The equation of motion for the center of mass of a Brownian- "smeared" charged nonquantum particle is obtained. It is shown that the solutions to this equation physically correctly describe the effects of radiation reaction for a nonrelativistic moving body of finite size.
Show AbstractFor $(3+1)$-dimensional systems invariant under transformations that form a Poincare group, the Bogolyubov group variables are defined. This makes it possible to carry out quantization near a time-dependent classical scalar field. The constants of motion and the field operators are found to within the zeroth order in reciprocal powers of the coupling constant.
Show AbstractUsing a standard procedure, conserved currents are constructed in curved backgrounds in $D$-dimensional gravity in the form of divergences of antisymmetric tensor densities (superpotentials). The latter feature two properties: they substantially depend on second derivatives in the Lagrangian of the theory and they do not depend on divergences added*. In particular, these conserved currents and superpotentials are constructed for perturbations in the cosmological models with branes for the Gauss-Bonnet Lagrangian.
Show AbstractThe spectral problem for the system of Maxwell equations in an infinite hollow cylindrical waveguide with a local obstacle is considered. In the case where the medium's parameters in the obstacle depend only on the longitudinal coordinate, the existence of an infinite sequence of trapped modes is shown.
Show AbstractA mathematical description of the change in the number of erythrocytes caused by various factors such as an electron beam, a pulsed electric field, and also their combination is presented. The model allows for the specific feature of the kinetic curves typical of the combined action of dissimilar factors. The theoretical relationships obtained agree well with the available experimental data.
Show AbstractIn the framework of a (3+l)-dimensional extended model of QED at finite temperature and in the presence of a weak (as compared to the fermion mass) constant homogeneous chromomagnetic field, the one-loop radiative corrections to the Chern—Simons topological term are studied.
Show AbstractTransmutation of atomic nuclei under the influence of high-intensity $\gamma$-quanta beams leads to formation of chemical elements with the charge $Z$ and mass number A differing from those of the initial irradiated isotope. A new concept of a transmutation track is introduced, which is the time evolution of the distribution density in $A$ and $Z$ of the number of nuclei produced during transmutation. The transmutation track makes it possible to clearly demonstrate the transmutation process in its dynamics and to reveal general trends and global behavior of a transmutation chain.
Show AbstractReflection of polarized neutrons from a multilayer film, including layers of soft and hard magnetics and characterized by spiral variation of the magnetization vector in the soft-magnetic layer is studied. It is demonstrated that information on the depth variation of the magnetization vector direction in the soft-magnetic layer can be obtained using waveguide enhancement of the neutron flux in the layer.
Show AbstractCalculations for an inversion-recovery pulse sequence intended for simultaneous suppression of water and fat signals in experiments of magnetic resonance tomography are presented. The effectiveness of the technique is illustrated by three-dimensional visualization of pathological intracranial growths.
Show AbstractConsidering the thermoelectret effect, the process of depolarization of a thin dielectric film exposed to electron beam has been studied. It is established that this effect increases the rate of decay of the potential on the target surface and the time of charge relaxation in the sample's bulk. It is shown that the thermoelectret effect can be used in indirect measurements of the electron-beam resist temperature in electron-beam lithography.
Show AbstractThe phenomenon of domain magnetic screening of specimens in the external and internal magnetostatic fields has been detected. The effectiveness of domain screening by a strip domain structure in a film of the magnetostatic field of a cylindrically shaped nonuniformity is studied.
Show AbstractAs a result of studies of the magnetic properties of alloys belonging to the Yb(Fe$_{1-x}$Mn$_x$)$_2$ pseudobinary system it is found that for compositions with $0\le x\le0.4$, the magnetization temperature dependences have compensation points whose position on the temperature scale is a nonmonotonic function of the alloy composition. It is also shown that the simple two-sublattice model can be used in interpreting the magnetic properties of only the intermetallic compound YbFe$_2$ and the pseudobinary alloys Yb(Fe$_{1-x}$Mn$_x$)$_2$ with low Mn concentration ($x\sim0.1$). At higher Mn concentrations, the simple ferrimagnetic model proves to be unsuitable for interpreting the experimental data.
Show AbstractData have been obtained on the effect the addition of complex inorganic molecules K$_4$[Ru$_2$Cl$_{10}$O] produces on the dielectric properties and phase transition in KH$_2$PO$_4$ crystals (KDP). It is shown that selective penetration of the impurity in the prismatic growth sector {010} of the crystal causes a significant suppression of the domain contribution to the permittivity of this sector. The dielectric properties of the pyramidal sector {101} are virtually identical to the properties of a pure crystal. Measurements in the vicinity of the phase transition temperature have shown that the peak of $\varepsilon_c$ in an impurity-containing sector is shifted for 0.35 К to lower temperatures compared to a pure crystal.
Show AbstractThe possibility to reconstruct the structure of the ionosphere $E$ and $D$ regions by the ray radio tomography method is analyzed. Relative contributions of the $E$ and $D$ regions to the experimental data are estimated. They show that it is virtually impossible to reconstruct the $D$ region. By numerical modeling examples and the data of the radio tomography experiment conducted in South East Asia, the possibility to reconstruct the $E$ region of the ionosphere is demonstrated.
Show AbstractThe properties of polarization bremsstrahlung (PB) generated by the interaction of high-energy charges and atomic electrons are studied using fullerenes. It is found that in this case PB exhibits some characteristic features (intensity oscillations at high-frequencies and a sharp increase in intensity at low frequencies) that make it possible to identify fullerenes.
Show AbstractProvided that the decomposition process follows the continuous path, quantitative phase analysis of Ti- and Zr-based alloys, that decompose according to the scheme $\beta_{\bf met}\to\beta+\alpha$, is shown to be possible. The accuracy of determining the concentration of the $\beta$-solid solution and the amount of the equilibrium $\alpha$-phase produced in the decomposition process are estimated.
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