A radioactive isotope of carbon , especially carbon14 放射性碳碳的一种放射性同位素,尤指碳14
Analyzing archaeological remains of bone and hair for their abundances of the stable isotopes of carbon and nitrogen ( carbon 13 and nitrogen 15 ) can provide information about a person ' s diet 从考古遗址出土的遗骸,分析骨头、毛发中碳13 、氮15等稳定同位素的丰度,可以得到有关饮食的资讯。
The molecules were acting like enzymes , and yet they were much , much smaller : the molecular weight of a taml is about 500 daltons ( a dalton is equal to one twelfth the mass of carbon 12 , the most abundant isotope of carbon ) , whereas the weight of horseradish peroxidase , a relatively small enzyme , is about 40 , 000 daltons 这些分子的作用方式很像酵素,不过远比酵素小得多:一个taml的分子量大约是500道尔顿( 1道尔顿等于氢原子的质量) ;相较之下,在酵素里算小的辣根过氧化酶,分子量就约有四万道尔顿。
百科解释
Carbon (C) has 15 known isotopes, from 8C to 22C, 2 of which (12C and 13C) are stable. The longest-lived radioisotope is 14C with a half-life of 5,700 years.