共振瑞利散射法在抗生素类药物分析中的研究进展

对近6年来共振瑞利散射法在抗生素类药物分析中的研究与应用做了简要综述,主要从反应体系,线性范围,检出限等方面对几大类药物的研究现状进行了介绍。     

铜(Ⅱ)与取代酞酰苯胺酸和β-苯丙氨酸混配配合物的研究

酞酰苯胺酸具有突出的生理活性犤１,２犦,其活性随过渡金属配合物生成而增强犤３,４犦,某些氨基酸是人体蛋白质的结构单元,本文报道了铜?与取代酞酰苯胺酸、苯丙氨酸混配配合物的合成、表征及热分解机理。１实验部分１．１配合物的合成酞酰苯胺酸配体的合成按文献犤５犦进行。酞酰苯胺酸与氢氧化钠按１∶１摩尔比溶于热乙醇,苯丙氨酸与氢氧化钠按１∶１摩尔比溶于蒸馏水,分别得到酞酰苯胺酸和苯丙氨酸的钠盐溶液。合并二配体钠盐溶液并置于５０～６０℃水浴中搅拌,按金属盐与每种配体酸１∶１摩尔比缓慢滴入CuAc２水溶液,即有大量…     

Study on Irradiation Damage of Bi-Doped PbWO4 Crystal

The luminescence and point defects of pure lead tungstate crystals (PbWO₄) and Bismuth (Bi) doping crystal (PbWO₄:Bi)grown by modified Bridgman method are studied. It is found that irradiation results in the great change of the transmission and X-ray excited emission after γ-ray irradiation about 4 Mrad dose. The defects in PbWO₄ crystal have been studied by means of positron annihilation lifetime and X-ray photoelectron spectra. The results show that Bi dopant suppresses the concentrations of positron capture centers and low-valent oxygen ions.After γ-ray irradiation,in the pure crystal the concentration of lead vacancy (V_Pb) is decreased and that of low-valent oxygen increased; on the contrary,in Bi dopant crystal the concentrations of positron capture centers increased and that of low-valent oxygen ions suppressed. It is tentatively proposed that Bi³⁺ dopants would mainly occupy the sites of lead vacancies resulted from Pb volatilization. And irradiation changes the chemical valence of Bi element,which is Bi³⁺→Bi⁵⁺.The Bi⁵⁺ will replace the lattice W⁶⁺ ions and it will cause some (WO₄)^2－ replaced by (BiO₃+V_O)^－.     

Photoluminescence of amorphous carbon films fabricated by layer—by—layer hydrogen plasma chemical annealing method

A method in which nanometre-thick film deposition was alternated with hydrogen plasma annealing (layer-by-layer method) was applied to fabricate hydrogenated amorphous carbon films in a conventional plasma-enhanced chemical vapour deposition system.It was found that the hydrogen plasma treatment could decrease the hydrogen concentration in the films and change the sp^2/sp^3 ratio to some extent by chemical etching.Blue photoluminescence was observed at room temperature,as a result of the reduction of sp^2 clusters in the films.     

Determination of Sr,Zn, Cu and Fe in Licorice by X-ray Fluorescence Spectrometry

Few persons determine the trace elements in the licorice by X-ray fluorescence spectrometry (XRF), because there is no standard samples of the licorice. This paper describes the method to determine Sr,Zn,Cu and Fe in licorice using XRF. The samples are ashed and then determined with the powder process. The measured results are corrected by artificial standard samples.     

N-TiO2/ZnO复合纳米管阵列的掺杂机理及其光催化活性

以ZnO纳米柱阵列为模板, 采用溶胶-凝胶法制备出TiO2/ZnO和N掺杂TiO2/ZnO的复合纳米管阵列. 扫描电镜(SEM)、X射线光电子能谱(XPS)和紫外-可见漫反射吸收光谱(UV-Vis)的结果表明: 两种阵列的纳米管均为六角形结构, 直径约为100 nm, 壁厚约为20 nm; 在N-TiO2/ZnO复合纳米管阵列中, 掺入的N离子主要是以N-Ox、N-C和N-N的形式化学吸附在纳米管表面, 仅有少量的N离子以取代式掺杂的方式占据TiO2晶格O的位置; 表面N物种形成的表面态能级和取代式掺杂导致带隙的窄化, 增强了纳米管阵列的光吸收效率, 促进了光生载流子的分离. 光催化实验结果表明, N离子的掺杂有利于N-TiO2/ZnO复合纳米管阵列光催化活性的提高.     

高效液相色谱紫外检测法测定小麦幼苗中的内源激素

本文从小麦幼苗中提取出三种植物内源激素,并用反相高效液相色谱紫外检测法测定了激素的含量。选择最佳色谱条件及仪器参数,建立了内源激素的高效液相色谱紫外检测法,该法简便,快速,准确度高,重现性好。     

热阴极直流放电等离子体化学气相淀积金刚石膜过程中等离子体环境的研究 *

利用光发射谱和Langmuir探针对热阴极直流放电等离子体化学气相淀积(PCVD)金刚石薄膜的等离子体环境进行了原位诊断 ,根据探针和光谱诊断结果定量地计算了在放电电流密度变化过程中基态氢原子和基态CH基团数密度的变化 ,发现基态和激发态的原子氢和CH基团的数密度均因放电密度增加而提高 .电子密度、CH发射的相对强度均随放电电流密度的增加而线性增加 ,而不同的含碳活性粒子的产生与电子温度的升高有关 .将诊断结果与金刚石的生长相联系 ,表明激发态的原子氢的产生促进了金刚石的生长 ,等离子体环境中电子温度和密度的增加对金刚石生长速率提高起着重要的作用 .     

樟树叶挥发油β-环糊精包合物的制备研究

为解决樟树挥发油易挥发、不稳定的问题,用水蒸气蒸馏法提取鲜樟树叶挥发油,饱和水溶液法制备挥发油β-环糊精包合物,水蒸气蒸馏法再提取包合物挥发油,紫外光谱法分析包合前后挥发油。硅胶G-CMC薄层色谱法对照包合前后挥发油色谱图。包合前后挥发油紫外吸收光谱与薄层色谱图基本一致。β-环糊精能稳定包合樟树挥发油,解络后不会引起主要成分的改变。     

Potassium Acetate/18-Crown-6 Pair: Robust and Versatile Catalyst for Synthesis of Polyols from Ring-Opening Copolymerization of Epoxides and Cyclic Anhydrides†

Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge, because most of the catalysts exhibit poor tolerance to chain transfer agent (CTA). In this contribution, we demonstrated that potassium acetate (KOAc) and 18-crown-6 (18-C-6) combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity. Compared with KOAc, KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains, and thus produce polyester polyols with narrow and monomodal distribution. In addition, polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification (containing about 2% diacid residual as CTA) with an extremely low catalyst loading ([catalyst pair] : [anhydride] : [epoxide] = 1 : 50000 : 250000, [catalyst pair] = 0.0004 mol%). KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures. Ring- opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride, finally producing polyester polyols with ABA-type block structure.