conservation of particles

• 粒子数的守恒

conservation of particles的用法和样例：

例句

1. The conservation of energy does not require that a system be isolated.
   能量的守恒并不要求系统必须是孤立的。
2. The conservation of angular momentum explains why disks are so prevalent in the universe.
   角动量的守恒解释了为什麽圆盘在宇宙中这麽普遍。