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Placing High-Redshift Quasars in Perspective: Unifying Distant Quasars with Their Lower Redshift Counterparts through Near-Infrared Spectroscopy

Description: I present spectroscopic measurements for 260 sources from the Gemini Near Infrared Spectrograph–Distant Quasar Survey (GNIRS-DQS). Being the largest uniform, homogeneous survey of its kind, it represents a flux-limited sample of Sloan Digital Sky Survey (SDSS) quasars at 1.5 < z < 3.5. A combination of the GNIRS and SDSS spectra covers principal quasar diagnostic features, chiefly the C IV λ1549, Mg II λλ2798, 2803, Hβ λ4861, and [O III] λλ4959, 5007 emission lines, in each source. The spectral… more
Date: May 2023
Creator: Matthews, Brandon M.
Item Type: Refine your search to only Thesis or Dissertation

Twisted Moire Photonic Crystals: Their Nano-Fabrications, Optical Properties, and Applications in Light Extraction

Description: In this dissertation, I report the results of my research on twisted moiré photonic crystals which can be formed through multi-beam holographic interference without a physical rotation and later fabricated by electron-beam lithography. Their optical properties, such as photonic bandgaps, multiple resonance modes, and quality factor are presented. Randomized moire photonic crystals in lattice are also studied. The applications of moire photonic crystals in improving light extraction efficiency … more
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Date: May 2023
Creator: Alnasser, Khadijah Saleh T.
Item Type: Refine your search to only Thesis or Dissertation
open access

Classical Simulations of the Drift of Magnetobound States of Positronium

Description: The production and control of antihydrogen at very low temperatures provided a key tool to test the validity for the antimaterial of the fundamental principles of the interactions of nature such as the weak principle of equivalence (WEP), and CPT symmetry (Charge, Parity, and Time reversal). The work presented in this dissertation studies the collisions of electrons and positrons in strong magnetic fields that generate magnetobound positronium (positron-electron system temporarily bound due to … more
Date: August 2021
Creator: Aguirre Farro, Franz
Item Type: Refine your search to only Thesis or Dissertation

Low-Energy Electron Irradiation of 2D Graphene and Stability Investigations of 2D MoS2

Description: In this work, we demonstrate the mechanism for etching exfoliated graphene on SiO2 and other technological important substrates (Si, SiC and ITO), using low-energy electron sources. Our mechanism is based on helium ion sputtering and vacancy formation. Helium ions instead of incident electrons cause the defects that oxygen reacts with and etches graphene. We found that etching does not occur on low-resistivity Si and ITO. Etching occurs on higher resistivity Si and SiC, although much less than … more
Date: August 2021
Creator: Femi Oyetoro, John Dideoluwa
Item Type: Refine your search to only Thesis or Dissertation
open access

Renewal and Memory Approaches to Study Biological and Physiological Processes

Description: In nature we find many instances of complex behavior for example the dynamics of stock markets, power grids, internet networks, highway traffic, social networks, heartbeat dynamics, neural dynamics, dynamics of living organisms, etc. The study of these complex systems involves the use of tools of non-linear dynamics and non-equilibrium statistical physics. This dissertation is devoted to understanding two different sources of complex behavior – non-poissonian renewal events also called crucial… more
Date: May 2019
Creator: Tuladhar, Rohisha
Item Type: Refine your search to only Thesis or Dissertation
open access

Examination of Magnetic Plasma Expulsion

Description: Magnetic plasma expulsion uses a magnetic field distortion to redirect incident charged particles around a certain area for the purposes of shielding. Computational studies are carried out and for certain values of magnetic field, magnetic plasma expulsion is found to effectively shield a sizable area. There are however many plasma behaviors and interactions that must be considered. Applications to a new cryogenic antimatter trap design are discussed.
Date: May 2018
Creator: Phillips, Ryan Edward
Item Type: Refine your search to only Thesis or Dissertation
open access

Artificially Structured Boundary for Control and Confinement of Beams and Plasmas

Description: An artificially structured boundary (ASB) produces a short-range, static electromagnetic field that can reflect charged particles. In the work presented, an ASB is considered to consist of a spatially periodic arrangement of electrostatically plugged magnetic cusps. When used to create an enclosed volume, an ASB may confine a non-neutral plasma that is effectively free of applied electromagnetic fields, provided the spatial period of the ASB-applied field is much smaller than any one dimension … more
Date: May 2018
Creator: Hedlof, Ryan
Item Type: Refine your search to only Thesis or Dissertation
open access

A Search for Periodic and Quasi-Periodic Patterns in Select Proxy Data with a Goal to Understanding Temperature Variation

Description: In this work over 200 temperature proxy data sets have been analyzed to determine if periodic and or quasi-periodic patterns exist in the data sets. References to the journal articles where data are recorded are provided. Chapter 1 serves an introduction to the problem of temperature determination in providing information on how various proxy data sources are derived. Examples are given of the techniques followed in producing proxy data that predict temperature for each method used. In chapte… more
Date: May 2016
Creator: Otto, James (James Robert)
Item Type: Refine your search to only Thesis or Dissertation

Fabrication of Nano-Channel Templates and a Study of the Electrical and Magnetic Properties of Nanowires Grown in Template Pores

Description: This thesis is a study of the structural, electrical and magnetic properties of indium antimonide (InSb) nanowires (NWs), that were synthesized by a template-assisted ordered growth technique via electrochemical deposition. InSb was chosen for this study because of its intrinsic properties that make it a material of choice for applications in high channel mobility, infrared (IR) sensing, thermoelectrics, and magnetoresistive sensing martials. This work has four main components: (i) Growth in co… more
Date: May 2020
Creator: Singh, Abhay Pratap
Item Type: Refine your search to only Thesis or Dissertation

Manipulation of Light-Matter Interactions in Molybdenum Disulfide (MoS2) Monolayer through Dressed Phonons (DP) and Plasmons

Description: The performance of electrical and optical devices based on two-dimensional semiconductors (2D) such as molybdenum disulfide is critically influenced due to very poor light absorption in the atomically thin layers. In this study, the phonon mediated optical absorption and emission properties in single atomic layers of MoS2 have been investigated. The electronic transitions in MoS2 due to near-field optical interaction and the influence of interface phonons due to the dielectric substrate GaN on … more
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Date: December 2019
Creator: Poudel, Yuba R
Item Type: Refine your search to only Thesis or Dissertation
open access

A Collisional Mechanism in the Ion-Solid Interaction Which Enhances Scattering Yields Near 180⁰

Description: In the course of experiments using uniaxial double alignment channeling to investigate radiation damage in single crystals, an anomalously large ion-scattering yield from the near surface of disordered or simulated disordered solid targets was observed. The chronology of the discovery of this new ion-solid effect and its explanation are presented along with experiments detailing the dependence of the new effect upon ion type and energy, as well as target atomic number and density. Targets inclu… more
Date: December 1980
Creator: Holland, Orin Wayne
Item Type: Refine your search to only Thesis or Dissertation
open access

Formation of Supersaturated Alloys by Ion Implantation and Pulsed-Laser Annealing

Description: Supersaturated substitutional alloys formed by ion implantation and rapid liquid-phase epitaxial regrowth induced by pulsed-laser annealing have been studied using Rutherford-backscattering and ion-channeling analysis. A series of impurities (As, Sb, Bi, Ga, In, Fe, Sn, Cu) have been implanted into single-crystal (001) orientation silicon at doses ranging from 1 x 10^15/cm2 to 1 x 10^17/cm2. The samples were subsequently annealed with a Ω-switched ruby laser (energy density ~1.5 J/cm2, pulse du… more
Date: August 1979
Creator: Wilson, Syd Robert
Item Type: Refine your search to only Thesis or Dissertation
open access

Phase Transition Studies in Polar and Nonpolar Liquids at Microwave Frequencies

Description: A resonant microwave cavity technique was employed to study the dielectric behavior of some polar and non-polar liquids near the phase transition temperatures at microwave frequencies of 7.2, 9.2 and 10.1 GHz. The Slater perturbation equations for a resonant microwave cavity are briefly discussed to show that the above technique can be used to determine both the real and imaginary parts of dielectric response. Abrupt changes in dielectric response were observed near the phase transition tempera… more
Date: August 1980
Creator: Dahiya, Jai N. (Jai Narain)
Item Type: Refine your search to only Thesis or Dissertation
open access

Electromagnetically Modulated Sonic Structures

Description: Phononic crystals are structures composed of periodically arranged scatterers in a background medium that affect the transmission of elastic waves. They have garnered much interest in recent years for their macro-scale properties that can be modulated by the micro-scale components. The elastic properties of the composite materials, the contrast in the elastic properties of the composite materials, and the material arrangement all directly affect how an elastic wave will behave as it propagates … more
Date: May 2014
Creator: Walker, Ezekiel Lee
Item Type: Refine your search to only Thesis or Dissertation
open access

A Positive Ion Source

Description: This paper describes the construction of a positive ion source of the electrodeless discharge type and may be divided into two main topis; (1) the radio frequency oscillator and power amplifier and associated power supply and (2) the ionization chamber.
Date: 1948
Creator: Hannah, Kenneth W.
Item Type: Refine your search to only Thesis or Dissertation
open access

Dipole Moments of Diphenyl Compounds with Conjugated Double Bonds

Description: This thesis is a continuation of a study of molecular moments begun by Joseph T. Fielder. In his paper he discussed the theory and the equipment necessary for such a study. It is the purpose of this paper to set forth modifications of his equipment, to present data obtained with this modified equipment, and to interpret this data.
Date: 1950
Creator: Spalding, Dan W.
Item Type: Refine your search to only Thesis or Dissertation
open access

The Interactions of Plasma with Low-k Dielectrics: Fundamental Damage and Protection Mechanisms

Description: Nanoporous low-k dielectrics are used for integrated circuit interconnects to reduce the propagation delays, and cross talk noise between metal wires as an alternative material for SiO2. These materials, typically organosilicate glass (OSG) films, are exposed to oxygen plasmas during photoresist stripping and related processes which substantially damage the film by abstracting carbon, incorporating O and OH, eventually leading to significantly increased k values. Systematic studies have been … more
Date: August 2011
Creator: Behera, Swayambhu Prasad
Item Type: Refine your search to only Thesis or Dissertation
open access

Highly Efficient Single Frequency Blue Laser Generation by Second Harmonic Generation of Infrared Lasers Using Quasi Phase Matching in Periodically Poled Ferroelectric Crystals

Description: Performance and reliability of solid state laser diodes in the IR region exceeds those in the visible and UV part of the light spectrum. Single frequency visible and UV laser diodes with higher than 500 mW power are not available commercially. However we successfully stabilized a multi-longitudinal mode IR laser to 860 mW single frequency. This means high efficiency harmonic generation using this laser can produce visible and UV laser light not available otherwise. In this study we examined… more
Date: August 2014
Creator: Khademian, Ali
Item Type: Refine your search to only Thesis or Dissertation
open access

Interaction of Plasmons and Excitons for Low-Dimension Semiconductors

Description: The effects of surface plasmon for InGaN/GaN multi-quantum wells and ZnO nanoparticles optical linear and nonlinear emission efficiency had been experimentally studied. Due to the critical design for InGaN MQWs with inverted hexagonal pits based on GaN, both contribution of surface plasmon effect and image charge effect at resonant and off resonant frequencies were experimentally and theoretically investigated. With off- resonant condition, the InGaN MQWs emission significantly enhanced by meta… more
Date: December 2014
Creator: Lin, Jie (physicist)
Item Type: Refine your search to only Thesis or Dissertation
open access

Oligonucleotide guanosine conjugated to gallium nitride nano-structures for photonics.

Description: In this work, I studied the hybrid system based on self-assembled guanosine crystal (SAGC) conjugated to wide-bandgap semiconductor gallium nitride (GaN). Guanosine is one of the four bases of DNA and has the lowest oxidation energy, which favors carrier transport. It also has large dipole moment. Guanosine molecules self-assemble to ribbon-like structure in confined space. GaN surface can have positive or negative polarity depending on whether the surface is Ga- or N-terminated. I studied… more
Date: August 2008
Creator: Li, Jianyou
Item Type: Refine your search to only Thesis or Dissertation
open access

The Nonadditive Generalization of Klimontovich's S-Theorem for Open Systems and Boltzmann's Orthodes

Description: We show that the nonadditive open systems can be studied in a consistent manner by using a generalized version of S-theorem. This new generalized S-theorem can further be considered as an indication of self-organization in nonadditive open systems as prescribed by Haken. The nonadditive S-theorem is then illustrated by using the modified Van der Pol oscillator. Finally, Tsallis entropy as an equilibrium entropy is studied by using Boltzmann's method of orthodes. This part of dissertation shows … more
Date: August 2008
Creator: Bagci, Gokhan Baris
Item Type: Refine your search to only Thesis or Dissertation
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