非平衡态/不可逆过程的热力学理论(Ⅱ)

<正> 7 解的唯一性 如果不考虑非平衡态和不可逆性,则等能密度理论中的基本命题与经典弹性理论中的在形式上完全相同。无论整个系统的动能是大还是小,图6中(sumform)_o上的面力T_i和在(sumform)_c和在的位移u_i将始终在空间坐标系x_i和时刻i下给出。与一般力学中相同,必须知道有关位移u_i及其时间导数的初始条件。它们的影响则可通过(38)和(39)向等能面转化,从而得到     

Dithienylethene-Based Single Molecular Photothermal Linear Actuator

By employing a mechanically controllable break junction technique, we have realized an ideal single molecular linear actuator based on dithienylethene (DTE) based molecular architecture, which undergoes reversible photothermal isomerization when subjected to UV irradiation under ambient conditions. As a result, open form (compressed, UV OFF) and closed form (elongated, UV ON) of dithienylethene-based molecular junctions are achieved. Interestingly, the mechanical actuation is achieved without changing the conductance of the molecular junction around the Fermi level over several cycles, which is an essential property required for an ideal single molecular actuator. Our study demonstrates a unique example of achieving a perfect balance between tunneling width and barrier height change upon photothermal isomerization, resulting in no change in conductance but a change in the molecular length, which results in mechanical actuation at the single molecular level.