Partial molar volumes of l-alanine,dl-serine,dl-threonine,l-histidine,glycine, and glycylglycine in water,NaCl, and DMSO aqueous solutions at T = 298.15 K

The apparent molar volumes of l-alanine, dl-serine, dl-threonine, l-histidine, glycine, and glycylglycine in water and in the aqueous solutions of NaCl and DMSO with various concentrations at T = 298.15 K have been measured by the precise vibrating-tube digital densimeter. The calculated partial molar volumes at infinite dilution have been used to obtain corresponding transfer volumes from water to various solutions. The experimental results show that the standard partial molar volumes of the above amino acids and peptide at the dilute DMSO aqueous solutions are very close to those in water. However, the volumes show several types of variations with the increase of the concentrations of DMSO due to different types of side chain of amino acids, which should be discussed specifically. The NaCl changes considerably the infinite dilution standard partial molar volumes of the above amino acids and peptide in the aqueous solutions. The infinite dilution standard partial molar volumes of the each amino acids and peptide increase with the concentrations of NaCl. The experimental results have been rationalized by a cosphere overlap model.     

Carbonyl allylation of aldehydes catalyzed by a silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex

A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The palladium(0) complex has been found to catalyze the allylation of aldehydes via the formation of π-allylpalladium complexes, using allylic chlorides as allylating agent and SnCl₂ as reducing agent. This polymeric palladium complex can be recovered and reused.     

基于离散小波变换的蛋白质结构、功能与进化关系延时交叉相关分析

基于氨基酸的疏水特性, 将离散小波变换与延时交叉相关分析相结合, 提出了一种分析蛋白质结构、功能和进化关系的新方法——序列小波层次相关法. 以丝氨酸蛋白酶超家族中Trypsin种属为研究对象, 描述了该方法在揭示不同物种的Trypsin蛋白质进化关系中的应用; 以蛋白质酪氨酸磷酸酶、血红蛋白和溶菌酶为例, 采用该方法揭示了蛋白质之间功能与序列的内在关系. 该方法为非参数方法, 具有简单、直观、可视和可操作性强等特点, 且不需要事先知道蛋白质的结构, 仅从蛋白质的氨基酸序列出发即可比较和揭示蛋白质之间的关系.     

裂解酞菁铁和乙烯制备取向碳纳米管阵列

采用热化学气相沉积(TCVD)法裂解酞菁铁(FePc)和乙烯(C2H4)制备出高210 μm的取向碳纳米管阵列(ACNTA). 用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、拉曼光谱和X射线光电子能谱(XPS)对制备的样品进行了表征, 系统研究了反应温度、反应时间、C2H4流量对ACNTA生长的影响. 结果表明, 样品具有高取向性且纯度高. 800 ℃是裂解FePc和C2H4制备ACNTA的最优温度, 催化剂的活性可以保持较长时间(60 min), 通入C2H4促进了ACNTA的快速生长, 最适合流量为50 cm3/min.     

乙炔和甲基二氯硅烷的硅氢加成反应研究：Ⅲ气固相反应规律探讨

比较了铂，铑，钯的氯化物对乙炔和甲基二氯硅烷的气固相硅氢加成反应的催化活性；筛选了铂催化剂中的无机载体；研究了浸渍法和制备的铂催化剂的催化反应行为。结果表明，浸渍法制备的铂催化剂中存在两类稳定性不同的活性中心，铂离子是具有催化活性的组分，甲基二氯硅烷与铂离子间的氧化还原反应是导致催化剂     

Black fungus derived aerogel with double faced properties

Black fungus aerogel (BFA) exhibited interesting double-faced properties. Weexplored the diverse properties of each side of the black fungus in three aspects:water contact angle measurements, liquid selective absorption capacity and air pollutant adsorption abilities.     

Synthesis, structure and fluorescence of a novel diarylethene

The photochromic diarylethene, 1,2-bis(2-methyl-5-(2-(1,3-dithiolpentane))-thien-3-yl)perfluorocyclopentene (BMDTP), has been synthesized in high yield and its structure was determined by X-ray crystallographic analysis. The compound undergoes a photochromic reaction both in solution and in the single crystalline phase. In addition, its fluorescence property in solution is discussed.     

Synthesis of differentially protected ribitol derivatives from 3,4-O-benzylidene-d-ribono-1,5-lactone

Several differentially protected ribitol derivatives were synthesised using 3,4-O-benzylidene-d-ribono-1,5-lactone as versatile starting compounds for oligosaccharide synthesis. The obtained ribitol derivatives allow the regiospecific coupling of glycosyl donors to either of the hydroxyl groups of ribitol and can be applied for the preparation of polyhydroxylated compounds.     

主成分回归-紫外光度法同时测定食用香料麦芽酚和乙基麦芽酚

报道了一种快速、简便的同时测定食用香料麦芽酚、乙基麦芽酚光度法,方法基于在pH2.87的B R缓冲溶液中对麦芽酚和乙基麦芽酚两组分混合溶液进行光度测定,所得的重叠波谱数据用主成分回归法(PCR)、经典最小二乘法(CLS)和偏最小二乘法(PLS)等化学计量学方法进行处理,结果表明主成分回归法(PCR)的预报误差最小。对样品进行测定,获得了较好的定量分析结果。麦芽酚和乙基麦芽酚的线性范围均为1.0～20.0mg·L-1;检出限分别为0.4347和0 5589mg·L-1。     

Oxidative Methyl Esterification of Primary Alcohols with Iodine‐Mediated Poly[4‐(Diacetoxyiodo)Styrene]

An operationally simple oxidative methyl esterification of primary alcohols in good yields using an iodine‐mediated poly[4‐(diacetoxyiodo)styrene] in methanol at room temperature is described. The polymeric reagent can be regenerated and reused as an environmentally benign reagent.