The optical flash accompanying GRB 990123 is believed to be powered by the reverse shock of a thin shell. With the best-fit physical parameters forGRB 990123 an
In order to elucidate the regional export variation of particulate organic carbon in the western Arctic Ocean, samples vertically integrated between 0 and 100 m
According to the characteristics of water and erosion environments of different natural zones on the Loess Plateau, this paper studies changes of vegetation typ