Xiao Lun is an expert in radiochemistry and isotope technology. People in Pixian County, Sichuan Province. 1939 graduated from Tsinghua University with a bachelor's degree. 195 1 received a doctorate from Illinois state university. Researcher of China Institute of Atomic Energy, Senior Consultant of Science and Technology Committee of China National Nuclear Corporation, Honorary President of China Isotope Society and Doctoral Supervisor. 1980 was elected member (academician) of Chemistry Department of China Academy of Sciences. 1957 Join the Jiu San Society.
Tantalum-183, tantalum-185 and tungsten-185m were found in the doctoral thesis. In the study of surface chemistry, the National Petroleum Energy Research Institute of the United States found that polyoxyethylene nonionic detergent had a positive charge in the solution. 1956 the first lecture on radiochemistry was held in Peking University. During the development of nuclear technology in China, he directed the development of special military radioactive sources and tritium, the raw material of hydrogen bombs. He has been engaged in the research, development, production and application of civil radioisotopes for a long time, such as neutron activation analysis of human nails and traditional Chinese medicine, labeling receptor imaging agents, etc.
Detailed life:
Xiao Lun was born in Pixian County, Sichuan Province, a land of plenty,1911215. His father used to be a scholar, and his mother knew books and manners. Xiao Lun grew up in a well-educated family. Xiao Lun was smart and diligent since he was a child, and he loved reading. When he was a child, he could write poems correctly. 1923, Xiao Lun was admitted to Chengdu Dacheng Middle School from a private school. 1926 graduated from middle school, and was admitted to the preparatory course of science of Chengdu university with excellent results. 1933 was admitted to the chemistry department of Tsinghua University, and dropped out of school due to illness. He graduated from the Chemistry Department of Tsinghua University on 1939. In the same year, he was admitted to the Biology Department of Peking University. A year later, I gave up graduate school and went back to Sichuan to raise money to run an alcohol factory.
1945 On the eve of War of Resistance against Japanese Aggression's victory, the United States dropped an atomic bomb on Hiroshima, which shocked the world and shocked Xiao Lun's heart. He is determined to develop China's atomic energy industry, and China will also produce atomic bombs. So, 1946, he decided to go abroad to study atomic energy science and technology, and went to the United States to study at his own expense with the second place in the country. 1947 went to the United States to study radiochemistry at the University of Illinois. 1948 obtained a master's degree from the University of Illinois. 195 1 year, Xiao Lun took the discovery of several new radioisotopes as the content of his thesis, passed the defense of his doctoral thesis, and obtained his doctorate. In Xiao Lun's research work, concentrated stable nuclides were bombarded with 22 MeV gamma rays. Through (γ, n) or (γ, p) reaction, according to the half-life, radiation energy, spin, log ft and decay outline of the reaction product nucleus, 185mW, 183Ta, 65438 were found. 183Ta is generated by 184W(γ, p) 183Ta, and 185Ta is derived from 186W(γ, p) 185Ta. Xiao Lun found that when the target 186WO3 was bombarded by gamma rays, besides 185Ta with a half-life of 46 minutes, there was stronger β radioactivity with a half-life of about 2 minutes. He also bombarded 184WO3 with γ-rays, the same weight as 186WO3, and obtained this short half-life β radioactivity, but it was much weaker than that obtained by enriching 186WO3. He doesn't feel like English F? d？ s？ Butement's idea comes from 15O generated by the reaction of 16O(γ, n), but it seems to be a kind of radioactivity obtained by (γ, n) from the low abundance of 186W in the tungsten target enriched with 184W. 15O emits β+,and the neutron-poor radioactivity obtained from (γ, n) should emit β-. Xiao Lun confirmed that the short half-life radioactivity of less than 2 minutes is 185mW of the converted electrons emitted from the deflection orientation of β by adding a magnetic field to the vertical surface of the vertical counter. In order to prove the correctness, Xiao Lun irradiated the reactor with concentrated 184WO3 for 1-2 minutes. 184W was mainly generated by (n, γ) reaction, and the 75-day half-life of the generated 185W was very small. The half-life of 185mW is determined as 1? 85 0? 15 minutes, now 1? Seven minutes. After receiving a doctorate in chemistry, Xiao Lun transferred to the Department of Physics of the University of Illinois to engage in nuclear science research. He was the first successful "alchemist" in China when he bombarded mercury with gamma rays on the world's largest accelerator to get radioactive gold -20 1. Soon after, Xiao Lun went to the US Bureau of Mines to study the application of radioactive tracers in secondary oil exploitation. One of the secondary oil recovery methods at that time was to replace the oil attached to the rock formation with surfactant solution. Xiao Lun used radiolabeled surfactants to study their adsorption and displacement properties. Nonionic detergent was considered to be the most suitable surfactant at that time. He studied the adsorption of nonionic detergent by radioactive tracer method, spectrophotometry and surface tension method. The results show that they are not exactly the same, but they are generally similar. This shows that radioactive tracer method can be used to study the adsorption of nonionic detergent. In the study of applying surface tension, Xiao Lun found an important abnormal phenomenon that molecular micelles of nonionic detergents are positively charged in aqueous solution. This result is often cited in monographs and literature.
From 65438 to 0955, Xiao Lun gave up his generous living and working conditions in the United States, broke through the obstruction of the American government and returned to the motherland. He has been engaged in radiochemistry and radioisotope research in Institute of Physics, Chinese Academy of Sciences, Institute of Atomic Energy, China Academy of Sciences, 40 1 of Second Machinery Department, and China Institute of Atomic Energy, Nuclear Industry Corporation.
Xiao Lun made a systematic study on the growth law of radioactivity. He found that when the mother's half-life increased from less than her daughter's half-life to equal to and greater than or even close to infinity, the total curve went through a straight-line stage, from convex to concave, to X axis, and even parallel to X axis. When the mother's half-life is 1/2 of the daughter's half-life, the total curve is a straight line, not a convex X axis less than the daughter's half-life. When the maternal half-life is greater than 1/2, but still less than the offspring half-life, the total curve is concave to the X axis but not convex to the X axis. Only when the maternal half-life is less than the half-life of 1/2 progeny, the total curve is convex to the X axis. He corrected the mistakes in the previous literature and the inaccuracies and incompleteness in the literature.
Xiao Lun and his collaborators have done a lot of work in the applied research of radioanalytical chemistry. In 1980s, Xiao Lun determined the essential trace elements in some traditional Chinese medicines by instrumental neutron activation analysis. It is found that zinc is the essential trace element with the highest content in cold medicines such as rhinoceros horn, antelope horn and substitute buffalo horn. Iron is the most important trace element in tonics such as Radix Astragali, Radix Angelicae Sinensis and Ginseng. Subsequently, 30 kinds of traditional Chinese medicines (24 of which are tonics) were analyzed by proton-excited X-ray fluorescence (PIXE) and processed by nonlinear mapping algorithm. It was found that 20 tonics were in the same area, of which 19 were together, and the other was a little farther away. Six non-tonic drugs are scattered in another area. Although tonics and non-tonics can be basically distinguished, the four tonics have entered the dispersed area of non-tonics. Xiao Lun and others used multivariate statistical methods to process PIXE data. According to the multivariate average test, within 95% confidence, the two types of Chinese medicines are different. Q- clustering method is almost the same as nonlinear mapping method except for four kinds of traditional Chinese medicines.
In 1980s, Xiao Lun and others also analyzed the contents of trace elements in Antarctic ice. Antarctica is the continent least affected by human activities. By studying the different depths of ice covered on it, we can get some information for thousands of years and tens of thousands of years. Xiao Lun et al. used instrumental neutron activation analysis method to analyze the content of 14 trace elements in ice samples at the depth of 430m from the Lodom ice sheet in Antarctica. The results show that in the past 5000 years, the environmental pollution of other continents has little impact on Antarctica. Seven elements, such as iron and aluminum, mainly come from the earth's crust, while sodium and magnesium come from the ocean. The other five volatile elements (or their compounds) have high enrichment coefficients, which may be the result of high temperature processes (such as volcanic eruption and combustion). The enrichment coefficients of these 14 elements are similar to those in the Antarctic atmosphere, indicating that the elements in Antarctic ice come from the atmosphere. The contents of these elements in Antarctic ice also reflect the contents of corresponding elements in the atmosphere. This work is a meaningful exploration for studying the changes of elements in the Antarctic atmosphere and whether modern environmental pollution in other continents has an impact on Antarctica.
Xiao Lun actively advocates and promotes the wide application of isotopes in non-nuclear sectors such as science, technology, medicine and agriculture, and has played a very good role in isotope application in these sectors. His projects "Tritium Process Research, Design and Production" and "Plutonium -2 10 and Preparation of Various Radioactive Sources" have made important contributions to national defense construction and won the National Science Conference Award of 1978.
After Xiao Lun returned to the motherland from 65438 to 0955, he mainly focused on the research of radiochemistry and radioisotopes. At the same time, he has served as director of Chinese Chemical Society, vice chairman of China Atomic Energy Society, executive director of China Nuclear Society and director of science popularization committee, member of Science and Technology Committee of Ministry of Nuclear Industry and head of isotope professional group, member of Pharmacopoeia Committee of Ministry of Health, vice chairman of China Society of Nuclear Chemistry and Radiochemistry, first deputy editor of Journal of Nuclear Chemistry and Radiochemistry, and concurrently served as professor of technical physics department of Peking University, senior consultant of Science and Technology Committee of Nuclear Industry Corporation, chairman of China Isotope Society and editor-in-chief of Isotope magazine, Shanghai Institute of Nuclear Research of China Academy of Sciences and H.
Xiao Lun, as an important radiochemist and pioneer of radioisotope in China, has always placed high hopes on young and middle-aged scientific and technological workers. His poem: "Clivia sat in front, scratching and chanting." If something is not enough, no official is light. The cause is earth-shattering, and its reputation spreads far and wide. I couldn't do it all the time, so I left it in the middle of the year. He accurately expressed his ardent hope for young and middle-aged people to develop radiochemistry and various scientific undertakings in China.
On June 65438+1October 65438+May 2000, Academician Xiao Lun passed away in Beijing.