NIRT: Reduced Degree of Freedom Predictive Methods for Control and Design of Interfaces in Nanofeatured Systems: Nanocrystalline Materials, Sensors and Composites

这是一个纳米尺度跨学科研究团队（NIRT）奖，以响应提交给纳米科学与工程（NSE）倡议的提案。该研究涉及纳米材料的多尺度理论和建模。一种跨越多个长度和时间尺度的跨学科有限自由度（LDF）材料建模方法将被开发用于精确建模纳米特征材料中的界面。建模层次将原子尺度上的量子力学、亚微米尺度上的解析模型和微米尺度以上的连续体缺陷建模耦合在一起，将允许从原子到宏观尺度以及从宏观到原子尺度的加工-结构-性质关系的精确控制和预测。该方法超越了将量子力嵌入到连续环境中的子系统，并将准确预测导致纳米特征固体宏观力学性能的主要原子级物理机制，以及导致特定目标纳米结构和相关性能的宏观加工条件的预测。两种特定的纳米材料将被建模，并通过NIRT合作者进行的实验验证结果。首先是纳米晶体固体，其中预测的加工-结构-性能关系将与NCSU的Carl Koch教授所做的实验测量进行比较。第二种材料是纳米金刚石陶瓷复合材料，其中建模将用于预测界面能量，缺陷扩展速率和相关的宏观性能，例如韧性。量子力学以两种方式进入：(1)精确计算下一层次所需的界面属性；(2)作为一个框架，量子和经典自由度可以在嵌入纳米组件周围的固体局部区域中加权，从而为嵌入在固体环境中的量子系统提供LDF模型。量子力学的后一种作用是从基本层面上理解量子自由度，以及量子受限结构（如嵌入固体中的量子点）的功能如何依赖于局部环境的特征，以及通过我们的力学建模，该局部环境如何反过来依赖于宏观尺度变量，如加工条件、施加应力等。这种独特的能力，利用了我们团队在将量子理论应用于工程系统和固体力学方面的协同优势，将有助于机械传感器和相关功能结构的集成设计。研究团队的成员来自两个学院和四个部门，他们拥有互补的专业知识，涵盖了最先进的密度泛函计算和量子形式，以及材料的连续介质力学方法。四家合作伙伴将为提议的方法提供实验验证，为NIRT带来新的建模工作，并帮助将结果转化为工业和政府实验室。这些合作伙伴是位于三角研究园的国际技术中心、美国宇航局-艾姆斯纳米技术中心、俄罗斯乌法金属超塑性问题研究所和橡树岭国家实验室。通过合作研究、交叉上市课程、研讨会以及与国际学者的互动等形式的跨学科培训，将培养出具有专业知识的新一代科学家和工程师，他们将不局限于单一的建模技术，而是训练他们使用超越科学和工程学科之间传统障碍的方法，以广阔的前景来解决复杂问题。外展将包括纳米技术的现场和网络教程，与高中生和他们的老师在暑期项目中合作，以及参与纳米技术公共影响的国家委员会。来自当地两所大学圣奥古斯丁大学和梅雷迪思学院的暑期学生将在NIRT的研究项目中实习。%%%这是一个纳米尺度跨学科研究团队（NIRT）奖，以响应提交给纳米科学与工程（NSE）倡议的提案。该研究涉及纳米材料的多尺度理论和建模。一种跨越多个长度和时间尺度的跨学科有限自由度（LDF）材料建模方法将被开发用于精确建模纳米特征材料中的界面。研究团队的成员来自两个学院和四个部门，他们拥有互补的专业知识，涵盖了最先进的密度泛函计算和量子形式，以及材料的连续介质力学方法。四家合作伙伴将为提议的方法提供实验验证，为NIRT带来新的建模工作，并帮助将结果转化为工业和政府实验室。这些合作伙伴是位于三角研究园的国际技术中心、美国宇航局-艾姆斯纳米技术中心、俄罗斯乌法金属超塑性问题研究所和橡树岭国家实验室。通过合作研究、交叉上市课程、研讨会以及与国际学者的互动等形式的跨学科培训，将培养出具有专业知识的新一代科学家和工程师，他们将不局限于单一的建模技术，而是训练他们使用超越科学和工程学科之间传统障碍的方法，以广阔的前景来解决复杂问题。外展将包括纳米技术的现场和网络教程，与高中生和他们的老师在暑期项目中合作，以及参与纳米技术公共影响的国家委员会。来自当地两所大学圣奥古斯丁大学和梅雷迪思学院的暑期学生将在NIRT的研究项目中实习

This is a Nanoscale Interdisciplinary Research Team (NIRT) award in response to a proposal submitted to the Nanoscience and Engineering (NSE) initiative. The research involves multiscale theory and modeling of nanoscale materials. An interdisciplinary limited degrees of freedom (LDF) hierarchy of materials modeling methods that spans multiple length and time scales will be developed for accurately modeling interfaces in nanofeatured materials. The modeling hierarchy, which couples quantum mechanics at the atomic scale, analytic models at the submicron scale and continuum defect modeling above the micron scale, will allow for the accurate control and prediction of processing-structure-property relations from both the atomic up to the macroscale, and from the macroscale down to the atomic scale. The methodology goes beyond embedding subsystems with quantum forces into a continuum environment, and will accurately predict the dominant atomic-level physical mechanisms that lead to macroscale mechanical properties of nanofeatured solids, as well as predictions for macroscale processing conditions that lead to specific target nanostructures and associated properties. Two specific nanofeatured materials will be modeled, with results validated against experiments carried out by NIRT collaborators. The first is nanocrystalline solids, where predicted processing-structure-property relations will be compared to experimental measurements made by Professor Carl Koch at NCSU. The second material is nanodiamond cermet composites, where modeling will be used to predict interface energies, defect propagation rates, and associated macroscale properties, e.g., toughness. Quantum mechanics enters in two ways: (1) to accurately calculate interface properties that are needed in the next level of the hierarchy, and (2) as a framework from which quantum and classical degrees of freedom can be weighted in a localized region of a solid surrounding an embedded nanocomponent, thereby providing a LDF model for quantum systems embedded in a solid environment. The latter role for quantum mechanics is to understand from a fundamental level how the quantum degrees of freedom, and hence the functionality of a quantum-confined structure, like a quantum dot embedded in a solid, may depend on the features of the local environment, and through our mechanics modeling how this local environment in turn depends on macroscale variables such as processing conditions, applied stress, etc. This unique capability, which takes synergistic advantage of the experience of our team in applying quantum theory to engineering systems and in solid mechanics, will facilitate the integrated design of mechanical sensors and related functional structures.Members of the research team come from two colleges and four departments and have complementary expertise that spans state-of-the-art density functional calculations and quantum formalisms to continuum mechanics-of-materials methodologies. Four partners will provide experimental validation of proposed methods, bring new modeling efforts into the NIRT, and help transition results to industrial and government laboratories. These partners are the International Technology Center in Research Triangle Park, the NASA-Ames Center for Nanotechnology, the Institute for Metals Superplasticity Problems, Ufa, Russia, and Oak Ridge National Laboratory. Through an interdisciplinary training effort in the form of collaborative research, cross-listed courses, seminars, and interactions with international scholars, a new generation of scientists and engineers will be produced with expertise that is not limited to a single modeling technique, but rather who are trained to attack complicated problems with a broad outlook using methods that transcend traditional barriers between science and engineering disciplines. Outreach will include live and web-based tutorials on nanotechnology, working with high school students and their teachers in summer programs, and participation in national committees on public implications of nanotechnology. Summer students from two local universities, St. Augustine's University and Meredith College, will intern with NIRT research projects.%%% This is a Nanoscale Interdisciplinary Research Team (NIRT) award in response to a proposal submitted to the Nanoscience and Engineering (NSE) initiative. The research involves multiscale theory and modeling of nanoscale materials. An interdisciplinary limited degrees of freedom (LDF) hierarchy of materials modeling methods that spans multiple length and time scales will be developed for accurately modeling interfaces in nanofeatured materials. Members of the research team come from two colleges and four departments and have complementary expertise that spans state-of-the-art density functional calculations and quantum formalisms to continuum mechanics-of-materials methodologies. Four partners will provide experimental validation of proposed methods, bring new modeling efforts into the NIRT, and help transition results to industrial and government laboratories. These partners are the International Technology Center in Research Triangle Park, the NASA-Ames Center for Nanotechnology, the Institute for Metals Superplasticity Problems, Ufa, Russia, and Oak Ridge National Laboratory. Through an interdisciplinary training effort in the form of collaborative research, cross-listed courses, seminars, and interactions with international scholars, a new generation of scientists and engineers will be produced with expertise that is not limited to a single modeling technique, but rather who are trained to attack complicated problems with a broad outlook using methods that transcend traditional barriers between science and engineering disciplines. Outreach will include live and web-based tutorials on nanotechnology, working with high school students and their teachers in summer programs, and participation in national committees on public implications of nanotechnology. Summer students from two local universities, St. Augustine's University and Meredith College, will intern with NIRT research projects.***