Summer
Research Experience for Undergraduates (REU)
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- 2005 Summer Program Staff
Professor Douglas Ernie
Jenny Parker Program Assistant
Professor Bethanie Stadler
2005 Summer Program Abstracts
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- Participant: Eric Rust
Project: SPICE ++ A Circuit Simulation Software.
Home University: (Seattle University, Seattle, WA 98122)
Faculty: Jaijeet Roychowdhury
Simulation Program with Integrated Circuit Emphasis (SPICE) has become the standard for electrical circuit simulation. However, with technology increasing at an exponential rate, flaws with SPICE have become evident. One simple but very inefficient property of SPICE is that its algorithms rely on each other to execute the program – making it very time consuming and difficult to enact changes in the code. To solve this problem, we are constructing a new program called SPICE ++. The benefits of SPICE ++ is that it is modular in nature, making it easy to add future characteristics to the individual algorithms. SPICE ++ promises to simplify the way circuit designers approach electrical simulations. This allows for valuable resources to be spent on more pressing issues.
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- Participant: Yifei Huang
- Abstract: This article reports on the integration of nano circuit interconnects using electroless deposition. Certain types of electroless deposition baths, such as gold and copper, are autocatalytic. Exploiting this fact, we created patterned seed catalyst deposits of gold on electret substrate by first creating a charge pattern using electric nano contact printing. Electric nano contact printing employs a flexible patterned electrode to induce a charge distribution pattern on the electret substrate. The charge patterned substrate is then used to direct gas phase assembly of gold nanoparticles. The assembled structure is then integrated using electroless deposition baths. Using this method, we have demonstrated successful integration for 1 um lines with 1 um pitch.
- Participant: Yifei Huang
Participan: Ryan Field
Project: SImulation of Thermal Fluctuations in Exchange Coupled Composite Media
Mentor: Randall Victora
Abstract – The effects of thermal fluctuations on magnetic particles are explored. Discussion begins with the case of a single magnetically hard particle and a comparison with the work of W. F. Brown. The computer model consists of numerically integrating the Landau-Lifshitz-Gilbert equation with consideration for random thermal fields. After analyzing the single hard particle case, the thermal model is then applied to the case of an exchange coupled composite configuration. The results of these simulations are then analyzed and compared to those of a single hard particle. The attempt frequencies for the composite media are found to have a consistent trend with regard to the corresponding single particle attempt frequencies.
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Participant: Jakub Szefer
Project: Self-Assembly of FePt Nanoparticles for Patterned Magnetic Recording Media
Advisor: Prof. Jian-Ping Wang
Current recording media, based on magnetic thin films, which are used in data storage are approaching areal density limit and new technologies which could offer higher data storage capacities need to be developed. Patterned magnetic recording media have been proposed as basis for future data storage technologies, which could offer areal densities as high as 1 Tbit/in2. To achieve the high areal density, materials such as the FePt nanoparticles could be used as the building blocks of the patterned media. The objective of the research was to explore solution phase self-assembly of the FePt nanoparticles as well as to perform calculations of the interaction energies which would control the self-assembly of the nanoparticles in a vacuum. Results obtained indicate the feasibility of using an assembly of gas-phase prepared ordered FePt nanoparticles as basis for patterned magnetic recording media. Additionally, calculations of interaction energies between FePt nanoparticles suggest attainability of an repeating pattern of nanoparticles by performing self-assembly in vacuum. The insights obtained through this research should assist in guiding future investigations into methods for creating patterned magnetic recording media from self-assemblies of FePt nanoparticles.
- Participant: Arthur Ken Kuehl
Fabrication of Metallic Microparticles for Use in Drug Delivery Studies
Home University: The University of Arizona
Mentor: Prof. Stephen Campbell, Electrical Engineering,
Novel drug carrying particles are essential in establishing the most efficient delivery possible. Most current particles are polymeric in nature, but metallic particles could have major advantages over polymeric carriers. This project focused on the fabrication of metallic microparticles for use in biomedical research, specifically for research in treating cancer. To produce the particles, photolithographic and electron-beam evaporation processes were used to pattern silicon wafers and deposit metal onto them, respectively. The wafers were coated with a phosphosilicate glass (PSG) layer, which was subsequently covered with low-stress silicon nitride (SiN). The nitride layer was patterned and coated with layers of chrome and gold which were then lifted resulting in four different shapes: a filled circle, a circular ring, a solid rectangle and a rectangular ring. After patterning, the PSG was etched, releasing the metallic particles on nitride bases. These particles were then examined using an Atomic Force Microscope (AFM) to characterize their mechanical properties..
Participant: Laura Vertatschitsch
Project: Biological Significance of a Novel Biclustering Technique on Genetic Expression Data
Mentor: Ahmed Tewfik
Unlocking the complexity of a living organism’s biological processes, functions, and genetic network is vital in learning how to improve the health of humankind. Genetic analysis, especially biclustering, is a significant key. Learning how genes function together in groups, how they regulate under different conditions, and what proteins created by genes trigger certain biological processes will pave new pathways for genetic engineering and disease therapy. This experiment analyzes one such biclustering technique that combs over a gene expression matrix to find subgroups of genes whose expression levels stay constant or increase over a subgroup of conditions or samples, otherwise known as coherent evolution. This biclustering technique was applied to an S. cervisiae, or yeast, genetic expression data matrix. The biclustering was again performed on the same initial matrix two more times, each with selected genes omitted with the intent to increase the biological correlation relationship of the genes in the resultant biclusters. The final results were analyzed using a categorized system of known protein functional annotation from the yeast genome to find the biological significance of the sub-matrices detected by the algorithm.
Project: Power Flow Simulation in MATLAB
Prof. Bruce Wollenberg
Using the Newton-Raphson power flow method, MATLAB can be used to simulate power flow and conduct security analyses in large distribution networks. Previously written code was improved upon to include transformer tap changing logic and the ability to solve from a previous solution. This improved algorithm was then integrated into a security analysis program and several test cases were examined.
Participant: Yanhua Deng
Project: Low Loss Over-Moded ptical Waveguide
Mentor: Anand Gopinath
Studies on the structure slab-coupled optical waveguide laser, SCOWL, have suggested its advantages in performance and in a variety of applications. SCOWL, with its large dimensions, which is a multi-moded structure that can be operated as single-moded, has shown desirable characteristics such as low loss and high coupling efficiency. Through the investigation of InP-InGaAsP SCOWL using BeamProp simulations, it has been demonstrated that it is possible to have a low loss over-moded optical waveguide. Using similar structure as SCOWL, a new low loss over-moded optical waveguide in AlGaAs-GaAs is designed and studied. This new over-moded waveguide has shown better performance than the single-moded waveguide that is used for an optical modulator.
Participant: Matthew Lamparter
Project: Power Electronics: An Undergraduate Viewpoint
Mentor: Ned Mohan
Power electronics is a subject that many electrical engineering students do not encounter until their final year of study, despite its tremendous impact on our world and our dependence upon this area of electrical engineering for industrial, commercial and residential purposes. This project served to evaluate several of the materials used to teach this subject at the University of Minnesota, and to provide feedback on the effectiveness of the materials. Specifically, all of the power electronics laboratories for the course were completed and suggestions were made for the laboratory manual in order to make the directions easier to understand and increase the student benefit from completing the laboratories. In addition, Professor Ned Mohan’s textbook, First Course on Power Electronics, was proofread while in the process of being updated. A stand-alone DC-DC converter circuit was also designed from the existing power-pole board used in the laboratories. This circuit was designed to benefit those power electronics students who would otherwise not have the hands-on experience with the converter without taking the optional laboratory.
Participant: Terence Magno
Project: Coded Excitation Waveform Design for Ultrasound Elastography
Home University: The Cooper Union
Advisor: Dr. Emad Ebbini
Grad Student Mentor: Dalong Liu
Ultrasound elastography is an exciting new technique for determining the material properties of tissue in vivo. Nominally, the technique facilitates the visualization of elasticity information in target tissue regions, introducing a more quantitative dimension to diagnostic ultrasound imaging. This supersedes conventional ultrasound systems designed mainly for qualitative imaging. In elastography, the use of chirp-coded excitations has been shown to provide high SNR, increase spatial resolution, and reduce decorrelation noise caused by tissue strain. However, their efficiency in imaging tissues of various properties is yet to be fully quantified. In this project, the student was involved in evaluating, characterizing, and optimizing different chirp-coded imaging waveforms. “Pushing” and imaging waveforms – both generated by a specially designed IST (Integrated SWEI Transducer) – were applied on tissue-mimicking samples of varying Young’s modulus. The virtues of the acquired data were gauged according to elastographic figures of merit, such as SNRS (sonographic SNR), SNRr (correlation SNR), ρ (correlation coefficient), and s2CRLB (Cramér-Rao lower bound on estimator variance).
Participant: Christine E. Nishiyama
Project: Investigation of High Frequency Chest Compression and Its Effectiveness in Cystic Fibrosis Therapy
Home Institution:University of San Diego
Advisor: Prof. James E. Holte (Department of Electrical and Computer Engineering), Dr. Warren J. Warwick (Department of Pediatrics)
Graduate Student Advisor: Yong Wan Lee
High frequency chest compression (HFCC) is a technique currently used for treating the acquired pulmonary disease in patients with cystic fibrosis (CF). It provides chest wall compression and produces high frequency oscillation in the airways. Recent studies have shown that the triangular oscillation pulse provides the most airflow (L/s). The velocity airflow is assumed to be the most effective waveform to remove mucus. A new prototype of the triangular waveform called the InCourage System™ (ICS machine), has been developed with varying frequency and pressure settings. Our goal is to investigate the variable frequency and oscillation technique of HFCC ICS and its effects on airflow, pressure, energy and power among other factors. Because acquired pulmonary disease is a major cause of disability and death, there is a major outbreak in the research interest for CF treatment as it has shown that delaying development of lung disease will and significantly increases life expectancy of patients. HFCC may be the most effective preventative therapy.
Participant: Johangel Figueroa
Program:NINN-REU
Home Institution: University of Puerto Rico
Faculty Mentor:Dr. M. Fidaleo, Department of Food Science and Technology, University of Tuscia, Italy
Project: Model Micro-channels for the Study of Aerobic, Nano-porous Biocatalytic Latex Coatings
Embedding bacteria in a nano-porous, self-assembled polymer coating would create highly reactive biocatalysts useful in micro-channel reactors. Our model system is a ~ 65 µm thick nano-porous acrylate/vinyl acetate latex coating containing the bacterium Gluconobacter oxydans. G. oxydans is a rod shaped obligate aerobe which can carry out many oxidations, such as D-sorbitol to L-sorbose, using membrane bound dehydrogenases. This oxidation is non-growth associated, oxygen dependant and can be measured using HPLC. Bioconversion of D-sorbitol to L-sorbose was initially studied using 2.5 cm2 latex coatings in a non-growth media. A high reaction rate per surface area of coating was observed. Model micro-reactor channels (~ 500 µm to 1000 µm deep) where designed. Microscopic images of a nano-porous coating in ~ 450 µm wide channels where obtained. A macro-channel, 10 mm wide, where coated strips of G. oxydans can be tested was developed in order to measure the reaction rates accurately with HPLC. The reaction rates obtained in this larger channel, with a three-phase bubbly slug flow, will help us predict biocatalytic activity of G. oxydans in < 500 µm micro-channels, and aid us in the engineering of nano-porous biocatalytic coatings for micro-channel bioreactors.
