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Impacts of meteorology and emission variations on the heavy air pollution episode in North China around the 2020 Spring Festival

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Science China Earth Sciences 2021年第2期64卷 329-339页

作者： Wenbo XUE Xurong SHI Gang YAN Jinnan WANG Yanling XU Qian TANG Yanli WANG Yixuan ZHENG Yu LEI Center of air Modeling and Systems Analysis Chinese Academy for Environmental PlanningBeijing 100012China State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy for Environmental PlanningBeijing 100012China

Based on the Weather Research and Forecasting model and the Models-3 community multi-scale air quality model(WRF-CMAQ),this study analyzes the impacts of meteorological conditions and changes in air pollutant emissions on the heavy air pollution episode occurred over North China around the 2020 Spring Festival(January to Februray 2020).Regional reductions in air pollutant emissions required to eliminate the PM2.5 heavy pollution episode are also *** results found that meteorological conditions for the Beijing-Tianjin-Hebei and surrounding"2+26"cities are the worst during the heavy pollution episode around the 2020 Spring Festival as compared with two other typical heavy pollution episodes that occurred after ***,because of the substantial reductions in air pollutant emissions in the"2+26"cities in recent years,and the32%extra reduction in emissions during January to February 2020 compared with the baseline emission levels of the autumn and winter of 2019 to 2020,the maximum PM2.5 level during this heavy pollution episode around the 2020 Spring Festival was much lower than that in the other two typical ***,these emission reductions are still not enough to eliminate regional heavy pollution *** with the actual emission levels during January to February 2020,a 20%extra reduction in air pollutant emissions in the"2+26"cities(or a 45%extra reduction compared with baseline emission levels of the autumn and winter of 2019 to 2020)could help to generally eliminate regionwide severe pollution episodes,and avoid heavy pollution episodes that last three or more consecutive days in Beijing;a 40%extra reduction in emissions(or a 60%extra reduction compared with baseline emission levels of the autumn and winter of 2019 to 2020)could help to generally eliminate regionwide and continuous heavy pollution *** analysis finds that during the clean period after the heavy pollution episode around the 2020 Spring Festival,the regionwide

关键词： "2+26"cities 2020 Spring Festival Heavy air pollution episode WRF-CMAQ model

Joint Retrieval of PM_(2.5) Concentration and Aerosol Optical Depth over China Using Multi-Task Learning on FY-4A AGRI

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Advances in Atmospheric Sciences 2025年第1期42卷 94-110页

作者： Bo LI Disong FU Ling YANG Xuehua FAN Dazhi YANG Hongrong SHI Xiang’ao XIA Electronic Engineering College Chengdu University of Information TechnologyChengdu 610225China Tianjin Meteorological Radar Research Trial Center Tianjin Meteorological BureauTianjin 300074China Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Research Centre on Meteorological Observation Engineering Technology China Meteorological AdministrationBeijing 100081China Key Laboratory of Atmospheric Environment and Extreme Meteorology Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001China University of Chinese academy of Sciences Beijing 100049China

Aerosol optical depth(AOD)and fine particulate matter with a diameter of less than or equal to 2.5μm(PM_(2.5))play crucial roles in air quality,human health,and climate ***,the complex correlation of AOD–PM_(2.5)and the limitations of existing algorithms pose a significant challenge in realizing the accurate joint retrieval of these two parameters at the same *** this point,a multi-task learning(MTL)model,which enables the joint retrieval of PM_(2.5)concentration and AOD,is proposed and applied on the top-of-the-atmosphere reflectance data gathered by the Fengyun-4A Advanced Geosynchronous Radiation Imager(FY-4A AGRI),and compared to that of two single-task learning models—namely,Random Forest(RF)and Deep Neural Network(DNN).Specifically,MTL achieves a coefficient of determination(R^(2))of 0.88 and a root-mean-square error(RMSE)of 0.10 in AOD *** comparison to RF,the R^(2)increases by 0.04,the RMSE decreases by 0.02,and the percentage of retrieval results falling within the expected error range(Within-EE)rises by 5.55%.The R^(2)and RMSE of PM_(2.5)retrieval by MTL are 0.84 and 13.76μg m~(-3)*** with RF,the R^(2)increases by 0.06,the RMSE decreases by 4.55μg m~(-3),and the Within-EE increases by 7.28%.Additionally,compared to DNN,MTL shows an increase of 0.01 in R^(2)and a decrease of 0.02 in RMSE in AOD retrieval,with a corresponding increase of 2.89%in *** PM_(2.5)retrieval,MTL exhibits an increase of 0.05 in R^(2),a decrease of 1.76μg m~(-3)in RMSE,and an increase of 6.83%in *** evaluation suggests that MTL is able to provide simultaneously improved AOD and PM_(2.5)retrievals,demonstrating a significant advantage in efficiently capturing the spatial distribution of PM_(2.5)concentration and AOD.

关键词： AOD PM_(2.5) FY-4A multi-task learning joint retrieval

Method of target tracking with Doppler blind zone constraint

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Journal of Systems Engineering and Electronics 2013年第6期24卷 889-898页

作者： Wei Han Ziyue Tang Zhenbo Zhu Department of air/Space based Early-warning Equipment Air Force Early Warning Academy

Doppler blind zone （DBZ） has a bad influence on the airborne early warning radar, although it has good detection performance for low altitude targets with pulse Doppler （PD） technology. In target tracking, the blind zone can cause target tracking breakage easily. In order to solve this problem, a parallel particle filter （PF） algorithm based on multi-hypothesis motion models （MHMMs） is proposed. The algorithm produces multiple possible target motion models according to the DBZ constraint. Particles are updated with the constraint in each motion model. Once the first measurement from the target which reappears from DBZ falls into the particle cloud formed by any model, the measurementtrack association succeeds and track breakage is avoided. The simulation results show that on the condition of different DBZ ranges, a high association ratio can be got for targets with different maneuverability levels, which accordingly improves the tracking quality.

关键词： Doppler blind zone (DBZ) track breakage particle filter (PF) multi-hypothesis motion model (MHMM) measurementtrack association

Comprehensive evaluation method of urban air quality statistics based on environmental monitoring data and its application

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Journal of Environmental Sciences 2023年第1期123卷 500-509页

作者： Linglu Qu Fahe Chai Shijie Liu Jingchun Duan Fan Meng Miaomiao Cheng Atmospheric Environment Institute Chinese Research Academy of Environmental SciencesBeijing 100012China Asia Center for air Pollution Research Niigata 950-2144Japan

air quality monitoring is effective for timely understanding of the current air quality status of a region or ***,the huge volume of environmental monitoring data,which has reasonable real-time performance,provides strong support for in-depth analysis of air pollution characteristics and ***,in the era of big data,to meet current demands for fine management of the atmospheric environment,it is important to explore the characteristics and causes of air pollution from multiple aspects for comprehensive and scientific evaluation of air *** study reviewed and summarized air quality evaluation methods on the basis of environmental monitoring data statistics during the 13th Five-Year Plan period,and evaluated the level of air pollution in the Beijing-Tianjin-Hebei region and its surrounding areas(i.e.,the“2+26”region)during the period of the three-year action plan to fight air *** suggest that air quality should be comprehensively,deeply,and scientifically evaluated from the aspects of air pollution characteristics,causes,and influences of meteorological conditions and anthropogenic *** is also suggested that a threeyear moving average be introduced as one of the evaluation indexes of long-term change of ***,both temporal and spatial differences should be considered when removing confounding meteorological factors.

关键词： air quality assessment air pollution Statistical analysis Environmental monitoring data Big data

A function-based behavioral modeling method for air combat simulation

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Journal of Systems Engineering and Electronics 2024年第4期35卷 945-954页

作者： WANG Tao ZHU Zhi ZHOU Xin JING Tian CHEN Wei College of Systems Engineering National University of Defense TechnologyChangsha 410073China Institute of Communication and Navigation Air Force Research AcademyBeijing 100085China

Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete ***, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.

关键词： air combat behavioral modeling intelligent agent

Influence of acetic acid on the morphology of indium oxide nanocrystals and the associated plasmonic properties

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Science China Materials 2025年第2期68卷 432-440页

作者： Jiangtong Su Peixian Li Zhe Liu Zifeng Liu Xiaoqi Hou Junli Duan Ning Dai Yang Li School of Physics and Optoelectronic Engineering Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China School of Chemistry and Material Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China University of Chinese academy of Sciences Beijing 100049China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China

Synthetic control of metal oxide nanocrystals with precise size and morphology is of great importance for promising optoelectronic applications due to their unique size-and shape-dependent optical/optoelectronic ***,the understanding of the mechanism for size and morphology control of metal oxide nanocrystals are less ***,we demonstrate that acetic acid,the byproduct of the initial chemical reaction of precursors,plays a dominant role in determining the morphology of indium oxide(In_(2)O_(3))nanocrystals by influencing the nucleation of the nanocrystals *** acetic acid would induce anisotropic growth,leading to the generation of nanoflowers,while limited existence of acetic acid results in sphere-shaped ***,the effects of geometries of In_(2)O_(3) nanocrystals on their plasmonic properties are *** resulting plasmonic In_(2)O_(3) nanocrystals show size-tunable plasmon resonance peaks in the near-infrared to mid-infrared regime and outstanding air/thermal *** work shall give an in-depth understanding of the mechanism for geometry control of nanocrystals and offer more opportunities in potential optoelectronic and photothermal applications based on plasmonic metal oxide nanocrystals.

关键词： colloidal semiconductor nanocrystals metal oxide nanocrystals localized surface plasmon resonance surface ligands geometry control

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A New Method for Sorting Unknown Radar Emitter Signal

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Chinese Journal of Electronics 2014年第3期23卷 499-502页

作者： CHEN Changxiao HE Minghao XU Jing HAN Jun air Force Early Warning academy

Sorting rate of common method is not high and it is sensitive to the Signal noise ratio(SNR), in order to solve these problems, bispectrum two dimensions characteristics complexity is applied to sort unknown complicated radar signal and a high sorting rate would be got. The bispectrum of received signal is extracted and it is predigested to two dimensions characteristic, the box dimension and information dimension are extracted from the two dimensions characteristic and used as the sorting characteristics, and the last sorting is accomplished by using KFCM algorithm. For the bispectrum of different signal is distinguishing and it is not sensitive to SNR, the box dimension and information dimension are divisible and steady, the advantage of this new method is validated by simulation results, and the lowest sorting rate is 90% at SNR equals to 10 dB.

关键词： Sorting Bispectrum Box dimension Information dimension SNR

Emission characteristics of biogenic volatile organic compounds in a subtropical pristine forest of southern China

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Journal of Environmental Sciences 2025年第2期148卷 665-682页

作者： Xi Chen Daocheng Gong Youjing Lin Qiao Xu Yujin Wang Shiwei Liu Qinqin Li Fangyuan Ma Jiangyong Li Shuo Deng Hao Wang Boguang Wang Institute for Environmental and Climate Research Jinan UniversityGuangzhou 511443China Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests China Australia-China Centre for air Quality Science and Management(Guangdong) Guangzhou 511443China Hainan Provincial Ecological and Environmental Monitoring Center Haikou 571126China

Emission characteristics of biogenic volatile organic compounds(BVOCs)from dominant tree species in the subtropical pristine forests of China are extremely *** we conducted in situ field measurements of BVOCs emissions from representative mature evergreen trees by using dynamic branch enclosures at four altitude gradients(600-1690ma.s.l.)in the Nanling Mountains of southern *** characteristics as well as seasonal and altitudinal variations were *** emission rates and canopyscale emission factors were then *** showed that BVOCs emission intensities in the wet season were generally higher than those in the dry *** were the dominant BVOCs emitted from most broad-leaved trees,accounting for over 70%of the *** superba,Yushania basihirsuta and Altingia chinensis had relatively high emission intensities and secondary pollutant formation *** localized emission factors of isoprene were comparable to the defaults in the Model of Emissions of Gases and Aerosols fromNature(MEGAN),while emission factors of monoterpenes and sesquiterpenes were 2 to 58 times of those in the *** results can be used to update the current BVOCs emission inventory in MEGAN,thereby reducing the uncertainties of BVOCs emission estimations in forested regions of southern China.

关键词： Biogenic volatile organic compounds(BVOCs) Dynamic enclosure system Nanling Mountains Emission factors Emission rates Chemical reactivity

Fast ISAR imaging method based on scene segmentation

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Journal of Systems Engineering and Electronics 2017年第6期28卷 1078-1088页

作者： Mingjiu Lü Shaodong Li Wenfeng Chen Jun Yang Xiaoyan Ma air Force Early Warning academy Wuhan 430019 China

Although compressed sensing inverse synthetic aperture radar(ISAR) imaging methods are widely used in radar signal processing, its reconstructing time and memory storage space requirements are very high. The main reason is that large scene reconstruction needs a higher dimension of the sensing matrix. To reduce this limitation, a fast high resolution ISAR imaging method,which is based on scene segmentation for random chirp frequencystepped signals, is proposed. The idea of scene segmentation is used to solve the problems aforementioned. In the method,firstly, the observed scene is divided into multiple sub-scenes and then the sub-scenes are reconstructed respectively. Secondly, the whole image scene can be obtained through the stitching of the sub-scenes. Due to the reduction of the dimension of the sensing matrix, the requirement of the memory storage space is reduced substantially. In addition, due to the nonlinear superposition of the reconstructed time of the segmented sub-scenes, the reconstruction time is reduced, and the purpose of fast imaging is ***, the feasibility and the related factors which affect the performance of the proposed method are also analyzed, and the selection criterion of the scene segmentation is afforded. Finally,theoretical analysis and simulation results demonstrate the feasibility and effectiveness of the proposed method.

关键词： compressed sensing(CS) inverse synthetic aperture radar(ISAR) imaging random chirp frequency-stepped signal scene segmentation