当前位置：文档之家 › Lecture2_dos

Lecture2_dos

  • 格式：pps
  • 大小：3.08 MB
  • 文档页数：34

Nanoscale EngineeringNanostructured materials: processing and propertiesHelen REVERONLECTURE 22LECTURE 2•The conclusions LECTURE 1•Extra-topics attracting your attention•Type of materials•Processing nanostructured 3D materials•The « nanoscale » is very SMALL, invisible…•A nanometer (nm) equals (IS) one billionth of a meter (10-9m)•All around you is nano… from materials to energy, the environment to medicine, electronics to agriculture…•Nano should make anything more efficient, more resistant,cheaper and less polluting•The scope of this course : 3D nanostructured materials!-Filling the 3 dimensions-Nanograins/ Micrograins + Nanoparticles-Interfaces control properties-Grain boundaries : dislocationsNanostructured materials :The former usually refer to condensed bulk materials that are made of grains withgrain sizes in the nanometer size rangeLECTURE 1 :Grain growth-2D Ostwald repining-Model grain growth withouth second phase-Model for grain growth with second phaseGrain growth refers to the increase in size of grains (crystallites )in a material at high temperature The boundary between one grain and its neighbour is a defect in the crystal structure and so it is associated with a certain amount of energy. As a result there is a thermodynamic driving force for the total area of boundary to be reduced. If the grain size increases, thenthe total area of boundary will be reduced.56 LECTURE 1 Question1: CdSe dots (Christian)Quantum dot of CdSe synthesis? And structure?Preparation of Cadmium Selenide Quantum Dot NanoparticlesFilmStructure:Many fundamental questions regarding their structural and opto-electronic properties remain unanswered. In particular, although transmission electron microscopy (TEM) indicates that CdSe nanoparticles adopt the wurtzite structure, resolving their surface geometry and assessing the influence of organic ligands on surface reconstructions is difficult. In contrast to Type IV and III-V semiconductors the size dependence of the optical gap of CdSe nanoparticles is largely independent of the surface termination. The origin of this insensitivity is not well understood. In addition, recent optical measurements indicate the presence of a sub-band gap state, with an unknown nature and dependence on the nanoparticle structure.CdSe Structureab-initio electronic structure calculations of CdSe nanoparticles with diameters up to 1.5~nm. Calculated relaxed atomic geometries with the corresponding ideal wurtzite structures . A substantial structural relaxation is observed on the surface of each cluster, although the wurtzite core is maintained. CdSe nanoparticles with ideal wurtzite structures are quasi-metallic and surface relaxations, not passivation by organic ligands, are responsible for opening up the gap in the clusters./Research/qsg-090205/cadmiumWires_dots.html Cd atomic radius is 0.16 nm Se atomic radius is 0.11 nm7The generic constituents of a thermal barrier system for a superalloy component are illustrated in Fig. 1, along with a summary of requisite attributes for performance and durability. The baseline thermal barrier or “top coat” is a 125–250 μm layer of porous ZrO2 partially stabilized with 7±1 wt.% Y2O3 (7YSZ), applied by either air-plasma spray (APS) or electron-beam physical vapor deposition (EB-PVD). Environmental protection relies primarily on a thin (<10 μm), dense Al2O3 layer (TGO), grown during service by thermal oxidation of the underlying metalNickel superalloy,nickel aluminideCurrent Opinion in Solid State andMaterials ScienceVolume 8, Issue 1, January 2004, Pages77-91Science 12 April 2002:Vol. 296. no. 5566, pp. 280 –284Thermal Barrier Coatings for Gas-TurbineEngine ApplicationsNitin P. Padture,1* Maurice Gell,1 Eric H.Jordan2Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines.Science 12 April 2002:Vol. 296. no. 5566, pp. 280 -284Thermal Barrier Coatings for Gas-Turbine Engine Applications Nitin P. Padture,1* Maurice Gell,1 Eric H. Jordan211 Master Schedule and OutlineWeek/Date Section TopicWeek 1/Sept. 12Intro T104Why is nano-scale specialDefinition of nanostructured materialsHow are nanostructured materials different?Week 2/Sept. 19Processing T104Types of materials. Processing of nanostructured polymers.Week 3/Sept. 26Processing T110Processing of nanostructured metals and ceramicsNanopowders: dispersion and rheologyAtomisationWeek 4/ Oct. 03Processing T110Nanopowders: characteristics, dispersion and rheologyWeek 5/Oct. 10Processing T110Nanopowders : dispersionWeek 6/Oct. 17Sintering T110Wet and dry forming methods. AtomisationPrinciples of sinteringOct. 24-Nov. 1Holydays + public holydayWeek 7/Nov. 7Sintering T110Solid state sintering: fundamentals.Week 8/Nov. 14Sintering T110Liquid phase sintering and two-step methodsWeek 9/Nov. 21Sintering T110Hot pressing, microwave sintering, spark plasma sinteringWeek 10/Nov. 28Properties T115Applications: nanocomposites, nano-bioceramics…Week11/Dec. 5Properties T104Student final presentationsWeek 12/Dec. 12Properties T104Student final presentationsDec. 19 and 26Christmas holydays•Polymers: covalent bond involving electron sharing between adjacent atoms (insulators)•Metals: metallic bond involving a « mobile gas of electrons »free electrons for electrical conduction •Ceramics: non metallic/polymeric and inorganiccovalent/ionic bond•Composites: combinations of individuals materialsex: fiberglass: composite of glass fibers embeddedin a polymer matrix (high strength of the fiber +the flexibility of the polymer matrix).+ amorphous(glasses)The mechanical and physical properties of materials are a direct consequenceof their interatomic forces (bonding)Breaking down of the bulk material into nano sizedstructures or particlesBottom-up approach Building up of a material from the bottom: atom-by-atom, molecule-by-molecule, orcluster-by-clusterTop-down approachBreaking down of the bulk material into nano sized structures or particlesNanoparticles + Forming+ SinteringFormingSintering(T,P)Metals,ceramicsBrittleFracturewhensubjected tostressThe most common procedure for 3D nanostructured materials processing:Nanoparticles OrganizingNanoparticlesHigh density/compactness(ideally 74%)(Forming)Creatingsolid-solidinterfaces High density (100%) (grains<100 nm)18 Processing of nanostructured PolymersDEFINITION•Polymers are defined as very large macromolecules consisting of repeating units of monomers•The monomers can be linked together to generate alinear polymer•Three types of polymers:-Linear-Branched-Cross linkedEx: polystyrene (molecular weight range: 1700-2 890 000)Polymerization of a simple polymer such as PE (Polyethylene) uses a single monomer (ethylene) and joins these together to form Polyethylene:The polymer therefore consists of repeated units of:Polyethylene is an example of a ‘homopolymer’ where all the mers are the same. If the repeat unit in the PE structure is called ‘A’ then the structure of a homopolymer is:In some cases two different types of mers (‘A’ and ‘B’) are joined together to form a copolymer:HMWPE: Molecular weight (Mw) of 143 000 g /molPolymers can be also produced from solutionsserv.chula.ac.th/~sanongn1/processing.pdfExtrusion MethodPolymer extrusion is a high volume manufacturing process in which raw material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames and wire insulation.-Raw thermoplastic polymers: polyethylene, polypropylene, acetal, acrylic, nylon(polyamides), polystyrene -Rotating screw –heated barrel (200-275°C): beds melt and are pushed trhough the barrel -Molten polymer enters the Die: gives the final product profile from a cylindrical profile to the final shape -Cooling/Cutting stepsExtrusion MethodExtrusion MethodThin film (flat or tubular) is the most common product. Other extruded products include pipe and tubing, monofilaments and textile fibers, flat sheet (anything over 0.25 mm), wire and cable covering, and a great variety of profiles such as window frames, gaskets and channels, and house siding. The products can be cut to length or rolled up as neededInjection moldingInjection moldingLarge variety of products with different shapes and sizes. Products with complex geometry that many other processes cannot create.-Extruder, home-made -PVC pipe extrusion line -Injection moldingPolymer/clay particles NanocompositesPolymer/clay particles NanocompositesIn this new class of material, nanosized inorganic filler(at least one dimension) are dispersed in polymer matrix offering tremendous properties improvementTypically smectite-type clays are used as fillers. Montmorillonite and hectorite layered structure are dispersed in polymer matrix.According with the bonding scenariuos between polymer chain and silicate layer, new material shows excellent mechanical properties compared to polymer: superior mechanical characteristics (higher tensile strength: 40% increase), heat resistance and chemical resistance.These results are achieved with only 0.1-10 %vol. addition clay nanosized.By embedding nanoclay structure in polymer matrix we obtain a new class of materials. Unlike to other nanotechnologies, this material found applications inmediately and is commercially developed./cable/safety/index.html/weimages/Publications/PU_nanocomposites_FR.pdfAt same temperatures>350°C the mass losses are significantly lower for the nanocomposite Indicating an improved stabilization (thermal stability)The heat release rate and the peak heat release are related to the « driven force » of the fire: Reduction for the peak of heat release was 44% for a TPU nanocomposite!Increase of the fire performance index: the time available to scape in a full-scale fire(flame retardancy improved in NC)Organic/clay particles NanocompositesFilm casting process onto a glass plate: 2D material! Casting process into a porous mold! 3D material!34 Next…Processing of nanostructured Metals…。

合集下载

lecture用法最全详解(含习题)

lecture用法最全详解(含习题)

2.lecturelecture /ˈlektʃə(r)/ 词频4n. 讲座；讲课；教训. vi. (开)讲座；讲课. vt. 训斥派：lecturer 词频2 n.演讲者；（大学）讲师①高义频vi.&n.（尤指大学中的）讲座；讲课；演讲go to/attend a lecture 听讲座deliver/give a lecture做讲座a lecture on/about 关于……的讲课/训斥e.g. He lectures on literature at Manchester University. 他在曼彻斯特大学教文学。

②低义频vi.&n.教训；训斥lecture sb. about/on...因……训斥某人give sb. a lecture 给某人一个教训e.g. He’s always lecturing me about the way I dress. 他总是对我的穿着说三道四。

e.g. I know I should stop drinking-don’t give me a lecture about it.我知道我该戒酒，别教训我了。

1.单词拼写（1）I went to the ___(讲座) he gave in the hall.(lecture)（2）He learned a ___(教训)from this thing-he should stop smoking for his health.(lecture)（3）Professor Smith will give a l___ in Fudan University this evening about the history of English.(lecture)（4）She suffered a bad cold. As a result, she missed the ___(讲座) she liked very much.(lecture)（5）She preferred that we should have the discussion right after the ___(讲座).(lecture)（6）Please stop___(lecture) me! I know I should quit smoking.2.语法填空（1）The ___ (lecture) spoke very clearly so that we could hear every word.(lecturer) 3. 完成句子（1）He ___ ___ ___ ___time management to first-year students___ ___ ___ ___.他在报告厅给一年级学生做关于时间管理的讲座。

lecture 02-2-handshake

lecture 02-2-handshake

What’s in a Handshake?Everything. It’s your first physical contact with someone, flesh to flesh. Your handshake is important from the point of view of:✧How you do it✧When you do it✧How it feels to someone elseA DESIRABLE HANDSHAKE FEELS:Firm, strong, representative of a person who makes decisions, take risks, and above all, takes charge.Warm and enthusiastic as if you are really glad to meet that personDry, pleasant to the touchAN UNDESIRABLE HANDSHAKE FEELS:Hesitant, apologetic, almost as if you were saying, ―I don’t really want to shake your hand, nor am I a decision maker.‖Weak, slippery, lifeless, like a handful of dead fish. Just as negative is the bone crusher handshake, which makes the other person feel in need of having his hand X-rayed.Wet and clammy, or cold, as though you have been holding an iced drink all day.When Do Y ou Shake Hands?All the time. For instance:✧When you run into someone you know✧When you say goodbye to the same person✧When someone comes in from the outside to see you in your office, and when he leaves✧When someone enters your home, or when you enter someone else’s home✧When you meet someone you know in a restaurant✧When you’re introduced to people in any business or social situation, and when you take leave of them✧When you are congratulating someone – after a speech, after an award presentationWhen Do Y ou Not Shake Hands?✧When the other person has his or her hands full✧When the person you want to greet is someone much higher ranked than you and to whom you really have nothingto say. In this case, it would look pushy for you to rush up to shake his hand and introduce yourself.1Points of protocol in HandshakingIf you enter a group, shake hands first with your host, and then with the other most senior people in the room. If everyone is clustered together – people of all ranks –don’t worry about whose hand you shake next, as long as you have shaken the hand of the host of this particular gathering.Protocol decrees that you shake hands with your host when you leave. Sometimes this is not possible, as when the host of your gathering is surrounded by people and it would be rude for you to interrupt. Use your common sense. If you can easily get to the host to thank him for the meeting, social event, or whatever, fine, shake his hand in goodbye. If you can’t easily get to him, leave and telephone your thanks or write him a note the next day.If someone doesn’t see your hand extended and doesn’t offer his or her hand to you, just draw back your hand and smile. That pers on is not rejecting you on purpose; he or she simply doesn’t see your extended hand. It’s embarrassing, two or three seconds for you, but it happens to every person who shakes hands often.When Y ou Have Clammy Hands✧If you have a tendency to have cold hands, stick your right hand in your jacket pocket to warm it up as youapproach a situation in which you’ll be shaking hands.✧Don’t hold iced drinks in your right hand. Hold them in your left, so that your shaking hand is nice and dry.✧If you have perennially clammy hands, before you shake someone else’s hand, give a quick swipe of your righthand on your skirt or trousers, so that when you present it, it’s dry. You can do it so quickly and gracefully, no one will be aware that you made the gesture.Being at Ease in Moving AroundYour good or bad manners are always with you, and when you move from one place to another, they become even more conspicuous. Whether you are moving through a living room, a darkened movie theater, the corporate auditorium, or the nar row aisle of a plane on its way to Xi’an, the way you move tells a great deal about you.Some people always move suddenly, jerkily, noisily. The right way to move is quietly and effortlessly, so no one is even aware of your movements.People who speak and laugh loudly as they move through an area upset the train of thought of others around them who may be trying to concentrate. (The noisy movers generally are people of low self-esteem, who are seeking to be noticed.)Young managers need to be told the following:✧Keep your eyes open when you move among people in public. Look around you; be aware of others.✧When you enter a room or have people entering your office, give the best seat to your client or customer—orsenior manager.2✧When you must move quickly amo ng people, perhaps carrying something that may hit them, look where you’regoing, apologize left and right with sincerity, and smile at the people. In most cases, their anger levels will be lowered by your apologetic behavior.Going Through DoorsIn the old days, ladies always preceded gentlemen going through doors, and in addition, a door was always rather ceremoniously held open for her. Today what you have to think about is not getting hit in the face by a door swung shut by the person ahead of you. In spite of the fact that no one will ever thank you or even notice your kindness. Be a door holder for others. It doesn’t matter if you are male or female, holding a door for the person coming behind is a common courtesy. It doesn’t matter if it’s the CEO or the bicycle messenger, just do it. It brings so much pleasure to people, and it makes people remember and like you.●Going Through Swinging Doors✧Regardless of your gender, let your guests — and anyone on staff who ranks considerably higher than you —prec ede you through the swinging door. Don’t make a big thing of it.✧When a group of five or more comes to your office, precede them, so you can show your guests where to go.✧If you know that a door is very heavy and difficult, precede any guest you may have w ith you by saying, ―This is aheavy door; I’ll go first and give it a shove.‖✧During the normal daytime movement of people, in office buildings or other kinds of buildings, whoever arrivesfirst at the door should enter and go through it. It’s as simple as that.Keeping Your Sense of Humor about Your GaffesGaffe: a mistake made from ignorance & stupidityUnless you have practiced recovering your composure after making some serious gaffes, you will probably continue to suffer far too much. Young executives, when they discover something they’ve done wrong, are generally over-mortified. And the more mortified they are, the more uncomfortable every one else is around them.Step back from a gaffe, ask yourself some questions and seek some answers:How serious was it?Your embarrassment may be more than that of the other people around you. Don’t blow the episode out of proportion, because as soon as you recover your own dignity, the others will recover theirs.Did anyone get hurt and did your company lose face or suffer harm because of your actions? If so, take instant remedial action, which could be anything from making a simple apology to mounting a compensatory campaign. Was there any humor to highlight in your gaffe situation?If there wasn’t any, can you injec t some, even at a later date, perhaps inserted3into your letter of explanation or apology?A serious gaffe requires apologies—verbal and written. But for the occasional misstep, laugh about your own mistake, because everyone around you is miserable for you.For example, when you are seriously late for an appointment with a client or customer: ―You know, Dave, we have a competition going on back at the office where we list the most irritating and infuriating kinds of behavior in the business world. I think m y keeping you waiting has probably won.‖If you make a joke about yourself, the others present will quickly feel at ease themselves, and everyone can get on with their lives. Humor, of course, should always follow, not lead, the obligatory apology. Your timing must be right, or your joke could fall terribly flat. Humor can never replace an apology; it merely augments the effectiveness of it and lightens it at the same time. And the humor is always more effective when turned toward yourself, rather than someone else.It’s human to err. Remind the person that to forgive is divine. If it’s your boss whom your gaffe has put on the spot, and if he or she doesn’t fire you but instead tells you to ―forget it,‖ you are blessed and perhaps home free, not to mention fortunate to be working for such a secure person.4。

DOS 基本命令介绍ppt课件

DOS 基本命令介绍ppt课件

注意：本教材之智慧財產權屬於仁寶電腦工業股份有限公司所有，僅限公司內部使用，否則將負民事賠償責任。
DOS的外部命令
EDIT〔Edit）--编辑命令 (Compal use “E3”) 其实它就是一个文本编辑软件， 使用它可以在DOS下方便地对文 本文件进行编辑，格式为“EDIT [文件名] [参数]”，它的参数 不是特别实用，我在此就不多分。 2.DOS的核心启动程序有Boot系统引导程序、IO.SYS、
MSDOS.SYS和。它们是构成DOS系统最基础的几 个部分，有了它们系统就可以启动。 3.但光有启动程序还不行，DOS作为一个字符型的操作系统， 一般的操作都是通过命令来完成。DOS命令分为内部命令和 外部命令。内部命令是一些常用而所占空间不大的命令程 序，如dir、cd等,它们存在于文件中，会在系 统启动时加载到内存中，以方便调用。而其它的一些外部 命令则以单独的可执行文件存在，在使用时才被调入内存.
DOS的內部命令
DEL--删除文件 格式为“DEL [盘符][途径][文件名][参数]” 比如:DEL C:\a.bat ”。 它有一个参数：“/P”，可以使用户在删除多个文件时对每个文件都显 示删除询问
/P
注意：本教材之智慧財產權屬於仁寶電腦工業股份有限公司所有，僅限公司內部使用，否則將負民事賠償責任。
2.如“*.BAT”就代表当前目录下所有后缀名为“BAT”的文件。 在同一个目录下，不允许存在相同名称的文件或目录。
注意：本教材之智慧財產權屬於仁寶電腦工業股份有限公司所有，僅限公司內部使用，否則將負民事賠償責任。
DOS的內部命令
CD--进入指定目录 格式为“ CD＋空格＋子目录名〞,例如“CD DOS”。 注意：只能进入当前盘符中的目录。其中“CD\”为回到根目录， “CD..”为回到上一层目录。
《DOS操作系统》课件

《DOS操作系统》课件


兼容性：与现代操作系统的 兼容性，如Windows、 Linux等
创新性：引入新的技术和功 能，如云计算、人工智能等，
提高系统的竞争力
THANK YOU
汇报人：
文件名和扩展名：8.3格式，如 FILENAME.TXT
文件属性：只读、隐藏、系统、存档、 正常
文件操作：创建、删除、复制、移动、 重命名
磁盘管理：格式化、分区、合并、删 除分区
DOS的命令行界面
界面组成：命令行窗口、命令提示符、命令输入框、命令输出框 功能：执行命令、查看系统信息、管理文件和目录 命令格式：命令名+参数+选项 常用命令：dir、cd、copy、del、format等
文件操作命令
●
dir：列出当前目录下的文件和子目录
●
cd：改变当前目录
●
mkdir：创建新目录
●
rmdir：删除空目录
●
copy：复制文件
●
move：移动文件
●
del：删除文件
●
type：显示文件内容
●
ren：重命名文件或目录
●
attrib：设置文件或目录属性
●
chkdsk：检查磁盘错误
●
format：格式化磁盘
安全性：DOS安全性较低，容易受到病 毒攻击，Windows安全性较高，有完 善的安全机制
兼容性：DOS兼容性较差，只能运行 DOS程序，Windows兼容性较好，可 以运行多种操作系统的程序。
DOS操作系统的适用范围和用户群体
适用范围：主 要用于早期个 人电脑和早期
服务器
用户群体：早 期电脑爱好者、 程序员、系统
DOS的内存管理
内存分配：DOS操作系统将内存分 为多个段，每个段都有特定的用途