ROBERVAL STEFANI
11 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 11
Resumo IPEN-doc 14680 Thermoluminescence and synchrotron radiation studies on the persistent luminescence of BaAlsub(2)Osub(4):Eusup(2+), Dysup(3+)2009 - RODRIGUES, L.C.V.; STEFANI, R.; BRITO, H.F.; FELINTO, M.C.F.C.Barium aluminates doped with Eu2+ and Dy3+ (BaAl2O4:Eu2+,Dy3+) were prepared with the combustion synthesis at temperatures between 400 and 600 °C as well as with the solid state reaction at 1500 °C. The concentrations of Eu2+/Dy3+ (in mole% of the Ba amount) ranged from 0.1/0.1 to 1.0/3.0. The electronic and defect energy level structures were studied with thermoluminescence (TL) and different synchrotron radiation spectroscopies: UV-VUV excitation and emission, XANES and EXAFS. Theoretical calculations using the Density Functional Theory (DFT) were carried out in order to compare with the experimental data.Resumo IPEN-doc 14678 Persistent luminescence BaAlsub(2)Osub(4):Eusup(2+), Dysup(3+) phosphor incorporated in silica: water resistance2009 - LOURENCO, A.V.S.; RODRIGUES, L.C.V.; KODAIRA, C.A.; STEFANI, R.; BRITO, H.F.; FELINTO, M.C.F.C.; HOLSA, J.Barium aluminates doped with divalent europium and trivalent dysprosium were prepared with the combustion method and then incorporated with silica using the microemulsion method. The incorporated phosphor particles showed improved water resistance, preserving much of the prior persistent luminescence properties even after interaction with water whereas the nonincorporated particles loosed the original persistent luminescence. The infrared absorption spectroscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence studies were used to characterize the phosphors. The pH of the phosphor-water mixture after the reaction with water was measured to compare the water resistance of the materials. The photoluminescence of the incorporated BaAl2O4:Eu2+,Dy3+ with water modified slightly the 4f6 5d1 →4f7 transition of Eu2+, however.Resumo IPEN-doc 14453 Long lasting phosphorescence of Eusup(2+) and Dysup(3+) ions doped in barium aluminate2007 - STEFANI, ROBERVAL; RODRIGUES, LUCAS C.V.; CARVALHO, CARLOS A.A.; BRITO, HERMI F.; KODAIRA, CLAUDIA A.; FELINTO, MARIA C.F.C.Resumo IPEN-doc 18731 Cálculos DFT ab initio do BaAlsub(2)Osub(4):Eusub(2+) com luminescência persistente2012 - BRITO, HERMI F.; FELINTO, MARIA C.F.C.; HOLSA, JORMA; LAAMANEN, TANELI; LASTUSAARI, MIKA; MAIKAMAKI, MARJA; NOVAK, PAVEL; RODRIGUES, LUCAS C.V.; STEFANI, ROBERVALResumo IPEN-doc 15522 Afterglow phosphorescence of Basub(4)Alsub(10)Osub(19):Eusup(2+); Dysup(3+) prepared in air2006 - STEFANI, ROBERVAL; MAIA, ALESSANDRA S.; TEOTONIO, ERCULES S.; FELINTO, MARIA C.F.C.; BRITO, HERMI F.Resumo IPEN-doc 12398 Preparacao do aluminato de bario dopado com Eusup(2+), Dysup(3+) com luminescencia persistente utilizando mineralizadores2007 - STEFANI, ROBERVAL; RODRIGUES, LUCAS C.V.; KODAIRA, CLAUDIA A.; FELINTO, MARIA C.F.C.; FALLA, MARIA P.H.; BRITO, HERMI F.Resumo IPEN-doc 12364 Blue luminescent materials containning Eusup(2+) and Dysup(3+) ions doped in barium aluminate? preparation and optical properties2007 - STEFANI, R.; RODRIGUES, L.C.V.; KODAIRA, C.A.; FELINTO, M.C.F.C.; BRITO, H.F.Resumo IPEN-doc 12379 White persistent luminescence of silicates doped with Dysup(3+)2007 - PAOLINI, T.B.; STEFANI, R.; RODRIGUES, L.C.V.; KODAIRA, C.A.; LORENCO, A.V.S.; FELINTO, M.C.F.C.; BRITO, H.F.Resumo IPEN-doc 13581 Persistencia luminosa de MgAlsub(2)Osub(4):Eusup(2+), Dysup(3+) preparado pelo metodo de combustao2008 - STEFANI, ROBERVAL; RODRIGUES, LUCAS C.V.; CARVALHO JUNIOR, JOSE M. de; BRITO, HERMI F.; CARVALHO, CARLOS A.A.; FELINTO, MARIA C.F.C.; KODAIRA, CLAUDIA A.Artigo IPEN-doc 16356 Thermoluminescence and synchrotron radiation studies on the persistent luminescence of BaAlsub(2)Osub(4):Eusup(2+), Dysup(3+)2010 - RODRIGUES, L.C.V.; STEFANI, R.; BRITO, H.F.; FELINTO, M.C.F.C.; HOLSA, J.; LASTUSAARI, M.; LAAMANEN, T.; MALKAMAKI, M.