Kingfishers wedge themselves into water with a streamlined beak that gradually increases in diameter from tip to head, letting water flow past.

翠鸟流线型的长喙从尖端到头部的直径是逐渐增大的，潜水时会让水流向身后。

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Top view of fillister head screw. Selection box represents thread diameter.

槽头螺钉的俯视图。选择框代表螺纹直径。

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Top view of slotted head set screw. Selection box represents thread diameter.

一字槽头螺钉的俯视图。选择框代表螺纹直径。

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The students' effort had a head diameter of 88.9 cm (35 in) and a shaft width of 35.24 cm (13.87 in).

CNN: February 5, 2013 -- Updated 1840 GMT (0240 HKT)

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued new advice saying patients with these large head diameter metal-on-metal hips will need monitoring for the life-time of the implant.

BBC: Annual checks for patients with all-metal hips

But concern has been emerging for some time about certain types of metal-on-metal hips, in particular those where the ball head has a diameter of 36mm or more.

BBC: Annual checks for patients with all-metal hips