第一篇:中英文翻译
特种加工工艺
介绍
传统加工如车削、铣削和磨削等,是利用机械能将金属从工件上剪切掉,以加工成孔或去除余料。特种加工是指这样一组加工工艺,它们通过各种涉及机械能、热能、电能、化学能或及其组合形式的技术,而不使用传统加工所必需的尖锐刀具来去除工件表面的多余材料。
传统加工如车削、钻削、刨削、铣削和磨削,都难以加工特别硬的或脆性材料。采用传统方法加工这类材料就意味着对时间和能量要求有所增加,从而导致成本增加。在某些情况下,传统加工可能行不通。由于在加工过程中会产生残余应力,传统加工方法还会造成刀具磨损,损坏产品质量。基于以下各种特殊理由,特种加工工艺或称为先进制造工艺,可以应用于采用传统加工方法不可行,不令人满意或者不经济的场合:
1.对于传统加工难以夹紧的非常硬的脆性材料; 2.当工件柔性很大或很薄时; 3.当零件的形状过于复杂时;
4.要求加工出的零件没有毛刺或残余应力。
传统加工可以定义为利用机械(运动)能的加工方法,而特种加工利用其他形式的能量,主要有如下三种形式: 1.热能; 2.化学能; 3.电能。
为了满足额外的加工条件的要求,已经开发出了几类特种加工工艺。恰当地使用这些加工工艺可以获得很多优于传统加工工艺的好处。常见的特种加工工艺描述如下。
电火花加工
电火花加工是使用最为广泛的特种加工工艺之一。相比于利用不同刀具进行金属切削和磨削的常规加工,电火花加工更为吸引人之处在于它利用工件和电极间的一系列重复产生的(脉冲)离散电火花所产生的热电作用,从工件表面通过电腐蚀去除掉多余的材料。
传统加工工艺依靠硬质刀具或磨料去除较软的材料,而特种加工工艺如电火花加工,则是利用电火花或热能来电蚀除余料,以获得所需的零件形状。因此,材料的硬度不再是电火花加工中的关键因素。
电火花加工是利用存储在电容器组中的电能(一般为50V/10A量级)在工具电极(阴极)和工件电极(阳极)之间的微小间隙间进行放电来去除材料的。如图6.1所示,在EDM操作初始,在工具电极和工件电极间施以高电压。这个高电压可以在工具电极和工件电极窄缝间的绝缘电介质中产生电场。这就会使悬浮在电介质中的导电粒子聚集在电场最强处。当工具电极和工件电极之间的势能差足够大时,电介质被击穿,从而在电介质流体中会产生瞬时电火花,将少量材料从工件表面蚀除掉。每次电火花所蚀除掉的材料量通常在10-5~10-6mm3范围内。电极之间的间隙只有千分之几英寸,通过伺服机构驱动和控制工具电极的进给使该值保持常量。化学加工
化学加工是众所周知的特种加工工艺之一,它将工件浸入化学溶液通过腐蚀溶解作用将多余材料从工件上去除掉。该工艺是最古老的特种加工工艺,主要用于凹腔和轮廓加工,以及从具有高的比刚度的零件表面去除余料。化学加工广泛用于为多种工业应用(如微机电系统和半导体行业)制造微型零件。
化学加工将工件浸入到化学试剂或蚀刻剂中,位于工件选区的材料通过发生在金属溶蚀或化学溶解过程中的电化学微电池作用被去除掉。而被称为保护层的特殊涂层所保护下的区域中的材料则不会被去除。不过,这种受控的化学溶解过程同时也会蚀除掉所以暴露在表面的材料,尽管去除的渗透率只有0.0025~0.1 mm/min。该工艺采用如下几种形式:凹坑加工、轮廓加工和整体金属去除的化学铣,在薄板上进行蚀刻的化学造型,在微电子领域中利用光敏抗蚀剂完成蚀刻的光化学加工(PCM),采用弱化学试剂进行抛光或去毛刺的电化学抛光,以及利用单一化学活性喷射的化学喷射加工等。如图6.2a所示的化学加工示意图,由于蚀刻剂沿垂直和水平方向开始蚀除材料,钻蚀(又称为淘蚀)量进一步加大,如图6.2b所示的保护体边缘下面的区域。在化学造型中最典型的公差范围可保持在材料厚度的±10%左右。为了提高生产率,在化学加工前,毛坯件材料应采用其他工艺方法(如机械加工)进行预成形加工。湿度和温度也会导致工件尺寸发生改变。通过改变蚀刻剂和控制工件加工环境,这种尺寸改变可以减小到最小。
电化学加工
电化学金属去除方法是一种最有用的特种加工方法。尽管利用电解作用作为金属加工手段是近代的事,但其基本原理是法拉第定律。利用阳极溶解,电化学加工可以去除具有导电性质工件的材料,而无须机械能和热能。这个加工过程一般用于在高强度材料上加工复杂形腔和形状,特别是在航空工业中如涡轮机叶片、喷气发动机零件和喷嘴,以及在汽车业(发动机铸件和齿轮)和医疗卫生业中。最近,还将电化学加工应用于电子工业的微加工中。
图6.3所示的是一个去除金属的电化学加工过程,其基本原理与电镀原理正好相反。在电化学加工过程中,从阳极(工件)上蚀除下的粒子移向阴极(加工工具)。金属的去除由一个合适形状的工具电极来完成,最终加工出来的零件具有给定的形状、尺寸和表面光洁度。在电化学加工过程中,工具电极的形状逐渐被转移或复制到工件上。型腔的形状正好是与工具相匹配的阴模的形状。为了获得电化学过程形状复制的高精度和高的材料去除率,需要采用高的电流密度(范围为10~100 A/cm2)和低电压(范围为8~30V)。通过将工具电极向去除工件表面材料的方向进给,加工间隙要维持在0.1 mm范围内,而进给率一般为0.1~20 mm/min左右。泵压后的电解液以高达5~50 m/s的速度通过间隙,将溶解后的材料、气体和热量带走。因此,当被蚀除的材料还没来得及附着到工具电极上时,就被电解液带走了。
作为一种非机械式金属去除加工方法,ECM可以以高切削量加工任何导电材料,而无须考虑材料的机械性能。特别是在电化学加工中,材料去除率与被加工件的硬度、韧性及其他特性无关。对于利用机械方法难于加工的材料,电化学加工可以保证将该材料加工出复杂形状的零件,这就不需要制造出硬度高于工件的刀具,而且也不会造成刀具磨损。由于工具和工件间没有接触,电化学加工是加工薄壁、易变形零件及表面容易破裂的脆性材料的首选。激光束加工
LASER是英文Light Amplification by Stimulated Emission of Radiation 各单词头一个字母所组成的缩写词。虽然激光在某些场合可用来作为放大器,但它的主要用途是光激射振荡器,或者是作为将电能转换为具有高度准直性光束的换能器。由激光发射出的光能具有不同于其他光源的特点:光谱纯度好、方向性好及具有高的聚焦功率密度。
激光加工就是利用激光和和靶材间的相互作用去除材料。简而言之,这些加工工艺包括激光打孔、激光切割、激光焊接、激光刻槽和激光刻划等。
激光加工(图6.4)可以实现局部的非接触加工,而且对加工件几乎没有作用力。这种加工工艺去除材料的量很小,可以说是“逐个原子”地去除材料。由于这个原因,激光切削所产生的切口非常窄。激光打孔深度可以控制到每个激光脉冲不超过一微米,且可以根据加工要求很灵活地留下非常浅的永久性标记。采用这种方法可以节省材料,这对于贵重材料或微加工中的精密结构而言非常重要。可以精确控制材料去除率使得激光加工成为微制造和微电子技术中非常重要的加工方法。厚度小于20 mm的板材的激光切割加工速度快、柔性好、质量高。另外,通过套孔加工还可有效实现大孔及复杂轮廓的加工。
激光加工中的热影响区相对较窄,其重铸层只有几微米。基于此,激光加工的变形可以不予考虑。激光加工适用于任何可以很好地吸收激光辐射的材料,而传统加工工艺必须针对不同硬度和耐磨性的材料选择合适的刀具。采用传统加工方法,非常难以加工硬脆材料如陶瓷等,而激光加工是解决此类问题的最好选择。
激光切割的边缘光滑且洁净,无须进一步处理。激光打孔可以加工用其他方法难以加工的高深径比的孔。激光加工可以加工出高质量的小盲孔、槽、表面微造型和表面印痕。激光技术正处于高速发展期,激光加工也如此。激光加工不会挂渣,没有毛边,可以精确控制几何精度。随着激光技术的快速发展,激光加工的质量正在稳步提高。
超声加工
超声加工为日益增长的对脆性材料如单晶体、玻璃、多晶陶瓷材料的加工需求及不断提高的工件复杂形状和轮廓加工提供了解决手段。这种加工过程不产生热量、无化学反应,加工出的零件在微结构、化学和物理特性方面都不发生变化,可以获得无应力加工表面。因此,超声加工被广泛应用于传统加工难以切削的硬脆材料。在超声加工中,实际切削由液体中的悬浮磨粒或者旋转的电镀金刚石工具来完成。超声加工的变型有静止(传统)超声加工和旋转超声加工。
传统的超声加工是利用作为小振幅振动的工具与工件之间不断循环的含有磨粒的浆料的磨蚀作用去除材料的。成形工具本身并不磨蚀工件,是受激振动的工具通过激励浆料液流中的磨料不断缓和而均匀地磨损工件,从而在工件表面留下与工具相对应的精确形状。音极工具振动的均匀性使超声加工只能完成小型零件的加工,特别是直径小于100 mm 的零件。
超声加工系统包括音极组件、超声发生器、磨料供给系统及操作人员的控制。音极是暴露在超声波振动中的一小块金属或工具,它将振动能传给某个元件,从而激励浆料中的磨粒。超声加工系统的示意图如图6.5所示。音极/工具组件由换能器、变幅杆和音极组成。换能器将电脉冲转换成垂直冲程,垂直冲程再传给变幅杆进行放大或压抑。调节后的冲程再传给音极/工具组件。此时,工具表面的振动幅值为20~50μm。工具的振幅通常与所使用的磨粒直径大致相等。
磨料供给系统将由水和磨粒组成的浆料送至切削区,磨粒通常为碳化硅或碳化硼。另外,除了提供磨粒进行切削外,浆料还可对音极进行冷却,并将切削区的磨粒和切屑带走。
Nontraditional Machining Processes Introduction
Traditional or conventional machining, such as turning, milling, and grinding etc., uses mechanical energy to shear metal against another substance to create holes or remove material.Nontraditional machining processes are defined as a group of processes that remove excess material by various techniques involving mechanical, thermal, electrical or chemical energy or combinations of these energies but do not use a sharp cutting tool as it is used in traditional manufacturing processes.Extremely hard and brittle materials are difficult to be machined by traditional machining processes.Using traditional methods to machine such materials means increased demand for time and energy and therefore increases in costs;in some cases traditional machining may not be feasible.Traditional machining also results in tool wear and loss of quality in the product owing to induced residual stresses during machining.Nontraditional machining processes, also called unconventional machining process or advanced manufacturing processes, are employed where traditional machining processes are not feasible, satisfactory or economical due to special reasons as outlined below: 1.Very hard fragile materials difficult to clamp for traditional machining;2.When the workpiece is too flexible or slender;3.When the shape of the part is too complex;4.Parts without producing burrs or inducing residual stresses.Traditional machining can be defined as a process using mechanical(motion)energy.Non-traditional machining utilizes other forms of energy;the three main forms of energy used in non-traditional machining processes are as follows: 1.Thermal energy;2.Chemical energy;3.Electrical energy.Several types of nontraditional machining processes have been developed to meet extra required machining conditions.When these processes are employed properly, they offer many advantages over traditional machining processes.The common nontraditional machining processes are described in the following section.Electrical Discharge Machining(EDM)
Electrical discharge machining(EDM)sometimes is colloquially referred to as spark machining, spark eroding, burning, die sinking or wire erosion.It is one of the most widely used non-traditional machining processes.The main attraction of EDM over traditional machining processes such as metal cutting using different tools and grinding is that this technique utilizes thermoelectric process to erode undesired materials from the workpiece by a series of rapidly recurring discrete electrical sparks between workpiece and electrode.The traditional machining processes rely on harder tool or abrasive material to remove softer material whereas nontraditional machining processes such as EDM uses electrical spark or thermal energy to erode unwanted material in order to create desired shapes.So, the hardness of the material is no longer a dominating factor for EDM process.EDM removes material by discharging an electrical current, normally stored in a capacitor bank, across a small gap between the tool(cathode)and the workpiece(anode)typically in the order of 50 volts/10amps.As shown in Fig.6.1, at the beginning of EDM operation, a high voltage is applied across the narrow gap between the electrode and the workpiece.This high voltage induces an electric field in the insulating dielectric that is present in narrow gap between electrode and workpiece.This causes conducting particles suspended in the dielectric to concentrate at the points of strongest electrical field.When the potential difference between the electrode and the workpiece is sufficiently high, the dielectric breaks down and a transient spark discharges through the dielectric fluid, removing small amount of material from the workpiece surface.The volume of the material removed per spark discharge is typically in the range of 10-5 to 10-6 mm3.The gap is only a few thousandths of an inch, which is maintained at a constant value by the servomechanism that actuates and controls the tool feed.Chemical Machining(CM)
Chemical machining(CM)is a well known non-traditional machining process in which metal is removed from a workpiece by immersing it into a chemical solution.The process is the oldest of the nontraditional processes and has been used to produce pockets and contours and to remove materials from parts having a high strength-to-weight ratio.Moreover, the chemical machining method is widely used to produce micro-components for various industrial applications such as microelectromechanical systems(MEMS)and semiconductor industries.In CM material is removed from selected areas of workpiece by immersing it in a chemical reagents or etchants, such as acids and alkaline solutions.Material is removed by microscopic electrochemical cell action which occurs in corrosion or chemical dissolution of a metal.Special coatings called maskants protect areas from which the metal is not to be removed.This controlled chemical dissolution will simultaneously etch all exposed surfaces even though the penetration rates of the material removed may be only 0.0025-0.1mm/min.The basic process takes many forms: chemical milling of pockets, contours, overall metal removal, chemical blanking for etching through thin sheets;photochemical machining(pcm)for etching by using of photosensitive resists in microelectronics;chemical or electrochemical polishing where weak chemical reagents are used(sometimes with remote electric assist)for polishing or deburring and chemical jet machining where a single chemically active jet is used.A schematic of chemical machining process is shown in Fig.6.2a.Because the etchant attacks the material in both vertical and horizontal directions, undercuts may develop(as shown by the areas under the edges of the maskant in Fig.6.2b).Typically, tolerances of ±10% of the material thickness can be maintained in chemical blanking.In order to improve the production rate, the bulk of the workpiece should be shaped by other processes(such as by machining)prior to chemical machining.Dimensional variations can occur because of size changes in workpiece due to humidity and temperature.This variation can be minimized by properly selecting etchants and controlling the environment in the part generation and the production area in the plant.Electrochemical Machining(ECM)
Electrochemical metal removal is one of the more useful nontraditional machining processes.Although the application of electrolytic machining as a metal-working tool is relatively new, the basic principles are based on Faraday laws.Thus, electrochemical machining can be used to remove electrically conductive workpiece material through anodic dissolution.No mechanical or thermal energy is involved.This process is generally used to machine complex cavities and shapes in high-strength materials, particularly in the aerospace industry for the mass production of turbine blades, jet-engine parts, and nozzles, as well as in the automotive(engines castings and gears)and medical industries.More recent applications of ECM include micromachining for the electronics industry.Electrochemical machining(ECM), shown in Fig.6.3, is a metal-removal process based on the principle of reverse electroplating.In this process, particles travel from the anodic material(workpiece)toward the cathodic material(machining tool).Metal removal is effected by a suitably shaped tool electrode, and the parts thus produced have the specified shape, dimensions, and surface finish.ECM forming is carried out so that the shape of the tool electrode is transferred onto, or duplicated in, the workpiece.The cavity produced is the female mating image of the tool shape.For high accuracy in shape duplication and high rates of metal removal, the process is operated at very high current densities of the order 10-100 A/cm2,at relative low voltage usually from 8 to 30 V, while maintaining a very narrow machining gap(of the order of 0.1 mm)by feeding the tool electrode with a feed rate from 0.1 to 20 mm/min.Dissolved material, gas, and heat are removed from the narrow machining gap by the flow of electrolyte pumped through the gap at a high velocity(5-50 m/s), so the current of electrolyte fluid carries away the deplated material before it has a chance to reach the machining tool.Being a non-mechanical metal removal process, ECM is capable of machining any electrically conductive material with high stock removal rates regardless of their mechanical properties.In particular, removal rate in ECM is independent of the hardness, toughness and other properties of the material being machined.The use of ECM is most warranted in the manufacturing of complex-shaped parts from materials that lend themselves poorly to machining by other, above all mechanical methods.There is no need to use a tool made of a harder material than the workpiece, and there is practically no tool wear.Since there is no contact between the tool and the work, ECM is the machining method of choice in the case of thin-walled, easily deformable components and also brittle materials likely to develop cracks in the surface layer.Laser Beam Machining(LBM)
LASER is an acronym for Light Amplification by Stimulated Emission of Radiation.Although the laser is used as a light amplifier in some applications, its principal use is as an optical oscillator or transducer for converting electrical energy into a highly collimated beam of optical radiation.The light energy emitted by the laser has several characteristics which distinguish it from other light sources: spectral purity, directivity and high focused power density.Laser machining is the material removal process accomplished through laser and target material interactions.Generally speaking, these processes include laser drilling, laser cutting, laser welding, and laser grooving, marking or scribing.Laser machining(Fig.6.4)is localized, non-contact machining and is almost reacting-force free.This process can remove material in very small amount and is said to remove material “atom by atom”.For this reason, the kerf in laser cutting is usually very narrow , the depth of laser drilling can be controlled to less than one micron per laser pulse and shallow permanent marks can be made with great flexibility.In this way material can be saved, which may be important for precious materials or for delicate structures in micro-fabrications.The ability of accurate control of material removal makes laser machining an important process in micro-fabrication and micro-electronics.Also laser cutting of sheet material with thickness less than 20mm can be fast, flexible and of high quality, and large holes or any complex contours can be efficiently made through trepanning.Heat Affected Zone(HAZ)in laser machining is relatively narrow and the re-solidified layer is of micron dimensions.For this reason, the distortion in laser machining is negligible.LBM can be applied to any material that can properly absorb the laser irradiation.It is difficult to machine hard materials or brittle materials such as ceramics using traditional methods, laser is a good choice for solving such difficulties.Laser cutting edges can be made smooth and clean, no further treatment is necessary.High aspect ratio holes with diameters impossible for other methods can be drilled using lasers.Small blind holes, grooves, surface texturing and marking can be achieved with high quality using LBM.Laser technology is in rapid progressing, so do laser machining processes.Dross adhesion and edge burr can be avoided, geometry precision can be accurately controlled.The machining quality is in constant progress with the rapid progress in laser technology.Ultrasonic Machining(USM)
Ultrasonic machining offers a solution to the expanding need for machining brittle materials such as single crystals, glasses and polycrystalline ceramics, and for increasing complex operations to provide intricate shapes and workpiece profiles.This machining process is non-thermal, non-chemical, creates no change in the microstructure, chemical or physical properties of the workpiece and offers virtually stress-free machined surfaces.It is therefore used extensively in machining hard and brittle materials that are difficult to cut by other traditional methods.The actual cutting is performed either by abrasive particles suspended in a fluid, or by a rotating diamond-plate tool.These variants are known respectively as stationary(conventional)ultrasonic machining and rotary ultrasonic machining(RUM).Conventional ultrasonic machining(USM)accomplishes the removal of material by the abrading action of a grit-loaded slurry, circulating between the workpiece and a tool that is vibrated with small amplitude.The form tool itself does not abrade the workpiece;the vibrating tool excites the abrasive grains in the flushing fluid, causing them to gently and uniformly wear away the material, leaving a precise reverse from of the tool shape.The uniformity of the sonotrode-tool vibration limits the process to forming small shapes typically under 100 mm in diameter.The USM system includes the Sonotrode-tool assembly, the generator, the grit system and the operator controls.The sonotrode is a piece of metal or tool that is exposed to ultrasonic vibration, and then gives this vibratory energy in an element to excite the abrasive grains in the slurry.A schematic representation of the USM set-up is shown in Fig.6.5.The sonotrode-tool assembly consists of a transducer, a booster and a sonotrode.The transducer converts the electrical pulses into vertical stroke.This vertical stroke is transferred to the booster, which may amplify or suppress the stroke amount.The modified stroke is then relayed to the sonotrode-tool assembly.The amplitude along the face of the tool typically falls in a 20 to 50 μm range.The vibration amplitude is usually equal to the diameter of the abrasive grit used.The grit system supplies a slurry of water and abrasive grit, usually silicon or boron carbide, to the cutting area.In addition to providing abrasive particles to the cut, the slurry also cools the sonotrode and removes particles and debris from the cutting area.
第二篇:中英文翻译
Fundamentals This chapter describes the fundamentals of today’s wireless communications.First a detailed description of the radio channel and its modeling are presented, followed by the introduction of the principle of OFDM multi-carrier transmission.In addition, a general overview of the spread spectrum technique, especially DS-CDMA, is given and examples of potential applications for OFDM and DS-CDMA are analyzed.This introduction is essential for a better understanding of the idea behind the combination of OFDM with the spread spectrum technique, which is briefly introduced in the last part of this chapter.1.1 Radio Channel Characteristics Understanding the characteristics of the communications medium is crucial for the appropriate selection of transmission system architecture, dimensioning of its components, and optimizing system parameters, especially since mobile radio channels are considered to be the most difficult channels, since they suffer from many imperfections like multipath fading, interference, Doppler shift, and shadowing.The choice of system components is totally different if, for instance, multipath propagation with long echoes dominates the radio propagation.Therefore, an accurate channel model describing the behavior of radio wave propagation in different environments such as mobile/fixed and indoor/outdoor is needed.This may allow one, through simulations, to estimate and validate the performance of a given transmission scheme in its several design phases.1.1.1 Understanding Radio Channels In mobile radio channels(see Figure 1-1), the transmitted signal suffers from different effects, which are characterized as follows: Multipath propagation occurs as a consequence of reflections, scattering, and diffraction of the transmitted electromagnetic wave at natural and man-made objects.Thus, at the receiver antenna, a multitude of waves arrives from many different directions with different delays, attenuations, and phases.The superposition of these waves results in amplitude and phase variations of the composite received signal.Doppler spread is caused by moving objects in the mobile radio channel.Changes in the phases and amplitudes of the arriving waves occur which lead to time-variant multipath propagation.Even small movements on the order of the wavelength may result in a totally different wave superposition.The varying signal strength due to time-variant multipath propagation is referred to as fast fading.Shadowing is caused by obstruction of the transmitted waves by, e.g., hills, buildings, walls, and trees, which results in more or less strong attenuation of the signal strength.Compared to fast fading, longer distances have to be covered to significantly change the shadowing constellation.The varying signal strength due to shadowing is called slow fading and can be described by a log-normal distribution [36].Path loss indicates how the mean signal power decays with distance between transmitter and receiver.In free space, the mean signal power decreases with the square of the distance between base station(BS)and terminal station(TS).In a mobile radio channel, where often no line of sight(LOS)path exists, signal power decreases with a power higher than two and is typically in the order of three to five.Variations of the received power due to shadowing and path loss can be efficiently counteracted by power control.In the following, the mobile radio channel is described with respect to its fast fading characteristic.1.1.2 Channel Modeling The mobile radio channel can be characterized by the time-variant channel impulse response h(τ , t)or by the time-variant channel transfer function H(f, t), which is the Fourier transform of h(τ , t).The channel impulse response represents the response of the channel at time t due to an impulse applied at time t − τ.The mobile radio channel is assumed to be a wide-sense stationary random process, i.e., the channel has a fading statistic that remains constant over short periods of time or small spatial distances.In environments with multipath propagation, the channel impulse response is composed of a large number of scattered impulses received over Np different paths,Where
and ap, fD,p, ϕp, and τp are the amplitude, the Doppler frequency, the phase, and the propagation delay, respectively, associated with path p, p = 0,..., Np − 1.The assigned channel transfer function is
The delays are measured relative to the first detectable path at the receiver.The Doppler Frequency
depends on the velocity v of the terminal station, the speed of light c, the carrier frequency fc, and the angle of incidence αp of a wave assigned to path p.A channel impulse response with corresponding channel transfer function is illustrated in Figure 1-2.The delay power density spectrum ρ(τ)that characterizes the frequency selectivity of the mobile radio channel gives the average power of the channel output as a function of the delay τ.The mean delay τ , the root mean square(RMS)delay spread τRMS and the maximum delay τmax are characteristic parameters of the delay power density spectrum.The mean delay is
Where
Figure 1-2 Time-variant channel impulse response and channel transfer function with frequency-selective fading is the power of path p.The RMS delay spread is defined as Similarly, the Doppler power density spectrum S(fD)can be defined that characterizes the time variance of the mobile radio channel and gives the average power of the channel output as a function of the Doppler frequency fD.The frequency dispersive properties of multipath channels are most commonly quantified by the maximum occurring Doppler frequency fDmax and the Doppler spread fDspread.The Doppler spread is the bandwidth of the Doppler power density spectrum and can take on values up to two times |fDmax|, i.e.,1.1.3Channel Fade Statistics The statistics of the fading process characterize the channel and are of importance for channel model parameter specifications.A simple and often used approach is obtained from the assumption that there is a large number of scatterers in the channel that contribute to the signal at the receiver side.The application of the central limit theorem leads to a complex-valued Gaussian process for the channel impulse response.In the absence of line of sight(LOS)or a dominant component, the process is zero-mean.The magnitude of the corresponding channel transfer function
is a random variable, for brevity denoted by a, with a Rayleigh distribution given by
Where
is the average power.The phase is uniformly distributed in the interval [0, 2π].In the case that the multipath channel contains a LOS or dominant component in addition to the randomly moving scatterers, the channel impulse response can no longer be modeled as zero-mean.Under the assumption of a complex-valued Gaussian process for the channel impulse response, the magnitude a of the channel transfer function has a Rice distribution given by
The Rice factor KRice is determined by the ratio of the power of the dominant path to thepower of the scattered paths.I0 is the zero-order modified Bessel function of first kind.The phase is uniformly distributed in the interval [0, 2π].1.1.4Inter-Symbol(ISI)and Inter-Channel Interference(ICI)The delay spread can cause inter-symbol interference(ISI)when adjacent data symbols overlap and interfere with each other due to different delays on different propagation paths.The number of interfering symbols in a single-carrier modulated system is given by
For high data rate applications with very short symbol duration Td < τmax, the effect of ISI and, with that, the receiver complexity can increase significantly.The effect of ISI can be counteracted by different measures such as time or frequency domain equalization.In spread spectrum systems, rake receivers with several arms are used to reduce the effect of ISI by exploiting the multipath diversity such that individual arms are adapted to different propagation paths.If the duration of the transmitted symbol is significantly larger than the maximum delay Td τmax, the channel produces a negligible amount of ISI.This effect is exploited with multi-carrier transmission where the duration per transmitted symbol increases with the number of sub-carriers Nc and, hence, the amount of ISI decreases.The number of interfering symbols in a multi-carrier modulated system is given by
Residual ISI can be eliminated by the use of a guard interval(see Section 1.2).The maximum Doppler spread in mobile radio applications using single-carrier modulation is typically much less than the distance between adjacent channels, such that the effect of interference on adjacent channels due to Doppler spread is not a problem for single-carrier modulated systems.For multi-carrier modulated systems, the sub-channel spacing Fs can become quite small, such that Doppler effects can cause significant ICI.As long as all sub-carriers are affected by a common Doppler shift fD, this Doppler shift can be compensated for in the receiver and ICI can be avoided.However, if Doppler spread in the order of several percent of the sub-carrier spacing occurs, ICI may degrade the system performance significantly.To avoid performance degradations due to ICI or more complex receivers with ICI equalization, the sub-carrier spacing Fs should be chosen as
such that the effects due to Doppler spread can be neglected(see Chapter 4).This approach corresponds with the philosophy of OFDM described in Section 1.2 and is followed in current OFDM-based wireless standards.Nevertheless, if a multi-carrier system design is chosen such that the Doppler spread is in the order of the sub-carrier spacing or higher, a rake receiver in the frequency domain can be used [22].With the frequency domain rake receiver each branch of the rake resolves a different Doppler frequency.1.1.5Examples of Discrete Multipath Channel Models Various discrete multipath channel models for indoor and outdoor cellular systems with different cell sizes have been specified.These channel models define the statistics of the 5 discrete propagation paths.An overview of widely used discrete multipath channel models is given in the following.COST 207 [8]: The COST 207 channel models specify four outdoor macro cell propagation scenarios by continuous, exponentially decreasing delay power density spectra.Implementations of these power density spectra by discrete taps are given by using up to 12 taps.Examples for settings with 6 taps are listed in Table 1-1.In this table for several propagation environments the corresponding path delay and power profiles are given.Hilly terrain causes the longest echoes.The classical Doppler spectrum with uniformly distributed angles of arrival of the paths can be used for all taps for simplicity.Optionally, different Doppler spectra are defined for the individual taps in [8].The COST 207 channel models are based on channel measurements with a bandwidth of 8–10 MHz in the 900-MHz band used for 2G systems such as GSM.COST 231 [9] and COST 259 [10]: These COST actions which are the continuation of COST 207 extend the channel characterization to DCS 1800, DECT, HIPERLAN and UMTS channels, taking into account macro, micro, and pico cell scenarios.Channel models with spatial resolution have been defined in COST 259.The spatial component is introduced by the definition of several clusters with local scatterers, which are located in a circle around the base station.Three types of channel models are defined.The macro cell type has cell sizes from 500 m up to 5000 m and a carrier frequency of 900 MHz or 1.8 GHz.The micro cell type is defined for cell sizes of about 300 m and a carrier frequency of 1.2 GHz or 5 GHz.The pico cell type represents an indoor channel model with cell sizes smaller than 100 m in industrial buildings and in the order of 10 m in an office.The carrier frequency is 2.5 GHz or 24 GHz.COST 273: The COST 273 action additionally takes multi-antenna channel models into account, which are not covered by the previous COST actions.CODIT [7]: These channel models define typical outdoor and indoor propagation scenarios for macro, micro, and pico cells.The fading characteristics of the various propagation environments are specified by the parameters of the Nakagami-m distribution.Every environment is defined in terms of a number of scatterers which can take on values up to 20.Some channel models consider also the angular distribution of the scatterers.They have been developed for the investigation of 3G system proposals.Macro cell channel type models have been developed for carrier frequencies around 900 MHz with 7 MHz bandwidth.The micro and pico cell channel type models have been developed for carrier frequencies between 1.8 GHz and 2 GHz.The bandwidths of the measurements are in the range of 10–100 MHz for macro cells and around 100 MHz for pico cells.JTC [28]: The JTC channel models define indoor and outdoor scenarios by specifying 3 to 10 discrete taps per scenario.The channel models are designed to be applicable for wideband digital mobile radio systems anticipated as candidates for the PCS(Personal Communications Systems)common air interface at carrier frequencies of about 2 GHz.UMTS/UTRA [18][44]: Test propagation scenarios have been defined for UMTS and UTRA system proposals which are developed for frequencies around 2 GHz.The modeling of the multipath propagation corresponds to that used by the COST 207 channel models.HIPERLAN/2 [33]: Five typical indoor propagation scenarios for wireless LANs in the 5 GHz frequency band have been defined.Each scenario is described by 18discrete taps of the delay power density spectrum.The time variance of the channel(Doppler spread)is modeled by a classical Jake’s spectrum with a maximum terminal speed of 3 m/h.Further channel models exist which are, for instance, given in [16].1.1.6Multi-Carrier Channel Modeling Multi-carrier systems can either be simulated in the time domain or, more computationally efficient, in the frequency domain.Preconditions for the frequency domain implementation are the absence of ISI and ICI, the frequency nonselective fading per sub-carrier, and the time-invariance during one OFDM symbol.A proper system design approximately fulfills these preconditions.The discrete channel transfer function adapted to multi-carrier signals results in
where the continuous channel transfer function H(f, t)is sampled in time at OFDM symbol rate s and in frequency at sub-carrier spacing Fs.The duration
s is the total OFDM symbol duration including the guard interval.Finally, a symbol transmitted onsub-channel n of the OFDM symbol i is multiplied by the resulting fading amplitude an,i and rotated by a random phase ϕn,i.The advantage of the frequency domain channel model is that the IFFT and FFT operation for OFDM and inverse OFDM can be avoided and the fading operation results in one complex-valued multiplication per sub-carrier.The discrete multipath channel models introduced in Section 1.1.5 can directly be applied to(1.16).A further simplification of the channel modeling for multi-carrier systems is given by using the so-called uncorrelated fading channel models.1.1.6.1Uncorrelated Fading Channel Models for Multi-Carrier Systems These channel models are based on the assumption that the fading on adjacent data symbols after inverse OFDM and de-interleaving can be considered as uncorrelated [29].This assumption holds when, e.g., a frequency and time interleaver with sufficient interleaving depth is applied.The fading amplitude an,i is chosen from a distribution p(a)according to the considered cell type and the random phase ϕn,I is uniformly distributed in the interval [0,2π].The resulting complex-valued channel fading coefficient is thus generated independently for each sub-carrier and OFDM symbol.For a propagation scenario in a macro cell without LOS, the fading amplitude an,i is generated by a Rayleigh distribution and the channel model is referred to as an uncorrelated Rayleigh fading channel.For smaller cells where often a dominant propagation component occurs, the fading amplitude is chosen from a Rice distribution.The advantages of the uncorrelated fading channel models for multi-carrier systems are their simple implementation in the frequency domain and the simple reproducibility of the simulation results.1.1.7Diversity The coherence bandwidth of a mobile radio channel is the bandwidth over which the signal propagation characteristics are correlated and it can be approximated by
The channel is frequency-selective if the signal bandwidth B is larger than the coherence bandwidth.On the other hand, if B is smaller than , the channel is frequency nonselective or flat.The coherence bandwidth of the channel is of importance for evaluating the performance of spreading and frequency interleaving techniques that try to exploit the inherent frequency diversity Df of the mobile radio channel.In the case of multi-carrier transmission, frequency diversity is exploited if the separation of sub-carriers transmitting the same information exceeds the coherence bandwidth.The maximum achievable frequency diversity Df is given by the ratio between the signal bandwidth B and the coherence bandwidth,The coherence time of the channel is the duration over which the channel characteristics can be considered as time-invariant and can be approximated by
If the duration of the transmitted symbol is larger than the coherence time, the channel is time-selective.On the other hand, if the symbol duration is smaller than , the channel is time nonselective during one symbol duration.The coherence time of the channel is of importance for evaluating the performance of coding and interleaving techniques that try to exploit the inherent time diversity DO of the mobile radio channel.Time diversity can be exploited if the separation between time slots carrying the same information exceeds the coherence time.A number of Ns successive time slots create a time frame of duration Tfr.The maximum time diversity Dt achievable in one time frame is given by the ratio between the duration of a time frame and the coherence time, A system exploiting frequency and time diversity can achieve the overall diversity
The system design should allow one to optimally exploit the available diversity DO.For instance, in systems with multi-carrier transmission the same information should be transmitted on different sub-carriers and in different time slots, achieving uncorrelated faded replicas of the information in both dimensions.Uncoded multi-carrier systems with flat fading per sub-channel and time-invariance during one symbol cannot exploit diversity and have a poor performance in time and frequency selective fading channels.Additional methods have to be applied to exploit diversity.One approach is the use of data spreading where each data symbol is spread by a spreading code of length L.This, in combination with interleaving, can achieve performance results which are given for
by the closed-form solution for the BER for diversity reception in Rayleigh fading channels according to [40]
Whererepresents the combinatory function,and σ2 is the variance of the noise.As soon as the interleaving is not perfect or the diversity offered by the channel is smaller than the spreading code length L, or MCCDMA with multiple access interference is applied,(1.22)is a lower bound.For L = 1, the performance of an OFDM system without forward error correction(FEC)is obtained, 9
which cannot exploit any diversity.The BER according to(1.22)of an OFDM(OFDMA, MC-TDMA)system and a multi-carrier spread spectrum(MC-SS)system with different spreading code lengths L is shown in Figure 1-3.No other diversity techniques are applied.QPSK modulation is used for symbol mapping.The mobile radio channel is modeled as uncorrelated Rayleigh fading channel(see Section 1.1.6).As these curves show, for large values of L, the performance of MC-SS systems approaches that of an AWGN channel.Another form of achieving diversity in OFDM systems is channel coding by FEC, where the information of each data bit is spread over several code bits.Additional to the diversity gain in fading channels, a coding gain can be obtained due to the selection of appropriate coding and decoding algorithms.中文翻译 1基本原理
这章描述今日的基本面的无线通信。第一一个的详细说明无线电频道,它的模型被介绍,跟随附近的的介绍的原则的参考正交频分复用多载波传输。此外,一个一般概观的扩频技术,尤其ds-cdma,被给,潜力的例子申请参考正交频分复用,DS对1。分配的通道传输功能是
有关的延误测量相对于第一个在接收器检测到的路径。多普勒频率
取决于终端站,光速c,载波频率fc的速度和发病路径分配给速度v波αp角度页具有相应通道传输信道冲激响应函数图1-2所示。
延迟功率密度谱ρ(τ)为特征的频率选择性移动无线电频道给出了作为通道的输出功能延迟τ平均功率。平均延迟τ,均方根(RMS)的时延扩展τRMS和最大延迟τmax都是延迟功率密度谱特征参数。平均时延特性参数为
有
图1-2时变信道冲激响应和通道传递函数频率选择性衰落是权力页的路径均方根时延扩展的定义为 同样,多普勒频谱的功率密度(FD)的特点可以定义
在移动时变无线信道,并给出了作为一种金融衍生工具功能的多普勒频率通道输出的平均功率。多径信道频率分散性能是最常见的量化发生的多普勒频率和多普勒fDmax蔓延fDspread最大。多普勒扩散是功率密度的多普勒频谱带宽,可价值观需要两年时间| fDmax|,即
1.1.3频道淡出统计
在衰落过程中的统计特征和重要的渠道是信道模型参数规格。一个简单而经常使用的方法是从假设有一个通道中的散射,有助于在大量接收端的信号。该中心极限定理的应用导致了复杂的值的高斯信道冲激响应过程。在对视线(LOS)或线的主要组成部分的情况下,这个过程是零的意思。相应的通道传递函数幅度
是一个随机变量,通过给定一个简短表示由瑞利分布,有
是的平均功率。相均匀分布在区间[0,2π]。
在案件的多通道包含洛杉矶的或主要组件除了随机移动散射,通道脉冲响应可以不再被建模为均值为零。根据信道脉冲响应的假设一个复杂的值高斯过程,其大小通道的传递函数A的水稻分布给出
赖斯因素KRice是由占主导地位的路径权力的威力比分散的路径。I0是零阶贝塞尔函数的第一阶段是一致kind.The在区间[0,2π]分发。
1.1.4符号间(ISI)和通道间干扰(ICI)
延迟的蔓延引起的符号间干扰(ISI)当相邻的数据符号上的重叠与互相不同的传播路径,由于不同的延迟干涉。符号的干扰在单载波调制系统的号码是给予
对于高数据符号持续时间很短运输署<蟿MAX时,ISI的影响,这样一来,速率应用,接收机的复杂性大大增加。对干扰影响,可以抵消,如时间或频域均衡不同的措施。在扩频系统,与几个臂Rake接收机用于减少通过利用多径分集等,个别武器适应不同的传播路径的干扰影响。
如果发送符号的持续时间明显高于大的最大延迟运输署蟿最大,渠道产生ISI的微不足道。这种效果是利用多载波传输的地方,每发送符号的增加与子载波数控数目,因此,ISI的金额减少的持续时间。符号的干扰多载波调制系统的号码是给予
可以消除符号间干扰由一个保护间隔(见1.2节)的使用。
最大多普勒在移动无线应用传播使用单载波调制通常比相邻通道,这样,干扰对由于多普勒传播相邻通道的作用不是一个单载波调制系统的问题距离。对于多载波调制系统,子通道间距FS可以变得非常小,这样可以造成严重的多普勒效应ICI的。只要所有子载波只要是一个共同的多普勒频移金融衍生工具的影响,这可以补偿多普勒频移在接收器和ICI是可以避免的。但是,如果在对多普勒子载波间隔为几个百分点的蔓延情况,卜内门可能会降低系统的性能显着。为了避免性能降级或因与ICI卜内门更复杂的接收机均衡,子载波间隔财政司司长应定为
这样说,由于多普勒效应可以忽略不扩散(见第4章)。这种方法对应于OFDM的1.2节中所述,是目前基于OFDM的无线标准遵循的理念。
不过,如果多载波系统的设计选择了这样的多普勒展宽在子载波间隔或更高,秩序是在频率RAKE接收机域名可以使用[22]。随着频域RAKE接收机每个支部耙解决了不同的多普勒频率。
1.1.5多径信道模型的离散的例子
各类离散多与不同的细胞大小的室内和室外蜂窝系统的信道模型已经被指定。这些通道模型定义的离散传播路径的统计信息。一种广泛使用的离散多径信道模型概述于下。造价207[8]:成本207信道模型指定连续四个室外宏蜂窝传播方案,指数下降延迟功率密度谱。这些频道功率密度的离散谱的实现都是通过使用多达12个频道。与6频道设置的示例列于表1-1。在这种传播环境的几个表中的相应路径延迟和电源配置给出。丘陵地形导致最长相呼应。
经典的多普勒频谱与均匀分布的到达角路径可以用于简化所有的频道。或者,不同的多普勒谱定义在[8]个人频道。207信道的成本模型是基于一个8-10兆赫的2G,如GSM系统中使用的900兆赫频段信道带宽的测量。造价231[9]和造价259[10]:这些费用是行动的延续成本207扩展通道特性到DCS1800的DECT,HIPERLAN和UMTS的渠道,同时考虑到宏观,微观和微微小区的情况为例。空间分辨率与已定义的通道模型在造价259。空间部分是介绍了与当地散射,这是在基站周围设几组圆的定义。三种类型的通道模型定义。宏细胞类型具有高达500〜5000米,载波频率为900兆赫或1.8 GHz的单元尺寸。微细胞类型被定义为细胞体积约300米,1.2 GHz或5 GHz载波频率。细胞类型代表的Pico与细胞体积小于100工业建筑物和办公室中的10 m阶米室内信道模型。载波频率为2.5 GHz或24千兆赫。造价273:成本273行动另外考虑到多天线信道模型,这是不是由先前的费用的行为包括在内。
CODIT [7]:这些通道模型定义的宏,微,微微蜂窝和室外和室内传播的典型案例。各种传播环境的衰落特性是指定的在NakagamiSS)的不同扩频码L是长度,如图1-3所示的系统。没有其他的分集技术被应用。QPSK调制用于符号映射。移动无线信道建模为不相关瑞利衰落信道(见1.1.6)。由于这些曲线显示,办法,AWGN信道的一对L时,对MC-SS系统性能有很大价值。
另一种实现形式的OFDM系统的多样性是由前向纠错信道编码,在这里,每个数据位的信息分散在几个代码位。附加在衰落信道分集增益,编码增益一个可因适当的编码和解码算法的选择。
第三篇:中英文翻译
蓄电池 battery 充电 converter 转换器 charger
开关电器 Switch electric 按钮开关 Button to switch 电源电器 Power electric 插头插座 Plug sockets
第四篇:中英文翻译机器人
中英文翻译机器人
机器人 工业机器人是在生产环境中用以提高生产效率的工具,它能做常规的装配线工作,或能做那些对于工人来说是危险的工作,例如,第一代工业机器人是用来在核电站中更换核燃料棒,如果人去做这项工作,将会遭受有害放射线的辐射。工业机器人亦能工作在装配线上将小元件装配到一起,如将电子元件安装在电路印刷板,这样,工人就能从这项乏味的常规工作中解放出来。机器人也能按程序要求用来拆除炸弹,辅助残疾人,在社会的很多应用场合履行职能。机器人可以认为是将手臂末端的工具、传感器和(或)手爪移到程序指定位置的一种机器。当机器人到达位置后,他将执行某种任务。这些任务可以是焊接、密封、机器装料、拆卸以及装配工作。除了编程以及系统的开停之外,这些工作可以在无人干预下完成。如下叙述的是机器人系统基本术语: 机器人是一个可编程、多功能的机器手,通过给要完成的不同任务编制各种动作,它可以移动零件、材料、工具以及特殊装置。这个基本定义引导出后续段落的其他定义,从而描绘出一个完整的机器人系统。预编程位置点是机器人为完成工作而必须跟踪的轨迹。在某些位置点上机器人将停下来做某写操作,如装配零件、喷涂油漆或焊接。这些预编程点贮存在机器人的贮存器中,并为后续的连续操作所调用,而且这些预编程点像其他程序数据一样,可在日后随工作需要而变化。因而,正是这种可编程的特征,一个工业机器人很像一台计算机,数据可在这里储存、后续调用与编辑。机械手上机器人的手臂,它使机器人能弯曲、延伸、和旋转,提供这些运动的是机器手的轴,亦是所谓的机器人的自由度。一个机器人能有 3—16 轴,自由度一词总是与机器人轴数相关。工具和手爪不是机器人自身组成部分,但它们安装在机器人手臂末端的附件。这些连在机器人手臂末端的附件可使机器人抬起工件、点焊、刷漆、电弧焊、钻孔、打毛刺以及根据机器人的要求去做各种各样的工作。机器人系统还可以控制机器人的工作单元,工作单元是机器人执行任务所处的整体环境,包括控制器、机械手、工作平台、安全保护装置或者传输装置。所有这些为保证机器人完成自己任务而必需的装置都包括在这一工作单元中。另外,来自外设的信号与机器人通讯,通知机器人何时装配工件、取工件或放工件到传输装置上。机器人系统有三个基本部件:机械手、控制器和动力源。A.机械手 机械手做机器人系统中粗重工作,它包括两个部分:机构和附件,机械手也有联接附件基座,图 1 表示了一机器人基座与附件之间的联接情况。图 1 机械手基座通常在工作区域的地基上,有时基座也可以移动,在这种情况下基座安装在导轨或轨道上,允许机械手从一个位置移动到另外一个位置。正如前面所提到的那样,附件从机器人基座上延伸出来,附件就是机器人的手臂,它可以是直接型,也可以是轴节型手臂,轴节型手臂也是大家所知的关节型手臂。机械臂使机械手产生各轴的运动。这些轴连在一个安装基座上,然后再连到托架上,托架确保机械手停留在某一位置。在手臂的末端上,连接着手腕(图 1),手腕由辅助轴和手腕凸缘组成,手腕是让机器人用户在手腕凸缘上安装不同工具来做不同种工作。机械手的轴使机械手在某一区域内执行任务,我们将这个区域为机器人的工作单元,该区域的大小与机器手的尺寸相对应,(图 2)列举了一个典型装配机器人的工作单元。随着机器人机械结构尺寸的增加。工作单元的范围也必须相应增加。图 2 机械手的运动由执行元件或驱动系统来控制。执行元件或驱动系统允许个轴在工作单元内运动。驱动系统可用电气、液压和气压动力,驱动系统所产生的动力经机构转变为机械能,驱动系统与机械传动链相匹配。有链、齿轮和滚珠丝杠组成的机械传动链驱动着机器人的各轴。B.控制器 机器人控制器是工作单元的核心。控制器储存着预编程序供调用、控制外设,及与厂内计算进行通讯以满足产品经常更新的需要。控制器用于控制机器手运动和在工作单元内控制机器人外设。用户可通过手持的示教盒将机械手运动的程序编入控制器。这些信息储存在控制器的存储器中以备后续调用,控制器储存了机器人系统的所有编程数据,它能储存几个不同的程序,并且所有这些程序均能编辑。控制器要求能够在工作单元内外设进行通信。例如控制器有一个输入端,它能标识某个机加工操作何时完成。当该加工循环完成后,输入端接通,告诉控制器定位机械手以便能抓取已加工工件,随后,机械手抓取一未加工件,将其放置在机床上。接着,控制器给机床发出开始加工的信号。控制器可以由根据事件顺序而步进的机械式轮鼓组成,这种类型的控制器可用在非常简单的机械系统中。用于大多数人系统中的控制器代表现代电子学的水平,是更复杂的装置,即它们是由微处理器操纵的。这些微处理器可以是 8 位,16 位或 32 位处理器。它们可以使得控制器在操纵工程中显非常柔性。控制器能通过通信线发送信号,使它能与机械手各轴交流信息,在机器人的机械手和控制器之间的双向交流信息可以保持操作和位置经常更新,控制器亦能控制安装在机器人手腕上的任何工具。控制器也有与厂内各计算机进行通信的任务,这种通信联系使机器人成为计算机辅助制造(CAM)系统的一个组成部分。存储器。基于微处理器的系统运行时要与固态的存储装置相连,这些存储装置可以是磁泡,随机存储器、软盘、磁带等。每种记忆存储装置均能贮存、编辑信息以备后续调用和编辑。C.动力源 动力源是给机器人和机器手提供动力的单元。传给机器人系统的动力源有两种,一种是用于控制器的交流电,另一种是用于驱动机械手各轴的动力源,例如,如果机器人的机械手是有液压和气动驱动的,控制信号便传送到这些装置中,驱动机器人运动。对于每一个机器人系统,动力是用来操纵机械手的。这些动力可来源与液压动力源、气压动力源或电源,这些能源是机器人工作单元整体的一部分。
robot The industr ial robot is a tool t hat is used in t he manufact ur ing environment to increase product ivit y.It can be used to do rout ine and tedious assembly line jobs, or it can per form jobs t hat might be hazardous to t he human worker.For example ,one of t he first indust r ial robot was used to replace t he nuclear fuel rods in nuclear power plant s.A human doing t his job might be exposed to har mful amount s of radiat ion.The indust r ial robot can also operat e on t he assembly line, putt ing toget her small component s, such as placing electronic component s on a pr int ed circuit board.Thus, t he human worker can be relieved of t he rout ine operat ion of t his t edious t ask.Robot s can also be programmed to defuse bombs, to serve t he handicapped, and to per for m funct ions in numerous applicat ions in our societ y.The robot can be t hought of as a machine t hat will move an endoperat ed.t hese microprocessors are eit her 8-bit , 16-bit ,or 32-bit processors.t his power allows t he controller to be ver y flexible in it s operat ion.The cont roller can send elect ric signals over communicat ion lines t hat allow it to t alk wit h t he var ious axes of t he manipulator.This t wo-way communicat ion bet ween t he robot manipulator and t he cont roller maint ains a const ant updat e of t he end t he operat ion of t he syst em.The cont roller also controls any tooling placed on t he end of t he robot ’s wr ist.The cont roller also has t he job of communicat ing wit h t he different plant comput ers.The communicat ion link est ablishes t he robot as part a comput er-assist ed manufact ur ing(CAM)syst em.As t he basic definit ion st at ed, t he robot is a reprogrammable, mult ifunct ional manipulator.Therefore, t he controller must contain some of memor y stot age.The microprocessor-based syst ems operates in conjunct ion wit h solid-st at e divices.These memor y devices may be magnet ic bubbles, random-access memony, floppy disks,or magnet ic tape.Each memor y storage device stores program infor mat ion fir or for edit ing.C.power suppy The power supply is t he unit t hat supplies power to t he controller and t he manipulator.The t ype of power are delivered to t he robot ic syst em.One t ype of power is t he AC power for operat ion of t he cont roller.The ot her t ype of power is used for dr iving t he var ious axes of t he manipulator.For example, if t he robot manipulator is cont rolled by hydraulic or pneumat ic drives, cont rol singals are sent to t hese devices causing mot ion of t he robot.For each robot ic syst em, power is required to operat e t he manipulator.This power can be developed from eit her a hydraulic power source, a pneumat ic power source,or an elect ric power source.There power sources are part of t he total component s of t he robot ic work cell.
第五篇:建筑结构中英文翻译
A acceptable quality:合格质量 acceptance lot:验收批量 aciera:钢材
admixture:外加剂
against slip coefficient between friction surface of high-strength bolted connection:高强度螺栓摩擦面抗滑移系数 aggregate:骨料 air content:含气量
air-dried timber allowable ratio of height to sectional thickness of masonry wall or column allowable slenderness ratio of steel member allowable slenderness ratio of timber compression member容许长细比 allowable stress range of fatigue allowable ultimate tensile strain of reinforcement allowable value of crack width allowable value of deflection of structural member allowable value of deflection of timber bending member度容许值
allowable value of deformation of steel member allowable value of deformation of structural member allowable value of drift angle of earthquake resistant structure amplified coefficient of eccentricity anchorage anchorage length of steel bar approval analysis during construction stage arch arch with tie rod arch area of shear plane area of transformed section aseismic design assembled monolithic concrete structure automatic welding auxiliary steel bar
B backfilling plate:气干材
:砌体墙、柱容许高厚比
:钢构件容许长细比
:受压木构件:疲劳容许应力幅
:钢筋拉应变限值 :裂缝宽度容许值
:构件挠度容许值 :受弯木构件挠:钢构件变形容许值 :构件变形容许值 :抗震结构层间位移角限值
:偏心距增大系数 :锚具
:钢筋锚固长度
:施工阶段验算 :拱
:拉捍拱
—shaped roof truss:拱形屋架 :剪面面积
:换算截面面积 :建筑抗震设计
:装配整体式混凝土结构 :自动焊接 :架立钢筋 :垫板 balanced depth of compression zone:界限受压区高度 balanced eccentricity:界限偏心距 bar splice:钢筋接头 bark pocket:夹皮 batten plate:缀板 beam:次梁
bearing plane of notch:齿承压面(67)bearing plate:支承板(52)bearing stiffener:支承加劲肋(52)bent-up steel bar:弯起钢筋(35)block:砌块(43)block masonry:砌块砌体(44)block masonry structure:砌块砌体结构(41)blow hole:气孔(62)board:板材(65)bolt:螺栓(54)bolted connection:(钢结构)螺栓连接(59)bolted joint:(木结构)螺栓连接(69)bolted steel structure:螺栓连接钢结构(50)bonded prestressed concrete structure:有粘结预应力混凝土结构(24)bow:顺弯(71)brake member:制动构件(7)breadth of wall between windows:窗间墙宽度(46)brick masonry:砖砌体(44)brick masonry column:砖砌体柱(42)brick masonry structure:砖砌体结构(41)brick masonry wall:砖砌体墙(42)broad—leaved wood:阔叶树材(65)building structural materials:建筑结构材料(17)building structural unit:建筑结构单元(building structure:建筑结构(2 built—up steel column:格构式钢柱(51 bundled tube structure:成束筒结构(3 burn—through:烧穿(62 butt connection:对接(59 butt joint:对接(70)butt weld:对接焊缝(60)
C calculating area of compression member:受压构件计算面积(67)calculating overturning point:计算倾覆点(46)calculation of load-carrying capacity of member:构件承载能力计算(10)camber of structural member:结构构件起拱(22)cantilever beam :挑梁(42)cap of reinforced concrete column:钢筋混凝土柱帽(27)carbonation of concrete:混凝土碳化(30)cast-in—situ concrete slab column structure :现浇板柱结构 cast-in—situ concrete structure:现浇混凝土结构(25)cavitation:孔洞(39)cavity wall:空斗墙(42)cement:水泥(27)cement content:水泥含量(38)cement mortar:水泥砂浆(43)characteriseic value of live load on floor or roof:楼面、屋面活荷载标准值(14)characteristi cvalue o fwindload:风荷载标准值(16)characteristic value of concrete compressive strength:混凝土轴心抗压强度标准值(30)characteristic value of concrete tensile strength:混凝土轴心抗拉标准值(30)characteristic value of cubic concrete compressive strength:混凝土立方体抗压强度标准值(29)characteristic value of earthquake action:地震作用标准值(16)characteristic value of horizontal crane load:吊车水平荷载标准值(15)characteristic value of masonry strength:砌体强度标准值(44)characteristic value of permanent action·:永久作用标准值(14)characteristic value of snowload:雪荷载标准值(15)characteristic value of strength of steel:钢材强度标准值(55)characteristic value of strength of steel bar:钢筋强度标准值(31)characteristic value of uniformly distributed live load:均布活标载标准值(14)
characteristic value of variable action:可变作用标准值(14)characteristic value of vertical crane load:吊车竖向荷载标准值(15)charaeteristic value of material strength:材料强度标准值(18)checking section of log structural member·,:原木构件计算截面(67)chimney:烟囱(3)circular double—layer suspended cable:圆形双层悬索(6)circular single—layer suspended cable:圆形单层悬索(6)circumferential weld:环形焊缝(60)classfication for earthquake—resistance of buildings·:建筑结构抗震设防类别(9)clear height:净高(21)clincher:扒钉(?0)coefficient of equivalent bending moment of eccentrically loaded steel memher(beam-column):钢压弯构件等效弯矩系数(58)cold bend inspection of steelbar:冷弯试验(39)cold drawn bar:冷拉钢筋(28)cold drawn wire:冷拉钢丝(29)cold—formed thin—walled sectionsteel:冷弯薄壁型钢(53)cold-formed thin-walled steel structure·‘:冷弯薄壁型钢结构(50)cold—rolled deformed bar:冷轧带肋钢筋(28)column bracing:柱间支撑(7)combination value of live load on floor or roof:楼面、屋面活荷载组合值(15)compaction:密实度(37)compliance control:合格控制(23)composite brick masonry member:组合砖砌体构件(42)composite floor system:组合楼盖(8)composite floor with profiled steel sheet:压型钢板楼板(8)composite mortar:混合砂浆(43)composite roof truss:组合屋架(8)compostle member:组合构件(8)compound stirrup:复合箍筋(36)compression member with large eccentricity·:大偏心受压构件(32)compression member with small eccentricity·:小偏心受压构件(32)compressive strength at an angle with slope of grain:斜纹承压强度(66)compressive strength perpendicular to grain:横纹承压强度(66)concentration of plastic deformation:塑性变形集中(9)conceptual earthquake—resistant design:建筑抗震概念设计(9)concrete:混凝土(17)concrete column:混凝土柱(26)concrete consistence:混凝土稠度(37)concrete floded—plate structure:混凝土折板结构(26)concrete foundation:混凝土基础(27)concrete mix ratio:混凝土配合比(38)concrete wall:混凝土墙(27)concrete-filled steel tubular member:钢管混凝土构件(8)conifer:针叶树材(65)coniferous wood:针叶树材(65)connecting plate:连接板(52)connection:连接(21)connections of steel structure:钢结构连接(59)connections of timber structure:木结构连接(68)consistency of mortar:砂浆稠度(48)constant cross—section column:等截面柱(7)construction and examination concentrated load:施工和检修集中荷载(15)continuous weld:连续焊缝(60)core area of section:截面核芯面积(33)core tube supported structure:核心筒悬挂结构(3)corrosion of steel bar:钢筋锈蚀(39)coupled wall:连肢墙(12)coupler:连接器(37)coupling wall—beam :连梁(12)coupling wall—column...:墙肢(12)coursing degree of mortar:砂浆分层度(48)cover plate:盖板(52)covered electrode:焊条(54)crack:裂缝(?0)crack resistance:抗裂度(31)crack width:裂缝宽度(31)crane girder:吊车梁(?)crane load:吊车荷载(15)creep of concrete:混凝土徐变(30)crook:横弯(71)cross beam:井字梁(6)cup:翘弯
curved support:弧形支座(51)cylindrical brick arch:砖筒拱(43)
D decay:腐朽(71)decay prevention of timber structure:木结构防腐(70)defect in timber:木材缺陷(70)deformation analysis:变形验算(10)degree of gravity vertical for structure or structural member·:结构构件垂直度(40)degree of gravity vertical forwall surface:墙面垂直度(49)degree of plainness for structural memer:构件平整度(40)degree of plainness for wall surface:墙面平整度(49)depth of compression zone:受压区高度(32)depth of neutral axis:中和轴高度(32)depth of notch:齿深(67)design of building structures:建筑结构设计(8)design value of earthquake-resistant strength of materials:材料抗震强度设计值(1 design value of load—carrying capacity of members·:构件承载能力设计值(1 designations 0f steel:钢材牌号(53 designvalue of material strength:材料强度设计值(1 destructive test:破损试验(40 detailing reintorcement:构造配筋(35 detailing requirements:构造要求(22 diamonding:菱形变形(71)diaphragm:横隔板(52 dimensional errors:尺寸偏差(39)distribution factor of snow pressure:屋面积雪分布系数 dogspike:扒钉(70)double component concrete column:双肢柱(26)dowelled joint:销连接(69)down-stayed composite beam:下撑式组合粱(8)ductile frame:延性框架(2)dynamic design:动态设计(8)E earthquake-resistant design:抗震设计(9:
earthquake-resistant detailing requirements:抗震构造要求(22)effective area of fillet weld:角焊缝有效面积(57)effective depth of section:截面有效高度(33)effective diameter of bolt or high-strength bolt·:螺栓(或高强度螺栓)有效直径(57)
effective height:计算高度(21)effective length:计算长度(21)effective length of fillet weld:角焊缝有效计算长度(48)effective length of nail:钉有效长度(56)effective span:计算跨度(21)effective supporting length at end of beam:梁端有效支承长度(46)effective thickness of fillet weld:角焊缝有效厚度(48)elastic analysis scheme:弹性方案(46)elastic foundation beam:弹性地基梁(11)elastic foundation plate:弹性地基板(12)elastically supported continuous girder·:弹性支座连续梁(u)elasticity modulus of materials:材料弹性模量(18)elongation rate:伸长率(15)embeded parts:预埋件(30)enhanced coefficient of local bearing strength of materials·:局部抗压强度提高系数(14)entrapped air:含气量(38)equilibrium moisture content:平衡含水率(66)equivalent slenderness ratio:换算长细比(57)equivalent uniformly distributed live load·:等效均布活荷载(14)etlectlve cross—section area of high-strength bolt·:高强度螺栓的有效截面积(58)ettectlve cross—section area of bolt:螺栓有效截面面积(57)euler’s critical load:欧拉临界力(56)euler’s critical stress:欧拉临界应力(56)excessive penetration:塌陷(62)
F fiber concrete:纤维混凝仁(28)filler plate:填板门2)fillet weld:角焊缝(61)final setting time:终凝时间()finger joint:指接(69)fired common brick:烧结普通砖(43)fish eye:白点(62)fish—belly beam:角腹式梁(7)fissure:裂缝(?0)flexible connection:柔性连接(22)flexural rigidity of section:截面弯曲刚度(19)flexural stiffness of member:构件抗弯刚度(20)floor plate:楼板(6)floor system:楼盖(6)four sides(edges)supported plate:四边支承板(12)frame structure:框架结构(2)frame tube structure:单框筒结构(3)frame tube structure:框架—简体结构(2)frame with sidesway:有侧移框架(12)frame without sidesway:无侧移框架(12)frange plate:翼缘板(52)friction coefficient of masonry:砌体摩擦系数(44)full degree of mortar at bed joint:砂浆饱满度(48)function of acceptance:验收函数(23)G gang nail plate joint:钉板连接()glue used for structural timberg:木结构用胶 glued joint:胶合接头
glued laminated timber:层板胶合木(¨)glued laminated timber structure:层板胶合结构‘61)grider:主梁((㈠ grip:夹具
grith weld:环形焊缝(6÷))groove:坡口
gusset plate:节点板(52)
H hanger:吊环
hanging steel bar:吊筋 heartwood :心材 heat tempering bar:热处理钢筋(28)height variation factor of wind pressure:风压高度变化系数(16)heliral weld:螺旋形僻缝
high—strength bolt:高强度螺栓
high—strength bolt with large hexagon bea:大六角头高强度螺栓 high—strength bolted bearing type join:承压型高强度螺栓连接,high—strength bolted connection:高强度螺栓连接
high—strength bolted friction—type joint:摩擦型高强度螺栓连接 high—strength holted steel slsteel structure:高强螺栓连接钢结构 hinge support:铰轴支座(51)hinged connection:铰接(21)hlngeless arch:无铰拱(12)hollow brick:空心砖(43)hollow ratio of masonry unit:块体空心率(46)honeycomb:蜂窝(39)hook:弯钩(37)hoop:箍筋(36)hot—rolled deformed bar:热轧带肋钢筋(28)hot—rolled plain bar:热轧光圆钢筋(28)hot-rolled section steel:热轧型钢(53)hunched beam:加腋梁(?)I impact toughness:冲击韧性(18)impermeability:抗渗性(38)inclined section:斜截面(33)inclined stirrup:斜向箍筋(36)incomplete penetration:未焊透(61)incomplete tusion:未溶合(61)incompletely filled groove:未焊满(61)indented wire:刻痕钢丝(29)influence coefficient for load—bearing capacity of compression member:受压构件承载能力影响系数(46)influence coefficient for spacial action :空间性能影响系数(46)initial control:初步控制(22)insect prevention of timber structure:木结构防虫(?o)inspection for properties of glue used in structural member:结构用胶性能检验(71)inspection for properties of masnory units:块体性能检验(48)inspection for properties of mortar:砂浆性能检验(48)inspection for properties of steelbar:钢筋性能检验(39)integral prefabricated prestressed concrete slab—column structure:整体预应力板柱结构(25)intermediate stiffener:中间加劲肋(53)intermittent weld:断续焊缝(60)
J joint of reinforcement:钢筋接头(35)K key joint:键连接(69)kinetic design:动态设计(8)knot:节子(木节)(70)L laced of battened compression member lacing and batten elements lacing bar lamellar tearing lap connectlon lapped length of steel bar large pannel concrete structure large-form cocrete structure lateral bending lateral displacement stiffness of storey lateral displacement stiffness of structure lateral force resistant wallstructure leg size of fillet weld length of shear plane lift light weight aggregate concrete limit of acceptance limitimg value for local dimension of masonry structure limiting value for sectional dimension limiting value for supporting length limiting value for total height of masonry structure限值(47)linear expansion coeffcient lintel load bearing wall load-carrying capacity per bolt load(56)load log log timberstructure long term rigidity of member longitude horizontal bracing longitudinal steel bar:格构式钢柱(51):缀材(缀件)(51):缀条(51)
:层状撕裂(62):叠接(搭接)(59)
:钢筋搭接长度(36)
:混凝土大板结构(25):大模板结构(26):侧向弯曲(40)
:楼层侧移刚度(20)·:结构侧移刚度(20):抗侧力墙体结构(12):角焊缝焊脚尺寸(57):剪面长度(67)—slab structure:升板结构(25)
:轻骨料混凝土(28):验收界限(23)·:砌体结构局部尺寸限值(47)
:截面尺寸限值(47):支承长度限值(47)·:砌体结构总高度:线膨胀系数(18):过梁(7)
:承重墙(7)
:单个普通螺栓承载能力(56)—carrying capacity per high—strength holt:单个高强螺桂承载能力—carrying capacity per rivet:单个铆钉承载能力(55):原木(65)
:原木结构(64)
:构件长期刚度(32):纵向水平支撑(5):纵向钢筋(35)longitudinal stiffener:纵向加劲肋(53)longitudinal weld:纵向焊缝(60)losses of prestress:‘预应力损失(33)lump material:块体(42)
M main axis:强轴(56)main beam·:主梁(6)major axis:强轴(56)manual welding:手工焊接(59)manufacture control:生产控制(22)map cracking:龟裂(39)masonry:砌体(17)masonry lintel:砖过梁(43)masonry member:无筋砌体构件(41)masonry units:块体(43)masonry—concrete structure:砖混结构(¨)masonry—timber structure:砖木结构(11)mechanical properties of materials·:材料力学性能(17)melt—thru:烧穿(62)method of sampling:抽样方法(23)minimum strength class of masonry:砌体材料最低强度等级(47)minor axls·:弱轴(56)mix ratio of mortar:砂浆配合比(48)mixing water:拌合水(27)modified coefficient for allowable ratio of height to sectionalthickness of masonry wall :砌体墙容许高厚比修正系数(47)modified coefficient of flexural strength for timber curved mem—:弧形木构件抗弯强度修正系数(68)modulus of elasticity of concrete:混凝土弹性模量(30)modulus of elasticity parellel to grain:顺纹弹性模量(66)moisture content:含水率(66)moment modified factor:弯矩调幅系数 monitor frame:天窗架 mortar:砂浆
multi—defence system of earthquake—resistant building·:多道设防抗震建筑
multi—tube supported suspended structure:多筒悬挂结构
N nailed joint:钉连接,net height:净高l net span:净跨度
net water/cementratio:净水灰比
non-destructive inspection of weld:焊缝无损检验 non-destructive test:非破损检验 non-load—bearingwall:非承重墙
non—uniform cross—section beam:变截面粱
non—uniformly distributed strain coefficient of longitudinal tensile reinforcement:纵向受拉钢筋应变不均匀系数 normal concrete:普通混凝土 normal section notch and tooth joint number of sampling O obligue section oblique one open web roof truss ordinary concrete ordinary steel bar orthogonal fillet weld outstanding width of flange outstanding width of stiffener over-all stability reduction coefficient of steel beam系数(58)
overlap overturning or slip resistance analysis
P padding plate partial penetrated butt weld partition penetrated butt weld percentage of reinforcement perforated brick pilastered wall pit pith plain concrete structure plane hypothesis plane structure plane trussed lattice grids:正截面
:齿连接 :抽样数量 :斜截面
—angle fillet weld:斜角角焊缝
—way reinforced(or prestressed)concrete slab‘‘:单向板 :空腹屋架,:普通混凝土(28):普通钢筋(29)
:直角角焊缝(61)
:翼缘板外伸宽度(57):加劲肋外伸宽度(57)·:钢梁整体稳定:焊瘤(62)
:抗倾覆、滑移验算(10):垫板(52)
:不焊透对接焊缝(61):非承重墙(7)
:透焊对接焊缝(60):配筋率(34):多孔砖(43):带壁柱墙(42)·:凹坑(62):髓心(?o)
:素混凝土结构(24):平截面假定(32):平面结构(11)
:平面桁架系网架(5)plank:板材(65)plastic adaption coefficient of cross—section:截面塑性发展系数(58)plastic design of steel structure:钢结构塑性设计(56)plastic hinge·:塑性铰(13)plastlcity coefficient of reinforced concrete member in tensile zone:受拉区混凝土塑性影响系数(34)plate—like space frame:干板型网架(5)plate—like space truss:平板型网架(5)plug weld:塞焊缝(60)plywood:胶合板(65)plywood structure:胶合板结构(64)pockmark:麻面(39)polygonal top-chord roof truss:多边形屋架(4)post—tensioned prestressed concrete structure:后张法预应力混凝土结构(24)precast reinforced concrete member:预制混凝土构件(26)prefabricated concrete structure:装配式混凝土结构(25)presetting time:初凝时间(38)prestressed concrete structure:预应力混凝土结构(24)prestressed steel structure:预应力钢结构(50)prestressed tendon:预应力筋<29)pre—tensioned prestressed concrete structure·:先张法预应力混凝土结构(24)primary control:初步控制(22)production control:生产控制(22)properties of fresh concrete:可塑混凝土性能(37)properties of hardened concrete:硬化混凝土性能(38)property of building structural materials:建筑结构材料性能(17)purlin“—””—:檩条(4)
Q qlue timber structurer:胶合木结构(㈠)quality grade of structural timber:木材质量等级(?0)quality grade of weld:焊缝质量级别(61)quality inspection of bolted connection:螺栓连接质量检验(63)quality inspection of masonry:砌体质量检验(48)quality inspection of riveted connection:铆钉连接质量检验(63)quasi—permanent value of live load on floor or roof,:楼面、屋面活荷载准永久值(15)R radial check:辐裂(70)ratio of axial compressive force to axial compressive ultimate capacity of section:轴压比(35)ratio of height to sectional thickness of wall or column:砌体墙柱高、厚比(48)ratio of reinforcement:配筋率(34)ratio of shear span to effective depth of section:剪跨比(35)redistribution of internal force:内力重分布(13)reducing coefficient of compressive strength in sloping grain for bolted connection:螺栓连接斜纹承压强度降低系数(68)reducing coefficient of liveload:活荷载折减系数(14)reducing coefficient of shearing strength for notch and tooth connection:齿连接抗剪强度降低系数(68)regular earthquake—resistant building:规则抗震建筑(9)reinforced concrete deep beam:混凝土深梁(26)reinforced concrete slender beam:混凝土浅梁(26)reinforced concrete structure:钢筋混凝土结构(24)reinforced masonry structure:配筋砌体结构(41)reinforcement ratio:配筋率(34)reinforcement ratio per unit volume:体积配筋率(35)relaxation of prestressed tendon:预应筋松弛(31)representative value of gravity load:重力荷载代表值(17)resistance to abrasion:耐磨性(38)resistance to freezing and thawing:抗冻融性(39)resistance to water penetration·:抗渗性(38)reveal of reinforcement:露筋(39)right—angle filletweld:直角角焊缝(61)rigid analysis scheme:刚性方案(45)rigid connection:刚接(21)rigid transverse wall:刚性横墙(42)rigid zone:刚域(13)rigid-elastic analysis scheme:刚弹性方案(45)rigidity of section:截面刚度(19)rigidly supported continous girder:刚性支座连续梁(11)ring beam:圈梁(42)rivet:铆钉(55)riveted connecction:铆钉连接(60)riveted steel beam:铆接钢梁(52)riveted steel girder:铆接钢梁(52)riveted steel structure:铆接钢结构(50)rolle rsupport:滚轴支座(51)rolled steel beam:轧制型钢梁(51)roof board:屋面板(3)roof bracing system:屋架支撑系统(4)roof girder:屋面梁(4)roof plate:屋面板(3)roof slab:屋面板(3)roof system:屋盖(3)roof truss:屋架(4)rot:腐朽(71)round wire:光圆钢丝(29)
S safety classes of building structures:建筑结构安全等级(9)safetybolt:保险螺栓(69)sapwood:边材(65)sawn lumber+A610:方木(65)sawn timber structure:方木结构(64)saw-tooth joint failure:齿缝破坏(45)scarf joint:斜搭接(70)seamless steel pipe:无缝钢管(54)seamless steel tube:无缝钢管(54)second moment of area of tranformed section:换算截面惯性矩(34)second order effect due to displacement:挠曲二阶效应(13)secondary axis:弱轴(56)secondary beam:次粱(6)section modulus of transformed section:换算截面模量(34)section steel:型钢(53)semi-automatic welding:半自动焊接(59)separated steel column:分离式钢柱(51)setting time:凝结时间(38)shake:环裂(70)shaped steel:型钢(53)shapefactorofwindload:风荷载体型系数(16)shear plane:剪面(67)shearing rigidity of section:截面剪变刚度(19)shearing stiffness of member:构件抗剪刚度(20)short stiffener:短加劲肋(53)short term rigidity of member:构件短期刚度(31)shrinkage:干缩(71)shrinkage of concrete:混凝干收缩(30)silos:贮仓(3)skylight truss:天窗架(4)slab:楼板(6)slab—column structure:板柱结构(2)slag inclusion:夹渣(61)sloping grain:‘斜纹(70)slump:坍落度(37)snow reference pressure:基本雪压(16)solid—web steel column:实腹式钢柱(space structure:空间结构(11)space suspended cable:悬索(5)spacing of bars:钢筋间距(33)spacing of rigid transverse wall:刚性横墙间距(46)spacing of stirrup legs:箍筋肢距(33)spacing of stirrups:箍筋间距(33)specified concrete:特种混凝上(28)spiral stirrup:螺旋箍筋(36)spiral weld:螺旋形焊缝(60)split ringjoint:裂环连接(69)square pyramid space grids:四角锥体网架(5)stability calculation:稳定计算(10)stability reduction coefficient of axially loaded compression:轴心受压构件稳定系数<13)stair:楼梯(8)static analysis scheme of building:房屋静力汁算方案(45)static design:房屋静力汁算方案(45)statically determinate structure:静定结构(11)statically indeterminate structure:超静定结构(11)sted:钢材(17)steel bar:钢筋(28)steel column component:钢柱分肢(51)steel columnbase:钢柱脚(51)steel fiber reinforced concrete structure·:钢纤维混凝土结构(26)steel hanger:吊筋(37)steel mesh reinforced brick masonry member:方格网配筋砖砌体构件(41)steel pipe:钢管(54)steel plate:钢板(53)steel plateelement:钢板件(52)steel strip:钢带(53)steel support:钢支座(51)steel tie:拉结钢筋(36)steel tie bar for masonry:砌体拉结钢筋(47)steel tube:钢管(54)steel tubular structure:钢管结构(50)steel wire:钢丝(28)stepped column:阶形柱(7)stiffener:加劲肋(52)stiffness of structural member:构件刚度(19)stiffness of transverse wall:横墙刚度(45)stirrup:箍筋(36)stone:石材(44)stone masonry:石砌体(44)stone masonry structure:石砌体结构(41)storev height:层高(21)straight—line joint failure:通缝破坏(45)straightness of structural member:构件乎直度(71)strand:钢绞线(2,)strength classes of masonry units:块体强度等级(44)strength classes of mortar:砂浆强度等级(44)strength classes of structural steel:钢材强度等级(55)strength classes of structural timber:木材强度等级(66)strength classes(grades)of concrete:混凝土强度等级(29)strength classes(grades)of prestressed tendon:预应力筋强度等级(30)strength classes(grades)of steel bar :普通钢筋强度等级(30)strength of structural timber parallel to grain:木材顺纹强度(66)strongaxis:强轴(56)structural system composed of bar:”杆系结构(11)structural system composed of plate:板系结构(12)structural wall:结构墙(7)superposed reinforced concrete flexural member:叠合式混凝土受弯构件(26)suspended crossed cable net:双向正交索网结构(6)suspended structure:悬挂结构(3)swirl grain:涡纹(?1)
T tensile(compressive)rigidity of section:截面拉伸(压缩)刚度(19)tensile(compressive)stiffness of member:构件抗拉(抗压)刚度(20)tensile(ultimate)strength of steel:钢材(钢筋)抗拉(极限)强度(18)test for properties of concrete structural members:构件性能检验(40): thickness of concrete cover:混凝土保护层厚度(33)thickness of mortarat bed joint:水平灰缝厚度(49)thin shell:薄壳(6)three hinged arch:三铰拱(n)tie bar:拉结钢筋(36)tie beam,‘:系梁(22)tie tod:系杆(5)tied framework:绑扎骨架(35)timber:木材(17)timber roof truss:木屋架(64)tor-shear type high-strength bolt:扭剪型高强度螺栓(54)torsional rigidity of section:截面扭转刚度(19)torsional stiffness of member:构件抗扭刚度(20)total breadth of structure:结构总宽度(21)total height of structure:结构总高度(21)total length of structure:结构总长度(21)transmission length of prestress:预应力传递长度(36)transverse horizontal bracing:横向水平支撑(4)transverse stiffener·:横向加劲肋(53)transverse weld:横向焊缝(60)transversely distributed steelbar:横向分布钢筋(36)trapezoid roof truss:梯形屋架(4)triangular pyramid space grids:三角锥体网架(5)triangular roof truss:三角形屋架(4)trussed arch:椽架(64)trussed rafter:桁架拱(5)tube in tube structure:筒中筒结构(3)tube structure:简体结构(2)twist:扭弯(71)two hinged arch:双铰拱(11)two sides(edges)supported plate:两边支承板(12)two—way reinforced(or prestressed)concrete slab:混凝土双向板(27)
U ultimate compressive strain of concrete’”:混凝土极限压应变(31)unbonded prestressed concrete structure:无粘结预应力混凝土结构(25)undercut:咬边(62)uniform cross—section beam:等截面粱(6)unseasoned timber:湿材(65)upper flexible and lower rigid complex multistorey building·:上柔下刚多层房屋(45)upper rigid lower flexible complex multistorey building·:上刚下柔多层房屋(45)Vvalue of decompression prestress :预应力筋消压预应力值(33)value of effective prestress:预应筋有效预应力值(33)verification of serviceability limit states· ”:正常使用极限状态验证(10)verification of ultimate limit states :承载能极限状态验证(10)vertical bracing:竖向支撑(5)vierendal roof truss:空腹屋架(4)visual examination of structural member:构件外观检查(39)visual examination of structural steel member:钢构件外观检查(63)visual examination of weld:焊缝外观检查(62)W wall beam:墙梁(42)wall frame:壁式框架(门)wall—slab structure:墙板结构(2)warping:翘曲(40),(71)warping rigidity of section:截面翘曲刚度(19)water retentivity of mortar:砂浆保水性(48)water tower:水塔(3)water/cement ratio·:水灰比(3g)weak axis·:弱轴(56)weak region of earthquake—resistant building:抗震建筑薄弱部位(9)web plate:腹板(52)weld:焊缝(6[))weld crack:焊接裂纹(62)weld defects:焊接缺陷(61)weld roof:焊根(61)weld toe:焊趾(61)weldability of steel bar:钢筋可焊性(39)welded framework:焊接骨架()welded steel beam:焊接钢梁(welded steel girder:焊接钢梁(52)welded steel pipe:焊接钢管(54)welded steel strueture:焊接钢结构(50)welding connection·:焊缝连接(59)welding flux:焊剂(54)welding rod:焊条(54)welding wire:焊丝(54)wind fluttering factor:风振系数(16)wind reference pressure:基本风压(16)wind—resistant column:抗风柱(?)wood roof decking:屋面木基层(64)Y yield strength(yield point)of steel:钢材(钢筋)屈服强度(屈服点)