1、Objectives and OutcomesLearn how to describe in technical writing:Spatial or structural description Functional or process description Chronological or operational description Graphics Used in DescriptionI.IntroductionTo describe is to create a mental picture in words.A technical description gives an
2、 account of:an object(e.g.an atom or a heart),a mechanism(e.g.an engine),a place(e.g.a construction site),a process(e.g.the operation of a computer).These descriptions often follow a two-part structure:(1)An introduction that includes either an overview of the description or a statement of the focus
3、 of the description.(2)A part-by-part description of what is being described.II.Introductory Section of TDThe introduction of technical description gives an overview of the description,which may include some or all of the following information:Definition of the object to be described Overview of the
4、 description including functions,uses,special features,etc.对描述的概述，包括 功能、用法、特性等等。Purpose(of a mechanism)Location(of a place)The physical characteristics(of an object)including size,shape,weight,color,material,etc.Example of an Introduction of Technical Description 1A microscope is an instrument used
5、for viewing small objects,especially objects that are too small to be seen by the unaided eye.2It is an important tool of science because it is widely used in examining small specimens such as bacteria,cells and crystals in metals,etc.3Microscopes can be generally classified into three categories:op
6、tical or light microscopes光学显微镜,electron microscopes电子显微镜,and scanning probe microscopes 扫描显微.4This article mainly discusses the optical microscope.This introduction gives an overview of the description,which includes the following information:S1:The definition of a microscope and its purpose S2:The
7、 usages of the microscope S3:The classification of microscopes according to their features S4:The range of description 描述范围 in this articleIII.Section of Part-by-Part DescriptionThe major section of a description is a part-by-part description of the object.There are generally three ways to organize
8、the part-by-part description:Spatial organizationFunctional organization Chronological organization1.Functional Organization 按功能组织按功能组织信息信息A functional organization is used to describe how something works.If you organize a description functionally,you would describe a mechanism according to how it w
9、orks 按照工作原理描述一个机械装置.The optical microscope(often referred to as the light microscope)is the oldest and simplest of the microscopes.The simplest optical microscope is a magnifying glass,a convex lens that bends or refracts the light rays from the object to produce an enlarged image.一个凸球面镜，它可以折射来自物体的光
10、线以产生一个放大图像.A compound microscope consists mainly of two lenses:an objective lens 物镜 and an eyepiece 目镜(also called the ocular lens).The objective lens is a high-powered magnifying glassa lens with a very short focal length.物镜式高倍放大镜，个焦距很短的透镜.It can be brought very close to the specimen being examined
11、 so that the light from the specimen comes to a focus inside the microscope tube.可以把它移动到离检验标本很近的位置，从而使来自于标本的光线在显微镜筒中聚焦。This creates an enlarged image of the subject.The ocular lens then magnifies this image,producing an even larger image.这样会产生一个放大的标本影像。目镜对这一影像进行放大，从而产生一个更大的影像。Example:Functional Orga
12、nization DescriptionFeatures of the previous example:In the description of the microscope,the author follows a general-to-specific order 从特殊到一般的顺序.The author describes the general working principle of the simplest optical microscope firstand then a compound microscope in more details.2.Spatial Organ
13、ization 按照空间位置组按照空间位置组织信息织信息A spatial organization(or static description静态描述)describes the appearance,layout,structure or organization of something.It includes two major steps:(1)Analyze the object by partitionseparate the object into its parts.(2)Describe the structure of the object from one part t
14、o the next in a logical order:from left to right(or right to left);from top to bottom(or bottom to top);from inside to outside(or outside to inside).Optical microscopes generally consist of three parts:the tube,the arm and the foot,镜筒、镜臂和镜座.as is shown in Figure 11-6.The foot is the base on which th
15、e arm stands.The arm is the upright support that holds the tube.The tube contains the lenses for magnification.镜座是支持镜臂的基础。镜臂式镜筒的垂直支柱。镜筒中装有进行放大的透镜。The arm is hinged to the U-shaped foot so that it can be tilted to allow the viewing angle to be adjusted.The arm consists of a stage,a mirror and two adj
16、ustment knobs.The stage is a platform on which the specimen is placed.The mirror,fixed under the stage,reflects light through an opening in the stage to illuminate the specimen.On the upper part of the arm is a course-adjustment knob,which is used to focus the microscope by moving the tube within th
17、e arm.On the lower part of the arm is a fine-adjustment knob,which moves the tube a small distance for final focusing of a high-power lens.镜臂铰链在U型镜座上，以便镜臂能够倾斜以调整观察角度。镜臂由一个镜台、一个反光镜和两个调节钮组成。镜台式一个放置标本的平台。反光镜安装在镜台下面，通过镜台上的一个小孔（通光孔）用反射光照亮标本。镜臂的上部是粗调节旋钮，通过移动镜臂内的镜筒使显微镜聚焦。镜臂下部是细调节旋钮，对镜筒距离进行细微调节，以便对高倍镜进行最后聚焦
18、。The tube is mainly composed of two parts:the upper part and the lower part.The upper end of the tube holds the eyepiece(or ocular lens).The lower part of the tube holds the objective lens.In most cases,two or more objective lenses of different power are mounted on a revolving nosepiece that can be
19、rotated to bring the desired lens into place.镜筒主要包括两个部分：上部和下部。目镜安装在镜筒的顶端，物镜安装在镜筒的下部。在多数情况下，两个或多个不同倍数的物镜安装在一个换镜旋座上，通过旋转来调换所需要的物镜Example:Spatial Organization Description 按照空间位置进行组织描述按照空间位置进行组织描述This description follows the general-to-specific 从一般到特殊 and outside-to-inside 从外至内order.P1:Describes how man
20、y major parts a microscope has and how they are connected to one another.P2:Describing specifically the mechanical parts on the arm.P3:Describes the structure of the tube that is held by the arm.3.Chronological Organization 按照时间先后顺序组织信息A chronological organization is a description that follows the o
21、rder of time.It describes how to do something and thus is also called an instructional or operational description 使用或操作描述.It is widely used in the follow types of writing:User manuals:to explain steps a person should follow Research reports:to describe actions the researchers took Feasibility studie
22、s:to explain tests conducted Proposals:to describe work to be done A microscope is an expensive and delicate instrument that should be handled with care.To prepare a microscope for use,turn the nosepiece so that the objective lens with the lowest power is in the viewing position.Next,lower the tube
23、by turning the coarse-adjustment knob until the objective lens is just above the opening in the stage.Finally,look through the eyepiece and adjust the mirror so that a bright circle of light appears in the eyepiece.The microscope is now ready for use.准备使用显微镜时，首先旋转物镜转换器，使最低倍数的物镜处于观察位置。接着，通过转动粗调节钮使镜筒下
24、降，直到物镜正好位于镜台的通光孔上方。最后，通过目镜观看，并调节反光镜，使一个明亮的光环出现在目镜里。此时，显微镜已经准备好可以使用了。To prepare specimens for viewing,make sure that the specimens are transparent,or have been made transparent,so that light can shine through them.Place the specimen to be viewed on a glass slide that measures 76 mm long and 25 mm wid
25、e.在准备观察标本时，确认标本时透明的，或者把标本做成透明的，以便光线能够透过标本。把观察的标本放在一个76毫米长、25毫米宽的玻片上。To view a slide,place it on the stage with the specimen directly over the opening.Hold the slide in place with the clips on the stage.Look through the eyepiece and turn the coarse-adjustment knob to raise the lens up from the slide
26、until the specimen comes into focus.观察玻片标本时，把它放在镜台通光孔的正上方。用镜台上的弹簧夹夹住玻片标本。通过目镜观看，旋转粗调节钮使透镜从玻片处升起，直到使标本聚焦。To view more details of the specimen,turn the nosepiece to an objective lens with higher power,and then focus the objective lens with the fine-adjustment knob.You can also move the slide on the st
27、age to bring different parts of the specimen into view.要观察标本的更多细节，把物镜转换器转向一个更高倍数的镜头，然后通过调节细调旋钮使物镜聚焦。你也可以移动镜台上的玻片标本来观察标本的不同部分。Example:Chronological Organization Descriptionof a Microscope In this example,the description follows the time order(what to do first;what to do next.)exactly.P1:Provides warn
28、ings on how to handle the microscope before the operation.P2:States how to prepare the machine for work.P3:States how to prepare the specimen for viewing.P4:Describes how to view the specimen through the microscope.P5:Explains how to view details and different parts of the specimen.Here you can find
29、 that both the description of paragraphs and the description within each paragraph follow the chronological order.In actual technical description,these three methodsthe functional descriptionthe spatial descriptionthe chronological descriptioncan be used either separately or in combination.A complet
30、e description of a mechanism may include all the three methods to describe its structure(what it looks like),its function(how it works),and its operation(how to use it).IV.Graphics Used in Description Graphics can make description easier to understand by showing relationships more clearly than words
31、 alone.They help readers focus on key portions of the description,and provide detailed information efficiently.Commonly used graphics with technical description are as follows:Photographs Drawings Diagrams1.Photographs Showing the reader exactly what an object looks like.Providing an accurate sense
32、of proportion and relation between the parts.Showing only the outer surface features of the thing.Providing more details than is necessary,which might lead to confusion.Figure 1 A photocopier Figure 2 A motor in a videotape recorderGuidelines for Using Photographs:1)Trim the photograph to eliminate
33、needless details.Figure 3 A photo with too many details Figure 4 The cropped version Replacing the Microfilter Activation Unit.2)Take the photograph at the right angle of vision so that readers would be able to identify or view the item they are supposed to see.3)Provide a frame of reference by incl
34、uding a person,a hand,a tool,or other familiar objects in the photo.Figure 5 Showing an angle of vision Figure 6 Showing how the work is done Titration in measuring electron-spin resonance.Antibody screening procedure.4)Label all the parts readers need to identify.5)Number the photograph in its orde
35、r of appearance,and if necessary,include a prose caption.Figure 7:A photograph with labels to indicate functional partsStandard flight deck for a long range jet.2.Drawings 绘图绘图Drawings have three advantages over photographs:Direct the readers attention to specific parts of the object.Provide clearer
36、 and more useful details by removing unessential details.Present the object in a three-dimensional view 三维图像.Figure 1 A photographFigure 2 A drawing showing the lenses and light path in a microscopeThe drawing on the left shows the external parts of a microscope.An operator adjusts these parts to vi
37、ew a specimen.The cutaway drawing on the right shows the path that light follows when passing through the specimen and then through the lenses and tubes of the microscope.The drawings make it much simpler and easier for the reader to see the structure and understand the working principles of the ins
38、trument.3.Diagrams 结构图结构图Diagrams(flowcharts,blueprints,etc),can be used when you want to emphasize the relationship among objects rather than their appearance.It allows the writer to show the abstract relationship among the parts of the mechanism or the place.显示一个场所或机械装置各部分之间的抽象关系。It is neither rep
39、resentational nor proportional;you cant get a sense of distance,size,or shape of the object.Figure 1 A photo of refrigerator Figure 2 A diagram showing relation and functionV.Guidelines for Technical Description1.Clarify the audience and the purpose,which determine the contents and methods of descri
40、ption.2.Give an introduction at the beginning.Provide information the reader might need to understand the description.3.Choose the right methods of organization:functional,spatial or chronological.They can be used either separately or in combination.4.Use accurate terminology and definitions to make your description precise and clear.5.Use transitions,such as and,first,next,at last,etc.,to make the description coherent in meaning.6.Use proper graphics,such as photographs,drawings,and diagrams,to assist your verbal description.
