Síntese e caracterização de CuNb2O6 e CuNbC através de reação sólido- sólido e gás- sólido a baixa temperatura

The refractory metal carbides have proven important in the development of engineering materials due to their properties such as high hardness, high melting point, high thermal conductivity and high chemical stability. The niobium carbide presents these characteristics. The compounds of niobium impregnated with copper also have excellent dielectric and magnetic properties, and furthermore, the Cu doping increases the catalytic activity in the oxidation processes of hydrogen. This study aimed to the synthesis of nanostructured materials CuNbC and niobium and copper oxide from precursor tris(oxalate) oxiniobate ammonium hydrate through gas-solid and solid-solid reaction, respectively. Both reactions were carried out at low temperature (1000°C) and short reaction time (2 hours). The niobium carbide was produced with 5 % and 11% of copper, and the niobium oxide with 5% of copper. The materials were characterized by X-Ray Diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), X-Ray Fluorescence Spectroscopy (XRF), infrared spectroscopy (IR), thermogravimetric (TG) and differential thermal analysis (DTA , BET and particle size Laser. From the XRD analysis and Rietveld refinement of CuNbC with S = 1.23, we observed the formation of niobium carbide and metallic copper with cubic structure. For the synthesis of mixed oxide made of niobium and copper, the formation of two distinct phases was observed: CuNb2O6 and Nb2O5, although the latter was present in small amounts

Estudo da síntese e propriedade magnética de ferritas de manganês/cobalto dopadas com níquel

For the chemical method of synthesis of co-precipitation were produced ferrite powders manganese-cobalt equal stoichiometric formula Mn (1-x) Co (x) Fe2O4, for 0 < x < 1, first reagent element using as the hydroxide ammonium and second time using sodium hydroxide. The obtained powders were calcined at 400 ° C, 650 ° C, 900 ° C and 1150 ° C in a conventional oven type furnace with an air atmosphere for a period of 240 minutes. Other samples were calcined at a temperature of 900 ° C in a controlled atmosphere of argon, to evaluate the possible influence of the atmosphere on the final results the structure and morphology. The samples were also calcined in a microwave oven at 400 ° C and 650 ° C for a period of 45 minutes possible to evaluate the performance of this type of heat treatment furnace. It was successfully tested the ability of this group include isomorphic ferrite with the inclusion of nickel cations in order to evaluate the occurrence of disorder in the crystalline structures and their changes in magnetic characteristics.To identify the structural, morphological, chemical composition and proportions, as well as their magnetic characteristics were performed characterization tests of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDX), thermogravimetric (TG), vibrating sample magnetometry (MAV) and Mössbauer spectroscopy. These tests revealed the occurrence of distortion in the crystal lattice, changes in magnetic response, occurrence of nanosized particles and superparamagnetism

Síntese e caracterização de nanocompósitos magnéticos empregando polimerização radicalar em meios homogêneo (blk) e heterogêneo (miniemulsão)

Tese (doutorado)—Universidade de Brasília, Instituto de Química, Curso de Pós-Graduação em Química, 2016.

Multifuncionalização de nanopartículas de CoFe2O4 pela incorporação da prata na sua superfície : síntese e caracterização

Tese (doutorado)—Universidade de Brasília, Instituto de Física, 2015.

Filmes formados pelo copolímero SEBS e nanopartículas de óxidos de ferro : preparação e caracterização

Dissertação (mestrado)—Universidade de Brasília, Instituto de Física, Programa de Pós-Graduação em Física, 2016.

A qualidade da comunicação dos técnicos e auxiliares de ressonância magnética num serviço de radiologia: um programa de intervenção

O presente estudo preliminar teve como finalidade analisar a qualidade da comunicação dos técnicos e auxiliares de ação médica nos exames de Ressonância Magnética, partindo da observação da linguagem verbal e não-verbal. Por analogia com outros domínios, desenvolveu-se um programa de intervenção que incidiu na formação dos técnicos e auxiliares ação médica do Serviço de Radiologia de um hospital público. Recorrendo a uma grelha de observação, avaliou-se o efeito do treino de competências no aumento dos comportamentos adequados durante as Ressonâncias Magnéticas. De uma forma geral, os resultados analisados demonstraram que a formação teve um efeito significativo nos técnicos e nos auxiliares das ressonâncias magnéticas, originando mudanças positivas no local de trabalho, tal como o desenvolvimento de uma relação mais adequada com os doentes que potencie o sucesso do diagnóstico; "Analysis of communication quality of technicians and auxiliaries of MRI radiology service" Abstract: With this preliminary study, we intented to analyze the quality of communication in magnetic resonance imaging exams, starting from the observation of verbal and non-verbal language. By analogy with other areas, it was developed an intervention program focused on the training of technicians and operational assistants of the Radiology service of public hospital. Using a grid note, we assessed the effect of skills training in the increased of appropriate behaviour during the MRIs. In General, the results examined showed that the training had a significant effect on operational assistants and technicians of MRIs, resulting in positive changes in the workplace, such as developing a proper relationship with patients to promote the success of the diagnosis.