Synthesis of a novel sulfur-bearing secondary antioxidant with a high molecular weight and its comparative study on antioxidant behavior in polypropylene with two commercial sulfur-bearing secondary antioxidants having relatively low molecular weight

A novel sulfur-bearing secondary antioxidant with a high molecular weight of 2252 (OS-POSS), successfully synthesized via photoinitiated thiol-ene click reaction, was compared with two commercial sulfur-bearing secondary antioxidants on the stabilization of polypropylene (PP). The results of their oxidation induction time (OIT) via differential scanning calorimeter measurement (DSC) showed that the higher the molecular weight of secondary antioxidant is, the longer the OIT value, whether such sulfur-bearing antioxidant is used singly or in combination with primary antioxidant. The study of their long-term accelerated thermal aging in the air oven at 150 °C displayed that the molecular structure of sulfur-bearing secondary antioxidant, besides molecular weight, is another highly important factor determining the antioxidant efficiency, i.e., physical loss of antioxidants with the relatively low molecular weight may determine antioxidant efficiency, whereas thioether groups having neighboring ester carbonyl moieties may decompose more hydroperoxides with quicker rate.     

纳米孔分析化学

源于自然界,服务于人类社会的纳米尺度装置包括生物及人工制备的纳米孔与纳米通道等。基于这些纳米尺度装置的分析化学简称纳米孔分析化学。本文对纳米孔分析化学的发展,特别是近年来在DNA测序、蛋白质分析的进展进行了综述,对于纳米孔分析化学发展的历史、基本分类、原理和应用作了介绍与展望。     

Third Generation Horseradish Peroxidase Biosensor Based on Self-assembling Carbon Nanotubes to Gold Electrode Surface

Carbon nanotube (CNT) is a novel carbon material discovered by Iijima1. It had beenfound to have the ability to promote electron transfer reactions when it was used tofabricate electrodes for the oxidation of biomolecules2-4. Just recently, the interest indemonstrating CNT for biosensing applications is now emerging5-10. However, most ofthese biosensors were based on CNT paste electrode or CNT modified glassy carbonelectrode by casting technology. Here, we reported another assembly…     

Electrochemical Detection of Clenbuterol in Pig Liver at Pyrrole-DNA Modified Boron-doped Diamond Electrode

Introduction Clenbuterol { 4-amino-[( tert-butylamino) meth-yl]-3,5-dichlorobenzyl alcohol hydrochloride} is aβ-agonist drug[1]. It can improve the ratio of muscle tofat when it is administrated with high doses to ani-mals[2,3]. However, the residues of clenbuterol(CL)are toxic to humans, leading to sickness and possibleheart complication[4]. It has been reported that CL iseasy to accumulate in animal livers.Recently, some analytical methods for the detec-tion of CL, such as HPLC[5], GC…     

Synthesis and Characterization of A Novel Cholesteric Liquid Crystalline Containing Carboxyl Group

A novel liquid crystal compound with a carboxyl group at one end, cholest-5-en-3-ol-(3β) hydrogen decanedioate (1) was successfuly prepared by the reaction of cholesterol with sebacoxl chloride. Its chemical structure and liquid crystalline properties were characterized by FTIR.CNMR,HNMR,POM and DSC. The compound with an active carboxyl group shows themortropic liquid crystalline behaviour.     

Pulse Plating of Zn-Co Alloy Coatings

Pulse plating of Zn-Co alloys was studied using square pulse containing reverse current.The surface morphologies of Zn-Co alloy deposits were examined using scanning elecron microscopy （SEM）, and an attendant energy dispersive X-ray analyzer （EDA） was used to analyze the composition of Zn-Co alloy deposits. Results obtained showed that the average current density and reverse current density amongst all the variables investigated had very strong effects on the cobalt content and surface morphologies of Zn-Co alloy deposits. It is possible to elecrodeposit Zn-Co alloy coatings with a very wide cobalt content range of 10-90 wt% by modulating pulse parameters.     

底质中总磷的测定方法探讨

在一定的温度下,用硫酸和高氯酸进行消解,使不溶性磷酸盐和有机磷转化为正磷酸盐进入溶液,待测液与钼酸铵反应生成磷钼杂多酸,当加入还原剂氯化亚锡后则转变成蓝色络合物,进行比色测定。该法随氧化剂的种类、反应温度和时间,以及中和剂碱的种类不同可获得不同的结果。因此,必须严格按操作步骤进行。测定结果显示,精密度和准确度满足实验要求。     

四氯化锡诱导的Prins环化法高选择性地合成四氢吡喃衍生物合成四氢吡喃衍生物

本文通过预先将醛和四氯化锡进行配位形成高活性的醛中间体,同时采用滴加高烯丙醇的方法高收率和高选择性地合成了2,4,6-三取代四氢吡喃.     

热分解法和碳热还原法制备掺钨VO2 /云母复合粉体的热致变色性能

用溶胶凝胶法和喷雾干燥技术在云母微粉表面包覆了不同nW/nV的掺钨V2O5溶胶,分别采用热分解和碳热还原得到了掺钨VO2/云母复合粉体。通过XRD、SEM对复合粉体进行了物相组成、微观形貌的表征。将复合粉体添加到紫外光固化树脂中形成复合薄膜,通过FTIR测试了复合薄膜相变过程中的红外透过率图谱,并通过DSC测试了复合粉体的相变温度(Tt)。结果表明两种热处理方法均得到了VO2(M),VO2晶体以蠕虫状附着在云母表面,同时钨的掺入使云母表面的VO2颗粒更加细小。不同掺杂量的复合粉体均表现出较优异的热致变色性能,相变前后在2 200 cm-1波数处的红外透过率变化量(ΔTr)均超过20%。随着nW/nV增加,复合粉体的ΔTr逐渐减小,Tt逐步降低,同时相变陡然性减缓。     

苯甲酸类配体的Co(Ⅱ)配合物合成、晶体结构及光电性能对比

采用水热和溶剂热方法合成了4种Co(Ⅱ)配合物:[Co(btec)0.5(pz)2]n(1),[Co(btec)0.5(pz)3]n(2),[Co(phen)(Hbtc)(H3btc)(H2O)2].3H2O(3)和[Co(Imh)2(anis)2(H2O)](4)(H4btec=1,2,4,5-均苯四甲酸,pz=吡唑;H3btc=1,3,5-均苯三甲酸;phen=1,10-邻菲啰啉;Imh=咪唑;Hanis=对甲氧基苯甲酸)。通过X-射线单晶衍射、元素分析、红外光谱(IR)、紫外-可见-近红外(UV-Vis-NIR)漫反射光谱和表面光电压光谱(SPS)对配合物进行了表征。结构分析表明,配合物1是具有2D结构的Co(Ⅱ)配聚物,Co(Ⅱ)为四配位。配合物2~4中,Co(Ⅱ)均为六配位。配合物2为1D链状结构,分子间通过氢键进一步网联成2D。配合物3和4为分子型配合物,然后再分别由氢键进一步网联成3D和2D。SPS结果显示,4种配合物在300~600 nm范围内都呈现正的光伏响应(SPV),表明它们都具有一定的光-电转换能力。重点是采用SPS技术讨论了配合物结构、空间维度和中心离子配位环境对配合物光电性能的影响,并尝试采用半导体能带理论与配合物的晶体场理论相结合来分析、指认SPS各响应带。