Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Li, L.*; 宮本 吾郎*; Zhang, Y.*; Li, M.*; 諸岡 聡; 及川 勝成*; 友田 陽*; 古原 忠*
Journal of Materials Science & Technology, 184, p.221 - 234, 2024/06
被引用回数：0 パーセンタイル：0(Materials Science, Multidisciplinary)Dynamic transformation (DT) of austenite (
) to ferrite (
) in the hot deformation of various carbon steels was widely investigated. However, the nature of DT remains unclear due to the lack of quantitative analysis of stress partitioning between two phases and the uncertainty of local distribution of substitutional elements at the interface in multi-component carbon steels used in the previous studies. Therefore, in the present study, a binary Fe-Ni alloy with + duplex microstructure in equilibrium was prepared and isothermally compressed in + two-phase region to achieve quantitative analysis of microstructure evolution, stress partitioning and thermodynamics during DT. to DT during isothermal compression and to reverse transformation on isothermal annealing under unloaded condition after deformation were accompanied by Ni partitioning. The lattice strains during thermomechanical processing were obtained via in-situ neutron diffraction measurement, based on which the stress partitioning behavior between and was discussed by using the generalized Hooke's law. A thermodynamic framework for the isothermal deformation in solids was established based on the basic laws of thermodynamics, and it was shown that the total Helmholtz free energy change in the deformable material during the isothermal process should be smaller than the work done to the deformable material. Under the present thermodynamic framework, the microstructure evolution in the isothermal compression of Fe-14Ni alloy was well explained by considering the changes in chemical free energy, plastic and elastic energies and the work done to the material. In addition, the stabilization of the soft phase in Fe-14Ni alloy by deformation was rationalized since the to transformation decreased the total Helmholtz free energy by decreasing the elastic and dislocation energies.
phase to 
phase in zirconium alloy revealed by in-situ neutron diffraction during high temperature deformationGuo, B.*; Mao, W.; Chong, Y.*; 柴田 曉伸*; Harjo, S.; Gong, W.; Chen, H.*; Jonas, J. J.*; 辻 伸泰*
Acta Materialia, 242, p.118427_1 - 118427_11, 2023/01
被引用回数：7 パーセンタイル：61.61(Materials Science, Multidisciplinary)Dynamic transformation from alpha (HCP) to beta (BCC) phase in a zirconium alloy was revealed by the use of in-situ neutron diffraction during hot compression. The dynamic transformation was unexpectedly detected during isothermal compression at temperatures of 900
C and 950C (alpha + beta two-phase region) and strain rates of 0.01 s
and 0.001 s, even though equilibrium two-phase states were achieved prior to the hot compression. Dynamic transformation was accompanied by diffusion of Sn from beta to alpha phase, which resulted in changes of lattice parameters and a characteristic microstructure of alpha grains. The details of dynamic transformation are discussed using the evolution of lattice constants.
池田 隆司; 寺倉 清之*
Journal of Chemical Physics, 119(13), p.6784 - 6788, 2003/10
被引用回数：26 パーセンタイル：63.62(Chemistry, Physical)室温・高圧下におけるメタンハイドレートの構造,ダイナミクス及び電子状態を第一原理定圧分子動力学法を用いて調べた。I型クラスレートのかご構造は4.5GPaで壊れた。かご構造が消失した後、MH-III構造に特徴的な2つの構造が現れた。また、われわれの得たMH-III構造ではCD伸縮振動モードが一つ存在し、加圧とともにブルーシフトを示す。これらはLovedayらが提案したフィルドアイスの存在を支持する結果である。
岸本 泰明; 徳田 伸二; 坂本 慶司
Physics of Plasmas, 2(4), p.1316 - 1325, 1995/04
被引用回数：5 パーセンタイル：28.32(Physics, Fluids & Plasmas)長いウィグラーを持つプラズマ加熱用の高パワー自由電子レーザー(FEL)においては、電子ビームが発散するのを防ぐため収束磁場が必要である。しかしそのような付加的な収束磁場によって引き起こされる長いスケールの横方向の運動はビームの縦方向の運動に変調を与えて、たとえビームがうまく伝播したとしてもビーム粒子と輻射場の間の位相関係を壊し発振が阻害されることがある。本論文ではそのような複雑な磁場構造配位での微妙な位相関係を調べるため、CaryとLittlejohn[Annals of Physics 151,1-34(1983)]によって開発された非正準座標とリー変換を用いた系統的な摂動論を提案する。ここではこの手法を放物状に湾曲した磁極面を持つ自己収束型ウィグラーに適用する。この非正準的なアプローチはこの種の問題に対して見通しが良く包括的な手法であり、また複雑な他の任意のウィグラーに対しても適用することが可能である。
