Xian'e Li (IMAGE) Linköping University Caption Xian’e Li, a PhD student at Linköping University and principal author of the scientific article. Credit Thor Balkhed Usage Restrictions Please use appropriate caption and credit. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.