Core Viewpoint - The NIM-Sr1 strontium atomic optical lattice clock developed by the China National Institute of Metrology has been approved to calibrate International Standard Time, marking a significant milestone in China's optical clock research and enhancing its influence in the international time frequency research field [1][2]. Group 1 - The NIM-Sr1 clock can achieve precision of several billion to over a hundred billion years without losing a second, which is set to replace cesium atomic clocks in redefining the time measurement unit "second" [1]. - The International Bureau of Weights and Measures has published calibration data for the NIM-Sr1 clock, confirming its compliance with the rigorous standards set by the International Time Frequency Committee [2]. - The approval of NIM-Sr1 and the new cesium fountain clock NIM6 signifies a major leap for the China National Institute of Metrology, transitioning from a "single-core traction" to a "three-engine drive" model in calibrating international standard time [2]. Group 2 - The three clocks (NIM-Sr1, NIM5, and NIM6) enable China to demonstrate its commitment to international atomic time cooperation while also maintaining the ability to independently calibrate its standard time, ensuring the security and controllability of its time frequency system [2]. - This advancement supports the robust development of quantum technology and the quantum industry in China [2].