Aiming at the problems exiting in grain classification at present, a vertical multistage waterpower device was developed to realize abrasive narrow-grade-classification.
Nanjing sand is anisotropic because of the schistous grain. Its horizontal strength is greater than that in vertical.
片状颗粒成分使得南京砂具有各向异性的性质，其水平向强度小于垂直向强度。
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In the vertical heterogeneous reservoir, the alcohol-induced salt grain could elevate the fluid flow resistance, increase the injection pressure and change the flow direction.