• Journal of Adhesion and Interface
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• v.19 no.1
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• pp.50-54
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• 2018

• Journal of Adhesion and Interface
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• v.5 no.1
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• pp.12-20
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• 2004

Interfacial fracture mechanics is introduced and its application to adhesion measurement is reviewed. Various specimens are also introduced for the practical application.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.668-676
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• 2002

Especially, when orthotropic material such as uni-dierectionally woven Carbon Fiber Sheet, resisting only the unidirectional tension, is used to strengthening bridge deck, the direction and width of the strengthening material should be considered very carefully. Thus, analysis of the failure characteristics and the premature failure mechanism of the strengthened decks based on the test results are required. In this study, the premature failure due to the interface debonding of strengthening material of the strengthened deck slab are inquired into failure mechanism through both experiments results and analyses with prototype strengthened deck specimens using carbon fiber sheet. From the test results, interface debonding of strengthening material is occured at the crack face

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.310-310
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• 2013

본 연구에서는 Titanium (Ti) source/drain 전극 접합이 차세대 비정질 InGaZnO (IGZO) 기반 박막형 트랜지스터에 미치는 영향을 화학적, 구조적, 전기적 특성 분석을 통하여 관찰하고 Ti/IGZO 접합 특성을 설명할 수 있는 메커니즘을 제시하였다. IGZO 기반 박막형 트랜지스터 소자의 구동 특성은 transmission line method (TLM) 패턴 공정을 이용하여 정량적으로 분석되었다. 비정질 IGZO 기반의 박막형 트랜지스터에서 Ti source/drain 전극 접합에 의한 구동 특성 변화 및 영향을 확인하기 위하여 금속/산화물 계면 반응성이 낮은 silver (Ag) source/drain 전극이 reference로 비교되었으며, 그 결과 Ti source/drain 전극 접합이 적용된 비정질 IGZO 트랜지스터의 경우 Ti 금속과 IGZO 산화물 계면에 형성되는 열역학적으로 안정한 $TiO_x$ 층의 형성에 의해 VT ($-{\Delta}0.52V$) shift 및 saturation mobility ($8.48cm^2$/Vs) 상승됨을 확인하였다. 뿐만 아니라 TLM 패턴을 이용한 IGZO 트랜지스터의 전기적 변수 도출 및 수치적 해석으로부터 $TiO_x$ 계면층 형성이 Ti 금속과 비정질 InGaZnO 계면에서의 effective contact resistivity를 효과적으로 낮출 수 있음을 확인하였다. Ti source/drain 전극 접합에 의해 발생되는 $TiO_x$ 계면층의 화학적, 구조적 특성과 $TiO_x$ 계면층 생성에 의한 소자 특성 변화를 연관시켜 해석함으로써, IGZO 기반 박막형 트랜지스터에서의 Ti source/drain 전극 접합이 비정질 IGZO 기반 박막형 트랜지스터에 미치는 영향을 설명하였다.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.26-32
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• 2005

Surfactants can be used to enhance the mass transfer rate of hydrophobic compounds into the biologically active liquid phase, resulting in an increase in biodegradation rate of toluene. In this study, the mass transfer rate and the biocompatibility of toluene in the presence of various surfactants were evaluated. Four anionic and non ionic surfactants were tested: sodium dodecyl sulfate (SOS), TritonX-100, Tween 80, and BYK-345 (silicone surfactant). Experimental results showed that BYK-345 at the critical micelle concentration (CMC) enhanced the solubility of toluene. However, there was no increase in the solubility of toluene by SOS and TritonX-100 at their CMCs. With the addition of each surfactant into deionized water the mass transfer rate became faster than that of the case with no surfactant. A bottle study using toluene-degrading microorganisms showed that SOS seriously reduced toluene removal presumably due to the toxicity of the anionic surfactant and/or the substrate competition between the surfactant and toluene. In addition, the degradation rate of toluene was decreased in the presence of BYK-345, indicating that BYK-345 adversely affects the activity of microorganisms. However, TritonX-100 and Tween 80 did not decrease the degradation rate of toluene significantly. Rather, at the low concentration of TritonX-100 toluene degradation rate was even increased. Overall the experimental results suggest that TritonX-100 be the appropriate surfactant for enhanced biological degradation of toluene.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.296-301
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• 1995

For studying the role of acetone and surfactant in solution, and selecting the best surfactant for spray solution in herbicide screening, the solubilizability of 6 nonionic surfactant-acetone aqueous solutions to 18 herbicide technicals, their foliar wettability and phytotoxicity to soybean and rice plant were tested and evaluated. The solubilizability of surfactant-acetone aqueous solutions to herbicide technicals was dependent on the acetone content of solutions, and was less affected by nonionic surfactant. Foliar wettability of the surfactant solutions was good to soybean, but only polyoxyethylene lauryl ether HLB 13.6(LE-13.6) solution showed good wettability to rice plant within the concentration range of no phytotoxicity. Tween 20(0.1%), LE-13.6(0.01%) and polyoxyethylene nonylphenyl ether HLB 16.0(0.01%) solutions didn't induce phytotoxicity to soybean, and most of the surfactant solutions didn't induce phytotoxicity to rice plant. There was no surfactant that showed superior emulsifiability to various herbicide technicals, good foliar wettability to plants, and no phytotoxicity, but LE-13.6 was better than others.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.735-742
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• 2012

This study tried to find a suitable method for enhancing the foam stability of cationic surfactants that normally generate less foam or no foam. Several trials were made to enhance the foam stability: addition of anionic surfactant, colloids and polymer. Cationic starch (CA-ST) did not form foam at all, while the foam stability of two other cationic surfactant also showed low levels; methyl triethanol ammonium methyl sulfate distearyl ester (CEQ90) for 46 sec. and Cetyl trimethyl ammonium chloride (CM29) for 31 seconds. Foam stability of cationic surfactants were significantly affected by addition of anionic surfactant, sodium dodecyl sulfate (SDS). Foam stability of CA-ST was significantly enhanced by addition of SDS, while those of CEQ90 and CM29 were decreased. Addition of colloids ($SiO_2$, kaolin) and polyvinyl alcohol (PVA) enhanced foam stabilities of CEQ90 and CM29. However, CA-ST did not form foam even in the presence of colloids or PVA. Effect of simultaneous addition of colloids and anionic surfactant on foam stability of cationic surfactant showed that foam stability of cationic surfactant was more influenced by addition of anionic surfactant than colloids. Effect of simultaneous addition of PVA and anionic surfactant on the foam stability of cationic surfactant also showed that presence of anionic surfactant significantly affect the foam stability of cationic surfactant. Foam stability of CA-ST was greatly increased to 8,780 seconds by addition of SDS 0.14% and PVA 2.5%. The foam stability of CA-ST was 8 times higher than CEQ 90. This study suggested that cationic surfactants not forming foam can generate foam by addition of anionic surfactant and its stability can be additionally increased by addition of colloids and PVA. The study results showed that enhancement in foam stability of cationic surfactant was prominently affected by the concentration of anionic surfactant added.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.87-89
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• 1997

1. 서론 : 막을 이용한 분리기술의 실용화의 최대 과제는 선택성이 높고 용매의 투과용매의 투과속도가 높은 막재질 및 처리 면적이 큰 막의 개발이 필요하게 되었다. 이러한 성능 개발은 1960년대 cellulose acetate 계통의 막개발 이후 1980년대 지지층 고분자위에 다른 고분자 물질을 도포한 복합막(thin film composite layer)이 개발되어 막의 성능을 급격히 발전시켰다. 그 중에서 초박막화(ultrathin membrane)는 분리막에 의한 분리공정의 최대 결점인 낮은 투과량의 개선을 꾀할 수 있다는 장점 때문에 다양한 시도가 이루어지고 있다. 이러한 박막 제조 방법에는 박층분산법, 침지코팅법, 기상증착법, 계면중합법이 있으나, 섞이지 않는 두 계면 사이에서 고분자를 형성시키는 계면중합법은 수용상에 함침된 지지막위에 유기상을 계변에서 중합시켜 박막을 얻는 기술이다. 중합과정에서 일어나는 계면의 형성과정에 대한 연구는 미흡하기에 이에 본 연구는 시간에 따른 계면중합 반응 형성과정을 고찰하는 방법을 소개하고, 형성된 박막의 아론적, 실험적 두께 측정을 비교하였다.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.4
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• pp.473-479
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• 1994

보소계면활성제 없이 microemulsion을 형성하는 최적의 계면활성제 구조를 찾기 위한 일련의 연구 중 세번째로 propoxylated nonylphenol sulfates와 ethoxylated 혹은 propoxylated highly-branched tridecyl alcohol sulfates를 연구하였다. 온도, NaCl농도, 보조계면활성제 농도, ethylene oxide몰수(EON), propylene oxide몰수(PON) 등을 변인으로 하여 phase behavior 실험을 한 결과 tridecyl alcohol 친유기를 갖는 계면활성제가 보조계면활성제 없이 microemulsion을 형성하였다. $C_{13}O(EO)_mPO)_nSO_3Na$ 일반식으로부터 m과 n을 변경시킴으로써 계의 다양한 조건을 만족시키는 계면활성제를 디자인할 수 있었다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.137-139
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• 1998

계면활성제는 섬유, 의약품, 화장품, 식품, 조선, 토목, 건축, 광업, 가정용 세제 등 인간생활에 폭넓게 이용되고 있다. 계면활성제의 사용범위가 넓어짐에 따라 계면활성제 자체의 오염성 때문에 분리대상 물질이나 재사용을 위한 회수물질로 간주되고 있다. 특정물질의 분리$\cdot$회수를 위한 분리막 기술은 공정이 간단하고 상변화를 수반하지 않으므로 에너지 소모가 작은 장점들을 가지고 있어 폐수처리, 수처리, 대기오염 방지등에 이용되고 있다. 본 연구에서는 비교적 소수기가 짧아서 저온에서도 잘 녹고, 세정성이 양호하여 세제, 유화제, 섬유제품의 침투제로 널리 이용되고 있는 음이온 계면활성제 SDS와 SLS용액의 한외여과에 대한 투과실험을 수행하였다. 또한 음이온 계면활성제와 인체에 유해한 금속이온($Cd^{++}, Cu^{++}, Zn^{++}$) 혼합물에 대한 제거실험을 실시하였다.