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991.
992.
We prove new theorems on the justification of the averaging method for multifrequency oscillation systems with pulse influence at fixed times. 相似文献
993.
Lasing and discharge in mixtures of SF6 with hydrogen and hydrocarbons are investigated. If the chemical reaction is initiated by a self-sustained discharge (a generator
with both an inductive and capacitive energy storage can be used), the maximum lasing efficiency is attained at high values
of the ratio E/p (where E is the electric field intensity and p is the pressure in the mixture) if shaped electrodes and preionization of the discharge gap are employed. For the first time,
the lasing efficiency obtained in a nonchain HF laser is as high as 10% of the energy deposit and 4.5% of the stored energy
for a specific radiation energy of ≈140 J/(l atm). At high efficiencies, the emission spectrum of the nonchain HF laser significantly
broadens and cascade lasing at P(3-2) → P(2-1) → P(1-0) vibrational transitions for several rotational lines is realized. 相似文献
994.
R. M. Sardarly O. A. Samedov I. Sh. Sadykhov V. A. Aliev 《Physics of the Solid State》2003,45(6):1118-1121
The relaxor properties of Fe-doped TlInS2 crystals are investigated. It is shown that Fe-doped TlInS2 compounds exhibit all features inherent in relaxor ferroelectric materials. The temperature range of existence of the microdomain (relaxor) state and the temperature of the transition from this state to a macro-domain state are determined. 相似文献
995.
V. L. Tsymbalenko 《JETP Letters》2003,78(8):493-496
The kinetics of formation of an anomalous phase from a solution with a small 3He impurity was studied in the temperature range 0.2–0.7 K up to a supersaturation of ~30 mbar. The phase diagram was determined for normal and anomalous growths. It is found that, in the presence of impurities, the formation of a fast-growing state is retarded. This experimental fact indicates that the dissipative processes in fluids have an appreciable effect on the phase formation kinetics. The retardation is, possibly, caused by the direct interaction of an impurity with the crystal surface. 相似文献
996.
G. M. Maksimova A. L. Chuvilin E. M. Moroz V. A. Likholobov K. I. Matveev 《Kinetics and Catalysis》2004,45(6):870-878
Conditions for the preparation of stable aqueous monometallic and bimetallic colloidal solutions (sols) of noble metals (Ru, Rh, Pd, Pt, Ir, Ag, and Au) in the presence of polyoxometalates containing W, Mo, V, and Nb were found. The stability of sols against coagulation at room temperature was studied. The metal/C samples prepared by metal adsorption from sols were studied by powder X-ray diffraction analysis and transmission electron microscopy. The following factors of importance for the preparation of a stable sol are discussed: (1) the formation of a sol of a metal polyhydroxo complex stabilized by a polyoxometalate (preliminary stage) and (2) the formation of polyoxometalate-metal clusters in the course of reduction of polyhydroxo complexes.Translated from Kinetika i Kataliz, Vol. 45, No. 6, 2004, pp. 921–929.Original Russian Text Copyright © 2004 by Maksimova, Chuvilin, Moroz, Likholobov, Matveev. 相似文献
997.
基于新型长周期光纤光栅的掺铒光纤放大器 总被引:10,自引:8,他引:2
报道了基于高频CO2激光脉冲写入的新型长周期光纤光栅的低噪音掺铒光纤放大器,这种新型长周期光纤光栅是用大约几千Hz的高频CO2激光脉冲对光纤玻璃热冲击作用而形成的.在铒纤中插入一个长周期光纤光栅,会明显减少掺铒光纤放大器的放大自发辐射(ASE)噪音.报道了两种低噪音掺铒光纤放大器,作为前置放大器和线路放大器,它们的ASE噪音指数分别从4.0 dB减少到3.5 dB和从4.8 dB减少到4.3 dB,并且在作为线放时,其小信号增益从30 dB提高到37 dB,降噪及提高增益效应十分显著. 相似文献
998.
Summary. We consider the spline collocation method for a class of parabolic pseudodifferential operators. We show optimal order convergence
results in a large scale of anisotropic Sobolev spaces. The results cover the classical boundary integral equations for the
heat equation in the general case where the spatial domain has a smooth boundary in the plane. Our proof is based on a localization
technique for which we use our recent results proved for parabolic pseudodifferential operators. For the localization we need
also some special spline approximation results in anisotropic Sobolev spaces.
Received May 17, 2001 / Revised version received February 19, 2002 / Published online April 17, 2002 相似文献
999.
E. A. Bogdanov A. A. Kudryavtsev L. D. Tsendin R. R. Arslanbekov V. I. Kolobov V. V. Kudryavtsev 《Technical Physics》2003,48(9):1151-1158
Comprehensive self-consistent simulations of the positive column plasma of a dc oxygen discharge are performed with the help
of commercial CFDRC software (), which enables one to carry out computations in an arbitrary 3D geometry using fluid equations for heavy components and
a kinetic equation for electrons. The main scaling laws for the spatial distributions of charged particles are determined.
These scaling laws are found to be quite different in the parameter ranges that are dominated by different physical processes.
At low pressures, both the electrons and negative ions in the inner discharge region obey a Boltzmann distribution; as a result,
a flat profile of the electron density and a parabolic profile of the ion density are established there. In the ion balance,
transport processes prevail, so that ion heating in an electric field dramatically affects the spatial distribution of the
charged particles. At elevated pressures, the volume processes prevail in the balance of negative ions and the profiles of
the charged particle densities in the inner region turn out to be similar to each other. 相似文献
1000.
A solution to the problem of nonlinear surface vibration of a charged ideal liquid drop is found in a third-order approximation in initial multimode deformation of the equilibrium spherical shape by the method of many scales. It is shown that the spectrum of modes that are responsible for the shape of the drop at an arbitrary time instant depends considerably on the spectrum of modes governing the initial deformation of the drop. The latter spectrum also has an effect on nonlinear corrections to the vibration frequencies and, consequently, on a nonlinear correction to the critical Rayleigh parameter, which specifies the stability of the drop against self-charge. 相似文献