Effect of oxyfluorination on gas sensing behavior of polyaniline-coated multi-walled carbon nanotubes

Polyaniline-coated multi-walled carbon nanotubes were prepared by in situ chemical polymerization method for the novel sensing materials of ammonia gas. The thickness of the polyaniline coatings was controlled by the oxyfluorination treatment on the multi-walled carbon nanotubes. The oxyfluorination with higher oxygen content produced the more hydrophilic functional groups on the surface of multi-walled carbon nanotubes. Both the resistivity change and the response time were significantly improved with high repeatability using the more hydrophilic multi-walled carbon nanotubes which were modified with oxyfluorination.     

Copper-catalyzed three-component one-pot synthesis of quinazolines

Two efficient approaches to multi-substituted quinazolines by the three-component one-pot reaction of o-bromo aromatic ketones/aldehydes, ammonia water and aromatic aldehydes, or primary alcohols catalyzed by CuCl have been developed.     

Relationship between ammonia sensing properties of polyaniline nanostructures and their deposition and synthesis methods

The ammonia absorption properties of polyaniline nanostructures are studied in terms of sensitivity, response and recovery times and stability. These characteristics are obtained by measuring, at room temperature, the absorbance variations at 632 nm. The nanostructures are synthesized either by interfacial or rapid or dropwise polymerizations with the oxidant-to-monomer mole ratio equals to 0.5 or 1. The influence of the deposition method (in-situ or drop-coating technique) as well as the nature of the dopant (HCl, CSA or I₂) on the gas detection properties are also studied. The results show a strong dependence of the morphology on the deposition method, the in-situ technique leads to the best sensitivity and response time. For this deposition method, the nanostructures sensitivity, response time and regeneration rate depend on the synthesis method, the dopant and the mole ratio. The ageing effect after 8 months under ambient conditions and the mechanism of interaction between the polyaniline nanostructures and ammonia molecules are also presented.     

THE CRYSTAL STRUCTURE OF DI-μ-CHLORO-HEXACHLORO-BIS (ETHYL-CYANOFORMATE-N) DITITANIUM (IV)

Abstract

Crystals of the adduct titanium tetrachloride-ethylcyanoformate (1–1) are monoclinic a =9.06 Å, b =18.36 Å, c =13.83 Å, β =113°.2, space group C2/c, Z =8. The structure was solved by application of X-Ray diffraction techniques at room temperature. Atomic positions were refined by a full-matrix least-squares method to a final R of 0.049 using 829 non-zero independent reflections. This compound is dimeric with a double chlorine bridge between titanium atoms. Titanium is octahedrally coordinated to five chlorine atoms and to the nitrogen atom of the nitrile group and not to the oxygen atom of the carbonyl group. Thus in this complex the nitrogen atom is a better donor than the carbonyl oxygen.     

Electrochemiluminescence (ECL) Detection of Ammonium Ion Based on a Novel Iridium Complex Modified Electrode

We report that ammonium ion, as its organic amine counterparts, can be sensitively detected as a coreactant in the electrochemiluminescence (ECL) reaction of a novel iridium complex (pq)₂Ir(N-phMA), where pq is 2-phenylquinoline anion and N-phMA is N-phenylmethacrylamide. The modified ECL electrode was fabricated by casting deposition of a homogeneous MWNTs/PVA/(pq)₂Ir(N-phMA) dispersion solution onto the surface of a glassy carbon electrode. The electrode responds sensitively to ammonium ion in a wide concentration range. Two regression equations were established: Y = 0.7016X + 46.8 (R² = 0.9985) and Y = 0.2565X + 174.2 (R² = 0.9991) for the concentration from 1–180 nM and 180–1800 nM, respectively. The limit of detection was as low as 0.13 nM (S/N = 3).     

离子交换法从醋酸溶液中提取脯氨酸的研究

本文研究了脯氨酸在732,DO01,DH-8三种阳离子交换树脂上的静态吸附特性,发现732树脂的吸附容量最大,速度最快。并选用732树脂,研究了它从醋酸脯氨酸水溶液中吸附脯氨酸的动态过程。最后,以氨水为洗脱剂,考察了不同氨水浓度,洗脱速度对洗脱过程的影响。     

在儿童生长发育中铅的危害与锌的作用

综述了在儿童生长发育中铅的危害与锌的作用。认为铅中毒和锌缺乏将严重影响儿童的生长发育。铅对儿童是以中枢神经系统损坏为主,中构神经毒性最普遍的表现形式是智力和行为的异常。锌被誉为“生命之花”,在人的机体内具有极其重要的生理和生化功能,缺锌儿童发育迟缓、智力差、免疫力低下、食欲不振等。而且,锌能够减少组织中铅的蓄积和铅毒性作用的影响,补锌能有效降低人体铅的含量。葡萄糖酸是唯一被列入非处方药（OTC）目录的理想的有机锌补充剂。     

维汉孕妇及新生儿脐血铅水平与环境因素的相关性研究

为了解乌鲁木齐地区维汉孕妇及新生儿脐血铅现状及相关的影响因素 ,采用石墨炉原子吸收光谱法 ,于 2 0 0 0年 3月～ 9月 ,对新疆医科大学第一附属医院及妇幼保健院正常产妇静脉血及其新生儿脐血进行了血铅测定 (汉族 80例 ,维吾尔族 5 9例 ) ,并对产妇家庭社会环境等相关因素进行了问卷调查。结果表明 ,1 39例产妇血铅 1 2～ 2 67( 84 91± 4 7 64) μg/L ,新生儿脐血铅 1 0～ 32 9( 65 0 8± 4 3 88) μg/L ,维汉母子血铅高度相关 (r =0 71 4 0 ,0 7898,P <0 0 1 )。其中维族孕妇及新生儿脐血铅均大于汉族 (P <0 0 1 ,P <0 0 5 )。血铅≥ 1 0 0 μg/L的孕妇 5 4例( 38 85 % ) ,新生儿 4 9例 ( 35 2 5 % )。研究发现 ,孕期被动吸烟、家庭成员接触铅、家庭周围有铅污染工厂、住址靠马路、母职业、文化程度、孕期补钙、家庭人均收入、母上班乘公共汽车时间等是影响胎儿铅暴露的因素。结论 :本组维汉孕妇及新生儿血铅值有差异 ,且和环境因素有关 ,新生儿铅中毒有一定比例 ,应引起高度重视     

立得益片对铅中毒小鼠(生殖系统、脑、血液、心脏)促排铅的作用

研究了立得益片对铅中毒小鼠促排铅的作用。给小鼠腹腔注射醋酸铅溶液染毒 7d ,建立铅中毒模型后 ,灌胃给药不同剂量立得益片及阳性对照药物EDTA ,极谱法测定不同时间生殖系统、脑、血液、心脏中的铅含量 ,观察及统计立得益片对铅中毒小鼠上述各脏器的促排铅作用。结果表明 ,铅中毒小鼠给药 6、 1 3d后脑、心脏、血液中的铅含量明显下降 ,生殖系统中仅卵巢和子宫中的铅含量在给药 1 3d后 ,立得益片高剂量组与模型对照组有显著性差异 (P <0 0 1 )。提示立得益片对铅中毒小鼠血液及脏器有明显促排铅作用 ,降低机体的铅负荷且存在时效、量效关系     

NxHy-Fe(x=0～2,y=0～3)配位簇的DFT计算

采用杂化密度泛函（DFT）之B3LYP/6-311G**方法研究了NxHy-Fe(x=0～2,y=0～3)配位簇的几何结构和振动光谱。讨论了在纯铁催化剂上,氮分子和氢分子逐步合成氨的反应机理。结果表明,合成氨过程可能经历N2和N2H2物种。在优化结构的基础上,计算了各个模型的振动频率并解释了有关实验结果。