Atomic-scale structure of the interface between graphene and SiC(0001) has been investigated using high-resolution transmission electron microscope observation. Our analysis revealed the presence of two types of the interface structure ; one is formed by decomposition of three SiC bilayers, and the other is formed by that of one SiC bilayer. Formation process of graphene layers on SiC is also described.
Pressure-induced structural transition of rare-earth metal hydride, YH3, has been investigated by synchrotron radiation X-ray diffraction experiments. We observed the pressure-induced structural transformation from the hexagonal metal lattice into an fcc one through an intermediate state, which appears in the wide pressure span of 12∼22 GPa. The obtained X-ray diffraction patterns in the intermediate state are represented by long-period structures, e.g. 27R, of the yttrium metal lattice. These long-period structures are interpreted in terms of the periodic arrangements of hexagonal-type and fcc-type stacking layers of the yttrium metals. Such structural transition is considered to be characteristic for rare-earth metal hydride.
Gap junctions, which consist of arrays of intercellular channels, permit the exchange of ions and small molecules between adjacent cells. Here, we describe the structural determination of a gap junction channel composed of connexin 26 at 3.5 Å resolution. During each step of the purification process, the protein was examined using electron microscopy and/or dynamic light scattering. Dehydration of the crystals improved the resolution limits. Phase refinement using multi-crystal averaging in conjunction with non-crystallographic symmetry averaging resulted in an electron density map for model building. The amino-acid sequence of a protomer structure was assigned to the electron density map.