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arXiv 1902.04761cond-mat.soft
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自推进半柔性灯丝的结构和动力学

Structure and dynamics of a self-propelled semiflexible filament

Shalabh K. Anand, Sunil P. Singh

摘要:

我们使用粗粒度的布朗动力学模拟研究了自推进细丝的结构和动力学性质。沿着键矢量施加自推进力,即,与灯丝相切,它们的位置以两种不同的方式考虑。在第一种情况下,力被施加到细丝的所有珠上,这被称为均匀自推进。在这里,我们得到了一个单调减少的灵活性与佩克莱数的细丝。因此,回转半径也显示出相同的趋势。此外,纤维的回转半径对各种弯曲刚度和弯曲数具有普遍的依赖性。纤维的有效扩散系数随作用力的增大而增大,并随作用力和弯曲刚度的增大而线性增大。在第二种情况下,自推进力只施加在少数键矢量上。以周期性的方式选择作用力的位置,从灯丝的尾部开始,离开前端而不施加力。在这种情况下,细丝获得各种结构,例如棒状、螺旋状、圆形和折叠状态。从几个状态的过渡被理解的切线-切线相关性,弯曲能和扭转序参量。螺旋状态通过切线-切线相关的指数到振荡行为的交叉来识别。弯曲能的突然增加将螺旋状态分离为丝状体的折叠状态。

英文摘要:

We investigate structural and dynamical properties of a self-propelled filament using coarse-grained Brownian dynamics simulations. A self-propulsion force is applied along the bond vectors, i.e., tangent to the filament and their locations are considered in two different manners. In case one, force is applied to all beads of the filament, which is termed as homogeneous self-propulsion. Here, we obtain a monotonic decrease in the flexibility of the filament with Péclet number. Hence, radius of gyration also displays the same trend. Moreover, the radius of gyration of the filament shows universal dependence for various bending rigidities with flexure number. The effective diffusivity of the filament shows enhancement with the active force and it increases linearly with force and bending rigidity. In case two, self-propulsion force is applied only to few bond vectors. The location of active forces is chosen in a periodic manner starting from the tail of the filament and leaving the front end without force. In this case, filament acquires various structures such as rod-like, helical, circular, and folded states. The transition from several states is understood in terms of tangent-tangent correlation, bending energy and torsional order parameter. The helical state is identified through a crossover from exponential to oscillatory behavior of the tangent-tangent correlation. A sudden increase in the bending energy separates a helical to a folded states of the filament.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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