ROBERVAL STEFANI
30 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 30
Resumo IPEN-doc 14695 Persistencia luminescente de um silicato dopado com Prsup(3+)2009 - BRITO, HERMI F.; STEFANI, ROBERVAL; CARVALHO, CARLOS A.A.; RODRIGUES, LUCAS C.V.; FELINTO, MARIA C.F.C.; NUNES, LUIZ A.O.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 14679 Color tuning systems of polymer doped with rare earth complexes2009 - KAI, J.; STEFANI, R.; FELINTO, M.C.F.C.; BRITO, H.F.Rare earth complexes were synthesized and doped into polymers resulting in luminescent films. The obtained systems were characterized with elemental analysis, IR, TGA/DTG and XRD techniques. Photoluminescence properties were investigated and processes of energy transfer and sensitization were studied. Monochromatic emissions of obtained polymeric systems enabled their potential applications in multicolor displays because of the primary colors emitted by TR3+: red (Sm3+ and Eu3+), blue (Gd3+) and green (Tb3+). The polymer matrix performs an essential role in the luminescent sensitization processes for systems containing Sm3+, Eu3+, Gd3+ and Tb3+, therefore the overall systems act as Light Conversion Molecular Devices (LCMDs).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 14452 Photoluminescence of aluminium phosphate glasses doped with rare earths2007 - STEFANI, ROBERVAL; RODRIGUES, LUCAS C.V.; CARVALHO, CARLOS A.A.; KAI, JIANG; SANCHES, MARCO A.; FELINTO, MARIA C.F.C.; BRITO, HERMI F.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 14454 Afterglow of Prsup(3+) doped in cadmium silicate2007 - RODRIGUES, LUCAS C.V.; STEFANI, ROBERVAL; CARVALHO, CARLOS A.A.; KODAIRA, CLAUDIA A.; FELINTO, MARIA C.F.C.; BRITO, HERMI F. deResumo IPEN-doc 16633 Spectroscopic studies of CdSiOsub(3):Rsup(3+) persistent luminescence phosphors2010 - RODRIGUES, L.C.V.; BRITO, H.F.; HOLSA, J.; STEFANI, R.; FELINTO, M.C.F.C.; LASTUSAARI, M.Resumo IPEN-doc 16280 Persistent luminescence of barium aluminate doped with Eusup(2+) prepared by the combustion method2008 - RODRIGUES, L.C.V.; STEFANI, R.; CARVALHO, C.A.A.; BRITO, H.F.; KODAIRA, C.A.; FELINTO, M.C.F.C.; HOLSA, J.Resumo IPEN-doc 16283 Encapsulation study of persistent luminescent material in silica2008 - LOURENCO, A.V.S.; RODRIGUES, L.C.V.; KODAIRA, C.A.; STEFANI, R.; CARVALHO, C.A.A.; BRITO, H.F.; FELINTO, M.C.F.C.; HOLSA, J.
- «
- 1 (current)
- 2
- 3
- »