20,777 research outputs found

    Transport properties of continuous-time quantum walks on Sierpinski fractals

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    We model quantum transport, described by continuous-time quantum walks (CTQW), on deterministic Sierpinski fractals, differentiating between Sierpinski gaskets and Sierpinski carpets, along with their dual structures. The transport efficiencies are defined in terms of the exact and the average return probabilities, as well as by the mean survival probability when absorbing traps are present. In the case of gaskets, localization can be identified already for small networks (generations). For carpets, our numerical results indicate a trend towards localization, but only for relatively large structures. The comparison of gaskets and carpets further implies that, distinct from the corresponding classical continuous-time random walk, the spectral dimension does not fully determine the evolution of the CTQW.Comment: 10 pages, 6 figure

    Self-forming shim or gasket for mounting heavy equipment

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    Soft, cross-serrated aluminum shims are used as mating gaskets between uneven surfaces. Under pressure, the aluminum flows to conform with surface irregularities, forming a plane of uniform bearing

    Radiation data definitions and compilation for equipment qualification data bank

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    Dose definitions, physical properties, mechanical properties, electrical properties, and particle definitions are listed for insulators and dielectrics, elastomeric seals and gaskets, lubricants, adhesives, and coatings

    Composite gaskets are compatible with liquid oxygen, resist compression set

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    Gaskets fabricated by laminating fluorocarbon polymers with fiber glass cloth have a low compression set. Their flexibility is not subject to drastic changes at the temperature of liquid oxygen with which they are used. The fabrication process is controlled so that the fibers are not impregnated with the polymer

    Singular integrals on Sierpinski gaskets

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    We construct a class of singular integral operators associated with homogeneous Calder\'{o}n-Zygmund standard kernels on dd-dimensional, d<1d <1, Sierpinski gaskets EdE_d. These operators are bounded in L2(μd)L^2(\mu_d) and their principal values diverge μd\mu_d almost everywhere, where μd\mu_d is the natural (d-dimensional) measure on EdE_d

    On the Local-Global Conjecture for integral Apollonian gaskets

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    We prove that a set of density one satisfies the local-global conjecture for integral Apollonian gaskets. That is, for a fixed integral, primitive Apollonian gasket, almost every (in the sense of density) admissible (passing local obstructions) integer is the curvature of some circle in the gasket.Comment: 64 pages, 3 figures; Appendix by Peter Varj

    O-ring gasket test fixture

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    An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring
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