首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Please Fasten Your Seatbelts Severe turbulence(湍流)can kill aircraft passengers. Now, in test flights over the Rocky Mountain
Please Fasten Your Seatbelts Severe turbulence(湍流)can kill aircraft passengers. Now, in test flights over the Rocky Mountain
admin
2016-07-17
38
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(用力抛出去)passengers about the cabin. In December 1997, one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters 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 kilometers 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.
The turbulence detector can tell the severity of the turbulence by measuring______.
选项
A、the speed of the plane
B、the speed of the light
C、the number of particles in the air
D、the changes of the particles’ speed
答案
D
解析
此题问气流探测器通过测量什么来判断它的激烈程度?第四段最后一句说“Therate of change in speed corresponds to the severity(激烈程度)of the turbulence.”所以选项D为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/5bLd777K
本试题收录于:
职称英语理工类B级题库职称英语分类
0
职称英语理工类B级
职称英语
相关试题推荐
HowTwoGreatConflictsHelpedtoChangeEuropeNinetyyearsagoonasunnymorninginNorthernFrance,somethinghappenedt
HowTwoGreatConflictsHelpedtoChangeEuropeNinetyyearsagoonasunnymorninginNorthernFrance,somethinghappenedt
MedicineAwardKicksoffNobelPrizeAnnouncementsTwoscientistswhohavewonpraiseforresearchintothegrowthofcancer
TheproblemfacingBritishsurgeonsintheearly19thcenturywasthatThebodysnatchersusedwoodenshovelsbecause
InitiallythewriterdidnotwanttobuyahearingaidbecauseAccordingtothepassage,hearinglossis
ThefirstparagraphsuggeststhatbothdreamsandfunctionsofdreamsareWhichdreamfunctionis’NOTmentionedinthepassage
Thegirlisgazinaatherselfinthemirror.
Once-dailyPillCouldSimplifyHIVTreatmentBristol-MyersSquibbandGileadScienceshavecombinedmanyHIVdrugsintoasi
Psychologistsaredividedwithregardtotheirattitudestoward______.Thephrase"tokeneconomies"(Line1,Para.5)probably
MindThoseMannersontheSubwaySo,thereyouare,justsittingthereinthesubwaycar,enjoyingthatbookyoujustbought
随机试题
Althoughinitiallyitmaybedifficulttodiscerntheessay’smessageofpeaceandconciliation,aclosereadingrevealsitsess
舌苔黑而润滑多属
男,32岁。便秘2年,3日前排便用力后肛门剧痛,近2日大便时和排便后肛门疼痛加重,粪便干硬,且其表面及便纸上附有鲜血,其诊断可能为
以下有关热原性质的描述,错误的是
电弧焊焊接时,选用直流电源的优势有()。
作家何某是一名自由职业者,2012年开了一家书店并取得个体工商户营业执照,其2012年收入如下:①被某电视台“五一”文艺晚会组聘为顾问,取得顾问费4000元。②在某高校中文系兼课,每月两次,每次课酬400元。③与某高校两位老师共写一本书,共得稿费24
根据以下图表资料,回答下列小题。以下3个表格呈现了全国2012年1~10月份房地产开发、销售情况,请根据表格信息,回答问题。2012年1-10月,房地产开发企业资金的主要来源是()。
在今年的“世界穿山甲日”即将来临之际。食用穿山甲事件在我国网络上闹得_______。穿山甲是我国重点保护野生动物,目前在我国几近灭绝,比大熊猫还要_______。但是,我国食用、药用穿山甲的历史悠久,对穿山甲有巨大的市场需求。这种需求还导致穿山甲国际走私严
Thefarmerputupironfencesaroundtheflower_____gardenneighbor’ssheepshouldbreakin.
Whatdoesthespeakermean?
最新回复
(
0
)