Bose-Einstein condensates (BECs) have proven to be remarkable systems with which to study some of the foundational models of condensed matter physics. The observation of a critical velocity for the breakdown of superfluidity in a BEC and the superfluid to Mott insulator transition observed in a BEC trapped by an optical lattice are but two examples of the, by now, dozens of exciting results in this field, which combines theoretical tools from condensed matter physics with state-of-the-art experimental techniques from ultra-cold atomic physics. However, any real condensed matter system has to contend with the effects of disorder, a phenomena notably absent in the inherently clean BEC systems. We have developed and implemented a way to add well characterized disorder in a controlled way to the otherwise clean BEC system using the light field from a laser speckle pattern. Using this system, we have investigated the effects of disorder or a single Gaussian defect, on the collective dipole motion of a BEC of 7Li in an optical trap. In addition, we perform transport experiments on a weakly interacting BEC expanding in a disordered one-dimensional atom wave-guide. We have observed that in such a system, the wave nature of matter can lead to spectacular and counterintuitive phenomena. Specifically, we verify that this system exhibits Anderson localization, a phenomena fundamentally resulting from the interference of multiply scattered matter waves. In such a state, the localized gas behaves as an insulator in a regime where it is classically expected to be conducting. We also present results of experiments regarding a repulsive BEC scattering from a semi-permeable, single defect potential. We investigate the transport properties of such a system with special emphasis on the velocity and defect strength dependent dissipation of the collective dipole motion of the BEC. Finally, we present the results of our experiments on the scattering properties of bright matter wave solitons. We have observed fragmentation of the soliton in a disordered potential as well as both splitting and recombination of a soliton after interacting with a single repulsive defect potential.

We have used the narrow 2 S 1/2 [arrow right] 3 P 3/2 transition in the ultraviolet (UV) to laser cool and magneto-optically trap (MOT) 6 Li atoms. Laser cooling of lithium atoms is usually performed on the 2 S 1/2 [arrow right] 2 P 3/2 (D2) transition, where temperatures of twice the Doppler limit, or ∼300 μ K for lithium, are achieved. The linewidth of the UV transition is seven times narrower than the D2 line, resulting in a lower Doppler limit. We show that a MOT operating on the UV transition reaches temperatures as low as 59 μ K. We load 6 million atoms from this UV MOT into a 1070 nm optical dipole trap (ODT). We show that the light shift of the UV transition in the ODT is small and blue-shifted, facilitating efficient loading. Evaporative cooling of a two spin-state mixture of 6 Li in the ODT produces a quantum degenerate Fermi gas with 3 million atoms in only 11 seconds.

Single crystalline silicon spheres have been used as alternative material for solar cell fabrication. This innovative technology has several advantages over traditional wafer technology. However, the material, process flow and characterization techniques are very different from the planar technology due to the spherical geometry. In material characterization, microwave photoconductivity decay is used to measure carrier lifetime. This technique is analyzed theoretically by mathematical treatment in this thesis. Furthermore, the carrier lifetime is measured in order to investigate rapid thermal grown oxide quality in the role of surface passivation of silicon sphere. A traditional way of making spherical cells is to create a p-n junction by high temperature diffusion of phosphorous dopants into p-type silicon spheres. To further reduce the fabrication cost, a low temperature epitaxial film highly doped with phosphorous is deposited on the sphere surface to form an emitter layer using Plasma Enhanced Chemical Vapour Deposition (PECVD). The process flow of device fabrication is very different from silicon wafer thus a new set of process steps are derived for silicon spheres. Two main device structures, omission of insulating layer and silicon nitride as insulating layer between emitter film and substrate, are proposed. The deposition parameters, pressure, power, and deposition time are optimized for spherical geometry. The quality of the junction is evaluated by its current-voltage characteristic and capacitance-voltage characteristic. The results are also compared to similar device structures in planar technology. To examine the photovoltaic performance, illuminated current-voltage measurement is taken to provide information on short circuit current, open circuit voltage and fill factor. Furthermore, spectral response of quantum efficiency is investigated to assess the ability of carrier collection for a spectrum of wavelength. Limitations on spherical diode performance are concluded from the measurement results.

Dry bean (Phaseolus vulgaris) is a sub-tropical crop severely affected by exposure to low temperatures during all of its growing stages. Cool spring temperatures and the risk of frost are major limiting factors for the early sowing of dry bean in Saskatchewan. Due to its economic importance; however, it has been introduced to Saskatchewan, but it needs to be made more cold tolerant to further expand acreage. The genes that can contribute some tolerance to low temperature stress in bean are not found within the primary gene pool, which limits the capability of breeders to generate a cultivar with such characteristics. Consequently studies have being done in order to find a possible source of genes that can induce tolerance to low temperature exposure. Phaseolus acutifolius is a relative of the domesticated dry bean and previous hybridizations with it have been successful. It is also known to be tolerant to abiotic stresses such as drought. For this reason the decision was taken to explore the level of resistance to low temperature stress exposure in several P. acutifolius accessions. Using whole plant freezing tests in controlled environment chambers, P. acutifolius W6 15578 was found to be more tolerant to exposure to sub-zero temperatures than were P. vulgaris genotypes. Interspecies hybrids were produced between P. vulgaris NY5-161 and W6 15578 and BC2 plants were produced using embryo rescue. The whole plant freezing test is a destructive method that cannot be used with unique F1 and BC2 genotypes, so an alternative methodology to evaluate the hybrids was explored. An electrolyte leakage test was used and showed similar results to the whole plant freezing test with the parent plant controls. The F1 hybrids had an intermediate tolerance to low temperature stress and the further generations (BC1 and BC2) had a better level of tolerance to this kind of stress than the cultivated parent (NY5-161). This suggests that the genes that confer tolerance to low temperature exposure are being maintained through several generations of backcrossing and that these interspecies hybrids may offer a chance for the development of improved dry bean cultivars for the Saskatchewan environment.

Operation of SiGe BiCMOS Technology Under Extreme Environments Tianbing Chen 96 pages Directed by Dr. John D. Cressler "Extreme environment electronics" represents an important niche market and spans the operation of electronic components in surroundings lying outside the domain of conventional commercial, or even military specifications. Such extreme environments would include, for instance, operation to very low temperatures (e.g., to 77 K or even 4.2 K), operation to very high temperatures (e.g., to 200 C or even 300 C), and operation in a radiation-rich environment (e.g., space). The suitability of SiGe BiCMOS technology for extreme environment electronics applications is assessed in this work. The suitability of SiGe HBTs for use in high-temperature electronics applications is first investigated. SiGe HBTs are shown to exhibit sufficient current gain, frequency response, breakdown voltage, achieve acceptable device reliability, and improved low-frequency noise, at temperatures as high as 200-300 C. A comprehensive investigation of substrate bias effects on device performance, thermal properties, and reliability of vertical SiGe HBTs fabricated on CMOS-compatible, thin-film SOI, is presented. The impact of 63 MeV protons on these vertical SiGe HBTs fabricated on a CMOS-compatible SOI is then investigated. Proton irradiation creates G/R trap centers in SOI SiGe HBTs, creating positive charge at the buried oxide interface, effectively delaying the onset of the Kirk effect at high current density, which increases the frequency response of SOI SiGe HBTs following radiation. The thermodynamic stability of device-relevant epitaxial SiGe strained layers under proton irradiation is also investigated using x-ray diffraction techniques. Irradiation with 63 MeV protons is found to introduce no significant microdefects into the SiGe thin films, regardless of the starting stability condition of the SiGe film, and thus does not appear to be an issue for the use of SiGe HBT technology in emerging space systems. CMOS device reliability for emerging cryogenic space electronics applications is also assessed. CMOS device performance improves with cooling, however, CMOS device reliability becomes worse at decreased temperatures due to aggravated hot-carrier effects. The device lifetime is found to be a strong function of gate length, suggesting that design tradeoffs are inevitable.

Low temperature combustion (LTC) is an appealing new method of combustion that promises low nitric oxides and soot emissions while maintaining or improving on engine performance. The three main points of this study were to develop and validate an engine model in GT-Power capable of implementing LTC, to study parametrically exhaust gas recirculation (EGR) and injection timing effects on performance and emissions, and to investigate methods to decrease pressure rise rates during LTC operation. The model was validated at nine different operating points, 3 speeds and 3 loads, while the parametric studies were conducted on 6 of the 9 operating points, 3 speeds and 2 loads. The model consists of sections that include: cylinders, ports, intake and exhaust manifolds, EGR system, and turbocharger. For this model, GT-Power calculates the combustion using a multi-zone, quasi-dimensional model and a knock-induced combustion model. The main difference between them is that the multi-zone model is directly injected while the knock model is port injected. A variety of sub models calculate the fluid flow and heat transfer. A parametric study varying the EGR and the injection timing to determine the optimal combination was conducted using the multi-zone model while a parametric study that just varies EGR is carried out using the knock model. The first parametric study showed that the optimal EGR and injection timing combination for the low loads occurred at high levels of EGR (60 percent) and advanced injection timings (30 to 40 crank angle degrees before top dead center). The optimal EGR and injection timing combination for the high loads occurred at low levels of EGR (30 percent to 40 percent) and retarded injection timings (7.5 to 5 crank angle degrees before top dead center). The knock model determined that the ideal EGR ratio for homogeneous charge compression ignition (HCCI) operation varied from 30 percent to 45 percent, depending on the operating condition. Three methods were investigated as possible ways to reduce pressure rise rates during LTC operation. The only feasible method was the multiple injection strategy which provided dramatically reduced pressure rise rates across all EGR levels and injection timings.

As global focus shifts towards the health and conservation of the planet, greater importance is placed upon the hazardous emissions of our fossil fuels, as well as their finite supply. These two areas remain intense topics of research in order to reduce green house gas emissions and increase the fuel efficiency of our vehicles. A particular solution to this problem is the diesel engine, with its inherently fuel-lean combustion, which gives rise to low CO2 production and higher efficiencies than its gasoline counterpart. Diesel engines, however, typically exhibit higher nitrogen oxides (NOx [NOx = NO NO2, where NO is nitric oxide and NO2 is nitrogen dioxide]) and soot. There exists the possibility to simultaneously reduce both emissions with the application of low temperature diesel combustion (LTC). While exhibiting great characteristics in simultaneous reductions in nitrogen oxides and soot, LTC faces challenges with higher carbon monoxide (CO) and hydrocarbon (HC) emissions, as well as penalties in fuel efficiency. The following study examines the characteristics of LTC which contribute to the differences in emissions and efficiency compared to typical conventional diesel combustion. More specifically, key engine parameters which are used to enable LTC, such as EGR and fuel pressure are swept through a full range to determine their effects on each combustion regime. Analysis will focus on comparing both combustion regimes to determine how exhaust gas recirculation (EGR) and fuel pressure relate to lowering NO and smoke concentrations, and how these relate to a penalty in fuel efficiency. This study finds that the application of LTC is able to realize a 99 percent reduction in NO while simultaneously reducing smoke by 17 percent compared to the conventional combustion counterpart. Through a sweep increasing EGR, LTC is able to defeat the typical soot – NO tradeoff; however, brake fuel conversion efficiency decreases 6.8 percent for LTC, while conventional combustion realizes a 4 percent increase in efficiency. The sweep of increasing fuel pressure confirms typical increases in NO and decreases in smoke for both LTC and conventional combustion; however, brake fuel conversion efficiency increases 2.3 percent for LTC and drops 4 percent for conventional combustion.

In this thesis, a home made chirp-controlled pump-probe measurement system has been developed and is used to explain possible mechanism of THz radiation enhancement under positive chirped incident pulse. The chirp-controlled pump-probe measurement system with temporal resolution of around 100 femtosecond and chirp parameter tuning from ¡V350 fs2 to +650 fs2 is demonstrated. Meanwhile, using chirp-controlled pump-probe measurement system, ultrafast dynamics of photogenerated carrier in low-temperature growth GaAs in different chirp by is characterized. The relaxation time of low-temperature growth GaAs in positive chirp pump pulse is 461fs and shorter than one, which is 497fs, in negative chirp pump pulse. The result is explained by the Pump-Dump process in negative chirp pump pulse and similar band-filling effect in positive chirp pump pulse.

This thesis proposes an analytical method to synthesize bandpass filter with multiple transmission zeros. By using the six pre-determined parameters including two reflection zeros, two matching quality factors, and two transmission zeros, the method can exactly synthesize the corresponding prototype of second-order coupled-resonator bandpass filter. The synthesized filters not only can provide two pre-determined transmission zeros in the lower and upper side of the passband, but also can generate an extra transmission zero in the stopband. This thesis presents the prototypes of the bandpass filter and the methods of synthesis in detail. Finally this thesis implements compact LTCC bandpass filters by using the proposed synthesis method for 3.5 GHz WiMAX applications.

A new modified-T equivalent-circuit model for the embedded inductors in LTCC is first introduced in this thesis. The model can predict the parallel, series, and ground resonant frequencies successfully. For the embedded capacitors in LTCC, a £k-equivalent circuit that can include first two resonant frequencies has been used. One example for each model has been established to illustrate the broadband features of the models. Finally, a parameter table is given to evaluate the performance of these embedded LTCC inductors and capacitors.