Abstract: The vertical boreholes were drilled from the surface for correlation detection of the damage height of overburden rock mass. The expanding height of the inner collapsed zone and the permeable fractured zone as well as their distribution in the overburden rock mass after excavation of the coal seam were determined based on the leakage volume of drilling fluid, the change of water level in the boreholes and the borehole images by color TV.
Abstract: Rollback smoke is one kind of familiar turbulent flow during mine fire and may cause serious damage and injury. The rollback law of reversal smoke flow is significant to mine fire rescue. The theories of environmental fluid mechanics and heat transfer are applied to study on the rollback law of the reversal smoke flow in a horizontal airway during mine fire. The heat transfer process between the reversal smoke and the airway wall is analyzed. Through the analysis above, the rollback distance equation of the reversal smoke is formed. The mass flux of the reversal smoke flow at the reverse point above the fire source and under the roof and the temperature at the point before smoke reverse again are the key points of working out the equation. At the stagnation before smoke reverse again, namely at the stagnant point of the reversal smoke, the pressure between smoke flow and airflow is equal and thus a pressure equilibrium equation is built up. Combined with the smoke plume model and gas state equation, the mass flux of the reversal smoke and the temperature at the stagnant point are worked out. At a result, the function of rollback distance of the reversal smoke is educed and simplified in order to be used in practice.
Abstract: The experiment was carried out to investigate the possibility of removing soluble lead from lead-containing waste water by using granular sludge as a media. The results show that granular sludge has a good ability to remove lead from lead-containing waste water. The removing rate can be above 95%. Sludge content, pH value and sedimental time are major factors which affect the treating results of lead-containing water. With a initial lead content of 20 mg/L, the quality of the treated water can reach Chinese national standard of discharging.
Abstract: Denitrification during hot metal pretreatment is studied under laboratory conditions in the range of 1573-1673 K. The results show that the oxygen, sulphur and carbon contents can somewhat reduce the nitrogen solubility in molten iron, and the nitrogen solubility is in linear regression relation with the carbon content. The effects of the initial carbon content on denitrification is obvious. At the same intensity for offering oxygen, the amount of removing nitrogen increases with increasing the carbon content in the hot metal. It is also found that effective denitrification takes place during decarbonizing in the pretreatment. The denitrification ratio is improved with the amount of decarbonization increasing. The lowest nitrogen content at the end point reaches to 13×10-6, and the denitrification ratio exceeds about 50%, which can meet the demand of ultra-low nitrogen steels for nitrogen content in molten iron.
Abstract: A mathematical model was proposed to calculate the stress distribution of the solidification shell in a slab mold based on the local heat flux calculated by using the measured temperature of the copper plate. Solidification equations to liquid steel were built and discreted by the finite element method. ANSYS commercial software was used to solve these discrete equations, the stress and strain distributions were obtained and the taper of the mold was decided according to these calculating results.
Abstract: A simulation method of dense particle-gas two-phase reacting flow in the mixed Eulerian-Lagrangian approach is proposed, and the comprehensive model covers the two-phase turbulent flow, heat transfer and chemical reactions. The model is used to numerically study two-phase reacting process in a circulating fluidized bed. Detailed results on cluster structure, cluster size, particle volume fraction, gas velocity and particle velocity are obtained. The simulation results are reasonable, and are in agreement with experimental ones. It is concluded that the model and algorithm are feasible and can be used to study the dense particle-gas two-phase flow efficiently.
Abstract: The cold deformation behavior of 302HQA stainless steel was systematically investigated through compress tests at room temperature. By means of microstructure and X-ray diffraction analysis, deformation-induced martensite transformation (DIMT) was found in this alloy during the cold forming process. The result of magnetic measurement shows that the amount of deformation-induced martensite increases with the increasing of plastic strain. When the plastic strain is lower than 30%, the amount of martensite increases with the increasing of strain rate, while the plastic strain is up to 50%, the amount of deformation-induced martensite decreases with the increasing of strain rate due to the effect of deformation-induced heat accumulation.
Abstract: The effect of pressure, gas atmosphere and W particle size on the shrinkage kinetic curve of nano-scaled W-Cu composite powders during hot pressing were studied. The growing of W grains in W-Cu alloys was analyzed. Some mechanical properties were measured. The results show that, using composite nano-powders of W-Cu, the nano-scaled W-Cu alloy in which W particle size is not more than 0.5μm can be obtained through hot pressing in H2 atmosphere and under a high pressure of 75 MPa at low sintering temperatures of 970-1200℃. The relative density of the ultrafine grained alloy can reach 98.8%. The mechanical properties at 500℃ greatly exceed those of the conventional W-Cu alloy.
Abstract: SEM, EDS and electrochemical measurements were used to investigate the structure and electrochemical characteristic of the hot-dipped Zn-0.2Al-Mg-Re alloy coating. The results indicated that the coating was composed of three layers: surface β-Zn sosoloid layer, middle 5 phase (FeZn7) layer and inner Γ phase (Fe5Zn21) layer. There were three steps both in the constant current electrolysis corrosion curve and the corrosion potential curve of the coating in 5%NaCl solution, which showed that different phase layers of the coating had discrepant electrochemical characteristic. The corrosion potential of the coating in 5%NaCl solution increased from the surface to the inner phase layer. There was no obvious passive characteristic in the anodic polarization curve and the corrosion process was controlled by the reduction reaction of oxygen, which would probably be caused by the structure and corrosion products of the coating.
Abstract: The binary systems of polyalcohols have potential use for heat storage. The experimental phase diagram of the binary system pentaerythritol-tris (hydroxymethyl) aminomethane (PE-TAM) was established from room temperature to the liquidation temperature by two techniques: differential thermal analysis (DTA) method and IR spectra at various temperatures. The result shows that the phase diagram includes of two eutectoid invariants and one peritectic invariant. The behavior that polyalcohols are orderded at low temperatures and disordered at high temperatures is the important factor affecting the miscibity in different phases of the binary system.
Abstract: An oscillator-type tribometer was used to determine the friction factor of lubricated sliding pairs made of poly (vinyl alcohol) hydrogel/poly (vinyl alcohol) hydrogel and human articular cartilage/poly (vinyl alcohol) hydrogel respectively, and the research of the lubricating mechanism was carried out according to Stribeck curves. The experimental results show that when the hyaluronic acid (HA) is used as an artificial synovial fluid, poly (vinyl alcohol) has similar frictional characteristics with human articular cartilage and the friction factor of poly (vinyl alcohol) hydrogel/poly (vinyl alcohol) hydrogel is smaller than that of human articular cartilage/poly (vinyl alcohol) hydrogel. It is concluded that the two lubricating mechanisms are both liquid film lubricate.
Abstract: The change of deviation angle of universal joints and the angular velocity fluctuation of the driveline in a vehicle using A frame during vibration was analyzed. The installed angle of the rear bridge determines whether the driveline is Z or W arrangement which affects the angular velocity fluctuation in driveline differently during vehicle vibration. When the swing angle of the driveshaft is smaller than that of A frame, Style W is better than Style Z. Equations were given to solve the installed angle of the rear bridge in Z and W arrangements. An approximate way was proposed to decide which arrangement is better for a certain vehicle with A frame.
Abstract: A physical and mathematical model for slabs heated in a 3-zone walking beam type of re-heating furnace was established. The finite difference method was used for discretization of the physical and mathematical model and a computational software was developed according to the software engineering theory. The results indicate that raising the temperature of reheating zone, the slab initial temperature and the emissivity of furnace gas can improve slab heating efficiency while guaranteeing the final quality of slabs. Reduction in heating zone temperature can decrease energy consumption and prolong the furnace campaign life.
Abstract: The fundamental principle of flow-jet boiling enhancing is proposed. The water column caused by normal pressure water thrusts through the water layer at a certain velocity to directly contact the plate surface. A nuclear boiling area can be established and intensive boiling will occur. The effect of the extreme cooling area on the entire cross section of the steel plate can be obtained via an optimized experimental research on the outlet velocity, height, diameter of flow jet and distance between adjacent water columns. For a plate of 20 mm thick, the cooling speed is up to 45.2℃/s and the shape precision up to 3 mm/m.
Abstract: According to the fact of hot strip mills, a dynamic simulation model was put forward, and the dynamic simulation for the AGC of hot strip mills was implemented. The effects of some factor on the products was researched. The results show that the model is simple and appropriate and is suitable for analysis of multiple factors.
Abstract: A method was proposed for achieving the automatic adjustment of parameters in both the decoupling network and the regulator according to the adaptive rule. Simulations show that the method avoids the effect of variable parameters and ensures the quality of the decoupling.
Abstract: The control system based on a linear model has large error and tension fluctuating when the flying gauge changes in tandem cold rolling mills. In order to solve the problem, a PID decoupling control method based on the recursion subsection linear model was presented. Simulations were carried out for a 5-stand tandem cold rolling mill using the method. It is found that the accuracy of AGC system is satisfied and the need of flying guage control can be met.
Abstract: The accurate diagnosis of rolling bearing was studied. The wavelet packet analysis was used to abstract the characteristic of signals. The signals were decomposed into eight frequency bands and the information in the high band was used as a characteristic vector. RBF neural networks were used to realize the map between the feature and diagnosis. The analysis of data sampled form a workshop testified correctness of the method proposed.
Abstract: An adaptive fuzzy control algorithm for antilock brake systems was presented. An adaptive fuzzy controller and a slip regulator were designed according to the longitudinal vehicle brake model. The optimal slip ratio was identified from the input and output parameters of vehicles, and the control parameter of the systems was adjusted by the slip regulator to improve the performance of the control systems. The algorithm was verified by simulation experiments.
Abstract: Based on analyzing some drawbacks of existing online monitoring systems and the evolution trend of remote diagnosis systems, an architecture of the distributed remote diagnosis system was presented using CORBA specification. Some key technologies for implementing the remote diagnosis system were discussed such as POA strategies, Naming Service, Event Service, CORBA Component Model as well as Database Integrate. The fundamental function modules and implementation details of the diagnosis system for enterprise level and remote diagnosis centers were focus on. The most functions discussed have successfully used in industry.
Abstract: With the multi-dimension mass flow controlling theory of metallurgy manufacture procedure, this paper has analyzed the parameters for ironmaking/steelmaking interface, such as plant spatial configuration, time factor, conveyance quantity and temperature of hot metal, and introduced the concept of quantity to mass flow controlling procedure. These analysis data are the basis of the integrated optimum of blast furnace-pretreatment-converter manufacturing procedure. The conclusion is that the joining and matching procedure is key to produce stability, and the joining shortcoming of manufacture procedure at BaoSteel is pointed out.
Abstract: An incremental algorithm for inducing decision trees is presented based on ID3 algorithm. The complexity of the incremental algorithm is analyzed in terms of instance-count additions and e-score calculations. The same training instance shows that the incremental algorithm can induce decision trees equivalent to those forms by ID3 algorithm.
Abstract: To increase product quality and predict the unqualified products, effective control methods must be selected. Considering the disadvantages of process capability indices Cp and Cpk that are hard to help to find the reason of quality problems and direct quality improvement, three new indices Cps, Cpc, and Cpc available in real time are introduced to control the scatters and errors. Finally the feasibility of these indices is proved by an application.
Abstract: Two theorems are presented for constructing array dynamical systems with generalized synchronization (GS) with respect to linear transformations. Two array dynamical systems with GS are introduced based on the theorems. Numerical simulations show that the two systems display complex limit cycle GS and chaotic GS, respectively.
Abstract: Through detail analysis and strict argumentation about two main premises based upon that scholars give the declaration of logical omniscience problem, it was found that the conclusion was made in fact according to two obscure ideas related with the approach to agent study based upon modal logic. From those it is pointed out that, if we admit logical reasoning is in fact an executing process of a studied agent or computer, and if we do not reduce an intentional system as a pure logical system, there surely will not be logical omniscience problem, which is an important conclusion for the vigorous study about agent based upon modal logic.
Abstract: Industrial research for improving the solidification structures of billets with the Electric Pulse Modification (EPM) technology was carried out in Anshan Iron and Steel Group Company. The experimental steel is 09CuPCrNi. The billet size is 150 mm×150 mm. Experimental results show that the solidification structure of the billet was fined obviously by applying electric pulse on the molten steel in tundish. The length of columnar dendrite and the space of primary dendrite of the billet with EPM treatment is much smaller than that of the untreated billet. The zone of the equiaxed grain in the center of the billet is increased. The central shrinkage cavity was eliminated. The mechanical properties of the finished product satisfy the technical standards.
Abstract: The effects of adsorption duration, adsorption pressure, column length and feed flowrate on the presure swing adsorption (PSA) process of the miniature separation of oxygen and nitrogen were simulated mathematically. The evolvement of the profil of oxygen concentration along the column was predicted. The simulating results show that the miniature PSA process is a kind of short-time cycles, and the higher the adsorption pressure, the longer the shock profile of oxygen concentration passes through the column. With the increasing of feed flowrate, the length of the column must be extended. It is founded that a short column will cause a decrease in oxygen purity in product and the cyclic steady-state is achieved after about 15 cycles. If the high purity oxygen is expected, the shock profile must not pass through the adsorption column. The mass transfer has important influence on the performance of the miniature PSA process and the local equilibrium approximation can not be applied.
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
