研究員

国立研究法人 海洋研究開発機構

数理科学・先端技術研究分野

〒236-0001 神奈川県横浜市金沢区昭和町 3173-25

*mikiy@jamstec.go.jp*

Every day, every night, I wander around this enigmatic world without any understanding, knoledge, and intelligence. We have mathematics, technology, and other scientific instruments, ... and, however, we do not understand even a part of this world. This implies that those proud intruments are too poor to capture all what we want and what we need. I have once despaired this regrettable fact and have wandered from that time. Now, I use those instruments to understand what is this world, because I saw that those are better among various poor instruments. My major background is in nonlinear-nonequilibrium physics and complicated systems. I also studied biological and soft matter physics, and sociological physics after I obtained Ph.D.

2003年4月〜2006年3月 | （財）日本学術振興会 特別研究員 |

2006年4月〜2008年3月 | （独）東京大学大学院生産技術研究所 ERATO研究員 |

2008年4月〜2009年7月 | 東京大学大学院理学系研究科 研究員 |

2011年7月〜2014年3月 | 海洋研究開発機構 特任研究員 |

2014年4月〜現在 | 海洋研究開発機構 研究員 |

2003年 | 東京大学大学院総合文化研究科 広域科学専攻 博士(後期)課程単位取得退学 |

- Geographycal pattern formation of descrete elements
- Various patterns are known to spontaneously appear in granular materials in nature. One experimental example of them is a pattern appearing in granular layers when the ground bed is vibrated beyond the critical acceleration. When the thickness of these granular layers is greater than a certain value, granular heaps are spontaneously formed via convective flows and becomes round. This rounding process should be important in the large-scale nonequilibrium pattern construction of granular structures such as dunes. The essence of this rounding process is partly explained by the geometric constitutive law of collapse which we found; We reported on a universal pattern observed in the collapse dynamics of a sand heap. Collapse dynamics of a three-dimensional sand heap were studied through experiments and numerical simulations. A phenomenological law that describes the shape of a collapsed sand heap was found, we call this the geometric constitutive law of friction. The law is summarized as the linear relation between the frictional coefficient and the local horizontal curvature. The geometric effect is analogous to the Gibbs.Thomson effect, which is an origin of pattern formation in crystal growth.

Experiments for the stability of the sand heap constructed on a shaped board bonded on a wide acrylic board whose hight is controlled by a motor-driven lift.

- Motion of a soft element
- Most eukaryotic amoeboid cells show centroid movement accompanied with large morphological deformation. The velocity distribution of amoeboid cell has been investigated in detail, and found to be non-Gaussian. Even L´evy walk type search has been considered as the optimal strategy of searching; Takagi et al. suggested that the velocity distribution of Dicty cell has power-law tails. However, although a heuristic fitting model was used, any credible mechanism for creating a L´evy walk has not been proposed. Thus, we proposed the theory of random walks of active deformable particles (ADP) that can move by actively deforming their shape from a sphere. It is well-known that intracellular cytoskeleton makes cell membrane deform dynamically, and, moreover, the shape of an amoeboid cell strongly dominates the dynamics of the cell. Thus, our model can present a possible mechanism for amoeboid cell to create a L´evy walk through the coupling between deformation and centroid motion.

Illustrations of two types of model of active deformable particle.

- Geometric effect of angle of repose revisited, Miki Y. Matsuo, Daisuke Nishiura, Hide Sakaguchi, Granular Matter (2014) 16:441-447 DOI 10.1007/s10035-014-0489-1.
- Large fluctuation and Levy movement of an active deformable particle Miki Y. Matsuo, Hirokazu Tanimoto and Masaki Sano Europhysics Letters 102, 40012, (2013).
- Experimental Study on the characteristics of VIV and Whirl Motion of Rotating Dill Pipe Tomoya Inouse, Chang-Kyu Rheem, Masanori Kyo, Hide Sakaguchi and Miki Yamamoto Proceedings in International Conference on Ocean, Offshore and Arctic Engineering (OMAE), (2012).
- Reflection-Antisymmetric Spatiotemporal Chaos under Field-Translational Invariance Miki Y. Matsuo and Masaki Sano Physical Review E85, 036215 (2012).
- Geometrical model of a self-propelled broken interface M. Y. Matsuo and S. Sano, Journal of Physics A: Math. Theor. 44, 285101, 1-6 (2011).
- Hierarchical mechanism of development of wealth and structure for a premodern local society Miki Y. Matsuo, Physical Review E 83, 066110, 1-8 (2011).
- Dynamics of a deformable self-propelled domain T. Hiraiwa, M. Y. Matsuo, T. Ohkuma, T. Ohta, and M. Sano, Europhysics Letters, Vol. 91, 20001, 1-6 (2010).
- Ordered Patterns of Cell Shape and Orientational Correlation during Spontaneous Cell Migration Y. T. Maeda, J. Inose, M.Y. Matsuo, S. Iwaya, and M. Sano, PLoS ONE 3 (11), e3734, 1-14 (2008).
- Relation between Adaptation and Irreversible Circulation in Bacteria Chemotaxis M.Matsuo, K. Fujimoto and T. Shibata, Progress of Theoretical Physics Supplement 161, 251-254 (2006).
- Violation of Fluctuation-Dissipation Relation in Fragile Glasses Miki Matsuo, Journal of the Physical Society of Japan 74 , 2128-2132 (2005).

- Series in Soft Condensed Matter Vol.4, Non-equilibrium Soft Matter Physics (Invited book chapter), Chapter7 "Dynamics of Deformable Self-Propelled Particles: Relation with Cell Migration", Masaki Sano, Miki Y. Matsuo, and Takao Ohta, World Scientific, pp.365 - 415 ( 2012).