Chevron Layer Structure and Parabolic Focal Conics in Smectic A Liquid Crystals
Chevron Layer Structure and Parabolic Focal Conics in Smectic A Liquid Crystals
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近晶A液晶中的V形层结构和抛物线焦锥
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
A. Fukuda
中科院分区：
文献类型：
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作者：
Y. Ouchi;Y. Takanishi;H. Takezoe;A. Fukuda
用X射线衍射分析研究了均匀取向的8 CB和40.8液晶的近晶A层结构。它已被证实，均匀排列的SmA细胞的特征往往是由人字形层结构与细长的抛物线焦锥阵列或由倾斜的层结构与起伏图案纹理。这种行为是由层变薄引起的，并且通常受到电池厚度的影响。人字形结构的层倾斜角通常取决于相序列和热历史;例如，当均匀取向的40.8单元从SmA相冷却到SmB相时，加热过程中SmA相中的层倾斜角变为冷却过程中的层倾斜角的两倍。
The smectic A layer structures of homogeneously aligned 8CB and 4O.8 liquid crystals have been studied by X-ray diffraction analysis. It has been confirmed that the homogeneously aligned SmA cell is frequently characterized by the chevron layer structure with an array of elongated parabolic focal conics or by the tilted layer structure with the undulation pattern texture. This behavior is caused by the layer thinning and is generally affected by the cell thickness. The layer tilt angle of the chevron structure often depends on a phase sequence and a thermal history; for example, when a homogeneously aligned 4O.8 cell has cooled down to a SmB phase from a SmA phase, the layer tilt angle in the SmA phase in the heating process becomes two times larger than that in the cooling process.