定电流对LED的重要性

高功率超高亮度LED已经开始大量应用.要实际体现LED(尤其是高功率超高亮度LED)的优点,采用定电流驱动方式必要条件之一.     

Accurate Cross Sections for Microanalysis

To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction of ionizations events producing x rays of interest and the absorption coefficient of the x rays on the path to the detector. The theoretical predictions and experimental data available for ionization cross sections are limited mainly to K shells of a few elements. Results of systematic plane wave Born approximation calculations with exchange for K, L, and M shell ionization cross sections over the range of electron energies used in microanalysis are presented. Comparisons are made with experimental measurement for selected K shells and it is shown that the plane wave theory is not appropriate for overvoltages less than 2.5 V.     

Mechanoluminescent pulse pressure sensors. Processing of output optical signal

The process of mechanoluminescence transformation of a pulse pressure sensor is considered. The process consists in excitation of emission under the action of mechanical loading. An algorithm for use in processing the output optical signal of the sensor that makes it possible to determine an input shock pulse is presented. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 28–31, October, 2007.     

轻钢结构浅析

轻钢结构作为一种新型结构在近几年发展很快，应用范围也日趋广泛。主要针对轻钢结构的特点，结合实际工程设计，对轻钢结构现状、发展进行了阐述和分析。     

用改进的逐次逼近解法计算二维井间电磁场

提出了一种计算积分方程的新方法——改进的逐次逼近解法 (MSAM) ,并用该方法计算了轴对称二维井间电磁场。与传统的逐次逼近解法 (SAM)相比 ,该方法收敛性强 ,应用范围广 ,可适用于高电导率对比地层。由于不必进行直接的大型矩阵求逆运算 ,因此与积分方程的直接解法 (IE)相比 ,该方法计算速度更快 ,所需内存更少。采用矩阵求逆方法计算了成层介质中的二维 Green函数 ,并对含 Green函数的积分进行了简化 ,从而加快了计算速度。数值计算结果显示 ,在地层电导率对比度达到 2个数量级时 MSAM仍收敛 ,且计算结果与直接求解积分方程的结果一致 ,因此 MSAM是一种有效的计算轴对称二维井间电磁场的方法     

A unified proposal for characteristic testing methods and figure of merit of 8‐kV/3.5‐kVA class light‐triggered thyristors

Power devices with high capability have been developed. 8‐kV/3.5‐kA‐class light‐triggered thyristors have the highest capability among power devices. These devices are used in the Kii Channel HVDC transmission system in Japan. In this paper, we report the extracted problems of conventional testing methods of 8‐kV/3.5‐kA‐class light‐triggered thyristors among manufacturers, and the proposed unified testing methods on the basis of element characteristics and operating conditions in the Kii Channel HVDC system. Furthermore, we propose a figure of merit for power devices for the practical use, and try to extract elements used at the Kii Channel HVDC system with small margins and low withstand capabilities. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 61–70, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10024     

MGD工艺技术的特点

应炼油厂要求，FCC既要多产柴油，又需多产液化气，石油化工科学研究院开发了MGD工艺。该工工艺遵循催化裂化的反应机理，把分段进料和汽油回炼紧密组合为一个体系，较好地达到了用掺渣油原料多产柴油和液化气的目的，其汽油烯烃和硫含量降低。从而使炼油厂调合汽油达到产品规格。工艺实施容易，改造投入少、见效快，受到炼油厂欢迎，并迅速推广应用。浅释了MGD工艺的反应机理，并提出了应用中应该注意的问题。     

加氢润滑油基础油光安定性研究进展

加氢处理基础油与溶剂精制基础油相比具有硫、氮含量低，颜色浅，粘度指数高，挥发性低，饱和烃含量高，对添加剂的感受性好等优点。但是，加氢处理润滑油基础油的一个明显缺点就是其光安定性差，即在有氧条件下通过光照（有时也需加热），油品颜色加深、透明度变差，继而有絮凝物或沉淀生成。文章综述了国内外有关加氢润滑油基础油光安定性的原因和解决办法的研究进展情况。     

体积-表面淬火中加热温度的自动控制

根据表面-体积淬火奥氏体规范的要求，分析了感应加热过程中温度控制的特点和方式，并介绍了采用红外线光导纤维测温和微机控温技术成功用于体积-表面淬火中透热温度的自动控制。