SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING LESSON TWO FUNDAMENTALS OF PAPER WRITING(I) The fourth method: Definition a dictionary will give you two different definitions of the word definition: ()"a statement of what a thing is"and(2)a"a statement or explanation of what a word or phrase means or has meant. In the strict sense, a definition, as we shall use the word here, is not of a thing, but of a word, or of a process The process of making a definition is not, however, a mere game of words. It is clear that we cannot make a useful definition without knowledge of the thing"'(that is, object event, idea, etc. )to which the word(or term) refers. And it is equally clear that the definition of a word communicates knowledge about the"thing" referred to. A definition does give knowledge of "what a thing is, and equally important, may lead the maker of definition to clarify his own thoughts on the nature of the"thing
SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING LESSON TWO FUNDAMENTALS OF PAPER WRITING (Ⅱ) The Fourth Method: Definition A dictionary will give you two different definitions of the word definition: (l) "a statement of what a thing is" and (2) a "a statement or explanation of what a word or phrase means or has meant. " In the strict sense, a definition, as we shall use the word here, is not of a thing, but of a word, or of a process. The process of making a definition is not, however, a mere game of words. It is clear that we cannot make a useful definition without knowledge of the “thing” (that is, object, event, idea, etc.) to which the word (or term) refers. And it is equally clear that the definition of a word communicates knowledge about the "thing" referred to. A definition does give knowledge of "what a thing is, " and equally important, may lead the maker of definition to clarify his own thoughts on the nature of the "thing
SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING In fact. a description can often serve as a definition b y enlightening us about a thing, it enlightens us about the use of the term that refers to the thing. For example, we find later in this chapter a description of the mechanism used to lift liquids and when we have finished reading that, we know how to define the term jet pump. But for the moment, we are not concerned with description as a form of definition, nor concerned with certain other kinds of definition(for instance, what is known as recursive definition in arithmetic and grammar). We, instead, are concerned with traditional, or classic, definition, which goes back as far as Aristotle.Our discussion is confined to that form
SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING In fact, a description can often serve as a definition: by enlightening us about a thing, it enlightens us about the use of the term that refers to the thing. For example, we find later in this chapter a description of the mechanism used to lift liquids, and when we have finished reading that, we know how to define the term jet pump. But for the moment, we are not concerned with description as a form of definition, nor concerned with certain other kinds of definition (for instance, what is known as recursive definition in arithmetic and grammar). We, instead, are concerned with traditional, or classic, definition, which goes back as far as Aristotle. Our discussion is confined to that form
SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING a definition locates its subject in a class and then proceeds to point out the characteristics that make it differ from other items in that class and that, therefore, allow it to be assigned to a subclass. This process is, it is clear, a special variant of the process of classification. A definition simply sets its subject in a limited scheme of classification The process of definition is, like classification, a natural way the mind works. It is no more arbitrary than other methods of exposition we have studied. We make definitions constantly and instinctively. Let us examine an example of how the process works
SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING A definition locates its subject in a class and then proceeds to point out the characteristics that make it differ from other items in that class and that, therefore, allow it to be assigned to a subclass. This process is, it is clear, a special variant of the process of classification. A definition simply sets its subject in a limited scheme of classification. The process of definition is, like classification, a natural way the mind works. It is no more arbitrary than other methods of exposition we have studied. We make definitions constantly, and instinctively. Let us examine an example of how the process works
SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING Manipulator is usually considered as a sequence of rigid links connectedmanipulator机械手 by joints with actuators. We can‖ rigid link刚性接头 construct the dynamic equations of motion for a manipulator from theactuator执行器 kinematic structure and the link parameters of the manipulator. Each kinematic structure link of a manipulator has 10 link 运动结构 parameters that consist of the mass, the inertia tensor location of center of mass and the‖惯性张量 inertia tensor. All the link parameters of redundant多余的, a manipulator are redundant in the‖重复的 sense that the same dynamic equation happens to be generated even if the link parameters take different values. (c)
SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING Manipulator is usually considered as a sequence of rigid links connected by joints with actuators. We can construct the dynamic equations of motion for a manipulator from the kinematic structure and the link parameters of the manipulator. Each link of a manipulator has 10 link parameters that consist of the mass, the location of center of mass and the inertia tensor. All the link parameters of a manipulator are redundant in the sense that the same dynamic equation happens to be generated even if the link parameters take different values.(c) manipulator 机械手 rigid link 刚性接头 actuator 执行器 kinematic structure 运动结构 inertia tensor 惯性张量 redundant 多余的， 重复的
SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING (c)This is caused from the fact that two adjacent links are connected by a adjacent link相邻接头 joint and the relative motions of the adjacent links are of one degree-of- degree-of-freedom freedom.Then, what are the‖自由度的 parameters that are non-redundant and enough to generate the dynamic base parameter基础参数 equations for a manipulator? This is a very natural and fundamental question Such parameters will be called base parameters
SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING (c)This is caused from the fact that two adjacent links are connected by a joint and the relative motions of the adjacent links are of one degree-offreedom. Then, what are the parameters that are non-redundant and enough to generate the dynamic equations for a manipulator? This is a very natural and fundamental question. Such parameters will be called base parameters. adjacent link 相邻接头 degree-of-freedom 自由度的 base parameter 基础参数