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Ultrafast Mechanisms Of Nonlinear Refraction And Two-Photon Photochromism, Peng Zhao Jan 2016

Ultrafast Mechanisms Of Nonlinear Refraction And Two-Photon Photochromism, Peng Zhao

Electronic Theses and Dissertations

Derived from a material's third-order nonlinearity, nonlinear refraction (NLR) occurs at any wavelength in any material, and may exhibit noninstantaneous dynamics depending on its physical origins. The main subject of this dissertation is to investigate the underlying mechanisms responsible for the NLR response in different phases of matter, e.g. liquids, gases, and semiconductors, by extensively using our recently developed ultrafast Beam Deflection (BD) technique. An additional subject includes the characterization of a novel two-photon photochromic molecule. In molecular liquids, the major nonlinear optical (NLO) response can be decomposed into a nearly instantaneous bound-electronic NLR (Kerr effect), originating from the real …

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Analysis Of Benzopyrenes And Benzopyrene Metabolites By Fluorescence Spectroscopy Techniques, Bassam Al-Farhani Jan 2016

Analysis Of Benzopyrenes And Benzopyrene Metabolites By Fluorescence Spectroscopy Techniques, Bassam Al-Farhani

Electronic Theses and Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are some of the most common and toxic pollutants encountered worldwide. Presently, monitoring is restricted to sixteen PAHs, but it is well understood that this list omits many toxic PAHs. Among the "forgotten" PAHs, isomers with molecular weight 302 are of particular concern due to their high toxicological properties. The chromatographic analysis of PAHs with MW 302 is challenged by similar retention times and virtually identical mass fragmentation patterns. The first original component of this dissertation evolves from a high-resolution spectroscopic approach specifically developed to fulfil this gap. Herein, 4.2 K Laser-Excited Time-Resolved Shpol'skii Spectroscopy (4.2K …

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Fabrication And Characterization Of Spatially-Variant Self-Collimating Photonic Crystals, Jennefir Digaum Jan 2016

Fabrication And Characterization Of Spatially-Variant Self-Collimating Photonic Crystals, Jennefir Digaum

Electronic Theses and Dissertations

Spatially-variant photonic crystals (SVPCs) created using materials having a low refractive index are shown to be capable of abruptly controlling light beams with high polarization selectivity. SVPCs are photonic crystals for which the orientation of the unit cell is controllably varied throughout the lattice to control the flow of light. Multi-photon lithography in a photo polymer was used to fabricate three-dimensional SVPCs that direct the flow of light around a 90 degree bend. The optical performance of the SVPCs was characterized using a scanning optical-fiber system that introduced light onto the input face of a structure and measured the intensity …

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Laser Filament Interaction With Aerosols And Clouds, Cheonha Jeon Jan 2016

Laser Filament Interaction With Aerosols And Clouds, Cheonha Jeon

Electronic Theses and Dissertations

A high powered ultrashort laser pulse can propagate as a diffraction-free self-channeled structure called a filament, created by a combination of nonlinear processes. With its ability to convey extremely high intensity beams to distant targets, many applications such as remote sensing, cloud seeding, and discharge guiding are potentially possible. However, one of the main challenges of outdoor field applications is the laser propagation through the atmosphere where pressure fluctuations and concentrations of aerosols may be present. The rationale behind the work presented in this dissertation is to evaluate the robustness of the filamentation, measure the interaction losses as well as …

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A Comparison Of Sixth Grade Student Achievement In Reading And Mathematics At School Transition Year, Julie Roseboom Jan 2016

A Comparison Of Sixth Grade Student Achievement In Reading And Mathematics At School Transition Year, Julie Roseboom

Electronic Theses and Dissertations

This study contributed information for consideration as school districts determine grade span configuration as part of school design. The problem addressed was the extent to which student achievement may be impacted by the transition from one school to another from fifth to sixth grade in Florida public schools in order to provide data to school policy makers and school district administrators and add to the body of knowledge on the grade level configuration that contributed the most to student achievement in sixth grade. This was a causal-comparative study using quantitative data to analyze student scores at the school level for …

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Design And Engineering Of Ultrafast Amplifier Systems, Benjamin Webb Jan 2016

Design And Engineering Of Ultrafast Amplifier Systems, Benjamin Webb

Electronic Theses and Dissertations

Recently, the design and engineering of ultrafast laser systems have led to an extraordinary increase in laser power and performance which have brought about advances in many fields such as medicine, material processing, communications, remote sensing, spectroscopy, nonlinear optics, and atomic physics. In this work, several ultrafast amplification techniques -- including chirped-pulse amplification (CPA), optical parametric chirped-pulse amplification (OPCPA), and divided-pulse amplification (DPA) -- are described and demonstrated in the design and construction of two ultrafast laser facilities. An existing Ti:Sapphire laser system was completely redesigned with an increased power of 10 TW for experiments capable of generating hundreds of …

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A Hermeneutic Study Of Secondary English Language Arts Teacher Candidates' Writing Instruction Experiences In Esol Methods Courses, Paula Bello Jan 2016

A Hermeneutic Study Of Secondary English Language Arts Teacher Candidates' Writing Instruction Experiences In Esol Methods Courses, Paula Bello

Electronic Theses and Dissertations

The purpose of this hermeneutic study was to understand, describe and interpret secondary English Language Arts (ELA) teacher candidates'(TC) experiences with writing instruction while attending English for Speakers of Other Languages (ESOL) methods courses. The study included a purposeful convenience sample of 15 (fifteen) secondary ELA teacher candidates' (TC) attending 4 (four) different sections in 2 (two) ESOL methods courses. TCs were invited to participate in inquiry driven activities including written reflections in response to a literacy questionnaire, oral interviews responding to open-ended questions and focus/work groups' discussions, which allowed them to reflect about their past and present literacy and …

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Afro-Caribbean Parental Influence: Family Chronicles Of The Educational Journey From Child To Medical Student, Carlene Grant Jan 2016

Afro-Caribbean Parental Influence: Family Chronicles Of The Educational Journey From Child To Medical Student, Carlene Grant

Electronic Theses and Dissertations

Many ethnic groups in the United States have struggled for the opportunity to be identified as an individual group. In academia, these students are often aggregated into a larger category, with little acknowledgment for the difference in their cultural heritage. Along with these cultural differences, Afro-Caribbean parents and their children are met with other challenges in the pursuit of lifelong goals (Sowell, 1978). The decision to become a medical doctor is one that can often not be made alone. Using the framework of Cultural Ecological Theory and Social Construction (Ogbu 1990, 1992; Berger & Luckman, 1991) this study was conducted …

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The Woz Recognizer: A Tool For Understanding User Perceptions Of Sketch-Based Interfaces, Jared Bott Jan 2016

The Woz Recognizer: A Tool For Understanding User Perceptions Of Sketch-Based Interfaces, Jared Bott

Electronic Theses and Dissertations

Sketch recognition has the potential to be an important input method for computers in the coming years; however, designing and building an accurate and sophisticated sketch recognition system is a time consuming and daunting task. Since sketch recognition is still at a level where mistakes are common, it is important to understand how users perceive and tolerate recognition errors and other user interface elements with these imperfect systems. A problem in performing this type of research is that we cannot easily control aspects of recognition in order to rigorously study the systems. We performed a study examining user perceptions of …

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Building Lax Integrable Variable-Coefficient Generalizations To Integrable Pdes And Exact Solutions To Nonlinear Pdes, Matthew Russo Jan 2016

Building Lax Integrable Variable-Coefficient Generalizations To Integrable Pdes And Exact Solutions To Nonlinear Pdes, Matthew Russo

Electronic Theses and Dissertations

This dissertation is composed of two parts. In Part I a technique based on extended Lax Pairs is first considered to derive variable-coefficient generalizations of various Lax-integrable NLPDE hierarchies recently introduced in the literature. It is demonstrated that the technique yields Lax- or S-integrable nonlinear partial differential equations (PDEs) with both time- and space-dependent coefficients which are thus more general than almost all cases considered earlier via other methods such as the Painleve Test, Bell Polynomials, and various similarity methods. However, this technique, although operationally effective, has the significant disadvantage that, for any integrable system with spatiotemporally varying coefficients, one …

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Broad Bandwidth Optical Frequency Combs From Low Noise, High Repetition Rate Semiconductor Mode-Locked Lasers, Anthony Klee Jan 2016

Broad Bandwidth Optical Frequency Combs From Low Noise, High Repetition Rate Semiconductor Mode-Locked Lasers, Anthony Klee

Electronic Theses and Dissertations

Mode-locked lasers have numerous applications in the areas of communications, spectroscopy, and frequency metrology. Harmonically mode-locked semiconductor lasers with external ring cavities offer a unique combination of benefits in that they can produce high repetition rate pulse trains with low timing jitter, achieve narrow axial mode linewidths, have the potential for entire monolithic integration on-chip, feature high wall-plug efficiency due to direct electrical pumping, and can be engineered to operate in different wavelength bands of interest. However, lasers based on InP/InGaAsP quantum well devices which operate in the important telecom C-band have thus far been relatively limited in bandwidth as …

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Advanced Blue Phase Liquid Crystal Displays, Daming Xu Jan 2016

Advanced Blue Phase Liquid Crystal Displays, Daming Xu

Electronic Theses and Dissertations

Thin-film transistor (TFT) liquid crystal displays (LCDs) have become indispensable in our daily lives. Their widespread applications range from smartphones, laptops, TVs to navigational devices, data projectors and wearable displays. Over past decades, massive efforts have been invested in device development, material characterization and manufacturing technology. As a result, the performance of LCDs, such as viewing angle, contrast ratio, color gamut and resolution, have been improved significantly. Nonetheless, there are still urgent needs for fast response time and low power consumption. Fast response time helps reduce motion image blurs and enable color sequential displays. The latter is particularly attractive since …

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Dynamic Modeling Of Autorotation For Simultaneous Lift And Wind Energy Extraction, Sadaf Mackertich Jan 2016

Dynamic Modeling Of Autorotation For Simultaneous Lift And Wind Energy Extraction, Sadaf Mackertich

Electronic Theses and Dissertations

The goal of this thesis is to develop a multi-body dynamics model of autorotation with the objective of studying its application in energy harvesting. A rotor undergoing autorotation is termed an Autogyro. In the autorotation mode, the rotor is unpowered and its interaction with the wind causes an upward thrust force. The theory of an autorotating rotorcraft was originally studied for achieving safe flight at low speeds and later used for safe descent of helicopters under engine failure. The concept can potentially be used as a means to collect high-altitude wind energy. Autorotation is inherently a dynamic process and requires …

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The Preservice Elementary Teacher Affect Scale For Science: A Validation Study, Otis Wilder Jan 2016

The Preservice Elementary Teacher Affect Scale For Science: A Validation Study, Otis Wilder

Electronic Theses and Dissertations

The current study details the creation of a new scale for measuring preservice teachers' positive affect for science, the Preservice Elementary Teacher Affect Scale for Science (PETAS-S). This new instrument is designed specifically to measure the level of positive affect towards the subject of science in preservice elementary teachers. Confirmatory factor analysis reveals the instrument loads on the single factor, positive affect. Reliability is robust, with Cronbach's alpha of .96. Positive affect has shown to predict future levels of engagement in domain specific academic subjects (Ainley & Ainley, 2011) and is expected to aid preservice teachers in understanding the complex …

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Reading Comprehension Deficits In Children With Adhd: The Mediating Roles Of Working Memory And Orthographic Conversion, Lauren Friedman Jan 2016

Reading Comprehension Deficits In Children With Adhd: The Mediating Roles Of Working Memory And Orthographic Conversion, Lauren Friedman

Electronic Theses and Dissertations

Reading comprehension deficits in children with ADHD are well-established; however, limited information exists concerning the cognitive mechanisms that contribute to these deficits and the extent to which they interact with one another. The current study examines two broad cognitive processes known to be involved in children's reading comprehension abilities—(a) working memory (i.e., central executive processes [CE], phonological short-term memory [PH STM], and visuospatial short-term memory [VS STM]) and (b) orthographic conversion—to elucidate their unique and interactive contribution to ADHD-related reading comprehension deficits. Thirty-one children with ADHD and 30 typically developing (TD) children aged 8 to 12 years (M = 9.64, …

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K-12 Transition Framework For Students With Disabilties, Clydia Delaney Jan 2016

K-12 Transition Framework For Students With Disabilties, Clydia Delaney

Electronic Theses and Dissertations

The problem of practice that this dissertation addressed was the post-secondary transition of students with disabilities, which has garnered national and international attention for decades. This dissertation was completed to inform the educational community regarding the potential for improvement in the post-secondary transition process of students with disabilities. Multiple factors were examined related to helping students with disabilities develop appropriate skills to transition through school into personally successful, post-secondary activities and environments. A pilot study was conducted to inform a potential transition framework. Invitations to participate in an anonymous survey were sent to 741 teachers in the district via email. …

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Towards A Theory Of Autism Spectrum Disorder Program Implementation, Ian Gesundheit Jan 2016

Towards A Theory Of Autism Spectrum Disorder Program Implementation, Ian Gesundheit

Electronic Theses and Dissertations

With the increased prevalence of students qualifying for services within Autism Spectrum Disorder (ASD) programs (Odom, Cox and Brock, 2013), it is imperative that the field comes to better understand how successful programs can be replicated at scale. The implementation of effective instructional programs for students with ASD across school systems on a large scale is a difficult task. School systems have tried to replicate successful programs for diverse learners but have been largely unable to do so. For students with disabilities, who perform poorly compared to their peers without disabilities (Odom et al., 2013), the need to replicate successful …

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Learning In The 21st Century: A Study Addressing Educational Trends And Implications, Rodney Harshbarger Jan 2016

Learning In The 21st Century: A Study Addressing Educational Trends And Implications, Rodney Harshbarger

Electronic Theses and Dissertations

The 21st century workforce is very different from the workforce of our predecessors. With the rise in automation and technology there are new demands that are being placed on employers to produce goods that are faster, more personalized, and more accessible. In order to meet these demands, this generation of employees must have a skillset that complements these demands. This skillset includes communication, collaboration, critical thinking, and creativity (4C) skills. The problem of practice addressed in this dissertation is the lack of 4C skills among students currently in the K-12 education system, and the lack of opportunities students have to …

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Fostering Paths Of Enrollment From An Urban High School To A Large, Public University, Colin Wyenberg Jan 2016

Fostering Paths Of Enrollment From An Urban High School To A Large, Public University, Colin Wyenberg

Electronic Theses and Dissertations

This qualitative study sought to address the problem of lower enrollment of students from Jones High School in Orlando, Florida than is desired by the University of Central Florida (UCF). The university has new developments in the community near Jones High School and this dissertation in practice seeks to develop recruitment practices to increase enrollment of this population. Alumni from Jones High School who currently attend UCF were selected for a qualitative study including a survey and interview to examine the phenomenological experiences regarding their decision to enroll and the path of enrollment they selected. Multiple paths of enrollment exist …

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The Impact Of Various Characteristics Of Prekindergarten Services For Students With Disabilities On Later School Performance, Tanya Shores Jan 2016

The Impact Of Various Characteristics Of Prekindergarten Services For Students With Disabilities On Later School Performance, Tanya Shores

Electronic Theses and Dissertations

This study addressed the problem of limited data for determining the effectiveness of prekindergarten programs for students with disabilities. The purpose of this study was to examine the relationship between participation in ESE services during prekindergarten and long term outcomes for students who received these services. Outcome measures included third grade academic performance and needs for exceptional student education (ESE) services. Regression analysis and correlational analysis were conducted for each of two research questions as appropriate. The findings of this research indicated inconsistent statistically significant relationships between the characteristics of ESE services students with disabilities received during prekindergarten and the …

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A Comparison Of The Academic Achievement Of English Learners And Non-English Learners In Digital And Non-Digital Learning Environments, Enrique Vela Jan 2016

A Comparison Of The Academic Achievement Of English Learners And Non-English Learners In Digital And Non-Digital Learning Environments, Enrique Vela

Electronic Theses and Dissertations

The purpose of this study was to identify the extent to which learning in a digital school environment impacts the reading and mathematics achievement of English learners (ELs) in elementary and secondary school settings. In addition, this study intended to determine the extent, if any, that learning in a digital school environment narrows the achievement gap in reading and mathematics between ELs and their non-EL counterparts in elementary and secondary schools. Based on data collected from the first year of a 1:1 digital pilot implementation in a large urban school district in Florida, the results of this study identified grade …

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Gesture Assessment Of Teachers In An Immersive Rehearsal Environment, Roghayeh Barmaki Jan 2016

Gesture Assessment Of Teachers In An Immersive Rehearsal Environment, Roghayeh Barmaki

Electronic Theses and Dissertations

Interactive training environments typically include feedback mechanisms designed to help trainees improve their performance through either guided- or self-reflection. When the training system deals with human-to-human communications, as one would find in a teacher, counselor, enterprise culture or cross-cultural trainer, such feedback needs to focus on all aspects of human communication. This means that, in addition to verbal communication, nonverbal messages must be captured and analyzed for semantic meaning. The goal of this dissertation is to employ machine-learning algorithms that semi-automate and, where supported, automate event tagging in training systems developed to improve human-to-human interaction. The specific context in which …

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High-Performance Composable Transactional Data Structures, Deli Zhang Jan 2016

High-Performance Composable Transactional Data Structures, Deli Zhang

Electronic Theses and Dissertations

Exploiting the parallelism in multiprocessor systems is a major challenge in the post ``power wall'' era. Programming for multicore demands a change in the way we design and use fundamental data structures. Concurrent data structures allow scalable and thread-safe accesses to shared data. They provide operations that appear to take effect atomically when invoked individually. A main obstacle to the practical use of concurrent data structures is their inability to support composable operations, i.e., to execute multiple operations atomically in a transactional manner. The problem stems from the inability of concurrent data structure to ensure atomicity of transactions composed from …

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Investigating The Moderating Effects Of Optisism, Hope, And Gratitude On The Relationship Among Negative Life Events And Psychological Distress And Life Satisfaction, Abdi Gungor Jan 2016

Investigating The Moderating Effects Of Optisism, Hope, And Gratitude On The Relationship Among Negative Life Events And Psychological Distress And Life Satisfaction, Abdi Gungor

Electronic Theses and Dissertations

The literature has documented that negative life events such as divorce, financial issues, or relationship changes lead to various psychological concerns including depression, anxiety, or suicidal behaviors. However, several variables affect how people cope with negative life events. Among those variables, optimism, hope, and gratitude have been emphasized in the literature, and their relationships with several psychological outcomes have been studied. However, little is known about the effects of these variables on negative life events and their relationship to psychological distress and life satisfaction. The purpose of this study was to investigate the relationship between negative life events and psychological …

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Examining Elementary Preservice Teacher Efficacy To Teach Writing In A Title 1 School: A Mixed Method Study Of A School-Based Teacher Education Course Intervention, Norine Blanch Jan 2016

Examining Elementary Preservice Teacher Efficacy To Teach Writing In A Title 1 School: A Mixed Method Study Of A School-Based Teacher Education Course Intervention, Norine Blanch

Electronic Theses and Dissertations

As the demographics of the United States change, barriers persistently thwart efforts to ensure that all students, regardless of ethnicity, academic ability, or family circumstance, have equal opportunities to learn. Diminished retention rates of effective educators in Title 1 schools, elevated rates at which students from low-income families are taught by inexperienced or unqualified teachers and insufficient preparation of preservice teachers (PSTs) to teach in Title 1 schools are three such barriers. Policy reform organizations interested in improving the effectiveness of teacher education programs nationwide suggest forging strong clinical partnerships between universities and schools by relocating coursework to school-based settings …

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The Role Of Virtual Avatars In Supporting Middle School Students From Culturally And Linguistically Diverse Backgrounds On Science In After School Programs, Benjamin Gallegos Jan 2016

The Role Of Virtual Avatars In Supporting Middle School Students From Culturally And Linguistically Diverse Backgrounds On Science In After School Programs, Benjamin Gallegos

Electronic Theses and Dissertations

Students who receive additional educational supports in afterschool programs were the focus of the investigation. This study was conducted to measure what effects a TeachLivE avatar, a mixed-reality virtual environment, used in combination with a video game, had on the activation of prior knowledge in science for students in rural middle school. The delivery of the biology science lessons on cell structures and processes were delivered using the video game, Cell Command. The TeachLivE adult avatar was customized as a biologist who spoke to students in the treatment group about science concepts prior to playing the science video game. Unexpected …

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Project Ican: A Stem Learning And Persistence Model For Postsecondary Students With Disabilities, Aaron Koch Jan 2016

Project Ican: A Stem Learning And Persistence Model For Postsecondary Students With Disabilities, Aaron Koch

Electronic Theses and Dissertations

Education and work in Science, Technology, Engineering, & Math (STEM) are of utmost importance in a post-modern society. Yet American performance in the STEM disciplines has waned over recent years. In order to recapture a global advantage in STEM, efforts are being made by educators and policy makers to compile and implement instructional supports. Of particular interest to this study are post-secondary students with disabilities (SWDs) who persist and learn in STEM degree paths. This population is an "untapped resource" with limitless potential for contribution to the collective fields of STEM (Leddy, 2010, p. 3; Alston, Hampton, Bell, & Strauss, …

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A Multiple Case Study Examining How Third-Grade Students Who Struggle In Mathematics Make Sense Of Fraction Concepts, Rebecca Gault Jan 2016

A Multiple Case Study Examining How Third-Grade Students Who Struggle In Mathematics Make Sense Of Fraction Concepts, Rebecca Gault

Electronic Theses and Dissertations

A qualitative multiple case study was conducted to reveal the sense-making processes third-grade students who struggle in mathematics used to build an understanding of fraction concepts. Purposive sampling identified three participants who were struggling in a local school's third grade mathematics classes. This research describes how these participants made sense of fraction concepts through their strengths and struggles while engaged in 15 small-group intervention sessions. Vygotsky's (1934/1986/2012) theory that children's optimal learning is supported by teacher-student interactions was used as an interpretive framework. Tasks were developed over the course of the intervention sessions with consideration of a model developed by …

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Impact Of Gamma-Irradiation On The Characteristics Of Iii-N/Gan Based High Electron Mobility Transistors, Anupama Yadav Jan 2016

Impact Of Gamma-Irradiation On The Characteristics Of Iii-N/Gan Based High Electron Mobility Transistors, Anupama Yadav

Electronic Theses and Dissertations

In this study, the fundamental properties of AlGaN/GaN based High Electron Mobility Transistors (HEMTs) have been investigated in order to optimize their performance in radiation harsh environment. AlGaN/GaN HEMTs were irradiated with 60Co gamma-rays to doses up to 1000 Gy, and the effects of irradiation on the devices' transport and optical properties were analyzed. Understanding the radiation affects in HEMTs devices, on carrier transport, recombination rates and traps creation play a significant role in development and design of radiation resistant semiconductor components for different applications. Electrical testing combined with temperature dependent Electron Beam Induced Current (EBIC) that we used in …

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Tryopenjml - A Verily Based Web Application For Learning About The Java Modeling Language, Tushar Deshpande Jan 2016

Tryopenjml - A Verily Based Web Application For Learning About The Java Modeling Language, Tushar Deshpande

Electronic Theses and Dissertations

This thesis has a two-fold purpose. On the one hand, the web applications are an important part of life. On a day to day basis, from managing our heath care choices to banking, to connecting to a friend, almost everything is done through a web application. Development of these applications is also a very trend-driven domain. Numerous web frameworks are available today, but almost none has been created taking reliability into consideration. With the combination of application construction recipes and static analysis, the Verily framework was created to build more reliable web applications. On the other hand, the goal of …

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