3,293 research outputs found

    Modeling of wave distribution in layered inhomogeneous environment containing a flux of discrete inhomogeneities

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    The algorithm of modeling wave distribution in layered random environment containing a stream of discrete inhomogeneities has been developed and realized. Dependences of dispersed and absorbed signal energies on the parameters describing inhomogeneous structure of random layered environment and inhomogeneity flux were investigated. Numerical calculations of angular spectrum of dispersed signal were carried out. Frequency spectrum of a signal passed through the flux of discrete inhomogeneities was analyze

    On the asymptotic convergence of the polynomial collocation method for singular integral equations and periodic pseudodifferential equations

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    summary:We prove the convergence of polynomial collocation method for periodic singular integral, pseudodifferential and the systems of pseudodifferential equations in Sobolev spaces HsH^{s} via the equivalence between the collocation and modified Galerkin methods. The boundness of the Lagrange interpolation operator in this spaces when s>1/2s>1/2 allows to obtain the optimal error estimate for the approximate solution i.e. it has the same rate as the best approximation of the exact solution by the polynomials

    Evolutionary trade-offs between reproduction and dispersal in populations at expanding range boundaries

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    During recent climate warming, some species have expanded their ranges northwards to keep track of climate changes. Evolutionary changes in dispersal have been demonstrated in these expanding populations and here we show that increased dispersal is associated with reduced investment in reproduction in populations of the speckled wood butterfly, Pararge aegeria. Evolutionary changes in flight versus reproduction will affect the pattern and rate of expansion at range boundaries in the future, and understanding these responses will be crucial for predicting the distribution of species in the future as climates continue to warm

    Magneto-optical response in bimetallic metamaterials

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    We demonstrate resonant Faraday polarization rotation in plasmonic arrays of bimetallic nano-ring resonators consisting of Au and Ni sections. This metamaterial design allows to optimize the trade-off between the enhancement of magneto-optical effects and plasmonic dissipation. Although Ni sections correspond to as little as ~6% of the total surface of the metamaterial, the resulting magneto-optically induced polarization rotation is equal to that of a continuous film. Such bimetallic metamaterials can be used in compact magnetic sensors, active plasmonic components and integrated photonic circuits

    Interaction of flying electromagnetic doughnut with nanostructures

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    We report on the electromagnetic properties of the single-cycle "flying doughnut" electromagnetic permutations in the context of their interactions with nanoscale objects, such as dielectric and plasmonic nanoparticles
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