Chapter 296 Graduation

On the third day after receiving the Guo Award, Wu Bin ushered in his graduation defense.

In the defense room, Wu Bin was describing the thesis he had written.

"As mentioned above, the current highest transition temperature of iron-based superconductors has reached 55K, breaking through the Maclan limit of 39K, and has entered the range of super-temperature conductors. Although there are still shortcomings, but..."

Hearing this, Academician Chen Xianhui, who had been sitting quietly, suddenly asked: "Then what temperature do you think the iron-based superconductor will be able to achieve?"

Wu Bin, who was about to put the PPT down, was stunned after hearing this, thought for a moment and replied: "At least it must exceed the liquid nitrogen temperature of 77K."

After hearing this, Chen Xianhui nodded, moved a chair next to him, patted it and said, "Come and sit, I have already read your paper. In fact, it is very well written. I believe that your level does not require me to do it again." What verification, I would rather hear your understanding and understanding of superconductivity now."

"This..." Wu Bin scratched his hair, "I'm just getting started in superconductivity. I really feel a little unsure when it comes to understanding in front of Professor Chen."

You must know that Professor Chen Xianhui's group is currently at the forefront of iron-based superconductivity in the country, and it can definitely be said to be in the master category.

"Haha." Chen Xianhui laughed twice, "Don't be nervous, just say what you think."

"Okay, since you said so, Professor Chen, I will give it a try." Wu Bin finished speaking and sat next to Chen Xianhui, "Actually, after reading a lot of papers on high-temperature superconductivity, what I am most confused about is high-temperature superconductivity. What is the specific mechanism? Although the existence of long-range magnetic ordering phase in iron-based superconductivity is considered to be one of the possible causes of superconductivity, this is only a possibility and only one of them."

Chen Xianhui nodded, "Yes, because there are many complex phase diagrams such as charge density waves, spin density waves, long-range ferromagnetic antiferromagnetic superstructures in high-temperature superconductors, research on its mechanism has always been very difficult, so this is not only It’s just your doubts, it’s the doubts of the entire academic community.”

Hearing this, Wu Bin suddenly stood up and walked to the blackboard and wrote [SmFeAsO1-xFx] and [Ba1-xKxFe2As2] with chalk.

"I read a paper of yours before, which describes the study of the changes in superconducting critical temperature and spin density wave transition temperature in these two systems through the conversion of oxygen and iron. I found that the oxygen isotope at the critical temperature inside The effect is very small, but the iron isotope effect is very large."

"What's even more amazing is that the isotope exchange in this system has the same effect on the critical temperature and the spin density wave transition temperature. Does this mean that the electron-phonon interaction plays a certain role in superconductivity in this system?"

"Hahaha." Chen Xianhui suddenly laughed loudly after hearing Wu Bin's question, "No wonder Professor Liu took special care of me and told me not to believe what you said. I only understand a little bit, and I don't understand much of this kind of thing. "

"The fact that you can ask this question means that you are not at all as familiar with superconductivity as you said, and you are just getting started."

"Ah? Is this what Professor Liu said about me?" Wu Bin's expression was slightly embarrassed. These days, even if you speak cautiously, you will be criticized.

Seeing Wu Bin's embarrassed expression, Academician Chen Xianhui waved his hand and said: "It is a good thing to remain in awe in the face of knowledge. Those who like to talk all the time are the ones who really don't understand. I appreciate your quality."

"Thank you Professor Chen for your compliment."

"As for the question you just raised, this is actually not just a simple electron-phonon interaction mechanism. There may also be coupling between spin and phonons..."

When talking about rising, Professor Chen Xianhui also walked to the blackboard, picked up the chalk and started to draw a relationship diagram.

…

Outside the defense room, Jin Yunxia was waiting anxiously, grabbing Wu Shiqiang beside her from time to time and whispering: "Why hasn't it come out yet? Didn't my son just say it won't take long? Is there something wrong?"

Because Director Jiang told Wu Bin that the school would hold a graduation ceremony for him as soon as his graduation defense was over, so Wu Bin simply asked his parents to live next to the school for two days and attend the graduation ceremony before going back.

After Jin Yunxia heard the news that Wu Bin was going to defend his graduation today, she insisted on coming together, so she waited at the door of the defense room.

After hearing this, Wu Shiqiang patted her on the back and said, "Oh, don't worry. If your son says it's okay, it will be okay. Just believe him."

"That's what I say...but it's been too long."

At this time, Li Yan, who was also waiting on the side, smiled and said: "Don't worry, auntie, the defense will take a long time, which only means that they have a lot to talk about, and the defense tutor will not think about dissatisfied students. Talked to them a lot.”

After hearing this, Jin Yunxia patted her chest and said, "Then I'm relieved. Thank you, little classmate, I remember your name is... Li Yan, right?"

"Yes, it's me." Li Yan nodded.

"Thank you for taking such good care of my son at school and even coming here to wait for his defense."

"Auntie, your son is the one who takes care of me. He has helped me a lot. I am just his follower."

"Ouch, you can't say that. It's necessary for classmates to help each other. What kind of follower doesn't follow the follower?" Jin Yunxia smiled and waved her hand, then looked at Lin Ziqi, who had been standing silently next to Li Yan, and said, "Well... …Auntie’s memory is not very good. Have we met this classmate somewhere?”

Lin Ziqi, who was asked, immediately stood up straight and nodded: "Yeah! We met at the entrance of the library when Auntie came to see Wu Bin last summer vacation."

"Oh~~Yes, I remembered it." Jin Yunxia patted her forehead: "Look at my memory, but you seem to be different from that time?"

After hearing this, Lin Ziqi lowered her head and said, "Maybe it's because I was wearing glasses at that time."

"Yes, yes." After finishing speaking, Jin Yunxia approached Lin Ziqi and looked at her: "It's better not to wear glasses. What a pretty girl."

"Thank...thank you, auntie." Lin Ziqi said with a blushing face.

"Thank you for coming all the way to wait for Wu Bin. I feel relieved knowing that he has so many friends in school."

Lin Ziqi hurriedly waved her hands and said: "You're welcome, you're welcome."

Just when Jin Yunxia wanted to ask something else, the door of the defense room suddenly opened, and Wu Bin and Professor Chen Xianhui walked out of it.

Looking at the people waiting outside the door, Wu Bin smiled and said, "Everyone, I graduated."

Only then did Jin Yunxia feel relieved. She excitedly went up to hug Wu Bin and then bowed to Professor Chen Xianhui: "Thank you, teacher, thank you teacher."

Chen Xianhui quickly supported Jin Yunxia and said, "No need to thank me. Your son is very good. His ability to pass the defense has nothing to do with me."

"Thank you, thank you." Jin Yunxia nodded happily.

PS: I found out that it happened to be Chapter 300 ~ Spreading Flowers