• Computers and Concrete
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• 제7권5호
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• pp.421-435
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• 2010

This paper utilizes the modified Davis model and the mode coupling theory, as parts of the electrolyte solution theory, to investigate the diffusivity of the ion in concrete. Firstly, a computational model of the ion diffusion coefficient, which is associated with ion species, pore solution concentration, concrete mix parameters including water-cement ratio and cement volume fraction, and microstructure parameters such as the porosity and tortuosity, is proposed in the saturated concrete. Secondly, the experiments, on which the chloride diffusion coefficient is measured by the rapid chloride penetration test, have been carried out to investigate the validity of the proposed model. The results indicate that the chloride diffusion coefficient obtained by the proposed model is in agreement with the experimental result. Finally, numerical simulation has been completed to investigate the effects of the porosity, tortuosity, water-cement ratio, cement volume fraction and ion concentration in the pore solution on the ion diffusion coefficients. The results show that the ion diffusion coefficient in concrete increases with the porosity, water-cement ratio and cement volume fraction, while we see a decrease with the increasing of tortuosity. Meanwhile, the ion concentration produces more obvious effects on the diffusivity itself, but has almost no effects on the other ions.

• 한국염색가공학회지
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• 제3권3호
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• pp.15-22
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• 1991

The effects of electrolytes on color fastness properties of cotton fabric with Congo Red have been studied at $90^{\circ}C$. Each dyeing carried with $10 \times 10^{-6}M$ of Congo Red and with various concentration of electrolytes. The results obtained from this study were as follow 1. In the case of none, the fastness to washing became worse, but the fastness to light better with increasing dye concentration. 2. In the case of additing an electrolyte, the fastness to washing became worse and the fastness to light better than the case of none. The samples had become yellower after washing test. Yellowness had been reduced after fade-O-meter test. 3. What kind of electrolytes could not have any effect on the fastness to washing, but they influenced the fastness to light in the order of LiCl

• 한국임상수의학회지
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• 제22권1호
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• pp.70-73
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• 2005

A 9-year old female Shih Tzu dog was presented to the Veterinary Medical Teaching Hospital of Seoul National University with a history of chronic intermittent anorexia and vomiting of 4-year duration. She visited 3 years ago with the same clinical signs but has not been treated regularly due to waxing-waning course. On the physical examination, no specific findings were found. CBC, serum chemistry, radiography, ACTH stimulation test, evaluation of serum T4 and TSH concentration were performed. Hypoadrenocorticism was diagnosed with the ACTH stimulation test. And then, secondary hypoadrenocorticism was diagnosed with ACTH stimulation test, pre-ACTH aldosterone concentration, endogenous ACTH concentration. As electrolyte concentrations were normal, glucocorticoid (0.15 mg/kg bid PO) alone was administered. She has recovered from the clinical signs and has been doing well. It is suggested that the differentiation of secondary hypoadrenocorticism from primary hypoadrenocorticism is important as the secondary hypoadrenocorticism occurs rarely and the symptoms are non-specific with normal electrolyte concentrations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1252-1254
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• 1997

Direct methanol fuel cell based on a proton-exchange membrane electrolyte was investigated. 60% Pt-Ru/C and 60%Pt/C catalysts were employed for methanol oxidation and oxygen reduction, respectively. Morphologies of the catalysts were investigated by x-ray power diffraction, energy dispersive x-ray spectroscopy, and transmission microscopy. Electrochemical characteristics of the catalysts were tested by using cyclic voltametry technique. I-V characteristics of the fuel cell were tested by changing methanol concentration, temperature, and Nafion type as a proton-exchange membrane electrolyte. AC impedance technique was used to investigate the electrochemical performance of the fuel cell. The performance of single cell was enhance with increasing cell temperature. High operation temperature attributed to the combined effects of the reduction of ohmic resistance and polarization. High cell voltage was obtained from the concentration of 205M methanol. With Nafion 112, a current density of $230mA/cm^2$ at 0.55V was obtained from the concentration of 2.5M methanol.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.357-361
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• 1999

GOD electrochemically immobilized in PPy/GOD complex have an effect on redox properties of the complex. In the cyclicvoltammetry, GOD shows the redox reaction at the potential below -0.6Y vs. Ag/AgCI. That leads to new peaks in the cyclicvoltammograms in additional to typical PPy peaks. The pH of electrolyte solution during potential swing decreased to 4.4, and then increased to 10. That suggests the redox of GOD for the cycling. As the concentration of GOD was increased, the anodic wave of the new peaks was strong as much as increased. GOD obstructs the diffusion of electrolyte anion because of its net chain. Insulating property of GOD is cause that it made the faradic impedance of complex large in charge transfer. It suggests that increase of the concentration of GOD be against electrochemical coupling. Therefore, the concentration of GOD and electrochemical coupling should be dealt with each other. The apparent Michaelis-lenten constant ( K\`$_{M}$ ) was determined by 30.7 mmol d $m^{-3}$ fur the PPy/GOD complex. The value is of the same order of magnitude as that for soluble glucose oxidase from Aspergillus Niger.r.

• 대한금속재료학회지
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• 제46권6호
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• pp.370-376
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• 2008

The formation of anodic oxide film of titanium (Ti) was studied at a variety of electrolyte concentrations and current density to clarify their effects on morphology, microstructure and composition of Ti oxide layer. For the analysis of the Ti oxide films, a scanning electron microscopy (SEM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) were used. The results showed that the concentration of phosphoric acid played a crucial role in the crystalline structure of the Ti oxide layer while the current density gave a critical effect on the thickness and diameter of its pore. In particular, the crystalline anatase phase with a thickness larger than $2{\mu}m$, which is quite desirable for a dental implant application, could be readily prepared at the phosphoric acid concentration of 0.5 M and current density higher than $2.0A/dm^2$.

• 한국세라믹학회지
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• 제46권6호
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• pp.648-652
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• 2009

Ceramic fiber separator is the promising material for thermal battery system because it reduces the production cost and offers the potential to a new application compared to a pellet type electrolyte. The electrolyte separator for thermal battery should be easily handled and loaded a large amount of the molten lithium salt. Ceramic fibers were used as an electrolyte separator and the lithium based molten salts were infiltrated into the ceramic filters. Leakage of molten salt (several lithium salts) leads to short-circuit during the thermal battery operation. In this study, a uniform and fine SiOC mat with fibers ranging from 1 to 3 ${\mu}m$ was obtained by electrospinning of polycarbosilane and pyrolysis. The optimum spinning conditions for obtaining fine diameters of SiOC fiber were controlled by the solution composition and concentration, applied voltage and spinning rate, release rate by porosity. The pore structures of the ceramic filter and the melting properties of the lithium salts affected to the electrolyte loading and leakage. The importance of the fiber size and porosity and their control was discussed and the mechanical properties were also discussed.

• 대한임상검사과학회지
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• 제48권2호
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• pp.137-143
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• 2016

본 연구는 22명의 남자 아마추어 선수를 대상으로 100 km 울트라 마라톤에서의 전해질 대사 반응의 안전성을 평가하기 위해 실시하였다. 대상자의 평균 연령은 $50.91{\pm}4.77$세, $VO_2max$는 $48.19{\pm}6.43mL/kg/min$, 그리고 평균 경기 완주시간은 $829.64{\pm}89.31$분이었다. 혈액검사에 포함된 전해질 지표로는 칼슘, 무기인, 마그네슘, 소디움, 포타슘, 염소, 총이산화탄소, 음이온 차이, 혈장량 변화와 삼투압 농도를 경기 전, 50 km 지점, 경기 종료 직후 측정하였다. 본 연구결과 소디움 농도는 경기 전보다 50 km 지점에서 감소하였고 50 km 지점보다 100 km 지점에서 감소하였으나, 고나트륨혈증 및 저나트륨혈증은 나타나지 않았다. 100 km 울트라 마라톤 경기에서 다른 모든 전해질 지표들의 거리별 변화는 참고범위 내에서 이루어졌으며, 혈장량 변화는 나타나지 않았다. 결론적으로 아마추어 지구력 선수들의 전해질 대사에 있어서 경기중 통계적인 차이는 있었으나 임상적으로 의미 있는 삼투압 농도와 전해질의 변화는 나타나지 않았으며 안전한 경기로 나타났다.

• 전기화학회지
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• 제3권4호
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• pp.204-210
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• 2000

용융아연 도금 강판 제조시 용융아연 도금 bath중의 알루미늄 농도를 조절하는 것은 매우 중요하다 본 연구의 목적은 용융아연 도금욕 중 알루미늄 농도를 신속하게 측정할 수 있는 센서 개발을 위한 기초 data를 제공하는 것이다. $CaF_2$고체전해질과 3가지 종류의 참조극을 사용하여 $460^{\circ}C\~500^{\circ}C$의 순수한 용융아연 bath에서 불소포텐샬을 측정하였다. 용융 아연 중 알루미늄의 농도를 측정하기 위하여 다음과 같은 불소 이온 농담전지 센서를 구성하였다. $$(-)W|Zn-Al,\;AlF_3|CaF_2|Bi,BiF_3|W(+)$$ 알루미늄의 농도가 $0.984wt\%$이하인 Zn-Al bath의 온도를 $460\pm10^{\circ}C$로 유지하고 상기의 알루미늄 농도 센서를 이용하여 기전력을 측정하였다. 측정된 기전력 값으로부터 최소 자승 회귀분석법을 이용하여, 다음과 같은 알루미늄 농도와 기전력과의 관계식을 얻었다. $$E/mV=56.795log[\%Al]+1881.7\;R=0.9704$$,$$0.026wt\%{\leq}[\%Al]{\leq}0.984wt\%$$

• 대한화장품학회지
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• 제10권1호
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• pp.13-23
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• 1984

The fluorescence intensity rations (F2.F1) of excimer (F2) to monomer (F1) of pyrene were measured as a function of the concentration of sodium dodecyl sulfate (SDS). It was found that there were not gross changes in size and shape of sphere-shape micelles in the first micelle concentration, while at concentrations above the second critical micelle concentration (CMC) the micelles grew in size with increasing concentration. Fluorescence intensities of 8-anilinonaphthalene 1-sulfonate (ANS) were also monitored as a micellar probe with varying concentrations of SDS. Results suggested that a phase transition from sphere-shaped micelles to hemicapped rod-like micelles occurred at the second CMC (17). A general formula for the axial ratio of ellip-soil-shaped micelle in the first micelle concentration was suggested. According to this general formula, the axial ratio of SDS, sodium lauryl ether sulfate and sodium laurate were 1:1, 5:2, and 5:3, respectively. The electrolyte-induced phase transition from spherical to hemicapped rod-like micelles occurred and the size of hemicapped rod-like micelles grew with increasing electrolyte concentrations. The maximum concentrations of solubilzed benzene in sphere-shaped micelles and hemicapped rod-like micelles were measured by differential spectrohpotometry. The hemicapped rod-like micelles in the presence of electrolytes grew in size with increasing amount of benzene solubilized.