Within the framework of scalar electrodynamics, the construction of an interaction operator of two scalar particles is considered for the local quasi-potential equation obtained by the "rationalization" method from the Logunov-Tavkhelidze equation. The relativistic spectrum of a two-meson bound state is calculated with an accuracy of $\alpha^{4}$.
Show AbstractAn asymptotic solution of the Kazantsev equation is constructed in the limit of high magnetic Reynolds numbers; the rate of growth in the energy, the excitation threshold, and the structure of the magnetic-field correlation function are calculated, and compared with the results of numerical integration of the Kazantsev equation.
Show AbstractThe accuracy of experimental interpretation is determined by the model of the measurement scheme adopted and so does not allow the experimental results to be fully characterized if the reliability of the model is unknown. The concept of the reliability of the model is defined and analyzed in the present work as the minimum probability of erroneous rejection of the model on the basis of measurement results in some set of alternatives.
Show AbstractA scheme for the orthogonal Galerkin method is constructed on the basis of generalization of the partial-region method to a complex space with a pseudoscalar product. This scheme is applicable to the solution of the boundary problem for the Helmholtz equation in a strip with piecewise-constant non-self-conjugate boundary conditions of impedance type.
Show AbstractThe Raman scattering spectra in crystals of the ammonium-sulfate family are investigated. In the external-vibration spectra of the [(NH$_{4}$)$_{1-x}$Rb$_x$]$_{2}$SO$_{4}$ and (NH$_4$)$_2$SO$_4$ at room temperature, two vibrations of symmetry A are seen; their frequency depends linearly on the ionic radius of the cation and monotonically on its mass ($\approx$1/$\sqrt{M}$). A dependence of the internal vibration frequency $\nu _{1}$ of the SO$_{4}^{-2}$ group on the type of cation is observed.
Show AbstractAn instrument with semiconductor telescopes is described; the basic factors determining its resolving power are considered; experimental data characterizing the operation of the instrument on a spacecraft are given.
Show AbstractFor the example of angular moments, the sensitivity of the angular characteristics of electron-photon cascades to details of the description of elementary interactions is investigated. The physical accuracy of models widely used to describe Rutherford scattering is studied: the Landau and small-angle approximations, and the case when screening and the finite nuclear dimensions are taken approximately into account. Specific calculations are made for the mean cosine and the mean-square angle for electrons and photons in air and lead.
Show AbstractEffects associated with the time of flight of charge carriers through the crystal volume in rutile-based materials in the presence of carrier injection from the contacts and of space-charge-limited currents are observed. Measuring the time of flight of injected charge carriers allows the microscopic mobility of the charge carriers in single crystals of reduced rutile to be determined.
Show AbstractThe self-consistent problem of incoherent photoexcitation of a straight-band nondegenerate intrinsic self-conductor is considered in the limiting cases of slow and fast electron-electron relaxation. A dependence of the concentration of free charge carriers on the pumping energy is obtained. The absorption of the pulse propagating in the semiconductor is studied.
Show AbstractThe deactivation of triplet states of the dyes eosin and erythrosine in the presence of external heavy atoms (EHA) of iodine (the salt KI) is studied by the method of pulsed lamp excitation of the luminescence and triplet-triplet absorption of aqueous solutions of these dyes. It is found that, in conditions of constant concentration of the triplet dye molecules, the influence of EHA results in ignition of slow fluorescence of type E due to intensification of the rate of intercombinational transition of the molecules to the singlet excited state.
Show AbstractThe nuclear-magnetic-resonance (NMR) spectra of $^{89}$Y and $^{57}$Fе in the compunds YFe$_{2}$ and Gd$_{0,2}$Y$_{0,8}$Fe$_{2}$ under omnidirectional compression are obtained. Analysis of the experimental results allows the dependence of the parameters of indirect exchange interaction on the volume to be estimated.
Show AbstractThe magnetocaloric effect, magnetostriction, and thermal expansion of terbium-dysprosium alloys in the region of magnetic phase transitions is experimentally investigated. On the basis of the results obtained, a magnetic phase diagram of Tb-Dy alloys is plotted, the change in magnetoelastic energy in the phase transition from helicoidal antiferromagnetism to ferromagnetism is calculated, and it is shown that this change is responsible for the large heat of transition and the magnetocaloric effect.
Show AbstractA matrix theory of the specular reflection of resonant radiation from the smooth surface of a medium containing M$\stackrel{..}{o}$ssbauer nuclei is developed, taking account of possible changes in the parameters of the hyperfine interactions close to the surface. The basic optical characteristics of the medium required to solve the reflection problem - the propagation matrix, the normal-refraction and surface-impedance tensors - are expressed in the first approximation in terms of the amplitudes of coherent nuclear resonant scattering.
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