• 한국입자에어로졸학회지
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• 제6권4호
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• pp.151-164
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• 2010

Inorganic ions and water are major components of ambient fine particles. Water content in fine particles is mainly determined by ambient meteorological conditions and the concentrations of hygroscopic species such as inorganic ions. Thus, to reduce fine particle mass concentration, it is important to accurately estimate the relationship between water content and the concentration of ions in fine particles. Water content in fine particles in Seoul are estimated by using a gas/particle equilibrium model to understand the characteristics of fine particle mass concentration. In addition, sensitivity of fine particle mass concentration to the changes of particulate ionic species (sulfate, nitrate, and ammonium) is estimated. It was found that water content in Seoul is mostly determined by the concentrations of the hygroscopic ionic species, especially, sulfate and ammonium, and ambient relative humidity.

• 공업화학
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• 제27권1호
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• pp.86-91
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• 2016

Ionic liquid 기능화 및 메탈로센 촉매 담지를 위해 세 종류의 무정형 실리카와 SBA-15를 담체로 사용하였다. Ionic liquid가 표면 기능화된 실리카는 1,3-bis(cyanomethyl)imidazolium chloride의 염소 음이온과 실리카 표면의 OH 그룹 사이의 상호작용에 의해 합성되었다. 에틸렌 중합을 위해 ionic liquid가 기능화된 실리카에 메탈로센과 조촉매 methylaluminoxane(MAO)을 담지하였다. SBA-15와 비교하여 큰 기공 크기를 갖는 ionic liquid가 표면 기능화된 XPO-2412와 XPO-2410에 담지된 촉매는 기능화되지 않은 실리카에 담지된 촉매보다 높은 활성을 보였다. 그러나 SBA-15에 담지된 촉매는 ionic liquid의 표면 기능화 후에 활성이 감소하였다. 이는 ionic liquid와 메탈로센 촉매, 조촉매 MAO가 담지되면 기공의 크기가 크게 줄어들기 때문에 중합 시 에틸렌 모노머와 조촉매가 기공 내 촉매 활성점으로 확산하는데 제한을 받기 때문이다. 또한 실리카 표면의 OH 그룹의 농도 변화에 따른 촉매의 중합 활성에 대한 영향을 연구하였다. 무정형 실리카의 OH 그룹의 농도가 증가할수록 중합 활성도 증가하였으며 실리카에 담지된 촉매의 중합 활성은 ionic liquid 표면처리 후에도 유사한 경향을 보였다.

• 한국환경보건학회지
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• 제26권3호
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• pp.18-24
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• 2000

The collection of PM10 samples were collected by a PM10 hi-vol. air sampler from June, 1998 through May, 1999 in Kunsan located at western coastal region of Korea. We obtained 84 samples during sampling period. Samples were analyzed to quantify the concentration of ionic and metallic components such as SO42-, NO3-, Cl-, NH4+, K+, Na+, Mg2+, Zn, Cd, Cr, Pb and Fe. Seasonal variations of the concentrations by wind directions of each component were studied. We found that PM10 concentration had the highest level in winter and the lowest level in summer. When the wind direction is from west to east, the concentration of most ionic and metallic species were higher compared to reverse direction. That implied the effect of air pollutants from industrial area. Also, substantial amount of Na+ and Cl- were observed, which was assumed to the effect from the sea.

• 방사성폐기물학회지
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• 제18권4호
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• Journal of Nutrition and Health
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• 제11권3호
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• pp.37-42
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• 1978

Actomyosin and myofibril were extracted from Korean native Goat muscle with the Weber-Edsall solution. ATPase activities and physiochemical properties were measured. The results obtained were as follows; 1) Mg-activitied ATPase activity of actomyosin and myofibrill from Korean native Goat muscle exhibited a common biphasic response, a typical ATPase pattern, that is high at a low ionic strength and low at a high ionic strength. Actomyosin showed high activity than myofibrill. 2) Mg-activited ATPase activity of actomyosin from muscle increased extraction time 24 hours. 3) EDTA-enhanced ATPase activity of actomyosin was greater than myofibrill and low at the low ionic strength, high at the high ionic strength. The difference of the activity were shown great broad pattern at the after 0.3M KCI concentration. 4) Effect of EGTA on-ATPase activity of myofibrill and actomyosin from muscle was measured, the Mg-ATPase activity was markedly depressed. 5) Solubility of actomyosin from muscle began to solubilize at KCI concentration of 0.28M and solubilized completely at the KCI concentration of 0.3M.

• BioChip Journal
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• 제12권4호
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• pp.317-325
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• 2018

This paper investigated the effects of ionic strength in the medium on a preconcentrator for a protein sample with low concentration. The preconcentration chip was designed and fabricated using a polydimethylsiloxane replica through standard lithophotography. A glass substrate is silanized prior to functionalizing the nanoparticles for self-assembly at a designed region. Due to the overlap of electrical double layers in a nanofluidic channel, a concentration polarization effect can be achieved using an electric field. A nonlinear electrokinetic flow is induced, resulting in the fast accumulation of proteins in front of the induced ionic depletion zone, so called exclusion-enrichment effect. Thus, the protein sample can be driven by electroosmotic flow and accumulated at a specific location. The chip is used to collect fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) diluted in phosphate-buffered saline (PBS) buffer solution. Different concentrations of the buffer media were studied herein. Fluorescence intensity images show that the buffer concentration of 4 mM is more appropriate than all the other ones. The sample of FITC-BSA with an initial concentration of $10{\mu}M$ in the 4 mM PBS solution increases its concentration at the desired region by up to 50 times within 30 min, demonstrating the results in this investigation.

• Journal of Microbiology and Biotechnology
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• 제17권4호
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• pp.600-603
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• 2007

The effect of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate $([BMIM][BF_4])$, on the horseradish peroxidase (HRP)-catalyzed oxidation of 2-methoxyphenol (guaiacol) with hydrogen peroxide $(H_2O_2)$ was investigated. HRP maintains its high activity in the aqueous mixtures containing various concentrations of the ionic liquid and even in 90% (v/v) ionic liquid. In order to minimize the effect of solution viscosity on the kinetic constants of HRP catalysis, the enzymatic reactions in the subsequent kinetic study were performed in water-ionic liquid mixtures containing 25% (v/v) ionic liquid at maximum. As the concentration of $[BMIM][BF_4]$ increased for the oxidation of guaiacol by HRP, the $K_m$ value increased with a slight decrease in the $K_{cat}$ value: The $K_m$ value increased from 2.8 mM in 100% (v/v) water to 22.5mM in 25% (v/v) ionic liquid, indicating that ionic liquid significantly weakens the binding affinity of guaiacol to HRP.

• 한국대기환경학회지
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• 제20권6호
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• pp.803-810
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• 2004

Water contents in fine particles at Seoul and Gosan are estimated by using a gas/particle equilibrium model, SCAPE (Simulating Composition of Atmospheric Particles at Equilibrium). Also, sensitivity of particulate inorganic ionic concentrations on the total ionic species is estimated. Water content at Gosan is more sensitive to ambient relative humidity (RH) than Seoul. At both sites water content is most sensitive to sulfate concentration among sulfate, nitrate, and ammonium. Solid salts levels and compositions are also studied.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권1호
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• pp.37-41
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• 2001

HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds. On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppression RP-HPLC method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate (5-CMP) disodium salt, uridine-5-monophosphate disodium salt (5-UMP), guanosine-5-monophosphate disodium salt (5-GMP), inosine-5-monophosphate disodium salt (5-IMP), and adenosine-5-monophosphate disodium salt (5-AMP) were examined. Acetic acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by following: K = (k(sub)-1 + k(sub)0 (k(sub)B/k(sub)S)/(1 + (k(sub)B/k(sub)S) C(sub)B(sup)a), where C(sub)B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and this was buffer dependent.

• 한국의류학회지
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• 제28권6호
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• pp.854-861
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• 2004

To estimate dispersion stability of particles in anionic and nonionic surfactant mixed solution, suspending power was examined as functions of duration time of suspension, ionic and nonionic surfactant mixed ratio, surfactant concentration, kinds of electrolyte, ionic strength and mole numbers of oxyethylene additions to nonionic surfactant using $\alpha$-Fe$_2$O$_3$ particle as the model of particulate soil. The suspending power of anionic and nonionic surfactant mixed solution was relatively higher than that of anionic and nonionic surfactant single solution regardless of solution concentration. The suspending power was gradually decreased with increasing duration time of suspension. In the absence of electrolyte, the effect of surfactant concentration on suspending power was small but in solution with electrolyte, suspending power was lowest at 1 ％ surfactant concentration. With 1${\times}$10$^{-3}$ ionic strength and polyanionic electrolyte in solution, the suspending power was high but effects of oxyethylene mole number to nonionic surfactant on suspending power was small. Generally the suspending power was gradually increased with decreasing the particle size. Hence the suspending power was inversely related to the particle size.