基于NS2的无线网络隐藏节点问题仿真实验

提出用NS2设计一个观测无线网络隐藏节点问题的实验,并介绍了实验开发过程.该实验项目为计算机网络课程的实验教学提出一种新的思路,有助于学生实践能力和创新能力的培养.     

基于J2EE技术的教务处办公系统的研究与实现

通过对清华大学教务处办公管理现状和需求的分析研究,设计并实现了一种整合Struts和Hibernate框架的基于J2EE平台的教务处办公系统,实现了教务处日常行政办公的网络化和数字化,构建了面向处内的日常行政办公与信息交流、面向校内的信息服务、面向校外的宣传窗口三位一体的网络环境和平台.该系统结构清晰、功能丰富、职责明确、界面友好,并具有良好的可扩展性、实用性和可维护性.由于该系统所体现的三位一体的分层思想对其他办公系统具有较强的适用性,因此具有广阔的推广应用价值.     

Photocatalytic Reduction of 6-Chloro-3-Nitrotoluene-4-Sulfonic Acid in Presence of Surfactants

Photocatalytic reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid （CNSA） was studied in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. A mixture of CNSA, TiO2, water, additives and surfac- tants was put into a quartz glass reactor with a jacket, which was irradiated with a high pressure Hg lamp in the purg- ing of nitrogen gas. With methanol, the conversion of CNSA increased from 7.7% to 34.6%. Three surfactants signifi- cantly promoted the photocatalytic reduction conversion in reduced order of sodium dodecylbenzenesulfonate （DBS）, cetyltrimethylammonium bromide （CTAB） and sodium dodecylsulfate （SDS）. In suspensions involving DBS and CTAB respectively, CNSA conversion increased in consistence with the adsorption ratio with methanol, but varied inversely with the adsorption ratio without methanol. But no obvious influence on the adsorption ratio was observed with or without methanol added when the SDS concentration was critical micelle concentration （cmc）. The photocata- lytic reduction of CNSA was enhanced in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. Methanol inhibited the recombination of photogenerated holes and electrons efficiently. Surfactants around 1 cmc led to the highest reduction conversion.     

Influence of Calcination Temperature on TiO2 Nanotubes＇ Catalysis for TiO2/UV/O3 in Landfill Leachate Solution

The influence of calcination temperature on TiO2 nanotubes＇ catalysis for TiO2/UV/03 was investigated. TiO2 nanotubes （TNTs） were prepared via the sol-gel method and calcined at 300--700 ℃, which were labeled as TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700, respectively. TNTs were characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. It is found that TNTs calcined at 400 ℃ showed the best thermal stability. When the calcination temperature increased from 400 ℃ to 700 ℃, the special structure of tubes was destroyed and gradually converted into nanorods and/or particles. The transformation from anatase to rutile occurred at 600 ℃, and the rutile phase was enhanced when the calcination temperature was increased to over 600 ℃. The calcina- tion temperature＇s influence on TNTs＇ adsorption activity for for TiO2/UV/O3 was investigated in landfill leachate solution chemical oxygen demand （COD） and catalytic activity In landfill leachate solution, the adsorption activity of COD decreased in the reduced order of TNTs-300, TNTs-400, TNTs-500, TNTs-600 and TNTs-700. In photocatalytic ozonation, TNTs-400 showed the best catalytic activity while TNTs-700 exhibited the worst. In other three processes, the COD removal of TNTs-300/UV/O3 was higher than those of TNTs-500/UV/O3 and TNTs-600/UV/O3 in the first 20 rain, and then became close to those of the latter two in the following 40 rain. Compared with TNTs-300 and TNTs- 400, TNTs-600 had the best anti-fouling activity, while TNTs-500 and TNTs-700 had lower anti-fouling activity than the former three. In photocatalytic ozonation, the calcination temperature of 400 ℃ was appropriate when TNTs were obtained at the synthesis temperature of 105 ℃.     

基于NS2的Ad Hoc网络路由协议分析实验

介绍了Ad Hoc几种典型的路由协议和NS2,给出了在NS2下进行Ad Hoc网络仿真的方法和步骤,对数据成包发送率、端到端时延及路由负荷参数进行分析比较。     

香菇中麦角甾醇生成维生素D_2的光化反应实验设计

蘑菇中的麦角甾固醇经紫外线照射后可产生维生素D2,能被人体吸收利用,是天然维生素D的重要来源之一。为了增进本科生对脂溶性维生素代谢的认识和理解,设计了从香菇中提取麦角甾醇,再经光化反应将麦角甾醇转化为维生素D2的生物化学教学实验。为简化实验步骤、方便教学,试验筛选出了样品预处理、光反应及热反应的最佳条件,确定了不经皂化处理,提取物先后用254、365 nm的紫外光照射1 h后,置于85℃水浴下处理15 min实验流程。经高效液相色谱分析,测得产物收率为4.5%。     

Erlang（2）风险过程在阈红利策略下的破产概率

研究了阈红利策略的Erlang（2）风险模型的破产问题,即给出了最终破产概率的两个微积分方程,推导出了它的解或更新方程．在索赔额为指数分布条件下计算出了相应的数值结果．     

二语写作的文化导入

写作是一种深嵌入文化的行为,二语写作是书面形式的复杂的跨文化交际活动。对比修辞学为二语写作教学的文化导入提供了理论依据。在二语写作教学的选词、造句、组段、谋篇等指引性程序训练中,文化导入的主要内容为词汇文化、句法文化、语篇文化。语言知识的习得与文化习得同步发展,有助于二语学习者产出地道的、体现其文化精髓的作品。     

高校二级学院校园文化品牌建设探析——以湖州师范学院医学院为例

高校二级学院校园文化品牌建设,对于增强学院内部的凝聚力,实现学院的发展具有重要的意义。二级学院校园文化品牌建设的原则应体现大学精神,体现专业特色,体现传承和发展。而具体建设的途径则应包括提升品牌的价值、丰富品牌的精神内涵、加大品牌的培育力度、重视品牌的仪式功能与意义等。     

数字图书馆虚拟参考咨询系统的设计

在本文中备选开发平台主要是J2EE开发平台和.Net开发平台.在进行深入的调研之后将最终决定使用哪个开发平台来开发满足客户要求的WEB应用程序.