日韩精品久久一区二区三区_亚洲色图p_亚洲综合在线最大成人_国产中出在线观看_日韩免费_亚洲综合在线一区

 
 
 

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(chuàng)作品,除與中國日報網簽署英語點津內容授權協(xié)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(lián)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(lián)系,如產生任何問題與本網無關;本網所發(fā)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?zhí)峁┌鏅嘧C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(lián)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(xié)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(lián)系。

電話:8610-84883645

傳真:8610-84883500

Email: [email protected]

主站蜘蛛池模板: 免费观看一级毛片 | 国产在线毛片 | 亚洲一区播放 | 国产精品高潮呻吟久久av黑人 | 成人精品视频 | 久久天天躁狠狠躁夜夜躁2014 | 国产精品色在线网站 | 精品国产一区二区三区久久久蜜臀 | 青青久热| 精品久久久久久综合日本 | 美女露尿口视频 | 91精品视频免费 | 视频一区二区在线观看 | 无码无遮挡成人A片 | 国产三级在线视频 一区二区三区 | 久久这里只有精品23 | 欧美综合伊人久久 | 亚洲午夜免费视频 | 欧美第一网站 | 老司机午夜免费精品视频 | 天干天夜啪天天碰 | 国产精品久久久久久久久久日本 | 精品欧美亚洲韩国日本久久 | 美女在线视频网站 | 91网站在线观看视频 | 欧美一区二区三区免费不卡 | 免费一级毛片 | 99热热99| 男女xx00xx的视频免费观看 | 亚洲美女毛片 | 日本AAA片爽快视频 波多在线 | 激情色播 | 精品美女在线观看视频在线观看 | 91伊人久久 | 亚洲日韩色图 | 亚洲视频免费在线观看 | 亚洲精品在线第一页 | 天天干天天爱天天操 | 99久久99| 青青草99热久久 | 国产精品三级国语在线看 |