文档库 最新最全的文档下载
当前位置:文档库 › 移动式数控龙门铣床的总体设计外文文献翻译、中英文翻译、外文翻译

移动式数控龙门铣床的总体设计外文文献翻译、中英文翻译、外文翻译

移动式数控龙门铣床的总体设计外文文献翻译、中英文翻译、外文翻译
移动式数控龙门铣床的总体设计外文文献翻译、中英文翻译、外文翻译

附录3

外文文献

Design of Movable Gantry CNC Milling Machine

ZHANG Jian

Abstract:this paper describes the nc milling roller, the overall design and analyses the bilateralsuper-modulus gear pair of driving mechanism of the main points of design,installationguidesurface of the X axis is introduced in this paper Keywords:mobile nc milling design

T his machine is mainly used for metal parts of the plane and inclined plane work. It has enough rigidity, Milling head adopts milling head in Taiwan, Milling head with flexible, Spindle motor is frequency conversion motor. It can undertake stepless speed, Ensure accuracy of machine tools and machining precision has good stability, This machine is of high efficiency and exercise,For convenience, make the drive more reliable and convenient in maintenance, less consumption, beautiful modelling, etc, widely used in mechanical manufacturing industry.

This paper described the mobile CNC milling refers to longmen framework Vertical milling movement. The biggest advantage of milling roller is (1) Machine cover an area of an area small. Workbench mobile Longmen milling machine, complete machine must be higher than vertical stroke length two times. However, Workbench mobile Longmen milling machine, The length of side frame which is fabricated according to add only longitudinal travel width, The

dynamic response of the machine is good. Workbench mobile Longmen milling machine adopts fixed table. The whole cast out with bed, Longmen framework of longitudinal motionDrive torque equivalent unchanged, It is not because of bearing the weight of the workpiece changesChange, so as to ensure the accuracy and performance of the machine tool.

The independent design mobile nc Longmen milling(FIG 1)has been a special machine to use. It can satisfy the large castings, steel parts boring and milling, drilling, etc multiple operation process. It is right milling head, It also can process the 4 side of workpiece. The goal of the main design parameters such as Longmen milling under: workbench area 1800mm ×4000mm, The travel for X axis:4000mm The travel for Y axis:2000mm The travel forZ axis:750mm, Spindle power 18.5KW, Each axis rapid federate 10m/min.

Figure 1 Mobile nc milling

1.Mechanical parts design

The bed include Bed, Slide, Longmen frame spindle box, Three axis to drive mechanical parts and related CNC servo part, Now ,The design process is

emphasized as follows: The bed is the basic design work, The size of the bed of the design affects the complete machine design. And the rationality of the design of directly affect the whole Machine stiffness. The cross-section shape for the bed like ∏,(FIG 2) The plane is working on a bed of mesa design has 9 T shaped groove. For the convenience of bed and working mesa of pure dig imageT processing, groove tank completely, The right and left two concerning the design has a long narrow swing plane. It is used to linear rolling guide vice, The author put rail surface design in the two side bed. The main consideration of force transmission directions and unloading, Because the bed will be dragon framework of gravity, cutting force and the gravity of the workpiece, This design can directly into the gravity of longmen framework to machine tools, and Bed only suffer the gravity of the workpiece. The bed by the following basic wall thickness determine By the following formula.

C=1/4(2L+B+H)

Type: C,L,B is respectively for bed length, width and height of size and unit for the m.

Based on equivalent size c, Consulting relevant form,Take the basic wall thickness is 38mm,

Figure 2 Shape of concerning the cross-section Spindle box adopts 300 mm ×300 mm section design. The torsion bending

capacity are stronger. Spindle gearboxes USES two gears Gear sliding speed-change mechanism.

It can adapt rough machining requirements. Spindle unit adopts four supporting structure, Ahead three groups of Angle contact ball bearing used to withstand cutting force. Spindle end a deep groove ball bearings are used to unloading, That is not of the Sliding gears of the additional moment.

Longmen framework used integral frame which is fabricated according to the design concept, It took about beam and column design into a whole. Although make casting and assembly adjusting difficulty, the whole framework of longmen rigid better, more important is to slide have assembled spindle box, etc. Slide is designed in the frame which is fabricated according to the geometrical dimensions and spindle box, According to the center axis of the guide bar as far as possible to face for the principle, The Z axis and the driver installation position in design, effectively reduce the weight of the slide.

Designed to drive into the idea as follows, The X axis to drive

Use the bilateral super-modulus gear pair aggravating preloading linear rolling guide vice.X axis and Y axis uses big diameter ball screw preloading vice hardened guide. Rail sliding parts attached engineering plastics, It avoids low when crawling phenomenon, and guide the design is inclined with adjustable device. This machine design make the whole machine to coordinate performance. The axis of the feeding speed and force get the optimal matching.

Due to the longitudinal axis machine movement X, and is moving longmen framework of longmen framework weighed 10T, so the linear rolling guide rails to must choose.Because the ball rail system of small friction coefficient, very suitable for longmen framework of moving rigidity requirement.Guide the slider choose one type, each slide block dynamic load can achieve 10t. Considering the safety coefficient, every guide installation 2 slider. Longmen framework for the driver bilateral super-modulus gear pair (see chart 2), feed movement by 3 input, through two inclined gear motor shaft/and axis to 2, and

then by two gear - and to drive rack. And thus promote longmen framew3 the helical gear axle spiral of the two opposite directions. Through the spring in the shaft on a three axial force F, make the helical gear trace of axial movement produced at 1 and 2 and axial shaft in the opposite direction Angle of small, round 4 and 5) respectively, the gear tooth surface with two rack, eliminate the gap.

1.2.3--- axis 4.5--- Rack

Figure 3 Bilateral super-modulus gear pair

Spindle box and vertical motion Z axis adopts ball screw assembly transmission. Because of this machine is not high speed milling machine, the Z axis of the feeding system for servo motor through the ratio of 4 for parallel axis set than gearbox drives the ball screw rotation. In the design of special attention to the Z axis of safety problems. First choose the servo motor with electromagnetic brake, second in the ball screw with a two-way overrunning clutch, prevent ball nuts rotation caused spindle box mechanical prolapse. Of course, in order to protect the z-axis feed institutions, but also in the accuracy

with two balance on the slide cylinders. Balance Q, etcThe quality of parts in spindle box 85%.

Spindle box around move for the Y axis, in order to guarantee the precision Y axis, and only by their level of ball screw and axial force, servo motor and the ball screw straight league. The author selects the coupling with overload protection device, in the overload when coupling automatically.

2 Selection of CNC system

The Siemens numerical control system is adopted, because this system 840D provides longmen shaft synchronization function. Use this function, the machine can to dragons

Door frame for shaft (into) no, X2 clamps its X1 mechanical deviation of displacement. The actual value can exercise for comparison, even the smallest deviation can be corrected, and therefore improve the accuracy of the X axis movement

3 Epilogue

The author finally, according to the professional machine parts manufacturers to provide design samples design will reach the twice the result with half the effort. In The design process, the author of CNC system, spindle unit, gearbox, super-modulus gear and ball screw guide etc. According to the sample of empirical formulas, not only shorten design time, make the higher reliability. At the same time we must pay great attention to the timely design machine tools, such as the application of three-dimensional software components immediately after the establishment sketches for 3d model, through the assembly interference, machine avoid collisions occur when in assembly Wade rework phenomenon.

[翻译]

移动式数控龙门铣床的总体设计

张坚

摘要:阐述了移动式数控龙门铣床的总体设计,并重点分析了双边齿轮齿条副驱动机构的设计要点,对X轴的导轨安装面作了介绍。

关键词:移动式数控龙门铣床设计

本文所述的移动式数控龙门铣床是指龙门框架作纵向移动的龙门铣床。移动式龙门铣床的最大优点是:

(1)机床占地面积小。工作台移动式龙门铣床,整机长度必须两倍于纵向行程长度,而移动式龙门铣床的整机长度只需纵向行程加上龙门架侧面宽度即可。

(2)机床的动态响应好。移动式龙门铣床采用的是固定工作台,一般与床身整体铸出,龙门框架纵向运动的驱动力矩等值不变,不会因工件的承载重量的改变而变化,从而保证了加工精度和机床的响应性能。笔者独立设计的移动式数控龙门铣床(图1),现已作为专机投入生产应用,能满足大型铸件、钢件的镗、铣、钻等多工序加工;配上直角铣头,还可对工件的个侧面进行加工。由于设计思想正确,配套零部件质量过关,该机床各项指标均已达到数控龙门铣床相关国家标准的要求。该龙门铣床的主要设计参数如下:工作台面积为1800mmX4000mm,X轴行程为4000mm,Y轴行程为2000mm,Z 轴行程为750mm,主轴功率18.5KW,各轴快速进给为10m/min。

1.机械部分设计

整机分为床身、龙门架、滑台、主轴箱、三轴进给驱动机构机械部分及相关数控伺服部分。现把设计过程中的重点阐述如下:

床身是本次设计工作的基础,床身的尺寸设计影响着对整机的设计,而且设计的合理性直接影响到整机的刚度。床身的截面形状为∏形(图1)。床身的上平面即工作台面设计有9条T形槽,为方便床身工作台面和T形槽的精刨加工,槽完全贯通。床身的左、右两下脚各设计有一个狭长平面,用来安放滚动直线导轨副。笔者把导轨面设计在床身的两下侧,主要是考虑力的传递方向与卸荷问题。因床身会受到龙门框架的重力、切削力和工件的重力,这样的设计可使龙门框架的重力直接传入到机床的基础上,而床身只受到工件的重力。床身的基本壁厚由以下公式初定:

C=1/4(2L+B+H)

式中:L. B. H 分别为床身的长、宽、高尺寸,单位为m。根据当量尺寸C,查阅相关表格(略),取基本壁厚为38mm。

主轴箱采用.300mmX300mm 截面设计,其抗扭抗弯能力更强。主轴变速

箱采用两档滑移齿轮变速机构,可适应粗精加工需求。主轴单元采用4支承结构,前面三组角接触球轴承用来承受切削力,主轴尾部一个深沟球轴承用来卸荷,使主轴不受到滑移齿轮产生的附加力矩的影响。

龙门框架采用的是整体龙门架的设计概念,即把横梁与左右立柱设计成一体,虽然使铸造和装配调整时的难度加大,但整体龙门框架的刚性更好,更重要的是使主轴箱、滑台等部件有了装配基准。

滑台的设计是在龙门架和主轴箱的几何尺寸确定后,按照主轴的中心尽量贴近横梁上的导轨面为原则,并把Z轴驱动安装位置设计在滑台上,有效地减轻了滑台的重量。

设计进给驱动机构的构思如下:X轴的进给驱动机构采用双边齿轮齿条副加重预压滚动直线导轨副,Y轴与X轴采用大直径预压滚珠丝杠副加硬导轨副,且导轨滑动部分贴有工程塑料,避免低速时产生爬行现象,而且导轨部分设计有斜镶条可调装置。这样设计使机床的整体进给性能得以协调,各轴的进给速度和进给力得到了最佳匹配。

由于机床的纵向运动X轴是龙门框架移动,而龙门框架重达10t,所以导轨必须选用直线滚动导轨。因为滚动导轨副的摩擦系数小,非常适合龙门框架移动的动静刚度要求。导轨的滑块选用加长加宽型,每个滑块的动载荷可达到10t。考虑到安全系数,每根导轨安装3个滑块。龙门框架的驱动源为双

边齿轮齿条副(见图3),进给运动由轴2输入,通过两对斜齿轮将运动传给轴1和轴3,然后由两个直齿轮4和5去传动齿条,从带动龙门框架移动。轴2上两个斜齿轮的螺旋线的方向相反。通过弹簧在轴2上作用一个轴向力F,使斜齿轮产生微量的轴向移动,这时轴1和轴3便以相反的方向转过微小的角度,使齿轮4和5分别与齿条的两齿面贴紧,消除了间隙。

主轴箱的上下垂直运动Z轴采用滚珠丝杠副传动。由于本机床不是高速铣床,Z轴的进给系统为伺服电动机通过传动比为4的平行轴定比齿轮箱带动滚珠丝杠旋转。笔者在设计中特别注意Z轴的安全问题。首先选用带电磁刹车的伺服电动机,其次在滚珠丝杠上装有一双向超越离合器,防止滚珠螺母自转引起主轴箱机械式下垂。当然,为了保护Z轴进给机构的精度,还在滑台上装有两个平衡油缸。平衡力Q等于主轴箱部件质量的85%。

主轴箱的左右移动为Y轴,为了保证Y轴的传动精度,并使丝杠只受水平轴向力,故采用伺服电动机与滚珠丝杠直联方式。笔者选用的联轴器带有过

载保护装置,在过载时联轴器会自动脱开。

2.数控系统选型

数控系统采用的是西门子840D,因为此系统提供了龙门轴的同步功能。使用此功能,本机床可以对龙门框架进给轴(X1,X2)实现无机械偏差的位移。运动的实际值可进行连续比较,即使最小的偏差也可以得到纠正,因此提高了X轴的运动精度。

3.结语

笔者最后要说明的是,根据专业机床零部件厂商提供的设计样本进行设计会达到事半功倍的效果。在此次设计过程中,笔者对数控系统、主轴单元、变速箱、齿轮齿条和丝杠导轨等都按照样本上的经验公式得出,不仅大大缩短了设计时间,同时使设计的可靠性更高。同时在设计机床中要注重适时应用三维软件,如在部件草图确立后就应立即进行三维模型装配,通过进行装配干涉检查,避免机床在装配时出现的碰撞干涉返工现象。

ZigBee技术外文翻译

ZigBee:无线技术,低功耗传感器网络 加里莱格 美国东部时间2004年5月6日上午12:00 技师(工程师)们在发掘无线传感器的潜在应用方面从未感到任何困难。例如,在家庭安全系统方面,无线传感器相对于有线传感器更易安装。而在有线传感器的装置通常占无线传感器安装的费用80%的工业环境方面同样正确(适用)。而且相比于有线传感器的不切实际甚至是不肯能而言,无线传感器更具应用性。虽然,无线传感器需要消耗更多能量,也就是说所需电池的数量会随之增加或改变过于频繁。再加上对无线传感器由空气传送的数据可靠性的怀疑论,所以无线传感器看起来并不是那么吸引人。 一个低功率无线技术被称为ZigBee,它是无线传感器方程重写,但是。一个安全的网络技术,对最近通过的IEEE 802.15.4无线标准(图1)的顶部游戏机,ZigBee的承诺,把无线传感器的一切从工厂自动化系统到家庭安全系统,消费电子产品。与802.15.4的合作下,ZigBee提供具有电池寿命可比普通小型电池的长几年。ZigBee设备预计也便宜,有人估计销售价格最终不到3美元每节点,。由于价格低,他们应该是一个自然适应于在光线如无线交换机,无线自动调温器,烟雾探测器和家用产品。 (图1)

虽然还没有正式的规范的ZigBee存在(由ZigBee联盟是一个贸易集团,批准应该在今年年底),但ZigBee的前景似乎一片光明。技术研究公司 In-Stat/MDR在它所谓的“谨慎进取”的预测中预测,802.15.4节点和芯片销售将从今天基本上为零,增加到2010年的165万台。不是所有这些单位都将与ZigBee结合,但大多数可能会。世界研究公司预测的到2010年射频模块无线传感器出货量4.65亿美量,其中77%是ZigBee的相关。 从某种意义上说,ZigBee的光明前途在很大程度上是由于其较低的数据速率20 kbps到250 kbps的,用于取决于频段频率(图2),比标称1 Mbps的蓝牙和54的802.11g Mbps的Wi - Fi的技术。但ZigBee的不能发送电子邮件和大型文件,如Wi - Fi功能,或文件和音频,蓝牙一样。对于发送传感器的读数,这是典型的数万字节数,高带宽是没有必要,ZigBee的低带宽有助于它实现其目标和鲁棒性的低功耗,低成本。 由于ZigBee应用的是低带宽要求,ZigBee节点大部分时间可以睡眠模式,从而节省电池电源,然后醒来,快速发送数据,回去睡眠模式。而且,由于ZigBee 可以从睡眠模式过渡到15毫秒或更少主动模式下,即使是睡眠节点也可以达到适当的低延迟。有人扳动支持ZigBee的无线光开关,例如,将不会是一个唤醒延迟知道前灯亮起。与此相反,支持蓝牙唤醒延迟通常大约三秒钟。 一个ZigBee的功耗节省很大一部分来自802.15.4无线电技术,它本身是为低功耗设计的。 802.15.4采用DSSS(直接序列扩频)技术,例如,因为(跳频扩频)另类医疗及社会科学院将在保持一样使用它的频率过大的权力同步。 ZigBee节点,使用802.15.4,是几个不同的沟通方式之一,然而,某些方面比别人拥有更多的使用权力。因此,ZigBee的用户不一定能够实现传感器网络上的任何方式选择和他们仍然期望多年的电池寿命是ZigBee的标志。事实

中英文文献翻译-加工中心数控技术

加工中心数控技术 出处:数控加工中心的分类以及各自特点 出版社:化学工业出版社; 第1版 (2009年3月16日) 作者:徐衡、段晓旭 加工中心是典型的集高技术于一体的机械加工设备,它的发展代表了一个国家设计制造的水平也大大提高了劳动生产率,降低了劳动成本,改善了工人的工作环境,降低了工人的劳动强度。本文经过对不同运动方案和各部件的设计方案的定性分析比较确定该教立式加工中心的进给传动方案为:采用固定床身,电主轴通过安装座安装在床身导轨的滑座上,床身导轨采用滚动导轨,可以实现Y 方向的进给运动。由X-Y双向精密数控工作台带动工件完成X,Y两个方向的进给运动;X,Y,Z三个方向的进给运动均滚珠丝杠,并由交流伺服电机驱动。导轨、滚珠丝杠有相应的润滑、防护等装置。 加工中心(英文缩写为CNC 全称为Computerized Numerical Control):是带有刀库和自动换刀装置的一种高度自动化的多功能数控机床。在中国香港,台湾及广东一代也有很多人叫它电脑锣。 工件在加工中心上经一次装夹后,数字控制系统能控制机床按不同工序,自动选择和更换刀具,自动改变机床主轴转速、进给量和刀具相对工件的运动轨迹及其他辅助机能,依次完成工件几个面上多工序的加工。并且有多种换刀或选刀功能,从而使生产效率大大提高。 加工中心数控机床是一种装有计算机数字控制系统的机床,数控系统能够处理加工程序,控制机床完成各种动作。与普通机床相比,数控机床能够完成平面曲线和空间曲面的加工,加工精度和生产效率都比较高,因而应用日益广泛。 数控机床的组成 一般来说,数控机床由机械部分、数字控制计算机、伺服系统、PC控制部分、液压气压传动系统、冷却润滑和排泄装置组成。数控机床是由程序控制的,零件的编程工作是数控机床加工的重要组成部分。伺服系统是数控机床的驱动部分,计算机输出的控制命令是通过伺服系统产生坐标移动的。普通的立式加工中心有三个伺服电机,分别驱动纵向工作台、横向工作台、主轴箱沿X向、Y向、Z向运动。X、Y、Z是互相垂直的坐标轴,因而当机床三坐标联动时可以加工空

零售企业营销策略中英文对照外文翻译文献

零售企业营销策略中英文对照外文翻译文献(文档含英文原文和中文翻译)

译文: 零售企业的营销策略 Philip Kotlor 今天的零售商为了招徕和挽留顾客,急欲寻找新的营销策略。过去,他们挽留顾客的方法是销售特别的或独特的花色品种,提供比竞争对手更多更好的服务提供商店信用卡是顾客能赊购商品。可是,现在这一切都已变得面目全非了。现在,诸如卡尔文·克连,依佐和李维等全国性品牌,不仅在大多数百货公司及其专营店可以看到,并且也可以在大型综合商场和折扣商店可以买到。全国性品牌的生产商为全力扩大销售量,它们将贴有品牌的商品到处销售。结果是零售商店的面貌越来越相似。 在服务项目上的分工差异在逐渐缩小。许多百货公司削减了服务项目,而许多折扣商店却增加了服务项目。顾客变成了精明的采购员,对价格更加敏感。他们看不出有什么道理要为相同的品牌付出更多的钱,特别是当服务的差别不大或微不足道时。由于银行信用卡越来越被所有的商家接受,他们觉得不必从每个商店赊购商品。 百货商店面对着日益增加的价格的折扣店和专业商店的竞争,准备东山再起。历史上居于市中心的许多商店在郊区购物中心开设分店,那里有宽敞的停车场,购买者来自人口增长较快并且有较高收入的地区。其他一些则对其商店形式进行改变,有些则试用邮购盒电话订货的方法。超级市场面对的是超级商店的竞争,它们开始扩大店面,经营大量的品种繁多的商品和提高设备等级,超级市场还增加了它们的促销预算,大量转向私人品牌,从而增加盈利。 现在,我们讨论零售商在目标市场、产品品种和采办、服务以及商店气氛、定价、促销和销售地点等方面的营销策略。 一、目标市场 零售商最重要的决策时确定目标市场。当确定目标市场并且勾勒出轮廓时,零售商才能对产品分配、商店装饰、广告词和广告媒体、价格水平等作出一致的决定。如沃尔玛的目标市场相当明确:

信息技术英文缩写与解释

AVI 影音文件Audio Video Interleaved 声音图象交叉存取。AVI是一种微软媒体文件格式,类似于MPEG和QuickTime。在AVI中,声音和图象是交叉的存取在一个文件中的每个段的。 ADSL 非对称数字用户线路 非对称数字用户线路。这种DSL叫做非对称DSL,将成为广大家庭和小型商业客户最熟悉的一种DSL。ADSL之所以叫做非对称是因为它的两个双工通道都用来向用户传输数据。仅有很小一部分带宽用来回送用户的信息。然而,大部Internet 特别是富于图形和多媒体Web 数据需要很大的下传带宽,同时用户信息相对比较少,上传的带宽也不要很大。使用ADSL时,下传的速率可以达到6.1 Mbps,而上传速率也可以达到640 Kbps。高的下传速率意味着您的电话可以传输动画,声音和立体图形。另外,一小部分的带宽可以用来传输语音信号,您可以同时打电话而不用再使用第二条电话线。不象电视线路提供的相同的服务,使用ADSL,您不需要和您的邻居争用带宽。有时候,现有的电话线可以使用ADSL,而有时候却要升级,除非电话公司提供了无分离器的ADSL,您就必须安装一个DSL调制解调器。 ASP (Application Services Provider) 应用服务提供商 是指配置、租赁、管理应用解决方案,它是随着外包趋势、软件应用服务和相关业务的发展而逐渐形成的。ASP具有三大特点:首先,ASP向用户提供的服务应用系统本身的所有权属ASP,用户租用服务之后对应用系统拥有使用权;并且,应用系统被集中放置在ASP的IDC(Internet数据服务中心)中,具有充足的带宽、电力和空间保证以及具有专业质量的系统维护服务;ASP定期向用户收取服务费。应用服务提供商将以全新的方式推动应用服务产业的巨大发展。ATM (Asynchronous Transmission Mode) 异步传输模式 这是为满足宽带综合业务数据通信,在分组交换技术的基础上迅速发展起来的通信新技术。可以实现语音、数据、图像、视频等信号的高速传输。 AI (Artificial Intelligent) 人工智能 是计算机科学的一门研究领域。它试图赋予计算机以人类智慧的某些特点,用计算机来模拟人的推理、记忆、学习、创造等智能特征,主要方法是依靠有关知识进行逻辑推理,特别是利用经验性知识对不完全确定的事实进行的精确性推理。 AD 网上广告 指一则按规定象素尺寸或字节数设定的标语或图像,通常是以动画表现的。 Baseband 基带 在该方式中,电压脉冲直接加到电缆,并且使用电缆的整个信号频率范围。基带与宽带传输相比较,宽带传输中,来自多条信道的无线信号调制到不同的“载波”频率上,带宽被划分为不同信道,每信道上的频率范围一定。LocalTalk及以太网都是基带网络,一次仅传输一个信号,电缆上信号电平的改变表示数字值0或者1。使用电缆的整个带宽建立起两个系统间的通信对话,然后两个系统轮流传送。在此期间,共享电缆的其它系统不能传送。基带传输系统中的直流信号往往由于电阻、电容等因素而衰减。另外马达、荧光灯等电子设备产生的外部电磁干扰也会加快信号的衰减。传输率越高,信号就越容易被衰减。为此,以太网等建网标准规定了网络电缆类型、电缆屏蔽、电缆距离、传输率以及在大部分环境中提供相对无差错服务的有关细节。 BBS (Bulletin Board System) 电子公告板 这是因特网提供的一种信息服务,为用户提供一个公用环境,以使寄存函件,读取通告,参与讨论和交流信息。Bluetooth 蓝牙(一种无线通信的标准) 蓝牙技术涉及一系列软硬件技术、方法和理论,包括:无线通信与网络技术,软件工程、软件可靠性理论,协议的正确性验证、形式化描述和一致性与互联测试技术,嵌入式实时操作系统(Embedded RTOS),跨平台开发和用户界面图形化技术,软/硬件接口技术(如RS232,UART,USB等),高集成、低功耗芯片技术等。蓝牙的目标是要提供一种通用的无线接口标准,用微波取代传统网络中错综复杂的电缆,在蓝牙设备间实现方便快捷、灵活安全、低成本低功耗的数据和话音通信。因此,其载频选用在全球都可用的2.45GHz ISM(工业、科学、医学)频带。 CA (Certificate Authority)认证中心 是在线交易的监督者和担保人,主要进行电子证书管理、电子贸易伙伴关系建立和确认、密钥管理、为支付系统中的各参与方提供身份认证等。CA类似于现实生活中公证人的角色,具有权威性,是一个普遍可信的第三方。

机械类数控车床外文翻译外文文献英文文献车床.doc

Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up

市场营销价格策略外文翻译文献

市场营销价格策略外文翻译文献(文档含英文原文和中文翻译)

DESIGNING PRICING STRATEGIES All for-profit organizations and many nonprofit organizations set prices on their goods or services. Whether the price is called rent (for an apartment), tuition (for education), fare (for travel), or interest (for borrowed money), the concept is the same. Throughout most of history, prices were set by negotiation between buyers and sellers. Setting one price for all buyers arose with the development of large-scale retailing at the en d of the nineteenth century, when Woolworth’s and other stores followed a “strictly one-price policy” because they carried so many items and had so many employees. Now, 100 years later, technology is taking us back to an era of negotiated pricing. The Internet, corporate networks, and wireless setups are linking people, machines, and companies around the globe, connecting sellers and buyers as never before. Web sites like https://www.wendangku.net/doc/636907980.html, and https://www.wendangku.net/doc/636907980.html, allow buyers to compare products and prices quickly and easily. On-line auction sites like https://www.wendangku.net/doc/636907980.html, and https://www.wendangku.net/doc/636907980.html, make it easy for buyers and sellers to negotiate prices on thousands of items. At the same time, new tech- nologies are allowing sellers to collect detailed data about customers’ buying habits, preferences—even spending limits—so they can tailor their products and prices. 1 In the entire marketing mix, price is the one element that produces revenue; the others produce costs. Price is also one of the most ?exible elements: It can be changed quickly, unlike product features and channel commitments. Although price competi- tion is a major problem facing companies, many do not handle pricing well. The most common mistakes are these: Pricing is too cost-oriented; price is not revised often

微信营销外文翻译

正确地点和时间下新媒体伴随的社会营销Jay M. Bernhardt 佛罗里达大学健康教育与行为系,佛罗里达州Gainesville Darren Mays乔治敦大学医学中心肿瘤科,哥伦比亚特区华盛顿Amanda K. Hall佛罗里达大学健康教育与行为系,佛罗里达州Gainesville 摘要: 目的:本文的目的是寻求讨论新媒体革命以何种方式将“渠道”更贴近消费者从而提高社会营销。 研究思路:这篇论文描述当前有关的社交媒体和移动通信技术的新媒体发展趋势,并通过运用商业营销,社会变革和公众健康实例分析讨论其对社会营销产生的影响。 成果:快速增长的在线社交网络和世界大部分地区无处不在的手机为社会营销人员提供了巨大的潜力,以全新方式吸引消费者。这些新的通信平台的性质不同于传统媒体是可以使他们更有效地为市场营销服务,最明显的是更深层次消费者参与、多方位信息交流、和基于位置跟踪和消息传递的重要方式。 现实作用:本文所描述的趋势正在快速,从根本上改变商业营销人员、品牌经理和客户关系经理如何与当前的和潜在的消费者相处。社会营销活动应该从中学习,并利用这些新媒体更深入地联系大量的消费者,上述从业人员比以往任何时候都更接近“正确的地点和正确的时间”。 独创性/价值:本文探讨已经介绍了在爱尔兰都柏林的全球非营利和社会营销大会于2011年4月的一个话题。讨论应鼓励社会营销重新考虑“渠道”的作用,并探讨新媒体如何令地方更贴近消费者。 关键词:社会营销,新媒体,社交媒体,移动电话,4P理论,移动通信系统 市场营销组合(或4P理论)是旨在鼓励行为改变的社会营销计划规划和实施的中心结构(Grier and Bryant,2005)。尽管价格、产品和促销策略通常是社会营销活动的主要元素,达到期望的目标受众的地方卫生决策往往是一个挑战(GrierandKumanyika,2010)。地方经常困惑在营销组合那些寻求社会营销作为一个框架申请健康行为改变。常见的想法是,位置被定义为地理位置,然而,在社会营销不一定是一个人的业务所在处或其中一个产品的销售点,而是消费者的利益做出决定并采取行动(Storey et al., 2008)。 新的通信媒体能给社会营销个性化的机会,接触目标消费者在关键行为决策点。这些新媒体为社会营销人员提供多个移动渠道到达消费者在非常情况下做出决定,通过创建直接,双向沟通渠道。这些双向交流现在可以发生在实时决策是在何时何地。第一次社会营销人员可以利用这些新渠道接触数以千计甚至数以百万计的人们在相对较低的成本促进健康的生活方式和影响社会变革(Thackeray et al., 2008)。 传统上,社会营销努力促进健康行为改变很大程度上依赖于地方定义为物理位置来分发产品(KreuterandBernhardt,2009)。他们在公共厕所上放置安全套自动售货机推广安全性行为或将营养标志放置在杂货店以期说服客户选择更健康的食品(Storey et al., 2008)。这些例子需要大量投资时间和物质资源从而成功地到达消费者。此外,确定一个是否会购买和使用避孕套或者被营养信息标志广告影响的合适的目标客户是一个具有挑战性的判断过程。相比之下,新媒体可

通信工程外文翻译---一点多址扩频通信系统的应用

【附录】 英文文献 The Application of one point Multiple Access Spread Spectrum Communication System Liu Jiangang, Nanyang City, HenanProvince Electric Power Industry Bureau 【ABSTRACT】Spread Spectrum Digital Microwave communication as a communication, because their excellent performance have been widely used. The article in Nanyang City Power Industry Bureau one point Multiple Access Spread Spectrum Communication System as an example.briefed the spread spectrum communications, the basic concept and characteristics of the power system communication applications .KEYWORDS:one point multiple access; Spread-spectrum communication; Attenuation Nanyang City in the outskirts of Central cloth 35 to 11 kv substation farm terminals, their operation management rights belong to the Council East, Rural Power Company west (the eastern suburb of agricultural management companies -- four, the western suburbs of Rural Power Company Management 7), Scheduling of the various stations of the means of communication to the original M-150 radio and telephone posts. 2002 With the transformation of rural network, the remote station equipment into operation and communication channels to put a higher demand .As PUC Dispatch Communication Building to the east and west of farmers -- the difference between a company linked to fiber, Therefore, if 11 substations and the establishment of a transfer Link Building links Point may be the data and voice were sent to two rural power companies dispatch room, Rural Network scheduling for the implementation of automation to create the necessary conditions. Given the status and power grid substation level, nature, taking into account the carrier and optical-fiber communications to conduct multiple forwarding, increasing the instability factor, considering the cost and conditions of the urban construction, Finally decided to adopt wireless spread-spectrum technology to establish that 11

数控激光加工的技术水平以及应用外文文献翻译、中英文翻译

英文文献 Numerical control laser processing technology and application Pick to: as the main symbol of science and Technology development in the 20th century and the modern information society one of the pillars of optoelectronic Technology, Laser Technology, Laser Technology) and the development of Laser industry attaches great importance to by the advanced countries in the world. Numerical control and integrated the Laser and the optical system of the computer numerical control technology, advanced and high precision and automation of the workpiece positioning, the combination of formation, development and production of machining center has become a Laser machining, Laser Processing) is an important trend of development. Key words: CNC; Laser machining, Laser Processing); Level; application Before: laser is regarded as one of the most important scientific discoveries of the twentieth century, as soon as it was caused the great attention of materials scientists. In November 1971, gm pioneered the use of a 250 w CO2 laser to improve wear resistance materials using laser radiation test and research, and in 1974 successfully completed automobile redirector shell

基于m序列的扩频通信系统的仿真设计外文翻译

扩频技术 摘要 扩频技术是信号(例如一个电气、电磁,或声信号)生成的特定带宽频率域中特意传播,从而导致更大带宽的信号的方法。这些技术用于各种原因包括增加抗自然干扰和干扰,以防止检测,并限制功率流密度(如在卫星下行链路)的安全通信设立的。频率跳变的历史: 跳频的概念最早是归档在1903年美国专利723188和美国专利725605由尼古拉特斯拉在1900年7月提出的。特斯拉想出了这个想法后,在1898年时展示了世界上第一个无线电遥控潜水船,却从“受到干扰,拦截,或者以任何方式干涉”发现无线信号控制船是安全的需要。他的专利涉及两个实现抗干扰能力根本不同的技术,实现这两个功能通过改变载波频率或其他专用特征的干扰免疫。第一次在为使控制电路发射机的工作,同时在两个或多个独立的频率和一个接收器,其中的每一个人发送频率调整,必须在作出回应。第二个技术使用由预定的方式更改传输的频率的一个编码轮控制的变频发送器。这些专利描述频率跳变和频分多路复用,以及电子与门逻辑电路的基本原则。 跳频在无线电报中也被无线电先驱约翰内斯Zenneck提及(1908,德语,英语翻译麦克劳希尔,1915年),虽然Zenneck自己指出德律风根在早几年已经试过它。Zenneck 的书是当时领先的文本,很可能后来的许多工程师已经注意到这个问题。一名波兰的工程师(Leonard Danilewicz),在1929年提出了这个想法。其他几个专利被带到了20世纪30年代包括威廉贝尔特耶斯(德国1929年,美国专利1869695,1932)。在第二次世界大战中,美国陆军通信兵发明一种称为SIGSALY的通信系统,使得罗斯福和丘吉尔之间能相互通信,这种系统称为扩频,但由于其高的机密性,SIGSALY的存在直到20世纪80年代才知道。 最著名的跳频发明是女演员海蒂拉玛和作曲家乔治安太尔,他们的“秘密通信系统”1942年获美国第2,292,387专利。拉玛与前夫弗里德里希汀曼德这位奥地利武器制造商在国防会议上了解到这一问题。安太尔-拉马尔版本的跳频用钢琴卷88个频率发生变化,其旨在使无线电导向鱼雷,让敌人很难来检测或干扰。该专利来自五零年代ITT公司和其他私人公司开始时发展码分多址(CDMA),一个民间形式扩频,尽管拉马尔专利有没对后续技术有直接影响。它其实是在麻省理工学院林肯实验室、乐华政府和电子工业公司、国际电话电报公司及万年电子系统导致早期扩频技术在20世纪50年代的长期军事研究。雷达系统的并行研究和一个称为“相位编码”的技术类似概念对扩频发展造成影响。

数控机床刀具设计论文中英文资料外文翻译文献综述

数控机床刀具设计 中英文资料 英语原文: Design Of Tool Machine Prop Research significance The original knife machine control procedures are designed individually, not used tool management system, features a single comparison, the knife only has to find the tool knife, knife positioning the shortest path, axis tool change, but does not support large-scale tool. Automatic knife in the knife election, in the computer memory knife-election on the basis of using the Siemens 840 D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its other machine. Automatic tool change systems will be faster growth, reduced tool change time, increase the positioning accuracy tool is an important means to help NC technology development. Tool and inventory components of modern production is an important link in the management, especially for large workshop D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its oth management. The traditional way of account management, and low efficiency, high error rate, and not sharing information and data, tools and the use of state can not track the life cycle, are unable to meet the current information management needs. With actual production, we have to establish a workshop tool for the three-dimensional tool storage system to meet the knife workshop with auxiliary storage and management needs. The system uses optimization technology, a large number of computer storage inventory information, timely, accurate, and comprehensive tool to reflect the inventory situation. The entire system uses a graphical interface, man-machine dialogue tips from the Chinese menu, select various functions can be realized and the importation of all kinds of information. Management system using online help function. Through the workshop management, network management and sharing of information. Have automated inventory management, warehousing management tool, a tool for the management and statistical functions. 1.System components and control structure The entire system, including the structure and electrical machinery control systems. 1.1.1Mechanical structure and working principle Tool from the stent, drive, drive system, Turret, shielding, control system, and electrical components. Support from the column, beam, the upper and lower guide Central track, and track support component.

相关文档
相关文档 最新文档