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As it ages, white paper turns distinctive of yellow, but why? To find out, scientists artificially aged modern paper to rebuild the changes on the molecular level, the researchers in the Journal physical review of letters, for 48 days, 3 unpleached p
Scientific American(四)月
As it ages white paper turns a distinctive yellow. But why? To find out, scientists artificially aged modern paper to reveal the changes on the molecular level. The research is in the Journal Physical Review Letters. For 48 days, three unbleached pap
Scientific American(四)月
This is Scientific American 60 second Science I am Sophie Bushwick, got a minute? As it ages, white paper turns a distinctive yellow. But why? To find out, scientists artificially aged modern paper to reveal the changes on the molecular level. The re
Scientific American(四)月
Tyler Environmental Prize Winners: Pollution's Effects Far-Reaching Nearly half of the worlds people use biomass fuels such as wood or dried dung to cook their food, and many cook indoors. Professor Kirk Smith of the University of California, Berkele
VOA标准英语2012年(五月)
Wang Yifang, from the Institute of High Energy Physics of the Chinese Academy of Sciences, attended the award ceremony of the 2016 Breakthrough Prize in Fundamental Physics at the NASA Ames Research Centre. He is the director of the team behind China
2015CRI中国国际广播电台
By Bill Rodgers Washington, D.C. 15 December 2006 watch Talks Preview Six-party talks on North Korea's nuclear program officially open Monday in Beijing but expectations are reported to be low that a breakthrough can be achieved. The talks -- which
2006年VOA标准英语（十二月）