Solution-phase synthesis and electrochemical hydrogen storage of ultra-long single-crystal selenium submicrotubes

Ultra-long single-crystalline trigonal selenium submicrotubes were synthesized using a facile one-step solution-phase approach with the assistance of nonionic surfactant Polyoxyethylene(20)sorbitan monolaurate (Tween-20), which turned out to be significant for the formation of ultra-long Se submicrotubes. XRD, Raman, SEM, and TEM were adopted to characterize the morphology, structure and phase composition of the as-prepared Se products. It was found that the length of the obtained Se submicrotubes was over 100 microm. By variation of the experimental parameters, the t-Se spheres, nanowires, and broken microtubes can be prepared. The possible growth mechanism of the ultra-long selenium submicrotubes was explained. In addition, we have also demonstrated that the synthesized ultra-long t-Se submicrotubes using the Tween-20-assisted approach can electrochemically charge and discharge with the high capacity of 265 mAh/g (corresponding to 0.97 wt % hydrogen in SWNTs) under normal atmosphere at room temperature. Cyclic voltammetry was adopted to investigate the adsorption-oxidation behavior of ultra-long selenium submicrotubes. It was observed that the morphology of the synthesized selenium products had a remarkable influence on their capacity of electrochemical hydrogen storage. These differences in hydrogen storage capacity are likely due to the size and density of tubes as well as the microcosmic morphology of different Se samples. The as-obtained ultra-long Se submicrotubes are expected to find wide applications in hydrogen storage, high-energy batteries, and optoelectronic, biologic, and catalytic fields as well as in the studies of structure-property relationships. This simple Tween-assisted approach might be extended to the preparations of one-dimensional nanostructures of tellurium and other anisotropic materials.     

Reaction of porous silicon with both end-functionalized organic compounds bearing alpha-bromo and omega-carboxy groups for immobilization of biomolecules

Both end-functionalized (alpha-bromo and omega-carboxy) compounds were first tested for the radical reaction on the silicon-hydride (Si-H) terminated porous silicon (PSi) with/without the presence of diacyl peroxide initiator under microwave irradiation. Then the carboxylic acid monolayers (CAMs) assembled on PSi through the robust Si-C bonds were converted to amino-reactive linker, N-hydroxysuccinimide (NHS)-ester, terminated monolayers. And finally two proteins of bovine serum albumin (BSA) and lysozyme (Lys) were immobilized through amide bonds. The optimum PSi membrane for protein immobilization without collapse, with parameters of porous radii 4-10 nm and depth 0.2-4.6 mum, was prepared from the (100)-oriented p-type silicon wafer. The chemically converted surface products were monitored with Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FESEM).     

Microwave-assisted synthesis of sulfide M2S3 (m = Bi, Sb) nanorods using an ionic liquid

Single-crystalline Bi(2)S(3) and Sb(2)S(3) nanorods have been successfully synthesized by the microwave-assisted ionic liquid method. The starting reagents were Bi(2)O(3) or Sb(2)O(3), HCl, Na(2)S(2)O(3), and ethylene glycol (EG) or ethanolamine, and the ionic liquid used was 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]). Our experiments showed that the ionic liquid played an important role in the morphology of M(2)S(3) (M = Bi, Sb). Single-crystalline Bi(2)S(3) nanorods could be prepared in the presence of [BMIM][BF(4)]. However, urchinlike Bi(2)S(3) structures consisting of nanorods were formed without using [BMIM][BF(4)]. Single-crystalline Sb(2)S(3) nanorods were obtained in the presence of [BMIM][BF(4)]. However, single-crystalline Sb(2)S(3) nanosheets could be prepared in the absence of [BMIM][BF(4)]. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction (ED).     

关于冷原子吸收法测定尿汞影响因素探讨

介绍了对尿汞快速测定法的改进，用消泡剂磷三丁酸消除尿中泡沫，并讨论了尿汞测定的最佳条件，本法的相对标准偏差为４．８－９．０％，回收率９４－１０１％。     

Simultaneous determination of carbohydrates and organic acids in beer and wine by ion chromatography

The simultaneous determination of mono-organic acids and carbohydrates by ion chromatography with both conductometric and pulsed amperometric detection is described. The carbohydrates, such as mannitol, arabinose, glucose, fructose, lactose, sucrose, raffinose, and maltose, as well as monoorganic acids including acetate, glycolate, formate, pyruvate, and fluoride are separated as anions by ion-exchange chromatography with 0.080 mol/L sodium hydroxide eluent at 1 mL/min within 12 min. Carbohydrates are determined by pulsed amperometric detection and mono-organic acids are determined by suppressed conductivity detection. The species in beverages are determined.     

Asymmetric Synthesis. 39.(1) Synthesis of 2-(1-Aminoalkyl)piperidines via 2-Cyano-6-phenyl Oxazolopiperidine

The asymmetric synthesis of a series of 2-(1-aminoalkyl) piperidines using (-)-2-cyano-6-phenyloxazolopiperidine 1 is described. LiAlH(4) reduction of 1 followed by hydrogenolysis led to the diamine 3. The same strategy applied to C-2-methylated compound 7 afforded [(2S)-2-methylpiperidin-2-yl]methanamine (9). Addition of lithium derivatives to the cyano group of 1 resulted in the formation of an intermediate imino bicyclic system (11a-c) which could be diastereoselectively reduced to substituted diamino alcohols 13a-c. The addition of an excess of PhLi to 1 in the presence of LiBr furnished disubstituted amine 19, the precursor of diphenyl[(2S)-piperidin-2-yl]methanamine (22).     

双马来酰亚胺增韧研究Ⅱ.链扩展双马来酰亚胺及其树脂的合成及表征

合成了一系列结构不同和链长短不一的双马来酰亚胺，并对其结构和性能作了表征，同时研究了它们的固化反应和固化产物的性能。用双马来酰亚胺和二烯丙基化合物反应制造了增韧树脂，研究了该树脂的固化和热稳定性。     

铁(III)卟啉催化β-胡萝卜素分解动力学研究

使用BeckmannDU-8B紫外可见分光光度计研究了以氯合四－间三甲苯基卟啉铁（Ⅲ）（FeTMPCl）为催化剂，间氯过氧化苯甲酸（mCPBA）为氧化剂，咪唑（I_m）、2－甲基咪唑（MeI_m）、2－乙基－4－甲基咪唑（EMI_m）为轴向配体，催化β-胡萝卜素（β－cte）氧化分解为维生素A的动力学规律，提出了反应机理，研究了温度、催化剂浓度、氧化剂浓度及轴向配体对反应速率的影响，应用Gauss－Newton－Marquardt方法求得各基元反应的有关动力学参数．     

离子色谱柱切换技术同时测定食品中的多种成分

采用离子色谱柱切换技术同时测定了保留性质差别较大的有机酸以及不同价态的无机阴离子。由于柱切换基本不影响色谱基线,该法有较高的灵敏度。同时测定了食品中的乙酸,山梨酸、苯甲酸、糖精、氯离子和磷酸根。     

Nation-Teflon bimembrane-supported palladium catalysts for Suzuki coupling reactions

Nation-Teflon bimembrane was used as an efficient support for the preparation and application of heterogeneous palladium catalysts.The supported palladium catalysts exhibit high activity and stability in the Suzuki cross-coupling of aryl bromides with arylboronic acids to afford the corresponding biaryls in good to excellent yields,and can be readily recovered and reused several times without significant loss of activity.