Performance evaluation on a double‐layered satellite network

How to evaluate the performance of satellite networks is a prerequisite to the construction of satellite networks, and is also one of challenges in the researches on satellite networks. In this paper, generalized stochastic Petri net (GSPN) models are presented to carry out the performance analysis of a double‐layered satellite network. Firstly, the GSPN model of a double‐layered satellite network is simplified by proper analysis. Then, two sets of experiments are conducted to analyse the performance of the satellite networks, and show that the double‐layered satellite network outperforms single‐layered ones on the heavy traffic load. Finally, the feasibility and effectiveness of the proposed approach is verified by simulation experiments. Copyright © 2005 John Wiley & Sons, Ltd.     

钻井井架力学性能分析

钻井井架作为钻机系统设备中的关键部分,其力学性能直接关系到整套钻机系统的安全生产。文章推导了常用于分析钻井井架力学性能的理论,即线性屈曲、几何非线性和双重非线性理论。提出同时用这三种理论对钻井井架进行综合比较分析,从而合理地预见井架力学性能的方法。以A形钻井井架为例,进行了详细的分析,得到了井架的失稳形式、极限承载、破坏特征及薄弱部位,为钻井井架的设计、优化与评定提供了参考。     

双工频感应加热淬火技术在小型冷轧工作辊上的应用

双工频感应加热淬火Φ200mm以下的小型冷轧工作辊，其性能优于单工频感应加热淬火，延长了轧辊的使用寿命。     

Race as a moderator in a model of sexual harassment: An empirical test.

L. F. Fitzgerald, C. L. Hulin. and F. Drasgow (1995) proposed that victim characteristics, such as race, might moderate the relationships between sexual harassment and its job, psychological, and health status outcomes. This study describes 2 theoretical positions, tokenism and double jeopardy, that could account for this possible moderation by race, as well as the alternative view that no moderating effects exist. The effects of race are empirically examined through simultaneous path analysis. Results indicate that whereas, mean levels of harassment differ across race, the phenomenon of sexual harassment unfolds similarly across races; race is not a moderator of the relationships between sexual harassment and the variables proposed as its antecedents and outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

电话防盗报警器

详细介绍了电话通讯技术以及安全报警技术的应用，二者如何有效地结合起来形成综合联网报警系统。分析了HT9200A和MT8870DC的电路结构，及与AT89C51的接口电路。     

潮州供水枢纽拦河闸计算机监控及运行调度

介绍了潮州供水枢纽工程的概况及拦河闸计算机监控系统的结构和主要功能，着重讨论了闸门的控制过程和自动运行调度，可供其他闸门工程的自动化建设参考。     

Minimizing the number of tool switches on a flexible machine

This article analyzes a tool switching problem arising in certain flexible manufacturing environments. A batch of jobs have to be successively processed on a single flexible machine. Each job requires a subset of tools, which have to be placed in the tool magazine of the machine before the job can be processed. The tool magazine has a limited capacity, and, in general, the number of tools needed to produce all the jobs exceeds this capacity. Hence, it is sometimes necessary to change tools between two jobs in a sequence. The problem is then to determine a job sequence and an associated sequence of loadings for the tool magazine, such that the total number of tool switches is minimized. This problem has been previously considered by several authors; it is here revisited, both from a theoretical and from a computational viewpoint. Basic results concerning the computational complexity of the problem are established. Several heuristics are proposed for its solution, and their performance is computationally assessed.     

二流量试井工艺及资料解释分析方法

描述了二流量试井工艺的实现，从常规分析和双对数曲线拟合两上方面，给出了二流量试井的资料解释分析方法，分析认为二流量试井同样可以计算出正常关井测压力恢复（或压力降落）资料所解释的油藏及流体参数。这种试井方法不但可以减少因正常关井测压对产油量和注水量的影响，而且可以减缓因突然关、开井造成的套管变形或损坏。实践证明，该试井技术方法具有较好的经济效益和应用前景。     

Heterogeneous Enzyme Mimics Based on Zeolites and Layered Hydroxides

Careful combination of a metal compound,a ligand and an inorganic support material leads to supramolecular catalysts that mimic the structural, organizational and functional aspects of enzyme activity.After discussing essential features of metalloenzyme-catalyzed reactions and coordination chemistry in inorganic hosts, we present examples of supramolecular materials selected from our own work that eventually resulted in useful catalysts for organic transformations in the liquid phase.