• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.676-680
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• 2003

Dissolution of magnetite powders by 0.05 M citric acid was investigated at $50^{\circ}C$. All the tests were performed in the pH range between 2.0 to 5.0, which was adjusted using nitric acid or sodium hydroxide. Concentration of each of the dissociated chemical species of citric acid under various solution pHs was calculated using the ionization constants. Variation of zeta potential of magnetite with pH changes was also investigated. The dissolution reaction was explained by comparing the concentration of the dissociated chemical species of citric acid with the zeta potential. Longer than 3 h of induction time was required to dissolve the magnetite. The dissolution behaviour of magnetite was well described by the equation. The physical meaning of each parameter was explained successfully from the model equation.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.93-102
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• 1998

In order to study on the bleaching efficiency of flex fabrics, ozone which has been produced by an ozone generator, has been contacted with flex fabrics in water at various conditions. The equipments used for the ozone reatment of flex fabrics were the ozone generator and a liquor/ozone contactor. For the study of the bleaching efficiency on flex fabrics, the Hunter's whiteness, tensile strength, microscopic properties of the ozone treated flex fabrics were measured. The concentration of generated ozone was increased, as the voltage increase, flow ratio decrease and oxygen amount increase. The bleaching efficiency of ozone treated fabrics was increased with increasing the net concentration of ozone. The whiteness ozone of treated fabrics was found to be best when treated temperature was $0-15^{\circ}C$ and treated time was 20 min. The tensile strength of treated fabrics decreased as the treating time increased, and as the temperature raised.

• Journal of Practical Agriculture & Fisheries Research
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• v.14 no.1
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• pp.181-193
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• 2012

There is enough precipitation and sunshine in Lae, Papua New Guinea. pH in soil of yam field averaged 6.4, that is suitable for yam growing. However, a great variation in pH was found from 3.7 to 6.4 in different locations around Lae. EC in the soil was 0.18 mS/cm that has shown short of soil nutrition but ORP was 393mV, allowing to be ideal for yam cultivation. Thoughtful management for soil fertility including supply of organic 1matters is needed for the sustainable organic yam production in Lae region, PNG.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.144-150
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• 2014

Yams (Dioscorea spp), which are edible or medicinal tuber crops, are a important crop in South Korea. Yams require a high level of soil fertility. The various cultural practices such as fertilizing and plowing were tested for marketable tuber production in Chinese yam (Dioscorea opposita). Tuber yield was also affected by organic matters in soil. Application higher level of organic matters result in increased each tuber weight and tuber yield per unit area. The nutrient absorption quantity of the plant such as nitrogen, phosphoric acid, calcium and potassium was increased from 100~120 days after planting, which time to begin tuber enlargement. The tuber yield was increased when the fertilization increased in quantity. Total yield and marketable ratio were the highest in 31~32 kg/10a of nitrogen fertilizer. From above result, income become larger with increase of marketable yield and quality improvement at 63% (27 kg/10a) level of conventional N fertilization (43 kg/10a). The tuber yield was not significantly different between with in various application level of potash fertilizer. Tuber size and weight decreased accordingly to decreased fertilizing level, so the rates of small tubers increased greatly at cultivation without chemical fertilizer. In considering the accumulation rates of allantoin in Chinese yam tubers, the apt harvest season was after October. The allantoin quantity of it was not influenced with nitrogen fertilizing. Moreover it was advantageous with decrease of chemical fertilizer and appropriate fertilizing in soil environment protection. Commercial tuber's number and yield were increased in trenching before planting with trencher compared with rotavating with tractor.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.15-26
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• 2023

Methane production by anaerobic digestion occurs through interspecies electron transfer (DIET), a synthetic metabolism between acetic and methanate bacteria through hydrolysis and acid production steps. In this study, to improve methane yield, the effect of addition of magnetite (Fe₃O₄), a conductor promoting DIET on methane production in food wastewater was investigated, and the effect on methane yield was assessed by methane potential (B_u) and maximum methane production rate [R_m(t₀)] by the operation of batch type anaerobic reactor adding Fe₃O₄. The B_u and R_m(t₀) of food wastewater without Fe₃O₄ were 0.496 Nm³/kg-VSadded and 38.24 mL/day, respectively. The t0 which reached to R_m appeared at 21.06 days during the operation of the anaerobic reactor. The B_u of food wastewater with Fe₃O₄ was 0.502, 0.498, 0.512, 0.510, 0.518, 0.523, 0.524, 0.540, and 0.549 Nm³/kg-VSadded in the treatment of 5, 10, 15, 20, 25, 30, 40, 70, and 100mM-Fe₃O₄, respectively, and the B_u significantly increased to 36.95% with the addition of magnetite in the addition of 15mM-Fe₃O₄. And, the addition of Fe₃O₄ shortened the duration to reach R_m from 21.06 days to the maximum of 14.67 days by the addition of Fe₃O₄. Therefore, the methane yield and production rate of food wastewater significantly improved with the addition of Fe₃O₄.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.3
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• pp.31-39
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• 1968

In this paper microwave power propagated through the cold plasma was analyzed and measured with respect to the external magenetic flux density. The d. c discharge plasma was in the rectangular waveguide in which two electrode was inserted, and also the glass diseharge tube inserted in the ractangular wavegside. The direction of microwave pro-pagation, the axis of the discharge tube and external magnetic flux were perpendicular to each other. It showed that the attenuation and absorption of micro wave power propagated in the plasma was increased as the magnetic flux density, the discharge current and the pressure of the gas were increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1107-1111
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• 2000

마두령 추출물로부터 항균활성물질을 분리하여 천연항균제로서 이용하고자 식품의 부패 및 식중독과 관계는 미생물에 대한 항균력을 측정한 결과, Gram(+), Gram(-) bacteria, yeast, mold 등 다양한 균주에 대하여 우수한 항균력을 보이며 농도에 비례하여 항균력이 증가하였고, 최소 농도 100ppm에서 미생물 생육저해효과를 보였고, 500ppm의 농도에서 새육이 완전히 억제 되는 것을 볼 수 있었다. 마두령 추출물의 열 및 pH 안정성 실험결과, 다양한 범위의 온도(4$0^{\circ}C$~15$0^{\circ}C$) 및 pH(4~10) 범위에 관계없이 동일한 항균력을 보여 열과 pH에서도 안정함을 알 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06b
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• pp.176-180
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• 2008

본 논문은 마야(Maya) 3D 콘텐츠를 제작하는데 있어서 물, 불, 안개, 폭파 장면과 같은 특수한 효과를 표현하는 방법에 대하여 연구하였다. 마야를 이용하여 3D 콘텐츠를 제작시 특수 효과는 주로 마야의 다이나믹스를 활용한다. 본 연구에서는 마야로 구현된 객체에 에프터이펙트를 사용하여 특수효과를 표현 방법을 연구하였다. 마야 다이나믹스에 비해 에프터 이펙트는 실시간 렌더링이 가능하고, 텍스쳐 에니메이션이 마야의 다이나믹스 보다 사용하기 편리하며, 다양한 표현이 가능하다. 본 논문에서는 마야 다이나 믹스의 장단점과 에프터 이펙트의 장단점을 설명하고 각각의 효과를 적용한 결과를 제시한다.

• 월간 기계설비
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• s.295
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• pp.57-68
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• 2015

내전 후 전쟁 상처를 복구 중에 있는 이라크는 주택, 인프라, 사회 서비스망 구축의 필요에 따라 지난 2010년 이라크 기획청(Ministry of Planning, MOP)이 이라크의 삶의 질 개선을 위한 국가개발계획(Iraq National Development Plan, 2010 ~ 2014)을 수립하고 15개 주정부와 쿠르드 자치정부 지역에 100만호 주거 시설 제공을 위한 국가 주택 프로그램을 발표했다. 이에 따라 2017년까지 주택과 교통인프라, 에너지, IT, 의료, 보안 등에 걸쳐 총 2,750억불(약 300조원)을 이라크 재건사업에 투자할 계획이다. 또 2030년까지는 에너지 분야에 5,000억불 투자 등 정유공장, 발전소, 도로, 인프라, 공공시설 및 군시설 등 다양한 분야에 최소 7,000억불에 달하는 예산을 투입할 예정이다. 한화건설은 지난 2012년 80억 달러 규모의 이라크 비스마야 신도시 건설공사를 수주해 우리나라 해외건설 역사상 최대 규모의 프로젝트 기록을 세웠다. 또한 이 계약으로 우리나라 해외건설 누적 수주액 5,000억 달러 돌파에 크게 기여했다. 윤창기공(주)(대표 백종윤)는 비스마야 현장에서 PC 플랜트 현장의 기계설치공사와 하우징 현장의 기계설비 및 소방공사를 담당하고 있다. 본지는 이라크 현장에 있는 윤창기공(주) 정몽준 소장과 김용우 소장을 이메일로 만나 보았다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.1
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• pp.64-72
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• 1993

We propose "algorithm MA" which can detect PSF that is the functional fault in RAM. This algorithm based on the restricted PSF(or neighborhood PSF) and can detect not only conventional stuck-at and transition faults but also SNPSF, PNPSF and partially ANPSF. The time complexity of "algorithm MA" has 1536xP(P=no. of partition). We propose total BIST(built-in self test) scheme which implement this algorithm in memory chip.ithm in memory chip.