flat sheet

基本解释

Graphene is a flat sheet of carbon just one atom thick – with the carbon atoms arranged in a honeycomb lattice.
石墨烯是一种只有单原子厚度的碳原子平面层——碳原子按蜂窝状晶格排列。
Such a material, Veselago determined, could form a superlens: a flat sheet capable of focusing light even better than curved lenses do.
维斯赖戈确定的这种的材料，可能形成一种完美透镜：一块平板，对光的聚焦效果比传统的曲面透镜更好。
The many dimensions of the globe, its curves and changing bumps, its shifting borders and evolving landscapes, cannot all be depicted accurately on a flat sheet of paper.
地球的多个维度、它的曲面和变化的凸起、不断演进的边界和地形，都无法在一张平展的纸上完全精准地描绘出来。

This tube, this hollow tube, which food passes through is made up of many, many epithelial cells which directly abut one another and would be a flat sheet except that it's rolled up into a tube.
这个管道,这个中空的管道,食物可以穿行其中,而它就是由许多许多上皮细胞构成的,上皮细胞一个连着一个,形成了一个平坦的细胞层,但实际上它们还在肠管中卷成管状
耶鲁公开课 - 生物医学工程探索课程节选

ADA2h has two helix-shaped structures called alpha helices that are packed against a flat, sheet-like structure.
ECONOMIST: Folding stuff
She laid him back down and walked around the bed, working the sheet until it lay reasonably flat.
NEWYORKER: The Visitor