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161.
Raúl Ferreira Pablo Groisman Julio D. Rossi 《Numerical Methods for Partial Differential Equations》2004,20(4):552-575
We study numerical approximations of positive solutions of the porous medium equation with a nonlinear source, where m > 1, p > 0 and L > 0 are parameters. We describe in terms of p, m, and L when solutions of a semidiscretization in space exist globally in time and when they blow up in a finite time. We also find the blow‐up rates and the blow‐up sets, proving that there is no regional blow‐up for the numerical scheme. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004 相似文献
162.
A simple HPLC method was developed and validated for quantification of linezolid in Brain Heart Infusion (BHI) broth. Eperezolid was employed as internal standard and the sample pre-treatment procedure was simple. Calibration standards ranged from 0.05 to 16 mg/L. Accuracy was within 7.8% and reproducibility (RSD) was less than 8.3%. Recovery was approximately 100% at all concentrations examined. Linezolid was stable in the autosampler insert for at least 24 h at ambient temperature and in BHI for 72 h at 37 degrees C. This assay is rapid and ideal for analysis of a large number of samples. 相似文献
163.
164.
ZhuJianxin 《高校应用数学学报(英文版)》2000,15(4):443-452
In this paper, a local orthogonal transformation is created to transform the Helmholtz waveguide with curved interface to the one with a flat interface within the two-layer medium, and the Helmholtz equation uxx uzz k^2(x,z)u=0 is transformed to Vxx αVzz βVz γV=0. Numerical results demonstrate that the transformation is more feasible. This transformation is particularly useful for the research on wave propagation in acoustic waveguide. 相似文献
165.
166.
环形光束的非线性传输及聚焦特性研究 总被引:1,自引:0,他引:1
针对用于产生光镊的环形光束,利用分步傅里叶-贝塞尔变换算法,对二维环形超高斯光束的非线性传输及聚焦过程进行了数值模拟,给出了环形光束聚焦场附近的光强分布,并分析了非线性调制对聚焦性质(包括焦面中心光强、焦面光强的横向分布、轴上光强和光束质量)的影响.研究表明,从聚焦角度来看,非线性调制中的位相调制比振幅调制对环形光束聚焦性质的影响程度要大;从非线性传输角度来看,随着非线性介质长度的增加,位相调制和振幅调制对环形光束聚焦性质各有不同程度的加剧,其中非线性作用对振幅调制的影响要比位相调制明显. 相似文献
167.
168.
Electrooptical Kerr effect has been studied in binary solutions of a dipolar liquid (-picoline, β-picoline) in a non-dipolar solvent (benzene, p-xylene) and 1,4-dioxane in the full range of concentrations of the dipolar component (0 ≤ f2 ≤ 1). The experimental Kerr constant Ks of the solutions, refraction index ns, density ρs and the dielectric constant εs have been measured and used for the calculation of the molar Kerr constants KSM within the Onsager local field model. Analysis of changes in the molar Kerr constants as a function of the solute concentration by fits of theoretical functions to the experimental ones has permitted a determination of the parameters characterizing intermolecular interactions in binary solutions. 相似文献
169.
This study presents the electromagnetic wave propagation through the frequency-dispersive and lossy double-negative slab embedded
between two different semi-infinite media. The double-negative slab is realized by using two models, the Lorentz and Drude
medium models. The properties and the required equations for the frequency-dispersive and lossy double-negative slab, the
Lorentz medium and Drude medium are given in detail. After the construction of the problem, the reflection and transmission
coefficients are derived for both TE and TM waves. Then, the reflected, transmitted and loss powers are determined using these
coefficients. Finally, in the numerical results, the mentioned powers for TE and TM waves are computed and illustrated as
a function of the incidence angle, the frequency and the slab thickness when the damping frequency changes. 相似文献
170.
Hongwei Yang Wanchun Tang Xiangkun Kong 《International Journal of Infrared and Millimeter Waves》2007,28(7):547-556
In this paper, shift operator finite-difference time-domain (SO-FDTD) method is applied for the calculation of the dispersive
medium. The high efficiency and accuracy of this method is verified by calculating the reflection of the plane electromagnetic
wave impinging on a non-magnetized plasma slab with different electron density distributions. The results show that the average
electron density only determines overall trends of the reflection, and different distributions affect the oscillating process
of the reflection. If the average electron density maintains the same, the distribution of electron density with homogenous
or inhomogeneous alternation will sharply take effects on the reflection. And magnitude of alternation of electron density
affects the incident frequency directly when the reflection tends to uniform. 相似文献