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The Dielectric Constant of Galvinoxyl

Description: The molecules in many substances are know to undergo at characteristic temperatures a change in their rotational freedom in the solid state, signifying either a change in structure of the material of the onset of limited rotation of the molecule about some symmetry axis. The purpose of this research was to determine from dielectric constant measurements over the 100°K-420°K temperature range whether or not the organic free radical galvinoxyl and its diamagnetic parent molecule, dihydroxydipheny… more
Date: May 1968
Creator: Mizell, Michael E.
Item Type: Refine your search to only Thesis or Dissertation
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Microwave Cavity Method for Measuring Plasma Properties

Description: This discussion is concerned primarily with communications blackout during spacecraft entry into a planetary atmosphere. The gas in the shock layer, between shock wave and vehicle surface, ionizes from the intense heating which takes place in the bow shock wave and a viscous region of high gas enthalpy. This ionization may persist throughout the subsequent flow over the vehicle and into the wake, thus completely engulfing the vehicle and its communications elements. The problem will be to simul… more
Date: August 1969
Creator: Freeman, Ronald H.
Item Type: Refine your search to only Thesis or Dissertation
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Electrical Conductivity in Thin Films

Description: This thesis deals with electrical conductivity in thin films. Classical and quantum size effects in conductivity are discussed including some experimental evidence of quantum size effects. The component conductivity along the applied electric field of a thin film in a transverse magnetic field is developed in a density matrix method.
Date: May 1973
Creator: Meyer, Frederick Otto
Item Type: Refine your search to only Thesis or Dissertation
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A Study of Minority Atomic Ion Recombination in the Helium Afterglow

Description: Electron-ion recombination has been under study for many years, but comparisons between theory and experiment have been very difficult, especially for conditions where the ion under evaluation was a minority in concentration. This study describes a direct measurement of the recombination-rate coefficient for the recombination of minority as well as majority ions in the afterglow.
Date: August 1972
Creator: Wells, William E.
Item Type: Refine your search to only Thesis or Dissertation
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Ultrafast Spectroscopy of Hybrid Ingan/gan Quantum Wells

Description: Group III nitrides are efficient light emitters. The modification of internal optoelectronic properties of these materials due to strain, external or internal electric field are an area of interest. Insertion of metal nanoparticles (MNPs) (Ag, Au etc) inside the V-shaped inverted hexagonal pits (IHP) of InGaN/GaN quantum wells (QWs) offers the potential of improving the light emission efficiencies. We have observed redshift and blueshift due to the Au MNPs and Ag MNPs respectively. This sh… more
Date: August 2012
Creator: Mahat, Meg Bahadur
Item Type: Refine your search to only Thesis or Dissertation
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A Non-equilibrium Approach to Scale Free Networks

Description: Many processes and systems in nature and society can be characterized as large numbers of discrete elements that are (usually non-uniformly) interrelated. These networks were long thought to be random, but in the late 1990s, Barabási and Albert found that an underlying structure did in fact exist in many natural and technological networks that are now referred to as scale free. Since then, researchers have gained a much deeper understanding of this particular form of complexity, largely by comb… more
Date: August 2012
Creator: Hollingshad, Nicholas W.
Item Type: Refine your search to only Thesis or Dissertation
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Theoretical and Experimental Investigations Concerning Microgels of Varied Spherical Geometries

Description: Polymer gels have been studied extensively due to their ability to simulate biological tissues and to swell or collapse reversibly in response to external stimuli. This work presents a variety of studies using poly-N-isopropylacrylamide (PNIPA) hydrogels. The projects have been carried out both in the lab of Dr. Zhibing Hu and in collaboration with others outside of UNT: (1) an analysis of the swelling kinetics of microgel spherical shells prepared using a novel design of microfluidic devices; … more
Date: August 2012
Creator: Wahrmund, Joshua Joseph
Item Type: Refine your search to only Thesis or Dissertation
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Thorium and Uranium M-shell X-ray Production Cross Sections for 0.4 – 4.0 MeV Protons, 0.4 - 6.0 MeV Helium Ions, 4.5 – 11.3 MeV Carbon Ions, and 4.5 – 13.5 MeV Oxygen Ions.

Description: The M-shell x-ray production cross section for thorium and uranium have been determined for protons of energy 0.4 - 4.0 MeV, helium ions of energy 0.4 - 6.0 MeV, carbon ions of energy 4.5 - 11.3 MeV and oxygen ions of energy 4.5 - 13.5 MeV. The total cross sections and the cross sections for individual x-ray peaks in the spectrum, consisting of the following transitions Mz (M4-N2, M5-N3, M4-N3), Ma (M5-N6,7), Mb (M4-N6, M5-O3, M4- O2), and Mg (M4-O3, M5-P3, M3-N4, M3-N5), were compared to the t… more
Date: May 2011
Creator: Phinney, Lucas C.
Item Type: Refine your search to only Thesis or Dissertation
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Ion Beam Synthesis of Carbon Assisted Nanosystems in Silicon Based Substrates

Description: The systematic study of the formation of β-SiC formed by low energy carbon ion (C-)implantation into Si followed by high temperature annealing is presented. The research is performed to explore the optimal annealing conditions. The formation of crystalline β-SiC is clearly observed in the sample annealed at 1100 °C for a period of 1 hr. Quantitative analysis is performed in the formation of β-SiC by the process of implantation of different carbon ion fluences of 1×1017, 2×1017, 5… more
Date: May 2011
Creator: Poudel, Prakash Raj
Item Type: Refine your search to only Thesis or Dissertation
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Enhancements of Mechanical, Thermal Stability, and Tribological Properties by Addition of Functionalized Reduced Graphene Oxide in Epoxy

Description: The effects of octadecylamine-functionalized reduced graphene oxide (FRGO) on the frictional and wear properties of diglycidylether of bisphenol-A (DGEBA) epoxy are studied using a pin-on-disk tribometer. It was observed that the addition of FRGO significantly improves the tribological, mechanical, and thermal properties of epoxy matrix. Graphene oxide (GO) was functionalized with octadecylamine (ODA), and then reduction of oxygen-containing functional groups was carried out using hydrazine mon… more
Date: August 2014
Creator: Shah, Rakesh K.
Item Type: Refine your search to only Thesis or Dissertation
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Analysis of Biological Materials Using a Nuclear Microprobe

Description: The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhanceme… more
Date: December 2014
Creator: Mulware, Stephen Juma
Item Type: Refine your search to only Thesis or Dissertation
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Electrical Conduction Mechanisms in the Disordered Material System P-type Hydrogenated Amorphous Silicon

Description: The electrical and optical properties of boron doped hydrogenated amorphous silicon thin films (a-Si) were investigated to determine the effect of boron and hydrogen incorporation on carrier transport. The a-Si thin films were grown by plasma enhanced chemical vapor deposition (PECVD) at various boron concentrations, hydrogen dilutions, and at differing growth temperatures. The temperature dependent conductivity generally follows the hopping conduction model. Above a critical temperature, the d… more
Date: December 2014
Creator: Shrestha, Kiran (Engineer)
Item Type: Refine your search to only Thesis or Dissertation
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Temporal Complexity and Stochastic Central Limit Theorem

Description: Complex processes whose evolution in time rests on the occurrence of a large and random number of intermittent events are the systems under study. The mean time distance between two consecutive events is infinite, thereby violating the ergodic condition and activating at the same time a stochastic central limit theorem that explains why the Mittag-Leffler function is a universal property of nature. The time evolution of these complex systems is properly generated by means of fractional differen… more
Date: August 2014
Creator: Pramukkul, Pensri
Item Type: Refine your search to only Thesis or Dissertation
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Studies of Charged Particle Dynamics for Antihydrogen Synthesis

Description: Synthesis and capture of antihydrogen in controlled laboratory conditions will enable precise studies of neutral antimatter. The work presented deals with some of the physics pertinent to manipulating charged antiparticles in order to create neutral antimatter, and may be applicable to other scenarios of plasma confinement and charged particle interaction. The topics covered include the electrostatic confinement of a reflecting ion beam and the transverse confinement of an ion beam in a purely … more
Date: December 2014
Creator: Correa, Jose Ricardo
Item Type: Refine your search to only Thesis or Dissertation
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Sputtering of Bi and Preferential Sputtering of an Inhomogeneous Alloy

Description: Angular distributions and total yields of atoms sputtered from bismuth targets by normally incident 10 keV -50 keV Ne+ and Ar+ ions have been measured both experimentally and by computer simulation. Polycrystalline Bi targets were used for experimental measurements. The sputtered atoms were collected on high purity aluminum foils under ultra-high vacuum conditions, and were subsequently analyzed using Rutherford backscattering spectroscopy. The Monte-Carlo based SRIM code was employed to simula… more
Date: December 2014
Creator: Deoli, Naresh T.
Item Type: Refine your search to only Thesis or Dissertation
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Microwave Line Widths of the Asymmetric Top Formic Acid Molecule

Description: This work consisted of an experimental investigation of the formic acid (HCOOH) molecule's rotational spectrum. Measurements of line widths were obtained for J = 5, 12, 13, 19, and 20 for a pressure range from 1 to 10 microns. A linear behavior between Av and p was observed as predicted by theory. The line width parameter Avp was observed to depend on the quantum number J. Hard sphere collision diameters b1 were calculated using the obtained AvP values. These deduced hard sphere values were fo… more
Date: August 1974
Creator: Maynard, Wayne R.
Item Type: Refine your search to only Thesis or Dissertation
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Effects of Discharge Tube Geometry on Plasma Ion Oscillations

Description: This study considers the effect, on plasma ion oscillations, of various lengths of discharge tubes as well as various cross sections of discharge tubes. Four different gases were used in generating the plasma. Gas pressure and discharge voltage and current were varied to obtain a large number of signals. A historical survey is given to familiarize the reader with the field. The experimental equipment and procedure used in obtaining data is given. An analysis of the data obtained is presented al… more
Date: May 1975
Creator: Simmons, David Warren
Item Type: Refine your search to only Thesis or Dissertation
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Relaxation Time Measurements for Collision Processes in the Surface Layers of Conductors and Semiconductors Near 10 Ghz

Description: This thesis represents one phase of a joint effort of research on the properties of liquids and solids. This work is concerned primarily with the microwave properties of solids. In this investigation the properties exhibited by conductor and semiconductor materials when they are subjected to electromagnetic radiation of microwave frequency are studied. The method utilized in this experiment is the perturbation of a resonant cavity produced by introduction of a cylindrically shaped sample into i… more
Date: December 1973
Creator: Childress, Larry Wayne
Item Type: Refine your search to only Thesis or Dissertation
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Studying Interactions of Gas Molecules with Nanomaterials Loaded in a Microwave Resonant Cavity

Description: A resonant cavity operating in TE011 mode was used to study the adsorption response of single walled carbon nanotubes (SWCNTs) and other nanomaterials for different types of gas molecules. The range of the frequency signal as a probe was chosen as geometry dependent range between 9.1 -9.8 GHz. A highly specific range can be studied for further experiments dependent on the type of molecule being investigated. It was found that for different pressures of gases and for different types of nanomater… more
Date: August 2007
Creator: Anand, Aman
Item Type: Refine your search to only Thesis or Dissertation
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Polymer Gels: Kinetics, Dynamics Studies and Their Applications as Biomaterials

Description: The polymer gels especially hydrogels have a very special structure and useful features such as unusual volume phase transition, compatibility with biological systems, and sensitivity to environmental stimuli (temperature, pH value, electric field, light and more), which lead to many potential applications in physical and biochemical fields. This research includes: (1) the theoretical and experimental studies of polymer gels on swelling kinetics, spinodal decomposition, and solution convection … more
Date: December 2003
Creator: Wang, Changjie
Item Type: Refine your search to only Thesis or Dissertation
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Novel Semi-Conductor Material Systems: Molecular Beam Epitaxial Growth and Characterization

Description: Semi-conductor industry relies heavily on silicon (Si). However, Si is not a direct-band gap semi-conductor. Consequently, Si does not possess great versatility for multi-functional applications in comparison with the direct band-gap III-V semi-conductors such as GaAs. To bridge this gap, what is ideally required is a semi-conductor material system that is based on silicon, but has significantly greater versatility. While sparsely studied, the semi-conducting silicides material systems offer gr… more
Date: December 2013
Creator: Elmarhoumi, Nader M.
Item Type: Refine your search to only Thesis or Dissertation
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Mechanism and the Effect of Microwave-Carbon Nanotube Interaction

Description: A series of experimental results about unusual heating of carbon nanotubes by microwaves is analyzed in this dissertation. Two of vibration types, cantilever type (one end is fixed and the other one end is free), the second type is both ends are fixed, have been studied by other people. A third type of forced vibration of carbon nanotubes under an alternating electromagnetic field is examined in this paper. Heating of carbon nanotubes (CNTs) by microwaves is described in terms of nonlinear dyna… more
Date: December 2005
Creator: Ye, Zhou
Item Type: Refine your search to only Thesis or Dissertation
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