BNT系纳米粉体的制备及微波特性研究

使用柠檬酸盐法成功制备出分散良好的颗粒状BNT系纳米粉体。经TEM和XRD分析,粉体的平均粒径约30 nm,其主晶相为Nd2Ti2O7,经1 300℃烧结成瓷后还出现了BaNd2Ti4O12相。此类材料具有良好的高频特性,用此类材料研制出的单片微波陶瓷电容器具有良好的微波特性。     

Major Accidents (Gray Swans) Likelihood Modeling Using Accident Precursors and Approximate Reasoning

Compared to the remarkable progress in risk analysis of normal accidents, the risk analysis of major accidents has not been so well‐established, partly due to the complexity of such accidents and partly due to low probabilities involved. The issue of low probabilities normally arises from the scarcity of major accidents’ relevant data since such accidents are few and far between. In this work, knowing that major accidents are frequently preceded by accident precursors, a novel precursor‐based methodology has been developed for likelihood modeling of major accidents in critical infrastructures based on a unique combination of accident precursor data, information theory, and approximate reasoning. For this purpose, we have introduced an innovative application of information analysis to identify the most informative near accident of a major accident. The observed data of the near accident were then used to establish predictive scenarios to foresee the occurrence of the major accident. We verified the methodology using offshore blowouts in the Gulf of Mexico, and then demonstrated its application to dam breaches in the United Sates.     

科技先导驱动是调结构、转方式的战略抉择——厦门科技先导产业发展路径分析

本文阐述了发展科技先导产业的战略意义,总结国内部分先进城市的发展特点,应用SWOT方法分析了科技先导产业的发展形势;从产业发展规律和先导产业的特征出发,以厦门为例提出了科技先导产业重点领域的选择及其发展路径;最后给出了推进先导产业发展的对策建议,为政府制定科技先导产业发展战略提供了决策参考。     

水滑石类复合氧化物的制备及其催化性能研究

采用低饱和共沉淀法制备TMgAL—LDHs、ZnAI—LDHs、CuMgAI—LDHs等几种水滑石结构化合物．研究了pH值和原料比对MgAI—LDHs、ZnAI—LDHs和CuMgAl-LDHs结构的影响．并以这些类水滑石为前驱体得到了MgAI、ZnAI、CuMgAl三种复合氧化物催化剂．研究结果表明：当pH〉9时,对MgAl-LDHs结构的影响较小;当Zn／Al-3时．形成的ZnAl—LDHs结晶度最好;在Cu2＋／Mg2＋=0．25条件下,M2＋／M3＋=2．0时形成的CuMgAl—LDHs结晶度和品形最好;在M2＋／M3＋-3条件下,随着Cu2＋／Mg2＋比的增大．层间距加大．Mg—Al、Zn—A、Cu—Mg—Al三种复合氧化物对逆水煤气变换反应的热稳定性均较好,Cu的引入大幅度的提高催化活性,特别是低温活性的提高尤为明显．     

沉淀反应温度对铜锰复合氧化物结构和催化性能的影响

采用共沉淀法制备铜锰复合氧化物,运用XRD、TPR、BET和常压微反评价装置对所合成样品进行了物相结构和催化性能的研究。XRD分析表明,沉淀反应温度在25~90℃时所合成铜锰复合氧化物前驱体均由Cu2+1O/Mn3O4组成,但随着温度的升高,其晶体组成Cu2+1O/Mn3O4比逐渐提高,晶粒逐渐减小,这些前驱体经550℃焙烧后均转化为Cu1.5Mn1.5O4,且晶粒大小基本相同。TPR分析结果表明,所制备催化剂为单一组成的铜锰复合氧化物,当沉淀反应温度<45℃时,随沉淀反应温度提高样品的还原温度升高,当沉淀反应温度从45℃提高到65℃,还原温度变化不大,只略有下降;而当沉淀反应温度>65℃时,还原温度继续升高。BET结果表明,虽然室温下(25℃)所制催化剂前驱体的比表面积较大,但焙烧后却大幅度下降,反而小于45℃以上样品的比表面积;而当沉淀温度在45℃以上时,焙烧前后样品的比表面积相差不大,样品的比表面积均在36.5-39 m2/g,说明当沉淀温度提高到45℃以上时,焙烧后样品的比表面积与沉淀温度关系不大。沉淀温度45℃是Cu-Mn沉淀物织构发生明显变化的拐点,在此温度下,沉淀反应体系的反应、传递及沉淀物的转...     

期刊原创性选题的功能体现和实施途径

实施原创性选题能充分体现期刊的先导功能、丰富的思想内涵、参与社会生活的能力三大功能;植根于地方性资源,由高素质编审人员去开拓,用延伸服务去争取是三种实施原创性选题的有效方法;编辑素质和论文的发表时滞为两个影响原创性选题实施的因素。     

竹节形碳纳米管的制备和表征

本文采用乙醇催化燃烧法制备竹节形碳纳米管,此方法利用乙醇作为碳源和燃料,提供材料生长所需的能量;利用Cu薄片作为基底;利用FeCl3作为催化剂先体。黑色絮状的沉积物经扫描电子显微镜,透射电子显微镜,拉曼光谱进行表征,发现产物中较细的碳纳米管具有相对较好的竹节形结构,它的隔层是很规则的;然而较粗的碳纳米管的竹节形结构是无规则的,这与催化剂先体的浓度有关。     

清代隶书的复兴及其文化基础

清代隶书的复兴既是书法自身发展的结果 ,又有着广泛深厚的思想文化基础。晚明豪放书风虽然是帖学内部的变革 ,但已在审美思想上开启了清代书学思想转换的思潮。帖学的衰落促使清初的有识之书家进行新的探索 ,因而出现了隶书的复苏 ;文物的大量出土 ,金石考据学的兴起 ,以及在此基础上碑学理论的创立 ,极大地促进了隶书创作的繁荣 ,从而迎来了清代隶书的全面复兴。     

Decision Making During Nuclear Power Plant Incidents—A New Approach to the Evaluation of Precursor Events

Renewed interest in precursor analysis has shown that the evaluation of near misses is an interdisciplinary effort, fundamental within the life of an organization for reducing operational risks and enabling accident prevention. The practice of precursor analysis has been a part of nuclear power plant regulation in the United States for over 25 years. During this time, the models used in the analysis have evolved from simple risk equations to quite complex probabilistic risk assessments. But, one item that has remained constant over this time is that the focus of the analysis has been on modeling the scenario using the risk model (regardless of the model sophistication) and then using the results of the model to determine the severity of the precursor incident. We believe that evaluating precursors in this fashion could be a shortcoming since decision making during the incident is not formally investigated. Consequently, we present the idea for an evaluation procedure that enables one to integrate current practice with the evaluation of decisions made during the precursor event. The methodology borrows from technologies both in the risk analysis and the decision analysis realms. We demonstrate this new methodology via an evaluation of a U.S. precursor incident. Specifically, the course of the incident is represented by the integration of a probabilistic risk assessment model (i.e., the risk analysis tool) with an influence diagram and the corresponding decision tree (i.e., the decision analysis tools). The results and insights from the application of this new methodology are discussed.