Vol 2, No 19 (2014)
- Year: 2014
- Published: 30.10.2014
- Articles: 10
- URL: https://ogarev-online.ru/2311-2468/issue/view/19153
Full Issue
The problem of optimality in mathematical model of economic growth long-term forecasting
Abstract
The authors solve the problem of optimum control for mathematical model of economic growth of long-term forecasting. Considering the problem solution, the article presents a system of differential equations describing the trajectories of balanced growth.
Application of newton diagram method for branching equation solution obtained by solving boundary value problem for conservative autonomous duffing equation
Abstract
The authors apply the Newton diagram method to obtain a series expansion of the equation in generalized powers of λ for the solution of the branching. The article includes an example of finding approximate solutions for the branching equation obtained by solving the boundary value problem for the conservative autonomous Duffing equation.
Creating implicit scheme for compressible gas flows simulation
Abstract
The article describes the implicit finite volume upwind scheme in delta-form for calculation of an ideal compressible gas flows. The ability to calculate an implicit finite volume upwind scheme in delta-form for calculation of an ideal compressible gas flows was added to the program for simulation of hydrodynamics cfd-2d, developed by the Chair of Applied Mathematics, Differential Equations and Theoretical Mechanics. The article includes an analysis of typical problems.
Practical realization and solution comparison of some direct numerical methods for optimization dynamic problems: a study of simplified model of mixed population control
Abstract
The article presents a review and a comparative analysis of classical numerical methods for dynamic system optimum control. The study includes an example of the management problem for T. Maltus modified rigid model. The authors present a comparative analysis of the problem analytical solution with its solutions obtained by various numerical methods.
The structure and spectral-luninescent properties of nanosized cryslall powders of YBPO₄:ER
Abstract
The paper presents the results of a study of phase composition, morphology, sizes and spectral-luminescent properties of nanosized crystal powders of YbPO4:Er и YbPO4∙0,8:H2OEr. The luminescence features of these compounds are identified and their possible reasons are suggested.
Parametric amplification of high-frequency radiation in one-dimensional Josephson junction array
Abstract
The article presents a study of parametric generation of the high frequency electromagnetic radiation by Josephson junction arrays. The absorbed power of the external high- frequency radiation in one-dimensional array of identical synchronized series-connected Josephson junctions is calculated, the power of parametric amplification of external radiation is found for the junction array at various load parameters, the effect of load parameters on the gain is studied. The power gain for a thousand-contact array is a few microwatts. That is consistent with the experimental data.
A study of composite materials produced by cold pressing of titanium and aluminum powders
Abstract
The methods of metallography, raster electron microscopy and x-ray diffractometry are applied to investigate the titanium-aluminium composite materials. They were received by uniaxial pressing at room temperature (load 520 MPa) of mixture of titanium and aluminum powders and their subsequent solid-phase sintering in the air at the temperature of 600 oC.
Temperature dependence of the consolidation degree of the spins in bilayer films
Abstract
The authors found a sharp difference in the behavior of the temperature dependence of the spectra of spin wave resonance two-layer films with different layer settings fixing. The calculation confirmed that the effect of the disappearance and the subsequent appearance of spin-wave modes in a certain interval of temperatures is due to the decrease of the degree of consolidation due to the convergence of fields homogeneous resonance in layers of excitation and consolidation of spin fluctuations.
Study of the structure of multilayer metallic coatings on silicon by SEM and AFM
Abstract
The structure and elemental composition of the multilayer metallic coatings used as a transition of the ohmic contact interface system structures of large power semiconductor devices have been identified by chemical etching, etching by focused ion beam, scanning electron microscopy, scanning probe microscopy. The metal coatings were deposited on the surface of the silicon structures by the magnetron sputtering technique. The results demonstrate the efficiency of the combined application of chemical and ion etching, SEM and AFM to study the structure and elemental composition of multilayer metal coatings on silicon.