Quasiparticle electronic band structure of the alkali metal chalcogenides

The electronic energy band spectra of the alkali metal chalcogenides M$_2$A (M: Li, Na, K, Rb; A: O, S, Se, Te) have been evaluated within the projector augmented waves (PAW) approach by means of the ABINIT code. The Kohn-Sham single-particle states have been found in the GGA (the generalized gradient approximation) framework. Further, on the basis of these results the quasiparticle energies of electrons as well as the dielectric constants were obtained in the GW approximation. The calculations based on the Green's function have been originally done for all the considered M$_2$A crystals, except Li$_2$O.Comment: 8 pages, 8 figure

Excited state properties of polycyclic hydrocarbons based dyes

In this paper we present a comprehensive ab initio study of polycyclic hydrocarbons based dyes. The purpose of the work is to obtain electronic properties of the materials which are supposed to be used in organic electronic devices. The list of materials includes violanthrone (di-benzanthrone) derivatives which are already known as industrial organic dyes. First, we have obtained ground-state properties by performing ab initio eigenvalue calculation within generalized gradient approximation (GGA). Then, Green's function method has been used in order to obtain excited state properties. The exciton eigenvalues, as well as imaginary part of dielectric function (DF) and density of states (DOS), have been evaluated from the Bethe-Salpeter equation (BS). The electronic properties obtained here are in good agreement with available experimental data.Comment: 5 pages, 2 figures, 1 tabl

Electronic properties of AlN crystal doped with Cr, Mn and Fe

The spin-resolved electronic energy band spectra, as well as partial and total density of electronic states of the crystal AlN, doped with Cr, Mn and Fe, have been evaluated within the projector augmented waves (PAW) approach by means of the ABINIT code. The Hartree-Fock exchange for correlated electrons is used to describe the correlated orbitals in the PAW framework. The calculated one-electron energies for electrons of spin up and down are very different. We have found that all the considered crystals are ferromagnetic.Comment: 8 pages, 12 figure

The Role of Strong Electron-Electron Correlations in Forming of the Electron Energy Spectrum and Magnetic Properties of the Mn-Doped ScN Crystal.

Розраховано повні й парціальні щільності електронних станів й електронні енергетичні спектри кристала ScN, легованого Mn, із градієнтними поправками у функціоналі обмінно-кореляційної енергії, без урахування і з урахуванням сильних локальних кореляцій 3d-електронів Sc і Mn. Розрахунки виконані методом проекційних приєднаних хвиль. Отримані результати вказують на важливість врахування локальних кореляцій, без яких кристал є немагнітним металом. Результати, отримані із включенням сильних електронних кореляцій, показують, що кристал є феромагнітним напівметалом. ; Partial density of electronic states and electronic energy spectra of the Mn-doped ScN crystal with gradient corrections in the exchange-correlation energy functional, without and with taking into account the strong local correlations of the 3d-electrons of Sc and Mn, have been evaluated. Calculations are performed by the projector augmented waves method. The results indicate the importance of taking into account local correlations, without which the considered crystal is the nonmagnetic metal. The results obtained with inclusion of strong electronic correlations show that the crystal is ferromagnetic semimetal

Diseño, experiencia en la implementación y perspectivas del programa de maestría "formación profesional en matemáticas"

The author's approach to the design of professional training of future teachers of higher mathematics involves filling the content of training with academic disciplines, research work and industrial practice, which are associated with the formation of competencies from the Federal state educational standard of higher education in the direction of training 44.04.01 Pedagogical education (master's level) and labor actions from the Professional standard "Teacher of vocational training, vocational education and additional professional education". Training is carried out in accordance with the requirements of the principle of professional orientation and the Concept of development of mathematical education in the Russian Federation.El enfoque del autor para el diseño de la formación profesional de futuros profesores de matemáticas superiores implica llenar el contenido de la formación con disciplinas académicas, trabajos de investigación y práctica industrial, que están asociados con la formación de competencias a partir del estándar estatal federal de educación superior en dirección de formación 44.04.01 Educación pedagógica (nivel de maestría) y acciones laborales de la norma profesional "Profesor de formación profesional, educación profesional y educación profesional adicional". La formación se lleva a cabo de conformidad con los requisitos del principio de orientación profesional y el concepto de desarrollo de la educación matemática en la Federación de Rusia

The relationship between the parameters of wind speed

This paper analyzes the methods of mapping the velocity of wind flow, and using them to measure the performance of wind turbines. The dependencies of the two-parameter Weibull distribution function on the scale parameter are analyzed. It should be noted that the parameters of the distribution function, and therefore the repeatability are probabilistic. The characteristics of Rayleigh distribution for different values of the scale are presented. The analytical-expressions and peculiar velocities of the integer and half-integer values for the shape parameters reflect the relationship between the mean, mean square, average-cubic, and estimated wind-speeds. It is shown that the ratio of the square of the average speed to the standard, regardless of the values of the shape-parameters and the scale-ratio can be replaced by the corresponding G-functions.The theoretical-calculation to design the medium-speed and its relation to the current and average speeds for the Weibull distribution with a half-integer values and the shape-parameter is presented. It is proved that the recommendation considers the speed of the medium design to be proportional to the mean, and permissible only if the distribution is close to normal. It has been established that the ratio between average wind velocities (in the case of Weilbull distribution parameter) are determined only by its form and the average velocity through the scale parameter. Weibull distribution allows to facilitate and simplify their calculation methodology so as to assess the energy parameters of wind turbines

Comparative research of efficiency of photovoltaic power systems

The article gives results of the development of the system of monitoring for photovoltaic power installations with different configuration to study the factors, increasing their productivity. Differentiation of impact, made by the components of different structure of photovoltaic power installations is made by application of three independent controlled channels of energy extraction from photovoltaic panels: fixed focused, with application of solar tracker and with application of solar tracker, having flat mirror concentrators. To secure originality of the record of the electric energy, produced by photovoltaic panels, we have developed unit of control for discharging current of battery banks in each channel. It supports equal level of their charge. Amount of the produced electric energy in each channel is estimated by the value of discharge. Control and measuring system is made on the base of virtual devices with hardware unit of input/output of NI USB-6009 type, produced by National Instruments Company, with software LabVIEW. In the research, software code of the system of monitoring and front panel of operator have been developed. The work provides photos of the developed experimental stand

The Quasiparticle Electronic Energy Bands of the Cubic KMgF 3

First-principles calculations have been carried out to study the electronic properties of the KMgF₃ perovskite crystal. On first stage the calculations were performed within the generalized gradient approximation. On the second stage we have evaluated the quasiparticle corrections to the generalized gradient approximation band structure. These significantly improved electronic energies have been found here for the first time on base of the quasiparticle approach as implemented in the ABINIT code. Also, the pressure dependent parameters of electronic energy band spectra were found in the generalized gradient approximation. For the first time the pressure dependent electronic band energies have been evaluated within the quasiparticle approach. The generalized gradient approximation band gap parameters are in good agreement with the literature data, obtained with local density approximation or generalized gradient approximation exchange-correlation functionals and are much underestimated compared with the experiment. The quasiparticle band gap agrees well with the measured value