1,551 research outputs found

    Least-squares deconvolution based analysis of stellar spectra

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    In recent years, astronomical photometry has been revolutionised by space missions such as MOST, CoRoT and Kepler. However, despite this progress, high-quality spectroscopy is still required as well. Unfortunately, high-resolution spectra can only be obtained using ground-based telescopes, and since many interesting targets are rather faint, the spectra often have a relatively low S/N. Consequently, we have developed an algorithm based on the least-squares deconvolution profile, which allows to reconstruct an observed spectrum, but with a higher S/N. We have successfully tested the method using both synthetic and observed data, and in combination with several common spectroscopic applications, such as e.g. the determination of atmospheric parameter values, and frequency analysis and mode identification of stellar pulsations.Comment: Proceedingspaper, 8 pages, 4 figures, appears in "Setting a New Standard in the Analysis of Binary Stars", Eds K. Pavlovski, A. Tkachenko, and G. Torres, EAS Publications Serie

    Application of projects for formation of primary students informative activity

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    In the article on the basis of modern scientific and methodical literature analysis educational projects’ place in modern school education has been studied. The role of project-based learning in the formation and development of younger students’ research curiosity has been revealed. Methodological expediency of the method in elementary school with the aim of students’ familiarity with scientific activities has been proved. Based on practical experience the most possible and favorable options for project activities have been revealed. The basic measures to avoid the most common mistakes when using project methods in elementary school have been grounded. The necessity of expanding the project beyond classes and individual discipline has been proved.Keywords: learning project, identity, collaboration, activity, consciousness, development, scienc

    Effects of Ferromagnetic Magnetic Ordering and Phase Transition on the Resistivity of Spin Current

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    It has been shown experimentally a long time ago that the magnetic ordering causes an anomalous behavior of the electron resistivity in ferromagnetic crystals. Phenomenological explanations based on the interaction between itinerant electron spins and lattice spins have been suggested to explain these observations. We show by extensive Monte Carlo simulation that this behavior is also observed for the resistivity of the spin current calculated as a function of temperature (TT) from low-TT ordered phase to high-TT paramagnetic phase in a ferromagnet. We show in particular that across the critical region, the spin resistivity undergoes a huge peak. The origin of this peak is shown to stem from the formation of magnetic domains near the phase transition. The behavior of the resistivity obtained here is compared to experiments and theories. A good agreement is observed.Comment: 7 pages, 3 figures, accepted, to appear in J. Appl. Phy

    Magnetoelectric control of topological phases in graphene

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    Topological antiferromagnetic (AFM) spintronics is an emerging field of research, which involves the topological electronic states coupled to the AFM order parameter known as the Néel vector. The control of these states is envisioned through manipulation of the Néel vector by spin-orbit torques driven by electric currents. Here we propose a different approach favorable for low-power AFM spintronics, where the control of the topological states in a two-dimensional material, such as graphene, is performed via the proximity effect by the voltage induced switching of the Néel vector in an adjacent magnetoelectric AFM insulator, such as chromia. Mediated by the symmetry protected boundary magnetization and the induced Rashba-type spin-orbit coupling at the interface between graphene and chromia, the emergent topological phases in graphene can be controlled by the Néel vector. Using density functional theory and tight-binding Hamiltonian approaches, we model a graphene/Cr2O3 (0001) interface and demonstrate nontrivial band gap openings in the graphene Dirac bands asymmetric between the K and K′ valleys. This gives rise to an unconventional quantum anomalous Hall effect (QAHE) with a quantized value of 2e^2/h and an additional steplike feature at a value close to e^2/2h, and the emergence of the spin-polarized valley Hall effect (VHE). Furthermore, depending on the Néel vector orientation, we predict the appearance and transformation of different topological phases in graphene across the 180° AFM domain wall, involving the QAHE, the valley-polarized QAHE, and the quantum VHE, and the emergence of the chiral edge states along the domain wall. These topological properties are controlled by voltage through magnetoelectric switching of the AFM insulator with no need for spin-orbit torques

    Polarization-controlled modulation doping of a ferroelectric from first principles

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    In a ferroelectric field effect transistor (FeFET), it is generally assumed that the ferroelectric gate plays a purely electrostatic role. Recently it has been shown that in some cases, which could be called 'active FeFETs', electronic states in the ferroelectric contribute to the device conductance as the result of a modulation doping effect in which carriers are transferred from the channel into the ferroelectric layers near the interface. Here we report first-principles calculations and model analysis to elucidate the various aspects of this mechanism and to provide guidance in materials choices and interface termination for optimizing the on-off ratio, using BaTiO3/n-SrTiO3 and PbTiO3/n-SrTiO3 as prototypical systems. It is shown that the modulation doping is substantial in both cases, and that extension of an electrostatic model developed in previous work provides a good description of the transferred charge distribution. This model can be used to suggest additional materials heterostructures for the design of active FeFETs.Comment: 9 pages, 8 figure

    Formation of psychological readiness for reading of foreign science texts

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    L'article est consacré au problème de l'apprentissage des compétences à acquerir, par les etudiants des departements techniques, pour la lecture des textes scientifiques dans une langue étrangère. Les principaux domaines de recherche des problèmes posés par la psychologie de la lecture et la préparation psychologique sont étudiés. L’auteur décrit les composantes de la préparation psychologique des étudiants qui vont travailler avec des textes scientifiques dont la spécificité peut affecter leur compréhension. Le rôle de l’enseignant de langue étrangère dans la motivation des étudiants à travailler avec des textes scientifiques est mis en évidence. Le but des exercices pratiques est la formation et la préparation psychologique des étudiants à travailler avec des textes scientifiques dans une langue étrangère; on présente les connaissances, les compétences et les expériences sur lesquelles sont formés les étudiants et qu’ils devront exposer et maîtriser à l’issue de leur formation. On prévoit les résultats de l'approbation de la série des exercices portant sur les futures leçons.Стаття присвячена актуальній проблемі навчання студентів технічних спеціальностей роботі з іншомовними науковими текстами. Розглянуто основні напрямки дослідження проблем психології читання та психологічної готовності до діяльності. Описано компоненти психологічної готовності студентів до роботи з іншомовними науковими текстами, які впливають на розуміння тексту. Підкреслена важливість роль викладача іноземної мови професійного спрямування у мотивуванні студентів до роботи з іншомовною науковою літературою у допомозі долати когнітивні утруднення протягом читання. Представлені мета комплексу практичних занять, спрямованих на формування психологічної готовності студентів до роботи з іншомовними науковими текстами; знання, уміння та досвід, які повинні сформуватися і продемонструвати студенти після закінчення занять. Спрогнозовані результати апробації майбутнього комплексу практичних занять.The article deals with an extremely important problem of teaching technical department students to work with science texts in foreign language. The main areas of researches devoted to reading psychology problems and psychological readiness are examined. In the introduction the author justifies the importance of foreign languages learning in formation of technical department students and the role of the teacher in their motivation to read science texts and to overcome cognitive difficulties during reading. As scientists frequently use a specific, mathematical language, with symbols and formulas that are difficult to ground in everyday experience and that often require extreme precision a teacher must learn students to be ready for these difficulties and to overcome them. The author gives proof of creating of practical course that would improve reading and comprehension skills. It is also very important to take into account such individual psychological features as multiple intelligence, learning style of each student and so on. The components of psychological readiness of students to work with foreign science texts that influence their comprehension are described. The author presents the objective of the Foreign Language for Specific Purposes lessons, aimed at creating a psychological readiness of students to the work with foreign science literature; knowledge, skills and experience that should be formed and developped on these lessons. They predicted the results of testing these FLSP lessons

    DEAF SPACE AND THE VISUAL WORLD - BUILDINGS THAT SPEAK: AN ELEMENTARY SCHOOL FOR THE DEAF

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    Deaf Space and the Visual World is a set of principles providing understanding of the perceptions and special needs of the deaf. More frequently deaf and hard of hearing school children are attending mainstream public schools, in which deaf-friendly design is not well-understood or implemented. This work analyzes these principles and applies them to the design of a mainstream elementary school at a site within the King Farm community of Rockville, Maryland. Primarily, the ideas of establishing visual connectivity, circulation, collective being, and sense of home guided the school design. These are reflected in numerous design features of the school that will benefit not only the deaf students, but hearing and other special needs children as well. The ultimate objective of this work is to promote understanding of the needs of the deaf in educational settings, as well as to establish a useful set of architectural guidelines
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