• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.356-356
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• 2007

Plasma immersion ion beam deposition (PIIBD) technique is a cost-effective process for the deposition of diamond like carbon thin film, the possible solid lubricant on large surface and a complex shape. We used PIIB process for the preparation of DLC thin film on $Al_2O_3$ with deposition conditions of deposition temperature range $200^{\circ}C$, working gas pressure of 1.310-1Pa. DLC thin films were coated by $C_2H_2$ ion beam deposition on $Al_2O_3$ after the ion bombardment of SiH4 as the bonding layer. Energetic bombardment of $C_2H_2$ ions during the DLC deposition to ceramic materials generated mixed layers at the DLC-Si interface which enhanced the interface to be highly bonded. Wear test showed that the low coefficient of friction of around 0.05 with normal load 2.9N and proved the advantage of the low energy ion bombardment in PIIBD process which improved the tribological properties of DLC thin film coated alumina ceramic. Furthermore, PIIBD was recognized as a useful surface modification technique for the deposition of DLC thin film on the irregular shape components, such as molds, and for the improvement of wear and adhesion problems of the DLC thin film, high temperature solid lubricant.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.152-156
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• 2019

The removal property of magnetic zeolite for the adsorption of aqueous ammonium ion was examined in this work. The surface modified magnetic zeolite was produced by hydrothermal synthesis. The complex of zeolite and $Fe_3O_4$ was established by the observation of SEM and XRD analysis and less than 12.6% of $Fe_3O_4$ content in magnetic zeolite was observed in the form of $Fe_3O_4$ particles. The optimum pH of adsorption was shown around 8 and the maximum adsorption linearly decreased with the increase of $Fe_3O_4$ content. The adsorption isotherm for aqueous ammonium ion was approximated by Langmuir equation. The developed surface modified magnetic zeolite adsorbent was recommended to control the nitrogen pollution for wetland environment system.

• Analytical Science and Technology
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• v.20 no.3
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• pp.213-218
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• 2007

Copper(II) ion was measured with the use of a perfluorinated sulfonated polymer-ethylenediamine (nafion-en) modified glassy carbon electrode. The electrode mechanism was based on the chemical reactivity of an immobilized layer (nafion-en) to yield complex $[Cu(en)_2]^{+2}$. The reduction potential peak by differential pulse voltammetry(DPV) was observed at -0.4402V(${\pm}0.0050V$) (vs. Ag/AgCl). The linear calibration curve was obtained from $1.0{\times}10^{-6}$ to $1.0{\times}10^{-4}M$ copper(II) ion concentration, and the detection limit(3s) was $1.96{\times}10^{-6}M$.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.96-101
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• 1988

It is important to assess the effects of ionic strength and type of anions when studying the adsorption of heavy metals on zeolite because the background salt may complex with heavy metals and compete for adsorption sites. This experiment was carried out to determine the effect of ionic strength and anion species($Cl^-$, $SO^{2-}\;_4$, and $ClO^-\;_4$) on heavy metal adsorption. Heavy metal adsorption by zeolite from solutions in the range of 10 to 50ppm was studied in the presence of NaCl, $Na_2SO_4$ and $NaClO_4$, with different concentrations. The ionic strength ranged from 0.01 to 1.00. Adsorption of heavy metal cations could be described by the Freundlich isotherm equation. Increasing the ionic strength of equilibrium solutions, the amounts of heavy metal adsorbed on the zeolite surfaces decreased in all three of the anion systems. This fact could be attributed to the competition of background salt cation and the decrease in initial activity of heavy metal cations. In the presence of Cl anion, less adsorption resulted than in the presence of $SO_4$ or $ClO_4$ anions of the same ionic strength, indicating the presence of uncharged and negatively charged complexes of heavy metal with Cl ligands.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.687-691
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• 1993

Complexation of $Cd^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions with four cryptands were studied by potentiometry and solution calorimetry in various weight percent methanol-aqueous solvent at 25${\circ}$C under $CO_2$free nitrogen atmosphere. The stabilities of the complexes were dependent on the cavity size of macrocycles. The $Hg^{2+}$ ion stability constants are higher than those of $Cd^{2+}\;and\;Pb^{2+}$ ion. All the cryptands formed complexes having 1 : 1 (metal to ligand) mole-ratio except for $Hg^{2+}-L_1$ (cryptand 1,2b: 3,5-benzo-9,14,17-trioxa-1,7-diazabicyclo-(8,5,5) heptadecane) and $Cd^{2+}-L_2$ (cryptand 2,2b: 3,5-benzo-10,13,18,21-tetraoxa-1,7-diazabicyclo (8,5,5) eicosane) complexes. $Hg^{2+}-L_1$ complex was a sandwitch type, and the $Cd^{2+}-L_2$ complex showed two stepwise reactions. Thermodynamic parameters of the $Cd^{2+}-L_2$ complex were $6.08(log\;K_1)$, -7.28 Kcal/mol $({\Delta}H_1)$, and $4.78\;(log\;K_2)$, -4.62 Kcal/mol $({\Delta}H_2)$, respectively, for 1 : 1 and 2: 1 mole-ratio. The sequences of the selectivity were increased in the order of $Hg^{2+}\;>Pb^{2+}\;>Cd^{2+}$ ion for $L_3\;and\;L_4$ macrocycles, and the $L_2$-macrocycle has a selectivity for $Cd^{2+}$ ion relative to $Zn^{2+},\;Ni^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions. Thus, it is expected that the $L_2$ can be used as carrier for seperation of the post transition metals by macrocycles-mediated liquid membrane because $L_2$ is not soluble in water, and the difference of stability constants of the metal complexes with $L_2$ are large as compared with the other transition metal complexes. The $^1H\;and\;^{13}C-NMR studies indicated that the nitrogen atoms of cryptands have greater affinity to the post transition metal ions than the oxygen atoms, and that the planarities of the macrocycles were lost by complexation with the metal ions because of the perturbation of ring current of benzene molecule attached to macrocycles and counter-anions.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.253-261
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• 2002

Vibrational properties of ferrocyanide complex ion, $[Fe(CN)_6]^{4-}$ , have been studied based on the force constants obtained from the density functional calculations at B3LYP/$6-31G^{\ast\ast}$ level by means of the normal mode analysis using new bond angle and linear angle internal coordinates recently developed. Vibrations of ferrocyanide were manipulated by twenty-three symmetry force constants. The angled bending deformations of C-Fe-C, the linear bending deformations of Fe-C${\equiv}$N and the stretching vibrations of Fe-C have been quantitatively assigned to the calculated frequencies. The force constants in the internal coordinates employed in the modified Urey-Bradley type potential were evaluated on the density functional force field applied, and better interaction force constants in the internal coordinates have been proposed. The valence force constants in the general quadratic valence force field were also given. The stretch-stretch interaction and stretch-bending interaction constants are not sensitive to the geometrical displacement in the valence force field.

• Microbiology and Biotechnology Letters
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• v.10 no.4
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• pp.283-288
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• 1982

Trypsin inhibitor produced by Streptomyces sp. was investigated its reactive characteristics against trypsin. The mode of inhibition against trypsin was mixed type of non-competitive and competitive with casein, and enzyme-inhibitor complex was formed rapidly. The inhibitory activity was increased by the addition of isoleucine and depressed by silver, mercuric or cupric ion. And when egg albumin or hemoglobin was used as substrate for trypsin, the inhibition ratio was changed. The inhibitor inhibited coagulation of blood of bovine.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3547-3552
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• 2013

Single crystal EPR and optical studies of a mixed ligand zinc(II) complex doped with VO(II) ion is carried out to establish the structural properties. The angular variation of vanadyl hyperfine lines indicates a single site, with spin Hamiltonian parameters as: $g_{xx}=1.985$, $g_{yy}=1.979$, $g_{zz}=1.943$; $A_{xx}=8.71$, $A_{yy}=6.41$ and $A_{zz}=17.80$ mT. By comparing the direction cosines of principal g and A values with the direction cosines of metalligand bonds, it has been confirmed that the vanadyl ion has entered the lattice interstitially. The exact interstitial position of VO(II) in host lattice has been calculated using the fractional coordinates of atoms in the host lattice out of many assumptions. The EPR and optical data have been confirmed to obtain various bonding parameters, from which the nature of the bonding in the complex is discussed. FT-IR confirms the formation of structure of host lattice.

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.593-600
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• 2007

Aluminum was anodized in a $H_2SO_4$ solution, and titanium (IV) oxide ($TiO_2$) was electrodeposited into nanopores of anodic porous alumina in a mixed solution of $TiOSO_4$ and $(COOH)_2$. The photocatalytic activity of the prepared film was analyzed for photodegradation of methylene blue aqueous solution. Consequently, we found it was possible to electrodeposit $TiO_2$ onto anodic porous alumina, and synthesized it into the nanopores by hydrolysis of a titanium complex ion under AC 8-9 V when film thickness was about $15-20{\mu}m$. The photocatalytic activity of $TiO_2$-loaded anodic porous alumina ($TiO_2/Al_2O_3$) at an impressed voltage of 9 V was the highest in every condition, being about 12 times as high as sol-gel $TiO_2$ on anodic porous alumina. The results revealed that anodic porous alumina is effective as a substrate for photocatalytic film and that high-activity $TiO_2$ film can be prepared at low cost.

• Journal of the Korean institute of surface engineering
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• v.46 no.2
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• pp.87-92
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• 2013

Viscosities of $LaCl_3$-CsCl binary melts were measured by the capillary method over the range of their liquidus temperatures to about 1200 K. The cell constant were determined by using pure water. The results obtained are summerized as follows: Viscosities of melted $LaCl_3$ were decreased with the content of CsCl for all over the composition range of binary melts. Composition versus viscosity relation for the binary melt showed a non-linear relationship from the additivity line and the deviations showed a maximum value at about 60 mol% CsCl. This suggest the existence of the complex ion of $LaCl_4{^-}$ in the melt. Activation energy for the viscous flow of the binary melts decreased monotonously with the increasing content of CsCl after a few increasement till 40 mol% CsCl. All of these results were the resemble with the viscosities of $LaCl_3$-NaCl binary melts.