晶体学与准晶体学点群的母子群关系

依据群论，得出了准晶体学点群的直积或半直积推导算式；依据结晶学理论，绘出了五角、八角、十角和十二角晶系各点群的极赤投影图.据此推导出了每一个准晶体学点群的全部最大子群，从而推导并绘制出了三维晶体学和准晶体学点群之间的母子群关系(60个点群的“家谱”).该“家谱”以最大子群链的图解形式直观地给出了每个点群的最小母群和最大子群. 关键词： 准晶体 晶体 点群 最大子群 最小母群 群链     

高能e+e－湮没强子多重数的质量关系

利用一个描述强子质量谱成功的夸克模型确定出得到的强子多重数普适质量关系〈n〉=aexp(–bm)中的参数b,发现对于介子、重子是一个普适的常数.利用这个质量公式给出计算各种粒子多重数的表达式,进而以高能e⁺e^－湮没为例计算出各种粒子多重数与实验以及其他模型做了比较,表明这个没有任何假定的质量关系同样能够解释实验.     

Paul阱中共面两离子系统的能量本征态

通过对Paul阱中共面两离子体系的研究，考虑共面两离子在Paul阱中库仑关联，得到了两离子系统Schrdinger方程的精确解；椐方程的精确解，分析了质心能级简并情况，计算了两离子的平衡距离和低能级的几个态函数，设计程序作出了质心径向概率分布图. 关键词： Paul阱 两离子 共面 量子逻辑操作     

鲁棒稳定性分析的值映射与参数化方法

本文运用值映射与参数化的方法研究了鲁棒D稳定性问题。文中给出了主要结果——参数空间鲁棒分析的边界定理,作为该结果的应用,一些现代鲁棒分析的知名结果,例如多项式族的稜边定理,Kharitonov定理和菱形定理都被简洁地证明出来;给出了一种判定双参数多项式族D稳定的新方法。用该方法可以方便地确定H稳定多项式按一定摄动模式(区间方式和菱形方形)的最大摄动界。     

无催化纳米氧化锌的制备及其光学性质研究

本文采用无催化剂直接蒸发高纯Zn粉,在800℃氧气氛条件下,在Si(111)衬底上生长得到以四角状为主的纳米ZnO(T-ZnO)。T-ZnO纳米线每个角约互成110°,长度约为1.5μm,直径100nm左右;Raman分析表明E2(H)普遍存在于各形态的ZnO;光致发光光谱表明,T-ZnO纳米线的光致发光除了与材料性质有关,还与杂质缺陷有关,蓝绿光带是ZnO的缺陷产生的。     

Investigation of the reaction order for nucleophilic substitution of dialkyl methylphosphonates by alkoxides

The rate of nucleophilic substitution at the phosphorus centre of dialkyl methylphosphonates by methoxide and ethoxide has been studied to investigate the possible involvement of hexacoordinated phosphorus species in this reaction. For alkoxide concentrations less than ca. 1.5 M the rate increases with the square of alkoxide concentration. However, consideration of the activity of the alkoxides, represented by an appropriate acidity function, reveals that only one equivalent of alkoxide is involved in the rate-determining step. Thus, there is no requirement to invoke the intermediacy of a hexacoordinated species in the reaction pathway. © John Wiley & Sons, Inc.     

Nonlinear Filtering for Diffusions in Random Environments

Suppose that the signal X to be estimated is a diffusion process in a random medium W and the signal is correlated with the observation noise. We study the historical filtering problem concerned with estimating the signal path up until the current time based upon the back observations. Using Dirichlet form theory, we introduce a filtering model for general rough signal X ^W and establish a multiple Wiener integrals representation for the unnormalized pathspace filtering process. Then, we construct a precise nonlinear filtering model for the process X itself and give the corresponding Wiener chaos decomposition.     

Clustering study in Eu(DBM)3Phen-doped polymer optical fibers by optical properties and near-field scanning microscopy

The clusters of Eu3+ ion in Eu(DBM)3Phen-doped polymethyl methacrylate (PMMA) have been studied by three means. The relative fluorescence intensity ratio of the 5D0 → 7F2 to 5D0 → 7F1 transitions with different concentrations of Eu3+ in Eu(DBM)3Phen-doped PMMA and metastable-state (5D0) lifetime dependence on Eu3+ concentration are analyzed. The analysis indicates that there are no clustering effects in Eu3+ ions of Eu(DBM)3Phen-doped PMMA when the Eu3+ doping concentration is up to 1.0 wt.-%. At the same time, the clustering effect has not been observed by the scanning near-field optical microscopy (SNOM) in Eu(DBM)3Phen-doped PMMA with 1.0 wt.-% of Eu3+ ions. The analysis reveals that a high concentration of Eu3+ can be incorporated into polymer optical fiber (POF) without clustering effect.OCIS codes: 180.5810, 300.6280, 250.5460, 160.5690.     

四能级原子系统中量子相干增强的Kerr非线性效应的研究

应用密度矩阵方程计算了四能级原子系统中三阶非线性极化率随信号光和探针光频率失谐的变化关系。结果表明，由于量子干涉对信号光强度的敏感性，使四能级原子介质的交叉Kerr非线性作用大大增强，与三能级系统相比，四能级原子介质的Kerr非线性系数可增强两个数量级。