Healing Plastic

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                            08 新型塑胶制品的应用

DATE=3-1-01
TITLE=SCIENCE REPORT- Self-Healing Plastic
BYLINE=Mario Ritter

 (Start at 59")This is the VOA Special English SCIENCE REPORT.
American scientists have developed the first material that repairs itself. The material is a form of (1) plastic that has been (2) engineered to fill breaks in its surface.
Plastics are used today in everything from (3) airplane wings to hundreds of objects found in the home. Scientists wanted to find a way to make objects made of plastic last longer. The researchers hope their new discovery can be used to make objects that are difficult or impossible to replace.
The surface of plastic objects breaks over time. Very small breaks, or (4)cracks, develop every time a plastic object is used. The researchers wanted to find out how to stop plastic from developing small cracks that grow, weaken² and destroy it. The research team at the University of Illinois at Champaign-Urbana found an answer to the problem. They found the answer in the chemical (5) structure of plastic itself.
Plastic is made of small (6) molecules³ called (7) monomers. These monomers (8)link together to form very long molecules called (9) polymers. Polymers give plastic its ability to be shaped and its strength.
The research team found a way to make plastic that contains very small (10) balloons filled with liquid. The liquid contains monomer molecules - the building material of plastic. The team then created solid plastic that contains a special chemical. This chemical is called a (11) catalyst⁴. A catalyst is a (12) substance that starts a chemical reaction.
The new plastic still cracks like common plastic. But, when it does, the monomer liquid is released⁵ and flows into the crack. The catalyst in the solid plastic then reacts with the liquid monomer. The chemical reaction between the liquid monomer and the catalyst creates polymer molecules that repair the break. The repaired plastic has seventy-five percent of the strength of (13) undamaged plastic.
The scientists say the new self-repairing plastic is not yet ready for production. But it has several possible uses. One could be in space (14) vehicles where parts cannot be repaired or replaced. Another possible use might be in bridges. And it could be used in people, to replace bone joints⁶ that have become broken or damaged. These include knees or hips⁷. The leader of the study is Scott White, a professor of engineering⁸. He says the material is able to repair itself just as the human body is able to heal¹ itself.
This VOA Special English SCIENCE REPORT was written by Mario Ritter.

(1) plastic[ 5plAstik, plB:stik ]n.塑胶, 可塑体, 塑料制品, 整形adj.塑胶的, 塑造的, 有可塑性的, 造形的, (外科)整形的
(2) engineer[ 7endVi5niE ]n.工程师, 技师, 火车司机, 轮机员, 工兵
(3) airplane[ 5ZE7plein ]n.飞机
(4) crack[ krAk ]n.裂缝, 噼啪声v.(使)破裂, 裂纹, (使)爆裂adj.最好的, 高明的
(5) structure[ 5strQktFE ]n.结构, 构造, 建筑物vt.建筑, 构成, 组织
(6) molecule[ 5mClikju:l, 5mEu- ]n.[化]分子, 些微
(7) monomer[ 5mCnEmE ]n.单体
(8) link[ liNk ]n.链环, 连结物, 火把, 链接vt.连结, 联合, 挽vi.连接起来
(9) polymer[ 5pClimE ]n.聚合体
(10) balloon[ bE5lu:n ]n.气球
(11) catalyst[ 5kAtElist ]n.催化剂
(12) substance[ 5sQbstEns ]n.物质, 实质, 主旨
(13) undamage[ 5Qn5dAmidV ]完整无损
(14) vehicle[ 5vi:ikl ]n.交通工具, 车辆, 媒介物, 传达手段

1 heal   

v.使愈合，治愈，使康复；平息(争吵等)；消除，解决(分支等)

参考例句：

• Time helped heal the old wounds.时间有助于治愈旧创伤。
• This wound will soon heal if yon keep it clean.如果你保持伤口清洁，它很快就会痊愈。

2 weaken   

v.(使)变弱，(使)虚弱

参考例句：

• You can weaken the tea by adding water.你可以加水把茶弄得淡一些。
• We never weaken our efforts in face of difficulties.我们在困难面前从不软化我们的努力。

3 molecules   

分子( molecule的名词复数 )

参考例句：

• 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。

4 catalyst   

n.催化剂，造成变化的人或事

参考例句：

• A catalyst is a substance which speeds up a chemical reaction.催化剂是一种能加速化学反应的物质。
• The workers'demand for better conditions was a catalyst for social change.工人们要求改善工作条件促进了社会变革。

5 released   

v.释放( release的过去式和过去分词 )；放开；发布；发行

参考例句：

• 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。

6 joints   

接头( joint的名词复数 )； 关节； 公共场所（尤指价格低廉的饮食和娱乐场所） （非正式）； 一块烤肉 （英式英语）

参考例句：

• Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
• Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。

7 hips   

abbr.high impact polystyrene 高冲击强度聚苯乙烯，耐冲性聚苯乙烯n.臀部( hip的名词复数 )；[建筑学]屋脊；臀围（尺寸）；臀部…的

参考例句：

• She stood with her hands on her hips. 她双手叉腰站着。
• They wiggled their hips to the sound of pop music. 他们随着流行音乐的声音摇晃着臀部。 来自《简明英汉词典》

8 engineering   

n.工程，工程学，管理，操纵

参考例句：

• The science of engineering began as soon as man learned to use tools. 人类一学会使用工具,工程科学就开始了。
• It was the first great engineering works in the world. 这是世界上第一家大型的工程工厂。