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951.
We study the concentration of adatoms on GaAs(001) during annealing under MBE conditions. By rapidly cooling the sample from typical growth temperatures and typical As overpressures, the thermal concentration of adatoms can be frozen into small islands on the terraces. The area of the resulting islands is measured with STM far from terrace steps, giving an estimate of the concentration of adatoms during equilibrium. We find that a surprisingly large concentration of adatoms is present for typical growth temperatures, e.g. 0.18 monolayer at 600°C. Possible consequences for current growth models are discussed. 相似文献
952.
The polarization properties of Gaussian Schell-model (GSM) beams and partially polarized Gaussian Schell-model (PGSM) beams passing through a polarization grating (PG) are studied based on the beam coherence-polarization (BCP) matrix formulism, where the finite size of the PG is considered. Detailed numerical calculation results are given and compared with the previous work. 相似文献
953.
954.
In this paper, the problem of partial equiasymptotic stability for nonlinear time-varying differential equations are analyzed. A sufficient condition of partial stability and a set of sufficient conditions of partial equiasymptotic stability are given. Some of these conditions allow the derivative of Lyapunov function to be positive. Finally, several numerical examples are also given to illustrate the main results. 相似文献
955.
J. Límaco H. R. Clark A. J. Feitosa 《Mathematical Methods in the Applied Sciences》2005,28(4):457-478
We investigate a initial‐boundary value problem for the nonlinear beam equation with variable coefficients on the action of a linear internal damping. We show the existence of a unique global weak solution and that the energy associated with this solution has a rate decay estimate. Besides, we prove the existence and uniqueness of non‐local strong solutions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
956.
Kong Hong Jin Lee Jae Yong Shin Yun Sup Byun Jae Oh Park Hee Su Kim Hyogun 《Optical Review》1997,4(2):277-283
Beam recombination characteristics were numerically investigated in array laser amplification using stimulated Brillouin scattering phase conjugation. To clarify the effect of piston errors due to imperfect phase locking, spatial intensity profiles of the beam recombination output were calculated in both the near and the far field on the basis of Rayleigh-Sommerfeld diffraction theory. The analyses indicate that piston errors are seriously detrimental to the quality of a beam recombination output and should be eliminated by a proper phase locking. It is also found that the gap between the beam splitting-combining wedges has a negligible effect.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27-29, Saitama, Japan. 相似文献
957.
1.IntroductionInthepastfe\\'ycarsltllcil1tcnsity-momentsmethodandtheM2factorhavebeenre-vea1edtobeveryuscfulrotlcscribethepropagationlawandthebeamqualityofastaticlightbeam[l~Jj.Rccent1y,1ncji:1sctal.generalizedtheintensitymomentsmethodfortheSCLQ(speetral1y`"el1-centcrcdandlocallyquasi-monochromatic)pulsedlightboms[5j.Itisapparentthatthosercsu]tsubtainedinreferenceL5]areon1yvalidfortheso-calledquasi-monochromaticlightbeamsandarenotvalidforgeneralpolychromaticpulsedlightbeams,esPeciallyaredono… 相似文献
958.
部分相干光学成像系统的光学传递函数和像质评价准则 总被引:4,自引:2,他引:2
根据光学成像理论,建立了部分相干成像光学系统的光学传递函数。该函数与非相干成像光学系统传递函数相同,因而部分相干成像和非相干成像两者的光学系统波面像差公差标准也是相同的。这一点解释了显微镜光学系统的光学设计惯用法则:镜头像差公差标准的选择,并不因为采用成像照明方式的不同而有所差异。 相似文献
959.
960.
Restoration of Decentered Gaussian Beam with the Combination of a Lens and a Gaussian Aperture 总被引:1,自引:0,他引:1
1 Introduction TheGaussianbeamisthefundamentalshapeofthelaserwithaspherical mirrorresonatorandwidelyusedtodescribeasinglemodelaser.Intheparaxialapproximation ,thedistributionofcomplexamplitudeofitremainsunchangedwhenitundergoestheFouriertransformorthe… 相似文献