[雅思阅读冲刺模拟试题]雅思阅读班.docx
《[雅思阅读冲刺模拟试题]雅思阅读班.docx》由会员分享,可在线阅读,更多相关《[雅思阅读冲刺模拟试题]雅思阅读班.docx(7页珍藏版)》请在淘文阁 - 分享文档赚钱的网站上搜索。
1、雅思阅读冲刺模拟试题雅思阅读班雅思网权威发布雅思阅读冲刺模拟试题,更多雅思阅读冲刺模拟试题相关信息请访问雅思索试(IELTS)网。上一次的雅思索试已经结束,下一次的雅思索试还会远吗?为了帮助大家在雅思索试中取得好成果,下面就是大范文网为大家收集整理的雅思阅读冲刺模拟试题,供大家参考。更多雅思报名官网的最新消息,最专业的雅思备考资料,请关注大范文网。Rogue theory of smell gets a boost1. A controversial theory of how we smell, which claims that our fine sense of odour depend
2、s on quantum mechanics, has been given the thumbs up by a team of physicists.2. Calculations by researchers at University College London (UCL) show that the idea that we smell odour molecules by sensing their molecular vibrations makes sense in terms of the physics involved.3. Thats still some way f
3、rom proving that the theory, proposed in the mid-1990s by biophysicist Luca Turin, is correct. But it should make other scientists take the idea more seriously.4. “This is a big step forward,” says Turin, who has now set up his own perfume company Flexitral in Virginia. He says that since he publish
4、ed his theory, “it has been ignored rather than criticized.”5. Most scientists have assumed that our sense of smell depends on receptors in the nose detecting the shape of incoming molecules, which triggers a signal to the brain. This molecular lock and key process is thought to lie behind a wide ra
5、nge of the bodys detection systems: it is how some parts of the immune system recognise invaders, for example, and how the tongue recognizes some tastes.6. But Turin argued that smell doesnt seem to fit this picture very well. Molecules that look almost identical can smell very different such as alc
6、ohols, which smell like spirits, and thiols, which smell like rotten eggs. And molecules with very different structures can smell similar. Most strikingly, some molecules can smell different to animals, if not necessarily to humans simply because they contain different isotopes (atoms that are chemi
7、cally identical but have a different mass)。7. Turins explanation for these smelly facts invokes the idea that the smell signal in olfactory receptor proteins is triggered not by an odour molecules shape, but by its vibrations, which can enourage an electron to jump between two parts of the receptor
8、in a quantum-mechanical process called tunnelling. This electron movement could initiate the smell signal being sent to the brain.8. This would explain why isotopes can smell different: their vibration frequencies are changed if the atoms are heavier. Turins mechanism, says Marshall Stoneham of the
9、UCL team, is more like swipe-card identification than a key fitting a lock.9. Vibration-assisted electron tunnelling can undoubtedly occur it is used in an experimental technique for measuring molecular vibrations. “The question is whether this is possible in the nose,” says Stonehams colleague, And
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 雅思阅读冲刺模拟试题 雅思 阅读 冲刺 模拟 试题
限制150内