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Information & Control

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Vignetting Influence on Accuracy of Temperature Measurement for CCDbased Pyrometer and Correction Method ZHANG Yuzhong， HU Zhengwei， MENG Hongji， XIE Zhi 2014, 35 (5):  609-612.  DOI: 10.12068/j.issn.1005-3026.2014.05.001 Abstract ( 767 )   HTML   PDF (928KB) ( 758 )   Due to the existence of vignetting in the CCDbased pyrometer， there is serious photometric distortion in temperature field， resulting in the severely decreasing of the temperature measurement accuracy. So， a mathematical model for temperature distortion based on theories of radiation thermometry and geometrical optics was built， and the influence of optical system parameters on the accuracy of temperature field measurement was analyzed as well. Based on the sparsity of neighborhood gray gradient distribution (NGD)， a method for the calibration of vignetting coefficient was also proposed. Compared with the calibration method using a integrating sphere， its maximum absolute error for vignetting estimation is only 0052， and the effectiveness of this calibration method is validated by the experiment of temperature field correction for casting billets. References | Related Articles | Metrics

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Parameter Identification of Heat Transfer Model for Continuous Casting Billets Based on Chaos Particle Swarm Optimization YANG Jian， MENG HongJi， JI Zhenping， XIE Zhi 2014, 35 (5):  613-616.  DOI: 10.12068/j.issn.1005-3026.2014.05.002 Abstract ( 665 )   HTML   PDF (864KB) ( 653 )   Due to the complexity and nonlinearity with a partial differential equation， an identification method based on chaos particle swarm optimization (CPSO) was presented. Based on the combination of the measured shellthicknesses by nailshooting at different positions and the measured surface temperatures outside the secondary cooling chamber， parameters related to the heat transfer coefficients of secondary cooling and the effective conductivity were determined. Finally the model was verified as the difference was within the range of ±13℃ between the calculated surface temperature by online calculation and the measurements at the exit of secondary cooling chamber. The verified model was applied to the optimization and dynamic control of secondary cooling. References | Related Articles | Metrics

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Based on Fuzzy Adaptive Control of Model Predictive in Slurry Neutralization Process JIA Yao， ZHANG Liyan， CHAI Tianyou 2014, 35 (5):  617-621.  DOI: 10.12068/j.issn.1005-3026.2014.05.003 Abstract ( 632 )   HTML   PDF (816KB) ( 694 )   Nickel hydroxide and cobalt hydroxide slurry neutralization process exist large hysteresis timevarying nonlinear characteristics. When using the existing neutralization process closed loop control methods in the actual application， if the system was affected by random disturbance， then the pH value would deviate from the target value， which would influence on the performance of the subsequent slurry precipitation process， reducing the nickel hydroxide and cobalt hydroxide product quality. The forecast model and fuzzy adaptive control method were combined in order to achieve industrial process control requirement for the pH value. It was demonstrated by the successful application of a large nickel hydroxide and cobalt hydroxide smelter in foreign country that the problems such as large hysteresis timevarying nonlinear characteristics in the neutralization reaction process could be effectively solved based on the proposed method， resulting in the stable running of the nickel hydroxide and cobalt hydroxide slurry neutralization reaction process， and the improvement of the recovery rate of nickel and cobalt metals components. References | Related Articles | Metrics

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Pavement Crack Detection Algorithm Based on Subregion and Multiscale Analysis LU Ziwei， WU Chengdong， CHEN Dongyue， SHANG Shibo 2014, 35 (5):  622-625.  DOI: 10.12068/j.issn.1005-3026.2014.05.004 Abstract ( 841 )   HTML   PDF (676KB) ( 789 )   In order to improve the accuracy of highway pavement crack detection， a new type of surface defects detection algorithm was proposed based on subregion and multiscale analysis. Gray， entropy and texture features distribution information were extracted in cracks and the surrounding areas from different scales of images. Feature vectors of parameters containing the direction trend and bending degree were acquired， and the crack location was detected through learning the support vector machine (SVM) and judging the eigenvector. Experimental results demonstrated that the resistance to noise， versatility and detection accuracy were improved effectively by the proposed algorithm in comparison to the other pavement cracks detection algorithms. The ideal crack detection effect was achieved， and the requirements of highway quality inspection were met effectively. References | Related Articles | Metrics

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WellConstrained and UnderConstrained Geometric Constraint Solving Based on Dtree Decomposition CAO Chunhong， WANG Peng， CAO Lige 2014, 35 (5):  626-629.  DOI: 10.12068/j.issn.1005-3026.2014.05.005 Abstract ( 641 )   HTML   PDF (502KB) ( 651 )   A Dtree decomposition algorithm was presented to solve the wellconstrained and underconstrained geometric constraint problems. Firstly， as a preliminary work， a broader range handling strategy was proposed which could unify the special constraints with the ordinary constraints. A transformation strategy was used which could transform the underconstrained geometric constraint problem into wellconstrained geometric constraint problem. Secondly， according to properties of the degree of nodes in the geometric constraint graph， the Dtree decomposition algorithm was proposed， which had a lower computational complexity and the same solution domain compared with the classical algorithm. Finally， according to the regularity of the Dtree decomposition algorithm’s results， a export strategy to numerical constraint solver’s solving sequence was presented. The solving sequence exported by Dtree decomposition algorithm could improve the solving efficiency of geometric constraint solving’s numerical solution. References | Related Articles | Metrics

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Coke Oven Collector Pressure Control Based on Subspace Identification LIU Xinming， GAO Xianwen， MA Yunxia 2014, 35 (5):  630-634.  DOI: 10.12068/j.issn.1005-3026.2014.05.006 Abstract ( 659 )   HTML   PDF (1197KB) ( 645 )   In the light of the characteristics of multivariable， coupling and time variation of coke oven gas collector pressure， a incremental online subspace multivariable predictive control strategy was designed for coke oven gas collector pressure. On the basis of incremental subspace predictive control， rolling window subspace identification method was introduced to design the updating strategy of subspace predictor model， and the online subspace adaptive predictive control was realized. Online subspace identification method was used to identify field data of coke oven gas collecting system and better predicted precision was obtained. State space model of gas collecting system was built based on subspace predictor model. In the condition of considering input constraints， timevarying model and disturbance， the control strategy indicated good control precision and performance for state space model of gas collector pressure. References | Related Articles | Metrics

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Bifurcation and Control of DifferentialAlgebraic Biological Model with Time Delay ZHANG Xue 2014, 35 (5):  635-639.  DOI: 10.12068/j.issn.1005-3026.2014.05.007 Abstract ( 576 )   HTML   PDF (731KB) ( 543 )   Considering the economic theory of public fishery， a preypredator bioeconomic model with time delay was studied. It was showed that transcritical bifurcation， singular induced bifurcation and saddlenode bifurcation would occur with no time delay. Under the condition of zero harvesting， prey and predator would be coexisted. With time delay， there existed two positive equilibrium points. Hopf bifurcation and small amplitude periodic solutions would occur， which caused switching of stability. The state feedback controller eliminated bifurcation phenomenon. By using Matlab software， the effectiveness of mathematical conclusions were verified by some numerical simulations. References | Related Articles | Metrics

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Clustering Dynamic Deployment Strategy Based on Virtual Force in Wireless Sensor Networks JIN Rencheng， WEI Ning， XU Hao， WANG Liding 2014, 35 (5):  640-644.  DOI: 10.12068/j.issn.1005-3026.2014.05.008 Abstract ( 621 )   HTML   PDF (1547KB) ( 669 )   In order to improve the coverage of wireless sensor networks (WSNs)， a dynamic deployment strategy was presented based on virtual force (VF) clustering. Based on VF， the traditional algorithm was divided into two phases by the presented strategy. First phase was to deploy clusters and second phase was to deploy the nodes in same cluster， which could reduce the interference between clusters and improve the coverage of network. The strategy was simulated in binary perceptual model， which showed that the strategy had a faster convergence speed and significant effect of optimization comparing with traditional VPF and VFA algorithm in the environment of a large number of nodes. The coverage of network eventually could reach more than 90% which could meet the requirement of coverage control of WSNs. References | Related Articles | Metrics

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Application of Improved Genetic Algorithm in Gas Dispatching of Iron and Steel Enterprise LI Zhi， SU Fuyong， WEN Zhi， LIU Xunliang 2014, 35 (5):  645-649.  DOI: 10.12068/j.issn.1005-3026.2014.05.009 Abstract ( 578 )   HTML   PDF (356KB) ( 633 )   Byproduct gas is important in iron & steel industry， so a maximum benefit objective model was built based on the analysis of characteristic and relationships of important byproduct equipments. Meanwhile， considering the deficiencies and shortcomings of genetic algorithm， which may lead to the low efficiency of the optimization and local search ability， the mutation process with the movement process of ant colony algorithm was replaced to solve the calculation of the model. The proposed model was flexible in the local searching styles， and easy to combine with other algorithms， Finally， the algorithm was successfully tested by means of PC simulations. By the achieved method， the optimization dispatching model of an iron & steel industry was solved， leading to a better benefit. References | Related Articles | Metrics

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Antarctic IceSheet FreezeThaw Detection Based on XPGR Combined with Wavelet Transform WANG Xingdong， LI Xinwu， XIONG Zhangqiang， LIANG Lei 2014, 35 (5):  650-654.  DOI: 10.12068/j.issn.1005-3026.2014.05.010 Abstract ( 754 )   HTML   PDF (1911KB) ( 821 )   In view of the problem of XPGR (crosspolarized gradient ratio) algorithm existed in the icesheet freezethaw detection， an XPGR combined with wavelet transform algorithm was proposed， which did not depend on the field observations. The proposed algorithm was used in the Antarctic icesheet freezethaw detection by microwave radiometer. That was the processing for the long time series data of XPGR algorithm by the use of wavelet transform model to automatically get the distribution of Antarctic icesheet melting onset date， melting duration and melting end date. The computational efficiency， usability and operability of detecting were improved in the icesheet freezethaw detection because many samples could be automatically selected by the algorithm with certain denoising effect. To some extent， the accuracy of detecting icesheet freezing and thawing was also improved and the goal of Antarctic icesheet monitoring system construction was better achieved. References | Related Articles | Metrics

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Effective Fault Diagnosis Method for Composite Web Services Based on Improved HMM Model YIN Ying， LI Ming， ZHAO Yuhai， ZHANG Bin 2014, 35 (5):  655-658.  DOI: 10.12068/j.issn.1005-3026.2014.05.011 Abstract ( 644 )   HTML   PDF (340KB) ( 1086 )   To address the problem that most of the existing composite Web service models are of low accuracy on fault disgnosis， a novel composite Web service oriented fault diagnosis approach was proposed based on an improved hidden Markov model (IHMM). Firstly， HMM model was trained by using the processed multidimensional feature sequences. In this process， the BWbased methods were not used for parameters estimation， since inaccurate parameters would often resulted in due to the single observation. Instead， a Bayes estimation based method to gain more objective paratemeters was proposed. Finally， the probabilities of different fault types caused by the current feature sequence were computed. The one of the maximum probability was inferred as the ultimate fault type. Experimental results showed that the method was effective and efficent. Due to the high diagnostic rate and the low false rate， it was suitable for realtime fault detection in network environment. References | Related Articles | Metrics

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Mix Strategy Game for Routing Overhead Control in Wireless AdHoc Networks HU Xi， ZHU Qunxi， ZHANG Bin 2014, 35 (5):  659-662.  DOI: 10.12068/j.issn.1005-3026.2014.05.012 Abstract ( 590 )   HTML   PDF (563KB) ( 681 )   To increase the availability and the continuity of routes， nodes need to rebroadcast more RREQ packets during route discovery， hence routing overhead is increased and network scalability is limited. To release afore mentioned problem， the mix strategy game was used to model the rebroadcast of RREQ packets， then a mix strategy gamebased routing overhead control algorithm was proposed. The algorithm received the same PREQ between neighboring nodes broadcast the game and thus the probability of each forwarded PREQ could be determined before they could continue to receive broadcast probability in the case of PREQ meet. The simulation results showed that the routing overhead could be reduced obviously， and the overall performance of network could be improved by the proposed routing overhead control algorithm. References | Related Articles | Metrics

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Evaluation Formula for Communication Network Node Importance ZHANG Xiaojuan， WANG Xufeng 2014, 35 (5):  663-666.  DOI: 10.12068/j.issn.1005-3026.2014.05.013 Abstract ( 824 )   HTML   PDF (346KB) ( 889 )   Node importance evaluation based on removal of nodes and their incident links may change the topology of the network. An improved node importance evaluation method was proposed， in which the global importance is combined. The important nodes could be more accurately measured with the proposed method， especially in satellite networks. In the method， the importance of nodes are not only determined by its location in the network， but also limited by the contribution of its neighboring nodes. The location of the node is determined by its betweenness， and the contribution of the node is impacted by the betweenness and closeness centrality of other nodes. The method was compared with the noderemoval based method in the analysis of advanced research project agency (ARPA) net topology. The results showed that the node importance could be accurately represented by the proposed method. References | Related Articles | Metrics

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SpatioTemporal Trajectory Anonymous Algorithm via Map Matching WANG Lina， PENG Ruiqing， FENG Bo， LI Ye 2014, 35 (5):  667-670.  DOI: 10.12068/j.issn.1005-3026.2014.05.014 Abstract ( 705 )   HTML   PDF (406KB) ( 840 )   The current approach using spatiotemporal trajectory anonymous neglected the influence of the spatial correlation on the trajectory cloaking. To enhance the efforts of privacy， a spatiotemporal trajectory anonymous algorithm via map matching is presented to meet the demand for security of the spatiotemporal anonymity and the spatial correlation. The scheme first makes a candidate matching points set for dummy trajectory points by use of the real road network datasets， and then searches the target match trajectory points based on the anonymous function of temporal and spatial and the heuristic breadth first search. Experiments validate the efficiency of the privacy protection algorithm by use of a real datasets and a tool of spatiotemporal trajectory anonymous via map matching that is designed and implemented based on Android platform. References | Related Articles | Metrics

Materials & Metallurgy

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Experimental Research on Microstructure and Properties of TRB After Annealing ZHI Ying， TIAN Ye， ZHANG Jinlian， LIU Xianghua 2014, 35 (5):  671-675.  DOI: 10.12068/j.issn.1005-3026.2014.05.015 Abstract ( 715 )   HTML   PDF (2087KB) ( 789 )   A series of experiments of annealing for tailor rolled blank (TRB) of CR340 were carried out in order to study the microstructure and properties. The effects of the annealing temperature and time on the microstructure and properties of TRB in the area with different thickness were analyzed， and the reasons of different properties of TRB after annealing were explored. The results showed that differences of the microstructure and properties of TRB were determined by the amount of cold deformation，annealing temperature and holding time. By fitting the experimental data， the corresponding relationship between the yield strength and the elongation of TRB in the area of different thickness and the annealing temperature and holding time， and the function of the hardness and yield strength of TRB after annealing were established，which provide a reference for formulating the annealing processes and controlling microstructure and properties of TRB. References | Related Articles | Metrics

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Analysis of Heat Transfer Coefficients During High Intensity Cooling Processes of Hot Rolled Strips After Rolling JIANG Lianyun， YUAN Guo， WU Di， WANG Guodong 2014, 35 (5):  676-680.  DOI: 10.12068/j.issn.1005-3026.2014.05.016 Abstract ( 701 )   HTML   PDF (1147KB) ( 707 )   To study the difference of cooling intensity obtained between the two technical methods for cooling the hot rolled strips of laminar cooling (intensive cooling) and using pressurized jet of cooling water for ultral fast cooling(UFC)， a numerical calculation method was used to get heat transfer coefficients between the surface of hot strips and the cooling water under different cooling methods and mass fluxes. By comparison of the results some conclusions were obtained: the cooling capacity of the ultrafast cooling is greater than that of the intensive cooling method with the same mass flux. The heat transfer coefficient of the surface of hot strips increases with the increase of the mass flux and after reached to an certain value， it decreases with the increase of the mass flux when using the intensive cooling method. However the heat transfer coefficient doesn’t decrease obviously when using the ultrafast cooling method. References | Related Articles | Metrics

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Process Design and Microstructure Evolution of OneStep Quenched and Partitioned Steel TAN Xiaodong， XU Yunbo， YANG Xiaolong， WU Di 2014, 35 (5):  681-685.  DOI: 10.12068/j.issn.1005-3026.2014.05.017 Abstract ( 800 )   HTML   PDF (1994KB) ( 758 )   The heat treatment processes of a lowcarbon SiMn quenched and partitioned (Q&P) steel were designed and investigated. The microstructures and phase components were characterized and analyzed using SEM， TEM and XRD. Theoretical calculation results showed that the optimum quenching temperature for a Fe021C binary alloy is 290℃ and the maximum amount of retained austenite is 179% (mole basis)， respectively. Process simulation results indicate that the volume fraction and the carbon concentration of the retained austenite in the tested steel are 67%~172% and 102%~148%， respectively. The orientation relationship between the retained austenite and adjacent martensite laths is identified as KS relationship or NW relationship. Fresh martensite forms in all the involved experimental processes. The amount of the retained austenite increases first and decreases after 50s and the carbon concentration of retained austenite rises monotonously with the increase of partitioning time. The optimum partitioning time is 50s. The carbides appear in the martensite laths during the later stage of the partitioning process and result in the decrease of the retained austenite. References | Related Articles | Metrics

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Effects of the Small Amount of Ferrite in Bainite Laths on the Strength and Toughness of High Strength Steels SONG Fengyu， ZHANG Pengyan， WANG Ping， ZHU Fuxian 2014, 35 (5):  686-689.  DOI: 10.12068/j.issn.1005-3026.2014.05.018 Abstract ( 774 )   HTML   PDF (1306KB) ( 614 )   A low cost high strength steel was studied by TMCP processing under different cooling modes， the microstructures and mechanical properties were investigated by the optical microscope， tensile testing machine and shock testing machine respectively. The results showed that the transformation strengthen and insulation treatment in two phase region can bring a small amount of ferrite into the tested steel， in which the original microstructure is mainly lath bainite， that leads to high strength and high shock toughness of the tested steel. Under the similar conditions， the tensile strength， yield strength and yield ratio increase while the elongation and reduction of area decrease with the decrease of the final cooling temperature. References | Related Articles | Metrics

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Roll Shape Calculation of Flexible Rolling for 3D Curved Surface Metal Plates QIU Ningjia， LI Mingzhe， LI Renjun 2014, 35 (5):  690-694.  DOI: 10.12068/j.issn.1005-3026.2014.05.019 Abstract ( 798 )   HTML   PDF (1533KB) ( 677 )   The relationship between the thickness variation of the rolling sheets and the deformation of the rolling for the threedimensional curved surface parts was analyzed by a curved surface flexible rolling method. The distribution of the uneven roll gap and the function of the working roll arrangement in a convex surface flexible rolling were deduced when the rolls bending shape is the circular. The numerical simulation of the convex surface was applied for the flexible rolling according to the formula. By means of a simple algotithm， the global coordinate reduction has been converted into local coordinate one which led to a better simulation results. A small experimental device was developed and typical test parts were obtained. The simulation and experimental results showed that the curved surface flexible rolling method for threedimensional curved surface parts is feasible and practical. References | Related Articles | Metrics

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Physical Simulation of BOF Limestone Particles Blowing via Top Lance TANG Biao， WANG Xiaoming， ZOU Zongshu， SUN Guangqi 2014, 35 (5):  695-699.  DOI: 10.12068/j.issn.1005-3026.2014.05.020 Abstract ( 550 )   HTML   PDF (961KB) ( 671 )   A cold model of BOF limestone particles blowing via top lance was established to investigate the mixing time， powder distribution and penetration ratio in the melt bath. Water， saltcoated hollow alumina particles and vacuumpump oil were used to simulate liquid steel， limestone particles and slag， respectively. The effects of gas flow and the lance position on the mixing time were studied， and the optimum process in the test condition was determined. The penetration ration and the powder distribution were measured under the optimum processing condition. The results showed that the powder penetration ratio increases with the increase of solid/gas ratio and powder particle size. The lance position under the top blowing spray condition slightly lowers to the height of 258mm， botton blowing rate is 20m3/h.Under the laboratory condition， the powder particle size 0212~0380mm are suggested. References | Related Articles | Metrics

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Metallurgical Behavior of Inclusions in TinContaining Ferritic Stainless Steel HAN Jipeng， JIANG Zhouhua 2014, 35 (5):  700-703.  DOI: 10.12068/j.issn.1005-3026.2014.05.021 Abstract ( 641 )   HTML   PDF (1692KB) ( 806 )   The smelting process of the new tincontained ferritic stainless steel was studied based on metallurgical reaction balance under laboratory condition. The yield of tin in the melting process of the stainless steel and the effects of the addition of tin on the microstructure of stainless steels were analyzed. The formation and evolution of inclusions formed in deoxidation process of molten stainless steel were also analyzed. The results showed that the yield of tin was pretty high regardless of its low melting point. The enrichment of tin around the sulfide inclusions was found in scanning electron microscope pictures and it is white in SEM， while it was not found in or around the oxide inclusions. From the metallographic analysis， tin segregated to the grain boundary when its content was higher than 0.3%. References | Related Articles | Metrics

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Inclusions Modification in Die Steel with Magnesium Vapor GONG Wei， WANG Cheng， WANG Haidong， JIANG Zhouhua 2014, 35 (5):  704-707.  DOI: 10.12068/j.issn.1005-3026.2014.05.022 Abstract ( 579 )   HTML   PDF (1382KB) ( 563 )   Wear failure is the most common failure mode for D2 cold working die steels. The wear rate of the steel decreases by reducing the number of the inclusions and by improving the morphology and distribution of them. The granular magnesium was used to generate magnesium vapor at high temperatures， and the vapor was carried into the molten steel by high purity argon gas. The effects of magnesium on nonmetallic inclusions modification were discussed. The results showed that the size of nonmetallic inclusions in the steel were obviously finer with the magnesium vapor flowing into molten steel than that without it. The composition of inclusions changed from pure alumina inclusions or compound of Al2O3 and the oxide of element Cr，Mo and V to aluminamagnesia complex inclusions. The observation of ascast microstructure showed that small inclusions remained in the steel were benefit for grain refining in the process of solidification and phase transitions. References | Related Articles | Metrics

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Experimental Study on Exergy Transfer Coefficient Affected by Cooling Air Volume in Vertical Tank of Waste Heat Recovery DONG Hui， FENG Junsheng， LI Lei， WANG Aihua 2014, 35 (5):  708-711.  DOI: 10.12068/j.issn.1005-3026.2014.05.023 Abstract ( 895 )   HTML   PDF (648KB) ( 649 )   The exergy transfer coefficient formula in sintering moving bed was derived by introducing the concept of the exergy transfer coefficient in the convection heat exchanger and fixed bed into the vertical tank of sintering waste heat recovery. The relevant data of gassolid transfer process under different conditions in sinter bed of vertical tank was measured in homemade gassolid heat transfer experiment device， and the effect of the cooling air volume on the exergy transfer coefficient in sinter bed was investigated. The results showed that the average physical exergy transfer coefficient hex，m increased with the increase of the ore temperature when the cooling air volume was constant. At the same average ore temperature，when hex，m was greater than zero， it increased with the increase of the cooling air volume; when hex，m is less than zero it reduced air cooling exergy value of vertical tank outlet and adversed to strengthen gassolid heat transfer. References | Related Articles | Metrics

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Silver Flotation from Vortex Furnace Fuming Slag of Zinc Vertical Distilling Residue XU Hongjiang， ZHANG Tingan， WANG Jikun， XIE Gang 2014, 35 (5):  712-715.  DOI: 10.12068/j.issn.1005-3026.2014.05.024 Abstract ( 863 )   HTML   PDF (587KB) ( 639 )   In vertical distilling zinc process， the silver bearing in the zinc concentrate feed primarily remained in the distilling residue. The recovery of silver by flotation from the vortex furnace fuming slag of the distilling residue was investigated. The main parameters including pulp pH， temperature， dosage of the collector and frother which affected the rougher flotation performance were studied. Under the optimized roughing parameters， multistage open circuit and close circuit flotation tests were conducted. Best results were obtained using onestage roughing， fourstage cleaning， and threestage scavenging and the dosage of the collector and frother was 800g·t-1 and 350g·t-1， respectively. The grade of the final silver concentrate was 6100g·t-1 with the silver recovery of 86.10%. References | Related Articles | Metrics

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Extract of HighWhiteness Aluminum Hydroxide from Residues of Magnesium Production by Aluminothermic Reduction Szaibelyite DI Yuezhong， PENG Jianping， WANG Yaowu， FENG Naixiang 2014, 35 (5):  716-720.  DOI: 10.12068/j.issn.1005-3026.2014.05.025 Abstract ( 827 )   HTML   PDF (952KB) ( 690 )   The vacuum aluminothermic reduction process can produce magnesium metal and the reducing residue contains rich 12CaO·7Al2O3. The reducing residue can be solved by a mixture solution of sodium hydroxide and sodium carbonate. The filter residue is rich boron stuff and the filtrate is a solution of sodium aluminate which can be decomposed by CO2 to obtain aluminum hydroxide. In present work the effects of leaching temperature， time， NaOH concentration and Na2CO3 concentration on the leaching rate of alumina were investigated systematically and the performances of aluminum hydroxide obtained were detected with the reduction residue as raw materials. The results showed that the alumina leaching rate from the residue was above 85.21% at the conditions of NaOH concentration 12g/L， Na2CO3 concentration 210g/L， leaching temperature 95℃， leaching time 120min and liquidsolid ratio 6. The whiteness of the aluminum hydroxide obtained was over 98. The chemical formulation of the product is αAl(OH)3. The SEM results showed that the grain size was less than 1μm. References | Related Articles | Metrics

Mechanical Engineering

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Vibration Characteristics Analysis of Helical Gear Rotor Systems Using the Integral Model WANG Qibin， HU Peng， ZHANG Yimin， MA Hui 2014, 35 (5):  721-725.  DOI: 10.12068/j.issn.1005-3026.2014.05.026 Abstract ( 532 )   HTML   PDF (1651KB) ( 692 )   Taking the tooth stiffness distribution， transmission error distribution， translational stiffness， twist stiffness and the center of stiffness into account， a dynamic model for general helical gear pairs is developed. Then the rotors and bearing flexibility are introduced to the model， and a finite element model for the rotor system of helical gear is determined. Finally， dynamic responses are analyzed based on the gear rotor systems. The results show that the model is effective and accurate for general helical gear rotor systems. Moreover， through studying the fast Fourier transform of the dynamic mesh force， the 1×mesh frequencies of the system has a main influence on the response the rotor system. References | Related Articles | Metrics

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Dynamic Characteristics of StatorRotor Interaction in Multidisks Dualrotor System LI Chaofeng， ZHOU Shihua， YANG Shuhua， LIU Guangchao 2014, 35 (5):  726-730.  DOI: 10.12068/j.issn.1005-3026.2014.05.027 Abstract ( 503 )   HTML   PDF (3136KB) ( 648 )   A finite element model of dualrotor system and the rotor/stator contact model were established to investigate the effects of rubimpact. To make the results more accurate， the influences of shear， inertia distribution， lateral torsional and geometric parameters of the system were considered in the model. The dynamic response of dualrotor system to the varied contact gaps was studied. Results indicate that period3 is present in most parts of the rotor due to the inherent property of the dualrotor system. Aperiodic motion is present in the whole system because of the effect of rubbing contact. Specifically， the aperiodic motion presented in the rotor without rubbing contact (inner rotor) is not obvious due to the intershaft bearing. It is shown that the intershaft bearing can not only couple the inner/outer rotor but isolate the vibration. References | Related Articles | Metrics

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Effect of Friction Coefficients on the Backup Rolls’ Subsurface Contact Fatigue Damage SUN Dale， QIN Xiaofeng， XIE Liyang， WU Qiong 2014, 35 (5):  731-734.  DOI: 10.12068/j.issn.1005-3026.2014.05.028 Abstract ( 683 )   HTML   PDF (509KB) ( 1208 )   The orthogonal shear stress was selected as the key stress controlling the subsurface rolling contact fatigue damage. The influence of friction coefficient on the subsurface orthogonal shear stress under rolling contact was analyzed. Based on the linear fatigue accumulation rule and a modified equation for the stress rang of unsymmetrical cycling stress， the relationship between the subsurface stress and fatigue life was established to assess the subsurface rolling contact fatigue damage of backup rolls. An instance was implemented to analyze the influence of friction coefficient on the subsurface rolling contact fatigue damage of backup rolls. The result shows that the subsurface rolling contact fatigue damage of backup rolls increase with the increase of stress ratio and friction coefficient. So the fatigue damage of backup roll can be lessened by decreasing its friction coefficient. References | Related Articles | Metrics

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Modeling and Research of the Intermesh for Continuously Straightening a ThinWalled Tube in Uniaxial Stress ZHANG Ziqian， YAN Yunhui， YANG Yuilin， ZHAO Xinjun 2014, 35 (5):  735-738.  DOI: 10.12068/j.issn.1005-3026.2014.05.029 Abstract ( 535 )   HTML   PDF (729KB) ( 609 )   The straightening intermesh as the main straightening technical parameter， which decides the precision for straightening thinwalled tubes， is usually carried out based on the experiential data and chart by experience and experiments. Firstly a new simplified mechanical model for calculating the intermesh is presented， and the bendingmoment of the cross section is subsequently obtained in the elastic zone and also in the elasticplastic zone. Then the model of the straightening intermesh is presented by the integration of the bendingmoment equation. In order to certify the correctness， some dynamic simulations were done by LSDYNA， and the results indicate that the model is correct. An intermesh curve is plotted using the datum calculated with the model， by which the influence of the parameters can be analyzed qualitatively， thus the theoretical basis for adjusting the intermesh for the production can be provided. References | Related Articles | Metrics

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Module Division System of CNC Machine Tools Based on Hierarchical Clustering WANG Pengjia， GONG Yadong， LIU Yongxian， ZHANG Chaobiao 2014, 35 (5):  739-742.  DOI: 10.12068/j.issn.1005-3026.2014.05.030 Abstract ( 660 )   HTML   PDF (528KB) ( 584 )   Combining with practice of module division of CNC horizontal lathe， the correlation degree matrix was gotten by computing the correlation degree of subfunctions. The hierarchical clustering method was used to aggregate the distance matrix and the module division scheme was obtained. On that basis， the module division system was developed using the VB and Matlab softwares. The example design and analysis results show that the division system is effective， rapid and accurate in the module division process. References | Related Articles | Metrics

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Surface Roughness and Surface Topography of MicroGrinding SodaLime Glass WEN Xuelong， WANG Chao， GONG Yadong， CHENG Jun 2014, 35 (5):  743-746.  DOI: 10.12068/j.issn.1005-3026.2014.05.031 Abstract ( 668 )   HTML   PDF (622KB) ( 702 )   A series research of microgrinding with sodalime glass was conducted， and discussed the influence of different grinding factors on the surface roughness and 3D surface topography. According to the characteristics of microgrinding， the three factors and five levels orthogonal experiments were conducted by sodalime glass. The 200# and 500# grits microgrinding tools were separated under different processing conditions. The main factors influencing the machining quality were the surface roughness and surface topography. The results show that the main factors influencing the surface roughness and 3D surface topography are spindle speed and approach speed. The grinding depth is not the major impact. It provides the reference for the surface quality of microgrinding and intense research of microgrinding. References | Related Articles | Metrics

Resources & Civil Engineering

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Research of Quaternary Megaloceros Fossils in North ErshiJiazi Town， Liaoning Province ZHANG Zhibin， GONG Enpu， ZHAO Mingpeng， WANG Haijiao 2014, 35 (5):  747-750.  DOI: 10.12068/j.issn.1005-3026.2014.05.032 Abstract ( 739 )   HTML   PDF (864KB) ( 724 )   Based on a preliminary analysis of the Quaternary mammalian fossils unearthed near North ErshiJiazi Town in Jianping County， of Liaoning Province， it was found that these fossiles are the antlers of megaloceros， developed from the warm humid steppe ecosystem during the Cenozoic midPleistocene. By a contrast study of regional stratigraphy and other fossils， these fossils with strong siliconization were formed in the early Pleistocene. The antler fossils were buried in the loess soil， a product of the dry and cold weather conditions， so the studied area had been warm and humid， and became dry and cold hereafter. It might be concluded that the mammals were affected more by climate changes and finally died out. References | Related Articles | Metrics

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PCRDGGE Analysis of Microbial Community Structure in a Electrocoagulation Membrane Bioreactor LI Liang， HU Xiaomin， YU Danjing， CHEN Wenxi 2014, 35 (5):  751-755.  DOI: 10.12068/j.issn.1005-3026.2014.05.033 Abstract ( 649 )   HTML   PDF (597KB) ( 718 )   A new submerged electrocoagulation membrane bioreactor (ECMBR) was developed by installing ferric plates on both sides of membrane module in the traditional submerged membrane bioreactor (SMBR) to treat the simulated dying and printing wastewater with active brilliant blue XBR. The removal efficiency of ECMBR on COD， NH+4—N， TN， TP and chroma was respectively 2.7%， 3.8%， 4.7%， 39.2% and 28.6% higher than that of SMBR. The PCRDGGE analysis was used to explore the evolution of bacterial community in ECMBR and SMBR. The diversity Shannon index of the whole bacterial community in ECMBR was 2.9， higher than that in SMBR. Moreover， the bacterial community structure underwent small changes， with a 97% similarity in both ECMBR and SMB. The results showed that it was possible to enhance the bacterial community diversity by electrocoagulation. References | Related Articles | Metrics

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Effects of Natural Fractures on Hydraulic Fractures Propagation of Coal Seams SONG Chenpeng， LU Yiyu， XIA Binwei， HU Ke 2014, 35 (5):  756-760.  DOI: 10.12068/j.issn.1005-3026.2014.05.034 Abstract ( 847 )   HTML   PDF (642KB) ( 840 )   To investigate the effects of natural fractures on the hydraulic fracture propagation of underground coal seams， a twodimensional model of hydraulic fracture intersecting natural fractures was built， based on which， the laws of fracture propagation and the failure mechanisms of natural fractures were explored by applying theoretical analysis and numerical simulation. The research suggested that the angle of interaction， the horizontal differential principal stress and the development degree of natural fractures are the three main factors that affect the directions of fracture propagation. In the case of low horizontal differential principal stress and low angle of interaction， the propagation of hydraulic fractures is likely along the natural fractures due to shear failure; on the contrary， in the case of high horizontal differential principal stress and high angle of interaction， the propagating fracture is likely to cross the natural fractures. Smallsized natural fractures have little or no effect on the directions of hydraulic fracture propagation whereas the propagating fractures move along the natural fractures when they are bigger in size. References | Related Articles | Metrics