The design of molecules containing planar tetracoordinate carbon

A novel preference for planar tetracoordination was observed over the conventional tetrahedral arrangement in a new series of C₅H₂, C₅H₄, C₅H₄^1+/2+ and related compounds. The stability of these molecules is assessed with the ring-opening barriers, HOMO-LUMO gap, singlet-triplet energy differences and nucleus independent chemical shift values.     

新型的不锈钢镀Pt（Ir）电极

应用欠电位沉积与锚定效应，研制了一种新型的不锈钢镀Ｐｔ（Ｉｒ）电极，此电极具有优越的电化学特性，可望用于微传感器。     

源气体对沉积的a-C∶F∶H薄膜结构的影响

采用微波电子回旋共振等离子体化学气相沉积(MWPECRCVD)方法,使用不同的源气体(CHF3CH4,CHF3C2H2,CHF3C6H6)体系制备了aC∶F∶H薄膜.由于CH4,C2H2,C6H6气体在等离子体中的分解反应不同导致了薄膜的沉积速率和结构上的差异.红外吸收谱的结果表明,用C6H6CHF3作为源气体沉积的薄膜中几乎不含H,而用C2H2CHF3所沉积的薄膜中的含氟量最高,其相应的CF振动峰位向高频方向偏移.薄膜的真空退火结果表明,aC∶F∶H薄膜的热稳定性除了取决于薄膜的CC键浓度外,还与CC键 关键词： 氟化非晶碳膜 电子回旋共振化学气相沉积 红外吸收光谱     

十四烷基三甲基溴化铵对膨润土改性合成及其表征

用阳离子表面活性剂十四烷基三甲基溴化铵(C17H38NBr)对膨润土进行插层改性制备.配制浓度为2.35%十四烷基三甲基溴化铵溶液备用.在碘量瓶中称取3.04g膨润土,加入30mL超纯水、10mL十四烷基三甲基溴化铵溶液,制成土浆,放入微波炉中反应1min.产物经抽滤、洗涤、烘干、研磨,做FT-IR和DSC-TG分析.DSC曲线在500℃时有一明显的放热峰;TG曲线显示改性土的失重率有明显的增大.有机改性膨润土中确实含有大量有机物,改性成功.     

Electrooxidation of carbo/thiocarbohydrazide and their hydrazone derivatives at a glassy carbon electrode

Electrochemical oxidation of thio/carbohydrazide and their hydrazone derivatives Benzaldehyde thiocarbohydrazone [BTCH] diacetylene thiocarbohydrazone [DATCH] have been studied in Brit-ton Robinson buffer in aqueous and nonaqueous media at a glassy carbon electrode. The effects of pH, sweep rate, concentration, temperature and surfactants have been studied. The complex bis (carbo/thiocabohydrazide) Zn(II) chloride was also subjected to voltammetric analysis in order to understand the reactivity both in free and metal bound states. The reaction conditions were optimized for the determination of above compounds in micrograms quantities by differential pulse voltammetry, analytical utility of this investigation is also highlighted.     

H m -modified wave operator for nonlinear Hartree equation in space of dimensionn≥2

We consider the scattering problem for the Hartree equation with potential |x|⁻¹ in a space of dimensionn≥2. We prove the existence ofH ^m -modified wave operator for Hartree equation on a dense set of a neighborhood of zero inH ^m (ℝ ⁿ ), meanwhile, we obtain also the global existence for the Cauchy problem of Hartree equation in a space of dimensionn≥2. This project is supported by the National Natural Science Foundation of China, 19601005     

SPE电极上Pt单组分及Pt-Au双组分还原态CO_2阳极剥离电化学氧化行为研究

采用循环伏安法，对ＳＰＥＰｔ电极以及ＳＰＥＡｕ－Ｐｔ电极上还原态ＣＯ２的电化学氧化行为研究表明，此类电极的电化学特性与光滑Ｐｔ电极一致：ＣＯ２在氢原子吸附电位区０～２５０ｍＶ（ｖｓ．ＲＨＥ）处，可与电极上化学吸附的氢反应，生成还原态的ＣＯ２，通过线性扫描，还原态ＣＯ２即发生一不可逆电化学氧化过程（阳极剥离）．在ＳＰＥＰｔ系列及ＳＰＥＡｕ－Ｐｔ系列上ＣＯ２的电化学行为表明，当ＳＰＥＰｔ系列上Ｐｔ的载量为２．５ｍＬ的０．０１ｍｏｌ·Ｌ－１Ｈ２ＰｔＣｌ６的Ｐｔ时，对还原态ＣＯ２的电催化活性最好，当Ｐｔ的载量相同时，在ＳＰＥＡｕ－Ｐｔ上，催化剂对还原态ＣＯ２的电化学氧化行为比ＳＰＥＰｔ电极更强，这是由于预先沉积的Ａｕ对后沉积的Ｐｔ有调制作用．     

Response to high acidity and basicity at a platinum electrode in chronopotentiometry

A simple and rapid method is developed to determine the high acidity and the basicity of solutions by chronopotentiometry with a platinum working electrode. The acidity range from 5.0 mol/l H⁺ to 1.0 mol/l OH⁻ can be measured by the adjustment of deposition potential and time. The response mechanism to acidity and basicity has been explored. The transition potential plateau in chronopotentiograms is caused from the oxidation of hydrogen adsorbed on electrode surface.     

Influence of boric acid on the electrochemical deposition of Ni

The electrolytic deposition of Ni onto a paraffin-impregnated graphite electrode from supporting chloride electrolyte (0.5 mol dm⁻³ NaCl) adjusted to the required pH using dilute HCl is investigated. The effect of electrolyte composition on the Ni electrodeposition is studied using linear sweep voltammetry in the cathodic region. An elimination voltammetry procedure was applied to evaluate the polarization curves. The aim of this work was to deduce the mechanism of Ni reduction in the chloride bath as well as the influence of boric acid on this. Positively-charged NiCl⁺ ions were found to be the electroactive particles in the Ni reduction mechanism. The strong competition between the NiCl⁺, Cl⁻ and H⁺ ions for active sites at the electrode is discussed. Kinetically-controlled adsorption/desorption processes of various species were also confirmed using elimination voltammetry with a linear scan. The evolution of gaseous hydrogen, catalyzed by the freshly-deposited Ni, accompanies the electrodeposition process. The presence of boric acid at a sufficiently high concentration inhibits the deposition of Ni and, at the same time, improves the morphology and brightness, as well as the adhesion of the deposited Ni. Elimination voltammetry with a linear scan is an efficient way to evaluate current–potential curves that reflect the electrodeposition of one-component Ni coatings. By eliminating selected currents, additional interesting and useful information can be obtained from voltammetric data.