得出了各地震台台基的脉动噪声的均方根值、观测动态范围、地噪声功率谱。

The article calculates the mean square root values of pulse noise, observational dynamic range and power spectrum of ground noise of all seismic station bases.

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因此，双螺杆压缩机与蜗杆压缩机相比，在相同转速下单位内排气次数少，气流脉动大，气流噪声大。

Therefore, double screw compressor and worm compressor compared, in the same speed of the units inside less number of exhaust air ripple, big air flow noise.

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研究表明，低马赫数情况下叶轮离散噪声主要是由脉动力造成，为降低低马赫数下的叶轮离散噪声提供了参考。

Results show that under small Mach number the main source of discrete noise is the fluctuating force, which gives a guide for cutting discrete noise down.

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