A red-header document from 1988, in which a division member (academician) politely declined an appointment as an expert of a discipline review panel, was turned into an image and posted online earlier this year. It quickly reached over 100,000 reads. Netizens lamented that the protagonist of the story, Hong Chaosheng, "was a true scholar." Who is Hong Chaosheng? Many people have never heard the name.
"If he were still alive, he certainly would not want to become the focus of public attention," said Li Laifeng, a researcher at the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Physics and Chemistry) and a student of Hong Chaosheng.
In 1983, when Hong Chaosheng was 63 years old, he wrote a letter to Science News (the predecessor of China Science Daily), hoping the media would not publicize him. He said, "That would make me extremely uncomfortable."
In 2024, six years after Hong Chaosheng's death, the Institute of Physics and Chemistry erected a statue of him to promote the spirit of scientists. Li Laifeng said, "This certainly also goes against Mr. Hong's wishes, but considering its educational significance for young people, the statue was still erected."
Every year on Qingming Festival, Teachers' Day, graduation season, or October 10, Hong Chaosheng's birthday, young teachers and students spontaneously visit the statue, placing self-purchased flowers and the gentleman's favorite chocolate to commemorate this pioneer of China's low-temperature field.
Hong Chaosheng wanted to erase his contributions his entire life, yet his name became a signpost instead. Everyone who was guided by him onto the path of scientific research is grateful to this "old gentleman."
On the morning of Teachers' Day this year, September 10, someone placed a bouquet of flowers in front of Hong Chaosheng's statue. Photo by Li Laifeng.
The "Old Gentleman" Who Was Always Refusing
In that viral image with over 100,000 reads, there is a yellowed document. At the time, the National Natural Science Foundation of China was preparing to form its second discipline review panel and planned to appoint Hong Chaosheng as a member of the physics discipline review group of the Department of Mathematical and Physical Sciences. In the lower left corner of the document, Hong Chaosheng's blue handwriting remains: "I am afraid that in the near future my working time and energy cannot yet be devoted to this work. Because I know this work is very important, it is not an easy matter for me either. I am very sorry."
Li Laifeng also saw this popular image online. He said, "For Mr. Hong, this was an extremely ordinary matter."
There were many things the "old gentleman" refused in his life that were even more "explosive," most of them related to "titles." Academician Zhao Zhongxian, the main founder of China's high-temperature superconductivity research, once encountered such a situation.
It was around 1982. Zhao Zhongxian walked into Hong Chaosheng's office holding two pages of manuscript paper covered with writing. The manuscript was an entry on "Hong Chaosheng" written by Zhao Zhongxian for the Chinese Encyclopedia (Physics Volume). The book was overseen by Qian Sanqiang and included only people who had made important contributions to the development of human physics. Very few people of Hong Chaosheng's age group were included. At the time, Qian Sanqiang and Qian Linzhao entrusted Zhao Zhongxian with writing Hong Chaosheng's entry. Following the style of foreign encyclopedias, Zhao Zhongxian quickly wrote a first draft, then thought, "Such an important matter, I should first show it to Mr. Hong before submitting it to Mr. Qian." Unexpectedly, as soon as Zhao Zhongxian explained his purpose, he met with Hong Chaosheng's opposition.
Zhao Zhongxian, who had worked in Hong Chaosheng's research group for many years, knew Hong Chaosheng's style well. "Whether to write about you or not is not for you or me to decide. The two Mr. Qians asked me to write it. If I don't write it, they will find someone else." Hearing this, Hong Chaosheng had no choice but to take the manuscript and read it. After reading, he put down the paper and said, "You're writing my eulogy here." Zhao Zhongxian laughed and said, "You know what, writing a eulogy really does require consulting this. You should still revise it carefully." Helpless, Hong Chaosheng had to pick up his pen and make changes. He deleted the title "Vice Chairman of the Chinese Physical Society" and also deleted the word "Standing" from "Standing Committee Member of the Department of Mathematical and Physical Sciences of the Chinese Academy of Sciences," changing it to "Committee Member." However, the publisher did not accept his suggestions. The published entry not only included "Vice Chairman of the Chinese Physical Society" but also "Committee Member and Standing Committee Member of the Department of Mathematical and Physical Sciences of the Chinese Academy of Sciences."
Hong Chaosheng always refused various "titles" and rarely spoke proactively about his own contributions. Even Li Laifeng, who was very close to Hong Chaosheng, seldom heard his teacher say things like "back in those days." Hong Chaosheng and his wife Li Ying had no children their entire lives and were close to Li Laifeng. Hong Chaosheng and Li Laifeng were more than 40 years apart in age and got along like father and son, calling each other "Old Hong" and "Little Li." Only in Hong Chaosheng's later years did Li Laifeng piece together a complete "Old Hong" from public documents and yellowed notebooks. For example, from the article "Please Let History Remember Them" published by former State Councilor and former Vice President of the Chinese Academy of Sciences Zhang Jinfu, he learned that "Old Hong" had contributed to the "Two Bombs, One Satellite" cause, and his photo was even included in the article. From "Old Hong's" notes, he learned that "Old Hong" had discussed face-to-face with Premier Zhou Enlai on July 14, 1972, about how to strengthen domestic basic research.
"Several of his personal honors, including two international awards, were obtained without his knowledge," Li Laifeng said with emotion. "He was someone who particularly loved to reflect on himself, always feeling that what he did was 'nothing much.'"
Hong Chaosheng working in his office. Photo provided by the Institute of Physics and Chemistry.
Was It Really "Nothing Much"?
Hong Chaosheng always described his work in an understated way. His assessment of his overseas study experience is a typical example.
In 1944, Hong Chaosheng was simultaneously admitted as a government-funded student to study in the United States and the United Kingdom, which was very enviable. In 1948, at the Massachusetts Institute of Technology in the United States, he earned his Doctor of Science degree in just two years and nine months. His advisor Nottingham was very satisfied with his dissertation and recommended him to give an invited report at the annual meeting of the American Physical Society, which was published in the American Journal of Applied Physics in January 1950.
Hong Chaosheng in the MIT laboratory in 1948. Photo provided by the Institute of Physics and Chemistry.
But when Hong Chaosheng recalled it, he said, "I had not yet completed the requirements of doctoral training. The dissertation was not my independent research achievement, and the leading ideas in it were not mine."
His assessment of his discovery of the "Hong Chaosheng Effect" was also extremely restrained.
In October 1948, Hong Chaosheng graduated from MIT and entered the Physics Department of Purdue University in the United States, participating in a semiconductor low-temperature electrical properties research project. The research group was led by internationally renowned semiconductor physicist Horowitz. He spent more than half a year building low-temperature experimental equipment with colleagues. After that, they began measuring the Hall coefficient and resistivity of germanium single crystal samples of different purities, trying to answer "whether, when impurity content is low, carrier transport properties would conform to the simple picture of semiconductors at that time."
The "simple picture" was a basic theoretical expectation in the semiconductor physics community regarding the electrical behavior of doped semiconductors: when temperature decreases, carriers provided by impurities would be "frozen" back to impurity energy levels, the material would tend toward insulation, and resistivity should rise sharply.
In the spring of 1950, just before leaving the United States, Hong Chaosheng observed an anomalous Hall effect: at low temperatures, the Hall coefficient showed a maximum, and resistivity no longer rose but tended to saturate. More critically, the higher the impurity concentration in the germanium sample, the higher the temperature at which the anomalous phenomenon appeared, and the lower the Hall maximum and low-temperature resistivity. Colleagues in the research group could not explain this phenomenon and found it "mysterious."
Before long, Hong Chaosheng figured it out and proposed that at sufficiently low temperatures, adjacent impurity atoms form an "impurity band." Electrons are no longer frozen on isolated impurities but can "flow" along the impurity band, forming a new conductive channel. This was the "Hong Chaosheng Effect" that later influenced the entire semiconductor physics community. It broke the expectations of the simple semiconductor picture and opened the frontier of research on electron transport in disordered systems.
This discovery is still written in the official introduction of Purdue University's Physics Department: "Hong Chaosheng first observed and explained impurity band conduction at very low temperatures... It triggered many theoretical studies of semiconductors, as well as later theoretical analyses of electrical transport in disordered materials. Mott, Anderson, and Van Vleck won the 1977 Nobel Prize in Physics because of this."
In 1981, Anderson was invited to give a lecture at Fudan University. In his lecture, he introduced that the first experiment his localization theory needed to explain was "Hong's experiment." Academician Ouyang Zhongcan of the Institute of Theoretical Physics of the Chinese Academy of Sciences once evaluated the "Hong Chaosheng Effect" as "'Nobel Prize-level' important work" and also mentioned that "many masters of contemporary condensed matter physics have cited this paper."
However, no matter how recognized this work was, in Hong Chaosheng's words, it was merely "a period worth remembering, which filled in preliminary training for independent research." He still felt that he was "shallow in physics knowledge and urgently needed strengthening."
Some people said that if Hong Chaosheng had not left Purdue University, he would very likely have participated in follow-up research and won a Nobel Prize. Hearing this, Hong Chaosheng shook his head and said, "There is no 'if.'"
In 1950, when Hong Chaosheng was about to leave Purdue University, Horowitz offered him a very high annual salary, hoping he would stay. But Hong Chaosheng still left, going to Leiden University in the Netherlands to do what he considered more important.
Leiden University is a world-renowned center for low-temperature physics research. During his time at Purdue University, he had written to his alma mater Tsinghua University asking what research direction would be appropriate after returning to China. Qian Sanqiang and Peng Huanwu jointly wrote back telling him that low-temperature physics was very important and that China should also carry out basic research in this area. They suggested he go to Western Europe for another year to broaden his knowledge of low-temperature physics.
During that year in Europe, he used his spare time to visit many laboratories. He saw the gap between China and the world in the field of low-temperature physics, saw that low-temperature technology would inevitably be linked to the development of national strategic high technologies in the future, and saw too many things that needed to be built from scratch.
History Will Not Forget
At the end of 1951, Hong Chaosheng returned to China. After that, he worked busily for the country for more than half a century.
When he wrote to the editorial department of Science News in 1983 refusing publicity, Hong Chaosheng said, "Now I only hope to be able to do a bit more practical work in a down-to-earth way." He evaluated himself this way: "I have worked at the institute for thirty years. The time has been long, and my position was one in which I could have done quite a lot. But what I accomplished was very little. Here, objective social factors are not the main reason. The key still lies in limitations of my own ability, subjective understanding, and way of thinking."
But in reality, after returning to China, Hong Chaosheng did many things that can be called "historical starting points." The first thing he did was go to the Institute of Applied Physics of the Chinese Academy of Sciences (renamed the Institute of Physics of the Chinese Academy of Sciences in 1958, hereinafter referred to as the Institute of Physics) and begin organizing a low-temperature physics laboratory. At that time, apart from Hong Chaosheng as the only senior researcher, there was only one junior researcher, one technician, and one apprentice. Small equipment and instruments such as liquefied air machines and compressors were all ordered from abroad through every possible means. Once, someone said to Hong Chaosheng, "Why don't you buy a helium liquefier? Didn't you also use a ready-made helium liquefier abroad?" "For this, I must rely on self-reliance and do it myself," Hong Chaosheng said. He judged that low-temperature technology would inevitably be linked to the development of national strategic high technologies and that it had to be built domestically. Facts confirmed his prediction.
In 1956, China's "Two Bombs, One Satellite" project was officially launched, creating a real and urgent demand for low-temperature refrigeration technology. It was precisely in that year that the first hydrogen liquefier, designed and processed by Hong Chaosheng's team themselves, was successfully debugged, producing 6 liters of liquid hydrogen per hour. By April 1959, they had successfully developed a helium liquefaction system pre-cooled by liquid hydrogen and produced China's first drop of liquid helium.
In 1982, some research groups of the low-temperature physics laboratory of the Institute of Physics became independent as the Cryogenic Technology Experimental Center of the Chinese Academy of Sciences, and in 1999 merged with the Institute of Photographic Chemistry of the Chinese Academy of Sciences to form a newly established institute—the Institute of Physics and Chemistry. Hong Chaosheng also joined the Institute of Physics and Chemistry along with the experimental center, participating in and witnessing the development of China's low-temperature technology. This experimental center became the Key Laboratory of Cryogenics of the Chinese Academy of Sciences in 2009 and became the National Key Laboratory of Cryogenic Science and Technology in 2024.
Today, China's independently controllable low-temperature refrigeration equipment is playing an irreplaceable role in areas such as aerospace cryogenic propellant support, strategic helium resource extraction, and major national science and technology infrastructure. The starting point of all this was the moment Hong Chaosheng resolved to "rely on self-reliance."
Of course, what he did went far beyond the low-temperature field. In 1953, together with Huang Kun, Wang Shouwu, and Tang Dingyuan, he carried out semiconductor science research and teaching, offering courses such as solid state physics and semiconductor physics at Peking University and the Institute of Physics, cultivating the first batch of talent for New China's semiconductor cause. In 1958, he established China's first superconductivity research group within the low-temperature laboratory, took the lead in proposing research on superconductors with superconducting transition temperatures above 80K, and organized research on superconducting films and computer components. The discipline of superconductivity was thus established in China.
These things all became starting points beneath the feet of later generations.
Ahead of His Time
When people marveled at Hong Chaosheng's vision and foresight, Li Laifeng nodded: "Mr. Hong could see clearly many things that others could not."
He was like a man walking ahead of time. Some things that looked very lively at the time were seen through and stopped by him; some topics that were initially not favored or not noticed became important research directions today under his strong support.
For a period, room-temperature magnetic refrigeration technology was particularly popular, and Li Laifeng very much wanted to work on it. This technology has no compressor and no refrigerants such as Freon. It was once considered promising for green household refrigerators, and many companies invested in research and development. Hong Chaosheng firmly opposed it: "Who, using a refrigerator at home, would still want to put a half-ton iron yoke block there? Even if the magnetic working material and technical route were successful, it could not enter ordinary households." Li Laifeng was unconvinced: "Others are doing it too. Others apply for projects. Why can't I do it? Do you think I don't have the ability?" Hong Chaosheng did not answer. He turned and went back to his office, took out several boxes of materials left from his own early research on room-temperature magnetic refrigeration technology, and placed them in front of Li Laifeng: "Whether others do it or not, I cannot control. You cannot do it. A person's scientific research life is limited. I don't want you to waste your time on a direction I have already seen through."
Time proved Hong Chaosheng right again. To this day, magnetic refrigeration household refrigerators remain at the 1997 prototype stage and find it difficult to enter industry. "Because of him, I saved a lot of time," Li Laifeng said.
Starting in 1999, before entering his office in the morning, Hong Chaosheng always first sat for a while in Li Laifeng's office. Each time, Hong Chaosheng put his bag on the sofa and sometimes sat for ten minutes, sometimes for an hour. During their "morning chats," the two talked about academia and their views on various matters. Li Laifeng would share his scientific research ideas, but "9 out of 10 ideas would be rejected."
"Among the directions that were killed was room-temperature magnetic refrigeration, while the one direction that was not killed was low-temperature materials, especially low-temperature steel," Li Laifeng said.
Li Laifeng earned his master's degree at the Institute of Metal Research of the Chinese Academy of Sciences and had accumulated experience in metal materials research. Hong Chaosheng strongly supported Li Laifeng in researching low-temperature steel and also suggested that he work with steel mills on research and development. Today, the "China High-Strength Low-Temperature Steel No. 1" developed by Li Laifeng's team has entered mass production and is used in China's first compact fusion energy experimental device (BEST).
Academician Zhou Yuan of the Chinese Academy of Sciences also anchored his direction with Hong Chaosheng's support. In 1961, Zhou Yuan was 23 years old and had just graduated from Tsinghua University. He was first assigned to the Institute of Semiconductors of the Chinese Academy of Sciences. Because semiconductor research cannot be separated from low-temperature technology, he was sent to the Institute of Physics for an internship under Hong Chaosheng. At that time, Hong Chaosheng was leading a team to develop a helium liquefier that did not require liquid hydrogen pre-cooling. Their original plan was to adopt the traditional international Collins-type scheme, but this scheme demanded extremely high machining precision: the gap between the piston and cylinder could not exceed 5 microns, and domestic mechanical processing levels simply could not reach that precision. The development work once stalled.
Inspired by the piston structures of internal combustion engines and Stirling refrigerators he had encountered in university, Zhou Yuan proposed a bold idea: lengthen the piston and move the seal from the low-temperature end to the room-temperature end, so that the gap between piston and cylinder could be relaxed from 5 microns to 100 microns. This plan differed significantly from common international practice, and almost everyone opposed it. Hong Chaosheng did not immediately express an opinion. After several days of consideration, he decisively made the call, letting this "intern researcher" take on the important technical task and giving him support in personnel and materials. In December 1964, Zhou Yuan led the team to successfully develop a helium liquefier pre-cooled by a new type of piston expander. In 1965, this new technology was promoted domestically, providing basic conditions for the rapid development of China's superconductivity and space technology.
In the 1990s, Hong Chaosheng (right) and Zhou Yuan in Hong Chaosheng's office. Photo provided by the Institute of Physics and Chemistry.
Zhao Zhongxian also marveled at Hong Chaosheng's vision. In 1964, after graduation, Zhao Zhongxian was assigned to Hong Chaosheng's research group at the Institute of Physics and soon became the youngest core member. He participated in the superconducting computer component development task organized by Hong Chaosheng, applying semiconductor lithography technology to the preparation of superconducting devices. Around 1998, physicist Yang Zhenning once asked Zhao Zhongxian: "Does the Institute of Physics have anyone working on ultra-low temperature and Bose-Einstein condensation research?" Zhao Zhongxian answered, "Someone is doing it." Bose-Einstein condensation is an important physical phenomenon that can appear only under ultra-low temperature experimental conditions. In fact, as early as the 1960s, under Hong Chaosheng's leadership, the Institute of Physics had achieved ultra-low temperatures. In 1980, it successfully developed a dilution refrigerator and carried out superconductivity research at ultra-low temperatures. Later, a group of people who transferred from the Institute of Physics to the Cryogenic Technology Experimental Center of the Chinese Academy of Sciences conducted ultra-low temperature physics research under his guidance. When Yang Zhenning asked, research on Bose-Einstein condensation at the Institute of Physics had already begun. "Mr. Hong's judgment of the future needs of national science was very forward-looking," Zhao Zhongxian said.
In 2017, after learning that Zhao Zhongxian (left) had won the State Preeminent Science and Technology Award, Hong Chaosheng, bedridden, held his hand and smiled happily. Photo provided by the Institute of Physics and Chemistry.
Hong Chaosheng the "Patriot"
Hong Chaosheng was frank and upright, and inevitably offended some people, but he was never afraid. Zhao Zhongxian said Hong Chaosheng possessed a "special character": "When his correct propositions were not accepted and his struggles yielded no results, he would take measures to minimize losses. What he insisted on fighting for was not for his own small turf, but for the long-term interests of the country."
This "special character" was especially clear when he made judgments. Whether to do something or not, he almost always used national interest as the standard, and this was related to his upbringing.
In 1931, when the September 18 Incident occurred, Hong Chaosheng was studying at Beijing Yuying Middle School. When his English teacher Mr. Cui and Mrs. Ren read reports about the incident from English newspapers in class, they could not help but burst into loud sobs, and immediately the whole classroom was filled with crying. That scene was unforgettable to Hong Chaosheng for the rest of his life.
In 1935, the December 9 anti-Japanese national salvation movement broke out. The 15-year-old Hong Chaosheng participated in a student march at Huiwen Middle School and, as a movement backbone, delivered a speech at a mobilization rally. His classmate Li Zongxi later called him a "little hero" in an autograph book.
In 1936, Hong Chaosheng was admitted to Tsinghua University. He originally wanted to study physics, but his father Hong Guantao firmly believed in "saving the country through engineering" and strongly opposed it. Helpless, he had to transfer to the Department of Electrical Engineering. After that, he spent his whole life thinking about and exploring how an intellectual could serve the country.
In 1937, the War of Resistance Against Japanese Aggression broke out in full force, and Tsinghua University moved south to Changsha. Hong Chaosheng and his classmates agreed to go to Yan'an, but several attempts failed. In early 1938, he made up his mind not to retreat again. When he reached Zhengzhou, however, he learned that he could not cross the blockade to northern Shaanxi and had to return dejectedly. Yan'an was a regret he could not fulfill in his entire life.
On October 1, 1949, New China was founded. Hearing the good news, Hong Chaosheng, far away on the other side of the ocean, found a piece of coordinate paper printed by Purdue University and, referring to the five-star red flag pattern and production instructions reprinted in the Chinese Overseas Daily, drew it stroke by stroke. He repeatedly calibrated the size ratio of each five-pointed star and every part of the flag layout until it fully met the standard. After finishing, he carefully treasured the flag pattern. He kept it for more than half a century.
In October 1949, the five-star red flag pattern hand-drawn by Hong Chaosheng while at Purdue University. Photo provided by the Institute of Physics and Chemistry.
This patriotic feeling ran through Hong Chaosheng's entire life. In the late 1990s, he went to Harbin to visit his elder sister Hong Jing. When he and his family walked to a hotel on Central Street, he saw the national flag hung upside down. Emotionally stirred, he rushed into the hotel to argue with the staff. The employee said, "We don't handle this. Go find the manager." He really did go to the second floor and negotiate with the manager. In his heart, the national flag is the symbol of the country and must not be desecrated. Anything that might harm national interests, no matter how big or small, he could not tolerate.
In 1986, one of his early students organized an academic conference, gave stainless steel tableware as gifts to participants, and arranged a trip to Huangshan after the meeting. When Hong Chaosheng learned of this, he was very angry and wrote a severe criticism: "We must focus on creating a socialist spiritual civilization for ourselves and future generations, and actively and unremittingly resist unhealthy trends, otherwise our country will have no future."
In his later years, Hong Chaosheng felt that he could do less for the country and tried to avoid causing trouble for his institute and the people around him. After retirement, he still worked but resolutely refused performance pay. He said, "I already receive a pension according to the standard for retirees. I don't want anything else." Later, because of difficulty moving, he went to the institute office less often and simply returned his original office to the institute to ease the shortage of office resources.
In his 90s, Hong Chaosheng underwent surgery after injuring his leg in a fall and was cared for by a caregiver. Once, Li Laifeng found the "old gentleman" scrubbing his socks in the bathroom by himself. When the caregiver wanted to wash them for him, he firmly refused. "Whatever he could do himself, he insisted on doing himself," Li Laifeng said.
In 2018, Hong Chaosheng passed away at the age of 98. Seeing some unhealthy trends in the scientific and technological community, staff at the institute did something that might have gone against the "old gentleman's" wishes during his lifetime—they turned the 20-square-meter office where he had worked into a small memorial hall. On the bookshelves are classified materials bearing his handwriting, and on the wall is the complete story of his life. After the memorial hall was arranged, Li Laifeng sat for a long while on the chair where Hong Chaosheng had sat during his lifetime. He whispered an explanation to the "old gentleman": "You yourself were a person of integrity and also hoped that we would be such people. Although this goes against your wishes and makes me look like a 'rebellious son,' we must give young people an example to learn from, right?"
Every year on the institute's open day, visitors come in an endless stream to see Hong Chaosheng's office. When Li Laifeng is not busy, he comes to guide everyone through the visit and tell stories about the "old gentleman" during his lifetime.
In 2024, the institute erected a statue of Hong Chaosheng, replicating his image in life: wearing a Zhongshan suit with the top button fastened tightly; eyebrows raised, and behind large, thick glasses, his gaze looking straight ahead without evasion, with a trace of sharpness; hair neatly parted and combed back, with a clear jawline making him appear vigorous. Below the statue, large golden characters are carved on black marble—"Hong Chaosheng."
This name was given to him by his father. "Chaosheng" means advancing toward a new life and a new world.
"Chaosheng," Hong Chaosheng did it.
Today's China already possesses an independent "super cryogenic factory" from liquid hydrogen to liquid helium, independent preparation capability for superconducting materials covering a complete industrial chain from development to application, and a team continuing forward on the road he opened.
And the three characters "Hong Chaosheng," no matter how much he wanted to erase them during his lifetime, have already melted into the galaxy of the republic, becoming a star that shines forever.
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