机械设计制造及其自动化外文翻译外文文献英文文献普通钻床改造为多轴钻床复习过程
普通钻床改造为多轴钻床
目前，我国中、小型企业的产品质量和生产效率都需要有一个新的提高,但是加工手段却远远不能满足需要,许多中小型企业都结合自己的实际对设备的技术状态进行改进，通过强化自身,以求自我发展普通钻床为单轴机床，但安装上多轴箱就会成为多轴的钻床，改造成多轴钻床后，能大大地缩短加工时间，提高生产效率。
多轴加工应用：据统计，一般在车间中普通机床的平均切削时间很少超过全部工作时间的15%。其余时间是看图、装卸工件、调换刀具、操作机床、测量以及清除铁屑等等。使用数控机床虽然能提高85%，但购置费用大。某些情况下，即使生产率高，但加工相同的零件，其成本不一定比普通机床低。故必须更多地缩短加工时间。不同的加工方法有不同的特点，就钻削加工而言，多轴加工是一种通过少量投资来提高生产率的有效措施。
多轴加工优势：虽然不可调式多轴头在自动线中早有应用，但只局限于大批量生产。即使采用可调式多轴头扩大了使用范围，仍然远不能满足批量小、孔型复杂的要求。尤其随着工业的发展，大型复杂的多轴加工更是引人注目。例如原子能发电站中大型冷凝器水冷壁管板有15000个ψ20孔，若以摇臂钻床加工，单单钻孔与锪沉头孔就要842.5小时，另外还要划线工时151.1小时。但若以数控八轴落地钻床加工，钻锪孔只要171.6小时，划线也简单，只要1.9小时。因此，利用数控控制的二个坐标轴，使刀具正确地对准加工位置，结合多轴加工不但可以扩大加工范围，而且在提高精度的基础上还能大大地提高工效，迅速地制造出原来不易加工的零件。有人分析大型高速柴油机30种箱形与杆形零件的2000多个钻孔操作中，有40%可以在自动更换主轴箱机床中用二轴、三轴或四轴多轴头加工，平均可减少20%的加工时间。1975年法国巴黎机床展览会也反映了多轴加工的使用愈来愈多这一趋势。
多轴加工的设备：多轴加工是在一次进给中同时加工许多孔或同时在许多相同或不同工
件上各加工一个孔。这不仅缩短切削时间，提高精度，减少装夹或定位时间，并且在数控机床中不必计算坐标，减少字块数而简化编程。它可以采用以下一些设备进行加工：立钻或摇臂钻上装多轴头、多轴钻床、多轴组合机床心及自动更换主轴箱机床。甚至可以通过二个能自动调节轴距的主轴或多轴箱，结合数控工作台纵横二个方向的运动，加工各种圆形或椭圆形孔组的一个或几个工序。现在就这方面的现状作一简介。
多轴头：从传动方式来说主要有齿轮传动与万向联轴节传动二种。这是大家所熟悉的。前者效率较高，结构简单，后者易于调整轴距。从结构来说有不可调式与可调式二种。前者轴距不能改变，多采用齿轮传动，仅适用于大批量生产。为了扩大其赞许适应性，发展了可调式多轴头，在一定范围内可调整轴距。它主要装在有万向.二种。（1）万向轴式也有二种:具有对准装置的主轴。主轴装在可调支架中，而可调支架能在壳体的T形槽中移动，并能在对准的位置以螺栓固定。（2）具有公差的圆柱形主轴套。主轴套固定在与式件孔型相同的模板中。前一种适用于批量小且孔组是规则分布的工件（如孔组分布在不同直径的圆周上）。后一种适用于批量较大式中小批量的轮番生产中，刚性较好，孔距精度亦高，但不同孔型需要不同的模板。多轴头可以装在立钻式摇臂钻床上，按钻床本身所具有的各种功能进行工作。这种多轴加工方法，由于钻孔效率、加工范围及精度的关系，使用范围有限。
多轴箱：也象多轴头那样作为标准部件生产。美国Secto公司标准齿轮箱、多轴箱等设计的不可调式多轴箱。有32种规格，加工面积从300Ｘ300毫米到600Ｘ1050毫米，工作轴达60根，动力达22.5千瓦。Romai工厂生产的可调多轴箱调整方便，只要先把齿轮调整到接近孔型的位置，然后把与它联接的可调轴移动到正确的位置。因此，这种结构只要改变模板，就能在一定范围内容易地改变孔型，并且可以达到比普通多轴箱更小的孔距。根据成组加工原理使用多轴箱或多轴头的组合机床很适用于大中批量生产。为了在加工中获得良好的效
果，必需考虑以下数点：（1）工件装夹简单，有足够的冷却液冲走铁屑。（2）夹具刚性好，加工时不形变，分度定位正确。（3）使用二组刀具的可能性，以便一组使用，另一组刃磨与调整，从而缩短换刀停机时间。（4）使用优质刀具，监视刀具是否变钝，钻头要机磨。（5）尺寸超差时能立即发现。
多轴钻床：这是一种能满足多轴加工要求的钻床。诸如导向、功率、进给、转速与加工范围等。巴黎展览会中展出的多轴钻床多具液压进给。其整个工作循坏如快进、工进与清除铁屑等都是自动进行。值得注意的是，多数具有单独的变速机构，这样可以适应某一组孔中不同孔径的加工需要。
(1) 自动更换主轴机床
自动更换主轴机床顶部是回转式主轴箱库，挂有多个不可调主轴箱。纵横配线盘予先编好工作程序，使相应的主轴箱进入加工工位，定位紧并与动力联接，然后装有工件的工作台转动到主轴箱下面，向上移动进行加工。当变更加工对象时，只要调换悬挂的主轴箱，就能适应不同孔型与不同工序的需要。
(2) 多轴转塔机床
转塔上装置多个不可调或万向联轴节主轴箱，转塔能自动转位，并对夹紧在回转工作台的工件作进给运动。通过工作台回转，可以加工工件的多个面。因为转塔不宜过大，故它的工位数一般不超过4—6个。且主轴箱也不宜过大。当加工对象的工序较多、尺寸较大时，就不如自动更换主轴箱机床合适，但它的结构简单。
(3) 自动更换主轴箱组合机床
它由自动线或组合机床中的标准部件组成。不可调多轴箱与动力箱按置在水平底座上，主轴箱库转动时整个装置紧固在进给系统的溜板上。主轴箱库转动与进给动作都按标准子程序工作。换主轴箱时间为几秒钟。工件夹紧于液压分度回转工作台，以便加工工件的各个面。好
果回转工作台配以卸料装置，就能合流水生产自动化。在可变生产系统中采用这种装置，并配以相应的控制器可以获得完整的加工系统。
(4) 数控八轴落地钻床
大型冷凝器的水冷壁管板的孔多达15000个，它与支撑板联接在一起加工。孔径为20毫米，孔深180毫米。采用具有内冷却管道的麻花钻，5－7巴压力的冷却液可直接进入切削区，有利于排屑。钻尖磨成90°供自动定心。它比普通麻花钻耐用，且进给量大。为了缩短加工时间，以8轴数控落地加工。
多轴加工趋势：多轴加工生产效率高，投资少，生产准备周期短，产品改型时设备损失少。而且随着我国数控技术的发展，多轴加工的范围一定会愈来愈广，加工效率也会不断提高。生产任务：在一批铸铁连接件上有同一个面上有多个孔加工。在普通立式钻床上进行孔加工，通常是一个孔一个孔的钻削，生产效率低，用非标设备，即组合机床加工，生产效率高，但设备投资大。但把一批普通立式普通单轴钻床改造为立式多轴钻床，改造后的多轴钻床，可以同时完成多个孔的钻、扩、铰、等工序。
General transformation of multi-axis drilling
machine drilling machin
At present, China's small and medium enterprises in product quality and production efficiency are the need for a new increase. But the processing means is far from sufficient. Many small and medium enterprises with their actual technical state of equipment improvements, through strengthening its own. In order to https://www.360docs.net/doc/ad1694698.html,mon drilling for single-axis machine tools, but the installation will become a multi-axis multi-axle box of the drill, transformation into a multi-axis drilling, we could greatly shorten the processing time, improve production efficiency.
Application of multi-axis machining ：According to statistics, in general machine tools in the workshop in general, the average cutting time rarely exceeds 15% of total working hours. The remaining time is plug-in, loading and unloading the workpiece, exchange tools, operation tools, measurements, and clear the iron filings and so forth. Although the use of CNC machine tools can improve 85%, but the purchase of costly. In some cases, even if the high productivity, but the processing of the same components, the cost is not necessarily lower than the average machine. Therefore must be more to shorten the processing time. Different processing methods have different characteristics, the drilling process, the multi-axis machining is a small investment to increase productivity through effective measures.
The advantages of multi-axis machining ：Although it is not the first in automatic multi-axis adjustable long line applications, but only limited to high-volume production. Even with the adjustable multi-axis head expanded the scope of use is still far from being able to meet the volume is small, hole complex requirements. In particular, as industrial development, large and complex multi-axis machining is even more compelling. For example, large-scale nuclear power plants in the water-wall tube plate condenser has 15000 ψ20 holes, if ra dial drilling machine processing, and simply drilling holes and countersink countersunk head is necessary to 842.5 hours, while also crossed hours 151.1 hours. However, if the 8-axis CNC machining floor drilling, drilling countersink holes as long as 171.6 hours, crossed is also simple, as long as 1.9 hours. Therefore, the use of numerical control of two axis, so that proper alignment tool processing location, combined with multi-axis machining can not only expand the range of processing, but also on the basis of improving the accuracy can greatly enhance the work efficiency, easy to quickly create original processing parts. Some analysis of large high-speed diesel engine with 30 kinds of box-shaped rod-shaped parts of the more than 2,000 drilling operations, 40% could be the automatic replacement of machines using two-axis spindle box, three-axis or four-axis multi-axis machining head, the average can be reduced 20% of the processing time. Machine Tool Exhibition in Paris in 1975 also reflected the multi-axis machining using more and more the trend.
Multi-axis machining equipment：Multi-axis machining is the same time in a feed processing a number of holes or simultaneously in many of the same or different processing of a workpiece on each hole. This will not only shorten the cutting time and improve accuracy, reduce fixturing or positioning time, and in the CNC machine tool is not
necessary to calculate the coordinates, reducing the number of character blocks and simplified programming. It can be processed using the following equipment: radial drilling vertical drilling, or upload multi-axis head, multi-axis drilling machine, multi-axis modular machine tool spindle box heart and automatic replacement of machines. May even be able to automatically adjust wheelbase by two or more of the spindle axle box, junction All CNC vertical and horizontal table two directions of movement, processing a variety of round or oval-shaped hole group of one or several steps. Now the status quo in this regard to make a profile.
Multi-Axis Head ：Transmission is from the main drive gear drive with two kinds of universal joint couplings. This is our familiar. Former is more efficient, simple structure, which is easy to adjust wheelbase. From the structure is concerned there is not adjustable and the adjustable two kinds. The former can not change the wheelbase, multi-use gear drive, only applies to high-volume production. Adaptability in order to expand its approval to develop a multi-axis adjustable head, in a certain range adjustable wheelbase. It is mainly mounted in a universal. Two. (1) there are two kinds of universal axis: alignment device with a spindle. Spindle mounted on adjustable bracket in an adjustable bracket can be T-shaped slot in the shell move, and the position in alignment with bolted. (2) with a tolerance of cylindrical spindle units. Set of fixed spindle hole with pieces of the same type template. The former applies to small batch and the rules of distribution of pore groups are artifacts (such as the hole groups in different diameter circle). The latter applies to a larger batch-type production of small quantities of turns, rigid better pitch accuracy is also high, but a different hole requires a different template.
Multi-axis head can be mounted on vertical drilling-type radial drilling machine, press the drill itself with the various functions work. This multi-axis processing methods, due to drilling efficiency, range and accuracy of processing of the relationship between the use of limited scope.
Multi-axle box ：As also the first multi-axis as the production as a standard component. U.S. Secto's standard gear boxes, multi-axle box, etc. are not designed adjustable multi-axle box. 32 kinds of specifications, process size from 300X300 mm to 600X1050 mm, the working-axis up to 60, and power up to 22.5 kilowatts. Romai factory adjustable multi-axle box easy to adjust, as long as the gear should first be adjusted to the location near the pass and then connected with its adjustable-axis move to the correct location. Therefore, this structure changes as long as the template, will be able to pass a certain extent change the content of shoes, and can reach more than ordinary axle box smaller pitch.
According to principles of the use of group processing the first multi-axle, or a combination of multi-axis machine tool is applicable to large and medium volume production. In order to process to get good results, need to consider the following points: (1) workpiece clamping simple, there is enough coolant away iron filings. (2) The fixture rigidity, processing, without deformation, dividing the right position. (3) the possibility of using the two group knives for a group to use, another set of grinding and adjustment, thereby reducing tool change downtime. (4) The use of quality tools to monitor whether the blunt tool, drill grinding to machine. (5) Dimensions can be detected immediately when the ultra-poor.
Multi-axis drilling machine ：This is a multi-axis machining to meet the requirements of the drill. Such as orientation, power, feed, speed and processing range. Displayed at the Paris Exhibition of multi-axis drilling machine with hydraulic multi-feed. Throughout its work, such as fast-forward through the bad, workers enter and clear the iron filings are all automatically. It is noteworthy that the majority of agencies with separate variable speed, so that one group can adapt to the different pore size hole processing needs. 1.2.4 automatic replacement machine tool spindle box
In order to rationalize the needs of small and medium volume production in recent years the development of the automatic replacement of modular machine tool spindle box. (1) The automatic replacement spindle machine
Automatic replacement of rotary spindle machine tool spindle box at the top is a library, there are several non-adjustable hanging spindle box. Vertical and horizontal patch panel to the first series of good working procedures, so that the corresponding spindle box into the processing station, location and with the power connection tight, and then turn to the table with the workpiece spindle box below, upward mobility for processing. When the change processing object, as long as the exchange suspension spindle box, you can pass with different processes for different needs.
(2) The multi-axis machine tool turret
Turret to install more non-adjustable or universal coupling spindle box, turret can automatically switch to digital, and clamp the workpiece in the rotary table to feed motion. Through the rotary table can be a number of workpiece surface. Because the turret not be too big, so it is generally not exceed the median of workers 4-6. And the spindle box is also not too large. When the machining process more objects, size larger, it should automatically replace the machine tool spindle box fit, but its simple structure.
(3) Automatic replacement of modular machine tool spindle box
It consists of automatic line or a combination of standard machine parts. Non-adjustable multi-axle box and power box by home base in the horizontal, the spindle rotates, the entire case library fastening device to the system in the slip into the board. Library Headstock rotation and feed movement is based on standard routines of work. Headstock time for a few seconds. Clamping the hydraulic sub-degree rotary table so that each workpiece surface. Good fruit rotary table accompanied by discharging device, we can co-flow production automation. In the variable production system using this device, accompanied by the corresponding controller can obtain a complete processing system.
(4) 8-axis CNC drill floor
Large condenser water wall tube plate holes as many as 15,000, which linked together with the support plate processing. Diameter of 20 mm, hole depth 180 mm. Used inside the cooling pipe has a twist drill ,5-7 bar pressure, coolant directly into the cutting area is conducive to chip removal. And ground into a 90 ° drill point for the self-centering. Durable than regular twist drill, and a large quantity of feed. To shorten the processing time to 8-axis CNC machining floor.
trends in multi-axis machining ：Multi-axis machining high production efficiency, low investment and production preparation cycle is short, product modification, when a small loss of equipment. And as China's CNC technology, the scope of multi-axis machining will become the broad, processing efficiency will be improved.
production tasks ：A group of cast-iron joints have the same surface processing with multiple holes. In the general processing of vertical holes on the drill, usually a hole a hole drilling, production efficiency is low, use non-standard equipment, that is, combination of machining, production efficiency is high, but the large investment in equipment. However, the number of common vertical drilling machine to transform ordinary single-axis vertical multi-axis drilling machine after transformation, multi-axis drilling machine can simultaneously perform multiple hole drilling, expansion, hinges, and other processes.
红外数据通信技术外文翻译文献
红外数据通信技术外文翻译文献(文档含中英文对照即英文原文和中文翻译) Infrared Remote Control System Abstract Red outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique, drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn, the baud rate be quick, point to point SSL, be free from electromagnetism thousand Raos
etc. characteristics, can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission, at short distance wireless deliver aspect to own very obvious of advantage. Along with red outside the data deliver a technique more and more mature, the cost descend, red outside the transceiver necessarily will get at the short distance communication realm more extensive of application. The purpose that design this system is transmit customer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplish customer’s operation demand. Keywords: Infrared dray；Code；Decoding；LM386；Red outside transceiver 1 Introduction 1.1 research the background and significance Infrared Data Communication Technology is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.
英文文献翻译
中等分辨率制备分离的 快速色谱技术 W. Clark Still,* Michael K a h n , and Abhijit Mitra Departm(7nt o/ Chemistry, Columbia Uniuersity,1Veu York, Neu; York 10027 ReceiLied January 26, 1978 我们希望找到一种简单的吸附色谱技术用于有机化合物的常规净化。这种技术是适于传统的有机物大规模制备分离，该技术需使用长柱色谱法。尽管这种技术得到的效果非常好，但是其需要消耗大量的时间，并且由于频带拖尾经常出现低复原率。当分离的样本剂量大于1或者2g时，这些问题显得更加突出。近年来，几种制备系统已经进行了改进，能将分离时间减少到1-3h，并允许各成分的分辨率ΔR f≥（使用薄层色谱分析进行分析）。在这些方法中，在我们的实验室中，媒介压力色谱法1和短柱色谱法2是最成功的。最近，我们发现一种可以将分离速度大幅度提升的技术，可用于反应产物的常规提纯，我们将这种技术称为急骤色谱法。虽然这种技术的分辨率只是中等（ΔR f≥），而且构建这个系统花费非常低，并且能在10-15min内分离重量在的样本。4 急骤色谱法是以空气压力驱动的混合介质压力以及短柱色谱法为基础，专门针对快速分离，介质压力以及短柱色谱已经进行了优化。优化实验是在一组标准条件5下进行的，优化实验使用苯甲醇作为样本，放在一个20mm*5in.的硅胶柱60内，使用Tracor 970紫外检测器监测圆柱的输出。分辨率通过持续时间（r）和峰宽（w,w/2）的比率进行测定的（Figure 1），结果如图2-4所示，图2-4分别放映分辨率随着硅胶颗粒大小、洗脱液流速和样本大小的变化。
机械设计设计外文文献翻译、中英文翻译、外文翻译
机械设计 摘要：机器是由机械装置和其它组件组成的。它是一种用来转换或传递能量的装置，例如：发动机、涡轮机、车辆、起重机、印刷机、洗衣机、照相机和摄影机等。许多原则和设计方法不但适用于机器的设计，也适用于非机器的设计。术语中的“机械装置设计”的含义要比“机械设计”的含义更为广泛一些，机械装置设计包括机械设计。在分析运动及设计结构时，要把产品外型以及以后的保养也要考虑在机械设计中。在机械工程领域中，以及其它工程领域中，所有这些都需要机械设备，比如：开关、凸轮、阀门、船舶以及搅拌机等。 关键词：设计流程设计规则机械设计 设计流程 设计开始之前就要想到机器的实际性，现存的机器需要在耐用性、效率、重量、速度，或者成本上得到改善。新的机器必需具有以前机器所能执行的功能。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不要受到任何约束。即使产生了许多不切实际的想法，也会在设计的早期，即在绘制图纸之前被改正掉。只有这样，才不致于阻断创新的思路。通常,还要提出几套设计方案，然后加以比较。很有可能在这个计划最后决定中,使用了某些不在计划之内的一些设想。 一般的当外型特点和组件部分的尺寸特点分析得透彻时，就可以全面的设计和分析。接着还要客观的分析机器性能的优越性，以及它的安全、重量、耐用性，并且竞争力的成本也要考虑在分析结果之内。每一个至关重要的部分要优化它的比例和尺寸，同时也要保持与其它组成部分相协调。 也要选择原材料和处理原材料的方法。通过力学原理来分析和实现这些重要的特性，如那些静态反应的能量和摩擦力的最佳利用，像动力惯性、加速动力和能量；包括弹性材料的强度、应力和刚度等材料的物理特性，以及流体润滑和驱动器的流体力学。设计的过程是重复和合作的过程，无论是正式或非正式的进行，对设计者来说每个阶段都很重要。 最后，以图样为设计的标准，并建立将来的模型。如果它的测试是符合事先要
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
通信工程项目毕业材料外文翻译
用于多跳认知无线电网络的分布式网络编码控制信道 Alfred Asterjadhi等著 1 前言 大多数电磁频谱由政府机构长期指定给公司或机构专门用于区域或国家地区。由于这种资源的静态分配，许可频谱的许多部分在许多时间和/或位置未使用或未被充分利用。另一方面，几种最近的无线技术在诸如IEEE802.11，蓝牙，Zigbee之类的非许可频段中运行，并且在一定程度上对WiMAX进行操作;这些技术已经看到这样的成功和扩散，他们正在访问的频谱- 主要是2.4 GHz ISM频段- 已经过度拥挤。为了为这些现有技术提供更多的频谱资源，并且允许替代和创新技术的潜在开发，最近已经提出允许被许可的设备（称为次要用户）访问那些许可的频谱资源，主要用户未被使用或零星地使用。这种方法通常被称为动态频谱接入（DSA），无线电设备发现和机会性利用未使用或未充分利用的频谱带的能力通常称为认知无线电（CR）技术。 DSA和CR最近都引起了无线通信和网络界的极大关注。通常设想两种主要应用。第一个是认知无线接入（CW A），根据该认知接入点，认知接入点负责识别未使用的许可频谱，并使用它来提供对次用户的接入。第二个应用是我们在这个技术中研究的应用，它是认知自组织网络（CAN），也就是使用 用于二级用户本身之间通信的无许可频谱，用于诸如点对点内容分发，环境监控，安全性等目的，灾难恢复情景通信，军事通信等等。 设计CAN系统比CW A有更多困难，主要有两个原因。第一是识别未使用的频谱。在CW A中，接入点的作用是连接到互联网，因此可以使用简单的策略来推断频谱可用性，例如查询频谱调节器在其地理位置的频谱可用性或直接与主用户协商频谱可用性或一些中间频谱经纪人另一方面，在CAN中，与频谱调节器或主要用户的缺乏直接通信需要二级用户能够使用检测技术自己识别未使用的频谱。第二个困难是辅助用户协调媒体访问目的。在CW A中存在接入点和通常所有二级用户直接与之通信（即，网络是单跳）的事实使得直接使用集中式媒体接入控制（MAC）解决方案，如时分多址（TDMA）或正交频分多址（OFDMA）。相反，预计CAN将跨越多跳，缺少集中控制器;而对于传统的单通道多跳自组织网络而言，这个问题的几个解决方案是已知的，因为假设我们处理允许设备访问的具有成
计算机网络-外文文献-外文翻译-英文文献-新技术的计算机网络
New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.
外文翻译中文
运作整合 供应链协作的首要问题是提高运作整合的程度。供应链协作课达到的好处，直接关系到捕捉效率之间的职能的企业，以及全国的企业，构成了国内或国际供应链。本章重点阐述的挑战，一体化管理，由研究为什么一体化创造价值，并通过详列的挑战，双方的企业集成和供应链整合。必不可少的供应链流程是确定的。注意的是，然后向信息技术提供，以方便集成化供应链规划。本章最后审查了定价。在最后的分析，定价的做法和政府是至关重要的供应链的连续性。 为什么整合创造价值 基本的优点与挑战的综合管理介绍了在第1章。进一步解释整合管理的重要性，有用的指出客户都至少有三个角度的价值。 传统的角度来看，价值是经济价值。第二个价值的角度来看，是市场价值。 实现双方经济和市场价值是很重要的客户。然而，越来越多的企业认识到商业上的成功也取决于第三个角度来看，价值，被称为关联性。 物流一体化目标 为实现物流一体化的供应链背景下，6个业务目标必须同时取得：（ 1 ）响应，（ 2 ）差额减少，（ 3 ）库存减少，（ 4 ）托运巩固，（ 5 ）质量，（ 6 ）生命周期支持。的相对重要性，每个直接关系到公司的物流战略。 响应 一公司的工作能力，以满足客户的要求，及时被称为反应。作为一再指出，信息技术是促进反应为基础的战略，允许业务的承诺被推迟到最后可能时间，其次是加速投放。实施对应策略服务，以减少库存承诺或部署在预期客户的需求。响应服务转向业务重点从预测未来的需求，以容纳顾客对快速订单到出货的基础上。理想的情况是，在一个负责任的系统中，库存是没有部署，直到客户承诺。支持这样的承诺，公司必须有物流的属性，库存的可用性和及时交付，一旦客户订单收到。 差异减少 所有经营领域的物流系统很容易受到差额。方差结果从未能履行任何预期的层面后勤业务不如预期。举例来说，毫不拖延地在客户订单处理，意想不到的干扰，以便选择，抵港货物损坏，在客户的位置，和/或未能提供在适当的位置上的时间，所有创造无计划的差异，在订单到交货周期。一个共同的解决办法，以保障对不利的差异是使用库存安全库存，以缓冲行动。这亦是共同使用的首选运输，以克服意想不到的差异延误交货计划。这种做法，鉴于其相关的成本高，可以尽量减少使用资讯科技，以维持积极的物流控制。向程度的差异是最小化，物流的生产力将提高。因此，差异减少，消除系统中断，是一个基本的目标，综合物流管理。 库存减少 要达到的目标，库存减少，一个综合物流系统必须控制资产的承诺，并把速度。资产的承诺，是财政的价值部署清单。把速度，反映了利率，这是充实库存随着时间的推移。高转率，再加上预期的库存供货，平均资产用于库存正在迅速而有效利用，这就是整体资产承诺支持一个综合运作减至最低。 库存能够而且确实方便可取的好处这是很重要的要请记住。库存是至关重要的实现规模经济，在制造业和采购。目的是要减少和管理存货，以尽可能最低的水平，同时实现整体供应链绩效的目标。
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
5G无线通信网络中英文对照外文翻译文献
5G无线通信网络中英文对照外文翻译文献(文档含英文原文和中文翻译)
翻译： 5G无线通信网络的蜂窝结构和关键技术 摘要 第四代无线通信系统已经或者即将在许多国家部署。然而，随着无线移动设备和服务的激增，仍然有一些挑战尤其是4G所不能容纳的，例如像频谱危机和高能量消耗。无线系统设计师们面临着满足新型无线应用对高数据速率和机动性要求的持续性增长的需求，因此他们已经开始研究被期望于2020年后就能部署的第五代无线系统。在这篇文章里面，我们提出一个有内门和外门情景之分的潜在的蜂窝结构，并且讨论了多种可行性关于5G无线通信系统的技术，比如大量的MIMO技术，节能通信，认知的广播网络和可见光通信。面临潜在技术的未知挑战也被讨论了。 介绍 信息通信技术（ICT）创新合理的使用对世界经济的提高变得越来越重要。无线通信网络在全球ICT战略中也许是最挑剔的元素，并且支撑着很多其他的行业，它是世界上成长最快最有活力的行业之一。欧洲移动天文台（EMO）报道2010年移动通信业总计税收1740亿欧元,从而超过了航空航天业和制药业。无线技术的发展大大提高了人们在商业运作和社交功能方面通信和生活的能力无线移动通信的显著成就表现在技术创新的快速步伐。从1991年二代移动通信系统(2G)的初次登场到2001年三代系统（3G）的首次起飞，无线移动网络已经实现了从一个纯粹的技术系统到一个能承载大量多媒体内容网络的转变。4G无线系统被设计出来用来满足IMT-A技术使用IP面向所有服务的需求。在4G系统中，先进的无线接口被用于正交频分复用技术（OFDM），多输入多输出系统（MIMO）和链路自适应技术。4G无线网络可支持数据速率可达1Gb/s的低流度，比如流动局域无线访问，还有速率高达100M/s的高流速，例如像移动访问。LTE系统和它的延伸系统LTE-A，作为实用的4G系统已经在全球于最近期或不久的将来部署。 然而，每年仍然有戏剧性增长数量的用户支持移动宽频带系统。越来越多的
变电站_外文翻译_外文文献_英文文献_变电站的综合概述
英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,
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
通信工程移动通信中英文对照外文翻译文献
中英文翻译 附件1：外文资料翻译译文 通用移动通信系统的回顾 1.1 UMTS网络架构 欧洲/日本的3G标准，被称为UMTS。 UMTS是一个在IMT-2000保护伞下的ITU-T 批准的许多标准之一。随着美国的CDMA2000标准的发展，它是目前占主导地位的标准，特别是运营商将cdmaOne部署为他们的2G技术。在写这本书时，日本是在3G 网络部署方面最先进的。三名现任运营商已经实施了三个不同的技术：J - PHONE 使用UMTS，KDDI拥有CDMA2000网络，最大的运营商NTT DoCoMo正在使用品牌的FOMA（自由多媒体接入）系统。 FOMA是基于原来的UMTS协议，而且更加的协调和标准化。 UMTS标准被定义为一个通过通用分组无线系统（GPRS）和全球演进的增强数据
技术（EDGE）从第二代GSM标准到UNTS的迁移，如图。这是一个广泛应用的基本原理，因为自2003年4月起，全球有超过847万GSM用户，占全球的移动用户数字的68％。重点是在保持尽可能多的GSM网络与新系统的操作。 我们现在在第三代（3G）的发展道路上，其中网络将支持所有类型的流量：语音，视频和数据，我们应该看到一个最终的爆炸在移动设备上的可用服务。此驱动技术是IP协议。现在，许多移动运营商在简称为2.5G的位置，伴随GPRS的部署，即将IP骨干网引入到移动核心网。在下图中，图2显示了一个在GPRS网络中的关键部件的概述，以及它是如何适应现有的GSM基础设施。 SGSN和GGSN之间的接口被称为Gn接口和使用GPRS隧道协议（GTP的，稍后讨论）。引进这种基础设施的首要原因是提供连接到外部分组网络如，Internet或企业Intranet。这使IP协议作为SGSN和GGSN之间的运输工具应用到网络。这使得数据服务，如移动设备上的电子邮件或浏览网页，用户被起诉基于数据流量，而不是时间连接基础上的数据量。3G网络和服务交付的主要标准是通用移动通信系统，或UMTS。首次部署的UMTS是发行'99架构，在下面的图3所示。 在这个网络中，主要的变化是在无线接入网络（RAN的）CDMA空中接口技术的引进，和在传输部分异步传输模式作为一种传输方式。这些变化已经引入，主要是为了支持在同一网络上的语音，视频和数据服务的运输。核心网络保持相对不变，主要是软件升级。然而，随着目前无线网络控制器使用IP与3G的GPRS业务支持节点进行通信，IP协议进一步应用到网络。 未来的进化步骤是第4版架构，如图4。在这里，GSM的核心被以语音IP技术为基础的IP网络基础设施取代。 海安的发展分为两个独立部分：媒体网关（MGW）和MSC服务器（MSS）的。这基本上是打破外连接的作用和连接控制。一个MSS可以处理多个MGW，使网络更具有扩展性。 因为现在有一些在3G网络的IP云，合并这些到一个IP或IP/ ATM骨干网是很有意义的（它很可能会提供两种选择运营商）。这使IP权利拓展到整个网络，一直到BTS(基站收发信台)。这被称为全IP网络，或推出五架构，如图五所示。在HLR/ VLR/VLR/EIR被推广和称为HLR的子系统（HSS）。 现在传统的电信交换的最后残余被删除，留下完全基于IP协议的网络运营，并