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Articles 4081 - 4110 of 4488

Full-Text Articles in Chemistry

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, Xinhua Xia, Iwasita T., Vielstich W. Feb 1997

Study Of The Nature Of Formic Acid Adsorbates On Rough Pt And Its Interaction With Co, Xinhua Xia, 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 CO2 from adsorbed formic acid is independent of the adsorption potential. Its value of 2.2 demonstrates that the composition of formic acid adsorbates is …


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/dm2 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 shows the …


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 i0 cosωt 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 in …


Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs Jan 1997

Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs

Journal of the Arkansas Academy of Science

We have demonstrated significant photoconductance in indium sulfide thin films prepared by thermal vacuum evaporation ofIn2$3 powders synthesized in-house by chemical precipitation ofInCl3 or In(CH3COO)3, and (NH4)2S or Na2S. The Delta G lambda/Gdark values have been as high as 0.1 in the initial unoptimized films. Excess sulfur (via a mixture of polysulfide and sulfide ions in the synthesis bath) appears to be important in achieving reproducible and large photoconductivities. In2S3 is particularly attractive as a lower toxicity alternative to CdS in optoelectronic applications such as photovoltaic and photoconductive cells.


Electron Shock Waves: Effect Of Current On Electron Temperature And Density, Mostafa Hemmati, Mathues Shane Doss Jan 1997

Electron Shock Waves: Effect Of Current On Electron Temperature And Density, Mostafa Hemmati, Mathues Shane Doss

Journal of the Arkansas Academy of Science

In our attempt to find analytical solutions for breakdown waves, we employ a set of three-component fluid equations. In addition to reporting the method of integration of electron fluid dynamical equations through the dynamical transition region (sheath region), the wave profile for ionization rate, electron number density and electron temperature inside the sheath will be discussed. Also, the effect of the current on electron temperature, electron number density and ionization rate will be reported.


Characterization Of Iron Oxides And Atmospheric Corrosion Of Steel, Sei Jin Oh Jan 1997

Characterization Of Iron Oxides And Atmospheric Corrosion Of Steel, Sei Jin Oh

Physics Theses & Dissertations

The study of corrosion behavior was performed using three different analytical techniques, which provided information on the formation, development and layering of iron oxides on the corrosion products as a function of atmospheric conditions, exposure time and type of steel. In particular, the protective layer formed on weathering steel was investigated as a function of different amounts of alloying elements in the steel, atmospheric conditions and exposure times. Combined together, the results provided a better understanding of the atmospheric corrosion behavior of steel, and formed a part of database of the atmospheric corrosion characteristics.

Accurate characterization of the iron oxides …


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.


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 …


Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅰ. Influences Of Oxidation And Reduction Pretreatment On Anode Performance, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang Nov 1996

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅰ. Influences Of Oxidation And Reduction Pretreatment On Anode Performance, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The influences of the trace oxygen containing functional groups on surface of carbon material on cell performance of carbon anode for lithium ion batteries were studied by means of the pretreament in various oxidant/reductant systems. The results showed that the rich oxygen containing functional groups impaired the cell performance of carbon material anode, and the reduction of these groups in quantity and oxidation degree can increase charge/discharge capacity and improve first charge/discharge efficiency. The reason was also discussed in the light of effects of surface organic groups on decomposition reactivity of electrolyte and formation process of surface passivating film.


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.


High Active Platinum Plated Titanium Electrode, Xiufeng Xiao, Zeshan Zhu, Yanzhen Chen, Wenyun Hu Nov 1996

High Active Platinum Plated Titanium Electrode, Xiufeng Xiao, Zeshan Zhu, Yanzhen Chen, Wenyun Hu

Journal of Electrochemistry

To prepare the adherent and high active platinum plated titanium electrode, ultrasonic agitation technology and the best conditions of electrodeposition were adopted. Ultrasonic agitation technology can be improved the cohesion between coatings and substrate. The activity of electrode has related to the double layer capacity of electrode, which was due to the electrode rugosity.


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

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

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, Jianbin Zheng, Hong Gao Nov 1996

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

Journal of Electrochemistry

In this paper, diphenhydramine hydrochloride, ephedrine hydrochloride, procaine hydrochloride, vitamin B1 and vitamin B6 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.


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.


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

Studies Of Electrochemical Behaviors Of Cytochrome C On Pretreated Gold Electrode, 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.


Electrochemical Studies Of Cyanocobalamin On Silver Electrode, Zhai Jin, Yang Pin, Donghong Zheng, Junwei Zheng, Tianhong Lu Nov 1996

Electrochemical Studies Of Cyanocobalamin On Silver Electrode, Zhai Jin, Yang Pin, Donghong Zheng, Junwei Zheng, Tianhong Lu

Journal of Electrochemistry

The electrochemical characteristics of cyanocobalamin were separately studied on smooth and roughed silver electrode. It was found that the reduction of cyanocobalamin is two one electron steps on roughed silver but one two electron step on smooth electrode. The reason is due to the ability of absorption of the surface of electrode.


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

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

Journal of Electrochemistry

Electronically conducting polypyrrole doped with heteropolyanions K10H3[Nd(SiMo7W4)2]·xH2O(denoted as [Nd(SiMo7W4)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 (CH3)2CO, CH3CN, CH3OH 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 ΛML(NO3)3 values about the same rare …


The Current Distribution On The Anode Surface Of The Seale Oval Tubular Lead Acid Battery, Renao Gu, Jianlin Yao, Zhengfa Deng, Ru Sun, Liren Wu, Zhongsi Jiang, Wangen Miao 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, Liren Wu, Zhongsi Jiang, Wangen Miao

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%.


Study Of Electrochemistry Of Octa-Butyl 2,3-Naphthalocyanine Manganese (Ⅲ) In Nonaqeous Solvents, Suling Yang, Ersheng Liu, Naisheng Chen, Jinling Huang, Xiaoyu Wang, Ping Pu, Wubiao Duan, Yiqun Wu, Xia Zuo Nov 1996

Study Of Electrochemistry Of Octa-Butyl 2,3-Naphthalocyanine Manganese (Ⅲ) In Nonaqeous Solvents, Suling Yang, Ersheng Liu, Naisheng Chen, Jinling Huang, Xiaoyu Wang, Ping Pu, Wubiao Duan, Yiqun Wu, Xia Zuo

Journal of Electrochemistry

The electrochemical behavior of 5,9,14,18,23,27,32,36-Octa-Butyl 2,3-Naphalocyanine Manganese (Ⅲ) [(BuO)8NPcMn(Ⅲ)Cl] in four nonaqueous solvents was studied by means of cyclic voltammetry, and the corresponding half-wave potentials (E1/2) of redox reactions were obtained. Four (or five) pairs of redox peaks were assigned. The solvent effect on the electrochemical characteristics of this coordination compound was also discussed preliminarily, and the electrochemical behavior of the complex was compared with that of nonsubstitued naphthalocyanine.


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 …


Fisheries Research Report No 107 - Chemical Composition Of Yabbies (Cherax Albidus Clark 1936) From Western Australian Farm Dams, Kevin A. Francesconi, Noel M. Morrissy Oct 1996

Fisheries Research Report No 107 - Chemical Composition Of Yabbies (Cherax Albidus Clark 1936) From Western Australian Farm Dams, Kevin A. Francesconi, Noel M. Morrissy

Fisheries Research Reports

Proximate analyses, amino acid and fatty acid profiles, mineral composition and heavy metal and pesticide residues have been determined for tail muscle from Cherax albidus Clark 1936 (the yabby), sampled from Western Australian farm dams. The proximate analysis values for water, protein, ash, carbohydrate and energy content and the amino acid and fatty acid profiles of yabby tail muscle were similar to those reported for other decapods. Fat levels were low and, hence, cholesterol was very low in tail meat. Organochlorine pesticides were undetectable and heavy metal residues were well below maximum permitted concentrations for human consumption.


Cross Sections For The Production Of He+ (Np) 2p0 States By 50 To 150 Kev Proton Impact On Helium, Wayne C. Stolte, R. Bruch Sep 1996

Cross Sections For The Production Of He+ (Np) 2p0 States By 50 To 150 Kev Proton Impact On Helium, Wayne C. Stolte, R. Bruch

Chemistry and Biochemistry Faculty Research

Cross sections have been measured for the production of He+ (np) 2Po states, n=2,3,4, by proton impact on helium over a projectile velocity range of 1.42–2.45 a.u. (50 ≤E≤150 keV). Cross sections were determined by measuring the extreme ultraviolet photons emitted from excited He1 ions. The data indicate a lower energy than expected for the maximum cross section. A comparison of the present results in terms of projectile energy dependance with the cross sections for excitation to He (1snp) 1Po, ionization, and total electron capture suggests the primary mechanism …


Kinetic-Energy- And Angular-Resolved Fragmentation Of Co In Vibrational-Resolved C 1s Excitation, N. Saito, Franz Heiser, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker Sep 1996

Kinetic-Energy- And Angular-Resolved Fragmentation Of Co In Vibrational-Resolved C 1s Excitation, N. Saito, Franz Heiser, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker

Environmental Studies Faculty Publications

Angular distributions of C++O+ from CO were measured, following vibrationally resolved C 1s excitations into the 2pπ, 3sσ, and 3pπ orbitals as well as into higher unresolved orbitals. A time-of-flight mass spectrometer, with a multihit-type position-sensitive anode, was used for the measurements. The anisotropy parameters (β) of C++O+ approach their theoretically expected values as the released kinetic energy in the fragmentation increases. The value of the β parameters remains constant for all vibrational states within each orbital.


First Results From The High-Brightness X-Ray Spectroscopy Beamline 9.3.1 At Als, W. Ng, G. Jones, Rupert C. Perera, D. Hansen, J. Daniels, Oliver Hemmers, P. Glans, S. B. Whitfield, H. Wang, Dennis W. Lindle Sep 1996

First Results From The High-Brightness X-Ray Spectroscopy Beamline 9.3.1 At Als, W. Ng, G. Jones, Rupert C. Perera, D. Hansen, J. Daniels, Oliver Hemmers, P. Glans, S. B. Whitfield, H. Wang, Dennis W. Lindle

Environmental Studies Faculty Publications

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1–6 keV photon energy range. This beamline is designed to achieve the goal of high brightness at the sample for use in the x‐ray atomic and molecular spectroscopy (XAMS) science, surface and interface science, biology and x‐ray optical development programs at ALS. X‐ray absorption and time‐of‐flight photoemission measurements in 2–5 keV photon energy range along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.


A Review Of Differential Electrochemical Mass Spectroscopy Techniqueⅰ. The Principle And Development Of Dems, Fujikawa Keikichi, Li Feng Aug 1996

A Review Of Differential Electrochemical Mass Spectroscopy Techniqueⅰ. The Principle And Development Of Dems, Fujikawa Keikichi, Li Feng

Journal of Electrochemistry

No abstract provided.


Time-Resolved Electron Spin Resonance Spectroscopy For In-Situ Studies Of Electrochemical Systems, Lin Zhuang, Juntao Lu Aug 1996

Time-Resolved Electron Spin Resonance Spectroscopy For In-Situ Studies Of Electrochemical Systems, Lin Zhuang, Juntao Lu

Journal of Electrochemistry

No abstract provided.


Electrodeposition Of Cu-Co Multilayer Thin Films, Jiangyun Xue, Jixun Wu, Dejun Yang Aug 1996

Electrodeposition Of Cu-Co Multilayer Thin Films, Jiangyun Xue, Jixun Wu, Dejun Yang

Journal of Electrochemistry

A method has been developed to produce Cu-Co Multilayer from a single electrolyte by electrodeposition. The effects of the concentration of copper ions, current density and the speed of rotation were investigated, and the Cu-Co electrodeposition films were analysed by TEM, AES and X-ray diffraction. The results indicated that the film was alternating pure copper and coppercobalt alloy layers. If the content of copper in cobalt layer is to be small, the concentration of its ions in solution must be small and the rotation speed must be low.


The Inhibition And Desorption Behavior Of N,N-Dipropynoxy Methyl Amine Trimethyl Phosphonate In Hydrochloride Acid, Tianbao Du, Dianzhen Cao, Jiajian Chen, Chunan Cao Aug 1996

The Inhibition And Desorption Behavior Of N,N-Dipropynoxy Methyl Amine Trimethyl Phosphonate In Hydrochloride Acid, Tianbao Du, Dianzhen Cao, Jiajian Chen, Chunan Cao

Journal of Electrochemistry

The performance of inhibition mechanism and desorption behavior of the N,N-dipropynoxy methyl amine trimethyl phosphonate for iron in hydrochloride acid were investigated by means of static polarization and electrochemical impedance spectroscopy technique. The data of the polarization curves were fitted by weak-polarization fitting technique.The results show that N,N-dipropynoxy methyl amine trimethyl phosphonate possesses high inhibiting efficiency and geometric blocking effect. It is also showed that this inhibitor obeys the Frendulich adsorption isotherm.With the increase of anodic potential, a low-frequency induce arc was observed.