Uma nova metodologia para a medida absoluta da fração efetiva de nêutrons atrasados βeff, baseada em técnicas de análise de ruído microscópico e no modelo de Duas- Regiões, foi desenvolvida no reator IPEN/MB-01. Diferentemente das demais técnicas, tais como o Método de Bennet Modificado, o Método do Número de Nelson e o Método da fonte de 252Cf, a principal vantagem da metodologia proposta é a obtenção de βeff de um modo puramente experimental, sem a necessidade de quaisquer outros parâmetros, sejam estes calculados ou provenientes de outros experimentos. Com a finalidade de validar este novo método, uma série de experimentos Rossi-α e Feynman-α foram realizados no reator IPEN/MB-01. De acordo com a metodologia proposta, βeff foi estimado com uma incerteza de 0.67%, a qual atende aos requisitos de precisão almejados. Além disso, o tempo de geração de nêutrons prontos , dentre outros parâmetros, também foi obtido experimentalmente via esta metodologia. Em geral, os parâmetros medidos estão em acordo com resultados provenientes de experimentos de análise de ruído macroscópico. Nas comparações teoria-experimento, os valores de βeff medidos neste trabalho mostram que a biblioteca JENDL3.3 apresenta a melhor performance (dentro de 1%). Esta concordância justifica a redução no yield de fissão do 235U proposta por Sakurai e Okajima. / A new method for absolute measurement of the effective delayed neutron fraction, βeff , based on microscopic noise experiments and the Two-Region Model was developed at the IPEN/MB-01 Research Reactor facility. In contrast with other techniques like the Modified Bennet Method, Nelson-Number Method and 252Cf-Source Method, the main advantage of this new methodology is to obtain the effective delayed neutron parameters in a purely experimental way, eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-α and Feynman-α experiments for validation of this method were performed at the IPEN/MB-01 facility, and adopting the present approach, βeff was measured with a 0.67% uncertainty. In addition, the prompt neutron generation time, , and other parameters were also obtained in an absolute experimental way. In general, the final results agree well with values from frequency analysis experiments. The theory-experiment comparison reveals that JENDL-3.3 shows deviation for βeff lower than 1% which meets the desired accuracy for the theoretical determination of this parameter. This work supports the reduction of the 235U thermal yield as proposed by Okajima and Sakurai.

A trama de magmas graníticos alojados na crosta intermediária e superior pode-se originar pela ação de forças de corpo (ascensionais, convectivas) e/ou tectônicas. Diferentes mecanismos podem concorrer para a formação de tramas, embora a interação entre a deformação magmática e a tectônica regional seja um dos mecanismos fundamentais, notadamente nos granitos alojados em faixas orogênicas. No Domínio Apiaí da Faixa Ribeira (SP - PR), os batólitos graníticos alongados têm sido historicamente classificados como sintectônicos, ou seja, colocados durante o desenvolvimento de um arco magmático continental neoproterozóico. Os plútons menores, de forma circular a ovalada, geralmente discordantes e com típica coloração avermelhada, são considerados pós-tectônicos ou alojados após a colisão continental entre os diferentes blocos litosféricos que formaram a Faixa Ribeira. Essa classificação esquemática tem sido baseada em geoquímica e geocronologia dos granitos. Este trabalho identificou e mapeou a trama interna dos plútons sin-tectônicos (Ribeirão Branco) e pós-tectônicos (Capão Bonito e Sguário) utilizando a anisotropia de suscetibilidade magnética (ASM), de forma a inserí-los propriamente nos modelos de classificação tectônica, cujas premissas básicas são de natureza estrutural. Os granitos porfiríticos (Ribeirão Branco e Itaóca) possuem uma elevada suscetibilidade magnética (k 10-2 SI), a qual é menor (k 5 x 10-3 SI) nos granitos vermelhos (Capão Bonito e Sguário). A suscetibilidade dos granitos porfiríticos é proveniente de óxidos ferromagnéticos, notadamente magnetita pobre em Ti, que encontra-se frequentemente associada com titanita, biotita e anfibólio. Nos granitos vermelhos a suscetibilidade é gerada por magnetita, variavelmente oxidada (maghemita) e Ti-hematita (hemo-ilmenita), havendo também significativa contribuição da fração paramagnética (biotita cloritizada) à suscetibilidade total nas rochas, quando k < 10-3 SI. O grau de anisotropia magnética (P) tanto nos granitos porfiríticos como nos vermelhos é variável, porém tipicamente maior nos porfiríticos (P = 1,14, dp. 0,08), se comparado aos vermelhos (P = 1,07, dp. 0,05). A maior anisotropia de suscetibilidade no plúton Ribeirão Branco é atribuída a uma incipiente foliação detectada em vários setores do granito, que contrasta com a microestrutura aparentemente isótropa dos granitos vermelhos. O estudo da trama de silicatos no granito porfirítico Itaóca e no granito Capão Bonito mostrou que os eixos principais de anisotropia de suscetibilidade magnética e da orientação preferencial de forma (OPF) de feldspato e de biotita, são correspondentes, porém, comumente oblíquos. Essa obliquidade entre eixos é atribuída às características físicas próprias (forma, tamanho e anisotropia) dos minerais marcadores da trama. O estudo combinado da ASM e da OPF revelou ainda que P tende a crescer com a intensidade da orientação preferencial de silicatos, o que permitiu identificar os domínios de maior deformação magmática e correlacioná-los com a estrutura regional. A trama magnética do granito Ribeirão Branco organiza-se em coerência com uma tectônica regional transcorrente sinistral. Na margem ocidental deste granito, contudo, a orientação da trama é diferente do restante do maciço, tendo sido aparentemente afetada pela intrusão do granito Sguário. A trama magnética do Ribeirão Branco contrasta com a do plúton Itaóca, este último exibindo um padrão concêntrico que antecedeu ao desenvolvimento da deformação transcorrente regional. Zircões do Itaóca forneceram uma idade U-Pb (SHRIMP) concordante de 623 ± 10 Ma, atribuída à cristalização deste plúton. Dados da literatura indicam que o granito Capão Bonito é aproximadamente 15 Ma mais jovem que os batólitos de granito porfirítico. O Capão Bonito, entretanto, apresenta uma trama muito bem organizada, típica de intrusões sin-tectônicas, destacando-se excelente alinhamento da lineação magnética. No granito Sguário, o arranjo da trama é tipicamente helicoidal e, junto com a estrutura do Capão Bonito, podem ter sido organizadas em resposta a uma deformação transcorrente E-W destral. Este evento tardio estaria associado à reativação da zona de cisalhamento Ribeira, que afetou a borda sul do granito Itaóca e que contém uma componente extensional. A deformação transtensiva E-W, que favoreceu a injeção dos granitos vermelhos no Domínio Apiaí, sucederia a um evento tectonomagmático principal, que teria sido responsável pela colocação e deformação dos batólitos de granito porfirítico. A intrusão dos grandes corpos graníticos ocorreu em torno de 615 Ma e foi relacionada à convergência crustal e estiramento subparalelo à Faixa Ribeira, com a deformação localizada notadamente nas estruturas transcorrentes de direção NE-SW. / The fabric of granitic magmas emplaced in the middle and upper crustal levels can be caused by the stress action during the ascension and convection of plutons and/or tectonic strain. Several mechanisms can contribute for the previous thing, nevertheless the interaction between the distortions and tectonic is the domineering one, principally in granites located in orogenic belts. In the Apiaí domain of the Ribeira belt (SP-PR) the elongated granitic batholiths have been historically classified like syn-tectonic and them was emplaced during the development of a neoproterozoic continental magmatic arch. Small Plutons with subcircular to oval forms generally discordant with regard to the disposition of the regional structures and that in turn possess feldspars of reddish typical colour, had been considered pos-tectonic, and therefore, emplaced after the collision that joined the different litho-tectonic units that constitute the Ribeira orogenic belt. This schematic classification of these granites relicts on geochemistry and geochronology data. In this study was identified and recorded in map the internal fabric of the syn-tectonic Ribeirão Branco granite and of the pos-tectonic Capão Bonito and Sguário granites using the anisotropy of magnetic susceptibility (AMS) with the aim of inserting them appropriately in the models of tectonic classification whose basic premises are of structural nature. The porphyritic Ribeirão Branco and Itaóca granites have a high magnetic susceptibility (k = 10-2 SI), which is minor than (k = 5 x 10-3 SI) in the red granites (Capão Bonito, Sguário). In the first ones the poor Ti magnetite is the main source of susceptibility, commonly associated to titanite, biotite and amphibole. In the red granites, the susceptibility is provided by magnetite variability rusty (maghemite) and Ti - hematite (hemo-ilmenite), in addition to the significant contribution of biotite altered by hydrothermal processes. The grade of anisotropy rise (P) in the porphyritic granites (P = 1,14 SD. 0,08) and this is bigger than in the red ones (P = 1,07, SD. 0,05). In the Ribeirão Branco pluton, the high value of P is attributed to an incipient foliation detected in several sectors, which contrasts with the microstructure seemingly isotropic of the red granites. The study of the fabrics of silicates in the porphyritic granites Ribeirão Branco and Itaóca revealed that the orientations of the main axes of AMS and of shape preferred orientation (SPO) of feldspar and mafic silicates (biotite + amphibole) are congruent, nevertheless some obliquities occur. Those obliquities are attributed to the influence of the proper characteristics (form, size, anisotropy) of the marker minerals of the respective sub fabrics. In the same way, the above-mentioned study of silicates fabric demonstrated that P tends to grow up with the intensity of the SPO of silicates, which allowed to identify domains with major magmatic distortion into de granitic bodies and to correlate them with the regional structure. In general, the magnetic fabric of the Ribeirão Branco granite is organized coherently with the tectonic regional sinestral strike-slip shear zones; nevertheless, in the western sector the orientation of the magnetic fabric was likely modified by the accommodation of the Sguário granite. In the Itaóca granite, the organization of the magnetic fabric is different if compared with fabrics of the previous pluton. In Itaóca granite was recorded a fabric with a concentric organization in 623 ± 10Ma. (MSWD 0,31), according to the concordant U-Pb (SHRIMP) age in zircons obtained for the crystallization of the granite, that seems to be occurred before the strain related with the activation of the regional strike-slip shear zones. Geochronology data of the literature indicates that the Capão Bonito granite is approximately 15 Ma. younger than the batholiths of porphyritic granite. The Capão Bonito granite has an organized fabric typical of syn-tectonic intrusions that has an excellent alignment of the magnetic lineation. In the granite Sguário, the fabric has a spiral organization, in the same way as recorded in Capão Bonito, like response to a strain associated with to a small strike-slip shear zone with W-E direction. This event would be related to the reactivation of the Ribeira strike-slip shear zone, which affected the south sector of the Itaóca granite, with the participation of an extensional component. The W-E transtensive deformation that favoured the injection of the red granites in the Apiaí Domain likely was subsequent to a main tetonomagmatic event and this should have been the responsible by the emplacement and strain in the porphyritic granites. The intrusion of the big granitic bodies ~ 615 Ma. and could be it related to the convergence between crustal blocks and to the consequent stretching sub parallel of the Ribeira belt, in which the distortion was located remarkably in the strike-slip shear zones with NE-SW direction.

As interessantes propriedades eletrônicas, mecânicas e óticas dos materiais orgânicos conjugados fizeram emergir diversas aplicações tecnológicas e comerciais em dispositivos baseados nesses materiais, tais como sensores, memórias, células solares e diodos emissores de luz poliméricos (LEDs). Neste sentido, o tema central desta tese é o estudo das propriedades elétricas e morfológicas e os mecanismos de transporte eletrônico de cargas no PEDOT:PSS, uma blenda polimérica que consiste de um policátion condutivo, o poli(3,4- etilenodioxitiofeno) (PEDOT) e do poliânion poli(estirenosulfonado) (PSS). PEDOT:PSS é amplamente usado como material de eletrodo em aplicações na área de eletrônica plástica, como mencionado anteriormente. Apesar da condutividade elétrica dos filmes finos de PEDOT:PSS possa variar várias ordens de grandeza, dependendo do método pela qual é processado e transformado em filme fino, as razões para este comportamento é essencialmente desconhecido. Esta tese descreve um estudo detalhado do transporte eletrônico de cargas anisotrópico e sua correlação com a morfologia, as condições e as dimensões da separação de fase entre os dois materiais, PEDOT e PSS. Antes de abordar as propriedades do PEDOT:PSS, uma camada de filme fino inorgânica usada para aumentar o tempo de vida de dispositivos orgânicos é descrita no Capítulo 2. Um importante mecanismo de degradação em LEDs poliméricos é a fotooxidação da camada ativa. Assim, isolar a camada ativa da água, oxigênio e luz, torna-se crucial para o aumento do tempo de vida. Um sistema de deposição química a partir da fase de vapor estimulada por plasma (PECVD) é usado para depositar filmes finos de nitreto de carbono em baixas temperaturas, menores que 100 °C, sobre PLEDs com a intenção de aumentar o tempo de vida destes dipositivos e diminuir a fotodegradação do poli[2-metoxi-5- (2-etil-hexiloxi)-p-fenileno vinileno] (MEH-PPV) em ambiente atmosférico. O filme fino de nitreto de carbono possui as características de um material que pode bloquear a umidade e que tem espessura e flexibilidade adequados para a nova geração de PLEDs flexíveis. As características dos filmes finos de nitreto de carbono e MEH-PPV foram investigadas usando-se técnicas de espectroscopia ótica, com particular ênfase no processo de degradação do MEHPPV sob iluminação. Os resultados mostraram que o filme fino de nitreto de carbono protege o filme polimérico e diminui consideravelmente a fotooxidação. Para avaliar o efeito do encapsulamento em dispositivos reais, LEDs poliméricos foram fabricados e pelas curvas de corrente-tensão um aumento no tempo de vida é confirmado quando a camada de nitreto de carbono é presente. O tempo de vida desejado, maior que 10.000 horas, para aplicações comerciais não foi atingido, entretanto, o encapsulamento pode ser melhorado otimizando as propriedades da camada de nitreto de carbono e combinando-as com camadas de outros materiais orgânicos e inorgânicos. Os capítulos seguintes deste trabalho aborda os estudos realizados com o PEDOT:PSS, uma vez que é amplamente usado em eletrônica orgânica, mas relativamente tem recebido pouca atenção com respeito ao transporte eletrônico de cargas, bem como sua correlação com a morfologia. No Capítulo 3, experimentos com microscopia de varredura por sonda (SPM, Scanning Probe Microscopy) e medidas de condutividade macroscópica são utilizados para estudar e obter um modelo 3D morfológico completo que explica, qualitativamente, a condutividade anisotrópica observada nos filmes finos de PEDOT:PSS depositados pela técnica de spin coating. Imagens topográficas de microscopia de varredura por tunelamento (STM) e imagens da seção transversal observadas com o microscópio de forca atômica (X-AFM) revelaram que o filme fino polimérico é organizado em camadas horizontais de partículas planas ricas em PEDOT, separadas por lamelas quasi-contínuas de PSS. Na direção vertical, lamelas horizontais do isolante PSS reduzem a condutividade e impõe o transporte eletrônico a ser realizado por saltos em sítios vizinhos próximos (nn-H, nearest-neighbor hopping) nas lamellas de PSS. Na direção lateral, o transporte eletrônico via saltos 3D em sítios a longas distâncias (3D-VRH, variable range hopping) ocorre entre as ilhas ricas em PEDOT que são separadas por barreiras muito mais finas de PSS, causando um aumento da condutividade nesta direção. Esta discussão é estendida ao Capítulo 4 com uma descrição quantitativa do transporte eletrônico de cargas predominantes. Particularmente, é demonstrado que o transporte de cargas via saltos 3D em sítios a longas distâncias ocorre entre ilhas ricas em PEDOT e não entre segmentos isolados de PEDOT ou dopantes na direção lateral, enquanto que na direção vertical o transporte de cargas via saltos em sítios vizinhos próximos ocorre dentro das lamelas do quasi-isolante PSS. Em algumas aplicações, faz-se necessário usar PEDOT:PSS com alta condutividade elétrica. Isso pode ser feito adicionando-se sorbitol à solução aquosa de PEDOT:PSS. Após um tratamento térmico, e dependendo da quantidade de sorbitol adicionado, a condutividade aumenta várias ordens de grandeza e as causas e consequências de tal comportamento foram investigadas neste trabalho. O Capítulo 5 investiga as várias propriedades tecnológicas do PEDOT:PSS altamente condutivo tratado com sorbitol, tais como a própria condutividade, os efeitos dos tratamentos térmicos e exposição à umidade. É observado que o aumento da condutividade elétrica, devido à adição de sorbitol na solução aquosa, é acompanhado por uma melhoria na estabilidade da condutividade elétrica em condições atmosféricas. Surpreendentemente, a condutividade elétrica do PEDOT:PSS, sem tratamento com sorbitol (~ 10-3 S/cm), aumenta mais de uma ordem de grandeza sob ambiente úmido de 30-35 % umidade relativa. Este efeito é atribuido a uma contribuição iônica à condutividade total. Análise Temogravimetrica (TGA), espectrometria de massa com sonda de inserção direta (DIP-MS) e análise calorimétrica diferencialmodulada (MDSC) foram usadas como técnicas adicionais para o entendimento dos estudos deste Capítulo. No Capítulo 6, microscopia de varredura por sonda-Kelvin (SKPM) foi empregada para medir o potencial de superfície dos filmes finos de PEDOT:PSS tratados com diferentes concentrações de sorbitol. Mostra-se que a mudança no potencial de superfície é consistente com uma redução de PSS na superfície do filme fino. Para estudar o transporte eletrônico nos filmes finos de PEDOT:PSS altamente condutivos tratados com sorbitol, o Capítulo 7 usa medidas de temperatura e campo elétrico em função da conduvitidade correlacionados com analises morfológicas realizadas por STM. É observado que o transporte eletrônico por saltos, na direção lateral, muda de 3D-VRH para 1D-VRH quando o PEDOT:PSS é tratado com sorbitol. Esta transição é explicada por uma auto-organização das ilhas ricas em PEDOT em agregados 1D, devido ao tratamento com sorbitol, tornando-se alinhadas em domínios micrométricos, como observado pelas imagens de STM. / Employing the unique mechanical, electronic, and optical properties of the conjugated organic and polymer materials several technological and commercial applications have been developed, such as sensors, memories, solar cells and light-emitting diodes (LEDs). In this respect, the central theme of this thesis is the electrical conductivity and mechanisms of charge transport in PEDOT:PSS, a polymer blend that consists of a conducting poly(3,4-ethylenedioxythiophene) polycation (PEDOT) and a poly(styrenesulfonate) polyanion (PSS). PEDOT:PSS is omnipresent as electrode material in plastic electronics applications mentioned above. Although the conductivity of PEDOT:PSS can vary by several orders of magnitude, depending on the method by which it is processed into a thin film, the reason for this behavior is essentially unknown. This thesis describes a detailed study of the anisotropic charge transport of PEDOT:PSS and its correlation with the morphology, the shape, and the dimension of the phase separation between the two components, PEDOT and PSS. Before addressing the properties of PEDOT:PSS, a new barrier layer is described in Chapter 2 that enhances the lifetime of organic devices. An important degradation mechanism in polymer LEDs is photo-oxidation of the active layer. Hence, isolating the active layer from water and oxygen is crucial to the lifetime. Plasma-enhanced chemical vapor deposition (PECVD) is used to deposit a thin layer of carbon nitride at low deposition temperatures, below 100 °C, on a polymer LED that uses poly[2-methoxy-5-(2´-ethylhexyloxy)-1,4- phenylene vinylene] (MEH-PPV) as active layer. A thin layer of carbon nitride acts as barrier for humidity, but is still sufficiently bendable to be used in flexible polymer LEDs. The characteristics of carbon nitride and MEH-PPV films have been investigated using optical spectroscopy, with particular emphasis on the degradation process of MEH-PPV under illumination. The measurements show that the carbon nitride coating indeed protects the polymer film and diminishes the photo-oxidation considerably. To study the effect of the encapsulation in real devices, polymer LEDs were made and their current-voltage characteristics confirm the enhanced lifetime in the presence of a carbon nitride barrier layer. However, the target, a lifetime of more than 10,000 hours for commercial applications, was not achieved. The remaining chapters of this thesis describe the investigations of PEDOT:PSS. PEDOT:PSS is widely used in organic electronics. So far, relatively little attention has, been paid to the mechanisms of charge transport in this material and the correlation of those properties to the morphology. In Chapter 3, scanning probe microscopy (SPM) and macroscopic conductivity measurements are used to obtain a full 3D morphological model that explains, qualitatively, the observed anisotropic conductivity of spin coated PEDOT:PSS thin films. Topographic scanning probe microscopy (STM) and cross-sectional atomic force microscopy images (X-AFM) reveal that the thin film is organized in horizontal layers of flattened PEDOT-rich particles that are separated by quasi-continuous PSS lamella. In the vertical direction, the horizontal PSS insulator lamellas lead to a reduced conductivity and impose nearest-neighbor hopping (nn-H) transport. In the lateral direction, 3D variable-range hopping (3D-VRH) transport takes place between PEDOT-rich clusters which are separated by much thinner barriers, leading to an enhanced conductivity in this direction. This discussion is extended in Chapter 4, where a quantitative description of the length scales of the predominant transport is obtained. Particularly, it is demonstrated that the hopping process takes place between PEDOT-rich islands and not between single PEDOT segments or dopants in the lateral direction, whilst in the vertical direction the current limiting hopping transport occurs between dilute states inside the quasi-insulating PSS lamellas. By a post-treatment it is possible to modify PEDOT:PSS to raise its conductivity, by orders of magnitude. Typically, the addition of sorbitol to the aqueous dispersion of PEDOT:PSS that is used to deposit thin films via spin coating leads to an enhancement of the conductivity after thermal annealing. The causes and consequences of such behavior were investigated in detail. Chapter 5 describes the various properties of the highly conductive sorbitol-treated PEDOT:PSS, such as the conductivity itself, and the effects of thermal annealing and exposure to moisture. It is found that the conductivity enhancement upon addition of sorbitol is accompanied by a better environmental stability. Surprisingly, the electrical conductivity of PEDOT:PSS thin films without sorbitol treatment is increased by more than one order of magnitude in an environment with more than 30-35 % relative humidity. This effect is attributed to an ionic contribution to the overall conductivity. Thermal gravimetric analysis (TGA), direct insert probe-mass spectrometry (DIP-MS) and modulation differential scanning calorimetry (MDSC) were used as additional tools to demonstrate that, after thermal treatment, the concentration of sorbitol in the final PEDOT:PSS layer is negligibly small. In Chapter 6, scanning Kelvin probe microscopy (SKPM) is employed to measure the surface potential and work function of this PEDOT:PSS films that were deposited from water with different sorbitol concentrations. It is shown that work function of PEDOT:PSS is reduced with increasing sorbitol concentration. This shift can be explained by and is in agreement with- a reduction in the surface enrichment with PSS of the film. To study the charge transport properties of the highly conductive sorbitoltreated PEDOT:PSS films, temperature dependent and electric field dependent measurements are correlated with morphological analysis by STM in Chapter 7. It is found that by sorbitol treatment the hopping transport changes from 3DVRH to 1D-VRH. This transition is explained by a sorbitol-induced selforganization of the PEDOT-rich grains into 1D aggregates that are aligned within micrometer sized domains, as observed in STM images.

Plútons graníticos (Patrimônio Santo Antônio, São Domingos, Ouro Verde e Santa Rita) alojados na porção nordeste da Suíte Intrusiva Cunhaporanga (c. 620-590 Ma) intrudiram metassedimentos pelíticos e carbonáticos de baixo grau metamórfico do Grupo Itaiacoca. Os plútons são isótropos, de coloração cinza a rósea e composição monzo- a sienogranítica, predominando granitóides porfiríticos grossos e, secundariamente, tipos inequigranulares a equigranulares. A cartografia regional mostrou que a foliação das rochas metassedimentares encaixantes mergulha dominantemente para NE e contém uma lineação (interseção, mineral) de direção NNW-SSE. A trama metamórfica das encaixantes assume progressivamente a direção NE-SW conforme se aproxima da zona de cisalhamento transcorrente de Itapirapuã, onde quartzo-milonitos verticalizados exibem uma cinemática sinistral. A trama dos plútons foi estudada pela técnica da anisotropia de suscetibilidade magnética (ASM). Foram amostradas 40 estações (300 espécimes) no granito porfírítico Patrimônio Santo Antônio, 7 estações (48 espécimes) no granito equigranular fino de São Domingos, 9 estações (67 espécimes) no granito inequigranular de Ouro Verde e 14 estações (92 espécimes) no granito porfiritico foliado de Santa Rita. A suscetibilidade magnética média (k) do granito Patrimônio Santo Antônio é da ordem de 23,29 x \'10 POT.-3\' SI, enquanto nos granitos Santa Rita (k = 11,85 mSI), São Domingos (k = 7,43 mSI) e Ouro Verde (k = 7,46 mSI) são menores. Por outro lado, a anisotropia magnética (P = \'k IND.max\'/\'k IND.min\', onde \'k IND.max\' > \'k IND.int\' > \'k IND.min\') é menor em Patrimônio Santo Antônio (P = 1,09 ± 0,04) do que no São Domingos (P = 1,21 ± 0,09), Ouro Verde (P = 1,19 ± 0,07) e Santa Rita (P = 1,23 ± 0,11). Estudos termomagnéticos e de magnetização remanente isotermal mostraram que as propriedades magnéticas dos granitoides são dominadas pela magnetita (pobre em Ti) e, secundariamente, Ti-hematita. Sulfetos de Fe (pirita, calcopirita) ocorrem como acessórios. Os óxidos de Fe estão frequentemente associados à titanita, biotita e anfibólio e suas microestruturas são tipicamente magmáticas, exceto no granito Santa Rita onde a microestrutura apresenta evidência de recristalização pós-magmática. A foliação magnética dos maciços graníticos mergulha suave a moderadamente e, no plúton Patrimônio Santo Antônio, exibe um padrão tipicamente dômico. A lineação magnética subhorizontal orienta-se na direção NNW-SSE paralelamente ao eixo do dobramento regional das rochas metassedimentares encaixantes. Esta característica indica que os granitos são sin-tectônicos a um evento deformacional cujo controle está aparentemente relacionado ao funcionamento das grandes transcorrências regionais de direção NE-SW. A ocorrência de domos graníticos (Patrimônio Santo Antônio) e elipsóides magnéticos dominantemente prolatos (São Domingos) sugerem que a trama NNW teria sido formada por uma tectônica que combina transcorrência e extensão. Uma idade concordante U-Pb (SHRIMP) em zircão de 589 ± 6 Ma, atribuída à cristalização do plúton Patrimônio Santo Antônio, indica que a deformação que afetou o granito no estado magmático bem como suas encaixantes ocorreu nos estágios finais da formação da Suíte Intrusiva Cunhaporanga. / Granite plutons located on the northeast of Cunhaporanga Intrusive Suite (Patrimônio Santo Antônio, Ouro Verde, São Domingos and Santa Rita) are emplaced into low grade metasedimentary rocks (Itaiacoca Group) of the Apiaí Domain (Ribeira Belt). Most of these plutons are isotropic with pinkish to grey colors and their compositions vary from monzogranite to sienogranite. They are usually porphyritic and locally inequigranular and equigranular. Regional mapping revealed that the foliation of the metasedimentary host rocks dips mainly to NE while the lineation (intersection, mineral) strikes in the NNW-SSE direction. The host rocks metamorphic fabric rotates progressively to become parallel to the NE-trending Itapirapuã transcurrent shear zone. Kinematic markers such as elongated quartz grains and mica-fish from quartz-milonites indicate the Itapirapuã shear records a sinistral movement. The fabric of the plutons was studied by anisotropy of magnetic susceptibility (AMS) technique. Forty sites (300 specimens) were sampled at the Patrimônio Santo Antônio granite, 7 sites (48 specimens) at São Domingos, 9 sites (67 specimens) at Ouro Verde and 14 sites (92 specimens) at Santa Rita granite. The mean of magnetic susceptibility (k) is higher in Patrimônio Santo Antônio granite (k = 23,29 x \'10 POT.-3\' SI) and lower in the granites of Santa Rita (k = 11,85 mSI), São Domingos (k = 7,43 mSI) and Ouro Verde (k = 7,46 mSI). In contrast the magnetic anisotropy (P) is lower in the Patrimônio Santo Antônio granite (P = 1,09 ± 0,04) and higher in the granites São Domingos (P = 1,21 ± 0,09), Ouro Verde (P = 1,19 ± 0,07) and Santa Rita (P = 1,23 ± 0,11). Thermomagnetic and Isothermal Remanent Magnetization (IRM) studies show that Ti-poor magnetite is the principal carrier of rock magnetic properties but that includes minor contributions of Ti-hematite. Iron oxides are frequently associated with titanite, biotite and amphibole. Microstructures are typically magmatic, except for Santa Rita granite which shows post-magmatic recrystallized microstructures. The magnetic foliation of granitic plutons dips smooth to moderately and for the Patrimônio Santo Antônio body it exhibits a typical dome pattern. The subhorizontal magnetic lineation strikes NNW-SSE parallel to regional folding axe of the metasedimentary rocks. This feature shows that the granites are syntectonic to a deformation event apparently connected to NE-trending transcurrent shears. The occurrence of a foliation dome in the Patrimônio Santo Antônio pluton and prolate magnetic ellipsoids in São Domingos pluton suggest that the NNW-trending structures includes, besides a strike-slip shear fabric, a component of extension that probably assisted the emplacement of the plutons. A U-Pb (SHRIMP) determination in the Patrimônio Santo Antônio zircons have produced a concordia age of 589 ± 6 Ma attributed to the crystallization of the granite. These results indicate that in the latest stages of the development of the Cunhaporanga Intrusive Suite the Apiaí Domain was submitted to a regional strain field recording transcurrent simple shear and extension.

Cette thèse est consacrée à l’étude théorique et numérique de plusieurs équations aux dérivées partielles non linéaires qui apparaissent dans la modélisation de la séparation de phase et des micro-systèmes électro-mécaniques (MSEM). Dans la première partie, nous étudions des modèles d’ordre élevé en séparation de phase pour lesquels nous obtenons le caractère bien posé et la dissipativité, ainsi que l’existence de l’attracteur global et, dans certains cas, des simulations numériques. De manière plus précise, nous considérons dans cette première partie des modèles de type Allen-Cahn et Cahn-Hilliard d’ordre élevé avec un potentiel régulier et des modèles de type Allen-Cahn d’ordre élevé avec un potentiel logarithmique. En outre, nous étudions des modèles anisotropes d’ordre élevé et des généralisations d’ordre élevé de l’équation de Cahn-Hilliard avec des applications en biologie, traitement d’images, etc. Nous étudions également la relaxation hyperbolique d’équations de Cahn-Hilliard anisotropes d’ordre élevé. Dans la seconde partie, nous proposons des schémas semi-discrets semi-implicites et implicites et totalement discrétisés afin de résoudre l’équation aux dérivées partielles non linéaire décrivant à la fois les effets élastiques et électrostatiques de condensateurs MSEM. Nous faisons une analyse théorique de ces schémas et de la convergence sous certaines conditions. De plus, plusieurs simulations numériques illustrent et appuient les résultats théoriques. / This thesis is devoted to the theoretical and numerical study of several nonlinear partial differential equations, which occur in the mathematical modeling of phase separation and micro-electromechanical system (MEMS). In the first part, we study higher-order phase separation models for which we obtain well-posedness and dissipativity results, together with the existence of global attractors and, in certain cases, numerical simulations. More precisely, we consider in this first part higher-order Allen-Cahn and Cahn-Hilliard equations with a regular potential and higher-order Allen-Cahn equation with a logarithmic potential. Moreover, we study higher-order anisotropic models and higher-order generalized Cahn-Hilliard equations, which have applications in biology, image processing, etc. We also consider the hyperbolic relaxation of higher-order anisotropic Cahn-Hilliard equations. In the second part, we develop semi-implicit and implicit semi-discrete, as well as fully discrete, schemes for solving the nonlinear partial differential equation, which describes both the elastic and electrostatic effects in an idealized MEMS capacitor. We analyze theoretically the stability of these schemes and the convergence under certain assumptions. Furthermore, several numerical simulations illustrate and support the theoretical results.

Les traitements antireflets (AR) sont très largement utilisés pour améliorer la transmission de systèmes optiques composés de hublots, lentilles, de lames séparatrices,… Dans cette thèse les gammes spectrales visées sont le visible étendu [400-1800nm] et le moyen infrarouge [3,7-4,8µm]. La méthode de nanostructuration par dépôts de films minces utilisant des techniques PVD en incidence oblique (Oblique Angle Deposition) a été choisie car elle permet d’envisager des AR hautes performances sur une large gamme de longueur d’onde, via un procédé industrialisable. L’introduction de porosité via le contrôle des angles de dépôt est utilisée pour nanostructurer l’architecture de chaque couche et de l’empilement ; méthode permettant de modifier et d’optimiser les propriétés optiques des couches constituantes en vue d’un design complet optimal. Une cartographie des indices effectifs accessibles par OAD a été dégagée concernant les trois matériaux déposés (TiO2, SiO2 et Ge). Mais les propriétés optiques de ces couches nanostructurées diffèrent largement de celles des couches denses du fait de la présence d’anisotropie, de gradient d’indice, de diffusion et d’absorption. A partir de caractérisations microstructurales, chimiques et optiques poussées (AFM, MEB, MET, tomographie FIB, tomographie MET, EDX, EELS, spectrophotométrie et ellipsométrie généralisée) un modèle optique analytique plus complexe et couplé à des analyses par éléments finis (FDTD) est présenté. L’ensemble du travail a permis d’élaborer par OAD de simples antireflet bicouches démontrant déjà de hauts niveaux de transmission, supérieurs aux traitements AR existants (interférentiel) ou en développement (Moth-eyes). / Anti-reflective (AR) coatings are widely used to improve the transmission of optical systems composed of window, lenses, separating filters,... In this thesis, the spectral ranges targeted are the extended visible [400-1800nm] and the mid infrared [3.7-4.8µm]. Thin film deposition nanostructuring method using oblique angle deposition (oblique angle deposition) PVD technique was chosen because it allows high performance AR to be considered over a wide wavelength range, by an industrial process. The introduction of porosity with the control of deposition angle is used to nanostructure the architecture of each layer and stack; a method for modifying and optimizing the optical properties of the constituent layers for optimal complete design. A mapping of the effective indices accessible by OAD has been identified for the three materials deposited (TiO2, SiO2 and Ge). However optical properties of these nanostructured layers differ greatly from those of dense layers due to the presence of anisotropy, index gradient, diffusion and absorption. Based on advanced microstructural, chemical and optical characterizations (AFM, SEM, TEM, FIB tomography, TEM tomography, EDX, EELS, spectrophotometry and generalized ellipsometry) a more complex analytical optical model coupled with finite element analyses (FDTD) is presented. All the work has enabled OAD to develop simple two-layer anti-reflective coatings that already demonstrate high levels of transmission, superior to existing (interferential) or work in progress (Moth-eyes) AR treatments.

Uma nova metodologia para a medida absoluta da fração efetiva de nêutrons atrasados &beta;eff, baseada em técnicas de análise de ruído microscópico e no modelo de Duas- Regiões, foi desenvolvida no reator IPEN/MB-01. Diferentemente das demais técnicas, tais como o Método de Bennet Modificado, o Método do Número de Nelson e o Método da fonte de 252Cf, a principal vantagem da metodologia proposta é a obtenção de &beta;eff de um modo puramente experimental, sem a necessidade de quaisquer outros parâmetros, sejam estes calculados ou provenientes de outros experimentos. Com a finalidade de validar este novo método, uma série de experimentos Rossi-&alpha; e Feynman-&alpha; foram realizados no reator IPEN/MB-01. De acordo com a metodologia proposta, &beta;eff foi estimado com uma incerteza de 0.67%, a qual atende aos requisitos de precisão almejados. Além disso, o tempo de geração de nêutrons prontos , dentre outros parâmetros, também foi obtido experimentalmente via esta metodologia. Em geral, os parâmetros medidos estão em acordo com resultados provenientes de experimentos de análise de ruído macroscópico. Nas comparações teoria-experimento, os valores de &beta;eff medidos neste trabalho mostram que a biblioteca JENDL3.3 apresenta a melhor performance (dentro de 1%). Esta concordância justifica a redução no yield de fissão do 235U proposta por Sakurai e Okajima. / A new method for absolute measurement of the effective delayed neutron fraction, &beta;eff , based on microscopic noise experiments and the Two-Region Model was developed at the IPEN/MB-01 Research Reactor facility. In contrast with other techniques like the Modified Bennet Method, Nelson-Number Method and 252Cf-Source Method, the main advantage of this new methodology is to obtain the effective delayed neutron parameters in a purely experimental way, eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-&alpha; and Feynman-&alpha; experiments for validation of this method were performed at the IPEN/MB-01 facility, and adopting the present approach, &beta;eff was measured with a 0.67% uncertainty. In addition, the prompt neutron generation time, , and other parameters were also obtained in an absolute experimental way. In general, the final results agree well with values from frequency analysis experiments. The theory-experiment comparison reveals that JENDL-3.3 shows deviation for &beta;eff lower than 1% which meets the desired accuracy for the theoretical determination of this parameter. This work supports the reduction of the 235U thermal yield as proposed by Okajima and Sakurai.

Depuis sa découverte en 1964, l’étude du Fond Diffus Cosmologique dans le domaine des longueurs d’ondes millimétriques est devenue un enjeu majeur de la recherche expérimentale dans le domaine de la cosmologie. En particulier, ses anisotropies en température, mesurées pour la première fois par le satellite COBE puis plus finement par l’expérience WMAP et le satellite PLANCK. L’existence prédite d’anisotropies de polarisation du Fond Diffus Cosmologique est fait actuellement parti du champ d’expérimentation privilégié de l’étude du CMB. En effet, la preuve d’existence des modes B de polarisation, signature unique des ondes gravitationnelles primordiales, fait actuellement l’objet d’une recherche expérimentale intensive par le biais notamment de l’instrument BICEP2 qui aurait détecté sa signature en 2014 dans des valeurs du rapport tenseur sur scalaire r = 0,2. Le projet QUBIC fait parti de ces expériences destinées à révéler les modes B de polarisation grâce à son instrument basé sur la technique des interféromètres et sur le développement de matrice de bolomètres, demandant un champ d’investigation poussé englobant, entre autre, la physique des solides, la physique des basses températures et la cosmologie. La thèse présentée ici se situe dans ce cadre, avec pour objectif l’élaboration d’une matrice de bolomètres dont la performance et l’optimisation devrait permettre d’acquérir la sensibilité nécessaire à l’observation des modes B de polarisation. Les différentes techniques expérimentales acquises au CSNSM d’Orsay permettent en effet d’envisager l’optimisation des éléments clé de la matrice de bolomètre en s’appuyant notamment sur l’alliage amorphe de NbxSi1-x pour l’élaboration d’un senseur thermique optimisé, et sur un matériau novateur, l’alliage de titane-vanadium, pour la mise au point d’un absorbeur de rayonnement supraconducteur efficace, dont la faible chaleur spécifique doit permettre d’atteindre un temps de réponse du détecteur de l’ordre de la dizaine de milliseconde, valeur du temps de réponse nécessaire à une lecture efficace du signal du Fond Diffus Cosmologique. Le manuscrit de thèse ici présent a pour ambition de développer les principes physiques nécessaires au champ d’investigation du travail à accomplir. Ainsi, cette étude propose d’élaborer les différents éléments d’un bolomètre, réunissant un senseur thermique optimisé ainsi qu’un absorbeur de rayonnement de faible chaleur spécifique, permettant d’envisager la mise au point d’une matrice de bolomètres optimisée dans le cadre du projet QUBIC dont la campagne d’observation est prévue courant 2015 au dôme C du pôle Sud. / Since its discovery in 1964, the study of the Cosmic Microwave Background (CMB) in the field as of millimetre-length wavelengths became a major stake of experimental research in the field of cosmology. In particular, its anisotropies in temperature, measured for the first time by satellite COBE then more finely by the experiment WMAP and the PLANCK satellite. The predicted existence of anisotropies of polarization of the Cosmic Microwave Background is currently been part of the privileged field of experimentation of the study of the CMB. Indeed, the proof of exists modes B of polarization, single signature of the paramount gravitational waves, currently is the object of an intensive experimental research by the means in particular of the instrument BICEP2 which would have detected its signature in 2014 in values of the tensor report on scalar R = 0.2. Project QUBIC makes party of these experiments intended to reveal the modes B of polarization thanks to its instrument based on the technique of the interferometers and the development of bolometers array, asking for a thorough field of investigation including, amongst other things, the solid state physics, the physics of the low temperatures and cosmology. The thesis presented here is within this framework, with for objective making of a bolometers array whose performance and optimization should make it possible to acquire the necessary sensitivity to the observation of the B-mode polarization. The various experimental techniques acquired with the CSNSM of Orsay indeed make it possible to consider the optimization of the key elements of the bolometers array while being pressed in particular on amorphous alloy of NbxSi1-x for making of an optimized thermal sensor, and on an innovative material, titanium-vanadium alloy, for the clarification of an effective superconducting absorber of radiation, whose low specific heat must make it possible to reach a response time of the detector about ten millisecond, value of the response time necessary to an effective reading of the signal of the Cosmic Microwave Background. The manuscript of thesis here present has as an ambition to develop the physical principles necessary to the field of investigation of work to be achieved. Thus, this study proposes to work out the various elements of a bolometer, joining together a thermal sensor optimized as well as an absorber of radiation of low specific heat, making it possible to consider the clarification of a bolometers array optimized within the framework of the project QUBIC whose observation campaign is envisaged during 2015 with the dome C of the south pole.

Dans la première partie de ce travail de thèse, nous nous sommes intéressé à l’étude de l’anisotropie magnétique au sein de complexes mononucléaires de Ni(II) et de Co(II) pentacoordinés de géométrie allant de la pyramide à base carrée jusqu’à la bipyramide trigonale. Pour les complexes mononucléaires, nous avons montré que pour une géométrie donnée, la nature de l’ion métallique a une influence importante sur l’anisotropie magnétique.Nous avons étudié l’effet de la géométrie pour un même ion métallique. Dans le cas d’une géométrie bipyramidale trigonale (symétrie C3v), nous avons montré que le complexe de Co(II) possède un axe facile de l’aimantation et donc un blocage de l’aimantation qui conduisent à l’ouverture d’un cycle d’hystérèse à basse température. Ce type de complexe peut donc être utilisé pour le stockage de l’information. Dans la deuxième partie du travail, nous avons étudié les propriétés magnétiques de complexes binucléaires. Un complexe binucléaire de Co(II) pontés par deux Cl- présente un faible couplage ferromagnétique et un blocage de l’aimantation.Enfin, l’autre aspect de ce travail est de réaliser une molécule binucléaire où deux ions anisotropes, chacun possédant un axe facile de l’aimantation, soient faiblement couplés de manière antiferromagnétique. Pour ce faire, nous avons étudié des composés avec des ligands de type cryptant où la géométrie autour des Co(II) est bipyramide trigonale. Nous avons trouvé qu’avec un ligand pontant de type Cl- ou Br-, l’interaction d’échange est beaucoup plus importante que l’anisotropie locale des ions Co(II) conduisant à un comportement magnétique où les ions perdent leur caractère local. Ce travail ouvre la perspective de synthétiser le même type de complexes mais avec des ponts de plus grande taille pour diminuer l’intensité du couplage antiferromagnétique. / In the first part of this thesis, we studied the magnetic anisotropy of pentacoordinated mononuclear Ni(II) and Co(II) complexes possessing geometries from square pyramid to trigonal bipyramid. We have shown that, for a given geometry, the metal ion nature has an important influence on the magnetic anisotropy.Then, we studied for a given metal ion the effect of geometry on its magnetic anisotropy. In the case of a trigonal bipyramidal geometry (C3v symmetry), we showed that Co(II) has an Ising type anisotropy (easy axis of magnetization) and thus a blocking of magnetization that leads to an opening of a hysteresis cycle at low temperature. This type of complexes can be used for storing data albeit at low temperature.In the second part of the work, we studied the magnetic properties of binuclear complexes. A binuclear Co(II) complex bridged by two Cl- has a weak ferromagnetic coupling and a blocking of its magnetization.Finally, another aspect of this work was to design binuclear complexes, where two anisotropic ions having each one an easy axis of magnetization, are weakly antiferromagnetically coupled. To do this, we have studied compounds with cryptand ligands where the geometry around the Co (II) is trigonal bipyramid. We found that with a Cl- or Br- bridging ligand, the exchange interaction is much more important than the local anisotropy of Co(II) ions leading to a magnetic behavior where the ions lose their local character. This work opens up prospects for synthesizing the same type of complex but with larger bridges to decrease the intensity of the antiferromagnetic coupling.

Le problème d'estimer une fonction de plusieurs variables à partir d'une observation corrompue surgit dans de nombreux domaines d'ingénierie. Par exemple, en imagerie médicale cette tâche a attiré une attention particulière et a, même, motivé l'introduction de nouveaux concepts qui ont trouvé des applications dans de nombreux autres domaines. Cet intérêt est principalement du au fait que l'analyse des données médicales est souvent effectuée dans des conditions difficiles car on doit faire face au bruit, au faible contraste et aux transformations indésirables inhérents aux systèmes d'acquisition. D'autre part , le concept de parcimonie a eu un fort impact sur la reconstruction et la restauration d'images au cours des deux dernières décennies. La parcimonie stipule que certains signaux et images ont des représentations impliquant seulement quelques coefficients non nuls. Cela est avéré être vérifiable dans de nombreux problèmes pratiques. La thèse introduit de nouvelles constructions d'a priori de parcimonie dans le cas des ondelettes et de la variation totale. Ces constructions utilisent une notion d'anisotopie généralisée qui permet de regrouper des variables ayant des comportements similaires : ces comportement peuvent peut être liée à la régularité de la fonction, au sens physique des variables ou bien au modèle d'observation. Nous utilisons ces constructions pour l'estimation non-paramétriques de fonctions. Dans le cas des ondelettes, nous montrons l'optimalité de l'approche sur les espaces fonctionnelles habituels avant de présenter quelques exemples d’applications en débruitage de séquences d'images, de données spectrales et hyper-spectrales, écoulements incompressibles ou encore des images ultrasonores. En suite, nous modélisons un problème déconvolution de données d'imagerie par résonance magnétique fonctionnelle comme un problème de minimisation faisant apparaître un a priori de variation totale structuré en espace-temps. Nous adaptons une généralisation de l'éclatement explicite-implicite pour trouver une solution au problème de minimisation. / The problem of estimating a multivariate function from corrupted observations arises throughout many areas of engineering. For instance, in the particular field of medical signal and image processing, this task has attracted special attention and even triggered new concepts and notions that have found applications in many other fields. This interest is mainly due to the fact that the medical data analysis pipeline is often carried out in challenging conditions, since one has to deal with noise, low contrast and undesirable transformations operated by acquisition systems. On the other hand, the concept of sparsity had a tremendous impact on data reconstruction and restoration in the last two decades. Sparsity stipulates that some signals and images have representations involving only a few non-zero coefficients. The present PhD dissertation introduces new constructions of sparsity priors for wavelets and total variation. These construction harness notions of generalized anisotropy that enables grouping variables into sub-sets having similar behaviour; this behaviour can be related to the regularity of the unknown function, the physical meaning of the variables or the observation model. We use these constructions for non-parametric estimation of multivariate functions. In the case of wavelet thresholding, we show the optimality of the procedure over usual functional spaces before presenting some applications on denoising of image sequence, spectral and hyperspectral data, incompressible flows and ultrasound images. Afterwards, we study the problem of retrieving activity patterns from functional Magnetic Resonance Imaging data without incorporating priors on the timing, durations and atlas-based spatial structure of the activation. We model this challenge as a spatio-temporal deconvolution problem. We propose the corresponding variational formulation and we adapt the generalized forward-backward splitting algorithm to solve it.