1. Dipartimento di Fisica, Universitá di Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli, Italy and CNR-SPIN, UOS Napoli, Piazzale Tecchio 80, 80125 Napoli, Italy
2. IMAST S.c.a.r.l.—Technological District on Engineering of Polymeric and Composite Materials and Structures, Piazza Bovio 22, 80133 Napoli, Italy