VOA标准英语2009年-Nanotechnology Offers Some Solutions t（在线收听）

Tiny nanomaterials show promise in many efforts to reduce greenhouse gas emissions

Rosanne Skirble | Washington, DC 03 December 2009

Sir Lankan village shop at dusk lit by solar panels - Nanotechnology could help make solar cells more accessible, efficient and affordable

Nanoparticles are tiny. These unique materials, sometimes comprising only a few atoms or molecules, can be manipulated to make new materials with novel properties. Some are better at conducting electricity or heat. Others are lighter, harder or more durable. Nanoparticles are already inside hundreds of consumer products from bicycle parts and tennis racquets, to clothing and cosmetics.  Andrew Maynard, chief science advisor for the Emerging Nanotechnology Project at Washington's Woodrow Wilson International Center for Scholars, says nanomaterials could help reduce greenhouse gas emissions, which is a major goal of the upcoming international climate talks in Copenhagen.

Making solar cells more affordable and efficient

Maynard says nanoparticles show a lot of promise in renewable energy fields like solar power.   "One of the technologies which is being looked at is roll-to-roll technologies for solar cells, where effectively we can print the next generation of solar cells on flexible surfaces. That not only makes it very cheap, but it also means that we can use these new cells in new innovative ways."     

Lighter vehicles use less fuel

Next to China, the U.S. is the world's largest polluter. Twenty-eight percent of U.S. greenhouse gas emissions are from transportation. Maynard says nanomaterials can help reverse that trend.  "If you can make a car or an airplane which is far lighter than current ones, and yet still being stronger and safer, you can reduce the engine required to get from point A to point B. And again, nanotechnology is allowing us to do that," he says.

Nano-additives in diesel fuel have also shown to increase efficiency and reduce emissions.  Maynard says nanotechnology could also increase battery storage capacity. With an expanding electric vehicle market, rechargeable batteries would be in great demand. "And a number of companies are currently working on developing relevant batteries which are going to be far more powerful, be able to store far more energy and release that energy far faster than conventional batteries because they are being engineered," he says.

Nanotechnology could make hydrogen fuel a viable option

Maynard also says that nanotechnology could help launch hydrogen as an alternative to fossil fuels. When it burns, he says, the byproduct is water. "There are two components to this.   You've got the fuel cell, which converts the hydrogen and oxygen into electricity, but then you've got the tank that holds your hydrogen. It's the tank that holds the hydrogen, which is one of the really difficult parts at the moment. Because one of the only options that it seems is available at the moment is to compress this hydrogen to very, very high pressures and put it into a tank, which is inherently unsafe." 

Maynard says nanotechnology offers some solutions to the hydrogen fuel safety problem by creating materials that can be packed full of hydrogen, not at low temperatures and not at high pressures. "There you've got an intrinsically safe way of transporting your hydrogen around, ready to put into your fuel cell whenever you need it."

Questions remain about the safety of nanomaterials

But Maynard says, as new nanomaterials are developed, safety remains a legitimate concern. "There is still some uncertainly about the new materials and how they might spread through the environment, how they might affect environmental organisms and how they might affect humans if we are exposed to them. So there's research there that needs to be done, but certainly I don't think there are any insurmountable problems."     
   
And he believes that onnce they've established their utility and safety, nanoscale materials will eventually complement existing technologies in helping to mitigate the impact of climate change.