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Control of Laser Plasma Based Accelerators up to 1 GeV

Description: This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and … more
Date: December 3, 2007
Creator: Nakamura, Kei
Partner: UNT Libraries Government Documents Department
open access

Alpha-Decay Studies in the Heavy Element Region

Description: Thesis describing a research conducted to extend observations on nuclear energy levels and how they effect the nucleus itself, and an investigation on the gamma rays associated for the even-even isotopes and to obtain additional data for the oddmass neclei in the hope that more regularities will become apparent for that class of nuclides.
Date: July 3, 1956
Creator: Hummel, John Philip
Partner: UNT Libraries Government Documents Department
open access

Cellulose and cellobiose: adventures of a wandering organic chemist in theoretical chemistry

Description: The energies arising from the rotation of free hydroxyl groups in the central glucose residue of a cellulose crystalline assembly, calculated using RHF, DFT, and FMO2/MP2 methods, will be presented. In addition, interactions of this central glucose residue with some of the surrounding residues (selected on the basis of the interaction strengths) are analyzed. The mechanism of acid-catalyzed hydrolysis of cellobiose, which is the repeating unit of cellulose. Energies corresponding to the differe… more
Date: April 3, 2012
Creator: Baluyut, John
Partner: UNT Libraries Government Documents Department
open access

Increasing the efficiency of organic solar cells by photonic and electrostatic-field enhancements

Description: Organic photovoltaic (OPV) technology is an attractive solar-electric conversion paradigm due to the promise of low cost roll-to-roll production and amenability to flexible substrates. Power conversion efficiency (PCE) exceeding 7% has recently been achieved. OPV cells suffer from low charge carrier mobilities of polymers, leading to recombination losses, higher series resistances and lower fill-factors. Thus, it is imperative to develop fabrication methodologies that can enable efficient optic… more
Date: November 3, 2012
Creator: Nalwa, Kanwar
Partner: UNT Libraries Government Documents Department
open access

A measurement of the 2 neutrino double beta decay rate of Te-130 in the CUORICINO experiment

Description: CUORICINO was a cryogenic bolometer experiment designed to search for neutrinoless double beta decay and other rare processes, including double beta decay with two neutrinos (2{nu}{beta}{beta}). The experiment was located at Laboratori Nazionali del Gran Sasso and ran for a period of about 5 years, from 2003 to 2008. The detector consisted of an array of 62 TeO{sub 2} crystals arranged in a tower and operated at a temperature of #24;10 mK. Events depositing energy in the detectors, such as radi… more
Date: November 3, 2011
Creator: Kogler, Laura
Partner: UNT Libraries Government Documents Department
open access

Two-proton pickup studies with the (6Li,8B) reaction

Description: The (/sup 6/Li,/sup 8/B) reaction has been investigated on targets of /sup 26/Mg, /sup 24/Mg, /sup 16/O, /sup 13/C, /sup 12/C, /sup 11/B, /sup 10/B, and /sup 9/Be at a bombarding energy of 80.0 MeV, and on targets of /sup 16/O, /sup 12/C, /sup 9/Be, /sup 7/Li, and /sup 6/Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this… more
Date: December 3, 1976
Creator: Weisenmiller, Robert Benjamin
Partner: UNT Libraries Government Documents Department
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Perfluorodiethoxymethane on nickel and nickel oxide surfaces

Description: The interaction of perfluorodiethoxymethane with a nickel single crystal, Ni(100); a nickel crystal with chemisorbed oxygen, Ni(100)-c(2x2)O; and a nickel crystal with nickel oxide crystallites, NiO(100) is investigated in an ultra high vacuum environment using thermal desorption spectroscopy and high resolution electron energy loss spectroscopy. Nickel, a component of hard disk drives and stainless steel, is used to represent metal surfaces in these {open_quotes}real{close_quotes} systems. Per… more
Date: March 3, 1994
Creator: Jacobson, J.
Partner: UNT Libraries Government Documents Department
open access

Hamiltonian lattice field theory: Computer calculations using variational methods

Description: I develop a variational method for systematic numerical computation of physical quantities -- bound state energies and scattering amplitudes -- in quantum field theory. An infinite-volume, continuum theory is approximated by a theory on a finite spatial lattice, which is amenable to numerical computation. I present an algorithm for computing approximate energy eigenvalues and eigenstates in the lattice theory and for bounding the resulting errors. I also show how to select basis states and choo… more
Date: December 3, 1991
Creator: Zako, R. L.
Partner: UNT Libraries Government Documents Department
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Syntheses and Studies of Acetylenic Polymers

Description: Based on new diiodo aryl compounds a series of novel soluble polymers, poly(2,5-dialkoxy-1,4-phenyleneethynylene)s (PPE polymers) were synthesized using palladium-catalysis. The molecular weights (MW) range from 8,000 to 40,000. Properties such as absorption, fluorescence, and conductivity were studied. A PPE polymer with butoxy side chain exhibits a weak electrical conductivity ({sigma} = 10{sup {minus}3} S/cm) after doping with AsF{sub 5}. Absorption spectra in THF solution at room temperatur… more
Date: March 3, 1994
Creator: Ding, Yiwei
Partner: UNT Libraries Government Documents Department
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Wave propagation in photonic crystals and metamaterials: Surface waves, nonlinearity and chirality

Description: Photonic crystals and metamaterials, both composed of artificial structures, are two interesting areas in electromagnetism and optics. New phenomena in photonic crystals and metamaterials are being discovered, including some not found in natural materials. This thesis presents my research work in the two areas. Photonic crystals are periodically arranged artificial structures, mostly made from dielectric materials, with period on the same order of the wavelength of the working electromagnetic w… more
Date: December 3, 2009
Creator: Wang, Bingnan
Partner: UNT Libraries Government Documents Department
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Absorption and emission properties of photonic crystals and metamaterials

Description: We study the emission and absorption properties of photonic crystals and metamaterials using Comsol Multiphysics and Ansoft HFSS as simulation tools. We calculate the emission properties of metallic designs using drude model and the results illustrate that an appropriate termination of the surface of the metallic structure can significantly increase the absorption and therefore the thermal emissivity. We investigate the spontaneous emission rate modifications that occur for emitters inside two-… more
Date: August 3, 2007
Creator: Peng, Lili
Partner: UNT Libraries Government Documents Department
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Mutiscale Modeling of Segregation in Granular Flows

Description: Modeling and simulation of segregation phenomena in granular flows are investigated. Computational models at different scales ranging from particle level (microscale) to continuum level (macroscale) are employed in order to determine the important microscale physics relevant to macroscale modeling. The capability of a multi-fluid model to capture segregation caused by density difference is demonstrated by simulating grain-chaff biomass flows in a laboratory-scale air column and in a combine har… more
Date: August 3, 2007
Creator: Sun, Jin
Partner: UNT Libraries Government Documents Department
open access

Detecting Molecular Properties by Various Laser-Based Techniques

Description: Four different laser-based techniques were applied to study physical and chemical characteristics of biomolecules and dye molecules. These techniques are liole burning spectroscopy, single molecule spectroscopy, time-resolved coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence microscopy. Results from hole burning and single molecule spectroscopy suggested that two antenna states (C708 & C714) of photosystem I from cyanobacterium Synechocystis PCC 6803 are connected by effect… more
Date: August 3, 2007
Creator: Hsin, Tse-Ming
Partner: UNT Libraries Government Documents Department
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Performance of Planted Herbaceous Species in Longleaf Pine (Pinus palustris Mill.) Plantations: Overstory Effects of Competition and Needlefall

Description: Research to determine the separate effects of above-ground and below-ground competition and needlefall of over-story pines on under-story plant performance. Periodic monitoring of over-story crown closure, soil water content, temperature, and nutrients were conducted. Results indicate competition for light had a more determental effect on performance of herbaceous species in longleaf pine plantations than that resulting from competition for below-ground resources.
Date: July 3, 2001
Creator: Dagley, Christa Marie
Partner: UNT Libraries Government Documents Department
open access

Authenticated group Diffie-Hellman key exchange: theory and practice

Description: Authenticated two-party Diffie-Hellman key exchange allows two principals A and B, communicating over a public network, and each holding a pair of matching public/private keys to agree on a session key. Protocols designed to deal with this problem ensure A (B resp.)that no other principals aside from B (A resp.) can learn any information about this value. These protocols additionally often ensure A and B that their respective partner has actually computed the shared secret value. A natural exte… more
Date: October 3, 2002
Creator: Chevassut, Olivier
Partner: UNT Libraries Government Documents Department
open access

Ultrafast dynamics of electrons at interfaces

Description: Electronic states of a thin layer of material on a surface possess unique physical and chemical properties. Some of these properties arise from the reduced dimensionality of the thin layer with respect to the bulk or the properties of the electric field where two materials of differing dielectric constants meet at an interface. Other properties are related to the nature of the surface chemical bond. Here, the properties of excess electrons in thin layers of Xenon, Krypton, and alkali metals are… more
Date: May 3, 1999
Creator: McNeill, Jason D.
Partner: UNT Libraries Government Documents Department
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Criticisms of Patriarchy in Women's Captivity Narratives: A Close Look at Mary Rowlandson's The Sovereignty and Goodness of God (1862) and Sarah Wakefield's Six Weeks in the Sioux Tepees: A Narrative of Indian Captivity (1862)

Description: Undergraduate thesis exploring criticisms of patriarchy in women's captivity narratives by examining Mary Rowlandson's The Sovereignty and Goodness of God (1862) and Sarah Wakefield's Six Weeks in the Sioux Tepees: A Narrative of Indian Captivity (1862). Both used their socially acceptable roles in order to assert their own ideas regarding the patriarchy. The author concludes that both narratives therefore assert that patriarchal societies did not necessarily produce justice for English or Amer… more
Date: May 3, 2013
Creator: Hansard, Chelsea
Partner: UNT Honors College
open access

Concurrences in the U. S. Supreme Court

Description: Thesis written by a student in the UNT Honors College discussing different types of opinions within the United States Supreme Court, with an emphasis on the history and practice of concurrences.
Date: April 3, 2000
Creator: Watson, Takiesha
Partner: UNT Honors College
open access

My Spent Life's Breath: A Psychoanalytic Study of Don Carlo Gesualdo

Description: Undergraduate thesis psychoanalyzing the composer Don Carlo Gesualdo. It focuses on the relationship between the composer and mastery of the musical task. The author examines the life and work of Don Carlo Gesualdo, Prince of Venosa, who was commonly referred to as both musician and murderer.
Date: December 3, 2012
Creator: Coronado, Sam
Partner: UNT Honors College
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