U.S.-France Planning Visit: Nanostructured Iron Oxides: Nature's Signatures of Environmental Change

美国-法国计划访问：纳米结构氧化铁：性质？这项提案将资助一个美国研究小组对法国进行为期六天的访问，与法国同事共同制定一项研究计划，研究天然氧化铁纳米颗粒，这种纳米颗粒可以灵敏地记录气候和人为引起的环境变化。美国团队包括李·佩恩博士、苏比尔·班纳吉博士、明尼苏达大学双城分校的初级研究员和两名研究生，以及加州大学的两名同事。法国研究小组由巴黎大学的菲利普·圣塔维特教授领导。美国参与者是纳米粒子化学、合成、磁学和晶体学方面的专家。法国参与者是x射线磁性圆二色性和中子散射方面的专家。后一种技术可以为氧化铁纳米颗粒最外层“壳”的独特磁自旋方向提供强有力的测试。美国团队正在发展一个中心假设，处理氧化铁纳米颗粒的核壳磁性和化学结构的想法，并阐明该结构及其对铁纳米颗粒化学行为的影响（例如，纳米颗粒表面的氧化还原化学）对于发展精确描述由环境变化带来的磁性和化学变化至关重要。因此，这项合作将导致第一次完整的磁性和化学描述，从而能够根据过去降雨和温度的主要变化对土壤和沉积物中目前的磁性观测进行严格的解释。这种定量解释需要作为测试美国和其他地方正在开发的数值区域气候变化模型的基准。

OISE-0834047 U.S.-France Planning Visit: Nanostructured Iron Oxides: Nature?s Signature of Environmental ChangeThis proposal will fund a six day visit to France for a team of U.S. researchers to develop a joint research proposal with French colleagues dealing with natural iron oxide nanoparticles that act as sensitive recorders of climate- and human-induced environmental changes. The U.S. team includes Dr. Lee Penn, Dr. Subir Banerjee, a junior research associate and two graduate students for the University of Minnesota-Twin Cities, as well as two colleagues from the University of California. The French team is led by Professor Philippe Sainctavit of the University of Paris. The U.S. participants are experts in nanoparticle chemistry, synthesis, magnetism, and crystallography. The French participants are experts in X-ray magnetic circular dichroism and neutron scattering. These latter techniques can provide powerful tests for unique magnetic spin orientations in the outermost 'shells' of the iron oxide nanoparticles. The U.S. team is developing a central hypothesis dealing with the idea of a core-shell magnetic and chemical structure of the iron oxide nanoparticles, and elucidating that structure and its impact on the chemical behavior (e.g., redox chemistry at nanoparticle surfaces) of iron nanoparticles is critical to the development of precise descriptions of magnetic and chemical changes brought about by environmental changes. Thus, the collaboration should lead to the first complete magnetic and chemical description enabling rigorous interpretations of current magnetic observations in soils and sediments in terms of past major changes in rainfall and temperature. Such quantitative interpretations are needed to act as benchmarks for testing numerical regional climate change models now being developed in the United States and elsewhere.