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Full magnetic gradient tensor from triaxial aeromagnetic gradient measurements:Calculation and application 被引量:5
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作者 骆遥 吴美平 +4 位作者 王平 段树岭 刘浩军 王金龙 安战锋 《Applied Geophysics》 SCIE CSCD 2015年第3期283-291,465,共10页
The full magnetic gradient tensor (MGT) refers to the spatial change rate of the three field components of the geomagnetic field vector along three mutually orthogonal axes. The tensor is of use to geological mappin... The full magnetic gradient tensor (MGT) refers to the spatial change rate of the three field components of the geomagnetic field vector along three mutually orthogonal axes. The tensor is of use to geological mapping, resources exploration, magnetic navigation, and others. However, it is very difficult to measure the full magnetic tensor gradient using existing engineering technology. We present a method to use triaxial aeromagnetic gradient measurements for deriving the full MGT. The method uses the triaxial gradient data and makes full use of the variation of the magnetic anomaly modulus in three dimensions to obtain a self-consistent magnetic tensor gradient. Numerical simulations show that the full MGT data obtained with the proposed method are of high precision and satisfy the requirements of data processing. We selected triaxial aeromagnetic gradient data from the Hebei Province for calculating the full MGT. Data processing shows that using triaxial tensor gradient data allows to take advantage of the spatial rate of change of the total field in three dimensions and suppresses part of the independent noise in the aeromagnetic gradient. The calculated tensor components have improved resolution, and the transformed full tensor gradient satisfies the requirement of geological mapping and interpretation. 展开更多
关键词 Aeromagnetic gradient full magnetic gradient tensor triaxial aeromagnetic gradiometer. tensor invariant
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Three direction analytical signal analysis method of magnetic gradient tensor and application in the interpretation 被引量:3
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作者 Guo Can-wen Xing Zhe +2 位作者 Wang Lin-fei Ma Yong Huan Heng-fei 《Applied Geophysics》 SCIE CSCD 2020年第2期285-296,317,共13页
Compared to conventional magnetic data,magnetic gradient tensor data contain more high-frequency signal components,which can better describe the features of geological bodies.The directional analytic signal of the mag... Compared to conventional magnetic data,magnetic gradient tensor data contain more high-frequency signal components,which can better describe the features of geological bodies.The directional analytic signal of the magnetic gradient tensor is not easily interfered from the tilting magnetization,but it can infer the range of the fi eld source more accurately.However,the analytic signal strength decays faster with depth,making it diffi cult to identify deep fi eld sources.Balanced-boundary recognition can eff ectively overcome this disadvantage.We present here a balanced-boundary identifi cation technique based on the normalization of three-directional analytic signals from aeromagnetic gradient tensor data.This method can eff ectively prevent the fast attenuation of analytic signals.We also derive an Euler inversion algorithm of three-directional analytic signal derivative.By combining magnetic-anomaly model testing with the traditional magnetic anomaly interpretation method,we show that the boundary-recognition technology based on a magnetic gradient tensor analytic signal has a greater advantage in identifying the boundaries of the geological body and can better refl ect shallow anomalies.The characteristics of the Euler equation based on the magnetic anomaly direction to resolve the signal derivative have better convergence,and the obtained solution is more concentrated,which can obtain the depth and horizontal range information of the geological body more accurately.Applying the above method to the measured magneticanomaly gradient data from Baoding area,more accurate fi eld source information is obtained,which shows the feasibility of applying this method to geological interpretations. 展开更多
关键词 magnetic gradient tensor analytic signal edge detection
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Assessment of Vertical Magnetic Gradient Data of Tuzla Fault Using Boundary Analysis and 3-D Inversion Techniques
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作者 Emre Timur 《Journal of Power and Energy Engineering》 2017年第12期33-45,共13页
The magnetic prospection is one of the most useful methods to determine buried geological structures such as shallow fracture zones. The investigation of vertical and horizontal gradient and total magnetic field varia... The magnetic prospection is one of the most useful methods to determine buried geological structures such as shallow fracture zones. The investigation of vertical and horizontal gradient and total magnetic field variations over geological structures, which have been used for many years, may reveal their locations, geometries and physical characteristics. In this study, a proposed iterative 3-D rectangular prismatic model inversion algorithm was modified to interpret vertical magnetic gradient data defining the boundaries and the physical parameters of the anomalous structure. Vertical magnetic gradient measurements were carried out at the Tuzla fault, an active fault system located along NE-SW direction in Izmir (Turkey). Boundary analysis studies were applied to data in order to obtain boundaries of the structures, afterwards the inversion process was carried out considering these geometries. As a result, location, direction and other physical and geometrical features of the fault are achieved. 展开更多
关键词 Boundary Analysis GEOTHERMAL lnversion magnetic gradient Tuzla Fault
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Effects of gradient high-field static magnetic fields on diabetic mice 被引量:5
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作者 Biao Yu Chao Song +11 位作者 Chuan-Lin Feng Jing Zhang Ying Wang Yi-Ming Zhu Lei Zhang Xin-Miao Ji Xiao-Fei Tian Guo-Feng Cheng Wei-Li Chen Vitalii Zablotskii Hua Wang Xin Zhang 《Zoological Research》 SCIE CAS CSCD 2023年第2期249-258,共10页
Although 9.4 T magnetic resonance imaging(MRI) has been tested in healthy volunteers,its safety in diabetic patients is unclear.Furthermore,the effects of high static magnetic fields(SMFs),especially gradient vs.unifo... Although 9.4 T magnetic resonance imaging(MRI) has been tested in healthy volunteers,its safety in diabetic patients is unclear.Furthermore,the effects of high static magnetic fields(SMFs),especially gradient vs.uniform fields,have not been investigated in diabetics.Here,we investigated the consequences of exposure to 1.0-9.4 T high SMFs of different gradients(>10 T/m vs.0-10 T/m)on type 1 diabetic(T1D) and type 2 diabetic(T2D) mice.We found that 14 h of prolonged treatment of gradient(as high as 55.5 T/m) high SMFs(1.0-8.6 T) had negative effects on T1D and T2D mice,including spleen,hepatic,and renal tissue impairment and elevated glycosylated serum protein,blood glucose,inflammation,and anxiety,while 9.4 T quasi-uniform SMFs at 0-10 T/m did not induce the same effects.In regular T1D mice(blood glucose>16.7 mmol/L),the>10 T/m gradient high SMFs increased malondialdehyde(P<0.01) and decreased superoxide dismutase(P<0.05).However,in the severe T1D mice(blood glucose≥30.0 mmol/L),the>10 T/m gradient high SMFs significantly increased tissue damage and reduced survival rate.In vitro cellular studies showed that gradient high SMFs increased cellular reactive oxygen species and apoptosis and reduced MS-1 cell number and proliferation.Therefore,this study showed that prolonged exposure to high-field(1.0-8.6 T)>10 T/m gradient SMFs(35-1 380 times higher than that of current clinical MRI)can have negative effects on diabetic mice,especially mice with severe T1D,whereas 9.4 T high SMFs at 0-10T/m did not produce the same effects,providing important information for the future development and clinical application of SMFs,especially high-field MRI. 展开更多
关键词 Type 2 diabetes Type 1 diabetes magnetic resonance imaging(MRI) gradient static magnetic field Quasi-uniform static magnetic field
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Growth Rate of a-Si∶H Film Influenced by Magnetic Field Gradient in MWECR CVD Plasma System 被引量:2
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作者 胡跃辉 吴越颖 +3 位作者 陈光华 王青 张文理 阴生毅 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第6期613-619,共7页
The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic ... The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic field profiles is obtained quantitatively by using Lorentz fit.The results indicate that the gradient value of the magnetic field profile near by the substrate,which is produced by a coil current with 137.7A if a SmCo permanent magnet is equipped under the substrate holder,is the largest;when the SmCo permanent magnet is taken away,the larger one is produced by the coil current with 137.7A and the smallest one produced by a coil current with 115.2A.High deposition rate of a-Si∶H film is observed near by the substrate with high magnetic field gradient.But uneven deposition rate along the radius of the sample holder is also found by infrared analysis technology when sample is deposited in magnetic field profile,which is produced by the coil current with 137.7A if the SmCo permanent magnet is equipped under the substrate holder. 展开更多
关键词 magnetic field gradient Lorentz fit a-Si∶H film deposition rate MWECR CVD deposition system
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Calculation and correction of magnetic object positioning error caused by magnetic field gradient tensor measurement 被引量:5
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作者 WANG Sansheng ZHANG Mingji +1 位作者 ZHANG Ning GUO Qiang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期456-461,共6页
Magnetic field gradient tensor measurement is an important technique to obtain position information of magnetic objects. When using magnetic field sensors to measure magnetic field gradient as the coefficients of tens... Magnetic field gradient tensor measurement is an important technique to obtain position information of magnetic objects. When using magnetic field sensors to measure magnetic field gradient as the coefficients of tensor, field differentiation is generally approximated by field difference. As a result, magnetic objects positioning by magnetic field gradient tensor measurement always involves an inherent error caused by sensor sizes, leading to a reduction in detectable distance and detectable angle. In this paper, the inherent positioning error caused by magnetic field gradient tensor measurement is calculated and corrected by iterations based on the systematic position error distribution patterns. The results show that, the detectable distance range and the angle range of an ac magnetic object(2.44 Am^2@1 kHz) can be increased from(0.45 m, 0.75 m),(0?, 25?) to(0.30 m, 0.80 m),(0?,80?), respectively. 展开更多
关键词 magnetic dipole magnetic gradient tensor positioning error error correction
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Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap 被引量:2
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作者 王婧 何军 +4 位作者 邱英 杨保东 赵江艳 张天才 王军民 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第6期2062-2065,共4页
Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or l... Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap. 展开更多
关键词 single atoms magneto-optical trap large magnetic gradient loading rate
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Magnetic susceptibility inversion method with full tensor gradient data using low-temperature SQUIDs 被引量:1
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作者 Yan-Fei Wang Liang-Liang Rong +2 位作者 Long-Qing Qiu D.V.Lukyanenko A.G.Yagola 《Petroleum Science》 SCIE CAS CSCD 2019年第4期794-807,共14页
Full tensor magnetic gradient measurements are available nowadays. These are essential for determining magnetization parameters in deep layers. Using full or partial tensor magnetic gradient measurements to determine ... Full tensor magnetic gradient measurements are available nowadays. These are essential for determining magnetization parameters in deep layers. Using full or partial tensor magnetic gradient measurements to determine the subsurface properties, e.g., magnetic susceptibility, is an inverse problem. Inversion using total magnetic intensity data is a traditional way.Because of di culty in obtaining the practical full tensor magnetic gradient data, the corresponding inversion results are not so widely reported. With the development of superconducting quantum interference devices(SQUIDs), we can acquire the full tensor magnetic gradient data through field measurements. In this paper, we study the inverse problem of retrieving magnetic susceptibility with the field data using our designed low-temperature SQUIDs. The solving methodology based on sparse regularization and an alternating directions method of multipliers is established. Numerical and field data experiments are performed to show the feasibility of our algorithm. 展开更多
关键词 Full tensor magnetic gradient Susceptibility Sparse regularization
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APPLICATION OF HIGH-RESOLUTION MAGNETIC METHOD AND GRADIENT METHOD TO LOCATE ABANDONED BRINE-WELLS IN HUTCHINSON, KANSAS, U.S.A.
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作者 CHEN Chao XIA Jianghai +2 位作者 XIA Sihao David Laflen Stephen L. Williams 《工程地球物理学报》 2004年第1期17-25,共9页
After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic meth... After successfully locating one abandoned brine well by an electromagnetic method during testing in 2001 and five abandoned brine wells by a high resolution magnetic method during 2002, a high resolution magnetic method was again proposed to search for wells in 2003 when a second sensor was employed to acquire data for calculating the pseudo vertical gradient of magnetic fields. Total area surveyed in 2003 was 1,024,000 ft 2, which was divided into grids with an average size of 10,000 ft 2 and distributed across eight different sites. Magnetic anomalies and their vertical gradients from known brine wells were first recorded as signatures to identify anomalies caused by possible buried brine wells. Of fifty one verified anomalies, thirty one anomalies were due to wells buried at depths from 0 to 8.5 ft: twenty one 6 to 9 inch abandoned brine wells, seven 1.5 to 3 inch probable water wells, one 16 inch dewatering well for a construction site at a depth of 3 ft, and two 4 inch wells on the ground surface. Approximate monopole shaped anomalies were observed from all these wells after data corrections. However, the range of amplitudes of magnetic anomalies from 7,000 to 28,000 nT from these abandoned brine wells was measured. This range of anomalies is mainly due to the thickness and depth of buried wells. Anomaly amplitudes from 1.5 to 3 inch wells are 4,000 to 8,000 nT and linearly correlate with the buried depth. One 3 inch well that caused an anomaly of 13,000 nT could be the inner pipe of a brine well. Gradient anomalies are roughly in a range of 100 to 200 nT/inch for 1.5 to 3 inch wells and 200 to 300 nT/inch for brine wells.As indicated by the potential field theory, gradient data possess higher horizontal resolution than the magnetic field itself. Gradient data provide valuable assistance in determining horizontal locations of anomaly sources for excavation. In practice, however, improvement in the horizontal resolution is limited by survey line spacing. If only one sensor is used in a survey, there is rapid decrease in the horizontal resolution when sensor height increases from 14 to 44 inches. This indicates that it is critical to keep the sensor as close to the ground as possible when hunting buried wells that are close to each other. It also suggests that the downward continuation is useful to increase the horizontal resolution in well hunting. 展开更多
关键词 High resolution magnetic method magnetic gradient method Brine Well
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High-gradient magnetic field-controlled migration of solutes and particles and their effects on solidification microstructure:A review 被引量:7
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作者 Tie Liu Qiang Wang +2 位作者 Yi Yuan Kai Wang Guojian Li 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期92-103,共12页
We present a review of the principal developments in the evolution and synergism of solute and particle migration in a liquid melt in high-gradient magnetic fields and we also describe their effects on the solidificat... We present a review of the principal developments in the evolution and synergism of solute and particle migration in a liquid melt in high-gradient magnetic fields and we also describe their effects on the solidification microstructure of alloys.Diverse areas relevant to various aspects of theory and applications of high-gradient magnetic field-controlled migration of solutes and particles are surveyed.They include introduction,high-gradient magnetic field effects,migration behavior of solute and particles in high-gradient magnetic fields,microstructure evolution induced by high-gradient magnetic fieldcontrolled migrations of solute and particles,and properties of materials modified by high-gradient magnetic field-tailored microstructure.Selected examples of binary and multiphase alloy systems are presented and examined,with the main focus on the correlation between the high-gradient magnetic field-modified migration and the related solidification microstructure evolution.Particular attention is given to the mechanisms responsible for the microstructure evolution induced by highgradient magnetic fields. 展开更多
关键词 high gradient magnetic field migration of solute and particle SOLIDIFICATION microstructure
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Innovative pre-concentration technology for recovering ultrafine ilmenite using superconducting high gradient magnetic separator 被引量:5
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作者 Zhitao Yuan Xuan Zhao +2 位作者 Jiwei Lu Hong Lv Lixia Li 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第6期1043-1052,共10页
To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was propos... To achieve the utilization of the abandoned ultrafine ilmenite(-20 μm) produced in the titanium magnetite processing plant in Panzhihua,the superconducting high-gradient magnetic separation(SMS) technology was proposed in this study.After optimizing the conditions of magnetic intensity,feeding and pulsation,an SMS concentrate with TiO_(2) grade of 16.03% and TiO_(2) recovery of 66.39% was obtained through one roughing-one cleaning pre-concentration flowsheet.The specific magnetic force and magnetic force were calculated and analysed to illustrate the pre-concentration mechanism,and the results revealed that the combination of high magnetic field and strong pulsating resulted in the effective preconcentration of the ultrafine ilmenite in the SMS process.In addition,the magnetic force analysis indicated that the high magnetic intensity and high magnetic gradient are the key factors of the SMS technology.Furthermore,the EDS-Mapping detection certified that the ultrafine ilmenite was concentrated from the gangue minerals using SMS technology. 展开更多
关键词 Ultrafine ilmenite Superconducting high gradient magnetic separation PRE-CONCENTRATION EDS-Mapping
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Removal of phosphate from municipal sewage by high gradient magnetic separation 被引量:2
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作者 黄自力 胡岳华 +1 位作者 徐竞 郑春华 《Journal of Central South University of Technology》 2004年第4期391-394,共4页
The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, ... The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, magnetic field intensity, pH value and flow-rate of sewage on phosphorus removal rate were investigated. The results show that addition of 200 mg/L Al2(SO4)3·18H2O and 300 mg/L Fe3O4, magnetic field intensity of 200 kA/m, pH value of 4.57.0 and flow-rate of 6.15 cm/s are both efficient and economic technical parameters for removal of phosphate. The pH value has a tremendous effect on the removal of phosphate. In the pH range of (4.5)7.0, more than 95% phosphate can be removed. Theoretical analysis indicates that the solubility of AlPO4 is minimum at pH 4.07.0 and the electrostatic attractive force between AlPO4 and Fe3O4 is maximum at pH 4.5(6.5.) 展开更多
关键词 REMOVAL PHOSPHATE municipal sewage high gradient magnetic separation
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Effect of Raman-pulse duration related to the magnetic field gradient in high-precision atom gravimeters
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作者 Yuan Cheng Yu-Jie Tan +3 位作者 Min-Kang Zhou Xiao-Chun Duan Cheng-Gang Shao Zhong-Kun Hu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期137-145,共9页
The effect of the Raman-pulse duration related to the magnetic field gradient, as a systematic error, is playing an important role on evaluating the performance of high-precision atomic gravimeters. We study this effe... The effect of the Raman-pulse duration related to the magnetic field gradient, as a systematic error, is playing an important role on evaluating the performance of high-precision atomic gravimeters. We study this effect with a simplified theoretical model of the time-propagation operator. According to the typical parameters, we find that this effect should be taken into account when the gravimeter reaches an accuracy of 10^-10g, and the larger the pulse duration is, the more obvious the systematic effect will be. Finally, we make a simple discussion on the possibility of testing this effect. 展开更多
关键词 atom gravimeters magnetic field gradient Raman-pulse duration time-propagation operator
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In-situ measurement of magnetic field gradient in a magnetic shield by a spin-exchange relaxation-free magnetometer
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作者 房建成 王涛 +2 位作者 张红 李阳 蔡洪炜 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期253-258,共6页
A method of measuring in-situ magnetic field gradient is proposed in this paper. The magnetic shield is widely used in the atomic magnetometer. However, there is magnetic field gradient in the magnetic shield, which w... A method of measuring in-situ magnetic field gradient is proposed in this paper. The magnetic shield is widely used in the atomic magnetometer. However, there is magnetic field gradient in the magnetic shield, which would lead to additional gradient broadening. It is impossible to use an ex-situ magnetometer to measure magnetic field gradient in the region of a cell, whose length of side is several centimeters. The method demonstrated in this paper can realize the in-situ measurement of the magnetic field gradient inside the cell, which is significant for the spin relaxation study. The magnetic field gradients along the longitudinal axis of the magnetic shield are measured by a spin-exchange relaxation-free (SERF) magnetometer by adding a magnetic field modulation in the probe beam's direction. The transmissivity of the cell for the probe beam is always inhomogeneous along the pump beam direction, and the method proposed in this paper is independent of the intensity of the probe beam, which means that the method is independent of the cell's transmissivity. This feature makes the method more practical experimentally. Moreover, the AC-Stark shift can seriously degrade and affect the precision of the magnetic field gradient measurement. The AC-Stark shift is suppressed by locking the pump beam to the resonance of potassium's D1 line. Furthermore, the residual magnetic fields are measured with σ+- and σ--polarized pump beams, which can further suppress the effect of the AC-Stark shift. The method of measuring in-situ magnetic field gradient has achieved a magnetic field gradient precision of better than 30 pT/mm. 展开更多
关键词 spin-exchange relaxation-free atomic magnetometer magnetic field gradient magnetic shield AC-Stark shift
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On the Gradient of the Electron Pressure in Anti-Parallel Magnetic Reconnection
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作者 王焕宇 黄灿 +1 位作者 陆全明 王水 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第4期65-68,共4页
We first perform a two-dimensional particle-in-cell simulation of anti-parallel magnetic reconnection to verify that in the electron diffusion region the reconnection electric field is mainly balanced by the gradient ... We first perform a two-dimensional particle-in-cell simulation of anti-parallel magnetic reconnection to verify that in the electron diffusion region the reconnection electric field is mainly balanced by the gradient of the electron pressure. Then, by following typical electron trajectories in the fixed electromagnetic field of anti- parallel reconnection, we calculate the gradient of the electron pressure. We find that the resulted gradient of the electron pressure is equal to the reconnection electric field. This indicates that in the electron diffusion region the reconnection electric field is balanced by the gradient of the electron pressure, which results from the electron nongyrotropic motions. Our result gives a microphysical explanation of the balance between the reconnection electric field and the gradient of the electron pressure. 展开更多
关键词 On the gradient of the Electron Pressure in Anti-Parallel magnetic Reconnection
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Effect of gradient magnetic field on physiochemistry functions of rice seedlings
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《Chinese Rice Research Newsletter》 1999年第1期10-10,共1页
Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged... Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged in eachother south and north pole.The magneticstrength was 0-40 mT.Each four varieties wasput under the magnetic plate 15 cm away,andwent through the magnetic field with the speedof 20 cm/s.The same varieties without thetreatment were used as CK.Both of the seedswere soaked in water for 48 h in room temper-ature,and then sprouted on the porcelain platewith absorbed water paper.When the 展开更多
关键词 Effect of gradient magnetic field on physiochemistry functions of rice seedlings
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Application of empirical mode decomposition in early diagnosis of magnetic memory signal 被引量:2
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作者 冷建成 徐敏强 张嘉钟 《Journal of Central South University》 SCIE EI CAS 2010年第3期549-553,共5页
In order to eliminate noise interference of metal magnetic memory signal in early diagnosis of stress concentration zones and metal defects, the empirical mode decomposition method combined with the magnetic field gra... In order to eliminate noise interference of metal magnetic memory signal in early diagnosis of stress concentration zones and metal defects, the empirical mode decomposition method combined with the magnetic field gradient characteristic was proposed. A compressive force periodically acting upon a casing pipe led to appreciable deformation, and magnetic signals were measured by a magnetic indicator TSC-1M-4. The raw magnetic memory signal was first decomposed into different intrinsic mode functions and a residue, and the magnetic field gradient distribution of the subsequent reconstructed signal was obtained. The experimental results show that the gradient around 350 mm represents the maximum value ignoring the marginal effect, and there is a good correlation between the real maximum field gradient and the stress concentration zone. The wavelet transform associated with envelop analysis also exhibits this gradient characteristic, indicating that the proposed method is effective for early identifying critical zones. 展开更多
关键词 metal magnetic memory noise interference early diagnosis empirical mode decomposition magnetic field gradient stress concentration ZONES envelop analysis
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Magnetic field characteristics analysis of a single assembled magnetic medium using ANSYS software 被引量:6
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作者 Ren Liuyi Zeng Shanglin Zhang Yimin 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期479-487,共9页
The section shape of an assembled magnetic medium is the most important structural parameter of a high gradient magnetic separator, which directly affects the induction distribution and magnetic field gradient of the ... The section shape of an assembled magnetic medium is the most important structural parameter of a high gradient magnetic separator, which directly affects the induction distribution and magnetic field gradient of the magnetic separator. In this study, equilateral triangle, square, hexagonal, octagon, dodecagon, and round shape sections of the assembled magnetic medium are chosen to study their influence on magnetic field distribution characteristics using the ANSYS analysis. This paper utilizes a single assembled magnetic medium to understand the relationship between the geometry of the assembled magnetic medium and its magnetic field distribution characteristics. The results show that high magnetic field,regional field, magnetic field gradient, and magnetic force formed by the different sections of the assembled magnetic medium in the same background magnetic field reduce in turn based on the triangle,square, hexagonal, octagon, dodecagon, and round. Based on the magnetic field characteristics analytic results, the magnetic separation tests of the ilmenite are carried out. The results indicate that the section shape of the toothed plate compared with the section shape of cylinder can improve the recovery of ilmenite up to 45% in the same magnetizing current condition of 2A, which is consistent with magnetic field characteristics analysis of different assembled magnetic medium section shapes. 展开更多
关键词 magnetic separation magnetic medium magnetic field character High gradient magnetic separator ANSYS
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Effects of 3.7 T-24.5 T high magnetic fields on tumor-bearing mice 被引量:1
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作者 Xiaofei Tian Ze Wang +5 位作者 Lei Zhang Chuanying Xi Li Pi Ziping Qi Qingyou Lu Xin Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第11期649-658,共10页
Since high magnetic field(MF) intensity can improve the image quality and reduce magnetic resonance imaging(MRI) acquisition time, the field intensity of MRIs has continued to increase over the past few decades. A... Since high magnetic field(MF) intensity can improve the image quality and reduce magnetic resonance imaging(MRI) acquisition time, the field intensity of MRIs has continued to increase over the past few decades. Although MRIs in most current hospitals are 0.5 T–3 T, there are preclinical studies have been carried out using 9.4 T MRI, and engineers are also putting efforts on building MRIs with even higher MFs. However, the accompanied safety issue of high-field MRIs is an emergent question to address before their clinical applications. In the meantime, the static magnetic field(SMF) has been shown to inhibit tumor growth in previous studies. Here, we investigated both the safety issue and the anti-tumor potentials of 3.7 T–24.5 T SMFs on GIST-T1 gastrointestinal stromal tumor-bearing nude mice. We followed up the mice three weeks after their exposure to high SMF and found that none of the mice died or had severe organ damage, except for slightly decreased food intake, weight gain, and liver function. Moreover, the tumor growth was inhibited by 3.7 T–24.5 T SMFs(up to ~54%). It is interesting that the effects are more dependent on MF gradient than intensities, and for the same gradient and intensity, mice responded differently to hypogravity and hypergravity conditions. Therefore, our study not only demonstrated the safeness of high SMFs up to 24.5 T on mice but also revealed their anti-tumor potentials in the future. 展开更多
关键词 static magnetic field (SMF) high magnetic field (MF) TUMOR magnetic field gradient
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A study on the rare earth ore containing scandium by high gradient magnetic separation 被引量:8
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作者 高利坤 陈云 《Journal of Rare Earths》 SCIE EI CAS CSCD 2010年第4期622-626,共5页
Scandium (Sc) concentration from the rare earth ore by high gradient magnetic separation (HGMS) was determined on the basis of Sc content, geophysical parameter determination and the magnetic analyses of the ore. Base... Scandium (Sc) concentration from the rare earth ore by high gradient magnetic separation (HGMS) was determined on the basis of Sc content, geophysical parameter determination and the magnetic analyses of the ore. Based on the condition experiments, expanding experiments were carried out. The results showed that the ore had a Sc grade of 48.90 g/t, and after removing iron by low-intensity magnetic separation, a Sc concentrate of 314.89 g/t grade and with 77.53% recovery was obtained by one-stage roughing-one... 展开更多
关键词 SCANDIUM high gradient magnetic separation rare earths
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