Dissertations / Theses on the topic 'SiOx Matrix'

This thesis examines the luminescence properties of nanoscale silicon (Si) by using spectroscopic techniques. Since the development of new optical devices requires understanding light emission mechanism optical spectroscopy has become more important tool in the analysis of these structures. In this thesis, Si nanocrystals embedded in SiO2 matrix will be studied. Photoluminescence (PL) and Time-resolved photoluminescence spectroscopy (TRPL) have been used to detect the light emission in UV-Vis-NIR range. Experiments have been performed in the temperature range 10-300 K. PL is sensitive to impurities and defects that affect materials quality and device performance. In this context, the role of defects in limiting the luminescence of Si nanocrystals and the removal of these defects by hydrogen passivation has been investigated. v TRPL was employed to determine the time evolution of photoluminescence as function of temperature. The decay time of the PL spectra was determined by a stretched exponential function and perfectly fitted to an expression based on three excitonic levels. Carrier lifetimes associated with these three levels were determined and compared with literature. Additionally, temporal variation of PL from free-standing Si nanoparticles is studied under a strong laser illumination. The observed bleaching behavior (time dependent emission intensity), which is reversible, have discussed in terms of exciton trapping at the interface between nanocrystal and the surrounding oxide layer. The results of this thesis will provide new insight on the understanding of light emission mechanism of Si nanocrytals.

A lower-alkalinity cement based on MgO and SiO2 blends is analysed to develop clinker-free Fibre Reinforced Cementitious Composites (FRCC) with cellulosic fibres in order to solve the durability problems of this type of fibres when used in FRCC with Portland cement. Hydration evolution from 7 to 28 days of different MgO-SiO2 formulations is assessed. The main hydration products are Mg(OH)2 and M-S-H gels for all the formulations studied regardless of age. Hardened pastes are obtained with pH values < 11 and good mechanical properties compared to conventional Portland cement. 60% MgO-40% SiO2 system is chosen as optimal for the development FRCC since is the most mechanical resistant and is less alkaline compared with 70% MgO-30% SiO2. FRCC based on magnesium oxide and silica (MgO-SiO2) cement with cellulose fibres are produced to study the durability of lignocellulosic fibres in a lower pH environment than the ordinary Portland cement (PC). Flexural performance and physical tests (apparent porosity, bulk density and water absorption) of samples at 28 days and after 200 accelerated ageing cycles (aac) are compared. Two types of vegetable fibres are utilised: eucalyptus and pine pulps. MgO-SiO2 cement preserves cellulosic fibres integrity after ageing, so composites made out of MgO-SiO2 exhibit significant higher performance after 200 cycles of accelerated ageing than Portland cement composites. High CO2 concentration environment is evaluated as a curing treatment in order to optimise MgO- SiO2 matrices in FRCC. Samples are cured under two different conditions: 1) steam water curing at 55°C and 2) a complementary high CO2 concentration (20% by volume). In carbonated samples, Mg(OH)2 content is clearly lowered while new crystals of hydromagnesite [Mg5 (CO3)4⋅(OH) 2⋅4H2O] are produced. After carbonation, M-S-H gel content is also reduced, suggesting that this phase is also carbonated. Carbonation affects positively to the composite mechanical strength and physical properties with no deleterious effects after ageing since it increases matrix rigidity. The addition of sepiolite in FRCC is studied as a possible additive constituent of the binding matrix. Small cement replacement (1 and 2% wt.) by sepiolite is introduced and studied in hardened cement pastes and, later, in FRCC systems. When used only in cement pastes, it improves Dynamic Modulus of Elasticity over time. Bending tests prove the outcome of this additive on the mechanical performance of the composite: it improves composite homogeneity. Ageing effects are reported after embedding sisal fibres in MgO-SiO2 and PC systems and submitting them to different ageing conditions. This comparative study of fibre degradation applied in different cementitious matrices reveals the real compatibility of lignocellulosic fibres and Mg-based cements. Sisal fibres, even after accelerated ageing, do neither suffer a significant reduction in cellulose content nor in cellulose crystallinity and crystallite size, when exposed to MgO-SiO2 cement. Fibre integrity is preserved and no deposition of cement phases is produced in MgO-SiO2 environment.
Um cimento de baixa alcalinidade à base de blendas de MgO e SiO2 é analisado para o desenvolvimento de Compósitos Cimentícios Reforçados com Fibras (CCRF) celulósicas sem clínquer para resolver os problemas de durabilidade de este tipo de fibras quando são usadas em CCRF com cimento Portland. A evolução da hidratação, desde 7 aos 28 dias, das diferentes formulações é avaliada. Os principais produtos hidratados são o Mg(OH)2 e o gel M-S-H para todas as formulações independentemente da idade estudada. As pastas endurecidas apresentam valores de pH < 11 e bom desempenho mecânico comparado com o cimento Portland convencional. O sistema 60% MgO-40% SiO2 é escolhido como a formulação ótima para o desenvolvimento de CCRF já que é a mais resistente e menos alcalina comparada com 70% MgO-30% SiO2. CCRF com cimento à base de óxido de magnésio e sílica (MgO-SiO2) e fibras celulósicas são produzidos para a análise da durabilidade das fibras lignocelulósicas em ambientes com valores de pH mais baixos comparados com o cimento Portland (PC). O desempenho mecânico a flexão e os ensaios físicos (porosidade aparente, densidade aparente e absorção de água) são comparados aos 28 dias e após de 200 ciclos de envelhecimento acelerado. O cimento à base de MgO-SiO2 preserva a integridade das fibras após o envelhecimento. Os compósitos produzidos com este cimento exibem melhores propriedades após 200 ciclos de envelhecimento acelerado que os compósitos produzidos com cimento Portland. Ambientes com alta concentração de CO2 são avaliados como tratamento de cura para otimizar as matrizes MgO- SiO2 nos CCRF. As amostras são curadas sob 2 condições diferençadas: 1) cura com vapor de água a 55oC e 2) cura com alta concentração de CO2 (20% do volume). As amostras carbonatadas apresentam teores reduzidos de Mg(OH)2 enquanto é produzida uma nova fase cristalina: hidromagnesita [Mg5 (CO3)4⋅(OH) 2⋅4H2O]. Após a carbonatação, o conteúdo de gel M-S-H é reduzido também, indicando uma carbonatação desta fase. A carbonatação aumenta a rigidez da matriz o que influi positivamente no desempenho mecânico e as propriedades físicas dos compósitos sem efeitos prejudiciais ao longo prazo. A adição de sepiolita em CCRF é estudada como possível adição na composição da matriz aglomerante. Baixos teores (1 e 2% em massa) de cimento são substituídos por sepiolita para o estudo das pastas de cimento hidratado e, posteriormente, dos compósitos. O Módulo Elástico Dinâmico das pastas é incrementado com o tempo pela adição de sepiolita. Os ensaios a flexão demostram que a adição de sepiolita melhora a homogeneidade dos compósitos. Reportam-se os efeitos das fibras de sisal após da exposição a sistemas MgO-SiO2 e PC e submetidas a diferentes condições de envelhecimento. Este estudo comparativo da degradação das fibras expostas a diferentes matrizes cimentícias mostra a compatibilidade das fibras lignocelulósicas com os cimentos à base de Mg. As fibras de sisal, inclusive após o envelhecimento acelerado, não apresentam nem redução significativa no conteúdo de celulose nem na cristalinidade da celulose assim como do tamanho de cristalito, quando expostas a cimentos MgO-SiO2.

Mestrado em Ciência e Engenharia de Materiais
O principal objectivo desta dissertação foi estudar novas perspectivas na preparação de nanocompósitos de matriz polimérica, através da síntese e caracterização de nanomateriais do tipo SiO2/ polímero e CdS/ polímero. O primeiro capítulo consiste numa revisão bibliográfica, com destaque para os principais tópicos discutidos ao longo da tese. São efectuadas algumas considerações sobre a utilização de nanopartículas inorgânicas como cargas, e sobre os aspectos mais relevantes da aplicação de polímeros como matrizes. São ainda descritas, algumas estratégias utilizadas para compatibilizar estes componentes. A revisão é concluída com uma breve descrição das metodologias aplicadas na preparação de nanocompósitos de matriz polimérica. No segundo capítulo apresenta-se a síntese e caracterização das cargas inorgânicas. Seguindo métodos descritos na literatura, foram preparadas nanopartículas de SiO2, esféricas e sob a forma de fibras ocas, nanocristais de CdS e compósitos inorgânicos do tipo SiO2@CdS. Estes últimos, foram sujeitos a um tratamento superficial orgânico com TOPO e ainda com SiO2. Para os materiais tratados com TOPO verificou-se uma melhoria das suas propriedades ópticas, nomeadamente ao nível da fotoluminescência à temperatura ambiente. No terceiro e quarto capítulos, são apresentados os nanocompósitos do tipo SiO2/ polímero, que foram sintetizados por polimerização in situ de matrizes semicristalinas (poliamidas e poliuretanos), e amorfas (poli(estireno)). A sua caracterização foi efectuada por espectroscopia de IV, SEM, TEM, TGA e DSC. Os nanocompósitos de matriz semicristalina foram preparados por polimerização por etapas. No caso das poliamidas, foi investigada a influência das cargas de SiO2 com diferentes morfologias e tratamentos de superfície, no processos de fusão e cristalização da matriz. Os materiais de matriz amorfa foram preparados por polimerização radicalar em emulsão e dispersão. Neste caso o estudo incidiu sobre a morfologia das partículas dos nanocompósitos, nas possíveis condições experimentais que a determinam e na influência destas sobre as propriedades térmicas do nanocompósito. Por fim descreve-se no quinto capítulo a síntese e caracterização dos nanocompósitos do tipo CdS/ polímero. Estes materiais foram preparados por polimerização radicalar em solução, na presença de nanocristais de CdS, e compósitos inorgânicos do tipo SiO2@CdS. A inserção das cargas na matriz promoveu as suas propriedades de fotoluminescência à temperatura ambiente. Foram ainda avaliadas as propriedades térmicas de algumas amostras representativas. Neste trabalho foram preparados uma série de novos nanocompósitos de matriz polimérica, que fazem antever futuras aplicações tecnológicas. Foram ainda estabelecidos novos caminhos para a compreensão dos mecanismos de formação de materiais híbridos, e das interacções que ocorrem ao nível das interfaces de natureza orgânica/ inorgânica.
The aim of this thesis was to study new methods for the preparation of polymer based nanocomposites, through the synthesis and characterisation of SiO2/polymer and CdS/ polymer nanomaterials. The first chapter consists in an introduction to the aim topics that are discussed in the thesis as well as a literature review. Some considerations are made regarding the use of inorganic nanoparticles as fillers, and to the methods used to modify the inorganic materials surface in order to make them more compatible with the organic nature of polymeric matrices. In this introduction some relevant aspects of the use of polymers as matrices are reported, and a brief review of the polymerisation methods to be used in the nanocomposites preparation is given. The second chapter is devoted to the preparation and characterisation of the fillers. Following methods previously described on the literature, SiO2 nanoparticles with spherical and hollow fibres morphologies, CdS nanocristalites and SiO2@CdS inorganic composites were prepared. The last were organically treated with TOPO and also with SiO2. It was concluded that the TOPO capping results in improved room temperature photoluminescence properties. In the third and fourth chapters, the synthesis and characterisation of SiO2/ polymer nanocomposites is discussed. Using several in situ polymerisation techniques semi-crystalline (polyurethanes and polyamides) and amorphous (poly(styrene)) matrices were prepared. The materials were characterised by FTIR spectroscopy, TEM and SEM, TGA and DSC analysis. The semicrystalline polymeric matrix nanocomposites were prepared by steppolymerisation. In the case of the polyamide based nanocomposites the influence of the SIO2 nanoparticles on the melting and crystallization behaviour of the matrices is discussed. As regards the amorphous matrix nanocomposites these were prepared by radical emulsion and dispersion polymerisation. The morphology of the nanocomposite particles is discussed in light of changes in experimental conditions, and its possible influence on thermal properties. Finally, the chapter five is concerned with CdS/ polymer nanocomposites prepared by in situ polymerisation in the presence of CdS nanocrystals, and SiO2@CdS inorganic composites. TOPO capping results in higher affinity of the fillers to the matrix, and its insertion on the matrices promotes their optical properties, namely room temperature photoluminescence. The thermal properties of some representative samples were also studied. In this work a wide range of novel polymer based nanocomposites were prepared. This study showed that nanomaterials have unique properties that can anticipate potential technologic applications. Furthermore, new routes have been opened to the understanding of the mechanisms of nanocomposites formation, as well as the nature of interactions between organic/ inorganic interfaces.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this work, we study the magnetic properties of CoFe2O4 nanoparticles dispersed in silica (SiO2) matrix. Samples were produced by the sol-gel method and synthesized at different temperatures. The average distance between the particles and thus the nature of inter-particle interactions were controlled for using different concentrations of iron and cobalt salts and the starting material tetraethylorthosilicate (TEOS). The samples were characterized by thermogravimetry (TG), X-ray fluorescence (XRF), X-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetization as a function of magnetic field and temperature. Thermogravimetric analysis showed that the weight loss increases with increasing concentration of salts in the starting solution. The results of X-ray diffraction combined with the transmission electron microscope images confirmed the presence of CoFe2O4 nanoparticles dispersed into the SiO2 matrix. Magnetization measurements showed a typical behavior generally showed by a magnetic nanoparticles system, that is, the observation of a peak in the curve FC-ZFC with a thermal hysteresis in the low temperature region. In particular, we observed a dependence of the coercive field with temperature of CoFe2O4 nanoparticles that did not follow the predictions of the model Bean-Livingston. We believe that this fact is linked more to the effect of size distribution than the possible effects of interaction between the nanoparticles. In this regard, a model considering a particle size distribution in the coercivity of nanoparticles was used. The model was able to fit the experimental data to wide temperature range.
Neste trabalho, nós estudamos as propriedades magnéticas de nanopartículas de CoFe2O4 dispersas em uma matriz de sílica (SiO2). As amostras foram produzidas através do método sol-gel para diferentes temperaturas de síntese. A distância média entre as partículas e, deste modo, a natureza das interações inter-partículas foram controladas utilizando diferentes concentrações dos sais de ferro e cobalto e do reagente de partida tetraetilortossilicato (TEOS). As amostras foram caracterizadas através de medidas de termogravimetria (TG), fluorescência de raios X (FRX), difração de raios X (DRX), microscopia eletrônica de transmissão (MET) e magnetização em função do campo magnético e da temperatura. As análises termogravimétricas mostraram que a perda de massa aumenta com o aumento da concentração dos sais de partida na solução. Os resultados de difração de raios X combinados com as imagens de microscopia eletrônica de transmissão confirmaram a presença das nanopartículas de CoFe2O4 dispersas dentro da matriz de SiO2. As medidas de magnetização mostraram um comportamento típico de um sistema de nanopartículas magnéticas, ou seja, o aparecimento de um pico na curva de ZFC-FC com uma histerese térmica na região de baixas temperaturas. Em particular, nós observamos uma dependência do campo coercivo com a temperatura das nanopartículas de CoFe2O4 que não seguiu as previsões do modelo de Bean Livingston. Nós acreditamos que esse fato está ligado muito mais ao efeito da distribuição de tamanhos do que aos possíveis efeitos de interação entre as nanopartículas. Neste sentido, um modelo que considera a distribuição de tamanhos de partículas na coercividade das nanopartículas foi utilizado. O modelo foi capaz de ajustar os dados experimentais para amplo intervalo de temperatura.

Orientador: Yoshitaka Gushikem
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-20T16:56:50Z (GMT). No. of bitstreams: 1 Canevari_ThiagodaCruz_D.pdf: 2821542 bytes, checksum: 1a2c7ff35fcd8e34d5867b81b4bb960b (MD5) Previous issue date: 2012
Resumo: Este trabalho tem como objetivo sintetizar e caracterizar três materiais diferentes obtidos pelo processo sol-gel: SiO2/SnO2, SiO2/SnO2/Sb2O5 e o filme de Nb2O5 formado sobre a superfície do material cerâmico SiO2/C e utilizá-los como matriz no desenvolvimento de sensores eletroquímicos. O óxido misto, SiO2/SnO2, foi sintetizado utilizando como fonte de SnO2, SnCl4.5H2O, utilizando diferentes catalisadores ácidos HCl e HF (F-). As diferenças estruturais e morfológicas apresentadas pelos óxidos mistos, SiO2/SnO2, em virtude do uso de diferentes catalisadores ácidos, foram investigadas por meio das isotermas de adsorção/dessorção de N2, espectroscopia de fluorescência de raios X, difração de raios X, espectroscopia na região do infravermelho, microscopia eletrônica de transmissão, espectroscopia fotoeletrônica de raios X (XPS), medidas de condutividade elétrica e medidas eletroquímicas visando a utilização destes óxidos mistos como matriz suporte para desenvolvimento de sensores eletroquímicos. O material, SiO2/SnO2/Sb2O5, foi obtido por meio da incorporação do Sb2O5 sobre a superfície do óxido misto, SiO2/SnO2, previamente sintetizado utilizando como fonte de SnO2, o dibutildiacetato de estanho. Este recobrimento foi realizado utilizando, CH2Cl2 seco, em atmosfera inerte, pela técnica de "Enxerto¿. O material, SiO2/SnO2/Sb2O5, foi caracterizado por meio da isoterma de adsorção/dessorção de N2, espectroscopia de fluorescência de raios X, microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e espectroscopia fotoeletrônica de raios X (XPS). Sobre este material foi imobilizado o corante catiônico, azul de meldola, no qual foi preparado um eletrodo de disco rígido com objetivo de estudar a eletrooxidação do cofator NADH utilizando as técnicas de voltametria cíclica e cronoamperometria visando o desenvolvimento de um biossensor eletroquímico. A formação do filme de Nb2O5 sobre a superfície do material carbono cerâmico SiO2/C, utilizando a técnica de spin-coating, foi realizado após o material SiO2/C ser sintetizado utilizando o processo sol-gel. O filme de Nb2O5 preparado foi caracterizado utilizando a técnica de microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e espectroscopia fotoeletrônica de raios X (XPS). Com este material foi preparado um eletrodo de disco rígido com objetivo de estudar a eletrooxidação dos isômeros fenólicos, hidroquinona e catecol na presença de resorcinol utilizando a técnica de voltametria de pulso diferencial
Abstract: This work describes the synthesis and characterization of three different materials: SiO2/SnO2, SiO2/SnO2/Sb2O5 and the film of Nb2O5 formed on the surface of the ceramic material SiO2/C obtained by sol-gel process and to use them as matrix in the development of electrochemical sensors. The mixed oxides, SiO2/SnO2, were synthesized using as source of SnO2, SnCl4.5H2O, using different acid catalysts HCl and HF (F). The structural and morphological differences provided by mixed oxides, SiO2/SnO2, due to the use of different catalysts were evaluated by using several like area superficial BET technique, ray X fluorescence spectroscopic, ray X diffraction, IV spectroscopic, transmission electron microscopic (TEM), ray X spectroscopic photoelectron excited (XPS) and electrical conductivity and electrochemical measurements in order to use these mixed oxides as matrix support for development of electrochemical sensors. The material SiO2/SnO2/Sb2O5 was obtained by incorporation of Sb2O5 on the surface of the mixed oxide SiO2/SnO2, previously synthesized using as source of SnO2, dibutildiacetate of tin. This coating was performed using, CH2Cl2 dry, in inert atmosphere, using the technique of "Grafting." The SiO2/SnO2/Sb2O5 material was characterized using area superficial BET technique, ray X fluorescence spectroscopic, scanning electron microscopic (SEM), energy dispersive spectroscopic (EDS) and ray X spectroscopic photoelectron excited (XPS). On this material was immobilized on the cationic dye Meldola Blue, which was prepared in a rigid disk electrode to study the electrooxidation of the cofactor NADH using cyclic voltammetry and chronoamperometry technique for the development of an electrochemical biosensor. The formation of Nb2O5 film on the surface carbon ceramic material SiO2/C, using the technique of spin-coating was carried out after material for SiO2/C is synthesized using the sol-gel process. Nb2O5 film prepared was characterized using scanning electron microscopic (SEM), energy dispersive spectroscopic (EDS) and ray X spectroscopic photoelectron excited (XPS). With this material was prepared a disc rigid electrode in order to study the electrooxidation of phenolic isomers, hydroquinone and catechol in the presence of resorcinol using differential pulse voltammetry technique
Doutorado
Quimica Inorganica
Doutor em Ciências

A new approach to obtain visible luminescence from sol-gel derived SiOC films is proposed. This novel method is based on a simple processing route to produce nanostructured multicomponent ceramics. According to this route, hybrid sol-gel derived precursors are converted to ceramic materials by a pyrolysis process in controlled atmosphere at 800-1000°C. Higher temperatures lead to formation of Si-rich SiOC, C-rich SiOC or stoichiometric SiOC according to the starting composition. The final composition, which is relevant to line emission, can be easily controlled through a number of processing parameters like the composition of the preceramic gel and the heat treatment conditions. Thus, this new processing method seems very well suited for the production of white emitting materials since the Si- and C-based emission can be tuned across the visible spectral range from UV-blue to red by controlling film composition. A further advantage of this method is that the thin films can be formed on Si or quartz wafers and this can serve as starting material to process more complex photonic devices such as waveguides or LEDs. In the amorphous state (800-100°C), all SiOC films showed UV-blue luminescence peaking at about 410 nm, which is attributed to defect states present in the matrix such as dangling bonds. The increase of the pyrolysis temperature (≥1100°C) led to the partition of SiOC and formation of SiC, C and Si phases. The intense green-yellow luminescence observed in stoichiometric SiOC films caused by the presence of SiC and very low amount of free C. On the other hand, Si rich SiOC film showed a very broad and extremely intense white luminescence peak centred at 620 nm covering almost all visible range (430 nm-900 nm) at 1200 °C. This behaviour is explained by the simultaneous presence of SiC, C and Si in the film. External quantum efficiency measurements yielded 11.5% and 5% efficiencies in Si rich SiOC and stoichiometric SiOC films, respectively, pyrolysed at 1200°C. On the other hand, C rich SiOC films did not show any noticeable improvement in PL, indicating that C excess in the SiOC system is detrimental for the luminescence behaviour. Solutions which used in thin film production have been characterized extensively by means of several characterization properties. Moreover, the related powders and bulks have been characterized for the sake of coherency and widen the study. In addition, a study on volumetric shrinkage of films and powders has been done. The results showed that the shrinkage in films happens almost 200°C earlier than powder and higher amount of siloxane release due to the low dimension, the shrinkage is higher than powders. The last part of the study dedicated to two different systems, SiBOCs and SiOCNs, in order to understand the effect of the boron addition on SiOC system and study the optical properties of the SiOCN. Tunable (color emission change) SiOC films is obtained with high quantum efficiency by adding very few amount of boron in SiOC. Moreover, the processing temperature is decreased and very broad emission is obtained. Finally, results showed that SiOCN PDC gives very high emission in UV range and they are promising materials for UV-LEDs.

A new approach to obtain visible luminescence from sol-gel derived SiOC films is proposed. This novel method is based on a simple processing route to produce nanostructured multicomponent ceramics. According to this route, hybrid sol-gel derived precursors are converted to ceramic materials by a pyrolysis process in controlled atmosphere at 800-1000°C. Higher temperatures lead to formation of Si-rich SiOC, C-rich SiOC or stoichiometric SiOC according to the starting composition. The final composition, which is relevant to line emission, can be easily controlled through a number of processing parameters like the composition of the preceramic gel and the heat treatment conditions. Thus, this new processing method seems very well suited for the production of white emitting materials since the Si- and C-based emission can be tuned across the visible spectral range from UV-blue to red by controlling film composition. A further advantage of this method is that the thin films can be formed on Si or quartz wafers and this can serve as starting material to process more complex photonic devices such as waveguides or LEDs. In the amorphous state (800-100°C), all SiOC films showed UV-blue luminescence peaking at about 410 nm, which is attributed to defect states present in the matrix such as dangling bonds. The increase of the pyrolysis temperature (≥1100°C) led to the partition of SiOC and formation of SiC, C and Si phases. The intense green-yellow luminescence observed in stoichiometric SiOC films caused by the presence of SiC and very low amount of free C. On the other hand, Si rich SiOC film showed a very broad and extremely intense white luminescence peak centred at 620 nm covering almost all visible range (430 nm-900 nm) at 1200 °C. This behaviour is explained by the simultaneous presence of SiC, C and Si in the film. External quantum efficiency measurements yielded 11.5% and 5% efficiencies in Si rich SiOC and stoichiometric SiOC films, respectively, pyrolysed at 1200°C. On the other hand, C rich SiOC films did not show any noticeable improvement in PL, indicating that C excess in the SiOC system is detrimental for the luminescence behaviour. Solutions which used in thin film production have been characterized extensively by means of several characterization properties. Moreover, the related powders and bulks have been characterized for the sake of coherency and widen the study. In addition, a study on volumetric shrinkage of films and powders has been done. The results showed that the shrinkage in films happens almost 200°C earlier than powder and higher amount of siloxane release due to the low dimension, the shrinkage is higher than powders. The last part of the study dedicated to two different systems, SiBOCs and SiOCNs, in order to understand the effect of the boron addition on SiOC system and study the optical properties of the SiOCN. Tunable (color emission change) SiOC films is obtained with high quantum efficiency by adding very few amount of boron in SiOC. Moreover, the processing temperature is decreased and very broad emission is obtained. Finally, results showed that SiOCN PDC gives very high emission in UV range and they are promising materials for UV-LEDs.

Globalization has increased the complexity of the business world, as it adds new dimensions to companies’ operations, such as global suppliers and customers, and competition from global actors. To handle the complexity, companies are pressured to become more data-driven to be able to measure and align their operations, and create possibilities for efficiency and competitiveness [Skjott-Larsen etal., 2007; Long, 2018]. In order to enable the change towards becoming more data-driven, companies need to rethink the structure of their organization. Matrix structures have gained popularity, since it allows companies to focus on more than one dimension by creating functional teams focused on specific tasks [Sy et al., 2005]. However, it is not uncommon that the functional groups becomes functional silos, with an inward focus on the own groups’ performance, leading to decreased understanding of other groups and poor communication between groups. A lack of understanding of other groups can lead to a reactive, rather than proactive, way of handling problems [Motiwalla and Pearson, 2009]. The purpose of this project is to create a process that can be used to facilitate proactive work in adata-driven matrix organization struggling with a reactive way of handling problems. The process can be used as a way to decide between possible solutions in decision-making processes, while making sure that any affected department is involved at an early stage in the decision-making process. At Alfa Laval’s distribution center (DC) in Tumba, they are facing the challenges of functional silos and reactive work. The organization is data-driven, why a lot of decisions are based on data. However, the best decision according to the data is not always feasible, which has lead to decisions being made that affects other departments negatively. Based on data from and observations made at the DC, a processwas created. The process was iterated and improved through application to real-life problems and point of improvements identified at DC Tumba. While it is based on the operations at Alfa Laval, it canbe applied to any organization facing similar challenges. The final version of the process proved to deliver good solutions to problems by involving stakeholders early on in the process, making it possible for them to influence how the solutions should be adjusted in order to avoid the changes affecting their daily work negatively. The most important conclusion is that important stakeholder departments should be involved earlyin decision-making processes. That way, their valuable competence and knowledge can be utilized when identifying possible solution, and any negative effects of a solution on another departments can be discovered before implementation. In addition, by taking the time to thoroughly analyze the root cause and effects to a problem, the understanding of the chain can increase.
Globalisering har ökat komplexiteten av affärsvärlden, då ytterligare dimensioner måste tas hänsyn till i företags verksamheter, så som globala leverantörer och kunder, och ökad konkurrens från globala aktörer. För att hantera komplexiteten blir företag mer datadrivna, för att kunna mäta och samordna sin verksamhet och skapa möjligheter för effektivitet och konkurrenskraftighet [Skjott-Larsen et al.,2007; Long, 2018]. För att möljiggöra ett skifte mot att bli mer datadriven, måste företag se över sin organisationsstruktur. Matrisstrukturer har ökat i popularitet då de möjliggör att företag kan fokusera på fler än en dimensioner samtidigt genom att skapa funktionella grupper fokuserade på specifikauppgifter [Sy et al., 2005]. Dock är det inte ovanligt att funktionella grupper förvandlas till funktionella silos, med ett inåtriktat fokus på den egna gruppens prestationer, vilket leder till minskad förtåelse och bristfällig kommunikation grupper emellan. Bristande förståelse för andra grupper kan leda till ett klimat där problem hanteras reaktivt snarare än proaktivt [Motiwalla and Pearson, 2009]. Syftet med detta projekt är att skapa en process som kan användas för att underlätta proaktivt arbetet i en datadriven organisation där problem hanteras reaktivt. Processen kan användas som ett hjälpmedel för att välja den bästa av flera möjliga lösningar, samtidigt som påverkade avdelningar involveras i ett tidigt stadium av beslutsprocessen. På Alfa Lavals distributionscenter (DC) i Tumba, finns utmaningar med funktionella silos och reaktivt arbete. Organisationen är datadriven, och beslut fattas baserat på data. Dock är inte alltid beslut som baserats på data rimliga, vilket har lett till att beslut tas som påverkar andra avdelningar negativt. Baserat på data från och observationer på DCt, skapades en preliminär process. Processen itererades och förbättrades sedan genom att appliceras på verkliga problem och förbättringsområden som identifierades på DC Tumba. Även om processen togs fram och baserades på Alfa Lavals verksamhet, kan den appliceras på andra organisationer som står inför samma utmaningar. Den slutgiltiga versionen av processen visade sig generera bra lösningar till problemen genom att involvera intressenter tidigt i processen, vilket gav dem möjligheten att påverka hur den rekommenderade lösningen skulle justeras för att undvika att dereas dagliga arbete skulle påverkas negativt. Den viktigaste slutsatsen är att det är viktigt att involvera intressentavdelningar i ett tidigt skede i beslutsfattandeprocesser. På så sätt kan deras värdefulla kompetens och kunskaper nyttjas när potentiella lösningar till ett problem genereras, och negativa effekter från lösningen på andra avdelningar kan upptäckas innan implementering. Att dessutom noggrant analysera roten till problemet och dess effekter kan leda till att förståelsen för hela kedjan ökar.

Negli ultimi decenni, nell’ambiente aziendale sta prendendo sempre più piede l’utilizzo di modelli specifici per l’approccio all’innovazione. Dei più comuni e utilizzati in letteratura, quelli analizzati in questo studio, sono lo Stage and Gate per lo sviluppo di nuovi prodotti, il Lean six-sigma per progetti di miglioramento, l’Agile per ottimizzare e velocizzare i processi, la Lean per ridurre gli sprechi e il Design Thinking per comprendere meglio i bisogni del cliente. Per sfruttare al meglio ogni modello è bene che le aziende abbiano una linea guida che illustri quando utilizzare e in che modo ogni metodologia. In questa identificazione, oltre all’utilizzo lineare e puro degli approcci all’innovazione, possono emergere delle situazioni in cui risulti necessario utilizzare contemporaneamente più modelli così da usufruire di una metodologia ibrida che colga i benefici rispettivi di ogni modello integrato. Con questa ambizione, lo scopo di questa tesi è stato quello di realizzare una matrice dei modelli ibridi che identificasse per ogni area, rappresentante le possibili situazioni, il modello, puro o ibrido, più idoneo da applicare. Esaminando le pratiche dell’azienda di riferimento, si sono individuate le variabili tipiche che identificano e caratterizzano i contesti in cui si realizzano i progetti di innovazione. In base a queste variabili si è costruita la struttura della matrice in cui clusterizzare i vari progetti. Analizzando poi i modelli già in uso in azienda e confrontandosi con la letteratura, si sono individuati i modelli puri e ibridi rispettivi per ogni quadrante. Al termine di queste fasi, è stato possibile studiare ed elaborare la realizzazione di una matrice dei modelli ibridi in grado di fornire l’approccio più corretto da utilizzare in ogni contesto e aiutare l’azienda a raggiungere più velocemente i risultati evitando l’insorgenza di problematiche.

Resumo: Sistemas nanoestruturados de Si tem sido alvo de intensos estudos e discussões no meio científico devido às suas propriedades eletrônicas e ópticas, as quais produzem luminescência no visível, iferentes das apresentadas pelo Si bulk. O presente trabalho traz considerações a respeito de tal luminescência e visa contribuir com as discussões a respeito de sua origem apresentando um estudo detalhado da emissão luminosa de nanocristais Si obtidos pela técnica de implantação iônica de íons de silício (Si+) em matriz de dióxido de silício (SiO2). Utilizando diferentes técnicas ópticas (fotoluminescência em função da temperatura, fotoluminescência resolvida no tempo e excitação de fotoluminescência), um modelo de confinamento esférico e um modelo semi-empírico proposto por Varshni em 1967 para a variação de gap do Si bulk, comparamos os aspectos observados experimentalmente para as emissões envolvidas na luminescência com o comportamento esperado para recombinações banda-a-banda (estados sob confinamento) do nosso sistema. Para nanocristais de diâmetro iguais de 3 nm (diâmetro obtido por microscopia de transmissão de elétrons para nossa amostra) os modelos teóricos descrevem com razoável precisão a energia de luminescência em função da temperatura observada para a emissão mais intensa em maiores energias do espectro de fotoluminescência a baixas temperaturas e as energias dos estados excitados identificados pela técnica de excitação de luminescência. No entanto para altas temperaturas, a dependência da luminescência com a temperatura parece indicar a presença simultânea de estados de superfície emitindo nessa mesma região do espectro. As demais emissões presentes no espectro de fotoluminescência (emissões com energias menores) parecem seguir o padrão de confinamento quanto à evolução do gap com o tamanho de nanopartícula, porém seus comportamentos com a temperatura não nos levam a uma comprovação de emissão via estados confinados, tampouco via estados de superfície, até o momento. Com isso as emissões nessa região do espectro ainda precisam de uma análise mais profunda e cuidadosa para a comprovação dos mecanismos envolvidos em suas bandas. Os resultados aqui apresentados nos permitem sugerir um modelo de emissão luminosa que é dominado pelos efeitos de confinamento quântico a baixas temperaturas, mas que aponta para um eventual domínio de recombinações através de estados ocalizados para temperaturas altas, próximas e superiores à ambiente. Nossa hipótese é que, para estas nanopartículas obtidas através de implantação iônica, os mecanismos de recombinação por estados onfinados e por estados de superfície coexistem, sendo que a importância de cada um depende crucialmente da temperatura.

In this work we will face the problem of the vibrational properties of glasses focusing on the origin and nature of the boson peak (BP). This feature is an universal characteristic of glasses and a fingerprint of the presence of disorder. Two samples have been chosen for this study. The first is permanently densified vitreous SiO$_2$. Permanent densification has been exploited to tune the glassy properties focusing on their evolution. The second sample is a silicon-selenium glass whose low sound velocity allows a detailed study of its dynamics by means of neutron inelastic scattering.

Mestrado em Ciência e Engenharia dos Materiais
O desenvolvimento de novos materiais com propriedades funcionais é uma constante necessidade para a maturação e sustentabilidade da sociedade como um todo. No que diz respeito aos nanocompósitos de matriz polimérica, uma das maiores restrições ao seu uso é a preservação e o controlo das propriedades físicas únicas das cargas de dimensões nanométricas, sendo portanto essencial manter a sua integridade e conseguir dispersões uniformes. Tal é particularmente difícil no caso de nanopartículas anisotrópicas, tais como as fibras de Gd2O3:Eu 3+ revestidas com sílica utilizadas nesta tese. Nesse sentido, estudou-se a utilização de agentes RAFT macromoleculares para preparar nanocompósitos de matriz polimérica inorgânicos quer em solução quer em emulsão. Numa primeira fase estudou-se a preparação do agente RAFT macromolecular a partir do agente RAFT ácido 2-{[(dodeciltio)carbonotioil]tio]-2- metilpropanóico (TTCA) e do ácido acrílico para diferentes graus de conversão, tendo-se obtido polímeros controlados e com distribuições de massa moleculares (PDI) estreitas. Seguidamente, verificou-se que o sistema apresenta as características de um sistema vivo por co-polimerização com o acrilato de butilo (BuA) tanto em emulsão como em solução. No entanto, não se obteve controlo no PDI, nomeadamente quando a polimerização foi realizada em emulsão. Apesar de não se ter conseguido optimizar este sistema, a sua utilização foi explorada na preparação de nanocompósitos de sílica e depois estendido a fibras de Gd2O3:Eu3+ revestidas com sílica. Com o objectivo de aumentar a afinidade entre o polímero e as cargas, as nanopartículas inorgânicas foram funcionalizadas com agentes de acoplamento à base de silano. Os nanocompósitos obtidos foram depois caracterizados por FT-IR, DSC, SEM, e PL. Os resultados obtidos por SEM e FTIR-ATR permitiram confirmar que a preparação dos nancompósitos foi bem sucedida. Porém os resultados de DSC foram inconclusivos e os de fotolumiscência indicam que após funcionalização com o 3-aminopropilo trimetoxisilano (APS) o sinal é reduzido sendo esse efeito agravado após encapsulamento na matriz polimérica. Por fim são apresentados alguns resultados relativos à preparação de filmes finos dos nanocompósitos de modo a avaliar a presença de alguma anisotropia.
New materials with functional properties are a consistent necessity for the maturation and sustainability of society on a whole. One main restriction when polymer based nanocomposites are concerned is the preservation and control of the unique physical properties of the nanometric fillers. However, it is quite essential to maintain their nanoscale integrity and hitherto achieve uniform dispersions, which is extremely challenging especially when anisotropic nanoparticles are brought into the limelight, such as Gd2O3:Eu3+ fibers coated with silica studied in this thesis. In this regard, polymer nanocomposites were devised using a macroRAFT agent both in solution and emulsion. Initially, the homopolymerization of acrylic acid (AA) using 2- {[(dodecylthio)carbonothioyl]thio}-2-methylpropanoic acid (TTC-A), to yield the macroRAFT agent (PAATTC) was studied for varying degrees of conversion and narrow molar mass distributions prevailed. Next, the copolymerization of PAATTC with n-butyl acrylate (nBuA) was carried out in both emulsion and solution conditions to test the livingness of the system which was confirmed, but proved to be uncontrolled. Despite the fact that this system was not optimized, it was utilized in the preparation of silica nanocomposites and extended to the preparation of Gd2O3:Eu3+@silica nanocomposites. In order to increase the affinity between the polymer and the inorganic nanofillers, the latter was functionalized using suitable silane coupling agents. The nanocomposites obtained were characterized by FTIR, SEM, DSC, and PL. While SEM and FTIR, confirmed the successful formation of nanocomposites, the DSC results were inconclusive and the PL results of Gd2O3:Eu3+@silica showed a decrease in the signal intensity, upon functionalization with 3-aminopropyl trimethoxysilane (APS), which was further aggravated upon encapsulation in the polymeric matrix. Finally, some preliminary results regarding the preparation of composite thin films to assess the presence of any anisotropy are documented.

In this work we will face the problem of the vibrational properties of glasses focusing on the origin and nature of the boson peak (BP). This feature is an universal characteristic of glasses and a fingerprint of the presence of disorder. Two samples have been chosen for this study. The first is permanently densified vitreous SiO$_2$. Permanent densification has been exploited to tune the glassy properties focusing on their evolution. The second sample is a silicon-selenium glass whose low sound velocity allows a detailed study of its dynamics by means of neutron inelastic scattering.

Neste trabalho estudam-se as propriedades de nanoestruturas de Ge e Sn formadas em amostras de SiO2/Si(100) através dos processos de implantação iônica e tratamento térmico. A formação de nanocristais de Ge foi investigada em função de tratamentos térmicos em ambiente de N2. Os resultados obtidos foram correlacionados com as propriedades de luminescência das amostras, sendo feita uma discussão sobre os mecanismos atômicos envolvidos no processo de crescimento dos nanocristais de Ge, bem como seus efeitos na criação de centros luminescentes no interior da camada de SiO2, que são responsáveis por intensas bandas de fotoluminescência (PL) nas regiões espectrais do azul-violeta (≈ 3,2 eV) e ultravioleta (≈ 4,2 eV). Além disso, experimentos de irradiação com diferentes íons (He+, Si+, Kr++, Au+) foram realizados antes da implantação do Ge com o objetivo de estudar o efeito de memória que os danos criados pela irradiação apresentam sobre as propriedades estruturais e luminescentes das amostras de SiO2/Si(100) No estudo das amostras de SiO2/Si(100) implantadas com Sn, a síntese de nanopartículas de Sn foi estudada em função da temperatura e do ambiente de tratamento térmico (N2 e vácuo). De maneira pioneira mostrou-se que através da manipulação desses parâmetros é possível formar desde grandes nanocristais bi-fásicos de Sn (≈ 12 a 25 nm) em estruturas concêntricas com núcleo de β-Sn e camada externa de SnOx, até pequenas nanopartículas de Sn com diâmetros de ≈ 2 nm e uniformemente distribuídas ao longo da camada de SiO2. Além disso, observou-se que a evolução estrutural do sistema de nanopartículas de Sn influencia diretamente as características das emissões de PL azul-violeta e UV. Por fim, um outro aspecto das nanoestruturas de Sn foi estudado: a formação de um denso arranjo de ilhas epitaxiais de β-Sn na região de interface SiO2/Si. Este sistema de nano-ilhas, que cresce epitaxialmente, é uniformemente distribuído sobre a superfície do Si, apresentando uma pequena dispersão em tamanho e tendência a se auto-organizar. A criação desse sistema de nano-ilhas epitaxiais através da utilização da implantação iônica é um processo inédito, sendo discutida aqui com base nas propriedades de equilíbrio do sistema Sn-Si.

Ce travail traite de l'elaboration par frittage, de la caracterisation microstructurale (met, meb) et de l'etat des contraintes residuelles d'origine thermique dans les composites a matrice metallique (nickel) et a renforts: dispersion des particules d'oxydes (al#2o#3, sio#2, nio). Le choix du nickel comme phase matricielle est motive par plusieurs considerations. La plus importante est que le nickel possede une symetrie cristalline cubique dont le reseau possede une haute symetrie ; ce qui nous permet d'etudier la perturbation apportee, en terme d'anisotropie de dilatation thermique, par l'ajout d'une dispersion de particules d'oxydes dont les caracteristiques physiques et mecaniques sont differentes de la matrice. La caracterisation microstructurale nous a permis de mettre en evidence d'une maniere directe la reaction a l'interface ni/sio#2 et d'une maniere indirecte la reaction a l'interface ni/al#2o#3 dans les conditions de frittage pendant l'application du cycle thermique. La technique choisie pour etudier les contraintes est celle mettant en uvre la diffraction des rayons x permettant des mesures tres localisees. C'est un outil privilegie pour l'exploration des couches superficielles de quelques microns sur des materiaux cristallises, en plus, la methode est non destructive. Nous avons utilise deux methodes: la premiere consiste a mettre l'echantillon sous un regime de contraintes connu, et etudier les contraintes residuelles du composite en terme de contrainte equivalente ; la seconde permet d'etudier l'evolution de la deformation elastique en fonction de la temperature par chauffage des materiaux composites a des temperatures moderees. La loi des sin#2 a ete appliquee pour determiner les deformations a la surface des materiaux. Ces methodes nous ont permis de determiner les deformations elastiques puis les contraintes qui existent dans la matrice de ces materiaux composites. Ces deformations diminuent au cours du chauffage. L'evolution des deformations en fonction de la temperature est en accord avec un modele mecanique base sur des resultats bibliographiques concernant l'effet d'une particule unique dans une matrice infinie. Les deformations elastiques mesurees sont de loin plus faibles que ce qui est attendu theoriquement. Ce resultat nous fait penser a la relaxation des contraintes par deformation plastique dans la matrice et a l'interface particules d'oxydes / matrice nickel ; la deformation plastique est d'autant plus importante que la difference des coefficients d'expansion thermique entre nickel et oxyde est importante

Significant advances in modern ac/ac power converter technologies and demands of industries have reached beyond standard ac/ac power converters with voltage-source inverters fed from diode rectifiers. Power electronics converters have been matured to stages toward compact realization, increased high-power handling capability, and improving utility interface. Modern ac/ac power converter topologies with various control strategies have been introduced for the further improvements, such as matrix converters, current-fed converters, PWM rectifiers, and active power filters. In this dissertation, several new converter topologies are proposed in conjunction with developed control schemes based on the modern ac/ac converters which enhance performance and solve the drawbacks of conventional converters. In this study, a new fault-tolerant PWM strategy is first proposed for matrix converters. The added fault-tolerant scheme would strengthen the matrix converter technology for aerospace and military applications. A modulation strategy is developed to reshape output currents for continuous operation, against fault occurrence in matrix converter drives. This study designs a hybrid, high-performance ac/ac power converter for high power applications, based on a high-power load commutated inverter and a mediumpower voltage source inverter. Natural commutation of the load commutated inverter is actively controlled by the voltage source inverter. In addition, the developed hybrid system ensures sinusoidal output current/voltage waveforms and fast dynamic response in high power areas. A new topology and control scheme for a six-step current source inverter is proposed. The proposed topology utilizes a small voltage source inverter, to turn off main thyristor switches, transfer reactive load energy, and limit peak voltages across loads. The proposed topology maximizes benefits of the constituent converters: highpower handling capability of large thyristor-based current source inverters as well as fast and easy control of small voltage source inverters. This study analyzes, compares, and evaluates two topologies for unity power factor and multiple ac/ac power conversions. Theoretical analyses and comparisons of the two topologies, grounded on mathematical approaches, are presented from the standpoint of converter kVA ratings, dc-link voltage requirements, switch ratings, semiconductor losses, and reactive component sizes. Analysis, simulation, and experimental results are detailed for each proposed topology.

Ce travail décrit une approche hybride couplant le procédé de dépôt chimique en phase vapeur assistée par plasma (PECVD) avec l’injection d’une solution colloïdale fabriquée au laboratoire pour la synthèse de films inorganiques nanocomposites (NC) incluant des nanoparticules de TiO2 (NPs) dans une matrice SiO2. Deux études préliminaires ont été réalisées en utilisant les deux méthodes classiques de dépôt : enduction centrifuge et PECVD. La première nous a permis de mieux comprendre les interactions des NPs de TiO2 avec un plasma O2 à basse pression (3m Torr) et la seconde d’élucider la nature de l'interface entre les NPs cristallines et la silice amorphe préparée par PECVD. Pour l'approche hybride en une étape, tout d'abord, l'optimisation de la procédure d'injection des NPs de TiO2 dans un plasma O2 basse pression a été mise en oeuvre. Il a été démontré par calcul et prouvé expérimentalement que les principaux paramètres prolongeant la durée de vie des gouttelettes de solution colloïdale (ce qui peut induire des hétérogénéités du film et une pollution dans le réacteur) sont la volatilité du solvant, la géométrie du système, les espèces de plasma et la température entourant les gouttelettes. Ensuite, les nanocomposites ont été préparés en injectant simultanément des NPs de TiO2 dans le plasma O2- hexaméthyldisiloxane (HMDSO) comme précurseur d'une matrice de silice inorganique. Dans l'ensemble, la structure anatase et la taille des NPs de TiO2 sont conservées dans le film NC. En faisant varier les paramètres d'injection, il a été montré que, dans la matrice SiO2, qui est de bonne qualité optique, la teneur en NPs peut être réglée de 1 à 50% conduisant à des propriétés optiques ajustables
With the present work we propose a hybrid approach coupling the Plasma Enhanced Chemical Vapor Deposition (PECVD) process with injection of lab-made colloidal solution for the synthesis of inorganic TiO2-SiO2 nanocomposite (NC) films. Two preliminary studies were carried out using the conventional deposition methods: spin coating and PECVD. The first one allowed us to gain insights on the low O2 plasma – NPs interactions and the second one on the nature of the interface between the crystalline NPs and the amorphous PECVD SiO2. For the one-step hybrid approach, first, the optimization of the injection procedure of TiO2 NPs in an O2 lowpressure plasma was implemented. It was shown computationally and proven experimentally that the main parameters prolonging the lifetime of the solution droplets (causing heterogeneities in the film and pollution in the reactor) is the solvent volatility, the system geometry, the plasma species and the temperature surrounding the droplets. Second, the nanocomposites were prepared by simultaneously injecting TiO2 NPs into the O2-hexamethyldisiloxane (HMDSO) plasma leading to a inorganic silica matrix of optical quality. In the overall, both the anatase structure and the 3 nm size of the TiO2 NPs were retained in the NC film. By varying the injection parameters, it was shown that the anatase NP content in the SiO2 matrix can be tuned from 1 to 50% leading to adjustable optical properties

La thèse porte sur cette couche de nitrure ou d’oxynitrure de silicium. Le déroulé prévoit l’élaboration des deux types de dépôts par voie gazeuse (par Chemical Vapor Infiltration CVI), la caractérisation de ces dépôts (par tous les moyens scientifiques à disposition et jugés utiles), ainsi que des essais en conditions proches de l’application visée (haute température, présence de phases liquides) pour juger de l’efficacité de ces dépôts et notamment effectuer une comparaison entre le nitrure et l’oxynitrure. Une étude complète des paramètres modifiables lors de l’élaboration et de leur effet sur la chimie (et par conséquent l’influence sur le comportement du matériau en conditions d’utilisation) représente le cœur du travail considéré
Ceramics are usually used at high temperature because of their refractory nature. However, they are too brittle to be submitted to high stresses, such as in the rotating parts of aircraft engines. One way to reduce the brittleness of ceramics is to design them as composites. The fiber/matrix architecture displays a damageable character thanks to a suitable interfacial layer, which is deposited on the fiber cloths before the infiltration with molten silicon. The aim of the thesis is to propose and evaluate a solution to protect the fiber reinforcement during the impregnation step with liquid silicon. This solution involves the deposition of a protective layer made of silicon nitride or oxynitride

Les dispositifs symétriques à lignes microélectroniques annulaires à six accès sont analysés par la méthode de superposition de modes pair et impair. Une autre méthode d'analyse est aussi développée. Elle permet de déterminer les matrices [S] de coupleurs anulaires (anneaux) symétriques ou asymétriques à N accès. Les coupleurs 6,6,1 et 6,8,1, qui sont des circuits à six accès composés respectivement de 6 et de 8 tronçons de lignes γ/4, ayant une impédance caractéristique, sont exploités dans deux applications. L'anneau 6,6,1 est utilisé comme un coupleur unique dans un modulateur à huit états de phase. L'anneau 6,8,1 qui est en effet un coupleur hybride 90°, 180°, 270°-6dB est utilisé comme le circuit principal d'un analyseur de réseaux microondes. Les dispositifs composés de plusieurs impédances caractéristiques (anneaux 6,6,2 et 6,8,2) sont étudiés dans le but d'obtenir des coupleurs à large bande.

Det finns olika tekniska lösningar för hantering, transport och återvinning av plastindustrins spillmaterial, men vilken metod som är mest lämpad för en specifik industri är svårt att avgöra. Syftet med studien var att få ökad kunskap och förståelse för hur faktorer som arbetsmiljöpåverkan, miljöpåverkan, funktion, flödeseffektivitet och investeringskostnad påverkar val av transportlösning för spillmaterial. Baserat på dessa faktorer är studiens mål att genom en förstudie presentera ett beslutsunderlag för en eventuell investering. För att finna den mest lämpade transportlösningen och förstå det grundläggande problemet med det nuvarande systemet genomfördes en nulägesanalys på fallföretaget. Informationen låg senare till grund när en undersökning av olika lösningsalternativ på marknaden gjordes. För att urskilja de mer relevanta alternativen för fallföretaget användes en kravspecifikation samt Kanomodellen. När de relevanta lösningarna valts ut jämfördes dessa mot varandra genom en QFD-matris för identifiering av den mest lämpliga transportlösningen. Resultatet av studien indikerade genom en QFD-matris att det manuella systemet var att föredra för fallföretaget.

L'objet de ce memoire porte sur la cristallisation dans le systeme quaternaire, cao-bao-al2o3-sio2 (bcas) afin d'elaborer une matrice vitroceramique renforcee par un renfort de type sic. Le domaine de composition choisi permet la cristallisation en proportion variable de deux phases majoritaires, le celsian monoclinique baal2sio8 ( = 2,3 10-6c-1) et l'anorthite triclinique caal2sio8 ( = 4,5 10-6c-1) ce qui permet d'adapter le coefficient de dilatation thermique de la matrice a celui du renfort et ainsi d'intervenir sur la tenue mecanique du composite. De plus, cette matrice tres refractaire doit conferer au composite une temperature d'application tres elevee (t 1300c). On a d'abord montre que la formation de la phase celsian, impossible dans le systeme bas pur, est favorisee pour des compositions riches en cao. Lorsque la proportion de bao augmente, la quantite de celsian s'accroit jusqu'a une composition bao/(cao + bao) = 0,5 pour laquelle la phase hexacelsian metastable ( = 8 10-6c-1) cristallise preferentiellement au celsian. Cette evolution cree un minimum pour le coefficient de dilatation thermique de la vitroceramiques ( = 4. 10-6c-1) et s'accompagne en parallele de modification microstructurales independantes de la nature des phases cristallisees. Ensuite, la densification de ces matrices est possible a basse temperature (t 930c), entre les temperatures de transition vitreuse et de cristallisation (porosite ouverte < 1%). Elle est encore amelioree par l'addition de certains oxydes, notamment b2o3 et la2o3, sans alterer la nature des phases cristallisees. Enfin, la matrice de composition bao/(cao + bao) = 0,33 presentant le plus faible coefficient de dilatation thermique et une bonne aptitude a la densification a permis d'elaborer un composite a fibres longues sic(o) avec une porosite inferieure a 1%. La presence des fibres favorise la cristallisation de la phase celsian au detriment de celle d'anorthite.

The final thesis is focused on a process management in praxes. The theoretical part of thesis concludes different techniques of mapping and analysing of a process. The practical part is focused on a practical analyse and mapping of the certain process in international financial institution. On the base of the process analyse are suggested changes to optimize the process.

A new method, probability distribution of diffusivities (time scaled square displacements between succeeding video frames), was developed to analyze single molecule tracking (SMT) experiments. This method was then applied to SMT experiments on ultrathin liquid tetrakis(2-ethylhexoxy)silane (TEHOS) films on Si wafer with 100 nm thermally grown oxide, and on thin semectic liquid crystal films. Spatial maps of diffusivities from SMT experiments on 220 nm thick semectic liquid crystal films reveal structure related dynamics. The SMT experiments on ultrathin TEHOS films were complemented by fluorescence correlation spectroscopy (FCS). The observed strongly heterogeneous single molecule dynamics within those films can be explained by a three-layer model consisting of (i) dye molecules adsorbed to the substrate, (ii) slowly diffusing molecules in the laterally heterogeneous near-surface region of 1 - 2 molecular diameters, and (iii) freely diffusing dye molecules in the upper region of the film. FCS and SMT experiments reveal a strong influence of substrate heterogeneity on SM dynamics. Thereby chemisorption to substrate surface silanols plays an important role. Vertical mean first passage times (mfpt) in those films are below 1 µs. This appears as fast component in FCS autocorrelation curves, which further contain a contribution from lateral diffusion and from adsorption events. Therefore, the FCS curves are approximated by a tri-component function, which contains an exponential term related to the mfpt, the correlation function for translational diffusion and a stretched exponential term for the broad distribution of adsorption events. Lateral diffusion coefficients obtained by FCS on 10 nm thick TEHOS films, thereby, are effective diffusion coefficients from dye transients in the focal area. They strongly depend on the substrate heterogeneity. Variation of the frame times for the acquisition of SMT experiments in steps of 20 ms from 20 ms to 200 ms revealed a strong dependence of the corresponding probability distributions of diffusivities on time, in particular in the range between 20 ms and 100 ms. This points to average dwell times of the dye molecules in at least one type of the heterogeneous regions (e.g. on and above silanol clusters) in the range of few tens of milliseconds. Furthermore, time series of SM spectra from Nile Red in 25 nm thick poly-n-alkyl-methacrylate (PnAMA) films were studied. In analogy to translational diffusion, spectral diffusion (shifts in energetic positions of SM spectra) can be studied by probability distributions of spectral diffusivities, i.e. time scaled square energetic displacements. Simulations were run and analyzed to study contributions from noise and fitting uncertainty to spectral diffusion. Furthermore the effect of spectral jumps during acquisition of a SM spectrum was investigated. Probability distributions of spectral diffusivites of Nile Red probing vitreous PnAMA films reveal a two-level system. In contrast, such probability distributions obtained from Nile Red within a 25 nm thick poly-n-butylmethacrylate film around glass transition and in the melt state, display larger spectral jumps. Moreover, for longer alkyl side chains a solvent shift to higher energies is observed, which supports the idea of nanophase separation within those polymers.

Il presente lavoro di tesi ha come obiettivo principale lo studio di materiali innovativi per lo sviluppo di componenti ottici nella regione spettrale dell’estremo ultravioletto (EUV) e dell’ultravioletto da vuoto (VUV). I campi di applicazione sono molteplici e spaziano dalla litografia EUV all’esplorazione spaziale. Questo tipo di ricerca richiede contemporaneamente l’utilizzo e la messa a punto di adeguati metodi di caratterizzazione, che permettano una completa analisi delle proprietà nella regione spettrale di interesse. Il risultato più interessante presentato è sicuramente l’analisi ottica e strutturale di strati di grafene (singolo e triplo) depositati su silicon oxide, nella regione spettrale dell’ultravioletto da vuoto. Lo studio è stato affrontato combinando diverse tecniche sperimentali e partendo dalle proprietà ottiche dell’ossido di silicio depositato su silicio (SiO2/Si), che costituisce il substrato. Il SiO2/Si è stato caratterizzato alla hydrogen Lyman-alpha (121.6 nm) utilizzando un riflettometro dedicato alla riflettometria nell’ultravioletto e recentemente implementato per misure polarimetriche (CNR-IFN Padova). Sono stati determinati i parametri ellissometrici, ratio (ρ) and phase shift (), le costanti ottiche e le proprietà polarimetriche del silicon oxide. Il SiO2 si comporta effettivamente come una lamina di ritardo introducendo una differenza di fase tra le componenti s- e p- della radiazione incidente. La differenza di fase introdotta varia dai 18° ai 160° e dipende dall’angolo di incidenza. Successivamente, lo stesso tipo di analisi sperimentale è stata completata per i campioni con uno strato di grafene depositato sull’ossido di silicio (1LG/SiO2/Si). E’ stato osservato che, nonostante il sottile spessore, il singolo strato di grafene migliora la riflettività del substrato. Dall’analisi polarimetrica, non si può invece affermare che il grafene introduca un ritardo di fase osservabile. Le costanti ottiche del singolo e triplo strato di graphene cresciuto su SiO2/Si sono state studiate alla hydrogen Lyman-alpha utilizzando misure in riflettometria in polarizzazione s- e p- acquisite utilizzando luce di sincrotrone (ELETTRA Trieste, BEAR beamline). Si notano differenze misurabile nella riflettività dei campioni. Le differenze dipendono dal numero di strati di graphene. Queste misure sono state utilizzate per ricavare le costanti ottiche. E’ stata inoltre sperimentalmente osservato una anisotropia ottica con asse di simmetria quasi perpendicolare alla superficie e coerentemente correlata all’orientamento degli orbitali π. Le costanti ottiche efficaci sono state ricavate simulando l’interazione della radiazione elettromagnetica con la struttura del campione. Inoltre, l’attendibilità delle costanti ottiche trovate è stata qualitativamente testata ricavando la “surface differential reflectance (SDR)” dalle misure di riflettività. Un altro effetto molto interessante indotto dal grafene è lo spostamento dell’angolo di pseudo-Brewster rispetto a quanto osservato per il substrato. Lo spostamento, che cresce in valore assoluto con il numero di strati, induce un downshift contrariamente a quanto osservato in altre regioni spettrali. La qualità della superficie, la morfologia e il numero di layer sono stati caratterizzati con misure di microscopia a forza atomica e spettroscopia Raman. Per quanto ne sappiamo, questi risultati relativi allo studio delle proprietà ottiche del grafene nel VUV sono assolutamente nuovi. L’ultima parte della tesi riguarda lo studio dello strato di stagnazione che si forma sul fronte di collisione di due plasmi collidenti. La tecnica utilizzata è una spettroscopia risolta in tempo. Il tempo di evoluzione e le dinamiche dei plasmi collidenti di Al-Al e Al-Si sono stati studiati con tecniche spettroscopiche risolte in tempo. È stato osservato che nel caso di un "wedge target" lo strato di ristagno produce uno spettro più luminoso e in precedenza sono comparsi stati di ionizzazione più elevati con un'intensità relativamente più elevata di un "flat target". Il tempo di evoluzione della densità elettronica è stato studiato e confrontato nel caso delle due configurazioni con i target diversi e una densità elettronica relativamente più alta è stata osservata nel caso di “wedge target”.
The aim of this research is to investigate and explore new innovative material(s) and techniques regarding development and improvement of vacuum ultraviolet (VUV) and extreme ultraviolet (EUV) optics and sources; for the advancement of EUV and VUV technological areas like space exploration (e.g. observation and spectroscopic diagnostics of the solar corona) and EUV lithography (e.g. advancement and minimization of integrated electronic circuits (ICs)). The research work was primarily focused on the investigations of the optical and structural properties of graphene (mono and few-layer) deposited on SiO2/Si substrate in VUV spectral region by exploiting different diagnostic techniques, based on reflection and polarimetric measurements. The study was addressed starting from silicon dioxide deposited on silicon (SiO2 / Si), which works as the substrate for graphene samples. The optical properties of SiO2/Si were thoroughly investigated at the hydrogen Lyman–alpha line (121.6 nm) by employing the tabletop EUV-VUV polarimetry facility located at CNR-INF Padova. An approach based on the combined use of reflectometry with polarimetry technique was used to find out the reliable values of the optical constants. The results show the potential of the approach and it was demonstrated in this study that the optical constants retrieved by using ellipsometric parameters; ratio (ρ), and phase shift (), are more reliable than the retrieved one using least square fitting of the reflectivity. Moreover, it was found that SiO2 behaves as a phase retarder by introducing a phase difference between the s- and p- polarization components of the incoming light. The phase differences observed was 18° to 160° depending on the incidence angle. Using the similar experimental technique, the ellipsometric parameters (phase shift (ϕ), ratio (ρ)) of graphene (1LG/SiO2/Si) sample were also investigated and compared with that of SiO2/Si to see the effect of the graphene as capping layer. It was found that 1LG on top of SiO2 improves optical throughput and despite having atomic thickness it affects the polarimetric properties of the underlying substrate. Further, detailed optical properties of mono (1L) and tri-layer (3L) of commercial graphene grown on (SiO2/Si) substrate were studied at hydrogen Lyman alpha by using laboratory based (at CNR-IFN, Padova) and synchrotron light-based (at BEAR beamline, Elettra synchrotron) EUV-VUV reflectometer setups. Angular reflectance measurements of graphene samples along with bare substrate were performed by taking into account the light polarization. Distinguishable optical performance was observed for both samples (1LG and 3LG) in spite of the ultra-thin thickness of the films. Optical anisotropy with the axis of symmetry nearly perpendicular to the surface and coherently related to the p-orbitals structural orientation has been experimentally demonstrated. Anisotropic “effective optical constants” corresponding to “effective thickness” were retrieved by simulating the interaction of the electromagnetic wave with the structure of the sample. Furthermore, the reliability of the derived optical constants was tested qualitatively by deducing surface differential reflectance (SDR) from the reflectance measurements. Another very interesting effect induced by graphene is the shift of the pseudo-Brewster angle with respect to what was observed for the substrate. The downshift of the pseudo-Brewster angle was observed for both samples 1LG (-1.5°), and 3LG (-5°), with larger shift for an increasing number of layers. However, in literature an upshift in the Brewster angle is reported but for different spectral region. AFM, XPS and Raman spectroscopies were used to study surface morphology, quality of graphene coatings, and to estimate the thickness/ number of layers. To the best of our knowledge, these remarkable optical properties of graphene at VUV spectral region was determined for the first time and results are of considerable interest for VUV optics advancement. The last part of the thesis is about the study of the stagnation layer formed at the collision front of two colliding plasmas by employing time resolved spectroscopic technique. Time evolution and dynamics of the Al-Al, Al-Si colliding plasmas studied and compared in the case of flat and wedge targets. It was observed that in case of wedge target the overall emission from stagnation layer was more intense and higher ionization states of (Al and Si) appeared earlier in time having higher intensity compared to the flat target. The time evolution of the electron number density was also studied and it was observed that wedge target results in a relatively higher electron number density

L'elaborato espone il contributo del candidato nel processo di elaborazione di una tecnica innovativa per il miglioramento dei metodi di assemblaggio e collaudo di MU-CN. Il modello sarà di riferimento per l’analisi delle attività a valore e spreco per tutto il gruppo aziendale. Facendo riferimento alle legioni romane: la tecnica vuole prima di tutto strutturare la strategia di attacco ovvero dichiarare come dovrebbero muoversi le legioni, poi enunciare ai singoli soldati (industrializzatori/ progettisti) come deve essere usata la spada (strumenti) ed infine quali delle spade a disposizione servono per l’attacco in questione. Il progetto parte da uno studio di benchmarking delle best practice nel settore machinery, per poi convergere nell’approfondimento di un sistema di analisi adattato al background aziendale. Si utilizzeranno strumenti quali il Design for Assembly e l’Approccio Scientifico. Questi saranno i 2 approcci fondamentali con cui si procederà alla generazione di un nuovo metodo per le attività esecutive. Inoltre, in termini di completezza di analisi si investirà anche il processo di sviluppo nuovo prodotto, cercando di anticipare il più possibile (front-loading&concurrent engineering) la rilevazione delle inefficienze. Infine, vi sarà il supporto del candidato nell’istituzionalizzazione del nuovo metodo, nella conduzione di attività d’implementazione pilota e nell’elaborazione dei piani di roll-out che lo vedranno in veste di trainer insieme al Team di Progetto. I risultati ottenuti sono stati soddisfacenti, perciò la tecnica proposta avrà riscontro reale e verrà implementata nel Gruppo entro fine 2018. In particolare, si sono incrementati i rendimenti medi delle linee osservate e ridotti i costi di assemblaggio e struttura dei pezzi analizzati, dati stimati grossolanamente grazie all’applicazione pilota della nuova tecnica.

碩士
國立清華大學
核子工程與科學研究所
104
In recent years, gold (Au) nanoparticles have been synthesized by means of various methods and have received promising potential in optical and biomedical detection. Au nanoparticles contain some remarkable dimension-dependent optical properties due to surface plasmon resonance (SPR) in Au nanoparticles which causes strong absorption of the incident light in visible light regions. Since SPR in well-crystallized Au nanoparticles can enhance the local electromagnetic field, it is thus expected that a greater efficiency in the photoluminescence (PL), originating from oxygen deficiency centers (ODC), can be achieved in Au-implanted SiO2 matrix. In order to demonstrate the enhancement of PL, in this story, Au nanoparticles were formed in SiO2 film using ion beam synthesis and their optical and microstructural properties were also investigated as well. The results revealed that a clear absorption peak at approximately 520 nm was identified in the UV-Vis spectra and was attributed to SPR induced by Au nanoparticles in SiO2 film. The SPR of Au nanoparticles is also dependent on thermal treatment conditions, such as annealing gas, annealing temperature and annealing time. The Au nanoparticle-containing SiO2 film also displayed several distinctive peaks at approximately 310, 380, 450, and 600 nm in the PL spectra and were found to be associated with ODC-related defects and non-bridging oxygen hole centers (NBOHC) in SiO2 film. In addition, the PL peak intensities increase as annealing temperature increase, a finding contradictory to the defect recovery. The greatest PL emission was achieved when the Au-implanted SiO2 film was annealed at 1100 oC for 1 h under the nitrogen ambient. Therefore, the existence of Au nanoparticles in SiO2 film can induce SPR effects and enhance PL emission which was mainly due to defect dependent luminescence centers.

碩士
國立中正大學
化學研究所
89
We have fabricated colloidal Au nanorods via electrochemical method and they are embedded in a thin layer of silica with uneven thickness. The sol-gel process is responsible for the production of such core-shell nanostructure, AuNanorod@SiO2. The sol-gel material is not only porous and transparent but also electrically insulating. It can mimic the shielding layer of a bulk conducting wire. Furthermore, taking advantage of the characters of the sol-gel, we can further put additional function onto the Au nanorod particles via surface modification and turn them into multifunctioned nanocomposites. The context in this thesis is focused on the optical responses of the Au nanorods before, during and after the surface modification. Also, the second subject is to investigate how the shell structure influences the shape transitions of the core Au nanorod during a photoannealing process. It turns out to be a sensitive and perfect system to unravel the matrix effect of photoannealing for AuNanorod@SiO2 particles. The core-shell nanostructures of AuNanorod@SiO2 with uneven thickness of silica are demonstrated successfully to comprise a couple of coating processes: the coating of an adapting layer of MPTMS (3-mercaptopropyltrimethoxy silane) and the coating of shell silica via a hydrolysis and condensation of siloxane precursor, TEOS. The single particle coating is then completed. Adjusting the pH value during the second process and the reaction time allow us not only carefully control the geometric shell structure but also the shell thickness. The cladding along the long axis is much thinner relative to the thickness along the short axis. The studies on the matrix effect of photoannealing were conducted by irradiating the core-shell nanoparticles by either 532 nm or 1064 nm. The former excites the transverse surface plasmon of the embedded Au nanorod and the later cause the excitation of the longitudinal surface plasmon. The experimental results reveal that the excitation of long axis surface plasmon on the particles with 12 hrs coating time gives much higher yields of the fission products, 2-sphere@SiO2. In addition, the shape transformed products of the photoannealing process for particles with relatively high aspect ratios include a unique structure of 3-sphere@SiO2. We have summarized the results regarding the photo-induced shape transition of the Au nanorod@SiO2 and demonstrate clearly the effect of the heat release within the shell structures. The unequal heat release rates along the major and minor axis influence the particle shape transformation sensitively.

碩士
國立中山大學
物理學系研究所
101
Transitional metal oxide nanoparticles (doping 0.5 mole %) embedded in a silica glass using the sol-gel method with different annealing temperatures. For iron-oxide nanoparticles system. An interesting colossal enhancement of dielectric constant is observed around room temperature with diffuse phase transition due to the thermally activated oxygen vacancies. In addition, there is a feature observed near 65 K due to ferroelectric effect. The magnetodielectric effect observed in the glass composite is considered to be affected by magnetoresistance changes. For polarization study, we observed a transition temperature near 65 K. It is interesting to observe multiferroic phenomena in amorphous material. The characteristics of nano-magnetic iron-oxide particles were determined respectively with various techniques, such as XRD, TEM, and XANES. For cupric-oxide nanoparticles system. There is a coexistent feature observed near 250 K from magnetic and dielectric study. From magnetodielectric study, we observed this system shows a negative magnetodielectric effect.

碩士
中原大學
工業與系統工程研究所
105
This thesis improves the process capability of high-resolution products of color filter factory. By the Six Sigma Methodology which follows the steps including define, measure, analyze, improve, and control, the Black Matrix Process of Color Filter process capability is thus enhanced. Firstly, the key quality characteristics are defined and the accuracy of the measurement system is confirmed. Then, the key factors which affect the quality characteristics are found. Finally, L8 orthogonal table from Taguchi method is applied to reduce experimental times and the optimal parameters via Taguchi’s two-stage optimization are found. The experimental results showed that after the improvement of the optimal parameters, we can make high-resolution products with the black matrix line width stability in the 7 ± 1.5μm range and the Black matrix process capability index improvement from 1.38 to 1.89 that is better than the expected value (Cpk > 1.67). The experimental results showed that the method improves the black matrix process capability effectively.

碩士
國立成功大學
電機工程學系
102
In recent years, with labor costs in developing countries rapidly increasing and a trend in the manufacturing industry of moving back to America and Europe, the topic of automation has once again become a hot issue. In the meantime, the growing trend of customized “small-volume large-variety production” indicates that the flexibility of production line is more critical than ever. Nowadays, surface machining applications account for about one-third of applications in industrial robots. In this field, if a 3D geometry model of objects for machining cannot be obtained in advance, trajectory planning will be achieved only with much difficulty and the machining precision will be diminished. Conventionally, teach-by-showing is a solution, but it is time-consuming and the results are limited. Although laser-based inverse engineering approaches are available, generally these approaches are complicated and their costs are high. Therefore, this thesis plans to integrate the stereo vision into industrial robots to solve those problems. However, it is doubtless that most objects for machining have few features, so traditional stereo matching algorithms will fall short in reconstructing the 3D models of these objects. In order to deal with the aforementioned problem, this thesis develops a homography based stereo matching algorithm. Firstly, this thesis increases the number of features on objects for machining by combining several algorithms and then filters out the miss matches. Based on the correct matches, a robust homography matrix is estimated. Moreover, the stereo matching result is calculated through this matrix. Consequently, depth estimation and 3D reconstruction will be conducted. Several experiments have been conducted to assess the performance of the proposed approach. In the experiment, the reconstructed 3D model is used in a surface machining task performed by a six-axis articulated robot. Experimental results indicate that the approach proposed in this thesis provides good reconstructed results so as to verify the effectiveness of the proposed approach in surface machining.

碩士
國立中山大學
機械與機電工程學系研究所
106
This study developed a six-axis force/torque sensor and a calibration system. In order to improve the stability of the calibration system, we used VCMs (voice coil motor) as the output force device of the system. Simply and directly structures designed also make the six-axis calibration force/torque much more reliable. Furthermore, the system combined two precise one-axis load cells to receive the output reactionary force from VCMs, then used the proportional-integral-derivative controller (PID controller) to reduce the steady-state time. Finally, there are some mechanism designed to adjust the orientation of the calibration force. The principle of the six-axis force/torque sensor is the mechanical deformation of the structure and we use the resistance strain gauges as the measuring devices because of the characteristic of wide measuring range and high level accuracy. According to the results of strain analysis using ANSYS, we designed a crab-type force sensor as the main structure of our sensor. By measuring the strain gauges on the elastic body surfaces, we get the corresponding voltages by each applied calibration force. In this study, we conduce LSE (Least squares estimation) and MLE (Maximum Likelihood Estimation) to find the transfer function between the calibration force/torque and the voltages of the sensor. On the whole, we integrated the whole system with LabVIEW and also simplified the usage of this equipment in order to minimize the operation error. The six-axis calibration process has been conducted to verify the proposed method.

碩士
國立中正大學
電機工程所
96
In this thesis work, a miniaturized CMOS hybrid is studied and implemented in the related circuits. By using the transformer-based model and compensatory capacitor, the phase error caused by substrate loss can be compensated, and the chip size can be dramatically reduced. The miniaturized hybrids, which are realized by lump elements using 0.18-

碩士
明新科技大學
工業工程與管理系碩士在職專班
103
In the global competitive environment, major companies dedicated to compressing its manufacture time and produce the new products meeting the demand. Therefore,its very important to meet the customers need by reducing defect factors rate to make the production more efficient, And proceeding risk planning and management of the overall product development system to prevent potential failure occurs to reduce the unsure factors. This study was based on Six Sigma DMAIC improvement practices, using a black matrix color filter process common defect rate as a case study. Firstly processing clean room airflow assessment as a basis for selecting projects, and then using Six Sigma improvement techniques to be standard criteria of improving common defect rate. Discussion by periodic assessment Six Sigma improvement techniques, to identify key quality characteristics values (Define),measure the accuracy of the measurement system of the (Measure) to summarized the key factors affect the process of production. And then make use of experimental design experiments to test method to find out impact factor (Analysis) to verify process capability of machine to reduce the defect rate of producing production (improve), and list the best machine capability standard as control items (control).

碩士
逢甲大學
經營管理碩士在職專班
100
Color Filter is the key component of the TFT-LCD, and around 19% of the total cost of accounting for materials, is the main factor to colorize the liquid crystal display. Due to cost considerations, most of panel makers have their own color filter factory in order to reduce production cost, even though partially outsourcing to ensure steady supply of CF. The lithography process implements the new process PSA to simplify the wide viewing angle of the process and results in MVA process production lines, which can be used to manufacture RGB color layer and photo spacer process instead. This also leads the black matrix process production lines becoming the productivity bottleneck in factory. By using Lean Six Sigma Tools (DMAIC) to identify the key factors of tact time, this study finds the bottleneck equipment of the black matrix process in production line and further to optimize it. The black matrix production line tact time is improved from 40.8 sec to 39 sec. This increases the 2.4K monthly capacity and reduces the purchase cost of approximately $106 million dollars by final conversion effectiveness. Furthermore, this leads to increase the rate of in house supply and reduce the outsourcing costs, thereby reduce the production costs and improve the company''s competitiveness.

Esta nota pretende dar a conhecer resumidamente de que maneira foi organizado este trabalho para cumprir os objectivos que nos proposemos realizar. Como se pode verificar com mais detalhe nos Objectivos do trabalho (ver índice, página ii), pretendia-se sinterizar sem pressão e a baixa temperatura o niíreto de silício (Si3N4) e um material compósito, constituído por uma matriz, também de Si3N4, e uma fase dispersa de carboneto de silício (fase de reforço) com a forma de fibrilas (compósitos que designamos Si3Nd/SiCf). Como se pode observar no Índice (página ii), esta tese esta subdividida em seis partes fundamentais que se iniciam com a Introdução (parte 1.1) a que se seguem a Revisão de . assuntos (parte LI), os Objectivos do trabalho (parte 1.2), a Realização experimental e resultados (parte II), a Discussão dos resultados e conclusões (parte 111) e por último a Bibliografia.
Programa Doutoral em Engenharia dos Materiais

碩士
國立中興大學
化學系
87
ABSTRACT Part I. Microstructural and Morphological Characteristics of PS-SiO2 Nanocomposites A series of organic-inorganic hybrid materials have been prepared by copolymerizing styrene and alkoxysilane-methacrylate via sol-gel process. The alkoxysilane-containing copolymer precursors were synthesized by free-radical copolymerization of styrene with an alkoxysilane-containing monomer, methacrylic acid 3-(trimethoxysilyl)propyl ester (MAMSE), at several feeds. The copolymer precursors were then hydrolyzed and condensed to generate PS-SiO2 hybrid sol-gel materials. The hybrid copolymers possess excellent optical transparency and a nanoscale microphase separation. The copolymer precursors and their hybrid copolymers were characterized by FTIR spectra, 1H-NMR spectra, DSC, and TGA thermograms. Chemical structural effect on the morphology and thermal properties was investigated with SEM, mapping photographs, and high-resolution solid state 13C- and 29Si-NMR spectra. It is found that compatibility between copolymer and silica mainly contributes from incorporating the polymer with silica covalently. Moreover, MAMSE could be hydrolyzed to methacrylic acid and ester-interchanged to silyl methacrylate during heat treatment. This also enhances compatibility between copolymer and silica. Thermal properties of PS-SiO2 hybrid copolymers are improved as silica content increase. However, the presence of silyl ester groups, which were formed during heat treatment, would reduce thermal stability of the hybrid copolymers. Part II. Synthesis and Optical Properties in the Sol-Gel Matrix Bearing an Azobenzene Chromophores. A series of NLO chromophores with several types of spacers have been synthesized. The chromophores were incorporated with melamine-based polymers by sol-gel process to form soluble prepolymers. Excellent optical transparency and large second-order nonlinearities of up to 28 pm/V have been determined afer poling and curing process. Morphological and temporal characteristics were investigated by SEM photograph, relaxation dynamic and temporal relaxation behaviors. Moreover, the relaxation data have been fitted with KWW equation and Arrhenius equation. In morphological characteristics, It is found that compatibility between chromophores and melamine-based polymers can be enhanced by covalently incorporating the polymer with chromophore by a flexible spacer. In the study, no macroscopic phase separation could be observed even the chromophore content of HHAN/melamine system of up to 30 %. In relaxation dynamic, slow relaxation behavior observed at the temperature at or above effective relaxation temperature, T0, mainly contribute from restraint of the sol-gel network in the poled melamine-based NLO polymers. Alternately, high effective relaxation temperature, T0 = 83 ℃, of the HA1 polymer is dominated from an anchor effect cased by directly covalent bonding rigid chromophore into melamine system. In temporal relaxation behaviors, temperature of thermal aging process has a great effect on the relaxation behaviors. A slow variation of the SHG signal relaxation behavior can be observed at temperature below T0. This relaxation behavior depends on degree of cross-linking density. In the ASH polymer system, a more stable temporal stability was found, which mainly contributes from a more condensed network. In the systems, the relaxation data can be fitted by the Kohlrausch-Williams-Watts (KWW) stretched equation. A high characteristic relaxation time, τ = 9000 min, at room temperature and activation energy, Ea =100 KJ/mole, below effective relaxation temperature was found in the ASH polymer.