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Investigations Of Transverse Arc Array Laser Action In Nitrogen Gas, Kee Siang Goh Jan 2000

Investigations Of Transverse Arc Array Laser Action In Nitrogen Gas, Kee Siang Goh

Student Works (2000-2009)

In almost all pulsed gas lasers, transverse electrical discharge is employed in the excitation of the atoms or molecules. These lasers normally employ discharge across a pair of common electrodes to provide large volume and uniform glow discharge. The scaling of output power in such lasers is obtained by increasing the volume of the discharge and also the pressure of the discharge gas. For this reason. the energy coupled into the discharge channel is kept low enough to avoid arcing. Under these circumstances, the electron temperature of such uniform glow discharge is not sufficient to produce excitation of VUV or …

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Optimisation Of Transverse Arc Array Laser, Albert Kok Foo Ng Jan 2000

Optimisation Of Transverse Arc Array Laser, Albert Kok Foo Ng

Student Works (2000-2009)

A novel discharge scheme is proposed for the pumping of short wavelen,gth lasers. This scheme had been tested to produce fast current pulse and a 5 kA current in 60 nsec is obtained. Lasing action has been observed by using nitrogen gas. The laser line is 337 nm from the strong transitions of nitrogen molecules. The new discharge scheme is based on the concept of an arc array amplifier. It essentially consists of 48 pairs of electrodes which are lined up to form an array of arc discharge. Its electrical circuitry allows each pair of the electrodes to be decoupled …

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Scene-Based Nonuniformity Correction With Video Sequences And Registration, Russell C. Hardie, Majeed M. Hayat, Earnest Armstrong, Brian Yasuda Jan 2000

Scene-Based Nonuniformity Correction With Video Sequences And Registration, Russell C. Hardie, Majeed M. Hayat, Earnest Armstrong, Brian Yasuda

Electrical and Computer Engineering Faculty Research and Publications

We describe a new, to our knowledge, scene-based nonuniformity correction algorithm for array detectors. The algorithm relies on the ability to register a sequence of observed frames in the presence of the fixed-pattern noise caused by pixel-to-pixel nonuniformity. In low-to-moderate levels of nonuniformity, sufficiently accurate registration may be possible with standard scene-based registration techniques. If the registration is accurate, and motion exists between the frames, then groups of independent detectors can be identified that observe the same irradiance (or true scene value). These detector outputs are averaged to generate estimates of the true scene values. With these scene estimates, and …

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Stochastic Stability Of The Continuous-Time Extended Kalman Filter, K. Reif, S. Gunther, Edwin E. Yaz, R. Unbehauen Jan 2000

Stochastic Stability Of The Continuous-Time Extended Kalman Filter, K. Reif, S. Gunther, Edwin E. Yaz, R. Unbehauen

Electrical and Computer Engineering Faculty Research and Publications

he error behaviour of the extended Kalman filter is analysed. It is proved that the estimation error remains bounded if the system satisfies a detectability condition and both the initial estimation error and the disturbing noise terms are small enough. Moreover, some selected cases with both bounded and unbounded estimation error are demonstrated by numerical simulations.

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Pid Compensation Of Time Delayed Processes: A Survey, Aidan O'Dwyer Jan 2000

Pid Compensation Of Time Delayed Processes: A Survey, Aidan O'Dwyer

Conference papers

An extensive literature exists on the PID compensation of time delayed processes. It is possible to identify themes that are common to many of the available techniques. The intention of the paper is to provide a framework against which the literature may be viewed.

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Vhdl Design And Simulation For Embedded Zerotree Wavelet Quantisation, Hung Huynh Jan 2000

Vhdl Design And Simulation For Embedded Zerotree Wavelet Quantisation, Hung Huynh

Theses : Honours

This thesis discusses a highly effective still image compression algorithm – The Embedded Zerotree Wavelets coding technique, as it is called. This technique is simple but achieves a remarkable result. The image is wavelet-transformed, symbolically coded and successive quantised, therefore the compression and transmission/storage saving can be achieved by utilising the structure of zerotree. The algorithm was first proposed by Jerome M. Shapiro in 1993, however to minimise the memory usage and speeding up the EZW processor, a Depth First Search method is used to transverse across the image rather than Breadth First Search method as initially discussed in Shapiro's …

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Comparison Of A Heuristic Dynamic Programming And A Dual Heuristic Programming Based Adaptive Critics Neurocontroller For A Turbogenerator, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley Jan 2000

Comparison Of A Heuristic Dynamic Programming And A Dual Heuristic Programming Based Adaptive Critics Neurocontroller For A Turbogenerator, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a neurocontroller for a turbogenerator that augments/replaces the conventional automatic voltage regulator and the turbine governor. The neurocontroller uses a novel technique based on the adaptive critic designs with emphasis on heuristic dynamic programming (HDP) and dual heuristic programming (DHP). Results are presented to show that the DHP based neurocontroller is robust and performs better than the HDP based neurocontroller, as well as the conventional controller, especially when the system conditions and configuration changes.

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An Analog Front-End Speech Processor Using The Ratio Spectrum, John G. Harris, Shao Jen Lim Jan 2000

An Analog Front-End Speech Processor Using The Ratio Spectrum, John G. Harris, Shao Jen Lim

Electrical and Computer Engineering Faculty Research & Creative Works

We have combined the standard front-end filter bank with a feature extraction process to produce a model that requires dramatically less hardware (or software). This new model, based on the frequency-sampled ratio spectrum, can be interpreted as a small set of constant-Q filters whose center frequencies adapt to locations of high signal energy. The resulting feature vectors are shown to outperform several competing techniques for phoneme recognition. Results from fabricated CMOS analog VLSI circuits illustrate a hardware efficient method to sample the ratio spectrum.

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Monaural Cue Sound Localizer, John G. Harris, Chiang Jung Pu, Jose C. Principe Jan 2000

Monaural Cue Sound Localizer, John G. Harris, Chiang Jung Pu, Jose C. Principe

Electrical and Computer Engineering Faculty Research & Creative Works

We describe the first single microphone sound localization system and its inspiration from theories of human monaural sound localization. Reflections and diffractions caused by the external ear (pinna) allow humans to estimate sound source elevations using only one ear. Our single microphone localization model relies on a specially shaped reflecting structure that serves the role of the pinna. Specially designed analog VLSI circuitry uses echo-time processing to localize the sound. A CMOS integrated circuit has been designed, fabricated, and successfully demonstrated on actual sounds.

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Two Separate Continually Online Trained Neurocontrollers For Excitation And Turbine Control Of A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2000

Two Separate Continually Online Trained Neurocontrollers For Excitation And Turbine Control Of A Turbogenerator, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of two separate continually online trained (GOT) artificial neural network (ANN) controllers for excitation and turbine control of a turbogenerator connected to the infinite bus through a transmission line. These neurocontrollers augment/replace the conventional automatic voltage regulator and the turbine governor of a generator. A third COT ANN is used to identify the complex nonlinear dynamics of the power system. Results are presented to show that the two COT ANN controllers can control turbogenerators under steady state as well as transient conditions and thus allow turbogenerators to operate more closely to their steady state stability …

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A Hysteresis Current-Regulated Control For Multi-Level Drives, Keith Corzine Jan 2000

A Hysteresis Current-Regulated Control For Multi-Level Drives, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

Most multi-level converters are controlled through the use of voltage-source based control techniques such as space-vector modulation or multi-level sine-triangle modulation. However, in many applications such as field oriented drives, a high bandwidth current-source inverter based control is more desirable. In this paper, the concept of a multi-level hysteresis current-source control is set forth. The new control is experimentally verified using a four-level converter/induction motor drive system and the results are compared to a space vector modulation controller. A dynamic study involving a step change in current command demonstrates the controls high bandwidth.

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Adaptive Critic Based Neurocontroller For Turbogenerators With Global Dual Heuristic Programming, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley Jan 2000

Adaptive Critic Based Neurocontroller For Turbogenerators With Global Dual Heuristic Programming, Ganesh K. Venayagamoorthy, Donald C. Wunsch, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Turbogenerators are nonlinear time varying systems. This paper presents the design of a neurocontroller for such a turbogenerator that augments/replaces the traditional automatic voltage regulator (AVR) and the turbine governor using a novel technique based on the adaptive critic designs (ACDs) with emphasis on global dual heuristic programming (GDHP). Simulation results are presented to show that the neurocontroller derived with the GDHP approach is robust and its performance is better when compared with that derived with other neural network technique, especially when system conditions and configuration changes.

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Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna Dec 1999

Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna

Tanzania Journal of Engineering and Technology (TJET)

Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …

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Results Using An Alternative Approach To Channel Equalization Using A Pattern Classification Strategy, Frank M. Caimi, Gamal A. Hassan Dec 1999

Results Using An Alternative Approach To Channel Equalization Using A Pattern Classification Strategy, Frank M. Caimi, Gamal A. Hassan

Electrical Engineering and Computer Science Faculty Publications

In underwater acoustic communication, (ACOMMs), ocean surface and bottom conditions create multi path propagation's for the transmitted signal that result in Inter symbol Interference (ISI) at the receiver. Generally, Equalization, Diversity IBeam forming, and Channel Coding are three independent techniques that are used to improve received signal quality. Equalization compensates for ISI created by a band-limited, time-dispersive channel through implementation of specialized filtering schemes within the receiver. The coefficients of the equalizer need to be continuously adjusted to compensate for the variability in the channel. Since the number of states required by the equalizer (or beam former) is finite, and …

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Near-Band-Gap Cupt-Order-Induced Birefringence In Al0.48Ga0.52Inp2, Mathias Schubert, Tino Hofmann, Bernd Rheinlander, Ines Pietzonka, Torsten Sass, Volker Gottschalch, John A. Woollam Dec 1999

Near-Band-Gap Cupt-Order-Induced Birefringence In Al0.48Ga0.52Inp2, Mathias Schubert, Tino Hofmann, Bernd Rheinlander, Ines Pietzonka, Torsten Sass, Volker Gottschalch, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

The order-induced birefringence in the near-band-gap spectral range (0.75 to 2.5 eV), and its dependence on the degree of ordering η is reported for Al0.48Ga0.52InP2. Transmission and reflection generalized variable angle spectroscopic ellipsometry, dark-field spectroscopy, and cross-polarized reflectance difference spectroscopy (CRDS) are used to determine precisely the room-temperature dielectric functions for polarization parallel and perpendicular to the ordering direction of a series of spontaneously CuPt-ordered samples grown by metalorganic vapor-phase epitaxy. The CRDS technique is introduced as an approach to sense extremely weak anisotropy at oblique angles of incidence. The observed order birefringence is …

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Approximation And Optimization Of An Auditory Model For Realization In Vlsi Hardware, Samuel L. Sangregory Dec 1999

Approximation And Optimization Of An Auditory Model For Realization In Vlsi Hardware, Samuel L. Sangregory

Theses and Dissertations

The Auditory Image Model (AIM) is a software tool set developed to functionally model the role of the ear in the human hearing process. AIM includes detailed filter equations for the major functional portions of the ear. Currently, AIM is run on a workstation and requires 10 to 100 times real-time to process audio information and produce an auditory image. An all-digital approximation of the AIM which is suitable for implementation in very large scale integrated circuits is presented. This document details the mathematical models of AIM and the approximations and optimizations used to simplify the filtering and signal processing …

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Multimode Solution For The Reflection Properties Of An Open-Ended Rectangular Waveguide Radiating Into A Dielectric Half-Space: The Forward And Inverse Problems, R. Zoughi, Aaron D. Benally, Karl Joseph Bois Dec 1999

Multimode Solution For The Reflection Properties Of An Open-Ended Rectangular Waveguide Radiating Into A Dielectric Half-Space: The Forward And Inverse Problems, R. Zoughi, Aaron D. Benally, Karl Joseph Bois

Electrical and Computer Engineering Faculty Research & Creative Works

Open-ended rectangular waveguides are extensively used in nondestructive dielectric material evaluation. The dielectric properties of an infinite-half space of a material are calculated from the measured reflection properties referenced to the waveguide aperture. This calculation relies on a theoretical and numerical derivation of the reflection coefficient likewise referenced to the waveguide aperture. Most of these derivations assume the dominant mode field distribution across the waveguide aperture. However, when dealing with low permittivity and low loss dielectric materials, there may exist significant errors when calculating the dielectric properties from the measured reflection coefficient. These errors have also shown to be more …

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An Accurate Method Of Neglecting Dynamic Saliency Of Synchronous Machines In Power Electronic Based Systems, Steven Pekarek, E. A. Walters Dec 1999

An Accurate Method Of Neglecting Dynamic Saliency Of Synchronous Machines In Power Electronic Based Systems, Steven Pekarek, E. A. Walters

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, motivations for neglecting dynamic saliency in the detailed models of power electronic based systems are presented, A new method of neglecting dynamic saliency is then introduced in which approximate operational impedances are derived from original dynamic salient models. New machine parameters are obtained by fitting to the approximate impedance curves, yielding model parameters in which dynamic saliency is eliminated. An example synchronous machine/converter system is provided that demonstrates the accuracy and increased simulation efficiency resulting from this technique. Therein, errors resulting from neglecting dynamic saliency are reduced from greater than 25% using traditional approximations to less than …

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Dielectric Plug-Loaded Two-Port Transmission Line Measurement Technique For Dielectric Property Characterization Of Granular And Liquid Materials, K. Mubarak, R. Zoughi, Aaron D. Benally, Karl Joseph Bois, Larry F. Handjojo Dec 1999

Dielectric Plug-Loaded Two-Port Transmission Line Measurement Technique For Dielectric Property Characterization Of Granular And Liquid Materials, K. Mubarak, R. Zoughi, Aaron D. Benally, Karl Joseph Bois, Larry F. Handjojo

Electrical and Computer Engineering Faculty Research & Creative Works

There are numerous dielectric property characterization techniques available in the microwave regime each with its own uniqueness, advantages and disadvantages. The two-port completely-filled waveguide (transmission line) technique is a robust measurement approach which is well suited for solid dielectric materials. In this case, the dielectric material can be relatively easily machined to fit inside the waveguide and the subsequent measurement of the scattering parameters of this two-port device renders the dielectric properties of the material filling the waveguide. However, this technique is not well suited for measuring the dielectric properties of granular and liquid materials. These materials are used in …

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The Electrochemical Behaviors Of Superoxide Dismutase At Promoter Modified Gold Electrode, Xia-Qin Wu, Xiao-Yun Meng, Zhe-Su Wang, Zong-Rang Zhang Nov 1999

The Electrochemical Behaviors Of Superoxide Dismutase At Promoter Modified Gold Electrode, Xia-Qin Wu, Xiao-Yun Meng, Zhe-Su Wang, Zong-Rang Zhang

Journal of Electrochemistry

The electron-transfer process of superoxide dismutase was investigated by cyclic voltammetry at the 4,4'-dithiodipyridine, L-cysteine, histidine and arginine modified gold wire electrodes repectively. The quasi-reversible behavior was observed at L-cysteine modified gold electrode. An irreversible electrochemical behavior has been observed at hisdinine modified gold wire electrode.

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Study On Electrochemical Reduction Properties Of Nitrobenzene, Chu-Na Ma, Wen-Kui Zhang, Hui Huang, Yong-Ping Gan Nov 1999

Study On Electrochemical Reduction Properties Of Nitrobenzene, Chu-Na Ma, Wen-Kui Zhang, Hui Huang, Yong-Ping Gan

Journal of Electrochemistry

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

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High Performance Proton Exchange Membrane Fuel Cells, Jing-Rong Yu, Bao-Lian Yi, Ming Han, Xiao-Liang Cheng, Zhi-Gang Shao, Jing-Xin Zhang Nov 1999

High Performance Proton Exchange Membrane Fuel Cells, Jing-Rong Yu, Bao-Lian Yi, Ming Han, Xiao-Liang Cheng, Zhi-Gang Shao, Jing-Xin Zhang

Journal of Electrochemistry

Proton-exchange membrane fuel cells(PEMFC) using a perfluorosulfonic acid proton exchange membrane as an electrolyte can simplify water and electrolyte management. In this paper, the effects of thickness of PEM on the performance of PEMFC were studied. The Nafion-112 PEM and low platinum loading E-TEK electrode yielded very high power density, of the order of 0.95 W/cm2. The energy-conversion efficiency, the degree of platinum utilization and stability for PEMFC using Nafion 112 and E-TEK electrode were also investigated.

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Photoelectrochemical Studies On The Tio2 Nanostructured Porous Film Sensitized By Cyanine Dye, Li Zhang, Mai-Zhi Yang, Xue-Bin Qiao, Yan-Zhong Hao, En-Qing Gao, Sheng-Min Cai Nov 1999

Photoelectrochemical Studies On The Tio2 Nanostructured Porous Film Sensitized By Cyanine Dye, Li Zhang, Mai-Zhi Yang, Xue-Bin Qiao, Yan-Zhong Hao, En-Qing Gao, Sheng-Min Cai

Journal of Electrochemistry

The photoelectrochemical behaviors of the TiO2 nanostructured porous film sensitized by cyanine dye were investigated in this paper. The results showed that the excitaed state level matched the conduction band edge of TiO2 nanoparticle. Therefore the sensitization of the dye can increase the photocurrent intensity of the TiO2 nanostructured electrode obviously and results in a red-shift of optical absorption from the ultra-violet region to the visible. As a result, the light-to-electricity conversion efficiency was improved evidently, the maximum value of IPCE has reached 12.1%.

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Electro-Oxidation Of Phenol On Sno2/Ti Electrodes Prepared By Thermal Oxidation, Qing-Song Zhang, Hui-Huang Wu Nov 1999

Electro-Oxidation Of Phenol On Sno2/Ti Electrodes Prepared By Thermal Oxidation, Qing-Song Zhang, Hui-Huang Wu

Journal of Electrochemistry

A SnO2/Ti electrode prepared by thermal oxidation was used as the anode for galvanostatic electrolysis in acidic solution containing phenol, the time-dependances of phenol concentration, chemical oxygen demand in solution(COD) and instantaneous current efficiency were determined during electrolysis. The results show that with the SnO2/Ti anode instead of Pt, the COD significantly decreases at the same charge passage, and average current efficiency of oxidation increases by three times. The mechanism for phenol oxidation at two electrodes was discussed.

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Investigation Of Sodium Hypophosphite Anodic Oxidizing Behavior In The Process Of Acid Electroless Nickel Deposition, Mei-Yuan Wang, Ya-Fei Kuang, Yan Xu Nov 1999

Investigation Of Sodium Hypophosphite Anodic Oxidizing Behavior In The Process Of Acid Electroless Nickel Deposition, Mei-Yuan Wang, Ya-Fei Kuang, Yan Xu

Journal of Electrochemistry

The anodic oxidizing behavior of sodium hypophosphite in the process of electroless nickle deposition (pH=5.5) was investigated with the linear potential sweep method and alternating current impedance. The results indicated that, the oxidation of NaH2PO2 was a complicated electrochemical process and affected by the concentration of NaH2PO2, the temperature of the bath, the sweep rate and the existence of nickel ion. The NaH2PO2 electrooxidation reaction was very likely preceded by heterogeneous interface transformation process, which might be the control step of the whole anodic process.

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Studies Of The Electrode Preparation Of Electrode From Lead Carbonate For Lead Acid Batteryⅰ. The Activation Of The Pme, Zhong-Xu Dai, Di-Hua Wang, Jun-Wei Jiang, Yun-Hong Zhou, Jin-Yun Zou Nov 1999

Studies Of The Electrode Preparation Of Electrode From Lead Carbonate For Lead Acid Batteryⅰ. The Activation Of The Pme, Zhong-Xu Dai, Di-Hua Wang, Jun-Wei Jiang, Yun-Hong Zhou, Jin-Yun Zou

Journal of Electrochemistry

Lead carbonate which was an intermediate product in lead hydrometallurgy without pollution of lead vapor and sulfur dioxide was selected as electrode material of lead-acid batteries. In the present work, the performances of PbO2/PbSO4 or PbSO4/Pb electrode transformed from PbCO3 have been investigated by powder microelectrode technique combined with cyclic voltammetry. The results show that the CV characteristics of either negative or positive electrode prepared from PbCO3 is as good as that of both electrodes made from lead oxide produced by mill machine,when a powder microelectrode with PbCO3 transformed into PbSO 4 …

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

Studies On Methods Of Fuel Cells Electrodes Preparation, Jun Gu, Sheng Sui, Guang-Qiang Li, Zhitong Sui

Journal of Electrochemistry

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

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Accuracy Of Scatterometer-Derived Winds Using The Cramer-Rao Bound, David G. Long, Travis E. Oliphant Nov 1999

Accuracy Of Scatterometer-Derived Winds Using The Cramer-Rao Bound, David G. Long, Travis E. Oliphant

Faculty Publications

A wind scatterometer makes measurements of the normalized radar-backscatter coefficient O of the ocean surface. To retrieve the wind, a geophysical model function (GMF), which relates O to the near-surface wind, is used. The wind vector can be estimated using maximum-likelihood techniques from several O measurements made at different azimuth angles. The probability density of the measured O is assumed to be Gaussian with a variance that depends on the true O and therefore, depends on the wind through the GMF. With this model for wind estimation, the Cramer-Rao (C-R) bound is derived for wind estimation, and its implications for …

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Crossover Photonic Switching Network With Cmos/Seed Smart Pixel Device And 2d Optical Fiber Bundle Array, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Deming Liu Nov 1999

Crossover Photonic Switching Network With Cmos/Seed Smart Pixel Device And 2d Optical Fiber Bundle Array, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Deming Liu

Electro-Optics and Photonics Faculty Publications

A 16 X 16 Crossover photonic switching network with hybrid integrated CMOS/SEED smart pixel device and 2D optical fiber bundle array I/O access device is reported in this paper. SEEd array devices ar used as light receivers and transmitters, while CMOS devices make efficient logical processing. 4 X 40 2D multilayer optical fiber bundle arrays are fabricated and are used as I/O access devices in the crossover photonic switching network. The center to center spacing between adjacent optical fibers in the same layer of the fiber array is 125micrometers , and the spacing between adjacent layers is 250micrometers . Displacing …

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Evaluation Of The Transport Properties Of Gasb For Bipolar Applications Through Monte Carlo Simulations, Damayanthi Palaniappan Oct 1999

Evaluation Of The Transport Properties Of Gasb For Bipolar Applications Through Monte Carlo Simulations, Damayanthi Palaniappan

Electrical & Computer Engineering Theses & Dissertations

GaAs is currently the semiconductor material of choice for high speed, low power applications. Its electronic transport properties are superior to almost all other semiconductors. It is also used in a variety of bipolar applications such as photodetectors and photo-mixers. However, as is well known, the hole mobility and related transport parameters of GaAs are not very good. This is a serious drawback, and poses a potential problem for all applications involving bipolar conductivity. In order to increase the high :frequency limits and high-speed capability of bipolar devices, the choice of an alternative material, therefore, becomes necessary. An important first …

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