光束传播法分析硅交叉波导光开关的光学效应

运用光束传播法对硅交叉波导全内反射光开关中的光学效应进行了详细分析。结果表明：１）光学表面衰减波和泄漏波所引发的光遂道效应对开关特性有重要影响；２）反射端功率的相对大小于与反射区界面位置密切相关，其起因是古斯－汉欣位移；３）合理考虑这些因素的影响可以大大降低器件对折射率变化的要求。     

A generalized BPX multigrid framework covering nonnested V-cycle methods

More than a decade ago, Bramble, Pasciak and Xu developed a framework in analyzing the multigrid methods with nonnested spaces or noninherited quadratic forms. It was subsequently known as the BPX multigrid framework, which was widely used in the analysis of multigrid and domain decomposition methods. However, the framework has an apparent limit in the analysis of nonnested V-cycle methods, and it produces a variable V-cycle, or nonuniform convergence rate V-cycle methods, or other nonoptimal results in analysis thus far.

This paper completes a long-time effort in extending the BPX multigrid framework so that it truly covers the nonnested V-cycle. We will apply the extended BPX framework to the analysis of many V-cycle nonnested multigrid methods. Some of them were proven previously only for two-level and W-cycle iterations. Some numerical results are presented to support the theoretical analysis of this paper.

     

Two new coumarin glucosides biosynthesized by transgenic hairy roots of Polygonum multiflorum

The glycosylation of hydroxylcoumarin was investigated by using suspension cultures of hairy roots of Polygonum multiflorum. Two new coumarin glucosides （3 and 4） were biosysthesized by regioselectively glycosylation of corresponding substrates （1 and 2） in the system. The structures of two products were identified as 7-hydroxy-4-methylcoumarin 5-O-β-D-glucopyranoside and 7- hydroxy-3,4-dimethylcoumarin 5-O-β-D-glucopyranoside on the ground of chemical and spectroscopic methods, respectively. 2007 Rong Min Yu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

马尔可夫模型的市场预测方法及其应用

本文简述了马尔可夫模型的基本原理，介绍了利用马氏过程的基本特征．即其平稳性和无后效性．对随机现象进行统计预测的方法。本文选取市场为研究对象，根据产品的市场占有率的随机变化过程，建立起市场占有率的马尔可夫预测模型，并进行了实例分析。在模型的实际应用时，要注意系统状态转移的平稳性和进行系统状态划分的有效性。     

A5与PSL（2，7）的特征及有限CIT—群

本文验证了A5和PSL（2，7）是非阿贝尔单群中含对合数最少的两个群（前者含15个对合，后者含21个对合）。同时，对有限CIT－群G的可解性和有限不可解CIT－群的对合数也做了讨论。     

OPTICAL DIAGNOSTIC AND MODELING SOLUTION GROWTH PROCESS OF SODIUM CHLORATE CRYSTALS

Both a real time optical interferometric experiment and a numerical simulation of two-dimension non-steady state model were employed to study the growth process of aqueous sodium chlorate crystals. The parameters such as solution concentration distribution, crystal dimensions, growth rate and velocity field were obtained by both experiment and numerical simulation. The influence of earth gravity during crystal growth process was analyzed. A reasonable theory model corresponding to the present experiment is advanced. The thickness of concentration boundary layer was investigated especially. The results from the experiment and numerical simulation match well.     

Z箍缩等离子体不稳定性的数值研究

利用二维辐射磁流体程序模拟了钨丝阵Z箍缩等离子体腊肠不稳定性的演化：分析了存在不稳定性与没有不稳定性条件下等离子体内爆的差异；研究了不同初始密度扰动对x射线输出 功率和能量的影响.数值结果表明，在一定初始密度扰动范围内，这种不稳定性对x射线输 出的总能量影响不显著，但对x射线功率随时间变化的曲线有明显的影响.此外，还探讨了Z 箍缩等离子体数值模拟中低密度区的数值处理对数值结果的影响. 关键词： Z箍缩 腊肠不稳定性 数值模拟     

Study on the behavior of hyper-rayleigh scattering for silver nanoparticles with aggregation effects

The absorption spectra as well as the Hyper-Rayleigh scattering (HRS) signals of a highly monodisperse 10.5-nm diameter silver colloids with the addition of KNO(3) and pyridine have been measured. Strongly enhanced HRS signals are observed by 15x and 6x, respectively. Through size distribution and TEM measurements, the morphology of aggregated silver nanoparticles has been observed as a chainlike aggregation. The dramatically enhanced second-order nonlinearity was explained by the enhanced electromagnetic (EM) field near the surface of the silver nanoparticles as they approached. The different enhancement between these two kinds of aggregates was considered with the diversity of separated distance between silver nanoparticles. The experimental results reveal that there is an optimum size for the aggregates to yield the maximum HRS response.