硅直接键合(SDB)技术在新型电力电子器件应用中的新进展

综述了硅直接键合（SDB）技术在绝缘栅双极晶体管（IGBT）、静电感应晶闸管（SITH）及MOS控制可关断晶闸管（MTO）等器件中的新应用,说明了SDB技术在新型电力电子器件应用中的新方法和新思路。在此基础上,提出了用SDB技术制作集成门极换流晶闸管（IGCT）和集成门极双晶体管（IGDT）的设想,并给出了相应的工艺方案。     

A parallel distributed knowledge-based system for turbine generator fault diagnosis

Real-time fault diagnosis for turbine generators is a fairly complex problem. Parallel processing and distributed artificial intelligence (DAI), as rapidly emerging and promising technologies, provide powerful tools for solving this difficult problem. Based on the study of the basic fault diagnosis process for turbine generators, the idea of parallel processing and DAI is introduced into the field of fault diagnosis. Parallelism at four different levels in the fault diagnosis process is proposed. It lays down the theoretical basis for the development of a real-time parallel distributed fault diagnosing system for the turbine generator of a 300 MW fossil power plant. The diagnostic system can continuously monitor the vibration of the turbine generator as well as various process data.     

紫苏球蛋白乳化性及其O/W乳液的稳定性研究

将紫苏籽粉碎过60目筛后采用石油醚脱脂得到紫苏籽脱脂粉,采用osborne法提取紫苏球蛋白,研究其乳化性质,并将其应用于水包油(oil in water,O/W)乳液,进一步研究紫苏球蛋白浓度对乳液稳定性影响.结果表明,紫苏脱脂粉中球蛋白含量较高,其溶解性、乳化活性和乳化稳定性在pH 2～9,呈现U型曲线;球蛋白质量浓...     

Influence of porosity and fibre coating on engineering elastic moduli of fibre-reinforced ceramics (SiC/SiC)

Porosity generally has a large influence on the modulus of monolithic ceramics. Little, however, is known about its influence in fibre-reinforced ceramics. In the present investigation the influence of porosity on the elastic moduli, i.e. the longitudinal modulus E_L, the transverse modulus E_T and the longitudinal shear modulus G_LT, of unidirectional SiC/SiC ceramic matrix composites is studied. SiC fibres (Nicalon NLM 202) with pyrocarbon coatings of different thicknesses were chemically vapour impregnated by SiC. The axial tensile modulus proved to be little influenced by a porosity content of 13–14%. In fact, the measured modulus was 4–7% smaller than the value predicted with the classical linear rule of mixtures making use of elastic constants of each component and assuming porosity does not reduce the moduli of the different components. On the other hand, the shear and transverse moduli are excessively reduced by the presence of porosity. For a porosity content of 14%, the reduction is roughly 50 and 60% compared with theoretical values for pore insensitive and dense material computed with the model of composite cylinder assemblage and the polarization extremum principle. Finally, the influence of pore morphology on the elastic moduli is discussed.     

基于公交轨迹和定位信息的地域群播算法研究

传统的地域群播算法大多数在WSN中使用,没有考虑到道路路网和车辆轨迹信息,没有很好地适用于车联网中的群播需求。基于目前的一些商业需求,引入了公交车的轨迹信息,提出了一种基于公交轨迹的地域群播算法。第一阶段先建立公交节点的轨迹树以及相遇模型,再根据相遇图计算公交节点对目标区域的消息转发能力,选择具有更高消息转发能力的节点转发消息到目的区域。第二阶段使用稳定性指数来估计两辆车的稳定性,在目的区域的每条街道上建立一个车辆集,通过建立和维护车辆集达到群播的目的。在联合仿真平台SUMO和OMNET++下仿真,其实验结果分析表明,随着车辆数目增加,该算法在维持高的数据包投递率情况下可以将整网的传输开销降低,达到预期的目标。     

H.266/VVC帧内预测模式快速判决方法

为降低新一代高效视频编码标准H.266/VVC的编码复杂度,提出一种快速的帧内预测模式判决方法。从率失真理论的角度出发,分析变换域残差的分布特性,根据标量量化技术对码率的影响推导出编码码率预测模型。结合帧内预测原理,利用当前块预测残差、参考块预测残差及其编码失真提出编码失真预测模型,并根据率失真代价确定最优的帧内预测模式。实验结果表明,该判决方法在保证编码效率的同时约节省了31%的编码时间。     

标准操作冲击电压下220 kV GIS中典型缺陷局部放电特征

通过在实验室搭建的冲击电压下220 kV GIS局部放电测试系统,研究了在220 kV GIS母线段中设置典型缺陷在标准操作冲击电压下局部放电特性.大量试验表明,在标准操作冲击电压下,局部放电具有较工频具有显著性差异.局部放电从PDIV开始就表现出较高的放电脉冲幅值、放电次数以及更宽的放电区域范围,此趋势随着施加电压的上升而越明显,且负极性的放电概率要高于正极性下的放电.