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Variability of urban fractional vegetation cover and its driving factors in 328 cities in China

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Science China Earth Sciences 2024年第2期67卷 466-482页

作者： fei FENG Xin YANG Baoquan JIA Xiaoting li Xianwen li Chengyang XU Kaicun WANG Research Centre of Urban Forestry Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland AdministrationBeijing Forestry UniversityBeijing100083China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Research Institute of Forestry Chinese Academy of ForestryBeijing100091China School of Architecture Tsinghua UniversityBeijing100084China College of Urban and Environmental Sciences Sino-French Institute for Earth System ScienceInstitute of Carbon NeutralityPeking UniversityBeijing100871China

Urban green space promotes the health of urban residents,enhances urban ecosystem biodiversity,mitigates environmental pollution,and attenuates urban heat island ***,urban vegetation cover is highly heterogeneous and difficult to *** this study,the variation of urban fractional vegetation cover(FVC)in 328 cities in China from 1990 to2022 was quantified based on Landsat satellite data at a 30-m *** was found that from 1990 to 2005,due to increases in building density and impervious surfaces in cities,the national mean urban vegetation cover decreased from 0.38 to ***2005,urban vegetation cover began to reverse,reaching 0.45 in *** increasing trend was most pronounced in newly built urban *** decrease in average urban vegetation cover before 2005 was mainly due to the expansion of low vegetation cover areas,while the increase in urban vegetation cover after 2005 manifested as the expansion of high vegetation cover *** reversal in the trend of urban vegetation cover change after 2004 is related to the gradual implementation of national policies requiring increased urban green space *** urban gross domestic product(GDP)showed the highest correlation with changes in urban vegetation *** large and medium-sized cities,the top three factors influencing vegetation cover were GDP,urban population,and ***,for cities in arid/semi-arid regions,changes in vegetation cover were more sensitive to climatic factors(such as precipitation).Although the urban vegetation cover in China has substantially increased in recent years,the urban green space in small-sized cities and in the old urban districts of large-sized cities still have room to improve.

关键词： Urban vegetation Urban vegetation cover Urbanization Remote sensing

Reshaping force for deformed casing repairing with hydraulic rolling reshaper and its influencing factors

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Petroleum Science 2024年第4期21卷 2745-2757页

作者： Hong-fei li Min Luo Ting-Ting Xu Qiao-Zhen li Cong-Jian Huang School of Mechanical Science and Engineering Northeast Petroleum University

Hydraulic rolling reshaper is an advanced reshaping tool to solve the problem of casing deformation,which has been widely used in recent years. When it is used for well repair operation, the reshaping force provided by ground devices is generally determined by experience. However, too large reshaping force may destroy the deformed casing, and too small reshaping force may also prolong the construction period and affect the repairing effect. In this paper, based on Hertz contact theory and elastic-plastic theory, combined with the process parameters of shaping, and considering the structural characteristics of the deformed casing and reshaper, we propose a mathematical model for calculating the reshaping force required for repairing deformed casing by hydraulic rolling reshaper. Meanwhile, the finite element model and numerical method of hydraulic rolling reshaper repairing deformed casing are established by using the finite element method, and the reliability of the mathematical model is verified by several examples. On this basis, the control variable method is used to investigate the influence of each parameter on the reshaping force, and the influence degree of each parameter is explored by orthogonal simulation test and Pearson correlation analysis. The research results not only provide an important theoretical basis for the prediction of reshaping force in on-site construction, but also provide a reference for the subsequent improvement of the shaping process.

关键词： Hydraulic rolling reshaper Reshaping force Deformed casing Casing reshaping Hertz contact theory

Performance Study of the MPC based on BPNN Prediction Model in Thermal Management System of Battery Electric Vehicles

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Journal of Thermal Science 2024年第6期33卷 2318-2335页

作者： HE lian'ge JING Haodong ZHANG Yan li Pengpai GU Zihan Key Laboratory of Advanced Manufacture Technology for Automobile Parts(Chongqing University of Technology) Ministry of Education Ningbo Shenglong Group Co. Ltd. Chongqing Tsingshan Industrial Co. Ltd.

In this paper,a model predictive control(MPC) based on back propagation neural network(BPNN)prediction model was proposed for compressor speed control of air conditioning system(ACS) and battery thermal management system(BTMS) coupling system of battery electric vehicle(BEV).In order to solve the problem of high cooling energy consumption and inferior thermal comfort in the cabin of the battery electric vehicle thermal management system(BEVTMS) during summer time,this paper combines the respective superiorities of artificial neural network(ANN) predictive modeling and MPC,and creatively combines the two methods and uses them in the control of ***,based on ANN and heat transfer theory,BPNN prediction model,ACS and BTMS coupling system were established and ***,a mathematical method of MPC was established to control the speed of the ***,the state parameters of the coupled system were predicted using a BPNN prediction model,and the predicted values were passed to the MPC,thus achieving accurate control of the compressor speed using the ***,the effects of PID control and MPC based on BPNN prediction model on thermal comfort of cabin and compressor energy consumption at different ambient temperatures were compared in simulation under New European Driving Cycle(NEDC) *** results showed for the constructed BPNN prediction model predicted and tested values of the selected parameters the mean squared error(MSE) ranged from 2.498% to 8.969%,mean absolute percentage error(MAPE) ranged from 4.197% to 8.986%,and mean absolute error(MAE) ranged from 3.202% to 8.476%.At ambient temperatures of 25℃,35℃ and 45℃,the MPC based on the BPNN prediction model reduced the cumulative discomfort time in the cabin by 100 s,39 s and 19 s,respectively,compared with the PID *** three NEDC conditions,the energy consumption is reduced by 1.82%,2.35% and 3.48%,*** the ambient temperature was 35℃,the MPC based on BPNN pre

关键词： air conditioning system back propagation neural network battery electric vehicle battery thermal management system model predictive control

Storage, form, and influencing factors of karst inorganic carbon in a carbonate area in China

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Science China Earth Sciences 2024年第3期67卷 725-739页

作者： Chaochao DU Xiaoyong BAI Yangbing li Qiu TAN Cuiwei ZHAO Guangjie LUO Luhua WU fei CHEN Chaojun li Chen RAN Sirui ZHANG lian XIONG Fengjiao SONG Biqin XIAO Zilin li Yingying XUE Mingkang LONG Qing LUO Xiaoyun ZHANG Minghui li Xiaoqian SHEN Shu YANG State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China School of Geography and Environmental Sciences Guizhou Normal UniversityGuiyang 550001China CAS Center for Excellence in Quaternary Science and Global Change Xi'an 710061China Guizhou Provincial Key Laboratory of Geographic State Monitoring of Watershed Guizhou Normal CollegeGuiyang 550018China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China

Carbonate rock chemical weathering carbon sinks reduce the rate of increase of the atmospheric CO_(2) concentration and global warming. However, uncertainty still exists in the estimation results of carbonate rock chemical weathering carbon sink fluxes(CCSF), and the contributions of climate change and ecological restoration to the CCSF are not clear. To this end, we compiled published site data on ion concentrations in different watersheds in China and used a classical thermodynamic dissolution model to reassess the potential and spatial and temporal patterns of the CCSF in China from 1991 to 2020. We quantified the contributions of temperature(MAT), precipitation(MAP), evapotranspiration(ET), soil water(SM), and the normalized difference vegetation index(NDVI) to the CCSF. The results revealed that(1) China's CCSF was 22.76 t CO_(2)km^(-2)yr^(-1), which was higher than the global average(15.77 t CO_(2)km^(-2)yr^(-1)). The total carbonate rock chemical weathering carbon sink(CCS) was 4772.67×10^(4)t CO_(2), contributing 14.91% of the global CCS through a carbonate rock area of 252.98×10^(4)km^(-2).(2) China's CCSF decreased gradually from southeast to northwest, with values of 33.14, 12.93, and7.27 t CO_(2)km^(-2)yr^(-1)in the southern karst, Qinghai-Tibetan karst, and northern karst regions, respectively.(3) The overall CCSF in China exhibited an increasing trend from 1991 to 2020, with a rate of increase of 0.16 t CO_(2)km^(-2)yr^(-1).(4) The contributions of the MAP, MAT, ET, SM, and NDVI to the CCSF were 63.3%, 3.02%, 27.5%, 3.1%, and 3.05%, respectively. Among them, the increase in precipitation was the main contributor to the increase in the CCSF in China over the last 30 years, while the enhancement of ET offset part of the positive contribution of the increase in precipitation to the CCSF. In conclusion, the results of this study provide a systematic quantification of the magnitude, the patterns, and the influencing factors of CCS over a long time series in

关键词： Carbonate rocks Carbon sinks Patterns Influencing factors Thermodynamic dissolution modeling

Zooplankton community response to eddy during dinoflagellate Noctiluca scintillans blooms off Pakistan,northern Arabian Sea

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Journal of Oceanology and limnology 2024年第5期42卷 1557-1570页

作者： Mahugnon Boris DEDO Xiping lian Kaizhi li Chenhui XIANG Yehui TAN Key Laboratory of Tropical Marine Bioresources and Ecology Guangdong Provincial Key Laboratory of Applied Marine BiologySouth China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China University of Chinese Academy of Sciences Beijing 100049China Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of Sciences(ISEECAS)Guangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 510301China

Eddies are major elements of ocean dynamics that affect ocean *** their effects on plankton distribution may help understand the dynamics of harmful phytoplankton *** studies on the effects of eddies in the northern Arabian Sea have primarily focused on the zooplankton community,and few have observed zooplankton dynamics during winter blooms of Noctiluca *** investigated zooplankton community structure and the related environmental variability during a *** bloom that was affected by an eddy in February *** sampling stations were deployed at eddy core and eddy edge distinguished in salinity,temperature,and *** show that *** bloomed at the eddy core with high-velocity currents induced by warm eddies that moved from eddy core to eddy *** a result,blooms significantly changed the zooplankton community ***-bloom stations had higher zooplankton diversity than bloom *** at non-bloom stations were dominated by either tunicates or copepods,such as Thalia democratica and Pleuromamma *** addition to the influence of *** blooms,the velocity of eddy currents was a crucial factor on the similarities in the zooplankton community composition between eddy edge and eddy ***,the lower abiotic factors in bloom area contribute to the structuring of the zooplankton community during *** blooms.

关键词： eddy zooplankton community Noctiluca scintillans northern Arabian Sea

A giant Ce-containing poly(tungstobismuthate): Synthesis, structure and catalytic performance for the decontamination of a sulfur mustard simulant

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Chinese Chemical Letters 2024年第10期35卷 465-468页

作者： Chen lian Si-Han Zhao Hai-Lou li Xinhua Cao College of Chemistry and Chemical Engineering Xinyang Normal UniversityXinyang 464000China MOE Key Laboratory of Cluster Science School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 102488China

A novel Ce-containing poly(tungstobismuthate)Cs18Na8H_(2)0[Ce3(H_(2)O)10W8Bi4O_(2)8(B-α-Bi W9O_(3)3)4]2·64H_(2)O(1)has been synthesized by a facile one-pot self-assembly reaction *** structural characterization is realized by virtue of single-crystal X-ray diffraction,infrared spectroscopy,powder X-ray diffraction and thermogravimetric *** polyoxoanion of 1 is an octameric architecture consisting of two tetrameric entities[Ce3(H_(2)O)10W8Bi4O_(2)8(B-α-Bi W9O_(3)3)4]23-linked by two Ce–O–W bonds,and adjacent polyoxoanions are further combined together by means of Ce3+linkers,resulting in an infinite 1D chain *** 1 is the currently largest tungstobismuthate,and also represents the first example of lanthanide-encapsulated tungstobismuthate exhibiting an extended ***,compound 1 as a heterogeneous catalyst,exhibits high activity for the oxidative decontamination of a sulfur mustard simulant,2-chloroethyl ethyl sulfide(CEES)into 2-chloroethyl ethyl sulfoxide(CEESO).

关键词： Polyoxometalates Tungstobismuthate Cluster Lanthanide Oxidation

A high-resolution dataset for lower atmospheric process studies over the Tibetan Plateau from 1981 to 2020

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Big Earth Data 2024年第3期8卷 540-565页

作者： fei li Shupo Ma Jinhuan Zhu Han Zou Peng li libo Zhou Department of Lower Atmospheric Observation Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina

ABSTRACT A high-resolution meteorological dataset(≤10 km)over the Tibetan Plateau(TP)is the foundation for investigating and predicting the weather and climate over *** TP Subregional Dynamical Downscaling(TPSDD)dataset is a newly developed high-spatial-temporal resolution gridded dataset for land‒air exchange pro-cesses and lower atmospheric structure studies over the whole TP region,taking the climate characteristics of each TP subregion into *** dataset spans from 1981 to 2020,covering the TP with a temporal resolution of 2 hr and spatial resolution of 10 *** elements of the dataset include near-surface land-air exchange parameters,such as downward/upward long-wave/shortwave radiation flux,sensible heat flux,latent heat flux,*** addition,the vertical distributions of 3-dimensional wind,temperature,humidity,and pressure from the surface to the lower stratosphere are also *** evaluations were con-ducted to verify the performance of the TPSDD dataset by compar-ing TPSDD/reanalysis with surface and vertical observations through the calculation of statistical *** results demonstrate the accuracy and superiority of this dataset against reanalysis data,which provides great potential for future climate change research.

关键词： Tibetan Plateau WRF model dynamical downscaling land‒air interaction the lower atmosphere

DeepGCN based on variable multi‐graph and multimodal data for ASD diagnosis

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 879-893页

作者： Shuaiqi liu Siqi Wang Chaolei Sun Bing li Shuihua Wang fei li College of Electronic and Information Engineering Hebei UniversityBaodingChina Machine Vision Technology Innovation Center of Hebei Province BaodingChina The State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijingChina School of Computer Science and Technology Henan Polytechnic UniversityJiaozuoChina

Diagnosing individuals with autism spectrum disorder(ASD)accurately faces great chal-lenges in clinical practice,primarily due to the data's high heterogeneity and limited sample *** tackle this issue,the authors constructed a deep graph convolutional network(GCN)based on variable multi‐graph and multimodal data(VMM‐DGCN)for ASD ***,the functional connectivity matrix was constructed to extract primary ***,the authors constructed a variable multi‐graph construction strategy to capture the multi‐scale feature representations of each subject by utilising convolutional filters with varying kernel ***,the authors brought the non‐imaging in-formation into the feature representation at each scale and constructed multiple population graphs based on multimodal data by fully considering the correlation between *** extracting the deeper features of population graphs using the deep GCN(DeepGCN),the authors fused the node features of multiple subgraphs to perform node classification tasks for typical control and ASD *** proposed algorithm was evaluated on the Autism Brain Imaging Data Exchange I(ABIDE I)dataset,achieving an accuracy of 91.62%and an area under the curve value of 95.74%.These results demon-strated its outstanding performance compared to other ASD diagnostic algorithms.

关键词： machine learning medical image processing medical signal processing

Hole-Transporting Materials with Rational Combination of Pyridine and Dibenzo[a,c]phenazine as Electron Acceptor for Dopant-Free Perovskite Solar Cells

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Chinese Journal of Chemistry 2024年第10期42卷 1100-1106页

作者： Weidong ling fei Wu Wentao Yuan linna Zhu Qianqian li Zhen li Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Department of ChemistryWuhan UniversityWuhanHubei 430072China Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energy Faculty of Materials&EnergySouthwest UniversityChongqing400715China TaiKang Center for life and Medical Sciences Wuhan UniversityWuhanHubei 430072China

Perovskite solar cells(PSCs)have been proven to be a promising option for photovoltaic *** the aim to achieve efficient and stable PSCs,it is essential to explore dopant-free hole-transporting materials(HTMs)with high hole ***,HTMs bearing electron donor(D)-electron acceptor(A)-electron donor(D)structures have been constructed with strong intramolecular charge transfer(ICT)effect,based on rational combination of dibenzo[a,c]phenazine and pyridine as electronic acceptors and anchoring groups to perovskite ***,high hole mobility(7.31×10^(-5) cm^(2)·V^(-1)·s^(-1))and photoelectric conversion efficiency(20.45%)have been achieved by dopant-free DPyP-based *** afforded an efficient way to design HTMs with high hole mobility by adjustment of molecular configurations and electronic property of conjugated systems.

关键词： Perovskite solar cell Charge transfer Donor-acceptor systems Energy conversion Hole mobility