(商业)等额本息月供速算表2012.7.5(10%,20%,30%)
2012年高考英语试卷
2012年高考英语试卷2012年高考英语全国卷（人教版适用）第一部分：听力（共两节，满分30分）第一节（共5小题；每小题1.5分，满分7.5分）听下面5段对话。
每段对话后有一个小题，从题中所给的A、B、C三个选项中选出最佳选项，并标在试卷的相应位置。
听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题。
每段对话仅读一遍。
1. What will the woman do this afternoon?A. Do some exercise.B. Go shopping.C. Wash her clothes.2. Why does the woman call the man?A. To cancel a flight.B. To make an apology.C. To put off a meeting.3. How much more does David need for the car?A. 5,000.B. 20,000.C. $25,000.4. What is Jane doing?A. Planning a tour.B. Calling her father.C. Asking for leave.5. How does the man feel?A. Tired.B. Dizzy.C. Thirsty.第二节（共15小题；每小题1.5分，满分22.5分）听下面5段对话或独白。
每段对话或独白后有几个小题，从题中所给的A、B、C 三个选项中选出最佳选项，并标在试卷的相应位置。
听每段对话或独白前，你将有时间阅读各个小题，每小题5秒钟；听完后，各小题将给出5秒钟的作答时间。
每段对话或独白读两遍。
听第6段材料，回答第6、7题。
6. Where does the conversation probably take place?A. In a hotel.B. In a restaurant.C. In a supermarket.7. What does the man ask the woman to do?A. Sign her name.B. Confirm the order.C. Pay a deposit.听第7段材料，回答第8、9题。
KB教材介绍-2012.7.1PPT课件
主题式情景化教学
3
KB1 框架总结
层次分明， 利于划分课时
每 2 页为一个循环 每个单元当中： 1，3，5 页为新知识呈现 2，4，6 页为强化复习
4
互动式教学:互动 DVD
Time for the Interactive DVD !
互动性强, 课堂亮点（Suzy’s / Music Room）
提供各种活动、比赛参加机会，
充分调动孩子的学习积极性，培
养孩子们学习英语的兴趣。
19
Traits
家庭式人物设计
Star family
Review
Beliefs
Multi-intelligences
Theory
强调动手能力 多种智能的融合
双重故事教学法
Toy presentation
CLIL
Content learning
24
Teacher-Oriented
教学目标 目标语言
热身活动 演示
Teacher’s Book
PB 内容讲解
教师用书
YLE 标识 AB
内容讲解
补充活动 结束本课
25
精彩样张
Classroom language 课堂用语
Extra activities 补充活动
Teacher’s Book Photocopiable activities 可复印的活动
Speaking Cycle KB1 Unit Structure
Review Cycle
51
Vocabulary KB2 Unit Structure Cycle 52
Sentence
KB2 Unit Structure
化工原理课程设计---列管式换热器的设计
化工原理课程设计---列管式换热器的设计列管式换热器是一种常用的换热器类型，其结构简单、传热效率高、维修方便等优点使其在工业生产中得到广泛应用。
该换热器由多个平行排列的管子组成，热流体和冷流体分别流过管内外，通过管壁传递热量，实现热量交换。
根据不同的流体流动方式，列管式换热器又可分为纵向流式和横向流式两种形式。
其中，横向流式换热器传热效率更高，但结构较为复杂，维修难度较大，因此在实际应用中需要根据具体情况进行选择。
浮头式换热器的特点是管板和壳体之间没有固定连接，只有一个浮头，管束和浮头相连。
浮头可以在壳体内自由移动，以适应管子和壳体的热膨胀。
这种结构适用于温差较大或壳程压力较高的情况。
但是，由于管束和浮头的连接是松散的，因此需要注意防止泄漏。
U型管式换热器：U型管式换热器的管子呈U形，两端分别焊接在管板上，形成一个U型管束。
壳体内的流体从一端进入，从另一端流出，管内的流体也是如此。
这种结构适用于流体腐蚀性较强的情况，因为管子可以很容易地更换。
多管程换热器：多管程换热器是将管束分成多个组，每组管子单独连接到管板上，形成多个管程。
这种结构可以提高传热效率，但也会增加流体阻力。
因此，需要根据具体情况来选择多管程的数量。
总之，列管式换热器是一种广泛应用于化工及酒精生产的换热器。
不同的结构适用于不同的工艺条件，需要根据具体情况来选择合适的换热器。
在使用过程中，需要注意保养和维护，及时清洗和更换损坏的部件，以保证换热器的正常运行。
换热器的一块管板与外壳用法兰连接，另一块管板不与外壳连接，这种结构称为浮头式换热器。
浮头式换热器的优点是管束可以拉出以便清洗，管束的膨胀不受壳体约束，因此在两种介质温差大的情况下，不会因管束与壳体的热膨胀量不同而产生温差应力。
但其缺点是结构复杂，造价高。
填料式换热器的管束一端可以自由膨胀，结构比浮头式简单，造价也较低。
但壳程内介质有外漏的可能，因此不应处理易挥发、易燃、易爆和有毒的介质。
菲律宾降税清单2012-2018
EHP EHP EHP EHP EHP EHP NT1 NT1 EHP NT1 EHP NT1 EHP HSL HSL HSL HSL EHP EHP EHP NT1 NT1 EHP HSL HSL EHP NT1 NT1 EHP NT1 NT1 EHP NT1 NT1 NT1 NT1 NT1 NT1 EHP NT1 HSL HSL HSL HSL NT1 NT1 NT1 NT1 NT1 NT1 NT1 NT1 EHP
0101.21.00 0101.29.00 0101.30.10 0101.30.90 0101.90.00 0102.21.00 0102.29.10 0102.29.90 0102.31.00 0102.39.00 0102.90.10 0102.90.90 0103.10.00 0103.91.00A 0103.91.00B 0103.92.00A 0103.92.00B 0104.10.10 0104.10.90 0104.20.10 0104.20.90A 0104.20.90B 0105.11.10 0105.11.90A 0105.11.90B 0105.12.10 0105.12.90A 0105.12.90B 0105.13.10 0105.13.90A 0105.13.90B 0105.14.10 0105.14.90A 0105.14.90B 0105.15.10A 0105.15.10B 0105.15.90A 0105.15.90B 0105.94.10 0105.94.40 0105.94.91A 0105.94.91B 0105.94.99A 0105.94.99B 0105.99.10A 0105.99.10B 0105.99.20A 0105.99.20B 0105.99.30A 0105.99.30B 0105.99.40A 0105.99.40B 0106.11.00
2012英语高考试题及答案word版
2012英语高考试题及答案word版一、听力理解（共20分）1. What does the man mean?A. He has to leave now.B. He is too tired to go on.C. He will go to the party later.D. He is not interested in the party.答案：C2. What is the woman's opinion about the book?A. It's difficult to understand.B. It's more interesting than she expected.C. It's written in a simple style.D. It's not as good as she had thought.答案：B3. Why does the man make the phone call?A. To ask about the flight time.B. To book a flight to New York.C. To confirm his flight reservation.D. To cancel his flight reservation.答案：D...二、阅读理解（共40分）A篇4. What is the main idea of the passage?A. The importance of a good breakfast.B. The effects of missing breakfast.C. The benefits of regular exercise.D. The relationship between diet and health.答案：B5. According to the passage, which of the following is true?A. Skipping breakfast can lead to poor concentration.B. Having a big lunch can make you feel sleepy.C. Regular exercise can help you lose weight.D. Skipping breakfast is not harmful to health.答案：AB篇6. What is the author's purpose in writing the article?A. To introduce a new method of teaching.B. To criticize the traditional teaching methods.C. To encourage students to be more creative.D. To suggest that teachers should be more patient.答案：C7. What does the author think about the current education system?A. It is too focused on memorization.B. It is too strict and not flexible enough.C. It is too old-fashioned and needs to be updated.D. It is too lenient and does not demand enough from students.答案：A...三、完形填空（共20分）8. A. although B. because C. if D. unless答案：B9. A. surprised B. disappointed C. excited D. worried答案：C10. A. decided B. forgot C. remembered D. refused答案：A...四、语法填空（共20分）11. The students were all excited about the coming sports meeting, ________ they had been looking forward to for months. 答案：which12. ________ the weather was fine, they went out for a picnic. 答案：Since13. ________ he was very tired, he kept on working.答案：Although...五、短文改错（共20分）14. One day, Tom and I were walking in the street when we sawa man was lying on the ground. (两个错误)答案：去掉第二个was；lying改为lie15. I used to go to school by bike, but now I am used to go to school by underground. (两个错误)答案：去掉to；underground改为subway...六、书面表达（共40分）16. Write an essay of about 120 words on the topic "The Importance of Teamwork". You should write clearly and coherently, and support your view with appropriate details.范文：Teamwork is an essential aspect of success in today's world. It allows individuals to combine their strengths and compensate for each other's weaknesses. Through teamwork, people can achieve goals that would be impossible for a single person. Moreover, working in a team fosters communication and problem-solving skills, which are valuable in both personal and professional life. In conclusion, the importance of teamwork cannot be overstated, as it is the key to unlocking our full potential.答案：略请注意，以上内容仅为示例，实际的试题及答案应根据具体的考试内容进行编写。
A few useful things to know about machine learning
Things to
Know About
Machine
Learning
Machine learning systems automatically learn programs from data. This is often a very attractive alternative to manually constructing them, and in the last decade the use of machine learning has spread rapidly throughout computer science and beyond. Machine learning is used in Web search, spam filters, recommender systems, ad placement, credit scoring, fraud detection, stock trading, drug design, and many other applications. A recent report from the McKinsey Global Institute asserts that machine learning (a.k.a. data mining or predictive analytics) will be the driver of the next big wave of innovation.15 Several fine textbooks are available to interested practitioners and researchers (for example, Mitchell16 and Witten et al.24). However, much of the “folk knowledge” that
carbon based refractories
Fig.1.Base material pyramid with the location of the refractory materials.Table 1.Refractory Consumption by the Steel Industry Worldwide517Journal of the CeramicSociety of Japan 112[10]517 532(2004)Carbon Based RefractoriesJ [{ ÜL ÏΨÌT vEmad Mohamed M.EWAISRefractory &Ceramic Materials Lab.,Central Metallurgical R &D Institute (CMRDI ),P.O.BOX 87Helwan,11421Cairo,EgyptCarbon based or containing refractories has been attracting great attention because of their unique properties e.g.high thermal conductivity,low thermal expansion,high resistance to thermal shock and chemical inertness to the slag.They are classified into two groups;carbon /bricks /blocks and carbon containing materials.Carbon containing materials are further classified into carbon containing basic refractories and nonbasic refractories.Manufacturing processes are considered.The properties e.g.physical,thermal,mechanical and chemical are reviewed.Antioxidant and bonding materials for these types of the refractory products are reviewed.Their applications are also considered.[Received April 26,2004;Accepted July 30,2004]Keywords :Refractories,Carbon,Graphite,Magnesia,Dolomite,Alumina,Zirconia,Manufacturing,Antioxidants,Bonding,Physical,Thermal,Chemical,Mechanical,Application1.IntroductionRefractories are materials (usually nonmetallic )that maintain sufficient physical and chemical stability identity to be used for structural purposes in high temperature environments encountered in the process industries.While refractories are always exposed to high temperatures,the effect of other environmental conditions play a significant role in the performance of refractories during service.These include:mechanical stresses,thermal cycling and associated stresses,erosion and corrosion by hot gases and such molten materials as metals,slags,or glasses.Today,refractories are absolutely essential to industry.Without refractories,few manufacturing processes could be carried out.1)The production of metals,cement,glass,petroleum products,and much of our electrical energy depends on refractories.Yet,few people know relatively what refractories are or realize their importance,because these materials seldom come to the attention of the general public.Refractories are usually sent directly from their point of manufacture to another factory,where they are used to make consumer items that bear no trace of the refractories that were essential for their production.In addition to the category of refractories characterized by largescale used in the process industries,there are others that are used for more specific applications.For example,in the aerospace industry extremely high temperatures are encountered from propulsion systems and friction heating at high velocities in the atmosphere.There are also applications in the field of nuclear energy.Such applications that may require the massive use of refractories are a vital factor in the success of a particular system.Refractories are classified primarily on the basis of their chemical composition and the forms in which they are used.2) 8)To a lesser extent,refractories may be identified by association with a particular function such as thermal insulation,or a special manufacturing process such as fusion casting.Although the types of refractories manufactured for the industrial use are vast,it should be recognized that only few chemical elements form refractory compounds are available in sufficient quantities to be used economically.The preponderance of all g heavy h refractories are manufactured from compounds that involve the elements:silicon,aluminum,magnesium,calcium,chromium,and zirconium.The oxides of these elements are singly used or in various combinations.Recentlyand with increasing frequency,these elements are used in combination with carbon,Fig.1.9)Carbon or graphite refractories are also used with carbon as the sole constituent in the form of blocks or bricks.It is well known that the major refractories production is associated with the steel industry,i.e.if steel production increases,refractories production also increases,and vice versa.10),11)Recently,a dramatic reduction of refractory consumption per ton of steel has been achieved in the iron and steelmaking industries.This is attributed to improve operations specifically in process control and hot gunning repair.It also results from the development of continuous casting processes.The quality of refractories,specifically carbon containing or based refractories,truly advanced composite materials,also played an important role in achieving reduction in refractory consumptions (See Table 1).12),13)Fig.2.Crystal structure of graphite.518Carbon Based RefractoriesIn summary,there are many types of refractories.Carbon containing or based refractories are a class of refractories according to chemical composition classification.Because of the progress in this class and its application to iron and steelmaking processes,the refractories containing or based upon carbon (carbon bricks /blocks,carbon containing basic refractories,carbon containing nonbasic refractories )are reviewed in the light of these processes.2.Carbon and graphite refractoriesElemental carbon is found in nature in the form of diamonds,graphite and above all as coal.For refractory purposes natural and artificial graphite (coke from coking plants )are important for the manufacture of carbon bricks.The rawmaterials for carbon blocks should have ash content as lowas possible as w ell as a high yield.14)Because carbon or graphite refractories are both made up of the single element carbon,their distinction depends upon the basis of their crystal structure.Carbon refractories generally do not have a wellordered crystalline structure and may be considered amorphous,depending on the initial rawmaterials and the temperature that reached during the manufacturing.The graphite structure is well known,15) 17)Fig.2and indicates a planar structure with an infinite two dimensional array of carbon atoms arranged in hexagonal networks in the form of a giant aromatic molecule.The carboncarbon bond (covalent )in the plane is strong as indicated by the interatomic distance of 0.142nm where the bonding (van der Waal type )between the planes is weak the interatomic planar spacing being 0.304nm.Consequently,graphite has a layered structure and may occur in flakes or showpreferred orientation of its crystallites because of the alignment of the crystallites in fabrication process i.e.the planar structure results has anisotropic properties.The properties of graphite,in particular single crystal graphite,in terms of thermal expansion,thermal conductivity and compressibility are attributed to the structure.16),18)Thermal expansion perpendicular to the planes is 200times that parallel to the planes.Thermal conductivity paralleled to the planes is 200times that perpendicular to the planes.Its compressibility is 104 105times greater in the direction perpendicular to the plane.However,the degree of anisotropy decreases for the graphite components produced from a random array of graphite crystallites and the properties of such a body can't be readily inferred from orientation factors in the random structure.This is the case for manufactured carbon refractories as they contain amorphous carbon and /or well ordered crystalline structure.Interesting properties for this refractory class in terms ofdistribution of size pore,lowporosity,lowthermal expansion and zero permanent linear change at 1600 C,were reported,in particular,if this type is manufactured from anthracite calcined at very high temperatures (1600 1800 C ),extruded,impregnated.This improvement in the properties was based on the well distribution of the grain size and,in turn,minimizing the intergranular spacing of the product.19),20)Three groups of refractory bricks out of carbon have been reported:amorphous,partgraphite or semigraphite and graphite bricks.In recent years two further types designated as g microporous h were developed from the first two groups by additions of additives to improve their wear resistance.20)2.1ManufacturingCarbon and graphite refractories are naturally occurring graphite,coal,petroleum coke,coaltar pitch,artificial graphite,coke from mines,gascalcined anthracite and electrically calcined anthracite.21)Tarpitches,petroleum pitches and other organic materials are used as binders.The raw materials are prepared,ground,sieved,classified,mixed to batches depending on the desired property values,heated to approximately 160 C depending on the type of bond,andmixed w ith binder to get the socalled g green batch h org green mixture.h Next the mix is shaped.Vacuum vibration equipment,die presses,extrusion presses,isostatic presses and ramming equipment are used to form the batch /mixture intothe desired shape.After shaping the socalled g green h shape issubjected to a firing process up to approx.1200 C.The binder converts to coke.It is possible to accomplish subsequent densification and compaction by impregnating the blocks with impregnation agents,which are similar to the binders with regard to their composition.The impregnation agent,which has entered the pores,is also converted to coke during further firing'.20) 22)2.2Physicochemical propertiesCarbon and graphite are not wet by most molten materials because of the lowinterfacial tension betw een carbon or graphite and molten materials.They have excellent thermal shock resistance,and their strength increase when they are heated.At 2500 C,the tensile strength of graphite is roughly twice as great as its room temperature tensile strength,which is approximately 2000psi.1)Carbon and graphite have a range from good to superb electric conductivity,thermal conductivity and lowexpansion coefficients.Their thermal shock resistance are sufficient for standard applications.Despite good thermal conductivity and thermal shock resistance the application of carbon blocks is restricted because they are susceptible to be attacked by oxygen,steam and CO 2in an oxidizing atmosphere above 400 C.The wear mechanisms for carbon bricks lining the hearth and hearth wall of blast furnace were reported.23)Six wear mechanisms are responsible for the damage of carbon bricks;1)the dissolution of carbon in pig iron.24)2)the pickup of potassium oxide and migration of it into the brick to temperature zones of 900 C and reaction with the crystalline phases of carbon e.g.mullite,a crystoballite and a quartz under theformation of kalsilite (K 2O E Al 2O 3E 2SiO 2)and leucite (K 2O E Al 2O 3E 4SiO 2).25)These reactions are combined with a volume increase,which causes a destruction of the brick texture.Further pickup of potassium and the formation of potassiumcarbon compounds of the formula C 8K,C 24K and C 60K causes a swelling of the carbon bricks and a complete disintegration of it.3)MnO pickup of the brick and its reaction with ash compounds at temperature above 1200 C forming manganese aluminium silicates.This in turn reduces the modulus of rupture of the brick.4)the reaction of pickedup ZnO with519 Emad Mohamed M.EWAIS Journal of the Ceramic Society of Japan112[10]2004binding phases of the carbon bricks destroying it,formation of zinc orthosilicate(2ZnO E SiO2)or zinc aluminate during shut down of the blast furnace.25)5)oxidation of carbon by water vapor26),27)6)thermal stress due to the existing pressure within the lining.24)2.3ApplicationsBecause their properties,graphite and carbon refractories are serious contenders for applications in a reducing environment.Blast furnaces use appreciable quantities of carbon and graphite,particularly in the hearth,but carbon and graphite may also find application in the bosh and other places such as tapholes.28)With watercooled shells,cupolas have been lined with carbon in the wells.Because of its high electrical conductivity, graphite is used for electrodes in electric furnaces to generates the arc.Because graphite can be easily machined,complicated shapes can be cut from stockin the form o bars,slabs,or cylinders.In order to accomplish the reduction process at electric arc temperature for the production of Si,FeSi, FeMn...etc.,carbon electrodes with various graphite additives are applied.In these furnaces the bottoms are partially lined with carbon blocks.Carbon bricks are also installed as lining in tanks for making phosphoric acid because carbon has a very good resistance to acids.Wear resistant graphite plates are used as shaped bricks for the manufacture of fused cast corundum bricks.It must be mentioned that there is no international standard for carbon and graphite refractories and properties depend only on the manufacturer according to the request of consumer.3.Carbon containing materialsGraphite and carbon also are used in combination with other refractory materials to form a composite suitable for certain applications.The importance of carbon additions can be seen in the wear reduction by reducing infiltration depth and in the bond of the unfired bricks.In addition,thermal shockresistance is improved by increasing thermal conductivity and decreasing thermal expansion.29)The brickbond of unfired products in a cok ed operation state is based on the adhesion between the coke lattice and refractory particles as well as on the adhesion within the coke lattice with partial direct atomic bonds,secondary valence bonds and van der Waal forces.The infiltration depth is changed substantially by carbon from centimeters to millimeters.Consequently,the wear mechanism of the bricks is changed drastically.Two factors are responsible for this:(1)The reduction of iron oxide in the liquid infiltration by metal.The eutectic temperature of the infiltrate is increased to its solidification point(with CaO/SiO2molar 2if infiltrate contains FeO).(2)Nonwetting between the oxide infiltrate and carbon of the brickat a contact angle f 90 (with CaO/SiO2molar 2if infiltrate doesn't contain FeO).In addition to the FeO content,the CaO/SiO2molar ratio is a decisive in determining which of the two effects take place. The CaO/SiO2molar ratio regulates itself on the hot face side directly in the front of the carboncontaining brickzone.With magnesia and magnesiadoloma brick,the CaO/SiO2molar ratio always stays 2because of the high CaO content in the brick.Consequently,the reducing effect is always active with these bricks if the slags contain FeO.For magnesia bricks, however,this ratio can drop below 2as a result of the different precipitation during infiltration.The iron ions of the infiltrate are absorbed by the periclase(MgO in accordance with the chemical balance within the solution).Consequently, the melt losses iron before it reaches the carbon in the brick. Due to the CaO/SiO2molar ratio dropping 2,the infiltrate remains liquid and agile despite its loss of iron.In this case, the nonwetting effect prevails.The same applies for slags without FeO.The decisive factor for effective utilization and application of Ccontaining bricks is the burnout speed of carbon.In pitch or resinbonded bricks,a cracked carbon lattice forms the brickbond.This means that carbon burnout leads to a decisive bond loss.Consequently,Ccontaining bricks can and should be used where reducing gases,that is a furnace atmosphere with low oxygen partial pressure,are predominant.Examples are converters,electric arc furnaces or the metallurgical ladle.In order to lower speed,additives for retarding oxidation are also used.Carbon containing materials are divided into carbon based basic refractories and carbon based non basic refractories. Each type also can be classified according to the binders used. This means that the carbon to refractories carry out via different techniques to manufacture these types.3.1ManufacturingThe brick s or the block s of these types of refractories are manufactured by grinding the raw materials,sieving,classification,mixing to batches depending on the desired property values,heating to approximately100 200 C depending on the type of bond,and mixing with binder to get the socalled g green batch h or g green mixture.h However,the bricks bonded with synthetic resin are manufactured cold or hot 100 C with liquid and a hardener.Next the mix is shaped. Vacuum vibration equipment,die presses,extrusion presses, isostatic presses,hot pressing and tempering,and ramming equipment are used to form the batch/mixture into the desired shape.After shaping,the socalled g green h shape is subjected to a firing process up to approx.1200 C.The binder converts to coke.It is possible to accomplish subsequent densification and compaction.It is possible to accomplish subsequent densification and compaction by impregnating the blocks with impregnation agents,which are similar to the binder in regard to their compaction.The impregnation agent,which has entered the pores,is also converted to coke during further firing cycle.3.2Bonding materialsThe binding materials for carbon based refractory materials should have an ash content as low as possible as well as a high yield.Tars,coaltars or coaltar pitches are the commonest types of materials used as carbon sources and binders for refractory bricks.They have long been used in practice.The physical properties of the tar or pitch influence the processing behavior greatly during manufacture.Conversely,the choice of binder is also determined by the particular processes in use.30)The softening point of the residual binder should not be exceeded prior to carbonization for any given bricks to prevent spalling.31)Because of the potential health hazards in the handling of such materials and the evolution of hazardouds pyrolysis products,there is a tendency to use polymers to replace tars, coal tars and coaltar pitches.32) 35)Phenolic resins,both novalacks and resols are favored because they are or can become thermosetting and because they can be pyrolysed during coking to achieve a high carbon yield.In addition to favorable pyrolysis and carbonization behavior,they are available in various forms,such as solutions,powder resins,520Carbon Based Refractoriessolid materials,and melts.They also serve as binders and impregnating agents for carbonaceous materials and refractory products.Synthetic resin bonded bricks offer the following basic advantages:36),37)(1)Their production and processing is environmentally acceptable.(2)Their production by means of the cold mixing method conserve energy.(3)The products can be processed in uncured conditions.(4)The products have no plastic phase when heated up,in contrast to tarpitch binders.(5)The carbon content(more graphite or soot)can increased to augment resistance to abrasion and slag attack. The control in cure of the resins is very important factor where some resins tend to harden in a comparatively short time.This,in turn,reduces the time that mix can be retained before it must be shaped into bricks or other desired shapes. Lyer and Shah38)contributed in solving this problem by control in pH in the presence of a catalyst.During heating of this product in the operation state,the pitch form elementary carbon(coking)at300 600 C by pyrolysis in liquid state leading to a separation of the volatile constituents(cracking).29)Laminated carbon packages form with good structure at the hexagonal base plane.These carbon packages are easy to graphitize and possess good optical anisotropy.However,in the c direction the carbon planes stay shifted and twisted,with varying degree of distance,even at the highest operation temperature.This intense degree of onedimensional imperfection corresponds to a polycrystalline graphite lattice(the threedimensional graphite structure is not obtainable until 2000 C).In contrast to pitch,the pyrolysis of phenolic resins,which are synthetic polycondensation products occur in solid state.The strong space interlacement of the molecule chains and,as consequence,missing agility prevents an oriented deposit of hexagonal carbon layers.A poorly arranged and strongly interlaced lattic is the result.This prevents gliding and cleavage.Therefore,these cokes are hard and very sensitive to oxidation due to the large inner surface.39)Phenolic resin has been widely used for its excellence kneading properties,molding properties and economy for carbon containing bricks.Although this binder has superior properties but it has some drawbacks.Firstly,a phenolic resin generates gases such as water,hydrogen,ethylene,phenol,cresol and xylenol when carbonized in temperature range of from 350 650 C causing air pollution and odor,etc.40) 42)Secondly, where a phenolic resin is used as a binder,the resulting structure is dense and has insufficient open cells.Therefore,the structure is liable to destruction due to the evolution of decomposition gas on heating.Thirdly,carbon produced from a phenolic resin is a glassy carbon inferior in resistance to spalling.Although the phenolic resin has a high residual carbon on burning,the resulting products have poor spalling resistance.Yamamura et al.43)proposed the using saccharified starch of a nonaromatic organic highmolecular compound to overcome the disadvantages of the pitchbonded type and using of a hexahydric alcohol as well as the first to the third drawbacks associating the use of a phenolic resin.3.3Carboncontaining basic materials3.3.1Carbon containing magnesia refractoriesThe evolution and use of magnesia refractories in combination with carbon started over forty years ago,in the early 1950's,with pitch bonded dolomite refractories,developed primarily for the basic oxygen furnace.In these early days, some of these linings in the basic oxygen furnace lasted only 100heats,often not giving sufficient time to reline the second vessel in a two furnace shop.44)Very measurable improvement came when magnesia fines were used in conjunction with the dolomite coarse fractions bonded with pitch.Further improvements came with the all magnesia pitch bonded brick.In the1970's the burned and impregna ted ma gnesia brickwith finite pore size beca me the standard for the charge pad and other high wear areas,starting the beginning of the zoned lining for basic oxygen furnaces.45)About that time magnesia purity became a factor and a special low boron96÷magnesia grain having a lime to silica ratio of2to3F1was used extensively.The1980's saw the development of resin bonded magnesiagraphite,first with higher carbon content and then with the addition of antioxidants to preserve the carbon content.46),47) Recently fused magnesia grain,sintered magnesia with larger crystallite size,and very high purity sintered magnesia were introduced to further improve the corrosion resistance.48) In addition to conventional pitch and resin bonded and burned and impregnated magnesia brick,the following three types of ma gnesia ca rbon bricka re a va ila ble on the ma rk et.«The first series contains regular sintered magnesia(97÷Mg0)with medium quality graphite(95÷C).«The second contains high purity sintered magnesia(99÷Mg0)with high purity graphite(99÷C).«The third contains high purity sintered magnesia with high purity graphite plus antioxidants.Magnesia carbon refractories are classified into three types according to the carbon:(1)Fired carboncontaining magnesia bricks( 2÷C),(2)Carbonbonded magnesia bricks( 7÷C)49)and(3)Carbonbonded magnesiacarbon bricks( 7÷C)50). The third one of refractory type is best suited classify on the light of binder to two types as following:(1)Bricks with pitch bonded(with max.15÷C),partially with subsequent pitch impregnation under vacuum or secondary for special cases with antioxidants,and,(2)Brick s with synthetic resin bond up to25÷C)often with added antioxidants(Al,Si,AlSi,Mg,AlMg,B4C among others in powder form).3.3.1.1Production technologyMgO C bricks are manufactured from high purity MgO clinker i.e.natural,sea water and electrofused magnesia as well as flaky graphite with carbon content of86 99÷,carbon bla ckwhether therma l or furna ce with na tura l ga s or oil base,and coke binders whether pitch or synthetic resins for unfired products.In these types,a high chemothermal stability is required from magnesia in bricks containing carbon.This means that a CaO/SiO2molar ratio of magnesia should be 2 as well as possibly slight contents of B2O3and SiO2which form melts;furthermore,little Al2O3and Fe2O3.In addition, periclase boundary surface should be a negligibly reactive due to low apparent porosity and large crystals.51),52)Fired carboncontaining magnesia bricks are manufactured by placing the fired magnesia bricks under vacuum at150 200 C and impregnated with pitch or resins.In this process,it is not possible to obtain more than2÷residual carbon. Repeated impregnation along with intermediate coking or the separation of carbon out of furfuryl alcohol,for example,to increase the carbon content,have not proven to be economically feasible.Concerning to the properties,these bricks only differ from fired magnesia bricks in regard to infiltrationretarding effect of carbon.This has a decisive influence on the wear behavior but is hardly noticed when comparing test or inspection value.Table2.Properties of Carbon Containing Magnesia and Magnesia Carbon BricksTable3.Thermo Mechanical Properties of Carbon Containing Magnesia and Magnesia Carbon Bricks521Emad Mohamed M.EWAIS Journal of the Ceramic Society of Japan 112[10]2004The bricks are distinguished by superb erosion resistance due to the firing of the brick.However,the thermal shock resistance is only moderate (See Tables 2and 3).Carbonbonded magnesia brick (pitch impregnated )is manufactured by mixing magnesia and pitch at 100 200 C,these bricks are shaped while still warm and tempered at 250 350 C to obtain sufficient hot strength.In addition to tempering and using pitch instead of tar for improving the carbon bond,carbon black is added,dehydrogenation agents are used and pitches impregnates under vacuum are further step.Carbon black can be dispersed in pitch in such way that it will greatly strengthen the coke bond.Dehydrogenation agents such as sulfur also increase the output of carbon.N.B.1 Hard coal pitch has the best performance /cost relativeof all coked binders.2 Phenolic resin is not only used as binder for magnesiacarbon brickswith 7÷C but also sometimes for magnesia bricks above 5÷C.Carbonbonded magnesia carbon bricks are characterized by residual carbon content of more than 7÷.The obtained high content of residual carbon can't be reached even by addition of graphite.Carbonbonded magnesia carbon bricks with pitch bonded are manufactured by hot pressing and tempering at 250 350 C.The bricks bonded with synthetic resin are manufactured cold or hot at temperature less than 100 C with liquid phenolic resol or phenolic novalac solutions and a hardener.Next,the binders are hardened at 120 200 C.Due to interlacing,this ensures formation of a highly molecular and nonmeltable resite lattice.Carbonbonded magnesia carbon bricks having high properties in respect of resistance to thermal,structural spalling,slag resistance and thermal shock resistance,etc.It is manufactured from 60 97÷sintered magnesia of bulk specific gravity about 3.4and 3 40÷carbonaceous materials and a carbon bonding formative agent 53)for applications in the converter.The effect of impurities in magnesia upon the reaction between magnesia clinker and carbon was estimated by measuring the weight loss of MgO specimen reacted with graphite at 1500 1750 C.54),55)It was found that the reaction between the MgO clinker and the carbon was affected by the chemical composition of the clinker rather than by its crystal size.。
Engineered O-Rings Catalog ORD 5710 美国Parker O-Rin
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History of infrared detectorsA.ROGALSKI*Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str.,00–908 Warsaw, PolandThis paper overviews the history of infrared detector materials starting with Herschel’s experiment with thermometer on February11th,1800.Infrared detectors are in general used to detect,image,and measure patterns of the thermal heat radia−tion which all objects emit.At the beginning,their development was connected with thermal detectors,such as ther−mocouples and bolometers,which are still used today and which are generally sensitive to all infrared wavelengths and op−erate at room temperature.The second kind of detectors,called the photon detectors,was mainly developed during the20th Century to improve sensitivity and response time.These detectors have been extensively developed since the1940’s.Lead sulphide(PbS)was the first practical IR detector with sensitivity to infrared wavelengths up to~3μm.After World War II infrared detector technology development was and continues to be primarily driven by military applications.Discovery of variable band gap HgCdTe ternary alloy by Lawson and co−workers in1959opened a new area in IR detector technology and has provided an unprecedented degree of freedom in infrared detector design.Many of these advances were transferred to IR astronomy from Departments of Defence ter on civilian applications of infrared technology are frequently called“dual−use technology applications.”One should point out the growing utilisation of IR technologies in the civilian sphere based on the use of new materials and technologies,as well as the noticeable price decrease in these high cost tech−nologies.In the last four decades different types of detectors are combined with electronic readouts to make detector focal plane arrays(FPAs).Development in FPA technology has revolutionized infrared imaging.Progress in integrated circuit design and fabrication techniques has resulted in continued rapid growth in the size and performance of these solid state arrays.Keywords:thermal and photon detectors, lead salt detectors, HgCdTe detectors, microbolometers, focal plane arrays.Contents1.Introduction2.Historical perspective3.Classification of infrared detectors3.1.Photon detectors3.2.Thermal detectors4.Post−War activity5.HgCdTe era6.Alternative material systems6.1.InSb and InGaAs6.2.GaAs/AlGaAs quantum well superlattices6.3.InAs/GaInSb strained layer superlattices6.4.Hg−based alternatives to HgCdTe7.New revolution in thermal detectors8.Focal plane arrays – revolution in imaging systems8.1.Cooled FPAs8.2.Uncooled FPAs8.3.Readiness level of LWIR detector technologies9.SummaryReferences 1.IntroductionLooking back over the past1000years we notice that infra−red radiation(IR)itself was unknown until212years ago when Herschel’s experiment with thermometer and prism was first reported.Frederick William Herschel(1738–1822) was born in Hanover,Germany but emigrated to Britain at age19,where he became well known as both a musician and an astronomer.Herschel became most famous for the discovery of Uranus in1781(the first new planet found since antiquity)in addition to two of its major moons,Tita−nia and Oberon.He also discovered two moons of Saturn and infrared radiation.Herschel is also known for the twenty−four symphonies that he composed.W.Herschel made another milestone discovery–discov−ery of infrared light on February11th,1800.He studied the spectrum of sunlight with a prism[see Fig.1in Ref.1],mea−suring temperature of each colour.The detector consisted of liquid in a glass thermometer with a specially blackened bulb to absorb radiation.Herschel built a crude monochromator that used a thermometer as a detector,so that he could mea−sure the distribution of energy in sunlight and found that the highest temperature was just beyond the red,what we now call the infrared(‘below the red’,from the Latin‘infra’–be−OPTO−ELECTRONICS REVIEW20(3),279–308DOI: 10.2478/s11772−012−0037−7*e−mail: rogan@.pllow)–see Fig.1(b)[2].In April 1800he reported it to the Royal Society as dark heat (Ref.1,pp.288–290):Here the thermometer No.1rose 7degrees,in 10minu−tes,by an exposure to the full red coloured rays.I drew back the stand,till the centre of the ball of No.1was just at the vanishing of the red colour,so that half its ball was within,and half without,the visible rays of theAnd here the thermometerin 16minutes,degrees,when its centre was inch out of the raysof the sun.as had a rising of 9de−grees,and here the difference is almost too trifling to suppose,that latter situation of the thermometer was much beyond the maximum of the heating power;while,at the same time,the experiment sufficiently indi−cates,that the place inquired after need not be looked for at a greater distance.Making further experiments on what Herschel called the ‘calorific rays’that existed beyond the red part of the spec−trum,he found that they were reflected,refracted,absorbed and transmitted just like visible light [1,3,4].The early history of IR was reviewed about 50years ago in three well−known monographs [5–7].Many historical information can be also found in four papers published by Barr [3,4,8,9]and in more recently published monograph [10].Table 1summarises the historical development of infrared physics and technology [11,12].2.Historical perspectiveFor thirty years following Herschel’s discovery,very little progress was made beyond establishing that the infrared ra−diation obeyed the simplest laws of optics.Slow progress inthe study of infrared was caused by the lack of sensitive and accurate detectors –the experimenters were handicapped by the ordinary thermometer.However,towards the second de−cade of the 19th century,Thomas Johann Seebeck began to examine the junction behaviour of electrically conductive materials.In 1821he discovered that a small electric current will flow in a closed circuit of two dissimilar metallic con−ductors,when their junctions are kept at different tempera−tures [13].During that time,most physicists thought that ra−diant heat and light were different phenomena,and the dis−covery of Seebeck indirectly contributed to a revival of the debate on the nature of heat.Due to small output vol−tage of Seebeck’s junctions,some μV/K,the measurement of very small temperature differences were prevented.In 1829L.Nobili made the first thermocouple and improved electrical thermometer based on the thermoelectric effect discovered by Seebeck in 1826.Four years later,M.Melloni introduced the idea of connecting several bismuth−copper thermocouples in series,generating a higher and,therefore,measurable output voltage.It was at least 40times more sensitive than the best thermometer available and could de−tect the heat from a person at a distance of 30ft [8].The out−put voltage of such a thermopile structure linearly increases with the number of connected thermocouples.An example of thermopile’s prototype invented by Nobili is shown in Fig.2(a).It consists of twelve large bismuth and antimony elements.The elements were placed upright in a brass ring secured to an adjustable support,and were screened by a wooden disk with a 15−mm central aperture.Incomplete version of the Nobili−Melloni thermopile originally fitted with the brass cone−shaped tubes to collect ra−diant heat is shown in Fig.2(b).This instrument was much more sensi−tive than the thermometers previously used and became the most widely used detector of IR radiation for the next half century.The third member of the trio,Langley’s bolometer appea−red in 1880[7].Samuel Pierpont Langley (1834–1906)used two thin ribbons of platinum foil connected so as to form two arms of a Wheatstone bridge (see Fig.3)[15].This instrument enabled him to study solar irradiance far into its infrared region and to measure theintensityof solar radia−tion at various wavelengths [9,16,17].The bolometer’s sen−History of infrared detectorsFig.1.Herschel’s first experiment:A,B –the small stand,1,2,3–the thermometers upon it,C,D –the prism at the window,E –the spec−trum thrown upon the table,so as to bring the last quarter of an inch of the read colour upon the stand (after Ref.1).InsideSir FrederickWilliam Herschel (1738–1822)measures infrared light from the sun– artist’s impression (after Ref. 2).Fig.2.The Nobili−Meloni thermopiles:(a)thermopile’s prototype invented by Nobili (ca.1829),(b)incomplete version of the Nobili−−Melloni thermopile (ca.1831).Museo Galileo –Institute and Museum of the History of Science,Piazza dei Giudici 1,50122Florence, Italy (after Ref. 14).Table 1. Milestones in the development of infrared physics and technology (up−dated after Refs. 11 and 12)Year Event1800Discovery of the existence of thermal radiation in the invisible beyond the red by W. HERSCHEL1821Discovery of the thermoelectric effects using an antimony−copper pair by T.J. SEEBECK1830Thermal element for thermal radiation measurement by L. NOBILI1833Thermopile consisting of 10 in−line Sb−Bi thermal pairs by L. NOBILI and M. MELLONI1834Discovery of the PELTIER effect on a current−fed pair of two different conductors by J.C. PELTIER1835Formulation of the hypothesis that light and electromagnetic radiation are of the same nature by A.M. AMPERE1839Solar absorption spectrum of the atmosphere and the role of water vapour by M. MELLONI1840Discovery of the three atmospheric windows by J. HERSCHEL (son of W. HERSCHEL)1857Harmonization of the three thermoelectric effects (SEEBECK, PELTIER, THOMSON) by W. THOMSON (Lord KELVIN)1859Relationship between absorption and emission by G. KIRCHHOFF1864Theory of electromagnetic radiation by J.C. MAXWELL1873Discovery of photoconductive effect in selenium by W. SMITH1876Discovery of photovoltaic effect in selenium (photopiles) by W.G. ADAMS and A.E. DAY1879Empirical relationship between radiation intensity and temperature of a blackbody by J. STEFAN1880Study of absorption characteristics of the atmosphere through a Pt bolometer resistance by S.P. LANGLEY1883Study of transmission characteristics of IR−transparent materials by M. MELLONI1884Thermodynamic derivation of the STEFAN law by L. BOLTZMANN1887Observation of photoelectric effect in the ultraviolet by H. HERTZ1890J. ELSTER and H. GEITEL constructed a photoemissive detector consisted of an alkali−metal cathode1894, 1900Derivation of the wavelength relation of blackbody radiation by J.W. RAYEIGH and W. WIEN1900Discovery of quantum properties of light by M. PLANCK1903Temperature measurements of stars and planets using IR radiometry and spectrometry by W.W. COBLENTZ1905 A. EINSTEIN established the theory of photoelectricity1911R. ROSLING made the first television image tube on the principle of cathode ray tubes constructed by F. Braun in 18971914Application of bolometers for the remote exploration of people and aircrafts ( a man at 200 m and a plane at 1000 m)1917T.W. CASE developed the first infrared photoconductor from substance composed of thallium and sulphur1923W. SCHOTTKY established the theory of dry rectifiers1925V.K. ZWORYKIN made a television image tube (kinescope) then between 1925 and 1933, the first electronic camera with the aid of converter tube (iconoscope)1928Proposal of the idea of the electro−optical converter (including the multistage one) by G. HOLST, J.H. DE BOER, M.C. TEVES, and C.F. VEENEMANS1929L.R. KOHLER made a converter tube with a photocathode (Ag/O/Cs) sensitive in the near infrared1930IR direction finders based on PbS quantum detectors in the wavelength range 1.5–3.0 μm for military applications (GUDDEN, GÖRLICH and KUTSCHER), increased range in World War II to 30 km for ships and 7 km for tanks (3–5 μm)1934First IR image converter1939Development of the first IR display unit in the United States (Sniperscope, Snooperscope)1941R.S. OHL observed the photovoltaic effect shown by a p−n junction in a silicon1942G. EASTMAN (Kodak) offered the first film sensitive to the infrared1947Pneumatically acting, high−detectivity radiation detector by M.J.E. GOLAY1954First imaging cameras based on thermopiles (exposure time of 20 min per image) and on bolometers (4 min)1955Mass production start of IR seeker heads for IR guided rockets in the US (PbS and PbTe detectors, later InSb detectors for Sidewinder rockets)1957Discovery of HgCdTe ternary alloy as infrared detector material by W.D. LAWSON, S. NELSON, and A.S. YOUNG1961Discovery of extrinsic Ge:Hg and its application (linear array) in the first LWIR FLIR systems1965Mass production start of IR cameras for civil applications in Sweden (single−element sensors with optomechanical scanner: AGA Thermografiesystem 660)1970Discovery of charge−couple device (CCD) by W.S. BOYLE and G.E. SMITH1970Production start of IR sensor arrays (monolithic Si−arrays: R.A. SOREF 1968; IR−CCD: 1970; SCHOTTKY diode arrays: F.D.SHEPHERD and A.C. YANG 1973; IR−CMOS: 1980; SPRITE: T. ELIOTT 1981)1975Lunch of national programmes for making spatially high resolution observation systems in the infrared from multielement detectors integrated in a mini cooler (so−called first generation systems): common module (CM) in the United States, thermal imaging commonmodule (TICM) in Great Britain, syteme modulaire termique (SMT) in France1975First In bump hybrid infrared focal plane array1977Discovery of the broken−gap type−II InAs/GaSb superlattices by G.A. SAI−HALASZ, R. TSU, and L. ESAKI1980Development and production of second generation systems [cameras fitted with hybrid HgCdTe(InSb)/Si(readout) FPAs].First demonstration of two−colour back−to−back SWIR GaInAsP detector by J.C. CAMPBELL, A.G. DENTAI, T.P. LEE,and C.A. BURRUS1985Development and mass production of cameras fitted with Schottky diode FPAs (platinum silicide)1990Development and production of quantum well infrared photoconductor (QWIP) hybrid second generation systems1995Production start of IR cameras with uncooled FPAs (focal plane arrays; microbolometer−based and pyroelectric)2000Development and production of third generation infrared systemssitivity was much greater than that of contemporary thermo−piles which were little improved since their use by Melloni. Langley continued to develop his bolometer for the next20 years(400times more sensitive than his first efforts).His latest bolometer could detect the heat from a cow at a dis−tance of quarter of mile [9].From the above information results that at the beginning the development of the IR detectors was connected with ther−mal detectors.The first photon effect,photoconductive ef−fect,was discovered by Smith in1873when he experimented with selenium as an insulator for submarine cables[18].This discovery provided a fertile field of investigation for several decades,though most of the efforts were of doubtful quality. By1927,over1500articles and100patents were listed on photosensitive selenium[19].It should be mentioned that the literature of the early1900’s shows increasing interest in the application of infrared as solution to numerous problems[7].A special contribution of William Coblenz(1873–1962)to infrared radiometry and spectroscopy is marked by huge bib−liography containing hundreds of scientific publications, talks,and abstracts to his credit[20,21].In1915,W.Cob−lentz at the US National Bureau of Standards develops ther−mopile detectors,which he uses to measure the infrared radi−ation from110stars.However,the low sensitivity of early in−frared instruments prevented the detection of other near−IR sources.Work in infrared astronomy remained at a low level until breakthroughs in the development of new,sensitive infrared detectors were achieved in the late1950’s.The principle of photoemission was first demonstrated in1887when Hertz discovered that negatively charged par−ticles were emitted from a conductor if it was irradiated with ultraviolet[22].Further studies revealed that this effect could be produced with visible radiation using an alkali metal electrode [23].Rectifying properties of semiconductor−metal contact were discovered by Ferdinand Braun in1874[24],when he probed a naturally−occurring lead sulphide(galena)crystal with the point of a thin metal wire and noted that current flowed freely in one direction only.Next,Jagadis Chandra Bose demonstrated the use of galena−metal point contact to detect millimetre electromagnetic waves.In1901he filed a U.S patent for a point−contact semiconductor rectifier for detecting radio signals[25].This type of contact called cat’s whisker detector(sometimes also as crystal detector)played serious role in the initial phase of radio development.How−ever,this contact was not used in a radiation detector for the next several decades.Although crystal rectifiers allowed to fabricate simple radio sets,however,by the mid−1920s the predictable performance of vacuum−tubes replaced them in most radio applications.The period between World Wars I and II is marked by the development of photon detectors and image converters and by emergence of infrared spectroscopy as one of the key analytical techniques available to chemists.The image con−verter,developed on the eve of World War II,was of tre−mendous interest to the military because it enabled man to see in the dark.The first IR photoconductor was developed by Theodore W.Case in1917[26].He discovered that a substance com−posed of thallium and sulphur(Tl2S)exhibited photocon−ductivity.Supported by the US Army between1917and 1918,Case adapted these relatively unreliable detectors for use as sensors in an infrared signalling device[27].The pro−totype signalling system,consisting of a60−inch diameter searchlight as the source of radiation and a thallous sulphide detector at the focus of a24−inch diameter paraboloid mir−ror,sent messages18miles through what was described as ‘smoky atmosphere’in1917.However,instability of resis−tance in the presence of light or polarizing voltage,loss of responsivity due to over−exposure to light,high noise,slug−gish response and lack of reproducibility seemed to be inhe−rent weaknesses.Work was discontinued in1918;commu−nication by the detection of infrared radiation appeared dis−tinctly ter Case found that the addition of oxygen greatly enhanced the response [28].The idea of the electro−optical converter,including the multistage one,was proposed by Holst et al.in1928[29]. The first attempt to make the converter was not successful.A working tube consisted of a photocathode in close proxi−mity to a fluorescent screen was made by the authors in 1934 in Philips firm.In about1930,the appearance of the Cs−O−Ag photo−tube,with stable characteristics,to great extent discouraged further development of photoconductive cells until about 1940.The Cs−O−Ag photocathode(also called S−1)elabo−History of infrared detectorsFig.3.Longley’s bolometer(a)composed of two sets of thin plati−num strips(b),a Wheatstone bridge,a battery,and a galvanometer measuring electrical current (after Ref. 15 and 16).rated by Koller and Campbell[30]had a quantum efficiency two orders of magnitude above anything previously studied, and consequently a new era in photoemissive devices was inaugurated[31].In the same year,the Japanese scientists S. Asao and M.Suzuki reported a method for enhancing the sensitivity of silver in the S−1photocathode[32].Consisted of a layer of caesium on oxidized silver,S−1is sensitive with useful response in the near infrared,out to approxi−mately1.2μm,and the visible and ultraviolet region,down to0.3μm.Probably the most significant IR development in the United States during1930’s was the Radio Corporation of America(RCA)IR image tube.During World War II, near−IR(NIR)cathodes were coupled to visible phosphors to provide a NIR image converter.With the establishment of the National Defence Research Committee,the develop−ment of this tube was accelerated.In1942,the tube went into production as the RCA1P25image converter(see Fig.4).This was one of the tubes used during World War II as a part of the”Snooperscope”and”Sniperscope,”which were used for night observation with infrared sources of illumination.Since then various photocathodes have been developed including bialkali photocathodes for the visible region,multialkali photocathodes with high sensitivity ex−tending to the infrared region and alkali halide photocatho−des intended for ultraviolet detection.The early concepts of image intensification were not basically different from those today.However,the early devices suffered from two major deficiencies:poor photo−cathodes and poor ter development of both cathode and coupling technologies changed the image in−tensifier into much more useful device.The concept of image intensification by cascading stages was suggested independently by number of workers.In Great Britain,the work was directed toward proximity focused tubes,while in the United State and in Germany–to electrostatically focused tubes.A history of night vision imaging devices is given by Biberman and Sendall in monograph Electro−Opti−cal Imaging:System Performance and Modelling,SPIE Press,2000[10].The Biberman’s monograph describes the basic trends of infrared optoelectronics development in the USA,Great Britain,France,and Germany.Seven years later Ponomarenko and Filachev completed this monograph writ−ing the book Infrared Techniques and Electro−Optics in Russia:A History1946−2006,SPIE Press,about achieve−ments of IR techniques and electrooptics in the former USSR and Russia [33].In the early1930’s,interest in improved detectors began in Germany[27,34,35].In1933,Edgar W.Kutzscher at the University of Berlin,discovered that lead sulphide(from natural galena found in Sardinia)was photoconductive and had response to about3μm.B.Gudden at the University of Prague used evaporation techniques to develop sensitive PbS films.Work directed by Kutzscher,initially at the Uni−versity of Berlin and later at the Electroacustic Company in Kiel,dealt primarily with the chemical deposition approach to film formation.This work ultimately lead to the fabrica−tion of the most sensitive German detectors.These works were,of course,done under great secrecy and the results were not generally known until after1945.Lead sulphide photoconductors were brought to the manufacturing stage of development in Germany in about1943.Lead sulphide was the first practical infrared detector deployed in a variety of applications during the war.The most notable was the Kiel IV,an airborne IR system that had excellent range and which was produced at Carl Zeiss in Jena under the direction of Werner K. Weihe [6].In1941,Robert J.Cashman improved the technology of thallous sulphide detectors,which led to successful produc−tion[36,37].Cashman,after success with thallous sulphide detectors,concentrated his efforts on lead sulphide detec−tors,which were first produced in the United States at Northwestern University in1944.After World War II Cash−man found that other semiconductors of the lead salt family (PbSe and PbTe)showed promise as infrared detectors[38]. The early detector cells manufactured by Cashman are shown in Fig. 5.Fig.4.The original1P25image converter tube developed by the RCA(a).This device measures115×38mm overall and has7pins.It opera−tion is indicated by the schematic drawing (b).After1945,the wide−ranging German trajectory of research was essentially the direction continued in the USA, Great Britain and Soviet Union under military sponsorship after the war[27,39].Kutzscher’s facilities were captured by the Russians,thus providing the basis for early Soviet detector development.From1946,detector technology was rapidly disseminated to firms such as Mullard Ltd.in Southampton,UK,as part of war reparations,and some−times was accompanied by the valuable tacit knowledge of technical experts.E.W.Kutzscher,for example,was flown to Britain from Kiel after the war,and subsequently had an important influence on American developments when he joined Lockheed Aircraft Co.in Burbank,California as a research scientist.Although the fabrication methods developed for lead salt photoconductors was usually not completely under−stood,their properties are well established and reproducibi−lity could only be achieved after following well−tried reci−pes.Unlike most other semiconductor IR detectors,lead salt photoconductive materials are used in the form of polycrys−talline films approximately1μm thick and with individual crystallites ranging in size from approximately0.1–1.0μm. They are usually prepared by chemical deposition using empirical recipes,which generally yields better uniformity of response and more stable results than the evaporative methods.In order to obtain high−performance detectors, lead chalcogenide films need to be sensitized by oxidation. The oxidation may be carried out by using additives in the deposition bath,by post−deposition heat treatment in the presence of oxygen,or by chemical oxidation of the film. The effect of the oxidant is to introduce sensitizing centres and additional states into the bandgap and thereby increase the lifetime of the photoexcited holes in the p−type material.3.Classification of infrared detectorsObserving a history of the development of the IR detector technology after World War II,many materials have been investigated.A simple theorem,after Norton[40],can be stated:”All physical phenomena in the range of about0.1–1 eV will be proposed for IR detectors”.Among these effects are:thermoelectric power(thermocouples),change in elec−trical conductivity(bolometers),gas expansion(Golay cell), pyroelectricity(pyroelectric detectors),photon drag,Jose−phson effect(Josephson junctions,SQUIDs),internal emis−sion(PtSi Schottky barriers),fundamental absorption(in−trinsic photodetectors),impurity absorption(extrinsic pho−todetectors),low dimensional solids[superlattice(SL), quantum well(QW)and quantum dot(QD)detectors], different type of phase transitions, etc.Figure6gives approximate dates of significant develop−ment efforts for the materials mentioned.The years during World War II saw the origins of modern IR detector tech−nology.Recent success in applying infrared technology to remote sensing problems has been made possible by the successful development of high−performance infrared de−tectors over the last six decades.Photon IR technology com−bined with semiconductor material science,photolithogra−phy technology developed for integrated circuits,and the impetus of Cold War military preparedness have propelled extraordinary advances in IR capabilities within a short time period during the last century [41].The majority of optical detectors can be classified in two broad categories:photon detectors(also called quantum detectors) and thermal detectors.3.1.Photon detectorsIn photon detectors the radiation is absorbed within the material by interaction with electrons either bound to lattice atoms or to impurity atoms or with free electrons.The observed electrical output signal results from the changed electronic energy distribution.The photon detectors show a selective wavelength dependence of response per unit incident radiation power(see Fig.8).They exhibit both a good signal−to−noise performance and a very fast res−ponse.But to achieve this,the photon IR detectors require cryogenic cooling.This is necessary to prevent the thermalHistory of infrared detectorsFig.5.Cashman’s detector cells:(a)Tl2S cell(ca.1943):a grid of two intermeshing comb−line sets of conducting paths were first pro−vided and next the T2S was evaporated over the grid structure;(b) PbS cell(ca.1945)the PbS layer was evaporated on the wall of the tube on which electrical leads had been drawn with aquadag(afterRef. 38).。
WPC_market_study_short_version
WPC/NFC Market Study 2014-03Wood-Plastic Composites (WPC) and Natural Fibre Composites (NFC):European and Global Markets 2012and Future Trends ArrayAuthors: Michael Carus, Dr. Asta Eder, Lara Dammer, Dr. Hans Korte, Lena Scholz,Roland Essel, Elke BreitmayerDownload this study and further nova market studies at:www.bio-based.eu/marketswww.bio-based.eu/markets WPC/NFC Market Study Biocomposites: 352,000 t of wood and Natural Fibre Composites produced in the European Union in 2012Authors: Michael Carus, Dr. Asta EderThe most important application sectors are construction (decking, siding and fencing) and automotive interior parts. Between 10 and 15% of the total European composite market is covered by Wood-Plastic Composites (WPC) and Natural Fibre Composites (NFC). The study was conducted by the nova-Institute (Germany) in cooperation with Asta Eder Composites Consulting (Austria/ Finland).This market report gives the first comprehensive and detailed picture of the use and amount of wood and natural fibre reinforced composites in the European bio-based economy. The analysis covers both Natural Fibre Composites and Wood-Plastic Composites in extrusion, injection and compression moulding in different sectors and for different applications.To establish a reliable basic dataset, the study draws on a survey conducted in 2013 among the WPC and NFC industry, producers and customers that belong to Asta Eder Composites Consulting’s and the nova-Institute’s comprehensive networks. The survey included company visits, personal and telephoneinterviews, as well as an email questionnaire. Table I: Production of biocomposites (WPC and NFC) in the European Union in 2012 (in tonnes) (nova 2014)WPC/NFC Market Study www.bio-based.eu/marketsThe rate of return was exceptionally high, especially for the WPC part of the study, with companies responsible for over 50% of extruded volume taking part in the survey. This means that the study covers roughly 65 European WPC extruding companies in 21 countries. In addition, more than 50 European companies using injection moulding, compression moulding and other processing technologies were included in the survey, as well as producers of WPC and NFC granulates.Total production of biocompositesTable I summarises the results of the survey, showing all Wood-Plastic Composites and Natural Fibre Composites produced in the European Union, including all sectors, applications and processing technologies. Decking and automotive are the most important application sectors for WPC, followed by siding and fencing. Only the automotive sector is relevant for Natural Fibre Composites (NFC) today. The share of WPC and NFC in the total composite market – including glass, carbon, wood and Natural Fibre Composites – is already an impressive 15%. Even higher shares are to be expected in the future: NFC are starting to enter other markets than just the automotive industry. WPC granulates for injection moulding are now produced and offered by global players and are becoming more attractive for clients that manufacture consumer goods, automotive and technical parts.With increasing polymer prices and expected incentives for bio-based products (the “bio-based economy” is one of the lead markets in Europe) this trend will go from strength to strength, resulting in two-digit growth and increasing market shares over the coming decade.Wood-Plastic Composites – Decking still dominant, but technical applications and consumer goods risingThe total volume of WPC production in Europe was 260,000 tonnes in 2012 (plus 92,000 tonnes of Natural Fibre Composites for the automotive industry, see Table I). The level of market penetration of bio-based composites varies between regions and from one application field to the next. Germany leads the way in terms of the number of actors and production figures. 45% (85,000 tonnes) of European WPC production for decking, fencing and other construction applications (190,000 tonnes) was extruded by 20 German companies.The typical production process in Europe is extrusion of a decking profile based on a PVC or PE matrix followed by PP. Increasing market penetration by WPC has meant that WPC volumes have risen strongly and Europe is now a mature WPC market. This study predicts growth, especially in the German-speaking world, on the back of a recovery in construction, particularly renovation, and a further increase in the WPC share of the highly competitive decking market. Also, variations of WPC decking models such as capped embossed solid profiles or garden fencing are on the rise across Europe.The development of the distribution across applications points to a state of affairs in which WPC is increasingly used for applications beyond the traditional ones like decking or automotive parts. For example, WPC is increasingly used to produce furniture, technical parts, consumer goods and household electronics, using injection moulding and other non-extrusion processes. Also, new production methods are being developed for the extrusion of broad WPC boards.www.bio-based.eu/markets WPC/NFC Market StudyFigure I shows the various application fields of WPC produced in Europe. The decking market leads the way with 67% (mainly extrusion), followed by automotive interior parts with 23% (mainly compression moulding and sheet extrusion as well as thermoforming). Although they are still small, siding and fencing, along with technical applications (mainly extrusion), consumer goods and furniture (mainly injection moulding), are showing the highest percentage increases.In the face of rising plastic prices, WPC granulates are getting more and more attractive for injection moulding, and increasingly feature in European granulate suppliers’ product ranges. Three big paper companies released cellulose-based PP granulates for injection moulding between 2012 and 2013. They use a PP matrix with cellulose and have fibre shares of between 20 and 50% for new and interesting applications such as furniture, consumer goods and automotive parts.The report also gives an overview of the latest market developments in North-America, Asia and Russia, and provides an overview of, and a forecast for, the global WPC market. Worldwide WPC production will rise from 2.43 million tonnes in 2012 to 3.83 million tonnes in 2015. Although North America is still the world’s leading production region with 1.1 million tonnes, ahead of China (900,000 t) and Europe (260,000 t), it is expected that China (with 1.8 million t by then) will have overtaken North America (1.4 million t) by 2015. European production will grow by around 10% per year and reach 350,000 tonnes in 2015.The share of WPC decking in the North American decking market is once more on the up, after a period of housing crises and WPC quality problems that led to a shakeout of the top WPC producers.Figure I: Application fields of WPC in Europe in 2012 (Total production 260.000 tonnes, all production processes) (nova 2014)WPC/NFC Market Studywww.bio-based.eu/marketsFigure II: Use of wood and natural fibres for composites in the European automotive industry in 2012, including cotton and wood (total volume: 80,000 tonnes). “Others” are mainly jute, coir, sisal and abaca (nova 2014)In China, decking also has a larger market share than other WPC applications, mainly due to strong exports, although the domestic market has developed rapidly in recent times. China also has the largest window and door market in the world. Hence companies have lately started to produce commercial window frames using WPC, with approximately 40% wood fibre as a substitute for PVC in combination with aluminium. China produces a large variety of WPC for indoor applications. Another successful product is an extruded WPC door that is already produced by 30 companies.WPC and NFC in the automotive industryInterior parts for the automotive industry is by far the most dominant use of Natural Fibre Composites – other sectors such as consumer goods are still at a very early stage. In the automotive sector, Natural Fibre Composites have a clear focus on interior trims for high-value doors and dashboards. Wood-Plastic Composites are mainly used for rear shelves and trims for trunks and spare wheels, as well as in interior trims for doors.Figure II shows the total volume of 80,000 tonnes of different wood and natural fibres used in the 150,000 tonnes of composites for passenger cars and lorries that were produced in Europe in 2012 (90,000 tonnes of Natural Fibre Composites and 60,000 tonnes of WPC). Recycled cotton fibre composites are mainly used for the driver cabins of lorries.www.bio-based.eu/markets WPC/NFC Market StudyThe highest market shares are for wood (of European origin), recycled cotton (from the world market) and flax fibres (of European origin). The shares of kenaf (from Asia) and hemp fibres (European origin) show the largest increases in percentage terms since the last survey for the year 2005.Process-wise, compression moulding of wood and Natural Fibre Composites are an established and proven technique for the production of extensive, lightweight and high-class interior parts for mid-range and luxury cars. The advantages (lightweight construction, crash behaviour, deformation resistance, lamination ability and, depending on the overall concept, price) and disadvantages (limited shape and design forming, scraps, cost disadvantages in case of high part integration in construction parts) are well known. Process optimisations are in progress in order to reduce certain problems such as scraps and to recycle wastage.Since 2009, new improved compression-moulded parts have shown impressive weight-reduction characteristics. This goes some way to explaining the growing interest in new car models. Using the newest technology, it is now possible to get area weight down to 1,500 g/m2 (with thermoplastics) or even 1,000 g/m2 (with thermosets), which are outstanding properties when compared to pure plastics or glass fibre composites.Still small in volume but also strong in innovation: PP and cellulose-based granulates for injected-moulded parts were recently introduced onto the automotive market by big paper companies in Europe and the USA. 15.7 million passenger cars were produced in the EU in 2011, and an additional 2 million other motor vehicles (incl. trucks, transporters, motor bikes, etc.) were manufactured. Considering that 30,000 tonnes of natural fibres and another 30,000 tonnes of wood fibres were used in 15.7 million passenger cars, on average every passenger car in Europe contains 1.9 kg of natural fibres respectively 1.9 kg of wood fibres. Since the German automotive industry is the most important consumer of natural fibre parts within the European automotive sector and since natural fibres are more used in middle- and high-class cars, the figures of 1.9 kg for the European average and 3.6 kg for the German average match well.From a technical point of view, much higher volumes of WPC and NFC are possible. Vehicles have been successfully produced in series for years with considerably larger amounts: 20 kg of natural and wood fibres. Market developments also depend on the political framework: any incentives for the use of natural and wood fibres in the European automotive industry could help to extend the existing volumes of 30,000 t/year each for natural and wood fibres. Such a vision could lead to an increase by a factor of up to five, which would represent 150,000 t per year and fibre type; the technologies are ready to use. Biocomposites have great potential!WPC/NFC Market Study www.bio-based.eu/markets Outlook for WPC and NFC production in the EUuntil 2020As just discussed, the production and use of 150,000 tonnes biocomposites (using 80,000 tonnes of wood and natural fibres) in the automotive sector in 2012 could expand to over 600,000 tonnes of biocomposites in 2020, using 150,000 tonnes of wood and natural fibres each along with some recycled cotton. Yet this fast development will not take place if there are no major political incentives to increase the bio-based share of the materials used in cars. Without incentives we forecast that production will only increase to 200,000 tonnes.Huge percentage increases can also be expected for WPC and NFC granulates used in injection moulding for all kind of technical and consumer goods. With improved technical properties, lower prices and bigger suppliers capable of supporting their customers, we forecast a growth from the tiny amount of 15,000 tonnes in 2012 to 100,000 tonnes by 2020. Additional incentives might at least double the production. For NFC granulates we foresee only niche markets with specific demand, reaching 10% of the WPC granulate market or 10,000 t in 2020.Extruded WPC is now well established as a material for decking, fencing and facade elements. Its market share is still growing and should reach and surpass the level of tropical wood in most of the European countries by 2020. About 190,000 tonnes of WPC were produced in Europe for the construction sector in 2012 – and this will be surely increase to 400,000 t in 2020. Unlike other sectors, political incentives will have only a small impact, because WPC are positioned against other bio-based materials and not, as in automotive or consumer goods, pitched against petrochemical plastics. Nevertheless, the whole framework of bio-based economy including green material databases will also give impetusto WPC decking.Table II: Production of biocomposites (WPC and NFC) in the European Union in 2012 and forecast 2020 (in tonnes) (nova 2014)www.bio-based.eu/markets WPC/NFC Market Study The authors of the studyDipl.-Phys. Michael Carus – nova-Institut (Germany) physicist, founderand managing director of the nova-Institute, is working for over 15 yearsin the field of Bio-based Economy. This includes biomass feedstock, processes, bio-based chemistry, plastics, fibres and composites. The focus of his work are market analysis, techno-economic and ecological evaluation as well as the political and economic framework for bio-based processes and applications (“level playing field for industrial material use”). Since 2005, Michael Carus is managing director of the European Industrial Hemp Association (EIHA).Dr. rer. nat. Asta Eder – Asta EderComposites Consulting (Austria/Finland) is one of the leading marketexperts on bio-based plastics andcomposites, especially on Wood-Plastic Composites. Dr. Eder did her PhD-work on market opportunities of innovative wood composites (WPC and Thermowood) in the German speaking area. She has been conducting market research and consulting for the development of new bio-based composites and their applications for the last 15 years. Asta Eder Composites Consulting is located in Vienna, Austria. It specializes in consultation of WPC and wood composite markets; product development and launch; and marketing and sales. Since 2013 Dr. Eder also works at the nova-Institute in the field of standardisation and certification of Bio-based Composites and WPC.M.A. Pol. Lara Dammer– nova-Institute (Germany) studied PoliticalScience with a focus on sustainabledevelopment at Bonn University. Sheis a staff scientist in the field of policy and strategy at nova-Institute. Her main focus is on framework conditions for the material use of renewable resources, national and international resource and environmental policies as well as communication and dissemination. She is active in analysing hurdles and enablers for a bio-based economy in Germany and the EU. As project manager she is currently working on a master plan for the development of the national kenaf industry with the government of Malaysia.Dr. rer. nat. Hans Korte– PHKPolymertechnik GmbH (Germany)studied Forestry at HamburgUniversity and gained a PhD inBiochemistry before taking up a post with an international chemical company, for whom he carried out R&D work on cellulose, was Head of Technical Marketing of Director of Sales of geoplastics.Since 2000 he has worked in Wismar as a freelance consultant on process, material and product development for wood, fibres and composites. He initiates and coordinates national and international research projects, conducts market surveys and writes expert reports. In 2002 he set up, and has since run, PHK Polymertechnik GmbH in Wismar, a company that develops and markets new materials such as Rotowood, WPC for rotation sintering, and Nerolit, a hydrophobic, durable and thermally stable filling material forplastic composites.WPC/NFC Market Study www.bio-based.eu/marketsDipl.-Wirtsch.-Ing. Lena Scholz– nova-Institute (Germany)is anindustrial engineer with a focuson bio-based materials, especiallybioplastics and bio-composites. Her expertise includes detailed knowledge of the global bioplastics market and she is one of the authors of the Market Study on Bio-based Polymers. Together with Michael Carus she has observing status in the CEN Committee for bio-based products representing the European Industrial Hemp Association. Since 2014, Lena Scholz is project manager at Tecnaro GmbH.Dipl.-Umweltwiss. Roland Essel– nova-Institute (Germany)studiedenvironmental sciences at theUniversities of Trier, Edinburgh andKarlsruhe and graduated from the University of Trier in 2010 with a thesis about the eco-efficiency of economic sectors in Europe. He started his career as a consultant for Taurus Eco Consulting GmbH as well as a research assistant at the chair of environmental accounting at the University of Technology in Dresden. Since May 2011 Roland Essel is project manager at the nova-Institute GmbH and responsible for ecological evaluation and environmental resource management.. His field of expertise covers life cycle assessment (LCA), system analysis and modelling (simulation & scenario analysis) of environmental impacts.M.Sc. agr. econ. Elke Breitmayer– nova-Institute (Germany)studiedAgricultural Economics at theUniversity of Hohenheim, Germanywith a focus on resource economics and rural development.In 2010 she was awarded a PhD scholarship from the DFG (German Research Foundation). She worked on the assessment of environmental impacts in intensive agricultural systems in China and as a scientific assistant at the Food Security Center at the University of Hohenheim. Shejoined the nova-Institute in 2013.nova Market StudiesWood-Plastic Composites (WPC)and Natural Fibre Composites (NFC):European and Global Markets 2012 andFuture Trends 2014-03 – 1,000 €plus VAT Bio-based Polymers in the World –Capacities, Production and Applications:Status Quo and Trends towards 20202013-03 – 6,500€plus VATAvailable at www.bio-based.eu/marketswww.bio-based.eu/markets WPC/NFC Market Study Table of Content0 Executive summary (6)1 Definition of bio-based composites, WPCand NFC (10)2 WPC components: plastics, wood flourand fibres, and additives (11)2.1 Plastics (11)2.2 Wood (13)2.2.1 Wood fibres (13)2.2.2 Wood flour (13)2.2.3 Wood chips (13)2.2.4 Wood shavings (13)2.3 “Other fibres” used in WPC production (13)2.4 Additives (14)2.5 Raw material costs of WPC production (14)3 Standards, norms, certificates and labelsfor bio-based composites (15)3.1 Example for national support structures: USDABioPreferred® program (15)3.1.1 ASTM D6866 Test Methods to Determinethe Bio-based Carbon Content of MaterialsUsing Radiocarbon and Isotope Ratio MassSpectrometry (15)3.1.2 ASTM D7075-04 Standard Practice forEvaluating and Reporting EnvironmentalPerformance of Bio-based Products (16)3.2 The situation in Europe (16)3.2.1 EN 15534: Composites made from cellulose-based materials and thermoplastics (usuallycalled wood-polymer composites (WPC) ornatural fibre composites (NFC)) (16)3.2.2 CEN/TC411 – prEN 16575 Bio-based products .16 3.2.3 Bio-based labels in Europe (17)3.3 National (Germany, Austria and France) andEuropean WPC and NFC standards ..................173.3.1 VHI (Germany): Quality and Testing Specificationsfor Production Control for Terrace Deckingmade from Wood-Polymer Composites (17)3.3.2 Austrian standard: ÖNORM CEN / T S 15534 1-3 18 3.3.3 French standard: XP T25-501-2:2009-10Reinforcement fibres – Flax fibres for plasticscomposites (18)3.4 Certification of the sustainability of wood asa raw material – FSC and PEFC (18)3.5 New certification systems for sustainablebiomass (19)4 Extrusion and other processing technologiesof WPC (20)4.1 Extrusion (20)4.2 Compression moulding (20)4.3 Injection moulding (21)4.4 WPC profile extrusion (21)4.4.1 Counter-rotating twin-screw extruder (22)4.4.2 Co-rotating twin-screw extruder (22)4.4.3 Heating-cooling mixer / fluidizing-cooling mixercombination (22)4.5 Recent trends (22)4.5.1 Recent trends in WPC extrusion (22)4.5.2 Recent trends in injection moulding (24)5 WPC markets, application fields anddistribution channels in Europe in 2012 (25)5.1 Brief history of WPC in Europe (25)5.2 Wood-Plastic Composites market overview inEurope (25)5.3 WPC innovation trendsin Europe (27)5.4 European decking market trends in 2012 (29)5.5 Regional differences, decking markets anddistribution (29)The market study “Wood-Plastic Composites (WPC) and Natural Fibre Composites (NFC): European and Global Markets 2012 and Future Trends” gives the first comprehensive and detailed picture of the use and amount of wood and natural fibre reinforced composites in the European bio-based economy. The full report covers the following subjects on 84 pages:6 Global trends in Wood-Plastic Composites (32)6.1 Leading WPC regions: North America and China 32 6.2 International application fields for WPC (34)6.2.1 Materials and prices (34)6.2.2 The Chinese WPC market (35)6.2.3 The WPC market in Russia (36)7 Wood and natural fibre based granulatesfor injection moulding and extrusion (38)7.1 Market structure (38)7.2 Technical properties of WPC and NFC ininjection moulding (40)7.3 WPC and NFC for furnitue and consumergoods (42)7.4 Price ranges for WPC and NFC granulates (43)7.5 Main WPC and NFC granulate producer andsupplier (43)8 Production and consumption of naturalfibres worldwide (46)8.1 Overview: Worldwide consumptionof fibres (46)8.2 Natural fibres: cultivation, productionand prices (48)8.2.1 Jute (48)8.2.2 Kenaf (50)8.2.3 Hemp (51)8.2.4 Flax (54)8.2.5 Sisal (55)9 Use of wood and natural fibres in compositesfor the European automotive production inthe year 2012 and outlook (56)9.1 Natural fibres in the European automotiveproduction – volumes and market share (56)9.2 Which developments can be expected forfibres in the coming years? (58)9.2.1 Kenaf ...............................................................589.2.2 Hemp (58)9.2.3 Other natural fibres (58)9.2.4 Conclusion (59)9.3 Main applications of natural fibres inautomotive composites (59)9.4 Volume and shares of different productiontechniques (59)9.5 Natural fibres per passenger car (60)9.6 Future developments (61)9.6.1 Compression moulding – with good growthpotential in lightweight construction (61)9.6.2 PP natural fibre injection moulding – still asleeping giant or already a dead dwarf? (62)9.6.3 Extrusion and thermoforming (63)9.6.4 Other processing technologies (63)9.7 Political framework (64)10 Other Applications of Natural Fibres:Non-wovens, Geotextiles and Insulation (65)10.1 Non-wovens worldwide (65)10.2 Non-wovens in Asia (65)10.3 Geotextiles worldwide (66)10.4 Natural fibre insulation in Europe (67)11 Overview of life cycle assessments forWood-Plastic Composites and NaturalFibre Composites (69)11.1 Introduction to life cycle assessment (LCA) (69)11.2 Results from recent life cycle assessments (69)11.2.1 Production of natural fibres (69)11.2.2 Production of Natural Fibre Composites (70)11.2.3 Natural Fibre Composites in comparison tobiofuels (70)11.2.4 Wood-Plastic Composites (72)11.3 Conclusion (73)12 References (74)Order the full reportThe full report can beordered for 1,000 €plus VAT atwww.bio-based.eu/marketsFigures include:Figure I: Application fields of WPC in Europe in2012 (Total production 260.000 tonnes, allproduction processes) (nova 2014) (7)Figure II: Use of wood and natural fibres forcomposites in the European automotiveindustry in 2012, including cotton andwood (total volume: 80,000 tonnes).“Others” are mainly jute, coir, sisaland abaca (nova 2014) (7)Figure 1.1: Description of biocomposites(nova 2014) (10)Figure 2.1: European plastics demand(PlasticsEurope 2013) (12)Figure 2.2: European plastics demand by segmentand resin type in 2012(PlasticsEurope 2013) (12)Figure 2.3: Prices of common plastics (nova 2014,based on Kunststoff Information 2013) (12)Figure 4.1: WPC production processes in Europe in2012 (nova 2014) (20)Figure 4.2: Polymer usage in European WPC decking(extrusion only) in 2012 (nova 2014) (20)Figure 4.3: One and two-step WPC extrusionprocess overview (Daniel & Kahr 2011) (21)Figure 4.4: Components of a typical WPC extrusionline (Weber 2013) (22)Figure 5.1: Application fields of WPC produced inEurope 2012 (nova 2014) (26)Figure 5.2: Application fields of extruded WPCproduced in Europe, 2012 (nova 2014) (26)Figure 5.3: Main countries of European WPC production of decking, fencing and other constructionapplications (nova 2014) (26)Figure 5.9: Polymer usage in European WPC decking(extrusion only) (nova 2014) (29)Figure 5.10: Price ranges per terrace surface from asurvey of German decking distributionchannels in 2013 (nova 2014) (30)Figure 5.11: Price ranges of decking from a surveyof German decking distribution channelsin 2013 (Asta Eder Composites Consulting2009 and 2011, nova 2014) (30)Figure 5.12: Comparison of different profile geometriesand production costs (Weber 2013) ........31Figure 6.1: Development of North American multiand single family housings starts(Van Eaton 2013) (32)Figure 6.2: Global production of WPC in 2010 and2012, and forecast for 2015 (nova 2014) .33 Figure 6.3: WPC-MDF boards in India(Hardy Smith 2012) (34)Figure 6.4: Global number of WPC-producingcompanies in 2012 (n=671)(nova 2014) (34)Figure 6.6: Main application fields of Chinese WPCproducts in 2012(n=422 producers) (Song 2013) (35)Figure 6.7: Development of the sales volume of theChinese WPC industry (Song 2013) (35)Figure 6.8: Production of WPC solid decking board with capstock layer for export to North Americain Ningbo Helong New Material Ltd(Picture: Eder 2012) (36)Figure 6.9: WPC production in Russia by type ofproduct in 2013 (Inventra 2013) (36)Figure 6.10: Overall and WPC decking production inRussia in 2012 and 2013(in tonnes) (Inventra 2013) (37)Figure 6.11: Consumption of polymers for the production of WPC in 2013 – total 5,500 tonnes(Inventra 2013) (37)Figure 7.1: Value added of WPC and NFC – extrusionand injection moulding (Eder 2013) (38)Figure 7.4: Mechanical properties of different injection-moulded materials I – impact and stiffness(nova 2014) (41)Figure 7.5: Mechanical properties of different injection-moulded materials II – impact and tensilestrength (nova 2014) (41)Figure 7.6: Mechanical properties of different injection-moulded materials III – stiffness and tensilestrength (nova 2014) (41)Figure 7.7: Mechanical properties of different injection-moulded materials IV – shrinkage andtemperature resistance (nova 2014) (42)Figure 8.1: World fibre consumption 1980 – 2012(The Fiber Year 2013) (46)Figure 8.2: Market shares in 2012 (The Fiber Year2013) (46)。
references of the european and national legislation
EUROPEAN COMMISSIONHEALTH & CONSUMER PROTECTION DIRECTORATE-GENERALDirectorate E – Safety of the food chainE3 – Chemicals, contaminants and pesticidesFile:INT/REF_LEG+Compend (2006.02.27) REFERENCES OF THE EUROPEAN ANDNATIONAL LEGISLATIONS(Version updated 27 February 2006)IntroductionThe references of the EU Directives and Regulations as well as of the national legislation are mentioned hereinafter. As regards the EU Directives, you can find, in general, the references and the texts on the “EUR-LEX” website http://europa.eu.int/eur-lex/lex/en/index.htm. On this website you can also find information on where and how you can purchase the Official Journal of the European Union.EUROPEAN DIRECTIVES AND REGULATIONS[1] 76/893/EECCouncil Directive of 23 November 1976 on the approximation of the laws of the Member States relating to materials and articles intended to come into contact with foodstuffs.O.J. n° L340, of 09.12.1976(Old framework directive, repealed by Directive 89/109/EEC [11])[2] 78/142/EECCouncil Directive of 30 January 1978 on the approximation of the laws of the Member States relating to materials and articles which contain vinyl chloride monomer and are intended to come into contact with foodstuffs.O.J. n° L44, of 15.02.1978, p.15(Plastics: limits on vinyl chloride monomer (VCM))[3] 80/590/EECCommission Directive of 9 June 1980 determining the symbol that may accompany materialsand articles intended to come into contact with foodstuffs.O.J. n° L151, of 19.06.1980, p.21(Symbol for materials and articles, repealed by Framework Regulation (EC) No 1935/2004 [34])official control of the vinyl chloride monomer level in materials and articles which are intended to come into contact with foodstuffs.O.J. n° L213, of 16.08.1980, p.42(Plastics: Determination of VCM in finished products)[5] 81/432/EECCommission Directive of 29 April 1981 laying down the Community method of analysis for the official control of vinyl chloride released by materials and articles into foodstuffs.O.J. n° L167, of 24.06.1981, p.6(Plastics: Determination of VCM in foods)[6] 82/711/EECCouncil Directive of 18 October 1982 laying down the basic rules necessary for testing migration of the constituents of plastic materials and articles intended to come into contact with foodstuffs.O.J. n° L297, of 23.10.1982, p.26(Plastics: Basic rules for testing migration)[7] 83/229/EECCouncil Directive of 25 April 1983 on the approximation of the laws of the Member States relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffs.O.J. n° L123, of 11.05.1983, p.31(Regenerated Cellulose, repealed by Directive 93/10/EEC[18])[8] 84/500/EECCouncil Directive of 15 October 1984 on the approximation of the laws of the Member States relating to ceramic articles intended to come into contact with foodstuffs.O.J. n° L277, of 20.10.1984, p.12(Ceramics)[9] 85/572/EECCouncil Directive of 19 December 1985 laying down the list of simulants to be used for testing migration of constituents of plastic materials and articles intended to come into contact with foodstuffs.O.J. n° L372, of 31.12.1985, p.14(Plastics: list of simulants for testing migration)approximation of the laws of the Member States relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffs.O.J. n° L228, of 14.08.1986, p.32(Regenerated Cellulose: 1st Amendment, repealed byDirective 93/10/EEC [18])[11] 89/109/EECCouncil Directive of 21 December 1988 on the approximation of the laws of the Member States relating to materials and articles intended to come into contact with foodstuffs.O.J. n° L40, of 11.02.1989, p.38Corrigendum O.J. n° L347 of 28.11.89, p.37(Framework Directive repealed by Framework Regulation 1935/2004 [34])[12] 90/128/EECCommission Directive of 23 February 1990 relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L75, of 21.03.1990, p.19(Plastics: general rules, repealed by Directive 2002/72/EC [28])Corrigendum O.J. n° L349 of 13.12.1990, p.26[13] 92/15/EECCommission Directive of 11 March 1992, amending Council Directive 83/229/EEC on the approximation of the laws of the Member States relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffs.O.J. n° L102, of 16.04.1992, p.44(Cellulose regenerated: 2nd Amendment, repealed by Directive 93/10/EEC [18])[14] 92/39/EECCommission Directive of 14 May 1992, amending Directive 90/128/EEC concerning plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L168, of 23.06.1992, p.21(Plastics, Ist amendment, repealed by Directive 2002/72/EC [28])[15] 93/9/EECCommission Directive of 15 March 1993 amending for the second time Directive 90/128/EEC relating to plastics materials and articles intended to come in contact with foodstuffsO.J. n° L90, of 14.4.93, p.26(Plastics, 2nd Amendment, repealed by Directive 2002/72/EC [28])[16] 93/11/EECCommission Directive of 15 March 1993 concerning the release of the N-nitrosamines and N-nitrosatable substances from rubber teats and soothersO.J. n° L93, of 17.4.93, p.37(Rubber: Limits for nitrosamines)down the basic rules necessary for testing migration of the constituents of plastics materials and articles intended to come into contact with foodstuffsO.J. n° L90, of 14.4.93, p.22(Plastics: Basic rules for testing migration - 1st amendment)[18] 93/10/EECCommission Directive of 15 March 1993 relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffsO.J. n° L93, of 17.4.93, p.27(Regenerated Cellulose: Codification of 83/229/EEC)[19] 93/111/EECCommission Directive of 10 December 1993, amending Directive 93/10/EEC relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffs.O.J. n° L310 of 14.12.1993, p.41(Regenerated Cellulose: 1. Amendment)[20] 95/3/ECCommission Directive of 14 February 1995, amending Directive 90/128/EEC relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L41 of 23 February 1995, p.44(Plastics: 3rd amendment, repealed by Directive 2002/72/EC [28])[21] 96/11/ECCommission Directive of 5 March 1996, amending Directive 90/128/EEC relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L61 of 12 March 1996, p.26(Plastics: 4th amendment, repealed by Directive 2002/72/EC [28])[22] 97/48/ECCommission Directive of 29 July 1997 amending for second time Council Directive 82/711/EEC laying down the basic rules necessary for testing migration of the constituents of plastics materials and articles intended to come into contact with foodstuffsO.J. n° L222, of 12.8.97, p 10(Plastics: Basic rules for testing migration - 2nd amendment)[23] 99/91/ECCommission Directive of 23 November 1999, amending Directive 90/128/EEC relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L310 of 4 December 1999, p.41(Plastics: 5th amendment, repealed by Directive 2002/72/EC [28])[24] 2001/61/ECCommission Directive of 8 August 2001 on the use of certain epoxy derivatives in materials and articles intended to come into contact with foodstuffs.O.J. n° L215 of 9 August 2001, p.26(Badge/Bfdge/Noge, repealed by Directive 2002/16/EC [26])[25] 2001/62/ECCommission Directive of 9 August 2001 amending Directive 90/128/EEC relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L221 of 17 August 2001, p.18(Plastics: 6th amendment, repealed by Directive 2002/72/EC [28])[26] 2002/16/ECCommission Directive of 20 February 2002 on the use of certain epoxy derivatives in materials and articles intended to come into contact with foodstuffs.O.J. n° L51 of 22.02.2002, p.27(BADGE/BFDGE/NOGE, repealed by Regulation (EC) 1895/2005)[27] 2002/17/ECCommission Directive of 21 February 2002 amending Directive 90/128/EEC relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L58 of 28.02.2002, p.19(Plastics : 7th amendment, repealed by Directive 2002/72/EC[28])[28] 2002/72/ECCommission Directive of 6 August 2002 relating to plastics materials and articles intended to come into contact with foodstuffs.O.J. n° L220 of 15.08.2002, p.18(Plastics : Codification of 90/128/EEC + 7 amendments)[29] Corrigendum to 2002/72/ECCorrigendum to Commission Directive 2002/72/EC of 6 August 2002 relating to plastic materials and articles intended to come into contact with foodstuffs.O.J. n° L39 of 13.02.2003, p.1(Plastics : Codification of 90/128/EEC + 7 amendments)[30] 2004/1/ECCommission Directive of 6 January 2004 amending Directive 2002/72/EC as regards the suspension of the use of azodicarbonamide as blowing agentO.J. n° L7 of 13.01.2004, p.45(Plastics : first amendment to Directive 2002/72/EC)[31] 2004/13/ECCommission Directive of 29 January 2004 amending Directive 2002/16/EC on the use of certain epoxy derivatives in materials and articles intended to come into contact with foodstuffsO.J. n° L27 of 30.01.2004, p.46(BADGE, BFDGE, NOGE : first amendment to Directive 2002/16/EC; repealed by Regulation (EC) No 1895/2005 )[32] 2004/14/ECCommission Directive of 29 January 2004 amending Directive 93/10/EEC relating to materials and articles made of regenerated cellulose film intended to come into contact with foodstuffsO.J. n° L27 of 30.01.2004, p.48(Regenerated Cellulose : 2nd amendment to Directive 93/10/EEC)[33] 2004/19/ECCommission Directive of 01 March 2004 amending Directive 2002/72/EC 2002 relating to plastic materials and articles intended to come into contact with foodstuffsO.J. n° L71 of 10.03.2004, p.8(Plastics : 2nd amendment to Directive 2002/72/EC)[34] 1935/2004/ECRegulation of the European Parliament and of the Council of 27 October 2004 on materialsand articles intended to come into contact with food and repealing Directives 80/590/EEC and89/109/EECO.J. n° L338 of 13.11.2004, p.4(Framework Regulation)[35] 2005/31/ECCommission Directive of 29 April 2005 amending Council Directive 84/500/EEC as regards a declaration of compliance and performance criteria of the analytical method for ceramic articles intended to come into contact with foodstuffsO.J. n° L110 of 30.04.2005, p.36(Ceramics - amendment)[36] 1895/2005/ECCommission Regulation of 18 November 2005 on the restriction of use of certain epoxy derivatives in materials and articles intended to come into contact with foodO.J. n° L302 of 19.11.2005, p.28(BADGE, BFDGE, NOGE)[37] 2005/79/ECCommission Directive of 18 November 2005 amending Directive 2002/72/EC relating to plastic materials and articles intended to come into contact with food.O.J. n° L302 of 19.11.2005, p.35(Plastics: 3rd amendment to Directive 2002/72/EC)OTHER EU DIRECTIVES AND REGULATIONS RELATED TO FOOD CONTACT MATERIALS[1] 85/591/EECCouncil Directive of 20 December 1985 concerning the introduction of Community methods of sampling and analysis for the monitoring of foodstuffs intended for human consumption O.J. n° L372 of 31.12.1985, p 50(Foodstuffs and Food Contact Materials: Control, repealed by Regulation (EC) 882/2004[4])) [2] 89/397/EECCouncil Directive of 14 June 1989 on the official control of foodstuffsO.J. n° L186, of 30.6.89, p 23(Foodstuffs and Food Contact Materials: Control, repealed by Regulation (EC) 882/2004[4]) [3] 93/99/EECCouncil Directive of 29 October 1993 on the subject of additional measures concerning the official control of foodstuffsO.J. n° L290 of 24.11.93, p 14(Foodstuffs and Food Contact Materials: Control, repealed by Regulation (EC) 882/2004[4]) [4] (EC) No 882/2004Regulation of the European Parliament and of the Council of 29 April 2004 on official controls performed to ensure the verification of compliance with feed and food law, animal health and animal welfare rulesO.J. n° L165 of 30.04.04, p 1(Foodstuffs and Food Contact Materials: Control)[5] (EC) No 242/2004Commission Regulation of 12 February 2004 amending Regulation (EC) No 466/2001 as regards inorganic tin in foodsO.J. n° L42 of 13.02.04, p 3(Tin in canned Foodstuffs)[6] 2004/16/ECCommission Directive of 12 February 2004 laying down the sampling methods and the methods of analysis for the official control of the levels of tin in canned foodsO.J. n° L42 of 13.02.04, p 3(Tin in canned Foodstuffs: Control)REFERENCES OF NATIONAL LEGISLATIONSee the document below. For further information on national legislation, you can contact National Authorities (see addresses in the document “EU and National Authorities”)AUSTRIASUMMARYAll EC Directives implemented as listed below.Additional national provisions.Legislation published in the Bundesgesetzblatt für die Republik Österreich (BGBl.)http://bgbl.wzo.at/web site: http://www.ris.bka.gv.atLegislation is made under powers of the Lebensmittelgesetz [Food Act] 1975, BGBl. Nr. 86/1975, the Bundesgesetz gegen den unlauteren Wettbewerb 1984, BGBl. Nr. 448/2984, Chemikaliengesetz, BGBl. Nr. 53/1997 Teil I, and the Abfallwirtschaftsgesetz, BGBl. Nr. 325/1990.Sales Agents :Print Media Austria AG, Verlag ÖsterreichPostfach G 7 (Tenschertstraße 7) A 1239 WienTel. (+43 1) 797 89 DW 294 Fax (+43 1) 797 89 DW 442e-mail: bgbl@verlagoesterreich.at Buchhandlung Verlag ÖsterreichWollzeile 16A 1010 WienTel. (+43 1) 512 48 85Manz´sche Verlags-u. UniversitätsbuchhandlungKohlmarkt 16A 1010 WienTel. (+43 1) 531 61IMPLEMENTATION OF EC DIRECTIVESALL FOOD CONTACT MATERIALS89/109/EEC (framework) Lebensmittelgesetz 86/1975 i.d.F.BGBl. Nr. 63/1998 Teil I ausgegeben am 30/04/1998, zuletzt geändert durch BGBl. I Nr.69/2003Verordnung des Bundesministers für wirtschaftliche Angelegenheiten über dieKennzeichung von Gebrauchsgegenständen, die für die Verwendung bei Lebensmittelnbestimmt sindBGBl. Nr. 217/1995, ausgegeben am 28/03/199580/590/EEC (symbol) Verordnung des Bundesministers für wirtschaftliche Angelegenheiten über dieKennzeichung von Gebrauchsgegenständen, die für die Verwendung bei Lebensmittelnbestimmt sindBGBl. Nr. 217/1995, ausgegeben am 28/03/1995PLASTICS Monomers & additives2002/72/ECCodification of 90/128/EEC + 7 Amendments2004/1/EC2004/19/EC Lebensmittelgesetz 86/1975 i.d.F.BGBl. Nr. 63/1998 Teil I ausgegeben am 30/04/1998, zuletzt geändert durch BGBl. I Nr.69/2003Kunststoff—Verordnung (KVO)Full title - Verordnung der Bundesministerin für Gesundheit und Frauen über Gebrauchsgegenstände aus Kunststoff, die für die Verwendung bei Lebensmitteln und Verzehrprodukten bestimmt sindBGBl. II Nr. 476/2003 ausgegeben am 14/10/2003Änderung der Kunststoffverordnung 2003BGBl. II Nr. 242/2005 ausgegeben am 01.08.2005PLASTICS Testing82/711/EEC (basic rules) 85/572/EEC (simulants) KVOBGBl. II Nr. 476/2003 ausgegeben am 14/10/200393/8/EEC (1st amend. 82/711/EEC) KVOBGBl. II Nr. 476/2003 ausgegeben am 14/10/2003 97/48/EC (2nd. amend. 82/711/EEC) KVOBGBl. II Nr. 476/2003 ausgegeben am 14/10/200311 PLASTICS Vinyl chloride monomer78/142/EEC 80/766/EEC 81/432/EEC KVOBGBl. II Nr. 476/2003 ausgegeben am 14/10/2003REGENERATED CELLULOSE FILM93/10/EEC93/111/EEC (1st amend. 93/10/EEC) 2004/14/EC Verordnung des Bundesministers für wirtschaftliche Angelegenheiten über die Kennzeichung von Gebrauchsgegenständen, die für die Verwendung bei Lebensmitteln bestimmt sindBGBl. Nr. 217/1995, ausgegeben am 28/03/1995Zellglasfolien-VerordnungFull title - Verordnung des Bundesministers für Gesundheit, Sport und Konsumentenschutz über Gebrauchgegenstände aus ZellglasfolieBGBl. Nr. 128/1994, ausgegeben am 22/02/1994Änderung der Zellglasfolien-VerordnungBGBl. II Nr. 298/2005 ausgegeben am 09/09/2005CERAMICS84/500/EEC Keramik-VerordnungFull title - Verordnung des Bundesministers für Gesundheit, Sport und Konsumentenschutzüber Gebrauchsgegenstände aus Keramik und Gebrauchsgegenstände mit einem Überzugaus EmailBGBl. Nr. 893/1993 ausgegeben am 23/12/1993BADGE, BFDGE, NOGE2002/16/EC 2004/13/EC Epoxyderivate-VerordnungFull title - Verordnung des Bundesministers für soziale Sicherheit und Generationen über die Verwendung bestimmter Epoxyderivate in Gebrauchsgegenständen, die dazu bestimmt sind, mit Lebensmitteln und Verzehrprodukten in Berührung zu kommenBGBl.II Nr. 161/2003 ausgegeben am 21/02/2003Änderung der Epoxyderivate-VerordnungBGBl. II Nr.36/2005 ausgegeben am 08.02.2005RUBBER93/11/EEC (Limits for Nitrosamines) Nitrosamin-VerordnungFull title – Verordnung des Bundesministers für Gesundheit und Konsumentenschutz überdie Freisetzung von N-Nitrosaminen und N-nitrosierbaren Stoffen aus Flaschen- undBeruhigungssaugern aus Elastomeren oder GummiBGBl. Nr. 104/1995 ausgegeben am 10/02/1995ADDITIONAL (NON-EC) NATIONAL PROVISIONSGeschirrverordnungBGBl. 258/1960 ausgegeben am 23/11/1960Verordnung über den Verkehr mit Essigsäure zu GenußzweckenBGBl. 148/1959 ausgegeben am 29/06/1959Verordnung über die Kennzeichnung von Verpackungen aus KunststoffenBGBl. 137/1992 ausgegeben am 13/03/1992CadmiumverordnungBGBl. 855/1993 ausgegeben am 16.12.1993BELGIUMSUMMARYAll EC Directives implemented.Additional national provisions.Belgian legislation on materials and articles which come into contact with foodstuff is published in the Belgian Official newspaper, "Le Moniteur Belge", and on the internet. The web site address is : http://www.moniteur.beIMPLEMENTATION OF EC DIRECTIVESALL FOOD CONTACT MATERIALSRÈGLEMENT (CE) No 1935/2004 DU PARLEMENT EUROPÉEN ET DU CONSEIL du 27 octobre 2004 concernant les matériaux et objets destinés à entrer en contact avec des denrées alimentaires et abrogeant les directives 80/590/CEE et 89/109/CEE PLASTICS Monomers & additives2002/72/EC (Consolidation) 2004/1/EC2004/19/EC Arrêté royal du 3 juillet 2005 relatif aux matériaux et aux objets en matière plastique destinés à entrer en contact avec les denrées alimentairesPLASTICS Testing82/711/EEC (basic rules) Arrêté royal du 11 mai 1992 concernant les matériaux et objets destinés à entrer en contactavec les denrées alimentaires85/572/EEC (simulants) Arrêté royal du 11 mai 1992 concernant les matériaux et objets destinés à entrer en contactavec les denrées alimentaires93/8/EEC (1st amend. 82/711/EEC) Arrêté royal du 9 juillet 1993 modifiant l'arrêté royal du 11 mai 199297/48/EEC (2nd amend 82/711/EEC) Arrêté royal du 20 octobre 1998 modifiant l'arrêté royal du 11 mai 1992PLASTIC Vinyl chloride monomer78/142/EEC Arrêté royal du 3 juillet 2005 relatif aux matériaux et aux objets en matière plastique destinésà entrer en contact avec les denrées alimentaires80/766/EEC Arrêté royal du 11 mars 1983 fixant les méthodes d'analyses pour la détermination duchlorure de vinyle dans les matériaux et objets destinés à entrer en contact avec les denréesalimentaires et du chlorure de vinyle cédé par les matéraiux et objets aux denréesalimentaires.81/432/EEC Arrêté royal du 11 mars 1983 fixant les méthodes d'analyses pour la détermination duchlorure de vinyle dans les matériaux et objets destinés à entrer en contact avec les denréesalimentaires et du chlorure de vinyle cédé par les matéraiux et objets aux denréesalimentaires.REGENERATED CELLULOSE FILM93/10/EEC 93/111/EC 2004/14/EC Arrêté royal du 23 novembre 2004 relatif aux matériaux et aux objets en pellicule de cellulose régénérée, destinés à entrer en contact avec les denrées alimentairesCERAMIC84/500/EEC Arrêté royal du 11 mai 1992 concernant les matériaux et objets destinés à entrer en contactavec les denrées alimentaires.BADGE, BFDGE, NOGE2002/16/EC Arrêté royal du 20 septembre 2002 concernant l’utilisation de certains dérivés époxydiquesdans des matériaux et des objets destinés à entrer en contact avec des denrées alimentaires. 2004/13/EC Arrêté royal 22 septembre 2004 modifiant l’arrêté royal du 20 septembre 2002 concernantl’utilisation de certains dérivés époxydiques dans des matériaux et des objets destinés à entreren contact avec des denrées alimentairesADDITIONAL (NON-EC) NATIONAL REGULATIONS AND RECOMMENDATIONSRésolution AP (97) 1 du Conseil de l'Europe concernant les résines échangeuses d'ions destinées à entrer en contact avec des denrées alimentairesRésolution AP (96) 5 du Conseil de l'Europe concernant les vernis destinés à entrer en contact avec des denrées alimentairesRésolution AP (99) 3 du Conseil de l'Europe concernant les silicones destinés à entrer en contact avec des denrées alimentaires Ces dispositions sont en cours d'adaptation au niveau belgeCYPRUSSUMMARYThe Regulation 1935/2004/EC and all EC Directives (except 2004/1/EC, 2004/14/EC, 2004/19/EC and 2005/31/EC) are implemented and incorporated in the following Cyprus Regulations:The Materials and Articles for Contact with Foodstuffs Regulations of 2004:published in Cyprus Official Gazette, E.E.Παρ. ΙΙΙ(I), Αρ.3850, 30.4.2004,Κ.∆.Π.450/2004;The Materials and Articles for Contact with Foodstuffs Regulations of 2005 amending the basic Regulations of 2004: published in Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3988, 6.5.2005, Κ.∆.Π. 225/2005.These regulations have been enacted and edited under the Food (Control and Safe) Law, published in Cyprus Official Gazette, Ε.Ε.Παρ.Ι,Ν54(I)96 - Ν27(Ι)2005. (Κ.∆.Π. = Regulatory Administrative Act, Αρ.= Νο , E.E.Παρ. =Official Gazette Appendix ) The State General Laboratory is the official laboratory for the implementation of the above Regulations.Legislations are made under the powers of the Council of the Ministry.Legislations are published in the Cyprus Official Gazette (ΕπίσηµηΕφηµερίδατηςΚυπριακής∆ηµοκρατίας) after its approval by the Parliament.Sales Agent:Government printing office of the Republic of Cyprus1445 NicosiaTel. 00357-22 405801-802Fax. 00357-22 303175ALL FOOD CONTACT MATERIALS1935/2004/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3988, 6.5.2005, Κ.∆.Π. 225/2005(Κ.∆.Π. = Regulatory Administrative Act, Αρ.= Νο , E.E.Παρ. =Official Gazette Appendix )IMPLEMENTATION OF EC DIRECTIVESPLASTICS Monomers & additives2002/72//EC 2004/19/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 Under publicationPLASTICS Testing82/711/EEC (basic rules) 85/572/EEC (simulants) Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/200493/8/EEC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I),Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 97/48/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I),Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 PLASTICS Vinyl chloride monomer78/142/EEC 80/766/EEC 81/432/EEC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004REGENERATED CELLULOSE FILM93/10/EEC 93/111/EEC 2004/14/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 Under publicationCERAMICS84/500/EEC 2005/31/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 The procedure not started yetRUBBERS: N-NITROSAMINES93/11/EEC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I),Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 USE OF AZODICARBONAMIDE AS BLOWING AGENT2004/1/EC UnderpublicationBADGE /BFDGE/NOGE BADGE /BFDGE/NOGE2002/16/EC 2004/13/EC Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), Αρ. 3850, 30.4.2004, Κ.∆.Π. 450/2004 Cyprus Official Gazette, E.E.Παρ. ΙΙΙ (I), & Αρ. 3988, 6.5.2005, Κ.∆.Π. 225/2005CZECH REPUBLICSUMMARY•All EC Directives implemented•Additional national provisions•Legislation published in the Collection of Law Czech Republic. Web site : http://mvcr.cz•Legislation is made under powers of the Ministry of Health in the Act No. 258/2000 Sb. o ochraně veřejného zdraví (relating to public health protection)•Sales Agents: Ministerstvo vnitra České republikyNad Štolou 936/3,170 34 Praha 7 – HolešoviceIMPLEMENTATION OF EC DIRECTIVESALL FOOD CONTACT MATERIALSRegulation (EC)1935/2004 Zákon 258/2000 Sb., o ochraně veřejného zdraví a o změněněkterých souvisejících zákonů v platném znění(zákon ze dne 14.července 2000, vydaný ve Sbírce zákonůČeskérepubliky, částce 74, dne 11.8.2000)Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy ve znění 2.novely z roku2005, kterou se mění vyhláška č.38/2001PLASTICS Monomers & additives2002/72/EC Vyhláškač.186/2003, kterou se mění vyhláška č.38/2001 ohygienických požadavcích na výrobky určené pro styks potravinami a pokrmy(vyhláška ze dne 9.června 2003, vydaná ve Sbírce zákonůČeskérepubliky, částce 65, dne 24.června 2003)2004/1/EC Vyhláškač.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy ve znění 2.novely z roku2005, kterou se mění vyhláška č.38/20012004/19/EC Vyhláškač.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy ve znění 2.novely z roku2005, kterou se mění vyhláška č.38/2001PLASTICS Testing82/711/EEC (basic rules) 85/572/EEC (simulants) Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy(vyhláška ze dne 19.ledna 2001, vydaná ve Sbírce zákonůČeské republiky, částce 13, dne 1.2.2001)93/8/EEC (1st amend. 82/711/EEC) Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy(vyhláška ze dne 19.ledna 2001, vydaná ve Sbírce zákonůČeskérepubliky, částce 13, dne 1.2.2001)97/48/EC (2nd. amend. 82/711/EEC) Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy(vyhláška ze dne 19.ledna 2001, vydaná ve Sbírce zákonůČeskérepubliky, částce 13, dne 1.2.2001)PLASTICS Vinyl chloride monomer78/142/EEC 80/766/EEC 81/432/EEC Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy(vyhláška ze dne 19.ledna 2001, vydaná ve Sbírce zákonůČeské republiky, částce 13, dne 1.2.2001)REGENERATED CELLULOSE FILM93/10/EEC93/111/EEC (1st amend. 93/10/EEC) 2004/14/EC Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy(vyhláška ze dne 19.ledna 2001, vydaná ve Sbírce zákonůČeské republiky, částce 13, dne 1.2.2001)Vyhláška č.38/2001 o hygienických požadavcích na výrobkyurčené pro styk s potravinami a pokrmy ve znění 2.novely z roku 2005, kterou se mění vyhláška č.38/2001.。
Single defect centres in diamond-A review
phys. stat. sol. (a) 203, No. 13, 3207–3225 (2006) / DOI 10.1002/pssa.200671403© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Review ArticleSingle defect centres in diamond: A reviewF. Jelezko and J. Wrachtrup *3. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, GermanyReceived 9 February 2006, revised 28 July 2006, accepted 9 August 2006Published online 11 October 2006PACS 03.67.Pp, 71.55.–r, 76.30.Mi, 76.70.–rThe nitrogen vacancy and some nickel related defects in diamond can be observed as single quantum sys-tems in diamond by their fluorescence. The fabrication of single colour centres occurs via generation of vacancies or via controlled nitrogen implantation in the case of the nitrogen vacancy (NV) centre. The NV centre shows an electron paramagnetic ground and optically excited state. As a result electron and nuclear magnetic resonance can be carried out on single defects. Due to the localized nature of the electron spin wavefunction hyperfine coupling to nuclei more than one lattice constant away from the defect as domi-nated by dipolar interaction. As a consequence the coupling to close nuclei leads to a splitting in the spec-trum which allows for optically detected electron nuclear double resonance. The contribution discusses the physics of the NV and other defect centre from the perspective of single defect centre spectroscopy.© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim1 IntroductionThe ever increasing demand in computational power and data transmission rates has inspired researchers to investigate fundamentally new ways to process and communicate information.Among others, physicists explored the usefulness of “non-classical”, i.e. quantum mechanical systems in the world of information processing. Spectacular achievements like Shors discovery of the quantum factoring algorithm [1] or the development of quantum secure data communication gave birth to the field of quantum information processing (QIP) [2]. After an initial period where the physical nature of infor-mation was explored [3] and how information processing can be carried out by unitary transformation in quantum mechanics, researchers looked out for systems which might be of use as hardware in QIP. From the very beginning it became clear that the restrictions on the hardware of choice are severe, in particular for solid state systems. Hence in the recent past scientists working in the development of nanostructured materials and quantum physics have cooperated on different solid-state systems to define quantum me-chanical two-level system, make them robust against decoherence and addressable as individual units. While the feasibility of QIP remains to be shown, this endeavour will deepen our understanding of quan-tum mechanics and also marks a new area in material science which now also has reached diamonds as a potential host material. The usefulness of diamond is based on two properties. First defects in diamond are often characterized by low electron phonon coupling, mostly due to the low density of phonon states i.e. high Debye temperature of the material [4]. Secondly, colour centres in diamond are usually found to be very stable, even under ambient conditions. This makes them unique among all optically active solid-state systems.* Corresponding author: e-mail: wrachtrup@physik.uni-stuttgart.de3208 F. Jelezko and J. Wrachtrup: Single defect centres in diamond: A review© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The main goal of QIP is the flexible generation of quantum states from individual two-level systems (qubits). The state of the individual qubits should be changed coherently and the interaction strength among them should be controllable. At the same time, those systems which are discussed for data com-munication must be optically active which means, that they should show a high oscillator strength for an electric dipole transition between their ground and some optically excited state. Individual ions or ion strings have been applied with great success. Here, currently up to eight ions in a string have been cooled to their ground state, addressed and manipulated individually [5]. Owing to careful construction of the ion trap, decoherence is reduced to a minimum [6]. Landmark experiments, like teleportation of quantum states among ions [7, 8] and first quantum algorithms have been shown in these systems [9, 10].In solid state physics different types of hardware are discussed for QIP. Because dephasing is fast in most situations in solids only specific systems allow for controlled generation of a quantum state with preservation of phase coherence for a sufficient time. Currently three systems are under discussion. Su-perconducting systems are either realized as flux or charge quantized individual units [11]. Their strength lies in the long coherence times and meanwhile well established control of quantum states. Main pro-gresses have been achieved with quantum dots as individual quantum systems. Initially the electronic ground as well as excited states (exciton ground state) have been used as definition of qubits [12]. Mean-while the spin of individual electrons either in a single quantum dot or coupled GaAs quantum dots has been subject to control experiments [13–15]. Because of the presence of paramagnetic nuclear spins, the electron spin is subject to decoherence or a static inhomogeneous frequency distribution. Hence, a further direction of research are Si or SiGe quantum dots where practically no paramagnetic nuclear spins play a significant role. The third system under investigation are phosphorus impurities in silicon [16]. Phospho-rus implanted in Si is an electron paramagnetic impurity with a nuclear spin I = 1/2. The coherence times are known to be long at low temperature. The electron or nuclear spins form a well controllable two-level system. Addressing of individual spins is planned via magnetic field gradients. Major obstacles with respect to nanostructuring of the system have been overcome, while the readout of single spins based on spin-to-charge conversion with consecutive detection of charge state has not been successful yet. 2 Colour centres in diamondThere are more then 100 luminescent defects in diamond. A significant fraction has been analysed in detail such that their charge and spin state is known under equilibrium conditions [17]. For this review nitrogen related defects are of particular importance. They are most abundant in diamond since nitrogen is a prominent impurity in the material. Nitrogen is a defect which either exists as a single substitutional impurity or in aggregated form. The single substitutional nitrogen has an infrared local mode of vibration Fig. 1 (online colour at: ) Schematic represen-tation of the nitrogen vacancy (NV) centre structure.phys. stat. sol. (a) 203, No. 13 (2006) 3209 © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim65070075080050010001500T =300KT =1.8K F l u o r e s c e n c e I n t e n s i t y ,C t s Wavelength,nm ZPL 637.2nmat 1344 cm –1. The centre is at a C 3v symmetry site. It is a deep electron donor, probably 1.7 eV below the conduction band edge. There is an EPR signal associated with this defect, called P1, which identifies it to be an electron paramagnetic system with S = 1/2 ground state [17]. Nitrogen aggregates are, most com-monly, pairs of neighbouring substitutional atoms, the A aggregates, and groups of four around a va-cancy, the B aggregate. All three forms of nitrogen impurities have distinct infrared spectra.Another defect often found in nitrogen rich type Ib diamond samples after irradiation damage is the nitrogen vacancy defect centre, see Fig. 1. This defect gives rise to a strong absorption at 1.945 eV (637 nm) [18]. At low temperature the absorption is marked by a narrow optical resonance line (zero phonon line) followed by prominent vibronic side bands, see Fig. 2. Electron spin resonance measure-ment have indicated that the defect has an electron paramagnetic ground state with electron spin angular momentum S = 1 [19]. The zero field splitting parameters were found to be D = 2.88 GHz and E = 0 indicating a C 3v symmetry of the electron spin wavefunction. From measurements of the hyperfine cou-pling constant to the nitrogen nuclear spin and carbon spins in the first coordination shell it was con-cluded that roughly 70% of the unpaired electron spin density is found at the three nearest neighbour carbon atoms, whereas the spin density at the nitrogen is only 2%. Obviously the electrons spend most of their time at the three carbons next to the vacancy. To explain the triplet ground state mostly a six elec-tron model is invoked which requires the defect to be negatively charged i.e. to be NV – [20]. Hole burn-ing experiments and the high radiative recombination rate (lifetime roughly 11 ns [21], quantum yield 0.7) indicate that the optically excited state is also a spin triplet. The width of the spectral holes burned into the inhomogeneous absorption profile were found to be on the order of 50 MHz [22, 23]. Detailed investigation of the excited state dephasing and hole burning have caused speculations to as whether the excited state is subject to a J an–Teller splitting [24, 25]. From group theoretical arguments it is con-cluded that the ground state is 3A and the excited state is of 3E symmetry. In the C 3v group this state thus comprises two degenerate substrates 3E x,y with an orthogonal polarization of the optical transition. Photon echo experiments have been interpreted in terms of a Jan Teller splitting of 40 cm –1 among these two states with fast relaxation among them [24]. However, no further experimental evidence is found to sup-port this conclusion. Hole burning experiments showed two mechanisms for spectral hole burning: a permanent one and a transient mechanism with a time scale on the order of ms [23]. This is either inter-preted as a spin relaxation mechanism in the ground state or a metastable state in the optical excitation-emission cycle. Indeed it proved difficult to find evidence for this metastable state and also number and energetic position relative to the triplet ground and excited state are still subject of debate. Meanwhile it seems to be clear that at least one singlet state is placed between the two triplet states. As a working hypothesis it should be assumed throughout this article that the optical excitation emission cycle is de-scribed by three electronic levels.Fig. 2 Fluorescence emission spectra of single NVcentres at room temperature and LHe temperatures.Excitation wavelength was 514 nm.3210 F. Jelezko and J. Wrachtrup: Single defect centres in diamond: A review© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 3 Optical excitation and spin polarizationGiven the fact that the NV centre has an electron spin triplet ground state with an optically allowed tran-sition to a 3E spin triplet state one might wonder about the influence of optical excitation on the electron spin properties of the defect. Indeed in initial experiments no electron spin resonance (EPR) signal of the defect was detected except when subject to irradiation in a wavelength range between 450 and 637 nm[19]. Later on it became clear that in fact there is an EPR signal even in the absence of light, yet the signal strength is considerably enhanced upon illumination [26]. EPR lines showed either absorptive or emissive line shapes depending on the spectral position. This indicates that only specific spin sub-levels are affected by optical excitation [27]. In general a S = 1 electron spin system is described by a spin Hamiltonian of the following form: e ˆˆˆH g S SDS β=+B . Here g e is the electronic g -factor (g = 2.0028 ± 0.0003); B 0 is the external magnetic field and D is the zero field splitting tensor. This ten-sor comprises the anisotropic dipolar interaction of the two electron spins forming the triplet state aver-aged over their wave function. The tensor is traceless and thus characterized by two parameters, D and E as already mentioned above. The zero field splitting causes a lifting of the degeneracy of the spin sub-levels m s = ±1,0 even in the absence of an external magnetic field. Those zero field spin wave functions T x,y,z do not diagonalize the full high-field Hamiltonian H but are related to these functions by121212=x T T T ββαα-+-=-〉〉,121211y T T T ββαα-++=+〉〉,12120|.z T T αββα+=〉〉 The expectation value of S z for all three wave functions ,,,,||x y z z x y z T S T 〈〉 is zero. Hence there is no magnetization in zero external field. There are different ways to account for the spin polarization process in an excitation scheme involving spin triplets. To first order optical excitation is a spin state conserving process. However spin–orbit (LS) coupling might allow for a spin state change in the course of optical excitation. Cross relaxation processes on the other hand might cause a strong spin polarization as it is observed in the optical excitation of various systems, like e.g. GaAs. However, optical spectroscopy and in particular hole burning data gave little evidence for non spin conserving excitation processes in the NV centre. In two laser hole burning experiments data have been interpreted by assuming different zero field splitting parameters in ground and excited state exc exc (2GHz,0,8GHz)D E ªª by an otherwise spin state preserving optical excitation process [28]. Indeed this is confirmed by later attempts to gener-ate ground state spin coherence via Raman process [29], which only proves to be possible when ground state spin sublevels are brought close to anticrossing by an external magnetic field. Another spin polaris-ing mechanism involves a further electronic state in the optical excitation and emission cycle [30, 31]. Though being weak, LS coupling might be strong enough to induce intersystem crossing to states with different spin symmetry, e.g. a singlet state. Indeed the relative position of the 1A singlet state with re-spect to the two triplet states has been subject of intense debate. Intersystem crossing is driven by LS induced mixing of singlet character into triplet states. Due to the lack of any emission from the 1A state or noticeable absorption to other states, no direct evidence for this state is at hand up to now. However, the kinetics of photo emission from single NV centres strongly suggests the presence of a metastable state in the excitation emission cycle of the state. As described below the intersystem crossing rates from the ex-cited triplet state to the singlet state are found to be drastically different, whereas the relaxation to the 3A state might not depend on the spin substate. This provides the required optical excitation dependent relaxa-tion mechanism. Bulk as well as single centre experiments show that predominantly the m s = 0 (T z ) sublevel in the spin ground state is populated. The polarization in this state is on the order of 80% or higher [27].phys. stat. sol. (a) 203, No. 13 (2006) 3211 © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim4 Spin properties of the NV centreBecause of its paramagnetic spin ground and excited state the NV centre has been the target of numerous investigations regarding its magnetooptical properties. Pioneering work has been carried out in the groups of Manson [32–36], Glasbeek [37–39] and Rand [26, 40, 41].The hyperfine and fine structure splitting of the NV ground state has been used to measure the Aut-ler–Townes splitting induced by a strong pump field in a three level system. Level anticrossing among the m s = 0 and m s = –1 allows for an accurate measurement of the hyperfine coupling constant for the nitrogen nucleus, yielding an axially symmetric hyperfine coupling tensor with A || = 2.3 MHz and A ^ = 2.1 MHz [42, 43]. The quadrupole coupling constant P = 5.04 MHz. Because of its convenient access to various transitions in the optical, microwave and radiofrequency domain the NV centre has been used as a model system to study the interaction between matter and radiation in the linear and non-linear regime. An interesting set of experiments concerns electromagnetically induced transparency in a Λ-type level scheme. The action of a strong pump pulse on one transition in this energy level scheme renders the system transparent for radiation resonant with another transitions. Experiments have been carried out in the microwave frequency domain [44] as well as for optical transitions among the 3A ground state and the 3E excited state [29]. Here two electron spin sublevels are brought into near level anticrossing such that an effective three level system is generated with one excited state spin sublevel and two allowed optical transitions. A 17% increase in transmission is detected for a suitably tuned probe beam.While relatively much work has been done on vacancy and nitrogen related impurities comparatively little is known about defects comprising heavy elements. For many years it was difficult to incorporate heavy elements as impurities into the diamond lattice. Only six elements have been identified as bonding to the diamond lattice, namely nitrogen, boron, nickel, silicon, hydrogen and cobalt. Attempts to use ion implantation techniques for incorporation of transition metal ions were unsuccessful. This might be due to the large size of the ions and the small lattice parameters of diamond together with the metastability of the diamond lattice at ambient pressure. Recent developments in crystal growth and thin film technology have made it possible to incorporate various dopants into the diamond lattice during growth. This has enabled studies of nickel defects [45, 46]. Depending on the annealing conditions Ni can form clusters with various vacancies and nitrogen atoms in nearest neighbour sites. Different Ni related centres are listed with NE as a prefix and numbers to identify individual entities. The structure and chemical compo-k 23k 12k 31k 213A 3E 1AOptical excitation 3A 3E 1A z x,yz´x´y´k 23k 31a bFig. 3 a) Three level scheme describing the optical excitation and emission cycle of single NV centres. 3A and 3E are the triplet ground and excited state. 1A is a metastable singlet state. No information is at hand presently about the number and relative position of singlet levels. The arrows and k ij denote the rates of transition among the various states. b) More detailed energy level scheme differentiating between trip-let sublevels in the 3A and 3E state.3212 F. Jelezko and J. Wrachtrup: Single defect centres in diamond: A review© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim sition of defects have mostly been identified by EPR on the basis of the hyperfine coupling to nitrogen nuclei [46]. A particularly rich hyperfine structure has been identified for the NE8 centre.Analysis of the angular dependence of the EPR spectrum for the NE8 centre showed that this centre has electronic spin S = 1/2 and a g -value typical of a d -ion with more than half filled d -shell. The NE8 centre has been found not only in HPHT synthetic diamonds but also in natural diamonds which contain the nickel-nitrogen centres NE1 to NE3 [46]. The structure of the centre is shown in Fig. 4. It comprises 4 substitutional nitrogen atoms and an interstitial Ni impurity. The EPR signature of the system has been correlated to an optical zero phonon transition at around 794 nm. The relative integral intensity of the zero phonon line and the vibronic side band at room temperature is 0.7 (Debey–Waller factor) [47]. The fluorescence emission statistics of single NE8 emitters shows a decay to a yet unidentified metastable state with a rate of 6 MHz.5 Single defect centre experimentsExperiments on single quantum systems in solids have brought about a considerable improvement in the understanding of the dynamics and energetic structure of the respective materials. In addition a number of quantum optical phenomena, especially when light–matter coupling is concerned, have been investi-gated. As opposed to atomic systems on which first experiments on single quantum systems are well established, similar experiments with impurity atoms in solids remain challenging. Single quantum sys-tems in solids usually strongly interact with their environment. This has technical as well as physical consequences. First of all single solid state quantum systems are embedded in an environment which, for example, scatters excitation light. Given a diffraction limited focal volume usually the number of matrix atoms exceed those of the quantum systems by 106–108. This puts an upper limit on the impurity content of the matrix or on the efficiency of inelastic scattering processes like e.g. Raman scattering from the matrix. Various systems like single hydrocarbon molecules, proteins, quantum dots and defect centres have been analysed [48]. Except for some experiments on surface enhanced Raman scattering the tech-nique usually relies on fluorescence emission. In this technique an excitation laser in resonance with a strongly allowed optical transition of the system is used to populate the optically excited state (e.g. the 3E state for the NV centre), see Fig. 3a. Depending on the fluorescence emission quantum yield the system either decays via fluorescence emission or non-radiatively, e.g. via inter-system-crossing to a metastable Fig. 4 (online colour at: ) Structure of the NE8 cen-tre.phys. stat. sol. (a) 203, No. 13 (2006) 3213© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimF l u o r .I n t e n s i t y ,k C t s /s Excitation power,mW.state (1A in the case of the NV). The maximum numbers of photons emitted are given when the optical transition is saturated. In this case the maximum fluorescence intensity is given as312123F max 3123()=.2k k k I k k Φ++ Here k 31 is the relaxation rate from the metastable to the ground state and k 21 is the decay rate of the opti-cally excited state, k 23 is the decay rate to the metastable state and φF marks the fluorescence quantum yield. For the NV centre I max is about 107 photon/s. I max critically depends on a number of parameters. First of all the fluorescence quantum yield limits the maximum emission. A good example to illustrate this is the GR1 centre, the neutral vacancy defect in diamond. The overall lifetime of the excited state for this defect is 1 ns at room temperature. However, the radiative lifetime is on the order of 100 ns. Hence φF is on the order of 0.01. Given the usual values for k 21 and k 31 this yields an I max which is too low to allow for detecting single GR1 centres with current technology. Figure 5 shows the saturation curve of a single NV defect. Indeed the maximum observable emission rate from the NV centre is around 105 pho-tons/s which corresponds well to the value estimated above, if we assume a detection efficiency of 0.01. Single NV centres can be observed by standard confocal fluorescence microscopy in type Ib diamond. In confocal microscopy a laser beam is focussed onto a diffraction limited spot in the diamond sample and the fluorescence is collected from that spot. Hence the focal probe volume is diffraction limited with a volume of roughly 1 µm 3. In order to be able to detect single centres it is thus important to control the density of defects. For the NV centre this is done by varying the number of vacancies created in the sam-ple by e.g. choosing an appropriate dose of electron irradiation. Hence the number of NV centres de-pends on the number of vacancies created and the number of nitrogen atoms in the sample. Figure 7 shows an image of a diamond sample where the number of defects in the sample is low enough to detect the fluorescence from single colour centres [49]. As expected the image shows diffraction limited spots. From the image alone it cannot be concluded whether the fluorescence stems from a single quantum system or from aggregates of defects. To determine the number of independent emitters in the focal vol-ume the emission statistics of the NV centre fluorescence can be used [50–52]. The fluorescence photon number statistics of a single quantum mechanical two-level system deviates from a classical Poissoniandistribution. If one records the fluorescence intensity autocorrelation function 2()()=()t I t g t ΙττΙ+2〈()〉〈〉 for short time τ one finds g 2(0) = 0 if the emission stems from a single defect centre (see Fig. 6). This is due to the fact that the defect has to be excited first before it can emit a single photon. Hence a single defect never emits two fluorescence photons simultaneously, in contrast to the case when a number of independent emitters are excited at random. If one adopts the three level scheme from Fig. 3a, rate equa-tions for temporal changes of populations in the three levels can be set up. The equations are solved by 12(2)()=1(1)e e ,k k g K K τττ-++Fig. 5 Saturation curve of the fluorescence inten-sity of a single NV centre at T = 300 K. Excitationwavelength is 514 nm. The power is measured atthe objective entrance.3214F. Jelezko and J. Wrachtrup: Single defect centres in diamond: A review © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheimg (2)(τ)τ,nswith rates 1,2=k -P = k 21 + k 12 + k 23 + k 31 and Q = k 31(k 21 + k 12) + k 23(k 31 + k 12) with23231123112= .k k k k k K k k+-- This function reproduces the dip in the correlation function g 2(τ) for τ → 0 shown in Fig. 6, which indicates that the light detected originates from a single NV. The slope of the curve around 0τ= is de-terminded by the pumping power of the laser k 12 and the decay rate k 21. For larger times τ a decay of the correlation function becomes visible. This decay marks the ISC process from the excited triplet 3E to the metastable singlet state 1A. Besides the spin quantum jumps detected at low temperature the photon sta-tistics measurements are the best indication for detection of single centres. It should be noted that the radiative decay time depends on the refractive index of the surrounding medium as 1/n medium . Because n medium of diamond is 2.4 the decay time should increase significantly if the refractive index of the sur-rounding is reduced. This is indeed observed for NV centres in diamond nanocrystals [51]. It should beFig. 7 (onl ine col our at: ) Confocal fl uorescence image of various diamond sampl es with different electron irradiation dosages.Fig. 6 Fluorescence intensity autocorrelation function of a single NV defect at room temperature.phys. stat. sol. (a) 203, No. 13 (2006) 3215 © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheimnoted, that owing to their stability single defect centres in diamond are prime candidates for single pho-ton sources under ambient conditions. Such sources are important for linear optics quantum computing and quantum cryptography. Indeed quantum key distribution has been successful with fluorescence emis-sion from single defect centres [53].A major figure of merit for single photon sources is the signal to background ratio, given (e.g.) by the amplitude of the correlation function at 0τ=. This ratio should be as high as possible to ensure that a single bit of information is encoded in a single photon only. The NV centre has a broad emission range which does not allow efficient filtering of background signals. This is in sharp contrast to the NE8 defect which shows a very narrow, only 1.2 nm wide spectrum. As a consequence the NE8 emission can be filtered out efficiently [47]. The correlation function resembles the one from the NV centre. Indeed the photophysical parameters of the NV and NE8 are similar, yet under comparable experimental conditions the NE8 shows an order of magnitude improvement in signal-to-background ratio because of the nar-rower emission range.Besides application in single photon generation, photon statistical measurements also allow to derive conclusions on photoionization and photochromism of single defects. Most notably the NV centre is speculated to exist in two charge forms, the negatively charged NV with zero phonon absorption at 637 nm and the neutral from NV 0 with absorption around 575 nm [20, 54]. Although evidence existed that both absorption lines stem from the same defect no direct charge interconversion has been shown in bulk experiments. The best example for a spectroscopically resolved charge transfer in diamond is the vacancy, which exists in two stable charge states. In order to observe the charge transfer from NV to NV 0 photon statistical measurements similar to the ones described have been carried out, except for a splitting of photons depending on the emission wavelength [55]. This two channel set up allows to detect the emission of NV 0 in one and NV in another detector arm. Figure 8 shows the experimental result. For delay time 20,()g ττ= shows a dip, indicating the sub-Poissonian statistics of the light emitted. It should -300-200-10001002000,00,40,8g (2)(τ)τ,nsPhotonsDichroicBSStartNV 0Stop NV - Fig. 8 (online colour at: ) Fluorescence cross correlation function between the NV 0 and NV emission of a single defect.。
Antimony in the environment a review focused on natural waters Occurrence
0012-8252r02r$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 2 - 8 2 5 2 Ž 0 1 . 0 0 0 7 0 - 8
Table 1 Antimony abundance
Material
Cosmic abundance Chondrites
Earth-Science Reviews 57 Ž2002. 125–176
rlocaterearscirev
Antimony in the environment: a review focused on natural waters I. Occurrence
Montserrat Filella a,), Nelson Belzile b, Yu-Wei Chen b
126
M. Filella et al.r Earth-Science ReÕiews 57 (2002) 125–176Βιβλιοθήκη 1. Introduction
A good deal of research on geochemical and biogeochemical processes in natural waters has been, and continues to be, devoted to trace elements, particularly transition metals. Rather less attention has been focused on the so-called metalloid elements. Among them, antimony is the one that has received the scantiest attention.
2012最新智商测试题(3篇)
第1篇---2012最新智商测试题样本说明：本测试旨在评估您的认知能力和逻辑思维。
请仔细阅读每个问题，并在规定时间内作答。
所有答案无对错之分，请根据您的直觉和判断选择最佳答案。
一、选择题（每题2分，共20分）1. 下列哪个数字不是偶数？A. 2B. 3C. 4D. 62. 如果今天是星期五，那么7天后是星期几？A. 星期五B. 星期六C. 星期日D. 星期一3. 下列哪个图形与其他三个不同？A. 正方形B. 矩形C. 菱形D. 长方形4. 下面哪个词与其他词不属于同一类别？A. 鸟B. 鱼D. 树木5. 下列哪个数字是质数？A. 8B. 9C. 10D. 116. 如果一个班级有30名学生，其中男生占60%，那么女生有多少人？A. 15B. 18C. 20D. 227. 下列哪个城市不是中国的直辖市？A. 北京B. 上海C. 广州D. 深圳8. 下列哪个字母不是英文字母表中的前10个字母？A. JB. KC. LD. M9. 下列哪个物品不是交通工具？B. 汽车C. 飞机D. 书包10. 下列哪个成语与其他成语意思不同？A. 青出于蓝B. 水滴石穿C. 珠联璧合D. 破釜沉舟二、填空题（每题2分，共10分）11. 2+2=______，5-3=______，8÷2=______。
12. 月球绕地球转一周大约需要______天。
13. 地球绕太阳转一周大约需要______天。
14. 1千克等于______克。
15. 1米等于______厘米。
三、判断题（每题2分，共10分）16. 太阳是行星。
（）17. 水是液体。
（）18. 鸟类都会飞。
（）19. 水可以灭火。
（）20. 火星上有水。
（）四、简答题（每题5分，共20分）21. 请简述地球自转和公转的区别。
22. 请列举三种常见的动物，并说明它们各自的特点。
23. 请简述水循环的过程。
24. 请简述声音是如何传播的。
五、案例分析题（10分）25. 一家工厂在生产一批产品时，发现其中有一部分产品存在质量问题。
EN DIN 10027 Designation systems for steels
DEUTSCHE NORM {© No part of this standard may be reproduced without the prior permission of DIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH , 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).October 2005DIN EN 10027-1English price group 13 www.din.dewww.beuth.de 01.06 9667533Document comprises 25 pages.Designation systems for steelsPart 1: Steel namesEnglish version of DIN EN 10027-1Bezeichnungssysteme für Stähle – Teil 1: KurznamenNational forewordThis standard has been prepared by Technical Committee ECISS/TC 7 ‘Conventional designation of steel’ (Secretariat: Italy).The responsible German body involved in its preparation was the Normenausschuss Eisen und Stahl (Steel and Iron Standards Committee), Technical Subcommittee 19/1 Einteilung, Benennung und Benummerung von Stählen .AmendmentsThis standard differs from the September 1992 edition and DIN V 17006-100, April 1999 edition, as follows.a) The standards have been combined and editorially revised.b) References to steel names as in EU 27-74 have been removed.c) Symbol O for offshore steels has been omitted (table 1).d) Specifications for steels for engineering have been extended to allow for names for steel casting and for steels where impact properties are specified (table 4).e) Steels for or in the form of rails are not designated by their minimum tensile strength, but by their minimum hardness (table 7).f) High strength steel flat products for cold forming are no longer restricted to cold rolled flat products, and four more additional symbols have been included in group 1 (table 9).g) Specifications for tin mill products have been completely revised (table 10).h) Tool steels manufactured by powder metallurgy and high speed steels with the principal symbol PM have been included (tables 14 and 15).i) For alloy steels where the average content by weight of at least one alloying element is ö 5 %, it is now possible to add the chemical symbol and average percentage content for alloying elements that characterize the steel with a content of 0,20 % to 1,0 % (table 14).j) The symbol + CH (for core hardenability) has been included for special requirements (table 16).k) In table 17, the symbol + AR (aluminium rolled) has been omitted.l) In table 18, the symbols + CPnnn (cold work hardened with a minimum 0,2 proof strength of nnn Mpa) and + SR (stress relieved) have been included.Previous editionsDIN EN 10027-1: 1992-09DIN V 17006-100: 1991-10, 1993-11, 1999-04ICS 77.080.20Supersedes September 1992 edition and DIN V 17006-100, April 1999 edition.!,enD"T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3English versionICS 77.080.20 Supersedes CR 10260:1998, EN 10027-1:1992.Management Centre: rue de Stassart, 36 B-1050 BrusselsEuropean Committee for StandardizationComité Européen de NormalisationEuropäisches Komitee für Normung© 2005. CEN – All rights of exploitation in any form and by any means reserved worldwide for CEN national members.Ref. No. EN 10027-1:2005 EÈÉË10027-1August 2005Designation systems for steelsPart 1: Steel namesSystèmes de désignation des aciers – Partie 1: Désignation symbolique Bezeichnungssysteme für Stähle – Teil 1: KurznamenThis European Standard was approved by CEN on 2005-06-27.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member.The European Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland, and the United Kingdom.T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 2 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 3 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 4 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 5 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 6 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 7 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A NV e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3Page 8 EN 10027-1:2005T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V ervielfäl ti gu nglt.DIN-Merkbl att3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3T e c h n i c a l I n f o r m a t i o n C e n t r e M A N V e r v i e l f äl t i g u n g l t . D I N -M e r k b l a t t 3。
NVIDIA MAXIMUS TECHNOLOGY FOR ANSYS MECHANICAL 首次发
DU-06467-001_v01 | August 2012NVIDIA CONFIDENTIAL | Prepared and Provided Under NDA User GuideDOCUMENT CHANGE HISTORYDU-06467-001_v01Version Date Authors Description of Change01 August 3, 2012 Initial releaseTABLE OF CONTENTS Maximus Technology for ANSYS Mechanical (4)Prerequisite Skills (4)What This Document Contains (5)Benefits of Maximus Technology (5)OEMs for Maximus Technology (5)NVIDIA Maximus Technology (6)Maximus Computing Advantage (6)Elements of Maximus Technology (6)Basic Maximus Configuration (8)Maximus for ANSYS Mechanical (9)Enabling ANSYS Mechanical for Maximus (9)Monitoring GPU Activity with Maximus Configuration Utility (11)Supported Solver Types (12)Model Considerations (12)Troubleshooting (13)References (13)This document describes the basic settings, configuration, and monitoring of an NVIDIA® Maximus-enabled workstation for ANSYS Mechanical solvers.This document does not replace any documentation provided by ANSYS for softwareofferings specific to CAE software. Refer to the documentation provided by ANSYS forANSYS software configurations.This document does not explain the fundamentals of ANSYS usage or the discipline ofCAE.PREREQUISITE SKILLSThis document is intended for persons responsible for optimizing a Maximus-enabled workstation for ANSYS Mechanical. It is assumed the audience is familiar with, or has skilled experience with the following:④ANSYS Mechanical CAE Software④Computer Aided Engineering (CAE)④Graphics Processing Unit (GPU) functionality④Modern workstation terminology④Hardware connectivity④Physical system building skills④Thermal and electrical workstation system internals④Microsoft Windows configurationMaximus Technology for ANSYS MechanicalWHAT THIS DOCUMENT CONTAINSThis document provide an introduction to NVIDIA Maximus technology and how to enable your workstation and ANSYS Mechanical to use Maximus.④NVIDIA Maximus Technology starting on page 6 describes the benefits of NVIDIA Maximus technology, its key elements, and the basic system requirements for enabling Maximus on your workstation.④Maximus for ANSYS Mechanical starting on page 9 focuses on using Maximus with ANSYS Mechanical. It explains how to enable Maximus for ANSYS Mechanical and monitor GPU activity. It identifies the solvers that are enabled for Maximus, describes model considerations, and troubleshooting tips when a solver workload does not perform to your expectations.④References on page 13 provides useful references to related documentation. BENEFITS OF MAXIMUS TECHNOLOGYFor a comprehensive overview of Maximus technology, its benefits, and how it is being used, go to /maximus.OEMS FOR MAXIMUS TECHNOLOGYA list of OEMs that carry Maximus platforms are listed at/maximus.This section describes the benefits of Maximus-enabled workstations and applications, the key elements of Maximus technology, and the basic configuration for a Maximus-enabled workstation.MAXIMUS COMPUTING ADVANTAGEIn the past, workstation architectures forced professionals to do graphics-intensive and compute-intensive work serially; often offline. NVIDIA Maximus technology represents a revolution for these professionals by enabling both tasks to be performed concurrently without experiencing any drop in performance.For example; a designer can work on design iteration B while running a simulation on design iteration A. Because these tasks are performed concurrently, it is possible to explore ideas faster and converge more quickly on the best possible answers.ELEMENTS OF MAXIMUS TECHNOLOGYMaximus is an enabling technology that brings together the professional 3D graphics capability of NVIDIA Quadro® GPUs with the massive parallel computing capabilities of the NVIDIA Tesla™ C2075 companion processors. Figure 1 illustrates the advantages of the Tesla processor.Figure 1. Tesla PerformanceFigure 2 shows the performance improvements possible with ANSYS Mechanical on a Maximus-enabled workstation. The Maximus configuration can consist of any of theQuadro cards in the performance scaling chart plus one Tesla card.Figure 2. SolidWorks Scaling ChartBASIC MAXIMUS CONFIGURATIONThis section describes hardware and software requirements for a Maximus-enabledworkstation running ANSYS Mechanical. Only the basic requirements are covered in this document. For further details about upgrading an eligible workstation to aMaximus configuration, refer to the NVI DIA Maximus System Builders’ Guide for Microsoft Windows 7-64 document.Check that your system satisfies the following software and hardware requirements:④Microsoft Windows 7 – 64 bit operating system.④ANSYS Mechanical 14 with HPC License Pack. At the release date of this document, one HPC pack enables eight CPU cores and one entire GPU.④One NVIDIA Quadro card installed in the first x16 (x16 electrical) PCIe slot of the host computer.④One NVIDIA Tesla card installed in the second x16 (x16 electrical) PCIe slot of the host computerAfter ANSYS Mechanical becomes multi-GPU aware and if it is physically possible, youcan have more than one Tesla processor in your system. At the release date of thisdocument, ANSYS Mechanical is still single-GPU aware. Follow future announcementsfrom ANSYS and NVIDIA regarding multi-GPU awareness.At the release date of this document, Tesla C2075 is the only supported compute cardfor ANSYS Mechanical.NVIDIA recommends that no display device be connected to the Tesla C2075 DVI displayoutput.④NVIDIA Quadro/Tesla Driver 275.89, or newer ANSYS-certified driver, correctly installed. Refer to for a list of drivers for download④Correct installation and cabling with power connectors (as needed) of all NVIDIA graphics cards. If you purchased your system from an OEM with the NVIDIA cards pre-installed, no action is needed.No NVIDIA SLI (Scalable Link Interface) ribbon cable is necessary or required for aMaximus configuration.This section explains how to enable Maximus for ANSYS Mechanical and monitor GPU activity. The solvers that can use Maximus are listed and characteristics of models that need to be considered are identified. The section also contains trouble-shooting tips for a solver workload that does not perform to your expectations.ENABLING ANSYS MECHANICAL FOR MAXIMUSUse the following procedure to enable Maximus for ANSYS Mechanical:1.Select Tools from the main menu2.Select Solve Process Settings… to display the Solve Process Settings menu.Maximus for ANSYS Mechanical3.Check that My Computer is selected on the Solve Process Settings menu.4.Click Advanced… to display the Advanced Properties dialog menu.5.Select NVIDIA from the drop-down list of the Use GPU acceleration (if possible) field.6.Click OK.7.Open the ANSYS Mechanical solve.out file to check that Maximus is enabled. Search for the text GPU ACCELERATOR OPTION ENABLED. If this text string is not displayed, Maximus is not enabled.* software license agreement and FAR 12.212 (for non-DOD ** licenses). ** ********************************************************************* ANSYS COMMAND LINE ARGUMENTS *****BATCH MODE REQUESTED (-b) = NOLISTINPUT FILE COPY MODE (-c) = COPY6 PARALLEL CPUS REQUESTEDSTART-UP FILE MODE = NOREADSTOP FILE MODE = NOREADGPU ACCELERATOR OPTION ENABLED00000000 VERSION=WINDOWS x64 RELEASE= 13.0 UP20101012 CURRENT JOBNAME=file 14:22:46 OCT 24, 2011 CP= 0.811Working together with ANSYS Mechanical software, the Maximus driver automatically ensures that ANSYS Mechanical runs on the Tesla GPU. This setting provides the best performance.Monitoring GPU Activity with Maximus Configuration UtilityNVIDIA Maximus Configuration Utility (MCU) is supported for Maximus-enabledworkstations only. Download the MCU from /maximus. The MCUis accessible from in the NVIDIA Control Panel starting with the 304 release of theQuadro drivers.The NVIDIA Maximus Configuration Utility (MCU) is a separate graphical software utility that provides convenient GPU processing controls. The MCU provides GPU memory and utilization monitors for all supported GPUs in a Maximus-enabled system. Typically, MCU is used to ensure that ANSYS Mechanical is using the system GPUs correctly. Figure 3 shows the MCU menu page.Figure 3. NVIDIA Maximus Configuration UtilityIn typical ANSYS Mechanical workflows, you have the option to turn ECC (memory error correction) off. Note that when ECC is on, available memory on the Tesla board is reduced by 13 percent.The MCU provides simple controls to enable or disable computational processing on an installed Quadro GPU. Use this feature to better tune the system for a particular workflow need.Supported Solver TypesANSYS Mechanical uses a companion Tesla GPU with a single job per GPU, for two solver types. The following ANSYS Mechanical solver types are Maximus-enabled:④SMP direct sparse solver④PCG/JCG iterative solverModel ConsiderationsSimulation models have a wide variety of sizes, densities, degrees of freedom, and so on. When running models under a Maximus-enabled configuration, you need to be aware of the following issues:④SMP Direct Sparse Solver Models:●Models with approximately one million to eight million degrees of freedomtypically yield the best acceleration performance.●Any model size is supported. If the computational workload exceeds the 6GB ofmemory of the Tesla C2075, some of the workload may be off-loaded to the CPU.●Models must run in-core (system memory) for the best performance results.●The MSAV option does not apply to SMP direct sparse solver models.④PCG/JCG Iterative Models:●Models with approximately one million to five million degrees of freedom aresupported.●Model size must not exceed the 6GB of memory of the Tesla C2075. Larger modelswill not run.●Models must run in-core. There are no out-of-core options.●Turn off the MSAVE option. Otherwise, the Tesla GPU is ignored. ANSYSWorkbench automatically sets MSAVE for models over 100,000 nodes.Solid structures always provide better performance than shell structures.TROUBLESHOOTINGThere may be times when a solver workload does not perform to your expectations. Following is a list of common items that typically hinder optimal performance of asolver on a Maximus-enabled workstation:④The Tesla C2075 is not set to handle compute tasks.④ECC is turned ON for the Tesla C2075, or the Quadro 6000, or both. While enabling ECC improves accuracy, it slows down performance.④The disk subsystem I/O rate is too slow or bandwidth is constrained.④There is not enough scratch disk space in the system.④The job unexpectedly runs out of core memory.④There is not enough memory in the system.④The ANSYS license does not provide support for Maximus.④The simulation job is too small. See “Model Considerations” on page 10.④MSAVE option is set to ON.④Shell structure models are being used.④More CPUs are being used than necessary for the simulation job. More CPUs do not necessarily add linearly to overall wall clock time performance.REFERENCES④ANSYS Support Documentation: Refer to /Support/Documentation ④NVIDIA Maximus Configuration Guide: Refer to NVIDIA Maximus System Builders’ Guide for Microsoft Windows 7-64NoticeALL NVIDIA DESIGN SPECIFICATIONS, REFERENCE BOARDS, FILES, DRAWINGS, DIAGNOSTICS, LISTS, AND OTHER DOCUMENTS (TOGETHER AND SEPARATELY, “MATERIALS”) ARE BEING PROVIDED “AS IS.” NVIDIA MAKES NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.Information furnished is believed to be accurate and reliable. However, NVIDIA Corporation assumes no responsibility for the consequences of use of such information or for any infringement of patents or other rights of third parties that may result from its use. No license is granted by implication of otherwise under any patent rights of NVIDIA Corporation. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all other information previously supplied. NVIDIA Corporation products are not authorized as critical components in life support devices or systems without express written approval of NVIDIA Corporation.HDMIHDMI, the HDMI logo, and High-Definition Multimedia Interface are trademarks or registered trademarks of HDMI Licensing LLC.ROVI Compliance StatementNVIDIA Products that support Rovi Corporation’s Revision 7.1.L1 Anti-Copy Process (ACP) encoding technology can only be sold or distributed to buyers with a valid and existing authorization from ROVI to purchase and incorporate the device into buyer’s products.This device is protected by U.S. patent numbers 6,516,132; 5,583,936; 6,836,549; 7,050,698; and 7,492,896 and other intellectual property rights. The use of ROVI Corporation's copy protection technology in the device must be authorized by ROVI Corporation and is intended for home and other limited pay-per-view uses only, unless otherwise authorized in writing by ROVI Corporation. Reverse engineering or disassembly is prohibited.OpenCLOpenCL is a trademark of Apple Inc. used under license to the Khronos Group Inc.TrademarksNVIDIA, the NVIDIA logo, Tesla, and Quadro are trademarks and/or registered trademarks of NVIDIA Corporation in the U.S. and other countries. Other company and product names may be trademarks of the respective companies with which they are associated.Copyright© 2012 NVIDIA Corporation. All rights reserved.。
2012年海南高考英语试题和答案
2012年普通高等学校招生全国统一考试（海南卷）英语本试题卷分第I卷(选择题）和第II卷(非选择题)两部分。
考生作答时，将答案答在答题卡上(答题注意事项见答题卡)，在本试题卷上答题无效。
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第一节(共5小题:每小题1.5分，满分7.5分）听下面5段对话。
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例：How much is the shirt?A. ￡19.15.B. ￡9.15C. ￡9.18答案是B。
1. Where does this conversation probably take place?A. In a bookstore.B. In a classroomC. In a library.2. At what time will the film begin?A. 7:20.B. 7:15.C. 7:00.3. What are the two speakers mainly talking about?A. Their friend Jane.B. A weekend trip.C. A radio programme.4. What will the woman probably do?A. Catch a train.B. See the man off.C. Go shopping.5. Why did the woman apologize?A. She made a late delivery.B. She went to the wrong place.C. She couldn't take the cake back.第二节(共15小题:每小题1.5分，满分22.5分)听下面5段对话。
Microfluidics The no-slip boundary condition
a r X i v :c o n d -m a t /0501557v 3 [c o n d -m a t .s o f t ] 28 S e p 2005To appear as Ch.15in Handbook of Experimental Fluid Dynamics Editors J.Foss,C.Tropea and A.Yarin,Springer,New-York (2005).Microfluidics:The No-Slip Boundary ConditionEric Lauga †,1,Michael P.Brenner ‡and Howard A.Stone ††Division of Engineering and Applied Sciences,Harvard University ,29Oxford Street,Cambridge,MA 02138,†lauga@,‡brenner@,††has@.September 28,2005AbstractThe no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid me-chanics.However,this condition is an assumption that cannot be derived from first principles and could,in theory,be violated.In this chapter,we present a review of recent experimental,numerical and theoretical investigations on the subject.The physical picture that emerges is that of a complex behavior at a liquid/solid interface,involving an interplay of many physico-chemical parameters,including wetting,shear rate,pressure,surface charge,surface roughness,impurities and dissolved gas.Contents1Introduction22History of the no-slip condition22.1The previous centuries .........................................22.2Terminology ...............................................32.3Traditional situations where slip occurs ...............................42.4Newtonian liquids:No-slip?Slip?...................................43Experimental methods53.1Indirect methods ............................................53.2Local methods .............................................84Molecular dynamics simulations94.1Principle .................................................94.2Results ..................................................104.3Interpretation in the continuum limit .................................105Discussion:Dependence onphysical parameters 115.1Surface roughness ............................................115.2Dissolved gas and bubbles .......................................125.3Wetting .................................................145.4Shear rate ................................................155.5Electrical properties ..........................................165.6Pressure .................................................166Perspective171IntroductionThe vast majority of problems in the dynamics of Newtonianfluids are concerned with solving,in particular settings,the Navier-Stokes equations for incompressibleflowρ(∂t+u·∇)u=−∇p+µ∇2u,∇·u=0.(1) The list of problems for which this task has proven to be difficult is long.However,most of these studies assume the validity of the no-slip boundary condition,i.e.,that all three components of thefluid velocity on a solid surface are equal to the respective velocity components of the surface.It is only recently that controlled experiments,generally with typical dimensions microns or smaller,have demonstrated an apparent violation of the no-slip boundary condition for theflow of Newtonian liquids near a solid surface.We present in this chapter a tentative summary of what is known about the breakdown of the no-slip condition for Newtonian liquids and discuss methods and results of experiments,simulations and theoretical models.This topic is of fundamental physical interest and has potential practical consequences in many areas of engineering and applied sciences where liquids interact with small-scale systems[147,149],includingflow in porous media,microfluidics,friction studies and biologicalfluids.Furthermore,since viscousflows are relevant to the study of other physical phenomenon,such as the hydrophobic attraction in water,a change in the boundary condition would have significant quantitative impact on the interpretation of experimental results[174,175,177].The present chapter complements previous work[63,153,176]and is organized as follows.In§2we present a brief history of the no-slip boundary condition for Newtonianfluids,introduce some terminology, and discuss cases where the phenomenon of slip(more appropriately,this may often be“apparent slip”)has been observed.In§3we present the different experimental methods that have been used to probe slip in Newtonian liquids and summarize their results in the form of tables.A short presentation of the principle and results of Molecular Dynamics simulations is provided in§4,as well as remarks about the relation between simulations and experiments.We then present in§5an interpretation of experimental and simulation results in light of both molecular and continuum models,organized according to the parameters upon which slip has been found to depend.We conclude in§6by offering a brief perspective on the subject.2History of the no-slip condition2.1The previous centuriesThe nature of boundary conditions in hydrodynamics was widely debated in the19th century and the reader is referred to[60,61]for historical reviews.Many of the great names influid dynamics have expressed an opinion on the subject at some point during their careers,including D.Bernoulli,Euler,Coulomb,Darcy, Navier,Helmoltz,Poisson,Poiseuille,Stokes,Hagen,Couette,Maxwell,Prandtl and Taylor.In his1823 treatise on the movement offluids[115],Navier introduced the linear boundary condition(also proposed later by Maxwell[109]),which remains the standard characterization of slip used today:the component of thefluid velocity tangent to the surface,u ,is proportional to the rate of strain,(or shear rate)at the surface,2u =λn·(∇u+(∇u)T)·(1−nn),(2) where n denotes the normal to the surface,directed into the liquid.The velocity component normal to the surface is naturally zero as mass cannot penetrate an impermeable solid surface,u·n=0.In Eq.(2),λhas the unit of a length,and is referred to as the slip length.For a pure shearflow,λcan be interpreted as thefictitious distance below the surface where the no-slip boundary condition would be satisfied(see Fig.1). Note that on a curved surface the rate of strain tensor is different from the normal derivative of the tangential component of theflow so all the terms in Eq.(2)need to be considered[49].A century of agreement between experimental results in liquids and theories derived assuming the no-slip boundary condition(i.e.,λ=0)had the consequence that today many textbooks offluid dynamics fail toFigure1:Intepretation of the(Maxwell-Navier)slip lengthλ.mention that the no-slip boundary condition remains an assumption.A few monographs however discuss the topic.In his classic book[98](p.576),Lamb realizes that no-slip is the most probable answer but leaves the possibility open for extraordinary cases:It appears probable that in all ordinary cases there is no motion,relative to the solid,of thefluid imme-diately in contact with it.The contrary supposition would imply an infinitely greater resistance to thesliding of one portion of thefluid past another than to the sliding of thefluid over a solid.Similarly,Batchelor[8](p.149)offers two paragraphs where the question is discussed in detail,including the role of molecular effects in smoothing out discontinuities.He also mentions the importance of an experimental validation of the no-slip condition:The validity of the no-slip boundary condition at afluid-solid interface was debated for some years duringthe last century,there being some doubt about whether molecular interactions at such an interface leadto momentum transfer of the same nature as that at a surface in the interior of afluid;but the absenceof slip at a rigid wall is now amply confirmed by direct observations and by the correctness of its manyconsequences under normal conditions.2.2TerminologyWe introduce here some useful terminology that is used throughout this chapter.•Phenomenon of slip:Refers to any situation in the dynamics offluids where the value of the tangential component of the velocity appears to be different from that of the solid surface immediately in contact with it.•Molecular slip(also intrinsic slip):Refers to the possibility of using hydrodynamics to force liquid molecules to slip against solid molecules.Such a concept necessarily involves large forces[153].Let us denote byσa typical molecular length scale and by A the Hamaker constant for the intermolecular forces.Molecular slip will occur when intermolecular interactions O(A/σ)are balanced by viscous forces O(µσ2˙γ)whereµis the shear viscosity of the liquid and˙γthe shear rate;this can only happen for a very large shear rates˙γ≈A/µσ3∼1012s−1,where we have taken the viscosity of waterµ=10−3Pa·s, and typical values A≈10−19J andσ≈0.3nm.•Apparent slip:Refers to the case where there is a separation between a small length scale a where the no-slip condition is valid and a large length scale L≫a where the no-slip condition appears to not be valid.Well-known examples of such apparent slip include electrokinetics[138](in this case a is the the thickness of the double layer)and acoustic streaming[8](in this case a is the thickness of the oscillatory boundary layer).Similarly,a liquidflowing over a gas layer displays apparent slip(see§5).•Effective slip:Refers to the case where molecular or apparent slip is estimated by averaging an appro-priate measurement over the length scale of an experimental apparatus.2.3Traditional situations where slip occursThe phenomenon of slip has already been encountered in three different contexts.Gasflow.Gasflow in devices with dimensions that are on the order of the mean free path of the gas molecules shows significant slip[113].An estimate of the mean free path is given by the ideal gas formula ℓm≈1/(√ℓm =2(2−p)Table1:Summary of slip results for pressure drop versusflow rate experiments.The following symbolsare used in this table:−:unknown parameter;DDS:dimethyldichlorosilane;TMS:trimethylchlorosilane; CTAB/CTA(+):cetyltrimethyl ammonium bromide;PVP:polyvinylpyridine;OTS:octadecyltrichlorosilane;CCl4:tetrachloromethane;SDS:sodium dodecyl sulfate;pp:peak to peak;rms:root mean square;L:slipindependent of shear rate;NL:shear rate dependent.studies reporting some degree of slip[21,34,46,141,160].In part,this chapter is an attempt to describe and interpret these more recent experimental results.3Experimental methodsAs will be discussed below,a large variability exists in the results of slip experiments so it is important to first consider the different experimental methods used to measure slip,directly or indirectly.In these setups,surface conditions may usually be modified by polymer or surfactant adsorption or by chemical modification.Two broad classes of experimental approaches have been used so far,indirect methods and local methods. 3.1Indirect methodsIndirect methods assume Eq.(2)to hold everywhere in a particular configuration and inferλby measuringa macroscopic quantity.Such methods report therefore effective slip lengths,and they have been the mostpopular so far.If the effective slip length isλ,then a system size L at least comparable L∼λis necessary in order for slip to have a measurable impact.Pressure drop versusflow rate.This standard technique is used in many studies[30,32,34,88,141],where the main results are summarized in Table13.A known pressure drop∆p is applied between the two ends of a capillary or a microchannel and theflow rate Q= u d S is measured.A slip boundary condition leads to aflow rate,Q(λ),larger then the no-slip one,Q NS,by a factor that varies with the ratio of the sliplength to the system size;e.g.,for a circular pipe of radius a,we getQ(λ)a·(4) Using this method,we also note that two groups have reported a larger resistance than that expected with the no-slip condition in microchannels[122]and forflow through small orifices[65].Their results are not well understood but might be due to electrokinetic effects orflow instabilities.Table 2:Summary ofalternative experimental methods to infer slip.The symbols used in this table are given in Table 1,with additional symbols as:S:sedimentation;FR:fluorescence recovery;PIV:particle image velocime-try;SP:streaming potential;FC:fluorescence cross-correlations;DETMDS:diethyltetramethyldisilazan;FDS:perfluorodecanetrichlorosilane;STA:stearic acid (octadecanoic acid);CDOS:chlorodimethyloctylsilane;Va:vacuum;PDMS:polydimethylsiloxane;KCl:potassium chloride;NaCl:sodium chloride.Drainage versus viscous force.This technique consists in imposing the motion (steady or oscillatory)of a curved body perpendicular to a solid surface,and measuring the instantaneous resistive force,which may be compared with that from a model of the fluid motion in the gap,assuming no-slip or slip boundary conditions [64,121,131].This method is similar in principle to the pressure drop vs.flow rate method,with the difference that,here,the pressure and velocity fields are unsteady.The two most common narrow-gap geometries are either a sphere of radius a close to a planar surface or two crossed cylinders of radius a .For both cases,the viscous force F opposing the motion has the form [172]F =−f ∗6πµa 2V3λ1+DD−1,(6)and has been extended to account for two different slip lengths [172]and for the case of any curved bodies [173].Note that when D ≪λ,f slip goes to zero as f slip ∼D ln(6λ/D )/3λ,so that the viscous force,Eq.(5),only depends logarithmically on D ;this is a well-known result in the lubrication limit [59].Two different experimental apparati have been used to measure drainage forces,the Surface Force Appa-ratus (SFA)and the Atomic Force Microscope (AFM).The SFA was invented to measure non-retarded van der Waals forces through a gas,with either a static or dynamic method [81,154],and was extended in [79]to measure forces between solid surfaces submerged in liquids.More recently it has been used by many groups to measure slip in liquids,with results summarized in Table 3.This technique usually uses interferometry to report the separation distance between the smooth surfaces.The moving surface is attached to a spring system of known properties so the difference between imposed and observed motions allows a calculation of the instantaneous force acting on the surfaces.The AFM was invented by Binnig,Quate and Gerber [11]and has also been used for many investigations of slip,with experimental results summarized in Table 4.A flexible cantilever beam (typically,microns wideTable3:Summary of slip results for experiments using the Surface Force Apparatus(SFA).The symbols used in this table are given in Tables1and2,with additional symbols as:HDA:1-hexadecylamine;OTE: octadecyltriethoxysilane;PPO:polysytrene(PS)and polyvinylpyridine(PVP),followed by coating of OTE; PVP/PB:polyvinylpyridine and polybutadiene;PVA:polyvinylalcohol;OMCTS:octamethylcyclotetrasilox-ane;av:average;th:polymer thickness.Note that many entries in this table,including the largest slip lengths, are from the same group(S.Granick,U.Illinois).and hundreds of microns long)with a small(tens of microns)attached colloidal sphere is driven close to a surface,either at its resonance frequency or atfixed velocity,and the deflections of the beam are measured. Since the mechanical properties of the beam are known,deflection measurements can be used to infer the instantaneous drainage force on the colloidal particle.Sedimentation.This experimental method was used in[16],with their results summarized in Table2.The sedimentation speed under gravity of spherical particles of radius a is measured.If the particles are small enough,their motion will occur at small Reynolds number;in that case,the sedimentation velocity with a slip lengthλ,v(λ),is larger than its no-slip counterpart,v NS,according tov(λ)1+2λ/a·(7) Streaming potential.This is the experimental technique employed in[33],with their results summarized in Table2.A pressure drop is applied to an electrolyte solution between the two ends of a capillary and creates a netflow.Since the surfaces of the capillary acquire in general a net charge in contact with the electrolyte, the net pressure-drivenflow creates an advection-of-charges current which results in a surplus of ions on one end of the capillary,and a deficit in the other end.If the two ends of the capillary are not short-circuited, a net steady-state potential difference,termed the streaming potential,exists between the two ends of theTable4:Summary of slip results for experiments using the Atomic Force Microscope(AFM colloidal probe). The symbols used in this table are given in Tables1-3,with additional symbols as:KOH:potassium hydroxide; HTS:hexadecyltrichlorosilane.capillary and is such that the current due to advection of net charge near the solid surfaces is balanced by the conduction counter-current in the bulk of the electrolyte[23,74,132,138].If thefluid experiences slip at the wall(and if theζ-potential is unchanged by the treatment of the surface),a larger current will occur,hence a large potential difference∆V(λ)given by∆V(λ)2µd ph2+2λResultsǫKoplik[94]HML BF15360−79◦ 1.2no-slip except at CLHeinbuch[66]FL BF915Complete0.8-2−2σ λ 0Thompson[156]FL CF672-53760−90◦ 1.4no-slip except at CLKoplik[95]HML BF/CF1536-80000−80◦ 1.2λ≈0−10σThompson[157]HML CF672 90◦ 1.1λ≈0−2σSun[151]HML BF7100−1no-slip except for frozen wallThompson[158]FL CF1152-17280−140◦ 1.1λ≈0−60σBarrat[7]FL BF/CF1000090−140◦1λ≈0−50σJabbarzadeh[82]HML CF−Complete9λ≈0−10nmCieplak[35]HML BF/CF−− 1.1λ≈0−15σFan[52]HML BF3800-21090Complete−λ≈0−5σSokhan[145]NN BF2000−−λ≈0−5nmCottin-Bizonne[37]FL CF−110−137◦1λ≈2−57σGalea[55]HML CF6000Complete1−3σ λ 4σNagayama[114]FL BF24000−180◦−λ≈0−100nmCottin-Bizonne[36]FL CF−110−137◦1λ≈0−150σ= j F ij,(10)d t2where m i is the atomic mass,r i the position of atom i ,and F ij the interatomic (or intermolecular)force between atoms i and j ,that is F ij =−∇i V ij where V ij is the interaction potential.Potentials used in simulations range from the Lennard-Jones two-body potentialV ij =ǫσr ij 6,(11)where ǫis an energy scale,σthe atomic size,and r ij the distance between atoms i and j,tomorerealisticpotentialsincludingmany-bodyororientation-dependentinteractions[2,92,135].ThesetofEqs.(10)areintegrated intime,withappropriatenumericalcut-offs,andwithspecifiedboundary conditionsandinitialconditions.Usually initial positions are random and initial velocities are taken from a Boltzmann distribution.It is also possible to modify Eq.(10)slightly to model evolution at constant temperature either by coupling the system of atoms to a heat bath or by a proper rescaling of the velocities at each time step.Interactions with a solid can occur by adding different wall atoms,either fixed on a lattice or coupled to a lattice with a large spring constant,to allow momentum transfer from the liquid but prevent melting.The constants (c ij )in Eq.(11)allow variation of the relative intermolecular attraction between liquids and solids,which therefore mimicks wetting ing a simple additive model [78],the case of a partially wetting fluid with contact angle θc can be modeled withcos θc =−1+2ρS c LSmσ2/ǫ(∼10−12s).Simulated systems are therefore limited to tens of nanometers,and times scales to nanoseconds.The conse-quence of this observation is that MD simulations always probe systems with much higher shear rates than any experimental setup.For example,in MD simulations of Couette flow,the typical wall velocity is U ∼σ/τ,corresponding to typical shear rates ˙γ∼σ/τh where h is the typical length scale of the simulation box,usually a few tens of σ.Consequently,˙γ∼1011s −1,which is orders of magnitude larger than experimental shear rates.Note that this does not apply to investigations inferring slip length from equilibrium simulations [14,15].A second significant issue in interpreting results of MD simulation was pointed out by Brenner and Ganesan in the case of particle diffusion near a solid surface [19],and concerns the scale separation between molecular and continuum phenomena.The idea is that the correct boundary condition in the continuum realm should arise asymptotically as a matching procedure between the outer limit of the inner (molecular)system and the inner limit of the outer (continuum)system.By doing so,the change in the physical behavior within a fewintermolecular length scales of the surface is explicitly taken into account,which allows to make a distinction between conditions at a boundary and boundary conditions.As a consequence,slip lengths should not be measured literally at the molecular scale but arise as the extrapolation,at the boundaries,of the farfield hydrodynamic results,a procedure which is not always performed appropriately.5Discussion:Dependence on physical parametersHaving described the different methods by which slip is investigated,we present in this section a discussion of both experimental and simulation results and compare them with theoretical models.The discussion is organized according to the physical parameters upon which slip has been found to depend.5.1Surface roughnessRoughness influences resistance.Be it at the molecular size[55]or on larger scales[17,58,82,125,194], roughness and geometrical features have been observed to influence the behavior at liquid-solid interfaces.Not only does roughness leads to an ambiguity as to the exact location of the surface,but it impacts the dynamics of the nearbyfluid,leading experimentally either to an increase[58,82,125,194]or a decrease[17]of friction with roughness.Roughness decreases slip.The physical idea for a roughness-induced resistance is straightforward:on the roughness length scale,aflow is induced that dissipates mechanical energy and therefore resists motion. For the same reason,a bubble with a local no-shear surface rises at afinite velocity in a liquid.More generally,geometrical features of size a on a surface can be solely responsible for a large resistance on large scales L≫a,independently of the details of the local boundary condition on the scale a.This feature was first recognized by Richardson[134]who assumed a periodic perfectly-slipping surface shape and performed asymptotic calculations for the limit a/L→0;in this limit the no-slip boundary condition was recovered(see also[117,118]).The calculation was revisited by Jansons[84]who considered a small fraction c of roughness elements of size a with a local no-shear condition on an otherwise perfectly slipping surface.Equating the viscous force associated with the disturbanceflow created by the defects,O(µ˙γd2),to the local Stokes drag on a defect,O(µau s),where d∼a/c1/2is the typical distance between defects and u s is thefluid velocity near the defects,leads to an effective slip length for the surface,λ=u s/˙γ,given byaλ∼p<−γ(1+r cosθc)/a,which,for a given value of the pressure,will occur if the surface is hydrophobic (cosθc<0)and a is small enough.The super-hydrophobic state is therefore due to a combination of geometry and wetting characteristics.This idea is related to the so-called fakir droplets[10,27,119,186]and to more general drag reduction mechanisms found in nature using gas bubbles[24].Trapped bubbles in rough surfaces were studied by[70] in the context of contact line motion and are probably responsible for the apparent slip lengths reported in [182,183,184]forflow over fractal surfaces,and possibly other studies as well(see also[101]).A similar mechanism was quantified experimentally using trapped bubbles in rough silicon wafers[120](see also the calculations in[180])and show promise of decreasing turbulent skin-friction drag[112].5.2Dissolved gas and bubblesSlip depends on dissolved gas.The amount of slip has been observed experimentally to depend on the type and quantity of dissolved gas.It is reported in sedimentation studies[16]that slip was not observed in vacuum conditions but only when the liquid sample was in contact with air.Furthermore,the study in[63] showed that tetradecane saturated with CO2lead to results consistent with no-slip but significant slip when saturated with argon,whereas the opposite behavior was observed for water.Similar results were reported in [161].More generally,slip results in non-wetting systems are found to depend strongly on the environment in which the experiment is performed[38].Flow over gas:Apparent slip.The results above,together with experiments showing dependence of slip on the absolute value of the pressure[161],and spatially-varying velocityfields[163],hint at the possibility of flow over surface-attached gas pockets or bubbles(see also the discussion in[101]).Recent results in[38]also point at the possibility offlow over gas pockets associated with the contamination of hydrophobic surfaces by nanoparticles.We also note that the group of Steve Granick reported a contamination of their previous ostensibly smooth mica surfaces by platinum nanoparticles[104],possibly affecting some of their experimental results in[192,193,194,195].The idea of aflow over a gas layer wasfirst mentioned in[137]and revisited in[136]as a possible explanation for the attraction between hydrophobic surfaces in water:the attraction could be due to the hydrodynamic correlatedfluctuations of the gas interfaces,analogous to the Bjerknes force between two pulsating bubbles. Detailed theoretical considerations have shown that it would be favorable for water between two hydrophobic surfaces to vaporize[107].Flow of binary mixtures have also been shown to phase separate by the sole action of intermolecular forces[4].It is clear thatflow over a layer of gas will lead to an apparent slip.Since stress must be continuous at a liquid-gas interface,a difference of shear viscosities will lead to a difference of strain rates.If a liquid of viscosityµ1flows over a layer of height h with viscosityµ2,the apparent slip length for theflow above is(see, e.g.,[172])λµ2−1;(15)µ1/µ2≈50for a gas-water interface.Three differences exist however between aflow over a gas layer and flow over a set of bubbles:(a)The gas in bubbles recirculates,which decreases the previous estimate Eq.(15) by about a factor of four;(b)No-slip regions located between the bubbles will also significantly decrease the apparent slip lengths[84,101,123,124,134](see also[1]on the effect of non-uniform slip lengths);(c)Bubbles are in general notflat,which decreases the previous estimates even further(similar to the effect of roughness on a shearflow).When the gas layer is in the Knudsen regime(σ≪h≪ℓm),the shear stress in the liquid,O(µ˙γ),is balanced by a purely thermal stress in the gas,O(ρu s u th),whereρis the gas density,u th the thermal velocity u th=O(,(16)ρu thwhich is independent of h and can be as large as microns.Note that the slip length given by Eq.(16)increases with the viscosity of the liquid.1010101010θ (°)λ(n m )1010101010γ (s -1)λ(nm)Figure 2:Experimental variation of the slip length,λ,with the liquid-solid contact angle,θ(left),and the typical experimental shear rate,˙γ(right),for the experimental results summarized in Tables 1-4:Pressure-driven flow (◦),sedimentation (•),fluorescence recovery ( ),PIV (◮),streaming potential ( ),fluorescence cross-correlations (◭),SFA ( ),and AFM (⊲).When a solid line is drawn,the experimental results are given for a range of contact angles and/or shear rates.Furthermore,when the value of the contact angle is unknown,the results are not reported.Nanobubbles in polar liquids?Over the last four years,many groups have reported experimental obser-vation of nanobubbles against hydrophobic surfaces in water [5,71,76,106,144,148,152,165,166,191,190],with typical sizes ∼10−100nm and large surface coverage (see also the reflectivity measurements in [85,143]).The nanobubbles disappear when the liquid is degassed.Similar bubbles could be responsible for slip mea-surement in some of the experiments to date (see also [179,187]).How could the formation of such bubbles beexplained?Thermal fluctuations lead to bubble sizes a ∼ Dc 0RT1+p 0a。