单词：up-converting laser
单词：up-converting laser 相关文章
By Carol Pearson Washington 30 April 2008 Ten years ago, the U.S. Food and Drug Administration approved LASIK, eye surgery with a laser that enables people to see without glasses. But about five percent of LASIK procedures fail, and those patients ca
VOA常速英语2008年（四月）
Converting to Another Religion Debbie: Okay, Im off. Ill be back around eight oclock. Marcelo: Hey, where are you going in such a hurry? Debbie: Im going to my religious education class. Marcelo: Religious education class? Whats that about? Debbie: W
2014年ESL之日常生活
Imagine a world where sunlight can be captured to produce electricity anywhere, on any surface. The makers of thin-film flexible solar cells imagine that world too. But a big problem has been the amount of silicon needed to harvest a little sunshine.
Scientific American(二)月
The nineteenth century held one last great surprise for chemists. It began in 1896 when Henri Becquerel in Paris carelessly left a packet of uranium salts on a wrapped photographic plate in a drawer. When he took theplate out some time later, he was
万物简史
By Paul Sisco Washington 14 November 2007 At the McDonald Observatory in western Texas, a unique space program has been quietly underway for more than 30 years. It is called the Lunar Laser Ranging Program. VOA's Paul Sisco has more. Research scienti
VOA常速英语2007年（十一月）
By Elizabeth Carlassare. Todays topic is what to do if you want to convert to a Roth IRA, but can't. A Roth IRA is a great way to save for retirement if youre eligible to contribute. With a Roth IRA, you contribute after-tax money, but your earnings
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