44,496 research outputs found

    Stability and asymptotic behavior of periodic traveling wave solutions of viscous conservation laws in several dimensions

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    Under natural spectral stability assumptions motivated by previous investigations of the associated spectral stability problem, we determine sharp LpL^p estimates on the linearized solution operator about a multidimensional planar periodic wave of a system of conservation laws with viscosity, yielding linearized L1LpLpL^1\cap L^p\to L^p stability for all p2p \ge 2 and dimensions d1d \ge 1 and nonlinear L1HsLpHsL^1\cap H^s\to L^p\cap H^s stability and L2L^2-asymptotic behavior for p2p\ge 2 and d3d\ge 3. The behavior can in general be rather complicated, involving both convective (i.e., wave-like) and diffusive effects

    Beach face dynamics as affected by ground water table elevations

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    This report presents the results of laboratory studies which were carried out in the Coastal and Oceanographical Engineering Laboratory to investigate the effects of ground water table elevations on the beach profile changes over the swash zone. The experiment was conducted at three different water table levels while the other experimental conditions were fixed to constant values with regular waves. The water table levels included (1) normal water table level which is the same as mean sea level, (2) a higher level and (3) a lower level than the mean sea level. Special attention was given to the higher water level to investigate whether this level enhances erosion of the beach face and also to methods of interpreting the experimental data. The experiment described herein was carried out with a fairly fine sand and has demonstrated the significance of beach water table on profile dynamics. The increased water table level caused distinct effects in three definite zones. First, erosion occurred at the base of the beach face and the sand eroded was carried up and deposited on the upper portion of the beach face. Secondly, the bar trough deepened considerably and rapidly and the eroded sand was deposited immediately landward. This depositional area changed from mildly erosional to strongly depositional. Third, the area seaward of the bar eroded with a substantial deepening. The lowered water table appeared to result in a much more stable beach and the resulting effects were much less. The only noticeable trend was a limited deposition in the scour area at the base of the beach face. (Document has 37 pages.

    Polarization enhancement in d(p\vec{d}(\vec{p},2^2He)n reaction: Nuclear teleportation

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    I show that an experimental technique used in nuclear physics may be successfully applied to quantum teleportation (QT) of spin states of massive matter. A new non-local physical effect the `quantum-teleportation-effect' is discovered for the nuclear polarization measurement. Enhancement of the neutron polarization is expected in the proposed experiment for QT that discriminates {\it only} one of the Bell states.Comment: 3 pages, accepted for publication in J. Phys.

    Peierls substitution in the energy dispersion of a hexagonal lattice

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    The method of the Peierls substitution in studying the magnetic subband structure of a hexagonal lattice is re-examined. Several errors in the formalism of a couple of recent papers are pointed out and rectified so as to describe the effect of the magnetic field pertinently.Comment: 3 pages (two-columns), 2 EPS figures, submitted to J. Phys.: Condens. Matte

    A Study of Some Methods for Measuring CKM CP Violating Phases

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    We study the influence of penguin (especially, electroweak penguin) effects on some methods of measuring the angles α\alpha, β\beta, and γ\gamma in the CKM unitarity triangle. We use next-to-leading order effective Hamiltonian, and present numerical estimates based on the factorization approximation. We find that some techniques suggested in the literature, especially for α\alpha determination, are not workable in light of the electroweak penguin effects. Nevertheless, there are methods that would work for each angle determination. For angle β\beta we consider BD+DB \rightarrow D^{+} D^{-} mode and estimate the penguin contamination. For angle γ\gamma we consider a method based on SU(3) symmetry and carefully consider SU(3) breaking effects. We point out regions in the parameter space where this method could be used reliably.Comment: 25 pages (Latex), 5 PS figs (uuencoded, epsf.tex