研究了两种烟煤和玉米淀粉、石权子粉粉尘层的反应动力学参数。
A study on reaction kinetics of maize , lycopodium and two kinds of bituminous dust layers are presented .
不管是石油、玉米、铁矿石、煤炭、棉花还是铜，价格都在快速下跌。
Whether it is oil , corn , iron ore , coal , cotton or copper , prices are falling quickly .
玉米石