• 물과 미래
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• 제27권3호
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• pp.115-121
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• 1994

하구수리계에 있어서 점착성류사의 운동은 응결과 응집(aggregation) 현상에 의해 크게 좌우되며, 이들 현상에 의하여 의결된 입자들의 크기, 모양, 강도는 그 퇴적율과 그리고 부유류사와 오염물질의 변동과정에 영향을 미친다. 본 연구에서는 Brownian 운동에 의해 지배되는 이동성 부유영역과 중력에 의해 지배되는 정체성 부유영역으로 분리하여 점착성입자들의 응집과 응결과정을 모의하였다. 이동성 부유영역에 있어서는 Smoluchowski 모형중 입자들의 무작위 회전을 이용한 최대연쇄 모형으로 응집물질의 사영들을 도출하였으며, 그 회전반경에 의해 사영들의 쪽거리 차원을 구하였다. 저에성 부유영역에서의 응집물질(Brownian 영역을 벗어나 침강하는 응집물질)는 비구형 입자들의 침강으로 간주되어진다. 최종 침강속도 차이로 이들 응집물들은 재차 충돌, 결합하여 보다 큰 응집 입자들을 형성하며, 이들 최종 응집입자들의 사영이 모의되어진다. 최대 Feret's 직경과 Minkowski's sausage logic 개념들을 이용하여 모의되어진 사영들의 둘레 길이에 대하여 쪽거리 차원들을 구하였다.

• Archives of Pharmacal Research
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• 제20권5호
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• pp.480-485
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• 1997

The absorption profile of phenytoin Na emulsion were examined compared to that of phenytoin suspension after oral administration in the rat. The corn oil-in-water emulsion, particle size of $184{\pm}$57.8 nm, was prepared using a microfludizer, and phenytoin Na added by shaft homogenizer. The phenytoin emulsion or suspension, 100 mg/kg, were intubated intragastrically using oral dosing needle and blood samples were withdrawn via an indwelling cannula from the conscious rat. Plasma concentrations of phenytoin were measured with HPLC using phenacetin as an internal standard. The plasma concentration versus time data were fitted to a one compartment open model and the pharmacokinetic parameters were calculated using the computer program, Boomer. The phenytoin plasma concentrations from the emulsion at each observed time were about 1.5-2 times higher than those from the suspension, significantly at time of 5, 6 and 7 hr after administration. The absorption $(k_a)$ and elimination rate constant $(k_e)$ were not altered significantly, however the AUC increased from 65.6 to $106.7{\mu}ghr/ml$ after phenytoin suspension or emulsion oral administration, respectively. From an equilibrium dialysis study, the diffusion rate constant $(k_{IE})$ was considerably higher from the phenytoin Na emulsion $(0.0439 hr{-1})$ than phenytoin suspension $(0.0014 hr{-1})$.

• 폴리머
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• 제30권4호
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• pp.286-292
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• 2006

Super water-absorbent resins were prepared by inverse suspension copolymerization of sodium acrylate, acrylamide and 2-hydroxyethyl acrylate using N, N'-methylene-bis-acrylamide as cross-linker. For the suspension copolymerization, monohexadecyl phosphate was employed as the dispersing agent, cyclohexane as the dispersing medium and potassium persulfate as the initiator. The dependence of water-absorption capacity on the amount of crosslinking agent, oil/water ratio, degree of neutralization and the composition of the copolymer were systematically investigated. Furthermore, the swelling kinetics of the super water-absorbent copolymer was carried out. The absorption of the resins is more than 1800 g/g for deionized water and 100 g/g for 0.9% NaCl solution, respectively. The copolymers showed an increased salt resistance and enhanced water retention of soil.

• 한국물환경학회지
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• 제26권2호
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• pp.326-331
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• 2010

Montmorillonite is one of representative inorganic clay particles. As the characteristics of clay particulate matter in aqueous environment determine the efficiencies of wastewater treatment and some industrial operations, it is essential to understand its aquatic behavior in relation with turbidity. The change of electrokinetic potential of montmorillonite suspension shows that it tends to negatively increase as the pH of suspension increases. In addition, it is observed that its potential is around 0mV when the solution pH is ca. 5. The turbidity of suspension is shown to be very low when pH is lower than its isoelectric point. However, the turbidity gradually enhances according to beyond isoelectric point. These results reveal that the correlation between electrokinetic potential and turbidity for clay mineral suspension is peculiar which should be fundamentally considered for systematic treatment of wastewater.

• 한국임상수의학회지
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• 제17권2호
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• pp.411-415
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• 2000

For comparison with conventional barium-gastrointestinal study, modified method using barium and methylcellulose was performed in 16 normal dogs (4-8 kg) divided into two groups. The group 1 received 8ml/kg of 40% w/v barium suspension only, and group 2 had taken 15 ml/kg of 0.6% w/v methylcellulose after administration 4 ml/kg of 40% w/v barium suspension by feeding tube. The barium suspension was prepared mixing full strength-barium suspension with water and methylcellulose solution was produced by blending methylcellulose sterilized water Sequential radiographs, lateral and ventrodorsal projections were obtained at 5 minute, 20 minute,40 minute. 60 minute and every 30 minutes thereafter, until the contrast is seen in the large intestine Inage qual- ity was rated by three veterinary radiologists as " poor" " fair ". "good", or "excellent" We analyzed the relationship between image quality,, transit time. Between two techniques, the modified method with 4ml of 40% w/v barium suspension and 15 ml of 0.6% w/v methylcellulose showed much better image quality ["excellent" result in 7 of the 8 subjects (88%)] and shorter transit time (107 minutes) toe the cecum. In addition, the best image quality was obtained at 20 and 40 minutes after admin-istration of contrast agent. It call be concluded the modified gastrointestinal study using methylcel-lulose after administration of barium suspension was a simple technique and easily improved the image quality and diagnostic accuracy of gstrointestinal disorders in small animal.racy of gstrointestinal disorders in small animal.

• Applied Biological Chemistry
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• 제43권4호
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• pp.266-270
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• 2000

황토 지장수로 콩나물을 재배하여 콩나물의 생장과 품질에 미치는 효과를 조사하였다. 황토 지장수와 대조구인 수돗물로 콩나물을 재배하여 생육을 비교한 결과, 황토 지장수로 재배한 콩나물이 수돗물로 재배한 콩나물보다 생장이 빨랐는데, $20^{\circ}C$에서 5일간 재배 시 무게와 길이에서 각각 11.4%, 14.9%의 증가를 나타내었으며, $25^{\circ}C$에서 5일간 재배 시는 무게와 길이에서 각각 9.9%, 11.0%의 증가를 나타내었다. 이에 대한 원인을 조사하기 위해 황토 지장수와 수돗물의 무기이온 함량과 pH를 비교하였는데, Ca, Mg, K, Na, Zn, Mn, Cu 등에서 차이가 없었으며 다만 P는 수돗물에서 높게 검출되었다. pH도 거의 차이가 없게 나타나, 무기이온 함량과 지장수의 pH가 콩나물의 생장에 영향을 미쳤다고 할 수 없었다. 한편 황토 지장수로 재배한 콩나물의 무기이온 함량과 아미노산 함량을 조사한 결과 수돗물로 재배한 콩나물과 차이가 없었으며, 황토 지장수와 수돗물로 재배한 콩나물의 색깔과 맛, 향, 전체적인 기호도를 관능검사로 비교한 결과, 색깔과 전체적인 기호도면에서 황토 지장수로 재배한 콩나물이 수돗물로 재배한 콩나물보다 우수했으나, 맛, 향의 경우 유의수준 5%에서 차이가 없었다.

• KSBB Journal
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• 제13권1호
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• pp.26-30
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• 1998

The suspension cultures of Mentha piperita produce menthol which has very low solubility in water due to its hydrophobicity. This can be considered as a factor for its low production in the suspension suspension cultures. Cyclodextrin has the hydrophobic cavity inside the molecule in which menthol can be captured and allow to form a stable complex. The suspension culture of Mentha piperita showed 70% higher production enhancement in the medium containing 1.5%(w/v) $\beta$-cyclodextrin than the control. $\beta$-cyclodextrin had no adverse effect on the cell growth and showed the best result among $\alpha$-, $\beta$- and $\gamma$-cyclodextrins tested in terms of menthol production. We demonstrated that $\beta$-cyclodextrin can be used to enhance the production of menthol in the suspension cultures by capturing hydrophobic menthol into the cavity of cyclodextrin molecules.

• 한국식품과학회지
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• 제21권6호
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• pp.826-831
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• 1989

농후 고추장-물 현탁액의 리올로지 거동을 검토하였다. 리올로지 거동은 Herschel-Bulkley식에 적합하였다. 가수량 12.5-100%의 모든 고추장 현탁액은 전단속도 $0.25-179.20sec^{-1}$에서 항복응력을 갖는 의가소성을 보였으며, 전단속도 $5.16sec^{-1}$ 이상에서는 전단속도가 증가함에 따라 의가소성이 더욱 증가함을 보였다. 또, 이들 의가소성은 가수량의 증가 및 측정온도의 감소로 더욱 약해졌다. 고추장 현탁액의 점조도지수에 대한 온도의존성은 매우 낮았으며 점조도지수 값은 고형분함량의 증가로 낮아졌으나 가열로 증가되었다. 고온에서의 리올로지 거동에 대한 주요인 성분은 발효 중의 미분해 전분 또는 단백질인 것으로 추정되었으며, 식초첨가에 의한 리올로지 거동의 변화는 단지 희석효과에 기인하였다.

• Transactions on Electrical and Electronic Materials
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• 제18권3호
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• pp.151-154
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• 2017

In this article, we investigated the various influencing factors that degraded the lifetime of suspension insulators in 154 kV transmission lines, and showed the possible solutions to avoid such breakdowns. With respect to achieve safety, reliability and aesthetical considerations, the characteristics of transmission and distribution network power cables should be improved. Suspension insulators are particularly important to study, as they have developed to be the main component of transmission lines due to their ability to withstand the electrical conductivity of high-voltage power transmission. Suspension insulators are mostly made from glass, rubber and ceramic material due to their high resistivity. In Korea, porcelain suspension insulators are typically used in the transmission line system, as they are cheaper and more flexible compared to other types of insulators. This is effective from preventing very high and steep lightening impulse voltages from causing the breakdown of suspension insulators used in power lines. Other influential factors affect the lifetime of suspension insulators that we studied include temperature, water moisture, contamination, mechanical vibration and electrical stress.

• 한국세라믹학회지
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• 제21권3호
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• pp.217-220
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• 1984

The leaching of Na-fluor-tetrasilicic mica $NaMg_{2.5}(Si_4O_{10})F_2$ (Na-TSM) in the deionized water was investigated by measuring the pH released Na and Mg contents in the suspension. According to the results it was found that $Na^+$ ions of interlayer in the Na-TSM were easily replaced by $H^+$ ions from the deionized water because $Na^+$ ions of I were repidly diffused to form a large hydrated electric double layer in the suspension.