VOA常速英语2008年-Scientists Make Fabric That Generates Electrici

Scientists in the United States say they have developed fabrics² that can generate electricity.  Researchers say they have harvested enough electricity to power small electronic devices such as an mp3 player, and they say the work has potential military and aerospace³ applications.  VOA's Jessica Berman has more.

Researchers at the Georgia Institute of Technology are making energy-scavenging cloth, which has the potential to convert low-frequency vibrations⁴ into electricity.

The so-called nano-generator fabric¹ contains microscopic⁵, conductive wires woven into the material. 

The cloth, which can be used to make shirts, curtains and canvas, creates small electrical charges with the slightest movement.  The charges can be harvested into useable energy, according to materials-scientist Zhong Lin Wang.

"This particular work is about how do we develop a new methodology, new technology, that can harness from wind blowing, your body movement, this kind of mechanical, low frequency energy," he said.

Wang and the research team built a microfiber-nanowire system that they describe in the journal Nature. 

The system involves weaving nanowires grown from zinc⁶ oxide⁷ crystals, which are about one-thousandth of a hair width each, in an out of the fibers⁸ of the fabric.  Wang says the nanostructure inside the cloth looks like the bristles⁹ of two baby bottle brushes.

He says electricity is generated when the wires rub together with even the most miniscule motion, potentially harvesting energy from such mundane¹⁰ disturbances¹¹ as heartbeats and footsteps.

"Each wire generates a small [amount of] energy.  We have millions of billions of this one [wires].  When they add up, they can be appreciably¹² large," he noted¹³.

Wang says the nanogenerator can put out 80 milliwatts per square meter of fabric, enough to power small electronic devices such as an mp3 player. 

But he envisions bigger and broader applications for the microfiber-nanowire system, including powering communication devices for soldiers in remote areas and pressure sensing devices on the outside of aircraft.

"The other application can be, for example, if you have a tent and when the wind blows, and then the tent can generate electricity and then you could possibly power some of these small devices," he added.

In addition to figuring out how to scale up their effort, Wang and colleagues have another big challenge to iron out, how to launder¹⁴ nano fabrics.  It turns out that zinc oxide shirts do not do well when exposed to water.