Physical Sciences and Mathematics Commons^™

Oxygen Charge Transfer Reaction At The Pt/Ysz Interface, Yi Jiang, Wenzhao Li, Jingwang Yan, Shizhong Wang

Journal of Electrochemistry

Oxygen Charge transfer reaction has been investigated by various degrees of potential polarization at the Pt/YSZ interface. Anodic and cathodic charge transfer coefficients were found to be unity over the wide range of oxygen partial pressures and temperatures. While the exchange current density of the interface was found dependent on the partial pressure of oxygen in accordance with the relation: i 0=2FK r(K O 2 P O 2 ) 1/4 (1+K O 2 P O 2 ) 1/2 . Several important parameters, such as electrochemical rate constant, equilibrium constant of oxygen adsorption on Pt surface had also been extracted.

Statistical Mechanical Treatment For The Electrical Double Layer At Ities: Analysis Of Mvn Model, Jintian Wu, Shengpei Chen, Wenduan Su

Journal of Electrochemistry

A statistical mechanical treatment for electrical double layer at the interface between two immiscible elecrolyte solution (ITIES) is presented by using grand canonical method based on the MVN model. For the MVN model, the ITIES was represented by that the two space charge regions are separated by an inner layer of the oriented solvent molecules. Assuming that the ions were allowed to penetrated into the solvent compact layer over some distance, then the grand canonical partition function of the inner layer at ITIES can be given. While the mean field approximation is employed to estimate the interactive potential energy of …

Status Of The Research And Development For Fuel Cell Technology Abroad, Naichao Li, Baolian Yi

Journal of Electrochemistry

Status of the research and development for fuel cell technology abroad was overviewed,and at the aim of accelerating the research and development for fuel cell technology in China, the corresponding stategy for our country was recommended.

The Applications Of Poap Ni 2+ Films Modified Electrode As Sensor For Alcohol, B.Z.Hua Hua, W.Y. Hu, Y.Z.Chen Y.Z.Chen

Journal of Electrochemistry

POAP Ni 2+ films modified electrode can electrocatalyzes significantly the oxidation of alcohol. the modified electrode can be used as the electrochemical sensor for the detection of alcohol. But the oxidation of alcohol is effected by the thickness of films、the concentration of nickel ion in films、pH of electrolyte,as well as temperative. All of those conditions have been studied in order to achieve stable response current during the oxidation of alcohol, and the relation between concentration and current has been made. At last the major characteristic parameters, such as the low limitation of concentration、the response time、the ability of antiinterference et al,have …

Corosion　Potential　Imagingat　The　Interfaceofcoating／Metalbyanewelectrochemicaltechnique, Chang-Jian Lin, Xiang-Dong Zhuo, Ji-Dong Chen, Hui Wang, Rong-Zong Hu, Yi Song, Jian-Guang Tan

Journal of Electrochemistry

No abstract provided.

Surface Raman Spectra Of Pyridine And 2 Mercaptopyrimidine Adsorbed On Rough Nickel Electrode, Qunjian Huang, Jinsong Gao, Xiongwei Cai, Bingwei Mao, Mingseng Zheng, Zhongqun Tian

Journal of Electrochemistry

The Raman spectra of pyridine and 2 mercaptopyrimidine (2 MP) adsorbed on bare nickel electrodes roughened by a HNO 3 etching procedure have been obtained for the first time by utilizing a highly sensitive confocal Raman microscope.Their adsorption behaviours are discussed briefly.This primary result illustrates a great potential for in situ Raman spectroscopy in the study of chemical and electrochemical processes of transition metal surfaces.

Electrocatalytic Oxidation Of Some C 2 Compounds(Alcohols, Aldehydes, And Carboxylic Acids) On A Pt/Sb Ad Electrode, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic oxidation behavior of some C 2 compounds(alcohols, aldehydes and carboxylic acids) on a Pt/Sb ad electrode prepared in situ or ex situ UPD was investigated using pontential sweep and rotating disc electrode methods. It is confirmed that Pt/Sb ad electrode show the most electrocatalytical active to the oxidation of aldehyde functional group and only a little activity to the oxidation of hydroxyl group, but no activity for the oxidation of carboxyl group. The experimental results show that the activity of the Pt/Sb ad electrode prepared by ex situ UPD is higher than that prepared by in situ UPD. …

Studies Of Surface Treatment Methods And Their Operating Mechanisms For Activation Of Hydrogen Storage Electrode, Ronghui Hu, Hanxi Yang, Shigang Lu, Shengxian Li, Jingcheng Liu, Chongzhi Yang

Journal of Electrochemistry

Surface treatment methods by use of charge discharge cycling, KBH 4 reduction and KOH etching were parallely investigated for the rapid activation of Mn(NiCoMnAl) 5 electrode. It is found that the MH electrode treated with hot and concentrated KOH solution exhibits rapid and full activation, and also gives lower discharge overvoltage, higher stable capacity and improved cycleability. It is also revealed from SEM, EDAX and ICP analysis that the KOH activation of the electrode proceeds mainly through the enrichment of mischmetal and nickel in surface to form electrocatalytically active surface for hydrogen absorption reaction, but the surface modification with KBH …

Electrochemical Studies Of Zncl 2 Urea Melts, Peng Liu, Qiqin Yang, Guankun Liu, Yexiang Tong

Journal of Electrochemistry

The electric conductivities of ZnCl 2 Urea melts were determined.The influences of temperature and concentration on the conductance have been studied.The cylic voltammetry,potentiostatic electrolysis and open circuit potential time curve after electrolysis,X ray diffraction were used to investigate the electroreduction of Zn 2+ , electrodeposition of zinc on some electrodes in urea metal chlorides melt. The conductivity of urea NaCl ZnCl 2 melt can reach to over 30 ms·cm -1 (125 ℃), and has a liner relationship with temperature from 108 to 140 ℃. The electroreduction of Zn 2+ to zinc is reversible at one step, and CuZn 5 alloy …

Study On Electrode Constructure And Electrical Performance Of Na/S Cell, Jianhua Yang, Jiadi Cao

Journal of Electrochemistry

A sodium wick for sodium electrode and trough shaped performs for sulfur electrode in Na/S cell were designed and investigated. The experiments suggested that the sodium wick for sodium electrode not only improved the discharge performance of cell but also reduced the quantity of sodium utilization, and increased the specific energy of Na/S cell. The trough shaped preform with alumina fibres for sulfur electrode decreased the polarization, improved the charge acceptance and prolonged the life of cell.

Electroluminescent Property Of N Type Porous Si And Its Characterization By Xps And Lima, Guozheng Li, Chenqian Zhang

Journal of Electrochemistry

The chemical composition and structure of electroluminescent porous Si(PS) on n Si, prepared by photoelectrochemical etching method, were investigated by using XPS and LIMA. The results show that electroluminescence(EL) intensity depends on the formation potential of PS. The relation between EL property and the results of XPS and LIMA is also discussed.

A Study Of The Electroplated Fe Cr Ni Alloy Microstructure, Donglin Li, Jianping Liu, Fangzhou Guo, Jianrong Hua

Journal of Electrochemistry

The microstructure of the electroplated Fe Cr Ni alloys from the mixed carboxylic acid solution containing Cr(Ⅲ) and additives were determined with XRD and SEM. Experimental results showed that, under the experimental condition, the phase component、structure of Cu base electroplated Fe Cr Ni alloys had a critical thickness, which was 11 μm and a critical Ni content, which was 32%. Organic additives, formic acid or polyethylene Glycol, mainly affected the surface、cross section morphology of the electroplated Fe Cr Ni alloys. Adding Mo to the electroplated Fe Cr Ni alloys led to remarkable corrosion resistance in concentrated HCl.

Polarographic And Voltammetric Behaviour Of Complex Of Ciprofloxacin With Manganese, Jialing Zhang, Fan Fan, Huizhi Huizhi, Jinghao Pan

Journal of Electrochemistry

In 0.1 mol·L -1 NH 3 NH 4Cl buffer solution(pH 9.2),a sensitive reduction peak of complex of ciprofloxacin (CPFX) with manganese (Mn) was obtained by single sweep oscillopolarograph. The peak potential( Ep ) is -1.61 V(vs.SCE). The peak current ( i p) is proportional to the concentration of Mn(Ⅱ) over the range of 5×10 -6 ～2×10 -5 mol·L -1 . It is possible to be applied to the determination of Mn(Ⅱ). The polarographyic and voltammetric behaviour of complex was studied in detail. The ratio of CPFX∶Mn in the complex was 2∶1. The electrode reaction mechanism was discussed.

Application Of Taguchi Method To Phosphate Coating, Zidong Wei

Journal of Electrochemistry

The problems encountered in phosphating such as unstability of phosphating bath, too much sludge in phosphating and the poor microcosmic formation of phosphating films have been solved by improving the phosphating bath composition and phosphating procedures. As far as the non linear relationship between the coating weight and geometric area of coating in the phosphating of the steel is concerned, the Taguchi Method is used to optimize the phosphating process. The linear relationship between the coating weight and geometric area of coating is finally obtained. The operational property of the present phosphating bath is also dramatically improved by the adoption …

Problems On The Study Of Anodic Films On Pb In Sulfuric Acid Solution(Ⅱ), Houtian Liu, Qunzhou Wang, Yongqin Wan, Weifang Zhou

Journal of Electrochemistry

The conditions for the growth of the different phases in the anodic Pb(Ⅱ) film on Pb in sulfuric acid solution were discussed.

In Situ Studies Of Copper Electrodepostion On Hopg By Using Ecstm, Zhaoxiong Xie, Bingwei Mao, Xiangdong Zhuo, Jiqian Mu, Zhaowu Tian

Journal of Electrochemistry

In this paper, copper electrodepostion on HOPG had been in situ studied by using a homebuilt electrochemical scanning tunneling microscopy (ECSTM). Three dimensional nucleation and subsequent growth of copper crystals were found as the initial stage of copper deposition on HOPG. In the case of lower overpotential or lower concentration of Cu 2+ , the bulk deposited copper layer tended to form smooth terraces, and grow at the edge of steps. The terraces were stable to some extent, which made it possible to be observed with atomic resolution. At a higher overpotential, the crystal size of copper were somehow smaller. …

Electrocatalytic Reduction Of Nitrite In The Presence Of Complex Of Cobalt(Ⅱ) And 1,10 Phenanthroline, Jian Tong, Xiaojun Dang, Hulin Li

Journal of Electrochemistry

The electrochemistry of cobalt(Ⅱ) 1,10 phenanthroline Co(Phen) 2+ 2 complex and its ability to electrocatalyze the reduction of nitrite were studied , we found that this complex could act as a catalyst in alkaline or neutral solution for nitrite reduction. We have investigated the effect of the complex composition on electrocatalytic ability. The effects of pH value, complex concentration, regeneration and activation of electrocatalyst on the catalytic current have been studied and discussed.

The Electroless Nickel For Aluminium Honeycomb Shielded Vent Windows, Ronghua Wang, Jiaqian Bu

Journal of Electrochemistry

This report summarizes the electroless plating process of magnetic nickel and noncrystalline nickel for aluminium honeycomb shielded vent windows. The test results showed that the electroless nickel plating is bright in appearance, even in thickness, excellent in adhesion with aluminium substrate, good in conductivity, magnetism and corrosion resistance. Shielding efficiency obtained was 67～78 dB under 4 GHz～12 GHz frequency. Environmental reliability tests were made for 56 days under two environmental conditions, that is at 85 ℃ and 35 ℃, 95% relative humidity. The EMI shielding technical requirements of the electroless double nickel plating for aluminium honeycomb shielded vent windows of …

Effect Of Halide Ions On The Deposition Of Electroless Nickel, Keping Han, Jingli Fang

Journal of Electrochemistry

The effect of halide ions on the polarization curves and stationary potential of electroless nickel plating process were studied with electrochemical methods. The acceleration and stabilization mechanism of electroless nickel deposition by halide ions also has been discussed.

The Reduction Of Oxygen To Hydrogen Peroxide In An Acidic Trickle Bed Cell Using Graphite Chip Cathode, Zhaoe Lu, Guanyong Zhang, Tiangeng Zhong, Guonu Fang

Journal of Electrochemistry

The authors investigated the electrochemical reduction of oxygen to hydrogen peroxide in 0.05 mol/L H 2SO 4 solution by the trickle bed electrode using graphite chip. The bed dimension was 14×5×0.6 cm. The current efficiency and the concentration of H 2O 2 in the catholyte were determined at various current strengths and various rates of adding the electrolyte. The proper current was 0.15 A. i.e. the current density was 2.1 mA/cm 2 vertical cross section area of the bed. The concentration of H 2O 2 reached 7×10 -3 mol/L with the current efficiency of 0.2. If the concentration of H …

Wear Due To The Physical And Petrographic Properties Of Rocks And Their Dynamic Interactions With Mining Equipment, Christian Poppeliers

Dissertations and Theses

Wear to mining equipment reduces operational efficiency. If wear rates can be predicted, appropriate matching of alloys to the mine' s geologic conditions can aid in improving the operational efficiency. This study addresses rock characteristics which lead to wear. Macroscopic rock tools which lead to wear include sharp edges and comers on rocks. During a rock/equipment interaction, these rock tools cause high point pressures on the surface of the equipment which leads to ductile cutting and gouging of the surface and subsequent removal of metal. Hard mineral grains, or grain tools, produce abrasion as the grains move across equipment surfaces. …

The Flat Phase Of Crystalline Membranes, Simon Catterall, Mark Bowick, Konstantinos N. Anagnostopoulos

Physics - All Scholarship

We present the results of a high-statistics Monte Carlo simulation of a phantom crystalline (fixed-connectivity) membrane with free boundary. We verify the existence of a flat phase by examining lattices of size up to 128^2. The Hamiltonian of the model is the sum of a simple spring pair potential, with no hard-core repulsion, and bending energy. The only free parameter is the the bending rigidity \kappa. In-plane elastic constants are not explicitly introduced. We obtain the remarkable result that this simple model dynamically generates the elastic constants required to stabilise the flat phase. We present measurements of the size (Flory) …

The Flat Phase Of Crystalline Membranes, Mark Bowick, Simon Catterall, Marco Falcioni, Gudmar Thorleifsson, Konstantinos N. Anagnostopoulos

Physics - All Scholarship

We present the results of a high-statistics Monte Carlo simulation of a phantom crystalline (fixed-connectivity) membrane with free boundary. We verify the existence of a flat phase by examining lattices of size up to $128^2$. The Hamiltonian of the model is the sum of a simple spring pair potential, with no hard-core repulsion, and bending energy. The only free parameter is the the bending rigidity $\kappa$. In-plane elastic constants are not explicitly introduced. We obtain the remarkable result that this simple model dynamically generates the elastic constants required to stabilise the flat phase. We present measurements of the size (Flory) …

Abstract Index Interfaces, Muralidharan Janakiraman

Dissertations and Theses

An index in a database system interacts with many of the software modules in the system. For systems supporting a wide range of index structures, interfacing the index code with the rest of the system poses a great problem. The problems are an order of magnitude more for adding new access methods to the system. These problems could be reduced manifold if common interfaces could be specified for different access methods. It would be even better, if these interfaces could be made database-system independent. This thesis addresses the problem of defining generic index interfaces for access methods in database systems. …

Electrochemical And Infrared Studies Of Model Membrane Systems, Mark Anderson

Mark R. Anderson

No abstract is available at this time.

The Structure Of Alkali Halide Dimers: A Critical Test Of Ionic Models And New Ab Initio Results, T. Törring, S. Biermann, J. Hoeft, Richard J. Mawhorter, Robert J. Cave, C. Szemenyei

All HMC Faculty Publications and Research

In semiempirical ionic models a number of adjustable parameters have to be fitted to experimental data of either monomer molecules or crystals. This leads to strong correlations between these constants and prevents a unique test and a clear physical interpretation of the fit parameters. Moreover, it is not clear whether these constants remain unchanged when the model is applied to dimers or larger clusters. It is shown that these correlations can be substantially reduced when reliable information about dimers is available from experiments or ab initio calculations. Starting with Dunham coefficients of the monomer potential determined from microwave measurements, we …

Longevity Of Woodhouse's Toad In Colorado, Richard M. Engeman, E. Marie Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

Little is known about the longevity of amphibians in nature. Records from captive specimens have demonstrated life spans of 10 to 20 yr for a number of anuran species, including 36 yr for Bufo bufo (Duellman WE, Trueb L. 1986. Biology of Amphibians. New York: McGraw-Hill. 670 p). Here, we report on a male Woodhouse's toad (Bufo woodhousii) which appeared in 1978, and has apparently remained since, in a basement window well of a brick home in an unincorporated western suburb of Denver, Colorado (T3S, R69W, 530). In the intervening years no other toads have been observed in …

Jual Obat Aborsi Di Banjarmasin Langsung Tuntas ( Call : 0855 7636 186)-Antar Gojek, Ibnu Suab

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Recent Climate Anomalies And Their Impact On Snow Chemistry At South Pole, 1987 - 1994, Jack E. Dibb, Sallie I. Whitlow

Earth Sciences

Three 2-m deep snowpits sampled at South Pole in 1994 provide detailed (2-cm resolution) profiles of the concentrations of soluble ionic species for the period 1987 - 1994. The most prominent feature is a large concentration spike of SO4 = in snow deposited in 1992 reflecting fallout from the eruptions of Pinatubo and Hudson in 1991. Concentrations of MSA and values of the MSA/(non-sea-salt SO4 =) ratio are elevated for about three years centered on the prominent volcanic signal. These changes appear to be due to the extended 1991 - 1993 El Nino. The overlapping effects of the volcanic eruptions …