[1] Univ Pernambuco, Escola Politecn Pernambuco, BR-50720001 Recife, PE, Brazil
[2] Beijing Univ Technol, Coll Econ & Management, Beijing 100124, Peoples R China
[3] Boston Univ, Elect & Comp Engn, Boston, MA 02215 USA
[4] Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA
[5] Boston Univ, Dept Phys, 590 Commonwealth Ave, Boston, MA 02215 USA