• 자원환경지질
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• 제36권6호
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• pp.537-543
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• 2003

황철석은 흔히 유비철석과 밀접히 공생하여 산출되므로 유비철석을 포함하는 황철석을 약광물로 이용할 때에는 비소의 독성에 대한 세심한 주의가 필요하다. 독성을 감소시키기 위해서는 약재를 가열하여 식초에 담금질하는 전통적 초쉬법을 적용하여 왔다. 초쉬법의 과학적 효과를 검토하기 위해 유비철석을 포함하는 황철석 약재를 45$0^{\circ}C$, $650^{\circ}C$ 그리고 85$0^{\circ}C$ 각각의 온도에서 가열하여 식초에 담금질하는 과정을 5회까지 반복하였다. 약재 내 유비철석은 45$0^{\circ}C$에서 초쉬법을 5회 실시하여도 잔존하나, $650^{\circ}C$에서는 초쉬법을 1회 실시하면 완전히 제거된다 45$0^{\circ}C$에서 수치된 약재에서는 비소가 상당량 함유되어 있으나, $650^{\circ}C$와 85$0^{\circ}C$ 에서 수치된 약재에서는 비소함량이 급격히 감소한다. 약재로부터 수용액으로 용출되는 비소 용출량이 가장 적은 수치조건이 가장 효과적인 수치법일 것임을 전제로 비소 용출실험을 실시하였다. 수용액내 비소의 용출량은 45$0^{\circ}C$에서 가장 높고, $650^{\circ}C$와 85$0^{\circ}C$에서는 급격히 감소한다. 그러나 85$0^{\circ}C$에서 수치된 약재의 비소 용출량도 음용수 수질기준을 초과한다. 수치온도가 높을수록 유비철석의 제거가 증대되고 약재 내 비소함량과 비소 용출량이 감소하나, 수치횟수의 효과는 뚜렷하지 않다. 수치횟수 보다는 수치온도가 상대적으로 비소제거에 중요한 요인이며, 비소제거를 위해서는 $650^{\circ}C$ 이상의 온도에서 황철석을 수치하는 것이 필요하다.

• Journal of Nutrition and Health
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• 제36권2호
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• pp.154-166
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• 2003

To investigate the effects of isoflavone supplementation on both bone mineral density and hormone variation in premenopausal women who had decreased bone mass, the 24 subjects were divided into two groups: one was the underweight group, consisting of 13 subjects, and the other was the normal weight group consisting of 11 subjects. For each group, we investigated the effects of isoflavone supplementation of 90 mg/day on both bone mineral density and hormone variation during 3 menstrual cycles. Anthropometric measurements, dietary recall, and analyses of blood and urine were assessed from baseline to post-treatment. The results were as follows: The average age of the underweight group was 21.8 years old and that of the normal weight group was 23.2 years old. The comparative results for the two groups at baseline were as follows: Onset of menarche, menstrual cycle, and menstrual length were not significantly different between the groups. Serum protein, total, HDL-, LDL-cholesterol, triglyceride, Ca, P, Mg, Cu, and Zn level were not significantly different between the groups. Serum estradiol, SHBG, LH, and FSH level were also not significantly different between the groups. Lumbar spine BMD by T scores of the underweight group was significantly lower than that of the normal weight group. Serum osteocalcin, urinary DPD, and urinary pH were not significantly different between the groups. The comparative results for the two groups at post-treatment were as follows: From baseline to post-treatment, the intake of energy, nutrients and isoflavone in food did not significantly change in either group. Serum protein, total cholesterol, HDL-, LDL-cholesterol, and triglyceride levels did not significantly change in either group. Serum Ca, Cu, and Zn levels were significantly lower in both groups and serum Mg level significantly decreased only in the underweight group. Serum estradiol levels were significantly lower in both groups, but serum SHBG, LH, and FSH levels did not significantly change in either group. Lumbar spine BMD by T score of the underweight group significantly increased to 15%, but that of the normal weight group did not significantly change. Serum osteocalcin of the underweight group significantly increased to 28%, while that of the normal weight group significantly increased to 40%. Urinary DPD of the normal weight group significantly increased to 12%. The results show that the BMD of the underweight group was lower than that of the normal weight group. Therefore, the underweight group had a disadvantage in obtaining maximum bone mineral density. The results also show that isoflavone supplementation during 3 menstrual cycles was effective in increasing the bone mineral density of the lumbar spine and affected bone metabolism markers in premenopausal underweight women. Therefore, it can be concluded that sufficient intake of isoflavone could be helpful in preventing decreases in bone mass among premenopausal women, especially underweight women.

• 한국버섯학회지
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• 제18권3호
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• pp.234-243
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• 2020

액체종균으로 생육된 표고의 이화학적 특성 및 항산화 활성을 수확 주기에 따라 비교하였다. 수확 주기가 경과 됨에 따라 수분 함량은 유의차가 없었으나, 조지방 및 조단백질 함량은 감소되는 경향이었다. β-Glucan 함량은 1주기 버섯에서 가장 많았으며, 2 및 3주기 버섯은 1주기 버섯의 68.5% 및 62.3% 수준이었다. 무기물은 버섯의 갓과 대에서 비슷한 함량이었으며, 2주기 버섯의 갓에서 무기물 함량은 가장 많았다. 구성 및 유리아미노산은 수확 주기가 경과됨에 따라 감소되는 경향이었으며, 필수아미노산 함량은 1주기 버섯에서 가장 많았다. 총 페놀 함량은 1주기 버섯의 갓에서 31.96 mg/100 g, 대에서 21.10 mg/100 g으로 가장 높았으며, 수확 주기가 경과됨에 따라 감소되는 경향이었다. 플라보노이드 함량은 1주기 버섯의 갓에서 11.13 mg/100 g이었으며 수확 주기가 경과됨에 따라 유의적으로 감소되었다. 또한 항산화 활성도 1주기 버섯에서 가장 높았으며, 수확 주기가 경과됨에 따라 유의적으로 감소되는 경향이었다. 따라서 액체종균으로 생육된 표고의 3주기 버섯은 품질특성면에서 1주기 버섯에 비해 시장성에 손색이 없을 것으로 생각된다.

• 아시안잔디학회지
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• 제9권4호
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• pp.275-284
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• 1995

In this investigation, the accumulation mineralization and annual cycle of organic P has been studied in grassland ecosysterns of a Z japonica grassland and a M sinensis grassland on Mt. Kwanak. The basic models of the accumulation and mineralization for ash components of a grass-litter have been presented as the equations (1), (2), and (3). The equations (7)~(10) for organic P are derived from these basic concepts. There was a highty significant relationship between organic matter and organic P. The estimates between organic matter and organic P correlated very high significance. The parameter factors k or k' of mineralization of organic P for the Z. japonica and M sinensis asslands were k=0.412 or k'=0.292 and k=0.224 or k'=0.183, respectively. The time required for a cycle to be completed from organic P to inorganic P of 50, 95 and 99 % are 3.9, 16.7 and 27.8 years in the Z. japonica grassland and 4.1, 17.7 and 29.4 years in the M sinensis grassland. The annual P cycle formulae for mineralization were based on the equations (5), (11) and (12). Annual yields of mineralization for organic P in the steady state grasslands of Z. japonica and M sinensis were 0.407 and 0.504g /$m^2$, respectively.

• The Korean Journal of Ecology
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• 제10권4호
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• pp.183-193
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• 1987

An investigation was performed to draw the decy map of litters on the floors of pine and oak forests in Korea and to reveal the turnover cycles of N, P, K, Ca and Mg in litters. Isodecay constant lines of litter organic matter, which are depended upon the altitude, latitude and orientation, were drawn on the Korean map. The decay constants of organic matter of litters were higher in the broadleaf tree forests than in the needleleaf tree forests, and in the grasslands than in the forests. The amount of mineral nutrients such as N, P, K, Ca and Mg returned annually to soils is higher in the broadleaf tree forests than in the needle leaf tree forests, and highest in the Quercus mongolica forest of the forests.

• 아시안잔디학회지
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• 제11권4호
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• pp.295-301
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• 1997

The cycle of heavy metal, copper, was investigated in dynamic grassland ecosystems at a steady state in a Zoysia japonica and a Miscanthus sinensis ecosystem in Mt Kwanak, Korea. Total average storage amounts in Z. japonica and M sinensis grasslands were copper 23.92mg /$m^2$ and 51.82mg /$m^2$ respectively. Estimates of decay constants for based on experimental and mathematical model, were 0.18 in Z. japonica grassland, and 0.30 in M sinensis grassland. Decay half time of copper were 3.85 years in Z. japonica grassland and 2.31 years in A'. sinensis grassland. 95% decay times of initial copper amounts in Z. japonica and A'. sinensis were 16.68 and 9.99 years. Needed times to decay almost all of elements in Z. japonica and M sinensis grassland were 27.80 years and 16.65 years respectively. The copper was losed more rapidly in M. sinensis than in Z. japonica grassland.

• Ocean and Polar Research
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• 제36권4호
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• pp.319-326
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• 2014

Mineral dust in the polar snow plays an important role both in the climate system of the Earth and in global biogeochemical cycles. Analysis of the concentration and the particle size distribution of mineral dust has been carried out in the snow from the Antarctic surface snow and the Greenland snowpit. Among the various particle size determination techniques, a Multisizer 3 Coulter Counter in a class 100 clean bench counted all particles between 1.1 and $30.0{\mu}m$ with a $50{\mu}m$ aperture tube. The aperture tube size, the concentration of electrolytes and the accuracy of the particle size distribution were determined in this study. The number concentrations from the Antarctic surface snow were 81,843 particles $mL^{-1}$, but those from the Greenland snowpit were 10,666 particles $mL^{-1}$. In the volume distribution, the distributions of mineral dust in both the Antarctic surface snow and the Greenland snowpit showed lognormal distribution in the size interval 1.1 to $6.0{\mu}m$ with the mode, 3.562 and $3.836{\mu}m$, respectively. The analysis technique using a coulter counter for mineral dust could be used for reconstructing paleoclimates from polar ice cores.

• Tribology and Lubricants
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• 제21권6호
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• pp.263-267
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• 2005

The tribological performance of multi-walled carbon nanotubes (MWNT) in mineral oils is investigated at ambient temperature. The frictional forces, wear amounts and cycles to scuffing of the oils with nanotubes and without those were measured using the ball-on-disk tester. It was found that there were little differences in the frictional forces and wear amounts of two oils. However, the scuffing times of oils with nanotubes were much longer than those of oils without nanotubes in sliding tests. The nanotubes were very effective on maintaining the oil gap and protecting the surfaces in boundary lubricated sliding.

• 아시안잔디학회지
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• 제9권2호
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• pp.109-117
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• 1995

An investigation was performed to reveal the relation of the production and decomposition of the Zoysia japoni ica and Miscanthus sinensis litters on Mt.Kwanak. The decay constant k of litters was as follows; k of Zoysia japonica, k=0.44, k of Miscanthus sicensis, k=0.33 The time required for the decomposition of half of the accumulated organic matter of Zoysia japonice and Miscanthus sinensis was 1.6 and 2.1 years, respectively. The amount of mineral nutrients returned annually to soil is faster in the ZQvsia japonica grassland than in the Miscanthus sinensis grassland on Mt. Kwanak. Key words: Organic rnatter synthesis, Decomposition balance.

• 한국농공학회논문집
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• 제47권6호
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• pp.27-34
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• 2005

The purpose of this study is to improve the durability performance of polymer modified cement composites for repair of concrete under combined aging conditions. The experimental procedure was divided into three parts. First, the replacement level of mineral admixtures in polymer modified cement composites were determined in an experimental study based on a Box Behnken design. Second, the flow value, compressive strength and chloride permeability test of sixteen types of mixtures were conducted. Test results show that the polymer modified cement composites were effected on the improvement of the compressive strength and permeability performance. Third, the effects on the replacement level of silica fume mixture was evaluated by the compressive strength, chloride permeability, chemical resistance and repeated freezing and thawing cycles test. They demonstrated that the polymer modified cement composites using mixture of silica fume, fly ash, and blast furnace slag improved the durability performance.