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Tổ chức Baccalaureate Quốc tế · IB Diploma · Design Technology · SL Chủ đề 2 2:07 Giọng đọc tiếng Anh · phụ đề tiếng Anh + 中文 được ghi trực tiếp
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These are selected topics, not the whole syllabus, and every example is fictional.
这些是精选主题，不是完整大纲，所有例子都是虚构的。
Every model answers one question; iteration revises a design from evidence gathered under equal conditions.
每个模型只回答一个问题；迭代是在相同条件下收集证据，再据此修改设计。
Manufacture produces a range of sizes, so a fit is checked at the worst-case limits.
制造得到的是一个尺寸范围，所以配合要在最坏情况的极限下检查。
A cardboard model can reveal reach and arrangement, but it cannot show the final material is strong enough.
纸板模型可以显示够及距离和布局，但不能证明最终材料足够结实。
A material prototype can be load tested for stiffness, but says nothing about appearance.
材料原型可以做载荷测试来检验刚度，但不能说明外观。
State what each model includes and omits.
要说明每个模型包含什么、省略了什么。
A beam prototype deflects 8 millimetres under a stated load.
梁的原型在规定载荷下挠度为 8 毫米。
The revision, tested under the same load and conditions, deflects 5 millimetres.
修改后的版本在相同载荷和条件下测试，挠度为 5 毫米。
The reduction is 3 out of 8, which is 37.5 percent.
减少了 8 的 3，即 37.5%。
That supports greater stiffness in this test, not every strength or fatigue property.
这支持本次测试中刚度更大，但不能证明所有强度或疲劳性能。
A hole is 10.0 plus or minus 0.2 millimetres, so it lies between 9.8 and 10.2.
孔是 10.0 ± 0.2 毫米，介于 9.8 和 10.2 之间。
A shaft is 9.5 plus or minus 0.1, between 9.4 and 9.6.
轴是 9.5 ± 0.1，介于 9.4 和 9.6 之间。
The minimum clearance is the smallest hole minus the largest shaft: 0.2 millimetres.
最小间隙 = 最小孔 − 最大轴 = 0.2 毫米。
The maximum is the largest hole minus the smallest shaft: 0.8.
最大间隙 = 最大孔 − 最小轴 = 0.8。
Every pair fits.
每一对都能装配。
Three parts sit end to end, and each may be 0.1 millimetres off.
三个零件首尾相接，每个可能偏差 0.1 毫米。
In the worst case all three err the same way, so the assembled length may be off by 0.3 millimetres.
最坏情况下三个都朝同一方向偏，装配长度可能偏差 0.3 毫米。
Tolerances stack along a chain, which is why assemblies specify the worst case.
公差沿链累加，所以装配要按最坏情况来规定。
Check yourself.
自我检测。
A fall from 10 to 6 millimetres is a 40 percent reduction.
从 10 毫米降到 6 毫米，减少 40%。
Appearance is not mechanical performance.
外观不等于力学性能。
Smallest hole 12.0 minus largest shaft 11.8 is 0.2 millimetres.
最小孔 12.0 减最大轴 11.8，等于 0.2 毫米。
Display resolution is not accuracy.
显示分辨率不等于准确度。