The top student must be diligent.

Chapter 138 is probably about...finding the differences?

As soon as Xiao Yi said this, Luo Mingya, who was about to go about her own business, and Zhao Yuanyuan next to her were stunned.

You've only been looking at it for a while, and you've already concluded that Fourier transform is necessary?
Although they are all mathematical things, these data are also from their material science major, right?

Can you understand?

Luo Mingya stopped her feet and turned to look over: "What's the reason?"

Xiao Yi pointed to the graph and said, "You can see that the stress-strain curve of each sample contains many oscillations and fluctuations, and the curve of the abnormal sample shows different behavior from other samples."

"So it's easy for us to think of using Fourier transform to process it."

"After all, anyone who has studied Fourier transform should know that for this kind of curve oscillation, it is best to use Fourier transform to process it."

"Hmm...but there is too much data. It would be better to use a computer to process it."

Hearing Xiao Yi's words, Zhao Yuanyuan looked confused.

what?
Have it?

It turns out that the curve of the abnormal sample is so different from the curve of other samples?
Why didn't she see it?

Luo Mingya leaned forward to take a look, and after thinking for a moment, she said, "Indeed, there is indeed a clear difference."

She had never seen this data before, and after Zhao Yuanyuan gave it to her, she had not found the time to look at it.

She glanced at Zhao Yuanyuan and said, "Didn't you notice this?"

Zhao Yuanyuan was confused.

what?
Should I find out?

She whispered, "No, Senior Sister, I feel that judging from the curves, these lines are almost the same... at most, at most..."

"Okay, you don't need to be the most, just watch carefully and learn well."

Luo Mingya shook her head and thought, forget it, she decided not to explain it to the rookie.

Xiao Yi took another look at the curve and then said, "Let's first convert this data into signals in the time domain. In this way, these data should represent the mechanical response of this metal under different strain conditions."

"However, time domain signals are not enough, we also need to convert them to the frequency domain."

"This requires the help of a computer. I can't handle it alone."

Xiao Yi shrugged and said.

After all, there is too much data, and using a computer is obviously more convenient and labor-saving.

"The computers are in the computer room next door. Let's go there now." Luo Mingya acted decisively and walked in front to lead the way.

Zhao Yuanyuan quickly followed.

Of course, Xiao Yi followed.

However, what happened here also attracted the attention of other people in the laboratory, Xu Ming, Liu Chao, and another boy named Wen Xiping. They looked at each other and quickly followed.

When they arrived at the computer room, there was indeed a server here. After seeing it, Xiao Yi couldn't help but ask: "Don't you have a server? Why do you want to rent mine?"

Luo Mingya said: "This server is several years old, and it was only worth 70 yuan at the time. You have to wait in line to use it. What's more, the project we are working on will take a long time to run. This antique is not worth a dog."

Xiao Yi: "Uh..."

Zhao Yuanyuan whispered: "Senior Sister, it seems we need to use it now..."

Luo Mingya snorted: "I use it to give it face. What's more, the current topic is yours, so it's the same as you using it."

Zhao Yuanyuan could only shut up in disappointment. If she continued talking, her citizenship would be in jeopardy.

He turned on the computer and connected to the server. Then Luo Mingya retrieved the data and began to convert the data from the time domain to the frequency domain as Xiao Yi had said before. This is the spectrum diagram.

Xiao Yi looked at these curves carefully, and then pointed to a part of the curve representing the abnormal sample and said, "Obviously there is a very obvious specific frequency oscillation peak on this part."

Soon after, Luo Mingya also stretched out his hand, pointed at the curve of the normal samples and said: "The oscillation peaks of these normal samples are different from those of the abnormal samples, especially in this type of frequency."

The two people's words rang out one after another, and Luo Mingya raised her eyebrows and glanced at Xiao Yi.

Is it possible to achieve this level just by being good at math?
Even faster than her reaction?
The other people watching nearby were even more stunned.

The conclusions drawn by these two older brothers and sisters were already incomprehensible to them.

Can you really tell anything from the data chart above?
Are you kidding me?
Of course, putting this aside for now, what shocked them even more was that Xiao Yi actually reached the conclusion earlier than their senior sister?
Even though it was only a second or two earlier...

However, this was beyond their imagination.

Their invincible senior sister actually lost by a small margin? !

Can Xiao Yi understand these things just by relying on his mathematical ability?

They were starting to get a little numb.

"So what do you think these things represent?"

Not knowing what the rookies behind her were thinking, Luo Mingya asked Xiao Yi with great interest.

No matter how good you are at math, it's impossible to answer all these questions, right?
Of course, Xiao Yi couldn't give an accurate answer, but he thought about it and said, "It should mean that the internal units of this abnormal sample are different? Hmm... I have heard that there is something called lattice in the unit of materials. Maybe it is related to this?"

When she heard Xiao Yi say the word "lattice", Luo Mingya's eyes finally showed surprise. She took a deep look at this mathematical genius and said, "You have guessed it almost right. My inference is that these abnormal peaks may be related to lattice defects or dislocations in metal alloys."

Xiao Yi's eyes lit up: "It seems that I really guessed right."

Luo Mingya didn't say much, but turned to the junior brothers and sisters behind him and said, "I hope this case can give you some experience. For this kind of curve, we obviously have to think of using Fourier transform and spectrum analysis to study it."

"Especially for you, Zhao Yuanyuan. The data is very obvious. If you don't see it, it means you don't practice enough. I'll find five more papers for you to read later."

Zhao Yuanyuan: “Ah?”

"The next step is to further investigate using materials microscopy and X-ray diffraction experiments."

"Let's all go back to the lab and work."
Under Luo Mingya's command, no matter how much Zhao Yuanyuan wanted to cry, she had to quickly return to the laboratory and start her research.

Xiao Yi didn't know how to use it, so he just watched them use it.

Xu Ming and Liu Chao were also idle, standing aside, looking at Xiao Yi, and then asked: "Um... Brother Xiao, how did you see that just now?"

"That's how I figured it out." Xiao Yi said, "Probably... looking for differences?"

Find the difference!

(╯‵ ′)╯︵┻━┻

Xu Ming and Liu Chao looked embarrassed.

Liu Chao asked again: "Then...how did you come up with the idea of ​​lattice? Have you really never studied materials?"

Xiao Yi said, "I really haven't learned it. As I said just now, I just heard about the concept of lattice by chance, so I remembered it. As for why I guessed it... to use a rather distorted word, it can be roughly understood as calculus. The entire metal block is continuously divided into the smallest units, and the abnormal peak is almost equivalent to an abnormality in the smallest unit of calculus. Well, naturally it is related to the lattice."

Xu Ming, Liu Chao: "..."

Is this god-level mathematical thinking?

Xu Ming thought for a while, and suddenly his eyes lit up. He said, "Brother Xiao, I recently saw a question on the Internet that proves that the cube of π is greater than 31. If you were to do it, Brother Xiao..."

Before he could finish, Xiao Yi replied: "It is easy to observe that 3.1415 cubed is approximately equal to 31.0035, which is greater than 31."

The two were stunned. How could this be observed?

3.1415 times 3.1415 times 3.1415…
What a joke!
"Brother, please try another method. We can't do this mental arithmetic in our heads."

"Well..." Xiao Yi said, "Okay then."

Then he took out a small notebook and pen from his pocket and wrote on it:
"Yes, it is like that."

After Xiao Yi finished writing the formula, he tore off the paper and handed it to them.

After reading it, Xu Ming and Liu Chao were silent.

They realized that they shouldn't have been idle and come to Xiao Yi to do this kind of questions.

Isn't this just asking for trouble?

"I say, you guys are done. Do you look down on Xiao Shen by asking him to solve this kind of problem?"

At this time, Zhao Yuanyuan came over, jumping up and down, and she looked very happy: "Senior Sister has come to a conclusion. It is basically certain that it is a lattice defect problem."

"The senior sister also said that as long as we conduct further research on this problem and come up with some understanding of the mechanical behavior of metals, or optimization and improvement plans, maybe we can publish a first district!"

"Thank you, God Xiao! You helped me a lot!"

Zhao Yuanyuan bowed 90 degrees to Xiao Yi.

Xiao Yi quickly waved his hand: "No need to thank me, I just provided some mathematical help, the most important thing is that your senior sister saw the problem."

"You were the first to find out the problem!" Zhao Yuanyuan looked at Xiao Yi with admiration: "No matter what, I'll treat you to milk tea, and I'll treat you to a meal next time!"

"Ah, no need for dinner." Xiao Yi waved his hand: "Milk tea is fine."

"Well, okay!" Zhao Yuanyuan had no choice but to nod. Then she took out her cell phone and started ordering milk tea.

"Hey? Where are ours?" Xu Ming next to him winked and said, "After all, we have been fellow disciples for such a long time. We entered in the same year."

Zhao Yuanyuan glared at him: "Have you ever helped me?! Get out!"

"It's bad, Junior Brother Liu, we are strangers now. Your Senior Sister Yuanyuan..."

"Pia!"

A slap came from behind Xu Ming's head.

"What are you talking about here?" Luo Mingya pushed Xu Ming aside.

Xu Ming covered his head, stared at their senior sister with his eyes wide open, and dared not say a word.

Liu Chao, who was standing next to him, quickly hid aside, indicating that it had nothing to do with him.

Luo Mingya clapped his hands, then looked at Xiao Yi and said, "Junior Brother Xiao, it seems that with your ability, you can now officially enter our project."

"Our project aims to study the properties of defects in two-dimensional materials using density functional theory and first-principles calculations."

"If there is no problem, posting an NM or something, it's not a big problem."

(End of this chapter)