3,788 research outputs found

    New Results on the π+π\pi^{+}\pi^{-} Electroproduction Cross Sections off Protons

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    In these proceedings we present preliminary π+π\pi^{+}\pi^{-} electroproduction cross sections off protons in the kinematical area of 1.4 GeV <W<< W < 1.8 GeV and 0.4 GeV2^{2} <Q2<1.1< Q^{2} < 1.1 GeV2^{2}. Our results extend the kinematical coverage for this exclusive channel with respect to previous measurements. Furthermore, the π+π\pi^{+}\pi^{-} electroproduction cross sections were obtained for Q2Q^2-bins of much smaller size. The future analysis of this data within the framework of the JLAB-MSU reaction model (JM) will considerably improve our knowledge on the Q2Q^2 evolution of the transition γvNN\gamma_{v}NN^* electrocouplings, in particular for the resonances with masses above 1.6 GeV.Comment: Will be published in proceedings of NSTAR 2011 conference. 4 pages, 4 figure

    Non-homogeneous random walks, subdiffusive migration of cells and anomalous chemotaxis

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    This paper is concerned with a non-homogeneous in space and non-local in time random walk model for anomalous subdiffusive transport of cells. Starting with a Markov model involving a structured probability density function, we derive the non-local in time master equation and fractional equation for the probability of cell position. We show the structural instability of fractional subdiffusive equation with respect to the partial variations of anomalous exponent. We find the criteria under which the anomalous aggregation of cells takes place in the semi-infinite domain.Comment: 18 pages, accepted for publicatio

    Trapped mode resonances in metalo-dielectric structures with electric asymmetry materials

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    This paper investigates the possibility of exciting high quality trapped resonant modes on frequency selective surfaces consisting of identical sub-wavelength metallic inclusions (symmetrically split rings) with no structural asymmetry but exhibitting electrical asymmetry. The electrical symmetry is broken by using different dielectric substrates. The existence of such anti-symmetric trapped mode on geometrical symmetric structure is demonstrated through numerical simulation. Numerical results suggest that the high quality factor observed for these resonant modes is achieved via weak coupling between the "trapped modes" and free space which enables the excitation of these modes

    Elliptical dichroism: operating principle of planar chiral metamaterials

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    We employ a homogenization technique based on the Lorentz electronic theory to show that planar chiral structures (PCSs) can be described by an effective dielectric tensor similar to that of biaxial elliptically dichroic crystals. Such a crystal is shown to behave like a PCS insofar as it exhibits its characteristic optical properties, namely, co-rotating elliptical polarization eigenstates and asymmetric, direction-dependent transmission for left/right-handed incident wave polarization.Comment: 3 pages, version as accepted in Optics Letters but before final shortening

    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
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