久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

 
 
 

當前位置: Language Tips> 新聞播報

Scientists finalize test platform for ultra-speed maglev train

中國日報網 2014-05-15 10:11

 

Get Flash Player

Download

Chinese scientists have built the world's first prototype testing platform for an ultra-high-speed vacuum maglev train, which theoretically could hit speeds up to 2,900 km per hour, or almost three times the speed of a passenger jet, researchers confirmed on Wednesday.

Running the maglev train in a near-vacuum environment is the best way to ensure the comfort and energy economy of an ultra-high speed train, said Deng Zigang, head of the project team based in Southwest Jiaotong University in Sichuan's capital Chengdu.

When a train's speed reaches 400 km per hour or above, Deng said, more than 83 percent of the traction is wasted to offset air resistance and the aerodynamic noise is over 90 db, higher than the 75 db set by design standards.

Southwest Jiaotong University developed the initial high temperature superconducting magnetic levitation test loop in March 2013, and the latest model had the vacuum pipe that became the world's first evacuated tube transport system.

When the train runs in the tube, the pressure inside is 10 times lower than outside and the train can use more power for driving at high speed, Deng said.

From the point of design, the vacuum ultra-high-speed maglev train uses two different technologies to increase the speed of the train, said Zhao Lin, an associate research fellow of the National Lab for Superconductivity, Institute of Physics at the Chinese Academy of Sciences.

The first is magnetic levitation, which uses superconductors to produce powerful magnets to elevate the train above the track, thus remove the friction with the track and enhance the speed.

"The reason that an aircraft moves faster than any vehicle on the ground is similar - the friction from the air is much smaller than the ground," Zhao explained.

The concept of maglev transportation was first presented in the mid-20th century and the first commercial maglev train line was put into operation at Birmingham Airport in Britain in 1984, which had a speed of only 42 km per hour because of the technology at that time.

Currently, China and Japan are actively developing such technology, and the maglev train connecting the Bund and Pudong Airport in Shanghai is the world's fastest commercial line with speeds up to 431 km per hour.

The second technology used to speed up the train is to put it into a vacuum tube to reduce air resistance, which is the only source of friction for a magnetic levitation train.

"Compared with conventional superconductors, the high-temperature superconductors require less stringent environmental demands, and thus reduce the cost of the train," Zhao said.

For example, the conventional superconductors used on Japan's levitation trains need to stay at about -270 C to keep their superconducting state, which needs liquid helium cooling.

In contrast, high-temperature superconductors of the maglev train running in Pudong Airport can keep the superconducting state at -180 C to -200 C, which can be refrigerated with liquid nitrogen, a cooling agent one hundred times cheaper than liquid helium.

However, there are major technological problems to resolve before the train could be put in to use.

"For example, the train would need a vacuum tube that extends hundreds of kilometers. And it is challenging to maintain such a large vacuum system," Zhao said.

"Also, there could be external impacts like earthquakes that could pose a threat to the system. And the braking system of the train at such high speed also needs non-traditional designs."

Questions:

1. What university is the project team based at?

2. What year was the first commercial maglev train put into operation?

3. How fast does the world’s fastest maglev train travel?

Answers:

1. Southwest Jiaotong University.

2. 1984.

3. 431 km/hr.

(中國日報網英語點津 Helen 編輯)

Scientists finalize test platform for ultra-speed maglev train

About the broadcaster:

Scientists finalize test platform for ultra-speed maglev train

Lance Crayon is a videographer and editor with China Daily. Since living in Beijing he has worked for China Radio International (CRI) and Global Times. Before moving to China he worked in the film industry in Los Angeles as a talent agent and producer. He has a B.A. in English from the University of Texas at Arlington.

 
中國日報網英語點津版權說明:凡注明來源為“中國日報網英語點津:XXX(署名)”的原創作品,除與中國日報網簽署英語點津內容授權協議的網站外,其他任何網站或單位未經允許不得非法盜鏈、轉載和使用,違者必究。如需使用,請與010-84883561聯系;凡本網注明“來源:XXX(非英語點津)”的作品,均轉載自其它媒體,目的在于傳播更多信息,其他媒體如需轉載,請與稿件來源方聯系,如產生任何問題與本網無關;本網所發布的歌曲、電影片段,版權歸原作者所有,僅供學習與研究,如果侵權,請提供版權證明,以便盡快刪除。

中國日報網雙語新聞

掃描左側二維碼

添加Chinadaily_Mobile
你想看的我們這兒都有!

中國日報雙語手機報

點擊左側圖標查看訂閱方式

中國首份雙語手機報
學英語看資訊一個都不能少!

關注和訂閱

本文相關閱讀
人氣排行
搜熱詞
 
 
精華欄目
 

閱讀

詞匯

視聽

翻譯

口語

合作

 

關于我們 | 聯系方式 | 招聘信息

Copyright by chinadaily.com.cn. All rights reserved. None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited. 版權聲明:本網站所刊登的中國日報網英語點津內容,版權屬中國日報網所有,未經協議授權,禁止下載使用。 歡迎愿意與本網站合作的單位或個人與我們聯系。

電話:8610-84883645

傳真:8610-84883500

Email: languagetips@chinadaily.com.cn

主站蜘蛛池模板: 成年人在线免费观看视频网站 | 美女张开大腿让男人桶 | 成人午夜毛片 | 免费看成人频视在线视频 | 欧美激情亚洲一区中文字幕 | 欧美一级免费在线观看 | 在线a人片免费观看国产 | 国产一级aa大片毛片 | 免费一级毛片麻豆精品 | 日韩在线免费视频 | 久久免费激情视频 | 国产一线视频在线观看高清 | 日本强不卡在线观看 | 毛片一级做a爰片性色 | 911精品国产亚洲日本美国韩国 | 九草在线免费观看 | 亚洲欧美日韩精品久久 | 一区二区三区亚洲 | 手机看片日韩日韩国产在线看 | 999热精品这里在线观看 | 久久受www免费人成看片 | 久久亚洲国产的中文 | 欧美精品久久一区二区三区 | 亚洲一区视频在线播放 | 亚洲欧美综合一区二区三区四区 | 国产黄色自拍视频 | 亚洲国产欧美国产综合一区 | 韩国日本三级在线观看 | 操爽视频 | 99久久精品国产自免费 | 一级片网址 | 国产精品国三级国产aⅴ | 91视频社区| 免费一级毛片在级播放 | 韩国porno xxxx | 在线观看亚洲 | 免费播放欧美毛片欧美aaaaa | avove旗袍丝袜高跟啪啪 | 黄色片日本人 | 中国一级片免费看 | 国产精品国产三级国产普通 |