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15 November 2013, Volume 34 Issue 11 Previous Issue    Next Issue
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Information & Control

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Improved Ant Colony AlgorithmBased Path Planning for Mobile Robot〓 ZHANG Qi， MA Jiacheng， XIE Wei， MA Liyong 2013, 34 (11):  1521-1524.  DOI: 10.12068/j.issn.1005-3026.2013.11.001 Abstract ( 728 )   HTML   PDF (450KB) ( 1312 )   To solve the contradictory between the convergence speed and the local optimum in ant colony algorithm，an improved ant colony optimization algorithm(IACO) was proposed for path planning of mobile robot in the static environment. The locations of start and goal were utilized to build the environmental model based on the simplified visibility graph. In IACO， the local path information was integrated with the initialization of pheromone and the selected probabilities of the paths，resulting in improving the convergence speed and avoiding the premature phenomenon as far as possible. For overcoming the possible stagnation phenomenon， crossover operation is drawn into the proposed algorithm and the value of α，β and ρ were updated， which enhanced the capability of escaping stagnation phenomenon. The simulation results demonstrated that the search efficiency of optimum path and the overall performance of the proposed algorithm were improved to be better than that of standard ACO. References | Related Articles | Metrics

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Hybrid Modeling Method of Comprehensive Energy Consumption for Oil and Gas Production Process LIU Tan， GAO Xianwen， WANG Lina 2013, 34 (11):  1525-1528.  DOI: 10.12068/j.issn.1005-3026.2013.11.002 Abstract ( 564 )   HTML   PDF (436KB) ( 752 )   In order to accurately predict the energy consumption in the oil and gas production process， the primary energy consumption indicator was determined through the analysis of the oil and gas production process. A hybrid modeling method was proposed， in which the mechanism model was combined with LSSVM to predict the comprehensive energy consumption of oil and gas production process. Based on the analysis of the whole production process and the relationship between subprocesses， the mechanistic model of the energy consumption was established， and then LSSVM was applied to compensate the error which could not be described using the mechanism model. The simulation results showed that the energy consumption of oil and gas production process could be accurately predicted with the proposed method， and the performance was better than those of mechanistic model and the model established by LSSVM. It could be also concluded that the hybrid model has better stability and reliability. When the model was applied to the actual production process in some oil recovery operation area， satisfactory results could be received. References | Related Articles | Metrics

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Vector Field Texture Rending Algorithm Based on Mesh〓 WANG Chengen， LI Haijie 2013, 34 (11):  1529-1532.  DOI: 10.12068/j.issn.1005-3026.2013.11.003 Abstract ( 535 )   HTML   PDF (638KB) ( 594 )   Based on the quick point positioning of grid and color rendering method， a vector field visualization texture mapping algorithm was proposed. The repeat calculation of the streamline tracking was reduced and the speed was greatly improved， which made the realtime large data be effectively utilized and the various needs in the engineering be satisfied. The effect was particularly obvious in the 3D visualization process. Not only the structure and trends of the vector field could be displayed， but also the vector field size could be indicated by the color graphic. Meanwhile the force aspects could be highlighted more flexible through selfcontrolling the proportion. In addition， the practicality of the algorithm was proved by presentation of turbine disc′s temperature gradient field and connecting rod's displacement field. References | Related Articles | Metrics

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Pathology Analysis Simulation of Heart Failure Based on Ion Channels〓 LIU Jihong， LIN Haiye， CUI Yue 2013, 34 (11):  1533-1536.  DOI: 10.12068/j.issn.1005-3026.2013.11.004 Abstract ( 561 )   HTML   PDF (365KB) ( 918 )   Simulating cardiac electrophysiology activities through the computer can economically and safely develop the treatment medicine of heart disease. Based on the mathematical model of myocardial cell ion channels， a myocyte ion channels functional simulation platform was achieved， including action potentials for Purkinje fibres cell， the endocardium cell， the midmyocardium cell and the epicardium cell. Pathological conditions were also simulated on the four kinds of cells in the designed system. By analyzing the normal and pathological simulation results， it is showed that the simulation results are consistent with the actual experimental data. The simulation system is reliable. References | Related Articles | Metrics

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Reliability Evaluation of StochasticFlow Network Under both Time and Cost Constraints SUN Yanrui 2013, 34 (11):  1537-1541.  DOI: 10.12068/j.issn.1005-3026.2013.11.005 Abstract ( 598 )   HTML   PDF (359KB) ( 565 )   A simple method was proposed to generate all minimal system states fulfilling the demand， time， and budget constraints (all lower boundary points). Inclusionexclusion formula with the lower boundary points was discussed. There are many cancelling terms in the direct expansion of the probability of a union of events， so an algorithm was proposed to determine the canceling terms. All data were supposed to be transmitted through k disjoint minimal paths simultaneously. It was pointed out that if all the pairs of canceling terms that unions of r1 terms and r terms(1<r≤k) were found out， the canceling terms of other unions in inclusionexclusion formula could be determined. The reliability formula was greatly simplified by using the proposed algorithm. References | Related Articles | Metrics

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ETT Metric Routing Protocol Based on Location Prediction〓 SHA Yi， XU Shuang， SUN Xiaowei， ZHANG Zhiwei 2013, 34 (11):  1542-1545.  DOI: 10.12068/j.issn.1005-3026.2013.11.006 Abstract ( 532 )   HTML   PDF (278KB) ( 505 )   A routing algorithm (AODVLPETT ) which is based on the location prediction was presented. Route selection was made by calculating the ETX(expected transmission count) value and bandwidth of links between nodes in the communication range. The following node location was predicted using the grey prediction model.Whether or not to use the ETT(expected transmission time) routing metric depended on whether the distance between the adjacent nodes was less than the communication radius. The QualNet simulation results show that， compared with the AODV， the overall performance of the network was improved with the AODVLPETT， what′s more， the network throughput and packet delivery rate were also improved. In addition， the average endtoend delay and average jitter frequency were both reduced. References | Related Articles | Metrics

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FourRotor Aircraft′s Autonomous Navigation in Corridor Based on Vanish Point ZHAO Hai， SHAO Shiliang， LI Dazhou， WANG Jialiang 2013, 34 (11):  1546-1549.  DOI: 10.12068/j.issn.1005-3026.2013.11.007 Abstract ( 599 )   HTML   PDF (799KB) ( 623 )   Aiming at the phenomenon that the existed vanish point estimating methods are not suitable for the real engineering application， a new VQME algorithm to estimate vanish point was proposed. This algorithm was proved to be reasonable， robust and realtime and at last the feasibility was proved in engineering applications. At the same time aiming at the characteristic of fourrotor aircraft's under actuated and multicoupled， a cascade multivariate RBF neural network PID adaptive control method was proposed too. With this adaptive control method and the stratagem of making the vanish point as the target， the autonomous navigation in corridor was implemented. References | Related Articles | Metrics

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SAP System Migration Based on Complex Network Analysis〓 AI Jun， WANG Haiyan， ZHANG Xiaodong， CUI Chongyang 2013, 34 (11):  1550-1553.  DOI: 10.12068/j.issn.1005-3026.2013.11.008 Abstract ( 656 )   HTML   PDF (907KB) ( 516 )   Centrality measures and topology robustness analysis were exploited to research SAP system migration in an enterprise. A networkhardware upgrade plan was presented based on betweenness centrality and a metric to measure local topological robustness was devised. Via simulation and implementation， effectiveness of the proposed methods was confirmed. Result shows that application of complex network on realworld system analysis and design can improve the robustness and respond time of the SAP system. References | Related Articles | Metrics

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Dissection of the AverageCase Performance of MRU Cache Replacement Policy〓 LYU Mingsong， GUO Hao， GUAN Nan 2013, 34 (11):  1554-1557.  DOI: 10.12068/j.issn.1005-3026.2013.11.009 Abstract ( 926 )   HTML   PDF (246KB) ( 533 )   Cache is a processor feature that can greatly affect the performance of programs. The averagecase performance of most recently used(MRU) Cache replacement policy was studied. Research results showed that MRU outperforms LRU in some circumstances. By analyzing loop structures with sequential memory accesses， the condition for this phenomenon is given and formally proved. Extensive experiments were conducted on realtime timing analysis benchmarks for different Cache configurations， which shows that MRU outperforms LRU in lots of execution scenarios. Combining this result and recent results on the realtime performance of MRU replacement policy， it can be concluded that MRU has very high performance in both averagecase and realtime metrics. References | Related Articles | Metrics

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Outlier Detection for Batch Processes Based on Partial Robust MRegression JIA Runda， MAO Zhizhong 2013, 34 (11):  1558-1561.  DOI: 10.12068/j.issn.1005-3026.2013.11.010 Abstract ( 568 )   HTML   PDF (442KB) ( 819 )   Batch processes modeling， online monitoring with multivariate statistical analysis at the core have gradually became the research focus of process industry， however， the reliability of such methods would be affected by a large number of outliers in process data. Thus， an outlier detection method for batch processes based on partial robust Mregression was proposed to solve this issue. First， the robust prediction model was established based on maximum correntropy estimator. Then partial robust Mregression algorithm was utilized to calculate the model regression coefficients. Finally， Hampel identifier was used to analyze the final weights， and the outlier detection was fulfilled. The proposed outlier detection method was applied to a batch reaction process， and the experimental results indicated that effectiveness of the proposed method. References | Related Articles | Metrics

Materials & Metallurgy

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Effects of Intercritical Annealing on Microstructure and Mechanical Properties of Low Silicon TRIP Steel with Phosphorus Addition〓 CHEN Peng， XU Yunbo， SHEN Chunyu， WANG Guodong 2013, 34 (11):  1562-1565.  DOI: 10.12068/j.issn.1005-3026.2013.11.011 Abstract ( 576 )   HTML   PDF (1585KB) ( 620 )   The microstructure and mechanical properties for low silicon transformationinduced plasticity (TRIP) steels with phosphorus addition under different annealing conditions were investigated in laboratory. The addition of low price element phosphorus reduced the silicon content which improved surface qualityand solved galvanizing problem with lowercosts. The results showed that the tensile strength increased with the increase of the annealing time， the tendency of the amount of the retained austenite first increased and then decreased at both intercritical temperatures. The largest amount of the retained austenite was 22% at the constant temperature of 780℃ for 180s while 20% at the constant temperature of 800℃ for 90s. The steels had excellent mechanical properties with the product of the tensile strength and elongation of 22854MPa·% when annealing at constant temperature of 780℃ for 180s. No mechanical property loss were caused by the phosphorus addition and the mechanical properties of the low silicon TRIP steels were excellent. References | Related Articles | Metrics

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Effects of New Heat Treatment Process on Microstructure and Mechanical Properties of Low Carbon NbTi Microalloyed Steels XIA Wenzhen， ZHAO Xianming， ZHANG Xiaoming， WU Di 2013, 34 (11):  1566-1570.  DOI: 10.12068/j.issn.1005-3026.2013.11.012 Abstract ( 504 )   HTML   PDF (1506KB) ( 474 )   The test steels were quenched to room temperature using a new heat treatment process， and the effects of the reheating temperature and relaxationquenching process on microstructure and mechanical properties of low carbon NbTi microalloyed steels were investigated. The results showed that the number of precipitates decreased， while the mean size increased with the size distribution getting even nonuniform. The martensitic lath bundle size growed and the size of each martensitic lath decreased with the increase of the reheating temperature. Compared with the sample quenched directly， the number of precipitates in the sample reduced， which was reheated to 850℃ and then relaxed by slowly cooling to 700℃ before quenching. Its mean diameter increased and the size distribution was more uneven. When the sample was reheated to 900℃ and also relaxed by slowly cooling to 700℃ before quenching， (Nb， Ti)x(CN)y continued to precipitate on the surface of intrinsic granular precipitates. The best reheating temperature was 900℃. Moreover， the tensile strength of the sample which was aircooled about 20s increasesd 24MPa and reached its maximum value. References | Related Articles | Metrics

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Effects of the Ball Scribing on Magnetic Properties of High Permeability GrainOriented Silicon Steels〓 WANG Hao， LI Changsheng， CAI Ban， Nkwachukwa CHUKWUCHEKWA 2013, 34 (11):  1571-1574.  DOI: 10.12068/j.issn.1005-3026.2013.11.013 Abstract ( 632 )   HTML   PDF (1008KB) ( 615 )   The effects of the ball scribing on magnetic properties of high permeability grainoriented silicon steels， including the iron loss， coercive force， relative permeability， and Barkhausen noise were investigated. The results showed that the iron loss and coercive force of the high permeability grainoriented silicon steels apparently decreased 162% and 147% respectively after 8mm ball scribing and they both decreased with the decrease of the scribing spacing at the same magnetic flux density. At high flux densities， the permeability of the high permeability grainoriented steels apparently increased， and Barkhausen noise decreased after the ball scribing. After comparison and analysis 8mm is settled as the optimum scribing spacing. The effects of the domain refinement on high permeability grainoriented silicon steels were interpreted from the static domain observation and principles of domain refinement. References | Related Articles | Metrics

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Effects of the Cooling Mode on the Temperature Uniformity of Ultra Heavy Plate Quenching〓 FU Tianliang， LI Yong， WANG Kun， WANG Zhaodong 2013, 34 (11):  1575-1579.  DOI: 10.12068/j.issn.1005-3026.2013.11.014 Abstract ( 667 )   HTML   PDF (1226KB) ( 599 )   The tank immersion mode and ultra fast continuous cooling mode were adopted for ultra heavy steel plate quenching， through comparing the effects of sustainable cooling and intermittent cooling on the cooling rates of the centre and near surface part and the temperature uniformity along the thickness direction， centre heat conduction and surface heat transfer characteristic of the ultra heavy steel plate during quenching were illustrated. Based on this， optimal quenching schedule was constructed. The results showed that， compared with sustainable continuous quenching， intermittent continuous quenching not only kept the lower surface cooling rate， but also increased centre cooling rate， and the temperature uniformity along the thickness direction was improved remarkably. When the water cooling and air cooling time ratio was 1. 4， the optimization effects appeared obviously. References | Related Articles | Metrics

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High Temperature Hot Corrosion Behaviors of Directional Solidification NiBase Superalloy DZ792 and DZ729G〓 HUANG Shuo， WANG Lei， HUANG Yan， LI Juntao 2013, 34 (11):  1580-1584.  DOI: 10.12068/j.issn.1005-3026.2013.11.015 Abstract ( 543 )   HTML   PDF (1366KB) ( 555 )   The hot corrosion behaviors and mechanisms of DZ792 and DZ792G alloys at 900℃ through 75%Na2SO4+25% NaCl salt deposit were investigated. The results showed that the hot corrosion mechanisms of DZ792 and DZ792G alloys under 900℃ salt deposit were “acidicalkali dissolution/inter sulfideoxide”. During the hot corrosion testing between 70h and 150h， the corrosion mechanism of DZ792G alloy changed from alkali to acidic dissolution mechanism， finally resulting in the catastrophic corrosion for DZ792G alloy， the O2 in molten salt preferentially reacted with the outside Tirich layer at the surface of DZ792 alloy rather than that with inner Cr2O3 layer owing to the high Ti content of this alloy， thus， the mechanism of the hot corrosion changed from alkali to acidic dissolution with the TiO2 reacted with the molten salt consuming the O2. However， because the Ti content of DZ792 alloy was lower than that of DZ792G， the Tirich layer formed in the middle of the multilayered oxide， and the outer Tirich oxide formed stable spinel NiTiO3. The outer Cr2O3 rich oxide layer of the DZ792 reacted with the salt directly， therefore， the further corrosion of DZ792 alloy enable to be inhibited. References | Related Articles | Metrics

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Three Component Interaction Model for Predicting the Formation Enthalpy of Multicomponent Alloys ZHOU Zhimin， SUN Yanrui 2013, 34 (11):  1585-1587.  DOI: 10.12068/j.issn.1005-3026.2013.11.016 Abstract ( 610 )   HTML   PDF (449KB) ( 711 )   The changes of the formation enthalpy of the system were investigated when the properties of any one component of a binary subsystem were affected by the component out of the subsystem. It was found from the simulation of the formation enthalpies of ternary alloys that the changes of the electronegativity and the electron density of one component of the binary subsystem were proportional to the sum of the electronegativity of both in and out of the subsystem. This effect could simply be taken into account in the calculation which was equivalent to the effect on the volume of the component. When more components existed out of the subsystem， the total contribution of their electronegativity could be equivalent to one component. It is shown from the calculation of the formation enthalpy of ternary alloys that the predicting results considering the effects of the three components were better than that using geometrical model and consistent with the experimental results. The method has great significance to the study of the thermodynamic properties of multicomponent system. References | Related Articles | Metrics

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The Symmetic Fluid Flow in an Asymmetic TwoStrand Tundish〓 LEI Hong， BI Qian， LUO Zhiheng， ZHAO Yan 2013, 34 (11):  1589-1592.  DOI: 10.12068/j.issn.1005-3026.2013.11.017 Abstract ( 551 )   HTML   PDF (1394KB) ( 674 )   Mathematical simulations and water modeling experiments were applied to study the fluid flow in an asymmetric twostrand tundish under different flow controlling devices， and the optimized configuration was used in the industrial continuous caster. The experimental results showed that the negative dead volume fraction appeared if the classic combined method was applied to calculate the dead volume fraction for each strand， so the mean residence time was chosen as the key parameter. In the former tundish， the mean residence time at the strand near the ladle shroud was 194 seconds， the difference of the mean residence time between two strands was 97 seconds， and the difference of the temperature between two strands was 5℃. The asymmetric distribution of the flow rate of the molten steel was realized using the asymmetric rectangle turbulence inhibitor at the exit of it. Because of the asymmetry of the turbulence inhibitor， the flow rate of the molten steel was asymmetrical at the exit of the turbulence inhibitor. In the optimized tundish with asymmetric rectangle turbulence inhibitor and multihole baffle the mean residence time at the strand near the ladle shroud was 211 seconds， the difference of the mean residence time between two strands was 34 seconds， and the difference of the temperature between two strands was 3℃. References | Related Articles | Metrics

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Experimental Investigation on Laminar Flame Speeds of Premixed CH4/O2/CO2 Mixture〓 HU Xianzhong， YU Qingbo， QIN Qin， WANG Zexin 2013, 34 (11):  1593-1596.  DOI: 10.12068/j.issn.1005-3026.2013.11.018 Abstract ( 796 )   HTML   PDF (450KB) ( 1222 )   The laminar flame speeds of CH4/O2/CO2 mixtures in atmospheric conditions were measured using Bunsen method. The whole surface area methodology based on the images of flame was performed to obtain the laminar flame speeds of the Bunsen burner. The effect factors on laminar flame velocities of CH4/O2/CO2 mixtures were discussed， including equivalence ratios (08~12)， oxygen concentrations (25%~35%) and dilutions (N2， CO2). Results showed that the laminar flame speeds of the premixed oxymethane mixture reached a maximum at the stoichiometric ratio of 1 while gradually lowered on either side. The laminar flame speeds increased with the increase of the O2 concentration and there was a quadratic function relationship between the flame velocities and the concentration of the O2. Compared with N2， the high concentration of CO2 decreased the flame speeds and the measured flame speeds using CO2 as the oxidizer was about onefifth of that using N2 as the oxidizer. References | Related Articles | Metrics

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Optimized Fitting of the Thermodynamic Data of Iron Oxide Reduction Reactions Based on Lingo〓 ZHANG Wei， ZHANG Juhua， ZOU Zongshu， TANG Biao 2013, 34 (11):  1597-1600.  DOI: 10.12068/j.issn.1005-3026.2013.11.019 Abstract ( 576 )   HTML   PDF (534KB) ( 845 )   A thermodynamic calculation model for the iron oxide reduction reactions was established based on the most recognized thermodynamic data of the pure substances. According to the model calculation， scattered accurate thermodynamic data of the balance reduction potential and the standard Gibbs free energy of the iron oxide reduction reactions were obtained depending on temperatures. With the mathematical simulation software Lingo 11， sixteen equilibrium GT formulas of the iron oxide reductions were fitted under the thermodynamic constraint of the BaurGlaessner diagram. Eight enthalpy change data at 298K for the reactions were also given. Results show that the eutectoid temperatures of the iron oxides reduced by CO and H2 are both 576℃， and the corresponding equilibrium reduction potentials are 5070% and 7583%， respectively. The reducibility transition temperature of CO and H2 is 819℃. References | Related Articles | Metrics

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Comparison of the Effects of Different Additives on the Solid Phase Carbon Thermal Reduction of Ilmenite〓 LYU Xuewei， ZHANG Kai， HUANG Run， SONG Bing 2013, 34 (11):  1601-1605.  DOI: 10.12068/j.issn.1005-3026.2013.11.020 Abstract ( 552 )   HTML   PDF (778KB) ( 700 )   The effects of adding FeSi， Na2B4O7， Na2CO3 on the solid phase reduction behaviors of ilmenite were studied with the thermogravimetric analysis (TG). From the analysis of the TG， DTG and DSC curves， the results showed that the mass loss ratio of the mixture of the ilmemite and coke during the reduction decreased by adding FeSi， while increased by adding Na2CO3 or Na2B4O7. All the three additives reduced the temperature at which the maximum reaction rate was obtained. The maximum mass loss rates of the reduction process both were increased with the addition of Na2CO3 or Na2B4O7 for 013%/min and 018%/min respectively; while the maximum mass loss rate decreased with the addition of FeSi. The mechanism of intensifying reduction of ilmenite were analyzed. The heat generated by the reaction of Si with Fe increases the temperature of reaction system. The mass transfer of the reactant during the reduction prcess is improved with the addition of Na2B4O7 due to its low melting temperature point， while the gasification reaction of C can be enhanced with the addition of Na2CO3. References | Related Articles | Metrics

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Comparison of the Bioleaching and Chemical Leaching of Cobaltiferous Ores LIU Wei， YANG Hongying， LIU Yuanyuan， LUO Wenjie 2013, 34 (11):  1606-1609.  DOI: 10.12068/j.issn.1005-3026.2013.11.021 Abstract ( 581 )   HTML   PDF (502KB) ( 841 )   The cobaltiferous ores were studied by the process mineralogy for their main composition， ore particle size distribution， contents of primary elements and mineral dissemination characteristics. The results showed that the main content of the sulfide ores was carrollite that most of them were in monomer form， while a part of them were intergrowth with other ores. The copper ores were composed of chalcopyrite， bornite， chalcocite， covellite. The ferric sulfide is pyrite primarily. The cobaltiferous ores were comprised of 163% cobalt， 105% copper， 1500% sulfur and 124% iron. Shaking flask experiments were used to test the leaching efficiency of the cobaltiferous ores using ZY101 bacteria which was cultured with good anticobalt properties in the lab. The results showed that the cobalt bioleaching efficiency by bioleaching was 8571% which was 6326% higher than that by chemical leaching with high iron solution. So it was more suitable that recovery of cobalt by bioleaching than by chemical leaching， and ZY101 was favored for cobalt leaching because of its high leaching efficiency and cobalt tolerance. References | Related Articles | Metrics

Mechanical Engineering

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Reliability Sensitivity Analysis Method of Mechanical Parts Based on Gamma Process Strength Degradation LYU Hao， ZHANG Yimin， WANG Qianqian 2013, 34 (11):  1610-1613.  DOI: 10.12068/j.issn.1005-3026.2013.11.022 Abstract ( 642 )   HTML   PDF (421KB) ( 795 )   The uncertainty of the initial strength was described by a random variable， and the evolution process of the strength degradation was regarded as the Gamma process. Then the perturbation method， the fourth moment and Edgeworth series method were used to solve the problem of reliability calculation with random parameters of arbitrary distributions. Matrix differentialbased formulas for calculating the reliability sensitivity with respect to the mean and the variance of the random variables was derived based on the matrix differential method. The reliability analysis of the bolts was taken as an example to verify the proposed method. The results showed that the method can effectively solve the problem of the reliability sensitivity of mechanical parts with strength degradation. References | Related Articles | Metrics

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VerticalHorizontal Coupling Vibration Characteristics of Strip Mill Rolls Under the Variable Friction〓 HOU Dongxiao， PENG Rongrong， LIU Haoran 2013, 34 (11):  1615-1619.  DOI: 10.12068/j.issn.1005-3026.2013.11.023 Abstract ( 607 )   HTML   PDF (769KB) ( 688 )   A dynamic rolling force model with variable friction factor in vertical and horizontal directions were obtained using the Orowan deformation area force balance theory. Then， a verticalhorizontal coupling nonlinear vibration dynamic model of strip mill was established considering the effect of the structure vibration. The approximate solution was solved by the multiplescale method， and the amplitudefrequency equation was obtained. Based on the actual parameters of 1780 rolling mill， the characteristics of amplitudefrequency were analyzed under different nonlinear parameters. Finally， the bifurcation behaviors of the coupling system was analyzed by the singularity theory， and 6 group different transition sets and bifurcation diagrams in the 2 parameter planes of the coupling system were obtained， which provided theoretical guidance for the further suppression of mill roll system vibration. References | Related Articles | Metrics

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Dynamic Comfort Evaluation of HighSpeed Train Based on Annoyance Rate Model 〓 GUO Yunpeng， SONG Guiqiu 2013, 34 (11):  1620-1624.  DOI: 10.12068/j.issn.1005-3026.2013.11.024 Abstract ( 560 )   HTML   PDF (600KB) ( 823 )   The traditional ISO dynamic comfort evaluation could only measure the vibration comforts qualitatively and the comfort of the highspeed train when seat and body separated. A nonlinear human bodyseat coupled simulation model with seven degrees of freedom is established considering the annoyance rate， which subjects to irregular excitation of a railway with speed of 350km/h. The model is simulated by annoyce rate， and its result is compared with that of the ISO evaluation method. The result shows that the ride comfort evaluation based on the annoyance rate model can compensate the defects of the traditional method， and the result of the evaluation can be quantitative. References | Related Articles | Metrics

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Damage Mechanisms Research for the HighSpeed Railway Axle Steel 25CrMo4 During Hot Cross Wedge Rolling HUO Yuanming， WANG Baoyu， LIN Jianguo， ZHOU Jing 2013, 34 (11):  1625-1629.  DOI: 10.12068/j.issn.1005-3026.2013.11.025 Abstract ( 611 )   HTML   PDF (219KB) ( 510 )   The approximate analysis method is used to make clear the damage mechanisms during cross wedge rolling. Hot tension and compression of 25CrMo4 specimens were implemented under three temperatures (1040， 1100 and 1160℃) and two strain rates (10 and 100s-1) on thermalmechanical simulator. The true stressstrain curve and microstructure was obtained and compared under tension and compression condition. Some conclusions can be drawn: The recovery and recrystallization leads to the softening mechanism during compression， and the plastic damage leads to the softening mechanism during tension. Plastic damage undergoes three phases: nucleation， growth and coalescence， whose type involves grain boundary damage and inclusion damage. Streamline is some place where refined grain， grain boundary damage and inclusion damage are apt to take place. The inclusion damage consists of that at grain boundary and inside grain. The axial tension stress is the main damage in highspeed railway axle during cross wedge rolling. References | Related Articles | Metrics

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Study and Realization of Transition Motion from Biped Standing to Ladder Climbing for a Humanoid Robot〓 LU Zhiguo 2013, 34 (11):  1630-1633.  DOI: 10.12068/j.issn.1005-3026.2013.11.026 Abstract ( 515 )   HTML   PDF (970KB) ( 751 )   The transition motion from biped standing to ladder climbing was investigated with a humanoid robot under the changed environmental boundary condition. To improve the stability in the process of ladder climbing motion， the robot catches the rung firstly， and then adjusts the location of body with respect to the supporting foot based on the reaction forces between the rung and robot hands. Finally， the balance of robot body was maintained in the proposed transition motion. Experimental results prove that the proposed control strategy can prevent the falling accident， which may be caused by environmental parameter errors， external force disturbances， initial joint angle errors， and so on. It is effective to guarantee the transition motion of robot from biped standing to ladder climbing smoothly and successfully. References | Related Articles | Metrics

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Robot Simulation and RealTime Monitoring Based on Virtual Reality YANG Jianyu， XIE Hualong， HAN Xiufeng， WANG Wanshan 2013, 34 (11):  1634-1637.  DOI: 10.12068/j.issn.1005-3026.2013.11.027 Abstract ( 693 )   HTML   PDF (1440KB) ( 632 )   The discovery and try of combining operating simulation with real time monitoring and control together for a robot was studied. An experimental robot and two virtual robots were built for work simulation and real time monitoring， respectively. Together with the contribution of robot， microcontrollers and wireless communication modules， an experimental system was constructed to carry out several experiments， and methods for locating and controlling of the experimental robot were discussed as well. The results confirm that virtual reality technology can not only act as an effective auxiliary to video monitoring methods， but also bring more controlling experience in remote operation. Meanwhile， it offers better assistant effect with the same data transferring bandwidth compared to video feedback strategies. References | Related Articles | Metrics

Resources & Civil Engineering

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Numerical Simulation to Influence of Perforation Angle on Fracture Propagation Under Hydraulic Fracturing MEN Xiaoxi， TANG Chunan， HAN Zhihui， MA Tianhui 2013, 34 (11):  1638-1641.  DOI: 10.12068/j.issn.1005-3026.2013.11.028 Abstract ( 670 )   HTML   PDF (724KB) ( 673 )   Hydraulic fracturing process of the heterogeneity rockmass under different perforation angles was simulated using the RFPA2D20Flow. Considering the heterogeneous characteristics of rock in a mesoscale， a seepagestressfailure coupling model was created based on the finite element calculation method. The simulation results show that the maximum principal stress controls the fracture propagation direction no matter how perforation angle changes. With the increase of the perforation angle， a turning fracture becomes more obvious and the turning distance bigger. The best perforation angle area is from 0° to 30°. The numerically simulated results were in agreement with the experimental results. References | Related Articles | Metrics

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Study on Design and Optimization of Mining Sequence for Deep and Large Ore Body AN Long， XU Shuai， REN Shaofeng， ZHANG Xiongtian 2013, 34 (11):  1642-1646.  DOI: 10.12068/j.issn.1005-3026.2013.11.029 Abstract ( 495 )   HTML   PDF (2088KB) ( 700 )   The optimization sequence for the safe and effective mining of deep and largescale ore body under high stress environment was studied. Five mining sequences for room and four mining sequences for the pillar have been put forward according to a reasonable production capacity， technical and economic indicators， and are used for establishing the numerical models of FLAC3D . The results show that， among the five room mining sequences the optimal mining sequence is to extract ore rooms 1#， 5#， 9#， 16# and 12# and then followed by ore rooms 3#， 7#， 10#， 14# and 18#， where the stress concentration is the lowest and the displacement variation is smallest. The optimal mining sequence for the pillars is that the pillars 2#， 6#， 11#， 15# in panel mining are firstly extracted and then followed by pillars 4#， 8#， 13#， 17#， where the stress concentration is the lowest. To compare the regular pattern of stress release and the variation of displacement under different schemes， it is observed that after mining stopes of the panel， compressive stress concentration moves to the rib pillar of the central panel， which will be harmful to the roadway of rib pillars. Therefore， support in this area should be strengthened. References | Related Articles | Metrics

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Mechanism for Higher Iron Grade of Reverse Flotation Tailings of AnshanType Hematite Ore LI Lixia， ZHU Yulan， YUAN Zhitao， YAN Zan 2013, 34 (11):  1647-1650.  DOI: 10.12068/j.issn.1005-3026.2013.11.030 Abstract ( 553 )   HTML   PDF (725KB) ( 634 )   For the high iron grade in tailings of Anshantype hematite reverse flotation process， chemical element composition， phase composition， particle size distribution and mineral dissociation degree of samples collected from reverse flotation process were carried out by means of Xray diffraction analysis， chemical element analysis， granularity analysis and scanning electron microscope. The results show that some highly dissociated superfine iron minerals exist in scavenging tailings， which adsorb on some coarse gangue minerals to form “carrier flotation” and entered into tailings along with the carrier， and cause the higher iron grade of tailings. References | Related Articles | Metrics

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Phosphorus Occurrence State and Phosphorus Removal Research of a High Phosphorous Oolitic Hematite by Direct Reduction Roasting Method XU Yan， SUN Tichang， LIU Zhiguo， XU Chengyan 2013, 34 (11):  1651-1655.  DOI: 10.12068/j.issn.1005-3026.2013.11.031 Abstract ( 478 )   HTML   PDF (655KB) ( 713 )   The phosphorus occurrence states of high phosphorous oolitic hematite in Nigeria were studied by soak leaching and electrodialysis test. The characteristics of roasted products in the beneficiation by direct reduction roasting with dephosphorization agent Na2CO3 was also analyzed using the XRD and SEM. It showed that phosphorusbearing minerals mainly existed as crandallite (CaAl3(OH)6(HPO4)(PO4)) and vauxite (FeAl2(PO4)2OH·6H2O)， which embedded in the fissures and holes of oolitic iron ore particles， or existed as the form of isomorphism interfusing in the ore mechanically. Separation of phosphorus and iron can be realized by direct reduction roasting (adding dephosphorizing agent Na2CO3) and magnetic separation. Phosphorus can be removed in two ways: part of the phosphorus was separated with iron and existed in the gangue mineral，which could be removed by grinding and magnetic separation. The other part of the phosphorusbearing minerals was transferred into the soluble phosphorus by reacting with the dephosphorization agent Na2CO3. Then the phosphorus content of the reduced iron products was reduced. References | Related Articles | Metrics

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Earthquake Response Spectrum Analysis of Considering SoilStructure Interaction XU Yuan， CONG Long， HU Yingpeng， LIANG Yan 2013, 34 (11):  1656-1659.  DOI: 10.12068/j.issn.1005-3026.2013.11.032 Abstract ( 669 )   HTML   PDF (767KB) ( 797 )   The application of artificial boundary is a key issue in seismic analysis of the interaction system. The method that how to implement the viscous elastic boundary in SAP2000 was introduced and a framework module was set up and cycle variation of a series of different site soil considering soilstructure interaction was calculated. Besides， based on the design response spectra， total seismic force and maximum displacements of the upper structure were calculated， when considering the interaction or not. When the interaction was considered， especially the soft soil， the cycle of upper part， seismic force， maximum displacement of toplevel changed greatly. References | Related Articles | Metrics

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A New Method for Control the Random Seismic Response of Multistorey Building MA Yongquan， QIU Hongxing 2013, 34 (11):  1660-1664.  DOI: 10.12068/j.issn.1005-3026.2013.11.033 Abstract ( 370 )   HTML   PDF (488KB) ( 451 )   In order to reduce the seismic response of the multistorey reinforced concrete frame building structure， the nonlinear system motion equation which involved the contribution of the TMD and LRB is established. The equations which consist of nonclassical damping， asymmetry stiffness and mass are obtained by expanding the firstorder vibration mode of structure， and the equations are decoupled using the complex modal theory. The program is compiled for solving the problem how to acquire the analytical solutions of random seismic response of structure. The validity of this algorithm was verified by comparing with calculation results of deterministic algorithms. The consequences indicate that the TMD and LRB united control could decrease the seismic response of main structure more obviously than TMD control， for instance， displacement and acceleration. References | Related Articles | Metrics

Management Science

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Impact of Dynamic Inconsistency on Optimal LongTerm Contracts LU Yang， ZHUANG Xintian 2013, 34 (11):  1665-1668.  DOI: 10.12068/j.issn.1005-3026.2013.11.034 Abstract ( 534 )   HTML   PDF (321KB) ( 480 )   With the repeated moral hazard of longterm contracts aimed at and the agent of time preference taken into account， a threeperiod incentive model was developed and the impact of dynamic inconsistency on longterm contracts was then explored. The results showed that dynamic inconsistency does not change the memorability of longterm contracts， i. e. the high output at the current stage will positively affect the agent's payoff in the later periods; dynamic inconsistency does change the martingales of different periods， and the agent's optimal utility in Period 1 is less than the expected value in Period 2 and Period 3. References | Related Articles | Metrics

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Effects of Nontradable Shares Reform on the Structural Stability of China′s Stock CrossCorrelation Networks HUANG Weiqiang， YAO Shuang， ZHUANG Xintian 2013, 34 (11):  1669-1672.  DOI: 10.12068/j.issn.1005-3026.2013.11.035 Abstract ( 591 )   HTML   PDF (826KB) ( 469 )   By collecting the yield data of Shanghai and Shenzhen A shares from 2002 to 2012， this paper constructs the stock crosscorrelation networks of pre， in and postnontradable shares reform periods and empirically studies the networks' structural stability under perturbations. The results demonstrate that from the perspective of yield synchronization and maximal eigenvalue of correlation matrix， the networks' structural stability is not changed in the process of the nontradable shares reform， and is strengthened after this reform. Moreover， from the perspective of the networks' basic topological features， the reform does not significantly affect the stability of network average shortest path length and average clustering coefficient under perturbations. This study might provide guidance to portfolio investment and risk management in the stock markets. References | Related Articles | Metrics