• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.748-754
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• 2012

In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT was performed through discretization of equations of motion and boundary condition. Model of laminated composite shells subjected to a combination of magnetic and thermal fields is developed. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Dynamic characteristic of composite shells for change of magnetic fields is investigated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.653-660
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• 2012

In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT with two different boundary conditions(C-C, S-S) was performed through discretization of equations of motion and boundary condition. Model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence for each boundary conditions are investigated and pertinent conclusions are derived.

• Advances in nano research
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• 제7권5호
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• pp.337-349
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• 2019

The size-dependent vibration analysis of a cross-/angle-ply laminated composite plate when embedded on the Pasternak elastic foundation and exposed to an in-plane magnetic field are investigated by adopting an analytical eigenvalue approach. The formulation, which is based on refined-hyperbolic-shear-deformation-plate theory in conjunction with the Eringen Nonlocal Differential Model (ENDM), is tested against considering problems for which numerical/analytical solutions available in the literature. The findings of this study demonstrated the role of magnetic field, size effect, elastic foundation coefficients, geometry, moduli ratio, lay-up numbers and fiber orientations on the nonlocal frequency of cross-/angle-ply laminated composite plates.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2011년도 임시총회 및 하계학술연구발표회
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• pp.93-95
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• 2011

In this study we tried to measure the effect of magnetic field on the dielectric properties of $BaTiO_3-MgFe_2O_4$ soft magnetic composite. Composites with different weight percents of ferroelectric and ferromagnetic phases were subjected to magnetic field in the order of 0 to 450 Oe and the variation of the dielectric properties was observed. The Variation of dielectric polarization was discussed in terms of Maxwell-Wagner type polarization in particulate composites.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1288-1289
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• 2006

Innovative SMC with low iron loss was made from iron powders with evaporated MgO insulation coating. The coating had greater heat-resistance than conventional phosphatic insulation coating, which enabled stress relieving annealing at higher temperature. Magnetic properties of toroidal samples (OD35mm,ID25mm, t5) were examined. The iron loss at 50Hz for Bm = 1.5T was lower 50% of conventional SMC and was almost the same with silicon iron laminations(t0.35). It became clear that MgO insulation coating has enough heat resistance and adhesiveness to powdersurface to obtain innovative SMC with low iron loss.

• 동굴
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• 제78호
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• pp.9-15
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• 2007

The materials showing high structure dispersion with functional properties were developed on the quartz base and those were obtained by mechano-chemical reaction technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, containing a dielectric material as a carrying nucleus, particularly the quartz on that surface one or more layers of different compounds were synthesized having thickness up to 1050nm showing magnetic, electrical properties and others. The similarity of the structure of surface layers of quartz particles subjected to mechano-chemical processing and nano-structure cluspol (clusters in a polymer matrics) material was alsoconfirmed by the fact that the characteristics of ferromagnetic quartz of insulating nano-composite powder were changed with time, after its preparing process was completed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.264-267
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• 2005

Soft magnetic iron powders have been coated with polyester or phenol resin. And the coated powder (soft magnetic composite) have been pressed into ring type core over the pressure of 870 MPa. Green density, magnetic flux density, permeability, core loss of the samples were measured to look at the effect of the coating materials and the amount of them. Green density is increased with the amount of coating materials and shows the maximum value, 6.5 $g/cm^3$ at 5 w/o, but decreased over it. And lowest value of the core loss is showed for the 5 w/o coated samples.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 추계학술대회 논문집
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• pp.217-218
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• 2015

Two axial flux permanent magnet (AFPM) machines using soft magnetic composite (SMC) and lamination steel are studied. Generally stator cores of AFPM machines are manufactured using SMC because AFPM machines need 3 dimensional core structures. However, SMC cores have very disadvantages in magnetic properties. Especially permeability value is much lower than that of lamination steel, so magnetic field density is also lower. In terms of core losses, SMC cores have much larger loss values than lamination steel cores because SMC core can't be laminated. In this study, AFPM machine was designed using laminated steel, and iron losses in two machines using SMC and laminated steel were studied. Simulations were carried out by a commercial 3-D FEM tool.

• 공업화학
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• 제17권3호
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• pp.267-273
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• 2006

Melt-blown 방사법으로 Ba-ferrite 포함하는 PP 복합수지를 방사하여 부직포 섬유를 제조하는 공정에서 방사공정인자와 부직포 특성과의 상관관계를 조사하였다. PP 수지와 Ba-ferrite 분말을 혼합한 후 단축 압출 성형기를 이용하여 펠렛 형태로 제조하고 Melt-blown 섬유 방사기를 이용하여 screw turning force (rpm)와 DCD (die-to-collector distance)를 변화시켜 Ba-ferrite 분말이 부직포 섬유의 기계적, 열적, 결정학적 및 자성 특성에 미치는 영향을 조사하였다. SEM 관찰을 통하여 방사 거리가 증가할수록 혹은 screw turning force가 감소할수록 부직포 섬유의 연신율이 증가하고, 섬유의 직경 및 인장강도가 감소하는 것을 알 수 있었고, XRD 측정 결과로부터 방사거리의 증가는 섬유의 결정성을 높이는 것으로 관찰되었다. 복합 부직포에서는 입자가 고분자와 분리되어 고분자와 입자간의 결합력이 떨어져 순수한 PP대비 인장강도가 감소하였다. Ba-ferrite 분말에 의한 부직포의 자성적 성질을 보면 방사거리에 따라 보자력, 최대 자화, 잔류 자화 값은 감소하였다. TGA 측정을 통한 부직포 섬유의 내열성 시험 결과는 방사거리의 감소에 따라 내열성이 증가하였으며 난연성은 Ba-ferrite 분말의 함량 증가에 따라 증가하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.113-116
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• 2004

The materials showing high structure dispersion with functional properties were developed on the quartz base and those were obtained by mechano-chemical reaction technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, containing a dielectric material as a carrying nucleus, particularly the quartz on that surface one or more layers of different compounds were synthesized having thickness up to 10~50 nm showing magnetic, electrical properties and others. The similarity of the structure of surface layers of quartz particles subjected to mechano-chemical processing and nano-structure cluspol (clusters in a polymer matrics) material was also confirmed by the fact that the characteristics of ferromagnetic quartz of insulating nano-composite powder were changed with time, after its preparing process was completed. The magnetic permeability of the sample was decreasing within first two months down by 15~20 %. Then, the magnetic characteristics were almost stabilized steadily and continuously. The observed changes were related with defective structure of the particles, elastic stress relief, and changes of electron density and magnetic moment in deformation zones. This process of stabilization of the investigated properties could be intensified by the thermal annealing heat treatment in short time period of the nano-composite quartz powders at the temperature ranges of 100~15$0^{\circ}C$.