What of this scientific knowledge do you know?

What of this scientific knowledge do you know?
What of this scientific knowledge do you know?

Chen Ming shared his "journey in search of holes" and "search for stones in all mountains."

What of this scientific knowledge do you know?

Luo Shixiao shared his story of unraveling mystery of star anise "swat".

What of this scientific knowledge do you know?

Fang Tianhui shared story of how he made a breakthrough in floating wind power in my country.

What of this scientific knowledge do you know?

Fu Yicheng shared her story on how to build a barrier-free city.

Search for rocks in mountains and plains to "fix name" of crater, and squat all night to find "matchmaker" for star anise... A few days ago Guangzhou Science and Technology Center 2022 Week and 17th release of Gezhi On Dao Bay Area magazine was held in Guangzhou. The topic of this forum is "Upgrade! Knowledge,” and we invited a number of guests from Guangdong-Hong Kong-Macau Great Bay area to share their scientific research stories on how to overcome barriers of knowledge and make impossible possible. Text, photos / All media reporter Guangzhou Daily Fang Qing

Why are only two craters in China recognized by international community?

Currently, about 200 impact craters have been discovered on Earth. China has a vast territory, but only two craters are internationally recognized. Why? Chen Ming, a researcher at Guangzhou Institute of Geochemistry of Chinese Academy of Sciences, explained "diagnostic criteria" of crater and shared his "travel in search of crater" by "looking for rocks all over mountains."

"Actually, most craters don't look like craters." Chen Ming said that movement of tectonic plates, mountain building, movement of glaciers, weathering and erosion, and deposition and burial can lead to destruction of craters on earth's surface. , erosion. In addition, rock formations in China are relatively "young" and terrain is complex. The orogenic belt accounts for three-fifths of country's territory. With a strong geological impact, craters are easily damaged or buried, making it difficult to find craters...

The general shape of craters is round, but not all craters on Earth are craters, and not all craters contain meteorites. This is due to fact that impact energy of planet is very high, and, as a rule, at moment of impact, meteorite breaks, melts and gasifies, even if a small amount of fragments remain, they are destroyed as a result of physical and chemical weathering at moment of impact. long geological years. It exists or is difficult to find, so meteorites cannot be found in most craters.

How to find crater? "We have only one way - to look for rocks in all mountains and fields and find those stones that have been heavily affected." rocks and minerals. When an asteroid strikes surface at ultra-high speed, rocks undergo physical and chemical changes at high temperature and ultra-high pressure, forming ultra-high pressure minerals, impact glass, and other substances. This shock wave effect is unique to craters. .

Chen Ming spent 15 years looking for craters. He said: “When we talk about universe, we often say that it is meant for astronauts. In fact, craters on Earth are similar to craters on Mars and Moon. The geological phenomenon of craters is same. If we can find craters around us, we can "to stand on themle and look at planet. Many craters abroad have turned into museums, and these two craters in China are also very ideal. . Address of Museum of Natural History."

Why is it difficult to grow star anise on a large scale outside of original area?

Why, for hundreds of years, star anise could not be grown on a large scale outside of its origin in Guangxi? To unravel this mystery, Luo Shixiao, a researcher at South China Botanical Garden of Chinese Academy of Sciences, squatted all night watching star anise bloom and found a matchmaker who pollinated it, not a familiar bee, but a mosquito.

The story of Luo Shixiao, who found star anise as a matchmaker, is both complex and interesting. The flowering period of star anise safflower falls annually at end of March-mid-April. During this short period, neither he nor his younger brother have ever seen real insects visiting flowers. At that time, Luo Shixiao was on a business trip to Hainan, and they collected blooming flowers into sealed bags and brought them back to laboratory. Due to rush of trip, this flower bag was placed on table. Upon returning, Luo Shixiao found that in addition to flowers, sealed bag contained many maggot-like larvae, so he threw it into trash can.

Shortly after being thrown away, Luo Shixiao changed his mind: "There shouldn't be so many larvae born in office. Maybe some worms laid eggs in flowers while picking flowers." When flowers were plucked. Autopsy and observation under a dissecting microscope showed that structure and shape of larvae are basically same. Taking a 5kg box of dissecting mirror with him, Luo Shixiao ran to experimental site on mountain, made observations under dissecting microscope immediately after picking flowers, and found that flowers did indeed contain insect eggs.

Subsequently, through many years of field observation, Luo Shixiao discovered that a kind of turpentine midge, following unique flower scent, visit star anise flowers and lay eggs in flowers, and turpentine midge also use pollen wetted on its body to pollination of plants. After pollination, columns close, forming a natural greenhouse for reproduction of larvae, which speeds up hatching of eggs. After eggs hatch from flowers that do not produce nectar, a lot of secretions are released, providing food for larvae and helping turpentine gall midge to complete process of raising offspring. A mutualistic symbiotic relationship has developed between star anise and turpentine gall midge: “you pollinate me, and I raise children for you.”

Referring to importance of study, Luo Shixiao said, "The study of pollinators can promote development of a new type of fruit from wild to domesticated and improve people's understanding of use of wild resources. At same time, we must protect pollinators so that more people care about biodiversity and protected him."


How to realize floating wind power by "playing tai chi" in sea?

Fang Tianhui, Deputy Director of Department of Shipbuilding and Ocean Engineering, South China University of Technology, and his team participated in research and development of my country's first offshore floating wind power system, "Three Gorges Pilot", which achieved my country's floating wind zero breakthrough . This floating offshore wind farm is located in Yangjiang, Guangdong province. Each unit can generate 5500 degrees per hour at full load and can provide green and clean energy to 30,000 households every year. It is expected to reduce carbon emissions by about 20,000 tons. per year, which will greatly alleviate shortage of electricity for residents of Great Bay area.

It's not easy chasing waves in deep sea. If stationary offshore wind power directly injected into sea is built with a "golden bell", then practice of floating wind power connected to seabed with a mooring line is "playing Tai Chi". Fang Tianhui explained that floating structure consists of a floating body that supports weight of windmill and floating body itself, and then uses a fastening system, that is, several large ropes, to connect it to sea. “The whole system is very soft. When waves come, my floating body shakes, when wind blows, spring moves under tension of several large ropes, and with its movement resists external wind and wave force. The effect is equivalent to practice of tai chi kung fu, which emphasizes unloading."

So, how to realize floating wind power by "playing tai chi" in sea? The key is mooring system. Find a large medium-strength rope that can hold back movement of floating body like a spring. If it is too soft, platform will move further, which can damage cable, if it is too hard, there will be no spring unloading effect. “Even though we think of it as a spring, it's not a real spring, it's a very complex system. The length, shape, location of rope, including its material, weight, and even diameter all have a big impact on softness. and stiffness of whole rope. It matters a lot."

To this end, Fang Tianhui and his team independently developed a mooring design software that can automatically design a mooring line suitable for construction by only determining needs and goals, "finding a good design for a large rope." This technology has filled a gap in this field and broken foreign monopoly to a certain extent. It is understood that independent research and development rate of Three Leading Gorges Project exceeds 95%, which fills a gap in development of equipment for floating offshore wind power systems in my country.

“Floating offshore wind power is only way to developwind power in my country in deep sea. At present, construction of floating offshore wind power in China is still in exploration and demonstration stage. I hope more people will actively participate in offshore wind power and make impossible possible,” said Fan Tianhui.

How to build a barrier-free city?

In total, there are 85 million disabled people in our country, while at same time there are more than 253 million elderly people over 60 years old, and our country has entered an aging society. Whether it is meeting vital needs of disabled or preparing for an aging society, a barrier-free city must be built for all people of all ages.

Urban planner Yi Cheng and his team from Shenzhen Branch of China Academy of Urban Planning and Design are responsible for special planning for barrier-free cities in Shenzhen. They studied 194 test sites and found that barrier-free traffic environment in many areas has serious problems, such as intermittent blind roads and substandard design. To this end, they drew a figure and a table of "barrier-free facilities" as a guideline for strengthening comprehensive construction of barrier-free cities.

In addition to removing barriers to urban mobility, accessibility within communities is equally important. Fu Yicheng mentioned that people with disabilities spend 85% of their time in community, and implementing barrier-free access in community is first step towards solving problem of travel for disabled. Fu Yicheng and his team visited community, listened carefully to views of residents, and promoted public participation in development of barrier-free reconstruction. From parking lot repairs, to rehabilitation, care and repair of community shelters, to special education schools for children with autism, she and her team are committed to advancing Barrier Services comprehensively evolving in direction of "medical care, education, education and entertainment."

Fu Yicheng also mentioned, "Barrier-free access is not only a problem for certain groups of people, but also a problem for all people, all ages, and entire society."