Are Chinese rockets really starting to burn "coal"? | Expo Daily

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Long March rocket coal power , green, environmentally friendly and more economical

On November 30, the Long March 12 carrier rocket, which uses the State Energy Group's coal-based aerospace kerosene as its main power fuel, successfully completed its maiden flight at the Wenchang Space Launch Center in Hainan.

As my country's new generation of space launch vehicle, the Long March-12 carrier rocket has verified the compatibility of coal-based space kerosene with my country's new pump-swinging liquid oxygen-kerosene engine, laying a solid foundation for my country's subsequent major space projects.

The coal-based aerospace kerosene used in this launch is made mainly from the direct liquefied coal oil of the State Energy Group. It is based on coal resources and has effectively freed my country's aerospace field from long-term over-reliance on traditional petroleum resources. The specific impulse performance, cooling characteristics, flow resistance performance, combustion characteristics, etc. of coal-based aerospace kerosene are consistent with those of petroleum-based aerospace kerosene, and its performance is stable.

Different from traditional petroleum-based aerospace kerosene, coal-based aerospace kerosene solves the historical problem of too single source of aerospace kerosene raw materials. It conforms to my country's energy status quo of "rich in coal and poor in oil", effectively guarantees the strategic security of national aerospace energy, and has good specific impulse performance, product consistency and stability.

Compared with traditional rocket propellants, kerosene, as the main power of the new generation of high-thrust rocket engines, has the characteristics of high thrust, green environmental protection, convenient storage and transportation, and high economy. This is also the first time that the Long March series of launch vehicles have used coal-based aerospace kerosene to fly into space, and the dream of the Long March to burn "coal" has become a reality.

Image source: Xinhua News Agency

The road to losing weight is difficult , and the memory of fat is in your heart!

Have you ever tried to lose weight with a friend? You found that the results were very good at first, so you thought of indulging yourself and had a hot pot meal. As a result, your weight increased by 3 catties the next day, and you didn’t lose weight even after exercising for several days. It was really frustrating.

Scientists have given this phenomenon of putting weight back on after a little indulgence a name - the yo-yo effect. In a recent Nature magazine, researchers reported their research on the yo-yo effect. It turns out that this is related to the epigenetic "memory" of fat cells.

The study showed that obesity causes characteristic epigenetic changes in the nuclei of fat cells. What is special about these changes is that they persist even after dieting.

In other words, fat cells remember that they were once overweight and can return to that state more easily. Studies have shown that fat cells that were once "fat" will absorb fat more efficiently when faced with a high-fat diet in order to return to an overweight state.

Researchers have not yet studied how long fat cells can remember being fat. But fat cells are long-lived cells. On average, they can live for ten years before our bodies replace them with new cells. It is because of this memory effect that it is so important to avoid being overweight. Because once you are overweight, your cells remember what it was like to be overweight and try to restore this overweight state.

Image source: pixabay

Dinosaurs ruled the daytime, and "bulk mice" had sharper eyes

In fact, the common ancestor of all vertebrates could see four colors, three colors plus ultraviolet light. We humans can see three colors, which is the best in the mammal world. But in the entire vertebrate world, our color vision is actually not as good as that of fish, let alone birds, the descendants of dinosaurs.

Unable to fight the dinosaurs that were active during the day, the ancestors of mammals could only choose the night and became a bunch of "loose rats". In this way, our ancestors spent nearly 200 million years in darkness, hiding in caves during the day to avoid dinosaurs, and only coming out at night to rely on the protection of darkness.

In the dark, you can't see any colors. It doesn't matter whether you have color vision or not. It's better to degenerate color vision to enhance night vision so that you can see things in low light conditions. Therefore, many mammals now have a pair of "titanium dog eyes" that shine brightly at night, and the four-color vision is reduced to only two.

In addition, nocturnal movement strengthens rod cells: the color vision mentioned above is determined by cone cells. For example, birds can see four colors, so they have four types of cone cells. But when the light is dim at night, cone cells cannot work and rod cells must be used instead. Compared with cone cells, rod cells are more sensitive to light, but they can hardly distinguish colors, and can only distinguish the brightness and darkness of grayscale.

Even if only one rod is stimulated by a photon, the brain thinks that the entire area where these rods are located is stimulated. But since the brain does not know which part of the area (which rod) is transmitting the information, the visual acuity is quite low. This is why people see things in low light as blurry and gray...

Badger's "titanium alloy dog ​​eyes" Image source: Wikipedia

The fluffy down has strong warmth retention and is really good at blocking out cold wind!

In terms of warmth retention, there is no other thermal insulation material in the world that can surpass the warmth retention performance of down. This is due to the special structure of down - the spherical fiber structure. Each down fiber is composed of many scales stacked together, and each scale is hollow. In these tiny pores, a large amount of still air can be fixed.

When you put on a down jacket, the down can absorb the body's heat and form an air insulation layer. The more air the insulation layer fixes, the better the warmth retention performance. In addition, the outer fabric of the down jacket can isolate the outer cold air, which can more effectively reduce the convection exchange between the air layer of the down and the outside air.

The warmth retention of down jackets is mainly reflected in the thickness of air that can be stored after the down is fluffy and the ability of the surface layer to isolate cold air. Therefore, a good quality down jacket should not be washed too many times without affecting the clean wearing conditions. Frequent washing will damage the fiber protein structure of the down, making the down hard and brittle, affecting the warmth retention, and will also cause certain damage to the fabric and increase the possibility of hair drilling.

If you want to wash your down jacket, you can choose dry cleaning or water washing according to the down jacket washing label. If you wash it with water, try not to use a washing machine. It is best to wash it by hand and rub it clean. After washing, do not wring it directly. You should squeeze out the water gently and then lay it flat or hang it up to dry. At the same time, after washing, pat the clothes to restore their fluffyness. The force should also be as gentle as possible to reduce damage to the down and extend its service life.

Scanning electron microscope photo of duck down. Image source: Huang Chen. Comparative analysis of the performance of three types of down fibers[J]. Wool Textile Technology, 2021, 49(07), 85-89.

Besides Man Guangzhi , is this the one the world most wants to capture alive?

Our universe is filled with a large number of neutrinos, most of which are remnants of the Big Bang, about 300 per cubic centimeter. Scientists generally believe that neutrinos, which are widely present in the material world, contain important information about the antimatter world.

However, neutrinos are too hard to catch. They are not blocked by seawater and strata, and cannot be interfered with, intercepted or cracked, so the detection of neutrinos is very difficult. Among all elementary particles, neutrinos are the least understood, so neutrinos are also called "ghost particles."

According to the Chinese Academy of Sciences, the world's largest single plexiglass sphere has been fully built inside the central detector of the Guangdong Jiangmen Neutrino Experiment (JUNO), located 700 meters underground, and has entered the final stage of construction.

Netizens joked, "Ghosts finally have a high-sounding name - neutrinos. If neutrinos are found 700 meters underground, it means that a ghost has been caught in the underworld."

The content is compiled from China Science Expo Weibo, Xinhua News Agency, Science Academy, Museum, Science Popularization China

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