| 释义 |
mesothorium Chem.|mɛsəʊˈθɔərɪəm, miːzəʊ-|
[mod.L. (O. Hahn 1907, in Ber. d. Deut. Chem. Ges. XL. 1469): see meso- and thorium.]
Either of two radioactive nuclides in the thorium decay series: mesothorium I (symbol MsThI), the isotope of radium with mass number 228, produced by the alpha decay of thorium 232, or mesothorium II (symbol MsThII), the isotope of actinium with mass number 228, produced by the beta decay of mesothorium I.
1907Jrnl. Chem. Soc. XCII. ii. 359 The suggestion is made that thorium is not directly transformed into radiothorium, but into an intermediate product, ‘Mesothorium’, which then yields radiothorium. 1935Jrnl. R. Aeronaut. Soc. XXXIX. 857 The mesothorium preparation produces a point source of gamma radiation suitable for the inspection of thick metal objects for which X-ray investigation becomes very expensive. 1937Nature 21 Aug. 318/1 Lemna [duckweed] accumulates mesothorium I and concentrates it a hundredfold as compared with its content in the water. 1969R. F. Lang tr. Henglein's Chem. Technol. 546 Mesothorium is present in monazite to the extent of 1 mg per t, and serves as a substitute for radium. |