低维系统中的输运和扩散行为研究

项目名称： 低维系统中的输运和扩散行为研究

项目编号： No.11335006

项目类型： 重点项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 赵鸿

作者单位： 厦门大学

项目金额： 260万元

中文摘要： 趋向平衡是非平衡态统计物理的核心问题，决定了系统输运和扩散等统计物理性质。本项目研究低维系统从近平衡态趋向平衡的问题，发展低维系统输运和扩散的一般性理论与分析方法，揭示热传导系数对系统尺寸的依赖规律、流关联函数随时间衰减的规律、物理量密度涨落的扩散规律、不同的输运过程之间的耦合关系。为此，我们不仅拟运用数值模拟和理论分析研究典型的低维流体和低维晶格模型，也拟发展大尺寸单晶石墨烯等二维材料的制备技术和低维材料热传导测量技术，借助实验研究二维材料热传导随样本尺寸的依赖关系。同时，为了理解晶格材料中的扩散运动，拟研究粒子在不同结构的二维散射子中的散射规律，揭示粒子在材料中正常扩散、超扩散、亚扩散发生的条件和机制。在深入理解输运和扩散规律的基础上，研究控制低维系统热输运的理论和方法，结合实验研究，探索利用低维特性提高热电材料性能的新途径，探索微纳米材料和器件的散热问题。

中文关键词： 非平衡态统计物理;低维系统;输运;扩散;热传导

英文摘要： One of the key issues of nonequilibrium statistical physics is how a system approaches to the equilibrium state, which determines the statistical properties of the system, such as transport and diffusion. This project will study the problem that how low-dimensional systems approach to equilibrium from a near-equilibrium state. We will develop a general theory to analyze the transport and diffusion in low-dimensional systems and then reveal the system size dependence of thermal conductivity, time decay of flux correlation function, density fluctuation of physical quantities, and coupling of transport processes. For that purpose, we will not only apply numerical simulation and theoretical analysis to study the typical low-dimensional fluids and lattice models, but also develop the technique to prepare two-dimensional materials, such as millimeter-size single-crystal graphene, and technique to measure thermal conductivity in low-dimensional materials. In particular, we will study the size dependence of thermal conductivity of two-dimensional materials experimentally. Meanwhile, as to understand the diffusion behavior in lattice systems, we will study the diffusion of particles in two-dimensional scatterers and show the condition and mechanism for the occurring of normal diffusion, superdiffusion and subdiffusion. Based on the understanding of transport and diffusion behaviors, we will develop the theory and approach to control thermal transport in low-dimensional systems. We will then explore the new approaches to enhance thermoelectric performance in low-dimensional materials and heat sinking in micro and nano materials and devices theoretically and experimentally.

英文关键词： nonequilibrium statistics;low-dimensional systems;transport;diffusion;thermal conduction