问题
单项选择题
在建筑设计中常利用封闭空气间层作为围护结构的保温层，封闭空气间层的热阻的大小主要取决于（）。
A．间层中空气导热系数的大小
B．问层中空气的相对湿度
C．间层材料两侧的导热系数
D．问层中空气对流传热的强弱以及间层两侧内表面辐射换热的强弱
答案
参考答案：D
解析：封闭空气间层的传热中，辐射换热占的比例最大，对流和导热占的比例较小。
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在建筑设计中常利用封闭空气间层作为围护结构的保温层，封闭空气间层的热阻的大小主要取决于（）。
A．间层中空气导热系数的大小
B．问层中空气的相对湿度
C．间层材料两侧的导热系数
D．问层中空气对流传热的强弱以及间层两侧内表面辐射换热的强弱
参考答案：D
解析：封闭空气间层的传热中，辐射换热占的比例最大，对流和导热占的比例较小。
One of the most difficult things for children to deal with when moving to a new town is leaving their friends and making new ones. We once moved and one of our new neighbors told us about a summer camp at the Recreation Center all the kids went to. My husband and I looked into it and we found it was unbelievably cheap. I had the kids sign up (报名) the next day so that they could know more kids there. Another thing we did was to have them sign up for sports when school started. They were happy to be on teams with new friends they made. This also gave me a chance to meet new people and from them I sometimes got some useful ideas for my new books. If you’re just moving to a new house in the same city you live in now, it won’t really be a problem unless your kids are changing schools. If they are, it is a great idea to have them take the address book to school. Thus, your children won’t feel “lost” without their old friends. If you’re able to, over the summer vacation, try inviting the friend your child misses most to come and visit your new home for a week, or even a few weeks. I know this can be difficult if that child has to fly, but maybe you can work out a plan with the child’s parents. Think how happy the kids will be when they meet! 小题1:  The author had her kids sign up for the summer camp mainly because _____.
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her kids a chance to meet more kids