基于Oracle9i的中国煤炭特性数据库的设计与开发

中国煤炭特性数据库的开发是搭建我国煤炭资源科学研究基础条件平台的基础性工作之一。其目的是有效地集成基础数据、实现资源整合和共享。以利于全面掌握我国煤炭资源特性的基本状况。为制定煤炭资源规划、开发和利用方案提供科学依据。从中国煤特性数据共享需求出发，设计了数据库系统的结构和功能，讨论了Oracle9i在中国煤炭特性数据库开发过程中的应用，着重研究了大型网络数据库的安全管理问题。     

油田水离子色谱分析技术及其在油田开发中的应用

针对常规化学分析方法分析油田水中常量离子的缺点,开展了油田水离子色谱分析技术研究,并应用到泌阳凹陷安棚油田的油田水分析中,为油田开发提供了可靠的分析数据。研究成果表明安棚油田储层条件较差,不同层位油田水受储层性质的影响较大,注入水对储层的溶蚀作用较强。安棚油田浅中层与深层的油田水差别显著,深层油田水受注水的影响更大。泌185—安2108—安65—安27—安2029—泌185等井组成的闭合区域为统一储集体,具有较好油气储集条件。油田水离子色谱分析技术对研究储层连通性、注水开发效果具有重要意义。     

Pro/E2000i环境下基于参数化典型零件库的造型系统

从提高产品的设计效率和质量出发 ,介绍了在 Pro/ E2 0 0 0 i环境下 ,建立参数化典型零件库并利用该零件库实现产品自动化造型的方法及关键技术。同时 ,引入变形设计的思想 ,使该系统在自动化造型的同时 ,实现基于典型零件的变形设计功能     

High-temperature electron backscatter diffraction and scanning electron microscopy imaging techniques: in-situ investigations of dynamic processes

In-situ heating experiments have been conducted at temperatures of approximately 1200 K utilising a new design of scanning electron microscope, the CamScan X500. The X500 has been designed to optimise the potential for electron backscatter diffraction (EBSD) analysis with concomitant in-situ heating experimentation. Features of the new design include an inclined field emission gun (FEG) column, which affords the EBSD geometrical requirement of a high (typically 160 degrees) angle between the incoming electron beam and specimen surface, but avoids complications in heating-stage design and operation by maintaining it in a horizontal orientation. Our studies have found that secondary electron and orientation contrast imaging has been possible for a variety of specimen materials up to a temperature of at least 900 degrees C, without significant degradation of imaging quality. Electron backscatter diffraction patterns have been acquired at temperatures of at least 900 degrees C and are of sufficient quality to allow automated data collection. Automated EBSD maps have been produced at temperatures between 200 degrees C and 700 degrees C in aluminium, brass, nickel, steel, quartz, and calcite, and even at temperatures >890 degrees C in pure titanium. The combination of scanning electron microscope imaging techniques and EBSD analysis with high-temperature in-situ experiments is a powerful tool for the observation of dynamic crystallographic and microstructural processes in metals, semiconductor materials, and ceramics.     

An Optimal Deadlock Prevention Policy for Flexible Manufacturing Systems Using Petri Net Models with Resources and the Theory of Regions

In this paper, an optimal deadlock prevention policy for flexible manufacturing systems (FMSs) is proposed. In an FMS, dead-locks can arise because of a limited number of shared resources, i.e. machines, robots, buffers, fixtures etc. Deadlock is a highly undesirable situation, where each of a set of two or more jobs keeps waiting indefinitely for the other jobs in the set to release resources. The proposed optimal deadlock prevention policy is based on the use of reachability graph analysis of a Petri net model (PNM) of a given FMS and the synthesis of a set of new net elements, namely places with initial marking and related arcs, to be added to the PNM, using the theory of regions, which is a formal synthesis technique toderive Petri nets from automaton-based models. The policy proposed is optimal in the sense that it allows the maximal use of resources in the system according to the production requirements. Two examples are provided for illustration. RID=" ID=" <E5>Correspondence and offprint requests to</E5>: M. Uzam, Ni&gbreve;de &Uuml;niversitesi, M&uuml;hendislik-Mimarlik Fak&uuml;ltesi, Elektrik-Elektronik M&uuml;hendisli&gbreve;i B&ouml;l&uuml;m&uuml;, Kamp&uuml;s, 51100, Ni&gbreve;de, Turkey. E-mail: murat_uzam&commat;hotmail.com     

IEEE 802.11i基于Kerberos架构认证的形式化分析

形式化方法对安全协议的分析有着无可替代的优势,串空间模型又是众多形式化方法中有良好扩展性的方法之一。利用串空间模型对IEEE 802.11i的认证方式中基于Kerberos架构认证进行了机密性和认证性证明,并得出其安全性可靠的结论。最后也提出了形式化方法的不足之处和未来研究方向。     

采用PCE500实现测斜观测现场记录电子化

测斜仪是岩土工程变形监测中的一种十分有效的现测仪器，由于该仪器观测数据量极大，现场观测记录中对采集数据的处理工作相当繁琐，往往制约着该仪器观测精度和观测资料可靠性的提高。如何采用新的方法减轻现场观测的工作量，确保所采集的观测资料精确可靠，具有相当大的实际意义和价值。文章提出一种已在该工程取得较好效果的电子化记录方法，可供参考借鉴。     

DCS500变流装置编码器测速通道的一种特殊应用

通过对DCS500B变流装置的特殊应用和软件编程，简化了卷取机卷径计算的硬件配置，取得了良好的现场使用效果，对于采用多电机进行开卷、卷取的应用场合具有一定实用价值。     

葛一南直流输电系统单极运行对宜昌电网影响情况的分析

介绍了几次葛一南直流输电系统单极运行时葛州坝换流站接地极对近区220kV运行变压器的影响情况，分析了这种影响的电气原理和各次的特点，指出其危害性。