential equations by discretizing the unknown function u(t,x) with respect to the variable x. The obtained two-point boundary value problem is investigated by the parameterization method of Professor Dzhumabaev. Based on this method, an algorithm for finding a numerical solution to the two-point boundary value problem for a system of linear ordinary differential equations is constructed. The constructed algorithm is realized by applying known numerical methods. The constructiveness and efficiency of the parameterization method also allows us to construct a numerical solution of the considered linear boundary value problem for the parabolic equation. One numerical example is given to verify and illustrate the proposed algorithm.
Некоторые метрики заблокированы вашими
настройками согласия
COMPARATIVE ANALYSIS OF X-RAY LUMINOSITY OF PERSISTENT AND TRANSIENT HIGH-MASS X-RAY BINARIES
(2026-03-29)
Zhantay Muratkhan
;
Manas Khassanov
;
Aray Muratkhan
;
Aliya Taukenova
;
A. Sadu
High-mass X-ray binaries (HMXBs) are commonly divided into persistent sources, which emit X-rays steadily over long periods, and transient sources, which remain mostly in a quiescent state and exhibit episodic X-ray outbursts. The aim of this work is to statistically compare the X-ray luminosity properties of these two classes, focusing on the maximum luminosity and the luminosity variability range . For this purpose, catalog data for Galactic HMXB pulsars were used, including 18 persistent and 64 transient systems. The distributions of and were analyzed using histograms, box plots, cumulative distribution functions (CDFs), and the non-parametric Mann–Whitney test. It is shown that both classes reach similar values of on the order of – erg/s), with no statistically significant difference between their distributions. However, transient systems exhibit a much wider luminosity variability range, reaching increases of 4–5 orders of magnitude (up to ), whereas persistent sources typically show lower variability. This difference is statistically confirmed, with transients demonstrating significantly higher variability p ≈ 0.05). Thus, the main distinction between persistent and transient HMXBs lies not in their peak X-ray luminosity, but in their accretion regime. In persistent systems, the compact object continuously accretes matter from a relatively stable stellar wind of an OB supergiant, resulting in steady X-ray emission. In contrast, transient systems are characterized by intermittent accretion (for example, episodic mass capture from a Be-star circumstellar disc), which leads to their extreme luminosity variability.
Некоторые метрики заблокированы вашими
настройками согласия
ON THE APPROXIMATION OF A BOUNDARY VALUE PROBLEM FOR DELAY INTEGRO-DIFFERENTIAL EQUATIONS
(2025-07-06)
E. А. Bakirova
;
Narkesh B. Iskakova
;
Askarbek E. Imanchiyev
;
Sayakhat G. Karakenova
A linear two-point boundary value problem for a system of integro-differential equations with a constant delay argument is investigated on a finite interval. By dividing the interval by parts, the integral term of the integrodifferential equation with constant delay argument is replaced by the quadrature formula. With this replacement, the linear two-point boundary value problem for a system of integro-differential equations with a constant delay argument is approximated by the linear boundary value problem for a system of loaded differential equations with a constant delay argument. Definitions of correct solvability of boundary value problem for system of integro-differential equations with delay argument and constructed boundary value problem for system of loaded differential equations with constant delay argument are introduced. Conditions of correct solvability of linear boundary value problem for system of integro-differential equations with delay argument and linear boundary value problem for system of loaded differential equations with delay argument are established. Relationship between correct solvabilities of linear two-point boundary value problem for system of integro-differential equations with constant delay argument and approximating linear two-point boundary value problem for system of loaded differential equations with constant delay argument is shown.
Некоторые метрики заблокированы вашими
настройками согласия
CONTROL OF THE SIZES OF LEAD SULFIDE (PBS) NANOPARTICLES BY PLASMA TREATMENT METHOD
(2024-07-02)
G. S. Amirbekova
;
Zhandos Tolepov
;
Nazim R. Guseinov
;
Malika Tulegenova
;
B.G. Orynbai
In this work, the optimal parameters for the production of lead sulfide nanoparticles (PbS) were determined. Lead sulfide nanoparticles were obtained by chemical precipitation in an aqueous solution of lead nitrate (Pb(NO3 )2 ) 25 ml 0.18 M (1.524 g), sodium hydroxide (NaOH) 75 ml 0.38 M (1.172 g), thiourea (CH4 N2 S) 50 ml 0.11 M (0.399 g), at a reaction temperature of 100 °C, the duration of the synthesis reaction was 120 minutes. The particles were deposited on a pre-purified silicon (Si) substrate. After synthesis, the particles were processed in a glow discharge plasma in an argon atmosphere at a pressure of the order of Ð=1 Pa, for t1 =1min and U = 2 min, at a voltage ofU = 2 kV and a current strength of I =1,5 mA. The morphology of the obtained structures was studied using a scanning electron microscope (SEM), the elemental composition of the particles was determined by energy dispersion analysis (EDX). Plasma treatment reduces the average particle size from the submicron to the nanometer range.

Herald of Kazakh-British technical university

Фильтры

Настройки

Сортировать по

результатов на странице

QyzPU CRIS

Университет