原子序数相差多少（核言碎语171）

126 原子序数密度Atomic Number Density，下面我们就来说一说关于原子序数相差多少?我们一起去了解并探讨一下这个问题吧!

原子序数相差多少

126 原子序数密度

Atomic Number Density

（http://www.nuclear-power.com/）

原子序数密度

The atomic number should not be confused with the atomic number density, which is a completely different physical quantity.

原子序数不应与原子序数密度混淆，原子序数密度是一个完全不同的物理量。

In nuclear physics, the macroscopic cross-section represents the effective target area of all of the nuclei contained in the volume of the material. The macroscopic cross-section is derived from microscopic cross-section and the atomic number density (N):

在核物理中，宏观截面表示材料体积中包含的所有原子核的有效目标面积。宏观截面由微观截面和原子序数密度（N）得到:

Σ=σ.N

The atomic number density plays a crucial role in this equation as the microscopic cross-section. In the reactor core, the atomic number density of certain materials (e.g., water as the moderator) can be simply changed, leading to certain reactivity changes. To understand the nature of these reactivity changes, we must understand the atomic number density term.

原子序数密度与微观截面一样，在这一方程中起着至关重要的作用。在堆芯中，某些物质（如水作为慢化剂）的原子序数密度可以简单地改变，从而导致某些反应性的变化。要理解这些反应性变化的本质，我们必须了解原子序数密度项。

The atomic number density (N; atoms/cm3) is the number of atoms of a given type per unit volume (V; cm3) of the material. The atomic number density (N; atoms/cm3) of a pure material having an atomic or molecular weight (M; grams/mol) and the material density (⍴; gram/cm3) is easily computed from the following equation using Avogadro’s number (NA = 6.022×10^23 atoms or molecules per mole):

原子序数密度（N;原子数/cm^3）是材料单位体积（V;Cm^3）的给定类型的原子数量。纯物质的原子序数密度（N;原子/cm^3），已知原子量或分子量（M;克/摩尔）和材料密度（⍴;克/cm^3），很容易用阿伏伽德罗常数（NA = 6.022×10^23每摩尔原子或分子）从下面的公式计算出来:

（待续）