Chapter 18 second quarter

After the establishment of the Department of Physics of Tsinghua University, Wu Youxun was the first professor hired by Ye Qisun. Wu Youxun, a native of Gaoan County, Jiangxi Province, was born on April 2, 1897. He graduated from Nanjing Higher Normal School in 1920. There is no information to show what caused Ye Qisun and Wu Youxun to hit it off so well.Before going to university, the two had never met each other. One was in the North Country and the other was in the South of the Yangtze River. They were like two spinning tops rotating along different centers. Although the diligence and effort were the same, and the imprints of geniuses were similar, they each drew their own circles. It is difficult to meet or meet at a certain point.

But judging from Wu Youxun's path of studying abroad, it is also very suspicious to say that the two do not know each other face to face.Because Wu Youxun's study route is exactly the same as Ye Qisun's choice back then, it can be said that he followed suit.Ye Qisun walked ahead, and Wu Youxun followed behind. The result of this follow-up was that both of them created their own legends. In terms of age, Wu Youxun is one year older than Ye Qisun, but academically, Ye Qisun is two years earlier than Wu Youxun. Perhaps we will find the reason why Wu Youxun followed Ye Qisun at this point.When Ye Qisun was studying in the Department of Physics in Chicago, USA, Wu Youxun was looking forward to it in China.Perhaps Ye Qisun's first good news from the other side of the ocean knocked on Wu Youxun's heart, or maybe Ye Qisun had become a legend in Tsinghua University, so Wu Youxun, who was calm and spiritual, quietly remembered his signpost of success.This may be the explanation for why the two people's experience of studying in the United States is so similar.

Ye Qisun knew Wu Youxun's name when he was about to study for a doctorate at Harvard.The reason why Wu Youxun became famous among the students studying in the United States was that he devoted his life to experiments, and in just a few months, more than 20 x-ray tubes were worn out.Later, he and his teacher Compton successively published a series of papers that caused a sensation in the world of physics, and successfully verified the Compton effect.The discovery of the Compton effect was a turning point in the development of modern physics. It made the physics community finally confirm the reality of light quanta, which had a major impact on the establishment and development of quantum mechanics. In November 1925, at the 135th meeting of the Physical Society held in the United States, Wu Youxun was arranged to read their paper at the first place in the meeting.For this, Compton won the Nobel Prize in Physics.

Among Tsinghua students studying in the United States, Ye Qisun and Wu Youxun were the ones who won the world's reputation in the physics field at that time.They bloomed like a parallel lotus on the other side of the ocean, and then returned to China one after another, still choosing the same path. Mr. Compton is well aware of Wu Youxun's great contribution to the Compton effect.After the publication of the Compton effect, because it was difficult to prove, in the past few years, various theories came in from the physics community, which put him in a very embarrassing situation for a while.In the scientific world, what scientists value most is the spirit of science. If a discovery cannot be proved, just like a historian citing historical materials without a source, it will be labeled as a forgery, and it will be laughed at and criticized by others.As a university professor, Mr. Compton is at the University of Chicago, which is known for its rigorous academic research. If he lives under strange eyes every day, he will sooner or later become exhausted.Fortunately, his student Wu Youxun rescued him with his bravery and tenacity.Although he is only a student and unknown; although he is very young, only in his twenties, he sprints boldly to the difficult problems again and again. How many times, Compton dare not look at his bloodshot eyes.What is even more commendable is that God gave this young man a wise mind.He is not reckless, in the protracted tug-of-war, every retreat is like the prelude to an attack.Compton's self-feeling was as if a person in a tight siege suddenly heard the shout of reinforcements, and it was this voice that gave Compton confidence and determination to regroup. Finally, their master and apprentice teamed up to win the experiment .

There are many students in Compton, why Wu Youxun? After various investigations, Compton came to the conclusion that this person is a rare talent in the field of physical science. Especially after he won the Nobel Prize in Physics, he knew in his heart that this award would change his destiny, and this award, in a sense, was given to him by his student Wu Youxun. When he learned that Wu Youxun was going back to China, Compton several times persuaded him to stay or let him find a better job for him.Compton was emotional.In order to prove that what he said was true, the employer he contacted entangled Wu Youxun like a cloud chasing the moon.However, Wu Youxun declined all of them.He wants to go back to his motherland to complete a mission that can only be completed in his whole life.

This is the way to save the country through science. It is this great mission that brought Ye Qisun and Wu Youxun together. After Wu Youxun returned to China, he successively taught at Datong University, Jiangxi University, Nanjing University, and Fourth Sun Yat-Sen University.In just over a year, he changed schools several times, feeling somewhat hasty.Why?There is a saying that "a good bird chooses branches to live in", he is looking for and choosing. He does not choose the salary level, nor is he looking for good treatment.He was looking for an environment where he could conduct scientific research and a laboratory that satisfied him.

Meanwhile he was waiting.Waiting for the confidant in life to appear, just like Yu Boya was looking forward to Zhong Ziqi back then. Finally, the day has come. When Mr. Ye Qisun extended an invitation to him, he readily accepted. In the late autumn of 1928, Wu Youxun walked into Tsinghua University. In order to show his respect to Mr. Wu Youxun, when researching his salary, Ye Qisun made a jaw-dropping decision: Wu Youxun's monthly salary is the highest in the Department of Physics, higher than that of the head of his department! From the letters and diaries of Wu Mi, Chen Yinke, Pu Jiangqing and others, we can know some details of the life of the professors in Tsinghua University, and a general overview of their daily life.Even ancient celebrities still have to care about daily necessities.The amount of salary is determined firstly to reflect the value of the scholar himself, secondly to reflect his status in this professional circle, and thirdly to reflect the importance the school attaches to the recruiter.In short, the additional meaning attached to the salary itself has always been valued by scholars. In "Wu Mi's Diary", there is an example of Zhang Pengchun's unfair salary setting that aroused the disgust of the professor.However, it was a rare thing in Tsinghua University at that time to set the monthly salary of subordinates higher than that of oneself.

Many years later, in the Tsinghua University, when it comes to examples of seeking talents and respecting corporals, people often cite Ye Qisun's actions the most. When Wu Youxun came to Tsinghua University, especially after returning to his scientific research position, he once commented on the laboratory led by Mr. Ye Qisun as follows—— At the beginning of 1929, at the 15th anniversary meeting of the Tsinghua Science Society, Wu Youxun said at the meeting: "China now has a physics laboratory that can tell the story of Central University, the former Peking University, and Tsinghua University, but among these three schools, Tsinghua University is the first. First, this list is not a fanfare, but a fact. Mr. Gaiye has never been good at publicizing, but he is realistic. In the future, we hope to have a few great physicists in our school, and at the same time hope to produce countless other great scientists.” ("Mr. Ye Qisun Chronicle ", "Journal of Tsinghua University" Philosophy and Social Sciences Edition, Issue 3, 1998, p. 36)

It was in Ye Qisun's laboratory that Wu Youxun, who had been away for two years, once again showed his fighting spirit. He achieved success again and again in a short period of time, and once again attracted the attention of the world's physics community.Yan Jici, a well-known scientist who was doing research at the Peking Research Institute, published an article in the first volume of the 32nd volume of the "Oriental Magazine", saying: "The earliest and most accomplished researcher in China should push Wu Youxun. He was born in the 19th year of the Republic of China. (that is, in 1930) once sent a research paper on X-ray scattering to the British "Natural Weekly" for publication. The physics research we Chinese did in China was sent to a foreign magazine for publication. This is the first time to break the topic. It is indeed a memorable event!" He made a statistic. In the four years from 1930 to 1933, there were 16 important papers in China, 9 papers from the Department of Physics of Tsinghua University, 2 papers from the Department of Chemistry of Tsinghua University, and the rest were from Yenching University. Written by the Department of Physics.And Wu Youxun wrote 8 articles by himself.

Today, the laboratory of the Department of Physics of Tsinghua University has long disappeared.If someone comes to Tsinghua with the mood of exploring the ancient world, the only thing similar to it can be found is the ultrasound laboratory founded by Mr. Zhu Guozhen. In 1952, the Department of Physics of Tsinghua University founded by Mr. Ye Qisun was abolished, and the laboratory dissipated like a cloud of smoke.Mr. Zhu Guozhen is the last graduate of the Physics Department of Tsinghua University, and he is the last passenger of the last train.The reason why it was named "last" was because he stayed in school as a teaching assistant, and he was the last one to get off this bus.After the adjustment of departments, even Mr. Ye Qisun left Tsinghua University, while Zhu Guozhen stayed.In a sense, he is a remnant of the Physics Department of Tsinghua University.

Zhu Guozhen is like the last successor of Ye's workshop.Although he is much different from Ye Qisun in terms of age, he is very similar to Ye Shi in terms of mental temperament and thinking style.Relying on the hands-on ability he learned in the Department of Physics, he made research equipment by himself, and even created an ultrasonic laboratory.In this small world that looks like a family workshop on the surface, each instrument looks rustic, but it is full of spirituality.In the eyes of Tsinghua people who have transformed into an engineering university, there are too many legends gathered in this dilapidated one-story house. Any humble instrument may be a solid support for a cutting-edge scientific research project.It was in this world that Zhu Guozhen discovered a new mechanical wave - the director wave in liquid crystals, which attracted the attention of the international academic community.Many foreign experts tried to find the waves that only existed in the liquid crystal theory with advanced instruments and equipment, but they all failed one by one.Luck doesn't seem to favor the owners of these luxurious devices. Zhu Guozhen's thesis was published in the fourth issue of "Journal of Tsinghua University" in 1981, and was later published by foreign authoritative academic journals.Many famous foreign scholars and experts, including Lin Jiaqiao, an old alumnus of Tsinghua University, also visited Zhu Guozhen's ultrasound laboratory.Mr. Lin Jiaqiao has now settled in the United States and is already a world-renowned physicist. When he was wandering in the self-created laboratory of Zhentufa Shangma in Zhuguo, the Yeshi workshop he was familiar with a few years ago returned to his eyes. .Just like a farmer lingers on the land he has cultivated and cared for all his life, the smell, color, and shape of this land are all imprinted with distinct personal marks. Even if you close your eyes, you can judge it from the breath. life code.Lin Jiaqiao excitedly told the people accompanying him that this is the tradition of the old physics department of Tsinghua University and the style of Ye Qisun's laboratory! Some foreign experts said: "We just want to visit such a laboratory. Here we can see creativity. This kind of equipment for discovering new physical phenomena cannot be seen or bought anywhere in the world. We should pay attention to such a laboratory." Salute to the laboratory. Tsinghua University has many large scientific research laboratories, which are very beautiful, and the equipment and instruments are very expensive, but these things are bought and imported. There are plenty in our university, so there is no need to visit here..." In the laboratory founded by Ye Qisun, Wu Youxun stayed for 17 years.When recalling Master Wu, Wang Ganchang said: He paid special attention to physical experiments in teaching. He introduced and analyzed important experiments and conclusions of modern physics, such as Millikan's oil drop experiment, Thomson's parabolic ion spectrum, Townsend's gas discharge research, Luther Fu's particle scattering experiment and so on.He paid special attention to training students' ability to engage in experimental physics research, so that students can fully master experimental skills, strive to improve the accuracy of experiments, and base their understanding of physical theory on solid experimental facts.Professor Wu Youxun also taught me to do the experiment. It was the winter of 1929. After I graduated, I stayed at the school as a teaching assistant. He determined a research subject for me: "The intensity of radon gas around Tsinghua University and its daily changes."In order to complete this project, Professor Wu and I went to the library to find reference books, went to school and even went to the market to choose equipment and equipment, and taught me how to do experiments.So starting from November 1929, I put a 6-meter-long bare copper wire with a diameter of 0.5 mm horizontally in the air at a height of 5 meters outside the laboratory before 9:00 a.m. every day.Insulate it with a wax rod, and use an electrostatic machine to make the wire have a negative potential of 3000 volts. Since the electrostatic machine generally gives a higher potential, it is kept at the required potential by the variable resistance leakage method.Bare copper wire stands in the air until 11am, then it is carefully wound around a wire frame.After the electrostatic machine stopped working for 2 minutes, put the wire frame into the insulating box of the gold leaf electroscope, read the discharge rate of the gold leaf through the microscope, and record the atmospheric pressure, wind speed and direction, and the nature and nature of the cloud on that morning. distribution, temperature. If this experiment was done in summer, there would be no difficulty. At most, you would sweat a little, and just pour it on rainy days; but this is winter, and the whole experiment was done in winter. The winter in Beijing at that time was colder than it is now. , I have to repeat the work of setting up wires, winding wires, and observing the weather every day outdoors in a world of ice and snow, and it is even worse when encountering bad weather.I remember that there was a strong wind once, and the bare copper wire was blown down by the strong wind as soon as it was put on the rack, but the experiment still needs to be done!I re-framed again, and fought against the strong wind for three times before I was considered a firm frame. I was exhausted, my hands were frozen, and it hurt like needles when I went back indoors. In this way, I continued to do it for 6 months, collected complete data and monthly changes in the average and maximum values ​​of atmospheric radioactivity, drew conclusions, and wrote a paper.After several years, when I became a professor myself, I deeply understood the original purpose of Professor Wu Youxun asking me to do this topic. In addition to thoroughly studying the influence of meteorological factors near Beiping on atmospheric radioactivity, the more important thing is to exercise and cultivate His students have the ability and patience to do experiments by themselves, even under harsh and harsh conditions, the experiments cannot be interrupted. ("Century Tsinghua", Guangming Daily Press, 1998 edition, pp. 224-225) In Wang Ganchang's narration, we have a vivid and intuitive perception of the hands-on ability mentioned by these technological sages.Scientific research is not just sitting in front of the instrument and staring intently, it is not only the slender clouds in the greenhouse doing tricks, but sometimes it is also exhausting the muscles and bones and starving the skin.It is said that in the process of searching for radium, the Curie couple repeatedly chemically separated and physically measured several tons of spent uranium slag provided by the Austrian government. After three years, their actions can be compared to a foolish old man moving mountains.When Mr. Ye Qisun tested the listening situation in the auditorium of Tsinghua University, he usually conducted it in the dead of night. In order not to affect the work of the next day, he often led the teachers to work overtime on Saturday night.Don’t think that this is a coincidence. It is the first research on architectural acoustics in China. Everyone participated in it, and it took two years to do it.Ye Qisun wrote in the paper "Hearing Difficulty in the Auditorium of Tsinghua University and Its Correction": "It has been two years since the problem started. The investigation by the United States takes time, and there is no time to sort out the materials after they arrive, so they have been put on hold for a long time. The experiment must be done after the lights are turned off, at most once a week, mostly in the middle of the Saturday night, so as to wake up the next morning; however, it cannot be done when there is wind; because of the nature of this problem, it really takes a long time.” And Wu Youxun spends the most time in the laboratory in the Department of Physics. He works silently in the physics world all day long, just like a farmer tending crops, using his hard work and sweat to get a bountiful harvest season after season.In Tsinghua University, Wu Youxun is the one who has the taste of Chinese farmers in the field of scientific research, and Wu Youxun is the one who has the most rustic temperament of farmers. The story of Corporal Ye Qi and Sun Lixian continues. In 1934, Ye Qisun handed over the position of head of the Department of Physics to Wu Youxun. In 1937, Ye Qisun again handed over the position of dean of the Faculty of Science to Wu Youxun.