• Journal of Powder Materials
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• v.15 no.6
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• pp.471-476
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• 2008

Sintered Nd-Fe-B magnets have been widely used due to their excellent magnetic properties, especially for driving motors of hybrid and electric vehicles. The microstructure of Nd-Fe-B magnets strongly affects their magnetic properties, in particular the coercivity. Therefore, a post-sintering process like heat-treatment is required for improving the magnetic properties of Nd-Fe-B sintered magnets. In this study, cyclic heat treatment was performed at temperatures between $350^{\circ}C$ and $450^{\circ}C$ up to 16 cycles in order to control microstructures such as size and shape of the Nd-rich phase without grain growth of the $Nd_{2}Fe_{14}B$ phase. The 2 cycles specimen at this temperature range showed more homogeneous microstructure which leads to higher coercivity of 35 kOe than as-sintered one.

• Journal of Powder Materials
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• v.16 no.4
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• pp.285-290
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• 2009

HDDR treated anisotropic Nd-Fe-B powders have been widely used, due to their excellent magnetic properties, especially for sheet motors and sunroof motors of hybrid and electric vehicles. Final microstructure and coercivity of such Nd-Fe-B powders depend on the state of starting mother alloys, so additional homogenization treatment is required for improving magnetic properties of them. In this study, a homogenization treatment was performed at $900\sim1140^{\circ}C$ in order to control the grain size and Nd-rich phase distribution, and at the same time to improve coercivity of the HDDR treated magnetic powders. FE-SEM was used for observing grain size of the HDDR treated powder and EPMA was employed to observe distribution of Nd-rich phase. Magnetic properties were analyzed with a vibrating sample magnetometer.

• Current Applied Physics
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• v.18 no.11
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• pp.1289-1293
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• 2018

The influence of crystallization treatment on the structure, magnetic properties and magnetocaloric effect of $Gd_{71}Ni_{29}$ melt-spun ribbons has been investigated in detail. Annealing of the melt-spun samples at 610 K for 30 min, a majority phase with a $Fe_3C$-type orthorhombic structure (space group, Pnma) and a minority phase with a CrB-type orthorhombic structure (space group, Cmcm) were obtained in the amorphous matrix. The amorphous melt-spun ribbons undergo a second-order ferromagnetic to paramagnetic phase transition at 122 K. For the annealed samples, two magnetic phase transitions caused by amorphous matrix and $Gd_3Ni$ phases occur at 82 and 100 K, respectively. The maximum magnetic entropy change $(-{\Delta}S_M)^{max}$ is $9.0J/(kg{\cdot}K)$ (5T) at 122 K for the melt-spun ribbons. The values of $(-{\Delta}S_M)^{max}$ in annealed ribbons are 1.0 and $5.7J/(kg{\cdot}K)$, corresponding to the two adjacent magnetic transitions.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.855-856
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• 2006

Magnetic nerve stimulation treatment is much backward real condition than other field. Specially, successful medical treatment introduction of magnetic field (MF) can was refered long ago in Avicenna's work, and is thought as age of medicine magnetology development recently. These development is achieved through biologist and biophysicist and clinician's joint effort, but, new mountings and relationship air tassel are developed steadily. Magnetic nerve stimulation treatment field designs treatment system by each function during long wave high-amplitude (traditional magneto therapy of greatly great that strong that) short time that CMF, VMF, PMF field etc. are representative but are HPMT technology in this research and manufacture and special quality did comparative analysis.

• Progress in Superconductivity
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• v.13 no.3
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• pp.178-183
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• 2012

Two $RuSr_2(EuCe)Cu_2O_z$ samples (as prepared and after $N_2$ treatment) have been investigated by thermogravimetric (TC) analysis, high-resolution x-ray powder diffraction and magnetization measurements. TG measurements which were carried out in $H_2/Ar$ atmosphere showed that the $N_2$ treatment of the as-prepared sample at $650^{\circ}C$ for 2h leads to a decrease in the oxygen content z by about 0.25. This oxygen depletion was accompanied by an increase in the magnetic transition temperature from 54.0 K to 114.9 K. This magnetic behavior is discussed in connection with the results of Rietveld analysis of the x-ray diffraction data which showed that the $N_2$ treatment resulted in both a significant increase in the rotation angle of the $RuO_6$ octahedra and a decrease in c-lattice parameter of the sample.

• The KSFM Journal of Fluid Machinery
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• v.17 no.2
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• pp.35-40
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• 2014

The optimal removal efficiency to develop wastewater treatment system using the magnetic ion exchange resin. The secondary sedimentation effluent of wastewater in W wastewater treatment plant located in Gyeong-gi Province was used as the influent. To compare the sedimentation effluent reacted with the magnetic ion exchange resin to the influent, the concentrations of CODmm, TN, $NO{_3}^-$-N and TP were measured. The flux of the influent and HRT were set to 250 mL/min, 10 min, respectively, and BVTR has adjusted to 200, 150, 100. The removal efficiency of CODmn, TN, $NO{_3}^-$-N and TP in the 200 BVTR from 71%, 40.37%, 46.34%, 42.03%, 150 BVTR from 55.22%, 37.83%, 50.38% 41.6% and 100 BVTR from 74%, 59.15%, 79.94%, 79.16%, respectively. The results on 200 BVTR, 150 BVTR, 100 BVTR tests show that 100 BVTR is the optimal factor capable of the highest rate of rejection of the organic material.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.38-45
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• 1989

The Cu-Fe permanent magnet were prepared in situ process, which has economic and mass productive merits in producing multi filamentary composites. The purpose of this research was to study the effect of reduction ratio and heat treatment on magnetic property. As the reduction ratio of Cu-Fe wire increased, the filament structure became finer and interfilament distances decreased and the morphology of filament cross section became ribbon shape. As Fe content increased significantly. The coercivity and squareness of Cu-55 wt%Fe composite increased as a reduction ratio became higher, whereas they increased to maximum values at 0.09 mm ${\phi}$ for Cu-30 wt%Fe, and 0.066 mm ${\phi}$ for CU-45 wt%Fe respectively, and decreased for further reduction. The magnetic properties of Cu-Fe composites can be more enhanced by intermediate heat treatment. The best magnetic properties were obtained from Cu-55 wt%Fe composite deformed to 0.054 mm ${\phi}$ and annealed.

• Korean Journal of Psychosomatic Medicine
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• v.11 no.1
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• pp.52-59
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• 2003

Objective: The purposes of this study were to investigate anxiety and depression that can mediate stress and elicit a response from the women with urinary incontinence and compare the anxiety and depression level before and after treatment of extracoporeal magnetic innervation. Method: Fifty-five women with urinary incontinence were included from a obstetrics and gynecology cilnic. Beck Anxiety Inventory(BAI), Beck Depression Inventory(BDI), Spielberger State-Trait Anxiety Inventory(STAI) were administered before and after treatment of extracoporeal magnetic innervation. Results: The women with urinary incontinence had higher levels of anxiety and depression. Anxiety and depression were reduced after treatment of extracoporeal magnetic innervation regardless of improvement incontinence. Conclusion: Therapies including extracoporeal magnetic innervation may be intrumental in improving anxiety and depression, If the patient do not show improvements of anxiety and depression after treatment for their urologic disorder or if the therapy is unsuccessful, appropriate referral is indicated.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.252-257
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• 1991

This paper proposed that the eddy-current measurement method can be used a means of in-process measuring the hardening depth in Laser surface treatment process. Also, this paper deal with the numerical analysis of magnetic flux distribution and experimental result of measurement. In Laser heat treatment process of steels, a thin layer of the substrate is rapidly heated to austenitizing temperature and subsequently cooled at a very fast rate due to the self-quenching by heat conduction into the bulk body, to produce a martensite structure which have low magnetic permeability. The eddy-current measurement method depends on the properties of material to be measured such as electric conductivity, magnetic permeability and geometry. In this paper, the hardening depth was measured by detecting relevant magnetic permeability changes caused by heat treatment of steels.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.