1. Chu Hai College of Higher Education, New Territories, Hong Kong
2. Shandong University, Jinan 250100, China
3. Department of Science and Technology, University of Naples Parthenope, Centro Direzionale, Isola C4, 80134 Naples, Italy
4. University of Rome “Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
5. Missouri University of Science and Technology, Rolla, MO, USA