1. We of an edge dislocation Model: see fiqure consider an area element x-x+dx which displaced from b’→b+db then M We=S x,( x)db IGb 1 dxd b 2(1-y)x Glb--In(R)=aGb? +dx 4m(1-y)1. We of an edge dislocation. Model: see figure. consider an area element x→x+dx which displaced from b'→ b'+db'. then Gb l r Glb R x b x lGb W l x b R r e xy 2 2 b 0 ln( ) 4 (1 ) d d 1 2 (1 ) ( d )d o       = − =  −  = =     