c1 Refereed Journal Article. 13.11.13 kq. 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: author cannot archive publisher's version/PDF General Conditions: •Author's pre-print on pre-print servers such as arXiv.org •Author's post-print on author's personal website immediately •Author's post-print on any open access repository after 12 months after publication ... Requested (Yanchun) Accepted v. & Permission, 20.8.14-MMM. Received from other author (Hua Wang) file & signed permission 4.9.14-MMM. -- Full-text (Pub v.) added to Dark upload for ERA2018, 26.3.18--MM. Supporting documentation added to dark upload - HD 13/6/18