The finite-structure constant ? A contribution of semiconductor physics to the determination of ?.- Surface waves.- High resolution electron energy loss spectroscopy on semiconductor surfaces.- Ternary semiconductors.- Structure and electronic states in a-Si:H.- Chemical trends of deep impurity levels in covalent semiconductors.- Self-interstitials and vacancies in elemental semiconductors between absolute zero and the temperature of melting.- Electronic structure of impurities in transition metals.- Intercalated graphite - A synthetic metal I. Introduction and electronic structure.- Intercalated graphite: A synthetic metal II. Theory of bond length change and conductivity.- Dynamics of fast ion conductors.- Thermoelectric effects in superconductors.- Aspects of nonlinear spectroscopy.- Magnetic components for microwaves and optics.- Applications of the josephson-technology.