📚 Pre-U AQA Engineering: Essential Terminology Memorisation Guide | Pre-U AQA 工程：词汇术语速记指南
Mastering the specialist vocabulary is one of the most effective ways to boost your confidence and performance in the Pre-U AQA Engineering examination. This guide breaks down key terms from materials science, mechanics, electronics, and systems into memorable clusters, complete with quick memory tricks and bilingual explanations. Whether you are revising for Structured Questions or tackling the synoptic paper, a solid command of technical language will help you express ideas with precision.
掌握专业词汇是提升 Pre-U AQA 工程考试信心与成绩的最有效途径之一。本指南将材料科学、力学、电子学和系统等领域的关键术语分成便于记忆的模块，并配有巧记技巧和中英对照解释。无论你是在准备结构化问答题，还是应对综合试卷，扎实的技术语言功底都能帮助你精准阐述观点。
1. Stress and Strain | 应力与应变
Stress is defined as the force applied per unit area, typically expressed in pascals (Pa). In engineering, we distinguish between tensile stress, compressive stress and shear stress. The formula for direct stress is σ = F / A, where F is the force in newtons and A is the cross‑sectional area in square metres.
应力定义为单位面积上所受的力，通常以帕斯卡（Pa）表示。在工程中，我们区分拉伸应力、压缩应力和剪切应力。正应力的公式为 σ = F / A，其中 F 是以牛顿为单位的力，A 是以平方米为单位的横截面积。
Strain is the measure of deformation representing the relative displacement of particles in the material. Tensile strain is extension per unit length, a dimensionless ratio, given by ε = ΔL / L₀.
应变是衡量形变的量，表示材料内粒子的相对位移。拉伸应变是单位长度的伸长量，是一个无量纲的比值，公式为 ε = ΔL / L₀。
Memory aid: Stress is the ’cause’ (force applied), and strain is the ‘effect’ (how much it stretches). Think ‘Stress → Stretch → Strain’.
记忆技巧：应力好比“原因”（施加的力），应变则是“结果”（拉伸的程度）。记住“应力引起拉伸，产生应变”的思路。
2. Material Properties I – Stiffness, Strength and Hardness | 材料性能 I – 刚度、强度与硬度
Stiffness is a material’s resistance to elastic deformation. It is quantified by the Young modulus E, which is the slope of the stress–strain curve in the linear region. A high E means the material is difficult to stretch or bend elastically.
刚度是材料抵抗弹性变形的能力。它由杨氏模量 E 来量化，即应力–应变曲线线性段的斜率。E 值高意味着材料难以被弹性拉伸或弯曲。
Strength refers to the maximum stress a material can withstand before failure. The yield strength marks the onset of permanent deformation, while the ultimate tensile strength is the peak stress on the curve.
强度指材料在失效前所能承受的最大应力。屈服强度标志着永久变形的开始，而极限抗拉强度是曲线上的峰值应力。
Hardness is the resistance to surface indentation or scratching, often tested by Brinell, Vickers or Rockwell methods. It is closely related to wear resistance.
硬度是抵抗表面压痕或划伤的能力，通常通过布氏、维氏或洛氏硬度法测试。它与耐磨性密切相关。
Memory trick: Stiffness = how ‘stubborn’ the material is to change shape elastically; Strength = how ‘strong’ it is before breaking; Hardness = how ‘hard’ it is to scratch the surface.
巧记：刚度是材料弹性变形时的“犟脾气”；强度是断裂前的“强壮程度”；硬度是表面的“硬气”，不怕划伤。
3. Material Properties II – Toughness, Ductility and Brittleness | 材料性能 II – 韧性、延性与脆性
Toughness measures the energy absorbed before fracture, represented by the area under the stress–strain curve. A tough material can withstand both high stress and significant strain before breaking.
韧性衡量断裂前吸收的能量，用应力–应变曲线下方的面积表示。韧性好的材料在断裂前既能承受高应力，也能承受较大的应变。
Ductility is the ability to undergo large plastic deformation before rupture, often expressed as percentage elongation or reduction in area. Gold, copper and mild steel are highly ductile.
延性指材料在断裂前发生大量塑性变形的能力，通常用伸长率或断面收缩率表示。金、铜和低碳钢具有很高的延性。
Brittleness is the opposite: brittle materials fracture with little or no plastic deformation. Glass, ceramics and some cast irons are typical examples.
脆性则恰恰相反：脆性材料在几乎没有塑性变形的情况下断裂。玻璃、陶瓷和某些铸铁是典型例子。
Mnemonic: ‘Tough takes a beating, Ductile draws out, Brittle breaks without a shout.’
助记顺口溜：韧性能挨打，延性能拉长，脆性一打就断不嚷嚷。
4. Mechanical Behaviour: Fatigue, Creep and Fracture | 力学行为：疲劳、蠕变与断裂
Fatigue is the progressive, localised structural damage that occurs when a material is subjected to cyclic loading. The fatigue limit (or endurance limit) is the stress below which failure does not occur for any number of cycles.
疲劳是材料在循环载荷作用下发生的渐进性、局部结构性损伤。疲劳极限（或持久极限）是指在此应力以下，无论多少个循环都不会发生失效的应力值。
Creep is time‑dependent permanent deformation under constant load, particularly at elevated temperatures. The creep curve typically shows primary, secondary and tertiary creep stages.
蠕变是在恒定载荷下随时间增长的永久变形，尤其在高温下显著。蠕变曲线通常显示初始、稳态和加速蠕变三个阶段。
Fracture toughness is the material’s resistance to crack propagation, given by the critical stress intensity factor K₁c. It is vital for assessing safety in structures.
断裂韧性是材料抵抗裂纹扩展的能力，用临界应力强度因子 K₁c 表示。它对评估结构安全性至关重要。
Tip: Link the ‘cyclist’ to fatigue – a cyclist repeatedly pedals, just as cyclic loads cause fatigue. For creep, think of a slow ‘creep’ of time.
技巧：将“骑自行车的人(cyclist)”与疲劳联系起来——骑车人重复踩踏，正如循环载荷导致疲劳。蠕变则想象时间缓慢“爬行(creep)”。
5. Thermal Properties and Heat Transfer | 热学性能与传热
Thermal conductivity k is a material’s ability to conduct heat. Metals typically have high k, while polymers and ceramics have low k, making them good insulators.
热导率 k 是材料传导热量的能力。金属通常具有高 k 值，而聚合物和陶瓷具有低 k 值，因此是良好的绝热体。
Specific heat capacity c is the energy required to raise the temperature of 1 kg of a substance by 1 °C. It determines how much heat a material can store.
比热容 c 是将 1 kg 物质升高 1 °C 所需的能量。它决定了材料能储存多少热量。
Heat transfer occurs by conduction (direct contact), convection (fluid motion) and radiation (electromagnetic waves). The rate equation for conduction is Fourier’s law: q = −k A (dT/dx).
热量传递通过热传导（直接接触）、对流（流体运动）和热辐射（电磁波）发生。热传导的速率方程是傅里叶定律：q = −k A (dT/dx)。
Remember: ‘Conduction needs touch, Convection needs fluid, Radiation needs nothing in between.’
记住：“传导需要接触，对流需要流体，辐射什么都不需要。”
6. Electrical Concepts: Current, Voltage and Resistance | 电学概念：电流、电压与电阻
Electric current I is the rate of flow of charge, measured in amperes (A). Conventional current flows from positive to negative, opposite to electron flow.
电流 I 是电荷的流动速率，单位为安培（A）。习惯电流方向是从正极流向负极，与电子流动的方向相反。
Voltage (potential difference) V is the energy per unit charge transferred between two points, measured in volts (V). It is the ‘push’ driving current through a circuit.
电压（电势差）V 是两点间每单位电荷转移的能量，单位为伏特（V）。它是驱动电流通过电路的“推动力”。
Resistance R opposes current flow and is defined by Ohm’s law as R = V / I. Resistivity ρ is a material property: R = ρL / A, where L is length and A is cross‑sectional area.
电阻 R 阻碍电流流动，根据欧姆定律定义为 R = V / I。电阻率 ρ 是材料属性：R = ρL / A，其中 L 是长度，A 是横截面积。
Memory aid: Visualise a water circuit – current is water flow, voltage is water pressure, resistance is pipe friction.
记忆技巧：将电路想象成水路——电流是水流，电压是水压，电阻是管道摩擦力。
7. Semiconductors and Diodes | 半导体与二极管
Intrinsic semiconductors like pure silicon have a small number of charge carriers. Doping creates extrinsic semiconductors: n‑type with extra electrons (e.g. phosphorus in silicon) and p‑type with holes (e.g. boron in silicon).
本征半导体（如纯硅）具有少量电荷载流子。掺杂可制成非本征半导体：n 型含有额外电子（例如硅中掺磷），p 型含有空穴（例如硅中掺硼）。
A p–n junction forms a diode, which allows current to flow easily in one direction (forward bias) but blocks it in reverse. The threshold voltage for silicon diodes is about 0.7 V.
p–n 结构成二极管，它允许电流在一个方向（正向偏置）容易通过，但反向阻断。硅二极管的阈值电压约为 0.7 V。
Zener diodes are designed to conduct in reverse breakdown at a specific voltage, used for voltage regulation. LEDs emit light when forward biased.
齐纳二极管被设计在特定电压下发生反向击穿导通，用于电压调节。发光二极管（LED）在正向偏置时发光。
Remember: ‘Diode is a one‑way valve for electricity.’ For doping, ‘n for negative (extra electrons), p for positive (holes).’
记住：“二极管是电的单向阀。”对于掺杂，“n 是负 (negative) 表示多余电子，p 是正 (positive) 表示空穴。”
8. Transistors and Amplification | 晶体管与放大
A bipolar junction transistor (BJT) has three terminals: base, collector and emitter. A small base current controls a much larger collector current, enabling amplification. The current gain β = I_C / I_B.
双极结型晶体管（BJT）有三个端子：基极、集电极和发射极。微小的基极电流控制大得多的集电极电流，从而实现放大。电流增益 β = I_C / I_B。
Field‑effect transistors (FETs) are voltage‑controlled devices. The most common type, the MOSFET, uses a gate voltage to control the conductivity of a channel between source and drain.
场效应晶体管（FET）是电压控制器件。最常见的类型 MOSFET 利用栅极电压控制源极与漏极之间沟道的导电性。
Amplifier configurations such as common‑emitter provide voltage gain, while common‑collector (emitter follower) gives current gain with no voltage amplification.
放大电路组态如共发射极提供电压增益，而共集电极（射极跟随器）则提供电流增益，但没有电压放大作用。
Key phrase: ‘Transistor = trans‑resistor, a device that transfers resistance.’ Think of a small tap controlling a huge water main.
关键短语：“Transistor = trans‑resistor，即转换电阻的器件。”想象一个小水龙头控制着巨大的输水干管。
9. Digital Logic Gates and Boolean Algebra | 数字逻辑门与布尔代数
Basic logic gates include NOT, AND, OR, NAND, NOR, XOR and XNOR. Each is defined by a truth table showing output for all input combinations.
基本逻辑门包括 NOT、AND、OR、NAND、NOR、XOR 和 XNOR。每种门都由真值表定义，显示所有输入组合下的输出。
Boolean algebra uses variables with values 0 and 1 and operators such as AND (·), OR (+) and NOT (‾). De Morgan’s theorems are essential for simplifying logic expressions: (A·B)’ = A’ + B’ and (A+B)’ = A’·B’.
布尔代数使用值为 0 和 1 的变量，以及 AND (·)、OR (+) 和 NOT (‾) 等运算符。德摩根定理是简化逻辑表达式的关键：(A·B)′ = A′ + B′ 和 (A+B)′ = A′·B′。
Combinational logic circuits, such as adders and multiplexers, produce outputs solely from current inputs. Sequential circuits, including flip‑flops and counters, have memory of past states.
组合逻辑电路（如加法器和多路选择器）仅根据当前输入产生输出。时序逻辑电路（包括触发器和计数器）则具有对过去状态的记忆。
Mnemonics: ‘AND is both‑or‑nothing; OR is any‑one.’ For NAND and NOR, add a ‘not’ bubble at the output.
助记：“AND 是两者皆真才为真；OR 是任一为真即为真。”对于 NAND 和 NOR，在输出端加一个“非”小圆圈。
10. Statics: Forces, Moments and Equilibrium | 静力学：力、力矩与平衡
For a body to be in static equilibrium, the resultant force and the resultant moment must both be zero. These conditions are written as Σ F = 0 and Σ M = 0.
要使物体处于静力平衡，合力与合力矩都必须为零。这些条件写为 Σ F = 0 和 Σ M = 0。
A moment (or torque) is the turning effect of a force, calculated as M = F × d, where d is the perpendicular distance from the pivot to the line of action. The principle of moments states that for equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
力矩是力的转动效应，计算为 M = F × d，其中 d 是从支点到力作用线的垂直距离。力矩原理指出，平衡时顺时针力矩之和等于逆时针力矩之和。
Free‑body diagrams isolate a body, showing all external forces and moments. They are essential for solving complex structures such as trusses and frames using methods of joints or sections.
隔离体图将物体隔离，显示所有外力和外力矩。它们是使用节点法或截面法求解桁架和框架等复杂结构的必备工具。
Quick recap: ‘If it doesn’t move and doesn’t spin, ΣF=0 and ΣM=0.’ For moments, remember ‘force times perpendicular distance’.
快速回顾：“如果不动也不转，则 ΣF=0 且 ΣM=0。”对于力矩，记住“力乘以垂直距离”。
Published by TutorHao | Engineering Revision Series | aleveler.com
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