Chinese scientist pioneers world-leading cryogenic measuring method

Chinese scientist Gao Bo and her team at the Chinese Academy of Sciences (CAS) have developed a world-leading cryogenic measuring method that provides unprecedented accuracy for measuring extreme cold.

Known as Single-Pressure Refractive Index Gas Thermometry (SPRIGT), the new method determines thermodynamic temperatures with uncertainties as low as 0.25 mK in the 5 K to 25 K range.

"Cryogenic temperatures are those below 120 K, or minus 153.15 degrees Celsius. But our research focuses on even lower temperatures, below 24.5561 K, or minus 248.5939 degrees Celsius. The measurement technology of this temperature range provides critical support for areas such as frontier science, large-scale scientific facilities, deep-space exploration and green energy," Gao explained.

For nearly a century, China has no primary standard in this range. In 2019, the International System of Units was revised, changing scientific measurement definitions. Gao seized this historic opportunity. "Establishing China's cryogenic primary thermometry and solving frontier challenges is both a national demand and an opportunity of the era. As scientific researchers of the CAS, we deeply understand our responsibility and mission," Gao said.

In plain language, the new method is to hold the gas pressure steady, measure how much the microwave bends as it passes through the gas, and you get the temperature -- since the bending shifts with temperature.

The unit that Gao's team built in collaboration with France's national metrology institute (LNE-Cnam) can stabilize temperature to one 100,000th of a kelvin, control pressure to one 10‑millionth and measure microwave frequency to one billionth.

Recognizing that uniting global scientific efforts is the most effective way to advance international cryogenic metrology, Gao elevated the Sino‑French cryogenic metrology joint laboratory to an intergovernmental lab. The cryostats she led the development of were exported to France to support its primary pressure standard research.

"We're pushing forward to set up an international cryogenic organization and preparing to launch an international journal on cryogenics," Gao said.

Chinese scientist pioneers world-leading cryogenic measuring method

A large number of rescuers are racing against time to save survivors from the rubble in La Guaira state, the worst-hit region by the two powerful earthquakes that struck Venezuela on Wednesday.

The twin quakes, measuring magnitude 7.2 and 7.5, struck central Venezuela less than a minute apart on Wednesday, according to the U.S. Geological Survey (USGS).

Venezuelan National Assembly President Jorge Rodriguez said Saturday that the death toll from the quakes had risen to 1,430, with 3,238 people injured and 3,142 families affected by the disaster.

La Guaira has been placed under military control. Access roads to the coastal state have been strictly restricted to emergency vehicles only, with civilian traffic barred to ensure unimpeded passage for rescue convoys, military trucks, and volunteer aid groups.

In one of the most dramatic scenes of destruction, an eight-story hotel with over 100 guest rooms in La Guaira has almost entirely collapsed, with only the entrance structure standing amid the debris.

Heavy machinery and a large number of rescuers are working at the site, where an estimated 20 to 30 people are believed to be trapped beneath the ruins -- most of them hotel staff.

"We estimate that 20 to 30 people are still trapped under the rubble. The number is significant. We also need to recover the deceased as quickly as possible," said a local official.

Authorities have called on the public to avoid traveling to the disaster zone to prevent clogging rescue routes, which are vital for delivering supplies and transferring the wounded to hospitals.

Rescuers race against time to save lives in Venezuela's La Guaira after devastating earthquake