某公司汽轮发电机叶片断裂事故分析

某公司汽轮发电机发生汽轮机叶片断裂事故,从宏观检查、材质元素化学分析、材料微观组织、硬度等方面进行分析,找出了叶片断裂原因,并对以后检修提出了建议。     

几种药用植物基因组DNA提取方法研究

采用改良2×CTAB法和改良SDS法提取富含多糖和次生代谢物质的几种药用植物不同器官基因组DNA,并用紫外分光光度计分析,凝胶电泳和PCR扩增进行鉴定。结果表明:改良2×CTAB法和改良SDS法均能有效去除不同药用植物材料中的蛋白质、多糖、酚类及其他次生代谢物质,获得较高质量基因组DNA。但与改良SDS法相比,改良2×CTAB法提取的基因组DNA质量更好。     

Optimal ϵ -stealthy attack in cyber-physical systems

This paper is concerned with the optimal stealthy attack problems of cyber-physical system, which is represented as discrete-time linear systems. It is considered that a deceptive attack assumed to be able to hijack and modify the nominal control signals from the controller-actuator channel with the metric of ? -stealthiness. Different from the existing literatures, some optimal attack strategies with objectives such that maintaining a fixed level of stealthiness and achieving the maximized performance degradation are designed under some constraints. It is further derived that the results of ours are more relaxed than some methods proposed before. Finally, some numerical simulations are given to illustrate the validity of the theoretical results.     

Electrophoretic separation of neurotransmitters on a polystyrene nano-sphere∕polystyrene sulphonate coated poly(dimethylsiloxane) microchannel

In this paper, a poly(dimethylsiloxane) microchip with amperometric detector was developed for the electrophoretic separation and determination of neurotransmitters. For increasing the separation efficiency, the microchannel is modified by polystyrene sulphonate∕polystyrene nano-sphere self-assembly coating. A stable electro-osmotic flow (EOF) and higher separation efficiency are obtained in proposed modified microchannel. Under optimized conditions, dopamine, epinephrine, catechol, and serotonin are acceptably baseline separated in this 3.5 cm length separation channel with the theoretical plate number from 4.6?×?10(4) to 2.1?×?10(5) per meter and resolution from 1.29 to 12.5. The practicability of proposed microchip is validated by the recovery test with cerebrospinal fluid as real sample which resulted from 91.7% to 106.5%.     

Electrophoretic separation of neurotransmitters on a polystyrene nano-sphere�Mpolystyrene sulphonate coated poly(dimethylsiloxane) microchannel

In this paper, a poly(dimethylsiloxane) microchip with amperometric detector was developed for the electrophoretic separation and determination of neurotransmitters. For increasing the separation efficiency, the microchannel is modified by polystyrene sulphonate∕polystyrene nano-sphere self-assembly coating. A stable electro-osmotic flow (EOF) and higher separation efficiency are obtained in proposed modified microchannel. Under optimized conditions, dopamine, epinephrine, catechol, and serotonin are acceptably baseline separated in this 3.5 cm length separation channel with the theoretical plate number from 4.6 × 10⁴ to 2.1 × 10⁵ per meter and resolution from 1.29 to 12.5. The practicability of proposed microchip is validated by the recovery test with cerebrospinal fluid as real sample which resulted from 91.7% to 106.5%.     

Beijing's West District Library Enhances International Cooperation

<正>The West District Library of Beijing is China’s first county/district-level public library granted with the member status of the International Federation of ...     

高职制药校内外生产性实训基地功能定位探析

针对高职制药类专业生产性实训基地建设水平低的现状,分析制药校内外生产性实训基地发展缓慢的原因,提出制药生产性实训基地建设首先要解决功能定位问题;制药类专业生产性实训基地应以药物研发、社会服务为方向,将“药品生产”型实训基地通过深化校企合作建在校外企业。     

任务型教学法在高级英语教学中的应用

以学生为中心的任务型教学法在独立学院高校英语专业教学中的应用日渐普遍。文章以高级英语教学实践为例,重点分析根据任务型教学法的原则和结构模式,合理设计独立学院高级英语课堂教学任务。     

后控规范的计算机处理

分析了建立情报检索系统时受控主题标引的不足之处：标引效率低、语义网得不到扩充、不一致的组配标引。提出了以后控规范为基础的标引体系。为使后控规范能方便地由计算机实现，研究了利用相似性匹配技术找出语义上有一定联系的术语，并由计算机半自动地建立用、代、属、分、参等语义关系的方法。     

Web环境下企业竞争对手情报收集方法分析

随着互联网的发展,基于网络环境下的竞争对手情报的收集显得尤为重要。本文主要介绍了目前比较常用的基于网络环境下的竞争对手情报收集的方法以及强调网络环境下对竞争对手情报的收集的重要性。