Ab initio study of the phase separation of argon in molten iron at high pressures

Using first-principles molecular dynamics (MD) simulations, we study the solubility of argon in molten iron at high pressures and temperatures. In particular we explore whether the low pressure immiscibility of liquid Fe and Ar persists to high pressure (130 GPa) and temperature (4500K), or whether they mix. Starting from a variety of Fe/Ar mixtures we find that they always separate rapidly into two liquids. We conclude that there is no evidence for a significant increase in the solubility of Ar in Fe at these conditions. We cannot, therefore, attribute the lower melting temperatures of Fe obtained from DAC experiments compared to those obtained from ab initio calculations and shock experiments, to eutectic melting between Fe and the Ar pressure medium

Coherent lidars based on intracavity heterodyning of echo signals

The development and technical realization of the method of laser sounding of the atmosphere based on the effects of mixing of reference and external fields of scattering inside a laser cavity are presented. An approximate theory of the method was developed on the basis of the investigations using the model of a three-mirror laser. The nonlinear effect of a wideband laser on frequency-dependent external influences of the atmosphere was investigated. The field measurements of gaseous composition of the atmosphere were performed on the basis of a given method of coherent reception using a tunable CO2 laser

Exchange interaction and its tuning in magnetic binary chalcogenides

Using a first-principles Green's function approach we study magnetic properties of the magnetic binary chalcogenides Bi2Te3, Bi2Se3, and Sb2Te3. The magnetic coupling between transition-metal impurities is long-range, extends beyond a quintuple layer, and decreases with increasing number of d electrons per 3d atom. We find two main mechanisms for the magnetic interaction in these materials: the indirect exchange interaction mediated by free carriers and the indirect interaction between magnetic moments via chalcogen atoms. The calculated Curie temperatures of these systems are in good agreement with available experimental data. Our results provide deep insight into magnetic interactions in magnetic binary chalcogenides and open a way to design new materials for promising applications

Stabilization of tetragonal/cubic phase in Fe doped Zirconia grown by atomic layer deposition

Achieving high temperature ferromagnetism by doping transition metals thin films is seen as a viable approach to integrate spin-based elements in innovative spintronic devices. In this work we investigated the effect of Fe doping on structural properties of ZrO2 grown by atomic layer deposition (ALD) using Zr(TMHD)4 for Zr and Fe(TMHD)3 for Fe precursors and ozone as oxygen source. The temperature during the growth process was fixed at 350{\deg}C. The ALD process was tuned to obtain Fe doped ZrO2 films with uniform chemical composition, as seen by time of flight secondary ion mass spectrometry. The control of Fe content was effectively reached, by controlling the ALD precursor pulse ratio, as checked by X-ray photoemission spectroscopy (XPS) and spectroscopic ellipsometry. From XPS, Fe was found in Fe3+ chemical state, which maximizes the magnetization per atom. We also found, by grazing incidence X-ray diffraction, that the inclusion of Fe impurities in ZrO2 induces amorphization in thin ZrO2 films, while stabilizes the high temperature crystalline tetragonal/cubic phase after rapid thermal annealing at 600{\deg}C.Comment: 11 pages, 7 figures, 1 Tabl

Альтернативная энергетика Украины: перспективы использования возобновляемых энергоресурсов

Проведено порівняльний аналіз сучасних джерел енергії. Досліджені сучасний стан та перспективи розвитку альтернативних джерел енергії в Україні, зокрема впровадження та використання енергії, виробленї з біомаси. Зроблений аналіз законодавчих актів та державної політики щодо викдористання відновлювальних енергоресурсів. Досліджений вплив використання альтернативних джерел енергії на стан навколишнього середовища. В результаті виконаного аналізу та результатів досліджень запропоновано використання тваринної біомаси в якості альтернативного джерела енергії, показані переваги та недоліки даного ресурсу.A comparative analysis of current energy source was made. The current state and prospects for development of alternative energy sources in Ukraine, including the use of energy produced from biomass, are researched in this article. The analysis of legislation and public policy of using of renewable energy resources was held. The impact of using of alternative energy sources on the environment was researched. As a result of the analysis performed and the results of researches the using of animal biomass as an alternative energy source was proposed and the advantages and disadvantages of this resource was shown.Проведен сравнительный анализ современных источников энергии. Исследованы современное состояние и перспективы развития альтернативных источников энергии в Украине, в частности внедрения и использования энергии, произведенной из биомаси.Сделан анализ законодательных актов и государственной политики относительно использования возобновляемых энергоресурсов. Исследовано влияние использования альтернативных источников энергии на состояние окружающей среды. В результате выполненного анализа и результатов исследований предложено использование животной биомассы в качестве альтернативного источника энергии, показаны преимущества и недостатки данного ресурса

Tight-binding study of high-pressure phase transitions in titanium: alpha to omega and beyond

We use a tight-binding total energy method, with parameters determined from a fit to first-principles calculations, to examine the newly discovered gamma phase of titanium. Our parameters were adjusted to accurately describe the alpha Ti-omega Ti phase transition, which is misplaced by density functional calculations. We find a transition from omega Ti to gamma Ti at 102 GPa, in good agreement with the experimental value of 116 GPa. Our results suggest that current density functional calculations will not reproduce the omega Ti-gamma Ti phase transition, but will instead predict a transition from omega Ti to the bcc beta Ti phase.Comment: 3 encapsulated Postscript figures, submitted to Phyical Review Letter

Theory of the phases and atomistic structure of yttria-doped zirconia

Physical Review

Management of social and psychological risks in the educational environment

Выявляется сущность социального и психологического риска. Анализируются особенности рисков в образовательной среде. Представлены результаты исследования социально-психологических рисков в образовательной среде СПО и предложены основные направления по управлению рисками, которые стали приоритетными в образовательной среде агропромышленного техникумаThe article is devoted to revealing the essence of the concept of social and psychological risk. The features of the risks in the educational environment. The results of the study of social and psychological risks in the educational environment of open source software and the basic directions of risk management, which has become a priority in the educational environment of agro-industrial technical schoo