英 [ˌprəʊtækˈtɪniəm] 美 [ˌproʊtækˈtɪniəm]
n. [化学]镤（元素符号 Pa, 等于 protoactinium）
protactinium /ˌprəʊtækˈtɪnɪəm/
名词 a toxic radioactive metallic element that occurs in uranium ores and is produced by neutron irradiation of thorium. Symbol: Pa; atomic no: 91; half-life of the most stable isotope, 231Pa: 32 500 years; valency: 4 or 5; relative density: 15.37 (calc.); melting pt: 1572°C 镤 (Former name protoactinium)
a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
同义词： protoactinium / Pa / atomic number 91
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从辐照过的钍中分离镤的研究_stmopen 关键词】: 镤 钍 PMBP TIOA [gap=926]Keywords Protactinium Thorium PMBP TIOA
地质专业英语词汇P2 ... prostratigraphy 杩 原始地层学 protactinium 瑯 镄 protactinium 瑯 dating 镤年代测定法 ...
哒酮 pa 专业辞典【化学】元素镤(protactinium)的符号pa【物理学】压强单位帕斯卡(pascal)的符号pa (pis passe-droit 音标：[pasdrwa]m.
In color and fabric, is based on popular trends this year, chose to protactinium gather green camouflage fabric;
在色彩和面料上，是根据今年流行趋势，选择了返镤归真的绿色迷彩面料；
In particular the intermediate product protactinium-233 (Pa-233) is a neutron absorber which diminishes U-233 yield.
FORBES: Is Thorium the Biggest Energy Breakthrough Since Fire? Possibly.
The conversion is not direct, and involves the initial formation of thorium-233, which decays rapidly to protactinium-233, and then to uranium-233 over a period of about a month.
Hence presumably reprocessing is involved in the final stage, since if the protactinium-233 is left in the reactor it will be at least partly converted to protactinium-234, which is not a useful fissile material.