• 한국농공학회논문집
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• 제55권3호
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• pp.75-84
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• 2013

The seepage quantity analysis of reservoir embankment is very important for assessment of embankment safety. However, the conventional analysis does not consider uncertainty of soil properties. Permeability is known that the coefficient of variation is larger than other soil properties and seepage quantity is highly dependent on the permeability of embankment. Therefore, probabilistic analysis should be carried out for seepage analysis. To designers, however, the probabilistic analysis is not an easy task. In this paper, the method that can be performed probabilistic analysis easily and efficiently through the numerical analysis based commercial program is proposed. Stochastic response surface method is used for approximate the limit state function and when estimating the coefficients, the moving least squares method is applied in order to reduce local error. The probabilistic analysis is performed by LHC-MCS through the response surface. This method was applied to two type (homogeneous, core zone) earth dams and permeability of embankment body and core are considered as random variables. As a result, seepage quantity was predicted effectively by response surface and probabilistic analysis could be successfully implemented.

• Korean Membrane Journal
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• 제4권1호
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• pp.36-40
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• 2002

The diffusion coefficients of ions in the reverse transport system using the carrier mediated membrane were estimated from the diffusional membrane permeabilities and the ion activity in membrane system. In the aqueous alkali metal ions-membrane system diffusional flux of alkali metal ions driven by coupled proton was analyzed. The aqueous phase I contained NaOH solution and the aqueous phase II also contained NaCl and HCl mixed solution. The concentration of Na ions of both phases were $10^{0},\;10^{-1},\;10^{-2},\;5{\times}10^{-1}\;and\;5{\times}10^{-2}\;mol{\cdot}dm^{-3}$ and the concentration of HCI in aqueous phase II was always kept at $1{\times}10^{-1}\;mol{\cdot}dm^{-3}$. Moreover, the carrier concentration in liquid membrane was $10^{-2}\;mol{\cdot}dm^{-3}$. The results indicated that the diffusion coefficients depend strongly on the concentration of both phases electrolyte solution equilibriated with the membrane. The points were interpreted in terms of the energy barrier theory. Furthermore, eliminating the potential terms from the membrane equation was derived.

• 한국염색가공학회지
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• 제6권4호
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• pp.72-76
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• 1994

The permselectivity of alkali metal chlorides through silk fibroin membrane was investigated at $25^{\circ}C$: The Permeability coefficients were found to increase in a sequence of LiCl < NaCl < KCl < CsCl. This sequence was explained by considering the partition and the hydrophilic membrane. The dependence of the permeability on the salts concentration was interpreted by means of TMS theory. The ionic mobility ratio of alkali metal chlorides through this membrane decreased with the increase of the Stokes radius. The Effectiveness of the charged density was found to depend on the ionic species. The greater the Stokes radius the larger the effective charge density of membrane.

• 지질공학
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• 제14권4호
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• pp.487-498
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• 2004

대부분이 산악지 형으로 구성된 부산지 역은 도시의 발달로 인해 산지의 개발이 점차 늘어가는 추세에 있으며, 연구지역인 황령산일대도 개발이 많이 진행되고 있는 지역 중의 하나이다. 도시지 역에서 많은 인명과 재산피해를 초래하는 산사태와 절취사면의 붕괴는 암반특성 못지 않게 토질특성에 영향을 많이 받는다. 따라서 이 연구에서는 1999년 대규모 사면붕괴가 발생되었던 부산 황령산지 역을 대상으로 지질에 따른 토질공학적 특성을 분석하였다. 연구지역의 지질은 백악기 퇴적암과 화산암이 분포하고 있다. 사면의 토층은 점토와 실트가 섞인 모래로 분류되며, 점착력과 내부마찰각은 각각 $0.001\~0.066kg/cm^2$ 및 $32-39^{\circ}$의 범위로서 전단강도가 대체로 높은 지반으로 평가되었다. 투수계수는 $2.34\times10^4\~2.58\times10^{-2}cm/sec$로서 보통정도의 투수성을 가지며, 지질별로는 퇴적암지 역의 투수계수가 화산암지역에 비해 전반적으로 큰 것으로 나타났다.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 추계 총회 및 학술발표회
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• pp.13-20
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• 1993

The sorption equilibria and permeation rates for carbon dioxide in such glassy polymer membranes with high glass-transition temperature as polyimide, polyetherimide, polysulfone and polyethersulfone membranes, were measured. The sorption isotherms for these systems can be described well by the dual-mode sorption model, whereas the pressure dependences of the mean permeability coefficients are simulated better by a modified dual-mode mobility model than the conventional dual-mode mobility model in which the Henry's law and Langmuir populations execute four kinds of diffusive movement.

• 한국가스학회지
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• 제5권1호
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• pp.29-36
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• 2001

Poylsulfone의 phenyl 고리에 각각 -Br과 $-Si(CH_{3})_{3}$ 기능기를 치환시킨 BPSf와 TMSPSf을 합성하고, BPSf막, TMSPSf막 그리고 BPSf/TMSPSf 블렌드막에 대한 $O_{2}$와 $N_{2}$의 투과특성을 조사 $\cdot$ 비교하였다. BPSf막은 PSf막에 비해 높은 이상분리인자를 보였는데, 이는 유도 쌍극자에 의한 사슬간의 극성 상호작용 때문에 사슬간의 인력이 증가하고 따라서 사슬간의 거리가 감소하기 때문이라고 설명할 수 있다. 반면 TMSPSf막의 경우 부피가 큰 $-Si(CH_{3})_{3}$ 의 치환으로 인해 자유부피가 커져 PSf 보다 높은 투과도 계수를 나타내었다. 이러한 상반된 경향을 보이는 BPSf와 TMSPSf을 블렌드하여 제조한 BPSf/TMSPSf막의 경우 PSf보다 이상분리인자는 약간 감소한 반면 높은 투과도 계수를 나타내었다. 고분자의 구조와 투과 특성과의 상관관계를 밝히기 위해 고분자의 자유부피와 투과도 계수를 플로트한 결과, 투과도 계수가 자유부피에 잘 연관됨을 알 수 있었으며, 특히 specific free volme(SFV)과의 연관성이 보다 우수함을 알 수 있었다.

• 한국조경학회지
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• 제28권6호
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• pp.77-83
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• 2001

The purpose of this study is to provide the fundamental material and information for the plant maintenance after rooftop planting through physiochemical characteristics. The characteristics of artificial soils after rooftop planting from 1993 to 1999 was investigated. Fourteen investigation areas were selected from 4 cities(2 areas selected by each year). The analysis of the circumstances of the areas, the physical characteristics, and the chemical characteristics of the soil were conducted. The artificial soil pH ranged 5.26∼7.40 showing that after construction the soil pH tended to decrease. The soil bulk density of the site was lowest in 1999, 0.15g/㎤, and used to increase toward 1993. We found the fact that the soil bulk density increased gradually after rooftop application . The coefficients of permeability of the soils range from 0.016 to 0.052 cm/sec, which seemed to be in good permeability level. The artificial soils had relatively high water moisture capacity of 62.69∼71.36%. The soil organic matter content of the artificial soils ranged from 0.43 to 1.34%. The exchangeable caution concentration in the artificial soil ranged, Na, 2.36∼4.71mg·{TEX}$kg^{-1}${/TEX}, Mg 0.88∼2.84mg·{TEX}$kg^{-1}${/TEX},K 2.97∼9.61 mg·{TEX}$kg^{-1}${/TEX}, and Ca 9.39∼28.23 mg·{TEX}$kg^{-1}${/TEX}. The amount of total N ranged from 0.003 to 0.286% in study sites. Soil chemical properties varied year to year and showed little tend. The research results showed that some characteristics of the artificial soil were changed after rooftop planting, i.e., soil pH and soil bulk density. Soil bulk density had a negative relationship with the coefficient of permeability, showing that the drainage condition might be limited after some period. This study suggests that a diversity of the research in the changes of the plant growth basis on the areas after construction.

• 한국지반환경공학회 논문집
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• 제14권7호
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• pp.51-56
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• 2013

최근, 시강우량의 최대치의 기록이 매년 바뀌고 있으며 이로 인해 도로의 침수피해 사례가 증가하고 있다. 이러한 이유로 새로운 배수포장체가 개발되고 있으나 보조기층에 대해서는 별도의 고려가 없다. 본 연구에서는 보조기층의 강도와 투수성을 함께 고려한 적정입도분포 기준을 제안하며, 이때 실내실험을 통해 각각의 강도특성 및 투수성을 비교하고자 한다. 실험에 앞서 국내외 보조기층 기준에 대한 시방기준을 토대로 4가지의 대표적인 입도분포를 산정하고 이를 실험하였다. 실험에 있어서 강도특성은 회복탄성계수 산정을 비교하고, 투수특성은 수직방향의 상향 및 하향 투수계수를 비교하였다. 회복탄성계수 산정은 $M_R$ 시험을 통하였으며, 이때 본 연구에서는 진동삼축시험기기를 보완하여 이를 구현하도록 하였다. 투수시험의 경우에는 2가지 투수시험이 수행되었으며, 하향의 흐름에 대한 투수시험으로는 기존의 변수위 투수시험이 적용되었고, 상향의 경우 직경 150mm의 중형 Rowe Cell 투수시험기를 이용하여 시험을 수행하였다. 연구결과, 회복탄성계수와 투수계수의 결과들을 종합하여 포장체 보조기층의 강도특성과 투수특성을 모두 만족할 수 있는 적정입도분포를 선정하고, 이를 통해 적정입도기준 마련이 가능할 것으로 판단된다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.621-631
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• 2017

In this paper, we study the various impacts of connecting distributed generation (DG) to the distribution network. The comprehensive evaluation index system (CEIS) of four hierarchies is established, considering economy, reliability and voltage quality, and the calculation methods of different indexes are presented. This paper puts forward an improved triangular fuzzy number analytic hierarchy process (ITFNAHP) to weight the second level indexes (SLI) and the third level indexes (TLI), and calculates the variation coefficient to weight the fourth level indexes (FLI). We calculate the comprehensive weight coefficients based on the weight coefficients of the SLI, TLI and FLI, and then calculate the comprehensive evaluation of satisfaction (CES) of different access schemes. On the basis of the IEEE 33-bus example system, simulations of the calculation methods and the comprehensive evaluation method are carried out under different DG access schemes according to the same total investment cost and the same permeability, respectively, and the simulation results are analyzed and discussed.

• Biomolecules & Therapeutics
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• 제15권2호
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• pp.102-107
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• 2007

Cimetidine, a substrate for P-glycoprotein (P-gp), is a well known drug interacting with a variety of drugs and results in alteration of pharmacokinetic parameters by concomitant administration. The aim of present study was to investigate whether cimetidine affects the transport of various quinolone antibiotics in human colorectal cancer cell line (Caco-2) system which has been typically used to investigate drug transport via P-gp. The apparent permeability coefficients (P$_{app}$) value of 9 quinolone antibiotics in the co-treatment with cimetidine was examined. Apical to basolateral (AP-to-BL) transport of fleroxacin in the co-treatment with cimetidine was increased to 1.5-fold (p<0.01) compared with that of fleroxacin alone, whereas basolateral to apical (BL-to-AP) transport of fleroxacin was decreased to 0.83-fold significantly (p<0.05). Ofloxacin was decreased to 0.8-fold (p<0.01) and 0.72-fold (p<0.01) significantly in AP-to-BL and BL-to-AP direction, respectively by cimetidine cotreatment. The P$_{app}$ values of gatifloxacin, moxifloxacin, ciprofloxacin and rufloxacin also were changed by cimetidine. These results have a potential that cimetidine influences on the pharmacokinetics of quinolone antibiotics. It suggests that careful drug monitoring and dosage adjustment may be necessary during the co-administration of quinolone antibiotics with cimetidine.