When the total baryon number density is about 6 , neutrons and protons almost have the equal proportion, which leads to the symmetric nuclear matter.是什么意思_When the total baryon number density is about 6 , neutrons and protons almost have the equal proportion, which leads to the symmetric nuclear matter.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句