Faculty of Physics
M.V.Lomonosov Moscow State University

## Von Neumann algebras for arbitrary-spin fields

### D.G. Fedorov, S.S. Khoruzhii

Moscow University Physics Bulletin 1984. 39. N 6. P. 1

A modification of Khoruzhii's method is formulated for a system of Whiteman fields of arbitrary spin, which enables one to use the modular Tomita-Takesaki theory to put the Whiteman fields into correspondence with local von Neumann field algebras without imposing additional conditions on the fields. This provides a network of von Neumann algebras for fields of any spin that satisfies all the axioms in the algebraic approach, including the axiom of locality in the generalized form of locality with torsion.

Show Abstract

## Effects of collisions of the second kind between electrons and excited atoms on the electron energy distribution in an inert-gas plasma

### A.P. Ershov, A.A. Kuzovnikov

Moscow University Physics Bulletin 1984. 39. N 6. P. 5

A numerical solution to the kinetic equation is used to consider the effects of collisions of the second kind between electrons and excited atoms on the electron energy distribution and the rates of inelastic processes in a stationary neon-xenon plasma. The effects become substantial at values of the reduced electric field E/p of the order of tenths of a $V\cdot cm^{-1} \cdot Torr^{-1}$ and degrees of ionization $p<10^{-6}$ if the over-all concentration of the atoms in the lower excited levels exceeds the electron concentration.

Show Abstract

## Photoconductivity and photo-EMF under relaxation conditions. Part 2

### Yu.P. Drozhdov

Moscow University Physics Bulletin 1984. 39. N 6. P. 10

A simple model is considered that provides a qualitative explanation of the intensity and temperature dependence of the photocurrent observed for various materials.

Show Abstract

## The Hamiltonian forms of some integration methods

### Yu.G. Pavlenko

Moscow University Physics Bulletin 1984. 39. N 6. P. 16

Three integration methods are considered in Hamiltonian form: the rapidly rotating phase method, generalization of the Newton-Kantorovich method for arbitrary systems, and Fock's fifth-parameter method, which opens up a new approach to integrating Maxwell's equations.

Show Abstract

## An experimental check on the thermalization conditions for an electron flux after exposure to a UHF field

### M.N. Devyatkov, G.I. D'yakonov, G.I. Ovchinnikova

Moscow University Physics Bulletin 1984. 39. N 6. P. 23

Temperature measurements are reported for an electron flux exposed to a UHF field and passing through a dense space-charge region. It is shown that certain combinations of UHF frequency and current density cause the perturbation to be transformed into electron heating. The experimental results confirm previous theoretical estimates for the flux thermalization conditions.

Show Abstract

## The roles of various relaxation mechanisms in the nonlinear spectroscopy of condensed media

### V.M. Petnikova, S.A. Pleshanov, V.V. Shuvalov

Moscow University Physics Bulletin 1984. 39. N 6. P. 27

A study is made on nonlinear-spectroscopy methods that employ resonant parametric interactions on one-photon electron transitions. A model for the nonlinear. susceptibility is constructed that incorporates several types of relaxation. It is shown that these can be distinguished and identified by experiment.

Show Abstract

## Frequency-selective action on nonlinear waves in an acoustic cavity

### V.E. Gusev

Moscow University Physics Bulletin 1984. 39. N 6. P. 33

A mathematical technique has been developed for analyzing the excitation and interaction of nonlinear waves in an acoustic resonator with complex dissipative behavior. It is shown that it is possible to raise the quality factor by introducing additional absorption at selected frequencies.

Show Abstract

## A colored-fermion triplet in the field of a polarized Yang-Mills wave

### V.R. Khalilov, V.C. Perez-Fernandez

Moscow University Physics Bulletin 1984. 39. N 6. P. 39

An exact solution has been derived to Dirac's equation in a plane-wave Yang-Mills field of special configuration.

Show Abstract

## Features of the thermal and dynamic structures of the active ocean layer in the region of banks

### M.B. Timonov, N.K. Shelkovnikov

Moscow University Physics Bulletin 1984. 39. N 6. P. 44

Results are presented on the dynamic and thermal structures of the active ocean layer in the regions of the Ampere and Whale Banks, which were obtained on the eleventh voyage of the R/V Academician Petrovskii. The field observations indicate that there are regions above the crests of the bank that differ substantially from the surrounding water masses in thermal and dynamic characteristics. The features are given a qualitative explanation in terms of Taylor's column theory.

Show Abstract

## Kinetic cooling in a binary molecular-gas mixture with two-quantum vibrational energy exchange

### U.S. Dzhurabekov, A.I. Osipov

Moscow University Physics Bulletin 1984. 39. N 6. P. 49

Calculations have been performed on the kinetic cooling effect in a binary mixture of molecular gases on two-quantum vibrational-energy exchange between the components. It is shown that this effect can be detected by experiment for $CH_3F-N_2$ and $СН_4-О_2$ mixtures, which enables one to determine the probabilities of two-quantum vibrational-energy exchange.

Show Abstract

## Laser diagnosis of nonstationary protoplasm flow in algal cells on membrane stimulation

### E.B. Chernyaeva

Moscow University Physics Bulletin 1984. 39. N 6. P. 53

A study has been made of the effects of external conditions on the flow recovery in the protoplasm of Nitella algae after a halt produced by membrane excitation. The protoplasm flow speed has been measured with a laser Doppler spectrometer working with a US-1010 computer in real time. It has been found that under otherwise constant conditions, the recovery kinetics may be determined by the parameters of the stimulating pulse and the illumination conditions.

Show Abstract

## Dye picosecond pulse generation with self-modulated Q switching

### V.M. Petnikova, S.A. Pleshanov, V.V. Shuvalov

Moscow University Physics Bulletin 1984. 39. N 6. P. 60

A study has been made of picosecond pulse generation by dye lasers working with heavy gain saturation. Several forms of such laser are proposed that differ in reliability and design. Wide-range adjustment is possible in pulse length and spectrum. Spectrum-bounded pulses of length down to 3.5 psec have been obtained.

Show Abstract

## The accuracy in potential recovery in an inverse scattering problem ($l\ge 1$)

### G.A. Ivanov, A.M. Popova

Moscow University Physics Bulletin 1984. 39. N 6. P. 63

The paper discusses the error in recovering potentials within the framework of exactly soluble quantum models for the case ($l\ge 1$). It is shown that even for $l=1$, one can obtain reliable information on the behavior of the potential in this way only at large distances.

Show Abstract

## Extracting the beam from a high-energy cyclotron via an integer resonance

### L.A. Sarkisyan

Moscow University Physics Bulletin 1984. 39. N 6. P. 66

It is shown to be possible to provide highly efficient beam extraction from cyclotrons of pion and kaon factory type by means of an integer-resonance mechanism: on account of the closed-orbit distortion in the zone of an integer resonance before it occurs. Numerical simulation results are given on proton extraction from a cyclotron on the basis of the resonance $Q_r=2$.

Show Abstract

## Frequency dispersion in the capacitance of a Schottky barrier on amorphous hydrogenated silicon

### R.V. Prudnikov, A.P. Gus'kov, V.O. Abramov

Moscow University Physics Bulletin 1984. 39. N 6. P. 69

A dispersion-model has been used for the level charge-reversal times to calculate the frequency-dispersion curves for the capacitance of a Schottky barrier on amorphous hydrogenated silicon. A comparison is made with experiment, and it is shown that the model explains the experimental results satisfactorily.

Show Abstract

## X-Ray diffraction in a finite crystal with linear lattice-constant variation

### A.V. Kolpakov, V.I. Punegov

Moscow University Physics Bulletin 1984. 39. N 6. P. 73

The dynamic theory of X-ray diffraction is considered for a crystal of finite thickness with linear variation in the lattice period for the Bragg case. There is shown to be an analogy between X-ray diffraction in such a crystal and light diffraction at a slit in the Fresnel case.

Show Abstract

## Preferred nuclear orientation arising in beta decay in a steady magnetic field

### V.N. Rodionov, I.M. Ternov, O.F. Dorofeev

Moscow University Physics Bulletin 1984. 39. N 6. P. 76

A preferred spin orientation is shown to occur in nuclei arising from beta decay in a strong steady magnetic field. A study is made of the conditions under which the proton polarization in the reaction $n \to p+e+\bar{\nu}$ is close to 100%.

Show Abstract

## Mixing of the $2S_{1/2}$ and $2P_{1/2}$ levels in hydrogen

### V.V. Starshenko, R.N. Faustov

Moscow University Physics Bulletin 1984. 39. N 6. P. 79

A calculation is performed on proton-recoil effects in the mixing of the $2S_{1/2}$ and $2P_{1/2}$ levels in hydrogen due to the weak interaction.

Show Abstract

## The charge on nickel oxide in electron-stimulated neutral molecule desorption

### G.G. Fedorov, V.F. Vasil'ev

Moscow University Physics Bulletin 1984. 39. N 6. P. 82

A study has been made of the charging mechanism for nickel oxide in electron-stimulated neutral-molecule desorption. It has been found that the charging is not related either to the electron-stimulated desorption of positive ions or to the trapping of the bombarding electrons at traps in the surface. A charging mechanism is proposed.

Show Abstract

## The propagation of sound in a vibrationally nonequilibrium gas

### A.I. Osipov, A.V. Uvarov

Moscow University Physics Bulletin 1984. 39. N 6. P. 85

A dispersion equation is derived for the propagation of sound in a nonequilibrium vibrationally excited gas with allowance for the pumping and heat loss; the condition for sound amplification is derived. Numerical estimates are made that indicate that the effect should be observable.

Show Abstract

## One-parameter equations in describing average-velocity profiles for turbulent flows of weak polymer solutions

### V.P. Petrov, V.I. Sugrei, Yu.L. Shchev'ev

Moscow University Physics Bulletin 1984. 39. N 6. P. 89

Introducing a weak polymer solution into a flowing liquid reduces the resistance coefficient, thickens the viscous sublayer, and increases the velocity gradients. To describe the average-velocity profile in a turbulent flow, one can use one-parameter equations in which the adjustable constants in the logarithmic distributions for the average velocities are expressed in terms of the thickness of the viscous sublayer in the transitional region and the turbulent core, that thickness being $2/\kappa$ where $\kappa$ is the Karman parameter.

Show Abstract

## The relation between the even photomagnetic effect and the photo-Hall effect

### V.I. Nikolaev, G.N. Sever, T.V. Shilova

Moscow University Physics Bulletin 1984. 39. N 6. P. 93

The paper discusses the scope for using the even photomagnetic effect PME in examining the properties of semiconductor materials in cases where one usually employs the photo-Hall PH effect. One of the components of the even PME involves the same mechanism as the PH, and therefore similar information is provided by the even PME and PH regarding the properties of the semiconductor material. This is confirmed by measurements on the even PME and PH, and also on the odd PME in the same geometry for p-type Ge and Si.

Show Abstract