凹形

They may be acuminate, rounded, conical, flat-topped, or umbilicated, and may appear white, red, yellowish, reddish brown, or black.

可以为尖形、圆形、圆锥状、平顶，或呈脐凹状。颜色可为白色、红色、淡黄色、淡红褐色或黑色。

The comparative experiments on the abrasion under unlubricated friction condition between the samples with smooth and coupling nonsmooth surfaces were performed by help of the experimental optimum design.

采用试验优化设计方法对相同试验条件下凹坑形仿生光滑试样以及具有仿生耦合表面的非光滑试样进行了干摩擦磨损试验对比研究。

The comparative experiments on the abrasion under unlubricated friction condition between the samples with smooth and coupling non-smooth surfaces were performed by help of the experimental optimum design.

采用试验优化设计方法对相同试验条件下凹坑形仿生光滑试样以及具有仿生耦合表面的非光滑试样进行了干摩擦磨损试验对比研究。

Sessile spikelet 3.5–4.5 mm, pallid; callus hairs 1/8 spikelet length; lower glume oblong-lanceolate, membranous, back slightly concave, villous except near apex, veinless between keels, upper keels smooth or pectinate-scabrid, apex narrowly truncate or 2-toothed; upper glume apex with 2–2.5 mm awn; upper lemma narrow, 2-toothed in upper 1/4; awn ca.

无梗小穗3.5-4.5毫米，灰白色；胼胝体毛1/8的小穗长度；长圆状披针形的下部的颖片，膜质，背稍凹，除近先端之外的具长柔毛，上面颖片先端具2-2.5毫米芒；在上面1/4里狭窄，2齿状的上面外稃；芒约1厘米，柱子具短缘毛。

This paper describes the concaved gear tooth profile after shaving resulting from the unbalance of cutting forces due to the variation of numbers of contact points acting on the teeth flanks, during backlash-free meshing engagement between the shaving cutter and the gear workpiece.

本文认为剃齿齿轮产生齿形中凹现象的主要原因是由于剃齿刀和齿轮在无侧隙紧密啮合过程中，因两侧齿面接触点数量的变化引起切削力的不平衡而造成的。

A high-strength steel pipe rockbolt has an expansive rockbolt main body prepared by processing a high-strength steel sheet of 1.8-2.3 mm in thickness with tensile strength of 490-640 N/mm 2 and elongation of 20% or more to a welded pipe and roll-forming the welded pipe to a shaped pipe having one or more concavities extending along an axial direction.

高强度钢管锚杆具有可膨胀锚杆主体，该主体通过下列步骤制成：将抗拉强度为490～640N/mm 2 ，伸长率为20％或更大，厚1.8～2.3mm的高强度钢板加工成焊接管，再将该焊接管滚轧成型成具有一个或多个沿轴向延伸的凹部的异形管。

Sedimentary basins vary from bowl-shaped to elongated troughs. Basins can be bounded by faults.

沉积盆地的形态可为盘状至纵长形凹槽；可以断层为界。

Culm sheaths brown-red when fresh, with sparse or rather dense small spots, distal margins dark purple

没有腺毛的花梗和萼片；种子肾形三角形，具凹槽 56

The relationship of spring back angle with bending clearance and die shoulder radius in the U-shaped bending of Aluminum alloy sheet was investigated.

主要研究了铝合金板材 U形弯曲回弹角与弯曲间隙、凹模入口圆弧半径之间的关系，分析了不同厚度的板材弯曲回弹角的差异。

A three-dimensional finite-element model, which includes plate, punch, die and holder pad, is established to simulate the drawing process based on the characteristics of the square box part.

根据方盒形件的特点，本文建立了包括板料、凸模、凹模以及压边圈在内的三维有限元分析模型。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。