His discoveries, which won him the Nobel prize, led to the caesium atomic clock and the hydrogen maser.

这一获得诺贝尔奖的发现产生了铯原子钟和氢微波激射器。

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Astrium's role, at its UK centre in Portsmouth, was to integrate all the payload components, including hydrogen-maser atomic clocks, the ultra-precise time-pieces on which Galileo's performance depends.

BBC: Galileo: Europe's version of GPS reaches key phase