Seeing that the niobium metal piece in the machine was floating exactly as he imagined, Chen Muwu did not care about launching rockets and satellites with Huxley and Wells, but left them behind and ran straight to the machine. .
Everything was going step by step according to Chen Muwu's plan, but even so, he kept a shocked expression on his face and kept muttering to himself: "What the hell, what the hell, how is this possible? "
"Dr. Chen, what happened?"
Wells and Huxley also rushed over after him, and the latter quickly asked him about the current situation, fearing that he would bring people into the laboratory today, which would affect and damage Chen Muwu's experimental results.
The Davy-Faraday Laboratory is one of the hottest laboratories in the UK today, and research on superconductivity in low-temperature physics is the laboratory's flagship project.
If something goes wrong in Chen Muwu's superconducting experiment due to the arrival of these two people, then they will definitely be blamed, and they might even become the biggest sinners in Britain.
"Professor Huxley, the experimental phenomena are somewhat unexpected. They are completely different from those of ideal conductors," Chen Muwu pointed at the reading on the helium thermometer and said, "Look, the ambient temperature inside the instrument has now reached 8 Kelvin. This temperature is lower than the critical temperature of niobium, indicating that the sample has entered the superconducting state at this time.
"According to previous assumptions, after the sample enters the superconducting state, it can be regarded as an ideal conductor, but an ideal conductor will not float in a magnetic field."
"Dr. Chen, what does the current phenomenon mean?" Wells also asked with some worry.
"It's hard to say," Chen Muwu shook his head deliberately, "I may have to repeat this experiment a few more times to see if there are other factors that interfere with the experiment. If the result is still the same after repetition, then it means that niobium, Or other metals cannot be regarded as ideal conductors after entering the superconducting state, and a new explanation needs to be given to them."
Wells wanted to continue asking. Didn't Dr. Chen just say that after the material becomes superconducting, it can be suspended in a magnetic field?
Now that the result has been obtained, the piece of metal called niobium is floating quietly in the instrument, but why is he making such a fuss?
It was a pity that Chen Muwu would not give him a chance to ask questions again. Seeing that the phenomenon he wanted to obtain finally appeared, the work of the two guests as witnesses in the laboratory was completed. It was time to serve tea to see off the guests.
"Mr. Wells, Professor Huxley, I'm sorry. I originally wanted to demonstrate superconductivity to you two today, but unexpectedly, the experiment unexpectedly changed, and a new effect seemed to be produced.
"Next, I will be conducting research on this new experimental phenomenon, so I probably won't have time to continue introducing things about superconductivity to you two. I'm really sorry!"
"It's okay, it's okay, Dr. Chen, your experiment is important. Then let's leave first without disturbing you to continue your scientific research."
Seeing that there was no anxious look on Chen Muwu's expression and his tone of voice was quite calm, Huxley finally felt relieved.
But he still felt that it was not suitable to stay here for a long time. As soon as Chen Muwu saw off the guests, he hurriedly took Wells and left.
But Wells still wanted to continue chatting more with this interesting young man. Although the thing he said about launching cannonballs into the sky is a cliché, it is still quite interesting to say that in the future, trains will be able to fly close to the ground without using rails. .
Before leaving, Wells did not forget to invite Chen Muwu to meet him next time: "Dr. Chen, after you complete this experiment, you are welcome to come to my home as a guest."
"Mr. Wells, if I have the opportunity, I will definitely visit you at home."
After the two people left, Chen Muwu did not continue his research, but turned off the machine directly. After cleaning the remaining frozen fruits, he leisurely clocked in and went home from get off work.
Just discovering this experimental phenomenon is not enough. Tomorrow, he has to guide his two students and ask them to give a reasonable explanation for this experimental phenomenon.
Although Shi Ruwei is the first author of the paper that developed the superconducting effect of metallic niobium, niobium is not a ceramic after all, and its superconducting critical temperature is not high enough. This small discovery alone will not win the Nobel Prize. Awarded.
But coupled with the complete diamagnetism of superconductors, it should be very competitive.
"Tell me, what do you two think about this novel phenomenon?"
The next day, after re-demonstrating to Shi Ruwei and Oppenheimer the new phenomenon of niobium spontaneously floating out of the magnetic field after entering a superconducting state, Chen Muwu raised his own question.
Oppenheimer shook his head in confusion.
Although he is not good at doing experiments and is better at thinking about theoretical issues, magnetism is still a very partial branch of physics for him.
Teacher Chen is a master in relativity and quantum mechanics. After attending Cambridge, Oppenheimer has been working hard in these two areas, but he never expected that he would also have such high attainments in the study of magnetism.
People are more likely to die than others. To Oppenheimer, Chen Muwu was a peak that could never be reached.
This reminded him of a newly learned Chinese idiom, which is called "High Mountain Yang Zhi".
But Shi Ruwei was different. After he entered the University of Cambridge last year, he not only followed Chen Muwu's request to study theoretical knowledge in university classrooms and libraries, but was also arranged to study at Cavendish by Chen Muwu, seemingly intentionally or unintentionally. In the laboratory, I followed Kapitsa, the assistant head of the Magnetism Department, and the one who met Stoner when he and de Broglie were doing experiments together, and they did research together.
After this year, although Shi Ruwei cannot be said to be proficient, he still accumulated a lot of knowledge about magnetism.
Oppenheimer had already expressed his position, but Chen Muwu never spoke. Instead, he stared at the two people with a smile. It seemed that he was waiting for Shi Ruwei to express his thoughts.
"Brother Hanchen, since this piece of niobium can float, it means that there must be a lifting force, and the magnitude of this lifting force must at least be greater than the gravity of the metal piece."
Chen Muwu nodded and motioned for him to continue.
"This kind of lift is definitely not the buoyancy force brought by the air, and it is in a magnetic field. It is easy to think that this should be an electromagnetic repulsion generated based on the magnetic field.
"Think again of the behavior of an ideal conductor in a magnetic field, and compare it to the experimental phenomenon of first making the metal enter a superconducting state, and then adding a magnetic field. I think it may be that the niobium metal enters the superconducting state due to cooling. After that, all the magnetic field lines in its body are discharged. In other words, it generates a new magnetic field in the opposite direction to the environmental magnetic field."
Oppenheimer still looked confused, while Chen Muwu nodded and smiled: "Heroes see the same thing, and I think the same way. It's just that thinking with your brain is not enough. Physics is an experimental science. Let's continue The next thing to do is to design experiments for verification.
"But before that, I think we should try a different element, say, lead."
Niobium is a paramagnetic metal, while lead is a diamagnetic metal, and the two metals behave somewhat differently in magnetic fields.
If the lead metal sheet is also like niobium, a magnetic field is first applied and then cooled, and it is also suspended in the magnetic field after entering the superconducting state, then it can be shown that this behavior is not unique to paramagnetic materials, but applies to all materials. It is applicable to both, whether paramagnetic or diamagnetic, they will discharge the magnetic field lines in their bodies when superconducting and become a diamagnetic substance.
Meissner also considered paramagnetism and diamagnetism when doing experiments at that time.
As a diamagnetic metal, his choice was of course lead.
It's just that the paramagnetic material he used was metallic tin.
The critical temperature of tin entering the superconducting state is 3 Kelvin, so Chen Muwu discovered the superconductivity of niobium, a paramagnetic material with a higher critical temperature, by accident earlier, which prepared him for today's experiment. Base.
After finishing his thoughts, Chen Muwu continued to be his assistant and asked Shi Ruwei and Oppenheimer to verify whether lead could float in the same way.
He felt that this simple practice should not cause any accidents, but as expected, accidents still occurred.
"Teacher Chen, the temperature has dropped to 5 Kelvin, but the lead pieces in the magnetic field still fail to float like niobium."
It was Oppenheimer who came running to report to him, with a panicked expression on his face.
"Really? Then I'll go take a look."
He stood up and walked to the machine. Looking at the piece of lead that was larger and thicker than the previous niobium, Chen Muwu's nose felt so hung up that he didn't get angry.
The magnetic field is still the same, but the metal has been changed from niobium to lead with a higher density.
Not only does the optical density increase, but the volume of the sample also increases.
It's hard to say whether that small magnetic field can produce a repulsive force that is enough to offset the lead piece, or even the gravity of the lead piece.
"Who found this sample?"
"It's me, Teacher Chen."
Just guess it.
Oppenheimer didn't know how to operate the machine, so he could only help Shi Ru with the fight. Unexpectedly, he couldn't even prepare samples.
"Let's find another piece of lead. The current sample is too big and too heavy. Otherwise, increase the magnetic field and try again."
It’s really not a worry, you have to teach yourself about this kind of thing.
Finally, after several improvements, the lead piece successfully floated in the magnetic field.
This new phenomenon also appears in diamagnetic lead, which means that this is not a unique phenomenon that only occurs in niobium, but should be applicable to all superconductors.
Next, it is time to design an experiment to detect the magnetic induction intensity inside the superconductor.
Shi Ruwei and Chen Muwu talked about how this experiment should be designed, and Oppenheimer was still "waving the flag and shouting" beside him.
Although he had a smile on his face, he kept telling himself in his heart that after the experiment came to an end, he must also learn about magnetism.
The experimental method that the two finally determined was to prepare two cylindrical superconductors and place them parallel to each other up and down, leaving only a small gap in the middle.
A search coil is then placed within the interval and the other end of the coil is connected to the impulse galvanometer.
Then record the readings on the galvanometer under two conditions, one above the critical temperature and one below the critical temperature, and compare them.
For Shi Ruwei and Oppenheimer, no one can say whether the experiment will succeed.
But in their hearts, they all hope that the experiment will succeed, because if it fails, they will have to find a new theoretical explanation for the floating phenomenon again, and redesign the experimental verification for the new theory.
But for Chen Muwu, this experiment was all about shooting the arrow first and then drawing the target, and it was destined to succeed.
The experimental results were exactly what he expected.
At this point, Chen Muwu's research work on low-temperature physics in the laboratory is all over. After writing the paper on this new effect, he will probably not be engaged in it again for more than ten or even twenty years. Study of low temperature physics.
In more than half a year, he invented plexiglass, earned enough funds for Swedish schools, and made two Nobel Prize-level discoveries about deuterium and superconductors' complete diamagnetism. Chen Muwu felt that this was quite worthwhile. some time.
Although his original intention of conducting research on low-temperature physics was just to try to distort the original technology tree.
Then he handed the paper to the editor-in-chief Gregory, and after walking out of the editorial office of "Nature" weekly, Chen Muwu dropped a letter he had prepared long ago into the mailbox.
His letter was the same as last time. In a very humble tone, he informed Yoshio Nishina that he was lucky enough to have made an inconspicuous achievement in superconductivity.
What Yoshio Nishina thought after reading the letter in the Netherlands was that it had nothing to do with Chen Muwu. Anyway, this time he was finally escaping from the bitter sea of low-temperature physics and returning to the embrace of particle research...
……?
Some people don't want this to happen.
Old Bragg was anxious when he learned that Chen Muwu had completed all the experiments at the Royal Institution and planned to leave London and return to Cambridge.
Now the name of Davy-Faraday Laboratory has become a household name throughout the UK, the laboratory has sufficient funds, and the new Mond Laboratory has also been selected and is about to start construction.
Old Prague is preparing to show off his talents and realize his great ambitions. At this juncture, Dr. Chen is leaving? This is absolutely impossible.
The Davy Faraday Laboratory was reborn because Old Bragg followed Chen Muwu's advice and vigorously promoted the development of low-temperature physics in the UK in newspapers.
The Monds laboratory under construction is also a specialized laboratory that mainly studies low-temperature physics.
The person with the highest level of low-temperature physics experiments in the UK is now known as Old Bragg in the hearts of the British.
But on a practical level, no one can surpass Chen Muwu.
If Dr. Chen were to return to Cambridge, wouldn't he be showing his cowardice?
As it happened, the new Monds laboratory was still short of a director.
If Chen Muwu stayed at the Cavendish Laboratory and wanted to become director, he would have to wait at least until Rutherford retired.
But looking at that old guy's body, it doesn't seem to be a problem for him to work for another twenty or thirty years.
Although you can’t retain the professorship at the University of London, can’t you still be retained by the position of director of the laboratory, which you always promise?
(End of chapter)
