SSS 2011-03-28
时间：2018-12-24 作者：英语课 分类：Scientific American(三)月
This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.
Airplane manufacturers have been changing over from aluminum 1 to advanced composite materials. These lighter 2, stronger composites are made of fibers 3 of carbon or glass embedded 4 in 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 5. Composites, though, spring back to the original shape, which could hide internal damage.
One technique to test composite material takes advantage of heat transfer: inspectors 6 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 bulky and expensive equipment.
Now MIT 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 hand-held device. Any internal deformations 7 will still change the heat flow, which can be picked up by the thermal 8 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.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.
- The aluminum sheets cannot be too much thicker than 0.04 inches.铝板厚度不能超过0.04英寸。
- During the launch phase,it would ride in a protective aluminum shell.在发射阶段，它盛在一只保护的铝壳里。
- The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
- The lighter works off the car battery.引燃器利用汽车蓄电池打火。
- Thesolution of collagen-PVA was wet spined with the sodium sulfate as coagulant and collagen-PVA composite fibers were prepared. 在此基础上，以硫酸钠为凝固剂，对胶原-PVA共混溶液进行湿法纺丝，制备了胶原-PVA复合纤维。
- Sympathetic fibers are distributed to all regions of the heart. 交感神经纤维分布于心脏的所有部分。
- an operation to remove glass that was embedded in his leg 取出扎入他腿部玻璃的手术
- He has embedded his name in the minds of millions of people. 他的名字铭刻在数百万人民心中。
- I don't know how it came about but I've got a dent in the rear of my car.我不知道是怎么回事，但我的汽车后部有了一个凹痕。
- That dent is not big enough to be worth hammering out.那个凹陷不大，用不着把它锤平。
- They got into the school in the guise of inspectors. 他们假装成视察员进了学校。 来自《简明英汉词典》
- Inspectors checked that there was adequate ventilation. 检查员已检查过，通风良好。 来自《简明英汉词典》
- It would make no difference if the bar deformations were totally inelastic. 如果杆的变形完全是非弹性变形时这也就没有什么区别了。
- Such readings can reveal longer-period deformations in the earth. 这种读数可以反映地球长周期的形变。