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詞或詞組	中文	英文解釋中文解釋
A-basis	A-基礎	Mechanical property value above which at least 99% of the population of values is expected to fall, with a confidence of 95%. Also called A-allowable. 機械性能值超過該值時，至少99%的值預計會下降，置信度為95%。也被稱為A-容許。
Abelian group	阿貝爾群	Property of a group of elements associated with a binary operation. In an Abelian group, the group elements commute under the binary operation. If a and b are any two group elements and if the (+) sign denotes the binary operation, then, for an Abelian group, 與二元運算相關的一組元素的屬性。在阿貝爾群中，群元素在二元運算下交換。如果a和b是任意兩個群元素并且（+）符號表示二元運算
Ablation cooling	燒蝕冷卻	The cooling of a surface exposed to very high external gas temperature which causes the surface material to sublime, melt or decompose. The chemical process absorbs heat while the mass flow of material away from the surface blocks the heat flux from the hot gas. 冷卻暴露于非常高的外部氣體溫度的表面，導致表面材料升華、熔化或分解。化學過程吸收熱量，而遠離表面的物質的質量流阻擋了來自熱氣體的熱通量。
Ablative materials	燒蝕材料	Materials, especially coating materials, designed to provide thermal protection to a body in a fluid stream through the loss of mass. 材料，尤其是涂層材料，旨在通過質量損失為流體流中的物體提供熱保護。
Abradant	研磨劑	The differently sized grits of hard materials such as emery employed for grinding, polishing, etc. The abrasive grade is determined by the grit size (grit number) originally related to the hole sizes in wire sieves. 用于研磨、拋光等的硬質材料（例如金剛砂）的不同尺寸粒度。磨料等級由最初與金屬絲篩孔尺寸相關的粒度（粒度數）決定。
Abrasion	磨損	The removal of surface material by the scratching action of hard particles, either deliberately (abrasive papers, abrasive cleaning, abrasive machining) or as a consequence of operation (wear). 通過硬質顆粒的刮擦作用去除表面材料，可以是故意的（砂紙、研磨清潔、研磨加工），也可以是操作的結果（磨損）。
Abrasive wear	磨料磨損	The removal or displacement of material from a surface when hard particles slide or roll across the surface under pressure. The particles may be loose or may be part of another surface in contact with the surface being worn. Contrast with adhesive wear. 當硬質顆粒在壓力下在表面上滑動或滾動時，材料從表面上的去除或位移。顆粒可能是松散的或可能是與被磨損表面接觸的另一個表面的一部分。與粘著磨損形成對比。
Abrasivity	磨蝕性	The extent to which a surface, particle, or collection of particles will tend to cause abrasive wear when forced against a solid surface under relative motion and under prescribed conditions. 在相對運動和規定條件下，一個表面、顆粒或顆粒集合在被迫抵靠固體表面時趨向于引起磨粒磨損的程度。
ABS polymer	ABS聚合物	A class of thermoplastic co-polymer consisting of the three monomers acrylonitrile, butadiene and styrene that has improved properties (particularly toughness) over the individual constituents. 一類由丙烯腈、丁二烯和苯乙烯三種單體組成的熱塑性共聚物，其性能（特別是韌性）優于單個成分。
Absolute expansion	絕對擴張	The true volumetric expansion of a liquid with temperature, after account is taken of any expansion of the container in which it is held. 考慮到容納液體的容器的任何膨脹后，液體隨溫度的真實體積膨脹。
Absolute humidity	絕對濕度	The weight of water vapor in a gadwater vapor mixture per unit volume of space occupied, expressed, for example, in grains or pounds per cubic foot. 單位體積空間占用的水蒸氣混合物中水蒸氣的重量，例如，以谷物或磅/立方英尺表示。
Absolute manometer	絕對壓力計	A manometer that measures absolute pressure, i.e. pressure measured relative to a perfect vacuum. Absolute pressure cannot be negative. 測量絕對壓力的壓力計，即相對于完美真空測量的壓力。絕對壓力不能為負。
Absolute pressure	絕對壓力	1. The pressure measured relative to zero pressure (vacuum). 2. Gage pressure plus barometric pressure in the same units. 1.相對于零壓力（真空）測量的壓力。2.表壓加上大氣壓力的單位相同。
Absolute rating	絕對標稱值	A theoretical size designation which is an estimation of the largest particle, by length, that can pass through a filter with a specific 一個理論尺寸名稱，它是按長度估算的最大顆粒，它可以通過具有特定過濾器的過濾器
Absolute specific gravity	絕對比重	The ratio of the weight of any volume of a substance to the weight of an equal volume of a reference substance at the same temperature, often water at 4°C, both measured in a vacuum to avoid any effect of buoyancy. 在相同溫度下，任何體積的物質的重量與等體積的參考物質的重量之比，通常是4°C的水，兩者都是在真空中測量的，以避免任何浮力的影響。
Absolute stability	絕對穩定	Condtion of a linear system in which there exists a limiting value of the open-loop gain such that the system is stable for all lower values of that gain, and unstable for all higher values. 線性系統的條件，其中存在開環增益的限制值，使得系統對于該增益的所有較低值都是穩定的，而對于所有較高值來說都是不穩定的。
Absolute temperature (Unit K)	絕對溫度（單位K）	A temperature T measured relative to absolute zero, 0 K or ?273.15°C, the lowest temperature achievable at which molecular motion vanishes so that a body would have zero heat energy. The kelvin is equal in magnitude to the degree Celsius (°C). The kelvin temperature scale (kelvin absolute temperature scale) is an absolute or thermodynamic temperature scale derived from the Celsius scale: T(K) = T(°C) + 273.15. The Rankine absolute scale is derived from the Fahrenheit scale such that T(R) = T(°F) + 459.67, i.e. a scale relative to 0 R or ?459.67°F where R is the Rankine degree symbol and °F is the Fahrenheit symbol. 相對于絕對零、0K或0K測量的溫度T?273.15°C，分子運動消失的最低溫度，因此物體的熱能為零。開爾文的大小等于攝氏度（℃）。開爾文溫度標度（開爾文絕對溫度標度）是從攝氏標度得出的絕對或熱力學溫度標度：T（K）=T（°C）+273.15。蘭金絕對標度是從華氏標度得出，使得T（R）=T（°F）+459.67，即相對于0R或0R的標度?459.67°F，其中R是朗肯度符號，°F是華氏度符號。
Absolute value error	絕對值誤差	The magnitude of the error dlsregarding the algebraic sign, or, for a vectorial error, disregarding its function. 關于代數符號的誤差幅度，或者，對于矢量誤差，不考慮其函數。
Absolute viscosity	絕對粘度	A measure of the internal shear properties of fluids, expressed as the tangential force per unit area at either of two horizontal planes separated by one unit thickness of a given fluid, one of the planes being fixed and the other moving with unit velocity. 流體內部剪切特性的量度，表示為兩個水平面中的任何一個上的單位面積切向力，兩個水平面被給定流體的一個單位厚度隔開，其中一個平面固定，另一個以單位速度移動。
Absolute zero	絕對零度	Temperature of -273.16″C or 459.69″F or OK at which molecular motion vanishes and a body has no heat energy. 溫度為-273.16″C或459.69″F，此時分子運動消失且物體沒有熱能。
Absorber	吸收器	1. An auxiliary vibratory system that favourably modifies the vibration characteristics of a main system. 2. Part of an absorption refrigeration system in which the refrigerant is absorbed by a transport medium. 3. The absorber plate is the receiver of a concentrating solar collector where the radiation is absorbed. 1.一種輔助振動系統，可有利地改變主系統的振動特性。2.吸收式制冷系統的一部分，其中制冷劑被傳輸介質吸收。3.吸收板是吸收輻射的聚光太陽能集熱器的接收器。
Absorptance	吸收率	(absorptivity, absorption coefficient, α) The fraction of radiant flux incident on a surface that is absorbed by the surface. The term also applies to absorption of radiation by a volume of fluid. For a semi-transparent surface, α + ρ + τ = 1, where ρ is the reflectance and τ is the transmittance. （吸收率，吸收系數，α）入射到表面的輻射通量被表面吸收的部分。該術語也適用于一定體積的流體對輻射的吸收。對于半透明表面，α+ρ+τ=1，其中ρ是反射率，τ是透射率。
Absorption	吸收	The process whereby a fluid permeates a porous solid, or a gas is dissolved by a liquid. 流體滲透多孔固體或氣體被液體溶解的過程。
Absorption dynamometer	吸收式測功機	A dynamometer in which input work or power is dissipated by mechanical friction, electrical resistance, hydraulic resistance, etc. 通過機械摩擦、電阻、液壓阻力等耗散輸入功或功率的測功機。
Absorption hygrometer	吸收式濕度計	An instrument that determines the content of water vapour in the atmosphere by it being absorbed into a hygroscopic medium. 通過吸收到吸濕介質中來確定大氣中水蒸氣含量的儀器。
Accelerated testing	加速測試	A type of testing, for rates of wear, fatigue, corrosion etc., in which failure times are reduced by employing greater loads, more frequent power cycling, higher vibration levels, higher humidity, higher temperatures, greater potential differences etc. than would be encountered in normal operation. 一種測試類型，用于測試磨損率、疲勞率、腐蝕率等，通過采用比正常運行中更大的負載、更頻繁的功率循環、更高的振動水平、更高濕度、更高溫度、更大的電位差等，減少故障時間。
Acceleration due to gravity	重力加速度	(acceleration of free fall, gravitational acceleration, g) (Unit m/s2) The acceleration of a freely-falling body in a vacuum, with a mean value at sea level of approximately 9.81 m/s2. （自由落體加速度，重力加速度，g）（單位m/s2）自由落體在真空中的加速度，在海平面處的平均值約為9.81m/s2。
Acceleration-error constant	加速度誤差常數	When the reference (demand) input to a control system is parabolic, the output signal will also be parabolic in steady state. The signal that is constant in this situation is the acceleration and thus for a parabolic input the steady-state error, referred to as the acceleration-error constant, is the error in the acceleration. 當控制系統的參考（需求）輸入是拋物線時，輸出信號在穩定狀態下也將是拋物線。在這種情況下恒定的信號是加速度，因此對于拋物線輸入，稱為加速度誤差常數的穩態誤差是加速度中的誤差。
Accommodation	適應能力	The ability of a robot to respond to changes in the environment. 機器人對環境變化做出反應的能力。
Achme thread	Achme螺紋	A screw thread having an included angle of 29° and largely used for feed screws on machine tools. 一種夾角為29°的螺紋，主要用于機床上的進給絲杠。
Acicular ferrite	針狀鐵素體	A highly substructured non-equiaxed ferrite that forms upon continuous cooling by a mixed diffusion and shear mode of transformation that begins at a temperature slightly higher than the temperature transformation range for upper bainite. It is distinguished from bainite in that it has a limited amount of carbon available; thus, there is only a small amount of carbide present. Ferrite crystallite growing, apparently, as in the course of bainitic transformation. It has a lath-like shape and an increased dislocation 一種高度亞結構的非等軸鐵素體，在連續冷卻時通過混合擴散和剪切相變模式形成，其開始溫度略高于上貝氏體的溫度轉變范圍。它與貝氏體的區別在于它的碳含量有限。因此，僅存在少量碳化物。顯然，鐵素體微晶在貝氏體轉變過程中生長。它具有板條狀的形狀和增加的位錯。
Acid rain	酸雨	Any form of precipitation, including rain, snow, sleet, fog, dew, and particulates, which contains higher than normal levels of sulfuric and nitric acids. These acids result from natural and man-made emissions of sulfur dioxide and oxides of nitrogen, respectively. Acid soot consists of unburned carbon particles, typically larger than 10 μm, in the atmosphere contaminated with sulfuric acid. The particles result from poor combustion of fossil fuels. 任何形式的降水，包括雨、雪、雨夾雪、霧、露水和顆粒物，其中含有高于正常水平的硫酸和硝酸。這些酸分別來自二氧化硫和氮氧化物的自然排放和人為排放。酸煙灰由未燃燒的碳顆粒組成，通常大于10微米，在被硫酸污染的大氣中。這些顆粒是化石燃料燃燒不良造成的。
Ackerman linkage	阿克曼裝置	A steering linkage on a motor vehicle that approximately gives rolling without slipping of both wheels about the turning point. This is achieved by having the inner stub axle (on the inside of the turning curve) move through a greater angle than the outer stub axle. 機動車輛上的一種轉向聯動裝置，在轉向點附近兩個車輪幾乎不會打滑。這是通過使內短軸（在轉彎曲線的內側）比外短軸移動更大的角度來實現的。
Acoustic droplet ejection	聲液滴噴射	The ejection of small droplets from the surface of a liquid that results from focusing high-intensity ultrasound near the surface. 由于在表面附近聚焦高強度超聲波而從液體表面噴射出小液滴。
Acoustic emission	聲發射	(stress-wave emission) Sound emitted by some materials when deformed under load. It arises from stress waves emitted by sudden dislocation motion in crystals, slip, crack growth, etc. （應力波發射）某些材料在負載下變形時發出的聲音。它是由晶體中突然的位錯運動、滑移、裂紋擴展等發出的應力波引起的。
Acoustic power	聲功率	(sound power) (Unit W) The rate of flow of acoustic energy across a specified surface. （聲功率）（單位W）聲能流過指定表面的速率。
Acoustic pyrometer	聲學高溫計	A non-intrusive pyrometer based on the principle that the sound speed in a gas is proportional to the square root of its absolute temperature. 一種非侵入式高溫計，其原理是氣體中的聲速與其絕對溫度的平方根成正比。
Acoustic separation	聲學分離	?(Unit m) The separation of particles in a fluid using standing acoustic waves, typically ultrasound, to drive them to nodal points (acoustic particle concentration). （單位m）使用駐聲波（通常是超聲波）將流體中的粒子分離，以將它們驅動到節點（聲學粒子濃度）。
Acoustics	聲學	The science and engineering of sound; its production, propagation, control, interaction with materials, etc. 聲音科學與工程；它的產生、傳播、控制、與材料的相互作用等。
Activation energy	活化能	(Ea, U) (Unit kJ/mol) The minimum energy for a chemical reaction to occur or for processes such as diffusion to take place in crystals. （Ea, U）（單位kJ/mol）發生化學反應或在晶體中發生擴散等過程的最小能量。
Active accommodation	主動適應能力	The use of information from sensors, for example, in a vision system, that allows a robot to show accommodation to the environment. 使用來自傳感器的信息，例如在視覺系統中，允許機器人顯示對環境的適應。
Active vibration suppression	主動振動抑制	The reduction of undesirable vibration in components by feedback control. 通過反饋控制減少部件中的不良振動。
Actual cubic feet per minute	實際立方英尺每分鐘	(acfm) An obsolete (i.e. non-SI) measure of volumetric flow rate; the volume of a gas flowing per minute at actual operating pressure and temperature, as opposed to the corresponding volume flow rate at STP. （acfm）已被淘汰的（即非SI）體積流量測量；在實際工作壓力和溫度下每分鐘流動的氣體體積，與STP下的相應體積流量相反。
Actual power	實際功率	(actual horsepower) (Unit W or hp) The power delivered at the output shaft of an engine, before subsequent transmission through a gearbox etc. （實際馬力）（單位W或hp）在隨后通過變速箱等傳輸之前，在發動機輸出軸上傳遞的功率。
Actual value	實際價值	The output of a plant that is being controlled, i.e. the controlled variable. Not directly accessible by the control system, as it can only be measured by a sensor which may distort the measurement. 受控設備的輸出，即受控變量。控制系統不能直接訪問，因為它只能由可能會扭曲測量結果的傳感器測量。
Actuating system	驅動系統	A system in which an electrical, pneumatic or hydraulic input supplied to an actuator produces force, torque, or displacement, usually in a controlled way. 一種系統，其中提供給執行器的電氣、氣動或液壓輸入通常以受控方式產生力、扭矩或位移。
Adhesive joint	粘合接頭	The point or area in which two structures are held together by an adhesive. 兩個結構通過粘合劑粘合在一起的點或區域。
Adhesive strength	粘合強度	The strength of an adhesively bonded joint, usually measured in tension (perpendicular to the plane of the bonded joint) or in shear 粘合接頭的強度，通常以拉伸（垂直于粘合接頭的平面）或剪切測量
Adhesive wear	粘著磨損	Wear that develops when two surfaces slide across one another under pressure. The removal or displacement of material from a surface by the welding together and subsequent shearing of minute areas of two surfaces that slide across each other under pressure. In advanced stages, may lead to galling. Contrast with abrasive wear. 當兩個表面在壓力下相互滑動時產生的磨損。通過焊接在一起并隨后剪切在壓力下相互滑動的兩個表面的微小區域，從表面去除或置換材料。在晚期，可能會導致擦傷。與磨料磨損形成對比。
Aerated bath nitriding	空氣攪拌液體滲氮法	A type of liquid nitriding in which air is pumped through the molten bath creating agitation and increased chemical activity. 一種液體氮化，其中空氣被泵入熔池，產生攪拌并增加化學活性。
Age hardening	時效硬化	Raising the strength and hardness of an alloy by heating a supersaturated solid solution at a relatively low temperature to induce precipitation of a finely dispersed second phase. Also known as aging or precipitation hardening. Hardening by aging, usually after rapid cooling or cold working. 通過在相對較低的溫度下加熱過飽和固溶體以誘導細分散的第二相沉淀來提高合金的強度和硬度。也稱為時效或沉淀硬化。通常在快速冷卻或冷加工后。
Age softening	時效軟化	Spontaneous decrease of strength and hardness that takes place at room temperature in certain strain hardened alloys, especially those of aluminum. 某些應變硬化合金，尤其是鋁合金，在室溫下會發生強度和硬度的自發降低。
Aging treatment	時效處理	Heat treatment aimed at age hardening; it comprises solution and precipitation treatments. 針對時效硬化的熱處理；它包括溶液和沉淀處理。
Air classifier	空氣分級機	(air elutriator) A device in which an airstream, which may be swirling, sorts particles by a combination of size, shape, and mass. （空氣淘析器）一種裝置，在該裝置中，氣流（可能是漩渦）根據大小、形狀和質量的組合對顆粒進行分類。
Air cleaner	空氣凈化器	A device, such as a filter, hydrocyclone, or electrostatic precipitator, that removes particles and aerosols from a flow of air. 一種設備，例如過濾器、水力旋流器或靜電除塵器，用于從氣流中去除顆粒和氣溶膠。
Air composition	空氣成分	The sea-level composition (in per cent by volume) of air at a temperature of 15°C and a pressure of 1 atm is mainly 78.084% nitrogen, 20.947% oxygen and 0.934% argon. The remaining 0.035% consists of carbon dioxide, neon, helium, methane, krypton, hydrogen, oxides of nitrogen, xenon, ozone, iodine, carbon monoxide, and ammonia. Different sources give slightly different figures for the composition. Not included are water vapour (typically 0.4%) and pollutants such as sulfur dioxide. 在15°C的溫度和1個大氣壓的壓力下，空氣的海平面成分（體積百分比）主要是78.084%的氮氣、20.947%的氧氣和0.934%的氬氣。剩余的0.035%由二氧化碳、氖、氦、甲烷、氪、氫、氮的氧化物、氙、臭氧、碘、一氧化碳和氨組成。不同的來源給出的組成略有不同。不包括水蒸氣（通常為0.4%）和二氧化硫等污染物。
Air compressor	空氣壓縮機	A turbomachine that draws in air and delivers it at higher pressure, temperature, and density. It can be of axial, fan, reciprocating, or rotary design. 一種渦輪機，它吸入空氣并以更高的壓力、溫度和密度輸送空氣。它可以是軸流式、風扇式、往復式或旋轉式設計。
Air conditioning	空調	The process of controlling the temperature and humidity in rooms, buildings, aircraft, passenger vehicles, etc. More generally it includes control of dust, levels of radiant heat, etc. 控制房間、建筑物、飛機、客運車輛等的溫度和濕度的過程。更一般地說，它包括控制灰塵、輻射熱水平等。
Air pump	氣泵	A machine for providing a flow of air or for increasing or decreasing the mass and pressure of air in a closed container. The term pump is more usual when the working fluid is a liquid, while compressor is more usual for gases. 一種用于提供空氣流動或用于增加或減少密閉容器中空氣質量和壓力的機器。當工作流體是液體時，術語泵更常用，而氣體更常用壓縮機。
Air-cooled condenser	風冷冷凝器	A heat exchanger, in which the cooling medium is air, used to condense the exhaust steam from a steam turbine, the condensate being returned to the boiler. 一種熱交換器，其中冷卻介質為空氣，用于冷凝蒸汽輪機排出的蒸汽，冷凝水返回鍋爐。
Air-cooled engine	風冷發動機	An internal-combustion engine directly cooled by airflow, rather than by water flowing through the engine block being cooled by a radiator. 一種由氣流直接冷卻的內燃機，而不是通過流經發動機缸體的水被散熱器冷卻。
Air-hardening steel	空氣硬化鋼	A steel containing sufficient carbon and other alloying elements to harden fully during cooling in air or other gaseous mediums from a temperature above its transformation range. The terms should be restricted to steels that are capable of being hardened by cooling in air in fairly large sections, about 2 in. (50 mm) or more in diameter. Same as self-hardening steel. 一種鋼，含有足夠的碳和其他合金元素，可以在空氣或其他氣體介質中從高于其轉變范圍的溫度冷卻過程中完全硬化。這些術語應僅限于能夠通過在相當大的截面（直徑約2英寸（50毫米）或更大）中通過空氣冷卻而硬化的鋼。與自硬鋼相同。
AISC	AISC	The American Institute of Steel Construction. 美國鋼結構學會。
Allotropy	同素異形體	A near synonym for polymorphism. Allotropy is generally restricted to describing polymorphic behavior in elements, terminal phases, and alloys whose behavior closely parallels that of the predominant constituent element. 多態性的近義詞。同素異形體通常僅限于描述元素、終端相和合金中的多晶型行為，其行為與主要組成元素的行為非常相似。
Allowable stress	許用應力	The maximum stress a designer can assume that the parts will stand. It is always less than the minimum strength of the material. For example, the ASME Boiler and Pressure Vessel Code typically specifies an allowable stress that is one-quarter of the service temperature yield strength of the material. This introduces a four-to-one safety factor into the design process and is intended to compensate for uncertainties in estimates of strength, service loads, etc. 設計師可以假設零件能夠承受的最大應力。它總是小于材料的最小強度。例如，ASME鍋爐和壓力容器規范通常指定允許應力為材料使用溫度屈服強度的四分之一。這在設計過程中引入了四比一的安全系數，旨在補償強度、服務載荷等估計的不確定性。
Allowable stress design	許用應力設計	A design procedure developed for the AISC by the Research Council on Structural Connections. Purposely underestimates the strengths of bolts and joint materials to introduce safety factors into the design of structural steel joints. It is an alternative to the more recently defined load and resistance factor design procedure. 結構連接研究委員會為AISC制定的設計程序。故意低估螺栓和接頭材料的強度，以便在結構鋼接頭的設計中引入安全系數。它是最近定義的荷載和阻力系數設計程序的替代方法。
Alloy	合金	1. A metallic material composed of two or more elements, one of which is usually a metal to which the other elements are added, e.g. iron-carbon or aluminium-copper (binary alloy); nickel-chromium-iron (ternary alloy). 2. A plastic produced as a blend of two or more immiscible polymers. This results in material that cannot be achieved by polymerization. 1.由兩種或多種元素組成的金屬材料，其中一種通常是添加了其他元素的金屬，例如鐵碳或鋁銅（二元合金）；鎳鉻鐵（三元合金）。2.由兩種或多種不混溶聚合物混合而成的塑料。這導致無法通過聚合獲得的材料。
Alloy steels	合金鋼	Steels that contain alloying elements such as chromium, nickel, molybdenum, manganese, silicon, tungsten, and vanadium. These are added to improve properties such as the hardenability, toughness, strength, wear resistance, and corrosion resistance compared with those of plain-carbon steel. Low-alloy steels have a total alloy content (including carbon) of less than about 8%. They are hardenable and have strength up to 30% higher than plain-carbon steels. High-alloy steels contain considerably more alloy content and are developed for specific properties such as superior corrosion and chemical resistance. 含有鉻、鎳、鉬、錳、硅、鎢和釩等合金元素的鋼。添加這些是為了提高與普通碳鋼相比的淬透性、韌性、強度、耐磨性和耐腐蝕性等性能。低合金鋼的總合金含量（包括碳）小于約8%。它們是可硬化的，強度比普通碳鋼高出30%。高合金鋼含有相當多的合金含量，并針對特定性能而開發，例如卓越的耐腐蝕性和耐化學性。
Alloying element	合金元素	Component added deliberately with the aim of improving the properties of an alloy. Alloying elements can affect the existence range of equilibrium phases present in an unalloyed material, or lead to the occurrence of new phases, or both. In addition, alloying elements strongly affect the kinetics of phase transformations and thus the microstructure formation in alloyed materials. 為改善合金性能而有意添加的成分。合金元素可以影響非合金材料中存在的平衡相的存在范圍，或導致新相的出現，或兩者兼而有之。此外，合金元素強烈影響相變動力學，從而影響合金材料的微觀結構形成。
Alpha iron	阿爾法鐵	The body-centered cubic form of pure iron, stable below 910 °C (1670 °F). 純鐵的體心立方形式，在910°C(1670°F)以下穩定。
Alternating stress	交替應力	?(Unit Pa) Originally, stresses of changing sign (tension-tocompression-to-tension, etc.) in a component produced by alternating forces acting in opposite directions, but now generally used to describe stresses that vary but may keep the same sign, as produced by periodic, out-of–balance, or vibrational loads. （單位Pa）最初，構件中由相反方向的交變力產生的符號變化的應力（張力到壓縮到張力等），但現在通常用于描述變化但可能保持相同符號的應力，如由周期性、失衡或振動載荷產生的應力。
Alternative energy	可替代能源	(alternate energy) Energy sources that are renewable and do not have the undesired consequences of fossil fuels and nuclear energy. （替代能源）可再生能源，不會產生化石燃料和核能的不良后果。
Altitude	高度	(Unit m) Vertical height measured relative to a specified datum such as sea level. （單位m）相對于特定基準（例如海平面）測量的垂直高度。
Altitude chamber	高空艙	(hypobaric chamber) A chamber in which conditions at different altitudes are simulated by a combination of appropriate pressures, temperatures and relative humidity. （低壓艙）通過適當的壓力、溫度和相對濕度的組合來模擬不同高度條件的艙室。
Amontons friction	阿蒙頓摩擦	(Coulomb friction) Friction between surfaces where the ratio of the frictional force F to the normal force N is constant and independent of the area in contact. （庫侖摩擦）摩擦力F與法向力N之比恒定且與接觸面積無關的表面之間的摩擦。
Amplifier	放大器	A device by which the output of a hydraulic, pneumatic, or electrical source is increased. 增加液壓、氣動或電源輸出的裝置。
Anelastic	無彈性	Literally ‘not elastic’, but in practice used for materials that display timedependent recovery on unloading. 字面意思是“沒有彈性”，但實際上用于在卸載時顯示隨時間恢復的材料。
Angle of attack (α)	攻角（α）	(Unit °) The angle between a reference line on a lifting body and the vector direction of the relative velocity between the body and the fluid through which it is moving. In the case of an aerofoil, turbine, or compressor blade, the usual reference line is the chord line. （單位°）升力體上的參考線與升力體與其運動通過的流體之間的相對速度的矢量方向之間的角度。在機翼、渦輪或壓縮機葉片的情況下，通常的參考線是弦線。
Angle of contact	接觸角	(Unit °) The angle subtended at the centre of a pulley or sprocket wheel by the circumferential contact of a belt or chain. （單位°）皮帶或鏈條的圓周接觸在皮帶輪或鏈輪的中心所對的角度。
Angle of friction	摩擦角	(friction angle, β) (Unit °) For a body in contact with a plane surface, the angle between the normal to the surface and the resultant force between the body and the surface. If the friction force is F and normal force is N, β is given by F/N = μ = tan β where μ is the coefficient of friction. （摩擦角，β）（單位°）對于與平面接觸的物體，表面法線與物體與表面之間的合力之間的夾角。如果摩擦力為F，法向力為N，則β由F/N=μ=tanβ給出，其中μ是摩擦系數。
Angle of thread	螺紋角度	The included angle between the sides forming the groove of the screw thread. 形成螺紋凹槽的邊之間的夾角。
Angle of torsion	扭轉角	(angle of twist) (Unit ° or rad) The angle relative to a chosen section, normal to the axis of twist, through which another part of a component rotates when subjected to a torque. （扭轉角）（單位°或弧度）相對于選定截面的角度，垂直于扭轉軸，部件的另一部分在受到扭矩時通過該角度旋轉。
Angstr?m (?)	昂斯特羅姆（?）	An obsolete (non-SI) unit of length, sometimes still employed for atomic and crystallographic measurements. The conversion to SI is 1 ? = 10?10?m. 一種已被淘汰的（非SI）長度單位，有時仍用于原子和晶體學測量。轉換為SI為1?=10-10m。
Angularity	角度	The underfaces of the nut and the bolt head should be exactly perpendicular to the thread or shank axes. If the angle between the face and the axis is, for example, 868 or 948, the fastener is said to have an angularity of 48 (sometimes called Perpendicularity). 螺母和螺栓頭的底面應與螺紋或柄軸完全垂直。例如，如果面和軸之間的角度為868或948，則稱緊固件的角度為48（有時稱為垂直度）。
Anisotropy	各向異性	The characteristic of exhibiting different values of a property in different directions with respect to a fixed reference system in the material. 相對于材料中的固定參考系統，在不同方向上表現出不同屬性值的特性。
Anneal to temper	退火回火	A final partial anneal that softens a cold worked nonferrous alloy to a specified level of hardness or tensile strength. 將冷加工的有色金屬合金軟化到規定的硬度或抗拉強度水平的最終局部退火。
Annealing	退火	A generic term denoting a treatment, consisting of heating to and holding at a suitable temperature followed by cooling at a suitable rate, used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. 一個通用術語，表示一種處理，包括加熱并保持在合適的溫度，然后以合適的速率冷卻，主要用于軟化金屬材料，但也同時產生其他性能或微觀結構的所需變化。
Annealing carbon	退火碳	Fine, apparently amorphous carbon particles formed in white cast iron and certain steels during prolonged annealing. Also called temper carbon. 白口鑄鐵和某些鋼在長時間退火過程中形成的細小、明顯的無定形碳顆粒。也稱為回火碳。
Annealing twin	退火孿晶	A twin form in a crystal during recrystallization. 重結晶過程中晶體中的孿晶形式。
Anode	陽極	That electrode in a battery or corrosion cell which produces electrons. It is the electrode which is destroyed (corrodes). 電池或腐蝕電池中產生電子的電極。被破壞（腐蝕）的是電極。
ANSI	ANSI	The acronym for American National Standards Institute. 美國國家標準協會的縮寫。
Anti-freeze	防凍液	A substance such as ethylene glycol added to the cooling system of a watercooled engine to lower the freezing point of the cooling water and also inhibit the formation of rust and other deposits. 一種物質，如乙二醇，添加到水冷發動機的冷卻系統中，以降低冷卻水的冰點，并抑制生銹和其他沉積物的形成。
Apparent area of contact	表觀接觸面積	In tribology, the area of contact between two solid surfaces defined by the boundaries of their macroscopic interface. 在摩擦學中，兩個固體表面之間的接觸區域由其宏觀界面的邊界定義。
Applied thermodynamics	應用熱力學	(engineering thermodynamics, thermodynamics) The science of the relationship between heat, work and the properties of systems and the ways in which heat energy from fuels can be converted into mechanical work. It involves the study of all aspects of energy use and energy transformation, including power generation, refrigeration, the relevant properties of the substances involved and the relationships between them. The principle of conservation of energy is a fundamental law of nature. （工程熱力學、熱力學）熱、功和系統特性之間關系的科學，以及燃料中的熱能可以轉化為機械功的方式。它涉及能源使用和能源轉換的各個方面的研究，包括發電、制冷、所涉及物質的相關特性以及它們之間的關系。能量守恒定律是自然的基本規律。
Arbitration bar	抗彎試棒	A test bar, cast with a heat of material, used to determine chemical composition, hardness, tensile strength, and deflection and strength under transverse loading in order to establish the state of acceptability of the casting. 用熱材料鑄造的測試棒，用于確定化學成分、硬度、抗拉強度、橫向載荷下的撓度和強度，以確定鑄件的可接受狀態。
Archimedes screw	阿基米德螺旋泵	A machine which comprises a rotating helical blade inside a closefitting tube, which may be used to pump liquids, slurries (such as sewage), granular materials, etc. If water flows into the top of an inclined or vertical Archimedes screw, the screw will rotate and can be used to drive an electrical generator. 一種機器，它在緊密的管子內包含一個旋轉的螺旋葉片，可用于泵送液體、泥漿（如污水）、顆粒材料等。如果水流入傾斜或垂直的阿基米德螺桿的頂部，螺桿將旋轉，可用于驅動發電機。
Archimedes Wave Swing	阿基米德波擺動	A machine for tidal-power energy generation consisting of two concentric, air-filled submerged cylinders. The inner lower cylinder is tethered to the ocean floor while the upper floater unit, which is closed at the top, moves up and down due to the variations in hydrostatic pressure caused by the wave motion. The relative movement of the two cylinders is used to generate electricity in which linear motion replaces the more common rotary motion of an electromagnetic generator. 一種用于潮汐能發電的機器，由兩個同心的充氣水下氣缸組成。內部下部圓柱體系在海底，而頂部封閉的上部浮子單元由于波浪運動引起的靜水壓力變化而上下移動。兩個氣缸的相對運動用于發電，其中直線運動取代了電磁發電機更常見的旋轉運動。
Artificial aging	人工時效	Aging above room temperature. 在室溫以上的時效。
ASME	ASME	The American Society of Mechanical Engineers. 美國機械工程師學會。
Aspect ratio	縱橫比	The ratio of the longest to the shortest dimension of a shape or object e.g. the chord-to-thickness ratio of an aerofoil or the span-to-chord ratio of a wing. 形狀或物體的最長與最短尺寸之比，例如機翼的弦厚比或機翼的翼展弦比。
Assembly drawing	裝配圖紙	An engineering drawing that shows how parts are assembled to produce a component or a complete machine. It may include sections to show internal features, dimensions that are critical for assembly, manufacturing information, and part numbers. 顯示零件如何組裝以生產組件或整機的工程圖。它可能包括顯示內部特征、對裝配至關重要的尺寸、制造信息和零件編號的部分。
Assembly line	流水線	A system of mass production in which work is moved progressively from one operation to another, ultimately to give the final complete product. 一種大規模生產系統，其中工作逐漸從一個操作轉移到另一個操作，最終得到完整產品。
Athermal transformation	非熱變化	A reaction that proceeds without benefit of thermal fluctuations; that is, thermal activation is not required. In contrast, a reaction that occurs at constant temperature is an isothermal transformation; thermal activation is necessary in this case and the reaction proceeds as a function of time. 在沒有熱波動的情況下進行的反應；也就是說，不需要熱激活。相反，在恒溫下發生的反應是等溫轉變。在這種情況下，熱活化是必要的，并且反應作為時間的函數進行。
Atmometer	氣壓計	(atmidometer, evaporimeter) An instrument that measures the rate of evaporation of water from a surface into the atmosphere. （濕度計，蒸發計）測量水從表面蒸發到大氣中的速率的儀器。
Atmosphere	大氣	1. (atm) An obsolete (non-SI) unit of pressure equal to 101 325 Pa or 1.013 25 bar and approximately equal to the atmospheric pressure (barometric pressure) measured at mean sea level. 1.（atm）一種已被淘汰的（非SI）壓力單位，等于101325Pa或1.01325bar，大約等于在平均海平面測量的大氣壓力（大氣壓）。
Atmospheric pressure	氣壓	The downward force exerted by the atmosphere because of its weight, (gravitational attraction to the Earth), measured by barometers, and usually expressed in units of millibars. Standard atmospheric pressure at sea level is 1013.25 mb.expressed in units of millibars. Standard atmospheric pressure at sea level is 1013.25 mb. 大氣由于其重量（對地球的引力）而施加的向下的力，用氣壓計測量，通常以毫巴為單位表示。海平面的標準大氣壓為1013.25mb。以毫巴為單位表示。海平面的標準大氣壓為1013.25mb。
Atom	原子	The smallest unit of matter that has the properties of a chemical element. The simplest description of an atom (Bohr model) is of a compact nucleus surrounded by one or more orbiting electrons. 具有化學元素性質的最小物質單位。原子的最簡單描述（玻爾模型）是由一個或多個軌道電子包圍的致密原子核。
Atomic volume	原子體積	Volume of unit cell per atom. 每個原子的晶胞體積。
Atomization	霧化	The production of a spray of fine droplets from a liquid, such as diesel oil or petrol, by injection through a nozzle (an atomizer). 通過噴嘴（霧化器）噴射從液體（例如柴油或汽油）中產生細小液滴噴霧。
Atomizing humidifier	霧化加濕器	A humidifier that functions by spraying fine droplets of water into an airstream. 一種加濕器，通過將細小的水滴噴射到氣流中來發揮作用。
Ausforming	形變熱處理	Thermomechanical treatment of steel in the metastable austenitic condition below the recrystallization temperature followed by quenching to obtain martensite and/or bainite. 在低于再結晶溫度的亞穩態奧氏體條件下對鋼進行熱機械處理，然后淬火以獲得馬氏體和/或貝氏體。
Austempered steels	等溫鋼	Medium to high carbon steels with improved mechanical properties as a result of austempering. After heating to between 800° and 900°C to form the austenite phase, they are quenched to, and held at, just above the martensite transformation range (between 260° and 370°C) to form bainite, before cooling further. Austempering of ductile cast irons results in a microstructure of bainite and spheroidal graphite. Austempered ductile irons have excellent toughness and wear properties. 由于等溫淬火，機械性能得到改善的中高碳鋼。在加熱到800°和900°C之間形成奧氏體相后，將它們淬火并保持在略高于馬氏體轉變范圍（260°和370°C之間）以形成貝氏體，然后進一步冷卻。球墨鑄鐵的等溫淬火導致貝氏體和球狀石墨的微觀結構。等溫淬火球墨鑄鐵具有優異的韌性和耐磨性。
Austempering	等溫淬火	A heat treatment for ferrous alloys in which a part is quenched from the austenitizing temperature at a rate fast enough to avoid formation of ferrite or pearlite and then held at a temperature just above Ms until transformation to bainite is complete. Although designated as bainite in both austempered steel and austempered ductile iron (ADI), austempered steel consists of two phase mixtures containing ferrite and carbide, while austempered ductile iron consists of two phase mixtures containing ferrite and austenite. Heat treatment comprising austenitization of a steel article, cooling it to a bainitic range at a rate higher than the critical cooling rate and holding at a fixed temperature until the completion of bainitic transformation. 一種鐵合金的熱處理，其中零件從奧氏體化溫度以足夠快的速度淬火，以避免形成鐵素體或珠光體，然后保持在略高于Ms的溫度，直到完全轉變為貝氏體。雖然在奧氏體鋼和奧氏體球鐵(ADI)中都被指定為貝氏體，但奧氏體鋼由含有鐵素體和碳化物的兩相混合物組成，而奧氏體球墨鑄鐵由含有鐵素體和奧氏體的兩相混合物組成。熱處理包括鋼制品的奧氏體化，以高于臨界冷卻速率的速率將其冷卻到貝氏體范圍，并保持在固定溫度直到貝氏體轉變完成。
Austenite	奧氏體	A solid solution of one or more elements in face-centered cubic iron. Unless otherwise designated (such as nickel austenite), the solute is generally assumed to be carbon. Solid solution of alloying elements and/or carbon in γ-Fe. It is named after British metallurgist W. C. Roberts-Austen. 一種或多種元素在面心立方鐵中的固溶體。除非另有說明（如鎳奧氏體），溶質通常假定為碳。合金元素和/或碳在γ-Fe中的固溶體。它以英國冶金學家WCRoberts-Austen的名字命名。
Austenite finish temperature (Af)	奧氏體完成溫度（Af）	Temperature at which the transformation of martensite into austenite completes upon heating. The same designation is also applied to nonferrous alloys in which martensite transforms into some parent phase. 加熱時馬氏體轉變為奧氏體的溫度。相同的名稱也適用于馬氏體轉變為某些母相的有色合金。
Austenite stabilization	奧氏體穩定化	Decrease, in comparison to a continuous cooling, in the amount of martensite occurring from austenite when cooling is interrupted at a temperature between Ms?and Mf. This can be explained by the relaxation of stresses induced in the austenite by martensite crystals occurring before the interruption. The relaxation, in turn, leads to the dislocation rearrangement and their interaction with martensite/austenite interfaces, which makes the interfaces immobile. 與連續冷卻相比，當在Ms和Mf之間的溫度中斷冷卻時，從奧氏體中產生的馬氏體的量減少。這可以通過中斷前發生的馬氏體晶體在奧氏體中引起的應力松弛來解釋。反過來，松弛導致位錯重排及其與馬氏體/奧氏體界面的相互作用，這使得界面無法移動。
Austenite-stabilizer	奧氏體穩定劑	Alloying element expanding the γ-phase field in the corresponding phase diagram, which manifests itself in a decrease of the A3?temperature and an increase of the A4?temperature in binary alloys Fe–M as well as in a decrease of A1?temperature in ternary alloys Fe–C–M (M is an alloying element). The solubility of austenite-stabilizers in ferrite is much lower than in austenite. Under the influence of austenite-stabilizers, austenite can become thermodynamically stable down to room temperature. 合金元素擴展了相應相圖中的γ相場，這表現為二元合金Fe-M中A3溫度的降低和A4溫度的升高，以及A1溫度的降低三元合金Fe–C–M（M是合金元素）。奧氏體穩定劑在鐵素體中的溶解度遠低于在奧氏體中的溶解度。在奧氏體穩定劑的影響下，奧氏體可以在低至室溫時變得熱力學穩定。
Austenitic grain size	奧氏體晶粒尺寸	The size attained by the grains of steel when heated to the austenitic region; may be revealed by appropriate etching of cross sections after cooling to room temperature. 當加熱到奧氏體區域時鋼晶粒達到的尺寸；冷卻至室溫后，可通過適當蝕刻橫截面來顯示。
Austenitic stainless steels	奧氏體不銹鋼	Austenitic stainless steels are non-magnetic. They contain significant additions of chromium (16–30%), but have the austenite (FCC) crystal structure, stabilized by the addition of nickel in the composition range 6–20%. Carbon content ranges from about 0.03 to 0.15%. The ‘18–8’ stainless steels containing approximately 18% chromium and 8% nickel are typical of the class. Austenitic stainless steels have high strength and corrosion resistance even at elevated temperatures, good ductility, good low-temperature properties, and good weldability. Used for aircraft and transport equipment, cutlery, chemical and food-processing equipment, surgical instruments, and cryogenic vessels. 奧氏體不銹鋼是非磁性的。它們含有顯著添加的鉻（16–30%），但具有奧氏體（FCC）晶體結構，通過在6–20%的成分范圍內添加鎳來穩定。碳含量范圍約為0.03至0.15%。含有大約18%鉻和8%鎳的“18-8”不銹鋼是該級別的典型不銹鋼。奧氏體不銹鋼即使在高溫下也具有高強度和耐腐蝕性，良好的延展性，良好的低溫性能和良好的焊接性。用于飛機和運輸設備、餐具、化學和食品加工設備、手術器械和低溫容器。
Austenitizing	奧氏體化	Forming austenite by heating a ferrous alloy into the transformation range (partial austenitizing) or above the transformation range (complete austenitizing). When used without qualification, the term implies complete austenitizing. 通過將鐵合金加熱到轉變范圍（部分奧氏體化）或高于轉變范圍（完全奧氏體化）來形成奧氏體。當不加限定地使用時，該術語意味著完全奧氏體化。
Autonomous energy system	自主能源系統	(stand-alone energy system) A sole source of electricity, usually small-scale, for applications remote from a grid, especially with energy storage in the system. Hydroelectric, photovoltaic, wind-power and other renewable systems are well suited to stand-alone applications. （獨立能源系統）一種唯一的電力來源，通常是小規模的，用于遠離電網的應用，尤其是系統中的能量存儲。水電、光伏、風力和其他可再生能源系統非常適合獨立應用。
Auxetic materials	拉脹材料	Those man-made materials for which Poisson’s ratio is negative, so that the cross section expands when subjected to a longitudinal tensile stress and contracts when subjected to a longitudinal compressive stress. 泊松比為負的人造材料，其橫截面在受到縱向拉應力時會膨脹，在受到縱向壓應力時會收縮。
Auxiliary power unit (APU)	輔助動力裝置（APU）	In aircraft–gas–turbine applications, a small gas turbine used to provide start-up power, electrical and hydraulic power, and compressed air for cabin ventilation. In other applications, an APU may be a gas turbine or internal-combustion engine used to provide emergency power. 在飛機-燃氣輪機應用中，小型燃氣輪機用于提供啟動動力、電力和液壓動力以及用于機艙通風的壓縮空氣。在其他應用中，APU可以是用于提供應急動力的燃氣輪機或內燃機。
Available draught (Unit Pa)	可用通風量（單位Pa）	The reduced pressure of combustion gases in a furnace or boiler, either forced or due to the buoyancy of hot gases, which is used to draw in combustion air and remove products of combustion. 爐子或鍋爐中燃燒氣體的壓力降低，無論是強制還是由于熱氣體的浮力，用于吸入燃燒空氣并去除燃燒產物。
Available head (Unit m)	可用水頭（單位米）	In a hydroelectric power system, the difference between the vertical height of the water level in the supply reservoir above the turbine inlet less the head loss due to friction and fittings in the duct leading to the turbine. 在水力發電系統中，水輪機入口上方供水水庫中水位垂直高度之間的差減去由于通向渦輪機的管道中的摩擦和配件造成的水頭損失。
Available resource	可用資源	(total resource) (Unit J) The total annual energy theoretically available from a renewable-energy source, such as ocean waves, the wind, or the total incident solar energy. （總資源）（單位J）理論上可從可再生能源（例如海浪、風或總入射太陽能）獲得的年度總能量。
Avogadro constant	阿伏伽德羅常數	(Avogadro number, NA) A fundamental physical constant with the fixed numerical value 6.022 140 76 × 1023 mol?1. The mole contains exactly this number of elementary entities. A minor adjustment to the value of the Avogadro constant was made effective on 20 May 2019. （阿伏伽德羅數，NA）一個固定數值為6.02214076×1023mol的基本物理常數?摩爾正好包含這個數量的基本實體。對阿伏伽德羅常數值的微小調整于2019年5月20日生效。
Axial load (Unit N)	軸向載荷（單位N）	In general, a tensile or compressive load directed along the axis of a component. Strictly the load should pass through the centroid of the cross section to avoid inducing bending moments and be perpendicular to the plane of the section. 通常，沿部件的軸定向的拉伸或壓縮載荷。嚴格來說，載荷應通過橫截面的質心以避免產生彎矩并垂直于橫截面。