Engineering Commons^™

Graded Refractive Index Silicon Oxynitride Thin Film Characterized By Spectroscopic Ellipsometry, Paul G. Snyder, Yi-Ming Xiong, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

A graded refractive index silicon oxynitride (SiO_xN_y) thin film was prepared on a silicon substrate by ion assisted deposition. Spectroscopic ellipsometry (SE) was used to optically analyze the film. The measured SE spectra (2500-8200 Å) were analyzed with several fitting models, whose construction was based on an Auger depth profile of the film. In each model, the optical response of SiO_xN_y was described using the Bruggeman effective medium approximation, by modeling it as a physical mixture of two distinct phases: silicon dioxide and silicon nitride. Grading was modeled by varying the silicon nitride …

Silicon Nitride/Silicon Oxynitrid/Silicon Dioxide Thin Film Multilayer Characterized By Variable Angle Spectroscopic Ellipsometry, Yi-Ming Xiong, Paul G. Snyder, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Variable angle spectroscopic ellipsometry (VASE) was used to nondestructively characterize a silicon nitride (Si₃N₄)/silicon oxynitride (SiO_xN_y)/silicon dioxide (SiO₂) thin film multilayer structure, in which Si₃N₃ and SiO_xN_y layers were deposited by plasma enhanced chemical vapor deposition and low-pressure chemical vapor deposition, respectively. The measured VASE spectra (3500-8200 Å) were analyzed with an appropriate multilayer fitting model, in which the SiO_xN_y layer was modeled. in the Bruggeman effective medium approximation (EMA), to be a physical mixture of two distinct phases, SiO_{2 …}

Feature-Based Correlation Filters For Distortion Invariance, Samuel Peter Kozaitis, Robert Petrilak, Wesley E. Foor

Electrical Engineering and Computer Science Faculty Publications

In an optical correlator, binary phase-only filters (BPOFs) that recognize objects that vary in a nonrepeatable way are essential for recognizing objects from actual sensors. An approach is required that is as descriptive as a BPOF yet robust to object and background variations of an unknown or nonrepeatable type. We developed a BPOF that was more robust than a synthetic discriminant function (SDF) filter. This was done by creating a filter that retained the invariant features of a training set. By simulation, our feature-based filter offered a range of performance by setting a parameter to different values. As the value …

Optical Estimation Of Fractal Dimension For Image Assessment, Samuel Peter Kozaitis, Rufus H. Cofer

Electrical Engineering and Computer Science Faculty Publications

We modeled an optical system for estimation of the fractal dimension to provide a measure of surface roughness for an entire image and for image segmentation. Although the simulated optical result was similar to that calculated by digital techniques, both suffered from problems known to occur with estimating fractal dimension. Furthermore, the optical estimation did not have as good a resolution as that obtained with digital estimates due primarily to the limited dynamic range of the detector.

Multiresolution Template Matching Using An Optical Correlator, Samuel Peter Kozaitis, Zia Saquib, Rufus H. Cofer, Wesley E. Foor

Electrical Engineering and Computer Science Faculty Publications

Infrared imagery of 512 × 512 pixels was processed with 128 × 128 arrays by computer simulation of an optical correlator using various correlation filters. Pyramidal processing using binary phase-only filters (BPOFs), synthetic discriminant function (SDF) filters, and feature-based filters was used to process an entire image in parallel at different resolutions. Results showed that both SDF and feature-based filters were more robust to the effects of thresholding input imagery than BPOFs. The feature-based filters offered a range of performance by setting a parameter to different values. As the value of the parameter was changed, correlation peaks within the training …

Rotating-Wave Approximation In High-Gain Lasers, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Semiclassical models for lasers typically incorporate a fundamental simplification called the rotating-wave approximation. In this study the rotating-wave approximation is reexamined, and its implications for the simplest problem of a steady-state laser oscillator are considered in detail. It is found that for practical laser operating conditions the errors resulting from this approximation may not always be negligible.

The Degradation Of Aluminium Cathodes By Fluoride Ion During Zinc Electrowinning, J. S. Han, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The influence of fluoride ions on aluminum cathode surface degradation during zinc electrowinning has been studied. Electrolyte with a composition similar to that employed in plant operations has been used. A direct correlation is shown between the electrolyte fluoride content and the number of deposition cycles possible before zinc removal becomes difficult. The role of initial nucleation and starting electrode morphology is discussed in terms of the degree of adherence observed. Electrochemical tests have also been made on the electrodes at various stages of the process in an attempt to gain a better fundamental understanding of the mechanisms responsible for …

Neural Modeling And Control Of A Distillation Column, James Edward Steck, K. Krishnamurthy, Bruce M. Mcmillin, Gary G. Leininger

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Control of a nine-stage three-component distillation column is considered. The control objective is achieved using a neural estimator and a neural controller. The neural estimator is trained to represent the chemical process accurately, and the neural controller is trained to give an input to the chemical process which will yield the desired output. Training of both the neural networks is accomplished using a recursive least squares training algorithm implemented on an Intel iPSC/2 multicomputer (hypercube). Simulated results are presented for a numerical example.

New Speckle Technique For Noncontact Measurement Of Small Creep Rates, Donald D. Duncan, F. Fausten Mark, Lawrence W. Hunter

Electrical and Computer Engineering Faculty Publications and Presentations

A highly sensitive method for measuring thermal expansion, mechanical strain, and creep rates has been developed. This technique is based on Yamaguchi's speckle strain gauge concept, but uses a novel data-processing approach that provides estimates of the time rate of inplane strain. The approach is appropriate for assessing very small strain rates in hostile environments. It provides simultaneous global estimates of the strain at both small and large gauge sizes. This may be of importance in studying materials with different short- and long-range orders. General advantages of the technique are compact design, modest resolution requirements, insensitivity to surface microstructure changes …

Evidence That Free Fatty Acid-Iron Complexes Directly Initiate Lipid Peroxidation In Vitro And In Vivo: A New Mechanism Of Oxidative Stress, Steven C. Salaris, Charles F. Babbs, Joann Pham, John J. Turek

Weldon School of Biomedical Engineering Faculty Working Papers

Through a series of biochemical and histochemical experiments we explored the novel hypothesis that iron and free fatty acids, liberated after tissue injury, combine to form liposoluble complexes that directly initiate lipid peroxidation. The addition of 100 M ferric iron to 30 mM linoleate suspensions at pH 7.4 produced time dependent lipid peroxidation, measured as conjugated diene formation. Complexes of 100 M ferric iron and 600 M pentanoate also initiated formation of conjugated dienes in linoleate suspensions and formation of malondialdehyde-like materials in rat liver slices. A histochemical stain for free fatty acids revealed positive reactions within cell membranes in …

Ground Water Contamination: What You Need To Know, David B. Mcwhorter

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

14 pages.

Contains references.

Quality Meets Quantity: San Gabriel Valley, California, Mark J. Klaiman

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

23 pages (includes maps).

Quality Meets Quantity: San Gabriel Valley, California: The Metropolitan Water District Of Southern California Proposal, Thomas M. Stetson

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

19 pages (includes illustrations and maps).

Contains footnotes.

Transport Modeling – Technical And Legal Issues, Adrian Brown

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

27 pages.

Contains footnotes.

Groundwater Cleanup: Is It Worth It?, Carolyn B. Doty

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

5 pages.

Contains references.

The Rocky Mountain Arsenal: Groundwater Contamination And Clean-Up Activities, Connally E. Mears, Elaine H. Heise

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

26 pages (includes illustrations and map).

The Evolution And Performance Of Groundwater Management Institutions In Southern California, William Blomquist

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

12 pages.

Pre-Trial Case Preparation In Complex Groundwater Litigation: The Lawyer’S Role, Michael D. Shimmin

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

12 pages.

Arizona Groundwater Management Act: Recent Issues And Future Prospects, Katharine Jacobs, Robert Glennon

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

26 pages.

Data, Correspondence, Reports, And Exhibits For Ground Water Rights Cases (Or, Challenges In Developing And Presenting Data To Support A Ground Water Rights Case), Robert E. Brogden

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

17 pages.

Agenda: Uncovering The Hidden Resource: Groundwater Law, Hydrology And Policy In The 1990s, University Of Colorado Boulder. Natural Resources Law Center, Rocky Mountain Ground-Water Conference (1992), Colorado Ground-Water Association

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

Sponsored by Natural Resources Law Center, University of Colorado School of Law and the Rocky Mountain Ground-Water Conference, organized by the Colorado Ground-Water Association.

Faculty for the conference included University of Colorado School of Law professor Lawrence J. MacDonnell.

Nearly half the people in the United States rely on groundwater as their primary water source. As demands for groundwater grow, it becomes increasingly important for lawyer and technical professionals to understand the legal and hydrologic issues arising in groundwater development, use, and protection. These issues will be the focus of the Center's thirteenth annual summer program, June 15-17, 1992.

This …

Well Interference And Ground Water Mining: The Legal Framework, J. David Aiken

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

16 pages.

Aquifer/Stream Relationships And Aquifer Recharge, Robert A. Longenbaugh

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

13 pages.

Contains references.

Exporting Ground Water From Colorado’S San Luis Valley: Awdi’S Nontributary Claim, Eric J. Harmon

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

12 pages.

Contains 1 page of references.

Selected Legal Issues Relating To Application Of American Water Development, Inc., Case No. 86 Cw 46, Water Division No. 3, Colorado, Charles B. White

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

13 pages.

Meeting Urban Water Demands In Nevada, The Las Vegas Proposal, Terry Katzer, Kay Brothers

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

10 pages (includes map).

Contains references.

Meeting Urban Water Demands In Nevada: The Las Vegas Proposal [Outline], R. Michael Turnipseed

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

4 pages.

Ground-Water Modeling Issues In Ground-Water Development: Types Of Models/Choosing The Right Model, Paul K.M. Van Der Heijde

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

26 pages.

Contains 3 pages of references.

Ground-Water Modeling Issues In Ground-Water Development: Model Calibration And Verification, Paul K.M. Van Der Heijde

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

36 pages (includes illustrations and maps).

Contains references.

Conceptualization Of Hydrologic Systems [Outline], Kenneth E. Kolm

Uncovering the Hidden Resource: Groundwater Law, Hydrology, and Policy in the 1990s (Summer Conference, June 15-17)

4 pages.