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Parametric Adaptive Control for Affine Nonlinear Singular Systems YANG Dong-mei， WANG Xiao-fang 2013, 34 (1):  1-4.  DOI: - Abstract ( 545 )   HTML   PDF (277KB) ( 759 )   The parametric adaptive control problem was studied for a class of affine nonlinear singular systems with unknown parameter.Firstly， the affine nonlinear singular systems were transformed into generally linear singular systems via diffeomorphic transformation using Lie derivative and Lie bracket.Then， combined with LMI method and the Lyapunov stability theory， the parametric adaptive control method was used to construct an adaptive regulator.What’s more， a sufficient condition was given under which the system was asymptotically stable at the point of equilibrium and parameter error was asymptotically convergent.Lastly， a simulation was constructed using Matlab， and the results of simulation showed the effectiveness and feasibility of the presented method. References | Related Articles | Metrics

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Long Term Object Tracking Algorithm Based on Random Ferns TONG Guo-feng， JIANG Zhao-yan， GU Jiu-hong， PANG Xiao-lei 2013, 34 (1):  4-8.  DOI: - Abstract ( 656 )   HTML   PDF (701KB) ( 1327 )   In order to realize the object tracking in complex situation such as occlusions， partial and full changing illuminations， appearance change or fast motion， a novel object tracking framework was proposed by adopting the method that combined standard object tracking with object detection. The tracking algorithm based on the error of the evaluation standard two-way consistency was put forward to improve the reliability of the tracking point. The target detection algorithm based on random fern plexus was able to initialize objective to again track object， when the object was sheltered and disappear， failure to track. The proposed object tracking algorithm was proved to be able to achieve the goal of long-term tracking and be very robust. References | Related Articles | Metrics

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A High Accurate and Real Time Filter Method for Pressure Signal of Fluid Pipeline LIU Jin-hai， FENG Jian， MA Da-zhong 2013, 34 (1):  9-12.  DOI: - Abstract ( 809 )   HTML   PDF (314KB) ( 814 )   A sampling frequency was designed according to the analysis of pressure signal for the purpose of leak detection of fluid pipeline.A united filter method including low-pass filter， notch filter and wavelet filter was proposed， and then the detailed implementary steps and parameters of the united filters were given.The united filters could filter the noise in pressure signal and recover the amplitude and phase of abnormal pressure which could improve the accuracy of leak detection effectively.At last， two cases were used to verify the united filters， and the results showed that the proposed filter method is effective. References | Related Articles | Metrics

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Brushless DC Motor Servo Control Based on Compensation Fuzzy Neural Network GU De-ying， WU Cheng-sai， HOU Jiao 2013, 34 (1):  13-16.  DOI: - Abstract ( 720 )   HTML   PDF (344KB) ( 815 )   In order to implement high precision position tracking controlling for the brushless DC motor(BLDCM)， a CFNNC (compensation fuzzy neural network controller) algorithm was proposed based on the multivariable， nonlinearity， strong coupling， time-variable characteristics of position servo system. The compensative fuzzy logic and neural network were combined in the proposed algorithm， which could not only adjust the input and output of fuzzy membership functions， but also optimize the fuzzy inference dynamically by using the logic compensation algorithm. The fault tolerance， stability and working speed of the network were improved greatly due to the introduction of fuzzy neuron. The simulation and experiment results of DSP-based control system illustrated that this method has rapid response， high precision and robustness， and its dynamic characteristic was much better than that of traditional PID controller. References | Related Articles | Metrics

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Multi-objective Optimization Model of Line-Cell Conversion Towards Reducing Workers YU Yang， TANG Jia-fu， GONG Jun 2013, 34 (1):  17-20.  DOI: - Abstract ( 700 )   HTML   PDF (228KB) ( 690 )   To improve the production efficiency， considering the multi-batch and small-volume demand of the electronics manufacturing industry， more and more companies adopted the cell production conversed from the traditional assembly convey line. It was researched to reduce the workers by the line-cell conversion with the constraint of not increasing the total throughput time. According to the feature of the line-cell conversion towards reducing workers， a multi-objective model was set up. The line-cell conversion was an NP-hard problem， and so an algorithm based on NSGA-II was proposed to solve it. Several numerical simulation experiments were performed to illustrate that the line-cell conversion can be used to reduce workers without increasing the total throughput time at the same time. References | Related Articles | Metrics

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Location Privacy Protection for Wireless Sensor Networks Based on Fan-Shaped Region LI Feng-yun ， LI Pei-yu， GAO Fu-xiang， CHANG Gui-ran 2013, 34 (1):  21-25.  DOI: - Abstract ( 662 )   HTML   PDF (440KB) ( 555 )   The traditional location privacy protection algorithms in wireless sensor networks can not get a well balance between the security and network energy consumption. To resolve this problem， a routing algorithm of random relay node was proposed on the basis of the fan-shaped region. The range of routing path was controlled by adjusting the size of the fan-shaped region. In order to protect the location privacy of the source node， a mechanism was adopted which could randomly select a fan-shaped sub-region as the optional area of the next hop. Simulation results showed that comparing with Phantom routing and other routing algorithms， the proposed algorithm can effectively protect the location privacy of the source node without affecting the data transmission ratio， and has lower energy consumption. At the same time， the algorithm has better flexibility， and the high security or low energy cost mode can be set according to the practical demand. References | Related Articles | Metrics

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Stability Analysis of ASBS Adaptation Behavior GE Liang， ZHANG Bin， ZHANG Chang-sheng， ZHAO Xiu-tao 2013, 34 (1):  25-29.  DOI: - Abstract ( 553 )   HTML   PDF (340KB) ( 718 )   The stability analysis of adaptive behavior in adaptive strategy construction of adaptive service based software system was investigated. Reflective Petri net based analysis method was adopted， where business behavior and adaptive behavior were modeled in different levels separately and the business behavior model was unaware of the adaptive behavior model. The definition of adaptive behavior stability was proposed based on system’s reflective Petri net model. The modeling method of adaptive rules which consists the adaptive strategy was provided and stability verification method of adaptive behavior based on reflective Petri net was presented as well. Finally， an example was used to illustrate the feasibility and effectiveness of the proposed approach. References | Related Articles | Metrics

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Fuzzy Query Approach for XML Based on Algebraic Operations YAN Wei， MA Zong-min 2013, 34 (1):  30-34.  DOI: - Abstract ( 509 )   HTML   PDF (400KB) ( 802 )   Users often have fuzzy or imprecise requests when querying XML documents.Based on algebraic operations， a novel approach was proposed to express user’s fuzzy query intention.A set of fuzzy algebraic operations was defined， which could support fuzzy query in XML.The user’s fuzzy query condition was respected by the fuzzy query results perfectly.To deal with the problem of too many query results， a ranking approach was proposed， which considered the relevance between the membership degree and user-defined weights.The top-k answers of the fuzzy query results were computed efficiently.The efficiency of the method was demonstrated by the results of a preliminary user study.The user’s fuzzy query intention could be captured by fuzzy algebraic operations effectively. References | Related Articles | Metrics

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Optimal Trunk Node Selection Based on Group-Based Acknowledgement Mechanism in Vehicular Networks ZHAO Hai， PENG Hai-xia， ZHU Jian， LI Da-zhou 2013, 34 (1):  35-39.  DOI: - Abstract ( 508 )   HTML   PDF (363KB) ( 893 )   According to the location-specific vehicular subscriber node and sink node， the end-to-end throughput of the vehicular networks was improved by selecting out the optimal trunk node. Incorporating this issue into the vehicular networks model which is based on the group-based acknowledgement mechanism， and combining with data retransmission technology and multi-hop relay technology， the optimal trunk node selection (OTNS) algorithm was presented. With the help of the nonlinear optimization method， the location of the optimal trunk node between the vehicular subscriber node and sink node was ultimately determined， which made the end-to-end throughput between the vehicular subscriber node and sink node reach its maximum. Finally， the effectiveness of this algorithm was verified through the simulation experiments， which showed that the selection of optimal trunk node is useful for increasing the vehicular networks performance. Compared to not using the optimal node， the vehicular networks end-to-end throughput expectation was improved on the basis of the proposed method. References | Related Articles | Metrics

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Evolution Analysis of Standard Structure Entropy and Degree of Software Macro-topology XU Jiu-qiang， LU Suo， LIU Zheng， ZHAO Hai 2013, 34 (1):  40-44.  DOI: - Abstract ( 561 )   HTML   PDF (528KB) ( 829 )   Modern software life circle can be considered as a software architecture evolutionary process. Based on the statistical data calculated from a large number of open-source software systems， the changing of standard structure entropy， the number of high degree nodes and the ratio of new added low degree nodes were analyzed respectively. And the changes in the number of nodes with high degree centrality indicator in overall network and new added nodes were subsequently analyzed. Analysis results revealed a universal phenomenon that， the number of nodes with high standard structure entropy and high degree centrality indicator was declining， while the number of high degree nodes was increasing. Most of new added nodes were lower-degree. It could be concluded that the growth of complexity in software networks and software architecture was gradually slowing down within the process of a successful software evolution. It is significant to the guide the software development. References | Related Articles | Metrics

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A Peer-to-Peer Overlay Network Routing Algorithm Based on Multiple Circle Topology MA Yi， CHEN Dong-ming， CHANG Gui-ran， TAN Zhen-hua 2013, 34 (1):  44-47.  DOI: - Abstract ( 543 )   HTML   PDF (289KB) ( 759 )   The routing algorithm of randomly selecting neighbor nodes is mostly used in P2P applications， which decreases the routing efficiency and increases the routing hops. To solve this problem， a new routing algorithm named RMCT based on multiple circle topology was presented. Nodes were dynamically divided into a number of clusters which used sub-supernodes to manage. A short routing table based on constant grade was defined. In RMCT， maintaining the route table for nodes entering/exiting were presented， as well as the clusters building method and distributed election algorithm for sub-supernodes. Compared to the performance of such typical algorithms as Chord， the RMCT algorithm greatly improved the performance in regard to routing table maintaining， routing hops， and network delay. Simulations and analysis results showed that the RMCT was an efficient routing algorithm though some problems were to be studied further. References | Related Articles | Metrics

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Metal Artifacts Reduction in CT Images via Redundant Representation MAO Bao-lin， CHEN Yong-li， XIAO Da-yu， KANG Yan 2013, 34 (1):  48-51.  DOI: - Abstract ( 915 )   HTML   PDF (414KB) ( 858 )   A new calibration method based on redundant representation was proposed for metal artifacts in CT medical images. First of all， metal projection region was obtained by projecting the segmented metal region. Then， the data of metal projection region was subtracted from the original projection data. Finally， the metal projection data was restored by using redundant representation method and the corrected image was generated after filtered back projection. The calibration results showed that the proposed method can reduce metal artifacts effectively in the reconstructed images. References | Related Articles | Metrics

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Effective Automated Kidney Locating and Segmentation Method Based on Multi-phase MR Images LI Hong， PAN Xiao-guang， SUN Hao-ran， KANG Yan 2013, 34 (1):  52-56.  DOI: - Abstract ( 563 )   HTML   PDF (734KB) ( 736 )   Automatically locating the kidney region and segmenting the kidneys in MR images are the first and very important steps for the whole renal function analysis flow. A novel method of automatically locating the kidney based on multi-phase MR images was proposed. First， 3D registration and subtraction were employed; then max intensity projection along different directions was performed to get projection images; afterwards， the MID(maximum intensity distribution) curve analysis was used to obtain the kidney region boundary. Inside the kidney region， the level set method was employed to segment each kidney on the parenchymal phase images. Finally， the segmentation result was mapped onto all the other phase images. Experimental results showed that the location results are very good， and the segmentation performed within the location region has higher efficiency and better accuracy. References | Related Articles | Metrics

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Effects of High Magnetic Fields on Solidified Microstructure and Solute Element Distribution in Al-Cu Alloy YUAN Yi， WANG Qiang， LIU Tie， HE Ji-cheng 2013, 34 (1):  57-61.  DOI: - Abstract ( 716 )   HTML   PDF (847KB) ( 938 )   The solidification of Al-10.5wt%Cu hypoeutectic alloy was carried out in uniform and gradient high magnetic fields. The influences of high magnetic fields on the morphology of microstructure and solute elements content inside α-Al grains were investigated. The results revealed that the solute element content inside grains is increased by uniform high magnetic fields while the morphology of microstructure keeps almost unchanged. And， these phenomena are analyzed from the viewpoint of the Lorentz force which suppresses the migration of Cu atoms towards the liquid phase at the solid/liquid interface and consequently increases the solute element content inside α-Al grains. For gradient high magnetic fields， the solute content inside α-Al grains changes insignificantly when the direction of gradient high magnetic fields is changed. References | Related Articles | Metrics

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Microstructure Evolution and Mechanical Properties of a Novel Medium-Mn Hot-Rolled TRIP Steel CAI Zhi-hui， DING Hua， XUE Xin 2013, 34 (1):  62-66.  DOI: - Abstract ( 706 )   HTML   PDF (1409KB) ( 931 )   A new heat treatment was applied to a novel medium manganese transformation induced plasticity (TRIP) steel designed with the Thermo-Calc software. The proportion and stability of retained austenite were studied， and the microstructure and mechanical properties of the experimental steel were analyzed. The results showed that the tensile strength of tested steel is nearly 1000MPa， the elongation is over 30%， and the product of ultimate tensile strength and total elongation exceeds 30GPa·%. The mechanical properties are significantly influenced by the solution temperature. When the hot-rolled steels are treated at the solution temperature range of 750~800℃， the best properties are obtained. References | Related Articles | Metrics

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Effects of Nb and Final Quenching on Microstructure and Mechanical Property of Q＆P Steels ZHANG Jun， DING Hua， TANG Zheng-you， LI Mao 2013, 34 (1):  66-70.  DOI: - Abstract ( 793 )   HTML   PDF (1350KB) ( 715 )   Two kinds of steels 0.19C-1.52Si-1.53Mn-0.14Al-0.048Nb and 0.19C-1.52Si-1.48Mn-0.15Al were treated by Q＆ P (quenching and partitioning) process. The effect of final quenching on the microstructure and mechanical property of Q＆ P steels was studied. The results showed that the addition of Nb has the effect of fine grain strengthening and precipitation strengthening. The combination of elongation and tensile strength achieves 25190MPa·%. And the final quenching process increases the volume of martensite and greatly improves the tensile strength and yield strength of Q＆ P steels. Meanwhile， this process decreases the total elongation and work hardening index of the steels. The steels without final quenching process have the better mechanical properties with high total elongation but the relatively low strength. References | Related Articles | Metrics

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Oxidation Kinetics and Oxide Scales Control of Hot-Rolled High Strength Steel CAO Guang-ming， SUN Bin， LIU Xiao-jiang， ZHANG Lin 2013, 34 (1):  71-75.  DOI: - Abstract ( 600 )   HTML   PDF (718KB) ( 1360 )   The oxidation kinetics and transformation behaviors of FeO formed on high-strength steel (610L) were studied by oxide weight gain experiment and thermal simulation at different oxidation temperature and different isothermal holding time. Oxidation kinetic model under the condition of alternative temperature was derived， and the evolution rule of oxide scales of high-strength steel during hot strip rolling was studied. The isothermal transformation curves for 610L were measured. The results showed that the isothermal transformation of FeO includes two kinds of phase transformations， the first one is the proeutectoid precipitation of Fe3O4， and the second is the eutectoid transformation of FeO→Fe+Fe3O4. The range of the pro-eutectoid reaction “nose” temperature of 610L is 350~500℃， and the eutectoid reaction “nose” temperature is 350~450℃. These results are useful for the oxide scale structure control. References | Related Articles | Metrics

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Research on Variation of Work Piece Horizontal Velocity for Variable Gauge Rolling ZHANG Guang-ji， LIU Xiang-hua， HU Xian-lei， ZHI Ying 2013, 34 (1):  75-79.  DOI: - Abstract ( 607 )   HTML   PDF (517KB) ( 1089 )   To reveal the relationship between the work piece horizontal velocity and roll vertical velocity during variable gauge rolling (VGR)， the differential equation of work piece horizontal velocity (equation VGR-V) was set up by keeping material volume. Then it was solved under the VGR boundary conditions， and the formula to calculate the work piece horizontal velocity was obtained. Furthermore， it was proved that equal discharge per second condition (EDSC) no longer fits VGR processes. Some typical examples were given， so that the influence of technological parameters on the work piece horizontal velocity was presented. It provided a theoretical basis for researching on deformation parameters and mechanical parameters in VGR processes. References | Related Articles | Metrics

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Microstructure and Mechanical Properties of Wire and Welded Joints Using Domestic and Imported 5183 Welding Wire WANG Dong， HE Chang-shu， WANG Hao， ZHAO Xiang 2013, 34 (1):  80-84.  DOI: - Abstract ( 642 )   HTML   PDF (1316KB) ( 721 )   5083-O alloy plates were welded by metal inert gas (MIG) welding method using domestic and imported 5183 welding wire. The microstructures and mechanical properties of wire and welded joints were studied by optical microscopy， tensile test methods and SEM. The results showed that the domestic 5183 wire has higher yield strength and slightly lower elongation than that of the imported 5183 wire. Weld beads are fairly good under the chosen welding parameters. The microstructures of welded joints using domestic and imported 5183 welding wire are similar. The weld zone is the typical casting structure formed during weld solidification. Grains are elongated along the rolling direction and parts of precipitated phases dissolve in the matrix in the heat-affected zone. The tensile strength of the joints welded with either domestic or imported 5183 welding wire can reach more than 85% of the base material. References | Related Articles | Metrics

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FEM Analysis of Anti-deformation Capability for Coal Mine Refuge Chamber Suffered to Gas Explosion MEI Rui-bin ， LI Chang-sheng， CAI Ban， LIU Xiang-hua 2013, 34 (1):  85-90.  DOI: - Abstract ( 692 )   HTML   PDF (1425KB) ( 715 )   It is difficult to carry out the experiments of explosion and safety for refuge chambers because of the danger and nonrepeatability of the explosion. The structure deformation and distribution of equivalent stress were investigated under different explosion pressure conditions based on the FEM and software LS-DYNA. The results showed that the distribution of deformation and equivalent stress has the same trend on the same surface with the increment of explosion pressure. The deformation and stress on the sides are more serous and larger compared with that of front of the chamber with the same explosion pressure. The stiffener and outer steel are easy to become invalidation because of the maximum equivalent stress. Furthermore， the deformation of the whole chamber is elasticity with impact pressure 1.5MPa. When the impact pressure is 2.0MPa， the deformation of the front still belongs to elasticity but the less plasticity occurs on the stiffener. However， it is safety for the chamber structure because the equivalent stress 283MPa is much less than the tensile strength. References | Related Articles | Metrics

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Experimental Study on Distribution of Pulverized Coal in the Packed Bed with Bi-PCI Process DING Zhi-min， WEI Guo， GAO Qiang-jian， SHEN Feng-man 2013, 34 (1):  90-94.  DOI: - Abstract ( 490 )   HTML   PDF (491KB) ( 1022 )   A two-dimensional packed bed model was established with 1∶25 scale for simulating the PCI (pulverized coal injection)process and the Bi-PCI (bisegment pulverized coal injection)process based on similarity theory. The distributions of powder and pressure were investigated when PCI and Bi-PCI were used respectively. The results showed that the pulverized coal mainly accumulates in the lower part of packed bed， and the accumulation of pulverized coal decreases with increasing height of packed bed. The pulverized coal from the second lance accumulates in the edge region of the packed bed， and the holdup of the mid region is from the tuyere. At the same conditions， the distribution of pulverized coal becomes more uniform at height direction， and the permeability of packed bed is improved when Bi-PCI is adopted. So the pressure drop in packed bed is reduced by 29% compared with the PCI， mainly because the pressure drop significantly decreases in lower part of packed bed. The pulverized coal that have been injected by the secondary lance has little influence on the pressure drop in the upper of the packed bed. References | Related Articles | Metrics

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Miscibility and Thermostability of Epoxy Acrylate-POSS Nanocomposites WANG Ying， YANG He， LIU Feng-guo， XUE Xiang-xin 2013, 34 (1):  95-98.  DOI: - Abstract ( 613 )   HTML   PDF (744KB) ( 587 )   Methyl-polyhedral oligomeric silsesquioxanes (POSS) were blended with epoxy acrylate (EA) to prepare nanocomposites through UV-curing process. The methyl-POSS nanoparticles were added to EA by physically blending at loadings of 1wt%， 5wt%， 10wt% and 15wt%. The EA/POSS nanocomposites were studied through XRD， SEM， EDS and TGA analysis. The results showed that there are methyl-POSS crystals in samples containing high POSS mass fraction，implying the existing of phase separation in EA/POSS nanocomposites. The POSS aggregates are observed in the nanocomposites， and both the size and number of aggregates are all increased with the increasing of POSS loadings. There are also POSS molecules dispersing in the EA matrix. The nanocomposites thermal stability is improved and the degradation mechanism of EA is not affected by POSS. References | Related Articles | Metrics

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Transmission Behavior of Subwavelength Periodical Metallic Slit Structure WANG Ai-hua， CAI Jiu-ju 2013, 34 (1):  98-102.  DOI: - Abstract ( 558 )   HTML   PDF (641KB) ( 747 )   Mid-infrared transmittance of subwavelength silver slit structures was numerically studied with the finite difference time domain method. The TM (transverse magnetic) wave transmission behavior at normal incidence was also further investigated by looking into electromagnetic fields and Poynting vectors of selected slit geometries. The results showed that for the slit structures without square features attachment， the transmittance increases monotonically with the wavelength， but is not proportional to the slit width. Given the slit structures with square features at the inlet， the effect of square features attachment mode and side length on the transmittance are different for the various slit widths. Based on the analysis of electromagnetic field and Poynting vectors， such transmittance change can be attributed to the cavity resonance effect inside the slit arrays. References | Related Articles | Metrics

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Effect of MgO on Compressive Strength of Pellet GAO Qiang-jian， WEI Guo， HE Yi-bo， SHEN Feng-man 2013, 34 (1):  103-106.  DOI: - Abstract ( 691 )   HTML   PDF (542KB) ( 1457 )   The caustic calcined magnesite was used as an additive to produce an oxidized pellet. The effect of MgO-bearing on the compressive strength of pellet was investigated. The results showed that with the addition of MgO-bearing in pellet， the compressive strength of pellet decreases gradually. The reasons as follows:(1)the MgO makes against the recrystallization of Fe2O3 after Fe3O4 is oxidized to Fe2O3. The recrystallization of Fe2O3 is fainter， the crystallite is maldistributed and the consolidation of pellet is incomplete; (2)according to the pore space analysis of different MgO-bearing in pellets， with the addition of MgO-bearing in pellet， the porosity and aperture increase， leading to the decreasing of compressive strength of pellet. References | Related Articles | Metrics

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Experimental Study of Chemical Looping Air Separation Technology Using Cu-Based Oxygen Carrier WANG Kun， YU Qing-bo， QIN Qin， LI Jiu-chong 2013, 34 (1):  107-110.  DOI: - Abstract ( 676 )   HTML   PDF (528KB) ( 817 )   The optimal reaction temperatures were investigated via the temperature programmed thermogravimetry， and the effects of particle size， species of binder， mixing ratio and reaction temperature on reduction reaction were studied via the isothermal thermogravimetry using STA409PC thermal analyzer. The results showed that the Cu-based oxygen carrier has the high reactivity of releasing oxygen when the temperatures are from 850℃ to 1000℃. The reaction rates have the tendency of increasing as particle sizes decrease and content ratios of binder increase， but the tendency is not apparent. The binders of SiO2， ZrO2 and TiO2 combined with CuO show high reactivity and conversion ratio. The reaction rates increase greatly as the temperature increases. References | Related Articles | Metrics

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Study on the Reaction Kinetics of Forsterite Synthesis CHEN Yong， YUAN Lei， LIU Tao， YU Jing-kun 2013, 34 (1):  111-114.  DOI: - Abstract ( 719 )   HTML   PDF (542KB) ( 899 )   The reaction kinetics of forsterite synthesis was studied through solid-phase reaction by using analytically pure magnesium oxide， high purity fused silica and fused magnesia particles as main raw materials. The effects of the sintering temperature and holding time on the synthesis of forsterite were studied by X-ray diffraction analysis and scanning electron microscopy. The mechanism of reaction between MgO and SiO2 was discussed. The reaction kinetics equations of the reaction process between MgO and SiO2 in the range of 1100~1300℃ were established， and the apparent reaction activation energy was obtained according to the experimental results. The results showed that forsterite synthesis rate gradually increases with the synthesis temperature and holding time increasing. Forsterite and enstatite are formed during the initial stage of synthesis reaction， and the reaction process of MgO and SiO2 is controlled by the Mg2+ diffusion. The apparent reaction activation energy is (220±20)kJ/mol. References | Related Articles | Metrics

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Pivot Steering Control and D2P Real-Time Simulation for Electric Tracked Vehicle CHEN Ze-yu， ZHAO Guang-yao， ZHAI Li， TONG Shang-e 2013, 34 (1):  114-117.  DOI: - Abstract ( 639 )   HTML   PDF (453KB) ( 1254 )   In order to improve the pivot steering performence of electric tracked vehicle， a control strategy using dual electric motor torque control was proposed on the basis of pivot steering kinetic model. First， motors’ maximum torque was set as the initial value so as to improve the dynamics response speed. Then， driver steering wheel angular signal was introduced into yaw velocity negative feedback gain for the driver to control the steering speed. Driver and controller in the loop simulation platform for tracked vehicle pivot steering was built on the basis of D2P prototype development system. The real-time simulation results show that the control strategy is correct， effective and real-time. References | Related Articles | Metrics

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Modeling and Simulation of Regenerative Chatter Stability in CNC Lathing Process LI Jin-hua， XIE Hua-long， SHENG Zhong-qi， LIU Yong-xian 2013, 34 (1):  118-122.  DOI: - Abstract ( 698 )   HTML   PDF (583KB) ( 1227 )   Taken into account of the variation of the transient chip and cutting angle， a dynamic model was proposed for the ex-circle computerized numerical control (CNC) lathing based on the regenerative chatter theory. By applying digital simulation technique， a software package was developed to do simulations for available experimental data. The simulation results clearly showed the nonlinear relation between the limited cutting width and the spindle speed， and the spindle speed has more effect on the chatter than other factors. The stability increases with increase of the equivalent stiffness or the damping ratio in vibrating system， but it will decline when the directional coefficient， cutting overlapping coefficient or cutting stiffness increases. And the shapes of the lobes are simultaneously changed. However， the natural frequency of the vibrating system has no effect on the shapes of the stability lobes， and the lobes integrally move to the right with its increase. These results provide theoretical basis for chatter suppression. References | Related Articles | Metrics

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An Explosives Identification Method Based on the Bayesian Decision Theory SUN Li-na， YANG Bin 2013, 34 (1):  123-126.  DOI: - Abstract ( 514 )   HTML   PDF (290KB) ( 793 )   For explosives recognition problem in safety inspection field， dual-energy X-ray transmission technology， low-energy forward scattering and back scattering technology were combined to get the gray-levels of dual-energy transmission， low-energy forward scattering and back scattering images taking the feature extraction and recognition of the radiation data as the core. The eigenvalue R associated with effective atomic number and the eigenvalue L associated with density were obtained. Based on the least mistake probability， the eigenvalue R and L were synthesized to get the discriminate， decision-making plane and distinguish rule. The experiments validated that the correct rate of the discrimination rules by the Bayesian decision theory is up to 90%， and it is a more effective method for solid explosives identification that improves the detection capability of X-ray comprehensively. This may significantly contribute to recognition of solid explosives. References | Related Articles | Metrics

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Strength Reduction Method for Rock Slope Stability Analysis Based on PFC2D WANG Pei-tao， YANG Tian-hong， ZHU Li-kai， LIU Hong-lei 2013, 34 (1):  127-130.  DOI: - Abstract ( 720 )   HTML   PDF (1320KB) ( 1119 )   Strength reduction method was implemented into the particle flow code (PFC2D) that is based on discrete element method (DEM)， to tackle the difficulties for the slope stability analysis based on continuum mechanics. In this regard， the ratio of average unbalanced mechanical force as the failure criteria to judge the unstable failure of slope， the cohesive force and frictional coefficient were reduced to capture the coalescence of fractures， this approach could not only qualitatively judge the local failure of the slope， but also monitor the complete instable failure process of the slope. By means of strength reduction method， safety factor could be finally calculated automatically. The proposed method was applied to the rock slope stability analysis of Heishan metal mine. Slope safety factors under different conditions were obtained respectively. The safety factors of 1.803 and 1.183 before and after the excavation of slope were obtained respectively， which agree with the expectations. References | Related Articles | Metrics

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Experimental Study on Catalytic Removal of NO○xand SO2 from Simulation Gas by SNOX Method HAO Wen-ge， HAN Jing， CHEN Xi 2013, 34 (1):  131-135.  DOI: - Abstract ( 544 )   HTML   PDF (448KB) ( 777 )   The influences of practical technological conditions of SNOX method on the catalytic removal efficiencies of NO○x and SO2 from flue gas were studied experimentally. For studying the catalytic reduction reaction of NO○x， CuO/γ-Al2O3catalyst was prepared by impregnation method. The influences of reaction temperature， space velocity， n(NH3)/n(NO○x) and SO2 concentration on the conversion rate of NO○x were investigated. For studying the catalytic oxidation reaction of SO2， V2O5 catalyst was applied. The influences of reaction temperature， space velocity， n(O2)/n(SO2) on the conversion rate of SO2 were investigated. Based on the experimental results， kinetic calculations for the reactions were carried out. The results showed that， under the optimum conditions， the reduction rate of NO○x can reach 87.5%， and after two stages of oxidation， the conversion rate of SO2 can reach 94.3%. References | Related Articles | Metrics

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Application of Isolation Piles on Metro Tunnel for Side-Crossing the Buildings with Shallow Foundation JI Xin-bo， ZHAO Wen， LI Shen-gang， ZHOU Zuo-shun 2013, 34 (1):  135-139.  DOI: - Abstract ( 522 )   HTML   PDF (510KB) ( 863 )   The mechanical behavior and deformation of a metro tunnel using isolation piles adjacent to existing buildings with shallow foundation were studied with orthogonal finite element analysis method. Comparative analysis was implemented to examine:the settlement at the surface of existing building， the isolating effect of isolation piles and effectiveness of grouting on tunnel stability. Orthogonal finite element analysis was adopted to optimize three main parameters of isolation piles. The present results indicated that the existing building changes the shape of settlement trough and increases the inter-force and deformation. Isolation piles and grouting have some control on the deformation and inter-force of supporting structures. The optimal parameters of isolation piles are 33m in length， 0.5m in longitudinal spacing， and the distance between piles and tunnel is 1.5m. This kind of optimization may provide references for the similar construction design. References | Related Articles | Metrics

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Risk Analysis of Existing Buildings During Excavation of Metro Station Using Shallow Tunneling Method ZHAO Wen， HAN Li， GUAN Yong-ping， LI Shen-gang 2013, 34 (1):  140-143.  DOI: - Abstract ( 390 )   HTML   PDF (425KB) ( 721 )   A construction safety management process was proposed based on the risk analysis theory， which is used to prevent building collapse and control the key risk factors during the metro station construction. The mechanism of the risk accidents and their prevention measures were studied based on the risk assessment of existing buildings， measures for risk control and ground consolidation. After the construction of Zhongjie Station， ground surface settlement and inclination of existing buildings were successfully controlled， which verified the reasonableness of the construction measures and the risk control standards set forth in the construction safety management process. The proposed methodology was shown to be effective in managing the risks of over-inclination and excess-settlement. References | Related Articles | Metrics

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Supply Chain Optimization and Coordination Model Based on Conditional Optimistic Expected Profit YU Chun-yun， GUAN Zhi-min， ZHAO Xi-nan 2013, 34 (1):  143-148.  DOI: - Abstract ( 699 )   HTML   PDF (300KB) ( 566 )   In view of the effects of anti-risk ability of cooperative enterprises and decision makers’ risk preferences on supply chain optimization and coordination， a concept named conditional optimistic expected profit was proposed and a power supply chain optimization and coordination mechanism with comparatively strong anti-risk abilities was introduced for further studies. First， under random demands， the conditional optimistic expected profit model of power supply chain and the optimal ordering quantity model as well as the revenue-sharing contract model based on conditional optimistic expected profit were constructed. Then， the models were analyzed with an aim to revealing the impact of suppliers’ and retailers’ anti-risk capability on supply chain coordination， the optimal ordering quantity and wholesale price， and the stability of supply chain cooperation. References | Related Articles | Metrics

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Evaluation of E-commerce Online Reputation Influenced by Seller Behaviors YU Zhao-ji， JIN Zhong， ZHAO Shuai 2013, 34 (1):  149-152.  DOI: - Abstract ( 523 )   HTML   PDF (290KB) ( 764 )   Aiming at the reputation crisis existing in such a special trading environment as electronic commerce (E-commerce) and taking seller behaviors as a unique perspective， E-commerce online reputation was systematically explored. A 14-index synthetic evaluation index system including fraud， service， product and transaction was developed， and the weight of each index was determined by using the AHP(analytic hierarchy process) method. Besides， the online reputation influenced by seller behaviors was given a synthetic assessment by means of fuzzy comprehensive evaluation. The purpose is to improve sellers’ reputation so that buyers can rest assured while shopping online， provide a sound foundation for constructing reputation evaluation models and guarantee the safe and fast development of E-commerce. References | Related Articles | Metrics