The density value of heavy water 25C is not only the detection standard of heavy water grade (see American ASTM), but also the competitive object that international scholars try to measure accurately. Therefore, it is difficult to accurately determine the abundance of hydrogen isotopes and slightly oxygen-enriched isotopes by mass spectrometry. He and his assistant used ingenious experimental design to make the numerical value accurate to seven significant figures, which was one of the three best measurements in the international period of 1975 ~ 1985.
Professor Zhang Qinglian has made outstanding contributions in determining the relative atomic mass. 1983 was elected as a member of the International Atomic Weight Committee. By 2005, the new values of relative atomic mass of ten elements, such as indium, iridium, antimony, europium, cerium, erbium, germanium, zinc and dysprosium, which he presided over, were adopted as new international standards by the International Atomic Weight Committee.
199 1 year, the accurate atomic weight of indium determined by Zhang Qinglian isotope mass spectrometry is114.818 0.003, which adds a new number to the international atomic scale. This is the first time in the world to use the atomic weight data measured by China as the standard data. People think that this not only shows that the scientific level of China people is internationally competitive, but more importantly, it has set an ambition for the people of China. Zhang Qinglian also has many high-level research achievements in the field of rare elements. 1933 published the synthesis of five new selenite complexes, which is the first coordination chemistry paper in China. He also added the detection of rhenium to Noyce's masterpiece "Qualitative Analysis System of Rare Elements" (1927). He first made a systematic experiment to determine the position of rhenium in the copper telluride family, and then precipitated rhenium into rhenium disulfide in the filtrate of iridium and rhodium precipitation, and identified it in the form of rubidium rhenate. The content of rhenium in each layer and various elements that may interfere were determined. This method can detect 0.02% rhenium. In 1980s, Zhang Qinglian synthesized two new lithium halide complexes, both of which have the crystal structure of five-coordinated lithium, breaking through the viewpoint that lithium is only in even coordination.
In recognition of Zhang Qinglian's fruitful scientific research achievements in many aspects, the Chinese Chemical Society held a congratulatory meeting on his 50-year chemical work at 1985. Lu Jiaxi, Liu Gang and many other chemists went to give speeches and congratulations. 1989, China Academy of Sciences awarded him the honorary certificate of "Fifty Years of Scientific Work".
Zhang Qinglian is upright and cheerful, strict with himself, tolerant of others, rigorous in his studies and brave in exploration. Love the motherland, be loyal to education, work hard, regardless of fame and fortune. He has a wide range of knowledge and interests, including literature, art, gardening, calligraphy, sports, tourism and so on. Follow your own creed all your life and contribute to the accumulation of human civilization.
65438+February, 2006 14 19: 03, a famous chemist and educator, a senior academician of China Academy of Sciences, the founder of stable isotope chemistry in China, a professor at the School of Chemistry and Molecular Engineering of Peking University, and an outstanding producer of China, Mr. party member Zhang Qinglian died in Beijing at the age of 99.