凹面

Meanwhile, the larger the relative aperture of the holographic concave grating on aspherical surface is.

同时，利用较大相对孔径非球面全息凹面光栅，可使平场光谱仪的结构更紧凑，从而可实现平场光谱仪的小型化。

Meanwhile, the larger the relative aperture of the holographic concave grating on aspherical surface is, the more compact the flat-field spectrograph will be.

同时，利用较大相对孔径非球面全息凹面光栅，可使平场光谱仪的结构更紧凑，从而可实现平场光谱仪的小型化。

Reynolds number of impingement, inclined jet angle, the ratio of the jet distance to the diameter of the jet hole and the relative curvature (the ratio of the diameter of jet hole to the diameter of concave surface) were changed to study the rules of flow structures varying with these parameters. At the same time, the developing and disappearing phenomena of the induced vortex were analyzed.

通过改变冲击雷诺数、冲击角度、相对冲击间距（冲击间距和冲击孔直径之比）以及相对曲率（冲击孔直径同凹面靶板直径之比）等参数，分析了受限空间中，斜向冲击曲率表面后产生的涡系结构及其发展和变化规律。

The ray tracing map of a concave grating ruled on toroidal surface proves the feasibility of the method.

通过刻划在非球面基坯上的凹面光栅验证了光线追迹方法的可靠性。

The surface polished by soft disk is easily to become concave surface under pressure. So soft disk is suitable for curve surface polish.

软盘抛光的抛光面，在石材受压时易屈服成一凹面，适用于弧面型抛光。

This paper presents the principle, structure and aberration-corrected designing of a flat focal field concave grating spectrograph.

介绍了用于 X光能谱测量研究的平焦场凹面光栅光谱仪的原理、结构及象差校正的设计方法。

A molded plastic bottle (10) has a base (24) having an outside surface rotationally symmetric about a longitudinal axis of the bottle including a convex heel (26) and a central concavity (28) separated by a standing ring (30) supporting the bottle on an underlying surface.

一种模制的塑料瓶(10)，具有一个带有绕瓶子的纵轴转动对称的外表面的底座(24)，该底座包括凸出的跟部(26)和中心凹面(28)，它们用将瓶子支撑在任何下垫面上的立环(30)互相分开。

Seed cones borne in groups of 1-6, globose or subglobose, 0.9-1.6(-2.5)× 1-2(-2.5) cm; cone scales 20-30, proximal 2 margins often convex in outline, or all 4 margins ± concave in outline, middle part with or without distinct shoulders at widest point, apex usually recurved, umbo rhombic, distally with 4 or 5(-7) toothlike projections 1-3.5 mm. Seeds 2-5 per cone scale, brown or dark brown, irregularly ellipsoid or multiangular and ± compressed, 4-6.5 × 2-3.5 mm; wings 0.2-0.25 mm wide.

1-6个中的成群忍受的球果，球状或近球状， 0.9-1.6(-2.5)* 1-2(-2.5)厘米；珠鳞20-30，轮廓的下部的2个边缘通常凸面，轮廓的或全部4个边缘多少凹面，有或没有在宽点的离生的肩的中部，先端通常下弯，鳞脐，上部每珠鳞具4或5(-7)种子2-5 1-3.5毫米的齿状预测， 4-6.5 * 2-3.5 毫米；翅0.2-0.25毫米宽。

If the dial indicator reads 0.14~0.3mm , it means the tooth clearance is right; You can also use a 15~20mm long and 0.5mm thick lead sheet or "∽"-shaped fuse . Put the sheet or fuse between the unengaged tooth flanks tha is between the convex surface of small bevel gear and the concave surface of the large bevel gear. Turn the gear, then the pressed thickness of the big lead sheet end suggests the normal tooth clearance of this site.

另一种方法是用长15~20毫米，厚0.5毫米的铅片或弯成"∽"形的保险丝，放入两齿轮非啮合的齿面之间（即小锥齿轮的凸面和大锥齿轮的凹面之间），转动齿轮，则铅片在靠近大端处被挤压的厚度即为该处的法向齿侧间隙。

Diurnal variation of the upper and lower tear menisci occur.

上下泪河凹面存在着昼夜变化。

Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。