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771.
772.
Andrzej Wi?nicki 《Journal of Mathematical Analysis and Applications》2002,267(1):158-172
We use a newly introduced concept of neocompactness to study problems from metric fixed point theory. In particular, we give a sufficient condition for a superreflexive Banach space X to have the fixed point property and obtain shorter proofs of some well-known results in that theory. 相似文献
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774.
We consider systems described by boundary-value problems for elliptic second-order partial differential equations with discontinuous coefficients appearing in the study of steady-state processes of filtration of a liquid in multicomponent media under nonhomogeneous conditions of a nonideal contact. Minimax estimates for functionals of solutions of these equations are found by using observations of states of the system. We assume that the right hand sides of equations, boundary conditions, and junction conditions on borders of media as well as errors in measurements are not known precisely, but we know only the sets to which they belong. We prove that the finding of minimax estimates can be reduced to the solving of some systems of integro-differential equations. 相似文献
775.
V. S. Averbakh B. N. Bogolyubov Yu. A. Dubovoi Yu. M. Zaslavskii A. V. Lebedev A. P. Maryshev V. E. Nazarov K. E. Pigalov V. I. Talanov 《Acoustical Physics》2002,48(2):121-127
To excite seismic waves with a high coherence, powerful hydroacoustic radiators placed in a natural reservoir were used. Theoretical estimates and the test data demonstrate a high efficiency of the proposed method of seismic wave excitation. The calculations are in good agreement with the results of measurements. The results of phasing the radiation with the use of two monopole sources separated by a quarter-wave distance are presented. It is shown that the use of the proposed scheme of excitation makes it possible to control the radiation pattern while obtaining a high coherence of seismic waves. 相似文献
776.
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779.
Patterned uniformly (100)-orientated silicon nanocrystallite (SiNC) films were fabricated based on hydrogen ion implantation technique and typical electrochemical anodic etching method. The surface morphology and microstructure characteristics of the films were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and atomic force microscopy. The efficient field emission with low turn-on field of about 3.2 V/μm at current density of 0.1 μA/cm2 was obtained. The emission current density from the SiNC films reached 1 mA/cm2 under a bias field of about 11 V/μm. The experimental results demonstrate that the SiNC films have great potential applications for flat panel displays. 相似文献
780.
Polaron effects on third-harmonic generation (THG) in cylindrical quantum wires with a finite confining potential are investigated. The THG coefficient is obtained by using the compact-density-matrix approach and an iterative method, and the numerical results are presented for GaAs/AlAs cylindrical quantum wires. The results show that the THG coefficient is greatly enhanced and the peak shift to the aspect of high energy when considering the influence of electron-phonon interaction. 相似文献