Solitary state wave-beam in damping systems
Solitary state wave-beam in damping systems
V.K. Grishin, E.N. Shapоshnikоva
In the present article, isolated electromagnetic waves of appreciable amplitude excited by intense electron beams in decelerating systems are investigated. The characteristics of the wave beam are estimated by means of a self-consistent kinetic analysis of the final equilibrium state which appears as a result of nonlinear interaction of the wave beam. It is shown that the particle field is concentrated practically within the cluster. Beam reorganization as a result of the effect of longitudinal autofocusing is considered.
Show AbstractOn the generalization of Nozieres—de Dominicis's theory for X-Ray absorption edges in metals to the case of finite temperature
On the generalization of Nozieres—de Dominicis's theory for X-Ray absorption edges in metals to the case of finite temperature
F.A. Zhivopistsev, F.E. Comas
A generalization of the Nozieres-de Dominicis theory of finite temperature for x-ray spectra at the absorption edge in metals is considered. The formalism of Green's time functions in the case of finite temperatures under the assumption that heat energy is small, is used. It is found that the temperature effect leads to broadening of the spectra lines in the shape of the Gaussian function.
Show AbstractEffect of correlations in ground state and elastic scattering nucleon on nuclei $^{16}$O and $^{40}$Ca
Effect of correlations in ground state and elastic scattering nucleon on nuclei $^{16}$O and $^{40}$Ca
F.A. Zhivopistsev, H. Molina
In the present article, the imaginary part of the optical potential is studied, in light of contributions from an inelastic channel along with excitation of cooperative levels. The computation of Im Vopt is carried out under the assumptions of the Tamm-Dankov and random phase approximations. It is shown that the contribution of the lower cooperative levels (which yield the basic contribution to Im Vopt)is much greater in the random phase approximation than is the Tamm-Dankov approximation. Particular computations are performed for ${16}^$O and ${40}^Ca nuclei.
Show AbstractGamma-quanta angular distributions in the $^{209}$Bi(n,n'Ƴ)reaction
Gamma-quanta angular distributions in the $^{209}$Bi(n,n'Ƴ)reaction
V.D. Avchukhov, K.A. Baskova, А.В. Vovk, L.I. Govor, A.M. Demidоv, M.M. Коmkоv
The angular distribution for the strongest gamma quanta from the reaction ${209}^$Bi (n, n'y) relative to a beam of fast reactor neutrons are measured. The size of mixtures of multiples in the gamma transitions between the ${209}^$Bi levels are determined.
Show AbstractOn the limit resources of the quantum measuring devices
On the limit resources of the quantum measuring devices
F.Ya. Khalili
A convenient method of computing the minimal measurement errors of quantum magnitudes is considered. An example using this, method is presented.
Show AbstractTo the calculation of the three electrods electron gun for the creation of spiral electron beam in MCR with the reforming generation frequency
To the calculation of the three electrods electron gun for the creation of spiral electron beam in MCR with the reforming generation frequency
F.A. Коrоlev, F.M. Abdulkhairоv, A.V. Tulupоv
In the present article a method is proposed for computing the motion of electrons in a three-electrode gun used in a cyclotron-resonance maser. The region of motion is divided into four stages, in each of which the expressions for the strengths of the electrical and magnetic fields are different. Based on a solution of the kinetic equation, the g-factor (ratios of the electron's rotational energy to its translational energy) are computed for different voltages at the electrodes and different strengths of the magnetic field in the interaction region. The results obtained give us a basis for selecting an optimal mode of operation of a particular cyclotron-resonance maser model.
Show AbstractExperimental investigation of nonlinear phenomena in liquid with bubbles
Experimental investigation of nonlinear phenomena in liquid with bubbles
E.P. Lanina
Results are presented from an experimental study of the propagation of acoustic waves in a medium with gas bubbles. It is noted that the dispersive properties of the medium predominate over the nonlinear properties. Autofocussing of an acoustic beam is observed, in which the frequency of the acoustic wave is much greater than the bubble frequency.
Show AbstractThe vertical refraction of normal modes and quasimodes in the underwater acoustic
The vertical refraction of normal modes and quasimodes in the underwater acoustic
V.K. Kuznetsov
Waveguide propagation of underwater sound under the conditions of distance- variable sea depth is accompanied by horizontal refraction of normal waves and quasi modes. Upon their entry into the nonwaveguide zone, vertical refraction leading to emission of sound waves into the subjacent half-space occurs. This phenomenon is studied in the article.
Show AbstractParameters of the indirect exchange in compounds of gadolinium and iron
Parameters of the indirect exchange in compounds of gadolinium and iron
A.K. Kupriyanov, S.A. Nikitin
The sf and sd exchange constants as well as the effective mass of carriers for Gd$_{x}$Y$_{1-x}$Fe$_{3}$ types of compounds are determined on the basis of the theory of indirect exchange and experimental values of hyperfine fields, the Curie temperature, and the resistivity. It is shown that agreement with experiment may be improved if it is supposed that exchange reactions in these complexes are realized not only by means of conductivity electrons, but also by means of d-type collective electrons.
Show AbstractMagnetocaloric effect and magnetic properties of terbium—gadolinium alloys
Magnetocaloric effect and magnetic properties of terbium—gadolinium alloys
S.A.Nikitin, A.S. Andreyenko, G.E. Chuprikov
Measurements of the magnetocaloric effect and degree of magnetization are performed using samples of the system of rare-earth terbium-hadolinium alloys in fields up to 15 kOe in strength in the temperature range 77-350°K. The Curie temperatures of the alloys are determined. In the alloy Tb$_{0,94}$ Gd$_{0,06}$ antiferromagnetic order domains are found. A spin reorientation type of phase transition is observed in a magnetic field applied along the hard magnetization axis in the Curie temperature domain. The experimental results lead us to suppose that the polar diagram of anisotropy energy at low temperatures has additional extrema in alloys containing considerable amounts of gadolinium.
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