Small-angle scattering (SAS) is a very powerful tool to examine heterogeneous microstructures that often appears in metallic materials. In the present chapter, several examples are given to show how the readers can make use of SAS techniques in the research of phase transformation and microstructural assessment in metallic alloys.
We made a cylindrical hole in a Si (110) wafer, and curried out first in-situ observations of the inner surfaces of it to study various high index surfaces and vicinal surfaces simultaneously in the UHV condition by REM-RHEED method. Our studies revealed seventeen surfaces to show well-defined RHEED patterns in the  zone. So-called hill and valley structures were formed on six regions. We attempted to observe the equilibrium shape of the Si vicinal surfaces. Step properties of the (111) and the (110) surfaces were estimated from the analysis of the equilibrium shapes of the vicinal surfaces. Also we determined the roughening phase transition temperatures on the various high index surfaces.
Oxides of the group RMn2O5 (R=a rare earth or Y) are simultaneously ferroelectric and antiferromagnetic at low temperatures. The specific features of the phase transitions in this oxide are reviewed with a particular emphasis on the possible interactions between dielectric and magnetic properties.
The three-dimensional structure of holo S100B from bovine brain has been determined at 2.0 Å resolution by X-ray diffraction. The dimeric S100B molecule is formed by non-covalent interactions between large hydrophobic surface on both S100β subunits. There are two EF-hand motifs per S100β subunit, each of which binds one calcium ion. We observe, in the calcium-bound structure, dramatic changes in the conformation of the terminal helices, from the compact structure in the apo form to a more extended form upon binding calcium. This conformational change suggests a novel mode of target recognition of S100B.
A new diffraction method for the determination of the phase of Bragg reflections is described. Diffracted intensity is recorded while changing continually the wavelength of radiation over a range in the vicinity of the absorption edge of an atom contained in a crystal. The intensity gradient with respect to the wavelength of the hkl reflection is shown to be in a simple relation to the real and imaginary parts of F (hkl) . The phase can be determined by solving two simultaneous linear equations with the intensity gradients measured at two wavelengths as input parameters. The situation is particularly simple when the crystal is centrosymmetric. The method presented here is free from the problem of intensity scaling encountered in other methods of phase determination.
High-quality Bi2Sr2CaCu2O8+δ single crystals have been grown by a traveling solvent floating zone method with a necking technique. The full-width at half maximum of the rocking curves by a X-ray diffraction was improved from 120 arcsec to 70 arcsec by the necking technique. Especially, this technique is very effective on the growth of the single crystals substituted by lanthnoid elements.
ANYBLK is a program for the refinements of the structural parameters in the singlecrystal X-ray analyses. The program is controlled by a text file, containing instructions that can be easily understood. By using the instruction file, various conditions can be imposed on the refinements. The program has a powerful ability in treating rigid bodies: an atom can belong to more than one rigid group. Other related programs that can be used with ANYBLK are also described.