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**Partner:**UNT Libraries

**Degree Discipline:**Physics

**Degree Level:**Master's

**Collection:**UNT Theses and Dissertations

### Nonlinear UV Laser Build-up Cavity: An Efficient Design

**Date:**May 2009

**Creator:**Rady, Nicholas Henry

**Description:**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%.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc9833/

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

**Date:**December 1994

**Creator:**Bickel, David, 1970-

**Description:**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.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc279387/

### Automatic Frequency Control of Microwave Radiation Sources

**Date:**August 1979

**Creator:**Payne, Bobby D.

**Description:**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.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc504304/

### The Classical Limit of Quantum Mechanics

**Date:**December 1977

**Creator:**Hefley, Velton Wade

**Description:**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.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc504591/

### Effects of Discharge Tube Geometry on Plasma Ion Oscillations

**Date:**May 1975

**Creator:**Simmons, David Warren

**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 along with possible explanations for the observed phenomena. Suggestions for future study are made.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc663636/

### Microwave Line Widths of the Asymmetric Top Formic Acid Molecule

**Date:**August 1974

**Creator:**Maynard, Wayne R.

**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 found to be larger than the physical size of the molecule. This result was found to be in general agreement with other investigation in which long range forces (dipole-dipole) dominate.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc663604/

### Relaxation Time Measurements for Collision Processes in the Surface Layers of Conductors and Semiconductors Near 10 Ghz

**Date:**December 1973

**Creator:**Childress, Larry Wayne

**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 it.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc663566/

### 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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**Permallink:**digital.library.unt.edu/ark:/67531/metadc164055/

### A Decay Scheme for 164 Ho

**Date:**December 1972

**Creator:**Guertin, James

**Description:**The present investigation was prompted by several considerations. In previous studies there was considerable variance with regard to the reported values for the half-lives of the isomeric and ground states in 164 Ho. There was also considerable variance with regard to the values reported for the branching ratios and the relative intensities of the transitions. Thus a further study of the problem was needed.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131582/

### Pressure Dependence of Line Widths of Microwave Spectra of Sulphur Dioxide

**Date:**December 1972

**Creator:**Yang, Wei Han

**Description:**Measurements of line width parameters for eleven rotational transitions of type (J -- J + 1) of SO2 were made and are reported herein. The line width quantum number (J) trend was obtained. The microwave spectrograph used for these measurements of line width is described. Operational methods to operate the spectrograph are presented and discussed, with particular attention given to how to measure the line width. Suggestions for future avenues of probing this molecule to ascertain the non-uniform behavior of the line width parameter over the quantum number and frequency range are given.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131591/

### Quantized Hydrodynamics

**Date:**August 1972

**Creator:**Coomer, Grant C.

**Description:**The object of this paper is to derive Landau's theory of quantized hydrodynamics from the many-particle Schroedinger equation. Landau's results are obtained, together with an additional term in the Hamiltonian.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131535/

### Virial Theorem for a Molecule

**Date:**May 1972

**Creator:**Ranade, Manjula A.

**Description:**The usual virial theorem, relating kinetic and potential energy, is extended to a molecule by the use of the true wave function. The virial theorem is also obtained for a molecule from a trial wave function which is scaled separately for electronic and nuclear coordinates.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131519/

### Cross Section Measurements in Praseodymium-141 as a Function of Neutron Bombarding Energy

**Date:**May 1971

**Creator:**Marsh, Stephen Addison

**Description:**Using the parallel disk method of activation analysis, the (n,2n) reaction cross section in 141-Pr was measured as a function of neutron energy in the range 15.4 to 18.4 MeV. The bombarding neutrons were produced from the 3-T(d,n)4-He reaction, where the deuterons were accelerated by the 3-MV Van de Graff generator of the North Texas Regional Physics Laboratory in Denton, Texas.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131376/

### Phase Shift Determination for Elastic Potential Scattering, Using the IBM 360-50 Computer

**Date:**May 1971

**Creator:**Psencik, James A.

**Description:**The primary objective of this paper is to present a computerized method for the extraction of phase shifts from an angular distribution. This was accomplished using a least squares curve fitting routine.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131381/

### Carbon Contamination Measurements in Single Silicon Crystals

**Date:**December 1970

**Creator:**Logsdon, Lawrence E.

**Description:**The intent of this investigation was to directly measure the amount of carbon contamination in a single silicon crystal and, in so doing, develop a mathematical procedure that would be applicable to other contaminants in other substances.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131331/

### Nuclear Reactions on the Palladium Isotopes

**Date:**December 1970

**Creator:**White, Ronald Lee

**Description:**The problem of interest in this investigation was to determine the cross sections of five nuclear reactions which occur when irradiating natural palladium with neutrons which have energy values of 15.1, 15.9, and 16.3 MeV. The cross sections were measured relative to a copper monitor which was "sandwitched" in with the palladium target.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131351/

### A Study of the Decay Levels of 169/Tm69

**Date:**December 1970

**Creator:**Harris, Robert J.

**Description:**The purpose of this investigation was to study the radiations of the 169/Tm nucleus as it de-excites after the electron capture decay of the 169/Yb. Numerous unreported gammas were present in the sample. The origins of these gamma rays were found.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131328/

### The Effects of Lead Placement and Sample Shape in the Measurement of Electrical Resistivity

**Date:**August 1970

**Creator:**Stephens, Anthony E.

**Description:**This thesis is a study of the effects of lead placement and sample shape in the measurement of electrical resistivity.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131303/

### Measurement of the Atomic-oxygen Concentration under Simulated Upper Atmosphere Conditions

**Date:**January 1970

**Creator:**Grable, Weliko C.

**Description:**This thesis describes an experimental technique for measuring the atomic-oxygen concentration under simulated upper atmosphere conditions.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131196/

### A Precision Angular Correlation Table and Calculation of Geometrical Correction Factors

**Date:**January 1970

**Creator:**Rowton, Larry James

**Description:**In recent years y-y angular correlations have been very useful in confirming the spins of excited nuclear states. Angular correlation techniques have also been employed to study the electric and magnetic character of excited nuclear states. With these things in mind, it was decided to design, construct, and test a precision angular correlation table.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131220/

### Cross Section for the 165/Ho (n, 2n) 164/Ho Reaction at 15.6 MeV

**Date:**August 1969

**Creator:**Lear, Richard D.

**Description:**It was the purpose of this investigation to bring together the ideas and procedures involved in the measurement of (n, 2n) reaction cross sections. Some of the inherent properties of the material under investigation (Holium) are involved in determining these relationships.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131148/

### Electron Spin Resonance Absorption in Benzophenone Phenylhydrazone Negative Ion

**Date:**August 1969

**Creator:**Oral, Burhanettin

**Description:**This thesis reports an electron spin resonance absorption study of the hyperfine interaction between nuclei and a single "nearly-free" electron in dilute solutions of the benzophenone phenylhydrazone free radical in tetrahydrofuran.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131161/

### Magnetomorphic Oscillations in Cadmium Cylinders

**Date:**August 1969

**Creator:**Hight, Ralph D.

**Description:**The work presented here is an experimental investigation of the effect of cylindrical geometry on electrical conductivity, in which single-crystal samples of cadmium at the temperature of liquid helium are used, with the diameter on the order of the electron mean free path.

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc131138/

### Microwave Cavity Method for Measuring Plasma Properties

**Date:**August 1969

**Creator:**Freeman, Ronald H.

**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 simulate a plasma model that will be of interest for hypervelocity reentry vehicles and to provide meaningful expressions for the various plasma parameters of interest (electron density, electron temperature, collision frequency, etc.) in terms of the microwave measurables (amplitude, phase shifts, frequency shifts, polarization, etc.)

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**Permallink:**digital.library.unt.edu/ark:/67531/metadc163950/