单词 | 中子源 |
释义 | 〔radium〕A rare, brilliant white, luminescent, highly radioactive metallic element found in very small amounts in uranium ores, having 13 isotopes with mass numbers between 213 and 230, of which radium 226 with a half-life of 1,622 years is the most common. It is used in cancer radiotherapy, as a neutron source for some research purposes, and as a constituent of luminescent paints. Atomic number 88; melting point 700°C; boiling point 1,737°C; valence 2. See table at element 镭:一种稀有的、有白色光泽、发光、高度放射性的金属元素,极少量地存在于沥青矿中,有13种同位素,质量数介于213和230之间,最常见的为镭226,半衰期为1,622年。镭可用于癌症的放射治疗,在其它一些研究中用作中子源,还可用作发光颜料的成分。原子序数88;熔点700°C;沸点1,737°C;原子价2 参见 element |
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