给定元素的所有同位素都含有相同的质子数，但它们的中子数不同，因此它们的原子质量也不同。
All the isotopes of a given element have the same number of protons, but differ in their number of neutrons, and hence in their atomic mass.
它是质子数加上中子数。
它等于质子数，加上中子数。
And it is equal to the sum of the number of protons plus the number of neutrons.
现在，看看中子数，我们要做的，是看到这左上方。
Now, to get to the number of neutrons, what we do is go up here to the upper left.
任何突然出现的过量中子数会加速裂变反应，增加反应堆能量输出。
Any sudden excess of neutrons will accelerate the fission reaction and increase the reactor's power output.
所以，我们可以间接得到中子数，因为我们知道质子数了。
So we get at the number of neutrons indirectly because we know the proton number here.
有相同的Z，相同的质子数，但是不同的A，也就是中子数不同。
They all have the same Z, the same proton number, but different A, which means number of neutrons varies.
讨论了在一个增殖系统引发一个持续裂变链所需要的平均中子数。
The average neutron population necessary for sponsoring a persistent fission chain in a multiplying system, is discussed.
PCR是一座反应堆的核中子数会在反应堆能量增加后增加或减少的衡量标志。
The power coefficient of reactivity (PCR) is a measure of whether a particular reactor's nuclear neutron population will tend to increase or decrease after an increase in the reactor's power.
现在，最后一件事是，因为中子没有净电子，我们可以改变中子数。
Now the last thing is that because the neutron has no net charge, we can change neutron number.
在一个同位素的原子中中子数减去质子数，同位数是放射性的指示。
The number of neutrons minus the number of protons in the atom of an isotope. isotopic number is an indication of radioactivity.
一个原子的总重量能够近似取决于这个原子核中的质子数和中子数之和。
The total mass of an atom is determined very nearly by the total number of protons and neutrons in its nucleus.
这表示你可以改变中子数，而不会改变它的化学特性，因为化学特性是由质子决定的。
This means you can vary the neutron number without changing chemical identity, because chemical identity is fixed by the proton.
同位素：一种化学元素的两个或多个类型，它们的原子核具有相同的质子数，而中子数却不同。
Isotope: One of two or more species of atoms of a chemical element having nuclei with the same number of protons but different Numbers of neutrons.
按照本文所提出的物理模型，只要计算的中子数足够多，其计算结果可完全在实验误差范围之内。
Adopting the physics mode given in this thesis, the accuracy of computed results is within experimental errors if the number of computed neutron is large enough.
目前已知的最大中子数是126,82个质子和126个中子组成了元素周期表中最重最稳定的同位素。
The highest known magic number for neutrons alone is 126. Lead, with 82 protons and 126 neutrons, is thus "doubly magic" and the heaviest stable isotope in the periodic table.
如果那是大于1，也就是说我们创造了，更多的中子，在一代里，相对于下一个，中子数增长，裂变速率也一样。
If it's greater than one, namely we produce more neutrons in one generation compared to the next the neutron population grows as does the fission rate.
同位素是存在于元素的变体，天然存在，同位素与元素具有相同的化学性质，但由于所含的中子数不同而重量不同。
These are naturally occurring variants of elements,which share the same chemical properties but have different weights because their nuclei contain different numbers of neutrons.
同位素是存在于元素的变体，天然存在，同位素与元素具有相同的化学性质，但由于所含的中子数不同而重量不同。
These are naturally occurring variants of elements, which share the same chemical properties but have different weights because their nuclei contain different Numbers of neutrons.
在各种钨同位素原子里有74质子，但有着不同的中子数。钨- 182有108个中子，而钨- 184有110个中子。
Isotopes of tungsten each have 74 protons in their atoms but different Numbers of neutrons - tungsten-182 has 108 neutrons, while tungsten-184 has 110.
我们已经使用了一个相对简单的词语，称为，中子的增殖系数，那就是K，如果K等于1，中子数，是稳定的，裂变速率也一样。
And we've used a relatively simplistic term called neutron Multiplication Factor which is the K that if the K equals one the neutron population is steady as is the fission rate.
这也就是PCR呈现负值会出现的情况。因为PCR负值的反应堆会自动限制穿越反应堆的中子数，所以会在短暂的能量增加后减慢增长速度。
This is where having a negative PCR is handy, because it automatically limits the number of neutrons flying through the reactor, so it damps itself down after a momentary power increase.
难以捉摸的量子力学表明，中子“太多”和“太少”有时会重叠出现，因而一些特定的元素没有稳定的同位素(或称变体，核内中子数不同)。
And the vagaries of quantum physics mean that "too many" and "too few" sometimes overlap, and there is thus no stable isotope (or variant, with fewer or more neutrons) of a particular element.
所以碳12，我们知道它有质子数，根据定义，那就是6，而电子数，12减6等于6，所以它有6个中子。
So carbon 12. We know that it has the proton number, by definition, is 6. And the neutron number, 6 from 12 is 6. So it has 6 protons and 6 neutrons.
具备6个质子和6个中子，碳原子数通常为12。
With six protons and six neutrons, carbon normally has an atomic number of 12.
在它们的原子核中质子数是相同的(这是一个元素定义性的特征)，但是中子的数量不同。
They have the same number of protons in their nuclei (this is the defining characteristic of an element), but different Numbers of neutrons.
在它们的原子核中质子数是相同的(这是一个元素定义性的特征)，但是中子的数量不同。
They have the same number of protons in their nuclei (this is the defining characteristic of an element), but different Numbers of neutrons.
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