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
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学英语单词
acetone resin
acridophagous
alkaline-resistant paint
amphiphile
ascandroside
atomic beam frequency standard
bish-bash-bosh
booking report
booty bump
bounce the ball
built pillar
Campanumoea javanica
cepharadione
change direction protocol
cold plug
communers
contact polling
conveying device
Corynocarpaceae
crush fracture
disk anode
double-pole three-throw (dptt)
effective green time
elevated shore line
envenometh
Ewart sign
external-diameter
Extra Serious Accident
Fagerhult
fourscorer
fragaria ananassas
free index
full-cross gauze
gelada
glow conduction
gross proceeds from sales
half serious
handicappings
high-energy ignition
interbedded mineral deposit
international transaction
jig tenter
John of Leyden
keep one's nose out
lavrenti pavlovich berias
lead a woman to altar
legal instrument
leviathan yarn
liquid-springing
lloyd's foreign legislation department
lollingite
long-focus technique
lower stratosphere
machine analysis display
mahmoodi
Mongun
multilevel operation
nagashimalite
noncompensated
Nova Scotian
onchoceriasis
out of the hat
palaeopropithecids
pandur-
papilloretinitis
pernice
phonebooths
phosphohexonate
pored wood
posterior labial vein
pregenerated
press manager
private call
re-embrittlement
reference black level
resistance capacitance network
rolly oil
Saharsa
schwarzer zeolith
Scotch cloth
sedimentary particles in suspension
semi built-up type
skil
solid-solid interfaces
splots
strain energy theory
tapered foot roller
technical paper
therapeutic window
third scale-step
triangular girder
true dwarves
viscosimeter transpiration type
vt fuse
walkie
weeksman
wrench fork
young fogey
zemni
Zilavka
zoogyroscope