Vernadsky Crimean Federal University
Vernadsky Crimean Federal University
Yatsenko A.V.,Vernadsky Crimean Federal University
Crystallography Reports | Year: 2017
Possible combinations of the electronic polarizability tensor components for oxygen and tantalum ions have been established based on the analysis of the refraction coefficients of LiТаO3 crystal in the far-IR region. The local electric field on structurally nonequivalent ions in the LiТаO3 unit cell was calculated within the modified point-multipole model. A combination of the electronic polarizability tensor components for oxygen and tantalum ions and their effective charges is established, which provides a good correspondence of the calculation results with the experimental data on LiТаO3 crystals obtained by 7Li nuclear magnetic resonance and 181Та nuclear quadrupole resonance and with the known value of the crystal spontaneous polarization. © 2017, Pleiades Publishing, Inc.
Lelyakov A.P.,Vernadsky Crimean Federal University |
Karpenko A.S.,Vernadsky Crimean Federal University
Theoretical and Mathematical Physics(Russian Federation) | Year: 2017
We consider the dynamics of a probe null string in the gravitational field of a closed (“thick”) null string radially collapsing in a plane. Analysis of the obtained solutions suggests that there might exist several properties of a null-string gas interesting from the cosmological standpoint, such as acceleration of expansion or contraction, a granular structure of the gas, the emergence of stable polarized states, and a domain structure. © 2017, Pleiades Publishing, Ltd.
Lelyakov A.P.,Vernadsky Crimean Federal University
Gravitation and Cosmology | Year: 2017
We have found a solution to the Einstein equations for the case of radial expansion or radial collapse of a multistring system having a layered structure. It has been shown that the influence of the gravitational field of such multistring system can lead to stable oscillations of a test null string in the vicinity of a fixed (stationary) point in space, which can be regarded as a spatially localized particle with a nonzero effective rest mass. In this case, the ability of multistring systems to create such particles can be considered as a possible alternative to the Higgs mechanism. It has also been noted that for a gas of null strings, creation of particles with nonzero effective rest mass is possible at early stages of the Universe evolution, where due to high pressures and a domain structure of such a gas, mutual penetration of null strings belonging to neighboring domains was unavoidable and could emerge in mass. At later stages, due to expansion of the Universe, such an opportunity could be lost. © 2017, Pleiades Publishing, Ltd.
Ergina E.I.,Vernadsky Crimean Federal University
Eurasian Soil Science | Year: 2017
Current approaches to the simulation of pedogenesis processes in time are considered. Models for the formation of humus horizon on parent rocks of different genesis in Crimea are presented. Formation rates of humus horizons have been determined, which allows developing the remediation strategies for mining dumps of mineral deposits in Crimea. © 2017, Pleiades Publishing, Ltd.
Kosmachev O.A.,Vernadsky Crimean Federal University |
Fridman Y.A.,Vernadsky Crimean Federal University |
Ivanov B.A.,Ukrainian Academy of Sciences
JETP Letters | Year: 2017
A phase diagram of a magnetic material with the spin S = 2 is obtained including all allowed spin invariants for the isotropic exchange interaction at an arbitrary relation between exchange constants. New phases with two-sublattice structure and biaxial symmetry at a site are found. © 2017, Pleiades Publishing, Inc.
Dzedolik I.V.,Vernadsky Crimean Federal University |
Pereskokov V.S.,Vernadsky Crimean Federal University
Atmospheric and Oceanic Optics | Year: 2017
TM modes of surface plasmon polaritons (SPP) can be excited on the surface of the metal layer of an adaptive mirror by an incident bulk electromagnetic wave. A part of the energy of the electromagnetic wave is involved in the excitation of SPP modes. E-modes of SPP are excited at reflection of TM modes from the boundaries of deformed regions on the adaptive mirror surface. The superposition of TM and E modes leads to generation of SPP vortices at singular points of the interference field. The topology of the SPP vortices changes depending on the curvature of the boundaries of deformed regions on the adaptive mirror surface. In this case, SPP vortices appear and disappear in the components of the Poynting vector, and the screw dislocations emerge at the mirror-reflected wavefront at the singular points of the field. Generation of SPP vortices on the metal mirror surface should be taken into account when calculating the wavefront correction parameters in adaptive systems. © 2017, Pleiades Publishing, Ltd.
Shostka N.V.,Vernadsky Crimean Federal University |
Ivanov M.O.,Vernadsky Crimean Federal University |
Shostka V.I.,Vernadsky Crimean Federal University
Technical Physics Letters | Year: 2016
A method of generating 3D optical trap arrays (OTAs) using a uniaxial crystal has been proposed and implemented. It is shown that the properties of obtained OTAs can be controlled by changing the parameters of the optical system and the state of radiation polarization past the crystal. © 2016, Pleiades Publishing, Ltd.
Netreba E.E.,Vernadsky Crimean Federal University
Journal of Structural Chemistry | Year: 2016
For the first time, a mononuclear biligand complex of lanthanum nitrate with bicyclic bisurea (4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione, or spirocarbon, Sk) [La(C11H20N4O2)2(H2O)2··(NO3)3] (I) is synthesized and its structure is determined by direct single crystal XRD. The crystals of I are monoclinic: space group P21/c, a = 11.1989(15) Å, b = 13.015(2) Å, c = 24.153(2) Å, β = 101.129(12)°, V = 3454.3(8) Å3, dcalc = 1.618 g/cm3, Z = 4, CCDC 985760. The structure is molecular. The lanthanum cation is coordinated by two oxygen atoms of two organic ligand molecules, two water molecules, and three bidentate nitrate anions. The coordination number of lanthanum is ten; the coordination polyhedron is an irregular 10-vertex polyhedron. The crystal of I represents a non-merohedral twin with the components turned by 180° along the a axis; the relative weights of the components are 0.76:0.24. To confirm the purity of the sample of I, the powder XRD pattern was refined using the Rietveld method; the unit cell parameters at room temperature are as follows: a = 11.2777(4) Å, b = 13.0774(5) Å, c = 24.3453(9) Å, β = 101.129(3)°, V = 3523.0(2) Å3. © 2016, Pleiades Publishing, Ltd.
Chuyan E.N.,Vernadsky Crimean Federal University |
Tribrat N.S.,Vernadsky Crimean Federal University
Human Physiology | Year: 2016
The effector function of sensory peptidergic perivascular fibers was examined upon multiple exposures to low-intensity millimeter electromagnetic waves by means of laser Doppler flowmetry. Low-intensity millimeter waves (wavelength, 7.1 mm; power density, 0.1 mW/cm2) were shown to increase the microcirculation index, which characterized the change in perfusion upon electrical stimulation, and to decrease the latency from the start of stimulation to the onset of vasodilation, pointing to an increase in the effector function of sensory peptidergic fibers and micruvascular reactivity. © 2016, Pleiades Publishing, Inc.
Kostandov Y.A.,Vernadsky Crimean Federal University
Journal of Mining Science | Year: 2016
The study is devoted to effect of contact friction on failure, ultimate stress and moduli of elasticity in rock specimens under compression. It is found that dependence of the listed characteristics on friction coefficient is incremental. The author reveals zones of full contact and slide. © 2016, Pleiades Publishing, Ltd.