科學60秒:含碳納米管——讓飛機更安全
來源：滬江聽寫酷
2011-07-29 10:00
Airplane manufacturers have been changing over from aluminum to advanced composite materials. These lighter, stronger composites are made of fibers of carbon or glass ____1____ a second material, often plastic.
One advantage is that composite-based planes use significantly less fuel. But there’s an important disadvantage. When aluminum is hit, you can see a dent. Composites, though, ____2____ to the original shape, which could hide internal damage.
One technique to test composite material ____3____heat transfer. Inspectors place large heaters next to a section of the plane. Any cracks will alter the flow of heat, and these changes can be picked up with a heat-sensitive camera. But this involves ____4____and expensive equipment.
Now M.I.T. researchers have designed a new system. All you need is carbon nanotubes included in the composite, because nanotubes will heat up in response to a small electric current. This can be produced with a handheld device. Any internal deformations will still change the heat flow, which can be picked up by the ____5____ camera. The research was published in the journal Nanotechnology.
This technique offers the ability to detect very small cracks—which could help keep passengers safer in the skies.
【視聽版科學小組榮譽出品】
One advantage is that composite-based planes use significantly less fuel. But there’s an important disadvantage. When aluminum is hit, you can see a dent. Composites, though, ____2____ to the original shape, which could hide internal damage.
One technique to test composite material ____3____heat transfer. Inspectors place large heaters next to a section of the plane. Any cracks will alter the flow of heat, and these changes can be picked up with a heat-sensitive camera. But this involves ____4____and expensive equipment.
Now M.I.T. researchers have designed a new system. All you need is carbon nanotubes included in the composite, because nanotubes will heat up in response to a small electric current. This can be produced with a handheld device. Any internal deformations will still change the heat flow, which can be picked up by the ____5____ camera. The research was published in the journal Nanotechnology.
This technique offers the ability to detect very small cracks—which could help keep passengers safer in the skies.
【視聽版科學小組榮譽出品】
embedded in spring back takes advantage of bulky thermal
飛機制造經歷了從鋁材到復合材料的變革。將碳纖或玻璃纖維鑲嵌到第二種材料（通常都是塑料）中去，就得到了更輕更結實的復合材料。 用復合材料制造飛機的好處之一就是省油效果明顯。但這有個嚴重的弊端。當鋁受熱時會凹陷進去，但復合材料卻會恢復原狀，這可能讓我們無法察覺飛機的內部損傷。 有一種技術利用熱傳遞來測試符合材料。檢測員在飛機部件旁放上一個巨大的加熱器，裂縫會改變熱流，而這些改變會被熱感照相機感應到。但這需要昂貴的巨型機器才能辦到。 如今，麻省理工的研究者設計了一個新型系統(tǒng)。你只需要使用復合材料中的含碳納米管，因為碳納米會在弱電流下產熱。這過程要用到設備很小，可以用手拿著。內部變型仍然會改變熱流，熱流的改變仍會被熱感照相機感應到。這次研究發(fā)現(xiàn)刊登在《納米技術》雜志上。
