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15 June 2017, Volume 38 Issue 6 Previous Issue    Next Issue
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Information & Control

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Control Strategy for the Compensation of Imbalance and Harmonic in Energy Internet HUANG Bo-nan， ZHOU Jian-guo， SUN Qiu-ye， ZHANG Hua-guang 2017, 38 (6):  761-766.  DOI: 10.12068/j.issn.1005-3026.2017.06.001 Abstract ( 738 )   HTML   PDF (1403KB) ( 1735 )   The energy internet proposed recently provides a potential solution to address the increasingly serious world energy issues. Solving the power quality problem properly is one of the key problems of the energy internet to be developed adequately in the future. Considering the power quality issue caused by the nonlinear and imbalance loads widely existing in the energy internet， an imbalance and harmonic compensation strategy is proposed based on the energy router in this paper. The imbalance and harmonic compensation controllers are also developed in detail. Simulation results from MATLAB/SIMULINK are provided to demonstrate the validity and efficiency of the proposed method. References | Related Articles | Metrics

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Power Line Carrier Communication Based on CSMA/CA and Its Application in Lighting System YU Jian-bo， ZONG Wei-zhou， CHENG Hui 2017, 38 (6):  766-771.  DOI: 10.12068/j.issn.1005-3026.2017.06.002 Abstract ( 675 )   HTML   PDF (1089KB) ( 737 )   Distributed control system focuses on the data acquisition， centralized management and centralized control of the circuit through independent multi-subsystem. Receiver and transmitter of power line share the same communication channel when message is transferred by terminals， which will give rise to data disorder. An anti-collision PLC technology based on CSMA/CA mechanism was proposed to solve the shortcoming， by which the stability and reliability of the communication could be improved. After analyzing the principle of data collision， the calculation model of the time which was used to transmit message between terminals simultaneously was established. Monte Carlo method was presented to compute the expectation of delay time. The feasibility of this technique was verified in engineering experiments. Sensitivity analysis was made to verify the factors that affect the delay time. The results provide a theoretical and practical basis of the design of intelligent lighting system. References | Related Articles | Metrics

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A Multi-objective VPGA for Optimization Design of PMECD Based on Equivalent Magnetic Circuit Model WANG Da-zhi， SHI Tong-yu， LI Shuo， YU Lin-xin 2017, 38 (6):  772-777.  DOI: 10.12068/j.issn.1005-3026.2017.06.003 Abstract ( 590 )   HTML   PDF (825KB) ( 732 )   Based on equivalent magnetic circuit model， an optimum design method of permanent magnet eddy current driver (PMECD) was proposed by the variable population-size genetic algorithm (VPGA) which taken death and war factors into account. Firstly， analytical model was built and the analytical formulas of key parameters were deduced. On this basis， by using permanent magnet thickness， pole-arc coefficient， copper plate thickness and the number of permanent magnets as variables and taking output torque， rotational inertia and the volume of the driver as optimization goals， a multi-objective optimization function with entropy coefficients and the VPGA were proposed to optimize parameters structure of the driver. The validity and feasibility of the proposed method were proved by finite element analysis and experimental results. The results confirm that compared with other two optimization algorithms， optimization design result by the VPGA based on the analytical model has good effect on optimization of structural parameters. References | Related Articles | Metrics

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Application of Neural Network Predictive Control in SCR Flue Gas Denitration System MENG Fan-wei， XU Bo， LYU Xiao-yong ， LIU Yin-qi 2017, 38 (6):  778-782.  DOI: 10.12068/j.issn.1005-3026.2017.06.004 Abstract ( 770 )   HTML   PDF (880KB) ( 863 )   Based on the data collected from selective catalytic reduction (SCR) reaction system of a 350MW coal-fired unit in a thermal power plant， neural network predictive control method was used to study the prediction and control of nitrogen oxides emission in power plant tail gas. Firstly， the non-linear model of SCR denitrification system was modeled and nonlinear autoregressive model was used to estimate the model. Then， by using the predictive control method to control the ammonia injection， the tail gas could achieve the standard of discharge limitation， and the amount of ammonia and ammonia escape could also be reduced， resulting in the enhancement of economic efficiency. The controller was optimized by the steepest gradient method and the control variable was constrained by the performance function to achieve the expected output. Finally， compared with the measured date in the field， the simulation results show that the neural network predictive control scheme can predict the amount of ammonia sprayed in the future at a finite time. References | Related Articles | Metrics

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Internal Model PI Control of Refiner Load for Mechanical Pulping Process LI Ming-jie， ZHOU Ping 2017, 38 (6):  783-788.  DOI: 10.12068/j.issn.1005-3026.2017.06.005 Abstract ( 577 )   HTML   PDF (497KB) ( 754 )   The double disks refiner has large time delay， large inertia and nonlinear characteristics during operation， whereas the internal model control， as an advanced control strategy， given its advantages of not requiring high accuracy in the process model. A PI control method was proposed based on internal model control principle， which has only one adjustable parameter in the designed controller， achieving tuning by maximum sensitivity indicator， thus the complexity and randomness of controller tuning could be effectively avoided. Simulation results show that， compared with the conventional PID control， the model parameters variations and alleviate various interference on system performancecan be effectively reduced by using the proposed method， and the requirements of mechanical pulping process for controller properties can be satisfied to ensure the stable control of the mill load， laying the foundation for the implementation of the integrated automation system for pulping process. References | Related Articles | Metrics

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Subspace Projection Based Compressive Sensing SFGPR Imaging Algorithm SUN Yan-peng， ZHANG Shi， QU Le-le ， BAI Wen-jing 2017, 38 (6):  789-793.  DOI: 10.12068/j.issn.1005-3026.2017.06.006 Abstract ( 695 )   HTML   PDF (590KB) ( 757 )   The traditional compressive sensing (CS) stepped frequency ground penetrating radar (SFGPR) imaging algorithm usually loses effect in strong clutter environment. To alleviate this problem， a CS SFGPR imaging algorithm based on the subspace projection clutter suppression technique was proposed. The original uniform frequency sampling data at each measurement position were reconstructed from the reduced set of randomly measured data using CS measurement model. Then the subspace projection clutter suppression technique was employed to suppress the strong ground reflection signal. Finally the sparse reconstruction algorithm was used to reconstruct the image of underground targets. The experimental data has verified the validity and effectiveness of the proposed imaging method. References | Related Articles | Metrics

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A Technique for Processing Location-aware Preference Queries LI Miao， GU Yu， YU Ge 2017, 38 (6):  793-797.  DOI: 10.12068/j.issn.1005-3026.2017.06.007 Abstract ( 670 )   HTML   PDF (642KB) ( 754 )   There has been increasing popularity of online location-based services. It gives prominence to various types of spatial-keyword queries， which are employed to provide fundamental querying functionality for location-based services. A technique for processing location-aware preference queries was studied that aimed to find a destination place for a user. The user wants to go to a place labeled with a specified category feature (e.g.， hotel)， and he/she has a location and a set of additional preferences. It was expected that the result place of the query belongs to the specified feature， and it was close to places satisfying the preferences of the user. A novel framework was developed for answering the queries， which was called augmented IR-tree. An augmented IR-tree could be obtained by adding the pre-computed information into an IR-tree. The augmented IR-tree could be used to reduce the search space and compute the exact query result. The proposed technique was verified by extensive experiments on one real dataset， and the technique is more efficient than baseline methods. References | Related Articles | Metrics

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Tumor Microarray Gene Expression Data Classification Based on Weighted Extreme Learning Machine JIANG Lin-ying， YU Dong-hai， SHI Xin 2017, 38 (6):  798-803.  DOI: 10.12068/j.issn.1005-3026.2017.06.008 Abstract ( 777 )   HTML   PDF (594KB) ( 897 )   With the development of gene microarray technology， gene expression profiling becomes a significant method for identifying different types of canners. Microarray gene expression data is from clinical trials in general， where the class distribution of samples is changeable， which makes the expression data have a chance to become more imbalanced. In this paper， the weighted extreme learning machine (WELM) was used to classify the imbalance microarray gene expressing data. In order to reduce classification error caused by the imbalance data， a weight was assigned to each sample in order to enhance the impact of minority class while reducing majority class’s impact， and improve the accuracy of tumor classification. The experimental results show that the minority class recognition rate can be well improved by the proposed method， so as to improve the overall performance of classifiers. References | Related Articles | Metrics

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Study on Earthquake Weighted Network Based on Time-Space Influence Domain XU Jiu-qiang， ZHAO Nan， HE Xuan， ZHAO Hai 2017, 38 (6):  804-808.  DOI: 10.12068/j.issn.1005-3026.2017.06.009 Abstract ( 558 )   HTML   PDF (455KB) ( 689 )   In order to study the time-space complexity of seismic activity， in view of the difference in the interaction between seismic activity regions， an earthquake weighted network construction method based on time-space influence domain was put forward. California seismic data in 1984~2014 was selected to structure the earthquake weighted network， and its basic properties and connection properties of the network nodes were analyzed to reveal the inner link of earthquake activity. Experiments show that the link-weight distribution and the node-weight distribution can be described by power law; the relationship of node-weight and node-degree show that， for the property of this earthquack weighted network， the moderate-strong shock is as important as the large shock; by the study of the average neighbor degree and the clustering coefficient of seismic weighted network， it was found that strong shock regions are tend to be linked to strong connection. The above results show that the weighted network can help us find some internal relations of seismic system which cannot be found through the unweighted network. References | Related Articles | Metrics

Materials & Metallurgy

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SH-CCT Diagram， Microstructure and Properties of Coarse Grain Heat-Affected Zone in Q1100 Ultra-high Strength Steel WEN Chang-fei， DENG Xiang-tao， WANG Zhao-dong， WANG Guo-dong 2017, 38 (6):  809-813.  DOI: 10.12068/j.issn.1005-3026.2017.06.010 Abstract ( 1013 )   HTML   PDF (5020KB) ( 1525 )   It is generally believed that coarse grain heat-affected zone (CGHAZ) in welded region is the weakest part in the welding joint of low alloy ultra-high strength steel. The thermomechanical simulator was employed to simulate the welding thermal cycle processes of CGHAZ in Q1100 ultra-high strength steel. By using thermal expansion measurement combined with OM，SEM observations and hardness test， the critical phase transformation points at the equilibrium state and welding conditions were determined and SH-CCT diagram at different cooling rates was plotted. TEM observation and Lepera reagent were used to reveal the morphology of M-A constituent. The results showed that the austenitizing temperature of this steel in the welding condition was significantly higher than that in equilibrium state. The microstructure of CGHAZ mainly consisted of bainite， bainite and martensite， and martensite accompany with the increase of cooling rate. The hardness increased gradually with the increase of cooling rates， the maximum hardness was HV464. The M-A constituent occurred when the cooling rate was lower than 10℃/s， and the lower cooling rate， the more M-A constituent. References | Related Articles | Metrics

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Low Temperature Combustion Synthesis and Characterization of Nanocrystalline Magnesium Aluminum Spinel (MgAl2O4) Powders HUO Di， PI Chun-yang， SUN Xu-dong， KANG Yan 2017, 38 (6):  814-818.  DOI: 10.12068/j.issn.1005-3026.2017.06.011 Abstract ( 1090 )   HTML   PDF (2366KB) ( 1014 )   Nanocrystalline magnesium aluminate spinel (MgAl2O4) powders were prepared by a low temperature combustion synthesis method using nitrates and sucrose as starting materials， the characteristics of the as-synthesized powders were investigated in terms of heating temperature， environmental atmosphere and heating rate. The results show that particle sizes of MgAl2O4 spinel powder increase with the heating temperature of polymer precursors. When the precursors are heated in O2 atmosphere， the reduced formation temperature of pure MgAl2O4 phase and accelerated reactive species diffusion along with enlarged particle sizes can be achieved. Under the conditions of fast heating， 2∶1 molar ratio of sucrose to nitrates and O2 atmosphere， the formation temperature of MgAl2O4 phase is at 400℃ and further pure single phase is obtained at 700℃. The highly crystalline， soft agglomerated nano-sized MgAl2O4 powders are in favor of decreasing sintering temperature of high dense MgAl2O4 ceramics. References | Related Articles | Metrics

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Numerical Simulation of Counter Flow Natural Draft Wet Cooling Tower with Flue Gas Injection NIU Ran， LI Lin-min， WEN Xue-yu， LI Bao-kuan 2017, 38 (6):  819-822.  DOI: 10.12068/j.issn.1005-3026.2017.06.012 Abstract ( 666 )   HTML   PDF (827KB) ( 992 )   Aiming at working characteristics of different zones in cooling tower， a three-dimensional numerical model of counter flow natural draft wet cooling tower with flue gas injection was established based on the theories of heat/mass transfer and flow between air and water. The motion of continuous and dispersed phases in cooling tower was investigated by Euler-Lagrange approach and the effect of cooling performance by setting up flue gas injection had also been taken into account. Meanwhile， the working performance of cooling tower under diverse crosswind velocities was analyzed， in contrast with that in a traditional cooling tower without flue gas injection. The results showed that the setup of flue gas injection had positive effect on the working efficiency of cooling tower. The crosswind decreased the drop degree of cooling water， which was harmful to gas emission. Moreover， crosswind could also increase corrosion drastically near the tower outlet. References | Related Articles | Metrics

Mechanical Engineering

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Influence of Randomness of Structure Parameters for Bearings on Its Stiffness Sensitivity FENG Ji-lu， SUN Zhi-li， XU Er-feng， SUN An-bang 2017, 38 (6):  823-828.  DOI: 10.12068/j.issn.1005-3026.2017.06.013 Abstract ( 647 )   HTML   PDF (807KB) ( 994 )   The latin hypercube sampling technique was used to obtain sample points of structure parameters for angular contact ball bearings. A combination method of the Powell algorithm and Newton-Raphson method was proposed for solving nonlinear equations and then the as-obtained the bearings stiffness were applied on fitting response surface functions based on the Kriging model. The influence of the mean and variation of structure parameters for angular contact ball bearings on its stiffness sensitivity was simulated using the Monte Carlo method. The results show that the mean and variation of structure parameters for angular contact ball bearings have an adverse effect on the sensitivity of the axial and radial stiffness. Bearings stiffness is most sensitive to the variation of ball diameters， then curvature radius of the inner and outer raceway groove takes the second place， and the outer raceway diameter is the least. This research may bring forward the theoretical basis for selecting the design parameters and machining accuracy of bearings as well as separation of parts. References | Related Articles | Metrics

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EEG Feature Analysis of Expert Operators in Grinding Process Control ZHANG Chi， LU Shao-wen， WANG Hong， WANG Hong* 2017, 38 (6):  828-833.  DOI: 10.12068/j.issn.1005-3026.2017.06.014 Abstract ( 559 )   HTML   PDF (1396KB) ( 733 )   In the context of systematic optimization and intelligent upgrade of the mineral production， the assessment and quantification of the operators’ behavioral factors need to be investigated to further enhance productivity and quality of the products. A real-time analysis method based on the electroencephalography (EEG) characteristics was presented in grinding process. To begin with， the δ， θ， α， and β rhythms in different brain regions were extracted using wavelet decomposition. Then the wavelet entropy can be obtained by calculating the energy sequence distribution of different wavelet coefficient vectors. According to the comparison of the entropy values， the specific brain region was selected. Through wavelet time-frequency analysis， (α+β)/(δ+θ+α+β) was determined as the spectral characteristic. Finally， the results of real-time analysis using B-spline curve and sliding window showed that the physiological indicators can reflect the trend of the granularity curves and assess the operators’ influence factors objectively to some extent. References | Related Articles | Metrics

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Reliability and Sensitivity Design for Indexing Accuracy of End-toothed Disc of Power Servo Turret WANG Xin-gang， CHANG Miao-xin， ZHANG Heng， LYU Chun-mei 2017, 38 (6):  834-838.  DOI: 10.12068/j.issn.1005-3026.2017.06.015 Abstract ( 672 )   HTML   PDF (416KB) ( 753 )   The level of end-toothed disc accuracy has a direct effect on the indexing accuracy of the turret. The indexing error model of turret is proposed based on the analysis of end-toothed disc machining error and then the reliability index and reliability of end-toothed disc are obtained by using the second-order moment method and perturbation method. Using the indexing error model of end-toothed disc， and combing the reliability design theory with sensitivity analysis method， an analytical method for reliability and sensitivity design about end-toothed disc of power servo turret is proposed. The change rule of reliability and sensitivity about the random variable of end-toothed disc is given according to the example， and the effect on the indexing accuracy reliability of end-toothed disc is analyzed when the random variable of end-toothed disc changed. The study shows that， due to the different sensitive degree of design parameters to the indexing accuracy reliability， the sensitive parameters should be optimized so as to improve reliability of the end-toothed disc. Meanwhile， the as-proposed method may provide a theoretical basis for enhancing the reliability of the turret. References | Related Articles | Metrics

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Study on Characteristics of Breaking Rock by Double Edge Central Disc Cutter Under Confining Pressure ZHANG Xu-hui， XIA Yi-min， LIU Jie， TAN Qing 2017, 38 (6):  839-844.  DOI: 10.12068/j.issn.1005-3026.2017.06.016 Abstract ( 608 )   HTML   PDF (1227KB) ( 836 )   In order to study the law of rock-breaking by double edge central disc cutter under different confining pressure， a numerical simulation model was established based on particle discrete element. The change laws of crack propagation and specific energy were analyzed. The results show that， as the double edge central disc cutter invades into the rock， the crack propagation along the vertical direction will be constrained with the increase of confining pressure. The influence of confining pressure on the crack propagation is different between the two cutter edge when the cutter spacing is different. There exists three kinds of breaking modes as the confining pressure and cutter spacing change. The increase of confining pressure will change the breaking mode when cutter spacing is moderate. There exists an optimal cutter spacing and the optimal cutter spacing tends to increase with the increase of confining pressure. The experimental results show that the double edge central disc cutter invaded into rock under different confining pressure is in good agreement with the simulation results in the effect of crack propagation and the change of breaking mode. References | Related Articles | Metrics

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Construction and Parameters Correction of Wheel Virtual Test Bench Based on Measurement ZHANG Zhi-yuan， LIU Yu-mei， YAO Wei-min， CHEN Tao 2017, 38 (6):  845-849.  DOI: 10.12068/j.issn.1005-3026.2017.06.017 Abstract ( 850 )   HTML   PDF (955KB) ( 803 )   In order to improve the wheel performance of a class A car platform， the design process should be fit for the structure durable requirements through the bench tests. A virtual test bench was built to predict rapidly the wheel stress on the bench. The strain test of bench was compared with the simulation considering the effects of various influencing factors such as the bolt preload value， the interaction of contact area of spherical bolt and spoke， weld simulation， assembly surplus between the wheel rim and spokes， loading axis stiffness， stamping process， etc. Different schemes were all analyzed. The size of wheel rim and spokes was scanned. The thickness change of the stamping process to produce spokes was measured. The finite element model parameters were modified to make the simulation strain output more similar to the measured ones， and thus more accurate bench test simulation was established. References | Related Articles | Metrics

Resources & Civil Engineering

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Binding and Strengthening Mechanisms of Organic Binders on the Magnetite Concentrate in Pelletization LU Shuai-shuai， YUAN Zhi-tao， LIU Jiong-tian， LI Li-xia 2017, 38 (6):  849-853.  DOI: 10.12068/j.issn.1005-3026.2017.06.018 Abstract ( 562 )   HTML   PDF (660KB) ( 726 )   Binding effects and mechanisms of organic binders on the magnetite concentrate have been investigated by pelletizing test， FTIR analysis， measurements of zeta potential， contact angle， and binder solution viscosity. Results indicate that wet strengths of pellets with guar gum are the largest， followed by CMC and CMS. Furthermore， it presents a significant positive correlation between the dosage of organic binders and dry pellet strengths. FTIR analysis illustrates that CMS and CMC can adsorb onto the magnetite concentrate by carboxyl methyl and hydroxyl， while the adsorption of guar gum onto the magnetite concentrate is mainly through hydroxyl. Meanwhile， CMS and CMC can increase the negative charge of the magnetite concentrate surface， while guar gum reduces that of the magnetite concentrate. Besides， the adsorption of organic binders on the magnetite concentrate decreases the contact angle and increases the wettability of the magnetite concentrate with water. Results also show that the bigger the viscosity of the binder solution is， the higher the wet strengths of the magnetite concentrate pellets are under the same binder concentration. References | Related Articles | Metrics

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Surrounding Rock Response Pattern of Working Face with High-Intensity Mining Based on Microseismic Monitoring LI Yang,YANG Tian-hong,HOU Xian-gang,WANG Hong 2017, 38 (6):  854-858.  DOI: 10.12068/j.issn.1005-3026.2017.06.019 Abstract ( 1537 )   HTML   PDF (3521KB) ( 1179 )   IMS microseismic monitoring system was employed in Xiaojihan coal mine， a typical high-intensity mining mine in Western China. The spatial monitoring of the whole monitoring area was realized and more comprehensive information of surrounding rock failure was captured. The mine pressure behavior， strata movement， and the stress and deformation around the surrounding rock mass were analyzed based on microseismic monitoring. The results showed that the microseismic events evolved periodically with the continuous mining of 11203 working face， which is closely related to the mining pressure behavior in the working face， and the average periodic weighting length is 23m. The height of “three zones” and the influence range of mining disturbance in the working face could provide help for support design and disaster prevention. References | Related Articles | Metrics

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Effects of Inlet Angle on the Flow Pattern and Pressure Drop of a Hydrocyclone with Gradual Change Section Type Inlet ZHANG Cai-e， WEI De-zhou， CUI Bao-yu， LI Tian-shu 2017, 38 (6):  859-863.  DOI: 10.12068/j.issn.1005-3026.2017.06.020 Abstract ( 688 )   HTML   PDF (979KB) ( 743 )   The effects of inlet angle on the flow pattern and pressure drop in Φ50mm hydrocyclones have been investigated numerically by means of Reynolds stress model (RSM) and volume of fluid multi-phase flow model(VOF). Results show that the tangential velocity increases by increasing the inlet angle， leading to the increase of collection efficiency. Meanwhile， the mass of short-circuit flow can be enhanced and the split ratio can be decreased through increasing the axial velocity and the maximum radial velocity under the vortex finder caused by increasing the inlet angle. Besides， no significant influence on turbulence structure has been found as the inlet angle increases. The air core diameter also increases with the increase of the inlet angle， reducing the effective separation space.The hydrocyclone pressure drop is mainly generated by the pressure losses in the hydrocyclone body (under vortex finder) and in the inlet section. There is an increase in the pressure drop and the power of guiding and accelerating the input flow with increasing of inlet angle， while there is a decrease in energy utilization efficiency.Furthermore， the optimum guiding and accelerating effect is obtained with an inlet angle of 20°. References | Related Articles | Metrics

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Numerical Simulation for Calculating the Tensile Strength and Fracture Toughness Based on Different Grain Sizes YU Miao， ZHU Wan-cheng， YU Yong-jun， YU Qing-lei 2017, 38 (6):  864-868.  DOI: 10.12068/j.issn.1005-3026.2017.06.021 Abstract ( 646 )   HTML   PDF (1505KB) ( 1078 )   Three-point-bending tests on three kinds rock samples of grain sizes 1.02mm(fine grained)， 2.12mm (medium grained) and 3mm(coarse grained) with different notches are numerically performed by RFPA-DIP version to simulate the failure process compared with experimental results in laboratory. A simple fracture model is established， linking fictitious crack to the average aggregate size so that the rock specimen and fictitious crack formation can be considered together. Maximum loads of three-bending-point tests with different initial notches containing different tensile strength and fracture toughness are analyzed. The concept of fractal dimension is introduced to characterize the grain size distribution. It is concluded that the fractal dimension decreases with the increase of grain size， and the rock samples with smaller fractal dimension correspondingly have smaller tensile strength and fracture toughness. References | Related Articles | Metrics

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Different Structure Methods and Application of Background Value in GM(1，1) Model PENG Zhen-bin， ZHANG Chuang， PENG Wen-xiang， WANG Ji-wu 2017, 38 (6):  869-873.  DOI: 10.12068/j.issn.1005-3026.2017.06.022 Abstract ( 1044 )   HTML   PDF (463KB) ( 967 )   The error of GM (1，1) model is mainly from the background value and the initial value， thus the paper puts forward three different construction methods of background value， viz. the method of changing fixed right of background value to the variable right， the method of abstracting the data sequence as index function to construct background value， the method of abstracting the data sequence non homogeneous exponential function to construct background value. And the prediction accuracy of the three methods for background value were compared by setting up GM (1， 1) model with the initial value of X (n). Because the prediction accuracy of future development model for GM (1，1) model is weak， we use metabolism way to establish GM (1， 1) model and continuously optimize and update the model to avoid the large error. The prediction accuracy of GM(1，1) model from the three different construction methods of background value was compared with the engineering examples. The results show that the method of abstracting data sequence as non homogeneous exponential function has a higher prediction precision， and it can provide reference for similar projects. References | Related Articles | Metrics

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Moisture-Heat Migration Laws and Permeability of Compacted Clay Under Temperature Gradient CAI Guang-hua， LU Hai-jun， LIU Song-yu 2017, 38 (6):  874-879.  DOI: 10.12068/j.issn.1005-3026.2017.06.023 Abstract ( 604 )   HTML   PDF (1525KB) ( 867 )   Through the indoor model experiments， the response laws of the moisture-heat migration and permeability of compacted clay were studied under the temperature gradient. The results demonstrated that: the heat transmitted relatively faster at the bottom of clay column than the upper of clay column; the rise of the temperature underwent an obvious delay with the increase of the distance from the heat source; the heat at the bottom facilitated the occurrence of the temperature gradient inside the compacted clay column， which further prompted the moisture migration from the bottom to the top and caused the quick loss of water; with the continuous heating， the temperature gradient inside the compacted clay column underwent a gradual decline， the rate of moisture migration reduced and the moisture content decreased very slowly and tended to be stable. Under the continuous influence of the heat source， the cracking degree of the upper surface was significantly larger than that of the bottom and it was proved to be feasible to test the cracking depth using a tracer. The temperature gradient raised the permeability coefficient of compacted clay to varying degrees. Moreover， the permeability coefficient at both ends of the clay column rose quickly， followed by that in the middle of the clay column. References | Related Articles | Metrics

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Production Scheduling in Underground Mining Using Mixed Integer Programming LIU Xiao-ming， XU Zhi-qiang， CHEN Xin， ZHONG De-yun 2017, 38 (6):  880-885.  DOI: 10.12068/j.issn.1005-3026.2017.06.024 Abstract ( 600 )   HTML   PDF (616KB) ( 745 )   Production scheduling has a profound influence on the overall economic benefits of the mining enterprise， and the manual technology has difficulty to meet the needs of mine. To improve the efficiency and rationality of scheduling， we studied the non-pillar sublevel caving method， and presented a mixed integer programming (MIP) model. This model makes minimum fluctuations of ore grade as the objective function， and it contains the whole process of mining to ensure all procedure could be more reasonable connected. In the test of the production scheduling of the Beiminghe iron mine， the results show that it spent shorter time and the procedure was more reasonable， what′s more， the results are better than the manual method. The study shows that this method can effectively improve the rationality of schedule and make the enterprise get more economic benefits. References | Related Articles | Metrics

Management Science

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Fuzzy Pricing Strategy for Dual Channel Recycling of WEEE Under EPR ZHANG Chuan， YANG Shu-min， LIANG Yan-ming 2017, 38 (6):  886-891.  DOI: 10.12068/j.issn.1005-3026.2017.06.025 Abstract ( 689 )   HTML   PDF (402KB) ( 677 )   For the reversed supply chain system of dual channel recycling whereby the WEEE(waste electrical and electronic equipment) processor recycles itself and simultaneously commits its recycling partners to recycle， the recycling price is viewed as a triangular fuzzy number， and the fuzzy theory and game theory are applied to study the fuzzy recycling pricing of processing enterprises and recycling businesses under the decentralized strategy and centralized strategy. The floating reference point and the floating ranges of their respective recycling prices under the two mentioned cases are given， and the expected fuzzy profits are derived as well. It is shown that the centralized strategy can maximize the systematic profits by setting prices together， compared with the decentralized strategy under the dual channel recycling mode; thus， the centralized strategy tends to improve the systematic efficiency. Finally， an example is given to verify the conclusions. References | Related Articles | Metrics

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A Method of Evidence Conflict Identification Based on the Uncertainty Degree LI Yang， GUO Ya-jun 2017, 38 (6):  892-897.  DOI: 10.12068/j.issn.1005-3026.2017.06.026 Abstract ( 535 )   HTML   PDF (844KB) ( 748 )   This article defines the uncertainty degree of describing the features of evidence itself starting from the highly conflict evidence’s constraints on the application D - S evidence theory， and aiming at the existing problem of several common conflict measurement method. The connotation of evidence conflict is extended from inconsistency between the evidences to both inside and outside of evidence. Evidence conflict multi-measurement is given based on uncertainty， and the conflict processing method of maximum difference degree is put forward in order to enhance the effect of the conflict recognition. Validation analysis showed that the measurement method in this paper can effectively represent conflict degree between evidences; the processing of maximum conflict difference degree achieves significance of evidence conflict identification， which has good universality and effectiveness in evidence conflict recognition of complex systems. References | Related Articles | Metrics

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Optimal Strategy in Service Supply Chain Considering Social Responsibility and Quality Effort XING Peng， ZHANG Cui-hua， LI Chun-yu 2017, 38 (6):  898-902.  DOI: 10.12068/j.issn.1005-3026.2017.06.027 Abstract ( 660 )   HTML   PDF (649KB) ( 766 )   Considering the corporate social responsibility of service integrators and service quality effort of service providers， optimal strategy in service supply chain is investigated. Utility functions of service integrators and service providers with behavior characters are established based on the quantization of corporate social responsibility and service quality effort. Models are optimized to maximize members’ utilities; thereby， optimal strategy of corporate social responsibility， service quality effort and price are obtained under different constraints. The numerical simulation shows service supply chain members’ optimal utilities have positive correlation with the upper limit of integrators’ social responsibility and providers’ investment budget of service quality effort in most situations. Secondly， in order to ensure the maximum utility， integrators should improve corporate social responsibility and select providers with higher quality effort to collaborate. Finally， to obtain the optimal utility， providers should choose integrators with better corporate social responsibility to collaborate. However， providers should not increase enterprises’ utility blindly by enhancing the investment budget of quality effort. References | Related Articles | Metrics

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Managers Dynamic Incentive Model Considering Dismissal Tendency and Turnover Intention SUN Shi-min， YANG Huan， LIU Yi-tong， ZHANG Han-nan 2017, 38 (6):  903-908.  DOI: 10.12068/j.issn.1005-3026.2017.06.028 Abstract ( 598 )   HTML   PDF (531KB) ( 623 )   Considering turnover intention and dismissal tendency， managers’ two-stage dynamic incentive model was designed in which managers’ expected utility and enterprises’ expected return were determined according to the three possibilities and probabilities of re-election， compensation turnover and non-compensation turnover. Five conclusions were drawn as follows. Firstly， the greater a manager’s turnover intention is， the lower his effort is and the higher his requirement for the performance share ratio will be. Secondly， when a manager gets more dismissal payment than the increase of basic salary in the next period while he provides the same effort， the more the dismissal intention is， and the greater the manager’s effort is， the lower his requirement for the performance share ratio will be. Thirdly， the dynamic basic salary system can help to improve managers’ effort. Fourthly， the higher the proportion of monopolistic surplus is， the lower the manager’s effort will be. Finally， the greater the performance share ratio and the non-monetary utility sensitivity are， the higher the manager’s effort will be. References | Related Articles | Metrics

Mathematics

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Iterative Solutions to Sylvester Matrix Equations SHAO Xin-hui， PENG Cheng 2017, 38 (6):  909-912.  DOI: 10.12068/j.issn.1005-3026.2017.06.029 Abstract ( 581 )   HTML   PDF (387KB) ( 1063 )   The gradient-based iterative solutions to Sylvester matrix equations are given. By introducing a relaxation parameter and applying the hierarchical identification principle， an iterative algorithm is constructed to solve Sylvester matrix equations. Convergence analysis indicates that the iterative solutions converge with the exact solutions to any initial value under certain assumptions. Numerical examples are given to testify the efficiency of the proposed method. References | Related Articles | Metrics