凹曲线 meaning in English

sag vertical curve; concave curve; notching curve
◇凹曲线饰 hypophyge

2 % 22 % and 29 % respectively less than using other three knives at cutting speed of 500mm / min when the moisture contents of rootstalks was 48 . 2 % . the cutting forces were tested at four different parts of rootstalk that were the middle part along a radius , the tip part along a radius , the middle part along axis and the stalk part along a radius , and the force at the middle along a radius is the largest and increase 32 % 45 % 111 % , respectively more than at the other three parts . the force increase 37 % to cut the rootstalks from the areas one crop a year more than that from two crops a year
试验结果表明，根茬含水率愈高，剪切力愈小，根茬含水率与剪切力近似为二次曲线关系；刀片剪切速度愈快，剪切力愈小；凸曲线、斜线、凹曲线和直线四种不同的刀刃曲线对整株根茬剪切力依此由小到大，凸曲线和斜线剪切时有一定程度的滑切作用，所以剪切力相比较小，当根茬含水率为48 . 2 ，剪切速度500mm min时，与其他三种曲线相比凸曲线型刀刃的剪切力依次分别减少了7 . 2 、 22和29 ；对根茬中部、梢部和根部的剪切力，在相同试验条件下，径向中部最大，比梢部，轴向根部和根部茎秆所需剪切力分别增加32 、 45和111 ；当含水率为48 . 2 ，刀片的剪切速度为500mm min时，一年一熟玉米根茬比一年两熟的玉米根茬剪切力增大37 。