The author and his colleagues have established a new frontier of protein crystallography by developing a novel screenless Weissenberg camera using SR-X-rays at the PF. Luckily, just the first prototype of the camera was being developed, an imaging plate (IP) was also being developed coincidentally for medical use. We combined the camera with IPs and SR-X-rays and established a new data collection system at the PE. This led us to take the initiative of opening this camera system to the worldwide user community of protein crystallographers. Recently, an automated data collection system with fully cylindrical IP-cassettes named Galaxy has been completed based on a totally new idea. Finally time-resolved protein crystallography with monochromatic X-rays and the advanced Galaxy system is discussed.
Synchrotron X-ray diffraction and scattering techniques were applied for the determination of the valence state and the detection of charge ordering in transition-metal oxides. This article includes the following topics of difference Fourier syntheses, X-ray anomalous scattering, the extraction of K-shell electrons, Fourier integration, valence-difference contrast, X-ray magnetic circular dichroism and resonant X-ray magnetic scattering.
A novel density modification method has been applied to phase reconstruction of X-ray single crystal data of quasicrystals. This is based on the low density elimination (LDE) method that is an ab initio structure determination method for crystals in the real space. The location, size andshape of the occupation domains of quasicrystals in the n-dimensional (nD) unit cell are obtained without a prioi model structure. Therefore, the LDE method can be a substitute for the direct method for quasicrystals that are described as nD crystals. The structure solution can easily be found in the trial sets (normally 100 sets) and is confirmed by the subsequent analysis. The result is used as a starting model for constructing a detailed structure model of quasicrystals. The solution of several qusicrystalline structures including a model quasicrystal structure are exemplified.
We have designed and fabricated a new furnace for high-temperature neutron-diffraction measurements. The furnace does not yield any extra peaks due to heaters and refractory, thus we were able to measure very small neutron signals from the sample. Quality neutron diffraction data at high temperatures up to about 1590 °C were analyzed by Rietveld method for various materials as zirconia and calcium titanate.
Charge- and orbital-ordered structures, induced in Pr1-xCaxMnO3 (x=3/8), are examined by low-temperature transmission electron microscopy. New type of orbital-ordered structure, containing additional Mn3+ with eg orbital along the c-direction, was proposed on the basis of the d3x2-r2/d3y2-r2 type of charge/orbital-ordered structure for x= 1/2.