Open Access
Issue
EPJ Appl. Metamat.
Volume 6, 2019
Article Number 20
Number of page(s) 6
DOI https://doi.org/10.1051/epjam/2019020
Published online 07 November 2019

© Y. Liu et al., published by EDP Sciences, 2019

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.