• 한국세라믹학회지
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• 제44권1호
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• pp.43-51
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• 2007

Fluidity, setting time, hydration heat, bond water ratio, compressive strength, SEM and BET of OPC were measured by adding 1.0 wt% KCl and replacing 20 wt% mineral admixture in order to examine effects of blast furnace slag (BFS), limestone powder (LSP), and fly ash (FA) on fluidity and strength development of the cement contained much chloride. In general, the cement contained much chloride was high in heat of hydration, short in its setting time, low in its fluidity and low in its strength at 28 days due to the rapid hydration in its initial stage. As a result of the experiment, it has been demonstrated that fluidity became improved but the compressive strength at 28 days was decreased as replaced LSP to the cement contained much chloride. the fluidity and compressive strength at 28 days was improved as replaced BFS, the initial compressive strength development was improved due to the activation of initial reaction by KCl. Fluidity, initial compressive strength and late compressive strength at 28 days of cement contained much chloride replaced 5 wt% LSP and 15 wt% BFS concurrently was better than OPC, but the hydration heat was lower.

• 동아시아식생활학회지
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• 제15권3호
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• pp.264-270
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• 2005

This study was performed to evaluate the effect of red-yeast-rice on blood lipids and also to investigated the relation of blood lipids, bone related hormones, and bone mineral density in overiectomized rats. Forty female rats (body weight $210\pm5$g) were divided into two groups. The rats in the first group were ovariectomized which the others received sham operation (SHAM). And then each rat group was further divided into control diet $(casein\;20\%)$ and red-yeast-rice powder supplemented $(0.1\%)$ diet group. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus in spine and femur. Bone formation and bone resorption were measured by serum osteocalcin and urinary deoxypyridinoline (DPD) crosslinks value. Serum growth hormone, IGF-1 and calcitonin were analyzed using radioimmunoassay kits. The red-yeast-rice group had significantly lower the blood triglyceride concentration and had lower the blood total cholesterol concentration than casein group did in ovariectomized rats. And the red-yeast-rice group than casein group in ovariectomized rats. The red-yeast-rice group had significantly lower the atherogenic index than control group within the ovariectomized groups. In the experimental rats, serum total cholesterol concentration was negatively correlated with femur BMC and crosslink value. Crosslink value was negatively correlated with spine BMC and IGF-1. Osteocalcin concentration was negatively correlated with crosslink value. Growth hormone was negatively correlated with crosslink value and positively correlated with spine BMC. The findings of this study suggest that red-yeast-rices are beneficial for blood lipid in ovariectomized rats. And when considering a population-based public health approach to lowering cholesterol and bone loss, and preventing coronary heart disease and osteoporosis, the red-yeast-rice dietary supplement could provide a new approach for the maintenance of healthier cholesterol and bone.

• 암석학회지
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• 제21권4호
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• pp.431-439
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• 2012

원소의 고순도분리는 동위원소계 연구의 기초가 된다. 이 기술보고에서는 Sm-Nd 연대측정법에 중요한 원소군인 Sm과 Nd의 원소분리에 자주 이용되고 있는 HDEHP를 이용한 테플론분말(란탄-레진)법과 Sm-Nd 동위원소계 및 La-Ce 동위원소계의 연구를 위한 원소분리법인 ${\alpha}$-HIBA(${\alpha}$-Hydroxy Isobutyric acid)법의 장단점을 한국지질자원연구원(KIGAM), 기초과학지원연구원(KBSI), 극지연구소(KOPRI) 및 일본 나고야대학과 같은 각 기관별 용리곡선을 통해 비교 소개하였다. 동위원소 지구화학연구를 위한 이 고순도의 원소분리법 비교는 Sm-Nd계 및 La-Ce계 동위원소 지구화학연구자의 실험법 선택에 많은 도움을 줄 것이다.

• 자원리싸이클링
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• 제14권6호
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• pp.37-43
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• 2005

페리튬이온전지로부터 회수된 코발트와 리튬 침출액으로부터 화염분부열분해법에 의하여 $LiCoO_{2}$ 나노분말을 제조하였다. 리튬 및 코발트 성분을 함유하는 전극물질은 열처리 및 기계적 처리에 의해 그 농도를 증가 시켰다. 리튬이온전지 양극물질을 질산으로 용해한 다음 침출액중 Li과 Co의 당량비가 1.0 되도록 $LiNO_{3}$로 조절하여 화염분무열분해용 전구체를 제조하었다. 화염분무열분해법에 의해 제조된 $LiCoO_{2}$ 분말의 평균입자크기는 전구체의 몰 농도가 증가하면서 증가되었으며, 화염온도 역시 입자의 크기를 증가시켰다. 변수실험 결과 $11{\~}35nm$ 크기의 결정형 $LiCoO_{2}$ 나노분말을 제조할 수 있었다 또한 나노 $LiCoO_{2}$의 전극재료로서의 가능성을 확인하기 위하여 충방전 특성 평가와 같은 전기화학적 분석을 수행하였다.

• 한국버섯학회지
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• 제7권3호
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• pp.91-97
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• 2009

느타리버섯의 배지에 철, 고춧가루, 은행잎을 첨가하였을 때 버섯의 생육과 생리활성을 분석한 결과는 다음과 같다. 수량은 춘추 품종에 철 34.9g을 첨가하였을 때 144g으로 가장 높았고, 나머지 품종간에는 차이가 없었으며, 34.9g 및 174.5g 처리시 17.4g 처리에 비해 수량이 높은 경향이었다. 자실체와 배지에 포함된 무기물의 함량은 종류별로 차이가 있었으며, 배지중 철의 함량이 증가하여도 자실체내의 철의 함량은 0.31~0.43mg/kg으로 거의 일정하게 유지되었다. 배지에 포함된 고춧가루의 함량이 많아질수록 자실체에 포함된 캡사이신의 함량도 많아졌으며, 수한품종에서 6mg/100g으로 가장 많이 전이되었다. 철이나 고추를 첨가한 배지에서 재배한 버섯에서 페놀성 화합물의 함량이 높게 나타났으며, 항산화력과 총 페놀성 화합물 함량, 환원력과 총페놀성 화합물 함량, 금속이온 제거능과 페놀성 화합물의 함량 간에는 서로 영향을 미치지 않는 경향이었다. Macrophage 활성화능은 수한 품종이 다른 품종에 비해 높은 경향이었다.

• Restorative Dentistry and Endodontics
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• 제34권4호
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• pp.371-376
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• 2009

이 연구에서는 Mineral Trioxide Aggregate (MTA)와 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) 레진을 혼합하여 치근단 역충전 재료로 사용하였을 때의 미세누출을 MTA, 포틀랜드 시멘트와 비교하였다. 발치된 사람 치아의 근관형성 및 충전 후 치근단 절제와 역충전 와동을 형성하였다. MTA, Portland cement, MTA와 4-META/MMA & TBB레진을 혼합한 각각의 재료로 치근단을 역충전한 후 methylene blue dye에 72시간 동안 침적하여 염료가 침투한 길이를 10배 현미경 하에서 측정하였다. MTA와 4-META/MMA & TBB 레진 혼합 충전 군에서는 포틀랜드 시멘트나 MTA 충전군보다 통계적으로 유의하게 적은 미세 누출을 보였으며, 포틀랜드 시멘트와 MTA 충전군의 미세 누출 정도는 통계적으로 차이가 없었다. 이 실험의 결과로 보아 MTA와 4-META/MMA & TBB레진 혼합 재료는 치근단 역충전시 포틀랜드 시멘트나 MTA에 비해 낮은 초기 미세누출을 보여, 치근단 봉쇄 효과가 우수한 것으로 사료된다.

• 한국재료학회지
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• 제26권6호
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• pp.306-310
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• 2016

To produce 4N grade high-purity silica powder from natural ore, the mineralogical characteristics of natural silica ore were investigated and their effects on the purification process were revealed. The Chinese silica mineral ore used was composed of iron and aluminum as main impurities and calcium, magnesium, potassium, sodium, and titanium as trace impurities; these trace impurities generally exist as either single oxides or complex oxides. It was confirmed that liberation and acidic washing of the impurities were highly dependent on the particle size of the ground silica ore and on its mineralogical characteristics such as the distribution and phases of existing impurities. It is suggested that appropriate size reduction of silica ore should be realized for optimized purification according to the origin of the natural silica ore. A single step purification process, the mechano-chemical washing (MCW) process, was proposed and verified in comparison with the conventional multi step washing process.

• 한국분말재료학회지
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• 제22권1호
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• pp.27-31
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• 2015

Flat panel display devices are mainly used as information display devices in the 21st century. The worldwide waste flat panel displays are expected at 2-3 million units but most of them are land-filled for want of a proper recycling technology More specifically, rare earth metals of La and Eu are used as fluorescent materials of Cold Cathode Flourscent Lamp(CCFL)s in the waste flat panel displays and they are critically vulnerable and irreplaceable strategic mineral resources. At present, most of the waste CCFLs are disposed of by land-filling and incineration and proper recovery of 80-plus tons per annum of the rare earth fluorescent materials will significantly contribute to steady supply of them. A dearth of Korean domestic research results on recovery and recycling of rare earth elements in the CCFLs prompts to initiate this status report on overseas research trends and noteworthy research results in related fields.

• 한국재료학회지
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• 제25권9호
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• pp.492-496
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• 2015

Hydroxyapatite (HA), which is an important calcium phosphate mineral, has been applied in orthopedics, dentistry, and many other fields depending upon its morphology. HA can be synthesized with different morphologies through controlling the synthesis method and several parameters. Here, we synthesize various morphologies of HA using two simple methods: hydrothermal combustion and solution combustion. The phase purity of the synthesized HA is confirmed using X-ray diffractometry. It demonstrates that pure phased hydroxyapatite can be synthesized using both methods. The morphology of the synthesized powder is examined using scanning electron microscopy. The effects of pH and temperature on the final powder are also investigated. At $140^{\circ}C$, using the hydrothermal method, nano-micro HA rods with a hexagonal crystal structure can be synthesized, whereas using solution combustion method at $600^{\circ}C$, a dense cubic morphology can be synthesized, which exhibits monoclinic crystal structures.

• 에너지공학
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• 제26권2호
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• pp.39-49
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• 2017

Coffee is one of the most popular and consumed beverages in the world, which leads to a high contents of solid residue known as spent coffee grounds (SCG). As is known, coffee beans contain several classes of health related chemicals, including phenolic compounds, melanoidins, diterpenes, xanthines and carotenoids. The waste water coming out of coffee industries has high concentration of organic pollutants and is very harmful for surrounding water bodies, human health and aquatic life if discharged directly into the surface waters. Hence it is essential to treat and manage the coffee waste. Oyster shells are a waste product from mariculture that creates a major disposal problem in coastal regions of southeast Korea. In the study, the oyster shell waste was used to treat the coffee waste and its effluents. Oyster shells are calcined at $1000^{\circ}C$ for 2 h, and allowed to test the calcined CaO powder ability to inhibit the growth of bacteria in different aging coffee wastes. Calcined oyster shell powder showed anti-bacterial effect that inhibited cell growth of Escherichia coli and other bacterial forms. The antimicrobial activity of calcium oxide from oyster shell waste for biological treatment and utilization as a fertilizers with economic ecofriendly in nature.