Adhere to the "four aspects" and concentrate on basic research
Interpretation of the Top Ten Progress of Chinese Science in 2022 (Self-reliance and Self-improvement in Science and Technology)
On March 3, the High-tech Research and Development Center of the Ministry of Science and Technology (Basic Research Management Center of the Ministry of Science and Technology) released the top ten advances in Chinese science in 17, including: Zhurong patrol radar reveals the superficial hierarchical structure of the Martian utopian plain; FAST finely depicts active repetitive fast radio bursts; The new principle realizes direct electrolysis of seawater to produce hydrogen; Reveal the mutational characteristics and immune escape mechanism of the new coronavirus; Achieve high-efficiency all-perovskite tandem solar cells and modules; The new principle switching device provides a new solution for high-performance mass storage; Quantum coherent synthesis of ultracold three-atom molecules; Ethylene glycol synthesis under mild pressure conditions; Discover the new mechanism of micro-nanostructure induced by femtosecond lasers in complex systems. Experiments confirm the superconducting state "segmented Fermi surface".
Adhering to the "four aspects" and concentrating on basic research, experts and scholars interpreted the scientific significance and potential application value of the ten major advances.
Zhurong's roving radar reveals the superficial layered structure of the Martian Utopia Plain
Su Yan, researcher at the National Astronomical Observatory of the Chinese Academy of Sciences:
On May 2021, 5, China's "Tianwen-15" first Mars exploration mission "Zhurong" rover successfully landed in the Utopia Plain. The Utopian Plain is Mars' largest impact basin, located in the northern hemisphere of Mars, its diameter is about 3300 kilometers, and it may have been a huge ancient ocean. The teams of Chen Ling and Zhang Jinhai of the Institute of Geology and Geophysics of the Chinese Academy of Sciences used the scientific detection data of the scientific payload ground penetrating radar carried by the rover to make breakthroughs. The ground penetrating radar uses the characteristics that electromagnetic waves can penetrate matter, and makes high-precision CT scanning of the Martian underground structure, and for the first time obtains a finely layered image of 1171 meters in the southern part of the Utopian Plain within 80 meters of the underground depth, and finds that there are three layers of structure in the shallow layer: the first layer is 10 meters of Martian soil, and the other two layers are 10-30 meters, 30-80 meters with the depth of the material from fine to thick layered structure.
The analysis showed that no evidence of the presence of liquid water from 0-80 meters was found in the landing area, but the possibility of the presence of salt ice was not ruled out. This study provides observational evidence of long-term water activity on Mars, reveals the changes of Mars from wet to dry, and lays an important foundation for in-depth understanding of Mars' geological evolution and environmental and climate changes.
FAST depicts active, repetitive fast radio bursts in fine detail
Professor Feng Hua of Tsinghua University:
Fast radio bursts (FRBs) are one of the most violent bursts in the cosmic radio band. Its duration is very short (about one millisecond), the intensity is very low, the observation and research are very difficult, and it is one of the major hot frontiers in the field of astrophysics research.
The team of Li Jing and Li Kejia of the National Astronomical Observatory of the Chinese Academy of Sciences used the 500-meter aperture spherical radio telescope FAST to discover the world's first continuously active fast radio burst FRB20190520B, which has the largest known environmental electron density and effectively promotes the multi-band research of FRB. By monitoring active repetitive FRB20201124A, the research team obtained the largest FRB polarization sample to date, and detected the magnetic field changes in the FRB local environment and its frequency-dependent polarization oscillation. In view of the active repetitive bursts, international cooperation was organized, especially the GBT and FAST observations of the large telescope in the United States, and the single parameter describing the surrounding environment of FRB, namely "RM diffusion", was revealed, and a unified mechanism for the polarization frequency evolution of repeated fast radio bursts was proposed.
The study finely depicts active, repetitive fast radio bursts and constructs a unified picture that can be called a "textbook-level discovery", laying the groundwork for finally revealing the origin of fast radio bursts.
The new principle realizes direct electrolysis of seawater to produce hydrogen
Zhang Jianling, researcher at the Institute of Chemistry, Chinese Academy of Sciences:
Hydrogen energy is regarded as the most promising clean energy in the 21st century, and hydrogen production by electrolysis of water is considered to be a clean and efficient method. The current electrolysis of water hydrogen production technology is based on the principle of freshwater electrolysis, and it is of great significance to use seawater to directly realize the electrolysis of water to produce hydrogen.
However, the composition of seawater is very complex, in addition to containing about 96.5% of water, it also contains various inorganic substances, organic matter, solid particles, microorganisms and other impurities, which makes seawater electrolysis produce a series of problems. Therefore, the existing electrolysis of seawater hydrogen production technology generally requires desalination of seawater first, and then electrolysis hydrogen production. By combining physical and mechanical processes such as molecular diffusion and interfacial phase equilibrium with electrochemical reactions, the team of Xie Heping of Shenzhen University/Sichuan University created a new principle and technology of in-situ direct electrolysis of seawater hydrogen production, established a theoretical method of direct electrolysis of seawater by self-migration and self-drive of gas-liquid interface phase transition, formed a mechanical driving mechanism of spontaneous phase change mass transfer of seawater with interfacial pressure difference, and realized the dynamic self-regulating and stable direct electrolysis of seawater hydrogen production by electrochemical reaction with seawater migration without additional energy consumption. The research has formed a zero-carbon hydrogen energy development path from the principle of originality, breakthrough technology, localized equipment to the characteristic electrolysis hydrogen production industry model, and the application value is huge.
Reveal the mutation characteristics of the new coronavirus and the immune escape mechanism
Yan Jinghua, researcher at the Institute of Microbiology, Chinese Academy of Sciences:
Will human infection with Omicron develop herd immunity and block the next round of infection? Can you predict the next pandemic?
The team of Cao Yunlong, Xie Xiaoliang and Wang Xiangxi took the lead in revealing the humoral immune escape mechanism and mutation evolution characteristics of the new crown Omicron mutant strain and its new subclass, revealing the escape mechanism of Omicron BA.1 neutralizing antibody and its relationship with the structural characteristics of the viral spike protein. BA.4 mutation can escape the neutralizing antibody produced after human infection with BA.5, which proves that it is difficult to achieve herd immunity through Omicron infection to block the spread of the new crown; based on the self-developed high-throughput mutation scanning technology, the immune escape mutation site of the new coronavirus receptor-binding domain was successfully predicted, and the broad-spectrum new crown neutralizing antibody was prospectively screened.
The research has deepened people's understanding of the new crown virus and humoral immunity, not only providing an important data reference for the adjustment of the research and development direction of broad-spectrum new crown vaccines and antibody drugs, but also actively promoting the development of science and technology in this field.
Achieve high-efficiency all-perovskite tandem solar cells and modules
Hu Jinsong, researcher at the Institute of Chemistry, Chinese Academy of Sciences:
Perovskite solar cells are a device that uses light-absorbing materials with perovskite structures to convert sunlight into electricity. At present, the photoelectric conversion efficiency of single-junction perovskite cells has reached 25.7%. Close to the theoretical efficiency of 31%, the theoretical efficiency of constructing tandem solar cells can reach about 45%. All-perovskite tandem solar cells have the advantage of low-cost solution phase treatment and show broad prospects in large-scale applications. The key bottlenecks include: in basic research, narrow bandgap perovskite grain surface defect density is high, which restricts the improvement of efficiency; In terms of industrial application, the preparation technology of large-area modules is still immature.
Tan Hairen's team at Nanjing University found that designing the polarity of passivation molecules can significantly enhance the defect passivation effect and greatly improve the efficiency of all-perovskite tandem cells. After testing, the efficiency of tandem cells reached 26.4%, setting a new efficiency record for perovskite cells and surpassing single-junction perovskite cells for the first time. On this basis, the team developed a mass-producible preparation technology for large-area all-perovskite tandem photovoltaic modules, using a dense semiconductor conformal layer to block the contact between perovskites and metal back electrodes in the module interconnection area, which significantly improved the photovoltaic performance and stability of the modules, and the research has broad development prospects.
New principle switching devices provide a new solution for high-performance mass storage
Professor Zhang Xing of Peking University:
High-density and massive storage are the key bottlenecks in the development of information technology and digital economy in the era of big data. In recent years, new memory technologies have made great progress, and most of these memories require a bidirectional threshold switching device to override the state as a storage carrier material, so as to realize the storage of information. Now commonly used bidirectional threshold switch devices are basically multi-material systems, components contain a variety of elements, one is that it is difficult to prepare atomic-level uniform materials on 12-inch silicon wafers, and the other is that such multiphase materials are also easy to separate phases, resulting in shortened life of switching devices. Therefore, the search for high-performance switching devices has become the key in the development of new memory.
The new switching device based on the interface effect of elemental tellurium and titanium nitride electrode invented by the team of Song Zhitang and Zhu Min of Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, gives full play to the unique advantages of fast tellurium melting-crystallization speed and low power consumption in the nanoscale two-dimensional limited structure, and the components are simple, which can overcome the problem of component segregation caused by complex components of bidirectional threshold switching, and provide a new technical solution for the development of massive storage and near-memory computing.
Realize the quantum coherent synthesis of ultracold triatomic molecules
Professor You Li of Tsinghua University:
The use of highly controllable ultracold molecules to simulate difficult-to-calculate chemical reactions enables accurate studies of complex systems in all aspects. In 2003, scientists synthesized diatomic molecules for the first time from ultracold atomic gas, and a variety of ultracold diatomic molecules were subsequently prepared in other laboratories and widely used in ultracold chemistry and quantum simulation research. Compared with the two-body system, the three-body classical system is extremely complex and more difficult to solve generally, the quantum energy level structure of the three-atom molecule cannot be accurately predicted in theory, the experimental control is extremely difficult, and the preparation of ultra-cold three-atom molecules has always been a huge challenge in experiments.
The team of Pan Jianwei and Zhao Bo of the University of Science and Technology of China and the team of Bai Chunli of the Institute of Chemistry of the Chinese Academy of Sciences used radio frequency synthesis technology to coherently synthesize ultracold triatomic molecules for the first time in an ultracold mixture of diatomic sodium-potassium ground state molecules and potassium atoms. This research opens up new directions for the study of ultra-cold chemistry and quantum simulation.
Ethylene glycol synthesis is achieved under mild pressure conditions
Professor Gong Jinlong of Tianjin University:
Ethylene glycol is an important chemical intermediate with large demand, and it is of great significance to develop coal-to-ethylene glycol that can replace the petroleum technology route. After more than 30 years of research by a number of domestic research teams, China has made a technological breakthrough in the road of using coal and syngas as raw materials to produce ethylene glycol, and has formed the world's leading production technology and equipment. However, this technical route has problems such as potential safety hazards in industrial production and insufficient stability of product purity and quality, and its core reason is the high concentration of hydrogen and high operating pressure in the hydrogenation reaction.
The teams of Xie Suyuan and Yuan Youzhu of Xiamen University and the teams of Yao Yuangen and Guo Guocong of the Fujian Institute of Structure of Matter, Chinese Academy of Sciences cooperated to use fullerene C60 as an "electron buffer" for modified copper-silica catalysts, and developed fullerene-modified copper catalysts, which realized the synthesis of ethylene glycol by fullerene-buffered copper catalyzed dimethyl oxalate under mild pressure conditions. The research breaks through the problem of low reaction efficiency under the condition of atmospheric pressure and low hydrogen concentration, which is conducive to the green and safe development of syngas to ethylene glycol industry, and will have a far-reaching impact in the fields of coal chemical industry and catalysis.
Discover the new mechanism of micro-nanostructure induced by femtosecond lasers in complex systems
Professor Wang Pu of Beijing University of Technology:
Femtoseconds are 10-15 seconds. Femtosecond laser is a pulsed laser with pulse width of 1-1000 femtoseconds, which has the characteristics of ultra-fast, ultra-strong and ultra-wide spectrum, and has been widely used in scientific research, industrial manufacturing and other fields. When a femtosecond laser is focused inside a material, various highly nonlinear effects occur, and the interaction between light and matter under such extreme conditions is unknown and challenging.
The team of Qiu Jianrong of Zhejiang University, the team of Tan Dezhi of Zhijiang Laboratory, and the team of Gu Min of University of Shanghai for Science and Technology discovered a new mechanism for the formation of micro-nano structures of complex systems induced by femtosecond lasers. Taking the oxide glass system containing chlorobromoiodine ions as an example, the 3D direct lithography of perovskite nanocrystals with adjustable composition and band gap controllable luminescence in the glass was realized, showing different colors of luminescence such as red, orange, yellow, green and blue. The resulting nanocrystals exhibit remarkable stability in ultraviolet irradiation, immersion in organic solutions and high temperatures of 250 degrees Celsius. The research team discovered a new mechanism of femtosecond laser interaction with matter induced by femtosecond laser, which induces liquid nano-phase splitting and ion exchange in the micro-region of glass, and opened up a new technology for three-dimensional semiconductor nanocrystalline structure with a large range of continuous and controllable writing band gap and luminescence in glass, which opened up a new way for a new generation of display and storage technology.
Experiments confirm superconducting "segmented Fermi surfaces"
Professor Zhang Fuchun of the University of Chinese Academy of Sciences:
Superconductivity is an enduring research direction in physics and has important value in basic research and industrial applications. "Segmented Fermi surfaces" are one of the problems in superconductivity research. Fermi surfaces determine the electrical, optical and other physical properties of solid materials, and artificial regulation of Fermi surfaces is one of the most important ways to regulate the physical properties of materials. Superconductors generally do not have Fermi surfaces. In 1965, scientists proposed a theoretical prediction that a special kind of "segmented Fermi surface" could be produced in the superconducting energy gap. The superconductor "segmented Fermi surface" has not been experimentally realized. The reason is that in ordinary superconductors, the superconducting current required to generate a "segmented Fermi surface" is usually close to or even greater than the superconducting critical current, so the superconducting current has already caused the superconductor to overtake before causing the formation of the "segmented Fermi surface".
The teams of Jia Jinfeng and Zheng Hao of Shanghai Jiao Tong University and the team of Fu Liang of the Massachusetts Institute of Technology designed and prepared a topological insulator/superconductor heterojunction system, realized and observed the "segmented Fermi surface" caused by Cooper's pair of momentum with a scanning tunneling spectrometer, and successfully verified the theoretical prediction more than 50 years ago. This research opens up new methods for regulating the state of matter and constructing new topological superconductivity.
Reporter Zhao Yongxin