Dissertations / Theses on the topic 'Nanoparticulates'
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Zhao, Hongxia. "Studies of thermal, mechanical and fracture behaviors of rigid nanoparticulates filled polymeric composites /." access full-text access abstract and table of contents, 2005. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ap-b19887589a.pdf.
Full text"Submitted to Department of Physics and Materials Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy" Includes bibliographical references.
Luechau, Frank. "Process considerations for the recovery of bio-nanoparticulates in polymer-salt aqueous two-phase systems." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289385.
Full textWen, William Y. "Development of New Characterisation Methods to Study the Photocatalysis Processes at Nanoparticulate TiO2 Film Electrodes." Thesis, Griffith University, 2011. http://hdl.handle.net/10072/366132.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
Huang, Shanshan. "Nanoparticulate nickel sulfide." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54754/.
Full textKeating, Siobhan. "Nanoparticulate delivery systems for 5-fluorouracil." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343028.
Full textGovender, Thirumala. "Enhancing drug incorporation into nanoparticulate systems." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299551.
Full textSmugowski, Hubert Jakub. "Magnetic nanoparticulate catalysts in flow processes." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548956.
Full textAbass, Sara Abdelazeem Hassan. "Electronic properties of printed nanoparticulate silicon." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10027.
Full textKramberger, Iris. "Organic/inorganic hybrid nanoparticulate resonant contrast agents." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:a1af88c4-493b-45b0-b98c-5de9e09bdae1.
Full textGonfa, Girma Goro. "Hall effect in printed Nanoparticulate Silicon Networks." Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/6529.
Full textBilton, Matthew William. "Nanoparticulate hydroxyapatite and calcium-based CO2 sorbents." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/3847/.
Full textMonteiro, Vitor Augusto de Rego. "Nanoparticulas de polifosfato de aluminio." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250300.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Sistemas coloidais de polifosfatos metálicos (M3+) são versáteis fontes de novos materiais. Nos últimos anos, nesse laboratório, foram obtidos sóis, géis, espumas e partículas ocas. Os polifosfatos de metais são obtidos pela precipitação em meio aquoso, formando sistemas bifásicos, dos quais os diferentes materiais são obtidos de acordo com as condições experimentais usadas na sua preparação e processamento. As suspensões aquosas de partículas amorfas de polifosfato de alumínio (PfAI) foram preparadas em diferentes composições (3 ?: P/AI ?: 0.4) a partir das soluções aquosas de sulfato de alumínio, polifosfato de sódio e hidróxido de amônio em uma larga faixa de concentrações. A mistura dos três reagentes foi agitada à temperatura ambiente formando uma polidispersão estável. Cada amostra foi centrifugada e a medida de diâmetro efetivo das partículas do sobrenadante revelou valores entre 120 e 200 nm. A análise dos histogramas segundo uma distribuição multimodal ajustada à função de autocorrelação revelou a presença de partículas da ordem de 1 O nm e outras ainda menores. Em excesso de polifosfato (P/AI :? 4.5), o número de partículas obtido é menor, ao passo que em excesso de alumínio o diâmetro efetivo das partículas aumentou. As micrografias eletrônicas de transmissão (MET) mostraram partículas pequenas isoladas e agregados de nanopartículas formados durante a secagem provavelmente por agregação das nanopartículas por adesão capilar. O diâmetro das partículas secas, observadas por MET, está na faixa de 2 a 16 nm. As características dos colóides de polifosfatos permitem traçar o seguinte modelo: a associação de íons polivalente hidratados em solução aquosa forma redes poliônicas com alto grau de hidratação. Essa nova fase é formada quando um tamanho crítico das redes é atingido em função de um número crítico de associações entre os íons. A tensão interfacial desse sistema é baixa porque ela depende fortemente da composição das fases. Baixos valores de tensão interfacial permitem a formação e estabilização de nanopartículas
Abstract: M3+ polyphosphates colloidal systems are versatile sources of new materiais. ln recent years we have demonstrated the formation of sois, gels, foams and hollow particles, by using these salts. They are formed by precipitation in aqueous media; this phase separation yields different products, depending on the actual conditions used. Particles of noncrystalline aluminum polyphosphate (AI PP) of many different compositions (3 ? P/AI ; ? 0.4) are prepared from aqueous solutions of aluminum sulphate, sodium polyphosphate and ammonium hydroxide within a broad concentration range. The admixture of dilute aqueous solutions of the parent reagents, under strong stirring and at a room temperatura yields stable aqueous dispersions of AIPP nanoparticles within 3 ; ? P/AI ;? 2 molar ratios. After centrifugation, the supernatants of these dispersions have an effective particle diameter ranging from 120 to 200 nm. However, the analysis of the autocorrelation function assuming a multimodal particle size distribution reveals the presence of a population of parti eles as small as 1 O nm. ln the presence of an excess of phosphate (P/AI ;? 4.5), the number of nanoparticles obtained is reduced while in the presence of an excess of aluminum the effective particle diameter is increased. The transmission electron micrographs of the particles show large regions with isolated nanoparticles and also aggregates, formed during sample drying probably by capillary adhesion and coalescence among particles. The diameters of isolated nanoparticles are in 2 - 16 nm range. Ali the features of the metal polyphosphates colloids are understood following this model: the strongly hydrated polyvalent ions associate in solution, forming polyionic network domains, with a high degree of hydration. The network domains separate as a new phase when a criticai size is reached, but the interfacial tension with the parent liquid is strongly dependent on the chemical composition. Very low interfacial tensions allow the formation of nanoparticles, depending on the extent of the networks and thus on the ionic concentration
Mestrado
Buthelezi, Motlalepula Isaac. "Synthesis and properties of nanoparticulate titanium dioxide compounds." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_9038_1298632656.
Full textAn electrolytic cell was designed and constructed for the preparation of TiO2 nanotubes. Conditions of anodic oxidation were established to reproducibly prepare TiO2 nanotubes of average length 35-50 &mu
m vertically orientated relative to the plain of a pure titanium metal sheet. A non-aqueous solution of ethylene glycol containing small percentage of ammonium fluoride was used as the electrolyte with an applied voltage of 60 V. The morphology and dimensions of the nanotube arrays were studied by scanning (SEM) and transmission (TEM) electron microscopy. The effect of calcination under different conditions of temperature and atmosphere (nitrogen, argon and air) were assessed by both X-ray diffraction (XRD) and cyclic voltammetry (CV). Cyclic voltammetry studies were made possible by construction of a specially designed titanium electrode upon which the nanotubes were prepared. CV studies established a positive correlation between crystallinity and conductivity of the nanotubes. Doping of the nanotubes with nitrogen and carbon was established by elemental analysis, X-ray photoelectron spectroscopy (XPS) and Rutherford back scattering (RBS). The effect of nonmetal doping on the band gap of the TiO2 nanotubes was investigated by diffuse reflectance spectroscopy (DRS).
Mergler, Bianca Isolde. "Enterocyte uptake of nanoparticulate iron(III) oxo-hydroxide." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610413.
Full textSalvage, Jonathan Peter. "A novel phosphorylcholine-based nanoparticulate drug delivery system." Thesis, University of Brighton, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499068.
Full textSolana, Oluwole David. "Production and characterisation of nanoparticulate silicon photovoltaic devices." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/9024.
Full textA first approach in fabricating electronically functional nanoparticulate silicon solar cells, by using low cost screen printing on paper substrates, has been developed. The semiconductor materials used consisted of n- and p-type silicon nanoparticles produced by means of high energy mechanical milling, as well as commercially sourced nanophase intrinsic silicon powder. Results from microscopy revealed that the nanoparticles had formed clusters that were capable of transporting charge through the device. Results from the electrical characterisation show that the printed devices exhibit electrical properties characteristic of silicon PV devices, confirming that the experimental process followed resulted in the successful production of a functional silicon solar cell. This thesis outlines the particle production process, ink formulation technique, and the device fabrication process. Results from the physical characterisation of the nanopowders and printed layers using optical and scanning electron microscopy, as well as an analysis of the electrical performance of the printed devices are also presented.
Foston, Marcus Bernard. "Cyclic, tethered and nanoparticulate silicones for material modification." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24762.
Full textCommittee Chair: Dr. Haskell W. Beckham; Committee Member: Dr. Anselm Griffin; Committee Member: Dr. Johannes Leisen; Committee Member: Dr. Sankar Nair; Committee Member: Dr. Uwe Bunz.
OLIVEIRA, Rodrigo José de. "Surfatantes fotorreativos para síntese de nanoparticulas." Universidade Federal de Pernambuco, 2012. https://repositorio.ufpe.br/handle/123456789/11857.
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CNPq CAPES RENAMI Merck-Southampton
Uma nova classe de surfatantes, chamados fotorreativos (PRS) é apresentada aqui. Estes são anfifilos que podem atuar como precursores em reações fotoquímicas para a síntese de nanopartículas metálicas e de óxidos. Nesta tese foram estudados os seguintes PRSs: 2- etilhexanoato de cobalto (II), Co(EH)2; 2-etilhexanoato de bismuto (III), Bi(EH)3; 2- etilhexanoato de ferro (III), Fe(EH)3 e o 2-etilhexanoato de Manganês (II), Mn(EH)2. As micelas invertidas destes PRSs foram estudadas por viscosidade e espalhamento de nêutrons a baixo ângulo, SANS. Foi verificado que, quando dispersos em hidrocarbonetos como o heptano, estes PRSs formam agregados pequenos com números de agregação entre 3 e 7. Da mesma forma, micelas invertidas mistas de PRS e aerosol-OT (AOT) foram estudadas por viscosimetria, condutividade e SANS. A adição do PRS no sistema misto em heptano não levou a consideráveis mudanças na estrutura micelar, mas em ciclohexano há um aumento na curvatura das micelas, fato atribuído à baixa penetração das moléculas do solvente no filme interfacial e ao efeito de blindagem das repulsões eletrostáticas entre os grupos polares. O efeito da quantidade de PRS em relação a AOT foi estudado por SANS, e observou-se que o aumento da curvatura está diretamente ligada à valência do contra-íon do PRS. Nestes sistemas, a excitação da banda de transferência de carga metal-ligante, LMCT, leva a uma transferência de elétrons do PRS para seu respectivo contra-íon, promovendo a geração de nanopartículas metálicas e de óxidos metálicos nas micelas invertidas. Neste trabalho, é apresentada a prova do conceito do uso de PRS como precursor na síntese fotoquímica de nanopartículas inorgânicas aproximadamente monodispersas. Foram obtidas nanopartículas de Co3O4 e Bi em altas concentrações (10-2 M) pela irradiação das micelas invertidas com luz UV sem a presença de agentes redox ou outras moléculas. O método também se mostrou eficaz para a síntese de óxido de ferro, óxido de cério e óxido de manganês. Estes resultados demonstram que estes sistemas são uma nova abordagem na síntese de nanomateriais em sistemas auto-ordenados fotossensíveis, representando uma rota limpa, direta e simples para síntese de materiais.
Figueiredo, Leandro Carlos. "Sistemas magnéticos nanoparticulados à base de maghemita." reponame:Repositório Institucional da UnB, 2009. http://repositorio.unb.br/handle/10482/4868.
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Este trabalho apresenta a investigação das propriedades magnéticas de fluido magnético iônico contendo nanopartícula de maghemita ( -Fe2O3). Ademais, apresenta a investigação das propriedades magnéticas do sistema constituído de nanocápsulas de albumina contendo nanopartículas de maghemita, inseridas na matriz polimérica via o fluido magnético iônico. As técnicas utilizadas para a investigação foram técnicas de ressonância magnética eletrônica, magnetização e birrefringência magnética estática. Primeiramente, foram estudadas as características estruturais das nanopartículas de maghemita utilizando-se técnicas de difração de raios-X e microscopia eletrônica de transmissão. As nanopartículas (nanocápsulas) magnéticas apresentam diâmetro médio e dispersão em diâmetro de 8,15 nm e 0,30 (73 nm e 0,37), respectivamente. Os dados de ressonância magnética foram tratados considerando que partículas com diâmetros levemente maiores que a média apresentam absorção ressonante em campo inferior ao máximo de absorção. Por outro lado, partículas menores apresentam absorção em campo superior. Considerando as características da variação da largura de linha de ressonância com a temperatura e com a orientação da amostra congelada (dependência angular), verifica-se que as partículas menores são as que sofrem maior influência decorrente do efeito das interações. A magnetização foi estudada para o sistema de nanocápsulas magnéticas considerando a implementação de um modelo de barreira de energia que inclui termos para descrever os fenômenos de interação entre as partículas. Os resultados sugerem que as interações entre as partículas são responsáveis pelas variações no perfil das curvas de histerese obtidas em diferentes temperaturas. Uma assinatura relacionada à susceptibilidade magnética da amostra em função da temperatura foi observada na evolução do perfil das interações. Verifica-se, ainda, que a implementação do modelo se aplica a outros sistemas de nanopartículas magnéticas. Por fim, os resultados de birrefringência magnética estática foram analisados considerando os mesmos argumentos utilizados no modelo de avaliação dos dados de magnetização. Valores da concentração de partículas e frações de agregados que contribuem para a birrefringência foram calculados. __________________________________________________________________________________________ ABSTRACT
This work presents the investigation of magnetic properties of an ionic magnetic fluid containing maghemite (y-Fe2O3) nanoparticles. Moreover, this work presents the investigation of the magnetic properties of the system consisting of albumin nanocapsules containing maghemite nanoparticles embedded in the polymer matrix via the ionic magnetic uid. The techniques used in our investigation were magnetic resonance, magnetization and static magnetic birefringence. Firstly, we investigated the structural characteristics of the maghemite nanoparticles using X-ray di raction and transmission electron microscopy. Nanoparticles and (nanocapsules) were found to present average diameter and diameter dispersion of 8.15 nm and 0.29 (73 nm and 0.37), respectively. The magnetic resonance data were analyzed considering that particles with a diameter slightly larger than the average size present resonant absorption eld smaller than the eld for maximum absorption. On the other hand, smaller particles present resonant absorption at elds above the eld for maximum absorption. Given the characteristics of both the temperature dependence of the resonance linewidth and the resonance parameters of eld-frozen samples (angular dependence measurements) it appears that smaller particles are subjected to stronger in uence due to the e ect of particle-particle interaction. The magnetization data of magnetic nanocapsules were analyzed considering an energy barrier model including terms to describe the interaction among the supported magnetic particles. The results suggest that interactions between particles are responsible for changes in the pro le of hysteresis curves at di erent temperatures. A signature related to the particle interaction was observed in the temperature dependence of the magnetic susceptibility. We found, in addition, that the model used to analyze our magnetization data applies to other systems containing magnetic nanoparticles. Finally, the static magnetic birefringence data were analyzed considering the same arguments used in the analysis of the magnetization data. Values of particles concentration and fractions of aggregates contributing to the birefringence signal were determined.
Singh, Pankaj Kumar. "Dispersion of nanoparticulate suspensions using self-assembled surfactant aggregates." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1001182.
Full textConvery, Joanne Marie. "Analysis of nanoparticulate coatings with relevance to dentine sensitivity." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501564.
Full textPalgrave, Robert. "Chemical vapour deposition of nanoparticulate and nanocomposite thin films." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1444997/.
Full textKroner, Anna Barbara. "Effect of ceria and zirconia on nanoparticulate rhodium catalysts." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/67241/.
Full textBalbinot, Carlos Eduardo Agostini. "Avaliação de propriedades mecânicas de resinas compostas nanoparticuladas." Pontifícia Universidade Católica do Rio Grande do Sul, 2006. http://hdl.handle.net/10923/482.
Full textThe purpose of this study was evaluate selected mechanical properties (compressive strength, diametral tensile strength, flexural strength e flexural moduli) of four differents nanofilled composite and a microhybrid composite, in dentin e enamel A2 shades. Were maded ten samples for each group of each test. The flexural moduli was calculated by the results of the flexural strength`s test. The results were compared statistically with ANOVA e Tukey (p<0,01). There was no statistical difference for compressive strength, with values that range into 141. 04 MPa for 4 Seasons A2E and 206. 08 MPa Grandio A2O. For flexural strength, there was statistical difference for the tested groups, and the values range into 59. 16 MPa for 4 Seasons A2E and 122 MPa for Supreme XT A2E. There was statistical difference for flexural moduli and in this test the values range between 3. 4 GPa for 4 Seasons A2E and 13. 30 GPa for Grandio A2O. For diametral tensile strength, Esthet-X A2O showed value (34. 87 MPa) statiscally lower than the others groups, and Supreme XT A2E (50. 26 MPa), statiscally higher than the others tested groups; between the others groups there was no statistical difference. Even with differences for the values between the tested groups for flexural strength, flexural moduli and diametral tensile strength, the nanofiller composites, based in the results of this study, present mechanical properties similar from microhibrid resin.
Este estudo teve como objetivo avaliar as propriedades mecânicas selecionadas (resistência à compressão, resistência à tração diametral, resistência flexural de trêspontos e módulo flexural) de quatro marcas diferentes de resina composta nanoparticuladas e uma resina composta microhíbrida, nas cores A2 esmalte e dentina. Foram confeccionadas dez amostras para cada grupo de cada teste. O módulo flexural foi calculado a partir dos resultados do teste de resistência flexural. Os resultados obtidos nos ensaios foram comparados estatisticamente com análise de variância e teste de Tukey (p < 0,01). Não houve diferença estatisticamente significante para os grupos testados no teste de resistência à compressão, sendo que as médias variaram entre 141,04 MPa para a resina 4 Seasons A2E e 206,08 MPa para a resina Grandio A2O. No teste de resistência flexural, houve diferença estatisticamente significativa entre os grupos, onde as medias variaram entre 59,16 MPa para a resina 4 Seasons A2E e 122 MPa para a resina Supreme XT A2E. Houve diferença estatisticamente significante para módulo flexural e neste teste as médias variaram entre 3,4 GPa para a resina 4 Seasons A2E e 13,30 GPa para a resina Grandio A2O. No teste de resistência à tração diametral, a resina Esthet-X A2O apresentou média (34,87 MPa) estatisticamente menor que os demais grupos, e a resina Supreme XT A2E (50,26 MPa), estatisticamente maior que os demais grupos testados; entre os demais grupos não houve diferença estatisticamente significante. Apesar de diferenças nos valores entre os grupos testados nos testes de resistência flexural, módulo flexural e resistência à tração diametral, as resinas nanoparticuladas, baseados nos resultados obtidos neste estudo, apresentam propriedades mecânicas semelhantes da resina microhíbrida.
Costa, Inês Henriques da Silva e. "Nanotoxicologia: métodos para avaliação do perfil toxicológico de sistemas nanoparticulares." Master's thesis, [s.n.], 2013. http://hdl.handle.net/10284/4085.
Full textA nanotecnologia é uma ciência promissora em diversas áreas, incluindo a indústria farmacêutica, na qual o seu principal objetivo é o desenvolvimento de novas terapias. As nanopartículas lipídicas sólidas (SLN) foram desenvolvidas com o objetivo de ultrapassar os limites dos sistemas coloidais tradicionais como lipossomas, emulsões e as nanopartículas poliméricas. São partículas com tamanhos inferiores ao mícron, entre 50-1000nm, constituídas por lípidos fisiológicos, biodegradáveis, e biocompatíveis, que se mantêm sólidos à temperatura corporal e ambiente. Neste projeto é abordada a nanotecnologia associada a estas partículas, como os excipientes utilizados, os métodos de produção, as suas principais aplicações e a sua toxicidade. Apesar destas nanopartículas apresentarem todos os pré-requisitos para serem considerados sistemas de transporte seguros, sendo esperada baixa ou até nenhuma toxicidade, a sua utilização médica requer mais evidência sobre a sua segurança. A maioria dos dados disponíveis na literatura sobre o comportamento destas partículas in vitro parece confirma-la, mas alguns resultados discordantes também já foram apresentados. O stress oxidativo é um dos danos mais largamente associados às nanopartículas, mas nas SLN este efeito não tem tido amplamente estudado. Os poucos estudos realizados revelam resultados contraditórios, o que nos incentivou a averiguar a possível indução de stress oxidativo por uma série de cSLN em HepG2, uma linha celular do carcinoma hepatocelular. Averiguámos a geração de espécies reativas de oxigénio (ROS) e a alteração na atividade dos sistemas antioxidantes enzimáticos após exposição às cSLN. O ensaio de DCFH-DA revelou um enorme aumento da presença ROS, a atividade da superóxido dismutase aumentou e a atividade da glutationa redutase diminuiu drasticamente (início de apoptose), o que nos indica que estas nanopartículas causam, realmente, stress oxidativo nesta linha celular. Em adição, investigámos se tal toxicidade é causada pelo lípido catiónico usado nas formulações em causa (brometo de cetiltrimetilamônio, CTAB). Os resultados direcionam-no como uma razão para tal toxicidade, mas não a única. Contudo, os nossos resultados foram contraditórios e mais investigação deve ser levada a cabo. Nanotechonology is a promising science in several fields, including the pharmaceutical industry, in which its main goal is to develop new therapeutics. Solid lipid nanoparticles (SLN) were developed to overcome the limits of traditional colloidal carriers such as liposomes, emulsions and polymeric nanoparticles. They are submicron particles with size in the range of 50-1000 nm and are composed of physiological, biodegradable and biocompatible lipids that remain solid at body and room temperature. In this thesis it is described the nanotechnology associated to SLN, materials used as excipients, methods of production, their main applications and their toxicology. Although these particles present all pre-requisites to be considered safe drug carries, being expected to present low or even none toxicity, their use in medicine requires more evidence of their safety. The available data on the in vitro behavior of these systems seem to confirm it, but some contradictory results have also been reported. Oxidative stress is one of the most reported damage associated to nanoparticles, but in SLN it has not been widely studied. The few performed studies have revealed some contradictory result, which led us to study the possibility of oxidative stress induction by a set of cSLN in HepG2, a human hepatocellular carcinoma cell line. We ascertained the generation of reactive oxygen species (ROS) and the alteration on antioxidant enzymes’ activity after exposure to the cSLN. DCFH-DA assay revealed great increase of ROS presence, the activity of superoxide dismutase was increased and the activity of gluthatione redutase was largely decreased (apoptosis initiation), indicating that these nanoparticles caused, indeed, oxidative stress in this cell line. In addition, we investigated if such toxicity is caused by the cationic lipid used in the formulations (cetyl trimethylammonium bromide, CTAB), our main suspect. The results direct it as one, but not the only, reason of such toxicity. Nevertheless, our results were contradictory and more investigations must be carried out.
Smith, Bryan Ronain. "Nanoparticulate platforms for molecular imaging of atherosclerosis and breast cancer." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1150309580.
Full textLibor, Zsuzsanna. "Chemical synthesis of nanoparticles and electrohydrodynamic manipulation of nanoparticulate suspensions." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4486.
Full textSommer, Katherine. "Nanoparticulate copolymers for the encapsulation and release of bioactive molecules." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606942.
Full textCousins, Brian G. "The effect of a nanoparticulate silica coating on cellular response." Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420280.
Full textEmamzadeh, Mina. "Polymer-gold nanoparticulate formulations for combinational photochemotherapy of pancreatic cancer." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10059498/.
Full textBenin, Bogdan Markovich. "Synthesis and Characterization of Novel Gold-Based Nanoparticulate Chemotherapeutic Agents." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1461088605.
Full textMurshidi, Julie Andrianny. "Hydrogen storage studies of nanoparticulate AI and TiMn based compounds." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/175.
Full textSaleh, Yara. "Etude de la pathogénicité pulmonaire des polluants atmosphériques nanoparticulaires." Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S014.
Full textBackground: Air pollution is one of the leading causes of premature death worldwide. Among air pollutants, particulate matter (PM) is a major health risk factor, through the development of pulmonary diseases. The toxicity of PM depends on their chemical composition and size which increases their mutagenic and/or carcinogenic properties and determine their penetration and retention in the respiratory tract. Fine particles (FP <2,5μm) and ultrafine particles (UFP <0,1μm) can thus reach the deepest airways where their purification will be carried out slowly by macrophage clearance. Compared to FP, less is known about the toxicological impact of UFP.Methods: We first compared the impact of prolonged exposure to PF and PUF collected on the same urban-industrial site on the respiratory health in mice. After physicochemical characterization of the particles (granulometry, surface composition, elementary composition, PAH), BALB/c mice were intranasally exposed to increasing single doses of PF or PUF (10, 50 or 100 μg) and subchronically for 1 month or 3 months, to 3 doses of 10 μg of particles per week. Mice were then sacrificed, bronchoalveolar lavages (BAL) were performed and different samples (blood, lungs, liver, femurs) were taken for toxicological analyses.Results: The elemental chemical composition of FP and UFP did not show any major differences but highlights their industrial origin due to their high content of metals. On the other hand, a slightly higher PAH content was detected in FP compared to PUF. For all experimental conditions, no in vivo genotoxic and / or mutagenic effects were detected (comet, micronucleus, Pig-A negative tests). However, the study of the cellularity of BAL, the quantification of cytokine gene expression and histological analysis of lung tissue suggest the occurrence of chronic inflammation in exposed mice lungs. More extended lesioned areas were, however, observed in the UFP-exposed mice. Transcriptomic analyses have shown, on the one hand, that the number of deregulated genes increases with the dose and the time of exposure, and on the other hand that this number is much higher in mice exposed to UFP compared to those exposed to FP. The identification of the main signalling pathways most5significantly impacted confirms that UFP induce greater and earlier lung tissue response than PF. Concerning the epigenetic analyses, deregulation of DNA methylation, histone modifications, and gene expression of some miRNAs was more pronounced in PUF-exposed mice. The ongoing functional analysis of miRNAs specifically deregulated by PUFs, or commonly deregulated by PUFs and PFs, should allow the identification of their target mRNAs.Conclusion: The results of this study suggest that UFP have greater impact on the respiratory system than FPs which would allow the identification of new biomarkers of tissue damage. The information resulting from this project can be transmitted to the different organizations in charge of air pollutants and their effects on health, to the concerned authorities and to the industries in order to contribute to make better decisions regarding the reduction of emissions of particulate pollutants of greatest concern. They will thus help to update the current regulations in order to include UFP and limit their emissions
David, Cintia de. "Detecção de nano-partículas calcificantes (NPC) em materiais biológicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/8667.
Full textNanobacteria (NB) are unconventional agents, 100 to 1000-fold smaller than common bacteria; furthermore, their multiplication rate is very slow, making their detection difficult using standard microbiological methods. These structures have been isolated as from environment as human and animal blood and urine. They produce a carbonate apatite (calcium phosphate) layer and they have been associated to kidney stone formation and other pathological calcifications. The aims of this study were analyze various biological materials using different methods to verify the presence of these structures morphologically similar to NB, named as Calcifing Nano-Particles (CNP), and to develop an ELISA test to detect antibodies against these structures. The samples were analyzed using optical microscopy, scanning electron microscopy, indirect immunofluorescence and enzyme-linked immunossorbent assay (ELISA). The optical and electron microscopy allowed us to observe particles with morphology closely similar to NB on cell lineages, commercial fetal bovine sera and human kidney stones samples. Using sera collected from animal immunized with CNP, preliminary results displayed a good specificity of ELISA test.
Zampiva, Rubia Young Sun. "Síntese e dopagem com érbio de forsterita nanoestruturada e sua caracterização microestrutural e de propriedades óticas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/169760.
Full textForsterite is a ternary oxide that belongs to the olivine mineral group. Its empirical formula is Mg2SiO4, mainly consisting of SiO44- anions and Mg2+ cations in the molar ratio of 1: 2. The structure of Mg2SiO4 consists of isolated (SiO4)4-tetrahedra, where each of the tetrahedral oxygens is shared by three octahedral cations (MgO6). The octahedral sites have two non-equivalent crystallographic conformations, one being larger and less organized relativily to the other, and both sites can be replaced by ions such as transition metals and rare earths. This structural conformation makes forsterite a promising host for optical applications. Among rare earths, the erbium, which is already widely applied in telecommunications, stands out. The Er3+ ion presents the upconversion phenomenon (absorption of two photons of lower energy, with emission in higher energy regions) when excited in the near infrared with emission in the UV-vis, keeping the upconversion property as dopant in different hosts. According to the host, the absorption and emission lines can vary in intensity and position in the spectrum. In other words, the dopant ion can present distinct optical properties depending on the host in which it is inserted. Based on the forsterite and erbium properties, this present thesis proposes the synthesis of erbium doped forsterite nanostructures (nanoparticles, nanofilms, one-dimensional structures and bulk from nanoparticles) for application in three different emerging fields: Biomedicine, clean energy and solid state lasers with applicability in macro and nanodevices. The Mg2SiO4: Er3+ system is presented for the first time in this thesis, for the best of our knowledge. The upconversion and downconversion analyses for all erbium concentrations studied in this system showed activity in the optical range of interest of the suggested applications. These results, combined with the possibility of low cost production with high quality, quantity and reproducibility make the Mg2SiO4: Er3+ system a material with potential for industrial application.
Brunner, Tobias J. "Application of nanoparticulate biomaterials for injectable bone cements and dental repair." kostenfrei kostenfrei, 2007. http://e-collection.ethbib.ethz.ch/view/eth:30076.
Full textAdisa, Akintayo Oluwole. "Deposition on nanoparticulate metals at the liquid/liquid and templated interface." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498795.
Full textHall, M. "Design and evaluation of nanoparticulate delivery systems for prodrugs of fluorouracil." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398106.
Full textHapuarachchi, Tharindu Dhanushka. "Development and characterisation of flame retardant nanoparticulate bio-based polymer composites." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/532.
Full textSmith, Graeme. "Degradation of the nanoparticulate Pt/C air cathode by cyclic thermammetry." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610273.
Full textYaa, Asantewaa. "Development of a chitosan based glucose responsive nanoparticulate insulin delivery system." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14204/.
Full textMännl, Ulrich Philipp. "Electronic properties and microstructure of nanoparticulate silicon systems for diode applications." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/12978.
Full textIn printed electronics the use of semiconducting silicon nanoparticles allows more than the simple printing of conductive materials. It gives the possibility of fabricating robust and inexpensive, active components. This work presents the design, fabrication, and characterization of Schottky barrier diodes using silicon nanoparticulate composites. Within this work it could be shown, that silicon nanoparticles produced by high energy milling can be used to replace the pigment in water-based graphic inks, which on curing have unique semiconducting properties, arising from the transport of charge through a percolation network of crystalline silicon nanoparticles. In this thesis scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and mid-infrared scanning near-field optical microscopy (IR s-SNOM) were employed to investigate the micro-scale as well as the meso-scale structure of the printed particle networks and, more importantly the structure of the interface between particles. A close contact between lattice planes of different particles was observed, without the presence of a thick intervening oxide layer. Altogether, the results presented in this thesis suggest that highly doped silicon nanoparticles produced by high energy milling are suitable to be used for Schottky barrier diodes fabricated by screen printing. The saturation current of the diodes was about 0.11µA for reverse bias voltages up to 5V with an ideality factor of 10.6, and rectification ratios of approximately 10⁴ were observed.
Kandanapitiye, Murthi S. "Synthesis of Biocompatible Nanoparticulate Coordination Polymers for Diagnostic and Therapeutic Applications." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1429019837.
Full textFreitas, Jilian Nei de. "Celulas fotovoltaicas hibridas de polimeros condutores e nanoparticulas inorganicas." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248441.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Este trabalho consistiu no desenvolvimento e caracterização de materiais para aplicação em células fotovoltaicas híbridas. No Capítulo I, uma introdução geral sobre o funcionamento e estado da arte de células solares, e sobre as propriedades de polímeros condutores e nanopartículas inorgâncias é apresentada. O Capítulo II contém os objetivos deste trabalho. No Capítulo III, foram investigados novos polímeros condutores, baseados na combinação de unidades fluoreno com unidades tiofeno e/ou benzeno. As propriedades fotofísicas, eletroquímicas e de transporte de cargas foram caracterizadas, e esses polímeros foram então combinados com um derivado solúvel de fulereno (PCBM) e os compósitos formados (heterojunção) foram aplicados em células solares com configuração ITO | PEDOT:PSS | Heterojunção | LiF | Al. A seguir, foram sintetizadas nanopartículas de CdSe com diferentes tamanhos, usando um método descrito na literatura. Essas partículas foram caracterizadas por medidas de absorção e emissão, voltametria cíclica (VC), difração de Raios-X (DRX) e microscopia eletrônica de transmissão (TEM), conforme apresentado no Capítulo IV. Os polímeros investigados inicialmente foram combinados com as nanopartículas de CdSe, e esses materiais foram utilizados na montagem de células solares híbridas. De modo geral, os dispositivos apresentaram valores baixos de fotocorrente, o que foi atribuído ao fato de as nanopartículas inorgânicas não transportarem elétrons de forma efetiva nesses dispositivos. A seguir, propôs-se um novo sistema, em que a heterojunção constitui na mistura ternária polímero/CdSe/PCBM. Esses dispositivos foram caracterizados por curvas de corrente-potencial e pela resposta espectral do sistema, mostrando resultados extremamente promissores. Os sistemas ternários foram então investigados por diversas técnicas, como absorção, emissão, DRX, VC, TEM e microscopia de força atômica, a fim de determinar a atuação de cada componente da mistura ternária quando aplicados nas células solares. Esses resultados são apresentados no Capítulo V. No Capítulo VI, novos polímeros condutores derivados do polifluoreno, contendo unidades funcionais como grupos piridina, ou compostos aromáticos do tipo "push-pull", foram sintetizados pelo método de Gilch. A estrutura desses polímeros foi desenhada visando sua aplicação nas células híbridas, combinandoos com as nanopartículas de CdSe previamente sintetizadas. Esses materiais foram caracterizados por ressonância magnética nuclear de hidrogênio, espectroscopia no Infravermelho com transformada de Fourier. cromatografia por permeação em gel, análises térmicas e medidas eletroquímicas e de fotofísica. No Capítulo VII, propôs-se a introdução de um corante orgânico comercial (Disperse Red 1), como terceiro componente em uma mistura de poli(fluorenilenovinileno) e PCBM, visando aumentar a absorção de luz pela camada ativa do dispositivo. Foi realizado um extenso estudo usando técnicas fotofísicas e eletroquímicas para investigar o efeito da adição do corante, bem como determinar quais os tipos de processos (transferência de elétrons ou energia) ocorrem no sistema ternário. Finalmente o Capítulo VIII contém as principais conclusões deste trabalho e perspectivas de continuação para esta linha de pesquisa.
Abstract: This PhD Thesis investigated the development and characterization of new materials aiming at the application in hybrid solar cells. In Chapter I, a general introduction on the working principles and state-of-the-art of the organic solar cells, properties of the conducting polymers and the inorganic nanoparticles are presented. Chpater II highlights the aims of this work. In Chapter III, new conducting polymers based on the combination of fluorene, thiophene and/or benzene units are investigated. The photophysical and electrochemical characteristics, and charge mobility, are discussed. The polymers were also combined with a soluble fullerene derivative (PCBM) and these composites were used as active layer in bulk-heterojunction solar cells with the following configuration: ITO | PEDOT:PSS | Heterojunction | LiF | Al. Then, CdSe nanoparticles with different sizes were synthesized using a well-established method, and characterized using absorption and emission measurements, cyclic voltammetry (CV), X-ray diffraction (XRD) and transmission electron microscopy (TEM), as presented in Chapter IV. The previously characterized polymers were combined with the CdSe nanoparticles, and the nanocomposites were used to assemble hybrid solar cells. The devices showed very low photocurrent values, which were attributed to a poor electronic transport in the nanoparticles phase. Thus, a new system was suggested, based on a mixture of polymer/CdSe/PCBM. The photocurrent-potential curves and spectral response of the devices assembled with the ternary systems were evaluated, leading to very promising results. The absorption, emission, XRD, CV, TEM and atomic force microscopy measurements of the films were also performed to investigate/elucidate the role of each component in the ternary systems, as discussed in Chapter V. In Chapter VI, new conducting polymers based on poly(fluorenylenevinylene) containing functional units, such as pyridine or push-pull type aromatic units, were synthesized via the Gilch route. The structures of these materials were designed aiming at their application in hybrid solar cells, in combination with the previously synthesized CdSe nanoparticles. The polymers were characterized by magnetic nuclear resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermal, electrochemical and photophysical measurements. These polymers were combined with CdSe and/or PCBM and used as active layer in solar cells. In Chapter VII the addition of the commercial organic dye Disperse Red 1 in the mixture of poly(fluorenylenevinylene)/PCBM to enhance the light absorption in the active layer was investigated. A systematic study using photophysical and electrochemical measurements was performed in order to elucidate the effect of the dye addition, as well as the energy or electron transfer processes in this new ternary system. Finally, Chapter VIII summarizes the main conclusions of this work and highlights some perspectives for this exciting research filed.
Doutorado
Quimica Inorganica
Doutor em Ciências
Guerra, Rubens Antônio. "Estudo da interação de porfirinas com nanoparticulas magnéticas biocompativeis." Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/4479.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
(Sem resumo em outra língua)
O objetivo deste trabalho de mestrado é o estudo das interações entre porfirina de base livre (TMPP) e seu complexo metálico (ZnTMPP) com nanopartículas magnéticas biocompatíveis com diferentes camadas de cobertura. O sistema em estudo mostrou potencial para possíveis aplicações na medicina moderna, particularmente na terapia fotodinâmica ou como marcador fluorescente na magnetohipertermia. O presente sistema foi investigado através do uso de técnicas espectroscópicas de onde foram obtidas constantes de ligação, supressão, anisotropia e constante de velocidade bimolecular.
Mendes, Paulo Gedeão. "ESTUDO DA CINÉTICA DE SINTERIZAÇÃO EM SISTEMAS NANOPARTICULADOS DE SnO2." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2009. http://tede2.uepg.br/jspui/handle/prefix/1443.
Full textSeveral synthesis methods exist for ceramic materials. According to the method of synthesis used to prepare oxide materials different morphologic and microstructural properties can be obtained. This work consisted of studying the Co-doped tin dioxide powders synthetized by microwave-assisted hydrothermal synthesis (MAHS) and the results were compared to powders synthesized by Pechini method. Powders synthesized by MAHS presented size of particles in the order of 5 nm while the size of particles obtained by Pechini was about five times greater. Besides the characterization of those materials in the powder form, the material was compacted and sintered. Sintering at different constant hating rates of constant heating allowed the calculation of the apparent global energy of sintering using the master sintering curve model. The material synthesized by MAHS presented a smaller apparent global energy of sintering than that obtained by Pechini route, and in the same proportion of their size differences. The results of this work lead to the conclusion that the sintering process and the saturation of dopants are strongly influenced by the particle size of starting powders.
Vários são os métodos de síntese dos materiais cerâmicos. Conforme o método de síntese utilizado para preparar materiais óxidos, diferentes serão suas propriedades morfológicas e microestruturais. Este trabalho consistiu em estudar o dióxido de estanho dopado com óxido de cobalto a partir da síntese de hidrotermalização assistida por micro-ondas (HTMW) e os resultados foram comparados aos da síntese via método Pechini. Pós sintetizados via HTMW apresentaram tamanho de partículas da ordem de 5 nm enquanto via Pechini em torno de cinco vezes maior. Além da caracterização desses materiais na forma de pó, o material foi compactado e sinterizado em dilatômetro. A sinterização a partir de diferentes taxas de aquecimento constante tornou possível o cálculo da energia global aparente de sinterização a partir do modelo da curva mestre de sinterização. O material sintetizado via HTMW apresentou energia global aparente de sinterização menor que o sintetizado via Pechini, na mesma proporção de suas diferenças de tamanho. Assim com este trabalho conclui-se que o processo de sinterização e a saturação de dopantes são fortemente influenciados pelo tamanho de partícula do pó de partida.
Balbinot, Carlos Eduardo Agostini. "Avalia??o de propriedades mec?nicas de resinas compostas nanoparticuladas." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2006. http://tede2.pucrs.br/tede2/handle/tede/1173.
Full textEste estudo teve como objetivo avaliar as propriedades mec?nicas selecionadas (resist?ncia ? compress?o, resist?ncia ? tra??o diametral, resist?ncia flexural de tr?spontos e m?dulo flexural) de quatro marcas diferentes de resina composta nanoparticuladas e uma resina composta microh?brida, nas cores A2 esmalte e dentina. Foram confeccionadas dez amostras para cada grupo de cada teste. O m?dulo flexural foi calculado a partir dos resultados do teste de resist?ncia flexural. Os resultados obtidos nos ensaios foram comparados estatisticamente com an?lise de vari?ncia e teste de Tukey (p < 0,01). N?o houve diferen?a estatisticamente significante para os grupos testados no teste de resist?ncia ? compress?o, sendo que as m?dias variaram entre 141,04 MPa para a resina 4 Seasons A2E e 206,08 MPa para a resina Grandio A2O. No teste de resist?ncia flexural, houve diferen?a estatisticamente significativa entre os grupos, onde as medias variaram entre 59,16 MPa para a resina 4 Seasons A2E e 122 MPa para a resina Supreme XT A2E. Houve diferen?a estatisticamente significante para m?dulo flexural e neste teste as m?dias variaram entre 3,4 GPa para a resina 4 Seasons A2E e 13,30 GPa para a resina Grandio A2O. No teste de resist?ncia ? tra??o diametral, a resina Esthet-X A2O apresentou m?dia (34,87 MPa) estatisticamente menor que os demais grupos, e a resina Supreme XT A2E (50,26 MPa), estatisticamente maior que os demais grupos testados; entre os demais grupos n?o houve diferen?a estatisticamente significante. Apesar de diferen?as nos valores entre os grupos testados nos testes de resist?ncia flexural, m?dulo flexural e resist?ncia ? tra??o diametral, as resinas nanoparticuladas, baseados nos resultados obtidos neste estudo, apresentam propriedades mec?nicas semelhantes da resina microh?brida
Boita, Jocenir. "Estudos in situ da formação de compostos de cobre nanoparticulados." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/21698.
Full textIn this work, we have monitored the formation of copper based aggregates (micro and nano sized) in aqueous solution using the DXAS in situ technique (dispersive x-ray absorption spectroscopy), in the time resolved mode. A crucial part of this work was the development of a dedicated reactor for the in situ experiments. The XAS spectra showed the evolution of the structural and electronic properties around the copper atoms, from the ions in solution until the formation of the aggregates. A correlation between the results obtained by DXAS and by other characterization methods (SEM, XRD, XPS) was established. The work developed in this dissertation will contribute for future investigations of the processes involved in the formation of nanoparticles in solution, which may be applied for catalysts, fuel cells and biosensors.
Gallardo, Marie-Madeleine. "Caractérisations physico-chimiques de systèmes nanoparticulaires de polyisobutyl-2-cyanoacrylate." Paris 11, 1991. http://www.theses.fr/1991PA114816.
Full textSharma, Ankur. "Development of nanoparticulate drug delivery systems for anti-metastatic Ran GTPase therapeutics." Thesis, Ulster University, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.725342.
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