胺,氨基乙烷[C2H5NH2]

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute. As Valentines day approaches, remember, its the thought that counts. Just ask a decorated cricket. Because according to a study published in the January

发表于:2018-12-24 / 阅读(59) / 评论(0) 分类 Scientific American(一)月

Protamine sulfate is a drug that reverses the anticoagulant effects of liver compounds such as heparin. Protamine is extracted from the sperm of salmon and other species of fish, and then made into a protamine sulfate injection which is a necessary d

发表于:2019-01-19 / 阅读(66) / 评论(0) 分类 世界各地新闻集锦

On its website, a history of the company makes no mention of leador indeed of Thomas Midgleybut simply refers to the original product as containing a certain combination of chemicals. 在它的网站上,公司的历史没有提及铅──也没有提

发表于:2019-02-17 / 阅读(53) / 评论(0) 分类 万物简史

By counting back through these layers and measuring the amount of lead in each, he could work out global lead concentrations at any time for hundreds, or even thousands, of years. The notion became the foundation of ice core studies, on which much mo

发表于:2019-02-17 / 阅读(59) / 评论(0) 分类 万物简史

Lead is a neurotoxin. Get too much of it and you can irreparably damage the brain and central nervous system. Among the many symptoms associated with overexposure are blindness, insomnia, kidney failure, hearing loss, cancer, palsies, and convulsions

发表于:2019-02-17 / 阅读(53) / 评论(0) 分类 万物简史

If you were going to a restaurant and wanted a healthier option, 如果你去饭店,你想吃得健康一点, which would you choose, grilled or fried chicken? 你会选择哪种食品呢,烤鸡还是炸鸡? Now most people would answer grill

发表于:2019-02-21 / 阅读(68) / 评论(0) 分类 TED演讲教育篇