东风4C超薄管板换热器的失效分析与改进

对东风C4超薄管板换热器失效形式进行了分析，冷却管组自重变形、空气压力、冷管组自重引起的剪力和挤压应力、银磷铜钎焊的连接强度和振动是主要原因。在设计除了考虑拉脱强度、剪力、挤压力、焊接应力外，还应考虑振动的因素，管板与冷却管的连接改为锡钎焊，管组增加支撑，严格控制焊接工艺，δ取计算中的较大值。     

某一循环流化床锅炉Ⅱ级过热器管材失效分析

利用金相显微镜、扫描电镜（SEM）和定量光谱仪等对465t／h循环流化床（CFB）锅炉Ⅱ级过热器管爆口进行了金相组织分析、宏观及微观形貌观察、材质化学成分以及结构和运行状况分析，探讨了过热器管材的失效原因和机理。结果表明，CFB锅炉内颗粒的冲刷与撞击造成过热器管屏的磨损，磨损引起的壁厚减薄是管材失效的主要原因，磨损机理主要是冲刷磨损和高温腐蚀相结合的冲蚀磨损；管子内压应力与管系应力加速了爆漏过程，是造成过热器管撕裂爆口的次要原因。     

Influence of Damage Evolution on the Failure Surface of Concrete

0 IntroductionTihse a f agilruardeu aolf pcroonccerseste wshuibcjhec itsed ditfofe ernenvitr ofrnommentthale afcatiilounrespatternin general strengthtest .The change of material statescaused by the damage evolution will affect the concretestrengthin a certain kind of concrete.For years ,domestic studies have focused on the effect ofabominable environmental factors on mechanical property ofconcrete,and have resulted in some achievements[1-12]. Thestudies of some current research results reveal …     

轧机主传动轴断裂事故分析

为分析某热轧厂R2轧机传动轴断裂的原因,对该轧机在典型工况下传动轴受力状况进行了现场试验研究,采用现代设计方法对传动轴进行分析,结果表明,平衡力产生的弯矩造成轴的应力集中而导致断裂。根据此结果对轴的结构进行了改进。     

水蛭地龙注射液合大黄粉治疗慢性肾衰的临床观察

通过60例患者在常规治疗基础上加用水蛭地龙注射液的治疗，结果表明治疗纽优于对照组。结论：水蛭地龙注射液与大黄粉合用，即加强了尿毒物质从肠道排出，抑制了肾小管萎缩和纤维组织增生，明显改善了患者慢性肾衰竭症状，延迟了进入透析时间。     

广义系统具有完整性圆盘极点配置控制器设计

考虑线性连续广义系统具有完整性的圆盘极点配置设计问题·利用广义李亚普诺夫方程和不等式给出系统正则、无脉冲,以及极点在圆盘内的充分必要条件·同时针对执行器失效的线性连续广义系统,利用Riccati不等式给出具有执行器完整性圆盘极点配置控制器的设计方法,所设计的状态反馈控制器在系统正常时是正则、无脉冲、极点配置在圆盘内即系统是D允许的,在一定条件下,仍能使执行器故障具有D允许性     

航空蓄电池贮存可靠性分析与失效预防对策

根据航空蓄电池的贮存可靠性特征，对影响蓄电池可靠性的因素进行了系统的分析，提出了蓄电池失效和预防和提高其贮存可靠性的有效方法，对延长航空蓄电池贮存寿命有一定的实用价值。     

冲切破坏理论在浅埋溶洞顶板的利用探讨

研究冲切破坏理论在浅埋溶洞顶板的利用，对已有的经验和理论公式进行完善和修正，使得在基础设计和地勘工作中对溶洞顶板的取舍和利用程度的判断更为准确客观。     

Reliable grading robust stabilization for uncertain time-varying systems via dynamic compensator

A new general model for uncertain time-varying parameters and a new measure sensor failure model are presented, and the problems of both grading robust stabilization and reliable grading robust stabilization for such systems are studied. By the Lyapunov stability theory and matrix algebra method, some sufficient criteria for the above two control problems are established in quasi-linear matrix inequalities (Q-LMIS) forms. In view of linear matrix inequality (LMI) approach, a solving procedure for the Q-LMIS problem is proposed. The solvability of the Q-LMIS problem can be improved obviously by adding some LMI constraints to the Q-LMIS. Based on the two Q-LMIS criteria, a grading robust stable control strategy, namely, the controller with different energy is acted on the system with different uncertain parameter range, is presented. The numerical simulating results show that the grading robust stable control strategy for the robust stabilization of uncertain systems has important theoretical and practical significance.     

矿井煤岩体变形失稳问题的研究

本文对矿井中几种变形失稳现象:煤体冲击地压、矿震、顶底板冲击地压及煤与瓦斯突出,分别建立了煤岩体压缩、剪切、拉伸、固液耦合失稳模型及失稳判别准则,初步构画了矿井煤岩体失稳问题的框架.