The influencing factors of coal arch camber in planomural coal bin and coal drop pipe with rectangular or circular cross section during coal drop are studied theoretically.

对落煤过程中平壁煤仓及截面形状分别为矩形、圆形的落煤管起拱的影响因素进行理论研究。

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The precipitous drop in coal prices last year as the world economy swooned has delayed some projects.

而去年全球经济衰退造成的煤价暴跌延误了一些工程。

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Local residents sometimes burn coal to keep warm when temperatures drop.

气温下降时，当地居民有时烧煤取暖。

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On the other hand, if the industry scraps all of its smaller and older plants, Credit Suisse estimates, steam coal demand would drop by 15% to 30%, or as much as 324 million tons a year, while gas demand would increase 8% to 16%, or as much as 3 trillion cubic feet a year.

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The agency also suggested that high coal prices combined with a drop in natural gas prices saw nations replace coal with less polluting gas-powered electricity generation.

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German sources attribute a 400, 000-tonne drop in coal production in May 1943 to the damage caused.

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