Connectivity alterations assessed by combining fMRI and MR-compatible hand robots in chronic stroke

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Chapter 2. Adaptive Reuse from Architectural PerspectivesAdaptive reuse of historic buildings is a way of maintainingvalues of architectural heritage while supporting current andfuture development. Conventionally taken as a compromise ofsafeguarding the past, adaptive reusealso implies a road to thefuture. This chapter explores the history and approaches ofadaptive reuse in a global context and multi-disciplinaryperspectives by addressing the threekey conceptsadaptivereuseinvolves – heritage conservation, architectural productionand urban development.1. Adaptive Reuse as an Approach towards HeritageConservation1.1Heritage ValuesAltering existing buildings for new functions is not a newphenomenon. The difference between building conversion andadaptive reuse is that the former was done in a pragmatic waywhich was oftendisregards of the history or architecturalcharacters of the buildings. Whereas adaptive reuse isconducted with the consideration of heritage values of thehistoric buildings.The first systematic analysis of heritage values was done byAloisRiegl (1858-1905), an art historian, and the GeneralConservator of the Central Commission in Austria. As a part ofthe attempts to reorganize the Austrian conservation services,Riegl was commissioned to write a study to define thetheoretical aspects of the work. The results of this study werepublished as The modern cult of monuments: its character andits origin. Riegloutlined the values and concepts whenapproaching conservation of historic buildings.Table 1: Summary of types of values of monuments defined by AloisRiegl.1The differences of values may result in different conservation approaches. For instance, “historical value” referred to a particular, individual stage of a monument, while “age-value” is more comprehensive in considering age, colour and form (Table 1) .The interpretation is more complicated where the …use-value‟ comes into play.“Where a monument has ceased to have …use-value‟, the consideration of …age-value‟ has begun to prevail in its preservation… most would prefer to regard a building in use as something sturdy rather than as something ages and decayed.” Compared with other conservation approaches, adaptive reuse addresses particularly the “use-value”. Regarding the existing use value of historic buildings, Riegl said: “an old building still in use must be maintained in such a condition that it can accommodate people without endangering life or health… practical considerations allow age-value only in a few exceptional cases”.2Age-valueVSHistorical valueUse-valueVSHistoric-value, Age-valueThe contradiction between “newness-value”and “age-value”was regarded by Rieglas the central controversy that raged over the treatment of monuments.3A dichotomy exists where on the one hand there is an appreciation of the old,a view that discouragesany renovation of the old in principle; on the other hand there is an appreciation of the new,a view that seeks to remove all traces of age as disturbing and non-contemporary.Newness-value VSAge-value1.2ArchitecturalPrinciples for Adaptive ReuseTo balance different values of historic buildings while adapting them for new uses, contemporary conservation discipline adopts some basic principles to control the interventions to historic buildings. The following section gives a brief introduction of those principles.Compatibility of UseThe future use(s)of the historic buildings should be compatible with its historic value and architectural character. What does compatibility mean? It is defined in Burra Charter (mentioned in Chapter 1) that “new use of a place should involve minimal change to significant fabric and use; should respect associations and meanings; and where appropriate should provide for continuation of activities and practices which contribute to the cultural significance of the place”.4Minimal ImpactAdaptive reuse is based on the respect for the historical building fabric and significance . Changes are necessary not only to fulfil the future use, but sometimes also to retain the historic value. The changes made to anexisting building should in principle be “as much as necessary but as little as possible”. Any changes should be guided by the assessment of its cultural value and appropriate interpretation. It is explained in Burra Charter that “Changes to a place should not distort the p hysical or other evidence it provides, not be based on conjecture”.5“New work such as additions or other changes to the place may be acceptable where it respects and does not distort or obscure the cultural significance of the place, or detract from itsi nterpretation and appreciation”.6RecognisabilityTo retain authenticity, the changes made to the existing building should be recognisable. Imitation of architectural motives and featuresshould generally be avoided. Even the alterations in history should b e treated cautiously because “the traces of additions, alterations and earlier treatments to the fabric of a place are evidence of its history and uses which may be part of its significance. Conservation action should assist and not impede their understand ing”.7ReversibilityWhen changes that would reduce the cultural significance of the buildings have to be made due to practical reasons, they should be reversible, and be reversed when circumstances permit. To find the best way of adapting the buildings while minimises the reduction of its value, different options should be explored. “Non-reversible change should only be used as the last resort and should not prevent future conservation action”.8These principles will be further illustrated with examples in the next section.2.Adaptive Reuse as an Activity of ArchitecturalProductionThe very basic aim of adaptivereuse is to retain the valued component of the past whilst meet the needs of changing patterns of the future. This doesnot necessarily mean to restrict the scale and expression of new structures. Different from repair and restoration, adaptive reuseopens the way of integrating conservation into the art of architecture. Adaptive reuse of historic buildings can beintriguingand unique. This may be caused by constraints posed by the original building, whichcan stimulate unconventional designs. Therefore,not only adaptive reuse projects thatsensitively keep the original presence of historicvaluesare appreciated, we are also impressed by creative projects that bring new experiencesto people with outstanding architectural expressions.2.1Factors Affecting Architectural InterventionsHow do weallow a new function or a new experience to happen in an adapted and intervened building while retaining its original characters? The process of adapting historic buildings usually begins with the understanding of their characters. The key to adapt existing buildings without compromising theirunique characters hinges on the accuracy and comprehensiveness of the assessment and understanding of the to-be-adapted buildings. The defined features of the historic structure are like “bones” that should accommodate new programmes. How to do this largely depends on the creative mind of the architect. Of course the requirements of urban planning and building regulations are all relevant limitations. Same as architectural production of new buildings, adaptive reuse is also a creative process that cannot be assessed by objective criteria alone. Attitudes towards architectural interventions in adaptive reuse such as preferences of stakeholders and values held by the society are influential subjective factors which could lead to a variety of approaches in projects. Viewing from a historical perspective, architectural conservation as a modern professional always reflected the values of a society at certain time.2.2Different Architectural InterventionsThere are many approaches to classify different architectural interventions in adaptive reuse of old buildings. Most of the approaches are based on the physical composition of the original and new structures. However, neither form nor material (the two basic aspects of architecture) can be indicated in such approaches.Fig. 2-1 Adaptive reuse taxonomies defined by Kelly Goffiney.9wraps weavings juxtapositions parasites insertionsFig. 2-2 The five categories of adaptive reuse defined by Françoise Bollack.10Hence, physical combination of old relics and new constructions can hardly reflect the performance of the intervention and the character of the space. In view of this, we categorise different approaches by interaction between the old and new parts. Three approaches are defined according to the paradigm of the interaction, which are (1) integration; (2) complementary; and (3) association.Original IntergrationComplementary Association Fig.2-3 The classification according to the interactions between old and new aspects.The approach of integration is to conserve the building to the largest extent. It denotes a change in appearance, form or structure which embraces the building in its entirety; the boundary between old and new is thereby dissolved.By complementary, although new and old parts are clearly defined, the incorporation of the newly built sections with the old aspects such as form and material creates continuity with the existing structures. Despite it seems the adapted building is shown in a contemporary form with added structures, the historic aura of the adapted building is not infringed.The approach of association is viewed as the most innovative and adventurous among the three approaches. It transforms old buildings, stressing contrast, dichotomy or even dissonance. By association, no attempt will be made to show what exists originally.After a brief introduction of the three approaches of interventions of buildings in adaptive reuse, examples were selectedto illustrate these approaches in a more comprehensive manner.Integration: Renovation of Vegetable and Grain Silos into Offices in Helsinki, FinlandIt might be hard to imagine how silo, a typical infrastructure for industry or agriculture, is adaptively reused. In Helsinki, the conversion of vegetable and grain silo into the office of a government agency in 200311 shows us the potential of utilising this kind of industrial heritage. The complex consists of a red brick warehouse, a characteristic feature of the old industrial Helsinki seascape and a group of silos. To preserve theindustrial characters of the complex, which anchors its city block located in an industrial district, a new brick addition that faces the street was constructed in the same proportion as the existing warehouse. The narrow windows of the warehouse were enlarged in such a way that the characteristics of the façade stay essentially the same. The silos were turned into elevator shafts and service core, with the offices opened to the courtyard behind.12 The original monumental character of the building has been preserved by tearing down the courtyard elevations thus opening up the offices inside the block towards the South. The modern office concept of emphasising transparency has been set in the old industrial milieu. The massive brick walls, the concrete silos and the dense grid of mushroom pillars of the former warehouse create a unique frame for the architecture of the offices.purpose of unifying the character, the approach of integration presents grated appearance of the historic structure as much as possible. the consideration of the context, this integrated approach is often ed on historic monuments with highly historic values. The historic e for such kind of intervention should be in good condition with high Fig. 2-4 The red brick warehouse and the concrete silos. The part on the left is added.By JussiTiainen.Fig. 2-5 The Inner courtyard of the complex. By JussiTiainen.eness and integrity. Otherwise, the restored or interpreted parts shoulddocumented to avoid inaccurate reconstruction. The physical renewaluilt substance is often more subtle but probably more far-reaching thanplementary” or “association”.Figure 2-6. The mushroom pillarsand the glass wall towards innercourtyard. By JussiTiainen.Complementary: Andalusian Historical Heritage Institute,SpainThe headquarters of Andalusian Historical Heritage Institutewas a ceramics factory on La Cartuja island at Seville. Thefactory itself was a reuse of a fourteenth-century monasticcomplex in mid 19th century. Abandoned in 1982, the site wasrehabilitated in the 1990s by the Andalusian government.The core of the factory was the cloister of the early monastery (Fig. 2-7). Attached was a sprawl of later buildings, some of value, like the monumental bottle kilns (Fig. 2-8), others no more than flimsy sheds.As is often the case, the architect‟s first task was to establish what was worth keeping. Designer Vasquez Consuegra retained t he evidence of the site‟s past and recognized the significance of its more recent history as a factory. The historical structure in its different states were respected in this project. Much of the existing complex have been kept, and new buildings have been constructed on part of the site according to the need of new programmes: restoration studios, laboratories, a library and extensive archive, lecture rooms and galleries open to the public. Older buildings were treated as a stimulating body of material for the new project.The contemporary reflects the older but without imitating it. For example,the restoration studios with a lofty roof structure are entirely new - concrete and steel is used, however they are built usingtraditional industrial architecture qualities and harmoniously complement the original complex (fig. 2-8,9). Refurbishment was guided by a concern to protect old fabric, Fig. 2-7 The cloister of the early monastery.13Figure 2-8The bottle kilns.14Fig. 2-9 The newly built restoration studio.15but to add to it in an entirely contemporary way.In the approach of complementary, the historic character is wellmaintained while the boundary between old and new is clearlydefined. Respecting the spatial context, the recreation orrestoration should follow the original idea. Emphasising themateriality of the original structure, new elements should notcompete with the original. Considering historic authenticity,historical structure of different time period should be interpretedwhile imitation or replication is not allowed.Fig. 2-10. Newly built restorationstudios.16Association: Serpentine Sackler Gallery, LondonSerpentine Sackler Gallery in London was originally aGunpowder Store built in 1805. ZahaHadid's new extension tothe Serpentine Gallery features a glazed restaurant with anundulating fabric roof. Built from a glass-fibre textile, the newtensile structure forms a free-flowing white canopy supportedby five tapered steel columns and outlined by a frameless glasswall.The idea was to use a new material - a tensile structure -and to look at domes and a shell structure to achieve a lightweight contemporary project. Describing the contrast between the new and old structures, ZahaHadid said: "We don't look forward by looking backwards. It is necessary sometimes to be able to match and be adjacent to historic buildings. The idea here was to really prove that you can have these two worlds, which are the new and the old, and then the garden and the park together in a seamless way".17Association: Elbe Philharmonic Hall,HamburgThe Elbe Philharmonic Hall is a concert hall under construction in Hamburg, Germany. Herzog & de Meuron has designed a new structure sits on top of an old warehouse building. Like a large glassy wave, the concert hall seems to float above the former red-brick warehouse. The construction work is scheduled to end in October 2016. The whole building will accommodate two concert halls, a 5-star hotel, apartments and a large car park.While historic character is emphasised in the intervention of integration and complementary, in the case of association, traces of the past become aesthetic backdrops for new structures which may be deliberately disruptive but has a beauty of its Figure 2-11 Serpentine Sackler Gallery. Right is the old gunpower store, left is the added part.Fig. 2-12Elbe PhilharmonicHall in construction, 2015.18own. There is a broad range of design possibilities for this kind of approach, in which the new and the old overlap, mediate and confront each other fearlessly. Same as design and construction of a new architecture, the approach of association is the most interesting as well as challenging. To ensure safety of the original building and the possibility of correcting any wrong decisions, the reversibility of the intervention must always berequired.Whether in the form of integration, complementary or association, the principles of authenticity, minimal intervention, recognisability and especially reversibility safeguard the cultural values of historic architecture. By integration and complementary, the identified historic features are more addressed than by association, which brings in new elements as well as new values. It is thus vital to identify all factors and issues cautiously through investigation and explore different options of intervention before decision-making. In successful adaptive reuse, the arts of architecture should be able to enhance both the values of the original structure and the newly built sections.3.Adaptive reuse as a way for sustainable development Belong to the disciplines of conservation and architecture, it is however the intention of neighbourhood revitalization and environmental sustainable development that has finally impelled the popularisation of adaptive reuse in regions like America and West Europe since 1960‟s. This transformation has much to do with the economic, ecological and social evolution of the time.3.1BackgroundAfter the WWII, the change of built environment in many countries accelerated to such an extent that redundancy followed by demolition became commonplace in urban areas.In economic-developed countries like the States, the post-war years witnessed the movement of suburbanisation, with substantial amount of public housing being built in suburbs, leaving the existing central urban housing stock largely vacant. Information Box: Suburbanisation The trend of city dwellers move from city’s core to fringes began generally in the 19th century. The growth of areas on the fringes of cities exploded after World War II. Especially in metropolitan areas, many residents working in urban centre move to liveWhen people moved to the suburbs, churches and other community buildings in the urban centre were left hence doomed to dereliction and demolition. Planning policies of relocating industry and trade out of the inner cities to suburban areas have also resulted in the demolishment of former industrial buildings in urban centre. The improvement in transportation also led to relocation of industries from densely-developed cities towards more sparsely-populated suburban and rural areas.19 Advantages of traditional harbour cities were weakened with the utilisation of container ships which required deeper and more mechanised ports. Manufacturing industries were moved beyond the shores of the States and Europe due to the cheaper costs. More and more cities and towns were confronted with deindustrialisation, leaving empty buildings disused.20in satellite communities, where their own shopping and service districts have been developed. Transportation advances, industrial growth and immigration had major impacts on this suburb growth. Suburbanization has benefits as well as side effects. It intensifies urban decay and segregation. In America, lower income residents concentrated in the inner city while suburban life relates to while privilege.3.2The rise of adaptive reuseFacing demolition and new built in the process of urban and industries transformation, people began to recognise that retention and revitalization of existing buildings were not just a historical-conservationist issue, but was essential in the character and habitable quality of the area involved. Jane Jacobs is the most influential pioneer that launched this kindo of rethinking.On the one hand, residents had increased identification with the historically evolving tissue of their surroundings; on the other, there was a growing awareness of environment and natural resources. The wish of reusing existing building resources encouraged the rise of adaptive reuse. By reusing existing structure within a site, it utilises a less energy than a typical process of demolition and construction. Adaptive reuse is also seen by many as an effective way of reducing urban sprawl and lessoning environmental impact.Citizens‟ action groups, initiatives and other organisations fought for the retention of existing buildings and neighbourhoods posed great influence on the trail of development. Young people who took their own initiatives and engaged in self-help activities to realise housing and other user requirements accelerated the process of conversion and adaptation of existing buildings.21 The transformation of the society regarding values and bottom-up mechanism resulted from this movement was deep and broad.The attention of planners and governments started to shift from urban renewal and expansion to preservation and reuse of existing buildings and districts. In 1967, the Civic Amenities Act in Britain broke new ground by asking local authorities to designate conservation areas and encouraged other countries to introduce similar legislation.22 More restrained and sensitive urban development began to replace large-scale redevelopment Information Box: Jane JacobsFig. 2-13 Mrs. Jane Jacobs to save the West Village holds up documentary evidence at press conference.24The awareness of identity and the fear of changes of local residents were triggered by Jane Jacobs(1916 –2006), an American-Canadian journalist, author, and activist. She played a major role in this process of rethinking. In her influential work The Death and Life of Great American Cities (1961), she observed the ways in which cities functioned and argued that urban renewal did not respect the needs of most residents. “Ordinary buildings, as well as landmarks, needed to be preserved - modernist planning had disregarded the organic qualities of the city…Cities need old buildings…by old buildings I mean not museum-piece old buildings… but also a lot of plain, ordinary, low-value old buildings, including some rundown old buildings.”25She changed the urban planning profession and discredited many accepted planning models that dominated mid-century planning.26schemes which could result in structural change. For instance, in the States, Britain and other European countries, their new national policies which provide incentives for refurbishing old buildings rather than demolishing largely encouraged adaptive reuse of old buildings.233.3Trends of adaptive Reuse in the Late 20th Century In the 1980‟s to 1990‟s, working with existing buildings which were sometimes built in the 1960‟swas major in architectural practice. For instance, a survey revealed that over 70% of the workload of American architects was concerned with reuse of buildings at the end of 1990‟s.27 In Britain, the ratio of national resources allocated in new buildings and maintenance of existing buildings has increased from4:1 in the 1990‟s to half-half in the 2000‟s.28 In Germany, the percentage has also continuously shifted towards working with existing buildings. In 1997, 46.3% of construction work was conducted in existing buildings; whereas in 2007, the measures taken in existing buildings contributed 74% of all residential construction.29 Today it is generally accepted in Western Europe and America that conservation policy, of which find new uses for old buildings is a part of, must be integral with planning policy. Underlying this is the insight that successful conversion and integration of existed buildings and their new uses into the functional fabric of towns and cities can have a positive, stimulating effect on the social and economic life of an area.3.4Transformation of industries and industrialbuildingsSuccessful adaptive reuse can be the catalyst of revitalizing existing urban areas, which is particularly notable in the transformation of industrial heritage in the United States and Europe. Industrial heritage distinguishes itself from other types of heritage as it usually has larger site and space, andrelatively less historic value. Industrial buildings often clusterand form industrial areas; adaptive reuse of such industrial areas hence tend to be large urban project or urban transformation. Industrial heritage is not only about identity, memory and traditions; rather, it belongs to cities, sites, and their transformations. The context of urban change requires to be taken into account in the management of industrial heritage sites, and the balance conservation and development. Economic and social decay had been intensified in Americancities since the 1960‟s.30 Several industrial centres which used to flourish were facing terminal decline. Large parts of the inner areas became poor ghettos for immigrants groups. Waterfront and wholesaling areas were made redundant and isolated by new freight-handling methods. After the oil crisis in the early 1970‟s, those decaying cities started to adapt to such change. For example in Boston the rehabilitation of the nearly abandoned Quincy Market, one of the largest market complex built in the United States in the early 1900s, became a huge success. The added buildings expand the market space for more restaurants, specialty shops, office spaces and active open spaces. Other formerly obsolete buildings in the area were refurbished rather than demolished. In late 1970‟s and early 1980‟s, the American attitudes towards old buildings had completely changed. Many former factories became prime tourist destinations.In Britain, industrial heritage was under threat in the 1970‟s as well. In Liverpool, the rescue of the long-threatened Albert Dock, the finest historic dock complex left, was a boost for this rundown northern port city. The shops there were let while the apartments were sold. Granada Television also carried out an immaculate refurbishment of a former office building as its local base. From being a forgotten place, the Dock has been transformed into one of the Liverpool's most important tourist attractions and a vital component of the city's UNESCO world heritage Maritime Mercantile City.31By the late1980‟s, the economic potential of sound old buildings was unquestionable, and the regeneration value of the reuse projects was also recognised.32In the States and Europe, smokestacks and warehouses which once defined neighbourhoods or even cities have become museums that attract streams of visitors and new housing and office buildings which serve the locals. 33 Similar ventures also succeeded in northern France, where old textile mills around Lille have been turned into housing and shopping complexes.34In most cases, new uses in adapted buildings usually do not relate to the former industrial use despite its industrial design. The new programmesin such buildings are often museums and cultural centres since old factories and warehouses often offer large, open raw spaces that fit for exhibition of contemporary art. On the other hand these museums and cultural centres couldbecome destinations and bring in ancillary uses as a result. Adaptive reuse projects are thus used to maintain neighbourhoods‟ sense of history in hopes of attracting visitors to come not only for the exhibitions, but also to eat, shop, and stay overnight. These projects create foci of activities, sources of employment, retail opportunities, as well as reminding visitors and residents of the past achievements and success.Not every place is able to or wants to be a cultural mecca; apart from cultural project, industrial heritage can opt for other types of adaptive reuse such as residential, commercial and mixed-useFig. 2-14. Albert Docks and LiverpoolLandmarks on the River Mersey.36hiFig. 2-15 Duisburg Landscape Park.By Michael Latz.。

TE Connectivity 混合电动汽车解决方案产品概述说明书

Hybrid & Electric Mobility SolutionsPUT THE POWER ON THE ROADTE Connectivity (TE) provides a complete line of connectors, relays, harnesses, contactors and disconnects to safely connect and protect the flow of data and power around your hybrid or electric vehicle.TE‘s automotive products have been proven in light and heavy-duty vehicles and our technologies leverage decades of experience with high-voltage generation, transmission and distribution. So you can depend on them to be safe and reliable in your application.capabilities.Our technologies leverage decades of experience with high-voltage generation, transmission and distribution and you can depend on them to be safe and reliable in your application.Mobility simplified. One charge at a time. TE is helping enable electric mobility by creating safe, high-quality components for every part of the charging station – and making them affordable. Our experience with high-voltage energy distribution and Smart-Grid technology gives us insight into the needs of this important market segment. More than a complete charging solution.A smart one. Smart charging solutions enable customers to meter their EV’s electricity consumption, and communicate data via innovative smart charging cords and inlets. You supply the shell, we’ll supply everything else. TE has everything it takes to create your charging solution, except the box it goes in. From cables to contactors, meters to card readers, screens to sockets, we’ve already solved how it all goes together.CHARGING SOLUTIONSAMP+ line of cables, connectors, harnesses and terminals safely and reliably channel high- and low-voltage power in and around the battery and vehicle, to help you put the power to the road.Completing the connections that power it all. More than 50 years of experience with high-voltage electricity separates us from automotive engineering companies in the hybrid and EV industry.We’re using that knowledge to help create smarter, better, easier ways to connect the grid to drivers – and give them the mobility they need. Before everyone can embrace driving hybrid and electric vehicles, we need a safe, reliable way to get the power from the grid to the chargers, and into the batteries.TE’s broad array of energy and industrial technologies have seen decades of real-world use connecting and protecting the flow of power around the world. So you can depend on them to be safe and reliable in your application, too. INFRASTRUCTURE SOLUTIONSCatalog 1654294-4 Publishxed xx-2017Catalog 1654294-4 Publishxed xx-2017Catalog 1654294-4Publishxed xx-2017At TE Connectivity, we support your RoHS requirements. We’ve assessed more than 1.5 million end items/components for RoHS compliance, and issued new part numbers where any change was required to eliminate the restricted materials. Part numbers in this catalog are identified as:RoHS CompliantPart numbers in this catalog are RoHS Compliant, unless marked otherwise. These products comply with European Union Directive 2002/95/EC as amended 1 January 2006 that restricts the use of lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE in certain electrical and electronic products sold into the EU as of 1 July 2006.Note: For purposes of this Catalog, included within the definition of RoHS Compliant are products that are clearly “Out of Scope” of the RoHS Directive such as hand tools and other non-electrical accessories. Non-RoHS CompliantThese part numbers are identified with a “t” symbol. These products do not comply with the material restrictions of the European Union Directive 2002/95/EC.5 of6 CompliantA “l” symbol identifies these part numbers. These products do not fully comply with the European Union Directive 2002/95/EC because they contain lead in solderable interfaces (they do not contain any of the other five restricted substances above allowable limits). However, these products may be suitable for use in RoHS applications where there is an application-based exception for lead in solders, such as the server, storage, or networking infrastructure exemption. Note: Information regarding RoHS compliance is provided based on reasonable inquiry of our suppliers and represents our current actual knowledge based on the information provided by our suppliers. This information is subject to change. For latest compliance status, refer to our website referenced below. So whatever your questions when it comes to RoHS, we’ve got the answers at / customersupport/rohssupportcenter/Catalog 1654294-4Publishxed xx-2017Remark: Starting from 0.03 mm2 (AWG 32) a wire can be crimped.Most of the wire size ranges are mentioned in mm 2, as well as the insulation diameters which are in many cases only in mm’s We therefore included the con-version tables on page X and page XI. Please note that wire and insulation sizes are for guidance only. Consult the customer drawing for precise detail.FLK and FLR stand for German DIN (72551) abbreviations. FLK means: In German: • Fahrzeug-Leitung Kunststoff In English: • Vehicle Cable Plastic FLR means: In German: • Fahrzeug-Leitung reduziert In English:• Thin Walled Cable (reduced insulation thickness)P a g eP o w e r t r a i n S y s t e m sS a f e t y &S e c u r i t y S y s t e m sC o n v e n i e n c eD r i v e r I n f o r m a t i o nB o d y &C h a s s i s S y s t e msCatalog 1654294-4Publishxed xx-2017P a g eP o w e r t r a i n S y s t e m sS a f e t y &S e c u r i t y S y s t e m sC o n v e n i e n c eD r i v e r I n f o r m a t i o nB o d y &C h a s s i s S y s t e m sCatalog 1654294-4Publishxed xx-2017P a g eP o w e r t r a i n S y s t e m sS a f e t y &S e c u r i t y S y s t e m sC o n v e n i e n c eD r i v e r I n f o r m a t i o nB o d y &C h a s s i s S y s t e msCatalog 1654294-4Published 04-201744AMP+ IPTConnector for powertrain applications in high vibrationenvironment, up to 300A (depending on wire crosssection) at 105°. Used e.g. to connect inverter toe-machine and charging applications.IP Rating: IP6k9kHVIL:noCPA:noFire Classification:HBVibration Level:4Application Specification: 114-94133Product Specification: 108-94293Interface Drawing:114-94132-1AMP IPT 1pxiVersion(Cable Dimension)Coding Order Information25 / 35 / 50 mm²(acc. LV216-2)releasedATo be Orderedsee drawing!BCDEF16 mm²in planningDrawing 114-94131-1 *IP Rating: IP6k9kHVIL:noCPA:noFire Classification:HBVibration Level:4Application Specification: 114-94133Product Specification: 108-94293Interface Drawing:114-94132-2AMP IPT 2pxiVersion(Cable Dimension)Coding Order Information25 / 35 / 50 mm²released ATo be Orderedsee drawing!16 mm²in planningDrawing 114-94131-2 *IP Rating: IP6k9kHVIL:noCPA:NoFire Classification:HBVibration Level:4Application Specification: 114-94133Product Specification: 108-94293Interface Drawing:114-94132-3AMP IPT 3pxiVersion(Cable Dimension)Coding Order Information25 / 35 / 50 mm²released ATo be Orderedsee drawing!16 mm²in planningDrawing 114-94131-3 *white papers and other technical information. To download our literature visit/automotiveliterature.htmlor document questions. To contact a PIC representative, visit /support-centerCatalog 1654294-4Publishxed 04-2017DISCLAIMERWhile TE Connectivity (TE) has made every reasonable effort to ensure the accuracy of the information in this catalog, TE does not guarantee that it is error-free, nor does TE make any other representation, warranty or guarantee that the informati-on is accurate, correct, reliable or current. TE reserves the right to make any adjustments to the information contained herein at any time without notice.TE expressly disclaims all implied warranties regarding the information contained herein, including, but not limited to, any implied warranties of merchantability or fitness for a particular purpose. The dimensions in this catalog are for reference pur-poses only and are subject to change without notice. Specifications are subject to change without notice. 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托福听力tpo68 lecture1、2、3 原文+题目+答案+译文

托福听力tpo68 lecture1、2、3 原文+题目+答案+译文Lecture1 (2)原文 (2)题目 (4)答案 (6)译文 (6)Lecture2 (7)原文 (8)题目 (10)答案 (12)译文 (12)Lecture3 (14)原文 (14)题目 (17)答案 (19)译文 (19)Lecture1原文Professor: OK, let’s look at two specific ancient cultures of the arctic, both of which lived on the far northern edge of the continent, the Dorset and the Thule. The Dorset culture began around eight hundred BC and ranged to cross most of arctic Canada. The Thule, well, they lived in the same area, but about twelve hundred years later. Both groups left some beautiful art behind, really are best evidence that these folks even existed. And although these two cultures lived in the same region, each group approached their art in very different ways.Alright, so the Dorset culture. Archaeologists have unearthed hundreds of Dorset sculptures mostly carve from ivory or bone and sometimes stone. They were mostly small sculptures of animal or human figures. And our best guess is that they were probably used mainly for religious purposes. The main subject of Dorset animal sculptures is the polar bear. Some of these polar bears are represented in naturalistic or realistic ways, but usually, their abstracted or stylized that is to say less realistic. Here is a typical polar bear sculpture. It's carved from ivory, we call these artifacts flying or floating polar bears, because, because they look like the polar bears doing just that flying or floating. Notice the distinctive markings, they seem to mark out the skeleton or joints of the bear.While polar bears were favorite subject, the Dorset created sculptures of other animals too, like seals and caribou which were represented in a more realistic fashion. We speculate that if the Dorset feared or respected a particular animal, they were more likely to present it in a stylized way, like with the polar bear, which, of course, is a large dangerous predator, maybe, it was a way of dealing with their fear. We also have Dorset’s sculptures whose meaning is more allusive. I'm talking about horns with many human faces carved into them. What's remarkable about these sculptures is the variety of facial types in expressions that appear on the single horn. If only the people represented on these artifacts could answer our questions, it tells us whetherthey are ancestors or residents of villager or what.Okay, let's switch to Thule art, which differs from Dorset art in, in some important ways. Interestingly, Thule artwork wasn't generally influenced by the earlier Dorset culture. It seems it would’ve grown out of a separate tradition that originated in Alaska. Thule artwork was most likely used to decorate common objects such as tools with attractive designs, we can't be entirely sure about this. However, we've tried to interpret the symbolic designs into the art. But of course, it's impossible to confirm the accuracy of such interpretations. What we do know is that the Thule people made extensive use of engravings, they drove the small holes and carve lines into various materials. These engravings, engraved patterns, rather, are found on the diverse group of artifacts, things ranging from weapons to jewelry to cones and boxes. Here's some examples. It's hard to see, but most of these objects do have engravings on them. Thule art was more of a graphic art. Uh, more like drawing. Many of their designs are geometric and abstract. Others containing engravings of human and animal figures.For instance, the long skinny object, among left, has a face at the top. We’ve also found the tool handle with hunting and camp scenes carved into it. As far as Thule’s sculpture goes, there is only a few small objects in wooden dowels like the one in the bottom right-hand corner. These have either no facial features or very rudimentary ones, less detailed, less individualized than the faces of Dorset’s sculpture.One scholar has argued that this difference resulted from the nature of Thule’s society which was built around group hunting expeditions on the ocean. This hunting approach required a great deal of cooperation which may have led to a kind of an overall uniformity in their art. And emphasis on commonality rather than individuality, which probably explains why there’re human figures like the faces or had standardized faces that all look similar. The most famous of the few Thule sculptures are the ones of birds in creatures that are part bird and part woman. While the sculpture is probably had some symbolic purpose, patterns of holes were drilled into them too. So, in general compared with artwork of the Dorset, Thule artprobably had a more decorative or utilitarian function.题目1.What is the main purpose of the lecture?A. To examine the extent to which Thule and Dorset art influenced the artwork of other arctic culturesB. To examine how Thule and Dorset designs changed over timeC. To compare and contrast artwork from two ancient arctic culturesD. To discuss how the natural world is shown in the artwork of two ancient arctic cultures2.What does the professor imply about “flying”or “floating”polar-bear sculptures?[Click on 2 answers.]A. They may have helped the Dorset people cope with their fear of a dangerous animal.B. Art historians consider them to be of little religious importance to the Dorset people.C. The Dorset people created them to demonstrate respect for polar bears.D. They were designed to take advantage of the natural shape of the ivory.3.According to the professor, what can be inferred about Dorset society based on its artwork?A. It placed more emphasis on religious beliefs than Thule society did.B. It relied on hunting large animals to a greater extent than Thule society did.C. It placed an emphasis on the production of jewelry.D. It was structured to support long ocean expeditions.4.According to the professor, what appears to be the main reason that the Thule engraved holes and lines into their artifacts?A. To honor their Alaskan ancestorsB. To illustrate the layout of their campgroundsC. To add realism to their sculpturesD. To add decoration to their sculptures5.Why does the professor mention Thule group-hunting expeditions?A. To explain why the Thule had plenty of time to produce detailed artworkB. To draw a connection between cooperation in finding food and uniformity in artC. To compare Thule hunting practices with Dorset hunting practicesD. To suggest that the majority of Thule sculptures were probably lost at sea6.Why does the professor saythis:If only the people represented on these artifacts could answer our questionsA. To suggest that the students interview descendants of Dorset peopleB. To propose a topic that the students could write aboutC. To ask students who they think the faces representD. To indicate that there is still a lot of missing information答案C AC AD B D译文教授:好的，让我们来看一下北极的两种特定的古代文化，它们都生活在大陆的最北端，Dorset文化和Thule文化。

学术英语写作-东南大学中国大学mooc课后章节答案期末考试题库2023年

学术英语写作_东南大学中国大学mooc课后章节答案期末考试题库2023年1.Sequence markersin English are a certain group of items that link sentencestogether into a larger unit of _______.参考答案:discourse2.When the author uses “Methodology” as the title of this section, he/she needsto provide the_______for how the experiment was designed and conducted for the current study.参考答案:rationales3.“Shopping malls are wonderful places.” is a weak thesis statemen t in that itrestates conventional wisdom.参考答案:错误4.One way is to examine one thing thoroughly and then examine the other. Thismethod is called _____ comparison or contrast.参考答案:block5. A strong thesis statement makes a claim that offers some point about thesignificance ofour evidence that requires further argumentation.参考答案:正确6.Strictly speaking, the purpose of _______ is to show similarities while contrastis used to show differences.参考答案:comparison7.In the elements of the Method Section, ______ refer to the precautions taken tomake sure that the data are valid.参考答案:Restrictions8.Paraphrasing is to explain the original ideas of a passage, chapter, article orbook in fewer words.参考答案:错误9.To avoid plagiarism and conform to academic ethics, you need to providereference to every citation and check for plagiarism before submitting your paper.参考答案:正确10.Which of the following tenses could be used to discuss previously publishedworks which is generally considered to be established knowledge?参考答案:The present simple11.Which of the following tenses could be used when the year of publication isstated within the main sentence.参考答案:The past tense12.Which of the following reporting verbs could be categorized as strong?参考答案:reject13.Reporting verbs can indicate either参考答案:All of the options.14.What is included in a complex model of literature review but NOT included ina simple one?参考答案:Research question15.You can choose any information or data from the graphwhen you describeagraph.参考答案:错误16.Redundancy, raising a totally new point, understatement, anticlimax are thetypical issues in structuring the Conclusion.参考答案:错误17.Unlike the Abstract and Introduction，the Conclusions section does providebackground details.参考答案:错误18. 1. The register of the following discourse is____.I, James Bond, take you, JudithKroll, to be my wife, to have and to hold from this day forward, for better, for worse, for richer, for poorer, in sickness and in health, to love and to cherish, till death us do part, according to God's holy law, in the presence of God Imake thisvow.参考答案:static19.What should you do when you write a literature review?参考答案:Include a critical analysis of various opinions from credible sources.20.To end the Discussion section which also has a Conclusion, the author mayadmit what she/he has not been able to do and as a consequence cannotprovide conclusions on.参考答案:正确21.If the authors are to announce the results of their study, they can just statethe results without saying “we think that…”参考答案:正确22.You can use “he or she” to avoid gender discrimination every time when youmean “everyone”.参考答案:错误23.When writing an academic paper, you should nominalize as many words aspossible.参考答案:错误24.Beginning the Discussion section an author would possibly refer back topapers he/she cited in the Review of the Literature.参考答案:正确25.“The U.S. constitution” is not a good title for an essay, because it is toogeneral.参考答案:正确26.“What implications are revealed in my results?” is a question to considerafter drafting the Discussion section.参考答案:错误27.The process paragraphs are usually developed step by step in a chronologicalor logical sequence.参考答案:正确28.The Results Section can only be presented both in diagrams or graphs.参考答案:错误29.The Method Section can be called Materials and Methods in naturalsciences.参考答案:正确30.The Method Section is considered the most important section becauseitappears in the middle of a research paper.参考答案:错误31.Nominalization is the process of converting simple nouns within a sentenceto complex nouns.参考答案:错误32.If you can discuss a cause without having to discuss any other causes thenvery likely it is an indirect cause.参考答案:错误33.Oversimplification should be avoided because many problems have complexcauses and complex effects.参考答案:正确34.First personal pronouns can never be used in academic paper.参考答案:错误35. A weak thesis statement either makes no claim or makes a claim that doesnot need proving.参考答案:正确36.One of the key elements of the Conclusion section is a final judgment on theimportance and significance of the findings in terms of their implications and impact, along with possible applications to other areas.参考答案:正确37.Effects are the consequences of an event and they respond to the question“Why did that event happen?”参考答案:错误。

板式换热器外文文献(英文)

DESIGN OF HEAT EXCHANGER FOR HEAT RECOVERY IN CHP SYSTEMSABSTRACTThe objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect different factors of the design. Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Energy Engineering Laboratory of the Mechanical Engineering Department of the University of Louisiana at Lafayette and the Louisiana Industrial Assessment Center has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated with a heat exchanger to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller which cannot be altered.INTRODUCTIONCombined Heat and Power (CHP), also known as cogeneration, is a way to generate power and heat simultaneously and use the heat generated in the process for various purposes. While the cogenerated power in mechanical or electrical energy can be either totally consumed in an industrial plant or exported to a utility grid, the recovered heat obtained from the thermal energy in exhaust streams of power generating equipment is used to operate equipment such as absorption chillers, desiccant dehumidifiers, or heat recovery equipment for producing steam or hot water or for space and/or process cooling, heating, or controlling humidity. Based on the equipment used, CHP is also known by other acronyms such as CHPB (Cooling Heating and Power for Buildings), CCHP (Combined Cooling Heating and Power), BCHP (Building Cooling Heating and Power) and IES (Integrated Energy Systems). CHP systems are much more efficient than producing electric and thermal power separately. According to the Commercial Buildings Energy Consumption Survey, 1995 [14], there were 4.6 million commercial buildings in the United States. These buildings consumed 5.3 quads of energy, about half of which was in the form of electricity. Analysis of survey data shows that CHP meets only 3.8% of the total energy needs of the commercial sector. Despite the growing energy needs, the average efficiency of power generation has remained 33% since 1960 and the average overall efficiency of generating heat and electricity using conventional methods is around 47%. And with the increase in prices in both electricity and natural gas, the need for setting up more CHP plants remains a pressing issue. CHP is known to reduce fuel costs by about 27% [15] CO released into the atmosphere. The objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect differentfactors of the design. Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined.The Mechanical Engineering Department and the Industrial Assessment Center at the University of Louisiana Lafayette has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller which cannot be altered.Integrating equipment to form a CHP system generally does not always present the best solution. In our case study, the absorption chiller is not able to utilize all of the waste heat from the turbine exhaust. This is because the capacity of the chiller is too small as compared to the turbine capacity. However, the need for extra space conditioning in the buildings considered remains an issue which can be resolved through the use of this CHP system. BACKGROUND LITERATUREThe decision of setting up a CHP system involves a huge investment. Before plunging into one, any industry, commercial building or facility owner weighs it against the option of conventional generation. A dynamic stochastic model has been developed that compares the decision of an irreversible investment in a cogeneration system with that of investing in a conventional heat generation system such as steam boiler combined with the option of purchasing all the electricity from the grid [21]. This model is applied theoretically based on exempts. Keeping in mind factors such as rising emissions, and the availability and security of electricity supply, the benefits of a combined heat and power system are many.CHP systems demand that the performance of the system be well tested. The effects of various parameters such as the ambient temperature, inlet turbine temperature, compressor pressure ratio and gas turbine combustion efficiency are investigated on the performance of the CHP system and determines of each of these parameters [1]. Five major areas where CHP systems can be optimized in order to maximize profits have been identified as optimization of heat to power ratio, equipment selection, economic dispatch, intelligent performance monitoring and maintenance optimization [6].Many commercial buildings such as universities and hospitals have installed CHP systems for meeting their growing energy needs. Before the University of Dundee installed a 3 MW CHP system, first the objectives for setting up a cogeneration system in the university were laid and then accordingly the equipment was selected. Considerations for compatibility of the new CHP setup with the existing district heating plant were taken care by some alterations in pipe work so that neither system could impose any operational constraints on the other [5]. Louisiana State University installed a CHP system by contracting it to Sempra EnergyServices to meet the increase in chilled water and steam demands. The new cogeneration system was linked with the existing central power plant to supplement chilled water and steam supply. This project saves the university $ 4.7 million each year in energy costs alone and 2,200 emissions are equivalent to 530 annual vehicular emissions.Another example of a commercial CHP set-up is the Mississippi Baptist Medical Center. First the energy requirement of the hospital was assessed and the potential savings that a CHP system would generate [10]. CHP applications are not limited to the industrial and commercial sector alone. CHP systems on a micro-scale have been studied for use in residential applications. The cost of UK residential energy demand is calculated and a study is performed that compares the operating cost for the following three micro CHP technologies: Sterling engine, gas engine, and solid oxide fuel cell (SOFC) for use in homes [9].The search for different types of fuel cells in residential homes finds that a dominant cost effective design of fuel cell use in micro – CHP exists that is quickly emerging [3]. However fuel cells face competition from alternate energy products that are already in the market. Use of alternate energy such as biomass combined with natural gas has been tested for CHP applications where biomass is used as an external combustor by providing heat to partially reform the natural gas feed [16]. A similar study was preformed where solid municipal waste is integrated with natural gas fired combustion cycle for use in a waste-to-energy system which is coupled with a heat recovery steam generator that drives a steam turbine [4]. SYSTEM DESIGN CONSIDERATIONSIntegration of a CHP system is generally at two levels: the system level and the component level. Certain trade-offs between the component level metrics and system level metrics are required to achieve optimal integrated cooling, heating and power performance [18]. All CHP systems comprise mainly of three components, a power generating equipment or a turbine, a heat recovery unit and a cooling device such as an absorption chiller.There are various parameters that need to be considered at the design stage of a CHP project. For instance, the chiller efficiency together with the plant size and the electric consumption of cooling towers and condenser water pumps are analyzed to achieve the overall system design [20]. Absorption chillers work great with micro turbines. A good example is the Rolex Reality building in New York, where a 150 kW unit is hooked up with an absorption chiller that provides chilled water. An advantage of absorption chillers is that they don’t require any permits or emission treatment [2]Exhaust gas at 800°F comes out of the turbine at a flow rate of 48,880 lbs/h [7]. One important constraint during the design of the CHP system was to control the final temperature of this exhaust gas. This meant utilizing as much heat as required from the exhaust gas and subsequently bringing down the exit temperature. After running different iterations on temperature calculations, it was decided to divert 35% of the exhaust air to the heat exchanger whilethe remaining 65% is directed to go up the stack. This is achieved by using a diverter damper. In addition, diverting 35% of the gas relieves the problem of back pressure build-up at the end of the turbine.A diverter valve can also used at the inlet side of the heat exchanger which would direct the exhaust gas either to the heat exchanger or out of the bypass stack. This takes care of variable loads requirement. Inside the heat exchanger, exhaust gas enter the shell side and heats up water running in the tubes which then goes to the absorption chiller. These chillers run on either steam or hot water.The absorption chiller donated to the University runs on hot water and supplies chilled water. A continuous water circuit is made to run through the chiller to take away heat from the heat input source and also from the chilled water. The chilled water from the absorption chiller is then transferred to the existing University chilling system unit or for another use.Thermally Activated DevicesThermally activated technologies (TATs) are devices that transform heat energy for useful purposed such as heating, cooling, humidity control etc. The commonly used TATs in CHP systems are absorption chillers and desiccant dehumidifiers. Absorption chiller is a highly efficient technology that uses less energy than conventional chilling equipment, and also cools buildings without the use of ozone-depleting chlorofluorocarbons (CFCs). These chillers can be powered by natural gas, steam, or waste heat.Desiccant dehumidifiers are used in space conditioning by removing humidity. By dehumidifying the air, the chilling load on the AC equipment is reduced and the atmosphere becomes much more comfortable. Hot air coming from an air-to-air heat exchanger removes water from the desiccant wheel thereby regenerating it for further dehumidification. This makes them useful in CHP systems as they utilize the waste heat.An absorption chiller is mechanical equipment that provides cooling to buildings through chilled water. The main underlying principle behind the working of an absorption chiller is that it uses heat energy as input, instead of mechanical energy.Though the idea of using heat energy to obtain chilled water seems to be highly paradoxical, the absorption chiller is a highly efficient technology and cost effective in facilities which have significant heating loads. Moreover, unlike electrical chillers, absorption chillers cool buildings without using ozone-depleting chlorofluorocarbons (CFCs). These chillers can be powered by natural gas, steam or waste heat.Absorption chiller systems are classified in the following two ways:1. By the number of generators.i) Single effect chiller –this type of chiller, as the name suggests, uses one generator and the heat released during the absorption of the refrigerant back into the solution is rejected to the environment.ii) Double effect chiller –this chiller uses two generators paired with a single condenser, evaporator and absorber. Some of the heat released during the absorption process is used to generate more refrigerant vapor thereby increasing the chiller’s efficiency as more vapor is generated per unit heat or fuel input. A double effect chiller requires a higher temperature heat input to operate and therefore its use in CHP systems is limited by the type of electrical generation equipment it can be used with.iii) Triple effect chiller –this has three generators and even higher efficiency than a double effect chiller. As they require even higher heat input temperatures, the material choice and the absorbent/refrigerant combination is limited.2. By type of input:i) Indirect-fired absorption chillers –they use steam, hot water, or hot gases from a boiler, turbine, engine generator or fuel cell as a primary power input. Indirect-fired absorption chillers fit well into the CHP schemes where they increase the efficiency by utilizing the otherwise waste heat and producing chilled water from it.ii) Direct-fired absorption chillers –they contain burners which use fuel such as natural gas. Heat rejected from these chillers is used to provide hot water or dehumidify air by regenerating the desiccant wheel.An absorption cycle is a process which uses two fluids and some heat input to produce the refrigeration effect as compared to electrical input in a vapor compression cycle in the more familiar electrical chiller. Although both the absorption cycle and the vapor compression cycle accomplish heat removal by the evaporation of a refrigerant at a low pressure and the rejection of heat by the condensation of refrigerant at a higher pressure, the method of creating the pressure difference and circulating the refrigerant remains the primary difference between the two. The vapor compression cycle uses a mechanical compressor that creates the pressure difference necessary to circulate the refrigerant, while the same is achieved by using a secondary fluid or an absorbent in the absorption cycle [11].The primary working fluids ammonia and water in the vapor compression cycle with ammonia acting as the refrigerant and water as the absorbent are replaced by lithium bromide (LiBr) as the absorbent and water (H2O) as the refrigerant in the absorption cycle. The process occurs in two shells - the upper shell consisting of the generator and the condenser and the lower shell consisting of the evaporator and the absorber.Heat is supplied to the LiBr/H2O solution through the generator causing the refrigerant (water) to be boiled out of the solution, as in a distillation process. The resulting water vapor passes into the condenser where it is condensed back into the liquid state using a condensing medium. The water then enters the evaporator where actual cooling takes place as water is passes over tubes containing the fluid to be cooled.Heat ExchangerA very low pressure is maintained in the absorber-evaporator shell, causing the water to boil at a very low temperature. This results in water absorbing heat from the medium to be cooled and thereby lowering its temperature. The heated low pressure vapor then returns to the absorber where it mixes with the LiBr/H2O solution low in water content. Due to the solution’s low water content, vapor gets easily absorbed resulting in a weaker LiBr/H2O solution. This weak solution is pumped back to the generator where the process repeats itself.The heat recovery steam generator (HRSG) is primarily a boiler which generates steam from the waste heat of a turbine to drive a steam turbine. The heat recovery boiler design for cogeneration process applications covers many parameters. The boiler could be designed as a fire-tube, water tube or combination type. Further for each of these parameters, there is a variety of tube sizes and fin configurations. For a given boiler, a simplified method that determines the boiler performance has been developed [8].The shell and tube heat exchanger is the most common and widely used heat exchanger in different industrial applications [13]. It is compared to a classic instrument in a concert playing all the important nodes in different complex system set-ups and can be improved by using helical baffles. There are other ways to augment the heat transfer in a shell and tube exchanger such as through the use of wall-radiation [25].The design of a shell and tube heat exchanger fora combined heat and power system basically involves determining its size or geometry by predicting the overall heat transfer coefficient (U). The process of obtaining the heat transfer coefficient values is obtained from literature by correlating results from previous findings in the determination of heat exchanger designs.This involves listing assumptions at the beginning of the procedure, obtaining fluid properties, calculation of Reynolds number and the flow area to obtain the shell and tube sizes. Once U is calculated, the heat balances are calculated. This study also compares the theoretical U values with the actual experimental ones to prove the theoretical assumptions and to obtain the optimum design model [18].A mathematical simulation for the transient heat exchange of a shell and tube heat exchanger based on energy conservation and mass balance can be used to measure the performance. The design of the heat exchanger is optimized with the objective function being the total entropy generation rate considering the heat transfer and the flow resistance [20].Once a heat exchanger is designed, a total cost equation for the heat exchanger operation is deduced. Based on this, a program is developed for the optimal selection of shell-tube heat exchanger [24].The heat exchanger to be used in the CHP system in the end needs to be tested for its performance. A heat recovery module f orcogeneration is tested before use for CHP application through a microprocessor based control system to present the system design and performance data [19].The basis of a CHP system lies in efficiently capturing thermal energy and using it effectively. Generally in CHP systems, the exhaust gas from the prime mover is ducted to a heat exchanger to recover the thermal energy in the gas. The commonly used heat recovery systems are heat exchangers and Heat Recovery Steam Generators depending on whether hot water or steam is required.The heat exchanger is typically an air-to-water kind where the exhaust gas flows over some form of tube and fin heat exchange surface and the heat from the exhaust gas is transferred to make hot water. Sometimes, a diverter or a flapper damper is used to maintain a specific design temperature of the hot water or steam generation rate by regulating the exhaust flow through the heat exchanger.The HRSG is essentially a boiler that captures the heat from the exhaust of a prime mover such as a combustion turbine, gas or diesel engine to make steam. Water is pumped and circulated through the tubes which are heated by exhaust gases at temperatures ranging from 800°F to 1200°F. The water can then be held under high pressure to temperatures of 370°F or higher to produce high pressure steam [21].The Delaware method is a rating method regarded as the most suitable open-literature available for evaluating shell side performance and involves the calculation of the overall heat transfer coefficient and the pressure drops on both the shell and tube side for single-phase fluids [12]. This method can be used only when the flow rates, inlet and outlet temperatures, pressures and other physical properties of both the fluids and a minimum set of geometrical properties of the shell and tube are known. Emission ControlEmission control technologies are used in the CHP systems to remove SO2 (sulphur dioxide), SO3 (sulphur trioxide) NOx (nitrous oxide) and other particulate matter present in the exhaust of a prime mover. Some common emission control technologies are:1、Diesel Oxidation Catalyst (DOC) –They are know to reduce emissions of carbon monoxide by 70 percent, hydrocarbons by 60 percent, and particulate matter by 25 percent (Emissions Control : CHP Technologies Gulf Coast CHP 2007) when used with the ultra-low sulfur diesel (ULSD) fuel. Reductions are also significant with the use of regular diesel fuel.2、Diesel Particulate Filter (DPF) - DPF can reduce emissions of carbon monoxide, hydrocarbons, and particulate matter by approximately 90 to 95 percent (Emissions Control : CHP Technologies Gulf Coast CHP 2007). However, DPF are used only in conjunction with ultra-low sulfur diesel (ULSD) fuel.3、Exhaust Gas Recirculation (EGR) – They have a great potential for reducing NOx emissions.4、Selective Catalytic Reduction (SCR) –SCR cuts down high levels of NOx by reducing NOx to nitrogen (N2) and oxygen (O2).5、NOx absorbers –catalysts are used which adsorb NOx in the exhaust gas and dissociates it to nitrogen.CONCLUSIONSThe various components needed in a CHP system have been presented. Important parameters such as the mass flow rates of the exhaust gas and water can then be defined. The CHP system has been integrated by the use of a heat recovery unit, the design of which has been discussed. A shell and tube configuration is commonly selected based on literature survey. The pressure drops at both the shell and the tube side can be calculated after the exchanger has been sized.Integrating equipment to form a CHP system generally does not always present the best solution. In our case study, the absorption chiller is not able to utilize all of the waste heat from the turbine exhaust. Approximately 65% goes is left to go out the stack. This is because the capacity of the chiller is too small as compared to the turbine capacity. However, the need for extra space conditioning in the buildings considered remains an issue which can be resolved through the use of this CHP system.The heat exchanger designed can either be constructed following the TEMA standards or it can be built and purchased from an industrial facility. The design that is used is based on the methodology of the Bell-Delaware method and the approach is purely theoretical, so the sizing may be slightly different in industrial design. Also the manufacturing feasibility needs to be checked.After the heat exchanger is constructed, the CHP equipment can be hooked together. Again since the available equipment is integrated to work as a system, the efficiency of the CHP system needs to be calculated. Some kind of co ntrol module needs to be developed that can monitor the performance of the entire system. Finally, the cost of running the set-up needs to be determined along with the air-conditioning requirements.。

叶酸抑制同型半胱氨酸诱导的人肾脏系膜细胞增殖_曹露_娄晓盈_牟娜娜_张泉_谭红梅

网络出版时间：2013-04-10 09:23网络出版地址：/kcms/detail/51.1705.R.20130410.0923.002.html叶酸抑制同型半胱氨酸诱导的人肾脏系膜细胞增殖曹露，娄晓盈，牟娜娜，张泉，谭红梅中山大学中山医学院病理生理教研室，广东广州510080△[基金项目] 国家自然科学基金项目（NO.30600250），广东省自然科学基金项目（NO.10151008901000146）及高校基本科研业务费中山大学青年教师培育项目（NO.10ykpy33）资助。

【摘要】目的观察叶酸对同型半胱氨酸（homocysteine, Hcy）诱导的人肾脏系膜细胞增殖作用的影响及其可能机制。

方法人肾脏系膜细胞采用含5%胎牛血清的RPMI1640培养，采用不同浓度Hcy（200、400、600、800、1000μmol/L）处理细胞，MMT法观察Hcy对人肾脏系膜细胞增殖的影响。

选取理想的Hcy浓度，加入不同浓度叶酸（50、100、200、400μmol/L）处理细胞，观察叶酸对细胞增殖的干预作用。

相同方法处理细胞后提取总蛋白，western blot检测转化生长因子-β（transforming growth factor-β, TGF-β）和细胞外调节蛋白激酶（extracellular regulatedprotein kinases, ERK）表达。

结果Hcy能诱导人肾脏系膜细胞的增殖，促进TGF-β和ERK蛋白表达，呈现剂量依赖性。

叶酸干预后能抑制Hcy诱导的细胞增殖，下调TGF-β和ERK蛋白表达。

结论叶酸能抑制Hcy诱导的人肾脏系膜细胞增殖，可能与抑制TGF-β和ERK蛋白表达有关。

【关键词】同型半胱氨酸；叶酸；转化生长因子-β；细胞外调节蛋白激酶；人肾脏系膜细胞Folic acid attenuated homocysteine-induced proliferation of human renal mesangial cellsLu Cao, Xiaoying Lou, Nana Mou, Quan Zhang, Hongmei TanDepartment of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen UniversityGuangzhou, 510080, China.Correspondencing author: Hongmei Tan, MD, PhD, Associate professor, Department ofPathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 ZhongshanRoad II, Guangzhou 510080, China, Tel: (8620) 87330028, Fax: (8620) 87330026,E-mail: tanhm@【Abstract】Objective This study aimed to investigate the effect of folic acid (FA) onhomocysteine (Hcy)-induced proliferation of human renal mesangial cells (HMCs) andpossible signaling mechanisms. Methods HMCs were cultured in RPMI1640 mediumsupplemented with 5% fetal bovine serum. HMCs were treated with PBS, Hcy (200, 400,600, 800 and 1000μmol/L) or Hcy (400μmol/L) plus folic acid (50、100、200、400μmol/L)for 24 hours. Cells viability were assessed by using Methylthiazolyldiphenyl-tetrazoliumbromide (MMT) assay and the alterations of transforming growth factor-β (TGF-β) and extracellular regulated protein kinases (ERK) were detected by western blot analysis. Results Hcy significantly stimulated the proliferation of HMCs in a dose dependent manner. However, Hcy-induced proliferation of HMCs was attenuated by additional supplement of FA. Protein levels of TGF-β and ERK were increased in the presence of Hcy, which was reversed by additional supplement of FA. Conclusion FA attenuated Hcy-induced proliferation of HMCs, which was associated with decreased expression of TGF-β and ERK protein.[Key words] Homocysteine; Folic acid; Transforming growth factor-β; Extracellular regulated protein kinases; Human renal mesangial cells同型半胱氨酸（homocysteine, Hcy）是蛋氨酸转甲基过程中的一个产物，高同型半胱氨酸血症（hyperhomocysteinemia, HHcy）是心血管疾病的独立危险因素[1]。

Comment on Electronic structure and orbital ordering of SrRu$_{1-x}$Ti$_x$O$_3$ GGA+U inves

$Comment on Electronic structure and orbital ordering of SrRu$_{1-x}$Ti$_x$O$_3$ GGA+U inves$

a r X i v :0807.2904v 1 [c o n d -m a t .s t r -e l ] 18 J u l 2008Comment on ”Electronic structure and orbital ordering of SrRu 1−x Ti x O 3:GGA+Uinvestigations”Kalobaran Maiti ∗Department of Condensed Matter Physics and Materials’Science,Tata Institute of Fundamental Research,Homi Bhabha Road,Colaba,Mumbai -400005,INDIA(Dated:July 18,2008)In the paper,PRB 77,085118(2008),the authors conclude that the observation of Ti-doping induced half-metallicity in SrRu 1−x TI x O 3within the limit of local density approximations is not valid as the experimental results indicate insulating behavior.It was described that the metal-insulator transition (MIT)at x =0.5observed in this system appears due to the enhancement of on-site Coulomb repulsion strength,U with Ti substitutions,x .The MIT primarily depends on U and partially on x and/or disorder.All these conclusions are in sharp contrast to the experimental observations,which predicted Anderson insulating phase at x =0.5(ﬁnite localized density of states at the Fermi level).The hard gap due to electron correlation appears at much higher x (∼0.8).In addition,it is well established that homovalent substitution has negligible inﬂuence on on-site U (a local variable).These inconsistencies appear due to the fact that the calculated results representing the bulk electronic structure are compared with the experimental results dominated by surface contributions.The experimental bulk spectra,already available in the literature exhibit ﬁnite density of states at the Fermi level even for x ≥0.5sample,which suggests that the conclusion of half metallic phase in an earlier study is reasonable.Thus,the insulator to metal transition in these systems is driven by bandwidth,W rather than U and disorder plays dominant role in the metal-insulator transition.One needs to consider the bulk spectra to reproduce numerically the bulk electronic structure.PACS numbers:71.27.+a,71.30.+h,71.20.-b,79.60.BmRuthenates have drawn signiﬁcant attention in the re-cent times due to many interesting properties exhibited by these systems such as non-Fermi liquid behavior,un-usual magnetism,superconductivity etc.SrRuO 3forms in perovskite structure and is a ferromagnetic metal.It was observed experimentally that Ti doping at the Ru sites in SrRuO 3(SrRu 1−x Ti x O 3)thin ﬁlms leads to an interesting evolution of the electronic properties ranging from weakly correlated metal to a band insulator via sev-eral intermediate phases for diﬀerent values of x .1,2,3A recent study 4based on generalized gradient approx-imations (GGA)using V ASP package observed that Ti substitution at the Ru sites in SrRuO 3leads to a metal to half-metal transition around x =0.5.The authors conclude that such observation is in disagreement with the experimental observation of a metal-insulator tran-sition as a function of Ti-dopant concentration.It was suggested that a larger U would be more reasonable in the higher dopant concentration to achieve an insulat-ing ground state.In addition,it was predicted that ob-served metal insulator transitions in this system is pri-marily driven by on-site Coulomb repulsion.Disorder and/or Ti substitution are only partially responsible in determining the metal-insulator transition.All the above conclusions are in sharp contrast to the experimental results.Firstly,the experimental results 3based on transport measurements on thin ﬁlms suggest an Anderson insulating phase at x =0.5.This phase cor-respond to ﬁnite electronic density of states at the Fermi level,which are localized due to the eﬀect of disorder.Both transport and photoemission studies 1,3do not in-dicate signature of hard gap at x =0.5.The occurrence of hard gap is predicted at much higher Ti concentration (x ∼0.8).3It is clear that disorder play a signiﬁcant role in determining the electronic properties in this system.In addition,it is already well known 5,6that even in strongly correlated 3d transition metal oxides,the magnitude of on-site Coulomb repulsion strength,U is not signiﬁcantly sensitive to the homovalent substitutions.This is reason-able as U is a local variable.Thus,a conclusion of change in U with Ti substitution is unusual.Various photoemission studies of such ruthenates re-veal that the intensity of the correlation induced lower Hubbard band is signiﬁcantly weaker than the intensity of the coherent feature that represents the delocalized electronic states in the vicinity of the Fermi level.7,8Thus,the electron correlation strength is signiﬁcantly weak in these systems compared to that often found in highly correlated 3d transition metal oxides.This again rules out the possibility of Ti-substitution induced en-hancement of U in such a weakly correlated electron sys-tems leading to insulating phase.We believe that the inconsistencies observed here have a diﬀerent origin as described below.The results from band structure calculations represent the bulk electronic structure.Therefore it is desirable to compare the calculated results with the properties ob-tained from bulk materials and the spectral function rep-resenting the bulk electronic structure of the concerned systems.All the experimental results referred in the pa-per are obtained from thin ﬁlm samples.The photoemis-sion spectra provide the direct representation of the elec-tronic density of state.The experimental photoemission results referred in the paper have signiﬁcant surface con-2FIG.1:(color online)(a)X-ray photoemission spectra,(b) He I spectra,(c)bulk spectra and(d)surface spectra of SrRuO3(open circles)and SrRu0.5Ti0.5O3(solid circles),re-spectively.tributions.While it is often considered that suﬃciently thickﬁlms exhibit properties close to that expected in the bulk of the material,it is observed that the substrate induced strain persists even in thickﬁlms and the two-dimensional topology of theseﬁlms lead to signiﬁcantly diﬀerent electronic and magnetic properties.9Such con-ﬁnement eﬀects are used in numerous occasions to gen-erate quantum wells,in-plane magnetizations etc.In addition,experiments on various transition metal oxides reveal signiﬁcantly diﬀerent surface and bulk elec-tronic structures.7,8,10,11Even the samples in the form of thinﬁlms also exhibit surface-bulk diﬀerences in the electronic structure.8Moreover,in the present case,it has been demonstrated12experimentally that the surface and bulk electronic structure in SrRu1−x Ti x O3are signif-icantly diﬀerent.Part of the results are reproduced in the ﬁgure for a representative case.The experimental spec-tra were obtained using Gammadata Scienta analyzer, SES2002and monochromatized photon sources.The en-ergy resolution for x-ray photoemission(XP)and He II photoemission measurements were set at300meV and 4meV,respectively.The details of sample preparation and characterizations are described elsewhere.12In Fig.1(a)and1(b),we show the x-ray photoe-mission and He I spectra of SrRuO3(open circles)and SrRu0.5Ti0.5O3(solid circles).The spectral region shown here represents the density of states having primarily Ru 4d character as also found in previous studies.7,8,13,14It is evident that spectral lineshape changes signiﬁcantly with the change is photon energy.The He I spectra are most surface sensitive(∼80%).The surface contribution in the x-ray photoemission spectra is signiﬁcantly small(∼40%).Thus,the diﬀerent spectral lineshape in Fig.1(a) and1(b)indicates that the surface and bulk electronic structures are signiﬁcantly diﬀerent.The extracted surface and bulk spectra are shown in Fig.1(c)and1(d).It is evident that the ultraviolet pho-toemission spectra collected using thinﬁlms3as well as the bulk samples in the present study are very similar to the surface spectra obtained from bulk samples.In the surface spectra and in the He I spectra,the peak position of the most intense feature moves towards higher binding energies with increase in x.While such change may in-dicate a change in U in the surface electronic structure, it can have other origin too.For example,the crystal-lographic symmetry at the surface is diﬀerent from that in the bulk leading to diﬀerent crystalﬁeld eﬀect,sur-face defects,surface reconstructions etc.In fact it is be-lieved that the later eﬀects are more reasonable in these systems.7The bulk spectra exhibitﬁnite density of states at the Fermi level for all the x values studied.12Most impor-tantly,the bulk spectra and/or the raw spectra obtained by x-ray photoemission spectroscopy reveal that the en-ergy position of the electron correlation induced feature (lower Hubbard band)as marked by vertical dashed lines in Fig.1(a)and1(c)moves towards the Fermi level with the increase in Ti-dopant concentration in sharp contrast to the conclusions of the concerned paper.Most impor-tantly,this observation is visible in the raw data of the x-ray photoemission spectra and is independent of any data analysis procedure.Thus,it is important to extract the surface and bulk contributions from the experimen-tal spectra to obtain realistic representation of the bulk electronic structure.This also echoes the view that the insulating nature observed at these compositions are’An-derson insulator’kind,which correspond to disorder in-duced localizedﬁnite density of states at the Fermi level. We now turn to the question of half-metallic phase, which is also observed in earlier studies.15The main aim of that study was to grow half-metallic phase via Ti sub-stitution induced band narrowing.Since,the Ti3d levels has signiﬁcantly diﬀerent eigen energies compared to the eigen energies of Ru4d levels and Ti3d band is almost completely empty appearing above the Fermi level,the hopping of electrons from one Ru site to another via Ti sites is smaller than that expected for Ru-O-Ru hopping strength.Hence,Ti substitution leads to a signiﬁcant narrowing of the Ru4d bands.This in turn pulls the up spin band completely below the Fermi level and only the down spin band contributes at the Fermi level resulting to half metallicity.It is already known that the electron cor-relation strength is signiﬁcantly weak in these systems.7,8 Thus,the consideration of U would slightly enhance the energy gap in the up spin channel.The down spin chan-nel will continue to contribute at the Fermi level asﬁnite intensity is observed in the experimental bulk spectra. Thus,the conclusion of half metallic phase will not be inﬂuenced signiﬁcantly by the weak electron correlation in the vicinity of x=0.5compositions.In summary,the surface and bulk electronic struc-ture in Ti-substituted SrRuO3are signiﬁcantly diﬀerent. The bulk spectra in these ruthenates exhibitﬁnite den-3sity of states at the Fermi level for x as high as0.6in SrRu1−x Ti x O3.This is consistent with the other ex-perimental results indicating Anderson insulating phase rather than the hard gap insulators.The insulator to metal transition in these systems are primarily driven by bandwidth,W rather than U,and disorder plays an im-portant role in determining the electronic properties of these systems.∗Electronic mail:kbmaiti@tifr.res.in1J.Kim,J.-Y.Kim,B.-G.Park,and S.-J.Oh,Phys.Rev. B73,235109(2006).2M.Abbate,J.A.Guevara,S.L.Cuﬃni,Y.P.Mascarenhas, and E.Morikawa,Eur.Phys.J.B25,203(2002).3K.W.Kim,J.S.Lee,T.W.Noh,S.R.Lee,and K.Char, Phys.Rev.B71,125104(2005).4P.-A.Lin,H.-T.Jeng,and C.-S.Hsue,Phys.Rev.B77, 085118(2008).5M.Imada,A.fujimori,and Y.Tokura,Rev.Mod.Phys.70,1039(1998).6A.Georges,G.Kotliar,W.Krauth,and M.J.Rozenberg, Rev.Mod.Phys.68,13(1996).7K.Maiti and R.S.Singh,Phys.Rev.B71,161102(R) (2005).8M.Takizawa,D.Toyota,H.Wadati,A.Chikamatsu,H.Kumigashira,A.Fujimori,M.Oshima,Z.Fang,M.Lipp-maa,M.Kawasaki,and H.Koinuma,Phys.Rev.B72, 060404(R)(2005).9G.Cao,S.McCall,M.Shepard,J.E.Crow,and R.P.Guertin,Phys.Rev.B56,321(1997).10K.Maiti,Priya Mahadevan,and D.D.Sarma,Phys.Rev.Lett.80,2885(1998).11R.S.Singh,V.R.R.Medicherla,K.Maiti,and E.V.Sam-pathkumaran,Phys.Rev.B77,201102(R)(2008).12K.Maiti,R.S.Singh,and V.R.R.Medicherla,Phys.Rev.B76,165128(2007);ibid.,arXiv/0704.0327.13K.Maiti,Phys.Rev.B73,235110(2006).14David J.Singh,J.Appl.Phys.79,4818(1996).15K.Maiti,Phys.Rev.B77,212407(2008);ibid, arXiv/0704.0321.。

考研英语二阅读真题及答案

考研英语二阅读真题及答案2017考研英语二阅读真题及答案引导语：为了帮助大家更好地准备考研，以下是店铺为大家整理的2017考研英语二阅读真题及答案，欢迎阅读!英语二Section 1 Use of English1. [标准答案][C]how[考点分析]连词辨析[选项分析]? 根据语境，“新发现表明：快乐可能会影响工作__的稳定。

”[A] 为什么 [B] 哪里 [C] 怎样，多么 [D] 当…时候。

根据语义分析，C选项填入原文，译为“快乐可能会影响工作是有多么稳定”，C为正确选项。

2. [标准答案][B]In particular[考点分析]上下文语义以及短语辨析[选项分析][A] 反过来 [B] 尤其是 [C] 相反 [D] 总的来说根据前文语境，第二段第一句译为“根据近期的研究，拥有更多快乐的人的公司会投资更多”。

而第二句“_______那些在快乐氛围中的公司会做更多的研发以及发展。

“第二句是在第一句的基础上进一步强调说明，因此B选项更符合语境要求。

3. [标准答案] [D]necessary[考点分析]上下文语义及形容词词义辨析[选项分析][A]充足的 [B] 著名的 [C] 完美的 [D] 必要的首先，根据本句题干“That’s?because happiness is linked to the kind of longer-term thinking 3 for making investments for the future.”译为“因为快乐与对未来投资有______长远考虑相联系。

”要求填写形容词, 我们要考虑其搭配与其修饰成分。

空格处搭配介词for, 并且修饰“长远考虑”。

因此D选项最符合语境要求。

4. [标准答案][C]optimism[考点分析]上下文语义及名词词义辨析[选项分析][A]个人主义[B] 现代主义[C] 乐观主义[D] 现实主义本题考查同后缀的名词辨析。

根据原文主旨，探讨“happy people”与公司的关系。

ISTQB模拟试题

Question paper – 153. During this event the entire system is tested to verify that all functional information Structural and quality requirements have been met.A predetermined combination of tests is designed that when executed successfully satisfy management that the system meets Specifications.a. Validation Testingb. Integration Testingc. User Acceptance Testingd. System Testing7. The testing technique that requires devising test cases to demonstrate that each program function is operational is calleda. black-box testingb. glass-box testingc. grey-box testingd. white-box testing10. Performs sufficient testing to evaluate every possible path and condition in the application system. The only test method that guarantees the proper functioning of the application system is called as _____________a. Regression Testingb. Exhaustive Testingc. Basic Path Testingd. Branch Testing12. Majority of system errors occur in the _________ phasea. Requirements Phase.b. Analysis and Design Phasec. Development Phased. Testing Phase13 . ----- includes both Black box and White Box Testing featuresa. Gray Box Testingb. Hybrid Testingc. a&bd. None15.CAST stands fora. Computer Aided Software Testingb. Computer Aided Softwarw Toolsc. Computer Analysis Software Techniquesd. None16 Which one is not comes under international standarda. IECb. IEEEd. All of the above17 Which summarizes the testing activities associated with one or more test design specifications.a. Test Summary reportb. Test Logc. Test Incident Reportd. Test Script22 How much percentage of the life cycle costs of a software are spent on maintenance.a. 10%b. 30%c. 50%d. 70%26 System Integration testing should be done aftera. Integration testingb. System testingc. unit testingd. component integration testing30 Which rule should not be followed for reviewsa. Defects and issues are identified and correctedb. The product is reviewed not the producerc. All members of the reviewing team are responsible for the result of the reviewd. Each review has a clear predefined objective34 Typical defects discovered by static analysis includesa. Programming standard violationsb. Refering a variable with an undefined valuec. security vulnerabilitiesd. All Above38 When to stop Testing?a. Stop when scheduled time for testing expiresb. Stop if 75% of the pre-defined number of errors is detected.c. Stop when all the test cases execute with detecting few errors.d. None above39 What type of tools to be used for Regression Testinga. Performanceb. Record/Playbackc. a&bd. None40 The number of tests to test all control statements equals the cyclomatic complexitya. True45 In --- testing doesn't know anything about the sofware being tested; it just clicks or types randomly.a. Random testingb. Gorilla testingc. Adhoc testingd. Dumb monkey testing48 . --- is a very early build intended for limited distribution toa few key customers and to marketing for demonstration purposes.a. Alpha releaseb. Beta releasec. Test release documentd. BuildQuestion paper – 148. Validation involves which of the followingi. Helps to check the Quality of the Built Productii. Helps to check that we have built the right product.iii. Helps in developing the productiv. Monitoring tool wastage and obsoleteness.a) Options i,ii,iii,iv are true.b) ii is true and i,iii,iv are falsec) i,ii,iii are true and iv is falsed) iii is true and i,ii,iv are false.9. Which of the following uses Impact Analysis most?a) Component testingb) Non-functional system testingc) User acceptance testingd) Maintenance testing13. Functional system testing is:a) testing that the system functions with other systemsb) testing that the components that comprise the system function togetherc) testing the end to end functionality of the system as a wholed) testing the system performs functions within specified response times18. Match every stage of the software Development Life cycle with the Testing Life cycle:i. Hi-level design a Unit testsii. Code b Acceptance testsiii. Low-level design c System testsiv. Business requirements d Integration testsa) i-d , ii-a , iii-c , iv-bb) i-c , ii-d , iii-a , iv-bc) i-b , ii-a , iii-d , iv-cd) i-c , ii-a , iii-d , iv-b19. Which of the following is not phase of the Fundamental Test Process?a) Test Planning and Controlb) Test implementation and Executionc) Requirement Analysisd) Evaluating Exit criteria and reporting20. Which of the following techniques is NOT a black box technique?a) State transition testingb) LCSAJ (Linear Code Sequence and Jump)c) syntax testingd) boundary value analysis29. The structure of an incident report is covered in the Standard for Software Test Documentation IEEE 829 and is called as : -a) Anomaly Reportb) Defect Reportc) Test Defect Reportd) Test Incident Report30. Which of the following is the task of a Test Lead / Leader.i. Interaction with the Test Tool Vendor to identify best ways to leverage test tool on the project.ii. Write Test Summary Reports based on the information gathered during testing iii. Decide what should be automated , to what degree and how.iv. Create the Test Specificationsa) i, ii, iii is true and iv is falseb) ii,iii,iv is true and i is falsec) i is true and ii,iii,iv are falsed) iii and iv is correct and i and ii are incorrect35. Drivers are also known as:i. Spadeii. Test harnessiii. Scaffoldinga) i , ii are true and iii is falseb) i , iii are true and ii is falsec) ii , iii are true and i is falsed) All of the above are trueQuestion paper – 13Question 2Which of the following statements is MOST OFTEN true?A Source-code inspections are often used in component testing.B Component testing searches for defects in programs that are separately testable.C Component testing is an important part of user acceptance testing.D Component testing aims to expose problems in the interactions between software and hardware components.Question 8In a REACTIVE approach to testing when would you expect the bulk of the test design work tobe begun?A After the software or system has been produced.B During development.C As early as possible.D During requirements analysis.Question 13What is the main purpose of impact analysis for testers?A To determine the programming effort needed to make the changes.B To determine what proportion of the changes need to be tested.i i w . j ywiwgw.ajioyfsin g hf ar.inmfor a p e p p r C To determine how much the planned changes will affect users.D To determine how the existing system may be affected by changes.Question 27Which activity in the fundamental test process includes evaluation of the testability of the requirements and system?A Test analysis and design.B Test planning and control.C Test closure.D Test implementation and execution.Question 29What is typically the MOST important reason to use risk to drive testing efforts?A Because testing everything is not feasible.B Because risk-based testing is the most efficient approach to finding bugs.C Because risk-based testing is the most effective way to show value.D Because software is inherently risky.Question 36Which of the following are valid objectives for incident reports?i. Provide developers and other parties with feedback about the problem to enable identification, isolation and correction as necessary.ii. Provide ideas for test process improvement.iii. Provide a vehicle for assessing tester competence.iv. Provide testers with a means of tracking the quality of the system under test.A i, ii, iii.B i, ii, iv.C i, iii, iv.D ii, iii, iv.Question 39Which of the following are disadvantages of capturing tests by recording the actions of a manualtester?i The script may be unstable when unexpected events occur.ii Data for a number of similar tests is automatically stored separately from the script.iii Expected results must be added to the captured script.iv The captured script documents the exact inputs entered by the tester.v When replaying a captured test, the tester may need to debug the script if it doesn’t play correctly.A i, iii, iv, v.B ii, iv and v.C i, ii and iv.D i and v.Question 40Which of the following is determined by the level of product risk identified?A Extent of testing.B Scope for the use of test automation.C Size of the test team.D Requirement for regression testing.Question paper – 1111. Which of the following statements contains a valid goal for a functional test set?a. A goal is that no more failures will result from the remaining defectsb. A goal is to find as many failures as possible so that the cause of the failures can be identified and fixedc. A goal is to eliminate as much as possible the causes of defectsd. A goal is to fulfil all requirements for testing that aredefined in the project plan.28. Why is successful test execution automation difficult?a. Because the tools for automated testing require too much effort for learningb. Because the maintenance of the test system is difficultc. Because the test robot tools are restricted in their ability to recognize outputsd. Because the test robot needs to be supported by a test management.32. If a program is tested and 100% branch coverage is achieved, which of the following coverage criteria is then guaranteed to be achieved?a. 100% Equivalence class coverageb. 100% Condition coverage and 100% Statement coveragec. 100% Statement coveraged. 100% Multiple condition coverage33. This part of a program is given:-WHILE (condition A) Do BEND WHILEHow many paths should be tested in this code in order to achieve 100% path coverage?a. Oneb. Indefinitec. Twod. Four37. Why is incremental integration preferred over “big bang”integration?a. Because incremental integration has better early defects screening and isolation abilityb. Because “big bang” integration is suitable only for real time applicationsc. Incremental integration is preferred over “Big Bang Integration” only for “bottom up”development modeld. Because incremental integration can compensate for weak and inadequate component testingQuestion paper – 10Q23 Which of the following statements about component testing is FALSE?a)black box test design techniques all have an associated test measurementtechniqueb)white box test design techniques all have an associated test measurementtechniquec)cyclomatic complexity is not a test measurement techniqued)black box test measurement techniques all have an associated test design techniqueQ35 The standard that gives definitions of testing terms is:a)ISO/IEC 12207b)BS 7925-1c)ANSI/IEEE 829d)ANSI/IEEE 729Question paper – 95. Test are prioritized so that:a. You shorten the time required for testingb. You do the best testing in the time availablec. You do more effective testingd. You find more faults9. Which, in general, is the least required skill of a good tester?a. Being diplomaticb. Able to write softwarec. Having good attention to detaild. Able to be relied on12. A regression test:a. Will always be automatedb. Will help ensure unchanged areas of the software have not been affectedc. Will help ensure changed areas of the software have not been affectedd. Can only be run during user acceptance testing13. Function/Test matrix is a type ofa. Interim Test reportb. Final test reportc. Project status reportd. Management report14. Defect Management process does not includea. Defect preventionb. Deliverable base-liningc. Management reportingd. None of the above16. Software testing accounts to what percent of software development costs?a. 10-20b. 40-50c. 70-80d. 5-1017. A reliable system will be one that:a. Is unlikely to be completed on scheduleb. Is unlikely to cause a failurec. Is likely to be fault-freed. Is likely to be liked by the users19. Which of the following is not a characteristic for Testability?a. Operabilityb. Observabilityc. Simplicityd. RobustnessAnswer for Question paper – 153.C 7.C 10.C 12.A 13.A 15.A 16.B 17.C 22.D 26.C 30.C 34.C 38.A 39.B 40.A 45.D 48. B Answer for Question paper – 148.B 9.D 13.C 18.D 19.C 20.B 29.A 30.A 35.CAnswer for Question paper – 132.B 8.A 13.D 27.A 29.A 36.B 39.A 40.AAnswer for Question paper – 1111.B 28.B 32.B 33.C 37. AAnswer for Question paper – 1023.A 35.B。

Electronically Scanned Arrays

Electronically Scanned ArraysRobert J. MaillouxUniversity of Massachusetts, Amherst, MAMORGAN & CLAYPOOL PUBLISHING HOUSE2007ABSTRACTScanning arrays present the radar or communications engineers with the ultimate in antenna flexibility. They also present a multitude of new opportunities and new challenges that need to be addressed.In order to describe the needs for scanned array development,this book is a compact but comprehensive treatment of the scanned array, from the underlying basis for array pattern behavior to the engineering choices leading to successful design.The book describes the scanned array in terms of radiation from apertures and wire antennas and introduces the effects resulting directly from scanning, including beam broadening, impedance mismatch and gain reduction and pattern squint and those effects of array periodicity including grating and quantization lobes and array blindness.The text also presents the engineering tools for improving pattern control and array efficiency including lattice selection, subarray technology and pattern synthesis. Equations and figures quantify the phenomenon being described and provide the reader with the tools to trade-off various performance features. The discussions proceed beyond the introductory material and to the state of the art in modern array design.KEY WORDSAntenna array, phased array, scanning antenna, antenna design.PrefaceThis lecture is an introduction to the most important topics that dictate the behavior of scanning array antennas. It is intended to address the needs of engineers familiar with electromagnetics, microwave technology and antennas or antenna systems.The title of the book, Electronically Scanned Arrays employs the term “electronic scanning” rather than the more commonly used “phased”to emphasize that phase shifters and phase control are only one tool for array control. Of equal importance these days is the need for time delay devices and for active control of the amplitude distribution across the array.Much of this control can be done by analog phase shifters and switches, but future arrays will involve more use of digital and optical control where appropriate.The study of array antennas includes the electromagnetics of radiation and the interaction of various radiating array elements. It requires the understanding of a number of phenomenon peculiar to arrays and not the individual elements. Among these are the grating lobes that resulting directly from periodicity and many phenomenon that results from scanning, like the broadening of the array radiated beam, the reduction of gain, the varying interaction between elements and resulting impedance changes. These and other phenomenon characterize the behavior of scanning arrays.The lecture begins by introducing the basic parameters of arrays and presents methods for calculating in its simplest form, giving some mathematical detail for basic dipole elements in chapter 2 and arriving at the concept of an array element pattern. Chapter 3 introduces only a few basic techniques for pattern synthesis. This is a rich topic, but summarized here by several methods that are arguably by the most important ones.The final chapter treats one of the most fundamental issues of array design, how to group elements together to save on phase shifters, time delay units or digital beamforming ports. These groupings are called subarrays, and seeking optimized methods of forming subarrays is of continuing interest in this environment of increasing bandwidth and increasing array size.I am pleased to acknowledge the support of and many illuminating discussions with my colleagues at the Air Force Research Laboratory electromagnetic Technology Division over the years, and throughout numerous institutional name changes. I think my Air Force colleagues Allan Schell, Jay Schindler, Peter Franchi, Hans Steyskal, John Mcilvenna, Jeff Herd, Boris Tomasic, Livio Poles and David Curtis, and Arje Nachman of the Air Force Office of Scientific Research for the support of some of the fundamental aspects of antenna research.Robert J. MaillouxUniversity of Massachusetts, Amherst, MA。

心房颤动患者hs-CRP、P-选择素的检测及意义

心房颤动患者hs-CRP、P-选择素的检测及意义王赛英【摘要】@@ 近年来已有很多研究表明,心房颤动的发生和持续与炎症有关[1],高敏C反应蛋白(hs-CRP)可间接反应局部炎症程度,且具有较高的敏感性和精确性,被认为是炎性标志物之一.心房颤动引起体循环栓塞与心房颤动时左心房附壁血栓形成有关[2],其中血小板激活在血栓/栓塞疾病中起着重要作用.P-选择素是血小板活化的特异性指标,亦被认为是炎症标志物之一.本研究通过测定心房颤动患者hs-CRP、P-选择素水平,进一步探讨心房颤动者血小板功能激活与炎症水平的关系及P-选择素的临床意义.【期刊名称】《心电与循环》【年(卷),期】2011(030)003【总页数】2页(P239-240)【作者】王赛英【作者单位】310006,杭州市第三人民医院急诊内科【正文语种】中文近年来已有很多研究表明，心房颤动的发生和持续与炎症有关[1]，高敏C反应蛋白（hs-CRP）可间接反应局部炎症程度，且具有较高的敏感性和精确性，被认为是炎性标志物之一。

心房颤动引起体循环栓塞与心房颤动时左心房附壁血栓形成有关[2],其中血小板激活在血栓/栓塞疾病中起着重要作用。

P-选择素是血小板活化的特异性指标，亦被认为是炎症标志物之一。

本研究通过测定心房颤动患者hs-CRP、P-选择素水平，进一步探讨心房颤动者血小板功能激活与炎症水平的关系及P-选择素的临床意义。

1.一般资料选择2009年11月至2010年12月在我院急诊、心内科住院治疗的心房颤动患者共81例，根据2006年ACC/AHA心房颤动控制指南的定义，按心房颤动发作持续时间分为两组：阵发性心房颤动组（发作持续时间≤7d）42例，其中男性20例，女性22例，年龄40～86（68.14±10.49）岁，高血压25例（59.52%）；持续性心房颤动组（发作持续时间＞7d）41例，其中男性20例，女性21例，年龄53～85（69.49±7.58）岁，高血压25例（60.98%）。

托福听力tpo68全套对话讲座原文+题目+答案+译文

托福听力tpo68全套对话讲座原文+题目+答案+译文Section 1 (2)Conversation1 (2)原文 (2)题目 (4)答案 (7)译文 (7)Lecture1 (9)原文 (9)题目 (12)答案 (15)译文 (15)Lecture2 (18)原文 (18)题目 (21)答案 (24)译文 (25)Section 2 (27)Conversation2 (27)原文 (27)题目 (30)答案 (33)译文 (33)Lecture3 (35)原文 (35)题目 (39)答案 (41)译文 (42)Section 1Conversation1原文Student: Hi i'm i'm, i'm, Randy Beecham. I really need to speak with professor Clark right away. Could you get me into see her?Assistant: Well, she is conducting oral exams right now, I can't interrupt her. The exams began at 8:00 this morning and are scheduled to go on all day.Student: But I was supposed to take my oral at 9 this morning, and well I don't know what happened, my alarm clock didn't go off for some reason and I overslept.Assistant: Oh dear!Student: I know it's like, really embarrassing, when I open my eyes and saw with already 9:30 I just got here as fast as I could.Assistant: Well，since you didn’t show up your schedule time. The professor would probably consider it an unauthorized absence. I’m afraid that it will translate into an automatic failing grade for that portion of the exam.Student: Oh no, and I was so prepared, I stayed up all night studying. Is there any way I can maybe reschedule it？Assistant: I don't know what to tell you Randy. As I said professor Clark will be examining students to four o'clock today and all day tomorrow, then it’s the weekend.Student: What about like, first thing Monday morning？Assistant: No, Monday is not possible, exam week ends tomorrow when the dean, it's the dean who says the university’s rules on these matters, you know, not the professors. The dean is very strict about granting extensions except under extraordinary circumstances.Student: Um, so, I guess the defect of alarm clock wouldn’t account as extraordinary, huh.Assistant: I'm afraid we’re talking something more on the order of illness or if you had an unavoidable conflict, like an exam in another class schedule for the same time. But you know, since exam week isn't over yet, it probably would be worthwhile trying to speak with professor Clark, she might be able to find a solution.Student: You now, the oral part of the exams only an half hour long, do you think she’d be willing to stay later this afternoon or coming a littleearly tomorrow ?Assistant: I'm sure should do her best. But I can't speak for her of course. Student: But I can't just stick around all day waiting for her. Do you think she will be breaking for a lunch.Assistant: Well, I hope so for her sake, let me check her schedule again. Well, she's got student’s schedules to noon, then she has one hour break before the afternoon exams schedule begins. So yes, she apparently does plan to break for lunch.Student: Noon, ha.Assistant: That's what it says.Student: Okay, why don't I come back at noon then, but if you happen to see her in the meantime, would you please say I was here and that I'm really sorry I was late for my exam.Assistant: Of course, good luck!题目1.What problem does the student have?A. He is unsure about the material he needs to study for an exam.B. He missed the deadline for submitting a paper.C. He does not know when the exam period starts.D. He needs to reschedule an exam.2.What reason does the student give for missing an appointment with his professor?A. His alarm clock did not work properly.B. He was confused about the time of the appointment.C. He felt ill when he woke up that day.D. He had an exam in another class.3.Why does the woman mention the dean?A. To indicate that the dean will probably accept the student’s excuseB. To point out that the professor is not able to extend the exam periodC. To explain that extensions are not granted under any circumstancesD. To indicate that the student needs to report to the dean4.Why do the speakers think that the professor might be able to help the student?[Click on 2 answers.]A. The exam period has not ended.B. The professor may excuse the student from taking the exam.C. The professor may grant an extension of the exam.D. The oral exam takes only half an hour.5.What does the woman imply when she says this:Student: But I can't just stick around all day waiting for her. Do you think she will be breaking for a lunch.Assistant: Well, I hope so for her sake.A. The professor usually breaks for lunch during exams.B. The students enjoy eating lunch with the professor.C. The professor will get tired unless she takes a break.D. The exams will end early in the afternoon.答案D A B AD C译文1.学生：嗨！我是Randy Beecham，我真的需要和Clark教授马上谈一下。

to clarify confusing results

to clarify confusing resultsTo clarify confusing results, it is important to examine the data, identify any potential errors or inconsistencies, and gather more information if necessary. Here are a few steps to consider:1. Review the methodology: Ensure that the data collection and analysis methods are appropriate and reliable. Check if there were any limitations or biases that might have affected the results.2. Cross-reference with other sources: Compare the confusing results with data from other reputable sources to see if there are any discrepancies or consistencies. This can help identify any potential errors or validate the findings.3. Seek expert opinions: Consult with subject matter experts or professionals who are knowledgeable in the field to get their insights and interpretations. Their expertise can provide valuable context and help clarify any confusion.4. Conduct further research: If the confusing results persist, consider conducting additional research or data collection. This can involve exploring alternative methods, expanding sample sizes, or gathering more comprehensive information to address any gaps.5. Communicate transparently: It is essential to be transparent about the confusing results and share any clarifications or insights gained through the above steps. This clear communication will help avoid misunderstandings and ensure that the correct interpretation is understood by all parties involved.Remember that confusion can arise in any analysis, and having a systematic approach to clarify results can lead to better understanding and more accurate conclusions.。

Cultural and linguistic miscues

Cultural and linguistic miscues:a case study of international teaching assistant and academic faculty miscommunicationSusan Jenkins*Division of Teacher Education,University of Cincinnati,PO Box 210002,Cincinnati,OH 452210002,USAAbstractThis case study explores the communication patterns between Chinese international teaching assistants (ITAs)and academic faculty in a Mathematics Department.The faculty highly esteemed the ITAs as excellent mathematicians,but generally attributed negative causes to their behavior outside the realm of mathematics.The ITAs'polite deference and concern for maintaining appropriate face for unequal status interactions manifested itself as silence and avoidance in formal contacts with faculty,both in and out of the classroom.Most faculty interpreted this behavior as lack of motivation,isolationism and unwillingness to cooperate in ITA instructional assignments,or in improving their English.The students attributed their own behavior to stressful situational pressures and to the mixed messages they received from the faculty about the amount of time they should devote to English.Results are interpreted as supporting Gumperz'theory of conversational inference (1982:Gumperz,J.(1982).Discourse strategies .Cambridge:Cambridge University Press;1992:Gumperz,J.(1992).Contextualization and understanding.In A.Duranti,&C.Goodwin (Eds.),Rethinking context (pp.229±252)),and of attribution theoretical approaches.Implications for ITA training programs are discussed.72000Elsevier Science Ltd.All rights reserved.Keywords:ESL;ITA;Foreign students;Conversational inference;Attribution theory;Miscommunication 0147-1767/00/$-see front matter 72000Elsevier Science Ltd.All rights reserved.PII:S 0147-1767(00)00011-0International Journal of Intercultural Relations 24(2000)477±/locate/ijintrel*Tel.:+1-513-556-3590;fax:+1-513-556-2483.E-mail address:susan.jenkins@ (S.Jenkins).1.IntroductionThe internationalization of universities in the USA has become a reality through the presence in large numbers of foreign students on our campuses.Many of these graduate students ®nance their education through teaching assistantships awarded by the university.In return for instructional services in undergraduate education,they receive a tuition scholarship and a stipend (Byrd,1991).By far the largest numbers of international students are to be found in graduate programs in the natural sciences and engineering.The National Science Foundation reports that 40%of recipients of science and engineering doctoral degrees in 1995were non-US citizens,almost 75%of whom came from Asian countries (Hill,1996).Furthermore,as is true of the changing face of immigration patterns within the USA,the faculty is also assuming a multi-national guise.Approximately 15%of faculty in mathematics and the sciences,and 30%of those in engineering are foreign born (National Science Foundation,1996).A considerable body of research mainly located in the disciplines of teaching English as a second language and applied linguistics,has focused on international students as teaching assistants (Briggs et al.,1997).However,international teaching assistants (ITAs)and their professors view their primary goal as the pursuit of a graduate degree.Applied linguists and ESL faculty who prepare ITAs for their role as teaching assistants stand outside the disciplines of the ITAs they train.Thus,they are only peripherally aware of the academic life of the ITAs as graduate students within their own discipline.Research into the communication patterns within discipline speci®c contexts has focused on typical interactions in several professions.In education,research has been conducted on gatekeeping encounters in which miscommunication occurs when minority group members do not conform to pragmatic and linguistic (pragmalinguistic)expectations as de®ned by majority group norms (Bardovi-Harlig &Hartford,1990,1993;Erickson &Schultz,1982).Studies have also investigated communication in classroom and o ce hour interactions that reveal communication miscues (Shaw &Bailey,1990;Tyler,1995;Tyler &Davies,1990).Such studies have contributed important information to our understanding of the ways in which culturally in¯uenced discourse strategies may positively or negatively a ect communication.This paper extends that body of work with an analysis of the miscommunication between Chinese teaching assistants and the professors in their own department,mathematics.Knowledge of crucial aspects of the environment within which the mathematics faculty and students interact within a `bounded system'(Stake,1988),would be invaluable in understanding faculty expectations and the perceptions and behaviors that the students bring to ITA training programs.Thus,in order to prepare for future collaborative programs,the data for this study were gathered as part of an exploratory case study of the context of communication between the faculty and ITAs within the department.The research questions were broadly formulated to explore (1)views held by the faculty about the ITAs'roles,needs,and behavior as graduate students and ITAs,(2)views held by the students about their own roles,needs and behavior as graduate studentsS.Jenkins /International Journal of Intercultural Relations 24(2000)477±501478S.Jenkins/International Journal of Intercultural Relations24(2000)477±501479and ITAs,and(3)the degree of congruence between the perceptions of the faculty and the students.The approach to these questions was in¯uenced by two separate theories: Gumperz'(1982,1992)sociolinguistic theory of conversational inference,and the social psychology approach of attribution theory.According to Gumperz,meaning is constructed during the course of an interaction as listeners interpret the pragmalinguistic aspects of behavior,which Gumperz calls contextualization cues,that enable listeners to infer speakers' intentions.Thus``meaning in any face-to-face interaction is always negotiable;it is discovering the grounds for negotiation that requires the participants'skills'' (Gumperz,1982,p.14).In intercultural communication situations,inferences about speaker intent will be a ected by the participants'culturally speci®c use of contextualization cues and background knowledge.The less these are shared in a situated encounter,the higher the possibility for miscommunication.Once miscommunication has occurred because interlocutors do not have a common core of background knowledge,linguistic repertoire,or pragmatic skills, listeners will make sense of what they hear through the process of making attributions.Attribution theory attempts to provide``an answer to the question: what caused the observed behavior and its consequences?''(Jones&Nisbett,1972, p.ix).Thus,listeners attempt to seek causes for behavior even though they may have incomplete or faulty knowledge,as in intercultural communications.Kelley (1972)suggests that we make attributions quickly and economically as intuitive scientists based on our prior experience and preconceptions about similar data. Jones and Nisbett(1972)point out a discrepancy in the attribution processes of actors(those who perform)and observers(those who witness their performance). Actors tend to attribute their own undesirable behavior to situational factors, whereas observers tend to attribute the same behavior to the actors'personal characteristics.Each possesses di erent information,and certain aspects of behavior may have di erent salience to actors and observers,thus biasing their attributional processes.Kanouse and Hanson(1972)suggest that we are predisposed to®nd negative information more salient,and that as a result many of our attributions are also negative.Nisbett and Ross(1980)extend this position to argue that the attributions made by most people are fundamentally wrong, based as they are on error,bias and faulty reasoning.The implications for social relationships in general and intercultural communication in particular are obvious.1.1.Review of relevant literatureOne of the major variables a ecting intercultural communication is the distinction between collectivist and individualistic cultures(Triandis,1988). Triandis argues that collectivist cultures embrace a strong ingroup orientation which fosters munication patterns vary depending on ingroup vs outgroup identity.Hu and Grove(1991)point out that the collective orientation of China's values has been developed over some5000years of proud civilization.Today,the groups with which Chinese identify most closely are thefamily,school,work unit,and local community.University students are tightly knit into class groups of students studying the same major.The traditional role of the teacher goes far beyond the American concept to include concern for personal aspects of the students'lives.As the dispenser of knowledge,the teacher controls the classroom and does not expect student participation or interaction.Triandis'and Hu and Grove's analyses of Chinese values and cultures suggests that Chinese students in the USA may bring attitudes and beliefs about relationships and educational norms with them that will con¯ict with the American system.Pratt (1991)supports the interpretation of China as a collective culture based on his experience of teaching in China.The Chinese self,as centered in relationships with others,responds very di erently to American educational approaches that emphasize the development of students'individuality of expression,and the teacher as facilitator rather than dispenser of knowledge.These di erences,Pratt claims,account for Chinese students'silence and reluctance to express opinions in class discussions.In contrast,Garrot (1995)challenged the assumption that Asian students exhibit a collective orientation.She found that university students in China revealed both collectivism and individualism when information such as age,gender and major were considered.Garrot claims that culture-level analyses may not reveal changes occurring within a society,particularly among the young,and cautions teachers of Chinese students against broad generalizations.Interactions in academia are characterized by a status di erential between teacher and student,with higher status accorded to the teacher.Status is preserved by politeness strategies that maintain positive and negative face (Brown &Levinson,1987,p.13).Positive face represents a universal wish to be liked,or approved of.Negative face represents the desire to ``be unimpeded in one's actions'',or the right not to be imposed upon.Scollon and Scollon (1983)interpret such politeness strategies from an interethnic perspective.They view positive face as solidarity strategies based on equal status,and negative face as deference strategies,based on greater distance in status.Kim et al.(1996)found that individuals who valued interdependence used more negative face conversational strategies than did those who perceived themselves as independent.Thus,notions of appropriate politeness strategies are quite di erent among various cultures and language groups,and may a ect communication in academic interaction.One such politeness strategy is the use of silence.Scollon (1985)described the negative attributions made by westerners of the polite reserve of Athabaskans,which manifests itself as silent pauses between conversational turns.To westerners,the contextualization cue of silence is perceived as disruptive of smooth conversational ¯ow.Studies of vocal listening behavior among di erent language groups have shown very di erent timing and frequency distributions for the utterance of supportive listener vocalizations vis-a -vis silence.Clancy,Thompson,Suzuki and Tao (1996)discovered di erences in type and placement across languages of `reactive tokens',de®ned as those brief verbal and nonverbal responses by which a listener signalsS.Jenkins /International Journal of Intercultural Relations 24(2000)477±501480S.Jenkins/International Journal of Intercultural Relations24(2000)477±501481 attention and involvement.Mandarin employs very few tokens,and these only at turn transitions.Clancy et al.suggest that di erences such as these are the kinds of contextualization cues that would be noted as disruptive in intercultural communication.They suggest that English speakers might well ®nd the reserved Mandarin style``somewhat unnerving,leaving them wondering what the listener is thinking''(p.383).According to Shaw and Bailey(1990),the deferential silence of non-native speakers of English in the classroom can have a damaging e ect on their access to information.Their study of engineering classes demonstrated that the informal classroom culture in North America develops as a result of the dynamic oral negotiation between the professor and students during the®rst weeks of class. Thus,each classroom developed a speci®c culture depending on the outcomes of the professor±student negotiations.International students may be unable or unwilling to participate in such negotiating processes because of linguistic limitations,or because they are bound by their own more formal,teacher-centered schema of classroom behavior. Liberman(1994)found that Asian students at North American universities liked the¯exibility and variety of courses,the easy relationships between professors and students,the open exchanges of opinions in the classroom,and the emphasis on critical analysis.Yet,they had found it di cult to adjust to these aspects of academia,and some were troubled by what they interpreted as a lack of respect for the professor.Gao and Gudykunst(1990)and Gudykunst and Kim(1992)propose that cultural adaptation occurs as the uncertainty that is present in strange situations is reduced,with a concomitant reduction of the anxiety produced by the unfamiliar setting.Studies of the communication styles and preferences of international students in academic contexts illustrate the di culty in achieving such reduction. The studies have focused on the use of pragmalinguistic contextualization cues which do not accord with the expectations of American audiences,causing irritation or miscommunication.Liu(1995),reported that Chinese students had great di culty in automatically responding in the expected way to compliments,even though they knew the correct American English response.Liu attributes this to the fact that``deep-structure sociocultural transfer''(p.263),in¯uenced by long established®rst language contextualization cues,can only be replaced by immersion in the host culture and language.Similarly,Hinkel(1996)found that non-native speakers were aware of the norms of polite and appropriate behavior in the US,but were also critical of them when compared to those of their own cultures,and often chose not to follow the American norms.Hinkel speculates that her subjects may not have given high priority to learning appropriate politeness strategies because they were narrowly focused on obtaining their academic degrees:``while most subjects displayed an overt self-reported willingness to conform to L2pragmalinguistic norms,their self-reported behaviors largely did not support this inclination''(p.67).In the tradition of gatekeeping research(Erickson&Schultz,1982),Bardovi-Harlig and Hartford (1990,1993)analyzed conversations between native and non-native speakers of English in advising sessions with their professors.The non-native speakers were initially unable to make suggestions about the courses they wished to take,and used unacceptable reasons for rejecting advisor suggestions,such as lack of interest or fear that a course would be too di cult.Their defensive strategy required them to object to suggestions made by the advisor.In choosing such a strategy,the non-native speakers used `aggravators'and violated the maxim to ``make your contribution congruent with your status''(Bardovi-Harlig &Hartford,1993,p.281).Nevertheless,over the period of a semester,the non-native speakers were able to learn how to make acceptable suggestions.They did not succeed in eliminating unacceptable aggravators completely,indicating that pragmalinguistic competence needs time to develop.It is also interesting that the non-native speakers reported that they learned how to act appropriately in advising sessions by asking other non-native speakers rather than native speakers.Tyler (1995)and Tyler and Davies (1990)analyzed the discourse of Korean teaching assistants to identify the sources of frustration and unhappiness in the outcomes perceived by both participants.They concluded that miscommunication occurred because of the Korean TA's culturally determined need to present himself as modest,and to preserve an American student's face.These strategies resulted in discourse that the American undergraduates perceived as too tentative and vague and thus lacking authority.As a result both participants interpreted the other's behavior as uncooperative.Although studies such as these indicate that miscommunication occurs if linguistic minority groups do not adopt the pragmalinguistic norms required by the majority group,Blum-Kulka (1991)believes that even advanced learners may resist adopting the native speakers'pragmatic style in order to maintain their own cultural identity against attack by the target language culture.Additional pressures on pragmatic acculturation were revealed by Jin and Cortazzi (1993),who presented evidence that it was extremely di cult for Chinese students in English speaking universities to ignore the lifetime inculturation of a collective orientation.They could not risk alienation from their ingroup by adopting the norms of the host culture,which were unacceptable to the group.Zimmerman (1995)observed that frequency of contact and interaction with American students was the main determiner of acculturation for foreign students.The international students in her study also preferred to rely on informal peer grapevine systems for essential information rather than approaching knowledgeable university faculty and sta .The studies described above suggest that in communication contexts in which the norms of behavior are de®ned by the majority language group,the onus is on the minority language group to modify its pragmalinguistic behavior to conform to majority language behavior.Furthermore,perceptions of successful intercultural communication in situations of social inequality may depend on the ability of the lower status group to conform to the expectations of the higher status group.Such is the case in higher education for non-native English speaking ITAs who must interact with faculty.But the ITAs'dual roles as student andS.Jenkins /International Journal of Intercultural Relations 24(2000)477±501482S.Jenkins/International Journal of Intercultural Relations24(2000)477±501483 teaching assistant also demands that even when they are the higher status participant in interactions with undergraduates,the ITAs are expected to demonstrate the appropriate pragmalinguistic norms of the American classroom. Their preferred communicative style may result in inappropriate politeness strategies,such as silence,avoidance,or ck of opportunity to interact socially with Americans may negatively a ect access to the appropriate pragmalinguistic norms which provide the means to reduce uncertainty and anxiety in interactions.This case study of the communication patterns between faculty and ITAs in one university department provides a glimpse of the intercultural communication behavior within an academic context.It also adds essential information to the existing literature on international teaching assistant training,by demonstrating that the communication patterns within the students'home departments are powerful forces in determining the ways in which ITAs make sense of their multiple roles in the academy.2.Method2.1.Role of the researcherThe present study originated after the Mathematics Department approached me,as the Director of the ESL program to request an intensive English course for its Chinese ITAs because the department was unhappy with their oral English pro®ciency.In the event,two intensive courses were o ered,both of which were rated as successful by the students.However,interactions with the faculty and students during both programs hinted that unknown sources of dissatisfaction seemed to be limiting the mathematics faculty's optimism about the ITAs' potential,and their ultimate motivation to work on their English,thus prompting me to explore the issue further.As a researcher I went into the®eld well-known to many of the faculty and the students in the Mathematics Department.As the Director of the ESL program,I was consulted several times by administrators in the department as they were establishing their policies about English pro®ciency.There,my role was strictly limited to interpreting the meaning of TOEFL,SPEAK and other standardized test scores for the faculty,and I was never involved in their policy deliberations. During and after the two intensive English programs,I became a familiar and trusted®gure to faculty and students alike,as a colleague and as a teacher.As a foreign born white woman with expertise in teaching ESL,linguistics and inter-cultural communication,I viewed communication skills as a vital skill in academic success.Yet the students also saw me as a`gatekeeper'because of my involvement with the oral pro®ciency test.Because of these sources of possible bias,it was important to be vigilant in maintaining an`empathic neutrality'(Patton,1990)to ensure credibility of the data collection and analysis in an interpretive-constructivist approach(Lincoln&Guba,1985).For example,I was able to interview the faculty myself because they felt comfortable with me,and I was naõve about ways of knowing and doing in the Mathematics Department.However,I enlisted the help of an ESL teacher in interviewing the students to reduce the possibility that they might be less than candid because of my role as the ESL program administrator.Nevertheless,in spite of these and similar precautions,it is possible that my role may have impacted the data in unknown ways.Readers should be cautious in deciding whether to transfer the ®ndings to other settings and participants.2.2.SettingThe study was conducted at a large research university.Typical of many universities,the graduate programs in mathematics,the natural sciences and engineering were heavily dependent on foreign students.In these disciplines,foreign students comprised between 50and 80%of the graduate student population.Approximately 95%of the graduate students at the university received ®nancial support in the form of tuition scholarships or graduate assistantships.The majority of the foreign students came from The People's Republic of China,with India as the second highest country of origin.Foreign students whose ®rst language was not English were required to present a TOEFL score of 520for admission,but most graduate programs required higher scores.In the early 1990s,the graduate departments had raised their TOEFL score requirements to around 580in an attempt to admit students who would be able to pass the university's oral pro®ciency test.Thus,the average TOEFL score for graduate students from China was 600;for those from India it was 630.All graduate assistants were also required by state law to pass an oral pro®ciency test to qualify for instructional duties.About 75%of Chinese students initially failed the oral pro®ciency interview test,compared with 10%of the Indian students.The dilemma was that newly admitted graduate assistants who failed the test were limited to grading duties,leaving the departments scrambling to sta multiple sections of service courses at the last minute.The university had an ESL program which o ered three-credit courses during the semester.Because the Mathematics Department felt that their students needed a more intensive English experience,the ESL program was asked to develop a summer intensive English course to meet the students'language needs.2.3.Participants2.3.1.Faculty From the 45faculty members in the department,a representative sample was selected using the `network selection'method (Goetz &LeCompte,1984,p.79).Beginning with the faculty member who had initiated contact with the ESL program,the names of faculty who had expressed opinions in meetings or conversations about the needs of the ITAs were solicited.As names were added,each faculty member suggested other names until a total of nine faculty membersS.Jenkins /International Journal of Intercultural Relations 24(2000)477±501484S.Jenkins/International Journal of Intercultural Relations24(2000)477±501485had been nominated.When it appeared that no new names would be nominated to the list,®ve more randomly selected faculty members were contacted and asked to participate.All responded that they had never been involved with the ITAs and had no opinions to o er.Then they suggested Dr X,in each case naming someone who had already been suggested.All participants had taken part for many years in the critical events and decision making within the department,thus qualifying them as`good informants' because of their`thorough enculturation'in the department and`current involvement'with the issues of ITA training and English pro®ciency(Spradley, 1979,pp.47±49).Interestingly,the nominated group of eight males and one female consisted mainly of senior faculty who were administrators.They were the current and past department heads,the current and incoming graduate program directors,the instructor of the teaching seminar,the director of undergraduate education responsible for assigning TA duties,the professor responsible for supervising and evaluating TAs in the classroom,and two member of the graduate student admissions'committee.Seven men and one woman were professors,and one man was an associate professor.Two men were non native speakers of English2.3.2.StudentsParticipants were selected from the students who had taken the intensive English program.Several students had graduated or had transferred to other majors,so the original number of23had been reduced to a total of12.Seven students agreed to participate.All were Chinese(there was only one non-Chinese foreign student in the department at this time,plus®ve native speakers of English).There were two females and®ve males.Their ages ranged from25to33, and they had all been in the USA for at least1year,with the average length of time being17months.All had met the Department's TOEFL requirement of580. At the end of the intensive English program they all took the SPEAK test(the released form of the Test of Spoken English)with scores ranging from190to220. The university required a minimum score of230as demonstration of adequate oral English pro®ciency,but students who participated in the intensive program were deemed pro®cient if they scored220because they had received training in classroom presentation and communication skills.Two students scored220at the end of the program,and were each given a section of an introductory calculus course to teach.Other students were assigned to grading duties.Thus,the oral English pro®ciency of the students was generally below,or at the bare minimum level required by the university.2.4.Data CollectionData were gathered from several sources to ensure triangulation.To understand the perspectives of the participants,interviews were conducted with faculty and ITAs,and the re¯ective journals written by the students during their ITA training program were collected and analyzed.ITAs who were teaching their own classes。

武汉大学分子习题集

第一章：The Mendelian View of the World1. A combination of cleverness and, perhaps, luck led Mendel to use the garden pea forhis series of experiments. Describe the characteristics of this organism that made it an ideal choice for his studies.2.Explain whether a mammal (for example, the human) would be suitable for a similarstudy in inheritance.3.Define Mendel's two laws. Explain what they mean at the level of how chromosomesbehave following fertilization, and during meiosis. Do both laws always apply?4.What does it mean when an organism is said to "breed true" for a trait? What doesthis mean in terms of the organism's genotype?5.Provide an example of a trait that does not behave according to the classicalMendelian dominant-recessive relationship. Speculate as to what types of alleleswould interact in a true dominant and recessive fashion, and which might show amore intermediate interaction.6.Design a cross that would allow you to distinguish between two plants showing adominant phenotype, but could be either homozygous or heterozygous for thedominant allele.7.In an unusual rodent, coat color may be either red or brown. Two red females arecrossed independently with the same brown male. In several litters resulting fromthe cross with the male, female #1 produced 19 red offspring. In several littersresulting from the cross with the male, female #2 produced 11 red offspring and 9 brown. Describe the pattern of inheritance of coat color in this animal, and suggest the genotype of each of the parents.8.How many genetically distinct gametes can be formed for each organism having thefollowing diploid content:a.Aa Bb Cc Ddb.Aa Bb cc Ddc.AA BB Cc ddd.Aa bb CC DD9.For each case in question 8 (a--d), list the possibilities.10.Genes W, Y, Z assort independently and are dominant over their correspondingalleles w, y, z. Set up a cross between two individuals heterozygous for each trait[Ww Yy Zz x Ww Yy Zz].a.What is the frequency of offspring resulting from the cross who arehomozygous---that is, whose genotype is [WW YY ZZ]?b.What is the frequency of offspring whose phenotype is dominant for all threetraits?11.What properties of chromosomes suggested to early geneticists that they mightharbor the genetic material? What experiments confirmed these suspicions?12.Describe the chromosomal events that underlie genetic recombination. In what celltypes does recombination occur? Draw a crossing-over event in a cell, and show the gametes that would be produced by the event13.If a gene at one end of a chromosome has a recombination frequency of 50% with agene located at the center of the chromosome, and the centrally-located gene has an equivalent frequency of recombination with a third gene present at the opposite end of the chromosome, what is the recombination frequency between the two terminal genes? What can we say about the number of map units separating each of thesethree genes?14.You determine the frequency of recombination between two genes to be 50%. Whatcan you conclude about the relative chromosomal positions of the two genes within the genome? What other information or experimental results might help youdetermine whether the genes are on the sam e chromosome or on differentchromosomes?15.You are characterizing two genes present on a single plant chromosome, and wouldlike to determine the recombination frequency between them. Design anexperimental strategy for doing this. Assume that each of the genes includes adominant and recessive allele. Describe the genotypes of the plants you would need to cross, and explain how you would determine the rate of recombination.16.In a chromosome having the gene order A-B-C, if the frequency of recombinationbetween markers a and b is 0.15, and the frequency between markers b and c is 0.07, what is the rate of recombination between markers a and c? Why is it not possible to simply add these two frequencies together to obtain the recombination frequency for the outer markers?17.A cross involving three genes on a single chromosom e gives the following frequencyof recombinant progeny:AB BC AC25% 17% 12%What is the order of these three genes on this chromosome? What other cross could you perform to confirm your conclusion?18.The development of Mendelian genetics was accompanied by doubt about whetherthe types of genetic alterations observed in the lab could adequately explain themajor structural leaps seen during evolution. What type of genetic analysis put these doubts to rest, and what types of conclusions did they reach in order to do it?19.Following the rediscovery of Mendel's laws, researchers began their search for thechemical nature of the genetic material in earnest. Their search relied on a number of functional and physical properties that they knew the genetic material must possess.Name at least three of these properties.20.One of the earliest human traits to be successfully dissected at the molecular levelwas phenylketonuria, a metabolic disorder involving a defect in amino acidmetabolism. How does this m etabolic defect lead to a disease phenotype? Why were metabolic disorders such as this particularly useful for early studies into therelationship between genes and proteins?第二章：Nucleic Acids Convey Genetic Information1.In Griffith's experiments with virulence in bacteria, how did he demonstrate that thetransformation from nonvirulence to virulence was truly a hereditary change? In theabsence of such a demonstration, what other explanations could have accounted for his results?2.How did the experimental approaches of Avery, MacLeod, and McCarty vs. those ofHershey and Chase differ in demonstrating the nature of genetic material?3.Prion diseases are a group of neurodegenerative diseases that appear to be entirelytransmitted by proteins, with no essential role for nucleic acids. Keeping in mind the experiments of Avery et al., how do you think the absence of a role for nucleic acids in prion infectivity was experimentally established?4.Describe Chargaff's experiments addressing the nucleotide composition of DNA.What did his results say about the structure of DNA and about how DNA stores information?5.How did X-ray diffraction studies contribute to the discovery of the structure of DNA?What specific insights were provided by these studies?6.Explain how the design of the Meselson and Stahl experiments addressed thequestion of DNA replication.7.Draw the reaction catalyzed by DNA polymerase. What determines the sequence ofthe DNA produced by the reaction? Describe the experiments that were carried out to demonstrate this.8.On what basis did researchers reason that DNA was most likely not the template forprotein synthesis? What evidence led to the conclusion that the real template was RNA?9.Describe three major differences between the structures of deoxyribonucleic acidsand ribonucleic acids.10.What is the "central dogma" concerning the flow of genetic information? Is it alwaysvalid?11.What reasoning led Francis Crick to propose that an adaptor molecule intervenesbetween messenger RNA and amino acids? What did the adaptor turn out to be? 12.(a) You would like to isolate rRNA, tRNA, and mRNA from a particular cell type. Whatproperties can you rely on to distinguish between these three types of RNA---for example, in terms of their size, complexity, GC content, or abundance in the cell?(b) rRNA and mRNA both interact with ribosomes, but in fundamentally differentways. Describe the differences in the way each of these two types of RNA interacts with ribosomes.13.What is the advantage of having each amino acid specified by a sequence of threenucleotides? Why would two have been too few? Can you think of any reasons why four would be disadvantageous?14.In determining how m any bases are required to specify an amino acid (that is howmany bases constitute a codon), Francis Crick, Sydney Brenner, and colleagues useda class of mutagens that cause insertions and deletions of single base pairs in DNA.In gene X, predict the phenotype of mutants having, respectively, one through six insertion mutations, and explain how these results might be used to determine the coding properties of DNA.15.Once it had been established that codons consist of sets of three nucleotides, whatapproach did Nirenberg and Matthaei use to begin cracking the code? What was the first codon that they deciphered?第三章：The Importance of Weak Chemical Interactions1.You purify an enzyme and would like to determine whether it is composed of a singlepolypeptide chain or multiple chains held together by secondary bonds. How might you go about distinguishing between these possibilities?2.List three geometric features distinguishing atoms connected by a covalent bondversus those connected by a weak bond. How might these differences come into play when two macromolecules interact?3.Describe how strong and weak bonds are involved in the process of DNA replication,addressing the role of at least two examples of each type of bond.4.Which is more likely to involve the most significant loss of free energy: thehybridization of two 100 base pair stretches of single-stranded DNA to form a double helix, an enzyme binding to its substrate, or an antibody binding to an antigen?Explain your answer.5.What happens to the level of free energy during a spontaneous reaction? When freeenergy is lost during a reaction, what becom es of the energy? What occurs when a collection of atoms reaches its lowest energy state?6.The (G associated with a protein binding to an identical protein to form a homodimeris --2 kcal/mol. What is the K eq of this interaction at 25°C? What does this say about the binding of these proteins at this temperature?7.Describe and compare the three main types of weak chemical bonds that exist inbiological systems.8.Describe the importance of distance to van der Waals interactions. How does thisconstrain the shape of molecules that rely on such interactions for specific binding to other molecules?9.Describe the energetic forces underlying hydrophobic bonds. Describe thecontribution of each of these forces when two proteins specifically bind to each other in an aqueous solution.10.How much energy is associated with each of the following:a.covalent bondb.hydrogen bondc.ionic bondd.van der Waals bonde.average thermal energy of molecules at room temperaturepare the energy level of weak bonds and the average thermal energy ofmolecules at room temperature. What does this imply for the stability of weak bonds in a cell?12.Describe the relationship between the symmetry of electron distribution in a chemicalbond and the bond's energy, strength, and length.13.Describe the configuration of H2O in its liquid state, pointing out the condition ofhydrogen bonding to the interactions between the molecules. What properties ofwater allow it to interact with itself in such a regular way?14.Explain how water promotes the formation of secondary bonds among molecules inaqueous solutions.15.Why is it advantageous for the cell to use macromolecules whose shapes aredetermined by a collection of weak chemical bonds rather than solely by strongchemical bonds?第四章：The Importance of High-Energy Bonds1.Explain why molecules composed of weak covalent bonds serve as better energysources than do molecules composed of strong bonds.2.Why is glucose an excellent food molecule and carbon dioxide a poor one? Couldglucose serve as a primary carbon source for plants during photosynthesis?3.What is the average activation energy of a molecular transformation in the absenceof an enzyme? How does this energy level relate to the energy of the bonds broken during the transformation?4.Describe the role of enzym es in promoting chemical reactions, addressing specificallythe activation energy, the rate, and the G of the reaction. Approximately whatproportion of the molecular rearrangements in a cell depend on enzymes, and what proportion occur spontaneously?5.Do all the steps in a biochemical pathway involve a negative G? Explain why or whynot6.What percentage of free energy in a typical biochemical pathway is lost as heat orentropy? Can this loss be useful for the pathway, or is it simply an unavoidableconsequence of the inefficiency of biochemical processes? Explain your answer.7.You isolate a cellular molecule that appears to be produced in a synthetic reactioninvolving a slightly positive G. Describe at least two possible explanations for how the cell might achieve production of the compound despite the apparentlydisadvantageous energetics of this reaction. How could you experimentally address these possibilities?8.Both polypeptides and polynucleotides are unstable, and are spontaneouslyhydrolyzed in aqueous solution. Describe the physiological significance of thesereactions, and how the cell ensures that proteins and nucleic acids are nevertheless maintained in their polymerized state.9.Give two examples of reactions involving a group transfer. Describe how the transferinfluences the energy involved in the reactions.10.Draw the sequence of reactions involved in activation of an amino acid to participatein protein synthesis. Indicate changes in energy, coupled reactions, and reactionscatalyzed by enzymes.11.Discuss why ATP rather than ADP is preferred as an energy source to drive manybiochemical (synthesis) reactions. Give (at least) two examples.第五章：Weak and Strong Bonds Determine Macromolecular Structure1.Describe the four categories of amino acid side chains. What types of interactions arethe members of each of these categories likely to make?2.Outline the four levels of protein structure, giving a specific example of each.3.What are the two primary methods that can be used to determine a protein'sstructure? What are the strengths and limitations of each method?4.Describe the geometric features of the helix. Why is this structure especiallycommon? What are the weak bonds that stabilize the sheet?5.You are characterizing a DNA-binding protein, and have used genetic experiments toidentify a domain required for the interaction of the protein with DNA. Your secondarystructure analysis software predicts that the domain forms an helix, but you areunconvinced. What experiments could you perform to confirm the presence of anhelix in this region?puter algorithms are available that allow the prediction of secondary structuressuch as helices and sheets. What features of these structures do you think aredetected by such programs?7.How does single-stranded DNA-binding protein ensure specificity for single-strandedDNA as opposed to double-stranded DNA? What do you think the purpose of this protein might be, for example, during DNA replication?8.What features of the major groove make it especially useful for sequence-specificrecognition by proteins? Give at least two examples of DNA binding motifs that bindsprimarily to the major groove. Provide an example of a protein that does not use themajor groove to recognize its target. How does it accomplish its specific binding?9.Address the contribution made by non-specific contacts with the DNA backbone to thebinding affinity of typical DNA-binding proteins. What constraints are imposed on aprotein by relying on such contacts for sequence-specific DNA binding? What advantages are provided?10.Describe three features of RNA that can be used as a basis for recognition byRNA-binding proteins. How do they compare with the DNA features recognized byDNA-binding proteins?第六章：The Structures of DNA and RNA1.Draw an A:T base pair.a.Indicate how each base is joined to deoxyribose.b.Indicate which edge of each base pair faces into the major groove and whichinto the minor groove.e two different colors to indicate whether an atom is a hydrogen bonddonor or a hydrogen bond acceptor.2.Draw a G:C base pair.a.Indicate how each base is joined to deoxyribose.b.Indicate which edge of each base pair faces into the major groove and whichinto the minor groove.e two different colors to indicate whether an atom is a hydrogen bonddonor or a hydrogen bond acceptor.3.Other than hydrogen bonding, what else contributes to the stability of the doublehelix?4.Certain chemical agents such as nitrous acid can deaminate cytosine, converting itinto uracil. How might this explain why DNA contains thymine in place of uracil? 5.The virion DNA of an E. coli phage called X174 has the base composition: 25% A,33% T, 24% G, and 18% C. What do these data suggest about the structure of the phage's chromosome?6.Describe several reasons why the major groove is more often used by proteins torecognize specific DNA sequences than the minor groove. Consider the sequence AATCGG; what information, in terms of hydrogen bond donors, hydrogen bond acceptors, nonpolar hydrogen, and methyl groups, are provided by the major groove and minor groove, in each direction?7.Describe the ways in which DNA can vary from its ideal B structure, and contrast theB form of DNA with the A and Z forms. What factors or conditions favor thesedeviations from the B form and the choice between the three possible forms?8.Draw a graph showing the OD260 as a function of temperature for DNA isolated froma bacterial species having a high GC content, and one from a bacterial species havinga low GC content.9.In a collaborative project with a physicist colleague of yours, you decide to test theeffect of a new element he has discovered, fictionium, on the pitch of DNA in solution.You are familiar with the mica experiment described in the text, in which DNA is bound to mica and the exposed side is cut with DNAse I. You attempt to measure the pitch of your DNA using the same method, but much to your dismay you realize that fictionium strongly inhibits DNAse I, and so your experiment is an utter failure.Before you report the bad news to your colleague, what alternative experimental approaches could you take to determine this value?10.Consider a covalently closed, circular DNA molecule of length 10,500 base pairs andLk 950. What is the effect of the binding of 110 molecules of ethidium on Lk, Tw, and Wr?11.Which of the following structures have twist, which have writhe, and which haveboth?a. a closed circular DNA molecule lying flat on a planeb.double-stranded DNA wrapped around a nucleosomec. a circular, single-stranded oligonucleotided.an overtwisted telephone corde. a human chromosome12.Describe three differences between topoisom erase I and topoisomerase II. You havean experiment in mind that requires topoisomerase II, but not topoisomerase I, and would like to purify this enzyme from bacterial cells. Describe a purification strategy that would allow you to specifically isolate topoisomerase II, relying on the unique activities of each enzyme.13.Populations of the following types of molecules are incubated with the indicatedenzymes. Predict all possible products for each reaction.a.(a) complementary single-stranded circles + topoisom erase Ib.(b) negatively supercoiled DNA + eukaryotic topoisomerase IIc.(c) negatively supercoiled DNA + topoisom erase I14.Draw the reaction that causes RNA to hydrolyze at high pH.a.Why is RNA more sensitive to high pH than DNA?b.What is the function of Mg2+ in RNA molecules?15.While RNAse P contains both RNA and protein, the enzymatic activity is known toreside in the RNA component. What is the role of the protein, then, in this enzyme?What kind of experiment could be used to demonstrate that the activity of theenzyme resides in the RNA component, and not in the protein? The so-calledhammerhead ribozyme mediates its own cleavage. It was initially identified in plant virions and has been shown to have the secondary structure depicted in the figure below. The position of cleavage is marked by the arrow in the figure. (Note that Ni can be any base, and the subscript I is used to denote N at a particular position.) Describe the chemical nature of the cleavage reaction, indicating which chemical group of which base is attacking which other chemical group.16.The so-called hammerhead ribozyme mediates its own cleavage. It was initiallyidentified in plant virions and has been shown to have the secondary structuredepicted in the figure below. The position of cleavage is marked by the arrow in the figure. (Note that Ni can be any base, and the subscript i is used to denote N at a particular position.) Describe the chemical nature of the cleavage reaction, indicating which chemical group of which base is attacking which other chemical group.17.Instead of using a single-stranded molecule like that shown in Question 16, atwo-stranded hammerhead, as shown in the figure below, is often used.a.What is the major consequence of using a two-stranded structure?b.Is it feasible for a single-stranded DNA to be an enzyme? Explain. How mightthe lack of a 2'-OH group in DNA be remedied?18.The Fragile-X syndrome is the most common inherited form of mental retardation inhumans. The gene causing the disease has been cloned and shown to encode anRNA-binding protein that binds to a diverse yet specific pool of mRNA species in the brain. Based on what you know about RNA structure, do you think it likely that this protein binds to these RNA molecules using a similar mechanism that proteins use to bind DNA? Explain why or why not, and if not, propose another way that this protein may recognize these RNA species.19.Recall the approach described in Box 6-2 that allowed us to conclude that DNA insolution has a helical periodicity of 10.5 base pairs per turn of the he lix. Now consider scenarios in which the solution to the question of helical periodicity is either 10 or 11 base pairs, rather than 10.5. Design experiments comparable to those described in Box 6-2, using cccDNAs of the appropriate lengths, and provide anticipatedexperimental data which would suggest that DNA has a helical periodicity of 10 base pairs or of 11 base pairs per turn of the helix.第七章：Chromosomes, Chromatin, and the Nucleosome1.How is the 2 meters' worth of DNA in every human cell compacted to fit into a nucleusof less than 15 microns? Describe the various ways in which DNA is compacted,describing the proteins or structures involved at each level, and the degree ofcompaction provided.2.You isolate nuclei from three different sources, partially digest the chromatin withmicrococcal nucleus, extract the DNA, and run it on a gel. You observe the following patterns:3.Explain what these ladders represent in each of the three samples. Why are the patterns different? If you digested each of the three samples more thoroughly, what would the pattern look like?4.List the five major types of histone proteins, and describe what role each of themplays in the nucleosome. Based on what you know about them, which histoneprotein(s) do you think might be the most evolutionarily conserved? Which are likely to be the least conserved?5.What are the "tails" of the histone proteins, and how are they distinguished from therest of the protein?6.Describe the interactions between the histones and DNA that determine the DNA'spath around the histone octamer. How does the manner of DNA wrapping around the nucleosome alter DNA topology?pare the molecular interactions that occur between the histone proteins and DNAand those that occur between DNA and sequence-specific binding proteins such as transcription factors. How do the differences in binding mechanisms relate to the different roles of each of these types of proteins?8.Once a nucleosome has formed on a particular stretch of DNA, how stable is it?Describe the processes---either passive or active---that can destabilize nucleosomes in vivo. Why is it important that nucleosomes can be destabilized?9.How frequently are nucleosomes precisely positioned on the DNA? Describe howspecific nucleosome positioning can promote transcriptional activation, or,alternatively, prevent it. If you wanted to precisely position a nucleosom e on a given stretch of DNA, how could you do it?10.Describe the process by which the histone tail modifications that are present at agiven genomic region are maintained during DNA replication. How does thedistribution of histones during replication compare to the semi-conservativereplication of DNA itself?11.You are characterizing a transcriptional repressor in your favorite organism, and youperform a co-purification experiment to identify proteins that physically interact with the repressor. Using this approach, you identify an interacting protein that appears to have deacetylase activity. Speculate as to how this enzyme could be involved in transcriptional repression. How might you test your hypothesis?12.What are the roles of bromodomains and chromodomains in regulating nucleosomalfunction? What is the functional significance of the interaction of proteins containing such domains with acetyl transferases or with methylating enzym es?13.Outline the steps by which a nucleosome is assembled in the presence of histonechaperones. What is produced when the following combinations of molecules are incubated together:a.H3 and H4b.H2A and H2Bc.purified histones and DNAd.H2A, H2B, H3, H4, DNA, and histone chaperones14.What effect does nucleosome formation have on the following properties of a closedcircular DNA molecule:a.its linking numberb.its writhec.its degree of compaction15.Address the general properties of the chromatin within the following types of DNA:a.DNA undergoing active transcriptionb.DNA within a mitotic chromosomec.DNA immediately after passage of the replication forkd.centromeric DNA第八章：The Replication of DNA1.(a) Draw a schematic diagram of the primer:template junction, labeling the 5' and 3'ends of each of the strands. Indicate where deoxynucleotides are added during the process of DNA replication.(b) Draw the reaction by which the deoxynucleotides are added to a growing DNAstrand during replication. What happens to the pyrophosphate that is produced inthis reaction?2.Describe two ways by which DNA polymerase ensures that the correct base is addedto the growing polynucleotide chain during replication, addressing what thesemechanisms have in common, and how they differ. What is the contribution of these mechanisms toward the overall fidelity of DNA replication?3.Briefly summarize the palm, thumb, and finger domains of DNA polymerase, andexplain how they contribute to replication. What is the role of the metal ions in the palm's activity?4.What prevents ribonucleotides from being incorporated into the growing DNA strandduring replication of the genome? In what aspect of replication are ribonucleotides used, and what ultimately happens to them?5.Okazaki discovered the fragments named after him by briefly exposing replicatingDNA to radioactively-labeled nucleotides, and then separating the labeled DNAfragments by size. Using this method, he identified two populations of fragments.Describe what these two populations must have looked like. Why was it important to use a short exposure to the radioactive label rather than a longer one?6.The size of Okazaki fragments differs in different organisms. What might influencethis size? How might you test this possibility?7.How is the DNA unwound at the replication fork? What effect does this have on theDNA upstream of the fork, and how does the cell deal with this effect?8.Address how cooperative binding contributes to SSB function during DNA replication.What is the advantage of such binding for SSB activity?9.Sliding clamps are topologically-closed rings that can encircle the DNA double helix.How, then, are they able to get on and off the DNA? What purpose is served by this striking topology?。

两种利用micro-CT测量小鼠牙周炎模型牙槽骨吸收的方法比较

两种利用micro-CT测量小鼠牙周炎模型牙槽骨吸收的方法比较崔迪;张杨珩;张婷;魏挺力;闫福华【摘要】Objective To evaluate two methods measuring alveolar bone loss by micro computed tomography (micro-CT)based on periodontitis model in mice.Methods The silk ligatures were tied around the right maxillary second molars of mice to induce periodontitis model.The right half maxillaries of mice model were harvested for micro-CT analysis.Three dentists were recruited for the measurement with two different methods:Modified tomography (T) method and reconstruction (R) method.Accuracy and consistency of each method were estimated by standard deviation (SD).Results The SDs of R method managed by the same operator (measurement for 3 times) or different operators (3 operators) were 34.87μm and 35.67 μm respec tively,while that of T method was 7.82 μm and 14.24 μm respectively.The SDs of T method were significantly lower than those of R method (both P＜0.05).Conclusion T method is more accurate and consistent than R method for evaluating alveolar bone loss in mice periodontitis model.%目的比较两种利用微计算机断层扫描(micro-CT)测量小鼠牙周炎模型牙槽骨吸收的方法.方法结扎小鼠右侧上颌第二磨牙建立牙周炎模型,分离其右侧上颌骨后进行micro-CT扫描.由3名医师分别采用重建法(R法)和改良的断层测量法(T法)进行牙槽骨测量,分析比较两种测量方法的一致性和稳定性.结果不同测量者采用R法进行测量的标准差(SD)为35.67μm,采用T法的SD为14.24 μm,差异有统计学意义(P＜0.05);同一测量者采用R法测量3次所得结果之间的SD为34.87μm,采用T法的SD为7.82 μm,差异有统计学意义(P＜0.05).结论采用T法测量小鼠牙周炎模型牙槽骨吸收的一致性和稳定性均优于R法.【期刊名称】《中国介入影像与治疗学》【年(卷),期】2017(014)003【总页数】5页(P173-177)【关键词】牙槽骨吸收;牙周炎;体层摄影术,X线计算机【作者】崔迪;张杨珩;张婷;魏挺力;闫福华【作者单位】南京大学医学院附属口腔医院牙周科,江苏南京 210008;南京大学医学院附属口腔医院牙周科,江苏南京 210008;南京大学医学院附属口腔医院牙体牙髓科,江苏南京 210008;南京大学医学院附属口腔医院口腔种植科,江苏南京210008;南京大学医学院附属口腔医院牙周科,江苏南京 210008【正文语种】中文【中图分类】R816.98牙槽骨吸收是牙周炎的典型病理改变，也是判定患牙愈后的重要依据之一[1]。