Photoluminescence of Di-ureasil Hybrids Doped with Au and Ag Silica Coated Nanoparticles C. J. R. Silva, M. J. M. Gomes, V. I. Boev, J.T. Gonçalves, A. Soloviev “Abstracts of the Materiais 2005 /Materials´2005-XII Portuguese Materials Society Meeting and III Materials Synposium SPM” – Universidade de Aveiro, 20-23 de Março de 2005, Aveiro, Portugal, pp.285-286.