Permeability coefficient is an important indicator of surface wettability and permeability, which influenced by the surface roughness. In this paper, bamboo and fir veneer as raw material, the contact angle of phenolic resin adhesives in different surface roughness of outer cuticle of bamboo, inner skin of bamboo, tight side of Chinese fir veneer and loose side of Chinese fir veneer were measured, and then use the software Spass non-linear fitting for permeability coefficient, and analysis of variance of the results by SAS software. The results show that permeability coefficient of four different kinds of surface variance analysis models are significantly, permeability coefficient of fir veneer is larger than bamboo surface; permeability coefficient of tight side of fir veneer is larger than loose side; permeability coefficient of inner skin of bamboo is larger than outer cuticle of bamboo. Permeability coefficients decrease first and then increased when mesh sandpaper increasing.

Two-step for wood esterification with oxalic acid and cetyl alcohol is developed in this study. The esterified wood powder was investigated by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results show that ester groups substituted parts of the original alcoholic hydroxyl groups, and crystallization occurred during the modification. In addition, surface wettability, moisture adsorption and water absorption tests for wood specimen have showed that the modification improves the moisture and water resistance.

The feasibility of producing biodiesel from Xanthoceras sorbiflia Bunge seed oil was studied. Biodiesel was prepared from refined Xanthoceras sorbiflia Bunge seed oil using methanol and sodium hydroxide in an alkali-catalyzed transesterification process. The refining process consisting of alkali deacidifying was developed to produce biodiesel from crude Xanthoceras sorbiflia Bunge seed oil. The acid value of oil was reduced from the initial 1.28mg- KOH/g-oil to below 1.0 mg-KOH/g-oil in 1 h under the conditions of NaOH 18% , excess alkali quantity 0.2wt% of oil at 30°C. The yield of biodiesel developed by refined Xanthoceras sorbiflia Bunge seed oil was higher than 89% in 60 min using NaOH catalyst that amount approximately1wt.% compared to Xanthoceras sorbiflia Bunge seeds oil as catalyst and a molar ratio of methanol to oil 6:1 at 60°C.

This research aims to provide theoretical proof for the further study on the factors of stress relaxation under different conditions. In this study, use Pinus sylvestris and dynamic stress-strain test system, though change temperature and moisture to research the stress relaxation of wood. The results showed that the temperature and moisture content on the stress relaxation have a significant impact. With temperature enhancing or moisture content rising, stress dramatically relaxation and residual stress rapidly decreased. In other words, the initial stress decreased gradually and the relaxation rate was rise. It was also found that, under same conditions, compared with the tangential section of the Pinus sylvestris, the radial section has larger initial stress and smaller stress relaxation rate. Besides, the initial stress of late wood is larger than early wood but the stress relaxation rate is smaller. Key words: Pinus sylvestris, tensile stress relaxation

With the rapid development of wooden structure buildings in China, the demand for structural plywood enlarges significantly. Eucalyptus and poplar plantation is a very wide area of growth in china, therefore, there is practical significance to use eucalyptus and poplar plantation to produce wooden structural plywood. This study uses orthogonal test on pressing temperature, pressing time, pressing pressure, veneer glue spread - four factors influence the bond strength of structural plywood from Eucalyptus/poplar, and has obtained the superior technology. The results show that hot pressing temperature, pressing time, pressing pressure, veneer glue spread –four factors affect the bond strength of the structure plywood significantly, but the difference among the three veneer glue spread levels is not significantly. The better production technology is hot pressing temperature 135 °C, pressing time 24 min, pressing pressure 1.2 Mpa, veneer glue spread 320 g/m2.