1. Department of Cultural Heritage and MuseologyZhejiang University Hangzhou 310027 China
2. Department of Materials Science and EngineeringUniversity of California Los Angeles CA 90025 USA
3. Laboratory of Cultural Relic Conservation Materials, Department of ChemistryZhejiang University Hangzhou 310027 China
4. Department of Conservation Management Palace Museum, 4 Jingshan Front Street, Dongcheng District Beijing 100009 China