1. School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
2. Beijing Key Laboratory of Work Safety Intelligent Monitoring, Beijing University of Posts and Telecommunications, Beijing 100876, China
3. Department of Physics, University of Punjab, Quaid-e-Azam Campus, 54590 Lahore, Pakistan
4. Department of Physics, GC University Faisalabad, Allama Iqbal Road, Faisalabad 38000, Pakistan
5. Department of Physics, University of Sargodha, Sargodha 40100, Pakistan
6. Department of Physics, Beijing Institute of Technology, Beijing 10008, China