2,485,204 research outputs found

    Maximal subgroups of direct products

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    We determine all maximal subgroups of the direct product \sc G^n of \sc n copies of a group~\sc G. If \sc G is finite, we show that the number of maximal subgroups of~\sc G^n is a quadratic function of~\sc n if \sc G is perfect, but grows exponentially otherwise. We~deduce a theorem of Wiegold about the growth behaviour of the number of generators of~\sc G^n.Comment: Plain TeX file, 8 page

    Superdeformed Λ\Lambda hypernuclei with antisymmetrized molecular dynamics

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    The response to the addition of a Λ\Lambda hyperon is investigated for the deformed states such as superdeformation in Λ41^{41}_\LambdaCa, Λ46^{46}_\Lambda Sc and Λ48^{48}_\LambdaSc. In the present study, we use the antisymmetrized molecular dynamics (AMD) model. It is pointed out that many kinds of deformed bands appear in 45^{45}Sc and 47^{47}Sc. Especially, it is found that there exists superdeformed states in 45^{45}Sc. By the addition of a Λ\Lambda particle to 40^{40}Ca, 45^{45}Sc and 47^{47}Sc, it is predicted, for the first time, that the superdeformed states exist in the hypernuclei Λ41^{41}_\LambdaCa and Λ46^{46}_\LambdaSc. The manifestation of the dependence of the Λ\Lambda-separation energy on nuclear deformation such as spherical, normal deformation and superdeformation is shown in the energy spectra of Λ41^{41}_\LambdaCa, Λ46^{46}_\Lambda Sc and Λ48^{48}_\LambdaSc hypernuclei.Comment: 24 pages, 8 figure

    Multi-Dimensional Spatially-Coupled Codes

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    Spatially-coupled (SC) codes are constructed by coupling many regular low-density parity-check codes in a chain. The decoding chain of SC codes stops when facing burst erasures. This problem can not be overcome by increasing coupling number. In this paper, we introduce multi-dimensional (MD) SC codes. Numerical results show that 2D-SC codes are more robust to the burst erasures than 1D-SC codes. Furthermore, we consider designing MD-SC codes with smaller rateloss

    Level Crossing Rate of Macrodiversity System in the Presence of Multipath Fading and Shadowing

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    Macrodiversity system including macrodiversity SC receiver and two microdiversity SC receivers is considered in this paper. Received signal experiences, simultaneously, both, long term fading and short term fading. Microdiversity SC receivers reduces Rayleigh fading effects on system performance and macrodiversity SC receiver mitigate Gamma shadowing effects on system performance. Closed form expressions for level crossing rate of microdiversity SC receivers output signals envelopes are calculated. This expression is used for evaluation of level crossing rate of macrodiversity SC receiver output signal envelope. Numerical expressions are illustrated to show the influence of Gamma shadowing severity on level crossing rate