Faculty of Physics
M.V.Lomonosov Moscow State University

## Vector-phase methods and the development of advanced new-generation acoustic systems

### V.A. Gordienko$^1$, T.V. Gordienko$^1$, N.V. Krasnopistzev$^2$, V.N. Nekrasov$^2$

Moscow University Physics Bulletin 2014. 69. N 2. P. 105

The results of theoretical and experimental studies are discussed aiming at the justification of potential vector-phase methods for various hydroacoustics applications. These studies have greatly contributed to the active introduction of the vector-phase methods for sonar measurements. The advantages of vector-phase methods, especially in underwater acoustics are most manifested at significant limitation of the spatial region for their propagation in the medium. A qualitative shift exists in the case of a single combined receiving module (CRM), which provides a new “characteristic” of the point receiving system, viz., detectability of the acoustic source. Another CRM feature is the applicability of a fundamentally new (as concerns hydrophone systems) processing algorithm based on direct measurement of acoustic flux (energy), i.e., the release of its part that is dependent on field anisotropy or point sources in the environment.

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Theoretical and mathematical physics

## Verification of a mathematical model that describes the action of uranium hexafluoride on the human body in facilities of the atomic industry

### S.P. Babenko$^1$, A.V. Bad’in$^2$

Moscow University Physics Bulletin 2014. 69. N 2. P. 124

A complex mathematical model that describes the action on the human body of uranium hexafluoride that enters the air of the work space in facilities of the atomic industry is considered. Partial models that describe the pollution of the work space and percutaneous and inhalation entries of toxic substances to the body are discussed. Initial equations are presented and basic experimental premises are considered. The choice of several important parameters of the complex model is discussed. The predictions of the model are compared with known experimental results.

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## A parameterized equation of state for the region between the critical and supercritical isotherms and the interaction potential

### P.N. Nikolaev

Moscow University Physics Bulletin 2014. 69. N 2. P. 134

A parameterized equation of state is suggested. It describes a part of the phase diagram in the region between the critical and supercritical isotherms up to densities equal to the critical density, within the experimental error. It is shown that this requires data on the position of the critical point and the second virial coefficient. The applicability of two-parameter potentials to description of this region is analyzed.

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## Induced current and transmission through the barrier in the four-fermion model in 2+1 dimensions

### V.Ch. Zhukovsky, E.A. Stepanov

Moscow University Physics Bulletin 2014. 69. N 2. P. 139

A three-dimensional theoretical model with compactification of the third dimension in the presence of a four-fermion interaction under the A 3 external gauge field, where the mass was generated in a two-dimensional brane, has been considered. In the framework of this model the appearance of an induced current was predicted. The induced current was obtained as the function of the flux of Aharonov-Bohm field. The resulting expression oscillates with frequency, depending on the value of the flux. In the absence of compactification, the transmission coefficient through the delta-shaped barrier that was formed by the four-fermion interaction was obtained.

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## The singular points and phase diagram of the supercritical region of a substance

### P.N. Nikolaev

Moscow University Physics Bulletin 2014. 69. N 2. P. 146

This paper suggests using the supercritical point and the maximum fluctuation point on the supercritical isotherm for the analysis of the behavior of various substances in the vicinity of the critical point. These three points lie at the vertices of a triangle that is formed by the supercritical isotherm, the line of the local minima of stability, and the line of maxima of fluctuations. In this triangle, which is called supercritical, the fluctuations and instability behave such that this part of the phase surface is most interesting from the viewpoint of performing various chemical reactions. Here, large fluctuations and the stability of the system rapidly decrease with increasing volume. This region is studied in the approximation of the van der Waals and Van Laar equations.

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Physics of nuclei and elementary particles

## Evaluation of fully integrated ${\gamma_v p\rightarrow \pi^+ \pi^- p}$ cross sections in the resonance region at photon virtualities 5 < Q$^2$ < 12 GeV$^2$

### V. Burkert$^1$, E.N. Golovatch$^2$, E.L. Isupov$^2$, B.S. Ishkhanov$^{2,3}$, V.I. Mokeev$^{1,2}$, G.V. Petrun’kin$^3$, J.A. Skorodumina$^3$, G.V. Fedotov$^4$

Moscow University Physics Bulletin 2014. 69. N 2. P. 152

Evaluation of fully integrated double pion electroproduction cross sections of protons was carried out at $1.4<W<2.0 GeV$, $5<Q^2<12 GeV^2$. The cross-section evaluation was obtained from an approach based on extrapolation of the double pion component of inclusive structure functions $F_1$ and $F_2$ from photon virtualities $Q^2<5 GeV^2$ towards $5<Q^2<12 GeV^2$. $Q^2$-parameterization compatible with restrictions from the Operator Product Expansion was used to conduct the extrapolation. The results will be used to extract double pion electroproduction cross sections of protons in future experiments with the new CLAS12 detector.

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## The biological effectiveness of X-ray radiation

### A.V. Belousov$^1$, U.A. Bliznyuk$^2$, P.Yu. Borschegovskaya$^1$, A.S. Osipov$^1$

Moscow University Physics Bulletin 2014. 69. N 2. P. 157

Using Monte Carlo simulation, this paper explores the passing of gamma radiation through biological thin layers. In radiobiological experiments, this method of investigation simulates the conditions for determining the relative biological effectiveness (RBE). X-ray spectra from X-ray tubes, which are often used in such experiments, are simulated in this paper. The RBE is determined as the ratio of absorption doses, when the number of ionization events is equal for gamma and X-ray radiation. The results of the estimates are represented for the modeling of X-ray spectra in the case of irradiation of biological layers of different thicknesses.

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## Methods for solving the system of nonlinear oscillation equations that determine the gravitational constant

### V.M. Shakhparonov

Moscow University Physics Bulletin 2014. 69. N 2. P. 162

Methods for solving a system of nonlinear oscillation equations are discussed. The perspective for functional enhancement of existing methods for determining the gravitational constant, $G$, at an aspheric configuration of interacting bodies was demonstrated. A paper that was presented in $DAN SSSR$, 245, N3 (1979) is analyzed. The dependence of the $G$ value on the position of attracting masses may be explained by the paramagnetic effect. Its mass point imitation, which defines its value and position, resulted in the standard $G$ value.

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Condensed matter physics

## Variation in the structural state of the $\alpha$-phase in the Pd-In-H system during the $\alpha\rightarrow\beta$ transformation

### V.M. Avdyukhina, O.V. Akimova, I.S. Levin, G.P. Revkevich

Moscow University Physics Bulletin 2014. 69. N 2. P. 169

Increasing the concentration of indium atoms and hydrogen was found in the $\alpha$-phase of the foil of a Pd-In alloy (with 5.3 and 5.0 at % In) after its electrolytic hydrogenation and 500-h relaxation. It is shown that the structural variations in the foil during the $\alpha\rightarrow\beta$ transformation are nonmonotonic.

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## Dynamics of relaxation processes in a triglycine selenate single crystal in a ferroelectric phase

### A.V. Vorobyev, N.D. Gavrilova, A.M. Lotonov

Moscow University Physics Bulletin 2014. 69. N 2. P. 175

The deviation of the relaxation spectrum from the Debye type is studied experimentally and the presence of the non-Debye relaxation is shown, which is defined in different temperature ranges either by proton multiposition transitions below the Curie point T$_С$ or relaxation domain and interphase boundaries in the vicinity of T$_С$. For triglycine selenate, the methods of analysis of dielectric non-Debye spectra are used.

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## Investigation of the photoelectronic properties of nanocrystalline carbon- and nitrogen-doped titanium dioxide

### E.A. Konstantinova, N.T. Le, P.K. Kashkarov, A.A. Zaytseva, V.G. Kytin

Moscow University Physics Bulletin 2014. 69. N 2. P. 180

This paper reports the results of the study of photoelectronic properties of nanocrystalline titanium dioxide doped with carbon and nitrogen. Photo-generated paramagnetic radicals were detected and identified in nanocrystalline titanium dioxide by the electron paramagnetic-resonance method. The concentrations of the radicals versus the carbon and oxygen content were determined in the dark and under light exposure. The presence of C- and CO$^{-}_{2}$-radicals in carbon-doped titanium dioxide and mainly N and NO radicals in nitrogen-doped titanium dioxide is shown. The concentration of the radicals increases under light exposure, which indicates the recharging processes of electronic states in the bandgap, due to the presence of a dopant, accompanied by generation of paramagnetic particles. The electron paramagnetic resonance data correlate with the kinetics of formaldehyde decomposition on the titanium dioxide samples under study.

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Chemical physics, physical kinetics, and plasma physics

## The influence of RF plasma treatment at low pressure on the permeability of a polyurethane nanocomposite

### I.Sh. Abdullin$^1$, V.S. Zheltukhin$^2$, I.A. Borodaev$^2$, E.V. Strebkov$^2$, A.A. Khubatkhuzin$^1$

Moscow University Physics Bulletin 2014. 69. N 2. P. 185

The statistical model of treatment of a polyurethane nanocomposite by low-energy ionic streams in RF plasma at pressure in the range 13.3–133 Pa is developed. The dependence of the permeability of a filled nanocomposite on the filler mass fraction, both before and after RF plasma treatment, is theoretically investigated.

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Biophysics and medical physics

## Some features of sensing by cochlear neurons of low-frequency signals

### V.A. Gordienko$^1$, T.V. Gordienko$^1$, S.S. Zadorozhnyi$^1$, S.A. Isaychev$^2$, A.V. Uchaev$^2$, M.A. Amosov$^1$

Moscow University Physics Bulletin 2014. 69. N 2. P. 190

Some features of sensing by human cochlear neurons of the infrasound vibrations generated by a change in frequency and volume of the audible range are discussed. It has been shown that auditory neurons respond to a volume envelope that selects corresponding infrasonic frequencies for their further processing. This mechanism is possible if the ear operates nonlinearly performing detection with further time averaging of no less than over 40–50 ms. If the frequency of the sound code coincides with any rhythm of the brain, resonance may occur, increasing the amplitude of the corresponding rhythm.

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Physics of Earth, atmosphere, and hydrosphere

## Orthogonal functions of turbulent fluctuations in the Earth’s atmosphere

### V.P. Yushkov, E.V. Yushkov

Moscow University Physics Bulletin 2014. 69. N 2. P. 199

A system of orthogonal functions is suggested, which allows a statistically optimal description of turbulent fluctuations of the spatial density of the distribution function of identical Lagrangian air particles.

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