Research Reports 2003@Up date@2006.7.10
 
Abstracts of Papers     
  1. Material Processing Using Microorganisms (An Investigation of Microbial Action on Metals), Yasushi KUROSAKI, Masahito MATSUI, Yuichi NAKAMURA, Kenichi MURAI and *Toshio KIMURA: JSME International Journal, Series C, Vol. 46, No. 1, pp. 322-330, 2003.

    The possibilities for developing a new type of material processing using a microbiogenic function are investigated with a microbial corrosion test of metals under the sea water. The behavior of microorganisms in the corrosion of metals (mild steel, copper and aluminum sheets) is examined, and their action on these metals is discussed. As a result, three processing methods (biomachining, biodeposition and biorecycling) are proposed and discussed.

  2. Oxygen Partial Pressure Dependences of a-c Phase Ratio, Crystallinity, Surface Roughness and In-Plane Orientation in YBCO Thin Film Depositions by IBS, T. Endo, K Yoshii, S. Iwasaki, H. Kohmoto, H. Saratani, S. Shiomi, M. Matsui and Y. Kurosaki: Proceedings of IUMRS International Conference on Electronic Materials (Xi'an 2002); Superconductor Science and Technology, Vol. 16, pp.110-119, 2003.
     
    YBa2Cu3OX thin films were grown on MgO by ion beam sputtering at various substrate temperatures TS and oxygen partial pressures PO with a supply of either oxygen molecules or plasma (PL) to study fundamental crystal growth of perovskite oxide. The a-phase growth is enhanced by PL due to two mechanisms, the collision retarded surface migration, and plasma energy assisted atomic rearrangement and surface energy reduction. The mixed film can release a strain energy from interior grain to ambient media, then it has good crystallinity but a rough surface. In contrast, the pure single a-phase film has poor crystallinities but the smoothest surface because the strain energy is stored in the interior. In-plane orientation is improved by increasing the a-phase ratio, and in-plane crystallinity can be improved by PL.

  3. Quantitative Estimation of Fracture Surface for Mild Steel Using Fractal Analysis, Mir Behdad KHAMESEE, Masahito MATSUI, Kenichi MURAI, *Toshihide ISHIHARA and Yasushi KUROSAKI: Proceedings of the IMMM2003, pp.147-152, 2003.

    The use of fractal dimension calculations, for quantitative classification of various objects, is well established in many areas of the physical and life sciences. Such fractal dimension calculations are useful in that they furnish some measure of geometrical complexity that is not available through traditional approaches. In this research fractal analysis was applied for quantitative estimation of fracture surfaces. Fracture surface profiles of mild steel were generated under various kinds of notch root (shape and radius) and tensile speed tests are examined by employing two methods of fractal analysis. A method for quantitative estimation of fracture surface phenomenon caused by fracture accidents is presented, and its validity is confirmed. Although the fractography has used for texture determination of fracture surfaces, it is known that the surface fractography is not enough for quantitative estimation of fracture surface but it is necessary. Even if under the same fracture type, fractal dimension is not constant, but depends on the specimen shape, and thus on the fracture strain. By using fractal dimension and fractography as a method, fracture surface can be estimated.

  4. Micro-Rheometry of Pressurized Lubricants and Micro-Nanorheology, Yuichi NAKAMURA and Yasushi KUROSAKI, Proc. 2003 JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment, pp.69-70, 2003.

    In the present study, micro-rheometry of pressurized lubricants employing a diamond-anvil pressure cell and a laser confocal displacement sensor of 0.4ƒΚm resolution was shown.. High pressure viscosity was obtained up to 2 GPa at 200 Ž for traction oils and PFPE oils. The linearity between logarithmic viscosity and pressure is confirmed. Viscosity-pressure coefficient ƒΏ at room temperature was almost twice larger than that at 100 Ž. ƒΏfor hard disk oil, Zdol2000, was 13 /GPa at 24 Ž ` 5 /GPa at 150 Žand was similar to that of paraffinic mineral oil. The feature of the obtained high pressure volume was different for each oil up to 6 GPa. Zdol2000 was the most compressible of all the sample lubricants and its high pressure refractive index increased about 10 % at 4.8 GPa. Zdol2000 remained  transparent up to 4.8 GPa under isothermal loading. Some considerations for lubricant's micro-nanorheology was also mentioned with high pressure lubricant's rheology.
Abstracts of Books and Reviews
  1. Surface Migration is a Crucial Factor for Growth of a-c Oriented YBCO Thin Films, Tamio ENDO, Hideaki KOHMOTO, Shin-ichi IWASAKI, Masaomi MATSUO, Masahito MATSUI, Yasushi KUROSAKI, Hitoshi NAKANISHI* and Kazuhisa NIWANO*: Proceeding of JSPS-DST (India) Asia Academic Seminar 2001, (Hyderabad), pp. 205-223, 2003.

    In order to clarify mechanisms of a-c orientation growth of YBa2Cu3OX thin films, the films were deposited on MgO by ion beam sputtering employing various deposition parameters. The "surface migration" model is proposed by the results. At lower substrate temperatures (TS), the a-phase growth is dominated. With increasing TS, the c-phase ratio increases due to larger thermal surface migration. The a-phase growth is enhanced by the plasma. The a-phase ratio increases while the c-phase ratio decreases with increasing oxygen partial pressure PO. This can be interpreted by sputtered particles kinetic energy assisted surface migration. The plasma has larger collision cross section, then the particle energy is reduced, resulting in the enhancement of a-phase growth. The proposal of surface migration mechanism can be supported by three additional experiments. The growth of a-phase is enhanced by increases in (1) "film" surface roughness, (2) "substrate" surface roughness based on "polishing" and (3) "substrate" surface roughness due to "plasma exposure". This is because the surface migration is suppressed by larger surface barrier.
  2. 20 Years for the Study of Tribology and Lubricant's Properties under High Pressure (in Japanese), Science Technology and Future, Teijin Shougakukai, Yuichi NAKAMURA, pp. 342-344, 2003.

    This introduced the importance of physical properties of lubricants under high pressure (e.g., density, elastic constant and viscosity) for the tribological evaluation (i.e. friction and wear) of rolling bearings, gears and traction drives. 20 years studies for the application of a diamond-anvil pressure cell (DAC) for tribological measurements were also introduced. As an example, the viscosity measurements of traction oil up to 2 GPa, 200Ž were illustrated with a falling sphere viscometry in the DAC.
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