Advanced Materials Research Vols. 418-420

Abstract: Square-wave double pulse current was used to electrodeposit Ni-W-P-CeO₂-SiO₂ composite coatings in fine-grained structure on the surface of carbon steel, influences of forward pulse average current density, +J_m, in the range of 5~25A/dm² on characteristics of the composite coatings were researched, and the chemical composition_{Subscript text}s, deposition rate, microhardness and microstructures were evaluated by EDX, SEM and Microhardness tester. The results show that the uniform composite coatings can be obtained at +J_m of 20A/dm², which possess higher microhardness of 735Hv. The grains sizes of the composite coatings decrease when +J_m is increased from 5A/dm² to 20A/dm², while the reappearance of large grains structure at 25A/dm².

Abstract: With the increasing rotational speed of the aero-engine shaft and ultra-precision machine tool spindles, there has been the machine tool spindle with ten thousand Rpm. It demands that the spindles should have high rotational accuracy and ultra-smooth surface. In this paper, it takes use of the new ice tool polishing technology to polish metal cylindrical surfaces. The 3D model has been designed. And also the model has been analyzed by Recurdyn software. It verified that the experiment is feasible and effective.

Abstract: Diamond-coated drawing dies are considered as ideal drawing dies for their unique characteristics, such as high hardness, wear resistance and low friction. In order to utilize the superior characteristics of diamond coatings towards improving the drawing performance, the nonlinear FEM simulation is used to simulate the whole stainless steel tube hollow sinking process, with 2D axi-symmetric elastic-plastic element. Based on the simulation results, the distributions of the axial stress and radial stress are analyzed, the influence of parameters of drawing dies on the diameter shrinkage is investigated. Optimal die parameters are obtained.

Abstract: In this work, molecular dynamics simulation was used to investigate the deposition process of a gold nanocluster on rutile TiO₂(110) surface. The effects of surface defects (i.e., point, step, and groove) were examined in terms of interaction energy, morphology and structure. It was found that the gold nanocluster can be strongly attracted to rutile TiO₂(110) surface. Moreover, a higher degree of defect results in a stronger attractive interaction between gold nanocluster and TiO₂(110) surface. The simulated results also indicated that the stability of gold nanoclusters can be effectively controlled by adding citrate ions, which could lead to a high catalytic activity of gold/metal oxide catalysts.

Abstract: Colloidal crystal has attracted much attention both in fundamental crystal growth science and optical applications. This paper reports a simple and efficiency spin-coating method to fabricate high ordered colloidal crystals which have specific structures. We used the cleaned glass slide as substrates, the well dispersity 300nm (±1.2%) polystyrene (PS) spheres aqueous suspension (6.6 wt%) to assemble, and obtained highly organized colloidal crystal thin film by controlling spin-coating condition. Mostly, we got the large area plane hexagonal structure at the first layer and tetragonal construction at the second layer. The mechanism for this stacking way was studied. The obtained thin films were demonstrated by Field emission scanning electron microscope (FESEM) and Fast Fourier transform (FFT).

Abstract: The study on left-handed materials (LHMs) is a international research hot spot in recent 10 years, the LHMs have important application value in many fields, the study of resonance frequency is the focus of LHMs. Periodic split ring resonators (SRRs) structure is one important method of realization LHMs. The further research of the periodic SRRs structure LHMs is very necessary, the practical value and theoretical value. D-SRRs basic structure new LHMs is put forward, the negative refraction effect of the prism experiment is simulated by D-SRRs basic structure new LHMs. By changing the D-SRRs’ geometry size, the influence of the D-SRRs’ geometry size on resonance frequency of the of the new LHMs is discussed. When D-SRRs’ geometry size is smaller, the frequency response shifts from low frequency response to high frequency response, and frequency response is broadened. These results is great significance for realization LHMs near infrared and visible light.

Abstract: The three-dimensional model of purging plug was analyzed by the finite element method. The influence of slit structure (length, width, center radius and numbers) on the maximum principal stress was Contrastive studied in argon blowing process under the same boundary conditions.

Abstract: Field testing of safety characteristic was conducted on fifteen hardwood athletic floor systems with different constructions according to the procedures defined in Chinese standard GB/T 20239-2006 and EN 14904:2006. Device called Mastrad Skid Tester S885 was used to measure the coefficient of sliding friction (COF) of the fifteen floors and devices called Artificial Athlete Berlin was used to test shock absorption (SA) and vertical deformation (VD) of those floors. The COF of the fifteen hardwood athletic floors is between 0.4 and 0.5. About 80 percent of average of VA was between 1.0 mm and 2.0 mm. About 50 percent of the mean of VD was between 35% and 50%. About 50 percent of that was between 50% and 60%. It is vital to add the requirement of uniformity of the safety properties of hardwood athletic floor systems in Chinese standard. The deviation of the friction and VD can effectively be used to discriminate the uniformity of a floor.

Abstract: This paper analyzed the fracture of the tearing NBR 5621 samples under 500mm/min which had been respectively aged for 24 hours at the temperature of -45 °C, 25°C, 70°C and 120°C. It investigated the fracture characteristic of the tearing samples of NBR, which is flat and on it there are some step faceting. The fracture mechanism was also analyzed. The discussion illustrated that the ageing temperature influences the fracture appearance and has little effect on the fracture strength.

Abstract: Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.