1. State Key Laboratory of Solid LubricationLanzhou Institute of Chemical PhysicsChinese Academy of Sciences Lanzhou 730000 China
2. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 China
3. Qingdao Center of Resource Chemistry & New MaterialsLanzhou Institute of Chemical PhysicsChinese Academy of Sciences Qingdao 266000 China