[GMAT机经]20124阅读机经2-智课教育.pdfVIP

智 课 网 G M A T 备 考 资料 [GMAT机经]20124阅读机经2-智课教育 2.咖啡芳香的色谱研究 V1：by nicole0773 是关于科学家研发一个analyze coffee bean aroma的仪器。说原 来的仪器有各种drawback。这种新仪器可以通过喷射一种叫m的物质 来让不同的aroma显示出不同的color pattern，从而帮助coffee grower分析咖啡。 V2：by cappuccinolibr 检测 coffee aroma 的新方法 很多专业词汇。。凭印象记得 先说了两种旧方法 然后说 有一种electronic nose 说这种nose和前两个方法的drawback 一样。 然后才进入正题说新方法 新的方法是什么用 含有dye pigment 什么的一种什么。LZ实在记不得了 反正说了一段这种新方法的原理。 。。然后说这种新方法的缺点是没办法确定coffee含的到底是哪种aro ma。 V3：by happyamy 讲咖啡豆的。第一段说咖啡的成分很难分析，和原因。第二段是说 有一个方法，就像给血液标记一样，可以标记咖啡的不同成分。好像还 有一段评论性的东西。 V4：by perfectwen 第一篇是scientist发明检测咖啡aroma的新方法，貌似很多人知道 ，不过楼主是第一次遇见 Q1：问题：为什么咖啡成分那么难鉴定? Q2：问和血液标记的相似处是什么? 考古(经狗主确认，自黄色部分开始，以及后面几段的相似性较高) ： Is that Folgers coffee in your cup or Maxwell House? Now you no longer have to rely on your nose to tell. Researchers have developed an analyzer that can distinguish between 10 commercial brands of coffee and can even tell apart coffee beans roasted at various temperatures for different times. The advance could help growers determine within minutes whether a particular batch of coffee is just as good as the previous one or whether its undrinkable. Researchers have been trying for years to come up with a simple way to analyze coffee. But its no easy task. The challenge is that the aroma of roasted coffee beans consists of more than 1000 compounds that change with roasting temperatures and time. Traditional methods of chemical analysis like gas chromatography combined with mass spectrometry generally have difficulty distinguishing between compounds that are very similar to one another. And electronic noses, an array of dyes, and other sensors that change color or chemical properties when they react with certain molecules suffer from the same drawback. Over the past decade, chemist Kenneth Suslick and colleagues at the University of Illinois, Urbana-Champaign, have refined the electronic nose approach. In the new study, they used dyes that interact strongly with other chemicals, making them more specific. They then put drops of 3