[地物] 羟基发射带

This is Scientific American's 60-Second Science. I'm Steve Mirsky. Got a minute? On June 4th we told you about iron snowflakes on Mercury. Today we have some radical news about the atmosphere of Venus. Literally, a radical is a molecule that reacts e

发表于:2018-12-24 / 阅读(48) / 评论(0) 分类 Scientific American(六)月

There is a special day to recognize the importance of the ozone layer. In 1995, the United Nations General Assembly decided September 16th is the International Day for the Preservation of the Ozone Layer. This is the date on which countries signed th

发表于:2018-12-29 / 阅读(105) / 评论(0) 分类 英语课程学习计划和讲义

Scientists have found that levels of a now-banned chemical are rising again in Earths atmosphere. The chemical is called CFC-11. It is the second most common kind of CFC, short for chlorofluorocarbon. Chlorofluorocarbons were once widely used in many

发表于:2019-01-03 / 阅读(54) / 评论(0) 分类 2018年VOA慢速英语(五)月

Erythromycin,红霉素 Azithromycin,阿奇霉素 Clarithromycin,克拉霉素 Fluoroquinolones and their derivatives (e.g. levofloxacin),多西环素(如:脱氧土霉素) Tetracyclines (e.g

发表于:2019-01-03 / 阅读(41) / 评论(0) 分类 医务英语

分集介绍:导数,商数,正弦和余弦 Derivatives.of.products.quotients.sine.cosine

发表于:2019-01-05 / 阅读(285) / 评论(0) 分类 麻省理工学院公开课:单变量微积分

I first heard about the ozone layer about twenty years ago. I was still in school. I thought it was interesting, but I didnt take it seriously. It was a bit like science fiction, I mean, how could there be a giant hole in the atmosphere? Over the yea

发表于:2019-01-21 / 阅读(66) / 评论(0) 分类 纯正英语一分钟