419 research outputs found
Laser Doppler instrument measures fluid velocity without reference beam
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
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
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
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
We have measured photoemission spectra of two kinds of TiO-capped VO
thin films, namely, that with rutile-type TiO (r-TiO/VO) and that
with amorphous TiO (a-TiO/VO) capping layers. Below the
Metal-insulator transition temperature of the VO thin films, K,
metallic states were not observed for the interfaces with TiO, in contrast
with the interfaces between the band insulator SrTiO and the Mott insulator
LaTiO in spite of the fact that both TiO and SrTiO are band
insulators with electronic configurations and both VO and LaTiO
are Mott insulators with 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-TiO/VO than in a-TiO/VO, suggesting Ti-V atomic diffusion due
to the higher deposition temperature for r-TiO/VO.Comment: 5 pages, 6 figure
Scalar Field Contribution to Rotating Black Hole Entropy
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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