NMR investigation on the occurrence of Na species in porous carbons prepared by NaOH activation - Freitas, Jair Carlos Checon de; Schettino Junior, Miguel A.; Cunha, Alfredo G.; Emmerich, Francisco Guilherme; Bloise, Antonio Carlos; Azevêdo, Eduardo Ribeiro de; Bonagamba, Tito José (Carbon, 2007)