Archive

15 August 2020, Volume 41 Issue 8 Previous Issue    Next Issue
---
Information & Control
Mechanical Engineering
Materials & Metallurgy
Resources & Civil Engineering


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Information & Control

Select

A View Reconstruction Method Based on Deep Network ZHANG Zhi-min， QIAO Jian-zhong， LIN Shu-kuan， WANG Pin-he 2020, 41 (8):  1065-1069.  DOI: 10.12068/j.issn.1005-3026.2020.08.001 Abstract ( 615 )   HTML   PDF (868KB) ( 721 )   To deal with stereo matching in the environment of only a single view， a full convolution reconstruction model with weighted local contrast normalization constraint is proposed on the basis of the existing view reconstruction network model Deep3D. This model adopts the improved full convolutional neural network architecture as the feature extraction module of the model to reduce the training parameters and training time， and to increase the nonlinearity of the model. In order to further improve the accuracy of reconstruction， a new constraint condition based on weighted local comparison normalization is designed， and a loss optimization function combining structural similarity (SSIM) cost and L1 cost is used to optimize the model. Experiments were carried out on the KITTI 2015 dataset， and compared with the Deep3D model and subsequent improvements. The experimental results show that the generated right view has a great improvement in SSIM and peak signal to noise ratio when only the left view is used as the training data， which can meet the accuracy requirements of the right view in the stereo matching method. References | Related Articles | Metrics

Select

Verification of Distribution Network Connectivity Based on AP-LOF Outlier Group Detection SI Fang-yuan， HAN Ying-hua， ZHAO Qiang， WANG Jin-kuan 2020, 41 (8):  1070-1074.  DOI: 10.12068/j.issn.1005-3026.2020.08.002 Abstract ( 521 )   HTML   PDF (557KB) ( 652 )   In the existing methods for the verification of distribution network connectivity， the suspicious outliers are usually regarded as independent individuals with binary attributes， which is difficult to effectively identify and validate local outlier groups which are correlated with each other. Therefore， a verification method for distribution network connectivity is proposed based on AP-LOF outlier group detection. Users are clustered into multiple clusters by introducing affinity propagation (AP) clustering， and all of the cluster centers are then detected by the local outlier factor (LOF) algorithm. In this way， the outlier groups can be accurately identified. The actual user voltage data of a power company are used in the case study， and the results demonstrate the applicability and effectiveness of the AP-LOF algorithm in the verification of distribution network connectivity. References | Related Articles | Metrics

Select

Multi-characteristic Subnets Discovery and Analysis Based on Traceroute YAO Wei， ZHAO Hai， ZHU Jian， CHEN Xiang-yi 2020, 41 (8):  1075-1082.  DOI: 10.12068/j.issn.1005-3026.2020.08.003 Abstract ( 653 )   HTML   PDF (738KB) ( 678 )   The studies on internet measurement have facilitated the development of router-level topology discovery， while subnets in the network layer provide a more detailed intermediate complementary view. In order to deal with the low accuracy caused by insufficient subnet boundary conditions and completeness， a multi-characteristic subnet discovery algorithm was proposed. The characteristics of the traceroute path of IP in the same subnet were studied， and were then combined to generate more precise subnet boundary determination conditions. By filtering the completeness of a subnet， the search space of the candidate subnet was narrowed， and the problem of subnet discovery was solved iteratively. The experimental results show that the proposed algorithm can discover subnets more accurately than other existing algorithms， reduce false positive rate， and improve efficiency. Finally， subnets were inferred on six geographically disperse ISPs， and the common subnet characteristics appearing in these ISPs are analyzed. References | Related Articles | Metrics

Select

RoI Extraction for Vehicular Thermal Infrared Pedestrian Detection LIU Qiong， LUO Qing， PENG Shao-wu 2020, 41 (8):  1083-1090.  DOI: 10.12068/j.issn.1005-3026.2020.08.004 Abstract ( 608 )   HTML   PDF (847KB) ( 662 )   Thermal infrared images are suitable for pedestrian detection in low illumination such as at night. The grayscale distribution of background in an infrared image vehicle-mounted varies obviously and pedestrian is easily confused with background interference and it is difficult to catch a pedestrian in the distance. The system recall rate and false alarm rate requirements can’t be achieved through extracting RoI with double threshold segmentation method. We construct a new RoI extraction method consisting of image preprocessing， RoI generation and RoI post processing etc. An expanding maximum filter is designed to enhance image contrast. Adaptive double threshold segmentation is improved by Haar-like feature. Computing efficiency is raised by designing incremental model. Besides， filters considering gray-scale temporal feature and spatial symmetry feature of a pedestrian are presented to remove false RoI. Comparing with the benchmark method， our method improves recall rate by 49% when the number of false RoIs is less than 40 per frame. And RoI extraction speed isn’t lower than 18 frames per second. References | Related Articles | Metrics

Select

A Web Spam Link Detection Method Based on Web Page Structure and Text Features YANG Wang， JIANG Yong-han， ZHANG San-feng 2020, 41 (8):  1091-1096.  DOI: 10.12068/j.issn.1005-3026.2020.08.005 Abstract ( 553 )   HTML   PDF (534KB) ( 644 )   The existing spam website detection methods are mainly aimed at self-built spam websites， and not suitable for injected spam websites because of the low efficiency of link detection. This paper proposes a new detection method， in which a detection framework is based on multi-dimensional features of webpage structure and text. The framework divides the webpage into blocks. Then content features are extracted by calculating odd ratio and structural features based on tags， attribute keys and attribute values are extracted by using the one-hot rate. The detection model is generated by proper machine learning and used to detect spam links. The detection accuracy of this framework is increased by up to 13%， compared with the algorithms based on content detection and on blacklist matching. References | Related Articles | Metrics

Mechanical Engineering

Select

Optimization Design and Dynamics Analysis of Vehicle Suspension System LI Xiao-peng ， LI Fan-jie， YANG Ling-xue， LIU Xiao-long 2020, 41 (8):  1097-1102.  DOI: 10.12068/j.issn.1005-3026.2020.08.006 Abstract ( 914 )   HTML   PDF (533KB) ( 1268 )   To improve the comprehensive damping performance of vehicle suspension system with inerter， the system with inerter， spring and damper was modeled. Genetic algorithm was used to optimize the suspension parameters， and the theory of vibration power flow was used to optimize the selection of the damping element bushing. Based on the numerical solution of the model， we discussed the dynamic response of the system before and after the parameter optimization and the influence of the bushing parameters on the power transmission. The research results show that， the parameters obtained by the optimization algorithm can effectively improve the comprehensive damping performance of the system， as compared with the design parameters. The theoretical calculation and simulation data mutually verify the correctness of the model. The optimized selection of the bushing is helpful to further improve the damping performance of the vehicle suspension system. References | Related Articles | Metrics

Select

Application of Non-smooth NES in Vibration Suppression of Rotor-Blade Systems CAO Yan-bo， LI Zhi-ao， HAN Jin-chao， YAO Hong-liang 2020, 41 (8):  1103-1110.  DOI: 10.12068/j.issn.1005-3026.2020.08.007 Abstract ( 663 )   HTML   PDF (985KB) ( 777 )   The vibration of the rotor-blade system is suppressed by a non-smooth nonlinear energy sink (NSNES) with piecewise linear stiffness beams. Firstly， the structure and working principle of the NSNES are introduced， and then the dynamic model of rotor-blade-NSNES system is established by using the Lagrange equation. Finally， the numerical method is used to analyze the NSNES ability to suppress the vibration of rotor and blade when the coupled system is in steady state resonance. Under the given parameters， the inhibition rate of the NSNES attached to the tip of the blade on rotor vibration can reach 68%， and the inhibition rate on blade vibration can reach 62%. The NSNES vibration suppression capability is compared with the vibration damping capability of a linear dynamic vibration absorber with the same mass as the NSNES. References | Related Articles | Metrics

Select

Experimental Research on Micro-milling of Micro-textured Spiral Micro-milling Cutter Fabricated on Low-Speed WEDM GONG Ya-dong， JIN Li-ya， SUN Yao， SU Zhi-peng 2020, 41 (8):  1111-1115.  DOI: 10.12068/j.issn.1005-3026.2020.08.008 Abstract ( 534 )   HTML   PDF (839KB) ( 662 )   A spiral micro-milling cutter with micro-texture on the flank is fabricated on a five-axis low-speed wire-cut electrical discharge machining (WEDM) with a rotary mechanism. A theoretical model for cutting force of micro-edge unit of spiral micro-milling cutter with micro-texture was established， and a comparative experiment of micro-textured micro-milling cutter and conventional micro-milling cutter was carried out. The results show that the cutting force of the micro-textured spiral micro-milling cutter is reduced by 30%-40% compared with that of the conventional tool. Under the same processing conditions， the surface roughness of the micro-textured spiral micro-milling cutter is reduced to 0.745μm， while the surface roughness processed by the conventional micro-milling cutter is 1.130μm. References | Related Articles | Metrics

Select

Intelligent STEP-NC-Compliant Micro-process Planning Based on Rules and Hybrid Algorithm ZHANG Yu， WANG Zhi-wei， LI Dong-sheng， GONG Ya-dong 2020, 41 (8):  1116-1122.  DOI: 10.12068/j.issn.1005-3026.2020.08.009 Abstract ( 597 )   HTML   PDF (875KB) ( 648 )   Aimed at the poor intelligence and low efficiency of STEP-NC-compliant micro-process planning， an intelligent STEP-NC-compliant micro-process planning method based on rules and hybrid algorithm was proposed. In this method， a rule-based algorithm for matching manufacturing resources is proposed to choose the corresponding machine tools and cutting tools for each workingstep. Then， taking the shortest tool exchanging time as the optimization target， the hybrid algorithm which combines chaos algorithm with the genetic algorithm is used to optimize the STEP-NC-compliant workingstep sequences. Finally， taking the shortest machining time and the lowest machining cost as optimization objectives， the hybrid algorithm is used to optimize the STEP-NC-compliant machining parameters， which results in obtaining the optimal STEP-NC-compliant micro-process planning. The effectiveness and feasibility of this method was verified by using cases. References | Related Articles | Metrics

Select

Powder Mixing Mechanism of Laser Cladding Forming for Adaptive FGM XIN Bo， CHENG Guang， YAO Jun， GONG Ya-dong 2020, 41 (8):  1123-1128.  DOI: 10.12068/j.issn.1005-3026.2020.08.010 Abstract ( 533 )   HTML   PDF (3366KB) ( 798 )   Fast and accurate mixing of multiphase powder is the foundation of forming parts from adaptive functional graded materials(A-FGM). In order to improve the powder mixing homogeneity driven by gas， a numerical analysis model of gas-solid two-phase flow was established. The Reynolds time average method was used for numerical simulation. A kind of powder mixing equipment driven by carrier gas was designed. A finite element method based on ANSYS-FLUENT was used to analyze the effect of mixing parameters and configurations on the flow field in the powder mixer. The experiment for testing mixing homogeneity based on elemental analysis and image processing was designed. The results show that the gas-dynamic mixing mechanism of the alloy powders is mainly in convective mix. As the average velocity and displacement of the powders increase， the powder flowability can be improved to increase the mixing homogeneity. References | Related Articles | Metrics

Select

Multi-objective Optimization of Tool Geometry Parameters in Turning Zirconia Ceramics MA Lian-jie， ZUO Yu-chen， ZHOU Yun-guang， FU Hai-ling 2020, 41 (8):  1129-1134.  DOI: 10.12068/j.issn.1005-3026.2020.08.011 Abstract ( 653 )   HTML   PDF (1682KB) ( 1042 )   The cutting force and tool wear were measured through the zirconia turning experiment， and the ratio of workpiece material removal to tool wear was as a quantitative index of tool utilization. The single-factor experimental values were trained and predicted by BP neural network that was improved by particle swarm optimization (PSO).The one-dimensional models describing the relationship of tool utilization/cutting force and the geometric parameters of each tool were established by least-squares fitting， and the reliability of the models was tested by the correlation coefficient. The multivariate models based on the one-dimensional models are proposed too. The multivariate models were solved by PSO combined with orthogonal experimental values， and was proved to be more accurate through experiments. Taking the multivariate models as the objective function and the maximum tool utilization/minimum cutting force as the optimization goals， the tool geometry parameters were optimized by PSO， and the experiments show that the optimized tool geometry parameters are reasonable. References | Related Articles | Metrics

Select

Study on Buffer Protection for Penetrator with Aluminum Foam-Filled Thin-Wall Structure LUO Hai-tao， MENG Xiang-zhi， LI Yu-xin， LIU Guang-ming 2020, 41 (8):  1135-1139.  DOI: 10.12068/j.issn.1005-3026.2020.08.012 Abstract ( 478 )   HTML   PDF (1254KB) ( 618 )   When a high-speed penetrator carrying detection equipment penetrates planetary bodies at high speed， the scientific instruments in it are impacted by high g value and easily damaged. The buffer protection structure for scientific instrumentation is essential for improving the survival rate. This work suggested a penetrator with a multi-layered energy absorbing structure where the foam-filled thin-wall structure (abbreviated as FTS) is applied to the penetrating vibration-damping structure to improve the survival rate of the penetrator. The penetrating process of the penetrator into the planetary medium is simulated in LS-DYNA. Then， the reliability of the penetrator’s finite element model was verified by the impulse response test and simulation. The results suggest that FTS has a beneficial effect on isolation impact and energy absorption and provides an important solution for the research and development of penetrator engineering prototype. References | Related Articles | Metrics

Select

Influence of the Throttling Plate Hole Diameter and Flow Rate on the Flow-Induced Noise for Nuclear Level Pipeline XIE Yi， Xi Dong， LIU Jian， LIU Shuai 2020, 41 (8):  1140-1147.  DOI: 10.12068/j.issn.1005-3026.2020.08.013 Abstract ( 542 )   HTML   PDF (1977KB) ( 782 )   The simulation model of flow-vibration-radiation noise was established for the throttling pipe used in the nuclear reactor. The mechanism of generating radiation noise and the influence of throttling hole diameter and flow rate on the vibration and noise were studied by the experiment and simulation. The radiation noise generates because of the wake vortices in the flow field of throttling pipe. When the frequency of the periodically exciting force generated on the pipe wall by the fluid in the pipe approaches that of the corresponding pipe modal， the vibration is enhanced， resulting in the radiation noise. Moreover， the vibration and radiation noise reduce with the increase of the throttling hole diameter， and enhance with the increase of the inlet flow rate. References | Related Articles | Metrics

Materials & Metallurgy

Select

Fatigue Property of Spoke Steel S500LF GAO Cai-ru， ZHU Chang-you， ZHANG Da-wei， DU Lin-xiu 2020, 41 (8):  1148-1152.  DOI: 10.12068/j.issn.1005-3026.2020.08.014 Abstract ( 473 )   HTML   PDF (1240KB) ( 679 )   An experiment was carried out on the high frequency fatigue testing machine PX-100 and with the method of progressively increasing/decreasing stress to determine the fatigue limit of wheel spoke steel S500LF on the condition that the vibration frequency was 100~120Hz and the tensile-compressive stress was symmetrical. The fatigue limit was 291MPa by the mathematical statistical analysis. When this value was used as an estimator of the maternal 50% survival rate， the relative error was no more than ±5% with a confidence level of 95%. The fatigue life at different stress levels was measured by the multi-sample method according to the measured fatigue limit. Based on this， the S-N relation curve was drawn and the S-N curve equation was regressed. Besides， the fracture of the samples was analyzed theoretically， and the result shows the good toughness of the test steel. References | Related Articles | Metrics

Select

Operation Parameters Optimization of Blast Furnaces Based on Data Mining and Cleaning LIU Xin， ZHANG Wei-jun， SHI Quan， ZHOU Le 2020, 41 (8):  1153-1160.  DOI: 10.12068/j.issn.1005-3026.2020.08.015 Abstract ( 648 )   HTML   PDF (1952KB) ( 1050 )   Effective mining of mass production data helps to improve the productivity and the level of management to realize “smart steel works”. The production data for the last 4 years of one steel works were collected， and the box plot was used to clean the data to improve their quality. Twenty-three characteristic parameters affecting hot metal quality and yield were selected by technological theory and expertise combined with the random forest algorithm. Hot metal yield and Si+Ti content were taken as the objective parameters， which could be divided into three categories by k-means cluster analysis. Thirteen parameters contributing to the wide range fluctuation of hot metal yield and quality were obtained after the comprehensive analysis of classification results and characteristic parameters， and the reasonable variable ranges of corresponding parameters were provided. The research can guide the stable operation of blast furnaces and the application of data mining in the iron and steel industry. References | Related Articles | Metrics

Resources & Civil Engineering

Select

Automatic Discontinuity Classification and Parameter Calculation from Rock Mass 3D Point Cloud GUO Jia-teng， ZHANG Zi-rui， MAO Ya-chun， LIU Shan-jun 2020, 41 (8):  1161-1166.  DOI: 10.12068/j.issn.1005-3026.2020.08.016 Abstract ( 614 )   HTML   PDF (2356KB) ( 964 )   The structural plane spacing is an important parameter in rock mass stability and mechanical properties analysis. It is widely used in the numerical computation of rock mechanics， mining engineering， slope monitoring and other fields. Based on the three-dimensional rock mass slope point cloud data acquired by non-contacting surveying method， this paper proposes a structural surface refinement classification method using density clustering. Projection transformation and scattered point fitting are used after a previous step of general discontinuity classification. The refinement classification is used to compute the structural plane spacing and the rock mass joint number. A prototype system for parameter calculation and analysis of structural surface refinement classification and spacing was designed and developed. The real case experiment and analysis show that the proposed method performs effectively in realizing the automatic refinement classification of structural planes， and in calculating the related parameters such as structural surface spacing， which may provide further support for rock mass quality classification and rock mass stability analysis. References | Related Articles | Metrics

Select

Method for Determining the Lower Limit of Statistical Joints Trace Length in Underground Engineering Rock Mass WU Chao， LI Yuan-hui， XU Shuai， DAI Xing-hang 2020, 41 (8):  1167-1173.  DOI: 10.12068/j.issn.1005-3026.2020.08.017 Abstract ( 590 )   HTML   PDF (1101KB) ( 716 )   Taking the actual rock mass joint information from a gold mine in Shandong Province as samples， a method is studied to determine the lower limit of the statistical joints trace length in underground engineering rock mass by cluster analysis and its evaluating indicators with the full-scale test. Starting from the definition and characteristics of the lower limit， the DBI (Davies-Bould in index) is used to divide dominant joint sets and determine the best setting scheme of dominant joints. The joint set can become the dominant one if the discrete coefficient k is greater than 20， and the discrete coefficient k with its probability distribution index n together is used to analyze and determine the lower limit value. Furthermore， the method of determining the lower limit value of the statistical joints trace length under different rock mass conditions is developed in order to eliminate random joints and optimize the sample data of rock mass joints， thus getting spatial distribution characteristics of rock mass joints. References | Related Articles | Metrics

Select

Characteristics of Water-Rock Reaction and Effect of Reynolds Number on Dissolution Rate for Fractures WANG Zhe-chao， WEI Ru-lei， BI Jing-chao， WU Zhen-hua 2020, 41 (8):  1174-1179.  DOI: 10.12068/j.issn.1005-3026.2020.08.018 Abstract ( 616 )   HTML   PDF (732KB) ( 619 )   Based on the first large-scale underground water-sealed oil storage facility in China， viz Huangdao underground oil storage facility， the experiments of water-rock interaction in single fractures of granite at different flow rates were performed. The characteristics of water-rock reaction were observed and the effects of Reynolds number on the dissolution rate of soluble minerals on the surface of granite were analyzed. The results show that the main mineral of the chemical reactions of granite in acidic conditions is sphene. The dominant chemical reaction between water and rock are CaTiSiO5+4H+→TiO2++H4SiO4+Ca2+， H2O+CO2HCO-3+H+ and TiO+2+2H2O→H2TiO3↓+2H+. The chemical reaction rate is the highest in the first 10 days， then gradually decreases until equilibrium states are reached. Fluid flow can significantly increase the dissolution rate of sphene， however， the reaction rate in the experiment with Reynolds number of 500 is higher than that with Reynolds number of 2500， due to higher flow rate reducing the transport rate of solute， making the macro chemical reaction rate lower. References | Related Articles | Metrics

Select

Experimental Study on the Microwave Radiation of Stressed Rock Under Cold Sky Background XU Zhong-yin， LIU Shan-jun， WU Li-xin， CHE De-fu 2020, 41 (8):  1180-1187.  DOI: 10.12068/j.issn.1005-3026.2020.08.019 Abstract ( 521 )   HTML   PDF (1049KB) ( 632 )   How environmental factors affect microwave radiation observation was analyzed. Based on the analysis， outdoor experiments were carried out with rock test machine， microwave radiometer， acoustic emission instrument， temperature tester and other equipment to observe microwave radiation characteristics of elastically deformed rock with cyclic loading under cold sky background. Results indicate that the microwave radiation energy changes generated from deformed rock can be detected reliably under cold sky background. In the elastically deformed granite， the microwave radiation energy changes and stress present the positive correlation， with the correlation coefficient of 0.94. The temperature change of the rock surface is positively correlated with the stress too， but the temperature change lags behind the stress change， and the microwave brightness temperature increment is much larger than the surface temperature rise per unit stress. It is verified that the changes in the internal stress state of rock can be detected by microwave observation. References | Related Articles | Metrics

Select

Disintegration and Sedimentary Environment Analysis of the Originally-Define ‘Xingmincun Formation of Neoproterozoic Sinian System’ in South Liaoning CAO Yu-hao， TIAN De-xin， LU Chong-hai， SHAO Jiu-long 2020, 41 (8):  1188-1194.  DOI: 10.12068/j.issn.1005-3026.2020.08.020 Abstract ( 866 )   HTML   PDF (2175KB) ( 641 )   Based on the authors’ study on the original-define ‘Xingmincun Formation of Sinian System’， the characteristics of the glacial period environment were found in the fine grain quartz sandstone in the bottom of Zhoujiawaizi section of Xingmincun Formation， such as ice-rafting dropstone and fine laminary structure. In the bottom and upper part of Zhoujiawaizi section there are ice crystal impression and hailstone traces and other moraine traces. The Wangjiatanzi shale section of the original-define Xingmincun Formation belongs to the shallow sea facies open shelf subfacies sedimentary environment， producing different species of the medusa-like fossil which belong to the Sinian system. The structure of the medusa-like fossils produced in this layer is simple and small and the formation time should be earlier than that of Ediacaran. The Gandaozi limestone section of Xingmincun Formation belongs to the internal carbonate deposit. In view of the above research results， the authors consider that the sedimentary environment of the Zhoujiawzi sandstone， Wangjiatanzi shale and Gandaozi limestone of the original-define Xingmincun Formation is obviously different. It is necessary for original division of Xinmincun Formation to be disintegrated and divided into Zhoujiawaizi Formation， the Wangjiatanzi Formation and the Gandaozi Formation in the upper series of the Nanhua System. It is beneficial to the comparison and study of lithostratigraphy units in the late Neoproterozoic in China. References | Related Articles | Metrics

Select

Mechanism of Enhancing Separation Performance of Ilmenite by Magnetic Treatment of Sodium Oleate Solution YUAN Zhi-tao， XU Yuan-kai， MENG Qing-you， ZHAO Xuan 2020, 41 (8):  1195-1200.  DOI: 10.12068/j.issn.1005-3026.2020.08.021 Abstract ( 614 )   HTML   PDF (795KB) ( 592 )   The effect of magnetic treatment of sodium oleate solution on the flotation of ilmenite from titanaugite was studied. It is found that after magnetic treatment of sodium oleate， the recovery of titanaugite decreases from 75.0% to 60.6%， and the recovery of ilmenite decreases from 75.2% to 69.3%. The zeta potential of titanaugite shifts more positively than that of ilmenite. It is suggested that the selectivity of sodium oleate to ilmenite increases after magnetic treatment. The effects of magnetic treatment of sodium oleate on its electrical conductivity， surface tension and spectral properties are researched， and the mechanism of magnetic treatment is revealed. After magnetic treatment， the electrical conductivity and surface tension increase and the hydrogen bonds in the solution are weakened. Consequently， the oleate ions are released more， and increased and released oleate ions are selectively adsorbed on the surface of ilmenite. Hence， the floatability difference between ilmenite and titanaugite is enlarged. References | Related Articles | Metrics

Select

Infiltration Mechanism and Stability Analysis of Multilayer Soil Slope Under Rainfall Conditions SUN Zi-han， WANG Shu-hong， YANG Tian-jiao， LIU Huan 2020, 41 (8):  1201-1208.  DOI: 10.12068/j.issn.1005-3026.2020.08.022 Abstract ( 744 )   HTML   PDF (1096KB) ( 936 )   Based on the multilayer soil water content equation of VG (Van-Genuchten) model， the governing equation of water content and matrix suction is established， with the slope inclination angle taken into account， and the calculation method of infiltration depth of multilayer soil slope with different permeability coefficient ratios between layers is proposed. One-dimensional and two-dimensional models of multilayer soil are established by Seep/w plate in Geo-Studio software to analyze the formation of saturated stagnant water zone at soil interface during rainfall infiltration and the variation characteristics of multilayer soil slope stability under different rainfall conditions. The correctness of the calculation method is verified. The results show that the volume water content and pore water pressure at the interface of multilayer soil slope change greatly during rainfall. For multilayer soil slope with different permeability of each layer， the larger the ratio of permeability coefficients is， the more the rate of downward dissipation of stagnant water at the interface decreases， the larger the range of pore water pressure at the interface is. The pore water pressure increases sharply after the saturated stagnant water area forms， which leads to the sudden decrease of shear strength of soil and the large-scale reduction of stability coefficient of soil slope. The conclusions provide a reference for the early warning of soil slope under rainfall conditions. References | Related Articles | Metrics

Select

Research on Suitability of Creative Industry Distribution Based on MaxEnt ZHAO Qi， LIU Fu-ying 2020, 41 (8):  1209-1216.  DOI: 10.12068/j.issn.1005-3026.2020.08.023 Abstract ( 467 )   HTML   PDF (1908KB) ( 544 )   An ecological niche model of creative industry was developed on the basis of the geographic characteristics of creative industry parks and 23 factors associated with the environment of cities were selected. The maximum entropy model (MaxEnt) was applied to determine the contribution of each factor and identify 8 major contributing factors. The fuzzy membership was applied to study the effect of environmental factors on the creative industry. The model results were integrated with the weight of environmental factors to get the suitability of creative industry and to produce predictive maps of site suitability. Then， based on the GIS spatial analysis， the cities were categorized into four zones， including unsuitable， low-suitable， moderatly-suitable， and highly-suitable regions， whose suitability ranges from low to high. The results showed that highly-suitable regions are mostly located in the eastern coastal provinces and provincial cities in China and that the predicted results are similar to the actual ones， which confirms the high reliability of the model. References | Related Articles | Metrics