| 释义 |
cæsium Chem.|ˈsiːzɪəm|
Also (U.S.) cesium.
[f. L. cæsium, neuter of cæsius bluish grey.]
One of the elementary bodies; a rare alkali-metal discovered by spectrum-analysis in 1860–61 by Bunsen and Kirchhoff; so called from two distinctive lines in the spectrum given by its compounds. Symbol Cs. Used attrib., as in cæsium compounds; cæsium cell (see quot. 1940).
1861Lond. & Edinb. Philos. Mag. Ser. iv. No. 21. 86 A faint blue line not due to strontium or potassium or to the lately discovered cæsium. 1862Timbs Year-bk. of Facts 188 Cæsium and Rubidium. The new alkaline metals..described..in the Philosophical Magazine. 1864Lyell Inaug. Addr. in Reader 17 Sept. 358 It was necessary to evaporate fifty tons of water to obtain 200 grains of what proved to be two new metals..He (Professor Bunsen) named the first cæsium, from the bluish-grey lines which it presented in the spectrum. 1873Fownes Chem. 350 Caesium carbonate is soluble in absolute alcohol. 1931Engineering 16 Jan. 87/1 The new Osram monatomic caesium cell being the most suitable for white light. 1940Chambers's Techn. Dict. 125/2 Caesium cell, a photo-electric cell having a cathode consisting of a thin layer of caesium deposited on minute globules of silver; it is particularly sensitive to infra-red radiation. 1955Sci. News Let. 27 Aug. 131/1 Cesium is a heavier and more active relative of sodium and potassium. 1958C. C. Adams et al. Space Flight xiv. 346 Both rubidium and cesium have been considered as the propellant for the ion drive. 1958Times Rev. Industry July 25/2 Machines now in service are stated to be equivalent in power to Cobalt 60 sources of well over 100,000 curies, and, in the isotope Caesium 137, of about 500,000 curies. 1960Gloss. Atomic Terms (H.M.S.O.) 9 Caesium (137),..a long-lived (30 yr. half life) gamma-emitting radioactive isotope (caesium 137) is found in fission products, the ‘ash’ of nuclear reactors, and is used for cancer therapy in some hospitals..and for industrial radiography. |