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2024 IEEE International Conference on Computational electromagnetics, ICCEM 2024

作者： Li, Hanpeng Chen, Xiaomin Li, Hangang Ma, Jian Ye, Xuchao Song, Lixin Zhang, Taotao Zhong, Weizhi Zhu, Qiuming Nanjing University of Aeronautics and Astronautics College of Electronic and Information Engineering Nanjing211106 China Aviation Key Laboratory of Science and Technology On Aero Electromechanical System Integration Nanjing211106 China State Key Lab. of Complex Electromagnetic Environment Effects On Electronics and Information System Luoyang471003 China

ISBN: (纸本)9798350383317

Unmanned aerial vehicles (UAVs) have enabled the unmanned management of water areas. Path loss (PL) serves as a critical factor that affects the UAV communication quality. In this work, a PL model for UAV channel in water scenarios is proposed, aiming to explore the multidimensional relationship between transceiver distance, carrier frequency, UAV height, and PL by constructing an Artificial Neural Network (ANN). Moreover, channel measurements are conducted in a river area, and the obtained data are analyzed using the proposed ANN model as well as the close-in (CI) model. The analysis results demonstrates that the PL increases initially and then declines as the UAV height increases. The proposed ANN model has higher prediction accuracy than the classic empirical model, and can achieve precise prediction of the PL in water scenarios. © 2024 IEEE.

关键词： Neural networks

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The enhanced aerosol deposition by bipolar corona discharge arrays

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Plasma Science and technology 2021年第6期23卷 83-88页

作者： Jiacheng LI Zhongzheng HUANG Dawei LIU Kuanlei ZHENG State Key Lab of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China School of Electrical and Information Engineering Wuhan Institute of TechnologyWuhan 430205People’s Republic of China

The corona discharges provide an efficient way to induce precipitation or eliminate fog by increasing ion density in the open *** this paper,one bipolar corona discharge array(positive and negative high voltage coupled simultaneously)which can generate high densities of positive and negative ions is *** comparison between bipolar corona discharge array and unipolar corona discharge array(positive or negative coupled only)indicates that bipolar corona discharge array can generate~3 times higher ion density than unipolar corona discharge *** charged aerosols are produced through collisions between ions and *** collision rate between aerosols is increased substantially by the attractive forces between positively and negatively charged *** deposition of aerosols induced by bipolar discharges is 25.7%higher than that of unipolar discharges at the humidity super-saturation ***,the bipolar corona discharge system is a new option for the large scale ion sources used for artificial weather modification.

关键词： corona discharges charged aerosols bipolar discharges

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Design and Analysis of a Novel Miniaturized Ultra-Thin Wide-Band Metamaterial Absorber

Design and Analysis of a Novel Miniaturized Ultra-Thin Wide-...

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2023 International Applied Computational electromagnetics Society Symposium, ACES-China 2023

作者： Ma, Jingnan Li, Yan Li, Erping School of Electronics and Information Engineering Hebei University of Technology Tianjin China China Jiliang University Key Lab. of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province China Zhejiang China Zhejiang University Key Laboratory of Advanced Micro-Nano Electronic Device and Smart Systems and Applications Zhejiang China

ISBN: (纸本)9781733509657

The volume of existing metamaterial absorber (MMA) is not small enough to be applied in miniaturized devices such as chip level. To solve this problem, a miniaturized ultrathin wide-band MMA is proposed in this paper. The thickness of proposed MMA is 1.1mm with a absorption rate of 99.6% at 19.7GHz. This paper also analyzes the influence of parameters of the proposed MMA on the absorption performance and proves that it has a certain tunability of the absorption band. By comparing with other works, the MMA proposed in this paper realizes the miniaturization of the structure while ensuring ultra-wideband. This benefit offers a novel approach to address the problem of difficult loading electromagnetic shielding structures in miniaturized chip designs. © 2023 Applied Computational electromagnetics Society (ACES).

关键词： electromagnetic shielding

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An Accurate Equivalent Circuit Model for Non-Intrusive electromagnetic Energy Harvester

An Accurate Equivalent Circuit Model for Non-Intrusive Elect...

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Power Electronics and Application Symposium (PEAS), IEEE International

作者： Liwen Hou Han Peng State Key Lab of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

High-frequency power electronic switching devices generate significant high-frequency magnetic fields in their surrounding space. High-frequency magnetic field energy harvesting devices offer higher output power density, allowing for smaller energy harvesting device volumes and portable installations, compared with grid frequency energy harvesters. Currently, research on the energy harvesting of high-frequency magnetic fields is relatively limited. The establishment of an accurate equivalent circuit model for high-frequency magnetic energy harvesters remains incomplete. Existing transformer models and inductance models are not entirely applicable. Calculating the AC coil resistance caused by skin effect and proximity effect, as well as the additional losses generated by eddy currents within the magnetic core, parasitic capacitance, and AC inductance parameters are highly related with the actual structure and design of the harvester. This paper designs a rectangular magnetic core structure and analyzes the equivalent circuit for high-frequency energy harvesting. Experimental parameter extraction is conducted to validate the correctness of the equivalent circuit model, demonstrating its effectiveness and accuracy.

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Influence Study of the Anisotropic Scattering and Solar Radiation on the Radiation Working Performance of Liquid Droplet Radiator

SSRN

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SSRN 2024年

作者： Fei, Yiheng Fu, Jianghan Wang, Chenglong Tian, Wenxi Guanghui, S.U. Qiu, Suizheng Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China

The Liquid Droplet Radiator (LDR), a lightweight frameless radiant heat rejection system, is widely regarded as the optimal heat rejection solution for megawatt-scale space nuclear power systems. The LDR dissipates heat to space through its droplet layer, which plays a crucial role in determining its radiative rejection capacity. Radiation beams undergo a series of emission, scattering, and absorption processes within the layer before being emitted into space. Prior studies typically assume isotropic scattering in this process. However, this study introduces a 3D model of the LDR layer based on Mie theory and Monte-Carlo methods to investigate the impact of anisotropic scattering and solar radiation. Our calculations reveal that the working fluid exhibits strong forward anisotropic scattering characteristics. Under the anisotropic assumption, the heat rejection capability of the LDR is 27-33% higher compared to the isotropic assumption. Regarding the temperature distribution within the LDR, under the anisotropic assumption, the layer's temperature is 6 K lower at the XY boundary surface and 3 K higher at the layer median, as opposed to the isotropic assumption. We introduce the concept of the probability of a light beam escape to elucidate the distinct beam transmission mechanisms and temperature distribution. When the distance between the LDR and the sun is in the vicinity of 1 AU, the impact of solar radiation on the LDR's ability to operate is on the order of 1E-5, which is almost negligible. This study provides a theoretical foundation for calculating the heat rejection capacity during the LDR design phase. © 2024, The Authors. All rights reserved.

关键词： Solar radiation

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Low Temperature Plasma Sources for Effective Inactivation of Pathogenic Microbial Aerosols

Low Temperature Plasma Sources for Effective Inactivation of...

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2021 IEEE International Conference on Plasma Science, ICOPS 2021

作者： Liu, Dawei Huazhong University of Science and Technology State Key Lab of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering WuHan430074 China

ISBN: (纸本)9781665432276

In order to develop the LTP air filtration system which can effectively inactivate PMA, we studied the bioche mical mechanism of inactivating pathogenic microorganisms by LTP, and the physical process of charging and adsorption of PMA by LTP, and on this basis, we developed an efficient LTP source for effective inactivation of PMAs. The scalab.e prototype plasma air filtration system effectively killed all the bacteria within the inter cepted pathogenic aerosols. © 2021 IEEE.

关键词： Aerosols

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Obtaining frequency-time diagram from perturbation signal-time diagram 7

Obtaining frequency-time diagram from perturbation signal-ti...

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7th International Conference on Physics, Mathematics and Statistics, ICPMS 2024

作者： Liu, Xiaoyuan Zhang, Yuxin Dai, Runrui Lai, Zongqiang Qiu, Huibin Shen, Chengshuo Weng, Huang Wu, Shengfa Zheng, Wei Zhang, Wei Liang, Wenxiang Han, Qianhao Li, Xiaobin Liu, Lihuan Shi, Chunhui Xu, Ting Zhang, Haotian Fan, Jiayu Yu, Meiping Tao, Jiajun Jiangxi Province Key Laboratory of Fusion and Information Control Department of Physics Nanchang University Nanchang330031 China NCU-ASIPP Magnetic Confinement Fusion Joint Lab Institute of Fusion Energy and Plasma Application Nanchang University Nanchang330031 China International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China

In the field of nuclear fusion energy development, magnetic confinement tokamak reactors, which use strong magnetic fields to confine high-temperature plasmas, are crucial for sustainable and clean fusion energy. Disruption caused by plasma instability can terminate the fusion reaction and even cause irreparable damage to the equipment. Therefore, a thorough understanding of the underlying physical mechanisms is essential for predicting and preventing plasma disruption. The recently proposed analytical theory of plasma disruption may predict and prevent plasma disruption, but its validation requires the frequency-time signals. The Heavy Ion Beam Probe (HIBP) can provide such signals, however, because its scarcity in the world, particularly in China, it is necessary to develop more suitable methods. Here we show a new approach that employs Fast Fourier Transform (FFT) on magnetic perturbation signals to obtain frequency-time diagrams. We successfully applied this algorithm to acquire the frequency-time diagram of the J-TEXT-1054560 discharge. This new method offers an effective tool for validating the plasma disruption theory, overcoming the limitations of traditional techniques and providing a crucial methodological basis for understanding and predicting plasma disruption. This new analytical approach will accelerate the advancement of fusion technology. © Published under licence by IOP Publishing Ltd.

关键词： Heavy ions

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Excess Activity Tuned by Distorted Tetrahedron in CoMoO_(4) for Oxygen Evolution

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Energy & Environmental Materials 2024年第1期7卷 247-252页

作者： Hengbo Xiao Kai Chi Hongxia Yin Xiangji Zhou Pengxiang Lei Peizhi Liu Jiakun Fang Xiuhong Li Songliu Yuan Zhen Zhang Yaqiong Su Junjie Guo Lihua Qian School of Physics Huazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Material Chemistry for Energy Conversion and Storage School of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Chemistry and Chemical Engineering Hubei University of TechnologyWuhan 430068China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China State Key Lab of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Mechanical Engineering Hubei University of TechnologyWuhan 430068China Department of Stomatology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430074China School of Chemistry Xi'an Jiaotong UniversityXi'an 710049China

Oxygen vacancies enable modulating surface reconstruction of transition metal oxides containing metal-oxygen polyhedrons into metallic oxyhydroxide for oxygen evolution reaction(OER),while revealing reconstructing mechanism is stuck by the requirement to precisely control exact sites of these ***,oxygen vacancies are localized only within MoO_(4)tetrahedrons rather than CoO_(6)octahedrons in CoMoO_(4)catalyst,guaranteeing coherent reconstruction of CoO_(6)octahedrons into pure CoOOH with tunable activities for ***,distorted tetrahedron accelerates the dissolution of Mo atoms into alkaline electrolyte,triggering spontaneous transition of partial CoMoO_(4)into Co(OH)_(2).CoO_(6)octahedrons in both CoMoO_(4)and Co(OH)_(2)can transform pure CoOOH completely at lower potential,resulting in excess intrinsic activity whose summit is identified by overpotential at 10 mA cm^(-2)with 22.9%reduction and Tafel slope with 65.3%***-defined manipulation over the distorted polyhedrons offers one versatile knob to precisely modulate electronic structure of oxide catalysts with outstanding OER performance.

关键词： metal-oxygen polyhedron oxygen evolution reaction oxygen vacancy Raman spectroscopy

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Fabrication and characterization of mullite fiber-based porous ceramics with mixed fiber lengths for high-temperature gas filtration

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Ceramics International 2025年

作者： Zheng, Dazhi Zhu, Ruijian Hu, Yuwen Liang, Shiou Sun, Huiying Wang, Zengmei State Key Laboratory of Engineering Materials for Major Infrastructure Jiangsu Key Lab. of Construction Materials School of Materials Science and Engineering Southeast University Nanjing211189 China School of Materials Science and Engineering Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Nanjing Institute of Technology Nanjing211167 China

The emissions and particulate pollutants (PM) from industrialization and other human activities have become a significant threat to human health. Researchers have experimented with various fiber-bonded filters, but there are still relatively few products with good high-temperature resistance. In this paper, a fiber-bonded porous ceramic with high porosity was prepared by vacuum filtration combined with freeze-drying using two homemade mullite fibers with different length-to-diameter ratios as raw materials and mullite sol as binder. When the content of fine fibers is 40 %, the product has a better overall performance, its density is 0.63g/cm3, porosity is 74 %, strength is 0.77 MPa, thermal conductivity is 0.153 W m−1 K−1. When the airflow rate of 2 L/min, the pressure drop is 80 Pa, the filtration efficiency of about 99 %, the QF is 0.08 pa−1, The mullite fiber-bonded porous ceramics prepared through a simple process exhibit excellent filtration performance, offering a wide range of potential applications. © 2025

关键词： Thermal conductivity of gases

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Model Predictive Control for Automatic Operation of Space Nuclear Reactors: Design, Simulation, and Performance Evaluation

SSRN

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SSRN 2023年

作者： Fu, Jianghan Jin, Zhao Dai, Zhiwen Su, Guanghui Wang, Chenglong Tian, Wenxi Qiu, Suizheng Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China

Space nuclear reactors possess the inherent benefits of independence from solar energy and the capability to withstand intricate external circumstances. Consequently, the establishment of a dependable automatic control system assumes utmost significance. In this paper, a high-fidelity nonlinear space thermionic nuclear reactor system model is established. An automatic control system with a model predictive control (MPC) controller is designed based on the system. In the case of a nuclear power step response, the MPC controller achieves an overshoot of 0.07% and a settling time of 0.65s. For an electric power step response, the MPC controller yields an overshoot of 0.28% and a settling time of 36.6s. These control performances are better than those achieved by the PID controller. In power tracking control, the MPC controller demonstrates virtually error-free tracking performance. When external reactivity disturbances are introduced, the MPC controller swiftly compensates for the disturbances at the desired level. © 2023, The Authors. All rights reserved.

关键词： Model predictive control

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