heptagons
n. 七角形;[数] 七边形
例句
The results show that the different arrangements of pentagons and heptagons along the axis cause obvious differences on the electrical properties of the carbon nanotube.
结果表明,拓扑缺陷五边形和七边形在碳管中沿轴向的不同分布对碳管电学性能的影响明显不同。