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Theoretical and mathematical physics

The numerical simulation of Faraday waves on the basis of hydrodynamic equations in the shallow-water approximation

The numerical simulation of Faraday waves on the basis of hydrodynamic equations in the shallow-water approximation

T.G. Elizarova$^1$, D.S. Saburin$^2$

Moscow University Physics Bulletin 2015. 70. N 1. P. 1

Faraday waves modeling in shallow water approximation was performed. Numerical algorithm was based on regularized shallow water equations. The obtained results are corresponding to existing analytical and experimental data, in particular, the parametric resonance for the first and for the second wave modes, which are, in accordance to the causing overload, regular and irregular waves, was observed

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Analysis of opaque objects images in optimization problem of automated focusing system

Analysis of opaque objects images in optimization problem of automated focusing system

A.I. Chulichkov, D.A.Popov

Moscow University Physics Bulletin 2015. 70. N 1. P. 7

The actual optimization problem of automated optical microscopy is considered. The approach, which analyzes characteristics of brightness of the Gaussian beam in the optical system of the microscope is proposed. Discrete (digital) model, correlating with continuous, is introduced. Analytical approach to finding the maximum of a discrete function representing the measure of the focusing optical system, is proposed. This approach requires a much smaller number of recorded images formed by the optical microscope. This speeds up the process of automatically focusing an optical microscope.

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Application of a two-dimensional model to describe the CO2 turbulent transfer in spatially non-uniform forest stand

Application of a two-dimensional model to describe the CO2 turbulent transfer in spatially non-uniform forest stand

Yu.V. Mukhartova, N.T. Levashova, A.V. Oltchev, N.E. Shapkina

Moscow University Physics Bulletin 2015. 70. N 1. P. 14

The numerical two-dimensional model of turbulent transfer of CO$_2$ in the air between a spatially non-uniform vegetation cover and the atmospheric surface layer was developed. The model is based on a one-and-a-half closure scheme for averaged equations of hydrodynamics and CO$_2$ diffusion in the air. The model was used to assess the possible influence of forest canopy heterogeneity on a CO$_2$ turbulent exchange in the atmospheric surface layer. CO$_2$ exchange was simulated at both the forest edge and within clear-cut area.

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Radiophysics, electronics, acoustics

Digital modulation type recognition using artificial neural network

Digital modulation type recognition using artificial neural network

S.S. Adjemov, M.V. Tereshonok, D.S. Chirov

Moscow University Physics Bulletin 2015. 70. N 1. P. 22

The report deals with results of artificial neural network usage for digital modulation type recognition. Usage of 2nd and 4th order cumulants as recognition features is proposed. Dividing features of high order cumulants differ for various modulation types. In practice the choice of signal features space (in this case – set of cumulants) and decision rules is performed by expert appraisal. Various researches show that the decision rules formation can be made using different methods of data mining, for instance, artificial neural networks. Usage of multiple layer perceptron as recognition device allows to automate the process of decision rules construction for digital modulation type recognition. The proposed technique provides high probability of correct recognition for such modulation types as FSK, ASK, PSK, QAM in absence of reference and clock synchronization. For instance, neural recognition technique supplies a correct recognition probability which is equal for FSK-2 = 0.99, for ASK = 0.98, for PSK-2 = 0.99, for PSK-4 = 0.7, for PSK-8 = 0.98, for QAM-16 = 0.86.

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Condensed matter physics

The dielectric response of triglycine selenate at frequencies of 0.07Hz-10MHz in the paraelectric phase

The dielectric response of triglycine selenate at frequencies of 0.07Hz-10MHz in the paraelectric phase

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

Moscow University Physics Bulletin 2015. 70. N 1. P. 28

The behavior of triglycine selenate single crystal in the paraelectric phase (above the phase transition temperature) was experimentally studied with the dielectric spectroscopy method in this work. The results of investigation of electrical properties were given in the frequency range from 0.07Hz to 10MHz and in the temperature interval from 7 to 70C. The presence of non-Debye spectrum type and linear dispersion that reveal in the paraelectric phase too was marked. One suggests that the linear dispersion is connected with proton multiposition hopping conductivity.

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Ballistic detection of weak signals using active Josephson media

Ballistic detection of weak signals using active Josephson media

N.V. Klenov, I.I. Soloviev, A.E. Shchegolev, A.L. Pankratov

Moscow University Physics Bulletin 2015. 70. N 1. P. 35

This paper examines the principles of operation of the ballistic detector in the presence of thermal fluctuations. We demonstrate the importance of considering the relativistic aspect when calculating both the dynamics of interaction of fluxons with current heterogeneity and the effect of fluctuations on this dynamics. We present the optimization of parameters of the detector (the value of the bias current and damping, geometrical parameters) in order to maximize the signal to noise ratio.

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Phenomenological description of entropy and heat capacity anomalies in lawsonite near phase transitions

Phenomenological description of entropy and heat capacity anomalies in lawsonite near phase transitions

S.V. Pavlov, R.A. Romanov

Moscow University Physics Bulletin 2015. 70. N 1. P. 42

The theoretical temperature dependences of the entropy and heat capacity near the phase transitions in considering the phenomenological model describing the sequence of phase transitions in the mineral lawsonite were calculated. Comparison of theoretical curves with the experimental results showed good qualitative agreement.

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Biophysics and medical physics

Interaction of helical structures as the molecular basis of intra-and intercellular interactions

Interaction of helical structures as the molecular basis of intra-and intercellular interactions

S.V. Stovbun, A.A. Skoblin, J.A. Litvin, M.G. Mikhaleva, V.A. Tverdislov

Moscow University Physics Bulletin 2015. 70. N 1. P. 45

It was identified two types of formation super spirals with the help of chiral biomimetics by sharing or counter spiral weave spiral molecular strings. Experimentally confirmed its earlier statement about the formation of homochiral molecular systems hierarchies supercoiled structures with alternating sign of chirality. In the development of the model of the Euler theory, estimates of forces and velocities in the systems of interacting spiral structures quantitatively relevant characteristic times and dimensions of the intracellular and intercellular interactions. It is shown that the phase of structure formation in the cell is not limiting, and the formation of intracellular structures is determined by the choice of the cell functional program. Keywords. Chirality, spirals, biomimetics, strings, molecular machines, biological cells interactions.

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Self-assembly of supramolecular homochiral structures in solutions of chiral biomimetics

Self-assembly of supramolecular homochiral structures in solutions of chiral biomimetics

S.V. Stovbun, A.M. Zanin, A.A. Skoblin, M.G. Mikhaleva, D.V. Zlenko, V.A. Tverdislov

Moscow University Physics Bulletin 2015. 70. N 1. P. 51

Detected and describes in the present study the phenomenon of formation of homochiral supramolecular sets of vortices in dilute xerogels chiral biomimetics TFAAS metrically similar and specific macromolecular biological macroscopic helical structures. Each vortex with a characteristic scale of ~ 1 mm corresponds approximately to the rotational symmetry groups Sn, depending on the number of strings that have a common binding or emerging from one of nucleation and experiencing mutually agreed evasion. It is essential that the deviation direction is reversed by changing the chirality of the enantiomer does not depend on the type of solvent. In various mixtures of chiral compounds is observed as a weakening and strengthening of this trend. The result is an important confirmation of the authors proposed a synergistic rule that when the sign of the chirality of basic monomers is changed to the opposite sign of the chirality of them formed supramolecular helix. Regularity of a fundamental nature and executed as a trend in the hierarchies of macromolecular structures of DNA, proteins, polysaccharides. Keywords. Biomimetics, chirality, enantiomers, trifluoroacetylated aminoalcohols, strings, and supramolecular helical vortices.

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Physics of Earth, atmosphere, and hydrosphere

On the existance of global electric circuit in the Mars atmosphere

On the existance of global electric circuit in the Mars atmosphere

A.A. Evtushenko, N.V. Ilin, F.A. Kuterin

Moscow University Physics Bulletin 2015. 70. N 1. P. 57

We consider main criteria’s for the formation and maintenance of the global electric circuit (GEC) in the atmospheres of planets in the Solar System. We estimate from the basic principles atmospheric conductivity profile and analyze the possible existence of GEC on Mars. Our model shows the absence of fixed GEC on Mars and possibility of current flow through the circuit from extended and powerful generator.

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Properties of residual deformation of ocean bottom by data of slip distribution for tsunamigenic earthquakes

Properties of residual deformation of ocean bottom by data of slip distribution for tsunamigenic earthquakes

A.V. Bolshakova$^1$, M.A. Nosov$^2$, S.V. Kolesov$^2$

Moscow University Physics Bulletin 2015. 70. N 1. P. 62

In this study we consider 75 ocean-bottom earthquakes occurred during the period 1923 – 2013. Making use of slip distribution data taken from the database SRCMOD and Okada formulae we calculated 200 models of co-seismic bottom deformation. Then we determine double amplitude of bottom deformation, displaced water volume and potential energy of initial elevation that is equal to ocean bottom displacement (tsunami energy). It is shown that, in the majority of cases, the horizontal components of bottom deformation provide an additional and noticeable contribution to the displaced water volume and tsunami energy. Relationships between the double amplitude, the displaced water volume, the energy of tsunami with and the moment magnitude of earthquake are analyzed; the corresponding regression dependences are constructed. It is shown that tsunami takes less than 0.1% of the earthquake energy.

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Estimation of parameters of the wave disturbances in the ionosphere by joint using GPS--interpheromrtry and vertical sounding data

Estimation of parameters of the wave disturbances in the ionosphere by joint using GPS--interpheromrtry and vertical sounding data

V.I. Zakharov A.F. Hamidullin

Moscow University Physics Bulletin 2015. 70. N 1. P. 68

In work the technique of the estimation of oscillatory speed amplitude, introduced in the ionosphere by wave disturbances of the various nature on the example of acousto gravitational waves is offered. The specified parameter characterizes the wave energy and is important for modelling energy exchang processes in the system of geospheres. Its definition has demanded using various ionospheric data – such as GPS- interpherometry and vertical sounding. Testing a method for an example of the data received during preparation and the earthquake in Athenes 2006г is lead. The technique supposes the using for estimations the data of IRI- model that appears practically comprehensible in quiet geo- and helio- physical conditions for an ionosphere in various regions (Arctic region, Asia, Africa, World ocean, etc.).

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