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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

Differences among Asians and White Americans in Racial Prejudice: A Function of Contact with Out-group Members

Lee, WooJun 2011 May 1900 (has links)
In examining the racism in sport literature, two general trends emerge: (a) a focus on Western sport organizations and the prejudice expressed by Whites in these entities; and (b) the tendency to document the occurrence of prejudice without examining key antecedent conditions. The purpose of this study was to address these gaps in the literature. Specifically, I compare the racial prejudice of White Americans with Asians and also examine the degree to which intergroup contact impacts this level of prejudice. Data were collected from Asian (n = 104) and White American (n = 100) college students. They completed a questionnaire that assessed their contact with African Americans as both team mates and exercise partners, their intergroup anxiety, and racial prejudice. Results indicate that all of the study variables were significantly correlated with one another. As expected, a multivariate analysis of variance further illustrated that Asians, relative to Whites, expressed more anxiety and prejudice, while also having less contact with African Americans. Finally, results from a moderated regression indicated that the relationship between nationality and intergroup anxiety was moderated by contact with African Americans as team mates and as exercise partners. In both cases, the lack of contact resulted in greater anxiety for Asians than it did for Whites. This study contributes to the literature by explicitly examining racial bias across cultures. In addition, the findings point to the importance of diversity in exercise and team settings as a way of reducing racial prejudice. That is, since in being contact with African Americans as team mates and exercise partners helped to reduce intergroup anxiety, efforts should be made to increase racial diversity in exercise and sport team settings.
2

Transport quantique en formalisme des fonctions de Green et interaction électron-photon pour la modélisation de cellules photovoltaïques / Quantum transport in Green’s function formalism and electron-photon interaction for modeling photovoltaic cells

Giraud-berbezier, Aude 11 December 2013 (has links)
Ce document présente notre travail sur la modélisation en formalisme des fonctions de Green (abrégé formalisme de Green) du transport quantique et de l’intéraction éléctron-photon dans une cellule photovoltaïque composée d’une boîte quantique connectée à deux nanofils semi-infinis, La simulation numérique a été réalisée sur le cluster de calculs MERLIN (IM2NP). Nous présentons le formalisme de Green en général puis appliqué à cellule. Le fonctionnement général de la cellule est déduit de son diagramme de bande qui comporte des contacts sélectifs. Ensuite, nous présentons les résultats obtenus dans l’approximation de bande plate, qui simplifie le contact aux nanofils. Ceux-ci mettent en lumière des effets intriqués du couplage tunnel (couplage entre la boîte et les nanofils) et du couplage optique (couplage avec la lumière). Nous présentons ensuite un calcul analytique effectué dans le régime de fort couplage tunnel et qui explique le fonctionnement contre-intuitif du couplage tunnel dans ce régime. Nous observons également une transition dans le processus de production du courant entre le régime de fort couplage tunnel et le régime de fort couplage optique. Ensuite, nous sortons de l’approximation de bande plate et découvrons que les effets contre-intuitifs sont toujours valides, même si le modèle analytique lui ne l’est plus. Nous présentons le nouvel effet induit par la nouvelle forme du couplage aux réservoirs hors de l’approximation de bande plate: la courbe courant-tension présente une conductance de shunt négative. Cela n’a jamais été observé dans une cellule photovoltaïque auparavant. Enfin, nous présentons une réalisation possible de notre cellule. / This document present our work on the modeling of quantum transport coupled to electron-photon interaction in a solar cell composed of one quantum dot connected to two semi-infinite quantum wires. The proposed cell based on a dot in a wire, is a concept imagined in order to investigate quantum effects inside 1D structures in contact with 0D ones. The numerical simulation powered on the Merlin cluster (IM2NP) relies on Green’s function formalism. The philosophy of Green’s function formalism is introduced and then applied to the photovoltaic cell. An overview of the functioning of the cell is given. Results on the cell are presented in the wide band limit (approximation that simplifies the contact to wires). We observe an interlinked impact of the tunneling coupling (dot-wires coupling) and the optical coupling (to light) on the current. In the strong tunneling regime, an increase of the tunneling coupling decreases the current and similarly in the strong optical coupling regime, an increase of the optical coupling decreases the current. We investigate the counter-intuitive impact of the tunneling coupling in the strong tunneling regime through analytical calculations, considering only the first loop of the numerical code instead of the whole self-consistent process. We observe a transition in the current creation process while switching from the strong tunneling regime to the strong optical coupling regime. Results on the cell beyond the wide band limit approximation are presented in which the system exhibits another atypical response to illumination: I-V curve exhibits a negative shunt conductance! Finally, a realization proposal for the concept cell is described.

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