毕业设计冷凝器外文翻译

第一篇：毕业设计冷凝器外文翻译

吉林化工学院本科毕业设计（论文）外文翻译

氨制冷系统的节能设计，改造和蒸发式冷凝器的控制

阿卜杜勒穆罕默德和凯利，工业评估中心，代顿大学

摘要

氨制冷系统通常提供了许多节能商机，因为他们的大动力消耗，运行时间长的和动态的操作。氨制冷系统的能源使用高度依赖于冷凝头的压力，而这是一个函数的蒸发式冷凝器容量和控制功能。本文研究系统能源利用中聚光能力和冷凝器的控制之间的关系。它首先开发方法来确定冷凝器的性能，然后以仿真模型模拟压缩机和冷凝器风扇的年度能源利用。，它使用工程基本面和经验两个数据，准确地捕捉压缩机，冷凝器和环境湿球温度之间的协同效应。节约能源是三种情况：安装在冷凝器风机变频驱动器，采用湿球控制方法战略和提高聚光性能。以说明气候的影响，这些模拟是两个不同的ASHRAE气候区，迈阿密，佛罗里达州和执行明尼阿波利斯，明尼苏达州，这是炎热和寒冷的气候分别。结果表明，提高表现不佳的冷凝器的性能是最经济有效的节能测量。但是节约能源从冷凝器安装变频驱动器球迷和利用湿球的方法策略取决于环境气候条件，与位置无关。接下来，内部收益率的计算方法来安装额外的聚光能力超越在为相同的两个ASHRAE气候区新建筑应用的标准做法。结果表明，安装两次基线聚光能力，内部收益率超过20 ％。综上所述，本文提出的设计，改造的综合方法在氨制冷系统蒸发式冷凝器的控制权。节约能源衍生通过使用这种方法可以显著提高氨的能量效率制冷系统。

介绍

约7.5 ％的总生产能耗用于食品加工行业，其中约21％的能量是电能(二零零六年环评)。在这些设备中，氨制冷系统是最大的能源消耗部分。制冷与冷却工艺所用电量是食品加工行业(二零零六年EIA)的用电量的27％。制冷系统使用的能量是高度依赖于冷凝压力，而这又是冷凝器容量和控制性能。因此，提高聚光能力和控制可导致显著的节能效果。

本文首先确定使用的数据从实际的聚光性能制冷控制系统。然后是开发仿真模型来计算每年的能源使用所研究的压缩机和冷凝器风扇。该仿真模型，用来计算节能三

吉林化工学院本科毕业设计（论文）外文翻译

个节能措施(ECMS)：在冷凝器风扇安装变频器，采用湿球的方法策略，提高聚光性能。以说明气候的影响，这些仿真用于执行迈阿密，佛罗里达州和明尼苏达州明尼阿波利斯，这是炎热和寒冷的气候分别。文章最后决定回报的安装额外的容量超出标准规范的内部收益率在新的建筑应用。

系统说明

分析系统是一个两阶段的氨制冷系统具有两个低压侧压缩机和两个高级压缩机。所有的压缩机是螺杆式与滑阀控制和热虹吸油冷却。一种蒸发式冷凝器以恒定的速度从系统散发热量。对于本文的其余部分，术语系统将参考冷凝器风扇和压缩机。从冷凝器泵的能源使用小，并且不评价了本文。关键系统参数，包括电动机电流，氨的压力和温度从制冷控制系统获得。氨性数据的计算使用参考流体热力学和输运性质数据(NIST，2010)也被称为REFPROP。图中显示了制冷系统的替补的示意图。

图1。电路图制冷系统的pH值图上

计算排热到冷凝器

冷凝压力是决定系统能源利用的一个关键变量。为了准确地计算冷凝压力，冷凝器性能必须确定。在第一步骤中确定冷凝器性能是计算从压缩机排出到总热量冷凝器。在系统中的能量平衡显示了总的热拒绝了冷凝器是由低和高级压缩机加两个设置在制冷（QREF0）低和高级压缩机两者的压缩或轴功率（WS）的热量。

QCond.actual = Σ QrefLS +Σ QrefHS +Σ WSLS +Σ WsHS（1）

吉林化工学院本科毕业设计（论文）外文翻译

所有的热拒绝从低温压缩机减去热虹吸拒绝的低级压缩机油冷却（TSOC，LS）将被转移到高压侧制度。因此，由高温压缩机提供（TRprovided，HS）的制冷是：

ΣTRprovided，HS = Σ QrefLS +Σ QrefHS +Σ WLS

吉林化工学院本科毕业设计（论文）外文翻译

量可以使用等式4和来自控制系统的百分之制冷容量，计算如下：

QREF = Qrrated • ％容量

（5）

压缩热由高温级压缩机（WsHS）生产

来自控制系统的数据而获得的每个压缩机的电机电流。至相关电机电流轴功率（WS），电机电流和输入之间的关系权力必须得到发展。这种关系中，可以从点测量开发电机电流和输入功率在整个压缩机的工作范围。通过使用的压缩机（ὴm）的两个铭牌效率和f（A），轴功率或等价每个压缩机的压缩热量可以计算为：

WsHS = F（A）* ὴm

（6）

热虹吸油冷却（TSOC）

考虑了两阶段的低温循环在图1中表示的氨制冷系统。在状态1LS，氨进入压缩机作为饱和蒸汽和离开压缩机的过热蒸汽在状态2LS。路径1LSmref.LS •（h2a.LSh4.LS）（8）

通常，制造商报告的体积流量的空气速率，标称容量，并且热抑制因子（HRF）。体积流量是用于使用计算的质量流率空气的密度在标准条件。该HRF，这既是外部空气湿球温度计的功能温度（TWB）和饱和冷凝温度（Tcond），用于确定在额定容量冷凝器对于一个给定TWB和Tcond为（Manske，Reindl和2001年克莱因）：

额定电容容量=标称容量/ HRF（TWB，Tcond）（10）

等式9b和10可以适用于制造商的规格为蒸发冷凝器，以确定对于一个给定的湿球Tcond和效力之间的关系范围。有效性被发现是线性相关的Tcond为： effM = E0

吉林化工学院本科毕业设计（论文）外文翻译

由于蒸发式冷凝器的运行期间的实际容量已计算的，实际效果可以适合于在等式11的形式的线。测量效力与从所研究的系统Tcond数据被绘制时，无论是蒸发式冷凝器，风机和水泵是在图3满负荷生产。额定制造商从式（11）效果也绘制在同一张图来比较的有效性上一个新的蒸发式冷凝器，以其中一个已经服役了几年。图3表示该蒸发式冷凝器性能已劣化随着时间的推移。实际容量比制造商的额定容量少约40％。此信息可以被用作用于模拟程序的校准参数。例如，在图3中，冷凝器容量为一个新的冷凝器将约为1.69倍，目前的实际能力。

图3。实际和制造商有效性的蒸发式冷凝器

模拟年能源消耗

每年的能量使用的制冷系统的是压缩机和冷凝器的总和风机能耗。冷凝压力是必须正确地计算一个关键的变量正确模拟压缩机和冷凝器风扇的能源使用。以下步骤概述一方法计算压缩机功率，冷凝压力和冷凝器风扇电源。

计算压缩机输入功率

一个给定的压缩机在一定范围抽吸的额定轴功率（bhprated）和冷凝温度可以从制造商处获得。此数据可以被嵌入到一个二阶多项式方程的交互项来确定额定满载

吉林化工学院本科毕业设计（论文）外文翻译

轴功率在给定的吸气和冷凝温度（Manske 2000），如：

bhprated = P0 + P1 • Tcond + P2 • TSUC + P11 • Tcond ² + P22 • TSUC ² + P12 • Tcond • TSUC（12）

在该制冷系统中的压缩机，像许多制冷系统中，在操作碱/修剪方式，表示过去压缩机接通的每个阶段是修剪压缩机。式（4），它类似于公式12中，示出的满负荷容量压缩机吸入的函数和冷凝温度下，该压缩机运行。知道制冷负荷（参考负载）和碱的量被操作（Σ TRBase），则该部分的容量修剪压缩机的压缩机定阶段（FCTrim）可以计算如下：

FCTrim =（参考负载6789

吉林化工学院本科毕业设计（论文）外文翻译

红色=压缩机的能耗，蓝=冷凝器风扇能源，绿色=节能，广场=投资回报率，VFD =常数变速冷凝器风扇，所需时间约=利用湿球的方法和策略PERFOR =提高聚光性能。

在新建筑应用安装额外的电容容量

冷凝器是因为结构支撑，管道和控制成本来安装。因此，这是很少的成本效益来安装额外的冷凝器为唯一目的能量效率。然而，在新建筑中安装额外的冷凝器容量可以成本效益。近似的安装成本与变频驱动和湿球的做法冷凝器控制是指在公式23。增量成本（元）= 17 ·增容（MBH）+ 12,000（23）

在添加额外的冷凝器时收益率（IRR）内部收益率图9显示容量时，冷凝器的寿命是20年，能源涨价率是3 ％。内部收益率计算用于安装的50 ％的额外容量，100％，150 ％和200 ％，比7000 MBH基线能力。在这两个位置，内部收益率超过20％加倍聚光能力。因此，增加聚光能力似乎是一个非常有吸引力的选项的新建筑。

图9。返回的安装额外的电容容量内部收益率

红色=增量成本，绿色=每年节约能源成本，回报广场=内部收益率

小结与讨论

本文开发了一种方法，利用数据来校准聚光性能制冷控制系统。此校准冷凝器性能的仿真中使用模型计算所研究的年度能源使用的系统。该仿真模型是然后用来计算节能三的ECM ：在冷凝器风扇安装变频器，采用湿球的方法策略，提高聚光性能的两个不同的ASHRAE气候区。

重要的结果是：

1．制冷系统的总功耗是强烈依赖于冷凝器大小，性能和控制。

2．对于现有系统，提高了蒸发式冷凝器性能可能是最成本效益的节能措施。目视检

吉林化工学院本科毕业设计（论文）外文翻译

[4] Manske，K.A.，Reindl酒店，D.T.和克莱因2001年S.A.公司。在工业“蒸发式冷凝器的控制制冷系统制冷24 “国际杂志： 676-691。

[5]米切尔，J.W.博朗，J.E.，1998。“设计，分析和空间调节设备的控制和

系统”。威斯康星大学麦迪逊分校。

[6] 标准与技术，2010年全国学院，参考流体热力学和运输属性数（REFPROP）8.0版 [7] 国家可再生能源实验室，2005年，“用户手册TMY3s ”，http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3/ [8] Stoecker，威尔伯特，1998年，工业制冷手册。麦格劳13-

第二篇：毕业设计外文翻译

外文原文

Overview of JSp Technology

Benefits of JSp

JSp pages are translated into servlets.So, fundamentally, any task JSp pages can perform could also be accomplished by servlets.However, this underlying equivalence does not mean that servlets and JSp pages are equally appropriate in all scenarios.The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other.After all, anything you can do on a particular computer platform in the Java programming language you could also do in assembly language.But it still matters which you choose.JSp provides the following benefits over servlets alone:

•It is easier to write and maintain the HTML.Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.•You can use standard Web-site development tools.Even HTML tools that know nothing about JSp can be used because they simply ignore the JSp tags.•You can divide up your development team.The Java programmers can work on the dynamic code.The Web developers can concentrate on the presentation layer.On large projects, this division is very important.Depending on the size of your team and the complexity of your project, you can enforce a weaker or stronger separation between the static HTML and the dynamic content.Now, this discussion is not to say that you should stop using servlets and use only JSp instead.By no means.Almost all projects will use both.For some requests in your project, you will use servlets.For others, you will use JSp.For still others, you will combine them with the MVC architecture.You want the appropriate tool for the job, and servlets, by themselves, do not complete your toolkit.Advantages of JSp Over Competing Technologies

A number of years ago, Marty was invited to attend a small 20-person industry roundtable discussion on software technology.Sitting in the seat next to Marty was James Gosling, inventor of the Java programming language.Sitting several seats away was a high-level manager from a very large software company in Redmond, Washington.During the discussion, the moderator brought up the subject of Jini, which at that time was a new Java technology.The moderator asked the manager what he thought of it, and the manager responded that it was too early to tell, but that it seemed to be an excellent idea.He went on to say that they would keep an eye on it, and if it seemed to be catching on, they would follow his company's usual “embrace and extend” strategy.At this point, Gosling lightheartedly interjected “You mean disgrace and distend.”

Now, the grievance that Gosling was airing was that he felt that this company would take technology from other companies and suborn it for their own purposes.But guess what? The shoe is on the other foot here.The Java community did not invent the idea of designing pages as a mixture of static HTML and dynamic code marked with special tags.For example, ColdFusion did it years earlier.Even ASp(a product from the very software company of the aforementioned manager)popularized this approach before JSp came along and decided to jump on the bandwagon.In fact, JSp not only adopted the general idea, it even used many of the same special tags as ASp did.So, the question becomes: why use JSp instead of one of these other technologies? Our first response is that we are not arguing that everyone should.Several of those other technologies are quite good and are reasonable options in some situations.In other situations, however, JSp is clearly better.Here are a few of the reasons.Versus.NET and Active Server pages(ASp)

.NET is well-designed technology from Microsoft.ASp.NET is the part that directly competes with servlets and JSp.The advantages of JSp are twofold.First, JSp is portable to multiple operating systems and Web servers;you aren't locked into deploying on Windows and IIS.Although the core.NET platform runs on a few non-Windows platforms, the ASp part does not.You cannot expect to deploy serious ASp.NET applications on multiple servers and operating systems.For some applications, this difference does not matter.For others, it matters greatly.Second, for some applications the choice of the underlying language matters greatly.For example, although.NET's C# language is very well designed and is similar to Java, fewer programmers are familiar with either the core C# syntax or the many auxiliary libraries.In addition, many developers still use the original version of ASp.With this version, JSp has a clear advantage for the dynamic code.With JSp, the dynamic part is written in Java, not VBScript or another ASp-specific language, so JSp is more powerful and better suited to complex applications that require reusable components.You could make the same argument when comparing JSp to the previous version of ColdFusion;with JSp you can use Java for the “real code” and are not tied to a particular server product.However, the current release of ColdFusion is within the context of a J2EE server, allowing developers to easily mix ColdFusion and servlet/JSp code.Versus pHp

pHp(a recursive acronym for “pHp: Hypertext preprocessor”)is a free, open-source, HTML-embedded scripting language that is somewhat similar to both ASp and JSp.One advantage of JSp is that the dynamic part is written in Java, which already has an extensive ApI for networking, database access, distributed objects, and the like, whereas pHp requires learning an entirely new, less widely used language.A second advantage is that JSp is much more widely supported by tool and server vendors than is pHp.Versus pure Servlets

JSp doesn't provide any capabilities that couldn't, in principle, be accomplished with servlets.In fact, JSp documents are automatically translated into servlets behind the scenes.But it is more convenient to write(and to modify!)regular HTML than to use a zillion println statements to generate the HTML.plus, by separating the presentation from the content, you can put different people on different tasks: your Web page design experts can build the HTML by using familiar tools and either leave places for your servlet programmers to insert the dynamic content or invoke the dynamic content indirectly by means of XML tags.Does this mean that you can just learn JSp and forget about servlets? Absolutely not!JSp developers need to know servlets for four reasons:

1.JSp pages get translated into servlets.You can't understand how JSp works without understanding servlets.2.JSp consists of static HTML, special-purpose JSp tags, and Java code.What kind of Java code? Servlet code!You can't write that code if you don't understand servlet programming.3.Some tasks are better accomplished by servlets than by JSp.JSp is good at generating pages that consist of large sections of fairly well structured HTML or other character data.Servlets are better for generating binary data, building pages with highly variable structure, and performing tasks(such as redirection)that involve little or no output.4.Some tasks are better accomplished by a combination of servlets and JSp than by either servlets or JSp alone.Versus JavaScript

JavaScript, which is completely distinct from the Java programming language, is normally used to dynamically generate HTML on the client, building parts of the Web page as the browser loads the document.This is a useful capability and does not normally overlap with the capabilities of JSp(which runs only on the server).JSp pages still include SCRIpT tags for JavaScript, just as normal HTML pages do.In fact, JSp can even be used to dynamically generate the JavaScript that will be sent to the client.So, JavaScript is not a competing technology;it is a complementary one.It is also possible to use JavaScript on the server, most notably on Sun ONE(formerly iplanet), IIS, and BroadVision servers.However, Java is more powerful, flexible, reliable, and portable.Versus WebMacro or Velocity

JSp is by no means perfect.Many people have pointed out features that could be improved.This is a good thing, and one of the advantages of JSp is that the specification is controlled by a community that draws from many different companies.So, the technology can incorporate improvements in successive releases.However, some groups have developed alternative Java-based technologies to try to address these deficiencies.This, in our judgment, is a mistake.Using a third-party tool like Apache Struts that augments JSp and servlet technology is a good idea when that tool adds sufficient benefit to compensate for the additional complexity.But using a nonstandard tool that tries to replace JSp is a bad idea.When choosing a technology, you need to weigh many factors: standardization, portability, integration, industry support, and technical features.The arguments for JSp alternatives have focused almost exclusively on the technical features part.But portability, standardization, and integration are also very important.For example, the servlet and JSp specifications define a standard directory structure for Web applications and provide standard files(.war files)for deploying Web applications.All JSp-compatible servers must support these standards.Filters can be set up to apply to any number of servlets or JSp pages, but not to nonstandard resources.The same goes for Web application security settings.Besides, the tremendous industry support for JSp and servlet technology results in improvements that mitigate many of the criticisms of JSp.For example, the JSp Standard Tag Library and the JSp 2.0 expression language address two of the most well-founded criticisms: the lack of good iteration constructs and the difficulty of accessing dynamic results without using either explicit Java code or verbose jsp:useBean elements.10.4 Misconceptions About JSp

Forgetting JSp Is Server-Side Technology

Here are some typical questions Marty has received(most of them repeatedly).•Our server is running JDK 1.4.So, how do I put a Swing component in a JSp page?

•How do I put an image into a JSp page? I do not know the proper Java I/O commands to read image files.•Since Tomcat does not support JavaScript, how do I make images that are highlighted when the user moves the mouse over them?

•Our clients use older browsers that do not understand JSp.What should we do?

•When our clients use “View Source” in a browser, how can I prevent them from seeing the JSp tags?

All of these questions are based upon the assumption that browsers know something about the server-side process.But they do not.Thus:

•For putting applets with Swing components into Web pages, what matters is the browser's Java version—the server's version is irrelevant.If the browser supports the Java 2 platform, you use the normal AppLET(or Java plug-in)tag and would do so even if you were using non-Java technology on the server.•You do not need Java I/O to read image files;you just put the image in the directory for Web resources(i.e., two levels up from WEB-INF/classes)and output a normal IMG tag.•You create images that change under the mouse by using client-side JavaScript, referenced with the SCRIpT tag;this does not change just because the server is using JSp.•Browsers do not “support” JSp at all—they merely see the output of the JSp page.So, make sure your JSp outputs HTML compatible with the browser, just as you would do with static HTML pages.•And, of course you need not do anything to prevent clients from seeing JSp tags;those tags are processed on the server and are not part of the output that is sent to the client.Confusing Translation Time with Request Time

A JSp page is converted into a servlet.The servlet is compiled, loaded into the server's memory, initialized, and executed.But which step happens when? To answer that question, remember two points:

•The JSp page is translated into a servlet and compiled only the first time it is accessed after having been modified.•Loading into memory, initialization, and execution follow the normal rules for servlets.Table 1 gives some common scenarios and tells whether or not each step occurs in that scenario.The most frequently misunderstood entries are highlighted.When referring to the table, note that servlets resulting from JSp pages use the _jspService method(called for both GET and pOST requests), not doGet or dopost.Also, for initialization, they use the jspInit method, not the init method.Table 1.JSp Operations in Various Scenarios

JSp page translated into servletServlet compiledServlet loaded into server's memoryjspInit called_jspService called

page first written

Request 1YesYesYesYesYes

Request 2NoNoNoNoYes

Server restarted

Request 3NoNoYesYesYes

Request 4NoNoNoNoYes

page modified

Request 5YesYesYesYesYes

Request 6NoNoNoNoYes

中文翻译

JSp技术概述

一、JSp的好处

JSp页面最终会转换成servler。因而，从根本上，JSp页面能够执行的任何任务都可以用servler来完成。然而，这种底层的等同性并不意味着servler和JSp页面对于所有的情况都等同适用。问题不在于技术的能力，而是二者在便利性、生产率和可维护性上的不同。毕竟，在特定平台上能够用Java编程语言完成的事情，同样可以用汇编语言来完成，但是选择哪种语言依旧十分重要。

和单独使用servler相比，JSp提供下述好处：

JSp中HTML的编写与维护更为简单。JSp中可以使用常规的HTML：没有额外的反斜杠，没有额外的双引号，也没有暗含的Java语法。

能够使用标准的网站开发工具。即使对那些对JSp一无所知的HTML工具，我们也可以使用，因为它们会忽略JSp标签（JSp tags）。

可以对开发团队进行划分。Java程序员可以致力于动态代码。Web开发人员可以将经理集中在表示层（presentation layer）上。对于大型的项目，这种划分极为重要。依据开发团队的大小，及项目的复杂程度，可以对静态HTML和动态内容进行弱分离（weaker separation）和强分离（stronger separation）。

在此，这个讨论并不是让您停止使用servlets，只使用JSp。几乎所有的项目都会同时用到这两种技术。针对项目中的某些请求，您可能会在MVC构架下组合使用这两项技术。我们总是希望用适当的工具完成相对应的工作，仅仅是servlet并不能填满您的工具箱。

二、JSp相对于竞争技术的优势

许多年前，Marty受到邀请,参加一个有关软件技术的小型(20个人)研讨会.做在Marty旁边的人是James Gosling---Java编程语言的发明者。隔几个位置,是来自华盛顿一家大型软件公司的高级经理。在讨论过程中,研讨会的主席提出了Jini的议题,这在当时是一项新的Java技术.主席向该经理询问他的想法.他继续说,他们会持续关注这项技术,如果这项技术变得流行起来,他们会遵循公司的“接受并扩充(embrace and extend)”的策略.此时, Gosling随意地插话说“你的意思其实就是不接受且不扩充(disgrace and distend)。”

在此, Gosling的抱怨显示出，他感到这个公司会从其他公司那里拿走技术,用于他们自己的目的.但你猜这次怎么样?这次鞋子穿在了另一只脚上。Java社团没有发明这一思想----将页面设计成由静态HTML和用特殊标签标记的动态代码混合组成.。ColdFusion多年前就已经这样做了。甚至ASp(来自于前述经理所在公司的一项产品)都在JSp出现之前推广了这种方式。实际上,JSp不只采用了这种通用概念,它甚至使用许多和ASp相同的特殊标签。

因此,问题变成:为什么使用JSp,而不使用其他技术呢?我们的第一反应是我们不是在争论所有的人应该做什么。其他这些技术中,有一些也很不错,在某些情况下也的确是合情合理的选择.然而,在其他情形中,JSp明显要更好一些。下面给出几个理由。

与.NET和Active Server pages(ASp)相比

.NET是Microsoft精心设计的一项技术。ASp.NET是与servlets和JSp直接竞争的技术。JSp的优势体现在两个方面。

首先,JSp可以移植到多种操作系统和Web服务器,您不必仅仅局限于部署在Windows 和IIS上尽管核心.NET平台可以在好几种非Windows平台上运行，但ASp这一部分不可以。您不能期望可以将重要的ASp.NET应用部署到多种服务器和操作系统。对于某些应用，这种差异没有什么影响。但有些应用，这种差异却非常重要。

其次，对于某些应用，底层语言的选择至关重要。例如，尽管.NET的C#语言设计优良，且和Java类似，但熟悉核心C#语法和众多工具库的程序员很少。此外,许多开发者依旧使用最初版本的ASp。相对于这个版本,JSp在动态代码方面拥有明显的优势。使用JSp,动态部分是用Java编写的,而非VBScript过其他ASp专有的语言,因此JSp更为强劲,更适合于要求组件重用的复杂应用。

当将JSp与之前版本的ColdFusion对比时，您可能会得到相同的结论。应用JSp，您可以使用Java编写“真正的代码”，不必依赖于特定的服务器产品。然而，当前版本的ColdFusion满足J2EE服务器的环境，允许开发者容易的混合使用ColdFusion和Servlet/JSp代码。

与pHp相比

pHp（“pHp：Hypertext preprocessor”的递归字母缩写词）是免费的、开放源代码的、HTML嵌入其中的脚本语言，与ASp和JSp都有某种程度的类似。JSp的一项优势是动态部分用Java编写，而Java已经在联网、数据库访问、分布式对象等方面拥有广泛的ApI，而pHp需要学习全新的、应用相对广泛的语言。JSp的第二项优势是，和pHp相比，JSp拥有极为广泛的工具和服务器提供商的支持。

与纯Servlet相比

原则上，JSp并没有提供Servlet不能完成的功能。实际上，JSp文档在后台被自动转换成Servlet。但是编写（和修改）常规的HTML，要比无数println语句生成HTML要方便得多。另外，通过将表示与内容分离，可以为不同的人分配不同的任务：网页设计人员使用熟悉的工具构建HTML，要么为Servlet程序员留出空间插入动态内容，要么通过XML标签间接调用动态内容。

这是否表示您只可以学习JSp，将Servlet丢到一边呢？当然不是！由于以下4种原因，JSp开发人员需要了解Servlet：

（1）JSp页面会转换成Servlet。不了解Servlet就无法知道JSp如何工作。

（2）JSp由静态HTML、专用的JSp标签和Java代码组成。哪种类型的Java代码呢？当然是Servlet代码！如果不了解Servlet编程，那么就无法编写这种代码。

（3）一些任务用Servlet完成比用JSp来完成要好。JSp擅长生成由大量组织有序的结构化HTML或其他字符数据组成的页面。Servlet擅长生成二进制数据，构建结构多样的页面，以及执行输出很少或者没有输出的任务（比如重定向）。

（4）有些任务更适合于组合使用Servlet和JSp来完成，而非单独使用Servlet或JSp。

与JavaScript相比

JavaScript和Java编程语言完全是两码事，前者一般用于在客户端动态生成HTML，在浏览器载入文档时构建网页的部分内容。这是一项有用的功能，一般与JSp的功能（只在服务器端运行）并不发生重叠。和常规HTML页面一样，JSp页面依旧可以包括用于JavaScript的SCRIpT标签。实际上，JSp甚至能够用来动态生成发送到客户端的JavaScript。因此，JavaScript不是一项竞争技术，它是一项补充技术。

JavaScript也可以用在服务器端，最因人注意的是SUN ONE（以前的iplanet）、IIS和BroadVision服务器。然而，Java更为强大灵活、可靠且可移植。

与WebMacro和Velocity相比

JSp决非完美。许多人都曾指出过JSp中能够改进的功能。这是一件好事，JSp的优势之一是该规范由许多不同公司组成的社团控制。因此，在后续版本中，这项技术能够得到协调的改进。

但是，一些组织已经开发出了基于Java的替代技术，试图弥补这些不足。据我们的判断，这样做是错误的。使用扩充JSp和Servlet技术的第三方工具，如Apache Structs，是一种很好的思路，只要该工具带来的好处能够补偿工具带来的额外复杂性。但是，试图使用非标准的工具代替JSp则不理想。在选择一项技术时，需要权衡许多方面的因素：标准化、可移植性、集成性、行业支持和技术特性。对于JSp替代技术的争论几乎只是集中在技术特性上，而可移植性、标准化和集成性也十分重要。例如，Servlet和JSp规范为Web应用定义了一个标准的目录结构，并提供用于部署Web应用的标准文件（.war文件）。所有JSp兼容的服务器必须支持这些标准。我们可以建立过滤器作用到任意树木的Servlet和JSp页面上，但不能用于非标准资源。Web应用安全设置也同样如此。

此外，业界对JSp和Servlet技术的巨大支持使得这两项技术都有了巨大的进步，从而减轻了对JSp的许多批评。例如，JSp标准标签库和JSp 2.0表达式语言解决了两种最广泛的批评：缺乏良好的迭代结构；不使用显式的Java代码或冗长的jsp:useBean元素难以访问动态结果。

三、对JSp的误解

忘记JSp技术是服务器端技术

下面是Marty收到的一些典型问题（大部分问题不止一次的出现）。

我们的服务器正在运行JDK1.4。我如何将Swing组件用到JSp页面中呢？

我如何将图像放到JSp页面中？我不知道读取图像文件应该使用哪些Java I/O命令。

Tomcat不支持JavaScript，当用户在图像上移动鼠标时，我如何使图像突出显示呢？

我们的客户使用不理解JSp的旧浏览器。我应该怎么做？

当我们的客户在浏览器中使用“View Source”（查看源代码）时，如何阻止他们看到JSp标签？

所有这些问题都基于浏览器对服务器端的过程在有所了解的假定之上。但事实上浏览器并不了解服务器端的过程。因此：

如果要将使用Swing组件的applet放到网页中，重要的是浏览器的Java版本，和服务器的Java版本无关。如果浏览器支持Java 2平台，您可以使用正常的AppLET（或Java插件）标签，即使在服务器上使用了非Java技术也须如此。

您不需要Java I/O来读取图像文件，您只需将图像放在存储Web资源的目录中（即WEB-INF/classes向上两级的目录），并输出一个正常的IMG标签。

您应该用SCRIpT标签，使用客户端JavaScript创建在鼠标下会更改的图像，这不会由于服务器使用JSp而改变。

浏览器根本不“支持”JSp----它们看到的只是JSp页面的输出。因此，如同对待静态HTML页面一样，只需确保JSp输出的HTML与浏览器兼容。

当然，您不需要采取什么措施来阻止客户看到JSp标签，这些标签在服务器上进行处理，发送给客户的输出中并不出现。

混淆转换期间和请求期间

JSp页面需要转换成servlet。Servlet在编译后，载入到服务器的内容中，初始化并执行。但是每一步发生在什么时候呢？要回答这个问题，要记住以下两点：

JSp页面仅在修改后第一次被访问时，才会被转换成servlet并进行编译；

载入到内存中、初始化和执行遵循servlet的一般规则。

表1列出一些常见的情形，讲述在该种情况下每一步是否发生。最常被误解的项已经突出标示出来。在参考该表时，要注意，由JSp页面生成的servlet使用_jspService方法（GET和pOST请求都调用该函数），不是doGet或dopost方法。同样，对于初始化，它们使用jspInit方法，而非init方法。

表1 各种情况下的JSp操作

将JSp 页面转换成servlet编译Servlet 将Servlet 载入到服务器内存中调用jspInit 调用_jspService

页面初次创建

请求 1有有有有有

请求 2无无无无有

服务器重启后

请求3无无有有有

请求 4无无无无有

页面修改后

请求 5有有有有有

请求 6无无无无有

第三篇：毕业设计三相异步电动机外文翻译

中文翻译

异步电动机具有结构简单、运行可靠、价格低、维护方便等一系列的优点，因此，异步电动机被广泛应用在电力拖动系统中。尤其是随着电力电子技术的发展和交流调速技术的日益成熟，使得异步电动机在调速性能方面大大提高。目前，异步电动机的电力拖动已被广泛地应用在各个工业电气自动化领域中。就三相异步电动机的机械特性出发，主要简述电动机的启动，制动、调速等技术问题。三相异步电动机的机械特性文

三相异步电动机的机械特性是指电动机的转速n与电磁转矩Tem之间的关系。由于转速n与转差率S有一定的对应关系，所以机械特性也常用Tem＝f（s）的形式表示。三相异步电动机的电磁转矩表达式有三种形式，即物理表达式、参数表达式和实用表达式。物理表达式反映了异步电动机电磁转矩产生的物理本质，说明了电磁转矩是由主磁通和转子有功电流相互作用而产生的。参数表达式反映了电磁转矩与电源参数及电动机参数之间的关系，利用该式可以方便地分析参数变化对电磁转矩的影响和对各种人为特性的影响。实用表达式简单、便于记忆，是工程计算中常采用的形式。

电动机的最大转矩和启动转矩是反映电动机的过载能力和启动性能的两个重要指标，最大转矩和启动转矩越大，则电动机的过载能力越强，启动性能越好。

三相异步电动机的机械特性是一条非线性曲线，一般情况下，以最大转矩（或临界转差率）为分界点，其线性段为稳定运行区，而非线性段为不稳定运行区。固有机械特性的线性段属于硬特性，额定工作点的转速略低于同步转速。人为机械特性曲线的形状可用参数表达式分析得出，分析时关键要抓住最大转矩、临界转差率及启动转矩这三个量随参数的变化规律。三相异步电动机的启动

小容量的三相异步电动机可以采用直接启动，容量较大的笼型电动机可以采用降压启动。降压启动分为定子串接电阻或电抗降压启动、Y-D降压启动和自耦变压器降压启动。定子串电阻或电机降压启动时，启动电流随电压一次方关系减小，而启动转矩随电压的平方关系减小，它适用于轻载启动。Y-D降压启动只适用于正常运行时为三角形联结的电动机，其启动电流和启动转矩均降为直接启动时的1/3，它也适用于轻载启动。自耦变压器降压启动时，启动电流和启动转矩均降为直接启动时的l/k2（k为自耦变压器的变比），适合带较大的负载启动。

绕线转子异步电动机可采用转子串接电阻或频敏变阻器启动，其启动转矩大、启动电流小，适用于中、大型异步电动机的重载启动。

软启动器是一种集电机软启动、软停车、轻载节能和多种保护功能于一体的新型电动机控制装置，国外称为Soft Starter。它的主要构成是串接于电源与被控电动机之间的三相反并联晶闸管及其电子控制电路。运用串接于电源与被控电动机之间的软启动器，以不同的方法，控制其内部晶闸管的导通角，使电动机输入电压从零以预设函数关系逐渐上升，直至启动结束，赋予电动机全电压，即为软启动。在软启动过程中，电动机启动转矩逐渐增加，转速也逐渐增加。软启动器实际上是个调压器，用于电动机启动时，输出只改变电压并没有改变频率。

三相异步电动机的调速

三相异步电动机的调速方法有变极调速、变频调速和变转差率调速。其中变转差率调速包括绕线转子异步电动机的转子串接电阻调速、串级调速和降压调速。

变极调速是通过改变定子绕组接线方式来改变电机极数，从而实现电机转速的变化。变极调速为有级调速，变极调速时的定子绕组联结方式有三种：Y-YY、顺串Y-反串Y、D-YY。其中Y-YY联结方式属于恒转矩调速方式，另外两种属于恒功率调速方式。变极调速时，应同时对调定子两相接线，这样才能保证调速后电动机的转向不变。

变频调速是现代交流调速技术的主要方向，它可实现无级调速，适用于恒转矩和恒功率负载。

绕线转子电动机的转子串接电阻调速方法简单，易于实现，但调速是有级的，不平滑，且低速时特性软，转速稳定性差，同时转子铜损耗大，电动机的效率低。串级调速克服了转子串接电阻调速的缺点，但设备要复杂得多。

异步电动机的降压调速主要用于风机类负载的场合，或高转差率的电动机上，同时应采用速度负反馈的闭环控制系统。

把电压和频率固定不变的工频交流电变换为电压或频率可变的交流电的装置称作“变频器”。为了产生可变的电压和频率，该设备首先要把电源的交流电变换为直流电（DC），这个过程叫整流。再把直流电（DC）变换为交流电（AC），这个过程叫逆变，把直流电变换为交流电的装置叫逆变器（inverter）。对于逆变为频率可调、电压可调的逆变器我们称为变频器。变频器输出的波形是模拟正弦波，主要用在三相异步动机的调速，又叫变频调速器。附录 二

外文原文

Asynchronous motor has a simple structure, reliable operation, low price, convenient maintenance and a series of advantages, therefore, asynchronous motor is widely used in electric drive system.Especially with the development of power electronic technology and AC drive technology becomes more mature, greatly improve the speed performance makes the asynchronous motor.At present, electric drive asynchronous motor has been widely used in various industrial electrical automation.The mechanical properties of three-phase asynchronous motor starting, the main motor starting, braking, speed control technology.The mechanical properties of 1 three-phase asynchronous motor Mechanical characteristics of three-phase asynchronous motor is refers to the relationship between the speed of the motor electromagnetic torque of N and Tem.Due to the speed of N and slip S have a certain relationship, so the mechanical properties are also commonly used Tem = f(s)representation.Electromagnetic torque expression of three-phase asynchronous motor has three forms, namely physical expression, parameters and practical expression.Physical expressions reflect the physical nature of electromagnetic torque of asynchronous motor, the electromagnetic torque is generated by the main flux and rotor active current interaction.Parameter expression reflects the relationship between parameters of electromagnetic torque and power supply parameters and motor, the expression can be used to influence easily analyze the influence of parameter variation on the electromagnetic torque and all kinds of human characteristics.Practical expressions in a simple, easy to remember, is often used in engineering calculation in the form of.The maximum torque of motor and torque are two important indexes reflecting the overload capacity of the motor and starting performance, maximum torque and start torque motor overload capacity is bigger, stronger, better starting performance.The mechanical characteristic of three-phase asynchronous motor is a nonlinear curve, under normal circumstances, with the maximal torque(or critical slip)as a cutoff point, the linear segment for the stable operation region, while the nonlinear section is not stable operating region.Hard characteristic is linear segment inherent mechanical properties, the nominal operating point speed slightly lower than the synchronous speed.Shape parameters available expressions man-made mechanical characteristic curve analysis, analysis the key to grasp the maximum torque, starting torque variation of critical slip and the three with the parameters of.2 three-phase asynchronous motor starting Three-phase asynchronous motor with small capacity can be used to directly start, cage motor with large capacity can adopt step-down start.Step-down start into stator resistance or reactance step-down start, Y-D step-down start and autotransformer start.The stator resistance or motor step-down start, starting current voltage relations with a reduced, and the starting torque with the square of the voltage is reduced, it is suitable for the starting load.Only applicable to motor start to normal operation for the triangle connection Y-D buck, the starting current and starting torque is reduced to direct startup 1/3, which is also suitable for the starting load.Autotransformer start, starting current and starting torque is reduced to direct startup l/k2(k is the self coupling transformer), suitable for large load starting.The wound rotor asynchronous motor with rotor series resistance or frequency sensitive rheostat starting, the starting torque, small starting current, suitable for heavy load starting, large asynchronous motor.The soft starter is a novel control device for motor motor soft start, soft stop, light load energy saving and various protecting functions in one, called Soft Starter.The main structure is connected in series between the power supply and the controlled motor three-phase inverse parallel thyristor and its electronic control circuit.Through the series of soft starter is connected between the power supply and the controlled motor, in different ways, its internal control thyristor conduction angle, so that the motor input voltage from zero to a preset function gradually rise, until the end of the motor start, give full voltage, namely soft start.In the soft start-up process, starting torque motor speed increases gradually, gradually increasing.The soft starter is actually a regulator, for when the motor is started, the output voltage does not change the frequency change.3 speed of three-phase asynchronous motor Control method of the three-phase asynchronous motor with variable speed, variable speed and variable slip speed.The variable slip ratio control includes a rotor winding rotor asynchronous motor series resistance speed control, cascade control and blood pressure control.Variable speed is by changing the stator winding connection mode to change the pole number, so as to realize the change of motor speed.Variable speed is speed-regulation, variable stator winding connection speed of three kinds: Y-YY, Y-, D-YY and Y run.The Y-YY connection is constant torque speed control mode, another two species belong to the constant power control mode.Variable pole speed, should also be on the stator two-phase wiring, so that we can guarantee the speed regulation motor steering.Variable frequency speed control is the main direction of modern AC speed regulation technology, it can realize stepless speed regulation, suitable for constant torque and constant power load.Wound rotor rotor motor series resistance speed control method is simple, easy to implement, but speed is not smooth, level, and low speed characteristics of soft, speed stability is poor, and the rotor copper loss, motor efficiency is low.Cascade speed control to overcome the rotor series resistance speed disadvantage, but the equipment is much more complex.Step-down speed asynchronous motor for fan load, or high slip motor, closed-loop control system should be accompanied by negative feedback of speed.The industrial frequency alternating current voltage and frequency of fixed to variable voltage or frequency of the alternating current.

第四篇：交通毕业设计外文及翻译

Synchro在交通控制与设计中的应用

在城市的较小的区域内，可以对区域内的所有交叉口进行控制;在城市较大的区域，可以对区域进行分区分级控制。分区的结果往往使面控制成为一个由几条线控制组成的分级集中控制系统，这时，可认为各线控制是面控制中的一个单元；有时分区的结果是成为一个点，线，面控制的综合性分级控制系统。现在对城市道路进行区域协调控制就是将其划分为多级多个信号控制子区，对信号子区进行协调控制，优化管理控制信号子区，然后对整个道路进行区域协调控制，达到整个城市道路优化的目的。

把城市道路划分为多个信号控制子区，也就是进行城市道路干线交叉口交通信号协调控制，把城市划分为多个主路控制，再把主路上各个交叉口进行联动控制，同时，对单个交叉口信号控制优化的同时需要考虑主路上下游各个交叉口的联动控制。主路上的各个交叉口按照设计的信号配时方案进行运行，使车辆进入城市主干道交叉口时，不至经常遇到红灯，称为城市主干道交叉口信号协调控制，称为“绿波”信号控制。

城市单点交叉口作为城市交通网络中的重要组成部分，作为城市道路交通问题的关键点。对城市单点交叉口，评价标准的参考指标：交叉口的通行能力、进口道的饱和度、道路交叉口进口道停车延误、交叉口进口道停车次数、进口道排队长度和汽车的油耗等。交叉口定时信号控制配时方法在不断的改进之中，国内外大部分学者认为从不同的评价指标出发，可以采用不同的种优化算法寻求其它更合理的配时方法。

平面交叉口按交通管制方式可以分为全无控制交叉口、主路优先控制交叉口、信号灯控制交叉口、环形交叉口等几种类型。主路优先控制交叉口，是在次路上设停车让行或减速让行标志，指令次路车辆必须停车或减速让主路车辆优先通行的一种交通管制方式。

交叉口是道路网中通行能力的“瓶颈”和交通事故的“黑点”。国内外城市中的交通堵塞主要发上在交叉口，造成车辆中断，事故增多，延误严重。如日本大城市中的机动车在城市中心的旅行时间约三分之一花在平面交叉口上。同时，交叉口也是交通事故的主要发生源。美国交通事故约有一半发生在交叉口；原联邦德国道路上的交通事故约有百分之三十六发上在交叉口，城市中的交通事故约有百分之六十到百分之八十发生在交叉口及其附近。因此，交叉口这个交通事故“多发源”问题不能不引起人们的高度关注。怎样对城市交叉口实施科学管理就是本

节要讨论的问题。实施管制的方式取决于交叉口的几何特征和交通状况目的是为了保障交叉口的交通安全和和充分发挥交叉口的通行能力。本节主要以十字交叉口为主，讨论全无控制交叉口和主路优先控制交叉口，同时简要介绍现代环形交叉口的基本要点。

单个交叉口的控制策略会对其上游及下游道路交叉口的车流量产生很大的影响，上游和下游交叉口距离越近交通流量越大的情况下，影响会越大。交通信号“点控制”就是把单独的交叉口拿出来进行单独的分析，对其进行单独的信号优化和道路控制策略，而不考虑该交叉口对其上下游交叉口的影响。城市道路交通信号区域协调控制的就是研究在一个城市道路子区内，对各个道路交叉口进行的信号周期时长、交叉口的绿信比以及路口间的相位差进行优化，以减小交叉口的停车延误、提高城市路网的通行能力的交通区域信号协调控制方法。随着城市道路区域信号协调控制理论的发展，研究者发现，可以把一个较大的城市的道路交通区域路网看成一个大的整体，对其进行交通信号协调控制及优化，由于道路路网及机动车流量的复杂性，但是对其优化结果对其通行能力的提高不是很理想。因此，从20世纪70年代，许多研究者开始尝试将庞大、复杂繁琐的道路路网按照一定的原则和方法模型进行划分，划分成若干个信号控制子区，然后再对信号控制子区域内进行协调信号控制，用以提高城市里整个道路路网的协调控制效果。

目前，城市道路交通拥堵问题己经成为全国乃至全世界都普遍关注问题。城市道路及交叉口作为城市交通道路的基本服务设施，主要包括道路交叉口与路段，其服务性能的良好运行直接影响到城市交通的正常运转。

城市道路交叉口是道路系统的重要组成部分，城市道路通过交叉口这个节点把各条道路互相连接构成城市的道路路网，来协调交叉口各个进口方向上的车流量需要；同时在城市道路网络中各种各样的交通流（机动车，非机动车，行人）在此相互交叉通过、分流转向，可见交叉口是城市道路网络最为重要的位置。但交叉口也是交通堵塞和交通事故的多发地点。城市道路运输机动车的效率、道路安全度、交叉口通行能力、道路的服务水平对环境和能源的影响基本上取决于城市道路交叉口的通行能力。

在对城市道路交叉口中控制和优化中最为常见的是信号控制，在信号控制中单点信号交叉口是城市道路控制与优化的基础。对城市道路交叉口进行科学合理的信号控制与优化，是提高城市交叉口的交通安全和通行能力、减少交叉口停车

延误的有效措施，可以缓解城市拥堵的交通问题。

对城市道路交叉口信号进行控制优化的方法模型进行说明，介绍了交通信号灯控制的基本方法，熟悉介绍交通信号管理软件synchro的相关功能和仿真情况，以synchro为工具进行城市道路区域的协调控制，对城市道路区域协调控制模型进行介绍！以呼和浩特城市道路为例，通过对呼和浩特道路现状交通的分析调查，运用交通管理软件synchro进行仿真，通过对仿真结果的分析结合呼和浩特现在的道路状况，得到现状道路所存在的交通问题，通过对问题的分析，提出相应的优化方案，然后运用synchro对优化后的交通情况进行仿真，对比评价仿真结果，提出优化方案。对城市交通信号问题进行优化，挺高城市交通道路的通行能力！完善城市交通的基础设施！

本论文通过对城市道路交叉口交通信号的控制的说明，介绍了交通信号灯控制的基本方法，引出了城市道路交通信号区域控制，通过对城市交通信号区域控制的介绍，提出了对城市道路交通信号区域进行分级控制优化的方法模型。

本论文通过对交通信号仿真优化软件synchro6.0各个功能的介绍，软件优化模型及各评价指标的计算方法与模型的相关介绍。基于呼和浩特市新城区，以新城区新华大街为主干道进行城市道路主干道交通信号控制与优化仿真。通过对新华大街与锡林郭勒北路，新华大街与迎宾北路，新华大街与呼伦贝尔北路各个交叉口交通信号配时方案，道路属性，交通量等进行调查，通过对调查数据进行处理研究，运用交通信号控制仿真软件synchro6.0进行交通现状的仿真，然后再对新华大街主干道信号配时方案进行优化，对优化结果进行仿真，进行评价然后进行优化前后的仿真对比。说明道路主干道控制优化的优点。由于本次设计时间较短，加上本人在这方面的学习研究还有待提高，所以本论文只能简单地介绍相关的设计方法和模型，对于更加复杂交错的交叉口还有待进一步的学习和研究。

总体来说，Synchro系统对信号交叉口的配时方案及优化程序主要针对交叉口信号周期时长、相位方案和交叉口绿信比等进行总体综合优化。该系统能充分考虑到该区域道路的各项性质（交叉口范围内的公交站点、公共交通的影响，交叉口范围内的路边停车、自行车和行人等各种外在因素对交叉口通行能力和服务水平的影响，其适用能力强，是一种专业针对信号交叉口使用较为简便的信号控制优化配时软件。

道路交叉口停车计算与交叉口延误的计算方法相同。在交叉口进口道产生停

车延误的车辆数与排队车辆数相同，如上图中的Q。同时Synchro系统认为10s以内延误的车辆没有完全停车，对这些车辆，Synchro通过计算每个车辆每次在进口道延误的时间，对延误在10s以内的车辆按照定好的相应比例确定停车数。

由于新华大街各个交叉口相距很近，使得交叉口与交叉口之间的车容量较小，而且各个交叉口之间的信号灯周期时长不同，不能进行关联管理，亦使得新华大街不能进行绿波交通控制。对各个交叉口信号周期进行优化后，可以显著提高交叉口的服务水平，且可以对新华大街主干道进行联动控制，大大的减小了新华大街主干道上的延误

在这段时间里，我通过对交通信号管理与仿真软件 synchro的不断熟悉与运用，逐渐深入的了解到了交叉口交通信号对城市道路交通的重要性！交通信号对于缓解现在各个城市道路拥挤的重要性，在这段时间里，我通过对呼和浩特新城区新华大街主干道道路情况和各个交叉口的交通情况的调查与统计，发现可以运用交通信号管理软件synchro对各个交叉口进行优化仿真，可以使新华大街主干道进行“线控制“,进而提高新华大街主干道各个交叉口的通行能力。

Synchro in traffic control and the design application

In city of smaller area, within the area can be controlled all the intersection;In the city of large region, can region partition of hierarchical control.The division of the results often make level control into one by the few line of control the grading of centralized control system, at this moment, you may think that makes the control is the surface control a unit;Sometimes the division of the results is to become a point, line, face the comprehensive control of hierarchical control system.Now on the city road for regional coordination control is dividing the multilevel more signal control branch area, the son of signal area for coordinated control, optimizing the management control signal branch area, and then to the road for regional coordination control to achieve the purpose of the whole city road optimization.The urban road is divided into more signal control branch area, also is the city road junction lines to the traffic signal coordination control, the city is divided into more massive control, and each intersection on running for linkage control, at the same time, to a single intersection signal control optimization and at the same time to consider all the linkage of the massive upstream and downstream intersection control.Each intersection running according to design signal timing formula for operation, make the vehicle into the city intersection, not often meet with red light, called city intersection signal coordination control, known as the ”green wave“ signal control.City single point as a city intersection traffic network in the important part of urban road traffic problems as the key point.City intersection of single point, evaluation standard reference index: crossing capacity, the import of saturation, the way the intersections, intersection delay import way parking import stops, import way way queue length and the car fuel consumption, etc.Timing signal intersection control timing method in continuous improvement in, most scholars think both at home and abroad from different evaluation index set out, can adopt different kinds of optimization algorithm for other, more reasonable timing method.According to the plane intersection traffic control way without control can be divided into the intersection, massive priority control signal intersection control, intersection, ring intersection of several types.Massive priority intersection control, is on the way in time set the right-of-way or slow down the right-of-way parking sign, instruction time road vehicles must stop or slow down to the right-of-way vehicles running a traffic control method.Intersection of road network traffic capacity is in the ”bottleneck“ and traffic accidents ”black spots“.The traffic jam main cities at home and abroad to the hair in the intersection, causing traffic disruption, more accidents, delay serious.Such as Japan cities in motor vehicle in the city center of about a third of the travel time spent on plane intersection.At the same time, the intersection of the traffic accident is the main sources.The United States about half the traffic accident happened in the intersection;The federal Germany on the road traffic accident about thirty-six percent to the hair in the intersection, city in the traffic accident happened about sixty percent to eighty percent in the intersection and its nearby.Therefore, the intersection traffic accident ”was“ not aroused people's concern.How to carry out the scientific management of city intersection of this section is to talk

about the problem.Implementation of the control mode depends on the geometrical characteristics of the intersection and traffic conditions the purpose is to ensure the intersection of traffic safety and and give full play to the crossing capacity.This section mainly intersections is given priority to, to discuss all to no control intersection and massive priority intersection control, and briefly introduced the basic points of modern ring intersection.The single intersection control strategy of the upstream and downstream will road intersection traffic produce very big effect, intersection upstream and downstream the closer the greater the traffic flow, the greater the effect will be.The traffic signal ”point control" is to separate out the intersection of the separate analysis, and carry on the single signal optimization and road control strategy, and don't consider the intersection of the upstream and downstream the influence of the intersection.The urban road traffic signal control is the study of the regional coordination in a city way way zone, to each road intersections of signal period of how long, how intersection green than and between the letter at phase difference is optimized, to minimize the intersection delay parking, improve the urban road network capacity traffic signal control method coordination area.Along with the urban road area signal coordination control the development of the theory, the researchers found that, can be to a larger city road traffic area network as a great whole, the traffic signal coordination control and optimization, as a result of road network and the complexity of the flow of motor vehicles, but for the optimization results to the travel of the ability is not very ideal.Therefore, since the 1970 s, many researchers began to try to be huge, complex tedious road network according to certain principles and methods model division, divided into several signal control branch area, and then again to signal control subdomain coordinate signal control, to improve the way of city road network coordination control effect.At present, the urban road traffic congestion problem has been become the attention and to the world.City road and intersection traffic as a city of basic services, mainly including road intersection and sections, the service performance in good operating directly affect the normal operation of city traffic.City road crossing the road system is an important component of the urban road through the intersection nodes to the various factors of city road connect each other of road network, to coordinate each intersection on the direction of imported cars need;At the same time in the city road network all kinds of traffic flow(motor vehicle, the motor vehicle, pedestrians)in the cross each other through the shunt turned, visible intersection of city road network is the most important position.But the intersection is traffic and traffic accidents of the multiple sites.City road transport vehicle efficiency, road safety degree, intersection traffic capacity, the service level of the road to the environment and the influence of the energy basically depends on the urban road crossing capacity.In the urban road intersections control and optimization of the most common is the signal of control, signal control of a single point signal intersection control and optimization of city road is based.City road intersection of scientific reasonable signal control and optimization, is to improve the city traffic safety and the intersection traffic capacity, reduce the effective measures to stop intersection delay, can ease congestion

第五篇：建筑学本科毕业设计外文翻译

本科毕业设计外文翻译 题目： 德黑兰城市发展

学 院: 专 业: 学 号: 学生姓名: 指导教师:

城市建设学院 建筑学

日 期: 二零一一年六月

First Chapter：Development of the city of Tehran

Ali Madanipour 武汉科技大学本科毕业设计外文翻译

Tehran :the making of a metropolis，First Chapter：Development of the city of Tehran，Ali Madanipour，ISBN：0471957798，Press： New York John Wiley，1998，page five to page eleven。

第一章：德黑兰市的发展

阿里.马丹妮普尔

德黑兰：一个大都市的建造，第一章：德黑兰市的发展，阿里.马丹妮普尔，书号：0471957798，纽约John Wiley出版社，1998，第五页到第十一页。

德黑兰市的发展

全市已长成了一定的规模性和复杂性，以这样的程度，空间管理需要另外的手段来处理城市组织和不断发展的复杂性，并为城市总体规划做准备。

第二次世界大战后，在盟军占领国家的期间，有一个时期的民主化，在冷战时开始的政治紧张局势之后，它们互相斗争对石油的控制权。这个时期已经结束于1953年，结果 武汉科技大学本科毕业设计外文翻译

是由政变产生了伊朗王，那个后来担任了25年的行政君主的人。随着高出生率和农村向城市迁移，德黑兰和其他大城市增长加剧甚至比以前更快地。到1956年，德黑兰的人口上升到150万，到了1966至300万，1976至450万，其规模也从1934年46平方公里到1976年的250平方公里。

从石油行业的收入增长创造的盈余资源，需要流通和经济的吸收。50年代中期，特别是在工业化的驱动下德黑兰许多大城市有了新工作。20世纪60年代的土地改革释放了大量来自农业的农村人口，这是不能吸收的指数人口增长。这种新的劳动力被吸引到城市：到新的产业，到似乎始终蓬勃发展建筑界，去服务不断增长公共部门和官僚机构。德黑兰的角色是国家的行政，经济，文化中心，它坚定而巩固地通往外面的世界。德黑兰战后的城市扩张，是在管制、私营部门的推动，投机性的发展下进行的。房屋一直供不应求，并有大量可用的富余劳动力和资本，因此在德黑兰建筑行业蓬勃发展，土地和财产的价格不断上涨。这个城市成长为一个在某种意义上道路对外脱节的，城镇和乡村一体化的，郊区不断增长的新的定居点。这加强了社会的孤立性，破坏了郊区的花园和绿地，并使城市管理者的感到无能为力。1962年一位副市长在德黑兰表示：“建筑物和居民点已经满足人们所想要的无论何处何种样子”，创造了一个“事实上城镇相互连接的方式不当”的城市（Nafisi, 1964,第426页）。有许多事情迫切需要做，但市政府并没有法律上或经济上有能力处理这进程。

1966年市政法第一次规定了城规最高委员会的法律体制和土地利用规划公司的综合计划。还有他一系列法律，以支持德黑兰市的新的法律和体制安排，使住房和其他管理工作在城市中发展起来。最重要的一步是策划的德黑兰综合计划于1968年被批准。它是由一个伊朗规划师Fereydun Ghaffari领导下的美国的Victor Gruen和伊朗的Aziz Farmanfarmaian所共同产生的（Ardalan，1986）。该计划确定的城市的问题是：城市密度过高特别是城市中心、主要道路沿线商业活动的膨胀、污染、不完善的基础设施，贫困地区广泛的失业和低收入群体不断地迁移到德黑兰。解决的办法是城市自然社会和经济结构的转型。(Farmanfarmaian and Gruen, 1968).不过该提案大多主张形态上的变化，试图强调一个现代化的理念，强加这个复杂的都市的秩序。设想这个城市的未来可向西形成一个线性多中心的形式，减少密度和市中心的挤塞情况。全市将形成10个地区，其他各区由绿化带隔开，每个地区约50万居民，并设置拥有高楼的商业及工业中心。各个地区（mantagheh）将分为若干区域（nahyeh）和社区（mahalleh）。每个区域人口约1.5到3万，有一所中学和商业中心以及其他必要设施。每个社区有大约5000居民，有一所小学和一个当地的商业中心。这些地区和区域将有相连的交通运输网络，包括高速公路，捷运路线及巴士路线。过境路线的站点会迅速发展为活动度高居住密度高的节点。重建及改善计划中将有60万人离开中心地区(Farmanfarmaian and Gruen, 1968).。

几乎所有这些措施可以追溯到那个拥有时尚规划理念的时代，这主要是受英国新城镇的影响。在Victor Gruen的《我们城市的心脏》（1965）书中，曾设想未来的中心大 武汉科技大学本科毕业设计外文翻译

都市会由10个城市包围，每个国家都有它自己的中心。这很像Ebenezer Howard’s（1960年，第142页）提到的，那个四周被园林城市群包围着的中心城市：“社会的城市”。在德黑兰的规划中，这一概念的直译版被使用。另一个在英国新城镇被使用的概念，比如Redditch和 Runcorn，是把公共交通路线作为城市的骨架的重要性，其停车点是它的重点服务中心。使用邻里中心和小学来限制邻里单元人口，这被广泛应用于这些新市镇，这是一个曾在20世纪20年代在美国发展的想法(Mumford, 1954)。这些思想依然存在，但是，主要是在纸面上。该计划已执行，已在美国城市规划中有根深蒂固的想法，包括了用高速公路网的不断延伸去连接城市的脱节部分;在不同地区的社会管理和物理性质的基础上进行区划;引进容积率的控制发展的密度。

在20世纪70年代进行的其他主要规划工作包括Shahrak Gharb的局部发展新城镇，以及Shahestan依照英国顾问Llewelyn–Davies提出的规划新的城市行政中心，虽然这被当做正在上升的革命浪潮后来从未实施过。

革命和后革命时期可分为三个阶段：革命（1979-1988年），重建（1989-1996年）和改革（1997-2004），每个都展示了德黑兰城市规划中不同的做法。

德黑兰和其他城市经过两年大量实证，1979年有代表性的是一个革命的到来推翻了伊朗君主，由议会共和制和神父统治的不稳定结合所取代。其原因可以追溯到在国王的发展模式导致了许多冲突，现代与传统，经济发展与政治发展，全球市场力量和地方资产阶级力量，外国势力和民族主义，腐败和自满中坚分子与不满的群众。像1906年的革命一样，许多隐藏意见的累积使1979的革命成为可能。在第一次革命，维新已占了上风，而在第二次，传统主义者赢得了领导。然而，无论革命的态度还是他们掌握政权之后的一系列重大问题，包括城市发展都显示出现代化的偏好。从这个意义上讲，该国的这两个爆炸革命事件可以被看作是在动荡中逐步转型所作的努力（Madanipour，1998，2003）。革命是在与伊拉克长期战争（1980-1988）之后，其间停止了经济的发展。在城市发展方面的投资减少，而农村地区和省城受到革命政府的青睐，同时遏制从农村向城市迁移并与大城市公平对待。在此期间主要规划干预是对白天城市中心的私家车活动的限制。同时，战争和新政府的免费或低费用的设施，吸引了更多的人承诺向首都城市移民，到1986年人口达600万。从20世纪50年代城市人口的增长速度已开始减慢，而直到80年代中期首都的增长都更快，但是它的增长率也开始下降（Khatam, 1993）。在革命和战争后，正常化和重建时期开始了，其中大部分持续到上世纪90年代。这期间见证了德黑兰城市规划的若干努力。但是没有一个有效的框架来管理剧烈的城市发展。综合计划在革命后遭到攻击，因为它被认为无法适应变化。1998年，市长批评它主要是形态上的发展规划、植根于前政权的政治框架、并没有足够重视实际操作问题（Dehaghani，1995）。

综合计划的25年寿命在1991年结束。一个伊朗顾问公司（A-Tech）受委托于1985年筹备1986-1996期间的规划。经过多次延迟，在1993年，该计划最终被城市规划高级理事会批准。该计划还注重增长的管理和线性空间战略，利用了城市区域，次区域，地 武汉科技大学本科毕业设计外文翻译

区，小区和邻里尺度。它促进保护、权力下放、多中心发展，有五个卫星新市镇，并发展住宅增加城市密度。该协会建议，城市在5个亚区中被划分成22个区，每个区都拥有自己的服务中心（Shahrdari-e Tehran, 2004）。

1993年的计划不受市政当局欢迎，不同意它的估价和优先次序，认为它不现实、昂贵、无法实施。1996-2001年期间市政当局自己做了一个战略规划，它被认为是德黑兰市政的第一个规划或是德黑兰80。它强调对一个城市提出战略和政策来实现他们的第一个规划，而不是以介绍土地利用规划为目标。它把城市的主要问题确定为能提供服务的资源短缺、城市发展模式和速度、环境污染、缺乏有效的公共交通工具、效率低下和官僚主义。然后市政府对城市的未来远景概述了六个主要特征：一个清洁的城市，建设便于运动的城市公园和绿化带，新的文化和体育设施，改革发展的城市组织，以及对城市空间的改善，包括土地利用和保护的全面和详细的计划的编制规划(Shahrdari-e Tehran, 1996)。

全市实施了1968年的计划中提出的一部分建议，诸如增加南方的绿色开放空间，或是兴建高速公路网;开放城市的大部分地区使之得到新的发展以缓解全城的运作。继承1993年计划的意见，市政府放宽容积率限制，并允许热闹地带有更高的密度。然而，这并非基于规划的考虑，主要是为了使市政当局的财政独立。这在发展产业区广受欢迎，但受到公民的争议。开发者可以通过向市政府缴纳罚款建立更高的建筑物，而不必考虑对周围环境的影响，这个政策俗称“密度销售”。该城市的面貌，特别是在其北部地区，是在短期内改变的，其中包括中通过宽阔的街道和高速公路连接高楼大厦。在较贫穷的南部，一个大型的重建项目Navab穿过密集而破旧的建筑物建造高速公路，建立庞大的上层建筑的各个方面。这个城市的行政边界扩大了两次，一次向外，一次向西，涵盖了700平方公里的22个区市。

这个时期的重建争议随着民主的改革而产生，它重新启动了城市市议会的选举，这首先造成了市长和市政府关系的制度混乱。该会于2001年公布了自己的城市构想作为德黑兰宪章，这总结了大会上安理会成员、非政府组织和市政专家之间原则上同意的问题。该宪章主要采纳了可持续性和民主性原则，被用于开发自然和处理环境、交通、社会、文化、经济问题、城市管理战略、区域性城市，国家和国际角色。

Development of the city of Tehran The city had grown in size and complexity to such an extent thatits spatial managementneeded additional tools, which resulted in the growing complexity of municipalorganization, and in the preparation of a comprehensive plan for the city.After the Second World War, during which the Allied forces occupied the country, there was a period of democratization, followed by political tensions of the start of the cold war, 武汉科技大学本科毕业设计外文翻译

and struggles over the control of oil.This period was ended in 1953 by a coup detat that returned the Shah to power, who then acted as an executive monarch for the next 25 years.With high birth rates and an intensification of rural–urban migration, Tehran— and other large cities—grew even faster than before.By 1956, Tehran’s population rose to 1.5 million, by 1966 to 3 million, and by 1976 to 4.5 million;its size grew from 46 km² in 1934 to 250 km² in 1976(Kariman, 1976;Vezarat-e Barnameh va Budgeh, 1987).Revenues from the oil industry rose, creating surplus resources that needed to be circulated and absorbed in the economy.An industrialization drive from the mid-1950s created many new jobs in big cities, particularly in Tehran.The land reforms of the 1960s released large numbers of rural population from agriculture, which was not able to absorb the exponential demographic growth.This new labour force was attracted to cities: to the new industries, to the construction sector which seemed to be always booming, to services and the constantly growing public sector bureaucracy.Tehran’s role as the administrative, economic, and cultural centre of the country, and its gateway to the outside world, was firmly consolidated.Urban expansion in postwar Tehran was based on under-regulated, private-sector driven, speculative development.Demand for housing always exceeded supply, and a surplus of labor and capital was always available;hence the flourishing construction industry and the rising prices of land and property in Tehran.The city grew in a disjointed manner in all directions along the outgoing roads, integrating the surrounding towns and villages, and growing new suburban settlements.This intensified social segregation, destroyed suburban gardens and green spaces, and left the city managers feeling powerless.A deputy mayor of the city in 1962 commented that in Tehran, ‘‘the buildings and settlements have been developed by whomever has wanted in whatever way and wherever they have wanted’’, creating a city that was ‘‘in fact a number of towns connected to each other in an inappropriate way’’(Nafisi, 1964, p.426).There was a feeling that something urgently needed to be done, but the municipality was not legally or financially capable of dealing with this process.The 1966 Municipality Act provided, for the first time, a legal framework for the formation of the Urban Planning High Council and for the establishment of land-use planning in the form of comprehensive plans.A series of other laws followed, underpinning new legal and institutional arrangements for the Tehran municipality, allowing the Ministry of Housing and others to work together in managing the growth of the city.The most important step taken in planning was the approval of the Tehran Comprehensive Plan in 1968.It was produced by a consortium of Aziz Farmanfarmaian Associates of Iran and Victor Gruen Associates of the 武汉科技大学本科毕业设计外文翻译

United States, under the direction of Fereydun Ghaffari, an Iranian city planner(Ardalan, 1986).The plan identified the city’s problems as high density, especially in the city centre;expansion of commercial activities along the main roads;pollution;inefficient infrastructure;widespread unemployment in the poorer areas, and the continuous migration of low-income groups to Tehran.The solution was to be found in the transformation of the city’s physical, social and economic fabric(Farmanfarmaian and Gruen, 1968).The proposals were, nevertheless, mostly advocating physical change, attempting, in a modernist spirit, to impose a new order onto this complex metropolis.The future of the city was envisaged to be growing westward in a linear polycentric form, reducing the density and congestion of the city centre.The city would be formed of 10 large urban districts, separated from each other by green belts,each with about 500,000 inhabitants, a commercial and an industrial centre with high-rise buildings.Each district(mantagheh)would be subdivided into a number of areas(nahyeh)and neighborhoods(mahalleh).An area, with a population of about 15–30,000, would have a high school and a commercial centre and other necessary facilities.A neighborhood, with its 5000 inhabitants, would have a primary school and a local commercial centre.These districts and areas would be linked by a transportation network, which included motorways, a rapid transit route and a bus route.The stops on the rapid transit route would be developed as the nodes for concentration of activities with a high residential density.A number of redevelopment and improvement schemes in the existing urban areas would relocate 600,000 people out of the central areas(Farmanfarmaian and Gruen, 1968).Almost all these measures can be traced to the fashionable planning ideas of the time, which were largely influenced by the British New Towns.In his book, The Heart of Our Cities, Victor Gruen(1965)had envisaged the metropolis of tomorrow as a central city surrounded by 10 additional cities,each with its own centre.This resembled Ebenezer Howard’s(1960, p.142)‘‘social cities’’, in which a central city was surrounded by a cluster of garden cities.In Tehran’s plan, a linear version of this concept was used.Another linear concept, which was used in the British New Towns of the time such as Redditch and Runcorn, was the importance of public transport routes as the town’s spine, with its stopping points serving as its foci.The use of neighborhood units of limited population, focused on a neighborhood centre and a primary school, was widely used in these New Towns, an idea that had been developed in the 1920s in the United States(Mumford, 1954).These ideas remained, however, largely on paper.Some of the plan’s ideas that were implemented, which were rooted in American city planning, included a network of freeways to connect the disjointed 武汉科技大学本科毕业设计外文翻译

parts of the sprawling metropolis;zoning as the basis for managing the social and physical character of different areas;and the introduction of Floor Area Ratios for controlling development densities.Other major planning exercises, undertaken in the 1970s, included the partial development of a New Town, Shahrak Gharb, and the planning of a new administrative centre for the city—Shahestan—by the British consultants Llewelyn–Davies, although there was never time to implement the latter, as the tides of revolution were rising.Planning through policy development: reconstruction after the revolution and war The revolutionary and post-revolutionary period can be divided into three phases: revolution(1979–1988), reconstruction(1989–1996), and reform(1997–2004), each demonstrating different approaches to urban planning in Tehran.After two years of mass demonstrations in Tehran and other cities, the year 1979 was marked by the advent of a revolution that toppled the monarchy in Iran, to be replaced by a state which uneasily combined the rule of the clergy with parliamentary republicanism.Its causes can be traced in the shortcomings of the Shah’s model of development, which led to clashes between modernization and traditions, between economic development and political underdevelopment, between global market forces and local bourgeoisie, between foreign influence and nationalism, between a corrupt and complacent elite and discontented masses.Like the revolution of 1906, a coalition of many shades of opinion made the revolution of 1979 possible.In the first revolution, the modernizers had the upper hand, while in the second the traditionalists won the leadership.However, the attitudes of both revolutions—and the regimes that followed them—to a number of major issues, including urban development, show a preference for modernization.In this sense, both revolutions can be seen as explosive episodes in the country’s troubled efforts at progressive transformation(Madanipour, 1998, 2003).The revolution was followed by a long war(1980–1988)with Iraq, which halted economic development.Investment in urban development dwindled, while rural areas and provincial towns were favoured by the revolutionary government, both to curb rural–urban migration and to strike a balance with large cities.The key planning intervention in this period was to impose daytime restrictions on the movement of private cars in the city centre.Meanwhile, the war and the promise of free or low-cost facilities by the new government attracted more migrants to the capital city, its population reaching 6 million by 1986.The rate of population growth in the city had started to slow down from the 1950s, while the metropolitan region was growing faster until the mid-1980s, when its growth rate also started to decline(Khatam, 1993).After the revolution and war, a period of normalization and reconstruction started, which 武汉科技大学本科毕业设计外文翻译

lasted for most of the 1990s.This period witnessed a number of efforts at urban planning in Tehran.Once again, urban development had intensified without an effective framework to manage it.The comprehensive plan came under attack after the revolution, as it was considered unable to cope with change.In 1998, the Mayor criticized it for being mainly a physical development plan, for being rooted in the political framework of the previous regime, and for not paying enough attention to the problems of implementation(Dehaghani, 1995).The comprehensive plan’s 25-year lifespan came to an end in 1991.A firm of Iranian consultants(A-Tech)was commissioned in 1985 to prepare a plan for the period of 1986–1996.After much delay, it was only in 1993 that the plan was finally approved by the Urban Planning High Council.This plan also focused on growth management and a linear spatial strategy, using the scales of urban region, subregion, district, area and neighbourhood.It promoted conservation, decentralization, polycentric development, development of five satellite new towns, and increasing residential densities in the city.It proposed that the city be divided into 22 districts within five sub-regions, each with its own service centre(Shahrdari-e Tehran, 2004).The 1993 plan was not welcomed by the municipality, which disagreed with its assessments and priorities, finding it unrealistic, expensive, and impossible to implement.The municipality produced its own strategic plan for the period 1996–2001, known as Tehran Municipalty’s First Plan, or Tehran 80.Rather than introducing a land-use plan as its goal, this was the first plan for the city that emphasized a set of strategies and propose d policies to achieve them.It identified the city’s main problems as shortage of resources to deliver its services;the pace and pattern of urban growth;environmental pollution;the absence of effective public transport, and inefficient bureaucracy.The municipality’s vision for the future of the city was then outlined to have six major characteristics: a clean city, ease of movement in the city, the creation of parks and green spaces, the development of new cultural and sports facilities, reform of the municipal organization, and planning for the improvement of urban space, including preparation of comprehensive and detailed plans for land use and conservation(Shahrdari-e Tehran, 1996).The municipality implemented part of the proposals, such as increasing the amount of green open spaces in the south, or constructing new parts of the motorway network, which was proposed by the 1968 plan;opening large parts of the city to new development, and easing movement across the city.Following the advice of the 1993 plan, the municipality relaxed FAR limits and allowed higher densities through bonus zoning.This, however, was not based on planning considerations, but was mainly to bring financial autonomy to the municipality.This proved to be popular with the development industry, but controversial with citizens.Developers could build taller buildings by paying fines to the municipality, in a 武汉科技大学本科毕业设计外文翻译

policy popularly known as ‘‘selling density’’, without having to show their impacts on the surrounding environment.The face of the city, particularly in its northern parts, was transformed in a short period, consisting of medium to high-rise buildings connected through wide streets and motorways.In the poorer south, a major redevelopment project, Navab, cut a motorway through the dense and decayed fabric, building gigantic superstructures on each side.The city’s administrative boundaries were expanded twice, once outward and then westward, to encompass 22 district municipalities in 700 km².This controversial period of reconstruction was followed by a period of democratic reform, which re-launched an elected city council for the city, which at first caused institutional confusion about its relationship with the mayor and the municipality.The council published its own vision of the city as Tehran Charter in 2001, which was the summary of the principles agreed between council members, non-governmental organizations, and urban experts at a congress about the subject.The Charter adopted sustainability and democracy as its key principles, which were used to develop strategies for natural and built environments, transport, social, cultural and economic issues, urban management, and the city’s regional, national and international roles.