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Effect of pulsed electromagnetic frequency on the microstructure, wear and solid erosion resistance of CrAlN coatings deposited by arc ion plating 被引量:1
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作者 WANG Di LIN Song-sheng +5 位作者 LIU Ling-yun XUE Yu-na YANG Hong-zhi YANG Chao YANG Zhen ZHOU Ke-song 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第9期3065-3076,共12页
In this work,the chromium aluminum nitride(CrAlN)coatings were prepared on TC11 titanium alloy by composite magnetic field cathodic arc ion plating with controllable pulse electromagnetic combined with permanent magne... In this work,the chromium aluminum nitride(CrAlN)coatings were prepared on TC11 titanium alloy by composite magnetic field cathodic arc ion plating with controllable pulse electromagnetic combined with permanent magnet.The effects of electromagnetic frequency on the morphology,microstructure,nano-hardness and elastic modulus of the coatings were investigated by scanning electron microscope(SEM),X-ray diffraction(XRD)and nano-indenter.This paper has mainly studied the influence of CrAlN coatings which are prepared at various electromagnetic frequencies on the wear and erosion resistance through a series of wear and solid particle erosion experiments.It was found that the deposition rate of CrAlN coatings increases with the increase of electromagnetic frequency.And CrAlN coatings all preferentially grew along the(111)crystal plane.At 16.7 Hz,with the increase of pulsed electromagnetic frequency,the hardness is the highest(23.6 GPa)and the adhesion is the highest(41.5 N).In addition,the coating deposition exhibited the best wear and solid erosion resistance at 16.7 Hz and 33.3 Hz,the friction coefficient is about 0.35,and the erosion rate is about 0.2μm/g at 30°and less than 1μm/g at 90°,respectively.These results indicate that the CrAlN coating formed at an appropriate pulsed electromagnetic frequency can achieve excellent mechanical properties,wear and solid erosion resistance. 展开更多
关键词 CrAlN coating compound magnetic field pulse electromagnetic frequency mechanical property
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Production of super-high strength aluminum alloy billets by low frequency electromagnetic casting 被引量:6
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作者 张海涛 崔建忠 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2134-2139,共6页
The effects of low frequency electromagnetic field on the macro-physical fields in the semi-continuous casting process of aluminum alloys and the microstructure and crack in the billets were studied and analyzed by th... The effects of low frequency electromagnetic field on the macro-physical fields in the semi-continuous casting process of aluminum alloys and the microstructure and crack in the billets were studied and analyzed by the numerical and experimental methods.Comparison of the results for the macro-physical fields in the low frequency electromagnetic casting(LFEC) process with the conventional DC casting process indicates the following characters due to the application of electromagnetic field:an entirely changed direction and remarkably increased velocity of melt flow;a uniform distribution and a decreased gradient of temperature;elevated isothermal lines;a reduced sump depth;decreased stress and plastic deformation.Further,the microstructure of the billets is refined remarkably and the crack in the billets is eliminated in LFEC process because of modification of the macro-physical fields induced by the application of low frequency electromagnetic field. 展开更多
关键词 super-high strength aluminum alloy low frequency electromagnetic casting DC casting macro-physical field CRACK MICROSTRUCTURE
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EFFECT OF LOW-FREQUENCY ELECTROMAGNETIC FIELD ON THE AS-CASTING MICROSTRUCTURES AND MECHANICAL PROPERTIES OF HDC 2024 ALUMINUM ALLOY 被引量:4
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作者 Q.F. Zhu Z.H. Zhao J.Z. Cui Y.B. Zuo F. Qu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第3期205-210,共6页
The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were pro... The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field. 展开更多
关键词 Horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy MICROSTRUCTURES MACROSEGREGATION
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Application of pseudo-random frequency domain electromagnetic method in mining areas with strong interferences 被引量:7
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作者 Yan-fang HU Di-quan LI +2 位作者 Bo YUAN Guang-yun SUO Zi-jie LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第3期774-788,共15页
Due to the strong electromagnetic interferences and human interference,traditional electromagnetic methods cannot obtain high quality resistivity data of mineral deposits in Chinese mines.The wide field electromagneti... Due to the strong electromagnetic interferences and human interference,traditional electromagnetic methods cannot obtain high quality resistivity data of mineral deposits in Chinese mines.The wide field electromagnetic method(WFEM),in which the pseudo-random signal is taken as the transmitter source,can extract high quality resistivity data in areas with sever interference by only measuring the electric field component.We use the WFEM to extract the resistivity information of the Dongguashan mine in southeast China.Compared with the audio magnetotelluric(AMT)method,and the controlled source audio-frequency magnetotelluric(CSAMT) method,the WFEM can obtain data with higher quality and simpler operations.The inversion results indicate that the WFEM can accurately identify the location of the main ore-body,which can be used for deep mine exploration in areas with strong interference. 展开更多
关键词 pseudo-random signal frequency domain electromagnetic method wide field electromagnetic method(WFEM) strong interference anti-interference capability Dongguashan copper deposit
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Efects of low frequency electromagnetic ield on surface quality, microstructure and hot-tearing tendency of semi-continuous casting ZK60 magnesium alloy billets 被引量:3
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作者 Zhang Zhiqiang Le Qichi +1 位作者 Bao Lei Cui Jianzhong 《China Foundry》 SCIE CAS 2013年第6期351-354,共4页
The low frequency electromagnetic field was applied during direct chill(DC) semi-continuous casting of the ZK60 magnesium alloy billets. Effects of low frequency electromagnetic field on surface quality, microstructur... The low frequency electromagnetic field was applied during direct chill(DC) semi-continuous casting of the ZK60 magnesium alloy billets. Effects of low frequency electromagnetic field on surface quality, microstructure and hot-tearing tendency of Φ500 mm ZK60 magnesium alloy billets were investigated. The results showed that with the application of the low frequency electromagnetic field, the surface quality of the ZK60 magnesium alloy billets is markedly improved and the depth of cold fold is decreased. The microstructure of the billets is also significantly refined. Besides, the distribution of the grain size is relatively uniform from the billet surface towards its center, where the average grain size is 42 μm at surface and 50 μm at center. It also shows that the hot-tearing tendency of DC semi-continuous casting ZK60 magnesium alloy billets is significantly reduced under low frequency electromagnetic field. 展开更多
关键词 ZK60 magnesium alloy billets direct chill casting low frequency electromagnetic field REFINEMENT
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Prediction study of hydrocarbon reservoir based on time-frequency domain electromagnetic technique taking Ili Basin as an example 被引量:1
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作者 Tian Yu-Kun Zhou Hui +1 位作者 Ma Yan-Yan Li Juan 《Applied Geophysics》 SCIE CSCD 2020年第5期687-699,900,901,共15页
The time-frequency domain electromagnetic(TFEM)sounding technique can directly detect oil and gas characteristics through anomalies in resistivity and polarizability.In recent years,it has made some breakthroughs in h... The time-frequency domain electromagnetic(TFEM)sounding technique can directly detect oil and gas characteristics through anomalies in resistivity and polarizability.In recent years,it has made some breakthroughs in hydrocarbon detection.TFEM was applied to predict the petroliferous property of the Ili Basin.In accordance with the geological structure characteristics of the study area,a two-dimensional layered medium model was constructed and forward modeling was performed.We used the forward-modeling results to guide fi eld construction and ensure the quality of the fi eld data collection.We used the model inversion results to identify and distinguish the resolution of the geoelectric information and provide a reliable basis for data processing.On the basis of our results,key technologies such as 2D resistivity tomography imaging inversion and polarimetric constrained inversion were developed,and we obtained abundant geological and geophysical information.The characteristics of the TFEM anomalies of the hydrocarbon reservoirs in the Ili Basin were summarized through an analysis of the electrical logging data in the study area.Moreover,the oil-gas properties of the Permian and Triassic layers were predicted,and the next favorable exploration targets were optimized. 展开更多
关键词 Time–frequency Domain electromagnetic Hydrocarbon Detection Polarizability Anomaly Favorable Area Prediction
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Effect of Low Frequency Electromagnetic Field on Macrosegregation of Horizontal Direct Chill Casting Aluminum Alloys
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作者 Zhihao ZHAO, Jianzhong GUI, Jie DONG and Beijiang ZHANGThe Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, P.O. Box 314, Northeastern University, Shenyang 110004, ChinaPh.D. candidate, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第1期75-78,共4页
The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequen... The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequency electromagnetic field has been applied in HDC casting process and the relevant influence has been studied. The results show that application of low frequency electromagnetic field can reduce macrosegregation in HDC casting process; and two main parameters of electromagnetic field density and frequency, have great influences on the solution distribution along the diameter of ingot. Moreover, the mechanisms of reduction of macrosegregation by electromagnetic field have been discussed. 展开更多
关键词 Low frequency electromagnetic field Horizontal direct chill casting MACROSEGREGATION Aluminum alloy
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Effect of Middle-frequency Electromagnetic Field on the Semi-continuous Casting for ZK60 Billets
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作者 任政 张兴国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期449-453,共5页
The semi-continuous casting of ZK60 magnesium alloy under different middle frequency electromagnetic field conditions was examined.Effects of middle frequency electromagnetic field on microstructure,precipitations and... The semi-continuous casting of ZK60 magnesium alloy under different middle frequency electromagnetic field conditions was examined.Effects of middle frequency electromagnetic field on microstructure,precipitations and tensile properties are investigated.The results show that the microstructures of ZK60 magnesium alloy are refined and distribution uniformity of precipitations is observed after applying the middle frequency electromagnetic field.And the tensile properties of the billets produced by middle frequency electromagnetic field are increased. 展开更多
关键词 middle frequency electromagnetic field semi-continuous casting ZK60
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Methods of de-noising the low frequency electromagnetic data
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作者 王艳 《Journal of Measurement Science and Instrumentation》 CAS 2012年第1期62-65,共4页
The quality of the low frequency electromagnetic data is affected by the spike and the trend noises.Failure in removal of the spikes and the trends reduces the credibility of data explanation.Based on the analyses of ... The quality of the low frequency electromagnetic data is affected by the spike and the trend noises.Failure in removal of the spikes and the trends reduces the credibility of data explanation.Based on the analyses of the causes and characteristics of these noises,this paper presents the results of a preset statistics stacking method(PSSM)and a piecewise linear fitting method(PLFM)in de-noising the spikes and trends,respectively.The magnitudes of the spikes are either higher or lower than the normal values,which leads to distortion of the useful signal.Comparisons have been performed in removing of the spikes among the average,the statistics and the PSSM methods,and the results indicate that only the PSSM can remove the spikes successfully.On the other hand,the spectrums of the linear and nonlinear trends mainly lie in the low frequency band and can change the calculated resistivity significantly.No influence of the trends is observed when the frequency is higher than a certain threshold value.The PLSM can remove effectively both the linear and nonlinear trends with errors around 1% in the power spectrum.The proposed methods present an effective way for de-noising the spike and the trend noises in the low frequency electromagnetic data,and establish a research basis for de-noising the low frequency noises. 展开更多
关键词 SPIKE trend low frequency electromagnetic data DE-NOISING preset statistics stacking method(PSSM) piecewise linear fitting method(PLFM)
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Electromagnetic Resonance of Astigmatic Gaussian Beam to the High Frequency Gravitational Waves
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作者 仲元红 李瑾 +1 位作者 周瑶 雷绮仑 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第10期11-14,共4页
The high frequency gravitational waves (around lOS-lO12 Hz) could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux (PPF) of a... The high frequency gravitational waves (around lOS-lO12 Hz) could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux (PPF) of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio (SNR) would also be improved. When the eccentric ratio of waist satisfying w0x : w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux (i.e., SNR) can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36. 展开更多
关键词 of on IS in PPF electromagnetic Resonance of Astigmatic Gaussian Beam to the High frequency Gravitational Waves
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Radiation of Ultra Low Frequency Electromagnetic Waves from Atmosphere under the Influence of Strong Shock Waves
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作者 A. R. Aramyan S. A. Aramyan +2 位作者 S. G. Bilen L. Sh. Grigoryan H. F. Khachatryan 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第3期39-41,共3页
We present preliminary results from the experimental investigation of the response of the atmosphere due to the impact of powerful shock waves. The response is evidenced as ultra low frequency electromagnetic wave rad... We present preliminary results from the experimental investigation of the response of the atmosphere due to the impact of powerful shock waves. The response is evidenced as ultra low frequency electromagnetic wave radiation at frequency of 2-5 kHz and in duration of 3 7s. We hypothesize that this radiation appears due to the following process: the shock wave ionizes the neutral particles in the air and these charged and neutral particles continue their vertical motion, which forms in the trail of the shock wave. Such motion can cause the cyclotron-like radiation measured. 展开更多
关键词 Radiation of Ultra Low frequency electromagnetic Waves from Atmosphere under the Influence of Strong Shock Waves
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Analysis and Simulation of the Influence of Electromagnetic Fields on Living Beings near HV Power Lines Using the FDTD Method
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作者 Anthony Bassesuka Sandoka Nzao 《Open Journal of Applied Sciences》 2023年第12期2343-2359,共17页
Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-freque... Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-frequency electromagnetic fields on the environment and which are capable of modifying and destroying our ecosystem. Particular interest was given in this article due to a massive influx of population living near high voltage lines. The analysis and simulation of the influence of low frequency electromagnetic fields on living beings in the vicinity of high voltage sources 132 kV and 220 kV in urban areas in DR Congo is the subject of our research with a view to estimating the level of exposure of humans to low frequency electromagnetic fields. To carry out our research, we used the classic method of analyzing the field produced near a high voltage line based on Maxwell’s image theory, the Maxwell-Gauss theorem and Maxwell-Ampère theorem to model and quantify low-frequency electromagnetic fields in the vicinity of high-voltage lines. The 2D FDTD numerical formulation was developed from telegraphers’ equations and allowed us to obtain models of current and voltage induced by electromagnetic fields on living beings below and near HV lines. The different simulations carried out on the proposed models illustrate the effects of the electrical and geometric parameters of the pylons on the distribution of the electromagnetic field in the vicinity of the HV lines. The results obtained were compared to the safety limits recommended by the standards. 展开更多
关键词 Low frequency electromagnetic Field Modeling Field and Health Maxwell’s Equations FDTD Method electromagnetic Compatibility High Voltage Line
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DISCHARGE CHANNEL GROWTH IN MICRO EDM OF HIGH FREQUENCY PULSE 被引量:2
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作者 刘宇 王津 +1 位作者 王元刚 赵福令 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第4期353-361,共9页
The influences of intense magnetic pinch effect caused by electromagnetic field with high frequency on discharge channel expansion and plasma configuration change are discussed. The change of Lorentz force exerting on... The influences of intense magnetic pinch effect caused by electromagnetic field with high frequency on discharge channel expansion and plasma configuration change are discussed. The change of Lorentz force exerting on charged particles in discharge channel is calculated under the electromagnetic field with high frequency. Through the theoretical analysis and experimental study, the forming process of discharge channel is conjectured. And it is considered that the changes of discharge channel, such as the decrease of diameter and increase of energy density, coming from the intense magnetic pinch effect in high frequency electromagnetic field, are the main reasons for a series of special phenomena on the machined surface in micro EDM. 展开更多
关键词 micro EDM discharge channel high frequency electromagnetic field magnetic pinch effect discharge crater
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Direct-chilling casting of Mg alloy under electromagnetic and ultrasonic combined field 被引量:2
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作者 崔建忠 张志强 乐启炽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期297-305,共9页
The effects of low frequency electromagnetic (LFEC) field and ultrasonic (US) field on the microstructures, macrosegregation of alloying elements and the mechanical properties of DC cast AZ80 alloy were studied. The r... The effects of low frequency electromagnetic (LFEC) field and ultrasonic (US) field on the microstructures, macrosegregation of alloying elements and the mechanical properties of DC cast AZ80 alloy were studied. The results show that both LFEC and US fields can refine the grains of the billets, which results in the increase in mechanical properties and uniformity of alloying element distribution. The effective refinement takes place on the edge of ingots when LFEC field is applied, while in the center of billets when field US is adopted. Combined the characteristics of LFEC and US fields, a new process for direct-chilling (DC) casting of Mg-electromagnetic-ultrasonic (ECUS) casting is developed, by which the grains are refined significantly and are more uniform in the whole ingots, and the mechanical properties of the ingots are improved. 展开更多
关键词 low frequency electromagnetic field ultrasonic field Mg alloy DC casting
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Coupled Modeling of Electromagnetic Fleld,Fluid Flow,Heat Transfer and Solidification During Conventional DC Casting and Low Ftequency Electrmagnetic Casting of 7xxx Aluminum Alloys
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作者 Nagaum Hiromi 《特种铸造及有色合金》 CAS CSCD 北大核心 2008年第S1期485-490,共6页
A comprehensive mathematical model has been developed to describe the interaction of the multiple physics fields during the conventional DC casting and LFEC (low frequency electromagnetic casting) process. The model i... A comprehensive mathematical model has been developed to describe the interaction of the multiple physics fields during the conventional DC casting and LFEC (low frequency electromagnetic casting) process. The model is based on a combination of the commercial finite element package ANSYS and the commercial finite volume package FLUENT, with the former for the calculation of the electromagnetic field and the latter for the calculation of the magnetic driven fluid flow, heat transfer and solidification. Moreover, the model has been verified against the temperature measurements obtained from two 7XXX aluminum alloy billets of 200mm diameter, cast during the conventional DC casting and the LFEC casting processes. In addition, a measurement of the sump shape of the billets were carried out by using addition melting metal of Al-30%Cu alloy into the billets during casting process. There was a good agreement between the calculated results and the measured results. Further, comparison of the calculated results during the LFEC process with that during the conventional DC casting process indicated that velocity patterns, temperature profiles and the sump depth are strongly modified by the application of a low frequency electromagnetic field during the DC casting. 展开更多
关键词 low frequency electromagnetic casting DC casting coupled modeling temperature field fluid flow solidification.
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Effects of Different Electromagnetic Fields on Circadian Rhythms of Some Haematochemical Parameters in Rats
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作者 LAURA CONTALBRIGO CALOGERO STELLETTA +4 位作者 LAURA FALCIONI STEFANIA CASELLA GIUSEPPE PICCIONE MORANDO SOFFRITTI AND MASSIMO MORGANTE 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2009年第4期348-353,共6页
Objective To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats. Methods The study was carried out in 18 male and 18 female rats ... Objective To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats. Methods The study was carried out in 18 male and 18 female rats in good health conditions exposed to 50 Hz magnetic sinusoid fields at the intensity of 1000 μT, 100 μT, and 0 μT (control group) respectively, and in 18 male and 18 female rats in good health conditions exposed to 1.8 GHz electromagnetic fields at the intensity of 50 V/m, 25 V/m and 0 V/m (control group), respectively. Following haematochemical parameters for glucose, triglycerides, and total cholesterol were measured. Results Different effects of electromagnetic fields on circadian rhythms of both male and female rats were observed. Different changes occurred in some haematochemical parameters for glucose, triglycerides, and total cholesterol (P〈0.05). Conclusion Exposure to different electromagnetic fields is responsible for the variations of some haematochemical parameters in rats. 展开更多
关键词 Extremely low frequency electromagnetic fields (50 Hz) Radiofrequency electromagnetic fields (1.8 GHz) Haematochemical parameters Circadian rhythm Sprague-Dawley rat
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Ultra low frequeney electromagnetic wave anomaly and its spectrum characteristics before earthquakes
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作者 郝建国 张云福 +3 位作者 潘怀文 李德瑞 唐天明 刘小芹 《Acta Seismologica Sinica(English Edition)》 CSCD 1995年第1期101-109,共9页
Many observations and researches show that abundant and intense ultra low frequency (ULF) electromagneticanomalies appears before local earthquakes. In order to understand this phenomenon systematically, the trans-mis... Many observations and researches show that abundant and intense ultra low frequency (ULF) electromagneticanomalies appears before local earthquakes. In order to understand this phenomenon systematically, the trans-mission property and the formation of the seismic-electric dipole are discussed in this paper. The results showthat the vertical component Of the ULF electric anomaly before earthquake has the properties of better penetration, less disturbance and high signal-to-noise ratio. The signal can be easily extracted and received. The anomaly should be an important way to seek for reliable short-term and imminent earthquake precursors. After thespectrum analysis of the (ULF) electric field anomalies, we found that the periods of the anomaly related to localearthquakes are from a few minutes to a dozens minutes. There is a relation between the spectrum of the anomaly and the epicentral distance. The ULF electric field anomalies strongly rely on the orientation of the seismo-genie zone. The percolation electric field anomaly and its spectrum amplitude do not have obvious relation withthe size of local earthquakes. 展开更多
关键词 earthquake precursor frequency spectrum electromagnetic method atmospheric electric field
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A Real-time EMF Measuring System for Mobile Communication Towers in Sri Lanka 被引量:1
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作者 Lakshitha Rangana WICKRAMASINGHE Sisaara PERERA 《Instrumentation》 2021年第2期22-33,共12页
Telecommunications Regulatory Commission of Sri Lanka is the governing body which is responsible for the frequency allocation and monitoring the unauthorized Electromagnetic frequency(EMF)signal transmitting violation... Telecommunications Regulatory Commission of Sri Lanka is the governing body which is responsible for the frequency allocation and monitoring the unauthorized Electromagnetic frequency(EMF)signal transmitting violations.However,in Sri Lanka,currently there is not any proper mechanism to monitor the radiation hazard level and its impact to the people living in the vicinity of mobile communication towers.There are approximately 7000 mobile transmitting towers in Sri Lanka to date and the used frequency range lies between 900 MHz to 3 GHz for mobile communication.Over the last few decades,many of the health hazard conditions were reported due to the radiation of those harmful EMFs.To cater this problem,a portable real time EMF signal strength measuring system with a radiation hazard level indicator was developed to monitor the EMF level and its impact.The proposed system operates with three intermediate frequency bands(i.e.900 MHz,1800 MHz and 2400 MHz)and it’s capable of measuring the power density and the radiation hazard level at that particular point which is being measured.Moreover,the corresponding radiation hazard level is indicated with reference to the standard power density levels published by the International Commission on Non-Ionizing Radiation Protection(ICNIRP^(*)).The system works with the overall accuracy of 88%in terms of identifying the power densities and its corresponding radiation hazard levels. 展开更多
关键词 electromagnetic frequency(EMF) Mobile Communication Power Density Radiation Hazard
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DC casting of light alloys under magnetic fields 被引量:2
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作者 崔建忠 张志强 乐启炽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第11期2046-2050,共5页
The working principle of LFEC(Low frequency electromagnetic casting) process developed in Northeastern University, China was introduced and the metallurgical results of LFEC were discussed according to the casting p... The working principle of LFEC(Low frequency electromagnetic casting) process developed in Northeastern University, China was introduced and the metallurgical results of LFEC were discussed according to the casting practices. The low frequency field around the mold produces Lorenz force, which can be divided into two parts: one is the potential force which will be balanced by a pressure gradient of the liquid and results in the formation of a convex surface meniscus and improves the surface quality; the other is the rotary force which stirs the liquid in the mold to refine the microstructures and homogenize the distribution of alloying elements. LFEC can refine microstructures remarkably, improve surface quality of the ingots, depress macrosegregation and eliminate cracks. Some new technologies, such as horizontal direct chill casting under low-frequency electromagnetic field (HLEC), DC casting of hollow billets under electromagnetic fields (HBEC), electromagnetic modifying of hypereutectic A1-Si alloys(EMM), air film casting under static magnetic field (AFCM), and multi-ingots casting under low-frequency magnetic field (MLFEC) were developed based on LFEC. 展开更多
关键词 low frequency electromagnetic field light alloy DC casting grain refinement
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LFEC and LFEVC of AZ80 magnesium alloy 被引量:1
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作者 LE Qichi,CUI Jianzhong,ZHANG Zhiqiang,and GUO Shijie Key Laboratory of EPM,Northeastern University,Shenyang 110004,China 《Rare Metals》 SCIE EI CAS CSCD 2007年第S1期109-114,共6页
The effects of a low frequency electromagnetic field and a low frequency electromagnetic vibration field applied during DC casting of AZ80 Mg on microstructures and alloying element distribution in ingots were investi... The effects of a low frequency electromagnetic field and a low frequency electromagnetic vibration field applied during DC casting of AZ80 Mg on microstructures and alloying element distribution in ingots were investigated.The experiments were performed both in absence and in the presence of the magnetic fields.In DC casting,the ingot exhibited coarse microstructure and severe segregation of Al.In the presence of solo low frequency alternating magnetic field,namely LFEC,the grains of the ingot was effectively refined and the segregation of Al was significantly decreased.In LFEVC,namely low frequency electromagnetic vibration casting,the ingot were significantly refined and the segregation was suppressed.With increasing the vibration intensities,the grain refinement and segregation suppression were increased. 展开更多
关键词 DC casting low frequency electromagnetic casting(LFEC) low frequency electromagnetic vibration(LFEVC) MICROSTRUCTURES SEGREGATION
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