Physical Sciences and Mathematics Commons^™

Problems On The Study Of Anodic Films On Pb In Sulfuric Acid Solution(Ⅰ), Wenbin Cai, Houtian Liu, Weifang Zhou

Journal of Electrochemistry

The identification of the phase composition of the anodic film on Pb formed inH_2SO_4 solution in PbO potential region has long been argued,together with the explanation of thecathodic peak at about -0.9V(Hg/Hg_2SO_4)in the linear sweep voltammogram for a Pb-H_2SO_4system. In this article, a review of our recent investigations was presented on the above problems.

Progress In R&D Of Lithium Rechargeable Batteries In China, Jiqiang Wang

Journal of Electrochemistry

No abstract provided.

The Photoelectrochemical Studies Of Passive Films On Rebar Electrodes In Simulated Cement Pore Solution, Wei Chu, Yuanxiang Shi, Baoming Wei

Journal of Electrochemistry

The electronic properties of the passive film on REBAR electrodes in simulatedcement pore solution(pH=9.0～13.8)have been investigated using in-situ photoelectrochemicalmethods.The results show that the passive film is composed of mixed oxides of ferrum ,and it is anamorphous,n-type semiconductive film. Variations of pH values,ions in the solution and film-formation potentials can affect the composition of the films. There are two main stages in the growthof the film,with two rate functions characterized by linear relation between the film thickness and thelogarithm of time.The addition of inhibitor NaNO_2 changes the composition,structure and growthkinetics of the film,and therefore improves the resistance of pitting corrosion induced …

Studies On The Structure Of Licoo_2 Synthesized With Tartaric Acid And The Behaviorof Its Rechargeable Lithium Battery, Fuping Zhang

Journal of Electrochemistry

The structure of LiCoO_2 synthesized with tartaric acid and the behavior of itsrechargeable Lithium battery have been studied by XRD, XPS, CV. CT. It has been shown thatLiCoO_2 has a space group R3m with hexagonal parameters a=0.281 0 nm,c=1.408 8 nm. Low-spin state Co￣(3+) configuration in LiCoO_2 has been suggested. Also,Li_2O, 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 0.451≤X≤0.934.

The Oxidation Of Hydrogen Absotbing Alloys And Its Inhibition, Suqin Wang, Baojia Xia, Geping Yin, Pengfei Shi

Journal of Electrochemistry

This paper introduces the method to judge:1)the possibility of oxidation of themetal hydride electrode in an anode process by cyclic voltammetric curves,2)the oxidation pattern ofmetal hydride electrode in oxygen atmosphere in various charged states,and 3)the inhibition ofoxidation of hydrogen absorbing alloys by certain surface treatment.

Study On The Surface States Of Zinc Sulfide Thin Film Doped With Erbium And Their Effect On The Relaxation Luminance, Yujiang Wang, Zhaohong Liu, Zhenxiang Chen

Journal of Electrochemistry

X-ray photoelectron spectrum and characteristics of the capacity,versus thevoltage of the thin film devices are measured to study the surface states of the zinc sulfide thin film.The transient electroluminescence excited by pulses shows the relaxation luminance peaks during anon-exponential decay process of the characteristic transitions activated by Er￣(3+) in the ZnS directcurrent thin film electroluminescence (DCTFEL) devices.The surface structures of ZnS:Cu,Cl,Erfilm with the absorption of oxygen,and the effect of the surface states on the relaxation luminance ofthe devices are discussed.

Single-Layer-Coated Surfaces With Linearized Reflectance Versus Angle Of Incidence: Application To Passive And Active Silicon Rotation Sensors, R. M.A. Azzam, M. M. K. Howlader, T. Y. Georgiou

Electrical Engineering Faculty Publications

A transparent or absorbing substrate can be coated with a transparent thin film to produce a linear reflectanceversus- angle-of-incidence response over a certain range of angles. Linearization at and near normal incidence is a special case that leads to a maximally flat response for p-polarized, s-polarized, or unpolarized light. For midrange and high-range linearization with moderate and high slopes, respectively, the best results are obtained when the incident light is s polarized. Application to a Si substrate that is coated with a SiO₂ film leads to novel passive and active reflection rotation sensors. Experimental results and an error analysis …

Transient Wave Mixing And Recording Kinetics In Photorefractive Barium Titanate: A Nonlinear Coupled Mode Approach, Partha P. Banerjee, John M. Jarem

Electrical and Computer Engineering Faculty Publications

By using rigorous coupled-wave diffraction theory along with a time-dependent nonlinear formulation, we analyze two- and multiplewave coupling and the grating kinetics in BaTi03 with different boundary interfaces. Efffects of electrostatic and optical anisotropy have been included in the analysis. Significant mode conversion to higher orders is observed only when the boundary interfaces are highly mismatched.

Guest Editorial: Special Section On Photorefractive Nonlinear Optics, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Hand in hand with experimental work in photorefractives, there is a lot of activity in modeling photorefractive materials and experimental observations in the open literature. This special section contains a paper by Banerjee and Jarem, who use a rigorous coupled wave theory to analyze two- and multiple-wave mixing photorefractive barium titanate, modeled through the Kukhtarev equations.

Broadband Dynamic, Holographically Self-Recorded, And Static Hexagonal Scattering Patterns In Photorefractive Knbo3:Fe, Nickolai Kukhtarev, Tatiana V. Kukhtareva, John Caulfield, Partha P. Banerjee, Hsueh-Ling Yu, Lambertus Hesselink

Electrical and Computer Engineering Faculty Publications

We have observed and explained three types of hexagon pattern formation in photo refractive crystal KNb03:Fe. These are:

• Dynamic (laser induced)
• Semipermanent (holographically stored)
• Permanent (induced by a static domain grid) over a wide wavelength range

Comparison Of Time-Domain Reflectometry Performance Factors For Several Dielectric Geometries: Theory And Experiments, S. V. Maheshwarla, R. Venkatasubramanian, Robert F. Boehm

Electrical & Computer Engineering Faculty Research

We propose three nontraditional dielectric geometries and present an experimental and theoretical analysis and comparison of time domain reflectometry (TDR) performances for them. The traditional geometry (the probes inserted in material of essentially infinite extent) is compared to three nontraditional geometries where the probes are affixed outside of a core sample, inside of a bore, or flat on the surface of a semi-infinite solid. Our derivation relates the velocity of electromagnetic wave propagation to the complex permittivities and permeabilities of the media and the geometry for the three nontraditional configurations. Experimental results for air, styrofoam, dry sand, wet sand of …

Ohmic Contact To Ion Implanted Gallium Arsenide Antimonide For Application To Indium Aluminum Arsenide-Gallium Arsenide Antimonide Heterostructure Insulated-Gate Field Effect Transistors, Kenneth G. Merkel Ii

Theses and Dissertations

The p-channel In_0.52Al_0.48As-GaAs_1-xSb_x heterostructure insulated-gate field effect transistor (p-HIGFET) is a candidate for complementary integrated circuits due to superior cutoff characteristics and low gate leakage current. Advancement of the In_0.52Al_0.48As-GaAs_1-xSb_x p-HIGFET requires improved source-drain design. Five main tasks were accomplished to achieve this goal. First, thermal limits of the In_0.52Al_0.48As-GaAs_0.51Sb_0.49 HIGFET were investigated. Second, the temperature dependence of band gap and impurity energies were determined for beryllium doped In_0.52Al_0.48. Third, high acceptor concentrations were obtained …

Comparison Of System Identification Techniques For The Dexterous Orbital Servicing System (Doss), Allan Terrence Morris

Electrical & Computer Engineering Theses & Dissertations

The major contribution of system identification is the development of analytical models of a system. Many identification techniques can adequately describe the input and output map. One of the challenges of these techniques is to correctly infer from the measured data the characteristics of the individual, contributing components producing a more accurate system model.

In this thesis linear, dynamic, multivariable state-space models for three joints of the Dexterous Orbital Servicing System (DOSS) are identified. DOSS is a representative space station manipulator at the NASA Langley Research Center. The dynamic models of the manipulator will first be estimated by applying nonparametric …

A Unified Topological Approach To Electromagnetic Environmental Effects Protection, George H. Baker, J. Philip Castillo, Edward F. Vance

George H Baker

The presentation recommends an approach for unifying electronic system protection designs for a wide spectrum of electromagnetic environments. A general electromagnetic topological construct is developed as the basis for a consistent shielding and terminal protection methodology. Spectral characteristics of multiple interfering electromagnetic sources, both internal and external, are described. Effects addressed include EMI/EMC, lightning, nuclear EMP, and RF weapons. Protection practices for individual effects are discussed and means for integrating these into a single protection topology.

Optimal Mixed-Norm Control Synthesis For Discrete-Time Linear Systems, David R. Jacques

Theses and Dissertations

A mixed-norm approach to control synthesis for discrete time linear systems is developed. Specifically, the problem of minimizing the H₂ norm of a transfer function, subject to a combination of ℓ₁ and-or H_∞ norm constraints on dissimilar but related transfer functions is considered. The uniqueness of the optimal solution is shown, and numerical methods for approximating the optimal solution to within arbitrary accuracy are developed. These methods generally result in high order compensators which can not be implemented in most practical applications. In response to this, a numerical method is developed which solves for suboptimal solutions of …

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

Journal of Electrochemistry

Abstract The main factors of the laser scanning in-situ photoelectrochemical microscopicmeasurement system which is set up in our lab have been discusaed in this paper. Some applications ofthis technique for insttn study of medificiition and processing of semiconductor electrodes , monitoringof electredeposition process of semiconducting material and redox reaction occurring at metal oxideelectrodes have aiso been presented. The results have shown that the technique is very powerfui thatfor studing local photoelectrochemical properties of semiconductors and metal oxide electredes. Theseprovide important information on the micro structural and electronic properties in the solidlelectrolyteinterface.AbstractLaser scanning, Local photocurrent spectroscopy, Photoelectrochemical,Semiconductor electode

An Indirect Electrochemical Oxidation Of Toluene──Anodic Oxidation Of Mn(Ⅱ) On The Lead Electrode, Zhonghua Wang, Qingmin Hua, Guaeai Chen

Journal of Electrochemistry

The electrochemical oxidation of Mn (Ⅱ) to Mn(Ⅱ) in concentrated H_2SO_4(2￣8 mol . L-1) at lead electrede has been studied. It is found that the electrede surface is oxidized toPbO_2 in a direct electrochemical reaction, then PbO_2formed reacts with Mn (Ⅱ) in a chemicalreaction. Some effects involves current density , concentration of H_2SO_4 , temperature and conversionwere evaluated. The rule of electrogenerated Mn (Ⅲ) in flow electrolysis cell were determined atseveral 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

Journal of Electrochemistry

This paper reported the glassy carbon electrode modified by cyclic voltammetrybetween-0. 1and + 1. 5 V(vs. SCE)in an aqueous solution containing catechol,formaldehyde andtalium 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 electrede, Thequantitative limit with this modified electrede is 0. 1 ng/ml.

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

Journal of Electrochemistry

lectrochemical reduction reaction in the course of the titration of Eu ( 2.2.2)and Eu( 2.2)using strong bonding solvent,DMSO,in C_2H_4Cl_2 has been investigated by cyclicvoltammetry. The greater the concen tration 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 betweenhalf -wave potentials and the variety of concentration of DMSO.

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)membraneelectrede was prepared by electropolymerization of o-phenylenediamine on glassy carbon in pH 7.0phosphate buffer,the process of the enzyme immobilization was studied,The enzyme electredeobtained exhibits the activity to catalyze the electrored uction of hydrogen peroxide in the absence ofany 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 enzymereaction kinetics at rotating H RP/PPD electrede was analysed,and the factors influencing kineticparameters were discussed.

Photoelectrochemical And Spectroelectrochemical Studies Oniron Oxide Ultrafine Particles, Maizhi Yang, Yongjun Ji, Wen Zhang, Shengmin Cai

Journal of Electrochemistry

in this paper, Raman spectra, photocurrent and the UV-VIS reflectance aremeasured for studying the α-Fe_2O_3ultrafine particles adsorbed on Pt electrode. The blue shifts ofRaman 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 theUV-VIS reflectance increases, and vice-versa. Therefore, the potential not only affects the hargetransfer direcdtion in the interface of electrede/redox couple, but also influences the light absortion onthe surface of particles.According to the results of photoelectrochemistry, we suggest that the cathedicphotocurrent in the potential range of more …

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

Journal of Electrochemistry

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

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. Thequasi-rever+sible property of two electron transfer steps and their following homogeneous chemicalreactions are illustrated,The mechanism of the electrochemical red uction of 2 EAQ and the kineticparameters of the related steps are obtained. Having measured the influence of water content in thesystem, the effect of the proton donor is discussed. After comparising the experimental results witheach other these experiments gives us the idea that the replacement of metal Pd or some Pd-catalystswith pd-implanted …

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 byelectro-polymerization of o-phenylenediamine in acidified(pH=1)0.2 mol·L-1 Na_2SO_4 solutionusing the cyclic voltammetric methed. The catalytic effect of the electrcareduction of oxygen in acidsolution was demonstrated by the voltammogram of the electrede in the oxygen saturated acid solutionof Na_2SO_4. The current efficiency of the reduction of oxygen to hydrogen peroxide was determined byIhe electrolysis in a divided cell under the condition of constant current. The various effectsinfluencing the accm ulation of H_2O_2 in the catholyte were discussed.

Bandwidth And Additive Bandwidth Of Graphs, Maria Kujawski

Honors Capstone Projects and Theses

No abstract provided.

Review: 'Integrated Optics: Design And Modeling,' By Reinhard Marz, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

My overall impression is that Integrated Optics: Design and Modeling will make a fine addition to almost anyone's collection of books on integrated optics. It will, however, serve its readers better as a reference book than as a text from which to first learn the basic concepts of integrated optics. I say this because the book is written at a fairly sophisticated technical level, though the author often moves rather quickly to the "bottom line" without providing material much beyond what is first necessary to introduce a problem or concept, and then a statement of the results and/or implications. It …

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 1×10￣(17)～5×10￣(17)ions·cm￣(-2) ofpalladium at the room temperature. The surface composition of implanted electrede 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 NB by using UV-spectra in-situ. According to the …

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 PbO_2 on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique andin-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/H_2SO_4/35%H_2SO_4)for more than 5 min.This result suggests that the growth of PbO is well distributedduring the early stage of oxidation.The study by using laser scanning photoelectrochemical microscopyhas further proved this point.The results also show that the growth of PbO_2 takes place and develops.

Electrocatalytic Oxidation Of Formaidehyde And Formic Acid On A Pt/Sb_(Ad) Electrode, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic activity for the oxidation of formaldehyde and formic acid ona Sb-modified platinum (Pt/Sb_(ad))was investigated.Results showed that the Pt/Sb_(ad) electrode waselectrocatalytically more active than a Pt electrode in the anodic oxidation of formaldehyde and formicacid.In the case of formaldehyde,an oxidation peak appeared at a potential of ca.0.7V.During theoxidation of formic acid,a 4-fold increase in the 1st peak current was observed.The Sb-modifiedplatinum electrode was found to be most electrocatalytically active at a coverage of 0.75±0.05.Theelectrocatalytic activity of the Pt/Sb_(ad) electrode can be best explained in terms of the geometrical effect,which may lead to the inhibition of the formation of the …

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 poteritiostaticelectrolysis,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 metallicholmium is deposited when Ho(Ⅲ)is reduced on iron electrede. The charge transfer is reversible. Thefree energies of formation for the four intermetallic compounds of Ho-Fe system,the diffusioncoefficients and diffusion activation energy of Ho in alloyed cathode are determined.