35,303 research outputs found
Measurements of Pressure Distributions and Force Coefficients in a Squeeze Film Damper. Part 1: Fully Open Ended Configuration
Measurements of pressure distributions and force coefficients were carried out in two types of squeeze film dampers, executing a circular centered orbit, an open-ended configuration, and a partially sealed one, in order to investigate the effect of fluid inertia and cavitation on pressure distributions and force coefficients. Dynamic pressure measurements were carried out for two orbit radii, epsilon 0.5 and 0.8. It was found that the partially sealed configuration was less influenced by fluid inertia than the open ended configuration
Infrared optical absorption spectra of CuO single crystals: Fermion-spinon band and dimensional crossover of the antiferromagnetic order
We have obtained mid-infrared optical absorption spectra of the S=1/2 quasi
one-dimensional CuO using polarized transmission measurement and interpreted
the spectra in terms of phonon assisted magnetic excitations. When the electric
field is parallel to the main antiferromagnetic direction a Delta shaped peak
is observed with the maximum at 0.23eV which is attributed to spinons along
Cu-O chains. At low temperatures in the antiferromagnetic phase another peak
appears at 0.16eV which is attributed to two-magnon absorption but the spinon
peak remains. This behavior is interpreted as due to a dimensional crossover
where the low temperature three-dimensional magnetic phase keeps short range
characteristics of a one-dimensional magnet.Comment: 5 pages, 5 figure
Infrared Hall conductivity of NaCoO
We report infrared Hall conductivity of
NaCoO thin films determined from Faraday rotation angle
measurements. exhibits two types of hole
conduction, Drude and incoherent carriers. The coherent Drude carrier shows a
large renormalized mass and Fermi liquid-like behavior of Hall scattering rate,
. The spectral weight is suppressed and disappears at T
= 120K. The incoherent carrier response is centered at mid-IR frequency and
shifts to lower energy with increasing T. Infrared Hall constant is positive
and almost independent of temperature in sharp contrast with the dc-Hall
constant.Comment: 5 Pages, 5 Figures. Author list corrected in metadata only, paper is
unchange
Spin/Orbital Pattern-Dependent Polaron Absorption in Nd(1-x)Sr(x)MnO3
We investigated optical properties of Nd(1-x)Sr(x)MnO3 (x= 0.40, 0.50, 0.55,
and 0.65) single crystals. In the spin/orbital disordered state, their
conductivity spectra look quite similar, and the strength of the mid-infrared
absorption peak is proportional to x(1-x) consistent with the polaron picture.
As temperature lowers, the Nd(1-x)Sr(x)MnO3 samples enter into various
spin/orbital ordered states, whose optical responses are quite different. These
optical responses can be explained by the spin/orbital ordering
pattern-dependent polaron hopping.Comment: 3 figures (gzipped
Absorption and Emission in the non-Poisson case
This letter adresses the challenging problems posed to the Kubo-Anderson (KA)
theory by the discovery of intermittent resonant fluorescence with a
non-exponential distribution of waiting times. We show how to extend the KA
theory from aged to aging systems, aging for a very extended time period or
even forever, being a crucial consequence of non-Poisson statistics.Comment: 4 pages 3 figures. accepted for publication on Physical Review
Letter
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