1,984 research outputs found
Universal mathematical model of power three-phase transformers and autotransformers
The substantiation of necessity in essential increase of completeness and reliability of modeling processes in energy systems has been shown. The results of synthesis of universal mathematical model of one of the main elements of energy systems - power transformers and autotransformers are given. The demanded quality of reproduction of processes is confirmed by experience of using the developed model in structure of all-mode multiprocessing modeling complexes of real time of the hybrid type. The examples illustrating quality of process modeling are shown
On the spectrum of facet crystallization waves at the smooth 4He crystal surface
The wavelike processes of crystallization and melting or crystallization
waves are well known to exist at the 4He crystal surface in the rough state.
Much less is known about crystallization waves for the 4He crystal surface in
the smooth well-faceted state below the roughening transition temperature. To
meet the lack, we analyze here the spectrum of facet crystallization waves and
its dependence upon the wavelength, perturbation amplitude, and the number of
possible facet steps distributed somehow over the wavelength. All the
distinctive features of facet crystallization waves from conventional waves at
the rough surface result from a nonanalytic cusplike behavior in the angle
dependence for the surface tension of smooth crystal facets.Comment: 7 pages, 3 figures, 1 tabl
Oxygen and nitrogen abundances of HII regions in six spiral galaxies
Spectroscopic observations of 63 HII regions in six spiral galaxies (NGC 628,
NGC 783, NGC 2336, NGC 6217, NGC 7331, and NGC 7678) were carried out with the
6-meter telescope (BTA) of Russian Special Astrophysical Observatory with the
Spectral Camera attached to the focal reducer SCORPIO in the multislit mode
with a dispersion of 2.1A/pixel and a spectral resolution of 10A. These
observations were used to estimate the oxygen and nitrogen abundances and the
electron temperatures in HII regions through the recent variant of the strong
line method (NS calibration). The parameters of the radial distribution (the
extrapolated central intercept value and the gradient) of the oxygen and
nitrogen abundances in the disks of spiral galaxies NGC 628, NGC 783, NGC 2336,
NGC 7331, and NGC 7678 have been determined. The abundances in the NGC 783, NGC
2336, NGC 6217, and NGC 7678 are measured for the first time. Galaxies from our
sample follow well the general trend in the luminosity - central metallicity
diagram for spiral and irregular galaxies.Comment: 11 pages, 7 figures, 6 tables. Accepted for publication in MNRA
Transfer ionization and its sensitivity to the ground-state wave function
We present kinematically complete theoretical calculations and experiments
for transfer ionization in HHe collisions at 630 keV/u. Experiment and
theory are compared on the most detailed level of fully differential cross
sections in the momentum space. This allows us to unambiguously identify
contributions from the shake-off and two-step-2 mechanisms of the reaction. It
is shown that the simultaneous electron transfer and ionization is highly
sensitive to the quality of a trial initial-state wave function
Photocurrent in nanostructures with asymmetric antidots
The steady current induced by electromagnetic field in a 2D system with
asymmetric scatterers is studied. The scatterers are assumed to be oriented
cuts with one diffusive and another specular sides. Besides, the existence of
isotropic impurity scatterers is assumed. This simple model simulates the
lattice of half-disk which have been studied numerically recently. The model
allows the exact solution in the framework of the kinetic equation. The static
current response in the second order of electric field is obtained. The
photogalvanic tensor contains both responses to linear and circular
polarization of electromagnetic field. The model possesses non-analyticity with
regards to the rate of impurity scattering.Comment: 9 pages, 6 figure
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