Back in 1978, I was admitted to Northwestern Polytechnical University.

Chapter 6 Senior Brother
"Senior brother, come in, come in quickly!"

Qin Liang, standing at the door, turned his head to look behind him, but there was no one there!

"Who are you two calling?"

"Hey, senior!" Zhu Yongguang greeted him. "Senior, thanks to your guidance in the cafeteria, we studied for half a day in the library this afternoon and finally caught up on this part of the knowledge!"

"Yeah, senior, you're amazing! You even know which page the knowledge is on!" Zhao Ergang came up and said, "Come on in! We didn't know you were in the same dorm as us, otherwise we would have treated you to a couple of meat dishes at the cafeteria tonight to welcome you back. Senior, which school did you graduate from?"

"Me? I graduated from Xiaohuangzhuang Middle School in Yan Province."

"We're not asking about your high school, we're asking about your university. Where did you go to university? It shouldn't be this university, right? I know the senior students in the aircraft engineering department. You must have come from another university to get into our Northwestern Polytechnical University for graduate studies, right? You're really talented."

"A university? Northwestern Polytechnical University!"

"Huh, that's strange. I've never seen you before."

"Of course, this is my first day here."

First day!
The two exchanged a glance, and an absurd thought popped into their minds: they had studied at Northwestern Polytechnical University, and this was only their first day here... This senior...

"Excuse me, what grade are you in?"

"I'll go to college when school starts."

Puff, puff!
The two of them plopped down on the bed next to them!
Is this student a freshman? Was the person who was giving those two aerodynamics pointers in the cafeteria today a freshman?

At this moment, Qin Liang had already walked to the lower bunk of his bed, pulled out a brand new washbasin, and intended to wash his face and feet. There was no other way; it was a habit he had developed in his later life—he had to wash before bed, otherwise he couldn't sleep.

In this era, dormitories didn't have bathrooms. On each floor, there was a communal washroom and toilet. Now, because it's the holidays, there aren't many people. But if school starts, the scene of countless people showering in the washroom and countless naked bodies running around the corridors, using washbasins to cover their private parts, would be quite a spectacular sight.

When Qin Liang returned after washing his face and feet, he saw his two roommates still standing there in a daze, and he couldn't help but feel a little curious.

These two guys are already seniors, and they should belong to the batch of students who were admitted through the worker-peasant-soldier recommendation program. Their academic level may be a bit low, and they can forget even the most basic aerodynamics as soon as they learn it. However, this situation will not occur in the future. After all, the spring of science has arrived, and getting into university is no longer based on family background or connections!

"Hey classmate, are you really a freshman?" The two senior students, who were still in shock, finally reacted and started asking when they saw Qin Liang return.

"Yes, my name is Qin Liang."

"Zhu Yongguang".

"Zhao Ergang".

After exchanging names, Zhu Yongguang said, "Qin Liang, you've only just entered university, how come you're so familiar with university-level knowledge?"

"Well, back when we were sent to the countryside, an old professor moved in next door to me..." Qin Liang could only repeat this explanation.

"Oh, I see. Indeed, no matter what, we should never give up learning; knowledge is power!"

"Qin Liang, our research today was very enlightening, so, so..."

"Senior, if there's anything I can help you with, just let me know!" "You know we have to write papers in our senior year, so I wrote one. Could you... show it to me?"

Qin Liang took the stack of manuscript paper that Zhu Yongguang handed over.

Analysis of induced drag in subsonic high angle-of-attack flight with delta wing configuration.

It has no abstract, no keywords, and no English content, so it's not a formal university graduation thesis at all. But these things don't matter; they can be added later. The key is the content.

Qin Liang flipped through the first page, then the second, then the third... He finished reading it in less than a minute, as perfunctory as could be.

"Qin Liang, is this paper...too bad?" Zhu Yongguang asked worriedly.

Qin Liang subconsciously wanted to nod, but then he felt that saying it would be too hurtful.

"Well, the key problem is that the formula is used incorrectly."

“That shouldn’t be the case. We’ve been studying the data all afternoon and believe that to study this induced drag analysis, we need to start with Stokes’ theorem,” Zhu Yongguang said.

“That’s right. Let Γ be a piecewise smooth directed curve in space, and ∑ be a piecewise smooth directed surface with a one-dimensional boundary. The positive direction of Γ and the side of ∑ conform to the right-hand rule. Functions P, Q, and R have continuous first-order partial derivatives on the surface ∑ and the boundary Γ, then…” Zhao Ergang then repeated what he had learned today, saying it again to reinforce his understanding.

"So, when you were looking up the formulas, did you find the Gaussian divergence theorem?"

"what is this?"

"This theorem describes the flux of a vector field through a surface as equal to the integral of the divergence at all points within the volume enclosed by the surface. The formula is..."

As Qin Liang spoke, he began writing down formulas rapidly and explained the uses of this theorem.

After Qin Liang had filled an entire page of manuscript, Zhu Yongguang finally realized: "Qin Liang, are you saying that the first half of the paper I have here is actually a proof of the Gaussian divergence theorem?"
"That's right, that's exactly it. The entire proof is basically correct, but using it as a thesis is a bit..."

"Luckily I didn't take it out. If I had shown it to Teacher Liu, he would definitely have scolded me..."

"Teacher Liu? Isn't Professor Sha your teacher?" Qin Liang asked curiously.

“Professor Sha is an aerodynamics major, and we are aircraft engineering majors,” Zhu Yongguang said. “It’s just that this summer, we stayed on campus instead of going home, and Professor Sha happened to be going to Factory 132, so he took us with him. He only came back this morning…”

Aircraft engineering, which is the same as aircraft design and engineering in later years, is simply the major that undertakes the specific work of designing aircraft. They certainly study aerodynamics, but it is only covered in one book and can be completed in one semester. They also need to study dynamics, propulsion, measurement and control, mechanics, and so on. Their foundation is not solid, and they learned aerodynamics two years ago, so they are somewhat lacking.

"Oh, what's Teacher Liu's name?"

"Liu Qiangang."

Qin Liang was overjoyed; he hadn't made a mistake coming. Professor Liu was indeed a big shot!
"By the way, for those of you doing mathematical physics research, the Green's function is a great thing. Have you ever thought about using this function in your papers?"

Thinking of Professor Liu, Qin Liang thought of the Green's function, so he mentioned it.

The two looked completely bewildered, as if they had heard of it somewhere before, but... they really couldn't remember!

(End of this chapter)