[Bmim]BF4离子液体中微波辅助制备TiO2催化剂及活性研究

采用微波加热合成离子液体[Bmim]BF4,以该离子液体为反应介质,在微波辐射条件下制备TiO2光催化剂,在高压汞灯下用甲基橙溶液测试其光催化降解性能;并用XRD,IR,TG对其进行测试和表征。结果表明,制备TiO2光催化剂的较佳条件是:离子液体2.0mL,微波辐射功率600W、反应温度70℃、反应时间35min。并且用[Bmim]BF4作为反应介质,能够显著提高TiO2的光催化活性,所制备的TiO2不需要经过高温煅烧,就表现出极高的光催化活性。该催化剂对甲基橙的降解率在1.5h就可达到93.7%。     

国外语义网发展概述

通过查阅相关文献及调研WWW.ISWC有关语义网的国际会议,从相关标准、语义网工具、研究项目三个方面分别概述国外自2001年以来有关语义网的研究进展,揭示并简要分析目前语义网研究存在的问题及所面临的挑战,为国内语义网的开发提供一些借鉴。     

A comparison of sentence-learning errors in children of different achievement levels

Theoretical analyses of the multiple-choice test format suggest that a test constructor should give serious consideration to the form in which correct and incorrect alternatives are presented. In this experiment, third and fourth graders were tested for previously exposed information by multiple-choice items in which: (a) correct alternatives were stated in either verbatim or synonym form; and (b) incorrect alternatives consisted of plausible responses that were either familiar or new. Comparisons of errors and error patterns were made between high and low achieving students who had been given one of two different information-processing strategies. Based on a dual test function argument, it was concluded that synonym correct alternatives combined with plausible new responses are the most desirable of the four multiple-choice variations studied here. In particular, such items were sensitive to achievement level and strategy differences without systematically increasing students' likelihood of retaining misinformation.     

Incompatible Rhetorical Expectations: Julia W. Carpenter's Medical Society Papers, 1895–1899

This article examines 3 papers presented before the Cincinnati Academy of Medicine by 19th-century physician Julia W. Carpenter. The article identifies 3 strategies Carpenter used to negotiate the incompatible rhetorical expectations for women and for physicians. The published records of academy discussions provide evidence for Carpenter's colleagues' reactions to each strategy, revealing the complexity of her rhetorical situation and demonstrating the complex links among rhetorical practice, professional identity, and a communicator's social position.     

基础教育应对WTO的思考

随着我国加入WTO,各行各业将面临着诸多的机遇和挑战,作为社会发展重要标志的基础教育也不例外。WTO对我国基础教育的影响是深远的,同时,这种影响对基础教育的发展和完善又是一种极好的机遇,只有抓住机遇采取有效的策略,才能使我国的基础教育得到更进一步的发展。     

The accessibility of Chinese local government Web sites: An exploratory study

With the rapid development of Chinese e-government, Chinese citizens are encouraged to access e-government services as their convenience. However, the accessibility of Chinese e-government Web sites has been overlooked. This research study tries to provide an overview of the accessibility of Chinese local government Web sites. Three hundred twenty-four Chinese local government Web sites were examined to find out how accessible they are with reference to the Web Content Accessibility Guidelines 1.0 (WCAG) published by the World Wide Web Consortium (W3C). This research found that all the surveyed Chinese e-government Web sites failed one or more W3C's accessibility measures and thus many disabled Chinese people may have substantial problems to access them. Several valuable recommendations are made based on the research findings and the China's actual conditions.     

3Cr2W8V模具钢球化退火工艺研究

分析模具凹模坯料用冷冲压制造型腔时开裂的原因,进行了几种3Cr2W8V模具钢球热处理软化工艺试验,观察了组织,测定了力学性能,获得实际生产中可行的3Cr2W8V模具钢球化退火工艺．     

通过串音预测对PCB布线的3W规则进行验证

在传输线理论的基础上,利用有限元(FEM)法计算分层介质中微带线上场的分布,并通过SPICE仿真对其等效电路在不同频率电源激励下产生的串音进行预测．预测结果验证了印制电路板布线遵从“3W”规则的重要性．由此得出结论：3W规则的使用有功于PCB设计满足EMC系统设计标准,并最大限度地减小印制线之间的耦合．     

钼表面（Mo,W）Si2-Si3N4复合涂层的低温氧化行为研究

采用包渗法在钼表面原位制备了（Mo,W）Si2-Si3N4复合涂层,考察了其在大气中于500℃和600℃等温循环的氧化性能,利用XRD和SEM等研究了其组织形貌.结果表明：（Mo,W） Si2-Si3N4涂层具有良好的低温抗氧化性,其在空气中500℃和600℃氧化480 h的氧化速率分别为0.0145 g/（m2·h）和0.0191g/ （m2·h）,归因于涂层氧化表面形成了致密的SiO2膜.     

关于行将到来的美国对伊拉克战争

“9·1 1”事件发生后 ,美国政府就强烈倾向在取得阿富汗战争胜利后进入反恐战争“第二阶段” ,而这个阶段被设想和规划的首要内容 ,便是实现解除伊拉克武装和变更伊拉克政权。在布什的心目中 ,发动这场战争关系到美国的眼前和长远安全 ,关系到美国的世界霸权或准霸权地位 ,外加其他一些地缘政治、地缘战略和地缘经济目的以及布什本人的国内政治利益。然而 ,美国无法解决阿拉伯世界的深层问题