问题 问答题 简答题

露天采矿中常用的控制爆破有哪些?各用于什么情况?

答案

参考答案:

露天矿山常用的控制爆破有:预裂爆破、缓冲爆破和光面爆破。

适用情况:

预裂爆破:适用于靠帮或并段时;

缓冲爆破:位于预裂孔和主生产炮孔之间的一排炮孔为缓冲孔,缓冲孔与预裂孔同时起爆,或略迟于预裂孔起爆;

光面爆破:在靠帮或并段的位置线、出入沟的两侧边界线上时使用。

阅读理解

Before the widespread use of computers, managers could not make full use of large amounts of valuable information about a company’s activities. The information either reached managers too late or was too expensive to be used. Today, managers are facing a wide range of data processing and information instruments. In place of a few financial controls, managers can draw on computer-based information systems to control activities in every area of their company. On any kinds at performance measures, the information provided by these systems helps managers compare standards with actual results, find out problems, and take corrective action before it is too late to make changes.

The introduction of computerized information systems has sharply changed management control in many companies. Even a neighborhood shopkeeper may now use computers to control sales and other activities. In large companies, electronic data processing systems monitor entire projects and sets of operations.

Now, there are about 24 million microcomputers in use in the United States, one for every 10 citizens. It is estimated that by 1996, 61 percent of American managers will be using some sort of electronic workstation. In order for managers to be sure that the computer-based information they are receiving is accurate, they need to understand how computers work. However, in most cases they do not need to learn how to program computers. Rather, managers should understand how computerized information systems work; how they are developed; their limitations and costs; and the manner in which information system may be used. Such an understanding is not difficult to achieve.

One research found that business firms were more successful in teaching basic information about computers to business graduates than they were in teaching business subjects to computer science graduates.

46. In the second paragraph the author mentions a neighborhood shopkeeper to show that _____.

A. few people could afford a computer

B. computer is now becoming more and more widely used in business

C. only shopkeepers are wealthy enough to buy computers

D. computer is far more intelligent than man as far as business is concerned

47. From the third paragraph we learn that ________.

A. it is essential that managers know how to program computers

B. managers may sometimes receive inaccurate information from computers

C. in most companies, an employee has to share a computer with at least 9 other employees

D. computerized information system is perfect in every way

48. All of the following statements are true EXCEPT that _________.

A. computer science graduates are quick to learn business subjects because of their professional knowledge about computers

B. with the help of computers, company mangers are now more informed of what’s going on in their companies

C. computer is a great help for business management

D. computerized information enables managers to take timely measures to prevent possible mistakes

49. According to the passage, which of the following statements is right?

A. It’s a difficult task for the managers to deal with a wide range of computer-based information daily.

B. The introduction of computerized information system is a revolution in management

C. In order to perform good management, managers need to have much knowledge about computer.

D. A good knowledge of computer leads managers to success

50. What is the passage mainly about?

A. How to teach information about computers to business graduates.

B. Computer’s growing popularity nationwide.

C. Application of computer in business management.

D. Computer training program for mangers.

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