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Characteristics of Spatial and Temporal Vegetation Index Variability and Its Responses to Temperature and Precipitation in Mongolia

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Journal of Resources and Ecology 2024年第5期15卷 1175-1184页

作者： YANG Meihuan LI Yawen WANG Tao WANG Juanle LI Pengfei LI Ting HUANG Jing Ochir ALTANSUKH Davaadorj DAVAASUREN School of Geomatics and Geoinformation Xi’an University of Science and TechnologyXi’an 710054China Institute of Land and Space Xi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChineseAcademy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Department of Environment and Forest Engineering School of Engineering and Technology and Environmental Engineering LaboratoryNationalUniversity of MongoliaUlaanbaatar 14201Mongolia Department of Geography School of Art and SciencesNational University of MongoliaUlaanbaatar 14201Mongolia

The Mongolian Plateau,a vital ecological barrier in northern China,is of great importance for studying vegetation dynamics in Mongolia against the background of climate *** studies can enhance our understanding of regional vegetation responses to global warming and contribute to the establishment of a stronger ecological barrier in northern ***,we analyzed the spatial and temporal characteristics of the NDVI(normalized difference vegetation index)in Mongolia using 8 km resolution GIMMS NDVI3g data from 1990 to 2022,along with temperature,precipitation,and elevation *** analysis and correlation methods were used to examine the relationships between the NDVI and temperature,as well as *** results showed four important aspects of these relationships.(1)The NDVI in Mongolia increased significantly from 1990 to 2022 at a rate of 0.0015 yr^(-1)(P<0.05).(2)Mongolia’s NDVI increased from 1990 to 2022 in 60.73%of the *** this total,the area with a significant increase accounted for 31.67%and was concentrated on the eastern and western *** area experiencing a significant decrease accounted for 15.67%and was mainly located on the southwestern edges.(3)The NDVI analysis revealed significant increasing trends in all regions except for those at elevations of 1500-2000 *** greatest rate of increase was observed between 500 and 1000 m,and the increasing trend weakened as elevation continued to increase before gradually becoming significant ***,the NDVI increased significantly across different slopes,and the rate of increase decreased as the slope increased.(4)From 1990 to 2022,Mongolia’s NDVI was mostly negatively correlated with *** occurred over 66.75%of the total land area,with 17.21%of the region exhibiting a significant negative correlation,mainly in the ***,the NDVI demonstrated a positive correlation with precipitation,encompassing 86.71%of the total land *** 4

关键词： normalized difference vegetation index slope elevation trend analysis correlation analysis Mongolia

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Key Technique of Constructing Collaborating Environment Based on OPENMBEE

Key Technique of Constructing Collaborating Environment Base...

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International Conference on Computer and Communications (ICCC)

作者： Junjie Xue Junhua Zhou Guoqiang Shi Yanhong Jiang Shuying Xu Hongyan Quan State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Engineering Beijing China Science and Technology on Space System Simulation Laboratory Beijing Simulation Center Beijing China School of Software Engineering East China Normal University Shanghai China School of Computer Science and Technology East China Normal University Shanghai China

ISBN: (数字)9781728186351

ISBN: (纸本)9781728186368

With the development of integrated design and manufacturing technology, it is necessary to consider how to integrate a variety of modeling tools in the procedure of complex product design driven by the model-centric conception. In this work, we explored the development technology of multi-tool integration based on the Open Model Based Engineering Environment (OpenMBEE). We provide a multi-tool integration system solution, in which the integration schemes under different environments of LAN and virtual machine are designed, and the system scheme of multi-tool integration is also studied. From the idea of model design conception, we integrate the requirement analysis tools Cameo. On the basis, Model Management system (MMS) and View Editor(VE), as well as the specific model analysis tool MATLAB and 3D visual simulation tool Creo are also integrated seamlessly. The effectiveness of the proposed integration strategies is verified by some practical instances. That is verified that our study can provide an effective design idea for complex production.

关键词： Analytical models Solid modeling Computational modeling Tools Product design Mathematical model Matlab

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Effect of potential HONO sources on peroxyacetyl nitrate(PAN)formation in eastern China in winter

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Journal of Environmental sciences 2020年第8期32卷 81-87页

作者： Jingwei Zhang Yitian Guo Yu Qu Yong Chen Ruipeng Yu Chaoyang Xue Rui Yang Qiang Zhang Xingang Liu Yujing Mu Jing Wang Can Ye Haihan Zhao Qiangqiang Sun Ziwen Wang Junling An State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric Physics(IAP)Chinese Academy of SciencesBeijing 100029China College of Earth Science University of Chinese Academy of SciencesBeijing 100049China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Guangzhou Meteorological Observatory Guangzhou 511430China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijingChina Collaborative Innovation Center for Regional Environmental Quality BeijingChina State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China College of Land Science and Technology China Agricultural UniversityBeijing 100193China Qinghai Climate Center Qinghai Meteorological BureauXiningQinghai 810001China

As an important secondary photochemical pollutant,peroxyacetyl nitrate(PAN)has been studied over decades,yet its simulations usually underestimate the corresponding observations,especially in polluted *** observations in north China found unusually high concentrations of PAN during wintertime heavy haze events,but the current model still cannot reproduce the observations,and researchers speculated that nitrous acid(HONO)played a key role in PAN *** the first time we systematically assessed the impact of potential HONO sources on PAN formation mechanisms in eastern China using the Weather Research and Forecasting/Chemistry(WRF-Chem)model in February of *** results showed that the potential HONO sources significantly improved the PAN simulations,remarkably accelerated the RO x(sum of hydroxyl,hydroperoxyl,and organic peroxy radicals)cycles,and resulted in 80%–150%enhancements of PAN near the ground in the coastal areas of eastern China and 10%–50%enhancements in the areas around 35–40°N within 3 km during a heavy haze *** direct precursors of PAN were aldehyde and methylglyoxal,and the primary precursors of PAN were alkenes with C>3,xylenes,propene and *** above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting PAN studies.

关键词： Nitrous acid(HONO) Peroxyacetyl nitrate(PAN) WRF-Chem model Winter haze RO x cycles

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Progress of the TianQin project

arXiv

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arXiv 2025年

作者： Luo, Jun Bai, Shaojun Bai, Yan-Zheng Cai, Lin Dang, Hao Dong, Qijia Duan, Hui-Zong Du, Yuanbo Fan, Lei Fu, Xinju Gao, Yong Gou, Xingyu Gu, Defeng Guo, Changlei Hong, Wei Hu, Bin Hu, Heran Hu, Ming Hu, Yi-Ming Huang, Fa Peng Ji, Xin Jiang, Yuan-Ze Li, En-Kun Li, Hongyin Li, Ming Li, Ming Li, Yong Li, Zhu Li, Zizheng Lian, JunXiang Liang, Yu-Rong Lin, Xudong Liu, Jianping Liu, Lin-Xia Liu, Kui Liu, Li Liu, Minghe Liu, Qi Liu, Yan-Chong Liu, Yue Luo, Peng-Shun Luo, Yingxin Ma, Yi-Qiu Ma, Yun Meng, Yunhe Milyukov, Vadim Peng, Jian-Guo Postnov, Konstantin Qu, Shao-Bo Shan, Tilei Shao, Cheng-Gang Shi, Changfu Song, Pei-Yi Song, Yunfei Su, Wei Tan, Ding Yin Tan, Shuping Tan, Yu-Jie Tan, Wenhai Tu, Liangcheng Wang, Cheng-Rui Wang, Guoyong Wang, Lijiao Wang, Pan-Pan Wang, Shun Wang, Xiaoyong Wang, Xudong Wang, Yan Wei, Ran Wu, Shu-Chao Xu, Jie Xu, Zhi-Lin Xue, Chao Yan, Hao Yan, Yong Yang, Changpeng Yang, Shanqing Yeh, Hsien-Chi Yin, Hang Tong, Yelong Yu, Jian-Bo Yuan, Wen-Hao Zhang, Bu-Tian Zhang, Dexuan Zhang, Jian-Dong Zhang, Jie Zhang, Lihua Zhang, Xuefeng Zhao, Guoying Zhao, Liqian Zhao, Xin Zhou, An-Nan Zhou, Hao Zhou, Peng Zhou, Yupeng Zhou, Ze-Bing Zhu, Fan Zhu, Liang-Gui Zhu, Lin Zou, Kui Mei, Jianwei MOE Key Laboratory of TianQin Mission TianQin Research Center for Gravitational Physics School of Physics and Astronomy Frontiers Science Center for TianQin Gravitational Wave Research Center of CNSA Sun Yat-sen University Zhuhai Campus Zhuhai519082 China National Gravitation Laboratory MOE Key Laboratory of Fundamental Physical Quantities Measurement School of Physics Huazhong University of Science and Technology Wuhan430074 China DFH Satellite Co. Ltd. Beijing100094 China Beijing Institute of Space Mechanics & Electricity Beijing100076 China National Key Laboratory of Spacecraft Thermal Control of Institute of Spacecraft System Engineering Beijing100094 China Space Star Technology CO. LTD. Beijing100095 China Beijing Institute of Control Engineering Beijing100094 China School of Artificial Intelligence Sun Yat-sen University Zhuhai Campus Zhuhai519082 China Shanxi Xi’an710199 China Sternberg Astronomical Institute M.V. Lomonosov Moscow State University Moscow119234 Russia Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China

TianQin is a future space-based gravitational wave observatory targeting the frequency window of 10−4 Hz ∼ 1 Hz. A large variety of gravitational wave sources are expected in this frequency band, including the merger of massive black hole binaries, the inspiral of extreme/intermediate mass ratio systems, stellar-mass black hole binaries, Galactic compact binaries, and so on. TianQin will consist of three Earth orbiting satellites on nearly identical orbits with orbital radii of about 105 km. The satellites will form a normal triangle constellation whose plane is nearly perpendicular to the ecliptic plane. The TianQin project has been progressing smoothly following the "0123" technology roadmap. In step "0", the TianQin laser ranging station has been constructed and it has successfully ranged to all the five retro-reflectors on the Moon. In step "1", the drag-free control technology has been tested and demonstrated using the TianQin-1 satellite. In step "2", the inter-satellite laser interferometry technology will be tested using the pair of TianQin-2 satellites. The TianQin-2 mission has been officially approved and the satellites will be launched around 2026. In step "3", i.e., the TianQin-3 mission, three identical satellites will be launched around 2035 to form the space-based gravitational wave detector, TianQin, and to start gravitational wave detection in space. © 2025, CC BY.

关键词： Laser interferometry

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Range migration-based Doppler ambiguous integer estimation for moving targets with azimuth spectrum aliasing 6

Range migration-based Doppler ambiguous integer estimation f...

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6th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2019

作者： Zhang, Ying Xiong, Wei Dong, Xichao Hu, Cheng Liu, Chengxiang Sun, Yang Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China School of Information and Electronics Beijing Institute of Technology Beijing China

ISBN: (纸本)9781728129129

In some case, the azimuth spectrum bandwidth is larger than the pulse repetition frequency (PRF), leading to a whole azimuth spectrum has been folded into multiple subsegments and aliased. Therefore, the traditional Doppler ambiguous integer estimation method cannot be used directly. In this paper, the influence of Doppler ambiguous integer on residual range migrations' slope is analyzed. Based on the slope, the Doppler ambiguous integer estimation method for moving targets with azimuth spectrum aliasing is given. From the simulation results, the Doppler ambiguous integer can be estimated accurately by proposed method. © 2019 IEEE.

关键词： Synthetic aperture radar

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STAR-RIS Enabled ISAC systems: Joint Rate Splitting and Beamforming Optimization

arXiv

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arXiv 2024年

作者： Liu, Yuan Zhang, Ruichen Jiang, Ruihong Zhu, Yongdong Hu, Huimin Ni, Qiang Fei, Zesong Niyato, Dusit The Research Center for Space Computing System Zhejiang Laboratory Hangzhou311100 China The College of Computing and Data Science Nanyang Technological University 639798 Singapore The State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China The School of Communications and Information Engineering The School of Artificial Intelligence Xi’an University of Posts and Telecommunications Xi’an710121 China The School of Computing and Communications Lancaster University LancasterLA1 4WA United Kingdom The School of Information and Electronics Beijing Institute of Technology Beijing100081 China

This paper delves into an integrated sensing and communication (ISAC) system bolstered by a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS). Within this system, a base station (BS) is equipped with communication and radar capabilities, enabling it to communicate with ground terminals (GTs) and concurrently probe for echo signals from a target of interest. Moreover, to manage interference and improve communication quality, the rate splitting multiple access (RSMA) scheme is incorporated into the system. The signal-to-interference-plus-noise ratio (SINR) of the received sensing echo signals is a measure of sensing performance. We formulate a joint optimization problem of common rates, transmit beamforming at the BS, and passive beamforming vectors of the STAR-RIS. The objective is to maximize sensing SINR while guaranteeing the communication rate requirements for each GT. We present an iterative algorithm to address the non-convex problem by invoking Dinkelbach’s transform, semidefinite relaxation (SDR), majorization-minimization, and sequential rank-one constraint relaxation (SROCR) theories. simulation results manifest that the performance of the studied ISAC network enhanced by the STAR-RIS and RSMA surpasses other benchmarks considerably. The results evidently indicate the superior performance improvement of the ISAC system with the proposed RSMA-based transmission strategy design and the dynamic optimization of both transmission and reflection beamforming at STAR-RIS. © 2024, CC BY.

关键词： Signal to noise ratio

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Research on Internet of Things Vulnerability Based on Complex Network Attack Model 3rd

Research on Internet of Things Vulnerability Based on Comple...

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3rd International Conference on space Information Networks, SINC 2018

作者： Liu, Chengxiang Xiong, Wei Company of Postgraduate Management Space Engineering University Beijing China Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China

ISBN: (纸本)9789811359361

The Internet of Things brings convenience to people’s lives and it is also vulnerable to external attacks due to its own vulnerability. For this reason, analyzing the vulnerability of the Internet of Things is very necessary and meaningful. The paper starts with the characteristics of the Internet of Things and firstly constructs its network attack model. And then we simulate the attack on the model according to the attack rules. Furthermore, an experimental analysis of the nodes vulnerability is conducted by the theory of complex networks, and indicators of network characteristics are quantified based on the removal of vulnerable nodes. The experimental results show that the vulnerability of the system will show different patterns of attenuation as the proportion of node deletion increases. © 2019, Springer Nature Singapore Pte Ltd.

关键词： Complex networks

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Neural architecture search for fault diagnosis

arXiv

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arXiv 2020年

作者： Li, Xudong Hu, Yang Zheng, Jianhua Li, Mingtao National Space Science Center. CAS University of Chinese Academy of Sciences Beijing China Science and Technology on Complex Aviation System Simulation Laboratory 9236 mailbox Beijing China

Data-driven methods has made great progress in fault diagnosis, especially deep learning method. Deep learning is suitable for processing big data, and has a strong feature extraction ability to realize end-to-end fault diagnosis systems. Due to the complexity and variability of experimental data, some deep learning models are designed to be complex. However, designing neural network architecture requires rich professional knowledge and debugging experience, and a lot of experiments are needed to screen models and hyperparameters, increasing the difficulty of developing deep learning models. Fortunately, neural architecture search (NAS) is developing rapidly, and is becoming one of the next directions for deep learning. Given a search space, NAS can automatically search for the optimal network architecture. In this paper, we proposed a NAS method for fault diagnosis using reinforcement learning. A recurrent neural network is used as an agent to generate the network architecture. The accuracy of the generated network on the validation dataset is fed back to the agent as a reward, and the parameters of the agent are updated through the strategy gradient algorithm. In order to speed up the search process, parameters sharing method is adopted in this paper. We use PHM 2009 Data Challeng gearbox dataset to prove the effectiveness of propsed method, and obtain state-of-the-art results compared with other artificial designed network structures. To authors best knowledge, its the first time that NAS has been applied in fault diagnosis. Copyright © 2020, The Authors. All rights reserved.

关键词： Failure analysis

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Fast Charge Separation and Transfer Strategy in Polymeric Carbon Nitride for Efficient Photocatalytic H2 Evolution: Coupling Surface Schottky Junctions and Interlayer Charge Transfer Channels

SSRN

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SSRN 2022年

作者： Gao, Manyi Tian, Fenyang Zhang, Xin Chen, Zhaoyu Yu, Yongsheng Yang, Weiwei Hou, Yanglong MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical Engineering Harbin Institute of Technology Heilongjiang Harbin150001 China Space Environment Simulation Research Infrastructure Harbin Institute of Technology Heilongjiang Harbin150001 China School of Materials Science and Engineering Peking University Beijing100871 China

Reinforcing the charge separation and transfer in layered polymeric carbon nitride (PCN) is the key issue to enhance its photocatalytic activity but still remains very challenging. Herein, for the first time, the synergetic Pd single atoms (PdSAs) and carbon-supported Pd nanoparticles (NPs) are introduced into the interlayer and surface of layered PCN respectively to address this challenge. The PdSAs are in intimate contact with the adjacent PCN layers and serve as interlayer charge transfer channels, while the carbon-supported Pd NPs contribute to multistep PCN-carbon-Pd NPs Schottky junctions on PCN surface. Experiments and theoretical calculations demonstrate that such unique architectures provide intrinsic driving force to extract the electrons from PCN to outermost Pd NPs with high migration rate via vertical PdSAs channels. This directional charge transfer in PCN greatly expedite the separation of charge carriers in both inner and surface of PCN and simultaneously yield electron-rich Pd NPs active sites with optimized H2 adsorption energy, thus leading to improved intrinsic H2 evolution reaction kinetics. Consequently, the Pd/PCN2 performs ultrahigh photocatalytic H2 evolution rate of 83.34 mmol g-1 h-1 in the dispersed particulate system and 100.4 mmol h-1 m-2 in the film form under simulated sunlight. This work provides a new promising approach to engineer the spatial charge transfer behaviors for high-performance PCN-based photocatalysts. © 2022, The Authors. All rights reserved.

关键词： Hydrogen production

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Continuous and comprehensive atmospheric observations in beijing:a station to understand the complex urban atmospheric environment

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Big Earth Data 2020年第3期4卷 295-321页

作者： Yongchun Liu Chao Yan Zemin Feng Feixue Zheng Xiaolong Fan Yusheng Zhang Chang Li Ying Zhou Zhuohui Lin Yishou Guo Ying Zhang Li Ma Wenshuo Zhou Zhikun Liu Lubna Dada Kaspar Dallenbach Jenni Kontkanen Runlong Cai Tommy Chan Biwu Chu Wei Du Lei Yao Yonghong Wang Jing Cai Juha Kangasluoma Tom Kokkonen Joni Kujansuu Anton Rusanen Chenjuan Deng Yueyun Fu Rujing Yin Xiaoxiao Li Yiqun Lu Yiliang Liu Chaofan Lian Dongsen Yang Weigang Wang Maofa Ge Yuesi Wang Douglas R.Worsnop Heikki Junninen Hong He Veli-Matti Kerminen Jun Zheng Lin Wang Jingkun Jiang Tuukka Petaja Federico Bianchi Markku Kulmala Aerosol and Haze Laboratory Beijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijingChina Institute for Atmospheric and Earth System Research/Physics Faculty of ScienceUniversity of HelsinkiHelsinkiFinland State Key Joint Laboratory of Environment Simulation and Pollution Control State Environmental Protection Key Laboratory of Sources and Control of Air Pollution ComplexSchool of EnvironmentTsinghua UniversityBeijingChina State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijingChina Department of Environmental Science&Engineering Fudan UniversityShanghaiChina State Key Laboratory for Structural Chemistry of Unstable and Stable Species Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijingChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing University of Information Science&TechnologyNanjingChina State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Aerodyne Research Inc. BillericaMassachusettsUSA Institute of Physics University of TartuTartuEstonia Joint International Research Laboratory of Atmospheric and Earth System Sciences School of Atmospheric SciencesNanjing UniversityNanjingChina

Due to profound impact on climate and human health,air quality has attracted attention from all levels of the civil *** key step in the provision of required tools for the society to tackle the complex air quality problem is to characterize it in a comprehensive manner with a long-term ***,we describe a continuous and comprehensive observation station and its accompanying state-ofthe-art instrumentation that was established to investigate the complex urban atmospheric environment in a rapidly developing Chinese *** station,located in downtown beijing,aims to study air quality by identifying the major atmospheric pollutants and key processes determining their formation and loss mechanisms.A few hundreds of parameters are continuously measured with the state-of-the-art instruments,including trace gas concentrations,aerosol particle size distributions,and mass concentrations,covering aerosol particle chemical composition from molecules to micrometer-sized aerosol *** produced long-term,comprehensive big data with around 1�10^(11)bytes per *** this paper,we provide an overview on the facilities of the station,the instrumentation used,the workflow of continuous observations and examples of results from 2018 to 2019 and a basis for establishing a modern long-term,comprehensive atmospheric urban observation station in other megacities.

关键词： Continuous and comprehensive atmospheric observation air pollution complex photochemical smog haze new particle formation

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