几十年来，粒子物理学家们用氢原子作为基准衡量质子的大小。

For decades, particle physicists have used the hydrogen atom as a benchmark for measuring the size of protons, which are part of the core of atoms.

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这就是众所周知的铯原子钟的基础，它是目前的频率和时间基准。

This is the basis for the well - known cesium clock, presently the standard of frequency and time.

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原子频标是空间技术和授时系统的频率与时间基准，直接决定了卫星通信的质量。

Atomic frequency Standard is the frequency and time benchmark of space technology and time awarding system, directly determining the quality of satellite communications.

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