1. State Key Laboratory of Solid LubricationLanzhou Institute of Chemical PhysicsChinese Academy of Sciences Lanzhou 730000 China
2. School of Chemical SciencesUniversity of Chinese Academy of Sciences Beijing 100039 China
3. Laboratory of Solidification ProcessingCenter of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical University Xi'an 710072 China