“carbon dating”的概念、定义、习题解题方法及翻译-物理辞典

单词	carbon dating
释义	carbon dating(radiocarbon dating) A method of estimating the ages of archaeological specimens of biological origin. As a result of cosmic radiation a small number of atmospheric nitrogen nuclei are continuously being transformed by neutron bombardment into radioactive nuclei of carbon–14: ₇¹⁴N + n →₆¹⁴C + p Some of these radiocarbon atoms find their way into living trees and other plants in the form of carbon dioxide, as a result of photosynthesis. When the tree is cut down photosynthesis stops and the ratio of radiocarbon atoms to stable carbon atoms begins to fall as the radiocarbon decays. The ratio ¹⁴C/¹²C in the specimen can be measured and enables the time that has elapsed since the tree was cut down to be calculated. The method has been shown to give consistent results for specimens up to some 40 000 years old, though its accuracy depends upon assumptions concerning the past intensity of the cosmic radiation. The technique was developed by Willard F. Libby (1908–80) and his coworkers in 1946–47
随便看	thermal conductivity thermal diffusion thermal equilibrium thermal expansion thermal imaging thermal neutrons thermal reactor thermalization thermionic emission thermionic valve thermionics thermistor thermite thermochemistry thermocouple thermodynamic temperature thermodynamics thermoelectricity thermograph thermography thermoluminescence thermoluminescent dating thermometer thermonuclear reaction thermonuclear reactor

物理辞典收录了3346条物理词条，基本涵盖了常用物理知识及物理英语单词词组的翻译及用法，是物理学习的有利工具。