21,014 research outputs found
New energy storage concept uses tapes
Energy storage system uses movable permeable tapes with cathode and electrolyte material that is drawn across an anode to produce electric power. The system features long shelf life, high efficiency, and flexible operation
SU(m|n) supersymmetric Calogero-Sutherland model confined in harmonic potential
In this work, we study a continuous quantum system of a mixture of bosons and
fermions with the supersymmetry SU(m|n). The particles are confined in a
harmonic well and interact with each other through the 1/r2 interaction. The
ground state wavefunction is constructed explicitly for the most general
SU(m|n) case, with the ground state energy given explicitly. The full energy
spectrum of excitations in the SU(m|n) model is also equal spaced. In the
limiting case where there are no bosons in the system, our results reduce to
those obtained previously.Comment: 9 pages, preprint of ETH-Lausanne (August 1996
Ground States and Flux Configurations of the Two-dimensional Falicov-Kimball Model
The Falicov-Kimball model is a lattice model of itinerant spinless fermions
("electrons") interacting by an on-site potential with classical particles
("ions"). We continue the investigations of the crystalline ground states that
appear for various filling of electrons and ions, for large coupling. We
investigate the model for square as well as triangular lattices. New ground
states are found and the effects of a magnetic flux on the structure of the
phase diagram is studied. The flux phase problem where one has to find the
optimal flux configurations and the nuclei configurations is also solved in
some cases. Finaly we consider a model where the fermions are replaced by
hard-core bosons. This model also has crystalline ground states. Therefore
their existence does not require the Pauli principle, but only the on-site
hard-core constraint for the itinerant particles.Comment: 42 pages, uuencoded postscript file. Missing pages adde
Results from a Second RXTE Observation of the Coma Cluster
The RXTE satellite observed the Coma cluster for 177 ksec during November and
December 2000, a second observation motivated by the intriguing results from
the first 87 ksec observation in 1996. Analysis of the new dataset confirms
that thermal emission from isothermal gas does not provide a good fit to the
spectral distribution of the emission from the inner 1 degree radial region.
While the observed spectrum may be fit by emission from gas with a substantial
temperature gradient, it is more likely that the emission includes also a
secondary non-thermal component. If so, non-thermal emission comprises ~8% of
the total 4--20 keV flux. Interpreting this emission as due to Compton
scattering of relativistic electrons (which produce the known extended radio
emission) by the cosmic microwave background radiation, we determine that the
mean, volume-averaged magnetic field in the central region of Coma is B =
0.1-0.3 microgauss.Comment: 10 pages, 1 figure; APJ, in pres
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