Статті в журналах: "Relative magnetic permeability"

1

Zhou, Sui Hua, Zhi Yi Chen, and Shi Min Feng. "Improvement Methods of Apparent Permeability of Ferromagnetic Core." Advanced Materials Research 712-715 (June 2013): 1876–80. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.1876.

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The performance of induction coil magnetic sensors , which usually have large dimensions and heavy weights, is mainly decided by apparent permeability of the core. But flux concentrator is a effective equipment to improve apparent permeability of the core, which will hardly increase dimensions and weights of magnetic sensors. Firstly, mathematical equations of apparent permeability are explained and influencing factors are analysed. Then influencing degrees of different parameters of the flux concentrator are simulated by Maxwell 2D/3D. The results are shown as follows. (a) The larger diameter and thickness of the flux concentrator, the better is the effect of magnetic concentration. (b) The less the gap between core and concentrator, the better is the effect of magnetic concentration. (c) The larger relative permeability of the flux concentrator, the effect of magnetic concentration is unconspicuous for the material whose relative permeabilityis larger than ten thousands.

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2

Katoh, Tetsuo, Hiroki Takase, and Yasushi Ohshima. "Relative Permeability of Iron-Chromium Magnetic Alloys in Alternating Magnetic Field." DENKI-SEIKO[ELECTRIC FURNACE STEEL] 64, no. 4 (1993): 252–59. http://dx.doi.org/10.4262/denkiseiko.64.252.

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3

Bastola, Anil K., Milan Paudel, and Lin Li. "Magnetic circuit analysis to obtain the magnetic permeability of magnetorheological elastomers." Journal of Intelligent Material Systems and Structures 29, no. 14 (June 27, 2018): 2946–53. http://dx.doi.org/10.1177/1045389x18781046.

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The magnetic permeability of magnetorheological elastomers must be known for their long-term use in the actual engineering systems. In this article, the magnetic permeability of both isotropic and anisotropic magnetorheological elastomers has been determined using a new method. The magnetic induction was measured and a closed magnetic circuit analysis was carried out to obtain the magnetic permeability of magnetorheological elastomers for both isotropic and anisotropic magnetorheological elastomers with 10%–50% volume concentration of carbonyl iron particles. The magnetic permeability was increased with increasing particle concentration for both isotropic and anisotropic magnetorheological elastomers as we could expect. The isotropic permeability is always lower than the anisotropic permeability. The maximum relative permeability value of 6.6 was obtained for 50% particle volume concentration. The experimental results also show a good agreement with theoretical predictions and previous investigations.

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4

Ding, Chao, Yunhui Mei, Khai D. T. Ngo, and Guoquan Lu. "A (Permalloy + NiZn Ferrite) Moldable Magnetic Composite for Heterogeneous Integration of Power Electronics." Materials 12, no. 12 (June 22, 2019): 1999. http://dx.doi.org/10.3390/ma12121999.

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Soft magnetic moldable composites (SM2Cs) would be ideally suited for the integration of magnetic components in power electronic converters because they can be formed into magnetic cores by low-temperature and pressure-less processing. However, most SM2Cs have low relative magnetic permeability, typically less than 30, and high core-loss densities at switching frequencies over 1 MHz. To improve their magnetic properties, we combine powders of Permalloy and a NiZn ferrite with an acrylic polymer to formulate a paste of SM2C. The paste can be molded and then cured below 200 °C without pressure to form cores with a relative permeability over 35 and a core-loss density at 1 MHz, 30% lower than those of commercial cores. The ease of its processing and high-performance properties makes the SM2C a good candidate material for the integration of power magnetics.

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5

Li, Xiao Yang, and Zan Dong Han. "Effect of Uniaxial Stress on Magnetic Permeability and Magnetic Loss of Low-Carbon Steel in Weak Alternating Magnetic Field." Applied Mechanics and Materials 678 (October 2014): 220–27. http://dx.doi.org/10.4028/www.scientific.net/amm.678.220.

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The inverse magnetostrictive effect provides a chance to detect the stress by measuring some magnetic parameters. So it is important to learn the effect of stress on some magnetic parameters. A measuring system to measure magnetic permeability and magnetic loss and a device to load uniaxial tension and pressure stress were developed. The result shows that magnetic permeability and magnetic loss increase with uniaxial tension stress increase and decreases with uniaxial pressure stress increase. It is also concluded that the relative change of magnetic permeability and magnetic loss decrease with increase of the included angle between the directions of the stress and magnetic field. These results suggest that magnetic permeability and magnetic loss can be further used to evaluate the stress in low-carbon steel.

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6

Khadka, Chandra Bahadur. "Relative Nature of Electric Permittivity and Magnetic Permeability of Electromagnetic Wave." Indian Journal of Advanced Physics 1, no. 3 (April 30, 2022): 17–25. http://dx.doi.org/10.54105/ijap.c1021.041322.

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This research is about the special theory of relativity on electric permittivity and magnetic permeability of electromagnetic wave. For this, Four Maxwell's electromagnetic equations play an important role. James Clerk Maxwell suggested that the light travel as electromagnetic wave which require no material medium for propagation. The speed of light (C) in free space is always constant and is independent of the speed of source or observer or the relative motion of the inertial system and has velocity 'C' given by . So velocity of electromagnetic waves depend on obsolute magnetic permeability and obsolute electric permittivity of free space. These two physical quantities rely on relative motion of inertial system. So are not obsolute quantity but are dependent upon the relative motion between the observer and the phenomenon observed. Electric and magnetic field of a charge rely upon the value of obsolute electric permittivity of medium. Concisely, are variant quantity. Consequently electric and magnetic field get relative for electromagnetic wave. That is electric and magnetic field depend on relative motion of inertial system for electromagnetic waves.

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7

Володько, А. В., С. М. Фёдоров, Е. А. Ищенко, М. А. Сиваш, Л. В. Сопина, and А. В. Бунина. "MINIMIZING THE EFFECTIVE AREA OF SCATTERING BY MEANS OF CHANGING THE RELATIVE MAGNETIC PERMEABILITY." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 1 (April 19, 2021): 85–88. http://dx.doi.org/10.36622/vstu.2021.17.1.013.

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Исследуется зависимость эффективной площади рассеяния (ЭПР) от относительной магнитной проницаемости материала, из которого изготавливается структура. В качестве тела моделирования был выбран шар, который изготовлен из диэлектрического материала, у которого возможно выполнять изменение относительной магнитной проницаемости. По полученным результатам моделирования построены графики зависимости максимального значения моностатической ЭПР от частоты, а также от относительной магнитной проницаемости среды. Было показано, что с увеличением относительной магнитной проницаемости материала изготовления происходит увеличение значения ЭПР объекта, а также обнаружена зависимость эффективной площади рассеяния от соотношения размеров шара и длиной волны, так при превышении порогового значения, после которого шар становится крупным объектом, ЭПР резко возрастает. По результатам исследования был построен график зависимости эффективной площади рассеяния шара от относительной магнитной проницаемости материала изготовления. Доказана возможность применения материала с частотозависимой относительной магнитной проницаемостью в качестве стелс-покрытия. В статье содержится исследуемая модель, графики полученных результатов, по которым можно легко определить зависимость ЭПР от частоты и от относительной магнитной проницаемости материала изготовления The article investigates the dependence of the effective scattering area (ESA) on the relative magnetic permeability of the material from which the structure is made. We chose a sphere as the modeling body, which is made of a dielectric material, in which it is possible to change the relative magnetic permeability. Based on the obtained simulation results, graphs of the dependence of the maximum value of monostatic ESA on frequency, as well as on the relative magnetic permeability of the medium, were constructed. It was shown that with an increase in the relative magnetic permeability of the material of manufacture, an increase in the value of the ESA of the object occurs, and the dependence of the effective scattering area on the ratio of the size of the ball and the wavelength was found, so when the threshold value is exceeded, after which the ball becomes a large object, ESA rises sharply. Based on the results of the study, a graph of the dependence of the effective scattering area of the sphere on the relative magnetic permeability of the material of manufacture was built. The possibility of using a material with a frequency-dependent relative magnetic permeability as a stealth coating was proven. The article contains the investigated model, graphs of the results obtained, by which it is easy to determine the dependence of the ESA on the frequency and on the relative magnetic permeability of the material of manufacture

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8

Sandulyak, Alexander V., Roman Y. Tkachenko, Darya A. Sandulyak, Maria N. Polismakova, Anna A. Sandulyak, and Vera A. Ershova. "Analysis of dependence between magnetic properties of granulated ferromagnetic specimens and relation of its length to diameter." Izmeritel`naya Tekhnika, no. 6 (2020): 46–51. http://dx.doi.org/10.32446/0368-1025it.2020-6-46-51.

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Paper studies the problems about experimental determining magnetic parameters of nonuniform granular magnetics. It has been noted that the existing shortage of direct and (or) indirect experimental data on the magnetic properties of granular ferromagnetic specimens with different values of a relative length, in particular, has a negative impact on the validity of the requirements and decisions to create and ensure the performance of relevant functional elements, movable operating elements of various equipments and devices. By the example of cylindrical specimens of balls with the range of relative length 1–16 within the framework of effective medium macromodel the dependences of induction, magnetic permeability, susceptibility, magnetization and field intensity have been obtained. It has been shown that in the range of field intensity 9–47 kA/m values of induction and magnetization of investigating specimens increase, that indicates the absence of magnetic saturation of such granular (as opposed to solid) magnetics. And this is the case at almost stable values of magnetic susceptibility and permeability. Obtained results are useful in designing movable operating elements of various equipments and devices.

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9

Xue, Kaihua, Lei Yang, Jiafei Zhao, Yanghui Li, Yongchen Song, and Shan Yao. "The Study of Flow Characteristics During the Decomposition Process in Hydrate-Bearing Porous Media Using Magnetic Resonance Imaging." Energies 12, no. 9 (May 8, 2019): 1736. http://dx.doi.org/10.3390/en12091736.

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The flow characteristics during decomposition of hydrate-bearing sediments are the most critical parameters for the gas recovery potential from natural gas hydrate reservoirs. The absolute and relative permeability and the flow field distribution during the decomposition process of hydrate-bearing porous media synthetically created by glass beads are in-situ measured by using magnetic resonance imaging. The absolute permeability value increased slowly, then became stable after the decomposition amount was 50%. The relative permeability change curve is a typical X-shaped cross curve. As the hydrate decomposed, the relative permeability values of the two phases increased, the range of the two-phase co-infiltration zone increased with the increase of relative permeability at the endpoint, and the coexistence water saturation decreased. At the beginning of the decomposition, (hydrate content 100% to 70%), the relative permeability of methane and water rose rapidly from 22% to 51% and from 58% to 70%, respectively. When the amount of the remaining hydrate was less than 50%, the relative permeability curve of the hydrate-bearing glass beads almost kept unchanged. During the hydrate decomposition process, the velocity distribution was very uneven and coincided with the porous media structure.

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10

Sandulyak, Alexander, Anna Sandulyak, and Petr Shkatov. "Dependence of Granular Matrix Demagnetizing Factor on the Matrix Relative Size." Advanced Materials Research 1083 (January 2015): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1083.32.

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We note that for a wide range of porous, especially granular, ferromagnetics used as matrices of magnetic filter-separators, there is still an issue of defining their demagnetizing factor N which has a dramatic effect on the values of average magnetic permeability of these operating units of filter-separators. The work aims at filling the existent gaps in the issue, we supply N values depending on the relative size of such magnets as well as a respective generalizing phenomenological dependence which is characterized by an exponential realtion between the demagnetizing factor and relative size radical. The established relation allows obtaining real values of magnetic permeability of a short filter matrix thus providing an unbiased comparative estimate of its technological workability.

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11

Bi, Yu, Xiao Ming Zhang, and Wan Jun Wang. "Design Study of Trapezoid-Shaped Magnetic Flux Concentrator for Axial Amplification Characteristics." Applied Mechanics and Materials 875 (January 2018): 77–83. http://dx.doi.org/10.4028/www.scientific.net/amm.875.77.

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In this paper, the axial magnetic field amplification characteristics of the trapezoid-shaped magnetic flux concentrator at micrometer scale are studied. The factors of the dimension parameters including the ratio of the outer and inner width, the aspect ratio, the air gap, as well as the material property including the relative permeability influencing on the magnetic gain are analyzed using the finite element method. It indicates that the concentrator with air gap shows obvious magnetic amplification. The concentrator shows intensive magnetic gain with the increasing ratio of the outer and inner width, aspect ratio and the decreasing air gap. When the dimension parameters of the length, the outer width, the inner width, and the air gap are of 1000um, 200um, 10um, and 5um respectively, the magnetic gain of 65 is obtained. Additionally, the magnetic gain increases with the relative permeability of the concentrator. When the relative permeability reaches a certain value, the magnetic gain tends to saturation. The magnetic flux concentrator has a linear working range of 12.8mT. The study can provide a theoretical reference for the design and application of the trapezoid-shaped magnetic flux concentrator.

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12

Knight, J. D., Z. Xia, E. McCaul, and H. Hacker. "Determination of Forces in a Magnetic Bearing Actuator: Numerical Computation With Comparison to Experiment." Journal of Tribology 114, no. 4 (October 1, 1992): 796–801. http://dx.doi.org/10.1115/1.2920951.

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Calculations of the forces exerted on a journal by a magnetic bearing actuator are presented, along with comparisons to experimentally measured forces. The calculations are based on two-dimensional solutions for the flux distribution in the metal parts and free space, using finite but constant permeability in the metals. Above a relative permeability of 104 the effects of changes in permeability are negligible, but below 104 decreases in permeability cause significant decreases in the force. The calculated forces are shown to depend on the metal permeability more strongly when the journal is displaced from its centered position. The predicted forces in the principal attractive direction are in good agreement with experiment when a relatively low value of permeability is chosen. The forces measured normal to the axis of symmetry when the journal is displaced from that axis, however, are significantly higher than predicted by theory, even with a value of relative permeability larger than 5000. These results indicate a need for futher work including nonlinear permeability distributions.

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13

Li, Qiang, Zuo Bin Yuan, Yong Ming Yang, and Cheng Hu. "The Simulated Calculation of the First Order Buoyancy Force under Different Relative Permeability of Ferrofluid." Applied Mechanics and Materials 303-306 (February 2013): 22–25. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.22.

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In this paper, the first order buoyancy force of ferrofluid is simulated calculation under external magnetic field in ferrofluid devices. The relationship between first order buoyancy force and displacement of nonmagnetic body under different relative permeability of ferrofluid，and the relationship between first order buoyancy force and relative permeability of ferrofluid are obtained.

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14

Diguet, Gildas, Gaël Sebald, Masami Nakano, Mickaël Lallart, and Jean-Yves Cavaillé. "Magnetic behavior of magneto-rheological foam under uniaxial compression strain." Smart Materials and Structures 31, no. 2 (December 27, 2021): 025018. http://dx.doi.org/10.1088/1361-665x/ac3fc8.

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Abstract This study reports the development of a magneto-rheological foam, which consists in a porous matrix filled by ferromagnetic particles. The porous matrix of such a composite being easily deformable, large magnetic properties changes are expected. The measurements of the magnetic properties of such a magneto-rheological foam submitted to a compressive strain are reported. Main aspect of the magnetic properties is the low field magnetic permeability as the function of the compression and filling factor. Then, larger field magnetization measurement allowed to investigate the saturation field as a function of the filling factor. Because of the large amount of pores in the material, the magnetic relative permeability, µ r, is quite small (µ r ∼ 1). However, these materials can be easily deformed over a large range of strain providing important relative variation of the magnetic properties under mechanical solicitation. The composite magnetic permeability is increasing under compression for all the considered filling factors. A model is then developed to understand the variation of the permeability with the strain. Hence, from a simple concept consisting of taking advantage of high deformation of foams, the present study demonstrates the interest of such a highly compressible while cheap composite for obtaining a large magneto-rheological effect.

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15

Tsepelev, Vladimir. "Nanocrystalline Soft Magnetic Toroidal Cores of the Highest Relative Magnetic Permeability and Low Coercive Force." Advanced Materials Research 716 (July 2013): 276–80. http://dx.doi.org/10.4028/www.scientific.net/amr.716.276.

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All the technologies of the melt quenching preparation ensure its time-temperature treatment to not only improve but also stabilize the metal structure and properties with every melt. The influence of annealing temperature of nanocrystalline alloy Fe72.5Cu1Nb2Mo1.5Si14B9 on the structure and magnetic properties has been investigated. The relation between numerical values of the coercive force, the initial magnetic permeability and the magnetic hysteresis loop rectangularity factor allows optimizing a mode of nanocrystalline alloy heat treatment.

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16

Yan, Jin, Rongchen Zheng, Peng Chen, Shuping Wang, and Yunqing Shi. "Calculation Model of Relative Permeability in Tight Sandstone Gas Reservoir with Stress Sensitivity." Geofluids 2021 (December 10, 2021): 1–12. http://dx.doi.org/10.1155/2021/6260663.

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During the development of tight gas reservoir, the irreducible water saturation, rock permeability, and relative permeability change with formation pressure, which has a significant impact on well production. Based on capillary bundle model and fractal theory, the irreducible water saturation model, permeability model, and relative permeability model are constructed considering the influence of water film and stress sensitivity at the same time. The accuracy of this model is verified by results of nuclear magnetic experiment and comparison with previous models. The effects of some factors on irreducible water saturation, permeability, and relative permeability curves are discussed. The results show that the stress sensitivity will obviously reduce the formation permeability and increase the irreducible water saturation, and the existence of water film will reduce the permeability of gas phase. The increase of elastic modulus weakens the stress sensitivity of reservoir. The irreducible water saturation increases, and the relative permeability curve changes little with the increase of effective stress. When the minimum pore radius is constant, the ratio of maximum pore radius to minimum pore radius increases, the permeability increases, the irreducible water saturation decreases obviously, and the two-phase flow interval of relative permeability curve increases. When the displacement pressure increases, the irreducible water saturation decreases, and the interval of two-phase flow increases. These models can calculate the irreducible water saturation, permeability and relative permeability curves under any pressure in the development of tight gas reservoir. The findings of this study can help for better understanding of the productivity evaluation and performance prediction of tight sandstone gas reservoirs.

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17

Maricic, A., M. Spasojevic, S. Arnaut, D. Minic, and M. M. Ristic. "The effect of structural changes on magnetic permeability of amorphous powder Ni80Co20." Science of Sintering 40, no. 3 (2008): 303–9. http://dx.doi.org/10.2298/sos0803303m.

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The structural changes of Ni80Co20 amorphous powder were tested during heating. The alloy was obtained by electrolysis from ammonia solution sulfate of cobalt and nickel on the titanium cathode. The differential scanning calorimetry (DSC) method was used to detect that the crystallization process of powder occurred in two stages with crystallization peaks temperatures of the first stage at 690 K and of the second stage at 790 K. The effect of structural relaxation and crystallization of powder on magnetic properties was predicted by measurement of the relative magnetic permeability change in isothermal and nonisothermal conditions. On the basis of the time change of relative magnetic permeability at a defined temperature in the temperature range of the first and second crystallization peak on the thermogram, the kinetics of crystallization was defined. It was predicted, that in the initial time interval, in the range of the first crystallization peak, the rate of crystallization is determined by the rate of nucleation of the amorphous part of the powder. However, in the second time interval, the crystallization rate is determined by the rate of diffusion. In the range of the second peak, in the beginning the rate of crystal growth is determined by activation energy of the atom pass from smaller to bigger crystal grain. In second time interval, the rate of crystal grain growth is determined by the diffusion rate of atoms to the location of integration into bigger crystal grains. For all processes which determine the rate of crystallization in temperature ranges of both crystallization peaks, the Arrhenius temperature dependence of rate for those processes is obtained. The relative magnetic permeability of crystallized powder at 873 K, is smaller for about 30 % than the relative magnetic permeability of fresh powder at room temperature. However, structurally relaxed powder at 573 K has an about 22 % larger magnetic permeability than the same fresh powder at room temperature.

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18

Neto, K. Skeff, A. F. Bakuzis, P. C. Morais, A. R. Pereira, R. B. Azevedo, L. M. Lacava, and Z. G. M. Lacava. "The influence of aggregates and relative permeability on the magnetic birefringence in ionic magnetic fluids." Journal of Applied Physics 89, no. 6 (March 15, 2001): 3362–69. http://dx.doi.org/10.1063/1.1345867.

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19

Ahmad, Abid, Bhagyashree Mishra, Andrew Foley, Leslie Wood, and Maggie Yihong Chen. "High Permeability Photosintered Strontium Ferrite Flexible Thin Films." Micromachines 12, no. 1 (January 1, 2021): 42. http://dx.doi.org/10.3390/mi12010042.

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The paper is focused on the development and optimization of strontium ferrite nanomaterial and photosintered flexible thin films. These magnetic thin films are characterized with direct current (DC) and high frequency measurements. For photosintered strontium ferrite samples, we achieved relative complex permeability of about 29.5-j1.8 and relative complex permittivity of about 12.9-j0.3 at a frequency of 5.9 GHz.

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20

Ayachit, Agasthya, and Marian K. Kazimierczuk. "Sensitivity of effective relative permeability for gapped magnetic cores with fringing effect." IET Circuits, Devices & Systems 11, no. 3 (March 7, 2017): 209–15. http://dx.doi.org/10.1049/iet-cds.2016.0410.

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21

Rovers, J. M. M., J. W. Jansen, and E. A. Lomonova. "Modeling of Relative Permeability of Permanent Magnet Material Using Magnetic Surface Charges." IEEE Transactions on Magnetics 49, no. 6 (June 2013): 2913–19. http://dx.doi.org/10.1109/tmag.2012.2236103.

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22

Long, Haiming, Xiaojie Wu, Yunkun Lu, Haifeng Zhang, and Junjie Hao. "Effect of Polyimide-Phosphating Double Coating and Annealing on the Magnetic Properties of Fe-Si-Cr SMCs." Materials 15, no. 9 (May 7, 2022): 3350. http://dx.doi.org/10.3390/ma15093350.

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Fe-Si-Cr soft magnetic powder cores (SMCs), with high electrical resistivity, magnetic permeability, saturation magnetic induction, and good corrosion resistance, are widely applied to inductors, filters, choke coils, etc. However, with the development of electronic technology with high frequency and high power density, the relative decline in the magnetic properties limits the high-frequency application of SMCs. In this paper, the phosphating process and polyimide (PI) insulation coating is applied to Fe-Si-Cr SMCs to reduce the core loss, including hysteresis loss and eddy current loss. The microstructure and composition of Fe-Si-Cr powders were analyzed by SEM, XRD, and Fourier-transform infrared spectra, respectively. The structural characteristics of the Fe-Si-Cr @ phosphate layer @ PI layer core–shell double coating were studied, and the best process parameters were determined through experiments. For SMCs with 0.4 wt% content of PI, the relative permeability is greater than 68%, and the core loss is the lowest, 7086 mW/cm3; annealed at 500 °C, the relative permeability is greater than 57%, and the core loss is the lowest, 6222 mW/cm3. A 0.4 wt% content of PI, annealed at 500 °C, exhibits the ideal magnetic properties: μe = 47 H/m, P = 6222 mW/cm3.

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23

Saleem, Muhammad, and Ali Rizwan. "Development of Application Specific Intelligent Framework for the Optimized Selection of Industrial Grade Magnetic Material." Polymers 13, no. 24 (December 10, 2021): 4328. http://dx.doi.org/10.3390/polym13244328.

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This article attempts to introduce a simple and robust way for the classification of soft magnetic material by using multivariate statistics. The six magnetic properties including coercive magnetic field, relative magnetic permeability, electrical resistivity magnetic inductions, i.e., remanence and saturation along with Curie temperature are used for the classification of 16 soft magnetic materials. Descriptive statistics have been used for defining the prioritization order of the mentioned magnetic characteristics with coercive magnetic field and Curie temperature as the most and least important characteristics for classification of soft magnetic material. Moreover, it has also justified the usage of cluster analysis and principal component analysis for classifying the enlisted materials. After descriptive statistics, cluster analysis is used for classification of materials into four groups, i.e., excellent, good, fair and poor while defining the prioritization order of materials on a relative scale. Principal component analysis reveals that the relative permeability is responsible for defining 99.69% of total variance and is also negatively correlated with the coercive magnetic field. Therefore, these two characteristics are considered the responsible factors for categorically placing the enlisted materials into four clusters. Furthermore, principal component analysis also helps in figuring out the fact that a combined influential consequence of relative permeability, coercive magnetic field, electrical resistivity and critical temperature are responsible for defining prioritization ordering of materials within the clusters. The material’s suitability index is identified while making use of adjacency and decision matrices obtained from material assessment graph and relative importance of magnetic properties, respectively. Afterward this material suitability index is used to rank the enlisted materials based on selected attributes. According to the suitability index, the best choice among enlisted soft magnetic materials is Supermalloy, Magnifer 7904 which is present in group 1 labeled as excellent by multivariate analysis. Therefore, the results of graph theory are in accordance with cluster analysis and principal component analysis, thus confirming the potential of this intelligent approach for the selection application specific magnetic materials.

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Sandulyak, Anna, Alexander Sandulyak, Dmitry V. Oreshkin, and Marina Popova. "Applied Model of Magnetization of a Granulated Material." Applied Mechanics and Materials 467 (December 2013): 76–80. http://dx.doi.org/10.4028/www.scientific.net/amm.467.76.

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Results of researches (of magnetic permeability) of elementary effective magnetic channel in porous (granulated) material are given. Such results permit to calculate a relative intensity of field between the grains.

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25

Beard, Les P., and Jonathan E. Nyquist. "Simultaneous inversion of airborne electromagnetic data for resistivity and magnetic permeability." GEOPHYSICS 63, no. 5 (September 1998): 1556–64. http://dx.doi.org/10.1190/1.1444452.

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Where the magnetic permeability of rock or soil exceeds that of free space, the effect on airborne electromagnetic systems is to produce a frequency‐independent shift in the in‐phase response of the system while altering the quadrature response only slightly. The magnitude of the in‐phase shift increases as (1) the relative magnetic permeability is increased, (2) the amount of magnetic material is increased, and (3) the airborne sensor gets nearer the earth’s surface. Over resistive, magnetic ground, the shift may be evinced by negative in‐phase measurements at low frequencies; but over more conductive ground, the same shift may go unnoticed because of the large positive in‐phase response. If the airborne sensor is flown at low levels, the magnitude of the shift may be large enough to affect automatic inversion routines that do not take this shift into account, producing inaccurate estimated resistivities, usually overestimates. However, layered‐earth inversion algorithms that incorporate magnetic permeability as an additional inversion parameter may improve the resistivity estimates. We demonstrate this improvement using data collected over hazardous waste sites near Oak Ridge, Tennessee, USA. Using resistivity inversion without magnetic permeability, the waste sites are almost invisible to the sensors. When magnetic permeability is included as an inversion parameter, the sites are detected, both by improved resistivity estimates and by estimated magnetic permeability.

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Saafan, S. A., T. M. Meaz, and E. H. El-Ghazzawy. "Study of DC conductivity and relative magnetic permeability of nanoparticle NiZnFe2O4/PPy composites." Journal of Magnetism and Magnetic Materials 323, no. 11 (June 2011): 1517–24. http://dx.doi.org/10.1016/j.jmmm.2011.01.010.

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A. Y. Rojeab, W. Hosny. "Power Loss and Relative Permeability of Annealed Amorphous Magnetic Cores for Electrical Machines." Electric Power Components and Systems 29, no. 6 (June 2001): 555–64. http://dx.doi.org/10.1080/153250001300338781.

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Fiske, Thomas J., Halit Gokturk, and Dilhan M. Kalyon. "Enhancement of the relative magnetic permeability of polymeric composites with hybrid particulate fillers." Journal of Applied Polymer Science 65, no. 7 (August 15, 1997): 1371–77. http://dx.doi.org/10.1002/(sici)1097-4628(19970815)65:7<1371::aid-app15>3.0.co;2-y.

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29

Du, Jin-Hong, Chao Sun, Shuo Bai, Ge Su, Zhe Ying, and Hui-Ming Cheng. "Microwave Electromagnetic Characteristics of a Microcoiled Carbon Fibers/paraffin Wax Composite in Ku Band." Journal of Materials Research 17, no. 5 (May 2002): 1232–36. http://dx.doi.org/10.1557/jmr.2002.0182.

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The complex relative permittivity ∈γ and permeability μγ of microcoiled carbon fibers (MCCFs) imbedded in paraffin wax were measured at Ku band frequencies (12.4–18 GHz). Both the real and imaginary parts of the complex relative permittivity of the MCCFs/paraffin wax composite decreased with increase of the frequency. The real part of the complex relative permeability of the composite increases with increase of the frequency, and the imaginary part is nonzero and nearly constant over the measured frequency range. The dielectric loss tangent (tan δ∈), the magnetic loss tangent (tan δm), and amplitude attenuation factor (α) were determined as well. On the basis of the experimental results, the MCCFs/paraffin wax composite is mainly a kind of dielectric lossy material with small magnetic loss and diamagnetism in the Ku band.

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30

Birčáková, Zuzana, Peter Kollár, Bernd Weidenfeller, Ján Füzer, Radovan Bureš, and Mária Fáberová. "Iron Based Soft Magnetic Composite Material Prepared By Injection Molding." Powder Metallurgy Progress 21, no. 1 (June 1, 2021): 10–17. http://dx.doi.org/10.2478/pmp-2021-0002.

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Abstract Soft magnetic composite materials consisting of FeSi powder and polypropylene were prepared by the injection molding method, with different polypropylene contents of 25, 30 and 35 vol. %. The magnetic and electrical properties as well as the structure of the composites were investigated. The samples exhibited very low porosity, high electrical resistivity, relatively low coercivity, sufficient saturation magnetic flux density and permeability, and high resonant frequency. FeSi particles were found to be well insulated from each other and homogeneously dispersed in the polymer matrix of the composite. The observed isotropic structure was confirmed by the fitting of the experimental dependence with the analytical expression of the reversible relative permeability vs. magnetic flux density.

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31

Guo, Yuhang, Baozhi Pan, and Lihua Zhang. "A New Method to Identify Reservoirs in Tight Sandstones Based on the New Model of Transverse Relaxation Time and Relative Permeability." Geofluids 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6787038.

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Relative permeability and transverse relaxation time are both important physical parameters of rock physics. In this paper, a new transformation model between the transverse relaxation time and the wetting phase’s relative permeability is established. The data shows that the cores in the northwest of China have continuous fractal dimension characteristics, and great differences existed in the different pore size scales. Therefore, a piece-wise method is used to calculate the fractal dimension in our transformation model. The transformation results are found to be quite consistent with the relative permeability curve of the laboratory measurements. Based on this new model, we put forward a new method to identify reservoir in tight sandstone reservoir. We focus on the Well M in the northwestern China. Nuclear magnetic resonance (NMR) logging is used to obtain the point-by-point relative permeability curve. In addition, we identify the gas and water layers based on new T2-Kr model and the results showed our new method is feasible. In the case of the price of crude oil being low, this method can save time and reduce the cost.

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Jafri, A. D. Ulfat, and Akhlesh Lakhtakia. "Light scattering by magnetoelectrically gyrotropic sphere with unit relative permittivity and relative permeability." Journal of the Optical Society of America A 31, no. 11 (October 20, 2014): 2489. http://dx.doi.org/10.1364/josaa.31.002489.

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33

Pesic, O., M. Spasojevic, B. Jordovic, P. Spasojevic, and A. Maricic. "Effect of electrodeposition current density on the microstructure and magnetic properties of nickel-cobalt-molybdenum alloy powders." Science of Sintering 46, no. 1 (2014): 117–27. http://dx.doi.org/10.2298/sos1401117p.

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Nanostructured nickel-cobalt-molybdenum alloy powders were electrodeposited from an ammonium sulfate bath. The powders mostly consist of an amorphous phase and a very small amount of nanocrystals with an mean size of less than 3 nm. An increase in deposition current density increases the amorphous phase percentage, the density of chaotically distributed dislocations and internal microstrains in the powders, while decreasing the mean nanocrystal size. The temperature range over which the structural relaxation of the powders deposited at higher current densities occurs is shifted towards lower temperatures. A change in relative magnetic permeability during structural relaxation is higher in powders deposited at higher current densities. Powder crystallization takes place at temperatures above 700?C. The formation of the stable crystal structure causes a decrease in relative magnetic permeability.

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Paltanea, Gheorghe, Veronica Manescu Paltanea, Iosif Vasile Nemoianu, and Horia Gavrila. "Non-Oriented Silicon Iron Alloys Used in Efficient Electrical Motor Production." Key Engineering Materials 821 (September 2019): 229–36. http://dx.doi.org/10.4028/www.scientific.net/kem.821.229.

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In this paper four non-oriented electrical steel grades M400-50A, M400-65A, M300-35A and NO20, utilizing a laboratory single sheet tester, were analyzed. For the magnetic measurements the peak magnetic polarization of 1 T was chosen. The frequency was variated between 3 Hz and 400 Hz. The isotropic electrical steel sheets were cut through punching technology, along the rolling direction. The experimentally determined energy losses were decomposed, using the loss separation theory, into hysteresis, classical and excess components. The relative magnetic permeability was analyzed and its parts, real and imaginary permeability were computed. The non-oriented alloy magnetic properties’ variation as a function of frequency was plotted and explained in the paper.

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35

Yap, Yun Kee, Pei Ching Oh та Evan Yew Jin Chin. "Development of αFe2O3-TiO2/PPOdm Mixed Matrix Membrane for CO2/CH4 Separation". E3S Web of Conferences 287 (2021): 02013. http://dx.doi.org/10.1051/e3sconf/202128702013.

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Magnetophoretic dispersion of magnetic fillers has been proven to improve gas separation performances of mixed matrix membrane (MMM). However, the magnetic field induced is usually in a horizontal or vertical direction during membrane casting. Limited study has been conducted on the effects of rotational magnetic field direction towards dispersion of particles. Thus, this work focuses on the rearrangement of paramagnetic iron oxide-titanium dioxide (αFe2O3-TiO2) nanocomposite in poly (2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membrane via rotational magnetic field to investigate the dispersion of filler and effects towards its overall gas separation performance. The paramagnetic fillers were incorporated into polymer via dry phase inversion method at different weight loading. MMM with 3 wt% loading shows the best performance in terms of particle dispersion and gas separation performance. It shows the greatest relative particles count and least agglomerates via OLYMPUS™ Stream software with image taken by optical microscope. Relative to pristine membrane, it displays a permeability and selectivity increment of 312% and 71%. MMM with 3 wt% loading was refabricated in the presence of rotational magnetic field to enhance the dispersion of paramagnetic fillers. Results display an increment of selectivity by 8% and CO2 permeability by 46% relative to unmagnetised MMM of 3 wt% loading.

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36

Chute, F. S., and F. E. Vermeulen. "A simple method for determining electrical resistivity and relative magnetic permeability of steel tubulars." Canadian Journal of Electrical and Computer Engineering 16, no. 4 (October 1991): 154–56. http://dx.doi.org/10.1109/cjece.1991.6591705.

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37

TASHIRO, Kunihisa, Hiroyuki WAKIWAKA, Ryo NAKANO, Takanori IGARASHI, Tomohito ISHIKAWA, and Akihiro MAKINO. "Evaluation of relative permeability and magnetic shielding performance of Glassy alloy varying in composition." Journal of the Japan Society of Applied Electromagnetics and Mechanics 23, no. 2 (2015): 356–61. http://dx.doi.org/10.14243/jsaem.23.356.

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38

Xiao, Zhuohao, Chuanhu Wang, Lie Liu, Zhihong Yang, and Ling Bing Kong. "Optimization of Ni0.95−xZnxCo0.05Fe1.90Mn0.02O4 ceramics with promising magneto-dielectric properties for VHF antenna miniaturization." Journal of Advanced Dielectrics 08, no. 01 (February 2018): 1850001. http://dx.doi.org/10.1142/s2010135x18500017.

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Magnetic, dielectric and DC conductive properties of Ni[Formula: see text]ZnxCo[Formula: see text]Fe[Formula: see text]Mn[Formula: see text]O4 (with [Formula: see text]-0.20 at an interval of 0.05) ferrite ceramics were studied, in order to develop magneto-dielectric materials with almost equal values of relative permeability and permittivity, for the miniaturization of HF (3–30[Formula: see text]MHz) and VHF (30–90[Formula: see text]MHz and 100–300[Formula: see text]MHz) antennas. The ferrite ceramics were prepared by using the conventional two-step sintering process. The real part of relative permeability is increased almost linearly with increasing concentration of Zn, while that of relative permittivity keeps nearly unchanged. It is found that promising magneto-dielectric materials, with close values of real permeability and permittivity over 30–90 MHz (VHF), can be obtained for the samples at Zn concentrations between [Formula: see text] and [Formula: see text].

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39

Milutinov, Miodrag, Maria Nikolic, Snezana Lukovic, Nelu Blaz, Nebojsa Labus, Obrad Aleksic, and Ljiljana Zivanov. "Influence of starting powder milling on magnetic properties of Mn-Zn ferrite." Processing and Application of Ceramics 11, no. 2 (2017): 160–69. http://dx.doi.org/10.2298/pac1702160m.

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In this paper, the influence of additional sieving and milling of starting industrial Mn-Zn powders on magnetic properties was investigated. The starting powder was milled for 60 minutes, followed by sieving through 325 and 400 meshes. The starting and milled powders were used to fabricate toroid shaped samples sintered at 1200?C for 2 hours. Structural parameters of the fabricated samples were analysed by X-ray diffraction and scanning electron microscopy. Complex permeability, core loss density, and hysteresis were measured using the modified watt-meter method. The complex permeability and hysteresis loop were modelled with a new model proposed in the paper. The core loss density was modelled with the Steinmetz empirical equation. The experimental results and calculations show the significance of the additional milling and sieving process on magnetic properties of Mn-Zn ferrite in the frequency range 0.1-10MHz. These processes increase the relative permeability about 3 times and decrease the core loss 4 times by milling of the starting powder.

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40

Qu, Yun Peng, Pei Tao Xie, Yao Liu, Yong Wang, Run Hua Fan, Yu Lin Wu, and Yuan Tian. "High Frequency Electrical and Magnetic Properties of Al/Epoxy Composites Prepared by Insulation Coating Process." Materials Science Forum 898 (June 2017): 1770–75. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1770.

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Al/Epoxy composites with different Al content were prepared by insulation coating process including high energy ball milling and hot press. The electrical properties and magnetic performance including ac conductivity, permittivity, reactance and permeability were investigated in detail. The frequency dispersions of ac conductivity followed the power law, indicating the hopping conduction behavior. The real part of permittivity for composites increased with higher Al content, which was attributed to the more interface between Al and epoxy. Besides, the real part of the relative permeability decreased with higher Al content in high frequency.

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41

Ziolkowski, Marcin, and Stanislaw Gratkowski. "Shielding from external magnetic fields by rotating magnetic conducting cylindrical shells." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, no. 2 (March 2, 2015): 505–13. http://dx.doi.org/10.1108/compel-08-2014-0209.

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Purpose – In many different engineering fields often there is a need to protect regions from electromagnetic interference. According to static and low-frequency magnetic fields the common strategy bases on using a shield made of conductive or ferromagnetic material. Another screening technique uses solenoids that generate an opposite magnetic field to the external one. The purpose of this paper is to discuss the shielding effect for a magnetic and conducting cylindrical screen rotating in an external static magnetic field. Design/methodology/approach – The magnetic flux density is expressed in terms of the magnetic vector potential. Applying the separation of variables method analytical solutions are obtained for an infinitely long magnetic conducting cylindrical screen rotating in a uniform static transverse magnetic field. Findings – Analytical formulas of the shielding factor for a cylindrical screen of arbitrary conductivity and magnetic permeability are given. A magnetic Reynolds number is found to be an appropriate indication of the change in magnetic field inside the screen. Useful simplified expressions are presented. Originality/value – This paper treats in a qualitative way the possibility of static magnetic field shielding by using rotating conducting magnetic cylindrical screens. Analytical solutions are given. If the angular velocity is equal to zero or the relative permeability of the shield is equal to one the shielding factor has forms well known from literature.

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42

Li, Chang Sheng, Xin Fang Xu, Biao Ma, Chang Gui Yao, and Min Wang. "Experimental Research on Non-Magnetic Steel 30Mn27Al4V." Advanced Materials Research 479-481 (February 2012): 147–55. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.147.

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Non-magnetic steels are required in energy and transportation fields such as superconducting energy storage equipment, magnetic liquid power generation equipment, superconducting generators, superconducting power transmission and ship electromagnetic propulsion. Experimental research on steel making, hot rolling, solution and aging for non-magnetic steel 30Mn27Al4V was carried out in the laboratory. The microstructure evolution was observed and the mechanical property and relative magnetic permeability were tested after heat treatment. The effects of fine particles such as VC, VN and V(CN) dispersively distributed in austenite matrix on precipitation, grain refinement and austenitic nucleation were analyzed. The microstructure of the tested steel is austenite. The grain size is 24~28μm. At room temperature, the yield strength and tension strength are 556 MPa and 701 MPa, elongation after fracture of the steel is 47%, the yield ratio is 0.79, strength and ductility product is 32.9 GPa%. After solution and aging treatment, the steel shows a yield strength of 325~371 MPa, tension strength of 550~645 MPa, elongation of 58~78 %, a yield ratio of 0.54~0.60, strength and ductility product of 36.3~46.3 GPa%. The relative magnetic permeability is below 1.005. The results indicate that the tested steel exhibits good mechanical property and non-magnetism. It has no elements of Ni and Cr, so it just needs simple process flow and lower production cost. The numerous applications of the steel in industry can create great economic benefits.

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43

Zhong, Haisheng, Qiang Li, Zhifeng Zhong, and Ming Cheng. "Magnetic Properties of Ni-Zn Ferrite Ceramics Prepared from the Blend of Powders." Materials Science Forum 475-479 (January 2005): 2193–96. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.2193.

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Ni-Zn ferrite ceramics were prepared from the blend of nano-sized powders and ultra-fine particles at the relative low sintering temperature (≤1200°C). The microstructure of the as-sintered samples characterized by SEM indicated that this process obstructed abnormal grain growth which often appeared in the Ni-Zn ferrite ceramics sintered from the nano-sized powders. The result of VSM measurements showed that the ratio of nano-sized powders to ultra-fine particles effected the initial permeability (μi) of the as-sintered samples. Optimum initial permeability can be obtained by adjusting the ratio as 1:1.

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44

Wu, Feng, Qicheng Fan, Dan Huang, Li Ma, Xiaoyu Liang, and Liqiang Sima. "Predicting gas–water relative permeability using Nuclear Magnetic Resonance and Mercury Injection Capillary Pressure measurements." Journal of Natural Gas Science and Engineering 32 (May 2016): 35–47. http://dx.doi.org/10.1016/j.jngse.2016.04.033.

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45

Satya Deo, Deepak Kumar Maurya, and A. N. Filippov. "Effect of Magnetic Field on Hydrodynamic Permeability of Biporous Membrane Relative to Micropolar Liquid Flow." Colloid Journal 83, no. 6 (November 2021): 662–75. http://dx.doi.org/10.1134/s1061933x21060119.

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46

Zhao, Hong Jie, Ji Zhou, Zhi Lun Gui, and Long Tu Li. "Preparation and Magnetic Properties of Low Temperature Sintering Bi-Substituted Yttrium Iron Garnet." Key Engineering Materials 280-283 (February 2007): 481–84. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.481.

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The low temperature sinterability and magnetic properties of Bi-substituted yttrium iron garnet (YIG) polycrystalline samples were studied in this paper. The results showed that Bi-substitution can lower garnet phase formation temperature from about 1200oC to 900oC and ceramic sintering temperature from over 1300oC to about 1050oC respectively. The Bi-substitution leads to a decrease in initial permeability and an increase in ferromagnetic resonance linewidth (ΔH) of sintered specimens. Saturation magnetization decreases and coercive force increases a few with an increase of Bi content. The mechanism of Bi-substitution on initial permeability and ΔH is discussed. The change in initial permeability of Bi-substituted specimens relative to unsubstituted YIG results from Bismuth volatilization and weakening of superexchange interaction. The lattice dilatation in Bi-substituted YIG gives cause for a decrease of saturation magnetization and an increase of coactivity force.

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47

Chik, Abdullah, Nazli Ahmad Aini, and Haider F. Abdul Amir. "Physical Characteristic of Zn Doped Soft Ferrites M_xZn_1-x Fe₂O₄." Key Engineering Materials 594-595 (December 2013): 39–43. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.39.

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The chemical composition and preparation methods for ferrite were studied in order to control the quality of ferrite such as higher initial permeability and low energy losses. Nine samples of soft ferrite MxZn1-xFe2O4 with M=Ni, Mg, Cu ; x=0.2, 0.3, and 0.4 was prepared using solid state ceramic method and characterized for initial permeability, coercivity and relative loss factor (RLF). Studies show that samples with low Zn concentration, x=0.4, exhibit higher initial permeability, μi, with magnitude highest in sample with Ni concentration, that also has the highest atomic susceptibility among Ni, Mg and Cu. Initial permeability, μi ,also influences the resistivity of the samples with increasing susceptibility of magnetic spins, so samples with higher μi, e.g. Ni0.4Zn0.6Fe2O4 exhibit increased resistivity with increased initial permeability while Cu0.4Zn0.6Fe2O4 exhibit decreasing resistivity with increasing Cu content and lower initial permeability.

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48

Froemel, Joerg, Satoru Akita, and Shuji Tanaka. "Simple Device to Measure Pressure Using the Stress Impedance Effect of Amorphous Soft Magnetic Thin Film." Micromachines 11, no. 7 (June 30, 2020): 649. http://dx.doi.org/10.3390/mi11070649.

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A simple micro-machined pressure sensor, based on the stress-impedance (SI) effect, was fabricated herein using typical micro-fabrication technologies. To sense pressure, a 1-µm thin, soft magnetic metallic film of FeSiB was sputtered and used as a diaphragm. Its electrical response (impedance change) was measured under pressure in a frequency band from 5 to 500 MHz. A lumped-element equivalent electric circuit was used to separate the impedance of the soft magnetic metal from other parasitic elements. The impedance change clearly depended on the applied pressure. It was also shown that the impedance change could be explained by a change in relative permeability, according to the theory of the SI effect. The radial stress in the diaphragm and the relative permeability exhibited a linear relationship. At a measurement frequency of 200 MHz, the largest sensor response, with a gauge factor of 385.7, was found. It was in the same order as the conventional sensors. As the proposed device is very simple, it has the potential for application as a cheap pressure sensor.

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49

Yahia, Mohammed Ben, Kamel Boughrara, Frédéric Dubas, Lazhar Roubache, and Rachid Ibtiouen. "Two-Dimensional Exact Subdomain Technique of Switched Reluctance Machines with Sinusoidal Current Excitation." Mathematical and Computational Applications 23, no. 4 (October 11, 2018): 59. http://dx.doi.org/10.3390/mca23040059.

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This paper presents a two-dimensional (2D) exact subdomain technique in polar coordinates considering the iron relative permeability in 6/4 switched reluctance machines (SRM) supplied by sinusoidal waveform of current (aka, variable flux reluctance machines). In non-periodic regions (e.g., rotor and/or stator slots/teeth), magnetostatic Maxwell’s equations are solved considering non-homogeneous Neumann boundary conditions (BCs). The general solutions of magnetic vector potential in all subdomains are obtained by applying the interface conditions (ICs) in both directions (i.e., r- and θ-edges ICs). The global saturation effect is taken into account, with a constant magnetic permeability corresponding to the linear zone of the nonlinear B(H) curve. In this investigation, the magnetic flux density distribution inside the electrical machine, the static/dynamic electromagnetic torques, the magnetic flux linkage, the self-/mutual inductances, the magnetic pressures, and the unbalanced magnetic forces (UMFs) have been calculated for 6/4 SRM with two various non-overlapping (or concentrated) windings. One of the case studies is a M1 with a non-overlapping all teeth wound winding (double-layer winding with left and right layer) and the other is a M2 with a non-overlapping alternate teeth wound winding (single-layer winding). It is important to note that the developed semi-analytical model based on the 2D exact subdomain technique is also valid for any number of slot/pole combinations and for non-overlapping teeth wound windings with a single/double layer. Finally, the semi-analytical results have been performed for different values of iron core relative permeability (viz., 100 and 800), and compared with those obtained by the 2D finite-element method (FEM). The comparisons with FEM show good results for the proposed approach.

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50

Si, Wen-Rong, Chen-Zhao Fu, Xu-Tao Wu, Xiu Zhou, Xiu-Guang Li, Yi-Ting Yu, Xiao-Yu Jia, Jian Yang, and Hervé Laurent. "Numerical Study of Electromagnetic Loss and Heat Transfer in an Oil-Immersed Transformer." Mathematical Problems in Engineering 2020 (September 28, 2020): 1–13. http://dx.doi.org/10.1155/2020/6514650.

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Transformer is one of the most important pieces of equipment in power system. The insulation aging and lifespan of transformer are significantly affected by hot spot distributions of internal components inside. In the present paper, the electromagnetic losses of different components and heat transfer process in a three-phase forced oil circulation transformer (400 kVA-15 kV/400 V) are numerically studied with finite element method. The leakage magnetic flux and eddy current loss density for metal components and oil tank are carefully analyzed, and the effect of metal components’ electromagnetic loss on hot spot temperature of different components and oil flow in transformer is also studied. It is found that the surface current of metal components is generated by leakage magnetic flux, and surface current density is large when leakage magnetic flux concentrates. The effect caused by relative magnetic permeability of metal components is remarkable on electromagnetic loss of metal components and oil tank, while the effect caused by relative magnetic permeability of transformer tank is relatively small. Due to the mixing of metal components on oil flow, the heat transfer of core is enhanced, its hot spot temperature is lowered, and the hot spot locations of coil and core also change. These results are meaningful for further understanding of heat transfer process in transformer and important for the optimal design of transformer.

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