Lin Jiaqiao (19 16~20 13) is an applied mathematician, physicist and astronomer. Born in Beijing, China. 1937 graduated from Tsinghua University. He has taught in Tsinghua University, China, California Institute of Technology and Brown University. He has made outstanding contributions to the development of modern applied mathematics and fluid mechanics.
1965438+On July 7, 2006, Lin Jiaqiao was born in Beijing, originally from Fuzhou, Fujian. His father, Lin Kai, was a civil servant of the Ministry of Railways in the late Qing Dynasty, and his uncle, Xu Lin, was one of the six gentlemen of the 1898 Movement. My father died young and was raised by my mother Deng, the sister of a famous educator. Lin Jiaqiao was very clever at an early age and became famous at an early age. 1933 was admitted to the physics department of the national Tsinghua University with the first place in the whole school, and 1937 graduated with the first place.
The faint heart of Tsinghua students serving their country.
At that time, Tsinghua was at the helm of Mei Yiqi, and a large number of famous scholars returned from studying abroad gathered. The Department of Physics in Lin Jiaqiao includes famous physicists Ye, Wu and Zhou Peiyuan in modern times.
From 65438 to 0933, Lin Jiaqiao, who first entered the Tsinghua campus, felt that the campus was like a "paradise". "Beautiful campuses, grasslands, buildings and equipment are full of international flavor; It was very different from the old house in Beijing at that time. " On the occasion of the 70th anniversary of Tsinghua, Lin Jiaqiao wrote: "Many students drink coffee, black tea and ice cream on campus for the first time, and enjoy the soft corn steamed bread in the canteen of the Second Hospital. In addition, there are many things that middle schools have never seen, such as gymnasiums, swimming pools, shower rooms and libraries. Such an environment is very suitable for students to study and work with peace of mind. "
Lin Jiaqiao recalled that there was a small gap between universities and foreign universities at that time, and several professors in Tsinghua spoke very well. Young people who have just returned from abroad with a doctorate have brought very advanced knowledge and the students have worked hard. In her freshman year, Lin Jiaqiao took the general physics course of Professor Sabendong. Teacher Sa writes his own textbook, and once a week, he takes a quiz of 15 minutes.
Among many teachers, Zhou Peiyuan, who was later called the originator of applied mathematics in China, had the deepest influence on Lin Jiaqiao. At that time, Zhou Peiyuan gave up the general theory of relativity, which he had studied for many years, and devoted himself to the application of mathematics in aviation, making his own plane for China. He not only influenced Lin Jiaqiao in academic attitude, but also led Lin Jiaqiao to choose an aviation-related issue-turbulence. Lin Jiaqiao once said with emotion: "Although my final work direction in academia is not completely limited to what I learned in college;" However, this learning experience is very important for my future career development. "
After graduating from Tsinghua, Lin Jiaqiao dreamed of going to the United States to study top science and culture, so that China could step into the forest of modern countries as soon as possible. 1939, Lin Jiaqiao, Qian Weichang, Guo Yonghuai and other 2 1 students were admitted to study in Britain by boxer indemnity at the same time. Due to the outbreak of World War II and the interruption of shipping, the group was blocked when it returned to Kunming via Japan. Later, with the help of Mr. Zhou Peiyuan, it was not until 1940 that Lin Jiaqiao and others were transferred to the University of Toronto for further study. A year later, Lin Jiaqiao got a master's degree and was recommended by Zhou Peiyuan to study at California Institute of Technology. He studied for a doctorate under the guidance of Professor Theodore von Kármán, the father of missiles in the world, and came up with shining names such as Qian Xuesen and Guo Yonghuai under the guidance of Master von Carmen. Lin Jiaqiao studied the stability and turbulence of fluid dynamics under the guidance of this master.
Von Carmen not only gave Lin Jiaqiao general guidance, but also made him complete the doubtful part of Heisenberg's paper "On the Stability and Turbulence of Fluid Flow", a famous theoretical physicist and one of the founders of quantum mechanics. From 65438 to 0944, when Dr. Lin Jiaqiao graduated, he wrote three doctoral theses about Heisenberg, which were later published in the American Journal of Applied Mathematics.
Lin Jiaqiao, 29, became famous in academic circles because he solved the unsolved problems in Heisenberg. When he got his doctorate, Von Carmen invited Lin Jiaqiao to a restaurant in China and introduced him to Von Neumann, who later became the father of computers in the world. At that time, von Neumann was using a propulsion computer. Von Carmen brought the topic of Lin Jiaqiao to von Neumann, and the result was the same. Heisenberg later commented on Lin Jiaqiao as follows: A China man used abstruse mathematical methods to get better results.
After graduating from Ph.D., Lin Jiaqiao first went to Brown University and was poached by MIT a year and a half later. 1953, Lin Jiaqiao was appointed as a professor. 1966, he was promoted from professor to college professor. In MIT, where masters gather, no more than 100 people can be promoted from professors to university professors. From 65438 to 0962, Lin Jiaqiao became a member of the National Academy of Sciences. In the field of applied mathematics, Lin Jiaqiao developed analytical characteristic method and WKBJ method, and he is the leader of contemporary applied mathematics school. He applied mathematics to the research of aviation and astrophysics, which greatly promoted the progress of basic science in these two fields. In the United States, some people regard Lin Jiaqiao as "the father of applied mathematics", and some people say that "he made applied mathematics become a respected subject from a neglected subject".
Yuan Qi from the Astronomical Institute of China Academy of Sciences went to MIT to do postdoctoral research with Lin Jiaqiao. The first deep impression that Lin Jiaqiao left on Yuan Qi was not the depth of his mathematical research, but the thoroughness of his physical research. Yuan Qi remembers that Lin Jiaqiao never robbed others of their research results, and he even attributed the creation of density wave to Lindebu many times. In fact, the density wave proposed by Rindborg in 1959 is "very rough and primitive", which is different from the theory carefully constructed and deduced by Lin Jiaqiao. But when Professor Tumley of MIT refuted the density wave, Lin Jiaqiao immediately blocked the rebuttal with the concept of standing wave, and later established the concept of density wave with the framework of mathematical physics, and made it develop into a provable theory.
In Yuan Qi's memory, Lin Jiaqiao looks like a gentleman and a scholar. He is not tall and kind to people. He is a "Beijing film". His wife Liang Shouying is the sister of Liang, the father of the famous flying fish missile. The couple come from the same town. Liang Shouying has been teaching Chinese at Harvard University. He is not only Lin Jiaqiao's wife, but also treats students and younger generations like family. Yuan Qi (1966) has just arrived in Persia and suddenly has no friends. It was Mrs. Lin's concern that brought him warmth.
Adhere to scientific research and education.
Although Lin Jiaqiao has been engaged in scientific research in the United States for a long time, he has been paying close attention to the development of education and scientific research in China. From 65438 to 0972, after the thaw of Sino-US relations, Lin Jiaqiao made many academic visits to China, invited many famous American experts to give lectures in China, and accepted many China scholars to further their studies at MIT, thus training a group of scholars for China.
Lin Jiaqiao has many titles, such as an international authority on mechanics and applied mathematics, an astrophysicist, a member of the National Academy of Sciences, a member of the National Academy of Arts and Sciences, an honorary professor at MIT, and a professor at the Institute of Advanced Studies at Tsinghua University. His life has witnessed great changes in China. In the last 10 year of his life, he returned to his alma mater.
In 2002, at the age of 86, Lin Jiaqiao decided to return to Tsinghua University to settle down. At that time, his good friend, Chen Shengshen, the father of differential geometry, had set up a mathematical research institute in Nankai University. He said that because of Chen's lessons, he was willing to go back to his alma mater to help. In order to promote the research of applied mathematics in Tsinghua University, he presided over the establishment of Zhou Peiyuan Applied Mathematics Research Center of Tsinghua University, and devoted himself to the biological research with applied mathematics methods. He thinks this field is "full of opportunities". As he said when he met Tsinghua alumnus and Chinese-American historian He Bingdi at 1965, "it is important to never be a second-class topic in any line of work."
Lin Jiaqiao's ideal is to hope that Tsinghua Institute of Science can restore its former glory. According to Yong Wen 'an, director of Zhou Peiyuan Applied Mathematics Center, Lin Jiaqiao will go to work in the Mathematics Center every Monday and Thursday morning after returning to China. Since 2005, although he had to travel in a wheelchair, he still insisted on attending the weekly discussion class in the center. He donated all the living expenses issued by the state. In 2007, he sold all his stocks in the United States and donated all 4 million yuan to the Mathematics Center.
In view of the present situation of education and scientific research in domestic universities, he emphasized that the concepts and differences between applied mathematics and pure mathematics in China are rather vague, and universities simply equate "applied mathematics" with "practical mathematics", emphasizing science and technology over science. The core of applied mathematics is to solve the problems of entity science by mathematical methods. In China, it should be an independent subject which is quite different from pure mathematics.
Lin Jiaqiao demands too much of his ideal doctoral student: he must undertake a systematic and complete job, have a comprehensive understanding of his own field, be proficient in writing papers in English, and be able to discuss with international colleagues without obstacles.
Lin Jiaqiao made a profound reflection on the history and present situation of higher education in China. The low achievement of higher education in the 60 years since the founding of New China may be related to the adjustment of colleges and universities at the beginning of the founding of New China. At that time, China studied the Soviet Union and concentrated all talents to solve practical problems, not necessarily academic problems. So he may gradually get away from the main responsibilities of the university. The main duty of a university should be to cultivate new talents and promote new academic development. Universities should adhere to the principle of academic first, and don't pretend to be masters.
When faced with the question of when the academic circles in China won the Nobel Prize, Lin Jiaqiao thought that the development level of China University might be a little worse now. "I think it is not easy for people from a university in China to do research in universities in China and win the Nobel Prize." It is imperative that China needs a group of first-class universities to do research. It is impossible to rely on only one or two universities, and the overall level of universities needs to be improved. "At present, the number of better universities in China, such as Tsinghua, Peking University, China University of Science and Technology and Fudan University, should be increased to around 10, so as to form a good scientific research environment."
In inter-school communication, we should make clear the difference between "what we want to know" and "what we want to do". Key technologies may be difficult to obtain, but the basic knowledge is open and can be deepened without huge capital and manpower investment. What is "more important" and can bring long-term effects is precisely the exchange and study of basic science. Of course, you must first "practice your internal strength" and reach the level of equal dialogue with international counterparts, so that exchanges and cooperation can proceed smoothly.
"When communicating with famous foreign universities, the most important thing is to understand each other's strengths and weaknesses and learn from each other's strengths. "It is a short-sighted and one-sided view to pay too much attention to practicality and think that' walking at the cutting edge and cutting edge' means introducing advanced technology. In principle, advanced science should pay equal attention to advanced technology, but the proportion distribution is a difficult problem to decide. Because this decision should be based on the needs of the country and the actual situation of human, material and financial resources, and this situation also changes with the times.
MIT's "compulsory course for the whole school" is a reference system. At MIT, all students must learn four basic sciences of mathematics and science students in the first year. "China's education began to highlight professionalism very early, and MIT's compulsory course is first wide and then deep." Lin Jiaqiao believes that it may not be necessary to completely copy this model, but it is worth learning to invite scholars outside the school to objectively examine the teaching and research work in related fields.
MIT, once famous for its engineering achievements, has made rapid progress in the field of science, and the development level of biology and other disciplines is even more impressive. Therefore, communication with MIT should attach importance to science and engineering, especially science.
Pursue the research career that I love all my life.
In his later years, Lin Jiaqiao lived in seclusion and hardly gave interviews to reporters. Teachers and students in the center of applied mathematics can often see him. Before he was bedridden, he insisted on attending the weekly discussion class in the center, rain or shine. People often see his wheelchair appear in the corridor on time. He will take part in the discussion after listening to other people's lectures, which usually lasts for two or three hours.
At the age of 94, when Lin Jiaqiao gave lectures to students in Tsinghua University, he suggested that scientific research should always "follow the fashion" and pay attention to those hot and cutting-edge issues. He wrote an inscription to the students: "The study of natural science is endless, which can be regarded as a lifelong goal and a lifelong career."