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15 August 2015, Volume 36 Issue 8 Previous Issue    Next Issue
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Information & Control

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A VWP-Section Fuzzy MPPT Method for PV Systems LI Shao-wu， GAO Xian-wen， FENG Yu-chang 2015, 36 (8):  1065-1069.  DOI: 10.12068/j.issn.1005-3026.2015.08.001 Abstract ( 564 )   HTML   PDF (476KB) ( 1025 )   It is difficult to simultaneously optimize the maximum power point tracking (MPPT) of the photovoltaic (PV) systems under the criteria of rapidity， accuracy and placidity， when the weather varies quickly. Aimed at solving this problem， a fuzzy MPPT method combined with variable weather parameters (VWP) is proposed. In this method， the power curve of the output signal is divided into three sections by the two VWP straight lines and each section has one fuzzy controller for tracking control. The overall control strategy is that a big tracking step-size is selected to ensure the MPPT rapidity when the control signal is far from its ideal value at maximum power point (MPP)， while a small tracking step-size is used to ensure the MPPT accuracy and placidity. Simulation experiments verify that the method proposed outperforms the conventional perturbation and observasion (P & O) method in rapidity， accuracy and placidity. References | Related Articles | Metrics

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Estimation of Boundary and Area Using Aircraft with Integrated Navigation and EKPF SHI Tian-wei， WANG Hong， SUN Ming-xing 2015, 36 (8):  1069-1073.  DOI: 10.12068/j.issn.1005-3026.2015.08.002 Abstract ( 619 )   HTML   PDF (867KB) ( 829 )   An algorithm was proposed to estimate the boundary and area of terrains with the quadrotor aircraft as the measuring instrument. The tightly coupled closed-loop integrated navigation system (strap-down inertial navigation system and global positioning system) was used to collect the positioning data. The Pauta criterion and EKPF (extended Kalman particle filter) were used to exclude the anomalous positioning data and dispose the remaining positioning data respectively. The boundary and area were estimated using the proposed algorithm based on the final positioning data. The front facing and bottom facing cameras of the aircraft were used to determine the flight direction and select the boundary points. This algorithm could be used to estimate irregular convex polygons， concave polygons and segmental arcs. The estimation error was limited within ±1.2%. The actual flight test results indicated the feasibility and accuracy of the proposed algorithm. References | Related Articles | Metrics

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Discrete Artificial Bee Colony Algorithm for TSP YU Hong-tao， GAO Li-qun， TIAN Wei-hua 2015, 36 (8):  1074-1079.  DOI: 10.12068/j.issn.1005-3026.2015.08.003 Abstract ( 1033 )   HTML   PDF (360KB) ( 1022 )   Aimed at traveling salesman problems， a novel discrete artificial bee colony algorithm is proposed. Based on the characteristics of such problems and discrete variables， the transforming mechanism and searching strategy of leader bees， follower bees and scout bees are redefined. The roles of bees are changed dynamically according to the values of profitability ratios. The 2-Opt operator and learning operator are used for leader bees to search the neighborhood of food sources so as to accelerate the convergence. A taboo list is introduced for follower bees to improve the algorithm’s intensification ability， and a repulsion operator is designed for scout bees to maintain the diversity of bee colonies. The proposed algorithm can strike a good balance between exploration and exploitation by using these operators. The simulation results show that it can improve the efficiency of solving traveling salesman problems by finding relatively satisfactory solutions in a short time. References | Related Articles | Metrics

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Magnetic Response Property of Magnetic Fluid Photonic Crystal Microcavity YING Yu， ZHAO Yong ， LYU Ri-qing， WU Di 2015, 36 (8):  1080-1083.  DOI: 10.12068/j.issn.1005-3026.2015.08.004 Abstract ( 507 )   HTML   PDF (681KB) ( 703 )   A kind of microcavity using magnetic fluid photonic crystal was presented， and its forming process was explained theoretically. Then the sensing property was studied， and the transmission characteristic was computed. The magnetic response properties of the proposed structure with the thickness of 6μm and 0.94μm were analyzed respectively. It was found that the central wavelength of resonance peak would be blue-shifted about 4.130μm and 0.076μm. The maximum sensitivity was 243nm/mT and 3.8nm/mT respectively. The sensor system exhibited the advantages of easy tuning， simple formation and high sensitivity， which would provide a new idea for optical sensor. References | Related Articles | Metrics

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A Soft Sensor Based on Optimized LSSVM for Elongation Prediction of Strip Steel WANG Chao， WANG Jian-hui， GU Shu-sheng， ZHANG Yu-xian 2015, 36 (8):  1084-1088.  DOI: 10.12068/j.issn.1005-3026.2015.08.005 Abstract ( 639 )   HTML   PDF (760KB) ( 592 )   The strip elongation is difficult to predict accurately with mathematical model， which related with multi-variable nonlinear factors and data noise in the annealing process. Thus， the optimal soft-sensing method was proposed based on kernel principal component analysis (KPCA) and optimized least squares support vector machine (LSSVM) by immune clone particle swarm optimization (ICPSO). ICPSO can avoid the particles sinking into premature convergence and running into local optimization in the iterative process which was generated by particle swarm optimization (PSO) algorithm， and can also optimize the parameters of LSSVM. Then， KPCA was used to denoise the input data set and capture the high-dimensional nonlinear principal components in input data space， and the principal components were input into the ICPSO-LSSVM model to establish the soft-sensing prediction model. The proposed method was successfully applied to the strip elongation prediction in annealing furnace. The simulation results show that the KPCA and ICPSO-LSSVM model have higher prediction accuracy， compared with other algorithms. References | Related Articles | Metrics

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Detection of Gross Error Using 3MAD-MMMD Based on Cluster Analysis XIAO Dong， BAO Jing-jing 2015, 36 (8):  1089-1092.  DOI: 10.12068/j.issn.1005-3026.2015.08.006 Abstract ( 677 )   HTML   PDF (344KB) ( 503 )   If there exist gross errors in the soft sensor modeling data， the accuracy of the model is largely affected. Therefore， for the data set to be used in the modeling process， a method of gross error detection of 3MAD-MMMD based on cluster analysis is proposed to process the data before modeling. The data of different variables in different time from the seamless pipe perforation process is collected. Then these data are arranged into a matrix. The 3MAD algorithm is used first to eliminate the large error of single-variables to get the new data matrix. Based on the Euclidean distance formula， the distance is then obtained from the data in matrix to another which is closest to it of the same variable. Finally， d○med， the median value of all variables’ closest distance， is treated as testing standards to detect gross error of new data matrix. It can be seen from the experimental and simulation results that the gross errors in the collected data sets are effectively eliminated in the 3MAD-MMMD detection method. References | Related Articles | Metrics

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Chaotic Optimization of Smith Predictor LI Qing-rui， LI Ping， ZHANG Peng 2015, 36 (8):  1093-1096.  DOI: 10.12068/j.issn.1005-3026.2015.08.007 Abstract ( 635 )   HTML   PDF (533KB) ( 526 )   A controller may be failure if the parameters of a Smith predictor are not precisely selected. Therefore， a method is proposed by which the parameters can be chaotically optimized on-line. The transfer function of the plant is identified first by chaotic mapping of the step response curve， then， the PID parameters are optimized off-line by using the identified model. When the model is changed， the parameters of the controller can be adjusted adaptively. The plant can be automatically identified， and rolling optimization process is performed in the method. The control system simulation for the plant is carried out， and the results show that the tracking performance and robustness of the controller are satisfactory. References | Related Articles | Metrics

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Pathology Simulation of Short QT Syndrome Based on an Improved Model of Ventricular Myocytes LIU Ji-hong ， LIN Yang， LIN Hai-ye 2015, 36 (8):  1097-1101.  DOI: 10.12068/j.issn.1005-3026.2015.08.008 Abstract ( 625 )   HTML   PDF (578KB) ( 496 )   Based on the data of the existing human ventricular cell model， a one-dimensional ventricular cell model is established. The pseudo ECG， action potentials for the endocardium cell， the mid-myocardium cell and the epicardium cell are simulated. The cycle simulation is carried out based on the established model， the parameters in the model are revised according to the problems encountered in the simulation process. It can be seen by comparing the existed experiment data with the simulation results that the improved model is reasonable and reliable. The KCNJ2-correlated short QT syndrome pathological conditions is also simulated by the improved model and the model proposed is validated. References | Related Articles | Metrics

Materials & Metallurgy

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Microstructure and Mechanical Behavior at High Strain Rates of As-extruded Mg-1.2Zn-0.8Y Alloy LI Hong-xiao， LI Cong， REN Yu-ping， QIN Gao-wu 2015, 36 (8):  1102-1106.  DOI: 10.12068/j.issn.1005-3026.2015.08.009 Abstract ( 556 )   HTML   PDF (731KB) ( 491 )   The structure of compounds and the microstructure of as-extruded Mg98Zn1.2Y0.8 alloy were investigated through OM， SEM， TEM and XRD. The dynamic behavior at high strain rate conditions of as-extruded Mg98Zn1.2Y0.8 alloy was also researched through the tensile test and fracture surface observation. The results show that the complete dynamic recrystallization occurs in the Mg98Zn1.2Y0.8 alloy during extruding process at a temperature of 300℃ and a reduction ratio of 16∶1. The fine particles of compound H-phase dispersively distribute in the Mg-based solid solution with fine grain size， and the particles of Z-phase mainly distribute along the grain boundaries. At room temperature， the yield strength and the tensile strength rise with the increase of strain rates from 100/s to 667/s， and the elongation also increases from 9.2% to 13%. Ductile fracture with some proportion of brittleness fracture occurs in the as-extruded Mg98Zn1.2Y0.8 alloy at room temperature and strain rate 100/s -667/s. References | Related Articles | Metrics

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Optimization of Adaptive Threading Strategy in Hot Strip Rolling JI Ya-feng， PENG Wen， MA Geng-sheng， ZHANG Dian-hua 2015, 36 (8):  1106-1109.  DOI: 10.12068/j.issn.1005-3026.2015.08.010 Abstract ( 538 )   HTML   PDF (395KB) ( 436 )   In the hot strip rolling process， the factors which affect the rolling force prediction need to be determined for the adaptive threading strategy. These factors were analyzed by calculating the influence coefficients， then linear equations were developed. The equations were solved by the least square method ，with the prediction deviations obtained. The adaptive threading schedule was verified by the test stand， which can ensure the schedule validity. The optimized strategy was successfully applied to a tandem hot mill. The application results show that the control precision of thickness is enhanced to a high level. References | Related Articles | Metrics

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Development of Hot-Stamping Steel with Large Product of Strength and Elongation Based on Dynamic Carbon Partitioning Mechanism PENG Liang-gui， LIU Wei-jie， LIU Xiang-hua， ZHI Ying 2015, 36 (8):  1110-1115.  DOI: 10.12068/j.issn.1005-3026.2015.08.011 Abstract ( 708 )   HTML   PDF (1028KB) ( 597 )   A low-carbon steel with Cu addition was heat-treated by direct quenching， Q&P (quenching and partitioning) and tempering processes. The mechanical properties and impact toughness of the test steel were investigated by universal testing machine and drop weight impact testing machine. The microstructure was characterized by SEM (scan electron microscope)， EPMA(electron probe microanalysis)， XRD (X-ray diffraction) and TEM (transmission electron microscope). The results show that the phenomenon of dynamic carbon partitioning from martensite to retained austenite in the continuous cooling process is observed and the impact toughness of test steel is improved by Q&P process and tempering process. The test steel has a good comprehensive mechanical properties: the product of tensile strength and elongation， the tensile strength， the total elongation and the impact toughness at room temperature are 20GPa%，1400MPa， 14% and 40J， respectively. The test steel based on dynamic carbon partitioning mechanism can meet the requirement of hot-stamping process and can be used as an excellent hot stamping steel with high product of strength and elongation. References | Related Articles | Metrics

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Application of Boron-bearing Iron Concentrate to Optimizing Sintering Quality of High Chromium Vanadium-Titanium Magnetite Ore FU Xiao-jiao， ZHAO Jia-qi， CHEN Shuang-yin， CHU Man-sheng 2015, 36 (8):  1115-1119.  DOI: 10.12068/j.issn.1005-3026.2015.08.012 Abstract ( 672 )   HTML   PDF (1126KB) ( 433 )   Experiment on the effects of boron-bearing iron concentrate applied to sintering of high chromium vanadium-titanium magnetic ore was carried out under laboratory conditions. The results show that， with the increase of boron-bearing iron concentrate addition， vertical sintering speed， sinter yield， tumbler strength， utilization coefficient raise at first then decrease， as well as composite indicator and RDI+3.15. When boron-bearing iron concentrate addition is 5.0%， the maximum values of the above indexes are 28.84mm·min-1， 86.02%， 61.2%， 1.919t·(m2·h)-1， 363 and 90.76%， respectively. The properties of sinter ore with adding 5.0% boron-bearing iron concentrate ore are superior to the properties of sinter ore without boron-bearing concentrate. As a result， properties of high chromium vanadium-titanium magnetite sinter ore are optimized with adding balanced amount of boron-bearing iron concentrate， and can meet the higher requirements of blast furnace process. References | Related Articles | Metrics

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Metallurgical Characteristics of Swirling Flow Reactor Using Gravity Potential Energy of Hot Metal from Blast Furnace WANG Fang， WANG Qiang， LIU Zhong-qiu， LI Bao-kuan 2015, 36 (8):  1120-1125.  DOI: 10.12068/j.issn.1005-3026.2015.08.013 Abstract ( 563 )   HTML   PDF (1092KB) ( 459 )   The jet-flow of hot metal from the blast furnace has a certain initial kinetic energy. In addition， the tapping channel has a certain degree of slope. An innovative metallurgical reactor using the gravitational potential energy of the hot metal was proposed. On the basis of turbulent model and multiphase flow model， the fluid flow and the free-surface shape with VOF (volume of fluid) model in metallurgical reactor was numerically simulated， which was verified by the water model. The results show that the best swirling flow is formed in the bowl-shape reactor compared with other shapes. The curve of residence time distribution (RTD) obtained from experiment is in good agreement with the simulated result. The effect of swirling flow in bowl-shape reactor is greater than the others， which produces the most intensive and stable swirling flow. References | Related Articles | Metrics

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Supply-Demand Forecast of Byproduct Gas System and Optimized Allocation of Surplus Gas YANG Jing-hui， CAI Jiu-ju， LIU Jing-yu， SUN Wen-qiang 2015, 36 (8):  1125-1129.  DOI: 10.12068/j.issn.1005-3026.2015.08.014 Abstract ( 599 )   HTML   PDF (665KB) ( 449 )   According to the practical situation in steel enterprises， the production process is classified into normal and abnormal production. Forecasting models of the gas production /consumption were established. Causal analysis is used for normal production and heuristic demarcate methods matching with self-learning function are used for abnormal production. A gas-allocating model for buffer users was established by using a mathematical programming method. The model can guide the co-operation between gasholders and boilers， and thus reasonably allocate the remained gas and maximize the utilization of the gas according to the characteristics of buffer users. Finally， the model was applied to a steel company， and the results show that gas emission can be successfully eliminated， which achieves the energy-saving production target. References | Related Articles | Metrics

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Optimization of Heat Recovery of Sinter Ore with Heat-Collecting Hood of Circular Cooler TIAN Wan-yi， ZHANG Jia-yuan， DAI Chuan-de， WANG Jian-ping 2015, 36 (8):  1130-1135.  DOI: 10.12068/j.issn.1005-3026.2015.08.015 Abstract ( 651 )   HTML   PDF (590KB) ( 565 )   The effects of some factors， including bed voidage， particle size， bed thickness， temperature and velocity of inlet air and sinter temperature， on the average temperature of air in heat-collecting hood on circular cooler of sinters were analyzed by simulation. The curves and the corresponding functions which describe the relationship between the average temperature of air and the factors were obtained by fitting the simulation results. A semiempirical function was developed with the method of undetermined coefficients and the fitting functions. Using the semiempirical function， the temperature of air can be predicted with error less than 8% compared with the test results. The arrangement of the traditional heat collecting hood was analyzed with the semiempirical function. In order to decrease the energy loss and increase the efficiency of waste heat recovery of sinter， an optimized collecting hood arrangement was proposed. References | Related Articles | Metrics

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Numerical Simulation of Gas-Liquid Two-Phase Flow in Zinc Electrowinning ZHOU Ping， LI Hao-lan， WEI Wen-wu ， SU Yin-biao 2015, 36 (8):  1136-1140.  DOI: 10.12068/j.issn.1005-3026.2015.08.016 Abstract ( 614 )   HTML   PDF (722KB) ( 602 )   The gas-liquid two-phase flows in zinc electrolytic cells with single plate and multiple plates were respectively numerically simulated with the commercial software of FLUENT. Based on the mechanism of the generation and movement of oxygen bubbles， the rising velocity of a single bubble was calculated. The results indicate that the rising velocity is 0.017m/s. With the effect of bubbles from the anode， the electrolyte near the anode flows upward and oppositely flows downward near the cathodes， forming a large recirculation zone in the cell. The average velocity of bubble cluster is 0.021m/s， which is consistent with the experimental data from the literature. In practical operation， with the joint action of the differential pressure and the bubble drag force， the recirculation of electrolyte flow can be enhanced remarkably. The average velocity of interelectrode fluid is 1.5 times higher than that under the bubble-free condition. This phenomenon indicates that the bubble movement can promote the refreshing of zinc electrolyte and restrain the dilution of zinc ions. References | Related Articles | Metrics

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Synthesis of NiFe2O4 Nanopowder by Low-Temperature Solid-State Reaction and Its Mechanism ZHANG Zhi-gang， LIU Yi-han， LUO Hong-jie， YAO Guang-chun 2015, 36 (8):  1141-1145.  DOI: 10.12068/j.issn.1005-3026.2015.08.017 Abstract ( 612 )   HTML   PDF (663KB) ( 492 )   The precursors ground by planetary ball milling at room temperature were calcined to obtain NiFe2O4 nanopowder. The effect of calcination temperature on the particle phase and morphology and the mechanisms of solid-state reaction were studied in detail. The results show that the activation energy of grain growth during calcination process is 12.08kJ·mol-1， indicating that the predominant mass transport mechanism is interfacial diffusion. The particles calcined at 700℃ showed strong agglomeration and low crystallinity with flaky amorphous compounds. The NiFe2O4 nanopowder calcined at 750℃ for 1h is of single phase with a particle size range of 35-85nm. The grains grew obviously when the calcination temperature increased to over 800℃. The main compositions of the precursor are Fe2O3， NiO and NiFe2O4. The low crystallinity of reaction products indicates the solid state reaction is not complete. The existence of salt particles can suppress grain growth， and thus decrease the particle size. References | Related Articles | Metrics

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Synthesis and Property of Side-Chain Liquid Crystalline Polymer Grafted Carbon Nanotubes XU Xin-yu， ZHAI Yu-chun 2015, 36 (8):  1146-1150.  DOI: 10.12068/j.issn.1005-3026.2015.08.018 Abstract ( 586 )   HTML   PDF (784KB) ( 435 )   A side-chain liquid crystal 4-allyloxybenzoyl-4’-hydroxyl-p-biphenyl ester (M) was synthesized using an in-situ polymerization method. Then we grafted different amounts of carbon nanotubes (CNTs) onto it. A series of liquid crystalline polymers generated liquid crystal composite materials because of polymerization reaction. The liquid crystalline composites were characterized by polarized optical microscopy， scanning electron microscopy and differential scanning calorimetry (DSC). The results show that a little CNTs are well dispersed in the liquid crystalline composites matrix， and they cannot change the texture of the original polymer. The DSC results show that the clear point and mesomorphic temperature range increase with the adding of CNTs. References | Related Articles | Metrics

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Synthesis and Properties of Liquid Crystal Elastomers Containing Fluorine and Chiral Crosslinking Agent HE Xiao-zhi， YU Fei-fei， SONG Zi-yan， HU Jian-she 2015, 36 (8):  1150-1154.  DOI: 10.12068/j.issn.1005-3026.2015.08.019 Abstract ( 727 )   HTML   PDF (623KB) ( 523 )   Nematic monomer: 4-(4-(allyloxy)benzoyloxy)phenyl 4-fluorobenzoate (M1) and non-liquid crystalline crosslinking agent: bis((4-(4-allyloxy)benzoyloxy)isosorbide benzoate)(MC) were synthesized. M1 and MC with different proportions reacted with polymethylhydrosiloxane and chiral liquid crystalline elastomers containing fluorine PI-PVIII were got. The chemical structures and mesomorphic properties of monomers and elastomers were studied by means of FT-IR， 1H NMR， POM， DSC， TGA and X-ray. The experiment results showed that short-hard liquid crystal elements containing fluorine could be induced into cholesteric phase with wonderful properties. PI presented nematic phase and PII-PVII displayed cholesteric phase with oily-streak and Grandjean texture. PVIII did not have any liquid crystalline properties. The glass-transition temperature increased first and then decreased， whereas both the melting point and clearing point decreased. The synthesized liquid crystal elastomers had good thermal stability， and the thermal weight loss temperature was greater than 300℃ with only 5% weight lost. References | Related Articles | Metrics

Mechanical Engineering

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FEM-based Frequency Reliability Analysis of Spindle System of CNC Lathes ZHANG Yi-min， WANG Hao， CAO Hui， YANG Zhou 2015, 36 (8):  1155-1159.  DOI: 10.12068/j.issn.1005-3026.2015.08.020 Abstract ( 634 )   HTML   PDF (481KB) ( 475 )   Based on the finite element method， we created a parametric three-dimension finite element model for spindle system and simplified the bearing as elastic support. Taken pulley and chuck into consideration， modal analysis of the entire system was conducted， thus the natural frequencies of the first eight vibrations and the corresponding spindle vibration modes were acquired. Critical speed of rotation was analyzed. We compared the working speed with rotation speed of the lowest non-zero set of frequency， hereby the rationality of design was verified. The ISIGHT integrated with ANSYS was used in designing orthogonal experiment and in calculating the lowest non-zero set of frequency. Diameters and length with tolerance requirements， and basic physical parameters considered as random variables， the BP neural network fitting method was used to get the relationship between the lowest non-zero set of frequency and random variables. The first order second moment (FOSM) method was used to calculate the spindle system reliability with specific rotation speed and reliability sensitivity of random variables. References | Related Articles | Metrics

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Evaluation of Correlation Dimensions of Engine Cylinder-Piston Clearance and Vibration Signal GUO Li-xin， LI Zheng-shou 2015, 36 (8):  1160-1163.  DOI: 10.12068/j.issn.1005-3026.2015.08.021 Abstract ( 480 )   HTML   PDF (595KB) ( 553 )   In order to evaluate the wear status of cylinder liner-piston components by using engine cylinder liners’ vibration signal features， this study established a dynamic model of cylinder liner， piston， crank and connecting rod of the engine and carried out its dynamic simulation. Then the vibration analysis of the cylinder liner surfaces was conducted， and the correlation dimension-based signal features of the simulated vibration signals were evaluated. The analytical results showed that when the cylinder-piston wear clearance increases， the vibration signal amplitude increases， the self-correlation degree also increases， and the correlation dimension of the cylinder liner surfaces’ vibration signal decreases. These correlation dimensions can serve as feature indexes to evaluate the wear status of engine cylinder liner-piston components. References | Related Articles | Metrics

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Cell-based Stochastic Smoothed Finite Element Method Based on the Orthogonal Expansion Theory of Random Field ZHOU Li-ming ， MENG Guang-wei， LI Feng， GUO Xue-dong 2015, 36 (8):  1164-1169.  DOI: 10.12068/j.issn.1005-3026.2015.08.022 Abstract ( 637 )   HTML   PDF (534KB) ( 460 )   To solve the stochastic parameter variation problem in engineering structures， the cell-based stochastic smoothed finite element method was proposed based on the orthogonal expansion theory. In the method， the Karhunen-Loève series orthogonally decompose the random field into independent random variables and the chaotic polynomial expands the random displacement response， and then the expended random field and displacement response are introduced into the cell-based stochastic smoothed finite element. The equilibrium equation of the proposed method is derived， and the computational formulas of the covariance matrix and the mean structural displacement are given. The numerical calculation indicates that the method has low meshing requirements and high precision. The random response of the square plate with a hole which has random material characteristics was further analyzed. The numerical results show that the proposed method is correct and feasible. References | Related Articles | Metrics

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Analysis of Flow Forces During Muti-valve’s Opening Under Excavator Virtual Load WANG An-lin， WANG Jian， FU Zhi-yi 2015, 36 (8):  1170-1174.  DOI: 10.12068/j.issn.1005-3026.2015.08.023 Abstract ( 537 )   HTML   PDF (824KB) ( 400 )   To improve the muti-valve’s commutation ability and to reduce the valve’s flow forces during its opening， the valve structure of a hydraulic excavator under virtual loads was designed. First， the excavator virtual load model was established based on the excavator dynamic test data， and the statistics were used to express the load’s periodic and random characteristics. Then， a 3D valve model with the boundary conditions of virtual load was proposed to solve the flow forces during the valve’s opening using the fluid structure interaction method. Finally， the flow force response characteristics of different valve spool structures were presented by the model. The results show that the spool with U-groove of moderate equivalent valve orifice area can effectively reduce the flow force under a series of virtual loads. References | Related Articles | Metrics

Resources & Civil Engineering

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Experimental Study on Mining Drift Position of Induced Caving Method for Steeply Inclined Fractured Orebody with Medium Thickness MA Jiao-yang， REN Feng-yu， CAO Jian-li， YAN Xi-ming 2015, 36 (8):  1175-1179.  DOI: 10.12068/j.issn.1005-3026.2015.08.024 Abstract ( 572 )   HTML   PDF (428KB) ( 550 )   Focusing on the mining of steeply inclined fractured orebody with medium thickness， based on the induced caving method using the following-vein drift， the relationship between the following-vein mining drift position and the dip angle of orebody was studied through physical simulation experiment combined with comprehensive analysis with recovery and dilution ratios as the quantitative and economic indices. The results are as follows: the recovery index is better when the following-vein drifts of both the upper and lower section are in the best position; the ratio of the distance from drift to footwall to the thickness of orebody has a different impact on the recovery and dilution ratios at the different dip angle of orebody; the best mining drift position gradually moves towards the footwall of orebody with the decrease of the dip angle of orebody; the scheme proposed is not applicable when the dip angle of orebody is less than 75°. According to the experimental results and mining conditions， the optimum mining drift position is determined as reference for similar mines. References | Related Articles | Metrics

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Analysis of Mesozoic Faulted Basin in Heishui Town， Liaoning Province ZHANG Zhi-bin， GONG En-pu， ZHAO Ming-peng， WANG Hai-jiao 2015, 36 (8):  1179-1183.  DOI: 10.12068/j.issn.1005-3026.2015.08.025 Abstract ( 501 )   HTML   PDF (1140KB) ( 469 )   Based on a survey of Mesozoic sedimentary basin in Heishui Town， Jianping County， Chaoyang City， Liaoning Province， the intrusive and volcanic rocks with good peripheral exposure and fresh at the basin edge were sampled systematically， whose chronology was tested through zircon with (LA-ICP-MS) U-Pb isotopic method. It was concluded that the basin was based on the intrusive rocks which formed during the early Triassic to the late Jurassic， and the basin basement is composed of the volcanic rocks of Yixian Formation. Based on the sporopollen testing and sedimentary characteristics， it was found that the basin is composed of lower Jiufotang Formation， Fuxin Formation in lower Cretaceous and Sunjiawan Formation in upper Cretaceous. By combining the borehole data， an evolution model of the basin could be established. The faults at the northern edge of the basin are contemporaneous structure， and the base is a graben basin in the shape of dustpan. References | Related Articles | Metrics

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Reductive Leaching of High Iron Low-Grade Manganese Ore with Pre-processed Cornstalk FENG Ya-li， YI Ai-fei， LI Hao-ran， WANG Wei-da 2015, 36 (8):  1184-1188.  DOI: 10.12068/j.issn.1005-3026.2015.08.026 Abstract ( 696 )   HTML   PDF (803KB) ( 459 )   Utilizing cornstalk pre-processing with sulfuric acid， leaching experiments were carried out to dispose of manganese ore containing Mn of 9.63%. The effects of pre-process time， cornstalk dosage， pre-process temperature， concentration of sulfuric acid and leaching temperature on manganese dissolution were investigated. The results showed that in the condition of pre-process cornstalk with dilute acid at 80oC， 2.5g of cornstalk and concentration of H2SO4 1.2mol/L for 10minutes， leaching manganese using pre-processed cornstalk as a reductant for 90 minutes at 90℃ could dissolve 92% of the manganese， and less than 20% Fe was dissolved. The FTIR analysis results indicated that cornstalk pre-processed with acid could destroy the structure of lignin， which is beneficial to leaching. References | Related Articles | Metrics

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A Method of Identifying Structural Homogeneity of Rock Mass Based on Fracture Spacing SONG Sheng-yuan， WANG Qing， CHEN Jian-ping， LI Yan-yan 2015, 36 (8):  1188-1192.  DOI: 10.12068/j.issn.1005-3026.2015.08.027 Abstract ( 555 )   HTML   PDF (455KB) ( 429 )   Fracture spacing in different directions can not only reflect heterogeneity and anisotropy of rock mass， but also can reflect the spatial distribution characteristics of fracture， therefore， a method that demarcate structural homogeneity according to fracture spacing is proposed on the basis of random mathematics. The method is successfully applied to the analysis of structural homogeneity in an adit of Songta hydro-power station. It is proved that there exists the spatial effect when dividing the structural homogeneity by changing the space of the compared samples. Compared with the acoustic test curve of rock mass， it is shown that the division of structural homogeneity with the spatial effect considered is consistent with the on-site situation. References | Related Articles | Metrics

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Calculation and Analysis of Original Dynamic Shear Modulus and Function of Soft Clay LUO Jun-hui， MIAO Lin-chang， SHI Wen-bo 2015, 36 (8):  1193-1198.  DOI: 10.12068/j.issn.1005-3026.2015.08.028 Abstract ( 633 )   HTML   PDF (685KB) ( 543 )   To research soft clay softening induced by moving metros load， an indoor GDS dynamic triaxial test on Nanjing soft clay was carried out. The computational formula with the original dynamic shear modulus was used to calculate and analyze the Nanjing soft clay. And an empirical formula considering the frequency factor was established. Meanwhile， a function considering the vibration number for the dynamic shear modulus was presented to calculate and analyze the Nanjing soft clay and the applicability was verified by testing on clay from different regions. It is shown that the original dynamic shear modulus formula considering the frequency factor can be accurately determined and the dynamic shear modulus function considering the vibration number has a good applicability to the clay from different regions. References | Related Articles | Metrics

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Distribution Characteristics and Ecological Risk of PAHs in River Courses of Urban Old Industrial Relocation Areas: A Case Study of Weigong River in Shenyang City LI Ying-hua， LI Hai-bo， XU Xin-yang， GONG Xuan 2015, 36 (8):  1199-1203.  DOI: 10.12068/j.issn.1005-3026.2015.08.029 Abstract ( 508 )   HTML   PDF (348KB) ( 491 )   Aimed at the distribution characteristics and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the river of an urban relocation area， the 16 priority PAHs by the Chinese Ministry of Environmental Protection were quantitatively analyzed in the water and sediment of Weigong River of Shenyang City， China from October 2011 to September 2012. The spatial distributions of PAHs were revealed by seasonal sampling and along-the-river sampling， and the ecological risk of PAHs was preliminarily assessed with entropy evaluation. The results showed that the mean concentrations of total PAHs were 0.721μg·L-1 in the water and 3777.8ng·g-1 in the sediment. A positive correlation was found between the concentrations of TOC (total organic carbon) and PAHs in both water and sediment. As a whole， the potential risk of PAHs pollution in Weigong River could be categorized as low to moderate. However， naphthalene and anthracene might cause toxicity to the aquatic organisms at some sampling sites. References | Related Articles | Metrics

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Analysis of Shear Lag Effect of Steel and Concrete Composite Box Girders WANG Lian-guang， WAN Jiang 2015, 36 (8):  1204-1208.  DOI: 10.12068/j.issn.1005-3026.2015.08.030 Abstract ( 598 )   HTML   PDF (425KB) ( 440 )   Based on the basic principle of warping displacement function setting， a series of parabolic warping displacement functions that meet the basic warping mode of concrete composite box girders were selected for the proposed approach. The energy variation principle was applied to establish the governing differential equations and corresponding natural boundary conditions in consideration of the effect of shear lag. Then the analytical solutions to typical simply supported composite girders under mid-span concentrated load were derived. The static calculation examples verified the rationality and applicability of selecting quadratic parabolic warping displacement functions. Meanwhile， the measured results and the analytical solutions were compared with the finite element calculations so as to confirm the effectiveness of the approach. The calculation formula based on energy principle can meet the practical needs in engineering and the calculation is simple. References | Related Articles | Metrics

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Shenyang Commercial Housing Price Index Based on Hedonic Price Model ZHAO Liang 2015, 36 (8):  1208-1211.  DOI: 10.12068/j.issn.1005-3026.2015.08.031 Abstract ( 630 )   HTML   PDF (353KB) ( 561 )   To analyze Shenyang’s commercial housing market， Shenyang commercial housing price index was studied with hedonic price on the basis of the price index construction at home and abroad and the actual situation of Shenyang real estate market. Using 16 hedonic variables and adopting the semi-logarithm model， a hedonic price model of Shenyang commercial housing was built and tested， which confirmed 14 hedonic variables impacting Shenyang commercial housing price as well as their interrelationships. Based on the price index formula， the hedonic price indexes of Shenyang commercial housing from 2006 to 2013 were calculated and it was concluded that the growth rate of Shenyang commercial housing price has slowed down year after year. Finally， some reasonable proposals were made to tackle the problems which might occur in the future market. References | Related Articles | Metrics

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Innovation Diffusion Modeling Based on Scale-Free Networks HUANG Wei-qiang， YAO Shuang， ZHUANG Xin-tian， XIN Wei 2015, 36 (8):  1212-1216.  DOI: 10.12068/j.issn.1005-3026.2015.08.032 Abstract ( 538 )   HTML   PDF (323KB) ( 677 )   Considering the influence of local area networks on innovation adoption decision-making of consumers， an innovation diffusion model from the micro to the macro was constructed based on the scale-free potential adopter networks. On one hand， the constructed model relaxed Bass model’s unrealistic assumptions of the consumer networks; on the other hand， the model introduced an important parameter of the scale-free networks (degree distribution exponential) ， which helped to integrate the micro-adoption mechanisms and macro-diffusion data. With an advantage of differential equation modeling， the model’s application value was improved. A further simulation analysis of the model demonstrated that the more heterogeneous consumer networks’ node degrees and the less network average degrees are， the deeper and the faster innovation diffusion will be. References | Related Articles | Metrics