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排序方式: 共有722条查询结果,搜索用时 10 毫秒
1.
Yurii P. Kalmykov 《Liquid crystals》1991,10(4):519-537
The relationship between the complex dielectric permittivity tensor of a polar nematic liquid crystal and the autocorrelation matrix for the permanent dipole moment of a molecule is obtained. The theory is applicable to the whole frequency range which characterizes orientational relaxation in liquid crystals (up to ∼ 5 THz). The models of rotational diffusion and extended rotational diffusion in a mean field nematic potential are used to evaluate the dielectric absorption and dispersion in nematics. 相似文献
2.
Boris A. Trofimov Ol’ga V. Petrova Lyubov’ N. Sobenina Igor’ A. Ushakov Al’bina I. Mikhaleva Yurii Yu. Rusakov Leonid B. Krivdin 《Tetrahedron letters》2006,47(22):3645-3648
Functionalized pyrrolic enols, 2-(2,2-dicyano-1-hydroxyethenyl)-1-methylpyrroles, synthesized from 2-ethenylpyrroles by a nucleophilic SEt-OH exchange, upon heating (75-142 °C) are readily rearranged to their 3-isomers in near to quantitative yield. The inter or intramolecular auto-protonation of a pyrrole ring by the acidic enol hydroxyl to form a mesomeric pyrrolium cation or zwitterion is suggested to be a key step in the rearrangement. 相似文献
3.
4.
Oleg L. Berman Roman Ya. Kezerashvili Yurii E. Lozovik David W. Snoke R. Balili B. Nelsen L. Pfeiffer K. West 《Superlattices and Microstructures》2011
The theoretical and experimental status of the Bose–Einstein Condensation (BEC) of trapped quantum well (QW) polaritons in a microcavity is presented. The results of recent experiments that have shown the possibility to create an in-plane harmonic potential trap for a two-dimensional (2D) exciton polaritons in a cavity are discussed. We report the theory of BEC and of the trapped QW exciton polaritons in a microcavity. In addition, we study the BEC of trapped magnetoexciton polaritons in a graphene layer (GL) embedded in an optical microcavity in high magnetic field. In both cases the polaritons are considered to be in a harmonic potential trap. We compare the theoretical results with the existing experiments and discuss the experimental observation of predicted phenomena. 相似文献
5.
6.
Sergey P. Gladchenko Yurii Z. Kovdrya Viktor A. Nikolaenko 《Journal of Molecular Liquids》2005,120(1-3):175-179
Conductivity of electrons in a quasi-one-dimensional (Q1D) system over liquid helium in narrow channels with the parabolic profile of the potential well has been investigated at temperature T, from 0.4 to 1.8 K, for different driving electric fields and radius of channel curvature. The interval of linear electron densities varied from 2.18×103 up to 1.7×106 cm−1.
The inverse mobility (1/μeff) in the electron-ripplon scattering region at the high linear densities of charges in the channel increases with temperature decreasing. This anomalous behavior of the electron transport in the low-temperature region has been explained by either the electron ordering or the polaronic effects in confined conducting channels. The nonlinear behavior of the electron velocity as a function of a driving electric field is supposed to be due to Breg–Cherenkov radiation of the ripplons. The radiation occurred if the velocity of electrons in the channel approaches to the critical value. 相似文献
7.
The original theory of a proximity effect is proposed for the bi- and tri-layered system ferromagnetic metal/superconductor (F/S) in dirty limit. The F1/S/F2 trilayer is examined more closely. The distinctions in materials, in thicknesses of F layers (df1 and df2), in parameters interfaces, and in local environments of layers are considered among the causes of incommensurability of trilayer. The peculiar Tc(df1, df2) interference pattern is predicted for the F1/S/F2 systems. The reentrant superconductivity and possibility of the better observability of the spin-valve regime are discussed. 相似文献
8.
Victor A. Soltamov Ivan V. Ilyin Alexandra A. Soltamova Daniel O. Tolmachev Nikolai G. Romanov Alexandr S. Gurin Vladimir A. Khramtsov Eugene N. Mokhov Yurii N. Makarov Georgy V. Mamin Sergei B. Orlinskii Pavel G. Baranov 《Applied magnetic resonance》2013,44(10):1139-1165
The results of studies of shallow donors and deep-level color centers in bulk AlN crystals are presented. Two shallow donors (presumably oxygen located on the nitrogen site and carbon located on the aluminum site) are suggested to exhibit the DX-relaxation. Third shallow donor (presumably silicon on the Al site) shows the shallow donor behavior up to the room temperature and can be observed without light excitation at temperatures above 200 K. The values of the Bohr radius of the shallow donors are estimated. The structure of deep-level color centers (neutral nitrogen vacancy V N) in bulk AlN crystals is determined and analyzed by electron paramagnetic resonance, electron-nuclear double resonance, optical absorption and thermoluminescence induced by X-ray irradiation. Spin-dependent recombination processes in AlN crystals are studied by means of optically detected magnetic resonance. 相似文献
9.
Yurii E. Lozovik Igor A. Nechepurenko Alexander V. Dorofeenko Eugeny S. Andrianov Alexander A. Pukhov 《Physics letters. A》2014
We propose a method for high-sensitivity subwavelength spectromicroscopy based on the usage of a spaser (plasmonic nanolaser) in the form of a scanning probe microscope tip. The high spatial resolution is defined by plasmon localization at the tip, as is the case for apertureless scanning near-field optical microscopy. In contrast to the latter method, we suggest using radiationless plasmon pumping with quantum dots instead of irradiation with an external laser beam. Due to absorption at the transition frequencies of neighboring nano-objects (molecules or clusters), dips appear in the plasmon generation spectrum. The highest sensitivity is achieved near the generation threshold. 相似文献
10.
Alexander A. Redkin Elena V. Nikolaeva Alexander E. Dedyukhin Yurii P. Zaikov 《Ionics》2012,18(3):255-265
The interrelationship between electrical conductivity, molar volume and enthalpy of mixing was studied for molten chlorides
and their mixtures. The dependence of electrical conductivity and activation energy on the molar volume is different for various
groups of salts. The dependence of specific conductivity on molar volume obtained for molten alkali chlorides was found to
be similar to other chloride salts. The specific conductivity of binary mixtures that lack strong chemical interactions between
the components can also be described by the proposed empirical equation. The enthalpy of mixing should be taken into consideration
for these chemical interactions. 相似文献