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2nd International Conference on Computer engineering and Application, ICCEA 2021

作者： Dong, Zeyu Lv, Fengrong Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

Signal bispectral transformation can not only suppress the influence of Gaussian white noise on signal modulation recognition, but also retain the signal amplitude and phase information. It is also used to extract the non-linear characteristics. Compared with other high-order spectra, bispectrum has a simple processing flow. However, the direct use of all bispectrum as signal features will lead to two-dimensional template matching, causing lots of calculations. Converting two-dimensional bispectrum into one-dimensional sequence, for example, extracting slice information of bispectrum, or using integral bispectrum apparently reduce the amount of data to be processed while retaining part of the bispectrum information. We input the extracted bispectral transformation of radar signals into the neural network to realize modulation recognition. The simulations validate our conclusions that our proposed methods still have a high recognition probability while SNR is low. © 2021 IEEE.

关键词： Template matching

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Semi-supervised Open-set Recognition of Radar Active Jamming

Semi-supervised Open-set Recognition of Radar Active Jamming

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2021 CIE International Conference on Radar, Radar 2021

作者： Li, Hao Fang, Xueli Zhang, Lei Kang, Hui Zhang, Wei School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665498142

With the emergence of various kinds of complex radar jamming, radar jamming intelligent recognition technology has increasingly become the key to electronic counter-counter measures. To achieve radar jamming open-set recognition with a small number of tagged samples, Generative adversarial network-based pseudolabeled convolutional neural network (GAN-PL-CNN) model is proposed in this paper. Firstly, radar jamming is modelled, and the radar jamming datasets with known and unknown types are established after time-frequency transformation and image processing. Then, the adaptive pseudolabeling method is used to achieve semi-supervised recognition of radar jamming by combining the learning capability of convolutional neural networks and the characteristics of pseudolabeling to increase labeled samples intelligently. Finally, generative adversarial networks are introduced to enhance the recognition ability of the model and the discrimination ability of the unknown type through the game between the generator and the discriminator in the iterative process. Experimental results show that the GAN-PL-CNN model achieves 89.7%-95.1% for known types and 30.7%-86.8% for unknown types at 3%-6% labeling rate. As the number of labeled samples increases, the recognition effect becomes better and has a greater ability to exclude unknown type. © 2021 IEEE.

关键词： convolutional neural network open-set recognition pseudo-label Radar active jamming

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Radar Signal Detection Based on Ambiguity Function and Deep Learning 2

Radar Signal Detection Based on Ambiguity Function and Deep ...

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2nd International Conference on Computer engineering and Application, ICCEA 2021

作者： Lv, Fengrong Dong, Zeyu Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

The ambiguity function describes the joint characteristics of the signal in the time domain and the frequency domain, and is usually used for signal recognition. The time domain and frequency domain distribution of noise is more spurious than the signal. Its ambiguity function can also reflect its characteristics. However, the direct use of the ambiguity function as the signal feature will increase the amount of calculation of the detection system, so slice it, which reduces the burden on the system for detecting signal information while preserving the information. At the same time, the radar signal detection based on neural network can avoid the influence of artificially setting the threshold on the detection performance of the system. So, we propose an algorithm for inputting the extracted fuzzy function slice sequence into a neural network to realize signal detection. simulation proves that when the signal-To-noise ratio of the received signal is very low, our proposed method still has a high detection probability. © 2021 IEEE.

关键词： Signal detection

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The Earth Summit Mission-2022:Successful ozone soundings contribute to source identification in the north *** region

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Journal of Environmental Sciences 2024年第2期136卷 412-421页

作者： Jinqiang Zhang Chunxiang Ye Yuejian Xuan Zhixuan Bai Weili Lin Dan Li Lingkun Ran Baofeng Jiao YaomingMa Weiqiang Ma Nan Yao Yunshu Zeng Daren Lv Tong Zhu Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Environmental Sciences and Engineering Center for Environment and HealthPeking UniversityBeijing 100871China Key Laboratory of Ecology and Environment in Minority Areas(Minzu University of China) National Ethnic Affairs CommissionBeijing 100081China Key Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Land-Atmosphere Interaction and Its Climatic Effects Group State Key Laboratory of Tibetan Plateau Earth SystemResources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China College of Atmospheric Science Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan Electronic Engineering College Chengdu University of Information TechnologyChengdu 610225China

As part of“The Earth Summit Mission-2022”during the second Tibetan Plateau Scientific Expedition and Research(STEP)in April and May 2022,we conducted the ozone sounding experiment(an ozonesonde mated to a radiosonde)at *** Base Camp(MQBC;86.85°E,28.14°N;5200 m),a location at an extremely high altitude.A total of ten sounding profiles were obtained between April 30 and May 06,2022,of which seven profiles were above35 km in altitude,with a maximum detection altitude up to 39.0 *** study presents the temporal variation and vertical distributions of atmospheric temperature,humidity,and ozone during the MQBC *** averaged ozone concentration was high(68.3 ppbv)at the surface and then increased smoothly until peaking(~110 ppbv)in the middle troposphere(approximately 10 km),and afterward,the ozone concentration increased rapidly from the upper troposphere to a maximum of~10 ppmv at~30 *** enhanced ozone concentration in the middle troposphere was associated with the blocking high pressure,and transport from the southern flank of the Himalayas occurred during the campaign *** average total ozone column was 291.9±21.4 DU for the seven profiles exceeding 35km in *** ozonesonde measurements were also compared with the vertical ozone profiles retrieved from the space-borne ozone products from the Microwave Limb Sounder(MLS)onboard the Aura satellite and the Atmospheric Infrared Sounder(AIRS)onboard the Aqua satellite.

关键词： Ozone soundings Mt.Qomolangma Vertical ozone structure Ozone source Satellite data

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Shifting agricultural land use and its unintended water consumption in the North China Plain

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Science Bulletin 2024年第24期69卷 3968-3977页

作者： Liang Dong Di Long Caijin Zhang Yingjie Cui Yanhong Cui Yiming Wang Luoqi Li Zhongkun Hong Ling Yao Jinling Quan Liangliang Bai Hao Wang Bridget R.Scanlon Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Hydrosphere Sciences of the Ministry of Water Resources Beijing 100084China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Science and Technology Advisory Center Haihe River Water Resources CommissionMinistry of Water ResourcesTianjin 300170China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Bureau of Economic Geology Jackson School of GeosciencesUniversity of Texas at AustinAustin TX78712USA

Agricultural land use(ALU)critically influences food production and water resource *** study examines the dynamics of ALU in the North China Plain(NCP),a region characterized by intensive agri-culture and severe groundwater over-exploitation,focusing on the multidimensional drivers and their implications for water resource *** employing an elaborate classification scheme based on satellite imagery and extensive first-hand field data,we identified significant shifts in crop *** 2013 to 2017,there was a notable transition from double crops(primarily wheat-maize)to single crops(primarily maize),covering 4600 km^(2)and accounting for 42%of single crops in *** 2017 to 2022,there was a shift from single crops to economic forests,encompassing 3600 km^(2)and 22%of eco-nomic forests in 2017,including orchards,timber trees,and shelter forest *** shifts resulted in an 11%decrease in grain acreage(6800 km^(2))but an 11%increase in crop water consumption(6.3 km^(3))during ***,water consumption by economic forests increased by 126%(9.4 km^(3))during this *** study highlights the critical need to balance competing demands for food and water security,providing valuable insights applicable to other agriculturally intensive regions worldwide.

关键词： Agricultural land use Remote sensing imagery Random forest classification Shifts in crop patterns Water consumption

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Fast imaging algorithm for the ImpGPR based on windowed valid aperture estimation 8

Fast imaging algorithm for the ImpGPR based on windowed vali...

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8th International Conference on Intelligent Computing and Signal Processing, ICSP 2023

作者： Zhang, Mengyuan Zhou, Peng Lei, Yang Peng, Zhike Shanghai Jiao Tong University State Key Laboratory of Mechanical System and Vibration Shanghai China Infrastructure Inspection Research Institute China Academy of Railway Sciences Beijing China Ningxia University School of Mechanical Engineering Yinchuan China

ISBN: (纸本)9798350302455

Imaging using impulse ground penetrating radar (ImpGPR) is an effective technique for detecting and locating hidden targets. The classical back-projection (BP) algorithm is widely used to achieve the imaging of GPR data. However, its effectiveness can be limited when dealing with a large amount of multi-channel data due to the considerable computational load required. To address this challenging issue, this paper proposes a novel fast windowed imaging algorithm. The proposed algorithm is applied to image a simulated multi-target case and a concrete-cavity wall. Compared with the BP algorithm, the proposed algorithm is able to achieve higher computational efficiency while maintaining similar image quality. © 2023 IEEE.

关键词： Ground penetrating radar systems

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Design and dynamic analysis of integrated architecture for vibration energy harvesting including piezoelectric frame and mechanical amplifier

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Applied Mathematics and Mechanics(English Edition) 2021年第6期42卷 755-770页

作者： Xiangjian DUAN Dongxing CAO Xiaoguang LP Yongjun SHEN Beijing Institute of Structure and Environment Engineering Beijing 100076China Faculty of Materials and Manufacturing Bejing University of TechnologyBeijing 100124China Beijing Key Laboratory of Nonlinear V ibrations and Strength of Mechanical Structures Beijing 100124China State Key Laboratory of Mechanical Behavior and System Safety of Trafic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Vibration energy harvesters(VEHs) can transform ambient vibration energy to electricity and have been widely investigated as promising self-powered devices for wireless sensor networks, wearable sensors, and applications of a micro-electro-mechanical system(MEMS). However, the ambient vibration is always too weak to hinder the high energy conversion efficiency. In this paper, the integrated frame composed of piezoelectric beams and mechanical amplifiers is proposed to improve the energy conversion efficiency of a VEH. First, the initial structures of a piezoelectric frame(PF) and an amplification frame(AF) are designed. The dynamic model is then established to analyze the influence of key structural parameters on the mechanical amplification factor. Finite element simulation is conducted to study the energy harvesting performance, where the stiffness characteristics and power output in the cases of series and parallel load resistance are discussed in detail. Furthermore, piezoelectric beams with variable cross-sections are introduced to optimize and improve the energy harvesting efficiency. Advantages of the PF with the AF are illustrated by comparison with conventional piezoelectric cantilever beams. The results show that the proposed integrated VEH has a good mechanical amplification capability and is more suitable for low-frequency vibration conditions.

关键词： vibration energy harvesting mechanical amplifier piezoelectric frame(PF) amplification frame(AF) variable cross-section beam

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In situ induced cation-vacancies in metal sulfides as dynamic electrocatalyst accelerating polysulfides conversion for Li-S battery

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Journal of Energy Chemistry 2022年第12期75卷 74-82,I0003页

作者： Rongrong Li Hao Sun Caiyun Chang Yuan Yao Xiong Pu Wenjie Mai Siyuan Laboratory Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy MaterialsDepartment of PhysicsJinan UniversityGuangzhou 510632GuangdongChina CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Cation vacancy engineering is considered to be one of the effective methods to solve the issues of shuttling and sluggish redox kinetics of Li PSs owing to the intrinsic tunability of electronic ***,cation vacancies are few studied in the Li-S realm due to their complex and rigid preparation *** this work,one-step pyrolysis is reported to in situ introduce Fe-vacancies into iron sulfide(Fe_(0.96)S)as a sulfur *** this host structure,Fe_(0.96)S is first employed as an adsorbent and catalyst in Li-S *** the carbonization process,a tight contact structure of Fe_(0.96)S crystal and carbon network(Fe_(0.96)S@C)is in situ constructed,and the carbon layer as a conductor provides smooth electrons transfer pathways for redox ***,due to the introduction of Fe-vacancies in Fe S crystal,the adsorption capability and catalytic effect for Li PSs have been substantially ***,the presence of Fe_(0.96)S crystal favors the mobility of electron and diffusion of Li+,which is revealed by the experiments and theoretical *** synergy respective advantages effect of Fe_(0.96)S and carbon,the Fe_(0.96)S@C-S cathode delivers high-rate capability at 5.0 C and stable long-life *** under a high sulfur loading of 3.5 mg/cm^(2),the durable cyclic stability is still exhibited with the capacity retention of 93%over 400 cycles at 1.0 C,and the coulombic efficiency is≥98%.Noting that this strategy greatly simplifies the synthetic process of currently known cation-vacancy materials and furnishes a universal mentality for designing both divinable and astonishing new cation-vacancy materials.

关键词： Cation vacancy Fe_(0.96)S@C structure Catalytic conversion Lithium-sulfur battery

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The impact of the atmospheric turbulence-development tendency on new particle formation: a common finding on three continents

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National Science Review 2021年第3期8卷 140-150页

作者： Hao Wu Zhanqing Li Hanqing Li Kun Luo Yuying Wang Peng Yan Fei Hu Fang Zhang Yele Sun Dongjie Shang Chunsheng Liang Dongmei Zhang Jing Wei Tong Wu Xiaoai Jin Xinxin Fan Maureen Cribb Marc L.Fischer Markku Kulmala Tuukka Pet?j? State Key Laboratory of Remote Sensing Science College of Global Change and Earth System ScienceBeijing Normal University ESSIC and Department of Atmospheric Science University of MarylandCollege Park State Key Laboratory of Clean Energy Utilization Zhejiang University School of Atmospheric Physics Nanjing University of Information Science and Technology Meteorological Observation Center China Meteorological Administration State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Lawrence Berkeley National Laboratory Institute for Atmospheric and Earth System Research/Physics Faculty of ScienceUniversity of Helsinki Aerosol and Haze Laboratory Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Joint International Research Laboratory of Atmospheric and Earth System Sciences School of Atmospheric Sciences Nanjing University

A new mechanism of new particle formation(NPF) is investigated using comprehensive measurements of aerosol physicochemical quantities and meteorological variables made in three continents,including beijing,China;the Southern Great Plains site in the USA;and SMEAR Ⅱ Station in Hyytiala,Finland.D espite the considerably different emissions of chemical species among the sites,a common relationship was found between the characteristics of NPF and the stability *** stability parameter(ζ=Z/L,where Z is the height above ground and L is the Monin-Obukhov length) is found to play an important role;it drops significantly before NPF as the atmosphere becomes more unstable,which may serve as an indicator of nucleation *** the atmosphere becomes unstable,the NPF duration is closely related to the tendency for turbulence development,which influences the evolution of the condensation ***,the unstable atmosphere may dilute pre-existing particles,effectively reducing the condensation sink,especially at coarse mode to foster *** new mechanism is confirmed by model simulations using a molecular dynamic model that mimics the impact of turbulence development on nucleation by inducing and intensifying homogeneous nucleation events.

关键词： new particle formation turbulence development molecular dynamic

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Disciplinary structure and development strategy of physical geography in China

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Journal of Geographical Sciences 2022年第9期32卷 1642-1653页

作者： CHEN Fahu WU Shaohong LIU Hongyan YANG Xiaoyan LIU Jianbao State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchCASBeijing100101China Alpine Paleoecology and Human Adaptation Group(ALPHA) Institute of Tibetan Plateau ResearchCASBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China College of Urban and Environmental Sciences Peking UniversityBeijing100871China College of Earth and Environmental Sciences Lanzhou UniversityLanzhou730000China

Physical geography,one of the branches of geography,is the basic discipline of geographic *** it is the scientific foundation of ecology,environmental science and other related *** geography focuses on spatial characteristics,evolution and regional differentiation of the earth’s *** the new period of rapid development of social economy,and science and technology,physical geography is more closely and widely connected with human geography and,information *** paper analyzed the forming process of the physical geography,expressed sub-discipline structure of integrated physical geography,sectoral physical geography,human living-environment geography,and proposed the development strategy of physical geography and its sub-branch disciplines,key priority of development goals and directions in China.

关键词： physical geography disciplinary structure development strategy

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