Rapid Prototyping Of Nanostructures With Electron Beam Induced Processing,
2020
University of Kentucky
Rapid Prototyping Of Nanostructures With Electron Beam Induced Processing, Samaneh Esfandiarpour
Theses and Dissertations--Electrical and Computer Engineering
Focused electron beam induced processing (FEBIP) is a nano-scale fabrication technique that allows the direct deposition of functional materials. However, it suffers from significant drawbacks, such as high cost, low speed, unavailable precursors for many materials and low purity of deposits. Liquid-phase focused electron beam induced processes (LP-FEBIP) are being investigated due to the potential benefits over the gas phase technique. In this method, deposition or etching occurs at the interface between a substrate and a bulk liquid. In this work, electron beam induced deposition of copper nanostructures from aqueous solutions of copper sulfate is demonstrated. The addition of sulfuric …
Parallelized X-Ray Tracing With Gpu Ray-Tracing Engine,
2020
University of Central Florida
Parallelized X-Ray Tracing With Gpu Ray-Tracing Engine, Joseph Ulseth
Electronic Theses and Dissertations, 2020-2023
X-ray diffraction tomography (XDT) is used to probe material composition of objects, providing improved contrast between materials compared to conventional transmission based computed tomography (CT). In this work, a small angle approximation to Bragg's Equation of diffraction is coupled with parallelized computing using Graphics Processing Units (GPUs) to accelerate XDT simulations. The approximation gives rise to a simple yet useful proportionality between momentum transfer, radial distance of diffracted signal with respect to incoming beam's location, and depth of material, so that ray tracing may be parallelized. NVIDIA's OptiX ray-tracing engine, a parallelized pipeline for GPUs, is employed to perform XDT …
Fluorescence Microscopy With Tailored Illumination Light,
2020
University of Central Florida
Fluorescence Microscopy With Tailored Illumination Light, Jialei Tang
Electronic Theses and Dissertations, 2020-2023
Fluorescence microscopy has long been a valuable tool for biological and medical imaging. Control of optical parameters such as the amplitude, phase, polarization and propagation angle of light gives fluorescence imaging great capabilities ranging from single molecule imaging to long-term observation of living organisms. While numerous fluorescence imaging techniques have been developed over the past decades, there is always an inevitable tradeoff among the spatial resolution, imaging speed, contrast, photodamage and the total cost when it comes to choose the appropriate microscope. A main goal of my dissertation research is to develop state-of-the-art microscope systems that exhibit unprecedented performance in …
Nonlinear Optical Mechanisms In Semiconductors And Enhanced Nonlinearities At Epsilon-Near-Zero,
2020
University of Central Florida
Nonlinear Optical Mechanisms In Semiconductors And Enhanced Nonlinearities At Epsilon-Near-Zero, Sepehr Ahmadzadeh Benis
Electronic Theses and Dissertations, 2020-2023
Light does not interact with itself in linear optical materials. Such interactions occur only in non-linear optical (NLO) materials and typically require high intensity optical beams to be signifi-cant. The ever-increasing role of NLO, where intense light may change the properties of the me-dium, has created a pressing demand to invent materials for achieving more efficient light-light and light-matter interaction due to their potential capacity to augment and possibly replace cur-rent technologies with more efficient devices. There are numerous applications of NLO devices in fundamental science, technology, health, and defense such as all-optical computation and sig-nal processing, ultrashort laser technology, …
Iterative Optical Diffraction Tomography For Reconstruction Of Multiply-Scattering Objects,
2020
University of Central Florida
Iterative Optical Diffraction Tomography For Reconstruction Of Multiply-Scattering Objects, Shengli Fan
Electronic Theses and Dissertations, 2020-2023
As a label-free, non-destructive, high-resolution, and quantitative imaging technique, optical diffraction tomography (ODT) has been widely used to image biological samples and microstructures, such as cells, tissues, and optical fibers. The refractive-index (RI) distribution of an object is reconstructed from multi-view measurements of diffracted fields emerging from the object. Typical ODT setups include the object rotating configuration (ORC) and the illumination scanning configuration (ISC). One major limitation of ODT is that it is only applicable to weakly-scattering objects. In this dissertation, novel methods have been developed to overcome the reconstruction difficulty caused by multiple scattering, so as to extend ODT …
Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure,
2020
West Virginia University
Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure, Catherine G. O'Hearn
Graduate Theses, Dissertations, and Problem Reports (ETD)
There have been many great advances in the generation and manipulation of optics in the visible and near infrared (IR) range over the past decade. This is largely due to plasmonic enhancement, which has led to new technology in biosensing and molecule detection, solid-state lighting, and solar energy harvesting. The field of plasmonics uses quanta of plasma oscillations, plasmons, formed from the interaction between electromagnetic radiation and free electrons to enhance optical near field magnitudes. However, there is still a large region of the electromagnetic spectrum, covering the mid-infrared (MIR) and terahertz (THz) regions, ranging from 3 μm to 1 …
Parametric Optimization Of Visible Wavelength Gold Lattice Geometries For Improved Plasmon-Enhanced Fluorescence Spectroscopy,
2020
West Virginia University
Parametric Optimization Of Visible Wavelength Gold Lattice Geometries For Improved Plasmon-Enhanced Fluorescence Spectroscopy, Casey A. Norville
Graduate Theses, Dissertations, and Problem Reports (ETD)
The exploitation of spectro-plasmonics will allow for innovations in optical instrumentation development and the realization of more efficient optical biodetection components. Biosensors have been shown to improve the overall quality of life through real-time detection of various antibody-antigen reactions, biomarkers, infectious diseases, pathogens, toxins, viruses, etc. has led to increased interest in the research and development of these devices. Further advancements in modern biosensor development will be realized through novel electrochemical, electromechanical, bioelectrical, and/or optical transduction methods aimed at reducing the size, cost, and limit of detection (LOD) of these sensor systems. One such method of optical transduction involves the …
Design And Development Of Fiber Bragg Grating Sensor For Detecting Of Hydrogen Gas In Transformer Oil,
2020
Universiti Malaya
Design And Development Of Fiber Bragg Grating Sensor For Detecting Of Hydrogen Gas In Transformer Oil, Mohd Raffi Samsudin
Student Works (2020-2029)
Hermetically sealed oil-immersed transformers are the key to electricity distribution networks. They are also one of the most expensive facilities in the electricity supply network. Immediate replacement is expected for this type of transformer upon failure because it is directly connected to the customer. Transformer oil acts as insulation, coolant and condition indicator. To date, there is no economical real-time monitoring system available to monitor the transformer oil condition. Therefore, there is a need to develop a cheap, non-intrusive and non-electrical sensor to monitor the health of the transformer by measuring the amount of dissolved hydrogen gas in oil, which …
Improving The Efficiency Of Planar Goubau Line And Goubau-Line-Based Endfire Antenna,
2020
Northern Illinois University
Improving The Efficiency Of Planar Goubau Line And Goubau-Line-Based Endfire Antenna, Sreelakshmi Radhakrishnan
Graduate Research Theses & Dissertations
This thesis presents the use of two dielectric layers in a planar Goubau line (PGL) to improve its transmission efficiency compared to the existing single-layer models, which is less than 70% efficient at lower frequencies up to 5 GHz. Further, as an extension of the thesis, the possibility of obtaining directive radiation pattern with radiation efficiency greater than 89.6% using a Goubau-line-based antenna is studied. While none of the existing Goubau-line-based antennas are able to obtain an endfire pattern with radiation efficiency of above 80%, the proposed model utilizes stubs that are periodically attached to the main line of length …
Multi-Physics-Based Approach To Active Microwave Thermography,
2020
Missouri University of Science and Technology
Multi-Physics-Based Approach To Active Microwave Thermography, Seyed Ali Mirala
Doctoral Dissertations
“The goal of this work is to advance a novel nondestructive testing (NDT) method for controlled, rapid, and effective inspection of a structure through the integration of microwave NDT and thermography, referred to as Active Microwave Thermography (AMT). In AMT, the structure under test is exposed to microwave radiation and the thermal profile of the structure is monitored via a thermal camera in order to obtain desired information regarding the structure. This new technique is applicable across a wide range of NDT needs including detection of voids, delamination, water ingress, debonding, and cracks in numerous structures such as carbon fiber …
System Efficient Esd Design Concept For Soft Failures,
2020
Missouri University of Science and Technology
System Efficient Esd Design Concept For Soft Failures, Giorgi Maghlakelidze
Doctoral Dissertations
"This research covers the topic of developing a systematic methodology of studying electrostatic discharge (ESD)-induced soft failures. ESD-induced soft failures (SF) are non-destructive disruptions of the functionality of an electronic system. The soft failure robustness of a USB3 Gen 1 interface is investigated, modeled, and improved. The injection is performed directly using transmission line pulser (TLP) with varying: pulse width, amplitude, polarity. Characterization provides data for failure thresholds and a SPICE circuit model that describes the transient voltage and current at the victim. Using the injected current, the likelihood of a SF is predicted. ESD protection by transient voltage suppressor …
Evolution Of Two-Element Directive Antennas,
2020
Georgia Southern University
Evolution Of Two-Element Directive Antennas, Tyler J. Mcpherson
College of Graduate Studies: Theses & Dissertations
The classic Yagi antenna is often utilized to provide directional radiation. Many facets of the Yagi antenna can be improved. This thesis focuses on the evolution of the two-element directive antennas, such as the Yagi antenna, in three ways. First, the inter-element spacing is reduced beyond those previously mentioned in literature. Next, an electrically-small version of the two-element Yagi with extremely close inter-element spacing is explored with a linear polarized and a circularly polarized configuration. Finally, further analysis of a wideband, circularly polarized, two-element, directive antenna with standard interelement spacing is performed.
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering,
2020
Old Dominion University
Effect Of Layer Thickness On Structural, Morphological And Superconducting Properties Of Nb3Sn Films Fabricated By Multilayer Sequential Sputtering, M. N. Sayeed, U. Pudasaini, C. E. Reece, G. V. Eremeev, H. E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
Superconducting Nb3Sn films can be synthesized by controlling the atomic concentration of Sn. Multilayer sequential sputtering of Nb and Sn thin films followed by high temperature annealing is considered as a method to fabricate Nb3Sn films, where the Sn composition of the deposited films can be controlled by the thickness of alternating Nb and Sn layers. We report on the structural, morphological and superconducting properties of Nb3Sn films fabricated by multilayer sequential sputtering of Nb and Sn films on sapphire substrates followed by annealing at 950 °C for 3 h. We have investigated the …
Optical Spectroscopy And Theoretical Modelling Of Carrier Dynamics In Group-Iv Alloy Quantum Dots,
2020
Virginia Commonwealth University
Optical Spectroscopy And Theoretical Modelling Of Carrier Dynamics In Group-Iv Alloy Quantum Dots, Rahnuma Rahman
Theses and Dissertations
In recent years, Ge1−xSnx alloy quantum dots (QDs) have attracted significant interest due to their potential applications in photodetectors and light emitting devices in visible to mid IR spectral range and compatibility with silicon based platforms. While bulk Ge is an indirect bandgap semiconductor (0.66 eV), direct transitions can be made possible by incorporation of α-Sn at concentrations of ~10%, which however lowers the bandgap. Utilizing quantum confinement by reducing the size to below the Bohr radius also promotes direct transitions and more importantly increases the fundamental transition energies in GeSn alloy QDs, making them suitable for …
Sparsity Constrained Regression For High-Speed Signal Integrity Modeling,
2019
Missouri University of Science and Technology
Sparsity Constrained Regression For High-Speed Signal Integrity Modeling, Jiacheng Zhuo, Jiayi He, Zurab Kiguradze, Bhyrav Mutnury, James Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
High-speed signal integrity (SI) modeling usually involves modeling non-linear subsystems. Traditional approaches like response surface modeling (RSM), artificial neural networks (ANN) and support vector machine (SVM) suffer from two major issues. Either they don't scale well when the number of dimensions or variables increase in the non-linear model, or they are sensitive to the initial training data used to create the models. For example: RSM approach requires large design of experiments (DoE) when the number of variables increase. With ANN, the designer has to spend a lot of time tuning or optimizing the hyperparameters. In this paper, a new approach …
Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity,
2019
University of Arkansas, Fayetteville
Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo
Graduate Theses and Dissertations
Noble metal nanoparticles and two-dimensional (2D) transition metal dichalcogenide (TMD) crystals offer unique optical and electronic properties that include strong exciton binding, spin-orbital coupling, and localized surface plasmon resonance. Controlling these properties at high spatiotemporal resolution can support emerging optoelectronic coupling and enhanced optical features. Excitation dynamics of these optical properties on physicochemically bonded mono- and few-layer TMD crystals with metal nanocrystals and two overlapping spherical metal nanocrystals were examined by concurrently (i) DDA simulations and (ii) far-field optical transmission UV-vis spectroscopic measurements. Initially, a novel and scalable method to unsettle van der Waals bonds in bulk TMDs to prepare …
High Frequency Ltcc Based Planar Transformer,
2019
University of Arkansas, Fayetteville
High Frequency Ltcc Based Planar Transformer, Adithya Venkatanarayanan
Graduate Theses and Dissertations
As we move towards high power and higher frequency related technology, conventional wire-wound magnetics have their own limitations which has led path to the development of planar based magnetic materials. Nowadays more planar magnetic technology has been employed because it is easier to fabricate them. The planar magnetic is a transformer or an inductor that replaces the wire-wound transformer or inductors which generally uses copper wires. One of the main reasons why we move to planar magnetic technology is its operation at higher frequency which provides higher power density. This study explains in detail about the design and fabrication of …
Exploring Convergence Of Snake Skin-Inspired Texture Designs And Additive Manufacturing For Mechanical Traction,
2019
University of Arkansas, Fayetteville
Exploring Convergence Of Snake Skin-Inspired Texture Designs And Additive Manufacturing For Mechanical Traction, Catherine Sue Tiner
Graduate Theses and Dissertations
This research focuses on the understanding, development, and additive manufacture of a 3D printed snake skin-inspired texture pattern. The design functionalities of snake skin were determined through the study of the snake species Python Regius otherwise known as the ball python. Each scale of a snake has hierarchical texture with hexagonal macro-patterns aligned on the ventral surface of the skin with overriding anisotropic micro textured patterns such as denticulations and fibrils. Using a laser-powder bed fusion (L-PBF) process, 420 stainless steel samples were 3D printed which closely resemble the above described directional texture of natural snake skin. This printed surface …
Performance Enhancement And Characterization Of An Electromagnetic Railgun,
2019
California Polytechnic State University, San Luis Obispo
Performance Enhancement And Characterization Of An Electromagnetic Railgun, Paul M. Gilles
Master's Theses
Collision with orbital debris poses a serious threat to spacecraft and astronauts. Hypervelocity impacts resulting from collisions mean that objects with a mass less than 1g can cause mission-ending damage to spacecraft. A means of shielding spacecraft against collisions is necessary. A means of testing candidate shielding methods for their efficacy in mitigating hypervelocity impacts is therefore also necessary. Cal Poly’s Electromagnetic Railgun was designed with the goal of creating a laboratory system capable of simulating hypervelocity (≥ 3 km/s) impacts. Due to several factors, the system was not previously capable of high-velocity (≥ 1 km/s) tests. A deficient projectile …
Bayesian Optimization For High-Speed Channel Equalization,
2019
Missouri University of Science and Technology
Bayesian Optimization For High-Speed Channel Equalization, Zurab Kiguradze, Nana Dikhaminjia, Mikheil Tsiklauri, Jiayi He, Bhyrav Mutnury, Arun Chada, James Drewniak
Electrical and Computer Engineering Faculty Research & Creative Works
Equalization methods are used to recover the signal attenuated by channel loss. Different optimization algorithms are applied to find the best tap coefficients for each equalization that will improve eye opening and reduce bit error rate. The goal function for most equalization optimization algorithms is to reduce the difference between input and output signals, which is a linear optimization problem and can be solved relatively easily. This indirectly will increase eye height and improve eye diagram. Directly optimizing eye height is a non-linear problem and cannot be solved with analytical method. We are proposing FFE and DFE combined equalization optimization …
