时间:2019-01-16 作者:英语课 分类:农业与发展


英语课

DEVELOPMENT REPORT - Long-Life Concrete Bridges
By Jill Moss 1


Broadcast: Monday, June 07, 2004


This is Robert Cohen with the VOA Special English Development Report.


Each year, road accidents kill a million people and injure millions more. The economic costs are greatest for developing countries. Earlier this year, the United Nations called for a campaign to improve road safety.


 
Graphic 2 Image
One way to avoid accidents is better driving. Another is better roads and bridges. Engineers in the United States have designed ten new concrete mixtures that they think could make bridges last longer.


Professor Paul Tikalsky leads the experiments by a team at Pennsylvania State University. He says bridges made of concrete now last about twenty-five to thirty-five years. But he says the new mixtures might extend 3 that to seventy-five or even one-hundred years.


Concrete is made of stone, sand, water and cement 4. The materials in the cement hold the concrete together. Ancient Romans built with concrete. Yet strengthened concrete bridges did not appear until the late eighteen-hundreds. People keep looking for new ways to improve concrete. Professor Tikalsky says it is one of the most complex of all chemical systems.


The new mixtures designed by his team contain industrial waste products. He says these make the concrete better able to resist damage from water and salt over time. One of the products is fly ash. This is released 5 into the air as pollution when coal is burned.


Professor Tikalsky says particles 6 of fly ash are almost exactly the same size and chemical structure as Portland cement. This is the most costly 7 material in concrete. So using fly ash to replace some of it would save money.


Over the next two years, engineers will study ten bridges in Pennsylvania. These were built from the different cement mixtures designed by Professor Tikalsky's team. He says longer-lasting bridges could save the state more than thirty-five-million dollars a year. And he says the materials would be environmentally friendly.


The federal 8 government is paying for part of the research. Engineers anywhere can use the technology. Professor Tikalsky says some of the ideas have already been put to use in China, the Philippines and other countries.


You can find more about this research on the Pennsylvania State University Web site. The address is www.psu.edu. Again, the site is www.psu.edu.


This VOA Special English Development Report was written by Jill Moss. This is Robert Cohen.



n.苔,藓,地衣
  • Moss grows on a rock.苔藓生在石头上。
  • He was found asleep on a pillow of leaves and moss.有人看见他枕着树叶和苔藓睡着了。
adj.生动的,形象的,绘画的,文字的,图表的
  • The book gave a graphic description of the war.这本书生动地描述了战争的情况。
  • Distinguish important text items in lists with graphic icons.用图标来区分重要的文本项。
v.伸开;展开,伸展;扩大;加大
  • Can you extend your visit for a few days more?你能把你的访问再延长几天吗?
  • The examinations extend over two weeks.考试持续两个星期。
n.水泥;胶结材料;vt.粘结;巩固
  • We need 100 tons of cement at most for this project.这项工程满打满算有一百吨水泥就足够了。
  • Let's cement the parts together.咱们来把这些部件粘接在一起吧。
v.释放( release的过去式和过去分词 );放开;发布;发行
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • With hindsight it is easy to say they should not have released him. 事后才说他们本不应该释放他,这倒容易。
微粒( particle的名词复数 ); 颗粒; 极少量; 小品词
  • These small particles agglomerate together to form larger clusters. 这些颗粒聚结形成较大的团。
  • The nucleus of an atom consists of neutrons, protons and other particles. 原子核由中子、质子和其他粒子构成。
adj.昂贵的,价值高的,豪华的
  • It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
  • This dictionary is very useful,only it is a bit costly.这本词典很有用,左不过贵了些。
adj.联盟的;联邦的;(美国)联邦政府的
  • Switzerland is a federal republic.瑞士是一个联邦共和国。
  • The schools are screaming for federal aid.那些学校强烈要求联邦政府的援助。
学英语单词
abstract syntax notation
aeropulverize
aspires
auri-
avendano
bactericera miyatakeiana
bescot
Bismarck Arch.
blackened fish
BRC (below-regulatory-concern)
bufogin
bunny slopes
bursae intratendinea olecrani
bursts forth
Carex alba
Charlie Foxtrot
complex Young's modulus
Cordaianthus
cumulative mark on
device group
diaphragm pulsator
digital locker
disproportionate dwarfism
don't touch that dial
doncha
drive ... up the wall
durands
ecological terrorist
ellerby
embracer
enjoining
evasible
exuviates
fixed to floating point conversion
Foss, River
G-man
generating gear shaper
Glossodoris
Glucodiazine
glycolytic
guilty tools
hole drilling
innerduces
International Seabed Authority
iredalea exilis
it snows
klg
layd
linen papers
liquid brush rectifier
locating piece
low-volume low-pressure weed sprayer
married up
material wave
Megarhinus
meure
miascite (miaskit)
midcoursetrajectory
mistarget
mixed audio
moazagotl cloud
Munam-ni
neglect of economic performance
neodymium-doped lanthanum beryllate
new-better-than-used in expectation (nbue)
normal delay
not give a fuck
oil inlet pipe
ordinary staff
Ortodrinex
Petrocosmea grandiflora
Philiptschenko's gland
photo-mechanics
planned repair system
PMDS
polychlorobiphenyl
Purchena
radar target designation (rtd) control
Reactive Brilliant Red M-8B
recent infarct
rectifier disk
Rybinskiy Rayon
Sanicula rubriflora
schollers
servomechanistic
ship's inertial navigation system
small-scalest
sorcin
sowell
St-Léon
staphylococcic actinophytosis
Stepanshchino
stock reel
symmetrical cutting
tithis
tripodian
Trondhjem
turbulent zone
ultranationalism
Versenid
vertical accountability
weak charge