Basic theory of high-resolution electron microscopy is described in view point of lattice images and structure images of crystalline samples. Image formation process, factors determining the resolution, contrast transfer functions, dynamical diffraction effect and relativistic effect are explained in detail.
Bacterial flagellum consists of a rotary motor and a helical filament as a screw, and works for bacterial motility and taxis. The filament is built by a self-assembly process and has a polymorphic ability to be various forms of supercoils. Here, we describe a complementary use of X-ray diffraction and electron cryomicroscopy for structure analysis of this large helical complex. The structure reveals the molecular mechanism of self assembly and polymorphism.
Energy-filtering transmission electron microscopy (EFTEM) is widely used to make images and diffraction patterns more quantitative by removing the inelastic background, and to perform elemental and chemical mapping at high spatial resolution.The principal factors restricting the spatial resolution in elemental maps are discussed. The relativistic effect on inelastic scattering cross-section, which becomes significant for high-voltage EFTEM analysis, is also discussed in relation to the detection efficiency of core-loss signals.
Element partitioning between minerals and silicate melt has been investigated at pressures 1-17 GPa, by using 6-8 type multi anvil high pressure apparatus. The observed partition coefficients, D, were plotted on partition coefficient - ionic radius (PC-IR) diagram. In the case of olivine/silicate-melt system, partition coefficient of most of the elements gradually decreased with increasing pressure. However, partition coefficient of Al increased with increase in pressure, and this result may be suggesting that partition coefficient of Al may depend on the composition and structure of the coexisting silicate melt. It was difficult to identify peaks of partition coefficient profile in majorite / silicate-melt system. There was a bottom of the partition coefficient profile of Ca-perovskite / silicate-liquid at around 70-80 pm, and the existence of peaks at around 50 and 100 pm is expected from the observed profile of partition coefficient.