• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.86-90
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• 2011

The effects of cations are very important in field-effect transistors (FETs) type DNA sensors detecting the intrinsic negative charge between single-stranded DNA and double-stranded DNA without labeling, because the intrinsic negative charge of DNA is neutralized by cations in electrolyte solution. We consider the Debye length, which depends on the concentration of cations in solution, to detect DNA hybridization based on the intrinsic negative charge of DNA. The Debye length is longer in buffer solution with a lower concentration of NaCl and the intrinsic negative charge of DNA is more effective on the channel surface in longer Debye length solution. The shifts in the gate voltage by DNA hybridization with complementary target DNA are 21 mV in 1 mM NaCl buffer solution, 7.2 mV in 10 mM NaCl buffer solution, and 5.1 mV in 100 mM NaCl buffer solution. The sensitivity of FETs to detect DNA hybridization based on charge detection without labeling depends on the Debye length.

• Clean Technology
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• v.20 no.1
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• pp.51-56
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• 2014

In this study, PSf-$Al(OH)_3$ beads were prepared by immobilizating aluminum hydroxide $Al(OH)_3$ with polysulfone (PSf). The removal experiments of the fluoride ions by PSf-$Al(OH)_3$ beads were conducted batchwise and the parameters such as pH, initial fluoride concentration, and coexisting ions were investigated. The maximum removal capacity obtained from Langmuir isotherm was 52.4 mg/g and the optimum pH region of fluoride ions was in the range of 4 to 10. The removal process of fluoride ions by PSf-$Al(OH)_3$ beads was found to be controlled by both external mass transfer at the earlier stage followed by internal diffusion at the later stage. The presence of coexisting anions such as $HCO_3{^-}$, $SO{_4}^{2-}$, $NO_3{^-}$, and $Cl^-$ had a negative effect on removal of fluoride ions by PSf-$Al(OH)_3$ beads.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.314-322
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• 2004

The production of a glucan was affected by the concentration of ions and buffer solutions, and nutrients in an oral cavity. In this study, the effects of ions and buffer solutions on the mRNA expression of gtfD gene in Streptococcus mutans, an important causative agent of dental caries, were investigated by Fluorescent in situ hybridization(FISH). At first, ions and buffer solutions had little effect on the multiplication of Streptococcus mutans. The green fluorescence according to the mRNA expression of gtfD gene was detected in the BHI broth containing 1% sucrose. The intensities of the green fluorescence were strong at 0.25mM of $CaCl_2$. Little fluorescence was detected by the addition of KCl, except far 10mM KCl at which fluorescence intensities were similar to those of the control. Fluorescence intensities were weak at each concentration of $MgCl_2$ when compared to the control. As for buffer solutions, fluorescence intensities were similar to those of the control at each concentration of buffer solutions, except that they were little detected at 100mM of potassium phosphate.

• Membrane Journal
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• v.29 no.6
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• pp.355-361
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• 2019

We studied the removal of barium ions that may be contained in industrial wastewater using the existing capacitive deionization (CDI). The 30 mg/L BaCl₂ (barium chloride dihydrate) solution was used as the feed solution, and the flow rate was set to 10 mL/min. The adsorption conditions were varied from 1.2 V to 3, 5 and 7 min, and the desorption conditions were -1, -1.5, -2 V and 1, 2 and 3 min, respectively, to select the most efficient conditions. As a result, barium ion removal efficiency of 64.4% was obtained under the adsorption conditions of adsorption of 1.2 V/7 min and the desorption -1 V/1 min. For the desorption voltages and time, under the same experimental conditions, the removal efficiency of CDI for 30 mg/L NaCl aqueous solution with the same concentration as barium showed 69.9% removal efficiency under the adsorption conditions of and the desorption conditions of 1.2 V/7 min desorption -1 V/1 min, respectively.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.303-310
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• 2017

This paper is to understand the settling properties of cohesive sediments under effects of ions in turbulent flow. The experiments were conducted using a miniature annular flume(mini flume) with a free water surface. Silica was used as sediment of experiment. The suspended concentrations were measured by using a CCD-Camera. Settling of silica($SiO_2$) was allowed to occur under various shear stresses in a concentration of 7g/L. At condition of pH 4.2 and high NaCl concentration, the floc size D of silica was larger than D at condition of pH6.8 with the bed shear stress increasing. The settling velocity $W_s$ of silica was higher at condition of 10g NaCl/L than $W_s$ at condition of pH4.2. Comparison of measured concentration-time curves and concentration-time curves calculated by this study showed similar tendency in flow under effects of ions.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.153-157
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• 2016

In this study, three different metal-containing ionic liquid catalysts were prepared by metal insertion and characterized by various physicochemical analytic methods. The catalytic performance of the metal containing ionic liquids in the cycloaddition of $CO_2$ with propylene oxide (PO) to produce propylene carbonate (PC) was investigated under the solvent free condition. The order of approximate rate constants ($K_{app}$) for the metal containing ionic liquid catalysts was $(MeIm)_2ZnCl_2$, > $(MeIm)_2FeCl_2$ > $(MeIm)_2CuCl_2$. These results are in accord with the experimentally obtained activity order of the different metal containing ionic liquid catalysts.

• Journal of the Korean Electrochemical Society
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• v.25 no.3
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• pp.113-118
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• 2022

In this study, the effect of polyethylene glycol (PEG) on Cu electrodeposition was analyzed using cyclic voltammetry. The adsorption of PEG was affected by the specific adsorption of sulfate ion (SO₄^2-) or chloride ion (Cl^-). In SO₄^2--based plating solution, the adsorption of PEG was limited by the adsorbed SO₄^2-. Accordingly, the adsorbed PEG could suppress the electron transfer for Cu electrodeposition, but its effect was not significant. Meanwhile, in the plating solution composed of perchlorate ion (ClO₄^-) which does not specifically adsorb on Cu surface, a strong suppression effect of PEG was observed and it was proportional to the molecular weight of PEG. On the other hand, when Cl^- was specifically adsorbed on Cu surface, the suppression effect of PEG was enhanced because PEG and Cl^- formed an interrelated adsorbate. The synergetic effect of PEG and Cl^- depended on the composition of the plating solution, which means that the synergy between PEG and Cl^- is based on the physical interaction. For example, the hydrophobicity of PEG plays an important role in the interaction, as the suppression effect of PEG derivative having a hydrocarbon tail was further enhanced with the addition of Cl^-.

• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.341-346
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• 2016

The AMY2B gene, encoding human pancreatic ${\alpha}$-amylase isozyme (HPA II), was expressed in Pichia pastoris, and the effects of chloride ions on HPA II activity toward starch substrates were investigated. As seen with chloride ion-dependent ${\alpha}$-amylases-including HPA I, the isozyme of HPA II-chloride ions increased enzyme activity and shifted the optimal pH to an alkaline pH. The activity enhancement by chloride was more significant at pH 8 than that at pH 6, suggesting that the protonation state of the general acid/base catalyst of HPA II was important for the hydrolysis of starches at an alkaline pH because of the increase in its $pK_a$ by chloride ions. The turnover values for cereal starches as the substrates markedly increased in the presence of chloride by up to 7.2-fold, whereas that for soluble starch increased by only 1.7-fold. Chloride inhibited substrate hydrolysis at high substrate concentrations, with $K_i$ values ranging from 6 to 15 mg/mL.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.533-544
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• 2021

Ion exchange (IX) performance on the exchanger bed is essentially evaluated for the generation of ultrapure water in electronics and chemical industries and for the corrosion control in nuclear power plants. The breakthrough characteristics of IX bed with multi-component were investigated with both cation- and mixed-IX beds of H- and ETAH-form for four kinds of cation exchange resins by using the combined solution of ethanolamine (ETA) and ammonia (NH₃) at trace NaCl. Unlike major components (ETAH⁺ and NH₄⁺ ), the phenomena of breakthrough and overshooting at bed outlet were not observed by Na⁺ over the test period (> 3 times theoretical exchange capacity of IX bed). The breakthrough from H-form resin bed was sequentially reached by ETAH⁺ and NH₄⁺, while the overshooting was observed for ETAH⁺ at the breakthrough of NH₄⁺. NH₄⁺ was 51.5% higher than ETAH⁺ in terms of the relative selectivity determined with the width of breakthrough zone. At the increased concentration of Na⁺ at bed inlet, the selectivity and the overshooting were decreased and increased, respectively. Na⁺ leakage was higher from ETAH-form resin bed and was not identical for four kinds of cation-exchange resins, which may be reduced by improving the intrinsic property of IX resin.

• Journal of the Korean Chemical Society
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• v.28 no.4
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• pp.238-243
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• 1984

Three component $Ag_2S-PbS-PbMoO_4$ electrodes have been prepared and evaluated for sensitivity to molybdate. The 64.5 : 14.0 : 21.5(w/w%) composition is superior in terms of potentiometric response, stability, rapidity of response and reproducibility. Testing was done over the concentration range of $10^{-1}{\sim}10^{-5}M\;MoO_4^{2-}\;in\;0.1F\;NH_4Ac-NH_4OH$ buffer solution at pH 7.95 with constant ionic strength. $I^-,\;Cl^-,\;Br^-\;and\;CN^-$, etc. interfere.