• Bulletin of the Korean Chemical Society
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• 제29권3호
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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.

• 한국환경과학회지
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• 제10권2호
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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.

• 멤브레인
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• 제12권1호
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• pp.51-53
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• 2002

Poly(vinyl alcohol) (PVA)/sulfosuccinic acid $(SSA)-H^+$ 막은 1가 이온 $Li^+, Na^+,K^ + 2$가 이온 $Mg^{2+}, Ca^{2+},Ba^{2+}, 3$가 이온 $Al^{3+}$로 치환하였다. 또한 $Li^{+}$의 경우 치환도를 화하였다. 금속이온치환의 효과를 알아보기 위하여 Diffusion cell을 이용한 메탄올투과도를 측정하였다. 메탄올투과도를 1가 이온의 경우는 'Salting-out'효과뿐 아니라 electrostatic 가교와 금속 이온의 반응성에 의존한다고 사료되었다. 또한 $Li^+$이온이 경우 치환도에 비례하여 메탄올 투과도가 감소하였는데 이는 'Salting-out'효과에 기인한다고 사료되어진다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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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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• 제13권1호
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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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• 제16권4호
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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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• 제41권5호
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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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• 제22권7호
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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.

• 대한화학회지
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• 제38권2호
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• pp.122-128
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• 1994

거대고리 리간드는 금속이온과 선택적으로 결합하는데, 이를 이용하여 에멀젼 액체막을 통한 금속이온의 이동에 관하여 연구를 수행하였다. 금속이온은 유기층에 있는 운반체에 의하여 source phase에서 recevinng phase으로 이동한다. 운반체로는 거대고리 리간드인 $DBN_3O_3$를 사용하였다. 여기에서 에멀젼 액체막을 통한 금속이온의 이동에 관한 요인과 어떤 금속이온의 선택적 분리에 관하여 검토하였다. 금속이온과 거대고리 리간드 그리고 금속이온과 recevinng phase내에 있는 음이온에 대한 안정도 상수를 금속이온의 선택적 이동에 대한 척도로 조사하였다. 납이온이 혼합 용액에서 다른 금속이온보다 높은 이동속도를 나타내었다. Recevinng phases내의 음이온이 금속이온의 이동에 중요한 역할을 한다.Recevinng phases내에 있는 $NO_3^-$을 $S_2O_3^{2-}$대치하면 이동량이 증가함을 보였는데 이는 $Pb^{2-}-S_2O_3^{2-}$상호작용이 $Pb^{2+}-NO_3^-$상호작용보다 크기 때문이다.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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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.