一维非线性功能梯度材料的热整流反转

采用非平衡分子动力学方法,研究了一维非线性功能梯度材料的不对称热传导性质.通过耦合两段Frenkel-Kontorova链,并引入线性质量梯度,研究平均温度、界面耦合强度及体系大小对热整流的影响.结果表明,当界面耦合强度较小,并在特定的体系中时,通过调节热浴温差来控制系统的热整流方向,无需进行结构重建,在原结构中就能进行热整流方向的控制.讨论了该系统在实验制备及应用方面的可能性.

Thermal Rectification Reversal in One-dimensional Nonlinear Function Graded Materials

The asymmetric heat conduction in one dimensional function graded materials consisting of two segment Frenkel-Kontorova chains was investigated by using nonequilibrium molecular dynamics simulations. The calculated results show that the rectifying direction of the system can be reversed only by adjusting the thermal bias. The rectification reversal is caused directly by the negative differential thermal resistance, and relies on the properties of interface and system size. It is interesting that, for specific materials the rectifying direction can be reversed only by adjusting the thermal bias. Considering the novel asymmetric heat conduction in the system, possible applications to manage the thermal rectification in situ directionally without re-building the structure were discussed.