基于模式理论光栅椭偏参数反演的数值模拟

将一种广泛用于求解系统优化问题的方法——正单纯形法，求解光栅的椭偏方程。首先，利用求解光栅的傅立叶模式理论对TE和TM波的复反射系数进行求解。然后计算出其相应的椭偏参数(△，Ψ)，并在该值的基础上加入不同偏差的随机高斯噪声，将加入噪声后的值(△m，Ψm)作为模拟测量值。最后使用优化算法进行反演。通过对几种常用面形光栅椭偏参数的数值模拟，一方面表明傅立叶模式理论计算光栅的椭偏参数不仅精度高。而且速度快；另一方面表明利用正单纯形法得到的光栅参数值很接近于正演时假设的参数值，从而从理论上证明了利用椭偏法测量光栅各种光学参数的可行性。     

Whispering-gallery-like modes in square resonators

The mode frequencies and field distributions of whispering-gallery (WG)-like modes of square resonators are obtained analytically, which agree very well with the numerical results calculated by the FDTD technique and Pade approximation method. In the analysis, a perfect electric wall for the transverse magnetic mode or perfect magnetic wall for the transverse electric mode is assumed at the diagonals of the square resonators, which not only provides the transverse mode confinement, but also requires the longitudinal mode number to be an even integer. The WG-like modes of square resonators are nondegenerate modes with high-quality factors, which make them suitable for fabricating single-mode low-threshold semiconductor microcavity lasers.     

Fringing in tubular permanent-magnet machines: Part I. Magnetic field distribution, flux linkage, and thrust force

This paper extends an analysis developed for tubular permanent-magnet machines to account for the effect of fringing associated with the finite length of the ferromagnetic armature core. The magnetic field distribution, established by using an analytical technique formulated in the cylindrical coordinate system, provides an accurate means of evaluating the effect of the fringing flux on the thrust force and the back-electromotive force. Finite-element calculations confirm the analytically derived results. In Part II of the paper, the analysis is used to predict the cogging force that results from end effects and to facilitate minimization of the force.     

原油常减压装置节能技术

由于常减压装置消耗能量约占炼油厂总用能的25％～30％，已成为炼油厂中消耗量最大的装置，因此，我国各炼油厂对常减压装置进行以降低能耗为中心的技术改造就显得十分必要。详细介绍了适用于常减压装置节能的新工艺、新设备以及优化操作。工艺方面主要有采用过滤脱盐新技术对原油进行深度脱盐、采用强化蒸馏新工艺提高原油蒸馏拔出率、优化产出、增产柴油；设备方面主要使用规整填料和新型塔板改善分馏塔分馏效率、使用新型燃烧器提高加热炉效率、使用新型换热器提高热回收率、采用变频技术降低装置电耗；优化操作方面主要有利用计算机进行监控与管理和改善操作条件。最后对国内原油常减压装置节能改造提出了一些建议，以供炼油企业在进行原油常减压装置改造时参考。     

基于移动代理的网络拓扑发现研究

提出了一种基于移动代理的分布式网络管理系统模型,阐述了该系统发现网络拓扑的过程,介绍了具体算法思想,给出了数据结构和算法描述,最后进行了仿真,证明了算法的有效性.     

溶胶--凝胶镀膜技术综述(连载5)

第三节　常见氧化物膜目前研究最多的氧化物膜可谓二氧化硅和二氧化钛膜 ,这两种薄膜也是接受呈色离子、制备彩色镀膜常用的基体膜 ,所以 ,有必要将它们单独列出 ,加以讨论。1　二氧化钛膜在所有高折射率材料中 ,由钛的化合物制备的氧化物膜具有特殊的实际意义。因此 ,对二氧化     

Dispersion-relation-preserving FDTD algorithms for large-scale three-dimensional problems

We introduce dispersion-relation-preserving (DRP) algorithms to minimize the numerical dispersion error in large-scale three-dimensional (3D) finite-difference time-domain (FDTD) simulations. The dispersion error is first expanded in spherical harmonics in terms of the propagation angle and the leading order terms of the series are made equal to zero. Frequency-dependent FDTD coefficients are then obtained and subsequently expanded in a polynomial (Taylor) series in the frequency variable. An inverse Fourier transformation is used to allow for the incorporation of the new coefficients into the FDTD updates. Butterworth or Chebyshev filters are subsequently employed to fine-tune the FDTD coefficients for a given narrowband or broadband range of frequencies of interest. Numerical results are used to compare the proposed 3D DRP-FDTD schemes against traditional high-order FDTD schemes.     

不同注F剂量与CMOS运放电路辐照损伤的相关性

在不同注F剂量条件下,对P沟和N沟两种不同差分对输入CMOS运放电路的电离辐照响应进行了研究.分析比较了注F和未注F运放电路电离辐照响应之间的差异.结果表明,在栅场介质注入适量的F,可有效抑制辐照感生的氧化物电荷尤其是界面态的增长,从而提高CMOS运放电路的抗辐照特性.