混凝土枕的失效标准是什么?

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问题:

混凝土枕的失效标准是什么?

考点:铁路线路工初级线路工理论知识初级线路工理论知识题库
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Colleges in the US have added a new subject, “great chemistry”, to their curriculum today. “Green chemistry (53) how we can develop products that won’t (54) the environment,” explains Paul Anastas, director of Yale University’s Center for Green Chemistry and Green Engineering, opened at the beginning of this year. The American Chemical Society, (55) approves more than 600 college chemistry programs, only lists about a dozen that teach green chemistry. But that (56) is growing.
Cambridge College in Massachusetts is offering “ an introduction to green chemistry” course this gall and is offering the nation’s first bachelor’s and master’s (57) in green chemistry. The program will have classes in environmental science and even environmental (58) and policy. These subjects are not (59) taught to chemistry major.
Employers (60) the introduction of green chemistry. Businesses are increasing seeking graduates (61) backgrounds in the subject because it can help them make or save money in he development and manufacturing of products. “We need people who can not only understand their place (62) , but also understand the worldwide perspective,” said Adam Peterson, a chemical division manager at Dow Corning Corp.

A.law
B.act
C.bill
D.treaty

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塔柱对接焊缝在用超声波100%检查之后,如有可疑点,应再用()复查,按焊缝的25%进行检查。

A.磁粉探伤

B.渗透探伤

C.X射线

D.5~10倍放大镜

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下列哪项不属于电子订货方式的特点。()

A.速度快

B.可靠性好

C.准确性低

D.前期投资大,运行成本低

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在一个封闭经济中,无论储蓄来自公共还是私人,投资总等于储蓄

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应急照明电路中的软启动电路的作用是:()。

A.延缓电瓶充电

B.延长灯泡的寿命

C.延缓电瓶放电

D.加快点亮照明灯

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