第一篇：专业英语PPT演讲稿
1、Lathe [leið]
2、Value of two yuan of the third series of the RMB ——the turner3、A lathe is a machine tool which rotates the workpiece on its axis to perform various ['vεəriəs] operations such as cutting, sanding(砂磨), knurling['nə:liŋ](滚花), drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry['simitri](对称)about an axis of rotation.（center lathe，vertical lathe）
4、History
The lathe is an ancient tool, dating at least to ancient Egypt ['i:dʒipt] and known and used in Assyria [ə'siriə] and ancient Greece [ɡri:s].The origin ['ɔridʒin, 'ɔ:-] of turning dates to around 1300 BC when the Ancient ['einʃənt] Egyptians [i:'dʒipʃənz] first developed a two-person lathe.（One person would turn the wood work piece with a rope while the other used a sharp tool to cut shapes in the wood.）Ancient Rome improved the Egyptian design with the addition of a turning bow.In the Middle Ages a pedal replaced hand-operated turning,（freeing both the craftsman's hands to hold the woodturning tools.The pedal was usually connected to a pole, often a straight-grained sapling.）The system today is called the “spring pole” lathe.Spring pole lathes were in common use into the early 20th century.During the Industrial Revolution, mechanized ['mekənaizd] power generated by water wheels or steam engines was transmitted to the lathe via line shafting,(allowing faster and easier work.Metalworking lathes evolved into heavier machines with thicker, more rigid parts.)Between the late 19th and mid-20th centuries, individual electric motors ['məutə] at each lathe replaced line shafting as the power source.Beginning in the 1950s, servomechanism[,sə:vəu'mekənizəm, 'sə:vəu,me-](伺服机构)were applied to the control of lathes and other machine tools via numerical control,(which often was coupled with computers to yield computerized numerical control.)Today manually controlled and CNC lathes coexist（共存）in the manufacturing industries ['indəstri].5、Description：Parts
Explanation of the standard components of most lathes:
• Bed床身: Usually made of cast iron.Provides a heavy rigid frame on which all the main components are mounted.• Ways床身导轨: Inner and outer guide rails that are precision machined parallel to assure accuracy of movement.• Headstock['hedstɔk]床头箱，主轴箱: mounted in a fixed position on the inner ways, usually at the left end.Using a chuck, it rotates the work.• Gearbox ①齿轮箱②变速器: inside the headstock, providing multiple speeds with
a geometric ratio by moving levers.• Spindle['spindl]心轴，主轴: Hole through the headstock to which bar stock can be fed, which allows shafts that are up to 2 times the length between lathe centers to be worked on one end at a time.• Chuck卡盘: 3-jaw(self centering)or 4-jaw(independent)to clamp part being machined.• Chuck: allows the mounting of difficult workpieces that are not round, square or triangular.• Tailstock尾架: Fits on the inner ways of the bed and can slide towards any position the headstock to fit the length of the work piece.An optional taper turning attachment would be mounted to it.• Tailstock Quill[kwil]尾架套管: Has a Morse taper to hold a lathe center, drill bit or other tool.• Carriage托架，滑动架: Moves on the outer ways.Used for mounting and moving most the cutting tools.• Cross Slide横刀架，横拖板，横溜板: Mounted on the traverse slide of the carriage, and uses a handwheel to feed tools into the workpiece.• Tool Post刀架，刀座: To mount tool holders in which the cutting bits are clamped.• Compound Rest复式刀架: Mounted to the cross slide, it pivots around the tool post.• Apron['eiprən]床鞍: Attached to the front of the carriage, it has the mechanism and controls for moving the carriage and cross slide.• Feed Rod进给杆: Has a keyway, with two reversing pinion gears, either of which can be meshed with the mating bevel gear to forward or reverse the carriage using a clutch.• Lead Screw丝杠: For cutting threads.• Split Nut开合螺母: When closed around the lead screw, the carriage is driven along by direct drive without using a clutch.• Quick Change Gearbox快换齿轮箱: Controls the movement of the carriage using levers.• Steady Rest固定中心架: Clamped to the lathe ways, it uses adjustable fingers to contact the workpiece and align it.Can be used in place of tailstock or in the middle to support long or unstable parts being machined.• Follow Rest跟刀架: Bolted to the lathe carriage, it uses adjustable fingers to bear against the workpiece opposite the cutting tool to prevent deflection.6~
9、Description：accessories [ək'sesəri]
three-jaw [dʒɔ:] chuck [tʃʌk]: Self-centering three-jaw chuck and key with one jaw removed and inverted showing the teeth that engage in the scroll plate.The scroll plate is rotated within the chuck body by the key, the scroll engages the teeth on the underside of the jaws which moves the three jaws in unison, to tighten or release the workpiece.four-jaw chuck :Independent four-jaw chuck, also known as a universal chuck, with the jaws independently set.The key is used to adjust each jaw separately.Collet弹性夹头: A collet ['kɔlit] is a holding device—specifically, a subtype of chuck—that forms a collar around the object to be held and exerts a strong clamping force on the object when it is tightened, usually by means of a tapered outer collar.It may be used to hold a workpiece or a tool.Faceplate花盘: A lathe faceplate is the basic workholding accessory for a wood or metal turning lathe.It is a circular metal(usually cast iron)plate which fixes to the end of the lathe spindle.The workpiece is then clamped to the faceplate, typically using t-nuts in slots in the faceplate, or less commonly threaded holes in the faceplate itself.dead center死顶尖: Dead center(The conical piece)mounted in the spindle of a lathe and being used to support a workpiece being driven by a carrier setup live center活顶尖:A live center or revolving center is constructed so that the 60° center runs in its own bearings and is used at the non-driven or tailstock end of a machine.[2] It allows higher turning speeds without the need for separate lubrication [,lu:bri'keiʃən], and also greater clamping pressures.lathe carrier['kæriə]车床鸡心夹头: A lathe dog, also known as a lathe carrier, is a device that clamps around the workpiece and allows the rotary motion of the machine's spindle to be transmitted to the workpiece.Mandrel['mændrəl]心轴: an object used to shape machined work.10、application
Lathes are used in woodturning, metalworking, metal spinning（旋压）, and glass-working.Lathes can be used to shape pottery, the best-known design being the potter's wheel陶车.Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces and screw threads or helices.Ornamental [,ɔ:nə'mentəl] lathes can produce three-dimensional solids（实体）of incredible complexity11、Examples of work produced from a lathe12、thank you!
I`m very happy to have this opptunity to give you a talk.today,my topic is lathe.I know many of you are familiar with this topic
Can you hear me clearly?
I think ti would be best to start out by looking at the picture on the screen
I would like to talk about first is the definition of the lathe
question ['kwestʃən]
that is all,thank you very much
do you have any questions? please show me your hand.Who else?
I think we have time for just one more question
第二篇：专业英语ppt底稿
智能光网络 由于ASON(智能光网络)是构造在各种传送技术之上的，也就是在传送平面SDH、光传送网(OTN)之上增加了独立控制平面，因此它支持目前传送网可以提供的各种速率和不同信号特性(如格式、比特率等)的业务。ASON网络可以在两个客户网元之间提供具有固定带宽的传输通道，通道界定在光网络的输入接入点和输出接入点之间。
1.业务类型
ASON业务有以下几个方面：
SDH业务，支持G.707定义的SDH连接颗粒VC-n和VC-n-Xv； OTN业务，支持G.709定义的OTN连接颗粒ODUk和ODUk-n-Xv； 透明或不透明的光波长业务；
10Mb/s、100Mb/s、1Gb/s和10Gb/s的以太网业务；
基于光纤连接(FICON)、企业系统连接(ESCON)和光纤通道(FC)的存储域网络(SAN)业务。
ASON对新业务类型具有可扩展性。ASON可以支持多种类型的业务模型，每种业务模型都有自身的业务属性、目标市场和业务管理需求。
2..业务连接拓扑类型
为了支持增强型业务(如带宽按需分配、多样性电路指配和捆绑连接等)，ASON应支持呼叫和连接控制的分离。呼叫和连接控制的分离可以减少中间连接控制节点过多的呼叫控制信息，去掉解码和解释消息的沉重负担。ASON支持的连接拓扑类型包括：双向点到点连接、单向点到点连接、单向点到多点连接。
由于呼叫和连接分离，一个呼叫可以对应多个连接，目前双向点到点连接是最主要连接方式
3.业务连接类型
ASON网络支持3种业务网络连接类型：永久连接(PC)、交换连接(SC)、软永久连接(SPC)。
PC和SPC连接都是由管理平面发起的对连接的管理。PC和SPC的区别在于光网络内建立连接是利用网管命令还是实时信令，这两种方式都是由运营商发起建立的业务连接。SC连接通过UNI信令接口发起，用户的业务请求通过控制平面(包括信令代理)的UNI发送给运营商，即由用户直接发起建立业务连接。
业务等级
目前的传输网不能按照服务等级制订相应的资费政策，造成资源配置的浪费，而ASON网络可以方便地对业务电路的优先级进行划分，从而提供有服务品质协议(SLA)的传输业务电路。客户对不同连接的可靠性有不同的要求，这些要求可以采用“业务等级”来表述。在ASON网络中，业务等级主要是通过映射到不同恢复、保护选项和相关连接的优先级来实现的，例如建立优先级、保持优先级(是否可以预空闲)、恢复优先级。
建立优先级主要是指业务的建立响应时间，分别为在日、小时或分钟内建立业务连接。保持优先级(是否可以预空闲)主要是指在出现其他系统故障时系统是否会被空闲出来承载更重要的业务，业务连接本身有没有保护。
恢复优先级则是考虑系统出现故障时的恢复时间和恢复等级(如恢复业务百分比)。将单个业务等级映射到一系列保护、恢复选项，每个运营商有着不同的选择。控制层面支持基于每个连接链路优先级的设定，并支持将带宽资源预留作为恢复目的和失效修复后路由归一化。一般支持的业务连接等级包括：专用连接(1+1和1：1)、共享保护(1：N和M：N)、不保护(在主用电路上传送)、不保护业务(在保护电路上传送)等。
业务接入方法
为了将业务接入ASON网络，用户首先需要在传送平面上与运营商网络建立物理连接。按照运营商网络与客户的位置，业务接入可以采取局内接入(光网络网元与客户端网元在一地)、直接远端接入(具有专用链路连接到用户端)、经由接入子网的远端接入以及双归接入。
ASON必须支持双归接入方式。对于相同的客户设备采用双归接入时不应需要多个地址，双归接入是接入的一种特殊情况。采用双归接入的主要目的是增强网络的生存性，当一个接入失败时，客户的业务能够依靠另一个接入而不会中断。客户设备可以以双归的方式(两条不同的路径)接入到核心网/运营商。
从安全角度，网络资源应该避免没有授权的接入，业务接入控制就是限制和控制实体企图接入到网络资源的机制，特别是通过UNI和外部网络节点接口(E-NNI)。连接接纳控制(CAC)功能应支持以下安全特征。
1.CAC适用于所有通过UNI(或者E-NNI)接入到网络资源的实体。CAC包括实体认证功能，以防止冒充者通过假装另一个实体欺骗性地使用网络资源。已经认证了的实体将根据可配置的策略管理被赋予一个业务接入等级。
2.UNI和网络节点接口(NNI)上应提供机制来保证客户认证和链路信息完整性，如链路建立、拆除和信令信息，以用来连接管理和防止业务入侵。UNI和E-NNI还应包括基于CAC的应用计费信息，防止连接管理信息的伪造。
3.每个实体可以通过运营者管理策略的授权利用网络资源。
第三篇：专业英语演讲稿
feet, the carriers of life
good morning, ladies and gentlemen.i would like to tell you about an unusual assignment.i was surprised and amused when our teacher told us our homework was to wash our feet carefully.yeah, washing the feet is such a common daily activity that i’ve never paid much attention to it.my feet had been cooperating and helping each other, nearly always managing to get washed, while i was enjoying my readings.but that night, while i gently touched my feet in the hot water, i realized how nice and cozy bathing my feet could be.deep in my mind, the hands always seemed superior to the feet.people use all sorts of things from soap to moisture cream to protect their hands.the feet become, kind of, neglected, since the feet spend all day long with the ground and dirt, and quite inevitably, get really smelly.as i slowly soaped and rinsed my feet, i was beginning to understand why my teacher launched such a mission.she wanted us to realize that the feet were more helpful than we had ever imagined.surely, the hands are important.however it’s the feet that carry your whole body weight, and everything about your life.the feet carry you, as well as your hopes and dreams, and walk steadily upon the most solid ground, moving forward step by step, upon mountains and down valleys, over the smooth as well as the rough, through the bitterness as well as the joy.as i was washing my feet, i let my mind wander.i felt as if i was on a vast desert.looking around, i saw millions of footprints, large and small, deep and shallow, being the marks of existence, and the traces of life.and there i was, using my own feet, making my own path, towards the oasis of life……
thank you.脚，生命的载体
女士们，先生们，上午好!
我想告诉大家一份不寻常的家庭作业，老师布置我们当晚回家认真给自己洗一遍脚，听到后，我感到惊奇而有趣。
是啊，脚，我每晚必洗，但从未重视过。洗脚时，我津津有味地看着书，任双脚摩挲，互帮互助。但今晚，当我的双手触摸到自己的双脚时，是多么的舒服、惬意啊!
心中，总是觉得手比脚高贵，人们用香皂洗手，并抹上护手霜，百般呵护;而脚踩在地上，即使有鞋袜，也总被认为是与灰土打交道的粗笨一族，并有不可避免的异味，脚，似乎成了身体中被忽视的部分。
我仔细地洗着脚，渐渐地，我明白了老师的用意：她布置这个特殊的任务，是为了让我们认识到脚，其实比我们想象的更伟大。
无可争议，手固然重要。可脚却承担着你生命的全部重量。
脚，负着你，你沉甸甸的希望和梦想，踩着踏实的大地，一步一步地前进，走上了高山也走下了峡谷，走过了平坦也走过了崎岖，走过了苦难也走过了幸福。
我在洗脚，手脚依偎，恍惚间，我仿佛置身于广袤的大漠中。环视四周，一串串大大小小深深浅浅的脚印，这是存在的证明，生命的印迹。而我用自己的双脚，开辟着自己的道路，向生命的绿洲前进……
谢谢!
第四篇：专业英语演讲稿
feet, the carriers of life
good morning, ladies and gentlemen.i would like to tell you about an unusual assignment.i was surprised and amused when our teacher told us our homework was to wash our feet carefully.yeah, washing the feet is such a common daily activity that i’ve never paid much attention to it.my feet had been cooperating and helping each other, nearly always managing to get washed, while i was enjoying my readings.but that night, while i gently touched my feet in the hot water, i realized how nice and cozy bathing my feet could be.deep in my mind, the hands always seemed superior to the feet.people use all sorts of things from soap to moisture cream to protect their hands.the feet become, kind of, neglected, since the feet spend all day long with the ground and dirt, and quite inevitably, get really smelly.as i slowly soaped and rinsed my feet, i was beginning to understand why my teacher launched such a mission.she wanted us to realize that the feet were more helpful than we had ever imagined.
www.xiexiebang.com【xiexiebang.com范文网】
surely, the hands are important.however it’s the feet that carry your whole body weight, and everything about your life.the feet carry you, as well as your hopes and dreams, and walk steadily upon the most solid ground, moving forward step by step, upon mountains and down valleys, over the smooth as well as the rough, through the bitterness as well as the joy.as i was washing my feet, i let my mind wander.i felt as if i was on a vast desert.looking around, i saw millions of footprints, large and small, deep and shallow, being the marks of existence, and the traces of life.and there i was, using my own feet, making my own path, towards the oasis of life……
thank you.脚，生命的载体
女士们，先生们，上午好!
我想告诉大家一份不寻常的家庭作业，老师布置我们当晚回家认真给自己洗一遍脚，听到后，我感到惊奇而有趣。
是啊，脚，我每晚必洗，但从未重视过。洗脚时，我津津有味地看着书，任双脚摩挲，互帮互助。但今晚，当我的双手触摸到自己的双脚时，是多么的舒服、惬意啊!
心中，总是觉得手比脚高贵，人们用香皂洗手，并抹上护手霜，百般呵护;而脚踩在地上，即使有鞋袜，也总被认为是与灰土打交道的粗笨一族，并有不可避免的异味，脚，似乎成了身体中被忽视的部分。
我仔细地洗着脚，渐渐地，我明白了老师的用意：她布置这个特殊的任务，是为了让我们认识到脚，其实比我们想象的更伟大。
无可争议，手固然重要。可脚却承担着你生命的全部重量。
脚，负着你，你沉甸甸的希望和梦想，踩着踏实的大地，一步一步地前进，走上了高山也走下了峡谷，走过了平坦也走过了崎岖，走过了苦难也走过了幸福。
第五篇：专业英语演讲稿
英国教育体制简介
ladies and gentlemen: today i want to talk something about british education system.英国是一个有悠久教育传统的国家。它的教育体系经过几百年的沿革，相当的完善和复杂，且具有非常大的灵活性。可大致分为四个部分：学龄前教育、学校教育（义务教育）、延续教育、高等教育。第一部分：学龄前教育，即幼儿园教育。一般是为5岁以下的儿童开设的，没有具体的教学，目的是使他们在读小学时更能适应学校生活。
第二部分：义务教育.1-6年级为一个档次，其实就是幼儿园的等级，所以并没有具体的教学。7-9年级为一个档次。与我国小学类似，开始学习所有科目，但并不非常注重学习成绩，算是一种开导式教育以培养兴趣，故基础教育扎实度与国内不可相比。10-11年级被称为gcse,类似我国的初中。此时已经开始注重学生自己的兴趣培养，除了语文（英语），数学，外语（法语）之外，必修的为物理、生物、化学、电脑、体育。其他按照自己兴趣，选修三门科目。其范围非常广泛，美术、音乐、地理、拉丁、德语、体育理论、商业、经济等。所以学生可以不用为自己之前所不擅长的课再担心了。gcse在英国也称第四级和第五级，中国学生进入该课程的年龄为14-15岁，此为两年的一贯课程科，在上gcse可趁第二年的五月份时会有一次英国gcse课程国家大会考。英国学生完成gcse离开学校后可直接进入就业市场，想升大学者就会继续修读第六级的a-level课程。
第三部分：延续教育。16岁到大学前的教育。这是英国教育体系中最有特色也最精彩的部分，它是继小学中学教育之后的第三级教育。为进入高等教育或者就业打下基础。它分为两种体系：学业路线和职业路线。学业路线着重于培养学术研究方面的人才，职业路线则结合社会各层面的职业需要，培养在各种行业中具有专门技能知识的人才。
1、学业路线。a-level的全称是“普通教育高级证书”，是学业路线的重要阶段，学制一般为两年。它总共有100多个科目，专业分科极为细致，它不像我国学生在高中学习的课程。而更像是大学的基础课，相当于中国大学本科课程的首两年。as-level是a-level课程的一个特别组成部分，一门as-level科目在内容和分量上相当于一门a-level科目的一半，深度和难度上与a-level相当。a-level课程的学生第一年都将从as-level科目开始学习，所有学生必须选修四门以上不同的as-level科目。而在第二年再确定只选三门a-level科目。
2、职业路线。英国的职业教育可谓丰富多彩，从美容师到平面美术设计师、从婴儿护理到飞机维修师应有尽有。英国的职业教育与学业路线有一定的对应性，学生可以根据自己的学业情况选择进入学业路线的不同阶段。这种方式给学生提供了更多的选择机会，使不同类型的学生能够充分发挥自己的优势和潜能。gnvq国家通用职业文凭。它是一种广泛的职业教育课程，与学业路线中的gcse和a-level相平行，但在学业深度和难度上并不亚于这类课程。它的学习的方式灵活多样，学生可以根据自己的需要和兴趣爱好安排课程，选择学分制或模块式的学习方式，甚至可以在学习的过程中穿插工作，在学习和工作同时进行的过程中最终选择自己最喜欢的事业。gnvq的选科比较简单，每门课程就是一个专业，所有受到许多英国学生和中国留学生的青睐。
第四部分：高等教育。顾名思义，高等教育是英国教育体系中的高级阶段，它包括: 本科(bachelor degree)英国本科学士学位学制一般为三年，但有些大学的某些特殊专业要求读四年或以上，如牙科。在英国人眼中，医科和法律专业是最难考取也是最难读的专业。因为这两种学科的共同点是“人命关天”。研究生(master degree)英国的研究生课程只需要一年时间，这与中国和美国都不同。在这一年里学生主要是写论文和做课题研究，课堂教学较少，因此其他国家的留学生如果没有在英国经过一段时间的学习或语言不过关，是很难完成这一年课程的。高级国家文凭(hnd-higher national diploma)。hnd也是一种非常有用的文凭。它是职业教育体系中的最高阶段，学制一般为两年。hnd理论上相当于中国的大专文凭，但分类更细，专业性更强。进入hnd要求已经完成a-level或者gnvq-advanced的课程，中国的高中学生如果在某些方面（比如计算机）有特殊专长并且表现出相当好的语言能力的话，也有可能直接进入hnd，但读起来会相当辛苦。hnd毕业后，如果取得比较好的成绩，可以选择直接进入本科第三年的课程，通常是本校或联校的相应专业。也就是说，再加一年就可以取得学士学位。但英国最好的大学一般不接受此类学生。
大学每学年分为了3学期。第一学期为9月中至圣诞节（约12月中）；第二学期为1月中至万圣节（约4月中）；第三学期为5月初。教学段是第一和第二学期，第三学期属于考试。ucas 是大学院校入学委员会，为想至英国修读大学课程的学生提供申请入学服务。对336所大学院校之申请，皆必须通过ucas，学生并不能自己向学校直接申请。ucas有一点类似中国的大学高考，两者最大的不同是高考需要经由联考，而ucas只是申请。经由ucas需填写一份申请表(ucas form)，表格内可填写6个大学，亦即最多可同时向六所大学提出申请，也可以只申请一所大学。ucas form上六所大学排列的顺序不是学生选择的优先级，优先次序是在学生收到大学的offer letter后自行决定。篇二：专业英语演讲稿 part 1 the introduction of rose garden for centuries, there are many fairy tale about rose or take place in the rose garden, such as[the nightingale and the rose],you must heard of it, the nightingale made a red rose for the young man with her own blood with singing all night, it’s a sad story.what’s more, the story[wild swan],at the end of the story, princess sat on the rose blush with her swan brothers, what a romantic picture.today, as far as i am concerned, many girls must have a dream of having a wedding with plenty of roses, or being a beautiful bride like a fresh rose, what’s more, living in a rose garden with the beloved one and so on.in a conclusion, rose is a symbol of beauty and love, it express the best wish of having a romantic life and the emotion.here is a brief introduction of rose, it is a woody perennial of the genus rosa.there are more than 100 species in the world, gardeners plant them to build a rose garden.so now, i’ll leave the stage to my partner cai jun, she will tell us something about instance analysis.part 2 instance analysis ok this part, i will give an example to discuss the rose garden.first, it’s a brief introduction about qinghai rose garden it is part of low density and top housing estate, with large space occupation, simple style of england in qinghai.meanwhile, rose garden has high collectable, attract the crows admire and form a senic spot.in addition drive more and more people purchase it, promote the local economic growth.however, everything has two sides.rose garden not only increase the project costing unintentionally, but also has high requirements of the geographical conditions.and high price to limit consumers.that’s all what i want to say.part 3 the layout of rose garden the layout of rose garden contains four parts: pergola, lattice well, flowers hedge and others.(i draw some pictures to help us to understand it.)pergola: first, plant rose from both sides of pergola;then, lead the branch grows with it.lattice well: this is the iron wire.iron wire is utilized to make reticulation.the green stems could be coiled around the iron wire.lattice well will be done about three years.flowers hedge: there is a same way as the pergola to make a hedge.others: you can also use roses to make some animal shapes.such as: rabbit, hippocampus„„ the rose garden is done after collocate with garden lights, furniture, lattice well, flower hedge, pergola and awning.you can have a barbecue in the rose garden with friends.part 4 the most popular rose good evening, everyone, tonight id like to say something about the most popular rose.as we all known ,there are many kinds of roses, the red rose, blue rose, white rose, green roses and purple rose, black rose, yellow rose, rainbow rose.now, lets take a look some the most popular roses.look at the picture ,it called blue enchantress.we can rarely see a natural blue rose, when a white rose quickly to the flowering, watering it with dyes, because absorbs the dyes, and finally it turned blue blue enchantress means pure love and sincere love.this is roasted rose, roasted rose can adaptation for climate to grow in many country, it can be widely used in rose’s deep processing.it’s a rare superior varieties of agricultural then, champagne roses: champagne roses is the national flower of bulgaria.some people say wishing on a champagne roses can be achieved, so it called happy flower.corolla: corolla rose is the patent product of the united states, belong to the top varieties of red roses bulgaria rose: part 5 other five popular rose.blue moon, sweet pretty, alba meialandina, horatio nelson and sun sprinkles are also very popular among people.blue line rose have a fresh color like lavender, charming and make your feel romantic.it is popular in northern city and easily survival.sweet pretty it has a little of petals but has a number of flowers and like the butterflies dancing on the green leaves.you can see the stamen very clearly and the twigs are soft.alba meialandina the white color looks simple but elegant.it can serve as the potted plant and bedding plant.horatio nelson it cultivates from england.both cold-consistence and disease-consistence are very good.it can use to decorate the wood-fence and act as the cut flower.sun sprinkles these flowers have thin petals, but have long flowering phase.the color of flowers like the sunlight, let us feel warm.people often use to decorate the arch.the most popular rose part 6 today i will introduce five methods of growing roses;seedling、cuttage、grafting、marcottage and root division.cuttage twig cottage: choose the sprout buds in early spring, disbranch few xylom from stem, deal with growth hormone then insert nursery beds.stiff wood cottage: cut the substantial branch overwintering place in low temperature romm and insert upside down wet sand.next spring transplant to nursery beds.stiff wood hygroscopic: choose the branch with one or two leaves, cut the bottom, stick in the water, put it in 15℃—20℃ with sunshine, it can promote proliferate.grafting include budding、branch grafting and root grafting.there are two ways to marcottage, one is on the ground, the other one in the air.during the rose growing time, carve branch, curve it cover wet soil, when the wound outgrow new root, cut down and transplant.the second method we can choose a suitable position on train rose carve branch or peel off the skin.put a packet of soil around it about a month, cut down when it have root.the last one is root division.plant the roses deeply, urge branch grow root, cut the new root with the lateral branch to get a new one.here are the five kinds of planting roses, thank you for your attention.part 7 how to control diseases and insect pests there are often two kinds of diseases infect rose, powdery mildew and downy mildew.the powdery mildew often appears in new leaves in early spring and late autumn.it’s a kind of spore flow with the air.spraying water frequently can prevent the disease.and the infected leaves must be cut immediately once the rose was ill.the downy mildew will hurt the leaves, petals, shoots, pedicels.the humidity should be controlled under 85% to prevent downy mildew and don’t use too much nitrogenous fertilizer to prevent the disease.and there are two kinds of insect pests often hurt rose, aphid and red spider.aphid can appear in any time during a year.it will be threaten when weather is dry.pesticide should be sprayed in the growing point and back of leaves to control the pest.red spider will suck up chlorophyll of leaves.and pesticide should be sprayed at the early stage of the illness.篇三：专业英语演讲稿 introduction [?s?:kit]utilizing [?ju:tilaiz] operational amplifiers.运算放大器是一个非常有效和通用设备。它的应用范围广泛的电子工业，信号调理，专项转移功能，模拟仪表，模拟计算，及特殊系统设计的灌装要求。简单性和精确度是使用运算放大器的模拟电路特点 the feedback technique the precision and flexibility of the operational amplifier is a direct result of the use of negative feedback.generally speaking, amplifiers employing feedback will have superior operating characteristics at a sacrifice [?s?krifais]of gain.在运算放大器的精度和灵活性是利用负反馈的直接结果。一般来说，采用反馈的放大器有卓越的经营特点，在牺牲增益的代价下。
有了足够的反馈，闭环放大器的特点成为一个功能的反馈元件。在典型的反馈电路中，图1中，反馈元件是两个电阻器。的精度的“闭环”的增益设置的两个电阻的比率实际上是独立的“开环”放大器。因此，放大到几乎任何的精确度，可以容易地实现。notation符号 ?= symbol(a)is a buffer [?b?f?] 缓冲器 op工作 amp放大器 ?= symbol(c)is a differential input, differential output op amp.the outputs can be thought of as “inverting” [in?v?:t] 反转and “non-inverting”, and are shown across from [k?m?pli:??n] 完成of feedback loops on schematics [ski:?m?t?k].符号（a）是一个缓冲器的运算放大器 ?=符号（b）是一个差分输入，单端输出的运算放大器。这个符号代表最常见的类型，包括电压反馈和电流反馈运算放大器。它通常是在顶部和在底部的倒相输入端与非反相输入描绘的时间。?=符号（c）是差分输入，差分输出运算放大器。输出可以被认为是“反转”和“非反相”，并示出从相反的极性的输入对面容易完成的反馈回路原理图 power connections电源连接 power is supplied to each of these units at connections as shown in figure 4.such a connection is implied in all operational amplifier circuits.the dual [?dju:?l]两部分
电源供给到这些单元中的每一个，如在图4中所示的连接。这样的连接是隐含在所有的运算放大器电路。双电源呈现相同的绝对电压值从任一侧接地，而中心连接最终定义的公共线和接地电位。例外情况是可以使用单个电源的ac放大器电路。这是通过创建一个浮动的ac地面的隔直流电容器。在这种电路中，“半电源”的来源创建一个“虚拟地”正好有一半之间的正电源和接地电位的方法。electrical circuit models电气电路模型 the simplified models of the differential [?d?f??ren??l] 差分input operational amplifiers are shown in figures 6 and 7.在图6和图7中示出的差分输入运算放大器的简化模型。as indicated in figure 6, the operational amplifier can be represented by an ideal voltage source whose value depends on the input voltage appearing across the inverting and non-inverting inputs plus the effects of finite [?fainait] 有限input and output impedances [im?pi:d?ns]阻抗.the value, a, is known as the open loop(without feedback)gain of the operational amplifier.正如在图6中所示，运算放大器可以表示为一个理想电压源，其值取决于对输入电压的两端出现的反相和非反相输入端加上有限的输入和输出阻抗的影响。值，a，是被称为在运算放大器的开环增益（没有反馈）。the simplified model of the differential output operational amplifier(figure 7)is an accurate [??kjurit] approximation [??pr?ks??me???n]近似值only under special conditions of feedback(see “balanced amplifier” later in this handbook).figure 6 represents the model of the differential output type when it is used as a single ended output device;the inverting output simply being ignored.简化模型的差分输出运算放大器（图7）是一个准确近似，仅在特殊条件下的反馈（见“平衡放大器”，在本手册后面）。图6表示的差分输出的模型类型时，它被用作一个单端输出的移动设备简单地被忽略的反相输出。the ideal operational amplifier理想运算放大器 in order to introduce operational amplifier circuitry, we will use an ideal model of the operational amplifier to simplify the mathematics [?m?θi?m?tiks] involved in deriving gain expressions, etc., for the circuits presented.with this understanding as a basis, it will be convenient to describe the properties of the real devices themselves in later sections, and finally to investigate circuits utilizing practical operational amplifiers.为了介绍运算放大器电路中，我们将使用一个理想的模型简化中获得的电路增益表达式等，所涉及的数学运算放大器的。有了这样的认识，以此为基础，可以方便的真实设备本身在后面的章节中描述的属性，最后调查利用实际的运算放大器电路。to begin the presentation of operational amplifier circuitry [?s?:kitri], then, it is necessary first of all to define the properties of a mythical “perfect” operational amplifier.the model of an ideal operational amplifier is shown in figure 9.首先介绍运算放大器电路，那么，它是必要的，首先要定义一个神话般的“完美”的运算放大器的性能。理想的运算放大器的模型是在图9中所示。defining the ideal operational amplifier ?= gain: the primary function of an amplifier is to amplify, so the more gain the better.it can always be reduced with external circuitry, so we assume gain to be infinite [?infinit]无限.增益：放大器的主要功能是放大的，所以更多的获得更好。它总是可以减少与外部电路，所以我们假设增益是无限 ?= input impedance: input impedance is assumed to be infinite.this is so the driving source won’t be affected by power being drawn by the ideal operational amplifier.输入阻抗：输入阻抗被认为是无限的。这是这样的驱动源将不会受到影响被绘制了理想的运算放大器的功率。?= output impedance: the output impedance of the ideal operational amplifier is assumed to be zero.it then can supply as much current as necessary to the load being driven.输出阻抗：理想的运算放大器的输出阻抗被假定为零。然后，它可以提供尽可能多的电流所必需的被驱动的负载。?= response time: the output must occur at the same time as the inverting input so the response time is assumed to be zero.phase shift will be 180?.frequency response will be flat and bandwidth infinite because ac will be simply a rapidly varying dc level to the ideal amplifier.响应时间：输出必须在相同的时间发生的反相输入端，这样的响应时间被假定为零。相移为180?。频率响应是平的，无限的，因为交流会只是一个快速变化的dc电平的理想放大器的带宽。
?= offset: the amplifier output will be zero when a zero signal appears between the inverting and non-inverting inputs.偏移量：当一个零信号之间出现的反相和非反相输入端，放大器的输出将为零。circuits and analyses using the ideal operational amplifier用理想运算放大器的电路及分析
the desirability of feedback是可取的反馈 consider the open loop amplifier used in the circuit of figure 10.note that no current flows from the source into the inverting inputhence, there is no voltage drop across rs and es appears across the amplifier input.when es is zero, the output is zero.if es takes on any non-zero value, the output voltage increases to saturation [?s?t???re???n] 饱和, and the amplifier acts as a switch.考虑图10的电路中使用的开环放大器。请注意，从源代码编译成的反相输入端因此没有电流流过，有没有rs两端的电压降和es出现整个放大器的输入。当es是零，其输出为零。如果es承担任何非零的值，输出电压增大到饱和，该放大器作为一个开关。the open loop amplifier is not practical一旦一个运算放大器推到饱和，它的行为是不可预测的。未指定恢复时间从饱和运算放大器的（除了电压限制类型）。它可能无法收回;输出锁存。作为输出级试图把车开到一个或其他铁路的一些运算放大器，尤其是轨到轨车型，可能会吸引大量的电流输出结构。对于运算放大器开环运行的详细信息，请参阅参考文献1。two important feedback circuits篇四：专业英语演讲稿范文
专业英语演讲稿范文
feet, the carriers of life good morning, ladies and gentlemen.i would like to tell you about an unusual assignment.i was surprised and amused when our teacher told us our homework was to wash our feet carefully.as i slowly soaped and rinsed my feet, i was beginning to understand why my teacher launched such a mission.she wanted us to realize that the feet were more helpful than we had ever imagined.surely, the hands are important.however it’s the feet that carry your whole body weight, and everything about your life.the feet carry you, as well as your hopes and dreams, and walk steadily upon the most solid ground, moving forward step by step, upon mountains and down valleys, over the smooth as well as the rough, through the bitterness as well as the joy.as i was washing my feet, i let my mind wander.i felt as if i was on a vast desert.looking around, i saw millions of footprints, large and small, deep and shallow, being the marks of existence, and the traces of life.and there i was, using my own feet, making my own path, towards the oasis of life„„ thank you.脚，生命的载体
女士们，先生们，上午好!我想告诉大家一份不寻常的家庭作业，老师布置我们当晚回家认真给自己洗一遍脚，听到后，我感到惊奇而有趣。
是啊，脚，我每晚必洗，但从未重视过。洗脚时，我津津有味地看着书，任双脚摩挲，互帮互助。但今晚，当我的双手触摸到自己的双脚时，是多么的舒服、惬意啊!心中，总是觉得手比脚高贵，人们用香皂洗手，并抹上护手霜，百般呵护;而脚踩在地上，即使有鞋袜，也总被认为是与灰土打交道的粗笨一族，并有不可避免的异味，脚，似乎成了身体中被忽视的部分。
我仔细地洗着脚，渐渐地，我明白了老师的用意：她布置这个特殊的任务，是为了让我们认识到脚，其实比我们想象的更伟大。
无可争议，手固然重要。可脚却承担着你生命的全部重量。
脚，负着你，你沉甸甸的希望和梦想，踩着踏实的大地，一步一步地前进，走上了高山也走下了峡谷，走过了平坦也走过了崎岖，走过了苦难也走过了幸福。
我在洗脚，手脚依偎，恍惚间，我仿佛置身于广袤的大漠中。环视四周，一串串大大小小深深浅浅的脚印，这是存在的证明，生命的印迹。
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