苯并噁嗪树脂在绝缘材料中的应用研究

苯并噁嗪树脂是一种新兴的热固性树脂,拥有良好的阻燃性能、耐热性能和力学性能等,具有广阔的应用前景和较高的研究价值。本文概述了苯并噁嗪树脂的化学结构和聚集态结构,分析了结构对树脂介电性能的影响,重点介绍了苯并噁嗪复合材料的介电性能,并对苯并噁嗪树脂在电子电器领域更广泛的应用进行了展望。     

聚苯乙烯/纳米碳化硅晶须复合材料的制备

采用钛酸酯偶联剂(NDZ-105)对纳米β-碳化硅晶须(β-SiCw)进行表面改性处理,通过粉末共混-模压成型制备PS/SiCw纳米复合材料。探讨了SiCw用量和NDZ-105处理对复合材料力学、耐热性和介电性能的影响。结果表明,复合材料的力学性能随SiCw用量的增加而提高,当SiCw的质量分数为3%时,综合力学性能最佳;表面改性有助于进一步提高材料的力学性能;热失重分析表明SiCw的加入使PS的耐热性提高;介电性能分析表明复合材料的介电常数随SiC用量的增加而增加。     

双马来酰亚胺三嗪树脂改性研究进展

综述了双马来酰亚胺三嗪树脂(BT树脂)改性技术的研究现状和最新研究进展,包括:结构改性-可交联活性基团的引入、互穿聚合物网络技术引入其它改性树脂、共聚改性和共混改性.论述了经二烯丙基双酚A、环氧树脂、聚苯醚等改性后的BT树脂,其介电性能、耐高温性、加工工艺性及其对玻璃纤维的浸润性等性能的变化.介绍了BT树脂改性发展方向及其在高性能印制电路板(PCB)应用中存在和急需解决的问题.     

烯丙基甲酚改性BMI的研究

本文介绍了烯丙基甲酚以及用它改性BMI所得树脂体系的性能如胡溶性、粘度、反应性、力学性能和耐热性等。对树脂体系在无溶剂浸漆和玻璃布层压板方面的应用进行了讨论。结果表明，烯丙基甲酸可有效地降低BMI的粘度，与BMI的反应性好，团化树脂及玻璃布层压板具有良好的力学性能、耐热性和绝缘性能。     

环氧树脂/DDS固化剂体系介电常数和介质损耗因数的研究

1 前言 环氧树脂由于具有较好的粘合性、电绝缘性、耐化学药品性,且强度高、耐热高、粘附力强、收缩性好、稳定性高、适应性强和工艺性好,在电气、化工等领域得到了广泛应用,而固化过程直接影响其应用效果[1].环氧树脂固化过程对其耐热性和机械性能的影响已经有大量的研究成果[2],但在树脂介电性能方面则少见报道.     

二烯丙基双酚A改性双马来酰亚胺树脂基覆铜板的研制

采用二烯丙基双酚A(DABPA)对4,4'-双马来酰亚胺基二苯甲烷(BMI)进行改性,然后与环氧树脂和4,4'-二氨基二苯砜(DDS)共混制得覆铜板,并对改性BMI树脂和覆铜板分别进行了结构表征和性能测试。结果表明:研制的覆铜板阻燃等级达到V-0,并具有较好的介电性能、耐热性能以及力学性能。     

芳烷基酚树脂及其玻璃布层压板的制备

研究用二甲苯甲醛树脂、苯酚和甲醛等合成热固性芳烷基酚树脂以及用该树脂制备玻璃布层压板的工艺方法，通过热失重(TGA)曲线研究树脂的耐热性，对所制层压板的机械性能和电性能进行检测，结果表明芳烷基酚玻璃布层压板具有H级的耐热性能，其机械性能和电性能均满足H级层压板的使用要求。     

复合材料用苯并噁嗪树脂的研究进展

本文首先概述了苯并噁嗪树脂在耐热性、韧性、阻燃性、介电性能等方面的改性进展,然后重点阐述了苯并噁嗪树脂在预浸料、RTM、拉挤成型等复合材料成型工艺中的应用进展,介绍了苯并噁嗪树脂基复合材料在航空航天、电子电器和交通运输领域的应用。最后,展望了苯并噁嗪树脂在复合材料领域的发展趋势。     

烯丙基甲酚改性BMI的研究

本文介绍了烯丙基甲酚以及用它改性ＢＭＩ所得树脂体系的性能如相溶性，粘度，反应性，力学性能和耐热性等。对树脂体系在无溶剂浸漆和玻璃布层压板方面的应用进行了讨论。结果表明，烯丙基甲酚 可吸效地降低ＢＭＩ的粘度，与ＢＭＩ的反应性好，固化树脂及玻璃布层压板板具有良好地力学性能，而热性和绝缘性能。     

芳烷基酚聚酰胺玻璃布层压板的研制

将二甲苯甲醛树脂、苯酚和甲醛等合成热固性芳烷基酚树脂，再与聚酰胺-酰亚胺树脂混合，得到的树脂用于制备玻璃布层压板。经对该层压板的机械性能和电性能进行检测，结果表明芳烷基酚聚酰胺玻璃布层压板具有H级的耐热性，其机械性能和电性能均满足H级层压板的要求。     

Capacitor voltage balancing in cascaded H-bridge multilevel inverter and its modelling analysis for grid integrated wind energy conversion system application

In this study, a comprehensive control scheme for cascaded H-bridge multilevel inverter (CHBMLI)-based grid integrated bulk wind energy conversion system (WECS) addressing the problem of deviation of wind speeds among windmills like a partial shading condition of PV system is presented. The proposed control scheme uses independent dc links with reduced voltages that makes such a topology an ideal candidate for high and medium power WECS with improved reliability. Inconsistency of wind speeds at each turbine causes distinct voltage conditions among the isolated dc links of the CHBMLI H-bridge cells (HBC) leading to unstable power generation. The projected scheme along with maximum and efficient energy conversion has the ability of dc link capacitor voltage balancing in each HBC of CHBMLI during the above said power generation mismatch conditions and also maintains power quality in the grid side voltage and injected currents as per standards. Moreover, the modelling analysis of the adopted CHBMLI for the grid integrated WECS application has also been derived. The system performance under inconsistent wind speed environment has been tested and analysed by using MATLAB simulation and validated by using FPGA-based real-time simulator (Opal-RT-OP5700).     

New design for the high-performance drive system for DC brushless motor

The dc brushless motor, permanent magnet-type synchronous motor (PM motor), has been used widely in industrial robots, the machine tools for factory, and factory automations. Therefore, it is more desirable to improve the performance of the PM motor variable speed control system. Although only the torque component current is adjusted as the control method for the PM motor, so-called Vector Control, it is expected that the developed characteristics will be added to the PM motor. In this paper, new driving methods for the PM motor and a new design method for the variable speed control system are presented. The new motor driving methods which bring to the PM motor a new driving performance, e.g., a quick transient response or high-efficiency motor driving, can be implemented by controlling not only the torque component current, but also the magnetizing component current. A developed optimal control theory, i.e., the error system technique, is employed for designing the control system. The control law is endowed with a steady robustness against the variation of the system parameters and the ability of compensating the delay time due to the control processing. The effectiveness of the proposed method is confirmed by simulations and experiments.     

遗传算法在冗余系统可靠性最优分配问题上的应用

以前在串——并联冗余系统可靠性的最优分配问题上，总是把部件的可靠度看成是一个确定的值。论文从另外的角度，在遗传算法的基础上，把部件的可靠性和平均失效时间看成是随机变量，使得对这类问题的分析上得到了很好的解决。     

A new approach for power system online DSA using distributed processing and fuzzy logic

In this paper, a new approach for power system online dynamic security assessment, as well as a tool for calculating the proposed fuzzy dynamic security index is presented. This proposal is based on a three-stage fuzzy inference system, which composes the fuzzy dynamic security index making use of seven performance indexes herein defined. The calculation of the performance indexes is based on the results obtained through dynamic simulations of the system behaviour after each one of the credible contingencies in a given operation state. With the aim of reducing the calculation time a novel distributed processing of the dynamic simulations is also developed. High voltage systems are used to illustrate the ideas presented in the paper.     

叶片间距对五级叶片百叶窗煤粉浓缩器性能的影响

水平浓淡燃烧技术作为先进的煤粉燃烧技术,可以使锅炉同时达到稳燃、高效、防腐蚀结渣和低污染排放等方面的要求。作为水平浓淡燃烧技术的关键部件,百叶窗煤粉浓缩器性能的好坏直接影响到煤粉炉中煤粉燃烧的效果。该文利用百叶窗浓缩器实验装置研究了叶片间距对5级叶片百叶窗浓缩器性能的影响。实验结果表明：靠前的叶片对浓缩率影响较大,中间及末级叶片对阻力系数影响较大。各级叶片间距比为1:1:1:3时具有最大浓缩率和居中的阻力系数,可满足对浓缩效果要求较高的浓缩器;1:2.25:1:1结构可满足对阻力要求较高的浓缩器。实验结果为百叶窗浓缩器的设计和工业化应用提供了理论依据。     

Dynamic Response of a Two-Conductor Bundle to Eolian Excitation

This paper describes the required formulations and the various stages involved in calculating the dynamic response of a two-conductor bundle equipped with flexible articulated spacers to eolian excitation generated by the wind on a conductor by the alternative lift forces as a result of so-called Von Karman vortices. The formulations take into account both the damping that exists in the conductors and spacers and the inertial characteristics of the latter.The analytical model developed, which is based on the transfer matrix method, allows the following parameters to be calculated for each eigenvalue of the matrix of the generalized stiffness of the spacer: the resonance frequencies of the bundle and corresponding characteristic distribution, the eolian power induced in the conductors and dissipated in the latter and in the spacers, for each vibration mode of the system, and the equilibrium amplitudes along the span length for which the power induced in the system is equal to that dissipated.The formulations developed during the course of this work were computerized and applied to the case of a two-conductor bundle. The results of these calculations are presented.     

Comparison of security constrained economic dispatch formulations to incorporate reliability standards on demand response resources into Midwest ISO co-optimized energy and ancillary service market

The purpose of this paper is to analyze three formulations developed to facilitate participation of demand response resource Type-1 in the Midwest ISO's co-optimized energy and ancillary service market. While these three formulations appear similar on the surface, careful analysis will show that they can have different impacts on clearing and pricing outcomes. Based on this analysis, the formulation that can maintain reserve product priority and reserve clearing price order is selected and implemented in the Midwest ISO Security Constrained Economic Dispatch (SCED) and Security Constrained Unit Commitment (SCUC) market clearing processes. A 5-bus system is used to illustrate the features of each approach. This paper focuses on SCED formulations. The impact from the discussed formulations on SCUC should be similar.     

超宽带信号在运动人体下阴影衰落对 通信性能的影响

超宽带信号在人体通信技术中具有低功耗、抗衰减等优势。针对人体信道建模工作中阴影衰落与运动状态关联性的问题,文章基于人体不同运动姿态与组织电磁特性建立人体模型,分析超宽带信号下的动态人体信道阴影衰落特性。首先,通过建立80条数据传播链路分析人体不同状态下的体表传播特性,给出了一种体表传播距离与路径损耗的二阶指数衰减关系。其次,分析了动态模型组织电特性变化对路径损耗的影响情况。最后,使用平均误码率研究了UWB系统在动态阴影衰落下的性能差异。结果表明,在动态人体模型下UWB频段的抗损耗性能优于HBC频段,其阴影衰落强度受运动状态影响程度强于HBC频段。研究对超宽带信号在人体通信的建模、应用工作中提供了动态人体阴影衰落强度分布的理论基础。     

An improved P300-based brain-computer interface.

A brain-computer interface (BCI) is a system for direct communication between brain and computer. The BCI developed in this work is based on a BCI described by Farwell and Donchin in 1988, which allows a subject to communicate one of 36 symbols presented on a 6 x 6 matrix. The system exploits the P300 component of event-related brain potentials (ERP) as a medium for communication. The processing methods distinguish this work from Donchin's work. In this work, independent component analysis (ICA) was used to separate the P300 source from the background noise. A matched filter was used together with averaging and threshold techniques for detecting the existence of P300s. The processing method was evaluated offline on data recorded from six healthy subjects. The method achieved a communication rate of 5.45 symbols/min with an accuracy of 92.1% compared to 4.8 symbols/min with an accuracy of 90% in Donchin's work. The online interface was tested with the same six subjects. The average communication rate achieved was 4.5 symbols/min with an accuracy of 79.5 % as apposed to the 4.8 symbols/min with an accuracy of 56 % in Donchin's work. The presented BCI achieves excellent performance compared to other existing BCIs, and allows a reasonable communication rate, while maintaining a low error rate.     

基于组件的电力系统实时信息处理软件的结构研究

结合分布式计算环境与软件可重用技术的发展,剖析了传统的集中式结构的应用软件氘存在的缺陷和局限性。详细分析了组件技术以及将其应用于电力系统时所面临的实时性问题,在此基础上提出了一适合于电力系统实时信息处理的系统结构。以采用变电站自动化系统为例,比较了其于集中式结构在于组件结构所实现的系统之间的性能差异,表明了所提结构的可行性。同时也指出,标准晃组件应用的基础,因此在开发实时信息处理系统时,要遵循现有