Loading...

Archive

    For Selected: Toggle Thumbnails
    Information & Control
    A Fault Identification Method for Distribution Lines Based on Atomic Energy Entropy and CSM
    NING Yi, WANG Da-zhi, JIANG Xue-chen, ZHANG Cui-ling
    2017, 38 (1):  1-5.  DOI: 10.12068/j.issn.1005-3026.2017.01.001
    Abstract ( 745 )   HTML   PDF (616KB) ( 780 )  
    :In order to solve the problem of fault classification on distribution lines, a method was proposed in which atomic energy entropy was combined with continuous string matching (CSM). The fault transient feature was analyzed, the dominant atom and the secondary one of fault transient signal were achieved by atom decomposition method, and the secondary one was used to supplement fault information. Atomic energy entropy of each atom was regarded as the fault characteristic value, representing fault feature more completely. Applying CSM fault classification method could save the time spending on selection and optimization of processing parameters in some smart fault identification method, through the establishment of encoding rules, fault features were encoded, and then the fault type was finally confirmed by searching the encoded fault library. A case study of system model showed that the proposed method is feasible and efficient.
    References | Related Articles | Metrics
    Phase Estimation Method for Power System Based on Complex Adaptive Neural Network
    LI Yun-lu, WANG Da-zhi, NING Yi, HUI Nan-mu
    2017, 38 (1):  6-10.  DOI: 10.12068/j.issn.1005-3026.2017.01.002
    Abstract ( 734 )   HTML   PDF (582KB) ( 812 )  
    Aiming at the difficulty of grid phase detection under non-ideal voltage caused by unbalanced voltage and frequency fluctuation, a phase estimation method was proposed for power system based on complex adaptive neural network. On the basis of neural network model of non-ideal grid voltage, the weight update method of complex least mean squares to the process of weight update procedure of neural network was introduced. Then the weights of neural network were used to calculate the phase. To trace the frequency of grid, a frequency tracing unit was designed and it was proved to be convergent. The simulation and experiment results demonstrate that the proposed method is able to estimate the phase rapidly and precisely under non-ideal voltage conditions.
    References | Related Articles | Metrics
    Prediction for Dynamic Fluid Level of Oil Well Based on GPR with AFSA Optimized Combined Kernel Function
    LI Xiang-yu, GAO Xian-wen, LI Kun, HOU Yan-bin
    2017, 38 (1):  11-15.  DOI: 10.12068/j.issn.1005-3026.2017.01.003
    Abstract ( 864 )   HTML   PDF (2388KB) ( 910 )  
    The dynamic fluid level (DFL) of an oil well is usually measured onsite by using the acoustic method. This method, however, has its limitation in determining the real-time DFL. Considering that Gaussian process regression (GPR) with single kernel function cannot significantly improve the prediction accuracy and generalization ability, a dynamic GPR for DFL with the combined kernel function optimized by artificial fish-swarm algorithm (AFSA) was proposed. The polynomial function, liner function and radial basis function were used to construct the combined kernel function of GPR in order to improve the generalization ability. The AFSA was used to optimize parameters of the combined kernel function in order to improve the prediction accuracy. The fast Fourier transform (FFT) and kernel principal analysis (KPCA) were used to extract nonlinear features of data in the time and frequency domain as the input variables of the model. The oil field application shows the validity of the proposed method.
    References | Related Articles | Metrics
    Optimization Model for Locating Continuous Exclusive Bus Lanes
    LU Xiao-lin, YU Jie, ZOU Nan, LIU Hao-de
    2017, 38 (1):  16-21.  DOI: 10.12068/j.issn.1005-3026.2017.01.004
    Abstract ( 804 )   HTML   PDF (645KB) ( 983 )  
    Aiming at the limitation of disperse exclusive lane locating, a two level optimization model was presented for the location of the continuous exclusive bus lane based on public transit corridor. Realistic conditions, planning and construction practice of exclusive bus lanes locations were explicitly taken into account in the proposed model. The upper-level of the proposed model was the locating model to minimize the total travel time of the whole road network, and the lower-level was the allocation model of car and bus to minimize the generalized travel cost. The genetic algorithm based on the method of successive averages was developed to solve the problem. The test of the effectiveness and practicability of the model and the sensitivity analysis of the key parameters were carried out through a case study, and the continuous exclusive bus lane locations have more superiority than discrete exclusive bus lane locations.
    References | Related Articles | Metrics
    RDF Keyword Search by the Condensed Entity Summary Graph
    LIN Xiao-qing, MA Zong-min
    2017, 38 (1):  22-26.  DOI: 10.12068/j.issn.1005-3026.2017.01.005
    Abstract ( 629 )   HTML   PDF (626KB) ( 719 )  
    A method of translating keyword queries to SPARQL queries was presented to implement RDF (resource description framework) keyword search. Firstly, a condensed entity summary was constructed according to connections of RDF data. Then, keywords were located on the designated nodes of the summary graph by the OPS (object predicate subject) index. Top-k subgraphs connecting all keyword entities would be found by a bidirectional search algorithm. Finally, SPARQL queries were obtained by incorporating inter-entity relationships of top-k subgraphs, keywords and their properties, and SPARQL queries were executed by a SPARQL search engine. The experimental results show that a faster response time and a higher accuracy than the existing ones are achieved.
    References | Related Articles | Metrics
    A Novel Swing Trajectory Recognition Method for Badminton Racket
    CUI E-nuo,CHEN Xing-chi, ZHAO Hai, LI Han
    2017, 38 (1):  27-31.  DOI: 10.12068/j.issn.1005-3026.2017.01.006
    Abstract ( 1223 )   HTML   PDF (655KB) ( 1752 )  
    A novel trajectory recognition method (TRM) using multi-sensor fusion was proposed to extract the motion trajectory of badminton racket more accurately. The smart device was placed in the bottom of the handle of the racket, which was composed of accelerometer, magnetometer and gyroscope. Firstly, the date of gyroscope was optimized by accelerometer and magnetometer. By combining gyroscope error, the attitude angle of trajectory could be obtained using TRM. Then the speed and the displacement were calculated by frequency domain integral of acceleration data. The accumulated error of frequency domain integral is removed by the least squares fitting method.Finally, the trajectory was identified by attitude angle, the speed and the displacement. Multiple experimental results show that the validity of TRM is great. Compared with the traditional time domain integral trajectory recognition method, the identification accuracy of TRM is higher. TRM can recognize the trajectory of badminton racket more accurately.
    References | Related Articles | Metrics
    Feasibility Analysis on Pulse Rate Variability as an Estimate of Heart Rate Variability
    XU Li-sheng, ZHOU Shu-ran, YAO Yang, QI Lin
    2017, 38 (1):  31-35.  DOI: 10.12068/j.issn.1005-3026.2017.01.007
    Abstract ( 1070 )   HTML   PDF (342KB) ( 1415 )  
    Whether pulse rate variability (PRV) can be a surrogate of heart rate variability (HRV) was investigated, and their quantitative relationship was also studied. Three groups (healthy adolescents, old people and patients with cardiovascular diseases) were enrolled. Each group has 25 subjects and their pulse waves and ECG data were acquired simultaneously. Furthermore, the differences and relationships between them were analyzed after comparing some characteristic parameters of HRV and PRV in the time domain, frequency domain and nonlinear domain. The results show that HRV and PRV are not exactly the same, but there are some agreements in healthy adolescent group for all the parameters (SDNN, RMSSD, PNN50, HF, LF, SD1, SD2, α1, α2, SE, CD and AE; Ratio<0.2), which, in a certain extent, can be replaced. There are insufficient agreements for other parameters (old people: PNN50, RMSSD, LF and HF; Patients: PNN50, RMSSD, LF, HF, SD1 and SE; Ratio≥0.2) while there are agreements in old people group and patients with cardiovascular disease group for some parameters (old people: SDNN, SD1, SD2, SE, α1, α2, CD, SE and AE; patients: SDNN, SD2, α1, α2, CD and AE; Ratio<0.2), so HRV cannot be replaced with PRV.
    References | Related Articles | Metrics
    Materials & Metallurgy
    Simulation Study on Microstructure Evolution of Low Carbon Si-Mn Steel During Direct Quenching and Partitioning
    LI Yun-jie, KANG Jian, YUAN Guo, WANG Guo-dong
    2017, 38 (1):  36-41.  DOI: 10.12068/j.issn.1005-3026.2017.01.008
    Abstract ( 843 )   HTML   PDF (1922KB) ( 824 )  
    Effects of deformation temperature and partitioning time on microstructure evolution of low carbon Si-Mn steel during direct quenching-partitioning process were investigated. The volume fraction of retained austenite and the carbon concentration in retained austenite were quantitatively studied. The results showed that the typical microstructure of Q&P steel consists of a small amount of retained austenite, ferrite and martensite containing lath martensite and twin martensite. With increase of the partitioning time, the microstructure shows a tempered transformation tendency. When deformation temperature is 950℃and 880℃, the volume fraction of retained austenite decreases after the first increase and reaches the maximum, 9.1%, 10.1%, respectively at the partitioning time of 150s. When deformation temperature is 820℃, the volume fraction of retained austenite increases up to 11.9% because of proeutectoid ferrite. And the carbon concentration in austenite is relatively lower.
    References | Related Articles | Metrics
    Effects of Extrusion Ratio on Microstructure and Mechanical Property of ZA15 Zn Alloy Extruded at Lower Temperature
    SUN Shi-neng, WANG Li-qing, REN Yu-ping, QIN Gao-wu
    2017, 38 (1):  42-45.  DOI: 10.12068/j.issn.1005-3026.2017.01.009
    Abstract ( 772 )   HTML   PDF (1737KB) ( 1005 )  
    The effects of extrusion ratio on microstructures and mechanical properties of ZA15 Zn alloy extruded at 150℃ were investigated by microscopy and tensile test. The results showed that the tensile strength of the extruded ZA15 Zn alloy is improved with increasing of the extrusion ratio, but all are lower than 150MPa. And the tensile elongation remains about 160%~180%, which is the feature of room temperature superplasticity. This is mainly because the lamellar eutectoid microstructure composed of α+η phases formed by heat treatment is transformed into one consisting of the η matrix and small α phase particle with dispersive distribution through plastic deformation. It implies that the room temperature superplasticity can be obtained in the ZA15 Zn alloy manufactured by the common extrusion at lower temperatures, and the mechanical properties can be satisfied with the new standard of the ZA15 Zn alloy wire used to thermal spraying industry.
    References | Related Articles | Metrics
    Influence of Microstructure on Mechanical Property of GH4720Li Alloy
    KAN Zhi, DU Lin-xiu , HU Jun , WENG Lei
    2017, 38 (1):  46-50.  DOI: 10.12068/j.issn.1005-3026.2017.01.010
    Abstract ( 985 )   HTML   PDF (2237KB) ( 1076 )  
    The microstructures of GH4720Li alloy samples which were cut from GH4720Li alloy bar including forging and heat treatment states were observed, and the phase compositions of primary γ′ was measured via energy spectrum analysis. The tensile properties of the samples through heat treatment were tested at 20 and 650℃. The results indicated that the quantity of primary γ′ of GH4720Li alloy decreases from the edge to the center of the bar while the size of primary γ′ increases gradually. The influence of heat treatment on the quantity and distribution of primary γ′ is not noticeable, but the influence of heat treatment on the quantity and distribution of secondary γ′ is noticeable. The tensile strength of GH4720Li alloy increases at the first and decreases in the end from the edge to the center of the bar, but the plasticity of alloy increases gradually. The quantity and plasticity of primary γ′ are the chief factors influencing the alloy plasticity. The phase boundary of primary γ′-γ is the crack source in the tensile tests. As the precipitation temperature rises, the plasticity of primary γ′ increase, the element contents of aluminum and titanium in the primary γ′ decrease, but the element contents of chromium, cobalt, molybdenum and tungsten in the primary γ′ increase.
    References | Related Articles | Metrics
    Reaction Process Analysis of SiO2 and Zn2SiO4 Roasting with Molten NaOH
    SHEN Xiao-yi, JIA Chao-hang, LI Hao, WU Kang-long
    2017, 38 (1):  51-56.  DOI: 10.12068/j.issn.1005-3026.2017.01.011
    Abstract ( 697 )   HTML   PDF (1250KB) ( 1036 )  
    Employing homemade SiO2 and analytic Zn2SiO4 as raw materials and NaOH as reaction medium, the influences of reaction temperature, molar ratio of NaOH to SiO2 and reaction time on the extraction ratio of silica were investigated. The appropriate reaction conditions were obtained as reaction temperature of 450℃, molar ratio of NaOH to SiO2 of 2.4∶1 and reaction time of 60min. Silica reacted with NaOH to form Na2SiO3 at first and then was transformed into Na4SiO4 along with temperature rising. The appropriate reaction conditions of Zn2SiO4 roasting were reaction temperature of 500℃, molar ratio of NaOH to Zn2SiO4 of 20∶1 and reaction time of 150min. Na2ZnSiO4 and Na2ZnO2 were formed when Zn2SiO4 reacted with NaOH. Silicon oxygen tetrahedron reacted with NaOH to form Na2SiO3 when the roasting temperature reached 350℃, and then Na2SiO3 was transformed into Na4SiO4.
    References | Related Articles | Metrics
    Experimental Study of Bubble Size Distribution in Continuous Casting Mold
    LIU Zhong-qiu, LI Lin-min, LI Bao-kuan
    2017, 38 (1):  57-61.  DOI: 10.12068/j.issn.1005-3026.2017.01.012
    Abstract ( 629 )   HTML   PDF (1656KB) ( 789 )  
    In order to obtain the bubble size distribution in the mold, a water model system was developed with air blowing through a circumferential inlet chamber made of specially-coated mullite porous brick, which is used as the actual upper nozzle. The transient bubble distributions in the mold were captured by a high-speed video camera under a laser light beam. Then, the location and size of bubbles were measured using the image analysis software of ImageJ. The results show that the average bubble size increases with increasing the water flow rate and SEN immersion depth, decreases with increasing the gas blowing rate and nozzle port angle. The initial bubble size obtained from the mullite brick is small and uniform. The bubble size along the horizontal direction of wide wall increases first and then decreases. With the increase of water flow rate, the bubble distribution is more dispersed. With the increase of gas blowing rate, there is no obvious difference for the bubble distribution; however, the bubble size was increased.
    References | Related Articles | Metrics
    Study of CaS Formation Mechanism in X80 Pipeline Steel
    XU Guang, JIANG Zhou-hua, LI Yang, ZHANG Cong
    2017, 38 (1):  62-66.  DOI: 10.12068/j.issn.1005-3026.2017.01.013
    Abstract ( 654 )   HTML   PDF (2576KB) ( 860 )  
    The equilibrium relationships of Ca-Al, Al-S and Ca-S were determined by thermodynamic calculation. The regional distribution of calcium aluminates was established on the basis of fixed sulfur content with the relationship of Ca-Al and Al-S as reference. The results indicate that liquid calcium aluminates can be generated with wCa▲T>0.001 7%~0.002 7% when wAl▲T in X80 pipeline steel is 0.03%~0.06%, and Ca and S can form CaS by direct reaction when wS>0.001 8%~0.002 8% correspondingly. The modification degree of Al2O3 inclusions has a great effect on the generation of CaS. With the increase of the S content in molten steel, the possibility of CaS formation at the edge of inclusion will increase. The agreement between thermodynamic calculation and actual production is proved by industrial test. Two kinds of CaS with different forming modes were found, and thus the rationality of predicted generating modes of CaS was proved.
    References | Related Articles | Metrics
    Preparation of Chromium Oxide Product from Chromium Residue
    TIAN Lei, ZHANG Ting-an, LIU Yan, LYU Guo-zhi
    2017, 38 (1):  67-71.  DOI: 10.12068/j.issn.1005-3026.2017.01.014
    Abstract ( 756 )   HTML   PDF (512KB) ( 960 )  
    The harmless treatment of chromium hydroxide residue was studied. The effects of NaOH concentration, liquid to solid mass ratio, leaching temperature, stirring rate and holding time on the leaching rate of aluminum were investigated. The results show that the removal rate of aluminum from chromium residue can reach 92.69% when the temperature was 100℃, the NaOH concentration was 150g/L, the liquid to solid ratio was 7∶1, the stirring rate was 400 r/min and the holding time was 3.5h. After washing with water, the leaching residue was calcined at 950℃ for 90 min to produce chromium hemitrioxide, and its content reached 97.23%. The chromium hemitrioxide is green and suitable for industrial use according to the measurement with CIE L*a*b*colour space.
    References | Related Articles | Metrics
    Crystallization Fraction of Continuous Casting Mold Fluxes Using TEC Method
    YU Liang, WEN Guang-hua, TANG Ping, YANG Chang-lin
    2017, 38 (1):  71-75.  DOI: 10.12068/j.issn.1005-3026.2017.01.015
    Abstract ( 590 )   HTML   PDF (596KB) ( 771 )  
    The solid slag film and quenched slag of a high-Al steels mold flux with different Li2O contents were obtained by a HF-200 heat flux simulator. Through grounding, sieving and compacting, the size of the obtained specimen can meet the requirement of TEC (thermal expansion curve) measurement. The crystallization fraction and the reproducibility of data were investigated by the TEC method and proved by the DSC (differential scanning calorimeter) method. The results show that the TEC method can be employed to study the crystallization fraction of mold fluxes. The method is accurate, reliable and reproducible, with maximum difference of 2.7%. The results obtained by TEC agree well with DSC measurements. The temperature of starting to shrink on TEC curve is in accordance with the glass transition temperature on DSC curve, and is lower than the peak temperature of DSC curve. Compared with DSC method, the TEC method does not lead to uncertainty in the determination of the area due to the baseline shift in DSC, and is thus a better method to study the crystallization of mold fluxes.
    References | Related Articles | Metrics
    Mechanical Engineering
    Self-Synchronous Process Analysis and Experiment Investigation of Vibration System Driven by Two Motors
    CHEN Xiao-zhe, KONG Xiang-xi, DOU Jing-xin, WEN Bang-chun
    2017, 38 (1):  76-80.  DOI: 10.12068/j.issn.1005-3026.2017.01.016
    Abstract ( 620 )   HTML   PDF (744KB) ( 910 )  
    The self-synchronous process of a vibration system driven by two exciters rotating oppositely was investigated by simulation and experiment. The rotational velocities of the two motors and phase differences between the two exciters were chosen as indexes to represent for the self-synchronous process. By comparing the changes of the phase difference, the most important influence factor of the phase difference is motor, and the second is exciter, while the last one is the vibration rigid. The simulation and experimental results show that the initial phase difference between the two exciters and the initial velocities of the two motors have no effect on the self-synchronization. When the synchronous condition is satisfied, the two motors can achieve synchronous motion with different power supply frequencies. When change the masses of the two exciters, the phase of the bigger mass lags behind the smaller one. When the distances between the rotary centers of the two exciters and the mass center of the vibration rigid body are different, the phase of the bigger distance lags behind the smaller one. The phase difference can be reduced by adjusting the power supply frequency, which are caused by motor parameters, the mass of exciters, and the motor installation position and so on.
    References | Related Articles | Metrics
    Reliability Sensitivity Analysis and Optimization Design on Tractive Drive System of Shearer Loader
    ZHOU Di, ZHANG Xu-fang, ZHANG Yi-min
    2017, 38 (1):  81-85.  DOI: 10.12068/j.issn.1005-3026.2017.01.017
    Abstract ( 777 )   HTML   PDF (592KB) ( 910 )  
    Traction unit is an important dynamic transmission system of a shearer loader. Considering the nonlinear backlash and time-varying mesh stiffness, the dynamic model was established for the tractive transmission system of MG300/700-WD shearer loader. Based on the high-order stochastic response method, an explicit relationship between the parameters of traction unit and the maximum contact stress was built. Indexes of reliability sensitivity were calculated to analyze the system performance. The maximal reliability model and minimal space model were proposed to optimize the traction unit in shearer loader. The research results show that the second planetary gear system has a great effect on the reliability of traction unit and the parameters of sun gear are more sensitive than those of planet gear. The optimization models can elevate the system reliability and can decrease the indexes of reliability sensitivity in the area of high structural strength.
    References | Related Articles | Metrics
    A Novel Approach to Compute the Frequency Reliability and Reliability Sensitivity for Complex Mechanical Structures
    MA Tian-zheng, LYU Hao, ZHANG Yi-min
    2017, 38 (1):  86-90.  DOI: 10.12068/j.issn.1005-3026.2017.01.018
    Abstract ( 598 )   HTML   PDF (571KB) ( 897 )  
    For the frequency response of complex mechanical structures with random parameters, the frequency reliability was defined and an efficient method to compute the frequency reliability and reliability sensitivity was proposed. The stochastic response surface was employed to approximate the relationship between input variables and natural frequency. Dimension reduction integral was utilized to compute the coefficients of the stochastic response surface expansion. In order to alleviate the computational burden of structural reanalysis, a kind of model order reduction technique was applied. The AFOSM (advanced first order second moment) method was utilized to evaluate the frequency reliability and the reliability sensitivity was obtained by the Monte Carlo simulation. The numerical examples demonstrate the efficiency and accuracy of the method for complex structures.
    References | Related Articles | Metrics
    Deformation of Fiber-Metal Laminates Under Uniaxial Tensile Loading
    TONG An-shi, XIE Li-yang, LIU Jian-zhong, BAI En-jun
    2017, 38 (1):  91-94.  DOI: 10.12068/j.issn.1005-3026.2017.01.019
    Abstract ( 703 )   HTML   PDF (2229KB) ( 847 )  
    In order to find the deformation behavior and boundary effect of fiber-metal laminate (FML) under uniaxial tensile loading, mechanical tests were carried out on GLARE2-3/2, GLARE3-3/2 and GLARE6-3/2 laminates. A new method of digital image correlation was introduced to record the surface strain of the GLARE laminate samples during loading. The stress-strain curves, strain cloud chart and strain-loading time curves show that the deformation of GLARE2-3/2 laminates is uniform,without obvious boundary effects; the GLARE3-3/2 laminates have instantaneous performance degradation and boundary effect, and the GLARE6-3/2 laminates have two performance degradation and the boundary effect is opposite to that of GLARE3-3/2 laminates.
    References | Related Articles | Metrics
    Investigation on Ultrasonic Vibration Assisted Turning of Ni-Based Superalloy and Al-Mg Alloy
    XU Ying-shuai, ZOU Ping, WANG Wei, YANG Xu-lei
    2017, 38 (1):  95-100.  DOI: 10.12068/j.issn.1005-3026.2017.01.020
    Abstract ( 731 )   HTML   PDF (1368KB) ( 885 )  
    For the machinability difficulty of GH4169 Ni-based superalloy and 5A06 Al-Mg alloy as well as the high demands of machined surface quality and machining precision, the ultrasonic vibration assisted turning machining system was designed utilizing the method of ultrasonic vibration, which proceeded with cutting principle and machining technology. The contrast test was conducted to compare ultrasonic vibration assisted turning with conventional turning for these two alloy materials. The results indicate that the technological parameters have obvious effect on the surface roughness, surface topography and chip morphology of machined workpiece when ultrasonic vibration assisted turning of Ni-based superalloy and Al-Mg alloy is conducted. Choosing reasonable technological parameters can promote efficiently the processing quality, and enable the machining effects of ultrasonic vibration assisted turning to be superior to that of conventional turning.
    References | Related Articles | Metrics
    Characteristics of Dry Grinding Surface Hardening Layer Under Pre-stressed Loading Conditions
    WANG Ren-sheng, DONG Le, MA Liang, XIU Shi-chao
    2017, 38 (1):  101-104.  DOI: 10.12068/j.issn.1005-3026.2017.01.021
    Abstract ( 616 )   HTML   PDF (1279KB) ( 701 )  
    The surface grinding hardening of non-quenched and tempered 45# steel specimens under different pre-stressed loading conditions was carried out by using the pre-stressed hardening grinding process (PSHG). The metallographic structures of the specimens surface under different grinding depths and feed rates were observed, and the thickness of the hardening layer of the specimens and the change of its metallographic structure were measured and analyzed under different pre-stressed conditions. The influence of pre-stress on the thickness of the hardening layer was obtained by measuring the hardness of the specimens section. It was shown that the pre-stressed hardening grinding can make the workpiece surface become a hardening layer, and the larger grinding depth and the lower feed rate will be beneficial to the phase transformation hardening and plastic deformation of the surface layer.
    References | Related Articles | Metrics
    Cutting Load Characteristics of a Single Cutter on the Pre-cutting Machine
    XIA Yi-min, WU Cai-zhang, TIAN Ze-yu, ZHAO Hong-chao
    2017, 38 (1):  105-110.  DOI: 10.12068/j.issn.1005-3026.2017.01.022
    Abstract ( 628 )   HTML   PDF (1084KB) ( 712 )  
    In order to study the cutting load characteristics of cutters on the pre-cutting machine in the grooving process, a load calculation model of a single cutter’s horizontal cutting was established and its rock-cutting process was simulated using LS-DYNA to analyze the influence of different cutting depths as well as varied blade angles on the horizontal load. The results showed that the horizontal cutting load is much greater than the vertical cutting load, and the horizontal load increases as the cutting depth increases. In condition of the same cutting depth, the horizontal load increases with the increment of blade angles, and it was found that when the blade angle increases from 80°to 125°, the average magnitude of horizontal load at different depths increases by 30.7%. Generally, with the increment of the cutter’s blade angle, the specific energy increases firstly and then remains stable. The rock-cutting efficiency reaches its maximum status when the blade angle is 110°,and the specific energy decreases with the increment of cutting depths.
    References | Related Articles | Metrics
    Method for Determining Design Time Based on Difficulty Coefficient of Product Design
    GU Meng-yao, CHEN You-ling, DU Xuan-xuan
    2017, 38 (1):  111-115.  DOI: 10.12068/j.issn.1005-3026.2017.01.023
    Abstract ( 719 )   HTML   PDF (693KB) ( 932 )  
    Aiming at forecasting design time quickly and accurately, the relationship between product design difficulty and design time was researched, and a method based on the difficulty coefficient of product design was proposed. First of all, by analyzing the difficulty representation modes of product design and combining the entropy evaluation method and expert weights method based on the correlation coefficient and standard deviation,the difficulty coefficient model of product design was established. Meanwhile, based on the enterprise database and coding technology, the relationship function between difficulty coefficient and design time of product design was determined with Matlab, and then the design time estimation model based on the difficulty coefficient of product design was established. Finally, the proposed method was verified to be applicable and available by an example and comparative experiments with existing algorithms. The results showed that the proposed method has better practicability and accuracy for design time estimation.
    References | Related Articles | Metrics
    Resources & Civil Engineering
    Development of Three-Dimensional Dynamic Visualization System for Laneway Convergence Monitoring
    WANG Yun-sen, LI Yuan-hui, XU Shuai
    2017, 38 (1):  116-120.  DOI: 10.12068/j.issn.1005-3026.2017.01.024
    Abstract ( 823 )   HTML   PDF (775KB) ( 861 )  
    Combined with the advantages of traditional laneway convergence measure instrument and 3D laser scanning, a method for obtaining and presenting laneway convergence via 3D visualization was proposed. This method utilizes laser scanning point cloud data from laneway to reconstruct shell model by triangulation. The inverse distance weighted interpolation algorithm is then employed to compute the convergence of the laneway periphery. A parabolic nonlinear enhancement algorithm is further developed based on the one-to-one correspondence between the convergence and the color index, in order to highlight the more obvious convergence within the study area. The whole system was developed using VS2010 and HOOPS, which realizes the dynamic visualization of the 3D convergence contour obtained from surface monitoring. The application of the developed system in the Tiedanshan mine clearly and vividly showed the dangerous area and deformation process of laneway which satisfied the engineers′ requirement for direct presentation and real-time visualization of monitoring data.
    References | Related Articles | Metrics
    Stochastic Spatial Characterization of Structural Plane Occurrence in Rockmass
    WANG Shu-hong, ZHANG Zi-shan, WANG Cun-gen, ZHANG Feng-chun
    2017, 38 (1):  121-125.  DOI: 10.12068/j.issn.1005-3026.2017.01.025
    Abstract ( 800 )   HTML   PDF (2141KB) ( 1217 )  
    Based on different probability distribution functions, a stochastic planes simulation is applied in engineering rockmass. Three different probability distribution density functions: dual average density distribution, dual normal distribution and Fisher distribution are used to generate the stochastic structural planes. Meanwhile, a back analysis method is applied to acquire the distribution parameters based on spatial attitude. By inputting the data of deterministic structral planes and stochastic structural plane of a rock slope project in Liaoning Province, the slope modeling can be built and the key blocks can be identified by GeoSMA-3D(geotechnical structure and model analysis-3D). Then a discreteness index is put forward to evaluate the effectiveness and difference of different stochastic structural plane simulations. The results show that key blocks’ volume will increase when the discreteness index becomes smaller within a certain range.
    References | Related Articles | Metrics
    Research on Non-linear Shear Strength Criterion for Layered Rock Mass with Micro-discontinuity
    YANG Jun-sheng, ZHANG Cong, XIAO Xiao-wen, ZHANG Xue-min
    2017, 38 (1):  126-131.  DOI: 10.12068/j.issn.1005-3026.2017.01.026
    Abstract ( 633 )   HTML   PDF (1418KB) ( 752 )  
    Tri-axial compression tests are carried out on the layered sandstone specimens taken from the QEX Tunnel located in Xiangxi of Hunan. The results show that the strength of the rock is obviously anisotropic and there are two distinct failure modes, i.e., one is the failure caused by sliding along the discontinuity and the other is non-sliding failure mode in which fracturing of rock material, fracturing across the discontinuity and the mixed mode of the above. Then a non-linear failure criterion for the layered sandstone is proposed to reflect different failure modes using different methods. Performance of the failure criterion is tested for validation against tri-axial compression tests data for the layered sandstone specimens. It shows that predicted values are in good agreement with experimental test data. The applicability of the failure criterion is also examined using the published experimental data of various types of layered rock mass.
    References | Related Articles | Metrics
    Pore Size Distribution of Expansive Soil of the Subgrade Slope in Yanbian Region, Jilin Province
    BAO Shuo-chao, WANG Qing, CHEN Jian-ping, BAO Xin-hua
    2017, 38 (1):  132-137.  DOI: 10.12068/j.issn.1005-3026.2017.01.027
    Abstract ( 681 )   HTML   PDF (460KB) ( 723 )  
    This research aims at the stability of expansive soil which were collected from the subgrade slope of expansive soil in Yanbian region of Jilin Province. The physicochemical property, soil grain, mineral composition and the expansion property of the specimen were tested. The pore structure characteristics were studied using mercury injection experiment. Furthermore, the soil pores were divided into four size intervals, i.e., big pores, moderate pores, micro-pores and ultra-micro pores by using fractal geometry theory. The study indicated that five specimens were identified as slightly-expansive soil by expansibility testing. Pore sizes of the high expansive soil mainly fall in between micro-pores and ultra-micro pores, while pore sizes of the weak expansive soil mainly fall in between big and moderate pores.
    References | Related Articles | Metrics
    Management Science
    Profit Sharing Contract Model for Supply Chain of Uncertainties Under Risk Aversion
    ZHU Bao-lin, QI Ya-ping, JI Shou-feng, QIU Ruo-zhen
    2017, 38 (1):  138-142.  DOI: 10.12068/j.issn.1005-3026.2017.01.028
    Abstract ( 688 )   HTML   PDF (476KB) ( 776 )  
    For a three-stage supply chain system which consists of single supplier with yield uncertainty, manufacturer with yield certainty and retailer with demand uncertainty under retailer risk aversion, a profit sharing contract model based on CVaR principles was established. The characteristics of centralization, decentralization and risk aversion model were compared, and a profit sharing contract coordination mechanism was proposed. The impact of yield and demand uncertainties on decision and expected profit was analyzed. Finally, the validity of contract coordination was presented by a numerical example. The results showed that the expected profit of decentralization can be proven to be at the level of that of centralization decision by the profit sharing contract. The goal of coordination is ultimately achieved for the three-stage supply chain system.
    References | Related Articles | Metrics
    Product Selection Methods Based on Online Reviews
    LIANG Xia, JIANG Yan-ping, GAO Meng
    2017, 38 (1):  143-147.  DOI: 10.12068/j.issn.1005-3026.2017.01.029
    Abstract ( 717 )   HTML   PDF (362KB) ( 1009 )  
    With the advent of the big data era, the scale of e-commerce platforms has expanded rapidly and consumers need more efficient product selection methods, which would help make decisions quickly in the massive kinds and a number of products. Therefore, a method of product selection based on online reviews is proposed. First, the utility values of the online reviews are calculated. By extracting the product attributes, the attribute set for product selection is obtained. Considering the utility values of the online reviews, the weight vector of attributes is determined. Second, by analyzing the sentiment words, consumers’ sentiment preferences are expressed in the format of probability distribution about sentiment levels. Based on the principle of stochastic dominance, the dominance relationships of any pairwise products on each attribute are determined. Third, by using PROMETHEE II, the ranking result of alternative products is obtained. Finally, an example of product selection is given to illustrate the feasibility and practicability of the proposed method.
    References | Related Articles | Metrics
    Empirical Research on the Dependency of the CSI 300 Index Futures Market and Spot Market
    YUAN Ying, WANG Meng-di, ZHANG Tong-hui, FAN Xiao-qian
    2017, 38 (1):  148-152.  DOI: 10.12068/j.issn.1005-3026.2017.01.030
    Abstract ( 610 )   HTML   PDF (511KB) ( 772 )  
    Considering the financial markets’characteristics of the cross-correlation in the case of nonlinearity and non-normality, and from the perspective of complexity theory, the cross-correlation statistic test, detrended cross-correlation analysis (DCCA) and multifractal detrended cross-correlation analysis (MF-DCCA) are mainly applied to quantitatively study the dependency of the CSI 300 index futures market and spot market, which are more in line with the financial market. The results show that long-term memory and multifractal characteristics exist in the CSI 300 index futures and spot markets respectively. Meanwhile, there are obvious cross-correlation characteristics between futures and spot markets, and the cross-correlation is multifractal. The results can provide a better reference for the nonlinear dependency between the markets and the complex mechanisms.
    References | Related Articles | Metrics