Abstract: Three types of time functions, one-parameter Knothe's model, two-parameter Sroka-Schober's time function and Kowalsk's generalized time function, were introduced and their relationships were analyzed. Based on the Knothe time function, the progressive prediction of surface subsidence due to underground mining was established, and the factor of proportionality describing the influence of geological and mining conditions was determined when there was no measured data in practice. A method of periodic pressure distance to divide the total working face into certain elements considering the mining rate or mining duration was proposed. This approach made the calculation of deformation process in time possible from the set-up entry mining to deadline whether the mining rate changed or not. The experiential formula of the ratio of progressive to final maximum deformation values was obtained with respect to different mining rates and different time factors. The result indicates that this method is effective and easy to apply for analysis in practice compared with 1176 E measured data.
Abstract: For the fluid-solid dynamic coupling question of foundation soil by dynamic consolidation, large deformation hypothesis on the relationship of strain and displacement was adopted to make a non-linear dynamic equilibrium equation and a fluid-solid dynamic coupling equation. In the analysis of a computed example, the distribution regularities of displacement and pore pressure of the foundation in the effective time and space were given. The maximum contact displacement was obtained. The dissipation of pore pressure was worked out. The results coincide the measured data of the highway around Jinan City of China perfectly.
Abstract: The study on the effect of floatation reagent BET on coal and pyrite, which mainly concerned the respects such as surface potential, wettability, ESCA analysis and absorption measurement of coal and pyrite, revealed the mechanism of BET to coal and pyrite. The separation tests of practical samples were carried out. The results manitest that the floatation effect of BET is better than that of other common floatation reagents and has a higher selectivity especially in high-sulfur coal sample floatation.
Abstract: The adsorption capacity for vapor-phase elemental mercury (Hg0) of residual carbon separated from fly ash was investigated in an attempt for the control of elemental mercury emissions from combustion processes. At low mercury concentrations (<250 μg/m3), the adsorption capacity difference of residual carbon to commercial activated carbon is not significantly, but the mercury sorption capacity of commercial activated carbon increase significantly at high mercury concentrations. The mercury sorption capacity of residual carbon was also found to be source dependent. The isotherms of residual carbon were similar to those classified as Type Ⅱ with distinctness different in concave. But commercial activated carbon was more like those classified as Type Ⅲ. Static experiments reveal that prime sites which enhance the mercury adsorption exist in the surface of carbon. Due to the relatively low production costs, these residual carbons would likely be considerably more cost-effective for the removing of mercury from combustion flue gases than other technologies.
Abstract: The mathematical physics essentiality of phenomenological similitude is pointed out to have the same dimensionless models, including the same model structures and the same values of all characteristic numbers in a dimensionless normalized coordinate basis. As an example of metallurgical process, unsteady one-dimension heat transfer conduction is discussed here and one presents that the difference in variant physical phenomena in a dimensionless normalized coordinate basis depends upon the relationships between those parameters, not upon the equations themselves which describe physical phenomena. If there is an unique relationship between physical phenomena in the real world, then their dimensionless relationship in a dimensionless normalized coordinate basis can be found out. The phenomena with the same model structures are called as homogeneous phenomena. If the values of their characteristic numbers are also equal in homogeneous phenomena, then they belong to similar phenomena.
Abstract: The cooling plate was used as the cooling apparatus in 3200 m3 of new No.1 blast furnace and the abnormal operation endangering the cooling plate life was discussed by numerical computations. A three-dimensional unsteady state temperature field mathematical model for the cooling plate and lining was established in the time of abnormal operation. As the slag-metal skull fell off, the gas flow rate and temperature abruptly increased, and peripheral gas overdeveloped, the temperature change of the cooling plate was computed. The influence of the thickness of the slag-metal skull and the cooling water rate on the temperature field of the cooling plate and the heat loss was analyzed.
Abstract: The regenerator in the outlet of a reheating furnace was studied. A one-dimensional unsteady state model was set up, and discretization was gotten through finite difference method. A program of computing the heat saturating time of the solid sphere regenerator was developed by C++ language. The relationship between the heat saturating time and the factors which influence the time was determined. It is shown that the heat saturating time decreases when the heat convection coefficient increases; whereas the increase of heat capacity, density and diameter of regenerator make the heat saturating time increase linearly.
Abstract: The mechanism of dynamics and heat transfer of reducing oxides by carbon in molten slags was analyzed and the relationship between the gas quantity of oxide reduction and time was determined. The foaming equations originated from the reaction were established. A software for calculating foam behavior parameters were introduced. Specially, the determination of the beginning time of rupture foam was discussed in detail. By means of the experimental results of reducing TiO2 in an induction furnace (10 kg) in laboratory, the foam behavior parameters originated from the reaction in the molten slags were carried out through the software.
Abstract: Considering the effect of water slots in the cooling side of copper and the mould taper on the temperature field and stress field of the slab, the coupling thermal and stress FEM model for the continuous mould was presented. The coupling model can reveal the temperature field of the slab and the thermal mechanical deformation of the copper. All the results accord with the fact.
Abstract: The structure and texture of continuous or batch annealing deep drawing and extra-deep drawing steel sheets were observed and analyzed. The results indicate that the surface grain size of the steel sheets is smaller than that of the center by batch annealing, while it is on the contrary of the steel sheets by continuous annealing. The difference is mainly resulted from the original structure and texture inhomogeneity of hot rolled steel plates, and the process of heating and annealing can also have a great effect on the inhomogeneity of the surface and center grain sizes in the steel sheets.
Abstract: The performance of granular γ+(Fe,Mn)3C eutectics reinforced austenite steel matrix composites (EAMC) was studied, and the strengthening/toughness match and wear resistance were analyzed. The results show that hard granular eutectic particles and soft austenite matrix contribute to the strengthening/toughness match of EAMC. The wear resistance of EAMC under low normal load is because of that the eutectic particles under the protection of austenite matrix can delay effectively crack propagation on the subsurface in the process of sliding wear, and the micro-hardness in the strain hardened zone distributes in a negative gradient. The granular eutectic particles are flaked off at high normal load, which intensifies the triple body wear and increase the mass loss of EAMC.
Abstract: The effect of Ga atom on the mean magnetic moment per atom of Fe-Ga alloys was discussed. It is found that Fe-Ga alloys exhibit a markedly different behavior from simple magnetic dilution. With the decrease of mean moment per atom, the moment-per-iron atom increases with the substitution of Ga atom and decreases when the content of Ga atom is larger than 17%.
Abstract: Unilateral compression tests on spray formed 7075+TiC Al alloy at semi-solid state were carried out using a Gleeble-1500 dynamic material testing machine. The microstructures of vertical and cross sections of the specimens after deformation were observed by SEM, and the grain size was measured by a mean linear intercept method. The relationship between the deformation temperature and grain size was analyzed. The results indicated that the grain size increased with the increase of deformation temperature and distributed in 10-21 μm at 580-620℃. When the deformation temperature was up to 610℃ with a deformation rate of 1 s-1, the alloy revealed advantageous thixoforming performance.
Abstract: The polarization curves of titanium alloy TC4 in neutral water and 3%NaCl solution were measured and analyzed. Their cathodic and anodic Tafel slopes were calculated to be much greater than 0.118 V. The cathode process (hydrogen evolution) of titanium alloy in neutrol water was controlled by the reaction H++H++e=H2+ which explained well the cathode Tafel slope was about 0.23 V. The nonstoichiometric oxide TiO1+x(0.5<x<1) as an intermediate product took part in an electrochemical reaction was the controlled step in anodic process.
Abstract: It is found that MgO/Si3N4 composite possesses a self-impedient performance to oxidation. A compact layer on the surface, which is an anti-oxidation and anti-corrosion layer, formed spontaneously in MgO/Si3N4 composite in the process of oxidation, and the thickness and density of the compact layer increase by adding Si or Al into the composite. On the basis of the results, the forming mechanism, the composition and structure of the compact layer of the composites with or without Si or Al were studied. The transform oxygen partial pressure was proposed as a standard for evaluating the escape intensity of gaseous SiO and Al2O. It will show using the thermodynamics and the standard that gaseous SiO and Al2O can produce inside the composite and they reoxidize and react with other oxides in the outside layer to form the compact layer.
Abstract: Lanthanum zirconate (La2Zr2O7, LZ) and La2O3-CeO2-ZrO2(LCZ) powders for thermal barrier coatings were prepared by coprecipitation. The chemical composition of the powders were analyzed by means of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Crystallographic phases were determined by X-ray diffraction technique. Differential Scanning Calorimetry (DSC) was used to analyze the phase stability at high temperatures. The results showed that both LZ and LCZ powders kept the pyrochlore structure and there were no phase transformations for LZ and LCZ at high temperatures.
Abstract: The electrostatic and lubricant performances of compound lubricants -50% EBS wax + 50% graphite and 50% EBS wax + 50% BN in P/M electrostatic die wall lubrication were investigated. The results show that the addition of BN can improve the charging performance of EBS wax, while graphite makes it worse. The combination of 50% EBS wax and 50% graphite exhibits excellent lubricant performance, resulting in a fairly high green density, but the mixture of 50% EBS wax and 50% BN has less beneficial effect. When the mold temperature is 150℃, which is above the melting point of EBS wax, the lubricant performance of the 50% EBS wax + 50% graphite becomes worse, while the 50% EBS wax + 50% BN is little influenced.
Abstract: The viscoplastic model considering dynamic recrystallization describes the coupling process of macroscopic deformation and microstructure evolution during hot working. It is difficult to measure the material parameters accurately by means of traditional testing methods. A hybrid global optimization algorithm is designed, which combines the strengths of genetic algorithm, Levenberg-Marquardt algorithm, augmented Gauss-Newton method and flexible tolerance method. The square sum of the norm of the difference between the experimental values obtained from upsetting experiment and the calculated values obtained from finite element simulation is defined as an objective function. Taking 26Cr2Ni4MoV as an example, the material parameters are identified by the designed algorithm. The comparison between simulated and experimental results shows that the calculated results are well with the experimental. This indicates that the constructed algorithm can effectively identify the material parameters of the model and the model can describe accurately the evolution of microstructure during hot working.
Abstract: In order to set up the synthesis model of a function generating mechanism, the influence of controllable factors and noise factors on the movement precision of the mechanism was analyzed. A mathematical model considering clearance and structural error for the robust mechanism was established and an example of the slider-crank mechanism was given. The results show that the performance of the mechanism is robustness although the clearance and structural error is random variables.
Abstract: Feedforward shape control aiming at the disturbance of rolling force plays an important role in hot strip mills. Based on the principle of feedforward shape control, a GA-based rolling force re-distribution model for industrial rolling mills was proposed. The comparison of test data shows that the model is appropriate and practicable.
Abstract: In order to meet the need of equipment's security and manufacture, the rolling schedule of double stand 4-high reversing cold rolling mills can be made through a promoted integrated iso-load function. The max value of stave radius can be obtained from ANSYS simulation. At the same time the convergency of Stone rolling model is improved. The schedule meets the need of rolling force distribution. It is indicated by experiment that precision of forecasted rolling force is within 8%.
Abstract: Among the tunable filter technologies of optical fiber grating sensors, the peak method is an usual way, but it has poor precision and the result is unstable. A centroid principle method was proposed, which used the detection of wavelength variation by the centroid of scanned light intensity distribution curves. Compared with the peak method, the accuracy is improved 70 times and the error of the wavelength detection decreases greatly.
Abstract: A method to implement the dynamic simulation for an induction motor vector-control system was investigated. The complete simulation model was created with the help of the graphical toolbox of Simulink, being embedded into C++ program, and was transferred to stand-alone software that can generally, dynamically and visually do kinds of simulations for the induction motor control system. The results show that the model derived by the method is accurate and the software is functional well and easy to use.
Abstract: An artificial immune recognition algorithm is proposed. Inspired by the metaphor of the interaction of antibodies with antigens, it processes the data as antigens, and then gets an antibody memory matrix by inspiring or restraining the activity of antibodies. The ability of data recognition and data structure description can be achieved by the memory matrix. The algorithm has the characteristics of recognition variety and self-adjustment. The experiment results demonstrate that the algorithm has good clustering effect and high recognition rate on R2 space data and iris data.
Abstract: Based on the mechanism of B-cell cooperating with T-cell exhibited in biological special immune, an immune controller was proposed. The control features of the immune controller and the PID controller were compared, especially in system output characteristics, anti-disturbance performance and system parameter variance adaptability. The result shows that the immune controller is better than the PID controller.
Abstract: An adaptive synchronization algorithm is proposed and the stability of the algorithm is proved based on Lyapunov stability theory. The chaotic synchronization of Lorenz system and Chen system and that of generalized Lorenz system and generalized Chen system are realized by MATLAB. The simulation results show that not only the same chaotic system with different initial values or different parameters but also two different chaotic systems can be synchronized if the control method is used properly.
Abstract: The key structure of the remote fiber storage network in Tianjin Port of China was developed. The expansibility and data transport protocols were analyzed. The link power budget formula was presented in the long distance optical fiber at the data speed of 10 Gbit per second. It is concluded that the method of merging iSCSI and FC SAN is feasible in designing and implementing remote fiber storage network, which keep the performance steady and decrease the cost. The practical system was implemented successfully.
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
