• Computers and Concrete
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• v.17 no.1
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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.

• Journal of Biomedical Engineering Research
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• v.8 no.2
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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.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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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.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.286-290
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• 2006

New quaternary ammonium chlorides, [alkyldimethyl-[5-(2-phenylthiazol-4-yl]-1,3,4-oxadizol-2-ylmethyl]quaternary ammonium chlorides (ADOQACs): 6] were obtained with high yields by the reaction of compound 5 with N,N-dimethylalkyl amines in isopropyl alcohol. The structures and physical properties of the synthesized compounds were investigated and those surface-active properties were measured. The surface tension ($\gamma_{cmc}$) and the minimal inhibitory concentration (MIC) of compound 6 were found to be influenced by the number of alkyl chain carbon. Especially, compounds 6c and 6d exhibited high anti-bacterial activities and good surface-active properties.

• Journal of the Korean Chemical Society
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• v.23 no.6
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• pp.368-373
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• 1979

Kinetic studies have been carried out on solvolyses and halide exchanges $(Cl^-,\;Br^-,\;I^-)$ of N,N-dimethyl-, N,N-diethylcarbamoyl chlorides, and solvolyses of N,N-diphenylcarbamoyl chloride. Kinetic results together with simple MO analysis indicated that: (a) N,N-dialkylcarbamoyl chlorides reacted via the $S_N2$ mechanism, while N,N-diphenylcarbamoylchloride reacted via the $S_N1$ mechanism; (b) in chloride exchanges, the bond-breaking appeared to be important, whereas in bromide and iodide exchanges, the bond-formation was shown to be important.

• Polymer(Korea)
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• v.31 no.5
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• pp.417-421
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• 2007

A successful rapid synthesis of dendritic benzyl chlorides from dendritic benzyl alcohols using methanesulfonyl chloride/$Et_3N$ as activating agents was described. In this method, each dendritic benzyl chloride can be prepared in one pot: no isolation of intermediate mesylated dendrons is required. The key steps in the syntheses of dendritic benzyl chlorides were the mesylation of the hydroxymethyl group followed by the chlorination by in-situ generated triethylammonium chloride.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.358-363
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• 1976

Kinetic studies on solvolytic reactions of 1-and 2-naphthalene sulfonyl chlorides in ethanol-water mixtures have been carried out by means of conductometry at several temperatures. The rate constant for 2-naphthyl compound was larger than that for 1-naphthyl compound. This was contrary to the prediction of MO theory and could be rationalized as due to the peri-hydrogen effect in the transition state for 1-naphthyl compound. Based on m values of Winstein plots and n values of Kivinen pacolots it was concluded that the solvolytic displacement of the two naphthalene sulfonyl chlorides in ethanol-water mixtures proceed via $S_N2$ process.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.406-416
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• 1976

A series of $N^1$-alkylnicotinamide chlorides, $N^1$-methyl-to $N^1$-dodecylnicotinamides inclusive were studied with rabbit muscle L-${\alpha}$-glycerophosphate dehydrogenase to investigate the possibility of reversible and irreversible inactivation of the pyridine-linked dehydrogenases by the coenzyme-competitive inhibitor derivatives. The inhibition of the enzyme by $N^1$-alkylnicotinamide chlorides was demonstrated to be reversible at the dilute concentration of the inhibitors but this reversible inhibition was found to be followed by an irreversible time-dependent inactivation measuable at high concentrations of the inhibitors. The properties of this time-dependent inactivation were discussed on the basis of the denaturation of the enzyme by the binding of small micelle-like structures formed at higher concentrations of the inhibitors.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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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.