Hybrid poplar boards were subjected to thermo-mechanical densification combined with heat treatment. Hydroscopicity and hygroscopicity of the treated samples were measured. The results showed that dimensional stability of the samples was influenced by compression set significantly. The higher the compression set, the greater the swelling of the samples. On the contrary, the influence of densification temperature and duration was not significant. Thermal modification significantly reduced hydroscopicity and hygroscopicity of the samples. Both higher treatment temperature and longer holding time resulted in better dimensional stability.

Spherical roller bearings are important parts of high-frequency crushers. Using the finite element analysis software to carry on the transient dynamics analysis to the bearing obtains the bearing deformation, the pressure and so on characteristis. Then, by contrasting and analysising, it is found that under pure radial load, radial load and axial load mixed force, influence of cage thickness on bearing performance. The results show that the thickness of the cage has little effect on the deformation of the bearing under pure radial load. Under the combined action of the radial load and the axial load, the radial deformation of the bearing decreases compared with the pure radial load. The deformation of the cage under the mixed load is increased than that under the radial load.

Fast-growing poplars are used as test materials in this study, which are respectively first carbonized then impregnated treatment and carbonized treatment, to test the dimensional stability of modified wood. The results show: the shrinkage rate of specimen which is first carbonized then impregnated is higher than the control group as much as 87.80% ~ 89.16% in radical direction, 76.20%~82.43% in tangential direction; from oven-dry state to air-dry state, the swelling rate of specimen is higher than the control group as much as 5.26% , 9.09%, and to saturated state, the rate is lower than the control group as 14.55% and 0.13% respectively in radical direction and tangential direction, as a result, the characters of shrinkage and swelling are not improved. When carbonized, the shrinkage rate of specimen is lower than the control group as 3.01%~8.47% and 5.08%~5.86% respectively in radical direction and tangential direction; the swelling rate is lower than control group as 23.84%~41.05% and 12.01%~43.75% respectively in radical direction and tangential direction, as a result, the character of shrinkage is poorly improved but swelling is obviously improved. After the two modified treatments, moisture absorption rate is respectively 6.99% and 4.91%, both lower than the control group8.80%; moisture resistance rate respectively 20.57% and 44.20%; water absorption rate 107.27% and 123.74%, lower than the control group 210%; resistance to water absorption up to 48.92% and 41.08%. Know then, carbonization treatment is better in terms of the affect on improving dimensional stability of wood.