The first laboratory of electromagnetic compatibility in Chinais possessed of vivid characteristics in respect of design and configurationof testing equipment. It has successively completed some testing projectsand wi...The first laboratory of electromagnetic compatibility in Chinais possessed of vivid characteristics in respect of design and configurationof testing equipment. It has successively completed some testing projectsand will unfold a more extensive range of measurement and test works inthe days to come.[展开更多
The electromagnetic compatibility of electric vehicles is not only the important technology issue in researches,development and industrialization of electric vehicles,but also the key research area of ISO.In this pape...The electromagnetic compatibility of electric vehicles is not only the important technology issue in researches,development and industrialization of electric vehicles,but also the key research area of ISO.In this paper,both national and international standards of electromagnetic compatibility of electric vehicles are analyzed;it is also suggested that our standards of electromagnetic compatibility of electric vehicles be improved from several aspects such as testing items,test procedures,limit value,etc.The electromagnetic environment of electric vehicles is analyzed in terms of interfering sources,providing the solutions to electromagnetic compatibility and measures of reducing electromagnetic interference.Advanced equipments introduced into Chinese electromagnetic compatibility testing laboratories accelerate the pace of the researches on related technologies and standards;China will develop the standards system which covers from the complete electric vehicle to the key components,promote the technology improvement and industrialization work of Chinese electric vehicles,transform the latest achievements and advanced experiences of Chinese electric vehicles industry to the related standards and contribute the development of international standards.展开更多
The group of Electrical Engineering and Electromagnetic Compatibility undertakes the design of AC power distribution system along with electromagnetic compatibility and integrated wiring in Heavy-ion Accelerator Facil...The group of Electrical Engineering and Electromagnetic Compatibility undertakes the design of AC power distribution system along with electromagnetic compatibility and integrated wiring in Heavy-ion Accelerator Facilities.展开更多
The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled compo...The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled components.However,the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency.Herein,we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications.The as-printed frames are reinforced by immersing in AlCl_(3)/HCl solution to remove the electrically insulating AlOOH nanoparticles,as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions.After freeze-drying,the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25-80 dB with the highest electrical conductivity of 5323 S m−1.Furthermore,an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern,and its color can be changed from blue to red under the high-intensity electromagnetic irradiation.This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.展开更多
Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shieldin...Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shielding materials(i.e.,when the EM wave is incident from different sides of the sample,the EMI shielding effectiveness(SE)is rather different)are strongly required;unfortunately,no comprehensive literature report is available on this research field.Herein,Nicoated melamine foams(Ni@MF)were obtained by a facile electroless plating process,and multiwalled carbon nanotube(CNT)papers were prepared via a simple vacuum-assisted self-assembly approach.Then,step-wise asymmetric poly(butylene adipate-co-terephthalate)(PBAT)composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation approach.The step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding performances.When the EM wave is incident from Ni@MF layer or CNT layer,Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE(SET)of 38.3 and 29.5 dB,respectively,which illustrates theΔSET of 8.8 dB.This work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures,which has promising applications in portable electronics and next-generation communication technologies.展开更多
Aiming at the complex electromagnetic transient process of EMU passing by phase-separation with electric load in high-speed railway, mechanism of overvoltage caused by switching off, overvoltage caused by switching on...Aiming at the complex electromagnetic transient process of EMU passing by phase-separation with electric load in high-speed railway, mechanism of overvoltage caused by switching off, overvoltage caused by switching on and impact current is analyzed systematically in this article. π-type equivalent circuit of feeding section is put forward in the analysis of overvoltage mechanism. Overvoltage and overcurrent model of passing by phase-separation with electric load are also built. Correctness of mechanism was validated by simulation. In addition, the methods to solve the influence on substations, transformers and protection devices in this process are put forward, which provides a new idea on passing by phase-separation with electric load technology.展开更多
To reduce the environmental pollution and meet the needs for wearable electronic devices, new requirements for electromagnetic interference(EMI) shielding materials include flexibility, biodegradability, and biocompat...To reduce the environmental pollution and meet the needs for wearable electronic devices, new requirements for electromagnetic interference(EMI) shielding materials include flexibility, biodegradability, and biocompatibility. Herein, we reported a polypyrrole-coated zein/epoxy(PPy/ZE) ultrafine fiber mat which was inherently biodegradable and skin-friendly. In addition, it could maintain its ultrafine fibrous structure after coating, which could provide the mat with mechanical compliance, high porosity, and a large specific area for high EMI shielding. With the assistance of the epoxide cross-linking, the breaking stresses of the PPy/ZE fiber mats could achieve 3.3 MPa and 1.4 MPa and the strains were 40.1% and 83.0% in dry and wet states, respectively, which met the needs of various wearable electronic devices. Along with the extension in the PPy treatment duration, more PPy was loaded on the fiber surfaces, which formed more integrated and conductive paths to generate increasing conductivities up to 401.76 S·m^(-1). Moreover, the EMI shielding performance was raised to 26.84 dB. The biobased mats provide a green and efficient choice for EMI shielding materials, which may be a promising strategy to address EMI problems in multiple fields.展开更多
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
As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and pr...As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.展开更多
This paper presents a study on the effects of radiation from electronic equipment in hospitals. This study was performed in Argentinean, Colombian and Spanish hospitals. The work consists of two parts: a survey to det...This paper presents a study on the effects of radiation from electronic equipment in hospitals. This study was performed in Argentinean, Colombian and Spanish hospitals. The work consists of two parts: a survey to determine the hospital personnel’s knowledge of the problem and a technical part consisting of a measurements campaign to determine the levels of radiated electrical and magnetic fields in several hospitals due to the presence of electromagnetic interferences, such as the use of mobile phones. The study of this problem has been of special interest in countries such as the USA and Canada, and this paper attempts to convey the necessity of creating regulations that can be applied to the hospitals of the countries analyzed. More than fifty hospitals were studied in these three countries, considering the following aspects: the hospital personnel’s awareness of the problem, whether the hospitals have performed previous studies of this type, the appearance of problems in medical equipment due to this interference, the origin of the interference, and the failures that have appeared in computers due to electromagnetic interference. The results show that, most hospitals have a lack of knowledge regarding this issue and that field levels above those allowed by international regulations are present. Therefore, a regulation must be established to avoid the problem.展开更多
As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagno...As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagnoses the essential interaction relationship between interference and switching activity based on the timely and area measured waveform,analyzes and studies the production mechanism and coupling path of interference mode,and sets up circuit model according to the features of transverse mode interference and common mode interference.Put forward different suppression methods finally.展开更多
To design a power source system and mold for electromagnetic soft-contact continuous casting process and to theoretically estimate the heat losses from the charges and the system power, the effect of structure paramet...To design a power source system and mold for electromagnetic soft-contact continuous casting process and to theoretically estimate the heat losses from the charges and the system power, the effect of structure parameters on system power and magnetic flux density distribution was calculated using finite element method. The results show that as for electromagnetic soft-contact continuous casting system with partial-segment type mold, the power consumption is much more than that with a full-segment type mold; about 62% of electric power is dissipated in the mold, and the effective acting range of magnetic field is relatively narrow. Optimizing mold structure is a crucial measure of remarkably reducing mold power consumption and saving electric energy. Increasing slit number, width, and length can remarkably increase the magnetic flux density in the mold and can reduce the electric energy consumption. Among structure parameters, slit number and slit width are relatively more effective to reduce energy consumption. For a round billet electromagnetic continuous casting system with diameter of 178 ram, the reasonable slit number, width, and length are about 24--32, 0. 5--1.0 mm, and 160 mm, respectively.展开更多
A systematic approach to the design of the conducted electromagnetic interference (EMI) filter of high-density plasma cutting power supply has been developed. Converter components have been accurately modeled, with ...A systematic approach to the design of the conducted electromagnetic interference (EMI) filter of high-density plasma cutting power supply has been developed. Converter components have been accurately modeled, with parasitic elements extracted to reveal their impacts on the EMI noises. Circuit simulations have been used to analyze and minimize the EMI noises. Conducted EMI noise measurement and filter design of this power supply have been achieved which successfully satisfy the FCC class B limits in the frequency range from 150 kHz to 30 MHz. The analyses and experimental results show that the designed filter guarantees that the required attenuation will be achieved.展开更多
The surface modification on the AA6082 Al?Mg?Si aging-hardenable aluminum alloy was investigated by electricaldischarge alloying (EDA) process. Kerosene, used as a dielectric fluid, was pyrolytically decomposed into c...The surface modification on the AA6082 Al?Mg?Si aging-hardenable aluminum alloy was investigated by electricaldischarge alloying (EDA) process. Kerosene, used as a dielectric fluid, was pyrolytically decomposed into carbon for the formationof a self-lubricated carbide layer on the aluminum alloy surface during EDA process. Transmission electron microscopy (TEM)image found that the self-lubricated carbide layer was a multi-phase material with carbides and graphite. As a result, theEDA-modified aluminum alloy had a negligible wear rate of ~2?10?4 mg/m (c. f. ~1.1?10?2 mg/m for aluminum alloy substrate).Notably, a new characteristic was found that the EDA-processed carbide layer was a soft magnet, which improved theelectromagnetic interference (EMI) shielding performance of the alloy.展开更多
The trajectory related and Direct Current(DC)Electromagnetic Interference(EMI)of lithium battery,fuel cell and photovoltaic modules has a great influence on the small-scale Unmanned Aerial Vehicle(UAV)airborne magneto...The trajectory related and Direct Current(DC)Electromagnetic Interference(EMI)of lithium battery,fuel cell and photovoltaic modules has a great influence on the small-scale Unmanned Aerial Vehicle(UAV)airborne magnetometer and is hard to be shielded,calibrated or filtered.Besides,the mechanisms underlying the DC EMI have been rarely investigated yet.To cope with this problem,this paper systematically studies the EMI models,and proposes an online 3-layer EMI reduction scheme.First,EMI coupled with UAV motion model and hybrid power system is established.Second,the mechanism EMI models of hybrid power system are established and verified based on the proposed concept“equivalent current”.Third,an online 3-layer EMI reduction scheme is proposed,including battery layer,trajectory planning layer and energy management layer.In the first main layer,EMI self-cancellation is realized by rotating battery inclinations and symmetrical circuits.In response to errors,the trajectory planning layer reduces the EMI intensity by optimizing an optimal trajectory,while the energy management layer prioritizes power allocation to power sources that can produce small and stable EMI.Simulation results of climb,level flight and descent illustrate the efficaciousness and applicability of the proposed online 3-layer EMI reduction scheme.展开更多
BACKGROUND Electromagnetic interference(EMI),means disturbance to the operation of implanted electrical devices caused by external sources.If cardiac pacemaker is implanted into the body,the risk of EMI should be cons...BACKGROUND Electromagnetic interference(EMI),means disturbance to the operation of implanted electrical devices caused by external sources.If cardiac pacemaker is implanted into the body,the risk of EMI should be considered when performing neuromuscular electrical stimulation(NMES).So far,no case has been reported that clinical magnets are used to safely manage the EMI risk of patients with cardiac pacemaker in NMES.CASE SUMMARY A 72-year-old male with swallowing disorder due to pure motor lacunar syndrome was transferred to rehabilitation department six days after the symptom onset.EMI risk needed be considered when implementing NMES on pharyngeal muscles,since cardiac pacemaker was implanted on his left chest due to the sick sinus syndrome.In the first NMES,the function of the pacemaker was directly monitored using telemetric instruments.From the second day,by a simple method of placing a magnet on the pacemaker,we chose to move the pacemaker into a mode that the device was not influenced by external stimulus.This magnet method has been used repeatedly for a year for the safe NMES treatment.We could remove Levin tube four months after the initial symptom and dysphagia related symptoms had not been noted during two-year follow-up period.CONCLUSION This report is the first case of dysphagia rehabilitation that EMI risk was handled using mode change of pacemaker with magnet.This method is unfamiliar to doctors,but safe and easy approach.This paper could be guidance for clinicians who need to treat patients with EMI risk.展开更多
To investigate electromagnetic interference (EMI) of electromagnetic fields (EMF) from electronic article surveillance (EAS) systems with electronic implants numerical anatomical models of pacemaker patients were gene...To investigate electromagnetic interference (EMI) of electromagnetic fields (EMF) from electronic article surveillance (EAS) systems with electronic implants numerical anatomical models of pacemaker patients were generated accounting for different implantation sites (left pectoral, right pectoral and abdominal) and body size. Induced interference voltages were calculated with a software package applying the Finite Integration Technique and analysed in dependence on frequency. Results were referred to reported maximum magnetic fields levels measured at EAS systems in the ELF, IF and RF range. With reference to electromagnetic immunity requirements of safety standards of implanted cardiac pacemakers and defibrillators, the numerical analysis showed that the relevance of interference depends on the applied EMF frequency. At EAS systems operating in the RF range, EMI and consequential inadequate pacing is rare but cannot be ruled out. The probability of such events increases at EAS systems in the IF range and even more in the ELF range. Since interference is encountered already at yet existing systems, the situation would be worse if future systems would further increase their emissions by making use of the elevated reference levels recommended in updated exposure guidelines.展开更多
In order to solve the failure of electricity anti-stealing detection device triggered by the noise mixed in high-frequency electricity stealing signals,a denoising method based on variational mode decomposition(VMD)an...In order to solve the failure of electricity anti-stealing detection device triggered by the noise mixed in high-frequency electricity stealing signals,a denoising method based on variational mode decomposition(VMD)and wavelet threshold denoising(WTD)was applied to extract the effective high-frequency electricity stealing signals.First,the signal polluted by noise was pre-decomposed using the VMD algorithm,the instantaneous frequency means of each pre-decomposed components was analyzed,so as to determine the optimal K value.The optimal K value was used to decompose the polluted signal into K intrinsic mode components,and the sensitive mode components were determined through the cross-correlation function.Next,each sensitive mode was reconstructed.Finally,the reconstructed signal denoised using the wavelet threshold to obtain the denoised signal.The simulation analysis and experimental results show that the proposed method is superior to the traditional VMD method,FFT method and EMD method,as it can effectively eliminate the noise and enhance the reliability of high-frequency electricity stealing signal detection.展开更多
文摘The first laboratory of electromagnetic compatibility in Chinais possessed of vivid characteristics in respect of design and configurationof testing equipment. It has successively completed some testing projectsand will unfold a more extensive range of measurement and test works inthe days to come.[
文摘The electromagnetic compatibility of electric vehicles is not only the important technology issue in researches,development and industrialization of electric vehicles,but also the key research area of ISO.In this paper,both national and international standards of electromagnetic compatibility of electric vehicles are analyzed;it is also suggested that our standards of electromagnetic compatibility of electric vehicles be improved from several aspects such as testing items,test procedures,limit value,etc.The electromagnetic environment of electric vehicles is analyzed in terms of interfering sources,providing the solutions to electromagnetic compatibility and measures of reducing electromagnetic interference.Advanced equipments introduced into Chinese electromagnetic compatibility testing laboratories accelerate the pace of the researches on related technologies and standards;China will develop the standards system which covers from the complete electric vehicle to the key components,promote the technology improvement and industrialization work of Chinese electric vehicles,transform the latest achievements and advanced experiences of Chinese electric vehicles industry to the related standards and contribute the development of international standards.
文摘The group of Electrical Engineering and Electromagnetic Compatibility undertakes the design of AC power distribution system along with electromagnetic compatibility and integrated wiring in Heavy-ion Accelerator Facilities.
基金support from the National Natural Science Foundation of China(51922020,52090034)the Fundamental Research Funds for the Central Universities(BHYC1707B)。
文摘The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled components.However,the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency.Herein,we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications.The as-printed frames are reinforced by immersing in AlCl_(3)/HCl solution to remove the electrically insulating AlOOH nanoparticles,as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions.After freeze-drying,the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25-80 dB with the highest electrical conductivity of 5323 S m−1.Furthermore,an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern,and its color can be changed from blue to red under the high-intensity electromagnetic irradiation.This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.
基金Science and Technology Plan Project of Guizhou Province(No.[2019]1084 and[2018]5781)National Natural Science Foundation of China(No.51963003)+3 种基金The Youth Science and Technology Talent Growth Project of Guizhou Province Education Department(No.[2018]106)Outstanding Youth Program of Guizhou Province(No.20170439178)The Key project of Fundamental research in Guizhou province[2020]1Z044Scientific Research Project of Introduced Talents of Guizhou University(No.(2017)07)are acknowledged for the financial support.
文摘Some precision electronics such as signal transmitters need to not only emit effective signal but also be protected from the external electromagnetic(EM)waves.Thus,directional electromagnetic interference(EMI)shielding materials(i.e.,when the EM wave is incident from different sides of the sample,the EMI shielding effectiveness(SE)is rather different)are strongly required;unfortunately,no comprehensive literature report is available on this research field.Herein,Nicoated melamine foams(Ni@MF)were obtained by a facile electroless plating process,and multiwalled carbon nanotube(CNT)papers were prepared via a simple vacuum-assisted self-assembly approach.Then,step-wise asymmetric poly(butylene adipate-co-terephthalate)(PBAT)composites consisting of loose Ni@MF layer and compact CNT layer were successfully fabricated via a facile solution encapsulation approach.The step-wise asymmetric structures and electrical conductivity endow the Ni@MF/CNT/PBAT composites with unprecedented directional EMI shielding performances.When the EM wave is incident from Ni@MF layer or CNT layer,Ni@MF-5/CNT-75/PBAT exhibits the total EMI SE(SET)of 38.3 and 29.5 dB,respectively,which illustrates theΔSET of 8.8 dB.This work opens a new research window for directional EMI shielding composites with step-wise asymmetric structures,which has promising applications in portable electronics and next-generation communication technologies.
文摘Aiming at the complex electromagnetic transient process of EMU passing by phase-separation with electric load in high-speed railway, mechanism of overvoltage caused by switching off, overvoltage caused by switching on and impact current is analyzed systematically in this article. π-type equivalent circuit of feeding section is put forward in the analysis of overvoltage mechanism. Overvoltage and overcurrent model of passing by phase-separation with electric load are also built. Correctness of mechanism was validated by simulation. In addition, the methods to solve the influence on substations, transformers and protection devices in this process are put forward, which provides a new idea on passing by phase-separation with electric load technology.
基金Fundamental Research Funds for the Central Universities,China(No. 2232022D-13)Fundamental Research Funds of Shanghai Collaborative Innovation Center of High Performance Fibers and Composites (Province-M inistry Joint),China(No. X12812101/015)。
文摘To reduce the environmental pollution and meet the needs for wearable electronic devices, new requirements for electromagnetic interference(EMI) shielding materials include flexibility, biodegradability, and biocompatibility. Herein, we reported a polypyrrole-coated zein/epoxy(PPy/ZE) ultrafine fiber mat which was inherently biodegradable and skin-friendly. In addition, it could maintain its ultrafine fibrous structure after coating, which could provide the mat with mechanical compliance, high porosity, and a large specific area for high EMI shielding. With the assistance of the epoxide cross-linking, the breaking stresses of the PPy/ZE fiber mats could achieve 3.3 MPa and 1.4 MPa and the strains were 40.1% and 83.0% in dry and wet states, respectively, which met the needs of various wearable electronic devices. Along with the extension in the PPy treatment duration, more PPy was loaded on the fiber surfaces, which formed more integrated and conductive paths to generate increasing conductivities up to 401.76 S·m^(-1). Moreover, the EMI shielding performance was raised to 26.84 dB. The biobased mats provide a green and efficient choice for EMI shielding materials, which may be a promising strategy to address EMI problems in multiple fields.
基金the Key Project of Chinese Ministry of Education (No. 104166)
文摘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.
文摘As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.
基金supported by E.S.E METROSALUD and Instituto Tecnologico Metropolitano—ITM.
文摘This paper presents a study on the effects of radiation from electronic equipment in hospitals. This study was performed in Argentinean, Colombian and Spanish hospitals. The work consists of two parts: a survey to determine the hospital personnel’s knowledge of the problem and a technical part consisting of a measurements campaign to determine the levels of radiated electrical and magnetic fields in several hospitals due to the presence of electromagnetic interferences, such as the use of mobile phones. The study of this problem has been of special interest in countries such as the USA and Canada, and this paper attempts to convey the necessity of creating regulations that can be applied to the hospitals of the countries analyzed. More than fifty hospitals were studied in these three countries, considering the following aspects: the hospital personnel’s awareness of the problem, whether the hospitals have performed previous studies of this type, the appearance of problems in medical equipment due to this interference, the origin of the interference, and the failures that have appeared in computers due to electromagnetic interference. The results show that, most hospitals have a lack of knowledge regarding this issue and that field levels above those allowed by international regulations are present. Therefore, a regulation must be established to avoid the problem.
基金Tianjin Natunal science Foundation of China(No:05YFSYSF033)
文摘As for the Domino effect dv/dt and electromagnetic interference during the rapid switching course of single-chip switching power supply,this article firstly analyzes electromagnetic interference source,and then diagnoses the essential interaction relationship between interference and switching activity based on the timely and area measured waveform,analyzes and studies the production mechanism and coupling path of interference mode,and sets up circuit model according to the features of transverse mode interference and common mode interference.Put forward different suppression methods finally.
基金Item Sponsored by National Natural Science Foundation of China(50274203)National High Technology Research and Development Program of China(2001AA337040)
文摘To design a power source system and mold for electromagnetic soft-contact continuous casting process and to theoretically estimate the heat losses from the charges and the system power, the effect of structure parameters on system power and magnetic flux density distribution was calculated using finite element method. The results show that as for electromagnetic soft-contact continuous casting system with partial-segment type mold, the power consumption is much more than that with a full-segment type mold; about 62% of electric power is dissipated in the mold, and the effective acting range of magnetic field is relatively narrow. Optimizing mold structure is a crucial measure of remarkably reducing mold power consumption and saving electric energy. Increasing slit number, width, and length can remarkably increase the magnetic flux density in the mold and can reduce the electric energy consumption. Among structure parameters, slit number and slit width are relatively more effective to reduce energy consumption. For a round billet electromagnetic continuous casting system with diameter of 178 ram, the reasonable slit number, width, and length are about 24--32, 0. 5--1.0 mm, and 160 mm, respectively.
基金National Natural Science Foundation of China (No. 50477009)
文摘A systematic approach to the design of the conducted electromagnetic interference (EMI) filter of high-density plasma cutting power supply has been developed. Converter components have been accurately modeled, with parasitic elements extracted to reveal their impacts on the EMI noises. Circuit simulations have been used to analyze and minimize the EMI noises. Conducted EMI noise measurement and filter design of this power supply have been achieved which successfully satisfy the FCC class B limits in the frequency range from 150 kHz to 30 MHz. The analyses and experimental results show that the designed filter guarantees that the required attenuation will be achieved.
文摘The surface modification on the AA6082 Al?Mg?Si aging-hardenable aluminum alloy was investigated by electricaldischarge alloying (EDA) process. Kerosene, used as a dielectric fluid, was pyrolytically decomposed into carbon for the formationof a self-lubricated carbide layer on the aluminum alloy surface during EDA process. Transmission electron microscopy (TEM)image found that the self-lubricated carbide layer was a multi-phase material with carbides and graphite. As a result, theEDA-modified aluminum alloy had a negligible wear rate of ~2?10?4 mg/m (c. f. ~1.1?10?2 mg/m for aluminum alloy substrate).Notably, a new characteristic was found that the EDA-processed carbide layer was a soft magnet, which improved theelectromagnetic interference (EMI) shielding performance of the alloy.
文摘The trajectory related and Direct Current(DC)Electromagnetic Interference(EMI)of lithium battery,fuel cell and photovoltaic modules has a great influence on the small-scale Unmanned Aerial Vehicle(UAV)airborne magnetometer and is hard to be shielded,calibrated or filtered.Besides,the mechanisms underlying the DC EMI have been rarely investigated yet.To cope with this problem,this paper systematically studies the EMI models,and proposes an online 3-layer EMI reduction scheme.First,EMI coupled with UAV motion model and hybrid power system is established.Second,the mechanism EMI models of hybrid power system are established and verified based on the proposed concept“equivalent current”.Third,an online 3-layer EMI reduction scheme is proposed,including battery layer,trajectory planning layer and energy management layer.In the first main layer,EMI self-cancellation is realized by rotating battery inclinations and symmetrical circuits.In response to errors,the trajectory planning layer reduces the EMI intensity by optimizing an optimal trajectory,while the energy management layer prioritizes power allocation to power sources that can produce small and stable EMI.Simulation results of climb,level flight and descent illustrate the efficaciousness and applicability of the proposed online 3-layer EMI reduction scheme.
文摘BACKGROUND Electromagnetic interference(EMI),means disturbance to the operation of implanted electrical devices caused by external sources.If cardiac pacemaker is implanted into the body,the risk of EMI should be considered when performing neuromuscular electrical stimulation(NMES).So far,no case has been reported that clinical magnets are used to safely manage the EMI risk of patients with cardiac pacemaker in NMES.CASE SUMMARY A 72-year-old male with swallowing disorder due to pure motor lacunar syndrome was transferred to rehabilitation department six days after the symptom onset.EMI risk needed be considered when implementing NMES on pharyngeal muscles,since cardiac pacemaker was implanted on his left chest due to the sick sinus syndrome.In the first NMES,the function of the pacemaker was directly monitored using telemetric instruments.From the second day,by a simple method of placing a magnet on the pacemaker,we chose to move the pacemaker into a mode that the device was not influenced by external stimulus.This magnet method has been used repeatedly for a year for the safe NMES treatment.We could remove Levin tube four months after the initial symptom and dysphagia related symptoms had not been noted during two-year follow-up period.CONCLUSION This report is the first case of dysphagia rehabilitation that EMI risk was handled using mode change of pacemaker with magnet.This method is unfamiliar to doctors,but safe and easy approach.This paper could be guidance for clinicians who need to treat patients with EMI risk.
文摘To investigate electromagnetic interference (EMI) of electromagnetic fields (EMF) from electronic article surveillance (EAS) systems with electronic implants numerical anatomical models of pacemaker patients were generated accounting for different implantation sites (left pectoral, right pectoral and abdominal) and body size. Induced interference voltages were calculated with a software package applying the Finite Integration Technique and analysed in dependence on frequency. Results were referred to reported maximum magnetic fields levels measured at EAS systems in the ELF, IF and RF range. With reference to electromagnetic immunity requirements of safety standards of implanted cardiac pacemakers and defibrillators, the numerical analysis showed that the relevance of interference depends on the applied EMF frequency. At EAS systems operating in the RF range, EMI and consequential inadequate pacing is rare but cannot be ruled out. The probability of such events increases at EAS systems in the IF range and even more in the ELF range. Since interference is encountered already at yet existing systems, the situation would be worse if future systems would further increase their emissions by making use of the elevated reference levels recommended in updated exposure guidelines.
基金supported by China Southern Power Grid Corporation,GrantNo.GDKJXM20185800the National Natural Science Foundation of China,Grant No.62073084.
文摘In order to solve the failure of electricity anti-stealing detection device triggered by the noise mixed in high-frequency electricity stealing signals,a denoising method based on variational mode decomposition(VMD)and wavelet threshold denoising(WTD)was applied to extract the effective high-frequency electricity stealing signals.First,the signal polluted by noise was pre-decomposed using the VMD algorithm,the instantaneous frequency means of each pre-decomposed components was analyzed,so as to determine the optimal K value.The optimal K value was used to decompose the polluted signal into K intrinsic mode components,and the sensitive mode components were determined through the cross-correlation function.Next,each sensitive mode was reconstructed.Finally,the reconstructed signal denoised using the wavelet threshold to obtain the denoised signal.The simulation analysis and experimental results show that the proposed method is superior to the traditional VMD method,FFT method and EMD method,as it can effectively eliminate the noise and enhance the reliability of high-frequency electricity stealing signal detection.