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    AI Robotics Column
    An Algorithm for Image Denoising and Enhancement of Surface Defects of Electronic Commutator
    PENG Ning, WU Hao, QI Zi-yuan, LIU Yan-xi, SONG Hong
    2023, 33(3): 1-8.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.001
    Abstract ( )   PDF (629KB) ( )  
    Aiming at the problems of low contrast, obscure details and excessive noise of the surface defect image of electronic commutator in industry, a new image enhancement method for the surface defect image of electronic commutator is proposed in this paper. Firstly, aiming at the mixed noise problem on the surface of the electronic commutator, the median filter and wavelet threshold are combined to remove the noise. Then, the de-noised image is deblurred through DeBlurGAN V2 network. Finally, UACE, an adaptive contrast enhancement algorithm based on unsharp mask, is constructed with optimized USM and ACE to enhance the contrast of defects in the processed image. The experimental results show that the peak signal-to-noise ratio, contrast and information entropy of the image enhanced by the algorithm in this paper are improved, which proves that the algorithm in this paper can not only eliminate the noise in the image, but also effectively improve the contrast of the image.
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    Design of a Quadcopter Based on Ultrasonic Obstacle Avoidance
    SUN Xiao-hui, YANG Jin-guang
    2023, 33(3): 9-13.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.002
    Abstract ( )   PDF (401KB) ( )  
    This paper expounds the design of a quadcopter and proposes an overall solution that applies ultrasonic ranging technology to realize the automatic obstacle avoidance function of UAV. Firstly, algorithms such as Euler angle and extended Kalman filtering are applied to process the information collected by the MPU9250 sensor, calculate the position and attitude information, and adjust the PID parameters to realize the steady-state flight control of the quadrotor UAV. Secondly, the information collected by the SUI04 ultrasonic obstacle avoidance sensor is transmitted to the STM32H743 controller, and the corresponding instructions are output through algorithm processing to realize the obstacle avoidance function. Finally, after testing, in the outdoor low-speed flight state, the quadcopter UAV basically realizes the functions of fixed height flight and automatic obstacle avoidance. Therefore, it can be concluded that the automatic obstacle avoidance function of quadrotor UAV can be realized by ultrasonic ranging technology, and the obstacle avoidance effect is relatively stable and has certain practicality.
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    Ecological Hydrology and Water Resources Column
    Analysis on Typical Rainstorm Processes in Cangzhou Region on August 21st, 2022
    HA Jian-qiang, WANG He
    2023, 33(3): 14-19.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.003
    Abstract ( )   PDF (435KB) ( )  
    This paper studies the typical rainstorm in Cangzhou City, i.e. the “8·21” rainstorm in 2022, and describes in detail the time history distribution, spatial distribution, river flow, water storage in depressions, shallow groundwater, urban water accumulation, etc., and obtains the data results, which provide the basis for flood prevention and disaster reduction, and provide an illustrative basis for similar types of rainfall. At the same time, in order to make better use of rain and flood resources, countermeasures and suggestions are put forward.
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    Analysis and Research on Flood Disaster of Small Watershed in Middle Taihang Mountain
    DU Lan
    2023, 33(3): 20-25.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.004
    Abstract ( )   PDF (585KB) ( )  
    In October 2021, the central part of Taihang Mountain was hit by heavy rainfall for several consecutive days, and natural disasters such as floods and mudslides occurred in many places. This article evaluates the current flood control capacity of typical riverside villages in the mountain flood prevention and control area through on-site survey, based on the “Technical Requirements for Analysis and Evaluation of Mountain Flood Disasters” and the “Guidelines for Analysis and Evaluation of Mountain Flood Disasters”, combined with the hydrological analysis method of small watersheds in areas without data, and by analyzing and calculating the design flood of typical riverside villages in the mountain flood prevention and control area, the corresponding hazardous areas with different hazard levels are determined and risk maps are drawn. Based on the watershed model method, the regional rainfall warning indicators under different early rainfall conditions were comprehensively determined, providing certain technical support for the preparation of mountain flood disaster prevention plans and disaster prevention and control work in the region.
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    Water Balance Test and Analysis on an Electronic Technology Enterprise in Hebei Province
    NING Xi-jun, XIAN Xiao-dong, HOU Na-na, LUO Xiao, MA Kun-ru
    2023, 33(3): 26-32.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.005
    Abstract ( )   PDF (511KB) ( )  
    Hebei Province is short of water resources and freshwater resources, with per capita water consumption lower than internationally recognized levels. Industrial enterprises use a large and concentrated amount of water, and water-saving transformation can effectively save water resources. In order to improve the water use methods of enterprises, achieve scientific, reasonable, planned, and focused water use, improve water utilization efficiency, and avoid water resource waste, this article uses water balance testing to scientifically analyze the water use situation of an electronic technology enterprise in Hebei Province, comprehensively understand the pipeline network status of the enterprise, the current water use status of various parts(units), tap the potential of water use, propose reasonable suggestions, and improve the reuse rate of water use in the enterprise, to achieve the goal of strengthening water management, improving reasonable water use levels, saving the overall water resources of society, and providing a basis for relevant electronic technology enterprises to carry out water-saving transformation.
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    Remote Sensing and Ecological Environment Column
    Expansion and Quantitative Attribution of China’s Built-up Areas Based on Parameter Optimal Geodetector
    LIU Dan-dan, LI Yong-liang
    2023, 33(3): 33-39.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.006
    Abstract ( )   PDF (464KB) ( )  
    To study the spatiotemporal changes in urban built-up areas in China over the past 20 years from 2002 to 2021, promoting the urbanization process, and socially sustainable development in China, urban units in China were selected as the research objects. DMSP-OLOS data from 2002 and NPP-VIIRS night light data from 2021 were used, combined with indicators such as expansion speed, standard deviation ellipse, and spatial autocorrelation. Quantitative analysis of the spatial distribution characteristics in built-up areas is elaborated in two aspects: quantity structure and spatial distribution. Some factors are used as independent variables such as GDP difference, population difference, elevation, road network density, temperature difference, and rainfall difference. Expansion speed is used as the dependent variable. The driving force is quantitatively analyzed by parameter optimal geographic detector. 1) In the past 20 years, the expansion speed of urban built-up areas in our country has been mainly in medium and low speed, The annual expansion rate of the built-up areas in the eastern and northern coastal areas is higher than the national average. The middle reaches of the Yellow River and the southern coast are comparable to the national average, while the middle reaches of the Yangtze River, Southwest China, Northeast China and Northwest China are significantly lower than the national average. The eastern coastal areas have the fastest expansion speed and the smallest difference in urban development, while the center of gravity of China′s built-up areas moves 100.22 kilometers from the eastern coastal areas to the northwest. 2) The expansion speed of the built-up area has spatial heterogeneity, reflecting the accumulation of cold and hot spots. Cold spot areas are distributed in the northern and central regions of China and exhibit low-low clustering and high-low clustering, while hot spot areas are distributed in the southeastern coastal areas of China and exhibit high-high clustering and low-high clustering; 3) GDP,population are the main factors affecting the development of built-up areas, with the explanatory power of 0.6395, 0.4965, respectively. The interaction between various factors is either double factor enhancement or non-linear enhancement, with strong interaction between socioeconomic factors, and the strongest interaction between GDP and population factors. The explanatory power of 1.1361 shows a double-factor enhancement.
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    Effect of Bulking Sludge on MBR Membrane Fouling
    DAI Hong-Wei, WANG Ya-qin
    2023, 33(3): 40-44.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.007
    Abstract ( )   PDF (355KB) ( )  
    Membrane fouling limits the application of the MBR process. In order to better understand the process and mechanism of the impact of sludge bulking on the process of membrane fouling, an integrated MBR with bulking sludge was performed in the laboratory. By analyzing the extracellular polymeric substances (EPS), TMP (transmembrane pressure), and bulking-sludge-sedimentation, the results showed that the content of protein and polysaccharide content of bulking sludge was high; and it was difficult for bulking sludge to settle for its loose flocculent structure, which was easy to form a filter cake layer; Rc was the major factor leading to membrane fouling.
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    Experimental Study on Treatment of Micro-polluted River Water by Magnetic Coagulation Technology
    JING Chang-yong, LIANG Yun, JIN Ni-sha, DONG Bing
    2023, 33(3): 45-50.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.008
    Abstract ( )   PDF (524KB) ( )  
    In this paper, the micro-polluted river water is taken as the treatment object, and the removal effects of total phosphorus, turbidity, permanganate index, etc. of the river water before and after treatment are used as reference indicators. The influence factors such as precipitation time and dosing sequence were experimentally studied, and the optimal experimental conditions for the treatment of micro-polluted river water by magnetic coagulation technology were finally determined as follows: the optimal coagulant is ferric chloride, and the optimal dosing amount is 100 mg/L; the best dosage of magnetic powder is 200 mg/L; the best dosage of coagulation aid PAM is 1.00 mg/L) after 4 min, add PAM to stir quickly (250 r/min) for 1 min and finally stir slowly (80r/min) for 10 min; the optimum pH value is 6-8; the optimum precipitation time is 15 min.
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    Road and Bridge Engineering Column
    Type Selection and Key Technologies of Superstructure Construction of Bridge in Urban (Suburban) Railway
    LIANG Xian-wei, GUO Xiao-yu, LI Zi-lin, ZHANG Long-ming, ZHUANG Feng-ming
    2023, 33(3): 51-58.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.009
    Abstract ( )   PDF (689KB) ( )  
    Based on the analysis of the characteristics of urban (suburban) railways, bridge structural systems, girder types, and construction methods, the ideas and principles oftype selection for urban (suburban) railway bridges were proposed. And taking the first urban (suburban) railway project in Tianjin-the first sectionengineering of urban (suburban) railway project from downtown to Jinghai in Tianjin as an example, the key technologies of cantilever casting construction for the upper structure of large-span continuous girder bridge were summarized. In particular, the preloading method of construction bracket for 0# block, temporary consolidation measures between pier and girder, intelligentstretching technology of prestress, intelligent grouting process of prestressing duct and preloading method of construction hanging basket were explained in detail. This has an important reference significance for guiding the design and construction of large-span continuous box girder bridge in the urban (suburban) railways in China.
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    Pavement Performance Prediction Method Based on Equal-dimensional Grey Number Recursive Model Method
    HAN Jin-chuan, ZHUANG Feng-ming, WANG Lian-xiang, ZHANG Long-ming, GUO Xiao-yu
    2023, 33(3): 59-64.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.010
    Abstract ( )   PDF (357KB) ( )  
    Considering the shortcomings of strong subjectivity and poor comprehensiveness of the current domestic pavement performance prediction methods, this paper selects the pavement condition index(PCI)as the analysis index, and compares the prediction effects of three pavement performance prediction methods on the PCI index, namely, the PPI model of pavement performance degradation, the conventional GM(1,1)model and the equal-dimensional grey number progressive model. The results show that the prediction accuracy of the three models can meet the first-order accuracy. Among them, the posterior error ratio of the prediction results of the equal dimension grey number recursive model is the smallest, and the stability and accuracy of the prediction are the best, which is more suitable for the prediction of pavement performance.
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    Geotechnical Engineering Column
    Improvement on Pile-soil Stress Ratio of Pile-supported and Geosynthetics-reinforced Embankment Based on Hewlett Method
    ZHANG Yu-lin, JIANG Hai-jun, ZHANG Pei-Cheng, ZHOU Yi-tao, YAO Yuan-zhou
    2023, 33(3): 65-72.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.011
    Abstract ( )   PDF (606KB) ( )  
    The influence of tensioned membrane effect on the calculation of pile-soil stress ratio of pile-supported and geosynthetics-reinforced embankment is improved, and a new calculation method is proposed. Primarily via static equilibrium equations of infinitesimal section of geogrid between the piles, according to the assumption that the reaction on foundation below the geogrid fit Winkler foundation model, and coupling membrane effect and soil arching effect of fill above the geogrid, the pile-soil stress ratios below the reinforcement net and differential settlement between piles and soil in the pile-supported reinforced embankment are obtained. In addition, this paper also analyzes the influence on the pile-soil stress ratio of various related factors, and proves the feasibility of this method through practical projects. The results show that the pile-soil stress ratios below the reinforcement net will increase with the increase of the tensile strength of geo-grids and the height of fill, and decrease with the increase of pile spacing, while the pile-soil stress ratios above the reinforcement net are the complete opposite of the former. The pile-soil stress ratio will change with different forms of placing pile, and the maximum stress ratio is obtained when arrange piles in the quincunxes. The calculated values of the pile-soil stress ratios is much closer to the measured ones.
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    Effect of Freeze-thaw and Suction on Permeability of Unsaturated Soil
    LI Xia
    2023, 33(3): 73-78.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.012
    Abstract ( )   PDF (587KB) ( )  
    The change of unsaturated soil permeability under freeze-thaw action is not only affected by freezing negative temperature, freeze-thaw times and other factors, but also affected by suction of samples. To study the evolution law of soil permeability coefficient under freeze-thaw cycles and suction, the test piece will experience different times of freezing and thaw cycle to control suction in two ways to establish full suction soil-water characteristic curve for VG model fitting and calculate the permeability coefficient of different freeze and melting cycles within the range of full absorption. The results show that the full suction soil-water characteristic curve gradually decreases with the increase of the permeability in the low suction phase; the permeability coefficient and the permeability after three times and the permeability coefficient gradually decreases with the absorption.
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    Optimization of Soil Particle Dispersion Method in Grain Distribution Analysis Densimeter Test
    XIE Fang-yuan
    2023, 33(3): 79-84.  DOI: 10.16046/j.cnki.issn2096-5680.2023.03.013
    Abstract ( )   PDF (302KB) ( )  
    Aiming at the problem of soil particle dispersion in grain distribution analysis densimeter test, the orthogonal test design method was used to analyze the influence of soaking, boiling and dispersant on soil particle dispersion, and the optimal scheme was determined. According to the analysis results and the actual project, the feasibility of the scheme is verified by comparison, and the efficiency of grain distribution analysis densimeter test is improved, time cost is saved.
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