2. 外语
  3. Noses have their advantages. They’re cute, they’re versatile, and they’re small enough to be carried around. Which may be why th

Noses have their advantages. They’re cute, they’re versatile, and they’re small enough to be carried around. Which may be why th

admin2013-03-11  45
问题     Noses have their advantages. They’re cute, they’re versatile, and they’re small enough to be carried around. Which may be why the artificial odor detectors that engineers have been building since the 1950’s to try to mimic the olfactory(嗅觉的) abilities of our built-in sensors have taken so long to find their way to the market--and then, in most cases, have flopped(失败).
    But things are finally looking up for the electronic nose. Thanks to advances in chip technology and pattern-recognition techniques, increasingly tiny sniffers (嗅探器) are beginning to live up to their moniker (模仿者)- Today e-noses are being tested for everything from disease detection to disaster prevention, and lower-prices models are starting to come to the market including an $ 8,000 device called the Cyranose 320 being introduced this week by Cyrano Sciences of Pasadena, Calif.
    Like our proboscises(长鼻子), e-noses are only as good as their sensors, and all of them operate on oiliness(油质)--rather than to the molecule itself. Working together, the receptors can generate unique principles remarkably similar to those of a real nose. Humans detect odors with up to 650 types of receptors found on cells high up in the nasal passages, somewhere between our eyebrows. How the nose works is still something of a mystery, but it is believed that each receptor responds to a subtle characteristic of a molecule that carries odor--its peculiar shape, say, or degree of "smell prints" of a wide variety of odors, which are then parceled off to the brain and stored.
    In e-noses, chemical sensors replace the body’s cellular receptors, and microprocessors substitute for the brain. "What limits these devices is how well the sensors are doing," explains Nathan Lewis, the Caltech chemist who helped invent the sensor technology licensed by Cyrano and who has since continued his research independently. He compares the power of e-noses to the resolution of computer monitors: "Are you seeing the world in eight shades of gray or in 16 million colors?"
It can be inferred from the passage that ______.
选项 A、scientists have discovered the working mechanism of the nose
B、humans detect odors with a large number of receptors responsive to the odorous molecules themselves
C、the receptors integrate various responses to the characteristics of an odor and store them in the brain
D、e-noses operate on principles totally different from those of a real nose
答案C
解析 推论题。该题问及人鼻的嗅觉原理。根据文章第三段的最后一句“How the nose works is still something of a mystery，but it is believed that．．．which are then parceled off to the brain and stored．” (鼻子的工作原理仍然是个谜：所知甚少，但是大家认为，每个接收器对具有特定形状的分子的微妙特点作出反应，或者是对众多气味的“气味痕”的程度作出反应，而这些印痕则被汇集起来，传送到大脑存贮。)因此可推出选项C为正确答案。
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