Engineering Commons^™

Theory Of Cyclic Voltammetry At Microdisk Electrode For Reversible Systems, Qiankun Zhuang, Hongyuan Chen

Journal of Electrochemistry

By means of a new approach, the current equations of cyclic voltammetry which describes two cases of quasi-steady-state and fast linear scan at microdisk electrode for reversiblesystem were presented and verified experimentally. It has been shown that the features of this currentessentially depend on the ration of, which is described in detail. ln extreme cases, the equationsare the same as those listed in literatures for large plane and spherical electrodes. Using the quasi-steady-state equation, the causes and conditions for forming steady state, quasi-steady state andhysteresis current for linear sweep voltammetry are all explained and discussed. The width of the ″hysteresis …

A Relativistic Density-Functional Investigation Of Vibrational Frequencies Of Cn- On Cu And Ag Electrodes, Mengsheng Liao, Xin Lv, Qianer Zhang

Journal of Electrochemistry

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Studies On The Structure Of Licoo2 Synthesized With Tartaric Acid And The Behaviorof Its Rechargeable Lithium Battery, Fuping Zhang

Journal of Electrochemistry

The structure of LiCoO₂ synthesized with tartaric acid and the behavior of itsrechargeable Lithium battery have been studied by XRD, XPS, CV, CT. It has been shown that LiCoO₂ has a space group R3m with hexagonal parameters a=0.2810 nm, c=1.4088 nm. Low-spin state Co³⁺ configuration in LiCoO₂ has been suggested. Also, Li₂O, was identified onits surface. Furthermore, the capacity and the middle working voltage of its Lithium battery are about 120 mA·h·g^-1 and 3.8 V, respectively. The EMF of the cell changes with the Lithium composition of itscathode following E=4.318-0.450 X^2/3 in …

Studies On The Bright Zinc-Nickel Alloy Palting In Alkaline Baths, Jiale Cai, Shaomin Zhou

Journal of Electrochemistry

The electrochemical properties of the Zn-Ni plating baths and the structure andperformance of the obtained deposits were investigated. The results show that the nickel content of theobtained deposits is incereased with decreasing of Zn²⁺/Ni²⁺ ratio in the baths and with increasing of cathodic current density; The cathode current efficiency is increased with increasing of Zn[Ⅱ] content in the bath and with decreasing of cathodic current density. The ZN-11 additive used is thereaction product of heterocyclic compound and polyamines with epichlorohydrin, it has a higheradsorptivity on Hg-electrode at potential between -0.16～-1.68 V (vs. Hg/HgO, 1 mol·L^-1 KOH). …

Design Of A Structured Light Sensor For In Situ Calibration, Fred W. Depiero, Reid L. Kress

Electrical Engineering

This paper highlights a ranging sensor that can be calibrated at standoffs of 1 to 3 feet with a depth of field of ≈ 1 ft. Tests at a 16" standoff have produced a 0.004 inch standard deviation in height measurement errors. The data density and field of view are programmable. The sensor is positioned robotically, allowing it to provide accurate, short-range measurements prior to manipulation tasks. The sensor head is relatively inexpensive (≈ $10k) and is designed for in situ calibration. This approach is intended to allow replacement components to be installed, calibrated, and validated without decontamination. Calibration, validation …

Nonlinear Geometric And Material Behavior Of Composite Shells With Large Strains, Scott A. Schimmels

Theses and Dissertations

A two-dimensional, geometrically and materially nonlinear shell theory applicable to arbitrary geometries described by orthogonal curvilinear coordinates and encompassing large displacements, moderate rotations for large strain situations has been developed. Additionally, the theory includes Jacobian transformation matrices, based upon displacement parameters, for the Cauchy - 2nd Piola-Kirchhoff stress-state and the Cauchy (Almansi) - Green strain-state transformations, and a layered material approach is included for the elastoplastic analysis to allow for variation of plasticity through-the-thickness. Doubly curved 20, 28, and 36 degree-of-freedom finite elements are defined based on specialization of the theory to spherical coordinates. The computer program includes algorithms for …

Estimation Of Internal Forces And Moments In Linearly Vibrating Beam Structures, Doris Yasmou Yacoub

Archived Theses and Dissertations

No abstract provided.

Method Of Making Quasicrystal Alloy Powder, Protectivecoatings And Articles, Jeffrey E. Shield, Alan I. Goldman, Iver E. Anderson, Timothy W. Ellis, R. William Mccallum, Daniel J. Sordelet

Department of Mechanical and Materials Engineering: Faculty Publications

A method of making quasicrystalline alloy particulates wherein an alloy is superheated and the meltis atomized to form generally spherical alloy particulates free of mechanical fracture and exhibiting a predominantly quasicrystalline in the atomized condition structure. The particulates can be plasma sprayed to form a coating or consolidated to form an article of manufacture.

Electrochcmical Reaction Of Redox Proteins Speeded Up By The Dye Modified Electrodes, Ting Chen, Shaojun Dong, Yuanwu Xie

Journal of Electrochemistry

The electron transfer reaction of redox proteins faciliated by dye medifiedelectrode was reviewed in this paper. The medification metheds and the properties of dye modifiedelectrode were discussed. Several different studying metheds,such as voltammetry, flow analysis and spectroelectrochemical method, were reviewed. Areversible electrocatalytic reaction mechanism was proposed and verified by comparing the digital calculation results with the experimental results.

Photoelectrochemical And Spectroelectrochemical Studies Oniron Oxide Ultrafine Particles, Maizhi Yang, Yongjun Ji, Wen Zhang, Shengmin Cai, Xiaojiang Lu, Zhongqun Tian, Jin Luo

Journal of Electrochemistry

In this paper, Raman spectra, photocurrent and the UV-VIS reflectance aremeasured for studying the α-Fe₂O₃ ultrafine particles adsorbed on Pt electrode. The blue shifts of Raman peaks demonstrate the size quantization effect for the particles of 50 nm in diameter ascompared with the bulk material. With the changing of the potential, the photocurrent decrcases as the UV-VIS reflectance increases, and vice-versa. Therefore, the potential not only affects the hargetransfer direcdtion in the interface of electrode/redox couple, but also influences the light absortion onthe surface of particles. According to the results of photoelectrochemistry, we suggest that the cathodic …

Laser Scanning In-Situ Photoelectrochemical Microscopictechnique And Its Applications, Zugeng Lin, Jinkua You, Xiangdong Zhuo, Chun Zhang, Yong Yang

Journal of Electrochemistry

The main factors of the laser scanning in-situ photoelectrochemical microscopic measurement system which is set up in our lab have been discusaed in this paper. Some applications of this technique for in-situ study of modification and processing of semiconductor electrodes, monitoring of electro deposition process of semiconducting material and redox reaction occurring at metal oxide electrodes have also been presented. The results have shown that the technique is very powerful that for studing local photoelectrochemical properties of semiconductors and metal oxide electrodes. These provide important information on the micro structural and electronic properties in the solid/electrolyte interface.

Horseradish Peroxidase/Poly-O-Phen Ylenediamine Mem Brane Electrode: Preparation And Properties, Dong Wei, Huihuang Wu

Journal of Electrochemistry

A horseradish peroxidase (HRP)/poly-o-phenylenediamine (PPD) membrane electrode was prepared by electropolymerization of o-phenylenediamine on glassy carbon in pH 7.0 phosphate buffer, the process of the enzyme immobilization was studied. The enzyme electrode obtained exhibits the activity to catalyze the electroreduction of hydrogen peroxide in the absence of any electron transfer mediator. The red uction reaction occurs in the potential range of PPD redoxprocess, it was believed that the polymer participates in electron transfer of the enzyme. The enzyme reaction kinetics at rotating HRP/PPD electrode was analysed, and the factors influencing kinetic parameters were discussed.

Studies On Low Temperature Performance Of Rechargeable Mh-Ni Batteries, Wenkuan Zhang, Jingxian Shi, Yuwan Lou, Qiusheng Duan

Journal of Electrochemistry

The Dependence of low temperature performance on the alloy composition and electrolyte component for rechargeable MH-Ni batteries is studied, the suitable composition of alloy and electrofyte are founds.

An Indirect Electrochemical Oxidation Of Toluene──Anodic Oxidation Of Mn(Ⅱ) On The Lead Electrode, Zhonghua Wang, Qingmin Hua, Guacai Chen, Zhongquan Wang, Yunan Qiu, Xingguo Yan

Journal of Electrochemistry

The electrochemical oxidation of Mn(Ⅱ) to Mn(Ⅱ) in concentrated H₂SO₄ (2 ~ 8 mol⋅L^-1) at lead electrode has been studied. It is found that the electrode surface is oxidized to PbO₂ in a direct electrochemical reaction, then PbO₂ formed reacts with Mn(Ⅱ) in a chemical reaction. Some effects involves current density, concentration of H₂SO₄, temperature and conversionwere evaluated. The rule of electrogenerated Mn(Ⅲ) in flow electrolysis cell were determined at several conditions. The current efficiency at greater than 90% is obtained in general.

Electrochemically Modified Glassy Carbon Electrode And Determination Of Copper By Anodic Stripping Voltammetry, Jinrui Xu, Yie Liu, Xiurun Zhuang, Tomoo Miwa, Toyohide Takeuchi

Journal of Electrochemistry

This paper reported the glassy carbon electrode modified by cyclic voltammetrybetween -0.1 and +1.5 V (vs. SCE) in an aqueous solution containing catechol, for maldehyde and talium hydroxide. The modified electrode can be applied to the determination of copper(Ⅱ) in water, and its sensitivity is about 35 times higher than that of unmedified glassy carbon electrode, The quantitative limit with this modified electrode is 0.1 ng/ml.

The Reduction Of Oxygen To Hydrogen Peroxide At The Poly(O-Phenylenediamine)-Filmed Electrode, Zhaoe Lu, Tiangeng Zhong, Guanyong Zhang

Journal of Electrochemistry

The poly(o-phenylenediamine) (PPD) filmed graphite electrode was formed by electro-polymerization of o-phenylenediamine in acidified (pH=1) 0.2 mol·L^-1 Na₂SO₄ solution using the cyclic voltammetric methed. The catalytic effect of the electrcareduction of oxygen in acid olution was demonstrated by the voltammogram of the electrode in the oxygen saturated acid solutionof Na₂SO₄. The current efficiency of the reduction of oxygen to hydrogen peroxide was determined by the electrolysis in a divided cell under the condition of constant current. The various effectsinfluencing the accmulation of H₂O₂ in the catholyte were discussed.

Studies On Coordination Behavior Of Dimethyl Sulfoxide In Complex Of Rare Earth With Cryptand, Shichang Liu, Tianpei Zhu

Journal of Electrochemistry

Electrochemical reduction reaction in the course of the titration of Eu(2.2.2) and Eu(2.2) using strong bonding solvent, DMSO, in C₂H₄Cl₂ has been investigated by cyclic voltammetry. The greater the concentration of strong bonding solvent, the more negative the half-wave potentials for the reduction reaction are. The coordination number of Eu(2.2.2) and Eu(2.2) which are 2 and 3 respectively, with DMSO can be calculated, according to the relations between half-wave potentials and the variety of concentration of DMSO.

The Electrochemical Reduction Of 2-Ethylanthraquinone (2eaq), Yaobin Zhu

Journal of Electrochemistry

The process of electrochemical reduction of 2EAQ in DMSO is studied using CVand ESR methods in this work, Pt, Pd and some implanted materials are used as electrodes. The quasi-rever-sible property of two electron transfer steps and their following homogeneous chemical reactions are illustrated. The mechanism of the electrochemical red uction of 2EAQ and the kinetic parameters of the related steps are obtained. Having measured the influence of water content in the system, the effect of the proton donor is discussed. After comparising the experimental results with each other these experiments gives us the idea that the replacement of metal …

Distortion And Evolution Of A Localized Vortex In An Irrotational Flow, Joseph F. Lingevitch, Andrew J. Bernoff

All HMC Faculty Publications and Research

This paper examines the interaction of an axisymmetric vortex monopole, such as a Lamb vortex, with a background irrotational flow. At leading order, the monopole is advected with the background flow velocity at the center of vorticity. However, inhomogeneities of the flow will cause the monopole to distort. It is shown that a shear‐diffusion mechanism, familiar from the study of mixing of passive scalars, plays an important role in the evolution of the vorticity distribution. Through this mechanism, nonaxisymmetric vorticity perturbations which do not shift the center of vorticity are homogenized along streamlines on a Re1/3 time scale, much faster …

An Investigation Of Hole Size Effects In A Composite Material During Tensile Fracture, David Floyd Moore

Mechanical & Aerospace Engineering Theses & Dissertations

An experimental investigation was conducted to evaluate the hole size effects, i.e., the reduction in strength with an increase in hole size at a constant stress concentration factor, for a glass fiber reinforced epoxy crossply laminate during tensile fracture. The characteristic dimension according to the point-stress and average-stress criteria of the two-parameter models proposed by Whitney and Nuismer were determined and compared for a circular hole, optimized circular hole, square hole with radiused corners and square hole with sharp corners. Modified versions of the two-parameter models proposed by Karlak and Pipes, Wetherhold, and Gillespie were also compared. On the basis …

Automatic Differentiation For First- And Second-Order Sensitivity Derivatives Of A Cfd Code, Laura Lee Sherman

Mechanical & Aerospace Engineering Theses & Dissertations

The straightforward automatic-differentiation and the hand-differentiated incremental iterative methods are interwoven to produce a hybrid scheme that captures some of the strengths of each strategy. With this compromise, discrete aerodynamic sensitivity derivatives are calculated with the efficient incremental iterative solution algorithm of the original flow code. Moreover, the principal advantage of automatic differentiation is retained (i.e., all complicated source code for the derivative calculations is constructed quickly with accuracy). The basic equations for second-order sensitivity derivatives are presented; four methods are compared. Each scheme requires that large systems are solved first for the first-order derivatives and, in all but one …

Modeling And Simulation Of Load Introduction For Fuselage Crown Panel Testing, Kevin P. Belack

Mechanical & Aerospace Engineering Theses & Dissertations

This paper discusses the mechanism and behavior of load introduction to internally pressurized fuselage crown panels. Emphasis is placed on the finite element modeling of a simulated pressure-box test machine and representative fuselage crown panel. The geometry and mesh requirements for the finite element model are examined through numerical studies which gradually increase in complexity. These numerical studies culminate in the detailed specification of boundary conditions, mesh densities, load introduction mechanisms, element choice and solution process for the simulation of a pressure-box test machine and test panel.

The results obtained using the finite element model are then compared with experimental …

Studies Of Elecctrochcmical Oscillation Of Au/Hcl In Presence Of ″Positive Feedback″Of Substrate Electrodes, Bin Ren, Bingwei Mao, Xiongwei Cai, Tao Jiang, Jiqian Mu

Journal of Electrochemistry

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Transient Photocurrent Behavior Of Multiple Quantum Well Gaas/AlXGa(1-X)As Electrode, Liu Yao, Xurui Xiao, Yuan Lin, Yiping Zeng, Dianzhao Sun, Haiqun Zheng

Journal of Electrochemistry

Transient photocurrents induced by short light pulses at lattice-matched multiplequantum well (MQW)GaAs/Al_0.3)Ga_0.7 As electrodes were studied in the 1 ×10^-2 mol·dm^-3 ferrocene([Fc⁰]/[Fc⁺]=9/1)-0.1 mol·dm^-3 tetrabutylammonium tetrafluoroborate acetonitrile solutionin order to examine the relaxation photoprocesses and to evaluate kinetic parameters of superlattice electrodes.

GaAs/Al_0.3Ca_0.7 As MQW electrode consisting of 10 periods with each of GaAs well (5.3 nm) and Al_0.3Ga_0.7. As barrier (10 nm) showed two pronounced and well-resolved peak structures located at 1.503 eV and 1.699 eV in the photocurrent spectrum, corresponding to the …

Self Assembly Via Layer By Layer Surface Reaction On Gold Electrodes And The Electrochcmical Characterization, Xiandui Dong, Juntao Lu, Chuanxin Cha

Journal of Electrochemistry

The self-assembled monolayers,which were built by spontaneous adsorption of ω-carboxylic acid thiols on gold surface,were used as substrate for further modification through later bylayer amide surface reactions. At each stage of modification,the gold surface was characterizedelectochemieally. The results demonstrated that the strategies of layer by layer self assembly is ofsignificant potential for fabrieating functionalized ultrathin layers.

A Photoelectrochemical Investigation Of Zirconium Oxide Film, Maizhi Yang, Ping Wei, Di Quarto F., Piazza S., Sunseri C.

Journal of Electrochemistry

A photoelectrochemical investigation has been carried out on zirconium initialoxide film and its oxide film grownanodically at constant rate up to different thickness. Both anodicand cathedic photocurrents on the photocurrent spectrum depended on the potential, but had littlerelation with the forming anedic films or measuring solutions. Photocurrent spectrum and photocurrenttransients suggested that the oxide films on zirconium were duplex layers structure. The internal layerwas ZrO₂ and the external layer ZrO₂·(H₂O)_n. The photocurrent included photogenerated carrier ininternal and external oxide films, as well as internal photoinjection process for electrons from thesubstrate metal into the …

Electroreduction Of The Nittobenzene On Titanium Electrode Implanted With Palladium, Zhongda Wu, Xianjun Zhu, Hongsen Wang

Journal of Electrochemistry

The titanium substrates were bombarded with 1×10¹⁷～5×10¹⁷ ions·cm^-2 ofpalladium at the room temperature. The surface composition of implanted electrode and concentration-depth profiles of various elements were measured by AES. The electrored uction processes ofnitrobenzene (NB) in 0.1 mol/L NaOH solution at Pd/Ti electrodes have been investigated by cyclicvoltaivimetry. The results show that the palladium implanted titanium electrodes exhibit a high catalyticactivity in the electroreduction of NB. The NB radical anion, which is the product of one-electronelectroreduction of NB, was detected by ESR in-situ in conjunction with electrochemical methods. Aniline was also detected as a product of …

Electroreduction Of Holmium Ion On Iron Electrde In Molten Cholorides, Qiqin Yang, Guankun Liu, Yuzhi Su

Journal of Electrochemistry

The cyclic voltammetry, open circuit potential-time curve after poteritiostatic electrolysis, current-time curve at potential step, X-ray diffraction and electron probe microanalysiswere used to investigate the electrode process of Ho(Ⅲ) reduced on iron electrode in molten chloridesand the phases of surface alloy layer. The Ho-Fe alloys are formed at first, and then the metallic holmium is deposited when Ho(Ⅲ) is reduced on iron electrode. The charge transfer is reversible. The free energies of formation for the four inter metallic compounds of Ho-Fe system, the diffusion coefficients and diffusion activation energy of Ho in alloyed cathode are determined.

The Study Of The Growth Processes Of The Oxides On Lead Electrodes In Sulfuric Acid Solution, Hesheng Zhai, Xuguang Chen, Jinkua You, Yong Yang, Zugeng Lin

Journal of Electrochemistry

The growth processes of PbO and PbO₂ on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique and in-situ laser scanning photoelectrochemical microscopy. It is found that a linear relationship existsbetween the electrode resistance(R) and^1/2 after the electrode is oxidized at +0.6 V(vs.Hg/H₂SO₄/35% H₂SO₄) for more than 5 min. This result suggests that the growth of PbO is well distributed during the early stage of oxidation. The study by using laser scanning photoelectrochemical microscopy has further proved this point. The results also …

Application Of Inhibitor To Improve The Anticorrosion Performance Of Electrophoretic Coating, Changshou Cai, Fangteng Su, Bihuan Liu, Guomou Wen, Jingdong Guo, Renxin Liu, Weidong Tian

Journal of Electrochemistry

To improve the anti-corrosion performance of electrocoating, organic andinorganic inhibitors are applied in an anodic electrophoretic-coating. The results show that the deposition of polymer with zinc phospate exhibits a high inbihition efficiency. The inhibition mechanism of the inhibitor in electrocoating has been studied.