number density的用法和样例：
例句
- The incompressibility of the fluid is determined by introduction of a so-called particle density number.
流体的不可压缩性是通过引人粒子数密度概念实现的。 - In strong magnetic fields, Proton density increases with the increasing of total baryon densities, while neutron number density decreases.
随着总粒子密度的增加质子粒子数密度增加，中子粒子数密度减小。
