ZrO2在Cu-ZnO-ZrO2甲醇水蒸汽重整制氢催化剂中的作用

通过对一系列Cu-ZnO-ZrO2甲醇水蒸汽重整(SRM)催化剂的XRD、TEM和BET表征及催化性能测定,研究催化剂中ZrO2对催化剂粒径、比表面以及对SRM反应性能的影响.结果表明,ZrO2的加入,使催化剂的粒径从15 nm降至10 nm（其中CuO和ZnO的平均粒径分别从7.7和10.4 nm降至3.9和8.7 nm）,BET比表面从60 m2•g－1增至78 m2•g－1.随着催化剂含ZrO2量不同,甲醇的转化率和H2、CO2的选择性均产生变化,当催化剂中Zr含量为24.0％(w),反应温度为220 ℃,水、醇摩尔比为1.3时,甲醇的转化率达到51.6％, H2和CO2的选择性达到100％(CO和CH4在产物气体中的体积分数小于10－4),这一结果对甲醇燃料电池甲醇重整器的应用具有重要的意义.     

Rearrangement of 5-trimethylsilylthebaine on treatment with L-selectride: an efficient synthesis of (+)-bractazonine

Treatment of 5-trimethylsilylthebaine with L-Selectride gave rise to a rearrangement to 10-trimethylsilylbractazonine through migration of the phenyl group, whereas treatment of thebaine with strong Lewis acids is known to lead to a similar rearrangement through migration of the alkyl bridge to give, after reduction, (+)-neodihydrothebaine. It is suggested that the rearrangement of the alkyl group of thebaine is favored due to the formation of a tertiary benzylic cation. However, for 5-trimethylsilylthebaine, the lithium ion of L-Selectride acts as the Lewis acid and the beta-silyl effect dominates in the stabilization of any positive charge. This rearrangement provides a clear example of the greater relative migratory aptitude of phenyl groups over alkyl groups, and provides an efficient synthesis of (+)-bractazonine from thebaine.     

Characterization and electrochemical investigation of boron-doped mesocarbon microbead anode materials for lithium ion batteries

The structure and anodic performance of boron-doped and undoped mesocarbon microbeads (MCMBs) have been comparatively studied and the results obtained by XPS, XRD, SEM, Raman spectroscopy and electrochemical measurements are discussed. It is found that boron doping introduces a depressed d ₀₀₂ spacing and the larger amount of "unorganized carbon", which induces vacancy formation in the graphite planes and leads to a quite different morphology from that of the undoped material. Electrochemical charge/discharge cycle tests indicated that after boron doping the lithium intercalation was carried through at a somewhat higher potential, being attended by greater irreversible capacity loss. Electronic Publication     

含环氧端基酚酞聚芳醚酮E-PEK的合成及表征

由酚酞和4,4′-二氯二苯酮经亲核缩聚制得了一系列不同分子量的含—OK端基的聚醚酮低聚物,将其与环氧氯丙烷反应得到了分子量为1000～8000的含环氧端基聚芳醚酮(E-PEK)。用IR和~1H NMR表征了E-PEK的分子链结构,测定了T_g、溶解性和熔融粘度。研究了E-PEK/DDE体系的固化,固化后树脂的T_(g∞)=183～215℃,与低聚物的初始分子量有关。     

手性高效液相色谱法测定1—（6‘—甲氧基萘）乙醇不对称氢酯基化反应

在自制的硅基纤维素－三（３，５－二甲基苯基氨基甲酸酯）高效液相色谱手性固定相上（ＨＰＬＣ－ＣＳＰ），优化了１－（６＇－甲氧基萘）乙醇氢酯基化反应产物－萘普生甲酯手性分离的条件，测定了相应的一系列不对称氢酯基化反应产物的对映体过剩值（ｅ．ｅ．值）。结果表明，在ＣＤＭＰＣ－ＣＳＰ手性柱上用ＨＰＬＣ测定此类不对称催化反应的光学产率，评价催化剂体系的手性选择是一种非常理想的方法。     

纳米级金膜微电极的制作,表征及异相催化反应

报道了纳米级金膜微电极的制作方法，用ＸＰＳ及ＳＥＭ对电极表面进行了表征，考察了该电极的循环伏安及计时电流特性，在聚吡咯修饰微带金电极上成功地实现了葡萄糖氧化酶和电子传递媒体Ｆｅ（ＣＮ）６＾３－的同时固定，并研究了ＧＯＤ／Ｆｅ（ＣＮ）６＾３－／ＰＰｙ微酶电极对葡萄糖的响应，稳态响应电流与葡萄糖浓度之间存在Ｍｉｃｈｅａｌｉｓ－Ｍｅｎｔｅｎ动力学特征。     

Combinatorial Synthesis and Multidimensional NMR Spectroscopy: An Approach to Understanding Protein–Ligand Interactions

Combinatorial chemistry is a laboratory emulation of natural recombination and selection processes. Strategies in this developing discipline involve the generation of diverse, molecular libraries through combinatorial synthesis and the selection of compounds that possess a desired property. Such approaches can facilitate the identification of ligands that bind to biological receptors, promoting our chemical understanding of cellular processes. This article illustrates that the coupling of combinatorial synthesis, multidimensional NMR spectroscopy, and biochemical methods has enhanced our understanding of a protein receptor used commonly in signal transduction, the Src Homology 3 (SH3) domain. This novel approach to studying molecular recognition has revealed a set of rules that govern SH3–ligand interactions, allowing models of receptor–ligand complexes to be constructed with only a knowledge of the polypeptide sequences. Combining combinatorial synthesis with structural methods provides a powerful new approach to understanding how proteins bind their ligands in general.     

聚双环戊二烯反应注射成型

本文介绍了国外有关聚双环戊二烯反应注射成型的研究进展，讨论了国内进行聚双环戊二烯反应注射成型开发研究的现实意义，并对这一领域的发展进行了展望     

八—4—(四氢糠氧基)双酞菁衍生物钕(Ⅲ)、铕(Ⅲ)的合成和LB膜的气敏性

八—４—（四氢糠氧基）双酞菁衍生物钕（Ⅲ）、铕（Ⅲ）的合成和ＬＢ膜的气敏性张引＊辛春梅王丹（吉林省教育学院化学系，长春１３００２２）梁冰洁＊＊陈文启席时权（中科院长春应用化学研究所，长春１３００２２）关键词：希土双酞菁衍生物ＬＢ膜气敏性荧光性紫外可见...     

Separation and preconcentration of ultratrace lead in biological organisms and its determination by graphite furnace atomic absorption spectrometry

A biological organism (chitosan) was utilized to preconcentrate lead ions from tap water. This preconcentration was achieved by mixing 0.8 ml of chitosan slurry with 10-50 ml of lead-containing solution and subsequently separating by centrifugation. The chitosan paste was then dissolved in 1 ml of 0.2% nitric acid and analysed by graphite furnace atomic absorption spectrometry. The extraction efficiency can approach 100% in the pH range 4-10. The amount of chitosan used was not critical. The effect of some impurities was also investigated. If six samples were prepared simultaneously, the time needed to preconcentrate each sample was less than 3 min. Two different modes of standard addition (the standard lead solutions being added before and after preconcentration) were used for analysis of tap water samples, and the results obtained by the two modes were found to be quite consistent.