The importance of timing. The working principle of an ordinary clock. The features of the U.S. Atomic Clock. The manufacturer of the U.S. Atomic Clock.
it gains only a second in a million years its deviation is within a second in a million years it loses only a second in a million years its deviation can never be detected
压力式滤油机停机时应先关闭油泵的进口阀门 Powered by Froala Editor 压力式滤油机停机时应先关闭油泵的出口阀门 Powered by Froala Editor 压力式滤油机停机时应先切断电源再关闭油泵的进口阀门 Powered by Froala Editor 压力式滤油机工作时应有专人看管 Powered by Froala Editor 压力式滤油机外壳应可靠接地 Powered by Froala Editor