Global science

New technology

The world's smallest miniature battery

Nowadays, electronic devices such as computers are becoming smaller and smaller, so there is an urgent need to develop smaller micro-batteries compatible with the devices. At present, the integration of micro-battery mainly uses wet chemical method, in which electrodes, adhesives and other materials need to be treated as mud, and the area of the battery integrated by this method is often more than 1 square millimeter. Recently, a study published in Advanced Energy Materials produced miniature batteries less than 1 square millimeter and smaller than a grain of salt using a method called Swiss roll.

The process of this "Swiss roll" method is simply to roll up miniature current collectors and strips of electrodes. The researchers coated the silicon wafers layer by layer with thin polymers, metals and insulating materials. because of the internal stress in the layered system, the film peeled off to release the stress, and the film curled automatically, thus forming a structure similar to the Swiss coil, which can be self-crimped into a cylindrical miniature battery without external force. In addition, this method is compatible with current chip manufacturing technology, so it is possible to fabricate such micro-batteries on silicon wafers with high throughput. The researchers also found that the rechargeable micro-battery can power microchips of similar size for 10 hours, so micro-batteries smaller than salt grains are expected to be used in future micro-and nano-scale electronic devices.

Surroundings

Antarctic pollutants accelerate snow melting

The researchers collected snow samples from a 2000-kilometer stretch of land in the northern Antarctic Peninsula and measured their black carbon concentrations, covering the most active sites for tourist activities and scientific expeditions, as well as more remote areas. The results show that the snow samples around scientific research facilities and tourist areas contain more black carbon than snow samples in remote areas. It is calculated that black carbon reduces snow cover by 23 millimeters each summer in severely affected areas. The researchers estimate that an average of 53,000 tourists arrive in Antarctica each year in the 2016-2020 tourist season, and believe that the amount of black carbon contributed by each tourist may lead to an average of about 83 tons of snow melting in the summer. Researchers believe that people should reduce the accumulation of black carbon in Antarctica in a variety of ways, such as the use of cleaner energy, the use of hybrid or electric ships and restrictions on the number of tourists, in order to reduce the burden of human activities on the environment in Antarctica.

Neuroscience

"singing neurons" in the human brain

There are parts of the brain that respond to a variety of music, but it is not clear how these regions code the response to music. In a new study, scientists combined different brain activity detection techniques and found an area in the auditory cortex that selectively responds to singing sounds. The study has been published in current Biology.

The scientists first used electrocorticography (electrocorticography) to record the electrical activity of 15 subjects. They asked 15 subjects to listen to 165 different sounds, including speech, music, finger tapping, dog barking, etc., and through algorithm analysis, they found that some clusters of neurons could respond to singing, but the response to speech or pure music was weak. The scientists then combined data collected by functional magnetic resonance imaging (fMRI), which can detect a wider range of brain regions, to locate neuron clusters more accurately. They found that these "singing neurons" were located at the top of the temporal lobe of the brain, close to areas of the brain that selectively respond to language and music, suggesting that these neurons may be able to respond to characteristics such as the mixed effect of words and pitch. The researchers hope to further study the specific aspects of singing that trigger the response of these neurons and the developmental mechanisms of these brain regions.

Scientific event

National Science and Technology Expenditure 970 billion in 2021

On February 22, at a press conference held by the Information Office of the State Council on financial reform and development, Minister of Finance Liu Kun introduced the relevant work of the Ministry of Finance in implementing the innovation-driven development strategy in 2021 and supporting scientific and technological self-reliance. In 2021, national expenditure on science and technology totaled 970 billion yuan, an increase of 7.2 percent over the same period last year. While expenditure at the central level continues to grow negatively in 2021, by adjusting the expenditure structure, the central level's expenditure on science and technology still reached 320.554 billion yuan, with emphasis on basic research, and the central level's expenditure on basic research increased by 15.3%. In 2021, the Ministry of Finance actively improved the central financial management of scientific research funds, expanded the autonomy of project funds management in the field of scientific research, and increased the proportion of indirect expenses based on the actual needs of scientific research work. At present, more than 50% of the funds for scientific research projects are spent on "people", which reduces the routine burden of researchers to a large extent, and creates a good atmosphere for researchers to study hard and produce more high-quality scientific research results. (science and Technology Daily)

Physics

Recently, a study published in Nature Physics used the world's largest X-ray laser and microimaging spectrometer to capture clear images of complex molecules of iodopyridine at the atomic scale. This is the sharpest image ever taken of a complex molecule. These images are important for recording future videos of molecular changes, while high-resolution videos can provide details of chemical or physical changes.

The researchers used a method called Coulomb explosion imaging. High-intensity, ultra-short-wavelength X-ray lasers can "knock out" most of the electrons in the molecule, freeing them from the binding of the molecule. At this point, the electrostatic repulsion between positively charged atoms causes the molecule to explode in femtosecond. Subsequently, the ion fragments separated after the explosion are "guided" by the electric field into the detector to be imaged, and then the images of the fragments are pieced together into molecular images according to the exact location and time of the fragments. Previously, this method was mainly used to image small molecules with no more than five atoms, but now the study breaks through this limit.

Material science

New type of strong and tough elastic material

Ionic gel is a kind of solid mixture material composed of polymer and liquid salt electrolyte (ionic liquid), which has excellent ionic conductivity, thermal stability, electrochemical stability and non-volatility. However, most of the existing ionic gel materials have low strength and toughness, and it is difficult to synthesize. Recently, a new study published in the journal Natural Materials has invented a new type of ionic gel with both toughness and elasticity.

The researchers used ultraviolet light to copolymerize acrylic acid and acrylamide in a 70% ionic liquid solution. The results showed that the average level of the gel was better than that of the above two monomer materials, and it was better than cartilage in terms of toughness. In addition, the ionic gel has the properties of self-healing and shape memory. For example, when it is exposed to 60 ℃, it can return to its original shape in tens of seconds.