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991.
The interaction between the rotational degrees of freedom of a diatomic impurity molecule and phonon excitations of a two-dimensional atomic matrix commensurate to the substrate is investigated theoretically. It is shown that the translational-rotational interaction leads to renormalization of the crystal field constants and a change in the form of the operator for the rotational kinetic energy as compared to the corresponding expression for a free rotator. The contribution from the rotational degrees of freedom of impurities to the low-temperature heat capacity of a diluted solution of diatomic molecules in the two-dimensional atomic matrix is calculated. The possibility of experimentally observing the predicted effects is discussed. 相似文献
992.
The results obtained upon the electrochemical deposition of composite coatings containing ultrafine-dispersed diamonds produced by detonation synthesis are generalized. The main advantages of such coatings over the well-known composite electrochemical coatings are revealed. 相似文献
993.
P. K. Kashkarov B. V. Kamenev M. G. Lisachenko O. A. Shalygina V. Yu. Timoshenk M. Schmidt J. Heitmann M. Zacharias 《Physics of the Solid State》2004,46(1):104-108
The photoluminescence spectra and kinetics of both erbium-doped and undoped multilayer structures of quasi-ordered silicon
nanocrystals in a silicon dioxide matrix were studied. It was shown that the optical excitation energy of silicon nanocrystals
2–3 nm in size can be practically completely transferred to Er3+ ions in the oxide surrounding the nanocrystals, with its subsequent radiation at 1.5 μm. Possible reasons for the high excitation
efficiency of the Er3+ ions are discussed, and the conclusion is drawn that the F?rster mechanism is dominant in the energy transfer processes occurring
in these structures.
__________
Translated from Fizika Tverdogo Tela, Vol. 46, No. 1, 2004, pp. 105–109.
Original Russian Text Copyright ? 2004 by Kashkarov, Kamenev, Lisachenko, Shalygina, Timoshenko, Schmidt, Heitmann, Zacharias. 相似文献
994.
995.
The effective dielectric, piezoelectric, and elastic constants of two-phase macroscopically piezoactive 3-0 and 3-3 composites
are calculated. It is assumed that one of the components is a polarized ferroelectric ceramic material and the other is an
inactive material with variable elastic properties. The limiting case when the elastic compliances of the inactive material
tend to infinity (porous ferroelectric ceramics) is considered. The adequacy of this model to production technologies of piezoelectric
composites is discussed. Computational results are compared with experimental data. 相似文献
996.
The effect of uniform pressure on the character of metal-dielectric transitions in compensated weakly- and highly doped semiconductors (WHDCS) is considered. The influence of hybridization of resonance quasilocalized impurity states with band continuum states on the transition is shown. Minimum metallic conductivities in p-CdSnAs2 are determined for Mott and Anderson transitions. Special features of the metal-dielectric transformation in weakly-doped narrow- and high energy-gap semiconductors are discussed for the case of hydrogen-like impurities. Anderson localization in WHDCS is also considered. Phase diagrams are presented. 相似文献
997.
998.
999.
K. V. Gogolinskii Z. Ya. Kosakovskaya A. S. Useinov I. A. Chaban 《Acoustical Physics》2004,50(6):664-669
A technique is developed for measuring the modulus of elasticity of a material with a Nanoscan scanning force microscope on the basis of measuring the dependence of probe vibration frequency on the penetration depth of the needle into the specimen. This technique makes it possible to study materials with elastic moduli from 50 to 1000 GPa. The Young moduli of dense films of carbon nanotubes oriented at angles of 45° and 90° to the quartz substrate are measured. From their ratio, the Young modulus in the direction perpendicular to the tubes and the anisotropy of the elastic moduli are determined. A comparison of these values with the corresponding values obtained for a nanotube film deposited on a silicon substrate is carried out. On the basis of this comparison, a conclusion is made concerning the interaction between single-layer nanotubes and between nanotubes in a mixture of single-layer and multilayer ones. 相似文献
1000.
Propagation of a light pulse through a weakly inhomogeneous optical fiber is analyzed. The non-linear envelope equation describing the evolution of polarized pulses is determined by statistical properties of inhomogeneities in the optical fiber. The isotropic Manakov system of equations is shown to be applicable in the presence of high-frequency small-scale defects in the fiber. In the presence of only large-scale inhomogeneities, the signal dynamics are described by an anisotropic system of equations. 相似文献