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

## Foundations of possibility theory. Methods of optimal estimation and decision making. 1. Measure of Possibility: Definition and Properties

### Yu.P. Pyt'ev

Moscow University Physics Bulletin 1997. 52. N 3. P. 1

The paper presents a series of publications on the foundations of the possibility theory and its applications to mathematical modeling of reality on the basis of experimental data, knowledge and hypotheses of the researcher. In this work, the measure of possibilisty has been constructed and its properties have been considered.

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## Polarization in the $p\bar{p}\to e\bar{e}$ process and quasi-nuclear bound state

### V.A. Meshcheryakov, G.V. Meshcheryakov, Chan Kuang Tuet

Moscow University Physics Bulletin 1997. 52. N 3. P. 7

Earlier, the existence of a quasi-nuclear $p\bar{p}$ state with a low binding energy was suggested. The influence of this state on the electromagnetic form factor of the proton is discussed. Its contribution to the integral asymmetry of the $p\bar{p}\to e\bar{e}$ process has been calculated. Measuring the integral asymmetry even far from the $p\bar{p}$ reaction threshold was demonstrated to be important for detecting the quasi-nuclear state.

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## On interpretation of spin effects in Cerenkov radiation

### J.M. Ternov, A.V. Borisov

Moscow University Physics Bulletin 1997. 52. N 3. P. 10

Cerenkov radiation power depends on the correlation between electron polarization and photon helicity. This correlation is interpreted in the present paper as an interference between radiation amplitudes of the electron charge and the electron magnetic moment.

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## Investigation of optical properties of photographic emulsions by pulse optoacoustic method

### L.A. Aslanov, V.N. Zakharov, A.A. Karabutov, N.B. Podymova

Moscow University Physics Bulletin 1997. 52. N 3. P. 30

Absorption and scattering of light in photographic emulsions at the wavelength of the fundamental ($\lambda$ = 1.06 μm) and second ($\lambda$ = 0.53 μm) harmonics of an Nd:YAG laser are investigated with the help of the pulse optoacoustic method. It has been found that the light absorption factor is much smaller than the scattering factor, while the extinction coefficient and the light absorption factor for emulsions with different sensitivity are close. It has been shown that the influence of latent image on optical characteristics of photographic emulsions is small.

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## Electrothermal instability of oscillations in temperature-sensitive resonance systems

### G.V. Belokopytov

Moscow University Physics Bulletin 1997. 52. N 3. P. 15

A chain of equations describing the interaction of electromagnetic and thermal oscillations in systems with temperature-sensitive dielectrics in terms of coupled oscillators and relaxators has been obtained. The conditions of aperiodic and oscillatory instability have been determined and estimates of the threshold power of self-modulation excitation have been obtained for radio- and superhigh-frequency ferroelectric oscillatory systems and for optical-frequency microresonators such as fused quartz and water drops.

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## Theory of pulse NMR dept processes

### V.S. Tumanov

Moscow University Physics Bulletin 1997. 52. N 3. P. 21

The method of projection operators is applied to calculate pulse NMR experiments of the DEPT class taking into account the fine structure of the spectra and individual spin-spin coupling constants. The methodology of the theory of pulse processes is discussed.

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## Density restoration in the vicinity of a plane shock wave front by the shape of the schlieren signal

### V.I. Ivanov, G.I. Singaevskaya, E.N. Fomenko, F.V. Shugaev

Moscow University Physics Bulletin 1997. 52. N 3. P. 38

The schlieren method of studying density in the vicinity of a plane shock wave with consideration for the diffraction of a laser beam has been developed. An integral equation of the convolution type has been obtained for density, which is solved by means of Tikhonov's regularization method. The density restoration method proposed is employed for processing data obtained in the experiments with shock waves in the low temperature.plasma produced by an HF discharge in argon.

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Optics and spectroscopy

## Diagnostics of vibrational temperatures in $СО_2$ lasers by the gain of overlapping lines of different vibrational bands

### V.A. Spazhakin

Moscow University Physics Bulletin 1997. 52. N 3. P. 26

A method of determining vibrational temperatures of nonequilibrium carbon dioxide from the ratio of amplification (absorption) factors measured for overlapping lines of different vibrational bands has been developed and tested. Experiment has shown that the amplification of a number of vibration-rotational lines of "hot" bands overlapping the lines of the main laser transitions of $СO_2$ can be found from their contribution to the amplification of the main 10.4 and 9.4 μm band lines.

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Solid state physics

## $PrFe_5$ structure in $Pr-Fe$ system

### E.A. Rykova, N.A. Khatanova, A.S. Ilyushin

Moscow University Physics Bulletin 1997. 52. N 3. P. 43

The X-ray and electron diffraction studies show that following the stepwise annealing, 500 hours at 600°C + 30 hours at 800°C, an equilibrium $Pr_2Fe_{17}$ phase and the metastable phases, $\alpha –Рг$ and a $PrFe_5$ intermetallic compound of the $LuMn_5$ type which is a derivative of the Laves phases $MgZn_2 (С 14)$ are formed in the Pr-77 at.% Fe alloy. A scheme for rearranging $PrFe_5 (CaCu_5)$ into $PrFe_5 (LuMn_5)$ and $PrFe_5 (AuBe_5)$ has been given.

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## Short-range order in Fe-5 at.% Re alloy

### V.M. Silonov, L. Enkhtor

Moscow University Physics Bulletin 1997. 52. N 3. P. 49

The method of diffuse scattering of X-rays was used to establish the existence of a short-range order in the Fe-5 at. % Re alloy and to determine its parameters.

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## On the theory of superconductivity in high-temperature superconductors

### A.V. Vedyaev, A.M. Savchenko, A.V. Stefanovich

Moscow University Physics Bulletin 1997. 52. N 3. P. 52

Experimental approaches to estimating the parameter of resonance coupling between spin fluctuations and longitudinal phonons in superconducting copper oxides have been considered. Coupling parameter estimates were obtained based on bulk modulus $\lambda$ measurements. The result allows us to assert that the critical temperature of high-temperature superconductors can be increased to room temperature.

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## Low-frequency dielectric dispersion and pyroelectric effect in ferroelectric vinylidene fluoride-trifluoroethylene copolymer in phase transitions

### K.A. Verkhovskaya, N.D. Gavrilova, V.K. Novik, I.A. Malyshkina, T.B. Frolova

Moscow University Physics Bulletin 1997. 52. N 3. P. 55

The investigations of the dielectric constant, the pyroelectric coefficient and thermodepolarization currents both of a pure and a rhodamine-doped copolymer of vinylidene fluoride with trifluoroethylene (P(VF-TFE)) (70/30) have been carried out over a wide range of frequencies and temperatures. The temperature relationships obtained experimentally point to the reorganization of the structure of the amorphous phase of pure (P(VF-TFE)) in the temperature range of 313-323 K. The effect of doping on the specific feature of the copolymer has been studied.

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## Effect of crystallite size on optical spectra of diamond powders and polycrystalline films

### A.N. Obraztsov$^1$, T. Izumi$^2$, H. Okushi$^3$, H. Watanabe$^3$, I.Yu. Pavlovsky$^1$

Moscow University Physics Bulletin 1997. 52. N 3. P. 61

The present work submits the results of an investigation of diamond polycrystalline films, synthetic diamond powders and single crystals. Using photoacoustic spectroscopy, it was found that in the optical absorption spectra of all the three types of diamond materials studied there is a band corresponding to inter band absorption for quanta with energy exceeding 5.5 eV. For single-crystal samples an absorption band due to nitrogen impurities was detected and for polycrystalline films and powders there was observed a broad band due to structural defects. The specific feature of the spectra of films and powders is a strong light scattering in the ultraviolet region (250-300 nm), the efficiency of which increased with decrease of crystallite size from $\sim$100 to $\sim$1 μm. Further decrease of the size of diamond particles (down to 0.25 μm and less) diminished the share of scattered light because of the change of particles faceting and their coalescence.

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Geophysics

## Effect of water mass aeration on vertical temperature distribution in the near-the-water layer of the atmosphere

### E.P. Anisimova, S.N. Dikarev, A.A. Speranskaya, O.A. Speranskaya

Moscow University Physics Bulletin 1997. 52. N 3. P. 67

Experimental data on the vertical temperature distribution in a thin near-thewater air layer over aerated and nonaerated water have been reported. The heat flux from aerated water into the atmosphere, other conditions being equal, is higher than that from nonaerated water.

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## Effect of water surface pollution by petroleum products on the formation of Langmuir circulations and the energy exchange between a basin and the atmosphere

### N.S. Blokhina, A.E. Ordanovich

Moscow University Physics Bulletin 1997. 52. N 3. P. 71

A novel mathematical model is used for investigating the effect of oil pollutions on the characteristics of Langmuir circulations and the streams of sensitive and latent heat from a basin into the atmosphere. Calculations have been performed for a wide range of wind velocities over the basin and for the values of Dalton's number which depends on the surface pollution. A range of parameters in which the Langmuir circulations disappear has been found. Estimates have been made of the temperature differences between the water surface and the air, as well as between the water surface and the bottom, as functions of wind velocity and Dalton's number.

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## Experimental investigations of spatial structure of traveling ionospheric disturbances

### V.D. Gusev, A.G. Vologdin, D.V. Kiryanov

Moscow University Physics Bulletin 1997. 52. N 3. P. 77

A methodology is proposed for the solution of the inverse problem associated with experimental investigation of traveling ionospheric disturbances on oblique-incidence radiosonde observation on the ground.

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Atomic and nuclear physics

## On the kink in the energy spectrum of cosmic rays

### N.F. Gorshkov

Moscow University Physics Bulletin 1997. 52. N 3. P. 82

On the assumption that the motion of charged particles in cosmic rays (CR) is mainly determined by diffusion and the Lorentz force, estimates have been derived which show that the well-known kink in the CR energy spectrum at the energy $Е = З\cdot 10^{15}$ eV is due to a change in the character of turbulent motion in interstellar medium regions with nonuniform magnetic fields, whose scale is comparable with the thickness of the galactic disk. The application of the theories of similarity and dimensionality allowed us to describe qualitatively the experimentally observed CR energy spectrum in the kink's vicinity over the energy range of CR particles amounting to four orders of magnitude.

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Theoretical and mathematical physics

## Radiative shift of neutrino energy in a magnetized electron-positron gas

### P.A. Eminov, V.Yu. Grishina

Moscow University Physics Bulletin 1997. 52. N 3. P. 86

A radiative energy shift and an induced magnetic moment of a relativistic massive Dirac neutrino in a hot electron-positron plasma and in a degenerate electron gas in an external unquantizing magnetic field have been calculated.

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## Approximate calculation of Green's function for the Poisson equation on space $E _{D-2}\times V_2$

### Yu.V. Grats, A.B. Lavrent'ev

Moscow University Physics Bulletin 1997. 52. N 3. P. 89

The feasibility of approximately calculating the Green function for the Poisson equation on the space $E _{D-2}\times V_2$ and its regularized value in the limit of coinciding points is studied.

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## Still parametric solitons in periodically nonuniform media with quadratic nonlinearity

### S.V. Polyakov, A.P. Sukhorukov

Moscow University Physics Bulletin 1997. 52. N 3. P. 92

Equations have been derived for the envelopes of still parametric solitons at the fundamental and double frequencies in periodically nonuniform media. The integrals of motion have been obtained and the exact solution which describes the spatial distribution of vibrations has been found. The conditions of formation and the properties of still solitons have been analyzed.

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Solid state physics

## Hydrogen-induced nonequilibrium oscillating phase transitions in solid-state open Pd-Sm-H systems and Belousov-Zhabotinskii waves

### A.A. Katsnel'son, G.P. Revkevich, V.M. Avdyukhina

Moscow University Physics Bulletin 1997. 52. N 3. P. 96

New phenomena in nonequilibrium open Pd-Sm-H systems have been observed: as a result of saturation with hydrogen followed by degassing, a one-phase system transforms into a two-phase one, and the two-phase system, into the one-phase one. This indicates the occurrence of nonequilibrium oscillating phase transitions. According to the hypothesis suggested by the authors, the observed phenomena are explained by competition between ascending and gradient diffusion under substantially nonequilibrium conditions of the open solid-state system.

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