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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analysis of Capillary Forces in Electrowetting and Precision Self Assembly

Ramadoss, Vivek 19 March 2008 (has links)
Developments in micro and nano technology have great potential in many applications. Two applications that will be addressed in this work are self assembly of microdevices and Electrowetting in microfluidics. Capillary forces are the most critical factor in both of these techniques and need proper characterization. This thesis describes a detailed study of these forces and explains how they were utilized as an effective source of drive in high end applications. Self assembly is a promising alternative to conventional pick and place robotic assembly of micro components. Its benefits include parallel integration of parts with low equipment costs. Various approaches to self assembly have been demonstrated, yet demanding applications like assembly of micro-optical devices require increased positioning accuracy. This thesis proposes a new method for design of self assembly bonds that addresses this need. Current methods have zero force at the desired assembly position and low stiffness. The proposed method uses a substrate assembly feature to provide a high accuracy alignment guide to the part. The capillary bond region of the part and substrate are then modified to create a non-zero positioning force to maintain the part in the desired assembly position. Capillary force models show that this force aligns the part to the substrate assembly feature and reduces the sensitivity of part position to process variation. Thus, the new configuration analyzed proves substantial improvement in positioning accuracy of capillary self assembly. Guidelines are proposed for the design of an effective assembly bond using this new approach. Electrowetting is another application that has been successfully demonstrated as a means of drop manipulations in digital micro-fluidic devices. These demonstrations show that electrowetting actuation holds great promise, but there are also reports of erratic behavior and system degradation. While a method for electrowetting force measurement to track the degradation of the electrowetting response was demonstrated, this thesis analyzes some adverse effects in the electrowetting response due to variations during measurement of electrowetting forces, specially the variation of volume, the tilt in the part considered for measurements, and defective layer response.
2

從優選理論分析台灣閩南語的重疊構詞 / An OT Approach to Reduplication in Taiwan Southern Min

許淨涵, Hsu, Ching Han Unknown Date (has links)
本文以優選理論為框架探討閩南語三字組及四字組重疊構詞,三字組及四字組重疊構詞可分成完全重疊與部分重疊,重疊詞要緊鄰其對應詞基越好,此外,對於四字組部分重疊構詞有對整方向不一致的體現,筆者認為不同的制約排序會產生不同的重疊規則,並採用音韻共存理論(Cophonology Theory)來解釋閩南語多元的重疊構詞策略是由多個次語法運作的結果。在三字組重疊構詞,根據句法結構判斷主重音的位置,主重音的分佈影響重疊的規則,但有語意強調某成份時,主重音會轉移且會使原成份之本調喪失變成輕聲,有主重音的音節才可進行重疊構詞,同時,重疊詞要越緊鄰其對應詞基。在四字組完全重疊構詞,語義的強調與弱化影響詞基音節以及音步的重疊運作,音節與音步制約層級不同可解釋不同的重疊規則;在四字組部分重疊構詞,不同於過去研究以單一方向對整制約論證,筆者提出雙向的對整制約來解釋四字組部分重疊構詞。簡言之,本篇論文藉由優選理論的觀點,首度就閩南語重疊構詞提出一個整體分析。 / This thesis examines the derivation of the reduplication in Taiwan Southern Min under the framework of Optimality Theory. Reduplication can be divided into two categories. One is trisyllabic reduplication and the other is quadrisyllabic reduplication. Besides, each type of the trisyllabic and quadrisyllabic reduplication has both partial and full reduplication. This thesis adopts Cophonology Theory to account for the subgrammar of the divergent reduplications. Based on Locality Generalization, the reduplicant should be adjacent to its corresponding base. In trisyllabic reduplication, from the perspective of syntactic relation, stress affects the derivation of the reduplication. The primary stressed syllable is the only syllable which can be reduplicated. This thesis proposes constraint *RED(W) to require this condition. In quadrisyllabic reduplication, given the base is disyllable AB, semantic weakness and stress closely relate to the full reduplication AABB and ABAB. The different ranking of the Adjacency-BR-by-syllable and Adjacency-BR-by-foot explains the full reduplication. In quadrisyllabic partial reduplication, this thesis proposes the different edges alignment constraint Align(RED, R; Rightmost Monosyllabic Morpheme, L) and Align(RED, L; Leftmost Monosyllabic Morpheme, R) to explain ABAC and ACBC, respectively. In summary, based on the constraint-based theory, and the interaction of Nonhead stress, Focal stress, *RED(W), alignment, anchoring, adjacency, and contiguity constraint, this thesis has given a general explanation of the reduplication in Taiwan Southern Min.

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