383 research outputs found

    Spin-orbit-induced correlations of the local density of states in two-dimensional electron gas

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    We study the local density of states (LDOS) of two-dimensional electrons in the presence of spin-orbit (SO) coupling. Although SO coupling has no effect on the average density of states, it manifests itself in the correlations of the LDOS. Namely, the correlation function acquires two satellites centered at energy difference equal to the SO splitting, 2ωSO2\omega_{SO}, of the electron Fermi surface. For a smooth disorder the satellites are well separated from the main peak. Weak Zeeman splitting ωZωSO\omega_{Z} \ll \omega_{SO} in a parallel magnetic field causes an anomaly in the shape of the satellites. We consider the effect of SO-induced satellites in the LDOS correlations on the shape of the correlation function of resonant-tunneling conductances at different source-drain biases, which can be measured experimentally. This shape is strongly sensitive to the relation between ωSO\omega_{SO} and ωZ\omega_{Z}.Comment: 10 pages, 4 figure

    Back gating of a two-dimensional hole gas in a SiGe quantum well

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    A device comprising a low-resistivity, n-type, Si substrate as a back gate to a p-type (boron), remote-doped, SiGe quantum well has been fabricated and characterized. Reverse and forward voltage biasing of the gate with respect to the two-dimensional hole gas in the quantum well allows the density of holes to be varied from 8 × 1011 cm–2 down to a measurement-limited value of 4 × 1011 cm–2. This device is used to demonstrate the evolution with decreasing carrier density of a re-entrant insulator state between the integer quantum Hall effect states with filling factors 1 and 3

    Independent work of students as an essential component of the communicative competence development in the context of the federal state educational standards of higher education

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    The relevance of the researched problem is driven by the need to use the independent work of students at in-class and out-of-class activities at university to develop their communicative competence in the context of implementing the Federal State Educational Standards of Higher Education of the new generation. The purpose of the article is to make a case for the possible and necessary use of the independent work for the development of the students' communicative competence. The leading method of the research is empirical one that allows to monitor the independent work, to measure indicators using specifically designed assignments, tests, etc. and to compare those indicators, as well as methods of mathematical statistics and graphical representation of results. The assignment complex that is necessary and sufficient for the effective development of students' speech competence has been developed and tested: assignments for in-class and out-of-class activities, game situations on professional topics, various events during extracurricular time, etc. The materials of the article can be used in the practical work of teachers of linguistic disciplines not only in universities, but also in colleges, and are also of interest to all those who are involved in professional and pedagogical activity. © Authors

    Tunneling between 2D electron layers with correlated disorder: anomalous sensitivity to spin-orbit coupling

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    Tunneling between two-dimensional electron layers with mutually correlated disorder potentials is studied theoretically. Due to this correlation, the diffusive eigenstates in different layers are almost orthogonal to each other. As a result, a peak in the tunnel I-V characteristics shifts towards small bias, V. This "protects" the peak against the interaction-induced smearing, since the relaxation rate near the Fermi level is low. If the correlation in disorder potentials is complete, the peak position and width are governed by the spin-orbit coupling in the layers; this coupling lifts the orthogonality of the eigenstates. Possibility to use inter-layer tunneling for experimental determination of weak intrinsic spin-orbit splitting of the Fermi surface is discussed.Comment: 5 pages, 5 figures; published version, minor change

    Educational research networks principles of organization

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    Relevance. Modern society has global transformations; as a result, the level characteristics of its system development are changing, new opportunities and new situations to implement a self-organizing system to solve problems of self-government appear. Thus, there is the need to organize the multiplicity of interactions in the new environment, including education. The success of the development mechanisms, organizing innovative activities in the educational systems of different levels is largely determined by the active development of interaction network forms and interaction effective management. The article is devoted to development of theoretical ideas about the processes of network interaction in education to justify and describe the principles of modern scientific-educational network on the basis of system-synergetic approach. A leading approach to study this problem can be considered as system-synergetic which allows studying network interaction within the scientific and educational network as a holistic entity consisting of interrelated elements, structured and complex. The results of the study showed that described principles of effective networking and the conditions of scientific and educational networks development allow you to combine and re-combine the accumulated actors of this knowledge and practical experience interaction, turning them into the means of its innovative activities. The article can be useful to heads of educational institutions of different levels, as well as researchers of innovative processes development problems in education. © 2018 Authors

    Conceptual model of continuing professional education based on social-and-academic approach

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    The importance of the issue in subject derives from the fact that the vocational (professional) education does not really meet the demands of people, society and state that are explained by new qualification requirements to employees in various fields, including forestry, in the modern socio-economic situation. Thus, continuing professional education is particularly important. This article is aimed for development of a conceptual model for continuing professional education based on the potential of this system, that has to be used to its full extent in order to overcome the danger of our country lagging behind the world tendencies in economic and social development and increasing quality of training of forestry workers that possess such qualities as mobility, dynamics, constructiveness, independent thinking and acting. The leading method in research of this issue is modelling that allows us to see the issue as a process of focused and deliberate learning to monitor the quality of education by specialists. The article presents a conceptual model for continuing professional education, reveals its peculiarities, and describes an algorithm for implementation of such model based on socio-academic approach. The model is aimed for successful socialization of students, adaptation to new professional environment and development of scientific and methodological basis for the education quality monitoring. © 2016 Dorozhkin, Saltseva and Steinberg

    The main trends in updating of vocational education in a postindustrial society

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    The article reflects the main trends in the improvement of vocational education in the modern conditions of a postindustrial societyВ статье отражены основные тенденции совершенствования профессионального образования в современных условиях постиндустриального обществ

    Fractional quantum Hall effect without energy gap

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    In the fractional quantum Hall effect regime we measure diagonal (ρxx\rho_{xx}) and Hall (ρxy\rho_{xy}) magnetoresistivity tensor components of two-dimensional electron system (2DES) in gated GaAs/Alx_{x}Ga1x_{1-x}As heterojunctions, together with capacitance between 2DES and the gate. We observe 1/3- and 2/3-fractional quantum Hall effect at rather low magnetic fields where corresponding fractional minima in the thermodynamical density of states have already disappeared manifesting complete suppression of the quasiparticle energy gaps.Comment: 4 pages, 4 figure

    Optimization of the subject matter of profile training disciplines for bachelors' vocational education on the basis of occupational standards

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    Applicability of the issue under study is conditioned by the need in development of principal educational programs by higher education institutions with accounting for requirements of appropriate occupational standards and necessity in reviewing of the requirements of occupational standards and reflecting them within the scope of competences formed. The paper is aimed at substantiation of the subject matter of profile training disciplines for vocational education of bachelors within the context of competence and process approaches and with accounting for occupational standards. The leading method of study of this issue is modeling which allows considering the issue under study as a process of recognized accounting of requirements of appropriate occupational standards wherein employers' opinions are fixed in the regulatory mode. The structural-functional model of selection of the subject matter of profile disciplines for the training program is developed; the following algorithms are developed: 1) of analysis of occupational standards; 2) of comparing of occupational standards with curriculum disciplines; 3) of analysis of the subject matter of labour functions, labour actions, knowledge and skills when developing working programs and assessment resources funds; the model has been successfully tested on the example of profile training of vocational education bachelors. The paper presents the structure-functional model of selection of the subject matter of profile disciplines of the educational program with taking into account of occupational standards requirements which define competences acquired by a graduate, i.e. his/her ability to use knowledge, skills and personal qualities in accordance with the occupational activity; the process approach to implementation of this model is applied. © Authors

    Management of teacher scientific-methodical work in vocational educational institutions on the basis of project-target approach

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    The relevance of the subject under analysis is determined by the lack of theoretical development of the problem of management of teacher scientific-methodical work in vocational educational institutions based upon innovative approaches in the framework of project paradigm. The purpose of the article is to develop and test a science-based structural-functional model of management of teacher scientific-methodical work on the basis of project-target approach. The primary method of study is modeling, which allows to consider the problem as a process of purposeful obtaining skills by teachers of secondary vocational educational institutions to conduct scientific-methodical work on the basis of project-target approach. The article presents a structural-functional model of management of teacher scientific-methodical work. The model comprises a series of components: target, methodological, content, organizational and procedural, evaluation-resultative. The article also suggests a complex of organizational-pedagogical conditions for management of teacher scientific-methodical work on the basis of project-target approach: developing and organizing a management system of teacher scientific-methodical work; building a purposeful teachers’ motivation for scientific-methodical work in the context of changing socio-economic conditions; organizing a system of teachers’ professional development in the field of scientific-methodical work on the basis of project-target approach. The content of the article can be used by Heads of vocational educational organizations, Deputy heads who control methodical work in educational organizations, heads of teacher training programs, as well as college and university teachers in their training students of higher and secondary vocational education. © 2016 Shakuto, Dorozhkin and Kozlova