• Journal of Pharmaceutical Investigation
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• 제36권5호
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• pp.321-329
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• 2006

Albuterol, a selective ${\beta}_2$-adrenergic receptor stimulant, has been introduced as a potent bronchodilator for patients with bronchial asthma, chronic obstructive bronchial disease, chronic bronchitis and pulmonary emphysema. The percutaneous permeation of albuterol sulfate was investigated in hairless mouse skin in vitro with and without pretreatment with enhancers. The enhancing effects of ethanol and various penetration enhancers such as terpenes, non-ionic surfactants, pyrrolidones, and fatty acids on the permeation of albuterol sulfate were evaluated using Franz diffusion cells. Among terpenes studied, 1,8-cineole was the most effective enhancer, which increased the permeability of albuterol sulfate approximately 33-fold compared with the control without enhancer pretrement, followed by d-limonene with enhancement ratio of 21.79. 2-Pyrrolidone-5-carboxylic acid increased the permeability of albuterol sulfate approximately 5.5-fold compared with the control. Other pyrrolidones tested showed only slight permeability enhancing effect with enhancement ratio less than 2.8. Nonionic surfactants showed moderate enhancing effects. Lauric acid increased the permeability of albuterol sulfate approximately 30-fold with decreasing the lag time from 2.85 to 0.64 hr. Oleic acid and linoleic acid showed enhancement ratio of 24.55 and 22.91, respectively. These findings would allow a more rational approach for designing formulations for the transdermal delivery of albuterol sulfate and similar drugs.

• 한국지반공학회지:지반
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• 제10권4호
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• pp.5-16
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• 1994

포항지역의 이암풍화토에 관한 공학적특성에 대하여 연구하였다. 토립자의 파쇄는 토립자의 표면적비로 나타냈다. 다짐시 함수비와 다짐에너지의 변화가 입도, CBR, 팽창성, 간극비 그리고 투수성에 미치는 영향에 대하여 연구하였으며, 그 결과는 다음과 같다. 1. 일반적으로 이암풍화토의 비중은 매우 작으며, 최적함수비는 크고 최대건조밀도는 작다. 2. CBR값은 다짐에너지의 증가에 따라 증가하나, D-2다짐(26kg.cm/cm3)이상에서는 오히려 감소하는 경향을 나타냈다. 팽창비는 다짐에너지 20.6kg.cm/cm3에서 최대가 되며 그 이상의 다짐 에너지에서는 감소하는 경향을 나타냈다. 3. 다짐에너지가 작을수록 함수비에 따른 투수성의 변화가 크다. 그리고 최소투수계수와 최적 함수비일때의 투수계수는 차이가 컸으나 다짐에너지가 증가할수록 그 차이는 거의 없었다. 4. 다짐에너지의 증가에 따른 입자의 파쇄는 간극비의 감소 그리고 표면적비의 증가와 그에 따른 투수계수의 감소가 나타났다. 특히 다짐에너지가 작을수록 표면적 비와 투수계수의 변화폭은 컸다.

• 한국해양공학회지
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• 제4권1호
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• pp.71-80
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• 1990

We experimented the physical property of the porous concrete by changing the water cement ratio, when the aggregate ratios are 1:5 and 1:7 separately. And then we received the results as follows. The bigger, the coarse grading of the porous concrete is, the more sensitive to the water cement ratio, the porous concrete becomes. And if we think over its compressive strength, the coarse aggregate which has 5-15mm width is most appropriate. So we concluded that when its compressive strength, permeability coefficient and its unit weight are $50kg/cm^{2}3cm/sec$ and $1900kg/m^{3}$ respectively, the water cement ratio which has 35-37% width is most appropriate, too. And its compressive strength and unit weight show that they are about a quarter and three quarters respectively about the conventional concrete.

• 한국지반환경공학회 논문집
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• 제3권3호
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• pp.15-25
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• 2002

투수계수는 연약점토의 기본 공학 특성 중 하나로서, 투수계수 값은 점토의 압밀과정뿐만 아니라 토양 내 오염물질의 이동에도 관계된다. 일반적으로 압밀이 진행되는 동안 간극비의 감소로 인해 점토의 투수계수 값은 감소하게 된다. Kozeny와 Carman 이후의 많은 연구자들이 다음의 관계로 간극비와 투수계수의 관계를 제안하였다. (1) log e - log k(1+e), (2) e - log k, (3) log e - log k. 본 연구에서는 대표적 국내 해성점토인 김해점토와 군산점토에 대하여 일정변형률(CRS) 압밀시험 수행하였다. 시험결과로부터 위의 관계식들은 군산점토와 김해점토에 모두 적용 가능한 것으로 나타났으며, 김해점토의 경우 경험적 관계식인 $C_k=0.5e_o$를 잘 만족하고 있으나 군산점토의 경우는 그렇지 않은 것으로 나타났다.

• 한국농공학회논문집
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• 제46권1호
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• pp.35-40
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• 2004

This study is performed to examine the physical and mechanical properties of eco-concrete using soil, natural coarse aggregate, excellent soil compound and polypropylene fiber. The test result shows that mass loss ratio is decreased with increasing the content of coarse aggregate and excellent soil compound. The compressive and flexural strengths are increased with increasing the content of coarse aggregate, excellent soil compound and polypropylene fiber. The coefficient of permeability is decreased with increasing the content of coarse aggregate and excellent soil compound, but it is increased in 0.2% polypropylene fiber content. The lowest coefficient of permeability is showed in $5.066\times 10^{-9}$cm/s. These eco-concrete can be used for farm road.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.227-230
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• 1998

The void ratio, continuous void ratio, coefficient of permeability, compressive strength and tensile strength were considered according to the EAF(Electric Arc Furnace) slag replacement and sand percentage in permeable concrete used with EAF slag as aggregate. The sand percentage was directly proportional to the permeable coefficient, but inversely proportional to the compressive strength. When the compressive strength and coefficient of permeability were 230 kg/$\textrm{cm}^2$ and 1$\times$$10^{-1}$ cm/sec, the useful sand percentage was 8%. When the EAF slag replacement was 25%, the coefficient of permeability was the most low and compressive strength was the most high.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.248-252
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• 2005

Compressibility and deformability of clays change greatly when the clays are subjected to disturbance. These tendencies have been studied. However, the effect of the disturbance on the permeability that consists of consolidation properties has not yet been studied. In this study, relationship between permeability and volume ratio under the different degree of disturbance are experimently obtained. The results indicate that the relations are less influenced if the disturbance is less depending on the kind of soils.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.403-408
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• 2000

Hardened concrete contains pores of varying types and sizes, and therefore the transport of air through concrete can be considered. The rate of permeability will not only depend on the continuity of pores, but also on the moisture contents in concrete. In this paper, the effects of curing conditions and moisture content ratios on the carbonation and air permeability are investigated according to the accelerated carbonation test. The results are follows. 1) Compressive strength, carbonation velocity and air permeability are influenced by the moisture content and curing method. 2) The relationship between carbonation velocity coefficient and air permeability coefficient has been quite well established.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.805-812
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• 2009

Permeation water resulting in the reclaimed land of waste can possibly cause the second pollution, such as the underground water and environmental pollution. Accordingly, Liner layer has been installed in the reclaimed land of waste to block and purify permeation water and prevent this second pollution. The material used as Liner layer is the one for water resistance and that of less than permeability coefficient $1{\times}10^{-7}cm/sec$ is widely used. As it is very difficult to secure in bulk this natural clay with low permeability around the field, the suitable way to secure low permeable material is that we use blend with good watertighness by mixing it with natural soil which is spread in the site. While this mixed soil which can resist water is commonly used in the site, bentonite mixed soil which is widely used as Liner layer in the reclaimed land of waste is recognized in Liner and durability. In this study, the engineering characteristics of soil-bentonite mixed liner are investigated using the laboratory hydraulic conductivity and uni-axial strength tests. The soil used for the liner is the clay soil located near the site. Mixing ratio of the bentonite which satisfies the requirement of hydraulic conductivity is determined and the optimum mixing ratio of bentonite is recommended for the landfill. After the mixed liner is constructed using the optimum mixing ratio of bentonite, the block samples of the constructed liner are obtained and the strength tests were performed. The hydraulic and strength properties of the liner for construction of the waste landfill were both satisfactory.

• 한국지반공학회논문집
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• 제18권5호
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• pp.229-236
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• 2002

본 논문은 실용화된 지반개량용 마이크로시멘트 및 보통포틀랜드시멘트의 주입특성에 관한 연구로서 기초물성, 고결율, 침투성과 같이 실험적으로 주입재의 입도와 다짐정도를 조정하고, 주입대상 토사지반의 투수계수를 3종류로 변화시컥 약액주입의 주요 특성을 검토한 것이다. 주입재의 적용성을 평가하기 위하여 고결성 시험 및 침투성 시험을 실시한 결과, 모형토사지반의 상대밀도에 따른 투수계수를 $10^{-4}$~$10^{-2}$cm/sec로 변화시킨 경우, 마이크로시멘트는 투수 계수 $10^{-4}$cm/sec에서 유효고결율 75%, 침투주입율 86%로서 침투성 및 고결성이 우수한 결과를 나타낸 반면, OPC는 $10^{-2}$cm/sec에서 유효고결율 및 침투주입율이 50% 미만으로서 원활한 침투주입이 될 수 없음을 알 수 있었다. 댐 기초 지반 및 연약지반의 보강을 위해 주입재의 침투성이 요구되는 경우에는 마이크로시멘트가 적용성이 매우 우수한 것으로 판단된다. 동수지중 모형시험 결과 유속이 상대적으로 느린 경우 주입압이 높을수록, 완결형 주입재가 고결효과가 우수한 반면, 유속이 빠른 경우에는 완결형의 경우 주입재의 대부분이 외부로 유출되는 등 유효고결율이 매우 낮아 고결효과가 불량함을 알 수 있었다.