Advanced Materials Research Vols. 479-481

Abstract: The design analysis of vertical lathe auxiliary equipment for large pressure vessel processing has been done in this paper. The finite element method has been used to find the main factors which influence the processing precision. The results show that the main factor influencing maximum displacement of overall structure is not the vertical lathe cutting force but the weight of the large pressure vessel. So it is unreasonable to control the processing precision by the whole structure maximum displacement. The horizontal displacement is the main factor in controlling processing precision. The pressure vessel work piece sits on the top plate of the vertical lathe auxiliary equipment. So the displacement of the top plate of the vertical lathe auxiliary equipment is the main factor influencing processing precision. This kind of design thinking has been successfully applied in three type large pressure vessels. It has certain reference value in similar design.

Abstract: The effect of ball milling pretreatment of the starting Ti and B₄C powder blends on the synthesis of dense TiB₂/TiC composite was investigated. X-ray diffraction analysis showed that the TiC phase was not produced until the milling time was up to 18h and only a minimal amount of TiB₂ was generated, even after 48h of milling. It is clear that no complete conversion of the starting reactants to the desired products characterized as TiB2/TiC powder mixture take place within the investigated conditions. The decreased particle sizes of the reactants and high concentration of defects induced from ball milling, allow the completely chemical reaction of reactants into the desired composition (2TiB₂/TiC), corresponding to the rapid and significant sample shrinkage occurring before 500°C. The target products obtained starting from mechanical activation reactants also showed relatively uniform microstructures and densities greater than 98% of the theoretical value.

Abstract: Engineering plastics has many uses, such as national defence, communication and scientific research. In this paper a new experiment plan was proposed in order to get a new engineering plastics forming method. Through the compressive test of polyoxymethylene powder, the process parameters such as temperature, stress and velocity are obtained.Based on the parameters got from compressive test polyoxymethylene powder solid extrusion forming was studied by self-made device. Microscopic analysis and mechanical properties test show that the process parameters are reasonable, the crystallinity increase and molecular chain is oriented along the extrusion direction, as a result the tensile strength and modulus increase greatly.

Abstract: A resonant accelerometer was designed in order to overcome low output precision characteristics of the sensors which were tested with analog signals. This accelerator has the advantages of good repeatability, high resolution and excellent stability. Relationship between linear acceleration and resonant frequency of the sensing unit was deduced and the finite element method was used to simulate the correctness of the design. The theoretical and simulation results are 2984.47 and 2971.27 respectively without acceleration applied on this sensor. When 1g acceleration applied on this sensor, the theoretical and simulation results are 2970.18 and 2951.78 . The relative errors are 0.44% and 0.62% respectively. Finally, the fabricated sensor was tested, and the measured resonant frequency is 3022.55 with a relative error 1.26%, and we give out the possible reasons for this error. The results indicate that this design is feasible.

Abstract: Light gauge steel-light weight aggregate concrete structure is a new type of structure system. This paper introduces the composition, characteristics and production and installation process of this kind of structure. For the Da Yunhe villas, as an example, this paper presents the structure detail and analysis method, and gives the bearing capacity and rigidity calculation result of the typical wall and floor beams, which verify the design code of the steel structure. This paper provides the beneficial reference and basis for future research and promotion.

Abstract: The atomic diffusion and mechanical properties of as-cast AZ80 magnesium alloy after solution treatment at different time were studied by OM,SEM,EDS as well as tensile testing. The results show that the coarse β-Mg₁₇Al₁₂ phase distributed along the grain boundaries as net microstructure is almost dissolved after solution treatment, and the content of Al that in the α-Mg matrix is well distributed with the solution time prolonged. Because of the β-Mg₁₇Al₁₂ phase reducing and granulating, the function of precipitates phase strengthening was depressed and the hardness (HB) of alloy dropped obviously. However, the tensile strength(σb ) and elongation(δ) enhanced remarkably and the yield strength (σ_0.2) decreased slightly.

Abstract: In this paper, Anticorrosive fir was liquefied in phenol, and the liquefied wood was used to produce adhesive by resinification. The effect of resinification time, resinification temperature, mrNaOH/P(molar ratio of NaOH/liquefied wood) and mr_F/P(molar ratio of formaldehyde/liquefied wood) on resinification was investigated by orthogonal experiments in term of the viscosity, solid content and pH of resinification product. Adhesive produced by resinification was then used for plywood production, and plywood strength was detected to assess adhesive. According to experiment results, the optimal conditions of resimification are as follow: resinification time of 140 min, resinification temperature of 90 °C, mr_NaOH/P of 0.5 and mr_F/P of 2.2.

Abstract: This article presents the mechanical properties of PVC coated fabrics under biaxial cyclic tensile loads. Tests of PVC at five load ratios in the warp and weft directions, which are 0:1, 1:2, 1:1, 2:1 and 1:0 respectively, were carried out, and tensile performances of the samples under biaxial tensile loads were analyzed. The test results show that the PVC membrane is highly nonlinear and orthotropic under biaxial tensile loads. With the increase of loading cycles, the total residual strain is nearly unchangeable and the hysteresis curve becomes stable. Slope of warp curve is larger than weft curves, and the weft loop area is greater than the warp one with the same load ratio. The generalized poisson ratio changes due to variations of the load ratio (R). when R<1, the experimental values and theoretical values of the generalized poisson's ratio are negative. When R≥1, generalized poisson's ratios tend to be constant, When the load ratio are 0:1 and 1:0, the curves become straight lines.

Abstract: Air anion and Plant Vitality is the main component of the forest environment; they play a positive role within human and nature. The Plant Vitality and Air Anion Generator which based on Lenard effects can be diffused simultaneously refined gas plants and air negative ions. Furthermore, indoor and outdoor environment can be also improved by Plant Vitality and Air Anion Generator, it has a broad application prospects on hospitals, nursing homes, urban residential areas, parks, schools, and other places.