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        검색결과 456

        441.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        지표-지각환경을 구성하는 지질매체의 구조와 성질의 정량적-체계적 이해를 위한 예비연구로, 매질을 구성하는 입자의 모양, 크기, 충전 밀도가 공극 구조의 특성과 매질의 성질에 미치는 영향을 알아보기 위해 입자의 모양이 구형인 글래스 비드와 모양이 불규칙한 실리카 젤을 이용하여 입자 크기와 공극률이 서로 다른 다양한 다공성 매질을 준비하였고, 핵자기공명 현미영상을 이용하여 약 50 μm의 분해능으로 삼차원 영상을 획득하였다. 분석 결과, 지름 약 0.2~1.3 mm 크기의 입자로 구성된 다공성 매질의 비표면적은 2.5부터 9.6 mm2/mm3, 공극률은 0.21에서 0.38, 투수율은 11.6에서 892.3 D이며, 이는 일반적인 미고결 샌드가 갖는 값의 범위에 해당된다. 비표면적, 공극률, 투수율의 관계는 Kozeny 식에서 예상된 경향과 비교적 일치하였다. 상자집계 프랙탈 차원은 공극률, 비표면적과의 관련성이 높으며, 공극률이 0.29~0.38일 때 비표면적이 약 2.5부터 6.0 mm2/mm3까지 증가할수록 프랙탈 차원이 2.6에서 3.0까지 선형으로 증가하며, 공극률이 0.21~0.28일 때 비표면적이 약 2.5부터 9.6 mm2/mm3까지 증가할수록 프랙탈 차원이 2.5에서 3.0까지 선형으로 증가한다. 실제 다공성 사암에 포함된 유체의 삼차원 구조를 핵자기공명 현미영상으로 영상화하였고, 이에 대한 비표면적은 0.33 mm2/mm3, 공극률은 0.017, 투수율은 30.9 mD, 상자 집계 프랙탈 차원은 1.59로 계산되었다. 본 연구에서 제시된 것과 같이 핵자기공명 현미영상은 다양한 다공성 매질의 삼차원 공극 구조를 영상화할 수 있고, 삼차원 공극 구조에 대한 상자집계 프랙탈 차원은 본 연구에서와 같이 다양한 공극 구조에 대해 분석이 가능하며, 다공성 매질의 이동 특성을 나타내는 매개 변수들과 지진파 감쇠 등에 대한 조절 인자로 사용될 수 있을 것으로 기대된다.
        442.
        2009.09 KCI 등재 서비스 종료(열람 제한)
        The vegetated porous pavement can be installed as an alternative way to replace the traditional pavement, which contributes less to the water circulation system in the urban area. This study aims to an investigation based on the shadow and pressure of the vehicle system, where the turfgrass get grown and the green block get constructed on the grassy parking lot. This study might achieve these conclusions, in the case of use ‘green block’ makes grass parking lot, plant a kind of ‘zenith’ and takes sod thickness 40 mm are more efficient for turfgrass growth in the early times. In the case of parking over 8 hours in a day, after 5 weeks turfgrass growth would come into reduce. So over 4 hours parking and after 9 weeks, we need consider to setting up green block in grassy parking lot. The grassy ground would get pressured by the vehicles’ load and it would bring into some damage due to the load after 3 weeks. So we should put the grass’s growth root point under the designed a top of ‘green block’ level. When the vehicle amounts and parking density is in a low level, it could be an environmentally friendly product.
        443.
        2006.11 KCI 등재 서비스 종료(열람 제한)
        Stormwater pollution is a major problem in urban areas. Pollutants like heavy metals and harmful chemicals in the runoff can endanger soil and ground water, when they are not sufficiently removed during infiltration. Strength and infiltration capacity of porous concrete are the major problems that must be considered if permeable pavement system are demanded to be used in a drive way application. In this study, a series of compacted porous concrete mixtures and the system of pavement are tested for the physical characteristics like compressive strength, flexural strength, unit weight, porosity, water permeability, and the purification capacity of contaminated water. The test results obtained indicate that the strength and infiltration capacity of porous concrete are strongly related to its matrix proportion and compaction energy and providing adequate filter layers underneath pavement surface course is one of the most important design considerations of permeable pavement system for pollution retention purpose.
        444.
        2006.05 KCI 등재 서비스 종료(열람 제한)
        The strength, water permeability, and photo-degradation efficiency of NOx of porous concrete with a new concept were studied in this paper. The porous concrete was comprised of coarse aggregate of maximum size 40 mm, cement, silica fume, water and air-entraining(AE) water reducing agent. The strength of porous concrete was strongly related to its matrix proportion and compaction energy. An experimental test was carried out to study the parameters of cement proportions and silica fume content for pavement applications of porous concrete which were paving a footpath, a bikeway, a parking lot, and a driveway. The regressed equations of relationships between compressive strength and flexural strength, and coefficient permeability and void ratios were indicated as y=7.69x+71.74 and y=0.42e0.28x. A method of making an air purification-functioning road, which was spraying a mixture of a photocatalyst, cement, and water onto the surface of the road, was suggested.
        446.
        2004.11 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 사각형형상 수중방파제에 의한 불규칙파의 반사에 대하여 수리모형실험과 수치모형실험을 수행한 후 실험결과를 비교하였다. 수치해석 모형에서는 Reynolds 방정식을 지배방정식으로 사용하고 난류해석을 위해 k-모델을 적용하였으며, 자유수면변위를 추적하기 위해 VOF기법을 사용하였다. 수리모형실험과 수치모형실험의 결과는 서로 잘 일치하였으며, 수중방파제의 배열이 증가함에 따라 반사율은 증가하였다.
        447.
        2004.09 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 사각형 형상 불투과성 수중방파제를 통과하는 불규칙파의 반사를 고유함수전개법을 이용하여 해석하였으며, 수리모형실험 결과와 비교하였다. 불규칙파는 다수의 규칙파의 중첩으로 구성하였으며, 각각의 규칙파의 해석결과를 합성하여 반사율을 산정하였다. 고유함수전개법에 의한 해석결과는 수리모형실험에 의한 결과와 잘 일치하였으며, 불규칙파 역시 Bragg 반사 조건에서 공명현상에 의해 반사율이 크게 증폭되었다.
        448.
        2004.03 KCI 등재 서비스 종료(열람 제한)
        An experimental study on the preparation of monolithic porous polymers by environmentally friend process in supercritical carbon dioxide has been carried out. Polymerization mixture composed of a cross-linking monomer, initiator and functional co-polymer was charged in the reactor with sapphire window. After the system was purged with a flow of CO2 for 15 min, the reactor was pressurized with liquid CO2 up to 100 bars. The reactor was isolated from and placed back to the system via quick connector for shaking until the mixture had become fully homogeneous. The reactor was then heated and pressurized to the required reaction conditions and left overnight. After cooling and CO2 evacuation, the polymer was removed from the reactor as dry, white, continuous monoliths. The effect of experimental conditions on the physical properties of porous polymer was systematically examined, and it was found that monomer content had a major effect on the physical properties of the polymers.
        449.
        2003.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 최근 환경재료로서 관심이 모아지고 있는 다공성 콘크리트를 하천구조물(보 및 하상재료)에 적용함으로써 수질을 개선하고자 수행하였다. 먼저, 물리ㆍ화학적 특징을 평가해 본 결과, 공극률 10% 및 30%의 다공성 콘크리트의 압축강도는 일반 콘크리트의 최저 압축강도(180 kgf/)를 상회하여 하천구조물에 적용 가능하였고, 알칼리 용출에 의한 부착 미생물에의 영향도 거의 없을 것으로 판단되었다. 또한, 일반 콘크리트와 다공성 콘크리트로 하천구조
        450.
        2003.10 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 사다리꼴형상 투과성 수중방파제에 의한 정현파의 Bragg반사에 대해 수리모형실험과 수치모형실험을 수행하였으며, 두 실험결과를 비교하였다. 수치해석에 적용된 모형에서는 공간 평균된 Wavier-Stokes 방정식을 투과체 내에서의 지배방정식으로 사용하였고, 자유수면변위를 추적하기 위해 VOF기법을 적용하였다. 수리실험결과와 수치해석결과는 비교적 잘 일치하였으며, 투과성 수중방파제에 의한 반사계수는 불투과성에 비해 낮게 나타나고, 방파제의 배
        452.
        2000.12 KCI 등재 서비스 종료(열람 제한)
        Separation of strontium ion from synthetic seawater in the contained liquid membrane permeator with two micro-porous films was performed. The permeator consisted of a liquid membrane and two cells for aqueous solutions. The liquid membrane consisted of D2EHPA(di-2-ethylhexyl-phosphoric acid) and DCH18C6 (dicyclohexano-18-crown-6), diluted to 30 vol % with kerosine and was trapped between two micro-porous hydrophilic films. This liquid membrane separated two aqueous solutions, one of which was synthetic seawater and the other of which was the stripping solutions consisting of 1㏖/L H2SO4 Solution. The effects of various operating parameters on the extraction rate and equilibrium extraction ratio of strontium ion from synthetic seawater were experimentally examined. The addition of DCH18C6 to the D2EHPA solution caused synergy effect on the extraction of strontium ion. The permeator extracted strontium ion from synthetic seawater effectively with high membrane life time.
        453.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        For the purpose of development of a liquid membrane permeator which separates metal ions from aqueous solutions continuously and effectively, a continuous membrane permeator with the membrane solution trapped between extraction and stripping phases by two micro-porous hydrophilic films was manufactured. Experimental researches on the separation of zinc ion from aqueous solutions were performed in the liquid membrane permeator with 30 vol % D2EHPA solution in kerosine as liquid membrane. As results, the liquid membrane permeator separates zinc ion from aqueous solutions continuously and effectively in the wide range of operating conditions. A simple mass transfer rate model using equilibrium constant of the extraction reaction for the system used were proposed, and the model was compared with experimental results of separation of zinc ion in the permeator. And the effects of operating factors, such as space time, pH of extraction solution, extraction temperature, on the separation rate of zinc ion in the permeator were experimentally examined.
        455.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        유사매질개념에 의하여 비균질 다공성 매질을 설명할 수 있는 기존의 방법은 미시 밀러 상사(Mis), 거시 밀러 상사(MaS)와 웨릭 상사(WS)로 나눌 수 있고, 그들간의 관계는 MiS ⊂ MaS⊂ WS(⊂: subset)임을 알 수 있었다. 본 연구에서 제안한 방법은 WS에서 축적변수 =w 로 가정하고 함수량을 포화도 대신 유효포화도로 축적한 것이다. 이 방법은 검사해석의 관점에서 일반성이 결여되지 않고, 축적변수 만으로 비균질 매질을 설명할 수 있다
        456.
        1996.02 KCI 등재 서비스 종료(열람 제한)
        The combined wastewater of municipal landfill leachate and municipal sewage was treated using several sets of bench-scale aerated circulating system including porous media. Investigated items in this experiment were the dominant protozoa and metazoa in this system, the variation of microfauna relationship between operating condition and dominant genera. Also considered the factors determining dominant genera and their role. The outcome of this research is as follows; 1. Aspidisca, Vorticella, Trachellophyllum, Lecane, Philodina, Cyclops were mainly appeared prior to combinding leachate, while Trachelocerca, Bodo, Glaucoma were the dominant genera after combinding leachate. 2. As to metazoa, Nematode and Philodina were not influenced by 5% leachate mixing ratio, meanwhile Crustacea has high sensitivity for increased leachate mixing ratio and it was not appeared in 5% leachate mixing ratio. 3. The appropriate treatability could`nt be expected at the above 10% leachate mixing ratio. Especially, in the condition of 20% leachate mixing ratio, all of the microfauna were affected damage seriously on their existence. Meanwhile hydraulic retention time, substrate loading rate and sludge production rate didn`t give notable influence on increasing the number of microfauna. 4. As to protozoa, saprozoic and holozoic species were appeared commonly and polysaprobic species were dominent. 5. Filamentous organsms were nearly not affeced by leachate mixing. It seems that they could live without any trouble at the 10% leachate mixing ratio, if the substrate is sufficient. 6. Diversity of microfauna had a reducing trernd as the sewage was mixed with leachate.
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