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    Information & Control
    Multivariate Process Monitoring Based on the Characteristic Analysis of the Data
    ZHANG Shu-mei, WANG Fu-li, WANG Shu, LI Qiang-qiang
    2017, 38 (5):  609-614.  DOI: 10.12068/j.issn.1005-3026.2017.05.001
    Abstract ( 710 )   HTML   PDF (682KB) ( 996 )  

    Multivariate statistical process monitoring methods such as PCA and ICA are always based on a variety of assumptions. If the constraints of these methods have not been considered when selecting these methods, wrong conclusions will be obtained and the rate of high leaking and false alarm will be increased. To solve the constraints problem of these methods in application, a data characteristic analysis method was proposed to test the correlation of the variables automatically, in which parameter optimization was conducted and the set of linear variables was eliminated sequentially. The simulation illustrated that the proposed method can select appropriate modelling method automatically according to data characteristics and applicable conditions of the methods, which has considerable practical value.

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    Centre Temperature Estimation of Blast Furnace Cross Temperature Measuring Based on M-SVR and RVFLNs
    ZHOU Ping,YOU Lei, LIU Ji-ping, ZHANG Xing
    2017, 38 (5):  614-619.  DOI: 10.12068/j.issn.1005-3026.2017.05.002
    Abstract ( 1031 )   HTML   PDF (767KB) ( 991 )  

    Due to the high temperature in the middle of blast furnace, the central position sensor of the cross temperature measuring is very easy to be damaged, and the replacement period is always long, resulting in the gas flow distribution not being observed in time. To this end, two kinds of data:based intelligent modeling methods of multi-output support vector regression machine (M-SVR) and random vector functional-link networks (RVFLNs) were used to establish the temperature estimation model of cross temperature measuring center of blast furnace. Finally, the temperature estimation model based on industrial data was verified and compared. The results show that both M-SVR model and RVFLNs model have good temperature estimation effect when the sample size is small. However, when the sample size is large enough, the generalization performance and estimation accuracy of M-SVR model is better than those of the RVFLNs model.

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    Camera Calibration Method Based on Distortion Separation
    LIU Xiao-zhi, QI Di-di, BEN Chi
    2017, 38 (5):  620-624.  DOI: 10.12068/j.issn.1005-3026.2017.05.003
    Abstract ( 737 )   HTML   PDF (495KB) ( 819 )  

    In the process of camera calibration, in order to avoid repeating calibration of the distortion coefficient in camera model, a distortion separated camera calibration method was proposed. The second order radial distortion was considered, in which the area of contour line formed by distortion is utilized as the criterion, and the inertia weight and learning factor of the particle swarm optimization algorithm based simulated annealing were improved. Then the improved particle swarm optimization algorithm was utilized to calibrate the distortion coefficient and principal point coordinate of the camera. Finally, the other camera parameters were calculated. The proposed method was simple and easy to implement without needing any internal and external parameters of the camera in advance. Experiments show that the proposed method has lower mean back-projection error and better robustness compared with the traditional nonlinear optimization methods.

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    A Similarity Search Technique for Graph Set
    PANG Jun, GU Yu, YU Ge
    2017, 38 (5):  625-629.  DOI: 10.12068/j.issn.1005-3026.2017.05.004
    Abstract ( 656 )   HTML   PDF (472KB) ( 967 )  

    Existing studies of graph similarity search mainly focus on the subgraph matching instead of the graph set matching. To tackle this issue, GSSS algorithm was proposed based on filtering-and-verify framework. A graph set distance was defined. In order to reduce the search space, Number filter, Size filter, Complete edge filter and Lower bound filter were proposed. Then, the computation of the graph set distance was optimized. An incremental multi-layer inverted index was designed to further improve the query efficiency. Extensive experiments on a real-world dataset show that GSSS algorithm is effective and efficient.

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    Research on FAST Node Displacement Prediction Based on ELM Neural Network
    SHA Yi, CHEN Xi, ZHANG Li-li, ZHU Li-chun
    2017, 38 (5):  630-633.  DOI: 10.12068/j.issn.1005-3026.2017.05.005
    Abstract ( 679 )   HTML   PDF (404KB) ( 1292 )  

    Due to the problems that the numbers of nodes in hidden layers of ELM neural network are in need of manual setting, and the over-fitting phenomenon is easy to appear, resulting in a reduction in the network generalization, an EM_ELM algorithm was proposed to improve ELM neural network based on error minimization. The feasibility was proved in theory which could improve the prediction accuracy and generalization of ELM neural network. Meanwhile, the algorithm was also applied into the model of FAST node displacement prediction and conducted simulation finally. The results show that although EM_ELM neural network is not sufficient in training time to a certain degree, it is still proper in real-time requirement. Besides, its prediction accuracy and generalization capabilities are enhanced, which is just a proof in the effectiveness and feasibility of the improved algorithm, thereby further illustrating that the EM_ELM neural network is more suitable for FAST node displacement prediction.

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    Performance Analysis and Study of Vehicular Ad Hoc Networks on Platoon
    ZHAO Hai, LEI Kai-ru, SI Shuai-zong, XU Zi-wen
    2017, 38 (5):  634-638.  DOI: 10.12068/j.issn.1005-3026.2017.05.006
    Abstract ( 783 )   HTML   PDF (645KB) ( 1002 )  

    Performance of platoon can be improved by vehicular ad hoc networks and cooperative adaptive cruise control system. A platoon management protocol and a platoon management strategy were proposed which could be applied to platoon vehicles and free vehicles in large scales. A vehicle mobility model which was simulated by SUMO for platoon scenes was designed. Meanwhile, a clustering protocol was designed which was simulated by NS2 for analyzing communication performance in large scales of platoon vehicles and free vehicles. The results prove that platoon can improve performance of road capacity and communication for vehicular Ad Hoc networks.

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    A Lung Cancer Detection Algorithm Based on CV Model and Improved ME Model
    PAK Chun-hyok, CAO Peng,ZHAO Hai, ZHU Hong-bo
    2017, 38 (5):  639-644.  DOI: 10.12068/j.issn.1005-3026.2017.05.007
    Abstract ( 794 )   HTML   PDF (2102KB) ( 1069 )  

    According to solve the problem that it is difficult to automatically detect lung nodule lesions in CT images, a lung cancer detection algorithm was proposed based on Chan-Vese model (CV model) and improved mean square error model (ME model). As the degree of fuzziness of nodular boundary is the most important indicator of evaluating lung nodule in CT images study, two interactive image segmentation algorithms were employed in the proposed method based on CV model and improved ME model to process the CT image. Since the shrinkage of these two algorithms vary, two different nodular boundaries were got, and the degree of fuzziness of nodular according to the boundary difference was computed. Lastly, by comparing the degree of fuzziness of nodular, the threshold value to diagnose cancer was determined. The experimental evaluation demonstrates that compared with existing methods, the algorithm can detect lung cancer with higher accuracy in CT images.

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    Materials & Metallurgy
    Texture Evolution of High Silicon Steel Ultra-thin Sheets During Cold Rolling
    LIU Jin-long, SHA Yu-hui, SHAO Guang-shuai, ZOU Liang
    2017, 38 (5):  645-650.  DOI: 10.12068/j.issn.1005-3026.2017.05.008
    Abstract ( 711 )   HTML   PDF (3961KB) ( 925 )  

    High silicon electrical steel ultra-thin sheets of 0.10mm thick, containing about 6.5% Si, were prepared by rolling method. The evolution of deformation texture during cold rolling was studied using X-ray diffraction. Then the methods of controlling deformation texture were proposed in favor of the λ (<100>//ND, normal direction) and η (<100>//RD, rolling direction) recrystallization texture, respectively. The rolling reduction between 50% and 70% is easy to promote the formation of the η recrystallization texture at the layer of S=0.5. While, the rolling reductions of either less than 30% or 91%~97% are in favor of λ recrystallization texture, in which the former reduction is more suitable to control the λ recrystallization texture when using a two-stage cold rolling method to prepare high silicon steel ultra-thin sheets.

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    Effect of Quenching Medium on Microstructure and Properties of Wear-Resistant Casting Steel
    ZHANG Ya-jing, FANG Sheng-min, WANG Jin-bao, ZHANG Guo-zhi
    2017, 38 (5):  650-654.  DOI: 10.12068/j.issn.1005-3026.2017.05.009
    Abstract ( 773 )   HTML   PDF (1130KB) ( 996 )  

    Microstructures and properties of 42CrMo steel and dual-phase wear-resistant steel after a quenching and tempering treatment were investigated, where water and quenching oil were used as quenching medium, respectively. The results show that both microstructures of the water-quenched+tempered and oil-quenched+tempered dual-phase wear-resistant steels are lath martensite, needle-like bainite and carbide. The microstructures of the water-quenched+tempered and oil-quenched+tempered 42CrMo steels are tempered martensite and retained austenite, and tempered martensite, ferrite and bainite, respectively. The optimum heat treatment and properties of 42CrMo steel and dual-phase wear-resistant steel can be obtained after the comparison of their microstructures and properties. As a result, the wear-resistant property of 42CrMo steel after water-quenching and tempering at 280℃ treatment is the best one, which is 1.558 times higher than that of a high manganese steel in a 480h low-stress abrasive wear experiment.

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    Numerical Simulation of Electromagnetic Field of Industrial Scale Electroslag Remelting Process
    YU Jia, LIU Fu-bin, JIANG Zhou-hua, CHEN Kui
    2017, 38 (5):  655-660.  DOI: 10.12068/j.issn.1005-3026.2017.05.010
    Abstract ( 752 )   HTML   PDF (1301KB) ( 914 )  

    A mathematical model is established to investigate the electromagnetic field phenomena in an industrial-scale electroslag remelting process, the coupled real and imaginary scalar equations of magnetic field intensity are simultaneously solved with FLUENT software. The distribution characteristics of electromagnetic field with 50Hz have been analyzed, and the effects of current frequency and electrode penetration depth on electromagnetic field are also investigated. The results indicate that the current density increases from 91 378A/m2 to 190 746A/m2 when the current frequency varies from 0.5Hz to 60Hz. The magnetic field intensity concentrates in the region adjacent to the surface of electrode and ingot with the current frequency increasing. In addition, it also results in the alteration of the direction of Lorentz force at the slag-pool interface. Under the condition of the same power input, the Joule heating density in slag far from the electrode tip increases with the electrode penetration depth, however, it decreases at the region adjacent to the electrode tip.

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    Analysis of Flue Gas SO2 Distribution and Influencing Factors During Sintering Process
    JIA Feng-rui, WANG En-gang, HE Ji-cheng, DONG Hui
    2017, 38 (5):  661-666.  DOI: 10.12068/j.issn.1005-3026.2017.05.011
    Abstract ( 744 )   HTML   PDF (549KB) ( 834 )  

    Based on the SO2 absorption-emission mechanism, a model for computing flue gas SO2 concentration distribution during sintering was established. After the comparison of the computional results and the in-site data from a 360m2 sinter machine in China, the model was validated. Then, the factors influencing on the flue gas distribution were investigated, including the sinter-bed height, speed, carbon content and moisture content. The results indicate that the flue gas SO2 distributes as a Cubic curve along the sinter machine length. The peak value of the SO2 concentration arrives earlier with higher carbon content and lower sinter-bed height, slower speed and lower moisture content, and the first three ones affect the flue gas SO2 concentration more. The SO2 concentration from the top to one-third of the sinter machine in the length direction is less 200mg/m3, when the sinter-bed height, sinter-bed speed and the moisture and carbon content is, 650~700mm, 2.3m/min, 7%and 3%,respectively.

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    Experimental Studies on Asymmetrical Flow and Vortex Slag Entrapment in Continuous Casting Mold
    LIU Zhong-qiu, LI Bao-kuan
    2017, 38 (5):  666-670.  DOI: 10.12068/j.issn.1005-3026.2017.05.012
    Abstract ( 709 )   HTML   PDF (881KB) ( 920 )  

    The asymmetrical flow inside the mold and the slag entrapment induced by vortex at the top surface have great influences on the quality of continuous casting slab. One vertical-curved mold system was set to study the asymmetrical flow and slag entrapment behaviors. The results show that the asymmetrical flow in the mold is induced by the instability of the flow field itself and the flow pattern is not stationary but changed over frequently. The asymmetrical flow occurs near the bending section of the secondary cooling zone. Although the geometrical and operating conditions were made to be symmetric strictly, the vortex cannot be avoided. In the most cases, only one vortex took place and its size and position varies with time. The probability, size and strength of the symmetric vortex are very small and the durations is also short. Moreover, the effects of casting speed, gas injection rate, immersion depth of nozzle, slide gate opening, and liquid level height of tundish on the periodic asymmetrical flow and slag entrapment are analyzed.

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    Synthesis of LiCrxMn2-○x○O4 by Sol-Gel Assisted High Temperature Ball Milling
    GENG Shu-dong, ZHAI Yu-chun
    2017, 38 (5):  671-675.  DOI: 10.12068/j.issn.1005-3026.2017.05.013
    Abstract ( 591 )   HTML   PDF (1753KB) ( 763 )  

    Spinel LiCrxMn2-○x○O4 cathode material was synthesized by sol-gel assisted high temperature ball milling method using LiOH·H2O, Cr(CH3COO)3·6H2O and Mn(CH3COO)2·4H2O as raw materials . The crystal structure, surface morphology and charge-discharge performance of materials by doping different amounts of Cr were studied. The results show that the capacity retention rate of the material is greatly improved by Cr doping. The discharge capacity of the material decreases with the increasing doping amounts of Cr. The discharge specific capacity of LiCr0.2Mn1.8O4 is lower than that of LiMn2O4. The charge-discharge performance of LiCr0.05Mn1.95O4 is optimal and its initial discharge capacity is 119.6mAh/g and the discharge capacity retention rate is 97.4% after 40 cycles at a rate of 0.1. Furthermore, the discharge capacity retention rate is 96.3% after 100 cycles at various rates from 0.1 to 2.0.

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    Mechanical Engineering
    On the Calculation Method for the Reliability of Chatter Stability in CNC Milling
    HUANG Xian-zhen, HU Sen, ZHANG Yi-min
    2017, 38 (5):  675-679.  DOI: 10.12068/j.issn.1005-3026.2017.05.014
    Abstract ( 906 )   HTML   PDF (493KB) ( 1085 )  

    The system parameters in the process of milling generally have randomness, which influences the stability of milling. The neural network was used to make a comprehensive analysis of the effects of random factors in milling, and a method for the reliability analysis of regenerative chatter stability in milling was proposed. A dynamic model for regenerative chatters of milling was established, and the stability lobe diagram was obtained by means of full discretization.The neural network was applied to approximate the functional relationship of the limit axial cutting depth,and the reliability was then calculated with the Monte Carlo method and first order second moment method, respectively. Finally, the results of an example were used to demonstrate the efficiency and accuracy of the proposed method based on the neural network.

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    Detection of Depth Plate Defect Based on Dimensional Analysis and Thermal Image
    LI Chang-you, YANG Yong, GUO Song, ZHANG Yi-min
    2017, 38 (5):  680-684.  DOI: 10.12068/j.issn.1005-3026.2017.05.015
    Abstract ( 578 )   HTML   PDF (1018KB) ( 719 )  

    A method combining dimensional analysis with thermal image is proposed to quantitatively detect the defect depth of plates. The thermal analysis model of defective plates is built with the finite element method and verified by the known experimental data. Then, the influence factors of the time of maximum temperature difference between the defective and intact parts are analyzed and the corresponding relationship between the time and the factors is derived by means of dimensional analysis. The corresponding relationship is formulated by fitting the simulation data of the thermal analysis model. Compared with the other defined temperature difference methods, the proposed method is more comprehensive, which could detect the defect depth of plates more accurately, as the result shows.

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    Chatter Reliability Prediction in the Turning Process with Time-Varying Stability
    LIU Yu, WANG Zhen-yu, YANG Hui-gang, ZHANG Yi-min
    2017, 38 (5):  684-689.  DOI: 10.12068/j.issn.1005-3026.2017.05.016
    Abstract ( 724 )   HTML   PDF (1347KB) ( 881 )  

    Tool wear in the machining process changes the cutting force coefficient and other parameters in flux, which causes the prediction accuracy of traditional chatter prediction to decrease greatly with the increase of processing time. The time-varying reliability theory was introduced to predict chatter reliability, and the linear equations were used to express the change inthe mean values of cutting force coefficient with varied cutting time whereby the chatter stability and reliability model in turning was presented. The time-varying critical cutting width and time-varying chatter reliability curve were obtained in the given machining conditions, and the corresponding calculation method was tested experimentally. The results showed that the proposed method can be used to predict the chatter of different processing time accurately.

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    Fatigue Properties of Fiber Reinforced Al-Li Alloy Laminates Under the Conditions of Different Loading Modes
    MENG Wei-ying, XIE Li-yang, LIU Jian-zhong, TONG An-shi
    2017, 38 (5):  690-694.  DOI: 10.12068/j.issn.1005-3026.2017.05.017
    Abstract ( 614 )   HTML   PDF (841KB) ( 761 )  

    The 2/1 laminates and 3/2 laminates of fiber reinforced Al-Li alloy were taken for fatigue life tests. Each type of the materials was applied to cyclic stress, which has different cycle characteristics (constant amplitude with the stress ratio -1, high and low load and Mini-Twist spectrum load). Six kinds of test data on stress life were obtained and the P-S-N curve of each material was fitted by using the principle of sample polymerization. The S-N curve differences of varied materials in the same loading mode were compared with each other in order to analyze the fatigue performance characteristics of the materials with different compounding patterns. The results showed that in the range of 5×104~5×105 life, the fatigue life performance of 3/2 laminate materials is better than that of 2/1 laminates under constant amplitude and high and low load; and the fatigue life performance of 3/2 laminate materials is superior to that of 2/1 laminates on the whole under Mini-Twist spectrum load.

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    Oil Film Pressure Characteristics of Liquid Hybrid Bearings in the CNC Lathe
    ZHANG Yao-man, YIN Xin-xian, LIN Xiu-li, YOU Zhao-peng
    2017, 38 (5):  695-699.  DOI: 10.12068/j.issn.1005-3026.2017.05.018
    Abstract ( 826 )   HTML   PDF (1538KB) ( 846 )  

    The spindle assembly of the highly precised CNC lathe was taken as the object, and the theoretical modeling of oil film pressure and the simulation analysis method of the hybrid bearing were studied. First, the Reynolds equation and the oil film’s loading capacity equation were transformed into dimensionless forms, and then the numerical method was used to solve the equation. Accordingly, the dimensionless of oil film pressure distribution and pressure values in different regions and the distribution regularity were obtained by further solving. In addition, the characteristics of oil film pressure distribution and the pressure field in different supply pressures and spindle speeds were obtained by using the fluid dynamics analysis software.The analysis results also provided important reference for further studies on the loading capacity and hybrid bearing design . The feasibility of theoretical modeling and simulation methods were also verified by comparing the results of theoretical analysis and simulation analysis.

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    Multivariate Correlative and Combined Thermal Error Model for the CNC Machine Tool with Experimental Validation
    MA Yue, WANG Hong-fu, SUN Wei, HUANG Yu-bin
    2017, 38 (5):  700-705.  DOI: 10.12068/j.issn.1005-3026.2017.05.019
    Abstract ( 657 )   HTML   PDF (1269KB) ( 985 )  

    To solve the problem that based on machine tool temperature that is comprehensively influenced by other factors, and thus the thermal error models had poor robustness, a multivariate correlative and combined thermal error model was put forward, which overall considers machine tool temperature, speed of power source, and temperature of coolant and environment. Least squares support vector (LS-SVM) method was applied to the thermal error model, and partial least squares (PLS) method was applied to extract the principal components as the input of LS-SVM, and the PLS-LSSVM thermal error combined model was then formulated. In addition, this model set the differential temperatures, relatively with initial temperatures, as the temperature variable, which is based on the process of numerical control machining and the principle of material thermal deformation, to make the thermal error compensation more accurate. It was tested on a precision machining center, whose results showed that the PLS-LSSVM thermal error model is more stable than the LS-SVM model, and more accurate than the partial least squares regression (PLSR) model. Besides, the root mean square error (RMSE) of the predictive thermal error with the PLS-LSSVM model is 5.5μm on average less than that with the PLS-LSSVM* model, which only takes into account the temperature measurements of the machine tool.

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    Fuzzy Fault Tree Analysis of the Cycloid Enveloping Reducer
    LI Chao-yang, JIANG Yun-zhe, CHEN Bing-kui
    2017, 38 (5):  706-711.  DOI: 10.12068/j.issn.1005-3026.2017.05.020
    Abstract ( 603 )   HTML   PDF (709KB) ( 725 )  

    Based on the structural characteristics of the new cycloid enveloping reducer, a fault tree model of the reducer was established. Considering such uncertain factors of the new cycloid reducer as fault phenomenon, fault probability and fault cause under actual conditions, the fuzzy sets theory was introduced into fault tree analysis. The triangular fuzzy numbers were utilized to qualify the probability of fault causes. Mean while, the fuzzy probability of failure and fuzzy importance measure of fault causes were calculated based on the λ cut-set theory and interval arithmetic. The results showed that the cycloid enveloping reducer has a high reliability and the wear of rollers, raceways and cycloid teeth profiles, and the failure of crankshaft bearings are the key influence factors for the reliability of the cycloid enveloping reducer.

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    Resources & Civil Engineering
    Process Mineralogy of Gold Ore in Zaozigou Gold Mine, Gansu Province
    DONG Zai-zheng, GAO Peng, ZHANG Shu-min, HAN Yue-xin
    2017, 38 (5):  711-715.  DOI: 10.12068/j.issn.1005-3026.2017.05.021
    Abstract ( 985 )   HTML   PDF (1265KB) ( 907 )  

    The samples collected from Zaozigou gold mine in Gansu Province can be considered as typical Carlin-type gold deposits. The Au, Sb, and As contents of the ore are 4.09g/t, 0.46% and 0.39 %, respectively. It was found that the main metallic minerals in the gold ore are pyrite, arsenopyrite, stibnite and limonite. The primary gangue minerals are quartz, carbonate minerals and sericite. Mineral composition of the ore is complex, however, gold and antimony are the only useful minerals. The gold minerals in the ore are mainly native gold with the relative content of 99.12%. In addition to gold distributed in the gangue minerals, stibnite is an important carrier of gold. Particle size of native gold is tiny less than 0.075mm and nonuniform. According to the process mineralogy research, the main reasons for the refractory of the ore are the easily argillaceous minerals, inclusion gold and containing huge amounts of minerals consuming cyanide such as arsenic antimony matter.

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    Mechanism Study of Direct Flotation on Malachite by Sodium Oleate
    SUN Qian-yu, YIN Wan-zhong, CAO Shao-hang, YAO Jin
    2017, 38 (5):  716-720.  DOI: 10.12068/j.issn.1005-3026.2017.05.022
    Abstract ( 825 )   HTML   PDF (623KB) ( 1200 )  

    The flotation behavior and action mechanism of sodium oleate as collector for direct flotation of malachite was studied.The adsorption mechanism of sodium oleate on the surface of malachite was investigated through the adsorption measurement, Zeta potential test, Fourier transform infrared spectroscopy analysis, and solution chemistry calculation and thermodynamic calculation of solution.The results showed that the recoveries of malachite are more than 70% at pH value from 7 to 10 with sodium oleate 160mg/L, which reached the highest value 88.67% at pH=9.5. The Zeta potential measurement and solution chemical calculation indicated that sodium oleate mainly emits the chemical adsorption on the surface of malachite, the active component are C17H33COOH·C17H33COO-, C17H33COO- and (C17H33COO)2-2 in sodium oleate solution. The results of Gibbs free energy calculation and FTIR spectrum analysis confirmed that oleate ions tends to react with malachite surface to form copper oleate precipitation causing malachite’s flotability.

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    Dispersion Mechanism of Citric Acid in Flotation System of Hematite Containing Carbonate
    YAO Jin, LI Dong, YIN Wan-zhong, HAN Hui-li
    2017, 38 (5):  720-724.  DOI: 10.12068/j.issn.1005-3026.2017.05.023
    Abstract ( 793 )   HTML   PDF (613KB) ( 992 )  

    Sedimentation tests, Zeta potential measurements, FTIR (Fourier transform infrared spectros copy) spectroscopy, and solution chemistry calculations were used to investigate the dispersion mechanism of citric acid in strong alkaline conditions (pH=11.0). The sedimentation testing results show that the mixed minerals (containing hematite, siderite, and quartz) can be partly dispersed by citric acid. The results of Zeta potential measurements and FTIR spectroscopy indicate that citric acid mainly absorbs on siderite and hematite surface and partly brings their Zeta potentials down, while the Zeta potential of quartz is slightly influenced and the adsorption of citric acid on quartz surface is weak. The solution chemistry calculations indicate that citric acid interacts with the hydroxylation surface of hematite and siderite by the form of [C6H5O73- toprevent the coagulation of minerals, which might explain the dispersion mechanism of citric acid in flotation system of hematite containing carbonate.

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    Modeling of the Influence of Pore Size and Porosity on Strength Characteristics of Volcanic Rock
    CHEN Chong-feng, XU Tao, HEAP Michael,YANG Tian-hong
    2017, 38 (5):  725-729.  DOI: 10.12068/j.issn.1005-3026.2017.05.024
    Abstract ( 761 )   HTML   PDF (2459KB) ( 1238 )  

    Based on the study of the pore structure of volcanic rock, the uniaxial compression process of volcanic rock was numerically performed to investigate the influence of pore size and porosity on strength characteristics of volcanic rock using rock failure process analysis system (RFPA2D). The results show that under the pore size increasing from 0.1 to 0.3 mm, reduction percentage of ultimate strain with the increase of porosity keeps fluctuation within a certain range, elastic modulus’ reduction percentage increase with the increase of porosity and shows a linear increasing trend. Under the same porosity, the influence of pore size mainly shows that, with the increasing of the pore size, failure mode of the samples gradually tends to split fracture.

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    A Stratigraphic Thickness Control Algorithm in 3D Structural Modeling
    CAO Kai, PAN Mao, SUN Peng
    2017, 38 (5):  730-735.  DOI: 10.12068/j.issn.1005-3026.2017.05.025
    Abstract ( 664 )   HTML   PDF (588KB) ( 801 )  

    In 3D stuctural modeling, during construction of the stratigraphic surface, unreasonable stratigraphic thickness often arises by the interpolation point that is not consistent with the actual geological conditions. To address this problem, a new method for the thickness control is proposed. Firstly, a model of spatial index and OBB collision for triangulated irregular network is established. Secondly, according to the model, the position of the layer with unreasonable thickness is found out by intersection test. Thirdly, with the thought of geometry subdivision in topology, the thickness control is performed on zero and one dimensions. This method has been successfully applied in petroleum and mine field. The results show that the algorithm is fast, stable and reliable. It can be used to control the thickness of the layer automatically, avoiding massive manual interaction operations of thickness adjustment.

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    Stability Studies of Reservoir Landslide Under Reservoir Water Level Fluctuation
    SONG Dan-qing, SONG Hong-quan
    2017, 38 (5):  735-739.  DOI: 10.12068/j.issn.1005-3026.2017.05.026
    Abstract ( 651 )   HTML   PDF (1373KB) ( 900 )  

    For studying the influence of reservoir water fluctuation on reservoir landslide stability, taking a landslide in Jiudianxia reservoir area as an example, the external deformation of landslide is monitored by GPS, and the change law of landslide stability is analyzed in combination with detailed field investigation and reservoir operation data, which is also numerically analyzed by Geo-slope as well. The results show that the landslide has three fast movements in phase of 100~130m, and continuous rapid water rise and fall will trigger landslide movement. The landslide stability decreases with the increase of water fall speed, and the landslide will occur if water fall speed is more than 0.3m/d. The landslide also will occur when water rise speed is more than 0.5m/d. The landslide movement presents a typical time-dependent characteristics, and a lag time can be identified between rapid water fluctuation and landslide movement.

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    Automatic Picking of Microseismic Events P-wave Arrivals Based on Improved Method of STA/LTA
    LIU Xiao-ming, ZHAO Jun-jie, WANG Yun-min, PENG Ping-an
    2017, 38 (5):  740-745.  DOI: 10.12068/j.issn.1005-3026.2017.05.027
    Abstract ( 1133 )   HTML   PDF (613KB) ( 1601 )  

    An improved method of automatic picking P-wave first arrival time based on the method of STA/LTA was put forward. A new kind of characteristic function was established by introducing weighting factor K, the global maximum on the curve of STA/LTA was found, then the corresponding moment is identified as the arrival of P-wave, and Matlab was used to analyze seismic events. Results show that the method can accurately pick up P-wave arrivals of seismic event, and reduce the process of adjusting the trigger threshold (Thr) to pick up the P-wave of the traditional algorithm (STA/LTA), and overcome the shortcoming that a fixed threshold can not pick the arrival time of complex signals. And the method has advantages of strong noise resistance, good stability, etc.

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    Research on Static Stability of ±800kV Suspension Cable Guyed Tower
    XIAO Zheng-zhi, WEN Hang, LI Zheng-liang
    2017, 38 (5):  746-750.  DOI: 10.12068/j.issn.1005-3026.2017.05.028
    Abstract ( 650 )   HTML   PDF (486KB) ( 761 )  

    To solve the problem of static stability of ±800 kV suspension cable guyed tower, equivalent elastic modulus formula of suspension cable is firstly derived based on the generalized variational principle. Then according to the strain energy, the equivalent column attributes of equivalent cross section are obtained. According to the force characteristics of suspension cable guyed tower column, it is simplified to the bar with uniform cross section which is hinged at the bottom and is supported elastically at the top. Finally, based on compressive bar stability theory, the relationship of calculation length coefficient of guyed tower column is got, the initial pretension and wind speed. The study results show that the static calculated length coefficient of column in windward side and column in leeward side along vertical transmission line direction is one, wind load and initial pretension have great impact on static calculated length coefficient of column in leeward side along transmission line, which rapidly increases with an increase in wind speed when initial pretension is lesser, but wind speed has a minor effect on it when initial pretension exceeds a certain value.

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    Management Science
    Impact Mechanism of Dissociative Group on Brand Avoidance
    HAO Jin-jin, MA Qin-hai, FAN Guang-wei
    2017, 38 (5):  751-755.  DOI: 10.12068/j.issn.1005-3026.2017.05.029
    Abstract ( 723 )   HTML   PDF (401KB) ( 847 )  

    To investigate the impact of dissociative group on brand avoidance,the empirical research method was used, and a theoretical model was constructed to test the hypotheses. A questionnaire was administered to collect data, and such analytic tools as SPSS and AMOS were used for data analysis. The results showed that dissociative group has a significant positive effect on brand avoidance and undesired self-congruence, while it has a significant negative effect on self-brand connection; undesired self-congruence is a full-mediator between dissociative group and self-brand connection; self-brand connection is a semi-mediator of undesired self-congruence and brand avoidance; brand involvement negatively moderates the relationship between dissociative group and brand avoidance as well as the relationship between dissociative group and undesired self-congruence.

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    Micro-credit Companies’ Operating Mechanism Based on Evolutionary Game Theory
    CHE Tai-gen○, ZHUANG Xin-tian, SU Yan-li
    2017, 38 (5):  756-760.  DOI: 10.12068/j.issn.1005-3026.2017.05.030
    Abstract ( 717 )   HTML   PDF (354KB) ( 720 )  

    By establishing the evolutionary game model for micro-credit companies and small and micro businesses, the operating mechanism of micro-credit companies was analyzed. It was found that in the patterns of lending, micro-credit companies should manage guaranteed loans; in the guarantee mechanism, micro-credit companies should adopt shortfall guarantee; in the risk classification and identification, the judgment criterion should be the relationship among average success rate, interest rate, and guarantee rate of small and micro businesses’ investment projects; in the loan index, the high-quality small and micro businesses should be entitled to the interval management of guaranteed rates and reduced interest rates, while for the ordinary small and micro businesses the border management of guarantee and interest rates should be adopted, and the actual value should be up close to the boundary value; in the external policy, the third-party guarantee rates should be reduced through policy making.

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