The Kinetics of First Order Phase Transitions

一阶相变动力学

• 批准号: 0302598
• 负责人: James Gunton
• 金额: $ 31.8万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-15 至 2006-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0302598&HistoricalAwards=false
• 关键词: Kinetics; First; Order; Phase; Transitions

This award supports theoretical research that deals with the kinetics of phase separation for several closely related problems. The first problem is a study of protein crystallization, in which compact protein nanoparticles self-assemble from solution to form crystal droplets. Understanding protein function is a major field of activity; determining the structure of protein molecules is essential to an understanding of the structure-function relationships. The primary tool for protein structure remains the diffraction of X-rays by protein crystals. Therefore the objective is to determine the conditions necessary to obtain high quality protein crystals from solution. Renormalization group techniques will be used to determine accurately the thermodynamic properties and phase boundaries of current models of proteins in solution, particularly in the vicinity of the metastable critical points where nucleation is enhanced. Density functional methods will be used to calculate the nucleation rate and growth of the protein crystal droplets. The second topic is the crystallization of Lennard-Jones fluids; the objective is to obtain a better theoretical understanding of this important kinetic process. Finite size scaling methods will be used to determine the free energy landscape for the liquid -solid phase transition, which is a prerequisite to understanding the kinetics of phase separation. This study will also link microscopic and mesoscopic length scales for Lennard-Jones fluids. The dynamics of crystal growth will also be investigated, based on a model with an order parameter that continuously distorts a crystal with fcc symmetry to one with bcc symmetry. These symmetries are important in the crystallization process. A smaller part of the research will involve a study of a generalized model for the kinetics of three-phase coexistence in complex fluids, which has recently been the subject of investigation. The objective is to gain a better understanding of the kinetic pathways to three-phase coexistence.%%%This award supports theoretical research that deals with the kinetics of phase separation for several closely related problems. The research will improve our understanding of common phase changes in a number of materials. One system of interest will be the crystallization of protein crystals from solution. This may lead to better crystals and, subsequently, a better understanding of the properties of proteins.***

该奖项支持的理论研究，涉及相分离的动力学几个密切相关的问题。 第一个问题是蛋白质结晶的研究，其中紧凑的蛋白质纳米颗粒从溶液中自组装形成晶体液滴。 了解蛋白质功能是一个主要的活动领域;确定蛋白质分子的结构对于了解结构与功能关系至关重要。 蛋白质结构的主要工具仍然是蛋白质晶体的X射线衍射。 因此，目的是确定从溶液中获得高质量蛋白质晶体所需的条件。 重整化群技术将被用来准确地确定当前模型的蛋白质在溶液中的热力学性质和相边界，特别是在亚稳临界点附近的成核增强。 密度泛函方法将用于计算蛋白质晶体液滴的成核速率和生长。 第二个主题是Lennard-Jones流体的结晶;目的是对这一重要的动力学过程有更好的理论理解。 有限尺寸缩放方法将用于确定液-固相变的自由能景观，这是理解相分离动力学的先决条件。 这项研究还将链接微观和介观长度尺度的Lennard-Jones流体。 晶体生长的动力学也将被调查，基于一个模型的顺序参数，不断扭曲的晶体与面心立方对称的一个体心立方对称。 这些对称性在结晶过程中很重要。 研究的一小部分将涉及复杂流体中三相共存动力学的广义模型的研究，这是最近的调查主题。 目的是更好地了解三相共存的动力学途径。%该奖项支持的理论研究，涉及相分离的动力学几个密切相关的问题。 这项研究将提高我们对许多材料中常见相变的理解。 感兴趣的一个系统将是从溶液中结晶蛋白质晶体。 这可能会导致更好的晶体，并随后更好地了解蛋白质的性质。