1. State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences (CAS), Xi’an 710061, China
2. CAS Center for Excellence in Quaternary Science and Global Change, Xi’an 710061, China
3. School of Materials Science and Engineering, Shaanxi Normal University, Xi’an, Shaanxi 710119, China
4. School of Chemistry and Chemical Engineering, Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi’an, Shaanxi 710119, China