Nanopartículas de CeO2 modificadas com Er obtidas pelo método hidrotermal microondas: estudo fotoluminescente

The development of nanostructured materials have aroused great interest of the industries all over the country, since they enable the development of devices that can be used as gate insulators on silicon transistors, electrochromic devices, solid electrolyte oxygen sensors and as a photoluminescent materials . In this project, it is proposed to investigate the optical properties of CeO2 modified with rare earth Er processed in hydrothermal-microwave. The synthesis of one-dimensional nanostructures (1D) was measured from dilute aqueous solutions of acids and salts of starting reagents in the presence of chemical basis, after these aqueous solutions were processed on hydrothermal-microwave to particle growth. The particles obtained after processing were characterized by X-ray Diffraction, Rietveld Analysis and Raman Spectroscopy. The particle morphology was observed by scanning electron microscopy with field emission gun. The synthesis of 1D nanostructures are evaluated for different surfactants and starting precursors (ceria different salts), pH, temperature and pressure which can modify the morphology of the nanostructures. Combining laboratory experiments and theoretical calculations it was desired to understand the organization of the nanoparticles and their resulting structure. Strict control of chemical homogeneity, crystal structure, microstructure and interaction of the CeO2 cluster with different surfactants using the Hartree-Fock method, was intended to obtain properties compatible with their use in catalysts and optical devices. The use of mineralizer agent KOH and 8 minutes of processing time synthesis conditions were chosen to evaluate the effect of Er dopant. It has been proved that this doping with rare earth increases the photoluminescent properties of the compound obtained without change the structural and morphological propreties of ceria

Foto-Geo-Grafia: uma aproximação entre linguagens

Currently we live in an increasingly visual world, where images are used as non-verbal language for different interests. Considering the ease of getting a photograph and the many ways that it can find, understand that this language can be a means of reading the geographic space, appearing as text and not only as illustration for teaching geography. Thus, this work aims to try an approach between artistic photographic language and geographic scientific language, observing how different groups with different ages read the geographic space through photographs. Focusing on the school environment, we have in mind the need to work with the various pictorial means that are increasingly present in textbooks of geography teaching. Here then, as proposed, a trial in which students from elementary and secondary education will shoot what for them is the city. The analysis will be performed observing possible differences and / or common aspects in the photographs according to the age group of students groups, trying to discover how the geographic space is being read by students through images and how this trial can contribute to the basic education of discipline geography