Abstract: The valence electron structures of the matrix and the precipitated phases of Mg17Al12 and Mg2Si of Mg-Al-Si alloy were calculated, then the space structures of covalent bonds of precipitated phases were analysed. The results show that the structures of the two main bonds of Mg17Al12 are connected through the weaker bond G and its thermostability are lower. The strongest bond A of Mg2Si has three dimensional structure and does not exist the weaker segment of covalent bond structure, so its thermostability is high. Under room temperature, the strengthening mechanism of Mg17Al12 and Mg2Si lies in their atom bond force far large than that of the matrix and they effective locate the dislocation movement. When temperature is above 120 °C, the bond G breaks and Mg17Al12 disrupts, so it can not play a role of locating the grain boundary and controlling the grain boundary of high temperature. But it is not easy for the covalent bond structure of Mg2Si to disrupt under high temperature, so it can effectively obstruct the movement of the grain boundary and dislocation.
Abstract: In this paper, we focused on a new decorative light density board with a new fiber unit-- micron wood flake, which were large size in length and a very small size in thickness. With these flakes, we processed the light density board in the laboratory, Cunninghamia lanceolata abounded in Fujian Province, Paulownia tomentosa from Anhui Province, L.gemelini Rupr., and Betulaceae abounded in Northeast of China were selected as raw materials, and modified UF as resin. Then several single factor experiments were conducted to discuss the effects of the factors on the physical and mechanical properties of the board, such as board density, resin content, and species of trees as well. The results showed that the density and resin content had significant effects on the mechanical properties of the board. The physical and mechanical properties of the samples, density ranged from 0.3 to 0.5g/cm3, reached Japanese Light Particleboard Standard JISA5908, and the thermal conduction of the board processed with the four species tree were just like solid wood.
Abstract: Soft rot of Chinese cabbage is a common disease that causes serious damage and economic losses. In this study, the control on soft rot of growing and postharvest Chinese cabbage was carried out, using Harpin protein which was the expressed product of a recombinant E. coli strain. The experimental results indicate that Harpin protein preparation containing 3% pure protein powder and 97% wettable powder of Bacillus Thuringiensis (Bt), could effectively control soft rot of Chinese cabbage. The control effect on soft rot reached as high as 90% for growing Chinese cabbage using Harpin protein at 6-10mg/m2 of dosage, and the control effect reached approximately 75% for postharvest Chinese cabbage. Harpin protein stored for 6 months at 20-25 0C had the similarly biological activity with the newly prepared protein.
Abstract: In the present study, a novel phase change material polyethylene glycol (PEG) / titanium dioxide (TiO2) composite was prepared and characterized by DSC, FT-IR, SEM and WAXD. The melting temperature and latent heats of PEG/ TiO2 was determined using differential scanning calorimeter (DSC). The interactions between PEG and TiO2 were analyzed by Fourier transform infrared (FT-IR) spectroscopy. In the form-stable blends, PEG acted like phase change material when the TiO2 served as supporting material. SEM and WAXD tests were performed to investigate the crystalline morphology. PEG/ TiO2 composite were proven a good polymeric phase change heat storage material.
Abstract: A catalyst comprising SO42–/ZrO2 superacid was prepared by impregnation and characterized by FT-IR, XRD, and BET. A novel procedure for oxidative desulfurization of simulated light fuel oil using K2FeO4 over the SO42–/ZrO2 solid superacid was developed. The effects of the oxidantion and extraction conditions on desulfurization were investigated. At temperature of 30 °C, SZ of 0.2 g, K2FeO4 of 0.2 g, reaction time of 1 h, 20 mL of oil is oxidized, followed by methanol extraction at 15 °C for 10 min with the volume ratio of solvent/oil of 1, the results display desulfurization rate for simulated light fuel oil and straight-run gasoline were 88.2% and 89.2%, respectively.
Abstract: An investigation on the melt delivery tube tip pressure and the effective atomizing efficiency of atomizing powder was carried out. The results show that all of melt delivery tube tip pressures are negative value in the atomization gas pressure range of 0.4~0.9 MPa, and they monotonously increase with increasing the atomizing pressure; when the atomizing pressure is higher than 0.7 MPa, the negative pressure of the melt delivery tube tip is slowly increasing with continuously increasing the atomizing pressure; the atomized powder possesses higher effective atomizing efficiency, more uniform size distribution, better sphericity and smoother surface at the atomizing pressure of 0.7 MPa and the pressure of the melt delivery tube tip of -39.44 kPa.
Abstract: Castor-oil stalk is one kind of excellent woody materials, and the thickness swelling ( TS ) of the castor-oil stalk based panel with Urea- formaldehyde resin ( UF ) cannot meet the requirement of the Standard of People’s Republic of China. the TS of the panel was improved with wax emulsion.Results showed that the mechanical properties and the TS of the particle panels were improved as the wax emulsion loading increased. The TS of castor stalk based particle boards and fiber boards can meet the requirement of standard of PRC when 1.44 and 1.2 wt% wax emulsion, respectively, was added.
Abstract: Castor- stalk is one kind of excellent wood materials can be used to make the wood based panel and substitute for the wood resource, reducing the pollution caused by castor stalk-burnt. The properties of the castor stalk based fiber panel are better than the properties of the castor stalk based particle panel made under the same techniques. It studied the infiltrating-characters, the radicals-concentration and the micro-structure of the castor stalk based panel with highly effective surface tension and angle of contact instrument, Electron spin resonating spectrum instrument (ESR) and Scanning electronic microscope (SEM). The results show that the wetting-soakage and the radicals-concentration of the castor fiber are worse than those of the castor particle. The micro-structure of the castor fiber is complete and smooth without crevasse in the castor stalk based fiber panel. But the micro-structure of the castor fiber is not complete and is bruised in the castor stalk based particle panel. So it show that the properties of the castor stalk based particle board are worse than those of the castor stalk based fiber board caused by the micro-structure changed maybe.
Abstract: Castor is one kind of excellent woody materials and can be used to make wood based panel instead of the wood materials. To use the castor stalk better, it studies the chemical composition including cellulose, hemicellulose and lignin by high performance liquid chromatograph (HPLC) and the standard of PRC respectively, the pyrogenation-characters by thermo gravimetric analyzer (TGA) and the relationship between chemical composition and the pyrogenation-characters by SAS. The results showed that the chemical composition and pyrogenation-characters are different in different layers of the castor stalk, besides the castor stalk is mainly pyrolysis in second stage (between 170-330°C).
Abstract: The new type of cushion packaging material that took wood fiber and starch as raw materials was investigated in this paper. Through compression molding, the effects of some parameters on material’s mechanical properties were studied to optimize the technical process, including the ratio of wood fiber to starch, the content of adhesive and foaming agent. Using DPS data processing system for Second-order Polynomial Stepwise Regression to analyze the effects of the different process parameters on the properties and establish mathematical model, so as to optimize the experimental program and ascertain the best conditions, at the same time to verify it. The results show that the ratio of wood fiber to starch is 1:2, 6% AC foaming agent, and 10% polyvinyl alcohol are the optimum parameter.