一种保安型磁力传动阀门的结构设计

介绍了保安型磁力传动阀的结构特征、工作原理及其特点。该阀的结构优点突出,是10万吨环氧丙烷装置氯醇化工段的关键设备。在长期的使用过程中,证明保安型磁力传动阀能有效阻止氯气外泄,保护环境不受污染及操作工人的人身安全。

石油化工行业防静电耐油保安型特种测量电缆的研制

介绍了防静电耐油保安型特种测量电缆的应用范围和性能指标,为了保证电缆具有理想的电气性能、机械物理性能、适合于使用特殊要求的特性,通过对组成电缆的材料进行了研究优选、在结构上进行了优化设计。电缆经试验其各项性能都达到了设计的标准要求。

高层建筑电气负荷计算分析

对高层建筑电气负荷计算的研究具有重大的经济意义 ,它能使所选变配电设备得以充分利用 ,降低大厦和电力系统的投资、降低运行费用、节约电能。

Research on Assessment Model of Information System Security Based on Various Security Factors

With the rapid development of network technology, the meaning of layers and attributes in respect of information system security must be extended based on the understanding of the concept of information system security. The layering model (LM) of information system security and the five-attribute model (FAM) based on security factors were put forward to perfect the description and modeling of the information system security framework. An effective framework system of risk calculation and assessment was proposed, which is based on FAM.

Contrastive analysis and crashworthiness optimization of two composite thin-walled structures

For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF.

Trust Model Based on Structured Protection for High Level Security System

In order to ensure the security of information systems, it's essential to make sure that system behaviors are trusted. By analyzing threats that exist in executing procedures, a trust model based on structured protection is proposed. We consider that functional components, system actions and message flows between components are three key factors of information systems. Structured protection requirements on components, connections and action parameters are also provided. Four trusted properties of the model are deducted through formal analysis, and trusted system behavior is defined based on these properties. Furthermore, decision theorem of trusted system behavior is proved. The developed prototype system indicates the model is practical. It is a general theory model built on logic deduction and independent on specific environment and the behaviors of the system designed and implemented following the model are trusted.

Discussion of the problems of environmental protection in the city management

Since the reform and opening up, the construction in all aspects of our country has achieved a rapid development, and especially the development of the industrial construction is also more prominent, so that each big city rapidly moves forward. But in the development at the same time, some of the issues are inevitable. The rapid development of the cities has attracted a large population, and there are more and more large factories, so that there is more and more pollution in the life and production, which brings greater security risks to the human life and health, and let the cities more difficult to manage. So how to solve these problems and make the cities develop better is a problem worth pondering.

A Checklist of Macrofungi in Yaoluoping Nature Reserve,Anhui

Field work to survey and investigate the Anhui Yaoluoping Macrofungi Nature Reserve was undertaken in order to understand and rationally develop macrofungi resources. The results showed that there are, in total, 101 macro-fungal species and varieties, including 59 kinds of edible mushroom, 20 kinds of medicinal mushroom, and 8 kinds of toadstools, grouped according to their economic values. The species belong to 5 classes, 13 orders, 43 families and 67 genera, Another 14 species are unknown fungus food or medicine and remains to be further de- veloped. They are widely distributed in broad-leaved forests, mixed forests, coniferous forests, bamboo forests, wastelands and areas with other vegetation types. Large fungi resources are abundant; some varieties are rare and very valuable to develop. Among those of value are some edible and medicinal mushrooms, anti-cancer sulfur bacteria, morchella, gold equivalent cow bacilli, pine mushrooms, etc. Some species and species resources have still not been fully investigated. These large fungi can be domesticated and cultivated, and have very good commercial development prospects.

如何选购嵌入式DVR产品

面对众多的嵌入式DVR产品和解决方案，用户如何做出正确的选择呢？以下就是一些选购的基本原则以及应注意的典型问题。