An explicit solution to the problem of excitation of oscillations by a current in a waveguide with filling of the type of a locally inhomogeneous insertion is constructed. The resonance characteristics of this problem are considered.
Show AbstractIn the framework of a model of zero-range potential, the problem of electron bound states in the field of two $D^0$-centers (a two-center problem) in a semiconductor quantum wire with a parabolic confinement potential in the presence of a longitudinal magnetic field is considered. Equations describing the $g$- and $u$-terms that correspond to symmetric and antisymmetric states of an electron localized at the $D_2^-$-center are obtained. The terms as functions of the magnetic field strength in the quantum wire with the parabolic confinement potential are studied.
Show AbstractThe start-up of the electron accelerator in the Research Institute of Nuclear Physics, Moscow State University, i. е., a 70-MeV split microtron, opens up new wide possibilities for the generation of secondary beams of photons and neutrons. The ability of this accelerator to generate secondary beams on $^{238}$U targets of various thickness is studied.
Show AbstractThe theoretical prerequisites for, and the experimental indications of the possibility of neutron production in the Earth's atmosphere during thunderstorm activity are discussed. The possibility of observing neutrons produced in lightning discharges in the lower atmosphere and in circumterrestrial space is analyzed. The total number of neutrons produced in a lightning discharge is estimated.
Show AbstractDynamic scattering of light by aqueous micellar polyelectrolyte solutions differing in the degree of polymerization and concentration has been studied. The shape of the polymer-micellar complexes formed is established to be spherical, and their size to depend on the degree of polymerization and concentration of the polyelectrolyte. At high degrees of polymerization of the polyelectrolyte, two types of complexes differing in average size and size distribution variance are observed.
Show AbstractIn a study of the emission properties of films of linear-chain carbon on an insulator layer, the presence of effective emission of electrons into vacuum was revealed. The cathodoluminescence method is used in experiments that corroborate this phenomenon. The current-voltage characteristics are found to be of an exponential nature and, together with the temperature dependence, suggest that there is thermal activation. The absence of a Schottky effect is explained by the geometry of the barrier on which activation takes place; presumably, this is an interchain barrier.
Show AbstractBased on the results of instrumental measurements and theoretical calculations carried out by a team of researchers at the Department of Atmosphere Physics, Physics Faculty, Moscow State University, new data on the heat and mass exchange between the ocean and the atmosphere in the zone of the El Nino phenomenon are obtained. Information obtained by meteorological satellites about tropical cyclones is collected. Analysis performed has shown that the number of tropical cyclones increases substantially in the years of marked El Nino activity.
Show AbstractBased on the theory of vortical turbulence, it is demonstrated that the fine structure of the flow velocity fields in the ocean is due to the presence in the flows of rotating vortices and their interaction with turbulent stresses.
Show AbstractThe altitude dependence of the fine-weather field strength is studied on the basis of a theory explaining the formation of this field as a result of the tidal baroelectric effect—redistribution of charges in an electrically neutral planet exposed to tidal influences.
Show AbstractThe variability of the fourth statistic moment of sea surface slopes is analyzed. The results of measurements taken from an oceanographic platform situated in the Black Sea are used in the analysis. It is demonstrated that the probability of mirror reflection glitters, calculated for actual values of the statistic moments of the sea surface slopes, is higher than that determined for a Gaussian surface.
Show AbstractThe results of the laboratory and mathematical modeling of the nonlinear steady flows developing in an incompressible liquid due to vibrations of a bottom area are presented. The velocity of the flows generated in the ocean by the seismic vibrations of the bottom is estimated.
Show AbstractThe spectra in the IR line He I 10830 Å, the soft X-ray images taken from the Yohkoh satellite, and the magnetic structure in places of bright solar-activity regions, where intense coronal heating in the absence of flares has been recorded, are studied. Several regularities in the interaction between an active region with a strong magnetic shear and a neighboring coronal hole are established. It is assumed that, as a result of magnetic reconnection processes, which constantly take place and involve the open lines of force of the magnetic field of the coronal hole and the (basically) closed lines of force of the active region, bright coronal structures are formed.
Show AbstractIt is shown that nonequilibrium gas-discharge plasma can be used to nonthermally ignite a supersonic jet of a gaseous hydrocarbon propellant. The mathematical modeling of ignition of hydrogen—oxygen, methane—air, and propane—air mixtures has revealed that the effect of nonequilibrium plasma manifests itself most vividly at low temperatures, when the thermal equilibrium ignition time is large.
Show AbstractThe dependence of the maximal gain of a monochromatic signal in one- and two-stage Raman amplifiers for optimal pump spectra is calculated. The peak in the gain for a two-stage Raman amplifier is shown to be shifted to the IR range in relation to the minimum in the absorption of the optical fiber and in relation to the peak in gain in the one-stage Raman amplifier. Finally, a qualitative explanation of the ways of obtaining the spectral dependence of the gain is given.
Show AbstractThe operational principle and the structure of an acoustic spectrograph are discussed. The spectrograph is used to measure the frequency dependence of the propagation velocity and absorption of acoustic waves in viscoelastic media in a frequency range from 20 Hz to 20 MHz.
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