Taking into account the invariance of measuring systems under a certain group of transformations has made it possible to materially simplify the solution of the problem of construction of an optimal measuring computer system. The problem is to obtain an optimal reduction transform (defining the processing algorithm) for an ill-defined measuring system. The case of parametric information on the measuring scheme is considered.
Show AbstractThe Weyl quantization rules that allow one to obtain quantum analogs of equations of motion for a wide class of dynamical systems with flat phase space are considered.
Show AbstractThe correctness theorem for the boundary-value problem of scattering on an inhomogeneity in a layered medium has been proved. It has been demonstrated that in order to construct an approximate solution of the boundary-value scattering problem within the framework of the discrete sources method, it suffices to approximate the conjugacy conditions on the scatterer surface in the norm $L_2$.
Show AbstractSpin dynamics of a charged particle with an anomalous magnetic moment in an arbitrary constant magnetic field is studied. A class of fields for which the solution of the Bargmann-Michel-Telegdi equation can be represented in an analytical form is found.
Show AbstractEarlier results are extended to sets of bounded monotone functions with countably many points of discontinuity of the first kind on an interval. The uniform convergence of approximate solutions to the exact solution on a certain subset of this interval is proved.
Show AbstractTo construct higher-order corrections to the Kramers-Henneberger approximation, a formal analogy between the classical averaging method and the Kramers-Henneberger method of approximate description of atomic system dynamics in a strong monochromatic field is applied.
Show AbstractThe dominant role of the selection rules imposed on excitation and decay of the $S_{11}(1535)$- and $D_{13}(1520)$-resonance subnucleonic degrees of freedom of the nucleus by the spin structure of the vertex functions is considered in regard to coherent $\eta$-meson photoproduction from nuclei with $J=T=0$.
Show AbstractCherenkov radiation generated by cosmic-ray particles in the upper atmosphere is theoretically investigated. The possibility of using this radiation to determine the chemical composition of the L-group cosmic rays with elemental resolution and to measure the flux of antiprotons, and also to search for antinuclei with energies of 0.4--4 TeV/nucleon is demonstrated. The applicability of the investigation method suggested to the individual measurements of the electron and positron energy spectra in the range from $\sim$40 GeV to $\sim$ TeV is analyzed. The starry-sky background is evaluated, and the requirements for the angular aperture of the experimental setup are determined.
Show AbstractAn approach to describing wide-frequency-spectrum waves propagating in a randomly inhomogeneous medium is developed. A model inhomogeneous layer in the form of an infinitely thin phase-changing screen is considered. As an extension to a finite-thickness layer, a Burgers-type equation for the average field, which allows one to simultaneously take account of nonlinear effects is obtained. In the phase-changing screen approximation, the averaged profiles and statistical characteristics of the peak pressure of an $N\!$-shaped shock pulse at the shock wave front are determined.
Show AbstractAn amplitude-frequency algorithm for detecting weak gravitational pulses against the non-Gaussian noise background of resonant gravitational antennas has been suggested. Gravitational data are processed in the inertialess nonlinear element--optimal linear filter--summator circuit.
Show AbstractThe effect of the granule size distribution on the percolation threshold in "metal-dielectric" granular alloys has been studied by numerical simulation. In the model alloy under consideration, metal granules have two characteristic dimensions, $l$ and $L$, $L>l$. The percolation threshold substantially increases as the $L/l$ ratio grows, both for the 2D and the 3D case, and tends to saturate at high $L/l$ values. The calculation results offer an explanation of high percolation thresholds observed for most granular alloys.
Show AbstractThe effect of illumination of microcrystalline hydrogenated silicon films lightdoped with boron on their electric and photoelectric parameters was studied. Changes in the conductivity and photoconductivity of films illuminated in dry air were observed. Illumination in a vacuum did not change the parameters of $p$-type films and decreased the conductivity of $n$-type films. Within the model based on the assumption that oxygen adsorbed by the films caused photoinduced parameter changes, the results were explained.
Show AbstractShifts of the fluorescence spectrum of dye molecules adsorbed in Langmuir- Blodgett ferroelectric films of polyvinylidene fluoride-trifluoroethylene copolymer were experimentally studied. The possible mechanisms of these phenomena were considered. Within the framework of the Landau theory, equations describing the temperature dependence of the position of fluorescence spectrum maxima of dye molecules incorporated into films was obtained. The experimental data agree well with theoretical estimates.
Show AbstractThe results of laboratory investigations into the structure of intense convective air vortices are discussed. The heat- and moisture-exchange mechanism responsible for the core diameter variation in vortices of the class under consideration is revealed.
Show AbstractA gravitational mechanism for the conversion of the energy of the expanding shell of a supernova into the energy of a star cluster is suggested. It is assumed that as long as the supernova shell continues to expand, it does not go beyond the cluster, and once its expansion has completely stopped, the shell material gets mixed with the interstellar material of the cluster. Thus, the gas does not leave the limits of the cluster, but the "bubbles" pulsating in it convert some of the supernova energy into mechanical energy of the stars. It is demonstrated that frequent supernova bursts in a dense cluster rich in gas (for example, in a galactic nucleus) provide for a substantial inflow of mechanical energy and can perceptibly affect the evolution of the cluster as a whole.
Show AbstractExamples of waveguides having trapping modes with a given natural frequency are given. The possibility of the existence of natural frequencies lying above the continuous spectrum lower boundary is proved.
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