针对铁-碳合金回答下列问题:已知727℃时,碳在奥氏体中的溶解度为wC=0.77%,

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问题:

针对铁-碳合金回答下列问题:

已知727℃时,碳在奥氏体中的溶解度为wC=0.77%,而在铁素体中的极限溶解度仅为wC=0.0218%。请解释二者差别如此明显的原因。

考点:普通考研08工学西安交通大学硕士材料科学基础真题2008年
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阅读理解。

     BEIJING (AFP)-Archaeologists in China have uncovered more than 3 000 dinosaur footprints, state media

reported, in an area said to be the world's largest grouping of fossilised bones belonging to the ancient animals. 

     The footprints, believed to be more than 100 million years old, were discovered after a three-month

excavation (发掘, 出土) at a gully in Zhucheng in the eastern province of Shandong, the Xinhua news agency

reported.

     The footprints range from lo to 80 centimetres (4 to 32 inches) in length, and belonged to at least six

different kinds of dinosaurs, including tyrannosaurs, the report said Saturday.

     Wang Haijun, a senior engineer at the Chinese Academy of Sciences, said the footprints faced the same

direct.ion, Xinhua said.

     This indicated a possible migration or a panic escape by plant-eating dinosaurs after an attack by predators

(食肉动物), Wang added.

     Archaeologists have found dinosaur fossils at some 30 sites in Zhucheng, known as "dinosaur city". The

region has seen two major digs since 1964, and experts say the discovery of so many dinosaurs in such a

dense area could provide clues on how the animals became extinct millions of years ago.

     Plans are being made to set up a fossil park in the area.

1. We can infer from the text that _____. [ ]

A. most of the footprints are more than 32 centimeters long

B. the footprints found belong to some predators

C. the dinosaurs were runmng in all directions because of an attack

D. the area is considered to be a perfect tour source

2. Which statement below is true according to the passage above? [ ]

A. The number of the footprints found is more than 3 000.

B. The dinosaurs may live in an age 10 000 000 years ago.

C. The discovery of fossils may open a new age.

D. Archeologists still wish to find some more fossils.

3. The passage may be picked out from _____. [ ]

A. a magazine

B. a science book

C. a newspaper

D. a students' textbook

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同一帐户在重复登录统一权限平台错误前提下,会出现什么情况()

A、当前帐户会被锁定一段时间

B、仍能继续登录

C、该账户不能再登录统一权限平台

D、当前账户会被永久锁定

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中世纪可以分为下面哪两个时期()

A、上中世纪;下中世纪

B、前中世纪;后中世纪

C、南中世纪;北中世纪

D、上中世纪;中中世纪

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某女,19岁。患者一年前开始出现进食量增加,有时一餐可食一斤多米饭,外加肉食、蔬菜,一直要吃到腹胀或呕吐出来为止。自述吃东西时可以缓解情绪的紧张,但又非常担心发胖,所以经常自己催吐或者吃泻药以防止营养过剩带来的肥胖,发展至后来,患者大量进食后可以随意将胃内容物呕吐出来。其余未见明显精神异常。

对患者的治疗不恰当的是()

A.纠正水电解质紊乱

B.SSRIs

C.氟哌啶醇

D.心理治疗

E.氯氮平

题型:问答题

线路动态检查时,速度大于160km/h区段,高低的波长在30m以上的长波不平顺,当轨道检查车检查其高低幅值达到()时,应及时处理。

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