No description available.

No description available.

The Santa Barbara Instrument Group self-guided spectrograph is aimed primarily at the advanced amateur astronomer. This study has determined that this instrument is capable of being used for scientific research. A comparison lamp box was built to be used in conjunction with the spectrograph. A test was conducted to determine the accuracy of the grating positioning micrometer. A chart was created to allow the conversion of the micrometer readings to correlate with the position of the low-dispersion grating. To determine the scientific applicability of the spectrograph, it was used to: (1) measure the expansion rate of Nova Sagittarius 2004, (2) look for a 13.9-minute periodicity in the width and position of the H-alpha line of the binary star system X Persei, and (3) to measure the Doppler shift of X Persei. The instrument proved to be capable of being used to determine radial velocities and Doppler shifts. / Department of Physics and Astronomy

There is no abstract available for this thesis. / Department of Physics and Astronomy

Amino acids are the basic building blocks of proteins. The determinationof their structures plays an important role in correctly describing the functionsof the proteins. This thesis is devoted to theoretical studies on the potentialenergy surface of amino acids, in particular the infrared and soft X-ray spectralfingerprints of their most stable conformers.The stable structures of amino acids can be explored by different methods.We have used a full space systematic search strategy to determine the potentialenergy surface of deprotonated arginine and revealed several new conformers.With that, the calculated thermodynamic parameters are finally in good agreementwith their experimental counterparts. We have also proposed a molecularfragment based step-by-step strategy to search for the most stable conformers oflarge biomolecules. The high efficiency and good accuracy of this strategy havebeen firmly illustrated by the modeling of several polypeptides.Infrared (IR) spectroscopy has become one of the most applied techniques tocharacterize the structures of gas-phase amino acids. A direct comparison betweenexperimental and calculated infrared spectra provides an efficient way to describethe conformation exchanges of the amino acids. It is found that the conformersof an amino acid are not always necessary to reach the thermal equilibrium undercertain experimental conditions. The local minima could be responsible for theappearance of the measured spectra. This important point has been highlightedby the calculations of deprotonated tyrosine and cysteine, as well as the arginine.The near-edge X-ray absorption fine structure (NEXAFS) spectra and X-rayphotoelectron spectra (XPS) have also been simulated for neutral, deprotonatedand protonated arginine. The influences of intra-, and intermolecular hydrogenbonds on the electronic structure of the arginine have been carefully examined. Itis suggested that the XPS is capable of distinguishing the canonical and zwitterinicisomers of arginine, and works much better than any other tools available. / <p>QC 20140522</p>

This research work focused on studying the emission spectroscopy produced from the high energy ion-molecule collision processes in mass spectrometry. The collision experiments are described and divided into 4 chapters (Chapter 3, 4, 5, 6).N2O+● is an ion of atmospheric importance. In chapter 3 the investigation of the collision between high translational energy (4-8 keV range) N2O+● ions and Helium target gas in mass spectrometry using collision induced emission (CIE) spectroscopy is described.In chapter 4, the collision-induced emission (CIE) spectra from 4-8 keV collisions between projectile He+● ions and CO2 target gas (He+●/CO2) were obtained. In Chapter 5, to probe the validity of this hypothesis, CIE experiments were carried out to observe the photon emissions from keV collisions of a selection of projectile ions with O2 target gas. By studying the resulting CIE spectra, a second potential mechanism came to light, one that involves the nearly isoenergetic O2+. A → X state transition. In chapter 6, neutral hydroxymethylene and formaldehyde were generated by charge exchange neutralization of their respective ionic counterparts and then were reionized and detected as recovery signals in neutralization-reionization mass spectrometry in the modified VG-ZAB mass spectrometer.

Improvements to radiation therapy treatment outcomes rely, in part, on consideration of patient specific radiosensitivity. Therefore an assay which quantifies radiation-induced biochemical changes, and subsequently characterizes radiation responses in tumour and normal tissue is required. This work investigates the use of a single cell Raman spectroscopic technique to identify radiation-induced responses in human lung (H460), breast (MCF-7, MDA-MB-231) and prostate (LNCaP) cancer cell lines each selected to create a panel of cells varying in tissue of origin and radiation sensitivity. Cells were cultured in vitro and exposed to clinically relevant (< 10 Gy) doses of radiation. Cell populations receiving 30 and 50 Gy were also studied in order to further elucidate dose-dependent trends and give additional information about the ability of Raman spectroscopy to identify radiation-induced biochemical changes occurring in the cell populations. It was found that using Raman spectroscopy to identify a radiation-induced response in human cells cultured in vitro is governed by the subtlety of the radiation-induced response inherent to a specific cell line. Also the type of biochemical changes occurring in response to exposure to radiation will be dependent on the specific cell line. This work suggests that effective use of single cell Raman spectroscopy to monitor a patient's response to radiation early on in treatment (where the disease has been exposed to 10 Gy or less) is possible. However, a detailed knowledge of the biochemical changes associated with the unique radiation response for that particular disease is required. / Graduate / 0541 / 0752 / 0992 / hardersj@uvic.ca

No description available.

Impedance spectroscopy (IS) was used to evaluate the microstructural changes of a thermally-grown oxide (TGO) layer on a nickel-based superalloy or bond coat, with or without a thermal barrier coating (TBC) system, at various temperatures. TBC is used for hot section parts of gas turbine engine, such as turbine blades and vanes. However, spallation of TBC can take place due to long-term operation at high temperature. The spallation is mainly caused by both microstructural changes and thermal stresses as a result of oxide layer (mainly alumina) formation and growth at the interface between the TBC and bond coat. The electrical resistance and capacitance of the oxide layer, formed from oxidation of IN738LC superalloy at high temperature, were obtained from fitting the results of the measured impedance diagrams based on an equivalent circuit model. The equivalent circuit model should represent the features of the oxide layer or the TBC system. The electrical resistance of the oxide layer increased with increasing oxidation time for samples exposed to air at 900°C. Similar results were obtained for the NiCrCoAIY bond coat samples and the TBC systems. The capacitance decreased with increasing thickness of the alumina layer. The activation energy of electrical conduction was used to characterise the alumina layer formed on the bond coat at 900°C, 1000°C and 1100°C. The activation energy values for the alumina layer, formed at various temperatures, decrease with increasing impurity or porosity. Changes in the electrical properties of TGOs are correlated with those in their microstructure and microchemistry. The degradation of a TBC can be identified, when the electrical resistance of the TGO decreases with increasing oxidation time. The fast decrease in resistivity corresponds to the compositional change in the TGO from cc-Al2O3 to a mixture of a-Cr2O3 and (Ni or Co)(Cr or Al)2O4 spinel. The disappearance of a-A1203 in the TGO makes the scale non-protective and leads to cracks and spallation of TBCs. Non-destructive testing of the crack formation in a TBC system is essential for predicting the failure and lifetime of TBCs in service. IS was used to evaluate the crack formation in the TBC system due to thermal cycling. During the thermal cycling, cracks initiated and propagated along the interface between the TGO and the yttrium stabilised zirconia (YSZ), used as a TBC. This caused the spallation of the TBC eventually. The propagation of cracks at the interface of TGO/YSZ was found to contribute to an increase in the interfacial impedance. The interfacial area determines the interfacial resistance corresponding to the oxygen reaction. Therefore, the crack propagation induced an increase of the interfacial resistance, whereas the interfacial capacitance showed no trend in its alteration with the propagation of the cracks. As a result, the relaxation frequency of the interface moved towards a lower frequency during the propagation of the cracks. Therefore, impedance spectroscopy has been used to examine the crack formation in TBC system non-destructively. By using scanning electron microscopy and X-ray diffraction techniques, the composition and microstructure of the oxide scales were examined. It was found that their electrical properties were determined, not only by the microstructure of the oxide scales, but also by the composition of the oxide scales. By determining the relationship between the electrical properties, microstructure and composition of the oxide scales, IS could be used as a non-destructive technique for monitoring the oxidation of metallic alloys at high temperature in gas turbine engine components.

This thesis is primarily concerned with far infrared effects in semiconductor heterostructures. These properties have been studied as a function of magnetic fields at low temperature using various optical detection techniques. Cyclotron resonance has been studied in CdTe quantum wells. The results are compared with calculations using the memory function approach, which demonstrate that there is a large reduction in the resonant coupling due to level occupancy effects. Semimetallic GaSb/InAs superlattices have been studied by cyclotron resonance experiments. In samples with low InAs/GaSb ratios (~1), a pinning between the heavy hole subbands is predicted by theory which results in a suppression of heavy hole resonance at high magnetic fields. Photoluminescence measurements on a series of ultra-high mobility GaAs/AlGaAs heterojunctions have been performed. It has been found that the modulation caused by far infrared beam is entirely dependent on the filling factors, which is understood as the Landau level coupling effects between the subbands of 2DES. A GaAs/AlGaAs coupled quantum well photodiode has been studied by photoluminescence and photocurrent under the influence of far infrared beam. An enhancement of the photocurrent in the device is observed when the infrared photons are resonant with the intersubband transition between the anti-crossing electronic subbands of the coupled quantum wells, which makes the structure a potential tuneable far infrared detector. Most of the experimental works have been modelled with a k.p theory using momentum matrix approach. The self-consistency incorporated in this model proves to be useful while dealing with semimetallic or nonintrinsic systems. These calculations offer invaluable clues to the semiconductor heterostructures investigated.