591 research outputs found

    Profile measurements of plasma columns using microwave resonant cavities

    Get PDF
    Microwave resonant cavity measurements of radial electron density profile of positive column of gas discharg

    Lorentz transformation and vector field flows

    Full text link
    The parameter changes resulting from a combination of Lorentz transformation are shown to form vector field flows. The exact, finite Thomas rotation angle is determined and interpreted intuitively. Using phase portraits, the parameters evolution can be clearly visualized. In addition to identifying the fixed points, we obtain an analytic invariant, which correlates the evolution of parameters.Comment: 11 pages, 3 figures. Section IV revised and title change

    Shear instabilities of freely standing thermotropic smectic-A films

    Full text link
    In this Letter we discuss theoretically the instabilities of thermotropic freely standing smectic-A films under shear flow\cite{re:wu}. We show that, in Couette geometry, the centrifugal force pushes the liquid crystal toward the outer boundary and induces smectic layer dilation close to the outer boundary. Under strong shear, this effect induces a layer buckling instability. The critical shear rate is proportional to 1/d1/\sqrt{d}, where dd is the thickness of the film.Comment: 12 pages, 2 figure

    Texture Specific Mass Matrices and CP violating asymmetry in B^o_d({\bar B}^o_d) -> \psi K_S

    Full text link
    In the context of texture 4 - zero and texture 5 - zero hierarchical quark mass matrices, CP violating asymmetry in Bdo(Bˉdo)ψKSB^o_d({\bar B}^o_d) \to \psi K_S (sin2β\beta) has been evaluated by considering quark masses at mZm_Z scale. For a particular viable texture 4 - zero mass matrix the range of sin2\beta is: 0.27 - 0.60 and for the corresponding texture 5 - zero case it is 0.31 - 0.59. Further our calculations reveal a crucial dependence of sin2β\beta on light quark masses as well as the phase in this sector.Comment: 10 latex pages, 4 EPS figure

    Testing the predictive ability of technical analysis using a new stepwise test without data snooping bias

    Get PDF
    In the finance literature, statistical inferences for large-scale testing problems usually suffer from data snooping bias. In this paper we extend the "superior predictive ability" (SPA) test of Hansen (2005, JBES) to a stepwise SPA test that can identify predictive models without potential data snooping bias. It is shown analytically and by simulations that the stepwise SPA test is more powerful than the stepwise Reality Check test of Romano and Wolf (2005, Econometrica). We then apply the proposed test to examine the predictive ability of technical trading rules based on the data of growth and emerging market indices and their exchange traded funds (ETFs). It is found that technical trading rules have significant predictive power for these markets, yet such evidence weakens after the ETFs are introduced. © 2009.preprin