6,984 research outputs found
Effective charging energy for a regular granular metal array
We study the Ambegaokar-Eckern-Sch\"{o}n (AES) model for a regular array of
metallic grains coupled by tunnel junctions of conductance and calculate
both paramagnetic and diamagnetic terms in the Kubo formula for the
conductivity. We find analytically, and confirm by numerical path integral
Monte Carlo methods, that for the conductivity obeys an Arrhenius law
with an effective charging energy
when the temperature is sufficiently low, due to a subtle cancellation between
inelastic-cotunneling contributions in the paramagnetic and diamagnetic
terms. We present numerical results for the effective charging energy and
compare the results with recent theoretical analyses. We discuss the different
ways in which the experimentally observed
law could be attributed to disorder.Comment: 5 pages, 3 figures, ReVTeX; added estimates of effective charging
energies and discussion of effects of disorde
A study of longitudinal oscillations of propellant tanks and wave propagations in feed lines. Part II - Wave propagation in elastic pipe filled with incompressible viscous fluid
Fluid wave propagation in liquid propellant feed syste
Estimating Third-Order Moments for an Absorber Catalog
Thanks to the recent availability of large surveys, there has been renewed
interest in third-order correlation statistics. Measures of third-order
clustering are sensitive to the structure of filaments and voids in the
universe and are useful for studying large-scale structure. Thus, statistics of
these third-order measures can be used to test and constrain parameters in
cosmological models. Third-order measures such as the three-point correlation
function are now commonly estimated for galaxy surveys. Studies of third-order
clustering of absorption systems will complement these analyses. We define a
statistic, which we denote K, that measures third-order clustering of a data
set of point observations and focus on estimating this statistic for an
absorber catalog. The statistic K can be considered a third-order version of
the second-order Ripley K-function and allows one to study the abundance of
various configurations of point triplets. In particular, configurations
consisting of point triplets that lie close to a straight line can be examined.
Studying third-order clustering of absorbers requires consideration of the
absorbers as a three-dimensional process, observed on QSO lines of sight that
extend radially in three-dimensional space from Earth. Since most of this
three-dimensional space is not probed by the lines of sight, edge corrections
become important. We use an analytical form of edge correction weights and
construct an estimator of the statistic K for use with an absorber catalog. We
show that with these weights, ratio-unbiased estimates of K can be obtained.
Results from a simulation study also verify unbiasedness and provide
information on the decrease of standard errors with increasing number of lines
of sight.Comment: 19 pages, 4 figure
Vlasov Description Of Dense Quark Matter
We discuss properties of quark matter at finite baryon densities and zero
temperature in a Vlasov approach. We use a screened interquark Richardson's
potential consistent with the indications of Lattice QCD calculations.
We analyze the choices of the quark masses and the parameters entering the
potential which reproduce the binding energy (B.E.) of infinite nuclear matter.
There is a transition from nuclear to quark matter at densities 5 times above
normal nuclear matter density. The transition could be revealed from the
determination of the position of the shifted meson masses in dense baryonic
matter. A scaling form of the meson masses in dense matter is given.Comment: 15 pages 4 figure
Microminiaturized, biopotential conditioning system (MBCS)
Multichannel, medical monitoring system allows almost complete freedom of movement for subject during monitoring periods. System comprises monitoring unit (biobelt), transmission line, and data acquisition unit. Belt, made of polybenzimidizole fabric, is wrapped around individual's waist and held in place by overlapping sections of Velcro closure material
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