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这是一个CAREER奖，进行理论研究和开发相关的教育活动。 特别是，首席研究员将研究手性分子系统，无论是在稀释极限通过研究单一手性聚合物，如DNA，以及在半稀释极限，它们形成手性液晶。 在稀释极限中，自避免随机游动和n分量伊辛模型之间的精确映射的推广，当n接近零时，可以用来研究手征随机游动。 正如单次自避免行走理论可以用来研究聚合物的半稀熔体一样，这种扩展也可以用来研究拓扑连接聚合物的半稀熔体。 我们的计划是通过一些实验来实现这一点，并通过与数值计算的比较来增强分析理论。 在更浓的状态下，手性聚合物可以形成液晶相，例如聚合物双相和柱状六方相。 通常，手性相互作用受到分子的液晶堆积的阻碍。 最近对DNA的实验似乎发现了一个不存在手性的受挫阶段，尽管理论表明没有受挫。 将追求的手性相互作用的结晶或液晶顺序的效果进行广泛的分析作为一个可能的解释比预期的手性在观察到的阶段弱。 与研究计划相结合，将开发一门针对一年级学生的自然手性对称性课程。 通过历史和科学的阐述，教师将描述手性作为介绍对称性的一种方式。 由于手征性是一个中心概念，在许多科学和工程，课程将通过历史线程触摸的使用和发现手征性在不同的情况下。 这篇论文将包括巴斯德发现的手性，蛋白质和DNA的结构，以及发现奇偶违反基本粒子物理学。 课堂上将辅以简单的演示，如玉米糖浆和石英中光的偏振旋转。 最后，讨论宇宙中的左右不对称性，即，重子不对称，将提出。 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，将对手性分子体系进行理论研究。 手征性是自然界中系统的属性，它区分了左对称性和右对称性。 手性聚合物，如DNA，将被研究，以及更浓的溶液，形成手性液晶相。 与研究计划相结合，将开发一门针对一年级学生的自然手性对称性课程。 通过历史和科学的阐述，教师将描述手性作为介绍对称性的一种方式。 由于手征性是一个中心概念，在许多科学和工程，课程将通过历史线程触摸的使用和发现手征性在不同的情况下。 这篇论文将包括巴斯德发现的手性，蛋白质和DNA的结构，以及发现奇偶违反基本粒子物理学。 课堂上将辅以简单的演示，如玉米糖浆和石英中光的偏振旋转。 最后，讨论宇宙中的左右不对称性，即，重子不对称，将提出。 ***