铯射束时间标准 cesium atomic beam frequency standard: 铯原子射束的频率标准cesium standard: 铯钟cesium atomic-beam tube: 铯原子束管cesium beam atomic clock: 铯辐射原子钟cesium beam controlled oscillator: 铯束控制振荡器下载手机词典可随时随地查词查翻译