The three roommates chose the position in the corner of the classroom, leaving an empty seat for Zhang Yi next to it, and he went directly to sit down.

Zhang Yi, who hadn't listened to a class for a long time, originally planned to re-experience the feeling of being a student, but after listening to it for a while, he felt very bored.

But what the teacher said was still too simple for him, so he didn't have the desire to listen, and he fell asleep while listening.

Jingle Bell ...... Zhang Yi woke up after the class bell rang several times, and he slept a little deeply, and he had the impression that he had not slept such a beautiful sleep for a long time.

For a period of time before he was reborn, Zhang Yi got up early and worked on projects every day, sleeping for less than four hours a day, and he didn't sleep well.

Now in school, and the identity of a student, the pressure on Zhang Yi's body is gone in an instant, although this sleep is very short, but after waking up, Zhang Yi feels refreshed and energetic.

After only one class, Zhang Yi found an excuse and skipped class again.

In Zhang Yi's view, class is to learn knowledge, and since he understands all these things, there is no need to waste time in the classroom.

It's not good to have this time.

Zhang Yi didn't go to the last class, and threw the book directly to Li Guohua and asked him to take it back from school, and he went out of the classroom alone.

After leaving the classroom, Zhang Yi walked around the campus for a while, it was now May, this time should have been just after spring, the season of recovery, but in Jiangcheng, the asphalt road has been steaming in a heat wave, walking on the road is similar to being in a steamer, and there are few pedestrians to be found as far as the eye can see.

Zhang Yi was already sweating after walking for a few minutes, so he could only walk in the shade of a tree as much as possible.

It's really hot! It's worthy of the four major stoves, this is the rhythm of roasting people to dry people.

Zhang Yi grabbed the neckline that was already soaked in sweat and trembled, and said in his heart that wouldn't it be nice if there was a bottle of cold sour plum soup!

Thinking of doing it and judging the next direction, Zhang Yi walked to the store under the scorching sun.

After buying a bottle of sour plum soup drink, Zhang Yi couldn't wait to unscrew the cap of the bottle and pour himself a sip.

Call...... Refreshing!

It's so refreshing to the heart, liver, spleen, lungs and kidneys!

"Hey, isn't this Zhang Xiaoshuai?"

Just as Zhang Yi smashed the bar and smashed his mouth to reminisce about the iced sour plum soup that had just touched his heart, a voice came out from the side.

Zhang Yi turned his head and saw that it was his high school classmate Ning Que, and immediately laughed: "Ah, isn't this a little lack of virtue?"

Ning Que and Zhang Yi are high school classmates, and the two were admitted to the same university in the college entrance examination, but Zhang Yi studied mining, while Ning Que studied materials. Because they left their hometown to go to college in other places, Zhang Yi and Ning Que had a good personal relationship, and they often went to high school reunions in Jiangcheng together.

When I was in high school, I liked to give my classmates nicknames, and their high school homeroom teacher was also surnamed Zhang, not only humorous but also very handsome, female classmates privately liked to call the homeroom teacher "Zhang Dashuai", Zhang Yi had good grades in high school, and was deeply loved by "Zhang Dashuai", and later I didn't know who gave him a nickname called "Zhang Xiaoshuai".

At this time, Ning Que was holding a large pile of documents in his hand, which looked more than ten centimeters tall, thinking that he had just come out of the printing room next to the small shop, Zhang Yi hurriedly took half of them and asked, "Why are you printing so many materials?"

With Zhang Yi helping to share half of the burden, Ning Que suddenly felt a lot more relaxed, raised his arm and wiped the sweat with the clothes on his shoulder, took a breath and said, "You don't know, I've been tired in the past few days." That's a lot of material to print right now. ”

"What's the situation?" Zhang Yi wondered.

"Hey, don't mention it. Ning Que shook his head and said, "You know, I followed Professor Li Ze of our department to do a project of the Natural Science Foundation, and this project has been established for more than 1 year now, and I have been worried about it recently." ”

Although Ning Que has been wiping his sweat and looks out of breath, his face is still happy when he talks about doing projects with professors, it is not easy for undergraduates to enter the laboratory, and they must be good enough.

Zhang Yi had just been approved to enter the laboratory, and it was obvious that Ning Que had been working in the laboratory for a while, and he also felt quite face-saving in front of his old classmates.

"What's wrong with that?

Ning Que sighed and said: "Yes, last month, the project was pre-defended once, but it didn't pass, and the indicators were unqualified, and then Professor Li gave a death order, and the entire research group was mobilized to redo the experiment and write the materials, but seeing that the final defense date was approaching, there was no progress." ”

"Oh, what exactly are you working on? Tell me, maybe I can help. Hearing this, Zhang Yi suddenly became interested.

"Cut, you can pull it down, you are a mining student, can understand materials? Materials are university subjects, not mining can be compared. Zhang Yi said that he could help, Ning Que immediately laughed, even the professor of materials science can't figure it out, he is an undergraduate, not studying materials but mining, what can he do.

Zhang Yi didn't mind, and said with a faint smile: "What's the matter, let me tell you, in more than ten years, the boundaries of these majors will not be so obvious, do you understand the interdisciplinarity? ”

Ning Que pursed his lips and said, "Then you can't do it, learn your mining industry hard, do you know the core material of sunscreen? It is a material that can absorb ultraviolet rays and prevent tanning and whitening." ”

In Ning Que's view, it is obvious that the material discipline is higher, like Zhang Yixue's mining is very down-to-earth, just like Audi and Alto, which is completely incomparable, anyway, Zhang Yi doesn't understand, and it's not a big deal to brag with his old classmates.

"Haha, what's so difficult about sunscreen materials, these are not all pediatrics. A hint of cunning flashed in Zhang Yi's eyes, and he touched Ning Que with his shoulder and said: "Hey, let's do it, if I understand this, you can invite me to a big meal, and when the time comes, call Xiaohu and a few of them, if I don't understand, I'll please, the one who wins the place is determined, how about it?"

Xiaohu is also their high school classmate, and the university is also a school, but the majors are different, and the high school classmates usually have any activities, and they all like to get together.

In fact, at the beginning, Ning Que said that the material project, Zhang Yi was still a little empty in his heart, even after more than ten years of high integration of various disciplines, the boundaries between disciplines have gradually blurred, but after all, materials are materials, mining is mining after all, Zhang Yi's understanding of materials may not be as good as some of the current professors.

However, even if he has not studied the topic of material types in depth, he still knows very well the development direction of some materials that became popular in the scientific research community, even if he cannot immediately solve the problems encountered in scientific research, but often an idea and a direction are enough to make the research go on the right path, and finally get the results smoothly.

However, the core materials of sunscreen that Ning Que said, it just so happened that he had done such a project, and the materials used were minerals, which was a small project of mineral materials that he did when he was a doctoral student at the University of Queensland, and he told Ning Que that doing this pediatric was really not bragging.

"Okay, okay, then I have to think about where to eat, it's your own gambling contract, don't blame me for killing you when the time comes." Sure enough, as soon as Zhang Yi's voice fell, Ning Que agreed without hesitation, but when he turned his head and thought about Ning Que, he felt that something was wrong, but don't be Zhang Yi fooling him, so he immediately changed his words and said: "But let's say okay first, you can't just say that you understand and just say the definition casually, that's not called understanding, at most it's called understanding, then I don't admit it, you have to convince me." ”

Ning Que didn't believe Zhang Yi at all, let alone gambling on a meal, even if he gambled on a semester's meal, he didn't frown, but for fear that Zhang Yi would fool him, Ning Que hurriedly set the rules first, otherwise Zhang Yi would be the one who suffered.

"Convincing??haha, I'm afraid you're going to throw yourself to the ground. Zhang Yi leaned closer to Ning Que's ear and said mysteriously: "I just pinched my fingers and counted, I know what materials you used to do this project." ”

Ning Que said in disbelief: "Do you know the materials we are studying? ”

Zhang Yi said lightly: "The materials for your experiments are nothing more than titanium dioxide, zinc oxide, and iron oxide at the very least, this is not a secret, at most these materials are made to the nano level." ”

It is indeed no secret that after 94 years, the focus of attention is on how to use the discovered physical and chemical properties of nanomaterials to design nanocomposites, and the synthesis and physical properties of composite materials have become the leading direction of nanomaterials research.

In 98 years, nanomaterials had just begun to rise in China, and many materials experts were eager to make nanomaterials into everything and then study their properties, which later caused "nano" to become a word on the bad street.

And the core sunscreen additives of sunscreens have also begun to move towards the road of nanologization.

Normally, sunscreens are divided into organic and inorganic, organic sunscreens include aminobenzoic acid, dibenzoylmethane and camphor derivatives, etc., and inorganic sunscreens are usually titanium dioxide and zinc oxide.

Ning Que is a materials major, and his natural research is titanium dioxide and zinc oxide, but Zhang Yi is not sure whether Ning Que's teacher is studying nanomaterials.

"Hold the grass, you really know. The material in Ning Que's hand fell to the ground with a plop, and his mouth opened wide.