面向高速工业无线网络的TDMA MAC协议设计与实现

随着无线技术的发展,在工业自动化中引入无线技术已经成为一种潮流,同时TDMA机制由于可以完全避免冲突,因此在大规模高实时要求的面向车间的无线技术研究中受到了广泛关注,但现在面向车间的高速实时无线技术的研究大都局限于软件仿真。通过在商用802.11硬件上设计并实现面向车间级工业应用的高速工业无线TDMAMAC层协议,建立了一个基于TDMA的面向工业应用的高速无线网络原型系统,实验结果表明实验平台完全能够支撑毫秒级时隙调度的TDMA应用。     

对MMI质量流量计计量系统通信故障的处理

武汉石油化工厂计量办检测站于１９９５年５月投用了一套用于成品油水路出厂计量的质量流量计微机计量系统,运行两年多,工厂的成品油出厂损耗逐年下降（目前实际出厂损耗率已经控制在１０．１％以内,远远低于±０．３％的国家标准）,用户索赔情况日趋减少,取得了较好的经济效益和社会效益。其后,该系统的通信部分突发故障,计算机无法采集流量计的数据,造成系统停用。我们经过认真检测、分析,终于排除了故障,保证了成品油出厂计量。具体介绍如下,供交流。１系统简介 检测站毗邻我厂的长江码头,进出厂的油品管线均经过此地。按规…     

浅析信息化教育环境下，高校教师如何提高教学质量

随着信息技术教育在高校的深入发展,教学质量受到进一步的关注,该文探讨了在高校信息技术教育背号下,作为教师,应该如何提高教学质量。     

构建基于XML的在线备忘录

XML能够使用得Internet上的数据交换变得更方便,XML与数据库一样,都能够作为信息存储的途径。当数据量不大的时候,比如完成一个在线备忘录,XML作为数据存储具有关系数据库所无法比拟的优势。在asp.net中能够利用.net类库提供的类及方法轻松地构建一个基于XML的在线备忘录。     

CORBA动态测试工具设计

在网络管理系统中CORBA技术被广泛应用在北向接口模块中,在测试这类模块时通常会针对不同的规范开发专门的测试程序,费时费力,且没有通用性。该文介绍了一个基于idl语法分析的动态测试工具,可动态测试不同规范的CORBA接口,大大提高了生产效率。     

Structural-symmetry-related sequence patterns of the proteins of beta-propeller family

It is still not very clear to what extent and how does the amino acid sequences of proteins determine their tertiary structures. In this paper, we report our investigations of the sequence-structure relations of the proteins in the beta-propeller fold family, which adopt highly symmetrical tertiary structures while their sequences appear "random". We analyzed the amino acid sequences by using a similarity matrix plus Pearson correlation method and found that the sequences can show the same symmetries as their tertiary structures only if we deduce the conditions of sequence similarity. This suggests that some key residues may play an important role in the formation of the tertiary structures of these proteins.     

Performance lower bounds in stochastic robust and adaptive control

The fundamental issues of capability of robust and adaptive control in dealing with uncertainty are investigated in stochastic systems. It is revealed that to capture the intrinsic limitations of adaptive control, it is necessary to use sup_t types of transient and persistent performance, rather than lim sup_t types which reflect only asymptotic behavior of a system. For clarity and technical tractability, a simple first-order linear time-varying system is employed as a vehicle to explore performance lower bounds of robust and adaptive control. Optimal performances of nominal, robust and adaptive control are explicitly derived and their implications are discussed in an information framework. An adaptive strategy is scrutinized for its achievable performance bounds. The results indicate that intimate interaction and inherent conflict between identification and control result in a certain performance lower bound which does not approach the nominal performance even when the system varies very slowly. Explicit lower bounds are obtained when disturbances are either normally or uniformly distributed     

低压长袋脉冲袋式除尘器设计与应用

以工业原料尤里卡沥青(EP)为对象，详细论述了低压长袋脉冲袋式除尘器的主要设计环节，着重分析了新型脉冲阀技术。指出了该技术在化肥行业原料干燥、风扫制备等方面的推广应用和发展趋势。     

中药知母有效组分——知母皂甙元“滋阴”作用的研究

本工作以~(123)I-心得静结合分析法及环核苷酸RIA法观察了知母中提取得到的知母皂甙元对甲亢模型(模拟“阴虚”)βAR-cAMP系统的作和,结果表现,知母皂甙元明显降低甲亢小鼠脑β受体的RT值,显著降低甲亢小鼠β受体-cAMP系统的反应性,重现了知母水煎剂的下调作用。体外竞争抑制实验表明,知母皂甙元和知母皂甙元半琥珀酸都不能抑制~(125)I-心得静与β受体的结合。