铜铬复合电极电火花小孔加工机理及试验研究

电火花小孔加工中存在工具电极损耗严重、加工速度慢、棱角变钝出现锥度等问题。分析其存在问题的原因,提出采用铜铬复合电极进行电火花小孔加工。分析其加工机理并进行实验,实验结果表明:采用铜铬复合电极进行小孔加工比采用铜电极进行小孔加工能显著提高加工速度,减小锥度和电极相对损耗。     

Experimental investigation on impingement-effusion film-cooling behaviors in curve section

A new series of test pieces with different geometrical configuration and geometry dimensions are designed to experimentally investigate on impingement-effusion cooling behavior in curve effusion wall of combustion chamber. The test results show that the discharge coefficient increased with the increasing blowing ratio. The effusion hole–hole spacing has an effect on the discharge coefficient and the discharge coefficient commonly decreased with the increment of effusion hole–hole spacing. The blowing ratio greatly effects cooling behavior. The bigger blowing ratio is favorable for improving cooling characters. At the curved effusion wall, to begin with, cooling effectiveness increased slowly and kept a steady value in subsequence. But, for the rear end of curved effusion wall, it decreased slowly. With decreasing of effusion hole angle and effusion hole–hole spacing, cooling effectiveness is enhanced. Meanwhile, blowing ratio, effusion angle and effusion hole–hole spacing take an evident effect on the discharge coefficient.     

回流焊温度曲线热容研究

本文全面的分析了回流焊温度曲线在回流焊工艺中的作用，回流焊工艺的工艺特点、影响回流焊温度曲线的各种因素。如何从热容的思想建立回流焊温度曲线的方法？如何调整温度曲线通过控制温度曲线改善工艺过程，减少回流焊工艺的缺陷？     

大厚度碳纤维复合材料层压板的试制

介绍了大厚度碳纤维复合材料层压板研制中的主要技术问题,包括预浸料体系的选用、层压板厚度的控制和无损检测的实施等,为大厚度复合材料层压板的工程化应用打下了基础.     

针对电视／红外导引头的镜面干扰法

随着“空地一体化”和“数字化”作战理论在战争中的应用，以电视／红外制导武器为主的防区外精确打击能力，成为空军现代化水平的主要标志之一。在介绍电视／红外制导空地导弹武器系统末制导段的工作过程和图像跟踪原理的基础上，对电视／红外导引头的特点及其跟踪过程进行了深入分析，得出电视／红外导引头光电干扰的实现方法。针对现有干扰方法的缺点，提出了一种新的光电干扰方法——镜面干扰方法。     

Minimum sliding mode error feedback control for fault tolerant small satellite attitude control

This paper proposes a new control strategy (which we call “minimum sliding mode error feedback control, MSMEFC”) for small satellite attitude control. As we know, the attitude control algorithm plays a significant role in the whole performance of the satellite, especially under the existence of uncertain disturbances from the space. Without loss of generality, the MSMEFC is presented based on the sliding mode theory. It is assumed that the equivalent control error is defined to offset the uncertain disturbances to improve the control performance. Hence, in order to estimate the optimal equivalent control error, a cost function is derived on the basis of the principle of minimum sliding mode error. Then, the equivalent control error wills feedback to the conventional sliding mode control to obtain the final MSMEFC. According to the theoretical analyzes, the sliding mode after the MSMEFC will approximate to the ideal sliding mode, resulting in enhancing the control performance. Moreover, an adaptive non-singular terminal sliding mode is employed to compare with the performance of MSMEFC. Several simulations are performed to verify the effectiveness of proposed MSMEFC in the presence of serious perturbations, even in some fault-tolerant scenarios.     

高职英语教学中形成性评估的应用研究综述

本文收集了形成性评估在高职英语教学中应用研究的文献,进行了分析,总结了前期研究的局限,并对后期研究提出了一些建议。     

三角形截面高柔结构横风向振动的风洞试验研究

本文介绍了正三角形截面高柔结构模型在均匀流场和湍流场中三种迎角下的横风向风振响应风洞试验结果，分析了三角形截面高柔结构的横风向涡激振动现象与驰振危险性，获得了一些数据和结论。     

正常金属与非费米液体间的隧穿

本文先介绍了非费米液体，再利用线性响应理论研究正常金属与非费米液体间的隧道，证明了隧穿电流与电压的关系取决于非费米液体特征，可以不是线性关系。