I am a wall flower in Kuai Chuanwen

Chapter 244 Chapter 245 Retrieving Fingerprints
Before Sang Yu could finish his sentence, Cheng Ruichi interrupted, with a faint smile on Cheng Ruichi's face, "Come in with me."

Sang Yu: "...?"

Sang Yu was stunned for a moment and came back to her senses, then smiled and nodded at Cheng Ruichi, "Thank you senior!"

After Sang Yu went in, she realized that the laboratory of Jiangcheng University was really big, and all the living facilities were available.

Cheng Ruichi took a piece of clothing for the experiment and handed it to Sang Yu. After taking it, Sang Yu nodded slightly to Cheng Ruichi and said thank you.

Cheng Ruichi: "I'll prepare for you if you need anything."

Sang Yu glanced at the table, and then said to Cheng Ruichi, "Senior, please help me prepare a pair of tweezers, a pair of disposable gloves, a bottle of silver nitrate solution, a piece of clean white paper, and a daylight lamp."

Cheng Ruichi nodded, and put these three things on Sang Yu's table.

Sang Yu: "Thank you senior!"

Cheng Ruichi: "You're welcome!"

Sang Yu put on the test clothes, put on disposable gloves, and took out the fixing needle and silk thread wrapped in tissue paper from the pocket.

Sang Yu unfolded the paper towel, then spread it flat on the white paper with tweezers holding the silk thread, and placed the round end of the fixing pin on the paper.

Cheng Ruichi looked at the two things that Sang Yu placed, a very thin silk thread and a blood-stained pin.

Cheng Ruichi glanced at Sang Yu in confusion. What is Sang Yu going to do with these things in the laboratory?
Sang Yu took the silver nitrate solution at hand, took the silk thread and the fixing pin and sprayed it, then continued to spread it on the white paper, and then took the fluorescent lamp to shine on the top of the white paper where these two things were placed.

Cheng Ruichi watched Sang Yu's operation quietly. Sang Yu was very skilled in all kinds of movements, and he didn't think he was someone who had never been in contact with these things.

Cheng Ruichi was very surprised. Sang Yu obviously chose the Department of Literature, so why was he so clear about science.

Also, no matter how you look at it, this method is a bit like the fingerprint collection method used by the police station to collect evidence.

Cheng Ruichi only saw it once in a book, and never actually saw anyone operate it.

And he is a liberal arts student who seems to know nothing about physics.

After about ten minutes, Sang Yu took a look at the white paper, and there was a brown-black mark. She took a look, and then a slight smile appeared on her face.

Sang Yu turned off the sunlight light switch, then wrapped the fixing pin and silk thread with tissue paper, and put the white paper into the plastic bag together.

Sang Yu packed the tweezers and other things together, raised her head, and saw Cheng Ruichi looking at her in surprise.

Sang Yu was stunned for a moment, then nodded slightly to Cheng Ruichi, and said with a light smile: "Senior, I've used it up, I really trouble you today."

Sang Yu said as he put the plastic bag into the pocket of his clothes.

Cheng Ruichi looked at Sang Yu with a slightly stagnant expression, and then asked with some doubts, "Sister Sang Yu, were you taking fingerprints just now?"

Sang Yu froze for a moment, then nodded, "Yeah."

Using Cheng Ruichi's laboratory, Cheng Ruichi also majored in physics, and Sang Yu felt that even if she wanted to hide it from him, it would be impossible.

Spray silver nitrate solution on the fingerprints, and the sodium chloride on the fingerprints will be converted into insoluble silver chloride.After being irradiated by sunlight, silver chloride decomposes into fine silver particles, which will show brown-black fingerprints like a photo studio film, which is a common method in criminal investigation.This method detects fingerprints from a longer period of time.

Sang Yu had no choice but to go outside immediately. Fortunately, the laboratory of Jiangcheng University had all these things.

Cheng Ruichi looked at Sang Yu and nodded, then asked, "Then what is the use of your fingerprints?"

Sang Yu didn't speak, Cheng Ruichi felt that it was usually used to get fingerprints, so something serious must have happened.

He asked anxiously again: "Sister Sangyu, are you in any trouble?"

Sang Yu calmly shook her head, "No, it's not me."

Cheng Ruichi looked at Sangyu who didn't want to answer, and felt that he seemed to be asking too much, so he changed the subject again, "Sister Sangyu, how do you feel about your military training? Are you still used to it?"

Sang Yu smiled lightly and said, "It's okay."

Cheng Ruichi smiled modestly, "You are a girl, the military training is so intense, you have to take good care of yourself and don't make yourself too tired."

Sang Yu glanced at Cheng Ruichi's modest and polite smile, nodded lightly, and said with a polite smile: "Well, I will pay attention, thank you senior for your concern."

At this point, Sang Yu took off the disposable gloves and threw them into the trash can at his feet, then raised his head and smiled at Cheng Ruichi, and said, "Senior, I'm sorry to trouble you today, and I'll ask you to wait until the military training is over another day." Have a meal."

Cheng Ruichi paused for a moment with the hand holding the tweezers, then nodded, "OK."

Sang Yu took off the lab coat, looked around, and wanted to find a place to put it. At this time, Cheng Ruichi took the lab coat from Sang Yu naturally, "Let me do it."

Sang Yu: "...?"

Sang Yu handed him the clothes, "Then I will trouble you senior."

Cheng Ruichi still had a gentle smile on his face, "Sister Sangyu, don't be so polite to me."

Cheng Ruichi turned around and hung the clothes on the wall, and looked back at Sang Yu again.

He found that Sang Yu's collar was not turned up properly at this time, so he stretched out his hand and approached Sang Yu, ready to help her tidy it up.

Sang Yu felt Cheng Ruichi's hand stretched out in front of her, and subconsciously took a step back.

Cheng Ruichi's fingers just reached into the air and stopped.

The scene was slightly embarrassing. Cheng Ruichi also knew that Sang Yu was a quiet person who rarely interacted with people and seldom talked. Although they had known each other for a long time, except for Sang Yu who usually went to the library to borrow books and read books, there was nothing between them. Sang Yu seldom spoke to him except for a brief exchange between them.

This time, Sang Yu took the initiative to ask him for help, and he was quite happy in his heart. Perhaps, this could be regarded as a further contact with Sang Yu.

From the first time Cheng Ruichi saw Sang Yu, he felt that this elementary school girl was different from the girls he knew. She likes to be quiet and looks a bit mummified. She is not the kind of girl who feels amazing at a glance, but There was another indescribable feeling about her.

That kind of feeling is very subtle. Even though she didn't do anything, it always makes people want to get close to her.

Invisibly, Cheng Ruichi had already been deeply attracted by this temperament of Sang Yu.

(End of this chapter)