Physical Knots

物理结

• 批准号: 0107209
• 负责人: Jonathan Simon
• 金额: $ 17.7万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0107209&HistoricalAwards=false
• 关键词: Physical; Knots

The investigator and his colleagues study "Physical Knots," bridging the gap between purely topological properties of knots and links, and physically realistic systems in which properties such as thickness, curvature, repelling forces, and randomness are evident. Focus areas include: understanding how random tangling increases with filament length in different kinds of systems; determining existence, uniqueness, and geometric properties of optimal conformations of knots; modeling gel electrophoresis of knotted DNA loops; understanding how the "symmetric energy" of knots models physical behavior such as accessibility of molecules to enzymes and self-irradiation of filaments that emit; determining relationships between various knot energies; understanding how knots, such as folding proteins, form in filaments with free ends.This project contributes to the understanding of one of the fundamental ways that matter behaves: a solid object occupies space; a sheet of material separates one part of space from another; and a string tangles with itself or other strings. There is growing scientific awareness that knotting and tangling happen, and are physically important, at every scale of size, from molecules such as DNA and other polymers, to magnetic field lines in the sun. But there are many basic questions that are not yet answered: How are knots and tangles created, or destroyed, in various settings? What happens when one pulls a knot tight? Why do mathematically different kinds of knots behave the way they do in physical situations? How can we model knots on the computer, and how well do the computer simulations reflect actual behavior? The combination of importance of the phenomenon, together with substantial open questions, makes this area fascinating and valuable for research. In particular, the project seeks to contribute to areas of national interest, including increasing understanding of the behavior of DNA molecules, and helping to elucidate the process of protein folding.

研究人员和他的同事们研究“物理结”，弥合纯拓扑性质的结和链接之间的差距，物理现实的系统，其中的属性，如厚度，曲率，排斥力，和随机性是显而易见的。 重点领域包括：理解随机缠结如何在不同类型的系统中随细丝长度增加;确定结的最佳构象的存在性，唯一性和几何性质;模拟打结DNA环的凝胶电泳;理解结的“对称能量”如何模拟物理行为，例如分子对酶的可及性和发射的细丝的自辐射;确定各种结能量之间的关系;了解如何结，如折叠蛋白质，形成在细丝与自由端。这个项目有助于了解的基本方式之一，物质的行为：一个固体物体占据空间;一张材料分隔空间的一部分，从另一个;和字符串缠结本身或其他字符串。 越来越多的科学家意识到，打结和缠结的发生，是物理上重要的，在每一个规模的大小，从分子，如DNA和其他聚合物，以磁场线在太阳上。 但还有许多基本问题尚未得到解答：在不同的环境中，结和缠结是如何产生或消灭的？ 当一个人拉紧一个结会发生什么？ 为什么数学上不同种类的结在物理情况下会表现出不同的行为？ 我们如何在计算机上模拟结，以及计算机模拟如何反映实际行为？ 这一现象的重要性与大量的开放性问题相结合，使这一领域具有吸引力和研究价值。 特别是，该项目旨在为国家利益领域做出贡献，包括增加对DNA分子行为的理解，并帮助阐明蛋白质折叠的过程。