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Vector Magneto-Optical Generalized Ellipsometry For Determining Magneto-Optical Properties Of Thin Films, Chad Briley 2016 University of Nebraska-Lincoln

Vector Magneto-Optical Generalized Ellipsometry For Determining Magneto-Optical Properties Of Thin Films, Chad Briley

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Modern growth techniques allow for highly complex nano scale thin films to be created. These new films possess highly anisotropic properties structurally, optically, and magnetically that are significantly different from that of their bulk counterparts and must be accurately characterized in order to optimize desired properties for applications in next generation devices. Current magnetometry techniques focus on high symmetry characterization, namely in and out of the sample plane, and therefore do not possess the capabilities to fully explore these anisotropic properties without complicated setups and multiple sample manipulations. The author describes a setup that combines generalized ellipsometry with an octu-pole ...


Photoluminescence Studies Of Amorphous Boron Carbide And Tungsten Diselenide Thin Films, David M. Allendorfer 2016 University of Nebraska - Lincoln

Photoluminescence Studies Of Amorphous Boron Carbide And Tungsten Diselenide Thin Films, David M. Allendorfer

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

For many years scientists and engineers have been researching semi-conducting materials for use in a broad array of electronic devices. With the growing demand for faster, smaller and more efficient electronics, new materials must be characterized and their properties quantified. The focus of this thesis is to develop a system to measure photoluminescence in opto-electronic materials. Photoluminescence measurements are important because it can give researchers valuable information about a material’s band structure. This thesis begins by presenting the carrier recombination mechanisms and how they apply to photoluminescence. A system was developed to measure photoluminescence spectroscopy. This system was tested ...


Design, Fabrication And Measurement Of A Plasmonic Enhanced Terahertz Photoconductive Antenna, Nathan Matthias Burford 2016 University of Arkansas, Fayetteville

Design, Fabrication And Measurement Of A Plasmonic Enhanced Terahertz Photoconductive Antenna, Nathan Matthias Burford

Theses and Dissertations

Generation of broadband terahertz (THz) pulses from ultrafast photoconductive antennas (PCAs) is an attractive method for THz spectroscopy and imaging. This provides a wide frequency bandwidth (0.1-4 THz) as well as the straightforward recovery of both the magnitude and phase of the transmitted and/or reflected signals. The achieved output THz power is low, approximately a few microwatts. This is due to the poor conversion of the femtosecond laser used as the optical pump to useable current inside the antenna semiconducting material. The majority of THz power comes from the photocarriers generated within ~ 100 nm distance from the antenna ...


Investigation Of The Optical Properties Of Pbse/Pbx Nanocrystals For Photodetector Applications, Haley Ann Morris 2016 University of Arkansas, Fayetteville

Investigation Of The Optical Properties Of Pbse/Pbx Nanocrystals For Photodetector Applications, Haley Ann Morris

Theses and Dissertations

Lead selenide and lead selenide/lead sulfide core/shell nanocrystals were investigated for use in near infrared photodetectors. A colloidal synthesis method was used for both the core and core/shell configurations. The lead sulfide shell was examined in order to mitigate oxidation of the nanoparticle surface. Absorbance and photoluminescence spectra were measured at room temperature and 77 K, respectively. Transmission electron microscopy images were also obtained to confirm crystallography and size. Bulk lead selenide was simulated in WIEN2k utilizing the linear-augmented plane wave method of solving density functional theory to better understand the electronic structure of PbSe. The crystal ...


Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix 2016 University of Arkansas, Fayetteville

Interactive Physics And Characteristics Of Photons And Photoelectrons In Hyperbranched Zinc Oxide Nanostructures, Garrett Edward Torix

Theses and Dissertations

As is commonly known, the world is full of technological wonders, where a multitude of electronic devices and instruments continuously help push the boundaries of scientific knowledge and discovery. These new devices and instruments of science must be utilized at peak efficiency in order to benefit humanity with the most advanced scientific knowledge. In order to attain this level of efficiency, the materials which make up these electronics, or possibly more important, the fundamental characteristics of these materials, must be fully understood. The following research attempted to uncover the properties and characteristics of a selected family of materials. Herein, zinc ...


Development Of Breast Tissue Phantoms For Enhanced Terahertz Imaging Utilizing Microdiamond And Nano-Onion Particles, Alec Walter 2016 University of Arkansas, Fayetteville

Development Of Breast Tissue Phantoms For Enhanced Terahertz Imaging Utilizing Microdiamond And Nano-Onion Particles, Alec Walter

Electrical Engineering Undergraduate Honors Theses

This thesis presents the work performed to develop tissue phantoms and a contrast agent that will be used in future research of terahertz time-domain imaging of breast tumor margins. Since an excised breast tumor can contain healthy fibrous and fatty tissues along with invasive ductal carcinoma (IDC), three phantom materials were developed. Solid phantom materials were made by using TX151 to solidify water in order to tune the refractive index and absorption coefficient of the fibrous tissue phantom and IDC phantom to the properties of freshly excised breast tissue. Various amounts of olive oil were added to the water prior ...


Time Domain Analysis Of Terahertz Photoconductive Antennas Using High- Frequency Structure Simulator (Hfss), David Carballo 2016 University of Arkansas, Fayetteville

Time Domain Analysis Of Terahertz Photoconductive Antennas Using High- Frequency Structure Simulator (Hfss), David Carballo

Electrical Engineering Undergraduate Honors Theses

In this thesis, an in-depth guide and description on how to model and perform frequency and mainly time domain analysis of a THz photoconductive antenna using HFSS will be presented. The main purpose of this thesis is to master and document the procedures for transient domain analysis in HFSS to fill the lack of documentation about this topic. Moreover, another goal is to compare the results from HFSS with the ones from another program, COMSOL (conducted by a PhD student), in order to validate the correctness of the procedure.

From this thesis, it can be concluded that in order to ...


A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox 2016 University of Maine

A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox

Electronic Theses and Dissertations

We explored the capabilities of additive manufacturing using a photo-cured jetted material 3D printer to manufacture a milli-microfluidic device with direct application in microalgae Dunaliella sp growth and intracellular compounds biosynthesis tests. A continuous microbioreactor for microalgae culture was CAD designed and successfully built in 1 hour and 49 minutes using black photopolymer cured by UV and a support material. The microreactor was made up of 2 parts including the bioreactor itself and a microchannel network for culture media fluids and microalgae. Both parts were assembled to form a single unit. Additional optical and auxiliar components were added. An external ...


Frequency Tunable Antennas And Surface Microwave Imaging System Using Microfluidic Reconfiguration Techniques, Abhishek Dey 2016 University of South Florida

Frequency Tunable Antennas And Surface Microwave Imaging System Using Microfluidic Reconfiguration Techniques, Abhishek Dey

Graduate Theses and Dissertations

Reconfigurable radio frequency (RF) devices are attractive for miniaturization of wireless components and systems by handling functionality of multiple distinct devices. Existing reconfiguration techniques rely on device loadings with semiconductor diodes, ferrite/ferroelectric materials, and microelectromechanical system (MEMS) switches and capacitors. However, it is well-recognized that these techniques cannot fully address important system metrics such as high efficiency, wide frequency tuning range, high power handling capability and cost. Therefore, novel alternative techniques are highly desirable to advance the state of the art in reconfigurable RF devices. The aim of this dissertation is to investigate the novel concept of microfluidically loaded ...


Rain Attenuation Effects On Signal Propagation At W/V-Band Frequencies, Nadine Daoud 2016 University of New Mexico

Rain Attenuation Effects On Signal Propagation At W/V-Band Frequencies, Nadine Daoud

Electrical and Computer Engineering ETDs

The current frequency spectrum congestion in space is begging for the exploration and utilization of a new range of frequencies. The W/V-band Terrestrial Link Experiment (WTLE) project run jointly by AFRL, NASA and the University of New Mexico, focuses on using higher frequencies for satellite communications, more precisely, at 72 GHz and 84 GHz.

In this thesis, the rain effect on the propagating signal is studied. First, instantaneous comparisons between the experiment and two different models, the ITU-R and the Siva-Mello, is presented. Second, the WTLE link was analyzed statistically over a period of approximately 10 months, and the ...


Optimal And Miniaturized Strongly Coupled Magnetic Resonant Systems, Hao Hu 2016 Florida International University

Optimal And Miniaturized Strongly Coupled Magnetic Resonant Systems, Hao Hu

FIU Electronic Theses and Dissertations

Wireless power transfer (WPT) technologies for communication and recharging devices have recently attracted significant research attention. Conventional WPT systems based either on far-field or near-field coupling cannot provide simultaneously high efficiency and long transfer range. The Strongly Coupled Magnetic Resonance (SCMR) method was introduced recently, and it offers the possibility of transferring power with high efficiency over longer distances. Previous SCMR research has only focused on how to improve its efficiency and range through different methods. However, the study of optimal and miniaturized designs has been limited. In addition, no multiband and broadband SCMR WPT systems have been developed and ...


Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed 2016 University of Dayton

Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed

Monish R. Chatterjee

The effects of turbulence on anisoplanatic imaging are often modeled through the use of a sequence of phase screens distributed along the optical path. We implement the split-step wave algorithm to examine turbulence-corrupted images.


Directional Ringlet Intensity Feature Transform For Tracking, Evan Krieger, Paheding Sidike, Theus H. Aspiras, Vijayan K. Asari 2016 University of Dayton

Directional Ringlet Intensity Feature Transform For Tracking, Evan Krieger, Paheding Sidike, Theus H. Aspiras, Vijayan K. Asari

Vijayan K. Asari

The challenges existing for current intensity-based histogram feature tracking methods in wide area motion imagery include object structural information distortions and background variations, such as different pavement or ground types. All of these challenges need to be met in order to have a robust object tracker, while attaining to be computed at an appropriate speed for real-time processing. To achieve this we propose a novel method, Directional Ringlet Intensity Feature Transform (DRIFT), that employs Kirsch kernel filtering and Gaussian ringlet feature mapping. We evaluated the DRIFT on two challenging datasets, namely Columbus Large Image Format (CLIF) and Large Area Image ...


Histogram Of Oriented Phase (Hop): A New Descriptor Based On Phase Congruency, Hussin Ragb, Vijayan K. Asari 2016 University of Dayton

Histogram Of Oriented Phase (Hop): A New Descriptor Based On Phase Congruency, Hussin Ragb, Vijayan K. Asari

Vijayan K. Asari

In this paper we present a low level image descriptor called Histogram of Oriented Phase based on phase congruency concept and the Principal Component Analysis (PCA). Since the phase of the signal conveys more information regarding signal structure than the magnitude, the proposed descriptor can precisely identify and localize image features over the gradient based techniques, especially in the regions affected by illumination changes. The proposed features can be formed by extracting the phase congruency information for each pixel in the image with respect to its neighborhood. Histograms of the phase congruency values of the local regions in the image ...


Thermoelectric Magnetohydrodynamic Effects In Solidification Processes, Andrew Kao, Koulis Pericleous, Peter Lee, Biao Cai, Jianrong Gao 2016 University of Manchester

Thermoelectric Magnetohydrodynamic Effects In Solidification Processes, Andrew Kao, Koulis Pericleous, Peter Lee, Biao Cai, Jianrong Gao

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Negative Index In Chiral Metamaterials Under Conductive Loss And First-Order Material Dispersion Using Lorentzian, Condon And Drude Models, Monish Ranjan Chatterjee, Tarig A. Algadey 2016 University of Dayton

Negative Index In Chiral Metamaterials Under Conductive Loss And First-Order Material Dispersion Using Lorentzian, Condon And Drude Models, Monish Ranjan Chatterjee, Tarig A. Algadey

Electrical and Computer Engineering Faculty Publications

Emergence of negative index (NIM) in chiral materials with conductive loss using standard dispersive models is reported. Positive and negative phase and group indices are realized as expected for NIM behavior for sidebands with opposite polarities.


Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed 2016 University of Dayton

Anisoplanatic Electromagnetic Image Propagation Through Narrow Or Extended Phase Turbulence Using Altitude-Dependent Structure Parameter, Monish Ranjan Chatterjee, Ali Mohamed

Electrical and Computer Engineering Faculty Publications

The effects of turbulence on anisoplanatic imaging are often modeled through the use of a sequence of phase screens distributed along the optical path. We implement the split-step wave algorithm to examine turbulence-corrupted images.


Optimization Of The Bowtie Gap Geometry For A Maximum Electric Field Enhancement, Tsenguun Byambadorj 2016 Marquette University

Optimization Of The Bowtie Gap Geometry For A Maximum Electric Field Enhancement, Tsenguun Byambadorj

Master's Theses (2009 -)

Optimization of the geometry of a metallic bowtie gap at radio frequency is presented in this thesis. Since the design and fabrication of a plasmonic device (nanogap) at nanoscale is challenging, the results of this study can be used to estimate the best design parameters for nanogap structure. The geometry of the bowtie gap including gap size, tip width, metal thickness, and tip angle are investigated at macroscale to find the maximum electric field enhancement across the gap. This thesis focuses on the simulation portion of a work that consists of experimental and simulation platforms. The simulation platform is created ...


Analysis Of Interference Between Electromagnetic Articulography And Electroglottograph Systems, Kelly Vonderhaar 2016 Marquette University

Analysis Of Interference Between Electromagnetic Articulography And Electroglottograph Systems, Kelly Vonderhaar

Master's Theses (2009 -)

Electromagnetic Articulography (EMA) has become an integral tool for researchers and clinicians who seek to characterize speech kinematics. The position and orientation of the articulators – which include the jaw, lips, and tongue – are recorded by attaching sensors to the articulators and tracking the movement of the sensors through an electromagnetic field. This has been used by researchers and clinicians to better understand dysarthria and synthesize speech, among other applications. Another speech tool, electroglottography (EGG), is used to analyze the movement of the vocal folds during speech production. This is achieved by measuring the time variation of the contact of the ...


Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani 2016 Air Force Institute of Technology

Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani

Theses and Dissertations

Achieving worldwide alternatives to GPS is a challenging engineering problem. Current GPS alternatives often suffer from limitations such as where and when the systems can operate. Navigation using the Earth's magnetic anomaly field, which is globally available at all times, shows promise to overcome many of these limitations. We present a navigation filter which uses the Earth's magnetic anomaly field as a navigation signal to aid an inertial navigation system (INS) in an aircraft. The filter utilizes highly-accurate optically pumped cesium (OPC) magnetometers to make scalar measurements of the Earth's magnetic field and compare them to a ...


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