For interval repeats, he runs 12 x 400 meters or 6 x 800 meters at slightly faster than his 5-K race pace.

在平时的间隔训练中，他用比5-K比赛速度稍快的速度跑12个400米或6个800米。

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Or it's 1/2 k x squared.

或者是1/2，k，x的平方。

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Materials and Methods K-value is defined based on 1000 cases of high frequency X-ray images to improve image quality by means of compressing or enlarging image grey.

材料与方法选取1000例高频X线片，针对X线图像选取不同的K值，以达到压缩灰度或扩展灰度，改善图像质量。

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