摘要:This study focuses on the influence of cement on the water-resistant and physico-mechanical properties of gypsu.m particleboard. The gypsum hydration under the condition of added cement and cold water soluble extractives of poplar was also investigated The results are as follows: 1) the water-resistant property of gypsum particleboard could be improved greatly by adding proper amount of cement; 2)the cement had an hydration of gypsum.
摘要:The stress distribution across the band saw-blade was measured bymethods of stress-strain in this study and the saw-blade vibrations were investigated in the identical accuracy cohditions to determine the relationship between the saw-blade stress distribution and its vibrationResults of the tests have shown that the state diagram of stress distribution across the blade is related to the setting position on thewheels. In the straight span of blade. the proper value of saw-gullet bottom outstriped from wheel rim is about 22mm; in the bending spanof blade, the local high-strain region can be created on the blade neargullet bottom and such high stress Can approach the bending endurance limit of saw steel The stress concentration cracking is easily produced in these regions under the effect of bending pulse circulationof blade. The. average value of vibration amplitude and standard deviation of blade is of significant linear with the tensile stress Theamplitude of vibration is reduced with the increase of the weight strainsystem.
摘要:The purpose of this paper is to investigate the possibility of a computer system which is used to collect and deal with the data of wood cuttingresistance, The results of test show that this computer system can replace the ray-osciilograph system satisfactorily.
摘要:The sugars in five plant materials have been quantitatively analysed with Thin-Layer Chromstography(TLC), Gas Chromstography(GC), and Ion Exchange Chromstography(IEC). The experiments show that each method has its own advantages and disadvantages TLC is easy to operate, but the result is not accuracy enough because of developing samples so often during the test. GC is characterized in not only a better effect on seperating sugars from sample but also a higher measuring sensitivity, its shortcoming is trivial to operate Of the three methods, lEG is regraded as the best one for simply operation. fast determination and accurateresult, but the methodis not practical because of the higher cost of DA—XA anion resin