Global gyrokinetic simulations of intrinsic rotation in ASDEX Upgrade Ohmic L-mode plasmas

Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG) plasmas are performed and the nonlinear generated intrinsic flow shows agreement with the intrinsic flow gradients measured in the core of Ohmic L-mode plasmas at nominal parameters. Simulations utilising the kinetic electron model show hollow intrinsic flow profiles as seen in a predominant number of experiments performed at similar plasma parameters. In addition, significantly larger flow gradients are seen than in a previous flux-tube analysis (Hornsby et al {\it Nucl. Fusion} (2017)). Adiabatic electron model simulations can show a flow profile with opposing sign in the gradient with respect to a kinetic electron simulation, implying a reversal in the sign of the residual stress due to kinetic electrons. The shaping of the intrinsic flow is strongly determined by the density gradient profile. The sensitivity of the residual stress to variations in density profile curvature is calculated and seen to be significantly stronger than to neoclassical flows (Hornsby et al {\it Nucl. Fusion} (2017)). This variation is strong enough on its own to explain the large variations in the intrinsic flow gradients seen in some AUG experiments. Analysis of the symmetry breaking properties of the turbulence shows that profile shearing is the dominant mechanism in producing a finite parallel wave-number, with turbulence gradient effects contributing a smaller portion of the parallel wave-vector

Half-metallicity and efficient spin injection in AlN/GaN:Cr (0001) heterostructure

First-principles investigations of the structural, electronic and magnetic properties of Cr-doped AlN/GaN (0001) heterostructures reveal that Cr segregates into the GaN region, that these interfaces retain their important half-metallic character and thus yield efficient (100 %) spin polarized injection from a ferromagnetic GaN:Cr electrode through an AlN tunnel barrier - whose height and width can be controlled by adjusting the Al concentration in the graded bandgap engineered Al(1-x)Ga(x)N (0001) layers.Comment: submitted for publicatio

Research of sensitivity of some measures of quality assessment of hidden information in the audio content

The paper presents a comparison of some measures of difference between the original signal and the result of the introduction of additional information. The comparison was based on the analysis of the implementation of the results-based steganographic method of spectrum spreading. The paper presents the results of the comparison of some measures of difference based on the analysis of speech signals in their division into segments of equal lengt

Electronic band structure and carrier effective mass in calcium aluminates

First-principles electronic band structure investigations of five compounds of the CaO-Al2O3 family, 3CaO.Al2O3, 12CaO.7Al2O3, CaO.Al2O3, CaO.2Al2O3 and CaO.6Al2O3, as well as CaO and alpha-, theta- and kappa-Al2O3 are performed. We find that the conduction band in the complex oxides is formed from the oxygen antibonding p-states and, although the band gap in Al2O3 is almost twice larger than in CaO, the s-states of both cations. Such a hybrid nature of the conduction band leads to isotropic electron effective masses which are nearly the same for all compounds investigated. This insensitivity of the effective mass to variations in the composition and structure suggests that upon a proper degenerate doping, both amorphous and crystalline phases of the materials will possess mobile extra electrons

Electric field gradients in s-, p- and d-metal diborides and the effect of pressure on the band structure and Tc_c in MgB2_2

Results of FLMTO-GGA (full-potential linear muffin-tin orbital -- generalized gradient approximation) calculations of the band structure and boron electric field gradients (EFG) for the new medium-T$_c$ superconductor (MTSC), MgB$_2$, and related diborides MB$_2$, M=Be, Al, Sc, Ti, V, Cr, Mo and Ta are reported. The boron EFG variations are found to be related to specific features of their band structure and particularly to the M-B hybridization. The strong charge anisotropy at the B site in MgB$_2$ is completely defined by the valence electrons - a property which sets MgB$_2$ apart from other diborides. The boron EFG in MgB$_2$ is weakly dependent of applied pressure: the B p electron anisotropy increases with pressure, but it is partly compensated by the increase of core charge assymetry. The concentration of holes in bonding $\sigma$ bands is found to decrease slightly from 0.067 to 0.062 holes/B under a pressure of 10 GPa. Despite a small decrease of N(E$_F$), the Hopfield parameter increases with pressure and we believe that the main reason for the reduction under pressure of the superconducting transition temperature, T$_c$, is the strong pressure dependence of phonon frequencies, which is sufficient to compensate the electronic effects.Comment: 12 pages, 3 figure

Motivation for higher military education in modern Ukraine

Статья посвящена анализу мотивации получения высшего военного образования в Украине, которую предложено рассматривать на трех этапах ­ выбора профессии, обучения в военном вузе и профессионального становления после получения образования. На основании проведенных авторских исследований качественными и количественными стратегиями выявлено, что на первом этапе основными факторами выбора профессии военнослужащего выступают престиж профессии, гарантия трудоустройства. Определенное влияние оказывают семейные традиции. Показано, что на втором этапе воздействие различных факторов формируют три группы курсантов по силе мотивационных компонентов для получения высшего военного образования: с высокой, средней и низкой силой мотивации. Проведенное исследование показало, что у курсантов доминируют такие ценностные ориентации, как здоровье, счастливая семейная жизнь, наличие хороших и верных друзей и материальная обеспеченность. На основании проведенного компаративного анализа продемонстрировано, что система ценностей курсантов идентична ценностям студентов, наряду с этим, их мотивация на получение профессии более устойчива, чем у последних. Анализ проблем профессионального становления на третьем этапе позволил очертить круг проблем, требующих решения в высших военных учебных заведениях. Среди них: содержание учебных программ, их идентичность практическим аспектам профессиональной деятельности, формирование субъект­субъектных отношений и другие.Статья посвящена анализу мотивации получения высшего военного образования в Украине, которую предложено рассматривать на трех этапах ­ выбора профессии, обучения в военном вузе и профессионального становления после получения образования. На основании проведенных авторских исследований качественными и количественными стратегиями выявлено, что на первом этапе основными факторами выбора профессии военнослужащего выступают престиж профессии, гарантия трудоустройства. Определенное влияние оказывают семейные традиции. Показано, что на втором этапе воздействие различных факторов формируют три группы курсантов по силе мотивационных компонентов для получения высшего военного образования: с высокой, средней и низкой силой мотивации. Проведенное исследование показало, что у курсантов доминируют такие ценностные ориентации, как здоровье, счастливая семейная жизнь, наличие хороших и верных друзей и материальная обеспеченность. На основании проведенного компаративного анализа продемонстрировано, что система ценностей курсантов идентична ценностям студентов, наряду с этим, их мотивация на получение профессии более устойчива, чем у последних. Анализ проблем профессионального становления на третьем этапе позволил очертить круг проблем, требующих решения в высших военных учебных заведениях. Среди них: содержание учебных программ, их идентичность практическим аспектам профессиональной деятельности, формирование субъект­субъектных отношений и другие.This article analyzes the motivation of higher military education in Ukraine, which proposed to consider on three stages – the choice of profession, training in military high school and professional formation after education. Based on the author’s qualitative and quantitative research strategies the authors revealed that on the first stage the main factors of the choice of occupation are soldier prestige of the profession, a guarantee of employment. A certain influence family tradition has. It is shown that on the second stage the impact of various factors forms the three groups of military students on the power of motivational components for higher military education: high, medium and low power motivation. The study showed that the military students choose such values, like health, a happy family life, good and true friends, and financial stability. On the basis of comparative analysis demonstrated that the system of values of military students is identical to the values of students, along with it, their motivation to obtain the profession is more stable than the latter. Analysis of the problems of professional development at the third stage shows the range of problems to be solved in the higher military educational institutions. Among them: the content of the curriculum, their identity to practical aspects of professional activity, the formation of subject­subject relations and others

Electronic structure and light-induced conductivity in a transparent refractory oxide

Combined first-principles and experimental investigations reveal the underlying mechanism responsible for a drastic change of the conductivity (by 10 orders of magnitude) following hydrogen annealing and UV-irradiation in a transparent oxide, 12CaO.7Al2O3, found by Hayashi et al. The charge transport associated with photo-excitation of an electron from H, occurs by electron hopping. We identify the atoms participating in the hops, determine the exact paths for the carrier migration, estimate the temperature behavior of the hopping transport and predict a way to enhance the conductivity by specific doping.Comment: 4 pages including 4 figure

Study of acute and subacute action of iron-molybdenum nanocluster polyoxometalates

There were no significant deviations from the norm in the functional state of the liver, kidneys, and pancreas in the study of the acute toxicity of iron-molybdenum buckyballs intended for targeted drug delivery. No accumulation of nanoparticles or deviation from the norm in any investigated parameter was detected in the study of subacute toxicity. © 2013 Pleiades Publishing, Ltd

Structure peculiarities of cementite and their influence on the magnetic characteristics

The iron carbide $Fe_3C$ is studied by the first-principle density functional theory. It is shown that the crystal structure with the carbon disposition in a prismatic environment has the lowest total energy and the highest energy of magnetic anisotropy as compared to the structure with carbon in an octahedron environment. This fact explains the behavior of the coercive force upon annealing of the plastically deformed samples. The appearance of carbon atoms in the octahedron environment can be revealed by Mossbauer experiment.Comment: 10 pages, 3 figures, 3 tables. submitted to Phys.Rev.