Normalization corrections to perturbation theory based on a matrix method

We present the derivation of the normalization constant for the perturbation matrix method recently proposed. The method is tested on the problem of a binary waveguide array for which an exact and an approximate solution are known. In our analysis, we show that to third order the normalized matrix method approximate solution gives results coinciding with the exact known solution.     

A simple perturbative tool to calculate plasmonic photonic bandstructures

We use first order perturbation theory to study the effect of surface plasmon polaritons on the photonic band structure of plasmonic photonic crystals. Our results are based on a simple numerical tool that we have developed to extend the standard frequency domain methods to compute the photonic band structure of plasmonic photonic crystals. For a two-dimensional honeycomb photonic crystal with a lattice constant of 500 nm placed on an aluminium substrate, we show that the band gap for TM modes is enhanced by 13%. Thus a slight variation in the effective dielectric function results in a plasmonic band structure that is not scale-invariant, which is reminiscent of the inherent non-linear properties of the effective dielectric constant.     

介质多层膜的热吸收

根据薄膜光学基本理论,利用一级近似数学方法,给出S,P偏振态平行光在两弱吸收介质边界反射率及透射率的简单表达式,并依此研究了弱吸收介质单层膜及多层膜的热吸收。结果表明,单一膜层的热吸收率,在膜层参数确定的条件下,不仅取决于此膜层材料的消光系数,而且取决于相邻膜层的消光系数。     

求解局部不规则微带贴片的快速有效的方法

本文提出了一种快速分析局部不规则微带贴片的方法.局部不规则贴片可看成是在规则贴片上进行一些修正而得到,规则贴片可以用快速而准确的空腔模型法分析,修正部分中的切角可以利用电路的概念得到,而边缘场可利用精确的全波离散复镜象得到.该方法简单,物理概念清楚,数值结果表明该方法准确而高效.     

Postbuckling of shear deformable laminated plates under biaxial compression and lateral pressure and resting on elastic foundations

Postbuckling analysis is presented for a simply supported, shear deformable laminated plate subjected to biaxial compression combined with uniform lateral pressure and resting on an elastic foundation. The lateral pressure is first converted into an initial deflection and the initial geometrical imperfection of the plate is also taken into account. The formulations are based on the Reddy's higher-order shear deformation plate theory, and including the plate-foundation interaction. The analysis uses a perturbation technique to determine the buckling loads and the postbuckling equilibrium paths. Numerical examples are presented that relate to the performances of perfect and imperfect, antisymmetrically angle-ply and symmetrically cross-ply laminated plates under combined loading and resting on Pasternak-type or softening nonlinear elastic foundations from which results for Winkler elastic foundations are obtained as a limiting case. The effects played by foundation stiffness, transverse shear deformation, plate aspect ratio, total number of plies, fiber orientation, the biaxial load ratio and initial lateral pressure are studied.     

反应堆动态参数的蒙特卡罗计算研究

介绍缓发中子有效份额(βeff)、有效中子代时间(Λeff)和本征值的概念及其蒙特卡罗程序计算方法。采用Prompt Method方法计算得到βeff;微扰法得到Λeff;采用瞬发中子密度衰减直接拟合法和间接求解法得到本征值;将各种反应性状态下的拟合得到临界c本征值,并与实验测量的c值进行比对,结果符合很好;并对动态参数蒙特卡罗程序计算的各种方法进行不确定度分析。     

变形圆微带天线谐振频率的研究

微带天线的窄频带在很大程度上限制了它在许多方面更广泛应用。如何展宽其频带一直为国内外学者所关注。本文用变分法并结合微扰理论分析了一种变形圆贴片宽频带微带天线的谐振频率。理论计算值与实测结果一致性较好,为微带天线谐振特性的综合奠定了一定基础。     

热轧异型钢材截面尺寸在线检测的三维误差分析

介绍了用光截面法在线检测型材截面尺寸时的三维误差分析,应用摄动法建立了三维误差的数学模型,并进行了仿真计算。根据计算结果及其分析,给出了检测系统测量装置的设计参数。     

摄动加权残量法分析薄板几何非线性问题

本文提出了一种摄动加权残量法或称 PWRM。这对我们去解决薄板几何非线性问题提供了一种有效的方法。PWRM 可以克服摄动法用于其他边界形状薄板几何非线性问题所遇到的困难,也可以避免加权残量法须求解非线性代数方程组的缺点,明显地减少了计算工作量。