The Stopping Power of Amorphous and Channelled Silicon at All Energies as Computed with the Binary Encounter Approximation (open access)

The Stopping Power of Amorphous and Channelled Silicon at All Energies as Computed with the Binary Encounter Approximation

This thesis utilizes the binary encounter approximation to calculate the stopping power of protons penetrating silicon. The main goal of the research was to make predictions of the stopping power of silicon for low-energy and medium-energy channelled protons, in the hope that this will motivate experiments to test the theory developed below. In attaining this goal, different stopping power theories were compared and the binary encounter approach was applied to random (non-channelled) and high-energy channelled protons in silicon, and these results were compared with experimental data.
Date: December 1994
Creator: Bickel, David, 1970-
System: The UNT Digital Library
A Technique for Increasing the Optical Strength of Single-Crystal NaCl and KCl Through Temperature Cycling (open access)

A Technique for Increasing the Optical Strength of Single-Crystal NaCl and KCl Through Temperature Cycling

This thesis relates a technique for increasing the optical strength of NaCl and KCl single-crystal samples. The 1.06-μm pulsed laser damage thresholds were increased by factors as large as 4.6 for a bulk NaCl single-crystal sample. The bulk laser damage breakdown threshold (LDBT) of the crystal was measured prior to and after heat treatment at 800*C using a Nd:YAG laser operating at 1.06 μm. Bulk and surface LDBTs were also studied on samples annealed at 400° C. These samples showed differences in damage morphology on both cleaved and polished surfaces, and the cleaved surfaces had improved damage thresholds. However, neither the polished surfaces nor the bulk showed improved threshold at the lower annealing temperature.
Date: May 1983
Creator: Franck, Jerome B. (Jerome Bruce)
System: The UNT Digital Library
Dynamic Screening via Intense Laser Radiation and Its Effects on Bulk and Surface Plasma Dispersion Relations (open access)

Dynamic Screening via Intense Laser Radiation and Its Effects on Bulk and Surface Plasma Dispersion Relations

Recent experimentation with excitation of surface plasmons on a gold film in the Kretschmann configuration have shown what appears to be a superconductive effect. Researchers claimed to see the existence of electron pairing during scattering as well as magnetic field repulsion while twisting the polarization of the laser. In an attempt to explain this, they pointed to a combination of electron-electron scattering in external fields as well as dynamic screening via intense laser radiation. This paper expands upon the latter, taking a look at the properties of a dynamic polarization function, its effects on bulk and surface plasmon dispersion relations, and its various consequences.
Date: August 2017
Creator: Lanier, Steven t
System: The UNT Digital Library
Automatic Frequency Control of Microwave Radiation Sources (open access)

Automatic Frequency Control of Microwave Radiation Sources

Resonant cavity controlled klystron frequency stabilization circuits and quartz-crystal oscillator frequency stabilization circuits were investigated for reflex klystrons operating at frequencies in the X-band range. The crystal oscillator circuit employed achieved better than 2 parts in 10 in frequency stability. A test of the functional properties of the frequency standard was made using the Stark effect in molecules.
Date: August 1979
Creator: Payne, Bobby D.
System: The UNT Digital Library
The Classical Limit of Quantum Mechanics (open access)

The Classical Limit of Quantum Mechanics

The Feynman path integral formulation of quantum mechanics is a path integral representation for a propagator or probability amplitude in going between two points in space-time. The wave function is expressed in terms of an integral equation from which the Schrodinger equation can be derived. On taking the limit h — 0, the method of stationary phase can be applied and Newton's second law of motion is obtained. Also, the condition the phase vanishes leads to the Hamilton - Jacobi equation. The secondary objective of this paper is to study ways of relating quantum mechanics and classical mechanics. The Ehrenfest theorem is applied to a particle in an electromagnetic field. Expressions are found which are the hermitian Lorentz force operator, the hermitian torque operator, and the hermitian power operator.
Date: December 1977
Creator: Hefley, Velton Wade
System: The UNT Digital Library
Test of Gauge Invariance: Charged Harmonic Oscillator in an Electromagnetic Field (open access)

Test of Gauge Invariance: Charged Harmonic Oscillator in an Electromagnetic Field

The gauge-invariant formulation of quantum mechanics is compared to the conventional approach for the case of a one-dimensional charged harmonic oscillator in an electromagnetic field in the electric dipole approximation. The probability of finding the oscillator in the ground state or excited states as a function of time is calculated, and the two approaches give different results. On the basis of gauge invariance, the gauge-invariant formulation of quantum mechanics gives the correct probability, while the conventional approach is incorrect for this problem. Therefore, expansion coefficients or a wave function cannot always be interpreted as probability amplitudes. For a physical interpretation as probability amplitudes the expansion coefficients must be gauge invariant.
Date: August 1980
Creator: Wen, Chang-tai
System: The UNT Digital Library
A Continuously Sensitive Cloud Chamber (open access)

A Continuously Sensitive Cloud Chamber

A continuous cloud chamber would be a valuable asset to laboratory work in nuclear and atomic physics. For this reason the construction and investigation of a continuously sensitive diffusion cloud chamber has been undertaken. It is the purpose of this paper to report the design and operating characteristics of such a chamber.
Date: 1951
Creator: Hughes, James E.
System: The UNT Digital Library
Crystalline Polymorphism of Nitrates (open access)

Crystalline Polymorphism of Nitrates

The purpose of this study was to investigate the polymorphism of a group of related compounds. Special emphasis was placed upon the temperature at which transitions occurred and a possible correlation of these temperatures with other properties of the compounds.
Date: 1951
Creator: Shepherd, Jimmie G.
System: The UNT Digital Library
A Deuterium-Deuterium Type Neutron Source (open access)

A Deuterium-Deuterium Type Neutron Source

In view of the advantages of its type, the decision to construct a neutron source of the particle accelerator type was made. The purpose of this thesis is to survey the problems encountered in the construction of the source.
Date: 1951
Creator: Windham, Pat M.
System: The UNT Digital Library
A Two-Dimensional Model Study of Elastic Waves (open access)

A Two-Dimensional Model Study of Elastic Waves

In seismic field operations complex problems often arise which cannot be solved mathematically. In recent years investigators in both the commercial and academic fields have begun to approach the problems of elastic wave propagation by the use of seismic scale models. This thesis discusses the results measured from simulated seismic activity on a scale model built by the researcher.
Date: 1955
Creator: Fulton, Thomas K.
System: The UNT Digital Library
Dipole Moments of Olefenic Diesters (open access)

Dipole Moments of Olefenic Diesters

It is the purpose of this paper to present experimental data for the determination of the dielectric constant and the dipole moments for a series of olefenic diesters of the cis and trans configurations.
Date: 1951
Creator: Shipley, Floyd D.
System: The UNT Digital Library
Absolute Beta Counting Using Thick Sources (open access)

Absolute Beta Counting Using Thick Sources

The problem with which we shall concern ourselves in this paper is the self-scattering and self-absorption of beta particles by the source.
Date: 1950
Creator: Anderson, Miles E., 1926-
System: The UNT Digital Library
A Positive Ion Source (open access)

A Positive Ion Source

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.
System: The UNT Digital Library
The Stereochemistry of Diphenylhexatriene (open access)

The Stereochemistry of Diphenylhexatriene

The problem with which this paper is concerned has as its basis one of the most important properties of the conjugated system of double bonds found in some organic molecules, namely, the ability to exhibit stereoisomerism.
Date: 1948
Creator: Secrest, Everett Leigh
System: The UNT Digital Library
Superconductivity (open access)

Superconductivity

This thesis is a study of the phenomenon of superconductivity.
Date: 1948
Creator: Ward, M. B.
System: The UNT Digital Library
Measurement of Dielectric Constant and Dipole Moment of Liquids (open access)

Measurement of Dielectric Constant and Dipole Moment of Liquids

A study of procedures and techniques of measuring dielectric constant and dipole moment of liquids.
Date: 1948
Creator: Fielder, Joseph T., Jr.
System: The UNT Digital Library
Dipole Moments of Diphenyl Compounds with Conjugated Double Bonds (open access)

Dipole Moments of Diphenyl Compounds with Conjugated Double Bonds

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.
System: The UNT Digital Library
A Reverberation Time Meter (open access)

A Reverberation Time Meter

This thesis describes the construction of an apparatus to measure reverberation time.
Date: 1950
Creator: Stockard, Raymond
System: The UNT Digital Library
Nonlinear UV Laser Build-up Cavity: An Efficient Design (open access)

Nonlinear UV Laser Build-up Cavity: An Efficient Design

Using the concept of the build-up cavity for second harmonic generation to produce 243nm laser light, an innovative cavity is theoretically explored using a 15mm length CLBO crystal. In order to limit the losses of the cavity, the number of effective optical surfaces is kept to only four and the use of a MgF2 crystal is adopted to separate the harmonic and fundamental laser beam from each other. The cavity is shown to have an expected round trip loss of five tenths of a percent or better, resulting in a conversion efficiency greater than 65%.
Date: May 2009
Creator: Rady, Nicholas Henry
System: The UNT Digital Library
Transport Phenomena in Indium Arsenide at Low Temperatures (open access)

Transport Phenomena in Indium Arsenide at Low Temperatures

This thesis looks at the transport phenomena in indium arsenide at low temperatures.
Date: August 1968
Creator: Luke, Paul Jacob
System: The UNT Digital Library
Application of the Wigner Formalism to a Slightly Relativistic Quantum Plasma (open access)

Application of the Wigner Formalism to a Slightly Relativistic Quantum Plasma

A slightly relativistic fermion gas is described by the dynamical theory obtained from the Wigner distribution function. The problem is approached in a self-consistent manner including the two-body Darwin Hamiltonian. The goal is to find the departures from equilibrium and dispersion relations for wave propagation in the gas.
Date: August 1967
Creator: Harper, John H.
System: The UNT Digital Library
A Study and Critique of the Mean Position Concept in Relativistic Wave Mechanics (open access)

A Study and Critique of the Mean Position Concept in Relativistic Wave Mechanics

The basic concept to be used in studying the question of one-particle interpretations of relativistic wave equations is that of observables and operator representations that are different from the more usual classically motivated observables and representations. In particular, the concept of a mean-position observable will be used to determine to what extent the one-particle "problems" can be resolved.
Date: January 1967
Creator: Gebhart, Hugh David
System: The UNT Digital Library
Homogeneous Canonical Formalism and Relativistic Wave Equations (open access)

Homogeneous Canonical Formalism and Relativistic Wave Equations

This thesis presents a development of classical canonical formalism and the usual transition schema to quantum dynamics. The question of transition from relativistic mechanics to relativistic quantum dynamics is answered by developing a homogeneous formalism which is relativistically invariant. Using this formalism the Klein-Gordon equation is derived as the relativistic analog of the Schroedinger equation. Using this formalism further, a method of generating other relativistic equations (with spin) is presented.
Date: January 1967
Creator: Jackson, Albert A.
System: The UNT Digital Library
Galvanomagnetic Determination of Energy Bands in Arsenic (open access)

Galvanomagnetic Determination of Energy Bands in Arsenic

A study of the transport properties of a substance requires the determination of a set of transport coefficients by experiment. From these coefficients, the elements of the electrical conductivity tensor, thermoelectric tensor, et cetera can be determined. In this experiment, measurements and analyses of galvanomagnetic effects in a single crystal of arsenic were performed. The measurements were made at liquid-helium temperatures in magnetic fields ranging to 25 kilogauss. The gross isothermal, electrical conductivities have been analyzed to determine various parameters characterizing the energy bands in arsenic.
Date: January 1968
Creator: Hathcox, Kyle Lee
System: The UNT Digital Library