Based on the convenience of the use, the traditional display will be replace by the flexible display. According to this reason, it is very important to study on the reliability of the amorphous silicon (a-Si:H) thin-film transistor (TFT) used in LCD under different mechanical strain. In this research, besides of the above-mentioned we also applied AC stress, to understand the influence of AC stress on an a-Si:H TFT under different mechanical strain. The influence of mechanical strain on the performance of an hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) with different channel length and width on metal foil substrate under uniaxial compressive or tensile strain was studied, where the strain is parallel to the TFT source-drain current path. The process of TFT with the maximum temperature 190¢XC exhibited a field-effect mobility of 0.1 cm2/Vs and a threshold voltage of 1.95 V and the leakage current of less than 10-13 A. The TFTs were strained by inward (compression) or outward (tension) cylindrical bending. The mobility had a slightly change under the mechanical strain, which was due to the change in the disorder under bending strain. We also researched on the influence of uniaxial compressive (tensile) strain on the performance of a-Si:H TFTs under different AC stress conditions. When the a-Si:H TFTs were strained and applied AC stress, we found the performance of a-Si:H TFTs were affected more then the flat ones.

In this thesis, it mainly studies the performance characteristics of the bending losses in semiconductor waveguides and the quantum dots semiconductor optical amplifier. We used InP-subtract and InGaAlAs /InAlAs multiple quantum wells epitaxial wafer grown by MBE as our material(£fg=1.41£gm). We had successfully fabricated a series of bending strip-loaded waveguides. On the quantum dots semiconductor optical amplifier, symmetric InGaAlAs/GaAs quantum well structure is used to fabricate the optical waveguide. We have established an automatic optical measurement system to measure the device characteristics more accurately. Design respect of bending waveguide, we design a series of radius, is 60£gm, 80£gm, 110£gm, 170£gm,and 260£gm respectively, and utilize Fabry-Perot resonant, measurement and estimate the loss of bending waveguide in quantity. We find the bending waveguide loss as radius for 260£gm and contain deeply etching process was quite equal to straight waveguide loss. On the quantum dots semiconductor optical amplifier, we design a single mode waveguide and a broad area waveguide to compare the difference of their electron-hole combination situation. A single mode waveguide with longer cavity length had better combination situation than shorter (C311 of cavity length 4000£gm ,0.00066£gW *A/cm2). And the broad area waveguide had more better combination situation to single mode waveguide (C311 of cavity width 150£gm, length 4000£gm , 0.0966£gW *A/cm2). For the gain to the pump signal, C311 singe mode waveguide (emission peak:1211nm,pump signal:1260nm) could get a gain about 3.56dB¡Fand C374 singe mode waveguide (emission peak:1255nm,pump signal:1260nm) could get a gain about 6.1dB.

The objective of this project is synthesizing bipyridine-derived ligands in order to study DNA conformational bending. The synthesis of bipyridine derivatives has been investigated. 6,6’-Dibromo-2,2’- bipyridine and small scale of 6,6’-diformyl-2,2’-bipyridine have been successfully synthesized in the laboratory. The synthesis of large amount of a direct precursor to 6,6’-diformyl-2,2’- bipyridine in an multiple step way has been achieved. The synthesis of mono functionalized pyrene derivatives and of 1,6-dissymmetrically functionalized pyrene derivatives has been heavily studied. Successfully methods have been reported in this thesis. The complete assembly of bipyridine and pyrene units into the final ligands and their model has also been studied. Palladium borylation and Suzuki-Miyaura cross-coupling have been used to successfully connect the bipyridine with pyrene units. In addition to Suzuki-Miyaura methodology, the direct coupling of N,N’-dioxide-2,2’- bipyridine with aromatic bromides under palladium catalysis has been investigated. This method could be an alternative way to access to mono-substituted 6-bipyridines, symmetrically or even asymmetrically 6,6’-disubstituted-2,2’-bipyridine derivatives. / Thesis (Master, Chemistry) -- Queen's University, 2009-09-06 01:06:41.646

Folding empowers the user to change the form and function of a sheet of paper through a sequence of manipulations. Unfolding the once folded artefact produces a diagram that describes its own making that can be replicated at different scales using a new material. Architecturally, folding can be employed a morphogenetic solution to design a system that can be fabricated from a sheet material, that like paper, can be folded into a inhabitable structure. The ease and cost efficiency of fabrication based on folding can be used to design a system that executed using low cost materials can be used as a shelter that accommodates programmatic and aesthetic evolution. Thus, the system lends itself to being a transitional shelter for communities that have been displaced due to a natural disaster or other form of crisis. Technological advances in design and structural analysis can give the designer the power to define the complex process folding parametrically allowing the input a real-time feedback based design based on an a folding inspired algorithm.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 24, 2008) Includes bibliographical references.

Thesis (M. Eng.), Memorial University of Newfoundland, 1999. / Bibliography: p. 52.

Orientador: Antonio Accioly / Banca: José Geraldo Pereira / Banca: José Wadih Maluf / Banca: Ilya Lvovich Shapiro / Banca: João Barcelos Neto / Resumo: A gravitação quadrática em (2 + 1)D, ao contrário da gravitação tridimensional de Einstein, é localmente não trivial e possui um potencial extremamente bem comportado. Analisa-se esta teoria neste trabalho. Obtém-se a solução geral das equações de campo linearizadas numa versão tridimensional do gauge de Teyssandier, e a partir desta encontra-se a solução geral no caso de uma fonte pontual estática. Esta métrica se assemelha à métrica quadridimensional relativa a uma corda cósmica reta com simetria de gauge do tipo U(1). Existe uma força gravitacional atuando sobre uma partícula teste movendo-se em baixa velocidade, o que não acontece no contexto da relatividade geral em (2 + 1)D, e raios luminosos sofrem deflexão gravitacional. Considera-se também as mudanças que ocorrem quando um termo topológico de Chern-Simons é adicionado à gravitação quadrática em (2 + 1)D. Acha-se que o inofensivo modo escalar massivo da última, dá origem a um problemático ghost massivo de spin O, enquanto que o ghost massivo de spin 2 é substituído por duas partículas físicas massivas, ambas de spin 2 / Abstract: Quadratic gravity in (2 +1)D, unlike three-dimensional Einstein's gravity, is locally nontrivial and has an extremely well-behaved potential. Here we consider this theory. The general solution of the linearized field equations in a three-dimensional version of the Teyssandier gauge is obtained, and from that the solution for a static pointlike source is found. This metric greatly resembles the four-dimensional metric of a straight U(1)-gauge cosmic string in the framework of linearized quadratic gravity. It is found that a gravitational force is exerted on a slowly moving test particle, a feature not present in general relativity in (2 + 1)D. The deflection of light rays is analyzed as well. We also consider the changes that occur when a topological Chern-Simons term is added to quadratic gravity in (2 + 1)D. It is found that the harmless massive scalar mode of the latter gives rise to a troublesome massive spin-0 ghost, while the massive apin-2 ghost is replaced by two massive particles both of spin-2 / Doutor

The processing of materials has become a specialist field and the industry will continue to grow due to rising costs in labour and raw materials which has forced many automotive industry suppliers to invest heavily in this field. In order to be relevant and competitive in today’s industrial world, companies in South Africa are now forced to dedicate billions of rands in profits to research and development. Metals like titanium are finding favour with automotive and aviation companies in pursuit of savings in fuel consumption. This saving is achieved by reducing weight on aircraft and automobiles yet still meeting acceptable and improved structural integrity. In-depth research into the behaviour of various materials under varying loading conditions is therefore essential. The study on the processing of commercially pure grade 2 titanium alloy plates focuses on the development of process parameters for bending the material using a 4kW Nd: YAG laser to an approximate radius of curvature of 120mm. The resulting mechanical properties of laser formed plates are then compared to those obtained from mechanically formed samples. The titanium parent material was used to benchmark the performance of formed samples. The effect of process parameters on the mechanical properties and structural integrity also formed part of this study. To obtain the bending parameters for laser forming, various combinations of processing speeds and laser powers were used. The line energy is dependent on the power and scanning velocity parameters and these are shown in table 1. The laser power, line energy and scanning velocity were the main parameters controlled in this study and the beam diameter remained unchanged. Residual stress analysis, micro-hardness and fatigue life testing were carried out to analyse mechanical properties and the structural integrity of the plate samples. Microstructural analysis was also done to observe changes in the material as a result of the forming processes. From the results it is evident that laser forming is beneficial to the hardness of titanium but detrimental to the fatigue life at higher line energies. Residual stress analysis showed the amount of stress within the study samples increased with each forming operation. This information was vital in the analysis of the fatigue life of titanium. A fatigue life prediction model was developed from this study and it shed some light on the behaviour of titanium in fatigue testing. The model could be used to predict fatigue life when no fatigue data is available for commercially pure grade 2 titanium alloy plates. In conclusion, this study helped establish parameters that could be used to bend titanium while the analysis of mechanical properties showed the limits of working with this alloy.

The processing of materials has become a specialist field and the industry will continue to grow due to rising costs in labour and raw materials which has forced many automotive industry suppliers to invest heavily in this field. In order to be relevant and competitive in today’s industrial world, companies in South Africa are now forced to dedicate billions of rands in profits to research and development. Metals like titanium are finding favour with automotive and aviation companies in pursuit of savings in fuel consumption. This saving is achieved by reducing weight on aircraft and automobiles yet still meeting acceptable and improved structural integrity. In-depth research into the behaviour of various materials under varying loading conditions is therefore essential. The study on the processing of commercially pure grade 2 titanium alloy plates focuses on the development of process parameters for bending the material using a 4kW Nd: YAG laser to an approximate radius of curvature of 120mm. The resulting mechanical properties of laser formed plates are then compared to those obtained from mechanically formed samples. The titanium parent material was used to benchmark the performance of formed samples. The effect of process parameters on the mechanical properties and structural integrity also formed part of this study. To obtain the bending parameters for laser forming, various combinations of processing speeds and laser powers were used. The line energy is dependent on the power and scanning velocity parameters and these are shown in table 1. The laser power, line energy and scanning velocity were the main parameters controlled in this study and the beam diameter remained unchanged. Residual stress analysis, micro-hardness and fatigue life testing were carried out to analyse mechanical properties and the structural integrity of the plate samples. Microstructural analysis was also done to observe changes in the material as a result of the forming processes. From the results it is evident that laser forming is beneficial to the hardness of titanium but detrimental to the fatigue life at higher line energies. Residual stress analysis showed the amount of stress within the study samples increased with each forming operation. This information was vital in the analysis of the fatigue life of titanium. A fatigue life prediction model was developed from this study and it shed some light on the behaviour of titanium in fatigue testing. The model could be used to predict fatigue life when no fatigue data is available for commercially pure grade 2 titanium alloy plates. In conclusion, this study helped establish parameters that could be used to bend titanium while the analysis of mechanical properties showed the limits of working with this alloy.

This study was undertaken in order to determine analytically the magnitude of the secondary (i.e., joint deflection induced) moments in the continuous glued-laminated chords of bowstring timber trusses. Traditionally, these moments have been assumed to be small and therefore neglected. The American Institute of Timber Construction makes no mention of these moments in their recommended design procedure.