• Computers and Concrete
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• 제17권1호
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• pp.53-66
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• 2016

Currently, most of the investigations on chloride diffusion were based on the experiments and simulations concerning single cation type chlorides. Chloride diffusion associated with dual or multi cation types was rarely studied. In this paper, several groups of diffusion experiments are conducted using chloride solutions containing single, dual and multi cation types. A multi-ionic model is also proposed to simulate the chloride diffusion behavior in the experimental tests. The MATLAB software is used to numerically solve the nonlinear PDEs in the multi-ionic model. The experimental and simulated results show that the chloride diffusion behavior associated with different cation types is significantly different. When the single cation type chlorides are adopted, it is found that the bound rates of chloride ions combined with divalent cations are greater than those combined with monovalent cations. When the dual/multi cation type chlorides are adopted, the chloride bound rates increase with the $Ca^{2+}/Mg^{2+}$ percentage in the source solutions. This evidence indicates that the divalent cations would markedly enhance the chloride binding capacity and reduce the chloride diffusivity. Moreover, on the basis of the analysis, it is also found that the complicated cation types in source solutions are beneficial to reducing the chloride diffusivity.

• 대한의용생체공학회:의공학회지
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• 제8권2호
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• pp.123-134
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• 1987

The transport phenomena of alkali metal chlorides through poly(2 hydroxyethyl methacrylate) hydrogel membrane have been studied using electrodialysis. The hydrogel membranes were prepared by the polymerization of 2-hydroxvethyl methacrylate in the presence of 45%(V/V) H2O and ethyleneglycodimethacrylate. The initiator used in the polymerization was azobismethylisobutyrate (AMIB) prepared from azobisiobtyronitrile (AIBN) using Mortimer method. The permeability of alkali metal chlorides such LiCl, NaCl and KCI at 50 voltage was obtained. The permeability of NaCl was also observed at 30, 40, 50, and 60 voltages respectively. The concentration of solutes permeated through the membrane was measurer by flame photometry. The experimental results have been discussed with the comparison of apparent solute molecular size, the self-diffusion coefficient of solutes, the transport number of cations in aqueous solution. These indic aloes that poly(2 hydroxyethyl methacrylate) hydrogel membrane shows a specific selectivity for sodium ion.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.33-39
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• 1999

This study was conducted to confirm the effect of bypass dust on the hydration and mechanical properties of the cement pastes and mortar obtained from ordinary Portland cement (OPC), OPC-slag and OPC-fly ash system. The rate of heat evolution is accelerated with the content of By-pass Dust(BD). total heat evolution increased because alkali-chlorides activated the hydration of blended cement. Compressive strength and bound water content show maximum value at 5wt% By-pass Dust(BD) on each curing time in ordinary Portland cement and slag blended cement. Ca(OH)2 content of Ordinary Portland Cement increased as the content of BD and curing time. In blended cement, the formation of Ca(OH)2 is active at early hydration stage. By pozzolanic reaction, the content of Ca(OH)2 is decreased as curing time goes by. According to the BD content stable chlorides complex of Friedel's salt (C3A·CaCl2·10H2O) is created. Due to the hydration activation effect of chlorides and alkali we observed Type II C-S-H, which developed into densest microstructure.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.211.1-211.1
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• 2014

Recently, the scaling of conventional planar NAND flash devices is facing its limits by decreasing numbers of electron stored in the floating gate and increasing difficulties in patterning. Three-dimensional vertical NAND devices have been proposed to overcome these issues. Atomic layer deposition (ALD) is the most promising method to deposit charge trap layer of vertical NAND devices, SiN, with excellent quality due to not only its self-limiting growth characteristics but also low process temperature. ALD of silicon nitride were studied using NH3 and silicon chloride precursors, such as SiCl4[1], SiH2Cl2[2], Si2Cl6[3], and Si3Cl8. However, the reaction mechanism of ALD silicon nitride process was rarely reported. In the present study, we used density functional theory (DFT) method to calculate the reaction of silicon chloride precursors with a silicon nitride surface. DFT is a quantum mechanical modeling method to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. The bond dissociation energy of each precursor was calculated and compared with each other. The different reactivities of silicon chlorides precursors were discussed using the calculated results.

• 공업화학
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• 제17권3호
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• pp.286-290
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• 2006

새로운 4급 염화 암모늄염, {alkyldimethyl-[5-(2-phenylthiazol-4-yl]-1,3,4-oxadiazol-2-ylmethyl]quaternary ammonium chlorides (ADOQACs): 6}을 화합물 5와 몇 가지 N,N-dimethylalkyl amine을 반응시켜 합성하였다. 합성한 화합물들의 구조와 물리적 특성을 조사하였고 계면활성을 측정하였다. 화합물 6의 표면장력($\gamma_{cmc}$)과 최소저해농도(MIC)는 알킬기의 영향을 받은 것으로 나타났으며, 특히 화합물 6c와 6d가 좋은 항균력과 계면활성을 보였다.

• 대한화학회지
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• 제23권6호
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• pp.368-373
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• 1979

염화 N,N-이메틸 및 N,N-이에틸카르바모일의 가용매분해반응과 할라이드 교환$(Cl^-,\;Br^-,\;I^-)$반응, 및 염화 N,N-이페닐카르바모일의 가용매분해반응을 속도론적으로 연구하였다. 속도자료와 MO결과로부터 (1) 이 알킬화합물들은$S_N2$ 메카니즘으로, 이페닐화합물은 $S_N1$ 메카니즘으로 반응함을 알았고, (2) 염화이온교환에서는 결합절단이 중요한 반면, $Br^-$ 및 $I^-$ 교환반응에서는 결합 형성이 중요함을 알 수 있었다.

• 폴리머
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• 제31권5호
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• pp.417-421
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• 2007

덴드리틱 벤질 알코올을 트리에틸아민과 메탄술포닐클로라이드와 반응시켜서, 덴드리틱 벤질 클로라이드의 효율적인 합성이 이루어졌다. 이 반응은 히드록시기의 메실화 반응과 염소화 반응의 2단계 반응으로 이루어지는데, 중간체의 분리없이 한 반응 용기내에서 반응이 진행되는 경제적인 방법이다.

• 대한화학회지
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• 제20권5호
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• pp.358-363
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• 1976

물-에탄올 혼합용매속에서 1-염화 및 2-염화나프탈렌술포닐의 두 나프틸 화합물의 가용매 분해반응을 전기 전도도법을 사용하여 속도론적으로 연구하였다. 연구결과 2-나프틸 화합물의 반응속도상수가 1-나프틸 화합물의 것보다 컸다. 이것은 MO이론의 예측과는 반대였으며 전이상태에서 1-나프틸 화합물의 peri-hydrogen 효과에 기인된 것으로 설명할 수 있었다. Winstein 그림표의 m값과 Kivinen 그림표의 n값에 의하면 물-에탄올 혼합용매속에서의 두 염화 나프탈렌술포닐의 가용매 분해 치환반응은 $S_N2$형 반응과정으로 진행된다고 결론지웠다.

• 대한화학회지
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• 제20권5호
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• pp.406-416
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• 1976

Pyridine관여 탈수소 효소는 $N^1$-alkylnicotinamide chloride 유도체에 의하여 저해 작용을 받고 있는 바 저해제이 농도 변화에 따른 효소 저해작용이 가역 또는 비가역 불활성화 반응에 기인하는지의 여부를 밝혀 보기 위하여 토끼 근육으로 부터 유리한 L-${\alpha}$-glycerophosphate dehydrogenase를 사용하여 연구하였다. 이 효소의 저해작용은 상용한 저해제 유도체의 농도가 희박했을 경우 가역적인 효소저해 반응을 보여주고 있으나 저해제의 농도가 증가함에 따라 점차 비가역적인 효소 불활성화로서 나타남을 알았으며 이러한 비가역 불활성화 반응은 저해제의 농도가 증가함에 따라 형성될 수 있는 micelle 구조의 미세분자와의 결합에 의한 효소의 변성에 기인할 것이라고 결론을 얻었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.537-540
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• 2006

Over the past few decades, a considerable number of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in modeling of ionic flows. However, the majority of these researches have not dealt with the chloride binding isotherm based on the mechanism, although chloride binding capacity can significantly impact on the total service life of concrete under marine environment. The purpose of this study is to develop the model of chloride binding isotherm based on the individual mechanism. It is well known that chlorides ions in concrete can be present; free chlorides dissolved in the pore solution, chemical bound chlorides reacted with the hydration compounds of cement, and physical bound attracted to the surface of C-S-H grains. First, sub-model for water soluble chloride content is suggested as a function of pore solution and degree of saturation. Second, chemical model is suggested separately to estimate the response of binding capacity due to C-S-H and Friedel's salt. Finally, physical bound chloride content is estimated to consider a surface area of C-S-H nano-grains and the distance limited by the Van der Waals force. The new model of chloride binding isotherm suggested in this study is based on their intrinsic binding mechanisms and hydration reaction of concrete. Accordingly, it is possible to characterize chloride binding isotherm at the arbitrary stage of hydration time and arbitrary location from the surface of concrete. Comparative study with experimental data of published literature is accomplished to validity this model.