电子镇流器的电磁兼容问题研究

电磁兼容是目前电子镇流器最需要解决的问题之一。介绍了电子镇流器产生的辐射干扰、传导干扰及电流谐波畸变干扰的形成和所造成的影响,分析了产生这些干扰的原因,并分别给出了抑制这些干扰的方法,最后就电子镇流器设计制造中的难点问题作了简要说明。     

Wave drift force in a two-layer fluid of finite depth

Based on the momentum and energy conservation principles, a compact calculation formula is analytically derived for the wave-drift force on a 2-D body floating in a two-layer fluid of finite depth. In a two-layer fluid, two different wave modes (the surface-wave mode with longer wavelength and the internal-wave mode with shorter wavelength) exist not only in the incident wave but also in the body-scattered wave, and these wave characteristics are properly incorporated in the obtained formula. It is noted that, unlike the single-layer case, the wave-drift force can be negative in the incident wave of surface-wave mode, if the transmitted wave with internal-wave mode is large. Numerical computations are implemented for a Lewis-form body by means of the boundary-integral-equation method with Green’s function for the two-layer fluid problem. The effects of density ratio, interface position, and body motions on the wave-drift force are studied, and some important features are found for two-layer fluids.     

与客户建立互惠互利长期稳定的营销关系

在我国加入WTO之后，国内钢铁企业与经销商之间如何实现互惠互利，并建立起长期稳定的营销关系。     

一种基于模式搜索的大尺寸测量移站坐标转换方法

针对空间大尺寸测量的移站坐标转换，提出了最小二乘坐标转换数学模型和基于模式搜索的参数求解方法，实验证明该方法具有理论正确性和实际可行性。     

Modeling study of migration-driven lateral instability in autocatalytic systems

The lateral stability of reaction fronts in simple autocatalytic models with the components carrying various charges is investigated when the system is exposed to an inhomogeneous electric field parallel to the direction of propagation. The enhanced migrational flux of the reactant destabilizes the planar front giving rise to a cellular structure because the electric field strength is greater on the reactant side of the reaction front. The onset of instability depends not only on the charge difference between the reactant and the autocatalyst but also on the variation of specific conductance in the course of the reaction, which results in a difference in electric field strength on the opposite sides of the reaction front.     

Relation between microstructure, properties and spark plasma sintering (SPS) parameters of pure ultrafine WC powder

A combined experimental/numerical methodology is developed to fully consolidate pure ultrafine WC powder under a current-control mode. Three applied currents, 1900, 2100 and 2700 A, and a constant pressure of 20 MPa were employed as process conditions. The developed spark plasma sintering (SPS) finite-element model includes a moving-mesh technique to account for the contact resistance change due to sintering shrinkage and punch sliding. The effects of the heating rate on the microstructure and hardness were investigated in detail along the sample radius from both experimental and modeling points of view. The maximum hardness (2700 HV10) was achieved for a current of 1900 A at the core sample, while the maximum densification was achieved for 2100 and 2700 A. A direct relationship between the compact microstructure and both the sintering temperature and the heating rate was established.     

综合线损分析系统研究

描述了综合线损分析系统应该具有的主要功能和分析内容，介绍了系统实现中应该注意的几个问题、系统内容和实现方法。     

Plastic instability in dual-pressure tube-hydroforming process

The tube-hydroforming process has become an indispensable manufacturing technique in recent years. Successful tube hydroforming requires bulging to take place without causing any type of instability such as bursting, wrinkling or buckling. The dual-pressure tube-hydroforming process was introduced to achieve a favorable tri-axial stress state in the deformation process. In this paper, the effect of applying counter pressure on plastic instability of thin-walled tubes is analyzed. It is concluded that in dual-pressure tube hydroforming, the onset of plastic instability is delayed and the ductility of the metal is increased.     

关于传统与现代设计理念的思考

中国传统的思维方式深深地影响了中国传统陶瓷艺术设计，中国传统陶瓷艺术设计的历史脉络清晰，深入到设计思维系统的深层，才有助于我们对当前的陶瓷设计作出有效的转化。现代陶瓷设计的观念是对传统陶瓷文化的延续和发展，深入挖掘传统思维方式的源头活水，才是发展中国现代陶瓷设计的关键。     

垂直定向液晶光阀及光电特性的研究

系统地讨论了排列相畸变模式液晶光阀结构，原理和制作，结合实际测试对其等效电路和电学匹配进行了分析，详细讨论了它的光电特性及相互关系，实测的液晶垂直排列方式工作的液晶光阀性能指标为，分辨率大于５０ｌｐ／ｍｍ，白光输入灵敏度为６．７７μＷ／ｃｍ＾２，响应时间为２００ｍｓ／３００ｍｓ，白光输出对比度为２００：１。