R e g u l a r p a p e r s

Theoretical and mathematical physics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 5

Classical gravitational effects (light beam deflection, time lad of radio signals, and displacement of the pericenter of a satellite's orbit) in the field of a Kerr-Newman source are considered in the relativistic theory of gravitation. Exact expressions for the magnitudes of the effects and their post-Newtonian asymptotic forms are obtained.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 10

The contribution of leading diagrams with Higgs bosons to the form factors of a vertex $ее\gamma$ and to the anomalous magnetic moment of an electron in a magnetic field $В$ is calculated in a single-loop approximation. It is noted that for $B\to 0$ the diagram with an electron loop yields a zero result. For $В = 0$ and $M\sim 6$ GeV, the contribution of the Higgs diagram, which is topologically identical to a diagram of quantum electrodynamics, is equivalent by the order of magnitude to the contribution of the six-loop quantum electrodynamics diagrams.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 15

A method has been proposed for constructing the resonance localization regions of helium-like ions. The upper estimate for the resonance halfwidths in the system has been derived. Resonances in helium-like ions are shown to be accumulated at real thresholds.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 19

The process of production of charmed particles in a proton-proton collision is considered. The results of analytical computer calculations of the cross section for the main subprocess, namely, the gluon-gluon production of a charmed quark pair, are presented. It is shown that the main contribution to the cross section is provided by third order perturbation theory diagrams.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 23

The motion of binary systems consisting of self-gravitating bodies of comparable masses is examined within the framework of an extended version of the parametrized post-Newtonian formalism. It is shown that the dynamic characteristics of moving bodies significantly depend on a new parameter $\tau$. A possible method of evaluating this parameter in treating the observation data obtained from the study of the pulsar system PSR 1913+16 is discussed.

Show AbstractRadiophysics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 27

A numerical study of the role of nonlinear effects in plasma in the course of development of beam-plasma instability in a waveguide is followed by an analysis of the field and the beam density perturbations, and the soliton-like plasma produced during this process. A quantitative criterion of applicability of a linear (in terms of plasma electrons) approximation to the theory of beam-plasma interactions is derived.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 32

Analysis of spatial resolution in a scanning electron microscopy study of semiconductors in the local cathodoluminescence mode has been made on the basis of electron trajectory simulation by the Monte Carlo method. A high spatial resolution is shown to be attainable at accelerating voltages of 10 to 20 kV. The experimental results obtained during the cathodoluminescence study of n-GaP are in agreement with the computed values of spatial resolution.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 38

Inherent noises in low-frequency modulation-type seismic sensors have been investigated. Algorithms for the optimum digital filtration of the output signal have been developed. A formula to calculate the noise factor for random flicker noise parameters is presented.

Show AbstractOptics and spectroscopy

Moscow University Physics Bulletin 1990. **45**. N 2. P. 43

A dynamic model of the four-photon response is proposed to interpret the dispersion relations obtained by biharmonic pumping in the range of interband absorption in gallium selenide. The intraband electron-phonon relaxation processes are described in the adiabatic approximation, with the phonon subsystem divided into the coherent active and the noise relaxation parts. The model proposed allows a qualitative description of experimental data.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 49

Collinear interaction of two high-power randomly-polarized wades of different frequencies in nonlinear gyrotropic media has been examined. The potentialities of a spectroscopic investigation of the associated polarization effects offer much greater efficiency as compared to the spectroscopy of nonlinear optical activity.

Show AbstractAcoustics and molecular physics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 53

Changes of dielectric loss, electrical conductivity, heat transfer coefficient, and supercooling are found in bidstilled water exposed to a weak variable magnetic field. The magnetic field affects charged protons, proton-containing groups in water, and their nuclear spins, inducing changes in the transition probabilities of these particles in the chains of the Bernal-Fowler hydrogen bonds. A prolonged exposure to the field results in structural changes of the hydrogen bond network. The newly-formed quasi-equilibrium macroscopic state of water takes a very long time (hours) to relax to the initial state.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 59

The mutual correlation functions of pressure pulsations on the surface of a cylinder passed around by water flowing at an 0.5 m/s velocity are studied experimentally. It is shown that in the case of two small-size sensors spaced apart along the incident flow, the mutual correlation of pressure pulsations decreases exponentially. A law for approximating the experimental data is proposed and a difference from the planar case is demonstrated.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 63

A procedure for the physical modeling of the two-dimensional inverse scalar scattering problems studied in computer-aided diffraction tomography (CDT) is discussed and an experimental set-up designed for such a modeling is described. The reduction of a three-dimensional inverse problem to a two-dimensional one is achieved by using the regime of single-mode propagation of an acoustic wave in a flat waveguide. Various data acquisition schemes for the particular CDT reconstruction algorithms are suggested and discussed.

Show AbstractAstronomy

Moscow University Physics Bulletin 1990. **45**. N 2. P. 66

The behavior of nuclear matter is considered from the standpoint of the discovery of six-quarks. The results are applied to calculations of parameters of neutron stars. It is shown that the maximum masses and radii of neutron stars decrease and that there may exist ultrahigh-density objects of very small masses. A new mechanism is proposed to explain explosions of supernovae of the first type. It is demonstrated that in the process of collapse a star passes through a stage of instability leading to an explosive release of energy.

Show AbstractSolid state physics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 70

Consideration is given to a theoretical model of the initial stages of the primary processes of photosynthesis. A Master Equation system consisting of three equations is used. The solution, which has been obtained using the Laplace transform, describes the kinetics of recombination fluorescence as a sum of decaying exponents. The relation between the fluorescence parameters and the rate constants of transitions between the states of the system has been obtained.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 74

The surface of layered alumosilicates catalyzes the process of iron aggregation. At the first stage, the clay minerals adsorb $Fe^{3+}$ ions from the solution. Subsequently, under the influence of the surface subjected to various external factors, these ions aggregate into $[Fe_2^{3+}(OH)_2^-]^{4+}$ dimers and, at the next stage, they form polymeric films with a hydroxide-like structure. Under low pressures ($\sim10^7 Pa$) and under of influence of direct current, the ions and the dimers undergo the transition $Fe^{3+}\to Fe^{2+}$.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 78

Difficulties encountered in solving problems of solid state physics with the aid of the Kramers-Kronig relations are analyzed. The application of the fast Fourier transform is shown to reduce considerably the computation time. Criteria are derived for the evaluation of the accuracy of the computation results. The major sources of error in the numerical calculations with these relations are analysed.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 83

A phenomenological model is proposed to describe phase transitions in ferroelectric alums. It is shown that the anomaly of the dielectric constant in MASD at 145 К is due to a phase transition in the field of spontaneous polarization which takes place as a result of the interaction between collinear dipole subsystems. Some peculiarities in the behavoir of the dielectric constants of alums under the influence of external factors are explained.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 87

It is shown that the injection of electrons from silicon into the oxide and the irradiation with electrons lead to similar changes in the energy spectra of the surface states and to an increase in the change instability $Si—SiO_2$-metal structure irrespective of the type of conductivity of the silicon substrate. The charge instability that arises is due to generation of mobile ions and slow electron states in the oxide. The character of the energy spectrum of the surface states depends on conditions of electron injection.

Show AbstractB r i e f r e p o r t s

Radiophysics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 92

Complex controlled spectra of self-sustained oscillations are shown to be producible in stabilized multiresonator oscillators driven by an external harmonic force. The form of the spectra is related to the detuning of the external force frequencies relative to the oscillator's natural frequencies.

Show AbstractGeophysics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 95

It is shown that the mechanism of nitric oxide (NO) formation in the middle atmosphere involving the excited particles $N(^2D)$ and $N_2(A^3 \Sigma _n +)$ is indeed capable of producing the high NO concentrations actually observed in auroras and a substantial decrease of the mesospheric ozone concentration.

Show AbstractSolid state physics

Moscow University Physics Bulletin 1990. **45**. N 2. P. 98

The problem of selecting refrigerants for magnetic refrigerators operated within wide temperature intervals has been considered. The criteria proposed allowed the determination of rareearth metals and alloys which are promising refrigerants for magnetic cooling machines operated within the 20-77 К and 77-300 К temperature intervals.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 101

A method has been developed for the calculation of diffraction patterns from a single crystal with second-phase precipitates. The method allows the determination of the lattice parameters, the Bravais lattice type, and the orientation relations between the matrix and precipitation phase lattice from the coordinates of reflections on the X-ray diffraction and electron microdiffraction patterns.

Show AbstractMoscow University Physics Bulletin 1990. **45**. N 2. P. 104

X-ray diffraction methods have been used to study the $\beta$-phase content as a function of the time of palladium saturation with hydrogen. The $\beta$-phase content growth rates are different in regions with different crystallographic orientations. An increase in the saturation time can stabilize the $\beta$-phase.

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