SSS 2012-04-20
时间:2018-12-24 作者:英语课 分类:Scientific American(四)月
As it ages, white paper turns distinctive 1 of yellow, but why? To find out, scientists artificially aged 2 modern paper to rebuild the changes on the molecular 3 level, the researchers in the Journal physical review of letters, for 48 days, 3 unpleached paper samples aged rapidly on reactors 4 that's simulated in different environmental conditions, the researchers then compared the artificially aged samples to the real deal, 3 pieces of paper crafted in 15 century Europe, this technique allowed them to gauge 5 the types and the months of changes going on, about 90% of the weight of old paper is cellulose, the sturdy material that makes plants so walls, but over time cellulose fibers 6 oxidase, the process modifies parts of burriest molecules 7 and turns them into what we call chromophores which absorb light, white paper is white because it reflect all colors of lights, aging paper filled with chromophores reflects wavelength 8 that makes it look yellow, the non-destructive technique used in the study couldn't inform research to preserve and even widen in ancient * art and give paper conservation a brighter outlook.
- She has a very distinctive way of walking.她走路的样子与别人很不相同。
- This bird has several distinctive features.这个鸟具有几种突出的特征。
- He had put on weight and aged a little.他胖了,也老点了。
- He is aged,but his memory is still good.他已年老,然而记忆力还好。
- The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
- For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
- The TMI nuclear facility has two reactors. 三哩岛核设施有两个反应堆。 来自英汉非文学 - 环境法 - 环境法
- The earliest production reactors necessarily used normal uranium as fuel. 最早为生产用的反应堆,必须使用普通铀作为燃料。
- Can you gauge what her reaction is likely to be?你能揣测她的反应可能是什么吗?
- It's difficult to gauge one's character.要判断一个人的品格是很困难的。
- Thesolution of collagen-PVA was wet spined with the sodium sulfate as coagulant and collagen-PVA composite fibers were prepared. 在此基础上,以硫酸钠为凝固剂,对胶原-PVA共混溶液进行湿法纺丝,制备了胶原-PVA复合纤维。
- Sympathetic fibers are distributed to all regions of the heart. 交感神经纤维分布于心脏的所有部分。
- The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
- Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里,大分子裂变为小分子。
- The authorities were unable to jam this wavelength.当局无法干扰这一波长。
- Radio One has broadcast on this wavelength for years.广播1台已经用这个波长广播多年了。