• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.865-870
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• 2014

Gold nanoparticles (AuNPs) were synthesized by laser (Nd:YAG, ${\lambda}$ = 1064 nm) ablation of a gold target immersed in various aqueous electrolyte solutions (7 mM of LiCl, NaCl, KCl, NaBr, and NaI) as well as in deionized water. The surface plasmon absorption and EDX of AuNPs so produced as well as their TEM images were analyzed to investigate the effects of ambient ions on the growth and aggregation of NPs. The size of AuNPs was reduced by laser ablation in the presence of chloride and bromide ions while it increased drastically when AuNPs were formed in iodide solution. Interestingly, triangular nanoplates were synthesized only in iodide solution. Surface chemistry on AuNPs in various electrolyte solutions was explored to elucidate the role of ions on the size and stability of AuNPs.

• 보존과학연구
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• 통권17호
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• pp.1-19
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• 1996

Desalting methods for chloride ions from the excavated iron objects were studied. These methods were compared with room temperature and heating condition of treating solution. During the Desalting treatments the $Cl^-$concentration of the solution were measured regularly and the plotted for $Cl^-$concentrations the square root of time, heating methods showed that the $Cl^-$ ions are more extracted. For the desalting treatments these plots were found to be flattening line, it was showed the changing second solution. Also, the changing solution in the room temperation detected less $Cl^-$ ions of heating treatment solution. As the examination for the relative humidity has compared for desalting objects during 8 days, it was showed a re-corroded appearance of R.H90%. As it did not detected a $Cl^-$ ions of re-corroded section, these phenomena were showed the naturally occuring corrosion of the objects in the high relative humidity.

• Computers and Concrete
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• 제10권5호
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• pp.523-539
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• 2012

Silica fume has long been used as a mineral admixture to improve the durability and produce high strength and high performance concrete. And in marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. In this paper, we proposed a numerical procedure to predict the chloride diffusion in a hydrating silica fume blended concrete. This numerical procedure includes two parts: a hydration model and a chloride diffusion model. The hydration model starts with mix proportions of silica fume blended concrete and considers Portland cement hydration and silica fume reaction respectively. By using the hydration model, the evolution of properties of silica fume blended concrete is predicted as a function of curing age and these properties are adopted as input parameters for the chloride penetration model. Furthermore, based on the modeling of physicochemical processes of diffusion of chloride ion into concrete, the chloride distribution in silica fume blended concrete is evaluated. The prediction results agree well with experiment results of chloride ion concentrations in the hydrating concrete incorporating silica fume.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.147-148
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• 2018

In order to compare the electrochemical performance with that of Calomel Electrode, MnO2 solid-state-electrode was fabricated and its potential and impedance were measured in chloride aqueous solution. As a result, the SCPS without chloride ions showed a potential of -200 mV or more and an impedance over 2000 Ωcm, but the potential below -600 mV and the impedance below -200 Ωcm showed as the chloride concentration in the solution increased. It is considered electrochemical studies on the corrosion of rebar are necessary for the MOE, which shows the same tendency as SCE and exhibits electrochemical performance, over the Mortar level in the future.

• Computers and Concrete
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• 제34권1호
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• pp.49-61
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• 2024

The present study concerns a removal of chloride ions and structural behaviour of concrete beam at electrochemical chloride extraction (ECE). The electrochemical properties included 1000 mA/m2 current density for 2, 4 and 8 weeks. It was found that an increase in the duration of ECE resulted in an increase in the extraction rate of chlorides, in the range of 35-85%, irrespective of chloride contamination. In structural behaviour, the strength and maximum bending moment of specimen was always lowered by ECE. Moreover, the flexural rigidity and bending stiffness were reduced by the loss of effective cross-section area in the linear elastic range. Simultaneously, the inertia moment was substantially subjected to 70% loss of the cross-section by the tensile strain at the condition of the failure. However, a lower rate of the inertia moment reduction was achieved by ECE, implying the higher resistance to the cracking, but the higher risk of deformation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.108-109
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• 2014

The purpose of this study is to enhance durability of solidifying mat. solidifying mat excellent mechanical properties of geotextile. multi-layer coating system is applied to the mat and the chloride ions penetration resistance, chemical resistance, accelerated carbonation test were evaluated by testing the durability. Durability test results are as follows. chloride ions penetration resistance results are coated mat is approximately 70 % lower than plain. chemical resistance test results are coated mat no discoloration. accelerated carbonation test results are coated mat is approximately 90 % lower than the plain.

• 한국대기환경학회지
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• 제10권2호
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• pp.124-129
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• 1994

Aerosol size distribution was determined using Anderson sampler for the anions( sulfate nitrate and chloride ) and TSP. Ionic species concentration and size distribution have been investigated in the daytime and nightime individually. Size classified samples were extracted with distilled water and analyzed for C $l^{[-10]}$ , N $O_3$$^{[-10]}$ and S $O_4$$^{2-}$, by ion chromatography. The size distribution of these ions and TSP was analyzed to investigate the seasonal and diurnal variation of concentrations as follows: (1)Size distribution of TSP showed bi- modal type in the daytime, but indicated tri-mode distribution in the nightime without any seasonal variation. (2)Sulfate concentrations were higher in fine- mode both in the daytime and nightime but fraction of sulfate was higher in coarse-mode during the Yellow Sand Period. (3)Nitrate and Chloride ions are dominant in fine-mode in winter while dominant in coarse-mode in the summer.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.43-44
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• 2022

In this study, the optimum amount of chloride ions is used to collaborate with hybrid corrosion inhibitor for carbon steel rebar treatment in simulated pore concrete (SCP) solution is discovered. The corrosion inhibition performance of hybrid inhibitors is carried on by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP). The highest corrosion inhibition resistance is found in case of LP-C2 after 240 h exposure. Surface studies including scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to figure out the surface morphology of the steel rebar treated with hybrid inhibitors in order to collaborate well with electrochemical studies. Anodic type inhibition action was confirmed by potentiodynamic polarization study.

• 한국물환경학회지
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• 제25권1호
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• pp.151-158
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• 2009

The objective of this study was to determine on optimum ratio of oxidant and catalyst and to evaluate affecting factors such as anions and cations on persulfate oxidation of organic pollutant. Fe(II) activated the persulfate anion to produce a sulfate free radicals and thus effectively used to degrade the target organic pollutant in aqueous system. The chloride ions reacted with sulfate radical produced the $Cl^{\cdot}$ atom and had positive effects on the oxidation of organic pollutant at the initial stage. However, it was observed that chloride ions had the scavenging effects on the rate of oxidation of organic pollutant. Cations and some heavy metals were partly able to activate the persulfate anion to generate a sulfate free radical. However, high levels of cations inhibited the oxidation of organic pollutant.

• 한국구조물진단유지관리공학회 논문집
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• 제18권4호
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• pp.84-91
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• 2014

본 연구에서는 콘크리트 구조물의 강도 향상을 위하여 혼입하고 있는 메타카올린의 내구성능 향상 효과를 규명하기 위하여 염화물이온 확산계수 및 단열온도상승량을 측정하였다. 그 결과, 메타카올린의 혼입으로 인하여 염화물이온 확산계수가 작아짐이 확인되었으며 플라이 애쉬의 첨가를 통하여 유동성의 저하를 억제할 수 있었다. 따라서 염분침투저항성을 확보하면서 물결합재비를 크게 하는 것이 가능하므로 메타카올린의 혼입으로 발생되는 단열온도상승량을 억제할 수 있어 콘크리트의 내구성능이 향상될 수 있음을 확인하였다.