c1 Refereed Journal Article. Green in Sherpa. 
Author's Pre-print:author can archive pre-print (ie pre-refereeing) Author's Post-print: author can archive post-print (ie final draft post-refereeing) Publisher's Version/PDF: archiving status unknown. MA 18/11/13 & 21.8.14-MMM, Requested (Yanchun) Accepted v. & Permission, 21.8.14-MMM. Tao Xuehong has signed permission & file supplied, 4.9.14-MMM. Supporting documentation added to dark upload - HD 5/6/18.  HERDC documentation added to dark upload - HD 14/5/20