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  Partner: UNT Libraries
 Degree Discipline: Physics
The Optimum Design of a Broad-band Helix for Use in Electron Spin Resonance

The Optimum Design of a Broad-band Helix for Use in Electron Spin Resonance

Date: June 1967
Creator: Garlow, John R.
Description: This thesis examines optimum designs for broad-band helix to be used in electron spin resonance.
Contributing Partner: UNT Libraries
Electrical Conductivity in Thin Films

Electrical Conductivity in Thin Films

Date: May 1973
Creator: Meyer, Frederick Otto
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.
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A Non-equilibrium Approach to Scale Free Networks

A Non-equilibrium Approach to Scale Free Networks

Date: August 2012
Creator: Hollingshad, Nicholas W.
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 combining graph theory, statistical physics, and advances in computing technology. This dissertation focuses on out-of-equilibrium dynamic processes as they unfold on these complex networks. Diffusion in networks of non-interacting nodes is shown to be temporally complex, while equilibrium is represented by a stable state with Poissonian fluctuations. Scale free networks achieve equilibrium very quickly compared to regular networks, and the most efficient are those with the lowest inverse power law exponent. Temporally complex diffusion also occurs in networks with interacting nodes under a cooperative decision-making model. At a critical value of the cooperation parameter, the most efficient scale free network achieves consensus almost as quickly as the equivalent all-to-all network. This finding suggests that the ubiquity of scale free networks in nature ...
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Theoretical and Experimental Investigations Concerning Microgels of Varied Spherical Geometries

Theoretical and Experimental Investigations Concerning Microgels of Varied Spherical Geometries

Date: August 2012
Creator: Wahrmund, Joshua Joseph
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; (2) a comparison of the drug-release rates between nanoparticle structures having either core or core-with-shell (core-shell) designs; (3) an investigation into the thermodynamics of swelling for microgels of exceedingly small size.
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Ultrafast Spectroscopy of Hybrid Ingan/gan Quantum Wells

Ultrafast Spectroscopy of Hybrid Ingan/gan Quantum Wells

Date: August 2012
Creator: Mahat, Meg Bahadur
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 shift could be due to the electric field created by the MNPs through electrostatic image charge. We have studied the ultrafast carrier dynamics of carriers in hybrid InGaN/GaN QWs. The change in quantum confinement stark effect due to MNPs plays an important role for slow and fast carrier dynamics. We have also observed the image charge effect on the ultrafast differential transmission measurement due to the MNPs. We have studied the non-linear absorption spectroscopy of these materials. The QWs behave as a discharging of a nanocapacitor for the screening of the piezoelectric field due to the photo-excited carriers. We have separated out screening and excitonic bleaching components from the main differential absorption spectra of InGaN/GaN QWs.
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Transport Phenomena in Indium Arsenide at Low Temperatures

Transport Phenomena in Indium Arsenide at Low Temperatures

Date: August 1968
Creator: Luke, Paul Jacob
Description: This thesis looks at the transport phenomena in indium arsenide at low temperatures.
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Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Date: January 1969
Creator: Adams, Charles N.
Description: This thesis is a study of the solutions of the equations of radiative transfer by an invariant imbedding approach.
Contributing Partner: UNT Libraries
Monte Carlo Calculations of Reflected Intensities for Real Spherical Atmospheres

Monte Carlo Calculations of Reflected Intensities for Real Spherical Atmospheres

Date: January 1969
Creator: Montgomery, John A.
Description: To calculate the emergent radiation field, a realistic atmospheric model and algorithm must be developed. The radiation field may be characterized by the emergent intensities of scattered light. This is possible only if the algorithm determines these intensities as dependent upon atmospheric and angular parameters.
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Boundary Scattering of Electrons in Thin Cadmium Single Crystals

Boundary Scattering of Electrons in Thin Cadmium Single Crystals

Date: August 1968
Creator: Fortmayer, Gary William
Description: In the present investigation, zinc was plated onto a cadmium crystal to determine the effect on the scattering parameter.
Contributing Partner: UNT Libraries
Size Effect in the Electrical Conductivity of Bismuth

Size Effect in the Electrical Conductivity of Bismuth

Date: August 1967
Creator: Vaughn, Bobby J.
Description: If a physical dimension of a metallic specimen is comparable with, or smaller than, the mean free path of the conduction electrons, then the observed electrical conductivity will be less than that of a conventional bulk sample. This phenomenon is called a size effect, and is the result of electron scattering from the specimen surfaces. In the present investigation, measurements were made on electropolished monocrystalline specimens ranging from matchbox geometry to thick-film geometry in order to obtain further information on the size effect in bismuth at liquid helium temperatures.
Contributing Partner: UNT Libraries