2009级机自专业英语试题a卷

重庆大学2009级机自《专业外语》课程试卷
2011 ~ 2012 学年 第 1 学期 开课学院： 机械工程学院 课程号：11007420
考试日期： 2011-12- 11
考试方式： 考试时间： 120 分钟
一、 翻译单句（5分/每小题，共40分）
1. It generally is not possible to realize the full potential of a new material unless the product is redesigned to exploit both the properties and the manufacturing characteristics of the material.
2. the temperature rise in a workpiece resulting from machining operations is a function of
the work done and of the specific heat of the workpiece material.
3. There are two problems with the process (laser-assisted machining). There is a physical problem initially of establishing the cutting parameters (laser power and focus, cutting speeds and feeds, etc.) and the psychological problem of convincing people it works well and has many advantages.
4. Excitation forces caused, say , by changes in flow of fluids or out-of-balance rotating or reciprocating parts, can often be reduced by attention to design and manufacturing details.
5. The problem of wear arises wherever there are load and motion between surfaces, and is therefore important in engineering practice, often being the major factor governing the life and performance of machine components.
6. In addition to various possible chemical reactions from the elements and
compounds （化合物） present, environmental corrosion of components and
structures is a major concern, particularly at elevated temperatures and other
transportation vehicles.
7. From the beams in our homes to the wings of an airplane, there must be an
appropriate melding of materials, dimensions, and fastenings to produce
structures that will perform their functions reliably for a reasonable cost over a reasonable lifetime.
8. Interchangeability is achieved by establishing a permissible tolerance, beyond
which any further deviation from the basic size of the part is not allowed.
二、 翻译段落（15分/每小题，共60分）
1. In any “real” problem there is never sufficient good, useful information; we seldom know the actual loads and operating conditions with any precision, and the analyses are seldom exact. While our mathematics may be precise, the overall analysis is generally only approximate, and different skilled people can obtain different solutions. In the study of engineering mechanics, most of the problems will be sufficiently “idealized” to permit unique solutions, but it should be clear that the “real world” is far less idealized, and that you usually will have to perform some idealization in order to obtain a solution.
2．A new machine is born because there is a real or imagined need for it. It evolves from someone’s conception of a device with which to accomplish a particular purpose. From the conception follows a study of the arrangement of the parts, the location and length of links (which may include a kinematic study of the linkage （连杆机构）), the places for gears, bolts, springs, cams, and other elements of machines. With all ideas subject to change and improvement, several solutions may be and usually are found, the seemingly best one being chosen.
命题人：黄军杰
庞晓平 组
题人：
审题人：
董小
闵
命题时间：
2011年12月 日
教务处制
学院 专业、班 年级 学号 姓名
公平竞争、诚实守信、严肃考纪、拒绝作弊
封
线
密
3．Broaching Machines（拉床）These machines push or pull broaches, either horizontally or vertically, to generate various external or internal surfaces. They are of relatively simple construction and are actuated hydraulically （液压地）and have only linear motion of the broach. Because of the great variety of shapes and parts involved, broaching machines are manufactured in a wide range of designs and sizes.
4．This need for more sophisticated tools has resulted in the creation of a new, unique family of manufacturing processes known as nontraditional manufacturing processes. Generally speaking, nontraditional processes differ from conventional processes (e. g., drilling, turning, and stamping) either by utilizing energy in novel ways or by applying forms of energy heretofore unused for the purpose of manufacturing. High-velocity material jets, pulsed magnetic fields, light beams, and electrochemical reactions are but a few of these new tools currently used to perform operations such as cutting, welding, deburring （去毛刺）, and forming.。