• Journal of Pharmaceutical Investigation
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• 제21권3호
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• pp.125-132
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• 1991

Using X-ray crystallography powder diffraction, the quantitative representation method of preferred orientation of particles ill tablets was developed. Selected faces of a tablet. the upper surface and faces cut parallel and normal to the upper surface, were presented to an X-ray beam and X-ray diffraction patterns for these faces were measured. The effects of particle size. tableting pressure, and particle form on the preferred orientation were also investigated. It was also recognized that the degree of anisotropy in terms of capping tendency was influenced by the preferred orientation of particles in tablets.

• Elastomers and Composites
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• 제48권2호
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• pp.167-171
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• 2013

자동차용 선도장 베이스코트 도료에서 사용되는 알루미늄의 입자 크기와 배향에 따른 내후성을 연구하였다. UV를 촉진하여 조사할 수 있는 QUV$^{(R)}$ (Q-LAB) 장비를 이용하여 UV 투과율의 차이에 의한 소재의 손상 정도를 관찰하였다. Conflake 형태의 입자 크기가 서로 다른 3종의 알루미늄 paste를 이용하여 자동차용 선도장 조건으로 베이스코트를 도장하고 투명 클리어를 도장하여 필름과 시편을 제조하였다. 작성된 필름을 UV 투과 장비로 측정한 결과 입자 크기가 작고 수평 배향인 EKART사의 #790을 사용 시 낮은 UV 투과율을 나타내었다. 실제 내후성 시편의 단면 조사에서도 #790, #770, #750 순으로 높은 광택 유지율을 나타내었다.

• 대한기계학회논문집B
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• 제41권7호
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• pp.455-462
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• 2017

외부자기장에 의한 타원형 야누스 자성입자 사이의 자성 상호작용을 직접수치해석을 사용하여 분석하였다. 유한요소법에 기초한 가상영역법을 사용하여 입자계 유동해석을 수행하였고, 자기장 문제에서는 자성 포텐셜에 대한 지배방정식을 입자와 유체를 포함하는 전체영역에 대하여 풀어 자기장을 구하였다. 이 때 구해진 자기장으로부터 구한 맥스웰 응력을 사용하여 개별 입자에 작용하는 자기력이 계산된다. 입자의 운동과 최종적인 조립구조는 입자의 형상비, 개별 입자의 배향, 입자의 초기 분포에 크게 영향을 받는 것이 확인되었다. 또한 입자의 배향은 입자 주위의 유체 유동에도 영향을 주었다. 외부자기장에 의한 타원형 야누스 입자의 최종 조립구조는 앞서 언급한 인자들에 의해서 영향을 받은 것을 수치해석을 통해 확인할 수 있었다.

• 소성∙가공
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• 제15권6호
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• pp.421-427
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• 2006

Drawing process of Al-1%Si bonding wire considering fine Si particle is analyzed in this study using FE-simulation. Al-1%Si boding wire requires electric conductivity because Al-1%Si bonding wire is used for interconnection in semiconductor device. About 1% of Si is added to Al wire for dispersion-strengthening. Distribution and shape of fine Si particle have strongly influence on the wire drawing process. In this study, therefore, the finite-element model based on the observation of wire by continuous casting is used to analyze the effect of various parameters, such as the reduction in area, the semi-die angle, the aspect ratio, the inter-particle spacing and orientation angle of the fine Si particle on wire drawing processes. The effect of each parameter on the wire drawing process is investigated from the aspect of ductility and defects of wire. From the results of the analysis, it is possible to obtain the important basic data which can be guaranteed in the fracture prevention of Al-1 %Si wire.

• 한국자기학회지
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• 제5권5호
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• pp.667-671
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• 1995

The viscometric technique is used to study the effects of microstructure on the viscosity (viscosity vs. concentration or shear rate) of magnetic particle suspensions. In this characterization, measurement of suspension viscosity is used to obtain the dependence of viscous energy dissipation on microstructural state of dispersions. Microstructural shape effects which are related to particle orientation are then indirectly obtained. Empirical formulas from mean field theory and the Mooney equation, which are applicable at high concentration of magnetic particles, are used to relate viscosity to particle concentration. The validity and physical meaning of these equations are discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.111-114
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• 2003

In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternating field vertically to the EPD field has been developed for the first time and applied to the electrophoretic deposition process. The applied alternating electric field caused a force to be exerted on each YBCO particle and resulted in a shaking of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. The usual commercial electrical power was used for the vertically applied alternating voltage and the induced electric field was 25-120 V/cm at 60Hz. The thick film fabricated by the method developed in this paper showed better surface uniformity without crack and porosity and improved film characteristics such as critical temperature ($T_{c,zero}$ : 90 K) and critical current density ($2354\;A/cm^2$). Therefore, it is expected that the shaky-aligned electrophoretic deposition method can be used to fabricate superconductor films through a simpler process and at less expense.

• 한국전기전자재료학회논문지
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• 제16권11호
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• pp.1041-1046
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• 2003

In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternating field vertically to the EPD field has been developed for the first time and applied to the electrophoretic deposition process. The applied alternating electric field, so called Shaky Alternating Assisted Field, caused a force to be exerted on each YBCO particle and resulted in a shaking of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. The usual commercial electrical power was used for the vertically applied alternating voltage and the induced electric field was 25-120 V/cm at 60Hz. The thick film fabricated by the method developed in this paper showed better surface uniformity without crack and porosity and improved film characteristics such as critical temperature (Tc,zero = 90 K) and critical current density (2354 A/$\textrm{cm}^2$), Therefore, it is expected that the shaky-aligned electrophoretic deposition method can be used to fabricate superconductor films through a simpler process and at less expense.

• Bulletin of the Korean Chemical Society
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• 제18권7호
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• pp.767-770
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• 1997

• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.324-331
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• 1995

0.36[wt%l $SiO_{2}$ and 0.1[wt%] $H_{3}$B $O_{3}$ were added to strontium ferrite magnets of the magnetoplumbite phase SrO.5.7F $e_{2}$ $O_{3}$ to hinder grain growth and accelerate sintering, respectively. This experiment was carried out to investigate effect of particle size distribution as a function of milling time(20, 30, 40, 50, 60, 70 hours) on the magnetic properties of SrO.5.7F $e_{2}$ $O_{3}$ ferrite magnet. The B-H curve, density and the degree of orientation were measured. And the microstructure of ferrite magnets was examined with a SEM. The optimal conditions and properties of the typical sample are the following : The milling time was 60 hours. Magnetic and physical properties are $B_{r}$=4, 000[G], $_{b}$ $H_{c}$=3, 330[Oe], (BH)max=3.786[MGOe], $_{I}$ $H_{c}$=3, 525[Oe], density=5.0063[g/c $m^{3}$] and orientation factor f=0.813.0.813.3.3.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1314-1316
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• 1994

$0.36[wtx]Sio_2$ and $0.1[wtx]H_3BO_3$ were added to strontium ferrite magnets of the magnetoplumbite phase SrO $5.7Fe_2O_3$. This experiment was carried out to investigate the effects of particle size distribution as a function of milling time(20,30,40,50,60,70 hours) on the magnetic properties of SrO $5.7Fe_2O_3$ ferrite magnet. The B-H Curve, density and the degree of orientation were measured. The optimal conditions of making magnets and properties of a typical sample are the following : The milling time was 60 hours. Magnetic and physical properties are $B_r$=4000[G], $_BH_c$=3330[Oe], $_IH_c$=3525[Oe], (BH)max=3.786 [MGOe], density= $5.0063g/cm^2$, orientation factor f=0.813.