Research Outline †

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Multi-scale Simulations for Softmatters (MSS) †

See MSS Project.

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Direct Numerical Simulations (DNS) for Colloidal Dispersions †

See KAPSEL Project.

Related Papers:

  • Yasuya Nakayama, Kang Kim and Ryoichi Yamamoto, Simulating (electro) hydrodynamic effects in colloidal dispersions: smoothed profile method Eur. Phys. J. E, 26, 361-368 (2008).
  • Kang Kim, Yasuya Nakayama and Ryoichi Yamamoto Direct Numerical Simulations of Electrophoresis Phys. Rev. Lett., 96, 208302 (2006).
  • K. Kim and R. Yamamoto, Efficient simulations of charged colloidal dispersions: A density functional approach, Macromol. Theory Simul., 14, 278-284 (2005).
  • Y. Nakayama and R. Yamamoto, A Simulation Method to Resolve Hydrodynamic Interactions in Colloidal Dispersions , Phys. Rev. E, 71, 036707 (2005).
  • R. Yamamoto, Y. Nakayama, and K. Kim A Smooth Interface Method for Simulating Colloidal Dispersions, J. Phys.; Condens. Matt. 16, S1945 (2004). [PDF]
  • R. Yamamoto, Simulating particle dispersions in nematic liquid-crystal solvents, Phys. Rev. Lett. 87, 075502 (2001).
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¡¡Dynamics and Rheology of Model Polymer Melts †

Related Papers:

  • R. Yamamoto and A. Onuki, Entanglements in a quiescent and sheared polymer melt, Phys. Rev. E, 70, 041801 (2004).
  • R. Yamamoto and A. Onuki, Dynamics and Rheology of a supercooled polymer melt in shear flow, J. Chem. Phys. 117 2359-2367 (2002).
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Dynamics and Rheology of Glasses and Supercooled Liquids †

Visualization of the dynamical heterogeneity in Glassy Material

  • Displacements of particles (start r[t], end r[t+t*]) are plotted for two temperatures. At a time t*, the non-Gaussian parameter shows a maxmum.
image1.jpg
  • We then apply shear flow at a fixed temperature T=0.26, and plotted the displacement vectors (start r(t), end r(t+t*)-\dot{\gamma}\int_{t}^{t+t*} y(s) e_x ds¡Ë. Average streaming due to shear is subtracted. Dynamical heterogeneity tends to disappear with increasing shear rate (shear effect <-> temperature effect).

Related Papers:

  • K. Miyazaki, D.R. Reichman, and R. Yamamoto Supercooled Liquids under Shear: Theory and Simulation, Phys. Rev E, in print. [cond-mat/0401528]
  • R. Yamamoto and W. Kob, Replica-exchange molecular dynamics simulation for supercooled liquids, Phys. Rev. E 61, 5473-5476 (2000).
  • K. Kim and R. Yamamoto, Apparent finite-size effect in the dynamics of supercooled liquids, Phys. Rev. E 61, R41-R44 (2000).
  • R. Yamamoto and A. Onuki, Heterogeneous Diffusion in Highly Supercooled Liquids, Phys. Rev. Lett. 81, 4915-4018 (1998).
  • R. Yamamoto and A. Onuki, Dynamics of Highly Supercooled Liquids; Heterogeneity, Rheology, and Diffusion, Phys. Rev. E 58, 3515-3529 (1998).
  • R. Yamamoto and A. Onuki, Nonlinear Rheology of a Highly Supercooled Liquid, Europhys. Lett. 40, 61-66 (1997).
  • R. Yamamoto and A. Onuki, Kinetic Heterogeneities in a Highly Supercooled Liquid, J. Phys. Soc. Jpn. 66, 2545-2548 (1997).
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Diffusion Dynamics of Ions in Conductive Glasses †

Related Papers:

  • R. Yamamoto, M. Kano, and Y. Kawamoto, Computer simulation of ionic conduction in ZrF_4-BaF_2 glass, II. Normal mode analysis, J. Phys.: Cond. Matt. 9, 5157-5166 (1997).
  • R. Yamamoto, T. Kobayashi, and Y. Kawamoto, Computer simulation of ionic conduction in ZrF_4-BaF_2 glass, J. Phys.: Cond. Matt. 7, 8557-8567 (1995).
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Molecular Dynamics Simulations of Phese Equilibrium and Phase Transition †

Related Papers:

  • R. Yamamoto and X.C. Zeng, Molecular dynamics study of a phase-separating binary fluid mixture under shear flow, Phys. Rev. E 59, 3223-3230 (1999).
  • R. Yamamoto and K. Nakanishi, Computer simulation of vapor-liquid phase separation in two- and three-dimensional fluids. II. Domain structure, Phys. Rev. B 51, 2715-2722 (1995).
  • R. Yamamoto and K. Nakanishi, Computer simulation of vapor-liquid phase separation in two- and three-dimensional fluids, Growth law of domain size, Phys. Rev. B 49, 14958-14966 (1994).
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Inter-molecular Interactions of CFC Alternatives †

Related Papers:

  • R. Yamamoto, O. Kitao, and K. Nakanishi, Monte Carlo Simulation of Fluoro Propane, Fluid Phase Equilibria 104, 349-361 (1995).
  • R. Yamamoto, S. Matsuo, and Y. Tanaka, Thermal Conductivity of Halogenated Ethanes, HFC-134a, HCFC-123 and HCFC-141b, Int. J. Thermophys. 14, 79-90 (1993).