• Journal of the Korea Concrete Institute
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• 제21권4호
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• pp.409-417
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• 2009

In this study, autogenous crack healing and artificial crack healing using electrochemical electro deposition method were conducted to compare in the aspects of corrosion monitoring. Furthermore, the analysis of impressed voltage characteristics, galvanic current and linear polarization resistance comparison, and photo image processing technique were performed for quantitative comparisons of healing ratio. As a result, it was found that, in view of impressed voltage of artificial crack healing, the measured voltage was increased as time goes by. From the galvanic test results of artificial crack healing, the current vs. potential distribution value were formed widely in comparison with autogenous crack healing. In this point, it was shown that artificial crack healing has more eleatic resistance capacity than autogenous crack healing technique. Finally, it was found that artificial crack healing was 1.63 times higher than autogenous healing in view of crack healing ratio.

• Journal of the Korean Chemical Society
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• 제54권4호
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• pp.374-379
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• 2010

The interaction of dichlorophenol isomers with the micellar system of TTAB (tetradecyltrimethylammonium bromide) was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of dichlorophenol isomers into the micellar system have been measured with the change of temperature and the various thermodynamic parameters have been calculated and analyzed from these changes. The results show that the values of ${\Delta}G^{\circ}_s$ and ${\Delta}H^{\circ}_s$ are all negative within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of dichlorophenol isomers have been also measured. There was a great change on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate the solubilization sites of each isomers in the micellar system of TTAB.

• Journal of the Korean Chemical Society
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• 제42권4호
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• pp.383-390
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• 1998

The interaction of phenoxide anion with several cationic surfactant micelles (DTAB, TTAB, CTAB, CDEAB, and CTAC) was studied by UV/Vis spectrophotometric method. The solubilization constants of phenoxide anion into the cationic micellar phase and the critical micelle concentration of these surfactants in the presence of the phenoxide anion could be determined from the absorbance changes. The measured solubilization constants were changed according to the following order: $K_s(CTAC)>K_s(CDEAB)>K_s(CTAB)>K_s(TTAB)>K_s(DTAB).$ Effects of salts(NaCl and NaBr) and n-alcohols(butanol, pentanol, and hexanol) on the solubilization of phenoxide anion by the TTAB system have been also measured and analyzed. There was a great decrease of solubilization constant and CMC with these additives. The standard Gibbs free energy, enthalpy, and entropy changes for the solubilization of phenoxide anion by the TTAB system were calculated from the temperature dependence of $K_s$ values.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.2005-2009
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• 2008

하천수변조사는 하천수변의 물리 화학 생물학적 특성 파악과 이들의 상호 연관성 및 변화양상을 분석하기 위한 기초자료 수집과정이다. 하천수변조사는 치수 및 이수기능뿐아니라 하천환경 기능을 보전, 재생 및 복원시키고자 하는 하천정비사업에 이용되고 있으며, 이에 따라 하천정비기본계획, 하천환경정비사업 등에서 많은 조사가 이루어지고 있다. 그러나 수집된 자료의 형태가 대부분 도면이나 이미지 형태로 관리되고 있어 향후에 수변의 변화 상태를 갱신하기가 어려운 실정이다. 본 연구에서는 행정중심복합도시 권역내의 국가하천, 지방하천, 소하천을 대상으로 하천수변조사를 실시하였으며 조사결과의 체계적 관리를 도모하기 위하여 하천수변조사지도 DB 구축과 이를 관리할 수 있는 시스템을 개발하였다. 본 연구의 성과는 단기적으로는 하천환경정비시 보전 및 복원 방향의 설정, 하천의 현재 상황을 파악하고 이를 공사 진행에 반영, 공사 과정 중에서 하천의 반응상태를 파악하여 사업진행이나 방식을 개선하는데 활용될 수 있다. 장기적으로는 행정중심복합도시 조성 전후의 하천환경 및 생태변화상을 제공할 수 있고 자연친화적인 하천환경 관리를 위한 하천환경정보를 제공할 수 있다.

• Journal of the Korean Chemical Society
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• 제57권2호
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• pp.279-288
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• 2013

In this study, we analyzed the values of ionization and ionization constants in the chemistry textbooks developed during 1945-2009 year. The chemistry teachers compared strength of strong acids in aqueous solution by questionnaire. In the questionnaire, we searched chemistry teachers' cognitions about the discordance reason of ionization constant formulation and the values in the textbooks. The subjects were 46 chemistry teachers. As results, the teachers compared the strength of strong acids in aqueous solution based on the ionization and ionization constant values in the textbooks. They didn't notice the problem of discordance of ionization constant formulation and the values in the textbooks. Even though they recognized the problem, they could not find the solution, and thought the problem arrived by experiment error or measurement error.

• Journal of the Korean Institute of Gas
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• 제22권6호
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• pp.1-7
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• 2018

Currently chemical plant risk have been issued by occurring frequent accidents. Accidents can be generally composed of fire, explosion, release in chemical plant. In case of fire and explosion, accident victims are occurred immediately after accident but release accident, late emergency response cause damage to worker. Especially, there are many victims by late emergency response against chemical exposure to skin. In case of chemical exposure to skin, irreversible damage like death, blindness, burn can be prevented by washing immediately. Safety shower can provide the cleaning for chemical exposure to eye, skin. Most of chemical plants are built in 1980s so equipment become superannuated. In this reason, safety shower also cannot operate normally in emergency situation. Therefor safety shower should be managed by installation and management guideline. This study perform the establishment guideline for safety shower installation and inspection to increase the reliability.

• Korean Journal of Plant Resources
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• 제36권1호
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• pp.100-106
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• 2023

In order to control the fire blight disease, all plants within the radius of the diseased orchard were removed in the early stage of the outbreak, or antibiotics control was performed for prevention. Since the beginning of antibiotics use on plants, the potential for development of resistance to antibiotics by the plant pathogen and unintended detrimental effects on the fruit trees and environment has become a problem. The purpose of this study is to determine the degree of phytotoxicity to fruit trees caused by excessive spraying of the fire blight disease disinfectant and to establish basic data for safe disinfectant guide. We analyzed whether damage to the fruit tree and the maximum residual limit of fruit was exceeded when three kinds of the fire blight disease disinfectants were continuously sprayed in excess of the number of safe use during the growing season. There was no phytotoxicity in apple 'Fuji' and pear 'Niitaka', and oxolinic acid was detected beyond the limit of quantitation in 'Fuji' grown without a bag, and the other disinfectants were detected below the maximum residue limit. When these disinfectants are continuously sprayed in excess of the number of safe, phytotoxicity may remain on the fruit. Therefore, it is necessary to observe the prescribed dilution factor and observe the safe frequency and the timing of use.

• Journal of the Korean Institute of Gas
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• 제3권1호
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• pp.21-26
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• 1999

Chemical plant's fire and explosion does not only damage to the chemical plants themselves but also damage to people in or near of the accident spot and the neighborhood of chemical plant. For that reason, Chemical process safety management has become important. One of safety management methods is called 'the quantitative analysis', which is used to reduce and prevent the accident. The results of the quantitative analysis could be used to arrange the equipments, evaluate the minimum safety distance, prepare the safety equipments. In this study we make the computer program to make easy to do Quantitative analysis of the accident. The output of the computer program is the magnitude of fire(pool fire and fireball) and explosion(UVCE and BLEVE) effects. We used the thermal radiation as a measure of fire magnitude and used the overpressure as a measure of explosion magnitude. In case of BLEVE, the fly distance of fragment can be evaluated. Also probit analysis was done in every case. As the case study, Buchun LPG explosion accident in Korea was analysed by the program developed. The simulation results showed that the permissible distance was 800m and probit analysis showed that 1st degree bum, 2nd degree burn, and death distances are 450, 280, 260m, respectively the simulation results showed the good agreement with the results from SAFER PROGRAM made by Dupont.

• Journal of Trauma and Injury
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• 제19권2호
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• pp.173-177
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• 2006

Hydrofluoric acid is a colorless gas or fuming liquid with a strong, irritating odor. Hydrofluoric acid burns are uncommon; however, if severe burn occur, they caused death from systemic effects, such as fatal cardiac arrthmia. We experienced two cases of hydrofluoric acid chemical burns on digits. These patients had typical clinical features of hydrofluoric acid chemical burns, such as pulsating pain at the burn site, as well as ischemic and necrotic skin changes. The hydrofluoric acid chemical burn was confirmed by a history of exposure. Subsequently, we made a calcium gluconate gel by mixing 20% calcium gluconate, an antagonist against hydrofluoric acid, with lubricant, and we injected 10% calcium gluconate subcutaneously when they complained of pain rated at higher than 5 on the pain scale. Simultaneously, we monitored the patients' electrocardiographs and checked their serum total calcium, ionized calcium, and magnesium levels serially. Clinical presentations and the emergency management of hydrofluoric acid chemical burns were reviewed along with the current literature. These patients were discharged without any significant complications.

• Journal of the Korean Chemical Society
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• 제31권5호
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• pp.452-456
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• 1987

Acidic strength of benzenesulfonic acid (HBs) and it's derivatives, p-toluenesulfonic acid(HTs), p-chlorobenzenesulfonic acid(HCs) and m-nitrobenzenesulfonic acid(HNs), were measured in the anhydrous acetic acid medium by spectrophotometry. p-naphtholbenzein (PNB) was used as an indicator base and the ionization constants of HTs, HBs, HCs and HNs were $3.5{\times}10^2,\;4.1{\times}10^2,\;19.3{\times}10^2\;and\;50{\times}10^2$, respectively, at 20.0${\pm}$0.1$^{\circ}$C.