裂变
国际文凭组织 · IB Diploma · 物理 · SL 知识点 18 4:36 英语旁白 · 英中内嵌字幕
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A neutron can trigger a heavy nucleus to split, releasing energy and further neutrons.
中子可以诱发重核裂变，释放能量并产生更多中子。
Whether the process becomes a chain reaction 链式反应 depends on what happens to those neutrons.
该过程是否形成链式反应，取决于这些中子的后续行为。
In nuclear fission, a heavy nucleus splits into lighter nuclei.
在核裂变中，重原子核分裂成较轻的原子核。
Proton number and nucleon number balance in a nuclear equation.
质子数与核子数在核反应方程中保持平衡。
The total rest mass can decrease; the difference corresponds to released energy through E equals delta m c squared.
总静止质量可能减少；其差值对应通过E等于delta m c平方释放的能量。
Fission is the splitting of a heavy nucleus into lighter nuclei.
裂变是指重原子核分裂为较轻原子核的过程。
A chain reaction is a sequence in which products initiate further events.
链式反应是指产物引发后续事件的序列。
Separate conservation of nucleon number from conservation of total energy.
将核子数守恒与总能量守恒分开考虑。
Released neutrons may initiate further fissions, escape or be absorbed.
释放的中子可能引发进一步的裂变、逃逸或被吸收。
A controlled reactor and an uncontrolled chain reaction have different neutron-management conditions.
受控反应堆与不受控链式反应具有不同的中子管理条件。
In the lab: Balance a supplied nuclear equation, use the specified mass data and identify the system.
在实验室中，配平给定的核反应方程。 使用指定的质量数据并识别系统。
Analyse models or published reactor data; this is not a school attempt to produce fission or handle reactor materials.
分析模型或已发表的反应堆数据。 这不是学校尝试产生裂变或处理反应堆材料。
Known. Uranium-235 absorbs one neutron, forming barium-141, krypton-92 and three neutrons.
已知：铀-235 吸收一个中子，生成钡-141、氪-92 和三个中子。
Nucleon balance; 235 plus 1 equals 141 plus 92 plus 3, which equals 236.
核子数平衡：235 加 1 等于 141 加 92 加 3，即 236。
Proton balance; 92 equals 56 plus 36.
质子数平衡：92 等于 56 加 36。
A mass decrease of 2.0 times 10 to the minus 28 kilograms corresponds to 1.8 times 10 to the minus 11 joules using c equals 3.0 times 10 to the 8 metres per second.
质量减少 2.0 乘以 10 的负 28 次方千克，对应 1.8 乘以 10 的负 11 次方焦耳，其中光速 c 取 3.0 乘以 10 的 8 次方米每秒。
Your turn: A U-235 nucleus plus one neutron produces fragments with mass numbers 141 and 92.
轮到你了。 一个铀-235原子核加一个中子，产生质量数分别为141和92的碎片。
How many neutrons balance the equation?
需要多少个中子才能使方程配平？
Pause the video and work it out.
请暂停视频，自己算一算。
Check: 235 plus 1 is 236, the fragments make 233, so 3 neutrons balance it.
核对：235 + 1 = 236，碎片共 233，所以需要 3 个中子。
Mass number is not a precise mass in kilograms.
质量数并非以千克为单位的精确质量。
Balanced integer labels alone do not calculate the released energy.
仅凭配平的整数标签无法计算释放的能量。
Radioactive decay and neutron-induced fission are not interchangeable descriptions.
放射性衰变与中子诱发裂变并非可互换的描述。
Not true.
不正确。
A balanced nucleon-number equation alone does not give the energy release in joules.
仅凭配平的质量数方程无法得出以焦耳为单位的能量释放。
Integer mass and charge labels only check conservation; they say nothing about energy.
整数质量数和电荷标签仅用于验证守恒，与能量无关。
The released energy comes from the small decrease in actual mass via E equals m c squared, which needs measured masses, not mass numbers.
释放的能量来自实际质量的微小减少，遵循E等于m乘c平方，这需要实测质量，而非质量数。
In nuclear fission, a heavy nucleus splits into lighter nuclei.
在核裂变中，重原子核分裂为较轻的原子核。
Separate conservation of nucleon number from conservation of total energy.
请将核子数守恒与总能量守恒区分开。
Watch for: mass number is not a precise mass in kilograms.
注意：质量数并非以千克为单位的精确质量。
A U-235 nucleus plus one neutron produces fragments with mass numbers 140 and 94.
一个铀-235原子核加一个中子产生质量数分别为140和94的碎片。
Find how many neutrons balance the nucleon number.
求多少个中子才能使核子数守恒。
That count is not the energy release in joules.
这个数量不是以焦耳为单位的能量释放量。
A uranium-235 nucleus absorbs a neutron and splits into two smaller nuclei. Two or three neutrons are released with a large amount of energy, and those neutrons can trigger further fissions.
铀235原子核吸收一个中子后分裂成两个较小的原子核，同时释放两到三个中子和大量能量，这些中子可以引发进一步的裂变。
For the nuclear reaction U-235 plus a neutron yields Ba-141 plus Kr-92 plus x neutrons, find the value of x and verify proton balance using atomic numbers 92, 56, and 36.
对于核反应铀-235加中子生成钡-141加氪-92加x个中子，求x的值，并利用原子序数92、56和36验证质子守恒。
Does nucleon conservation mean rest mass is unchanged?
核子数守恒是否意味着静止质量不变？
x is 3, and the protons balance: 92 equals 56 plus 36.
x 等于 3，质子数守恒：92 等于 56 加 36。
Nucleon number and charge balance, while binding-energy differences allow rest mass to become other energy.
核子数和电荷都守恒，而结合能的差别使一部分静止质量转化为其他形式的能量。
Pause and check yourself. Explain each point on screen in your own words, then change one number in the last example and say which assumption must still hold.
暂停一下，自我检查：用自己的话解释屏幕上的每个要点，再改动最后一个例子中的一个数字，说明哪个假设仍然必须成立。