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Dynamic evolution of spring sand and dust storms and cross-border response in Mongolian plateau from 2000 to 2021

International Journal of Digital Earth 2023年第1期16卷 2341-2355页

作者： Yu Zhang Juanle Wang Altansukh Ochir Sonomdagva Chonokhuu Chuluun Togtokh State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China College of Geoscience and Surveying Engineering China University of Mining&Technology(Beijing)BeijingPeople’s Republic of China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application NanjingPeople’s Republic of China Environmental Engineering Laboratory Department of Environment and Forest EngineeringSchool of Engineering and Applied Sciences and Institute for Sustainable DevelopmentNational University of MongoliaUlaanbaatarMongolia Department of Environment and Forest Engineering National University of MongoliaUlaanbaatar CityMongolia Institute for Sustainable Development National University of MongoliaUlaanbaatarMongolia

According to the United Nations Sustainable Development Goals(SDG 15.3),frequent sand and dust storms(SDSs)in the spring are a long-term challenge to the prevention and control of land degradation on the Mongolian *** this study,MODIS remote sensing data are used to monitor and analyse SDS events on the Mongolian *** annual distribution of spring SDSs(March to May)from 2000 to 2021 are obtained based on the dust storm detection *** overall classification accuracy is 85.24%and the kappa coefficient is *** show a decrease in the overall frequency of SDS events,where storm events in 2000–2010 are significantly higher than those in the second *** cross-border regions between China and Mongolia appear to be SDS intensity centers,particularly those in southern *** exhibits a strong negative correlation with the area affected by SDS,and the correlation coefficient is–*** increase in barren and sand contributes primarily to the increase in SDS,whereas wind prevention and sand control projects undertaken by the Mongolian and Chinese governments promote regional *** pertaining to cross-board sandstorm responses on the Mongolian Plateau are recommended.

关键词： Mongolian plateau dust storm dust index land degradation MODIS

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Machine learning for membrane bioreactor research:principles,methods,applications,and a tutorial

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Frontiers of Environmental Science & engineering 2025年第3期19卷 119-144页

作者： Yizhe Lai Kang Xiao Yifan He Xian Liu Jihua Tan Wenchao Xue Aiqian Zhang Xia Huang Beijing Yanshan Earth Critical Zone National Research Station College of Resources and EnvironmentUniversity of Chinese Academy of SciencesBeijing 101408China Key Laboratory of Earth System Numerical Modeling and Application University of Chinese Academy of SciencesBeijing 101408China Environmental Chemistry Faculty College of Resources and EnvironmentUniversity of Chinese Academy of SciencesBeijing 101408China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Department of Energy Environmentand Climate ChangeSchool of EnvironmentResourcesand DevelopmentAsian Institute of TechnologyP.O.Box 4Klong LuangPathumthani 12120Thailand State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China

Membrane fouling poses a significant challenge to the sustainable development of membrane bioreactor(MBR)technologies for wastewater *** accurate prediction of the membrane filtration process is of great importance for identifying and controlling *** learning methods address the limitations of traditional statistical approaches,such as low accuracy,poor generalization ability,and slow convergence,particularly in predicting complex filtration and fouling processes within the realm of big *** article provides an in-depth exposition of machine learning *** study then reviews advances in MBRs that utilize machine learning methods,including artificial neural networks(ANN),support vector machines(SVM),decision trees,and ensemble *** on current literature,this study summarizes and compares the model input and output characteristics(including foulant characteristics,solution environments,filtration conditions,operating conditions,and time factors),as well as the selection of models and optimization *** modeling procedures of SVM,random forest(RF),back propagation neural network(BPNN),long short-term memory(LSTM),and genetic algorithm-back propagation(GA-BP)methods are elucidated through a tutorial *** simulation results demonstrated that all five methods yielded accurate predictions with R2>***,the existing challenges in the implementation of machine learning models in MBRs were *** is notable that integration of deep learning,automated machine learning(AutoML)and explainable artificial intelligence(XAI)may facilitate the deployment of models in practical engineering *** insights presented here are expected to facilitate the establishment of an intelligent control framework for MBR processes in future endeavors.

关键词： Membrane bioreactor Machine learning Pollutant removal Membrane fouling Model prediction

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Dissecting the contributions of organic nitrogen aerosols to global atmospheric nitrogen deposition and implications for ecosystems

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national Science Review 2023年第12期10卷 124-136页

作者： Yumin Li Tzung-May Fu Jian Zhen Yu Xu Yu Qi Chen Ruqian Miao Yang Zhou Aoxing Zhang Jianhuai Ye Xin Yang Shu Tao Hongbin Liu Weiqi Yao Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks School of Environmental Science and Engineering Southern University of Science and Technology Guangdong Provincial Observation and Research Station for Coastal Atmosphere and Climate of the Greater Bay Area Southern University of Science and Technology Division of Environment and Sustainability Hong Kong University of Science and Technology National Center for Applied Mathematics Shenzhen Department of Chemistry Hong Kong University of Science and Technology State Key Joint Laboratory of Environmental Simulation and Pollution Control International Joint Laboratory for Regional Pollution Control College of Environmental Sciences and Engineering Peking University Frontier Science Center for Deep Ocean Multispheres and Earth System and Physical Oceanography Laboratory Ocean University of China College of Oceanic and Atmospheric Sciences Ocean University of China Department of Ocean Science Hong Kong University of Science and Technology Department of Ocean Science and Engineering Southern University of Science and Technology

Atmospheric deposition of particulate organic nitrogen（ONp） is a significant process in the global nitrogen cycle and may be pivotally important for N-limited ***,past models largely overlo oked the spatial and chemical inhomogeneity of atmospheric ONpand were thus deficient in assessing global *** constructed a comprehensive global model of atmospheric gaseous and particulate organic nitrogen（ON）,including the latest knowledge on emissions and secondary *** this model,we simulated global atmospheric ONpabundances consistent with *** estimated global atmospheric ON deposition was 26 Tg N yr-1,predominantly in the form of ONp(23 Tg N yr-1)and mostly from wildfires（37%）,oceans（22%） and aqueous productions（17%）.Globally,ONpcontributed as much as 40% to 80% of the total N deposition downwind of biomass-burning *** ONpdeposition thus constituted the dominant external N supply to the N-limited boreal forests,tundras and the Arctic Ocean,and its importance maybe amplified in a future warming climate.

关键词： organic nitrogen aerosol secondary organic nitrogen biomass burning

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Paired regions for shadow removal approach based on multi-features

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High technology Letters 2023年第2期29卷 174-180页

作者：张之政 GUO Mingqiang WU Liang HUANG Ying CHEN Xueye Key Laboratory of Urban Land Resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen 518034P.R.China National Engineering Research Center of Geographic Information System China University of GeosciencesWuhan 430074P.R.China School of Computer Science China University of GeosciencesWuhan 430074P.R.China Wuhan Zondy Cyber Technology Co. Ltd.Wuhan 430074P.R.China

The existence of shadow leads to the degradation of the image qualities and the defect of ground object *** removal is therefore an essential research topic in image processing *** biggest challenge of shadow removal is how to restore the content of shadow areas correctly while removing the shadow in the *** regions for shadow removal approach based on multi-features is proposed, in which shadow removal is only performed on related sunlit *** distance between regions is calculated to find the optimal paired regions with considering of multi-features(texture, gradient feature, etc.) *** in different scenes with peak signal-to-noise ratio(PSNR) and structural similarity(SSIM) evaluation indexes are chosen for *** results are shown with six existing comparison methods by visual and quantitative assessments, which verified that the proposed method shows excellent shadow removal effect, the brightness, color of the removed shadow area, and the surrounding non-shadow area can be naturally fused.

关键词： paired region feature distance texture peak signal-to-noise ratio(PSNR) structural similarity(SSIM)

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Two-Stage OD Flow Prediction for Emergency in Urban Rail Transit

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IEEE Transactions on Intelligent Transportation systems 2024年第1期25卷 920-928页

作者： Zhu, Guangyu Ding, Jiacun Wei, Yun Yi, Yang Xu, Sendren Sheng-Dong Wu, Edmond Q. Beijing Jiaotong University Key Lab. of Transport Industry of Big Data Application Technologies for Comprehensive Transport The Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Beijing100044 China Beijing Mass Transit Railway Operation Corporation Ltd. Beijing100014 China Yangzhou University College of Information Engineering Yangzhou225127 China National Taiwan University of Science and Technology Automation and Control Center The Graduate Institute of Automation and Control Taipei106335 Taiwan Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education of China The Shanghai Engineering Research Center of Intelligent Control and Management Department of Automation Shanghai200240 China

Urban rail transit (URT) is vulnerable to natural disasters and social emergencies including fire, storm and epidemic (such as COVID-19), and real-time origin-destination (OD) flow prediction provides URT operators with important information to ensure the safety of URT system. However, hindered by the high dimensionality of OD flow and the lack of supportive information reflecting the real-time passenger flow changes, study in this area is at the beginning stage. A novel model consisting of two stages is proposed for OD flow prediction. The first stage predicts the inflows of all stations by Long Short-Term Memory (LSTM) in real time, where the dimension is reduced compared with predicting OD flows directly. In the second stage, the notion of separation rate, namely, the proportion of inbound passengers bounding for another station, is estimated. Finally, The OD flow is predicted by multiplying the inflow and separation rate. Experiments based on Hangzhou Metro dataset show the proposed model outperforms the contrast model in weighted mean average error (WMAE) and weighted mean square error (WMSE). Results also suggest that the proposed prediction model performs better on weekdays than on weekends, and with greater accuracy on larger OD flows. © 2000-2011 IEEE.

关键词： Forecasting

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Deciphering decadal urban ozone trends from historical records since 1980

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national Science Review 2024年第11期11卷 117-129页

作者： Haolin Wang Xiao Lu Paul I.Palmer Lin Zhang Keding Lu Ke Li Tatsuya Nagashima Ja-Ho Koo Hiroshi Tanimoto Haichao Wang Meng Gao Cheng He Kai Wu Shaojia Fan Yuanhang Zhang School of Atmospheric Sciences Sun Yat-sen University and Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Education Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) School of Geo Sciences University of Edinburgh National Centre for Earth Observation University of Edinburgh Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University State Key Joint Laboratory of Environmental Simulation and Pollution Control The State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution ControlCollege of Environmental Sciences and Engineering Peking University Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science &Technology National Institute for Environmental Studies Department of Atmospheric Sciences Yonsei University Department of Geography Hong Kong Baptist University Department of Civil and Environmental Engineering University of California

Ozone pollution is a major environmental threat to human health. Timely assessment of ozone trends is crucial for informing environmental policy. Here we show that for the most recent decade（2013–2022） in the northern hemisphere, warm-season（April–September） mean daily 8-h average maximum ozone increases much faster in urban regions with top ozone levels(mainly in the North China Plain, 1.2 ± 1.3 ppbv year-1) than in other, low-ozone regions(0.2 ± 0.9 ppbv year-1). These trends widen the ozone differences across urban regions, and increase extreme pollution levels and health threats from a global perspective. Comparison of historical trends in different urban regions reveals that ozone increases in China during 2013–2022 differ in magnitude and mechanisms to historical periods in other regions since *** reflects a unique chemical environment characterized by exceptionally high nitrogen oxides and aerosol concentrations, where reducing ozone precursor emissions leads to substantial ozone *** increase in China has slowed down in 2018–2022 compared to 2013–2017, driven by ongoing emission reductions, but with ozone-favorable weather conditions. Historical ozone evolution in Japan and South Korea indicates that ozone increases should be suppressed with continuous emission *** temperature and associated wildfires have also reversed ozone decreases in the USA and Europe,with anthropogenic ozone control slowing down in recent decades.

关键词： air quality surface ozone trends

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Mathematical modeling and numerical computation of the effective interfacial conditions for Stokes flow on an arbitrarily rough solid surface

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 721-746页

作者： A.T.TRAN H.LE QUANG Q.C.HE D.H.NGUYEN Research and Application Center for Technology in Civil Engineering University of Transport and CommunicationsHanoi 10000Vietnam Laboratoire Modelisation et Simulation Multi-Echelle Unite Mixte de Recherche 8208Centre National de la Recherche ScientifiqueUniversite Gustave EiffelMarne-la-Vallee F-77454France School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China

The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid *** distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily *** main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip *** solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly *** results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the *** comparison shows that the two proposed methods are particularly efficient and accurate.

关键词： effective slip length method of fundamental solution(MFS) boundary element method(BEM) Stokeslet micro-channel fluid/solid interface

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Health benefits from the rapid reduction in ambient exposure to air pollutants after China's clean air actions:progress in efficacy and geographic equality

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national Science Review 2024年第2期11卷 103-113页

作者： Tao Xue Ruohan Wang Meng Wang Yanying Wang Dan Tong Xia Meng Conghong Huang Siqi Ai Fangzhou Li Jingyuan Cao Mingkun Tong Xueqiu Ni Hengyi Liu Jianyu Deng Hong Lu Wei Wan Jicheng Gong Shiqiu Zhang Tong Zhu Institute of Reproductive and Child Health National Health Commission Key Laboratory of Reproductive Health/Department of Epidemiology and Biostatistics Ministry of Education Key Laboratory of Epidemiology of Major Diseases(PKU) School of Public Health Peking University Health Science Centre State Environmental Protection Key Laboratory of Atmospheric Exposure and Health Risk Management and Center for Environment and Health Peking University Advanced Institute of Information Technology Peking University Department of Epidemiology and Environmental Health School of Public Health and Health ProfessionsUniversity at Buffalo State Key Joint Laboratory of Environment Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking University Department of Earth System Science Tsinghua University School of Public Health Key Laboratory of Public Health Safety of the Ministry of Education and Key Laboratory of Health Technology Assessment of the Ministry of HealthFudan University College of Land Management Nanjing Agricultural University National&Local Joint Engineering Research Center for Rural Land Resources Use and Consolidation Clean Air Asia

Clean air actions （CAAs） in China have been linked to considerable benefits in public ***,whether the beneficial effects of CAAs are equally distributed geographically is *** high-resolution maps of the distributions of major air pollutants (fine particulate matter[PM2.5]and ozone[O3]) and population,we aimed to track spatiotemporal changes in health impacts from,and geographic inequality embedded in,the reduced exposures to PM2.5and O3from 2013 to *** used a method established by the Global Burden of Diseases *** analyzing the changes in loss of life expectancy（LLE） attributable to PM2.5and O3,we calculated the gain of life expectancy （GLE） to quantify the health benefits of the air-quality ***,we assessed the geographic inequality embedded in the GLE using the Gini index （GI）.Based on risk assessments of PM2.5and O3,during the first stage of CAAs（2013 to 2017）,the mean GLE was 1.87 *** of the sum of the GLE was disproportionally distributed in about one quarter of the population exposed （GI 0.44）.During the second stage of CAAs（2017 to 2020）,the mean GLE increased to 3.94 months and geographic inequality decreased （GI 0.18）.According to our assessments,CAAs were enhanced,from the first to second stages,in terms of not only preventing premature mortality but also ameliorating health *** enhancements were related to increased sensitivity to the health effects of air pollution and synergic control of PM2.5and *** findings will contribute to optimizing future CAAs.

关键词： clean air action public health inequality fine particulate matter ozone

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GENETIC ALGORITHM-BASED CONSTELLATION ORBIT DESIGN FOR EFFICIENT INTEGRATED OPERATION OF SINGLE SATELLITES AND INCREASE OF THE TEMPORAL RESOLUTION OF SATELLITE INFORMATION 73

GENETIC ALGORITHM-BASED CONSTELLATION ORBIT DESIGN FOR EFFIC...

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73rd International Astronautical Congress, IAC 2022

作者： Jung, Insik Chung, Dae-Won Lee, Samyoung Shin, Seungmin Kim, Dongjin Lee, Kimoon Department of Aerospace System Engineering University of Science and Technology 217 Gajeong-ro Yuseong-gu Daejeon34113 Korea Republic of National Satellite Operations & Application Center Korea Aerospace Research Institute 169-84 Gwahak-ro Yuseong-gu Daejeon34133 Korea Republic of

Fusing the satellite information obtained from multiple satellites can bring various advantages, and one of them is that satellite information can be acquired in a timely manner. While each single satellite in operation can image a specific area once or twice a day, if each satellite is operated as one constellation, the frequency of imaging for a specific area can be increased several times or more. Satellite information with various temporal-spatial resolutions obtained from various sensors can be used image fusion in various fields such as disaster monitoring including forest, fires, droughts and etc., as well as reconnaissance and resource exploration. But each single satellite developed individually has optimized orbits according to the sensor characteristics, the integrated operation of each satellite as it should have a low temporal resolution. In this paper, a method for designing a constellation orbit using a genetic algorithm is introduced in order to ensure that various satellite information acquired through integrated operation of existing single satellites and single satellites to be launched in the future can have high temporal resolution. Only the RAAN of the satellite to be launched in the future was considered to optimize the revisit characteristics for a specific area in order to minimize the effect on the sensors of each satellite and the change of the orbit of the already operating satellites. The fitness functions of genetic algorithm were applied differently for the optical and SAR satellite since the available imaging time is different. In case of optical satellites, considering that imaging is possible only during day time, the fitness function was set so that the available imaging time for a specific area could be concentrated during the day time. Since the SAR satellites do not have any restrictions on the available imaging time, the fitness function was set to so that the revisit time is evenly distributed. The result show that the revisit

关键词： Satellites

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1.8 W, high efficiency, pump-enhanced, narrow linewidth optical parametric oscillator at 3.8 μm

1.8 W, high efficiency, pump-enhanced, narrow linewidth opti...

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作者： Zhao, Gang Tan, Wei Liu, Gaoyou Li, Chen Hu, Qiongyu Guo, Quanxin Zhao, Zhigang Liu, Zhaojun School of Information Science and Engineering Shandong University Qingdao266237 China Key Laboratory of Time and Frequency Primary Standards National Time Service Center Chinese Academy of Sciences Xi'an710600 China Shandong Provincial Key Laboratory of Laser Technology and Application Qingdao266237 China Key Laboratory of Laser & Infrared System Shandong University Ministry of Education Qingdao266237 China Center for Optics Research and Engineering Shandong University Qingdao266237 China

A high efficiency, continuous-wave, narrow linewidth, pump-enhanced optical parametric oscillator (OPO) at 3.8 μm was demonstrated, which was pumped by a 1064 nm fiber laser with a linewidth of 18 kHz. The low frequency modulation locking technique was employed to stabilize the output power. The wavelengths of signal and idler were 1475.5 nm and 3819.9 nm at 25 °C, respectively. The pump-enhanced structure was applied, leading to a maximum quantum efficiency of over 60% with pump power of 3W. The maximum output power of idler light is 1.8 W with a linewidth of 363 kHz. The excellent tuning performance of the OPO was also demonstrated. In order to avoid mode-splitting and decrease of pump enhancing factor due to feedback light in the cavity, the crystal was placed obliquely to the pump beam and the maximum output power was increased by 19%. At the maximum output power of idler light, the M2 factors in the x and y directions were 1.30 and 1.33, respectively. © 2023 Optica Publishing Group.

关键词： Optical parametric oscillators

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