毕业设计(论文)外文
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题目: 概述
院系名称：信息科学与工程学院
专业班级：计算机科学与技术05级6班
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概述
当ASP第一次发布时，Web编程还比较困难，因为需要IIS来处理ASP页。后来，和Visual Studio?2005通过引入网站开发模型使一切工作都变得容易了。借助该网站模型，您不必在Visual Studio 中创建新项目，而是可以指向一个目录并开始编写网页和代码。此外，您还可以使用内置的Development Server快速测试站点，Development Server将寄宿在一个本地进程中，并消除了必须安装IIS才能进行开发这一先决条件。下面从不同的方面来介绍技术。
类库
是微软.NET framework整体的一部分,它包含一组大量编程用的类，满足各种编程需要。因为Visual Basic、JScript和C++这些编程语言的很多功能具有重叠性。举例来说，对于每一种语言，你必须包括存取文件系统、与数据库协同工作和操作字符串的方法。此外，这些语言包含相似的编程构造。都能够使用循环语句和条件语句。即使用Visual Basic写的条件语句的语法和用C++的不一样,程序的功能也是相同的。对于多种语言来说维持这一功能需要很大的工作量。那么对所有的语言创建这种功能一次，然后把这个功能用在每一种语言中岂不是更容易。然而.NET类库不完全是那样。它含有大量的满足编程需要的类。举例来说，.NET类库不仅包含处理数据库访问的类和文件协同工作，操作文本和生成图像，而且还包含更多特殊的类用在正则表达式和处理Web协议。此外.NET framework，也包含支持所有的基本变量数据类型的类，比如：字符串、整型、字节型、字符型和数组。
.NET framework是庞大的。它包含数以千计的类。(超过3,400)幸运地是，类不是简单的堆在一起。.NET framework的类被组织成有层次结构的命名空间。
一个命名空间包含一组逻辑的类。举例来说，涉及到与文件系统协同工作的类就集合在命名空间中。命名空间被组织成一个层次结构(一棵逻辑树)。树根就是SYSTEM 命名空间。这个命名空间包含基本的数据类型的所有的类,例如：字符串、数组，还包含提供随机数字和日期的类。
你通过完整的类的命名空间能唯一识别任何的类在.NET framework中的位置。例如,指定找到一个the File class类，按如下操作:
.文件
指命名空间，而文件指定特定的类。
在默认情况下，在你的页面中，类被包含在一个选定的命名空间中这些默认的命名空间使你在中最常用到的。
System命名空间-包含所有的基本数据类型和其他有用的类，例如：那些关于产生随机数字和日期的类。
命名空间-包含的类是标准的集合类，例如：哈希表，数组列表。
命名空间-包含特殊的集合类，例如：连接列表和字符串集合。
命名空间-包括files类。
命名空间-包含编码，解码和操作字符串内容的类。
命名空间-包含的是匹配正则表达式和替代操作类。
命名空间-工作在万维网方面包含的是浏览器请求和服务器响应的类。
命名空间-包含页面缓冲内容和自定义缓冲操作的类。
命名空间-包含执行验证和授权，例如：窗体和密码验证的类。
命名空间-包含执行保存状态的类。
命名空间-包含构建页面的用户接口的类。命名空间-包含HTML控件的类。
命名空间-包含Web控件的类。
.Net支持C#,,C++和Visual Basic中的任一种语言作为你的编程语言来完成程序编写。但不管你使用什么语言开发页面，你需要明白在执行前必须编译，这就意味着执行速度非常快。第一次请求页面,页面被编译成一个.NET类,这个类文件被保存在一个特殊的目录下，这个目录的名字叫Temporary Files。对于一个页面一个通信类文件也会出现在Temporary Files目录下。以后不管任何时候你请求那个同样的页面，那个通信类文件就会执行。当页面被编译的时候，它没被直接地被编译成机器码而是被编译成了一个中间语言，名字叫MSIL，所有.NET可用的语言都被编译成这种中间语言。一个页面不会被编译成本地机器码直到它被一个浏览器访问，在那个时间点包含在Temporary Files目录下的类文件用JIT编译器编译并且执行。这些迷惑的方面体现在整个过程中且都在后台运行，你必须要做的是用资源代码为你的页面创建一个文本文件。
2.用Web服务器控件创建窗体
用几个基本Web控件来代替标准的HTML窗体元素，例如radiobuttons、textboxes, and listboxes.在Web应用程序中可以用这些控件创建用户界面。
3.用验证控件做页面验证
传统地，当增加验证到页面中时，会面临一个严峻的选择。你可以添加窗体页面验证规则到你的服务器端代码，也可以添加验证规则到你的客户端代码。
写验证代码到客户端代码中的优势能够及时反馈到你的用户。例如，一个使用者忽略输入一个要求检验的字段，你能够及时的显示一个错误信息而不需要返回到服务器端解决。人们喜欢客户端的验证。它能产生一种很好的效果。然而，问题是它不与所有的浏览器兼容。不是所有的浏览器支持JavaScript、不同版本的浏览器的不同版本支持JavaScript，所以客户端验证没有保障。由于这个原因，许多开发者决定添加自定义验证到服务器端。因为服务器端代码能够和任何浏览器协同工作。这样的做法是更有安全保障。同时这些验证控件会自动地产生客户端代码和服务器端代码。如果一个浏览器有能力支持JavaScript，客户端的验证脚本将会自动返回到浏览器。如果一个浏览器不支持JavaScript，那个验证规则会自动在服务器端代码中执行。
控制字段:RequiredFieldValidator控件
你可以用这个控件来检查在一个Web窗体中是否为空，典型地，你和TextBox控件一起使用这个控件。然而，这个控件也可以和其他的输入型控件结合使用，例如：RadioButtonList控件。
验证表达式:RegularExpressionValidator控件
你能使用RegularExpressionValidator控件来验证输入的值是否和定义的正则表达式相匹配。例如：你能使用这控件来检查一个用户是否输入一个合法的电子邮件地址，电话号码，用户名或密码。
比较值:CompareValidator控件
这个CompareValidator 控件用于比较一个输入的数据和另外一个值是否相同。另外一个值可能是固定值，例如：一个特定的数字或者是输入到另一个控件中的一个值。总结错误:ValidationSummary控件
假想一个页面有50个字段假如你仅仅用上部分讨论的那些验证控件来显示错误看见一个错误在页面中将是很难的。例如：你可能需要滚动到第48个页面字段来找到这个错误信息。
幸好，微软除了包含上面提到的控件还包括ValidationSummary控件。你能用这个控件综合所有的错误信息在一个页面的上端或者你想要的任何一个地方。
4.先进的控件编程
保存浏览状态
默认地，几乎所有的控件都会在先前的窗体中保留他们的属性值。举例来说，如果你输入文本到一个Lebel标签上然后提交那个页面，当那个页面再次被访问时那个Lebel标签的内容将会被保存下来。浏览状态的妙处是它不依赖任何的特定服务器或浏览器的属性。尤其，它不依赖cookies,session变量、或应用程序变量。浏览状态在一个名叫做VIEWSTATE的隐藏页面中执行，这个隐藏页面自动创建每个Web窗体。当应用时,浏览状态能够在你的网站中产生艺术性的积极效果，例如：你在一个支持浏览状态的控件中显示数据库数据，你不需要每次都返回到需要反馈到服务器的数据库页面。它能够自动地保存页面里的数据状态。
显示和隐藏内容
假想把一个form变成很多页面，以便一个人每次只看那个form的一个部分。
可以设置单个控件和一组控件的Visible and Enabled属性来隐藏和显示页面内容。
使用Visible and Enabled属性
每个控件,包括HTML和Web控件,有一个Visible 属性来决定那个控件是否可见。当一个控件的Visible是false值，那个控件就不会在页面上显示；那个控件也不会进一步运行。
Web控件(不是每个HTML控件)还有一个叫Enabled的属性。当Enabled的属性是false 值，你用的浏览器是或更高的版本那个控件被封住了，也不起作用了，当用其他的浏览器的时候，如：网景浏览器那个控件不会被封，但它也是不起作用的。
部署项目
的魅力在于您在开发Web应用程序时无需考虑打包和部署。当需要其他类时可向App_Code目录添加一个.cs文件即可开始编写。当希望将可本地化的字符串存储在资源文件中时，可向App_GlobalResources目录添加一个.resx文件并键入字符串。一切都顺顺当当，根本就不必考虑编译和部署方面的事情。
在准备进行部署时，有多种可选方案。最简单的方案是将文件复制到主运行服务器并按要求编译每一个文件（和在测试环境中一样）。第二种方案是使用实用工具将应用程序预编译为二进制版本，之后将只剩下要放到服务器上的一组程序集、静态内容和配置文件。第三种方案也使用，但要创建一个可更新的二进制部署，其中.as*x文件保持不变（并且可修改），而所有代码文件都编译为二进制程序集。
6. C#语言
C# 是一种简洁、类型安全的面向对象的语言，开发人员可以使用它来构建
在.NET Framework 上运行的各种安全、可靠的应用程序。使用C#，您可以创建传统的Windows 客户端应用程序、XML Web services、分布式组件、客户端- 服务器应用程序、数据库应用程序以及很多其他类型的程序。Microsoft Visual C# 2005 提供高级代码编辑器、方便的用户界面设计器、集成调试器和许多其他工具，以在C# 语言版本和.NET Framework 的基础上加快应用程序的开发。
C# 语法表现力强，只有不到90 个关键字，而且简单易学。C# 的大括号语法使任何熟悉C、C++ 或Java 的人都可以立即上手。了解上述任何一种语言的开发人员通常在很短的时间内就可以开始使用C# 高效地工作。C# 语法简化了C++ 的诸多复杂性，同时提供了很多强大的功能，例如可为空的值类型、枚举、委托、匿名方法和直接内存访问，这些都是Java 所不具备的。C# 还支持泛型方法和类型，从而提供了更出色的类型安全和性能。C# 还提供了迭代器，允许集合类的实现者定义自定义的迭代行为，简化了客户端代码对它的使用。
作为一种面向对象的语言，C# 支持封装、继承和多态性概念。所有的变量和方法，包括Main 方法（应用程序的入口点），都封装在类定义中。类可能直接从一个父类继承，但它可以实现任意数量的接口。重写父类中的虚方法的各种方法要求override 关键字作为一种避免意外重定义的方式。在C# 中，结构类似于一个轻量类；它是一种堆栈分配的类型，可以实现接口，但不支持继承。
除了这些基本的面向对象的原理，C# 还通过几种创新的语言结构加快了软件组件的开发，其中包括：
?封装的方法签名（称为委托），它实现了类型安全的事件通知。
?属性(Property)，充当私有成员变量的访问器。
?属性(Attribute)，提供关于运行时类型的声明性元数据。
?内联XML 文档注释。
在C# 中，如果需要与其他Windows 软件（如COM 对象或本机Win32 DLL）交互，可以通过一个称为“Interop”的过程来实现。互操作使C# 程序能够完成本机
C++ 应用程序可以完成的几乎任何任务。在直接内存访问必不可少的情况下，C# 甚至支持指针和“不安全”代码的概念。
C# 的生成过程比C 和C++ 简单，比Java 更为灵活。没有单独的头文件，也不要求按照特定顺序声明方法和类型。C# 源文件可以定义任意数量的类、结构、接口和事件。
C# 程序在.NET Framework 上运行，它是Windows 的一个必要组件，包括一个称为公共语言运行时(CLR) 的虚拟执行系统和一组统一的类库。CLR 是Microsoft 的公共语言基础结构(CLI) 的一个商业实现。CLI 是一种国际标准，是用于创建语言和库在其中无缝协同工作的执行和开发环境的基础。
用C# 编写的源代码被编译为一种符合CLI 规范的中间语言(IL)。IL 代码与资源（如位图和字符串）一起作为一种称为程序集的可执行文件存储在磁盘上，通常具有的扩展名为.exe 或.dll。程序集包含清单，它提供关于程序集的类型、版本、区域性和安全要求等信息。
执行C# 程序时，程序集将加载到CLR 中，这可能会根据清单中的信息执行不同的操作。然后，如果符合安全要求，CLR 执行实时(JIT) 编译以将IL 代码转换为本机机器指令。CLR 还提供与自动垃圾回收、异常处理和资源管理有关的其他服务。由CLR 执行的代码有时称为“托管代码”，它与编译为面向特定系统的本机机器语言的“非托管代码”相对应。下图演示了C# 源代码文件、基类库、程序集和CLR 的编译时与运行时的关系。
语言互操作性是.NET Framework 的一个关键功能。因为由C# 编译器生成的IL 代码符合公共类型规范(CTS)，因此从C# 生成的IL 代码可以与从Visual Basic、Visual C++、Visual J# 的.NET 版本或者其他20 多种符合CTS 的语言中的任何一种生成的代码进行交互。单一程序集可能包含用不同.NET 语言编写的多个模块，并且类型可以相互引用，就像它们是用同一种语言编写的。
除了运行时服务，.NET Framework 还包含一个由4000 多个类组成的内容详尽的库，这些类被组织为命名空间，为从文件输入和输出到字符串操作、到XML 分析、到Windows 窗体控件的所有内容提供多种有用的功能。典型的C# 应用程序使用.NET Framework 类库广泛地处理常见的“日常”任务。
Overview
When ASP was first released, Web programming was more difficult because you needed IIS to serve your ASP pages. Later, and Visual Studio? 2005 made everything easier by introducing the Web site model of development. Instead of creating a new project inside Visual Studio, the Web site model lets you point to a directory and start writing pages and code. Furthermore, you can quickly test your site with the built-in Development
Server, which hosts in a local process and obviates the need to install IIS to begin will introduce technology from different aspects.
.NET Framework Class Library
is part of Microsoft's overall .NET framework, which contains a vast set of programming classes designed to satisfy any conceivable programming Visual Basic, JScript, and C++. A great deal of the functionality of these programming languages example, for each language, you would have to include methods for accessing the file system, working with databases, and manipulating ’s more, these languages con tain similar programming constructs, can represent loops and conditionals. Even though the syntax of a conditional written in Visual Basic differs from the syntax of a conditional written in C++, the programming function is the same. Maintaining all this functionality for multiple languages requires a lot of work. Wouldn't it be easier to create all this functionality once and use it for every language?however, The .NET Framework Class Library does exactly that. It consists of a vast set of classes designed to satisfy any conceivable programming instance, the .NET framework contains classes for handling database access, working with the file system, manipulating text, and generating graphics. In addition, it contains more specialized classes for performing tasks such as working with regular expressions and handling network protocols. furthermore, The .NET framework contains classes that represent all the basic variable data types such as strings, integers, bytes, characters, and arrays.
The .NET framework is huge. It contains thousands of classes (over 3,400). Fortunately, the classes are not simply jumbled together. The classes of the .NET framework are organized into a hierarchy of namespaces.
A namespace is a logical grouping of classes. For example, all the classes that relate to working with the file system are gathered together into the namespace. The namespaces are organized into a hierarchy (a logical tree). At the root of the tree is the System namespace. This namespace contains all the classes for the base data types, such as strings and arrays. It also contains classes for working with random numbers and dates and times.
You can uniquely identify any class in the .NET framework by using the full namespace of the class. For example, to uniquely refer to the class that represents a file system file (the File class), you would use the following:
refers to the namespace, and File refers to the particular class.
The classes contained in a select number of namespaces are available in your pages by default. (You must explicitly import other namespaces.) These default namespaces contain classes that you use most often in your applications: System— Contains all the base data types and other useful classes such as those related to generating random numbers and working with dates and times.
— Contains classes for working with standard collection types such as hash tables, and array lists.
— Contains classes that represent specialized collections such as linked lists and string collections.
— Contains classes for working with configuration files files).
— Contains classes for encoding, decoding, and manipulating the contents of strings.
— Contains classes for performing regular expression match and replace operations.
— Contains the basic classes for working with the World Wide Web, including classes for representing browser requests and server responses.
— Contains classes used for caching the content of pages and classes for performing custom caching operations.
— Contains classes for implementing authentication and authorization such as Forms and Passport authentication.
— Contains classes for implementing session state.
— Contains the basic classes used in building the user interface of pages.
— Contains the classes for the HTML controls.
— Contains the classes for the Web controls.
You can choose C# or or C++ or Visual Basic to program page. regardless of the language that you use to develop your pages, you need to understand that pages are compiled before they are executed. This means that pages can execute very quickly. The first time you request an page, the page is compiled into a .NET class, and the resulting class file is saved beneath a special directory on your server named Temporary Files. For each and every page, a corresponding class file appears in the Temporary Files directory. Whenever you request the same page in the future, the corresponding class file is executed. When an page is compiled, it is not compiled directly into machine code. Instead, it is compiled into an intermediate-level language called Microsoft Intermediate Language (MSIL). All .NET-compatible languages are compiled into this intermediate language. An page isn't compiled into native machine code until it is actually requested by a browser. At that point, the class file contained in the Temporary Files directory is compiled with
the .NET framework Just in Time (JIT) compiler and executed. The magical aspect of this whole process is that it happens automatically in the background. All you have to do is create a text file with the source code for your page.
Forms with Web Server Controls
Useingseveral of the basic Web controls to represent standard HTML form elements such as radio buttons, text boxes, and list boxes. You can use these controls in your pages to create the user interface for your Web application..
Form Validation with Validation Controls
Traditionally, Web developers have faced a tough choice when adding form validation logic to their pages. You can add form validation routines to your server-side code, or you can add the validation routines to your client-side code. The advantage of writing validation logic in client-side code is that you can provide instant feedback to your users. For example, if a user neglects to enter a value in a required form field, you can instantly display an error message without requiring a roundtrip back to the really like client-side validation. It looks great and creates a better overall user experience. The problem, however, is that it does not work with all browsers. Not all browsers support JavaScript, and different versions of browsers support
different versions of JavaScript, so client-side validation is never guaranteed to this reason, in the past, many developers decided to add all their form validation logic exclusively to server-side code. Because server-side code functions correctly with any browser, this course of action was safer. At the same time, The Validation controls automatically generate both client-side and server-side code. If a browser is capable of supporting JavaScript, client-side validation scripts are automatically sent to the browser. If a browser is incapable of supporting JavaScript, the validation routines are automatically implemented in server-side code.
Requiring Fields: The RequiredFieldValidator Control
You use RequiredFieldValidator in a Web form to check whether a control has a value. Typically, you use this control with a TextBox control. However, nothing is wrong with using RequiredFieldValidator with other input controls such as RadioButtonList. Validating Expressions: The RegularExpressionValidator Control
You can use RegularExpressionValidator to match the value entered into a form field
to a regular expression. You can use this control to check whether a user has entered, for example, a valid e-mail address, telephone number, or username or password. Samples of how to use a regular expression to perform all these validation tasks are provided in the following sections.
Comparing Values: The CompareValidator Control
The CompareValidator control performs comparisons between the data entered into a form field and another value. The other value can be a fixed value, such as a particular number, or a value entered into another control.
Summarizing Errors: The ValidationSummary Control
Imagine that you have a form with 50 form fields. If you use only the Validation controls discussed in the previous sections of this chapter to display errors, seeing an error message on the page might be difficult. For example, you might have to scroll down to the 48th form field to find the error message.
Fortunately, Microsoft includes a ValidationSummary control with the Validation controls. You can use this control to summarize all the errors at the top of a page, or wherever else you want.
Control Programming
Working with View State
By default, almost all controls retain the values of their properties between form posts. For example, if you assign text to a Label control and submit the form, when the page is rendered again, the contents of the Label control are preserved. The magic of view state is that it does not depend on any special server or browser properties. In particular, it does not depend on cookies, session variables, or application variables. View state is implemented with a hidden form field called VIEWSTATE that is automatically created in every Web Forms Page. When used wisely, view state can have a dramatic and positive effect on the performance of your Web site. For example, if you display database data in a control that has view state enabled, you do not have to return to the database each time the page is posted back to the server. You can automatically preserve the data within the page's view state between form posts.
Displaying and Hiding Content
Imagine that you want to break the tax form into multiple pages so that a person views only one part of the tax form at a can set the Visible and Enabled properties with individual controls and groups of controls to hide and display page content. Using the Visible and Enabled Properties
Every control, including both HTML and Web controls, has a Visible property that determines whether the control is rendered. When a control's Visible property has the value False, the control is not displayed on the page; the control is not processed for either
pre-rendering or rendering.
Web controls (but not every HTML control) have an additional property named Enabled. When Enabled has the value False and you are using Internet Explorer version or
higher, the control appears ghosted and no longer functions. When used with other browsers, such as Netscape Navigator, the control might not appear ghosted, but it does not function. Deployment Projects
The beauty of the is that you can develop your Web application without thinking about packaging and need another class ,you can Add a .cs file to the App_Code directory and start writing. When want to store localizable strings in a resource file, you can add a .resx file to the App_GlobalResources directory and type in the strings. Everything just works; you don't have to think about the compilation and deployment aspect at all.
When you are ready to deploy, you have several options. The simplest choice is to copy your files to a live server and let everything be compiled on-demand (as it was in your test environment). The second option is to use the utility and precompile the application into a binary release, which leaves you nothing but a collection of assemblies, static content, and configuration files to push to the server. The third option is to again use , but to create an updateable binary deployment where your .as*x files remain intact (and modifiable) and all of your code files are compiled into binary assemblies.
6.C# Language
Introduction to the C# Language and the .NET Framework C# is an elegant and
type-safe object-oriented language that enables developers to build a wide range of secure and robust applications that run on the .NET Framework. You can use C# to create traditional Windows client applications, XML Web services, distributed components,
client-server applications, database applications, and much, much more. Microsoft Visual
C# 2005 provides an advanced code editor, convenient user interface designers, integrated debugger, and many other tools to facilitate rapid application development based on version of the C# language and the .NET Framework.
C# syntax is highly expressive, yet with less than 90 keywords, it is also simple and easy to learn. The curly-brace syntax of C# will be instantly recognizable to anyone familiar with C, C++ or Java. Developers who know any of these languages are typically able to begin working productively in C# within a very short time. C# syntax simplifies many of the complexities of C++ while providing powerful features such as nullable value types,
enumerations, delegates, anonymous methods and direct memory access, which are not found in Java. C# also supports generic methods and types, which provide increased type safety and performance, and iterators, which enable implementers of collection classes to define custom iteration behaviors that are simple to use by client code.
As an object-oriented language, C# supports the concepts of encapsulation, inheritance and polymorphism. All variables and methods, including the Main method, the application's entry point, are encapsulated within class definitions. A class may inherit directly from one parent class, but it may implement any number of interfaces. Methods that override virtual methods in a parent class require the override keyword as a way to avoid accidental redefinition. In C#, a struct is like a lightweight class; it is a stack-allocated type that can implement interfaces but does not support inheritance.
In addition to these basic object-oriented principles, C# facilitates the development of software components through several innovative language constructs, including: ?Encapsulated method signatures called delegates, which enable type-safe event notifications.
?Properties, which serve as accessors for private member variables.
?Attributes, which provide declarative metadata about types at run time.
?Inline XML documentation comments.
If you need to interact with other Windows software such as COM objects or native Win32 DLLs, you can do this in C# through a process called "Interop." Interop enables C# programs to do just about anything that a native C++ application can do. C# even supports pointers and the concept of "unsafe" code for those cases in which direct memory access is absolutely critical.
The C# build process is simple compared to C and C++ and more flexible than in Java. There are no separate header files, and no requirement that methods and types be declared in a particular order. A C# source file may define any number of classes, structs, interfaces, and events.
C# programs run on the .NET Framework, an integral component of Windows that includes a virtual execution system called the common language runtime (CLR) and a unified set of class libraries. The CLR is Microsoft's commercial implementation of the common language infrastructure (CLI), an international standard that is the basis for creating execution and development environments in which languages and libraries work together seamlessly.
Source code written in C# is compiled into an intermediate language (IL) that conforms to the CLI specification. The IL code, along with resources such as bitmaps and strings, is stored on disk in an executable file called an assembly, typically with an extension of .exe or .dll. An assembly contains a manifest that provides information on the assembly's types, version, culture, and security requirements.
When the C# program is executed, the assembly is loaded into the CLR, which might take various actions based on the information in the manifest. Then, if the security requirements are met, the CLR performs just in time (JIT) compilation to convert the IL code into native machine instructions. The CLR also provides other services related to automatic garbage collection, exception handling, and resource management. Code that is executed by the CLR is sometimes referred to as "managed code," in contrast to "unmanaged code" which is compiled into native machine language that targets a specific system. The following diagram illustrates the compile-time and run time relationships of C# source code files, the base class libraries, assemblies, and the CLR.
Language interoperability is a key feature of the .NET Framework. Because the IL code produced by the C# compiler conforms to the Common Type Specification (CTS), IL code generated from C# can interact with code that was generated from the .NET versions of Visual Basic, Visual C++, Visual J#, or any of more than 20 other CTS-compliant languages. A single assembly may contain multiple modules written in different .NET languages, and the types can reference each other just as if they were written in the same language.
In addition to the run time services, the .NET Framework also includes an extensive library of over 4000 classes organized into namespaces that provide a wide variety of useful functionality for everything from file input and output to string manipulation to XML parsing, to Windows Forms controls. The typical C# application uses the .NET Framework class library extensively to handle common "plumbing" chores.
Extreme https://www.doczj.com/doc/3d15480229.html, 1.1Web Deployment Projects When ASP was first released, Web programming was more difficult because you needed IIS to serve your ASP pages. Later, https://www.doczj.com/doc/3d15480229.html, 2.0 and Visual Studio? 2005 made everything easier by introducing the Web site model of development. Instead of creating a new project inside Visual Studio, the Web site model lets you point to a directory and start writing pages and code. Furthermore, you can quickly test your site with the built-in https://www.doczj.com/doc/3d15480229.html, Development Server, which hosts https://www.doczj.com/doc/3d15480229.html, in a local process and obviates the need to install IIS to begin developing. The beauty of the Web site model is that you can develop your Web application without thinking about packaging and deployment. Need another class? Add a .cs file to the App_Code directory and start writing. Want to store localizable strings in a resource file? Add a .resx file to the App_GlobalResources directory and type in the strings. Everything just works; you don't have to think about the compilation and deployment aspect at all. When you are ready to deploy, you have several options. The simplest choice is to copy your files to a live server and let everything be compiled on-demand (as it was in your test environment). The second option is to use the aspnet_compiler.exe utility and precompile the application into a binary release, which leaves you nothing but a collection of assemblies, static content, and configuration files to push to the server. The third option is to again use aspnet_compiler.exe, but to create an updateable binary deployment where your .as*x files remain intact (and modifiable) and all of your code files are compiled into binary assemblies. This seems to cover every possible scenario, leaving the developer to focus simply on writing the Web application, with packaging and deployment decisions to be made later when the application is actually deployed. There was a fair amount of backlash against this model, however, especially from developers who were used to their Web projects being real projects, specified in real project files, that let you inject pre-and post-build functions, exclude files from the build process, move between debug and release builds with a command-line switch, and so on. In response, Microsoft quickly introduced the Web Application Project or WAP, initially released as an add-in to Visual Studio 2005, and now included in Visual Studio 2005 Service available for download from https://www.doczj.com/doc/3d15480229.html,/vstudio/support/vs2005sp1. WAP provides an alternative to the Web site model that is much closer to the Visual Studio .NET 2005 Web Project model. The new WAP model compiles all of the source code files during the build process and generates a single assembly in the local /bin directory for deployment. WAP also makes it much easier to incrementally adopt the new partial class codebehind model
Hydraulic machinery and pump Hydraulic machinery are machines and tools which use fluid power to do work. Heavy equipment is a common example. In this type of machine, high-pressure liquid - called hydraulic fluid - is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders. The fluid is controlled directly or automatically by control valves and distributed through hoses and tubes. The popularity of hydraulic machinery is due to the very large amount of power that can be transferred through small tubes and flexible hoses, and the high power density and wide array of actuators that can make use of this power. Hydraulic machinery is operated by the use of hydraulics, where a liquid is the powering medium. Pneumatics, on the other side, is based on the use of a gas as the medium for power transmission, generation and control. Hydraulic circuits For the hydraulic fluid to do work, it must flow to the actuator and or motors, then return to a reservoir. The fluid is then filtered and re-pumped. The path taken by hydraulic fluid is called a hydraulic circuit of which there are several types. Open center circuits use pumps which supply a
双吸离心泵毕业设计-开题报告
毕业设计(论文)开题报告 学生姓名：陈乐东学号：20121698 学院：机电工程学院 专业：热能动力工程 设计(论文)题目：800S26型双吸泵的设计 指导教师：杨辉 2016年2月15日
开题报告填写要求 1．开题报告（含“文献综述”）作为毕业设计（论文）答辩委员会对学生答辩资格审查的依据材料之一。此报告应在指导教师指导下，由学生在毕业设计（论文）工作前期内完成，经指导教师签署意见及所在专业审查后生效； 2．开题报告内容必须用黑墨水笔工整书写或按教务处统一设计的电子文档标准格式（可从教务处网页上下载）打印，禁止打印在其它纸上后剪贴，完成后应及时交给指导教师签署意见； 3．“文献综述”应按论文的格式成文，并直接书写（或打印）在本开题报告第一栏目内，学生写文献综述的参考文献应不少于15篇； 4．有关年月日等日期，按照如“2002年4月26日”方式填写。
1．结合毕业设计（论文）课题情况，根据所查阅的文献资料，每人撰写1500字左右的文献综述（包括研究进展，选题依据、目的、意义） 文献综述 800S26型双吸泵的型号意义是，入口直径为800mm，设计点扬程为26m的单极双吸水平中开式离心清水泵。要想了解此泵，首先要了解双吸离心泵。 双吸离心泵是从叶轮两面进水的双吸离心泵，因泵盖和泵体是采用水平接缝进行装配的，又称为水平中开式离心泵。与单级单吸离心泵相比，效率高、流量大、扬程较高。但体积大，比较笨重，一般用于固定作业。适用于丘陵、高原中等面积的灌区，也适用于工厂、矿山、城市给排水等方面。 S型单极双吸离心泵也被称为为中开式离心泵，供抽送清水或物理化学性质类似于水的其他液体之用。S系列单级双吸离心泵主要适用于自来水厂、空调循环用水、建筑供水、灌溉、排水泵站、电站、工业供水系统、消防系统、船舶工业等输送液体的场合。 S型中开泵与其他同类型泵相比较具有寿命长、效率高、结构合理，运行成本低、安装及维修方便等特点，是消防、空调、化工、水处理及其他行业的理想用泵。泵体设计压力为1.6MPa和2.0MPa。泵体的进出口法兰均位于下泵体，这样可以在不拆卸系统管路的情况下取出转子，维修方便。部分泵体采用双流道设计，以减少径向力，从而延长机封和轴承的寿命。叶轮叶轮的水力设计采用了最先进的 CFD 技术,因此提高了S泵的水力效率。对叶轮进行动平衡, 确保S泵的运行平稳。轴轴径较粗,轴承间距较短,从而减小了轴的挠度,延长了机械密封和轴承的寿命。轴套可以采用多种不同的材料,以防止轴被腐蚀和磨损,轴套可更换。磨损环泵体与叶轮间采用可更换的磨损环,防止泵体和叶轮的磨损,更换方便,维修费用低,同时保证运行间隙和较高的工作效率。既可以使用填料也可以使用机械密封,可以在不拆卸泵盖的情况下更换密封装置。轴承独特的轴承体设计使轴承可采用油脂或稀油润滑,轴承的设计寿命10万小时以上,也可使用双列推力轴承和封闭轴承。材料根据用户的实际需要,S型中开泵的材料可为铜、铸铁、球铁、316不锈钢、416;7锈钢、双向钢、哈氏合金、蒙耐合金,钛合金及20号合金等材料。 我国水泵技术的现状 1、我国泵产品图样的来源可分为联合设计、引进、自行开发等几种，引进的这些
毕业设计(论文)外文资料翻译 学院 专业 学生姓名 班级学号 外文出处 附件：1.外文资料翻译译文；2.外文原文 指导教师评价： 1．翻译内容与课题的结合度：□优□良□中□差2．翻译内容的准确、流畅：□优□良□中□差3．专业词汇翻译的准确性：□优□良□中□差4．翻译字符数是否符合规定要求：□符合□不符合 指导教师签名： 年月日
附件1：外文资料翻译译文 非常https://www.doczj.com/doc/3d15480229.html, 1.1Web 部署项目 当ASP 第一次发布时，Web 编程还比较困难，因为需要 IIS 来处理 ASP 页。后来，https://www.doczj.com/doc/3d15480229.html, 2.0 和 Visual Studio? 2005 通过引入网站开发模型使一切工作都变得容易了。借助该网站模型，您不必在 Visual Studio 中创建新项目，而是可以指向一个目录并开始编写网页和代码。此外，您还可以使用内置的 https://www.doczj.com/doc/3d15480229.html, Development Server 快速测试站点，https://www.doczj.com/doc/3d15480229.html, Development Server 将 https://www.doczj.com/doc/3d15480229.html, 寄宿在一个本地进程中，并消除了必须安装 IIS 才能进行开发这一先决条件。该网站模型的魅力在于您在开发 Web 应用程序时无需考虑打包和部署。需要其他类时怎么办？向 App_Code 目录添加一个 .cs 文件即可开始编写。希望将可本地化的字符串存储在资源文件中时怎么办？向 App_GlobalResources 目录添加一个 .resx 文件并键入字符串。一切都顺顺当当；您根本就不必考虑编译和部署方面的事情。 在准备进行部署时，您有多种可选方案。最简单的方案是将文件复制到主运行服务器并按要求编译每一个文件（和在测试环境中一样）。第二种方案是使用 aspnet_compiler.exe 实用工具将应用程序预编译为二进制版本，之后将只剩下要放到服务器上的一组程序集、静态内容和配置文件。第三种方案也使用 aspnet_compiler.exe，但要创建一个可更新的二进制部署，其中 .as*x 文件保持不变（并且可修改），而所有代码文件都编译为二进制程序集。 这似乎涵盖了每一种可能的情况，开发人员可以一心一意地编写 Web 应用程序，而在以后实际部署时再作打包和部署决定。不过，此模型也遭到了相当大的反对，特别是那些习惯了自己开发的 Web 项目是在实际项目文件中指定的实际项目的开发人员的反对，这些项目允许注入生成前和生成后函数、从生成过程排除文件以及使用命令行开关在调试和发布版本之间进行切换等操作。有鉴于此，Microsoft 迅速推出了 Web 应用程序项目（即 WAP），最初它是作为 Visual Studio 2005 的插件发布的，现在包含在 Visual Studio 2005 Service Pack 1 (SP1) 中，Visual Studio 2005 Service Pack 1 (SP1) 可从https://www.doczj.com/doc/3d15480229.html,/vstudio/support/vs2005sp1 下载。 WAP 可替代与 Visual Studio .NET 2005 Web 项目模型非常接近的网站模型。新的WAP 模型会在生成过程中编译所有源代码文件，并在本地的 /bin 目录中生成一个用于部署的程序集。WAP 还使得增量采用 https://www.doczj.com/doc/3d15480229.html, 2.0 引入的新的分部类代码隐藏模型变得更
利用神经网络预测轴向柱塞泵的性能 Mansour A Karkoub a, Osama E Gad a, Mahmoud G Rabie b a--就读于科威特的科威特大学工程与石油学院 b--就读于埃及开罗的军事科技大学 摘要 本文推导了应用于轴向柱塞泵（斜轴式）的神经网络模型。该模型采用的数据是由一个实验装置获得的。这个正在进行的研究的目的是降低柱塞泵在高压下工作时的能量损耗。然而，在最初我们要做一些研究来预测当前所设计的泵的响应。神经网络模型具有前反馈的结构，并在测验过程中使用Levenberg-Marquardt优化技术。该模型能够准确地预测柱塞泵的动态响应。 1、简介 可变排量轴向柱塞泵是在流体动力系统中经常要用到的重要设备，如液压动力供应控制和静液压传动驱动器的控制。本装置具有变量机制和功率-重量比特性，使其最适合于高功率电平的控制。所设计的这种轴向柱塞泵拥有可靠性和简便的特点，然而其最重要的特征是可以变量输出。 人们在轴向柱塞泵领域已经做了很多研究，但是本文将只论述一下少数几人所做的贡献。 Kaliafetis和Costopoulos[5]用调压器研究了轴向柱塞变量泵的静态和动态特性。所提出的模型的精确度依赖于制造商提供的动态运行曲线等数据。他们得出结论，运行条件对泵的动态行为是非常关键的，而泵的动态行为可以通过减小压力设定值进行改善。Harris等人[4]模拟和测量了轴向柱塞泵的缸体压力和进油流量脉动。Kiyoshi和Masakasu[7]研究了斜盘式变量输送的轴向柱塞泵在运行时刻的实验上和理论上的静态和动态特性。并提出了一种新的方法来预测泵在运行过程中的响应。也对研究泵特性的新方法的有效性进行了实验验证，实验中使用了一个有宽、短而深的凹槽的配流盘。Edge和Darling[2]研究了液压轴向柱塞泵的缸体压力和流量。这个得出的模型经过了实验检验。对于配流盘、缸体上设计的退刀槽和泵的流量脉动对泵特性的影响都进行了验证。 人们已证实了一种可替代的建模技术——神经网络（NN）能取得良好的效果，特别是对于高度非线性的系统。这种技术是模仿人脑获取信息的功能。Karkoub 和Elkamel[6]用神经网络模型预测了一个长方形的气压轴承的压力分布。所设计的这种模型在预测压力分布和承载能力方面比其他可用的工具更加精确。Gharbi 等人[3]利用神经网络预测了突破采油。其表现远远优于常见的回归模型或有限差分法。李等人[8]用神经网络模型NNS和鲍威尔优化技术对单链路和双链路的倒立摆进行了建模和控制。研究者们取得了理想的结果。Panda等人[9]应用NNS在普拉德霍湾油田对流体接触进行了建模。所得到的模型预测的目标油井中的流量分配比传统的以回归为基础的技术更准确。Aoyama等人[1]已经推导出一个神经网络模型来预测非最小相系统的响应。所开发出的的模型被应用于Van de Vuss反应器和连续搅拌式生物反应器，所得到的结果是令人满意的。 本文研究利用神经网络解决轴向柱塞泵（斜轴式）在一定的供油压力下的建模。本文首先会描述用于收集实验数据的实验装置，然后将会简要介绍神经网络建模程序。 2、实验装置
各种水泵英文翻译 abration resisting pump ,,,,, 耐磨泵； absorption pump ,,,,, 吸收泵； acid pump ,,,,, 耐酸泵； activated sludge pump ,,,,, 活性污泥泵 adjustable diaphragm pump ,,,,, 可调隔膜泵； adjustable discharge gear pump ,,,,, 齿轮比例泵； adsorption vacuum pump ,,,,, 吸附真空泵； agricultural spray pump ,,,,, 喷灌泵； agricultural spray pump for chemicals ,,,,, 农用喷药泵； air lift pump ,,,,, 气泡泵；曼木特泵；气举泵； air operated pump ,,,,, 压缩空气驱动泵； air-powered piston pump ,,,,, 风动活塞泵； air-pressure actuated slurry pump ,,,,, 气动泥浆泵； airtight screw pump ,,,,, 密闭式螺杆泵； all abronze pump ,,,,, 全青铜泵； all iron pump ,,,,, 铸铁泵； alloy pump ,,,,, 合金泵； alloy steel pump ,,,,, 合金钢泵； angle-type axial flow pump ,,,,, 半贯流式轴流泵；弯管轴流泵； angle-type axial piston pump ,,,,, 斜轴式轴向活塞泵； animal self-operated drinking water pump ,,,,, 饲槽自动泵；家畜自动饮水泵；annular casing pump ,,,,, 环壳泵； anti-roll pump ,,,,, 减摇泵； Archimedean screw pump ,,,,, 螺旋泵； armoured pump ,,,,, 铠装泵； articulated vane pump ,,,,, 铰链滑片泵； ash pump ,,,,, 灰渣泵； attached pump ,,,,, 附属泵； automatic trough pump ,,,,, 饲槽自动泵；家畜自动引水泵； automobile pump ,,,,, 汽车用泵； auxiliary pump ,,,,, 辅泵；辅助泵； auxiliary stripping pump ,,,,, 辅扫仓泵；辅清仓泵； aviation pump ,,,,, 航空用泵； axial double entry liquid ring pump ,,,,, 轴向双吸液环泵； axial flow ,,,,, 轴流泵； axial flow pump for water jet propulsion ,,,,, 喷水推进轴流泵； axial flow pump with adjustable pitch blades ,,,,, 可调式轴流泵； axial flow pump with blades adjustable in operation ,,,,, 全可调式轴流泵axial flow pump with blades adjustable when stationary ,,,,, 半可调式轴流泵；axial flow pump with variable pitch blades ,,,,, 全可调式轴流泵； axial flowpump with reversible blades ,,,,, 可逆叶片轴流泵； axial inlet pump ,,,,, 轴吸泵；
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附件1：外文资料翻译译文 1 液压传动概述 1.1 液压传动的发展概况 1.1.1 压传动的定义 一部完整的机器是由原动机部分、传动机构、控制部分及工作机部分组成。原动机有几种类型，例如电动机、内燃机等。工作机即完成该机器的工作任务的直接工作部分，如剪床的剪刀，车床的刀架、车刀、卡盘等。由于原动机的功率和转速比是被限制的，为了覆盖工作机较大范围的工作力和工作速度的变化，以及操作性能的要求，在原动机和工作机之间设置了传动机构，其作用是把原动机输出功率经过变换后传递给工作机。 传动机构通常分为电气传动、机械传动和流体传动三类机构。流体传动是通过液压、流体或气体来进行能量传递和控制的。但需要认识到实际上只有两种液压系统：液力传动和液压传动（包括液力和气体）。 液压传动和液力传动均是以液体作为工作介质来进行能量传递的传达方式。液力传动则主要是利用液体的动能来传递能量；而液压传动主要是利用液体的压力能来传递能量。由于液压传动有许多突出的优点，因此，它被广泛的应用于工业的每个分支。一些典型的运用像机械工程、建筑、海洋开发、交通运输、农业和航天航空 1.1.2 液压传动的发展概况 到18世纪中叶的工业革命，电能已经不能支持工业机器的传动需求。18世纪末液压传动被用于驱动液力设备，例如起重机、压力机、绞车、压榨机、液力千斤顶、修剪机械、和支承机械。在这些系统中，是一种由蒸汽机驱动液力的水泵，这种泵是通过压力将水通过管道传到工业机械来驱动各种机器的。这些早期的液力系统有着许多的不足，例如设计问题，由于设计已经发展为艺术而多过了科学。然而，直到19世纪电力成为新的有优势的技术。这样的结果液压传动并没有起到推动的作用。电力传动不久被发现在远距离传递上有良好的效果。在19世纪最后的10年里液压传动技术只有小小的发展。近代，1906年液压传动开始被重视，是当时用液
CENTRIFUGAL PUMP IN CHEMICALPRODUCTIONAPPLICATION Centrifugal pump in chemical production, this is most widely used because of its performance wide range (including flow, pressure head of media properties and ShiYing sexual), small volume, simple structure, easy operation, flow uniformity, low malfunction, long service life, CaoZuoFei are lower cost and prominent advantages. (1)centrifugal pump principle of work Centrifugal pump working principle is: centrifugal pump so can turn the water away is because only centrificating. Water pump before work, pump body and feed water full line must be cans in vacuum condition, when the impeller fast turns, leaf prompted water quickly spin, spin in the water under the action of the centrifugal force, pump impeller flew in from the water was thrown in the central part of the impeller, after forming vacuum area. Water in the water atmospheric pressure (or water pressure) under the action of water pipe pressure came through a tube. This cycle unceasingly, can achieve continuous pumped. In the centrifugal pump is worth mentioning: before initiating must to the pump housing filled with water, can start after, otherwise will cause, the vibration of the pump body, thus reduce heat pump, damage to (hereinafter referred to as "cavitation erosion") cause equipment accident! Centrifugal pump is a lot of more phyletic, classification methods common has the following kinds of kind: 1, press the impeller inhaled way points: single suction style centrifugal pump double suction type centrifugal pump. 2, press the impeller number points: single grade centrifugal pump mulfistage centrifugal pump. 3, according to the structure of impeller points: open impeller centrifugal pump impeller half open centrifugal pump closed impeller centrifugal pump. 4, according to work pressure points: low voltage centrifugal pump medium centrifugal pump high-pressure centrifugal pump. 5, according to pump shaft position points: horizontal centrifugal pump edge vertical centrifugal pump. (2) basic structure, centrifugal pumps
C# Programming for the Beginner Welcome to C# and the world of Windows, Internet and World-Wide-Web programming with Visual Studio and the .NET platform! This book is the second in our new .NET How to Program series, which presents various leading-edge computing technologies in the con- text of the .NET platform. C# is the next phase in the evolution of C and C++ and was developed expressly forMicrosoft’s .NET platform. C# provides the featu res that are most important to program-mers,suchasobject-orientedprogramming,strings,graphics,graphical-user-inte rface(GUI) components, exception handling, multithreading, multimedia (audio, images, ani-mation and video), file processing, prepackaged data structures, database processing,Internet and World-Wide-Web-based client/server networking and distributed computing.The language is appropriate for implementing Internet- and World-Wide-Web-based appli-cations that seamlessly integrate with PC-based applications. The .NET platform offers powerful capabilities for software development and deploy-ment, including independence from a specific language or platform. Rather than requiringdevelopers to learn a new programming language, programmers can contribute to the samesoftware project, but write code using any (or several) of the .NET languages (such as C#,Visual Basic .NET, Visual C++ .NET and others) with which they are most competent. Inaddition to providing language independence, .NET extends program portability byenabling .NET applications to reside on, and communicate across, multiple platforms—thus facilitating the delivery of Web services over the Internet. The .NET platform enablesWeb-based applications to be distributed to consumer-electronic devices, such as cellPrefaceXXXIXphones and personal digital assistants, as well as to desktop computers. The capabilities thatMicrosoft has incorporated into the .NET platform create a new software-development par-adigm that will increase
1.概述 (2) 2.工艺说明 (2) 2.1工艺介绍 (2) 2.2物料性质 (2) 2.3工作温度 (2) 2.4工作压力 (2) 3.机械设计 (3) 3.1材料选择 (3) 3.2结构设计 (3) 3.3设计参数计算 (4) 4.零部件的选型 (4) 4.1法兰的选型 (4) 4.2人孔的选型 (5) 4.3容器支座的选型 (5) 5.总结 (5) 参考文献 (6)
1.概述 离心泵是工业生产中应用最为广泛的液体输送机械。其突出特点是结构简单、体积小、流量均匀、调节控制方便、故障少、寿命长、适用范围广、购置费用和操作费用较低。 离心泵依靠旋转叶轮对液体的作用把原动机的机械能传递给液体。由于离心泵的作用液体从叶轮进口流向出口的过程中，其速度能和压力能都得到增加，被叶轮排出的液体经过压出室，大部分速度能转换成压力能，然后沿排出管路输送出去，这时，叶轮进口处因液体的排出而形成真空或低压，吸水池中的液体在液面压力（大气压）的作用下，被压入叶轮的进口，于是，旋转着的叶轮就连续不断地吸入和排出液体。 2.工艺说明 2.1工艺介绍 离心泵的基本构造是由六部分组成的，分别是：叶轮，泵体，泵轴，轴承，密封环，填料函。 2.2物料性质 传输介质是清水，正常的沸点和熔点是100℃、不具有腐蚀性和毒性 2.3工作温度 介质温度不高于80℃ 环境温度不高于40℃ 2.4工作压力
允许吸入管路压力0.3MPa，泵的最高使用压力1.6MPa 3.机械设计 3.1材料选择 根据工艺参数和介质特性来选择泵的系列和材料。 （1）根据介质特性决定选用哪种特性泵，如清水泵、耐腐蚀泵和杂质泵等。介质为剧毒、贵重或有放射性等不允许泄漏物质时，应考虑选用无泄漏泵（如屏蔽泵、磁力泵）或带有泄漏液收集和泄漏报警装置的双端面机械密封。如介质为液化等易发挥发液体应选择低汽蚀余量泵、如筒型泵。 （2）根据选择安装条件选择卧式泵、立式泵（含液下泵、管道泵）。（3）根据流量大小选用单吸泵、双吸泵，或小流量离心泵。 （4）根据扬程高低选用单级泵、多级泵，或高速离心泵等。 3.2结构设计 1、叶轮是离心泵的核心部分，它转速高输出力大，叶轮上的叶片又起到主要作用，叶轮在装配前要通过静平衡实验。叶轮上的内外表面要求光滑，以减少水流的摩擦损失。 2、泵体也称泵壳，它是水泵的主体。起到支撑固定作用，并与安装轴承的托架相连接。 3、泵轴的作用是借联轴器和电动机相连接，将电动机的转矩传给叶轮，所以它是传递机械能的主要部件。
中英文对照资料外文翻译文献附件1：外文资料翻译译文 旋转泵 旋转泵应用于不同的设计中，在流体动力系统中极其常用。今天最常用的旋转泵是外齿轮泵、内齿轮泵、摆线转子泵、滑动叶片泵和螺旋泵。每种类型的泵都有优点，适合于特定场合的应用 直齿齿轮泵，这种泵有两个啮合的齿轮在密封壳体内转动。第一个齿轮即主动轮的回转引起第二个齿轮即从动轮的回转。驱动轴通常连接到泵上面的齿轮上。 当泵首次启动时，齿轮的旋转迫使空气离开壳体进入排油管。这种泵内空气运动使泵吸入口处形成了真空，于是外部油箱的液体在大气压的作用下，由泵的入口进入，聚集在上下齿轮和泵壳体之间，齿轮连续的旋转使液体流出泵的出口。 直齿齿轮泵的压力的升高是由挤压啮合齿轮和腔体内的液体产生的。当齿轮脱开啮合时，腔内形成真空，使更多的液体被吸入泵内。直齿齿轮泵是定排量的元件，当轴转速不变时，输出流量恒定。只有一种方法即改变输入轴的转速，能调节这种直齿齿轮泵的排量。现代应用在流体动力系统的齿轮泵的压力可达3000psi。 图示为直齿齿轮泵的典型特性曲线。这些曲线表明了泵在不同速度下的流量和输入功率。当速度给定时，流量曲线接近于一条水平的直线。泵的流量随出口压力的升高而稍有降低，这是由于泵的出油口到吸油口的齿轮径向泄漏所增加而造成的。渗漏有时定义为泄漏，泵出口压力的增加也会使泄漏增加。表征泵的出口压力和流量之间关系曲线常叫做水头流量曲线或泵的HQ曲线；泵的输入功率和泵流量关系曲线叫做功率流量特性曲线或PQ曲线。 直齿齿轮泵的输入功率随输入速度和出口压力的增加而增加。随着齿轮泵速度的增加，流量（加仑/分）也增加。于是在出口压力为120psi，转速为200rpm时，输入功率是5马力。在转速为600rpm时，输入功率是13马力。纵坐标压力是120psi，