| Project/Area Number |
09650074
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Engineering fundamentals
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KOBAYASHI Ryo Hokkaido Univ., Res. Inst. for Electronic Sci., Asso. Pro., 電子科学研究所, 助教授 (60153657)
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| Co-Investigator(Kenkyū-buntansha) |
TANAGATA Tatsuo Hokkaido Univ., Res. Inst. For Electronic Sci., Inst., 電子科学研究所, 助手 (80242262)
NISHIURA Yasumasa Hokkaido Univ., Res. Inst. For Electronic Sci., Pro., 電子科学研究所, 教授 (00131277)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1997: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | grain boundary / phase field model / recrystallization / singular diffusivity / spiral steps / segregation / granular materials / self-replicating pattern / recrystallization / grain boundarg migration / grain rotation / step dynamics / screw dislocation / spiral step / bunching / phase field model / grain boundary / polycrystal / singular diffusivity / nonlinear semi-group theory / segregation / granular materials / self-replicating / 反応拡散系 / フェーズフィールド / 多結晶 / 相分離 / Cahn-Hilliard / ブロックコポリマー / 散逸系 |
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| Research Abstract |
(a) Usual phase field models have an essential short coming that they cannot describe the formation of poly-crystals since they are lacking in the information of orientation. We proposed a vectorized phase field model which enables us to simulate a simultaneous crystallization of many particles with various orientations and a formation of grain boundaries.
(b) Recrystallization takes place through the two basic processes, say, (I) grain boundary migration and (ii) grain rotation. Almost all the model of recrystallization handle the process (I) only. We proposed a totally new phase field model which can treat both of the processes (I) and (il) simultaneously.
c In the above recrystallization model the equation for the evolution of angle variable expresses a non-local interaction by introducing a new mathematical concept "singular diffusivity" We justified this new equation and analyzed it mathematically.
(d) It is well known that the mixture of granular materials can segregate in the rotating cylinder. We investigated this phenomena through experiments and modeling and found that it is caused by the property of strong segregation in the suface flow of binary mixture of granular materials.
(e) A mathematical model of step dynamics on the facet of growing crystals are presented. This model is able to describe the motion of steps caused by the arbitrary number of screw dislocations.
(f) Mathematical structure which produces self-replicating patterns were made clear by the approach of experimental mathematics. We demonstrated that the ordered saddle node bifurcation branches and the paths connecting them are essential for the formation of self-replicating patterns.
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