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2001

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Articles 1 - 30 of 63

Full-Text Articles in Engineering Science and Materials

Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis Dec 2001

Hybrid Transient-Parametric Method And System To Distinguish And Analyze Sources Of Acoustic Emission For Nondestructive Inspection And Structural, Health Monitoring, Yuris Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

A nondestructive evaluation (NDE) technique for inspecting or health monitoring of Structures and/or Specimens by analyzing acoustic emission (AE) signals emitted by the Structures and/or specimens. The method and System ana lyzes acoustic emission (AE) signals emitted by structures and/or Specimens. AE Signals emitted by the Structures and/or Specimens are parametrically filtered as a function of parametric filters corresponding to characteristic waveforms of transient AE classes of predefined AE signals. In para metric analysis, the filtering may be pre- or post-recording. In transient AE analysis, the filtering may be prior to transient recording of the transient signals.

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Structural Studies Of Metastable Nanocrystalline Magnesium Titanate Ceramics, Renmei Xu Dec 2001

Structural Studies Of Metastable Nanocrystalline Magnesium Titanate Ceramics, Renmei Xu

Masters Theses

Nanocrystalline magnesium titanate powders were produced using alkoxides of magnesium and titanium for the sol-gel method. High temperature phases which can only be formed at above 1200°C in equilibrium were formed at much lower temperature 600°C in nanometric system. Cation ordering and structural changes in qandilite (Mg2TiO4 ), geikielite (MgTiO3 ) and karrooite (MgTi2O5 ) were studied by Rietveld refinement of neutron powder diffraction data and X-ray photoelectron spectroscopy. Single qandilite phases were obtained in a wide range of Mg:Ti ratios from 2:038:1 to 1.52:1, and appeared to be Mg2-xTi1+x …

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Corrosion Of Steel In Sea-Bottom Mud Of Nothern China Sea Area, Gong-Yu Guo, Jing-Lei Zhang, Bao-Rong Hou, Fang-Ying Yang Nov 2001

Corrosion Of Steel In Sea-Bottom Mud Of Nothern China Sea Area, Gong-Yu Guo, Jing-Lei Zhang, Bao-Rong Hou, Fang-Ying Yang

Journal of Electrochemistry

Corrosion experiments of A3, 16Mn, 20# as well as ZCE36-225 steel were carriedout in southern Bohai sea and Qingdao sea areas. The sea-bottom mud in southern Bohai sea areais the sandy mud and that in Qingdao sea area is pure beach sand. In this experiment, the compareing test of two modes with electric connected and non-electric connected modes was carriedout. The experiment results showed that: 1) The corrosion rate of steel in sea-bottom mud has astrong relation with mud types. The corrosion rates of steels in pure beach sand are much higherthan those in sandy mud. 2) …

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Electrosynthesis Of A New Electroactive Poly(2,2'-Diaminophenyloxydisulfide), Yu-Zhi Su, Yan-Wen Rao, Ye Yang, Mei-Bing Chen, Yin-Ling Qiu, Yong-Hua Zhang, Ke-Cheng Gong Nov 2001

Electrosynthesis Of A New Electroactive Poly(2,2'-Diaminophenyloxydisulfide), Yu-Zhi Su, Yan-Wen Rao, Ye Yang, Mei-Bing Chen, Yin-Ling Qiu, Yong-Hua Zhang, Ke-Cheng Gong

Journal of Electrochemistry

A new electroactive poly (2,2' diaminophenyloxydisulfide) (PDAPD) was successfully synthesized from acetonitrile(AN)/tetrahydrofuran (THF) solutions containing the supporting electrolyte (LiClO4) and the various kinds of acids (HCl, CF3COOH, CCl3COOH) on Pt electrode by consecutive cyclic voltammiry. The effects of the concentrations of supporting electrolyte (LiClO4) and acid (HCl, CF3COOH, CCl3COOH) on electrodepositon of PDAPD film were investigated. The best experimental conditions for electrosynthesis of a highly electroactive conducting polymer film are that the concentrations are 0.1 mol/L and between 0.05 mol/L～0.5 mol/L,respectively for LiClO4 and HCl.

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Studies On The Anti-Corrosion Behavior Of Corrosion Inhibitor To The Ship Building Steel In Moist Air, Yong-Tao Zhao, Jian-Hua Wu, Jia Wang Nov 2001

Studies On The Anti-Corrosion Behavior Of Corrosion Inhibitor To The Ship Building Steel In Moist Air, Yong-Tao Zhao, Jian-Hua Wu, Jia Wang

Journal of Electrochemistry

The anti corrosion behavior of 907A steel, which were covered with thin inibitor layers in moist air, were simulated, The electrochemical measurements, including EIS method and the coulostatic method, were used to atmospheric corrosion monitor (ACM) under thin inhibitor layers to study the mechanism of rust preventiion. the results shown that the mechanism of inhibiting corrosion was different from the steel immersed in inhibitor solutin, the anodic reaction process under thin inhibitor layers had the advantage over that of cathodic for blocking the speed of corrosion. At the later stage of soaking, the blend feature due to the electrochemical process …

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The Investigation Of Prepare Condition For Micropores Membranes From Poly(Vinylidene Fluoride), Xu-Mei Ren, Feng Wu, Ying Bai, Hang-Jun Li, Xue-Jie Huang Nov 2001

The Investigation Of Prepare Condition For Micropores Membranes From Poly(Vinylidene Fluoride), Xu-Mei Ren, Feng Wu, Ying Bai, Hang-Jun Li, Xue-Jie Huang

Journal of Electrochemistry

The micropores membranes from Poly (vinylidene fluoride) were prepared by the phase inversion process. The effects of the casting solution composition, exposure time prior to coagulation and temperature of the coagulation bath on properties of prepared membranes were investigated. For all prepared membranes an asymmetric structure, sometimes without a dense skin layer, was observed.

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An Investigation Of Structural Properties Of Li-Al-Mixed Doped Spinels Materials Li 1+XAlYMn Z-YO4, Zi-Shan Zheng, Zi-Long Tang, Zhong-Tai Zhang, Wan-Ci Sheng Nov 2001

An Investigation Of Structural Properties Of Li-Al-Mixed Doped Spinels Materials Li 1+XAlYMn Z-YO4, Zi-Shan Zheng, Zi-Long Tang, Zhong-Tai Zhang, Wan-Ci Sheng

Journal of Electrochemistry

Al and Li elements were co-doped into host spinel lithium manganese oxide by a simple and economical preparation technology. There was an investigation of the influence of doped Al contents on the initial capacity and cycling performance of the materials. The investigation of the XRD patterns, the analysis of the SEM micrographs and the determination of IR spectroscopy showed that the particles of dopant materials are fine, narrowly distributed and well crystallized, and the bonds Mn-O are stronger than these of undoped materials. The resulted materials have a high initial capacity of 119 mAh/g and good cycling characterization. The capacity …

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Studies On The Properties Of The Anodic Films Formed On Lead- Lanthanum And Lead-Samarium Alloys In Sulfuric Acid Solution, Hou-Tian Liu, Chun-Xuao Yang, Hai-Heng Liang, Jiong Yang, Wei-Fang Zhou Nov 2001

Studies On The Properties Of The Anodic Films Formed On Lead- Lanthanum And Lead-Samarium Alloys In Sulfuric Acid Solution, Hou-Tian Liu, Chun-Xuao Yang, Hai-Heng Liang, Jiong Yang, Wei-Fang Zhou

Journal of Electrochemistry

AC voltammetry, linear sweep voltammetry, and cyclic voltammetry were applied to study the anodic corrosion of Pb, Pb-1.0 at% La and Pb-1.0 at% Sm electrodes in 4.5 mol·dm-3 H2SO4 solution (25 ℃). The experiment results show that samarium can inhibit the anodic corrosion of lead and decrease the impedance of anodic Pb(Ⅱ) film. Lanthanum can also decrease the impedance of the anodic Pb(Ⅱ)film, but the effect is smaller.

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The Research Of Organic Electrolyte Solutions For Li-Ion Batteries, Quang-Chao Zhuang, Shan Wu, Wen-Yuan Liu, Zhao-Da Lu Nov 2001

The Research Of Organic Electrolyte Solutions For Li-Ion Batteries, Quang-Chao Zhuang, Shan Wu, Wen-Yuan Liu, Zhao-Da Lu

Journal of Electrochemistry

The characteristics of organic electrolyte solutions and its influences on the ion conductivity are summarized. The chemistry and electrochemistry of organic electrolyte solutions and characteristics of ordinary organic solvents are introduced. Progresses in studies of organic electrolyte solutions such as electrolyte salts, organic solvents, additives in recent years are reviewed, current situation of the studies of organic electrolyte solutions were also discussed.

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Thermal Effects On The Measurement Of Photocurrent At Anodic Films On Silver Electrode, Yuan Gu, Zhi-Yu Jiang Nov 2001

Thermal Effects On The Measurement Of Photocurrent At Anodic Films On Silver Electrode, Yuan Gu, Zhi-Yu Jiang

Journal of Electrochemistry

The influence of heat on the photocurrent of Ag electrde in alkaline solution was investigated by measuring photocurrent, photothermal signal and thermal current under the irraiation of laser beams with the wavelengths of 488 nm and 532 nm. It was found the photocurrent atthe Ag2O film was influenced by the temperature change at the electrode surface under the irradiation of light. During the electrochemical transfer between Ag, Ag2O and AgO in the anodic filmthe surface temperature changed obviously due to the different absprptance of the surface subrstances.It was suggested by comparing the voltammograms, photocurrent curves and …

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Study Of Hydrogen Diffusion Behavior In Hydrogen Storage Alloy Mlni3.75Co0.65Mn0.4Al0.2 With Potential Step Method, Xian-Xia Yuan, Nai-Xin Xu Nov 2001

Study Of Hydrogen Diffusion Behavior In Hydrogen Storage Alloy Mlni3.75Co0.65Mn0.4Al0.2 With Potential Step Method, Xian-Xia Yuan, Nai-Xin Xu

Journal of Electrochemistry

Potential step method was employed to study the hydrogen diffusion behavior in hydrogen storage alloy MlNi3.75 Co0.65Mn0.4Al0.2 with various depth of discharge (DOD) at ambient temperature and with 50% DOD at various temperatures. It was found that hydrogen diffusion cofficient in the hydrogen storage alloy increaes with the increase in DOD at ambient temperature. and for the alloy with 50% DOD, the hydrogen diffusion coefficient increases with the increase in temperature and the activation energy for hydrogen diffusion in the alloy is 19.87 kJ/mol.

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Research Progress On Proton Exchange Membranes Of Fuel Cells, Jing-Rong Yu, Dan-Min Xing, Fu-Qiang Liu, Jian-Guo Liu, Bao-Lian Yi Nov 2001

Research Progress On Proton Exchange Membranes Of Fuel Cells, Jing-Rong Yu, Dan-Min Xing, Fu-Qiang Liu, Jian-Guo Liu, Bao-Lian Yi

Journal of Electrochemistry

The proton exchange membrane fuel cells (PEMFC) use proton exchange membranes(PEM) as their electrolytes. The performance of the PEMFC is strongly dependent on the characteristics of the PEM. In this paper, the requirements of the PEM utilized in the PEMFC were analyzed. The per-fluorinated, partially fluorinated and non-fluorinated PEM were introduced respectively. The structures, preparation, properties of the various types of PEM and their applications in the PEMFC were also discussed in detail.

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The Influence Of Synthesis Conditions On The Electrochemical Properties Of Spinel Limn2O4, Jun-Feng Xu, Zhi-Yu Jiang Nov 2001

The Influence Of Synthesis Conditions On The Electrochemical Properties Of Spinel Limn2O4, Jun-Feng Xu, Zhi-Yu Jiang

Journal of Electrochemistry

The electrochemical properties of spine LiMn2O4 synthesized via a solid state reaction were investigated. Electrolysis MnO2(EMD), Li2CO3 ,LiOH and LiNO3 were used as the initial materials. It was found that the electrochemical properties of LiMn2O4 were strongly influenced by the synthesis conditions. The LiMn2O4 sample sprepared via the reactionof EMD and LiNO3 showed the best properties for a lithiumion intercalation reaction. The procedure includes two steps:pretreatment at 280 ℃ for 6 hours to initiate the permeation of melting LiNO3 into the microporesof EMD …

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Adsorption And Oxidation Of Methanol On Pt And Sb, S Modified Pt Electrodes Using Cyclic Voltammetry And Eqcm, Guo-Liang Chen, Sheng-Pei Chen, Heng Lin, Xing-Hong Zheng, Shi-Gang Sun Nov 2001

Adsorption And Oxidation Of Methanol On Pt And Sb, S Modified Pt Electrodes Using Cyclic Voltammetry And Eqcm, Guo-Liang Chen, Sheng-Pei Chen, Heng Lin, Xing-Hong Zheng, Shi-Gang Sun

Journal of Electrochemistry

The processes of adsorption and oxidation of methanol on Pt, Pt/Sb ad and Pt/S ad electrodes were studied by using cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The results demonstrated that the oxidation of methanol depends strongly on oxidation states of electrode surface. Sb adatoms on Pt surface can adsorb oxygen at relatively low potentials, and exhibit catalytic effects for methanol oxidation. In contrast to Pt electrodes, the oxidation peak potential of methanol in this case negatively shifted to about 130 mV. In a contrary, the oxidation of Sad atoms consumes oxygen species of Pt electrode surface. As …

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Study On The Anticorrosion Of Ld-2 Compound Inhibitor On Reinforcing Steel In Seawater, Rong-Gui Du, Zhou-Cheng Wang, Ruo-Shuang Huang, Rong-Gang Hu, Bing Zhao, Jian-Guang Tan, Chang-Jian Lin Nov 2001

Study On The Anticorrosion Of Ld-2 Compound Inhibitor On Reinforcing Steel In Seawater, Rong-Gui Du, Zhou-Cheng Wang, Ruo-Shuang Huang, Rong-Gang Hu, Bing Zhao, Jian-Guang Tan, Chang-Jian Lin

Journal of Electrochemistry

The effect of LD-2 compound inhibitor developed in our laboratory on its anticorrosion action on the reinforcing steel in concrete immersed in seawater was shown in this paper. The corrosion behavior of the reinforcing steel in seawater was studied using electrochemical techniquesand immersion tests. The polarization curve of the reinforcing steel immersed in seawater showedthe free corrosion potential of the steel increased by 0. 220 V (vs. SCE), and the corrosion current decreased by two orders of magnitude by adding 25 g⋅L-1 compound inhibitor to the seawater. The potentiodynamic anodic polarization curve of reinforcing steel in the seawater with …

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Crash Attenuation System, John D. Reid, John R. Rohde, Dean L. Sicking Oct 2001

Crash Attenuation System, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A crash attenuation system having an impact head, and energy absorption mechanism. The energy absorbing mechanism has a mandrel for rupturing thin-walled tubes in a controlled rupture to absorb impact forces from a colliding vehicle. A frame may be used to mount the system to a truck, trailer, guardrail, median barrier end treatment, or a crash cushion. Stress concentrators may be incorporated into the tubes and the mandrels to selectively control rupturing and energy dissipation.

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On Misorientation Distribution Evolution During Anisotropic Grain Growth, Elizabeth A. Holm, Gregory N. Hassold, Mark A. Miodownik Sep 2001

On Misorientation Distribution Evolution During Anisotropic Grain Growth, Elizabeth A. Holm, Gregory N. Hassold, Mark A. Miodownik

Physics Publications

In order to study the development of texture and boundary character during annealing, three-dimensional grain crystallography and crystallographically mediated grain boundary properties were incorporated into a finite temperature Monte Carlo model for grain growth. Randomly textured microstructures evolve normally, with growth exponent n=0.96. While texture remains random, the steady-state boundary misorientation distribution favors low-angle boundaries. To first order, low-angle boundaries increase by lengthening, not by proliferating. In contrast, microstructures with a strong single-component texture develop four-grain junctions and highly curved grain boundaries, which alter evolution. The boundary misorientation distribution narrows and shifts to low angles, and no steady state …

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Current Oscillations In The System Of Carbon Steel/Phosphoric Acid/Platinum, Shao-Yuan Shi, Jin-Ping Wu, Jing Liu, An Lin Aug 2001

Current Oscillations In The System Of Carbon Steel/Phosphoric Acid/Platinum, Shao-Yuan Shi, Jin-Ping Wu, Jing Liu, An Lin

Journal of Electrochemistry

The periodic,aperiodic, chaotic and mixed-mode oscillations can occur in the process of the anodic electrodissolution of carbon steel in the solution of dilute phosphoric acid. More plentiful dynamic behaviors can be found in this system compared with the system of Fe/H3PO4/Pt.

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The Activation Mechanism Of Al Alloys With Tin And Gallium In Alkaline Electrolytes, Zhen-Ya Li, Ling Yi, Zhi-Hui Liu, Lin Yang, Jing-Xin Su, Yan-Ying Chen Aug 2001

The Activation Mechanism Of Al Alloys With Tin And Gallium In Alkaline Electrolytes, Zhen-Ya Li, Ling Yi, Zhi-Hui Liu, Lin Yang, Jing-Xin Su, Yan-Ying Chen

Journal of Electrochemistry

The major reason for Al-anode's activation is that Ga and Sn deposit on the aluminum surface and form activated points. The Al-Sn and Al-Ga binary alloys can't be activated in alkaline medium. During the dissolution of the Al-Sn-Ga ternary anode, Sn and Ga dissolve into the solution and transform into ions. After the Sn ions deposit on the surface of Al-anode, the Ga ions will deposit on Sn. The higher activation of the polynary alloy anode is caused by much more new activated points composed of Ga-Sn alloy being continually formed. Ga- Sn alloy with low melting point deposited on …

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A New Method For Impregnating Nafion Solution Into The Electrode Of Pemfc, Qian Tang, Ming Han, Bao-Lian Yi, Zhi-Yin Lin Aug 2001

A New Method For Impregnating Nafion Solution Into The Electrode Of Pemfc, Qian Tang, Ming Han, Bao-Lian Yi, Zhi-Yin Lin

Journal of Electrochemistry

We have developed a new method for impregnating Nafion solution into the catalyst layer of homemade hydrophobic electrode using capillary process. Those electrodes show better performance and higher utilization of catalyst (detected by CV and TEM) than traditional spray method in PEMFC. According to the results of SEM photograph and linear-analysis of sulfur and platinum for the electrode cross-section, we can conclude that the resin is uniform in the catalyst layer and has almost same depth as catalyst in the impregnated electrode. While in traditional method resin is not uniform in the catalyst layer and penetrates into the diffusion layer, …

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The Coulostatic Method For Evaluating Corrosion In Reinforced Concrete, Yong-Tao Zhao, Jian-Hua Wu, Chang-Jiu Zhao Aug 2001

The Coulostatic Method For Evaluating Corrosion In Reinforced Concrete, Yong-Tao Zhao, Jian-Hua Wu, Chang-Jiu Zhao

Journal of Electrochemistry

In the present paper, the application of the coulostatic method to the corrosion of steel in concrete was reviewed. By comparing with other electrochemical techniques, the results obtained in the previous work reveal that the coulostatic method is an interesting alternative to the usual procedures for estimation of corrosion rate, and is better than them in some respects. The main advantages are as follows. The signal to be used can be instantaneous and as small as desired, so the electrode is minimally perturted during the measuring process. In addition, it is as rapid and quantitative, and at least as reliable …

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Characterization And Electrochemical Investigation Of Boron-Doped Mesocarbon Microbeads Anode Materials For Lithium-Ion Battery, Mao-Hui Chen, Guo-Tao Wu, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin Aug 2001

Characterization And Electrochemical Investigation Of Boron-Doped Mesocarbon Microbeads Anode Materials For Lithium-Ion Battery, Mao-Hui Chen, Guo-Tao Wu, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

The anodic performances of boron doped and undoped mesocarbon microbeads(MCMBs) were comparatively studied and the structures were characterized by XPS, SEM, XRD and electrochemical measurements. It was found that boron doping samples greatly increased the degree of graphitization and the crystallite size, leading to quite different morphology. Electrochemical discharge/charge cycle tests indicate that lithium intercalation occurred at a little higher potential for the boron doped MCMBs, being attended by greater irreversible capacity loss.

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Microstructure And Electrochemical Properties Of The Melt-Spinning Zr0.9Ti0.1(Ni, Co, Mn, V)2.1 Alloy, Ming-Fen Wen, Yu-Chun Zhai, Lian Chen, Min Tong, Hua Zhen, Rong-Jun Ma Aug 2001

Microstructure And Electrochemical Properties Of The Melt-Spinning Zr0.9Ti0.1(Ni, Co, Mn, V)2.1 Alloy, Ming-Fen Wen, Yu-Chun Zhai, Lian Chen, Min Tong, Hua Zhen, Rong-Jun Ma

Journal of Electrochemistry

The microstructure and electrochemical properties of Zr0.9Ti0.1(Ni,Co,Mn,V)2.1 alloys prepared by both the melt-spinning method and the conventional induction melting were investigated. XRD studies show that Zr0.9Ti 0.1(Ni,Co,Mn,V)2.1 alloys at as-cast, melt-spinning and annealing are all face center cubic structure with C15 laves phase, the higher the melt-spinning rate, the more the amorphous content. The electrochemical measurements show that melt-spinning alloys have better active behavior, low discharge capacity (< 280 mAh/g); but after annealed, the alloys are activated completely with 30 cycles, the capacities about 340 mAh/g are higher than those of as-cast and melt-spinning alloys; the annealec alloys have a better cycle stability than that of as-cast alloy, and the higher the melt-spinning rate is, the more stable the alloy becomes; at 300 mAh/g current density, the capacity of annealed 40 m/s alloy is up to 85% of the maximum capacity after 800 cycles, the capacity decay rate is about 6.9%.

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Charge/Discharge Characteristics And Structural Changing Of Spherical β-Ni(Oh)2 Prepared From Different Nickel Salt, Shu-Ting Yang, Yan-Hong Yin, Hong-Jun Chen, Jun-Hua Jia, Ming-Chum Zhang, Li Ding Aug 2001

Charge/Discharge Characteristics And Structural Changing Of Spherical β-Ni(Oh)2 Prepared From Different Nickel Salt, Shu-Ting Yang, Yan-Hong Yin, Hong-Jun Chen, Jun-Hua Jia, Ming-Chum Zhang, Li Ding

Journal of Electrochemistry

Spherical β-Ni(OH)2 was prepared from different nickel salt by homogeneous complexing precipitation method. Its charge/discharge and cyclic voltammetry properties were studied. The authors found that there are many differences in the electrochemical properties of the prepared Ni(OH)2.The specific capacity, cycling life and the discharging plateau of the material prepared from NiSO4 were superior to those of the material prepared from Ni(NO3)2. The reasons of the differences were analyzed by XRD and FTIR measurements, which will become abasis for the selection of raw materials.

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In Situ Ftir Reflection Spectroscopy Of Bioelectrode, Sa-Ying Dong, Guang-Yu Zhao, Yuzhu Gao, Guang-Zhang Chen, Ming-Xiang Lv Aug 2001

In Situ Ftir Reflection Spectroscopy Of Bioelectrode, Sa-Ying Dong, Guang-Yu Zhao, Yuzhu Gao, Guang-Zhang Chen, Ming-Xiang Lv

Journal of Electrochemistry

In situ FTIR reflection spectroscopy was used to study mediated enzyme electrode and immunoelectrode. We determined and analyzed IR characteristic spectra of GOD and glucose by the use of potential difference spectra and single beam subtractive spectra. At last, we explored the IR absorption characters of enzyme-immunoelectrode.

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The Influence Of Membrane Resistance On The Electrochemical Behavior Of Gold Electrode Modified By Self-Assembled Monolayer, Xiao-Li Cui, Zhi-Yu Jiang Aug 2001

The Influence Of Membrane Resistance On The Electrochemical Behavior Of Gold Electrode Modified By Self-Assembled Monolayer, Xiao-Li Cui, Zhi-Yu Jiang

Journal of Electrochemistry

The electrochemical behavior of gold electrode modified by hexadecanethiol self-assembled monolayer (SAM) in the solution of Fe(CN)63-/Fe(CN)64- was investigated by cyclic voltammetry and ac impedance spectroscopy. The pinhole-free SAM-modified gold electrode has excellent blocking properties to the interfacial electron transfer from redox couple in solution to the substrate. The current increased exponentially with the overpotential at the high potential region. A good linear relationship between ln(I/η) and η1/2 was observed. A model system Au/SAM/Hg was constructed and its I～V curve was measured. Similar phenomena were observed. There was also a linear relationship between ln(I/V) …

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Codeposition And Corrosion Resistance Of Nickel-Cerium-Phosphorus Amorphous Alloys, Jiang Liu, Xiong Jiang, Lin-Cai Jiang, Ze-Shan Zhu Aug 2001

Codeposition And Corrosion Resistance Of Nickel-Cerium-Phosphorus Amorphous Alloys, Jiang Liu, Xiong Jiang, Lin-Cai Jiang, Ze-Shan Zhu

Journal of Electrochemistry

The possibility of electrodeposition of rare earth alloys from aqueous bath was investigated using varous techniques such as linear potential sweeping, cyclic voltammetry, electrodepositon at constant potential etc. The Ni-Ce-P alloys with different cerium content were electrodeposited from a weakly acidic solution containing CeCl3, NaH2PO2 and so on the crystal structure and component were characterized by XPS, AES, XRD and SEM observation. The codeposits were found to be more highly corrosion resistent than that of Ni-P amorphous alloys by measuring polarization resistance and corrosion potential. The effects of codeposition conditions on the corrosion resistance were …

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Determination Of Hydrogen Diffusion Coefficient In Metal Hydride Electrode With Electrochemical Impedance Spectroscopy, Xian-Xia Yuan, Nai-Xin Xu Aug 2001

Determination Of Hydrogen Diffusion Coefficient In Metal Hydride Electrode With Electrochemical Impedance Spectroscopy, Xian-Xia Yuan, Nai-Xin Xu

Journal of Electrochemistry

Electrochemical impedance spectroscopy was employed to determine the hydrogen diffusion coefficient in MlNi 3.75Co 0.65 Mn0.4Al0.2 metal hydride electrode with various states of charge (SOC) at room temperature and with 50% SOC at various temperatures. It was found that hydrogen diffusion coefficient in this electrode decreases with the increase in SOC at ambient temperature, and for the electrode with 50% SOC, hydrogen diffusion coefficient increases with the increase of temperature and the activation energy for hydrogen diffusion in it is 35 kJ/mol.

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Delamination Resistant Composites Prepared By Small Diameter Fiber Reinforcement At Ply Interfaces, Youris A. Dzenis, Darrell H. Reneker Jul 2001

Delamination Resistant Composites Prepared By Small Diameter Fiber Reinforcement At Ply Interfaces, Youris A. Dzenis, Darrell H. Reneker

Department of Mechanical and Materials Engineering: Faculty Publications

A fiber reinforced composite material comprising a resin matrix and primary reinforcement fibers and further comprising secondary, smaller diameter, reinforcement fibers at one or more ply interfaces, or portion thereof, provides improved interlaminar toughness, strength, and delamination resistance and without substantial increase in weight. In one embodiment, the small fibers are attached to one side of a conventional prepreg prior to lamination. The small fibers are flexible and are expected to conform to the shape and distribution of the primary reinforcing fibers at the interface.

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Energy Absorbing Breakaway Steel Guardrail Post, John R. Rohde, John D. Reid, Dean L. Sicking Jul 2001

Energy Absorbing Breakaway Steel Guardrail Post, John R. Rohde, John D. Reid, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

An improved breakaway steel guardrail post for use in dissipation of impact energy upon impact of the post having an upper post member and a lower post member, a connecting joint, and a mechanism connected to the upper and lower post members for controlling the energy dissipation of the guardrail post about the connecting joint at a predetermined rate. A first embodiment utilizes a cable restraint lopped through openings in he guardrail posts. Other embodiments included straps and fasteners disigned to distort or fail at predetermined rates or strengths and combinations thereof.

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