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- Alpha particles are positively charged helium nuclei obtained from natural radioactive decay. 粒子是从天然放射性蜕变得到的带正电的氦核。
- The immediate product of the radioactive decay of an element. 继承元素某种元素放射性衰变的直接产物
- natural radioactive decay 放射性自然衰变
- To disintegrate or diminish by radioactive decay. 衰变由于放射性衰变而解体或缩小
- No colour and no smell, arising from the decay of radium, is the only natural radioactive inert natural gas, the proportion is 7.5 times the air. 没有颜色也没有任何气味，由镭衰变而产生，是自然界惟一的天然放射性惰性气体，比重是空气的7.;5倍。
- Measurement of geologic time,as through isotopic radioactive decay. 地质年代测定是通过放射性同位素衰变来测定的。
- Radon and its daughters not only are the decay product of natural radioactive uranium series and thorium series, but also are one of natural radiation source. 氡及其子体是天然放射性系列中的铀系、钍系衰变产生的,是人类受天然辐射主要的来源之一。
- Two test methods, natural radioactive background method and decay method, used to verify the detection limit of radioactive aerosol monitors are studied. 两种方法不仅可检测监测仪的探测限,而且对各种监测仪探测限指标的物理意义能给以正确判断。
- Rutherford first identified the action of probability in radioactive decay. 卢瑟福首先认识到几率在放射性衰变中的作用。
- Any of several radioactive gases that are isotopes of radon and are products of radioactive decay. 射气几种氡的同位素的放射性气体，是放射性物质衰变的产物
- Measurement of geologic time, as through isotopic radioactive decay. 地质年代测定通过放射性同位素衰变来测定地质年代
- Rutherford first identified the action of probability in radioactive decay . 卢瑟福首先认识到几率在放射性衰变中的作用。
- Radioactive decay is still a major concern for the people in this area. 放射性衰变仍是这一领域人们的一个主要顾虑。
- An Investigation on Natural Radioactive Lev-els and Their Distribution in Liangshan Regi-on, Sichuan Province. 凉山州天然放射性水平及其分布
- However, some of the minerals contain xenon isotopes unlike those usually produced by radioactive decay of uranium. 然而，有些含氙同位素的矿物并非如此，是由铀的放射性衰变产生的。
- As a product from the uranium disintegration, radon is a natural radioactive idle gas. 氡是天然放射性惰性气体,是铀系衰变链中的一个衰变产物。
- Polonium is a naturally radioactive metallic element. 钋是一种具有天然辐射性的金属元素。
- The time required for half the nuclei in a sample of a specific isotopic species to undergo radioactive decay. 半衰期放射性样品的原子核经历一半放射性衰变所需要的时间
- This paper summarizes the quality assurance work of external exposure mea-surement for national survey of environmental natural radioactive level. 本文总结了全国环境天然放射性水平调查外照射测量的质量保证工作。
- A report is made on the results of analysis the content of natural radioactive nuclide in 33 samples of building stone commonly used in South Fujian. 报道闽南常用石材的33个样品中,天然放射性核素含量的分析结果,并按照国家有关石材产品分类标准进行划分。
