It can maintain a fluid interface at a reference line in an inclined glass tube . 它能保持流体分界面在倾斜的玻璃管中基准线上。
The gyro vertical utilizes a gyroscope as an integrating device to obtain the average position of a pendulous gravity reference . 垂直陀螺利用一个陀螺仪作为积分装置以得摇摆不定的重力基准线的平均位置。
Building hardware ; hinges for doors ; reference - lines for hinges 建筑五金件.门折页.折页基准线
A line of punch positions parallel to the y datum line of a punch card 和卡片的y基准线平行的一行穿孔位置。