氯化物氟化物电解液

SSS 2010-12-29

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute. Beauty is only skin deep. And the beauty of shiny white teeth is even less deep. Because a new study shows that fluoride forms a thinner protective shiel

发表于:2018-12-02 / 阅读(89) / 评论(0)

Scientific American(十二)月

Dental Health

07 牙病的预防与治疗 DATE=2-27-01 TITLE=SCIENCE IN THE NEWS #2113 - (1)Dental Health BYLINE=Nancy Steinbach VOICE ONE: This is Sarah Long. VOICE TWO: And this is Bob Doughty with Science in the

发表于:2018-12-07 / 阅读(58) / 评论(0)

科技之光

VOA标准英语2010年-Coal Burning Linked to Fluoride Diseas

A cluster of villages in China's Guizhou province has been plagued by an outbreak of disease that damages teeth and bones. Now, a new study by Chinese and American researchers puts the blame on polluted coal burned in home fireplaces. In small quanti

发表于:2019-01-14 / 阅读(69) / 评论(0)

VOA标准英语2010年(十)月

科学美国人60秒 SSS 2016-1-1

Every winter some twenty million tons of salt are dumped on America's road.That sodium chloride melts the ice, so it prevents its formatin, helping to prevent accidents. But road salt has its downside. This is not very economical because salt is main

发表于:2019-01-20 / 阅读(107) / 评论(0)

2016年Scientific American(一)月

英语听力：自然百科为什么海水是咸的？

This week on Why Tell Me Why, we are finding out why the oceans are so salty. So the oceans are salty because the oceans have been around, lets say, for over five hundred million years. And over the course of time what we found out is that weve alway

发表于:2019-01-22 / 阅读(64) / 评论(0)

自然百科2009年

学个词 Learn a Word-VOA英语教学 2280-fluoride

今天我们要学的词是 fluoride. Fluoride 氟化物。The U.S. government is lowering the recommended amount of fluoride added to drinking water for the first time in more than 50 years. 美国政府50多年来首次降低饮用水建议添加的氟

发表于:2019-02-02 / 阅读(60) / 评论(0)

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air bottle with steady pressure