Synthesis of Ultrafine Mesoporous Tungsten Carbide by High‐energy Ball Milling and Its Electrocatalytic Activity for Methanol Oxidation

Ultrafine mesoporous tungsten carbide (WC) was prepared from as‐synthesized mesoporous WC using high‐energy ball milling treatment. X‐ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption‐desorption techniques were used to characterize the samples. Brunauer‐Emmett‐Teller (BET) surface areas of WC samples increased with the increasing ball milling time and kept constant at 10–11 m²·g^?1 for over 9 h. The electrocatalytic properties of methanol electro‐oxidation at WC powder microelectrodes were investigated by cyclic voltammetry, chronoamperometry, and quasi‐steady‐state polarization techniques. The results reveal that ball‐milled WC exhibits higher activity for methanol electro‐oxidation than as‐synthesized mesoporous WC. The suitability of ball‐milled WC for methanol electro‐oxidation is better than platinum (Pt) micro‐disk, although the current peak is not as high as the Pt micro‐disk. Moreover, increasing the methanol concentration and reaction temperature promotes methanol electro‐oxidation on ultrafine mesoporous WC.     

Study by ESI‐FTICRMS and ESI‐FTICRMSn of zinc and cadmium thiophenolate complexes used as precursors for the synthesis of II–VI nanosemiconductors

[M₄(SC₆H₅)₁₀][(CH₃)N]₂, [M₁₀L₄(SC₆H₅)₁₆][(CH₃)N]₄ and [Cd₁₇S₄(SC₆H₅)₂₈][(CH₃)N]₂(M = Cd or Zn, and L = S or Se) zinc and cadmium thiophenolates have been studied by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (ESI‐FTICRMS) and tandem ESI‐FTICRMS (ESI‐FTICRMSⁿ). ESI‐FTICRMS demonstrated its ability to characterize and study such compounds, which may be used as precursors of II–VI nanomaterials. The obtained mass spectrum has been found to be highly relevant of the investigated thiophenolate and the fragmentation behavior of some of the detected ions is indicative of its stability. More specifically, it has been demonstrated that ESI in‐source activation or fragmentation experiments conducted in the Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) cell induced the formation of a very stable entity, which corresponds to the general formula M₄L₄ (M = Zn or Cd and L = S or Se). The elimination of SC₆H₅^? and/or M(SC₆H₅)₂ moieties by various activation processes from the studied thiophenolates led systematically to this structure. Copyright © 2009 John Wiley & Sons, Ltd.     

Interfacial constraints on water and proton transport across nafion membranes

Water and proton transport across a Nafion membrane are measured as functions of water activity and applied electric potential with a polymer electrolyte hydrogen pump. Water and proton transport across the membrane must match water and proton transport entering and leaving the electrode/membrane/vapor three phase interfaces at the anode and cathode. At low applied electric potential proton and water fluxes are correlated. At moderate to high applied electric potential the proton current is constant, independent of applied electric potential, while the water transport increases with increasing electric potential. At high applied electric potential water and proton transport become uncoupled at the membrane interfaces; water is transported across the membrane/vapor interface and protons are transported across the membrane/electrode interface. The applied electric potential drives electro‐osmosis to redistribute the water in the membrane. Water redistribution is limited by the interfacial transport of water across the membrane/vapor interface. © 2015 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2015 , 53, 1580–1589     

Comparative studies of polymer‐dispersed liquid crystal films via a thiol‐ene click reaction

In this work, the thiol‐ene click reaction is employed to fabricate polymer‐dispersed liquid crystal (PDLC) films by photoinitiated polymerization. The PDLC films are prepared by systematic variation of key conditions: variety and content of ‐ene monomer, liquid crystal (LC) content, curing time, and curing light intensity. We find that both the morphologies and electro‐optic properties of these films are adjustable. When increasing the length of alkyl main chain of ‐ene monomers, the driving voltages reduce, but in turn, the contrast ratio decreases. Increasing ‐ene monomer content raises the driving voltages as well as the response time, and the increase of LC content lowers the driving voltages but has a negative effect on the contrast ratio. The changes to the curing conditions (both curing time and UV light intensity) can be used to modify the driving voltages, response time, and contrast ratios of PDLC films. These comparative studies will elucidate new insights in commercial applications of intelligent PDLC films.     

增强型电场协助光催化降解有机污染物

以颗粒状ＴｉＯ２为光催化剂,以工苯酚溶液的降解为模型反应,实现了在电场协助下三维光电组合仙化反应,实验发现,在相同的反应条件下,电解反应和光催化反应中苯酚的降解率分别为１０％和３３．６％,而光电组合催化过程中苯酚的降解率为８２．８％,存在明显的协同作用,产生这种协同作用的主要原因是,电解水反应可有效地为光催化反应提供氧源,以及阳极偏压可有效地减少光生电子和空穴的复合,此外,还研究了电量和溶液酸碱性     

Aerolysin纳米孔核酸检测灵敏区域的协同相互作用探索研究

纳米孔单分子检测技术以其简便、快速、高通量及无需标记等特点, 应用于DNA及蛋白质测序, 更有望实现单分子动态构象变化的研究. Aerolysin(气单胞菌溶素)纳米孔道由于其特有的较长的β-桶限域区(β-barrel)及孔内壁丰富的带电荷氨基酸残基, 在单个寡聚核苷酸分子分析中展现出极高的灵敏性. 本设计利用dA₁₄-4-X, dA₁₄-11-X, dA₁₄-4-X-11-X (X=C, T, G)等单个寡聚核苷酸探针分子, 研究了Aerolysin的两个灵敏区域R1和R2, 探索了R1灵敏区域对单个碱基弱相互作用的差异, 实现区分单个碱基差异. 进一步实验证明, R1灵敏区域对单个碱基类型差异的灵敏区分不受R2灵敏区域被碱基A、C、T占位所影响. 然而, 当R2区域被碱基G占位时, 会使R1区域丧失对整个孔道电流的主导性. 本研究有助于理解Aerolysin对单个寡聚核苷酸分子的超灵敏测量机制.     

金属有机配合物的非线性光学特性

从过渡金属有机配合物的中心金属、配体和几何结构的多样性、多变的金属氧化态和金属与配体的电子供－受作用评述了金属有机配合物的二阶、三阶非线性光学效应的分子结构特征和最新进展。参考文献２６篇。     

树状高分子的功能化进展

介绍了近年来高分子化学领域中十分活跃的树状高分子的研究状况,对目前树状高分子的最新功能化进展进行了评述,着重介绍了具有光活性、电活性、生物活性的树状高分子,以及树状高分子与富勒烯的衍生物。     

VPD技术在光电产品总体设计中的应用

从系统工程方法出发，叙述了在光电系统开发的设计阶段采用VPD（Virtual Product Development）技术实现光电产品全数字化拟实平台的方法和过程。     

室温下ZnCdSe-ZnSe组合超晶格的子带跃迁

通过在室温下对ZnCdSe-ZnSe组合超晶格结构的电调制反射谱的测量,观测到分别来自两组超晶格的激子跃迁,由曲线拟合出的跃迁能量与由包络函数近似计算得到的能量相符合。