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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.
201

Deep level transient spectroscopic study of nitrogen-implanted ZnO single crystal

Ding, Guangwei, 丁光炜 January 2010 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
202

Deep level transient spectroscopic study of intrinsic defects in particle-irradiated ZnO single crystal materials

Lu, Xiaohong, 吕小红 January 2012 (has links)
Zinc oxide (ZnO), as a Ⅱ-Ⅵ compound semiconductor with a wide direct band gap, has attracted great attention from the worldwide researchers for its potential application in the fields of spintronics and optoelectronics. At present research about the defects in ZnO and ZnO-based materials is still far from complete. The deep level defects in melted grown ZnO single crystal induced by helium ions implantation and electron irradiation, as well as their thermal evolution, were studied in this research using the technique of deep level transient spectroscopy (DLTS) and photoluminescence (PL). DLTS results indicated that, besides E3 (????~0.28 ????) trap which was widely observed in the as-grown ZnO samples, the deep level with ????~0.92 ???? was also indentified in the helium-implanted ZnO samples, which was introduced by the ion implantation and tentatively assigned to be the oxygen vacancy (VO). This deep level was removed after 350 oC annealing in argon gas. Annealing at 350 oC also brought along a new deep level with ????~0.66???? into helium-implanted samples which could be annealed out by 650 oC annealing in argon gas. The electron irradiation induced a deep level with ????~0.59 ???? into ZnO, which was probably associated with the singly charged state of VO. This deep level also tended to be removed at 350 oC annealing in argon gas. The PL spectra revealed that both helium implantation and electron irradiation could improve the bound-exciton peak. Helium implantation also introduced defects emission at 1.90 eV , which was the red luminescence band, into the ZnO single crystal materials. This red luminescence band peak might be associated with DAP recombination. Electron irradiation might restrain the green luminescence in ZnO single crystal. The fine structures could disappear as the measurement temperature increased, leaving the green luminescence band only. / published_or_final_version / Physics / Doctoral / Doctor of Philosophy
203

Beyond affective valence : the effect of different emotions on cognitive processing and persuasion from a certainty-congruent approach

Kwon, Ohyoon 03 February 2015 (has links)
This research investigates the role of emotion in the persuasion process by establishing a novel relationship between emotion and construal level. Built on cognitive appraisal theories, this research proposes that the certainty appraisal components of emotions exert a direct influence on an individual’s representation of information at a high versus low construal level. The findings indicate that individuals primed to feel emotion low on certainty appraisals construe behaviors or events at a high level and estimate uncertain events as more likely to happen, while those primed to feel emotion high on certainty appraisals characterize behavior or events at a low level and evaluate uncertain events as less likely to occur (Study 1 & Study 2). Further, such a fit (vs. nonfit) between an individual’s emotional state and the construal level at which product benefits in an advertising message are represented lead to a more favorable evaluation of the message and product (Study 3). The findings from this dissertation study also illustrate that uncertainty-related emotion eliciting a high-level construal mindset leads to a cognitive shift toward relying more on nonalignable attribute differences and a greater preference for the nonalignable-better brand although individuals usually rely more on alignable attribute differences and favor the alignable-better brand (Study 4). Accordingly, these outcomes occur because the certainty appraisal components of emotions influence mental construal levels. / text
204

Validation of level set contact angle method for multiphase flow in porous media

Verma, Rahul 24 February 2015 (has links)
Pore-scale simulation has become increasingly important in recent years as a tool to understand multiphase flow behavior. Wettability affects aspects of flow such as capillary-pressure saturation curves, residual saturation of each phase, and relative permeability. Simulation of wettability at the pore-scale is still a non-trivial problem, and many different approaches exist to model it. In this work, we implement a variational level set formulation to impose different contact angles at the solid-fluid-fluid contact line for two-phase flow in simple rhomboidal pore geometries, and calculate the maximum mean curvature (equivalently capillary pressure) for each case. We compare our results with a detailed set of analytical and experimental results in a range of pore geometries of varying wettability from Mason and Morrow (1994), and demonstrate the accuracy of this method. While the simulations shown are for relatively simple geometries, the method has the ability to handle arbitrarily complex geometry (such as input from X-ray microtomography imaging). / text
205

Automated traceability in fruit export chains in South Africa

Fourie, LCH, Evans, A, Olivier, R January 2007 (has links)
A B S T R A C T Deregulation of the South African fruit export industry in 1997 caused fragmentation in the supply chain. This led to significant inefficiencies and difficulty in responding to increasingly stringent legal and traderelated traceability requirements. Currently, the South African fruit export industry does not provide a sufficient level of traceability at supply chain level. The consumer packaged goods industry has developed e-commerce building blocks based on global standards. These building blocks offer automated traceability of fruit exports, as well as significant benefits impacting the bottom line, to companies of all sizes. The e-commerce building blocks also provide solutions to the two main challenges faced by the fresh produce supply chains, namely traceability requirements and the need for additional efficiencies. The e-commerce building blocks are available to the South African fruit export industry to enable traceability, as well as to provide significant efficiency benefits. It has been found that early adoption of the e-commerce building blocks will result in a strategic advantage over the southern hemisphere competitors and that automated traceability is feasible for the South African fruit export industry. This article describes the cohesiveness, willingness to participate and supportive thinking of representatives from the important fruit export industry in South Africa, which are necessary to create the critical mass for the implementation of such an automated traceability system.
206

Uncovering learning outcomes: explicating obscurity in learning of aesthetics in design and technology education

Haupt, G, Blignaut, S 01 May 2007 (has links)
Abstract Education and training interventions can be evaluated through the success of learning outcomes. Kirkpatrick's four-level model is a widely accepted and highly popular evaluation tool. However, some criticise the model's shortcomings. This article will examine the extent to which the four-level model can evaluate design and technology students' learning about aesthetics after an intervention by reporting our use of an augmented version of the four-level model. We examine the results in terms of students' reaction to the intervention, their long-term learning and their behaviour changes by studying their visual analyses and drawings through segment codes. We found that, in order to uncover the obscurities imbedded in aesthetics and to explicate the complexities, we could not use the four-level-model on its own, but had to revert to a more augmented version.
207

The development of positron deep level transient spectroscopy using variable energy positron beam and conventional deep level transientspectroscopy using digital capacitance meter

張敬東, Zhang, Jingdong. January 2002 (has links)
published_or_final_version / Physics / Master / Master of Philosophy
208

Working together as one?Exploring the implementation and community perception of catchment management in Samoa.

Apelu-Uili, Toiata January 2015 (has links)
Water is a constantly changing resource by way of the hydrological cycle. It is unevenly distributed and crosses boundaries of all kinds i.e. political, social, cultural and natural. Samoa is a small developing state in the Pacific Region that is facing rapid pressure with its water resource availability. Consequently, access to and use of water resources has created tensions between water resources regulators, water utilities and villages. Therefore, managing and governing of water becomes a challenging process that has to take into account the complexity of both nature and society. With the emergence of the Integrated Water Resources Management (IWRM) framework, a greater social acceptance and importance has been given to catchment scale management and governance. Nowadays, many countries including Samoa, have embraced this appealing concept where catchments are seen as natural units for water governance and management. This study used a social qualitative approach, aimed to investigate the implementation of catchment management and examine local community perceptions of catchment management, using Apia Catchment as case study. It is based on a conceptual framework of the concept of scale i.e. set out in recent debates and ideas in the arena of catchment scale water governance and management. The primary data was collected from community focus groups within two villages of Apia Catchment, and semi-structured interviews with government agencies involved in the Water and Sanitation Sector programmes. The findings revealed a shift in water resources management and governance and a spatial scale mismatch in Apia Catchment management. According to government officials, the catchment approach is a ‘management tool’ adopted to improve the coordination between water users and to promote local ownership of catchment activities amongst individual villages. However, several challenges arose around land ownership, monetary cost, community resistance and issues outside of catchment areas when implementing catchment management. Despite the challenges that government officials encountered and the concerns raised by the communities, catchment scale management is still being adopted in Samoa. With the adoption of catchment management, many individual villages within Apia Catchment are expected to make decisions collectively. However, some local groups have concerns about the use of the term ‘boundary’, the possibility of the government taking over their land and the proposed catchment-based authority taking precedence over pre-existing cultural hierarchy. Overall, this research reveals that catchment management is often viewed or seen by government as a ‘one size fits all’ notion that ignores the range of the socio-ecological realities on the ground. This study shows that in order to design better water resources policies and strategies that are fully applicable and workable for Samoa, it is very important to identify these mismatches in scales (e.g. spatial and administrative) and levels (e.g. national and local). Understanding scales and associated levels is critical to understanding the whole system and can reduce possible consequences of mismatches due to lack of interaction and collaboration between levels and scales. Local villages have expressed their opinions on how to enhance catchment management and this could perhaps be useful for government in terms of implementation. Based on the results, recommendations are made for water resources managers to assess the importance of different levels and their interactions but, more importantly, to consider how local communities perceive catchment management.
209

Östersjömiljarderna - en studie i svensk partipolitik

Gustafsson, Peter January 2010 (has links)
Syftet med uppsatsen är att analysera Gunnar Sjöbloms modell om programrealisering utifrån ett fall, Östersjömiljardprojektet, samt att följa upp modellen med aspekten om Multi-level governance. Detta görs med hjälp av tre frågeställningar. För att uppfylla syftet har jag med hjälp av en textanalys bearbetat material hämtat från Rikslex, Riksdagens arkiv, i form av propositioner, motioner, betänkande, och protokoll. Den teoretiska utgångspunkten har tagits ifrån Gunnar Sjöbloms modell som bygger på partistrategi i ett flerpartisystem. Partiernas främsta mål är att uppnå programrealisering. För att åstadkomma detta krävs inflytande på tre arenor: väljararenan, den interna arenan och den parlamentariska arenan.Östersjömiljardprojektet var ett förslag i sysselsättningspropositionen 1995 som byggde på att en miljard kronor skulle ingå i en fond avsatt för att främja svensk export inom områdena livsmedel, energi, ömsesidigt kunskapsutbyte, stärkt infrastruktur samt samarbete för att miljöskydd runt Östersjön. De områden som ingår i projektet är nordvästra Ryssland, Estland, Lettland, Litauen samt Polen. Resultatet visar att Sjöbloms modell är hållbar för det valda fallet. För att avgöra om det är ett fall av multi-level governance krävs ytterligare forskning på vilka påtryckningar utanför den politiska arenan som var betydande för beslutet.
210

Transferability of community-based macro-level collision prediction models for use in road safety planning applications

Khondaker, Bidoura 11 1900 (has links)
This thesis proposes the methodology and guidelines for community-based macro-level CPM transferability to do road safety planning applications, with models developed in one spatial-temporal region being capable of used in a different spatial-temporal region. In doing this. the macro-level CPMs developed for the Greater Vancouver Regional District (GVRD) by Lovegrove and Sayed (2006, 2007) was used in a model transferability study. Using those models from GVRD and data from Central Okanagan Regional District (CORD), in the Province of British Columbia. Canada. a transferability test has been conducted that involved recalibration of the 1996 GVRD models to Kelowna, in 2003 context. The case study was carried out in three parts. First, macro-level CPMs for the City of Kelowna were developed using 2003 data following the research by GVRD CPM development and use. Next, the 1996 GVRD models were recalibrated to see whether they could yield reliable prediction of the safety estimates for Kelowna, in 2003 context. Finally, a comparison between the results of Kelowna’s own developed models and the transferred models was conducted to determine which models yielded better results. The results of the transferability study revealed that macro-level CPM transferability was possible and no more complicated than micro-level CPM transferability. To facilitate the development of reliable community-based, macro-level collision prediction models, it was recommended that CPMs be transferred rather than developed from scratch whenever and wherever communities lack sufficient data of adequate quality. Therefore, the transferability guidelines in this research, together with their application in the case studies, have been offered as a contribution towards model transferability to do road safety planning applications, with models developed in one spatial-temporal region being capable of used in a different spatial-temporal region.

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