Study is made of the impact of La on the corrosion resistance of pure steel through the observation of the morphology of RE inclusion in the pure steel,testing of electro-chemic corrosion EIS and polarization curve.

The distribution and the compositions of large-dimension inclusions in steels was studied through analyses of area distribution of elements with EPMA, and the kinetics and mechanism for formation of RE inclusions were discussed.

This paper studied the possible kinetics and mechanism of formation of large-dimension RE inclusions, discussed the effects of refinement, purification, microalloying and modification of rare-earth elements, taking 5CrNiMo steel with addition of RE and other microalloying elements as example.

The appearance and size of rare-earth inclusions in the AerMet100 steel were observed with SEM,and the micro-mechanical behavior was investigated by the in-situ observations.

According to the situation on back-salinity at clay interlayer in Gansu Shule River irrigation area,the improvement technology on drainage salinity through stand-hole was suggested to adopt in Shule River irrigation area.

This paper deals with the effect on infiltration process of clay interlayer in sand by lab experiments on water infiltration into sand column that contains a clay interlayer.