The influence of the nickel content on the induced absorption, radioluminescence, and thermoluminescence of ruby crystals heat treated in different redox conditions is investigated. It is established that electron-hole traps belonging to nickel form a closed system with respect to traps due to chromium in the course of steady irradiation. From the viewpoint of the band structure of the solid, an interpretation of the given phenomena is offered.
Show AbstractA generalization of the well-known Snyder apprpach to quantum space is developed. The problem of the hydrogen atom in discrete space is considered. Energy-level values of a hydrogen-like atom with characteristic corrections required by the discreteness of space are obtained.
Show AbstractThe results of experimental investigation of the flow-velocity field in the region of an autonomous riparian current usually existing in forward channel flows are presented. A physical model of the formation of the liquid boundary separating the riparian current from the basic flow is proposed.
Show AbstractThe Hall and Nernst-Ettinghausen effects and the electrical resistivity in nickel and cupronickel alloys with a Cu concentration of 4.6-30 wt.% are investigated in the temperature range from 78 K to the Curie temperature. On the basis of the data obtained on the magnitude and sign of the anomalous Hall and Nernst-Ettinghausen constants, the basic type of carriers of the anomalous Hall current in the alloys is determined. It is shown that variation in the given effects with concentration is associated with the state density of the d band.
Show AbstractOn the basis of the analysis of experimental data, the equations of a binodal $\omega=\pm B\theta^{0,323}+(B-1)\theta$ and a spinodal $\omega=\pm B \frac{2-l}{l}\theta^{0,323}+(B-1)\theta$ are obtained, where $\omega=\rho/\rho_k-1,\theta=1-T/T_k$; the plus sign refers to the liquid branch and the minus sign to the vapor branch. The value of l is universal and close to 1.20; B is an individual characteristic. New variables characterizing the remoteness of the state of the material at temperature T and density $\rho$ relative to the spinodal and the "rectilinear-diameter" line, $\omega = (B-1)\theta$, are introduced. In the new variables $\tau = \frac{l}{2-l}[\omega+(B-1)\tau], X=\tau+|Y|^{1/0,323}$ where $\tau=-\theta$, the spinodal converts to the axis Y, the "rectilineardiameter" line to the axis X; the binodal and critical isotherm are shown by symmetric curves. For the region adjacent to the spinodal, an equation of state is proposed: $\pi-\pi_c = \Pi YX^{1,26}$, where $\pi=\rho/\rho_k$; $\pi_c$ is the reduced pressure at the spinodal (for $\theta>0$) or the pressure at Y = 0 (for $\theta<0$). This equation describes the singularity of the compressibility at the spinodal and at the critical point, and ensures the calculation of the PVT relations in the metastable region, at the binodal, and in the adjacent regions of state.
Show AbstractThe temperature relaxation of stimulated local cathode luminescence in GaN:Zn is investigated. Two rates of relaxation are observed. The two relaxation times and the corresponding activation energies are found. The storage time of the activated state in the temperature range 0-l00°C is estimated.
Show AbstractIn the low-energy approximation of the Weinberg-Salam model, an accurate expression is obtained for the probability of electron-positron pair formation by a neutrino in a constant crossed field. Asymptotes are obtained for the case of high and low initial neutrino energies.
Show AbstractThe structure and chemical composition of Gd-Fe films obtained in a discharge with oscillating electrons in Kr are investigated. The films are of thickness 0.6-5.5 μm. It is shown that films applied in plasma discharge conditions ($\rho_{Kr}=5\cdot 10^{-4}$ mm Hg) are amorphous, whereas films obtained in low-pressure discharge conditions ($\rho_{Kr}=2\cdot 10^{-4}$ mm Hg) are amorphous-crystalline, with crystalline oxide inclusions. The change in structure and chemical composition of the films on prolonged storage in the atmosphere is investigated.
Show AbstractThe form of the ultrasonic waves of finite amplitude in a bounded beam is investigated experimentally. Asymmetric distortion of the compression and rarefaction phases due to diffractional divergence of the wave is observed. The variation in degree of asymmetry of the profile with distance is found to be nonmonotonic. The wave profiles recorded practically coincide with those obtained earlier by numerical calculation.
Show AbstractExperimental results on the formation of currents in an annular rotating cuvette heated from below are given. It is shown that vertical convective cycles induce horizontal flow along the axis of the annular cuvette. Trajectories of the motion of liquid particles are constructed for two rates of rotation. The results of the investigation are of interest for an understanding of the mechanisms of current flow in geophysical processes.
Show AbstractThe total and partial cross sections of resonant photoionization of helium in the region between the second and third thresholds are calculated using the method of interacting configurations in complex-number representation. In the calculation, account is taken of the interaction of four configurations of open channels and 20 configurations of closed channels. The curves and characteristics of the resonances obtained are compared, where possible, with existing experimental data.
Show AbstractIt is shown that a parametric loop with discontinuous capacity modulation has two stable states, which are determined by initial conditions and are characterized by different signs of the instantaneous values of the oscillations at a fixed moment of time. These properties are analogous to phase quantization of parametric oscillations approximated by a single harmonic tone in parametric generators and nonlinear waveguide systems. Expressions are obtained for determining the spectral composition of the oscillations excited. Experimental spectra for the ninth and tenth excitation regions are given. It is shown that phase quantization occurs for each of the harmonic components of the oscillations.
Show AbstractIt is shown that, in conditions of depolarization of resonant light in optically dense mercury vapor, processes of atomic orientation may be described by approximate equations coinciding in form with the Bloch equations.
Show AbstractThe mean magnetic moments $\bar{\mu}$ and M$\stackrel{..}{o}$ssbauer spectra of binary and ternary alloys $Fe_{75}(Cr_x Co_{1-x})_{25}$ are measured at room temperature. The additivity of the contributions of Cr and Co atoms in the first two coordination spheres to the effective hyperfine-interaction field at the nuclei of Fe atoms is shown. The contributions of the magnetic moments of individual atoms $\mu_{Fe}$, $\mu_{Cr}$ and $\mu_{Co}$ to the mean magnetic moment at an atom of the alloy are estimated. It is shown that the magnetic moment of Cr atoms is antiparallel to the magnetization vector of the sample.
Show AbstractThe fluctuations in the field of the Stokes component of induced Raman scattering (IRS) with a characteristic time determined by the spectral width of the phonon wave excited in the medium were found. The fluctuations are observed in IRS in compressed hydrogen and liquid nitrogen using both narrow-band and broad-band pumping. A system consisting of a single-mode ruby laser and an amplifier is used to excite the IRS. Depending on the method of Q-factor modulation of the laser, the spectral width of pumping may be about 0.01 or 0.3-0.5 $cm^{-1}$. The characteristic time $\tau$ of the fluctuations in hydrogen at pressures of 40 and 20 atm is found to be 2.3 and 4.3 nsec, respectively; the value in liquid nitrogen is 4.5 nsec. Theoretical consideration of the effect leads to the conclusion that, in conditions of reproduction and manipulation of the pumping wavefront, the fluctuations occur synchronously in the beam cross section, while the IRS field with spatially coherent pumping is spatially coherent. Good agreement of the theoretical and experimental values of $\tau$ is observed.
Show AbstractA method of determining the nitrogen concentration in epitaxial layers of gallium phosphide is described; the method is based on measuring the ratio of photoluminescent intensity of the lines A and A-LO and the radiative time of the A line at T=80 K.
Show AbstractA method is proposed for calculating the characteristics of multilayer interference systems under the action of a radio pulse with an arbitrary envelope. The method is based on recurrence relations between the field amplitudes in the layers of the system. Results of numerical experiment for the example of a multilayer absorber are given.
Show AbstractAn expression for the contribution to the effective Lagrangian of an electromagnetic field due to the polarization of the vacuum of Weinberg-Salam charged vector bosons by a strong magnetic field is obtained and investigated. It is shown that, within the framework of the linear approximation of the Weinberg-Salam model, there is a threshold of $W^{\pm}$-boson pair creation in a magnetic field.
Show AbstractThe Hartree-Fock method with a frozen core is used to calculate the excited $^1P(3d^9nf)$ states (n = 4,5,6) in the isoelectronic series of Xe with continuous variation in nuclear charge in the range $53.9 \le Z \le 55.1$. The singularities in the behavior of the single-particle energies and mean radii of the excited nf levels in the collapse of 4f electrons are investigated, the parameters of the transition region are determined, and the resonance of the levels is discussed in detail. It is shown that, within the framework of the method employed, the 4f level in the $Cs^+$ ion collapses, which corresponds to experimental data on photoabsorption.
Show AbstractA modified scheme is described for a parametric phase quantizer with radio-pulse pumping, allowing near-limiting sensitivity and speed of action of the AC quantizer to be achieved. The scheme employs balancing of variable and constant potentials and Q-factor modulation of a loop, as well as pulse selection in the phase detector.
Show AbstractFor the example of ethanolic and glycerine solutions of benzocarbolin it is shown that in liquid solutions of organic compounds in individual solvents, translational transitions of solvent molecules in the solvate shells of the solute molecules may lead to the presence of spectral inhomogeneity of the medium with respect to processes of steady luminescence and migration of the electron-excitation energy over impurity centers, which appears in the form of a long-wave concentrational shift of the luminescence spectra in the absence of physicochemical conversions of the molecules in solution.
Show AbstractThe evolution of the self-oscillation spectra in the region of stochasticity in the parameter space of the system is investigated numerically. It is shown that, moving deeper into "chaos", the spectrum approaches a continuous form, while close to the boundary of the stochasticity region it is close to a line spectrum.
Show AbstractOn the basis of the qualitative analysis of the equations of motion of a test body, new estimates are obtained for the accuracy of measuring the components of a non-Abelian gage field. They generalize the result of [l] on the measurability of the electromagnetic field to the case of an arbitrary gage group.
Show AbstractA two-loop scalar diagram basic to the calculation of high-order Feynman diagrams is calculated.
Show AbstractThe three-frequency interaction of diffracting light pulses is numerically analyzed. It is shown that taking account of diffraction leads to a complex space-time structure of the radiation: division of the pulse occurs, with the formation of an annular structure of the pumping beam.
Show AbstractThe process of nonlinear amplification of the curvature of the profile of an intense acoustic pulse and the formation of a shock wave in a solid is observed for the first time. A new method of measuring nonlinear elastic moduli is realized.
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