Rolling theoretical rotation axis line of the inner ring to the center axis line of bearings, thrust bearings on the shaft circle refers to the axis line.

滚动轴承的理论旋转轴心线，对向心轴承即内圈轴心线，对推力轴承则指轴圈轴心线。

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This paper also presents a method to solve the tunnel axis displacement on line caused by angle error between tube center axis and datum of joint.

分析了对接面与管段中心线夹角误差对沉放后线路位置的影响，提出了控制隧道轴线偏差的措施；

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Xuan Sefa a cone-shaped pieces of the hoist and around the center line perpendicular to the axis of rotation pipeline, completed the hoist valve action.

的启闭件呈锥形，并绕垂直于管道中心线的轴线旋转，完成阀门的启闭动作。

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