It's the mass of one nucleon.

它是一个核子的质量。

Collectively, by the way, these particles are known as nucleons.

顺便说一下， 这些粒子统称为核子。

Nucleons remember are the protons and neutrons that we have inside the nucleus of an atom.

记住，核子是原子核内的质子和中子。

Nucleon number before and charge before has to equal nucleon number and charge after.

前的核子数和前的电荷必须等于后的核子数和电荷。

Because of this, we'll often refer the two particles collectively as nucleons.

因此，我们两种粒子的集合体当作原子核。

Because of this, we’ll often refer the two particles collectively as nucleons.

因此，我们把这些两个粒子统称为核子。

Topics that people use muons for range from fundamental constants of nature, basic symmetries, weak nucleon and nuclear interactions.

人们使用μ子研究的领域包括自然的基本数、基本对称性、弱核子和核相互作用。

The mass number is just the total number of nucleons in the nucleus, which is different from atomic mass.

质量数只是原子核中核子的总数， 它不同于原子质量。

Now, a unique part of beta decay is that no nucleons are emitted during the decay process.

现在，一个beta衰变的特别部分是当衰变产生时没有一个核子。

But even though those numbers of nucleons add up, remember: Mass and energy are equivalent.

但即便核中的数字被加总了，还是要记得：质能守恒。

And in radioactive decay nucleon number and charge before and after are going to be equal.

而在放射性衰变中，衰变前后的核子数量和电荷相等。

And then we know the number of nucleons is 235.

然后我们知道核子的数量是235。

And so it is not about the electrons anymore, it is about the nucleons themselves.

所以这不再与电子有关，而是与核子本身有关。

What is going to be our nucleon number here?

这里的核子数是多少？

The nucleon number before and after is exactly the same.

前后的核子数完全相同。

So conservation of nucleon number and charge will always exist in every nuclear reaction and also in radioactive decay, or nuclear decay.

因此，核子数和电荷的守恒在每个核反应中以及在放射性衰变或核衰变中始终存在。

Remember nucleon number is going to be the number of protons and neutrons.

记住核子数就是质子和中子的数量。

And so as it loses that it is losing four of these nucleons, these parts inside the nucleus.

而且当它失去这些时，它会失去四个这样的核子，也就是原子核内的这些部分。

While the strong force acts on nucleons, the weak force alters quarks, the fundamental particles that make up both protons and neutrons.

虽然强力作用于核子，弱力则改变夸克，而夸克是构成质子和中子的基本粒子。

What is going to be the nucleon number?

核子数是多少？