With the constant increase of the trains' speed, the aerodynamic noise gradually succeeds the traditional tracknoise and becomes the main noise source of the high-speed trains.
随列车行驶速度逐年提高，气动噪声源逐渐超越轮轨噪声成为高速列车最主要噪声源。
2
And watched three-spined stickleback fish hunt water fleas, to the accompaniment of either white noise calibrated to match the noise level of speedboats or a silent track as a control.
并控制三刺鱼在跟快艇噪音程度相当的白噪声中，或者完全安静的环境之下，观察它们捕食水蚤的情况。
3
Stackingimproved the signal-to-noise ratio and enabled the researchers to moreclearly track the path and behaviour of each unique signal as it passedthrough the lunar interior.