• 한국식품영양과학회지
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• 제31권6호
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• pp.1163-1166
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• 2002

식중독 미생물 Salmonella typhimurium ATCC 14028, Staphylococcus aureus KCTC 2199, Vibrio parahaemolyticus ATCC 17802에 대한 은 이온의 항균력을 PAper Disk 방법과 액체 배양법에서 조사하였다. S. typhimurium와 V. parahaemolyticus의 경우 각각 2,10ppm의 은 이온 농도에서 생육저해환이 발견되었으며 농도가 증가함에 따라 생육 저해의 정도가 증가하였다. 그러나 S.aureus는 20 ppm의 은 이온 농도에서도 생육 저해환이 관찰되지 않았다. 액체 배양에서 은 이온의 항균 능력은 S. typhimurium, V.parahaemolyticus, S.aureus에 대해서 각각 03 ppm, 0.5 ppm, 5 ppm 이상에서 관찰되었고, 은 이온의 농도가 증가함에 따라 생육 저해는 크게 나타났다.

• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.381-390
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• 2023

본 연구에서는 염해를 받은 콘크리트의 역학적 성능 평가를 수행하고, 실험 결과를 바탕으로 염소이온 농도에 따른 압축응력변형률 모델을 제시하였다. 염해를 모사하기 위해 콘크리트 배합 시 CaCl₂ 용액을 첨가하였으며, 염소이온의 농도는 결합재의 중량 대비 0, 1, 2, 4 %가 되도록 하였다. 콘크리트의 최대 압축응력 이후의 응력-변형률 곡선을 조사하기 위해 변위 제어를 통해 압축강도를 측정하였다. 염소이온 농도가 1 %인 경우에는 최대 압축응력이 증가하였으나, 염소이온 농도가 2 % 이상인 경우에는 최대 압축응력이 감소하였다. 최대 압축응력에서의 변형률의 경우 재령 7일의 시편에서는 염소이온 농도에 따른 경향이 나타나지 않았다. 재령 28일의 시편에서는 염소이온 농도가 증가함에 따라 감소하였다. 재령 28일의 최대 압축응력와 변형률의 변화를 이용하여 Popovics model에 기반한 응력-변형률 곡선 모델을 제시하였다. 염소이온의 농도 증가에 따른 역학적 성능 저하의 원인을 조사하기 위해 수화생성물 분석을 수행하였다. 염소이온의 농도가 증가함에 따라 Friedel's salt가 증가하고, portlandite가 감소하는 것을 확인하였다.

• 한국물환경학회지
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• 제21권1호
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• pp.14-20
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• 2005

A feasibility study has been conducted regarding the application of waste coffee grounds as an adsorbent for the treatment of nickel ion containing wastewater. The major variables which considered to influence the adsorbability of nickel ion were its initial concentration, reaction temperature, pH, and coexisting ion. The specific surface area of coffee grounds used in the experiment was found to be ca. $39.67m^2/g$, which suggesting its potential applicability as an adsorbent due to its relatively high surface area. In the experimental conditions, more than 90% of the initial amount of nickel ion was shown to adsorb within 15 minutes and equilibrium in adsorption was attained after 3 hours. The adsorption behavior of nickel ion was well explained by Freundlich model and kinetics study showed that the adsorption reaction was second-order. Adsorption was reduced with temperature and its change of enthalpy in standard state was estimated to be -807.05 kJ/mol. Arrhenius equation was employed for the calculation of the activation energy of adsorption and nickel ion was observed to adsorb on coffee grounds exoentropically based on thermodynamic estimations. As pH rose, the adsorption of nickel ion was diminished presumably due to the formation of cuboidal complex with hydroxide ion and the coexistence of cadmium ion was found to decrease the amount of nickel ion adsorption, which was proportional to the concentration of cadmium ion.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.27-28
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• 2018

Deterioration of reinforced concrete structures due to salt corrosion is a phenomenon that can be easily seen, and the main reason for deterioration is chloride ion. Therefore, researches are actively conducted to control chlorine ion penetration worldwide. The purpose of this study is to evaluate the chloride ion fixation capacity of Portland cement paste containing Hydrotalcite. For this purpose, cement paste containing 0%, 2.5%, and 5% of Hydrotalcite was sealed and cured for 28 days, and the cured cement paste was crushed. Chloride ion solution was prepared at a concentration of 0.5M using NaCl, and the powdered cement paste was reacted for a specific time in aqueous chloride ion solution. After the reaction, the concentration of the chloride ion aqueous solution was measured using a silver nitrate potentiometric titrator, and the reacted cement paste was analyzed using XRD and FT-IR.

• Corrosion Science and Technology
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• 제13권4호
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• pp.145-151
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• 2014

The objectives of this study are to investigate the effect of the concentration ratios of Ni and Fe ions on crud deposition onto the fuel cladding surface in the simulated primary environments of a pressurized water reactor. Crud deposition tests were conducted in the Ni and Fe concentration ratios of 20:20 ppm, 39:1 ppm and 1:39 ppm at $325^{\circ}C$ for 14 days. In the case of the same Ni and Fe ion ratio (20:20), nickel ferrite with a polyhedral shape was formed. Nickel oxide deposits with a needle shape were formed in the condition of high Ni to Fe ion ratio (39:1), While polyhedral iron oxide and needle-like nickel oxide formed in the condition of low Ni to Fe ion ratio (1:39). The amount of deposits increased, when Fe oxides were formed. This indicates that Fe rich oxides stimulated Ni oxide deposition.

• Computers and Concrete
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• 제33권1호
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• pp.1-11
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• 2024

Aggressive environmental conditions, and especially the acidic effects of sulfate ion penetration, have reduced the lifetime of concrete structures in some areas, especially coastal and marine areas. In this research, at first, samples made of type II and V cement were kept in a solution of magnesium sulfate (MgSO₄) for a period of 90 and 180 days, the change of appearance. Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD), were used to analyze the microstructure and the complex mineral composition of the concrete after exposure to corrosive environments. Then solving the differential equation governing the sulfate ion penetration, which is based on the second Fick law, it has been tried to determine the concentration of sulfate ions inside the concrete. In the following, an attempt has been made to improve the prediction of sulfate ion concentration in concrete by using Crank's penetration equation. At the same time, the coefficient in the Crank's solution have been optimized by using the Particle Swarm Optimization (PSO algorithm). The comparison between the results shows that the values obtained from Crank's relation are closer to the experimental results than the equation obtained from Fick's second law and shows a more accurate prediction.

• 대한화학회지
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• 제32권5호
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• pp.483-494
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• 1988

이온쌍크로마토그래피에서 방향족 유기산들의 머무름을 연구하기 위하여 Amberlite XAD-4 수지에 대한 분배계수 값을 측정하였다. 유기산들의 XAD-4 수지에 대한 흡착은 시료의 농도, 용액의 pH 그리고 이온쌍 형성시약의 농도에 따라 영향을 받는다. Tetraalkylammonium염과 같은 이온쌍 형성 시약에 의한 유기산의 XAD-4 수지에 대한 흡착 증가는 전기적 이중층에 의한 이온 상호작용에 기인됨을 알았으며, 유기산과 이온쌍 형성 시약과의 상호작용은 공존이온과 상대이온의 종류와 농도에 따라 영향을 받음을 알았다. 한편, 이온쌍 형성시약과 메탄올의 농도 변화에 따른 XAD-4수지에 대한 유기산의 뱃치법과 용리법에서 얻은 용량인자의 관계는 좋은 직선관계를 보여주었다. 따라서 뱃치법의 실험으로써 용리법의 머무름을 예측할 수 있는 가능성을 제시하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.133-136
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• 2000

Soil decontamination process was conducted to study adsorption and modeling characteristic of Sr$^{2+}$ ion using citric acid and water system with TRIGA soil. When the concentration of citric acid was increased, the BTC of Sr$^{2+}$ ion was to be closed to the BTC of $^3$$H_2O$ at experiments of soil adsorption. Beside, when the concentration of citric acid was under 0.01M Sr$^{2+}$ ion, BTLs was asymmetry. It was characteristic of nonequilibrium adsorption. R and $K_{p}$ , were decreased to be increased the concentration of citric acid. Asymmetry modeling was nearly the same to be compare with symmetry modeling in decontamination process, when the concentration of citric acid was decreased. Result of experiment was agree with asymmetry and symmetry model, when the concentration of citric acid was increased.eased.

• Mass Spectrometry Letters
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• 제12권1호
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• pp.26-30
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• 2021

The impurity concentration is a crucial parameter for semiconductor thin films. Evaluating the impurity distribution in silicon thin film is another challenge. In this study, we have investigated the doping concentration of boron in silicon thin film using time of flight secondary ion mass spectrometry in dynamic mode of operation. Boron doped silicon film was grown on i) p-type silicon wafer and ii) borosilicate glass using hot wire chemical vapor deposition technique for possible applications in optoelectronic devices. Using well-tuned SIMS measurement recipe, we have detected the boron counts 101~104 along with the silicon matrix element. The secondary ion beam sputtering area, sputtering duration and mass analyser analysing duration were used as key variables for the tuning of the recipe. The quantitative analysis of counts to concentration conversion was done following standard relative sensitivity factor. The concentration of boron in silicon was determined 1017~1021 atoms/㎤. The technique will be useful for evaluating distributions of various dopants (arsenic, phosphorous, bismuth etc.) in silicon thin film efficiently.

• 상하수도학회지
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• 제9권3호
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• pp.88-98
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• 1995

Several kinds of coagulants such as aluminum sulfate, PAC, PASS are being used to treat drinking water resulting in residual aluminum ions in the water. Recently, it has been reported that high intake of aluminum ion may cause neurological dieseases such as Alzheimer's diesease and presenile dementia. Because of the possible adverse effect, WHO and EEC recommand to regulate residual aluminum. The autorities in Korea also has plan of regulating residual alunimum from 1995. But there is not enough information about the range of residual aluminum ion concentration when the aluminum sulfate, PAC or PASS has been used as a coagulant. Therefore the study has been conducted to find out the range of residual aluminum ion concentration after using aluminum sulfate, PAC, and PASS. Furthermore the effect of turbidity and alkalinity have been investigated. The experimental results are summarized as; 1. Most of the residual aluminum ion concentrations were within $10^{-6}$ and $10^{-5}mole/l$. Three coagulants have not showed any considerable difference in the residual aluminum concentration up to 50 NTU. However PAC has showed the least residual aluminum in high turbidity water over 100 NTU. 2. The low alkalinity water having 25mg/l as $CaCO_3$ has showed less residual aluminum than the water having 50mg/l alkalinity. However, the difference was not significcant. 3. Even the lowest residual aluminum concentration was over 0.05mg/l. Therefore the process to reduce residual aluminum would be necessary in water treatment plants.