1. Cov nyhuv zoo meej, qhov roughness me tshaj plaws, tsawg dua concave-convex.

2.Wtiv taus dej,damp-proof, zoo stiffness, tkub tsis kam, tiv thaiv kev yaig, zoo thaiv-tawm nyhuv.

3.Ccov xim thiab cov xim pleev xim uas siv tau zoo nrog cov xim zoo

1. Kev sau ntawv thiab ntim khoom hauv ntau yam lag luam, xws li khoom noj, tshuaj pleev ib ce, thiab tshuaj
2. Luam tawm cov duab zoo thiab cov ntawv nyeem
3. Cov ntawv lo thiab cov ntawv nplaum uas ntxim nyiam rau cov khoom