Research and implementation of cooperative cache for PVFS

At present, there are many effective ways to achieve high performance in cluster system storage management, including server-end disk, server-end caching, local caching and cooperative caching. The cooperative caching mechanism shares caches among different clients so as to avoid expensive disk access costs and to improve overall throughput of cluster system. In this paper, a Single Copy Cooperative Cache model is proposed together with block lookup algorithm, block replacement algorithm and the consistency algorithm based on the model. Meanwhile, the prototype system of the model is implemented in PVFS file system. Finally, the performance of this system is tested in InfiniBand Framework, the result of which shows that in contrast to the original PVFS system, read performance of PVFS file system is improved by about two times, while write performance is reduced by nearly ten percent.     

初始模型的不确定性对梁式结构静力损伤识别的影响

结合初始模型和结构损伤的概率定义,给出了一个具有统计意义的梁式结构静力损伤识别方法.在此基础上,重点研究了初始模型的不确定性对损伤识别的影响.经数值分析,发现当初始模型的不确定程度低于或基本相当于损伤程度时,本文的方法依然具有较好的损伤识别效果.而当初始模型的不确定程度超过结构损伤程度时,已无法识别出结构损伤.因此,为了获得较好的损伤识别结果,必须保证初始模型具有足够的精度.     

中国铁路建设史上的又一座丰碑——宜万铁路(二)

“释能降压”专项技术 “释能降压”技术，就是针对隧道施工中所遇到的高压富水充填溶腔，选择适当的时机，采取有计划、有目的的精确爆破，把溶腔打开，释放溶腔内所存储的高压泥水，削减势能，降低泥水压力，从而消除隧道溶腔处理的高风险。然后。对溶腔进行清淤、     

我国燃气汽车标准体系的现状分析与发展建议

以我国现有的燃气汽车标准体系为研究对象,结合我国燃气汽车产业现状和前景,论述了我国燃气汽车标准体系持续健康发展的现实意义和必要性,本文采用查阅资料、调研走访等相结合的方法,对国内现有燃气汽车标准体系的情况进行归纳,对比国际燃气汽车标准体系,分析我国目前燃气汽车标准体系存在的不足与问题,并提出针对性的发展建议。     

中山磨刀门水域游艇安全管理研究

在充分调研磨刀门水道及附近水域通航环境的基础上,结合游艇的特点和我国其他地区游艇安全方面出现的主要问题和监管的不足,对游艇及其活动水域进行风险分析,并对磨刀门水域游艇安全管理工作提出建议。     

混凝土桥面涂料防水层的标准化施工

桥面钢筋混凝土现有预制的也有现浇的;现有预应力的也有非预应力的。而桥面防水层是设置在混凝土桥面板和沥青混凝土铺装层之间,保证混凝土桥面板整体防水抗渗性能的技术难度较大．为此除了要求防水涂料要有渗透作用弥补细微裂纹,以保证防水层足够的不透水性能外,     

A Hemodynamic Study of the Effect of Neuromuscular Electrical Stimulation on Enhancing Popliteal Venous Flow

Neuromuscular electrical stimulation has been studied to be a method of prophylaxis for deep venous thrombosis by activating the calf muscle pump. However, there is little evidence of the effects of different stimulating parameters on hemodynamics and comfort levels. The objective of this paper is to compare the effects of different stimulating parameters(current amplitude, pulse-width) on hemodynamic alterations of the popliteal vein and the comfort levels in a group of fourteen healthy subjects. Doppler ultrasound detection of peak venous velocity and blood volume were taken from baseline, twelve sequential electrical stimulations and foot dorsiflexion for each subject. A visual analogue scale was used to assess the subjects' pain perception of neuromuscular electrical stimulation. The results showed that peak venous velocity and blood volume augmented as current amplitude and pulse-width increased while pain level also increased. A compromise was reached that parameters consisting of an amplitude of 10 m A and a pulse-width of 500 μs would obtain a high-peak venous velocity and blood flow volume with a relatively comfortable perception. In addition, parameters consisting of an amplitude of 20 m A and a pulse-width of 300 μs were also shown to be a promising choice. However, further studies need to be done to validate and enrich these findings.     

桥梁工程高墩施工技术研究

针对桥梁工程高墩施工,分别在模板施工、混凝土工程施工以及墩身施工监测等几方面详细介绍了桥梁工程薄壁空心高墩施工技术,可以为桥梁工程高墩建设施工项目作业管理提供合理的技术参考。     

交流系统短路电流上升率特性分析及其应用*

论文从船舶交流电力系统短路电流主要馈送来源着手,建立系统模型并对短路电流上升率进行数学公式推导,然后从船舶电力系统角度对决定短路电流上升率的因素进行分析,并讨论了不同短路角时短路电流的变化趋势对电流上升率的影响。通过对比仿真,给出一定船舶电力系统下具体短路点故障诊断时参考电流上升率的选取方法和条件。参考电流上升率的选取方法为船舶电力系统电流上升率作为故障诊断整定设定提供参考。     

张唐铁路（64＋64）m T型刚构设计分析

该文以新建张家口至唐山铁路工程T型刚构为工程背景,介绍（64＋64）m T型刚构的结构特点及设计思路,并着重对T型刚构的桥型优势,梁体钢束布置,转体施工球铰局部效应,曲线T型刚构转动中心计算等进行了详细分析.所得结论可为同类工程的设计提供参考.