问题 单项选择题

机械设备可造成碰撞、夹击、剪切、卷入等多种伤害。所以识别机械设备的危险部位非常重要。下列机械设备部位,不属于危险部位的是( )。

A.旋转部件和成切线运动部件问的咬合处

B.金属刨床的工作台

C.机床底座

D.旋转的凸块

答案

参考答案:C

解析: 机械设备的危险部位的危险部位主要包括:①旋转部件和成切线运动部件问的咬合处,如动力传输皮带和皮带轮、链条和链轮、齿条和齿轮等;②旋转的轴,包括连接器、心轴、卡盘、丝杠和杆等;③旋转的凸块和孔处,含有凸块或空洞的旋转部件是很危险的,如风扇叶、凸轮、飞轮等;④对向旋转部件的咬合处,如齿轮、混合辊等;⑤旋转部件和固定部件的咬合处,如辐条手轮或飞轮和机床床身、旋转搅拌机和无防护开口外壳搅拌装置等;⑥接近类型,如锻锤的锤体、动力压力机的滑枕等;⑦通过类型,如金属刨床的工作台及其床身、剪切机的刀刃等;⑧单向滑动部件,如带锯边缘的齿、砂带磨光机的研磨颗粒、凸式运动带等;⑨旋转部件与滑动之间,如某些平板印刷机面上的机构、纺织机床等。

多项选择题
单项选择题

What is a knowledge worker Knowledge workers are people who routinely use a computer in their work to enhance their productivity. She or he is the critical component in a computer system. A computer system is made up of people, using data and procedures to work with software and hardware components. It takes all five working together to produce results. Knowledge workers are white-collar professionals from many walks of life who have the following characteristics.

They understand how to use a personal computer.

They know how to work with computer-based information.

They understand how the computer benefits their work and the business.

They regard the computer as a productivity tool.

Knowledge workers may be employed in a company of any size, large or small, at a wide range of tasks. They may be self-employed, working in their own office or at home. They may be sales representatives or managers who travel with a portable computer. Students are knowledge workers as well. Many of you may be preparing for a career in knowledge work in office automation, public relations, account supervision, social work, management, or a number of other occupations.

Today, there are over 70 million knowledge workers in the United States, who generate nearly 2 trillion pieces of paper each year. These knowledge workers work 10 hours per week more than they did 10 years ago, and create over 15 billion new pieces of paper a year. According to a survey conducted by Industry Week magazine in 1990, 39 percent of U. S. management-level knowledge workers say paperwork is a problem. Further, USA Today reported in 1991 that the average knowledge worker has 36 hours of work stacked up on the desk. Clearly, the computer as a productivity tool must play an ever more important role in knowledge work and knowledge work itself is steadily assuming larger proportions. According to several worldwide studies, urban centers in Canada, the United States, Europe, and other developed areas are increasingly using computer technology and thus evolving knowledge-based cities. These knowledge-based cities are characterized by. (1) a concentration of scientists and engineers, (2) business, university, and governmental research activities, (3) a high degree of interaction between individuals and the various institutions, and (4) a positive image that attracts college graduates to knowledge work. Clearly, the decade of the 1990s and the new millennium that follows are an exciting time for knowledge work.

Which of the following is true according to the passage().

A. Knowledge workers using computers are creating less paper every year.

B. Knowledge workers using computers are creating more paper every year.

C. Knowledge workers using computers are creating the same amount of paper every year.

D. Knowledge workers using computers are creating new kind of paper every year.