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1998 Fiscal Year Final Research Report Summary

Nonlinear dynamics in fractal structures

Research Project

Project/Area Number 09044048
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionJoint Research
Research Field 物性一般(含基礎論)
Research InstitutionHokkaido University

Principal Investigator

NAKAYAMA Tsuneyoshi  Hokkaido University, Grad.School of Eng., Professor, 大学院・工学研究科, 教授 (80002236)

Co-Investigator(Kenkyū-buntansha) JAGANATHAN Anu  Universite de Paris-Sud, Laboratory of Solid State Physics, Research Associate, 固体物理学研究所, 博士研究員
KAPLYANSKII アレクサンダー  ロシア科学アカデミー, ヨッフェ物理工学研究所, 教授
DIJKHUIS Jaap  University of Utrecht, Debye Institute, Professor, デバイ研究所, 教授
TIAN D.C.  University of Wuhan, Department of Physics, Professor, 物理学科, 教授
ORBACH Raymond  University of California, Riverside, Chancellor, リバーサイド校, 学長
KAPLYANSKII Alexander A.  Academy of Science of Russia, A.F.loffe Physico-Technical Institute, Professor
Project Period (FY) 1997 – 1998
Keywordsglass / boson peak / hopping conduction / heat transport / localized mode / nonlinear conduction
Research Abstract

The purpose of this project is to clarify various unique phenomena observed in network glasses, polymers, gel-aggragates taking fractal structures, in particular about the hopping conductivities due to anharmonic interaction between strongly localized modes observed at low temperatures. Glasses are different in several aspects from usual random media without internal strain and are not in thermal equilibrium. Thermal conductivities kappa(T) observed in polymers, network-forming glasses, and gelaggragates show universal behaviors such as the T^2-dependence below a few Kelvin and the plateau at around 10K.We have clarified that the plateau in kappa(T) can be explained by the existence of a mobility edge for phonons in glasses. At the high-temperature end of the plateau at around 10-30K, kappa(T) observed rise with increasing temperature T.We have shown quantitatively that the rise of kappa(T) certainly at least initially linear on I can be explained the hopping mechanism, namely, we have … More suggested the existence of an additional heat conduction channel, which can be explained by incorporating generic features of vibrational states in glasses at relevant temperatures. In addition, we have clarified in this project that the boson peak in the vicinity of 3O-50cm^<-1> observed in Raman and neutron scattering experiments for network-forming glasses has the same origin as the plateau region in thermal conductivities, In the second, we have pointed out that locally distorted potentials with large anharmonicities play a role in creating strongly localized modes in the acoustic band. Finally, we have succeeded to quantitatively explain that the large anharmonicity is the cause of the hopping transport of strongly localized modes, which leads a consistent explanation of the plateau and the subsequent monotonic increase of k above the plateau temperature. Our analysis will shed new light on the elucidation of long-standing problem on various unique and universal properties observed in fractal structures and glasses. Less

  • Research Products

    (22 results)

All Other

All Publications (22 results)

  • [Publications] Takamichi Terao: "Vibrational dynamics of cluster-cluster aggregations" Physical Review B. 57(4). 4426-4430 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsuneyoshi Nakayama: "The origin of the Boson peak in network-forming glasses" J.Physics : Condensed Matter. 10(1). L41-L47 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsuneyoshi Nakayama: "Low-energy excitations in water : A simple-mode analysis" Physical Review Letters. 80(6). 1244-1247 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Shima: "Fineite-time scaling for the 3d Anderson transition" J.Phys.Soc.Japan. 67(7). 2189-2192 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsuneyoshi Nakayama: "Computing the Kubo formula for large systems" Physical Review E. 58(3). 3984-3992 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takamichi Terao: "Sol-gel transition of reversible cluster-cluster aggregations" Physical Review E. 58(3). 3490-3494 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsuneyoshi Nakayama: "Strongly localized modes as the origin of the Bose peak in glasses" Physica B. in press. (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takamichi Terao: "Vibrational characteristics of cluster-cluster aggregations" Physica B. in press. (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsuneyoshi Nakayama: "On the increase in thermal conductivities above the plateau region in galsses" Physica B. in press. (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takamichi Terao: "Numerical study on light-scattering for cluster-cluster aggregations" Physical Review E. in press. (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Yamaguchi: "Effects of high pressure on the Bose peak in a-GeS2 studied by light scattering" Physica B. in press. (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Terao and T.Nakayama: "Vibrational dynamics of cluster-cluster aggregations" Physical Review B. 57. 4426 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakayama and N.Sato: "The origin of the Boson in Network-forming glasses" J.Physics : Condensed Matter. 10. L41 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakayama: "Low-energy excitations in water : A simple-mode analysis" Physical Review Letters. 80. 1244 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Shima and T.Nakayama: "Finite-time scaling for the 3d Anderson transition" J.Phys.Soc.Jpn.67. 2189 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakayama and H.Shima: "Computing the Kubo formula for large systems" Physical Review E. 58. 3984 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Terao and T.Nakayama: "Sol-gel transition of reversible cluster-cluster aggregations" Physical Review E. 58. 3490 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Yamaguchi, T.Nakayama and T.Yagi: "Effects of high pressure on the Bose peak in a-GeS2 studied by light scattering" Physica B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakayama: "Strongly localized modes as the Bose peak in glasses" Physica B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Terao and T.Nakayama: "Vibrational characteristics of cluster-cluster aggregations" Physica B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakayama and R.Orbach: "On the increase in thermal conductivities above the plateau region in glasses" Physica B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Terao and T.Nakayama: "Numerical study on light-scattering for cluster-cluster aggregations" Phys.Rev.E. (in press).

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-12-08  

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