High-pressure Behavior of Framework Minerals

骨架矿物的高压行为

• 批准号: 0738692
• 负责人: Nancy Ross
• 金额: $ 34.91万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0738692&HistoricalAwards=false
• 关键词: pressure; Behavior; Framework; Minerals

Intellectual Merit. Common framework minerals, such as feldspars and perovskites are ubiquitous components of the Earth's crust and lower mantle, respectively, but their structures and properties remain poorly understood because of their complex behavior, especially at high pressure. With the support of two previous NSF-EAR grants, the PIs have gained significant insight into the high-pressure behavior of feldspars and perovskites via development of very precise single-crystal X-ray diffraction techniques to measure small changes in structures at high pressures. This work resulted in a model that successfully predicts phase relations and densities of the pure end member minerals. Funding is requested to extend this work to more natural feldspar and perovskite solid solutions in order to elucidate substitution mechanisms and effects of various element and defect substitutions on elastic and thermodynamic properties. The proposed project will support three new, important initiatives:1. To determine the crystal chemical principles that control compression of other important groups of framework minerals.2. To gain an atomic-scale understanding of these principles from electron density calculations.3. To investigate the dynamics of framework minerals and their role in elasticity.Technical developments will continue to further improve structure determinations at high pressures. The proposed research will contribute towards an ultimate goal to develop a crystal chemical "toolbox" to predict the structural evolution of framework minerals as a function of pressure, temperature and composition.Broader Impacts. This research program will train scientists at all levels, including undergraduates, graduates, postdoctoral scientists and collaborating senior research faculty. Individual studies form the basis of research projects for undergraduates. Graduate students are fully trained in crystallography and mineral physics and are provided opportunities to visit other laboratories and national facilities. Training opportunities are extended to graduate students from other universities through research visits to Virginia Tech. Post-docs are given the opportunity to develop their research skills, and also supervise and train students in the laboratory. The award of this grant will also enable continuation of inter-disciplinary outreach activities, including hosting of a summer crystallography workshop for students and faculty from regional undergraduate institutions. Framework structures attract great interest because of their interesting technological properties. Perovskites, for example, are commonly used as electronic materials, including superconductors, ferroelastics and ferroelectric device materials. Research on the factors that influence the structural state in perovskites has attracted interest outside the earth science community and it is expected that results obtained with this grant will have application in materials sciences and engineering.

智力优点。常见的骨架矿物，如长石和钙钛矿，分别是地壳和下地幔中普遍存在的成分，但由于其复杂的行为，尤其是在高压下，它们的结构和性质仍然知之甚少。在之前两项 NSF-EAR 资助的支持下，PI 通过开发非常精确的单晶 X 射线衍射技术来测量高压下结构的微小变化，对长石和钙钛矿的高压行为有了深入的了解。这项工作产生了一个模型，可以成功预测纯端元矿物的相关系和密度。需要资金将这项工作扩展到更天然的长石和钙钛矿固溶体，以阐明替代机制以及各种元素和缺陷替代对弹性和热力学性质的影响。拟议的项目将支持三项新的重要举措：1．确定控制其他重要骨架矿物的压缩的晶体化学原理。2．从电子密度计算中获得对这些原理的原子尺度的理解。3．研究骨架矿物的动力学及其在弹性中的作用。技术发展将继续进一步改进高压下的结构测定。拟议的研究将有助于实现开发晶体化学“工具箱”的最终目标，以预测框架矿物作为压力、温度和成分函数的结构演化。更广泛的影响。该研究计划将培训各级科学家，包括本科生、研究生、博士后科学家和合作高级研究人员。个人研究构成了本科生研究项目的基础。研究生接受了晶体学和矿物物理学方面的全面培训，并有机会参观其他实验室和国家设施。通过对弗吉尼亚理工大学的研究访问，向其他大学的研究生提供培训机会。博士后有机会发展他们的研究技能，并在实验室监督和培训学生。这笔赠款的授予还将有助于继续开展跨学科外展活动，包括为地区本科院校的学生和教师举办夏季晶体学研讨会。框架结构因其有趣的技术特性而引起了极大的兴趣。例如，钙钛矿通常用作电子材料，包括超导体、铁弹性体和铁电器件材料。对影响钙钛矿结构状态的因素的研究引起了地球科学界以外的兴趣，预计这笔资助获得的结果将在材料科学和工程领域得到应用。