[电子] 磷砷化铟光电阴极

The little splints of wood which we call matches are made out of deal or pine wood which has been soaked in melted paraffin wax to make it burn more easily. 这种被我们称之为火柴的薄木片由欧洲赤松(松树)制成, 在液体的石蜡

发表于:2018-12-18 / 阅读(38) / 评论(0) 分类 英国学生科学读本

This is Scientific American's 60-Second Science, I'm Christopher Intagliata. Got a minute? Life on earth requires six basic ingredientscarbon, hydrogen, nitrogen, oxygen, sulfur and phosphorus. Those six elements are the building blocks for DNA and R

发表于:2019-01-08 / 阅读(60) / 评论(0) 分类 Scientific American(十二)月

This is the VOA Special English Agriculture Report. Hogs at an Ohio farm Research shows that waste from pigs that are fed a special kind of corn may help a farmer's crops. And it also may help the environment. Any farmer who raises swine knows that

发表于:2019-01-11 / 阅读(62) / 评论(0) 分类 VOA慢速英语2008年(八)月

Tests Show Levels of Arsenic in US Rice Two hundred different types of rice and rice products tested by both the non-profit research group, Consumer Reports, and the U.S. Food and Drug Administration [FDA], contained varying levels of different forms

发表于:2019-01-13 / 阅读(55) / 评论(0) 分类 VOA标准英语2012年(九月)

The commercial potential for the stuffwhich soon became known as phosphorus, from Greek and Latin roots meaning light bearingwas not lost on eager businesspeople, but the difficulties of manufacture made it too costly to exploit. An ounce of phosphor

发表于:2019-01-29 / 阅读(51) / 评论(0) 分类 万物简史

Matches Striking matches, on this Moment of Science. Have you ever had a problem getting a match to light? If so, you might be using the wrong type of match. There are actually two different types of matches: safety matches and strike-anywhere matche

发表于:2019-02-26 / 阅读(60) / 评论(0) 分类 英语听力文摘 English Digest