Journal of the Japan Society for Abrasive Technology
Online ISSN : 1880-7534
Print ISSN : 0914-2703
ISSN-L : 0914-2703
Volume 51, Issue 12
DEC.
Displaying 1-3 of 3 articles from this issue
  • Masahiro OOKA, Hideki SASAOKA, Kazuhito NISHIMURA
    2007 Volume 51 Issue 12 Pages 725-728
    Published: December 01, 2007
    Released on J-STAGE: May 18, 2009
    JOURNAL FREE ACCESS
    Nano-diamond (ND) films with a grain size of 5-10 nm are regarded as a promising electrode material for electron emitters because the threshold electric fields required to obtain an emission current density of 1 mA/cm2 have been reported to be less than 1 V/μm. Here, we developed a testing device of a soft x-ray generator utilizing an ND film as an electron emitter and evaluated its performance by measuring the ion quantity generated by the soft x-rays. The ion generation power of the device with an ND film was about 10 times higher than that of a conventional device with a hot filament when operated with the same power of 6 W. The experimental results confirmed the validity of usage of ND films as electron emitters for high-power and energy-saving soft x-ray generators.
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  • Effects of dynamic pressure caused by coolant on grinding accuracy
    Heisaburo NAKAGAWA, Keiji OGAWA, Youhei ODA, Toshio KIMURA
    2007 Volume 51 Issue 12 Pages 729-734
    Published: December 01, 2007
    Released on J-STAGE: May 18, 2009
    JOURNAL FREE ACCESS
    This paper describes high accuracy contour grinding. Variation of normal grinding force affects the grinding accuracy in contour grinding using a machining center because of low grinding wheel stiffness. Therefore, it is necessary to decrease the variation of the normal grinding force. However, the influence of the normal force variation caused by dynamic pressure with coolant flow has not been considered. Therefore, the normal grinding force variation was estimated by a simple model applying a dynamic pressure distribution in a journal bearing. Moreover, experiments were performed to investigate the influences of grinding conditions on the dynamic pressure. The results of a verification experiment indicated that the variation of the normal grinding force could be reduced by considering the influence of the dynamic pressure caused by coolant and higher accuracy contour grinding could be achieved.
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  • Yoshihito TAKAMI, Yukihiro SAKAMOTO, Matsufumi TAKAYA
    2007 Volume 51 Issue 12 Pages 735-740
    Published: December 01, 2007
    Released on J-STAGE: May 18, 2009
    JOURNAL FREE ACCESS
    Synthesis of diamond using mode-translation type microwave plasma CVD from a CH4-H2-O2 reaction gas system was investigated. Diamond could not be synthesized by addition of O2 at low CH4 flow rate. On the other hand, diamond could be synthesized by addition of small amounts of O2 at high CH4 flow rate. The area of film formation was extended by addition of O2 at high CH4 flow rate. Moreover, the quality of diamond produced using the CH4-H2-O2 reaction gas system was almost the same as that obtained using the CH4-H2 reaction gas system and the diamond deposition rate was increased by addition of small amounts of O2 at high CH4 flow rate. In conclusion, the deposition rate and quality of diamond were improved by addition of small amounts of O2 at high CH4flow rate in this system.
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