The angular distribution and spectrum have been calculated for the lepton photodecay probability in a magnetic field. The study is made of how the probability is dependent on the field strength, lepton spin orientation, mass ratio of the initial and final leptons, and wave circular polarization direction.
Show AbstractQuantum limits have been found to the error in measuring the length of a rod, the coordinates of the ends, and the voltage at the end of a long line for various measurement methods. It is shown that the stroboscopic method of rod length measurement does not give an increase in sensitivity in a gravitational-wave experiment. The strobing method can be effective only in observation on one of the normal coordinates of the rod.
Show AbstractIt is shown that canonical perturbation theory enables one to calculate any radiation effects in classical electrodynamics in a unified fashion. The first part of the paper deals with spontaneous and induced emission from particles for a wide range of paths. The spectral and angular characteristics of the radiation have been determined. The second part of the paper derives expressions for the scattering cross sections of particles for electromagnetic waves in the presence of an external field. The results correspond to the crossed-field model.
Show AbstractAn expression is derived for the matter-field lagrangian in a proposed approach to the Kaluza-Klein theory. It is shown that the transformation features of these fields are equivalent to nonlinear realizations of the symmetry group.
Show AbstractSpectral analysis of the Schr$\stackrel{..}{o}$dinger operator for a multiparticle system provides conditions on the two-particle potentials such that if obeyed, a system of N particles has bound states of zero energy even though the subsystems of n particles, $n \subset \{N—1, N—2, ... 2\}$, do not have either bound or virtual states.
Show AbstractA thermal model is used to interpret experiments on probe-radiation reflection and second-harmonic generation SHG in reflection when a short laser pulse acts on GaAs. A formula is derived for SHG in reflection for the case where there is a layer of liquid of thickness d at the surface. Numerical calculations have been performed on the time dependence of d, the linear reflection coefficient, and the SHG for the probe radiation. There is good agreement between theory and experiment which supports the thermal model for laser annealing.
Show AbstractThe central-parameter method is applied to the energy range 25-1000 keV/nucleon to examine the formation of metastable helium-type and lithium-type ions during one-electron capture in the collision of light ions with helium atoms. Comparison with experiment shows that the model gives a qualitatively correct description of the cross section ratio for one-electron capture by ions in the ground state and in metastable states.
Show AbstractSystematic studies have been done on the differential and integral equilibrium spectra for electrons and photons in showers caused by primary electrons or photons. The spectra as functions of particle energy have been obtained by numerical solution of integral equations from the cascade theory with allowance for polarization, incomplete screening, the Compton effect, and the photoelectric effect. The accuracy has been examined for approximations such as neglecting the electrons rest mass and describing the ionization losses by means of an energy-differential term.
Show AbstractMeasurements have been made on the energies of cascades formed by primary cosmic-ray protons in a large emulsion stack exposed in the Interkosmos-6 satellite. Stack dimensions $60\times 20\times 40$ cm, exposure time 90 hr. The spectrum relates to the energy range 10-50 TeV and is compared with other experimental data.
Show AbstractMeasurements have been made on the energy spectra and on the longitudinal and transverse characteristics of haloes of electromagnetic nature observed in a deep lead chamber. It is shown to be possible to determine the energy of the primary particle and the height of the nuclear interaction responsible for the halo from the measured characteristics.
Show AbstractTheoretical and experimental determinations of the electron energy distribution for a positive-column plasma have been used with the published data for other heavy inert gases to show that at pressures $p\le 1$ Torr and low discharge currents, a substantial part is played in producing the low-energy part of the energy distributions in this xenon or other heavy inert-gas plasma by inelastic collisions between electrons and atoms, which leads to a Druvestein distribution for this energy range.
Show AbstractA perturbation method is used in a unified approach to the transformation of radiation spatial statistics in a nonlinear randomly inhomogeneous medium. Media with Kerr and thermal nonlinearities are considered with a given spectrum for the dielectric-constant fluctuations. Numerical calculations have been performed on the field-fluctuation variance and the correlation radius for partially coherent radiation.
Show AbstractMeasurements have been made on the parameters of a Fabry-Perot cavity surrounded by a metal shell, in which the radiation is extracted by diffraction. A study has been made of the effects of this shell on the major characteristics: transfer coefficient, natural-mode spectrum, field distribution, and quality factor. It is shown that the coupling holes in the mirrors tend to eliminate the degeneracy in certain mode types.
Show AbstractA resonator based on a segment of a transmission line is used as an intermediate circuit in a squid, with lumped reactive components at the ends, which enables one to raise the pumping frequency. Formulas are given that enable one to forecast and optimize the fluxmeter parameters, and results are presented on a device having an uncooled preamplifier at frequencies close to 40, 75, and 1000 MHz. An energy resolution of $1,6\cdot 10^{-28}$ J/Hz has been recorded at the upper pumping frequency.
Show AbstractA study has been made of the mean proportion of the energy lost by an electron in one collision in a positive discharge column for the vapors of sodium, potassium, rubidium, and cesium at $E/n_a = (2-20)\cdot 10^{-15} V\cdot cm^2$. The measured and calculated energy-loss factors agree satisfactorily. The main energy loss is due to inelastic collisions between electrons and atoms in the ground state and first excited one.
Show AbstractPath integration is used with the given-channel approximation to examine the propagation of a beam with random phase modulation in a medium having local and nonlocal nonlinearities. It has been found that the beam radius and the correlation radius vary in the same way. In the case of a self-focusing medium, an expression is obtained for the critical power for waveguide propagation.
Show AbstractSpontaneous parametric scattering has been used to determine the magnitude and dispersion of the absorption coefficient and the dispersion of the nonlinear susceptibility for crystals of iodic acid and deuteroiodic acid in the range 1200-5000 $cm^{-1}$. The spectrum structures are explained in terms of OH and OD vibrations, as well as numerous higher-order vibrations and Fermi resonance between them.
Show AbstractA study has been made of the spectral and polarization characteristics of dye luminescence in two-component solvents. It is shown to be possible to determine structures in binary solvents from the luminescence of dissolved dyes.
Show AbstractSimple theory is proposed to explain the observed multiple oscillations in the reflection and transmission coefficients for surface Rayleigh waves at the edge of an elastic wedge, which are dependent on the vertex angle.
Show AbstractMeasurements have been made on the spectra of the depolarized component of the Rayleigh scattering in the isotropic phase for two nematic liquid crystals; the temperature dependence of the anisotropy relaxation time $\tau$ has been derived. These $\tau$ data are compared with those from other sources, and it is concluded that the main contribution to the depolarized component comes from rapid rotation in the liquid-crystal molecules around their long axes.
Show AbstractResults are presented from laboratory experiments on the effects of surfactant films on regular and wind-induced waves. For all the substances, there is a resonant-type frequency dependence for the ratio of the wave damping coefficients on water coated with surfactant to that on pure water. The surfactant films attenuate the wave spectra considerably and reduce the rates of increase in the spectral components by comparison with those on pure water under the same conditions.
Show AbstractAn experiment has been performed on very long-range averaging over the temperature stratification to derive the spectrum of the atmospheric-pressure fluctuations as a power law with index $n \approx -1.7$. The dependence of $n$ on the parameter $\zeta = z/L$ is given for smaller but still large averaging scales.
Show AbstractIron ores from the Kumdykol deposit have been used to examine the mechanism responsible for the reverse residual magnetization, which is responsible for the negative magnetic anomalies over the deposit. Magnetic parameters have been determined that characterize the stability of the natural residual magnetization and the phase composition of the ferromagnetic fraction. The phase analysis has been based in particular on data on the hyperfine electron-nuclear interactions obtained by means of Mossbauer spectroscopy.
Show Abstract$Cd_xHg_{1-x}Te$ alloys with $x$ of 0.18-0.25 have been used in examining the voltage-current characteristics in fields up to 60 kOe at 4.2 K, while galvanomagnetic measurements have been made at 0.2-300 K. It is concluded that there is a nonmonotone dependence of the Hall coefficient on field at breakdown in materials with mixed conductivity, while the prebreakdown superlinear part of the voltage-current characteristic in a strong magnetic field is related to activation of electrons localized in potential wells.
Show AbstractMeasurements have been made on the mobility $\mu$ of ions on pyrolytic $SiO_2$ films at elevated humidity. It is found that $\mu$ is very much dependent on the $SiO_2$-film production temperature. It is considered that the main reason for this is increase in the microporositу as the pyrolysis temperature is reduced. It is concluded that the use of pyrolytic $SiO_2$ films as protective coatings will be effective only for sufficiently low degrees of microporosity.
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