419 research outputs found

    Laser Doppler instrument measures fluid velocity without reference beam

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    Fluid velocity is measured by focusing laser beam on moving fluid and measuring Doppler shift in frequency which results when radiation is scattered by particles either originally present or deliberately injected into moving fluid

    Investigation of air-flow velocity by laser backscatter

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    Laser light backscatter investigation of air flow velocity in contaminated atmospheres for application to clear air turbulence detector

    Rotation Curves of Spiral Galaxies and Large Scale Structure of Universe under Generalized Einstein Action

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    We consider an addition of the term which is a square of the scalar curvature to the Einstein-Hilbert action. Under this generalized action, we attempt to explain i) the flat rotation curves observed in spiral galaxies, which is usually attributed to the existence of dark matter, and ii) the contradicting observations of uniform cosmic microwave background and non-uniform galaxy distributions against redshift. For the former, we attain the flatness of velocities, although the magnitudes remain about half of the observations. For the latter, we obtain a solution with oscillating Hubble parameter under uniform mass distributions. This solution leads to several peaks of galaxy number counts as a function of redshift with the first peak corresponding to the Great Wall.Comment: 16 page

    Normal Modes and No Zero Mode Theorem of Scalar Fields in BTZ Black Hole Spacetime

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    Eigenfunctions for normal modes of scalar fields in BTZ black hole spacetime are studied. Orthonormal relations among them are derived. Quantization for scalar fields is done and particle number, energy and angular momentum are expressed by the creation and annihilation operators. Allowed physical normal mode region is studied on the basis of the no zero mode theorem. Its implication to the statistical mechanics is also studied.Comment: 11 pages,v2 typos correcte

    Photoemission study of TiO2/VO2 interfaces

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    We have measured photoemission spectra of two kinds of TiO2_2-capped VO2_2 thin films, namely, that with rutile-type TiO2_2 (r-TiO2_2/VO2_2) and that with amorphous TiO2_2 (a-TiO2_2/VO2_2) capping layers. Below the Metal-insulator transition temperature of the VO2_2 thin films, ∼300\sim 300 K, metallic states were not observed for the interfaces with TiO2_2, in contrast with the interfaces between the band insulator SrTiO3_3 and the Mott insulator LaTiO3_3 in spite of the fact that both TiO2_2 and SrTiO3_3 are band insulators with d0d^0 electronic configurations and both VO2_2 and LaTiO3_3 are Mott insulators with d1d^1 electronic configurations. We discuss possible origins of this difference and suggest the importance of the polarity discontinuity of the interfaces. Stronger incoherent part was observed in r-TiO2_2/VO2_2 than in a-TiO2_2/VO2_2, suggesting Ti-V atomic diffusion due to the higher deposition temperature for r-TiO2_2/VO2_2.Comment: 5 pages, 6 figure

    Scalar Field Contribution to Rotating Black Hole Entropy

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    Scalar field contribution to entropy is studied in arbitrary D dimensional one parameter rotating spacetime by semiclassical method. By introducing the zenithal angle dependent cutoff parameter, the generalized area law is derived. The non-rotating limit can be taken smoothly and it yields known results. The derived area law is then applied to the Banados-Teitelboim-Zanelli (BTZ) black hole in (2+1) dimension and the Kerr-Newman black hole in (3+1) dimension. The generalized area law is reconfirmed by the Euclidean path integral method for the quantized scalar field. The scalar field mass contribution is discussed briefly.Comment: 26 page
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