电压型PWM高频整流器统一数学模型及系统仿真

引用交流电机统一理论中的空间坐标系变换概念,建立了电压型PWM高频整流器系统统一数学模型。基于该模型,提出一种系统动态的仿真结构及相应的仿真算法,并运用于高频整流器系统的仿真分析中。样机实验和仿真分析的结果证明了该统一数学模型的正确性。     

Magnetite‐coated polystyrene hybrid microspheres prepared by miniemulsion polymerization

Hybrid microspheres with a polystyrene core coated with magnetite nanoparticles were prepared by miniemulsion polymerization. Acrylic acid was used as a comonomer to promote the anchoring of the magnetite nanoparticles onto the polymeric surface. The addition of a hydrophobic agent prevents effectively the monomer from diffusing into the aqueous phase. Magnetite was treated with a silane coupling agent in order to introduce some interactions with the polymers. The morphology and the structure of the hybrid microspheres were characterized using X‐ray diffraction, infrared spectroscopy, transmission electron microscopy and thermogravimetric analysis. The results show that the morphology of the hybrid microspheres was influenced by the concentrations of acrylic acid, hydrophobic agent and surfactant, and that the degree of coating can be tuned by changing these parameters. The miniemulsion polymerization technique is adaptable to the synthesis of magnetite‐coated polymer particles, and the synthesis can be scaled up. Copyright © 2008 Society of Chemical Industry     

Research on the path-following control of rubber-tire trackless train with bogies

Journal of Mechanical Science and Technology - Aiming at the light rail train with rubber wheel bogies, a path-following control scheme based on road line recognition was proposed. The...     

基于超变量设计的机械设计自动化系统

现代CAD技术面向设计自动化，但现存的基于约束的机构设计设计自动化（MDA）系统在某些方面存在缺陷。提出基于超变量设计技术（VGX）的MDA系统，VGX技术以混合求解策略为核心，支持超越历史的设计，并采用了交互性很强的拖放造型技术，完全的数学描述使基于VGX技术的MDA系统不需要单独建模就能进行3D公差，机构等数学分析。     

Computer aided examination of I2L structures

A structure-oriented physico-topological; model of the I²L gate is described. The mode parameters (saturation currents, base resistance, current gains) have been calculated from doping levels, geometrical and electronic parameters. The turn-over level of the transfer characteristic and the propagation delay time dependence on main technological parameters, temperature and neutron irradiation have been investigated. The temperature and neutron irradiation dependence of the transfer surface and of the dynamic behaviour of the 1²L flip-flop has also been examined. The calculations have been done with the non-linear circuit analysis program TRANZ-TBAN.     

非晶态Ni—Si—B系合金在FeCl3溶液中的腐蚀行为

用失重法研究了几种Ｎｉ－Ｓｉ－Ｂ系合金在ＦｅＣｌ３溶液中腐蚀行为，分别考查了腐蚀速率与材料组分，表面状态，溶液温度，浓度及ｐＨ值的关系。结果表明：随着Ｎｉ含量增加，表面状态越粗糙，溶液浓度增加，温度升高，ＰＨ值降低，均将使腐蚀速率增加。     

提高三氯异氰尿酸质量的方法

分析了影响三氯异氰尿酸质量的几个因素，并提出了包括保证原料质量、准确配制及过滤中间体、提高搅拌效率、采用双通氯管、适当控制pH值及反应温度等的解决措施。     

Korean-English biliteracy acquisition: Cross-language phonological and orthographic transfer.

Cross-language phonological and orthographic relationship in the biliteracy acquisition of children learning to read Korean and English was investigated in this study. Forty-five Korean-English bilingual children were tested in first-language (L1; Korean) and 2nd-language (L2; English) reading skills focusing on 2 reading processes--phonological and orthographic processing. The authors found that phonological skills in L1 and L2 were strongly correlated, and Korean phonological skills explained a unique amount of variance in English pseudoword reading beyond English phonological and orthographic skills. However, there was limited orthographic skill transfer between the 2 systems. Results are discussed within the framework of universal phonological processes in learning to read. The authors conclude that bilingual reading acquisition may be a joint function of general phonological processes and orthographic-specific skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)