TANSO
Online ISSN : 1884-5495
Print ISSN : 0371-5345
ISSN-L : 0371-5345
Volume 1976, Issue 87
Displaying 1-4 of 4 articles from this issue
  • Effect of Neutron-Irradiation and Fracture Criterion
    Motokuni ETO, Tatsuo OKU, Katsuo FUJISAKI, Yasuichi SASAKI
    1976 Volume 1976 Issue 87 Pages 123-129
    Published: October 15, 1976
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    Studies were made on the effect of neutron-irradiation on the compressive strength of some graphites for the HTGR. Irradiation temperature and neutron fluence were 200-1100°C and 4×1021 n/cm2 (E>0.18MeV), respectively. Fracture criterion and the statistical properties of the irradiated graphites were also investigated here. The materials used were several imported graphites such as 7477/PT, IM2-24, IM-2, H327 and some domestic ones.
    Increase in strength caused by irradiation was most pronounced in the case of anisotropic petroleum coke graphite, while only small amount of the increase was observed for the fine-grained isotropic graphite. Constant energy criterion, (σ/σ0) 2Y/Y0, was obtained, when both the fluence and irradiation temperature were low. This was also obeyed in the case of high temperature and high fluence for the isotropic graphites. Here, σ0, σ and Y0, Y are the compressive strengths and Young's moduli before and after irradiation, respectively.
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  • S. Marinkovic, P.W. Whang, A. Navarrete, P.L. Walker
    1976 Volume 1976 Issue 87 Pages 130-134
    Published: October 15, 1976
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    Graphite-carbon composites have been fabricated using a natural graphite powder which was molded at low pressures and room temperature and infiltrated by a CVD technique at 700°C using propylene as a source of carbon. The rate of removal of open porosity by carbon infiltration is proportional to open porosity up to an infiltration time of at least 24 hr. Flexural strength, Young's modulus and electrical conductivity of the composites progressively increase with increasing apparent density (d), being approximated by expressions of the type Y=adb over most of the infiltration range. Knoop hardness is increased by infiltration but remains much less than that found for cellulose carbon-CVD composites of comparable infiltration. Infiltration has interesting effects on CTE parallel and perpendicular to the original molding direction and CTE ratios. Heat treatment of infiltrated composites up to 2400°C results in density decreases and some degradation in mechanical properties.
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  • Sugio OTANI, Takumi ENDO, Etsuro OTA, Asao OYA
    1976 Volume 1976 Issue 87 Pages 135-137
    Published: October 15, 1976
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
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  • The Last 25 Years
    S. Mrozowski
    1976 Volume 1976 Issue 87 Pages 138-144
    Published: October 15, 1976
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    Abstract: The history of the development of ideas and of advancements achieved in knowledge of various electronic properties of chars, carbons and graphites is presented. The subject is discussed by considering four periods: the early years, when carbons were not yet recognized as a separate class of solids (pre-1949), the pioneering period, when organized and planned research was begun at various places (1949-56), the start of international cooperation and the consolidation of carbon science (1957-64) and finally the most recent period of detailed studies and advancements on many fronts (1965-74). The main problems awaiting solution are indicated and the importance of carbon studies for the general understanding of the electronic processes in disordered solids is emphasized.
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