Tesis sobre el tema "Solution Combustion Synthesi"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 33 mejores tesis para su investigación sobre el tema "Solution Combustion Synthesi".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
MARIN, FIGUEREDO MIGUEL JOSE. "Metal Oxide Catalysts for the Abatement of Volatile Organic Compounds and Carbonaceous Particulate Matter". Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2966339.
Texto completoTopolski, Diogo Kramer. "Obtenção de espinélio MgAl2O4 nanoestruturado através de síntese contínua por combustão em solução". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/116606.
Texto completoThis study has investigated a continuous solution combustion synthesis technique to obtain the nanostructured MgAl2O4 spinel powder and their characterize them by different tecniques. This study has also included the investigation of the influence of different kinds of fuel and fuel-to-oxidant ratio on crystallite size. The MgAl2O4 spinel powder was performed using aluminum nitrate and magnesium nitrate to obtain the metallic ions. Urea, glycine and sucrose were used like fuel, with several fuel-to-oxidant ratio. These parameters were correlating with powders characteristics, like crystallite size, particle size and superficial area. The techniques used for powder characterization included differential thermal analyzer (DTA), thermogravimetric analyzer (TGA), particles size analyzer (PSA), surface area by BET analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The chemical reactions of solution combustion resulted on crystalline phase to the reactions with urea, glycine and sucrose (to desabilites on fuel and stoichiometric) and amorphous phase formation of MgAl2O4 in situ for as-synthesized powder. The crystalline phase formation of spinel MgAl2O4 was only succeeded obtained after a thermal treatment of as-synthesized powder under 900°C.The spinel MgAl2O4 powders obtained were composed of nano-size crystallites, but in micrometer-sized aggregates. The mean particle size calculated, via Single Line method, using XRD was 13 nm. PSA indicated that the synthesized powders contain a mean aggregates size with a tri mode distribution of around 17.1 μm. SEM analyses confirmed that the as-synthesized powders are composed of particles aggregation. They have an irregular morphology and nano-size crystallites.
Giangolini, Matteo. "Production and characterization of tin oxide thin films deposited via solution combustion synthesis". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15816/.
Texto completoNascimento, Cássia Costa. "Síntese de cerâmicas tipo perovskita com potencial uso em células solares". Universidade Federal de São Carlos, 2017. https://repositorio.ufscar.br/handle/ufscar/8819.
Texto completoApproved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-05T12:04:13Z (GMT) No. of bitstreams: 1 DissCCN.pdf: 6649361 bytes, checksum: 628a85415c5a65b4576d7a25bf144771 (MD5)
Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-06-05T12:04:20Z (GMT) No. of bitstreams: 1 DissCCN.pdf: 6649361 bytes, checksum: 628a85415c5a65b4576d7a25bf144771 (MD5)
Made available in DSpace on 2017-06-05T12:10:55Z (GMT). No. of bitstreams: 1 DissCCN.pdf: 6649361 bytes, checksum: 628a85415c5a65b4576d7a25bf144771 (MD5) Previous issue date: 2017-03-07
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Visible light accounts for the biggest fraction of the solar irradiance. One of the strategies for achieving higher photovoltaic power conversion efficiency is the application of low band-gap materials (Eg ideal≈1.4 eV) capable of absorbing this fraction of the solar spectrum. Ferroelectric semiconductors have been studied in this field due to the above-bandgap generated photovoltages and their ferroelectric polarization-driven carrier separation. Ferroelectric oxides usually present wide bandgaps which allow the absorption of only 8-20% of the solar spectrum. However, the development of new ferroelectric materials, particularly KBNNO [KNbO3]0,9[BaNi0,5Nb0,5O3-δ ]0,1 (Eg = 1.39 eV) and KBiFe2O5 (Eg=1,60 eV), has encouraged the use of such materials in solar cells. Simple synthesis routes, with short steps, time and temperatures are essential for the future progress of the application of such ferroelectric oxides in solar cells. KBNNO and KBiFe2O5 require high crystallization temperatures, which reduce the number of potential substrates and electrode materials that could be used in devices, as polymer-based flexible ones. Obtaining this oxides in a high surface-area powder form might be a strategy to further incorporation in solar cells composed of low-temperature processing materials. This work reports for the first time synthesis of KBNNO and KBiFe2O5 by solution combustion (SCS). Characterization by WAXD, SEM, EDS, TG/DSC and Diffuse Reflectance UV-Vis Spectroscopy and dielectric constants indicates the success of the synthesis. The optical properties show the visible-light absorption contribution and band-gaps closer to the ideal magnitude for solar applications compared to the non doped materials. The SCS was shown as an effective route to obtaining the phase. Furthermore, it is possible to improve it in order to produce powders with smaller particle size and absent of secondary phases.
A luz visível representa a fração mais relevante da radiação solar. Desta maneira, busca-se empregar nas camadas ativas das células solares materiais com baixos band-gaps (Eg ideal ≈1,4 eV), capazes de absorver fótons nessa região do espectro. Semicondutores ferroelétricos com estrutura da perovskita ou estruturas relacionadas têm sido estudados nesse campo devido ao potencial de obtenção de voltagens superiores à magnitude de seus band-gaps e à contribuição na separação de portadores de cargas decorrente da polarização intrínseca presente nesses materiais. Óxidos ferroelétricos geralmente possuem Eg elevados (2,7-4 eV), permitindo o aproveitamento de somente 8-20% do espectro solar. No entanto, o desenvolvimento de novos semicondutores ferroelétricos, particularmente a KBNNO [KNbO3]0,9[BaNi0,5Nb0,5O3-δ ]0,1 (Eg=1,39 eV) e KBiFe2O5 (Eg=1,60 eV), tem encorajado a aplicação desses materiais em células solares. Rotas de síntese simples, com etapas, tempos e temperaturas reduzidas são essenciais para o progresso futuro da aplicação de tais óxidos ferroelétricos em células solares. A KBNNO e KBiFe2O5 cristalizam em temperaturas mais elevadas do que perovskitas orgânico-inorgânicas, o que reduz a possibilidade de fabricação de dispositivos na presença de substratos e eletrodos sensíveis à temperatura, como substratos poliméricos flexíveis. Assim, a obtenção desses óxidos na forma de pós de elevada área superficial pode ser uma estratégia para posterior incorporação em dispositivos contendo materiais processados a baixas temperaturas. Neste trabalho, reporta-se pela primeira vez a síntese da KBNNO e KBiFe2O5 por combustão em solução. Caracterizações por DRX, MEV, EDS, TG/DSC, Espectroscopia UV-Vis e constantes dielétricas indicam a obtenção das fases com sucesso. As propriedades ópticas confirmam contribuição na absorção da luz visível com respeito aos materiais não dopados, KNbO3 e BiFeO3. A síntese por combustão em solução se mostra efetiva para obtenção das fases, mas passível de melhorias para produção de pós com menor tamanho de partícula e sem a presença de fases secundárias.
CNPq: 155305/2014-0
Toniolo, Juliano Cantarelli. "Influência da razão combustível-oxidante nas características de óxidos nanoestruturados sintetizados por combustão em solução". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/16479.
Texto completoWith the increasing use of solution combustion synthesis method for powder obtaining, there is a growing realization of the need to understand the unique characteristics of this process. This thesis presents the novel investigation of this technique specifically based upon some nanostructured powders such as α - Al2O3 (alumina), Cr2O3 (eskolite), α - Fe2O3 (hematite), Fe3O4 (magnetite), NiO (bunsenite), and CoO, Co3O4 (cobalt oxides) as a core option for future applications. These were characterized via DTA, BET, XRD, TEM, SEM, VSM, XPS, and FTIR. The particular focus of this work is based on the study of the fuel-to-oxidant ratio influence to the characteristics of the resulting materials. Other combustion parameters were identified and also proper appraised as flame type, temperature, gas generation, and chemical composition of precursor reagents. The thermodynamic calculation of the combustion reaction shows that as fuel-tooxidant ratio increases the amount of gas produced, and adiabatic flame temperature also increases. Powder characteristics as morphology, crystallite size, surface area and aggregation degree are mainly governed by the flame temperature, and generation of gases. The oxide and metals formation followed a thermodynamic behavior as expected, conform to Gibbs free energy. Lower crystallite sizes were always obtained by fuel-lean condition for all studied systems. The temperature was the main reaction parameter controlling the growth rate, while it competed with generation of gases to form crystallites under certain reducing conditions. The outcomes of this work have significantly improved the understanding of the fuelto- oxidant ratio effects on the behavior of the physical characteristics of powders. This correlation has been drawn in order to provide a knowledge basis for possible application of this technology to optimize or develop new powder systems.
Goujon, Pierre-Andre. "Synthèse par flash combustion et voie solide de formulations céramiques diélectriques dans le diagramme de phase ternaire CaO/ZrO2/TiO2". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMC225.
Texto completoThe compositional domain Ca(ZrxTi1-x)O3 has been studied in order to understand the formation of solid solution between CaTiO3 and CaZrO3. The aim of this study is the application of such formulations for multilayer ceramic capacitors with non-nobles metal armatures. The synthesis on the line CaTiO3/CaZrO3 is poorly known, either by solid state or by flash-combustion. The study and optimization (mixing/grinding, temperature of calcination) of the solid-state synthesis has allowed the synthesis of single-phase samples made of the perovskite phase along the whole compositional range. The study of the solution-combustion synthesis first determined that the most efficient fuel for the synthesis was glycine, then the fact that the titanium input allowing the formation of the purest phase is TiO(NO3)2, synthesized from titanium butoxide.The densification of the powders obtained by these two methods was studied and compared. These tests allowed to compare several parameters on the densification of the samples. These parameters are the powders’ method of elaboration, the Zr/Ti ratio and the sintering atmosphere. Sintering adds were also be tested on two compositions: CaZrO3 and Ca(Zr0.8Ti0.2)O3. These compositions have been chosen because they are weak in titanium, which avoids reduction and appearance of semi-conduction of Ti that would transform the capacitor into a p-semiconductor during sintering in a reducing atmosphere. This comparative study of these different parameters also deals with the dielectric properties of the samples thus produced
Pradal, Nathalie. "Synthèses, mise en forme et caractérisations de luminophores nanostructurés pour une nouvelle génération de dispositifs d'éclairage sans mercure". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00775908.
Texto completoVolkmer, Tiago Moreno. "Obtenção e caracterização de α-fosfato tricálcico por síntese de combustão e aplicação em cimentos ósseos e arcabouços de criogéis". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/34762.
Texto completoThe calcium phosphate cements have a large number of advantages regarding its use in orthopedics and traumatology, being the most prominent its biocompatibility and bioactivity, which allows the osteoconductive of bone tissue and in situ hardening, allowing greater ease of handling. However, the use of conventionals synthesis methods, e.g. solid state reactions, brings great difficulty to the obtainment of highly pure α- tricalcium phosphate phase. In this thesis, the use of the solution combustion synthesis method allowed to synthesize nanostructured α-tricalcium phosphate with high purity. Further studies on pHs influence, fuel natures (urea or glycine) and fuel ratio (0.75, 1.0, 1.5 and 2.0) allowed to define the best synthesis parameters (pH 1.5 and urea fuel content in two times higher than the stoichiometric). After choosing the best paramaters to the obtainment of higly pure α-tricalcium phosphate, we studied the feasibility of their use as calcium phosphate cement (CFC) by studing the influence of particle size by increasing the milling time from 30 to 180 minutes. The better results were found for the milling time of 180 minutes. Compressives strength of up to 30.4 Mpa were obtained for this formulation. However, after soaking the calcium phosphate cements in simulated blood plasma (SBF) in growing times up to 28 days, a decrease in the compressive strenght was noticed, which is an indicative of the high solubility of the α-tricalcium phosphate powders obtained by solution combustion synthesis. After the obtainment of the calcium phosphate cements, its application as bone substitute and as ceramic load in polymeric cryogels for use in tissue engineering were studied. Initially, the system dimethylaminoethyl methacrylate (DMAEMA) with 5% of an acrylic acid (acrylic acid or methacrylic acid) was used, but due its great instability and lack of reproductbility this system was abandoned. Since it has greater chemical stability and good mechanical properties, the monomer hydroxyethyl methacrylate (HEMA) was chosen as pair to the DMAEMA monomer. With the use of this polymeric system, porous scaffolds with porosity of up to 75% and pores up to 1 mm in diameter were obtained by the method of cryopolymerization. The addition of α-tricalcium phosphate to the porous scaffolds did not showed a significant influence on physical properties of the polymer network nether on mechanical properties of porous structures. However, it increased significantly the biocompatibility of the scaffolds, allowing the adhesion and proliferation of mesenchymal stem cells. The presence of type I collagen and alkaline phosphatase are good indicators that mesenchymal stem cells are differentiating into bone tissue and demonstrate the potential application of these materials as biomaterials, more specifically as bone substitutes.
SETZ, LUIZ F. G. "Processamento coloidal de cromito de lantanio". reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11522.
Texto completoMade available in DSpace on 2014-10-09T14:02:02Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Soares, Maria Rosa Nunes. "Development of Zirconia based phosphors for application in lighting and as luminescent bioprobes". Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/15884.
Texto completoThe strong progress evidenced in photonic and optoelectronic areas, accompanied by an exponential development in the nanoscience and nanotechnology, gave rise to an increasing demand for efficient luminescent materials with more and more exigent characteristics. In this field, wide band gap hosts doped with lanthanide ions represent a class of luminescent materials with a strong technological importance. Within wide band gap material, zirconia owns a combination of physical and chemical properties that potentiate it as an excellent host for the aforementioned ions, envisaging its use in different areas, including in lighting and optical sensors applications, such as pressure sensors and biosensors. Following the demand for outstanding luminescent materials, there is also a request for fast, economic and an easy scale-up process for their production. Regarding these demands, laser floating zone, solution combustion synthesis and pulsed laser ablation in liquid techniques are explored in this thesis for the production of single crystals, nanopowders and nanoparticles of lanthanides doped zirconia based hosts. Simultaneously, a detailed study of the morphological, structural and optical properties of the produced materials is made. The luminescent characteristics of zirconia and yttria stabilized zirconia (YSZ) doped with different lanthanide ions (Ce3+ (4f1), Pr3+ (4f2), Sm3+ (4f5), Eu3+ (4f6), Tb3+ (4f8), Dy3+ (4f9), Er3+ (4f11), Tm3+ (4f12), Yb3+ (4f13)) and co-doped with Er3+,Yb3+ and Tm3+,Yb3+ are analysed. Besides the Stokes luminescence, the anti- Stokes emission upon infrared excitation (upconversion and black body radiation) is also analysed and discussed. The comparison of the luminescence characteristics in materials with different dimensions allowed to analyse the effect of size in the luminescent properties of the dopant lanthanide ions. The potentialities of application of the produced luminescent materials in solid state light, biosensors and pressure sensors are explored taking into account their studied characteristics.
O progresso observado nas últimas décadas na área da fotónica e optoelectrónica, acompanhado de um desenvolvimento exponencial nas áreas da nanociência e nanotecnologia, resulta numa constante procura por materiais luminescentes eficientes com características cada vez mais exigentes. Matrizes de largo hiato energético dopadas com iões lantanídeos assumem-se, atualmente, como uma classe de materiais luminescentes de elevada importância tecnológica. Dentro destas, a zircónia apresenta uma combinação de propriedades químicas e físicas que a potenciam como matriz para a incorporação dos iões mencionados, tendo em vista o seu uso em diversas áreas, destacando-se as aplicações em iluminação e sensores óticos, entre os quais sensores de pressão e biossensores. Associada à necessidade de materiais luminescentes com características superiores, encontra-se a necessidade de técnicas de produção rápidas, económicas e com potencial para produção em larga escala. Tendo em conta estas necessidades, técnicas como a fusão de zona com laser, combustão em solução e ablação laser em meio líquido são exploradas neste trabalho para a produção de monocristais, nanopós e nanopartículas de matrizes à base de zircónia intencionalmente dopadas com lantanídeos. Em simultâneo, é realizado um estudo detalhado das propriedades morfológicas, estruturais e óticas dos materiais produzidos. São estudadas as características luminescentes de matrizes de zircónia (ZrO2) e zircónia estabilizada com ítrio (YSZ) dopadas com vários iões lantanídeos (Ce3+ (4f1), Pr3+ (4f2), Sm3+ (4f5), Eu3+ (4f6), Tb3+ (4f8), Dy3+ (4f9), Er3+ (4f11), Tm3+ (4f12), Yb3+ (4f13)) e co-dopadas com Er3+,Yb3+ e Tm3+,Yb3+. Para além da luminescência de Stokes, foi avaliada e discutida a emissão anti-Stokes (upconversion e radiação de corpo negro) sob excitação no infravermelho. A comparação da luminescência em materiais com diferentes dimensões permitiu analisar o efeito do tamanho nas propriedades luminescentes dos iões dopantes. A discussão do trabalho é acompanhada por uma integração dos resultados visando as aplicações destes materiais luminescentes em emissores do estado sólido, biossensores e sensores de pressão.
Araujo, Micheline dos Reis. "Obten??o e caracteriza??o de di?xido de estanho nanoestruturado pelo m?todo de s?ntese cont?nua por combust?o em solu??o". Universidade Federal do Rio Grande do Norte, 2012. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12745.
Texto completoCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Continuous Synthesis by Solution Combustion was employed in this work aiming to obtain tin dioxide nanostructured. Basically, a precursor solution is prepared and then be atomized and sprayed into the flame, where its combustion occurs, leading to the formation of particles. This is a recent technique that shows an enormous potential in oxides deposition, mainly by the low cost of equipment and precursors employed. The tin dioxide (SnO2) nanostructured has been widely used in various applications, especially as gas sensors and varistors. In the case of sensors based on semiconducting ceramics, where surface reactions are responsible for the detection of gases, the importance of surface area and particle size is even greater. The preference for a nanostructured material is based on its significant increase in surface area compared to conventional microcrystalline powders and small particle size, which may benefit certain properties such as high electrical conductivity, high thermal stability, mechanical and chemical. In this work, were employed as precursor solution tin chloride dehydrate diluted in anhydrous ethyl alcohol. Were utilized molar ratio chloride/solvent of 0,75 with the purpose of investigate its influence in the microstructure of produced powder. The solution precursor flux was 3 mL/min. Analysis with X-ray diffraction appointed that a solution precursor with molar ratio chloride/solvent of 0,75 leads to crystalline powder with single phase and all peaks are attributed to phase SnO2. Parameters as distance from the flame with atomizer distance from the capture system with the pilot, molar ratio and solution flux doesn t affect the presence of tin dioxide in the produced powder. In the characterization of the obtained powder techniques were used as thermogravimetric (TGA) and thermodiferential analysis (DTA), particle size by laser diffraction (GDL), crystallographic analysis by X-ray diffraction (XRD), morphology by scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and electrical conductivity analysis. The techniques used revealed that the SnO2 exhibits behavior of a semiconductor material, and a potentially promising material for application as varistor and sensor systems for gas
A S?ntese Cont?nua por Combust?o em Solu??o (SCCS) foi empregada na obten??o de p?s de di?xido de estanho nanoestruturados. Basicamente, uma solu??o precursora ? preparada, sendo posteriormente atomizada e aspergida na chama, onde ocorre a combust?o, levando ? forma??o das part?culas. A t?cnica apresenta um grande potencial na produ??o de nanopart?culas, principalmente pelo baixo custo de insumos e equipamentos. O di?xido de estanho (SnO2) nanoestruturado tem sido amplamente utilizado em diversas aplica??es, principalmente como sensores de g?s e varistores. No caso dos sensores ? base de cer?micas semicondutoras, em que as rea??es de superf?cies s?o respons?veis pela detec??o dos gases, a import?ncia da ?rea superficial e do tamanho de part?culas ? ainda maior. A prefer?ncia por um material nanoestruturado deve-se ao fato de que essas entidades apresentam alguns pontos fundamentais tais como, o aumento significativo da ?rea superficial comparados aos p?s microcristalinos convencionais e o reduzido tamanho de part?cula, que pode beneficiar certas propriedades como alta condutividade el?trica, alta estabilidade t?rmica, mec?nica e qu?mica. Neste trabalho, foram empregados como solu??o precursora cloreto de estanho dihidratado dilu?dos em ?lcool et?lico anidro. Foi utilizada a raz?o molar cloreto/solvente de 0,75 no intuito de investigar sua influ?ncia na microestrutura do material obtido. O fluxo da solu??o precursora foi de 3 mL/min. A an?lise por difra??o de raios X da solu??o precursora com raz?o molar cloreto/solvente de 0,75 indicou a obten??o de um p? cristalino e monof?sico e todos os picos s?o atribu?dos a fase SnO2. Par?metros de s?ntese como dist?ncia da chama com o atomizador, dist?ncia do sistema de capta??o com a chama piloto, raz?o molar e fluxo da solu??o precursora n?o afetaram a fase di?xido de estanho no material obtido. Na caracteriza??o do p? obtido, foram utilizadas t?cnicas como an?lises termogravim?tricas (ATG) e termodiferenciais (ATD), granulometria por difra??o de laser (GDL), an?lise cristalogr?fica por difra??o de raios X (DRX), morfologia por microscopia eletr?nica de varredura (MEV), microscopia eletr?nica de transmiss?o (MET), medida de ?rea superficial espec?fica (BET) e ensaio de condutividade el?trica. O conjunto de t?cnicas revelaram que o SnO2 apresenta comportamento de um material semicondutor, sendo um material potencialmente promissor ? aplica??o como varistor e em sistemas de sensores ? gases
Cho, Yung-Da y 卓永達. "Nanocrystalline LiMn2O4 Derived by HMTA-Assisted Solution Combustion Synthesi". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/59968018874729829648.
Texto completo國立中央大學
化學工程與材料工程研究所
92
This dissertation covers the synthesis and lithium-intercalating properties of LiMn2O4 prepared by a combustion process with ammonium nitrate as a porogenic agent and Hexamethylenetetraamine (HMTA) as a fuel. The synthesis parameters, temperature and duration of calcination and lithium stoichiometry, as well as metal ion:fuel mole ratio, were optimized in order to obtain products with the best electrochemical activity. The phase transitions of the products were investigated by thermogravimetric and differential thermal analyses, Structural properties of the products were investigated by X-ray diffraction, surface morphology by scanning electron microscopy and transmission electron microscopy, and surface area by the BET method. Lithium intercalation properties were studied by galvanostatic charge-discharge studies for different rate windows. The various redox regions and phase changes occurring during the charge-discharge processes were studied by cyclic voltammetry. The precursors for the synthesis of LiMn2O4 were metal nitrates dissolved in an aqueous solution of ammonium nitrate and HMTA in various mole ratios of total metal ion to fuel and the products were obtained by calcination at different temperatures and times. The optimal synthesis conditions were found to be 10h calcination at 700°C with lithium stoichiometry and mole ratio of total metal ion to fuel at 1.00. At a 0.1 C rate between 3.0 and 4.3 V, the product gave a first-cycle discharge capacity of 113 mAh/g, which faded to 88 mAh/g in the 200th cycle, with charge retention of 80%. The weight loss that occurs in the range from room temperature to about 120°C is ascribed to superficial water loss, as well as water loss from the hydration of manganese nitrate tetrahydrate, which begins to decompose at temperatures above 100°C. The sharp endotherm at 255°C is due to the melting of LiNO3. The main decomposition and product formation begin around 300°C. All the diffractograms show patterns corresponding to the cubic spinel structure in the Fd3m space group, suggesting that LiMn2O4 was formed during the initial decomposition of the mixture at 500°C itself. The particles were crystalline and had an average particle size of 10 ~ 40 nm, and a BET surface area of about 3.0361 m2/g. The good electrochemical behavior of the product was attributed to the nanocrystalline LiMn2O4 cathode particles by a modified solution combustion process.
You-HaoChang y 張祐豪. "Solution combustion synthesis of CaFe2O4 powder photocatalysts for CO2 photoconversion". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/24s847.
Texto completoChen, Chia-Ming y 陳嘉民. "Preparation of phosphor powders using microwave assisted solution combustion synthesis method". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/30680373239936951856.
Texto completo國立成功大學
化學工程學系碩博士班
94
Microwave heating technique is a high efficient heating way, and there are many advantages such as capable of achieving high temperature, rapid, and uniform heating, therefore, it has been used widely recently. In this thesis, the microwave-assisted the solution combustion method was used to prepare Zn2SiO4:Mn, Y2O3:Eu, Y3Al5O11:Ce, BaMgAl10O17:Eu phosphors which can emit different colors, respectively. The experimental parameters such as active ion concentration, firing temperature, the origin of reactant, fuel, firing atmosphere, the type of firing, will be discussed to find the essential factor and to research better phosphor and high efficient phosphors could be obtained. For Zn2SiO4:Mn, the results show that the highest luminescent intensity could be achieved after calcining at 1200℃(under nitrogen atmosphere) with 3 mol% Mn doped. For YAG, the highest luminescent intensity was at 1600℃ with 3.5% Ce doped. For Y2O3, the highest luminescent intensity was at 1200℃ with 15% Eu doped. As shown in XRD patterns, a high purity of BAM structure could be obtained when calcined at 1400℃and the crystalline increases with increasing temperature and reaches its maximum at 1650℃ under reducing atmosphere (5% H2 + 95% N2) with 6% Eu doped.
Ou, Yun Pin y 歐允斌. "A Study on Solution Combustion Synthesis of Aluminum Nitride Coated Carbon". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/74175511954491861195.
Texto completo國立成功大學
電機工程學系
102
Great electric insulation, high thermal conductivity, low dielectric constant, and low thermal expansion coefficient make AlN a very promising material for electric applications. Due to the high cost of the material, it is hard to be popular. In the study, we sintered the precursor-coated AlN powder at 800°C、900°C and 1000°C by SHS in order to obtain carbon-coated AlN powder for lower-cost synthesis use and further applications. We add sucrose in the 70% nitric acid solution first, wait until it was fully dissolved, then add AlN powder in the solution. After two steps of drying, it was sintered under Ar atmosphere for 2 hours. At last, we studied the density, grain, microstructure, dielectric properties and thermal conductivity with the product. We found that although the density and shrinkage rate increase as the sintered temperature increases, but it was not apparent. The X-ray patterns showed as we add more carbon precursor, the more carbon atom will substitute the “N” atom in the AlN crystal structure during the whole combustion process which will result in peak shift. The SEM also showed pores and defects from breaking plane of the product. For dielectric properties, we found as we increased the carbon precursor concentration, the dielectric properties didn’t get improved. We obtained the best dielectric constant 13.17 and dielectric loss 0.314 with 25wt% precursor concentration sintered at 800°C. At last, we obtained the thermal conductivity 1.048 W/m•K from the sample synthesized at 800°C. with 35wt% precursor added.
Sheng-ChunTseng y 曾聖淳. "Combustion Synthesis of AlN-SiC Solid Solutions and their Applications". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/k65wth.
Texto completo國立成功大學
化學工程學系碩博士班
101
Aluminum nitride (AlN) has many superior properties, but in practical application has not been growth rapidly as expected, one of the main reasons is the application problems has not resolved. The key point of the application problems is that AlN is easy to react with water for hydrolysis and deliquescence. The lattice structure, density and atomic size of AlN and silicon carbide (SiC) are very similar that they can form solid solutions in under certain conditions. This thesis wants to improve the hydrolyzed resistance and moisture resistance of AlN by solid solutions of AlN-SiC. Combustion synthesis AlN-SiC solid solutions at low nitrogen pressure region: properties decide by the ratio of Al and Si, the nitrogen pressure has poor correlation with properties. The flaky aluminum is unsuitable to synthesis solid solutions Due to the physical factors of shape. The experiment results show that AlN-SiC solid solutions synthesis by combustion synthesis has better hydrolyzed resistance and moisture resistance, reduce the forming rate of aluminium hydroxide (Al(OH)3) obviously. At high temperature (110℃) surrounding, the hydrolyzed resistance of AlN-SiC solid solutions even better than the phosphoric acid (H3PO4) surface treatment of AlN. The composition of AlN increase, the property of AlN-SiC solid solutions trend to AlN, but only solid solution trace amounts of SiC (5 mol%) can extend the time of forming Al(OH)3 obviously. Although combustion synthesis of AlN-SiC solid solutions has unreacted agent, the composites with epoxy has high thermal conductivity above half of AlN’s composites.
Chen, Jun-Hong y 陳俊宏. "Formation of Solid Solutions of Ternary Carbides by Combustion Synthesis". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/56395174259057886856.
Texto completo逢甲大學
航太與系統工程所
99
Formation of the solid solutions of ternary carbides (Ti,Nb)2AlC, (Cr,V)2AlC, and Ti3(Al,Si)C2, was conducted by self-propagating high-temperature synthesis (SHS). For the preparation of (Ti,Nb)2AlC, three reactant mixtures composed of Ti-Nb-Al-C, Ti-Nb2O5-Al-C, and Ti-Nb2O5-Al-Al4C3 were adopted. The solid solution of (Cr,V)2AlC was synthesized from the powder compacts of Cr2O3-V2O5-Al-C and Cr2O3-V2O5-Al-C-VC. The TiC-, SiC-, and Al4C3-added samples were used to produce Ti3(Al,Si)C2. The effect of sample stoichiometry was studied on the product composition and morphology, combustion wave velocity, and reaction temperature. The combustion process proceeded with a self-sustaining reaction front. For the reactant compacts of Ti-Nb-Al-C and Ti-Nb2O5-Al-C, the increase of Ti content in (Ti,Nb)2AlC increased the combustion velocity. Although the reversed trend was observed for the samples composed of Ti-Nb2O5-Al-Al4C3, the combustion velocity and temperature of the Ti-Nb2O5-Al-Al4C3 sample were higher than those of the Ti-Nb-Al-C and Ti-Nb2O5-Al-C powder compacts. The reaction front velocity was almost independent of the initial composition of the Cr2O3-V2O5-Al-C samples. With the addition of VC, the combustion velocity decreased with Cr content in the product (Cr,V)2AlC. On account of the variation of reaction exothermicity with sample stoichiometry, it was found that with an increase in the Al content of as-synthesized Ti3(Al,Si)C2 the combustion temperature and reaction front velocity decreased moderately for the TiC-added sample but substantially for the sample adopting Al4C3. However, a significant increase in both combustion wave temperature and velocity was observed for the SiC-added sample. The XRD analysis indicates that in addition to the dominant phase (Ti,Nb)2AlC, there are secondary phases TiC, NbC, NbAl3, and Nb2Al. The optimal product was obtained from the Ti-Nb-Al-C sample. For the formation of (Cr,V)2AlC, the binary carbide Cr7C3 was detected as the minor phase and the optimal composition of the product was obtained from the sample without addition of VC. On the synthesis of Ti3(Al,Si)C2, the final products contain TiC as a second phase and some other minor species like SiC and Ti3Al. For the Al4C3-added samples, however, the resulting products are dominated by TiC. According to the experimental evidence, the TiC-containing sample is the most favorable for the preparation of Ti3(Si,Al)C2 through the SHS process.
Moreira, Marco António Mesquita. "Composition ratio effect in IGZO using solution combustion synthesis for TFT applications". Master's thesis, 2017. http://hdl.handle.net/10362/53148.
Texto completoYang, Wen-jung y 楊文榮. "Combustion Synthesis of Solid Solutions of M-site MAX Ternary Carbides". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/39328101808894726467.
Texto completo逢甲大學
航太與系統工程學系
101
Formation of (Ti,V)2AlC, (Cr,V)2AlC and (Ti,Cr)2AlC ternary solid solutions was conducted by self-propagating high-temperature synthesis (SHS). Effects of starting materials and sample stoichiometries were studied on the combustion temperature, flame-front velocity, and product composition and microstructure. In this study, TiO2 or Ti, Cr2O3 or Cr, and V2O5 were adopted as the sources of Ti, Cr, and V. Carbon was supplied by using Al4C3, TiC and carbon black powders. For the synthesis of (Ti,V)2AlC, experimental results indicated that with an increase of the Ti content, the combustion propagation changed from a planar to spinning mode and the extent of the sample melting was reduced. Flame-front velocity increased with increasing V2O5 content, but no obvious change in combustion velocity was found for the samples containing TiC. The synthesized products were composed mainly of (Ti,V)2AlC and Al2O3, and were characterized by a laminated microstructure. The fraction of Ti at the solution site was ranged from 0.1 to 0.6 for the samples using TiO2 and V2O5, and the Ti proportion was extended to 0.9 for the samples adopting Ti in place of TiO2. The combustion propagation phenomena associated with formation of (Cr,V)2AlC were similar to those of (Ti,V)2AlC. Due to substantial melting of the samples, the composition dependence of the flame velocity was not very apparent. For the samples containing Cr and V2O5, the flame velocity decreased as the content of V2O5 was reduced. The fraction of Cr at the solution site ranged 0.25~0.9 and 0.25~0.6 for the powder compacts adopting Cr2O3-V2O5 and Cr-V2O5, respectively. For the formation of (Ti,Cr)2AlC, the SHS processes exhibited different types of the combustion propagation including the planar front, pulsating motion, and spiral wave with multiple hot spots. The shape of the sample remained almost unchanged after combustion. Among samples of different starting materials, the samples with TiO2 and Cr2O3 had the highest flame velocity. The combustion velocities of the samples with Ti and Cr2O3 were relatively consistent. The use of carbon black accelerated the combustion wave. Instead of forming (Ti,Cr)2AlC, the solid sate combustion yielded Cr2AlC, TiC, and Al2O3.
江長鴻. "Studies of Combustion Synthesis on Ternary Solid Solutions in Different Substitution Sites". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/16641041368878949235.
Texto completo逢甲大學
航太與系統工程學系
102
In this research, Self-Propagating High-Temperature Synthesis (SHS) was applied to synthesize MAX ternary solid solutions. The target products to be studied included Ti2Al(C,N), Ti2(Al,Sn)C, Ti3(Al,Sn)C2, and (Ti,Ta)2AlC. Effects of the sample stoichiometry on the flame-front velocity, combustion temperature, phase composition and microstructure of the product were investigated. The first part of this study focused on the X-site solid solution, Ti2Al(C,N). Nitride compounds, TiN, AlN, BN, and Si3N4, were adopted as the solid sources of nitrogen to mix with Ti, Al, and C powders for the production of Ti2Al(C,N). Experimental results showed that combustion velocity and temperature decreased with increasing TiN and AlN. When BN and Si3N4 were used, a broad range of the N substitution from Ti2Al(C0.8N0.2) to Ti2Al(C0.2N0.8) was achieved. Due to reduced reaction exothermicity, the degree of element substitution was restricted between Ti2Al(C0.8N0.2) and Ti2Al(C0.5N0.5) for the TiN- and AlN-added samples. The second part was to study the A-site solid solutions, Ti2(Al,Sn)C and Ti3(Al,Sn)C2, from the powder mixtures of Ti, Al, Sn, and carbon black powders with addition of TiC or Al4C3 as the other source of carbon. A better degree of the product formation was obtained for Ti2(Al,Sn)C than Ti3(Al,Sn)C2. In particular, the samples adopting TiC were more favorable than those with Al4C3 for the synthesis of Ti2(Al,Sn)C. The third part of this study was to fabricate the M-site solid solution, (Ti,Ta)2AlC, from elemental powder compacts of Ti, Ta, Al, and carbon black. With an increase in the Ta content, the flame-front velocity was reduced but reaction temperature was slightly changed. Formation of (Ti,Ta)2AlC was confirmed by the XRD pattern of the product. Based upon the SEM observations, the plate-like microstructure typical of the MAX ternary compound was found. In addition, two MAX solid solutions featuring double substitution locations were studied and they were the MX- and AX-site carbonitrides, (Ti,Nb)2Al(C,N) and Ti2(Al,Sn)(C,N). Finally, this research examined the relationship between formation of MAX solid solutions and the radius of substitution atoms. It was found that two atoms at substitution sites with a radius difference less than 10% facilitated the formation of MAX solid solutions by SHS.
Moreira, Pedro Gabriel. "Inkjet printing of ZTO and AlOx solution combustion inks for electronic devices production". Master's thesis, 2022. http://hdl.handle.net/10362/132738.
Texto completoÓxidos metálicos amorfos processados por solução apresentam desempenho eletrónico competitivo para aplicações que requerem transparência e flexibilidade. Estes óxidos são compatíveis com variadas técnicas de impressão mas a otimização destes processos é crucial para se obter dispositivos estáveis, reprodutiveis e de alto desempenho. É também importante encontrar alternativas a elementos usados frequentemente como o gálio e indio mas que são raros e/ou apresentam toxicidade, bem como descobrir solventes alternativos mais seguros do que os que são habituais nesta indústria. A compatibilidade com inkjet printing (IJP) de óxido de alumínio (AlOx) (2-methoxyethanol como solvente) e óxido de estanho e zinco (ZTO) usando vários solventes: etanol, etanol (50%).H2O (50%), 1-methoxy-2-propanol (1-MP) e 2-methoxyethanol (2-ME) foi testada. ZTO baseado em etanol depositado por spin-coating não mostrou resultados promissores para aplicação em dispositivos e embora transistores baseados em 1-MP como solvente tenham obtido bons resultados por spin-coating, IOn/IOff ratios de 105 e baixo subthreshold swing de 0.66V.dec-1, a tinta nao mostrou qualquer indicação de ser compatível com inkjet. IJP de ZTO e AlOx baseados em 2-ME como solvente foi otimizado com variação do tempo de tratamentos UV, drops-per-inch (DPI), tratamentos de post annealing, velocidade de impressão e número de camadas. IJP de condensadores MIS (metal-isolante-semicondutor) com AlOx com 2-ME como solvente foram produzidos com uma e duas camadas demonstrando tensões de breakdown suiperiores a 1MV.cm-1. Por último TFTs de ZTO/AlOx produzidos por IJP e baseados em 2-ME como solvente exibiram desempenho copetitivo com mobilidades de 2.2 cm2.V-1.s-1, SS de 0.49 V.dec-1 e currente IOn/IOff de 103 nos melhores dispositivos. Estes são os primeiros TFTs produzidos totalmente por IJP no CENIMAT/CEMOP exibindo valores competitivos com os reportados na literatura para TFTs de ZTO/AlOx de spin-coating processados por solução.
Trigo, Pedro Gil Dias. "Oxide transistors produced by Combustion Synthesis: Influence of the PVP on the properties of the insulator". Master's thesis, 2017. http://hdl.handle.net/10362/42277.
Texto completo(6997700), Wooram Kang. "HYDROGEN GENERATION FROM HYDROUS HYDRAZINE DECOMPOSITION OVER SOLUTION COMBUSTION SYNTHESIZED NICKEL-BASED CATALYSTS". Thesis, 2019.
Buscar texto completoLin, Yen-Ting y 林彥廷. "Synthesis of Novel Cathode Materials Ba0.5Sr0.5CuxFe1-xO3-δ for IT-SOFC by Solution Combustion Methode". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/2h343k.
Texto completo國立臺北科技大學
資源工程研究所
97
BaySr1-yCoxFe1-xO3-δ is considered to be one of the best cathode materials for IT-SOFC. The material, however, has also been found to carry with it several disadvantages, notably high thermal expansion coefficient, low conductivity, and high cost. The study accordingly uses copper to replace cobalt to develop a new cathode material Ba0.5Sr0.5CuxFe1-xO3-δ for IT-SOFC. The objective of the study is two-fold: 1.Synthesis of pure Ba0.5Sr0.5CuxFe1-xO3-δ perovskite; and 2. Discussion of the material’s chemical and physical properties. Ba0.5Sr0.5CuxFe1-xO3-δ perovskite was synthesized by solution combustion. As indicated by the results, glycine-nitrate-process (GNP) was able to shorten the time of synthesis and reduce the calcination temperature. Pure cubic perovskite products were observed in X-ray diffraction (XRD) measurement with Cu-dopping at X = 0.1 to 0.3. And the composition of the products was confirmed using ICP-AES. It was also observed that, as the G/M ratio rose, three different combustion modes occurred respectively: volumetric combustion, self-propagating combustion, and smothering combustion. The situation at G/M=2 and pH=2 was identified to be the best condition for synthesizing Ba0.5Sr0.5CuxFe1-xO3-δ. Moreover, the study also adopted EDTA-glycine combustion method to prepare Ba0.5Sr0.5CuxFe1-xO3-δ - BaCeO3 perovskite. This method boasts an extensive synthesis range, so Ba0.5Sr0.5CuxFe1-xO3-δ - BaCeO3 could be synthesized at pH from 4 to 11. Moreover, adding NH3NO2 was found to be good for combustion reaction. In this study, chemical stability with electrolyte, conductivity, and sintering behavior were examined. Cu-doping appeared to decrease the melting point of the synthesized material. Of the three common electrolytes (GDC, SDC, and YSZ), GDC was found to work best with Ba0.5Sr0.5CuxFe1-xO3-δ in achieving high chemical stability. The best conductivity of 127.46 S/cm was achieved when the temperature was 346℃ and X=0.2. Copper would diffuse to the surface when the sintering temperature rose above the melting point of the synthesized material. The study finds Ba0.5Sr0.5CuxFe1-xO3-δ compounds capable of sustaining high conductivity at low temperature. Its ability to reduce synthesis temperature and material cost makes Ba0.5Sr0.5CuxFe1-xO3-δ a promising new cathode material for IT-SOFC.
Sherikar, Baburao Neelkantappa. "Investigations of Solution Combustion Process and their Utilization for Bioceramic Applications". Thesis, 2014. http://hdl.handle.net/2005/3015.
Texto completoChing-MeiWang y 王卿昧. "Solution combustion synthesis of TiO2 nanoparticles and their applications in photocatalyst and dye-sensitized solar cell". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/35624683033864536459.
Texto completo國立成功大學
化學工程學系碩博士班
101
Titanium dioxide (TiO2) has demonstrated several potential applications, including photocatalysts, dye-sensitized solar cell (DSSC), pigment, and electronic data storage memory, etc. In this thesis, TiO2 powders were synthesized by a solution combustion synthesis method in which glycine, urea and thiourea were used as the fuel and titanyl nitrate was used as the oxidizer. Various fuel-to-oxidizer ratios were studied for their effects on the combustion phenomena and the properties of the synthesized TiO2. The fuel-to-oxidizer ratio was found to determine the maximum combustion temperature, which in turn affects the specific surface area, crystallite size, and weight fraction of anatase phase of the synthesized TiO2. The synthesized TiO2 all contain carbonaceous species and are either pure anatase or anatase–rutile mixed phase in crystalline structure. The photocatalytic activity of the TiO2 was found to correlate to a certain degree with the specific surface area, crystallitesize, weight fraction of anatase phase, and visible and IR absorbances. The mixed phase TiO2 shows a higher photocatalytic activity than the pure anatase phase TiO2 when containing a small fraction (<~25 wt%) of rutile phase but a lower phoyocatalytic activity when containing a large fraction (>~25 wt%) of rutile phase. The synthesized TiO2 all show higher photocatalytic activity than Degussa P25 TiO2. The enhanced photocatalytic activity was attributed mainly to sensitization by the carbonaceous species and larger amounts of hydroxyl group adsorbed on the TiO2 surface. These TiO2 nano powders were used to fabricate photoelectrodes for the DSSC and their performance was compared to that of the DSSC fabricated with Degussa P25 TiO2. The results showed that the TiO2 could work well as photoelectrode for DSSC. The solution combustion synthesis TiO2 contained impurities of C and/or S, thus exhibiting visible light absorption and reduced band gap. The open circuit voltage and the fill factor both varied little among the various TiO2 and thus both had little effect on the photoelectrical conversion efficiency (η). However, the variation of η was seen to be in quite a good agreement with that of the short circuit current (Isc), suggesting that η was dominated by Isc. Isc was found to be enhanced by light scattering effect due to the presence of large particles but reduced by high impurity content due to an increase in electron transfer resistance. In addition, the specific surface area of the powders was found to be an important factor affecting the Isc and thus the η.
Hu, Jyun-Ye y 胡俊業. "Synthesis and Luminescent Properties of Europium-ion doped MAl2O4(M : Ca, Sr, Ba) Phosphors by Solution Combustion Method". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/yx5dtn.
Texto completo國立臺北科技大學
材料科學與工程研究所
99
This study aimed to prepare MAl2O4(M = Ca, Sr, Ba)by solution combustion method. The impact of the doping concentration of Eu on the luminescence and lattice structure was examined. The 4f65d1 → 4f7 spectrum of Eu2+ fired in reduced atmosphere was continuous and broad. Depending on host lattices, various colors, intensity and characteristic of emission spectrum were recognized. Analyzing instruments like X-ray diffractometer (XRD), fluorescence spectrometer, and scanning electron microscope (SEM) were utilized to analyze the crystallinity, the phosphorescence characteristic, and the surface structure, respectively. Furthermore, with help of differential thermal (DTA) / thermogravimetry analyzer (TGA), conditions for firing process were explained. It was experimentally confirmed the reaction time could be effectively reduced by adopting solution combustion method. The product showed high purity and homogeneous distribution of particle size. As the Glycine/Metal nitrate(G/M) ratio increased, three different combustion modes - volumetric, self-propagating, and smothering combustion - occurred respectively. An appropriate G/M ratio resulted in SHS phenomenon, so that it was identified as the optimized synthesis condition. MAl2O4:Eu2+(M = Ca, Sr, Ba) phosphors showed a 6P7/2→ 8S7/2 transition with bluish 450 nm, greenish 520 nm and 500 nm emission. This phenomenon resulted from the covalence and crystal field splitting effects of the host lattice. In contrast, the emission peaks of MAl2O4:Eu3+(M = Ca, Sr) phosphors were originated from 5D0→ 7FJ(J=1,2,3,4) transition, which showed an orange-red color. Variation of host lattices did not play a critical role in this process. According to excitation spectra, the main excitation peaks of MAl2O4:Eu2+(M = Ca, Sr, Ba) and MAl2O4:Eu3+(M = Ca, Sr) phosphors are located at ultraviolet region. Stimulated by UV-LED, both of them could absorb the UV wave band red, green, and the blue three kind of phosphor way blending with white light. The white light generated by such conversion covered a wavelength range closer to that of the natural light. Owing to higher color rendering property, higher light color uniformity, and absence of color deviation, these phosphors have high application potential for the white light LED industry.
Chen, Yan-Wei y 陳彥瑋. "Process Development for Carbothermal Reduction and Nitridation Synthesis of alpha-SiAlON Phosphors by Using Solution Combustion Synthesized Precursors". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/71315113766484607359.
Texto completo國立成功大學
化學工程學系碩博士班
97
A commercial and potential method to synthesis nitrides or oxynitrides currently is reducing oxides at nitrogen atmosphere. Our laboratory has already successfully product silicon nitride and aluminum nitride from silicon oxide and aluminum oxide. This study used previous technical basis that our laboratory established to synthesis an advanced oxynitride material, SiAlONs which include silicon, aluminum, oxygen and nitrogen atom in its structure. Solution combustion synthesis we used that could help nitridation reaction precursors mix very well and close to nano-scale particle size. We could obtain α-SiAlON which was mainly phase in the product after precursors underwent carbothermal reduction nitridation and doped activator made the host have luminescent property. The study mainly focused on 1. carbon ratio, 2. reaction temperature, 3. seeds effects, 4. activator concentrations, 5. the effects of morphology of the precursors. The analytic instruments included XRD, PL, SEM and the best result achieved in this study when carbon was 4 times theoretical value, reaction temperature was 1500℃, Eu2+ was doped 0.5 and seed was doped 50 mol﹪.According to the SEM, we observed particle size distribution was from submicron to micron.
Martins, Raquel Azevedo. "Solution-based Metal Oxide Semiconductor Memristor". Master's thesis, 2021. http://hdl.handle.net/10362/129164.
Texto completoMemristores baseados em processos de solução têm demonstrado um grande potencial para cumprir requisitos da Internet das Coisas (IoT), como dispositivos de elevada densidade e ultrabaixo consumo de energia aliado a métodos de fabrico simples e de baixo custo. Neste trabalho, filmes finos de óxido de índio-gálio-zinco (IGZO) são produzidos através do processo de síntese por combustão. Para melhorar o desempenho dos filmes de IGZO em memristores, são estudados diferentes parâmetros: a variação da proporção molar, o número de camadas depositadas e a temperatura de recozimento. Os memristores com maior número de camadas recozidas à temperatura mais elevada apresentam baixa tensão de operação, boa resistência, ótimo rendimento e retenção de até 105 s à temperatura ambiente. A melhor condição alcançada foi um memristor IGZO (1:3:1) com 7 camadas depositadas recozidas a 300 ºC. Estes dispositivos podem ser programados num em modo de operação multinível até 8 estados resistivos diferentes. Além disso, os mesmos dispositivos apresentam características promissoras para aplicações de computação neuromórfica, uma vez que conseguem emular a plasticidade de uma junção sináptica, ao replicar a potenciação e depressão de uma sinapse. Os resultados alcançados são bastante promissores e mesmo em alguns casos superam o atual estado da arte.
Berberich, Thais Sayuri. "Development and functionalization of magnetic nanomaterials for biomedicine applications". Master's thesis, 2018. http://hdl.handle.net/10198/22119.
Texto completoDuring the past decade, researchers have shown an increased interest in multifunctional nanomaterials. Magnetic Nanoparticles (MNP) have been one of the most attractive types of nanomaterials used in different fields, as in environmental protection and biomedical applications. These applications include drug delivery, magnetic resonance imaging, magnetic hyperthermia, among others. MNPs have been synthesized by various methods. Amongst the most common may be referred: thermal decomposition, microemulsion, coprecipitation, solution combustion and sonochemical synthesis. The main objective of this MSc thesis is the development of biocompatible MNPs with high potential for the controlled release of drugs. For this purpose, a magnetic core based on magnetite is developed by two different approaches of Solution Combustion Synthesis. In the first approach, the synthesis of MNPs is obtained by reduction of Fe (III) using citric acid, and the in second approach, the MNPs are synthesized using tangerine peel extract for the reduction of Fe (III). However, the material produced with the extract was not magnetic, and it was decided to not continue the methodology with it. Then, the magnetic core, produced with citric acid, is coated with a resin prepared from formaldehyde, resorcinol and TEOS, which is later carbonized by pyrolysis at 600 ºC. Subsequently, the silica generated from TEOS is removed by etching with NaOH in order to create a void inside the particle, which take the known yolk-shell shape. Finally, the materials are functionalized with nitric acid and subsequent pluronic F-127, for its biocompatibility and dispersibility. These materials are then assessed in the controlled release of two different drugs to test the potential of the developed magnetic nanostructures for drug delivery applications: Doxorubicin (DOX) and Omeprazole (OME). Drug Loading Capacity and Efficiency of 0.936 μg·μg -1 and 93.6% for DOX and 0.335 μg·μg-1 and 33.5% for OME are obtained at pH 7.4, respectively. Finally, the drug release is tested at the pH of the normal tissue (pH 7.4) and at the pH of the extracellular environment of the tumor (pH < 6.5), simulating different circumstances of the human body.
Durante a última década, os pesquisadores tem mostrado um interesse crescente em nanomateriais multifuncionais. As nanopartículas magnéticas (MNPs) tem surgido assim como um dos tipos de nanomateriais mais promissores para diversos fins, podendo ser utilizado, por exemplo, em proteção ambiental e em aplicações biomédicas. De entre estas aplicações podemos citar a libertação controlada de fármacos, a ressonância magnética, o tratamento hipertermia magnética, entre outros. As MNPs podem ser sintetizadas das mais diversas maneiras, entre as quais as mais comuns são: decomposição térmica, microemulsão, coprecipitação, síntese por combustão de solução e síntese sonoquimica. O principal objetivo desta tese é desenvolver MNPs biocompatíveis com grande potencial para a libertação controlada de fármacos. Para isso, será produzido um núcleo magnético, feito de magnetite, considerando duas abordagem de síntese de combustão de solução. Na primeira abordagem, as MNPs são produzidas reduzindo o Fe (III) com ácido cítrico. Na segunda abordagem, o agente responsável pela redução dos iões de Fe (III) é um extrato de tangerina, porém utilizando esse agente o material produzido não era magnético, e optou-se por não continuar a metodologia com ele. Em seguida, o núcleo magnético, produzido com o ácido cítrico, é revestido com uma resina preparada a partir de formaldeído, resorcinol e TEOS, que posteriormente é carbonizada por pirólise a 600 ºC. Após a carbonização, a sílica gerada a partir de TEOS é removida com NaOH, a fim de criar um vazio no interior do material, que assume a forma conhecida como casca de gema. Finalmente, os materiais são funcionalizados com ácido nítrico e subsequente plurônico F-127, para obter características de biocompatibilidade e dispersibilidade. Os materiais sintetizados são então avaliados na libertação controlada de dois fármacos, para testar o potencial das nanoestruturas magnéticas nessa aplicação biomédica: Doxorrubicina (DOX) e Omeprazol (OME). Obteve-se uma capacidade de carga dos fármacos e uma eficiência de 0,936 μg·μg-1 e 93,6% para DOX e 0,335 μg·μg -1 e 33,5% para OME, respetivamente, obtidas a pH 7,4. Finalmente, a libertação do fármaco é testada no pH do tecido normal (pH 7,4) e no pH do ambiente extracelular do tumor (pH < 6,5), simulando diferentes circunstâncias do corpo humano.
Also, I gratefully appreciate for the financial support of Project “RTChip4Theranostics - Real time Liver-on-a-chip platform with integrated micro(bio)sensors for preclinical validation of graphene-based magnetic nanocarriers towards cancer theranostics”, with the reference NORTE-01-0145-FEDER-029394, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); and CIMO - UIDB/00690/2020 - funded by Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020
Firmino, Rita Maria Gomes. "Solution Processing of Doped Indium Oxide for Applications as Transparent Conducting Oxides". Master's thesis, 2022. http://hdl.handle.net/10362/133010.
Texto completoO óxido de índio (In2O3) tem sido amplamente utilizado e investigado como óxido condutor transparente (TCO). No entanto, alguns dos dopantes mais promissores para este óxido foram pouco estudados e ainda menos explorados por processos de solução. Este trabalho foca no desenvolvimento de filmes finos dopados (Hf, Mo e Zr) In2O3 processados por solução e na avaliação de vários parâmetros de recozimento nas propriedades do TCO. Diferentes sínteses de processamento, razão molar de catiões metálicos e número de camadas depositadas foram estudadas, concluindo que a concentração de 0,2 M e a deposição de 8 camadas por spin coating usando síntese de solução por combustão (SCS) foram os parâmetros mais favoráveis. TCOs dopados otimizados foram obtidos para In2O3 dopado com 0,5 M% Hf quando produzido a 400 ˚C, mostrando alta transparência na região visível do espectro, uma resistividade em volume de 5,73 × 10-2 Ω.cm, mobilidade de 6,65 cm2 / Vs e uma concentração de portadores de 1,72 × 1019 cm-3 . Finalmente, filmes finos de In2O3 dopados com 0,5 M% de Hf foram recozidos em recozimento térmico rápido (RTA) por 10 min a 600 ˚C, obtendo resultados melhores do que os anteriores, atingindo uma resistividade em volume de 3,95 × 10-3 Ω.cm, mobilidade de 21 cm2 /Vs e concentração de portadores de 7,98 × 1019 cm-3.
Кошкина, А. А. y A. A. Koshkina. "Анодные материалы на основе оксидов железа для литий-ионных аккумуляторов : магистерская диссертация". Master's thesis, 2019. http://hdl.handle.net/10995/79358.
Texto completoМагистерская диссертация посвящена установлению оптимальных параметров получения композитов из оксида железа и углерода (FeOx/C) посредством физико-химического исследования полученных образцов для дальнейшего использования в качестве анодных материалов литий-ионных аккумуляторов (ЛИА). Данная работа носит междисциплинарный характер и была выполнена в лаборатории химии соединений редкоземельных элементов ИХТТ УрО РАН, а также с использованием оборудования УЦКП «Современные нанотехнологии» УрФУ им. Б. Н. Ельцина.
Bharathi, R. ""Developing Device Quality Vanadium Dioxide Thin Films for Infrared Applications"". Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2966.
Texto completo