Sci-Tech

Chinas Super “Eye”to Speed up Space Rendezvous

Chinese space experts have developed the worlds most sensitive “eye” that enables the autonomous rendezvous and docking of two spacecraft– flying at a speed eight times faster than a fired bullet –more efficiently and safely. The “eye” is Chinas newly developed third-generation rendezvous and docking CCD optical imaging sensor. It will be used on Chinas second orbiting space lab Tiangong-2， the Change-5 lunar probe and the permanent manned space station， according to the China Academy of Space Technology（CAST）. China plans to launch Tiangong-2 in 2016， and send Change-5 to collect samples from the moon and return to earth around 2017. It also aims to put a permanent manned space station into service around 2022.

“Good ‘eyesight is crucial for one spacecraft tracking another for hundreds of thousands of kilometers to achieve a perfect rendezvous and docking– its like threading a needle，”said Gong Dezhu， a CAST designer who worked on the CCD optical imaging sensor. “The last 150 meters between the two spacecraft is the most critical moment. A slight deviation during docking might lead to a disaster like the one caused by Mann， the protagonist in the movie interstellar，” Gong said.

Compared with the CCD optical imaging sensor used in the docking of Tiangong-1 and the Shenzhou spacecraft， the new “eye” can see clearer under direct sunlight， which will greatly improve safety. The window period of the docking process will be twice the length， Gong said.

“And the reaction time between the ‘eye capturing the first sight of its target and recognizing it has been shortened from 10 seconds to within one second，” Gong explained.

The sensors weight and power consumption is only half that of comparable mainstream products internationally. Such“eyes” can also be used on mechanical arms， and for refueling and repairing spacecraft， as well as aerial refueling and the docking of unmanned underwater vehicles.

Beijing to Host International Applied Math Congress

The Eighth International Congress on Industrial and Applied Mathematics will be held in Beijing this August. More than 3，000 mathematicians from 70-plus countries and regions will take part in the congress， the first to be held in Asia and a developing country. The applied math event is held every four years.

“Applied mathematics has been developing fast， and the integration of mathematics and engineering technology has been a key trend，” said Gao Xiaoshan， vice head of the CAS Academy of Mathematics and Systems Science.

The congress will include more than 3，000 lectures and symposia， covering various aspects of applied mathematics as well as the latest applications from biology， medical science， economics， information， climatology， environment， finance， aerospace， manufacturing， and other fields.

The congress was initiated in 1984 by the International Council for Industrial and Applied Mathematics.

New Traction System Speeds up Chinese Bullet Trains

Chinas high-speed trains will soon use a permanent magnet synchronous motor traction system that can run at up to 500 kilometers per hour. After 11 years of research and development and with an investment of RMB 100 million， the nations independently developed traction technology is ready for commercial use.

“A 690-kw permanent magnet motor traction system designed for 500-kph high-speed trains will be produced in small quantities，”said Ding Rongjun， general manager of CRRC Corps Zhuzhou Institute and academician of the Chinese Academy of Engineering. Ding said this would make China one of the few nations to master such technology after Germany， Japan， and France.

“If everything goes well， Chinese high-speed trains will soon be equipped with a new system that is more stable and secure， and uses less energy，” said Li Yifeng， chief designer at the institute.

Compared with the alternating current asynchronous motors that are widely used on bullet trains， the new system increases power by 60 percent while motor loss decreases by 70 percent.

Chinese Biologists Find Duckweed to Tackle Water Pollution

Biologists have found a strain of duckweed that can effectively purify polluted water by removing nitrogen and phosphorus. A research team led by Zhao Hai， with the Chengdu Institute of Biology under the Chinese Academy of Sciences， identified the duckweed species from more than 800 samples collected across the world in nine years. The team has applied for a national invention patent for the duckweed system.

Duckweed， the smallest aquatic flowering plant in the world， absorbs a high level of nitric oxide and phosphide and is quite effective in dealing with heavy metal pollution， according to Zhao. After six days of duckweed treatment， wastewater passes the A-category pollutant discharge standard.

More than 70 percent of Chinas rivers and lakes are polluted and reducing aquatic nitric oxide content would go some way to addressing this， he said. Should this duckweed be planted in just one percent of Chinas lakes and ponds， it could generate 1.72 million tons of ethanol annually， worth RMB 10.3 billion. Meanwhile， it can reduce emissions of carbon dioxide by 10 million tons， which has broad prospects.