Faculty of Physics
M.V.Lomonosov Moscow State University
Theoretical and mathematical physics

## A model of nonideal bose gas. Phase transition and fountain effect

### V.P. Maslov

Moscow University Physics Bulletin 2003. 58. N 1. P. 1

A two-level model of a weakly nonideal Bose gas for a metastable (superfluid) state with pairwise interaction of the following type is considered: any pair of bosons (that happen to be) at the upper level give off a quantum of energy of the order of $1/N$, where $N$ is the number of particles. It is demonstrated that at a certain temperature a second-order phase transition with critical index $1/2$ and with fountain effect as a thermo-mechanical effect takes place.

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## Self-adjoint hamiltonian for massless scalar fields in the Schwarzschild space

### Ch. Aphantitis, S.V. Kalyashin

Moscow University Physics Bulletin 2003. 58. N 1. P. 5

It is shown that in the functional space defined in the paper, the radial operator of motion for a scalar massless field is self-adjoint with zero defect and doubly degenerate continuous spectrum in the exterior and interior regions of the Schwarzschild space.

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## Corrugation instability of a plane magnetohydrodynamic shock wave

### F.V. Shugaev, A.P. Kalinchenko

Moscow University Physics Bulletin 2003. 58. N 1. P. 11

Instability criterion of a plane magnetohydrodynamic shock wave is presented.

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## On parametric recognition algorithms

### E.A. Kirnos, Yu.P. Pytiev

Moscow University Physics Bulletin 2003. 58. N 1. P. 14

The authors have considered the effect of a training sample composition on the quality of pattern recognition in noise using the Kora, TEMP, R-method and CORAL algorithms. The algorithms are illustrated by the example of the problem of recognition of noisy black-and-white patterns and are compared with the algorithms of morphological analysis of gray-scale patterns [1, 2] and morphological analysis of Lambert objects [3]. This paper continues the research described in [4].

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## Orthogonal Galerkin method for solving the Helmholtz equation in a band with discontinuous not self-adjoint boundary conditions

### V.V. Konyushenko, V.P. Modenov

Moscow University Physics Bulletin 2003. 58. N 1. P. 18

A modified scheme of the Galerkin method, which takes into account the Meixner condition at a singular point, has been suggested for solving problems of electromagnetic waves resonance diffraction in a waveguide with discontinuous impedance boundary conditions.

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Atomic and nuclear physics

## Peculiarities of electromagnetic $\nu e$-scatterig of massive dirac neutrinos

### В.I. Goryachev

Moscow University Physics Bulletin 2003. 58. N 1. P. 22

It has been shown that electromagnetic $\nu e$-scattering caused by the anomalous magnetic moment of a massive neutrino $\mu_\nu$ does not make it possible to uniquely determine the value $\mu_\nu$ if the neutrino mass is unknown. The effective crosssection of such scattering coincides with scattering cross-section on the electron of a charged lepton without an anomalous magnetic moment but with effective electric charge $e_{\nu_{\rm eff}} < 10^{-9}e$. This result is interpreted as a consequence of structural effect associated with relativistic "tremor" of neutrinos. It has been shown that radiation processes can be neglected when massive neutrinos interact with matter.

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## Thermal radio-frequency radiation of disturbed surfaces

### A.I. Dubina, Yu.A. Pirogov

Moscow University Physics Bulletin 2003. 58. N 1. P. 27

Thermal radiation of a disturbed water surface is considered in a small-scale approximation. A method is presented for calculating the radiating power of a surface with an arbitrary number of surface waves based on the perturbation method and the Leontovich boundary conditions. A description and some results of the experimental check of this method are presented.

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Optics and spectroscopy

## Energy exchange of coherent light beams in azo-containing photosensitive polymers

### M.S. Andreeva, V.I. Shmalgauzen

Moscow University Physics Bulletin 2003. 58. N 1. P. 33

The paper has presented the derivation of equations for light-induced variation of the refractive index in an azo-containing polymer from balance equations for concentrations of trans- and cis-isomers of the azo dye. The equations thus obtained help us explain the two-exponential character of the relaxation characteristics of the refractive index. The frequency dependences of an additional term to the refractive index have been obtained for harmonic intensity modulation. At frequencies above resonance ones, the equations for two-wave interaction of coherent light beams in a polymer film coincide with those derived earlier on the basis of a phenomenological model.

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Solid state physics

## Two- and three-dimensional magnetic field diagrams of magnetization vector in thin magnetic films

### L.I. Antonov, E.V. Lukasheva, G.A. Mironova, D.G. Skachkov

Moscow University Physics Bulletin 2003. 58. N 1. P. 38

The ways of presenting graphically the equilibrium space distribution of magnetization vector and also the vortex and potential parts of this field are being analyzed. The procedure of visual graphic representation of a magnetic field has been developed for the two-dimensional periodic distribution of magnetization in a thin magnetic film. Magnetic films with anisotropy of the "easy-magnetization axis" type have been considered as an example.

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## Suppression of superconductivity in transition metal alloys

### A.I. Buzdin, A.V. Vedyaev, D.Yu. Gusakova, 0.A. Kotelnikova

Moscow University Physics Bulletin 2003. 58. N 1. P. 44

The authors study theoretically the effect of electron $s$-$d$ hybridization on the characteristic transition temperature to a superconducting state in transition metals. Calculations have been made in the Bardeen—Cooper—Schrieffer (BCS) model using the apparatus of the Green temperature functions. It is shown that the critical temperature reduces considerably in the case of $s$-$d$ hybridization of conduction electrons.

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## Temperature dependence of magnetic susceptibility of intermetallic compounds Ho$_x$Y$_{1-x}$Fe$_2$ ($x=0.1\div1$)

### Yu.I. Avksentiev, S.D. Antipov, G.E. Goryunov, I.R. Kamenskikh, D.V. Sadkov, P.N. Stetsenko

Moscow University Physics Bulletin 2003. 58. N 1. P. 49

The paper presents the results of experimental studies on the temperature dependence of the magnetic susceptibility of quasi-binary compounds Ho$_x$Y$_{1-x}$Fe$_2$ ($x=0.1\div1$) with the structure of the cubic Laves phase (C15) in the temperature range of 1.5—120 K. Differential magnetic susceptibility of samples containing Ho atoms was found to behave anomalously. Maximum susceptibility temperature at $x=0.28$ corresponds to the minimum magnetic moment per formula unit. A physical nature of such anomalies is discussed.

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Geophysics

## Features of seasonal variations and trends in surface ozone concentration at kislovodsk high-altitude research station

### 0.A. Tarasova, G.I. Kuznetsov, N.F. Elansky, I.A. Senik, I.A. Smetnik

Moscow University Physics Bulletin 2003. 58. N 1. P. 56

Based on the measurements of surface ozone concentration and weather parameters, the effect of relative humidity, percentile level and NО$_x$ accumulation level along the reverse paths of air mass transport on seasonal variations and trends of ozone was studied at the Kislovodsk high-altitude research station. The configuration of seasonal variation curves and trend values obtained for individual samples made it possible to describe qualitatively the contribution of different processes to variation of surface ozone. Analysis of the results has demonstrated that the contribution of photochemical processes to the surface ozone regime at the station is negligible. The empirical model of surface ozone concentration constructed with the use of weather parameters with due regard for seasonal variations helps in explaining up to 65% of ozone concentration variations.

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Astronomy

## Difference in modulation of anomalous and galactic cosmic rays in the 22nd solar cycle

### M.A. Kondratieva, Ch.A. Tretiakova

Moscow University Physics Bulletin 2003. 58. N 1. P. 63

The paper discusses the restoration of galactic cosmic rays intensity, which is more lengthy as compared with anomalous cosmic rays observed at the end of the 22nd solar cycle.

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## Anomalous behavior of velocity and attenuation of elastic waves in the electronic-topological transition domain in terbium

### A.V. Andrianov, A.A. Korobov

Moscow University Physics Bulletin 2003. 58. N 1. P. 66

The dependence of velocity and attenuation of elastic waves in terbium under uniaxial dilation has been studied experimentally. In the pressure range of 60 MPa, the anomalies of elastic properties typical of the electronic-topological transition have been discovered.

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Solid state physics

## Dynamic elastoplastic properties of copper wire under high strain

### A.I. Korobov, Yu.A. Brazhkin, Vang Ning

Moscow University Physics Bulletin 2003. 58. N 1. P. 69

This paper describes methods of excitation of large-amplitude elastic compression pulses and presents the results of experimental studies on the characteristics of their propagation in a copper wire. The pulse propagation velocity and the effective Young modulus were found to depend on the pulse amplitude.

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## Magnetic aftereffect observed in soft-magnetic nanocrystalline films on domain boundary oscillations

### V.E. Zubov, A.D. Kudakov, T.S. Fedulova, E.N. Sheftel', A.I. Krikunov

Moscow University Physics Bulletin 2003. 58. N 1. P. 72

The effect of dynamic defects on coercitivity of the domain boundary, surpassing the effect of static defects, was observed in soft-magnetic heterophase films on the basis of iron with high saturation induction by the magneto-optical method.

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