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The Electrostatic Interaction Of Charged, Dust-Particle Pairs In Plasmas, M. E. Markes, P. F. Williams

Department of Electrical and Computer Engineering: Faculty Publications

We report the results of a study of the electrostatic interaction between negatively charged particles in a plasma. The goal of the study was to investigate the possibility of an attractive interaction which would make possible the formation of “molecules” of particles. For all approximations relating the positive ion density to the local electrostatic potential that we examined, we find that the interaction is repulsive for all particle separations.

Qualitative Modeling For Magnetization Curve, Pei-Hwa Huang, Yu-Shuo Chang

Journal of Marine Science and Technology–Taiwan

This paper studies the derivation of a qualitative description for the magnetization curve of saturable magnetic materials. From a set of numerical input-output data, a fuzzy model, which is a collection of fuzzy IF-THEN rules for describing the studied system, is first constructed for the magnetization curve. A procedure consisting of a fuzzy clustering method and a rule processing algorithm is then employed for processing the constructed fuzzy modeling rules to extract the qualitative properties of the curve. The proposed approach is objective in that it can yield the system qualitative features without domain experts’ knowledge. An example is demonstrated …

Electrochemical Hydrogen Storage Properties Of Carbon Nanotubes, Xue Qin, Xue-Ping Gao, Feng Wu, Hong Liu, Ying Lan, Hua-Tang Yuan, De-Ying Song, Pan-Wen Shen

Journal of Electrochemistry

The electrochemical properties of carbon nanotubes (CNTs) electrode have been investigated in this paper. The high discharge capacity of 200 mAh·g^-1 was measured for the CNTs Ni electrode at a discharge density of 200 mAh·g^-1 . CNTs-Ni electrode, the high electrochemical activity and the long cycle life were observed. The electrochemical mechanism of hydrogen adsorption and oxidation at the CNTs Ni electrode was studied by cyclic voltammertry method.

Template Synthesis Of Nano-Structured Electrode Materials And Its Electrochemical Performance, Jian Zhao, Quan-Yong Gao, Yong Yang, Zu-Geng Lin

Journal of Electrochemistry

In this letter, various nano structured materials such as spinel LiMn₂O₄ nanotubes/nanowires and carbon nanotubes have been prepared by using porous alumina template. The prepared template and materials have been characterized by AFM and TEM techniques. It is shown that size of the nanotubes can be conveniently controlled by using template method. Some preliminary results of cyclic voltammetry about nano structured LiMn₂O₄ are also reported.

The Electrochemical Performance Of The Spinel Limn2O4, Shi-Gang Lu, Yu-Cheng Sun, Ren-Min Liu, Wei-Hua Jin, Wen-Zhong Li, Cang Han

Journal of Electrochemistry

The cathode material spinel LiMn₂O₄ of lithium ion battery was synthesized by making use of solid state reaction at 750～850 ℃. The discharge capacity was 115～125 mAh·g^-1 . It was observed that the capacity loss increase at the elvated 55 ℃ temperature. A little excess Li content and the Co doped spined could improved the cycle capability of the cathode material. The dissolution of the spined in the electrolyte was measured. The treatment method was used to stabilize the LiMn₂O₄ structure. It was found that the spinel LiMn₂O₄, treated …

The Memory Effect Of Mh-Ni Battery, De-Ming Xie, Jian-Ming Wang, Jian-Qing Zhang, Chu-Nan Cao

Journal of Electrochemistry

The memory effect of MH-Ni battery was investigated. The depth of discharge, discharge rate and cycle number influence the memory effect greatly. A few completely full charge/discharge cycles could eliminate it. The existence of the memory effect had nothing to do with zinc element. During the course of life cycling at low DOD (degree of discharge), the smaller the discharge current was, the lower was the maximum charge voltage. In addition, discharge voltage and discharge capacity drop fast at the beginning, gradually leveled off at about a value. If the discharge current was increased, the discharge capacity was obviously less …

Effect Of High Concentration Lithium Bromide Solution On Electrochemical Behavior Of Low Alloy Steel At High Temperature, Jian-Wei Guo, Cheng-Hao Liang

Journal of Electrochemistry

By electrochemical measurements and weight loss experiments, the effect of MoO₄^2- on low alloy steel's electrochemical behaviors was investigated at high temperature in 55%LiBr+0.07 mol/L LiOH solution. The results showed that MoO₄^2-, as an anodic inhibitor, formed passive film rapidly and impeded both anodic and cathodic procedures. Moreover, Na₂MoO₄ prevented corrosion effectively in 55%LiBr+0.07 mol/L LiOH solution when its concentration is more than 200 mg/L. The pitting potential increased accompanying to the arising of Na₂MoO₄ concentration. Some elements of alloy strengthened resistance to corrosion, shch as chromium and nickel, …

The Development Of Carbon Monoxide Tolerant Catalysts For Proton-Exchange Membrane Fuel Cell, Zhong-Jun Hou, Hong-Mei Yu, Bao-Lian Yi, Ming Han

Journal of Electrochemistry

High over-potential of proton exchange membrane fuel cell (PEMFC) anode caused by carbon monnoxide poisoning when reformate or methanol is used as fuel is main obstacle to the high performance of PEMFCs. Using carbon monoxide tolerant catalysts is the most hopeful way to solve the CO problem. The CO poisoning problem is reviewed briefly in this paper, and the development of CO tolerant catalysts is introduced in details, including electrocatalysts activity, preparation method and mechanism of tolerance to CO.Mo and W can improve catalysts' CO tolerance. Multi-component catalysts are expected to be more tolerant to CO.

Studies Of Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode——I. Cyclic Voltammograms And In-Situ Ftir Spectroscopy In Alkaline Media, Guo-Lian Chen, Shi-Gang Sun, Sheng-Pei Chen, Zhi-You Zhou

Journal of Electrochemistry

The electro-oxidation of ethanol on nm-Pt/GC electrode in alkaline solutions containing 0.02 mol·L^-1 NaOH+0.1 mol·L^-1 CH₃CH₂OH was investigated by using cyclic voltammetry and in-situ FTIR spectroscopy. The experimental results demonstrated that the main product of ethanol oxidation is CH₃COO^-, only very small amount of CH ³CHO has been determined simultaneously. In contrast with the dual path reaction mechanism for the oxidation of ethanol in acid media, the oxidation of ethanol in alkaline media didn't pass through the dissociative adsorption, and no adsorbed species could be determined even using a …

Investigation Of A Complex Lithium Cobalt Nickel Oxide As Lithium Ion Battery Cathode Materials Prepared By A New Citrate Sol-Gel Method, Jing-Li Han, Qing-Guo Liu

Journal of Electrochemistry

The synthesis and electrochemical characteristics of lithium cobalt nickel oxide as cathode materials for rechargeable lithium batteries were investigated. It was clarified from these investigations that lithium cobalt nickel oxide has been produced from basic cobalt carbonate,basic nickel carbonate, lithium carbonate, and citrate. LiNi_0.8Co _0.2O₂ prepared under the stream of oxygen gas showed a higher cycling capacity of (～190 mAh·g^-1).

Pd/Ni Metal-Oxide-Semiconductor Hydrogen Sensor Utilizing A Segregated Pd-Ti Adhesion Layer, Mark Wayne Jenkins

Electrical and Computer Engineering ETDs

A novel technique has been developed that incorporates an adhesion layer into a hydrogen sensor that is based on a MOS structure. Previous structures containing no adhesion layer exhibited long-term drift and device failure due to delamination of the gate. While devices that did incorporate a normal adhesion layer lost all of their sensitivity. This is the first demonstration of combining virtues of an adhesion layer for a noble metal on insulator while retaining hydrogen sensitivity in a field effect sensor. The design issues related to utilizing Pd films for hydrogen sensors are presented. The recipes for fabricating the sensors …

System Level Microwave Design: Radar-Based Laboratory Projects, Michael A. Jensen, David V. Arnold, Donald E. Crockett

Faculty Publications

Two laboratory projects-a Doppler radar and a synthetic aperture radar (SAR)-designed to augment traditional electromagnetics education are proposed. The projects introduce students to component and system level design and expose them to modern computer-aided design (CAD) tools, microstrip and surface mount fabrication technologies, and industry standard test equipment and procedures. Additionally, because the projects result in a working radar system, students gain new enthusiasm for the electromagnetics discipline and directly see its relevance in the engineering field. Implementation of these laboratories within the curriculum have proven to be highly motivational and educational and have even contributed to increased enrolments in …

Detection Of Solid Pigment In Dermatoscopy Images Using Texture Analysis, Murali Anantha, William V. Stoecker, Randy Hays Moss

Chemistry Faculty Research & Creative Works

Background/aims: Epiluminescence microscopy (ELM), also known as dermoscopy or dermatoscopy, is a non-invasive, in vivo technique, that permits visualization of features of pigmented melanocytic neoplasms that are not discernable by examination with the naked eye. ELM offers a completely new range of visual features. One such feature is the solid pigment, also called the blotchy pigment or dark structureless area. Our goal was to automatically detect this feature and determine whether its presence is useful in distinguishing benign from malignant pigmented lesions.

Methods: Here, a texture-based algorithm is developed for the detection of solid pigment. The factors d and a …

Dielectric Function Of Amorphous Tantalum Oxide From The Far Infrared To The Deep Ultraviolet Spectral Region Measured By Spectroscopic Ellipsometry, Eva Franke, C. L. Trimble, M. J. Devries, John A. Woollam, Mathias Schubert, F. Frost

Department of Electrical and Computer Engineering: Faculty Publications

Amorphous tantalum oxide thin films were deposited by reactive rf magnetron sputtering onto [001] silicon substrates. Growth temperature, oxygen partial pressure, and total gas pressure have been varied to obtain thin films with different densities. The thin films were analyzed by glancing angle-of-incidence x-ray diffraction, atomic force microscopy, and variable angle-of-incidence spectroscopic ellipsometry in the near infrared to vacuum ultraviolet spectral region for photon energies from E=1 to 8.5 eV, and in the infrared region from E=0.03 to 1 eV. We present the dielectric function of amorphous tantalum oxide obtained by line shape analysis of the experimental ellipsometric …

Nonlinear Parameter Estimation Of Excitation Systems, Rajeev Bhaskar, Mariesa Crow, Eric Ludwig, Kelvin T. Erickson, Kirit S. Shah

Electrical and Computer Engineering Faculty Research & Creative Works

This paper details the nonlinear parameter estimation process of an IEEE AC1A type exciter using time-domain system identification techniques. This paper discusses nonlinear parameter estimation techniques, systematic and random noise mitigation strategies, and system validation. This study establishes a strong basis for excitation system parameter estimation.

Dc Power Bus Modeling Using A Circuit Extraction Approach Based On A Mixed-Potential Integral Equation Formulation And An Iterative Equation Solver, Jun Fan, James L. Drewniak, James L. Knighten

Electrical and Computer Engineering Faculty Research & Creative Works

A quick and simple approach is developed to perform circuit simulations for an equivalent circuit extracted from a first principles formulation for DC power bus structures. The simulations are done by solving the system equation using an iterative method. Good agreement between modeling and measurements demonstrate the effectiveness of the method, which is very suitable and computationally efficient for frequency-domain DC power modeling.

Design And Rule Base Reduction Of A Fuzzy Filter For The Estimation Of Motor Currents, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Fuzzy systems have been used extensively and successfully in control systems over the past few decades, but have been applied much less often to filtering problems. This is somewhat surprising in view of the dual relationship between control and estimation. This paper discusses and demonstrates the application of fuzzy filtering to motor winding current estimation in permanent magnet synchronous motors. Motor winding current estimation is an important problem because in order to implement effective closed-loop control, a good estimation of the current is needed. Motor winding currents are notoriously noisy because of electrical noise in the motor drive. We use …

Studies Related To The Design And Implementation Of A Magnetic Suspension And Balance System, Syed Adeel Akhtar Jafri

Electrical & Computer Engineering Theses & Dissertations

This thesis presents studies related to the magnetic suspension and balance system (MSBS) of the Princeton/ONR High Reynolds Number Testing Facility (HRTF). The main motivation for developing the MSBS is to provide interference free aero/hydrodynamic testing of submersible models, which will lead to more accurate measurements. From the controls point of view, the main specification of the MSBS is to robustly control the position of a submersible model in five degrees of freedom (DOF), including three translational as well as pitching and yawing positions. The MSBS should not only regulate the submersible model's position but should also allow for small …

Fabrication And Characterization Of Silicon Field Emitter Arrays, Aaron M. Brock

Electrical & Computer Engineering Theses & Dissertations

Field emission is a process through which the application of a large electric field to the surface of a material causes electron emission into vacuum. The electron emission current is a strong function of the geometry of the emitting material. The focus of this thesis is to investigate the effect of geometry on the emission current. Specifically, silicon field emitter arrays were fabricated using two separate fabrication processes termed the standard process and the new process. The uniformity of the arrays was measured experimentally. The arrays were used in field emission tests from which parameters controlling field emission were extracted. …

Performance Monitoring In Umr's Solar Car, Louis Mccarthy, Josh Pieper, Aaron Rues, Cheng-Hsiao Wu

Electrical and Computer Engineering Faculty Research & Creative Works

We describe the instrumentation in UMR's solar car. Accurate knowledge of the operating parameters inside the solar car is shown to be crucial to maintaining high efficiency and reliability. The power trackers keep the solar array operating at its highest efficiency by conditioning the input and maintaining the maximum power point of the solar cells.

Reduction Of Peak To Average Power Ratio In Ofdm And Ofdm-Cdma System, Jie Cheng

Theses

High Peak to Average Power Ratio is a main problem in Orthogonal Frequency Division Multiplexing(OFDM) system and Orthogonal Frequency Division Multiplexing -Code Division Multiple Access (OFDM-CDMA) system. Considering a compensated High Power Amplifier(HPA), in order to keep linearity for amplification, Input Back-Off(IBO) of the HP-A, has to be increased for handling a high PAPR. Higher 1130 will make HPA less efficient. Additionally, a signal with high PAPR will suffer clipping when PAPR is larger than 1130 of the HPA. Clipping can cause the distortion of the signal and deteriorate the performance of the system. Reduction of PAPR is a main …

Phase Tunability In A Conductor Backed Coplanar Waveguide Patch Antenna, Idan Mandelbaum

Theses

Traditionally beam steering in phase array antenna systems is achieved using tunable phase shifters or switched feed networks. Here, a tunable patch antenna element is suggested as a novel alternative to a combination of a radiating element and a phase shifter. A conductor backed coplanar waveguide patch antenna is chosen due to its suitability to mounted external tuning elements, using varactor diodes. Limited types of lumped tuning circuits, using varactor diodes, have been tested, though a lumped as well as distributed tuning is feasible in the chosen antenna configuration. Approximate analytical models for coplanar waveguide patch antennas with finite ground …

The Effect Of Cerium On The Anodic Behavior Of Pb-Ca-Sn Alloy In Sulfuric Acid Solution, Hou-Tian Liu, Jiong Yang, Hai-He Liang, Ji-Hua Zhuang, Wei-Fang Zhou

Journal of Electrochemistry

The cyclic voltammograms for Pb - 0.5 at% Ca - 1.5 at% Sn and Pb - 0.5 at% Ca - 1.5 at% Sn containing a certain amount of cerium in 4.5 mol·dm^-3 H₂SO₄ at 20℃ were measured between 0.6 V and 1.4 V(vs. Hg/Hg₂SO₄). The growth rate of the anodic Pb(Ⅱ) films formed on the mentioned alloy electrodes at 0.9 V in the same sulfuric acid medium was investigated using the Linear Sweep Voltammetry. The variation with electrode potential of the real part of the impedence (Z’) for the anodic Pb(Ⅱ) films …

The Electro-Catalytic Oxidation Of Hcooh On Electrodeposited Pd Electrode, Quan Zhou, Cun-Zhong Zhang, Xiao-Lin Lu, Zhong-Da Wu

Journal of Electrochemistry

The coherent electroplates were prepared by electro depositing Pd on supporting materials glassy carbon. The surface morphology of the electrodes was examined by SEM. The electro oxidation of HCOOH in HClO₄ solution was investigated by using cyclic voltammetry. The results show that the deposited conditions in the preparation of electrodes by electro depositing Pd affect the electrodes electro catalytic activity to the oxidation of HCOOH. The platinized Pd electrode on GC substrates using large current density is of higher catalytic activity to the oxidation of HCOOH than Pd electrode. The electro catalytic activity of PdO formed on the Pd …

A Study On Stochastic Resonance For The Process Of Active-Passive Transition Of Iron In Sulfuric Acid, Hong-Bo Ding, Bao-Yun Xia, Chun-Sheng Yin, Zhong-Xiao Pan, Renato Seeber

Journal of Electrochemistry

The bistable characteristics of the process of active passive transition of iron in sulfuric acid was described and the stochastic resonance phenomenon in the process was simulated.

Cathodic Indirect Oxidation Of Organic Compounds(Ⅱ)——Cathodic Indirect Epoxidation Of Olefine, Xue-Ying Zhang, Bao-Qiu Cui, Deng-Ping Gu, Wei Li

Journal of Electrochemistry

We described a novel cathodic indirect epoxidation system in which O₂ was first cathodically reduced to H₂O₂. Then VO(acac)₂ was oxidized by H₂O₂ homogeneously to VO(acac)₂OOH which was used to epoxidize some olefine such as maleic, fumaric and crotonic acids. Many affecting factors on the current efficiency were optimized. The research will contribute to the developments of organic electrosynthesis.

The Study On Lithiated Titanium Composite Oxides As Negative Electrode For Lithium-Ion Battery, Xiao-Yan Yang, Shou-Nan Hua, Shu-Yong Zhang

Journal of Electrochemistry

Lithiated titanium composite oxides Li₄Ti₅O₁₂ were prepared from Li₂CO₃ and TiO₂. The XRD results of this composite oxides indicated that the compound had a spinel structure. The electrochemical behavior of lithiated titanium composite oxides was examined. The results showed that this material had an excellent cyclic capability and reversibility for lithium insertion, and had high specific capacity: the initial discharge capacity was 300 mAh·g^-1 , and the reversible capacity was 100 mAh·g^-1 . The discharge plateau (about 1.5 V) and the charge plateau (about 1.6 V) were very …

Studies Of The LialYNi1-YO2 As Cathode Materials For Rechargeable Lithium Ion Batteries, Xiao-Gan Li, Wei-Hua Qiu, Chuan-Gang Lin, Qing-Guo Liu

Journal of Electrochemistry

In this paper, we have synthesized series of single-phase LiAl_yNi_1-yO₂ (differentive in value-y) by solid reaction. Through examining their electrothemical properties, found that, under a proper sintering condition, Li_xAl_0.25Ni_0.75O₂ solution for cathode materials of rechargeable lithium ion batteries showed more pleasing properties in overcharge-resist and cycling life (vs LiNiO₂). When x>1, the capacity can be kept 125mAh/g after 30 cycles under higher charged/discharged voltages ranging from 3.0 V to 4.8 V, whereas that of pure LiNiO₂ has only 61 nAh/g after 25 cycles. The …

Synthesis Of Li1+XMn2O4 Cathode Material For Lithium-Ion Batteries With Solution Method, Pei-Song Liu, Sing-Quarn Liu, Qing Li, Zhao-Yong Chen, Bai-Lan Zhang, Zuo-Long Yu

Journal of Electrochemistry

The cathode materials Li_1+xMn₂O₄ were prepared with citric acid complexing and solution impregnating methods. Structure characterization and specific surface area test were performed by means of XRD, BET methods, the influences of calcination temperature, Li/Mn molar ratio and raw materials on the structure and electrochemical capacity of samples have beem examined. The results showed that the Li/Mn molar ratio and calcimation temperature were the key factors affecting the electrochemical capacity of cathode materias. The optimum conditions for synthesis of  Li_1+xMn₂O₄ cathode material were 0≤x≤0.05 and calcined at 750°C. The initial …

The Effect Of Anode Thickness In Sofcs With Anode Supported Ysz Film, Yi-Huang Zhang, Yi Jiang, Zi-Gui Lu, Yong-Lai Dong, Jing-Wang Yan

Journal of Electrochemistry

Solid oxide fuel cells with supported yttria stabilized zirconia electrolyte films on anode substrates of various thickness have been fabricated. The electrochemical performances of the SOFCs have been examined. The results showed that the cell performance was limited by the anodic overpotential, which is caused mainly by a concentration polarization when the anode substrate is thick. The anodic overpotential was reduced obviously as the thickness of anode substrate was decreased. As a result, the performance of the SOFC cell was improved. With a 0.5 mm anode substrate, a SOFC cell produced a power density about 0.19 W/cm² at 800 …