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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.
21

Estudo de Sítios de Cromo em Vidros Aluminoboratos de Bário e sua Aplicação na Sensitização da Luminescência do Neodímio / Study of sites of chromium in barium aluminoboratos glasses and its application in the sensitization of the neodymium luminescence.

Luzia Saeko Kanashiro 03 February 1999 (has links)
Amostras de vidros aluminoboratos de bário contendo impureza de cromo, apresentando proporções de íons Cr POT. 3+, Cr POT 5+ e Cr POT. 6+, determinadas pelas condições oxidantes ou redutoras de fusão, foram preparadas e caracterizadas pelas técnicas de absorção óptica (AO), fluorescência e de ressonância paramagnética eletrônica (RPE). As condições redutoras necessárias para favorecer a obtenção de vidros contendo majoritariamente íons de Cr POT. 3+ foram satisfeitas com a adição de 0,6% em peso de Sb IND. 2 O IND. 3. Nos vidros contendo antimônio, a banda 4 ANTIPOT. T IND. 2 do Cr POT. 3+ aparece ligeiramente deslocada para comprimentos de onda maiores e mais alargada, em relação ao vidro contendo apenas cromo como impureza adicional. O parâmetro de Racah B e a intensidade de campo ligante Ll foram determinados, obtendo-se os valores B = 759 cm-1 e = 15800 cm-1 para o vidro com cromo e antimônio e B = 736 cm-1 e = 16150 cm-1 para o vidro contendo apenas a adição de cromo. Foram observadas antirressonâncias de Fano nos espectros de AO, mais definidas nas amostras sem antimônio. Os espectros de RPE indicam que os íons Cr POT. 3+ isolados estão preferencialmente localizados em sítios distorcidos de simetria octaédrica, apresentando uma linha de absorção em g = 5,15, notando-se também a presença de pares de Cr POT 3+ caracterizados por uma componente da linha em g = 2,0. Com a adição de neodímio, os espectros de AO e de RPE do Cr POT. 3- não sofreram alterações, mas o espectro de fluorescência, com o máximo localizado em 776 nm, foi bastante modificado, mostrando uma diminuição da intensidade em regiões do espectro características da absorção do Nd POT. 3+, indicando a ocorrência de um processo de transferência de energia dos íons Cr POT. 3+ para os íons Nd POT. 3+ nos vidros aluminoboratos de bário, à temperatura ambiente. Os espectros de fluorescência e excitação dos vidros duplamente dopados com cromo e neodímio mostraram o efeito de antiressonâncias de Fano, com o deslocamento de Lamb dos vales associados ao neodímio sobre do Cr POT. 3+. / Barium aluminoborate glass samples containing chromium impurities, presenting Cr3- , Cr5- e Cr6+ íon amounts determined by the oxidizing or reducing melting conditions, have been prepared and characterized by Optical Absorption (OA), fluorescence and Electron Paramagnetic Resonance (EPR) techniques. The reducing conditions necessary to obtain glasses having mainly Cr3+ íons were satisfied with the addition of 0.6 wt% of Sb2 O3 to the batch. In glasses containing antimony, the 4T2 band is wider and shifted towards the higher wavelengths in relation to glass containing only chromium as additional impurity. The Racah parameter B and the ligand field intensity L1 were determined, yielding B = 759 cm-1 and L1 = 15800 cm-1 for the chromium- and antimony-doped glass, and B = 736 cm-1 and L1 = 16150 cm-1 for glass containing only chromium impurity. Fano antiresonances were observed in the OA spectra, better defined in the samples without antimony. The RPE spectra show that the Cr3- ions are preferentially located at distorted octahedral sites. An absorption line was observed at g = 5. 15 and it has been noted also the presence of Cr3+ pairs characterized by a line component at g = 2.0. With the addition of neodymium, the OA and EPR spectra of Cr3+ did not change, but the fluorescence spectrum observed at 776 nm was considerably modified, indicating the occurrence of an energy transfer process from Cr3+ to Nd3- íons in barium aluminoborate glasses at room temperature. The fluorescence and excitation spectra of glasses doped with chromium and neodymium have shown the Fano antiresonance effect, with the Lamb shift of the valleys associated to neodymium over the emission bands ofCr3+.
22

Ambientes de coordenação de heteropolioxometalatos de Keggin em xerogeis fotocrômicos analisados por espectroscopia de RMN e RPE em sólidos / Keggin heteropolyoxometalates coordination environments in photochromic xerogels studied by solid state NMR and EPR spectroscopy

Marcos de Oliveira Junior 24 February 2014 (has links)
Neste trabalho, é analisada a estrutura de materiais híbridos contendo poliânions de ácido 12-tungstofosfórico (H3PW12O40, HPW) inseridos em uma matriz de silicatos orgânico-inorgânica (ormosil). Estes materiais apresentam propriedade reversível de fotocromismo na faixa do UV (200-400nm), sendo cogitados como possíveis candidatos para aplicação como dosímetros pessoais UV. A metodologia sol-gel possibilita a obtenção destes compostos por vias relativamente simples e de baixo custo para a combinação dos componentes orgânicos e inorgânicos formadores da matriz ormosil. As propriedades do efeito fotocrômico, como intensidade e tempo de vida, ser alteradas variando-se a concentração e a natureza dos grupos presentes na matriz ormosil. Outras propriedades também podem ser ajustadas, como porosidade, adesão dos filmes, resistência mecânica, homogeneidade e transparência. No entanto uma correlação clara entre o processo de fotocromismo e a estrutura local ao redor do poliânion ainda não foi estabelecida. O objetivo geral da pesquisa é a caracterização estrutural e dinâmica destes compostos, a fim de se avançar no entendimento do processo fotocrômico e na otimização de métodos de preparação para o controle das propriedades fotocrômicas. Resultados preliminares mostram que o ambiente de coordenação do HPW nos ormosils é complexo, envolvendo diversas espécies de prótons, e os níveis de hidratação parecem desempenhar importante papel estrutural. Portanto, o objetivo específico deste trabalho é obter uma descrição da estrutura/dinâmica das espécies no ambiente de coordenação do poliânion, como espécies de hidratação e/ou grupos da matriz ormosil, e da interação entre estas espécies e o HPW. Para tal, foram utilizadas técnicas de ressonância magnética nuclear (RMN) para analisar amostras de composição simplificada, como uma amostra modelo HPW n6H2O e xerogeis contendo tetraetilortosilicato (TEOS) e no máximo dois organosilanos na composição, dentro do conjunto: 3-aminopropiltrietóxisilano (APTS), butironitrilatrietoxisilano (BUT) e 3 glicidoxipropilltrimetóxisilano (GLYMO). Embora a estrutura do HPW n6H2O seja extensamente discutida na literatura, ainda existem questões estruturais a serem discutidas, para as quais as técnicas de RMN podem fornecer importante contribuição. Diferentes tratamentos térmicos sobre o HPW nH2O foram testados para a obtenção do HPW n6H2O, e os resultados de RMN mostram que o controle de atmosfera durante o processo de secagem é determinante para a estrutura final das espécies de hidratação. No caso dos xerogeis, diferentes atmosferas foram testadas durante o preparo, estudando-se o efeito desta variável sobre a estrutura das espécies no ambiente de coordenação do HPW. Adicionalmente, tratamentos térmicos para a secagem das amostras também foram realizados. Após a irradiação das amostras com luz UV é formado um centro paramagnético WV no poliânion, que foi estudado por ressonância paramagnética eletrônica (RPE). A técnica de 31P permitiu avaliar a estrutura no ambiente mais local da molécula de HPW. Utilizando técnicas de 1H RMN, polarização cruzada (CP) {1H}-31P, correlação heteronuclear (HETCOR) {1H}-31P, {1H}-29Si e {1H}-13C, e medidas de tempos de relaxação spin-rede de 1H no sistema rotante (T1&rho;), foi constatado que o ambiente de coordenação do HPW nos xerogeis é basicamente constituído de espécies de hidratação, como H2O, H3O+, H5O2+ e H+(H2O)n, e espécies OH, que provavelmente pertencem a grupos na matriz de ormosil. Os experimentos de RPE permitiram identificar a existência de uma processo termicamente ativado, em que o elétron excitado realiza saltos entre os diferentes sítios WO6. Dois tipos de centros paramagnéticos WO6, ambos com simetria ortorrômbica, foram resolvidos em 20K. Um deles pôde ser atribuído a sítios WO6 interagindo fortemente com H2O, com a elongação da ligação W=O em WO6. Este sítio é dominante para amostras mais hidratadas. Além deste, outro sítio é observado em amostras mais secas, atribuído a centros WO6 interagindo mais fracamente com os H no ambiente do HPW. Estes resultados mostram que as espécies de hidratação desempenham um importante papel no processo de fotocromismo. / The local structure of hybrid organic-inorganic (ormosils) materials based on 12-phosphotungstic acid (H3PW12O40, HPW) was analyzed. These materials have reversible photochromic response in the range of ultraviolet (200 - 400 nm), and may found application in personal UV dosimeters. These ormosils can be prepared in a simple way using the sol-gel method, allowing the possibility of film depositions. It is known that properties such as the intensity of the photochromic response and the life-time in this state can be controlled changing the organic functional groups in the silane precursors. Other general properties can be also adjusted with these organic functionalities, such as film adhesion, mechanical response, homogeneity and transparency. However, the relation between the photochromic response, the chemical species (including water molecules) around the polyanion, and the local structure is still an open problem. The objective of this work was to analyze the effect of the preparation conditions of the ormosils (composition, atmosphere and thermal treatments) on the chemical environment around the polyanion and their possible influence in the photochromic response. The analysis of the interaction between the polyanion and the chemical species in the ormosil network and hydration species was carried out using nuclear magnetic resonance spectroscopy (NMR) in the solid-state for 1H, 31P, 13C, and 29Si. A set of simple photochromic ormosils were considered in this study, prepared with tetraethilorthosilicate (TEOS) and a maximum of two organosilane precursors from the set aminopropyltriethoxysilane (APTS), butyronitriletriethoxysilane (BUT) and 3-Glycidoxypropyltrimethoxysilane (GLYMO). Also, the HPW hexahydrate (HPW 6H2O) was analyzed as a model system to test the response of the NMR technique to the structural and dynamical process known in this crystal. The effects of thermal treatments and atmosphere in the preparation of the hexahydrate were analyzed. New information concerning the H dynamics and the thermal transformations observed in this system was gathered in this study. For the photochromic ormosils, preparations under three different atmospheres (uncontrolled ambient, N2 flow, and Ar glove-box) were carried out, as well thermal treatments to remove loosely bound water. Electronic paramagnetic resonance (EPR) experiments were carried out in UV-irradiated ormosils, were paramagnetic centers in WV, related with the photochromic process, were observed. The chemical environment around the polyanion was probed using the techniques of 1H-NMR, {1H}-31P cross-polarization, heteronuclear correlations {1H}-31P, {1H}-29Sie {1H}-13C, and the measurement of the proton spin-lattice relaxation in the rotating frame (T1&rho;). The results revealed the presence of close hydration species such as H2O, H3O+</sup), H5O2+ and H+(H2O)n, and OH groups from the ormosil network. No evidence of interaction between the polyanion and the organic functionalities was found. In the irradiated samples, the EPR experiments revealed a thermally activated hopping process for the excited unpaired electron between WO6 octahedra. Two kinds of paramagnetic sites at the WO6 octahedra, both with orthorrombic symmetry, were resolved at 20K. One of them corresponds to WO6 strongly interacting with water species, with an elongated W=O bond length. This site is dominant for higher hydrated samples. The other site corresponds to WO6 with a weak interaction with protons in the polyanion environment and is observed in higher amounts in less hydrated samples. These results show that the hydrate species in the polyanion coordination environment plays an important role in the photochromic process.
23

Caracterização físico-química da cerâmica do sítio arqueológico São Paulo II / Physical and chemical characterization of ceramics from archaeological site São Paulo II

Rogério Baria Ribeiro 27 May 2013 (has links)
A arqueometria é uma área consolidada, com ampla utilização de métodos analíticos nucleares destrutivos e não destrutivos para caracterização, proteção e restauração de peças arqueológicas. O presente projeto teve como objetivo estudar a composição química elementar de amostras de fragmentos cerâmicos encontradas no sítio arqueológico São Paulo II localizado na calha do rio Solimões, próximo ao município de Coari na Amazônia Brasileira. Realizou-se a caracterização das amostras pela determinação de Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sb, Sm, Rb, Sc, Ta, Tb, Th, U, Yb and Zn por meio da análise por ativação com nêutrons (NAA). A partir da composição química da cerâmica, foi possível definir o agrupamento de amostras em função da similaridade/dissimilaridade da composição química presente no material cerâmico. O agrupamento foi interpretado por métodos estatísticos multivariados como análise de cluster, análise de componentes principais e análise de discriminante. Foram selecionadas, a partir da formação dos grupos, 7 cerâmicas com o objetivo de elaborar o horizonte temporal do sítio, realizado por termoluminescência (TL) e ressonância paramagnética eletrônica (EPR). A temperatura de queima da cerâmica foi determinada em 6 fragmentos por meio da técnica de EPR. Os resultados apresentados neste trabalho podem contribuir com os estudos arqueológicos sobre a dinâmica da ocupação da Amazônia Central anterior à colonização Brasileira. / Archaeometry is currently a well established field in the archaeological sciences. The nuclear method for analysis of chemical elements is one of the important instruments for the characterization of the archaeological materials and has influences on the preservation and restoration. From the chemical and physical analyses it is possible to infer technical processes in ceramics manufacture and tools used by ancient people. Therefore, it contributes to the typology and to understand the roles of materials available in the archaeological sites, such as clays and lythic sources. Evidently, all the archaeological materials and sites are related to people that lived there a long time ago, and studies, as outlined above, reconstruct at least partially the history of such a population. This project aimed at studying the elementary chemical composition of 70 ceramic fragments samples from São Paulo II archaeological site, located along the Solimões River channel, next to Coari city, in Brazilian Amazon. The characterization of samples was performed by neutron activation analysis (NAA). By the determination of 22 elements in the ceramic fragments ( Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sb, Sm, Rb, Sc, Ta, Tb, Th, U, Yb and Zn), it was possible to define groups of samples regarding the similarity/dissimilarity in elementary chemical composition. For such a task, the multivariate statistical methods employed were cluster analysis (CA), principal component analysis (PCA) and discriminant analysis (DA). Afterwards, seven ceramic fragments have been selected to elaborate the site temporal horizon using thermoluminescence (TL) and electron paramagnetic resonance (EPR) dating results. The EPR technique was also used to find the average firing temperature to produce the ceramics. The results of this research may contribute to the study on the occupation dynamics in the pre-colonial Brazilian Amazon.
24

Ambientes de coordenação de heteropolioxometalatos de Keggin em xerogeis fotocrômicos analisados por espectroscopia de RMN e RPE em sólidos / Keggin heteropolyoxometalates coordination environments in photochromic xerogels studied by solid state NMR and EPR spectroscopy

Oliveira Junior, Marcos de 24 February 2014 (has links)
Neste trabalho, é analisada a estrutura de materiais híbridos contendo poliânions de ácido 12-tungstofosfórico (H3PW12O40, HPW) inseridos em uma matriz de silicatos orgânico-inorgânica (ormosil). Estes materiais apresentam propriedade reversível de fotocromismo na faixa do UV (200-400nm), sendo cogitados como possíveis candidatos para aplicação como dosímetros pessoais UV. A metodologia sol-gel possibilita a obtenção destes compostos por vias relativamente simples e de baixo custo para a combinação dos componentes orgânicos e inorgânicos formadores da matriz ormosil. As propriedades do efeito fotocrômico, como intensidade e tempo de vida, ser alteradas variando-se a concentração e a natureza dos grupos presentes na matriz ormosil. Outras propriedades também podem ser ajustadas, como porosidade, adesão dos filmes, resistência mecânica, homogeneidade e transparência. No entanto uma correlação clara entre o processo de fotocromismo e a estrutura local ao redor do poliânion ainda não foi estabelecida. O objetivo geral da pesquisa é a caracterização estrutural e dinâmica destes compostos, a fim de se avançar no entendimento do processo fotocrômico e na otimização de métodos de preparação para o controle das propriedades fotocrômicas. Resultados preliminares mostram que o ambiente de coordenação do HPW nos ormosils é complexo, envolvendo diversas espécies de prótons, e os níveis de hidratação parecem desempenhar importante papel estrutural. Portanto, o objetivo específico deste trabalho é obter uma descrição da estrutura/dinâmica das espécies no ambiente de coordenação do poliânion, como espécies de hidratação e/ou grupos da matriz ormosil, e da interação entre estas espécies e o HPW. Para tal, foram utilizadas técnicas de ressonância magnética nuclear (RMN) para analisar amostras de composição simplificada, como uma amostra modelo HPW n6H2O e xerogeis contendo tetraetilortosilicato (TEOS) e no máximo dois organosilanos na composição, dentro do conjunto: 3-aminopropiltrietóxisilano (APTS), butironitrilatrietoxisilano (BUT) e 3 glicidoxipropilltrimetóxisilano (GLYMO). Embora a estrutura do HPW n6H2O seja extensamente discutida na literatura, ainda existem questões estruturais a serem discutidas, para as quais as técnicas de RMN podem fornecer importante contribuição. Diferentes tratamentos térmicos sobre o HPW nH2O foram testados para a obtenção do HPW n6H2O, e os resultados de RMN mostram que o controle de atmosfera durante o processo de secagem é determinante para a estrutura final das espécies de hidratação. No caso dos xerogeis, diferentes atmosferas foram testadas durante o preparo, estudando-se o efeito desta variável sobre a estrutura das espécies no ambiente de coordenação do HPW. Adicionalmente, tratamentos térmicos para a secagem das amostras também foram realizados. Após a irradiação das amostras com luz UV é formado um centro paramagnético WV no poliânion, que foi estudado por ressonância paramagnética eletrônica (RPE). A técnica de 31P permitiu avaliar a estrutura no ambiente mais local da molécula de HPW. Utilizando técnicas de 1H RMN, polarização cruzada (CP) {1H}-31P, correlação heteronuclear (HETCOR) {1H}-31P, {1H}-29Si e {1H}-13C, e medidas de tempos de relaxação spin-rede de 1H no sistema rotante (T1&rho;), foi constatado que o ambiente de coordenação do HPW nos xerogeis é basicamente constituído de espécies de hidratação, como H2O, H3O+, H5O2+ e H+(H2O)n, e espécies OH, que provavelmente pertencem a grupos na matriz de ormosil. Os experimentos de RPE permitiram identificar a existência de uma processo termicamente ativado, em que o elétron excitado realiza saltos entre os diferentes sítios WO6. Dois tipos de centros paramagnéticos WO6, ambos com simetria ortorrômbica, foram resolvidos em 20K. Um deles pôde ser atribuído a sítios WO6 interagindo fortemente com H2O, com a elongação da ligação W=O em WO6. Este sítio é dominante para amostras mais hidratadas. Além deste, outro sítio é observado em amostras mais secas, atribuído a centros WO6 interagindo mais fracamente com os H no ambiente do HPW. Estes resultados mostram que as espécies de hidratação desempenham um importante papel no processo de fotocromismo. / The local structure of hybrid organic-inorganic (ormosils) materials based on 12-phosphotungstic acid (H3PW12O40, HPW) was analyzed. These materials have reversible photochromic response in the range of ultraviolet (200 - 400 nm), and may found application in personal UV dosimeters. These ormosils can be prepared in a simple way using the sol-gel method, allowing the possibility of film depositions. It is known that properties such as the intensity of the photochromic response and the life-time in this state can be controlled changing the organic functional groups in the silane precursors. Other general properties can be also adjusted with these organic functionalities, such as film adhesion, mechanical response, homogeneity and transparency. However, the relation between the photochromic response, the chemical species (including water molecules) around the polyanion, and the local structure is still an open problem. The objective of this work was to analyze the effect of the preparation conditions of the ormosils (composition, atmosphere and thermal treatments) on the chemical environment around the polyanion and their possible influence in the photochromic response. The analysis of the interaction between the polyanion and the chemical species in the ormosil network and hydration species was carried out using nuclear magnetic resonance spectroscopy (NMR) in the solid-state for 1H, 31P, 13C, and 29Si. A set of simple photochromic ormosils were considered in this study, prepared with tetraethilorthosilicate (TEOS) and a maximum of two organosilane precursors from the set aminopropyltriethoxysilane (APTS), butyronitriletriethoxysilane (BUT) and 3-Glycidoxypropyltrimethoxysilane (GLYMO). Also, the HPW hexahydrate (HPW 6H2O) was analyzed as a model system to test the response of the NMR technique to the structural and dynamical process known in this crystal. The effects of thermal treatments and atmosphere in the preparation of the hexahydrate were analyzed. New information concerning the H dynamics and the thermal transformations observed in this system was gathered in this study. For the photochromic ormosils, preparations under three different atmospheres (uncontrolled ambient, N2 flow, and Ar glove-box) were carried out, as well thermal treatments to remove loosely bound water. Electronic paramagnetic resonance (EPR) experiments were carried out in UV-irradiated ormosils, were paramagnetic centers in WV, related with the photochromic process, were observed. The chemical environment around the polyanion was probed using the techniques of 1H-NMR, {1H}-31P cross-polarization, heteronuclear correlations {1H}-31P, {1H}-29Sie {1H}-13C, and the measurement of the proton spin-lattice relaxation in the rotating frame (T1&rho;). The results revealed the presence of close hydration species such as H2O, H3O+</sup), H5O2+ and H+(H2O)n, and OH groups from the ormosil network. No evidence of interaction between the polyanion and the organic functionalities was found. In the irradiated samples, the EPR experiments revealed a thermally activated hopping process for the excited unpaired electron between WO6 octahedra. Two kinds of paramagnetic sites at the WO6 octahedra, both with orthorrombic symmetry, were resolved at 20K. One of them corresponds to WO6 strongly interacting with water species, with an elongated W=O bond length. This site is dominant for higher hydrated samples. The other site corresponds to WO6 with a weak interaction with protons in the polyanion environment and is observed in higher amounts in less hydrated samples. These results show that the hydrate species in the polyanion coordination environment plays an important role in the photochromic process.
25

The Relationship between Pass Completion Percentage and Perceived Player Workload in NCAA Division I Women's Soccer

Passingham, Alexa L 01 December 2015 (has links)
In an attempt to demonstrate the interconnecting nature of the pillars of sport (Hacker, 2000) this thesis explores the relationship between physical, psychological and technical variables. Five National Collegiate Athletic Association (NCAA) Division I Women’s Soccer players were analyzed in four conference matches. The athlete's rate of perceived exertion (RPE) values were correlated to pass completion percentages (PC%) to investigate the potential effect that psychological satisfaction or dissatisfaction of technical performance has on perceived exertion ratings. PlayerLoadTM (PL) values, gathered through the utilization of a Catapult Minimax S4 GPS device (miniMax-10 Hz, Catapult Innovations, Melbourne, Australia), were used as a measure of actual workload in order to determine the accuracy of perceived exertion ratings. Results exhibited a trivial correlation (r = 0.028) and large variability (R2 = 0.00077) between RPE and PC% in comparison to PL and PC% (r = 0.50; R2 = 0.2502). The results indicate that an athlete's PC% does not correspond to how physically demanding they perceived a match to be. However, it is possible that performance variables may influence the RPE ratings a player provides.
26

Étude de l'environnement et des propriétés optiques des ions Ti3+ formés sous irradiation ionisante dans les verres d'oxyde

Lombard, Pierre 19 October 2009 (has links) (PDF)
Nous avons étudié par spectroscopie de Résonance Paramagnétique Électronique (RPE), par simulation de spectre RPE, par spectroscopie Raman et par photoluminescence les ions Ti3+ formés par irradiation aux β de 3,37 x 10^5 à 1,68 x 10^9 Gy dans les verres SiO2 - Na2O - TiO2 et SiO2 - Al2O3 - B2O3 - Na2O - TiO2. Nous montrons que ces ions existent dans les verres silicatés dans trois sites différents correspondant à trois environnements différents : [VI]Ti3+, [V]Ti3+ sous forme de pyramide à base carrée et peut être sous forme de bi-pyramide. Il existe de même trois sites des ions Ti3+ dans les verres alumino-borosilicatés et le site des ions [VI]Ti3+ est commun aux deux classes de verres. L'étude de l'évolution des proportions d'ions Ti3+ dans chacun des sites ainsi que l'étude des paramètres RPE des sites montre que leur existence est déterminée par la dose intégrée et la valeur du rapport [Na]/[Ti] que nous redéfinissons dans le cas des verres alumino-borosilicatés. Enfin, sous une excitation à 266 nm nous observons à température ambiante une bande d'émission à 500 nm attribuée aux ions Ti4+. Sous une excitation à 532 nm, nous observons une bande d'émission à 590 nm avec des temps de vie courts d'une centaine de ns que nous attribuons soit aux ions Ti3+ soit à des défauts formés près des ions Ti4+. Dans l'ensemble, cette étude montre donc qu'il est possible de contrôler par la chimie et la dose intégrée l'environnement des ions Ti3+ et donc les propriétés d'émission de cet ion dans un verre.
27

Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion

VILLANEUVA, MARIA BEATRIZ G., TAKEUCHI, YASUHIRO, ANDO, SHOKO, ICHIHARA, GAKU, SHIBATA, EIJI, KAMIJIMA, MICHIHIRO, HIRUTA, SHUICHI, SHIMAOKA, MIDORI, ONO, YUICHIRO, HATTORI, YOJI January 1996 (has links)
名古屋大学博士学位論文 学位の種類 : 博士(医学)(論文) 学位授与年月日:平成8年7月12日 服部洋兒氏の博士論文として提出された
28

LYSOSOMAL DESTABILIZATION IN RETINAL PIGMENT EPITHELIAL CELLS ACTIVATES THE NLRP3 INFLAMMASOME AND INDUCES IL-1β SECRETION

Tseng, Wen Allen 06 June 2014 (has links)
Age-related macular degeneration (AMD) is a leading cause of visual impairment and blindness, affecting over 30 million people worldwide. It is characterized by the appearance of insoluble deposits known as drusen in the outer retina, between the retinal pigment epithelium (RPE) and Bruch's membrane. Drusen are heterogeneously composed of many compounds, including cholesterol, amyloid-β, and complement proteins. AMD also involves the accumulation of pigments collectively termed lipofuscin in RPE lysosomes. The underlying causes of AMD are unknown, but studies have implicated inflammatory processes in its pathogenesis.
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An examination of the training loads within elite professional football

Malone, James J. January 2014 (has links)
The popularity of soccer throughout the world has led to the demand for a scientific approach to the preparation of players for competitive matches. Although previous researchers have attempted to understand the training demands undertaken by soccer players, limited information is known regarding the structure of training in soccer. At present research has focused on the frequency and duration of soccer training without using both objective and subjective measures of training load to systematically evaluate training practices in elite teams. Little is also known regarding the periodisation strategies employed by elite soccer teams across a competitive season and whether they follow traditional models of periodisation. With this in mind, the primary aim of this thesis is to therefore characterise the current training periodisation practices that exist in elite soccer using applied methods of training load assessment. The aim of the first study (Chapter 3) was to evaluate the use of Global Positioning Devices (GPS) for the measurement of soccer-specific activities to provide objective data for training load assessment. Findings from this study were applied to study 3 (Chapter 5) of the thesis. Firstly, a soccer-specific movement course was designed based on the movements exhibited by an elite soccer player during a competitive match using a multi-camera tracking system (ProZone®). Two moderately trained males performed 10 bouts of the soccer-specific track following familiarisation and a 10 minute standardised warm up. Both subjects wore two 10Hz GPS units inside a custom-made vest during all bouts of the track to determine both reliability and inter-unit reliability of the GPS devices. Data analysis revealed the reliability of the GPS devices was good for distance covered at lower velocities (0 – 4 m/s; CV% = 0.6 – 3.6%). However when the velocity of movement increased (> 4 m/s), the reliability of the units decreased (mean change from 13.8 to 33.6 CV%). Both total distance (mean CV% = 1.1%) and max speed (mean CV% = 2.7%) were both found to be highly reliable variables. However the devices demonstrated high levels of inter-unit reliability error due to an increase in systematic error with random distribution of data points between both devices for all variables measured. The data suggested that 10Hz GPS devices are reliable for the measurement of lower velocity (0 – 4 m/s) running. However, care must be taken when analysing data in higher velocity bands (> 4 m/s) due to the high ii error rates observed. The high inter-unit reliability error also suggests that 10Hz GPS devices cannot be used interchangeably between players in order to minimise the associated error. The aim of the second study (Chapter 4) was to quantify the reliability and validity of a portable vertical jump assessment tool (Optojump®) for use in the applied setting. Vertical jump assessment was utilised as a measurement tool to analyse the effect of training load on the neuromuscular system that was evaluated in study 4 (Chapter 6) of the thesis. Eleven healthy male subjects were familiarised to perform four separate common types of vertical jump test: countermovement with arm swing (CMJ-W), countermovement without arm swing (CMJ-WO), squat jump (SJ) and drop jump (DJ). Contact time, flight time and jump height were selected as variables for the study. For reliability assessment, all subjects performed 3 efforts of each jump type across 5 identical testing sessions (separated by minimum of 2 days). For validity assessment, subjects were asked to perform the same jump modalities as the previous investigation on one occasion while data was simultaneously collected from both a force plate (criterion instrument) and the Optojump photocells. The data revealed the Optojump device was highly reliable for the assessment of jump flight and height for CMJ-W, CMJ-WO, SJ and DJ (all CV% = 3.2 and 5.6%). However reliability of the device was reduced for the measurement of contact time with the DJ (CV% = 13.9%). Validity data revealed that all jump types and variables were highly valid in comparison to the force plate criterion measure (SEE% = < 1%, Pearsons correlation = r > 0.99). This study revealed that the Optojump device is highly reliable and valid for all jump types and variables, with the exception of contact time for DJ. Therefore the Optojump system may be used with confidence to detect within-group changes in applied assessments of vertical jump performance. Due to the high cost and lack of portability of laboratory-based force plates, the Optojump system is a viable alternative for accurate jump measurement and neuromuscular assessment. The CMJ-WO jump assessment was chosen for study 4 for comparison with previous research. The aim of the third study (Chapter 5) was to quantify the periodisation strategies employed by an elite professional soccer team throughout a competitive season. Training load data was collected from 37 elite outfield soccer players at one professional English soccer team over a 45 week period during the 2011-2012 domestic season. All players wore iii global positioning system (GPS) devices, heart rate (HR) belts and were asked to provide a rating of perceived exertion (RPE) for each training session to generate training load data. Players were assigned to one of 5 positional groups: central defender (CD), wide defender (WD), central midfielder (CM), wide midfielder (WM) and attacker (AT). The data was separated into the pre-season (6 weeks duration) and in-season (39 weeks duration) phases in order to investigate specific training periods recognised within the annual plan. The pre-season phase was further separated into weekly blocks for analysis of the structure employed in each specific microcycle. The in-season phase was divided into 6 x 6 week blocks for analysis of mesocycle structure. Within the in-season data, three separate microcycles (weeks 7, 24 and 39) were selected consisting of the same weekly training schedules to determine whether differences in microcycle training load pattern existed. In addition, the training data within a given microcycle was analysed to investigate the loading patterns in relation to number of days away from the competitive match fixture. Linear mixed modelling analysis revealed significant differences for total distance and average HR (P < 0.05) between period 1 with periods 3 and 6 during training mesocycles. However no differences were found for the remaining training variables during both pre-season and in-season microcycles (P > 0.05). Training load variables were significantly reduced on match day (MD) -1 (P < 0.05) but remained similar across MD-2, MD-3 and MD-5 (P > 0.05) during in-season microcycles. CM players generally covered the most total distance compared to other positions. Defenders reported higher internal load values (average HR and RPE) compared to attackers during in-season training phases but such differences were not evident during pre-season. This study revealed that training load doesn’t appear to be systematically periodised across a competitive season in an elite soccer team. This may have practical implications for training planning, as monotonous training load prescription may lead to maladaptation in soccer players during a competitive season. This was the first study to systematically evaluate periodisation strategies in an elite soccer team, but further work is required to determine such practices at different soccer teams. The aim of the fourth study (Chapter 6) was to determine the neuromuscular response to a microcycle of soccer training in elite soccer players using vertical jump assessment via the Optojump device. Nine elite level youth soccer players from an U18 soccer academy team were recruited for the study. The players underwent four separate on-field soccer training sessions following familiarisation of all testing procedures.
30

A??o da cafe?na sobre o rendimento esportivo de ciclistas em condi??es de calor e umidade

Ferreira, Gard?nia Maria Holanda 10 December 2004 (has links)
Made available in DSpace on 2014-12-17T14:13:59Z (GMT). No. of bitstreams: 1 GardeniaMHF.pdf: 1889124 bytes, checksum: 521dae16063d838bbca29f457e622890 (MD5) Previous issue date: 2004-12-10 / Objetivo: Verificar a a??o da cafe?na no tempo de rendimento, a taxa de esfor?o percebido (RPE), os n?veis plasm?ticos de glicose, s?dio e pot?ssio, a temperatura timp?nica (Tt), o peso corporal (PC), freq??ncia card?aca (FC) e concentra??o urin?ria da cafe?na com a ingest?o de doses de 5 e 9 mg/kg de cafe?na e placebo, em provas cicl?sticas sob condi??es de alto risco t?rmico. M?todos: Foram estudados 8 ciclistas treinados e aclimatizados em 3 provas de 45 km utilizando o modelo experimental e duplo-cego com randomiza??o intra-sujeitos. Resultados: N?o foram observadas diferen?as significativas entre as vari?veis avaliadas, entretanto o tempo de rendimento e a RPE foram menores com as doses de 5 e 9 mg/kg de cafe?na que com a dose placebo. Conclus?es: Estes dados indicam que as condi??es de calor e umidade podem ser suficientes para mascarar o benef?cio ergog?nico da cafe?na, entretanto deve-se considerar que a cafe?na pode exercer influencia sobre a percep??o subjetiva de esfor?o podendo levar ? redu??o dos sinais de fadiga durante o exerc?cio e conseq?ente melhora do desempenho esportivo

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