基于L1输出反馈自适应方法的火箭姿态控制

针对运载火箭刚—弹耦合动力学模型,开展了基于L1输出反馈自适应方法的火箭姿态控制器设计.考虑到L1控制器低通滤波器环节可能在一定程度上减少弹性影响,分析了火箭不同低频模态对控制系统的影响情况.由于低通滤波器带宽与系统带宽存在相互制约关系,当无法通过低通滤波器设计消除低阶弹性影响时,结合校正网络设计L1输出反馈控制器.仿真结果表明,上述设计思路能够应对火箭低阶弹性问题,所设计的控制器控制效果良好,且在弹性频率变化时系统依然具有良好的暂态和稳态性能.     

Attack Technology Research for Web Service

Web service is characterized by its isomerism and loose coupling;thus greatly fa- cilitate the application of operation in distributed situation, but its disadvantages cause seri- ous safety problems. The principium and characteristic of Web service classical attack tech- nology are expatiated, classical attack techniques are classified, and attack technology is sim- ulated, and then, the directions and the future of Web security are discussed.     

岸吊焊缝裂纹分析与改进措施研究

从材料的焊接性能、焊接结构、焊条、预热与焊后热处理、焊接工艺参数等角度对岸吊胎架焊缝裂纹进行了分析,提出了改进措施,取得了良好的效果。     

Performance of positive and negative electrodes in amorphous manganese oxide supercapacitor

Using potassium permanganate and acetic manganese as the reactants, amorphous manganese oxide was prepared with mechanochemical method. XRD was used for microstructure characterization, while cyclic voltammetry and constant current charge-discharge were used for electrochemical performance testing. The positive electrode （PE） and negative electrode （NE） were investigated respectively in amorphous manganese oxide supercapacitor, aiming to find their different performances in charging-discharging. The results show that the crystalline structure is destroyed in both the PE and NE material during charge-discharge process. Thereinto, the NE suffers a bit more seriously. When cycling, the PE potential scope diminishes while the NE potential scope enlarges. The increased inner resistance makes the NE curves almost bended to be a right angle, but not the PE curves. The cell＇s equivalent series resistance （ESR） is more dependent on the NE, and the capacitance is mainly determined by the rapid descent of the NE potential range. The capacitances of the NE are highly rate-dependent, decreasing from 121.3 to 53.1 F/g, by 56.2%, over the range of 5-25 mV/s. However, the PE appears to be weakly dependent and its capacitance is only dropped by 22.1%.     

铜金粉的颜色及其影响因素

利用分光光度计对国内外铜金粉的颜色进行了测试，研究了铜金粉的成分、微观状态对颜色的影响。结果表明：铜金粉颜色可以用色彩三要素进行描述，其中铜金粉的色相只与合金成分有关，而与铜金粉片的大小、形状及粒度分布无关；明度和纯度与铜金粉片在油墨层中定向排列状态、片的大小、形状及粒度分布有关，而与成分无关；合金成分的微小波动不会引起铜金粉色相的明显改变。     

统计过程控制(SPC)在龙滩水电站混凝土生产质量控制中的应用

混凝土生产工艺流程复杂,控制工序多,生产过程除易受系统因素影响外,还受随机因素的干扰较大,生产质量不易控制,本文应用统计过程控制(SPC)在龙滩水电站混凝土生产中的质量控制实践来谈点初浅的认识.     

水下悬浮隧道锚索涡激动力响应分析

为研究涡激振动和参数振动共同作用下水下悬浮隧道锚索的振动响应,考虑锚索的几何非线性,将管体对锚索的作用简化为轴向激励,建立了悬浮隧道锚索非线性涡激振动方程,并用伽辽金法和龙格-库塔法对悬浮隧道锚索进行数值求解,分析了锚索产生涡激谐振、参数共振时跨中位移响应和轴向力的改变幅度,以及锚索倾斜角度对其振动特性的影响。研究结果表明,锚索产生涡激谐振和参数共振时跨中位移和轴向力大幅增大;垂度效应使得锚索的跨中位移关于平衡位置呈现出不对称性;随着锚索倾角的增大,锚索跨中位移偏移值、一阶固有频率、一阶频率锁定流速都逐渐减小。     

蒸汽发电系统的优化

介绍蒸汽发电系统的优化方法,以及时侦测、剔除和校正误差数据,有效保障发电机组正常运行.     

基于概念的形状分类与识别

基于内容的图像检索已经成为图像检索的一个重要研究方向。其中利用形状特征可以实现形状较为明显的各类图像库的检索。该文对图像形状特征的提取和描述方法进行了较深入地研究,选取其中一部分特征值,分别利用BP神经网络和支持向量机进行形状识别,取得令人满意的实验效果。