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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.
61

Intramolecular electron transfer in mixed-valence triarylamines

Lancaster, Kelly. January 2009 (has links)
Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2010. / Committee Chair: Bredas, Jean-Luc; Committee Member: Kippelen, Bernard; Committee Member: Marder, Seth; Committee Member: Orlando, Thomas; Committee Member: Sherrill, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.
62

Intertextualidade e ironia na interpretação de charges

Matias, Avanúzia Ferreira January 2010 (has links)
MATIAS, Avanuzia Ferreira. Intertextualidade e ironia na interpretação de charges. 2010. 131f. Dissertação (Mestrado em Linguistica) – Universidade Federal do Ceará, Departamento de Letras Vernaculas, Programa de Pós-Graduação em Linguística, Fortaleza-CE, 2010. / Submitted by nazareno mesquita (nazagon36@yahoo.com.br) on 2012-06-25T13:59:08Z No. of bitstreams: 1 2010_diss_ AFMatias.pdf: 1279473 bytes, checksum: df26b5fa1de6523e6c02583404e30187 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2012-08-02T14:34:27Z (GMT) No. of bitstreams: 1 2010_diss_ AFMatias.pdf: 1279473 bytes, checksum: df26b5fa1de6523e6c02583404e30187 (MD5) / Made available in DSpace on 2012-08-02T14:34:27Z (GMT). No. of bitstreams: 1 2010_diss_ AFMatias.pdf: 1279473 bytes, checksum: df26b5fa1de6523e6c02583404e30187 (MD5) Previous issue date: 2010 / O presente trabalho desenvolveu -se a partir da nossa curiosidade de estudar algu mas especificidades do gênero charge. Iniciamos nossa investigação explorando o contexto histórico no qual a char ge foi criada, seu desenvolvimento e evolução ao longo do tempo até chegar às características atuais. Tratando-se de um trabalho de Linguística Aplicada, objetivamos analisar a interpretação de char ges por universitários do curso de Letras da Universidade Federal do Ceará, tomando como referência a intertextualidade e a ironia. A primeira porque este é um elemento fundamental para a construção do discurso chárgico. A segunda porque este é um recurso considerável para instigar a crítica a um fato atual dentro do contex to social no qual ocorre. Para explorar os elementos discutidos na interpretação das charges, baseamo-nos no dialogismo e na polifonia conceituados por Bakhtin. Com relação às categorias selecionadas para compor o quadro teórico desse trabalho, analisamos a intertextualidade com base em níveis e técnicas criados por Bazerman (2006). Para analisar a ironia, lançamos mão de estudos de Brait (2008), qu e concebe este recurso linguístico como um fenômeno polifônico. Nosso trabalho perscruta se para construir sentido na interpretação da char ge e se para entender sua crítica é necessário que haja uma correlação direta entre a compreensão da intertextualidade e da ironia. Após a análise dos dados, constatamos que os elementos intertextuais participam da construção do sentido em charge, mas não garantem o entendimento da ironia, e esta é muito menos perceptível quando a charge associa texto verbal e texto não-verbal. As charges são compreendidas mais facilmente quando possuem texto verbal, pois o leitor apoia-se nas pistas desse tipo de tex to para interpretar o contexto e, sem esse recurso, muitas vezes o sujeito não compreende a mensagem transmitida somente através do desenho. / genre charge. Nous avo ns commencé notre recherche en ex plorant le contexte historique dans lequel la charge a été créé, son développement et l'évolution au fil d u temps pour atteindre les caractéristiques actuelles. Comme il s'agit d'un travail de Lin guistique Appliquée, nous analysons l'interprétation des charges par des étudian ts du Cours de Lettres à l'Université Fédérale du Ceará, en tenant compte l'intertextu alité et l'ironie. La première, car est un élément fondamental pour la construction du discours de la charge. La seconde, parce que c'est un recours considérable pour engager un fait essentiel dans le contexte social actuel dans lequel il se produit. Pour explorer les éléments discutés dans l'interprétation des charges, nous nous appuyons sur le dialogisme et la polyphonie conceptualisés par Bakhtine. En ce qui concerne les catégories choisies pour composer le cadre théorique de cet étude, nous avons analysé l'intertextualité en niveaux et en techniques créées par Bazerman (2006). Pour analyser l'ironie, nous avons utilisé des études de Brait (2008), qui conçoit cette ressource linguistique comme une phénomène polyphonique. Notre travail examine si pour construire le sens dans l'interprétation de la charge et comprendre leur critique, il f aut avoir une corrélation directe entre la compréhension de l'intertextualité et de l'ironie. Après avoir analysé les donnés, nous avons constaté que les éléments intertextuels contribuent à la construction du sens de la perceptible lorsque la charge est associée à un texte verbal et à un texte non-verbal. Les charges sont comprises plus facilement quand elles ont un texte verbal, puisque le lecteur s'appuie sur les pistes de ce type de texte pour interpréter le contex te et, sans cette ressource, le sujet ne comprend pas souvent le message transmis seulement par le dessin.
63

Dois casos de interesse em movimento de carga espacial / Motion of spatial charge: two interesting situations

Raffaele Amazonas Novellino 20 June 1983 (has links)
Este trabalho apresenta dois problemas distintos. No primeiro, obteve-se a característica da corrente em função da voltagem em um dielétrico sob radiação, supondo-se que só um portador seja móvel, que recombinação e injeção da carga móvel através de um eletrodo. Na interface eletrodo-dielétrico foi imposta a condição de densidade de carga constante. No outro problema foi feita uma generalização do problema transiente clássico estudado por Many e Rakavy, usando a mesma condição anterior de densidade de carga constante no eletrodo injetor. Obteve-se soluções analíticas durante o 1º tempo de trânsito e de desenvolveu soluções por computador até o 3º tempo de trânsito. As oscilações amortecidas da corrente em torno do valor estacionário, também merece alguma atenção / Two distinct problems are treated here. In the first one, the relation between current and voltage in a dielectric under radiation is obtained, assuming only carrier to be mobile, recombination and injection of the mobile charge from the electrode. We have chosen for this last boundary condition a constant charge density at the electrode-dielectric interface. The second problem treated is a generalization of the classic transcient problem studied by Many-Rakavy, using the constant charge density boundary condition. Analytic solutions were obtained during the first transit time and computed ones for larger times. Some attention was given to the damped current oscillations approaching the steady state value
64

Optical charge injection into a gallium arsenide acoustic charge transport device

Beggs, Bruce Cameron January 1987 (has links)
There is a need for monolithic devices capable of spatial resolution in imaging and ionizing radiation detection. In this thesis, a GaAs acoustic charge transport device (ACT) was studied for this purpose. A new method of charge injection has been demonstrated for the ACT. Using near-infrared optical pulses incident through thin semi-transparent chromium windows, electron-hole-pairs were separated by the electric field in a depleted n-type channel region of the device. For light penetration less than the depth of the electron potential minimum, and for small injection levels, calculations indicated that electrons and holes were separated at their saturation velocities. Holes moving toward the surface of the substrate could recombine with electrons at an evaporated Schottky metal plate. Electrons moving toward the channel centre were bunched and transported by the electric field coupled to a <110> propagating surface acoustic wave (SAW) on (100) cut GaAs. Quantum efficiency, defined as the number of electrons collected at the output per incident photon on the GaAs surface, was greater than 9% at an optical wavelength of 730 nm. When compensation was made for the loss and reflection due to the chromium windows, the quantum efficiency was in excess of 24%. Charge transfer efficiency was greater than 0.992 with the ACT clocked at 360 MHz. The demonstrated optical injection technique may be of use in future ACT imaging devices. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
65

Dopady novely DPH v ČR / Impacts of the Amendment of VAT in the Czech Republic

Milnerová, Radka January 2011 (has links)
The result of this work will be the description of the historical development and the inclusion of VAT in the VAT system of taxation in Czech Republic. The thesis also explains VAT accounting and the most important concepts that relate to VAT itself. The work describes the VAT law and its consistency with other legislation. The practical part of the thesis will focus on the amendment of VAT, which came into force in 2011. The main goal is to describe the reverse-charge system and its changes between 2011 and 2012. The main objective of this work is to determine whether these changes affect the companies and how.
66

Processus de transfert de charge lors de l'intéraction d'ions de Li avec des surfaces métalliques et agrégats supportés / Electron transfer processes in scattring of ions on metal surface and on supported metal clusters

Shen, Jie 28 June 2012 (has links)
Ce travail porte sur la neutralization résonnante d’ions Li+ sur des métaux et agrégatsmétalliques supportés. La neutralization sur Pd(100) a été étudié, pour différentsparamètres. La neutralisation s’avère très efficace sur cette surface avec un travail desortie grand et est en contradiction avec ce qu’on attend dans le cadre des modèlestraditionnels. Il est proposé qu’une description du processus RCT modifié, issued’études précédentes sur des métaux nobles, doit être utilisé. Dans celle ci desprocessus de neutralisation survenant à des distances atome- surface faible ont lieu etaussi un comportement adiabatique du système aux faible énergies de collisions mèneà une neutralization efficace.Les résultats de l’étude des processus de transfert d’électrons lors de l’interactiond’ions de Li+ avec des agrégats d’or supporté sur HOPG avec Al2O3 sont présentés etdiscuté. L’imagerie STM pour les agrégats d’or supporté sur un substrat HOPG viergeet aussi un substrat de HOPG bombardé par des ions de AR sont présentés. Lesobservations révèlent que agrégats d’or forment préférentiellement des chaines 1D lelong des marches sur HOPG vierge. Dans le cas de HOPG bombardé, la taille et lahauteur des agrégats sont dépendants des défauts de surface.Nous avons trouvé que la neutralisation est très efficace sur les petits agrégats et engénéral est beaucoup plus grande que sur des surfaces de cristaux d'or. Nous montronsdes effets liés à la nature du substrat, comme dans le cas de l’alumine ou le cas desdifférences observées sur des chaines d’agrégats sur HOPG vierge et les agrégatsformés sur des défauts / The present work investigates the neutralization of Li+ ions on metals and supportedmetal clusters. Neutralization on a transition metal surface Pd (100) for differentparameters was studied. Highly efficient neutralization on this surface with a highwork functions was observed and contradicts our traditional views on resonant chargetransfer (RCT) mechanism. A modified RCT picture involving new neutralizationprocesses occurring at a short atom-surface distance and an adiabatic behaviourleading to efficient neutralization at large distances, that has emerged from previousstudies on noble metal surfaces appears in qualitative agreement with our data.The experimental results on the dependence of the Li neutralization on the Auclusters supported on different substrates are reported and discussed. As acomplement to this, a STM study into the morphology of Au nanoparticles on apristine HOPG substrate as well as Ar+ ions sputtered HOPG substrate has beenperformed. The observations reveal that Au clusters preferentially form onedimensional chains along steps on pristine HOPG. In the case of Ar+ ions sputteredHOPG substrate, the size and height of cluster are dependent on surface defects.We found that neutralization is very efficient on small clusters and in general muchlarger than on surfaces of gold crystals. We demonstrate existence of strongdifferences as a function of cluster support type as in case of alumina supports orcluster chains on HOPG and clusters on defects on HOPG terraces.
67

Photoinduced Charge Carrier Generation and Ground-state Charge Transport in Metal-Organic Frameworks For Energy Conversion

Li, Xinlin 01 December 2022 (has links) (PDF)
Metal-Organic Frameworks (MOFs), a class of porous materials realized via reticular construction of a plethora of organic linkers and metal nodes, have emerged as excellent candidates for light-harvesting compositions (LHC), photo or electrocatalysis. This is due to their ability to organize chromophores and metal nodes with desired functionalities, and remarkable porosity that allows efficient mass transfer of reactants and electrolytes. Recent studies have shown intriguing delocalized excited state of the orderly organized pigments in MOFs. Furthermore, the accessible pores/channels allow it to host complementary optical/redox active species within the frameworks by means of de novo or postsynthetic functionalization, as a manner for MOF compositions to integrate functionalities beyond photosensitizer, such as photo/electrocatalytic sites. In such multi-component assemblies, profound understanding of charge transfer and separation process is crucial to make the designed LHC efficient. Therefore, we could adopt chromophoric MOFs as a scaffold to systematically investigate photoinduced charge transfer by installing judiciously selected redox moieties into MOFs, whose unique electronic properties could define distinct electronic interplay with MOFs. From an aspect of further applications, photo-generated electrons can be utilized more efficiently by an external electric field applied on MOF films, which prolongs the charge-separation lifetime. For this purpose, sufficient electrical conductivity is necessary to allow charges delivered across the MOF film. Considering a large energy mismatch between the majority of traditional metal nodes including metal oxo clusters and carboxylic based struts, charge transport is defined by a slow hopping process, which hinders the harvesting of relatively short-lived separated charges. Hence, developing neoteric linkage chemistry is critically needed to overcome the charge-transport challenge.Keeping these points in mind, the scope of this dissertation mainly focuses on unraveling the fundamental principles of photoinduced charge transfer and separation, ground-state charge transport boosted by nontraditional coordination chemistry and incorporation of complementary redox species, and their substantial correlation with MOF-based photocatalysis, electrocatalysis and photoelectrocatalysis. The first chapter lays the foundational knowledge regarding generic properties (chemical and physical) of MOFs, and adopted typical postsynthetic functionalization method, namely, solvent-assisted ligand incorporation (SALI), and other physical processes including photoinduced charge and energy transfer among components within MOFs, and mechanism of electron transport, that has so far been understood, in MOFs driven by an external electric field and commonly used approaches to measure that. Chapter two and three reveal the rule to control photoinduced charge transfer in MOF compositions prepared by the installation of a series of zinc porphyrins possessing gradient excited-state and frontier-orbital energy that can define distinct charge-transfer driving force into the mesopore of a photosensitizing MOF, NU-1000. These compositions show potential for their utilization as artificial light-harvesting assemblies. Chapter four highlights new design for solid porous CO2 reduction catalysts realized by introducing cobalt phthalocyanine into NU-1000. Importantly, we interpreted the catalytic activity from the aspect of charge transport efficiency, by comparing with catalysts constituted by NU-1000 and different molecular catalysts. To harvest the photo-generated electrons, an external electric field can be applied on MOF films deposited on transparent electrodes under photoexcitation, for which sufficient electrical conductivity is a must. Therefore, in chapter five, a new semiconducting coordination polymer framework was developed by employing a novel carbodithioate group for the linkage with nickel(II) that extends in three dimensions, which shows enhanced, electrical conductivity (i.e. 10-6 – 10-7 S cm-1) in contrast to traditional carboxylate-based MOFs due to a more delocalized electronic feature of the carbodithioate-nickel cluster. More importantly, its unique electronic properties, especially a long-lived charge-separation state captured by transient-absorption technique, could alleviate the compromise between electrical conductivity and charge separation (resulted from bandgap) of light-harvesting material. We then extend this binding group to chromium(III), as introduced in chapter 6, leading to a paramagnetic 3D coordination polymer with metallic conductivity as opposed to its nickel counterpart.
68

Post-traumatic stress disorder symptoms impacting caregivers of children with CHARGE syndrome

Ferrigno, Matthew A. 06 August 2021 (has links) (PDF)
The current study aimed to focus on Post-Traumatic Stress Disorder (PTSD) symptoms in parents who have a child diagnosed with a rare genetic syndrome called CHARGE Syndrome. While previous studies have investigated related factors to parental PTSD (Reda & Hartshorne, 2008; Wulffaert et al., 2009), this study was one of the first to focus on parental PTSD symptomology and possible traumatic experiences related to CHARGE (e.g., medical complications). Specific concerns related to PTSD addressed in the current study included trauma histories, the number of surgeries a child underwent, and parent stress levels. One hundred and ninety-seven parents completed surveys that met inclusion criteria for the study. Findings indicated that 48% of parents showed signs of PTSD based on reported symptomology. Additionally, higher parent stress levels were found to be contributed to greater symptomology presentation. Overall outcomes of the study demonstrate that PTSD and parent stress levels may affect parents' abilities to adequately provide the needed emotional support and care for their children with CHARGE Syndrome without support. This study paves the way for additional research in this area to focus on the screening and development of treatment resources for parents of children with CHARGE Syndrome. Future directions and limitations were discussed in detail.
69

A Miniature Blast-Gauge Charge Amplifier System

Rieger, James L., Weinhardt, Robert 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Transducers whose outputs are characterized as a charge require signal conditioning to convert the charge produced to a voltage or current for use in instrumentation systems. Blast gauges, in particular, require processing which preserves the transient nature of the data and very fast risetimes, which would otherwise be degraded by long cable runs and parasitic capacitances. A charge amplifier which amplifies and converts a charge to a low-impedance voltage suitable for driving coaxial lines is described, along with theory of operation. Charge amplifiers of the type described are relatively unaffected by temperature and power supply variations, and occupy less than two square inches of printed circuit board space per channel.
70

Theoretical studies of transition metal containing diatomics and DNA electron transfer

唐素明, Tong, So-ming, Glenna. January 2002 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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