根据《城镇燃气设计规范》,进压缩天然气加气站天然气管道上应设(),当气源为城市高、中

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问题:

根据《城镇燃气设计规范》,进压缩天然气加气站天然气管道上应设(),当气源为城市高、中压输配管道时,还应在()后设安全阀。(条款7.2.15)

A.安全阀放散阀

B.截止阀切断阀

C.切断阀切断阀

D.截止阀安全阀

考点:城镇天然气操作工考试城镇燃气设计规范城镇燃气设计规范题库
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饮用水消毒的目的是:()。

A.消灭水中病毒和细菌,保证饮水卫生和生产用水安全

B.去除地下水中所含过量的铁和锰,使水质符合饮用水要求

C.去除水中胶体和细微杂质

D.清除水中的腐质酸和富里酸,以免产生“三致”物质

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光子有能量,也有动量,动量p=h/λ,它也遵守有关动量的规律。如图所示,真空中,有一装置可绕通过横杆中点的竖直轴OO'在水平面内灵活地转动,其中左边是圆形黑纸片(反射光子)。当用平行白光垂直照射这两个圆面时,关于装置开始转动情况(俯视)的下列说法中正确的是(   )
A.顺时针方向转动

B.逆时针方向转动

C.都有可能

D.不会转动

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消化系数

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公路施工企业等生产经营单位发生安全事故,现场人员应立即报告()。

A.有关负责人

B.生产经营单位的主要负责人

C.有关人民政府

D.行业归口管理部门

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"Clean your plate !" and "Be a member of the clean-plate club ! "Just about every kid in the US has heard this from a parent or grandparent. Often, it’s accompanied by an appeal: "Just think about those starving orphans(孤儿) in Africa! "
Sure, we should be grateful for every bite of food. Unfortunately, many people in the US take a few too many bites. Instead of saying "clean the plate", perhaps we should save some food for tomorrow.
According to news reports, US restaurants are partly to blame for the growing bellies (肚子). A waiter puts a plate of food in front of each customer, with two to four times the amount recommended by the government, according to a USA Today story.
Americans traditionally associate quantity with value and most restaurants try to give them that. They serve large portions to stand apart from competitors and to give the customers value. They prefer to have customers complain about too much food rather than too little.
Barbara Rolls, a nutrition professor at Pennsylvania State University, told USA Today that restaurant portion sizes began to grow in the 1970s, the same time that the American waistline began to expand.
Health experts have tried to get many restaurants to serve smaller portions. Now, apparently, some customers are calling for this too. A restaurant industry trade magazine reported last month that 57 percent of more than 4,000 people surveyed believed restaurants serve portions that are too large; 23 percent had no opinion; 20 percent disagreed.
But a closer look at the survey indicates that many Americans who can’t afford fine dining still prefer large portions. Seventy percent of those earning at least $ 150,000 per year prefer smaller portions. But only 45 percent of those earning less than $ 25,000 want smaller.
It’s not that working class Americans don’t want to eat healthy. It’s just that after long hours at low-paying jobs, getting less on their plate hardly seems like a good deal. They live from paycheck to paycheck, happy to save a little money for next year’s Christmas presents.

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