The design and implementation of a small-scale solar energy conversion system is presented in this thesis. The power circuit of the PV inverter is composed of a push-pull converter and a full-bridge inverter. The inverter converts DC power generated by photovoltaic cells into AC power. This design allows flexible arrangements of various solar cells modules. The systems can supply loads and feed excess power to the grid with unit power factor when operated under grid-connected mode, or supply loads exclusively by operating in the stand-alone mode. In grid-connected mode, it is controlled to follow the variations of solar panel insolation for achieving maximum power point tracking. A 150W prototype of the conversion system is implemented, simulation and experimental results are provided to verify the performance.

The aim of this study is to understand students¡¦ solutions (to problems related to time, time interval, and time unit conversion) and to analyze their common errors and possible causes. Students¡¦ problem-solving strategies and error types were also categorized and used as a reference for improvement in teaching and a scaffold for supporting students' learning. Findings in this research were three: 1. Distinction between time and interval. Students were performing better in the concept of interval than in the concept of time. They also performed well in total time consumed and in daily life problems such as clock time. However, problems with longer text description would make it harder for students to do problem solving in the concept of time and interval. 2. Problem-solving types. The problem-solving types ranked by the frequency are: (1) processing larger units first; (2) converting time from high scale to low scale and vice-versa; (3) using fractions; (4) using decimals; and (5) using addition. 3. Error types: The error types presented by students in solving time-related problems include: (1) interference of the decimal; (2) interference between non-decimal time conversion systems; (3) insufficient knowledge about division; (4) unclear concept about high and low scales of time; (5) incorrect calculation; (6) influence of the clock dial structure; (7) incorrect problem-solving strategy; (8) misjudgment of keywords; and (9) ignorance of problem conditions.

Ultra Wide Band (UWB) is a short-pulse electrical signal, which is widely used for short distant wireless communication due to its low path loss, good immunity to multipath propagation, and high data rate. The main target transmission area of UWB is within 10 meters. Using optical fiber as carrier can bust up the communication capacitance in long distance range because of high capacitance, low loss propagation, and TDM and WDM compatible properties of fiber. Thereby, the technique of UWB on fiber has become more and more important. In this work, a novel method using waveguide photodetector (WP) with short termination for interface of optical fiber and wireless is proposed and demonstrated. The structure is simple without employing any complicated frequency mixer, intermediate frequency, or complex systems. This work is divided into two parts: (1) generation of UWB electrical signals and (2) wavelength conversion of UWB through WP. In the former, a WP with short termination is used in the device. The photocurrent excited by short optical pulse is distributive generated through the waveguide, forming two opposite directions of electrical waves. By reflection on the short termination, the reversed phase of one electrical wave is added to another electrical wave through a delay line, forming a monocycle of UWB signal. By appropriate design on the length of waveguide, the band of 2-10GH is demonstrated, fitting the requirement of FCC (Federal Communications Commission). In the second part of this paper is the wavelength conversion of UWB. The active region of WG is multiple quantum wells (M.Q.W.), which is not only served as photo-absorption layer, but also can be used the electroabsorption material. By pumping M.Q.W.s with high optical power, the cross absorption properties can be applied for wavelength conversion. By pumping power of 12dBm, the wavelength-converted UWB signal is successfully demonstrated at range of 1545nm-1570nm. Using this method, the application of UWB on router of fiber optical network is expectable.

In this study, we implement an emotional text-to-speech system for the limited domain of on-line play-by-play baseball game summary. TheChinese Professional Baseball League (CPBL) is our target domain. Our goal is that the output synthesized speech is fluent with appropriate emotion. The system first parses the input text and keeps the on-court informations, e.g., the number of runners and which base is occupied, the number of outs, the score of each team, the batter's performance in game. And the system adds additional sentences in the input text. Then, the system outputs neutral synthesized speech from the text with additional sentences inserted, and subsequently converts it to emotional speech. Our approach to speech conversion is to simulate a baseball braodcaster. Specifically, our system learns and uses the prosody from a broadcaster. To learn the prosody, we record two baseball games and analyze the prosodic features of emotional utterances. These observations are used to generate some prosodic rules of emotional conversion. The subjective evaluation is used to study the preference of the subjects about the additional sentences insertion and the emotion conversion in the system.

The main purpose of this research is to design a thermal energy conversion device, which is aimed to collect unused heat produced by nature. In order to achieve high-efficiency conversion, some novel devices will be studied to convert heat energy into mechanical power. A simple heat exchanger as well as heat engine device is proposed in this study. Dichloromethane is used as an important factor due to its physical properties. Finally, the concept of a tubular linear generator will be adopted to generate electric power. The feature of the proposed simple thermal energy conversion device is that we can use unused heat sources as input, such as solar energy and waste heat from car engines. Besides, the system is capable to work under the condition of low-temperature difference

Thèse doctorat : Chimie Organique Moléculaire et Chimie des Matériaux : Strasbourg 1 : 2006. / Titre provenant de l'écran-titre. Bibliogr. 5 p.

Thesis (M.A.)--University of Delaware, 2009. / Principal faculty advisor: David M. Stone, Dept. of Art History. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 202-210).

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 63-65). Also available on the Internet.

Thesis (D. Miss.)--Western Seminary, Portland, OR, 2000. / Abstract. Includes bibliographical references (leaves 262-267).