Advanced Materials Research Vols. 335-336

Abstract: Numerical simulation of deep drawing of bottom of vacuum flask is made by means of finite element software ANSYS/LS-DYNA and the potential defect was analyzed. The influence of the blank holder force on deep drawing quality is discussed .The results show that the maximal value of stress and thickness appears in the round corners of die .The maximal increased thickness is sheet flange and the maximal thinning is the round corners of punch. The larger is the blank holder force, the less equal is the thickness and the poorer deep drawing quality.

Abstract: The tribological property of nano-Cu as additive in lubricating oil was investigated on a stock-on-ring testing machine. Friction coefficient and wear mass loss were discussed in order to study tribological property. And the worn surfaces were characterized by scanning electronic microscopy(SEM). Then wear and lubricating mechanism were discussed. The results show that the wear and friction properties of nano-Cu as lubricating oil additive are excellent. And when the adding quantity is 0.04% and 0.03%(mass fraction), the friction coefficient and wear mass loss is best, respectively.

Abstract: In order to take exploratory well, production well ( development well), and reservoir p-retection into account. Multi-functional treatment agent used in drilling fluid and completion flui-d which called MFA-1 has been successfully developed by the equilibrium principle of dispersion and accumulation. The result shows that MFA-1 is fluorescenceless and low (no)toxicity. Also, it has many perfect properties such as filtration reducing, lubrication, anti-collapsing, plugging, re-servoir protection, strong anti-temperature (＞150°C) ,strong anti-salt,ect. Its whole effect is bett-er than sulphonating asphalts HL-Ⅱ and SAS.So MFA-1 is a good succedaneum of sulphonating asphalts.In more than 20 wells of Tarim Oilfield,drilling fluid and completion fluid which prepared with MFA-1 has been successfully used to solve many problems. Such as drill pipe sticking w-hile testing and the underground complex incidents,ect. As a result,it takes good social benefits a-nd good economic benefits.

Abstract: Molecular dynamics (MD) simulations have been carried out to investigate the defect’s effect on the mechanical properties of single-crystal copper nanowire with different surface defects, under torsion deformation. The torsional rigidity is found insensitive to the surface defects and the critical angle appears an obvious decrease due to the surface defects, the largest decrease is found for the nanowire with surface horizon defect. The deformation mechanism appears different degrees of influence due to surface defects. The surface defects play a role of dislocation sources. Comparing with single intrinsic stacking faults formation for the perfect nanowire, much affluent deformation processes have been activated because of surface defects, for instance, we find the twins formation for the nanowire with a surface 45^o defect.

Abstract: To obtain a view of the shear deformation mechanism, ideal shear strength and hardness in superhard nanocomposites nc-TiN/a-BN films, we studied, using the first-principles calculation method, the shear stress-strain response of a theoretical interfacial system TiN/BN/TiN, which consists of two TiN slabs and one sandwiched BN monolayer. The shear process showed that decohesion happens at the Ti-N interplanar bonds next to the interface. The calculated results show that the TiN/BN/TiN interface has the hardness that can match the TiN/SiN/TiN syatem.

Abstract: The anti-corrosion performance of Tiangang TP95S casing steel was studied by high temperature autoclaves simulating the high-temperature and high-pressure H₂S/CO₂ environment. The experimental results show that the corrosion rates increase with the rising of temperature which is from 40°C to 80°C under the dynamic and static conditions of the simulated environments; the dynamic corrosion rates are between 1.7294 and 1.8601mm/a and the corrosion rates are 0.4264～1.2715mm/a under the static conditions, both of which belong to a serious corrosion category; the dynamic corrosion samples have had the localized corrosion at 40°C, but the local corrosion of the static corrosion specimens appeared at 80°C; the corrosion product of TP95S steel takes FeS as the core in the case of static corrosion at 40°C.

Abstract: The precision forging processes for gears have advantages in saving material and energy consumption, reducing the cost and improving the quality of products. Gears have complicated geometries and are difficult in precision deformation. Two kinds of forging process of gears were put forward according to the structure characteristic of gears. 3D FEM model of the precision forging process of gears was established. The forming laws, material plastic behavior, changed geometries and the qualities of the workpieces are explored by finite element simulation. According to the simulation results, completely filled gear teeth were obtained using a lower forging load by the designed process which is the effective forging process for manufacturing of gears. From this study, it was expected that designed process could be efficiently used in the gear forging for practical use in the industry.

Abstract: Abstract: Objective: To study the antibacterial efficacy and the catalytic capability of nanocrystalline magnesia powder(nano-MgO). Methods: The antibacterial efficacy was evaluated in Bacteriostatic circle and the shake flask test and the catalytic capability was evaluated by paraoxon. Results: The nano-MgO had good antibacterial efficacy and highly catalytic capability. The catalytic capability was not influenced by light. When 50mL 20μg/L paraoxon solution was catalyzed by 0.5g nano-MgO for 5min, the disappearance of paraoxon was about 77.9%, and for 60min, the disappearances of them was 99.6％. Conclusion：The nano-MgO had good antibacterial efficacy and highly catalytic capability. Key words: nanocrystalline magnesia , antibacterial efficacy, paraoxon, catalytic degradation

Abstract: Due to its suitable band gap, low cost, environmental friendliness, and high electron mobility, ZnO, naturally n-type semiconductor with a wide bandgap (Eg = 3.37 eV), is widely studied, as a window layer of heterojunction solar cells. In this study, the ZnO nanowire arrays were grown on the different ZnO seed layers by hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-Vis spectra were used to characterize the ZnO nanowire arrays. The results indicate the seed layer can effect the size distribution, density, crystal structure and optical properties of the nanowire arrays.

Abstract: The NC incremental sheet metal forming technology is a flexible forming technology without dedicated forming dies. The forming locus of the forming tool can be adjusted by correcting the numerical model of the product. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation, the deformed region of sheet metal thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The principle of NC incremental sheet metal forming and the forming process of the fender are introduced. The effect of process parameters on forming is analysed. The improvement method of the forming quality is suggested. The groove is created in the starting point of tool moving when the starting point of tool moving locus at all layers is identical. The groove can be eliminated when the starting point of tool moving locus at all layers is different. The feed pitch p increase, the process time decrease, production rate and surface degree of roughness increase. In general, the feed pitch is 0.25mm.