日本結晶学会誌
Online ISSN : 1884-5576
Print ISSN : 0369-4585
ISSN-L : 0369-4585
55 巻 , 3 号
選択された号の論文の13件中1~13を表示しています
総合報告
  • 坂田 修身
    2013 年 55 巻 3 号 p. 171-179
    発行日: 2013/06/30
    公開日: 2013/07/02
    ジャーナル フリー
    The grazing-angle X-ray standing wave(GAXSW)method for model-independent and atomic-scale determination of in-plane structures and X-ray reciprocal-space mapping(XRSM)at a sample angular position for quick structural estimation are discussed. The both have been developed for analysis of a nanoscale structure such as an adsorbed surface system and a buried nanoscale structure. They are synchrotron-based X-ray diffraction techniques, which use monochromatic parallel hard X-rays incident at a small angle close to the critical angle for total-external reflection. GAXSW's are dynamically formed by the interference of an incident, a specularly reflected, and a specularly diffracted beam above a sample surface. A Bragg condition is satisfied on lattice planes perpendicular to the surface. The author describes in-plane structural analyses of a surface system and a thin film. Outcomes of XRSM are briefly summarized for nanoscale structures of a surface, buried interfaces, and a thin film. In particular, results of nanoscale wires are mentioned.
  • 片岡 邦光
    2013 年 55 巻 3 号 p. 180-187
    発行日: 2013/06/30
    公開日: 2013/07/02
    ジャーナル フリー
    Single crystals of Li4+xTi5O12 were prepared by means of electrochemical Li-ion intercalation technique using parent Li4Ti5O12 single crystals. The obtained Li4+xTi5O12(x=1.35)crystallizes in the cubic spinel-related type structre, space group Fd3m, and lattice parameters of a=8.346(3)Å and V=581.3(5)Å3. The Li-ion intercalated sites were successfully determined by single crystal X-ray diffraction. From the result, because of the structural restriction of the spinel structure, unfortunately, the theoretical capacity was revealed to be 175 mAh/g. New material Li2Ti6O13 with rectangular tunnels was synthesized by Na+/Li+ ion-exchange method as one of the negative electrode material having a high capacity than Li4Ti5O12. The Li2Ti6O13 as determined the precise crystal structure by powder neutron diffraction and evaluated reversible Li insertion/extraction reaction.
  • 岩田 忠久
    2013 年 55 巻 3 号 p. 188-196
    発行日: 2013/06/30
    公開日: 2013/07/02
    ジャーナル フリー
    Poly([R]-3-hydroxybutyrate)(P(3HB))and its copolymers are accumulated by a wide variety of microorganisms as intracellular carbon and energy materials, and are extensively studied as biodegradable and biocompatible thermoplastics. Recently, we succeeded in obtaining strong fibers and films by new drawing techniques from microbial polyesters produced by both wild-type and recombinant bacteria. The improvement of mechanical properties of fibers and films is due not only to the orientation of molecular chains but also to the generation of a planar zigzag conformation. The structure of strong fiber with tensile strength of over 1.0 GPa was analyzed by micro-beam X-ray diffraction and X-ray micro-tomography with synchrotron radiation. The strong fibers and films were completely degraded in environment or by extracellular PHB depolymerases. In this article, I present the processing, mechanical properties, highly ordered structure and biodegradability of strong fibers and films produced from microbial polyesters.
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