问题 阅读理解与欣赏

“鸟巢”的抗震妙招

  北京奥运会的国家奥林匹克体育中心由于形似鸟巢,因此被人们称为“鸟巢”。“鸟巢”跨度很大,钢梁包裹着主体育场,中间悬空,共能容纳9.1万观众观赏比赛。在汶川发生8.0级地震之后,“鸟巢”的抗震性能也就备受公众的关注。但专家告诉我们,“鸟巢”能抵御8级地震。

  乌鸦是一种常见的鸟类,但是它的鸟巢可不简单。它会采集许多粗枝,边编织,边用泥粘土加固,直到做成一个盆状巢。当然,天然的鸟巢有繁有简,但都有共同的特点,它们都是凹底,这便于鸟蛋聚集在巢中央,使鸟蛋更安全,而且在孵化时使温度不易流失。更重要的是,盆状的鸟巢在抵抗风雨和树枝的晃动方面也很有效。当大风吹到弧形的边缘时,强烈的气流会顺着边缘滑过,鸟巢承受的风力大大减弱了。鸟巢往往修建在三条甚至更多的树枝分叉的位置,树枝如同钢梁一样支撑了盆状的鸟巢。所以当鸟巢所在的大树晃动时,盆状的鸟巢比其他形状更难以倾覆。

  我们知道,人类修建在地面上的大型建筑,都要向地下打坚固的地基,“鸟巢”也不例外,它的地基有效支撑了地面的建筑,类似于树干和树枝对天然鸟巢的支撑作用。只是人类所打的地基更深、更结实。然而,地震专家在借鉴天然鸟巢的基础上,又在自己的建筑中加了许多鸟类巢穴所没有的抗震技术。地震专家们知道,对于大型建筑来说,那种全部联为坚固整体的建筑并不是最抗震的,反而是不同部分可以分别适度位移的建筑,能够自行消耗掉大量的地震波能量,因而更抗震。

  首先,钢梁结构和包含观众席的的碗状看台是分离的,这个设计很科学,因为钢梁结构是钢铁材料,而看台是混凝土材料,在地震时的震动频率不一样,如果联成一体,由于伸缩程度不同而相互拉扯,反而容易造成难以预料的破坏。另外,从世界范围内的防震经验来看,“鸟巢”的钢梁结构异常坚固,应该可以抵御大地震的袭击。钢梁结构又分为三个层次,其中一层环绕一周,起到支撑的作用,还有一层专门支撑楼道,这些设计都使地震来时,场馆钢梁结构部分安然无恙。其次,碗状看台也分为8个独立的大单元,当地震来时每个单元都独立晃动,能够有效消减地震波的冲击力。

  此外,在建筑的过程中,经过对安全问题的慎重考虑,设计师们取消了原来设计方案中的可伸缩顶棚,使得体育馆的抗震能力进一步得到了加强。由于观众席每一层疏散通道都是独立的,没有交叉,人员疏散可以在8分钟内完成。

  所以,就算遭受了强烈地震冲击,“鸟巢”体育馆仍然是非常安全的。

1、根据文意,下列对“鸟巢”抗震设计的妙招,理解不正确的一项是[ ]

A、借鉴天然鸟巢的盆形和凹底结构,并在“鸟巢”的底部向地下打进更深更坚固的地基。

B、把钢梁结构和观众席的碗状看台实行分离建造,而不是让“鸟巢”全部联成一个整体。

C、钢梁结构分为三个层次,每层都有它的特定的功能。碗状的看台也分为独立的几大单元。

D、“鸟巢”取消了原设计中的可伸缩的顶棚,观众席每一层疏散通道都是独立的,没有交叉。

2、下列理解和分析,符合原文意思的一项是 [ ]

A、天然鸟巢往往建在分叉的树枝之间,再加上它的盆形结构,因此,鸟巢有很强的抵抗风雨和地震的能力。

B、不同建筑物之间可以适度位移,这样就能够消耗掉大量的地震波能量,因而更抗震。 “鸟巢”的设计体现了这一原理。

C、“鸟巢”的钢梁结构和看台实行分离设计,因此,“鸟巢”不是以整体来承受地震,而是不同部分分别承受地震。

D、“鸟巢”的钢梁结构异常坚固,完全可以抵御大地震的袭击。就算遭受了强烈地震冲击,“鸟巢”仍然会是安全的。

3、依据原文提供的信息,下列推断正确的一项是 [ ]

A、为了让“鸟巢”容纳尽可能多的观众,因此“鸟巢”采用了这种跨度很大,钢梁包裹着主体育场,中间悬空的设计。

B、鸟类筑造的鸟巢盆形结构带给建筑师们有益的启示,再一次有力地说明了人与自然和谐相处,保护动物的必要性。

C、不同建筑材料在地震时的震动频率不一样,因此一些大型建筑可以把不同材料构成的部分独立开来,这样会更抗震。

D、从“鸟巢”的外形、结构、容量、建造过程等方面来看,“鸟巢”可以说是世界上最宏伟、最具科技含量的建筑物。

答案

1、D

2、C

3、C

单项选择题


Part A
Text 1

To try to bring context back, Hueter and Burgess teamed with NOAA and Sea Grant to hold a press conference in the spring of 2002 at the National Press Club. "We wanted to try to get the press to adopt some rules of engagement," Hueter says. "We wanted them to calm hysteria, use perspective and write more articles not focusing on attack."
Burgess and Hueter stress sharks’ importance in the ecological balance and health of the oceans, which depend on complex food webs involving every sea creature. Just like apex land predators, sharks are important in that balance. "They’re a top predator and few in number," Hunter says. "When they’re eliminated, there’s nothing to fill in that place."
More than 100 million sharks are killed each year by fishermen, which can devastate certain species that grow slowly and can take as long as 15 to 20 years to reach reproductive age.
The prehistoric creatures continue to fascinate scientists with their immune and reproductive systems and their advanced senses and they’ve been used as a classic vertebrate anatomy tool for years because they bear many similarities to humans.
Scientists believe that unprovoked attacks are cases of mistaken identity, or the sharks just having a taste to see whether they want some more. Most of attacks are not fatal. According to the International Shark Attack File, globally, there were 55 unprovoked attacks in 2003, with four fatalities. In the US, one is 30 times more likely to be struck by lightning than to be attacked by a shark, and bees, wasps and snakes cause more deaths each year than sharks.
The number of attacks seems to have risen dramatically in the 1990s, but this is partly attributed to more thorough record-keeping by the International Shark Attack File and more public awareness leading to more reports. Also, the number of shark-human contacts in a year is directly proportional to the number of humans in the sea. As the world population increases and more and more people, take to the waters, it is logical that shark attacks, along with other water-related injuries, will increase. Due to overfishing, shark populations are seriously declining in some cases and holding at reduced numbers in others.
According to George Gerbner’s Cultivation Theory, people can be affected by the amount and the content of the TV and movies they watch. The portrayals of things in these media can create a false sense of society. For example, one who watches a lot of crime shows could perceive the world to be a much more dangerous place than it actually is. So be it with TV shows and movies that feature shark attacks. Things can appear to be more common than they actually are. But this isn’t the only reason people fear sharks--sharks do have teeth and can bite. Humans could see other predators coming and kill them with a single shot, but in shark territory, the predator is invisible.

Why are sharks important in the ecological balance and health of the oceans

A.They are apex carnivores and reduced in numbers.

B.They are killed and few in numbers.

C.They are certain species that grow slowly.

D.They are flesh-eating animals and kill other sea creatures.

填空题