时间:2019-01-08 作者:英语课 分类:Scientific American(四)月


英语课

 This is Scientific American 60 second Science I am Sophie Bushwick, got a minute?


 
As it ages, white paper turns a distinctive 1 yellow. But why? To find out, scientists artificially aged 2 modern paper to reveal the changes on the molecular 3 level. The research is in the journalPhysical Review Letters. 
 
For 48 days, three unbleached paper samples aged rapidly in reactors 4 that simulated different environmental conditions. The researchers then compared the artificially aged samples to the real deal: three pieces of paper crafted in 15th-century Europe. This technique allowed them to gauge 5 the types and amounts of changes going on.
 
About 90 percent of the weight of old paper is cellulose, the sturdy material that makes up plant cell walls. But over time cellulose fibers 6 oxidize. The process modifies parts of various molecules 7 and turns them into what are called chromophores, which absorb light.
 
White paper is white because it reflects all colors of light. Aging paper filled with chromophores reflects wavelengths 8 that make it look yellow. The nondestructive technique used in this study could inform research to preserve and even whiten ancient texts and art. And give paper conservation a brighter outlook.
 
Thanks for the minute for Scientific Americans 60 second Science I am Sophie Bushwick~

adj.特别的,有特色的,与众不同的
  • 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。
adj.年老的,陈年的
  • 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。
adj.分子的;克分子的
  • 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。
起反应的人( reactor的名词复数 ); 反应装置; 原子炉; 核反应堆
  • 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。
v.精确计量;估计;n.标准度量;计量器
  • 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。
光纤( fiber的名词复数 ); (织物的)质地; 纤维,纤维物质
  • 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。
分子( molecule的名词复数 )
  • 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。
n.波长( wavelength的名词复数 );具有相同的/不同的思路;合拍;不合拍
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话,因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
标签: sss 托福素材
学英语单词
.jpeg
accelerated application valve portion
acromial network
affiliating
alarm window
any old thing
asynchronous gyro motor
asynchronous transfer
ballistic laser holographic system
big amount
bobbin support bolt
bromononane
bypass capacitors
canalboat
chaetomium gangligerum
climate engineering
clitocybe dealbatas
coastal industry
coaxial termination
crabwisest
cross rafter
cull-tie
cyclic-inscriptable
derats
detecton
dichlorodimethylhydantoin
DILFs
direct (out-of-pocket) expenses
Discount Note
dryosaurids
duboy's bed load equation
dyf-
ecosystem type
exfoliant
file detail
forward multiple
fracture by crushing off
frim fram
given horse power
gospellers
haddam
havelis
high bars
high speed vertical miller
Hokinson, Helen
hydrothermal vent community
immediate device control block
immunostainer
information-theories
iridomalacia
isoalloxazine
local pressure gradient
local-governments
Metapan
MHHW
Mihla
naifer
neckweed
nickel-iron core
nodi lymphatici bronchopulmonales
non contractual liability
non-uniform rotor blade
over square
over the mark
palm push fit
paralecanium expansum expansum
paulingite
positive infinite product
postscripts
Power-efficiency
privilege of parliament
productive energy of feed
pulp magazine
pulseconverter
reexhumations
regio palpebralis superior
rhacomitrium dicarpum broth
sachemship
Salamīyah
save one's carcass
scleroma
scrawl
self-assembling
shipbuilder's computing center
social-development
soil erosion prediction model
spinnah
steel-cored aluminum cable
straight muscle of abdomen
symmetrical minor
terzic
theory of categories
thermal measurement
Thornton Dale
Turkey opium
tuzzle
venae scrotales
Vichy water
war horse
waspless
widowhoods
will ye , nill I