• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.165.1-165
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• 2003

복숭아는 절단 후 표면의 갈변현상이나 당도 저하 등이 발생하여 신선편이 식품화시 품질열화의 원인이 된다. 이에 본 실험에서는 일차적으로 유명 품종에 한해 fresh-cut peach의 anti-browning chemicals를 탐색하고, 그 결과를 통해 이차적으로 효과가 우수한 chemicals를 선정하여 백향 품종에 농도별 실험을 행하였다. 유명 품종을 반으로 절단한 후 제핵하고 8등분하여 1% ascorbic acid, 1% sodium chloride, 1% sodium ascorbate monohydrate, 0.005% 4-hexylresorcinol 용액에 3분간 침지시켜 draining한 후, PP tray에 담고 PP film으로 밀봉하여 4$^{\circ}C$에서 저장하였다. 가용성고형분은 to sodium chloride 용액으로 처리한 구에서 가장 높게 유지되었고 pH 또한 비교적 일정하였으며, 1% sodium chloride과 1% sodium ascorbate monohydrate 용액으로 처리한 구의 L값이 높게 유지되었다. 따라서 fresh-cut peach에 효과가 있는 것으로 판단되는 이 두 chemicals의 농도별 용액을 조제하여 같은 방법으로 백향 품종의 갈변저해제로서 처리하였다. 그 결과 2% sodium chloride의 가용성고형분이 가장 높게 유지되었으며 2% sodium ascorbate monohydrate 다음으로 2% sodium chloride 용액 처리구의 L값의 변화 양상이 가장 양호한 것으로 나타났다. 따라서 종합적으로 살펴볼 때, 2% sodium chloride 용액의 처리가 fresh-cut peach의 품질 변화 억제에 적합하다고 판단되었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.181-184
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• 2005

When concrete structures are exposed under marine condition for a long time, the steel in concrete is corroded due to the ingression of chlorides in the seawater. Because the damages of corrosion resulting from the chloride ion are very serious, many researches have been performed. However evaluation on chloride attack of concrete structures are not fully examined, recently. Therefore, the objective of this paper is to study the applicability of colormetric method. For the purpose of this, reaction mechanism of colormetric method were investigated, and the colormetric method is applied for marine concrete structures. According to the test results, the diffusion coefficient by colormetric method is not so different to the value of chloride concentration profile test. It is confirmed that the colormetric method is useful tool for estimating the chloride of concrete structures in situ. The average chloride amount of colored parts indicates 0.9kg/$m^{3}$ per concrete unit weight.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.40-41
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• 2018

The purpose of this study is to compare the amount of critical chloride of rebar embedded in concrete according to the substitution rate of admixture. In order to determine the starting point of corrosion of rebar, electrodes were embedded in concrete, chloride was supplied, and OCP of rebar was observed in real time. The amount of the contaminants in the concrete surrounding the rebar was judged to be the critical corrosion chloride contents of the rebar at the start of the corrosion. As a result of the comparative evaluation, it was confirmed that the critical chloride contents of the rebar decreased with increasing the substitution ratio of the admixture.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.87-91
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• 2009

Recycling demolished concrete as an alternative source of coarse aggregates for the production of new concrete can help solve the growing waste disposal crisis and the problem of depleted natural aggregates. The purpose of this study is to investigate chloride migration of recycled aggregate concrete containing pozzolanic materials by chloride migration coefficient. The specimens were made with recycled coarse aggregate as various replacement ratio(10, 30, 50%) and metakaolin, blast furnace slag, fly ash is replaced for recycled concrete with mixing ratio 20%. The major results are as follows. 1) Compressive strength of recycled aggregate concrete containing pozzolanic materials increase as curing age and chloride migration decrease. 2) When the replacement ratio of recycled coarse aggregate is 30%, the chloride migration coefficient of recycled concrete containing blast furnace slag, metakaolin shows the similar or lower value than plain concrete at all ages.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.725-728
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• 2006

This research investigates the characteristics of chloride fixation in non-sintering cement(NSC) matrix. NSC was manufactured by adding phosphogypsum and slack lime to granulated blast furnace slag as sulfate and alkali activators. As a result, the concentration of chloride ion in pore solution of NSC-solidified matrix is more low than that of OPC-solidified matrix containing the same chloride content in cement paste. Also, the concentration of chloride ion in pore solution of NSC-solidified matrix is similar with that of BSC-solidified matrix containing the same chloride content in cement paste.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.553-556
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• 2006

Chloride penetration is the main reason which causes the deterioration of concrete structures. Chloride penetration of concrete structures due to chemical-physical phenomena can be profitably analyzed by means of model-based simulations. The main purpose of this paper is to analyze chloride penetration considering self-desiccation, convection and admixture(GBFS: granulated blast-furnace slag) effects. Basic governing equations are modified properly to apply these effects to chloride penetration analysis. Temperature and relative humidity data of In-Cheon from Korea Meteorological Administration are used for analyzing chloride penetration.

• Proceedings of the KAIS Fall Conference
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• 2000.10a
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• pp.245-250
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• 2000

고습도 또는 결로시 내수성을 지니는 저항형 습도센서를 제조하기 위하여 vinylbenzyl tributyl phosphonium chloride를 포함하는 4원 공중합체를 합성하여 저습도와 고습도 범위에서 측정이 가능한 습도센서용 감습막을 제작하였다. 1,5-dibrompentane과 4차 염화 가교 반응을 통하여 최종 저항형 습도센서를 제작하였다. 감습막은 알루미나 기판에 한 쌍의 금 paste가 인쇄된 전극을 사용하였으며, 감습막은 다양한 비율의 vinylbenzyl tributyl phosphonium chloride, 2-(dimethlamino)ethyl methacrylate, 2-ethylhexyl acrylate, 그리고 [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride 등을 이용하여 제조하였다. 감습막은 micro-syringe를 이용하여 도포하였으며 건조 oven에서 50℃에서 6시간 동안 가교반응을 진행하였다. 습도센서의 임피던스 특성은 2-(dimethylamino)ethyl methacrylate 또는 [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride의 함량이 증가할수록 감소하였다. vinylbenzyl tributyl phosphonium chloride / 2-(dimethylamino)ethyl methacrylate / 2-ethylhexyl acrylate / [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride의 조성비가 4/4/1/1인 공중합체의 경우 30-90%RH 범위에서 2.64 ㏁ - 3.11 ㏀의 임피던스 특성을 보였으며 우수한 직선성과 낮은 히스테리시스 나타내었다.

• Bulletin of the Korean Chemical Society
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• v.11 no.1
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• pp.65-69
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• 1990

The nucleophilic substitution reactions of naphthalene-1,5-disulfonyl chloride and 4-fluorosulfonylbenzenesulfonyl chloride with p-substituted anilines and methyl substituted pyridines in methanol-acetonitrile mixtures and hydrolyses of those disulfonyl halides have been studied by means of conductometric and polarographic methods. A large difference in the selective parameter, ${\rho}_N$ between mono-sulfonyl chloride and disulfonyl halide can be taken as an evidence that the second $SO_2Cl$ grolup of naphthalene-1,5-disulfonyl chloride also takes part in the reaction in contrast to sulfonyl fluoride in 4-fluorosulfonylbenzenesulfonyl chloride, which only acts as a substituent in the nucleophilic substitution reaction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.166-167
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• 2019

In this study, to test the performance of concrete used as a concrete admixture as a recycling method of CGS, gypsum was mixed and the chloride ion penetration resistance test of CGS and BFS substituted concrete was conducted. As a result, it was found that without gypsum type test specimen, the CGS sustituted test specimens had lower chloride ion penetration resistance than the BFS substituted specimens. When gypsum was added, it was confirmed that the chloride ion penetration resistance was poor regardless of the type of admixture. In addition, it was confirmed that both admixtures were less resistant to chloride ion penetration than OPC, regardless of the presence of gypsum. However, considering the uneven quality variation of coal, which greatly affects the quality of CGS, further research is needed.

• Computers and Concrete
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• v.10 no.3
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• pp.219-229
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• 2012

Carbonation is a widespread degradation of concrete and may be coupled with more severe degradations. An experimental investigation was carried out to study the effect of carbonation on chloride ion diffusion of concrete. The characteristic of concrete after carbonation was measured, such as carbonation depth, strength and pore structure. Results indicated that carbonation depth has a good linear relation with square root of carbonate time, and carbonation can improve compressive strength, but lower flexural strength. Results about pore structure of concrete before and after carbonation have shown that carbonation could cause a redistribution of the pore sizes and increase the proportion of small pores. It also can decrease porosities, most probable pore size and average pore diameters. Chloride ion diffusion of concrete after carbonation was studied through natural diffusion method and steady state migration testing method respectively. It is supposed that the chloride ion concentration of carbonation region is higher than that of the sound region because of the separation of fixed salts, and chloride ion diffusion coefficient was increased due to carbonation action evidently.