1. Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou 730000, China
2. Institute of Solid Mechanics, School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China
3. School of Stomatology, Lanzhou University, Lanzhou 730000, China
4. Department of Stomatology, Traditional Chinese Medicine Hospital of Gansu Province, Lanzhou 730050, China