Synthesis and Electrospray Ionization Mass Spectra of N-（1,3, 2-Dioxaphosphorinan-2-ylmethyl）thiophosphoramidates

N-（1,3,2-Dioxaphosphorinan-2-ylmethyl）thiophosphoramidates were synthesized and determined by NMR spectra and positive ion electrospray ionization mass spectrometry （ESI-MS） in conjunction with tandem mass spectrometry （MS/MS）. The fragmentation pathways were investigated. The results show that these characteristic ions in ESI mass spectra are useful in the structural determination of N-（1,3,2-dioxaphosphorinan-2-ylmethyl）- thiophosphoramidates.     

EFFECTS OF COUPLING AGENTS ON THE CRYSTALLIZATION BEHAVIOR OF PP/T-ZnOw COMPOSITES

The objectives of this paper are to understand the crystallization behavior of polypropylene(PP)composites with surface modified tetra-needle-shaped zinc oxide whisker(T-ZnOw).T-ZnOw was surface modified with different coupling agents,such as silane coupling agents(KH-550,KH-560)and titanate coupling agent(NDZ-105),in order to improve the compatibility between PP and T-ZnOw.DSC and POM were used to characterize the melt and crystallization behavior and the crystalline structures of the composites,respectively.The results show that the surface modified T-ZnOw acts as a nucleating agent of PP crystallization,depending on the coupling agent used for modification.KH-550 and KH-560 have more apparent role in improving the interfacial interaction than NDZ-105 and induce PP crystallization at higher temperature and with smaller spherulites size.The results also suggest that the crystallization behavior depends on not only the content of coupling agent,but also the content of the surface modified T-ZnOw used in the composites.     

Study on electrochemical behavior of tryptophan at a glassy carbon electrode modified with multi-walled carbon nanotubes embedded cerium hexacyanoferrate

Electrochemical behavior of cerium hexacyanoferrate (CeHCF) incorporated on multi-walled carbon nanotubes (MWNTs) modified GC electrode is investigated by scanning electron microscopy (SEM) and electrochemical techniques. The CeHCF/MWNT/GC electrode showed potent electrocatalytic activity toward the electrochemical oxidation of tryptophan in phosphate buffer solution (pH 7.0) with a diminution of the overpotential of 240 mV. The anodic peak currents increased linearly with the concentration of tryptophan in the range of 2.0 × 10⁻⁷ to 1.0 × 10⁻⁴ M with a detection limit of 2.0 × 10⁻⁸ M (at a S/N = 3). And the determination of tryptophan in pharmaceutical samples was satisfactory.     

吸附溶出伏安法测定水中痕量镉

报道了测定痕量镉的一种新方法．在０．０１ｍｏｌ／ＬＨＡｃ－０．０１ｍｏｌ／ＬＮａＡｃ－１．２×１０－５ｍｏｌ／Ｌ乙醛酸缩氨基硫脲（ＧＡＴＳＣ）体系中，Ｃｄ－ＧＡＴＳＣ产生一灵敏的吸附还原波，波的峰电位是－０．４３Ｖ（ｖｓ·ＳＣＥ），峰电流与镉的浓度在１．０×１０－８～８．０×１０－７ｍｏｌ／Ｌ范围内成直线关系．此法用于测定水中痕量镉，结果令人满意。     

分子电子学的新进展

分子尺度电子学通过构筑基于微尺度电极和单个分子或者少量分子聚集体的"电极-分子-电极"结，研究跨越分子的电荷输运性质.它将分子本征化学特性与器件构筑相结合，考察分子的理化特性与电荷输运的构效关系，揭示微尺度的量子输运动力学原理，并探索基于分子的功能电子器件.是一个集化学、物理学与微电子学为一体的交叉学科.总结整理了分子电子学近些年在器件制备、输运机理及应用方面部分有代表性的进展.     

超高效液相色谱-串联四极杆飞行时间质谱法快速分析东革阿里化学成分

应用超高效液相色谱-串联四极杆飞行时间质谱法(UPLC-Q-TOF-MS)对东革阿里提取物的化学成分进行定性分析。采用Agilent Eclipse Plus-C_(18) RRHD色谱柱(2.1 mm×100 mm,1.8μm),以乙腈-0.1%甲酸水为流动相进行梯度洗脱。质谱分析采用电喷雾正离子模式采集,通过对照品比对及高分辨质谱数据解析,鉴定了49种化学成分,包括29种苦木素二萜、4种β-咔巴啉类生物碱、12种铁屎米-6-酮类生物碱、3种联苯新木脂素类及1种角鲨烯型三萜。该方法快速、可靠、高效,能较全面地反映东革阿里的化学成分,可为深入阐明东革阿里的药效物质基础及质量标准研究提供参考。     

用正电子湮没寿命谱法研究锡镀层缺陷

光亮镀锡工艺由于成本低、无毒、镀层稳定性好而广泛应用于电子元器件引线的电镀.但因锡镀层与基体之间会发生原子的相互扩散,致使产品在储存、焊接或使用期间因温度效应而使某些重要的物理和化学性能,如钎焊性、导电性和防腐性变差。金属界面原子的热扩散行为与金属晶体的结构缺陷密切相关,因此应用正电子湮没寿命谱法研究锡镀层在热处理过程中缺陷的运动规律,在理论和工艺方面都具有重要的意义。     

SrO—Al2O3—SiO2：Eu^3＋,Bi^3＋发光体的溶胶—凝胶法合成

制备无机固体材料大都采用高温固相反应,1971年Dislich报导了用溶胶-凝胶法制备多组份固体材料。近年来,有报导利用此法研制玻璃、玻璃陶瓷和陶瓷。我们在过去工作的基础上,合成了SrO-Al_2O_3-SiO_2:Eu~(3 ),Bi~(3 )发光体,研究了从凝胶至发光晶体的转变过程、Eu~(3 )和Bi~(3 )在SrO-Al_2O_3-SiO_2基质中的发光性质以及Bi~(3 )对 EU~(3 )的能量传递。     

Preferential Oxidation of CO in Excess Hydrogen over CuO-CeO2 Catalyst Prepared by Chelating Method

The CuO-CeO2 catalyst prepared by chelating method has a superior catalytic performance for the preferential oxidation of CO in rich hydrogen, compared with the CuO-CeO2 catalyst prepared by coprecipitation method. The CO conversions over these catalysts, at 120℃and 120000 ml/(g-h) in the absence of CO2 and H2O, are 99.6% and 88.6%, respectively, and the selectivity of O2 over these catalysts is very close (i.e. 51.3% and 55.8%, respectively). The influence of certain factors such as hydrogen concentration, carbon monoxide concentration, H2O, O2/CO ratios, and space velocity on the catalytic performance of CuO-CeO2 catalyst prepared by chelating method is also studied. The results show that the addition of hydrogen and H2O has a negative effect on the catalytic performance of CuO-CeO2 catalyst, however, the variation of space velocity and the O2/CO ratio causes a comparatively slight influence.     

Dually responsive multiblock copolymers via RAFT polymerization: Synthesis of temperature- and redox-responsive copolymers of PNIPAM and PDMAEMA

We report synthesis of temperature- and redox-responsive multiblock copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined α,ω-bis(dithioester)-functionalized poly(N-isopropylacrylamide) (PNIPAM) and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) were prepared using 1,4-bis(thiobenzoylthiomethyl)benzene and 1,4-bis(2-(thiobenzoylthio)prop-2-yl)benzene as RAFT agents, respectively. Dually responsive multiblock copolymers were synthesized in a single aminolysis/oxidation step from the α,ω-bis(dithioester)-terminated PNIPAM and PDMAEMA. The copolymers and their stimulus-responsive behavior were characterized by size exclusion chromatography, NMR, light scattering and atomic force microscopy. Due to the presence of redox-sensitive disulfide bonds between the blocks, the copolymers were readily reduced to the starting polymer blocks. The presence of temperature-responsive PNIPAM blocks provided the copolymers with the ability to assemble into core-shell nanostructures with hydrophobic PNIPAM as a core and cationic PDMAEMA as stabilizing shell when above the phase transition temperatures of PNIPAM. The temperature-induced assembly of the copolymers also showed substantial pH sensitivity. The phase transition temperature increased with decreasing pH, while molecular weight of the assemblies decreased.