[ti:Can Wood Be Stronger Than Steel?] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.12]Researchers say they have created a new super-material in the laboratory. [00:07.08]They say it is stronger, lighter and costs less than steel. [00:13.58]But the new material is not a product of high technology [00:19.35]or a metallic substance. It is wood. [00:23.84]Researchers Liangbing Hu and Teng Li [00:27.44]are with the University of Maryland in the United States. [00:32.12]By using a few chemicals, heat and pressure, [00:37.76]they have made wood three times denser and 10 times stronger. [00:44.88]Hu says that means it can compete with some of the world's strongest materials. [00:52.08]"We're interested in replacing steel and carbon fibers [00:56.40]with strong wood structures," he said. [01:00.13]The process does not require any special raw, unprocessed material. [01:08.16]Hu said that means the cost of the product will be relatively low. [01:14.36]He added, "We can start with very cheap wood, [01:18.68]and we can also start with very fancy, expensive wood. [01:23.52]But in the end, ultimately we get very similar performance." [01:29.56]The researchers are calling their product "super wood." [01:33.64]It is made by partially removing a natural polymer called lignin. [01:41.24]Hu explained that "lignin is like a binder [01:45.17]to hold all the components together in natural wood. [01:49.96]In our process, we found out to be able to densify the wood completely, [01:55.84]we have to remove some of these binders." [02:00.36]Strong chemicals are put on the wood. [02:04.04]The chemicals remove about half of its lignin. [02:08.84]Then, after being left in extreme heat and pressurized for a day, [02:14.60]the treated wood is ready. [02:17.72]The researchers say the wood is strong enough to build automobiles, [02:22.64]airplanes, wind turbines and more. [02:26.92]A report on their findings was published in the journal Nature. [02:33.20]The researchers say super-strength wood would have less of an effect [02:37.80]on the environment than the steel or other metals it could replace. [02:43.44]However, their process is not pollution-free. [02:48.28]It uses some of the same chemicals involved in making paper. [02:54.56]Researcher Teng Li says he and Hu are finding many new ways to use wood, [03:00.72]including creating batteries and see-through wood and paper. [03:06.08]"Wood has been existing on Earth more than a million years. [03:09.37]And human beings have been using wood for furniture, [03:12.19]construction for more than 10 thousand years. [03:14.60]And the more we worked on this material, we realized, [03:18.72]we have never fully exhausted the potential of this amazing material." [03:25.12]Other scientists are finding new uses for wood as well. [03:30.00]Researchers in Sweden have reported making wood-based [03:33.57]super-strong fibers for clothing and other materials. [03:39.36]I'm Jonathan Evans. [03:41.20]更多听力请访问51VOA.COM