对于床身长度大于8m的机床调整水平时,可先经过“自然调平”,使导轨的偏差调至允许偏差两倍的范围内,而后可借助紧固地脚螺栓等方法强制机床达到精度的要求。
参考答案:对
—How old are you?
—I was born ______ September 5, 1990. [ ]
A. in
B. on
C. at
D. from
计算题:已知某钢管直径为60mm,弯曲后最大直径为61mm,最小直径为59.5mm,试求椭圆度为多少?