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201.
E Glushkov N Glushkova A Eremin R Lammering M Neumann 《The Journal of the Acoustical Society of America》2012,132(2):EL119-EL124
Lamb wave propagation in fiber-reinforced composite plates is featured by a pronounced directivity of wave energy transfer along the fibers from a point surface source. In the case of non-point (sized) source, the main lobe of radiation diagram may turn with frequency up to the orthogonal to the fibers direction. This effect has been theoretically studied and physically explained in the context of semi-analytical integral-equation based mathematical model. The present paper gives its experimental verification. 相似文献
202.
The magnetic properties of trigonal Nd0.9Dy0.1Fe3(BO3)4 substituted compound with the competitive Nd-Fe and Dy-Fe exchange interactions have been investigated. It has been shown that in Nd0.9Dy0.1Fe3(BO3)4 a spontaneous spin-reorientation transition from an ease-axis state to an easy-plane occurs near 8 K. Anomalies of the magnetization curves are observed in a spin-flop transition induced by the magnetic field B‖c. The calculations were performed using a molecular-field approximation and a crystal-field model for the rare-earth subsystem. Extensive experimental data on the magnetic properties of Nd0.9Dy0.1Fe3(BO3)4 have been interpreted and good agreement between theory and experiment has been achieved using the obtained theoretical dependences. 相似文献
203.
We investigate the Josephson effect for a setup with two lattice quantum wires featuring Majorana zero energy boundary modes at the tunnel junction. In the weak-coupling regime, the exact solution reproduces the perturbative result for the energy containing a contribution ~ ± cos(?/2) relative to the tunneling of paired Majorana fermions. As the tunnel amplitude g grows relative to the hopping amplitude w, the gap between the energy levels gradually diminishes until it closes completely at the critical value gc [Formula: see text]. At this point the Josephson energies have the principal values [Formula: see text], where m =- 1,0,1 and σ =± 1, a result not following from perturbation theory. It represents a transparent regime where three Bogoliubov states merge, leading to additional degeneracies of the topologically nontrivial ground state with an odd number of Majorana fermions at the end of each wire. We also obtain the exact tunnel currents for a fixed parity of the eigenstates. The Josephson current shows the characteristic 4π periodicity expected for a topological Josephson effect. We discuss the additional features of the current associated with a closure of the energy gap between the energy levels. 相似文献
204.
Elena Eremina Yuri Eremin Natalia Grishina Thomas Wriedt 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(14-16):1518-1525
The effect of enhanced optical transmission through subwavelength holes and their arrays is used for multiple practical applications especially in optical antennas and local biosensors design. This effect is usually considered under excitation of plane wave propagating at the normal direction to the screen surface. In this work the effect of extreme transmission through the hole in the evanescent wave's area is in focus. The discrete sources method has been applied to analyse the spectral characteristics of light scattered by a cylindrical nanohole in a noble-metal film on a prism surface. The influence of the wavelength, incident angle, film materials and hole's filling on the scattering characteristics has been investigated. A close correlation between the effect of extreme transmission and the surface plasmon resonances has been detected. 相似文献
205.
E. V. Eremin N. V. Volkov K. A. Sablina O. A. Bayukov M. S. Molokeev V. Yu. Komarov 《Journal of Experimental and Theoretical Physics》2017,124(5):792-804
The indirect-coupling model is used to analyze the exchange magnetic structure of Pb3Mn7O15 in the hexagonal setting. The ratios of manganese ions Mn4+/Mn3+ in each nonequivalent position are determined. Pb3(Mn0.95Ge0.05)7O15 and Pb3(Mn0.95Ga0.05)7O15 single crystals are grown by the solution–melt method in order to test the validity of the proposed model. The structural and magnetic properties of the single crystals are studied. The magnetic properties of the grown single crystals are compared with those of nominally pure Pb3Mn7O15. 相似文献
206.
N.?N.?Anshits O.?A.?Bayukov E.?V.?Eremin L.?A.?Solov’ev E.?V.?Rabchevski? A.?G.?Anshits 《Physics of the Solid State》2010,52(6):1188-1192
Mössbauer, magnetic, and X-ray studies of magnetic microspheres separated from energy ashes have been performed. The major component of the composition of the microspheres is an imperfect magnetite with cation vacancies in which iron is located in trivalent and mixed-valence positions characteristic of stoichiometric magnetite. Moreover, the Fe3+ and Fe2.5+ positions with a cation vacancy among the nearest neighbors and the positions with a partial localization of 3d electrons have been identified. 相似文献
207.
Panina N. S. Nikiforov A. A. Blinou D. O. Dubrov E. N. Ponyaev A. I. Eremin A. V. Belyaev A. N. 《Russian Journal of General Chemistry》2019,89(11):2264-2272
Using the DFT method PBE0/6-31G(d, p) and taking into account the solvent, the formation of bi- and pentahedral Ni(II) complexes with carboxylate and N-containing ligands in the gas phase was studied, and ΔG° of their formation from simple compounds was estimated. The functional role of bridging groups and hydrogen bonds in the formation of polynuclear structures was revealed. A model of self-organization of penta-nuclear coordination compounds [NiII5(O2CR)8L2n(μ-OH)2]0 from binuclear complex [NiII2(O2CR)4Ln(μ-H2O)]0 was proposed, into the structure of which mononuclear NiII cations are embedding and promote proton transfer from bridging aqua ligands.
相似文献208.
The paper briefly reviews the fundamental (general) evolution properties of nonlinear dynamic systems. The stress-strain state evolution in a rock mass with mine openings has been numerically modeled, including the catastrophic stage of roof failure. The results of modeling the catastrophic failure of rock mass elements are analyzed in the framework of the theory of nonlinear dynamic systems. Solutions of solid mechanics equations are shown to exhibit all characteristic features of nonlinear dynamic system evolution, such as dynamic chaos, self-organized criticality, and catastrophic superfast stress-strain state evolution at the final stage of failure. The calculated seismic events comply with the Gutenberg-Richter law. The cut-off effect has been obtained in numerical computation (downward bending of the recurrence curve in the region of large-scale failure events). Prior to catastrophic failure, change of the probability density functions of stress fluctuations, related to the average trend, occurs, the slope of the recurrence curve of calculated seismic events becomes more gentle, seismic quiescence regions form in the central zones of the roof, and more active deformation begins at the periphery of the opening. These factors point to the increasing probability of a catastrophic event and can be considered as catastrophic failure precursors. 相似文献
209.
A. Yu. Panarin A. V. Abakshonok A. N. Eremin S. N. Terekhov 《Optics and Spectroscopy》2017,122(6):896-900
Absorption and resonant light-scattering spectra of nanoparticles (NPs) of silver, and their complexes with water-soluble Cu(II)-5,10,15,20-tetrakis(4-N-methylpyridinium)-porphyrin (CuTMpyP4) and Fe(II)-5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (FeTSPP) have been compared. It is shown that in the presence of cationic CuTMpyP4, the band of surface plasmon resonance in the absorption and resonant scattering spectra of silver NPs is shifted to the long-wavelength region that is associated with the agglomeration of the particles caused by the Coulomb attraction between the silver particles and the porphyrin molecules. Addition of anionic FeTSPP to the silver NP solution does not lead to any spectral changes. The observed effect of silver-NP association induced by the cationic porphyrin can be used to develop an optical method for the detection of nanoparticles in solutions. 相似文献
210.
M. V. Eremin 《JETP Letters》2017,105(11):696-699
A mechanism underlying the magnetoelectric effect is discussed. This mechanism is related to the combined action of an odd crystal field, spin?orbit coupling, and the interaction of the orbital angular momentum with an applied magnetic field. The effective operator describing the spin states of Fe2+ ions is obtained. Such operator allows one to interpret the terahertz spectroscopy data and to calculate both the electric field effect on the magnetization and the magnetic field effect on the electric polarization of the sample. It is demonstrated that the magnetoelectric effect is enhanced with a decrease in the energy corresponding to the tetragonal distortion of ligand tetrahedra. 相似文献