Discretization of radio signals in a parametric circuit with video pulse pumping
Discretization of radio signals in a parametric circuit with video pulse pumping
V.P. Komolov and V.A. Roznyatovskii
The results of an experimental investigation of the conversion of modulated radio signals in a parametric circuit with video-pulse pumping are presented. The possibility of using such a circuit as an effective high-speed device for gating modulated radio signals which enables the signal/noise ratio in synchronous reception to be improved is demonstrated.
Show AbstractNonlinear amplification of sound in piezoelectrical semiconductors and self-synchronization of modes in acoustoelectric generators
Nonlinear amplification of sound in piezoelectrical semiconductors and self-synchronization of modes in acoustoelectric generators
P.S. Landa
The shape and amplitude of the oscillations of carrier density, of the electric field, and of elastic displacement in the saturation mode is calculated for nonlinear amplification of sound by crystals of piezoelectric semiconductor. The results obtained provide a qualitative picture of the self-synchronization mode of operation in acoustoelectric generators.
Show AbstractThe theory of reflection from a mossbauer mirror. the anisotropic case
The theory of reflection from a mossbauer mirror. the anisotropic case
M.A. Andreeva, S.F. Borisova and R.N. Kuz'min
The theory of the mirror reflection of Mossbauer radiation for specimens containing Mossbauer nuclei when there is hyperfirie interaction, investigated in 1963 by Bernstein et al is investigated. On the basis of an invariant approach to the optics of anisotropic and gyrotropic media, developed by Fedorov, a general solution is obtained of the boundary value problem in the most general case when the reflecting medium is represented by permittivity and permeability tensors of arbitrary form. The reflection coefficient Is expressed in terms of the natural polarizations of the refracted wave. Detailed calculations of the natural polarizations and the reflection coefficient are made for the case when μ=1 and ε=1+ас с*, and also for ε=1, and μ= 1+ас с*. The need to separate the contributions of the electric and magnetic currents to the generalized permittivity function e when solving the boundary value problems is pointed out. Estimates are given for the difference in the correct expressions for the reflection coefficient from Fresnel's relations in the general case for weakly anisotropic media ($α~10^{4}$)and glancing angles of incidence ($θ~10^{-3}$), and it is found that these differences may reach 10%.
Show AbstractSuperradiation under bragg diffraction conditions
Superradiation under bragg diffraction conditions
A.V. Andreev, R.V. Arutyunyan, and Yu.A. Il'inskii
The kinetics of superfluorescence under anomalous gamma-quanta penetration conditions are considered. It is shown that when the Bragg condition is satisfied the superfluorescence mode is similar to the singlemode condition with certain characteristic values of the parameters. The direction of propagation of the Borrmann mode is a distinct direction in the crystal. The radiation pattern of the radiation will be determined by the intersection of the diffraction pattern of the working material and the Bragg diffraction cone. The use of high-multipole working transitions may reduce the generation threshold by an order of magnitude.
Show AbstractEffect of electron irradiation on the growth of films of certain metals (Al, Сu, Sb) on dielectric substrates
Effect of electron irradiation on the growth of films of certain metals (Al, Сu, Sb) on dielectric substrates
E.M. Dubinina, S.S. Elovikov, A.S. Ovsyanitskii, G.P. Netishenskayas and E.P. Kirilenko
The effect of electron irradiation on the growth of films of Al, Cu, and Sb on single-crystal specimens (NaCl) and on unoriented substrates of glassceramic and silicon monoxide (SiO) is investigated. It is shown that when layers of these metals are grown on crystals of NaCl electron bombardment usually leads to a reduction in the epitaxy temperature. Films deposited on amorphous specimens have greater degree of ordering when bombarded with electrons.
Show AbstractA form of the equations of the many-body problem
A form of the equations of the many-body problem
L.G. Luk'yanov
A transformation, which is a generalization of the Nekhyil transformation for the limited three-body problem is considered for the equations of the many-body problem in a moveable system of coordinates. The angle of natural rotation of the movable system of coordinates is taken as the independent variable, while the coordinates are subjected to a compression transformation. It is shown that the equations of motion after this transformation preserve the symmetry properties of the solutions, known for the initial equations.
Show AbstractThe variational principle in the general theory of relativity
The variational principle in the general theory of relativity
V.N. Ponomarev and A.A. Tseitlin
It is pointed out that the Hilbert Lagrangian in the general theory of relativity (the scalar of the curvature) is not characteristic for the boundary value problem for Einstein's equations in view of its linearity with respect to the leading derivative of the metric. This is due to the fact that for the boundary term in the variation of the action to vanish it is necessary to specify additional boundary conditions which contradict the order of Einstein's equations. This is illustrated with an example from mechanics. The characteristic Lagrangian for Einstein's equations is the "truncated" Dirac Lagrangian (following from the guage approach to the general theory of relativity), operation with which is similar to the addition to the Hilbert Lagrangian of a "boundary term" (as was assumed by Gibbons and Hawking). The need for this addition is pointed out.
Show AbstractCherenkov radiation of monochromatic beams of particles taking their interaction into account
Cherenkov radiation of monochromatic beams of particles taking their interaction into account
I. V. Lupandin
A formula Is derived for the intensity of the Cherenkov radiation of a beam of particles taking the dispersion of the velocities and of the initial coordinates and interference effects into account. The intensity of the radiation turns out to be dependent on the parameters characterizing the coordinate and velocity distribution of the particles of the beam, and also on the duration of the radiation. Models of the experiments to study the energy and spatial parameters of beams of particles are discussed.
Show AbstractNonlinear high-frequency properties of disordered semiconductors
Nonlinear high-frequency properties of disordered semiconductors
I.P. Zvyagin
A kinetic equation is obtained for the high-frequency components of the filling function of local states in disordered semiconductors. The equation obtained is used to estimate the nonlinear susceptibility due to migrations between localization centers randomly situated in space.
Show AbstractThe hierarchical model of the universe and particles
The hierarchical model of the universe and particles
D.D. Ivanenko and V.G. Krechet
A new static spherically symmetrical solution of the combined Einstein system of equations and the massive vector field is given taking the cosmological term into account. The solution can be regarded as an analog of the well-known Schwartzchild and Reissner-Nordstrom solutions for the case of a self- gravitating massive vector field. It is shown that the configuration considered forms a closed nonuniform cosmological model, whose mass and radius correspond in order of magnitude to the same parameters of the observed Universe. It turns out that when the length scale is changed, the cosmological model obtained has the parameters of an elementary particle.
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