Advanced Materials Research Vols. 479-481

Abstract: By Fluent 6.3, develop a mathematical model of three-dimensional and three-phase flow in the molten bath of EAF with side accessorial oxygen lance to study the transient phenomena of jet impingement on the molten steel and the molten slag. The simulation result shows, the impingement of the supersonic oxygen jet will cause flow of molten steel and the molten slag by inspiring wave of the molten bath surface from the impinged hollow centre to the bath centre, and will cause vortexes under bath which become the centre of molten steel circumfluence. The velocity of flowing molten steel under the oxygen lance or around furnace wall will be faster than that at the center of bath. With oxygen jet enhance, the frequency of the molten bath surface wave will increase, and the center of vortexes will be more apart from the impingement point of jet and will be lower to the bottom of bath, the number of vortexes will increase and the effect of impingement on molten steel will increase accordingly.

Abstract: According to contact mechanics, the contact regions between the rollers and the steel plate, and then the boundary conditions and FEA model of the roller system of rolling mill are determined reasonably considering the characteristic of the structure and loads. The simulations of the system under different values of loads have been done using FEA and main results are introduced in the paper. The work of this paper offers a reference to calculate the strength or work life of parts in the system and a basis to analyze the roller bearings in the system with 3D FEA in detail.

Abstract: A three Degree-of-Freedom (DoF) mass-spring model is proposed to predict the dynamic response of clamped supported beams subjected to blast loads at the mid-span of the beam. The stiffness of inelastic spring is defined from the relationship between force and mid-span displacement of beams subjected to blast loads. The lumped mass is calculated from the equivalency between the model and beam based on the fundamental frequency. Clamped supported solid beams and T-beams are taken as typical examples to verify the proposed model. And the influence of geometric parameters on deformation behavior is discussed in details.

Abstract: ZnO-Fe₂O₃ catalysts were prepared by thermal decomposition of layered double hydroxides containing zinc and iron within the brucite-like layers and carbonate as the interlayer anion, then the hydrotalcite precursor and mixed oxides were characterized by ICP, XRD and N₂ adsorption/desorption techniques. XRD patterns showed that both ZnO and ZnFe₂O₄ phases appeared for the mixed oxides and their proportion and crystalline degrees depended on the heat treatment temperature. Furthermore, these mixed oxides were tested for the diethyl carbonate (DEC) synthesis from ethyl carbamate and ethanol. More important, the DEC yield could reach to about 32.3% in the bacth reactor under the optimal reactions.

Abstract: Rosewood is a kind of precious wood. Accurate wood species identification is a time consuming task for highly trained human experts. The development of cost effective techniques for automatic wood identification is a desirable goal. Wood color is one of the crucial factors to identify wood species. The color parameters (CIE L*, a* and b*) of eight rosewoods and the relationship between near infrared spectroscopy (NIR) and the color parameters were investigated in this paper. The results showed there was significant correlation between near infrared spectroscopy and color parameters. The correlation coefficients between laboratory-measured and NIR-predicted L*, a* and b* values were 0.93~0.99. The results will be helpful to develop a new method of rosewood identification through near infrared spectroscopy coupled with multivariate data analysis.

Abstract: The fish motion essentially reflects the state of water quality, so it is necessary to study the methods of obtaining the real-time dynamic motion characters of fish body in the field of biological monitoring of water quality. From the point of view of the video, to extract the fish skeleton and to establish the motion model. Based on analysis of the motion model, it is easy to acquire some parameters, i. e. , fish swimming velocity and corner, tail dimensionality and so on. The experimental results show that our model can describe fish swimming, which lie a theory foundation for the fish to participate in the environment pollution research.

Abstract: MgB2 superconducting thin films have been fabricated on Silicon (111) substrate in a two-step ex situ approach. The precursor boron film was deposited by chemical vapor deposition by using diborane as the boron source at 460°C．The Magnesium film with a thickness of about 380nm was deposited on top of the boron film by magnetron sputtering. The samples were then post-annealed in situ in argon atmosphere at 500°C for time range from 2.5h to 5.0h. The sample for optimized annealing time exhibits abrupt superconducting transition, with an onset temperature around 35K and a zero resistance temperature greater than 34K. The microstructures and morphological properties of the films were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Abstract: Multi-component Hf_45.6Cu_27.8Ni_9.3Ti₅Al_12.4 bulk metallic glasses (BMGs) were prepared successfully by casted into the water-cooled Cu mold. Characterization of the casted Hf_45.6Cu_27.8Ni_9.3Ti₅Al_12.4 rods was carried out by X-ray diffraction. The thermal stability and crystallization kinetics were followed by differential scanning calorimetry. The results show that the alloy Hf_45.6Cu_27.8Ni_9.3Ti₅Al_12.4 had a critical cylindrical rod diameter for glass formation, Dc, of 7 mm and the largest cross-sectional diameter (about 12.4mm) can be obtained in the ideal condition. The critical cooling rate for glass formation is 6.48K/s. The Hf_45.6Cu_27.8Ni_9.3Ti₅Al_12.4 BMG has larger glass forming ability and higher thermal stability.

Abstract: when the robot works in an uncertain environment, the interaction force can affect the control system performance and damage control targets, so this paper proposed a Generalized Predictive Control (GPC) algorithm, using multi-sensor fusion with force and position sensors to complete force/position synergic control. The control strategy can guarantee the tracking accuracy of the position and force and make the end-effector move along the constraint surface with a desired contact force. Simulation results of 6-DOF parallel platform reveal the high accuracy of position and force tracking control, meanwhile the robot has strong ability to adapt uncertain environments.

Abstract: Corrosion behavior of (Zr_51.6Cu_48.4)₉₃Al₇ bulk metallic glass in 3 M HCl, 3M H₂SO₄, 3M HNO₃, 3M NaOH and 3.5 mass%(0.6M)NaCl solutions was studied by immersion test and electrochemical measurements. The bulk metallic glass was spontaneously passivated in the acids，alkali and brine, although it exhibits distinct spontaneous passivation with high passive current density in the Cl-containing solutions. The immersion test indicated, except for 3 M HCl solution, low corrosion rates of the order of 10-2 mm/year for (Zr_51.6Cu_48.4)₉₃Al₇ bulk metallic glass in the other solutions, The quantitative X-ray energy disperse spectroscopy(EDS) analysis revealed that the high corrosion resistance of the bulk metallic glass was due to the formation of aluminium and zirconium-enriched passive film. Corrosion products were mainly copper chloride and oxides in the Cl-containing solutions . The growth mechanism of the passive film is also discussed.