Fasten Your Seatbelts Severe turbulence can kill aircraft passengers. Now, in test flights over the Rocky Mountains, NASA engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it. However, passengers can avoid serious injury by fastening their seatbelts. It is the only antidote for this sort of thing, says Rod Bogue, project manager at NASAs The centres 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 planes airspeed. But as the particles swirl in rough air, their speed of approach increases or decreases rapidly. The rate of change in speed corresponds to the severity of the turbulence. Bogue says that he had a comfortable amount of time to fasten his seatbelt. The researchers are planning to improve the lidars range with a more powerful beam. The system could be installed on commercial aircraft in the next few years. A A not very rough storm. C A kind of visible storm. 37 In December 1997, a United Airlines flight hit unexpected rough air B throwing its passengers out of the cabin. D forcing the pilot to make an emergency landing. A the speed of the plane. C the number of particles in the air. 39 We can infer from the fifth paragraph that B researchers are not sure about the effectiveness of the lidar detector. D no more test flights are needed. A the lidar detector needs improvement. C passengers often forget to fasten their seatbelts. 【参考答案】36. B37. C38. D39. A40. A
2017届浙江省高考英语一轮复习专题课件:第1部分专题5 动词的事态和语态
2017两会热词汇总
国际英语资讯:Trump defends his claim of being wiretapped by predecessor
体坛英语资讯:Ghana Olympic Committee elects Ben Nunoo as president
体坛英语资讯:Champions League quarterfinalists set as Monaco, Atletico move forward
2017届浙江省高考英语一轮复习专题课件:第1部分专题11 特殊句式
国内英语资讯: China cuts U.S. treasury holding in January
2017届高考英语大一轮复习课件:选修8 module5《the conquest of the universe》(外研版)
2017届高考英语一轮单元复习精讲课件:第1部分 必修1 Unit2《English around the world》(人教版新课标)
黑客帝国成真?知识或可直接上传到大脑
2017届高考英语大一轮复习课件:必修4 module4《great scientists》(外研版)
2017届浙江省高考英语一轮复习专题课件:第2部分 题型专题突破 专题3 任务型阅读
国内英语资讯: WFP welcomes Chinas support for Syrian refugees in Jordan
2017届浙江省高考英语一轮复习专题课件:第1部分专题2 代词和介词
国内英语资讯: South China Sea tsunami alert center expected to go on trial in 2017
2017届浙江省高考英语一轮复习专题课件:第1部分专题7 情态动词和虚拟语气
2017届浙江省高考英语一轮复习专题课件:第1部分专题10 并列句和状语从句
2017届浙江省高考英语一轮复习专题课件:第1部分专题3 形容词和副词
2017届浙江省高考英语一轮复习专题课件:第2部分 题型专题突破 专题2 第3讲 词义猜测题
2017届高考英语大一轮复习课件:必修4 module3《body language and non-verbal communication》(外研版)
2017届高考英语大一轮复习课件:必修4 module1《life in the future》(外研版)
国内英语资讯: Chinese envoy calls for enhanced efforts to combat human trafficking
2017届高考英语一轮单元复习精讲课件:第1部分 必修2 Unit2《The Olympic Games》(人教版新课标)
2017届浙江省高考英语一轮复习专题课件:第2部分 题型专题突破 专题2 第5讲 篇章结构题
2017年高考英语考前阅读、完型与写作(命题揭秘)之阅读理解:思路点拨(含解析)
2017届浙江省高考英语一轮复习专题课件:第1部分专题1 名词和冠词
2017年高考英语考前阅读、完型与写作(命题揭秘)之阅读理解:专项训练(含解析)
2017届浙江省高考英语一轮复习专题课件:第2部分 题型专题突破 专题1 完形填空
2017届高考英语一轮单元复习精讲课件:第1部分 必修2 Unit3《Computers》(人教版新课标)
国内英语资讯: China plans to add 136 airports by 2025
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |