BEIJING, Jan. 18 -- China leads development of satellite atomic clocks, researchers said Thursday.
BeiDou navigation satellites sent to orbit last week are fitted with the latest generation of rubidium and hydrogen atomic clocks developed by the Second Academy of China Aerospace Science and Industry Corp.
Compared with the previous generation, the new clocks are smaller, lighter, perform much better and are among the world's best, Chinese scientists said.
Atomic clocks use vibrations of atoms to measure time. An accurate and ultra-stable set of atomic clocks is essential for global navigation satellite systems that require a high degree of precision.
BeiDou aims to rival the GPS of the United States, Russia's GLONASS and the European Union's Galileo as an alternative global satellite navigation system. It intends to cover Belt and Road countries by the end of 2018 and operate globally by around 2020 with a 35-satellite constellation.
八年级英语用词的适当形式填空
中考英语精选真题讲解
九年级英语上完成句子专项练习
中考英语短文填空练习一
中考英语短文填空练习二
八年级英语宾语从句练习
英语语法大全整本收录(五)动词
八年级英语上单选专项练习一
英语宾语从句专题复习
英语中考语法(四)数词专题复习
八年级英语同义句转换
九年级英语上词汇专项练习
英语中考语法(六)连词专题复习
九年级英语完成句子专项练习
九年级英语上单选100免费下
初中英语常用量词词组及其它词组
八年级英语同义句转换练习
英语语法大全整本收录(四)形容词和副词
从词法和句法入手巧解短文改错题
击重点句式链接中考考点(一)
英语语法大全整本收录(七) 动词不定式
点击重点句式链接中考考点(三)
八年级英语单项选择专项练习一
初中教材中的八个IT句型
八年级英语上重点词组练习
九年级英语单选练习50
八年级英语上单选专项练习二
九年级英语上完型填空练习七则
英语中考语法(五)动词专题复习(1)
中考英语词汇练习前三册
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |