• Journal of Life Science
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• v.12 no.6
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• pp.682-687
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• 2002

We analyzed improvement on the enzyme activity of CPase Taq by addition of various metal ions. The enzyme activity was increased more then four times by 1 mM cobalt ion and almost three times by 1 mM calcium ion. However, the active center metal zinc ion did not affect the enzyme activity. In order to investigate whether the active center metal affects the enzyme activity, zinc ion which is occupied the active center of the enzyme was replaced by cobalt ion which activates the enzyme activity very effectively. Since the cobalt ion in the active center of the cobalt-substituted CPase Taq did not affect the enzyme activity, it could act as the natal metal ion in the active center of the enzyme.

• Bulletin of the Korean Chemical Society
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• v.18 no.10
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• pp.1100-1104
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• 1997

Compounds containing a nitrone moiety were designed, synthesized and evaluated as a new type of active site zinc ligating substrate analog inhibitors for carboxypeptidase A. The kinetic results indicated that they are competitive inhibitors for the enzyme, supporting the design rationale that the oxygen of the nitrone forms a coordinative bond to the active site zinc ion. The present study demonstrates that nitrone is useful as a zinc coordinating ligand in the design of inhibitors for zinc containing proteolytic enzymes.

• Corrosion Science and Technology
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• v.5 no.2
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• pp.39-44
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• 2006

The dissolution amount of Zn plate was $0.058mg/cm^2$ in the non-magnetically treated solution, and was $0.059mg/cm^2$ in the magnetically treated solution after 24 hours of immersion. The magnetic treatment had no effect to corrosion of Zn plate as pH on surface was not recognized the difference. The addition of Zn(II) ion in the solution was prepared to the effects of corrosion and dissolution of Fe. The regularity was not obtained the effect of the magnetic treatment on the dissolution of Fe plate.

• Resources Recycling
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• v.10 no.3
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• pp.23-28
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• 2001

Zinc ion could be recovered from metal plating wastewater with the spent iron oxide catalyst which was used in the plant of Styrene Monomer(SM) production. The zinc was recovered more than 98.7% at higher than pH 2.0. The saturation magnetization of the spent catalyst is enough high as 59.4 emu/g to apply in the solid-liquid separation after treating the wastewater. The mechanism of zinc recovery with the iron oxide catalyst could be a electro-chemical adsorption at pH 3.0~8.5, and a precipitation as $Zn(OH)_2$ at higher than pH 8.5.

• Journal of the Korean Electrochemical Society
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• v.18 no.4
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• pp.161-171
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• 2015

High-yield zinc germanium oxide ($Zn_2GeO_4$) and zinc tin oxide ($Zn_2SnO_4$) nanowires were synthesized using a hydrothermal method. We investigated the electrochemical properties of these $Zn_2GeO_4$ and $Zn_2SnO_4$ nanowires as anode materials of lithium ion battery and sodium ion battery. The $Zn_2GeO_4$ and $Zn_2SnO_4$ nanowires showed excellent cycling performance of the lithium ion battery, with a maximum capacity of 1021 mAh/g and 692 mAh/g after 50 cycles, respectively, with a high Coulomb efficiency of 98 %. For the first time, we examined the cycling performance of $Zn_2GeO_4$ and $Zn_2SnO_4$ nanowires for sodium ion batteries. The maximum capacity is 168 mAh/g and 200 mAh/g after 50 cycles, respectively, with a high Coulomb efficiency of 97%. These nanowires are expected as promising electrode materials for the development of high-performance lithium ion batteries as well as sodium ion batteries.

• Journal of IKEEE
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• v.23 no.3
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• pp.904-909
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• 2019

Using the ion-beam irradiated indium zinc oxide (IZO) films which was cured at $100^{\circ}C$, uniform LC and homogeneous alignment of liquid crystal (LC) molecules was achieved. The IZO film was deposited on the glass substrate at the curing temperature of $100^{\circ}C$ and irradiated by the ion-beam which is an LC alignment method. To verify the LC alignment characteristics, polarizing optical microscope and the crystal rotation method were used. Additionally, it was confirmed that the LC cell with the IZO films had an enough thermal budget for high-quality LC applications. Field emission scanning electron microscope was conducted as a surface analysis to evaluate the effect of the ion-beam irradiation on the IZO films. Through this, it was revealed that the ion-beam irradiation induced rough surface with anisotropic characteristics. Finally, electro-optical (EO) performances of the twisted-nematic cells with the IZO films were collected and it was confirmed that this cell had better EO performances than the conventional rubbed polyimide. Furthermore, the polar anchoring energy was measured and a suitable value for stable LC device operation was achieved.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.137-142
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• 1991

A method is developed for the simultaneous determination of dissolved iron, copper, and zinc in rainwater. The method involves 25-fold evaporative concentration, ion chromatographic separation and subsequent spectrophotometric detection after post-column reaction with 4-(2-pyridylazo) resorcinol. Analytical sensitivities, being defined by the slopes of calibration curves, are 0.93, 0.54, and 0.11 Abs/ $\mu$g/ml for iron, copper, zinc, respectively. Detection limits render around a few tenth of one ng/ml. Precisions evaluated by replicate analysis of real sample are better than 10% RSD. Due to the lack of certified standards for rainwater, the accuracy of the method could not be assessed directly. However, the results of this method agree well with those by inductively coupled plasma mass spectrometry. Analytical results for a suite of Seoul rainwaters are presented herein.

• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.165-171
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• 2012

An experimental study of mass transfer to an amalgamated copper rotating disc electrode has been employed to determine an empirical correlation for the mass transfer rate in laminar flow. The study was performed in a three-electrodes configuration using 0.1 M boric acid and 0.1M potassium chloride as supporting electrolyte with Zn (II) concentration in the range (25-100 mg $dm^{-3}$). Polarization curves at different zinc ion concentration are reported. Hydrogen and oxygen reduction has also been considered.The diffusion coefficients and mass transfer coefficient were obtained using limiting diffusion current technique based on zinc ion reduction. A least squares analysis indicates that the laminar flow results for 13067 < Re > 57552 and 550 < Sc > 1390 can be correlated by the following equation with correlation coefficient (CR) equal to 0.98: $sh=0.61Re^{0.5}Sc^{1/3}$.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.309-312
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• 2002

Exogenous glutamine synthetase (GS) was used efficiently as a selectable marker to identify successful transfectants for the production of erythropoietin (EPO) in Chines hamster ovary (CHO-K1) cells in the absence of glutamine. Inclusion of methionine sulphoximine (MSX), an inhibitor of glutamine synthetase, enabled further selection of clones with relatively high levels of transfected glutamine synthetase and EPO genes which were coupled together. In this study, a new cell line was established by using GS system and enhancement of EPO production by zinc ion was evaluated using the transfected CHO-K1 cell line under normal condition. It was found that EPO production from CHO-K1 cells was enhanced 40% when the optimal amount of zinc ion was added.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.555-562
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• 2002

Isomers based on the RS and EZ geometrical isomerism of the neutral, deprotonated species of HMPAO and their complexes with zinc(Ⅱ) ion have been investigated by semiempirical AM1 optimization method. The Hartree-Fock energies on AM1 geometries o f HMPAO species were calculated with HF/6-31G* methods. Twenty-two isomers of the neutral and twenty isomers of the deprotonated species of HMPAO have been found. The presence of four EE-series isomers of both zinc(Ⅱ) complexes with the neutral and deprotonated HMPAO have been expected and the SREE typical isomer of both types of complexes is the most stable isomer. Energies of complexation of zinc(Ⅱ)/HMPAO isomers with AM1 geometries were calculated by HF/ 6-31G*method. Due to the complexations with zinc(Ⅱ), the structural reorganizations of some isomers of the neutral HMPAO have been occurred. The optimized geometrical parameters of the related conformations have been discussed in terms of their stabilities and existences.