China on Saturday unveiled its top 10 national scientific advances of 2020. 

More than 3,200 experts from national academies and laboratories voted for 31 nominations from four scientific fields. Here are the 10 winners recognized at an event organized by China's Ministry of Science and Technology.

1. Chinese scientists' remarkable progress in tackling COVID-19 

Tackling the COVID-19 outbreak and preventing the viral transmission received overwhelming recognition. So far, China has approved four vaccines for conditional commercial use in the country and also donating it to other countries.

2. The Chang'e-5 probe's retrieval of lunar samples 

After 24 days of travel, Chang'e-5 mission concluded successfully, bringing back 1,731 grams of lunar samples. The probe landed in north China's Inner Mongolia Autonomous Region on December 17, 2020. The mission successfully completed China's current three-step lunar exploration program of orbiting, landing and bringing back samples. 

3. New descending record of China's deep-sea manned submersible 

The submersible, which name means "striver" in Chinese, dived to a record depth of 10,909 meters in the Mariana Trench on November 10, 2020, and returned after 18 days. The expedition team battled typhoons, heavy rains and high temperatures to conduct multiple tests and obtained a batch of sediment, rock and seabed biological samples. 

4. Research on the transmission of human genetic materials 

DNA replication is the basis for the precise transfer of human genetic material between cells. Inaccurate or incomplete DNA replication can lead to mutations in the genetic material in the progeny cells and may cause cancer. 

Chinese scientists have provided a new perspective for understanding DNA replication by revealing a regulatory mechanism mediated by a histone variant. The histone variant H2A.Z has been found to be able to regulate "the licensing and activation of early replication origins and maintains replication timing," the research team led by Li Guohong and Zhu Mingzhao from the Institute of Biophysics of Chinese Academy of Sciences (CAS) said in a report published in the journal Nature. 

The findings are significant in understanding many physiological processes such as growth and immune cell activation and also provide a theoretical basis for understanding cancer genesis and treatment. 

5. A new material with ultrahigh piezoelectricity 

Led by Professor Xu Zhuo, a team of researchers from Xi'an Jiaotong University has developed a new type of material which is transparent ferroelectric single crystal, called Sm-doped PMN-PT (Sm-PMN-PT) single crystals. 

By creating the new material, the team made a breakthrough in piezoelectric properties, which has been widely applied in ultrasonic imaging, sonar equipment and micro-electronics mechanical systems. 

This new material can greatly improve the imaging resolution of a photoacoustic imaging system in the diagnosis of breast cancer, melanoma and blood diseases, as well as provide new key material for the development of high-performance electro-optic modulator, optical phased array and quantum optical devices. 

6. Accurate measurement of Mount Qomolangma height

China started a new round of measurement of Mount Qomolangma's height in collaboration with Nepal last May. The research team from both countries accurately measured the mountain's height and announced that it's 8,848.86 meters tall. 

The team used measurement data from satellites, accurate leveling and snow-level radar technologies, marking a new technological breakthrough. 

Except for the geographic difficulties, the mountain is hard to measure because the height of the summit keeps changing as the mountain sits on two tectonic plates of the Earth. As the two plates keep slowly moving toward each other, the shape of the ground can change drastically. 

7. Revealing the evolution and migration history of Chinese populations with ancient DNA 

Researchers from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (CAS) reported in the journal Science online last May that they have retrieved DNA from 25 ancient human remains dating back 9,500 to 4,200 years and one dating back to 300 years from sites across China. 

The analysis of genomes sequences of the DNA revealed a significant episode of admixture of ancient humans in East Asia, suggesting that population movement played a profound role in the early genetic history of East Asians. They found that Early Neolithic East Asians were more genetically differentiated from each other than present-day East Asians are. 

8. Recreating the history of over 300 million years of biodiversity changes on Earth through big data 

A team of scientists based mostly in China has mined a database of more than 11,000 fossil species that lived from around 540 million to 250 million years ago by using the world's fourth most powerful supercomputer, Tianhe II. 

Fan Junxuan, a paleontologist at Nanjing University in China, led the team to create and analyze a database of fossil marine invertebrate species that were found in more than 3,000 layers of rock, mostly from China but representing geology across the planet during the early Palaeozoic. 

The effort revealed for how long, and in what order, all 11,000 species had existed. It took the supercomputer around seven million processor hours. It is published in Science on 17 January, 2020.

9. Biomarkers and potential intervention targets for organ aging in mammals 

The in-depth study on the aging problem and scientific actions to tackle it has become a pressing issue as a major percentage of the world's population is growing old.  

A study jointly conducted by researchers from the Institute of Zoology of CAS, Beijing Institute of Genomics and Peking University systematically revealed the new biological markers and anti-aging targets for multi-organ aging in mammals. The study also shed light on the scientific links among metabolic interventions, immune responses and lifespan. 

The findings have built up a crucial foundation for the early warning and scientific response to the aging problem and age-related diseases. 

10. Quantum interference in chemical reactions 

The essence of chemical reactions is impossible to be studied as the quantum mechanics phenomena in the reactions can hardly be observed directly.

Researchers from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences provided a research model, which helps in observing an oscillation caused by the quantum mechanical interference generated by two different pathways. 

This study reveals that quantum mechanics can be observed when the energy generated by the reaction is at a low level.