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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

Defects and Impurities in CdTe : An ab Initio Study

Lindström, Anna January 2015 (has links)
In this thesis defects and impurities in CdTe have been studied with ab initio methods. CdTe is a II-VI semiconductor with many important applications such as γ- and X-ray detectors, solar cells and medical imaging. Even though CdTe has been studied for more than 70 years, some of its properties connected with defects and impurities, are still shrouded in mystery. Todays experimental techniques are highly developed and can provide rather detailed data, but require elaborate theoretical analysis. Here ab initio modelling comes into play and in particular density functional theory (DFT). When reviewing different theoretical studies of defects and impurities in CdTe, one finds a vast number of discrepancies between experiment and theory. Mismatches appear even between different theoretical studies. Although many problems, such as, for example, the semiconductor band gap underestimation or the spurious interaction between charged defects, are avoided by employing corrections or implementing new functionals, some of them still remain. Employing the hybrid functional HSE06, the following topics were studied in this thesis: - Te antisites: Experimental data predict the defect state to appear in the middle of the band gap, thus "pinning" the Fermi level. In contrast, our calculations show that Te antisite alone cannot be the reason for the Fermi level pinning, since it does not form a defect level in the middle of the band gap. Instead we propose that charge compensation between Te antisites in a (+2) state and Cd vacancies in a (-2) state explains the Fermi level pinning. - Cd vacancy: Electron paramagnetic resonance experiments clearly show the existence of a hole polaron for the (-1) charged vacancy. But DFT studies report a completely delocalised hole. In our studies, for the first time, this state was found in its proper geometrical configuration with a hole localisation stabilised by a Jahn-Teller distortion, thereby removing the discrepancy between experiment and theory. - Cd chalcogenides: Additionally, with particular focus on the hole localisation problem, the series of isovalent compounds (CdTe, CdSe and CdS) was studied to understand the mechanism of hole polaron formation. We explain the trend of the hole localisation in terms of Coulomb interaction, explicitly showing that the effect of electron correlation is negligible. - Cl-doped CdTe: The formation of a Cl - Cd vacancy complex explains the selfcompensation and selfpurification mechanism. We find Cl to annihilate the hole polaron. - Te antisite under deformation: In an attempt to tailor the energy position of the Te antisite defect level in the CdTe band gap, we studied CdTe under different deformations. It is shown that by a carefully chosen deformation the defect levels can be pushed closer to the valence and/or conduction band and hence the CdTe detector performance may be improved.
2

Vliv Vojtovy reflexní lokomoce na pohybový aparát u pacientů s míšním poškozením / Vojta reflex locomotion impact to the locomotor system of the patients with spinal cord

Kohutová, Veronika January 2013 (has links)
The aim of this thesis was to evaluate the Vojta method therapy impact to the muscles function of the upper limbs of patients with tetraplegia. This is a pilot study, which was attended by five probands. To objectify the results, the method of surface electromyography was adopted. EMG activity of 14 muscles of the upper limbs and shoulder girdle during selected movements before and after therapy was recorded. The choice of therapeutic positions and activation zones was individual. Although a few muscles show significant changes, statistically considerable influence of the therapy cannot be confirmed from the obtained results. But from the point of view of clinical observation and patients 'subjective feelings an obvious difference can be seen. Therefore, it may be in the future advantageous to monitor the impact of Vojta method to locomotor system through clinical methods such as functional tests, tests of independence, range of motion or kinematic analysis.
3

Justice et justesse de l'indemnisation. Acteurs et dispositifs de l'État providence à l'épreuve du scandale de l'amiante

Pillayre, Héloïse 06 September 2017 (has links)
Cette thèse vise à comprendre comment les acteurs concernés par un drame collectif de grande ampleur, ici le scandale de l’amiante, tentent de se mettre d’accord quant à ce qui constitue une juste réparation des dommages engendrés. Le scandale de l’amiante a donné naissance à des innovations au niveau de l’indemnisation des victimes, avec la création d’un Fonds d’indemnisation (le Fiva), et la rénovation du dispositif de la « faute inexcusable de l’Employeur » devant les Tribunaux des Affaires Sanitaires et Sociales. Ces innovations ont questionné le système d’indemnisation traditionnel des Accidents du Travail et des Maladies Professionnelles, système consistant en une indemnisation forfaitaire reposant sur un système de gestion paritaire. Il s’agit alors de comprendre comment les dispositifs d’indemnisation qui font suite à un scandale sanitaire coexistent avec les dispositifs issus de l’État-Providence mis en place en 1946, et comment ces différents dispositifs permettent l’expression de différents types de citoyenneté. Afin de répondre à ces questions, la thèse s’attache à décrire les évaluations normatives portées par les acteurs sur les dispositifs d’indemnisation, ainsi que la manière dont ces évaluations se confrontent les unes aux autres. Fondée essentiellement sur des entretiens avec les acteurs concernés et sur des ethnographies d’associations locales, la thèse articule trois niveaux d’analyse :Les acteurs institutionnels qui ont participé à la création ou à la rénovation des dispositifs d’indemnisation des maladies de l’amiante (représentants syndicaux et associatifs, avocats, représentants patronaux, représentants des pouvoirs publics). La thèse montre comment les acteurs attribuent différentes finalités aux dispositifs d’indemnisations et évaluent différemment leurs principes de fonctionnement. Elle met en évidence une fracture importante entre représentants syndicaux et associatifs qu’elle tente d’expliquer.Les associations locales visent à aider les personnes à obtenir indemnisation. La thèse s’attache à décrire la diversité des modes de structuration et de fonctionnement de ces associations, qui émanent de communautés variées, et montre l’influence de cette diversité sur la manière dont elles viennent en aide aux victimes.Les parcours d’indemnisation des victimes elles-mêmes et des ayants droit sont ensuite analysés, en s’attachant à mettre l’accent sur la diversité des manières dont ceux-ci formulent ce qui leur arrive, expriment des reproches, et réclament réparation. La thèse met en évidence l’influence de la carrière des personnes et des associations locales sur leurs itinéraires. / In this dissertation I aim to understand how actors affected by a major collective drama, here the asbestos scandal, try to reach agreement on what constitutes a fair compensation of the harms that have been caused. The asbestos scandal has given birth to innovations in the way victims are compensated, through the creation of a Compensation Fund (the Fiva) and the renewal of the procedure of « Faute inexcusable de l’employeur ». These innovations have come to question the traditional compensation system for Work-Related Accidents and Illnesses, which consisted of a lump-sum compensation based on a system of joint management between representatives of trade-unions and employers. The objective is to understand how compensation mechanisms that are created following a public health scandal coexist with mechanisms grounded in the welfare state that were put into place back in 1946, and how these different mechanisms allow the expression of different types of citizenship. In order to respond to these questions, the dissertation describes the normative evaluations expressed by different actors on these compensation mechanisms, as well as the way in which these evaluations confront each other. The dissertation is based mainly on interviews with the involved actors and on ethnographies of local associations, and articulates three analytical levels:The institutional actors that have participated in the creation or renovation of compensation mechanisms of asbestos-related diseases (union and association representatives, lawyers, employer representatives, government agents). The dissertation shows how actors attribute different ends to the compensation mechanisms and evaluate their principles and functioning differently. The thesis brings to light an important divide between union representatives and associations, which it tries to explain. Local associations seek to aid persons in obtaining compensation. The dissertation describes the diversity in the structuration and mode of functioning of these associations, that emanate from different types of communities, and shows the influence of this diversity on the way in which these associations provide aid to victims. Finally, the compensation paths of victims themselves and beneficiaries are analyzed, accentuating the diversity of ways in which they name what is happening to them, in how they express blame, and in how they claim compensation. The dissertation brings to light the influence of persons’ careers and of local associations on the itineraries they pursue.
4

Employment dynamics and innovation / Dynamiques de l'emploi et innovation

Calvino, Flavio 06 October 2016 (has links)
Cette thèse de doctorat porte sur la dynamique de l’emploi dans les entreprises et sur la relation entre la dynamique de l’emploi et l’innovation, avec une attention particulière portée sur les entreprises nouvellement créées. Cette thèse conceptualise théoriquement et analyse empiriquement les différents aspects de l’interaction complexe entre le changement technologique et la dynamique de l’emploi, en se concentrant sur les effets hétérogènes des différents types d’innovation sur la croissance de l’emploi. Compte tenu le rôle primordial joué par les nouvelles et jeunes entreprises dans le processus de destruction créatrice et leur apport à la création globale de l’emploi, cette thèse fournit une caractérisation de la contribution nette d’emplois des nouvelles entreprises dans un nombre important de pays, en utilisant des données micro-agrégées issues d’une nouvelle base de données. En outre, elle analyse comment un certain nombre de caractéristiques institutionnelles affectent la création nette d’emplois dans les start-ups, en se concentrant sur les effets hétérogènes des politiques sur les nouvelles entreprises et les entreprises déjà existantes. Cette thèse étudie enfin une caractéristique particulière des lois de distribution des taux de croissance de l’emploi, c’est-à-dire la volatilité de la croissance de l’emploi, que non seulement se révèle être une médiation cruciale des effets des politiques sur la création nette d’emplois, mais a aussi d’importantes implications à la fois micro- et macroéconomiques. / This doctoral thesis focuses on employment dynamics in firms, and on the relationship between employment dynamics and innovation, with a particular focus on the entry process. It conceptualizes theoretically and analyses empirically different aspects of the complex interaction between technical change and employment dynamics, focusing on the heterogeneous effects of different types of innovation on employment growth. In the light of the prominent role of newly-born firms in shaping the creative destruction process and contributing to overall job creation, this thesis provides a characterization of the net job contribution by surviving entrants across a significant number of countries. Using newly collected representative micro-aggregated data, it further analyses whether and how a number of institutional characteristics affect start-ups’ net job creation, focusing on the heterogeneous effects of policies on entrants and incumbents. This thesis finally characterizes a particular feature of the employment growth distributions – employment growth volatility – that not only proves to be crucially mediating the effects of policies on entrants’ net job creation, but also has important micro and macroeconomic implications.

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