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• a radioactive nuclide (Oxford)
• a radioactive nuclide (Merriam-Webster)
• radioactive isotope (radioisotope): any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays (EB)
particle or particles or divides into smaller nuclei (Oxford) • 原子核自发的结构或能量转变过程
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α衰变
Alpha decay
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α衰变的定义
• 放射性原子核自发放出α粒子而变为另一种 原子核的过程
• type of radioactive disintegration in which some unstable atomic nuclei dissipate excess energy by spontaneously ejecting an alpha particle
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Pierre Curie
• born May 15, 1859, Paris, France died April 19, 1906, Paris
• French physical chemist and cowinner of the Nobel Prize for Physics in 1903. He and his wife, Marie Curie, discovered radium and polonium in their investigation of radioactivity.
第三章 放射性核素的衰变规律
Radioactive decay
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目的
• 熟悉各种衰变的特点 • 掌握衰变规律与活度计算 • 了解放射性平衡及放射系
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• α衰变 • β衰变 • γ衰变 • 衰变规律 • 放射性平衡 • 放射系
内容
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引言
• 放射性的发现：贝可勒尔与居里夫妇 • 放射线的分类及本质 • 放射性与放射性核素的概念 • 自发的含义 • 核衰变的概念与分类 • 各种放射性核素通过衰变趋向β稳定线 • 对各类衰变，要求熟悉其含义、方程、对
• property exhibited by certain types of matter of emitting energy and subatomic particles spontaneously. It is, in essence, an attribute of individual atomic nuclei. (EB)
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Marie Curie
• born Nov. 7, 1867, Warsaw, Poland, Russian Empire died July 4, 1934, near Sallanches, France
• Polish-born French physicist famous for her work on radioactivity and twice a winner of the Nobel Prize. With Henri Becquerel and her husband, Pierre Curie, she was awarded the 1903 Nobel Prize for Physics. She was then sole winner of the 1911 Nobel Prize for Chemistry. She was the first woman to win a Nobel Prize
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（核，放射性）衰变(decay, disintegration)
• 原子核自发放出α、β、γ等粒子的过程 • (of a substance etc.) undergo change by
radioactivity (Oxford) • any process in which a nucleus emits a
• Note: a major source of heat in the interior of both the Earth and the Moon is provided by radioactive decay. (EB)
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放射性核素(radionuclide)
• 具有放射性的核素
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放射线的分类及本质
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放射性(radioactivity)
• 原子核自发放出α、β、γ等粒子的性质
• the spontaneous disintegration of atomic nuclei, with the emission of usu. penetrating radiation or particles (Oxford)
• α粒子的实质：高速运动的氦原子核
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α衰变的方程
或：
A Z
XAZ42Y
α
A Z
XAZ42Y
4 2
He
• Baidu Nhomakorabea：
222 86
Rn
218 84
Po
α
注：衰变过程满足质量数守恒、电荷守恒、 能量守恒以及动量守恒
象、能量和纲图
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Henri Becquerel
• 1852~1908, France
• French physicist who discovered radioactivity through his investigations of uranium and other substances. In 1903 he shared the Nobel Prize for Physics with Pierre and Marie Curie
