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Microwave Properties of Hyaluronate Solutions Using a Resonant Microwave Cavity as a Probe

Description: Physiological functions of a biomacromolecule seem to be closely related to its molecular conformations. The knowledge of any conformational changes due to changes in its environment may lead to a proper understanding of its functions. Hyaluronic acid, a biomacromolecule with unusually high molecular weight and some important biological functions is the subject of the present work. A temperature-dependent transition in hyaluronate solution of 120 mg/ml concentration was observed at physiologica… more
Date: May 1980
Creator: Jani, Shirish K.
Item Type: Refine your search to only Thesis or Dissertation
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Phase Transition Studies in Polar and Nonpolar Liquids at Microwave Frequencies

Description: A resonant microwave cavity technique was employed to study the dielectric behavior of some polar and non-polar liquids near the phase transition temperatures at microwave frequencies of 7.2, 9.2 and 10.1 GHz. The Slater perturbation equations for a resonant microwave cavity are briefly discussed to show that the above technique can be used to determine both the real and imaginary parts of dielectric response. Abrupt changes in dielectric response were observed near the phase transition tempera… more
Date: August 1980
Creator: Dahiya, Jai N. (Jai Narain)
Item Type: Refine your search to only Thesis or Dissertation
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The Size Effect on the Galvanomagnetic Properties of a Semiconductor

Description: A theory is developed to explain the dependence of carrier transport in a thin semiconducting film on film thickness, magnetic field strength, and the dominant bulk scattering mechanism. This theory is based on the solution of the linearized Boltzmann equation in relaxation time form. The semiconductor is assumed to be bounded and nondegenerate with spherical energy surfaces and a scalar effective mass, It is also assumed to be flat banded with totally diffuse scattering at the surface. Classic… more
Date: August 1980
Creator: Smith, V. Devon (Vernon Devon)
Item Type: Refine your search to only Thesis or Dissertation
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Test of Gauge Invariance: Charged Harmonic Oscillator in an Electromagnetic Field

Description: 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 probabil… more
Date: August 1980
Creator: Wen, Chang-tai
Item Type: Refine your search to only Thesis or Dissertation
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A Collisional Mechanism in the Ion-Solid Interaction Which Enhances Scattering Yields Near 180⁰

Description: In the course of experiments using uniaxial double alignment channeling to investigate radiation damage in single crystals, an anomalously large ion-scattering yield from the near surface of disordered or simulated disordered solid targets was observed. The chronology of the discovery of this new ion-solid effect and its explanation are presented along with experiments detailing the dependence of the new effect upon ion type and energy, as well as target atomic number and density. Targets inclu… more
Date: December 1980
Creator: Holland, Orin Wayne
Item Type: Refine your search to only Thesis or Dissertation
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Low-Velocity K-Shell Ionization Cross Sections for Protons, Deuterons and Alpha Particles Bombarding Thin Metal Targets

Description: The purpose of this work was to examine the effect of the use the assumption κω2K/ΕCM «1 in calculating K-shell ionization cross sections in the plane wave Born approximation (PWBA) where κω2K is the observed binding energy of the K-shell and ECM is the energy of the incident particle in the center of mass system. Avoiding this assumption produces a threshold for ionization at Ecm = κω2K. Calculations employing the assumption, which leads to the use of approximate limits of integration, do not … more
Date: May 1981
Creator: Rice, Roger Karl
Item Type: Refine your search to only Thesis or Dissertation
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Picosecond Measurement of Nonlinear Diffusion and Recombination Processes in Germanium

Description: A variation of the excite-and-probe technique is used to measure the picosecond evolution of laser-induced transient gratings that are produced in germanium by the direct absorption of 40 psec optical pulses at 1.06-μm. Grating lifetimes are determined for free carrier densities between 10¹⁸ cm⁻³ and 10²¹ cm⁻³ . For carrier densities less than 10¹⁹ cm⁻³ , a linear diffusion-recombination model for the grating provides a good fit to the experimental data and allows the extraction of the diffusio… more
Date: May 1981
Creator: Moss, Steven Charles
Item Type: Refine your search to only Thesis or Dissertation
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Linewidth Parameters, Dipole Moments, and Microwave Spectrum of Nitrogen-Substituted Methyl Cyanide

Description: The shape of collision-broadened microwave absorption lines is reviewed, along with a number of other broadening mechanisms. The Anderson and Murphy-Boggs linewidth theories are reviewed in detail. Several published modifications to these theories are reviewed. Computer programs which numerically evaluate linewidths and lineshifts are presented. Approximations are made to reduce the need for extensive use of the modified Bessel functions, thereby reducing computation time. Only dipole-dipole f… more
Date: August 1981
Creator: Messer, James Keith
Item Type: Refine your search to only Thesis or Dissertation
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Photoconductivity Investigation of Two-Photon Magneto-Absorption, PACRH, and Deep Levels in n-InSb

Description: A high resolution photoconductivity investigation of two 13 -3 photon magneto-absorption (TPMA) in n-InSb (n - 9 x 10 cm ) has been performed. This is the first time that two-photon absorption in a semiconductor has been studied with cw lasers only. With a stable cw CC>2 laser and a highly sensitive sampling and magnetic field modulation technique, a minimum of 4 2 transitions in the TPMA photoconductivity spectra can be observed. Most of these transitions are a result of the usual spherical ap… more
Date: May 1982
Creator: Goodwin, Mike Watson
Item Type: Refine your search to only Thesis or Dissertation
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Infrared-Microwave Double Resonance Probing of the Population-Depopulation of Rotational States in the NO₂ and the SO₂ Molecules

Description: A 10.6 ym C02 laser operating a power range S P 200 watts was used to pump some select vibrational transitions in the NO2 molecule while monitoring the rotational transitions (91/9—'100/10), (232f 22 ~~"*242,23> ' (402,38 "393,37) in the (0, 0, 0) vibrational level and the (8q,8—*"^1,7) rotational transition in the (0, 1, 0) vibrational level. These rotational transitions were monitored by microwave probing to determine how the population of states in the rotational manifolds were being altered… more
Date: December 1982
Creator: Khoobehi, Bahram
Item Type: Refine your search to only Thesis or Dissertation
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Investigation of the Interaction of CO Laser Radiation with n-InSb

Description: The Shubnikov-de Haas magneto-resistance oscillations and photoconductivity were experimentally studied in order to investigate the interaction of CO laser radiation with n-InSb at liquid helium temperatures. The roles of various absorption mechanisms on these effects were considered, particularly near the intrinsic band edge. From these measurements an effective electron temperature Tₑ was defined that increased or decreased under illumination, depending upon the strength of the applied electr… more
Date: December 1982
Creator: Hanes, Larry Kenneth
Item Type: Refine your search to only Thesis or Dissertation
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M-Shell X-Ray Production of Gold, Lead, Bismuth, Uranium for Incident Hydrogen, Helium and Fluorine Ions

Description: Incident ¹H⁺ and ⁴He⁺ ions at 0.3-2.6 MeV and ¹⁹F^q⁺ ions at 25, 27 and 35 MeV were used to study the M-shell x-ray production cross sections of Au, Pb, Bi and U. For the incident fluorine ions, projectile charge state dependence of the cross sections were extracted from measurements made with varying target thicknesses ( ~1 to ~300 μg/cm²). The efficiency of the Si(Li) detector was determined by measuring the K-shell x-ray production of various low Z elements and comparing these values to the … more
Date: December 1982
Creator: Mehta, Rahul
Item Type: Refine your search to only Thesis or Dissertation
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Operator Gauge Transformations in Nonrelativistic Quantum Electrodynamics

Description: A system of nonrelativistic charged particles and radiation is canonically quantized in the Coulomb gauge and Maxwell's equations in quantum electrodynamics are derived. By requiring form invariance of the Schrodinger equation under a space and time dependent unitary transformation, operator gauge transformations on the quantized electromagnetic potentials and state vectors are introduced. These gauge transformed potentials have the same form as gauge transformations in non-Abelian gauge field … more
Date: December 1982
Creator: Gray, Raymond Dale
Item Type: Refine your search to only Thesis or Dissertation
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Picosecond Laser-Induced Transient Gratings and Anisotropic State-Filling in Germanium

Description: We present a comparative theoretical study of the transient grating coherent effects in resonant picosecond excitation-probe experiments. Signals in both the probe and conjugate directions are discussed. The effects of recombination, non-radiative scattering and spatial and orientational diffusion are included. The analysis is applied to both a molecular and to a semiconductor model. Signal contributions from concentration and orientational gratings are distinguished and their temporal natures … more
Date: December 1982
Creator: Boggess, Thomas F. (Thomas Frederick)
Item Type: Refine your search to only Thesis or Dissertation
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Theoretical and Experimental Linewidth Parameters in the Rotational Spectrum of Nitrogen Dioxide

Description: Contributions to the second order collision efficiency function S ⁽²⁾ (b), used in semiclassical perturbation approaches to pressure broadening of microwave and infrared spectra, due to several leading terms, dipole and quadrupole components, in the expansion of the intermolecular interaction energy are derived by method of irreducible spherical tensor operators for molecules of arbitrary symmetry. Results are given explicitly in terms of dipole and quadrupole line strengths. General expression… more
Date: December 1982
Creator: Moazzen-Ahmadi, Mohamad Nasser
Item Type: Refine your search to only Thesis or Dissertation
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The Effect of Intervalence-Band Absorption, Auger Recombination, Surface Recombination, Diffusion and Carrier Cooling on the Picosecond Dynamics of Laser-Induced Plasmas in Germanium

Description: The picosecond optical response of germanium is investigated by performing excitation-probe experiments on a thin, intrinsic-germanium wafer maintained at 135 K. The results of three distinct experiments are reported: (1) the transmission of a single pulse is measured as a function of irradiance, (2) the probe transmission is measured at a fixed time after excitation as a function of the excitation energy, and (3) the transmission of a probe pulse is monitored as a function of time after excita… more
Date: May 1983
Creator: Lindle, James Ryan
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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A Gauge-Invariant Energy Variational Principle Application to Anisotropic Excitons in High Magnetic Fields

Description: A new method is developed for treating atoms and molecules in a magnetic field in a gauge-invariant way using the Rayleigh-Ritz energy variational principle. The energy operator depends on the vector potential which must be chosen in some gauge. In order to adapt the trial wave function to the gauge of the vector potential, the trial wave function can be multiplied by a phase factor which depends on the spatial coordinates. When the energy expectation value is minimized with respect to the phas… more
Date: December 1983
Creator: Kennedy, Paul K. (Paul Kevin)
Item Type: Refine your search to only Thesis or Dissertation
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Degenerate Four Wave Mixing of Short and Ultrashort Light Pulses

Description: This dissertation presents experimental and theoretical studies of transient degenerate four wave mixing (DFWM) in organic dyes. Chapter 1 is an introduction to DFWM. Chapter 2 describes DFWM experiments that were performed in the gain medium of a dye laser. Chapter 3 presents the theory of DFWM of short pulses in three level saturable media. Chapter 4 presents DFWM experiments of femtosecond pulses in the saturable absorber of a passively modelocked ring dye laser. Chapter 5 presents the theor… more
Date: August 1984
Creator: McMichael, Ian C. (Ian Charles)
Item Type: Refine your search to only Thesis or Dissertation
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Picosecond Measurement of Interband Saturation, Intervalence Band Absorption, and Surface Recombination in Germanium

Description: The picosecond optical response of five thin germanium samples was measured following intense optical excitation using two variations of the excitation and probe technique. Seven-picosecond laser pulses of wavelength 1.054 um were used to measure the optical transmission of the samples for a variety of probe delays, excitation fluences, and sample temperatures. These parametric experiments were performed in an effort to determine if carrier cooling, carrier diffusion, or carrier recombination d… more
Date: August 1984
Creator: Perryman, Gary Paul
Item Type: Refine your search to only Thesis or Dissertation
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Parametric Studies of Picosecond Laser-Induced Breakdown in Fused Quartz and NaCl

Description: Bulk laser-induced breakdown and self-focusing in single samples of fused quartz and NaCl were examined using picosecond optical pulses at 1.0 ym and 0.5 ym. The results of three separate but related experiments are reported. First the nonlinear index of refraction, n2, of each of the test materials is measured near the respective damage thresholds of the samples. The values of 1*2 were determined by detecting beam distortions in the far field, transmitted laser beam profile caused by the irrad… more
Date: December 1984
Creator: Williams, William Ely
Item Type: Refine your search to only Thesis or Dissertation
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Nonlinear Absorption Techniques and Measurements in Semiconductors

Description: We have conducted a detailed experimental and theoretical study of nonlinear absorption in semiconductors. Experimental measurements were made on a variety of materials at wavelengths of 1.06 and 0.53 microns using a picosecond Nd:YAG laser. Both two- and three-photon processes were investigated. Values of nonlinear absorption coefficients extracted from these measurements show excellent agreement with recent theory and scaling rules. Our theoretical investigation has been carried out for two-,… more
Date: August 1985
Creator: Woodall, Milton Andrew
Item Type: Refine your search to only Thesis or Dissertation
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The Rotational Spectra of Propyne in the Ground, V₁₀=1, V₁₀=2, and V₉=1 Vibrational States

Description: The problem of a vibrating-rotating polyatomic molecule is treated, with emphasis given to the case of molecules with C_3v symmetry. It is shown that several of the gross features of the rotational spectra of polyatomic molecules in excited vibrational states can be predicted by group theoretical considerations. Expressions for the rotational transition frequencies of molecules of C_3v symmetry in the ground vibrational state, singly excited degenerate vibrational states, and doubly excited deg… more
Date: August 1985
Creator: Ware, John Matthew
Item Type: Refine your search to only Thesis or Dissertation
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Electron-Ion Time-of-Flight Coincidence Measurements of K-K Electron Capture, Cross Sections for Nitrogen, Methane, Ethylene, Ethane, Carbon Dioxide and Argon (L-K) Targets

Description: Protons with energies ranging from 0.4 to 2.0 MeV were used to measure K-shell vacancy production cross sections (oVK) for N_2, CH_4, C_2H_4, C_2H_6, and CO_2 gas targets under single collision conditions. An electron-ion time-of-flight coincidence technique was used to determind the ration of the K-K electron capture cross section, OECK, to the K-vacancy production cross section, oVK. These ratios were then combined with the measured values of oVK to extract the K-K electron capture cross sect… more
Date: May 1986
Creator: Toten, Arvel D.
Item Type: Refine your search to only Thesis or Dissertation
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