• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.541-545
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• 2008

Stable molecular isomers were calculated for the azobenzene crown ether p-tert-butylcalix[4]arene (1) in the host and their alkali-metal-ion complexes. The structures of two distinct isomers (cis and trans) have been optimized using DFT B3LYP/6-31G(d,p) method. Trans isomer of 1 is found to be 11.69 kcal/mol more stable than cis analogue. For two different kinds of complexation mode, the alkali-metal-cation in the crown-ether moiety (exo) has much better complexation efficiency than in the benzene-rings (endo) pocket for both isomers of 1. Sodium ion has much better complexation efficiency than potassium ion in all kinds of complexation mode with host 1. The Na+ complexation efficiency of the trans-complex (1) in the exo-binding mode is 8.24 kcal/mol better than cis-exo analogue.

• Journal of Environmental Science International
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• v.10 no.2
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• pp.153-158
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• 2001

The biosorption abilities of different parts of waste brown seaweeds and their derivatives to remove heavy metals (Cd, Zn, Pb, Cu, Fe, Ni, Mn) from waste were evaluated. The two parts of waste brown seaweeds (Undaria pinnatifida) were stems and sporophyls, and the brown seaweed derivatives were alginic fibers, active carbon added alginate(AC-alginate) and dealginate. The abilities of the sporophyls to adsorb the heavy metal ions were higher than those of stems, and those of alginates were slightly higher than those of dealginate in single ion solution. With decreasing the size of biosorbents, the velocity and the amount of adsorption increased. The abilities of alginate to remove the heavy metal ions increased in multi-ion solutions by adding active carbon to alginate. The selectivity of these biosorbents(alginate, AC-alginate) to lead ion was highest and to manganese ion was lowest.

• Membrane Journal
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• v.12 no.1
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• pp.51-53
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• 2002

The hydrogen ions in poly (vinyl alcohol) (PVA)/sulfosuccinic acid (SSA) membranes substiuted with $Li^+, Na^+, and K^+/ $of monvoalent metal ions, $Mg^{2+}, Ca^{2+} and Ba^{2+}$ of divalent metal ions, and $Al^{3+}$ of trivalent metal ion. In addition, $Li^+ ions were exchanged with varing reaction time. The effects of metal ions exchanged were investigated in terms of methanol permeability -uling diffusion cell. The methanol permeabilies decreased in the sequence of $Na^+, Li^+ and K^+$ and this might be due to the 'Salting-out' effect while the methanol permeabilities for divalent and trivalent ion-substituted membranes were affected by the combined effects of salting-out, eletrostatic crosslinking and extent of metal ion substiution. As for $Li^+$ ions, methanol permeabilities of PVA/SSA membranes decreased in proportion to the degrees of subsituted $Li^+$ ions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.229-229
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• 2012

Adhesion of Copper film on the aluminum oxide layer formed by anodizing an aluminum plate was enhanced by applying ion beam mixing method. Forming an conductive metal layer on the insulating oxide surface without using adhesive epoxy bonds provide metal-PCB(Printed Circuit Board) better thermal conductivities, which are crucial for high power electric device working condition. IBM (Ion beam mixing) process consists of 3 steps; a preliminary deposition of an film, ion beam bombardment, and additional deposition of film with a proper thickness for the application. For the deposition of the films, e-beam evaporation method was used and 70 KeV N-ions were applied for the ion beam bombardment in this work. Adhesions of the interfaces measured by the adhesive tape test and the pull-off test showed an enhancement with the aid of IBM and the adhesion of the ion-beam-mixed films were commercially acceptable. The mixing feature of the atoms near the interface was studied by scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy.

• Journal of Electrochemical Science and Technology
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• v.13 no.1
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• pp.71-77
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• 2022

Metal halide perovskites are promising photovoltaic materials, but they still have some issues that need to be solved. Hysteresis is a phenomenon that strongly is correlated with ion migration; thus, a fast, easy, and low-temperature method for measuring ion migration is required. Through selective blocking, ion migration can be measured separately, apart from electron migration. In this study, ion migration in metal halide perovskites was measured using a vertical device. At different temperatures, ionic activation energies were obtained for a range of perovskite compositions such as MAPbI₃, FAPbI₃, CsPbI₃, and MAPbBr₃. By comparing the measured ionic activation energies with the theoretical values, we conclude that among other possibilities, I^- is the migrating ion in MAPbI₃, FAPbI₃, CsPbI₃, and Br- is the migrating in MAPbBr₃.

• Bulletin of the Korean Chemical Society
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• v.16 no.4
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• pp.316-320
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• 1995

The incorporation of metal ion into the Langmuir-Blodgett (LB) film of an itaconate copolymer was investigated. The polymer was prepared via radical copolymerization of monooctadecyl itaconate with triethyleneglycol methyl vinyl ether. The metal ions employed were Na+, Cs+, Mg2+, Fe2+, Al3+, and Fe3+. The surface pressure-area isotherms indicated that all the monolayers studied on subphases with metal ions showed more expanded areas than that observed on pure water. The monolayers showed an irreversible collapse behavior. The collapse pressure of the monolayers was low on subphases containing trivalent metal ions. From the FT-IR spectra by reflection and transmission modes, the formation of carboxylate salts and the uprisen orientation of the pendant against substrate surface in the polymer LB film were determined. It was estimated by XPS measurement that ca. 13.1 repeat units of the polymer contain one Na+ ion, while one Mg2+ ion corresponds to 5.9 carboxyls.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.709-714
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• 2009

An ion implanter, which can serve as a metal-ion supply, has been constructed and performance tested. Copper ions are generated and extracted from a Bernas ion source with a heating crucible that provides feed gases to sustain the plasma. Sable arc plasmas can be sustained in the ion source for a crucible temperature in excess of $350^{\circ}C$. Stable extraction of the ions is possible for arc Currents less than 0.3 A. Arc currents increase with the induced power of a block cathode and the transverse field in the ion source. $Cu^+$ ions in the extracted beam are separated using a dipole magnet. A $20{\mu}A$ $Cu^+$ ion current can be extracted with a 0.2 A arc current. The ion current can support a dose of $10^{16}ions/cm^2$ over an area of $15\;cm^2$ within a few hours.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.673-677
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• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the reactions of 8-(5-nitroquinolyl) 3-furoate with alkali metal ethoxides in anhydrous ethanol. The plot of kobs vs the concentration of alkali metal ethox ides is linear for the reactions performed in the presence of a complexing agent, 18-crown-6 ether, but exhibits upward curvatures for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions in this study behave as catalysts. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M + ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M + /kEtO-) was found to be 1.7, 3.4 and 2.5 for the reaction of 8-(5-nitroquinolyl) 3-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, 1.8, 3.7 and 2.4 for that of 8-(5-nitroquinolyl) benzoate, and 2.0, 9.8 and 9.3 for that of 8-(5-nitroquinolyl) 2-furoate with EtO- Li+ , EtO- Na+ and EtO- K+ , respectively. A 5-membered chelation at the leaving group is suggested to be responsible for the catalytic effect shown by alkali metal ions.

• Journal of the Korean Chemical Society
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• v.38 no.2
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• pp.122-128
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• 1994

Macrocyclic ligand has been known to selectively bind with metal ions so that ability applied for the transport of metal ions across the emulsion liquid membrane in this study. The metal ions are transproted from the source phase to the receiving phase by the carrier of the organic phase. Several factors involved in the transport of metal ions acrose the emulsion membrane we reported here and these factors provided the informations for the selective seperation of some metal ion. Stability constants for cation-macrocyclic ligand and metal ion-anion receiving phase interaction are examined as parameters for the prediction of metal ion transport selectivities. $Pb^{2+}$ was transported higher rates than the other metal ions in the mixture solution. The interaction of metal ion to anion in receiving phase is important. $S_2O_3^{2-}$- in replacement of $NO_3^-$ in the receiving phase enhances the transport of $Pb^{2-}$since $Pb^{2-}-S_2O_3^{2-}$interaction is greater than $Pb^{2+}-NO_3^-$ interaction.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.716-720
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• 2001

To test the metal ion effect, hydrolysis experiments for two cellobiohydrolases (CBHⅠ and CBH Ⅱ) from Trichoderma reesei have been carried out in the presence of 10 mM metal ions, such as Cu++, Mn++, Ca++, Hg++, Ba++, Pb++, and Cd++. The addition of Mn++, Ba++, and Ca++(10 mM) during the hydrolysis of Avicel PH 101 caused an increase in the total reducing sugar (TRS) for CBH Ⅰ by 142, 135, and 114 percent, respectively. Those for CBH Ⅱ increased by 177, 175, and 115 percent, respectively. The Mn++ was the most stimulatory metal ion, whereas Hg++ was the most inhibitory metal ion. The adsorption experiments were performed to investigate how the influence of Mn++ and Hg++ on the hydrolysis is related to the adsorption of cellobiohydrolases on cellulose. The increase in TRS during hydrolysis by adding Mn++ caused an increase in adsorption affinity (Kad) and tightness (ΔHa). While, the decrease of TRS during hydrolysis by adding Hg++ caused a decrease in the adsorption affinity (Kad) and tightness (ΔHa). These results indicate the changes in the tightness and affinity of adsorption by adding metal ions play a crucial role in the degradation of the microcrystalline cellulose.