Chapter 75: Xu Qingzhou Isn

Time gradually passed; the noon sun filtered through the leaves, casting dappled shadows on the lawn outside the window, while a gentle breeze stirred, carrying two dry leaves drifting down.

Throughout the entire morning, Xu Qingzhou completed the preliminary organization of existing data and used Python to clean the latest set of sample data.

During this time, Gong Yun came by once but, seeing Xu Qingzhou deeply absorbed, did not disturb him.

“Young brother, take a break and go eat.”

Hong Yayu’s voice pulled Xu Qingzhou back; he turned and saw that Hong Yayu had already taken off her lab coat.

Xu Qingzhou stretched and said, “Senior sister, I’d like to take these data back to study slowly.”

Hong Yayu nodded, pointing to the hard drive beside her, “You can copy it here, but the computational load is heavy—it’s demanding on the computer’s configuration.”

For new students, besides military training, the second thing is joining clubs.

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“Xiao Qiong?” The voice was cool and clear.

Zhang Qiong reacted quickly, making an excuse: “Yeah, rice with meat. I suddenly felt like eating what you’re eating.”

“I didn’t see who it was,” Xu Qingzhou said helplessly.

The campus was lively; the Triangle Ground in Yanyuan was hosting club recruitment, in full swing, commonly called the Hundred Clubs War—Xu Qingzhou had no real interest in it.

Use the sigmoid function (logistic function) to describe how resistance changes with temperature: it is a continuous function with an ever-increasing rate of change, exhibiting an “S”-shaped curve that effectively models the transition from normal state to superconducting state.

Xu Qingzhou now understood why Hong Yayu had suddenly invited him to eat—she’d come to show concern, just as Gong Yun had said: though this senior sister seemed cold, she was actually quite thoughtful.

“Didn’t you go get rice with meat?” Song Yao asked, puzzled. Zhang Qiong’s expression was too strange—first fiercely hostile, like a villain, then as if caught doing something wrong.

This is the second one already! One Song Yao wasn’t enough—constantly flirting, and now, only a few days later, another girl! Zhang Qiong gritted her teeth, opened the photo she’d just taken, stared at the boy in it, her gaze darkening: Xu the scoundrel, wait and see—I’ll expose you for what you are, and you’ll die without even a grave!

Xu Qingzhou glanced again, baffled—or had he become so handsome that girls were secretly photographing him? Neither of them gave the incident another thought; after eating, they returned directly to the lab.

Hong Yayu ate while barely paying attention to who it was, merely adding, “She was just taking pictures of us.”

“I’ll have beef noodle soup too,” Xu Qingzhou smiled and nodded; the beef noodle soup at Cafeteria Five really was good.

So Song Yao and Zhong Ruotong went ahead and sat down to wait for Zhang Qiong.

Xu Qingzhou turned in confusion and saw a figure fleeing like a hunted animal, vanishing around the corner—it seemed familiar, but he couldn’t recall who it was.

“Let’s go eat beef noodle soup at Cafeteria Five,” Hong Yayu said, then added, “Of course, you can eat something else.”

“Right.”

After a while, Zhang Qiong came over with her tray and sat beside Song Yao, unable to help asking, “Xiao Yao, why haven’t you gone to see Xu Qingzhou these past two days?”

After two afternoon classes and dinner, Xu Qingzhou declined Xu Zhengyang’s invitation to visit the Triangle Ground, found an empty classroom, spent two hours finishing his paper, filled in the details, and clicked submit directly to Physics Reports.

Zhang Qiong felt a pang of sympathy, sighing inwardly: he must be busy—busy dating other girls again.

“Is this your first research project?”

Hong Yayu spoke little, giving a slight nod, leading Xu Qingzhou across Zhongguancun North Street nearby.

Hong Yayu suddenly looked behind Xu Qingzhou and asked, “That girl… do you know her?” At the same moment, around the corner of the cafeteria, Zhang Qiong patted her chest, relieved: close call—almost caught.

“Senior sister, where are we eating?”

Song Yao sighed, “I don’t really want to join any clubs.”

She glanced sideways and saw the two had already left. Xu Qingzhou was eating with another girl again!

!.

Only after finishing the paper did he pull out the lab data.

“Yeah, he went out to eat while you were looking at the data.”

“He?” Song Yao paused her chopsticks, her expression slightly melancholy: “He’s been busy lately—I don’t want to bother him.”

Hong Yayu nodded slightly, giving him a look that said, “You know good stuff,” walked a few steps, then asked, “You looked at the experimental data today—what do you think?”

At 11 p.m., before the manager came to evict them, Xu Qingzhou had preliminarily built a simple mathematical model.

“Good,” Zhang Qiong nodded with a smile.

“Then go quickly—we’ll wait for you over there,” Song Yao pointed to an empty seat nearby.

“Huh?” Zhang Qiong startled, quickly hiding her phone behind her back, nervously staring at the pretty girl across from her.

The morning started well, and the rest went smoothly.

“Does Senior Brother Gong still need to monitor the experiment?”

“Lately, so many upperclassmen have been inviting Xiao Yao—I’m even getting a headache,” Zhang Qiong complained.

As the two nearly finished eating, the cafeteria grew busier; by 12:10 p.m., students were returning from class.

“Have you decided which clubs to join?” Zhong Ruotong brought up another topic.

Xiao Yao has too little romantic experience—she was easily tricked by Xu the scoundrel. Looking at the beautiful girl beside her, Zhang Qiong grew even more convinced Xu Qingzhou was inhuman: how could he possibly deceive such a wonderful girl?

They chatted idly, entering Cafeteria Five before class ended.

“Alright, I understand,” Xu Qingzhou nodded; his computer cost 15,000 yuan—it could handle the data easily. He connected it, copied the data, and walked out of the lab with Hong Yayu.

Hong Yayu had no pretensions—she ate even more than Xu Qingzhou: one bowl of beef noodle soup, three fried buns, and even a guokui.

He said, “Harder than pure math problems, but I already have some ideas.”

“You’re impressive.”

Simultaneously, he constructed an equation model dependent on magnetic field strength and temperature.

Then he fitted the model parameters and input the data for verification.

Using Python, he calculated the critical current density under magnetic field strength: def critical_current_density(b, j0=1e10, bc=10, n=2): Since it was only a preliminary model, the first verification showed noticeable discrepancies from actual measurements—further data input would be needed to refine and improve it.

This was precisely why Professor Zhao Shengwen had sought help from the School of Mathematics: even a small model required complex computation, let alone a full-scale model capable of describing niobium-titanium alloy properties.

(End of Chapter)