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2024 IEEE International Conference on Control Science and systems Engineering, ICCSSE 2024

作者： Zheng, Xiao Peng, Xiaodong Guo, Zhiyuan Qiang, Huimin Zhao, Junbao University of Chinese Academy of Science Laboratory of System Simulation and Concurrent Design Technology National Space Science Center Chinese Academy of Sciences Beijing China Beijing Remote Sensing Information Institute Beijing China

ISBN: (纸本)9798331517199

Marine moving ship target search has great application demand and development prospects in marine surveillance, marine search and rescue, customs anti-smuggling, and other aspects. Satellites are a vital means of searching for marine moving targets. Ground coverage for imaging satellites is relatively limited;the vast marine area makes searching for marine moving ships challenging. Target position prediction, used as the guidance information for satellite detection to reduce the uncertainty of the target position and improve search efficiency, is an essential approach to achieving target optimization search. This paper proposes a target position prediction method based on joint learning of multi-source factors for optimal satellite search of marine moving targets. Firstly, it analyzes the characteristics of marine moving targets and the factors affecting motion. Then, it puts forward the motion prediction model based on a deep neural network, integrating multifactor, like the state of the moving target, environmental attributes such as nautical charts, meteorology and hydrology, and kinematic constraints, to predict the target positional distribution probability. Finally, the target search strategy based on the maximum sum of the distribution probabilities of the satellite coverage area is adopted to improve target detection probability. The experiment results show that the prediction method can realize the target positional distribution probability prediction, reduce the uncertainty search when making the satellite search plan, and improve efficiency. © 2024 IEEE.

关键词： Deep neural networks

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Tailoring conductive network Zn@NPC@MWCNTs nanocomposites derived from ZIF-8 as high-performance electromagnetic absorber for the whole X-Band

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Defence technology（防务技术） 2023年第5期23卷 189-200页

作者： Shi-bin Lu Ying Meng Hai-bo Wang Xian-wei Jiang Jin Yang Ning Wei Lin Jin Li-juan Wan Hao Tang Qian-qian Hou Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal UniversityHefei230601PR China Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province Hefei Normal UniversityHefei230601PR China

A porous 3D cross-linked conductive network pierced by multi-wall carbon nanotubes(MWCNTs) was successfully designed from zeolitic imidazolate framework-8(ZIF-8). Zn@NPC@MWCNTs composites were tailored by the facile regulating the mass ratios and thermal annealing treatment. Due to the combination of less eddy current loss and dielectric loss together with multiple reflection attenuation caused by a unique structure. With a 10 wt% filler loading, the Zn@NPC@MWCNTs composites carbonized at 800℃ show two high reflection loss(RL) values with different thicknesses. An RL value is-53.18 dB with 4.09 mm thickness in the C-Band(4-8 GHz), and a minimum RL can reach-74.83 d B(10.8 GHz)with a matching thickness of 2.749 mm. The effective absorption bandwidth is 4 GHz(from 8 to 12 GHz,RL ≤-10 d B), which just covers the full X-band. Low cost and easy preparation can also provide advantages to develop MOF-based materials as effective EMW absorbents.

关键词： ZIF-8 Electromagnetic wave absorption X-band C-Band

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Numerical simulation of Flow Boiling Heat Transfer in Helical Tubes Under Marine Conditions 23rd

Numerical Simulation of Flow Boiling Heat Transfer in Helica...

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23rd Pacific Basin Nuclear Conference, PBNC 2022

作者： Yuan, Leqi Cheng, Kun Bian, Haozhi Liao, Yaping Jiang, Chenxi Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Heilongjiang Harbin China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

ISBN: (纸本)9789819910229

Lead-based cooled reactors in most countries and some small reactors at sea use helical tube steam generators. Compared with U-tubes, the convection heat transfer coefficient in the spiral tube is higher, the structure is more compact, and the secondary flow is generated under the action of centrifugal force and gravity, which can achieve the effect of wetting the inner wall of the tube. However, due to the importance of the steam generator in the reactor and the complexity of the flow and boiling in the helical tube, the aggregation behavior of bubbles, the distribution of the two-phase interface and the secondary flow in the tube will significantly affect the heat transfer characteristics, so the gas-liquid phase in the tube is studied. Distribution, changes in heat transfer coefficients, and fluid flow characteristics are very important. In order to study the boiling heat transfer characteristics of helical once-through steam generators under static and marine conditions to provide safe and reliable energy supply for offshore facilities such as marine floating, this study uses STAR-CCM+ software, VOF method and Rohsenow boiling model to study the heat transfer capacity and flow characteristics of flow boiling in a helical tube under swaying and tilting conditions. The gas-liquid phase distribution characteristics, secondary flow variation characteristics and convective heat transfer coefficient of the fluid under different swing functions and inclined positions are obtained by numerical calculation, and the law of physical parameters changing with the cycle is found. The research results show that the secondary flow and heat transfer capacity in the tube change with the cycle, and the change is most obvious at the tube length of 0.8m. 5% of the normal condition;when the inclination angle is 45°, the maximum increase of the convection heat transfer coefficient is 16.8%, and the maximum decrease is 6.6%. © 2023, The Author(s).

关键词： Computational fluid dynamics

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A Position Probability Prediction Method of Marine Moving Targets for Optimization Search by Satellite

A Position Probability Prediction Method of Marine Moving Ta...

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IEEE International Conference on Control Science and systems Engineering (CCSSE)

作者： Xiao Zheng Xiaodong Peng Zhiyuan Guo Huimin Qiang Junbao Zhao Laboratory of System Simulation and Concurrent Design Technology (National Space Science Center Chinese Academy of Sciences) University of Chinese Academy of Science Beijing China Beijing Remote Sensing Information Institute Beijing China

ISBN: (数字)9798331517199

ISBN: (纸本)9798331517205

Marine moving ship target search has great application demand and development prospects in marine surveillance, marine search and rescue, customs anti-smuggling, and other aspects. Satellites are a vital means of searching for marine moving targets. Ground coverage for imaging satellites is relatively limited; the vast marine area makes searching for marine moving ships challenging. Target position prediction, used as the guidance information for satellite detection to reduce the uncertainty of the target position and improve search efficiency, is an essential approach to achieving target optimization search. This paper proposes a target position prediction method based on joint learning of multi-source factors for optimal satellite search of marine moving targets. Firstly, it analyzes the characteristics of marine moving targets and the factors affecting motion. Then, it puts forward the motion prediction model based on a deep neural network, integrating multifactor, like the state of the moving target, environmental attributes such as nautical charts, meteorology and hydrology, and kinematic constraints, to predict the target positional distribution probability. Finally, the target search strategy based on the maximum sum of the distribution probabilities of the satellite coverage area is adopted to improve target detection probability. The experiment results show that the prediction method can realize the target positional distribution probability prediction, reduce the uncertainty search when making the satellite search plan, and improve efficiency.

关键词： Satellites Uncertainty Object detection Kinematics Predictive models Search problems Satellite navigation systems Marine vehicles Modeling Optimization

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Magnetic and magnetocaloric effect in a stuffed honeycomb polycrystalline antiferromagnet GdInO_(3)

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Chinese Physics B 2022年第6期31卷 656-662页

作者： Yao-Dong Wu Wei-Wei Duan Qiu-Yue Li Yong-Liang Qin Zhen-Fa Zi Jin Tang Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province Anhui Province Key Laboratory of Simulation and Design for Electronic Information Systemand School of Physics and Materials EngineeringHefei Normal UniversityHefei 230601China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field LaboratoryHFIPSAnhuiChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China

The magnetic and magnetocaloric properties were studied in a stuffed honeycomb polycrystalline antiferromagnet GdInO_(3).The onset temperature of antiferromagnetic ordering was observed at~2.1 *** thermal and magnetic hystereses suggest a reversible magnetocaloric effect(MCE)in the GdInO_(3) *** the magnetic field changes of 0 kOe-50 kOe and 0 kOe-70 kOe,the maximum magnetic entropy change values are 9.65 J/kg·K and 18.37 J/kg·K,respectively,near the liquid helium temperature,with the corresponding relative cooling power values of 115.01 J/kg and211.31 J/*** MCE investigation of the polycrystalline GdInO_(3) serves to illuminate more exotic properties in this frustrated stuffed honeycomb magnetic system.

关键词： GdInO_(3) magnetization magnetocaloric effects stuffed honeycomb antiferromagnet

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Broadband Wide-Angle Linear-to-Circular Polarization Converter Based on Metal Strips Loaded Metasurface

Broadband Wide-Angle Linear-to-Circular Polarization Convert...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Wang, Jingwen Deng, Shasha Chen, Weidong Zhang, Zhongxiang Chen, Chang University of Science and Technology of China School of Information Science and Technology Hefei230031 China Hefei Normal University Key Laboratory of Simulation and Design for Electronic Information System Hefei230601 China

ISBN: (纸本)9781665452366

A transmissive broadband wide-angle linear-to-circular polarization converter based on metal strips loaded metasurface is proposed in this paper. The converter is composed of three metallic layers separated by dielectric substrates and the metal strips printed on each layer keep orthogonal to each other. To further investigate the operating mechanism of the design, equivalent circuit models are presented. Moreover, the converter is verified to be effective in polarization conversion through the full-wave simulation. With the insertion loss less than 2 dB and 3 dB, the simulation 3-dB axial ratio (AR) bandwidth keeps 67% and 76%, respectively. Furthermore, at an increased incident angle of 40°, the device can still maintain an AR bandwidth over 47% at 2 dB insertion loss, which manifests the validity and rationality of the converter design. © 2022 IEEE.

关键词： Strip metal

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A Band Stop Decoupling Structure for Circularly Polarized Antennas With Different Intervals

A Band Stop Decoupling Structure for Circularly Polarized An...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Ding, Yuhang Deng, Shasha Chen, Weidong Zhang, Zhongxiang Chen, Chang University of Science and Technology of China School of Information Science and Technology Hefei230031 China Hefei Normal University Key Laboratory of Simulation and Design for Electronic Information System Hefei230601 China

ISBN: (纸本)9781665452366

In this paper, a novel band stop decoupling structure (BSDS) for circularly polarized microstrip antenna array with different intervals to realize mutual coupling reduction is proposed. The BSDS is composed of complementary split-rings resonator (CSRRs) and split-rings resonator (SRRs), where the CSRRs block TM waves by electric resonance and the SRRs block TE waves by magnetic resonance, respectively. The proposed design is verified by the simulation and the results indicate that the isolation enhancement more than 35 dB can be obtained at the center frequency of 3.4 GHz when the center spacing is 0.37 λ0. Futhermore, when the center spacing reduces to 0.26 λ0, the mutual coupling remains below 25 dB. Besides, the BSDS can improve the radiation pattern offset without affecting the gain and the backward radiation of antennas. © 2022 IEEE.

关键词： Magnetic resonance

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Magnitude,distribution and temporal trend of nitrous oxide emissions from China's natural soils over 1980–2022

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Science China Earth Sciences 2025年第4期68卷 1074-1085页

作者： Songbai HONG Zimeng LI Mingsong TANG Fa LI Yitong YAO Yanzi YAN Mingzhu HE Xuhui WANG Hui ZENG Shilong PIAO School of Urban Planning and Design Shenzhen Graduate SchoolPeking UniversityShenzhen518055China Key Laboratory of Earth Surface System and Human-Earth Relations Ministry of Natural Resources of ChinaShenzhen Graduate SchoolPeking UniversityShenzhen518055China Institute of Carbon Neutrality Sino-French Institute for Earth System ScienceCollege of Urban and Environmental SciencesPeking UniversityBeijing100871China Department of Earth System Science Stanford UniversityStanfordCA94305USA Division of Geological and Planetary Sciences California Institute of TechnologyPasadenaCA91125USA Department of Soil and Environment Swedish University of Agricultural SciencesUppsala75007Sweden Joint International Research Laboratory of Catastrophe Simulation and Systemic Risk Governance Beijing Normal UniversityZhuhai519087China School of National Safety and Emergency Management Beijing Normal UniversityZhuhai519807China

Soils represent the largest contributor to global nitrous oxide(N_(2)O)***,current research efforts predominantly focus on N_(2)O emissions from agricultural soils,while studies on N_(2)O emissions from natural soils,another significant source,remain *** this study,we explored the magnitude,spatiotemporal dynamics,and drivers of N_(2)O emissions from China's natural soils over the period 1980–2022 via machine learning and a compiled novel dataset of 319 field *** results revealed that the N_(2)O flux per unit area was generally higher in the southeast compared to the northwest,and higher in forests than in *** spatial and biome heterogeneity was strongly regulated by local hydrothermal conditions and nitrogen *** averaged N_(2)O emissions over the study period were 646.2±27 Gg N_(2)O yr^(-1),with approximately equivalent contributions from forests and ***,there exhibited a significant and increasing trend from 1980 to 2022,with a rate of 2.7 Gg N_(2)O yr^(-2).Such an increase was primarily driven by the expansion of forested area and elevated nitrogen *** data-driven study presents a long-term and gridded estimate of N_(2)O emissions from China's natural soils,emphasizing the need for future research on changes of greenhouse gas emissions induced by land use change and nitrogen deposition.

关键词： Nitrous oxide Spatiotemporal dynamics Nitrogen deposition Forests Grasslands Data-driven estimates

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The Improvement and Validation of Laser Induced Fluorescence technology on Temperature and Concentration Measurement

SSRN

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SSRN 2024年

作者： Zhang, Qi Wang, Haoyu Li, Junlong Zhou, Yi Liu, Zhenhai Qi, Feipeng Li, Dongyang Tan, Sichao Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin150001 China

Laser induced fluorescence (LIF) is characterized as a non-insertion and whole-field measuring technology for the thermal-hydraulic analysis. This paper presents the details of LIF, including the basic principle, the main apparatus and the data process methods. The effects of the inhomogeneous laser sheet and ambient light are eliminated by the discretization of the camera pixels. A new data process method base on the empirical fitted polynomial is developed. The additional calibration test and the empirical fitted polynomial are combined for the simplification and optimization of the data process method. The results shows that the deviation in temperature measurement is within 0.5 ℃ for the improved method, and is within 1.0 ℃ for the conventional method. The concentration measurement error is within 5.67% for the improved method, and is about 7.10% for the conventional method. The new method proposed by this work makes LIF technology more convenient and accurate. © 2024, The Authors. All rights reserved.

关键词： Fluorescence

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Study on Diffusion and Migration Characteristics of Impurities in Secondary Side of Simplified U-Tube Steam Generator

SSRN

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SSRN 2023年

作者： Li, Meng Cheng, Kun Wen, Jiming Tian, Ruifeng Fundamental Science on Nuclear Safety Simulation Technology Laboratory Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

In the operation process of nuclear power system, leakage accidents of main and auxiliary condensers are easy to occur, which leads to seawater entering the secondary loop from the condenser, and impurities such as Cl- enter the steam generator with the feed water of the secondary loop, and are enriched near the heat transfer tube. It is easy to cause wear and corrosion of steam generator heat transfer tube, which threatens the safety of nuclear power plant. In order to study the migration and diffusion process of impurity Cl- in the secondary side of steam generator, a multi-bundle three-dimensional physical model of fluid-solid coupling heat transfer in the primary and secondary loop of steam generator and heat transfer tube was established respectively. The fluid flow and heat transfer process between Ushaped tube bundles were simulated numerically to reveal the distribution law of key thermo-hydraulic parameters between Ushaped tube bundles, such as volume vapor fraction, temperature, velocity, etc. The diffusion and migration of Cl- in two-phase flow were also investigated. The influence of thermalhydraulic parameters on impurity migration, two-phase flow in the secondary side and effective diffusion coefficient of chloride ions on chloride ion concentration distribution were *** concentration of chloride ions changes with the change of effective diffusion coefficient of chloride ions. The effective diffusion coefficient of chloride ions is affected by the boiling intensity of coolant and the flow velocity of coolant. The synergistic effect of the boiling intensity of coolant and the flow velocity of coolant affects the migration and diffusion of chloride *** above phenomena may lead to impurity deposition and stress corrosion of heat transfer tubes near the surface. © 2023, The Authors. All rights reserved.

关键词： Steam generators

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