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RESUMO:Os discentes ingressantes no curso de Licenciatura em Química do Campus Professor Alberto Carvalho da Universidade Federal de Sergipe têm apresentado, ao longo dos anos, déficits conceituais e dificuldades de aprendizagem dos conteúdos. Para minimizar essas dificuldades, o Departamento de Química oferece cursos sobre os conhecimentos básicos de Química, os quais são fundamentais para um bom desempenho desses alunos no decorrer do ensino superior nesta área. Dentre esses cursos está o "Pré-química", que usa um modelo inovador bem como facilita a inserção dos ingressos no ambiente universitário. No presente trabalho, analisa-se as contribuições do "Pré-química" para o desempenho dos discentes ingressantes segundo eles próprios.Palavras-chave: "Pré-química"; déficit conceitual; dificuldades de aprendizagem. IN SEARCH OF SOLUTIONS TO PREVENT ESCAPE IN THE EXACT SCIENCE COURSES OF FEDERAL UNIVERSITY OF SERGIPE: REPORTS OF A PROPOSAL FROM CHEMICAL DIVISION ABSTRACT:The students who enter at the course of Chemistry Degree in the campus Professor Alberto Carvalho, at Federal University of Sergipe, have presented, over the years, conceptual deficits and learning disabilities of the subjects. To reducing these difficulties, the Department of Chemistry offers courses on basic knowledge of chemistry, which are essential for a good performance of these students in the higher education in this area. Among these courses is the "pre-chemistry", which uses a teaching innovative model and it facilitates the insertion of the students in the university environment.In this work, we analyze the contributions of the "pre-chemistry" for the performance of the entering students in the course second themselves.

Because of the tunability of properties demonstrated by organic−inorganic hybrid materials, they have attracted considerable attention in recent years. However, despite luminescence being one of the major research topics involving hybrids, SiO 2 −poly(methyl methacrylate) (PMMA) systems have been poorly explored. In this paper, Eu 3+ :SiO 2 −PMMA samples were prepared with different Eu 3+ /Si molar ratios in order to determine Eu 3+ local coordination, the potential interferences of these ions on synthesis reactions and the optimized lanthanide concentration for improved luminescence output. Careful analysis of FTIR spectra showed the presence of Eu 3+ ions coordinated to carbonyl groups in the hybrid matrix, while TG results, allied to FTIR, indicate dopant influence on the mechanisms of formation of polymeric chains. Photoluminescence results showed that, at higher lanthanide contents, the position of the 5 D 0 → 7 F 0 band and spectroscopic parameters are modified, a clear signal of the formation of lanthanide clusters, which results in concentration quenching of luminescence.