热氧老化EPR电缆绝缘局部放电特性及劣化机理

为了探究热氧老化后乙丙橡胶电缆绝缘的局部放电特性及劣化机理,文中通过典型柱–板电极对不同老化程度的乙丙橡胶试样进行了局部放电试验,并对其放电发展特性和材料理化性质进行了分析。结果表明:放电起始电压和闪络电压均随绝缘老化程度的提高而降低;根据放电过程中放电特征量的变化规律,可将放电过程划分为4个阶段:起始阶段、发展阶段、持续阶段、预闪络阶段,且不同老化程度试样的PRPD谱图在各阶段呈现出特定形状;老化后的试样表面气化或气体解吸附、内部添加剂成分析出导致试样表面出现"沟壑区"、白色块状物和"微孔",分子结构中的羰基等含氧基团、聚乙烯和聚丙烯等自由基数量的增加是乙丙橡胶绝缘在热氧老化后更易出现局部放电的关键原因。     

Lithium-ion battery remaining useful life estimation based on fusion nonlinear degradation AR model and RPF algorithm

The lithium-ion battery cycle life prediction with particle filter (PF) depends on the physical or empirical model. However, in observation equation based on model, the adaptability and accuracy for individual battery under different operating conditions are not fully considered. Therefore, a novel fusion prognostic framework is proposed, in which the data-driven time series prediction model is adopted as observation equation, and combined to PF algorithm for lithium-ion battery cycle life prediction. Firstly, the nonlinear degradation feature of the lithium-ion battery capacity degradation is analyzed, and then, the nonlinear accelerated degradation factor is extracted to improve prediction ability of linear AR model. So an optimized nonlinear degradation autoregressive (ND–AR) time series model for remaining useful life (RUL) estimation of lithium-ion batteries is introduced. Then, the ND–AR model is used to realize multi-step prediction of the battery capacity degradation states. Finally, to improve the uncertainty representation ability of the standard PF algorithm, the regularized particle filter is applied to design a fusion RUL estimation framework of lithium-ion battery. Experimental results with the lithium-ion battery test data from NASA and CALCE (The Center for Advanced Life Cycle Engineering, the University of Maryland) show that the proposed fusion prognostic approach can effectively predict the battery RUL with more accurate forecasting result and uncertainty representation of probability density distribution (pdf).     

基于稀疏表示分类器的和弦识别研究

和弦识别作为音乐信息标注的基础,在分析音乐结构和旋律方面具有非常重要的作用.结合音乐理论知识,提出一种基于稀疏表示分类器的和弦识别方法.与传统的基于帧的识别方法不同,以节拍作为和弦变化的最小时间间隔,利用CQT (Constant-Q Transform)变换对音乐信号进行时频分析,提取PCP (Pitch Class Profile)特征,采用稀疏表示分类器(Sparse Representation-based Classification,SRC)进行和弦识别.实验结果表明,提出的特征和识别方法在识别率上均高于传统的方法.     

基于内点法考虑风电穿透率的区域间可用输电能力研究

根据鼠笼异步风力发电机（SCIM）无功功率对机端电压和有功功率的表达式,修正了原-对偶内点法中的雅可比矩阵和海森矩阵,协调了算法的计算精度与迭代效率。采用连续潮流法计算了不同节点的穿透功率极限,得到SCIM和恒功率因数控制的双馈感应风力发电机（DFIG）不同穿透率下的可用输电能力（ATC）值。仿真结果表明,联络区域节点接入风电场大幅提升送电区与受电区间的ATC,而对于送电区的风电接入情况结论相反;DFIG的功率因数对ATC有较大的影响;通过合理的补偿措施可解决某些并网方式下算法收敛于局部最优解的问题,多节点电压越限为陷入局部最优的主因。     

基于内点法考虑风电穿透率的区域间可用输电能力研究

根据鼠笼异步风力发电机（SCIM）无功功率对机端电压和有功功率的表达式,修正了原-对偶内点法中的雅可比矩阵和海森矩阵,协调了算法的计算精度与迭代效率。采用连续潮流法计算了不同节点的穿透功率极限,得到SCIM和恒功率因数控制的双馈感应风力发电机（DFIG）不同穿透率下的可用输电能力（ATC）值。仿真结果表明,联络区域节点接入风电场大幅提升送电区与受电区间的ATC,而对于送电区的风电接入情况结论相反;DFIG的功率因数对ATC有较大的影响;通过合理的补偿措施可解决某些并网方式下算法收敛于局部最优解的问题,多节点电压越限为陷入局部最优的主因。     

基于SO-GP的智能车间组合调度规则挖掘

针对智能车间复杂性程度高、动态不确定性明显、对调度的实时性要求高以及车间机理模型难以描述等特点,对智能车间实时调度问题展开研究,提出一种将仿真优化与遗传规划(SO-GP)算法相结合的调度规则挖掘方法,在优化生产性能的同时满足实时调度的需求.在SO-GP方法设计中,采用二叉树的结构编码,每个GP个体代表一个组合调度规则,并借助仿真获得个体的适应度值.为了进一步提高挖掘过程的时间效率,对构成GP算法的终止集进行了归一化改进.最后以MiniFAB半导体生产线模型为对象进行实验,验证了所提方法的有效性.     

Phase Formation of the Yttrium Aluminates in the Y<Subscript>2</Subscript>O<Subscript>3</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiC System

Phase formation sequence of the yttrium aluminates in the Y₂O₃-Al₂O₃-SiC ternary system as temperature increases were investigated via x-ray diffraction (XRD). Results showed that YAM (monoclinic), YAP (perovskite) and YAG (garnet) were the yttrium aluminates presented in the solid-state reacted samples at a fixed Al₂O₃:SiC ratio of 1:1. Formation of the yttrium aluminates depended on the temperature. The YAM, YAP and YAG started to form below 1150 °C, at 1300 °C, and at 1450 °C, respectively. Accordingly, two behavior phase diagrams of the Y₂O₃-Al₂O₃-SiC ternary system were recognized, one is in the temperature range of 1150-1300 °C and the other is in 1300-1450 °C, respectively. Thereafter, the phase equilibrium was reached in the temperature range of 1450-1700 °C. Effects of SiC on the phase formation processes in the ternary system were discussed.     

基于视觉显著性的可见红外图像融合

多波段图像融合可以有效综合各个波段图像中包含的特征信息。针对可见光-红外图像,本文提出了一种结合红外图像视觉显著性提取的双波段图像融合方法,一方面旨在凸显红外图像的目标信息,同时又能尽可能的保留可见光图像的丰富细节信息。首先,在局部窗口内实现红外图像的显著性图提取,并通过窗口尺寸的变化形成多尺度的显著性图,并对这些显著性图进行最大值的优选叠加,以获取能反映整幅红外图像各个尺寸目标的显著性图;其次,通过结合显著性图与红外图实现显著性图的加权增强;最后,利用增强的红外显著性图进行双波段图像的融合。通过两组对比实验,数据表明该方法给出的融合图像视觉效果好,运算速度快,客观评价值优于对比的7种融合方法。