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【简答题】

“Yes, ladies and gentlemen, welcome aboard NASA’s Space Elevator. We’re going to leave soon. The entire ride will take about five hours, so sit back and enjoy the trip. As we rise, be sure to look out the window. You’ll see the sky change from deep blue to black. It is one of the most wonderful views(景色)you will ever see! ” Does this sound like the Sci-Fi Channel? Well, it’s not. Scientists are thinking that a “space elevator” will be possible toward the end of the 21st century. A space elevator will consist of a long cable (电缆) from the Earth’s suce into space to an altitude(高度) of about 35,786 km. “Elevators” will travel along the cable and move people and loads between Earth and space. One of the greatest advantages is that the cost will be much less. Researchers estimate (估计) that a passenger with baggage at 150 kg might cost only $222! Compare that to today’s cost of around $3.3 million for the same weight. It would make “cheap” space travel possible. Scientists believe carbon nanotubes (纳米管) may be used to make high-strength materials for the cables, although they are still being studied. It was Arthur C. Clarke who brought this idea to the general public. In his science fiction novel Fountains of Paradise, engineers build a space elevator on top of a mountain peak on an island. One day, Clarke was asked a question by a student during his speech. The student asked when the space elevator would become a reality. Clarke answered, “Probably about 50 years after everybody stops laughing.” He’s got a point. When we stop thinking of something as impossible, then we start working on its development. 小题1:Why should passengers in a space elevator look out the window while they are moving into space? A.Because the blue sky is very beautiful. B.Because the view outside is wonderful. C.Because the sky changes from black to blue. D.Because the trip will take about seven hours. 小题2:Which of the following is NOT true according to the passage? A.Scientists haven’t used carbon nanotubes to make the cables. B.Traveling in space elevators will cost much less in the future. C.Passengers will be able to travel in space elevators with baggage. D.Space elevators will travel for 35,786 km around the Earth’s suce. 小题3:What is the best title for this passage? A.Possible Now: Space Travel B.Cheap Space Travel C.Going into Space in an Elevator D.Space Travel — Impossible

题目标签:电缆估计
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【多选题】区间估计依据需要依据()

A.
样本指标
B.
总体指标
C.
可信程度
D.
对分布分位点

【单选题】YZW电缆用途为( )。

A.
敷设在无机械外力作用的户内电缆沟及管子中
B.
敷设在有侵蚀性介质、无机械外力作用的户内电缆沟道及管子中
C.
敷设在地下或电缆沟道中能承受机械外力作用,但不能承受大的拉力
D.
连接各种移动式电气设备,能承受较大机械拉力,还具有耐严酷气候和一定的耐油性能

【多选题】工作时间估计的依据有( )。

A.
工作清单
B.
工程量清单
C.
约束条件
D.
资源配备
E.
资源效率

【单选题】KVV22 10*2.5中“10”表示电缆的()。

A.
标称截面
B.
芯数
C.
导体中单丝根数
D.
铠装层数

【单选题】样本含量估计

A.
根据实际情况能选多少是多少
B.
经济条件允许的情况下越多越好
C.
时间允许的情况下越多越好
D.
调查整个总体最好
E.
保证研究结论具有一定可靠性的前提下确定的最小例数

【单选题】电缆水底敷设时,()。

A.
应悬于水中
B.
应埋入河床1m以下
C.
应平放于水底