153 research outputs found

    On the rate of Poisson approximation to partial sum processes

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    We investigate approximation of a Bernoulli partial sum process to the accompanying Poisson process in the non-i.i.d. case. The rate of closeness is studied in terms of the minimal distance in probability

    Killing Spinor Equations from Nonlinear Realisations

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    Starting from a nonlinear realisation of eleven dimensional supergravity based on the group G11, whose generators appear as low level generators of E11, we present a super extended algebra, which leads to a covariant derivative of spinors identical to the Killing spinor equation of this theory. A similar construction leads to the Killing spinor equation of N=1 pure supergravity in ten dimensions.Comment: 16 pages, typos correcte

    Investigation of the microstructure, mechanical properties and thermal stability of nanocomposite coatings based on amorphous carbon

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    The Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings based on amorphous carbon and the nanosized particles were synthesized by magnetron method. The results of the microstructure features and mechanical properties investigations of these coatings are presented. The thermal stability of microstructure and properties of these coatings at tempering up to 900Β°C were investigated. These coatings have a high (11–18 GPa) hardness, low (ΞΌ < 0.2) the coefficient of friction and high thermal stability of the microstructure and properties up to 700Β°C. The features of elastically stressed state of nanosized particles in these coatings were founded. A high local internal stresses in the TiC nanoscale particles do not observed

    Thermal stability of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings

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    The results of the microstructure, mechanical and tribological properties investigations of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings based on amorphous carbon in the initial state and after the annealing to 900 Β°C are presented. The effect of annealing temperature on the microstructure, tribological and mechanical properties of Ti-C- Ni-Cr and Ti-C-Ni-Cr-Al-Si nanostructured coatings is discussed

    Magneto-optic Kerr effect in a spin-polarized zero-moment ferrimagnet

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    The magneto-optical Kerr effect (MOKE) is often assumed to be proportional to the magnetisation of a magnetically ordered metallic sample; in metallic ferrimagnets with chemically distinct sublattices, such as rare-earth transition-metal alloys, it depends on the difference between the sublattice contributions. Here we show that in a highly spin polarized, fully compensated ferrimagnet, where the sublattices are chemically similar, MOKE is observed even when the net moment is strictly zero. We analyse the spectral ellipsometry and MOKE of Mn 2 Ru x Ga, and show that this behaviour is due to a highly spin-polarized conduction band dominated by one of the two manganese sublattices which creates helicity-dependent reflectivity determined by a broad Drude tail. Our findings open new prospects for studying spin dynamics in the infra-red.Comment: 7 pages, 7 figure

    Modeling dynamic distortion of pulse signals arising in dev ice with limited frequency range

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