Under the presidency of the late Professor Shoji Nishikawa, the Crystallographic Society of Japan was founded in 1950 consisting of 102 members to promote crystallography and allied sciences in Japan and to serve as an electorate for the members of National Committee for Crystallography which had been formed in 1949. The development of the Society which has since taken place is closely related to an enormous progress in crystallography itself ; we now have 4 honorary members, 894 regular members, and 34 supporting members. The Journal of the Crystallographic Society of Japan, first published in 1959, now appears bimonthly to review update topics, meeting with ever increasing demand for crystallographic knowledge in our country.

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The birth of the present Society was due to the efforts of S. Nishikawa, T. Ito, S. Miyake, and other forerunners. The sympathy and friendship of P. P. Ewald and R. W. G. Wyckof f toward Japanese crystallographers for the birth should be reflected. The proceedings of the first meeting were reported in a journal “X-Rays” [6, No. 1 (1930), 44] .

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Activities of the research associations and groups relating to crystallographic studies in Japan just before their amalgamation into the new Crystallographic Society of Japan in 1950 are reminisced.

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Modern crystallography is a research field of material sciences which concerns the structure on atomic level. A personal view is presented about where it is located in the history and a map of science and technology. Based on this view, its future is prospected. In conclusion, no matter recognized properly, the modern crystallography will continue to play a significant role in science and technology as if it is air and water in life.

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The molecular and submolecular mechanism of muscle contraction was surveyed from a crystallographic point of view.
The contraction is a result of interactions of two kinds of myofilamants, thick and thin filaments, which are the assemblies of hundreds of myosin and actin molecules, respectively. No conspicuous intramolecular conformational change associated with contraction can be found by X-ray diffraction analysis. What can be detected on contraction is the change in steric relationship between both kinds of filaments. The merits and demerits of electron microscopic and X-ray diffraction techniques in analyzing such changes are discussed. Recent new findings using the technique to reconstruct the three-dimensional structure of such filaments from the electron microscopic images by Fourier transform and synthesis are referred to.

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Certain types of crystal structure are characterized by such symmetry operations as each effective only within a domain in the structure. Due to the geometric relations these local symmetry elements hold with the space-group elements, the macroscopic properties and X-ray diffraction pattern of a crystal of this type frequently exhibit a symmetry higher than its Laue symmetry.

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For the VLSI fabrication, a material design fit for its device and process design is required to silicon wafers of the starting material.
They must be finely controlled about impurities, crystal defects and warpage etc. to conform to the thermal history through the derice fabrication processing.

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Recent progress in the study of the C-S-H gel structure has been briefly reviewed. The TMS method gives useful information on the polycondensation of silicate anions during hydration of cement. Prospect and retrospect of cement chemistry have been remarked in connection with crystallography.

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Gem materials are grouped into five categories: 1) Genuine natural gemstones, 2) imitation gemstones, 3) treated gemstones, 4) synthetic gemstones and 5) artificial gemstones. Diagnostic properties in identif icating and discriminating gem materials of the same species are due to the differences in crystal growth processes and conditions among gemstones of different categories. Crystallography, particularly science of crystal growth, may play important roles in this respect.

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A short description is given on the functional properties of shape memory alloys, being composed of the following five items: Mechanism of the shape memory effect and associated transformation pseudoelastictty. Prerequisites for shape memory alloys and the kinds so far found. Crystal structures of the matrix and various kinds of martensites in shape memory alloys. Two stage pseudoelasticity due to successive martensitic transformations. Applications of the shape memory effect.

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For the solidstate engineers utilizing single crystals for elecronic and opto-electronic devices, an ultimate goal is to design crystal structures with which they could realize properties pertinent to the device performances. Present article summarizes several approaches so far made as mile-stones to the above goal.; The first is an approach via “figure of merit”, and an example is given for the case of acoustooptic medium for the ultrasonic light-beam deflection devices. The second is with “ionic substitution method”, and progresses in rare-earth garnet thin film design for magnetic-bubble memory device are examined. The third approach concerns with the selection of the one among the several structures built with the identical building unit. A brief account is given for “oxygen-octahedral ferroelectric crystals” applicable as electro-optic, nonlinear optic and electro-mechanical devices. The last approach is to have a kind of prescription of the structure. As a successful example, crystal structures of neodimium and alkali-metal-neodimium ultra-phosphates are reviewed.

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Hetero-structures with clean interfaces have been required to obtain low thresholds in semicondutor lasers. Conditions for cl can interfaces of the hetero-structures and their fabrication methods will be described. Today hetero-structures with different bandgaps can be obtained with a variety of semiconductor crystals, which utilize combinations of seeral elements. The concept of the hetero-structure will be expanded not only in opto-electronic but also for electron transport deuices.

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For long years, mechanism of crystal growth has been believed to depend on the screw dislocations. But the growth which depends on the screw dislocation has scarce-ly observed in silicon CVD. Most popular nucleus of crystal growth observed has been complexed screw-like defect located on the edge of stacking fault. There are also so many discrepancies from the standard understandings even about the structures of stacking fault.

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The reactions on crystal surfaces are discussed by using a few examples; the adsorption of hydrogen on Pt (100), the exchange reaction of hydrogen on stepped Pt (111) surfaces, the hydrogenation of 1, 3-butadiene on MgO (111), and the isomerization of 1-butene on the edge surface of MoS₂.

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Solid-state reactions, which have been investigated with particular reference to the crystal structures of reactant and resultant molecules, are briefly reviewed under the headings of topochemical reaction, topochemical and topotactic reaction, and crystal engineering.

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The structures of quenched melts in the system CaO-MgO-SiO₂ have been studied using the Raman spectroscopic technique. Quenched melts along the joins Ca₂SiO₄-SiO₂and Ca MgSiO₄-SiO₂consist principally of three different structural units; with increasing SiO₂ along these joins the structural units change from monomer (SiO₄^4-) +dimer (Si₂ O₇^6-) +chain (SiO₃^2-) through monomer+chain+sheet (Si₂O₅^2-) to chain+sheet + 3-dimentional network (SiO₂) . The ratios of these structural units change little with pressure in the compositional ranges studied. However, the structure of 3-dimentional network appears to change with pressure. The viscosity of melts enriched in the 3-dimentional network decreases with increasing pressure at constant temperature. Particularly NaAlSi₂O₆ (jadeite) melt shows a large decrease in viscosity. Glass quenched from the same melt shows an increase of density, a shift of AlKα radiation, and changes of both infrared absorption and Raman spectra with increasing preassure of quenching. These changes are due to the structural changes of melts probably caused by decrease in size of rings consisting of (Si, Al) O₄tetrahedra. At higher pressures (>50 kbar) Al in the melts may shift from 4-fold to 6-fold coordination, resulting in further decrease in viscosity and increase in density.

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Various types of modulated structures are reconsidered from a unified point of view in which the structures are regarded as the wave-structures which are generated as a result of divergent fluctuation of some entity in prototype structures. K₂SeO₄, CuAu II and TiO_2-X are considered as examples.

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The typical characteristic applications of the synchrotron radiation to crystallography are listed in a table and, some of the most promising fields of research are explained by quoting the works already published and also by suggesting new subjects to be developed.

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Among newly developed X-ray detectors, multiwire proportional chambers are described with reference to the working principles and signal read-out techniques. The variable detection area, moderate position sensitivity and potential high count-rate capa-bility can be exploited in making an efficient data collection system in various diffraction experiments. References are also made to problems encountered in making synchrotron radiation detectors.

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Electron source has recentlymade a remarkable progress with respect to brightness and monochromaticity. Especially the resolution of micro-probe devices such as SEM and STEM has greatly improved by field emission electron beam. In addition, coherent optics (e. g. holography) has just been introduced into the field of electron optics.

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Several structural studies at a pulsed neutron source using the time of flight (TOF) method are reviewed. The TOF method when combined with the use of a position sensitive detector (TOF-PSD) is useful for the measurements both of diffuse scattering and Bragg reflections. It is also a powerful technique for studying time dependent phenomena. The ⁶Li-glass scintillator is introduced as a new neutron detector.

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A brief review is made of the past contributions of computers to crystallography. Discnssion on their anticipated usage which is based on the current trend in the com-puter technology will be given. Applications to solid state studies involving synchrotron radiation will be stressed.

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Recent progress in the crystallographic studies on the title compounds has been reviewed showing how to approach the problems about the structures and functions of the biological molecules and to develop the frontier research in biological science.

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The importance of the X-ray scattering from solution in understanding the structurefunction relationship of some biological systems is emphasized. Especially, moderateangle scatterings, to which not so much attention has been paid so far, were extracted from the solution scatterings, and were clearly shown for several biologically important materials. Structural information was obtained from the radial autocorrelation function about the scatterer, and a method to analyse the structures in such systems is briefly dercribed.

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A method of analyzing an incommensurate structurc based on a multi-dimensional space group is explained by using a simple fictitious example of one-dimensional lattice with one-dimensional displacement and density modulations. The usefulness of the application of this multi-dimensional analysis to real incommensurate and/or commensurate structures is discussed.

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