“…The 'quality' of the lattice-fringe images also suffered from preferential milling of the boundary regions, which further complicates the interpretation. This preferential thinning is a common problem in HREM image interpretation and has recently been discussed by Kouh, Carter, Morrissey, Angelini and Bentley (1986) and by Simpson, Carter, Sklad and Bentley (1986). The present analysis will therefore be restricted to the determination of the Burgers vectors of secondary dislocations which are identified by the fact that they cause irregularities in the spacing of the primary dislocations.…”