Yesterday, I stayed up all night, and although I felt very tired, Junxin's spirit seemed to be more and more excited, so I didn't plan to go back to the dormitory to rest for a while, but thought of going to the classroom to take classes.

“… Crystals are one of the main objects of our study of structural chemistry, and we will focus on them in the following courses, including their properties and some special chemical effects......"

Well? Why is the style a little wrong? Although Junxin was in high spirits, after all, the whole person seemed a little tired, so he just came to this classroom in the direction of his memory, but after a while in a daze, when the teacher came in and started to lecture, Junxin suddenly found that he seemed, probably, maybe, maybe, must have gone to the wrong classroom! It's obviously a chemistry class.

"Forget it, the so-called once it comes, it will be safe. It's also good to change your brain once in a while! But if only it were a physics class! Jun recited silently in his confidence, and regardless of whether he went to the wrong classroom or not, he calmed down and began to listen to the teacher's lecture.

The professor on the podium noticed that there was an extra student in the class very early, but he didn't care much, he just thought that students from other departments or other classes had come to take the class, so he talked about it in an orderly manner according to his own ideas and preparations.

But soon the thing that made this insistent angry happened, it turned out that Junxin began to get sleepy when he listened to it (students who have studied all night may have had it), and unconsciously began to fight between the upper eyelids and the lower eyelids, after a long time, plus it is not his own discipline. So Junxin fell asleep on the table.

Now something big is going to happen!

You must know that today's universities have not expanded their enrollment like later universities, so there are not so many teachers in the universities, and most of the professors still take freshman courses. Professor Chen Hao is one of them.

After graduation, with the help and encouragement of his teachers, Professor Chen went to Heidelberg University in Germany to study chemistry for a master's degree and a doctorate, and graduated early in four years. However, because his research direction is structural chemistry, which is too basic, neither the Chinese Academy of Sciences nor the university has much research funds, and finally he was hired by the School of Chemistry of Mizuki University to serve as a professor.

Professor Chen is young and promising, although sometimes the things he learns are not used at all, at least at the current time when China pays more attention to applied research, there is little investment in the theoretical basis, but he can refuse the invitation of Heidelberg University to stay and teach and resolutely return to China, he still hopes to use his knowledge to make more contributions. At the same time, he also hopes to discover a few good seedlings and follow him to do research on the basis of theory. In his eyes, the basic things are sometimes the most fundamental things, which cannot be compensated for no matter how much technology there is.

To put it simply, ancient China didn't know how many brilliant technologies there were, but there was no corresponding theory, so technology was just a secret for a period of time, and after that, most of the secrets became mysteries forever! If there is a relevant theoretical basis at that time, then future generations will be able to know the ins and outs of these technologies, and it will be smooth to rediscover these technologies.

We will not analyze Professor Chen's thoughts for the time being, but the question now is that in Professor Chen's class, a student actually fell asleep in a dignified manner, what is the situation?

Mizuki University in the 80s was not what it was like in later generations, let alone the kind of third-rate universities that later generations were, and some people dared to sleep in class. Professor Chen's heart suddenly swelled up with a nameless fire.

But after all, it was a class now, so Professor Chen suppressed the nameless fire in his heart and continued to explain to the remaining students meticulously. From this point of view, Professor Chen is still quite a dedicated person. But after all, there are people who are angry, so when Professor Chen was about to end the whole class, he raised a question as an interaction: "Ladies and gentlemen, in the study of this class, we have defined the meaning of the material form of crystals, so now I want to ask, what is crystals?" Ask the student to stand up and answer. "The location where Professor Chen's whip is pointing is where Junxin sleeps. Since Junxin has always sat in the corner, it is only now that everyone finds out that someone is actually sleeping in class, and if it weren't for Mizuki's strict classroom discipline, I'm afraid it would have exploded immediately.

"The classmate next to him called him, we have limited time, don't delay everyone!" Although Professor Chen was smiling, he did not urge with a smile at all.

A boy sitting in front of Junxin turned his head and pushed Junxin, but found that he didn't respond, and then pushed him again and screamed, and finally woke him up.

But fortunately, Junxin has a good temper and doesn't have any anger to get up, so he sighed and looked at Professor Chen with innocent eyes. Professor Chen still smiled and repeated the question.

"Professor, I'm sorry, I'm not a chemistry student, I'm a mathematics student!" Jun Xin scratched his head and said in an innocent tone.

"Mathematics? How did you get here in the math department? Professor Chen suddenly felt a punch hit the air, and his eyes were slightly dazed.

"Well, that's really embarrassing, I was going to go to the math classroom, didn't I go to the wrong classroom!"

Well, the whole class suddenly burst into laughter, and at this time, some people recognized Jun Xinlai, after all, Jun Xin also made a sensational freshman speech on behalf of the freshmen at that time. This also made Professor Chen have to believe that Junxin was indeed a student of the Department of Mathematics, and he couldn't stop crying and laughing. It's the first time I've seen such a student after coming to Mizuki for so long. If Professor Chen knew some popular words in later generations, he would have sighed that he had seen a lot.

"But I can answer the professor's question!" Jun Xin shook his head, drove away the drowsiness in his head, and said in an affirmative tone.

"Oh? Let's talk about it. Professor Chen only thought that Junxin was looking for a staircase to come down, so he followed his meaning and asked him to answer.

"A crystal is a regular and orderly solid that is periodic in microscopic three-dimensional space!" Although Junxin said this definition, he remembered the concept of quasicrystals mentioned by Professor Dyson in his lecture on birds and frogs.

"That's a good answer, Junxin!" Professor Chen just wanted Jun Xin to sit down, but he heard Jun Xin continue: "But I slightly disagree with this definition, I think the full definition of crystal should be the sentence 'solid with obvious patterns in the diffraction pattern'. ”

Professor Chen immediately became interested, he did not show any authority, but decisively ended his thoughts and continued to let Junxin continue. Vaguely, he felt that what Jun Xin said would subvert a certain traditional cognition.

"I'm from the mathematics department, and although I ran to the wrong classroom, I still habitually start with mathematics to solve problems." Junxin first made a joke, and then continued, "In 1961, Mr. Wang Hao, a famous mathematical logician in China, proposed the problem of using puzzles of different shapes to cover the plane. Mathematicians have known that it is possible to fill a plane with a single-shaped puzzle, such as an arbitrarily shaped quadrilateral or a regular hexagon, but by increasing the variety of puzzle units, more ways to fill a plane can be constructed. Two years later, Wang Hao's student Robert Berger constructed a series of puzzle puzzles that were not cyclical. In 1976, Roger Penrose constructed a series of puzzles that required only two puzzles, and the patterns were created with five degrees of symmetry. ”

"What we know is that in classical crystallography, whether it is 14 Braffy lattices or 230 space groups, five symmetries are not allowed, because five symmetries will destroy the translational symmetry of the spatial lattice, that is, it is impossible to fill the two-dimensional plane with regular pentagons, and it is impossible to fill the three-dimensional space with icosahedron."

"From the concepts of mathematics and classical crystallography, the conclusion is reversed, and from my point of view, I am more inclined to mathematical reasoning, so I feel that there should be a crystal-like existence of matter with quintessential symmetry!" The more Jun Xin spoke, the more serious he became, and he said in the last word, "Therefore, the current concept of crystallography is inaccurate!" ”