Shang Yiyun didn't take these words to heart, he knew that the other party had no malicious intent.

In the laughter, the period before the lecture was also wiped out, and at this moment, a spirited old man walked in from outside the door, Shang Yiyun had seen this photo on the school's official website before, so he naturally knew who the other party was.

Professor Yang Qi stood behind the podium, and the noisy classroom instantly fell silent, and the professors who were able to give lectures at Kyoto University were all academic leaders.

The other party looked at the time and found that when the time was up, he began to speak, without a trace of muddy water.

"Neutrinos, also translated as neutrinos, are a kind of leptons, is one of the most basic particles in nature, commonly used in the symbol letter V to indicate that neutrinos are small, uncharged, can freely pass through the Earth, spin is 1/2, the mass is very light (some less than one millionth of an electron), moving at close to the speed of light, and the interaction with other matter is very weak. ”

At the beginning of the lecture, the definition of neutrinos was naturally introduced, and although 99% of the students in the classroom were students in the Faculty of Physics, these basic definitions were understood, but the lecture still had to be taught.

For this situation, Shang Yiyun has enough patience, but next, the content of Professor Yang Qi's lecture is becoming more and more profound, and he took out a notebook to record some more important content.

"Neutrinos are produced by various weak interactions between particles, and the slow speed of weak interactions is the main obstacle to the "proton-proton" reaction in stars, which explains why neutrinos can easily pass through ordinary matter without reacting......

While listening to the lecture and recording it, he used to be self-taught, and now the lecture is systematically about the knowledge of neutrinos, and suddenly, he heard something of interest, and hurriedly concentrated and listened carefully.

"There are two main applications of neutrinos. ”

"One of the possible applications is neutrino communication. Because the Earth star is spherical, and the surface buildings and terrain are occluded, electromagnetic wavelength transmission over long distances must be transmitted through communication satellites and ground stations. Neutrinos, on the other hand, can penetrate the Earth Star, and their loss is very small when they pass through the Earth Star, and the neutrinos that produce 1 billion electron volts with a high-energy accelerator only decay by one thousandth of the time they pass through the Earth Star, so they can be transmitted directly to Kyoto from South America using neutrino beams through the Earth Star. By modulating the neutrino beam, it is possible to contain useful information and communicate at any two points on the Earth without the need for expensive and complex satellites or microwave stations. ”

"The second application is neutrino Earth-star tomography, i.e., stratigraphic CT. The cross-section of the interaction between neutrinos and matter increases with the increase of neutrino energy, and the neutrino beam with an energy of more than one trillion electron volts generated by a high-energy accelerator is used to irradiate the stratum directionally, and the action with the stratum matter can produce local small "earthquakes", similar to seismic exploration, which can also explore the deep strata and scan the strata layer by layer. ”

The first possible application is the direction of his next research, and now there are certain results.

After listening to Professor Chen Qi's lecture and combining his self-taught knowledge, his understanding of neutrinos has improved a lot.

He didn't expect that this lecture would make such a big gain, which was something he hadn't expected before.

After the lecture, Shang Yiyun was stopped by a few friends from the School of Physics, who were about to invite him to a meal, and there was a month to go on vacation, and he didn't know if he had time later, so he moved forward for a while.

These friends were met when he was in class, and the beginning of their acquaintance was to discuss a problem, and in the later time, they often discussed, and they became very good friends.

"Well, we've known each other for so long, and we haven't eaten together yet, so we just have time today, so it's good to have a meal together. ”

Shang Yiyun did not refuse, these friends are some relatively good people, even if they are not as good as him, but compared to others, they can also be said to be the existence of academic tyrants.

In this world, it's good to have one more friend, maybe you may need the help of these people in the future.

The group came to a restaurant outside, and it was now nearly six o'clock, and it was almost time for dinner.

After opening a private room, everyone walked in, leaving one person to order food outside, plus Shang Yiyun A total of six people, all of whom are men from the north, so wine is indispensable, of course, wine is beer, so I ordered a box, twelve bottles.

Dinner and drink with friends, just have fun, two bottles per person is enough, this is not a drinking place to talk about business, just an ordinary dinner.

These people are mainly physics majors, and the students who can be admitted to the physics department of Kyoto University are all top students in various regions, and this point is more advantageous than students who are admitted to ordinary colleges and universities when they go to university.

It's dinner time now, naturally I won't talk about learning this kind of bad scenery, a few boys get together, it's easy to pull the topic to the girls, there are six people present, three of them have girlfriends, except for Shang Yiyun who started in high school, the other two are after the start of school.

Kyoto University's male-to-female ratio is 3:2, which is better than Huaqing University's 2:1, even if there are more men and fewer women, but as long as you pay attention, you still don't have to worry about being single, not to mention, there are some normal colleges near Kyoto University.

After chatting for a while, the meal was ready, the box of snow beer was also placed under the table, each person opened a bottle of beer, and began a series of activities such as toasting, two bottles of beer, for him, is nothing, but after eating this meal, he has to go back to rest, and he has to go to class tomorrow, so there is no need to drink too much.

"Shang Yiyun, what are you going to do in the future?"

In the process of eating, there was naturally no shortage of chats, and for this question, Shang Yiyun thought for a moment and said.

"I want to be a researcher in the future, and through this period of study, I believe that I will be able to achieve this goal. Speaking of this, Shang Yiyun seemed to exude a strong sense of confidence.

For Shang Yiyun's answer, others had expected it and were not surprised, after all, during this time, only Shang Yiyun, a liberal arts student, came to the School of Physics to take classes, and in terms of knowledge and ability, it was comparable to some old fritters who were three or four years old.

These people don't know the true level of Shang Yiyun, and now Shang Yiyun's knowledge level in physics has reached the doctoral level, which is comparable to some doctoral students.

Of course, his friends don't know about these situations, and if they do, they don't know how to be surprised, after all, Shang Yiyun is a first-year student like them.

Everyone thinks that it has been overestimated, but they can't think of it or underestimated.