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。     

关于我国钢铁工业发展战略的思考

21世纪初是世界经济发展的重大战略机遇期,如何抓住机遇加快发展,是中国钢铁行业应认真思考的问题。十一五我国钢铁工业的发展,靠什么来拉动,还能靠大规模的投资吗?目前我们还不能生产的双高产品怎么办,靠花钱能买来技术吗?靠市场能换来核心产品吗?值得深思。当今,我们思考的不仅应考虑个别企业的生存问题,而更应考虑的是钢铁行业整体的长远发展问题,即     

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.     

数值试井在白6-2井测试资料分析评价中的应用

数值试井是在近来发展的一项新的试井解释技术，具有处理非均质，复杂边界油气藏问题的优点，弥补了常规解析试井技术的不足。运用数值试井解释技术，结合动、静态资料，通过对白6-1断块白6-2井测试资料的综合分析评价，确定了储层渗流参数，落实了该气藏的边界情况，为该断块下一步开发提供可靠依据。     

工业管道测厚的几点问题探讨

超声波测厚在腐蚀监测上应用越来越广泛,为让这项检测技术更准确、更可靠,充分发挥功效,文章就工业管道测厚中测厚数据处理、测厚点选择、高温问题以及其它影响因素等几个方面进行了探讨。