期刊文献+
共找到1,001篇文章
< 1 2 51 >
每页显示 20 50 100
Fast measurement and prediction method for electromagnetic susceptibility of receiver
1
作者 CHEN Yan LU Zhonghao LIU Yunxia 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期275-285,共11页
Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequenc... Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone test.Firstly,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent analysis.Secondly,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the receiver.An experiment performed on a radar receiver confirms the reliability of the method proposed in this paper.It shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity model.Based on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized. 展开更多
关键词 electromagnetic susceptibility(emS) RECEIVER dualchannel multi-frequency nonlinear response frequency domain power domain
下载PDF
Influence of iron powder content on the electromagnetic and mechanical performance of soft magnetic geopolymer composite 被引量:1
2
作者 Tao Ma Gonghui Gu +1 位作者 Feng Chen Ning Wang 《Journal of Road Engineering》 2023年第3期288-299,共12页
In the induction heating of airport pavement to remove snow and ice,soft magnetic geopolymer composite(SMGC)can be used to gather the dissipated electromagnetic energy,thus enhancing the energy utilization efficiency.... In the induction heating of airport pavement to remove snow and ice,soft magnetic geopolymer composite(SMGC)can be used to gather the dissipated electromagnetic energy,thus enhancing the energy utilization efficiency.The aim of this work is to analyze the influence mechanism of iron powder content on the electromagnetic and mechanical performance of SMGC,so as to provide theoretical guidance for the design of soft magnetic layer within airport pavement structure.The results show that the increase of iron powder content reduces the resistance and magnetoresistance of SMGC by decreasing the content of non-magnetic phases between iron powder.However,the reduction of iron powder spacing also provides a shorter transmission path for the inter-particle eddy currents in the SMGC specimen,which enhances the exchange coupling between iron powder,thus increasing the electromagnetic loss.Therefore,the compatibility between magnetic permeability and electromagnetic loss should be considered comprehensively in the mix design of SMGC.In addition,although iron powder can enhance the mechanical properties of SMGC by improving the density of geopolymer matrix,the excessive amount of iron powder can lead to a weak interfacial transition zone between geopolymer matrix and iron powder.According to the induction heating results,optimized SMGC can improve the energy transfer efficiency of induction heating by 24.03%. 展开更多
关键词 Soft magnetic geopolymer Mechanical performance electromagnetic performance Induction heating Energy conversion efficiency
下载PDF
Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature 被引量:3
3
作者 Cuiping Li Dan Li +4 位作者 Shuai Zhang Long Ma Lei Zhang Jingwei Zhang Chunhong Gong 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期147-160,共14页
Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss.Consequently... Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss.Consequently,the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top priority.Herein,due to the high melting point,good electrical conductivity,excellent environmental stability,EM coupling effect,and abundant interfaces of titanium nitride(TiN)nanotubes,they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening process.Benefiting from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane(PDMS),enhanced polarization loss relaxations were created,which could not only improve the depletion efficiency of EMWA,but also contribute to the optimized impedance matching at elevated temperature.Therefore,the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature(298-573 K),while achieved an effective absorption bandwidth(EAB)value of 3.23 GHz and a minimum reflection loss(RLmin)value of−44.15 dB at 423 K.This study not only clarifies the relationship between dielectric loss capacity(conduction loss and polarization loss)and temperature,but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering. 展开更多
关键词 TiN nanotubes Interface engineering Polarization loss Impedance matching electromagnetic wave absorption performance
下载PDF
Refined disturbance observer based prescribed performance fixed-time control of high-speed EMS trains with track irregularities
4
作者 Yiran Xie Boyang Zhao Xiuming Yao 《High-Speed Railway》 2023年第3期171-178,共8页
High-speed Electromagnetic Suspension(EMS)train is continuously impacted by the irregularity of the track,which worsens the levitation performance of the train.In this paper,a composite control scheme for the EMS is p... High-speed Electromagnetic Suspension(EMS)train is continuously impacted by the irregularity of the track,which worsens the levitation performance of the train.In this paper,a composite control scheme for the EMS is proposed to suppress track irregularities by integrating a Refined Disturbance Observer(RDO)and a Prescribed Performance Fixed-Time Controller(PPFTC).The RDO is designed to estimate precisely the track irregularities and lumped disturbances with uncertainties and exogenous disturbances in the suspension system,and reduce input chattering by applying to the disturbance compensation channel.PPFTC is designed to converge the suspension air gap error to equilibrium point with prescribed performance by completing error conversion,and solve the fast dynamic issue of EMS.And the boundary of overshoot and steady-state is limited in the ranged prescribed.A theoretical analysis is conducted on the stability of the proposed control method.Finally,the effectiveness and reasonability of the proposed composite anti-disturbance control scheme is verified by simulation results. 展开更多
关键词 High-speed electromagnetic suspension train Track irregularity Refined disturbance observer Prescribed performance Fixed-time control
下载PDF
Damage characteristics of Cu−Cr−Zr alloy rail of electromagnetic railgun after simulated launch
5
作者 Ke-chang SHEN Qing-tao GONG +3 位作者 Zhong-yu SUN Hong-tu SUN Bin-jie MA Wei-min WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第8期2589-2604,共16页
The damage characteristics of different speed sections of Cu−Cr−Zr alloy rail after simulated launch were studied.The microstructure,morphologies and properties of samples were investigated by using XRD,XPS,EBSD,SEM,h... The damage characteristics of different speed sections of Cu−Cr−Zr alloy rail after simulated launch were studied.The microstructure,morphologies and properties of samples were investigated by using XRD,XPS,EBSD,SEM,hardness test,electrochemical test and DSC techniques.It was found that deposition layers were formed on the surfaces of the simulated launch samples.The thickness and surface roughness of these deposition layers increased with increasing the heat effect,suggesting a launch speed dependent damage degree of the arc ablation.The hardness variation of samples is attributed to the effects of the deposition layer and deformation hardening.The surface deposition layer affects corrosion resistance and crystalline characteristics,leading to changes in subsequent service performances.Additionally,the surface texture and plastic deformation ability of the samples are related to the recrystallization degree and deformation grain amount. 展开更多
关键词 Cu−Cr−Zr alloy electromagnetic railgun arc ablation microstructure performance
下载PDF
Effect of Electromagnetic Compound Treatment on Microstructure and Performance of Cemented Carbide
6
作者 WEI Liao YANG Yi +3 位作者 YANG Gang WU Mingxia WEI Can WUXiuli 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第5期1119-1126,共8页
In order to study the effect of electromagnetic compound treatment on the mechanical property, cutting performance and microstructure of cemented carbide, the samples were treated by a self-made electromagnetic compou... In order to study the effect of electromagnetic compound treatment on the mechanical property, cutting performance and microstructure of cemented carbide, the samples were treated by a self-made electromagnetic compound treatment device with different magnetic field strength(H=1, 1.25 and 1.5 T). The electromagnetic compound treatment method was proposed to couple pulsed magnetic field and pulsed current. The results show that after the pulsed magnetic field treatment, the values of the transverse rupture strength of the samples were respectively reduced by 21%, 20.6% and 20.1%;the cutting performance was decreased by about 4.5%, which means the tool life was decreased. After the electromagnetic compound treatment, the values of the transverse rupture strength of the rectangular samples were respectively increased by 8%, 8.6% and 9.5%, and the tool life was increased by 4.2%, 7% and 10.3%. After the electromagnetic compound treatment, the pulse current provided the driving force for dislocation motion. A strong pulse current driving force is more likely to make the dislocation multiply and slip. A high density dislocation cell is formed within the material, so the mechanical properties were significantly increased. 展开更多
关键词 CemENTED CARBIDE magnetic field TREATMENT electromagnetic COMPOUND TREATMENT microstructure/performance
原文传递
EMS型中低速磁浮列车悬浮架技术研究综述 被引量:8
7
作者 马卫华 胡俊雄 +2 位作者 李铁 罗世辉 刘树洪 《西南交通大学学报》 EI CSCD 北大核心 2023年第4期720-733,共14页
悬浮架是承载EMS(electro-magnetic suspension)型中低速磁浮列车运行的关键子系统,影响列车的悬浮稳定性、舒适性和安全性,需要对其进行深入研究.围绕国内外EMS型中低速磁浮列车应用案例,介绍了(悬挂)端置式悬浮架、(悬挂)中置式悬浮... 悬浮架是承载EMS(electro-magnetic suspension)型中低速磁浮列车运行的关键子系统,影响列车的悬浮稳定性、舒适性和安全性,需要对其进行深入研究.围绕国内外EMS型中低速磁浮列车应用案例,介绍了(悬挂)端置式悬浮架、(悬挂)中置式悬浮架的技术方案和特征,总结了主要技术指标.结合悬浮架技术研究、发展现状,讨论了磁轨作用关系、运动解耦能力、动力学性能、结构强度以及悬浮冗余设计五大研究方向,通过对研究内容梳理和总结,归纳了现有前沿科学问题和工程技术挑战:一是轨距亟须统一;二是动态磁轨关系研究欠缺;三是悬浮架横向动力学有待研究;四是悬浮架疲劳强度分析及试验不足;五是悬浮架机械结构冗余设计方案较少. 展开更多
关键词 电磁悬浮(emS) 中低速磁浮列车 悬浮架 发展动态
下载PDF
Spatio-Temporal Changes of Soil Salinity in Arid Areas of South Xinjiang Using Electromagnetic Induction 被引量:10
8
作者 LI Xiao-ming YANG Jing-song +2 位作者 LIU Mei-xian LIU Guang-ming YU Mei 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第8期1365-1376,共12页
The aim of this paper was to research the spatio-temporal changes in total soluble salt content (TS) in a typical arid region of South Xinjiang, China, where the climate is arid and soil salinization happens easily.... The aim of this paper was to research the spatio-temporal changes in total soluble salt content (TS) in a typical arid region of South Xinjiang, China, where the climate is arid and soil salinization happens easily. The total soluble salt content was interpreted by measurements made in the horizontal mode with EM38 and EM31. The electromagnetic induction (EM) surveys were made three times with the apparent soil electrical conductivity (ECa) measurements taken at 3 873 locations in Nov. 2008, 4 807 locations in Apr. 2009 and 6 324 locations in Nov. 2009, respectively. For interpreting the ECa measurements into total soluble salt content, calibtion sites were needed for EM survey of each time, e.g., 66 sites were selected in Nov. 2008 to measure ECa, and soils-core samples were taken by different depth layers of 0-10, 10-20 and 20-40 cm at the same time. On every time duplicate samples were taken at five sites to allevaite the local-scale variability, and soil temperatures in different layers through the profiles were also measured. Factors including TS, pH, water content, bulk density were analyzed by lab experiments. ECa calibration equations were obtained by linear regression analysis, which indicated that soil salinity was one primary concern to ECa with a determination coefficient of 0.792 in 0-10 cm layer, 0.711 in 10-20 cm layer and 0.544 in 20-40 cm layer, respectively. The maps of spatial distribution were predicted by Kriging interpolation, which showed that the high soil salinity was located near the drainage canal, which validated the trend effect caused by the irrigation canal and the drainage canal. And by comparing the soil salinity in different layers, the soluble salt accumulated to the top soil surface only in the area where the soil salinization was serious, and in the other areas, the soil salinity trended to increase from the top soil surface to 40 cm depth. Temporal changes showed that the soil salinity in November was higher than that in April, and the soil salinization trended to aggravate, especially in the top soil layer of 0-10 cm. 展开更多
关键词 spatio-temporal changes soil salinity South Xinjiang electromagnetic induction em KRIGING
下载PDF
Study of electromagnetic and acoustic emission in creep experiments of water-containing rock samples 被引量:7
9
作者 JING Hong-wen ZHANG Zhong-yu XU Guo-an 《Journal of China University of Mining and Technology》 EI 2008年第1期42-45,共4页
Based on biaxial shear creep tests conducted on rock samples with different water contents, we present the results of our study on the regularities of electromagnetic and acoustic emission during the process of creep ... Based on biaxial shear creep tests conducted on rock samples with different water contents, we present the results of our study on the regularities of electromagnetic and acoustic emission during the process of creep experiments in which we have analyzed the contribution of water to the occurrence of electromagnetic radiation. The result shows that in the creep-fracturing course of rock samples, when the water content increases, the initial frequency and amplitude of electromagnetic and acoustic emission also increases, but at a decreasing growth rate caused by loading stress. This can be used as a criterion for the long-term stability of rock masses under conditions of repeated inundation and discharge of water. 展开更多
关键词 electromagnetic emission emE) acoustic emission (AE) biaxial shear creep tests water content
下载PDF
Numerical Method for Solving Electromagnetic Scattering Problem by Many Small Impedance Bodies 被引量:3
10
作者 Nhan T. Tran 《American Journal of Computational Mathematics》 2017年第4期435-443,共9页
In this paper, we study electromagnetic (EM) wave scattering problem by many small impedance bodies. A numerical method for solving this problem is presented. The problem is solved under the physical assumptions ka??1... In this paper, we study electromagnetic (EM) wave scattering problem by many small impedance bodies. A numerical method for solving this problem is presented. The problem is solved under the physical assumptions ka??1, where a is the characteristic size of the bodies and k is the wave number. This problem is solved asymptotically and numerical experiments are provided to illustrate the idea of the method. Error estimate for the asymptotic solution is also discussed. 展开更多
关键词 electromagnetic SCATTERING Integral Equation Boundary IMPEDANCE MANY-BODY SCATTERING em Waves
下载PDF
Guided and Direct Wave Evaluation of Controlled Source Electromagnetic Survey Using Finite Element Method 被引量:1
11
作者 Noorhana Yahya Majid Niaz Akhtar +3 位作者 Nadeem Nasir Muhammad Kashif Afza Shafie Hasnah Mohd Zaid 《Journal of Electromagnetic Analysis and Applications》 2012年第3期135-146,共12页
Deep target hydrocarbon detection is still challenging and expensive. Direct hydrocarbon indicators (DHIs) in seismic data do not correspond to economical hydrocarbon exploration. Due to unreliability in seismic data ... Deep target hydrocarbon detection is still challenging and expensive. Direct hydrocarbon indicators (DHIs) in seismic data do not correspond to economical hydrocarbon exploration. Due to unreliability in seismic data for the detection of DHIs, new methods have been investigated. Marine controlled source electromagnet (MCSEM) or Sea bed logging (SBL) is new method for the detection of deep target hydrocarbon reservoir. Sea bed logging has also the potential to reduce the risks of DHIs in deep sea environment. Modelling of real sea environment helps to reduce the further risks before drilling the oil wells. 3D electromagnetic (EM) modelling of seabed logging requires more accurate methods for the detection of hydrocarbon reservoir. Finite element method (FEM) is chosen for the modelling of seabed logging to get more precise EM response from hydrocarbon reservoir below 4000 m from seabed. FEM allows to investigate the total electric and magnetic fields instead of scattered electric and magnetic fields, which shows accurate and precise resistivity contrast below the seabed. From the modelling results, It was investigated that Hz field shows higher magni- tude with 342% than the Ex field. It was observed that 0.125 Hz frequency can be able to show better resistivity contrast of Hz field (31.30%) and Ex field (16.49%) at target depth of 1000 m below seafloor for our proposed model. Hz and Ex field delineation was found to decrease as target depth increased from 1000 m to 4000 m. At the target depth of 4000 m, no field delineation response was seen from the current electromagnetic (EM) antenna used by the industry. New EM antenna has been used to see the EM response for deep target hydrocarbon detection. It was investigated that novel EM antenna shows better delineation at 4000 m target depth for Ex and Hz field up to 10.3% and 15.1% respectively. Novel EM antenna also shows better Hz phase response (128.4%) than the Ex phase response (38.3%) at the target depth of 4000 m below the seafloor. 展开更多
关键词 SEA BED LOGGING Controlled Source electromagnetic (CSem) electromagnetic (em) Antenna and Finite Element Method
下载PDF
Semisolid slurry of 7A04 aluminum alloy prepared by electromagnetic stirring and Sc, Zr additions 被引量:2
12
作者 Jun-wen Zhao An Guo +3 位作者 Hu Li Xu Zhang Jing Han Shu-sen Wu 《China Foundry》 SCIE 2017年第3期188-193,共6页
Slurry preparation is one of the most critical steps for semisolid casting, and its primary goal is to prepare slurry with uniformly distributed fine globules. In this work, electromagnetic stirring(EMS) and the addit... Slurry preparation is one of the most critical steps for semisolid casting, and its primary goal is to prepare slurry with uniformly distributed fine globules. In this work, electromagnetic stirring(EMS) and the addition of Sc and Zr elements were used to prepare semisolid slurry of 7A04 aluminum alloy in a large diameter slurry maker. The effects of different treatments on the microstructure, composition and their radial homogeneity were investigated. The results show that, compared to the slurry without any treatment, large volume slurry with finer and more uniform microstructure can be obtained when treated by EMS, Sc, or Zr additions individually. EMS is more competent in the microstructural and chemical homogenization of the slurry while Sc and Zr additions are more excellent in its microstructural refinement. The combined treatment of EMS, Sc and Zr produces premium 7A04 aluminum alloy slurry with uniformly distributed fine α-Al globules and composition. The interaction mechanism between EMS and Sc and Zr additions was also discussed. 展开更多
关键词 aluminum alloy Zr and Sc additions semisolid slurry electromagnetic stirring(emS) homogeneity
下载PDF
Progress of Expert Systems in Electromagnetic Engineering 被引量:1
13
作者 赖生建 王秉中 《Journal of Electronic Science and Technology of China》 2005年第4期328-333,共6页
It is urgent to solve various problems in electromagnetic (EM) engineering under the increasingly complicated environment. Some expert systems (ES) come into being just to keep up with the demand for solving these... It is urgent to solve various problems in electromagnetic (EM) engineering under the increasingly complicated environment. Some expert systems (ES) come into being just to keep up with the demand for solving these problems. Combined with the analysis of development orES technology and the development trend of EM engineering software in recent years, the application orES technology in EM engineering is discussed, and especially the progress of complete ES in electromagnetic compatible (EMC) is introduced. 展开更多
关键词 electromagnetic em engineering expert system KNOWLEDGE-BASE engineering software electromagnetic compatible emC) electromagnetic interfere(emI)
下载PDF
Lubricating Performance of Rapeseed Oil Under Electromagnetic Field
14
作者 Jiang Zeqi Liu Ping +3 位作者 Fang Jianhua Chen Boshui Gu Kecheng Wu Jiang 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2018年第1期85-92,共8页
Considering electromagnetic effect when investigating tribological properties of rapeseed oil is benefical not only to the improvement of green lubrication, but also to the development of tribology theories and practi... Considering electromagnetic effect when investigating tribological properties of rapeseed oil is benefical not only to the improvement of green lubrication, but also to the development of tribology theories and practices. In the present paper, the tribological properties of rapeseed oil under different intensity of electromagnetic field and normal loads were evaluated on a modified tribo-tester. The results indicated that the electromagnetic field could improve the anti-wear and friction-reducing property of the rapeseed oil. Furthermore, the influencing mechanisms were discussed from the perspective of electromagnetism according to the analytical results of SEM, EDS and XPS techniques. 展开更多
关键词 RAPESEED oil electromagnetic field ANTI-WEAR PROPERTY FRICTION-REDUCING performance
下载PDF
A nonlinear control method for the electromagnetic suspension system of the maglev train
15
作者 Junqi XU Yuan ZHOU 《Journal of Modern Transportation》 2011年第3期176-180,共5页
To deal with the inherent nonlinearity and open-loop instability of the electromagnetic suspension(EMS) system,a new nonlinear control method is proposed.The simulation results show that,for a PID controller,the ove... To deal with the inherent nonlinearity and open-loop instability of the electromagnetic suspension(EMS) system,a new nonlinear control method is proposed.The simulation results show that,for a PID controller,the over-shoot of the system response to an airgap step disturbance is about 3 mm,and the transient time is 6 s;however,for the proposed nonlinear controller,there is no overshoot and transient time within 2 s.The proposed method has a faster response and stronger robustness.With a designed bi-DSP suspension controller,this nonlinear control method was implemented on the Shanghai Urban Maglev Test Line(SUMTL) to validate its effectiveness and feasibility. 展开更多
关键词 nonlinear control electromagnetic suspension(emS) maglev train DSP
下载PDF
Dynamic performance of linear electromagnetic actuators in a stray magnetic field:theoretical analysis and experimental verification
16
作者 Rumeng WANG Yong YANG +1 位作者 Shaoyu WANG Ming ZHANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第12期213-222,共10页
Linear electromagnetic actuators(LEAs) are widely used in tokamaks,but they are extremely sensitive to and are prone to fail in a high-strength stray magnetic field(SMF),which is usually a concomitant with tokamaks.In... Linear electromagnetic actuators(LEAs) are widely used in tokamaks,but they are extremely sensitive to and are prone to fail in a high-strength stray magnetic field(SMF),which is usually a concomitant with tokamaks.In this paper,a multi-physics coupling analysis model of LEA,including magnetic field,electric circuit and mechanical motion,is proposed,and the dynamic characteristics of LEAs in SMFs are studied in detail based on the proposed model.The failure mechanism of LEAs in SMFs is revealed,and the influence of SMFs on the dynamic performance of LEAs is studied and quantified.It is shown that the failure threshold of the LEA selected in this work under the rated condition is 27 mT and 14 mT in the positive and negative direction,respectively.Under a typical SMF of 10 mT in the negative direction,the closing time of the LEA will be extended by 40%,while its opening time will be shortened by about 10%.Experimental tests are also conducted,which verify the validity of the proposed model and the analysis results.This paper provides a basis for the diamagnetic optimization design of LEA,and it is of great significance to ensure the reliable operation of the tokamak. 展开更多
关键词 linear electromagnetic actuator stray magnetic field dynamic performance collision velocity
下载PDF
EMS型磁浮列车悬浮静磁场电磁环境仿真研究 被引量:3
17
作者 潘强强 逯迈 《中国铁道科学》 EI CAS CSCD 北大核心 2023年第2期102-110,共9页
为量化评估常导电磁悬浮(EMS)型磁浮列车的电磁环境风险,在确定位于磁浮列车悬浮架两侧的直线电机转子励磁线圈为辐射源的基础上,采用有限元软件COMSOL Multiphysics,建立长定子轨道和EMS型磁浮列车三维结构模型,对直线电机的悬浮电磁... 为量化评估常导电磁悬浮(EMS)型磁浮列车的电磁环境风险,在确定位于磁浮列车悬浮架两侧的直线电机转子励磁线圈为辐射源的基础上,采用有限元软件COMSOL Multiphysics,建立长定子轨道和EMS型磁浮列车三维结构模型,对直线电机的悬浮电磁特性以及它在周围空间和磁浮列车车厢内产生的静磁场进行仿真计算,并将车厢内的磁通密度计算结果与静磁场暴露限值标准进行对比。结果表明:长定子直线电机在励磁电流为25 A时,悬浮间隙中心线处磁通密度最大模值约为0.9 T,悬浮电磁力约为19.7 kN·m^(-1);磁浮列车夹层位置处磁通密度最大模值在9.39~53.6 uT范围内,车厢内磁通密度最大模值约为6.93 uT;悬浮励磁线圈在车厢内产生的磁通密度最大值远低于国际非电离辐射防护委员会(ICNIRP)对一般公众推荐的400 mT静磁暴露限值,且满足标准EN 45502-2-1—2003和GB 16174.2—2015中小于1 mT的静磁场暴露控制限值。 展开更多
关键词 emS型磁浮列车 直线电机 静磁场 电磁环境 暴露控制标准
下载PDF
Deep learning-based method for detecting anomalies in electromagnetic environment situation
18
作者 Wei-lin Hu Lun-wen Wang +2 位作者 Chuang Peng Ran-gang Zhu Meng-bo Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第8期231-241,共11页
The anomaly detection of electromagnetic environment situation(EMES) has essential reference value for electromagnetic equipment behavior cognition and battlefield threat assessment.In this paper,we proposed a deep le... The anomaly detection of electromagnetic environment situation(EMES) has essential reference value for electromagnetic equipment behavior cognition and battlefield threat assessment.In this paper,we proposed a deep learning-based method for detecting anomalies in EMES to address the problem of relatively low efficiency of electromagnetic environment situation anomaly detection(EMES-AD).Firstly,the convolutional kernel extracts the static features of different regions of the EMES.Secondly,the dynamic features of the region are obtained by using a recurrent neural network(LSTM).Thirdly,the Spatio-temporal features of the region are recovered by using a de-convolutional network and then fused to predict the EMES.The structural similarity algorithm(SSIM) is used to determine whether it is anomalous.We developed the detection framework,de-signed the network parameters,simulated the data sets containing different anomalous types of EMES,and carried out the detection experiments.The experimental results show that the proposed method is effective. 展开更多
关键词 electromagnetic environment situation(emES) Anomaly detection(AD) Regional features integration LSTM CNN
下载PDF
Yang-Mills Mass Gap Problem: A Possible Solution
19
作者 Antonio Puccini 《Journal of Applied Mathematics and Physics》 2023年第6期1755-1794,共40页
As known, the spontaneous symmetry breaking (SSB) and the Brout-Englert-Higgs Mechanism (BEH-M) solved the Yang-Mills Mass Gap Problem. However, various mathematicians, even prestigious ones, consider the basic assump... As known, the spontaneous symmetry breaking (SSB) and the Brout-Englert-Higgs Mechanism (BEH-M) solved the Yang-Mills Mass Gap Problem. However, various mathematicians, even prestigious ones, consider the basic assumptions of the gauge theories to be wrong, as well as in conflict with the experimental evidence and in clear disagreement with the facts, distorting the physical reality itself. Likewise, these theories are mathematically inconsistent, adopting a mathematical structure somewhat complicated and arbitrary, which does not satisfy the strong demands for coherence. The weakest point of the gauge theories, in our opinion, consists in imposing that all the particles must be free of an intrinsic mass. On the contrary, even for the particle considered universally massless, i.e. the photon, our calculations show a dynamic-mass, a push-momentum (p) of 1.325 × 10<sup>-22</sup> [g⋅cm/s]. With this work we try to provide a possible solution to the Yang-Mills Mass Gap Problem, but without taking into account the SSB, nor using the BEH-M. We try to provide a mathematical explanation for this phenomenon, considering that in the spectrum of the Yang-Mills theory, there is a mass gap, that is, the difference between the energy of the vacuum state and the first excited state is different from zero. In other words, the lightest of the particles predicted by the theory must have a strictly positive mass to explain the short range of strong nuclear forces. It is clear, indeed, that if we replaced this value with the null value of the photon inserted in the equations of the Perturbation Theory, the Quantum Fields Theory and the Yang-Mills theories, all divergences, that is all zeroes and infinities, would suddenly disappear. Consequently, the limits imposed by the SSB disappear so that there is no longer any need to deny the mass to the Nuclear Forces bosons, including the Yang-Mills b quantum. 展开更多
关键词 electromagnetic (em) Quantum Fields Theory (QFT) Spontaneous Symmetry Breaking (SSB) Gluon (G) Photon (P)
下载PDF
身管外壳对电磁轨道发射装置发射性能影响分析 被引量:1
20
作者 翟小飞 邹锟 +2 位作者 李配飞 刘华 彭之然 《电工技术学报》 EI CSCD 北大核心 2024年第2期333-342,共10页
电枢在发射过程中,瞬时变化的导轨电流会在金属身管外壳上感应出巨大的涡流,身管涡流会产生额外的损耗,同时外壳涡流的去磁效应会改变电枢、导轨等器部件的应力分布从而影响装置发射性能。该文建立了电磁轨道发射装置的数学模型,并针对... 电枢在发射过程中,瞬时变化的导轨电流会在金属身管外壳上感应出巨大的涡流,身管涡流会产生额外的损耗,同时外壳涡流的去磁效应会改变电枢、导轨等器部件的应力分布从而影响装置发射性能。该文建立了电磁轨道发射装置的数学模型,并针对整体式、上下分断式以及叠压式三种外壳结构有限元模型进行了电磁场-结构场联合仿真,获得了发射装置电磁参数和各部件应力分布。有限元电磁仿真结果表明,叠压式外壳结构外壳涡流最小、电感梯度最大、器部件应力最大,整体式外壳结构外壳涡流最大、电感梯度最小、器部件应力最小。全系统电气仿真和对比试验证明,在满足外壳支持强度和装置各部件应力条件下,选用高磁导率、低电导率的材料并设计抑制涡流的身管外壳结构,有利于提高发射装置电枢出口速度和系统效率,从而获得优良的发射性能。 展开更多
关键词 电磁轨道发射装置 外壳结构 发射性能 电流密度分布 应力分布
下载PDF
上一页 1 2 51 下一页 到第
使用帮助 返回顶部