Abstract: According to engineering-geological conditions and mining sequences, the limiting equilibrium theory and numerical simulation were used to study the stability of East Open-pit Slope in Daye Iron Mine, China. By analyzing the changes of the stress, displacement field and plastic zones, the stability of the slope was inspected. The results indicate that the safe factor is greater than 1.25, illustrating the slope in a stable state. On three sectional profiles, the distributions and changes of the stress, displacement and plastic zones induced by excavation are ap- proximate. The back filling at the slope bottom not only enhances slope stability, but also provides the safe overlay which is needed in underground mining.
Abstract: Based on engineering practice and amounts of geological survey analysis, combined with the theory of engineering geology and the principle of large deformation mechanics, the compound deformation mechanics mechanism of soft rock with tiny swelling and structure-deformed type (JS) was affirmed in the roof of coal roadways in Zhenchengdi Coal Mine, China. FLAC was used to analyze the mechanical measures and optimize support parameters while the deformation mechanical mechanism of soft rock transforming from compound to simple. The results of field experiments showed that the compound supporting of bolt-wire mesh-anchor has successfully solved many difficult problems for years in coal roadways of Zhenchengdi Coal Mine.
Abstract: A machine learning algorithm——Support Vector Machines (SVM) was introduced into the field of soft rock engineering supporting design. An improved Support Vector Machines Regression (SVR) algorithm was presented to meet the needs of this problem and the corresponding calculation code was programmed, It is concluded that a high degree of prediction accuracy and a very good generalization can be obtained with small quantity of learning samples using this algorithm from the calculated results of an engineering instance. It can avoid the overfitting problem of artificial neural network (ANN) which brings the difficulty in determining the parameters of ANN. It facilitates users to a great extent and provides a new way in the supporting design of similar engineering.
Abstract: The regional geological fault was determined by the geo-dynamic zoning method. Based on analyzing the relations between the influential factors and the dangerousness of coal and gas outburst, a muti-factor model of pattern recognition was established. The pattern recognition method was applied to predict the regional hazard of coal and gas outburst. Panyi mining area was then divided into the coal and gas outburst dangerous area, threatening area and safe area to assess and predict the hazard of coal and gas outburst. The prediction accuracy of gas in coal and gas outburst was improved.
Abstract: A simple statement about dust hazard and the mechanism of roadway dust induced by haulage loads in an open pit were analyzed. Based on the theoretic results, a concept for eco-typed dust control and a recipe of roadway dust suppression were introduced. The dust suppressor characterized by adhesion, moisture-absorption and anti-evaporation is completely different from those in conventional ways. An extensive experimental simulation and commercial test were carried out and the results show that the suppressor can meet the requirement of roadway dust suppression in an open pit and other similar sites because of its excellent dust suppression effects such as adhesion, agglomeration, moisture absorption and anti-evaporation and pave-concretion, and self-adaptive to natural environment, simple preparation technology, rational comprehensive cost and high specific performance.
Abstract: A strain of microalga that has a strong ability in the utilization of organic compounds was isolated from Qinghe River in Beijing and identified as Chlorella sp. The effects of nitrogen compounds and carbon-to-nitrogen mass ratio on the growth of this isolated Chlorella sp were investigated in batch cultures. Using glucose as the sole carbon source, both potassium nitrate and urea could be used as the sole nitrogen sources to support the continuous growth of Chlorella sp, respectively. When ammonium chloride was used as the sole nitrogen source, the growth of Chlorella sp could be apparemly inhibited by the rapid decrease in pH of culture solution. When glucose and potassium nitrate were used as the sole carbon and nitrogen sources, respectively, the growth ofChlorella sp increased with the increase of carbon-to-nitrogen mass ratio in range from 5 to 20, and the maximum OD680nm of 73.8 was obtained.
Abstract: The species distribution and transformation characteristics ofpolysilicic acid in the presence of acetic acid were investigated by chemical Si-Mo assay analysis. The experimental results showed that in the acid condition the polymerization rate decreased in acetic acid media, and the contents of species Sia and Sib were increased. This further indicated that when the acetic acid compound existed it could slow the growth rate of the particles of polysilicic acid, but total species distribution and its transformation model ofpolysilicic acid did not change.
Abstract: The effect of particle morphology on the operating parameters of a circulating fluidized bed boiler such as sphericity and size distribution in dense and dilute phases was analyzed, and the combustion behavior of chip-like anthracite was studied through the measured operating parameters. The results showed that particle morphology has huge impact on the average suspension density and partical size distribution in the dense bed and dilute bed of a furnance, and might be the direct reason of the flucluatons of furnace temperature and elutriation.
Abstract: A hybrid method (MCHF method) combined the Monte-Carlo method and the heat flux method was presented to analyze radiative heat transfer in a three-dimensional enclosed rectangular. The special heat flux parameter distribution and the temperature distribution of the rectangular were analyzed by comparing the computational results with exact results by the classical zone method. The analysis showed that the results calculated by the MCHF method are reasonable with excellent accuracy and efficiency, thus the MCHF method has a strong application value in radiative heat transfer in industrial furnaces.
Abstract: The amount, size distribution and style of microinclusions in non-oriented silicon steel sheets with or without calcium treatment were studied by metalloscope, image analytical meter, scan electron microscope and transmission electron microscope. The results show that microinclusions in the range of 0.1 to 0.4 μm influence the core loss of silicon steel sheets greatly but the style ofmicroinclusions has less influence.
Abstract: On the basis of analyzing nozzle clogging, the effects of feeding speed, the amount of Ca-Fe cored wire during Ca-treatment and nozzle diameter on the castablity of billet continuous casting for low-carbon low-silicon Al-killed steel were studied by an orthogonal test in line with the on-site condition of No.3 Steelmaking Shop of Ma-Steel, China. The results showed that increasing the feeding speed, the amount of Ca-Fe cored wire and the diameter of the tundish nozzle can prevent blockage. After adopting these parameters proposed, 8-10 heats could be cast in sequence, and the surface quality and internal quality of the billets are satisfactory.
Abstract: The cleanliness of IF steel slabs produced by the BOF-RH-CC process in different casting stages was investigated. Due to reoxidation at the casting beginning period, the[C],[O]T,[N] contents of the first slab are higher than those of the slabs in other stages, and a few big size Al2O3 clusters exist in the first slab. The non-metallic inclusions in the normal slabs at the casting middle period is mainly small size Al2O3 blocks (≤ 30μm) and a few small size Al2O3 clusters (≤ 40μm). The transition and end slabs have still mainly small size Al2O3 blocks, but appear few big size (≥ 100 μm) composite inclusions.
Abstract: The chemical composition and microstructure near surface net cracks of continuously cast slabs and hot rolled plates were analyzed. The results showed that there exist Cu and Cr near the cracksand the cracks propagate along the vicinities of grain boundary. The reason of net cracks formation can be concluded that abrasion of the mold coating causes liquid copper to penetrate into the Fe matrix along the grain boundary ofaustenite and enriched copper will deteriorate the hot ductility of steel tremendously, on the basis of which, some measures to control surface net cracks were put forward.
Abstract: The effect of hydrogen ion implantation on the microstructure ofODS ferritic steel was studied by means of ion implantation at room temperature and in-situ observations in a low voltage electron microscope. The results indicated that a certain amount of (Fe,Cr)2O3 phases existed in the original ODS alloy. They did not change obviously after hydrogen ion implantation at room temperature. During heating the specimen implanted with hydrogen ions, however, the (Fe,Cr)2O3 phase dissolved gradually and the composition of the residual (Fe,Cr)2O3 phase changed too. On the contrary, the microstructure of the specimen which was not implanted with hydrogen ions did not changed obviously during heating, meanwhile, (Fe,Cr)2O3 phase did not dissolve.
Abstract: Industrial experiments of Q235 plain carbon steel by Accumulitive Roll-Bonding (ARB) process were carried out. The effects of deformation temperature, reduction (the max reduction 98%) and cyclic roling pass on the microstructure and mechanical properties of the steel were investigated. The results showed that a steel with ultrafine grains and higher mechanical properties could be obtained on a plain hot rolling mill by ARB process. It was also proved that the interracial microstructure was continuous and homogeneous because of the same material rolling.
Abstract: A coating was prepared on 0Cr13Ni5Mo stainless steel by air plasma spraying with a kind of molybdenum base alloy powder which contains Si, B, Cr, W, Mo, Ni etc. as the plasma spraying powder. It was proved that the Mo-base alloy coating fabricated by air plasma spraying has homogenous microstructure and contains metal glass and nanocrystals by X-ray diffractometer, SEM, TEM and Potentionstat/Galvanostat Model 273. The coating has high hardness and the highest micro-hardness can reach 1 426.9 HV. The porosity is about to 3.1%. Experimental results also show that Mo-base amorphous and nanocrystalline alloy coatings can appear a passivation phenomenon in a 3.5% NaCl solution with Icorr(R)=6.459μA·cm-2 and E (I=0)=0.869 mm·a-1.
Abstract: The effects of the thickness and deposition rate of Ta seed layer on the anisotropic magnetoresistance (AMP.) and coercivity ofTa/Ni65Co35 bilayers were investigated. The results showed that △ρ/ρ of Ta/Ni65Co35 bilayers could be improved at a certain thickness or higher deposition rate. The coercivity of Ta/Ni65Co35 films increased with the use of Ta seed layer. But the effect of the deposition rate on the coercivity of Ta/Ni65Co35 films was not significant.
Abstract: A TiO2 catalyst doped by Pb2+ was prepared by the sol-gel method and characterized by DRS and FS. The experimental results showed that Pb2+ strengthened the TiO2 fluorescence apex, the absorbance band edge moved in the red direction, and the absorbance strengthened obviously both in the UV range and in the visible range. Compared with Ag-TiO2, Bi-TiO2 and TiO2 films, the Pb2+-doped TiO2 thin film has the highest photocatalytic activity by studying the degradation of methyl orange under UV-ray, which is an effective way to increase the photocatalytic activity.
Abstract: The effects of high energy shear broken time on the settlement curve, mean grain size, BET surface area and apparent density of WO3 and W powders were studied. The powders after and before being broken were observed directly by TEM and SEM. The results showed that by the new-type high energy shear milling micrometer WO3 powder can be broken, and bridged particles in ultrafine W powder can be cracked, with the apparent density of W and WO3 powders doubling, but without much influence on their specific surface area.
Abstract: When the leadframe made of 4J42 alloy is brazed to the brazing zone of an alumina substrate using an AgCu28 filler in ceramic DIP production, the liquid filler often flows onto the surface of the leadframe after brazing, and the quality of finished products is influenced greatly. These problems are related to improper brazing process for ceramic package. The effects of brazing temperature, hold time and filler quantity on the flow of an AgCu28 filler were studied under factory and laboratory conditions. The results showed that the flow of the AgCu28 filler mostly depends on the hold time at the temperature above the melting point. Three optimum brazing processes in which the flow of the filler could be avoid were found:firstly held at 700℃ for 5 min and then held at 800℃ for 4 min, secondly held at 900℃ for 10 min, and in the last process, the graphite boats passed through the zone of 810℃ at the speed of a boat every 4 min in the manual way or the hold time at the temperature above the melting point is limited in 5 min by adjusting the belt speed of the conveyer-type continuous furnace.
Abstract: By means of the cyclic voltammograrn, the effects of upper potential and activation mode on the catalytic activity of two Pt/C catalysts prepared by the sulfurous route and the stannous method for methanol electro- oxidation were investigated. It is showed that different catalysts obtains different optimistical upper potentials in step-by step activation by changing upper potential. At the optimum upper potential, one-step activation is more effective than step-by step activation for the stannous Pt/C catalyst. Different activities obtained under different activation modes indicates that Pt is transformed into different states during different activation processes which endow the resultant catalyst with the distinct adsorption capability and rate for anions and water.
Abstract: A synthetic technology of water-soluble alkyd resin was summarized. The traditional alkyd resin was modified by the modifier which was consisted of styrene monomers and methyl methacrylate monomers. Some capability tests of the modified resin were investigated. The results showed that the modified resin attains the same dryness level as the traditional alkyd resin.
Abstract: The function of stage-cooling in flatness control becomes more important than ever before by many examples in factories. On the base of the convection heat transfer between the working rolls and the coolant fluid of the aluminum mill 1400F, the optimum values of convection heat transfer were found through orthogonal experiments and proved to be optimal by numerical simulation. The factors in orthogonal experiments arranges as the viscosity, the speed, the temperature and the spraying angle of coolant fluid in the order of importance.
Abstract: In order to produce many kinds of products and improve products quality and rolling efficiency, a set of accelerated cooling system with the advanced technology of plates after rolling was designed based on the condition of the plate rolling plant of Wuhan Iron and Steel Corporation, China. The water supply technology by frequency conversion, the optimized distribution technology of water quantity and the high-density laminar flow technology were used in the system. High performance controllers from Siemens were also applied in the system. The system had reliable construction, integrated functions and good control precision, and was successfully used in the plate rolling plant of Wuhan Iron and Steel Corporation.
Abstract: The basic parts of the distance measurement of a pulse echo system were described. The study of lower noise electronic circuits was emphasized in the ranging system. A new kind of emitting and receiving circuit was designed with an isolated switching circuit to form different switching times and isolated current circuits, and the routing of the electronic noise from the emitting circuit to the receiving circuit was totally isolated. The new principle of "energy ball" was proposed to increase the signal-to-noise ratio distinctly, and the ability of receiving echo signals is more stable in the normal power consumer. Also a software filter in the digital data base of the pulse echo was introduced in the application to intelligent noise reduction.
Abstract: The experimental apparatus for the separation of oxygen and argon was established based on the kinetic adsorption of carbon molecular sieves. The effects of PSA cycle, rinse-ratio and adsorption duration on the performance of adsorption processes were investigated. The experimental results show that to incorporate the rinse step can increase greatly the concentration of oxygen in desorbed gas. For producing high purity oxygen, the optimum values of the rinse-ratio and adsorption duration should be about 0.4 and 60 s respectively. Under this condition, the oxygen purity up to 99.4% is obtained for the 42% recovery with the feed gas mixture of 95% oxygen and 5% argon.
Abstract: In order to reach the aim of increasing the integrated benefit from mines to blast furnace works, an exclusive software for optimizing iron concentrate grade was developed. The optimum iron concentrate grade was established by the method of fuzzy integrated evaluation. When iron concentrate grade, cost and pig iron price change the software can be used for evaluation of the total benefit of mining, mineral processing, sintering, palletizing and ironmaking, and the output of pig iron. Based on the mathematical models of mineral processing, sintering, palletizing and ironmaking, the software was used for optimization of the iron concentrate grade in Shuichang Mine, China. The optimum iron concentrate grade in Shuichang Mine is TFe 67.92%.
Abstract: A time-delayed feedback control method based on the fuzzy genetic algorithm was proposed for chaos control. The fuzzy genetic algorithm was used to optimize parameters of the time-delayed feedback control method. The results of simulation for controlling a chaotic Lorenz system to a fixed point and a period-2 orbit show that the new algorithm has many advantages such as fastness and strong anti-interference.
Abstract: A control system was proposed to improve braking distance and stability by the integrated control of yaw-moment control and active front steering. A compound controller with forward and feedback controllers was presented, and the parameters of the feedback controller were obtained by the optimum control theory. Then the output parameters of the controller and braking forces were regulated in order to shorten braking distance. The control method was verified by simulation that stability and braking distance are optimized.
Abstract: The proposed off-line handwritten Chinese character recognition system was composed of a feature extraction module and a recognition module. In the feature extraction module, the orthogonal Zernike moments and the elastic mesh technique were combined to get fusion features, which present the global and local features of handwritten Chinese characters and have great discriminative capability. As for the classification module, one approach that is very similar to the neural network classification strategy was used with the Least Square Vector Machine (LSSVM), which not only has the excellent performance of generalization and recognition accuracy, but also can solve the multi-classification issue effectively. Experimental results indicated that the proposed method could get good recognition results.
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
