Comparative study of correlation effects in CaVO3 and SrVO3

We present parameter-free LDA+DMFT (local density approximation + dynamical mean field theory) results for the many-body spectra of cubic SrVO3 and orthorhombic CaVO3. Both systems are found to be strongly correlated metals, but not on the verge of a metal-insulator transition. In spite of the considerably smaller V-O-V bond angle in CaVO3 the LDA+DMFT spectra of the two systems for energies E<E_F are very similar, their quasiparticle parts being almost identical. The calculated spectrum for E>E_F shows more pronounced, albeit still small, differences. This is in contrast to earlier theoretical and experimental conclusions, but in good agreement with recent bulk-sensitive photoemission and x-ray absorption experiments.Comment: 15 pages, 6 figure

Development of competence for the discipline «Microprocessor technics» based on FPGA Altera company Cyclone III series

Рассматриваются сравнительные характеристики ПЛИС с другими логическими устройствами и целесообразность развития направления и добавления в курс «Микропроцессорная техника» материала для изучения программируемых логических интегральных схем.Consider the comparative characteristics of the FPGA logic with other devices, and the feasibility of the development direction and adding to course "Microprocessor technics" of the material for the study of FPGA

Synthesis of electric speed controller in the spectral region.

Рассматривается общий порядок и структура алгоритмов решения основной задачи анализа систем управления различных классов при детерминированных воздействиях.We consider the general order and structure of algorithms for solving the basic problems of the analysis of different classes of control systems for deterministic effects

Momentum-resolved spectral functions of SrVO3_3 calculated by LDA+DMFT

LDA+DMFT, the merger of density functional theory in the local density approximation and dynamical mean-field theory, has been mostly employed to calculate k-integrated spectra accessible by photoemission spectroscopy. In this paper, we calculate k-resolved spectral functions by LDA+DMFT. To this end, we employ the Nth order muffin-tin (NMTO) downfolding to set up an effective low-energy Hamiltonian with three t_2g orbitals. This downfolded Hamiltonian is solved by DMFT yielding k-dependent spectra. Our results show renormalized quasiparticle bands over a broad energy range from -0.7 eV to +0.9 eV with small ``kinks'', discernible in the dispersion below the Fermi energy.Comment: 21 pages, 8 figure

Review of integral transformations applied in the tasks of analysis and synthesis of electric drive systems

The paper presents set of integral transformations that can potentially be used to obtain spectral representations of signals of automatic systems. The advantages and disadvantages of the considered transformations for the ACS class, characteristic for the electric drive, are indicated.В данной статье рассмотрен набор интегральных преобразований, которые потенциально могут быть использованы для получения спектральных представлений сигналов автоматических систем Обозначены преимущества и недостатки рассмотренных преобразований для класса САУ, характерных для электропривода

Application of spectral method to synthesis of electric drive control systems

Рассматривается применение спектрального метода к синтезу систем управления электроприводами. Предлагается использовать отличную от традиционной систему базисных функций. Показано, что диадное вейвлет-преобразование сигналов удовлетворяет основным требованиям к системам базисных функций.The purpose of paper is to consider application of spectral approach to the problems of electrical drive control synthesis. The usage of non-conventional basis functions is proposed. It is shown, that dyad wavelet transform satisfies main requirements to such basis functions

Full orbital calculation scheme for materials with strongly correlated electrons

We propose a computational scheme for the ab initio calculation of Wannier functions (WFs) for correlated electronic materials. The full-orbital Hamiltonian H is projected into the WF subspace defined by the physically most relevant partially filled bands. The Hamiltonian H^{WF} obtained in this way, with interaction parameters calculated by constrained LDA for the Wannier orbitals, is used as an ab initio setup of the correlation problem, which can then be solved by many-body techniques, e.g., dynamical mean-field theory (DMFT). In such calculations the self-energy operator \Sigma(e) is defined in WF basis which then can be converted back into the full-orbital Hilbert space to compute the full-orbital interacting Green function G(r,r',e). Using G(r,r',e) one can evaluate the charge density, modified by correlations, together with a new set of WFs, thus defining a fully self-consistent scheme. The Green function can also be used for the calculation of spectral, magnetic and electronic properties of the system. Here we report the results obtained with this method for SrVO3 and V2O3. Comparisons are made with previous results obtained by the LDA+DMFT approach where the LDA DOS was used as input, and with new bulk-sensitive experimental spectra.Comment: 36 pages, 14 figure

Development of setup for predictive testing stator insulation of electrical machines

The article discusses the approach to construction of system of diagnostics of the basic insulation of electrical machines. Discusses the structure of the experimental installation, allowing to organize non-destructive predictive control of insulation of electrical machines. Given the equivalent circuit of the insulation used in foreign sources. The methods of determination of equivalent circuit parameters.В статье рассматривается подход к построению системы диагностики базовой изоляции электрической машины. Обсуждается структура экспериментальной установки, позволяющая организовать неразрушающий прогностический контроль изоляции электрической машины. Приведена схема замещения изоляции, применяемая в зарубежных источниках. Рассмотрены методы определения параметров схемы замещения

Adjustable Electric Drive Based on Radiation-Resistant Induction Motors

The object under consideration is an adjustable electric drive based on radiation-resistant DAR induction motors with a power of 0.75 kW and 2.2 kW, with a nominal stator field rotation speed of 1000 rpm and 1500 rpm and an environmental protection method IP 68, designed to use in the equipment for hydrometallurgical processing of spent nuclear fuel (SNF) of the processing module of the pilot demonstration energy complex (PM PDEC). Bench tests of DAR prototypes confirmed that the developed motors in accordance with electromagnetic parameters, energy and starting characteristics fully comply with serial asynchronous motors of similar power and speed and satisfy the requirements of the technical specifications. The control system with the Altivar ATV212/ATV320 frequency converter ensures stable operation of the DAR in the range of 1:50 speed control in the "sensorless"version, the functions and interface of the control system meet the specified requirements. Recommendations are given on expanding the tasks of automation of the technological process, which can be provided by means of the developed control system based on software implementation. An assessment of the thermal state during liquid cooling of engines during operation from the control system. © Published under licence by IOP Publishing Ltd