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Chinese Chemical Letters 2024年第8期35卷 25-35页

作者： Yatian Deng Dao Wang Jinglan Cheng Yunkun Zhao Zongbao Li Chunyan Zang Jian Li Lichao Jia School of Materials Science and Engineering State Key Lab of Material Processing and Die&Mould TechnologyHuazhong University of Science and TechnologyWuhan 430074China College of Science Qiongtai Normal UniversityHaikou 571127China Kunming Sino-Platinum Metals Catalyst Co. Ltd.Kunming 650106China State Key Laboratory of Advanced Electromagnetic Technology Huazhong University of Science and TechnologyWuhan 430074China

Catalyst with high performance has drawn increasing attention recently due to its significant advantages in chemical reactions such as speeding up the reaction,lowering the reaction temperature or pressure,and proceeding without itself being *** the superior catalytic performance of precious metal catalysts,transition metal oxides offer a promising route for substitution of precious metals in catalysis arising from their low cost,intrinsic activity and sufficient ***-type oxide SmMn_(2)O_(5) exhibits a unique crystal structure containing double crystalline fields,and nowadays is used widely as the catalyst in different chemical reactions,including the reactions of vehicle emissions reduction and oxygen evolution reaction,gas sensors,and metal-air batteries,promoting attention in catalytic perfor-mance *** our knowledge,there is no review article covering the comprehensive informa-tion of SmMn2 O 5 and its *** we review the recent progress in understanding of the crys-tal structure of SmMn_(2)O_(5) and its basic physical *** then summarize the catalytic sources of SmMn_(2)O_(5) and reaction mechanisms,while the strategies to improve catalytic performance of SmMn_(2)O_(5) are further ***,we provide a perspective on how to make further progress in catalytic applications.

关键词： Catalyst SmMn_(2)O_(5) Mullite-type oxide Catalytic oxidation Oxygen reduction reaction Oxygen evolution reaction Reaction mechanisms

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Failure Modes and Energy Handling Capability of ZnO Varistors with Different Electrode Edge Margins Stressed by Current Impulses 7

Failure Modes and Energy Handling Capability of ZnO Varistor...

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7th IEEE International Conference on High Voltage engineering and Application, ICHVE 2020

作者： Fang, Zhen Wang, Bowen Fu, Zhiyao State Key Lab. of Disaster Prev. Reduction for Power Grid Transmission and Distribution Equipment State Grid Hunan Electric Power Company Disaster Prevention and Reduction Center Changsha China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781728155111

ZnO varistors with different electrode edge margins were tested under 2 ms rectangular impulses and 4/10 µs impulses. A certain margin is necessary to be left between the electrode edge and the edge of the ZnO varistor so that the electrical performance, especially energy handling capability, will not be scattered and limited. Experiments have shown that ZnO varistors with 0.5 mm margin performed better than that with 0 mm, 0.3 mm and 1 mm margins on the whole. During the impulse test, some varistor samples failed. The failure modes under current impulses, including puncture, cracking and flashover were discussed. © 2020 IEEE.

关键词： Electrodes

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POLSAR LAND COVER CLASSIFICATION BASED on HIDDEN POLARIMETRIC FEATURES in ROTATION DOMAIN and SVM CLASSIFIER

POLSAR LAND COVER CLASSIFICATION BASED on HIDDEN POLARIMETRI...

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ISPRS Geospatial Week 2017

作者： Tao, Chen-Song Chen, Si-Wei Li, Yong-Zhen Xiao, Shun-Ping State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System School of Electronics Science and Engineering National University of Defense Technology Changsha410073 China

Land cover classification is an important application for polarimetric synthetic aperture radar (PolSAR) data utilization. Rollinvariant polarimetric features such as iH/Ani/α/Span are commonly adopted in PolSAR land cover classification. However, target orientation diversity effect makes PolSAR images understanding and interpretation difficult. Only using the roll-invariant polarimetric features may introduce ambiguity in the interpretation of targets' scattering mechanisms and limit the followed classification accuracy. To address this problem, this work firstly focuses on hidden polarimetric feature mining in the rotation domain along the radar line of sight using the recently reported uniform polarimetric matrix rotation theory and the visualization and characterization tool of polarimetric coherence pattern. The former rotates the acquired polarimetric matrix along the radar line of sight and fully describes the rotation characteristics of each entry of the matrix. Sets of new polarimetric features are derived to describe the hidden scattering information of the target in the rotation domain. The latter extends the traditional polarimetric coherence at a given rotation angle to the rotation domain for complete interpretation. A visualization and characterization tool is established to derive new polarimetric features for hidden information exploration. Then, a classification scheme is developed combing both the selected new hidden polarimetric features in rotation domain and the commonly used roll-invariant polarimetric features with a support vector machine (SVM) classifier. Comparison experiments based on AIRSAR and multi-temporal UAVSAR data demonstrate that compared with the conventional classification scheme which only uses the roll-invariant polarimetric features, the proposed classification scheme achieves both higher classification accuracy and better robustness. For AIRSAR data, the overall classification accuracy with the proposed classification schem

关键词： Land Cover Classification Polarimetric Feature Mining Polarimetric Synthetic Aperture Radar (PolSAR) Rotation Domain Support Vector Machine (SVM)

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Multi-temporal PolSAR crops classification using polarimetric-feature-driven deep convolutional neural network

Multi-temporal PolSAR crops classification using polarimetri...

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2017 International Workshop on Remote Sensing with Intelligent Processing, RSIP 2017

作者： Chen, Si-Wei Tao, Chen-Song State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Engineering National University of Defense Technology Changsha410073 China

ISBN: (纸本)9781538619902

Multi-temporal PolSAR data is suitable for crops classification and growth monitoring. It is still difficult to establish a classifier with good robustness and high generation over a long temporal acquisition duration. This work aims to provide a solution to this task by exploring benefits from both the target scattering mechanism interpretation and the advanced deep learning. A polarimetric-feature-driven deep convolutional neural network classification scheme is established. Comparison studies with multi-temporal UAVSAR datasets validate the efficiency and superiority of the proposal. © 2017 IEEE.

关键词： Classification (of information)

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Vibration analysis of motor stator

Vibration analysis of motor stator

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2014 2nd International Conference on Manufacturing engineering and technology for Manufacturing Growth, METMG 2014

作者： Yan, Rong Ge Feng, Xu Zhu, Li Hua Yang, Qing Xin Province-Ministry Joint Key Lab. of Electromagnetic Field and Electrical Apparatus Reliability Hebei University of Technology Tianjin 300130 China Tianjin Key Laboratory of Advanced Technology of Electrical Engineering and Energy Tianjin Polytechnic University Tianjin 300387 China

ISBN: (纸本)9783038350354

Motor vibration is one of the main causes of the motor noise, and the vibration of the motor also brings great harm for the safe and reliable operation of the motor load system. The vibration and noise level is one of the essential elements in evaluating the electrical machine's quality. Accurate calculation of the stator natural frequencies and harmonic response of an electrical machine is essential to the prediction of the vibration. This paper takes the common Y series induction motors as the sample. The motor is a complex electromechanical coupling system, which includes stator and rotor. The finite element analysis is used to study on the stator modal shapes and natural frequencies of the induction motor. Then this paper calculates the electromagnetic force by using the finite element method, and gets the spectrum distribution of the radial electromagnetic force. Thus it provides a good method for the motor design by predicting natural frequency and optimizing the motor parameters to avoid resonance. All of them provide theory fundamental basis and technical support for reducing vibration and noise of the motor. © (2014) Trans Tech Publications, Switzerland.

关键词： Stators

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Giant magnetostrictive freezing rain sensor

Giant magnetostrictive freezing rain sensor

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2014 2nd International Conference on Manufacturing engineering and technology for Manufacturing Growth, METMG 2014

作者： Yan, Rong Ge Jia, Yu Long Zhu, Li Hua Yang, Qing Xin Province-Ministry Joint Key Lab. of Electromagnetic Field and Electrical Apparatus Reliability Hebei University of Technology Tianjin 300130 China Tianjin Key Laboratory of Advanced Technology of Electrical Engineering and Energy Tianjin Polytechnic University Tianjin 300387 China

ISBN: (纸本)9783038350354

As a disastrous weather, hazards of freezing rain can not be ignored. The important thing to be solved at present is using advanced technology and material to correctly detect and improve the forecasting ability of freezing rain. Based on the damage of freezing rain and excellent properties of the giant magnetostrictive materials, this paper gives a giant magnetostrictive freezing rain sensor. When there is different thickness of freezing rain, natural frequency of the sensor will change. Resonance is regained by adjusting the frequency of the power. From natural frequency change, the thickness of the freezing rain can be known. Using COMSOL software, modal analysis of different thickness freezing rain for the giant magnetostrictive freezing rain sensor is studied. The results show that there is big difference in natural frequency with difference thickness of freezing rain, which is easy to achieve automatic frequency tracking and monitor. © (2014) Trans Tech Publications, Switzerland.

关键词： Natural frequencies

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Contribution of magnetostriction to transformer core vibration under DC bias

Contribution of magnetostriction to transformer core vibrati...

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2014 2nd International Conference on Manufacturing engineering and technology for Manufacturing Growth, METMG 2014

作者： Yan, Rong Ge Wang, Xi Feng Zhu, Li Hua Yang, Qing Xin Province-Ministry Joint Key Lab. of Electromagnetic Field and Electrical Apparatus Reliability Hebei University of Technology Tianjin 300130 China Tianjin Key Laboratory of Advanced Technology of Electrical Engineering and Energy Tianjin Polytechnic University Tianjin 300387 China

ISBN: (纸本)9783038350354

An important source of transformer core vibration is magnetostriction of the thin silicon-steel lamination. In the power grid, direct current (DC) may form by solar magnetic storms and DC transmission. Transformer core supersaturation and harmonic increase in current caused by DC bias will intensify magnetostriction and produce additional transformer core vibration. In order to obtain transformer core vibration under DC bias, the magnetization curve and magnetostriction characteristics of thin silicon-steel lamination are measured. Then, this paper establishes a numerical magneto-mechanical strong coupling model including magnetostrictive effect under DC bias for three-phase three-column dry transformers. On the basis of the proposed model, and the measured magnetic characteristics of the thin silicon-steel lamination, transformer core vibration under DC bias and no-load condition has been calculated. In order to verify the proposed model, transformer core vibration under DC bias and no-load condition is studied experimentally. Numerical calculation results together with experimental results confirm the validity of the proposed method. © (2014) Trans Tech Publications, Switzerland.

关键词： Finite element method

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Coupling effects of mechanical vibrations and thermal cycling on reliability of CCGA solder joints

Coupling effects of mechanical vibrations and thermal cyclin...

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作者： Ding, Ying Tian, Ruyu Wang, Xiuli Hang, Chunjin Yu, Fang Zhou, Ling Meng, Xiangang Tian, Yanhong Beijing Institute of Control Engineering Beijing100190 China State Key Lab. of Advanced Welding Production Technology Harbin Institute of Technology Harbin150001 China

The microstructures and crack propagation behavior of CCGA (ceramic column grid array) solder joints after sinusoidal vibration loading, random vibration loading, and thermal cycling test have been discussed in this study. The failure mechanism of solder joints was analyzed using an experimental method and finite element analysis. It was found that the failed solder joints mainly distributed at the peripheral area in the solder column arrays and the crack initiation was mainly caused by mechanical vibrations. The deformation of PCB (printed circuit board) introduced by mechanical vibrations brought the outermost solder columns in CCGA devices with significant stress concentration and induced the initiation of cracks. Furthermore, cracks propagated during the process of mechanical vibrations and thermal cycling. The cracks propagated rapidly and the solder joints finally failed. The structure of the PCB holder was improved to relieve the vibration response from the peripheral joints. No visible crack was found in the solder joints after the same mechanical vibrations and thermal cycling test. The reliability of solder joints have been greatly improved with the new PCB holder. © 2015 Elsevier Ltd. All rights reserved.

关键词： Vibrations (mechanical)

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Optimization of control parameters for PMSG-based wind farm and SVG considering subsynchronous interaction 8

Optimization of control parameters for PMSG-based wind farm ...

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8th Renewable Power Generation Conference, RPG 2019

作者： Liu, Yuming Huang, Biyue Sun, Haishun Zhang, Yi Han, Yingsheng Yu, Yongjun State Key Lab of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China State Grid Xinjiang Electric Power Research Institute Urumqi Xinjiang Uygur Autonomous Region830011 China

ISBN: (纸本)9781839531255

Recently, sub-synchronous oscillations (SSO) phenomena have occurred in direct-drive permanent magnetic synchronous generator (D-PMSG) based wind farms. The majority of wind farms have installed the static var generator (SVG) to improve the voltage stability. But some oscillation events showed that SVG have produced adverse effect to the system. There are distinct subsynchronous interactions (SSI) between PMSG-based wind turbines and SVG. Researches have pointed out that when connected to a weak grid the improper control parameter is the main course of the SSI. Therefore, the control parameter of the system need be optimized considering the SSI problems. The mathematical model the analytical transfer function is derived firstly. Then the stable and feasible region of SVG's and PMSG's control parameter are determined according to stability criterion. At last, some coordination methods for the control parameters are proposed considering the SSI problems, and the electromagnetic simulations is carried out to verify the correctness and effectiveness. © 2019 Institution of engineering and technology. All rights reserved.

关键词： Synchronous generators

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Electrical Behavior against Current Impulse in ZnO Varistor Ceramics with SiO2Addition 8

Electrical Behavior against Current Impulse in ZnO Varistor ...

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8th Annual International Conference on Material Science and engineering, ICMSE 2020

作者： Wang, Bowen Fang, Zhen Fu, Zhiyao Peng, Yongjing State Key Lab. of Disaster Prev. and Reduction for Pwr. Grid Transmission and Distribution Equipment State Grid Hunan Electric Power Company Disaster Prevention and Reduction Center Changsha410129 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hubei430074 China

SiO2 addition effect on electrical behaviour against current impulse in the ZnO varistors was investigated. SiO2 acts as a controller in ZnO grain growth, decreasing the grain size of ZnO from 8.87 to 5.86 µm, which in turn results in an increase in breakdown voltage E1mA from 192.77 to 252.57 V/mm. SiO2 has a significant influence on the current energy withstand capability and impulse aging characteristics. The results indicated that the SiO2 content was optimized at 1.5 mol%, exhibiting the best energy withstand capability of 332.03J/cm3 and clamping ratio of 1.71. © Published under licence by IOP Publishing Ltd.

关键词： Silica

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