5,996 research outputs found

    TECHNOLOGIZATION OF TEACHING AS THE DIRECTION OF INNOVATION TRANSFORMATION OF THE PEDAGOGICAL REALITY

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    В статье рассматриваются возможности использования технологического подхода к обучению, встраивания современного образования в технологический режим (применение информационно-компьютерных технологий, компетентностного подхода к технологиям обучения, проектирование средств и процедур оценивания учебной деятельности и результатов обучения)The article discusses the possibility of using a technological approach to learning, embedding modern education in the technological mode (the use of information and computer technologies, competence approach to learning technologies, design tools and procedures for assessing learning activities and learning outcomes

    Optimization of a charge-state analyzer for ECRIS beams

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    A detailed experimental and simulation study of the extraction of a 24 keV He-ion beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 pi mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16 to 45%

    Anisotropy and effective dimensionality crossover of the fluctuation conductivity of hybrid superconductor/ferromagnet structures

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    We study the fluctuation conductivity of a superconducting film, which is placed to perpendicular non-uniform magnetic field with the amplitude H0H_0 induced by the ferromagnet with domain structure. The conductivity tensor is shown to be essentially anisotropic. The magnitude of this anisotropy is governed by the temperature and the typical width of magnetic domains dd. For dLH0=Φ0/H0d\ll L_{H_0}=\sqrt{\Phi_0/H_0} the difference between diagonal fluctuation conductivity components Δσ\Delta\sigma_\parallel along the domain walls and Δσ\Delta\sigma_\perp across them has the order of (d/LH0)4(d/L_{H_0})^4. In the opposite case for dLH0d\gg L_{H_0} the fluctuation conductivity tensor reveals effective dimensionality crossover from standard two-dimensional (TTc)1(T-T_c)^{-1} behavior well above the critical temperature TcT_c to the one-dimensional (TTc)3/2(T-T_c)^{-3/2} one close to TcT_c for Δσ\Delta\sigma_\parallel or to the (TTc)1/2(T-T_c)^{-1/2} dependence for Δσ\Delta\sigma_\perp. In the intermediate case dLH0d\approx L_{H_0} for a fixed temperature shift from TcT_c the dependence Δσ(H0)\Delta\sigma_\parallel(H_0) is shown to have a minimum at H0Φ0/d2H_0\sim\Phi_0/d^2 while Δσ(H0)\Delta\sigma_\perp(H_0) is a monotonically increasing function.Comment: 11 pages, 8 figure

    Superpolynomials for toric knots from evolution induced by cut-and-join operators

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    The colored HOMFLY polynomials, which describe Wilson loop averages in Chern-Simons theory, possess an especially simple representation for torus knots, which begins from quantum R-matrix and ends up with a trivially-looking split W representation familiar from character calculus applications to matrix models and Hurwitz theory. Substitution of MacDonald polynomials for characters in these formulas provides a very simple description of "superpolynomials", much simpler than the recently studied alternative which deforms relation to the WZNW theory and explicitly involves the Littlewood-Richardson coefficients. A lot of explicit expressions are presented for different representations (Young diagrams), many of them new. In particular, we provide the superpolynomial P_[1]^[m,km\pm 1] for arbitrary m and k. The procedure is not restricted to the fundamental (all antisymmetric) representations and the torus knots, still in these cases some subtleties persist.Comment: 23 pages + Tables (51 pages

    HOMFLY and superpolynomials for figure eight knot in all symmetric and antisymmetric representations

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    Explicit answer is given for the HOMFLY polynomial of the figure eight knot 414_1 in arbitrary symmetric representation R=[p]. It generalizes the old answers for p=1 and 2 and the recently derived results for p=3,4, which are fully consistent with the Ooguri-Vafa conjecture. The answer can be considered as a quantization of the \sigma_R = \sigma_{[1]}^{|R|} identity for the "special" polynomials (they define the leading asymptotics of HOMFLY at q=1), and arises in a form, convenient for comparison with the representation of the Jones polynomials as sums of dilogarithm ratios. In particular, we construct a difference equation ("non-commutative A-polynomial") in the representation variable p. Simple symmetry transformation provides also a formula for arbitrary antisymmetric (fundamental) representation R=[1^p], which also passes some obvious checks. Also straightforward is a deformation from HOMFLY to superpolynomials. Further generalizations seem possible to arbitrary Young diagrams R, but these expressions are harder to test because of the lack of alternative results, even partial.Comment: 14 page

    Intersections of quadrics, moment-angle manifolds, and Hamiltonian-minimal Lagrangian embeddings

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    We study the topology of Hamiltonian-minimal Lagrangian submanifolds N in C^m constructed from intersections of real quadrics in a work of the first author. This construction is linked via an embedding criterion to the well-known Delzant construction of Hamiltonian toric manifolds. We establish the following topological properties of N: every N embeds as a submanifold in the corresponding moment-angle manifold Z, and every N is the total space of two different fibrations, one over the torus T^{m-n} with fibre a real moment-angle manifold R, and another over a quotient of R by a finite group with fibre a torus. These properties are used to produce new examples of Hamiltonian-minimal Lagrangian submanifolds with quite complicated topology.Comment: 14 pages, published version (minor changes
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