a concave lens/mirror
凹透镜；凹镜
1.凹的,凹面的
1.凹,凹线,凹面(物)
1.把...弄成凹(面)
1.curved inward
1.the top of the plastic hat is provided with a ball-shaped concave position, where a press plate and a forcing screw are installed in.
塑制帽的顶部塑有球形凹进处、并可安装压板和压紧螺钉。
2.The head has a well-developed but compaction of the sarcoma, eyes and mouth within a concave in the sarcoma.
头部有着发达而又紧实的肉瘤，眼睛和嘴凹在肉瘤内。
3.Take out a piece of A in A letters along the diagonal nail row, by a concave-convex feeling.
拿出一张A在A的字母上顺着斜线用指甲一划，就由凹凸感了。
4.The time of purchase can be overturned bottom of the pot, pan with your fingers to withstand concave center, with a hard object percussion.
在购买时可以推翻底部的锅，锅用手指承受凹中心，用硬物敲击。
5.It may be flat, concave, and convex or any one of a great variety of shapes to promote turbulence or help control combustion.
其表面可能为平面、凹面、凸面或任何一种形状，其能促进气缸内涡流运动或有助控制燃烧。
6.At least one loop of absorption blind hole is evenly distributed around the segmental concave cavity along the radial direction of plane.
径向面上沿圆缺凹腔周围均匀分布不少于一圈的吸收盲孔；
7.typing, curling, concave design make brush head keep closer to eyes and make it easy to apply mascara onto tiny eyelashes on eye corner.
强效定型，卷翘，凹面刷头更加贴合眼部轮廓，更易于眼角细小睫毛的涂抹；
8.The bottom of the body designed no concave nest. So have lower flowing resistance and prevent valves leakage or damage from trash pipe up.
阀体底部设计无凹槽，球阀因此具有流阻小，阀体防止污物堆积造成阀门渗漏或损坏等特点。
9.A percussion instrument consisting of a concave brass plate that makes a loud clashing tone when hit with a drumstick or when used in pairs.
钹一种打击乐器，由一个凹铜片构成，当用单个或者双个鼓槌敲击时，可发出高的撞击声
10.In this paper, we investigate the natural boundary element method for an anisotropic problem in an infinite domain with a concave angle.
本文研究无穷凹角区域上一类各向异性问题的自然边界元法。