Abstract: Three shortcomings and two errors of Zadeh's fuzzy set theory were analyzed and proved, and a new fuzzy set theory, C*-fuzzy set theory, was proposed. The new C*-fuzzy set considers the relationship between fuzzy sets and represents the relationship with relativity. It overcomes all the errors and shortcomings of Zadeh's fuzzy set theory:it correctly reflects different kinds of fuzzy phenomena in the natural world; set complement exists on it; it has uniform calculating formulas for membership; it satisfies all formulas of the classical set theory and is consistent with classical and normal thinking, logic and concepts.
Abstract: Based on the origin and nature of in situ stress, a mathematical model was built up. The regression equations of the six stress components were obtained according to measured results and the principle of multivariate nonlinear regression analysis. These equations are important for understanding the feature of the initial stress field in an area.
Abstract: Based on analyzing the principle of continuous demulsification of liquid emulsion membrane by a centrifugal pulse electric field, a set of centrifugal pulse electric field continuous demulsifier was designed and fabricated with vertical cylinder insulated electrodes, which was used in laboratory. The effects of various factors on continuous demulsification were studied in extracting Cu2+ experiment by the liquid emulsion membrane composed of M6401-L113B-kerosene-H2SO4 or Lix984N-L113A-kerosene-H2SO4 from waste water. It is shown that the continuous demulsification by the centrifugal pulse electric field was successful. And the continuous demulsifying effectiveness of a centrifugal pulse electric field is better than that of a pulse electric field.
Abstract: Influencing factors on Ni bioaccumulation by Synechcoccus were studied. The equilibration time of Ni bioaccumulation was about 80 min in aqueous solution. The bioaccumulation quantity reached a maximum when the mass ratio of Ni to Synechcoccus was between 16%-18%, and increased with the increasing ofpH. The optimum pH was 9-10 because high pH would lead to precipitation of Ni(OH)2. The bioaccumulation quantity was also influenced by temperature and illumination intensity and the optimal condition was 35℃ and 3000 lx. The bioaccumulation of nonliving algae was lager than that of living algae.
Abstract: A grid form of inner cover in a bell-type annealing furnace was put forward to resolve the problem about low vertical stiffness of traditional ones. The heat transfer efficiency of the inner cover was compared with traditional ones' via theoretical calculation of influencing factors on heat transfer efficiency such as convection heat exchange coefficient and heat transfer area. It was proved that the grid inner cover could improve the heat transfer efficiency and throughput of the bell-type annealing furnace.
Abstract: Through numerically simulating the temperature field in a multi-heat-source synthetic SiC furnace, the temperature distribution at characteristic points was obtained, and the dynamic laws of thermal gradient and thermal flow intensity were put forward. The heat and mass transfer law in multi-heat-source synthesis of silicon carbide were revealed. It was shown that due to the superposition effect of thermal fields and the shielding action of furnace cores, the SiC output of the multi-heat-source furnace increased by 48.1% compared with that of an Acheson singleheat-source furnace, the highest grade SiC increased by 30%, and the consumed energy reduced more than 10%. In addition, the frequent spouting was diminished, and the furnace was become more productive and safe.
Abstract: The precipitation behavior of inclusions containing Ti in liquid steel and during solidification ofa Tibearing non-quenched and tempered steel was investigated by experiment and thermodynamic calculation. The resuits showed that the size and morphology of inclusions in the non-quenched and tempered steel could be controlled by adjusting the contents of O, Al and Ti, and fine and disperse non-metallic inclusions might be obtained as the nuclei for intra-granular ferrite, which could refine grains and improve the strength and toughness of the steel.
Abstract: High temperature properties of continuous casting high carbon steels were measured by tensile tests with a Gleeble 1500 system and two embrittlement temperature regions of region Ⅰ and region Ⅲ were found. The results indicated that the cause of embrittlement in region I was the existence of liquid film along dendritic interfaces, and the embrittlement in region Ⅲ was caused by precipitation of proeutectoid ferrite film along austenite grain boundary. AIN precipitation at the full austenite grain boundary would worsen the ductility of the steels.
Abstract: The rust layer of a weathering steel was obtained by using dry-wet circle test and then analyzed by Electrochemical Impedance Spectroscopy (EIS) with an established equivalent electrical circuit. The results indicated that the technique of EIS test could be used to analyze characteristics of the inner rust layer of the weathering steel effectively. The combination of dry-wet circle test and EIS test would be applied to evaluate the weathering steel's corrosion-resistant performance rapidly and reasonably.
Abstract: The main specification and process route during production and exploitation of D36 high-strength ship plate steel in Xunyu Iron and Steel Co., Ltd. were introduced. During the exploitation of D36 high-strength ship steel, thickness deviation changing and bad plate weldability were risen by less functional parameters of the rolling mill. The over-all properties and weldability of the D36 plate were preferably solved and improved by the adjustment of depressed allocation, the translation of product objective thickness and control range, and micro-Ti treatment.
Abstract: The basic theory of the Enhanced Assumed Strain Modes (EASM) and the corresponding constitutive relationship as well as finite element formulation were addressed. In order to overcome the deficiency of the original method proposed by Simo, i.e., the Hourglass modes appear in the case of compression, algorithms for updating stresses and interior variables were developed by using an optimal post-process technique. It were proved from numerical results that the improved EASM is of good stability especially in the case of large compressive situation being involved.
Abstract: A boundary value problem of governing equations for the concentration of crystal growth is solved in the two-dimension steady state considering the effect of uniform convection field. The differential equation is numerically discretized into a system of linear algebraic equations by using the finite difference method. In order to improve computational efficiency, the system of linear algebraic equations is decomposed to several sub-systems. The result of numerical simulation shows that the concentration of crystal growth in steady state presents oscillating attenuation along the direction of dendrite growth in the action of uniform convection field.
Abstract: Electric pulse was used to treat liquid P510L steel for modification and macrostructures. The microstructures at different electric pulse parameters were observed. It was showed that crystal grains were refined apparently and dendritic crystals were reduced obviously by means of air cooling. Pearlitic crystals in P510L steel were found after treated by electric pulse, and the distance between pearlitic crystals and lamina was shortened remarkably.
Abstract: A thermal model developed by means of the finite difference method was adopted to predict the temperature distribution across the thickness of steel plates. The accuracy of this model was validated by the commercial finite element package FEMLAB. The heat transfer of hot plates was considered in this model when cooled in air, laminar water flow, and turbulent water flow. Furthermore, this model coupled the measured thermal physical parameters so as to improve its accuracy.
Abstract: The precipitation temperature range and quantity in equilibrium phases of three P/M superalloys, René95, René88DT and зп741нп, were systematically calculated by using a thermodynamic calculation method and the relevant superalloy database. The calculated results show that the three alloys have the same major phases, such as γ,γ' and MC, M6C, M23C6 carbides. The quantity of carbides in René95 is more than the others. The γ' precipitation temperature of зп741нп is higher and the γ' amount is more than that of René95 or René88DT. The liquid segregation behaviors of the three alloys were compared and discussed.
Abstract: The densification of nanoscaled W-Cu powder was investigated through measurements of the shrinkage kinetic curves in hot pressing and hydrogen sintering and compared with that of nanoscaled W powder and traditional Cu powder. The resulted alloys were subjected to hot compression tests at 300℃ and 500℃ to obtain their stress-strain curves. It is indicated that the temperature corresponding to the highest shrinkage rate of nanoscaled W-Cu powder is 980℃ in hydrogen sintering. After sintering at 1200℃, the mean grain size of W phase is less than 2 μm, and the relative density of the alloy is 97%. In hot pressing, however the corresponding temperatures is 930℃. The mean grain size of W phase in the hot pressed alloy from nanoscaled W-Cu powder is 0.5μm at 1 200℃, and its relative density is 98%. The results of hot compression tests at 300℃ and 500℃ showed that the high-temperature strength of the ultrafine grained W-Cu alloy is higher than that of the alloy sintered from nanoscaled W powder and traditional Cu powder.
Abstract: The coating was prepared on 316L stainless steel by air plasma spraying with a kind of iron base amorphous alloy powder which contains C, Si, B, Cr, W, Mo, Ni, Fe etc. as the plasma spraying powder. The crystal configuration of the coating was inspected with an X-ray diffractometer, the microstructure observed by SEM and TEM, the hardness and elastic modulus measured with a micro-sclerometer and a triboindenter; and the size ofcry- stallites in the coating calculated by Scherrer's equation. It is proved that the Fe-base alloy coating fabricated by air plasma spraying has homogenous microstructure and contains metal glass and nanocrystal at the same time. The experimental results show that the coating is uniform, dense and well combined with 316L stainless steel, with high hardness and elastic modulus.
Abstract: The Fe-Si3N4 powder, synthesized by flashing combustion process, is considered as a new-style raw material for the high temperature condition, but its fine performance has not been recognized. The Fe-Si3N4 powder less than 74μm was made into samples of 50 mm in diameter and 80 mm in height under a molding pressure of 250 kN. The apparent porosity, bulk density and strength resistance of the samples were measured by drilling a cylinder of 36mm in diameter and 50mm in height in the samples, which were sintered at 1 500℃ for 3 h under the air condition. SEM, EDS and X-ray diffraction were employed to study the sintered samples. All the results showed that with Fe-Si3N4 as the raw material and no subsidiary materials, a refractory on the base of Fe-Si3N4 could be prepared at low temperature under the air condition with the combining action of Fe3Si, which originated from the material and was made by the reaction between Fe and Si3N4.
Abstract: Isochronal plots and a three-parameter linear viscoelastic model were used to characterize the stressrelaxation properties of PVA-H prosthetic nucleus and to analyze the influence of swelling ratio and initial PVA content upon the stress-relaxation properties. The results ofisochronal plots showed that PVA-H prosthetic nucleus followed a linear viscoelastic mechanical property. The three-parameter linear viscoelastic model can simulate the viscoelastic property of prosthetic nucleus well with the fitness more than 0.96. It can be seen from the analysis of parameters in the model that the increase of the swelling ratio will greatly increase the speed of dissipated stress of the prosthetic nucleus, and does not have too much influence on the total dissipated stress; but the increase of the initial PVA content will decrease both the speed and the total of the dissipating stress.
Abstract: Conducting polyaniline depended on environmental temperature. In order to determine the effect of temperature on polyaniline, polyanuline was electrosynthetized by the cyclic voltmmetric method in sulfuric acid. The thermal decomposition temperature ofpolyaniline was determined to be 285.7℃ by TAG. The thermal lifetimes were tested by the isothermal TG for regression of the lifetime equations at various weight-loss ratios of 5%, 7% and 10%. IR spectra showed that the characteristic absorption shifted to a higher number with increasing temperature, which was caused by the decreasing conjugate structure of polyaniline.
Abstract: A looper system possesses strong nonlinear, strong coupling, uncertain and multi-constrained features. For improving automatic gauge control accuracy and quality in hot strip mills, an appropriate mathematical model ought to be built so as to complete the decoupling control of loopers' height and tension system. According to the little signal theory, whole transferring functions of the looper system were presented by analyzing its coupling process and practical data. The control strategy of prediction for a linear model based on BP-PID was introduced to improve control effect and to decouple the looper system. The simulated results showed the effectiveness of this algorithrn and after decoupled, the loopers' control performance got much better.
Abstract: A real-time simulator of Automatic Gauge Control (AGC) for hot-rolling mill based on Digital Signal Processors (DSP) was proposed. The models of the hydraulic cylinder for Automatic Position Control (APC) and the deformation area of each stand were built. The simulator was performed by using a parallel processing based dynamic simulation of the characteristics of the strip and of the stands which were coupled by the rolled material, and exchange data with the AGC controller of a computer control system through reflective memory network in a real-time mode. It could be used for developing and real-time testing AGC control strategies in off-line state.
Abstract: In order to improve product quality and rolling efficiency, a new set of accelerate cooling system of plates after rolling was designed for the plate rolling mill of Wuhan Iron and Steel Corporation. The system integrated many kinds of advanced control strategies and control models. High performance controllers of Siemens were also applied in the system and fully automatic control was realized. The application results showed that the cooling system had integrated functions and good control precision, and product quality was improved greatly.
Abstract: In order to investigate the elongation assignment of steel plates between a tension leveler and a skin pass mill for the Acid-Refined 2030 in BaoSteel of China, the testing of mechanical properties was designed at different elongation assignments and was analyzed from many aspects. The elongations of the tension leveler and the skin pass mill are presented.
Abstract: A new method was proposed to analyze the character of a soil-water system by measuring the complex permittivity with high-frequency microwave, and an environmental protecting sensor was designed. In the design, the single-ended reflex coefficient method was used and porous ceramics was made into the permeation cell. This paper described the design, production and date processing technique.
Abstract: Based on the heat pump assisted fluidized bed grain drying equipment developed recently, a experimental analysis of the heat pump was performed. The influencing factors and their effects on the temperature of air outflow from the condenser and the coefficient of performance of the heat pump in a drying experimental system were gained from the experimental results. Coupled with corresponding theoretical analysis, it was found out that the higher the flow quantity through the evaporator and the lower the outlet temperature of the condenser; the better performance the heat pump can achieve. According to those results, a plan to improve the heat pump drying system was set up, and the performance quality of the improved heat pump and its corresponding economic evaluation of the drying system were predicted. It was shown that the improved heat pump can achieve its COP up to about 3.856, and the cost drying reduced sharply.
Abstract: With the non-breakable feature in steel product making, an integrative scheduling model was presented. The object was to minimize the flow span time and the wait time between working steps. One furnace was counted as one working piece and several furnaces were regarded as one cast. By using the improved genetic algorithm, a cast scheduling table and a subsequent Gantt chart described the results. A group of typical testing data validated the results.
Abstract: According to the related policies and codes of China and the factors of ecological condition and economic structure in Tonghua area, five kinds and four layers of twenty-four indexes were chosen to construct an index system of sustainable development degree in Tonghua area. The method of expert point rating was adopted to establish a weighted array of the multi-index integrating measurement model so as to forecast and evaluate the effect of iron and steel industry in Tonghua area on ecological condition and social economy. The sustainable development degrees in Tonghua area in 2010 and 2020 were evaluated quantitatively and the rationality of all indexes was verified.
Abstract: A noise reduction method in nonlinear time series based on phase reconstruction and manifold learning was proposed. In a high dimensional phase space, the inherent features of time series were exhibited as a low dimensional nonlinear principal manifold. The noise was reduced by the reconstruction with the underlying manifold which was obtained through a local tangent space alignment algorithm. Different from the existent noise reduction methods in nonlinear time series, the method based on principal manifold learning emphasized more on the global structure of time series. The results of numerical simulation proved that the method could remove the Gaussian white noise in nonlinear time series effectively.
Abstract: Based on the Silnikov theorem, a theorem that confirmed the existence of Smale horseshoes sense chaos was set up. Using the theorem, a new kind of quadratic chaotic system could be constructed, which has a unique equilibrium point. A numerical simulation example demonstrated that this system could have chaotic attractor. In particular, the method could be used to generate other quadratic chaotic systems.
Abstract: In order to study contradictory problems ofmultilayer multidimensional complex systems, based on the concept of n-dimensional matter element extension set, the concepts of multilayer multidimensional matter element system extension set and its positive field, negative field, zero boundary and its extension field as well as its stable field were given. The properties, intersection and union operations of multilayer multidimensional matter element system extension set were also discussed.
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
