熔锥光纤定向耦合理论

提出了一种分析熔锥光纤定向耦合器及其衍生器件的新数理模型。通过把基模场的高斯理论发展到双包层光纤,并采用正态分布函数来描述耦合区的几何形态,较为完善清晰地反映了模场及边界的渐变特性。导出了本地标量场耦合系数的简洁解析式及其矢量修正式。具体器件的理论计算与实验相符较好。     

分层介质中有垂直金属壁时电磁波的散射

过去在分析具有金属带的分层介质波导中波的传播问题时,常假设金属带平行于介质分界面,但在封闭式介质波导的侧壁或内部也常出现金属壁垂直于分界面的情况,因而对它的分析是研究介质波导的一个基本问题.本文以文献[1]为基础,证明在分层介质波导的垂直金属壁上不可能有模式间的耦合,并得出了这种情况下各模的横向传播常数表示式.文中还以H波导为例,说明这些结果的应用.     

翼片加载螺旋线慢波系统的特性分析

通过切比雪夫多项式展开螺旋带上的面电流,用真空层模拟螺旋带的厚度、均匀分层介质等效介质夹持杆、用无限多个无限薄的翼片等效实际翼片,得到了色散方程、平均耦合阻抗和衰减常数的表达式。与实验数据相比,结果接近实验值,该文提出的方法对实际螺旋线慢波系统的设计具有重要的指导意义。     

稀土氨基酸在混合溶剂中的配位常数测定及热力学常数计算

用ｐＨ法测定了镧和天门冬氨酸在水—二甲基亚砜、钕和甘氨酸在水—二氧六环混合溶剂中的配位常数．测定精度为±０．０１ｐＨ单位．通过加入一定量硝酸钾溶液维持溶液的离子强度（０．１０ｍｏｌ／Ｌ）．测定时采用氮气氛保护并保持温度变化不超过±０．２Ｋ．利用配位常数计算了这些配合物在混合溶液中的△Ｇ°、△Ｈ°和△Ｓ°．     

On maxima of chi-processes over threshold dependent grids

In this paper, with motivation from Piterbarg VI [Discrete and continuous time extremes of Gaussian processes. Extremes. 2004;7(2):161–177] and the considerable interest in stationary chi-processes, we derive asymptotic joint distributions of maxima of stationary strongly dependent chi-processes on a continuous time and a uniform grid on the real axis. Our findings extend those for Gaussian cases and give three involved dependence structures via the strongly dependence condition and the sparse, Pickands and dense grids.     

教学机智：把“课堂意外”转化成“愉悦与收获”——以小学数学教学实践为例

教学机智是教师进行有效教学的必备素质,是充满教育智慧的行动。教师成为学生的"共同遭遇者"是教学机智在教学现场适时产生的心理基础;做学生的"智慧启迪者"是教学机智生成发展的行动方略;做教学的"持续反思者"是教学机智提升境界的必由之路。     

Faster maximum likelihood estimation of very large spatial autoregressive models: an extension of the Smirnov–Anselin result

Maximization of an auto-Gaussian log-likelihood function when spatial autocorrelation is present requires numerical evaluation of an n?×?n matrix determinant. Griffith and Sone proposed a solution to this problem. This article simplifies and then evaluates an alternative approximation that can also be used with massively large georeferenced data sets based upon a regular square tessellation; this makes it particularly relevant to remotely sensed image analysis. Estimation results reported for five data sets found in the literature confirm the utility of this newer approximation.     

A convex quadratic semi-definite programming approach to the partial additive constant problem in multidimensional scaling

Bénasséni [Partial additive constant, J. Statist. Comput. Simul. 49 (1994), pp. 179–193] studied the partial additive constant problem in multidimensional scaling. This problem is quite challenging to solve, and Bénasséni proposed a numerical procedure for two special cases: the cross-set partial perturbation and the within-set partial perturbation. This paper casts the problem as a modern quadratic semi-definite programming (QSDP) problem, which is not only capable of dealing with general cases, but also enjoys a number of good properties. One of the good properties is that the proposed approach can find the minimal constant under very weak conditions. Another is that there exists a ready-to-use numerical package such as the QSDP solver in Toh [An inexact path-following algorithm for convex quadratic SDP, Math. Program. 112 (2008), pp. 221–254], allowing a great deal of flexibility in choosing the index set to which the partial constant should be added. Our numerical results show a significant improvement over that reported in Bénasséni (1994).     

Constant hazard against a change-point alternative: a bayesian approach with censored data

A Bayesian approach to the problem of a constant hazard with a single change-point is developed using noninformative reference priors. We also present a generalization for the comparison for two treatments.     

非线性电感电路的过渡特性

文章对一个非线性动力学电路进行了研究，讨论了非线性RL电路物一些过渡特性。