Thesis (M.S.)--University of Florida, 2001. / Title from first page of PDF file. Document formatted into pages; contains vii, 45 p.; also contains graphics. Vita. Includes bibliographical references (p. 43-44).

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

No description available.

A number of recently constructed bridge approach slabs using an articulation at mid span and the wide flange terminal anchorage system have experienced settlement at their expansion joints. This problem is more commonly referred to as the bump at the end of the bridge. This study investigated reasons for the bumps and recommended ways to improve the current situation. To find out possible causes of the bridge approach slab problem, literature review, questionnaire survey, and a visual inspection for 18 Houston sites were conducted. Based on the results, two bridge sites in Houston, Texas, were selected for detailed investigation. An extensive series of laboratory and field tests were performed at each site. The main causes of bump at two study sites were compression of embankment soil and natural soil, and poor compaction of embankment soil. The finite-element computer program ABAQUS was used to evaluate behavior of the current approach slab design and of a possibly more effective design. The results show that the transition zone is about 12 m with 80 percent of the maximum settlement

This dissertation presents a serial study on optical properties of different semiconductor materials. Three main types of studies are addressed: The role of doping levels of N and Al atoms in the room-temperature photoluminescence (PL) of 4H-SiC films for optoelectronic applications; the use of a basic Monte Carlo method combined with probability calculations of the time-dependent Schroedinger equation to manifest multi-photon absorption and emission of II-VI compound quantum dots (QDs) for bioimaging; a theoretical quantum chemistry approach to study of structure and optical properties of InGaAsN and GaAs clusters for laser technology applications. 4H-SiC films were grown on AlN/SiC(100) substrates by a chemical vapour deposition (CVD) system. Three well-defined room-temperature PL peaks close to the band-gap energy were observed. By a detailed theoretical analysis of optical transitions in the samples, it was found that the PL peaks are most probably due to the optical transitions between impurity levels and band edges, and the transition between the second minimum of the conduction band and the top of the valance band. Special attention has been paid to effects of doping levels of N and Al impurities. Optical transitions in several II-VI semiconductor QDs have been studied by a quantum Monte Carlo method. We model the QD energy band structure by a spherical square quantum well and the electrons in the conduction band and holes in the valence band by the effective mass approximation. The optical probabilities of optical transitions induced by ultrafast and ultraintense laser pulses are calculated from the time-dependent Schroedinger equation. With the inclusion of the nonradiative electron-phonon processes, the calculated absorption and emission spectra are in agreement with experimental work. The dynamic processes and up-conversion luminescence of the QDs, required for many applications including bio-imaging, are demonstrated. Quantum chemistry is used to study InGaAsN and GaAs nano systems. The molecular structures of a series of dilute-nitride zinc blende InGaNAs clusters are examined from the energy point of view with a semi-empirical method. The optimum cluster configurations are identified by which we can identify the detailed bonding structures and the effects of In mole fraction. After proper geometry construction, an effective central insertion scheme has been implemented to study the electronic band structures of GaAs at the first-principles level. The formation of energy bands and quantum confinement effects have been revealed, thus providing theoretical support for laser design. / QC 20100730

Nine experiments were conducted to explore pitch-time integration in music. In Experiments 1-6, listeners heard a musical context followed by probe events that varied in pitch class and temporal position. When evaluating the goodness-of-fit of the probe (Experiment 1), listeners’ ratings showed more influence of pitch class than of temporal position. The tonal and metric hierarchies contributed additively to ratings. Listeners again rated goodness-of-fit in Experiment 2, but with instructions to ignore pitch. Temporal position dominated ratings, but an effect of pitch consistent with the tonal hierarchy remained. Again, these two factors contributed additively. A speeded classification task in Experiments 3 and 4 revealed asymmetric interference. When making a temporal judgment (Experiment 3), listeners exhibited a response bias consistent with the tonal hierarchy, but the metric hierarchy did not affect their pitch judgments (Experiment 4). Experiments 5 and 6 ruled out alternative explanations based on the presence of pitch classes and temporal positions in the context, unequal numbers of pitch classes and temporal positions in the probe events, and differential difficulty of pitch versus temporal classification. Experiments 7-9 examined the factors that modulate the effect of temporal variation on pitch judgments. In Experiment 7, a standard tone was followed by a tonal context and then a comparison tone. Participants judged whether the comparison tone was in the key of the context or whether it was higher or lower than the standard tone. For both tasks, the comparison tone occurred early, on time, or late with respect to temporal expectancies established by the context. Temporal variation did not affect accuracy in either task. Experiment 8 used the pitch height comparison task, and had either a tonal or an atonal context. Temporal variation affected accuracy only for atonal contexts. Experiment 9 replicated these results and controlled for potential confounds. The findings imply that the tonal contexts found in typical Western music bias attention toward pitch, increasing the salience of this dimension at the expense of time. Pitch salience likely arises from long-term exposure to the statistical properties of Western music and is not linked to the relative discriminability of pitch and time.

Nine experiments were conducted to explore pitch-time integration in music. In Experiments 1-6, listeners heard a musical context followed by probe events that varied in pitch class and temporal position. When evaluating the goodness-of-fit of the probe (Experiment 1), listeners’ ratings showed more influence of pitch class than of temporal position. The tonal and metric hierarchies contributed additively to ratings. Listeners again rated goodness-of-fit in Experiment 2, but with instructions to ignore pitch. Temporal position dominated ratings, but an effect of pitch consistent with the tonal hierarchy remained. Again, these two factors contributed additively. A speeded classification task in Experiments 3 and 4 revealed asymmetric interference. When making a temporal judgment (Experiment 3), listeners exhibited a response bias consistent with the tonal hierarchy, but the metric hierarchy did not affect their pitch judgments (Experiment 4). Experiments 5 and 6 ruled out alternative explanations based on the presence of pitch classes and temporal positions in the context, unequal numbers of pitch classes and temporal positions in the probe events, and differential difficulty of pitch versus temporal classification. Experiments 7-9 examined the factors that modulate the effect of temporal variation on pitch judgments. In Experiment 7, a standard tone was followed by a tonal context and then a comparison tone. Participants judged whether the comparison tone was in the key of the context or whether it was higher or lower than the standard tone. For both tasks, the comparison tone occurred early, on time, or late with respect to temporal expectancies established by the context. Temporal variation did not affect accuracy in either task. Experiment 8 used the pitch height comparison task, and had either a tonal or an atonal context. Temporal variation affected accuracy only for atonal contexts. Experiment 9 replicated these results and controlled for potential confounds. The findings imply that the tonal contexts found in typical Western music bias attention toward pitch, increasing the salience of this dimension at the expense of time. Pitch salience likely arises from long-term exposure to the statistical properties of Western music and is not linked to the relative discriminability of pitch and time.

In this thesis, the root-locus theory for a class of diffusion systems is studied. The input and output boundary operators are co-located in the sense that their highest order derivatives occur at the same endpoint. It is shown that infinitely many root-locus branches lie on the negative real axis and the remaining finitely many root-locus branches lie inside a fixed closed contour. It is also shown that all closed-loop poles vary continuously as the feedback gain varies from zero to infinity.

In this thesis, the root-locus theory for a class of diffusion systems is studied. The input and output boundary operators are co-located in the sense that their highest order derivatives occur at the same endpoint. It is shown that infinitely many root-locus branches lie on the negative real axis and the remaining finitely many root-locus branches lie inside a fixed closed contour. It is also shown that all closed-loop poles vary continuously as the feedback gain varies from zero to infinity.