Analyses of Phase Transition by Coulomb Crystals in Fine-Particle Plamas

细颗粒等离子体中库仑晶体的相变分析

基本信息

批准号：
11680485
负责人：
HAYASHI Yasuaki
金额：
$ 2.3万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

In order to analyze the three-dimensional structure of three-dimensional Coulomb crystals, blue argon-ion-laser light (488nm) and red diode-laser light (690nm), which was expanded by a cylindrical lens perpendicular to an re electrode, were irradiated at the same time to fine-particles, and top views were obtained by the blue light and side views by the red light through a optical filter of the color. By the observation of top and side views at the same time and at the same position using this method, accurate analyses have become possible. The analysis of transition process of Coulomb crystal structures has become also possible every 1/30 seconds.Using these analytical methods, we observed, in three-dimensional Coulomb crystals, body-centered-cubic (bcc)-like structures (011) or (001) planes parallel to the electrode, face-centered-cubic (fcc)-like structures (111) planes parallel, and hexagonal-close-packed-like structures (0001) parallel. The ratio among three lattice constants for the bcc-like structure was 1 : 1.56 : 1.53, which shows that the crystal should be called the body-centered-tetragonal (bct) lattice. For the fcc-like structure, the ratio of the lattice constant in the close-packed plane to the distance between the neighboring planes was 1 : 0.83, which is very close to the ratio for fcc lattice. The coexistence of fcc and bct structures and the transition between the two structures were observed and analyzed. From the results, it was confirmed that the structural change occurred by the slip in crystal planes between fcc (111) and bct (001) to the direction of fcc [110] and bct [111]. The transition corresponds to the martensitic transformation of carbon steel.

为了分析三维库仑晶体的三维结构，通过垂直于电极的柱面透镜放大后的蓝色氩离子激光（488nm）和红色二极管激光（690nm）被同时照射微粒子，通过该颜色的光学滤光片，用蓝光获得顶视图，用红光获得侧视图。通过使用该方法同时在同一位置观察俯视图和侧视图，可以进行准确的分析。每1/30秒对库仑晶体结构的转变过程的分析也成为可能。利用这些分析方法，我们在三维库仑晶体中观察到类体心立方（bcc）结构（011）或（ 001) 平行于电极的平面、类面心立方 (fcc) 结构 (111) 平行的平面和类六方密堆积结构 (0001) 平行线。类bcc结构的三个晶格常数之比为1：1.56：1.53，这表明该晶体应称为体心四方（bct）晶格。对于类fcc结构，密排面内的晶格常数与相邻面之间的距离之比为1:0.83，这与fcc晶格的比率非常接近。观察并分析了fcc和bct结构的共存以及两种结构之间的转变。结果证实，fcc(111)和bct(001)之间的晶面向fcc[110]和bct[111]方向滑移而发生结构变化。该转变对应于碳钢的马氏体转变。