We study the ordering kinetics of an assembly active Brownian particles (ABPs) on a two-dimensional substrate. use coarse-grained equation for composition order parameter ?(r,t),wherer and t denote space time, respectively. The model is similar to Cahn-Hilliard orModel B (MB) conserved with additional activity term strength ?. This has been introduced by Wittkowski et al., Nature Comm. 5, 4351 ...