摘要翻译：
我们用一个简单的统计力学模型研究了聚合物链在弱溶剂中的构象，包括弯曲刚度和不弯曲刚度。对于长度为n=55的链，该模型可以用精确的枚举技术精确求解。本文详细分析了大而有限N的恒力系综和恒距离系综在低温下的区别，在恒力系综中，力-伸展曲线表现出多个平台（中间态），而在$N到infty$极限时，力-伸展曲线表现为突然向伸展态的转变。在等距离系综中，同一曲线提供了对拉力和压缩力的统一响应，与最近的实验结果定性一致。我们确定了一个与$n$成正比的交叉长度，在该交叉长度以下，展开的临界力随温度而减小，而在该交叉长度以上，展开的临界力随温度而增大。最后，在蛋白质展开实验中观察到，刚性链的力-伸展曲线表现出锯齿状行为。
---
英文标题：
《Modeling force-induced bio-polymer unfolding》
---
作者：
Anthony J. Guttmann, Jesper L. Jacobsen, Iwan Jensen and Sanjay Kumar
---
最新提交年份：
2007
---
分类信息：

一级分类：Physics        物理学
二级分类：Statistical Mechanics        统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
--
一级分类：Physics        物理学
二级分类：Soft Condensed Matter        软凝聚态物质
分类描述：Membranes, polymers, liquid crystals, glasses, colloids, granular matter
膜，聚合物，液晶，玻璃，胶体，颗粒物质
--

---
英文摘要：
  We study the conformations of polymer chains in a poor solvent, with and without bending rigidity, by means of a simple statistical mechanics model. This model can be exactly solved for chains of length up to N=55 using exact enumeration techniques. We analyze in details the differences between the constant force and constant distance ensembles for large but finite N. At low temperatures, and in the constant force ensemble, the force-extension curve shows multiple plateaus (intermediate states), in contrast with the abrupt transition to an extended state prevailing in the $N \to \infty$ limit. In the constant distance ensemble, the same curve provides a unified response to pulling and compressing forces, and agrees qualitatively with recent experimental results. We identify a cross-over length, proportional to $N$, below which the critical force of unfolding decreases with temperature, while above, it increases wiyh temperature. Finally, the force-extension curve for stiff chains exhibits "saw-tooth" like behavior, as observed in protein unfolding experiments.
---
PDF链接：
https://arxiv.org/pdf/711.3482