Reductive cyclodimerization of arylmethylidenemalononitriles promoted by samarium and catalytic amount of iodine:facile synthesis of cyclopentene derivanves

Samarium and a catalytic amount of iodine were used to obtain functionalized cyclopentenes by reductive dimerization followed by intramolecular cyclization of 1,1-dicyanoalkenes under mild conditions.     

Review: Perspectives on the metallic interconnects for solid oxide fuel cells

The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs) over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coati     

秩序的标记与事件无关--论李洱小说的叙述时间

李洱是一个对细节极为敏感的作家，对细节的张扬造就了李洱小说独特的时间景观。论文通过文本细读，从不需要向故事时间复原的碎片时间、叙述时间上强烈的节奏感以及文本所呈现出来的涡卷图案的叙述线条三个方面，论证了时间在李洱小说中所具有的修辞意义。     

Students' Visualization of Metallic Bonding and the Malleability of Metals

This study investigated the mental representations of metallic bonding and the malleability of metals held by three male students aged 14–15 (Year 10) who were attending a Hong Kong school. One student was selected by their chemistry teacher as representing each of the highest, the medium, and the lowest level of attainment in chemistry in a school that admitted students of average general attainment. The students were interviewed and their understandings probed through their provision of drawings and their interpretation of the diagrams that had been previously used by their teacher. Dual coding theory was used to interpret the relative significance of visual and verbal input and the interaction between the two for their understanding. There was evidence that students relied on verbal recall in providing their initial understandings and showed an appreciation of the nature of the structural components of the electron-sea model of metallic bonding. However, they varied in terms of their appreciation of the electrostatic force which was responsible for the malleability of metals. The study suggests that a clearer understanding of the electrostatic force involved can be attained when students experience visual and verbal representations simultaneously, a conclusion supported by dual coding theory. Principles for good practice in using diagrams in teaching are discussed.     

THE MISCONCEPTION OF ONLINE COMMENT THREADS

Web 2.0 has opened the gates to journalism for online audiences which increasingly participate in the production, dissemination and response processes of news. Comment threads in particular have grown exponentially in recent years as readers have embraced the opportunity to bypass the Letters' Editor and publish their opinions directly to a newspaper website. This rise in participatory journalism has led to new challenges for journalists as they have strived to negotiate the often murky waters of user-generated content. To date, research in this field has been mostly limited to national and international news websites despite local news providers having a close connection and engagement with their communities. This paper therefore seeks to fill this gap partially by analysing the content of comment threads on two British local newspaper websites via a content analysis, while also exploring the experiences of journalists via news room observation and interviews. A contradictory picture emerges whereby journalists accept with some reluctance that comment threads possess a democratic function but one which is potentially damaging to the brand as well as resource intensive. This is juxtaposed by more positive findings that reveal buoyant levels of interactivity between readers in comment threads together with a thirst for engagement in public affairs.     

基于JSP的跨库检索技术的研究开发

针对用户如何同时对多个数据库进行检索的问题，本文讨论了JSP技术同其它几种技术比较所具有的优点，同时也介绍了系统开发所选择的模型和原理以及Java的多线程技术。     

金属晶体结合能的计算

基于失屏参数，建立了一个计算金属晶体结合能的新方法，其计算值与文献值符合得很好。     

Perspectives on the metallic interconnects for solid oxide fuel cells

The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs) over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000 ℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coating materials and techniques may play a key role in pro moting the commercialization of SOFC stack whose interconnects are constructed of some current commercially available alloys. Alternatively, development of new metallic materials that are capable of forming stable oxide scales with sluggish growth rate and sufficient electrical conductivity is called for.     

Surface Investigation of Metal Threads and Solid Metals of Ottoman Textiles in the Topkapi Palace Museum

ABSTRACT

We analyzed 53 historical textile samples from a collection of caftans and brocades dating between the sixteenth and nineteenth century in the Topkapi Palace Museum (TPM) by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Data were collected on the type, dimensions, elemental composition, and level of corrosion. The technique is presented in this work as an efficient and micro-destructive tool for the characterization of the structure of historical metal threads. SEM-EDX analysis for different energies was performed on a selection of gold and silver threads belonging to the historical textiles. The results were interpreted via laboratory prepared samples of gilt Ag and sulfur reacted Ag at different thicknesses for Au and Ag₂S layers respectively. A series of Au–Ag alloys for different Au/Ag ratios were prepared for comparative analysis. The threads were made of metal strips wound around a silk core. Metal wires and flat strips were also used. The use of differential energies allowed for differentiating strips and wires made of homogeneous silver and gold alloys from the ones coated with a thin gold layer. Analysis of EDX data revealed that the Au film thickness was very thin (10–60?nm). Formation of Ag₂S layers over the thin Au film as thick as 1.5?µm was taking place. Formation of thinner Ag₂S layers over non-gilt Ag suggested different reaction mechanisms for gilt and non-gilt cases.     

分布式操作系统中线程包实现方法的对比研究

内核级线程是微内核操作系统的基本调度单位,较好地支持了细粒度的并行计算,但在支持用户分布式并发模型上还有许多缺点,而用户级线程是在核心线程的支持下建立的更高层次的用户级调度单位,能较好地支持用户程序的并发执行。文章重点分析了分布式操作系统中线程包的两种实现方法,并对比研究了它们的优缺点。