| 詞或詞組 | 中文 | 英文解釋中文解釋 |
|---|---|---|
| Nano machining | 納米加工 |
The machining of silicon chips typically less than 1 nm thick. 硅芯片的加工通常小于1nm厚。 |
| Nanomanufacturing | 納米制造 |
1. The manufacture of nanoscale materials. 2. The manufacture of components or devices that have critical dimensions of order 1 nm. 1.納米材料的制造。2.具有1nm級臨界尺寸的部件或裝置的制造。 |
| Nanomaterial | 納米材料 |
A material defined by the European Commission as ‘A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1–100 nm. In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.’ 由歐盟委員會定義為“含有顆粒的天然、偶然或人造材料，處于未結合狀態或聚集體或凝聚體，其中，對于數量-尺寸分布中的50%或更多顆粒，一個或多個外部尺寸在1-100nm的尺寸范圍內”。在特定情況下，如果考慮到環境、健康、安全或競爭力，50%的數量大小分布閾值可以由1%到50%之間的閾值代替。 |
| Nanoparticles | 納米顆粒 |
Particles with dimensions of order 1 nm which have either been introduced into microstructures for reinforcement or are present as impurities. 尺寸為1nm級的顆粒，其已被引入微結構中用于增強或作為雜質存在。 |
| Nanotechnology | 納米技術 |
The science and engineering of materials that have been structured on length scales of 1–100 nm, resulting in modified physical properties owing to changes in the ratio of surface area to volume (atoms on surfaces having different symmetry from those in the bulk) and because many of the fundamental physical processes that underpin the properties of materials have a characteristic length scale of a few nm, so that alteration of microstructure at the nm level alters the bulk properties. 材料科學與工程，其結構長度為1-100nm，由于表面積與體積之比的變化（表面上的原子與體中的原子具有不同的對稱性），并且支撐材料性質的許多基本物理過程具有幾納米的特征長度尺度，因此改變納米級微觀結構會改變體性質。 |
| Natural aging | 自然時效 |
Spontaneous aging of a supersaturated solid solution at room temperature. 過飽和固溶體在室溫下的自發時效。 |
| Natural unit system (n.u. system) | 自然單位制（n.u.制） |
A non-SI system of units, based on fundamental constants, used in high-energy and particle physics. The n.u. of speed is the speed of light in a vacuum, c0?= 299 792 458 m/s. 基于基本常數的非國際單位制，用于高能和粒子物理n.u.速度是真空中的光速，c0=299792458m/s。 |
| Nautical mile (M) | 海里（M） |
A special unit of distance employed for marine and aerial navigation. The conversion to SI is 1 M = 1 852 m. 用于海上和空中導航的特殊距離單位。SI的轉換為1M＝1852m。 |
| Net weight (Unit N) | 凈重（單位：N） |
The difference between the gross weight of any container including its contents and the tare weight of the empty container. 任何容器（包括其內容物）的毛重與空容器皮重之間的差值。 |
| Neutralization number | 中和值 |
An ASTM number given to quenching oils that reflects the oil’s tendency towards oxidation and sludging. 淬火油的ASTM編號，反映了油的氧化和成泥趨勢。 |
| Newton (N) | 牛頓（N） |
The basic unit of force in the SI system, defined as the force that results in an acceleration of 1 m/s2?when acting on a 1 kg mass. SI國際單位制中力的基本單位，定義為作用于1kg質量時產生1m/s2加速度的力。 |
| Newton’s law of gravitation | 牛頓萬有引力定律 |
(Newton’s law of universal gravitation) Any two bodies exert a gravitational force of attraction F on each other directed along the line joining their centres of mass, in magnitude proportional to the product of their masses and inversely proportional to the square of the distance r between them. （牛頓萬有引力定律）任何兩個物體沿其質心連接線相互施加引力F，其大小與其質量乘積成正比，與它們之間距離r的平方成反比。 |
| Newton’s law of viscosity | 牛頓內摩擦定律 |
The shear stress between two parallel layers of fluid is proportional to the velocity of one relative to that of the other, and inversely proportional to the distance between them. The constant of proportionality is the dynamic viscosity μ. For a Newtonian fluid μ is independent of pressure gradient, shear stress, and strain, but may change with temperature and pressure. 兩個平行流體層之間的剪切應力與其中一層相對于另一層的速度成正比，與它們之間的距離成反比。比例常數是動態粘度μ。對于牛頓流體，μ與壓力梯度、剪切應力和應變無關，但可能隨溫度和壓力而變化。 |
| Nipple | 噴嘴 |
A device containing a non-return valve screwed into a lubrication point through which grease may be introduced, for example into a bearing. 一種包含止回閥的裝置，該止回閥擰入潤滑點，通過該潤滑點可以將潤滑脂引入，例如軸承中。 |
| Noble metals | 貴金屬 |
Metallic elements from periods (rows) 5 and 6 of the periodic table, namely ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold. They resist corrosion and oxidation and are used for electrical contacts, thin-film circuits, and electroplating. Gold, silver, and platinum used for jewellery are also known as precious metals. They have face-centred cubic crystal structure and good ductility. 周期表第5和第6周期（行）中的金屬元素，即釕、銠、鈀、銀、鋨、銥、鉑和金。它們抗腐蝕和氧化，用于電觸點、薄膜電路和電鍍。用于珠寶的金、銀和鉑也被稱為貴金屬。它們具有面心立方晶體結構和良好的延展性。 |
| Nominal diameter | 公稱直徑 |
The ‘‘catalog diameter’’ of a fastener. Usually roughly equal to the diameter of the body, or the outer diameter of the threads. 緊固件的“目錄直徑”。通常大致等于主體的直徑或螺紋的外徑。 |
| Nominal power (Unit kW) | 公稱功率（單位kW） |
1. For an internal combustion engine, the average power output of a typical production engine under normal working conditions measured according to SAE standard J 1349/ISO 1585. 2. For an electric motor, the rated equivalent mechanical power output. 1.對于內燃機，根據SAE標準J 1349/ISO 1585測量的正常工作條件下典型生產發動機的平均功率輸出。2.對于電動機，額定等效機械功率輸出。 |
| Nominal size | 公稱尺寸 |
The intended size of a component. The actual size will depend on manufacturing tolerances. 組件的預期尺寸。實際尺寸取決于制造公差。 |
| Nominal stress | 名義應力 |
The stress at a point calculated on the net cross section by simple elasticity theory without taking into account the effect on the stress produced by stress raisers such as holes, grooves, fillets, etc. 通過簡單彈性理論在凈截面上計算的點處的應力，不考慮孔、槽、圓角等應力提升器產生的應力影響。 |
| Non-ferrous metal | 有色金屬 |
Strictly, all metals and alloys that do not contain iron, but usually taken to mean aluminium- and copper-based alloys. 嚴格來說，所有不含鐵的金屬和合金，但通常指鋁基和銅基合金。 |
| Nonlinear behavior | 非線性行為 |
A fastener or joint system is said to exhibit nonlinear behavior when the relationship between the External load on the joint and deformation of the parts is nonlinear, or when the relationship between increasing Preload and deformation is nonlinear. 當接頭上的外部載荷與零件變形之間的關系是非線性的，或者當增加的預載荷與變形之間的聯系是非線性的時，可以說緊固件或接頭系統表現出非線性行為。 |
| Normal stress (Unit N) | 法向應力（單位：N） |
The stress component perpendicular to a plane on which forces act. Normal stress may be either tensile stress or compressive stress. A stress in a fluid (such as pressure) or a solid, that is perpendicular to the surface on which it acts. The surface may be a real external surface or an imaginary internal one. 垂直于受力平面的應力分量。法向應力可以是拉應力或壓應力。流體（如壓力）或固體中垂直于其作用表面的應力。該表面可以是真實的外表面或假想的內表面。 |
| Normal temperature and pressure (NTP) | 常溫常壓（NTP） |
Reference conditions defined by NIST as 20°C and 1 atm. NIST定義的參考條件為20°C和1atm。 |
| Normality | 常態 |
The principle that the vector sum of plastic strain increments is perpendicular to the yield surface. 塑性應變增量矢量和垂直于屈服面的原理。 |
| Normalizing | 正火 |
Heating a ferrous alloy to a suitable temperature above the transformation range and then cooling in air to a temperature substantially below the transformation range. 將鐵合金加熱至高于轉變范圍的合適溫度，然后在空氣中冷卻至基本低于轉變范圍的溫度。 |
| Notch brittleness | 缺口脆性 |
Susceptibility of a material to brittle fractureat points of stress concentration. For example, in a notch tensile test, the material is said to be notch brittle if the notch strengthis less than the tensile strength of an unnotched specimen. Otherwise, it is said to be notch ductile. 材料在應力集中點易發生脆性斷裂。例如，在缺口拉伸試驗中，如果缺口強度小于無缺口試樣的抗拉強度，則稱材料為缺口脆性材料。否則，稱其為缺口韌性。 |
| Notch depth | 缺口深度 |
The distance from the surface of a notched test specimen to the bottom of the notch. In a cylindrical test specimen, the percentage of the original cross-sectional area removed by machining an annular groove. 從缺口試樣表面到缺口底部的距離。在圓柱形試樣中，通過加工環形槽去除的原始橫截面積的百分比。 |
| Notch ductility | 缺口延展性 |
The percentage reduction in area after complete separation of the metal in a tensile test of a notched specimen. 在缺口試樣的拉伸試驗中，金屬完全分離后的面積減少百分比。 |
| Notch strength | 缺口強度 |
The maximum load on a notched tensile-test specimen divided by the minimum cross-sectional area (the area at the root of the notch). Also known as notch tensile strength. 缺口拉伸試樣上的最大載荷除以最小橫截面積（缺口根部的面積）。也稱為缺口抗拉強度。 |
| Nut | 螺母 |
A metal fastener of square, hexagon or other shape, having an internal thread which screws onto a bolt, stud or arbor. An internally-threaded fastener used with externally-threaded bolts. Usually hexagonal in shape but there is a multitude of other geometries, such as square, for special purposes and different gripping tools. 一種方形、六角形或其他形狀的金屬緊固件，具有內螺紋，可擰在螺栓、螺柱或心軸上。與外螺紋螺栓一起使用的內螺紋緊固件。通常為六邊形，但也有許多其他幾何形狀，如方形，用于特殊用途和不同的夾持工具。 |
| Nut box mechanism | 螺母箱機械裝置 |
In a lathe it is used to engage and disengage the lead screw for thread cutting. This comprises a pair of half-nuts capable of sliding in vertical slides in or out of mesh with the lead screw. 在車床中，它用于接合和分離絲杠以進行螺紋切削。這包括一對半螺母，能夠在與絲杠嚙合的垂直滑動中滑動。 |
| Nut factor | 螺母系數 |
An experimental constant used to evaluate or describe the ratio between the torque applied to a fastener and the Preload achieved as a result. 用于評估或描述施加在緊固件上的扭矩與由此獲得的預載之間的比率的實驗常數。 |
| Nut splitter | 螺母分離器 |
A tool for removing rusted-on and corroded nuts from bolts. It consists of a stiff steel ring that is placed around the nut. A screw thread passing through the ring bears diametrically on a wedged-shape tip that indents and cuts though a face of the nut. 從螺栓上去除銹蝕螺母的工具。它由一個圍繞螺母放置的剛性鋼環組成。穿過環的螺紋徑向支撐在楔形尖端上，該尖端凹陷并穿過螺母的表面。 |
| Nut thickness | 螺母厚度 |
The nut thickness shall be the overall distance measured parallel to the axis of nut, from the top of the nut to the bearing surface, and shall include the thickness of the washer face where provided. 螺母厚度應為平行于螺母軸線測量的從螺母頂部到軸承表面的總距離，還應包括墊圈表面的厚度。 |