Broken rubber bands and flat tires requi

题型:阅读理解

问题:

Broken rubber bands and flat tires requiring replacement could soon be a thing of the past.

French researchers have developed a new kind of rubber that can repair itself when broken.The new rubber is made from widely available materials including vegetable oil and a common industrial chemical.All the materials are considered safe to the environment and can be easily reused.

The best part is that the new rubber can be repaired and used again and again without losing its strength or ability or stretch.When cut, the rubber can be made new again, simply by pressing the two broken ends back together.

The product can be repaired at room temperature, around twenty degrees Centigrade;other self-healing materials require higher temperatures for repair.

Traditionally, rubber substances are made from huge molecules(分子)connected by strong chemical links, or bonds.The new rubber is made of smaller molecules.The molecules are linked together using hydrogen bonds.When connected in this way, the molecules act like one long molecule, forming what is called supramolecular networks(超分子网).When the rubber is cut, the molecules attempt to connect with whatever molecule is near them.When pressed together, the molecules are able to repair themselves at the molecular level, making the repaired rubber like new.

However, time is an important element in the process.If the broken ends are not brought together quickly, a repair is not possible.This is because molecules will form bonds with molecules on their own side.The inventors say the surfaces of the rubber can be repaired within a week of being separated.

The rubber is the creation of scientists at the Industrial Physics and Chemistry Higher Education Institution in Paris.The organization is part of France’s National Center for Scientific Research.The new material is described in greater detail in the research publication Nature.

小题1:According to the introduction, which of the following is NOT the advantage of the new rubber?

A.It can be made as easily as common rubber.

B.It is environmentally-friendly.

C.It can repair itself at room temperature.

D.It is made of smaller molecules.小题2:What does the 5th paragraph mainly tell us?

A.Why the new rubber is unique.

B.Why the new rubber can repair itself.

C.The new rubber is made from huge molecules.

D.The new rubber is different from the common rubber.小题3:If we want to know more about the technology of this kind of new rubber, where can we get the information?

A.In the researchers’ diary.

B.In a guide book.

C.In a research magazine.

D.In a newspaper.

考点:科教类阅读
题型:阅读理解

社区工作方法认为解决问题的责任不应完全放在个人身上,政府、社区均有责任提供资源,社区工作较多涉及社会政策分析和社会制度的改变,注重资源和权力分配时公平,这体现了社区工作()的特点。

A.富有批判和反思精神

B.分析问题的视角更加趋于结构取向

C.介入问题的层面更为宏观

D.具有政治性

题型:阅读理解

根据提示补写名句或填写课文原句。

差之毫厘,__________________________________。

问渠哪得清如许,____________________________。

乱入池中看不见,__________________________。

______________________________,寒光照铁衣。

已是悬崖百丈冰,___________________________。

江山如此多娇,______________________________。

题型:阅读理解

当医务人员的利益与医学界、服务对象以及整个社会等利益发生冲突而不能两全的时候,医务人员能够无私利他、自我牺牲而决不损人利己,使自己的无私利他、自我牺牲行为之和接近等于他与医学界、服务对象以及整个社会等利益发生冲突的行为之和,甚至在重大冲突时能够牺牲生命这种医德境界是()

A.最高境界

B.基本境界

C.最低境界

D.不道德境界

题型:阅读理解

不考虑药物剂量,下列反映了药物能够产生的最大效应的名词是()

A.药物效价强度

B.最大效能

C.受体作用机制

D.治疗指数

E.治疗窗

题型:阅读理解

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