首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
职称考试
Please Fasten Your Seatbelts Severe turbulence (湍流)can kill aircraft passe...
Please Fasten Your Seatbelts Severe turbulence (湍流)can kill aircraft passe...
admin
2020-12-24
24
问题
Please Fasten Your Seatbelts
Severe turbulence (湍流)can kill aircraft passengers. Now, in test flights over the Rocky Mountains, NASA (美国航空航天局)engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise. Invisible to radar, it is difficult to forecast and can hurl (用力拋出去)passengers about the cabin. In December 1997, one passenger died and a hundred others were injured when unexpected rough air cause a United Arlines flight over the Pacific to drop 300 metres in a few seconds.
However, passengers can avoid serious injury by fastening their seatbelts. “ It is the only antidote (对策)for this sort of thing, ” says Rod Bogue,project manager at NASA’s Dryden flight Research Center in Edwards, California.
The centre’s new turbulence detector is based on lidar, or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect. The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane’s airspeed. But as the particles swirl (打漩 )in rough air, their speed of approach increases or decreases rapidly. The rate of change in speed corresponds to the severity (激烈程度)of the turbulence.
In a series of tests that began last month, a research jet flew repeatedly into disturbed air over the mountain ridges (山脉)near Pueblo, Colorado. The lidar detector spotted turbulence between 3 and 8 kilometres ahead, and its forecasts of strength and duration
corresponded closely with the turbulence that the plane encountered.
Bogue says that he had “ a comfortable amount of time” to fasten his seatbelt. The researchers are planning to improve the lidar’s range with a more powerful beam. The system could be installed on commercial aircraft in the next few years.
In December 1997, a United Airlines flight hit unexpected rough air
选项
A causing a lot of damage to the plane.
B throwing its passengers out of the cabin.
C resulting in heavy casualties.
D forcing the pilot to make an emergency landing.
答案
C
解析
转载请注明原文地址:https://ti.zuoweng.com/ti/na9QKKKQ
相关试题推荐
Wouldyoupleasecallmyhusbandassoonaspossible?()A.visitB.phoneC.consult
Sheperseveredinherideasdespiteobviousobjectionsraisedbyfriends.(20...
Wouldyoupleasecallmyhusbandassoonaspossible?()A.visitB.phoneC.consult
Sheperseveredinherideasdespiteobviousobjectionsraisedbyfriends.(20...
Sheperseveredinherideasdespiteobviousobjectionsraisedbyfriends.A.pers
Thestormcausedseveredamage.AseriousBphysicalCaccidentalDenvironmental
Wouldyoupleasecallmyhusbandassoonaspossible?A:visitB:phoneC:consultD
Pleasecallmyhusbandassoonaspossible.A:contact B:consultC:phone D:visit
Shewillbeverypleasepleasedtomeetyou.A:angry B:happyC:sad D:unwilling
Shewillbepleasedtomeetyou.A:angry B:happy C:sad D:unwilling
随机试题
在特发性面神经麻痹的护理上应注意防止发生 A.面肌萎缩 B.面肌痉挛 C.
基建工程隐蔽工程验收中,运检单位(部门)明确需参加验收的隐蔽工程清单,并在开工前
B此题应为一笔画问题故答案为B。
可引起嗳气的原因有
“命运”,古人谓之“天命”。这种相信命运的观点在哲学上叫“宿命论”。它人的吉凶
在膨胀土地区的公路挖方边坡设计应遵循以下()选项中的原则。 A.尽量避免高边
2019年8月26日,习近平总书记主持召开中央财经委员会第五次会议时指出,我国____规模居全球首位,是全世界唯一拥有全部工业门类的国家。A、农业B、制造业
2014年10月28-29日,总局联合地方食药监局对广东怡康制药有限公司等企业开展检查。经检查发现,广东怡康制药有限公司委托韶关市居民制药有限公司生产抗骨...
水泥混凝土路面使用的外加剂包括()。A.早强剂B.缓凝剂C.减水剂D.引气剂E.增水剂
垄断资本主义发展的主要阶段包括()。A.私人垄断资本主义B.商业垄断资本主义C.金融垄断资本主义D.国家垄断资本主义E.工业垄断资本主义