494 research outputs found
Experimental study of a transformer with superconducting elements for fault current limitation and energy redistribution
Numerous proposed and developed superconducting fault current limiters and
self-limiting transformers limit successfully fault currents but do not provide
uninterrupted supplying of consumers. A design investigated in the work
combines the functions of a conventional transformer with the functions of fast
energy redistribution and fault protection. The device constitutes a
transformer containing an additional high-temperature superconducting (HTS)
coil short-circuited by a thin film HTS switching element. Fault current
limitation and redistribution of the power flow to a standby line are achieved
as a result of a fast transition of the superconducting switching element from
the superconducting into the normal state. Transient and steady-state
characteristics were experimentally investigated. A mathematical model of the
device operation was proposed, and the calculated results were found to be in
good agreement with the experimental data. The application field and basic
requirements to such devices were discussed and it was shown that the proposed
device meets these requirements.Comment: 15 pages incl. 4 figures. Submitted to "Cryogenics
Generalization of the Grad method in plasma physics
The Grad method is generalized based on the Bogolyubov idea of the functional
hypothesis for states at the end of relaxation processes in a system. The Grad
problem (i.e., description of the Maxwell relaxation) for a completely ionized
spatially uniform two-component electron-ion plasma is investigated using the
Landau kinetic equation. The component distribution functions and time
evolution equations for parameters describing the state of a system are
calculated, and corrections are obtained to the known results in a perturbation
theory in a small electron-to-ion mass ratio.Comment: 10 pages, 2 table
TYC 1031 01262 1: The First Known Galactic Eclipsing Binary with a Type II Cepheid Component
We present the discovery and CCD observations of the first eclipsing binary
with a Type II Cepheid component in our Galaxy. The pulsation and orbital
periods are found to be 4.1523 and 51.38 days, respectively, i.e. this variable
is a system with the shortest orbital period among known Cepheid binaries.
Pulsations dominate the brightness variations. The eclipses are assumed to be
partial. The EB-subtype eclipsing light curve permits to believe that the
binary's components are non-spherical.Comment: 3 pages, 3 figures, accepted to MNRAS Letter
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