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15 May 2016, Volume 37 Issue 5 Previous Issue    Next Issue
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Information & Control

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Stereo Matching Algorithm Based on Improved Patchmatch and Slice Sampling Particle Belief Propagation LI Jing-jiao， MA Li， WANG Ai-xia， MA Shuai 2016, 37 (5):  609-613.  DOI: 10.12068/j.issn.1005-3026.2016.05.001 Abstract ( 882 )   HTML   PDF (317KB) ( 1171 )   The high erroneous results of the stereo matching occur at the following three cases where there are depth discontinuity region， the slanted surface or the non-fronto-parallel surface. A stereo matching algorithm was proposed based on the improved Patchmatch and slice sampling particle belief propagation. An edge-preserving similarity function of the Patchmatch was defined. Then， a model of the depth estimation for the non-fronto-parallel surface was introduced. The nearest neighbor search was replaced with the particle belief propagation， and the target distribution was approximated with a finite set of particles. At the same time， the sampled particles from the belief distribution was typically done by using slice sampling Markov chain Monte Carlo method to solve the particle update problem. The experiments on the Middlebury indicate that the mismatching at the depth discontinuity region can be reduced， and the match accuracy for the slanted surface and the non-fronto-parallel surface can be improved. References | Related Articles | Metrics

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Real-Time Tracking and Registration Algorithm of Scenarios of Augmented Reality Based on Improved Random Fern ZHAO Yue， LI Jing-jiao， LI Hai-peng， YANG Dan 2016, 37 (5):  614-618.  DOI: 10.12068/j.issn.1005-3026.2016.05.002 Abstract ( 517 )   HTML   PDF (506KB) ( 772 )   Because of the slow speed of tracking and registration on scenarios of augmented reality， an algorithm was proposed based on the improved random fern on tracking and registration of augmented reality. The proposed algorithm has the offline training section and the online tracking section. A classifier based on the embedded fern was proposed. In the developed classifier， a supervised dimensionality reduction method and all possible information were used. What’s more， it was also used for the feature matching， and then camera pose was computed and virtual objects were rendered and registered. Experimental results show that the proposed algorithm is superior to other algorithms on the average classification accuracy. The average processing time of each frame is about 34.22ms， which can almost meet the real-time. References | Related Articles | Metrics

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Bilinear Map-based Public Verifiable Outsourced Computation Scheme LI Fu-xiang， HUO Jian-qiu， LIN Mu-qing， ZHOU Fu-cai 2016, 37 (5):  619-623.  DOI: 10.12068/j.issn.1005-3026.2016.05.003 Abstract ( 592 )   HTML   PDF (227KB) ( 924 )   There are two shortcomings for the existing verifiable computation schemes. One is that only the owner who outsourced the computation can verify the result， and the other is when the owner authorizes other users to verify the result， he has to send his secret key to all the authorized users. In order to overcome the problems， an outsourced computation model was proposed which supports the public verification. The description and security model were formalized and a publicly verifiable outsourced computation scheme， which is based on the bilinear map and contains three entities， was also presented. The algorithm implementation and the communication protocol were also described in details. The verification phase in the scheme does not need the owner’s secret key so it can be publicly verifiable. The scheme can be proved to satisfy unforgeability in the security model， and the security can be reduced to the hardness of the l-SBDH problem. References | Related Articles | Metrics

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Multi-core Parallel Substring Matching Algorithm Using BWT WANG Jia-ying， WANG Bin， LI Xiao-hua， YANG Xiao-chun 2016, 37 (5):  624-628.  DOI: 10.12068/j.issn.1005-3026.2016.05.004 Abstract ( 757 )   HTML   PDF (827KB) ( 1085 )   In order to solve the problem that P-BWT (Burrows-Wheeler transform) could only support short queries， and work on a uniprocessor， a multi-core parallel exact matching algorithm was proposed which any query length could be supposed. Firstly， the search process on P-BWT index was modified. When a query spans multiple data fragments， it first searches on the last segment， then verifies on the other segments. Further， a parallel algorithm was proposed to reduce the iterations in the search and verify process. Finally， the experimental study show that using the proposed algorithm， the substring matching task could be accomplished efficiently in parallel manner. References | Related Articles | Metrics

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Popularity-Optimal Path Search Based on Time Constraint BAO Jin-ling， WANG Bin， LIU Gang， YANG Xiao-chun 2016, 37 (5):  629-633.  DOI: 10.12068/j.issn.1005-3026.2016.05.005 Abstract ( 594 )   HTML   PDF (352KB) ( 752 )   When the permitted time is not enough to visit all attractions in any path， the path satisfying the constraints could not be found by the existing search methods. An approximation algorithm PSScaling to solve this problem was presented， making a choice on any node (visit or pass by) according to the tradeoff between permitted time and popularity score of attractions， and selecting the best combination of attractions to access in the same path. The experimental results on real data sets reveal that the proposed algorithm is able to find the approximate optimal path efficiently. References | Related Articles | Metrics

Materials & Metallurgy

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EEG Classification Based on Least Squares Support Vector Machine LIU Chong， YU Qing-wen， LU Zhi-guo， WANG Hong 2016, 37 (5):  634-637.  DOI: 10.12068/j.issn.1005-3026.2016.05.006 Abstract ( 696 )   HTML   PDF (332KB) ( 963 )   The classification of mental states based on motor imagery(MI) electroencephalograph(EEG) signal was investigated. All the states were classified according to the phenomenon of event-related synchronization and event-related desynchronization. The band power of the MI EEG signal was extracted as the input feature and then classified by using LS-SVM. The final classification accuracy is 92%， which shows that LS-SVM performs well for the classification of the band power feature of MI EEG signal. And compared to the standard SVM， the performance of LS-SVM is as good as that of the standard SVM， but has some advantage in computing time. References | Related Articles | Metrics

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Flow Stress Modeling in Low Carbon Titanium-Vanadium Microalloyed Steel SHEN Ji-cheng， JIA Tao， LIU Zhen-yu 2016, 37 (5):  638-642.  DOI: 10.12068/j.issn.1005-3026.2016.05.007 Abstract ( 553 )   HTML   PDF (548KB) ( 787 )   Using the single-pass compression experiment， the stress-strain behavior of austenite in a low carbon titanium-vanadium microalloyed steel was studied. The investigated temperature and strain rate were in a range of 1 173~1 373K and 0.1~10s-1， respectively. The deformation activation energy Qdef and Zener-Hollomon parameter were determined according to Akben’s work which quantified the drag effect of solutes on the dynamic recrystallization. Based on Jonas’ analysis， the recovery parameters r and r’， yield stress σ0， saturation stress σsat， and the critical stress for dynamic recrystallization σc were formulated as functions of Z-parameter and then the kinetics for dynamic recrystallization was derived. Eventually， a flow stress model was established. References | Related Articles | Metrics

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Modeling the Effect of Nb on Austenite→Ferrite Phase Transformation Kinetics LIU Xue-feng， JIA Tao， ZHU Ben-qiang 2016, 37 (5):  642-646.  DOI: 10.12068/j.issn.1005-3026.2016.05.008 Abstract ( 622 )   HTML   PDF (534KB) ( 1028 )   In thermal simulation tests， the austenite with the same grain size but different solute Nb% was obtained by holding at austenite region with various times. The dilation curve was recorded when the sample was cooled to room temperature with the cooling rate of 1~5K/s. Originating from Rios’ theoretical deduction， a modeling approach based on the JMAK(Johnson-Mehl-Avrami-Kolmogorov) equation and additivity rule was developed. The kinetic model of austenite to ferrite phase transformation under different solute Nb% was established. The results suggest that the exponential n is not affected by the solute Nb%， whereas the kinetic parameter k decreases with increasing solute Nb% that is an enhanced solute drag effect. References | Related Articles | Metrics

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Crystal Plasticity Finite Element Simulation of Slip System Evolution in Pure Copper Foil Rolling CHEN Shou-dong， LIU Xiang-hua， LIU Li-zhong， SUN Xiang-kun 2016, 37 (5):  647-652.  DOI: 10.12068/j.issn.1005-3026.2016.05.009 Abstract ( 786 )   HTML   PDF (1756KB) ( 1279 )   The distributions of the stress， strain and slip systems in pure copper foil rolling with the same reduction were simulated by the rate-dependent crystal plasticity theory and Voronoi polycrystalline model with respect to specimen dimension， grain orientation and its distribution to quantitatively evaluate the influence of thickness on inhomogeneous deformation behavior of foil rolling at mesoscale. The simulated stress-strain curves agree well with the experimental results. The simulation results reveal that the deformation behavior in the polycrystalline aggregate is inhomogeneous not only in intracrystalline but also in intergranule with a 20% reduction in foil rolling. The foils are composed of only a single layer grain across thickness， the grains with different sizes， shapes and orientations are unevenly distributed in the foil， the misorientation of neighboring grains and the property of active slip systems. References | Related Articles | Metrics

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Effects of Rotor Rotation Speed and Gas Flow Rate on the Degassing Efficiency of 2524 Aluminum Alloy in Rotary Degassing Process ZUO Yu-bo， LIN Yue， KANG Yi-yao， CUI Jian-zhong 2016, 37 (5):  653-657.  DOI: 10.12068/j.issn.1005-3026.2016.05.010 Abstract ( 845 )   HTML   PDF (904KB) ( 1166 )   The effects of rotor rotation speed and inert gas flow rate on rotary degassing efficiency are studied by using water simulation and direct aluminum melt degassing experiments and the mechanisms have been further discussed. The results show that the rotor rotation speed and gas flow rate in the rotary degassing process greatly affect the degassing efficiency. With increasing rotor rotation speed， the bubble size decreases and the affected region becomes larger， therefore the gas removal rate increases. When the gas flow rate in a certain range increases， the number of bubbles increases， corresponding to an improved gas removal efficiency. However， when the gas flow rate raises too high， the degassing efficiency decreases due to the reduce of affected region， which comes from the isolation of the gas layer formed between the rotor and melt. In the study， the appropriate parameters of the rotation speed and inert gas flow rate in the process are 550~690r/min and 1~3L/min， respectively. References | Related Articles | Metrics

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Research and Application of Burden Charging Model for Large Blast Furnace LI Zhuang-nian ， LIU Zheng-gen， CHU Man-sheng， CHEN Shu-wen 2016, 37 (5):  658-662.  DOI: 10.12068/j.issn.1005-3026.2016.05.011 Abstract ( 734 )   HTML   PDF (484KB) ( 1435 )   A new method of calculating charging profile was proposed which based on the mechanism of material movement in the charging process and improved the correction method of material flow path. As the model takes into account the effects of charge characteristics， coke collapsing and other factors on the charging profile， it makes the simulation results more accurate in practice. When its setup combines with industrial conditions， the model can calculate the parameters of charging profile， radial distribution of material， radial O/C rate and etc. under different charging systems. The area coke load index of blast furnace (BF) has been defined which makes it more evident when comparing the difference of various charging system. Using the model， some existing problems in large BF could be solved and also the practical suggestion can be proposed for the actual production. The model could further provide theoretical guidance of adjusting charging system for BF operators. References | Related Articles | Metrics

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Numerical Simulation Research on Heat Transfer in Particle Flow Round Tubes YU Qing-bo， PENG Jia-yan， REN Hui-lai， LIU Jun-xiang 2016, 37 (5):  663-667.  DOI: 10.12068/j.issn.1005-3026.2016.05.012 Abstract ( 701 )   HTML   PDF (697KB) ( 923 )   At present， air is a commonly-used heat transfer medium to recover waste heat of slag particles in blast furnace (BF) after dry granulation， which has a low thermal efficiency owing to its low specific heat capacity. Therefore， using gravity bed waste heat boiler to recover waste heat in the high temperature BF slag particles was proposed. Considering the particles as continuous viscous flow， a three dimensional numerical model was built to simulate the heat transfer of BF slag particles flowing around tubes based on the CFD software of Fluent. The effects of the inlet velocity of particles and water， and the inlet temperature of water on the efficiency of heat exchanging in waste heat boiler were investigated. The simulation results show that the efficiency of heat transfer improves with increasing the inlet velocity of particles and water， and the heat recovery rate of the former drops. However， when the inlet temperature of water increases， the heat transfer coefficient keeps invariant and the heat recovery rate reduces. References | Related Articles | Metrics

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Thermodynamics Analysis of Slag Deoxidization with Different Deoxidizers During Electroslag Remelting Process HOU Dong， JIANG Zhou-hua， DONG Yan-wu， ZHOU Wei-ji 2016, 37 (5):  668-672.  DOI: 10.12068/j.issn.1005-3026.2016.05.013 Abstract ( 676 )   HTML   PDF (659KB) ( 923 )   A thermodynamics model for deoxidation in industrial pure iron system with Al， CaSi， CaSiBa as deoxidizers was developed by calculating the equilibrium mass fractions of Si， Al in steel based on the thermodynamics equilibrium and mass conservation. The results from the thermodynamics model can be in a good agreement with the experimental results. The deoxidizers of Al， CaSi and CaSiBa can make the FeO content in slag decrease to 0.04%， 0.08% and 0.08%， respectively. Meanwhile， not only can Al make the oxygen potential of slag decrease to the lowest value， but also its deoxidizing product of Al2O3 change little， which shows the excellent performance of stabilizing slag composition. References | Related Articles | Metrics

Mechanical Engineering

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Static Friction Coefficient Fractal Model of Joint Surfaces with Elastic-Plastic Beformation Considered LI Xiao-peng， WANG Xue， YUN Hai-meng， AN Lian-chui 2016, 37 (5):  673-677.  DOI: 10.12068/j.issn.1005-3026.2016.05.014 Abstract ( 707 )   HTML   PDF (594KB) ( 973 )   Based on the traditional M-B fractal model， the contact fractal model of static friction coefficient with the elastic-plastic deformation was established. At the same time， the model without the elastic-plastic deformation considered was also built as a comparison. The results show that the static friction coefficients with elastic-plastic deformation considered is greater than that without. The static friction coefficient is positively correlated with the normal load and material parameters， but negatively with the fractal scale parameters. For 1.1≤D≤1.5， the static friction coefficient and the fractal dimension are positively correlated， while for 1.5≤D≤1.9， they are negatively correlated. References | Related Articles | Metrics

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Milling Force Coefficient Identification of Ball-End Milling Based on Instantaneous Milling Forces LI Bai-chun， WANG Zhen-yu， WANG Guo-xun， WANG Wan-shan 2016, 37 (5):  678-682.  DOI: 10.12068/j.issn.1005-3026.2016.05.015 Abstract ( 816 )   HTML   PDF (993KB) ( 924 )   In order to realize the milling force prediction of multi-axis milling， a new method based on the instantaneous milling force values was presented to obtain the specific milling force coefficients of ball-end milling. The instantaneous coordinate system of cutter was set up to precisely describe the position and posture of cutter during the process of milling. And on this basis the universal prediction model of milling， which includes the models of the edge length， the chip width in each cutting edge discrete element and the unreformed chip thickness， was established. Then according to the universal prediction model， the identification model of milling force coefficients based on the instantaneous milling force values was derived. The presented method was validated by experiments of milling force coefficients identification and the simulations of milling force. References | Related Articles | Metrics

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Intelligent Multi-pipes Layout for Aero-Engine Based on CAFSC Algorithm ZHANG Yu， BAI Xiao-lan 2016, 37 (5):  683-687.  DOI: 10.12068/j.issn.1005-3026.2016.05.016 Abstract ( 596 )   HTML   PDF (948KB) ( 926 )   For the issue of multi-pipes layout for aero-engine， the chaos artificial fish swarm algorithm-based co-evolutionary (CAFSC) algorithm was applied to the intelligent multi-pipes layout， utilizing the idea of co-evolution and combining with the chaos artificial fish algorithm. In the algorithm， every pipe was considered as a population. On the one hand， every population was evolved independently by the chaos artificial fish swarm algorithm. On the other hand， choosing the representation to create the system model， the optimal pipe-routing was achieved by means of mutual collaboration. Facing the increasing pipes， the algorithm avoided the combination explosion， and optimized the pipe-routing on the whole regardless of the layout sequence. References | Related Articles | Metrics

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Resistance Switching of NiO-TiO2 Nano-Composite Thin Films LI Jian-chang， LI Run-xia， ZHENG Chen-ping 2016, 37 (5):  688-691.  DOI: 10.12068/j.issn.1005-3026.2016.05.017 Abstract ( 607 )   HTML   PDF (925KB) ( 741 )   The NiO-TiO2 (NTO) nanocomposite thin films with different n(Ni)/n(Ti) ratios were fabricated through sol-gel method. The current-voltage measurements indicated that the NTO films exhibit bipolar resistance switching behavior with low threshold voltage， high on/off ratio and long retention time. The low resistance state was governed by the Ohmic mechanism， while the high resistance state can be described with the oxygen-vacancy-related space charge limited conduction. The switching mechanism is related to the charge trapping/detrapping process. References | Related Articles | Metrics

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Numerical Study of Jet Impingement Cooling Process WANG Yu-yan， WANG Peng， BAI Mi-li， HU Cheng-zhi 2016, 37 (5):  692-696.  DOI: 10.12068/j.issn.1005-3026.2016.05.018 Abstract ( 1040 )   HTML   PDF (606KB) ( 1058 )   In the process of engine working， bottom injecting cooling can effectively reduce the piston temperature. Due to the complex flow field of jet impinging， an appropriate turbulence model and wall function must be utilized to describe the flow and heat transfer process. The κ-ε model (Standard， RNG and Realizable)， κ-ω model (Standard and SST) and low Reynolds number model (AB， AKN， CHC， YS， LB， LS and YS) were calculated and compared. The effects of the standard， scalable， non equilibrium and enhanced wall functions were analyzed for the wall region. Distribution law of the velocity and turbulent kinetic energy field were discussed， which are in accordance with the experiments. These results provide a basis for future numerical simulation of ejecting oil cooling at piston bottom. References | Related Articles | Metrics

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Scheduling Method for Multi-cluster Tools with Diverse Wafer Flow Patterns ZHOU Bing-hai， LI Ming 2016, 37 (5):  697-701.  DOI: 10.12068/j.issn.1005-3026.2016.05.019 Abstract ( 693 )   HTML   PDF (435KB) ( 747 )   To deal with scheduling problems of multi-cluster tools (MCTs) with different wafer types effectively， a scheduling algorithm considering diverse wafer flow patterns was put forward. Considered the wafer flow patterns， resource and residency constraints， mathematical programming models were set up with an objective of minimizing the Makespan. The scheduling problem of the single-armed MCTs was divided into two stages: determine the processing sequence of wafer lots and schedule the operating sequence of the robot arms. Applying ant colony search and bidirectional search strategies， ant system algorithm was introduced into the process of dynamic and adaptive time constraint set iterations. A new scheduling algroithm was built based on the ant systems and time (AS & TC). Simulation experiments results indicated that the algorithm is feasible. References | Related Articles | Metrics

Resources & Civil Engineering

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Simulation of Emission Limits for Paper-Making Industry Based on Petri Net and BAT JIANG Qiu-li， WANG Peng-fei， HAN Tian-fang， HU Xiao-min 2016, 37 (5):  702-706.  DOI: 10.12068/j.issn.1005-3026.2016.05.020 Abstract ( 600 )   HTML   PDF (355KB) ( 693 )   Through the simulation and calculation of object Petri net modeling and simulation environment (OPMSE) for the emission mass concentrations of COD， BOD5 and NH3-N in waste water from paper-making industry， the range of COD， BOD5 and NH3-N mass concentrations in typical paper-making industry were inquiried and investigated in Qinghe basin. The results show that when the confidence level is 99%， the confidence interval of COD is (34.09， 41.84)， the confidence interval of BOD5 is (6.65， 8.40)， and the confidence interval of NH3-N is (6.28， 7.34). The mass concentration of the optimum effluent is ρ(COD)=12. 79mg/L， ρ(BOD5)=2.62mg/L， ρ(NH3-N)=3. 33mg/L， while the mass concentrations of the worst effluent are ρ(COD)=70.47mg/L， ρ(BOD5)=14.51mg/L， ρ(NH3-N)=10.22mg/L. Then making a comparison between the emission standards and simulation results are got. The direct emission limits of the paper-making industry are ρ(COD)=45mg/L， ρ(BOD5)=9mg/L， ρ(NH3-N)=8mg/L. References | Related Articles | Metrics

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Isolation and Identification of an Efficient Bioflocculant-Producing Strain LIU Jin-liang， JIANG Bin-hui， ZHAO Xin， HU Xiao-min 2016, 37 (5):  706-710.  DOI: 10.12068/j.issn.1005-3026.2016.05.021 Abstract ( 666 )   HTML   PDF (805KB) ( 814 )   In order to ascertain taxonomic position of strain XHUA9， the polyphasic taxonomical identification was performed. The ferment products were separated and purified and then were analyzed by ultraviolet scanning spectrum (UV scanning spectrum) and infrared spectrum (IR spectrum). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain belonged to the genus Paenibacillus， sharing a most closely sequence similarity of 96.7% and DNA-DNA hybridization value of 51.6% with the type strain Paenibacillus hunanensis. The major polar lipids were diphosphatidylglycerol， phosphatidylglycerol， phosphatidylethanolamine and phosphatidylinositol. The predominant menaquinone is MK-7 and the major cellular fatty acids were anteiso-C15:0 and C16:0. The genomic DNA G+C content was 51.9 mol%. Based on the results of the present study， it is concluded that strain XHUA9 represents a novel species of the genus Paenibacillus， for which the name Paenibacillus shenyangensis sp. nov. is proposed. The UV scanning and IR spectra data showed that bioflocculant produced by strain XHUA9 was mainly composed of polysaccharides. References | Related Articles | Metrics

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Ball-Milling Micro-dissociation of Ironsand and Magnetic Force at Fine Level WANG Zhen-yang， ZHANG Jian-liang， LIU Zheng-jian， ZHANG Lu-ming 2016, 37 (5):  711-715.  DOI: 10.12068/j.issn.1005-3026.2016.05.022 Abstract ( 637 )   HTML   PDF (1006KB) ( 771 )   To broaden the iron ore sources and raise the grade of ironsand for long process ironmaking system， the ball-milling and magnetic separation were conducted on a ironsand from Indonesia. The analysis methods of X-ray diffraction (XRD)， scanning electron microscopy (SEM)， and laser particle size analyzer (LPSA) were used to investigate the micro-dissociation characteristics in different ball-milling stages， the influence of particle size and magnetic induction intensity on the concentrate grade and recovery and the force mechanism of fine ironsand in the process of magnetic separation. After the ball-milling to a certain stage， the granularity of ironsand is small and the locked mineral is in the form of inclusions which is hard to continue to disintegrate. Therefore， it makes little sense to reduce the ironsand granularity for the promotion of concentrate grade. In addition， when the ore is fine， water resistance will become the main force in the process of magnetic separation and the fine particles will not be able to reach the surface of the drum， and lead to a lower concentrate recovery rate. References | Related Articles | Metrics

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Effects of Coal Types on the Separation of Iron and Titanium in Titanomagnetite by Direct Reduction-Magnetic Separation GAO En-xia， SUN Ti-chang， YU Chun-xiao， LIU Zhi-guo 2016, 37 (5):  716-720.  DOI: 10.12068/j.issn.1005-3026.2016.05.023 Abstract ( 557 )   HTML   PDF (2432KB) ( 776 )   The influence of bitumite and anthracite on separation of Ti and Fe from beach titanomagnetite ore in the process of direct reduction-magnetic separation was investigated. The experimental results showed that the effects of bitumite and anthracite on iron reduction were similar during the range of experimental dosages. The reduction of titanomagnetite was insufficient when the coal dosages were not enough. With increasing dosages of coals， the quantity of reduced metallic iron increased in the roasted ore but the iron particles became smaller and were embeded closedly with other mineral particles， leading to low Fe grade， high TiO2 grade in the product. The metallic iron particles obtained by reduction roasting under the experimental conditions were pure. Compared with the same dosages of anthracite， the reducing atmosphere obtained by using bitumite with less content of fixed carbon was weaker but higher ash content of bitumite was good for the growth of metallic iron particles. Hence， the quantity of metallic iron was less but size of particle was larger in the roasted ore. So the direct-reduction iron(DRI) obtained by bitumite had higher Fe grade， lower iron recovery and lower TiO2 grade than that produced by anthracite. References | Related Articles | Metrics

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Safe Roof Blasting Thickness of VCR Stope Under Complex Boundary Condition WANG Wei， LUO Zhou-quan， QI Fei-xiang， CAO Sheng-xiang 2016, 37 (5):  721-725.  DOI: 10.12068/j.issn.1005-3026.2016.05.024 Abstract ( 559 )   HTML   PDF (467KB) ( 707 )   In order to determine safe roof blasting thickness of a VCR stope in Fankou mine， a mechanical ultimate-bearing analysis model of roof blasting under complex boundary condition (three sides fixed and one side supported) was constructed， the relationship between bearing capacity and roof blasting thickness was derived， and the minimum roof blasting thickness was calculated as 4. 6m. Accordingly， numerical simulations of blasting roof stability under various thicknesses were carried out to obtain the changing law between indexes (plastic zone volume， maximum vertical displacement and safety coefficient) and thickness. Research results show that safety indexes change obviously and plastic zone develops into complete connection when roof blasting thickness decreases from 5m to 4m， which proves the rationality of mechanical analysis. Referring to safety coefficient of similar mines， safe roof blasting thickness is revised as 6~7m. In practice， the fact that the blasting roof of 6. 5m thickness keeps safe all the time indicates that the results fit well with actual situation. References | Related Articles | Metrics

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Thermal Hazard Evaluation of Cyclohexanone Peroxide in Storage and Transport WEI Tong-tong， QIAN Xin-ming， YUAN Meng-qi 2016, 37 (5):  726-730.  DOI: 10.12068/j.issn.1005-3026.2016.05.025 Abstract ( 765 )   HTML   PDF (396KB) ( 827 )   The most serious thermal decomposition process of CYHPO (cyclohexanone peroxide) is investigated by accelerating rate calorimeter (ARC). The curves of thermal decomposition characteristic parameters versus time for the systems are obtained. The reaction kinetic parameters are calculated by the rate constant method. Modified by the thermal inertia factor， the temperature related parameters at the worst condition is obtained which can reflect the intrinsic thermal hazard of CYHPO. Based on reaction kinetic parameters and Semenov thermal explosion theory， the thermal hazard parameters such as TMRad， θNR， SADT， which are crucial in industry， are calculated. It is proved that the influence of instrumental error of ARC on the results can be neglected. The loading quality of CYHPO should not be exceeding 25kg and the optimal package is type K for this kind of package， the control temperature and emergency temperature should be lower than 59. 7℃. References | Related Articles | Metrics

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Models of Hyperelasticity with Softening and Simulation of Strain Localization for Brittle Granular Materials CHU Xi-hua， XIU Chen-xi， CHANG Jiang-fang 2016, 37 (5):  731-735.  DOI: 10.12068/j.issn.1005-3026.2016.05.026 Abstract ( 816 )   HTML   PDF (898KB) ( 1024 )   Two modified softening models are developed based on the Volokh softening model to consider the deformation and failure of granular material which is governed by shear deformation and failure. Different treatments to the volume strain energy and the shear strain energy are used in the two modified models， and a concept of the softening factor to indicate the degree of softening is proposed. Based on user-defined material (UMAT) of ABAQUS， the simulation is implemented. Numerical examples illustrated the capability and performance of the presented models in modeling strain localization and strain softening of granular materials. References | Related Articles | Metrics

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Centrifuge Model Test on the Seismic Response of Colluvial Landslide TU Jie-wen， LIU Hong-shuai， TANG Ai-ping， ZHENG Tong 2016, 37 (5):  736-740.  DOI: 10.12068/j.issn.1005-3026.2016.05.027 Abstract ( 612 )   HTML   PDF (2214KB) ( 808 )   Seismic response behaviors of colluvial landslide were discussed by inputting Taft wave with different intensities based on dynamic centrifuge model test. Results under Taft wave and Qingxi wave were comparatively analyzed. Results show that both the horizontal and vertical peak ground acceleration (PGA) amplification coefficients at slope surface increase with the increasing of height. The landslide shows an obvious altitude amplification effect. The distributions of horizontal PGA amplification coefficients in the landslide body are different from those of the landslide surface. The landslide surface has an obvious reflect effect on input seismic wave， and it shows the surface effect. The bedrock also has amplification effect along with the height of the landslide， and it has reductive effect compared with the input seismic waves. At the same height， the PGA amplification coefficients at landslide surface， landslide body and bedrock have different distributions with the increasing of earthquake amplitudes. References | Related Articles | Metrics

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Reinforcement Stability of Highways Resumption Embankment Geogrid CHU Fu-jiao， LIU Dun-wen， HOU Zhi-yong， YANG Wei 2016, 37 (5):  741-745.  DOI: 10.12068/j.issn.1005-3026.2016.05.028 Abstract ( 584 )   HTML   PDF (1060KB) ( 790 )   Because the new and old embankment were combined， there was uneven settlement and crack appeared on the road after reconstruction. According to the actual situation， embankment model was established by finite element analysis software midas GTS. The stress and displacement of the strengthened subgrade and the axial internal force of geogrid under different conditions were calculated. The calculation results indicated that the implanting geogrid in the resumption embankment had effect on the limiting of lateral displacement but little on the vertical settlement. When the step height of binding site was 1.5m， the lateral displacement and the shear stress of embankment slope were smaller. When 3-layer geogrid was added to upper of the combination embankment filling， the internal force tended to be stable. References | Related Articles | Metrics

Management Science

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Analysis of the Jump Dynamics of Stock Market Based on the Mixed GARCH Model GONG Xiao-li， ZHUANG Xin-tian， ZHANG Wei-ping 2016, 37 (5):  746-750.  DOI: 10.12068/j.issn.1005-3026.2016.05.029 Abstract ( 666 )   HTML   PDF (1352KB) ( 856 )   Based on the jump diffusion model， jump intensity is assumed to follow the self-threshold autoregressive model (SETAR) to reflect the structural break of jump density， and the GARCH model is used to describe the diffusion process of asset price volatility. The SETAR-GARCH model is constructed by making the jump density control probability of jump dynamics in which volatility affects jump density and by making the GARCH model control diffusion process in which jump dynamics influences volatility. Taking Shanghai real estate index for example， the empirical study finds that Shanghai real estate index exerts the threshold effect and significant GARCH effect， with 35. 21% jump mutation probability. The total variance of asset returns is largely caused by extreme jump dynamics. Investors’ evaluation of historical volatility directly affects jump intensity expectation， and the interference from historical jump dynamics has exacerbated the current volatility in the diffusion process， which illustrates that volatility diffusion processes and jump dynamics have a two-way feedback effect. References | Related Articles | Metrics

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Analysis of Formation of Social Endowment Insurance Based on the Multi-agent Model ZHAO Na， CHEN Kai 2016, 37 (5):  751-755.  DOI: 10.12068/j.issn.1005-3026.2016.05.030 Abstract ( 623 )   HTML   PDF (4686KB) ( 735 )   The mechanism formation of social endowment insurance was studied under the background that the government vigorously promotes the development of social endowment insurance system. By adopting the multi-agent method， a model containing government-agent， nursing-home-agent and family-agent was established based on the principle of utility maximizationin in order to simulate the formation of such a macro social economic phenomenon. The results showed that the employment rate and wage level are the main factors affecting the formation of social endowment insurance; the government subsidy impacts the effective demands of social endowment insignificantly， but has a significant impact on the service supply; the wealth level of the aged， the care degree for parents， the fund investment on the next generation and the care degree for the next generation do not have a remarkable effect on the formation of social endowment insurance. References | Related Articles | Metrics

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Emergency Resources Demand Forecast Based on FCM and CBR-GRA Dual Search DUAN Zai-peng， QIAN Xin-ming， XIA Deng-you， DUO Ying-quan 2016, 37 (5):  756-760.  DOI: 10.12068/j.issn.1005-3026.2016.05.031 Abstract ( 665 )   HTML   PDF (321KB) ( 444 )   Multi-data analysis and reasoning techniques were adopted to improve the forecasting speed and reliability of emergency resources demand. Firstly， based on the historical case information， the rescue case index weights were calculated. Then an algorithm combining fuzzy C-means clustering with case retrieval was established to increase the efficiency of case retrieval， which was performed by CBR (casebased reason) similarity and GRA (grey relational analysis) correlation. After the CBR similarity vector and GRA correlation vector were obtained， the grey relational analysis was used to calculate the similarity-correlation vector so as to ensure that similar cases are retrieved efficiently. Finally， a resources demand model was built up. The results confirmed that case clustering to achieve preliminary data filtering can enhance retrieval speed and combining two retrieval methods can improve the reliability of retrieval. References | Related Articles | Metrics