Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 50).

Thesis (M.S.)--Ohio State University, 1980. / Includes bibliographical references (leaves 100-104). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 291-301).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 200-205). Available also in a digital version from Dissertation Abstracts.

GaInAsP and GaInAs epitaxial layers grown on Fe-doped InP substrates of {100} orientation have been studied using cross-sectional and plan-view transmission electron microscopy. Studies of the epilayer surface regions of LPE Ga[0.03]In[0.97] As[0.07]P[0.93] heavily doped with Mn or Mn and Ge have revealed at least seven precipitate types when classification is made according to precipitate morphology, configurations and associated strain fields. The origin of some of these second phase particles is shown to be iron-phosphide precipitation resulting from iron diffusion from the substrate. Furthermore, in a LPE Ga[0.47]In[0.53]As layer co-doped with Mn and Ge four distinct precipitate types were observed. Speckle and long wavelength microstructures in GalnAs grown by LPE, MOCVD and MBE have been studied. A long wavelength microstructure lying along directions which is observed in some MBE GalnAs layers is associated with reduced electron mobilities. In MOCVD GalnAs a long wavelength microstructure lying along directions was seen to vary as a function of distance from the interface. The presence and wavelength of the speckle contrast is shown to be independent of the growth technique employed. Some MBE GalnAs layers also reveal an island contrast along orthogonal directions. Undoped MOCVD GalnAs epilayers with large compositional fluctuations approximately half way through the thickness of the epilayer or small compositional fluctuations near the epilayer surface have been studied. These perturbations in composition are associated with a dislocation cell structure and a cross-hatch of dislocations along directions respectively. A variety of defects have been identified and the microstructure correlated with Sputter Auger profiles and depth-resolved Hall profiles. Cliff-Lorimer k-factors have been determined experimentally and theoretically for Ga, As and P relative to In and extinction distances for GalnAs and InP calculated.

The work of this thesis is concerned, with the investigation and attempted improvement of an integral method for solving the two dimensional, incompressible laminar boundary layer equations of fluid dynamics. The method which is based on a theoretical two parameter representation of well-known boundary layer properties was first produced by Professor S. N. Curle. Its range of application, reliability and accuracy rely on four universal functions which have been derived from known exact solutions to the boundary layer equations, and are given tabulated in terms of a pressure gradient parameter λ. This thesis seeks to improve these properties by making adjustments to the tabulated functions and also considers the extension of the method to certain compressible boundary layer problems. The first chapter contains the development of, and background to the method and gives a critical assessment of the existing functions. This analysis indicates that the method may be improved by supplying more data for certain ranges of λ from which the functions may be calculated; by improving the fitting process; and by the provision for small values of λ of an analytic form for a shape parameter H which the method involves. To supply more data two new solutions for the flows u₁ = U₀ (1+ξ) and u₁ = u₀ (ξ+ξ³) where ξ is a non-dimensional co-ordinate in the direction of the flow, are investigated. The resulting work produces some interesting examples of the use of series expansions in boundary layer theory and these, and the results produced, are given in the second chapter. The fitting of the functions is carried out in chapter three. Polynomial models in terms of λ are fitted by least squares techniques to data from seven solutions and are adjusted to ensure an analytic form for H for small values of λ. A comparison of results using new and old tables Indicates that an improvement has been made. The transformation relating certain compressible and incompressible flows is next examined and the extension of the method to such problems considered. An idea due to Stewartson for assessing the relative accuracies of methods under such circumstances indicates that the method should be highly accurate, a result confirmed by the calculation of the compressible flow u₁ = u₀ (1-ξ) at a leading edge Mach number of four. The thesis is concluded with a review of the work carried out and the results obtained.

Made available in DSpace on 2016-06-02T19:19:58Z (GMT). No. of bitstreams: 1 CAMPOS_Paula_2014.pdf: 1924698 bytes, checksum: d5134f8bff1512ce41535c0a1f61d175 (MD5) Previous issue date: 2014-02-28 / Financiadora de Estudos e Projetos / In this work the immobilization of enzyme β-Galactosidase has been investigated with use of assembly technique of nanostructured films denominated LbL (Layer-by-Layer) for employment in an amperometric biosensor of lactose. Therefore, spectroscopy measured has made for UV-vis (Ultraviolet-visible) and fluorescence, in order to monitor the bands of absorption and emission of each bilayer deposited and to confirm the presence of enzyme in the films. It has made too FTIR (Fourier Transform Infrared Spectroscopy) and SFG (Sum Frequency Generation) for the purpose to understand the films structure, the interactions present and the efficiency of technique in the immobilization process. For the lactose detection amperometric measured have carried and that way the performance of modified electrode have evaluated in relation to enzyme immobilization, the polyelectrolytes performance Poly (allylamine hydrochloride) (PAH) and Poli (etileno imina) (PEI) and poly(ethyleneimine) and the operations conditions of biosensor which sensibility, limit of detection, interferences and stability. The evaluation of enzyme deposition by UV-vis and fluorescence showed that the films growth has been satisfactory presenting the characteristics bands of da β-Gal regarding to amino acid residues tryptophan, tyrosine and phenylalanine, among others, in λ = 280 nm for absorption and λ = 344 nm for emission and the deposition of material has been growing. The spectrum of FTIR and SFG indicated bands of chemical groups characteristics of polymers and enzyme and proved that the bonds, probably secondary of the elements are sufficiently strong for to keep the films in substrate during the sensory evaluation. In lactose detection it has made electrode of (PEI/β-Gal)n e (PAH/β-Gal)n both of ten and third bilayers. The sensibility of film (PEI/β-Gal)10 was 0.061 μA mmol-1 cm-2, while the (PAH/β-Gal)10 was 0.079 μA mmol-1 cm-2. In order to increase the efficiency of the biosensors, electrodes compounds for third bilayers were tested, this way the film (PEI/β-Gal)30 has achieved a sensibility higher than the previous electrodes of 0.31 μA mmol-1 cm-2, is likely that a great amount of enzyme has been immobilized. However, the film ITO/PB/(PAH/β-Gal)30 has not get the same efficiency despite de number of bilayer have been increase. Have been identified two interferences, the glucose and the ascorbic acid, but both can be avoided, the first with use of a biosensor for glucose coupled with lactose biosensor and the second causes an elevation on current, being naturally differentiated. The stability of the biosensor was twelve days, being measured in days alternate. All experiments performed to converge to prove that the LbL technique were adequate to assembly the biosensor and that lactose detection can be done and in levels nearby to real samples, but is possible to improve the system still with studies more expanders about the films structure and to test news biosensors configurations. / Neste trabalho investigou-se a imobilização da enzima β-Galactosidase utilizando a técnica de automontagem de filmes nanoestruturados, denominada LbL (Layer-by-Layer do inglês) para o emprego em um biossensor amperométrico de lactose. Foram feitas medidas espectroscópicas por Ultravioleta e visível (UV-vis) e fluorescência, a fim de monitorar as bandas de absorção e emissão de cada bicamada depositada e confirmar a presença da enzima nos filmes. Fez-se também espectroscopia por transformada de Fourier (FTIR) e Geração de Soma de Frequências (SFG) para compreender a estrutura dos filmes, as interações presentes e a eficiência da técnica no processo de imobilização. Para a detecção de lactose realizou-se medidas amperométricas e dessa forma avaliou-se o desempenho do eletrodo modificado em relação à imobilização da enzima, a eficiência dos polieletrólitos Poli (alilaminahidroclorada) (PAH) e Poli (etileno imina) (PEI) e as condições de operação do biossensor tais como sensibilidade, limite de detecção, interferentes e estabilidade. A avaliação da deposição da enzima pelo UV-vis e fluorescência mostrou que o crescimento dos filmes foi satisfatório, apresentando as bandas características da β-Gal atribuídas aos resíduos de aminoácidos triptofano, tirosina e fenilalanina, entre outros, em λ = 280 nm por absorção e sendo os mesmo responsáveis pela emissão em λ = 344 nm sendo que a deposição de material foi crescente. Os espectros de FTIR e SFG indicaram bandas de grupamentos químicos característicos dos polímeros e da enzima e comprovaram que as interações, provavelmente secundárias, entre os elementos são fortes o suficiente para manter o filme no substrato durante as avaliações sensoriais. Na detecção de lactose foram feitos eletrodos de ITO/PB/(PEI/PVS)1/(PEI/β-Gal)n e ITO/PB/(PAH/PVS)1/(PAH/β-Gal)n ambos com dez e trinta bicamadas. A sensibilidade do filme ITO/PB/(PEI/PVS)1/(PEI/β-Gal)10 foi 0,061 μA.mmol-1.cm-2, enquanto o ITO/PB/(PAH/PVS)1/(PAH/β-Gal)10 foi 0,079 μA.mmol-1.cm-2. A fim de aumentar a eficiência do biossensor eletrodos compostos por 30 bicamadas foram testados, dessa forma o filme ITO/PB/(PEI/PVS)1/(PEI/β-Gal)30 alcançou uma sensibilidade superior aos eletrodos anteriores de 0,31 μA.mmol-1.cm-2, pois é possível que uma maior quantidade de enzimas tenha sido imobilizada. Entretanto o filme ITO/PB/(PAH/PVS)1/ (PAH/β-Gal)30 não obteve a mesma eficiência mesmo tendo o número de bicamadas aumentado, o que pode ser atribuído à estrutura do polieletrólito. Foram identificados dois interferentes, a glicose e o ácido ascórbico, mas ambos podem ser evitados, o primeiro com o uso de um biossensor para glicose acoplado ao da lactose e o segundo causa uma elevação na corrente, sendo naturalmente diferenciado. A estabilidade do biossensor foi de 12 dias, com medida em dias alternados. Todos os experimentos realizados convergem para provar que a técnica LbL foi adequada para a construção do biossensor e que a detecção da lactose pode ser feita em níveis de concentração próximos à de amostras reais, mas ainda é possível aprimorar o sistema com estudos mais aprofundados sobre a estrutura dos filmes e testar novas configurações de biossensores.

Photoelectron spectroscopy, with LEED, Auger electron spectroscopy (AES) and secondary electron emission crystal current (SEECC) measurements, has been used to investigate the electronic structure of well-characterized overlayers of Tl, Cr, Mn and Fe on Ag(100) and Fe on Cu(100). The Stranski-Krastanov growth mode has been found for Tl on Ag(100). In the chain structure observed at 70 K, there is no evidence for a Peierls distortion, in contrast to Tl chains on Cu(100). Band-mapping of the Tl 6p band has indicated the absence of an energy gap at the Fermi level, confirming the LEED result that the Peierls distortion has been suppressed. This is believed to be due to commensurability with the substrate. A study of Cr on Ag(100) has revealed epitaxial growth up to two monolayers, with a transition to bilayers before the completion of the first layer. Photoemission measurements of the Cr 3s multiplet splitting indicate an enhanced magnetic moment, which approaches the bulk value with coverage. This enhancement is thought to be a consequence of d-band narrowing, resulting from the reduced dimensionality of the overlayer. A p(1 x 1) surface alloy is initially observed when Mn is deposited on Ag(100), but with a magnetic moment smaller than the bulk Mn value; angle-resolved photoemission measurements indicate significant overlayer- substrate d-d interaction, in contrast to Cr on Ag(100). With further coverage, the magnetic moment increases and when simultaneous multilayer growth occurs on the AgMn surface, the bulk value is attained. Pseudomorphic 1ayer-by-layer growth has been identified for Fe deposited on Cu(100) and the band structure has been determined for Fe coverages of one and seven monolayers. From a comparison with calculated band structures, it is proposed that the monolayer is ferromagnetic, while the thicker fee film may be antiferromagnetic. An Fe monolayer on Ag(100) has also been shown to have ferromagnetic order.