CAREER: Atomic Structure and Growth of Nano-Particles

职业：原子结构和纳米粒子的生长

• 批准号: 0449790
• 负责人: Jian-Min Zuo
• 金额: $ 61万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0449790&HistoricalAwards=false
• 关键词: CAREER; Atomic; Structure; Growth; Nano

This career proposal focuses on the structure of nano-scale atomic aggregates. The problem is important because embryonic clusters or particles form at the early stage of phase transformations and the cluster structure affects the phase transformation and microstructure evolution. Furthermore, metal particles are important industrial catalyst and nanoparticles are the building blocks for nanotechnology. This proposal will develop new approaches to structure characterization and atomic resolution imaging based on the new nano-area electron diffraction (NED) technique involving a nanometer-sized coherent beam of parallel electrons. NED allows diffraction patterns to be recorded from individual particles for 3-D structure determination. The results will contribute to the understanding of atomic structure in nanoparticles. In-situ capabilities will be developed using a modified analytical UHV scanning transmission electron microscope. The analytical capability will be very useful for studying alloying and phase separation in bimetallic nanoparticles. Insight about particle structure will be obtained by comparing experiment with molecular dynamics simulations. A goal of the project is to use the structural knowledge as a feedback to growth to improve the properties of the nano-particles. Materials to be studied include the model system of Ag nanoparticles and the eutectic Ag/Cu system. Later study will focus on magnetic alloys of Ag/Fe and Fe/Pt, and catalytic Pt/Ru to correlate structure with properties.The research will be integrated with education at several levels. This project will develop novel methods that make use of a nanometer-sized coherent beam of parallel electrons to determine atomic arrangements. The technique is general, and in principle, applicable to individual macromolecules. The in-situ capabilities to be developed will be available through the Center for Microanalysis of Materials (CMM) to the broader community. Knowledge gained will be incorporated for teaching nanostructure characterization and used for outreach activities through workshops and schools. An important aspect of the project is the creation of research and education tools in the form of web-based research software and tutorials for educators who seek to incorporate nanoscience in their own curricula. The teaching materials to be developed here will also fill a gap in current materials science education by introducing students to the concept of molecular diffraction. Graduate and undergraduate researchers will be trained through hands-on workshops, conferences and collaboration on nanoscience specific projects.

该职业提案的重点是纳米级原子聚集体的结构。这个问题很重要，因为胚胎团簇或颗粒是在相变的早期形成的，团簇结构影响相变和微观结构的演化。此外，金属颗粒是重要的工业催化剂，纳米颗粒是纳米技术的基石。该提案将基于涉及纳米级相干平行电子束的新型纳米区域电子衍射（NED）技术，开发结构表征和原子分辨率成像的新方法。 NED 可以记录单个颗粒的衍射图案，用于 3D 结构测定。结果将有助于理解纳米粒子的原子结构。将使用改进的分析型超高真空扫描透射电子显微镜来开发原位能力。该分析能力对于研究双金属纳米粒子的合金化和相分离非常有用。通过将实验与分子动力学模拟进行比较，可以获得有关颗粒结构的见解。该项目的目标是利用结构知识作为生长反馈，以改善纳米颗粒的性能。待研究的材料包括Ag纳米颗粒模型系统和共晶Ag/Cu系统。后期研究将集中在 Ag/Fe 和 Fe/Pt 磁性合金以及催化 Pt/Ru 上，以将结构与性能联系起来。该研究将与多个层次的教育相结合。该项目将开发利用纳米级平行电子相干束来确定原子排列的新颖方法。该技术是通用的，原则上适用于单个大分子。待开发的现场能力将通过材料微分析中心（CMM）向更广泛的社区提供。获得的知识将用于纳米结构表征的教学，并通过研讨会和学校用于外展活动。该项目的一个重要方面是以基于网络的研究软件和教程的形式为寻求将纳米科学纳入自己课程的教育工作者创建研究和教育工具。这里即将开发的教材也将通过向学生介绍分子衍射的概念来填补当前材料科学教育的空白。 研究生和本科生研究人员将通过纳米科学特定项目的实践研讨会、会议和合作接受培训。