6 research outputs found
Structure and phase stability of nanocrystalline Ce1âxLnxO2âx/2âÎŽ (Ln = Yb, Lu) in oxidizing and reducing atmosphere
The structure and phase evolution of nanocrystalline Ce1âxLnxO2âx/2âÎŽ (Ln = Yb, Lu, x = 0 â 1) oxides upon heating in H2 was studied for the first time. Up to 950 °C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 °C in the air and H2, phase separation into coexisting F- and C-type structures was observed for ~0.40 < x < ~0.70 and ~0.25 < x < ~0.70, respectively. It was found also that addition of Lu3+ and Yb3+ strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 °C in both atmospheres. Valency of Ce and Yb in Ce0.1Lu0.9O1.55âÎŽ and Ce0.95Yb0.05O1.975âÎŽ samples heated at 1100 °C was studied by XANES and magnetic measurements. In the former Ce was dominated by Ce4+, with small contribution of Ce3+ after heating in H2. In the latter, Yb existed exclusively as 3+ in both O2 and H2
Lanthanum Molybdate Nanoparticles from the Bradley Reaction: Factors Influencing Their Composition, Structure, and Functional Characteristics as Potential Matrixes for Luminescent Phosphors
The article reflects on the body and on the health and illness process as non-natural facts. Starting from a bibliographic review, it uses some ideas of the history of Western Medicine to contextualize body conceptions, sexual differences, and the health and illness process. In addition, it discusses other medical rationalities and religious cosmologies, in which the conceptions of body, health and illness differ from those of the Western Medicine. It employs some anthropological approaches to show the cultural modeling of the body and its uses; the symbolic dimension and its inclusion in the network of social relations and norms and also its links with the environment and the representations of the person, through ethnographic examples extracted from the literature.O artigo reflete, a partir de revisĂŁo bibliogrĂĄfica, sobre o corpo e o processo saĂșde e doença como fatos nĂŁo naturais. Vale-se de algumas ideias da histĂłria da Medicina Ocidental para contextualizar as concepçÔes do corpo, as diferenças sexuais e a saĂșde e doença, assim como de outras racionalidades mĂ©dicas e cosmologias religiosas onde as concepçÔes do corpo e da saĂșde e doença diferem da medicina ocidental. Recorre a algumas abordagens antropolĂłgicas para mostrar a modelagem cultural do corpo e de seus usos; a dimensĂŁo simbĂłlica e sua emersĂŁo na teia das relaçÔes e normas sociais e nas relaçÔes com o meio ambiente, assim como suas articulaçÔes com a representação da pessoa, atravĂ©s de exemplos etnogrĂĄficos extraĂdos da literatura