• 자원환경지질
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• 제32권1호
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• pp.43-51
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• 1999

In order to remediate hazardous waste site, a process of electrokinetically purging chemicals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes that habe igh removal efficiency and time-effectiveness in low-permeability soils such as clay. Being combined with several mechanisms-electromigration, elec troosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. The objectives of this study are; 1) the exploration of the feasibility of electrokinetic soil processing on the removal of heavy metals, 2) the investigation of applicability to the tailing-soils in aban doned mining area, 3) the examination of effects of soil pH and conductivity on the transport phenomena of elements in soils, and 4) the investigation of the applicability of the ionexchange membrance to the efficient collection of heavy metals removed from contaminated soils. With the result of this study, it is suggested that the removal efficiency is significantly influenced by applied voltage & current, type of purging solutions, soil pH, permeability and zeta potentials of soil. Although further study should be needed, it is possible to collect removed heavy metals with ion-exchange membrance in cathode compartment.

• Computers and Concrete
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• 제23권5호
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• pp.351-359
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• 2019

In this study, the calcium hydroxide, an inherent product of cement hydration, was treated using biomimetic carbonation method of incorporating stearic acid to generate the hydrophobic calcium carbonate on concrete surface. Carbonation reaction was carried out at various $CO_2$ pressure and temperatures and utilizing the Scanning Electron Microscope (SEM), chloride-ion penetration test apparatus, and compression test machine to investigate the hydrophobicity, durability, and mechanical properties of the synthesized products. Experimental results indicate that the calcium stearate may change the surface property of concrete from hydrophilicity to hydrophobicity. Increasing reaction temperature can change the particles from irregular shapes to needle-rod structures with increased shear stress and thus favorable to hydrophobicity and microhardness. The contact angle against water for the concrete surface was found to increase with increasing $CO_2$ pressure and temperature, and reached to an optimum value at around $90^{\circ}C$. The maximum static water contact angle of 128.7 degree was obtained at the $CO_2$ pressure of 2 atm and temperature of $90^{\circ}C$. It was also found that biomimetic carbonation increased the permeability, acid resistance and chloride-ion permeability of the concrete material. These unique results demonstrate that the needle-rod structures of $CaCO_3$ synthetized on concrete surface could enhance hydrophobicity, durability, and mechanical properties of concrete.

• 멤브레인
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• 제33권5호
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• pp.233-239
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• 2023

VRFB에 사용되는 막의 수송 능력은 배터리 성능에 필수적인 요소이다. 탁월한 배터리 성능을 위해서는 높은 양성자 전도도와 낮은 바나듐 이온 투과도가 달성되어야 한다. 하지만 양성자 전도도와 바나듐 이온 투과도 사이에는 상충관계가 존재한다. 따라서 이 상충관계를 해결하는 것이 VRFB의 발전에 필수적이다. 또한 높은 쿨롱 효율, 전압 효율 및 에너지효율을 유지하는 것이 고성능 VRFB를 위해 필수적이다. 최근 복합막과 SPEEK 막을 중심으로 나피온 막의 기존 한계를 극복하기 위한 다양한 시도가 이루어지고 있다. VRFB은 이 논문에서 검토하는 복합막에서 충전식 배터리의 필수 등급이다.

• 한국잡초학회지
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• 제5권1호
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• pp.85-88
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• 1985

본(本) 실험(實驗)은 신종(新種) 제초제(除草劑)인 CGA 82725와 DOWCO 453의 살초기구중(殺草機構中) 하나의 기작(機作)으로 사료(思料)되는 세포막투과성(細胞膜透過性)에 미치는 영향(影響)을 조사(調査)하였다. 1. CGA 82725는 $10{-3}M$ 농도(濃度)에서 세포막투과성(細胞膜透過性)으 증가(增加)시켰다. 2. DOWCD 453은 $10^{-2}M$ 농도(濃度)에서 세포막투과성(細胞膜透過性)을 증가(增加)시켰다. 3. Paraquat와 Dinoseb은 $10^{-5}M$과 $10^{-4}M$에서 세포막투과성(細胞膜透過性)을 증가(增加)시켰다. 4. 세포막투과성(細胞膜透過性) 증가(增加)와 잎에 나타나는 necrosis 현상(現象)과는 항상 일치(一致)하지는 않는다.

• 한국건축시공학회지
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• 제16권6호
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• pp.479-485
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• 2016

콘크리트용 천연골재의 공급이 어려워지고 건설폐기물은 발생량이 지속적으로 증가하고 있는 추세이다. 따라서 건설폐기물을 골재로 만든 순환골재 사용의 필요성이 대두되고 있다. 이에 순환골재를 사용한 콘크리트의 특성에 대한 많은 연구가 진행되고 있으나 대부분의 연구들이 부정적인 결과를 나타내고 있다. 하지만 최근 연구들을 중심으로 긍정적인 연구결과들이 보고되고 있으며 그 중 순환굵은골재의 부착 모르타르의 염화물고정효과에 관한 연구도 보고되고 있다. 따라서 본 연구에서는 순환굵은골재에 비해 모르타르 함량이 많아 염화물고정에 유리하다고 예상되는 순환잔골재를 사용한 모르타르의 역학적 특성과 염화물확산을 평가한 결과 순환잔골재의 염화물고정효과를 확인했다.

• 대한수의학회지
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• 제32권4호
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• pp.543-553
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• 1992

Properties of unitary ATP-sensitive $K^+$ channels were studied using planar lipid bilayer technique. Vesicles were prepared from bullfrog (Rana catesbeiana) skeletal muscle. ATP-sensitive $K^+$ (K (ATP)) channels were identified by their unitary conductance and sensitivity to ATP. In the symmetrical solution containing 200mM KCI, 10mM Hepes, 1mM EGTA and pH 7.2, single K (ATP) channels showed a linear current-voltage relations with slight inward rectification. Slope conductance at reversal potential was $60.1{\pm}0.43$ pS(n=3)). Micromolar ATP reversibly inhibited the channel activity when applied to the cytoplasmic side. In the range of -50~＋50 mV, the channel activity was not voltage-dependent, but the channel gating within a burst was more frequent at negative voltage range. Varying the concentrations of external/internal KCl(mM) to 40/200, 200/200, 200/100 and 200/40 shifted reversal potentials to $-30.8{\pm}2.9$(n=3), $-1.1{\pm}2.7$(n=3), 10.5 and 30.6(mV), respecrivety. These reversal potentials were close to the expected values by the Nernst equation, indicating nearly ideal selectivity for $K^+$ over $Cl^-$. Under bi-ionic conditions of 200mM external test ions and 200mM internal $K^+$, the reversal potentials for each test ion/K pair were measured. The measured reversal potentials were used for the calculation of the releative permeability of alkali cations to $K^+$ ions using the Goldman-Hodgkin-Katz equation. The permeability sequence of 5 cations relative to $K^+$ was $K^+$(1), $Rb^+$(0.49), $Cs^+$(0.27), $Na^+$(0.027) and $Li^+$(0.021). This sequence was recognized as Eisenman's selectivity sequence IV. In addition, modelling the permeation of $K^+$ ion through ATP-sensitive $K^+$ channel revealed that a 3-barrier 2-site multiple occupancy model can reasonably predict the observed current-voltage relations.

• Journal of Pharmaceutical Investigation
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• 제26권1호
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• pp.43-53
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• 1996

The objective of this study was to determine whether 4-phenylazobezyloxycarbonyl-Pro-Leu-Gly-Pro-D-Arg (Pz-peptide), an enhancer of hydrophilic solute permeability in the intestine, could elevate the paracellular permeability of hydrophilic drugs across cornea and conjunctiva in the rabbit. The in-vitro penetration of hydrophilic drugs (mannitol, atenolol) and lipophilic drug (propranolol) across the rabbit cornea and conjunctiva was studied either in the presence or absence of 3 mM Pz-peptide. Drug penetration was evaluated using the modified Ussing chamber. The conjunctiva was more permeable than the cornea to all drugs. Pz-peptide showed enhanced effects on the drug transport across cornea and conjunctiva in a concentration dependent manner. Effects or ion transport inhibitor on the mannitol penetration were then investigated. Mannitol penetration was not changed by serosal addition of $100\;{\mu}M$ ouabain, suggesting that $Na^+/K^+$ ion tranporter was not involved in the Pz-peptide induced elevation of paracellular drug permeability. Furthermore, effects of Pz-peptide and EDTA on the transport of atenolol and propranolol into the ocular tissues or blood circulation after its administration into both eyes were investigated. EDTA showed enhanced effect on propranolol transport into the ocular tissues, but Pz-peptide did not show significant difference. Systemic absorption of propranolol by the addition of EDTA or Pz-peptide was not changed. On the other hand, EDTA and Pz-peptide elavated the atenolol transport into the ocular tissues. The transport of atenolol into the blood circulation was also enhanced by the addition of EDTA, but no effect was observed by the addition of Pz-peptide. The above findings suggest that Pz-peptide would be used as an paracellular pathway enahncer of hydrophilic drugs into the eye, without affecting the systemic absortion of topically applied opthalmic drugs.

• 멤브레인
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• 제14권2호
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• pp.108-116
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• 2004

본 연구에서는 비대칭 polyvinylidene fluoride (PVDF)막을 기질막으로 하여 Pore-filled 이온교환막을 제조하였다. 먼저 다공성 PVDF막의 기공에 80%의 chloromethylate aryl ring을 가지고 있는 poly(vinylbenzyl chloride) (PVBCI)과 1,4- diaminobicyclo［2,2,2］octane (DABCO)을 tetrahydrofuran (THF)와 dimethylforamide (DMF)가 8:2로 혼합된 용액에 녹여서 채워 넣고 겔화시킨 후, 남아 있는 chloromethyl group에 trirnethylamine (TMA, 40 wt% in water)을 이용하여 양이온 암모니움 site를 형성시키면 pore-filled 음이온교환막이 형성된다. 이와 같이 2단계의 제조 방식으로 제조된 pore-filled 막은 크기의 변화가 없으며, 가교도의 조절로써 최종 막의 특성이 간단하게 조절되는 것을 보여주었다. SEM과 AFM의 표면촬영의 결과로부터 기질막의 기공 내에 고분자겔의 존재를 확인하였다. 투과도와 배제율에 많은 영향을 미치는 용매를 조사한 결과 tetrahydrofuran (THF)만을 사용하여 제조한 막보다 THF와 DMF를 함께 사용할 때 더 우수한 막이 제조되었다. 제조된 최종 막의 수투과도 조사결과, 가교도 10% 막의 경우 아주 낮은 압력에서(100 Kpa) 전형적인 한외여과막의 투과도(8∼10 kg/$m^2$hr)를 보여주었으며 배제율 또한 우수한 결과(55∼60%)를 보여주었다. 압력에 대한 pore-filled 이온교환막의 성능을 관찰한 결과 압력이 증가할수록 투과도와 배제율은 함께 증가하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.553-556
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• 2006

Generally, concrete is one of the most widely used construction materials, because of its good durability to cost ratio. However, when subjected to severe environments its durability can significantly decline due to various harmful conditions. In this article, we would like to investigate a chloride ion diffusion of cement matrix with inert filler, which ground calcium carbonate(GCC). For the experimental results of the chloride ion diffusion, as the addition of GCC makes decreasing the permeability by micro-filler effect, the matrix of 5-15% ratio of replacement are superior to the GCC0 mortar matrix with respect to durability of cement matrix in this scope.

• 대한화학회지
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• 제20권6호
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• pp.448-452
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• 1976

간단한 통계역학적 방법을 사용 수화된 이온의 완화시칸, 탈수화시의 활성화, 에너지, 탈수화율 등을 계산하였다. 구상한 model에 의하면 수화된 물과 탈수화된 물 간의 평형상수, 물-이온간 에너지 항, 각종 species 간의 혼합 factor들이 들어있다. 이론과 실험은 잘 맞는 겨로가를 보이고 있다. 또한 이온이 탈수화식의 압력의 영향도 아울러 논의하였다.