• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.263-264
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• 2018

Recently, interest in making nanocomposite materials for construction utilizing the excellent physical properties of nano materials is increasing. In this study, basic properties of mortar were evaluated by the dispersion condition of cellulose nano-crystals (CNCs) extracted from nanocellulose and the feasibility of the study was examined. As a result, it was confirmed that the flexural strength and the compressive strength were increased by increasing the dispersion time of the CNCs and by using the ultrasonic dispersing device and the magnetic stirrer together.

• Journal of the Korean Magnetics Society
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• v.15 no.2
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• pp.76-80
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• 2005

It was evaluated whether magnetic beads able to add the functionality of environment purification can be employed in processing soil pollutants. In this study, the micro scale magnetic beads containing carboxyl groups were mixed with water and the soil $(<0.025{\cal}mm) filtered through a sieve, and then it was agitated before isolating the magnetic substances by the use of outer magnetic force. The factors considered at this step were the ratio of soil to magnetic beads, ratio of soil to water, size of the tube where the reaction occur, and intensity of the magnetic force. From the separation experiment between soil and magnetic beads, it was concluded that the magnetic beads and water quantity have an impact on the degree of separation, yet the size of the tube and magnetic force does not have a considerable effect upon that in this small-scaled experiment. Through this experiment, the reaction conditions were optimized to achieve $90\~100\%$ of separation. Therefore, it was concluded that when the functionalized magnetic beads is introduced to environmental processing, it is able to be adopted to the soil processing as well as the water processing.

• Korean Journal of Materials Research
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• v.3 no.6
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• pp.652-660
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• 1993

It was investigated to obtain the relationship between magnetic properties and conditions of forming $Fe_{3}C$ single phase from acicular goethite by heat treatment under the atmosphere of CO and $N_{2}$ mixed gas. X-ray analyses, TEM and VSM measurements were imployed for the characteristics of the carbide. Acicular goethite was sinthesized under proper process parameters. $Fe_{3}C$ single phase was obtained above $550^{\circ}C$, 60min. and $Fe_{5}C_2$ was formed with $Fe_{3}C$ below that temperature. The soturation magnetization of $Fe_{3}C$ single phase was about 100emu/g regardless of the reaction temperature. The coersive force and the ratio of Mr/Ms decreased respectively from 780 to 400 Oe. and from 0.35 to 0.13 with increasing reaction temperature.

• Resources Recycling
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• v.11 no.4
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• pp.44-50
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• 2002

Characteristics on the sulfuric acid leaching of zinc and manganese from the spent zinc-carbon battery powders obtained by cushing and magnetic separation, were investigated with the variation of sulfuric acid concentration, reaction temperature, stir-ring speed and solid/liquid ratio. The sample powders were composed of Zn metal, ZnO, $MnO_2$ and $Mn_2$$O_3$. and it was found that the selective leaching of zinc was difficult in this system. At the condition of S/L ratio 1:10, IM H$_2$$SO_4$, $60^{\circ}C$ and 200 rpm, leaching rate of Zn and Mn are 92% and 35% respectively. The concentration of Zn and Mn in the leaching solution are 19.5 g/l, 7.8 g/l and pH of that solution is 0.75. It was confirmed at reducing agent should be added to increase e leaching rate of manganese with sulfuric acid.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.21-21
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• 2010

현재 시대에는 자원의 부족으로 인하여 원재료의 낮은 등급을 정제하는 것이 중요하다. 자기분리 기술이 산업 계 원재료들의 정제에 적용되는 것이 기대된다. 예를 들면 고순도의 유리나 절연체를 제작하기 위한 원재료에서 철산화물의 제거는 매우 중요하다. 자기를 띠는 입자들과 자기분리 필터 와이어 사이에 발생하는 끌어당기는 힘은 다른 자기분리와 비교 할 때 초전도 자기분리에서 훨씬 강하다. 초전도 마그네트를 이용하여 높은 자기장을 형성하기 때문에 일반 자기분리의 자성 입자 포획력을 능가한다. 본 연구에서는 습식 조건에서 산업계 원재료로부터 철계 산화물을 제거하기 위해서 초전도 자기문리를 사용하여 실험하였다. 실험에 사용된 시료는 유리원료로 사용되는 2종류로 시료A는 0.1 ~ 0.3 mm의 평균입도를 갖는 모래형상이며 시료B는 평균입도 0.03 ~ 0.1 mm의 고운모래 형태이다. 자기분리를 위해 상온에서 100 mm의 직경을 갖는 600 mm의 높이의 전도냉각형 Nb-Ti 초전도 마그네트를 사용하였으며 시료를 위에서 공급하고 아래로 배출되도록 수직형으로 설치하였다. 시료 500 g과 증류수 2 L를 혼합하여 교반시키고 6 T의 자기장 하에서 실험하였다. 자기분리 필터는 초전도 마그네트에서의 자기장의 분포를 해석하여 디자인하였다. 자기분리 필터의 자기적 특성을 알아보기 위해 진동시료형 자력계를 사용하였다. 산업계 원재료는 X선 형광분석기를 사용하여 성분을 분석하였다. 산업계 원재료를 이용하여 초전도 자기분리를 실시한 결과 철계 산화물은 시료A에서 43.5 %제거되었으며 시료B에서는 77.3%제거되었다.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.106-111
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• 1998

This study has been focused on both estrogenic and proliferating activity of genistein (GEN) and bisphenol A (BPA). GEN and BPA enhance the proliferation of estrogen-dependent MCF-7 human breast cancer cells at concentrations as low as 100 nM of GEN and 8 ng/ml of BP A achieving similar effect to that of estradiol at 1 nM. Expression of the estrogen responsive gene, pS2 was also induced in MCF-7 cells by treatment with genistein at dose as low as 1 nM and BPA at dose as low as 4 ng/ml. Using 21 day-old ovariectomized nude mice, we examined end-bud formation and mammary gland development after treatment with bisphenol A or genistein. Compared with untreated control, mammary gland development and end-bud formation were significantly increased in mice fed genistein or bisphenol A (p<0.05). Taken together, it is concluded that GEN and BP A can act as an estrogen agonist resulting in cell proliferation and induction of the estrogen responsive pS2 gene in MCF-7 cells in vitro and in athymic mice in vivo, respectively. Therefore, it is suggested that GEN and BP A might modulate human endocrine system and these compounds might be considered as a endocrine modulator at the low levels of doses.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.13-17
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• 2005

Potential for measuring mobile cadmium concentration in sandy soil using polymer magnetic beads with carboxyl groups was investigated. Experiments for extracting cadmium were performed with contaminated soils, de-ionized water and magnetic beads. In this neutral experimental condition, reacting cadmium with magnetic beads indicate total amount of cadmium that can be moved in soil. The results showed that the mobile fraction of cadmium in soil could be combined with magnetic beads in short time. After binding between cadmium and magnetic beads, the beads were separated from soil suspension by outer magnetic force. The bound cadmium was dissolved from magnetic beads by acid solutions, which were then analyzed by atomic absorption spectroscopy (AAS). This method can determine mobile heavy metals in sandy soil effectively than existing method which use pollutant chemicals to environments such as EDTA.