The paper pointed out that coal, as a major primary energy, its import and export have bearings on energy safety, environmental pollution and social stability.
指出煤炭作为我国主要的一次能源，其进出口问题关系到我国能源安全、环境污染和社会稳定。
2
The roof of cavern is regarded as an elastic beam with support at the midpoint and the coal pillars are regarded as bearings so as to establishing a cavern roof-coal pillar system.
将顶板视为中点有支承的弹性固结梁，将煤柱视为支座，形成了顶板-煤柱系统。
3
Housed bearings are employed widely in coal fired stations, for example on coal feed conveyors.