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水利水电工程毕业设计英文翻译,混凝土重力坝

Concrete Gravity DamThe type of dam selected for a site depends principally on topographic, geologic,hydrologic, and climatic conditions. Where more than one type can be built, alternative economic estimates are prepared and selection is based on economica considerations.Safety and performance are primary requirements, but construction time and materials often affect economic comparisons.Dam ClassificationDams are classified according to construction materials such as concrete or earth. Concrete dams are further classified as gravity, arch, buttress, or a combination of these. Earthfill dams are gravity dams built of either earth or rock materials, with particular provisions for spillways and seepage control.A concrete gravity dam depends on its own weight for structural stability. The dam may be straight or slightly curved, with the water load transmitted through the dam to the foundation material. Ordinarily, gravity dams have a base width of 0.7 to 0.9 the height of the dam. Solid rock provides the best foundation condition. However, many small concrete dams are built on previous or soft foundations and perform satisfactorily. A concrete gravity dam is well suited for use with an overflow spillway crest. Because of this advantage, it is often combined with an earthfill dam in wide flood plain sites.Arch dams are well suited to narrow V- or U-shaped canyons. Canyon walls must be of rock suitable for carrying the transmitted water load to the sides of the canyon by arch action. Arch sections carry the greatest part of the load; vertical elements carry sufficient load through cantilever action to produce cantilever deflections equal to arch deflections. Ordinarily, the crest length-to-height ratio should be less than 5, although greater ratios have been used. Generally, the base width of modern arch dams is 0.1 to 0.3 the height of the impounded water. A spillway may be designed into the crest of an arch dam.Multiple arches similarly transmit loads to the abutment or ends of the arch. This type of dam is suited to wider valleys. The main thrust and radial shears are transmitted to massive buttresses and then into the foundation material.Buttress dams include flat-slab, multiple-arch, roundhead-buttress, and multiple-dome types. The buttress dam adapts to all site locations. Downstream face slabs and aprons are used for overflow spillways similar to gravity dam spillways. Inclined sliding gates or light-weight low-head gates control the flow.The water loads are transmitted to the foundation by two systems of load-carrying members. The flat slabs, arches, or domes support the direct water load. The face slabs are supported by vertical buttresses. In most flat-slab buttress dams, steel reinforcement is used to carry thetension forces developed in the face slabs and buttress supports. Massive-head buttresses eliminate most tension forces and steel is not necessary.Combiantion designs may utilize one or more of the previously mentioned types of dams. For example, studies may indicate that an earthfill dam with a center concrete gravity overflow spillway section is the most economial in a wide, flat valley. Other design conditions may dictate a multiple-arch and buttress dam section or a buttress and gravity dam combination.Site ExplorationThe dam location is determined by the project’s functions. The exact site within the general location must be determined by careful project consideration and systematic studies.In preliminary studies, two primary factors must be determined-the topography at the site and characteristics of the foundation materials. The first choice of the type of dam is based primarily on these two factors. However, the final choice will usually be controlled by construction cost if other site factors are also considered.Asite exploration requires the preparation of an accurate topographic map for each possible site in the general location. The scale of the maps should be large enough for layout. Exploration primarily determines the conditions that make sites usable or unusable.From the site explorations, tentative sketches can be made of the dam location and project features such as power plants. Physical features at the site must be ascertained in order to make a sketch of the dam and determine the position of materials and work plant during construction. Other factors that may affect dam selection are roadways,fishways, locks, and log passages.TopographyTopography often determines the type of dam. For example, a narrow V-shaped channel may dictate an arch dam. The topography indicates surface characteristics of the valley and the relation of the contours to the various requirements of the structure. Soundness of the rock surface must be included in the topographic study.In a location study, one should select the best position for the dam. An accurate sketch of the dam and how it fits into the topographic features of the valley are often sufficient to permit initial cost estimates. The tentative location of the other dam features should be included in this sketch since items such as spillways can influence the type and location of the dam.Topographic maps can be made from aerial surveys and subsequent contour plotting or they can be obtained from governmental agencies. The topographic survey should be correlated with the site exploration to ensure accuracy. Topographic maps give only the surface profile at thesite. Further geological and foundation analyses are necessary for a final determination of dam feasibility.Foundation and Geological InvestigationFoundation and geological conditions determine the factors that support the weight of the dam. The foundation materials limit the type of dam to a great extent, although such limitations can be compensated for in design.Initial exploration may consist of a few core holes drilled along the tentatively selected site location. Their analysis in relation to the general geology of the area often rules out certain sites as unfeasible, particularly as dam height increases. Once the number of possible site locations has been narrowed down, more detailed geological investiagtions should be considered.The location of all faults, contacts, zones of permeability, fissures, and other underground conditions must be accurately defined. The probable required excavation depth at all points should be derived from the core drill analysis. Extensive drilling into rock formations isn’t necessary for small dams. However, as dam height and safety requirements increase, investigations should be increased in depth and number. If foundation materials are soft, extensive investigations should determine their depth,permeability, and bearing capacity. It is not always necessary orpossible to put a concrete dam on solid rock.The different foundations commonly encountered for dam construction are: (1)solid rock foundations, (2) gravel foundations, (3) silt or fine sand foundations, (4) clay foundations, and (5) nonuniform foundation materials. Small dams on soft foundation ( item 2 through item 5 ) present some additonal design problems such as settlement, prevention of piping, excessive percolation, and protection of foundation from downstream toe erosion. These conditions are above the normal design forces of a concrete dam on a rock foundation. The same problems also exist for earth dams.Geological formations can often be pictured in cross-section by a qualified geologist if he has certain core drill holes upon which to base his overall concept of the geology. However, the plans and specifications should not contain this overall geological concept. Only the logs of the core drill holes should be included for the contractor’s estimates. However, the geological picture of the underlying formations is a great aid in evaluating the dam safety. The appendix consists of excerpts from a geologic report for the site used in the design examples.HydrologyHydrology studies are necessary to estimate diversion requirements during construction, to establish frequency of use of emergency spillways in conjunction with outlets or spillways, to determine peak dischargeestimates for diversion dams, and to provide the basis for power generation. Hydrologic studies are complex; however, simplified procedures may be used for small dams if certain conservative estimates are made to ensure structural safety.Formulas are only a guide to preliminary plans and design computations. The empirical equations provide only peak discharge estimates. However, the designer is more interested in the runoff volume associated with discharge and the time distribution of the flow. With these data, the designer knows both the peak discharge and the total inflow into the reservoir area. This provides a basis for making reliable diversion estimates for irrigation projects, water supply, or power generation.A reliable study of hydrology enables the designer to select the proper spillway capacity to ensure safety. The importance of a safe spillway cannot be overemphasized. Insufficient spillways have caused failures of dams. Adequate spillway capacity is of paramount importance for earthfill and rockfill dams. Concrete dams may be able to withstand moderate overtopping.Spillways release excess water that cannot be retained in the storage space of the reservoir. In the preliminary site exploration, the designer must consider spillway size and location. Site conditions greatly influence the selection of location, type, and components of a spillway. The design flows that the spillway must carry without endangering the dam areequally important. Therefore, study of streamflow is just as critical as the foundation and geological studies of the site.附录2外文翻译混凝土重力坝一个坝址的坝型选择，主要取决于地形、地质、水文和气候条件。

机械毕业设计英文外文翻译116电动平衡叉车

附录ATray selection and with the shelves, forklift matchFirst, the selected tray Size:When used plastic pallets, according to the requirements of the project, the selected size will be different.1. First, consider the specifications and packaging of goods placed in the plastic tray method. For example: the European standard turnover box size is 600 * 400mm, 1200 * 1000mm pallet in place a layer of 5 in 1200 * 800mm layer placed on the tray 4, the general stacking 5 layers.2. Consider the pallet loading tools (such as containers, trucks, etc.). For example: If you are working round-trip or one-time use, you need to give priority to the width of 2300mm of integrated container shipping, for 1200 * 1000mm pallet, length 1200mm and width 1000mm to use a combination of place, must be selected to enter the fork 4. The tray on the 1200 * 800mm, 800mm width direction with two side by side. The pallet of 1100 * 1100mm width by 1100mm, placed 2, 2, or 4 to enter the fork into the fork can be.3. If used in the warehouse shelves, shelves to consider the size of width and depth, usually select the shelves each placed two trays of each cargo space, and allow access to the space of about 200mm. In depth directionas far as possible to give large size, this does not produce plastic pallets carrying capacity of the stringent requirements in order to save procurement costs.4. If the use of automated warehouse shelves, in addition to meet the above requirements, but also take into account the slip coefficient of the tray, the tray bottom with transmission equipment and chain, into the fork height, carrying capacity on the shelves, permanent deformation, length of surface deflection, the position of bar coding and RFID chips placed on other factors.5. Use plastic trays should also consider the size of generality, the size of the domestic common international standard for the 1210, 1208 European standard and T11 Japanese standard tray.Second, the choice of single and double-sided:1. Single use plastic pallets only one side, the surface grid of two peace-plate, the bottom of Sichuan fonts, font, or nine square field pad feet, according to carrying capacity and the use of different occasions into shelf series, standard series and ultra-light series of three standards.2. Sided plastic tray that the same structure on both sides of the tray, the surface grid plate of peace are two sides to exchange used, based on carrying capacity and the use of different occasions, the shelves are divided into two series and standard series standards.3. Use double-sided tray or trays should be based on the appropriatestorage, loading and unloading equipment and state (such as the library type, rack type, stacking or placing the state, etc.) to determine.4. For the small footprint of the ASRS or high shelves, or electric stacker forklift to move vertically oriented occasion, single-sided double-sided shelf series shelf series of trays and trays can be chosen.5. If the three-dimensional library or load up on the shelves of 1T, but there is no ceiling shelves, the proposed shelf tray with built-in pipe. Steel structure steel tray built an effective solution to the product on the shelf load the greater the greater the weight, the old problem of high cost, more importantly, about the use of square steel tube wall thickness of 2mm rigid, reaching the shelves (ASRS) are horizontal and vertical deflection ≤ 10mm stringent requirements, while reducing the permanent deformation and reduce costs.6. For the area, mainly the large and the level of the occasion, if the manual handling hydraulic pallet truck is suitable for use single-sided tray. For stacking of goods to the bottom of the tray above and below the cargo coincide, the swastika with the end of double-sided tray or tray-type side is better. If using self-moving motorized pallet trucks are suitable for articles not connected with the bottom of the nine feet single tray.Third, the load requirements1. Dynamic load refers to the use of electric forklift or a manual hydraulicpallet truck can lift the maximum weight allowed. General shelf tray to load-bearing 1.5T-2T, the standard load-bearing pallet can 1T, lightweight tray dynamic load 0.5T.2. Static load refers to the stacking, the bottom of the plastic tray can bear maximum weight. General shelf tray to load-bearing 6T-8T, the standard load-bearing pallet can 4T, lightweight tray static 1T.3. Shelf load refers to the plastic tray packaging on the shelves when the maximum allowable weight. Must pay attention to dynamic load, static load, load library shelf load and establish the difference between carrying capacity and shelves of different structures, closely related to ambient temperature and storage period. General heavy trays on a shelf in load-bearing beams 0.7T-1T, standard tray loading 0.4T-0.6T.4. Shelf load permanent deformation of the plastic tray and deflection have certain requirements, national standards for the maximum deflection 30mm, but this was partial width. We recommend using the deflection on the shelf no more than 20mm of plastic pallets. If the automatic warehouse, the requirements of the degree of deflection even more stringent, generally require less than 10mm. Cheng Machinery silver mesh)附录B电动平衡叉车是以直流电源（电瓶）为动力的装卸及搬运车辆。

采矿工程毕业设计_外文翻译英译汉中英文

ROOM-AND-PILLAR METHOD OF OPEN-STOPE MINING空场采矿法中的房柱采矿法Chapter 1.A Classification of the Room-and-Pillar Method of Open-Stope Mining第一部分，空场采矿的房柱法的分类OPEN STOPING空场采矿法An open stope is an underground cavity from which the initial ore has been mined. Caving of the opening is prevented (at least temporarily) by support from the unmined ore or waste left in the stope,in the form of pillars,and the stope walls (also called ribs or abutments). In addition to this primary may also be required using rockbolts , reinforcing rods, split pipes ,or shotcrete to stabilize the rock surface immediately adjacent to the opening. The secondary reinforcement procedure does not preclude the method classified as open stoping.露天采场台阶是开采了地下矿石后形成的地下洞室。

通过块矿或采场的支柱和（也称为肋或肩）采场墙形式的废料的支持来（至少是暂时的）预防放顶煤的开幕。

除了这个，可能还需要使用锚杆，钢筋棒，分流管，或喷浆，以稳定紧邻开幕的岩石表面。

办公楼毕业设计英文翻译(外文翻译)

办公楼毕业设计英文翻译（外文翻译）原文：The future of the tall buildingAnd structure of buildingsZoning effects on the density of tall buildings and solar design may raise ethical challenge.A combined project of old and new buildings may bring back human scale to our cities. Owners and conceptual designers will be challenged in the 1980s to produce economically sound, people-oriented buildings.In 1980 the Level House, designed by Skidmore, Owings and Merril1 (SOM) received the 25-year award from the American Institut e of Architects “in recognition of architectural design of enduring significance”. This award is given once a year for a building between 25and 35 years old .Lewis Mumford described the Lever House as “the first office building in which modern materials, m odern construction, modern functions have been combined with a modern plan”. At the time, this daring concept could only be achieved by visionary men like Gordon Bunshaft , the designer , and Charles Luckman , the owner and then-president of Lever Brothers . The project also included a few “first” : (1) it was the first sealed glass tower ever built ; (2) it was the first office building designed by SOM ;and (3) it was the first office building on Park Avenue to omit retail space on the first floor. Today, after hundreds of look-alike and variations on the grid design, we have reached what may be the epitome of tall building design: the nondescript building. Except for a few recently completed buildings that seem to be people-oriented in their lower floors, most tall buildings seem to be a repletion of the dull, graph-paper-like monoliths in many of our cities. Can this be the end of the design-line for tall buildings? Probably not. There are definite signs that are most encouraging. Architects and owners have recently begun to discuss the design problem publicly. Perhaps we are at the threshold of a new era. The 1980s may bring forth some new visionaries like Bunshaft and Luckman. If so, what kinds of restrictions or challenges do they face?译文：高层建筑展望及建筑结构区域规划对高层建筑物的密度和对自然采光设计可能引起道德问题将产生影响。

java毕业设计中英文翻译

java毕业设计中英文翻译篇一：JAVA外文文献+翻译Java and the InternetIf Java is, in fact, yet another computer programming language, you may question why it is so important and why it is being promoted as a revolutionary step in computer programming. The answer isn’t immediately obvious if you’re coming from a traditional programming perspective. Although Java is very useful for solving traditional stand-alone programming problems, it is also important because it will solve programming problems on the World Wide Web.1. Client-side programmingThe Web’s initial server-browser design provided for interactive content, but the interactivity was completely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them. Basic HTML contains simple mechanisms for data gathering: text-entry boxes, check boxes, radio boxes, lists and drop-down lists, as well as a button that can only be programmed to reset the data on the form or “submit” the data on the form backto the server. This submission passes through the Common Gateway Interface (CGI) provided on all Web servers. The text within the submission tells CGI what to do with it. The most common action is to run a program located on the server in a directory that’s typically called “cgi-bin.” (If you watch the address window at the top of your browser when you push a button on a Web page, you can sometimes see “cgi-bin” within all the gobbledygook there.) These programs can be written in most languages. Perl is a common choice because it is designed for text manipulation and is interpreted, so it can be installed on any server regardless of processor or operating system. Many powerful Web sites today are built strictly on CGI, and you can in fact do nearly anything with it. However, Web sites built on CGI programs can rapidly become overly complicated to maintain, and there is also the problem of response time. The response of a CGI program depends on how much data mustbe sent, as well as the load on both the server and the Internet. (On top of this, starting a CGI program tends to be slow.) The initial designers of the Web didnot foresee how rapidly this bandwidth would be exhausted for the kinds of applications people developed. For example, any sort of dynamic graphing is nearly impossible to perform with consistency because a GIF file must be created and moved from the server to the client for each version of the graph. And you’ve no doubt had direct experience with something as simple as validating the data on an input form. You press the submit button on a page; the data is shipped back to the server; the server starts a CGI program that discovers an error, formats an HTML page informing you of the error, and then sends the page back to you; you must then back up a page and try again. Not only is this slow, it’s inelegant.The solution is client-side programming. Most machines that run Web browsers are powerful engines capable of doing vast work, and with the original static HTML approach they are sitting there, just idly waiting for the server to dish up the next page. Client-side programming means that the Web browser is harnessed to do whatever work it can, and the result for the user is a much speedier and more interactive experience atyour Web site.The problem with discussions of client-side programming is that they aren’t very different from discussions of programming in general. The parameters are almost the same, but the platform is different: a Web browser is like a limited operating system. In the end, you must still program, and this accounts for the dizzying array of problems and solutions produced by client-side programming. The rest of this section provides an overview of the issues and approaches in client-side programming.2.Plug-insOne of the most significant steps forward in client-side programming is the development of the plug-in. This is a way for a programmer to add new functionality to the browser by downloading a piece of code that plugs itself into the appropriate spot in the browser. It tells the browser “from now on you can perform this new activity.” (You need to download the plug-in only once.) Some fast and powerful behavior is added to browsers via plug-ins, but writing a plug-in is not a trivial task, and isn’t something you’d wantto do as part of the process of building a particular site. The value of the plug-in for client-side programming is that it allows an expert programmer to develop a new language and add that language to a browser without the permission of the browser manufacturer. Thus, plug-ins provide a “back door”that allows the creation of new client-side programming languages (although not all languages are implemented as plug-ins).3.Scripting languagesPlug-ins resulted in an explosion of scripting languages. With a scripting language you embed the source code for your client-side program directly into the HTML page, and the plug-in that interprets that language is automatically activated while the HTML page is being displayed. Scripting languages tend to be reasonably easy to understand and, because they are simply text that is part of an HTML page, they load very quickly as part of the single server hit required to procure that page. The trade-off is that your code is exposed for everyone to see (and steal). Generally, however, you aren’t doing amazingly sophisticatedthings with scripting languages so this is not too much of a hardship.This points out that the scripting languages used inside Web browsers are really intended to solve specific types of problems, primarily the creation of richer and more interactive graphical user interfaces (GUIs). However, a scripting language might solve 80 percent of the problems encountered in client-side programming. Your problems might very well fit completely within that 80 percent, and since scripting languages can allow easier and faster development, you should probably consider a scripting language before looking at a more involved solution such as Java or ActiveX programming.The most commonly discussed browser scripting languages are JavaScript (which has nothing to do with Java; it’s named that way just to grab some of Java’s marketing momentum), VBScript (which looks like Visual Basic), andTcl/Tk, which comes from the popular cross-platform GUI-building language. There are others out there, and no doubt more in development.JavaScript is probably the most commonly supported. It comes built into both Netscape Navigator and the Microsoft Internet Explorer (IE). In addition, there are probably more JavaScript books available than there are for the other browser languages, and some tools automatically create pages using JavaScript. However, if you’re already fluent in Visual Basic or Tcl/Tk, you’ll be more productive using those scripting languages rather than learning a new one. (You’ll have your hands full dealing with the Web issues already.)4.JavaIf a scripting language can solve 80 percent of the client-side programming problems, what about the other 20 percent—the “really hard stuff?” The most popular solution today is Java. Not only is it a powerful programming language built to be secure, cross-platform, and international, but Java is being continually extended to provide language features and libraries that elegantly handle problems that are difficult in traditional programming languages, such as multithreading, database access, network programming, and distributed computing. Java allowsclient-side programming via the applet.An applet is a mini-program that will run only under a Web browser. The applet is downloaded automatically as part of a Web page (just as, for example, a graphic is automatically downloaded). When the applet is activated it executes a program. This is part of its beauty—it provides you with a way to automatically distribute the client software from the server at the time the user needs the client software, and no sooner. The user gets the latest version of the client software without fail and without difficult reinstallation. Because of the way Java is designed, the programmer needs to create only a single program, and that program automatically works with all computers that have browsers with built-in Java interpreters. (This safely includes the vast majority of machines.) Since Java is a full-fledged programming language, you can do as much work as possible on the client before and after making requests of theserver. For example, you won’t need to send a request form across the Internet to discover that you’ve gotten a date or some other parameter wrong, and yourclient computer can quickly do the work of plotting data instead of waiting for the server to make a plot and ship a graphic image back to you. Not only do you get the immediate win of speed and responsiveness, but the general network traffic and load on servers can be reduced, preventing the entire Internet from slowing down.One advantage a Java applet has over a scripted program is that it’s in compiled form, so the source code isn’t available to the client. On the other hand, a Java applet can be decompiled without too much trouble, but hiding your code is often not an important issue. Two other factors can be important. As you will see later in this book, a compiled Java applet can comprise many modules and take multiple server “hits” (accesses) to download. (In Java 1.1 and higher this is minimized by Java archives, called JAR files, that allow all the required modules to be packaged together and compressed for a single download.) A scripted program will just be integrated into the Web page as part of its text (and will generally be smaller and reduce server hits). This could be important to the responsiveness of your Website. Another factor is the all-important learning curve. Regardless of what you’ve heard, Java is not a trivial language to learn. If you’re a Visual Basic programmer, moving to VBScript will be your fastest solution, and since it will probably solve most typical client/server problems you might be hard pressed to justify learning Java. If you’re experienced with a scripting language you will certainly benefit from looking at JavaScript or VBScript before committing to Java, since they might fit your needs handily and you’ll be more productive sooner.to run its applets withi5.ActiveXTo some degree, the competitor to Java is Microsoft’s ActiveX, although it takes a completely different approach. ActiveX was originally a Windows-only solution, although it is now being developed via an independent consortium to become cross-platform. Effectively, ActiveX says “if your program connects to篇二：JAVA思想外文翻译毕业设计文献来源：Bruce Eckel. Thinking in Java [J]. Pearson Higher Isia Education,XX-2-20.Java编程思想 (Java和因特网)既然Java不过另一种类型的程序设计语言，大家可能会奇怪它为什么值得如此重视，为什么还有这么多的人认为它是计算机程序设计的一个里程碑呢？如果您来自一个传统的程序设计背景，那么答案在刚开始的时候并不是很明显。

毕业设计中英文翻译

Bridge Waterway OpeningsIn a majority of cases the height and length of a bridge depend solely upon the amount of clear waterway opening that must be provided to accommodate the floodwaters of the stream. Actually, the problem goes beyond that of merely accommodating the floodwaters and requires prediction of the various magnitudes of floods for given time intervals. It would be impossible to state that some given magnitude is the maximum that will ever occur, and it is therefore impossible to design for the maximum, since it cannot be ascertained. It seems more logical to design for a predicted flood of some selected interval ---a flood magnitude that could reasonably be expected to occur once within a given number of years. For example, a bridge may be designed for a 50-year flood interval; that is, for a flood which is expected (according to the laws of probability) to occur on the average of one time in 50 years. Once this design flood frequency, or interval of expected occurrence, has been decided, the analysis to determine a magnitude is made. Whenever possible, this analysis is based upon gauged stream records. In areas and for streams where flood frequency and magnitude records are not available, an analysis can still be made. With data from gauged streams in the vicinity, regional flood frequencies can be worked out; with a correlation between the computed discharge for the ungauged stream and the regional flood frequency, a flood frequency curve can be computed for the stream in question. Highway CulvertsAny closed conduit used to conduct surface runoff from one side of a roadway to the other is referred to as a culvert. Culverts vary in size from large multiple installations used in lieu of a bridge to small circular or elliptical pipe, and their design varies in significance. Accepted practice treats conduits under the roadway as culverts. Although the unit cost of culverts is much less than that of bridges, they are far more numerous, normally averaging about eight to the mile, and represent a greater cost in highway. Statistics show that about 15 cents of the highway construction dollar goes to culverts, as compared with 10 cents for bridge. Culvert design then is equally as important as that of bridges or other phases of highway and should be treated accordingly.Municipal Storm DrainageIn urban and suburban areas, runoff waters are handled through a system of drainage structures referred to as storm sewers and their appurtenances. The drainage problem is increased in these areas primarily for two reasons: the impervious nature of the area creates a very high runoff; and there is little room for natural water courses. It is often necessary to collect the entire storm water into a system of pipes and transmit it over considerable distances before it can be loosed again as surface runoff. This collection and transmission further increase the problem, since all of the water must be collected with virtually no ponding, thus eliminating any natural storage; and though increased velocity the peak runoffs are reached more quickly. Also, the shorter times of peaks cause the system to be more sensitive to short-duration, high-intensity rainfall. Storm sewers, like culverts and bridges, are designed for storms of various intensity –return-period relationship, depending upon the economy and amount of ponding that can be tolerated.Airport DrainageThe problem of providing proper drainage facilities for airports is similar in many ways to that of highways and streets. However, because of the large and relatively flat surface involved the varying soil conditions, the absence of natural water courses and possible side ditches, and the greater concentration of discharge at the terminus of the construction area, some phases of the problem are more complex. For the average airport the overall area to be drained is relatively large and an extensive drainage system is required. The magnitude of such a system makes it even more imperative that sound engineeringprinciples based on all of the best available data be used to ensure the most economical design. Overdesign of facilities results in excessive money investment with no return, and underdesign can result in conditions hazardous to the air traffic using the airport.In other to ensure surfaces that are smooth, firm, stable, and reasonably free from flooding, it is necessary to provide a system which will do several things. It must collect and remove the surface water from the airport surface; intercept and remove surface water flowing toward the airport from adjacent areas; collect and remove any excessive subsurface water beneath the surface of the airport facilities and in many cases lower the ground-water table; and provide protection against erosion of the sloping areas. Ditches and Cut-slope DrainageA highway cross section normally includes one and often two ditches paralleling the roadway. Generally referred to as side ditches these serve to intercept the drainage from slopes and to conduct it to where it can be carried under the roadway or away from the highway section, depending upon the natural drainage. To a limited extent they also serve to conduct subsurface drainage from beneath the roadway to points where it can be carried away from the highway section.A second type of ditch, generally referred to as a crown ditch, is often used for the erosion protection of cut slopes. This ditch along the top of the cut slope serves to intercept surface runoff from the slopes above and conduct it to natural water courses on milder slopes, thus preventing the erosion that would be caused by permitting the runoff to spill down the cut faces.12 Construction techniquesThe decision of how a bridge should be built depends mainly on local conditions. These include cost of materials, available equipment, allowable construction time and environmental restriction. Since all these vary with location and time, the best construction technique for a given structure may also vary. Incremental launching or Push-out MethodIn this form of construction the deck is pushed across the span with hydraulic rams or winches. Decks of prestressed post-tensioned precast segments, steel or girders have been erected. Usually spans are limited to 50～60 m to avoid excessive deflection and cantilever stresses , although greater distances have been bridged by installing temporary support towers . Typically the method is most appropriate for long, multi-span bridges in the range 300 ~ 600 m ,but ,much shorter and longer bridges have been constructed . Unfortunately, this very economical mode of construction can only be applied when both the horizontal and vertical alignments of the deck are perfectly straight, or alternatively of constant radius. Where pushing involves a small downward grade (4% ~ 5%) then a braking system should be installed to prevent the deck slipping away uncontrolled and heavy bracing is then needed at the restraining piers.Bridge launching demands very careful surveying and setting out with continuous and precise checks made of deck deflections. A light aluminum or steel-launching nose forms the head of the deck to provide guidance over the pier. Special teflon or chrome-nickel steel plate bearings are used to reduce sliding friction to about 5% of the weight, thus slender piers would normally be supplemented with braced columns to avoid cracking and other damage. These columns would generally also support the temporary friction bearings and help steer the nose.In the case of precast construction, ideally segments should be cast on beds near the abutments and transferred by rail to the post-tensioning bed, the actual transport distance obviously being kept to the minimum. Usually a segment is cast against the face of the previously concerted unit to ensure a good fit when finally glued in place with an epoxy resin. If this procedure is not adopted , gaps of approximately 500mm shold be left between segments with the reinforcements running through andstressed together to form a complete unit , but when access or space on the embankment is at a premium it may be necessary to launch the deck intermittently to allow sections to be added progressively .The correponding prestressing arrangements , both for the temporary and permanent conditions would be more complicated and careful calculations needed at all positions .The pricipal advantage of the bridge-launching technique is the saving in falsework, especially for high decks. Segments can also be fabricated or precast in a protected environment using highly productive equipment. For concrete segment, typically two segment are laid each week (usually 10 ~ 30 m in length and perhaps 300 to 400 tonnes in weight) and after posttensioning incrementally launched at about 20 m per day depending upon the winching/jacking equipment.Balanced Cantiulever ConstructionDevelopment in box section and prestressed concrete led to short segment being assembled or cast in place on falsework to form a beam of full roadway width. Subsequently the method was refined virtually to eliminate the falsework by using a previously constructed section of the beam to provide the fixing for a subsequently cantilevered section. The principle is demonsrated step-by-step in the example shown in Fig.1.In the simple case illustrated, the bridge consists of three spans in the ratio 1:1:2. First the abutments and piers are constructed independently from the bridge superstructure. The segment immediately above each pier is then either cast in situ or placed as a precast unit .The deck is subsequently formed by adding sections symmetrically either side.Ideally sections either side should be placed simultaneously but this is usually impracticable and some inbalance will result from the extra segment weight, wind forces, construction plant and material. When the cantilever has reached both the abutment and centre span,work can begin from the other pier , and the remainder of the deck completed in a similar manner . Finally the two individual cantilevers are linked at the centre by a key segment to form a single span. The key is normally cast in situ.The procedure initially requires the first sections above the column and perhaps one or two each side to be erected conventionally either in situ concrete or precast and temporarily supported while steel tendons are threaded and post-tensioned . Subsequent pairs of section are added and held in place by post-tensioning followed by grouting of the ducts. During this phase only the cantilever tendons in the upper flange and webs are tensioned. Continuity tendons are stressed after the key section has been cast in place. The final gap left between the two half spans should be wide enough to enable the jacking equipment to be inserted. When the individual cantilevers are completed and the key section inserted the continuity tendons are anchored symmetrically about the centre of the span and serve to resist superimposed loads, live loads, redistribution of dead loads and cantilever prestressing forces.The earlier bridges were designed on the free cantilever principle with an expansion joint incorporated at the center .Unfortunately，settlements , deformations , concrete creep and prestress relaxation tended to produce deflection in each half span , disfiguring the general appearance of the bridge and causing discomfort to drivers .These effects coupled with the difficulties in designing a suitable joint led designers to choose a continuous connection, resulting in a more uniform distribution of the loads and reduced deflection. The natural movements were provided for at the bridge abutments using sliding bearings or in the case of long multi-span bridges, joints at about 500 m centres.Special Requirements in Advanced Construction TechniquesThere are three important areas that the engineering and construction team has to consider:(1) Stress analysis during construction: Because the loadings and support conditions of the bridge are different from the finished bridge, stresses in each construction stage must be calculated to ensurethe safety of the structure .For this purpose, realistic construction loads must be used and site personnel must be informed on all the loading limitations. Wind and temperature are usually significant for construction stage.(2) Camber: In order to obtain a bridge with the right elevation, the required camber of the bridge at each construction stage must be calculated. It is required that due consideration be given to creep and shrinkage of the concrete. This kind of the concrete. This kind of calculation, although cumbersome, has been simplified by the use of the compiters.(3) Quality control: This is important for any method construction, but it is more so for the complicated construction techniques. Curing of concrete, post-tensioning, joint preparation, etc. are detrimental to a successful structure. The site personnel must be made aware of the minimum concrete strengths required for post-tensioning, form removal, falsework removal, launching and other steps of operations.Generally speaking, these advanced construction techniques require more engineering work than the conventional falsework type construction, but the saving could be significant.大桥涵洞在大多数情况中桥梁的高度和跨度完全取决于河流的流量，桥梁的高度和跨度必须能够容纳最大洪水量.事实上，这不仅仅是洪水最大流量的问题,还需要在不同时间间隔预测不同程度的水灾。

毕业设计(英文翻译)

附录G：英文翻译参考（要求学生完成与论文有关的外文资料中文字数5000字左右的英译汉，旨在培养学生利用外文资料开展研究工作的能力，为所选课题提供前沿参考资料。

）毕业设计（英文翻译）题目系别：专业：班级：学生姓名：学号：指导教师：一位从事质量管理的人约瑟夫·朱兰出生于圣诞夜,1904 在罗马尼亚的喀尔巴阡山脉山中。

他青年时期的村庄中贫穷、迷信和反犹太主义甚是猖獗。

1912年朱兰家搬到了明尼阿波尼斯州，虽然充满了危险，但是它却让一个男孩充满信心和希望。

从如此多了一个在质量观念的世界最好改革者之一。

在他90年的生活中，朱兰一直是一个精力充沛的思想者倡导者，推动着传统的质量思想向前走。

因为九岁就被雇用,朱兰表示在他的生活工作上永不停止。

记者:技术方面如何讲质量?朱兰:技术有不同方面:一、当然是精密。

物的对精密的需求像电子学、化学…我们看来它们似乎需要放大来说,和重要的原子尘的有关于质量。

要做到高精密具有相当大的挑战，而且我们已经遇见非常大的挑战。

另外的一个方面是可信度－没有失败。

当我们举例来说建立一个系统，同类空中交通管制的时候,我们不想要它失败。

我们必须把可信度建入系统。

因为我们投入很大的资金并依赖这些系统，系统非常复杂，这是逐渐增加的。

除此之外,有对公司的失败费用。

如果事物在领域中意外失败,可以说，它影响民众。

但是如果他们失败在内部,然后它影响公司的费用,而且已经试着发现这些费用在哪里和该如何免除他们。

因此那些是相当大的因素:精密、可信度和费用。

还有其它的,当然，但是我认为这些是主要的一些。

记者:据说是质量有在美国变成一种产业的可能?朱兰:资讯科技当然有。

已经有大的变化。

在世纪中初期当质量的一个想法到一个检验部门的时候，这有了分开的工作，东西被做坏之后。

检验是相当易错的程序,实际上。

而且无论如何，资讯科技在那天中相当花时间，直到某事已经被认为是否资讯科技是正确的。

应该强调计划，如此它不被错误首先订定。

华南理工大学毕业设计外文翻译

华南理工大学本科毕业设计（论文）翻译班级土木工程三班姓名王剑锋学号 200930132042指导教师骆冠勇填表日期 2013年4月21日中文译名一种用于预测拉森钢板桩弯曲强度的数值模型外文原文名 A numerical model for predicting the bending strength of Larssen steel sheetpiles外文原文版出处Journal of Constructional Steel Research 58 (2002) 1361–1374译文：一种用于预测拉森钢板桩弯曲强度的数值模型R.J. Crawford, M.P. Byfield摘要拉森桩为U形横截面并通过可滑动的接头连接在一起组成码头岸壁，围堰，和其他类型的挡土墙。

由于滑动接头位于桩墙的中心线上，相互连接桩的桩间滑移可能导致桩墙70%的弯曲强度折减。

这种桩间滑移可以通过安装成对的带有卷曲的锁头的桩来部分阻止。

然而，像非卷曲桩一样弯曲强度很难被预测，因为这种联锁桩依然存在桩间滑移。

本文提出了一种用于预测联锁拉森桩弯曲应力以及压应力的数值方法。

通过测试1：6比例大小的铝制拉森桩微缩模型的数据与数值模型计算结果进行比较，结果表明数值模型所预测的应力与实际实验结果接近一致。

同时本数值模型也可用于钢板桩的设计生产，以达到使用最少的材料来达到最大的弯曲强度的目的。

C 2002爱思唯尔股份有限公司保留解释权利关键词：行业规范；组合结构；拉森桩；桩结构；挡土墙；钢结构1.介绍钢板桩被广泛运用于全世界。

工程上经常使用的两种钢板桩是U型拉森钢板桩和Z型钢板桩。

两种类型的钢板桩桩都是利用沿着构件长度方向的锁头连接成有缝的连续墙结构。

根据欧洲标准化委员会引入的欧3标准第五部分，U型钢板桩锁头连接部分的下滑位移的影响不能忽视（见图1 步骤1）。

如果钢板桩单肢的相对滑移严重，则钢板桩的弯曲强度会下降到整体强度的70%，我们将其称为钢板桩模量下降。

毕业设计豆浆机外文翻译

Soy milk maker‎From Wikip‎e dia, the free encyc‎l oped‎i aExamp‎l e of one of the many diffe‎r ent kinds‎of soy milk maker‎sA soy milk maker‎is a small‎kitch‎e n appli‎a nce which‎autom‎a tica‎l ly cooks‎soy milk, a non-dairy‎bever‎a gemade from soy beans‎. Soy milk maker‎s work simil‎a rly to a combi‎n atio‎n betwe‎e n a home blend‎e r and an autom‎a tic coffe‎e maker‎. Some soy milk maker‎s can also be progr‎a mmed‎to make almon‎d milk, rice milk andother‎veget‎a ble-based‎steep‎e d bever‎a ges.Home-made soy milk can be made to the drink‎e rs' taste‎s and nutri‎t iona‎l requi‎r emen‎t s, provi‎d ing added‎value‎.Soy pulp or okara‎, a healt‎h y by-produ‎c t of soy milkprepa‎r atio‎n, can be used as an ingre‎d ient‎in manyrecip‎e s and food produ‎c ts.Ordin‎a ry metho‎d s for makin‎g soy milk at home are often‎very labor‎-inten‎s ive (requi‎r ing beans‎to be soake‎d, groun‎d in a blend‎e r, strai‎n ed, and then cooke‎d). Soy milk machi‎n es perfo‎r m many of these‎steps‎autom‎a tica‎l ly, great‎l y simpl‎i fyin‎ghome-based‎soy milk produ‎c tion‎.Stand‎a rd opera‎t ionBefor‎e use, dried‎beans‎are rinse‎d with water‎to remov‎e parti‎c ulat‎e debri‎s, soake‎d for 6–10 hours‎to moist‎e n and softe‎n the dried‎beans‎, and then rinse‎d again‎befor‎e use. The moist‎e ned soy beans‎are place‎d into the grind‎i ng chamb‎e r, where‎they are groun‎d into a fine paste‎, and fall into a finel‎y scree‎n ed strai‎n er chamb‎e r immer‎s ed in a pot of water‎.The paste‎is steep‎e d in the water‎in a proce‎s s simil‎a r to that of tea makin‎g; the pot of water‎is heate‎d, fully‎cooki‎n g both the disso‎l ved soy milk and the strai‎n ed soy solid‎s, which‎becom‎e okara‎. The new model‎s on the marke‎t now have no filte‎r cup—soy beans‎are place‎d direc‎t ly insid‎e the machi‎n e jug.Most soy milk maker‎s inclu‎d e a mecha‎n ism to stop the boili‎n g soy milk fromoverf‎l owin‎g. The heate‎r is turne‎d off as the water‎level‎appro‎a ches‎the top of the chamb‎e r, and then turne‎d back on as the soy milk retur‎n s to an accep‎t able‎level‎. This proce‎s s is repea‎t ed for the lengt‎h of the cooki‎n g perio‎d, which‎lasts‎for appro‎x imat‎e ly fifte‎e n minut‎e s.When the soy milk has fully‎cooke‎d, the machi‎n e will autom‎a tica‎l ly turn off, leavi‎n g the okara‎in the filte‎r cup and the soy milk in the water‎chamb‎e r. Many machi‎n es will beep to infor‎m the user of the soy milk's compl‎e tion‎.Revie‎w of popul‎a r soy milk maker‎somMak‎i ng your own soy milk with a soymi‎l k maker‎is very easy, allow‎s you to save a lot of money‎and you know exact‎l y what the ingre‎d ient‎s are. If neede‎d, you can add extra‎ingre‎d ient‎s such as sugar‎, sweet‎e ners‎, flavo‎u rs, thick‎e ners‎and salt to make it taste‎more like indus‎t rial‎soy milk. Makin‎g soy milk with norma‎l kitch‎e n tools‎is also possi‎b le, but requi‎r es more time and resul‎t s in a lower‎yield‎. Basic‎a lly you have to add the soake‎d soybe‎a ns and water‎to the soy milk maker‎and press‎the start‎butto‎n. We have teste‎d the follo‎w ing soy milk maker‎s with filte‎r cup: SoyQu‎i ck, Vegan‎Star, SoyaJ‎o y,SoyaP‎o wer, SoyWo‎n der and QT400‎, and two filte‎r less‎soy milk maker‎s: Premi‎u m SoyQu‎i ck and SoyaD‎i rect‎. The SoyaD‎i rect‎belon‎g s to the newes‎t gener‎a tion‎of soy milk maker‎s that use no filte‎r cups or grind‎i ng cover‎, makin‎g clean‎i ng and handl‎i ng easie‎r. You can order‎this machi‎n e from the UK based‎compa‎n y Soyad‎i rect‎. When order‎i ng, pleas‎e do not forge‎t to menti‎o n our speci‎a l promo‎t ion code SYBE0‎9, which‎gives‎you an extra‎disco‎u nt of 10% off produ‎c t sale price‎.Compo‎n ents‎of a soymi‎l k maker‎Most model‎s are compo‎s ed of the follo‎w ing parts‎:∙Heati‎n g eleme‎n t: this can be a heati‎n g eleme‎n t which‎is subme‎r ged in the liqui‎d or a heati‎n g botto‎m plate‎. Both syste‎m s also exist‎with norma‎l water‎boile‎r.∙ A conta‎i ner which‎will hold the soy milk plus some extra‎air space‎to preve‎n t overc‎o okin‎g. This conta‎i ner can be plast‎i c or stain‎l ess steel‎.∙ A filte‎r cup which‎holds‎the soy beans‎. The surfa‎c e consi‎s ts of a scree‎n which‎allow‎s water‎or soy milk to pass throu‎g h. There‎are two types‎of scree‎n s: a thin plate‎with very small‎round‎holes‎(Soyaj‎o y, SoyaP‎o wer and Vegan‎Star) and a fine mesh scree‎n (SoyWo‎n der).∙Senso‎r s to preve‎n t the overc‎o okin‎g of the soymi‎l k.∙Motor‎with stain‎l ess steel‎stirr‎i ng blade‎to mix the soybe‎a ns.∙ A micro‎p roce‎s sors‎to contr‎o l the proce‎s s of heati‎n g and mixin‎g.∙Some autom‎a tic soy milk maker‎s have addit‎i onal‎parts‎or optio‎n s: a feedi‎n g windo‎w or openi‎n g which‎allow‎s you to add the beans‎to the fully‎assem‎b led soy milk maker‎(Soyaj‎o ys and SoyaP‎o wer) or a kit to make tofu.Opera‎t ion of an autho‎m atic‎soy milk maker‎The opera‎t ion instr‎u ctio‎n s diffe‎r sligh‎t ly betwe‎e n the diffe‎r ent brand‎s but basic‎a lly they work like this:∙Weigh‎or measu‎r e 80 to 100 grams‎of dry soybe‎a ns for each liter‎of soy milk.Norma‎l ly a measu‎r ing cup is provi‎d ed.∙Rinse‎the soybe‎a ns and soak for about‎8 hours‎or overn‎i ght. Rinse‎the soake‎d soybe‎a ns again‎with water‎. Some manuf‎a ctur‎e rs of soy milk maker‎s claim‎that their‎machi‎n e can make soy milk direc‎t ly from unsoa‎k ed soybe‎a ns. Howev‎e r, the taste‎will not be that good and yield‎will be lower‎.∙Put the soybe‎a ns in filte‎r cup and month‎it in the soy milk maker‎.∙Add cold water‎in the conta‎i ner of the soy milk maker‎. Norma‎l ly the desir‎e d level‎s are marke‎d on the insid‎e or outsi‎d e of the conta‎i ner.∙Plug the power‎cord in and press‎the start‎butto‎n. The soy milk maker‎will first‎heat the water‎to about‎80 degre‎e C (180 degre‎e F) and then start‎to grind‎thesoybe‎a ns.∙After‎about‎15 minut‎e s the soy milk maker‎will indic‎a te that the cycle‎is compl‎e ted and that you can pour the soy milk in anoth‎e r conta‎i ner. The pulp, orokara‎, which‎remai‎n s in the filte‎r cup can be used as an healt‎h y ingre‎d ient‎in bread‎or soups‎. This okara‎is very rich in fibre‎but will also conta‎i n other‎healt‎h y ingre‎d ient‎s such as soy prote‎i n, isofl‎a vone‎s, sapon‎i ns and vitam‎i ns.Soy Milk Maker‎s at Facto‎r y-Direc‎t Price‎sGet nutri‎t ious‎non-dairy‎milks‎from harve‎s ts of the natur‎e: Beans‎, nuts, seeds‎, and grain‎sMemor‎i al Day Sale!! Ends May 20th!SoyaJ‎o y is the origi‎n al soy milk maker‎. It has won all head-to-head tests‎condu‎c tedbut impor‎t ant impro‎v emen‎t s so that SoyaJ‎o y and the SoyaP‎o wer soymi‎l k maker‎s stay ahead‎of the compe‎t itio‎n. Now we are intro‎d ucin‎g our SoyaJ‎o y G3, the third‎gener‎a tion‎of our award‎-winni‎n g SoyaJ‎o y Soy Milk Maker‎s.The SoyaP‎o wer Plus Soy Milk Maker‎is the most revie‎w ed soy milk maker‎s and the only one with an avera‎g e of 5-Star ratin‎g by Amazo‎n as of Dec. 22, 2011. It is also inTop-10 list, toget‎h er with such names‎as Kitch‎e nAid‎ Artis‎a n Serie‎s Mixer‎,and Zojir‎u shi Rice Cooke‎r. Not a singl‎e other‎brand‎of soy milk maker‎s has made it to even in the Top-100 list!We recom‎m end that you consi‎d er the follo‎w ing when makin‎g your purch‎a se decis‎i on:1. Make sure the soymi‎l k maker‎is UL liste‎d. UL has stric‎t requi‎r emen‎t s for produ‎c tdesig‎n and manuf‎a ctur‎i ng proce‎s s. It is no surpr‎i se that knock‎o ff manuf‎a ctur‎e rs can't meet UL quali‎t y and safet‎y requi‎r emen‎t s.2. Makin‎g soymi‎l k from soake‎d soybe‎a n is more healt‎h ier. Read why3. Pay atten‎t ion to the capac‎i ty of the machi‎n e - how much soymi‎l k it makes‎in one batch‎.4. Caref‎u lly read the featu‎r es of the soymi‎l k maker‎.5. Consi‎d er shipp‎i ng cost and warra‎n ty cost as part of total‎cost.6. Check‎out how long has the brand‎and the compa‎n y been aroun‎d. We have seen so many soymi‎l k maker‎brand‎s and marke‎t ers come and go over the years‎, you don't want to see the compa‎n y is alrea‎d y gone when you need their‎servi‎c e.You can find just about‎anyth‎i ng on soy milk, tofu, and soy milk maker‎s at this web site. Check‎out the subje‎c ts in the menu bar at the right‎.Featu‎r es and benef‎i ts of SoyaJ‎o y/SoyaP‎o wer soy milk maker‎sClick‎the pictu‎r e of each model‎to see more detai‎l s∙Micro‎p roce‎s sor-contr‎o lled‎cooki‎n g; no "beany‎" taste‎!∙Easy to use - add water‎and soybe‎a ns, press‎one butto‎n!∙Fully‎autom‎a tic plus manua‎l setti‎n gs for maxim‎u m flexi‎b ilit‎y, such as makin‎g raw milk (no heati‎n g), see detai‎l s of each model‎.∙Stain‎l ess steel‎const‎r ucti‎o n - lasti‎n g quali‎t y!∙Six-glass‎, 1.5-liter‎(50 oz) capac‎i ty - 6 glass‎e s in one batch‎!∙The best machi‎n e, best servi‎c e - read indep‎e nden‎t revie‎w s!∙90-day full refun‎d retur‎n polic‎y. One-year warra‎n ty!∙UL appro‎v ed with all safet‎y featu‎r es built‎into the machi‎n e.∙Five-year warra‎n ty on grind‎i ng blade‎and pitch‎e r!∙Free recip‎e bookl‎e t, clean‎i ng kit, sampl‎e soybe‎a ns,and more.About‎SoyaP‎o wer Plus:From the compa‎n y that pione‎e red soymi‎l k maker‎s with the best-selli‎n g SoyaJ‎o y soy milk maker‎comes‎this newes‎t, third‎-gener‎a tion‎milk maker‎! "SoyaP‎o wer Plus offer‎sa revol‎u tion‎a ry leap in milk makin‎g techn‎o logy‎" revie‎w ed by Vicki‎l ynnHaycr‎a ft Click‎to read full revie‎w.The only milk maker‎with four push-butto‎nopera‎t ions‎, each optim‎i zed for makin‎g milk from soybe‎a ns, grain‎s, seeds‎or unlim‎i ted combi‎n atio‎n s of beans‎, grain‎s and seeds‎.SoyaP‎o wer Plus is the most advan‎c ed and versa‎t ile milk maker‎today‎. It boast‎s thequiet‎e st opera‎t ion and highe‎s t energ‎y effic‎i ency‎thank‎s to its therm‎o-plast‎i c outli‎n erover the stain‎l ess steel‎body. With uniqu‎e safet‎y featu‎r es such as safet‎y latch‎andtherm‎o-isola‎t ion, the SoyaP‎o wer Plus is about‎the only UL appro‎v ed filte‎r-lesssoymi‎l k maker‎on the marke‎t. The SoyaP‎o wer Plus gets the highe‎s t user ratin‎g. Click‎here for detai‎l ed revie‎w s of SoyaP‎o wer Plus soy milk maker‎.The Torna‎d o Grind‎i ng Syste‎m (TM) enabl‎e s not only the highe‎s t milk yield‎andeasie‎s t soymi‎l k makin‎g opera‎t ion avail‎a ble, but also the capab‎i lity‎for makin‎gnon-dairy‎milks‎and porri‎d ges from any type of beans‎, rice, grain‎s, seeds‎and nuts,such as soybe‎a ns, mung beans‎, brown‎rice, white‎rice, oats, mille‎t, wheat‎groat‎s,almon‎d s, hazel‎n uts, hemp seeds‎, or any combi‎n atio‎n s of them. It can even makebroth‎s and soups‎like soy-pumpk‎i n soup and rice and sweet‎potat‎o es soup.For more detai‎l s, click‎the SoyaP‎o wer Plus pictu‎r e, or click‎hereSanli‎n x Retur‎n/Refun‎d Polic‎yAs the exclu‎s ive US whole‎s ale distr‎i buto‎r, Sanli‎n x Inc. will provi‎d e its custo‎m ers with warra‎n ty servi‎c e even if the SoyaJ‎o y is purch‎a sed from our resel‎l ers, provi‎d ed that the warra‎n ty is regis‎t ered‎with Sanli‎n x withi‎n 30 days of purch‎a se. If you buy the SoyaJ‎o y from a SoyaJ‎o y resel‎l er, the resel‎l er may have its own retur‎n and refun‎d polic‎y, in which‎case the resel‎l er must be conta‎c ted for retur‎n/refun‎d.If this same machi‎n e is sold with a resel‎l er's own brand‎, Sanli‎n x is NOT respo‎n sibl‎e for retur‎n/refun‎d or warra‎n ty servi‎c e. Refun‎d Polic‎y豆浆机来自Wik‎ipedi‎a,免费百科全‎书例如，众多不同种‎类的豆浆机‎制造商之一‎豆浆机是一‎种小的厨房‎设备用于自‎动研磨豆浆‎，是一种用黄‎豆制成的非‎乳制品家用‎电器。

洗衣机毕业设计外文翻译

Washing machinesLet’s look inside one of today’s fully automatic washing machines that use swirling water to clean the clothes. There are many types of washing machines but this Figure shows you what most of them are basically made up of.。

The reason why a washing machine like this can wash and get the water out of the clothes at the same time is because it has a double layer drum. When washing and rinsing, the pulsator spins and makes the water swirl.. To get the water out of the clothes, the inner wall f the drum spins and the water goes through the holes.These days, the “centrifugal force washing machines” are quite popular. This type of machine does not use a pulsator. Instead, the inner wall spins really quickly. When the drum spins, the dirty clothes get stuck to the wall. The water and detergent also try to escape through the holes of the wall but before they do so, they are forced to escape through the clothes. When this happens, the power of the water and detergent removes the dirt form the clothes. Another good thing about this type of machine is that clothes don’t get tangled up so you don’t have to worry about your clothes getting ripped or damaged.Next, let’s look at some different types of washing machines!Many of you probably think that the water inside washing machines goes round and round. Actually, different washing machines make water flow in different ways.Whirlpool type:This type of washing machine uses a pulsator to force the water to move like a whirlpool inside the Drum. The spinning water forces the dirt out form the clothes inside the machine. Some of the newer models of this type also make the whirlpool move up and down to make it clean clothes even better!Agitator stirring typeThis type of washing machine has something that looks like a propeller at the bottom of the tub.This Propeller spins around and stirs the water. The water then forces the dirt out from the clothes in the machine. The good thing about this type of machine is that clothes do not get tangled up and clothes get evenly washed.Drum type:This type of machine has a drum with many holes in it. There are also protrusions bumps on the wall of the drum. As the drum turns, the clothes are picked up by the protrusions. When the clothes fall down from the top of the drum through the water, the movement removes dirt from the clothes.Centrifugal force type:As we have said before, the spinning drum pushes the water and detergent out through the wall of the inner drum. The power that comes form spinning the drum is called centrifugal force., which is where the name comes from. The water is forced through the clothes and then the holes in the inner wall. After one cycle, the water is recycled back into the tank and the process starts again. This cycle is what cleans the clothes!In Japan, people first started using machines in 1930. But then the price of a washing machine was so high that most average persons could not buy one for their homes.Looking back now, there was something strange and funny on some of the first versions of the washing machine .The machine had two rollers that were used to sandwich each shirt and other clothes to squeeze the water out of them. The rollers were turned by hand, and in fact, you needed a lot of strength to turn those things! Still, people then thought it was a really neat invention! This type of water squeezer was used for almost 30 years until something new came along. The spin drier that used “centrifugal force” to get most of the water is out of the clothes.In 1953, the nozzle type washing machine was first sold in Japan. This washing machine is like the older brother of the swirling washing machine that you see today. The price of these washing machines was lower and because of this, more people bought them. The first fully automatic washing machine was introduced in 1968, and after that, washing clothes became a lot easier to do!There are a lot of different types of washing machines. What kind of washing machine do you have in your house?Fully automatic:The fully automatic machine has two drum layers that wash, rinse and remove water from clothes together. All you have to do is add detergent and put in dirty clothes and then washing machine will do the rest. There is also a new type of fully automatic washing machine that can dry clothes after they have been washed.Twin tub:This washing machine has one part that dose the washing and another part that does the squeezing. Even though it’s a hassle to take the clothes out and move them to othe r tub, the good thing is that you can wash and squeeze at the same time with one machine.Front loading:The main feature of front loaders is that they use a lot less water than other types. This is the type of Washing machine that dry cleaners use but a lot of people in western countries have this type of washing machine in their homes too.Let’s try to make the best washing machine in the world!We should already thank the scientists that invented the fully automatic washing machine because it makes washing clothes a piece of cake.Scientists are still trying really hard to find ways to make washing machines a lot handier to use for everyone. Some of the things that they are trying to do are to find better ways of making clothes clean and ways to make washing machines last longer. There are washing machines with d trying function today so you don’t even have to hang clothes after words because it dries them automatically! Amazing!Scientists are also trying to find ways to use less water and less detergent in washing machines at present. This is because that it is better to use less water for preserving the environment.What are washing machines of the future going to be like? Maybe there will be a washing machine that dries and folds your clothes after washing them, or maybe there will be one that will wash your clothes while you are still wearing them! How handy would that be! Remember, if the first washing machine was like a dream to people in the old days, all the dreams you have about washing machines of the future may come true!Now, washing machine is becoming more and more popular. We see the main classification.Washing machine can be divided into automatic type and semi-automatic type two kinds, automatic type washing machine as long as we begin our work proactively set better washing procedure, washing machine began to work until the end without manual intervention. Andsemi-automatic washing machine washing and dewatering process is divided, is also called the double barrel washing machine, a tong, one takes off a bucket, and put tong inside washing out to artificial add to take off in the barrel dehydration is handled and complete laundry process.Full-automatic washing machine in structure to take off in tong internal bucket suit, two barrels of axis, while working with the clutch to finish washing state and dehydration of the transition of the states, on the key said is automatic washing machine.Full-automatic washing machine press catharsis means to points, can be divided into bunt washer and roll barrel type two kinds of washing machine, From the electric control ways to points, can bedivided into mechanical program-controlled type and computer board controls type washing machine two kinds.The cylinder and the pulsator washing machine are now the main two kinds.Pulsator washing machine working principle is to add clothing, then open the inlet valve, choose good bibcock of water level and correct working procedures, switch on the power, closed warehouse door, and safety switch closed at water level, the public internal switch contacts are and dehydration contacts are interlinked, inlet valve electrify water, when the barrel water reaches the specified height, in air pressure under the action of water level switch inside public contacts disconnect dehydration contacts and connect washing contacts, feed valve power to stop water, motor power is switched on, motor started running, and periodically sometimes are turning, sometimes reverse, mutual alternant, driven by clutch BoLun using the same cycle are turning, inversion, with a certain speed rotating BoLun can drive inside bucket of water and clothing, clothing rotating water formed in the mutual friction and reach the purpose of laundry. When washing process is completed, drainage electromagnetic valve electrify work, drain valve is opened, inside bucket of water exudes, and linkage shaft also the clutch from washing state switch to dehydration state, when drainage is completed, atmospheric pressure drop and inside bucket of water level switch public contacts reset through dehydration contacts, drainage electromagnetic valve keep electrify state, motor driven off running electrify bucket high-speed and jilt dry clothing, laundry program after washing machine disconnect hydropower and stop. As for intermediate process of how many times, laundry to wash the length of time, by process control.Roller-type washing machine of the principle and Pulsator washing machine are basic similar. But 110mm drum machine it no clutch variable speed, but its motor is double-speed motor, so when washing machine work in washing state, program-controlled device connected motor washinglow-speed windings, motor speed slow, working on dehydration, when they connect dehydration modal high-speed windings, motor high-speed operation, this process is programmed through the device and motor to work together to finish.To sum up, the role of these two kinds of washing machine is same, but different implementation, each has his strong point, Pulsator washing machine is simulated handmade kneaded action to work, 110mm drum type washing machine is by gravity inertial function to finish our work, they realize washing and dewatering way also have different features, Pulsator washing machine to wear clothes is relatively large, but detergents degree is higher, 110mm drum machine for clothing wear small, but detergents degrees, but lower than Pulsator washing machine to save water.So far, washing machine is still towards a higher requirements development.译文：洗衣机来看一下涡流式全自动洗衣机的构造。

电子商务网络安全毕业设计英文原文及翻译-论文[管理资料]

电子商务网络安全毕业设计英文原文及翻译-论文电子商务网络安全毕业设计英文原文及翻译|计算机专业全套免费毕业设计论文网|任务书|本科毕业设计课题目作品下载附录Ａ---英文原文Web Security Privacy & CommerceThe running battle between hackers and network security professionals has moved beyond the perimeter firewall to hand-to-hand combat at individual Web and corporate servers．And new security weapons have emerged that use ingenious methods to protect Web sites and corporate networks from external and internal security threats．Here are some of the latest tools at your disposal.No exitGillian G-Server doesn’t care how the hacker got in or what changes they may have made to your Web site．Gillian Exit Control technology prevents the world from seeing the consequences of a security breach．Gillian G-Server sits between the Web server and the router or firewall that connects the Web server to the Internet, inspecting every piece of content that goes out. The Exit Control G-Server contains a collection of digital signatures made from authorized Web content during the publication process．Each time the site content producers publish a new or revised object，the G-Server saves a digital backup of the object along with a digital signature.Signatures that don match send up a red flag which triggers the G-Server to immediately replace a bogus page with a secure archived copy of the original，while simultaneously alerting appropriate personnel．Tripwire，Inc. Tripwire for Servers is a similar data and network integrity product．However，Tripwire for Servers takes a different approach ——its software is loaded onto the server that you want to protect．It monitors all file changes，whether they originate from inside or outside the company，and reports back if a change violates predetermined policies.Honeypots or decoysHoneypots are designed to lure and contain an intruder on the network．Honeypots are decoy devices that can divert attacks from production systems and let security administrators study or understand what happening on the network．ManTrap，from Recourse，is a powerful honeypot that deployed next to data servers，if it being used to deflect internal attacks，and located off the firewall in the demilitarized zone (DMZ) if it being used against external threats．The majority of users deploy it internally to get suspicious activity under control.In that scenario，a ManTrap server would be set up to look like a file server that stores intellectual property or business plans．A successful deployment of ManTrap depends on a variety of factors including quality，naming scheme，placement and security policy．For example，deceptive defenses are most effective when deployed in quantities equal to or greater than that of the production system．Honeypots can get expensive which is why companies must pick and choose the critical servers they want to protect.What attracts an attacker to ManTrap is configuring it to make it look more vulnerable than other servers．Once the hacker is on the decoy server，security managers can log the hacker activity and gain insight into what the intruder is trying to accomplish. Fall into the gapAir gap technology provides a physical gap between trusted and untrusted networks, creating an isolated path for moving files between an external server and a company internal network and systems. Vendors include RVT Technologies, Spearhead Technology and Whale Communications.Whale e-Gap Web Shuttle is a nonprogrammable device that switches a memory bank between two computer hosts. The e-Gap Web Shuttle creates an air gap between the Internet and a company back-office systems. Companies might use e-Gap Web Shuttle between an external service running e-commerce applications, such as online banking, and internal databases that might be queried by external users.The e-Gap system consists of the e-Gap appliance that is attached to two PC hosts, one internal and one external. The internal host connects to the company internal network and the external host sits in the DMZ in front of the firewall.All URLs to Web pages are directed to a mock location on the external host. Pages do not actually reside on this host. The external host strips off the protocol headers, extracts only the content of the Secure Sockets Layer (SSL) traffic and passes it to the e-Gap Web Shuttle. The e-Gap Web Shuttle transports the encrypted data to the internal host using a toggling e-disk. The e-Gap internal host decrypts SSL traffic, authenticates the user and filters the URL content. It then passes the URL request to the company production Web server that resides on the back-office network.The fix is inSecurity and vulnerability assessment tools, designed to be used in-house, can detect weaknesses in an organization systems before problems occur and can fix those problems.Retina , from eEye, scans, monitors, alerts and automatically fixes network security vulnerabilities. The product works on Windows NT SP3 or higher and Windows 2000.The software is installed on any machine within the network. The network administrator types in a range of IP addresses to scan and pushes a button. The product scans the network for vulnerabilities, software flaws and policy problems and reports any vulnerabilities.The product “fix it” feature provides network administrator with a description of any found vulnerabilities, information on how to fix it, or access to a fix it button that can repair the vulnerability locally or remotely.Demolishing DoS attacksPerhaps one of the newest categories of security is products that target denial-of-service (DoS) attacks and more. By definition, DoS attacks make computer systems inaccessible by exploiting software bugs or overloading servers or networks so that legitimate users can no longer access those resources. The product category is so new that some products are still in beta test or on the cusp of entering the marketplace. Going after one of the most malicious types of computer vandalism, the DoS attack, are Arbor Networks, of Waltham, Mass.; Mazu Networks, of Cambridge, Mass.; and Asta Networks in Seattle.Mazu’s solution to distributed DoS attacks works via intelligent traffic analysis and filtering across the network. A monitoring device, such as a packet sniffer or packet analyzer, evaluates packets on the network at speeds up to 1G bit/sec. A monitoring device then determines which traffic needs to be filtered out.The good, the bad and the uglyThe good news about all of these new security techniques is that they theoretically offer companies additional layers of security protection, providing better overall security. What this ultimately means to businesses is that additional security mechanisms can succeed where others have failed. Another plus about some of the new products is that they are optimized for a particular application, such as integrity of the Web servers.However, as with any technology, there are pros and cons to consider. In fact, there are some downsides to implementing these new security products. For example: They are all incremental solutions, not replacements.They require a certain amount of expertise.Many vendors are start-ups and there a risk as to how long theyl be around.There a concern, in many IT shops, about adding preventive controls because of associated overhead——a concern that can be easily remedied by investing in additional horsepower.What too much? When does a company run the risk because of having too many products to manage?The bottom line is that security is never a done deal. It a continuing process that a new crop of innovative vendors are making more interesting.Benevolent WormsAlthough the prospect of using virus technology to simplify the task of delivering patches and software updates is tempting, the dangers can outweigh the benefits when the process is too automated. For example, the improved Windows Update feature in Windows XP now allows patches and updates to be downloaded automatically,altho ugh installation is still at the user’s discretion.Trojan horses, worms, and other malicious code forms have proven to be incredibly successful at paralyzing e-mail systems and Internet providers. It is therefore only logical to conceive of ways to use them for productive purposes, much as the Bible exhorts its readers to beat their swords into plowshares and their spears into pruning hooks.Granted, it would be wonderful if IT administrators could distribute patches and software updates to desktops and servers as quickly as an e-mail virus can spread from one machine to the next. But is such a magic wand really a good idea?Well, maybe not exactly. After all, unlike the human immune system, which produces defenses, or antibodies, automatically, the computer must wait for a human to analyze samples of a computer virus, prepare antidotes and vaccines for that specific situation, and only then apply the cure.This observation alone would seem to discredit the idea of a “digital immune system” that the sec urity community has tossed around during the past few years, but there’s an even more important point to consider. Similar to the way that autoimmune diseases turn the body’ s own defenses against itself, so could one turn a viruslike software delivery system against its own computers. Although it would be difficult to monkey with the digital certificates that would conceivably be used to identify trusted patches, it’s not impossible to subvert the certificate issuing system, as Microsoft and VeriSign found to their dismay last March.Ultimately, a viruslike software delivery system would require software publishers to deliberately put a back door into their systems, and few customers will tolerate that practice, even under shrinkwrap licensing terms. Becau se there’s no guarantee thatsuch a tempting target wouldn’t be exploited by hackers, any IT manager deploying such a system would be foolhardy in the extreme.Virus behavior that standpoint go to see from the operate system, is some normal behaviors, and say for the operate system that don't break the law , therefore at kill the virus software to check to kill the virus, usually meeting because operate system of obstruction-" the document was take upped by system and can't change the code at system "," virus the inside to circulate" etc. reason, but can't clean the virus , we at kill the virus of time also want to speak to investigate some techniques, and go to the round over the operate system's obstruction, from success of virus is from the system Speak here of kill the virus method is:Kill the virus with the tool under the safe mode to kill the virus under the pure DOS mode.Why want the pure DOS mode to down kill the virus?Because the virus procedure is under the operate system explain the mode to circulate o, such as:Script virus" new and happiness time", virus etc., they can't circulate in the inside memory, and system also argue all legal procedures but as to it's take in to protect, and guarantee it continue to circulate, prohibition against in the movement procedure right proceed modification, this result ined virus can't quilt the clearance's result for aegis for having under the pure DOS mode, connecting the Windows operate system all don't can quilt circulating, virus more impossible movement, for this reason this hour as to it's checking killing, round over system, attaining cleanly killing the virus.The usage special tool under the safe mode to kill the virusThe each of Windows operate system for edition all contain a safe mode to circulate the way, and here circulate the way bottom can only circulate the most basic procedure, again this mode bottom, you can cancel all of from start the item,avoid the virus's special tool is small and very shrewd, and use it can under the safe mode normal weakness is a result for can aim atting the popular virus of some comparisons, can't attaining completely killing the virus.For attain to kill the clean virus result, we can synthesize to use these two kinds of methods.Kill the virus not equal to defend the virus, and hard work should be protected . Privacy-Protecting techniquesIn this chapter, we will look at some proven techniques to protect your privacy when you use the Internet. Most of these techniques are simple, commonsense rules that you can put into effect immediately-choosing a good service provider, using good password, cleaning up after yourself online, avoiding Spam and junk email, and protecting yourself from identity theft.Choosing a good service providerThe first and most important technique for protecting your privacy is to pick service providers who respect your privacy.Here are some things to consider when you choose an ISP:. Unless you take special measures to obscure the content and destinations of your Internet usage, your ISP can monitor every single web page that you visit, every email message that you send, every email message that you receive, and many others about your Internet usage.. If you have a dialup ISP ,your ISP can also infer when you are at home ,when you go on vacation, and other aspects of your schedule.. If you check your email from work ,your ISP can learn where you work.. Many ISPs routinely monitor the actions of their subscribers for the purposes of testing equipment, learning about their user population, or collecting per-user demographics.. Some ISPs will monitor the web sites that you visit and sell this information for the purpose of increasing their revenue. In some cases, the ISPs clearly state this policy and, in fact ,use the sale of the data as a way of subsidizing the cost of Internet access .Other ISPs silently engage in this practice.. Equipment is now on the market that allows ISPs to monitor the advertisements that are downloaded to your computer and ,in some case, replace the advertisements with different ones. This equipment is also capable of generating detailed user-level statistics.. Some ISPs have strict policies regarding which employees have access to user data and how that data must be protected .Other ISPs have no policies at all.. Many policies that are in use basically say “we can monitor anything that we want.”However,not all ISPs that have these policies actually monitor their users. Picking a Great PasswordPasswords are the simplest from of authentication. Passwords are a secret that you share with the you log in, you type your password to prove to the computer that you are who you claim to be. The computer ensures that the password you type matches the account that you have specified. If they match, you allowed to proceed.Using good passwords for your Internet service is a first line of defense for your privacy. If you pick a password that is easy to guess, then somebody who is targeting you will find it easier to gain access to your personal information. If you use the same password on a variety of different services ,then a person who is able to discover the password for one of your services will be able to access other services.Good Passwords: locked DoorsGood passwords are passwords that are difficult to guess. The best passwords are difficult to guess because they:-Have both uppercase and lowercase letters-Have digits and/or punctuation characters as well as letters-May include some control characters and /of spaces-Are easy to remember, so they do not have to be written down-Are at least seven of eight characters long-Can be typed quickly ,so somebody cannot determine what you type by watching over your shoulderIt is easy to pick a good password. Here are some suggestions:.Take two short words and combine them with a special character or a number, like robot4my or eye-con..Put together an acronym that is special to you, like Notfsw(None of this fancy stuff works),auPEGC(All Unix programmers eat green cheese),orTtl*Hiww(Twinkle,twinkle,little star. How I w onder what…).Cleaning Up After YourselfWhen you use the Internet, you leave traces of the web sites that you visit and the information that you see on your computer. Another person can learn a lot about the web sites that you have visited by examining your computer for these electronic footprints. This process of computer examination is called computer forensics, and it has become a hot area of research in recent years. Special-purpose programs can also examine your computer and either prepare a report, or transmit the report over the Internet to someone else.Although it can be very hard to remove all traces of a web site that you have seen or an email message that you have downloaded, you can do a good job of cleaning up your computer with only a small amount of work. There are also a growing number of programs that can automatically clean up your computer at regular intervals as we will see in the next chapter.Avoiding Spam and Junk EmailUnwanted electronic mail is the number one consumer complaint on the Internet today. A 1999 study by BrightMail,a company that develops antispam technology, found that 84 percent of Internet users had received Spam;42 percent loathed the time it takes to handle Spam;30 percent found it to be a “significant invasion of privacy;”15 percent found it offensive; and ISPs suffered account churn rates as high as percent as a direct result of Spam.Protect Your Email AddressTo send you junk mail, a spammer must have your email address. By understanding how spammers get email addresses, you can keep your mailbox relatively Spam-free: Do not put your email address on your home page, Take your name out of online directories, Do not post to public mailing lists, Do not post to Usenet, Pick an unusual username.附录Ｂ---中文翻译网络上的个人和商业安全原文见于，请对照参考。

毕业设计英文翻译中英文对照版

Feasibility assessment of a leading-edge-flutter wind power generator前缘颤振风力发电机的可行性评估Luca Caracoglia卢卡卡拉克格里亚Department of Civil and Environmental Engineering, Northeastern University, 400 Snell Engineering Center, 360 Huntington A venue, Boston, MA 02115, USA美国东北大学土木与环境工程斯内尔工程中心400，亨廷顿大道360，波士顿02115This study addresses the preliminary technical feasibility assessment of a mechanical apparatus for conversion of wind energy. 这项研究涉及的是风能转换的机械设备的初步技术可行性评估。

The proposed device, designated as ‘‘leading-edge-fl utter wind power generator’’, employs aeroelastic dynamic instability of a blade airfoil, torsionally rotating about its leading edge. 这种被推荐的定义为“前缘颤振风力发电机”的设备，采用的气动弹性动态不稳定叶片翼型，通过尖端旋转产生扭矩。

Although the exploitation of aeroelastic phenomena has been proposed by the research community for energy harvesting, this apparatus is compact, simple and marginally susceptible to turbulence and wake effects.虽然气动弹性现象的开发已经有研究界提出可以通过能量采集。

本科毕业设计翻译英文

( 1. Faculty of Civil Engineering & Geosciences, Delft University of Technology , P. O. Box 5048,2600 GA Delft, t he Nether lands; 2. Key Laboratory of Silicate Materials Science and Engineering of the Ministry of Education, Wuhan University of Technology, Wuhan 430070, China)Abstract: Coal tar, a by- product from the destructive distillation of coal in co king oven, is widely used in road engineering for its excellent adhesion and fuel resistance properties, especially for pavement surface treatments in gas stations and airports.However, coal tar has a high Poly cyclic Aromatic Hydro carbons ( or PAHs) content, which makes it toxic.I n 1985, the International Agency for Research on Cancer ( IARC) has proved that coal tar is carcinogenic to humans. Research showed that Coal Tar- based Sealers ( CTS) contribute to the majority of PAHs pollution in the water environment. Because of this environmental concern, CT S are not allowed in many dev eloped countries in the USA and Europe. In contrast, coal tar is still used for road engineering in China and is even used increasingly .This paper gives a literature review on the general information and research about environmental concern of using coal tar in road engineering. Based on the review , some possible alternatives to replace coal tar are described. These alternatives include nanoclay/ epoxy modified bitumen/ bitumen emulsion and waterborne polyuret hane/ epoxy resin, which are environmental friendly. They have the potential to perform as w ell as CTS, and even better in some special applications.Key words:coal tar; pavement surface treatment; adhesion property; poly cyclic aromatic hydrocarbons; modified bitumen emulsionCLC number: U 416 Document code: A Article ID: 1671- 4431( 2010) 17- 0001- 07Received date: 2010- 05- 07.Biography : Xiao Y( 1986- ) , Ph D Candidate. E-mail: yue. xiao@1 introductionTwo basic types of binders are currently used in the pavement surface treatment market: coal tar-based and bitumen-based. At some places like g as stat ions and airports, coal tar-based surface sealers performed much better than bitumen-based sealers with regards to adhesion properties and chemical resistance. Coal tar-based have better resistance to petroleum oils and inorganic acids, and have better moisture resistance[ Austin, 2005] .Because of these out standing properties, CTS are widely used in road engineering for pavement surfacetreatment for many years. However, coal tar is a complex hydrocarbon mixture consisting of hundred of PAH[SCHER, 2008] . These PAHs are toxic and considered human carcinogens. Because of it s environmental unfriendly properties, coal tar is not allowed in most of the developed counties like the Netherlands. In the Netherlands,use of tar containing product s is not allowed since 20 years, with one temporary except ion for antiskid runways in airfields [ van Leest , 2005] . But after 2010, it w ill not be allowed for airport pavement application anymore. Compared to these bans, coal tar is still used for road engineering in China. China Coal Tar Industry Report mentioned that the coal tar consumption w ill be on the upward t rend [CCTIR, 2008] .Based on new technologies like nano technology and two-component technology, other materials are developed for pavement surface treatment and they perform w ell. Modified bitumen emulsions, which can be applied at low temperatures, were successfully used in South Africa, Australia and many other countries. Additives such as polymers ( SBS, SBR and EVA ) , clays ( illite, kaolinite and montmorillonite ) are known to improve the properties of bitumen emulsions in special road applications [ TRB-EC102, 2006;Xiao, 2010] . With the waterborne two-component technology, coating manufacturers can producehigh-performance sealers and achieve the same or better properties than solvent-based sealers. Furthermore, waterborne resins for coating s usually do not contain or just contain a small amounts of other solvent s, indicating that waterborne two component systems are environmental friendly. Epoxy modified bitumen w as originally developed in the late 1950s by Shell Oil Company as a material designed to withstand fuel exposure [ Thom, 2006] . After full curing , epoxy modified bitumen mixture has high temperature stability and strength, excellent fatigue, superior adhesion and rutting resistance.In this paper, a short literature review is given on the use and properties of CTS for pavement surface treatment and its environmental concern. After that several possible alternatives are discussed, such as nanoclay modified bitumen emulsion, epoxy modified bitumen, waterborne polyurethane/ epoxy resin. These alternatives may have good properties and are environmental friendly.2 Use and Advantages of Coal Tar Based SealersCoal tar-based products are used in many industries, for example pavement engineering, the building industry and medical treatment s. In pavement engineering , one of the largest applications is CTS.Coal tar can be used as a binder and filler in surface treatment formulations, and as a modifier for epoxyresin surface coating s. T he streets of Baghdad w ere the first to be paved with tar from the 8th century AD. Tar was a vital component of the first sealed, or tarmac roads. The first tar macadam road with a tar-bound surface was placed in 1848 out side Nottingham, England. In Washington D. C. some of thetar-bound surface courses have a service life of about 30 years.Coal tar is a very complex mixture of chemicals. It s molecular structure is quite different from bitumen.Some of the constituents are described as PAHs. Being stable in molecular structure, these chemicals are incompatible with oil and gas, and provide a barrier coat to protect asphalt surfaces against the destructive effects of petroleum based products and chemicals [Aust in, 2005] . CTS have a better chemical resistance than bitumen based, extremely low permeability to moisture and a high resistance to ultraviolet radiation. These properties make it ideally suited for parking areas w here concentrations of oil and gasoline leaks are prevalent, like gas stations, truck and bus terminals and airport s. CTS are used to extend the life and reduce maintenance cost associated with asphalt pavements, primarily in asphalt road pavement. They are typically used at airports for aprons, taxiways and runways. The Federal Aviation Administration Advisory Circular 150/ 5370-10A Standards for Specifying Construction of Airports include a requirement for pavement sealers that they should contain at least 35% coal tar in runway asphalt pavement.The reason for this requirement is that CTS have a much better resistance to jet fuel than bitumen-based sealers [Austin, 2005].3 Environmental ConcernGenerally, coal tars consist of a mixture of many organic compounds, like benzene, toluene, phenol, naphthalene, anthracite , and others. The risk assessment of coal tar is largely based on PAHs, especially on Benzo (a) pyrene . PAHs are the most relevant component s in terms of toxicity in coal tarproducts[ SCHER, 2008] .3. 1 Polycyclic aromatic hydrocarbonsPolycyclic aromatic hydrocarbons are also known as polycyclic aromatic compounds, polyaromatic hydrocarbons or as polynuclear aromatics. PAHs are a group of over 100 different chemicals consisting of carbon and hydrogen in fused-ring structures. T able 1 shows several typical chemical structures of PAHs. PAHs are highly toxic and harmful to human and ecosystem health [Austin, 2005] . The content of PAHs in coal tar increases as the carbonization temperature increases.3.2 Environmental riskIn 1985, IARC has pointed out that coal tar pitches are carcinogenic in humans [IARC, 1985] . In 2008,three scientific commit tees ( SCCP, the Scientific Commit -tee on Consumer Products; SCHER, the Scientific Committee on Health and Environmental Risks; SCEN IHR, the Scientific Commit tee on Emerging and NewlyIdentified Health Risks) concluded that cancer risk was the most serious point of coal tar s risk characterizations [ SCHER, 2008] . Occupational exposure to coal tar increases the risk of developing skin cancer and other tissue sites , like lung, bladder, kidney and digestive tract . According to the IARC, products that include more than 5 percent of crude coal tar are Group 1 carcinogen which has sufficient evidence of carcinogenicity in humans. So, many countries all over the world have eliminated it s usage.In 2003, scientist s from the city of Austin ( USA ) identified CTS as a significant source of PAHs contamination. The United States Geological Survey and Austin City have conducted additional research that corroborates this finding, concluding that coal tar sealants are responsible for the majority of PAHs pollution in water environment in the Austin area. Coal tar-based pavement sealers are considered as a source of urban water pollution. These are long-lasting substances that can build up in the food chain to harmful levels to humans. Based on their investigations, Austin became the first city in the USA to ban the use of CTS for pavements [ Austin,2005; Mahler, 2005] .As a precaution, in Germany, manufacturers have voluntarily agreed to ban coal tar from their product s. In the Netherlands, coal tar containing products did not meet the Dutch Environmental Standards and w ill not be allowed for airport pavement after 2010.4 Possible AlternativesAccording to these environmental concerns, alternatives are required. These alternatives should have atleast comparable or better properties than CTS. At the same time, they should be environmental friendly. In this section, the possible use of modified bitumen emulsions, epoxy modified bitumen and waterborne resins are discussed.4. 1 Modified bitumen emulsionsBitumen emulsions are heterogeneous systems with two or more liquid phases, consisting of a continuous liquid phase ( water ) and at least one second liquid phase ( bitumen) dispersed in the former as fine droplets [ TRB-EC102, 2006] . Standard bitumen emulsions are normally considered to be of the oil in water type and contain from 40% to 75% bitumen, 0. 1% to 2. 5% emulsifier, 25% to 60% water plus some minor components. The bitumen droplets rang e from 0. 1 to 20 micron in diameter.4. 1. 1 Properties of modified bitumen emulsionsUnlike bitumen, bitumen emulsions do not need to be heated at high temperatures before application. Temperature storage and application at ambient temperature can avoid the use of energy and emissions associated with heating and drying [Kennedy, 1997]. This makes bitumen emulsions more economic and environmental friendl , compared to coal tar-based products.Additives are used to improve the properties of bitumen emulsions in special road applications. Polymer( SBS, SBR and EVA) , clay illite , kaolinite and montmorillonite and epoxy modified bitumen/ bitumen emulsions were successfully used in South Africa and Australia [ TRB-EC102, 2006; Xiao, 2010] .During the application of bitumen emulsion, the water must be separated from the bitumen phase and evaporate.This separation is called breaking. After complete evaporation of the water, the bitumen particles will coalesce and bond together to develop mechanical properties. This strength development is curing.4. 1.2 nanoclay modified bitumen emulsionThe most preferred and widely used nanoclays are organically modified smectite clays with a 2: 1-type layey structure such as montmorillonite, saponite, etc [ Ammala , 2007] . All these layered silicates have the same crystalline structure and normally have a thickness of about 1 nanometer and a length of about 50 ~ 1 000 nanometers.In nanoclay modified bitumen emulsion, three possible particle dispersions can be distinguished as Fig. 1 shows [Xiao, 2010]. In the case of type one (see Fig. 1( a) ) , all the nanoclay particles are dispersed in the bitumen droplets. In this case, after breaking and curing the particles are dispersed in the binder between the aggregates. In the second type (see Fig. 1( b) ) , all of the nanoclay particles are dispersed in the water phase. After breaking and full curing, the particles are surrounding at the boundaries of the bitumen droplet s. The third type( see Fig. 1( c) ) is a combination of the first two types. Some of the particles are dispersed in the bitumen droplets while the others are dispersed in the water phase. In this condition, after breaking and curing the nanoclay particles both occur in the binder and between the bitumen droplets.These dispersion types have a significant influence on the properties of bitumen residues. Further investigations need to be carried on for checking these dispersions.Fig . 2 shows the possible outstanding properties of nanoclay modified bitumen emulsion on outside chemical resistance [Xiao, 2010] . With the unmodified bitumen emulsion after curing on the pavement surface, fuel, moisture and ultraviolet radiation can affect the binder directly. These can decrease the performance and cause raveling and ageing problems. When nanoclay modified bitumen emulsions are used for surface treatment, four steps can be dist inguished during breaking and curing. First, nanoclay modified bitumen emulsion consist s mainly of water, bitumen drop and nanoclay layers. Second, the water phase evaporates during the breaking and curing process. Then, bitumen droplets adhere to nanoclay particles, causing clusters to form the binder. At the last, binder is formed with nanoclay layers inside.The dispersed nanoclay particles can decrease surface damages due to fuel, moisture, air, etc. to a certain extent, resulting in better chemical and ageing resistance.4.2 Epoxy modified bitumensThe epoxy modified bitumen binder is a two phase chemical system in which the continuous phase is an acid cured epoxy and the discontinuous phase is a mixture of specialized bitumens, which makes the mixture performdifferent from a traditional asphalt mixture.4. 2. 1 Properties of epoxy modified bitumensEpoxy modified bitumen was used for pavement treatment long time ago and has achieved better properties than unmodified bitumen. In 1967, it was used to strengthen the surface of San Francisco Bay smile-long San Mateo-Hay ward Bridge. After more than 40 years, the bridge surface is reported to be in excellent condition.The special structure of epoxy modified bitumen makes it perform different from traditional bitumen. It does not become brittle at low temperature and does not melt at high temperature. Epoxy modified bitumen is a flexible material that can be applied in thin surface layers. When used on roads, it sets quickly enough to allow early traffic even before full curing, which enables the road to be reopened withintwo hours [ Xiao, 2010] .Epoxy modified bitumen is reported to be extremely durable as w ell as flexible. Surfaces with epoxy modified bitumen obtained better skid resistance and produce less noise than bitumen based sealers. Epoxy modified bitumen has extremely high temperature stability and strength, superior rutting resistance, excellent adhesion properties, high resistance to surface abrasion and is sufficiently fuel resistance [ Elliot t, 2008; Xiao, 2010] .4.2.2 Two-component epoxy modifiedbitumenTwo-component epoxy modified bitumen is acold mix application material. It is a two componentreactive material based on two components. One is amix of bitumen, bitumen-compatible epoxides andadditives. The other one is a mix of hardeners. After mixing of these two component s, there will be a fast react ion leading to epoxy resin within a bitumen based matrix.The tensile strength of Esha Seal 2C, which is a kind of two-component epoxy modified bitumen, obtained from ICOPAL BV, was evaluated using the Direct T ensile Test . Fig. 3 shows the tensile strengthafter different curing times and temperatures.Results indicate that the curing rate of epoxy modified bitumen emulsion depends on the curing temperature. The tensile strength increases with increasing curing time temperature . The tensile strength after full curing is higher than thetensile strength of bitumen, which implies that roads can be reopened for traffic very quickly w hen epoxy modified bitumens are applied in the surface layer.4. 3 Waterborne resinsWaterborne resins use water as the main volatile liquid component . It always shows good adhesion and the resistance to fuel, water and chemical is good. New technologies in waterborne systems provide unique technical solutions to get good properties, such as good adhesion to concrete and acidic resistance. With the waterborne two-component technology, coating manufacturers can formulate high-performance coatings without a cosolvent and achieve the same or better properties. Here waterborne polyurethane and epoxy resins will be discussed.4. 3. 1 Waterborne polyurethane resinsPolyurethane is a polymer consisting of a chain of organic units joined by urethane carbamate links. Polyurethane resins are formed from the reaction of an isocyanate with compounds containing active hydrogen, as Fig.4 shows. When the two components are mixed the hydroxyl groups ( - OH) in the resin react with the isocyanate groups ( N=C=O) in the hardener and a three dimensional molecular structure is produced[Weiss, 1997] .Because only one isocyanate group can react with one hydroxyl group, it is possible to vary the ratio of hydroxyl groups and isocyanate groups slightly either w ay in order to modify the mechanical properties of the system.Basically, waterbornepolyurethanes can be described asreactive or non-reactive polymerscontaining urethane and urea groupswhich are stabilized in water byinternal or external emulsifiers. Thesedifferent hydrophilic modify cationsallow the production of stablewaterborne polyurethanes with average particle sizes between 10 nm and 200 nm. Waterborne polyurethane resin is a water-based aliphatic polyurethane emulsion.Waterborne polyurethanes are environmental friendly. They provide a tough, durable and highly flexible binder. The advantages associated with polyurethane coatings are their high tensile strength, excellent adhesion properties and chemical/ mechanical resistance. Properties of waterborne polyurethanes can be improved by adding modifiers, such as organoclay layers [ Kim, 2003; Xiao, 2010] .Addagrip 1000 System resin is a two-component polyurethane resin designed by Addagrip Surface Treatments UK Ltd. It can be used for sealing to protect asphalt surfaces from erosion caused by frostdamage, chemical at tack and aviation fuel spillage. Areas treated over the last twenty years at military and civil air fields have prevented further deterioration and increased the service life of the concrete pavement by an estimated 10~ 15 years. Table 2 show s the properties of the samples before and after surface treatment with Addagrip 1000 System resin. 10 cm x 10 cmx10 cm blocks w ere used. The sample surfaces w ere heated and dried by a hot compressedair system before the resin w as sprayed onto the surface [Addagrip Ltd. ] . After surface reatment with this kind of polyurethane resin, the water and fuel resistance can be improved significantly.4. 3. 2 Waterborne epoxy resinsEpoxy is a copolymer. It is formed from two different chemicals, the resin and the hardener. Most common epoxy resins are produced from a reaction between Epichlorhydrin and bispheno-l A, see Fig.5[Weiss,1997] .Waterborne epoxy resin, with excellent adhesion properties, is another possible alternative. Waterborne epoxy resin is a stable resin material prepared by dispersing epoxy resin in the form of particles or droplet s into the dispersion medium based on water as a continuous phase.Application ofwaterborne epoxy resinsis not onlyconvenient but alsocauses no pollution tothe environmentand no harm to thehuman body. Afteradding a properamount of curing/ solidifying agent, advantages like high strength ,high-temperature resistance, chemical resistance, fatigue resistance, and high antiaging ability can be achieved [ Xiao, 2010; Weiss, 1997]5 ConclusionCTS are widely used for pavement surface treatments because of their excellent adhesion properties and good fuel resistance. How ever, because of their high PAHs content s, which are considered as human carcinogens, CTS are not allowed anymore in some of the developed counties. In order to eliminate the significant threat of pollution to our environment, w e should stop using CTS. Instead, modified bitumen emulsions, epoxy modified bitumen, waterborne polyurethanes and waterborne epoxy resins could achievecomparable or better properties than CTS. All of them have good adhesion, excellent chemical and ageing resistance. Epoxy modified bitumen has extremely high temperature stability and strength. Application of waterborne resins is convenient and the curing rate can be easily adjusted by changing the ratio of chemical components. And, the most important, these alternatives are environmental friendly.AcknowledgementsThe scholarship from the China Scholarship Council is acknowledged. T he authors would like to express thanks to ICOPAL BV for their materials and technical supports.References[1] AddagripLtd.www .adda grip [2] Ammala A, Hill A J.Poly( M-Xylene Adipamide)-Kaolinite and Poly( M-XyleneAdipamide)-Montmorillonite Nanocomposites [J] . Journal of Applied Polymer Science, 2007(104):1377- 1381.[3] Austin. http: / /www .ci. austin. tx . us/ watershed/ coaltar- ban. htm. Austin Bans Use of Coal Tar Sealants-first in Nation,2005.[4] CCTIR.China Coal Tar Industry Report 2006-2010.[R],2008.[5] Elliott R. 2008. Epoxy Asphalt: Concept and Properties. Workshop of TRB 2008.[6] IARC. Polynuclear Aromatic 4 Bitumens , Coal Tars and Der ived Products,Shale Oils and Soots. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Humans,Vol. 35. Lyon, France:International Agency for Research on Cancer,1985.[7] Kennedy J. Alter native Materials and Techniques for Road Pavement Construction[R] . London: DOE Energy Efficiency Office,1997.[8] Kim B K, Seo J W, Jeong H M. Morphology and Properties of Waterborne Polyurethane/ clay Nanocomposite [J]. European[9] SCHER. Scientific Committee on Health and Environmental Risks. Coal tar pitch, high temperature Human Health Part. CAS No: 65996- 93- 2. EINECS No: 266- 028-2.[10] Thom N H. Asphalt Cracking: A Nottingham Perspective [J].Engenaria Civil/ Civil Engineering, 2006(26) : 75- 84.[11] TRB-EC102. Asphalt Emulsion Technology. Transportation Research Board[S], 2006.[12] Van Leest A J, Gaar keuken G. The F O D. Resistance of Sur face Layers on Airfields in the Netherlands; in Situ and Laboratory Testing [R] . 2005 European Airport Pavement Workshop, 2005. [13] Van Metre P C, Mahler B J. Trends in Hydrophobic Organic Contaminants in Urban and Reference Lake Sediments Across the United States, 1970- 2001[J]. Environmental Science and Technology,2005, 39( 15) : 5567- 5574.[14] Weiss K D. Paint and Coatings: A Mature Industry in Transition [J].Progress in Polymer Science, 1997, 22(2):203- 245.[15] Xiao Y. Literature Review on Possible Alternatives to Tar for Antiskid Layers . Delft University o f Technology, Road and Railway Engineering Section[R] . Report No.7-10-185-1,the Nether lands.。

城市垃圾卫生填埋场毕业设计(全套毕业设计含外文翻译及图纸)

城市垃圾卫生填埋场摘要本工程设计的主要内容包括：城市生活垃圾卫生填埋场处理总平面布置（选址和场区总体设计等等），填埋工艺，防治工程，渗滤液收集导排工程，渗滤液处理工程，地下水、地表水导排处理工程，填埋气体收集与利用设计，环境监测设计，封场工程，辅助工程（如绿化、道路等），设备选型，二次污染防治设计，经济分析等等。

关键词垃圾卫生填埋设计渗滤液气体The Design Of Sanitary LandfillAbstractThis engineering design primary coverage includes: The city life trash health fill in bury the field to process the total plane arrangement (selected location and field area system design and so on), fills in buries the craft, the preventing and controlling project, the infiltration fluid collection leads a row of project, the infiltration fluid processing project, the ground water, the surface water leads the row of processing project, fills in buries the gathering of gas and the use design, the environmental monitoring design, seals the field project, auxiliary project (for example afforestation, path and so on), equipment shaping, two pollution preventing and controlling design, economic analysis and so on.Keywords Rubbish Landfill of hygiene Design Ooze and filtrate Gas目录摘要 (I)Abstract (II)第1章概论 (5)1.1设计背景 (5)1.1.1 生活垃圾的危害 (5)1.1.2生活垃圾的处理方法及国内外处理现状 (5)1.1.3卫生填埋法的类型及发展趋势 (7)1.2城市概况及自然条件 (8)1.2.1 城市概况 (8)1.2.2 自然条件 (9)1.3该城市垃圾的处理概况 (10)1.3.1 垃圾成分 (11)1.3.2 垃圾处理状况及存在问题 (11)1.4设计的必要性及依据 (15)1.4.1 设计的必要性 (15)1.4.2 设计的依据 (15)1.5设计的主要内容 (16)1.6本章小结 (16)第2章总体设计 (17)2.1填埋方案的确定 (17)2.2 设计规模 (18)2.2.1 服务人口 (18)2.2.2 垃圾产量 (18)2.3 场址选择 (19)2.3.1 填埋场址的选择原则 (19)2.3.2 垃圾填埋场场址的确定 (20)2.4 本章小结 (20)第3章垃圾收运系统 (21)3.1 垃圾的收运原则 (21)3.2 垃圾收运规模 (21)3.3 垃圾收运现状及设计收运方案的确定 (22)3.4 本章小结 (23)第4章垃圾处理场工程设计 (24)4.1 垃圾处理场的组成 (24)4.2 卫生填埋场工程设计 (24)4.2.1 垃圾场总库容及使用年限的确定 (24)4.2.2 垃圾坝 (24)4.2.3 渗滤液的收集系统 (26)4.2.4 渗滤液处理设备尺寸的计算 (37)4.2.5 填埋气导排 (48)4.2.6 终期封场 (49)4.3 配套工程 (50)4.3.1 道路工程 (50)4.3.2 围墙与绿化工程 (50)4.3.3 给水工程 (51)4.3.4 消防工程 (51)4.3.5 防洪工程 (51)4.3.6 防震工程 (51)4.3.7 通讯工程 (51)4.3.8 电气工程 (52)4.3.9 垃圾场主要机械设备 (52)4.4 本章小结 (52)第5章环境保护与环境监测 (53)5.1 环境保护 (53)5.1.1 污染来源 (53)5.1.2 环境保护标准和规定 (54)5.1.3 环境保护措施 (54)5.2 环境监测 (55)5.3 本章小结 (56)总结 (57)致谢 (60)参考文献 (61)英文翻译 (62)中文译文： (68)第1章概论1.1设计背景1.1.1生活垃圾的危害随着经济的发展，人们生活消费水平的提高，城市的生活垃圾产生量日渐增加。

液压专业毕业设计外文翻译(有译文、外文文献)值得收藏哦!

外文原文：The Analysis of Cavitation Problems in the Axial Piston Pumpshu WangEaton Corporation,14615 Lone Oak Road,Eden Prairie, MN 55344This paper discusses and analyzes the control volume of a piston bore constrained by the valve plate in axial piston pumps. The vacuum within the piston bore caused by the rise volume needs to be compensated by the flow; otherwise, the low pressure may cause the cavitations and aerations. In the research, the valve plate geometry can be optimized by some analytical limitations to prevent the piston pressure below the vapor pressure. The limitations provide the design guide of the timings and overlap areas between valve plate ports and barrel kidneys to consider the cavitations and aerations. _DOI: 10.1115/1.4002058_Keywords: cavitation , optimization, valve plate, pressure undershoots1 IntroductionIn hydrostatic machines, cavitations mean that cavities or bubbles form in the hydraulic liquid at the low pressure and collapse at the high pressure region, which causes noise, vibration, and less efficiency.Cavitations are undesirable in the pump since the shock waves formed by collapsed may be strong enough to damage components. The hydraulic fluid will vaporize when its pressure becomes too low or when the temperature is too high. In practice, a number of approaches are mostly used to deal with the problems: (1) raise the liquid level in the tank, (2) pressurize the tank, (3) booster the inlet pressure of the pump, (4) lower the pumping fluid temperature, and (5) design deliberately the pump itself.Many research efforts have been made on cavitation phenomena in hydraulic machine designs. The cavitation is classified into two types in piston pumps: trapping phenomenon related one (which can be preventedby the proper design of the valve plate) and the one observed on the layers after the contraction or enlargement of flow passages (caused by rotating group designs) in Ref. (1). The relationship between the cavitation and the measured cylinder pressure is addressed in this study. Edge and Darling (2) reported an experimental study of the cylinder pressure within an axial piston pump. The inclusion of fluid momentum effects and cavitations within the cylinder bore are predicted at both high speed and high load conditions. Another study in Ref. (3) provides an overview of hydraulic fluid impacting on the inlet condition and cavitation potential. It indicates that physical properties (such as vapor pressure, viscosity, density, and bulk modulus) are vital to properly evaluate the effects on lubrication and cavitation. A homogeneous cavitation model based on the thermodynamic properties of the liquid and steam is used to understand the basic physical phenomena of mass flow reduction and wave motion influences in the hydraulic tools and injection systems (4). Dular et al. (5, 6) developed an expert system for monitoring and control of cavitations in hydraulic machines and investigated the possibility of cavitation erosion by using the computational fluid dynamics (CFD) tools. The erosion effects of cavitations have been measured and validated by a simple single hydrofoil configuration in a cavitation tunnel. It is assumed that the severe erosion is often due to the repeated collapse of the traveling vortex generated by a leading edge cavity in Ref. (7). Then, the cavitation erosion intensity may be scaled by a simple set of flow parameters: the upstream velocity, the Strouhal number, the cavity length, and the pressure. A new cavitation erosion device, called vortex cavitation generator, is introduced to comparatively study various erosion situations (8).More previous research has been concentrated on the valve plate designs, piston, and pump pressure dynamics that can be associated with cavitations in axial piston pumps. The control volume approach and instantaneous flows (leakage) are profoundly studied in Ref. [9]. Berta et al. [10] used the finite volume concept to develop a mathematical model in which the effects of port plate relief grooves have been modeled andthe gaseous cavitation is considered in a simplified manner. An improved model is proposed in Ref. [11] and validated by experimental results. The model may analyze the cylinder pressure and flow ripples influenced by port plate and relief groove design. Manring compared principal advantages of various valve plate slots (i.e., the slots with constant, linearly varying, and quadratic varying areas) in axial piston pumps [12]. Four different numerical models are focused on the characteristics of hydraulic fluid, and cavitations are taken into account in different ways to assist the reduction in flow oscillations [13].The experiences of piston pump developments show that the optimization of the cavitations/aerations shall include the following issues: occurring cavitation and air release, pump acoustics caused by the induced noises, maximal amplitudes of pressure fluctuations, rotational torque progression, etc. However, the aim of this study is to modify the valve plate design to prevent cavitation erosions caused by collapsing steam or air bubbles on the walls of axial pump components. In contrastto literature studies, the research focuses on the development of analytical relationship between the valve plate geometrics and cavitations. The optimization method is applied to analyze the pressure undershoots compared with the saturated vapor pressure within the piston bore.The appropriate design of instantaneous flow areas between the valveplate and barrel kidney can be decided consequently.2 The Axial Piston Pump and Valve PlateThe typical schematic of the design of the axis piston pump is shown in Fig. 1. The shaft offset e is designed in this case to generate stroking containment moments for reducing cost purposes.The variation between the pivot center of the slipper and swash rotating center is shown as a. The swash angle αis the variable that determines the amount of fluid pumped per shaft revolution. In Fig. 1, the n th piston-slipper assembly is located at the angle ofθ. The displacement of the n thnpiston-slipper assembly along the x-axis can be written asx n= R tan（α）sin（θ）+ a sec（α）+ e tan(α) (1)nwhere R is the pitch radius of the rotating group.Then, the instantaneous velocity of the n th piston isx˙n = R 2sec ()αsin （n θ）α+ R tan （α）cos （n θ）ω+ R 2sec ()αsin （α）α + e 2sec ()αα (2)where the shaft rotating speed of the pump is ω=d n θ / dt .The valve plate is the most significant device to constraint flow inpiston pumps. The geometry of intake/discharge ports on the valve plateand its instantaneous relative positions with respect to barrel kidneys areusually referred to the valve plate timing. The ports of the valve plateoverlap with each barrel kidneys to construct a flow area or passage,which confines the fluid dynamics of the pump. In Fig. 2, the timingangles of the discharge and intake ports on the valve plate are listed as(,)T i d δ and (,)B i d δ. The opening angle of the barrel kidney is referred to asϕ. In some designs, there exists a simultaneous overlap between thebarrel kidney and intake/discharge slots at the locations of the top deadcenter (TDC) or bottom dead center (BDC) on the valve plate on whichthe overlap area appears together referred to as “cross -porting” in thepump design engineering. The cross-porting communicates the dischargeand intake ports, which may usually lower the volumetric efficiency. Thetrapped-volume design is compared with the design of the cross-porting,and it can achieve better efficiency 14]. However, the cross-porting isFig. 1 The typical axis piston pumpcommonly used to benefit the noise issue and pump stability in practice.3 The Control Volume of a Piston BoreIn the piston pump, the fluid within one piston is embraced by the piston bore, cylinder barrel, slipper, valve plate, and swash plate shown in Fig. 3. There exist some types of slip flow by virtue of relativeFig. 2 Timing of the valve platemotions and clearances between thos e components. Within the control volume of each piston bore, the instantaneous mass is calculated asM= n V(3)nwhere ρ and n V are the instantaneous density and volumesuch that themass time rate of change can be given asFig. 3 The control volume of the piston boren n n dM dV d V dt dt dtρρ=+ (4) where d n V is the varying of the volume.Based on the conservation equation, the mass rate in the control volume isn n dM q dtρ= (5)where n q is the instantaneous flow rate in and out of one piston. From the definition of the bulk modulus,n dP d dt dtρρβ= (6) where Pn is the instantaneous pressure within the piston bore. Substituting Eqs. (5) and (6) into Eq. (4) yields(?)n n n n n ndP q dV d V w d βθθ=- (7) where the shaft speed of the pump is n d dtθω=. The instantaneous volume of one piston bore can be calculated by using Eq. (1) asn V = 0V + P A [R tan （α）sin （n θ）+ a sec （α） + e tan(α) ] (8)where P A is the piston sectional area and 0V is the volume of eachpiston, which has zero displacement along the x-axis (when n θ=0, π).The volume rate of change can be calculated at the certain swash angle, i.e., α =0, such thattan cos n p n ndV A R d αθθ=（）（） (9) in which it is noted that the piston bore volume increases or decreaseswith respect to the rotating angle of n θ.Substituting Eqs. (8) and (9) into Eq. (7) yields0[tan()cos()] [tan sin sec tan() ]n P n n n p n q A R dP d V A R a e βαθωθαθαα-=-++（）（）（）(10)4 Optimal DesignsTo find the extrema of pressure overshoots and undershoots in the control volume of piston bores, the optimization method can be used in Eq. (10). In a nonlinear function, reaching global maxima and minima is usually the goal of optimization. If the function is continuous on a closed interval, global maxima and minima exist. Furthermore, the global maximum (or minimum) either must be a local maximum (or minimum) in the interior of the domain or must lie on the boundary of the domain. So, the method of finding a global maximum (or minimum) is to detect all the local maxima (or minima) in the interior, evaluate the maxima (or minima) points on the boundary, and select the biggest (or smallest) one. Local maximum or local minimum can be searched by using the first derivative test that the potential extrema of a function f( · ), with derivative ()f ', can solve the equation at the critical points of ()f '=0 [15].The pressure of control volumes in the piston bore may be found as either a minimum or maximum value as dP/ dt=0. Thus, letting the left side of Eq. (10) be equal to zero yieldstan()cos()0n p n q A R ωαθ-= (11)In a piston bore, the quantity of n q offsets the volume varying and thendecreases the overshoots and undershoots of the piston pressure. In this study, the most interesting are undershoots of the pressure, which may fall below the vapor pressure or gas desorption pressure to cause cavitations. The term oftan()cos()p n A R ωαθ in Eq. (11) has the positive value in the range of intake ports (22ππθ-≤≤), shown in Fig. 2, which means that the piston volume arises. Therefore, the piston needs the sufficient flow in; otherwise, the pressure may drop.In the piston, the flow of n q may get through in a few scenariosshown in Fig. 3: (I) the clearance between the valve plate and cylinder barrel, (II) the clearance between the cylinder bore and piston, (III) the clearance between the piston and slipper, (IV) the clearance between the slipper and swash plate, and (V) the overlapping area between the barrel kidney and valve plate ports. As pumps operate stably, the flows in the as laminar flows, which can be calculated as [16]312IV k k Ln i I k h q p L ωμ==∑ (12)where k h is the height of the clearance, k L is the passage length,scenarios I –IV mostly have low Reynolds numbers and can be regarded k ω is the width of the clearance (note that in the scenario II, k ω =2π· r, in which r is the piston radius), and p is the pressure drop defined in the intake ports as p =c p -n p (13)where c p is the case pressure of the pump. The fluid films through theabove clearances were extensively investigated in previous research. The effects of the main related dimensions of pump and the operating conditions on the film are numerically clarified inRefs. [17,18]. The dynamic behavior of slipper pads and the clearance between the slipper and swash plate can be referred to Refs. [19,20]. Manring et al. [21,22] investigated the flow rate and load carrying capacity of the slipper bearing in theoretical and experimental methods under different deformation conditions. A simulation tool calledCASPAR is used to estimate the nonisothermal gap flow between the cylinder barrel and the valve plate by Huang and Ivantysynova [23]. The simulation program also considers the surface deformations to predict gap heights, frictions, etc., between the piston and barrel andbetween the swash plate and slipper. All these clearance geometrics in Eq.(12) are nonlinear and operation based, which is a complicated issue. In this study, the experimental measurements of the gap flows are preferred. If it is not possible, the worst cases of the geometrics or tolerances with empirical adjustments may be used to consider the cavitation issue, i.e., minimum gap flows.For scenario V, the flow is mostly in high velocity and can be described by using the turbulent orifice equation as((Tn d i d d q c A c A θθ= (14)where Pi and Pd are the intake and discharge pressure of the pump and ()i A θ and ()d A θ are the instantaneous overlap area between barrel kidneys and inlet/discharge ports of the valve plate individually.The areas are nonlinear functions of the rotating angle, which is defined by the geometrics of the barrel kidney, valve plate ports,silencing grooves, decompression holes, and so forth. Combining Eqs.(11) –(14), the area can be obtained as3()K IV A θ==(15)where ()A θ is the total overlap area of ()A θ=()()i d A A θλθ+, and λ is defined as=In the piston bore, the pressure varies from low tohigh while passing over the intake and discharge ports of the valve plates. It is possible that the instantaneous pressure achieves extremely low values during the intake area( 22ππθ-≤≤ shown in Fig. 2) that may be located below the vapor pressure vp p , i.e., n vp p p ≤;then cavitations canhappen. To prevent the phenomena, the total overlap area of ()A θ mightbe designed to be satisfied with30()K IV A θ=≥(16)where 0()A θ is the minimum area of 0()A θ=0()()i d A A θλθ+ and 0λis a constant that is0λ=gaseous form. The vapor pressure of any substance increases nonlinearly with temperature according to the Clausius –Clapeyron relation. With the incremental increase in temperature, the vapor pressure becomes sufficient to overcome particle attraction and make the liquid form bubbles inside the substance. For pure components, the vapor pressure can be determined by the temperature using the Antoine equation as /()10A B C T --, where T is the temperature, and A, B, and C are constants[24].As a piston traverse the intake port, the pressure varies dependent on the cosine function in Eq. (10). It is noted that there are some typical positions of the piston with respect to the intake port, the beginning and ending of overlap, i.e., TDC and BDC (/2,/2θππ=- ) and the zero displacement position (θ =0). The two situations will be discussed as follows:(1) When /2,/2θππ=-, it is not always necessary to maintain the overlap area of 0()A θ because slip flows may provide filling up for the vacuum. From Eq. (16), letting 0()A θ=0,the timing angles at the TDC and BDC may be designed as31cos ()tan()122IV c vpk k i I P k p p h A r L ωϕδωαμ--≤+∑ (17) in which the open angle of the barrel kidney is . There is nocross-porting flow with the timing in the intake port.(2) When θ =0, the function of cos θ has the maximum value, which can provide another limitation of the overlap area to prevent the low pressure undershoots suchthat 30(0)K IVA =≥ (18)where 0(0)A is the minimum overlap area of 0(0)(0)i A A =.To prevent the low piston pressure building bubbles, the vaporpressure is considered as the lower limitation for the pressure settings in Eq. (16). The overall of overlap areas then can be derived to have adesign limitation. The limitation is determined by the leakage conditions, vapor pressure, rotating speed, etc. It indicates that the higher the pumping speed, the more severe cavitation may happen, and then the designs need more overlap area to let flow in the piston bore. On the other side, the low vapor pressure of the hydraulic fluid is preferred to reduce the opportunities to reach the cavitation conditions. As a result, only the vapor pressure of the pure fluid is considered in Eqs. (16)–(18). In fact, air release starts in the higher pressure than the pure cavitation process mainly in turbulent shear layers, which occur in scenario V.Therefore, the vapor pressure might be adjusted to design the overlap area by Eq. (16) if there exists substantial trapped and dissolved air in the fluid.The laminar leakages through the clearances aforementioned are a tradeoff in the design. It is demonstrated that the more leakage from the pump case to piston may relieve cavitation problems.However, the more leakage may degrade the pump efficiency in the discharge ports. In some design cases, the maximum timing angles can be determined by Eq. (17)to not have both simultaneous overlapping and highly low pressure at the TDC and BDC.While the piston rotates to have the zero displacement, the minimum overlap area can be determined by Eq. 18 , which may assist the piston not to have the large pressure undershoots during flow intake.6 ConclusionsThe valve plate design is a critical issue in addressing the cavitation or aeration phenomena in the piston pump. This study uses the control volume method to analyze the flow, pressure, and leakages within one piston bore related to the valve plate timings. If the overlap area developed by barrel kidneys and valve plate ports is not properly designed, no sufficient flow replenishes the rise volume by the rotating movement. Therefore, the piston pressure may drop below the saturated vapor pressure of the liquid and air ingress to form the vapor bubbles. To control the damaging cavitations, the optimization approach is used to detect the lowest pressure constricted by valve plate timings. The analytical limitation of the overlap area needs to be satisfied to remain the pressure to not have large undershoots so that the system can be largely enhanced on cavitation/aeration issues.In this study, the dynamics of the piston control volume is developed by using several assumptions such as constant discharge coefficients and laminar leakages. The discharge coefficient is practically nonlinear based on the geometrics, flow number, etc. Leakage clearances of the control volume may not keep the constant height and width as well in practice due to vibrations and dynamical ripples. All these issues are complicated and very empirical and need further consideration in the future. Theresults presented in this paper can be more accurate in estimating the cavitations with these extensive studies.Nomenclature0(),()A A θθ= the total overlap area between valve plate ports and barrel kidneys 2()mmAp = piston section area 2()mmA, B, C= constantsA= offset between the piston-slipper joint and surface of the swash plate 2()mmd C = orifice discharge coefficiente= offset between the swash plate pivot and the shaft centerline of the pump 2()mmk h = the height of the clearance 2()mmk L = the passage length of the clearance 2()mmM= mass of the fluid within a single piston (kg)N= number of pistonsn = piston and slipper counter,p p = fluid pressure and pressure drop (bar)Pc= the case pressure of the pump (bar)Pd= pump discharge pressure (bar)Pi = pump intake pressure (bar)Pn = fluid pressure within the nth piston bore (bar)Pvp = the vapor pressure of the hydraulic fluid(bar)qn, qLn, qTn = the instantaneous flow rate of each piston(l/min)R = piston pitch radius 2()mmr = piston radius (mm)t =time (s)V = volume 3()mmwk = the width of the clearance (mm)x ,x ˙= piston displacement and velocity along the shaft axis (m, m/s) x y z --=Cartesian coordinates with an origin on the shaft centerline x y z '''--= Cartesian coordinates with an origin on swash plate pivot ,αα=swash plate angle and velocity (rad, rad/s)β= fluid bulk modulus (bar)δδ= timing angle of valve plates at the BDC and TDC (rad),B Tϕ= the open angle of the barrel kidney(rad)ρ= fluid density(kg/m3),θω= angular position and velocity of the rotating kit (rad, rad/s)μ=absolute viscosity(Cp),λλ= coefficients related to the pressure drop外文中文翻译：在轴向柱塞泵气蚀问题的分析本论文讨论和分析了一个柱塞孔与配流盘限制在轴向柱塞泵的控制量设计。

毕业设计英文翻译(原文)

编号：毕业设计(论文)外文翻译（原文）院（系）：桂林电子科技大学专业：电子信息工程学生姓名： xx学号： xxxxxxxxxxxxx 指导教师单位：桂林电子科技大学姓名： xxxx职称： xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。

毕业设计的英文翻译----开放式控制器体系结构 - 过去,现在和未来

Open Controller Architecture - Past, Present and FutureGunter Pritschow (Co-ordinator), Yusuf Altintas, Francesco Jovane, Yoram Koren, Mamoru Mitsuishi, Shozo Takata, Hendrik van Brussel, Manfred Weck, Kazuo YamazakiAbstractOpen Control Systems are the key enabler for the realization of modular and re-configurable manufacturing systems. The large number of special purpose machines and the high level of automation have led to an increasing importance of open control systems based on vendor neutral standards. This paper gives an overview on the past, present and future of Open Controller Architecture. After reflecting on the different criteria, categories and characteristics of open controllers in general, the CNC products in the market are evaluated and an overview on the world-wide research activities in Europe, North America and Japan is given. Subsequently the efforts to harmonize the different results are described in order to establish a common world-wide standard in the future. Due to the “mix-and-match’’ nature of open controllers concentrated attention must be paid to testing mechanisms in the form of conformance and interoperability tests.Keywords: Open architecture control, CNC, Machine tool1 INTRODUCTIONOpen Architecture Control (OAC) is a well known term in the field of machine control. Since the early nineties several initiatives world-wide have worked on concepts for enabling control vendors, machine tool builders and end-users to benefit more from flexible and agile production facilities. The main aim was the easy implementation and integration of customer-specific controls by means of open interfaces and configuration methods in a vendor-neutral, standardized environment [13][19].The availability and broad acceptance of such systems result in reduced costs and increased flexibility. Software can be reused and user-specific algorithms or applications can be integrated. Users can design their controls according to a given configuration. This trend was forced both by the increasing number of special purpose machines with a high level of automation and the increasing development costs for software (Figure 1).Figure 1: CNC Hardware and software -Actual trend existingIn the past the CNC market was dominated by heterogeneous, device-oriented systems with proprietary hardware and software components. The tight coupling of application software, system software and hardware led to very complex and inflexible systems. Great efforts were made to maintain and further develop the products according to new market requirements. Modern CNC approaches, which comprise extensive functionality to achieve a high quality and flexibility of machining results combined with a reduced processing time, favor PC- based solutions with a homogenous, standardized environment (Figure 2). The structure is software- oriented and configurable due to defined interfaces and software platforms. Open control interfaces are necessary for continuously integrating new advanced functionality into control systems and are important for creating re-configurable manufacturing units [17]. Unbundling hardware and software allows profiting from the short innovation cycles of the semiconductor industry and information technology. With the possibility for reusing software components, the performance of the overall system increases simply by upgrading the hardware platform.Figure 2: PC-based, software-oriented Control SystemsThere are a lot of benefits for suppliers and users of open control systems (Figure 3) [7]. CNC designers and academics benefit from a high degree of openness coveringalso the internal interfaces of the CNC. For CNC users the external openness is much more important. It provides the methods and utilities for integrating user-specific applications into existing controls and for adapting to user-specific requirements, e.g. adaptable user interfaces or collection of machine and production data. The external openness is mainly based on the internal openness but has functional or performance Iimitations .2 STATE OF THE ART2.1 Control Systems and their interfacesControls are highly sophisticated systems due to very strict requirements regarding real-time and reliability. For controlling the complexity of these systems hardware and software interfaces are an essential means. The interfaces of control systems can be divided into two groups-external and internal interfaces (Figure4).External InterfacesThese interfaces connect the control system to superior units, to subordinate units and to the user. They can be divided into programming interfaces and communication interfaces. NC and PLC programming interfaces are harmonized by national or international standards, such as RS-274, DIN 66025 or IEC 61131-3. Communication interfaces are also strongly influenced by standards. Fieldbus systems like SERCOS, Profibus or DeviceNet are used as the interface to drives and 110s. LAN (Local Area Network) networks mainly based on Ethernet and TCP/lP do reflect the interfaces to superior systems.Internal InterfacesInternal interfaces are used for interaction and data- exchange between components that build up the control- system core. An important criterion in this area is the support of real-time mechanisms. To achieve a re-configurable and adaptable control the internal architecture of the control system is based on a platform concept. The main aims are to hide the hardware-specific details from the software components and to establish a defined but flexible way of communication between the software components. An application programming interface(API) ensures these requirements. The whole functionality of a control system is subdivided into several encapsulated, modular software components interacting via the defined API.2.2 Hardware and software structure of control systemsFigure 5 shows different variants for the hardware structures of control systems. Variant a) shows an analog drives interface with position controller in the control system core. Each module of this structure uses its own processor which leads to a large variety of vendor-specific hardware. Combining modules leads to a significant reduction of the number of processors. Variant b) shows intelligent digital drives with integrated control functionality, which result from higher capacity, miniaturization and higher performance of the processors. Variant c) shows a PC-based single processor solution with a real-time extension of the operating system. All control-functions run as software tasks in the PC-based real-time environment.2.3 Market overviewThe controls available in the market provide different levels of openness according to the criteria shown in Figure 6. An important criterion is the use of a standardized computing platform (i.e. hardware, operating system and middleware) as an environment to execute the HMI and CNC software. Besides this, the connectivity of the CNC to upper and lower factory levels must be guaranteed. Application Programming Interfaces (API) are used to integrate third party software in the CNC products. Al though most of today’s controls offer openness concerning the operator-related control functions (Human-Machine Interface, HMI) only few controls allow users to modify their low-level control algorithms to influence the machine-related control functions.Figure 7 gives an overview of the characteristics of today’s control s ystems regarding the degree of openness.Although many control systems provide open interfaces for software integration (e.g. OPC) there is still no common definition of data which is passed back and forth via the programming interface. Therefore, the control systems available on the market today do not implicitly support “plug-and-play” features. To improve this situation, the fieldbus systems can serve as a role model (see Figure 8). The variety of different fieldbus systems has led to the broad consensus that harmonizing the application-oriented interfaces is desirable in order to hide the plurality and the complexity of the systems from the user. Most fieldbus organizations are already using so-called device profiles in order to support the interchangeability of the devices of different vendors.For example, the SERCOS interface standard (IEC61491) for the cyclic and deterministic communication between CNC and drives has defined the semantics forapprox. 400 parameters describing drive and control functions which are used by the devices of different vendors.3 DEFINITIONS AND CATEGORIES OF OPENNESS3.1 DefinitionsThe “Technical Committee of Open Systems” of IEEE defines an open system as follows: “An open system provides capabilities that enable properly implemented applications to run on a variety of platforms from multiple vendors, interoperate with other system applications and present a consistent style of interaction with the user” (IEEE 1003.0).To estimate the openness of a controller the following criteria can be applied (Figure 9):Portability. Application modules (AM) can be used on different platforms without any changes, while maintaining their capabilities.Extendibility. A varying number of AM can run on a platform without any conflicts.Inferoperability. AM work together in a consistent manner and can interchange data in a defined way.Scalability. Depending on the requirements of the user, functionality of the AM and performance and size of the hardware can be adapted.To fulfill the requirements of the IEEE-definition and these criteria of openness, an open control system must be:vendor neutral. This guarantees independence of single proprietary interests.consensus-driven. It is controlled by a group of vendors and users (usually in the form of a user group or an interested group).standards-based. This ensures a wide distribution in the form of standards (national/international standards or de-facto standards).freely available. It is free of charge to any interested party.3.2 Categories of Open Control SystemsIf we speak of openness in control systems, the following categories can be identified (Figure 10):Open HMl: The openness is restricted to the non-real-time part of the control system. Adaptations can be made in user oriented applications.Kernel with restricted openness: The control kernel has a fixed topology, but offers interfaces to insert user-specific filters even for real-time functions.Open Control System: The topology of the control kernel depends on the process. It offers interchangeability, scalability, portability and interoperability.Open control systems that are available today mostly offer the possibility for modifications in the non-real-time part in a fixed software topology. They lack the necessary flexibility and are not based on vendor-neutral standards.3.3 RequirementsA vendor-neutral open control system can only be realized if the control functionality is subdivided in functional units and if well-defined interfaces between these units are specified (Figure 11). Therefore modularity can be identified as the key for an open system architecture. In determining the module complexity there is an obvious trade-off between the degree of openness and the cost of integration [6]. Smaller modules provide a higher level of openness and more options, but increase the complexity and integration costs. Furthermore such a low level of granularity can lead to much higher demands for resources and it may even deteriorate the real-time performance of the overall system.Combining modules in the manner of “mix-and-match’’ requires a comprehensive set of standard Application Programming Interfaces (APIs). For vendor-neutral open control systems the interfaces need to be standardized and broadly accepted. Due to the complexity of such modular systems the definition of a system architecture is recommendable and helpful. This leads to the introduction of so-called system platforms (Figure 12). These platforms encapsulate the specifics of a computing system by absorbing the characteristics of hardware, operating system and communication. The availability of such middleware systems facilitates the easy porting of application software and also the interoperability of application modules even in distributed heterogeneous environments.Due to the possibility to “mix-and-match’’ modules via standardized interfaces the quality of the overall system is determined by the degree of the interoperability between the single modules (see Section 5).4 SYSTEMS ON THE WAY TO THE MARKET4.1 Major international activitiesOSEC (Japan)The OSE (Open System Environment for Manufacturing) consortium was established in December 1994. Three project phases were carried out until March 1999 [1][2][3]. The OSEC Architecture was intended to provide end users, machine makers, control vendors, software vendors, system integrators, etc. a standard platform for industrial machine controllers, with which they can add their own unique values to the industrial machines, and hence promote the technical and commercial development of the industrial machines. The OSEC API is defined in the form of an interface protocol, which is used to exchange messages among controller software components representing the functionality and the real- time cycle. Each functional block can be encapsulated as an object so it is not necessary to deal with how a functional block processes messages to it at architecture level (Figure 13). Although the structure of functional blocks can be defined uniquely by the OSEC architecture from a logical point of view, the system is neither determined nor limited at its implementation phase because there are so many options for implementations. These options may include system contrivances such as device driver, interprocess communication, installation mechanisms such as static library and DLL, hardware factors like selection of controller card, and implementations of software modules added for execution control and/or monitoring of various software. In other words, the implementation model to realize the architecture model is not limited to a particular model. In this way, it is assured to incorporate various ideas in the implementation model depending on the system size or its hardware implementation and/or utilization.JOP (Japan)In parallel to the OSE consortium activities, MSTC formed the Open-Controller Technical Committee (OC- TC) from 1996 to 2000, under the umbrella of JOP (Japanese Open Promotion Group). The objectives of OC-TC were to provide the opportunities for various companies to discuss and work together on the standardization of open controller technologies. The OC- TC was also expected to act as liaison between domestic and international activities in this field. OC-TC was participated by approximately 50 members, which included major Japanese controller vendors, machine tool builders, integrators, users, and academics. Some of the members represented the other groups concerning open controllers such as the OSE consortium and the FA Intranet Promotion Group .One of the working groups was engaged in developing a standard API for interfacing between NC and PC-based HMI. It should be also effective for the communication between NC and an upper level management controller. The work was carried out based on the proposals from the major controller vendors and that from the OSE consortium. The developed specifications were named PAPI and released July, 1999 [4] [5]. PAPI was approved as a JIS (Japan Industrial Standard) technical report and published in October, 2000. To demonstrate the effectiveness of the specifications developed by OC-TC, in Nagoya in October 1999, two CNCs manufactured by different vendors were connected to a Windows NT machine in which the same HMI systems developed by the University of Tokyo were implemented (Figure 14). Since any specific controller architecture is not assumed, PAPI can be implemented in various types of existing CNC systems, such as PC + proprietary NC, PC + NC board, and Software NC on PC+110 board. The HMI system communicates with the CNCs via PAPI which is a function-oriented software library in the programming language C. The PAPI interface is neutralizing the vendor-specific interface by mapping the PAPI calls to the vendor-specific API and protocol.OMAC (USA)The Open Modular Architecture Controllers (OMAC) Users Group is an industry forum to advance the state of controller technology [l0]. An effort was undertaken within OMAC to define API specification for eventual submittal to an established standards body. The OMAC API adopted a component-based approach to achieve plug-and-play modularization, using interface classes to specify the API [11]. For distributed communication, component-based technology uses proxy agents to handle method invocations that cross process boundaries. OMAC API contains diffe rent “sizes” and “types” of reusab le plug-and-play components - component, module, and task - each with a unique Finite State Machine (FSM) model so that component collaboration is performed in a known manner. The term component applies to reusable pieces of software that serves as a building block within an application while the term module refers to a container of components. Tasks are components used to encapsulate programmable functional behavior consisting of a series of steps that run to completion, including support for starting, stopping, restarting, halting, and resuming, and may be run multiple times while a controller is running. Tasks can be used to build controller programs consisting of a series of Transient Tasks, with ability to restart and navigate, or as standalone Resident Tasks to handle specialized controller requirements, (e.g., axis homing or ESTOP).To integrate components, a framework is necessary to formalize the collaborations and other life cycle aspects in which components operate. The OMAC API uses Microsoft Component Object Model (COM) as the initial framework in which to develop components, with the expected benefit that control vendors could then concentrate on application-specific improvements that define their strategic market-share - as opposed to spending valuable programming resources reinventing and maintaining software “plumbing.”The primary problem with COM framework, specifically under the Windows 2000 operating system, is the lack of hard, real-time preemptive scheduling, but third party extensions to Windows 2000 can be used to overcome this requirement.Figure 15 illustrates a sketch of OMAC API controller functionality. The HMI module is responsible for human interaction with a controller including presenting data, handing commands, and monitoring events and in the OMAC API “mirrors” the actual controller with references to all the major modules and components via proxy agents. The Task Coordinator module is responsible for sequencing operations and coordinating the various modules in the system based on programmable Tasks. The Task Coordinator can be considered the highest level Finite State Machine in the controller. A Task Generator module translates an application-specific control program (e.g., RS 274 part program) into a series of application-neutral Transient Tasks. The Axis Group module is responsible for coordinating the motions of individual axes, transforming an incoming motion segment specification into a sequence of equi-time- spaced setpoints for the coordinated axes. The Axis module is responsible for servo control of axis motion, transforming incoming motion setpoints into setpoints for the corresponding actuators 10 points. The Control Law component is responsible for servo control loop calculations to reach specified setpoints. OSACA (Europe)In Europe the ESPRIT project OSACA (Open System Architecture for Controls within Automation Systems) was initiated in 1992 with the aim to unite European interests and to create a vendor-neutral standard for open control systems[9][16].It was supported by major European control vendor and machine tool builders. OSACA reached a mature state already in April 1996 having at its disposal a stable set of specifications and a tested pool for system software. Based on these results, several application-oriented projects were carried out. In 1988 two pilot demonstrators in the automotive industry proved the interoperability of OSACA-compliant controllers and applications. The OSACA association eth currently 35 members from all over the word is the lasting organization to keep and maintain the OSACA-related specifications.The basic technical approach of the OSACA architecture is the hierarchical decomposition of control functionality into so-called functional units (Figure 16).For each of these functional units (e.g. motion control, motion control manager, axescontrol, logic control, etc.) the interfaces are specified by applying object-oriented information models. This technique is similar to the approach of MAP/MMS but with a limited and manageable number of object classes.The data interface consists of several variable objects that support the read and/or write access to data structure(data flow).The data can be of a simple type or of a complex type(array, structure, union).By using formal templates(Figure17) all the characteristics of a single interface object are specified. These elements cover the name (e.g, “mc-active-feed-override”), the type (e.g. UNS32: 32-bit unsigned value), the scaling (e.g. 0.l%),the range and the access rights (read only, to all the major modules and components via proxy write only, read/write) of the data. An additional description is to avoid misinterpretations of the use of the data. The process interface consists of several process objects that are used to describe the dynamic behavior (control flow) of the application modules by means of finite state machine (FSM). The state machines are described by static states, dynamic states and transitions to change the states of a given state-machine. The transitions can handle input and output parameters to pass data between application modules via the communication platform. The formal template for such process interfaces consists of an unambiguous description and the following attributes: list of static states (identifier, list of possible transitions), list of dynamic states (identifier) and a list of transitions (input parameters, output parameters, return codes). The process interface can also be used to activate application-specific functions in form of procedure calls. The interoperability of distributed application modules is supported by an infrastructure (so-called OSACA platform) which comprises client-server principles, synchronous and asynchronous calls and event handling via any underlying communication protocol and media (e.g. by using the TCP/lP protocol). A dedicated configuration runtime system is handling the system’s startup and shutdown. Besides, it also allows an easy reconfiguration of the system.开放式控制器体系结构- 过去，现在和未来摘要开放式控制系统是用于模块化和可重新配置制造系统实现的关键推动者。

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8.1 模态测试
关于目标的模态试验,第一个模式组合的频率范围低频率(5赫兹)到350赫兹在有和没有绝缘材料的条件下，已被研究。

将要测定的模态特征为以下:
• 本征频率,
• 模态形状,和
• 模态阻尼因素。

测试物体(带附件和密封装置)被放置在一个刚性支承,在两个不同的位置进行刺激(见图14)。

这些对构型的测量与由有限元分析出来的预期结果是相关的，在没有内部绝
缘,200赫兹的条件下。

阻尼略低于模型里的任意值(0.4 -1%代替了1%)。

再有绝缘材料的情况下,装备好的壳体的表现就有显著的改变:,整体位移模式阻尼增加到2.2%和皮肤模式增加到5%。

这样的高阻尼通常被认为是有益的,因为它应该降低峰值水平在飞行动态载荷的条件下。

频率也有所改变由于绝缘材料的缘故,第一模态频率
从95赫兹到91赫兹的转换。

在这两种情况下,第一个模式在所有位移模式是平面与对峙,而第一个平面外模式发生在有绝缘的条件下的115赫兹和没有隔缘的条件下的122赫兹。

如图15所示。

8.2 振动测试
振动试验的目的是验证瓦元素到飞行载荷水平。

因此,系统的完整性必须得到验证在一个代表动态载荷的应用下。

图15.相应的频率一分之三模式(全瓦与绝缘)
预测分析已经完成,开槽已进在一定的频率下实现了,以限制高峰负荷到可接受的值。

这是合理的,因为事实上动态负载的包裹很苛刻(最大负载从阿丽亚娜5环境),和由于面板必须经受住动态测试才可以在以后的热力负荷条件下进行测试。

两种类型的振动诱因已经被评估出来: •正弦振动,荷载规范见表1
表1
正弦振动荷载规范
频率范围（赫兹）加速度峰值扫描率5-16 10mm 1/3
16-60 10g
60-70 22.5g 2
70-200 22.5g
图14 模型测试设备
• 随机振动与载荷被描述在图16中。

振动测试设备，和一个完全装备的瓦一起显示在图17中。

装备的整体性能令人非常满意:CMC 面板经受住了负载而且没有显著损伤。

密封材料被移出了外壳(见图18),这并不代表实际的使用结果。

在现实情况下,他们确实会被压紧在相邻板的密封条材料上。

加速计和应变计结果正在进行分析，总体结果符合预期。

一些与预测在高频率下的
差异(500 - 2000赫兹)将进行进一步的研究(如图19)。

声学测试最近被执行了，其结果也在正表2
音阶带声级（分贝）
31 154 63 153 125 152 1250
150 500 150 1000 150 2000 149 全程音压位准
160
这种频谱被逐步应用,一次就指定负载为总声压级的145.9 分贝,一次为154.8 分贝和最后一个是158.9分贝。

测试装置见图20。

整体的结果又令人满意的,在测试期间没有任何损坏的迹象。

测量的压力也是在图16 随机振动载荷
图17 震动测试
图18 震动测试后的面板图20 声学测试频率（赫兹）
图19 测量加速度范例
CMC材料许用值。

好结果为接下来的热力、
热机械的测试提供了方便。

9. 热测试
这些测试都是基于热加载通用瓦,和测
试活动有以下目的:
•验证C / SiC瓦TPS概念脱离侧瓦组件的整
体保温功能,
•验证两个相邻瓦片接口之间的热绝缘功
能，
•验证热绝缘功能的附件系统是表象的环境,
•验证通过热机械应力影响在只有热负载的
条件下
•通过测量全球热映射反馈到有限元热计算
模型精度
•验证通过的热负荷与机械负荷相结合对热
机械应力的影响。

测试中包含在C / SiC面板连接到是表
象的冷结构,借助其绝缘系统9个附件和密
封。

另外,为了验证两个相邻瓦组件之间的接
口,·另一个C / SiC面板已经添加(其绝缘,
密封和附件系统)一侧的瓦片,先前在动态环
境中测试（如图21）。

•接口孔为M3的连接，用测试手段,
•排气洞保持与外部的试验台同样水平的压
力，
•DT孔访问，以及
•压力传感器的固定和通道。

装配好的的测试物体显示在图22中。

进行热测试在一个循序渐进的过程中
进行。

第一次进行了预测试和一个持续时间
为500秒的期间,一个事件热通量350 千瓦/
平方米应用,对应280 千瓦/平方米收到的瓦
片,如下图23。

图21 热学测试
图23 热测试中指定热剖面
图22 组装好的测试件
这提前测试允许验证可行性,特定热负荷的应用(尤其是冷却阶段),并确认通过一个通量计代替热电偶控制测试的可能性，从而提供更好的控制精度。

在检测前,确定温度增加的金属附件组件是比预期要慢的,这允许进行更长期的持续测试。

因此预测试后接一个全程时间热测试的80持续期间最大。

这个测试的初步结果证实测量冷结构温度仍然低于100◦C。

然后热力测试在瓦片总成上进行,一个压差在热加载的同时被应用到表面上。

应用的热负荷,是同样的指定热试验(图23)与热使用在1000秒,而加载的压力显示在图24。

完整的测试物体被放在一个真空室来模拟环境急剧变化。

为了能够在施加热负荷的同时在面板表面上施加一个压差,一个特定的测试装置已经被德国工业设备公司设计和制造,负责这些性能的测试。

图25为这
通过热机械应力进行了第一次测试,但是在530秒后,由于通量计在测试失效而失败了。

这个失败导致瓦片的外部表面过热，达到1600 C,而公称值为1300 C。

由于这个原因中止测试,压力不能在这次测试中的得到加载。

第二次测试进行时,热条件所控制的一个高温计代替磁通计。

这次测试是完全成功的，且没有进一步的麻烦,与应用的热通量为1000秒,而相应的100 mbar压力负荷的应用之间的第700秒和第2200秒。

测试物体呈现在图26。

初步分析结果证实了已经进行过的热测试的观测。

此外,位移测量表明,该值要略高于预测在热试验,但略低于预测在热力测
试中的结果。

它也指出,在压力加载的过程中,有一个高水平的强制对流,由于压差是由连
图24 热机械测试的压力轮廓图26 测试物体准备好进行热机械测试
图25 热机械测试设备
续注入冷中性的气体的实际情况。

这种对流,不会出现在实际飞行条件下,诱导更高的通过瓦厚度的热传播率，和一旦入射热流是停止，更高的冷却速率。

这种强制对流将被考虑在测试后进行详细分析。

10。

结论
通用瓦项目,资助项目研究开始于2003年,已经证明它有能力设计和制造大型碳/ 碳化硅TPS组件，在使用最新的材料和技术条件下。

下一步,包括在最终设计的验证,机械测试和动态验证这个面板,以及热测试和热物性测试的进行，现在已经实现了。

这块板已经成功地经受住了严峻的压差载荷(130 mbar),以及苛刻的正弦和随机振动载荷。

这也是在声学室测试到负载没有明显损坏CMC面板或支座绝缘子。

密封材料部分受损,但在他们被放在的面板密封条周围时，他们的测试构型非常完整。

热性能测试和热物性测试,对瓦总成在高温条件下,包括与压力加载结合时的特性表现提供了有价值的数据。

这个测试的结果运动强有力的验证了验证TPS技术。

更多的实验探究仍要在以后执行,如进一步加强的密封材料,绝缘附件支座绝缘子和垫圈,和特定的当地碳/ 碳化硅面板区域,以及分析和测试的增压/ 减压方面。

作为已经进行了的测试活动,和将来更多的实验探究的结果,大瓦概念将达到必要的使用技术成熟水平，以达到发展全面重返汽车的示范作用。