The electroreflectance spectra(ER) have been measured on InxGa1-xAs film under various bias(Vbias), and they have exhibited many Franz-Keldysh Oscillations(FKOs) above band-gap energy. Their strength of field in the film can be obtained by the periods of FKOs. Due to many oscillations of FKOs, the Fast Fourier transform can be applied to separate heavy- and light-hole transitions. The relation between F and Vbias was nearly linear. FKOs were observable at a large range of photon energy(£_E). The mean free path of carriers can be estimated from the relation between £_E and F. It was compared with the range of order obtained from X-ray diffraction.

In this study, the reactive rf magnetron sputtering was used to deposit zinc oxide (ZnO) thin films on Si substrate. The optimal sputtering parameters for film as luminescence application were found to be oxygen concentration (O2/O2+Ar) of 21%, RF power of 100W, substrate temperature of 500¢XC and sputtering pressure of 5 mtorr. Beside, the thermal treatment procedure was carried out to improve the luminescence characteristics of ZnO thin films. The physical characteristics of ZnO thin films deposited on Si substrate with different sputtering parameters were obtained by the analyses of XRD and SEM. The optical properties of ZnO thin films were discussed also. Ultraviolet (UV) visible spectrometer and photoluminescence spectrometer were used to measure the visible transmission and photoluminescence characteristics (PL), respectively. According to the experimental results, it is found that under optimal sputtering parameters, the emitted UV light intensity will be increased as the FWHM in x-ray diffraction is decreased, i.e. the grain size is larger. In addition, after post-deposition annealing at 800¢J, the strongest UV emission intensity was obtained in the nitrogen ambient and the strongest visible (green) emission intensity was obtained in the oxygen ambient.

Lung disease affects tens of millions of Americans, making it one of the most common medical conditions in the United States. Many of these lung diseases are classified as chronic airway disease. Because of this, it is important to be able to catch the development early so as to begin treatment as soon as possible to delay the progression and subsequently monitor that progression. One method of doing so is the use of quantitative computed tomography (CT). Study of the airway anatomy can be quantified using such measures as minor inner diameter (MinD), major inner diameter (MajD), wall thickness (WT), inner area (IA), and outer area (OA). Changes in these measures can then be tracked over time to determine how the airways are being affected by disease. The challenge with the desired longitudinal imaging is that prolonged radiation exposure can be dangerous to the patient. In order to make longitudinal imaging more feasible, it is important to determine what quantitative measures can reliably be made at different radiations doses so as to optimize radiation dose and quantitative assessment. Working to make this determination, three different radiation doses were tested to evaluate their quantitative outputs. A high dose (14.98 mGy), medium dose (6.00), and low dose (0.74 mGy) were used to image six different porcine subjects. Images were collected at these doses both while the lungs were in-vivo and once the lungs had been fixed and excised ex-vivo. All of the scans were then processed using APOLLO (VIDA Diagnostics). From the complete airway trees, quantitative measures were collected from thirty-five airways. For the whole lung analysis, the medium and low dose in-vivo scans and the high dose ex-vivo scans were compared to the high dose in-vivo scans to compare assess MinD, MajD, WT, IA, and OA. Then, in order to determine how well the CT measures represent the actual anatomy, a total of thirteen cube samples containing airways were segmented from one of the lungs (based on volume analysis of the lung pre- and post-fixation and visual inspection). The cubes were imaged in CT, for the purpose of aiding in the establishment of original location and studying the effect of a narrowed imaging window, and microscopic CT (μCT). Since μCT can have a resolution on the scale of microns, the values measured in these images were considered ground-truth. The CT and μCT cubes were then registered to the high dose ex-vivo scan so as to compare the cube values with the ex-vivo values from each of the three doses. The same five measures were collected and analyzed. The MinD, MajD, WT, IA, OA were statistically analyzed between the three in-vivo radiation dose scan sets, the high dose in- and ex-vivo scans, and the µCT cube, CT cube, and the three ex-vivo radiation dose sets. Preliminary results for the in-vivo scans show that the low dose and medium dose scans can reliably (< 5% error) be used to evaluate airways with minor diameters between 3.42 mm and 10.34 mm and major diameters between 3.98 mm and 12.06 mm. Comparison of the high-dose in-vivo and ex-vivo scans showed that the fixation and excision of the lungs did not significantly affect the ex-vivo lungs' ability to be used as a model for the in-vivo lungs. Finally, analysis of the various forms of the ex-vivo airways showed that there were few statistically significant differences between the datasets. These results support the use of using the low (0.74 mGy) radiation dose when studying airway disease affecting airways with minor diameters between 3.42 mm and 10.34 mm and major diameters between 3.98 mm and 12.06 mm. They also show that the quantitative measures from CT are representative of the true measures of the airways.

The main objective of the thesis was to gain better understanding of key parameters associated with Cold Work (CW) and their possible effects on Stress Corrosion Cracking (SCC) susceptibility of Austenitic Stainless Steels (ASS) cold rolled to different degrees. The microstructural characterisation of the cold rolled ASS was carried out using optical microscopy to determine and correlate the average grain size with the level of CW. The assessment of martensite development during the CW was carried out using the neutron diffraction technique. The effects of CW levels and strain paths on the lattice strain evolution during the in-situ loading and on the mechanical failure of cold worked ASS were studied. The electrochemical behaviour of cold rolled ASS was also studied. Finally, The SCC susceptibility of ASS was investigated using the Slow Strain Rate Testing (SSRT) techniques. The post-mortem analyses of the failed samples were carried using the optical and Scanning Electron Microscopy (SEM). The study showed that the average grain size decreases with CW and reaches minimum at 20%CW. The smallest and the largest grain size occurred consistently on the Longitudinal (L) and Short-transverse (S) plane respectively. Evidence of martensite development was only found during the plastic deformation at cryogenic temperature and none was observed at ambient temperature. The study showed that the strength of material increases with the level of CW. The Bauschinger effect occurred when the strain path is reversed and its magnitude is independent on whether the tensile or compressive prestraining comes first or last but rather dependent on the amount of CW. The correlation between the CW levels and the lattice strain evolution during the in-situ loading showed that, the lattice strain increases with prestrain and reaches saturation in the material prestrained to 20%CW.The result of the mechanical failure test showed that, 20% cold rolled material loaded along the L and Transverse (T) directions showed a gradual failure, whilst the material loaded along the S direction exhibited a rapid failure. The SEM micrographs suggest that materials loaded along the L and T direction failed with the characteristic features of pure ductile failure while the specimen loaded along S direction showed mixed features of the ductile and brittle failure. The electrochemical properties of the cold rolled materials are more affected by sample orientation than the levels of CW. The short-transverse plane was observed to be most noble whilst the longitudinal plane was the least noble. The results of the SSRT in the chloride environment showed that the plastic elongation, the ultimate tensile strength and the time to failure decrease as the applied potential increases. The post-mortem analysis of the failed samples with the SEM showed that, the fracture surface contained region of ductile failure characterised by dimples, and region of SCC with secondary cracks along the loading axis. Whilst the cross sectional analysis, showed evidence of predominant transgranular stress corrosion cracks. The study found that SCC susceptibility of the ASS is directly linked to strain heterogeneity and directional anisotropy caused by cold working.

No description available.

Cette thèse présente la reconstruction de l’histoire tectono-thermique du massif varisque des Jebilet (Maroc) à fort potentiel minier, depuis son évolution pré-orogénique au Dévonien supérieur-Carbonifère inférieur jusqu’à sa structuration pendant l’orogénèse varisque-alléghanienne au Carbonifère supérieur-Permien inférieur. Pour répondre à cette problématique, ce travail s’organise autour de deux approches : (1) l’une métrologique appliquée à la géothermométrie Raman sur la matière carbonée (RSCM) et (2) l’autre intégrant une étude structurale, géochronologique et une analyse de la thermicité.L’approche métrologique a permis de valider l’applicabilité du géothermomètre RSCM (1) dans un contexte de métamorphisme polyphasé, (2) pour des roches carbonatées et des skarns des Jebilet et (3) de proposer un nouveau paramètre Raman RSA permettant de mieux préciser les températures supérieures à 500°C et d’étendre l’applicabilité de la méthode jusqu’à des températures maximales qui atteignent les 700°C.A partir de l’approche intégrée, trois épisodes tectono-thermiques ont été mis en évidence. Le premier épisode D₀ correspond à une tectonique extensive permettant l’ouverture du bassin des Jebilet au Dévonien supérieur-Carbonifère inférieur. Cette tectonique extensive est accompagnée par une anomalie thermique supérieure à 500°C déduites des mesures de géothermométrie RSCM (TRSCM) et par une importante activité magmatique bimodale et granodioritique datée dans ce travail entre 358 ± 7 et 336 ± 4 Ma. Au Carbonifère supérieur débute la phase compressive structurant le massif des Jebilet avec la mise en place de nappes superficielles au Namuro-Westphalien (D₁), suivie par la phase varisque majeure (D₂). L’analyse structurale a permis de montrer une évolution progressive du régime de déformation de D2 depuis une compression coaxiale à une transpression dextre compatible avec un raccourcissement horizontal WNW-ESE à NW-SE. D₂₁ est associée à deux événements thermiques, le premier syn-tectonique de moyenne température (300°<TRSCM<400°C), et le second syn- à post-tectonique de haute température (600°<TRSCM<660°C).Ce contexte tectono-thermique serait l’expression de processus géodynamiques impliquant à partir du Dévonien supérieur une délamination de la lithosphère rhéïque par « slab break-off » ou « slab roll-back » qui entrainerait (1) la remontée de courant asthénosphérique chaud, et (2) la rotation horaire de Gondwana et son amalgamation progressive avec Laurussia structurant au Carbonifère supérieur-Permien inférieur la chaine varisque-alléghanienne. / This thesis presents the reconstruction of the tectono-thermal history of the Paleozoic Jebilet massif (Morocco), from its pre-orogenic evolution at the Upper Devonian-Lower Carboniferous to its structuration during the variscan-alleghanian orogeny at the Upper Carboniferous-Lower Permian. To address this issue, this work is organized around two approaches: (1) one metrological applied to the Raman Spectroscopy of Carbonaceous Matterial (RSCM) and (2) the other integrating a structural and geochronological study and a thermicity analysis.The metrological approach allowed to validate the applicability of the RSCM geothermometer (1) in a context of polyphase metamorphism, (2) for carbonate rocks and skarns of Jebilet and (3) to propose a new parameter Raman RSA allowing to better specify temperatures above 500°C and extend the applicability of the method to maximum temperatures of up to 700°C.From the integrated approach, three tectono-thermal episodes were highlighted. The first episode D₀, corresponds to an extensive tectonic allowing the opening of the Jebilet basin at the Upper Devonian-Lower Carboniferous. This opening is accompanied by a HT thermal anomaly as shown by the important bimodal and granodioritic magmatic activity dated between 358 ± 7 Ma and 336 ± 4 Ma and the TRSCM higher than 500°C recorded by the rocks. During Upper Carboniferous, the compressive phase structuring the Jebilet massif begins with the emplacement of superficial nappes (D₁), followed by the variscan major phase (D2). Structural analysis showed a gradual evolution of D₂ deformation regime from coaxial compression to dextral transpression consistent with WNW-ESE to NW-SE horizontal shortening. D₂ is associated with two thermal events, the first is syn-tectonic with TRSCM between 300 and 400°C, and the second is syn- to post-tectonic with TRSCM between 600 and 660°C.This tectono-thermal context would be the expression of geodynamic processes involving from the Upper Devonian a delamination of the Rheic lithosphere by "slab break-off" or "slab roll-back" which would induce (1) the rise of hot asthenospheric current, and (2) the clockwise rotation of Gondwana and its gradual amalgamation with Laurussia structuring the variscan-alleghanian belt during the Upper Carboniferous-Lower Permian.

To analyse drill samples in a mine, a scanner that uses a gamma ray detector can be used. The scanner can analyse the drill sample to quickly see the elements present in the sample without destroying it. To improve the performance of the scanner, the electric signal from the detector needs to be less noisy, and different pulse shaping methods, filters and smoothers can be used on the sampled data to achieve an improved performance. In this master thesis, the electric noise model of the electronics around the detector was modeled, and analysed. Different pulse shaping method, filters and smoothers was also tested to see which method gave the best performance in FWHM sense. The Full Width at Half Maximum (FWHM) is the energy resolution of a detector, and is defined as the full width of a photopeak at the half maximum. The noise model of the schematic for the preamplifier was made by hand with support from MATLAB. The resulting noise model was compared between MATLAB and LTspice, and the conclusion is that the JFET is the main contributor of the significant noise, contributing to 98 % of the total noise at 10 GHz. The adopted filters and pulse shaping method are, matched filter, custom filter, CR-RC shaping, mean filter, median filter and clustering. The results from the tests indicated that custom filter with a FWHM of 1.96 keV and CR-RC with a FWHM of 1.67 keV shaping were more accurate than the matched filter with the FWHM of 5.1 keV. But the results also showed that it is important to take into account the waveform variance, due to inherent properties in the detector, with this consideration the FWHM of CR-RC shaper was improved from 2.29 keV to 1.67 keV. The clustering method was the most promising method but due to time constraints this method was never fully tested and no FWHM value was achieved.

This thesis deals with an evaluation of optical components for LED, which is based on laboratory measurements of available LED samples and optical elements. The evaluation is done according to established standards and is focused on efficiency and adjustment of luminous flux (beam angle, luminous curve). Furthermore was made a study engaged in an optical element influence on LED color properties (color temperature, spectral characteristics). In conclusion there is an optical elements usage overview and recommended procedure for selecting appropriate combination of LED and optical element.

The primary purpose of this study was to investigate the combination of experimental and computational methods in the search for reproducible colloidal surface-enhanced Raman scattering of pharmaceutical compounds. In the search for optimal experimental conditions for colloidal surface-enhance Raman scattering, the amphipathic β-blocker propranolol was used as the target molecule. Fractional factorial designs of experiments were performed and a multiobjective evolutionary algorithm was used to find acceptable solutions, from the results, that were Pareto ranked. The multiobjective evolutionary algorithm suggested solutions outside of the fractional factorial design and the experiments were then performed in the laboratory. The results observed from the suggested solutions agreed with the solutions that were found on the Pareto front. One of the experimental conditions observed on the Pareto front was then used to determine the practical limit of detection of propranolol. The experimental conditions that were chosen for the limit of detection took into account reproducibility and enhancement, the two most important parameters for analytical detection using surface-enhanced Raman scattering. The principal conclusion to this study was that the combination of computational and experimental methods can reduce the need for experiments by > 96% and then selecting solutions from the Pareto front improved limit of detection by a factor of 24.5 when it was compared to the previously reported limit of detection for propranolol. Using the same experimental conditions that were used for the limit of detection, these experiments were extended to plasma spiked with propranolol in order to test detection of this pharmaceutical in biofluids. Concentrations of propranolol were prepared using plasma as the solvent and measured for detection using colloidal surface-enhanced Raman scattering. Detection was determined as <130 ng/mL, within physiological concentrations, previously achieved using separation techniques. The second part of this thesis also involved a combination of experimental and computational methods. Raman optical activity was utilized to investigate secondary structure of amino acids and diamino acid peptides in combination with density functional theory calculations. Amino acids are important biological molecules that have vital functions in the biological system. They have been recognized as neurotransmitters and implicated in neurodegenerative diseases. Raman and Raman optical activity experimental results were compared to determine site-specific acetylation, marker bands for constitutional isomers and identification of functional groups that interact with the solvent. The experimental spectra were then compared to those from the density functional theory calculations. The results indicated that; constitutional isomers cannot be distinguished from the Raman spectra but can be distinguished from the Raman optical activity spectra, site-specific acetylation can be identified from the Raman spectra, however, Raman optical activity provides more structural information in relation to acetylation. When the results were compared to the density functional theory calculations for the diamino acid peptides the results agreed reasonably well, however, agreement was not as good for the monoamino acids because diamino acid peptides support fewer conformations due to the peptide bond whereas monoamino acids can adopt a far greater number of conformations. Combined computational and experimental techniques have developed the ability to detect and characterize biomedical compounds, a significant move in the advancement of Raman spectroscopies.