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21.
Using superposition of solutions and Fourier series we study the stressed state in a transversally isotropic layer with a
cavity. We describe the results of numerical studies as functions of the elastic properties of the material, the geometric
characteristics of the body, and the nature of the load variation. Four figures.
Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 25, 1995 pp. 8–15. 相似文献
22.
I. V. Ryzhov N. A. Vasil’ev I. S. Kosova M. D. Shtager V. A. Malyshev 《Journal of Experimental and Theoretical Physics》2017,124(5):683-700
Cooperative radiation emitted by an ensemble of three-level optical systems with a doublet in the ground state (Λ scheme), which is placed into a cyclic cavity, is studied theoretically. In contrast to the two-level model of emitters, this process with such a configuration of operating transitions may occur without population inversion in the whole, if the doublet is prepared at the initial instant in a superposition (coherent) state. In the ideal case of a Hamilton system, in which the cavity losses and relaxation in the radiator ensemble are disregarded, the conservation laws are derived, which allow a substantial reduction of the dimension of the phase space of the model (?11 → ?5) and the application of methods of dynamics of nonlinear systems for analyzing the three-level superradiance under these conditions. The possibility of different (both quasiperiodic and chaotic) scenarios of the three-level superradiance is demonstrated on the basis of Poincaré’s mappings. Global bifurcation of the system upon a transition from the conventional superradiance regime to inversionless one is revealed. The effects of cavity losses, as well as homogeneous and inhomogeneous broadening in the system of radiators on the regularities found are also discussed. 相似文献
23.
Solid state mechanical activation method was applied for surface modification of LiMn2O4 by Li-M-O (M = Co, Co+Ni) and for preparation of composite mixed LiMn2O4/LiCoO2 cathode materials. Pristine LiMn2O4 was ground with correspondent precursors (for coating) or with LiCoO2 (for composites) in high-energy planetary mills and then heat treated at different temperatures. As prepared materials were studied by XRD, 7Li MAS NMR spectroscopy, XPS, SEM and electrochemical cycling. It has been shown that both ‘core-shell’ and composite materials prepared by mechanochemical process are characterized by superior electrochemical performance due to smaller particles and chemical modification of LiMn2O4. 相似文献
24.
V.?A.?SevryuginEmail author N.?M.?Azancheev G.?N.?Kosova 《Applied magnetic resonance》2018,49(4):357-367
The concentration dependences of self-diffusion coefficients of water and ethanol molecules in water–ethanol solutions are obtained by the method of nuclear magnetic resonance spectroscopy with the pulse magnetic field gradient. On the basis of the ideas of hydration of ethanol molecules, the obtained dependences are interpreted and assumptions are made about the structural organization of water–ethanol solutions in the region of diluted and concentrated solutions. 相似文献