What type of neck is under the head of a carriage bolts, a step bolt and an elevator bolt ?

马车螺栓，阶梯螺栓和电梯螺栓的颈是什么形状？

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An improved method of stress analysis about bolt screw with interference fitting is provided as the first step of fatigue life-prediction for the joint.

针对过盈螺纹的疲劳寿命估算进行了工作，求解应力是寿命估算的第一步。

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In the second step, the prestressed cable is used as reinforced support to the roof plate, and the reinforcement by bolting and grouting with inside grouting bolt is applied to base Angle.

然后再采用预应力锚索对顶板进行加强支护，且对巷道底角采用内注浆锚杆进行锚注加固。

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He can take another step in that direction Saturday when the Jamaican four-by-100 relay team is expected to give Bolt a chance for his sixth straight gold.

VOA: standard.2009.08.21

For Blake, who recorded the year's leading time over 200m and a personal best in Friday's 100m, it marks another significant step in his rise to prominence after clinching World Championship 100m gold in Daegu, South Korea last year, after Bolt was disqualified from the final after a false start.

CNN: Lightning strikes twice as Blake beats Bolt again