Magnetic Resonance Studies of Solids

固体的磁共振研究

• 批准号: 9403667
• 负责人: Mark Conradi
• 金额: $ 25.5万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9403667&HistoricalAwards=false
• 关键词: Magnetic; Resonance; Studies; Solids

9403667 Conradi Magic-angle spinning of metal-deuterides will yield separate, resolved nuclear magnetic resonance (NMR) lines for Deuterium atoms at inequivalent sites. This technique will be used to understand the site occupation in metallic alloys and compounds, to assist in the development of improved materials for hydrogen fuel storage and electrochemical cells. The anomalous relaxation in many metal-hydrides at high temperatures may arise from rapid gas-solid exchange of hydrogen molecules. Argon overpressures can reduce the gas-phase relaxation and thereby test this mechanism, specifically in the face centered cubic dihydrides. Nanocomposites are a new class of high strength, though materials made by compaction of extremely small (e.g. 20 nm) grains, sometimes in a more ductile matrix. To understand their unusual properties, NMR will probe the crucial interfaces. Specifically, NMR will determine the interfacial area on an atomic scale and the nature of core-cladding bonding. Techniques will be developed for detection, measurement, and manipulation of unusually broad resonances. Applications will include double-resonance distance determinations in biological systems between Nitrogen fourteen and Carbon thirteen. % % % % Metal hydrides are attractive candidates for clean energy technologies, for hydrogen fuel storage and electrical batteries. The location of Hydrogen (or Deuterium) atoms in the structures will be determined by applying magic-angle spinning nuclear magnetic magnetic resonance to deuterided metallic alloys and compounds. The results will direct the development of improved hydrogen storage materials. At high temperatures, many metals- hydrides exhibit an unexplained mechanism of spin-relaxation. One suggestion is that rapid exchange between the gas and solid occurs; more exotic explanations have also been proposed. The role of hydrogen in the unexplained relaxation will be tested. Nanocomposites are a new class of high stre ngth, tough materials made by compaction of extremely small (20 nm) grains, often in more ductile matrix. The interfaces grain are crucial to the mechanical properties. Nuclear magnetic resonance (NMR) will be used to measure the interfacial area on an atomic scale and to determine the nature of the core-cladding bond. Techniques will be developed for the detection, measurement and manipulation of very broad NMR lines, which otherwise unusable. Applications to biological structures and the detection of Nitrogen (e.g. in explosives) will be pursued. ***

金属-氘原子的魔角旋转将产生独立的、可分辨的核磁共振（NMR）线，用于不相等位置的氘原子。该技术将用于了解金属合金和化合物中的位置占用，以协助开发用于氢燃料储存和电化学电池的改进材料。许多金属氢化物在高温下的反常弛豫可能是由氢分子的快速气固交换引起的。氩气超压可以减少气相弛豫，从而测试这种机制，特别是在面心立方二氢化物中。纳米复合材料是一种新型的高强度材料，虽然这种材料是由极小的颗粒（例如20纳米）压实而成，有时是在更具延展性的基体中。为了了解它们不同寻常的性质，核磁共振将探测关键的界面。具体来说，核磁共振将确定原子尺度上的界面面积和核包层键合的性质。将开发用于检测、测量和操纵异常宽共振的技术。应用将包括生物系统中氮14和碳13之间的双共振距离测定。% % % %金属氢化物是清洁能源技术、氢燃料储存和电池的有吸引力的候选者。氢（或氘）原子在结构中的位置将通过对氘化金属合金和化合物应用魔角自旋核磁共振来确定。研究结果将指导改进储氢材料的开发。在高温下，许多金属氢化物表现出一种无法解释的自旋松弛机制。一种说法是气体和固体之间发生了快速交换；更奇特的解释也被提出。氢在无法解释的弛豫中的作用将被测试。纳米复合材料是一种新型的高强度、高韧性材料，通常是由极小的（20纳米）颗粒压实而成，通常是在更具延展性的基体中。界面晶粒对材料的力学性能起着至关重要的作用。核磁共振（NMR）将用于在原子尺度上测量界面面积，并确定核心-包层键的性质。将开发用于检测、测量和操作非常宽的核磁共振谱线的技术，否则这些谱线将无法使用。应用于生物结构和氮的检测（如炸药）将继续进行。＊＊＊