超低碳含铜时效钢抗裂性研究

采用理论计算、热影响区最高硬度试验和小铁研试验方法研究了超低碳含铜时效钢的抗裂性。结果表明，与强度级别相同的12Ni3CrMoV钢相比，超低碳含铜时效钢具有更为优异的焊接性能，其热影响区淬硬倾向较小，在-5℃～0℃以及低于4000Pa绝对湿度下不预热焊接能够获得良好的焊接性能。     

磁场控制技术在带极堆焊中的应用

带极堆焊中，为提高生产效率多采用宽带极、大电流，因而容易引起焊道成形不良。结合国内外对焊接过程中磁控技术的研究，探讨了焊接电流感应磁场对带极堆焊的不良影响及磁场控制技术在带极堆焊中的应用。实验表明，通过施加外磁场改变熔池金属流向，可有效抑制事极堆焊中的咬边等焊道成形不良问题的产生。     

刮板造型的改进

介绍了对传统刮板造型存在问题所进行的改进.     

Digital arc welding power supply based on real-time operating system

A digital arc welding power supply was designed with the advanced reduced instruction set computer machine （ARM） and embedded real-time multi-task operating system micro C/OS- Ⅱ. The ARM, with its powerful calculating speed and complete peripheral equipments, is very suitable to work as the controller of the digital power supply. The micro C/OS- Ⅱ transplanted in ARM, helps to improve the respondent speed against various welding signals, as well as the reliability of the controlling software. The welding process consists of nine tasks. The tasks of great significance on reliability of the welder, for example, the A/D conversion of current and voltage, enjoy top priority. To avoid simultaneous-sharing on A/D converter and LCD module, two semaphores are introduced in to ensure the smooth performance of the welding power supply. Proven by experiments ,the ARM and the micro C/OS- Ⅱ can greatly improve both the respondent speed and the reliability of the digital welder.     

溶胶-凝胶制备的Al2O3涂层抗原子氧侵蚀性能研究

以异丙醇铝(Al(C3H7O)3)为先驱物,水为溶剂,HNO3做胶溶剂制得了稳定、均一的Al2O3溶胶,浸涂在聚酰亚胺和银薄膜表面干燥后获得了致密透明的涂层.采用空间综合环境地面模拟设备对试样进行了原子氧暴露实验.结果表明:溶胶-凝胶制备的Al2O3涂层抗原子氧侵蚀性能优异,抗原子氧侵蚀性能比聚酰亚胺基体提高了2个数量级以上.经FTIR和XPS分析表明:在原子氧暴露后涂层表面生成了一层Al2O3,阻止了原子氧对基体材料的进一步侵蚀.涂覆涂层后基体的光学性能没有受到影响.实验证明溶胶-凝胶制备抗原子氧侵蚀的防护涂层是一种行之有效的方法.它工艺简单,可涂覆形状复杂、大面积的器件.     

组织状态对循环冲击及非冲击载荷下裂纹扩展的影响

本文对10~#钢和45CrNi合金钢的几种组织状态分别进行了冲击疲劳及非冲击疲劳裂纹扩展试验,结果表明:45CrNi的组织状态对冲击疲劳裂纹扩展的影响较对非冲击疲劳的大;10~#钢的组织状态对两种载荷下的裂纹扩展基本上无影响。结合微观机制和载荷特性,讨论了组织因素对冲击、非冲击疲劳裂纹扩展的影响。     

Global robust output tracking control for a class of cascade nonlinear systems with unknown control directions

We investigate the global robust tracking problem via output feedback for a class of cascade nonlinear systems with dynamic uncertainties and non-vanishing disturbances. It does not require a priori knowledge of the sign of the high-frequency gain. A recursive design scheme is presented using the ideas of pseudosign function, Nussbaum-type gain technique and the deadzone method. It is shown that under some conditions, the tracking error can be guaranteed asymptotic to the interval [?ε, ε]?? with arbitrary prescribed ε>0 after a finite time, while keeping all signals of the resulting closed-loop systems bounded. The simulation results demonstrate the effectiveness of the proposed algorithm.     

Dual–primal proximal point algorithms for extended convex programming

This paper presents a class of dual–primal proximal point algorithms (PPAs) for extended convex programming with linear constraints. By choosing appropriate proximal regularization matrices, the application of the general PPA to the equivalent variational inequality of the extended convex programming with linear constraints can result in easy proximal subproblems. In theory, the sequence generated by the general PPA may fail to converge since the proximal regularization matrix is asymmetric sometimes. So we construct descent directions derived from the solution obtained by the general PPA. Different step lengths and descent directions are chosen with the negligible additional computational load. The global convergence of the new algorithms is proved easily based on the fact that the sequences generated are Fejér monotone. Furthermore, we provide a simple proof for the O(1/t) convergence rate of these algorithms.     

Conditional diagnosability and strong diagnosability of shuffle-cubes under the comparison model

The growing size of multiprocessor systems increases the vulnerability to component failures. It is crucial to locate and replace faulty processors to maintain the system's high reliability. Processor fault diagnosis is essential to the reliability of a multiprocessor system and the diagnosabilities of many well-known networks (such as hierarchical hypercubes and crossed cubes [S. Zhou, L. Lin and J.-M. Xu, Conditional fault diagnosis of hierarchical hypercubes, Int. J. Comput. Math. 89(16) (2012), pp. 2152–2164 and S. Zhou, The conditional diagnosability of crossed cubes under the comparison model, Int. J. Comput. Math. 87(15) (2010), pp. 3387–3396]) have been investigated in the literature. A system is t-diagnosable if all faulty nodes can be identified without replacement when the number of faults does not exceed t, where t is some positive integer. Furthermore, a system is strongly t-diagnosable if it is t-diagnosable and can achieve (t+1)-diagnosability except for the case where a node's neighbours are all faulty. In addition, conditional diagnosability has been widely accepted as a new measure of diagnosability by assuming that any fault-set cannot contain all neighbours of any node in a multiprocessor system. In this paper, we determine the conditional diagnosability and strong diagnosability of an n-dimensional shuffle-cube SQ_n, a variant of hypercube for multiprocessor systems, under the comparison model. We show that the conditional diagnosability of shuffle-cube SQ_n (n=4k+2 and k≥2) is 3n?9, and SQ_n is strongly n-diagnosable under the comparison model.