Abstract: According to poor integrality of overlaying rock in Beiminghe Iron Mine, China, a research was done for predicting the subsidence of metal mines based on geographic information system (GIS) and probability-integral method. A three-dimensional (3D) calculating model related to geographic, geologic and inherent information was built. By using the effective spatial analytical function and the drawing tool of GIS, the analysis results intuitively show the degree and scope of mining subsidence.
Abstract: In order to study the reasons and preventive measures of dynamic disasters such as shock bump and the destroy of rock mass in mining engineering resulted from the outburst of mash gas and coal during mining, stress-relieving measurement and temperature and confining pressure calibration were made with improved CSIRO cells at 4 measurement points in Datong mining area. Based on the measured results the in-situ stress tensor of each point was computed by a special computer optimization program, and the relationship between in-situ stress and geological structure was analyzed with the geological structure factors of the mining area. The rules of in-situ stress distribution and the relationships between in-situ stress and geologic structure in Datong mining area were obtained.
Abstract: The method, experimental equipment and results of column leaching were presented for low-grade copper sulfide ore. The experiment was carried out in 8 organic glass columns. The effect of process parameters, such as bacteria variety, ore particle size, aerating and leaching period on the bioleaching rate was investigated. During the period of 167 d, the copper leaching rate was 80.75% by Z08090-O strain with-12 mm ore size. Using common domesticated species Acidithiobacillus ferrooxidans, the copper leaching rate decreased because of acid accumulation in the ore containing large quantities of pyrite but little acid-consuming gangue. However, by Z08090-O strain, the copper leaching rate was higher.
Abstract: The effect of alloying element vanadium on the thermodynamic equilibrium phases and the transformation temperatures A3 and A4 of T122 ferritic heat resistant steel were studied by Thermo-Calc software. The results show that the main precipitated phases in T122 steel are M23C6, MX and Laves phases. When the mass fraction of vanadium is less than 0.15%, a little Z-phase precipitates, and the content of Z-phase linearly decreases with increasing vanadium content. When the mass fraction of vanadium is more than 0.28%, two different types of MX precipitate. With increasing vanadium content, the proportion of MN phase decreases, but the proportion of M(C, N) increases. The effect of vanadium content on M23C6 and Laves phases is extremely limited. As a closed austenite region element, the transformation region between ferrite and austenite becomes small with the increase in vanadium content.
Abstract: Duplex stainless steel (DSS) SAF2205 and micro-alloyed steel X65 were welded by metal inertia gas welding (MIG) with ER2209 welding wires, and the welded joints have good mechanical properties. The type II boundary close to the fusion line at the micro-alloyed steel side was observed by SEM. Obvious concentration gradients of Ni and Cr exist in the region between the two boundaries, where the hardness is much higher. The mechanical properties of the welded joints were investigated by using smooth and notched tensile test and low temperature impact test, and the polarization curves of different weld regions were also tested in 1 mol·L-1 NaCl solution. The notched tensile strength and impact toughness of the welded metal are lower than those of DSS base metal, but the corrosion potential is higher. The mechanical properties of X65 heat-affected zone (HAZ) is as good as the base metal and the corrosion potential is higher.
Abstract: It was analyzed that rolling oil stains form on the surface of an aluminum foil when the aluminum foil was annealed after roUing. The curves of thermal gravity and differential thermal analysis of rolling oil and additive were determined by means of a differential thermal analyzer. The results indicate that rolling oil has two phase changes with the increase of temperature. At first, rolling oil is volatilized in a large scale, and then oxidation occurs. The oxidation process is the main reason for the stains forming on aluminum surface, which theoretically reveal the effect of the thermal properties of rolling oil on the annealing surface.
Abstract: Mg60Cu30-xY10Six(x=0,1.0,1.8,2.5,5.0) bulk amorphous alloys were prepared by copper mould casting. The experimental results show that the alloy with x=1.0 has the largest glass-forming ability among Mg60Cu30-xY10Six(x=0, 1.0, 1.8, 2.5, 5.0) alloys. The microhardness and fracture toughness of Mg60Cu29Y10Si1 alloy are also significantly improved compared with those of Mg60Cu30Y10 alloy, but its supercooled liquid region (ΔTx) decreases slightly. However, the reduced glass transition temperature (Trg) of Mg60Cu29Y10Si1 alloy is larger than that of Mg60Cu29Y10Si1 alloy.
Abstract: Titanium dioxide nanotube array films on Al plates were prepared by liquid phase deposition (LPD) method. The sampies were annealed at various temperatures. The phase and microstructure of the nanotube array films were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It is found that the phase of as-deposited TiO2 array film without heat treatment is amorphous, but there is anatase in the film after heattreating at 400℃ for 2 h. The structure of TiO2 array film after annealed at 650℃ for 2 h in air is still stable, The presence of alumina promotes the thermal stability of TiO2 nanotube array films and suppresses the growth of crystal grains and primary particles.
Abstract: The calcination process of metallurgical active lime in a rotation kiln was simulated in laboratory. It is found that preheating temperature, pre-heating time, calcination temperature and calcination time are the most important factors in this process. The optimal parameters is the pre-heating temperature of 700℃, the pre-heating time of 60 min, the calcination temperature of 1150℃, and the calcination time of 15 min. Under this optimal condition, the activity of active lime produced by the raw material of limestone from Xuanhua Steel in China is 410 mL.
Abstract: To evaluate the aging behavior of acrylic polyurethane coating/carbon steel system, an artificial accelerated aging test was carded out with the aid of a xenon lamp. The aged coatings were characterized with Fourier transform infrared spectroscopy (FTIR), optical microscope and vancometer. The corrosion resistance of the aged coatings was evaluated by salt spray test, and the effect of photo-radiation on the corrosion of the metal underneath the coating was investigated preliminary. The results show that the coatings with different aging periods all keep good protection state after salt spray test. However, the metal underneath the coating is corroded more severely with the increase of aging time. It can be concluded that the C-N bond of the coating breaks after the exposure to photo-radiation, which causes the increase in surface roughness and the decrease in gloss with the increase of aging time. Furthermore, these surface changes build the access to the underneath metal, which accelerates the penetration of medium into the coating and therefore makes the metal corrode severely.
Abstract: Artificial accelerated weathering test on thermoplastic elastomer SBS was conducted by using a fluorescent UV/condensation weathering device. The changes in surface color, morphology, structure and mechanical properties were monitored by spectrometer, microscope, Fourier transform infrared spectroscopy and tensile testing machine. The results showed that the surface color of SBS turned to yellow with increasing aging time, and the cracks became dense gradually. Carbonyl (>C=O) group was observed from ATR FTIR spectrum. The elongation at break, tensile stress at break and tear strength decreased quickly in the initial stage of aging procedure and then stabilized, while the Shore A hardness increased with the increase of aging time. The mechanical properties turned to be hard and brickle with the evolvement of aging. The change of elongation at break can be used to detect the degradation of SBS.
Abstract: The equation of groove surface for skew rolling copper balls was defined, and the characteristic curves were obtained by VC++ programming. A three-dimensional entity model of the roll was established by Pro/E software. The three-dimensional nonlinear finite element method was used to numerically simulate the metal forming process of copper balls by DEFORM-3D analysis software, and the stress and strain distributions were presented from this simulation.
Abstract: The dynamic explicit finite dement software LS-DYNA was used to numerically simulate H-beam rolling by a universal mill. The metal flow pattern in a workpiece was studied with the simulation results of node displacement in the rolling plane. It is shown that there are zero displacement lines in the workpiece in the horizontal and vertical rollers' depress direction, which indicate that there is a neutral flow plane of displacement, in company with metal inversion phenomenon at the flange's end.
Abstract: In order to simplify the three-dimensional geometrical model of rail rolling by a universal mill, the vertical roll with box pass was simplified as an equivalent flat roll firstly. Then the kinematically admissible velocity fields of the web, head and base of a rail were determined. Based on these velocity fields, the plastic deformation power, the powers consumed on the velocity discontinuity surface and the powers generated for backward slip and forward slip were calculated. According to the variation principle, the roll forces of a horizontal roll and two vertical rolls were obtained. Compared with experimental data, the values of roll force from the upper-bound method are somewhat greater than experimental data but do not exceed them by 20% in general. The method with the variation principle is reliable and feasible to preset and optimize the parameters of rolling technology.
Abstract: The closepacked edge wave appears in the process of payingoff (color coating line) after coiling process in continuous galvanizing line, and the uncoated area on the edge makes the strip out of use. By measuring the spot and analytically calculating the plastoclastic deformation of the strip in coiling process using the iteration of layer by layer, the effects of the number of coiling layers, coiling tension, strip thickness and minus crown on the stress field and displacement field of the strip in coiling process were quantitative studied, and the mechanism of generating this phenomenon was revealed. Based on the analytical results and measured data, the coiling technological parameters was modified, the defect of edge buckling generated in coiling process was effectively controlled, and the up-to-standard rate of products was markedly upgraded.
Abstract: Based on the measured data of mould temperature during continuous casting of round billets, the feasibility of using neural networks to solve the inverse problem of heat transfer of a continuous casting mould was discussed. The combination of neural networks with numerical simulation was proposed to calculate the heat transfer of the mould. The results show that the temperature and heat flux field calculated are in agreement with the experimental ones, which could correctly reveal the characteristics of non-uniform heat transfer around the mould circumference.
Abstract: The compliance matrix describing the rotation capacity of flexure hinges was analyzed. A multi-objective optimization model was established to enhance the rotation capacity of flexure hinges with the important factors influencing the rotation capacity of flexure hinges as design variables. The optimal design model by using Powell inner point penalty function method was presented, and the design example of a circular flexure hinge was optimized based on the model. The optimal result indicates that the method is valid and practicable. The comparison of rotation capacity between before and after optimization shows that the performance of the flexure hinge after optimization is better.
Abstract: In 2D and 3D, the magnetic flux density from a micro electromagnet used for magnetic bio-separation was simulated with FEMLAB software. Due to the complexity of the structure, a fine meshing of the 3D structure is not possible. In order to minimize the memory consumption by reducing the size of the space domain surrounding the magnetic structure and by using a relatively coarse mesh, the effects of reducing the size of the space domain and using a coarse mesh that it is possible to perform a reference simulation with a large space domain and a fine mesh, and the errors made by the approximations were quantified. 3D simulations were carried out with space domain and coarse meshing conditions identical to those in 2D simulations, and it is shown that the approximations in 3D simulations result in an underestimation of the order of 10%. The magnetic structure of 3D simulations can be compared with that of 2D simulations.
Abstract: A complex coupling model for wide strip tandem cold mills was established based on systematic analysis on the factors affecting on shape, gauge and tension. Aiming at the characteristics of the model, ordinal decoupling design was put forward which could simplify decoupling process more explicitly than normal decoupling design, and the simplified method of decoupling channels was given for practical application. Based on actual rolling parameters of the first stand of a 1250 mm 8-high 5-stand tandem cold mill, the ordinal decoupling system after simplified was analyzed by Matlab/Simulink tools, and the results show its decoupling effectiveness.
Abstract: On the basis of electrode control in Anyang Steel, a prediction model was established by adopting data mining technique and applied to parameter tuning of an electrode control system. First the data mining process of the electrode prediction model was introduced. A variable structure generic Elman neural network, which can evolve the network structure, the weights and self-feedback gain coefficient simultaneously, was proposed based on a new hybrid generic algorithm and data mining algorithm. The Elman based on BP algorithm and the variable structure generic Elman neural network were applied to establishing of an electrode prediction model for Anyang Steel. The simulation results based on the spot real data of Anyang Steel show that data mining algorithm combined with the variable structure generic Elman neural network has better dynamic characteristic, faster approach speed, better precision than BP algorithm. Finally, when this model was applied to parameter tuning of the electrode control system in Anyang Steel, its control effeet was remarkable.
Abstract: A nonlinear prediction method based on phase reconstruction of multivariate time series was proposed. Together with the candidate time series for prediction, the correlated information of the same nonlinear dynamical system was selected to construct a multivariate time series. In the phase reconstruction space of the multivariate time series, a local multi-variant linear regression model was used to forecast the evolution data of phase point, through which the future data of the candidate time series were predicted. Since the coupled relationship among different variants of the dynamical system were taken into consideration, the reconstructed phase space had more dynamical information and phase point trajectory more approximated the original dynamical behavior. Compared with the univariate method, for either one-step or multi-step prediction, the new method has better prediction preciseness with less sensitivity to the selection of embedding dimension. The validity of the new prediction method was verified by the results of prediction experiments on the Lorenz system.
Abstract: A detection algorithm of moving objects based on background subtraction method was proposed for a video surveillance system with static camera. Some multi-background models dealing with RGB colors were built during the leaning process without any restraint. The modes can be updated in good time with the change of background during moving object segmentation. Chromatic difference and cross-entropy were employed to eliminate shadows and made the moving object areas more accurate. This algorithm demonstrates better performance in the experiments with video sequences captured by a general USB camera.
Abstract: Under the background of the nonstructural data mining model, a Web text clustering mining algorithm based on the discovery feature sub-space model (DFSSM), W, TCDFSSM algorithm, was proposed, which can distinguish the most meaningful features from the concept space without any evaluation function. The WTCDFSSM algorithm was applied in the modern long-distance education net. The result shows that it can automatically congregate the text information of education field, which is collected from education sites on Internet, help people to browse the important information quickly by information navigation mechanism and acquire useful knowledge.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
