Delgado-Buscalioni Rafael
Departamento de Ciencias y Técnicas Fisicoquímicas, Universidad de Educación a Distancia, C/Senda del Rey, 9, Madrid 28040, Spain.
Phys Rev Lett. 2006 Mar 3;96(8):088303. doi: 10.1103/PhysRevLett.96.088303. Epub 2006 Mar 2.
The long-time dynamics of a single end-tethered chain under shear flow are studied using molecular and Brownian dynamics simulations of a flexible polymer. As observed in previous experiments with tethered DNA [Phys. Rev. Lett. 84, 4769 (2000)], under a flow sheared at constant rate the chain performs a cyclic motion. But, contrary to what has been previously suggested, a well-defined characteristic period exists and it is clearly revealed in the cross spectra of the chain extension along flow and gradient directions. The main cycling time scales like the time needed to stretch the polymer by convection, being about 10 times the relaxation time of the chain in flow. This coherent recursive motion introduces long memory in the fluid and suggests resonance effects under periodic external forcing.
使用柔性聚合物的分子动力学和布朗动力学模拟，研究了单根末端拴系链在剪切流作用下的长期动力学。正如先前在拴系DNA实验中所观察到的[《物理评论快报》84, 4769 (2000)]，在以恒定速率剪切的流场中，链会进行循环运动。但是，与先前的推测相反，存在一个明确的特征周期，并且在沿流动方向和梯度方向的链伸展的交叉谱中清晰地显示出来。主要的循环时间尺度，如通过对流拉伸聚合物所需的时间，约为链在流场中弛豫时间的10倍。这种相干的递归运动在流体中引入了长记忆，并表明在周期性外部强迫下存在共振效应。
