CAREER: Chiral Molecules, Structures and Materials

职业：手性分子、结构和材料

• 批准号: 9732963
• 负责人: Randall Kamien
• 金额: $ 20万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-15 至 2003-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9732963&HistoricalAwards=false
• 关键词: CAREER; Chiral; Molecules; Structures; Materials

9732963 Kamien This is a CAREER award to conduct theoretical research and to develop associated education activities. In particular, the principal investigator will study chiral molecular systems, both in the dilute limit by studying single chiral polymers, such as DNA, as well as in the semi-dilute limit where they form chiral liquid crystals. In the dilute limit a generalization of the exact mapping between self-avoiding random walks and the n-component Ising model, as n approaches zero, can be used to study chiral random walks. Just as the theory of a single self-avoiding walk can be used to study a semi-dilute melt of polymers, this extension can be used to study a semi-dilute melt of topologically linked polymers. The plan is to pursue this in connection with a number of experiments and to augment analytical theory with comparison to numerics. In the more concentrated regime, chiral polymers can form liquid crystalline phases such as the polymer cholesteric phase and the columnar hexagonal phase. Often, the chiral interactions are frustrated by the liquid crystalline packing of the molecules. Recent experiments on DNA appear to find a frustrated phase in which chirality is absent although theory suggests there is no frustration. An extensive analysis of the effect of the crystalline or liquid-crystalline order on the chiral interaction will be pursued as a possible explanation of the weaker than expected chirality in the observed phase. Integrated with the research program, a course will be developed aimed at first-year students on the subject of chiral symmetry in nature. Through both historic and scientific exposition the instructor will describe chirality as a way of introducing the idea of symmetry. Since chirality is a central notion in much of science and engineering, the course will thread through history touching on the use and discovery of chirality in different contexts. This discourse will include Pasteur's discovery of chirality, the structure of proteins and DNA as well as the discovery of parity violation in elementary particle physics. Lectures will be supplemented with simple demonstrations, such as rotation of the polarization of light in corn syrup and quartz. Finally, a discussion of left-right asymmetry in the Universe, i.e., baryon asymmetry, will be presented. %%% This is a CAREER award which integrates research and education. In this particular case, theoretical research will be conducted on the chiral molecular systems. Chirality is the property of systems in nature which distinguishes between left and right symmetry. Chiral polymers, such as DNA, will be studied as well as more concentrated solutions which form chiral liquid crystal phases. Integrated with the research program, a course will be developed aimed at first-year students on the subject of chiral symmetry in nature. Through both historic and scientific exposition the instructor will describe chirality as a way of introducing the idea of symmetry. Since chirality is a central notion in much of science and engineering, the course will thread through history touching on the use and discovery of chirality in different contexts. This discourse will include Pasteur's discovery of chirality, the structure of proteins and DNA as well as the discovery of parity violation in elementary particle physics. Lectures will be supplemented with simple demonstrations, such as rotation of the polarization of light in corn syrup and quartz. Finally, a discussion of left-right asymmetry in the Universe, i.e., baryon asymmetry, will be presented. ***

9732963 Kamien 这是一项职业奖，旨在进行理论研究和开展相关教育活动。 特别是，首席研究员将研究手性分子系统，包括在稀释极限下研究单一手性聚合物（例如 DNA），以及在半稀释极限下形成手性液晶。 在稀极限下，当 n 接近零时，自回避随机游走和 n 分量伊辛模型之间的精确映射的推广可用于研究手性随机游走。 正如单次自回避行走理论可用于研究聚合物的半稀熔体一样，该扩展可用于研究拓扑连接聚合物的半稀熔体。 该计划是通过大量实验来实现这一点，并通过与数值比较来增强分析理论。 在更浓缩的状态下，手性聚合物可以形成液晶相，例如聚合物胆甾相和柱状六方相。 通常，手性相互作用会因分子的液晶堆积而受到抑制。 最近的 DNA 实验似乎发现了一个手性不存在的受挫阶段，尽管理论表明不存在受挫阶段。 将对晶体或液晶顺序对手性相互作用的影响进行广泛分析，作为观察相中手性弱于预期的可能解释。 与研究计划相结合，将为一年级学生开发一门关于自然界手性对称性的课程。 通过历史和科学的阐述，讲师将描述手性作为引入对称概念的一种方式。 由于手性是许多科学和工程的核心概念，因此本课程将贯穿历史，涉及不同背景下手性的使用和发现。 本演讲将包括巴斯德对手性的发现、蛋白质和 DNA 的结构以及基本粒子物理学中宇称不守恒的发现。 讲座将辅以简单的演示，例如玉米糖浆和石英中光的偏振旋转。 最后，将讨论宇宙中的左右不对称性，即重子不对称性。 %%% 这是一个集研究和教育于一体的职业奖。 在这种特殊情况下，将对手性分子系统进行理论研究。 手性是自然界系统的属性，它区分左对称性和右对称性。 将研究手性聚合物，例如 DNA，以及形成手性液晶相的更浓缩的溶液。 与研究计划相结合，将为一年级学生开发一门关于自然界手性对称性的课程。 通过历史和科学的阐述，讲师将描述手性作为引入对称概念的一种方式。 由于手性是许多科学和工程的核心概念，因此本课程将贯穿历史，涉及不同背景下手性的使用和发现。 本演讲将包括巴斯德对手性的发现、蛋白质和 DNA 的结构以及基本粒子物理学中宇称不守恒的发现。 讲座将辅以简单的演示，例如玉米糖浆和石英中光的偏振旋转。 最后，将讨论宇宙中的左右不对称性，即重子不对称性。 ***