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Articles 2131 - 2160 of 2294

Full-Text Articles in Physical Sciences and Mathematics

An Analysis On The Microstructure Of Electrodeposited Zro 2 Ni Functionally Graded Materials, Chengjun Quan, Xinghua Xiang, Jingchuan Zhu, Zhongda Yin May 1997

An Analysis On The Microstructure Of Electrodeposited Zro 2 Ni Functionally Graded Materials, Chengjun Quan, Xinghua Xiang, Jingchuan Zhu, Zhongda Yin

Journal of Electrochemistry

The electrodeposited ZrO 2 Ni functionally graded coating was fabricated by controlling the ZrO 2 concentration in the bath, and the microstructure was analyzed by X Ray Diffraction (XRD) and Electron Probe Microanalysis (EPMA). The results show that the functionally graded coating has excellent compositional gradient distribution from the substrate to the surface. The content of ZrO 2 is up to 14.4 vol% in the surface layer and the coating consists of the t ZrO 2, m ZrO 2 and Ni phases. Owing to the ZrO 2 particles pressed by Ni atoms during electrodepositing, t→m transformation has occurred.


Studies On Electrodeposition Of Rare Earth Metals And Their Alloys In Molten Salts, Qiqin Yand May 1997

Studies On Electrodeposition Of Rare Earth Metals And Their Alloys In Molten Salts, Qiqin Yand

Journal of Electrochemistry

The cyclic voltammetry, convolution voltammetry, potentiostatic electrolysis and open circuit potential time curve after electrolysis, current time curve at potential step, potential time curve at current step, X ray diffraction, EDAX, electron probe microanalysis were used to investigate the electrode processes of the reduction of rare earth ions on inert electrodes and alloying electrodes in molten chlorides and fluorides. The free energies of formation for the intermetallic compounds, the diffusion coefficients of rare earth ions in the melt, the diffusion coefficients of rare earth atoms in the alloy phases were determined. The alloys of rare earth with iron, cobalt, nickel, …


Polymer Electrolyte Fuel Cell Powered Vehicles, Naichao Li, Baolian Yi May 1997

Polymer Electrolyte Fuel Cell Powered Vehicles, Naichao Li, Baolian Yi

Journal of Electrochemistry

The background, status and commercialization prospect of polymer electrolyte fuel cell vehicles are surveyed in this paper. The technology of this cell and system used in vehicles is discussed.


Problems Of The Study Of Anodic Films On Pb In Sulfuric Acid Solution(Ⅲ), Houtian Liu, Qunzhou Wang, Weifang Zhou Feb 1997

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

Journal of Electrochemistry

The interstitial liquid among the particles in anodic Pb(Ⅱ) films could be the major passage for ion transportation. This is discussed with the mechanism of the cathodic reduction of anodic PbSO 4 film and the effect of Sb on the growth of anodic Pb(Ⅱ) oxides film.


Studies On An Iron Heteropolyacid Redox Flow Battery, Peiju Gu Yuanpeng Sun, Wansheng You, Zhorgyin Tan Feb 1997

Studies On An Iron Heteropolyacid Redox Flow Battery, Peiju Gu Yuanpeng Sun, Wansheng You, Zhorgyin Tan

Journal of Electrochemistry

This paper reports a new Fe HP redox flow cell. The positive and negative electrodes active materials are phosphomolybdic acid and acidified ferrous sulphate solutions respectively. Two activated porous carbon felt electrodes where the electrochemical reactions take place, are separated by a selective cation exchange membrane. The both couples have a suitable electrochemical reversibility on carbon and graphite electrodes. The active materials of the cell have very high stability. Moreover the cell has no life cycle limiting.


Electrochemical Synthesis And Characterization Of Ba Pb O And Bi Pb O Oxides, Min Zhao Liangzhong Xie, Cuiying Xu, Jinbiao Zhang Feb 1997

Electrochemical Synthesis And Characterization Of Ba Pb O And Bi Pb O Oxides, Min Zhao Liangzhong Xie, Cuiying Xu, Jinbiao Zhang

Journal of Electrochemistry

Pb based oxides Ba Pb O and Bi Pb O were synthesized from aqueous solutions by using electrochemical method. The resulting Ba Pb O and Bi Pb O were characterized using XPS, EDX and XRD. The results show that perovskite BaPb 0.9 O 3 can be electrodeposited on the anode only from strong alkaline solution. In acid aqueous solution, conducting BiPb 2O z oxide is fromed on the anode. In these oxides the nominal valence of lead is +4.


Electrochemical Studies Of Spinel Limn 2o 4 Rechargeable Lithium Battery, Li Feng, Yuqin Wu Lie Chang, Hong Li, Yibin San, Tianhong Lu Feb 1997

Electrochemical Studies Of Spinel Limn 2o 4 Rechargeable Lithium Battery, Li Feng, Yuqin Wu Lie Chang, Hong Li, Yibin San, Tianhong Lu

Journal of Electrochemistry

The spinel Li intercalation compound LiMn 2O 4 was prepared and studied using ac impedance and cyclic voltammogram techniques. It was first discussed that the impedance behaviors of LiMn 2O 4 electrode varied as lithium ion was intercalated in or out the electrode with the help of fractal theory. The Li reversible behaviors in LiMn 2O 4 electrode were shown by the cyclic voltammogram results.


Electrochemical Behaviors Of Isoalloxazine Confined In Montomorillonite Olay Modified Electrode, Zhibin Wu, Yuan Lin, Daodao Zhang, Haoqin Wu Feb 1997

Electrochemical Behaviors Of Isoalloxazine Confined In Montomorillonite Olay Modified Electrode, Zhibin Wu, Yuan Lin, Daodao Zhang, Haoqin Wu

Journal of Electrochemistry

A cyclic voltametric investigation of stability and redox properties of isoalloxazne on cetytrimethyammonium bromide(CTAB) modified montomorillonite clay platinium electrode in aqueous solution has been performed. pH dependent film concentrations and apparent diffusion coefficents were measured. The mechanism of the charge transport process with in the clay film were discussed.


Study On The Electrochemical Behavior Of Glycyrrhizic Acid, Chunming Wang, Yanrong Zhang, Hulin Li Feb 1997

Study On The Electrochemical Behavior Of Glycyrrhizic Acid, Chunming Wang, Yanrong Zhang, Hulin Li

Journal of Electrochemistry

The electrochemical response characteristics of glycyrrhizic acid (GA) on the mercury electrode are described. In Britton Robinson buffer, the cyclic voltammograms exhibit two reduction peaks at a potential range of -0.80~-1.60 V.The peak potentials and currents change significantly when solution pH changes. By means of ultraviolet abosrption method, it is proved that the reduction position of GA molecular is ketenes radical. The peak potentials move positively with increasing pH demonstrate that the primary electrode reaction is accompanied by a coupled chemical reaction.The electrode reaction process is a typical example of ECE mechanism. Some effects of various parameters on adsorptive stripping …


The Adsorption Desorption Behaviors Of Β Phenylaminopropiophenone On Iron In Sulphuric Acid Solution, Xianzhang Bu, Dihua Wang, Jinyun Zou, Fuxing Gan Feb 1997

The Adsorption Desorption Behaviors Of Β Phenylaminopropiophenone On Iron In Sulphuric Acid Solution, Xianzhang Bu, Dihua Wang, Jinyun Zou, Fuxing Gan

Journal of Electrochemistry

The adsorption desorption behaviors of β phenylaminopropiophenone (PAP) on iron in 0.5 mol·L -1 H 2SO 4 solution with or without halide ions (Cl -,I -) were investigated by potentiostatic polarization measurement. The results show that the adsorption of PAP on iron surface follows Flory Huggins isotherm, the adsorption free energy parameter ( f ) is positive in H 2SO 4 solution; In the presence of 0.1 mol·L -1 Cl -1 , when C PAP ≤2×10 -5 mol·L -1 , f<0 and when C PAP ≥5×10 -5 mol·L -1 , f>0 . A desorption phenomenon was observed at more positive potential region in anodic polarization curves. Furthermore, the anodic …


Status Of Electroplated And Electroless Plated Thin Film Media For Magnetic Recording, Maozhong An, Zhelong Yang, Jingshuang Zhang, Zhenmi Tu Feb 1997

Status Of Electroplated And Electroless Plated Thin Film Media For Magnetic Recording, Maozhong An, Zhelong Yang, Jingshuang Zhang, Zhenmi Tu

Journal of Electrochemistry

The current study situation for the magnetic recording media films produced by electroplating and electroless plating at aboard was summarized. The bath composition and operating conditions, the properties of the films were introduced. The problem to be solved for extending application of the films was suggested and thd further development was expected.


Co Wc Composite Elecrode, Zeshan Zhu, Xiufeng Xiao, Rongfang Liu, Jingying Shi Feb 1997

Co Wc Composite Elecrode, Zeshan Zhu, Xiufeng Xiao, Rongfang Liu, Jingying Shi

Journal of Electrochemistry

Electrodepositing Co WC composite coatings from cobalt electro bath including WC particles was studied. WC particles accelerate the cathode reaction of composie electrodeposition. In alkaline solution the electrocatalytic properties of evoluting hydrogen were investigated. The results show that the properties of electrode remain superior and stable in a long term interval electrolyzing experiment.


Study Of The Nature Of Formic Acid Adsorbates On Rough Pt And Its Interaction With Co, Xia Xinhua, Iwasita T., Vielstich W. Feb 1997

Study Of The Nature Of Formic Acid Adsorbates On Rough Pt And Its Interaction With Co, Xia Xinhua, Iwasita T., Vielstich W.

Journal of Electrochemistry

The nature of formic acid adsorbates formed on porous platinum electrode has been studied by in situ infrared reflectance spectroscopic (FTIR) and differential electrochemical mass spectroscopic (DEMS) techniques. By carefully avoiding the contamination of the environment( i.e ., air) voltammetric experiments show that the oxidation of formic acid adsorbates depends on both adsorption potential and adsorption time. The online DEMS results show furthermore that the number of electrons necessary for the formation of one molecule of CO 2 from adsorbed formic acid is independent of the adsorption potential. Its value of 2.2 demonstrates that the composition of formic acid adsorbates …


A Study On The Electrodeposition Of Palladium And It′S Nucleation, Fangzu Yang, Shukai Xu, Shibing Yao, Bingyi Chen, Xueqing Zheng, Xiaohui Zhong, Shaomin Zhou Feb 1997

A Study On The Electrodeposition Of Palladium And It′S Nucleation, Fangzu Yang, Shukai Xu, Shibing Yao, Bingyi Chen, Xueqing Zheng, Xiaohui Zhong, Shaomin Zhou

Journal of Electrochemistry

The electrodeposition and nucleation of palladium are studied in the system of potassium citrate and ammonium oxalate. The results show that, with the additives of XP 4 and XP 7 prepared in our laboratory, a full bright palladium electrodeposits will be obtained in the wide ranges of the cathode current densities 0.5~3.5 A/dm 2 and temperature 40~60 ℃; the qualities of the thick deposits will be effectively improved by means of pulse current plating. Cyclic voltammograms results show that the division of peaks between anodic and cathodic on the electrode process of palladium will be up to 1.05 V, which …


Studies On The Cathodic Current Efficiency In The Electrodeposition Ni Psz Gradient Coating, Jun Li, Dianlong Wang, Li Chen, Xinguo Hu Feb 1997

Studies On The Cathodic Current Efficiency In The Electrodeposition Ni Psz Gradient Coating, Jun Li, Dianlong Wang, Li Chen, Xinguo Hu

Journal of Electrochemistry

The cathodic current efficiency and the electrochemical behavior in electrodeposition Ni PSZ gradient coating were investigated by various electrochemical techniques and scanning electron microscope. The results showed that the Ni PSZ composite coatings can accelerate evolution of hydrogen with the increase of PSZ content. The overpotential of nickel reduction will be increased and that of hydrogen reaction will be reduced in the presence of PSZ particles in electrolyte. The effect of PSZ particles on nickel electrodeposition was preferentially to catalyze the formation of H ads . These all contributed to the lower current efficiency.


Ac Electrochemical Thermal Method For Investigating The Entropy Change Of Electrochemical Reaction, Liangjun Dong, Jihua Zhuang, Zhiyu Jiang Feb 1997

Ac Electrochemical Thermal Method For Investigating The Entropy Change Of Electrochemical Reaction, Liangjun Dong, Jihua Zhuang, Zhiyu Jiang

Journal of Electrochemistry

An ac electrochemical thermal method was developed for measuring the entropy change of the electrochemical reaction. When an ac current i 0 cos ωt passed through an electrode in the solution, the heat produced at the surface consisted of several parts. The part varied with frequency ω was caused by the entropy change of the electrochemical reaction, so called the Peltier heat. It could be measured by using a pyroelectric PVDF film detector with a lock in amplifier. This method presents the advantage to inhibit the influence of the polarization heat and Joule heat. The entropy changes of electrochemical reactions …


Study On The Hydrophilicity Of Nafion Membrane Surface, Yanbing Zu, Chuansin Cha Feb 1997

Study On The Hydrophilicity Of Nafion Membrane Surface, Yanbing Zu, Chuansin Cha

Journal of Electrochemistry

Due to its high chemical stability and ion selective permeability, Nafion membrane has been applied in many electrochemical systems. The surface hydrophilicity is one of the main factors affecting its performance. In this paper, the bound bubble method is introduced as a suitable way to measure the contact angles between Nafion membrane and various aqueous solutions. During the measurement, Nafion membrane is saturated with given electrolyt solution. The hysteresis of the contact angles observed in the measurement is attributed to the co existance of hydrophobic and hydrophilic domains at the membrane surface. The effect of the solution surface tension on …


Study On Properties Of Magnesium Alloy Electrode With Anodized Film, Yi Chi, Ping Yang, Xiufeng Lin Feb 1997

Study On Properties Of Magnesium Alloy Electrode With Anodized Film, Yi Chi, Ping Yang, Xiufeng Lin

Journal of Electrochemistry

The corrosion resistance of Mg alloy electrode with anodized film in atmosphere is bigger than that of the Mg alloy electrode with chromate film. The corrosion resisance and voltage delay of such electrode with anodized film in NaCl solution changed with anodizing comdition. The effects of composition, morphology and thickness of the anodized film on the peoperty of Mg alloy electrode are discussed.


Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Batteryⅱ.The Carbon Material With Core Shell Structure And Its Positive Effect On Cell Performance Of Graphite Anode, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang Feb 1997

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Batteryⅱ.The Carbon Material With Core Shell Structure And Its Positive Effect On Cell Performance Of Graphite Anode, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The carbon powders and film electrode with core shell structure were prepared by carbonization in gas state with using refined coal as shell material and Artificial Graphite and Mesocarbon Microbeads (2 800 ℃) graphite as core material. Galvanostatic charge/discharge measurement showed that both steady charge/discharge capacity and first charge/discharge efficiency were improved. Cyclic voltammetry indicated that the peak at about 0.7 V vs. Li +/Li characteristic of decomposition of electrolyte got weakened, and a more compact film was formed. X ray diffraction measurement suggested the existence of amorphous carbon shell on the carbon powders and carbon film.


Progresses In The Studies On Electrochemical And Surface Properties Of Hydrogen Storage Alloy Materials, Yong Yang, Jum Li, Zugeng Lin Nov 1996

Progresses In The Studies On Electrochemical And Surface Properties Of Hydrogen Storage Alloy Materials, Yong Yang, Jum Li, Zugeng Lin

Journal of Electrochemistry

Recent progresses in the studies on electrochemical and surface properties of hydrogen storage alloy materials are reviewed. This paper includes three sections: 1)Thermodynamic and kinetic studies of metal hydride electrodes, 2)Effects of micro structure and alloy elements of the materials on the electrochemical properties of the electrodes and 3)Correlation between surface properties of the alloy materials and performance of the negative electrode in the nickel metal hydride batteries.


Porous Gas Diffusion Oxygen Cathode For Electrodialysis Process, Hongmei Liu, Baolian Yi Nov 1996

Porous Gas Diffusion Oxygen Cathode For Electrodialysis Process, Hongmei Liu, Baolian Yi

Journal of Electrochemistry

In the process of producing silica sols by electrodialysis, with porous gas diffusion oxygen cathode instead of steel cathode, the cell voltage can be reduced 0.86~1.13 V,the power consumption of alkali silica sols (pH=9.5) is about cut down 16%, while the current efficiency has no changing. With porous gas diffusion oxygen cathode instead of steel cathode, the electrolysis electrodialysis process can be returned to electrodialysis process.


Quantitative Evaluation Of Electrochemical Properties Of Mh Alloy By Powder Microelectrode, Ronghui Hu, Hanxi Yang, Jingcheng Liu, Shengxian Li, Chuanxin Cha Nov 1996

Quantitative Evaluation Of Electrochemical Properties Of Mh Alloy By Powder Microelectrode, Ronghui Hu, Hanxi Yang, Jingcheng Liu, Shengxian Li, Chuanxin Cha

Journal of Electrochemistry

In this paper, a quantitative method by use of powder microelectrode combined with cyclic voltammetry and galvanostatic step is described for studying the electrochemical performance characteristic of hydrogen storage alloy(MH). Since the powder microelectrode uses only MH powder and has its depth and diameter of several tens of micrometer, the ohmic and concentration ploarization are greatly reduced and the influences of the technical factors in electrode preparation on the material performance are simply eliminated. Thus, with accurate determination of the load quantity of MH alloy in power microelectrode by absorption spectrometric technique, it is feasible to evaluate quickly and quantitatively …


The Preparation Of Heteropoly Compound Polypyrrole Film Modified Electrode And Its Electrochemical Properties, Weiqing Wang, Xiumei Zhang, Long Cheng Nov 1996

The Preparation Of Heteropoly Compound Polypyrrole Film Modified Electrode And Its Electrochemical Properties, Weiqing Wang, Xiumei Zhang, Long Cheng

Journal of Electrochemistry

Electronically conducting polypyrrole doped with heteropolyanions K 10 H 3[Nd(SiMo 7W 4) 2]·xH 2O(denoted as [Nd(SiMo 7W 4) 2] 13- )was synthesized by electrochemical polymerization. This modified electrode maintains the electrochemical and electrocatalytic properties of heteropolyanion, with having good stability and electrocatalytic activity on the reduction of nitric oxide in acidic aqueous solution.


A Conductance Study Of Complexes Of Rare Earth With Cryptand (2.2) In Nonaqueous Solvents, Shichang Liu, Aiju Xu, Qiang Zhang Nov 1996

A Conductance Study Of Complexes Of Rare Earth With Cryptand (2.2) In Nonaqueous Solvents, Shichang Liu, Aiju Xu, Qiang Zhang

Journal of Electrochemistry

The coordination reaction of several rare earth nitrates with cryptand (2.2) in (CH 3) 2CO, CH 3CN, CH 3OH and DMF at 25 ℃ has been studied by means of using conductometric titration. The stability constants and the molar conductivities for the 1∶1 coordination compounds were calculated. Since the complexation is accompanied by solvation of the Ln(Ⅲ) ion in nonaqueous solvents, for lanthanide series, there is more or less variation in stability constants of complexes of rare earth with cryptand (2.2) when atomic numbers increas. The orders of the Λ ML(NO 3) 3 values about the same rare earth crown …


Poisson Boltzmann Integral Equation In A Charged Capillary And Its Numerical Solutions, Yongxian Qian Nov 1996

Poisson Boltzmann Integral Equation In A Charged Capillary And Its Numerical Solutions, Yongxian Qian

Journal of Electrochemistry

The nonlinear Poisson Boltzmann integral equation (PBIE) governing electrostatic potential distribution in a charged capillary filled with symmetric electrolytes is derived from the same physical principles as used in deriving nonlinear Poisson Boltzmann differential equation, usually called PBE. PBIE is then numerically solved by iteration. In iterate computation discrele values of electrical potential is soly needed, and the first or higher orders of the differential of the potential is not used any more. This does essentially remove the difficulty caused by the very steep variation of the potential near the wall of the capillary. The results of the seven examples …


The Current Distribution On The Anode Surface Of The Seale Oval Tubular Lead Acid Battery, Renao Gu, Jianlin Yao, Zhengfa Deng, Ru Sun Nov 1996

The Current Distribution On The Anode Surface Of The Seale Oval Tubular Lead Acid Battery, Renao Gu, Jianlin Yao, Zhengfa Deng, Ru Sun

Journal of Electrochemistry

The current distribution on anode surface of sealed lead acid batter under different discharge current and degree was studied by chemical analytical method for the first time. We can conclude that the current distribution is not even. The current density on the edge of the electrode surface and the electrode terminal are bigger than other areas, that is, there are edge effect and terminal effect, and these effect are more obvious when the discharge current is 100 A and degree is 100%.


Electrochemical Study And Application Of Cyclodextrin And Its Inclusion Complexes, Shuqin Liu, Zhimin Liu, Jinghao Pan Nov 1996

Electrochemical Study And Application Of Cyclodextrin And Its Inclusion Complexes, Shuqin Liu, Zhimin Liu, Jinghao Pan

Journal of Electrochemistry

The electrochemical investigation and application of cyclodextrin and its inclusion complexes in recent years were reviewed. Studies on electrochemical behaviour of cyclodextrin inclusion complexes in our laboratory were introduced.


Comparison Of The Charge/Discharge Charasteristics Between Ni Cd And Ni Mh Battery And Its Improvement Of Manufacture Technique, Yumimg Wang Nov 1996

Comparison Of The Charge/Discharge Charasteristics Between Ni Cd And Ni Mh Battery And Its Improvement Of Manufacture Technique, Yumimg Wang

Journal of Electrochemistry

Based on the difference of charge discharge charasteristies between Ni Cd and Ni MH battery, some appropriate manufacture technoque to improve the battery performances or to extend its service life are adopted


Determination Of Organic Basis Of Hydrochloride By The Oscillopolarographic Titration, Yongfu Zhan, Zhaoren Meng, Guirong Zhao Nov 1996

Determination Of Organic Basis Of Hydrochloride By The Oscillopolarographic Titration, Yongfu Zhan, Zhaoren Meng, Guirong Zhao

Journal of Electrochemistry

In this paper, diphenhydramine hydrochloride, ephedrine hydrochloride, procaine hydrochloride, vitamin B 1 and vitamin B 6 have been determined by the Oscillopolarographic titration. This method has not been reported in any papers up to now. The characteristics of the method are being quick and exact, easy to observe the final result and saving material tested.


Studies Of Electrochemical Behaviors Of Cytochrome C On Pretreated Gold Electrodereceived 16 May, 1996, Jin Luo, Lingling Wu, Shaohua Huang, Zhonghua Lin Nov 1996

Studies Of Electrochemical Behaviors Of Cytochrome C On Pretreated Gold Electrodereceived 16 May, 1996, Jin Luo, Lingling Wu, Shaohua Huang, Zhonghua Lin

Journal of Electrochemistry

The quasi reversible responses of both adsorbed and bulk cytochrome c at the pretreated gold electrode are observed. The adsorption behaviors and reaction kinetics have been studied using in situ FTIR spectroscopy, UV/Vis reflection spectroscopy, voltammetry, AC impedance and potential step methods. The results show that the cytochrome c can irreversibly adsorb on the gold surface in a complete monolayer and the adsorbed layer can mediate the redox reaction of the cytochrome c in the solution in the absence of promoter.