Faculty of Physics
M.V.Lomonosov Moscow State University
Astronomy, astrophysics, and cosmology

## Modern cosmology: Facts and ideas

### A.M. Cherepashchuk, A.D. Chernin

Moscow University Physics Bulletin 2008. 63. N 5. P. 299

A brief overview of the main observational facts and key ideas of modern cosmology is given. It is emphasized that present-day cosmology is a fundamental science about the evolution of the Universe based on verified empirical data and a reliable physical theory.

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Theoretical and mathematical physics

## Generalized quantum measurements of continuous variables

Moscow University Physics Bulletin 2008. 63. N 5. P. 315

The general concept of generalized quantum measurements with minimal distortion of initial information, which was introduced in our earlier publication [1] is applied to the problem of continuous quantum variables measurement. The qualitative features of such measurements are revealed and compared with a standard completely dequantizing measurement, which is described by the corresponding positive-definite operator-valued measure.

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Physics of nuclei and elementary particles

## Formation of the ${}^{178m2}$Hf isomer in a natural mixture of hafnium isotopes irradiated by an intense $\gamma$ quantum beam (experiment)

### V.A. Bocharov, I.G. Goncharov, A.N. Dovbnya, S.S. Kandybei, V.I. Noga, Yu.N. Ranyuk, O S. Shevchenko

Moscow University Physics Bulletin 2008. 63. N 5. P. 321

The results of an experiment on the production of the ${}^{178m2}$Hf isotope by exposing a natural mixture of hafnium isotopes to an intense bremsstrahlung beam are reported. The sample under investigation was exposed to an electron beam with an energy of 30 MeV and current 200 μ A for 500 h. The spectrometric analysis of the irradiated sample using radiochemical methods for the separation of isotopes did not reveal ${}^{178m2}$Hf lines.

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## Application of local negative feedbacks for active suppression of scattering and intrinsic radiation fields of a body

### S.G. Mikhailov

Moscow University Physics Bulletin 2008. 63. N 5. P. 329

We theoretically show the possibility of reducing the scattering and intrinsic radiation fields of a body when using an active suppression system that includes a layer of monopole radiators that cover its surface and to which a local negative velocity (acceleration) or pressure feedback on the outer surface is applied. The radiators are controlled by signals from the receivers located on an additional outer surface. We have carried out an experiment that confirms the derived relations for the one-dimensional case of intrinsic radiation field suppression.

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## Amplitude fluctuations of a plane wave in a random medium with regular refraction in the Markov-process approximation

### O.K. Vlasova, L.I. Prikhod’ko

Moscow University Physics Bulletin 2008. 63. N 5. P. 333

The fluctuations of a ray vector and the wave amplitude along the ray in a random medium with regular refraction are considered in a geometric-optics approximation. The solution of the problem is based on the description of the scattering process by Langevin-type stochastic dynamic equations. Under the assumption that the correlation radius of dielectric permittivity fluctuations is small compared with the distance passed by a ray, one can consider scattering as a Markov process and pass from dynamic equations to the Einstein-Fokker equation [1]. A solution to the Einstein-Fokker equation is given by the probability density function of the wave amplitude along the ray.

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## Investigation of oscillation regimes for a modified Carnot engine: I. Conservative oscillation regimes

### A.N. Zaikin

Moscow University Physics Bulletin 2008. 63. N 5. P. 339

The Carnot engine, the model from which the concept of entropy arose, is a parametric generator. A certain modification of the engine has allowed it to be brought into the periodic regime of a stable limit cycle. A formula identical to the expression for the oscillation frequency of a Helmholtz resonator has been derived for the piston oscillation frequency in a quasi-harmonic small-amplitude regime. The shape of the piston oscillations and the form of the phase trajectories are considered in computer simulations for various initial conditions and large amplitudes.

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## Investigation of oscillation regimes for a modified Carnot engine: II. The Carnot engine is a parametric generator of self-sustained oscillations

### A.N. Zaikin

Moscow University Physics Bulletin 2008. 63. N 5. P. 344

The periodic regime of a stable limit cycle for a modified Carnot engine is realized through an algorithmic slide valve. The power, piston oscillation frequency, and efficiency of the engine have been determined in a quasi-harmonic approximation. The modified engine can operate in the regime of a triangular limit cycle (cycles with any number of angles larger than three are realizable). The developed approach to analyzing the dynamic regimes of a Carnot engine allows one to dispense with the concept of entropy.

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## Dielectrometry of liquid media using a piezoelectric resonator

### Yu.K. Aleshin, A.P. Sukhorukov, I.A. Sukhanov

Moscow University Physics Bulletin 2008. 63. N 5. P. 349

A technique for measuring the permittivity coefficient of liquids based on the dependence of a piezoelectric resonator on ambient conditions is suggested. A model of a resonator, which allowed calculating its resonance frequency with the permittivity of the ambient liquid, is presented. Theoretical calculations are in good agreement with the experimental data. The dependence of the permittivity coefficient of an “ethyl alcohol-water” system on the concentration of components is determined with the given technique.

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Optics and spectroscopy. Laser physics

## Magnetic resonance signals from the optically oriented two-level spin system in the presence of nonresonant fields

### S.D. Petrova, R.M. Umarkhodzhaev

Moscow University Physics Bulletin 2008. 63. N 5. P. 353

A theoretical and experimental investigation into the motion of the magnetization vector in the presence of two additional circularly-polarized nonresonant rf fields, when these fields rotate in the plane analogous to that of resonant rf fields with the frequency $\omega$, has been performed. The nonresonant fields are equal in magnitude; their frequencies differ from the resonant frequency $\omega$ by the value of $\pm\Omega$, which essentially exceeds the magnetic resonance line width.

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Physics of nuclei and elementary particles

## Change of primary cosmic ray mass composition at superhigh energies

### N.N. Kalmykov$^1$, Jorge Cotzomi$^2$, V.P. Sulakov$^1$, Yu.A. Fomin$^1$

Moscow University Physics Bulletin 2008. 63. N 5. P. 359

The EAS MSU array experimental data are analyzed in relation to the primary cosmic ray composition in the energy range above 10$^{17}$–10$^{18}$ eV. The problem of the existence of an additional cosmic ray component, which cannot be explained in the framework of traditional mechanism of Galactic cosmic ray production, is considered. The fraction of gamma-quanta in the primary cosmic radiation is evaluated as well.

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Optics and spectroscopy. Laser physics

## Investigation of optical inhomogeneities of multilayered reflecting coatings with high spatial resolution

### I.A. Bilenko, E.S. Gromova

Moscow University Physics Bulletin 2008. 63. N 5. P. 362

An original method for the diagnostics of reflecting coatings is proposed. This method is applied to the investigation of multilayered mirrors used in laser gravitational antennas. The possible influence of the detected defects on the sensitivity of antennas is discussed.

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Chemical physics, physical kinetics, and plasma physics

## Surface microwave discharge in high-speed air-hydrocarbon flows

### A.F. Aleksandrov, V.M. Shibkov, L.V. Shibkova

Moscow University Physics Bulletin 2008. 63. N 5. P. 365

The influence of nonequilibrium plasma of the surface microwave discharge on the ignition of supersonic (${M=2}$) propane-air flow, as well as alcohol, benzene, and kerosene for sub- and supersonic air flow is studied.

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Biophysics and medical physics

## Specific features of interaction of ionogenic surface-active substance with $\kappa$-carrageenan

### T.E. Grigor’ev, D.V. Kolesov, E.E. Makhaeva, I.V. Yaminskii, A.R. Khokhlov

Moscow University Physics Bulletin 2008. 63. N 5. P. 367

Atomic force microscopy was used for the investigation of local lattices of $\kappa$-carrageenan adsorbed on a surface in the presence of an ionogenic surface-active substance. The effective binding of the surface-active substance by helical and native forms of carrageenan is demonstrated.

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