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Investigation of the structure and assembly of inorganic macromolecules formed on the terrestrial surface

研究陆地表面形成的无机大分子的结构和组装

基本信息

批准号：
17340160
负责人：
KOGURE Toshihiro
金额：
$ 10.28万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

There are a number of interesting natural materials on the terrestrial surface, formed in water-abundant and oxidizing conditions at moderate temperatures. These materials are generally very fine-grained and do not have three-dimensional periodicity, unlike common crystalline minerals. From these characteristics, they may be called "inorganic macro-molecules". However, their atomic structures and textures are not well understood, owing to the very small particle size and non-periodic structure. Imogolite, smectite and some phyllosilicates with heavy stacking disorder are typical examples. The purpose of this work was to develop new methodologies and/or techniques to investigate these materials, and elucidate their structures and forming conditions on the earth.At first, we tried to determine the atomic structure of imogolite, a natural nano-tube, from the intensity distribution in electron diffraction patterns. However, a plausible model that completely explains the electron diffractio … More n patterns was not obtained. This investigation must be continued as a future research. Meanwhile, Suzuki in AIST has made a progress in finding conditions to synthesize imogolite efficiently in a laboratory.Smectite is a very fine-grained phyllosilicate, often regarded as "nanosheet". Its basic structure is a 2:1 layer with two tetrahedral sheets and one octahedral sheet between them, but the detail is not clear yet. Especially distribution of octahedral rations in the 2:1 layer is under discussion. We investigated possibility to determine the cation distribution by using high-resolution electron microscopy (HRTEM). However, it was found that intense electron beam during image recording dehydroxylates the 2:1 layer and this dehydroxylation induces cation migration. We need to find an idea to overcome this problem in future. On the other hand, we have found a novel 2:1 layer structure in the thermally dehydroxylated phase of a kind of mica, celadonite.We have made a plenty of progress to elucidate the nature of stacking disorder in various phyllosilicates in this study, by using HRTEM and simulation of powder X-ray diffraction patterns. The investigated phyllosilicates include kaolin group minerals, pyrophyllite, talc, sudoite, etc. Especially direct observation of the stacking disorder in kaolin group minerals was an epoch-making work in the history of this topic started more than a half century ago.Besides, several new techniques and ideas to characterize the structure (stacking sequence, crystal orientation, morphology, etc.) of fine-grained materials using Kikuchi patterns were developed and demonstrated. Less

在陆地表面有许多有趣的自然物质，它们是在温和的温度下富含水和氧化的条件下形成的。这些材料通常是非常细粒度的，不具有三维周期性，不像普通的晶体矿物。从这些特征来看，它们可称为“无机大分子”。然而，它们的原子结构和纹理还没有得到很好的理解，由于非常小的颗粒尺寸和非周期性结构。典型的例子是伊毛戈兰、蒙皂石和一些具有严重堆垛无序的层状硅酸盐。本研究的目的是发展新的方法和技术来研究这些材料，并阐明它们的结构和在地球上形成的条件。首先，我们试图从电子衍射图的强度分布确定伊毛戈兰石（一种天然纳米管）的原子结构。然而，一个完全解释电子相互作用的合理模型， ...更多信息没有得到n个图案。这项研究必须作为未来的研究继续进行。与此同时，AIST的Suzuki在寻找实验室合成条件方面取得了进展。蒙脱石是一种非常细粒度的层状硅酸盐，通常被认为是“纳米片”。它的基本结构是由两个四面体片和一个八面体片组成的2：1层状结构，但具体结构尚不清楚。特别讨论了2：1层中八面体比例的分布。我们研究了使用高分辨电子显微镜（HRTEM）确定阳离子分布的可能性。然而，发现在图像记录期间的强电子束使2：1层脱羟基，并且这种脱羟基诱导阳离子迁移。我们需要找到一个想法来克服这个问题在未来。另一方面，我们在一种云母--绿鳞石的热脱羟基相中发现了一种新的2：1层状结构，利用高分辨透射电镜和粉末X射线衍射图的模拟，我们在阐明各种层状硅酸盐的堆积无序的本质方面取得了大量的进展。所研究的层状硅酸盐包括高岭土类矿物、叶蜡石、滑石、苏铁等，特别是直接观察高岭土类矿物的堆积无序是半个多世纪前开始的一项划时代的工作，此外，还提出了一些表征层状硅酸盐结构（堆积顺序、晶体取向、形貌等）的新技术和新思想。开发并演示了使用菊池模式的细粒度材料的制造方法。少