网站首页  英汉词典

请输入您要查询的英文单词:

 

单词 Primordial nucleosynthesis
释义

Primordial nucleosynthesis

中文百科

太初核合成 Big Bang nucleosynthesis

(重定向自Primordial nucleosynthesis)
The main nuclear reaction chains for Big Bang nucleosynthesis

太初核合成BBN)是物理宇宙学的一个概念,指宇宙在早期阶段产生H-1(最常见,也是最轻的氢同位素,只有单独的一个质子)之外原子核的过程。太初核合成在大霹雳之后只经历了几分钟,相信与一些较重的同位素的形成,如氘(H-2或D)、氦的同位素(He-3和He-4)、锂的同位素(Li-6和Li-7)的形成有密切的关系。除了这些稳定的原子核之外,还有一些不稳定的放射性同位素在太初核合成之际也形成了:氚(H-3)、铍(Be-7和Be-8)。这些不稳定的同位素不是蜕变就是融合成前述其它的稳定同位素。(所有这些原子核通常表示为X,此处X = 这些元素的标准名称,N = 原子量的数值,但是这儿将简单的标示为X-N。)

英语百科

Big Bang nucleosynthesis 太初核合成

(重定向自Primordial nucleosynthesis)
Full-sky image derived from nine years' WMAP data
The main nuclear reaction chains for Big Bang nucleosynthesis
A version of the periodic table indicating the origins – including big bang nucleosynthesis – of the elements. All elements above 103 (lawrencium) are also manmade and are not included.

In physical cosmology, Big Bang nucleosynthesis (abbreviated BBN, also known as primordial nucleosynthesis) refers to the production of nuclei other than those of the lightest isotope of hydrogen (hydrogen-1, H, having a single proton as a nucleus) during the early phases of the universe. Primordial nucleosynthesis is believed by most cosmologists to have taken place from 10 seconds to 20 minutes after the Big Bang, and is calculated to be responsible for the formation of most of the universe's helium as the isotope helium-4 (He), along with small amounts of the hydrogen isotope deuterium (H or D), the helium isotope helium-3 (He), and a very small amount of the lithium isotope lithium-7 (Li). In addition to these stable nuclei, two unstable or radioactive isotopes were also produced: the heavy hydrogen isotope tritium (H or T); and the beryllium isotope beryllium-7 (Be); but these unstable isotopes later decayed into He and Li, as above.

随便看

 

英汉网英语在线翻译词典收录了3779314条英语词汇在线翻译词条,基本涵盖了全部常用英语词汇的中英文双语翻译及用法,是英语学习的有利工具。

 

Copyright © 2004-2024 encnc.com All Rights Reserved
更新时间:2025/6/21 22:57:52