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Search Results: 1 - 10 of 462488 matches for " Evgeny A. Rodionov "
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Nonstationary Wavelets Related to the Walsh Functions  [PDF]
Yuri A. Farkov, Evgeny A. Rodionov
American Journal of Computational Mathematics (AJCM) , 2012, DOI: 10.4236/ajcm.2012.22011
Abstract: Using the Walsh-Fourier transform, we give a construction of compactly supported nonstationary dyadic wavelets on the positive half-line. The masks of these wavelets are the Walsh polynomials defined by finite sets of parameters. Application to compression of fractal functions are also discussed.
Explicit solutions for partial differential equations of Lord-Shulman thermoelasticity
Rodionov A.
Theoretical and Applied Mechanics , 2009, DOI: 10.2298/tam0902137r
Abstract: We consider the Lord-Shulman model of thermoelasticity with one relaxation constant. The corresponding system of four linear partial differential equations is solved by means of holomorphic expansions. We prove the convergence of expansions and study the possibility to convert them in finite sums.
Stratospheric “wave hole” and interannual variations of the stratospheric circulation in late winter  [PDF]
Evgeny A. Jadin
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34033
Abstract: Using the monthly mean NCEP dataset, the analysis of the upward and downward propagation of planetary waves was conducted by means of the three-dimensional Eliassen-Palm (EP) fluxes in the stratosphere. It is shown that the upward/downward EP fluxes are observed in different regions of the atmosphere: their well- known upward propagation takes place over North Eurasia, while the downward one revealed over North Atlantic and Canada in a region of the so-called stratospheric “wave hole”. Generation of the downward wave signal may be associated with a reflection of planetary waves in the upper stratosphere. It is shown that the downward EP flux responsible for the sink of eddy energy from the stratosphere to the troposphere is important in late winter (January-February) for an understanding of the stra- tosphere-troposphere coupling on the interannual and decadal timescales, in particular the 11-year solar cycle influence on the stratosphere. Results presented can explain the unusual behavior of a few winters in the Arctic stratosphere, which are outlier from the known Labitzke, van Loon’s correlations of stratospheric parameters with the 11-year solar cycle under separation in the west/east phases of the equatorial quasi-biennial oscillation.
The Molecularly Fielding Psychophysical Nature of the Brain Mental Activity  [PDF]
Evgeny A. Yumatov
Neuroscience & Medicine (NM) , 2019, DOI: 10.4236/nm.2019.102004
Abstract: The brain is a unique organization in nature, having the psychic activity, which is expressed in subjective states: thoughts, feelings, emotions. Knowledge of the nature of mental activity of the brain is the most urgent and the most challenging task of physiology. Historically the neurophysiology developed on the basis of physical and chemical laws discovered in an inanimate nature. Our investigation is devoted towards the origin of a human subjective state, and presents a new methodology for studying of the nature psychic brain activity. We have established the existence of physical phenomena unique for the living brain so-called “psychogenic field”, which reflects the expressed psychic state of human brain. The subjective state of a human being was shown to affect remotely the physicochemical properties of the blood. An original schematic diagram is presented to describe the formation of the brain psychic activity. This approach is based on the feedback influence of a psychogenic field on neuronal molecular processes (self-induction in the brain). We propose a paradigm for the origin of psychic state and possible existence of the fields, which are unique for the brain. The presented scheme and paradigm of systemic organization of psychic activity of the brain are a prerequisite for the subsequent development of the theory consciousness.
Extensions and applications of the iterative method
S. A. Rodionov,E. Athanassoula
Physics , 2011, DOI: 10.1051/0004-6361/201116540
Abstract: Aims: We aim to develop an algorithm for constructing equilibrium initial conditions for simulations of disk galaxies with a triaxial halo and/or a gaseous component. This will pave the way for N-body simulations of realistic disk galaxies. Methods: We use the iterative method, which we presented in a previous article. The idea of this method is very simple. It relies on constrained evolution. Results: We develop an algorithm for constructing equilibrium models of disk galaxies including a gaseous disk and a triaxial or axisymmetric halo. We discuss two test models. The first model consists of a spherical halo, a stellar disk, and an isothermal gaseous disk. The second model consists of a triaxial halo, a stellar disk, and a star-forming gaseous disk. We demonstrate that both test models are very close to equilibrium, as we had intended.
Dynamical models of the elliptical galaxy NGC 4494
S. A. Rodionov,E. Athanassoula
Physics , 2010, DOI: 10.1111/j.1365-2966.2010.17429.x
Abstract: We present dynamical models of NGC 4494, which we built using our iterative method presented in a previous paper. These models are live N-body models consisting of equal mass particles, and they are steady state as confirmed by a fully self-consistent evolution. Our goals were twofold. The first one -- namely to test whether our iterative method could indeed be used to construct galactic models following given observational constraints, both photometric and kinematic -- was fully achieved. Our method allowed us to go beyond a simple spherical model and to make full sets of rotating, axisymmetric models without any limitations to the velocity distribution. Our second goal was to understand better the structure of NGC 4494, and more specifically to set constraints on its halo mass. For this we tried three families of models: without halo, with a light halo and with a heavy halo, respectively. Our models reproduce well the photometry and the kinematics, the latter except specific regions where some non-equilibrium or non-axisymmetric structure could be present in the galaxy (e.g. the kinematically decoupled core). However, the lower order moments of the velocity distribution (up to and including the second order) do not allow us to discriminate between the three halos. On the other hand, when we extend the comparison to the higher order moments of the velocity distribution obtained from the long-slit data, we find that our light halo model fits the data better than the no halo, or the heavy halo models. They also reproduce the shape of the angular dependence of the PNe velocity dispersion in the outermost parts of the galaxy, but not the amplitude of its azimuthal variation. This may imply that a yet more general class of models, such as triaxial, may be necessary for a yet better fit.
Programs for the work with ENSDF format files: Evaluator's editor EVE, Viewer for the nuclear level schemes
G. I. Shulyak,A. A. Rodionov
Physics , 2010,
Abstract: Tools for the regular work of the nuclear data evaluator are presented: the context-dependent editor EVE and the viewer for the level schemes of nuclei from ENSDF datasets. These programs may be used by everybody who works with the Evaluated Nuclear Structure Data File and for the educational purposed.
The ENSDF_toolbox program package: tool for the evaluator of nuclear data
G. I. Shulyak,A. A. Rodionov
Physics , 2010,
Abstract: The program package for the work with the Evaluated Nuclear Structure Data File is discussed. The program shell designed for the unification of the process of the evaluation of the nuclear data is proposed. This program shell may be used in the regular work of the nuclear data evaluator and for common use by scientists and engineers who need the actual data about nuclear states and transitions from the ENSDF database.
Mechanisms of the Vertical Secular Heating of a Stellar Disk
N. Ya. Sotnikova,S. A. Rodionov
Physics , 2003, DOI: 10.1134/1.1573281
Abstract: We investigate the nonlinear growth stages of bending instability in stellar disks with exponential radial density profiles.We found that the unstable modes are global (the wavelengths are larger than the disk scale lengths) and that the instability saturation level is much higher than that following from a linear criterion. The instability saturation time scales are of the order of one billion years or more. For this reason, the bending instability can play an important role in the secular heating of a stellar disk in the $z$ direction. In an extensive series of numerical $N$-body simulations with a high spatial resolution, we were able to scan in detail the space of key parameters (the initial disk thickness $z_0$, the Toomre parameter $Q$, and the ratio of dark halo mass to disk mass $M_{\rm h} / M_{\rm d}$). We revealed three distinct mechanisms of disk heating in the $z$ direction: bending instability of the entire disk, bending instability of the bar, and heating on vertical inhomogeneities in the distribution of stellar matter.
Bending instability in galactic discs. Advocacy of the linear theory
S. A. Rodionov,N. Ya. Sotnikova
Physics , 2013, DOI: 10.1093/mnras/stt1183
Abstract: We demonstrate that in N-body simulations of isolated disc galaxies there is numerical vertical heating which slowly increases the vertical velocity dispersion and the disc thickness. Even for models with over a million particles in a disc, this heating can be significant. Such an effect is just the same as in numerical experiments by Sellwood (2013). We also show that in a stellar disc, outside a boxy/peanut bulge, if it presents, the saturation level of the bending instability is rather close to the value predicted by the linear theory. We pay attention to the fact that the bending instability develops and decays very fast, so it couldn't play any role in secular vertical heating. However the bending instability defines the minimal value of the ratio between the vertical and radial velocity dispersions $\sigma_z / \sigma_R \approx 0.3$ (so indirectly the minimal thickness) which could have stellar discs in real galaxies. We demonstrate that observations confirm last statement.
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