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Atomic clocks are the most accurate time and frequency standards. They use vibrations of atoms to measure time. An accurate and ultra-stable set of atomic clocks is essential for global navigation satellite systems.

He expressed the hope that scientists from different countries can make full use of the alliance as a platform to carry out major science and technology cooperations, foster more talented people in innovation and entrepreneurship and enhance innovative ability in science and technology.

"China's past achievements were realized by the reform and opening up, and future progress can only be made by further reform and opening up," he said.

Saying China's economy has maintained overall stability and steady progress, Xi noted that the goal of "making people well-off" pushes the important potential for the country to achieve further growth.

Calling the U.N. a symbol of multilateralism, Wang stressed that all parties should adhere to international rules such as the purposes and principles of the U.N. Charter to maintain the healthy development of multilateralism.