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
2015-07-04
56
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 last paragraph tells us, among other things, that______.
选项
A、the lidar detector needs improvement
B、many airlines are interested in the system
C、passengers often forget to fasten their seatbelts
D、the lidar detector can be used in a wide range of areas
答案
A
解析
此题是根据最后一段的第二句“The researchers are planning to improve the lidar’srange with a more powerful beam.”出的题,这句的意思是说,研究人员正计划采用功能更强大的光束来提高雷达的测定范围。据此可以判断,雷达尚需改进,故A为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/CsLd777K
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
Thetomatojuiceleftabrownstainonthefrontofmyjacket.
StomachUlcerStomachulcersarethecauseofseverepainformanypeople.Doctorshavebeenabletohelplessenthepainof
Theword"mirror"inthefirstlinecouldbebestreplacedbyWhichofthefollowingstatementsisNOTtrueofBruceHardy?
AKeepingGoodRelationswithLocalBusinessmenBServiceProvidedbyLocalNewspapersCLargeCirculationoftheNationalNe
Thegirlisgazinaatherselfinthemirror.
AdifferenttechniquesBsocialrelationshipsandcommunicationClanguageandinformationDseveralcausesworkingtogetherEa
MindThoseMannersontheSubwaySo,thereyouare,justsittingthereinthesubwaycar,enjoyingthatbookyoujustbought
随机试题
症见胸膺满闷,短气喘息,稍劳即著,咳嗽痰多,色白黏腻或呈泡沫,畏风易汗,脘痞纳少,倦怠乏力,舌暗,苔薄腻,脉小滑。辨病为
A、25~40岁B、20~25岁C、40~50岁D、60~70岁E、40~60岁乳房纤维瘤好发年龄
患儿,女,11岁。1周前患上呼吸道感染,1天来全腹疼痛。查体:体温38.0℃,全腹压痛,轻度肌紧张和反跳痛,肠鸣音消失。腹腔穿刺抽出5ml稀薄无臭味脓液。诊断考虑
张某因打伤李某被公安局处以行政拘留15天的处罚,张某不服,申请行政复议。不久,受害人李某向法院提起刑事自诉,法院经审理认为张某的行为已经构成犯罪,判决拘役2个月。下列哪一选项是正确的?
引起国家责任的行为必须根据国际法能够归因子国家。或说该行为是国际法上的国家行为。下列哪些行为在国际法上被认为是国家行为?()
隧道开挖供风时,供风管前端至开挖面的距离宜保持在()m内并用分风器连接高压软风管。当采用导坑或台阶法开挖时,软风管的长度不宜大于()m。
后张法预应力混凝土简支梁施工要点包括()。
一批商品按期望获得50%的利润来定价,结果只销掉70%的商品,为尽早销售掉剩下的商品,商店决定按定价打折出售,这样所获得的全部利润是原来所期望利润的82%,问打了多少折扣?
简述实施差异化战略的最佳时机和风险。
在OSI模型中,提供路径选择功能的层次是______。
最新回复
(
0
)