第一篇:水利水電專業英語論文--英文對照及翻譯
English for hydraulic and hydroelectric engineering
Earth and rock dam
Summary Earth and rock dam, with another name as “local material dam”,is mainly built with earth and rock materials near the site.It can be classified based on the materials it used, earth dam mainly with earth, sand, grit, and gravel, and rock dam mainly with rock ballast, gravel, and exploded rocks.Features of earth and rock dam Strong points With convenient supply of materials, many building materials such as steel, cement, and timbers can be saved.With granular structure more suitable to foundation deformation, it demands less on the foundation.Very flexible from simple artificial filling to highly mechanized construction, the procedure become simple, the construction become efficient, and the quality guarantee become easy.Simply structured, the cost is low, the operation is convenient, works is reliable, and maintenance and height adding is convient.Weak points Overflow not allowed, spillway has to be built.Diversion less convenient, cost increases.Section larger, earth to be filled is easy to be affected by climate.This kind of difficult means possible extention of time limit and cost increase
概述
土石壩又稱“當地材料壩”,主要由壩址附近的土石料填筑而成,根據壩體所用材料不同又可分為土壩和堆石壩。壩體材料以當地土料和砂、砂礫、卵礫為主的稱土壩,以石渣、卵石、爆破石料為主的稱堆石壩。
土石壩的特點
優點
筑壩材料就地取材??晒澥〈罅夸摬?、水泥、木材等建筑材料。適應地基變形能力強。土石壩散粒體結構具有適應地基變形的良好條件,對地基的要求比混凝土壩低。施工方法選擇靈活性大。能適應不同的施工方法,從簡單的人工填筑到高度機械化施工都可以;且工序簡單、施工速度快,質量也易保證。結構簡單。造價低廉、運行管理方便、工作可靠,便于維修加高。
缺點
壩頂不能溢流,常須另開溢洪道施工。導流不如混凝土壩方便,因而相應增加了工程造價壩體斷面大,土料填筑的質量易受氣候影響。這給施工帶來困難,甚至延長工期、增加造價。
English for hydraulic and hydroelectric engineering Earth and rock dam types Based on constructing ways, earth and rock dams can be classified into rolled ones of earth & rock, thrown rock-filled ones, rock-filled ones with directional detonation, ones with earth thrown into the water, and ones filled by hydraulic forces.Among them, rolled ones are most popular.Based on the earth proportion and the location of anti-seepage parts, there are homogeneous(even-granular)dams, zoned earth dams, and dams with artificial anti-seepage materials.Strong points of homogeneous dams: one fold materials, simple process weak points: flat gradient, large section, weather-limited, strong water pressure in holes.Zoned dams are classified into ones with core anti-seepage and ones with front anti-seepage.Less amount of earth, less affect of season.interfering with the filling of the dam body.Less interference with the construction of the dam body.weaker anti-earthquake and uneven sinking.The anti-seepage parts of dams with artificial anti-seepage materials use asphalt concrete, reinforced concrete or other artifical materials.Sometimes, the anti-seepage parts are in the dam front facing the upstream, sometimes, they are at the core of the dam.Working conditions
Trapeziform section Earth-rock dam is a water retaining structure built with loose granules of earth and rocks filled and roller compacted.With weaker strength between these granules, both upsteam and downsteam slopes have to be kept at a certain degree to avoid landslide.So
土石壩的類型
土石壩按施工方法的不同可分為:碾壓式土石壩,拋填式堆石壩,定向爆破堆石壩,水中倒土壩和水力沖填壩等。其中尤以碾壓式土石壩應用最廣。
按土料在壩體中配置和防滲體的位置不同,又可分為均質壩,分區壩,人工防滲材料壩。均質壩優點:材料單
一、工序簡單;缺點:壩坡較緩、剖面大,受氣候限制,壩體孔隙水壓力大,高壩很少采用。分區壩分心墻壩、斜墻壩等,前者優點:土料占總方量比重不大,施工受季節影響小。缺點:心墻與壩體大體要同時填筑,相互干擾。后者優點:與壩體施工干擾小。缺點:抗震性能和適應不均勻沉陷的能力不如前者。人工防滲材料壩的防滲體由瀝青混凝土、鋼筋混凝土或其他人工材料組成,其余部分由土石料筑成。其中防滲體在上游的稱為斜墻壩(面板壩),在壩體中央的稱為心墻壩。
工作條件
梯形剖面
土石壩是由松散顆粒土石料填筑碾壓而成的擋水建筑物。由于土粒間的抗剪強度小,上下游坡如不維持一定的坡度,就可能發生坍塌現象。所以,土石壩的剖面一般呈梯形。失穩的形式則是壩坡滑動
English for hydraulic and hydroelectric engineering the dam section is usually trapeziform.It can be destablized in two ways, simple slope sliding and sametime sliding of slope and foundation caused by shear damage.It's a difference from other structures
Seepage effects With a large section, the dam is generally kept from entire sliding unless caused by weak interlayers.Effected by water levels at the upsteam and downsteam, seepage is easy to happen with streams passing the faying surfaces between the dam and foundation, and between dam earth and concrete buildings.The seeping streams form a free water surface inside the dam.Under the surface, all the earth body is saturated.Dipped in the water, the earth become lighter in effect.And its angle of internal friction is narrowed, and cohesive force weakened.With the hydrodynamic pressure from the seeping steams, more sliding of dam slopes is possible.When seeping steams move in soil, the dam body and foundation will be deformed from too steep hydraulic gradient.Sometimes the dam even crashes.Scour effect Its anti-scour ability is weak because the cohesive force between earth granules is small.On the one hand, the rain water enters the dam and lower the stability of the dam, and on the other hand, the rain scour the dam surface along the slope.At the same time, the waves inside the reservoir also wash out the dam surface, putting the surface in the risk of being damaged.Sometime, landslide even happens due to this.So effective protecting measures
或壩坡連同地基一起滑動的剪切破壞,這是與其他建筑物的不同之處.滲流影響
土壩擋水后,由于壩體斷面較大,除壩基有水平軟弱夾層外,產生整體滑動的可能性較小。但在上下游水位的作用下,水流經過壩身及壩基(包括兩岸)的結合面和壩體土與混凝土等建筑物的結合面易產生滲漏。滲流在壩體內形成自由水面,浸潤線以下的土體全部處于飽和狀態。飽和區的土體受水的浸泡而使土的有效重量減輕,并使土的內摩擦角和粘結力減小。同時,滲透水流對土體還有動水壓力的作用,這些力增加了壩坡滑動的可能性。滲透水流在土壤中運動時,如滲透坡降超過允許滲透坡降,還會引起壩體和壩基的滲透變形,嚴重時會導致壩的失事。
沖刷影響
由于土料顆粒間的粘結力很小,因此土石壩抗沖能力較低。雨水一方面侵入壩內降低壩的穩定性,另一方面將沿壩坡面下流而沖刷壩面;庫內風浪對壩面也將產生沖擊和淘刷作用,使壩面容易受到破壞,甚至滑坡。因此,上下游壩坡均需采取有效的保護措施。
English for hydraulic and hydroelectric engineering have to be taken for dam slopes both upstream and downstream.Sinking effect The dam body and foundation will sink under their self weight and water load besides the space between earth granules.If it sinks too much, the elevation level will not be sufficient, and then the operation of the dam will be affected.And, too much uneven sinkage will cause fracture of the dam boday, and even a seepage passage, putting the dam at risk.Other effects In freezing regions, an ice-covered layer will be formed over the reservoir when the temperature is below 0 degree.Then the bank slope and dam slope will be frozen together with the ice.When the ice expands, slopes will be pressed.In this way, the protecting slopes will be damaged.Besides, the clay above the water level will have holes and cracks effected by freezing and thawing.In summer, with water lost, the clay will cracked, making seepage much easier.Earthquakes have to be taken into account.They can make landslide more possible.If the foundation is made of silty sand, liquidified damage is more possible.Materials for building earth and rock dam Obtaining raw material locally is a basic design principle.Generally speaking, familiar earth and rock materials can be used.exceptions include swampy soil, bentonite, surface soil, and other soil materials containing organic matter not completely decomposed.therefore, dam type is often
沉陷影響
由于土料間存在孔隙,在壩體自重和水荷載作用下,壩體和地基(土基)都會由于壓縮而產生沉陷。沉陷量過大會造成壩頂高程不足而影響壩的正常工作;過大的不均勻沉陷量還會引起壩體開裂,甚至造成滲水通道而威脅大壩安全。
其它影響 在嚴寒地區,當氣溫低于零度時,庫水面結冰形成冰蓋層。當岸坡及壩坡凍結在一起,冰層的膨脹,對壩坡產生很大冰壓力,易導致護坡的破壞。位于水位以上的壩體粘土,在凍融作用下會造成孔穴、裂縫。在夏季,由于含水量的損失,上述土壤也可能干裂引起集中滲流。在地震區筑壩,還應考慮地震影響。地震的作用增加壩坡坍滑的可能性。粉沙地基在強烈振動作用下還容易引起液化破壞。
土石壩的筑壩材料
就地取材是土石壩設計的基本原則。一般而言,常見的土石料(沼澤土、斑脫土、地表土及含有未完全分解有機質的土料除外)均可用作筑壩材料。因此,應根據壩址附近土石料的具體條件選擇壩型。土石料場的選擇宜儲量充足,以近為原則,具體選用須
English for hydraulic and hydroelectric engineering determined based on availability of earth and rock materials nearby the site.stockyard must be rich in storage and near in distance.As for the selection, technical and economic factors will be considered.The dam body is mainly made up of dam shell, antiseepage, drainage, and protection slope.They work under different conditions, so they demand differently.Materials must be durable and suitable to their purpose.Antiseepage and structure of dam crest Seepage-proofing work for a dam must be based on structural and constructing requirements, reducing seepage gradient, down-stream saturation line, and seepage to an allowance extent.We can use terrene seepage-proofting materials and artificial materials including asphalt concrete and reinforced concrete.terrene materials are more used.Road is built on crest.If traffic is necessary, road has to be built based on relevant standard.If traffic is not anticipated, single-layer masonry or gravels is sufficient for resisting rain scouring.anti-wave wall is built upstream, and railings are built downstream.the wall, usually 1 to 1.3 meters high, is built with stone masonry or reinforcing concrete.its foundation must be firmly buried in the dam, protruding into anti-seepage.For the sake of rain, the road on the crest is usually built with slopes on one side or on both sides.When there is a anti-wave wall, the slope is towards downstream, and there will be a lengthways drainage downstream the dam crest for gathering water.The water will go downstream through drainage.通過技術經濟比較而定。土石壩壩體主要由壩殼、防滲體、排水設備、護坡等組成。由于他們工作條件不同,因而對材料的要求也不同。筑壩材料應具有與其使用目的相適應的工程特性,并具有較好的長期穩定性。
壩的防滲體和壩頂構造
壩的防滲體必須滿足將滲透坡降、下游壩體浸潤線及滲流量降低到允許范圍內,還要滿足結構上和施工上的要求。作為壩的防滲體的材料有土質防滲體,人工材料(瀝青混凝土,鋼筋混凝土),其中用的最多的是土質防滲體。在壩頂應該設路面,如壩頂有交通要求,則應按道路要求設計,如沒有交通要求,則可用單層砌石或礫石護面以防雨水沖蝕。壩頂上游側通常設防浪墻,下游側設攔桿。防浪墻高度通常為1~1.3米。用漿砌石或鋼筋混凝土筑成。墻的基礎應牢固地埋入壩內,伸入防滲體內。為排除雨水壩頂路面通常向兩側或一側做1~3%的斜坡。有防浪墻時坡向下游,并在壩頂下游側設縱向排水溝,以便匯集雨水,經坡面排水溝排至下游。
English for hydraulic and hydroelectric engineering Dam slope
Influencing dam stability and construction directly, dam slope is determined by dam type, dam height, dam scale, material of dam body and foundation, load to bear, and conditions for construction and operation.Generally speaking, dam slope is initially designed according to projects completed.Then a proper section is decided after calculation in terms of stability.To slopes made of sand and soil in a rolled dam, their gradient is between 1:2 and 1:4.For dam foundation which is weaker, the gradient should be slow.For slope design, we have to consider the shearing strength which of earth will be reduced due to being soaked in up-stream water.So if the upstream and downstream slopes are made of same earth materials, the former one has to be slow.for earth dams with inclined soil walls, their upstream slopes are slower than those of core dams, and their downstream slopes are steeper than those of core dams.for homogeneous dams of sandy loam and loam, their slopes are slower than those of dams made of sand and gravels.slopes of homogeneous dams made of cohesive soil have something to do with dam height.The higher the dam is, the slower the slope is.however, gradients of dam slopes made of sand or gravel have little to do with dam height.Generally, there is a road on downstream slope every 10 to 30 meters.When gradients changes, the road will be at the changing line.the road width is determined by its purposes, but never less than 1.5 to 2.0 meters.drainage ditches are built on road for collecting rainwater, resisting wash, observing, repairing, and traffic.壩坡
土石壩壩坡對壩的穩定和工程有著直接的影響,主要取決于壩型、壩高、壩的等級、壩體及壩基的材料性質、所承受的荷載、施工和運用條件等因素。一般先參照已建工程的實踐經驗或用近似方法初步擬定壩坡,然后進行穩定計算、確定合理的壩體斷面。對碾壓式土壩砂、壤土類壩坡,其平均坡度一般在1:2.0~1:4.0左右。當壩基較為軟弱時還需適當放緩。
在擬定壩坡時,應考慮到上游壩坡長期浸泡于水中,土的抗剪強度降低。所以當采用相同土料時壩的上游坡比下流坡要緩;在一般情況下土質斜墻壩的上游坡比心墻壩緩,而下游坡則可比心墻壩陡些;砂壤土、壤土的均質壩坡比砂或砂礫料的壩坡緩些;粘性土均質壩的壩坡與壩高有一定關系,其高度越大,壩坡越緩。砂或砂料壩體的壩坡與壩高的關系則很小。一般壩的下游坡每隔10至30米設置一條馬道。當壩的坡度自上到下有變化時,馬道則設在變坡處。馬道的寬度視其用途而定,但其最小寬度不得小于1.5到2.0米。馬道上設置排水溝以匯集雨水防止沖刷,還可用于觀測、檢修和交通。
English for hydraulic and hydroelectric engineering Slope protection For earth and rock dams, there must be protection upstream and downstream.For upstream, damages caused by wave scouring, damwise stream scouring, ice, and floater must be avoided.For downstream of homogeneous dams, damages caused by rain scouring, storm, ice,stream, animal, swelling, and mud crack must be avoided.If there are rocks, cobbles, and gravels downstream, no more protection is needed.Revetments must be sturdy and durable, able to resist damages caused by various factors.Their undercourse must not be scoured.Materials should be used as local as possible to lower the cost.Simple construction and convenient repairing should be guaranteed.Rocks, stonework, concrete, reinforced concrete, and asphalt concrete are used for building revetments upstream, and stonework, rocks, gravels, and turfs are used for those downstream.Revetments protect the space from dam crest to the line a certain distance, normally 2.5m, under the minimum water level of the dam upstream.For those downstream, they protect the space from dam crest to draining prism or to dam heel in event of no prism.護坡
土石壩的上、下游壩面一般都要設置護坡。上游護坡的作用是為防止波浪淘刷、冰層和漂浮物的損害、順壩水流沖刷等危害;均質壩下游護坡的作用是防止雨水沖刷,風浪、冰層和水流作用,動物、凍脹干裂等對壩坡的破壞。如下游坡由堆石、卵石、碎石砌成,可不設護坡。對上下游護坡的要求是堅固耐久,能抵抗各種因素的破壞作用,并保證底層不受淘刷。盡可能就地取材,以降低造價。施工簡單,維修方便。上游護坡的型式有:堆石護坡、砌石護坡、混凝土或鋼筋混凝土護坡、瀝青混凝土護坡;下游護坡的型式有:砌石、堆石、碎石和草皮護坡。護坡覆蓋的范圍,上游由壩頂護至水庫最低水位以下一定距離,一般在最低水位以下2.5米。下游面則由壩頂護至排水棱體,無排水棱體時則護至壩腳。
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
English for hydraulic and hydroelectric engineering
第二篇:專業英語論文翻譯
A Parallelization Cost Model for GPU
GPU并行成本模型 2009137127 周幼蘭
Abstract-Using GPU for general computing has become an important research direction in high performance computing technology.However, this is not a lossless optimization method.Due to the impact of device initialization cost, data transmission delay, specific characteristics of programs, and other factors, the general computing on GPU may not always achieve the desired speedup, and sometimes results in program execution performance degradation.On the basis of in-depth analysis of GPU internal processing mechanisms, the main factors affecting GPU implementation performance are pointed out, and a parallel cost model for GPU based on static program analysis is proposed to provide judgement basis for using GPU in general computing.摘要:在高性能計算技術領域,使用GPU執行通用計算已成為一個重要的研究方向。但它并不是一種無損優化方法。由于受設備初始化成本、數據傳輸延遲、程序本身特征和一些其他因素的影響,基于GUP的通用計算不可能總是達到預期的加速,有時還會導致程序執行性能下降。在對GPU內部處理機制進行深度分析的基礎上,得到影響GPU執行性能的主要因素,且得出基于靜態程序分析的GPU并行成本模型為GPU在通用計算中的使用提供了判斷依據的結論。
I.INTRODUCTION Graphics processing Unit(GPU)has developed at a speed much faster than the Moore’s Law in recent years, not only improving image processing, virtual reality, computer simulation, and the development of related applications, but also providing a good running platform for general-purpose computing using GPU beyond graphic processing.The application of GPU in general-purpose computing makes a series of new challenges faced by the development of the high performance computing technology.Currently, in order to reduce the programming complexity of GPU in general-purpose computing, many GPU manufacturers and research institutions proposed a number of programming languages and programming models close to traditional programming methods, but different styles, such as Brook+[1], CUDA[2] and OpenCL[3], etc.However, as GPU has its own specific characteristic of hardware architecture and development, programmers must have a high level of expertise.Using GPU for general-purpose computing, the increased performance achieved in large part depends on the hardware knowledge and programming skills of programmers.At present, the most studies for the GPU’s parallelism both at home and abroad directly rewrite and transplant programs on the basis of original serial programs.Because software programmers often lack a deep understanding of the hardware platform and have no corresponding capability of programming hardware programs, program transplantation lead to the increased effects achieved of all kinds of applications accelerating general-purpose computing using GPU have obvious difference [4-6].Program performance analysis technology as a basic method of understanding program behavior, plays an important role for comparing the performance difference between different program implementation, identifying performance bottlenecks of programs, and understanding the hardware resource utilization, and is the important part of development and optimization of high
performance computing programs [7].How to take advantage of program performance analysis technology and combine the architecture characteristics of CPU and GPU to guide the planning and optimization of parallel programs so that a variety of computing resources of CPU and GPU are fully utilized is a problem worthy of study using GPU in general-purpose computing at present.簡介:
近幾年來,計算機圖形處理器(GPU)比摩爾定律發展得更迅猛,這種發展不僅體現在改善圖形處理、虛擬現實、計算機模擬以及相關運用方面,還體現在為使用GPU作圖形以外處理的通用計算提供了良好的運行平臺。
GPU在通用計算方面的運用面臨著高性能計算技術發展的一系列新挑戰。目前,為了減少通用計算中GPU編程復雜性,許多GPU制造商和研究機構提出了一系列編程語言和編程模式,這些編程模式類似于傳統德編程方法,但是具有不同的編程風格,例如Brook++、CUDA以及OpenCL等等。然而,當GPU擁有自己獨特的硬件結構和發展特征時,與此同時程序員必須擁有較高水平的專業技能。通用計算中使用GPU來提高性能很大程度上取決于程序員的硬件知識和編程技術。迄今為止,國內外對于GPU的平行性研究大多數是直接寫入和將程序直接植入到原始串行程序基礎上。由于軟件程序員往往對硬件平臺缺乏深層次的了解,并且沒有相應的編寫硬件程序的能力,所以程序植入導致了各種各樣的運用程序的增加效果有著明顯的差異,這些運用程序加速了使用GPU的通用計算。作為一種理解程序行為的基本方法,程序性能分析技術在比較不同程序執行的性能差異、找出程序的性能瓶頸和了解硬件資源的利用率方面扮演著重要角色,而且它還是高性能計算程序的重要組成部分。如何利用程序性能分析技術以及如何結合CPU和GPU的體系特征來引導平行程序的規劃和優化以至CPU和GPU的大量計算資源得到充分利用,是目前GPU在通用計算方面一個值得探討的問題。
V.CONCLUSION There are a number of studies on the applications related to using GPU in general-purpose computing.The most researches focus on using GPU to improve the execution performance of applications.However, how to measure the costs of GPU at runtime is less discussed.From the perspective of GPU’s internal operation mechanism, analyze the key factors affecting the GPU implementation performance, and propose a cost test algorithm based on static program analysis.The results obtained by experiments show that the algorithm proposed can estimate relatively accurate GPU execution performance, and thus provide a useful reference for transplantation of traditional high performance computing to GPU.結論:
與使用GPU作通用計算相關運用的研究實例比比皆是,且大多數研究將使用GPU來提高運用程序的執行性能為研究中心,但是至于怎樣衡量GPU運行時的成本卻很少有人提及。本論文從GPU內部運行機制出發,分析影響GPU執行性能的主要因素,提出基于靜態程序分析的成本測試算法。實驗所得結果說明所提算法能夠相對精確地評估GPU執行性能從而為傳統的高性能計算的在GPU中的移植提供了一個實用性的參考。
Comment: Cost model has been widely used in the computer field as a way to evaluate whether a program is excellent or not.And quite a number of researchers in computer field has proposed various kinds of cost models for GPU, of which most are under certain conditions.But this paper give us a new perception of cost model for GPU in general-purpose computing.The parallelization cost model for GPU can be generally applied for many application areas.The authors attempt to estimate the cost comprehensively.Actually they take the GPU initialization cost, transmission of data cost as well as the program execution cost into consideration.Each aspect use a special algorithm to calculate the cost.And the cost is measured by the time of each aspect.In this paper ,we can get through the authors’ idea very well ,because they are well organized in form and shown clearly in graphs, charts as well as in equations.The parallelization cost model is more accurate, flexible and portable than models of the past.So we should learn the method they study a topic.That is to consider a question in a broad perspective.And if we keep thinking in this way ,our ability of doing scientific research will be greatly improved.At the same time, we should keep close watch on the field of GPU.As it is such an important processor that it is used widely used on modern computers.It is even considered the core graphics processor of computers.And it develops faster nowadays as the need rises.
第三篇:專業英語論文翻譯
嵌入式系統研究
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嵌入式系統研究
1前言
智能軟件Agent是能夠為用戶執行特定的任務、具有一定程度的智能、能夠自主的執行部分任務并以一種合適的方式和環境相互作用的軟件程序。Agent 有自主性、響應性、學習能力和社會性等特性。這使得它適合在高度動態的環境下做出及時的響應。
嵌入式技術和新一代移動通訊網絡的發展使得嵌入式智能設備大量的涌現。這些設備的大都具有嵌入式操作系統的支持, 并運行著越來越豐富的應用程序。如何對這些應用程序進行測試,就成為一個需要研究的課題。本文將Agent技術引入嵌入式智能設備的測試中,使用目標設備Agent, 測試控制Agent, 網絡環境Agent分別模擬和處理測試設備,測試工程師和測試環境的復雜性,利用Agent自身具有的特點,提出了一種有效的自動化測試的方法。
2相關的研究及本文的思路
Agent 所具有的自主性、響應性、學習能力和社會性等特性,使得它很適合處理復雜測試系統中的問題。將Agent技術應用于測試領域已經有一些相關的研究,下面是具體的介紹。
Jeongeun Choi 和 Byoungju Choi [1]提出了一個基于Agent技術的測試工具,它通過使用用戶接口Agent來處理和測試者的交互,使用測試用例選擇Agent來進行測試用例的選擇,并使用回歸測試Agent進行回歸測試,從而很好的實現了自動化的軟件測試。但是他們提出的測試用例選擇技術僅能在大量已有的測試用例中選擇最佳的用例,不能減少編寫測試用例本身的復雜性。
另外一些研究將Agent 技術應用到了某一領域的測試中。Yu Qi、David Hung 和 Eric Wong [3] 提出了一個基于Agent 技術的Web 應用程序測試方法。專業英語期末考查
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他們使用Agent技術降低了網絡應用測試的復雜性。他們的方法不僅僅適用于Web應用程序的測試,也適合于嵌入式智能設備的測試。
在實際測試過程中,測試人員很大的一項任務仍然是編寫各種測試用例,要真正的提高測試效率,就要提高測試腳本的通用性,減少測試腳本的變化[2] [4]。常見的嵌入式智能設備測試工具(比如TestQuest)使用圖像比對來判斷目標設備的狀態, 這種方法雖然實現了非侵入性的測試,但是存在兩個問題,圖片的抓取和傳送消耗了大量測試資源,不同手機的用戶界面風格變化很大,這使得測試腳本在用來進行新設備的測試時需要對腳本進行維護.然而,實際的設備中,當重要的事件發生時,系統會產生敏感事件來激勵相關模塊進行處理.如果能夠在測試過程中捕獲這些敏感事件,就能更加高效的進行測試.并且,只要操作系統相同,敏感事件的捕獲方式也是一樣,測試用例不會因為界面的變化而變化。本文用目標設備Agent抽象和捕獲測試過程中的敏感事件,并將敏感事件發送給測試控制Agent。而測試控制Agent收到敏感事件后,根據自己的知識,采取相應的動作的機制(如異常處理,重新調度測試等)加以處理。這正好可以作為Agent的推理規則,用Agent的智能性來屏蔽測試過程的復雜性。此外,考慮到目標設備處于復雜的網絡環境中,我們利用網絡環境Agent來控制目標設備所處的網絡信號,從而實現對設備所處網絡環境的控制?;贏gent的測試系統
3.1 總體結構
測試系統的最終目標是實現一個移動數字終端的自動化測試平臺,能夠對移動數字終端上的系統軟件和應用層軟件建立模塊化、可重用的測試腳本庫,提高各種黑盒測試的效率,自動化測試結果的生成,并實現測試結果的回放。
如圖1所示:測試平臺分為四層,包括用戶接口層,測試控制層,通訊層和設備Agent層。其中,過程監控模塊,測試環境控制模塊和設備Agent層采用Agent的思想進行設計,以更好的支持嵌入式設備的測試。
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用戶接口層測試管理與配置腳本編輯器虛擬手機測試控制層測試結果驗證測試資源庫測試腳步執行測試環境控制測試過程監控Agent通訊層設 備agent層Synblan Agent藍牙 GPRS 3G AT視窗的移動Agent定制AgentAT 接口
圖1 測試系統的整體架構
3.2 系統基本執行流程
測試過程是對真實用戶使用手機時“輸入-反饋”模型的一個模擬。系統的基本的使用用例如下,首先用戶通過腳本編輯器或者虛擬手機創建測試腳本并進行基本的配置,然后過程監控模塊調度腳本開始執行,當腳本解釋器解釋執行腳本語句時,腳本解釋器通常使用通訊模塊向手機發送模擬按鍵,然腳本解釋器進入等待狀態,目標設備Agent從通訊模塊得到按鍵,執行按鍵動作,截取屏幕并返回給測試控制Agent,或者如果手機有敏感世事件的發生(如來電,短信,異常等)也會反饋給測試控制Agent,測試控制Agent接到數據,再次激勵腳本運行,并同時將測試結果輸入存入測試資源庫。腳本繼續運行下面的語句,直到運行結束。3.3 目標設備Agent
目標設備Agent駐留在被測試的智能設備中,實現對目標設備的建模。本系統中它接收從PC機中接收到的控制命令,然后在智能設備中進行相應的操作,包括模擬鍵盤事件,截取屏幕并返回給PC,以及根據知識庫中的配置的測試目標,通過推理,有所選擇的將必需的狀態信息主動通知測試宿主機。3.3.1設備Agent 依賴的決策規則
系統事件報告決策規則(SERD-RULE)這個決策規則決定設備Agent在獲取到狀態信息時,是否將狀態信息反饋給上層系統。
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異常處理規則(EM-RULE)
這個決策規則決定了當Agent發現測試中出現異常,要采取的處理方式。3.3.2 Agent 屬性
目標設備Agent具有下面的屬性: ⑴ 自主性
目標設備Agent使得測試用戶無需關注設備的細節,它是設備功能和狀態的一個很好的抽象,通過目標代理Agent,上層測試框架只需要執行相應的虛擬操作,則目標設備Agent會自動將這些虛擬操作映射為對手機的實際操作,并且手機的響應和其它狀態也能夠自動的反饋給客戶,這使得上層測試和底層的設備具體操作無關。
⑵ 智能性
當目標設備Agent獲取到一個變化的被測系統狀態或信息時,它會根據推理規則,僅僅把和本次目標相關的信息發送給測試控制Agent。目標設備Agent還能夠根據異常處理規則,合理的處理測試中出現的異常。3.4
測試控制 Agent
測試控制Agent 實現了對測試過程的建模。它主要實現三個目標: ⑴ 在測試過程中,對測試人員感興趣的事件進行捕獲,當這些敏感事件發生后,系統立刻執行預定義的動作,并為測試提供準確和詳盡的日志。
⑵ 通過和腳本解釋器交互,實現異步的事件通知和交互測試用例的執行。⑶ 處理測試過程中的異常,使得測試過程可以自我修復,進而多個腳本能夠按照預先的調度正常運行.3.4.1測試控制Agent的決策規則
⑴ 事件-條件-行動規則(ECA-RULE)
這是測試控制Agent所依據的核心規則,它定義了某個測試所關心的事件,并根據比對條件,采取相應的動作。
⑵ 異常處理規則(EM-RULE)
測試控制Agent也遵守異常處理規則,它能夠檢測測試過程中發生的異常事件,并執行相應的解決方案,使得測試能夠順利的進行。
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3.4.2測試控制Agent 的屬性
⑴自主性
自主性使得測試人員無需過分關注測試的細節,測試人員僅僅需要選擇測試目標,測試控制Agent就能根據知識庫中的信息,自動生成ECA規則表,并在腳本運行時,按照ECA規則,捕捉敏感的事件并執行相應的操作。
⑵智能性
測試控制Agent能夠根據用戶選擇的測試目標,自動生成ECA規則表,并根據ECA規則,進行推理并采取相應的動作。測試控制Agent還能根據異常處理規則來處理測試過程中發身的異常,保障測試過程的自動,平穩進行。3.5 網絡環境Agent 網絡環境Agent 實現了對網絡環境的模擬和控制。為了測試手機的射頻性能,通常使用基站模擬系統來提供設備所處的無線網絡環境,并且利用編程接口,通過軟件對設備的環境進行控制,使得復雜網絡環境下對目標設備的測試成為可能。系統評估
為了評價本系統的有效性,我們設計了一個比較實驗。試驗在信息產業部泰爾實驗室真實的測試項目中進行。我們將測試工程師分為兩組,第一組使用本文的系統MobileTest進行測試,第二組使用業界著名的TestQuest Pro 進行測試。測試的依據是中國通訊行業標準的數字移動臺測試部分。測試的內容是根據這兩個系統各自已經建立好的回歸測試用例對新的智能手機進行回歸測試,從而比較這兩個測試工具的測試效率和腳本的可維護性。
實驗度量了兩個工具在測試不同種類的測試用例時,自動化執行的用例所占的百分比。從表中可見,雖然TestQuest 在功能測試上有更高的自動化率,在壓力測試,多狀態測試,多任務測試,臨界測試和總計中,MobileTest有更好的測試覆蓋率。這是因為在后四種測試中,測試用例需要不斷追蹤系統的狀態,使用圖片比對機制的TestQuest 很難完成這些工作,而MobileTest 卻能使用Agent返回的敏感事件來進行處理。此外,MobileTest 完成測試任務的時間時15天,比TestQuest 的測試效率要高。
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5總結
本文提出了一個基于Agent技術的嵌入式智能設備的測試方法,它用Agent技術對嵌入式智能設備測試過程中的被測試設備,測試者和網絡環境進行模擬和控制,很好的屏蔽了嵌入式智能設備的復雜性,提高了測試的效率和腳本的可重用性。將來的研究工作中,我們會進一步拓展整個測試系統,使之能夠支持整個測試的生命周期。
本文作者的創新點:本文將軟件Agent技術引入到嵌入式智能設備的自動化測試中,利用Agent的特性,很好的屏蔽了嵌入式智能設備測試中,測試者,待測設備,網絡環境的復雜性,提高了自動化測試的效率。
來源于:《 Journal of Electronic Science and Technology》
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附:英文原文
Embedded system research 1 Introduction
Intelligent Software Agent is the ability to perform specific tasks for the user, with a certain degree of intelligence, able to perform some tasks and autonomy in a proper manner and environment interactions software programs.Agent has autonomy, responsiveness, learning and social and other characteristics.This makes it suitable for highly dynamic environment to make a timely response.Embedded technology and the development of new generation mobile communication networks makes the emergence of a large number of embedded intelligent devices.Most of these devices with embedded operating system support, and run an increasingly rich applications.How to test for these applications to be a need to study.This article Intelligent Agent technology into embedded devices test, using the target device Agent, test control Agent, Network Agent and treatment were simulated test equipment, test engineers and test complexity of the environment, the use of Agent has its own characteristics, proposed An effective automated testing.2 Related research and ideas of this article
Agent possess autonomy, responsiveness, learning and social and other features, makes it very suitable for handling complex problems in the test system.Agent technology in the test area will already have some relevant research, the following is a specific description.Jeongeun Choi and Byoungju Choi [1] proposed a testing tool based on Agent technology, which through the use of Agent to handle user interface and test those interactions, the use of Agent to carry out the test case test case selection choices, and use the Agent for regression testing regression testing, so a good automated software testing.But they can only be made in a large number of test selection techniques select test cases has been the best use cases, write test cases can not reduce its complexity.專業英語期末考查
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Other studies will Agent technology applied to a field test.Yu Qi, David Hung and Eric Wong [3] proposed a Web-based Agent technology application testing methods.Agent technology to reduce their use of the network application testing complexity.Their method not only for Web application testing, but also for the testing of embedded intelligent devices.In the actual testing process, testers great task is still the preparation of various test cases, to really improve test efficiency, we must improve the general test scripts, reduce test script changes [2] [4].Common test tools for embedded smart devices(such as TestQuest)using image comparison to determine the status of the target device, although this method to achieve a non-invasive test, but there are two problems, the image capture and transmission consumes a lot of test resources, the different style of phone's user interface has changed dramatically, which makes the test script used for testing new equipment required for maintenance of the script.However, the actual device, when an important event occurs, the system will generate sensitive events to encourage the relevant module for processing.If during the test capture these sensitive matters, will be able to test more efficient.And, as long as the operating system the same sensitive way to capture the same event, the interface test cases will not change.In this paper, the abstract and the Agent target device during the test capture of sensitive events and control of sensitive events are sent to test Agent.Agent receives the test control sensitive incident, according to their knowledge, take appropriate action mechanisms(such as exception handling, re-scheduling the test, etc.)to be addressed.This is precisely the inference rules as Agent, with the intelligence of Agent to shield the complexity of the testing process.In addition, given the target device is a complex network environment, we use the Internet Agent to control the target device environment in which the network signal, enabling the network environment in which the control device.3 Agent-Based Test System 3.1 The overall structure
Test system is to achieve the ultimate goal of a mobile digital terminal's automated testing platforms to the mobile digital terminal on the system software and 專業英語期末考查
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application layer software build modular, reusable test script library, to improve the efficiency of various black box testing, automation the generation of test results and test results to achieve playback.Figure 1: Test platform divided into four layers, including user interface layer, the test control layer, communication layer and the equipment Agent layer.Among them, the process monitoring module, test equipment, environmental control module and the use of Agent Agent layer design ideas to better support embedded devices testing.The user interface layerTesting management and configurationScript editorVirtual cell phone
TestControl layer Test results show Testing steps executiontestrepository Test environment control Testing process monitoring AgentCommunications layer Set for Agent layerBluetooth GPRS 3G ATSynblan Agent Windows mobile AgentCustomization AgentAT 接口Figure 1 The overall architecture test system 3.2 The basic system implementation process
Testing process is a real cell phone users "inputcondition-action rules(ECA-RULE)
Control Agent This is a test based on the core rules, which defines a test case of interest, and according to comparison conditions, take appropriate action.⑵ exception handling rules(EM-RULE)
Test Control Agent also comply with exception handling rules, which occurred during the test can detect abnormal events and to implement appropriate solutions to enable testing to proceed smoothly.3.4.2 Test Control Agent's Properties ⑴ autonomy
Autonomy to make the tester without too much attention to the details of the test, testers just need to select the test objectives, test control Agent information can be based on the knowledge base, automatically generate ECA rules table, and run the script, according to ECA rules to capture sensitive event and perform the appropriate action.⑵ intelligence
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Test Control Agent to the test objectives based on user selection, automatically generates ECA rules table, and according to ECA rules, reasoning and take appropriate action.Test Control Agent can exception handling rules based on the testing process to deal with abnormal body fat to protect the testing process automatically and smoothly.3.5 Agent Network
Network Agent implements the network environment simulation and control.In order to test the phone's RF performance, usually the base station simulator to provide a device in which the wireless network environment, and use programming interface, the software environment to control the device, making the complex network environment, the target device under test as possible.4 System Evaluation
In order to evaluate the effectiveness of the system, we designed a comparative experiment.Tell testing laboratory in the Ministry of Information Industry of the test project for real.We will test engineers divided into two groups, the first group to use this system MobileTest test, the second group uses the industry's leading TestQuest Pro test.Test is based on the number of China's telecommunications industry standard part of mobile station testing.Test content is based on both systems return to their already established on the new test cases for regression testing of smart phones to compare these two test tools, test efficiency and maintainability of the script.Table 1 regression test results:
Two experimental tools to measure different types of test cases in the test, the automated implementation of the percentage of use cases.Can be seen from the table, although the functional testing TestQuest higher automation rates, the stress test, multi-state testing, multi-tasking tests, critical test, and the total, MobileTest better test coverage.This is because after the four tests, the test case need to constantly track the system state, the use of pictures than on the mechanism of TestQuest difficult to accomplish these tasks, and MobileTest able to use the Agent to return to the treatment of sensitive events.In addition, MobileTest time to complete the test task 15 days, TestQuest's test efficiency than higher.專業英語期末考查
第13頁 Conclusions
This paper presents a technique based on embedded intelligent devices Agent test method, which uses embedded intelligent Agent technology equipment is tested in test equipment, test and simulate and control the network environment, a good shielding of the embedded the complexity of smart devices to improve the test efficiency and reusability of the script.Future research work, we will further develop the test system so that it can support the whole testing life cycle.The innovation of the author: This article introduces the software Agent technology to automate testing of embedded intelligent devices, the use of Agent's features, nice screen test for embedded smart devices, testers, test device, the complexity of the network environment and increase the efficiency of automated testing.From:《 Journal of Electronic Science and Technology》
第四篇:專業英語論文翻譯
MET基因復制數量的增加賦予單克隆抵抗體抗MET的能力并且建立藥物依賴性
關鍵詞:MET,MV-NV30單克隆抗體,酪氨酸激酶抑制劑,抗性,藥物依賴性 【摘要】:被MEI原癌基因編碼的酪氨酸激酶受體領導了具體抑制劑的發展并在癌癥中起很重要的作用,其中現在一些正處于前進的臨床試驗階段就以前的經驗表明對大多數靶向治療最主要的限制是抗性的出現。在對MET單克隆抗體抗性和抗體對化學抑制劑旁路抗性(反之亦然)一無所知時,酪氨酸激酶抑制劑對MET的抗性機制就已經被提出。EBC1型肺癌細胞是MET基因擴增的結果,并且這種細胞對MET抑制劑非常敏感,包括MET單克隆抗體的單機形式在內。我們培養生成抵抗抗體的細胞發現這種抗性是由于MET基因大量復制擴增和它的受體顯著表達而來。這種過度表達可以使單克隆抗體的“脫落”活動達到飽和,并且能夠防止表面的MET受體的有效的下調和抑制劑的活化作用。值得注意的是MV-DN30抗體的抗性細胞是MET耐受細胞對MET酪氨酸激酶抑制劑也很敏感。除此之外,抗體抗性細胞還具有藥物依賴性,MV-DN30的去處導致它們死亡是由于它們的過度信號表達。在實驗中,對MET酪氨酸激酶抑制劑存在抗性的細胞仍然對MV-DN30抗體的作用敏感。結果表明一種不連續的通過抗體和化學激酶抑制劑聯合治療可能會使靶向治療的臨床反應和對MET抗體治療旁路的抗性增加。
縮略語:MV-DN30--單價DN30,TKEs—酪氨酸激酶抑制劑,HGF—肝細胞生長因子,MAPK—有絲分裂原活化蛋白激酶 1.簡介
可以抑制一個特定的目標分子化合物的靶向治療法開辟了治療癌癥的新道路。與主要殺死擴散細胞為主的傳統化療不同的是靶向藥物對腫瘤細胞采取一種更具體的治療方式。靶向治療依賴于“癌基因沉癮”的概念。這就意味著單個基因的抑制或死亡是由于它們的沉癮,或者至少抑制它們的生長(溫斯坦,2002)。臨床試驗中的特定抑制劑的發展給腫瘤細胞的“Achille’s heel”的識別提供支持(溫斯坦和喬,2006)。
盡管靶向治療在一部分癌癥患者中取得了較優異的效果,還有重要的一點就是部分癌癥病人對藥物的選擇表達沒有起到治療作用(原發性),除此之外,幾乎總是一開始患者反應變成后來對治療的抵抗和復發(繼發性)。因此,最關鍵的就是要發現對治療抵抗的機制并且找到繞過它們的方法。
癌基因和人類癌癥密切相關,酪氨酸激酶起著決定性作用。這個觀察發現許多腫瘤沉溺其中使得蛋白激酶成為了治療癌癥的理想目標(巴塞爾加,2006;Gschwind等人,2004)。在臨床診斷中主要使用一種較小的激酶抑制劑和單克隆抗體來抑制酪氨酸激酶。酪氨酸激酶抑制劑是一種可以抑制靶蛋白酶活性的小分子物質。它們能有效地瞄準膜結合位點和細胞內的激酶并且很容易在體內擴散。單克隆抗體已被廣泛用于臨床并取得了可觀的成果。這些分子的優點在于它們具有很高的特異性。在癌癥治療中的可以抗癌的RTKs單克隆抗體已經被批準在乳腺癌和結腸癌中使用(分別針對HER2和表皮生長因子受體)并可作為抗血管增生的藥物(針對血管內皮生長因子受體)。除此之外,很多針對于其他目標的單克隆抗體正處與發展和試驗階段。最近,一種作為癌癥治療目標的RTK受到關注,這種RTK是由致癌基因編碼的在肝細胞生長因子上的酪氨酸激酶受體。在和肝細胞生長因子結合后,MET活化并啟動一個復雜的生化程序,這個過程被稱作“浸潤性上長”。在腫瘤組織中,浸潤性生長的增進可以迫使腫瘤細胞從腫瘤組織中分解下來侵蝕基底膜,滲入基質中,甚至定居于新的組織中來實現轉移。很多研究結果表明MET在人類的許多腫瘤中具有活性,并且它與對直接激酶療法的持續抗性密切相關。除此之外,還表明細胞顯示大量復制(超過8張)和隨之而來的過度表達和獨立配體的激活都是沉溺于這種致癌基因和抗MET藥物的應答中。在前期設置得到的基本結果,幾種特定的多目標的酪氨酸激酶抑制劑和直接針對于MET或者HGF的抗體已經進入了臨床試驗階段。在活體和動物模型進行的研究已經表明用TKIs長期治療會導致機體的治療耐受性。對MET TKIs的抗性可能是由于一些機制,比如MET基因擴增,過度表達,MET點突變,MET平行路徑的激活和KRAS基因的擴增機制。然而,關于對MET的單克隆抗體的再次具有抗性一無所知。
我們以前報道過主要針對細胞外的部分MET的抑制性單克隆抗體的研究進展。它的誘導、再結合、達到MET脫落閾值的能力使其有抑制活性,剩余的跨膜片段通過蛋白酶體降解途徑處理掉。因此,DN-30結合到MET后的結果是使其變成可溶性的誘餌MET并且蛋白水解酶會講解MET激酶。這促進了MET介導的生物活性的抑制作用。設計了這樣一個過程就是因為DN-30的結合使得MET激酶部分活化并且導致抗體介導的受體同源二聚體化和單價Fab片段失去競爭活性的一個過程。
在這個研究中我們表明了不斷用MV-DN30來治療沉癮癌細胞會使其具有抗性的原因是MET基因的大量復制和MET的過度表達超過了MV-DN30對其有效下調并使其失去活性的的能力。值得注意的是,MV-DN30抗性細胞還會一直對MET TKIs產生耐受性和敏感性。有趣的是,它們獲得了藥物耐受性,當受到MV-DN30的驅除致死它們的是過多的信號表達。我們還表明對MET TKIs 有抗性的細胞也對MV-DN30敏感,所以,MV-DN30和MET TKIs 對腫瘤細胞的作用是相互促進的。2.材料與方法 2.1.細胞和試劑
EBC1 細胞從一個患有轉移皮膚腫瘤的病人取得,這個患者還患有肺鱗狀細胞癌,病例是從日本癌癥資料庫購買得到。GTL16 是一種實驗室里的克隆胃癌細胞系。HEK-293T細胞系分離于人類胚胎時期的腎,A549細胞系來源于肺癌,都是從ATCC購買來培養的。對MV-DN30有抗性的EBC1細胞可以通過一個逐步的方法培養得到,由Sigma Tau R&D 提供的通過暴露親代細胞方法來增加抗MET單價單克隆抗體的濃度。親代細胞用10 mg/ml 的MV-DN30治療約一個月,直到生成的R10細胞開始產生抗性為止,R10抗性細胞又用逐步增加濃度的MV-DN30治療。所有的抗體耐受細胞培養在存在MV-DN30并且可以使它們產生耐受性的條件下。大約兩個月可以分離到R20抗體抗性細胞,四個月可以分離到R80抗體耐受細胞。EBC1 and GTL16 細胞對MET TKIs PHA-665752(EBC1 RPHA 50 nM and GTL16 RPHA 150 nM)都有耐受性,并且向描述的那樣培養可以一直保持PHA-665752的存在。該細胞系的遺傳身份通過一個短的串珠狀重復序列(STR)識別,這段序列在2013年7月再次重復出現。We 我們利用下面的小分子:ATP競爭行MET TKIs PHA-665752(Tocris Bioscience)and JNJ-38877605(John-son & Johnson)和p38MAP激酶抑制劑SB203580(Merck).2.2.mRNA和基因組DNA的分析
用Trizol 試劑提取得到的RNA被檢測到利用多文士病毒的逆轉錄酶和隨機引物合成,cDNA可以用實時的利用電源帶動的綠色PCR混合的PCR 技術來實現擴增,根據制造商的說明下面的MET和ACTIN特異性引物要用到: hMET ex 19 Fw: 50-AGTTTACCACCAAGTCAGATGTGT-30;hMET ex 20 Rw: 50-GGGCTCCTCTTGTCATCAGC-3;hACTIN Fw: 50-GGAGGAGCTGGAAGCAGCC-30;hACTIN Rw: 50-GCTGTGCTACGTCGCCCTG-30.根據制造商的說明用實時PCR技術來分析用純化的DNA基因組迷你試劑盒分析從細胞中提取到的基因組DNA,這種技術是用 TaqMan基因表達的主要結構和TaqMan探針MET基因和RNaseP控制基因的實時定量PCR分析。MET的mRNA的成倍增加和EBC1中MET基因的大量復制以及MV-DN30抗性細胞歸一化然后被認可。2.3.蛋白印跡分析和脈沖追蹤代謝標記
蛋白提取液(40 mg), 細胞上清液(20 ml)。在細胞裂解前2小時把MET TKI JNJ-38877605加入到指定的地方。免疫印跡法使用了以下的初級抗體:the anti-MET Intracellular domain(ICD)(zymed, #370100)from Invitrogen, anti-MET ECD(DL21)obtained as described(Prat et al., 1991), anti-phospho-Tyr1234-Tyr 1235MET(#3126), anti-AKT(#9272), anti-phospho-Ser473AKT(#4060),anti-p44/42MAPK(#9102),anti-phospho-Thr202-Tyr204p44/42MAPK#9101),anti-p38MAPK(#8690),anti-phospho-Thr180-Tyr182-p38 MAPK(#9215), from CellSignaling;anti-vinculin(#V9131)from Sigma and anti-b-actin(#I-19 sc-1616)from Santa Cruz Biotechnology.Secondary IgG HRP-Peroxidase antibodies were from Amersham.脈沖追蹤實驗的1106WT,或MV-DN30抗性的EBC1細胞(R80)都被平鋪在60mm的盤里。R80 細胞保存在有或沒有抗體(80 mg/ml)存在的條件下,而WT細胞要一直保存在有抗體的條件小16小時。然后,這些細胞在不含L-蛋氨酸但有500mmMCIL-甲硫氨酸S35(脈沖)(易標記)的DMEM培養基中處理20分鐘。在這之后,去處放射性標記的培養基,細胞用1ml磷酸鹽緩沖液鹽水洗兩次然后保存在有2mlISCOVE的培養基中,培養基中加入2%FBS,在MV-DN30(80 mg/ml)存在或不存在脈沖3.6和16小時。之后,用免疫沉淀法(IP)在1ml細胞裂解液中進行測定(裂解緩沖液:1% TritonX-100存在下,20 mM Tris-鹽酸,5毫米EDTA,10% V / v甘油,150 mM NaCl補充蛋白磷酸酶抑制劑)通過使用抗Met ICD dq13單克隆抗體,而IP法利用抗Met ECD do24單克隆抗體對細胞培養2毫升上清液進行。細胞裂解液和上清液都在有已知抗體的培養基里培養16個小時,抗鼠IgG抗體預包被瓊脂糖凝膠蛋白珠形成免疫復合物沉淀下來。免疫沉淀物中的蛋白就會被8% SDS-PAGE 分開,然后轉移到3mm的紙上,80度,48小時后蛋白質的放射性就會在投影膜上留下印記。2.4.生長和可行性分析
用于細胞生長和可行性分析的這些細胞被接種在96孔的培養板上,根據制造商的說明用已知藥物在不同時期進行處理然后用細胞滴度發光細胞進行可行性分析。沒經過處理的細胞控制在藥物載體存在的條件下生長。所有的數據進行歸一化到0天的藥物治療。2.5.熒光細胞分析
對結合在EBC1WT,R20,R80細胞質膜上的MET進行免疫熒光著色,這些細胞要提前在有或沒有MV-DN30存在的條件下培養24小時。熒光性的強度可以通過細胞熒光性分析檢測到。用于檢測的細胞要在PBS中用2%FBS洗滌并且在室溫下用抗MET ECD DO24 mAb(100 ng/ml)著色20分鐘。然后在室溫下細胞又在PBS中用2%FBS洗滌就會逐步產生抗鼠IgG-RPE二抗然后用二脒基苯基吲哚作用20分鐘。作為陰性對照,將不含初級抗MET抗體的細胞進行染色。質膜結合的蛋氨酸的熒光強度(AU為單位),通過使用GraphPad Prism軟件繪制為箱形繪圖圖表。
2.6.慢病毒載體轉導
EBC1 WT 細胞能穩定地在兩種不同量的慢性病毒顆粒編碼的MET cDN轉導,包括1mg(METtt)和1.6mg(METttt)的p24病毒抗原,其濃度按說明確定。作為對照,WT細胞用含有空載體病毒顆粒感染。MV-DN30抗性細胞(R20 and R80)只用空載體感染。在感染48小時后接種細胞用于生物化學分析。轉導細胞的可行性分析如先前描述的一樣進行,讓細胞在存在或不存在MV-DN30的條件下上長72小時。如先前所述,MET的蛋白印跡分析和磷酸化的MET蛋白水平和對感染細胞的mRNA的表達水平實時定量PCR分析一樣子細胞感染72小時后進行評估。2.7.藥物協同作用分析
在抗MET抗體MV-DN30和MET TKI JNJ-38877605之間進行藥物協同作用分析是對WT EBC1和接種在96孔板上的GTL16細胞在用藥物治療72小時后的細胞活力的研究。如果使用一個藥品從藥物劑量來說要比混合使用的IC50約高10倍左右,雙重增加濃度可以用于單藥使用和組合使用。評估細胞活力為前面描述的增效作用的藥物效應多種分析研究,采用組合指數(CI)和Chou and Talalay 方法。使用相互排他性假設計算CI值(藥物作用機理的不同,采用compusyn.exe)軟件,可上線的網站:http://compusyn.software.informer.com/,和繪制功能的FA(由這兩種藥物的組合影響系統分數)。CI值< 1表明兩種藥物之間的協同作用。2.8.統計分析
同一個實驗數據用GraphPad Prism軟件進行兩尾t檢驗分析至少有三種生物學具有統計學顯著意義的結果。P值小于0.05被認為是有意義的。3.結果
3.1.MV-DN30耐藥細胞株的建立
EBC1 肺癌細胞是MET沉癮細胞,它能放大MET的擴增、過度表達和活化過程。MET TKIs或者MV-DN30對EBC1細胞里的MET具有強烈的破壞它們生存和上長的能力的作用(圖A~C)。
我們先前培養的EBC1細胞 對不同的YKIs有抗性表明了這種抗性可能是由于MET基因的進一步擴增。為了產生抗MV-DN30的細胞,我們采用逐步暴露EBC1原代細胞不方法來增加抗體的濃度,并且獲得抗不同劑量抗體的細胞系(圖1b;約的分步方法詳見材料和方法部分)。, 進一步的實驗中,我們使用耐20細胞(ebc1 R20)和80(ebc1 R80)毫克/毫升mv-dn30,劑量是分別是前面的約10倍和40倍,然后測這些細胞的抗體IC50(圖1a)。在有MV-DN30存在的抗性細胞的生長速度一直和WT細胞差不多(圖1C)。
正如前面提到的,MV-DN30發揮它的抑制活性是通過誘導MET的結構域蛋白反正溶蛋白裂解,隨后又通過蛋白酶體受體介導受體降解。這種反應減少了細胞表面的MET的大量表達,抑制了MET的活性和受體介導的生物學活性。如圖1D所示,事實上,MV-DN30的治療導致了再EBC1細胞中的MET通過酪氨酸酶的磷酸化消除大量減少。與抗性細胞的生化分析相反的是顯示了在相同劑量抗體存在的情況下,MET也會磷酸化并且在質膜上的大量的MET蛋白明顯高于保存在相同條件下的WT細胞(圖1D,E)。除此,盡管激活的下游目標AKT和MAPK激酶都被保存在有抗體存在的條件下(圖1D)。
所有的數據表明,抗EBC1細胞的MV-DN30并不是通過一種足以消除它的結構的活性的方法來下調MET,而是一種允許它的信號轉導來調節它的結構磷酸化的方法.3.2.抗性細胞中缺乏MV-DN30抑制活性并不是因為它的活性不足
如圖1D,E所示,用MV-DN30處理抗性細胞致使MET大量減少這種減少比處于同等條件下觀察的WT細胞中的減少更明顯。我們想知道在抗性細胞里的抗體受損是否是由于MET的結構域IPT4發生突變引起,這個結構域是它的集合位點,但是我們沒有發現任何突變(數據顯示)。
于是,我們評估了是否是抗性細胞中脫落的MET胞外結構域(ECD)對抗體的反應被抑制了。在相同劑量MV-DN30存在的條件下培養了24小時的抗性細胞和WT細胞的上清液中,抗性細胞上清液中含有更豐富的脫落的ECD(圖2A)。當對去處抗體24小時后的抗性細胞中MET的表達和活化進行評估時,我們觀察到MET總量強烈增加特別是結合在細胞膜上的形式(圖2B和圖1)。對抗性細胞再引入MV-DN30細胞會導致上清液中MET ECD含量更高,與在同樣劑量處理的WT細胞相比,之后細胞內的MET同時減少了并返回到平時觀察的抗性細胞的一半水平(圖2 D)。在脈沖代謝標記實驗中也觀察到了相似的結果:比起WT細胞,抗性細胞合成更多的MET和MV-DN30來促進MET ECD 釋放并大量增加(圖2E)。最后,用更高劑量抗體20 mg/ml(R20)處理EBC1細胞來更好的證明MV-DN30在抗性細胞中是具有活性的。圖2F所示在抗性細胞中隨著MV-DN30劑量是增加減少了大量MET在細胞膜上的表達(圖2A)和磷酸化(圖2B)。
總之,所有的結果表明EBC1細胞的抗性不是因為MV-DN30活性缺乏,而是由于用它的飽和能力來促進了一種高效的MET解離。
圖1-抗MV-DN30的EBC1細胞分子表征。(A)在有MV-DN30的遞增濃度的條件下培養了72小時的EBC1 WT細胞的細胞活力。對未經過處理的細胞(100%)± s.d.的歸一化結果。(B)在指定濃度抗體的條件下培養72小時的EBC1 WT細胞或產生MV-DN30抗性的細胞(R10, R20, R40, R80)。與未經過處理的WT細胞(100%)± s.d歸一化結果。(C)在MV-DN30(20 and 80 mg/ml)存在的條件下生長的EBC1 WT細胞EBC1R20和R80細胞的生長活性。與未經過處理的WT細胞(100%)± s.d歸一化結果(***P < 0.001)。(D)在有指定劑量MV-DN30抗體存在的條件下處理24小時的EBC1WT ,EBC1R20和R80細胞的蛋白印跡。(E)結合MET的在24小時在不存在或存在的血漿膜的熒光強度的箱圖mv-dn30 R20和R80生長EBC1 WT細胞(AU:任意單位)
圖2—細胞耐受性并不是由于失去了對MV-DN30的敏感性。(A)在存在或不存在MV-DN30的環境下培養24小時的EBC1 WTR20和R80細胞的上清液中MET ECD的蛋白印跡。(B)在有或沒有(24小時去除)的EBC1WTR20和R80細胞中的蛋白(頂部)和蛋氨酸的酪氨酸磷酸化蛋白印跡。紐蛋白作為控制基礎(C)在 EBC1 WT, R20 and R80 細胞中有或沒有(24小時去除)MV-DN30的條件下在質膜上結合的MET的熒光強度的箱圖。質膜著色如圖E。(D)在用MV-DN30處理(24h)的EBC1WT R20和R80 細胞中和抗性細胞(圖2 D)中觀察到的MET總蛋白水平和MET ECD 的蛋白印跡.(E)在有或沒有MV-DN30存在下的EBC1WT和R80細胞里的MET(來源細胞裂解液,上面)和MET ECD(來源與細胞上清液,底部)的用脈沖追蹤代謝蛋白標記法的免疫沉淀分析。(F)在遞增MV-DN30濃度的環境下的EBC1(左圖)和R20細胞(右圖)的活性檢測。未經過處理的WT細胞(左圖)或者用20 mg/ml(100%)處理的R20(右圖)統計結果(***P < 0.001, *P < 0.05)。3.3.對MV-DN30的抗性是由于MET的擴增和過度表達
如上圖所示(圖2BeD),MV-DN30抗性細胞表達MET水平比原代細胞更高。我們懷疑這可能是由于增加的啟動子活性或更高的mRNA的可用性,因為你微RNA的負控制微分表達了。在EBC1WT和抗性細胞的熒光素酶檢測結果顯示排除這些可能性(數據未顯示)。
然后我們評估了基因擴增的情況是因為MET大量復制是對激酶抑制劑存在抗性的機制。如圖3所示,EBC1抗性細胞顯示了MET的大量復制(原代細胞的第24代到30代),這大約是二倍體細胞的15倍。當分析MET的mRNA水平時,我們觀察到MET的過度表達是WT細胞的2~3倍,達到了MET正常表達細胞(A549 and HEK-293T)的60~90倍。為了證明這種增加可能是為了維持對MV-DN30的抗性,我們將EBC1WT細胞放在不同量的MET cDNA條件下轉導,通過比較EBC1R20和R80細胞mRNA的表達水平來獲得(圖3)。我們觀察到,MET的mRNA以2~3倍的速度劇增,這與在存在MV-DN30的條件下細胞的活性有關(圖3D)。除此,盡管有MV-DN30的存在MET保持磷酸化,這就解釋了為什么細胞能夠存活增加(圖3E)。
所有實驗結果表明,嗜MET的EBC1細胞變得有抗性是因為MET的進一步擴增和過度表達從而來阻止有效的抗體介導的對MET活性的抑制。圖3
3.4.抗MV-DN30的細胞也是嗜MET細胞并有藥物依賴性
為了證明抗MV-DN30的細胞也是嗜MET細胞,我們用一種小分子的激酶抑制劑JNJ-38877605來處理細胞。如圖4a,b所示,抗MV-DN30的EBC1細胞在有抗體(20 mg/ml for R20 and 80 mg/ml for R80)存在的條件下生長情況顯示了當用MET激酶抑制劑JNJ-38877605(10 nM or 250 nM)處理時,細胞活性的降低和MET磷酸化作用的減弱。和親代EBC1細胞相比,抗性細胞對JNJ-38877605的敏感劑量更低,可能是由于在抗性細胞中MET的蛋白合成和轉運更高效。從抗性細胞的培養基中去除MV-DN30會導致MET的表達增加(圖2B),我們研究了過度表達的生化效應。抗性細胞培養在不存在MV-DN30的條件下,顯示了活性下降(圖4C)。這些細胞的蛋白印跡分析表明,隨著時間的推移逐漸增加了磷酸化(圖4D)。然而,24~48h后,after 24e48 h, p38 MAPK的活化清晰可見證明了通常在細胞凋亡反應之前會有一個細胞應激反應。除此之外,在沒有MV-DN30存在的條件下培養的抗性細胞中的p38 MAPK會受到一種小分子SB203580 的抑制使得細胞活性得以恢復(圖3)。這些數據進一步表明,p38 MAPK信號對于參與藥物依賴是至關重要的.重要的是要記住對于嗜MET細胞抗MET酪氨酸激酶抑制劑的藥物依賴條件和黑色素瘤有獲得性的藥物依賴性已經被證明。為了證明當去除MV-DN30后過多的MET信號使細胞凋亡是正確的,我們用低劑量的MET YKI處理抗性細胞讓其充分減少但不會完全抑制MET活性(圖4)。事實上,如圖4E所示,保存在不含MV-DN30并用 10 nM JNJ-38877605(低于IC50濃度)處理的抗性細胞可以恢復它們的活性,并且這種水平類似于保存在有抗體存在的培養條件下的抗性細胞的活性水平。
總之,這些結果表明,MV-DN30抗性細胞都是嗜MET細胞并且它們的繁殖和生存都有藥物依賴性。圖4
3.5.在嗜MET細胞中MV-DN30和MET TKIs的協同作用
MET-TKIs 和 MV-DN30 都可以有效的抑制EBC1細胞的活性,我們想知道這兩種抗MET化合物是否表現增強或協同作用。單獨或在有非常低劑量的MV-DN30存在的條件下(0.15~2.5毫克/毫升,從10倍以下的IC50開始),我們用逐步增加MET抑制劑JNJ-38877605的方法來處理EBC1 WT細胞。然后我們分析細胞活力和對藥物治療的兩種藥物的組合效應的性質,利用多藥效果分析。如圖5C所示,聯合治療導致的劑量盡可能低為1.25~20 nm jnj-38877605在0.15~2.5毫克/毫升mv-dn30存在活性降低。當在GTL16 WT 胃癌細胞上做這個實驗室會得到相似的結果(圖5D)。如圖5A、B所示,多藥效應分析表明了 EBC1 and GTL16 WT細胞的CI值都小于1,從而表明了JNJ-38877605和 MV-DN30之間有藥物協同作用.所有的這些數據表明用MET TKI和MV-DN30聯合治療可以有效地減少嗜MET細胞的活性,劑量明顯低于單獨一種藥物治療的藥量。圖5
4.討論
臨床效應甚至是最有效的靶向治療都被發展的耐藥性所限制。顯而易見,這種耐藥性機制已經被廣泛研究。從癌細胞和抗酪氨酸激酶抑制劑表明,獲得性耐藥的最常見的機制包括在藥物目標本身的二次突變的患者獲得的數據,激活下游信號轉導或平行的信號轉導通路的激活突變。即使對關于癌癥是怎樣產生耐藥性抗體的了解很少,一些現象提示用抗EGFR 和抗HER2抗體治療的病人體內有耐藥機制的建立。在EGER中的二次突變表明了免疫調節藥物與EGFR的結合受到破壞從而調節了抵抗力。除此之外,最近的研究還證明了EGFR或HER2的信號轉導通路的激活可以分別繞過西妥昔單抗或曲妥單抗的抑制;這些包括EGFR配體水平增加,MET RTK的擴增或過度表達,下游或平行激活信號轉導途徑。
在癌癥治療中MET受體已經變成了最具關注的目標,因為很多研究表明,MET在多種人類腫瘤中具有組成性活性。它的失調可能是由于不同的機制包括過度表達,基因擴增,激活突變和受體介導的刺激自分泌或旁分泌的增加。生殖細胞的激活突變的識別和遺傳型腎乳頭狀癌直接證明了MET和人類腫瘤發生有關的概念。MET的酪氨酸激酶的結構域中激活突變位點已經在散發腫瘤中確定。然而,在人類癌癥中變化頻繁的是轉錄表達的過程,這個過程是由原癌基因激活誘導抑癌基因失活和對特定的為mRNA或缺氧刺激的下調過程。在原發性腫瘤中由基因擴增引起的MET過度表達是少見的,但在肺癌和結腸癌中變得抗靶向其它RTKs治療的情況更頻繁。臨床證據表明癌細胞是沉溺在原癌基因中的細胞,在這種細胞中的MET具有組織性活性并且它們的抑制結果就是使其致瘤性被破壞。然而,用小劑量的激酶抑制劑延長對嗜MET細胞的處理會導致二倍抗性的出現,這種機制可以被維持比如MET擴增或突變,KRAS的擴增或EGFR家族成員的活化。在我們的研究中表明,在嗜MET細胞中對MET特定抗體MV-DN30的抗性獲得是由于MET復制數量的大量增加。這一現象的機理解釋依賴于染色體外的MET復制的動態調節,造成了一種癌癥對治療的適應性程序。MET上調的增加是由于MET基因擴增造成的這種現象并不明顯當抗性細胞培養在有抗體(這種抗體介導了MET的下調)存在的條件下,但是在沒有這種抗體存在的條件卻是很明顯清晰的。我們觀察到蛋白的增加平行下來是METmRNA增加的2~3倍。EBC1 原代細胞的METcDNA的轉導可以達到一個和抗性細胞一樣是表達水平,證明了事實上細胞表達更多的MET可以減少對MV-DN30抑制活性的敏感性。WT EBC1細胞和大多數嗜MET細胞一樣可以表達比正常表達細胞的約30倍多的MET;因此,在抗性細胞中2~3倍的增加可以引起MET水平比那些正常細胞中的MET水平高60~90倍。在缺氧的環境下觀察A549細胞中MET呈3倍增加才能滿足它的生化效應,在抗MV-DN30的EBC1細胞中MET增加可以解釋為什么抗體能夠有效地下調MET。除此,作為抗性細胞識別增加的脫落的MET導致了MET ECD在細胞內的累積,并且脫落的ECD可以和細胞膜上的MV-DND30結合位點結合從而減少抗體的抑制效應。抗性細胞仍然依賴于MEI的信號傳導來增殖和生存,MET可以完全被TKIR抑制從而導致它們的增殖受到抑制。有趣的是,當MET變得非常活躍的時候,可以通過增加在MV-DN30存在下的MET 的表達在這種適宜的有利的環境下來使其對藥物的去除效果減弱。我們的結果和報告是一致的都表明了,正常細胞和腫瘤細胞不僅對信號(即該通路被激活的信號)的質量敏感而且對數量也很敏感(這種量就是怎樣激活通路)。信號過量可導致細胞應激(在我們的情況下,通過p38 MAPK活化)導致細胞死亡。事實上,在抗體缺乏,低劑量的遇到了TKI治療耐藥細胞(抑制野生型細胞活力)增加了他們的活力,減少了信號的水平細胞持續強度的可能。Das Thakur做了一個類似的觀察,這個人證明了人類黑色素瘤移植提供的抗藥性,藥物的去除使耐藥腫瘤的腫瘤消退是由于依賴BRAT信號過量。有趣的是,他還表明不連續的藥物劑量,運用耐藥細胞在沒有藥物環境下的劣勢來防止耐藥性的發作。這在嗜MET細胞中也被證明是正確的,無論是抗MV-DN30還是抗TKIs的EBC1細胞都表現出藥物依賴性并且去除藥物會致死細胞。因此,可以想象,為了防止由于癌基因過量用藥而產生抗性,間斷性用藥的機制可能會比連續用藥更有效。
此外,我們表明,抗體治療是活躍的細胞提供的抗酪氨酸激酶抑制劑,相反,TKI治療耐mv-dn30細胞有效。這并不奇怪,因為這兩種類型的抗性細胞都是嗜MET細胞,因此,依賴MET的信號減少導致了它們的死亡。這種發現在臨床上受到關注,因為它表明了用抗MET的抗體治療病人可能是沒用的,病人的對TKIs的抗性是由于MET表達的增加或者是它們的毒性限制了TKI的劑量。另一個處于我們的觀察的結果是MV-DN30和MET-TKIs之間的協同作用。值得注意的是,盡管是幾個實驗,在用MET TKI和MV-DN30治療時我們并沒能過培養出抗性細胞。這些觀察的臨床意義提出了一點就是兩種藥物劑量的減少的可能性,結果它們又不利影響當需要保持治療效應時有可能會降低或延遲。總的來說,在事實的角度評估我們的結果就是它們表明了兩種可能會克服或防止對METmAbs抗性的治療策略:(i)一種就是用抗MET的mAb加上MET TKI的聯合治療(ii)利用抗性細胞的藥物依賴性的定期間斷性的節律治療。
第五篇:土木工程專業英語論文翻譯
建筑材料
鋼的最嚴重缺點是它容易被氧化而需要被油漆或一些其他的適當涂料保護。當鋼被用于可能發生火災環境時, 鋼應該包圍在一些耐火的材料中, 例如石料或混凝土。通常,鋼的組合結構不易被壓碎除非是在冶金成分不好,低溫的不利組合, 或空間壓力存在的情況下。
建筑用鋁仍然不廣泛被在土木工程結構中用,雖然它的使用正在穩定地增加。藉著鋁合金作為一個適當的選擇和對其進行熱處理,可獲得各式各樣的強度特性。一些合金所展現的抗壓強度特性相似于鋼, 除線形彈性模量大約是7,000,000 牛/平方厘米,相當于剛的三分之一。質量輕和耐氧化是鋁的兩個主要優點。因為它的特性對熱處理是非常敏感的,當鉚接或焊接鋁的時候,一定要小心仔細。一些技術已為制造預制鋁組合配件及形成若干的美麗的設計良好的外型結構的鋁制結構而發展起來。組合房屋配件制造的一般程序藉由螺栓連接,這似乎是利用建筑用鋁的最有前途的方法。
加強和預應力混凝土是主要的建筑材料。天然的水泥混凝土已經被使用長達數世紀之久。現代的混凝土建筑興起于十九世紀中葉,盡管人造水泥被 Aspidin,一個英國人于1825年申請了專利.雖然一些建筑者和工程師在十九世紀后期用鋼筋混凝土作實驗, 但作為一種建筑材料它占統治地位是在二十世紀初期。后五十年鋼筋混凝土結構設計和建筑得到迅速發展, 早期在法國的 Freyssinet 和比利時的 Magnel被大量使用。
素混凝土作為建筑材料有一個非常嚴重的缺點:就是它的抗拉強度非常有限, 只是它的抗壓強度的十分之一。素混凝土不僅受拉破壞是脆性破壞,而且受壓破壞也是在沒有多大變形預兆的情況下發生的準脆性破壞。(當然,在鋼筋混凝土建筑中,可以得到適當的延性)。只有進行適當的養護和合理的選擇并且摻加適當的混合天加劑,否則 霜凍破壞能嚴重的損害混凝土。在長期荷載作用下混凝土在選擇設計受壓情況方面要仔細考慮。在硬化的時候和它的早期養護下,混凝土收縮占主要地位, 因此需要添加適當地比例的添加劑而且用適當的建筑技術來控制。
藉由所有的這些可能的嚴重缺點,工程師已經試著為各種實際結構設計建立美麗的,持久的,和經濟的鋼筋混凝土結構。這是藉著設計尺寸和鋼筋排列安排的謹慎選擇,和適當的水泥的發展已經趨于同步, 適當添加劑混合比例, 混合配置, 而且養護技術和建筑方法,儀器的快速發展。
混凝土具有多種用途,其組成材料廣泛可取,并且能非常方便地澆制成滿足強度及功能要求的形狀,同時,隨著新型預應力混凝土、預制混凝土以及普通混凝土施工方法令人興奮的進一步改善和發展的潛力,這些因素綜合起來使得混凝土在絕大多數結構中有著比其他材料更大的競爭力。
在現代,藉由鋼和加強鋼筋的使用量在建筑結構中的增加,木材在建筑期間主要地已經被撤離到附屬的、暫時的和次要的結構中使用,成為建筑材料的次要成員。然而, 現代的技術在最后六十年中已經有使木材作為建筑材料恢復生氣的跡象,藉由大量的改良了木材的加工方法,各種不同的處理方法增加了木材的耐久性, 而且疊片木材連同使用黏結技術的革命使得木材的性能有了更好的保證。各向同性的膠合板是最廣泛使用的壓層膠合板,隨著技術的發展,壓層膠合板已經發展成為特定的結構材料并對混凝土和鋼造成了強大的競爭力。
將來可能發展的材料是工程塑料和稀有金屬及他們的合金,如鈹,鎢,鉭,鈦,鉬,鉻,釩和鈮。有許多不同的塑料可以用,而且這些材料所展現的力學性能在很大的范圍內改變。在如此許多的特性中我比較設計方案選擇適當的可能的塑料材料是可能的。對塑料的使用受經驗的限制。一般而言,塑料一定要與空氣隔離。設計的這一個方面要求主要是對塑料結構元素在使用中的考慮。塑料被應用的最有希望的潛能之一是嵌板和貝殼型結構。疊片或夾心嵌板已經被用于此種結構以鼓勵未來建筑大量應用這一個類型材料。
另一種引起注意的材料由纖維或像粒子的膠結加筋的微粒組成的合成物材料正在開發。雖然一種由玻璃或塑料膠結材料組成的玻璃纖維加筋合成物已經被用長達數年之久, 但是他們很可能退落為次要的結構材料。加筋混凝土是另一個積極地被學習而且發展的混合料。一些實驗正在工作情況下進行。實驗主要內容為鋼和玻璃纖維,但是大部份的使用經驗在鋼纖維方面比較先進。
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Building materials The most serious disadvantage of steel is that it oxidizes easily and must be protected by paint or some other suitable coating.When steel is used in an enclosure where a fire could occur, the steel members must be encased in a suitable fire-resistant enclosure such as masonry, concrete.Normally, steel members will not fail in a brittle manner unless an unfortunate combination of metallurgical composition, low temperature, and bi-or triaxial stress exists.Structural aluminum is still not widely used in civil engineering structures, though its use is steadily increasing.By a proper selection of the aluminum alloy and its heat treatment, a wide variety of strength characteristics may be obtained.Some of the alloys exhibit stress-strain characteristics similar those of structural steel, except that the modulus of elasticity for the initial linearly elastic portion is about 10,000,000 psi(700,000 kgf/cm*cm)or about one-third that of steel.Lightness and resistance to oxidation are, of course, two of the major advantages of aluminum.Because its properties are very sensitive to its heat treatment, care must be used when riveting or welding aluminum.Several techniques have been developed for prefabricating aluminum subassemblies that can be readily erected and bolted together in the field to form a number of beautiful and well-designed shell structures.This general procedure of prefabrication and held assembly by bolting seems to be the most promising way of utilizing structural aluminum.Reinforced and prestesses concrete share with structural material.Natural cement concretes have been used for centuries.Modern concrete construction dates from the middle of the nineteenth century, though artificial Portland cement was patented by Aspidin, an Englishman, about 1825.Although several builders and engineers experimented with the use of steel-reinforced concrete in the last half of the nineteenth century, its dominant use as a building material dates from the early decades of the twentieth century.The last fifty years have seen the rapid and vigorous development of prestressed concrete design and construction, founded largely on early work by Freyssinet in France and Magnel in Belgium.Plain(unreinforced)concrete not only is a heterogeneous material but also has one very serious defect as a structural material, namely, its very limited tensile strength, which is only of the order of one-tenth its compressive strength.Not only is tensile failure in concrete of a brittle type, but likewise compression failure occurs in a relatively brittle fashion without being preceded by the forewarning of large deformations.(Of course, in reinforced-concrete construction, ductile behavior can be obtained by proper selection and arrangement of the reinforcement.)Unless proper care is used in the selection of aggregates and in the mixing and placing of concrete, frost action can cause serious damage to concrete masonry.Concrete creeps under long-term loading to a degree that must be considered carefully in selecting the design stress conditions.During the curing process and its early life, concrete shrinks a significant amount, which to a degree can be controlled by properly proportioning the mix and utilizing suitable construction techniques.With all these potentially serious disadvantages, engineers have learned to design and build beautiful, durable, and economical reinforced-concrete structures for practically all kinds of structural requirements.This has been accomplished by careful selection of the design dimensions and the arrangement of the steel reinforcement, development of proper cements, selection of proper aggregates and mix proportions, careful control of mixing, placing, and curing techniques and imaginative development of construction methods, equipment and procedures.The versatility of concrete, the wide availability of its component materials, the unique ease of shaping its form to meet strength and functional requirements, together with the exciting potential of further improvements and development of not only the newer prestressed and precast concrete
` construction but also the conventional reinforced concrete construction, combine to make concrete a strong competitor of other materials in a very large fraction of structures.In modern times, with the increased use of steel and reinforced-concrete construction, wood has been relegated largely to accessory use during construction, to use in temporary and secondary structures, and to use for secondary members of permanent construction.Modern technology in the last sixty years has revitalized wood as a structural material, however, by developing vastly improved timber connectors, various treatments to increase the durability of wood, and laminated wood made of thin layers bonded together with synthetic glues using revolutionary gluing techniques.Plywood with essentially nondirectional strength properties is
the most widely used laminated wood, but techniques have also been developed for building
large laminated wood members that for certain structures are competitive with concrete and steel.Materials with future possibilities are the engineering plastics and the exotic metals and their alloys, such as beryllium, tungsten, tantalum, titanium, molybdenum, chromium, vanadium, and niobium.There are many different plastics available, and the mechanical
properties exhibited by this group of materials vary over a wide range that encompasses the range of properties available among the more commonly used structural materials.Thus in many specific design applications it is possible to select a suitable plastic material for an alternative design.Experience with the use of plastics outdoors is limited.Generally speaking, however, plastics must be protected from the weather.This aspect of design is therefore a major consideration in the use of plastics for primary structural elements.One of the most promising potential used of plastics is for panel and shell-type structures.Laminated or sandwich panels have been used in such structures with encouraging results that indicate an increased use in this type of construction in the future.Another materials development with interesting possibilities is that of composites consisting of a matrix reinforced by fibers or fiber like particles.Although glass-fiber-reinforced composites with a glass or plastic matrix have been used for years, they appear to have much broader possibilities for a large variety of secondary structural components.Fiber-reinforced concrete is another composite being actively studied and developed.Several experimental applications are being observed under service conditions.Experiments have been conducted with both steel and glass fibers, but most of the service experience has been with steel fibers.`