Chapter 439: Rubbing room-temperature superconducting materials by hand?
After answering a few questions, the bell rang for the end of get out of class.
When he heard the bell ringing, Xu Chuan quickly picked up the teaching materials from the podium and quickly slipped out of the classroom.
He is quite experienced in this aspect. After all, he was blocked once in class before without paying attention, and it took him a long time to get out.
So the best way is to announce the end of get out of class and leave before these 'enthusiastic' students gather around.
Following the corridor, Xu Chuan quickly slipped out of the teaching building.
Just as he was about to return to his office, he bumped into Tan Shaoyuan, the new president of NTU.
Principal Tan smiled and said hello, walked over and asked: "Academician Xu has finished his class? How do we NTU students feel?"
Xu Chuan smiled and said: "It's good. These students are very serious and enthusiastic."
Tan Shaoyuan smiled and said: "It's all thanks to you, Academician Xu. With you here, the scores and quality of admissions at Nanjing University in the past two years have become better and better year by year."
I have to say that NTU’s enrollment has improved a lot in the past two years, both in terms of scores and quality.
Among them, Xu Chuan’s influence was too great.
Nobel Prize winner, Fields Medal winner, chief architect of the national controllable nuclear fusion project..., a series of reputations and achievements have made NTU follow him out of the circle again and again.
Including the Department of Mathematics, which was originally mediocre and even a bit out of place among universities, has now taken off. There are even many mathematics competition students who have chosen to apply for NTU.
In the past, these students almost always went to Shuimu or Peking University, or even worse, to Fudan or Xiangdao. The Mathematics Department of Nanjing University was basically not among their considerations.
Xu Chuan smiled and said, "It's an honor for me that my alma mater has grown stronger."
After a slight pause, he continued: "By the way, talking about the principal, regarding teaching, I have something to trouble the school about."
Upon hearing this, Tan Shaoyuan quickly replied: "Academician Xu, please speak."
Xu Chuan: "I'm going to take a few students here and want to see if there are any suitable ones. Can the school help to screen them first?"
Hearing this, the principal Tan in front of him nodded without hesitation and said, "That's no problem. I'll find someone to arrange for statistics on the students as soon as I get back."
"But regarding students, do you have any requirements?"
Xu Chuan thought for a while and said: "I will take care of students here, even undergraduates. I don't have the energy. I usually just give them classes. I mainly accept graduate students and doctoral students."
"For graduate students, the postgraduate entrance examination score should be at least 380 points and the professional score should be no less than 90 points. If you have excellent SCI papers and experience in various scientific research projects, the test scores can be lowered."
"As for doctoral students, evaluation is mainly based on papers and scientific research project experience, and performance is secondary."
For him, taking care of students is no longer limited to a certain school. He can basically recruit students from all over the country or even the world as long as he opens his mouth.
However, considering that this should be the first group of students he would truly bring after returning to China, Xu Chuan was still prepared to give this opportunity to students from his alma mater first.
Tan Shaoyuan nodded and said: "No problem, I will handle it as soon as I get back. Do you have any other needs?"
Xu Chuan smiled and said: "No more for now, then I'll have to talk to the principal about this matter."
"Hey, what's the trouble? No trouble, no trouble. This is my job." Tan Shaoyuan waved his hand and said, "These students selected by you are a blessing to them and Nanjing University."
Xu Chuan smiled, bid farewell to the newly appointed Principal Tan and returned to his office.
The room was empty, and Cai Peng didn't know where he had gone. He didn't pay much attention. He turned on the computer and began to improve the aerospace engine idea that he had not finished last night.
Aerospace and aviation are two different concepts.
Although their meanings may sound similar, they are very different.
Aerospace refers to the general term for various activities involving entering, exploring, developing and utilizing space and celestial bodies beyond the earth. Engines need to work in an oxygen-free environment.
Aviation only refers to the flight (navigation) activities of aircraft in the earth's atmosphere (air space), which generally requires oxygen in the atmosphere as fuel.
The two are not the same thing in the same sense.
Currently, aerospace engines are divided into four major types: solid fuel rocket engines, liquid fuel rocket engines, electromagnetic engines, and nuclear energy engines.
Liquid fuel rocket engines, which are commonly used in various countries, generally use liquid fuel as aerospace engine fuel.
Although the thrust of solid fuel rockets is much higher than that of liquid fuels at the same weight, and the structure is simpler. However, the burning time of solid fuels is quite short, and ordinary launch vehicles can only last two or three minutes.
It is almost impossible to send satellites or spacecraft into space in such a short time.
Coupled with problems such as the inability to adjust thrust and unstable combustion, solid fuel is still relatively rarely used in today's rockets.
Of course, in Xu Chuan's view, both solid fuel rockets and liquid fuel rockets have an unavoidable shortcoming.
That means the specific charge value is too small.
Compared with electromagnetic aerospace engines, the maximum specific impulse value of fossil fuel engines does not exceed 500 seconds.
The most common electromagnetic aerospace engines can easily achieve a specific impulse of more than one thousand seconds, and those electromagnetic engines with excellent performance can even achieve a specific impulse of more than five thousand seconds.
The so-called specific impulse, if described in professional terms, refers to a measure of the efficiency of a reactive mass engine (a rocket using propellant or a jet engine using fuel) to produce thrust.
Of course, if you want to understand it simply, it can be understood as "the time that a rocket engine can last for one kilogram of thrust generated by one kilogram of propellant."
This chapter is not over yet, please click on the next page to continue reading! Just like the American space shuttle, its main engine propellant is generally liquid oxygen/liquid hydrogen, and the vacuum specific impulse is 452.3 seconds.
But behind the high specific impulse of electromagnetic space engines, the weakness is that the thrust is much lower than that of fossil fuels.
The thrust of today's electromagnetic aerospace engines is generally around micronewtons or millinewtons.
This level of thrust is indeed feasible in space in a vacuum state. After all, there is no resistance. As the electromagnetic space engine continues to work, the speed can also increase.
But if you put it in the atmosphere...
It is no exaggeration to say that it does not even have the ability to send an egg into space.
No one doubts the potential of electromagnetic space engines in the future after the controllable nuclear fusion technology is realized.
But now, even he, as the 'father of controllable nuclear fusion', is having a headache over this.
Even if he can find a way to try his best to shrink the controllable nuclear fusion reactor, or use a miniaturized fission reactor, and then use the magnetic fluid generator to shoehorn it into the spacecraft, the thrust of the electromagnetic space engine is too weak and it is still a
Huge trouble.
"Perhaps, I should refer to the opinions of experts in the aerospace field in this regard. After all, I am not a professional in the field."
After recording some of the ideas in his mind, Xu Chuan planned to find experts from the aerospace industry in the future to see if he could realize a high-power electromagnetic aerospace engine system.
As for the method of fossil fuel propulsion, it has been thrown out of the scope of his consideration at present.
After all, chemical fuel rockets have now reached their end, and it is almost impossible to significantly increase the specific impulse.
But if high-thrust electromagnetic aerospace engine technology and high-energy-density power supply equipment can really be realized, electric thrust technology has the potential to replace fossil fuel rockets with its advantage in specific impulse.
What's more important is battery life.
If nuclear fusion is used to power a spacecraft, in addition to being able to travel between the surface and space, the spacecraft will also have the ability to travel to distant places such as the moon and Mars.
Even with sufficient energy supply, the speed of the spacecraft can be increased several times, greatly shortening the time required to travel between the moon and Mars.
.......
After recording some of the thoughts in his mind, Xu Chuan opened the browser and searched and browsed for some things that had happened in the scientific community in the past two years.
After presiding over the Qixia Mountain Controlled Nuclear Fusion Project for more than two years, he almost left the world of mathematical physics.
Although he still had continuous contact with some former acquaintances, he was really not sure if anything else had happened in the mathematics and physics circles in the past two years.
While browsing through some events in the mathematical physics community over the past two years, a timely notification from Arxiv caught his eye.
【The first room temperature and normal pressure superconductor!】
Seeing the pop-up box in the lower right corner, Xu Chuan was obviously stunned for a moment.
Room temperature superconducting materials?
what's the situation?
Quickly sliding the mouse with his right hand, he clicked on arxiv's push and entered this link.
"Abstract: The first room temperature and normal pressure superconductor, Subey Lee, Kim Ji-hoon, Kwon Yong-yun."
"We have successfully synthesized for the first time in the world a room temperature superconductor (Tc ≥ 400k, 127°c) working at ambient pressure with a modified lead apatite (KL-66) structure. The superconductivity of KL-66 is achieved through critical
Temperature (Tc), zero resistivity, critical current (Ic), critical magnetic field (Hc), and the Meissner effect. The superconductivity of KL-66 results from tiny structural distortions caused by slight volume shrinkage (0.48%)
, rather than external factors such as temperature and pressure.”
"The shrinkage is caused by the substitution of copper 2 lead 2 (2) ions in the lead phosphate insulating network, and generates stress. It is simultaneously transferred to the Pb(1) of the cylinder, causing deformation of the cylinder interface, which creates
Superconducting quantum well (sqw). The heat capacity results show that the new model is suitable to explain the superconductivity of KL-66."
"The unique structure of KL-66 allows for the maintenance of a tiny twisted structure in the interface, which is the most important factor for KL-66 to maintain and exhibit superconductivity at room temperature and ambient pressure..."
The short abstract provided by arxiv was quickly reviewed by Xu Chuan, and at the same time, the corresponding paper had been downloaded.
Impatient, he quickly clicked on the downloaded paper.
Room temperature superconductivity?
I had never heard of any outstanding research in this area in South Korea in my previous life. Why did this suddenly appear?
With deep doubts in his heart, Xu Chuan quickly scanned the entire paper.
However, after reading the paper, all he could see in his eyes was the word 'outrageous' in capital letters.
Nothing else.
Just because this method of synthesizing the KL-66 room-temperature superconducting material simply refreshed his knowledge.
In the first step, pyrite is synthesized through a chemical reaction. Lead oxide and lead sulfate powders are evenly mixed in a ceramic crucible at a ratio of 50% each. The mixed powder is heated in a furnace at 725 degrees Celsius in the presence of air.
24 hours. During the heating process, the mixture undergoes a chemical reaction to produce pyrite.
The second step is to synthesize cuprous phosphide crystals. Mix copper and phosphorus powder in a crucible according to the proportion. Seal the mixed powder in a thyristor of 20 cm per gram, with a vacuum degree of 10 -3 tor. Mix the powder containing
Sealed tubes of the powder are heated in a furnace at 550 degrees Celsius for 48 hours, during which time the mixture reacts and forms cuprous phosphide crystals.
The third step is to grind the pyrite and cuprous phosphide crystals into powder, mix them in a crucible, and then seal them into the thyristor with a vacuum degree of 10 -3 power. Place the sealed tube containing the mixed powder in
Heating in a furnace at 925 degrees Celsius for 5-20 hours. During this process, the sulfur element in the lead sulfate evaporates during the reaction, and the mixture reacts and transforms into the final material, KL-66.
This chapter is not finished yet, please click on the next page to continue reading the exciting content! Not to mention the three steps, the synthesis process is extremely simple, and the raw materials can be found everywhere.
According to the methods and steps given in the paper, the synthesis method of this new material is undoubtedly similar to "hand rubbing".
That's right, you can actually rub it with your hands.
If this method can really synthesize room temperature superconducting materials, then even he can't help but wonder whether the technological tree that mankind has established in the field of materials is completely crooked.
The synthesis method and materials of this superconducting material are a bit too ‘cheap’.
........
Of course, Xu Chuan did not immediately deny that this room temperature superconducting material called KL-66 was fake.
No matter how outrageous or crude its synthesis process is, it requires rigorous and multiple experiments to confirm or disprove it.
And to be honest, in the field of materials, it is not impossible for something similar to happen.
After all, with just a piece of tape, you can stick the most versatile material in the world, graphene, and win the Nobel Prize. This is something that has really happened in history.
If you tell people about this kind of thing, they will just think that it is a novel written by a dog author who does not understand science.
After all, it's a bit too outrageous.
The same goes for South Korea's KL-66 material. Even though its synthesis process seems a bit outrageous and crude, in the field of materials, it is not impossible.
Sometimes, maybe you can put a "koi" who is extremely lucky and knows nothing about materials into the project team, and maybe it can bring you good luck and produce something that can make you happy in the blink of an eye.
New materials to provide you with food and clothing for the rest of your life.
Materials, this is probably a field that, apart from experience, is entirely Ou Huang's domain.
