1. Department of Biomedical Engineering, School of Medicine, Shenzhen University, Shenzhen 518060, P. R. China
2. Department of Mathematics, COMSATS University Islamabad, Abbottabad Campus, 22060, Pakistan
3. College of Mathematics and Statistics, Shenzhen University, Shenzhen 518060, P. R. China
4. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China