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1999

Materials Science and Engineering

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Articles 1 - 30 of 107

Full-Text Articles in Engineering

Behavior Of Gamma Tial Subjected To Impact Damage And Elevated Temperature Fatigue, Trevor S. Harding, J. Wayne Jones Dec 1999

Behavior Of Gamma Tial Subjected To Impact Damage And Elevated Temperature Fatigue, Trevor S. Harding, J. Wayne Jones

Materials Engineering

Gamma titanium aluminide has received significant attention in recent years as a candidate material for use in aerospace and industrial gas turbine engine applications. In particular, these materials offer significant weight reductions (densities are less than half that of nickel-based superalloys), high specific strength retention at elevated temperature and high specific stiffness which is particularly important in vibrating components such as blades. This combination of weight savings and good mechanical properties has led to the possibility that γ-TiAl may be a suitable replacement for nickel-based alloys, such as Inconel 718, in low pressure turbine blades without significant redesign of the …

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Effects Of Foreign Object Damage From Small Hard Particles On The High-Cycle Fatigue Life Of Ti-6a1-4v, Joseph L. Hamrick Ii Dec 1999

Effects Of Foreign Object Damage From Small Hard Particles On The High-Cycle Fatigue Life Of Ti-6a1-4v, Joseph L. Hamrick Ii

Theses and Dissertations

Thin rectangular samples of Ti-6Al-4V were damaged by four methods to represent foreign object damage found in turbine engine blades: 1) impact with 2 mm and 5 mm diameter glass spheres at 305 m/s, 2) impact with 2 mm and 4 mm diameter steel spheres at 305 m/s, 3) quasi-static displacement controlled indentation using steel chisels with 1 mm, 2 mm and 5 mm diameter tips and 4) shearing notches with a 2 mm diameter chisel point under a quasi-static loading condition. Finite element analysis was used to study the relationship between the stress state created by the plastic damage …

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Electrical And Optical Characterization Of Intrinsic And Ion-Implantation Induced Defects In 6h- And 4h-Sic, Michael B. Scott Dec 1999

Electrical And Optical Characterization Of Intrinsic And Ion-Implantation Induced Defects In 6h- And 4h-Sic, Michael B. Scott

Theses and Dissertations

Deep level transient spectroscopy (DLTS), Hall effect, and cathodolummescence (CL) measurements are used to characterize the intrinsic and ion-implantation induced defects in high-temperature (475 and 500 °C) ion-implanted epitaxial n-type 6H- and 4H-SiC, ion-implanted with Cr, Mg, Ar, N, and P atoms. Comparison of room-temperature and high-temperature ion-implanted 6H-SiC:Mg and :Cr indicate the significance of high-temperature ion implantation on the activation of the ion-implanted atoms and damage-recovery of the crystalline lattice. The effects of high-temperature annealing on both damage-recovery and implanted ion activation are detected and analyzed, from 1200 to 1800 °C. Trap parameters of both damage-related and species-related defects …

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Study On Electrochemical Reduction Properties Of Nitrobenzene, Chuna Ma, Wenkui Zhang, Hui Huang, Yongping Gan Nov 1999

Study On Electrochemical Reduction Properties Of Nitrobenzene, Chuna Ma, Wenkui Zhang, Hui Huang, Yongping Gan

Journal of Electrochemistry

The electrochemical reduction characteristics of nitrobenzene was extensively investigated by using the techniques such as quasi_steady_state polarization,cyclic voltammetry,fast linear potential sweep method and chronoamperometry in this paper.The electroanalytic properties of Cu,Cu_Hg and Cu_Ni electrodes were evaluated.Based on the study of the transient steping behaviour of nitrobenzene to PAP,the reduction mechanism was discussed.The results showed that the transition steps existed on the electrochemical reduction of nitrobenzene in acidic solution,the reactant is also absorbed on electrodes surface. The control step in the reduction of nitrobenzene was ascribed to the diffusion of nitrobenzene and its electrochemical reductive products in the acid solution.

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Photoelectrochemical Studies On The Tio_2 Nanostructured Porous Film Sensitized By Cyanine Dye, Li Zhang, Maizhi Yang, Xuebin Qiao, Yanzhong Hao, Enqing Gao, Shengmin Cai Nov 1999

Photoelectrochemical Studies On The Tio_2 Nanostructured Porous Film Sensitized By Cyanine Dye, Li Zhang, Maizhi Yang, Xuebin Qiao, Yanzhong Hao, Enqing Gao, Shengmin Cai

Journal of Electrochemistry

The photoelectrochemical behaviors of the TiO 2 nanostructured porous film sensitized by cyanine dye were investigated in this paper.The results showed that the excitaed state level matched the conduction band edge of TiO 2 nanoparticle.Therefore the sensitization of the dye can increase the photocurrent intensity of the TiO 2 nanostructured electrode obviously and results in a red-shift of optical absorption from the ultra_violet region to the visible.As a result,the light_to _electricity conversion efficiency was improved evidently,the maximum value of IPCE has reached 12.1%.

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The Preparation Of Flexible Polymeric Anode And The Measurement Of Its Protective Ability For Cathodic Protection, Ailing Du, Heming Zhang, Mingzong Zhang Nov 1999

The Preparation Of Flexible Polymeric Anode And The Measurement Of Its Protective Ability For Cathodic Protection, Ailing Du, Heming Zhang, Mingzong Zhang

Journal of Electrochemistry

The flexible electrode,whose shape can be changed freely,was made of ethenyl copolymer and conductive component and proper amount of additive for cathodic protection.The resistance of electrode was measured.In low concentration of H 2SO 4,the flexible electrode can be used as auxiliary anode to protect the carbon steel.The protection ability of the flexible auxiliary anode was measured too.

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Studies Of The Electrode Preparation Of Electrode From Lead Carbonate For Lead Acid Battery Ⅰ The Activation Of The Pme, Zhongxu Dai, Dihua Wang, Junwei Jiang, Yunhong Zhou, Jinyun Zou Nov 1999

Studies Of The Electrode Preparation Of Electrode From Lead Carbonate For Lead Acid Battery Ⅰ The Activation Of The Pme, Zhongxu Dai, Dihua Wang, Junwei Jiang, Yunhong Zhou, Jinyun Zou

Journal of Electrochemistry

Lead carbonate which was an intermediate product in lead hydrometallurgy without pollution of lead vapor and sulfur dioxide was selected as electrode material of lead_acid batteries. In the present work,the performances of PbO 2/PbSO 4 or PbSO 4/Pb electrode transformed from PbCO 3 have been investigated by powder microelectrode technique combined with cyclic voltammetry.The results show that the CV characteristics of either negative or positive electrode prepared from PbCO 3 is as good as that of both electrodes made from lead oxide produced by mill machine,when a powder microelectrode with PbCO 3 transformed into PbSO 4 in 1.0 mol/L H …

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Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui Nov 1999

Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guangqiang Li, Zhitong Sui

Journal of Electrochemistry

In fuel cells,the structure of electrodes is an important factor which effect the cell performance.To improve the structure and the performance of electrodes,a new method of providing fuel cell electrodes is proposed in this paper.PTFE(polytetrafluoroethylene) and ethyne black was ground for about half an hour in a high_speed grinder,then the catalyst was added into the grinder and milled for an hour.This milled catalyst was transferred into a mixer followed by the addition of surface_active agent. After a suspension was formed,it was filtered under vacuum condition.Then a thin uniform filter_cake of the catalyst was formed,which was rolled together with a current_collecting …

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The Studies Of The (Photo) Electrochemical Character On The Electrodeposited Silver Indium Selenium Thin Films, Shaoai Xie Nov 1999

The Studies Of The (Photo) Electrochemical Character On The Electrodeposited Silver Indium Selenium Thin Films, Shaoai Xie

Journal of Electrochemistry

A photoelectrochemical cell(PEC) is constructed,using an AgInSe 2 film photoanode made from electrodeposition and a platinium electrode in aqueous polyiodide or polysufide electrolyte. The V oc and I sc of PEC have been tested and measured, and the effect of chemical decoration on the photoanodes also studied.

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The Electrochemical Behaviors Of Superoxide Dismutase At Promoter Modified Gold Electrode, Xiaqin Wu, Xiaoyun Meng, Zhesu Wang, Zongrang Zhang Nov 1999

The Electrochemical Behaviors Of Superoxide Dismutase At Promoter Modified Gold Electrode, Xiaqin Wu, Xiaoyun Meng, Zhesu Wang, Zongrang Zhang

Journal of Electrochemistry

The electron_transfer process of superoxide dismutase was investigated by cyclic voltammetry at the 4,4'_dithiodipyridine,L_cysteine,histidine and arginine modified gold wire electrodes repectively.The quasi_reversible behavior was observed at L_cysteine modified gold electrode.An irreversible electrochemical behavior has been observed at hisdinine modified gold wire electrode.

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A Novel Reaction Region Moving Electrode System For Electrochemical Power Sources, Jinkua You, Que Tu, Zhengjian Wang, Jie Sun, Zugeng Lin Nov 1999

A Novel Reaction Region Moving Electrode System For Electrochemical Power Sources, Jinkua You, Que Tu, Zhengjian Wang, Jie Sun, Zugeng Lin

Journal of Electrochemistry

In most of practical rechargeable batteries, charging/discharging process is always concerned with phase_transformation in the solid state. Due to the irreversibility of the phase_transformation, the cyclic performance of the rechargeable batteries are limited. In this paper, a novel reaction_region moving counter electrode system is constructed in our laboratory. The electrode system is operated at room temperature and cycled in solid_liquid phase during charging/discharging processes. With this electrode, the metal_complexes are firstly deposited(i.e. charging process) on the nearest working electrode and gradually extended to those another working electrodes several centimeters away from the counter electrode. The deposite is dissolved again into …

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High Performance Proton Exchange Membrane Fuel Cells, Jingrong Yu, Baolian Yi, Ming Han, Xiaoliang Cheng, Zhigang Shao, Jingxin Zhang Nov 1999

High Performance Proton Exchange Membrane Fuel Cells, Jingrong Yu, Baolian Yi, Ming Han, Xiaoliang Cheng, Zhigang Shao, Jingxin Zhang

Journal of Electrochemistry

Proton_exchange membrane fuel cells(PEMFC) using a perfluorosulfonic acid proton exchange membrane as an electrolyte can simplify water and electrolyte management.In this paper,the effects of thickness of PEM on the performance of PEMFC were studied.The Nafion_112 PEM and low platinum loading E_TEK electrode yielded very high power density,of the order of 0.95 W/cm 2.The energy_conversion efficiency,the degree of platinum utilization and stability for PEMFC using Nafion 112 and E_TEK electrode were also investigated.

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Electro Oxidation Of Phenol On Sno_2/Ti Electrodes Prepared By Thermal Oxidation, Qingsong Zhang, Huihuang Wu Nov 1999

Electro Oxidation Of Phenol On Sno_2/Ti Electrodes Prepared By Thermal Oxidation, Qingsong Zhang, Huihuang Wu

Journal of Electrochemistry

A SnO 2/Ti electrode prepared by thermal oxidation was used as the anode for galvanostatic electrolysis in acidic solution containing phenol, the time_dependances of phenol concentration,chemical oxygen demand in solution(COD)and instantaneous current efficiency were determined during electrolysis.The results show that with the SnO 2/Ti anode instead of Pt,the COD significantly decreases at the same charge passage, and average current efficiency of oxidation increases by three times The mechanism for phenol oxidation at two electrodes was discussed.

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Investigation Of Sodium Hypophosphite Anodic Oxidizing Behavior In The Process Of Acid Electroless Nickel Deposition, Meiyuan Wang, Yafei Kuang, Yan Xu Nov 1999

Investigation Of Sodium Hypophosphite Anodic Oxidizing Behavior In The Process Of Acid Electroless Nickel Deposition, Meiyuan Wang, Yafei Kuang, Yan Xu

Journal of Electrochemistry

The anodic oxidizing behavior of sodium hypophosphite in the process of electroless nickle deposition(pH=5.5) was investigated with the linear potential sweep method and alternating current impedance.The results indicated that,the oxidation of NaH 2PO 2 was a complicated electrochemical process and affected by the concentration of NaH 2PO 2, the temperature of the bath,the sweep rate and the existence of nickel ion. The NaH 2PO 2 electrooxidation reaction was very likely preceded by heterogeneous interface transformation process,which might be the control step of the whole anodic process.

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Method Of Destroying Hazardous Organic Compounds, Dibakar Bhattacharyya, Susan Mawhinney Nov 1999

Method Of Destroying Hazardous Organic Compounds, Dibakar Bhattacharyya, Susan Mawhinney

Chemical and Materials Engineering Faculty Patents

The present invention relates to a method of destroying hazardous vapor phase or aqueous phase organic compound(s) by providing a polymeric siloxane based solvent in a vessel and adding the hazardous organic compound(s) and ozone to the solvent. The solvent may also comprise a mixture of polymeric siloxane based solvent and fluorinated hydrocarbon solvent.

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Reactive Infiltration Of Silicon Melt Through Microporous Amorphous Carbon Preforms, P. Sangsuwan, Surendra N. Tewari, Jorge E. Gatica, M. Singh, R. Dickerson Oct 1999

Reactive Infiltration Of Silicon Melt Through Microporous Amorphous Carbon Preforms, P. Sangsuwan, Surendra N. Tewari, Jorge E. Gatica, M. Singh, R. Dickerson

Chemical & Biomedical Engineering Faculty Publications

The kinetics of unidirectional capillary infiltration of silicon melt into microporous carbon preforms has been investigated as a function of the pore morphology and melt temperature. The infiltrated specimens showed alternating bands of dark and bright regions, which corresponded to the unreacted free carbon and free silicon regions, respectively. The decrease in the infiltration front velocity for increasing infiltration distances is in qualitative agreement with the closed-form solution of capillarity-driven fluid flow through constant-cross-section cylindrical pores. However, drastic changes in the thermal response and infiltration front morphologies were observed for minute differences in the preform's microstructure. This suggests the need …

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Effect Of Interfacial Mobility On Flexural Strength And Fracture Toughness Of Glass/Epoxy Laminates, T. W. H. Wang, Frank D. Blum, Lokeswarappa R. Dharani Oct 1999

Effect Of Interfacial Mobility On Flexural Strength And Fracture Toughness Of Glass/Epoxy Laminates, T. W. H. Wang, Frank D. Blum, Lokeswarappa R. Dharani

Chemistry Faculty Research & Creative Works

Mechanical testing and surface fractography were used to characterize the fracture of E-glass fiber reinforced epoxy composites as a function of the silane coupling agent used. gamma-Aminopropyltriethoxysilane (APS) and delta-aminobutyltriethoxysilane (ABS) were used because these have been shown to have different interfacial mobilities at multilayer coverage. The values of the properties studied generally increased from untreated c, as determined from a Mode I translaminar fracture toughness tests, for the untreated composites (10.5 ± 0.4 kJ/m2) was lower than that for the ABS-treated composites (14.3 ± 2.1 kJ/m2) which was lower than that for the APS-treated composites (17.1 ± 2.4 kJ/m2). …

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Optical Spray Painting Practice And Training System, Richard J. Klein Ii Sep 1999

Optical Spray Painting Practice And Training System, Richard J. Klein Ii

Patents (University of Northern Iowa)

An optical spray painting practice gun emits a shaped optical beam onto a practice surface to simulate an actual paint spray on the surface. The gun preferably uses a class 2 diode laser to generate a laser beam which is reshaped by a collimating lens into a diverging beam that illuminates the practice surface. The collimating lens creates an elongated image on the practice surface having a length corresponding linearly to the distance of the practice gun nozzle to the practice surface as with a conventional spray gun. The illuminated image distorts when the practice gun is not perpendicular to …

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Theoretical And Experimental Investigation On The Low Temperature Properties Of The Nbcr2 Laves Phase, Dan J. Thoma, Chu Fuming, Katherine C. Chen, Paul G. Kotula, Terence E. Mitchell, John M. Wills, Alim Ormeci, Shao Ping Chen, Robert C. Albers Sep 1999

Theoretical And Experimental Investigation On The Low Temperature Properties Of The Nbcr2 Laves Phase, Dan J. Thoma, Chu Fuming, Katherine C. Chen, Paul G. Kotula, Terence E. Mitchell, John M. Wills, Alim Ormeci, Shao Ping Chen, Robert C. Albers

Materials Engineering

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal of the project was to develop methodologies in which to define and improve the properties of NbCr2 so that the high temperature structural applications of alloys based upon this would not be limited by the low-temperature brittle behavior of the intermetallic. We accomplished this task by (1) understanding the defect structure and deformation mechanisms in Laves phases, (2) electronic and geometric contributions to phase stability and alloying behavior, and (3) novel processing of dual phase (Laves/bcc) …

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Cellular/Dendritic Array Tip Morphology During Directional Solidification Of Pb-5.8 Wt Pct Sb Alloy, L. Yu, G. L. Ding, J. Reye, S. N. Ojha, Surendra N. Tewari Sep 1999

Cellular/Dendritic Array Tip Morphology During Directional Solidification Of Pb-5.8 Wt Pct Sb Alloy, L. Yu, G. L. Ding, J. Reye, S. N. Ojha, Surendra N. Tewari

Chemical & Biomedical Engineering Faculty Publications

Cellular/dendritic array tip morphology has been examined in directionally solidified and quenched Pb-5.8 wt pet Sb alloy by a serial sectioning and three-dimensional image reconstruction technique. There is a large scatter in the tip radius, the nearest neighbor spacing, and the mushy zone length, even among the immediately neighboring cells and dendrites. This scatter may be caused by the natural convection (in the mushy zone and in the bulk melt at the array tip), which also produces macrosegregation along the length of the directionally solidified samples. Even in the presence of convection, however, the tip radii are observed to be …

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Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel Sep 1999

Capillary Surfaces In An Exotic Container: Results From Space Experiments, Paul Concus, Robert Finn, Mark M. Weislogel

Mechanical and Materials Engineering Faculty Publications and Presentations

Experimental results from the Interface Configuration Experiment (ICE) performed aboard the Space Shuttle and the Mir Space Station are reported. The experiment concerns fluid interfaces in certain ‘exotic’ containers in a low-gravity environment. These containers are rotationally symmetric and have the property that for given contact angle and liquid volume, a continuum of distinct rotationally symmetric equilibrium configurations can appear, all of which have the same mechanical energy. These symmetric equilibrium configurations are unstable, in that deformations that are not rotationally symmetric can be shown mathematically to yield configurations with lower energy. It is found experimentally, in confirmation of mathematical …

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Structural And Electrochemical Studies On Lithium Manganese Oxide Containing Li + Prepared By Hydrothermal Method For Lithium Ion Batteries, Deyao Liu, Jinkua You, Wei Chu, Yong Yang, Zugeng Lin Aug 1999

Structural And Electrochemical Studies On Lithium Manganese Oxide Containing Li + Prepared By Hydrothermal Method For Lithium Ion Batteries, Deyao Liu, Jinkua You, Wei Chu, Yong Yang, Zugeng Lin

Journal of Electrochemistry

In this paper, Todorokite manganese oxides containing Li + with large tunnel structure(sample M5) have been synthesized by hydrothermal methods from natural manganese oxide nano fiber (sample M4). The structure and composition of the samples were characterized and analyzed by XRD, ICP, TGA and DTA. Its electrochemical behavior as a cathode materials for rechargeable lithium ion insertion were studied by galvanostatic charge/discharge measurements. XRD results show that the sample M4 is mainly composed of Birnessite and Vernadite structure. Although the sample M4 shows a high initial capacity of approximately 150 mAh/g, its performances decrease gradually over 30 cycles. It is …

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Direct Electrolysis Of Seawater On Conducting Film For Microbial Anticorrosion 1. Simulation And Measurement Technique, Weiling Hu, Lingling Wu, Jing Zhou, Jingxin Li, Jin Luo, Zhonghua Lin Aug 1999

Direct Electrolysis Of Seawater On Conducting Film For Microbial Anticorrosion 1. Simulation And Measurement Technique, Weiling Hu, Lingling Wu, Jing Zhou, Jingxin Li, Jin Luo, Zhonghua Lin

Journal of Electrochemistry

Based on the electrochemical micro probe and the weak signal detection technique, simulated test and measurement system were set up by the use of four_electrode cell(including a micro electrode), bipotentiostat, lock_in amplifier and three_dimensional micro manipulating device. Based on the system, the micrometer scale concentration distribution of trace hypochlorite, which is produced by direct electrolysis of seawater on the conducting film for preventing microbial corrosion has been obtained for the first time. Both relationships between concentration of hypochlorite and its reduction current, which is termed an working curve, and between the reduction current of hypochlorite and measured time are reported.

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The Techniques Of The Paired Electrosynthesis, Hongkun Zhang, Dengping Gu Aug 1999

The Techniques Of The Paired Electrosynthesis, Hongkun Zhang, Dengping Gu

Journal of Electrochemistry

In this Paper,we introduce our work on paired electrosynthesis.In conjunction with our research practice,we introduce electrolytic conditions,such as material of electrode ,courrent density and electrolytic temperature etc,as reference for researcher.We categorize the paired electrosynthesis techniques to widen our view on the paired electroorganic synthesis and to promote the deveopments of paired electrosynthesis techniques.

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A Study Of The Corrosion On Bronze, Hongfan Zhu, Hao Zhou Aug 1999

A Study Of The Corrosion On Bronze, Hongfan Zhu, Hao Zhou

Journal of Electrochemistry

The bronze is the treasure in chinese metallic antique, which was typified by product in Shang_Zhou period (three thousands years ago). Because of corrosion, archaeological messages,such as inscription and pattern on the surface of bronze, would be damaged then the value of bronze antique decreased. The bronze disease is a common disease which forms powdery rust on the surface of bronze in atmospheric environment, the powdery rust emerge from under incrusted rust, then spreads, and eventually leads to bronze damaged. This paper investigates the bronze disease. According to the chemical and electrochemical tests in simulated occluded cell, the variation in …

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A Study Self_Passivation Of Passivie Film Of Stainless Steel In Vinylon Aldehyde Solution, Sifu Hu, Chuanbi Xu, Zhuqiu Cheng Aug 1999

A Study Self_Passivation Of Passivie Film Of Stainless Steel In Vinylon Aldehyde Solution, Sifu Hu, Chuanbi Xu, Zhuqiu Cheng

Journal of Electrochemistry

Properties of self_passivation for the anodic passive film of 1Cr18Ni9Ti and the firsthand passive film of SUS 36 stainless steel in vinylon aldehyde solution(H 2SO 4(240 g/L)+Na 2SO 4(70 g/L)+HCHO(25 g/L)+[Fe 3+ ](35.4 mg/L)+[Cl -](240 mg/L) at 70 ℃ were studied by galvanostatic and potentiostatic polarization mesurements. The effects of compponents of vinylon aldehyde solution, i.e. Fe 3+ and Cl -, on the passivation behaviours of stainless steel have also been investigated. The experimental results showed there is a conversion zone of the active/passive state if the area ratio of active/passive state on these stainless steel attained to a critical …

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Study On Synthesizing Of 2_Methylbutanoic Acid By Indirect Electrooxidation, Chongta Zhao, Zeshan Zhu Aug 1999

Study On Synthesizing Of 2_Methylbutanoic Acid By Indirect Electrooxidation, Chongta Zhao, Zeshan Zhu

Journal of Electrochemistry

The working conditions of synthesizing 2_methylbutanoic acid by oxidizing 2_methyl_1_butanol with tetrabutylammonium hydrosulfate(TBAS) or tetrabutylammonium perchlorate(TBAP) as phase transfer catalyst in sulfuric acid Cr(Ⅵ) oxidation medium was studied. The Cr(Ⅵ) oxidation medium could be electrolytic regenerated from Cr(Ⅲ), during above oxidation reaction.Under the optinum condition,the yield of 2_methylbutanoic acid is more than 95%.

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Influence Of Thiourea And Its Derivate On The Process Of Cathodic Electrodeposition Of Copper, Dong Dong, Yunhui Yunhui, Aihong Zou, Yunxia Zhao Aug 1999

Influence Of Thiourea And Its Derivate On The Process Of Cathodic Electrodeposition Of Copper, Dong Dong, Yunhui Yunhui, Aihong Zou, Yunxia Zhao

Journal of Electrochemistry

The effects of thiourea and its derivate on the electrodeposition of copper from the dilute acid sulphate solutions have been studied by using potential sweep techniques at quasisteady state. Limiting current densities( I d),exchange current densities( i 0) and αn are obtained by data processing with the least square method.Thiourea has a depolarizing effect on the copper depositing at concentrations below 8 mg·L -1 ,and a polarizing effect at higher concentration (>10 mg·L -1 ),and it changes the mechanism of copper deposition reaction.Propenyltiourea and Phenylthiourea have a depolarizing effect on the copper depositing,but the mechanism of copper deposition reaction …

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The Effects Of Metallic Cobalt Abbition On The Performance Of Pasted Nickel Electrodes, Anbao Yuan, Jianqing Ding Wanchun Zhang, Shaoan Cheng, Chunan Cao Aug 1999

The Effects Of Metallic Cobalt Abbition On The Performance Of Pasted Nickel Electrodes, Anbao Yuan, Jianqing Ding Wanchun Zhang, Shaoan Cheng, Chunan Cao

Journal of Electrochemistry

The Ni_foam pasted nickel electrodes prepared by coprecipitated Ni 1_X Zn X(OH) 2 with and without cobalt power addition have been studied. The electrode with addition of metallic cobalt showed a higher performance both in discharge capacity and cycle life.It is known from the experiment results that the addition of Co can remarkably increase the active material utilization which is suggested to be improvement of discharge depth due to the conducting CoOOH formed in the first activation charging.The superior capacity during cycling could be attributed to the synergistic action of zinc and cobalt addition,especially to the coprecipitatation of zinc hydroxide …

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A New Method For Preparing Self_Assembled Lipid Bilayers On Pt Electrode, Peng Diao, Dianlu Jiang, Xiaoli Cui, Dengping Gu, Ruting Tong Aug 1999

A New Method For Preparing Self_Assembled Lipid Bilayers On Pt Electrode, Peng Diao, Dianlu Jiang, Xiaoli Cui, Dengping Gu, Ruting Tong

Journal of Electrochemistry

A new method for preparing Pt_supported bilayer lipid membrane(Pt_BLM) on Pt electrode cleaned by high power ultrasound was reported.The reported method was convenient,costing less platinum and could be used to form large_area Pt_BLM as compared with the traditional Pt_wire_cutting method.The electrical properties of Pt_BLM were studied using electrochemical impedance spectroscopy and cyclic voltammetry.Experimental results showed that the values of membrane capacitance and the voltammetric characteristics were consistent with those of Pt_BLM prepared by traditional method.

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