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  47
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?"
According to the passage, more and more tiny e-noses are meeting the requirements of human noses because of ______.
选项 A、improvements in chip technology and pattern-recognition techniques
B、disease detection and disaster prevention
C、expensive prices and prompt introduction of the models
D、improvements in the olfactory abilities of our built-in sensors
答案A
解析 细节理解题。该题问“越来越多的微小的电子鼻达到人鼻的要求”的原因是什么。根据文章第二段第二句话“Thanks to advances in chip technology and pattern-recognition techniques…”(由于晶片技术和图形识别技术方面的进步)，可断定A项为正确答案。
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大学英语四级

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