• 한국광물학회지
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• 제22권2호
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• pp.115-127
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• 2009

울릉분지 퇴적물의 피스톤 코어 시료에 대하여 X-선 분말 회절분석과 리트벨트 방법의 광물정량 소프트웨어를 이용하여 구성광물을 정량적으로 분석하였다. 퇴적물은 세립질의 석영, 장석, 운모, 비정질 오팔-A, 점토광물, 방해석, 황철석 등으로 구성되어 있다. 이중에서 가장 많은 양으로 나타나는 것은 오팔-A이며, 심도 증가에 따라 함량의 점이적인 증가와 감소를 반복적으로 보여주고 있다. 오팔-A 함량의 심도별 변화와 유기탄소함량의 변화는 유사한 경향을 보여주고 있으며, 오팔-A의 함량이 많은 심도에서 규조각의 화석이 다량 산출되고 있다. 이것은 심해 원양성 환경의 규조각 등으로 구성된 비정질 규산광물이 울릉분지 퇴적물의 주 성분을 이루고 있음을 시사한다. 오팔-A는 코어의 상위구간으로 갈수록 증가되는 경향을 보여주는데, 특히 분지의 가장자리 사면부근에서 채취한 코어에서 상위로 갈수록 증가하는 경향이 뚜렷하게 나타난다. 심도에 따른 탄산염 방해석의 함량은 오팔-A의 함량과는 반비례하는 경향이 나타난다. 이것은 해수면의 상승과 하강에 따라 해수면 상승기에는 오팔-A가 증가하며, 하강기에는 오팔-A가 감소하고 방해석의 양이 증가한 것으로 해석된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.935-938
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• 2001

This paper reports the relation of concrete setting characteristic and lateral pressure in mass concrete wall such as side wall of LNG underground storage tank. In order to estimate the lateral pressure, initial setting time of low heat cement concrete with type of mineral admixture was measured for three concrete mixtures(W/P=41.6%) containing limestone powder, fly ash, and slag powder. As a result, the lateral pressure of the concrete containing limestone powder was the smallest than those of other concretes as well as the initial setting time.

• 한국분말재료학회지
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• 제26권6호
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• pp.493-501
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• 2019

In this work, ultra-fine calcium oxide (CaO) powder derived from eggshells is used as the starting material to synthesize mineral trioxide aggregate (MTA). The prepared CaO powder is confirmed to have an average particle size of 500 nm. MTAs are synthesized with three types of fine CaO-based powders, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A). The synthesis behavior of C3S, C2S and C3A with ultra-fine CaO powder and the effects of C₃A content and curing time on the properties of MTA are investigated. The characteristics of the synthesized MTA powders are examined by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), and a universal testing machine (UTM). The microstructure and compressive strength characteristics of the synthesized MTA powders are strongly dependent on the C3A wt.% and curing time. Furthermore, MTA with 5 wt.% C3A is found to increase the compressive strength and shorten the curing time.

• 한국분말재료학회지
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• 제26권4호
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• pp.282-289
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• 2019

Ti has received considerable attention for aerospace, vehicle, and semiconductor industry applications because of its acid-resistant nature, low density, and high mechanical strength. A common precursor used for preparing Ti materials is $TiCl_4$. To prepare high-purity $TiCl_4$, a process based on the removal of $VOCl_3$ has been widely applied. However, $VOCl_3$ removal by distillation and condensation is difficult because of the similar physical properties of $TiCl_4$ and $VOCl_3$. To circumvent this problem, in this study, we have developed a process for $VOCl_3$ removal using Cu powder and mineral oil as purifying agents. The effects of reaction time and temperature, and ratio of purifying agents on the $VOCl_3$ removal efficiency are investigated by chemical and structural measurements. Clear $TiCl_4$ is obtained after the removal of $VOCl_3$. Notably, complete removal of $VOCl_3$ is achieved with 2.0 wt% of mineral oil. Moreover, the refined $TiCl_4$ is used as a precursor for the synthesis of Ti powder. Ti powder is fabricated by a thermal reduction process at $1,100^{\circ}C$ using an $H_2-Ar$ gas mixture. The average size of the Ti powder particles is in the range of $1-3{\mu}m$.

• 콘크리트학회논문집
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• 제16권3호
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• pp.433-440
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• 2004

In order to improve the performance of concrete, generally, modern cements often incorporate several mineral admixtures. In this study, the experimental included the flow value, air content of mortar containing limestone powder and length change and compressive strength of mortar specimen immersed in sulfate solutions. From the experimental results, the limestone powder cement matrices improved the physical properties and sulfate resistance of cement matrices at $10\%$ replacement ratio of limestone powder. The $30\%$ replacement ratio of limestone powder was significantly deteriorated in sodium sulfate solution. Irrespective of fineness levels of limestone powder, length change and SDF of mortar specimens with only $10\%$ replacement was much superior to the other replacements.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.889-892
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• 2006

In this study, we compared and analysed the early strength properties of mortar according to the kinds and replacement ratio of mineral admixture to select the kinds and replacement ratio of mineral admixture of high early strength concrete. For this purpose, mortar mixtures according to the kinds(FA, MK, ZR, BFS, DM) and replacement ratio(0, 2, 4% by volume of sand) of mineral admixture were selected. From our test data, early-age compressive strength decreased in accordance with the increase of replacement ratio of fly-ash(FA) & blast furnace slag powder(BSF) and, in case of addintion admixture, early-age compressive strength of with containing ZR & BFS appeared higher compared with containing other mineral admixture.

• 한국식품조리과학회지
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• 제27권6호
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• pp.723-733
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• 2011

This study was performed to examine the optimum addition amount of Hizikia fusiformis powder to be used with rice flour in the preparation of Hizikia fusiformis Sulgidduk (traditional rice cake). Hizikia fusiformis powder was added to rice powder at ratios of 5, 10, 15 and 20% (w/w). The moisture content of Sulgidduk was increased with the addition of Hizikia fusiformis powder, whereas the pH content was decreased. The addition also lowered the lightness and yellowness values but increased the greenness value. Mineral contents were increased. Hardness, springiness, and brittleness were decreased, and cohesiveness was increased as the added powder content also increased. In the sensory evaluation of Hizikia fusiformis Sulgidduk, color, flavor, taste, softness, chewiness, moistness, cohesiveness, and overall acceptability characteristics were all highest at the 10% addition level. Thus it can be proposed that this is the ideal level of Hizikia fusiformis addition in terms of the sensory properties of the cooked product.

• 보존과학회지
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• 제32권2호
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• pp.109-121
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• 2016

나전대모칠기는 나전, 대모, 금속선 등을 사용하여 가식한 것으로 금속분을 기물 전체에 뿌려 전체적으로 밝은 색조로 표현한 특징을 가진다. 본 연구는 칠도막 단면을 광학현미경과 SEM-EDS 분석을 통하여 칠도막 단면에 나타나는 재료와 특성을 밝히고자 하였다. 그 결과, 목탄분과 토분을 섞은 바탕칠 위에 진사와 석황이 섞인 칠을 바르고, 그 위에 황동분을 뿌린 것으로 나타났다. 칠층에 섞여 있는 안료의 양은 소량으로 종래의 문양 표현에 쓰인 색칠과는 구별된다. 특히, 나전대모칠기의 칠층에서 진사와 석황의 두 가지 안료를 혼합하여 사용한 예를 확인할 수 있었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제24권2호
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• pp.63-68
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• 2012

Osteoporosis is characterized by the reduced density of mineralized bone matrix. The loss of bone has been attributed to an imbalance between bone formation and bone resorption. The silkmoth is one of the famous traditional tonic medicines. Silkworm pupa was evaluated for its antiosteoporotic activity in an ovariectomized rat model of osteoporosis. The rats were ovariectomized at 6weeks of age and divided into 7 groups. All the groups were fed without calcium diet. The OVX rats were treated with water and silkworm powder for 6 weeks. In OVX rats, the body weight, feeding and water intake quantity did not show a significant change, but the silkworm pupa powder immediately before the eclosion of Yeonrokjam was significantly increased the bone mineral density in the femoral bone. The silkworm pupa powder increased the bone with increasing calcium in serum. These results also showed its protective action through promotion of bone formation. The silkworm pupa powder has a definite antiosteoporotic effect; similar to estrogen, it is especially effective for the prevention of bone fracture induced by estrogen deficiency. The silkworm pupa powder is a promising anti-osteoporotic agent that can prevent bone fractures in osteoporotic patients. The silkworm pupa powder does not show serious side effects because natural herbal medicine origin.

• 동아시아식생활학회지
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• 제16권3호
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• pp.308-314
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• 2006

This study was carried out to investigate the physicochemical quality characteristics of Nouaejelly(jelly using silkworm powder) sericultural products which were manufactured using various levels(0.5, 1, 1.5 and 2%) of silkworm powder. The effects of an additional amount of silkworm powder to Nouaejelly were determined by examining, the physicochemical, sensory, and textural properties. The moisture and crude protein content of the Nouaejelly were higher than that of the control(p<0.05). However, the crude fat content of the Nouaejelly was lower than that of the control(p<0.05). The mineral content increased with increasing addition of silkworm powder. The color of the Nouaejelly became darker with increasing levels of silkworm powder. For the texture measurements, the hardness, gumminess and chewiness of the Nouaejelly decreased with increasing levels of silkworm powder, but those of the jelly were decreased significantly by adding 0.5% silkworm powder(p<0.05). In terms of color, the texture and overall preference of Nouaejelly was highest in the jelly containing 1 % silkworm powder(p<0.05). Overall, the optimal amount of silkworm powder added in the manufacture of Nouaejelly was 1% of the total weight.