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Resilience patterns of human mobility in response to extreme urban floods

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National Science Review 2023年第8期10卷 121-133页

作者： Junqing Tang Pengjun Zhao Zhaoya Gong Hongbo Zhao Fengjue Huang Jiaying Li Zhihe Chen Ling Yu Jun Chen School of Urban Planning and design Shenzhen Graduate School Peking University 2. Key Laboratory of Earth Surface System and Human-Earth Relations of Ministry of Natural Resources of China Shenzhen Graduate SchoolPeking University School of Urban and Environmental Sciences Peking University Key research institute of yellow river Civilization and Sustainable Development&Collaborative Innovation Center on yellow river Civilization Henan Province and Ministry of Education Henan University 5. Key National Geomatics Center of China

Large-scale disasters can disproportionately impact different population groups, causing prominent disparity and inequality, especially for the vulnerable and marginalized. Here, we investigate the resilience of human mobility under the disturbance of the unprecedented ‘720’ Zhengzhou flood in China in 2021 using records of 1.32 billion mobile phone signaling generated by 4.35 million people. We find that although pluvial floods can trigger mobility reductions, the overall structural dynamics of mobility networks remain relatively stable. We also find that the low levels of mobility resilience in female, adolescent and older adult groups are mainly due to their insufficient capabilities to maintain business-as-usual travel frequency during the flood. Most importantly, we reveal three types of counter-intuitive, yet widely existing,resilience patterns of human mobility(namely, ‘reverse bathtub’, ‘ever-increasing’ and ‘ever-decreasing’ patterns), and demonstrate a universal mechanism of disaster-avoidance response by further corroborating that those abnormal resilience patterns are not associated with people’s gender or age. In view of the common association between travel behaviors and travelers’ socio-demographic characteristics, our findings provide a caveat for scholars when disclosing disparities in human travel behaviors during flood-induced emergencies.

关键词： disaster resilience urban flood human mobility Zhengzhou flood mobile phone data

Regularity of sediment transport and sedimentation during floods in the lower yellow river,China

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International Journal of Sediment research 2020年第1期35卷 97-104页

作者： Qingchao Guo Zhao Zheng Liemin Huang Anjun Deng State Key Laboratory of Simulation and Regulation of Water Cycle in river Basin(SKL-WAC) China institute of Water Resources and Hydropower research(IWHR) surveying design and research institute of yellow river henan province

The flood season is the main period of flow,sediment transport,and sedimentation in the lower yellow river(LYR).Within the flood season,most of the flow,sediment transport,and sedimentation occurs during flood *** of the importance of floods in forming riverbeds in the LYR,the regularity of sediment transport and sedimentation during floods in the LYR was *** daily discharge and sediment transport rate data for the LYR from 1960 to 2006 were used.A total of 299 floods were selected;these floods had a complete evolution of the flood process from the Xiaolangdi to the Lijin hydrological *** five hydrological stations(Xiaolangdi,Huayuankou,Gaocun,Aishan,and Lijin),a correlation was first established for floods of different magnitudes between the average sediment transport rate at a given station and the average sediment concentration at the closest upstream *** results showed that the sediment transport rate at the downstream station was strongly correlated with the inflow(upstream station) sediment concentration during a flood event.A relation then was established between sedimentation in the LYR and the average sediment concentration at the Xiaolangdi station during a flood *** this relation,the critical sediment concentrations were obtained for absolute erosion,sedimentation equilibrium,and absolute deposition during floods of different magnitudes in the *** results of the current study contri b ute to a better understanding of the mechanisms of sediment transport and the regularity of sedimentation in the LYR during floods,and provide technical support to guide the joint operation of reservoirs and the regulation of the LYR.

关键词： Sediment transport Floods Sedimentation Lower yellow river

Non-precious metal electrocatalysts for two-electron oxygen electrochemistry: Mechanisms, progress, and outlooks

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Journal of Energy Chemistry 2022年第6期31卷 54-69,I0003页

作者： Yuhan Wu Jianhui Sun Shixue Dou Jingyu Sun School of Environment Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control-Ministry of EducationHenan Normal UniversityXinxiang 453007HenanChina College of Energy Soochow Institute for Energy and Materials InnovationsKey Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006JiangsuChina institute for Superconducting and Electronic Materials University of WollongongWollongongNSW 2522Australia

Hydrogen peroxide (H_(2)O_(2)) is a valuable chemical for a wide variety of applications. The environmentally friendly production route of the electrochemical reduction of O_(2)to H_(2)O_(2) has become an attractive alternative to the traditional anthraquinone process. The efficiency of electrosynthesis process depends considerably on the availability of cost-effective catalysts with high selectivity, activity, and ***, there are many outstanding issues in the preparation of highly selective catalysts, the exploration of the interface electrolysis environment, and the construction of electrolysis devices, which have led to extensive research efforts. Distinct from the existing few comprehensive review articles on H_(2)O_(2) production by two-electron oxygen reduction, the present review first explains the principle of the oxygen reduction reaction and then highlights recent advances in the regulation and control strategies of different types of catalysts. Key factors of electrode structure and device design are discussed. In addition,we highlight the promising co-production combination of this system with renewable energy or energy storage systems. This review can help introduce the potential of oxygen reduction electrochemical production of high-flux H_(2)O_(2) to the commercial market.

关键词： 2e-ORR(oxygen reduction reaction) H_(2)O_(2) Heteroatom doping Single atom Carbon-based catalyst

Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

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Journal of Advanced Ceramics 2024年第2期13卷 189-197页

作者： Pengfei Sang Le Zhang Jian Kang Mingzhou Li Shiwei Chen Peng Yang Bingheng Sun Yang Li Wieslaw Strek Hao Chen Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronics EngineeringJiangsu Normal UniversityXuzhou 221116China Jiangsu Xiyi Advanced Materials research institute of Industrial Technology Xuzhou 221400China Xuzhou EAGLED Technology Co. Ltd.Xuzhou 221116China Xuzhou Kangna Advanced Materials Technology Co. Ltd.Xuzhou 221116China Xuzhou Fuchang Electronic Technology Co. Ltd.Xuzhou 221116China Shanghai institute of Optics Fine Mechanics Chinese Academy of SciencesShanghai 201800China School of Material Science and Engineering Shanghai Institute of TechnologyShanghai 201418China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China institute of Low Temperature and Structure research Polish Academy of SciencesWroclaw 50-422Poland

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting *** based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal *** this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal *** prepared ceramics exhibited excellent thermal performance and no yellow ring *** this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive *** particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

关键词： Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG angular color uniformity high thermal stability high-power laser lighting

Amplification of Flood Risks by the Compound Effects of Precipitation and Storm Tides Under the Nonstationary Scenario in the Coastal City of Haikou,China

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International Journal of Disaster Risk Science 2022年第4期13卷 602-620页

作者： Hongshi Xu Xi Zhang Xinjian Guan Tianye Wang Chao Ma Denghua Yan yellow river Laboratory Zhengzhou UniversityZhengzhou 450001China institute of Hydropower and Hydroinformatics Dalian University of TechnologyDalian 116024China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China China institute of Water Resources and Hydropower research Beijing 100038China

In the context of climate change,coastal cities are at increased risk of extreme precipitation and sea level rise,and their interaction will aggravate coastal *** the potential change of compound floods is valuable for flood risk *** this study,an integrated approach coupling the hydrological model and copulabased design of precipitation and storm tides was proposed to assess the compound flood risk in a coastal city—Haikou,*** copula model,most-likely weight function,and varying parameter distribution were used to obtain the combined design values of precipitation and storm tides under the nonstationary scenario,which were applied to the boundary conditions of the 1D-2D hydrological ***,the change of the bivariate return periods,design values,and compound flood risks of precipitation and storm tides were *** results show that the bivariate return period of precipitation and storm tides was reduced by an average of 34%under the nonstationary *** maximum inundation areas and volumes were increased by an average of 31.1%and 45.9%respectively in comparison with the stationary ***,we identified that the compound effects of precipitation and storm tides would have a greater influence on the flood risk when the bivariate return period is more than 50 years,and the peak time lag had a significant influence on the compound flood *** proposed framework is effective in the evaluation and prediction of flood risk in coastal cities,and the results provide some guidance for urban disaster prevention and mitigation.

关键词： Copula function Flood risk Haikou City Nonstationary scenario Urban hydrological model

Ecosystem service values of gardens in the yellow river Basin,China

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Journal of Arid Land 2022年第3期14卷 284-296页

作者： GE Qianqian XU Wenjie FU Meichen HAN Yingxin AN Guoqiang XU Yuetong School of Land Science and Technology China University of Geosciences(Beijing)Beijing 100083China China Land surveying and Planning institute Beijing 100035China Shandong Urban and Rural Planning design institute Jinan 250013China Territorial Spatial Planning institute of Shandong province Jinan 250014China College of Geography and Environment Shandong Normal UniversityJinan 250358China Key Laboratory of Land Use Ministry of Natural ResourcesShandong BasisJinan 250014China

Studies on the ecosystem service value(ESV)of gardens are critical for informing evidence-based land management practices based on an understanding of the local *** analyzing equivalent value factors(EVFs),this paper evaluated the values of 11 ecosystem services of gardens in the yellow river Basin of China in ***-precision land use survey data were used to improve the accuracy of the land use classification,garden areas,and spatial distribution of the ESVs of *** results showed that garden ecosystem generally had high ESVs,especially in terms of the ESV of food production,which is worthy of further research and application to the practice of land use planning and ***,the value of one standard EVF of ecosystem services in 2019 was 3587.04 CNY/(hm^(2)·a),and the ESV of food production of gardens was much higher than that of *** ecosystem provided an ESV of 1348.66×10^(8)CNY/a in the yellow river *** areas with the most concentrated ESVs of gardens were located in four regions:downstream in the Shandong-henan zone along the yellow river,mid-stream in the Shanxi-Shaanxi zone along the yellow river,the Weihe river Basin,and upstream in the Qinghai-Gansu-Ningxia-Inner Mongolia zone along the yellow *** spatial correlation of the ESVs in the basin was significant(global spatial autocorrelation index Moran's I=0.464),which implied that the characteristics of high ESVs adjacent to high ESVs and low ESVs adjacent to low ESVs are *** the yellow river Basin,the contribution of the ESVs of gardens to the local environment and economy varied across *** also put forward some suggestions for promoting the construction of ecological civilization in the yellow river *** findings of this study provide important contributions to the research of ecosystem service evaluation in the yellow river Basin.

关键词： ecosystem service evaluation garden ecosystem equivalent value factors spatial autocorrelation analysis yellow river Basin

Individual and combined influences of main loading parameters on granite damage development under ultrasonic vibration

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Journal of Mountain Science 2021年第12期18卷 3366-3379页

作者： ZHANG Cheng ZHAO Da-jun ZHANG Shu-lei ZHOU Yu College of Construction Engineering Jilin UniversityChangchun 130026China Key Laboratory of Rock Mechanics and Geohazards of Zhejiang province Shaoxing UniversityShaoxing 312000China yellow river Survey Planning and Design Institute Co.Ltd.Zhengzhou 450003China

Ultrasonic vibration technology has great potential to weaken hard *** the effect of ultrasonic vibration loading parameters is essential to accelerate the application of this technology in practical rock *** the present work,three-factor mixed-level orthogonal ultrasonic vibration rock breaking tests were conducted to investigate the influence of the main loading parameters,including confining pressure,vibration frequency,and static force,on the damage of granite *** individual and combined influences were analyzed according to the porosity increase and P-wave decrease of granite specimens using the variance analysis *** results show that the combined effect of the static force and vibration frequency mainly promotes fatigue damage of specimens,that the confining pressure determines the damage behaviour and failure mode of specimens under ultrasonic vibration,and that the confining pressure and vibration frequency are the main factors that cause the fracture concentration in the upper part of specimens,an effect mechanistically driven by the obvious load energy *** research results provide theoretical guidance for the application of ultrasonic vibration technology.

关键词： Ultrasonic vibration Granite Damage evolution Confining pressure Vibration frequency Static force Combined effect

SAR image water extraction using the attention U-net and multi-scale level set method:flood monitoring in South China in 2020 as a test case

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Geo-Spatial Information Science 2022年第2期25卷 155-168页

作者： Chuan Xu Shanshan Zhang Bofei Zhao Chang Liu Haigang Sui Wei Yang Liye Mei School of Computer Science Hubei University of TechnologyWuhanChina Geographic Information Center GuangZhou Urban Planning&Design Survey Research InstituteGuangzhouChina State Key Laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina School of Information Science and Engineering Wuchang Shouyi UniversityWuhanChina The institute of Technological Sciences Wuhan UniversityWuhanChina

Level set method has been extensively used for image segmentation,which is a key technology of water ***,one of the problems of the level-set method is how to find the appropriate initial surface parameters,which will affect the accuracy and speed of level set ***,the semantic segmentation based on deep learning has opened the exciting research *** addition,the Convolutional Neural Network(CNN)has shown a strong feature representation ***,in this paper,the CNN method is used to obtain the initial SAR image segmentation map to provide deep a priori information for the zero-level set curve,which only needs to describe the general outline of the water body,rather than the accurate *** with the traditional circular and rectangular zero-level set initialization method,this method can converge to the edge of the water body faster and more precisely;it will not fall into the local minimum value and be able to obtain accurate segmentation *** effectiveness of the proposed method is demonstrated by the experimental results of flood disaster monitoring in South China in 2020.

关键词： Water extraction flood monitoring level set attention U-net Convolutional Neural Network(CNN)

Distribution, failure risk and reinforcement necessity of check-dams on the Loess Plateau: a review

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Journal of Mountain Science 2021年第2期18卷 499-509页

作者： GUO Wen-zhao WANG Wen-Long XU Qiang HU Jian-jun ZHU Li-li State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Water and Soil ConservationNorthwest A&F UniversityYangling 712100China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610059China Xi'an Planning Design&Research InstituteUpper and middle Yellow River BureauYellow River Conservancy CommissionMinistry of Water ResourcesXi'an 710021China

Check-dams are the most important measure to control the soil and water loss in highly erodible catchments on the Chinese Loess *** on the data of check-dams from 1950 to 2014,our study roundly analyzed the regional distribution,function and the problems of check-dams on the Loess Plateau.A total of 17,094 check-dams with a storage capacity of over 100,000 m^(3) and an average density of 0.027 counts km^(-2) were installed on the Loess ***-dams’densities varied greatly in the Qinghai province,Gansu province,Ningxia Hui Autonomous Region,Inner Mongolia Autonomous Region,Shaanxi province,Shanxi province and henan *** highest density of check-dams reached 0.088 counts km^(-2) in Shaanxi province,whereas the lowest density of check-dams was only 0.005 counts km^(-2) in Qinghai ***,after decades of operation,3025 large check-dams and 2257 medium check dams are dangerous and have security risks,which are seriously threatening downstream *** dangerous rate of checkdams is ***,the check-dams in Shanxi and Qinghai province have the highest dangerous rates,with both exceeding 53%.Therefore,there is an urgent need for carrying out reinforcement of the dangerous *** results are helpful to policymakers to extend and develop check-dams.

关键词： Check-dam Soil erosion Sediment Gully Dam failure Chinese Loess Plateau