Mordovian State Pedagogical Institute

Saransk, Russia

Mordovian State Pedagogical Institute

Saransk, Russia

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Taktarov Dr. N.G.,Mordovian State Pedagogical Institute | Runova O.A.,Mordovian State Pedagogical Institute
PNRPU Mechanics Bulletin | Year: 2013

A mathematical model of waves propagation and instability on a surface of a cylindrical column of magnetic fluid of an infinite length, surrounding a coaxial infinite long porous core of the round section is constructed and studied. The conditions are found under which the disturbances of the surface of fluid column become unstable and result in its fragmentation into a chain of connected droplets. The presence of a surface tension is taken into account. The gravity is neglected. The axis of the porous cylinder coincides with the axis of a coaxial solenoid, generating an uniform magnetic field. The problem is solved in a cylindrical coordinate system (r, θ, z), in which the fluid column is at rest. The z-axis is directed along the axis of the solenoid. The equations of the motion of magnetic fluid inside and outside of the porous medium and the equations for the magnetic field are written. The boundary conditions for hydrodynamic and magnetic values on discontinuity surfaces are formulated. The disturbances of magnetic field (according to wave propagation) is searched inside and outside of the porous medium, as well as in the air clearance of the solenoid. The full solution of a boundary value problem for hydrodynamic and magnetic values is found. The numerical analysis of the dispersion equation, describing wave propagation on surface is done. The different special cases are considered. The conditions are found under which the disturbances of the surface of fluid column become stable (wave damping) or become unstable (which result to the disturbances growth and the fragmentation of the cylinder into a chain of droplets). It is shown that the size of droplets appearanced in fragmentation process increases with the growth of the magnetic field i.e. magnetic field has a stabilizing influence upon the fragmentation of the fluid column.


Malykhanov Yu.B.,Mordovian State Pedagogical Institute | Gorshunov M.V.,Mordovian State Pedagogical Institute | Evseev S.V.,Mordovian State Pedagogical Institute | Eremkin I.N.,Center for Professional Training
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2013

High-precision calculations of the ground-state energy of atoms He through Xe are performed in the algebraic approximation of the Hartree-Fock method. The orbital exponents of Slater-type basis functions are optimized using the second-order minimization methods, which allows the virial theorem to be fulfilled to within 10-15-10-17 for the first time. The energies of atoms calculated with rather limited basis sets are, in terms of accuracy, as good as the results obtained by using the numerical procedure for solving the Hartree-Fock equations. © 2013 Pleiades Publishing, Ltd.


Sveshnikov V.K.,Mordovian State Pedagogical Institute | Bazarkin A.F.,Mordovian State Pedagogical Institute
Applied Physics | Year: 2014

The article deals with the mathematical model of the oxide cathode, because ofeffects ofsodium. The methodology of calculation of the temperature dependence of the work function cathode barium sodium adsorption, which can be the basis for calculating the work function OK with a more complex structure of the emission coating.


Spiridonov S.N.,Mordovian State Pedagogical Institute | Sarychev V.S.,Galichya Gora Nature Reserve | Okolelov A.Y.,Michurinsk State Pedagogical Institute | Isakov G.N.,Chuvash State Pedagogical University | Sukharev E.A.,Moscow State Pedagogical University
Biology Bulletin | Year: 2011

The rare bird fauna of industrial wetlands has been studied in the forest-steppe zone of European Russia during the nesting period. A total of 146 species have been recorded, including 40 rare species listed in the regional Red Data Books. Facts of their nesting (in many cases, exceptional in the region) have been revealed. Evidence is presented for the significance of industrial wetlands for the conservation and propagation of rare bird species. © 2011 Pleiades Publishing, Ltd.


Sveshnikov V.K.,Mordovian State Pedagogical Institute | Vasilchenko V.G.,Mordovian State Pedagogical Institute
Applied Physics | Year: 2013

The article considers the operating principle and design of diffuse source of sodium ions on the basis of the discharge tube sodium lamps of high pressure type HPS-400. The generated source of sodium ions can find application in the technique of physical experiment, in prefabricated structures vacuum devices. It is simple in design, economical and allows time-vacuum degassing system.


Alyamkina E.A.,Mordovian State Pedagogical Institute | Yamashkin S.A.,Mordovian State Pedagogical Institute | Artayeva N.N.,Mordovian State Pedagogical Institute | Yurovskaya M.A.,Moscow State University
Moscow University Chemistry Bulletin | Year: 2010

The reaction of 4-amino-2-phenyl- and 4-amino-l-methyl-2-phenylindoles with a free β-position of the pyrrole ring with acetylacetone and dibenzoylmethane was studied. It was found that primary condensation occurs only on aminogroups and produces the corresponding enaminoketones, which under conditions of enamine acidic cyclization on the basis of dibenzoylmethane, turn into pyrrolo[2,3-h]-quinolines. The products of cyclization with participation of indole 3 atom were not detected. © 2010 Allerton Press, Inc.


Shorokhov A.V.,National Research Mordovian State University | Pyataev M.A.,National Research Mordovian State University | Khvastunov N.N.,Mordovian State Pedagogical Institute | Hyart T.,University of Jyväskylä | And 2 more authors.
JETP Letters | Year: 2015

In a superlattice placed in crossed static electric and magnetic fields, under certain conditions, the inversion of electron population can appear at which the average energy of electrons is above the middle of the mini-band and the effective mass of the electron is negative. This is the implementation of the negative effective mass amplifier and generator (NEMAG) in the superlattice. It can result in the amplification and generation of terahertz radiation even in the absence of negative differential conductivity. © 2014, Pleiades Publishing, Inc.

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