Lise Meitner
| Noun | 1. |  Lise Meitner - Swedish physicist (born in Austria) who worked in the field of radiochemistry with Otto Hahn and formulated the concept of nuclear fission with Otto Frisch (1878-1968) |
| 单词 | lise meitner | |||
| 释义 | Lise Meitner
Lise MeitnerMeitner, Lise(lē`zə mīt`nər), 1878–1968, Austrian-Swedish physicist and mathematician. She was professor at the Univ. of Berlin (1926–33). A refugee from Germany after 1938, she became associated with the Univ. of Stockholm and with the Nobel Institute at Stockholm. In 1917, working with Otto HahnHahn, Otto, 1879–1968, German chemist and physicist. His important contributions in the field of radioactivity include the discovery of several radioactive substances, the development of methods of separating radioactive particles and of studying chemical problems by the ..... Click the link for more information. , she isolated the most stable isotope of the element protactiniumprotactinium , radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600°C;; b.p. 4,026°C;; sp. gr. 15.37 (calculated); valence +4, +5. Protactinium is a malleable, shiny silver-gray radioactive metal. ..... Click the link for more information. ; she also investigated the disintegration products of radiumradium [Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; mass number of most stable isotope 226; m.p. 700°C;; b.p. 1,140°C;; sp. gr. about 6.0; valence +2. Radium is a lustrous white radioactive metal. ..... Click the link for more information. , thoriumthorium [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750°C;; b.p. about 4,790°C;; sp. gr. 11.7 at 20°C;; valence +4. Thorium is a soft, ductile, lustrous, silver-white, radioactive metal. ..... Click the link for more information. , and actiniumactinium [Gr.,=like a ray], radioactive chemical element; symbol Ac; at. no. 89; mass number of most stable isotope 227; m.p. about 1,050°C;; b.p. 3,200°C;±300°C;; sp. gr. 10.07; valence +3. Actinium is a silver-white metal with a cubic crystalline structure. ..... Click the link for more information. and the behavior of beta rays. In 1938 she participated in experimental research in bombarding the uranium nucleus with slow-speed neutrons. Meitner interpreted the results as a fission of the nucleus and calculated that vast amounts of energy were liberated. Her conclusion contributed to the development of the atomic bomb. In 1949, she became a Swedish citizen. The element with the atomic number 109 is named meitneriummeitnerium , artificially produced radioactive chemical element; symbol Mt; at. no. 109; mass number of most stable isotope 276; m.p., b.p., sp. gr., and valence unknown. Situated in Group 9 of the periodic table it is expected to have properties similar to those of iridium. ..... Click the link for more information. in her honor. BibliographySee biography by R. L. Sime (1996); P. Rife, Lise Meitner and the Dawn of the Nuclear Age (1997). Meitner, LiseBorn Nov. 7, 1878, in Vienna; died Oct. 27, 1968, in Cambridge. Austrian physicist. Meitner was educated at the University of Vienna, where she received her Ph. D. degree in 1906. Beginning in 1907 she conducted scientific studies (as a guest) at the laboratory of O. Hahn in Berlin. From 1912 to 1915 she was an assistant at the Institute of Theoretical Physics. From 1917 to 1938 she was head of the physics section at the Kaiser Wilhelm Institute for Chemistry at Dahlem. From 1922 she taught at the University of Berlin, where she was appointed a professor in 1926. In 1938 she emigrated to Sweden, becoming a colleague at the Nobel Institute; in 1947 she was appointed a professor at the Higher Technical School in Stockholm. After her retirement in 1960, she lived in Great Britain. Meitner’s principal works were in nuclear physics. Together with Hahn, she developed a method of separating alpha decay products (1909) and established the presence of monochromatic groups in the spectra of beta rays (1911), showing that they are the result of the internal conversion of gamma rays. She and Hahn also discovered the radioactive element protactinium (1918). Between 1922 and 1924 she developed the concepts of the discrete energy states of the nucleus. In the 1930’s she began studying the nuclear reactions that occur when uranium is bombarded with neutrons. In 1939, together with O. Frisch, she gave a theoretical explanation of the experiments conducted by Hahn and F. Strassmann that revealed the presence of barium in the nuclear decay products of uranium. REFERENCECrawford, D. Lise Meitner, Atomic Pioneer. New York, 1969.Lise Meitner
Synonyms for Lise Meitner
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