题目内容
有效氧化钙与氧化镁含量是判定石灰质量的主要指标。 ()
查看答案
搜索结果不匹配？点我反馈
更多问题
In the process described by the woman, why is the c0al burned？
路基填土过程中，填土的含水量应控制在最佳含水量±2%以内。 ()
听力原文：W: Hi, Jim. What are you doing？
M: Oh. Hi, Linda. I'm working on a report on energy sources for my environmental science class. But I'm having trouble finding enough information.
W: You know, we were talking about sources of fuel in my class today.
M: Yeah？
W: Prof. Collins. He's an authority on energy sources. He was telling us about a new way of getting fuel oil from coal.
M: I didn't know that was possible.
W: He said something about coal being set on fire and blasted with a mixture of steam and oxygen. This process produces a gas made up of hydrogen and carbon, the... hum, the basic elements of oil.
M: And then they do something to change that gas to oil？
W: Right. First, since coal contains fewer hydrogen atoms than oil, they have to add some extra hydrogen to the gas. Then impurities are washed out with methanol, I think, before this gas is sent on to reactors where it's changed into oil.
M: Since coal is so plentiful I guess it won't be long till this new type of oil will be available all over the place, ah？
W: I doubt it. Prof. Collins said something about the process not be economically enough to use in this country. At any rate, you really ought to talk to him. He'll be able to help you more than I can and he's got office hours all afternoon today.
M: Thanks. He's over in Anderson Hall, right？
W: Right.
How did the woman learn about the process she describes？
强度等级≤C30混凝土气温不高于25℃的运输浇筑及间隙的全部允许时间为 ()。
微信支付 
支付宝支付