雕刻机毕业设计外文文献翻译
附录1外文翻译-原文部分
DXF File Identification with C# for CNC Engraving Machine System Huibin Yang, Juan Yan
Abstract
This paper researches the main technology of open CNC engraving machine,the DXF identification technology. Agraphic information extraction method is proposed. By this method,the graphic information in DXF file can be identified and transformed into bottom motion controller’s code. So the engraving machine can achieve trajectory tracking. Then the open CNC engraving machine system is developed with C#. At last, the method is validated on a three axes motion experiment platform. The result shows that this method can efficiently identify the graphic information including line, circle, arc etc. in DXF file and the CNC engraving machine can be controlled well.
Keywords
DXF, CNC Engraving Machine , GALIL,C#
1.Introduction
With the development of pattern recognition techniques, modern CNC engraving machine needn’t be programmed manually. By importing graphics file, the corresponding shape will be engraved by the machine immediately. The operating process of the machine is simplified enormously, and the rich programming knowledge is no longer need for operators. Among them, DXF identification is a key technology of CNC engraving machine. By reading and recognition of the DXF file, the machining track can be directly generated, so the motion control of the CNC engraving machine can be achieved.
2. Research Status
Researchers have done a lot of researches on how to contact CAD software to NC code. Omirou and Barouniproposed a series of machine codes, with which the advanced programming ability is integrated into the control of modern CNC milling machine system [1]. Kovacic and Brezocnik proposed the concept of which using the genetic algorithm to program the CNC machine based on the CAD model under manufacturing environment [2].But some problems are still existed in this kind of CNC programming (such as the artificial participation degree is higher and the efficiency is lower).
The research direction of Chinese researchers mainly includes two aspects. One is the theoretical study of DXF file and NC machining, the other is the application of DXF file reading. ZhaiRui and Zhang Liang proposed a program structure, which is used to read data information of DXF file and do some preprocess based on the cross platform open source library DXF Lib by the analysis of DXF file structure characteristic [3]. Huang Jieqiong and Yuan Qun wrote the interface program to read the stored parts graphic information in DXF file by use of the object-oriented secondary development tools, Object ARX and C++, in the research of stamping parts machining. The stamping parts geometric model is automatically created by the automatic generation algorithm of closed contour [4].
3. DXF File and Graphic Information Extraction
3.1. DXF File
DXF (Drawing Exchange File) is a representation of all information labeled data contained in the AutoCAD graphics file, and the ASCII or binary file format of AutoCAD file. It can be used as input/output interface and graphics file exchange between AutoCAD and other graphics applications [5].A complete DXF file is composed of six segments called SECTION. These segments were HEADER,CLASSES, TABLES, BLOCKS, ENTITIES and file ending character (group code is 0,group value is EOF)
3.2. Graphic Information Extraction Method
In order to extract useful information of the graphic, many parts in the file can be ignored. The corresponding geometric description can be completed as long as the sections of TABLES,BLOCK, ENTITIES are obtained. Each graphic element in the DXF file are stored with a fixed format, so it is convenient for data exchange, and also called its readability. The characteristics of each individual graphic element in DXF file is described by the parameter (group) consisted by paired group code and group value. Therefore, according to the target of open CNC engraving machine, it is enough to describe the target geometry contour by reading the ENTITIES section in DXF files only. The particular identification process is: First search the DXF file until the “ENTITLES” is found, then build a graphic element object. Then search the graphic element type (LINE, CIRCLE, ARC),and search the corresponding value followed by
the group code. For example, if the program has found the ENTITLES section and confirm the first graphic element is LINE (The program found “LINE” after “ENTITLES”). Then it will search the group code which represents the parameters of the line. The number at the next line after the group code is the value of the parameter.(e.g. The number at the next line after “10” represent the X value of start point of this line, and “20” for Y value of start point,“11” for X value of end point,“21” for Y value of end point, etc.). Table 1 shows an example of an ENTITIES section. Table 1 shows an example of an ENTITIES section.
By getting these parameters and values, system then “sees” the graph and “knows” the specific parameters of the graph which is drew by AutoCAD. Figure 1 is the flow diagram of extraction of graphic information. Table 1 shows an example of an ENTITIES section.
3.3. C# Realization of Graphic Information Extraction
In order to store the graph data, the convenient method is to store numeric variables by using array, and it is also very convenient for call and assignment operation. First define a 2D array:
s[i,j] (i <= 100,j <= 20),define a 100 lines and 20 lows array at initialization, in which, every line i stores a graphic element, every element j in a line stands for the value after the group code. The format and meaning are shown in Table 2
Then, the graphic element storage state is s[i,0],s[i,1],???,s[i,15] (I = 0,1,2,???).The advantage of this design is: For each graphic element, all the geometric elements associated with the trajectory can be stored in an array variable space which has a fixed serial number. It is convenient and not easy to make mistakes in the calculation or logical judgment. But to any entire graphics trajectory, the number of lines or curves is not consistent, so it is important to apply for enough variable memory space to adapt to different requirements of graphics trajectory. Part of the C# program of reading arc graphic element in DXF are as follows：
do
{
Line = mysr. ReadLine ();
if (Line == “ENTITIES”)
{
……
if (Line == “10”)
{
Line = mysr.ReadLine();
string m;
m = Line;
double n;
n = Convert.ToDouble(m);
s[i,j] = n;
j++;
}
……
} while (Line! = null)
4. Graphics Trajectory Generation
To open CNC engraving machine,the key point is how to convert the graphic element information in DXF file into motion controller code, so as to control the machine’s motion according to the machining trajectory.
4.1. DXF Analysis Principle
The so-called DXF analysis is the standardization of each graphic element which has been read in order to according with the standard instructions of motion controller. Considering the basic type of graphic element is line, circle or arc, the standardization requirements of different graphic element type are different. The specific principles are as follows:
1) LINE
Line has only start and end point coordinate. the actual useful memory space is s[i,0],s[i,1],…,s[i,6],other parts are all zero.
2) ARC
As the format of arc in the DXF is include the center coordinates value, radius, start angle and
end angle. So the center coordinates value, radius, start angle and end angle can be recognized and stored in s[i,7],s[i,8],…,s[i,12] .But for the GALIL DMC2143 motion controller which is used in the open CNC engraving machine,the arc instruction requires start and end point coordinate and rotation angle of the arc. So, the analysis of arc includes two aspects: a) Calculate the start and end point coordinate. b) Calculate the rotation angle and store in s [i,15].
3) CIRCLE
Because the rotation angle of circle is 360?,it can be set as a fixed value. For the sake of convenience, the starting position of circle is set to the left or right quadrantal points.
4.2. DXF Analysis Method
According to 3.1, the difficulty of graphic element analysis is arc. Although the information in DXF file can confirm geometry feature, for the track sequencing, the start and end point coordinates are needed; and for the motion controller programs, it also need to change the format for direct connection. By four elements of center, radius, start angle and end angle as well as simple trigonometric function calculation, the start and end point position as well as the rotation angle of the arc can be determined. For example, if center of the arc is o(x0,y0),radius is r, start angle is θ (0 < θ < 90?) and end angle is δ (0 < θ < 90?),according to the parametric equation of the circle, the start point a(x1,y1),end point b(x2,y2),and rotation angle ε can be calculated using Equation (1) to Equation (3):
5. Development of Open CNC Engraving Machine System
The hardware of the open CNC engraving machine system includes a motion controller and an upper computer (PC). The real-time control of the CNC engraving machine body is done by the motion controller. The main task of the motion controller is servo motor control and IO logic control. The PC runs The DXF analysis algorithm, Human-Machine Interface (HMI) and sends the motion control instructions got from the DXF analysis algorithm to the motion controller, so the engraving machine can be controlled. The software of the system includes PC program and motion controller program.
5.1. PC Program
The PC program includes HMI and DXF analysis program running in the background. DXF analysis program are mainly programmed based on DXF analysis principles and methods on 3.
5.2. Program Design of Motion Controller
In this design, the subprograms of linear and circular interpolation are programmed in GALIL motion controller. According to the results of DXF analysis in PC, call different subprogram in proper order and assign variable, the continuous tracking trajectory can be realized. The linear interpolation program of GALIL motion controller is as follows:
#LINEAR
MT 2,2
VMAB
VS 5000
V A 100000
VD 100000
VP X,Y
VE
BGS
EN
6. Test Running Result
By C#, the authors first finished the DXF file identification as well as the extraction and storage of graphic element information. The graphic element ordering operations were also achieved. At last,the graphics trajectories were generated by calling the bottom GALIL software instructions and achieved motion tacking. The test was carried out on a three axes motion experiment platform, the carving cutter was replaced with pen. Pen was fixed on the experiment platform. The test used a trajectory graph drawn by AutoCAD. The final result shows that the developed open CNC engraving machine system can accurately complete the identification of DXF file, and the walk path is consistent with the CAD file.
References
[1] Omirou Sotiris,L. and Barouni Antigoni,K. (2005) Integration of New Programming Capabilities into a CNC Milling
System. Robotics and Computer-Integrated Manufacturing,21,518-527. https://www.360docs.net/doc/0911075595.html,/10.1016/j.rcim.2004.10.002
[2] Kovacic,M.,Brezocnik,M.,Pahole,I.,Balic,J. and Kecelj,B. (2005) Evolutionary Programming of CNC Machines.
Journal of Materials Processing Technology,164-165,1379-1387. https://www.360docs.net/doc/0911075595.html,/10.1016/j.jmatprotec.2005.02.047
[3] Zhai,R. and Zhang,L. (2011) Reading Frame Design Based on the DXF File Format. Fujian Computer,4,107-109.
[4] Huang,J.Q. and Yuan,Q. (2012) Automatic Input and Identification for Stamping Graph Based on AutoCAD. Machinery Design & Manufacture,2,82-84.
[5] Bai,X.C. and Chen,Y.M. (2010) Automatic Programming of Bridge Cutting Machine Based on the DXF File. Equipment Manufacturing Technology,2,110-112.
附录2外文翻译-中文部分
利用C#识别DXF文件的数控雕刻机系统
Huibin Yang, Juan Yan
摘要
本文研究开放式数控雕刻机的关键技术，即DXF识别技术。图形信息提取方法被提出。通过这种方法，在DXF文件中的图形信息可以被识别和转换为运动控制器底部的代码。因此，雕刻机可以实现轨迹跟踪。然后利用C#对放数控雕刻机系统进行开发，最后在一个三轴运动的实验平台上对这个方法进行验证。结果表明该方法可以有效地识别DXF 文件中的线、圆、弧等图形信息，并且数控雕刻机可以被控制得很好。
关键字：DXF；数控雕刻机；GALIL；C#
1 介绍
随着模式识别技术的发展，现代数控雕刻机不必手动编程。通过导入图形文件，相应的形状就会被雕刻机立即雕刻出来.极大的简化了雕刻机的操作过程，使得操作者不再需要丰富的编程知识。其中，DXF识别是数控雕刻机的关键技术。通过阅读和识别DXF文件，可以直接生成加工轨迹,实现对数控雕刻机的运动控制。
2 研究现状
研究人员已经做了大量研究如何将CAD软件与NC代码联系起来。Omirou和Barouni 提出一系列机器代码，通过先进的编程能力集成到现代数控铣床的控制系统中。Kovacic 和Brezocnik提出运用遗传算法去给基于CAD模型在制造环境下的数控机床编程的理论,但是用这种数控编程的方法也存在很多的问题（例如人工参与程度高但效率低）。
中国研究人员的研究方向主要包括两个方面，一个是DXF文件和数控加工的理论研究，另一个是读取DXF文件的应用程序。翟睿和张良提出一个用于读取DXF文件的数据信息和做一些基于跨平台开源库DXF的DXF文件结构特点分析的预处理的程序结构。黄洁琼和元群编写使用面向对象的二次开发工具来读取存储部分图形信息的DXF文件的接口程序，以ARX和C++为对象来研究冲压件的加工。冲压件的几何模型运用封闭轮廓的自动生成算法来自动创建。
3 DXF文件和图形信息提取
3.1 DXF文件
DXF(图纸交换文件)表示所有的被标记的信息包含在AutoCAD的图形文件和ASCII 或二进制格式文件中，它可以用作输入/输出接口和图形文件在AutoCAD和其他图形应用程序之间转换。一个完整的DXF文件由六个被称作SECTION的段组成，这六段分HEADER，CLASSES，TABLES，BLOCKS，ENTITIES和文件结束字符（组代码为0，组值为EOF）。DXF文件每一段的结构和含义如图1所示。
图1 DXF 文件结构
3.2 图形信息提取方法
为了提取图形中的有用信息，在文件中的许多地方可以忽略。只要获得了表、块、实体的部分就可以做出对应的几何描述。每个在DXF 文件中的图形元素都被存储为一个固定的格式，所以它的数据交换非常的方便，这也被称为它的可读性。每个在DXF 文件中的图形元素的特征用配对组代码和组值等参数来描述。因此，根据开放式数控雕刻机锁定目标，它足以通过读取DXF 文件中的实体部分来描述目标的几何轮廓。其特定的识别过程是：首先搜索DXF 文件，直到找到“ENTITLES ”，然后构建一个图形元素对象。然后搜索图形元素类型(线、圆、弧)和紧随其后的组织代码的值。例如，如果程序发现ENTITLES 部分并确认第一个图形元素是LINE (程序发现“LINE ”在“ENTITLES ”之后)。然后它将搜索组代码代表的参数。组代码后下一行的数字就是参数的值。(如：下一行的数字“10”代表这一行的起始点的X 值，“20”代表起始点的Y 值，“11”代表这一行终点的X 值，“21”代表这一行终点的Y 值等)。表1为ENTITIES 部分的一个例子。
通过这些参数和值，系统就能 “看到”图形并“知道”所画的AutoCAD 图的具体参数。
包括所有应用程序定义的类信息。
大部分信息包含没有价值非CAD
应用程序。
记录在AutoCAD
系统中所有的标题变量的、当前值和当前状态。的大部分信息中包含没有价值的非
CAD 应用程序。
记录块名称、当前层的名字、块类型、块插
入基点和所有已经定义的块中的成员
表1 ENTITIES部分举例
DXF文件的部分解释
ENTITIES 段名称
0 组代码
LINE 图形元素类型
…
10
50.0 起始点X的值
20
100.0 起始点Y的值
30
0.0 起始点Z的值
11
350.0 终点X的值
21
500.0 终点Y的值
31
0.0 终点Z的值
ENDSEC 段结束符
3.3 C#实现图形信息提取
为了存储图形数据，较为方便的方法是使用数组来存储数字变量，也便于调用和赋值操作。首先定义一个二维数组：
s[i,j] (i <= 100,j <= 20)，定义一个100行和20个低点的初始化数组，每一行的i存储一个图形元素，在每一行的元素j代表组代码的值。格式各意义如表2。
然后，图形元素存储状态是s[i,0],s[i,1],???,s[i,15] (I = 0,1,2,???)。
这种设计的优点是：对于每一个图形元素，所有几何元素与轨迹可以存储在一个有固定的序列号的数组变量空间。在计算或逻辑判断时既方便又不容易犯错误。但对于整个图形轨迹,直线或曲线的数量并不一致，所以重要的是要有足够的变量内存空间来适应不同图形轨迹的需求。
部分阅读DXF文件中的图形元素的C#程如：
do
{
Line = mysr. ReadLine ();
if (Line == “ENTITIES”)
{
……
if (Line == “10”)
{
Line = mysr.ReadLine();
string m;
m = Line;
double n;
n = Convert.ToDouble(m);
s[i,j] = n;
j++;
}
……
} while (Line! = null)
表2 数据存储格式表
数组变量的位置数据的含义
[i, 0] 属性标志：1代表线，2代表圆，3代表弧
[i, 1] 起点的X轴坐标值
[i, 2] 起点的Y轴坐标值
[i, 3] 起点的Z轴坐标值
[i, 4] 终点的X轴坐标值
[i, 5] 终点的Y轴坐标值
[i, 6] 终点的Z轴坐标值
[i, 7] 一个圆或弧的中心的X轴坐标值
[i, 8] 一个圆或弧的中心的Y轴坐标值
[i, 9] 一个圆或弧的中心的Z轴坐标值
[i, 10] 一个圆或弧的半径值
[i, 11] 弧的起始角
[i, 12] 弧的终点角
[i, 13] 后续数据识别序号的排序过程
[i, 14] 给后续操作
[i, 15] 给后续操作
4 图形轨迹生成
要使数控雕刻机运转起来,关键是如何把DXF文件中的图形元素信息转化为运动控制器代码,以便根据运动轨迹来控制机器的运动。
4.1 DXF分析原理
所谓的DXF分析就是把每个已阅读的图形元素标准化为符合标准的运动控制器的指令。考虑图形元素的基本类型是线,圆形和弧形,不同类型的图形元素的标准化是不同的。具体原则如下:
1) 线
线只有开始和结束点坐标.实际有用的内存空间s[i,0],s[i,1],…,s[i,6],其他部分都是零。
2)弧
在DXF中弧的格式包括中心坐标的值,半径,开始角度和结束角度。中心坐标的值,半径,起始角度和结束角可以识别和存储在s[i,7],s[i,8],…,s[i,12]中。但对于用于开放式数控雕刻机的GALIL DMC2143运动控制器,弧指令需要开始和结束点的坐标和弧的旋转角度.所以弧的分析包括两个方面:1)计算开始和结束点坐标。2)计算旋转角度并存储在s [i,15]中。
3) 循环
因为圆的旋转角是360?,它可以设置为一个固定值.为了方便,循环的起始位置设为左边或者右边的象限点。
4.2 DXF分析方法
根据3.1知,图形元素分析最困难的是弧。尽管DXF文件中的信息可以确定几何特性,跟踪测序,获得需要的开始和结束点的坐标和运动控制器程序,但需要改变格式来直接连接。中心、半径、开始角度和结束角度这四种元素可以利用简单的三角函数来计算,开始和结束点的位置以及弧的旋转角度就可以确定。例如：如果弧中心是o(x0,y0),半径为r,开始角是θ(0 <θ< 90?)和结束角是δ(0 <θ< 90?),根据圆的参数方程,起点a(x1,y1),终点b(x2,y2),和旋转角ε可以使用方程(1)到方程(3)来计算：
5 建立开放式数控雕刻机系统
开放式数控雕刻机系统的硬件包括一个运动控制器和一个上位机。数控雕刻机的实时动作控制是由运动控制器来完成。运动控制器的主要任务是伺服电机控制和IO逻辑控制。电脑运行DXF分析算法,人机界面发送从DXF分析算法得到的运动指令到运动控制器,这样雕刻机就可以被控制。系统的软件包括电脑程序和运动控制器程序。
5.1 电脑程序
电脑程序包括人机界面和在后台运行的DXF分析程序。DXF分析程序的编写主要是基于DXF分析原则和第三节的方法。
5.2 运动控制器的程序设计
在这个设计中,线性和环形插值的子程序在GALIL运动控制器中编。根据在电脑中的DXF分析结果,把不同的子程序按正确顺序排列和赋值变量,实现连续的跟踪轨迹。GALIL运动控制器的线性插值程序如下:
#LINEAR
MT 2,2
VMAB
VS 5000
V A 100000
VD 100000
VP X,Y
VE
BGS EN
6 测试运行结果
通过C#,操作者首先完成了DXF文件识别以及图形元素信息的提取和存储。也实现了图形元素排序操作。最后,图形轨迹通过调用底部GALIL软件指令生成图形轨迹和实现运
动。这个测试采用三轴运动的实验平台进行,雕刻刀具换成了钢笔，笔固定在实验平台，测试使用AutoCAD的轨迹图绘制。最终结果表明,发展开放式数控雕刻机系统可以准确地完成DXF文件的识别,它的行走路径与CAD文件是一致的。
参考文献
[1]Omirou Sotiris,L. and Barouni Antigoni,K. (2005) Integration of New Programming Capabilities into a CNC Milling
System. Robotics and Computer-Integrated Manufacturing,21,518-527.
https://www.360docs.net/doc/0911075595.html,/10.1016/j.rcim.2004.10.002
[2]Kovacic, M., Brezocnik, M., Pahole, I., Balic, J. and Kecelj,B. (2005) Evolutionary Programming of CNC Machines.
Journal of Materials Processing Technology,164-165,1379-1387.
https://www.360docs.net/doc/0911075595.html,/10.1016/j.jmatprotec.2005.02.047
[3]Zhai, R. and Zhang,L. (2011) Reading Frame Design Based on the DXF File Format. Fujian Computer,4,107-109.
[4]Huang, J. Q. and Yuan,Q. (2012) Automatic Input and Identification for Stamping Graph Based on AutoCAD. Machinery Design & Manufacture,2,82-84.
[5]Bai, X. C. and Chen,Y.M. (2010) Automatic Programming of Bridge Cutting Machine Based on the DXF File. Equipment Manufacturing Technology,2,110-112.
机械专业毕业论文外文翻译
附录一英文科技文献翻译 英文原文： Experimental investigation of laser surface textured parallel thrust bearings Performance enhancements by laser surface texturing (LST) of parallel-thrust bearings is experimentally investigated. Test results are compared with a theoretical model and good correlation is found over the relevant operating conditions. A compari- son of the performance of unidirectional and bi-directional partial-LST bearings with that of a baseline, untextured bearing is presented showing the bene?ts of LST in terms of increased clearance and reduced friction. KEY WORDS: ?uid ?lm bearings, slider bearings, surface texturing 1. Introduction The classical theory of hydrodynamic lubrication yields linear (Couette) velocity distribution with zero pressure gradients between smooth parallel surfaces under steady-state sliding. This results in an unstable hydrodynamic ?lm that would collapse under any external force acting normal to the surfaces. However, experience shows that stable lubricating ?lms can develop between parallel sliding surfaces, generally because of some mechanism that relaxes one or more of the assumptions of the classical theory. A stable ?uid ?lm with su?cient load-carrying capacity in parallel sliding surfaces can be obtained, for example, with macro or micro surface structure of di?erent types. These include waviness [1] and protruding microasperities [2–4]. A good literature review on the subject can be found in Ref. [5]. More recently, laser surface texturing (LST) [6–8], as well as inlet roughening by longitudinal or transverse grooves [9] were suggested to provide load capacity in parallel sliding. The inlet roughness concept of Tonder [9] is based on ??e?ective clearance‘‘ reduction in the sliding direction and in this respect it is identical to the par- tial-LST concept described in ref. [10] for generating hydrostatic e?ect in high-pressure mechanical seals. Very recently Wang et al. [11] demonstrated experimentally a doubling of the load-carrying capacity for the surface- texture design by reactive ion etching of SiC
毕业设计外文翻译资料
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
机械类毕业设计外文翻译
本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And
Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices
毕业设计外文翻译附原文
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
毕业设计外文翻译-中文版
本科生毕业设计（论文）外文科技文献译文 译文题目(外文题目)学院(系)Socket网络编程的设计与实现A Design and Implementation of Active Network Socket Programming 机械与能源工程学院 专学业 号 机械设计制造及其自动化 071895 学生姓名李杰林 日期2012年5月27日指导教师签名日期
摘要：编程节点和活跃网络的概念将可编程性引入到通信网络中，并且代码和数据可以在发送过程中进行修改。最近，多个研究小组已经设计和实现了自己的设计平台。每个设计都有其自己的优点和缺点，但是在不同平台之间都存在着互操作性问题。因此，我们引入一个类似网络socket编程的概念。我们建立一组针对应用程序进行编程的简单接口，这组被称为活跃网络Socket编程（ANSP）的接口，将在所有执行环境下工作。因此，ANSP 提供一个类似于“一次性编写，无限制运行”的开放编程模型，它可以工作在所有的可执行环境下。它解决了活跃网络中的异构性，当应用程序需要访问异构网络内的所有地区，在临界点部署特殊服务或监视整个网络的性能时显得相当重要。我们的方案是在现有的环境中，所有应用程序可以很容易地安装上一个薄薄的透明层而不是引入一个新的平台。 关键词：活跃网络；应用程序编程接口；活跃网络socket编程
1 导言 1990年，为了在互联网上引入新的网络协议，克拉克和藤农豪斯[1]提出了一种新的设 计框架。自公布这一标志性文件，活跃网络设计框架[2，3，10]已经慢慢在20世纪90 年代末成形。活跃网络允许程序代码和数据可以同时在互联网上提供积极的网络范式，此外，他们可以在传送到目的地的过程中得到执行和修改。ABone作为一个全球性的骨干网络，开 始进行活跃网络实验。除执行平台的不成熟，商业上活跃网络在互联网上的部署也成为主要障碍。例如，一个供应商可能不乐意让网络路由器运行一些可能影响其预期路由性能的未知程序，。因此，作为替代提出了允许活跃网络在互联网上运作的概念，如欧洲研究课题组提出的应用层活跃网络（ALAN）项目[4]。 在ALAN项目中，活跃服务器系统位于网络的不同地址，并且这些应用程序都可以运行在活跃系统的网络应用层上。另一个潜在的方法是网络服务提供商提供更优质的活跃网络服务类。这个服务类应该提供最优质的服务质量（QOS），并允许路由器对计算机的访问。通过这种方法，网络服务提供商可以创建一个新的收入来源。 对活跃网络的研究已取得稳步进展。由于活跃网络在互联网上推出了可编程性，相应 地应建立供应用程序工作的可执行平台。这些操作系统平台执行环境（EES），其中一些已 被创建，例如，活跃信号协议（ASP）[12]和活跃网络传输系统（ANTS）[11]。因此，不 同的应用程序可以实现对活跃网络概念的测试。 在这些EES 环境下，已经开展了一系列验证活跃网络概念的实验，例如，移动网络[5]，网页代理[6]，多播路由器[7]。活跃网络引进了很多在网络上兼有灵活性和可扩展性的方案。几个研究小组已经提出了各种可通过路由器进行网络计算的可执行环境。他们的成果和现有基础设施的潜在好处正在被评估[8，9]。不幸的是，他们很少关心互操作性问题，活跃网络由多个执行环境组成，例如，在ABone 中存在三个EES，专为一个EES编写的应用程序不能在其他平台上运行。这就出现了一种资源划分为不同运行环境的问题。此外，总是有一些关键的网络应用需要跨环境运行，如信息收集和关键点部署监测网络的服务。 在本文中，被称为活跃网络Socket编程（ANSP）的框架模型，可以在所有EES下运行。它提供了以下主要目标： ??通过单一编程接口编写应用程序。 由于ANSP提供的编程接口，使得EES的设计与ANSP 独立。这使得未来执行环境的发展和提高更加透明。
机械类毕业设计外文文献翻译
沈阳工业大学工程学院 毕业设计（论文）外文翻译 毕业设计（论文）题目：工具盒盖注塑模具设计 外文题目：Friction , Lubrication of Bearing 译文题目：轴承的摩擦与润滑 系（部）：机械系 专业班级：机械设计制造及其自动化0801 学生姓名：王宝帅 指导教师：魏晓波 2010年10 月15 日
外文文献原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction. The friction caused by the wedging action of surface irregularities can be overcome
毕业设计_英语专业论文外文翻译
1. Introduction America is one of the countries that speak English. Because of the special North American culture, developing history and the social environment, American English has formed its certain unique forms and the meaning. Then it turned into American English that has the special features of the United States. American English which sometimes also called United English or U.S English is the form of the English language that used widely in the United States .As the rapid development of American economy, and its steady position and strong power in the world, American English has become more and more widely used. As in 2005, more than two-thirds of English native speakers use various forms of American English. The philologists of the United States had divided the English of the United States into four major types: “America n creating”; “Old words given the new meaning”; “Words that eliminated by English”;“The phonetic foreign phrases and the languages that are not from the English immigrates”[1]. Compared to the other languages, American English is much simple on word spelling, usage and grammar, and it is one of the reasons that American English is so popular in the world. The thesis analyzes the differences between American English and British English. With the main part, it deals with the development of American English, its peculiarities compared to that of British English, its causes and tendency. 2. Analyses the Differences As we English learners, when we learning English in our junior or senior school, we already came across some words that have different spellings, different pronunciations or different expressions, which can be represented by following contrasted words: spellings in "color" vs. "colour"; pronunciations in "sec-re-ta-ry" vs. "sec-re-try";
毕业设计外文翻译
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.360docs.net/doc/0911075595.html,，niuzhiguo@https://www.360docs.net/doc/0911075595.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.360docs.net/doc/0911075595.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
毕业设计外文翻译原文
编号： 毕业设计(论文)外文翻译 （原文） 院（系）：应用科技学院 专业：机械设计制造及其自动化 学生姓名：邓瑜 学号：0501120501 指导教师单位：应用科技学院 姓名：黄小能 职称： 2009年 5 月20 日
The Injection Molding The Introduction of Molds The mold is at the core of a plastic manufacturing process because its cavity gives a part its shape. This makes the mold at least as critical-and many cases more so-for the quality of the end product as, for example, the plasticiting unit or other components of the processing equipment. Mold Material Depending on the processing parameters for the various processing methods as well as the length of the production run, the number of finished products to be produced, molds for plastics processing must satisfy a great variety of requirements. It is therefore not surprising that molds can be made from a very broad spectrum of materials, including-from a technical standpoint-such exotic materials as paper matched and plaster. However, because most processes require high pressures, often combined with high temperatures, metals still represent by far the most important material group, with steel being the predominant metal. It is interesting in this regard that, in many cases, the selection of the mold material is not only a question of material properties and an optimum price-to-performance ratio but also that the methods used to produce the mold, and thus the entire design, can be influenced. A typical example can be seen in the choice between cast metal molds, with their very different cooling systems, compared to machined molds. In addition, the production technique can also have an effect; for instance, it is often reported that, for the sake of simplicity, a prototype mold is frequently machined from solid stock with the aid of the latest technology such as computer-aided (CAD) and computer-integrated manufacturing (CIM). In contrast to the previously used methods based on the use of patterns, the use of CAD and CAM often represents the more economical solution today, not only because this production capability is available pin-house but also because with any other technique an order would have to be placed with an outside supplier. Overall, although high-grade materials are often used, as a rule standard materials are used in mold making. New, state-of-the art (high-performance) materials, such as ceramics, for instance, are almost completely absent. This may be related to the fact that their desirable characteristics, such as constant properties up to very high temperatures, are not required on molds, whereas their negative characteristics, e. g. low tensile strength and poor thermal conductivity, have a clearly related to ceramics, such as sintered material, is found in mild making only to a limited degree. This refers less to the modern materials and components
抛光瓷砖毕业设计外文文献翻译
毕业设计外文资料翻译 题目POLISHING OF CERAMIC TILES 抛光瓷砖 学院材料科学与工程 专业复合材料与工程 班级 学生 学号 指导教师 二〇一二年三月二十八日
MATERIALS AND MANUFACTURING PROCESSES, 17(3), 401–413 (2002) POLISHING OF CERAMIC TILES C. Y. Wang,* X. Wei, and H. Yuan Institute of Manufacturing Technology, Guangdong University ofTechnology, Guangzhou 510090, P.R. China ABSTRACT Grinding and polishing are important steps in the production of decorative vitreous ceramic tiles. Different combinations of finishing wheels and polishing wheels are tested to optimize their selection. The results show that the surface glossiness depends not only on the surface quality before machining, but also on the characteristics of the ceramic tiles as well as the performance of grinding and polishing wheels. The performance of the polishing wheel is the key for a good final surface quality. The surface glossiness after finishing must be above 208 in order to get higher polishing quality because finishing will limit the maximum surface glossiness by polishing. The optimized combination of grinding and polishing wheels for all the steps will achieve shorter machining times and better surface quality. No obvious relationships are found between the hardness of ceramic tiles and surface quality or the wear of grinding wheels; therefore, the hardness of the ceramic tile cannot be used for evaluating its machinability. Key Words: Ceramic tiles; Grinding wheel; Polishing wheel
机械毕业设计外文翻译---装载机发展概况
外文资料翻译 学生姓名： 专业班级：机械设计制造及其自动化04级2班指导教师： 2008年6月
装载机发展概况 Abstract This paper have discussed s.s. ZL-50 type fork-lift truck mainly overall fictitious prototype design as well as some kinds of typical schoolwork operating modes imitate and emulate , include equipment and the overall parts needed build mould. In this design course, have applied ADAMS software and the software of PRO/ENGINEER. ADAMS software is used in the emulation of some kinds of schoolwork operating modes, and the software of PRO/ENGINEER is used to build mould mainly. Through the simulated emulation for some kinds of overall schoolwork operating modes, can see relatively distinctly the overall possible condition in actual schoolwork course that met , can in time modify , have reduced actual design time , have raised production efficiency. The innovation of this design Zhi is in in, imitate and have emulated fork-lift truck the 3 kinds of typical schoolwork operating mode in actual schoolwork, is effect again have imitated in actual schoolwork the hydraulic impact of use, so when being helpful to solve actual loading, the actual problem of meeting the stock that is hard to uninstall can so raise production efficiency. Key words: Fork-lift truck 、fictitious prototype , build mould, emulation, optimization、production efficiency Loader Development China's modern 20 wheel loaders began in the mid-1960s of the Z435. The aircraft as a whole rack, rear axle steering. After years of hard work, the attraction was the world's most advanced technology wheel loader on the basis of the successful development of the power of 162 KW of shovel-fit wheel loaders, stereotypes for Z450 (later ZL50), and in 1971 December 18, formally appraised by experts. Thus the birth of China's first articulated wheel loader, thus creating our industry loader formation and development history. Z450-type loader with hydraulic mechanical transmission, power shift, Shuangqiaoshan drive, hydraulic manipulation, articulated power steering, gas oil Afterburner brake wheel loaders, and other modern, the basic structure of the world's advanced level for the time . Basically represent the first generation of wheeled loading the basic structure. The aircraft in the overall performance of dynamic, and insertion force a rise of power and flexibility, manipulation of light, the higher operating efficiency of a series of advantages. 1978, Heavenly Creations by the Department in accordance with the requirements of machinery, worked out to LIUGONG Z450-based type of wheel loaders series of standards. The development of standards, with reservations Z