Pan Junhua (1930.10.14—2023.12.18), a native of Changzhou, Jiangsu, is an outstanding expert in applied optics in mainland China. In 1952, he received a bachelor's degree in mechanical engineering from Tsinghua University, and after graduation, he worked at the Changchun Instrument Museum of the Chinese Academy of Sciences (now the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences). In September 1956, he went to the Soviet Union for further study, and returned to China in July 1960 after receiving a doctorate. In 1980, he went to work in Nanjing Astronomical Instrument Factory of Chinese Academy of Sciences (now Nanjing Astronomical Instrument Co., Ltd., Chinese Academy of Sciences). In 1999, he was elected as an academician of the Chinese Academy of Engineering. In 2000, he was hired as a researcher at the Institute of Modern Optical Technology of Soochow University. He has won many awards such as the National Science Conference Award, the first prize of the National Science and Technology Progress Award, and the third prize of the National Science and Technology Progress Award.
Many years ago, when a child looked up at the stars and made a wish, he probably never imagined that one day in the future, an asteroid named after him would twinkle in the night sky. In 2019, the asteroid with the international number 216331 was approved by the International Minor Planet Center and the International Committee on Minor Planet Nomenclature, and was officially named after a Chinese scientist. This scientist is Pan Junhua, a well-known expert in applied optics in mainland China and an academician of the Chinese Academy of Engineering.
The voice of the deathbed, the purest patriotism should be expressed with actions
"I'm afraid that if I don't say it, I won't have a chance......" In the early morning of November 2023, Pan Junhua dialed the phone of the Secretary of the Party Committee of the School of Optoelectronic Science and Engineering of Soochow University: "I want to express two meanings: one is to thank Soochow University for its care and care for me over the years, and the other is to thank the country and the party for cultivating me, so that I can do something for our country......"
In the last few years of Pan Junhua's life, he was still deeply concerned about the scientific research work of teachers and students. When he was healthy, he walked from his home to work at Soochow University, where he taught, rain or shine. Teachers and graduate students from the School of Optoelectronic Science and Engineering at Soochow University are "regulars" in his office. For the problems encountered in the process of experiments, Pan Junhua always tirelessly pointed out the research direction for them. He often said to his students: "In the field of applied optics, optical design, inspection, and processing are inseparable, and if the three are well communicated, many technical problems will be easy to solve." Regardless of the area of research you focus on, it's important to be aware of all three. Influenced by him, the teachers of the School of Optoelectronic Science and Engineering of Soochow University train graduate students, and they all advocate to be an optical researcher with engineering concepts, from design to preparation process and testing, must participate in and complete the whole process.
A month after that phone call, 93-year-old Pan Junhua passed away in Suzhou, turning into a star and looking at the earth from afar. "The last time I met Mr. Pan was to discuss with him the large-aperture optical mirror with a 630 mm aperture." Wang Wei, a student of Pan Junhua and a teacher at the School of Optoelectronic Science and Engineering at Soochow University, recalled what impressed him the most: "At first, I didn't want to trouble him, but Mr. Pan found out about this problem and took the initiative to find us. He is very rigorous in his work and records every detail. ”
In his later years, he still insisted on communicating with teachers and students in the form of letters, encouraging everyone to "youth is precious, don't waste it". In a report, Pan Junhua shared his life motto with teachers and students: "Don't compare money to enjoyment", "Don't be complacent at any time", "The most important thing is to remember that you are Chinese...... The seemingly simple and unpretentious words are full of the most sincere patriotic feelings of this older generation of scientists. And he also practiced the words "serving the country with science and technology" all his life.
The origin of scientific research, the dream of the starry sky when I was a child will take a lifetime to complete
Pan Junhua's fate with the "starry sky" has been formed since he was a child, and in the summer when he was a child, his favorite thing to do was to lie on the wooden board and enjoy the shade, gazing at the starry sky, full of curiosity and longing.
However, Pan Junhua's path to study was full of ups and downs due to the war. After entering Tsinghua University in 1949, his thirst for knowledge grew day by day, and he felt that everything was new and he wanted to learn everything. With his strong interest and hobby, he joined the Astronomy Study Club to systematically study astronomy knowledge and a series of book report activities with everyone. "Parade of the Stars", "Spherical Astronomy", "Solar System", ...... Pan Junhua is tireless in the ocean of astronomical knowledge, and as long as he receives the notice of the astronomical study meeting, he actively participates. In his notes, the star maps drawn by himself made him get closer and closer to his dream.
In addition to listening to the report, Pan Junhua also taught himself a lot of astronomical knowledge by extracting planetary dynamics, studying ancient Chinese astronomical contributions, observing celestial phenomena and other methods, and even took his father's reading glasses and his second brother's myopia glasses from home, and cobbled together a low-powered Galilean telescope to facilitate his own observation of the stars.
In 1956, with a good foundation in Russian, Pan Junhua was sent by the Changchun Instrument Museum of the Chinese Academy of Sciences to the Leningrad Pulkovo Observatory in the Soviet Union to study astronomical optics with Professor Maksutov. "During those days abroad, the whole person was like a sponge, absorbing knowledge nutrients as much as possible, looking forward to serving the country after returning to China after completing his studies." This belief sustained him through 4 years of lonely life in a foreign land. It was the accumulation of studying in the Soviet Union that allowed Pan Junhua to transform from an astronomy enthusiast to a researcher of modern astronomical optics. During this period, he proposed a new inspection method for the secondary convex secondary mirror of large telescopes, which was called the "Pan's method" by the Soviet side, and was widely used.
In his free time, Pan Junhua's favorite thing to do is "ground glass". He once wrote to an optical company in Shanghai to inquire about the cost of grinding a 50 mm aperture plano-convex lens, and Pan Junhua's monthly food cost was 8 yuan, and when he learned that the cost was 50 yuan, he had to try to polish it himself. In addition to working in the Changchun Instrument Museum, Pan Junhua did not hesitate to spend most of his salary on the purchase of materials, and his colleague Gan Fuxi once said: "Grinding glass, feel good, this is Pan Junhua's lifelong hobby." During his study abroad, Pan Junhua still loves glass grinding, and his mentor Maksutov also commented that his polished parabolic mirror is "very good". It was the experience of many years of self-polishing that laid a solid foundation for Pan Junhua's subsequent astronomical and optical research.
Once, Maksutov told his students about a formula he had recently deduced, and Pan Junhua also deduced it with the mindset of learning, only to find a small error and correct the formula. It just so happened that when the tutor himself used this formula, he found that he could not always do it at one time, so he used his modified formula to derive it, and found that the problem was solved very smoothly. "It makes me feel happy and satisfied to bring a graduate student like Pan Junhua." Pan Junhua was deeply moved and encouraged by his supervisor's praise, and strengthened his determination to choose the path of astronomical optics scientific research.
The original intention of serving the country must be practiced with hard work
After returning to China in July 1960, Pan Junhua was determined to put what he had learned into work and serve the country. Pan Junhua began to participate in major national defense projects such as 60# missions and 150# missions, and with the accumulation of knowledge when studying abroad and the solid practical foundation laid by many years of glass grinding, he led the team to design a mirror grinding machine and a knife edge tester, helping the mainland to establish a new optical inspection method. Liu Lu of the Institute of Optics and Mechanics once commented: "Without Pan Junhua coming back from the Soviet Union, the 150 theodolite would not have been made." ”
In the seventies and eighties of the last century, when the country was focusing on tackling the 2.16-meter astronomical telescope, Pan Junhua was appointed as the leader of the technical group. During the development of the project, there were many problems, ranging from the site and implementation of the installation and commissioning of the telescope, to the damage caused by the abnormal rotation of the motor during the focusing test of the secondary mirror, and the work was very difficult. At that time, Pan Junhua, who was nearly 60 years old, still insisted on climbing up and down the ladder 30 meters every day to debug the instrument and solve the problem. Due to various factors, he had to use a slightly flawed Soviet mirror blank during the project, due to the uneven hardness of the mirror blank everywhere, and the non-axisymmetric local height during polishing, so that the workers felt that they could not grind any longer, and the project was facing a halt. Pan Junhua carefully checked and found the problem, and suggested stopping the machine to grind by hand, and after many efforts, it took 3 years to successfully "grind down" this piece of mirror blank. From the second start of development to the trial observation in 1989, the development of the 2.16-meter astronomical telescope took a full 15 years.
In Pan Junhua's view, as long as it is needed by the country, it should be done responsibly, and solve problems when encountered, without asking for returns, regardless of personal gains and losses. This astronomical telescope, which was the largest in China and even Asia at that time, won the first prize of the Science and Technology Progress Award of the Chinese Academy of Sciences in 1997 and the first prize of the National Science and Technology Progress Award in 1998. However, what makes Pan Junhua most proud and gratified is that this telescope is still full of observation tasks, "it is aimed at the vast starry sky every day".
From "grinding glass" to manufacturing "the great vessel of the country", Pan Junhua has walked for many years, and the hardships and sweat are difficult to summarize in simple words. He often said: "Pushing formulas is not the whole of scientific research, you must try it." He is a profound optical expert, from optical design to processing and inspection, Pan Junhua's advantage is that he can be competent in the whole process. Wang Daheng once used "the most engineering concept of optical experts" to evaluate Pan Junhua, "engaged in applied optics, optical engineering, to have engineering concepts. The so-called engineering concept is that he designed something not only to consider how to design it, but also to consider what could be made and realized according to the level of processing and manufacturing at that time."
Later, Pan Junhua successively took over many major national defense research tasks such as the National 541 Mission, the 216 Project, the Resource 1 Satellite, and the 921 Camera Project. Under his leadership, the team of Soochow University has also completed the development of the main optical system of the China-Pakistan Cooperation Resources No. 3 meteorological satellite, the optical part of the prototype of the soft X-ray telescope for solar observation, and other projects.
As a model, Yuhe's mission will burn to the last moment
In 2019, on the occasion of the naming of "Pan Junhua Star", the "SU University Reading Festival" specially invited Pan Junhua to share his growth and success experience. With the title of "My Life", he fondly recalled his study and career during the war, and summed up his life with the words "bow your head to pull the car and look up at the road", encouraging the students of Guangzhou University to be down-to-earth and look up at the starry sky. Faced with the question of "what does the naming of the asteroid mean", he indifferently said "it doesn't matter", showing his indifferent character of fame and fortune.
Pan Junhua has been chasing light all his life, and it is like a beam of light illuminating the latecomers who are moving forward in the field of optics. Yang Xiaofei, a teacher from Soochow University, encountered the problem of moiré fringes when processing off-axis paraboloids, and the laser interferometer could not measure them. He asked Pan Junhua for help, and Pan Junhua pointed out that it was the stray light interference caused by fine beam imaging, and suggested spatial filtering to solve the problem. The title page of the "Chasing Light Notebook" issued to the new students every year by the School of Optoelectronic Science and Engineering of Soochow University is printed with Pan Junhua's words: "All my life, I have been seeking knowledge and chasing light, doing every job conscientiously, doing every job from beginning to end, and hoping to do a good job in the career I love." It is my honor to contribute a little bit to the development of my motherland. Once, when asked about the reason for his patriotism, he responded in nine words in a concise and deep nine words: "Patriotism does not need a reason." This is not only his heartfelt voice, but also the pure and touching emotional outpouring of a scientific and technological pioneer and Communist Party member. Until his deathbed, he modestly downplayed his important contributions as "doing just a little thing."
Although Pan Junhua has left us, this "chasing light" academician is like a beacon in the field of optics, continuing to guide those who come after him to look up to the stars, be down-to-earth, and write new glories.