GC determination of halogenated olefins by photoionization and hall electrolytic conductivity detectors in series in matrices of hydrofluorocarbons and hydrochlorofluorocarbons

Summary Gas chromatography (GC) with photoionization (PI) and Hall electrolytic conductivity (E1C) detectors connected in series, has been used for the determination of chlorofluorinated olefins. The separation of different standard solutions containing eight chlorofluorinated ethenes in nitrogen and in halogenated matrices has been performed in wide bore capillaries, 0.53 mm i.d., and normal capillaries, 0.32 mm i.d. The quality of separation is obviously influenced by their limited load capacity and by the response time of the Hall detector. At concentrations 1–150 μL L⁻¹ halogenated olefins, both PI and ElC detectors have linear response and can detect minimum levels of 0.2–0.5 ng and 0.4–1.2 ng, respectively. The PID is particularly selective toward halogenated olefins and is extremely useful for the determination of traces of unsaturated halogenated hydrocarbons in a matrix of saturated homologues. The results of this work are of great interest for the detection of chorofluorinated olefins, highly toxic compounds usually formed as by-products in the industrial production of hydrofluorocarbons and hydrochloro-flurocarbons.     

Complexes of lanthanide nitrates with N,N-diethylantipyrine-4-carboxamide

New complexes of lanthanide nitrates with N, N-diethylantipyrine-4-carboxamide (DEAP), with the general formulae [Ln₂(DEAP)₃] [NO₃]₆ (where Ln = La, Pr, Nd, Sm, Tb, Ho, Er, Yb and Y) have been isolated and characterized by chemical analysis and various physical methods such as electrolytic conductance, IR and¹³C NMR spectral data. Electrolytic conductance values and infrared spectral studies indicate that the nitrate groups are coordinated. Infrared and¹³C NMR spectral analysis show that the ligand DEAP is coordinated to the tripositive metal ion through the diethylcarboxamide carbonyl and antipyrine carbonyl oxygens in a bidentate fashion.     

镀锡板镀层测试

以８０９８单片机作智能部件研制开发的对镀锡板度测试装置，采用ＳＴＤ标准总线结构，汉字菜单提示，人－机对话方式操作，采用电解剥离法检测电位跃变曲线，根据电流和起始时间计算出镀层厚度，可直接显示，打印测试曲线和分析结果。     

Electrolytic Iron Sulfide Products in Lithium Batteries

A technology for electrolytic production of iron sulfide compounds applicable in thin-layer lithium batteries is developed. Physicochemical and structural properties and the surface morphology of compounds are studied by x-ray diffraction and thermal analyses, absorption IR spectroscopy, and atomic force microscopy. Specific discharge characteristics of compounds in thin-layer compact nonballast and paste electrodes of model lithium power sources are determined. The discharge capacity of compounds in thin layers weighing 1.0–7.5 mg cm^–2 galvanostatically cycled in electrolyte PC, DME, 1 M LiClO₄ at room temperature stays at 200–320 mA h g^–1 for 40–50 cycles.     

Electrochemical study of manganese and iron compounds at carbon paste electrodes with electrolytic binder. Application to the characterization of manganese ferrite

An electrochemical study of several solids, such as MnCl₂ · 4 H₂O_(s), MnF_3(s), Fe₂O_3(s), Fe₃O_4(s) and MnO_2(s), using carbon paste electrodes with electrolytic binders, is described. Results obtained have been compared with results of earlier electrochemical experiments to carry out the characterization of technological material, such as manganese ferrite. The voltammograms obtained represent the “electrochemical spectra” of solid or dissolved substances that can be used to characterize the material without previous solubilization, as charge transfer processes can proceed in the solid or dissolved state, depending on the solubility in the binder used. Received: 9 December 1996 / Accepted: 14 April 1997     

Stability of chromate electrolytes containing ions of Cr(III)

The reason for the unstable influence of Cr(III) on the maximum rate of incomplete reduction of chromic acid is studied by a method of cyclic voltammetry and analytical investigations of the electrolyte composition. It is established that the decrease in the maximum rate of electrochemical reaction Cr(VI) → Cr(III) is due to the drop of concentration of free sulfate ions in the electrolyte. The drop of the concentration of free sulfate ions increases with the content of electrochemically synthesized ions of Cr(III) in the solution. The decrease in the concentration of sulfate ions is assumed to stem from the formation of unstable complexes of Cr(III) with sulfate ions. Sulfate ions regain their initial concentration with time and upon heating solution to 50–70°C, which facilitates dissociation of unstable sulfate complexes of Cr(III). It is shown that the concentration of sulfate ions in the solution remains invariant during chemical reduction of Cr(VI) to Cr(III), which points to the formation of inert complexes of Cr(III) that make no impact on the rate of incomplete reduction of chromic acid.     

电解还原法合成间苯二胺

在酸性介质中以铜为阴极、石墨为阳极电解还原间二硝基苯制备间苯二胺。考查了温度、电流密度、间二硝基苯用量和盐酸质量百分数对间苯二胺产率的影响及电量对电流效率的影响 ,正交实验确定反应的最佳条件为 :温度 4 0℃ ,电流密度 4A·dm- 2 ,间二硝基苯 0 .2 5g ,HCl质量百分数 15 %。在最佳条件下 ,间苯二胺的产率达 74 .2 %。     

Electrolytic Nickel Oxides in the Electrodes of Lithium Secondary Batteries

A nickel oxide is synthesized for lithium secondary batteries using the suggested technology of electrolysis of aqueous solutions containing Ni²⁺. These oxides are studied by methods of x-ray structure analysis, thermal analysis, and atomic force microscopy in parallel with the determination of electrochemical characteristics. Electrolytic NiO has better specific discharge characteristics and cycle life as compared with other electrolytic nickel oxide compounds. It may be used as cathodic and anodic material in thin-layer lithium batteries.     

一种测定电化学体系中动态相变的原位X—射线衍射实验装置

自制了一种可在Ｘ－射线衍射仪上现场观察电化学反应电极表面物相变化的电解池装置，该装置在使用时，不需对衍射仪部件作任何改变，只需将其固定在衍射仪的测角台上，联结恒电位仪相应接线柱即可。     

Advance in highly efficient hydrogen production by high temperature steam electrolysis

High Temperature Steam Electrolysis (HTSE) through a solid oxide electrolytic cell (SOEC) has been receiving increasing research and development attention worldwide because of its high conversion efficiency (about 45%-59%) and its potential usage for large-scale production of hydrogen. The mechanism, composition, structure, and developing challenges of SOEC are summarized. Current situation, key materials, and core technologies of SOEC (solid oxide electrolytic cell) in HTSE are re- viewed, and the prospect of HTSE future application in advanced energy fields is proposed. In addition, the recent research achievements and study progress of HTSE in Tsinghua University are also intro- duced and presented.