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

Description: 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… more
Date: May 1983
Creator: Franck, Jerome B. (Jerome Bruce)
Item Type: Refine your search to only Thesis or Dissertation
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Automatic Frequency Control of Microwave Radiation Sources

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.
Date: August 1979
Creator: Payne, Bobby D.
Item Type: Refine your search to only Thesis or Dissertation
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The Classical Limit of Quantum Mechanics

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 s… more
Date: December 1977
Creator: Hefley, Velton Wade
Item Type: Refine your search to only Thesis or Dissertation
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Shubnikov-de Haas Effect Under Uniaxial Stress: A New Method for Determining Deformation Potentials and Band Structure Information in Semiconductors

Description: The problem with which this investigation is concerned is that of demonstrating the applicability of a particular theory and technique to two materials of different band structure, InSb and HgSe, and in doing so, determining the deformation potentials of these materials. The theory used in this investigation predicts an inversion-asymmetry splitting and an anisotropy of the Fermi surface under uniaxial stress. No previous studies have ever verified the existence of an anisotropy of the Fermi su… more
Date: December 1972
Creator: Hathcox, Kyle Lee
Item Type: Refine your search to only Thesis or Dissertation
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Microwave Properties of Liquids and Solids, Using a Resonant Microwave Cavity as a Probe

Description: The frequency shifts and Q changes of a resonant microwave cavity were utilized as a basis for determining microwave properties of solids and liquids. The method employed consisted of varying the depth of penetration of a cylindrical sample of the material into a cavity operating in the TM0 1 0 Mode. The liquid samples were contained in a thin-walled quartz tube. The perturbation of the cavity was achieved by advancing the sample into the cavity along the symmetry axis by employing a micrometer… more
Date: May 1974
Creator: Hong, Ki H.
Item Type: Refine your search to only Thesis or Dissertation
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Theoretical Cross Section for Light Scattering from Superfluid Helium-4

Description: The finite lifetime of the bound roton pair is included in the theoretical light scattering cross section to explain the shape of the peak in the observed Raman light scattering cross section in He II. A model Hamiltonian is used to describe interactions between quasiparticles for the helium system. The equation of motion for the bound roton pair state, which is taken to be a collective mode of quasiparticle pairs, is solved. The cross section for light scattering is then derived using Fermi's … more
Date: May 1976
Creator: Latham, W. Peters, Jr., 1948-2016.
Item Type: Refine your search to only Thesis or Dissertation
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A Study of L-Shell X-Ray Production Cross Sections Due to [Hydrogen-1], [Helium-4], and [Lithium-7] Ion Bombardment of Selected Thin Rare Earth and ₈₂Pb Targets

Description: Thin target L-Shell x-ray production cross sections for protons incident on ₆₂Sm and ₇₀Yb in the energy range of 0.3 to 2.4 MeV/amu, alpha particles incident on ₆₂Sm, ₇₀Yb, and ₈₂Pb in the energy range of 0.15 to 4.8 MeV/amu, and lithium ions incident on ₅₈Ce, ₆₀Nd, ₆₂Sm, ₆₆Dy, ₆₇Ho, ₇₀Yb, and ₈₂Pb in the energy range of 0.8 to 4.4 MeV/amu have been measured. The cross section data have been compared to the planewave Born approximation (PWBA) and the PWBA modified to include binding energy and … more
Date: May 1978
Creator: Light, Glenn Michael
Item Type: Refine your search to only Thesis or Dissertation
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K-Shell Ionization Cross Sections of Selected Elements from Fe to As for Proton Bombardment from 0.5 to 2.0 MeV

Description: The problem with which this investigation is concerned is that of making experimental measurements of proton-induced K-shell x-ray production cross sections and to study the dependence of these cross sections upon the energy of the incident proton. The measurements were made by detection of the characteristic x-rays emitted as a consequence of the ionization of the K-shell of the atom. The method for relating this characteristic x-ray emission to the x-ray production cross section is discussed … more
Date: December 1973
Creator: Lear, Richard Dean
Item Type: Refine your search to only Thesis or Dissertation
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The Shubnikov-de Haas Effect in N-Type Indium Antimonide

Description: The Shubnikov-de Haas effect is an oscillation in the electrical resistivity or conductivity of a metal, semimetal, or semiconductor as a function of changing magnetic field which occurs at low temperatures. The effect is caused by the quantization of the momentum and energy of the charge carriers by the magnetic field. Since the nature of the oscillation depends strongly on the energy band structure of the material in which it is measured, the effect could be quite useful as an investigative t… more
Date: August 1975
Creator: Stephens, Anthony Earl
Item Type: Refine your search to only Thesis or Dissertation
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K-Shell Ionization Cross Sections For Elements Se To Pd: 0.4 To 2.0 MeV

Description: K-Shell ionization cross section for protons over the energy range of 0.4 to 2.0 MeV have been measured on thin targets of the elements Se, Br, Rb, Sr, Y, Mo and Pd. Total x-ray and ionization cross sections for the K-shell are reported. The experimental values of the ionization cross sections are compared to the non-relativistic plane-wave Born approximation, the binary-encounter approximation, the constrained binary-encounter approximation, and the plane-wave Born approximation with correctio… more
Date: December 1974
Creator: Criswell, Tommy L.
Item Type: Refine your search to only Thesis or Dissertation
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Collision Broadening of Microwave Spectral Lines of Monomeric Formaldehyde and Formic Acid

Description: Line width parameters for a number of spectral lines in the pure rotational spectrum of formaldehyde (CH20) and formic acid (HCOOH) have been measured using a sourcemodulated microwave spectrograph. All transitions studied in this investigation were of the type ΔJ=O (i.e. Q-branch transitions), with ΔK-1=0 and ΔK+1 =+l. The center frequencies of the measured lines varied from 8662.0 MHz to 48612.70 MHz. The experimentally determined collision diameters for self broadening interactions involving… more
Date: August 1975
Creator: Venkatachar, Arun C.
Item Type: Refine your search to only Thesis or Dissertation
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A Classical Theory of the Dielectric Susceptibility of Anharmonic Crystals

Description: An expression for the dielectric susceptibility tensor of a cubic ionic crystal has been derived using the classical Liouville operator. The effect of cubic anharmonic forces is included as a perturbation on the harmonic crystal solution, and a series expansion for the dielectric susceptibility is developed. The most important terms in the series are identified and summed, yielding an expression for the complex susceptibility with an anharmonic contribution which is linearly dependent on temper… more
Date: May 1976
Creator: Kennedy, Howard V.
Item Type: Refine your search to only Thesis or Dissertation
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Calculations of Nuclear Energies Using the Energy Density Formalism

Description: The energy density formalism (EDF) is used to investigate two problems. The EDF is a phenomenological method that incorporates as much knowledge of infinite nuclear matter as possible. In this formalism the energy of the nucleus is expressed as a functional of its density. The nucleus energy is obtained by minimizing the function, with respect to the density. In this report, the EDF is used to investigate the mercury isotope shift anomaly following the aforementioned suggestion. Specifically, n… more
Date: August 1975
Creator: Pu, William Wei-Ta
Item Type: Refine your search to only Thesis or Dissertation
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L X-Ray Production in the Rare Earths by 0.33-2.66-MeV/amu Carbon- and 0.50-2.25-MeV/amu Oxygen-Ion Bombardment

Description: Experimentally measured L-shell x-ray production cross sections are presented for 8-36-MeV oxygen-ion bombardment of Ce, Pr, Sm, Eu, Dy, and Ho; for 4-32-MeV carbon-ion bombardment of La and Yb; for 6-32-MeV carbon-ion bombardment of Pr, Nd, Sm, and Dy; and for ll-29-MeV carbon-ion bombardment of Ce, Eu, Gd, and Ho. Theoretical predictions via the plane wave Born approximation (PWBA) with corrections for increased binding of target electrons and Coulomb deflection of the incident projectile ten… more
Date: August 1975
Creator: Pepper, George H.
Item Type: Refine your search to only Thesis or Dissertation
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Collision Broadening in the Microwave Rotational Spectrum of Gaseous Monomeric Formaldehyde

Description: A source-modulation microwave spectrograph was utilized to measure line width parameters for several spectral lines in the pure rotational spectrum of formaldehyde (H₂CO). The spectrograph featured high-gain ac amplification and phase-sensitive detection, and was capable of measuring microwave lines having absorption coefficients as small as 10⁻⁷ cm⁻¹ with a frequency resolution on the order of 30 kHz. Center frequencies of the measured lines varied from 4,830 MHz to 72,838 MHz; hence, most of … more
Date: December 1973
Creator: Rogers, David Valmore
Item Type: Refine your search to only Thesis or Dissertation
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Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy

Description: Characteristic L-shell x rays of the five rare earths Pr, Sm, Eu, Gd, and Dy were studied in this work. The x rays were produced by ionization from 0.3 to 2.0 MeV protons from the 2.0 MV Van de Graaff at North Texas State University. Total L-shell ionization and x-ray production cross sections were measured for Sm and compared to the BEA, CBEA and PWBA theories. Total L-shell ionization cross sections were measured for Pr, Eu, Gd, and Dy and compared to the BEA, CBEA, and PWBA. The CBEA and PW… more
Date: August 1974
Creator: Abrath, Frederick G.
Item Type: Refine your search to only Thesis or Dissertation
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