| Citation | Distinguished for his wide-ranging investigations of the microstructure of materials using electron microscopy and convergent-beam electron diffraction. His early work on dislocation arrangements in deformed copper crystals stands with that of Basinski as the main pillar on which all recent theories of work hardening are built. His monograph on anisotropic elasticity theory of dislocations is a standard reference. He has led a collaborative effort requiring a very high order of both theoretical and experimental technique to make from image-plane diffraction analysis ('real space crystallography') and convergent-beam diffraction a complete system for crystallographic structure determination in the electron microscope. He is now recognised as the world expert in this powerful technique and has used it for the determination of local crystal structure on the 10nm scale. Significant applications include precipitate structure in steels, new phases in the contact regions of integrated circuits and the correction of important errors in the structure of transition metal dichalcogenides. With the first observation of solitons (discommensurations) in the stripe and triply incommensurate states of these layer compounds, he has produced startling dynamic images of the basic phase transition mechanisms. |