中文摘要：

本文针对α-Al2O3有序介孔材料的导热特性开展分子动力学模拟分析.提出了一种保证电中性的孔道结构构造方法;采用逆非平衡分子动力学方法（muller-plathe法）,选取Matsui势为作用势,模拟计算了Al2O3介孔晶体材料在不同环境温度下沿孔道轴向方向的热导率;并借助全面实验分析法,设计了模拟条件,以考察孔径和孔隙率对热导率的影响.模拟结果显示：介孔Al2O3热导率先随温度的升高呈上升趋势,并在200—400 K之间取得极值;而后在400—1400 K范围内,热导率随温度的升高几乎呈线性下降.孔隙率一定时,随孔径增大,介孔Al2O3材料比表面积降低,界面散射的抑制作用减弱,使材料热导率略有上升;孔径一定时,随孔隙率上升,孔道壁面声子数减少,材料热导率下降明显;相对于孔径因素,材料孔隙率对声子导热影响更大.

英文摘要：

In this paper,molecular dynamics simulation was performed to predict the thermal conductivities of ordered mesoporous α-Al2 O3.A kind of porous structure was proposed to guarantee the electrical neutrality.Based on the Matsui potential,the nonequilibrium molecular dynamics method adapted by Müller-Plathe was used to calculate the lattice thermal conductivity of mesoporous alumina along the axial direction of pore at various temperatures.Efects of pore size and porosity were also investigated.It turns out that with increasing temperature the thermal conductivity of mesoporous α-Al2 O3 rises frst until the temperature reaches 200—400 K,then decreases almost linearly.In addition,as the pore size gets larger,the specifc surface area decreases,and the thermal conductivity increases because the boundary scattering has been weakened.On the other hand,the number of phonons in the pore wall decreases greatly with increasing porosity,thus dramatically reducing the thermal conductivity of the mesoporous material.Range analysis shows that the porosity is more infuential than the pore size on the thermal conductivity of mesoporous materials.