电网对所选高压开关设备的技术要求有哪些?

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问题:

电网对所选高压开关设备的技术要求有哪些?

考点:电网运行及调度考试电网运行及调度考试题库
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下表是几种物质的凝固点和沸点.

物质凝固点/℃沸点/℃
水银-38.8357
酒精-11778.5
0100
(1)南极的最低温度为-88.3℃,应选用______温度计来测量南极气温;

(2)在标准大气压下,沸水的温度为100℃,应选用______温度计来测量沸水温度.

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B

Energy-saving Finns invented the first ice skate more than 5,000 years ago, as a practical method of transport to make getting across frozen lakes less of a struggle.

The earliest skates would have been blades made from bones and are one of the oldest means of transport ever discovered —they may even have been essential survival tools.

Researchers at Manchester Metropolitan University have calculated that ice skates would have saved energy by 10 percent, and suggest that they were developed for practical use and were not used for recreation, as they are today.

They think the most likely birthplace of skating is southern Finland, where there are many icy lakes.

The scientists have put their theory to the test and made replica(复制品) skates modeled after examples held at the British Museum and the Fitzwilliam Museum in Cambridge.

Volunteers on ice rinks in the Alps had their heart rates, oxygen intake and skating speeds measured while they skated with the replica skates. From this experiment, re-searchers were able to calculate energy consumption and the efficiency of their skating. They discovered that skating over the land in ancient Fin-land would have saved 10 percent of people’s energy. The result is based on the fact that Finland has the highest concentration of lakes in the world. The ancient Finnish people could benefit more than others from developing this tool for transport.

In a time and environment in which the balance between energy taken from food and energy required to live was crucial; the least cost of energy might have helped humans survive in extreme conditions.

45. The first ice skate invented by the Finns was used for _____.

A. recreation                           B. transportation across lakes 

C. saving energy                       D. sports

46. The birthplace of skating might be southern Finland because _____.

A. there are many icy lakes there  

B. people need more oxygen to breathe in there

C. people feel tired easily there   

D. transportation there is more difficult

47. Scientists have experimented with replica skates and found that with those skates the ancient

Finnish people would have _____.

A. crossed a lot of lakes

B. saved 10 percent of energy when crossing the lakes

C. climbed the Alps easily 

D. otherwise wasted a lot of food and energy

48. It can be inferred from the story that _____.

A. the Finnish people were clever enough to invent the practical skates

B. there were a lot of lakes in ancient Finland

C. the living conditions were very hard for the ancient Finnish people

D. it was very cold in ancient times in Finland

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为下列一则新闻报道拟一个标题,最准确的是

2008年6月18日,青海湖国际沙雕与大地艺术节开幕式上,揭晓了青海湖形象标识和主题宣传词。青海湖形象标识和主题宣传词公开征集活动自去年8月展开,得到了社会各界的广泛关注和支持。征集活动中,共收到545人应征形象标识作品751件;收到938人应征主题宣传词来稿7028条。经在全社会公开征求意见和评审委员会认真评选,最终选定了一个青海湖形象标识和“高原蓝宝石、梦幻青海湖”、“天高尘世远、宁静青海湖”等8条主题宣传词。

A.青海湖国际沙雕与大地艺术节开幕

B.青海湖形象标识和主题宣传词揭晓

C.青海湖形象标识公开征集与评选活动

D.青海湖主题宣传词公开征集与评选活动

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数据独立性是指( )。

A.数据库管理系统与数据库的相互独立
B.用户应用程序与数据库的数据相互独立
C.应用程序与数据库管理系统的相互独
D.数据库管理系统与操作系统的相互独立

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信用证要求装运港装船时检验,签发证单日期为提单日期( )内(含提单日)。

A.一天
B.两天
C.三天
D.五天

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