The recent launch of regular high-speed train connecting Belgrade and Subotica in Serbia, an important project under China's Belt and Road Initiative, has significantly enhanced travel efficiency by drastically cutting travel time, advancing infrastructure connectivity between China and Serbia.
Officially opened on October 8, the railway marks the full operation of Serbia's first 200-km-per-hour railway line.
Operated by the national rail company Srbijavoz, the 183.1-kilometer Serbian section of the Hungary-Serbia railway connects the capital to the north, reducing travel time from six-and-a-half hours to approximately 80 minutes.
Construction of the project began in 2017, with the first phase connecting Belgrade to Novi Sad, which is roughly halfway to Subotica, opening in 2022.
At the peak of construction, over 4,000 Chinese and Serbian workers collaborated on the project.
"Chinese experts have learned to adapt to European standards and familiarize themselves with European certificates. On the other hand, Serbian engineers became familiar with Chinese technical equipment and design concepts and were able to apply globalized principles in construction," said Duan Wei, deputy chief engineer of a joint venture of the China Railway Construction Corporation (CRCC) and CCCC.
Built by China Railway International and China Communications Construction Company (CCCC), the railway is expected to spur tourism, attract investment, and strengthen regional connectivity.
The Hungarian section of the Hungary-Serbia railway, which spans 341.7 kilometers, is expected to open next year.
New Serbia rail link accelerates travel, deepens Belt and Road cooperation
Researchers from the University of Science and Technology of China have achieved a major breakthrough in optical clock technology, developing a strontium optical lattice clock with stability and uncertainty both surpassing the 10⁻¹⁹ level, meaning the clock would lose or gain less than one second over roughly 30 billion years.
The findings were published in the international metrology journal Metrologia on Thursday.
Optical clocks are considered the most precise timekeeping devices currently available. They measure time by using the frequency of light emitted when electrons transition between energy levels in atoms. They can directly support the redefinition of the second in the International System of Units.
"This breakthrough enables China to rank among the top in the world in the development of optical clocks. It also provides a feasible technical path for the development of transportable optical clocks and satellite-borne optical clocks, and lays a solid and reliable foundation for using optical clock technology in areas such as testing fundamental laws of physics, supporting next-generation satellite navigation systems, and establishing a globally unified ultra-high-precision time reference," said Dai Hanning, professor of the university.
Beyond time-keeping, optical clocks can provide highly accurate time references for modern technologies such as satellite navigation, telecommunications and precision measurements. They also offer new experimental platforms for testing fundamental physics, including general relativity, as well as for the detection of gravitational waves and dark matter.
Achieving both stability and uncertainty at the 10⁻¹⁹ level opens the door to a range of frontier applications. These include millimeter-level measurements of gravitational potential and altitude, which could help monitor crustal deformation, groundwater changes and volcanic activity, as well as improve geoid mapping for disaster prevention and resource exploration.
Chinese optical clock accurate to within 1 second over 30 bln years
Chinese researchers develop world's most precise optical clock
