• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.30-31
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2016.11a
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• pp.85-86
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.295-296
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• 2015

• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.234-240
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• 1993

The water-based magnetic fluids were prepared with the synthesized ultrafine magnetite, dodecanoic acid as surfactant. Characteristics of synthesized ultrafine magnetite were investigated with X-ray Diffraction Pattern, Transmission Electron Microscope, Vibrating Sample Magnetometer and BET analysis. Dispersion characteristics of water-based magnetic fluids were investigated in relation to amounts of surfactant, pH and solid content.

• Journal of the Korean Magnetics Society
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• v.4 no.1
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• pp.1-6
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• 1994

The magnetization dynamics was investigated by solving possible origins of overdamped susceptibility observed in ultra-soft magnetic amorphous thin films. The experimental high frequency spectrum and computational spectrum calculated from Gilbert's equation of motion were compared in order to find proper damping factor $\alpha{\approx}20$ and demagnetizing coefficients $D_{x}{\approx}D_{y}{\approx}D_{z}{\approx}0$ for ultra-soft magnetic films. A magnetization vortex mode was, then, proposed to explain the origin of the reversible susceptibility and other anomalies of the ultra-soft magnetic heterogeneous thin films. In this mode it is suggested that there occur, within the nanoscale structural features of the ultra-soft films, incoherent rotational spin motions that are highly damped by the energy transfer from short wavelength spin wave modes and local defect structure mode interactions.

• Journal of the Korean Society of Visualization
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• v.19 no.1
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• pp.36-42
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• 2021

This study measured the velocity of magnetic particles inside the power generation using external heat sources. Single Plane Illumination Microscopy (SPIM) was used to measure magnetic particles that are simultaneously affected by bubbly flow and magnetic field. It has the advantage of reducing errors due to particle superposition by illuminating the thin light sheet. The hydraulic diameter of the power generation is 3mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 200nm. The excitation and emission wavelengths are 530 and 650nm, respectively. In order to find out the flow characteristics, a total of four velocity fields were calculated in wide and narrow gap air bubbles, between the wall and the air bubble and just below the air bubble. Magnetic particles showed up to 8.59% velocity reduction in the wide gap between air bubbles due to external magnetic field.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.74-80
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• 2004

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, the finishing process of a non-ferromagnetic pipe by a static magnetic field method is introduced and its finishing characteristics is discussed with effective factors by various experiments. From these experimental results, it is found that the magnetic abrasives inserted in the pipe are arranged according to the magnetic force line. Through the experimental, it is possible to estimate the proper supply volume of the abrasive, which in proportional to the diameter of pipe.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.195-204
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• 2012

Biomineralization has been explored for geochemical cycles and microbial tolerance mechanisms to metal toxicity. Here, we are introducing NanoFermentation which enables economic, environmentally friendly, requiring low input energy, and scalable manufacturing of nano-dimensioned magnetite. We are also focusing on controlling factors of crystallite size which can determine superparamagnetism and ferrimagnetism. Controlling factors are such as microbial species, temperature, incubation time, medium composition, substituted elements and their concentration, precursor type, reaction volume, precursor concentration density and their combinations. Crystallite size distribution of biomagnetite depends on the balance between nuclei generation and crystal growth. Biomineralization will elucidate elemental cycles on earth crust and microbial ecology as well as it will be applied to material sciences and devices via massive production of nanomaterials.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.273-275
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• 2007

본 논문은 실리카 코팅 자성 나노입자를 이용한 새로운 DNA의 정제에 관한 것으로 기존의 negative-charged polyanion 형태의 수지 및 실리카 멤브레인 기술을 이용한 제품의 단점인 저속, 고비용의 정제방법을 개선할 수 있는 새로운 정제법을 기술한 것이다.

• Electrical & Electronic Materials
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• v.1 no.3
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• pp.184-196
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• 1988

통칭 particulate media(P.M.)로 일컬어지는 입자형 기록매체는 자성재료가 개개의 particle로 구성되는 자기 기록매체를 말한다. 이 P.M.는 20네기초 정보기록매체로서 steel wire, steel tape이후 등장하여 현재까지 가장 광범위하게 사용되고 있다. P.M.를 포함한 자기 기록매체의 발전사를 요약해 보면 표1과 같다. P.M.중에서도 자기 tape가 차지하는 비중은 절대적이며 특히 viedo tape는 전체 자성체사용량의 약 55%를 점하면서 대량생산에 의한 고품질, 저가격의 장점을 전세계 소비자에게 제공하고 있다. 여기서는 P.M.의 기본물성을 좌우하는 자성체에 대하여 알아보고 P.M.를 품목별로 소개한 다음, P.M.중 가장 많은 생산량을 나타내고 있는 viedo tape의 제조과정을 소개하고자 한다.