Continuum and atomistic scale computational mechanics for structures with small length scales. With on-demand call to molecular dynamics simulations and scale up to continuum level constitute models, where predictions can be made for laboratory accessible time and length scales.

Material systems including: crystal plasticity in singly/poly crystalline metals, interfacial/grain-boundary mechanics in nanostructured materials, amorphous solids, nanowires, soft materials.

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二维材料中声子热性质

  国际物理学界权威期刊《现代物理评论》于20181113日发表了由上海交通大学顾骁坤教授,中科院力学研究所魏宇杰研究员,以及科罗拉多大学博尔德分校尹晓波教授、李保文教授以及杨荣贵教授联合撰写的关于《二维材料中声子热性质》的综述性论文: “Colloquium: Phononic thermal properties of two-dimensional materialsReviews of Modern Physics, 90, 041002 (2018)”,魏宇杰、李保文、杨荣贵为共同通讯作者。

  热导率是材料的一项基本物性,表征了材料的热传导能力。对于具有宏观尺度的物体,其中的导热现象可以通过傅里叶导热定律来唯象地描述。随着固体材料尺度的减小,其导热特性表现出与对应的宏观体系不同的规律。《二维材料中声子热学性质》这篇论文主要讨论了二维材料这一类新型材料中声子(晶格振动)这一热载子的输运现象。通过细致分析二维材料中声子性质(如声子色散关系、声子散射率等),讨论了二维系统中傅里叶导热定律是否成立这一基本物理问题。基于多种物理图像,全面阐述了尺度(包括样品长度、纳米带宽度、层状材料的厚度)、应变、缺陷、基底接触等多种因素对二维材料声子热输运及声子热导率的影响;同时也探讨了采用化学方法调控二维材料热学特性的可能性。该论文有助于相关科研人员全面了解二维材料中声子热性质的当前研究进展,并对后续重大研究问题作了深入探讨和展望,对构筑具有优异性能的热--电等多场耦合的低维功能材料具有重要指导意义。 

  该文章的合作者魏宇杰研究员致谢中国国家自然科学基金委(资助号:11425211)以及中国科学院先导B类项目“复杂介质系统前沿与交叉力学”的资助(资助号:XDB22020200)。

  图中列举12种典型二维材料的的热导系数,其中的插入图片为几种典型二维材料沿平面和厚度方向的原子结构

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