• 대한토목학회논문집
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• 제6권3호
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• pp.43-51
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• 1986

시료토(試料土)의 입경(粒經), 밀도(密度), 주입재(注入材)의 농도(濃度)를 변화(變化)시켜 불투수성(不透水性) 공시체(供試體)를 만들어 삼축압축시험(三軸壓縮試驗)에서 수직응력(垂直應力), 구속압(拘束壓)(${\sigma}_H$) 및 주입속도(注入速度)의 변화(變化)에 따라 공벽주변(孔壁周邊)에서 종할열시(縱割裂時)에 간극수압(間隙水壓)을 측정하여 간극수압(間隙水壓)~구속압(拘束壓)~종할열주입압(縱割裂注入壓)(${\sigma}$)~인장강도(引張强度)(${\sigma}_t$)와의 상관관계(相關關係)를 구하였다. 연약점성토(軟弱粘性土)에서의 이와 같은 수압파쇄현상(水壓破碎現象)은 탄성론(彈性論)에 의한 이론치(理論値)보다 낮은 주입압(注入壓)에서 발생하는데 이것은 구속압(拘束壓)에 의한 간극수압(間隙水壓)($U_a$)과 주입압(注入壓)에 의한 간극수압(間隙水壓)($U_i$)의 영향임(影響)을 알 수 있었다. 따라서 종할열발생시(縱割裂發生時)의 주입압(注入壓)은 다음과 같이 수정(修正)함이 바람직하다. $${\sigma}=2{{\sigma}_H}-(U_a+U_i)+{\sigma}_t$$.

• 에너지공학
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• 제7권1호
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• pp.57-64
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• 1998

폴리에스터와 스테인레스스틸섬유를 재료로 제조된 제전사여과포에 대한 물리화학적 특성시험 및 여과포성능 기초시험을 수행하였다. 실험용먼지로 제철.제강, 시멘트제조, 열공급시설 및 폐기물공정에서 채취된 먼지를 처리하여 사용하였다. 제전사여과포의 물리화학적 특성 실험에서는 산성분위기하에서 인장강도 및 초기탄성계수변화를 조사하였고, Automated Permporometer를 이용하여 평균흐름세공압력, 기포점 세공지름, 평균흐름세공지름 및 세공크기분포를 구하였다. 또한 벤처규모의 여과포 기초성능 시험장치를 이용하여 먼지부하에 따른 압력손실, 먼지통과율 및 여과포성능 평가지표를 산출하였다. 산성가스 및 분위기하에서 제전사여과포의 인장강도는 온도 및 노출시간과 깊은 관련이 있었다. 압력손실은 여과속도와 먼지부하가 증가함에 따라 증가하였으며 증가형태는 먼지의 종류에 따라 달랐다. 먼지 통과율은 먼지종류에 관계없이 먼지부하의 증가에 따라 급격히 감소하는 경향을 나타내었다. 여과포성능지표는 먼지 포집 초기에는 증가했다가 급격히 감소하여 일정하게 유지되었다.

• 상하수도학회지
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• 제19권2호
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• pp.135-143
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• 2005

It was evaluated that the effect of turbidity removal by Pore Controllable Fiber Filter(PCF) installed in NS(Naksang) small water treatmant plant(system) using under flow water as raw water in the study. The results of the study are as the followings. Firstly, the removal efficiency of turbidity by PCF without coagulation(in operation mode not using coagulants) was mostly below 20 percent. On the other hand, when operation using proper coagulants, that of turbidity was mostly over 80 percent. Secondly, slow sand filtration after PCF, total turbidity removal efficiency of final treated water was 84.3 percent, and the contribution by PCF was 57.1 percent and that of slow sand filtration was 27.7 percent. Therefore the introduction of PCF as pre-treatment process would be helpful to reduce the loading of high turbidity of slow sand filtration. Thirdly, the results of particle counter measurements showed that when operated PCF with coagulants, fine flocs captured or adsorbed at the pore of PCF were flow out into the effluents from 120 minutes after backwashing because of the increase of headloss of PCF. Therefore the decision of backwashing time should made consideration into the outflow of fine flocs from PCF. Fourth, coagulant dosages on PCF at the same turbidity was largely variable because of the effect of the raw water characteristics and the turbidity increase velocity at rainy days, therefore flexible coagulant dosages should be considered rather than fixed coagulant dosage by the influent jar-test result.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4664-4670
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• 2010

본 연구에서는 기존 MIM Zone model과 새로이 유도한 모델과 비교를 통해 몇가지 결론을 도출하였다. MIM model 이 적용되면 immobile 영역에서의 초기농도는 기공의 형태에 의해 달라지는 보정계수에 의해 실제농도보다 저평가되었으며 이는 오직 확산이 기공의 가장 깊은 부분까지 시행된 이후에 유효함을 확인하였다. 물질이동계수, $\alpha$는 기공의 깊이에 따라 반비례하며, 유동 구역의 유속에는 종속되어지지 않는다. 기존의 MIM model 은 확산주도영역의 농도가 급속하게 감소하는 현상을 보여주는데 새로이 유도된 모델의 경우도 충분한 시간이 경과한후 비슷한 현상을 보였으며 이는 기존의 여러 실험에서 관찰된 power-law BTC 의 상반되는 결과를 보여준다.

• 한국재료학회지
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• 제16권8호
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• pp.516-523
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• 2006

In recent years, Magnesium (Mg) and its alloys have become a center of special interest in the automobile industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die-casting parts can be easily produced. The die casting process is a fast production method capable of a high degree of automation for which certain Mg alloys are ideally suited. In this study, step-dies and flowability tests for AM50 were performed by die-casting process according to various combination of casting pressure and plunger velocity. We were discussed to velocity effect of forming conditions followed by results of microstructure, FESEM-EDX, hardness and tensile strength. Experimental results represented that the conditions of complete filling measured die-casting pressure 400 bar, 1st plunger velocity 1.0 m/s and 2nd plunger velocity 6.0 m/s. The increasing of 2nd plunger velocity 4.0 to 7.0 m/s decreased average grain size of $\alpha$ phase and pore. It was due to rapid filling of molten metal, increasing of cooling rate and pressure followed by increased 2nd plunger velocity. The pressure should maintain until complete solidification to make castings of good quality, however, the cracks were appeared at pressure 800bar over.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 학술발표집 지반진동 영향평가
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• pp.1-14
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• 1993

Ground reinforcements is the essential method to prevent the liquefaction of loose sand deposit, However, in the construction of the life lines, it is impossible to treat the whole loose deposit against liquefaction. As an countmeasure for the life lines against the liquefaction, a monitorning system can be considered for an immediate judgement of the liquefaction occurrence during an earthquake. Through shaking table tests on model grounds, pore presure developments were investigated in terms of the surface spectral velocity, which was verified as a tool for the immediate judgement of the liquefaction occurrence.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.41-41
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• 2002

Tolaasin, a pore-forming 1.9 kDa peptide toxin released by Pseudomonas tolaasii, produces brown blotch disease on cultivated oyster mushrooms. To investigate the mechanism of tolaasin-induced cell disruption, we studied the effect of temperature on the hemolytic process. In the kinetic analyses, single exponential function was fitted to the data obtained from temperature-dependent velocity of hemolysis(1/t$\_$50/, implying that there is a major time-limiting factor on the temperature-dependent hemolysis.(omitted)

• Nuclear Engineering and Technology
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• 제16권2호
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• pp.80-88
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• 1984

Thriethylenediamine(TEDA)주입 활성탄층에 의한 공기중의 methyliodide 제거 메카니즘이 조사되었다. 실험 결과, 공기 유속이 20cm/sec 이상일 때는 기공확산이 율속 단계였으며, 10cm/sec 일때는 기공확산 저항과 외부 물질 전달 저항이 모두 총괄 물질 전달 저항에 기여하였다. 공기중 수증기가 존재하지 않는 건조 조건하에서의 TEDA 함침 탄소층의 성능을 묘사하기 위한 흡착 모델이 제안되었다. 계산된 값은 실험 결과와 잘 일치하였다.

• 한국세라믹학회지
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• 제40권8호
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• pp.735-738
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• 2003

고주파용 회로기판으로 사용하는 PTFE 복합체를 woven glass fiber를 사용하여 제조하였다. 유전상수는 PTFE 분산액에 woven glass fiber를 함침하는 횟수 증가에 따라 감소하는 특성을 나타내었으며, 3회 함침 횟수부터는 변화율이 감소하였는데, 이것은 PTFE 미세분말이 woven glass fiber의 기공과 굴곡 사이를 충분히 채우기 때문이다. 또한 함침 횟수 증가에 따라 PTFE의 비율이 증가하면서 유전 상수가 감소하여 회로 기판의 전파 전송속도는 증가하였다.

• 한국대기환경학회지
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• 제20권3호
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• pp.361-369
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• 2004

A metal fiber bed has seldom been applied to the practical filtration process despite its excellent mechanical and chemical stability. The filter-bed used in this work was highly porous with open structure, of which apparent porosity was 80 ∼ 90%. Although pressure loss across the filter-bed was very low, separation efficiency was found to be quite high. This paper focuses on the basic filtration mechanisms of a metal filter-bed and a thin ceramic filter from fly ash for reference. The experimental parameters were face velocity, dust loading and porosity of filter-bed. Pressure drop increased with increasing face velocity and dust feeding load for both filters. It also showed that dust particles deposited in the deep flow path, finally resulting in clogging the pore channels. It thereby indicates that the dominating mechanism of the metal filter-bed would be depth filtration. Meanwhile, the thin fly ash composite filters trapped the aerated dust mainly on the surface of the filter medium, so that the instantaneously formed dust layer might cause a steep increase of pressure drop across the filtration system.