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15 April 2017, Volume 38 Issue 4 Previous Issue    Next Issue
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Information & Control

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Resilient Controller for Markov Switching Systems Under Generally Uncertain Transition Rate LIAN Lian， GAO Xian-wen， QI Wen-hai 2017, 38 (4):  457-461.  DOI: 10.12068/j.issn.1005-3026.2017.04.001 Abstract ( 622 )   HTML   PDF (353KB) ( 767 )   The problem of resilient controller design for stochastic time-delayed Markov switching systems was investigated. Transition rate of the system is generally uncertain， which is more general than the completely known rate and the partly known rate. By full considering features between each element in the generally uncertain transition matrix， a mode-dependent Lyapunov-Krasovskii functional was established， and a resilient controller was designed to ensure that the closed-loop system was stochastically stable for the Markov switching systems. A set of linear matrix inequalities (LMIs) was solved to get controller gain matrix. Finally， a numerical example was given to demonstrate the effectiveness of the results. References | Related Articles | Metrics

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Stabilization for Piecewise Homogeneous Markov Jump Systems Subject to Actuator Saturation QI Wen-hai， LI Xin， GAO Xian-wen 2017, 38 (4):  462-466.  DOI: 10.12068/j.issn.1005-3026.2017.04.002 Abstract ( 606 )   HTML   PDF (380KB) ( 839 )   The stabilization problem was studied for a class of Markov jump linear systems subject to actuator saturation， whose transition rates are piecewise homogeneous. Firstly， by using appropriate Lyapunov functional and ellipsoidal invariant set theory， the attraction domain of system in mean square sense was estimated to get the sufficient conditions with constraints of linear matrix inequalities for the closed-loop systems. Then， a convex optimization problem was solved to get the maximum domain of attraction in mean square sense and the state feedback controller gain. Finally， the effectiveness of the results was verified by a numerical example. References | Related Articles | Metrics

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Social Cloud Resource Allocation Model Based on Improved Reverse Vickrey Auction WANG Xue-yi， WANG Xing-wei， HUANG Min， WANG Zun 2017, 38 (4):  467-471.  DOI: 10.12068/j.issn.1005-3026.2017.04.003 Abstract ( 655 )   HTML   PDF (467KB) ( 858 )   Since economics is concerned with resource allocation among individuals with different objectives in human societies， a social cloud resource allocation model was proposed based on improved reverse Vickrey auction. First， the tender description and the dynamic trust calculation method were given. Then， a candidate resource provider selection method was proposed， and it was integrated into reverse Vickrey auctions to make the resource providers participating in the auction be not only friends of resource consumers， but also non-friends with high reputation. Finally， the overbooking mechanism was introduced into reverse Vickrey auction to improve the utilization of resource providers， and the allocation and pricing method was presented. The simulation results showed that the proposed model was feasible and effective. References | Related Articles | Metrics

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Map Matching Algorithm Based On Hidden Markov Model and Genetic Algorithm WU Gang， QIU Yu-jing， WANG Guo-ren 2017, 38 (4):  472-475.  DOI: 10.12068/j.issn.1005-3026.2017.04.004 Abstract ( 975 )   HTML   PDF (530KB) ( 2254 )   A new map matching algorithm was proposed on the basis of the hidden Markov model and the genetic algorithm. Firstly， the HMM probability matrix was initialized. Then， the parameters were learned by using the forward-backward algorithm， and a set of road sections was predicted by using the Viterbi algorithm. Finally， taking section sequence as population， the optimal section sequence was obtained by using the genetic algorithm. By using the taxi GPS data from Beijing in 2012 to test the traditional algorithm based on hidden Markov model and the proposed algorithm， the results showed that the traditional algorithm based on hidden Markov model has a matching accuracy below 90% and the proposed algorithm has a matching accuracy above 90%. References | Related Articles | Metrics

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Unequal Clustering Data Gathering Algorithm Based on Multiple Criteria Decision Making for WSNs SONG Xiao-ying， WEN Tao， SUN Wei， ZHANG Qi-long 2017, 38 (4):  476-480.  DOI: 10.12068/j.issn.1005-3026.2017.04.005 Abstract ( 651 )   HTML   PDF (430KB) ( 767 )   Focusing on the hot spot problem in many to one wireless sensor networks， an unequal clustering data gathering algorithm based on multiple criteria decision (UCDGAMCD) was proposed. The intuitionistic fuzzy analytic hierarchy process and multiple criteria decision making of hierarchical fuzzy integral were used to select cluster heads (CHs)， and a new cluster head competition radius was proposed to make it fit for the network scenarios with energy heterogeneous and nodes non-uniform distribution. To balance energy consumption， a routing algorithm with data ratio distribution was proposed based on residual energy of CHs and transmission energy consumption. The simulation results demonstrated that UCDGAMCD can obtain higher network lifetime in two scenarios—node uniform and non-uniform deployment. References | Related Articles | Metrics

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CDT-based Determining Method of Topological Relations for Spatiotemporal Regions BAI Lu-yi， JIA Wei-jia， CAO Xing-ru 2017, 38 (4):  481-485.  DOI: 10.12068/j.issn.1005-3026.2017.04.006 Abstract ( 637 )   HTML   PDF (449KB) ( 831 )   A CDT-based determining method of topological relations for spatiotemporal regions was investigated. The following contents were especially studied， including CDT-based spatiotemporal region representation in static spatio-temporal database， the method of dividing the spatiotemporal region in simple polygon shape into conterclockwisely directed triangle， and determining method of these spatiotemporal regions in simple polygon shape in static spatiotemporal database. The results showed that five kinds of fundamental topological relations between spatiotemporal regions， i.e.， equal， contain， overlap， disjoint and meet， can be determined with CDT. The proposed method not only effectively realizes the variety of spatiotemporal data presentation and operation， but also avoids the effect of spatiotemporal data on efficiency when the spatiotemporal data were calculated on the basis of boundary coordinates directly. References | Related Articles | Metrics

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New Compressive Sensing Algorithm Based on Block Segmentation ZHANG Na， CAO Kun， LIU Ya-xuan 2017, 38 (4):  486-492.  DOI: 10.12068/j.issn.1005-3026.2017.04.007 Abstract ( 686 )   HTML   PDF (1316KB) ( 943 )   To solve the blocking artifacts of prior block segment compressive sensing， a new reconstruction algorithm was proposed which could reduce the blocking artifacts at low complexity. When sparse representing， discrete wavelet transform (DWT) method was utilized instead of discrete cosine transform (DCT) to improve detail component of image. When measuring， the measurement matrix of each block was reweighted to improve the quality of image according to the difference frequency between each block. When reconstructing， the orthogonal matching pursuit (OMP) algorithm was used to speed up reconstruction rather than the matching pursuit (MP) algorithm. Simulation results demonstrated that the blocking artifacts could be effectively eliminated by the proposed algorithm without making any effects on reconstruction speed and memory requirement. References | Related Articles | Metrics

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Characteristics Mining and Analysis for Internet Prefix Announcements DENG Wen-ping， LI Zhu-cun， WANG Hong， GAO Xian-ming 2017, 38 (4):  492-496.  DOI: 10.12068/j.issn.1005-3026.2017.04.008 Abstract ( 703 )   HTML   PDF (536KB) ( 836 )   The BGP routing information was dogged deeply on the basis of a large number of the history of BGP routing table snapshot. A method to measure stability of prefix announcements was designed， it was verified that vast majority of routing announcement was stable， and the historical routing hijacking was short lived (without stability). A similarity measuring algorithm of prefix announcement was presented， and a large number of the history BGP routing announcements were analyzed. The results showed that the announced prefixes of most large ASes are in line with the property of self-similarity， i.e.， the same AS declaring multiple routing prefixes with certain continuity. A trustworthy set of prefix-AS mapping was extracted on the basis of these two characteristics， and a trustworthy knowledge base of BGP routing announcement was designed to provide the basis for prefix hijacking detection and routing security monitoring. References | Related Articles | Metrics

Materials & Metallurgy

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TC4 Alloy Powder Prepared by Electrode Induction Melting Gas Atomization for Laser 3D Printing CHEN Sui-yuan， DONG Huan-huan， LIU Chang-sheng， LIANG Jing 2017, 38 (4):  497-501.  DOI: 10.12068/j.issn.1005-3026.2017.04.009 Abstract ( 824 )   HTML   PDF (1524KB) ( 1323 )   TC4 alloy powders for laser 3D printing were prepared by electrode induction melting gas atomization (EIGA). The effects of different pressures on printable powder production rate， particle size， powder morphology， apparent density， flow ability and hollow powder rate were studied. The results showed that by increasing gas pressure， the printable powder production rate and powder sphericity increase， while the particle size decreases. When the gas pressure is 6.0MPa， the powder production rate is over 50%， the average particle size is below 100μm， the apparent density is 2.950g/cm3， the flow ability is 2.242g/s and the hollow powder rate is below 3%. When the gas pressure is 7.0MPa， the broken powder and hollow powder rate increase dramatically. By comparing the tensile stress-strain curve and fractograph of the samples made by the powders with different particle size under 6.0MPa， it is found that the laser 3D printing sample using TC4 alloy powders ranging from 50 to 100μm has better strength and toughness， corresponding to the tensile strength of 907.7MPa and the ductility of 15.3%. References | Related Articles | Metrics

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V-N Microalloying Q550D High-Strength Mid-Thick Steel Plate QI Xiang-yu， ZANG Miao， HU Jun， DU Lin-xiu 2017, 38 (4):  502-506.  DOI: 10.12068/j.issn.1005-3026.2017.04.010 Abstract ( 623 )   HTML   PDF (2319KB) ( 1235 )   The controlled rolling and controlled cooling test was conducted on V-N microalloying Q550D high strength steel plate. The microstructures at different positions along the thickness of the steel were studied and the mechanical properties were tested. The results showed that the microstructure of V-N microalloying Q550D plate is composed of polygonal and acicular ferrites. From the surface to the center of the test sample， the average grain size increases， while the mass fraction of acicular ferrite decreases. It was also observed that the size of (Ti，V)N precipitates is 20~30nm and the size of V(C，N) precipitates is smaller than 10nm， and both precipitates distribute dispersedly in the matrix of polygonal and acicular ferrites. The yield strength， tensile strength， elongation and impact work at -20℃ of test steel were 651MPa， 733MPa， 18% and 170J， respectively. The fine grain strengthening， precipitation strengthening， dislocation strengthening， solid solution strengthening and acicular ferrite strengthening were the major mechanisms of strengthening. Meanwhile， the role of fine grain， low C component and the formation of acicular ferrite were the major mechanisms of toughening. References | Related Articles | Metrics

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Effects of Casting Speed and Mischmetal on Microstructure and Mechanical Properties of Al-23%Si Alloy WANG Dong-tao， ZHANG Hai-tao， HAN Xing， CUI Jian-zhong 2017, 38 (4):  507-512.  DOI: 10.12068/j.issn.1005-3026.2017.04.011 Abstract ( 749 )   HTML   PDF (3474KB) ( 831 )   The effects of different direct chilling casting speed and mischmetal (i.e.，Ce and La elements) addition on microstructure and mechanical properties of Al-23%Si were investigated. The results showed that when the casting speed increases from 100mm/min to 250mm/min， the segregation of primary Si is restricted effectively， the distribution of primary Si becomes more uniform in different positions of the ingot， the size of primary Si is greatly decreased from 71.4μm to 40.9μm and the segregation of eutectic Si is also reduced. With an addition of 0.5% mischmetal， the size of eutectic Si refines and its morphology changes from flake-like shape to short rod-like one. Both hardness and tensile strength increase with the increase of DC casting speed and the addition of mischmetal. References | Related Articles | Metrics

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Developing and Application of Crown Control Model for Medium Breadth Hot Rolled Strip GONG Dian-yao， XU Jian-zhong， SONG Xiang-rong， YU Si-qing 2017, 38 (4):  512-516.  DOI: 10.12068/j.issn.1005-3026.2017.04.012 Abstract ( 719 )   HTML   PDF (882KB) ( 1218 )   Taking a certain new built medium breadth hot rolled strip mill as the objection， the principal influencing factors of strip center crown were analyzed. It was presented the predictive model of strip crown， the calculating model of thermal crown and wear and the model of the feedback control for center crown and flatness. In the rolling process of the typical products， the SIN curves of 7-standed work rolls barrel were designed. According to the measured data of strip rolled in site， it was plotted the relative crown profile under the condition of even force distribution and the distribution curve of relative crown of strip in finishing mill. Measured data obtained by multi-functional profile and shape meter showed that 100 percent of the finishing crown of strip was located in the range of (40±20)μm and the flatness of 0I with the tolerance of ±10I was more than 98 percent along strip length. References | Related Articles | Metrics

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Phase Transformation and Non-isothermal Oxidation Kinetics of Hongge Vanadium-Bearing Titanomagnetite LI Wei， FU Gui-qin， CHU Man-sheng， ZHU Miao-yong 2017, 38 (4):  517-521.  DOI: 10.12068/j.issn.1005-3026.2017.04.013 Abstract ( 877 )   HTML   PDF (713KB) ( 857 )   The existence form and phase transformation of Hongge vanadium-bearing titanomagnetite (HVTM) pellets during oxidation process were investigated based on the study of fundamental characteristics of the ore. The non-isothermal oxidation kinetics of HVTM was also studied by the thermogravimetry. The results indicated that the HVTM is high chromium vanadium-bearing titanomagnetite with 1.48wt% Cr2O3 and its crystal stock strength is 625 N， the ore mainly consists of magnetite， titanomagnetite， coulsonite and chromite. The HVTM oxidizes slowly below 300℃. Phase transformation behavior of valuable elements is as follows: Fe3O4→Fe2O3， Fe2VO4→(Cr0.15V0.85)2O3， Fe2.75Ti0.25O4→FeTiO3→Fe9TiO15， FeCr2O4→(Fe0.6Cr0.4)2O4， Fe0.7Cr1.3O3 and (Cr0.15V0.85)2O3.The results of non-isothermal oxidation kinetics of HVTM showed that when the HVTM oxidized at 220~380℃， 380~500℃ and 500~800℃ with a heating rate of 10℃·min-1， the activation energy are 47.02， 14.95 and 30.36kJ·mol-1， respectively. References | Related Articles | Metrics

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Simulation of Natural Convection in Square Porous Cavity Based on Chebyshev Spectral Method CHEN Yuan-yuan， LI Ben-wen， ZHANG Jing-kui 2017, 38 (4):  522-526.  DOI: 10.12068/j.issn.1005-3026.2017.04.014 Abstract ( 737 )   HTML   PDF (973KB) ( 943 )   The Chebyshev spectral collocation method (CSCM) was used to simulate natural convection in the square porous cavity under a local thermal equilibrium condition. Using the Chebyshev-Gauss-Lobatto collocation points， the dimensionless govering equations can be spatially discredited. The matrix diagonalization method was used to solve these discredited equations. The simulation results were in well agreement with the existing data. Meanwhile， the exact solutions were further constructed to valid the method and the CSCM effectiveness was proved. Finally， the effects of Rayleigh number on the streamlines， the isotherms and the Nusselt number were studied based on the CSCM simulations. References | Related Articles | Metrics

Mechanical Engineering

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Theoretical Study on Visualization of Cylindricity Error CHEN Li-jie， ZHANG Ming-yao， KANG Ya-dong 2017, 38 (4):  527-530.  DOI: 10.12068/j.issn.1005-3026.2017.04.015 Abstract ( 836 )   HTML   PDF (419KB) ( 862 )   The basic theory of producing cylindricity error graph was studied， and a mathematical model for visualization of cylindricity error was established. The theory of computer graphics and three-dimensional wireframe models were used to realize the display of extracted integral feature， associated integral feature and associated derived feature of the measured cylinders. Axonometric projection transformation was adopted to fulfill the realization of basic geometric shapes. The space hidden method was used to solve the problem of geometrical graph hidden. According to the standard definition of cylindricity error， the mathematical model for cylindricity error graphic display was established. On the basis of theoretical study， software was developed to realize visualization of cylindricity error on the platform of LabWindows/CVI. References | Related Articles | Metrics

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Optimization Method of Cutting Process Parameters for Dicing Saw SUN Hong-chun， WANG Hong-bao， XU Yong， XIE Li-yang 2017, 38 (4):  531-535.  DOI: 10.12068/j.issn.1005-3026.2017.04.016 Abstract ( 794 )   HTML   PDF (450KB) ( 1003 )   The cutting process parameters of dicing saw are difficult to get in actual production， an optimization method was thus proposed to establish the best cutting parameters based on genetic algorithm of Matlab. The scope of the cutting process parameters was selected by avoiding the natural frequency of every order， and the root mean square of the axis vibration was used as the evaluation index. The regression equation was established between parameters of vibration and cutting processes by regression orthogonal design. The best cutting parameters according to the minimum vibration were obtained by using the Matlab genetic algorithm to make iterative optimization for the regression equation. The optimization result was verified by experiments. References | Related Articles | Metrics

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Combustion Characteristics of Micro-lobed Burner XIE Yi， ZHONG Chen， RUAN Deng-fang， LIU Kun 2017, 38 (4):  536-541.  DOI: 10.12068/j.issn.1005-3026.2017.04.017 Abstract ( 631 )   HTML   PDF (2117KB) ( 822 )   A 3D simulation method was used to simulate the flow and combustion of micro-lobed burner and splitter burner， and the influence law of equivalence ratio between methane and oxygen on combustion characteristics was studied. The results showed that the streamwise vortices and augmentation in the mixing area between methane and oxygen could improve the mixing between fuel and oxidant， which can thus strengthen combustion to increase the combustion efficiency and temperature. Besides， although the combustion efficiency and temperature of micro-lobed burner are higher than that of the splitter burner， the combustion temperature and efficiency differences between these two burners at the same position go down as equivalence ratio decreases. References | Related Articles | Metrics

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Micro-milling Forces Test for Single Crystal Nickel-Based Superalloy GAO Qi， GONG Ya-dong， ZHOU Yun-guang， WEN Xue-long 2017, 38 (4):  542-546.  DOI: 10.12068/j.issn.1005-3026.2017.04.018 Abstract ( 685 )   HTML   PDF (565KB) ( 926 )   Taking the single crystal nickel-based superalloy DD98 as research object， the material removal mechanism of single crystal superalloy was analyzed from its microstructure. The glide plane of DD98 is its close-packed plane 111， while the glide direction is its close-packed direction <110> with minimum resistance force and easy slip. The orthogonal experiment was implemented for micro-milling single crystal nickel-based superalloy DD98 by using two-edged micro-milling tool. The effect of cutting parameters on the micro-milling forces was obtained through range analysis. The result showed that the influence of spindle speed is the greatest， the feed rate is the secondary， and the milling depth is the smallest affecting factor. The ideal cutting parameters were obtained using minimum micro-milling forces， i.e.， with the spindle speed of 36000r/min， milling depth of 5μm and the feed rate of 20μm/s. The reasons affecting on micro-milling forces were deeply analyzed， and the test results may provide certain theory reference and test basis for understanding the micro-milling mechanism of single crystal superalloy. References | Related Articles | Metrics

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Damping Characteristic Analysis of Cantilever Beam with Straight Crack MA Hui， WU Shuang， ZENG Jin， ZHANG Wen-sheng 2017, 38 (4):  546-550.  DOI: 10.12068/j.issn.1005-3026.2017.04.019 Abstract ( 710 )   HTML   PDF (776KB) ( 938 )   Taking cracked cantilever beam system as the research project， a finite element model of straight-cracked cantilever beam was established on the basis of the ANSYS by using beam， plane and contact elements. The contact elements were used to simulate breathing effects of crack， and the effectiveness of the as-proposed model was verified by comparing with the natural frequency in the literature. Under impulsive and sinusoidal excitation， the effects of friction on vibration characteristics were analyzed based on the model. The change rules of system damping ratio and natural frequency with the crack depth and crack position were analyzed with ignoring friction. The results showed that the interface friction of crack has few effects on system vibration， and damping ratio could be used as a parameter of crack detection to some extent. References | Related Articles | Metrics

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Control Strategy Optimization Method Based on Driving Cycle Recognition for HEV LIAN Jing， FAN Wu-ming， LI Lin-hui， YUAN Lu-shan 2017, 38 (4):  551-556.  DOI: 10.12068/j.issn.1005-3026.2017.04.020 Abstract ( 698 )   HTML   PDF (818KB) ( 859 )   Taking a parallel hybrid bus as research object， four kinds of typical working condition models were established， and the ant colony optimization algorithm was used to optimize the charge and discharge equivalent factor for each working condition in minimal equivalent fuel consumption control strategy. The relation between road gradient and adjustment of battery SOC target range was analyzed， and the corresponding gradient adaptive module was designed. A control strategy optimization method was proposed based on driving cycle recognition for HEV. The results of simulation and comparison analysis under typical working conditions showed that the method has very well driving condition adaptability， and its fuel economy is significantly higher than that of other several typical HEV control strategies. References | Related Articles | Metrics

Resources & Civil Engineering

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Effect of Siderite and Dolomite on Flotation of Quartz LI Dong， YIN Wan-zhong， YAO Jin， CAO Shao-hang 2017, 38 (4):  557-561.  DOI: 10.12068/j.issn.1005-3026.2017.04.021 Abstract ( 774 )   HTML   PDF (556KB) ( 886 )   Flotation test， adsorption test， and solution chemical calculations were used to investigate the effect of siderite and dolomite on quartz flotation in sodium oleate flotation system. The results of flotation and adsorption tests showed that the effect of siderite on quartz flotation is related to the dissolved siderite species and starch， and siderite significantly influences flotation of quartz in the presence of starch. The negative effect of dolomite on quartz flotation could be whittled by increasing the dosage of sodium oleate. The solution chemical calculations indicated that dissolved siderite species might convert the initial surface of active quartz to CaCO3 precipitates which can be easily depressed by starch， while the dolomite dissolution is restrained by calcium ions in the solution， which might explain the difference of effects on quartz flotation between dissolved siderite species and dissolved dolomite species. References | Related Articles | Metrics

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Comparative Test of Stirred Mill and Ball Mill LI Yan-jun， GUO Wang， WANG Shao-xing， LIU Yan-ling 2017, 38 (4):  562-566.  DOI: 10.12068/j.issn.1005-3026.2017.04.022 Abstract ( 789 )   HTML   PDF (508KB) ( 923 )   The particle size characteristics， specific productivity rate and energy consumption were studied in the grinding process of stirred mill and ball mill. The results showed that the product of stirred mill was more uniform than that of ball mill， and the mass fractions of fine grain and coarse particle of ball mill are higher than that of stirred mill. The straight line and exponential curve were respectively used to fit the relationships between different grinding particle size and specific productivity under stirred mill and ball mill， and the specific production rate of ball mill decreases obviously with the decrease of mill feed size. The equation formula proposed by Walker et al was used to fit the relationship between mill feed size and energy consumption， and the energy consumption growth rate of the stirred mill is much smaller than that of ball mill. Stirred mill has obvious advantages over ball mill in the process of fine grinding and ultra-fine grinding. References | Related Articles | Metrics

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Risk Control on Life Loss During Tailings Dam Break ZHENG Xin， AN Hua-ming， ZHANG Fang， XU Kai-li 2017, 38 (4):  566-570.  DOI: 10.12068/j.issn.1005-3026.2017.04.023 Abstract ( 619 )   HTML   PDF (444KB) ( 834 )   The failure probability of tailings dam， evolution simulation of sand flow downstream of dam break， the loss of life ，the life loss risk acceptable criteria of the tailings dam break， and the best safety investment to save lives were studied. The tailings dam slope failure function and the personal life acceptable risk criteria of tailings dam break were established. Taking a tailings dam as an example， a case study was carried out. The optimal safety investment for life saving was calculated to be 3.9 million RMB. Compared the standard of the United States with China′s current industrial injury death compensation， it is suggested that the relevant departments of our country should improve the compensation standard for work-related injuries. References | Related Articles | Metrics

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Landslide Sensitivity Based on K-PSO Clustering Algorithm and Entropy Method RUAN Yun-kai， ZHAN Jie-wei， CHEN Jian-ping， LI Yan-yan 2017, 38 (4):  571-575.  DOI: 10.12068/j.issn.1005-3026.2017.04.024 Abstract ( 612 )   HTML   PDF (1037KB) ( 823 )   The K-PSO clustering algorithm and entropy method were introduced to establish a sensitivity analysis model for landslide. The 22 typical landslides located in Xulong hydropower station reservoir area were investigated. Eight major factors including rock mass structure， slope structure， fault distance， signs of deformation， slope height， average gradient， induced earthquake and submerged ratio were determined for landslide sensitivity analysis. The weights of major factors determined by the entropy method are 0.152， 0.178， 0.035， 0.106， 0.106， 0.169， 0.193， 0.061， respectively. Sensitivity analysis results based on K-PSO clustering algorithm showed that among the 22 landslides， 8 landslides are evaluated as low sensitive， 9 as moderate， 4 as severely sensitive and one as extremly sensitive. Compared with the in-situ observations， the evlauated level of sensitivity of the 22 landslides agree very well with the actual development of the landslides. The proposed K-PSO method is effective for landslide sensitivity analysis in Xulong hydropower station reservoir area. References | Related Articles | Metrics

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Large-Scale Model Test on Rainfall Induced Colluvium Slope Failure CHEN Yu-long， HUANG Dong 2017, 38 (4):  576-580.  DOI: 10.12068/j.issn.1005-3026.2017.04.025 Abstract ( 674 )   HTML   PDF (1060KB) ( 952 )   A large-scale colluvium model test was conducted on rainfall induced slope failure to investigate the laws of the seepage， deformation and failure of colluvium slope under rainfall conditions. Acoustic emission as a criterion of warning was discussed. Results showed that after the wetting front has reached the corresponding measuring point， the volume fraction of water increases continually， and the water level begins to increase untill the volume fraction of water reaches its peak value. The displacement at the top of the slope is large and is small at the toe， and the increase of the displacement of the slope has an acceleration process before failure occurs. The tilt angle increases suddenly when failure occurs. The acoustic emission accounts increase slowly at first and sharply afterwards. Slope failure is strongly linked to surface runoff and fine particle migration. References | Related Articles | Metrics

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Power-Law Distribution of Acoustic Emission Energy of Coal Samples in Brazilian Test REN Song， ZHAO Yun-feng， ZHANG Jun-wei， JIANG Xiang 2017, 38 (4):  581-585.  DOI: 10.12068/j.issn.1005-3026.2017.04.026 Abstract ( 716 )   HTML   PDF (851KB) ( 837 )   In order to study the acoustic emission energy distribution and the feasibility of fiber bundle model based on mean field theory in numerical simulation on acoustic emission characteristics during the tensile damage process of coal， Brazilian tests on coal specimen were carried out under different loading rates. The results showed that the acoustic emission energy probability density distribution follows a power-law distribution and its distribution exponents are close to the predicted value of the mean field theory model. At the same time，the acoustic emission energy probability density distribution also follows a power-law distribution within different time intervals. The test results are similar to numerical results of the mean field theory based fiber bundle model， and provide a basis for the confirmation of the fiber bundle model parameters. References | Related Articles | Metrics

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Creep Characteristic of Carbonaceous Slate and Its Constitutive Model Under Triaxial Compression WANG Yong-gang， DING Wen-qi， WANG Zhe-chao， ZONG Zhi 2017, 38 (4):  586-590.  DOI: 10.12068/j.issn.1005-3026.2017.04.027 Abstract ( 823 )   HTML   PDF (786KB) ( 1026 )   Triaxial compression creep tests were performed on carbonaceous slate samples obtained from Muzhailing tunnel of Lanzhou-Chongqing railway in order to understand the creep characteristics of carbonaceous slate with different angle between bedding planes and axial load. Based on the test results， a creep model was proposed to describe the transversely isotropic creep behavior of the carbonaceous slate， which needs more parameters in the creep potential function to describe the transversely isotropic creep behavior than in the conventional potential function. A method for the determination of creep parameters was developed using back analysis， which is helpful in reducing the number of creep tests needed to determine the creep parameters and is applicable in practice. This study contributes to the understanding of the transversely isotropic behavior of rocks and to the design of the lining system in the transversely isotropic stratum. References | Related Articles | Metrics

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Mathematical Prediction on Effect of Tailing Discharge of Open-Pit on Stability of Underground Mined Out Area SHI Xiu-zhi， CHEN Jia-yao， ZHOU Jian， QIU Xian-yang 2017, 38 (4):  591-597.  DOI: 10.12068/j.issn.1005-3026.2017.04.028 Abstract ( 513 )   HTML   PDF (2387KB) ( 847 )   To reveal the impact of the height of the tailing dry stacked gangue (H) on the span of double gob area (D) and the roof thickness (h)， the simulation software FLAC3D was used to simulate the excavation process of the double gob area of different spans during the tailing-backfilling process. The stress， plastic zones and the displacement of monitoring points of double gob area were analyzed by combining with the hyperbolic fitting equations， traditional failure criterion and the thickness reduction methods. When D is kept constant， tensile and compressive stress and the plastic zone area increase with the increase of H， and the displacement of all monitoring points increase significantly when the span is larger than 20m. When H is kept constant， the displacement and the plastic zone area increase with the increase of D， and it can be quantitatively predicted that when the span is up to 26m， the critical damage height of tailing dry stacked gangue is 182.44 and 189.85m， respectively. When D and H are changed， the plastic zones of the double gob area take on a butterfly-shape， and the plastic zone area of the upper gob is greater than that of the lower part. A cutting-through failure will occur when the span exceeds 20m and the tailing height exceeds 150m. References | Related Articles | Metrics

Management Science

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Fluctuation Relationship Between Land and House Prices Based on Simultaneous Equation TANG Kai， ZHUANG Xin-tian， LU Pan-pan， LI Xiao-qing 2017, 38 (4):  598-603.  DOI: 10.12068/j.issn.1005-3026.2017.04.029 Abstract ( 611 )   HTML   PDF (380KB) ( 887 )   A simultaneous equation model for the relations of urban real estate prices in our country was built， and parameter estimation of national key sample cities was given according to the quadratic least squares. The results indicated that simultaneity and interplay exist between land and house prices. The number of population has a great influence on land price. Per capita disposable income and real estate development investment raise the house price， but house sales area is quite the reverse. House price lag greatly affects house price. The expectation of fluctuating prices impacts on the investor sentiment and leads to the changes of house price. References | Related Articles | Metrics

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Patient Routing Based on Beds Fairness from Outpatient Department to Internal Wards CHEN Dan ， ZHU Hua-bo ， LUO Xing-gang 2017, 38 (4):  604-608.  DOI: 10.12068/j.issn.1005-3026.2017.04.030 Abstract ( 702 )   HTML   PDF (613KB) ( 748 )   Based on theoretical analysis of flowchart and mass patient flow data， an inverted-V model with single patient queue and several heterogeneous server pools was established to describe patient routing allocation process. With the goal of routing allocation fairness for the beds of internal wards， the application of Markov process of randomized most-idle (RMI) routing policy in the inverted-V model was analyzed. The occupied and service rates of sever pools under different routing policies were obtained， and the routing policy fairness was analyzed theoretically. The experimental results showed the occupied and service rates for different server pool under RMI policy are more balanced than that of the average allocation policy. References | Related Articles | Metrics