Mathematical Modeling of Non-Stationary Hydraulic Process Occurring in the Gas Centrifuge Cascade During the Separation of Multicomponent Isotope Mixtures

This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge cascades for separation of multicomponent isotope mixtures

Methods of optimization of hausdorff distance between convex rotating figures

We studied the problem of optimizing the Hausdorff distance between two convex polygons. Its minimization is chosen as the criterion of optimality. It is believed that one of the polygons can make arbitrary movements on the plane, including parallel transfer and rotation with the center at any point. The other polygon is considered to be motionless. Iterative algorithms for the phased shift and rotation of the polygon are developed and implemented programmatically, providing a decrease in the Hausdorff distance between it and the fixed polygon. Theorems on the correctness of algorithms for a wide class of cases are proved. Moreover, the geometric properties of the Chebyshev center of a compact set and the differential properties of the Euclidean function of distance to a convex set are essentially used. When implementing the software package, it is possible to run multiple times in order to identify the best found polygon position. A number of examples are simulated. © 2020 Faculty of Organizational Sciences, Belgrade. All rights reserved

Optimization of the Hausdorff distance between convex polyhedrons in R3

In this article, approximation of sets is under consideration using convex polyhedrons in the three dimensional Euclidean space. In the problem statement, it is necessary to find such disposition of two given polyhedrons A and B that the Hausdorff distance between them obtains the minimal value. Elements of convex analysis, non-smooth analysis, and numerical geometry are used for construction numerical algorithms solving this problem. Numerical algorithms are implemented in the software whose efficiency is demonstrated in applications. © 2015, IFAC Hosting by Elsevier Ltd

Synthesis and photocatalytic properties of materials based on bismuth silicates

The influence of the preparation technique of bismuth silicate-based catalysts on their formation, phase composition, absorption characteristics, and photocatalytic properties is investigated. Samples the with initial ratio of Bi: Si = 2: 1 are prepared via the hydrothermal method with varied temperature conditions in the hydrothermal aging and calcination stages. The synthesized catalysts demonstrate photocatalytic activity in the decomposition of the methanol equilibrium vapor and visible light-induced decolorization of a methylene blue (MB) aqueous solution

Self-consistent calculations of the energy and tunable emission spectra of doping superlattices

Based on the developed method of self-consistent calculations the results of description of tunable optical spectra versus temperature and excitation level for the GaSb doping superlattices of different design are presented. Account of the appearing tails of the density of states allows describing the long-wavelength edges and shape transformation in the spectra of absorption, gain, and luminescence and peculiarities in the optical transitions characteristics. Possible laser diode structures with n-i-p-i crystals in the active region are suggested including ordinary and δ-doped superlattices. Effects of tunable lasing are examined and ways for control of the radiation wavelength are discussed

Molecular packing, piezo- and pyroelectric properties of tert-butyl N-(tert-butoxycarbonyl)-(S)-prolinamide

The work was financially supported by the Russian Foundation for Basic Research (grant no. 16-33-60122). The equipment of the Ural Centre for Shared Use “Modern Nanotechnologies” UrFU and Centre for Joint Use “Spectroscopy and Analysis of Organic Compounds” was used