纳米材料在汽车尾气净化中的应用

针对汽车尾气排放及净化现状，阐述了纳米Al2O3载体、纳米贱金属催化剂、纳米稀土催化剂、纳米贵金属催化剂的特性及其在汽车尾气净化催化器中的应用，探讨了纳米材料在汽车尾气净化催化器中的应用趋势．     

汽车尾气净化催化剂的发展及展望

本文介绍了汽车尾气催化净化的发展简史,概述了三效催化剂的组成及作用原理,分析了汽车尾气催化剂发展热点。     

全Pd三效天然气汽车尾气净化催化剂的研究现状

针对汽车尾气所造成的环境污染问题,分析了开发和应用天然气汽车尾气净化催化剂的必要性。阐述了全Pd天然气尾气净化催化剂的发展、现状和展望,分析了各阶段催化剂的特点和性能,讨论了全Pd天然气汽车尾气净化催化剂的可行性和未来研究的方向。     

汽车尾气净化催化剂的研究现状

综述了汽车尾气净化催化剂的组分及其制备的研究现状和进展,展望了汽车尾气净化催化剂的发展前景.     

汽车尾气净化催化剂的发展及展望

本文介绍了汽车尾气催化净化的发展简史，概述了三效催化剂的组成及作用原理，分析了汽车尾气催化剂发展热点。     

Zr掺杂CeO_2体系的电子结构与催化特性的第一性原理研究

目前,用于净化汽车废气的主要材料是三元催化剂(TWC),它可以同时去除汽车尾气中的CO, 碳氢化合物(CH)和氮氧化合物(NOx)这3种主要的有害气体.为了对汽车尾气进行更彻底地净化,寻找高活性和高稳定性的三元催化剂已成为近年来国内外研究的热点.     

汽车尾气净化催化剂的研究及其进展

综述了目前国际上催化消除汽车尾气催化剂的研究现状,分析了三效贵金属催化剂、钙钛矿氧化物催化剂、分子筛催化剂各自的优势和存在的问题。对催化消除机理作了简单的概述,最后对汽车尾气净化催化剂的发展方向提出了展望。     

浅谈汽车尾气的净化

汽车在人们的生活中扮演着非常重要的角色,给人们带来了诸多的方便,但汽车的排放污染物给大气环境造成了严重的污染。因此汽车尾气的净化处理自然也成了社会关注的焦点,寻找研发新的更可行的净化技术无疑是目前最迫切的要求。介绍了汽车尾气的有害成分,说明了汽车尾气的净化处理技术,重点说明一种新型的净化技术——三效催化剂技术,并探讨未来的一个重要发展方向即稀土催化剂。     

汽车尾气处理技术及展望

随着城市步入汽车时代,汽车尾气污染已成为城市乃至全球的一大公害。净化处理汽车尾气是人类社会健康发展之必然,催化剂是当前控制汽车尾气的主要手段。本文介绍了汽车尾气净化剂的发展过程、净化应用、组成原理、制备工艺以及表征评价方法等。     

不同浓度Pt掺杂CeO2储氧材料的第一性原理研究

随着汽车业的高速发展,汽车尾气污染已引起社会的广泛关注。高性能稀土储氧材料CeO2是汽车尾气净化催化剂的关键材料,决定着催化剂的性能和寿命,是各国在汽车尾气净化催化剂领域竞争的焦点。用基于密度泛函理论的第一性原理方法,考虑CeO24 f电子的在位库仑作用,计算并分析了不同浓度金属Pt掺杂对二氧化铈原子结构、电子结构和化学特性的影响。     

Analysis of porcine MHC expression profile

The porcine major histocompatibility complex (MHC, also named swine leukocyte antigen, SLA) is associated not only with immune responsibility and disease susceptibility, but also with some reproductive and productive traits such as growth rate and carcass composition. As yet systematical research on SLA expression profile is not reported. In order to illustrate SLA expression comprehensively and deepen our understanding of its function, we outlined the expression profile of SLA in 51 tissues of Landrace by analyzing a large amount of ESTs produced by ““Sino-Danish Porcine Genome Project““. In addition, we also compared the expression profile of SLA in several tissues from different development stages and from another breed (Erhualian). The result shows: (i) classical SLA genes are highly expressed in immune tissues and middle part of intestine; (ii) although SLA-3 is an SLA la gene, its expression abundance and pattern are quite different from those of the other two SLA la genes. The same phenomenon is seen in HLA-C expression, suggesting that the two genes may function similarly and undergo convergent evolution; (iii) except in jejunum, the antigen presenting genes are more highly expressed in breed Erhualian than in Landrace. The difference might associate with the higher resistance to bad conditions (including pathogens) of Erhualian and higher growth rates of Landrace.     

Selmer groups and Mordell-Weil groups of two types of elliptic curves

Let £: y² = x(x ± p)(x ± q) be two types of elliptic curves, where p and q are twin prime num- bers. The Selmer groups, the sum of rank(E) and dimension of Shafarevich-Tate group (2-torsion subgroup) of E are determined, and the Mordell-Weil group and Shafarevich-Tate group of E are exhibited explicitly in many cases. Besides, the Kodaira symbol and the torsion parts of E are also obtained.     

汉语表现声音的方法举隅

我们生活的这个世界,声音纷繁复杂,而汉语的音节又很有限,以下几种是用汉语语音形式表现声响的常见方法:一、 用象声词表现,若无恰当的象声词时借用同音词替代;二、直接用一个动词来说明或描述,该动词一般是“叫”、“喊”的同义词; 三、在名词或动词后加“声”,为了使其声曼具体,前面可加形容词或象声词等修饰语进行描绘;四、借用比喻、移觉等修辞手法 来体现。     

Synthesis and properties of crown ether benzotellurazole heterocyclic styryl cyanines and merocyanines

Two Crown ether benzotellurastyryl cyanines and three crown ether benzotelluramerocyanines are synthesized via the key intermediate-3-methyl-5,6(15-crown-5)-2 (β-acetanilide) vinyl benzotellurazolium iodide. The reactive conditions are discussed. The influence of alkali (-earth) metal ions on the visible absorption spectra of these two types of crown ether cyanines are also studied. Supported by the National Natural Science Foundation of China Ke Weijun: born in 1971, Ph.D.     

关于单形的两个不等式及其应用——关于单形的两篇文章的注记

(1)本文对单形空间角正弦的两个不等式给出了正确的证明;(2)证明了一个有用的不等式;(3)对文[2]中的定理2及定理3,指出了其证明过程中错误之处;(4)对文[1]的定理2.1及由此得到的几个三角等式进行了推广,并给出了更简洁的证明。     

关于顶点子集凝聚度的若干定理(续)

本文引进斥负集点、斥零集点新概念．并利用这些概念研究出顶点子集X 是只有形如NG（ｖ）最小断集的图G的负集的充要条件是：1°X 包含图G中所有度等于K(G)的顶点；2°图G不包含关于X的斥负集点；3°NG(X)中的任意点U， ，K 表示U与X相邻的顶点数，同时指出Y是图G的非特殊零集的充要条件．     

New research progress on the ultrastructure of tectonically deformed coals

The structure of tectonically deformed coals shows some characteristics and regulations on the ultra-scale when influenced by different factors such as temperature, pressure and directional stress. Deformations of the macromolecular structure may induce changes in the nano-scale pore structure, which are very important for gas adsorption and pervasion. The geological impact of different mechanisms of deformation on different types of ultrastructure of tectonically deformed coals is not only of significance as a topic for scientific research, but also in studying environments of metamorphism-deformation at differing metamorphic stages. This research is also very important in studying the accumulation and occurrence conditions of coalbed methane gas, mechanisms of coal and gas outbursts, predictions of coalbed methane resources and dangers of coal and gas outbursts. This paper analyzes current research, within China and other countries, in the ultrastructure of tectonically deformed coals. The research includes (1) structural models of tectonically deformed coals; (2) the relationship between ultrastructure and stress; (3) the structure of tectonically deformed coals and its strain environment. These results are also based on our own experiments including vitirnite reflectance (R_o,max), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR (CP/MAS + TOSS)). We discuss the important effects of the structure of tectonically deformed coals and their physical properties, and then point out some problems concerning the research progress of tectonically deformed coals.     

鱼类免疫因子Prx 1和Prx 2的研究进展

Peroxiredoxin 1(Prx 1)和Peroxiredoxin 2(Prx 2)是脊椎动物中一种保守的免疫因子,在鱼类的非特异性免疫中扮演重要角色,也叫作自然杀伤增强因子(Natural killer enhancing factor,NKEF A/B)。两类蛋白的N端和C端各含有一个活性半胱氨酸位点。Prx 1和Prx 2能清除机体活性氧(ROS)如H2O2,同时还参与鱼体的抗病免疫。本文对鱼类Prx 1和Prx 2的结构、抗氧化机制、生物学功能进行综述性介绍。     

中国的蜥脚类恐龙化石及其层位

文章对中国的蜥脚类恐龙化石及其层位、产地进行了较为系统的总结,划分出５个相关的蜥脚类恐龙动物群：（１）早侏罗世资中龙动物群（ＺｉｚｈｏｎｇｏｓａｕｒｕｓＦａｕｎａ）;（２）中侏罗世蜀龙－峨眉龙动物群（Ｓｈｕｎｏｓａｕｒｕｓ－ＯｍｅｉｓａｕｒｕｓＦａｕｎａ）;（３）晚侏罗世马门溪龙动物群（ＭａｍｅｎｃｈｉｓａｕｒｕｓＦａｕｎａ）;（４）早白垩世亚洲龙动物群（ＡｓｉａｔｏｓａｕｒｕｓＦａｕｎａ）;（５）晚白垩世纳摩盖吐龙动物群（ＮｅｍｅｇｔｏｓａｕｒｕｓＦａｕｎａ）。文章还对中国的蜥脚类恐龙的地理分布特征进行了探讨。     

我国蝙蝠保护研究现状及对策

蝙蝠是世界上分布最广、进化最成功的哺乳动物类群之一,它们在生态系统中具有重要作用。对于节肢动物而言,它们是捕食者;对于某些脊椎动物而言,它们是被捕食者;而且它们还是种子的传播者和花粉的传授者。在一定生态系统是蝙蝠可能起到关键种的作用。我国对蝙蝠的研究与保护现状令人担忧。文中提出了5项主要研究和保护对策：种类编目;栖息地周围自然环境的保护;觅食地以见觅食路线的保护;冬眠区的保护;通过立法和宣传教育促进社全社会对蝙蝠进行保护。