Archive

15 September 2013, Volume 34 Issue 9 Previous Issue    Next Issue
---
Information & Control
Materials & Metallurgy
Mechanical Engineering
Resources & Civil Engineering
Management Science


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Information & Control

Select

Chaos OppositionBased Learning Harmony Search Algorithm OUYANG Haibin， GAO Liqun， GUO Li， KONG Xiangyong 2013, 34 (9):  1217-1221.  DOI: - Abstract ( 470 )   HTML   PDF (352KB) ( 855 )   Harmony search (HS) algorithm is easily trapped into local optimal. To improve this shortcoming， chaos oppositionbased learning harmony search (COLHS) algorithm was proposed. Based on the thought of aggregation and divergence， preliminary judgments whether this algorithm was trapped into local optimal or backwater status were given， then according to the judge result， disturbance strategy was integrated with oppositionbased learning technology. The ergodicity of logistic chaos sequence and the space extensibility of oppositionbased learning were used. Besides， to balance aggregation and divergence， the history information of harmony memory was used to define the updating factor and the evolution factor， which were applied to dynamically adjust the pitch adjustment rate (PAR) and the bandwidth (BW). Numerical results demonstrated that the proposed algorithm is better than HS and the other eight kinds of improved HS algorithms that reported in recent literatures. References | Related Articles | Metrics

Select

Acoustic Location Algorithm in Gas Pipelines Based on the GRNN of LPV Model Approach WANG Lina， GAO Xianwen， LIU Tan 2013, 34 (9):  1222-1226.  DOI: - Abstract ( 446 )   HTML   PDF (450KB) ( 532 )   Due to the problems of leakage detection and location in gas pipelines as well as the measurement difficulties for the gas in pipelines， a gas pipeline linear parameter varying (LPV) model was established， and the generalized regression neural network (GRNN) was designed， which took the theoretic time difference as input model， and the location of different point in pipes as output. Acoustic identification method was used for gas pipeline leakage fault diagnosis and location. Simulation was carried out using field data， and the results showed that acoustic location algorithm research in gas pipelines based on the GRNN of LPV model approach is an effective method， which can make the predictive value accurately track real value. The experimental results can provide the reliable basis for the industrial application of gas pipeline leak detection and location. References | Related Articles | Metrics

Select

New Passive Transit Signal Priority Control Strategy for the Bus Vehicles at Urban Arteries LIN Yongjie， YANG Xianfeng， ZOU Nan， JIA Lei 2013, 34 (9):  1227-1231.  DOI: - Abstract ( 585 )   HTML   PDF (462KB) ( 677 )   A progression signal plan along multiintersections is required for bus vehicles. However， for the traditional progression approach which concentrates on passenger cars， buses may not catch up the preset green band due to bus dwelling time at stops. For addressing this issue， a passive transit signal control strategy was developed. Firstly， the traditional multiband control method was improved for arterial signal control by considering the initial queue and bus stops. And then， a multibusband control approach was proposed for arterial signal control optimization based on the characteristics of bus operations. Finally， an integrated model consisting of multiband and multibusband was developed to trade off the benefits of passengercar drivers and bus passengers. Taking the Jingshi Road in Jinan as an example， the microsimulation software VISSIM was employed as an unbiased tool for model evaluation and comparisons. Simulation results reveal that the proposed busband control and integrated model can significantly reduce the stop frequency of buses and the average delay per person at the arterial， compared with the traditional multiband model. References | Related Articles | Metrics

Select

Characteristics of Birth and Death Nodes with IPLevel Topology ZHAO Hai， LIU Yiwen， AI Jun， JIA Siyuan 2013, 34 (9):  1232-1235.  DOI: - Abstract ( 561 )   HTML   PDF (754KB) ( 598 )   Combining the theory and method of complex network， Internet IPlevel topology measured by CAIDA was used to study characteristics of birth and death nodes. Characteristics of birth and death nodes’ degree distribution and powerlaw distribution were obtained. In addition， statistic and evolution analysis of birth attachments were achieved. The results show that both birth and death nodes accord with powerlaw distribution approximately， and birth nodes do not tend to connect with birth nodes， but connect the nodes which have existed already in the network. The number of attachment is likely to be 1. Because birth attachments do not accord with preferential attachment， the theory of the rich becoming richer has little significance on dynamic topology and nodes with high degree do not bring great impact on birth nodes. Generating mechanism of attachment is obtained， and the number of attachments is stable and universal， which provides a valid basis for Internet modeling. References | Related Articles | Metrics

Select

Method of Similarity Calculation of Fuzzy Concepts ZHANG Lingyu， MA Zongmin 2013, 34 (9):  1236-1239.  DOI: - Abstract ( 658 )   HTML   PDF (407KB) ( 617 )   Due to the fuzzy information cannot be handled by the classical approaches for ontology mapping and similarity calculation， the similarities between fuzzy concepts cannot be computed as well. To this end， a new method for similarity calculation of fuzzy concepts was provided based on vector space model， called SimFCVSM(similarity of fuzzy concept based on vector space model). The fuzzy relationships in fuzzy ontologies were firstly used to generate vector space model(VSM). And then the fuzzy concepts were represented as vectors in the VSM. Finally，the similarities for fuzzy concept pairs were obtained by calculating vectors. Therefore， the proposed SimFCVSM method can be used to calculate the similarity between fuzzy concepts based on VSM， effectively. References | Related Articles | Metrics

Select

A Constructing Method of Regular Expression’s Smaller εNFA JING Maohua， YANG Yixian， YU Changyong， XIN Yang 2013, 34 (9):  1240-1243.  DOI: - Abstract ( 594 )   HTML   PDF (422KB) ( 764 )   Regular expression matching technology based on finite automaton(FA)has been widely used in the network and information field. A new method was proposed to construct the smaller nondeterministic FA(NFA) of regular expressions， namely， grouping regular expression based on closure(GREC). The GREC method was constructed based on the principle that all kinds of homomorphism computing of regular expression were closure and the hierarchy and recursiveness of closure operation were in regular set. The regular expression was cut into pieces， and then the NFA was constructed for each slice. Finally the stack to the restructuring of the NFA of each slice was used to obtain the final NFA. It can be concluded that NFA can be quickly constructed by the proposed GREC method， which has higher space efficiency compared with traditional Thompson structured approach when the regular expression is too complex in hierarchical structure or contains too many closure operations. References | Related Articles | Metrics

Materials & Metallurgy

Select

Hot Deformation Behavior and Microstructural Evolution of S38MnSiV Microalloyed Forging Steel ZHAO Yang， YUAN Xiaoyun， CHEN Liqing， LIU Xianghua 2013, 34 (9):  1244-1247.  DOI: - Abstract ( 602 )   HTML   PDF (1104KB) ( 641 )   By conducting singlepass compression test in MMS300 thermomechanical simulator and optical microstructural observation， the hot deformation behavior of S38MnSiV microalloyed forging steel was investigated at temperature of 1173~1423K and strain rate of 001~10s-1. The effect law of strain rate and deformation temperature on dynamic recrystallization(DRX)behavior and microstructural evolution was gained， and the activation energy and the constitutive equation were established for hot deformation according to hyperbolic sine method. The results show that DRX is easier to occur at higher deformation temperature and lower strain rate. With the process of DRX， the average austenite grain size decreases with the increasing strain. When steady state stress is achieved， the austenite grain size remains almost the same，independent of the strain. References | Related Articles | Metrics

Select

Prediction of the Grain Size and the Morphology Evolution of Alloys in Solidification Process ZHOU Zhimin， WANG Na， LI Yong， GUAN Shurong 2013, 34 (9):  1248-1251.  DOI: - Abstract ( 770 )   HTML   PDF (1528KB) ( 1190 )   A theoretical model on the grain size prediction was established according to the thermodynamics of the alloy solidification and consideration on the factors of the nucleation and grain growth. The grain size of the near liquidus semicontinuous casting 6061 aluminum alloy was calculated by using the model. The calculated results are well consistent with the experimental ones with the maximum error less than 7μm. Through the analysis of the growing disturbance along the normal direction to the liquidsolid interface during the solidification， a equation of the critical grain diameter corresponding to a certain wave number and the dominant wavelength surround the spherical grains were obtained. The spherical grain growth and its transformation conditions and mechanism of dendritic grains with specific type were well explained by these expressions， which is of great significance to the study on the formation and evolution of the grains with different morphologies， and to the prediction of microstructures and properties of semisolid alloy as well as the processing optimization. References | Related Articles | Metrics

Select

Water Pressure Control Technology and Application on Hot Strip Rolling Water Supply System LI Zhenlei， JIANG Lianyun， YUAN Guo， WANG Guodong 2013, 34 (9):  1252-1256.  DOI: - Abstract ( 482 )   HTML   PDF (1221KB) ( 656 )   Four bypass pipes were installed with the regulatory valves on each pipe in the ultra fast cooling(UFC)supply system of the hot strip rolling process. The series and parallel water pressure control methods were designed in order to improve water pressure control precision. A suitable control method that was used in UFC water pressure control was obtained by the comparison analysis. A research on the water pressure stability when the bypass valve broken down had been done in the design of the control system. The theoretical analysis and practical application results indicated that both the series and parallel control methods manage the water pressure within the ideal range when the set water pressure is 035MPa.When the set water pressure is 085MPa， the effect of the practical application of the parallel control method is good， because the parallel control method has significant effects on decreasing of the water flow impact on the plates of regulatory valves during the reduce procedure of the open degree and the water hammer phenomenon is also avoided. References | Related Articles | Metrics

Select

Effects of Time of Applying Rotating Electromagnetic Stirring on the Solidification Microstructure of GCr15 Bearing Steels ZHENG Jinxing， XU Xiujie， WANG Engang， HE Jicheng 2013, 34 (9):  1257-1260.  DOI: - Abstract ( 439 )   HTML   PDF (655KB) ( 695 )   The effects of the time of applying rotating electromagnetic stirring on the solidification microstructure of GCr15 bearing steels were investigated via graphite mold casting. The results showed that imposing rotating electromagnetic stirring at different periods during the solidification process of the molten steel significantly influences the solidification microstructure of the bearing steel ingots. The sooner rotating electromagnetic stirring is imposed， the larger magnetic Taylor number (the characteristic nondimensional parameter to describe the forced convection by the magnetic field) is. Accordingly， the electromagnetic force generates remarkably in the molten steel， which indicates that the fluid flow is strong enough for the columnarequiaxed transition (CET). The equiaxed crystal ratio of the ingot increased to 52% when the rotating electromagnetic stirring is imposed during the period of 0~05min after the accomplishment of pouring. Furthermore， the fluid flow generated by rotating electromagnetic stirring promotes the breaking， melting and drifting away of the dendrites in the solidification front. The fragments of the dendrites proliferated and were brought to the centre of the molten pool which became the heterogeneous nucleus under the strong fluid convection. The constitutional supercooling degree increases with the decrease of temperature gradient which consequently in favor of the promotion of CET. References | Related Articles | Metrics

Select

Research on the Occurrence Form of Sulfur in LF Refining Slag LYU Ningning， YU Jingkun， SU Chang， WANG Hongzhang 2013, 34 (9):  1261-1264.  DOI: - Abstract ( 474 )   HTML   PDF (818KB) ( 550 )   (CaOA12O3)slag and(CaOSiO2A12O3)slag were synthesized with CaO， SiO2 and A12O3 as main raw materials. The occurrence form of the sulfur in the slag under different cooling methods such as watercooling and furnacecooling was investigated. The results showed that 11CaO·7A12O3·CaS solid solution is the main occurrence form of sulfur in the CaOA12O3 slag with the substrate of 12CaO·7A12O3. However，in the CaOSiO2A12O3 slag， when the A12O3 content was low， sulfur existed in the form of CaS single phase in both water and furnace cooling processes， while the A12O3 content was high， sulfur existed in the form of CaS single phase when the slag was watercooled， while when the slag was furnace cooled， the sulfur existed in the form of 11CaO·7A12O3·CaS solid solution. The occurrence form of sulfur in LF refining slags can be controlled by changing the cooling method and the composition of the slag. References | Related Articles | Metrics

Select

Reversing Calculation of Interface Heat Flux for Strip Casting Though Dendrite Arm Spacing QIU Yiqing， CHEN Wei， LIU Xuekai 2013, 34 (9):  1265-1267.  DOI: - Abstract ( 391 )   HTML   PDF (382KB) ( 516 )   According to heatconduction differential equation， the mathematical expression， by which interfacial heat flux during twinroll strip casting can be calculated on the basis of secondary dendrite arm spacing， was derived. The numerical calculation was carried out though this mathematical expression， taking 1Cr18Ni9Ti stainless steel as an research calculated object. The results showed that the density of the interfacial heat flux decreases with the increase of the solidification time， the declining rate of interfacial heat flux is very fast near meniscus， while is slower in the position from nearer Kiss point. The calculated interfacial heat flux density is of the same order of magnitude as that of the experimental data in the literature. In addition， the further calculation indicated that twinroll strip casting is a subrapid solidification process， which conforms to the actual situation. References | Related Articles | Metrics

Select

Kinetics of Dehydrogenation in Molten Aluminum Using Proton Conductor Hydrogen Pump DING Yushi， LI Ying， HUANG Wenlong， DENG Wenzhuo 2013, 34 (9):  1268-1271.  DOI: - Abstract ( 491 )   HTML   PDF (671KB) ( 610 )   The aluminum liquid dehydrogenation test was carried out by the selfmade BaCe09Y01O3-α proton conductor electrochemical hydrogen pump. The dynamic procedure of the aluminum liquid dehydrogenation was researched though fitting analysis of variation curve between hydrogen content with time. The dehydrogenation experiment results showed that the hydrogen content (S) of the aluminum liquid decreased in the dehydrogenation process. The relation of dehydrogenation rate and hydrogen content in aluminum liquid was obtained， and the results indicated the dehydrogenation rate v was 000116mL/(100g·min) when the hydrogen content was more than 0246mL/100g in the dehydrogenation process. When hydrogen content was less than 0246mL/100g， the dehydrogenation rate decreased with the decrease of the hydrogen content， which was in the rage of 00120S-00022， where the chemical reaction was the rate determining step. Hydrogen pump dehydrogenation limit hydrogen content decreased with the increase of applied voltage， when the applied voltage was more than 20V， the aluminum liquid hydrogen content was lower than 0096mL/100g， which satisfied the requirement of high pure aluminum on hydrogen content. References | Related Articles | Metrics

Select

Experimental Studies on the Flame Front Instability Characteristics in Filtration Combustion XUE Zhijia， YU Qingbo， LIU Hui， SHI Junrui 2013, 34 (9):  1273-1276.  DOI: - Abstract ( 463 )   HTML   PDF (648KB) ( 691 )   The flame front instability characteristics of the combustion of the methane/air premixed gas in the porous media burner were investigated. The experiment results showed that in a particle bed with the ball diameter of 6mm， the flame front changes from the regular symmetrical flame to the inclined flame gradually and split into two areas finally in a given initial uneven preheated zone when the equivalent ratio is 041， and the flow velocity is 042m/s. When the particle bed was arranged， the balls were tamped down to decrease the uneven distribution of porosity. The initially uneven preheated areas in the even distribution of the porosity caused the flame propagated unstably and misfired in the end. Even though the given initial preheated area was even， the flame front was still somewhat unsymmetrical. The results showed that the uneven structure of the particle bed is the main reason that the flame front inclines in the filtration combustion and the initial uneven factor accelerates the instability of the flame propagation. References | Related Articles | Metrics

Select

Thermal Decomposition Characteristics of Limonite and Their Influences on the Sintering Process PAN Wen， WU Keng， WANG Wenze， ZHAO Yong 2013, 34 (9):  1277-1281.  DOI: - Abstract ( 1214 )   HTML   PDF (509KB) ( 1447 )   The thermal decomposition characteristics of FMGF were investigated by the thermolgravimetric analysis. The experimental investigation showed that the decomposition of crystal water in FMGF completed when the temperatures were in the range of 200~400℃， which improved the gas permeability of the sintering layers that the heat from upper layers transferred to the lower layers effectively. The crystal water was decomposed so that the effects of crystal water decomposition in the FMGF on the solid fuel consumption and energy balance were reduced. The conclusion made from the thermal decomposition analysis was verified by the sintering pot tests and industrial application， which indicated that the rate of finial products of the sintering was increased and the solid fuel consumption was reduced under high proportion of limonite through increasing the proportion of iron ore fines with low assimilative capacity to improve the gas permeability of the sintering layers and the heat transfer. References | Related Articles | Metrics

Select

Investigation of the Reduction Kinetics Process of Sinter Ore by Sectional Stepwise Method ZHAO Yong， WU Keng， PAN Wen， LIU Qihang 2013, 34 (9):  1282-1286.  DOI: - Abstract ( 555 )   HTML   PDF (2241KB) ( 1092 )   According to the reduction kinetics characteristics of industrial production of sinter， a new model concerned chemical reduction kinetics and molecular diffusion of the cubic particles in different states of reduction process was established on the basis of mass transfer of metallurgy transport principle and the basic principle of the chemical reduction. The sectional stepwise method was adopted to study the reaction kinetics of the sinter particles reduced by CO. Then the switch point of the different ratelimiting steps and the relevant kinetic parameters were obtained. Finally， the relationship between the kinetic parameters and temperature was determined. Moreover， the accuracy of distinguishing different ratelimiting steps of this model and its rationality was verified through the observation of the microstructure evolution during the reduction process of sinter ores. Therefore， the sectional stepwise method determined the switch point of different ratelimiting steps and the relevant kinetic parameters， which can be universally used in the investigations of dynamics of other reaction process. References | Related Articles | Metrics

Mechanical Engineering

Select

Meshing Characteristics Analysis of Spur Gear Pair Considering Modification Coefficient ZHANG Yimin， YANG Jian， HU Peng， WANG Quanbin 2013, 34 (9):  1287-1291.  DOI: - Abstract ( 706 )   HTML   PDF (1270KB) ( 721 )   Meshing characteristics of spur gear pair were researched using finite element method. Parametric finite element model of modified spur gear pair was built on the on the basis of APDL. Numerical simulation of gear meshing was performed via application of explicit dynamic software LSDYNA. Dynamic meshing characteristics caused by gear meshing such as dynamic contact force and dynamic transmission error(DTE)were obtained， and the effect of modification coefficient on dynamic meshing characteristics was studied. Static transmission error(STE)was compared with the aforementioned DTE. Finally the reasons for the difference between the DTE and STE were discussed. The results shown that under different modification coefficients， the meshing frequency is always the main frequency component. Other frequency components are affected by modification coefficient， and amplitude of the frequency component close to natural frequency is relatively larger. The STE is much different from the DTE on both time and frequency domains. References | Related Articles | Metrics

Select

Prediction of Tool Wear Based on Generalized Dimensions and Optimized BP Neural Network ZHANG Kaifeng， YUAN Huiqun， NIE Peng 2013, 34 (9):  1292-1295.  DOI: - Abstract ( 521 )   HTML   PDF (670KB) ( 620 )   Based on multifractal theory，the generalized fractal dimensions of acoustic emission(AE)signals during cutting process were calculated using improved boxcounting method.The generalized dimension spectrums of AE signals under different tool wear conditions were obtained，and the relationship between tool wear quantity and generalized dimensions was analyzed.Together with cutting process parameters， the generalized fractal dimensions were taken as the input vectors of BP neural network after normalization.The initial weight and bias values of BP neural network were optimized with genetic algorithm which was used to predict the tool wear quantity.The test results show that the method can be effectively used for the prediction of tool wear， and the mean prediction error is 001mm. References | Related Articles | Metrics

Select

Dynamic Similarity Design of Rolling Ball Bearing in BearingRotor System LUO Zhong， CHEN Xiaobing， YU Qingwen， ZHANG Haijun 2013, 34 (9):  1296-1299.  DOI: - Abstract ( 428 )   HTML   PDF (443KB) ( 1021 )   For bearing dynamic similarity design problem of bearingrotor system scale model， the dynamic similar criterion of rolling ball bearing was established on the basis of dimensional analysis and similarity π theorem. Similar relations of all dynamic parameters between the model and prototype were obtained. Based on stiffness calculation formula of rolling ball bearing， similar relations between stiffness and basic parameters were achieved. Meanwhile the contact total deformation and minimum oil film thickness were calculated and verified. The validity and practicability of the asestablished relations are illustrated in design of actual bearingrotor model through a design example. References | Related Articles | Metrics

Select

Contact Characteristics Analysis of Combination Frame of Forging Press Under Two Conditions MA Hui， NAI Haiqiang， SONG Rongze， TANG Yusheng 2013, 34 (9):  1300-1304.  DOI: - Abstract ( 512 )   HTML   PDF (1214KB) ( 543 )   Taking a forging press as research object，relationship between the magnitude of interference and preload was determined by method of interference fit based on the ANSYS software. By analyzing the gap coefficient， contact state， contact pressure， tensile stress of dangerous tension rod and bending deformation of column， the effects of preload and eccentricity on the contact characteristics of combination frame were analyzed for the upsetting(condition 1)and drawing out(condition 2)in processes of forging and pressing. The results show that the condition of drawing out is more dangerous than that of the upsetting，and the gap coefficient should meet the following criteria:the contact area between the top rail and column greater than 05 and the gap coefficient β≤23. The results may provide a theory basis for structure design of forging press. References | Related Articles | Metrics

Select

Scheduling Algorithm for DoubleCluster Tools of Wafer Fabrication System with Reentrant Constraints ZHOU Binghai， SHI Xiaoming 2013, 34 (9):  1305-1309.  DOI: - Abstract ( 494 )   HTML   PDF (696KB) ( 679 )   To effectively solve scheduling problems of multicluster tools of wafer fabrication system with reentrant constraints in running process， a scheduling algorithm was proposed. Firstly， the characteristics of reentrant constraints of doublecluster tools were analyzed. The problem domain of doublecluster tool scheduling was established and mathematical programming models were set up to minimize the system cycle time. The scheduling problems of the doublecluster tools were decomposed into scheduling problems of singlecluster tool using the decomposition policy. A novel enlighten algorithm of robotic sequence searching was presented. Finally， simulation experiments were carried out to evaluate the proposed algorithm. The results indicate that the proposed algorithm is valid. References | Related Articles | Metrics

Select

Research on Static Equilibrium Position of the Hpoint for Polyurethane Foam CarSeat LI Rui， GUO Lixin 2013, 34 (9):  1310-1313.  DOI: - Abstract ( 548 )   HTML   PDF (1400KB) ( 687 )   A simplified 2D model for system of passenger and carseat was created in order to study the Hpoint of polyurethane foam carseat， in which the interaction between human body and seat was treated as spring model with nonlinear and viscoelastic properties. The Matlab integrodifferentialalgebraic solver ode15s was used to solve equilibrium position of the passenger and carseat model. The results show that the harder the material is， the closer the static equilibrium position is to the initial position of human body before the foam compressed. The larger the K3 spring stiffness is， the final equilibrium position of the body is more close to the initial position. The more forward K3 is moving， the body will be more slip into the seat. If μ1， the coefficient of friction between human body and cushion， is too small， body tends to slip out of seat. References | Related Articles | Metrics

Select

Accurate Test of Natural Frequency of Constrained Thin Cylindrical Shell LI Hui， SUN Wei， ZHANG Yongfeng， HAN Qingkai 2013, 34 (9):  1314-1318.  DOI: - Abstract ( 556 )   HTML   PDF (627KB) ( 665 )   For better understanding its vibration behavior， inherent characteristics of constrained thin cylindrical shell were calculated by transfer matrix method and FE method，respectively. Factors affecting highprecision test of natural frequency and their solutions were analyzed. The methods of using the torque wrench to quantitatively determine the constraint boundary conditions and adopting reasonable excitation signal， additional window and average processing were chosen to improve the test accuracy. Furthermore， four types of excitation experimental systems including hammer，electromagnetic exciter， piezoelectric ceramic exciter and vibration shaker were set up to measure natural frequencies and key test steps were exhibited. The results show that base excitation produced by vibration shaker does not bring any additional mass and stiffness to thin cylindrical shell and is in good accord with its real stressconstraint state. Thus，the combination of vibration shaker for excitation source and laser Doppler vibrometer for response test has the highest test accuracy of natural frequencies. References | Related Articles | Metrics

Select

Molecular Dynamics Study of Crack Extension of Metal Film JIANG Wenquan， DU Guangyu， BA Dechun， ZHA Yingying 2013, 34 (9):  1319-1321.  DOI: - Abstract ( 634 )   HTML   PDF (744KB) ( 718 )   The microscopic mechanism of metal film crack extension under impact loading was investigated. Molecular dynamics method was adopted to simulate Cu metal film， and the system kinetic energy， stress， strain and microstructure charts were obtained with surface cracks under impact loading. When the system stress shifted from compressive stress to tensile stress， the atoms on the crack got large kinetic energy， and atoms on crack tips began to sputter， then vacancies appeared in the crystal lattice. When tensile stress reached 364385MPa， lattice vacancies extended to blunt cuts， and the crack grew. The results show that the change of the system energy and stress causes bluntcut damage to the microcrack tips， which is the main reason of metal film crack extension under high speed impact loading. References | Related Articles | Metrics

Resources & Civil Engineering

Select

Stability Evaluation and Parameter Optimization on the Fractured Rock Mass Around Underground Stope DONG Jinkui， FENG Xiating， ZHANG Xiwei， ZHANG Zhonghui 2013, 34 (9):  1322-1325.  DOI: - Abstract ( 567 )   HTML   PDF (724KB) ( 701 )   The stope stability analysis of test stope in the gently inclined ore body with medium thickness was carried out in the Jiaojia Gold Mine， Shandong Province. By means of the engineering geologic investigation and rock mechanics experiments at the -390m level， many mechanical indexes which reflect the quality of engineering rock mass were acquired. On the basis of the mass data analysis， applying of “Q” and “RMR” rock mass quality classification， rock mass rating model was established. According to the rock mass rating model， together the revised Mathews stability graph and the critical span design method， maximum exposed surface size of stope and maximum span were obtained. Through this great amount of analysis， it will guarantee the stability of stope when the span of stoping drift is less than 8m. The result was applied to the industry test， there the exposed surface size is designed as 75m×15m， and the insitu observation is used to monitor the mining process. The monitoring indicated that the caving and spalling of roof or sidewall do not occurred during the mining，and the stability of stoping drift is guaranteed. References | Related Articles | Metrics

Select

Mining Scheme Optimization and Slope Stability Analysis for Transition from OpenPit to Underground Mining LIU Jie， ZHAO Xingdong， LU Zengxiang 2013, 34 (9):  1327-1330.  DOI: - Abstract ( 552 )   HTML   PDF (1056KB) ( 722 )   Taking the transition from openpit to underground mining of Mengjiabao iron mine as engineering background according to the plastic zone connection， computation divergence and displacement discontinuity as instable criterion of landslide， the strength reduction method and FLAC3D were used to calculate slope safety factor， determine potential slip surface of the slope and analyze slope stability under the condition of static and dynamic underground mining disturbance. Depending on the slope failure law under the different mining depth， the mining scheme was optimized. The results shown that the slope safety factor without the mining disturbance is 194， meeting stability requirement. In process of underground mining using nonfloor pillar sublevel caving stoping， the thickness of covering layer must reach up to 25m. It plays an important role in absorbing stress， transferring stress and slowing the energy dissipation speed. References | Related Articles | Metrics

Select

Interactive Effect of Dolomite and Quartz on the Floatability of Magnesite in Sodium Oleate Flotation System YAO Jin， YIN Wanzhong， WANG Yulian， ZHANG Lili 2013, 34 (9):  1330-1333.  DOI: - Abstract ( 554 )   HTML   PDF (872KB) ( 660 )   In the floatation system with sodium oleate as collector， the floatability of magnesite， dolomite and quartz and the effects of regulators on floatabilitiy of those three minerals were studied. In addition，the influences of dolomite and quartz on the floatability of magnesite， the influence of dolomite on the floatability of quartz and the influence of dolomite on the floatability of the mixture of magnesite and quartz were researched， and their mechanisms were explored. The results show that taking sodium oleate as collector， the floatabilities of magnesite and dolomite are close，and sodium hexametaphosphate and sodium silicate can depress the floatability of magnesite and dolomite. Moreover， these three minerals have interactive effects each other. For example，adding dolomite or quartz can decline the magnesite recovery， and adding dolomite can improve the quartz recovery， which are basically caused by the dissolution of minerals and the coverage of minerals on each others. References | Related Articles | Metrics

Select

Influence of Ultrafine Comminution by HPGR on Separation of VTi Magnetite in Panxi LI Lixia， YUAN Zhitao， GUO Xiaofei， XIE Qichun 2013, 34 (9):  1335-1338.  DOI: - Abstract ( 543 )   HTML   PDF (617KB) ( 637 )   Experiments of ultrafine comminution by HPGR and separation on VTi magnetite in Panxi were done. When d80 of feeding is 155mm，the yield of -32mm for the roll grinding centre product is 9105%，the yield of -0074mm is 1529% and P80 of roll grinding products is reduced to 155mm. The effect of circulation technology of edge product and closedcircuit on the size characteristics of crushed product was very obvious. Separating tests were performed on -32mm Panxi VTi magnetite from ultrafine comminution by HPGR using process of parallel separation of Fe and Ti. The results show when grind fineness is -0074mm 45%， Fe grade of iron concentrate is 5505% and recovery is 7064% in iron separation flowsheet， while TiO2 grade of titanium concentrate is 4778% and recovery is 3516% in titanium separation flowsheet at -0074mm 80%. References | Related Articles | Metrics

Select

Passivation Performance of Sodium Sulfide on Heavy Metal Ions in Soil WEI Dezhou， LIU Wengang， MI Jinyue， GAO Shuling 2013, 34 (9):  1339-1342.  DOI: - Abstract ( 722 )   HTML   PDF (690KB) ( 699 )   Sodium sulfide was used as passivator to deal with artificial simulation heavy metal contaminated soil with Cu2+，Zn2+ and Cr3+. The results show that sodium sulfide has effective passivation ability to the three heavy metal ions， and more than 95% passivation rates can be acquired for every heavy metal ion. X ray diffraction analysis result reveals that passivation products which contain CuS， ZnS and Cr(OH)3 can be obtained when sodium sulfide react with heavy metal ions. Solution chemistry analysis result shows that sulfide precipitation can be generated by sulfur ion reacting with heavy metal ions，or hydroxide precipitation can be generated by hydroxyl ion generated from sulfur ion hydrolysis reacting with heavy metal ions，so heavy metal ions can be removed by sodium sulfide. References | Related Articles | Metrics

Select

Numerical Simulation of Air Core Forming Inside Hydrocyclones and Its Influencing Factors CUI Baoyu， WEI Dezhou， LI Mingyang， FENG Yuqing 2013, 34 (9):  1343-1346.  DOI: - Abstract ( 612 )   HTML   PDF (865KB) ( 891 )   Numerical simulation of air core formation inside hydrocyclones was carried out by using a commercial computational fluid dynamics(CFD)modeling software package ANSYS/Fluent based on the Reynolds stress model(RSM)for the turbulence calculation and volume of fluid(VOF)model for capturing the airliquid interface. The numerical simulation shown that the air core formed when the time was 07s，which was in good agreement with the physical experiment conducted at a similar condition. The air of the air core entered the hydrocyclone from the underflow outlet and exhausted from the overflow outlet. The largest swing of the air core occurred in the region close to the underflow area，and a protuberance resembling the Adam′s apple appeared when the air core entered the overflow pipe. Unnecessary energy was consumed， but no extra perturbation was brought into the flow field by air core. Under current design and operation conditions， the structural parameters such as overflow and underflow outlet diameter and cone angle have more significant effects on the air core diameter than the operational parameter like the feeding rate. References | Related Articles | Metrics

Select

EconomicEcological Integration Optimization of the Ultimate Boundary of Metal OpenPit Mine GU Xiaowei， XU Xiaochuan， WANG Qing， LIU Jianping 2013, 34 (9):  1347-1350.  DOI: - Abstract ( 535 )   HTML   PDF (455KB) ( 695 )   Based on the regular block grade model and surface model， cone exclusive method was used to obtain a sequence of “geologically optimum final pits” and “geologically optimum pushbacks”. The geologically optimum pushbacks were put into an asbuilt dynamic sequencing model with the maximum NPV as the target function， which found out the best way as the optimum mining scheme. Then the best mining path of every geologically optimum final pit was found out as the optimal mining scheme. According to production plan of every geologically optimum final pit， the final pit with the largest NPV was chosen as optimum final pit， the best mining path of which was further chosen as the optimal production design， realizing the simultaneous optimization of the final pit and production design. Based on the ecological footprint theory， the mine ecocost model was constructed. The mine ecocost was calculated combining with the boundary production plan， which was added to boundary to make the exogenous ecocost endogenous， achieving the economicecological optimization of mine project and design. Application showed that ecocost has significant effect on ultimate boundary and mine returning on investment. References | Related Articles | Metrics

Select

Biosorption Characteristics of Heavy Metal Zn2+ from Acid Mine Drainage by Immobilized Biological Activated Carbon LIN Hai， ZHOU Shanshan， DONG YingBo， XU Xiaofang 2013, 34 (9):  1352-1356.  DOI: - Abstract ( 450 )   HTML   PDF (930KB) ( 586 )   Taking the strains T1 (Cellulosimicrobium funkei) screened out as the research object， and the law of the adsorption with Zn2+of acid mine drainage (AMD) by the immobilized biological activated carbon (IBAC) technology was studied. The results indicated that the removal rate of Zn2+ reaches to 7518%and the water quality is improved， under the optimum running parameters of IBAC reactor for treating AMD with pH of 4 and initial concentration of Zn2+ of 10000mg/L， such as hydraulic loading rate of 019m3·(m2·h)-1， gaswater ration of 10∶1， and hydraulic retention time of 380h. Coexisting ions of Cu2+， Cd2+， Fe3+ and Ni2+ can reduce removal of Zn2+by IBAC. Scanning electron microscopy images showed that strain T1 cells are fibrousshape and attach and grow on the surface of the activated carbon particles， and cells volume expansion occurs after adsorption Zn2+. EDS analysis shown that the microorganism fixed in activated carbon particle surface adsorbs a large of Zn2+. Reaction kinetics studies shown that it is basically fit for firstorder kinetics model that the IBAC adsorbs Zn2+ in AMD. References | Related Articles | Metrics

Select

Thermal Stability of Polyphenylene Sulfide Filter Media Using Thermogravimetry CHANG Deqiang， LIU Jingxian， MAO Ning， CHEN Baozhi 2013, 34 (9):  1357-1360.  DOI: - Abstract ( 689 )   HTML   PDF (625KB) ( 553 )   To study the thermal stability of PPS(polyphenylene sulfide)filter media， thermal degradation kinetics behavior of two kinds of PPS filter media was analyzed by thermogravimetry. Thermal degradation activation energy of PPS filter media in N2 was obtained according to FlynnWallOzawa method， and thermal stability of PPS filter media was discussed. The results showed that the initial decomposition temperature and activation energy of N3 sample are both higher than those of B1 sample; at the heating rate of 5K/min，the initial weight loss temperature of N3 sample is 12℃ higher than that of B1 sample; during the whole heating process， the weight loss rate of N3 sample is 5240% which is smaller than that of B1(5367%); the average thermal degradation activation energy of N3 is 55kJ/mol，bigger than that of B1 sample. Consequently， the thermal stability of N3 sample is better than that of B1 sample， and kinetic analysis can be used as an important method to evaluate the thermal stability of filter media. References | Related Articles | Metrics

Select

Research on Mechanics Characteristics of Polygonal Line Tower CableStayed Bridge LI Yanfeng， LIANG Li， WANG Fuchun 2013, 34 (9):  1361-1364.  DOI: - Abstract ( 518 )   HTML   PDF (1659KB) ( 633 )   Based on a polygonal line tower cablestayed bridge in Shenyang， according to mechanics characteristics of concrete polygonal line tower，the mechanics characteristic were analyzed through numerical analysis on the tower anchorage area. The results show that main tower existes serious stress concentration. After setting stiffening rib， the stress concentration coefficient decreases，and the outofplane bending of the tower is eliminated. At the same time， the vertical tensile stress appeares. Therefore， the design should increase the stiffening rib size appropriately and strengthen the vertical steel and anticracking rebar. References | Related Articles | Metrics

Management Science

Select

Multiperiod Inventory Strategy of OneWay Substitution GAO Cong， GUAN Zhimin， WANG Ying 2013, 34 (9):  1365-1368.  DOI: - Abstract ( 485 )   HTML   PDF (320KB) ( 606 )   A multiproduct multiperiod inventory problem with downward substitution was addressed. According to character of oneway substitution between the products， a model about order for products to ensure service was proposed when an inventory manager should make order for these products. The simulation annealing algorithm embedded with a simulation procedure was developed to get the maximal levels of products. Taking advantage of the substitution， the reorder point can be lowered without reduction of service level. The lower reorder point means less average inventory and lower order frequency. While the reduction of reorder point influences some varying parameters， such as the service level requirement， ordering cost and holding cost. With increase of reorder cost or decrease of holding cost， inventory will replenish more products frequently， which means the mitigation of the positive effect of the substitution. References | Related Articles | Metrics