• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.250-251
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• 2014

This study introduces a simple deposition of $Cu_2O$ thin films with surface morphologies composed of columns, submicron-rods and submicron-branches on glass substrate from metallic Cu targets by tailoring the $Ar/O_2$ ratios during the sputtering. The obtained samples were used to fabricate gas sensor. The $H_2S$ sensing properties of the sensors at working temperatures from $100^{\circ}C$ to $300^{\circ}C$ were studied, in which $Cu_2O$ submicron-branches performed the best sensing property comparing with the rest morphologies. A transformation of $Cu_2O$ to $Cu_2S$ and CuS was consider as a main factor to the sensing mechanism of the sensors.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.36-41
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• 1998

In this study, the extraction of Co(Ⅱ) and Cu(Ⅱ) into chloroform solution of dithizone, distribution ratios, extractabilities and extraction rate constants of the metal complexes were compared in each case with which thiocyanate ion was or not used as the auxiliary ligand. The use of the thiocyanate ion increased threefold the distribution ratio for Co(Ⅱ) complex in a basic solution and twofold for Cu(Ⅱ) complex in a wide pH range. And the extractability was also augmented from about 90 to 99 for Co(Ⅱ) and from 95 to 99 for Cu(Ⅱ) in a given period. The extraction rate constants were $k_1\;:\;1.2{\times}10^5$, $k_2\;:\;1.34{\times}10^{17}\; mol^{-1}dm^3s^{-1}$ in case of Co(Ⅱ) and$k_1\;:\;1.1{\times}10^8$, $k_2\;:\;2.83{\times}10^{10}\; mol^{-1}dm^3s^{-1}$ in case of Cu(Ⅱ) on the extraction of dithizonate complexes into chloroform solution.

• Journal of the Korean Magnetic Resonance Society
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• v.8 no.2
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• pp.86-95
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• 2004

A Cu(I) complex with an asymmetric TTF derivative (CET-EDTTTF) is prepared from the slow-diffusion method using CET-EDTTTF and Cu(I)Br solutions and characterized by X-ray crystallography and EPR spectroscopy. Structural analysis shows Cu(I) ions are tetrahedrally coordinated to two bridging bromides, one terminal bromide, and one S atom from CET-EDTTTF. Detailed geometrical and EPR analysis identified that the dimmer molecule contains [Cu$_2Br_4]^{2-}$ anion between two [CET-EDTTTF]$^+$ radical cations. Single-crystal EPR investigation of the complex reveals that the ganisotropy is unusually big, compared to those of the previously reported TTF+ cation radicals, implying that there is significant contribution of the Cu d-orbital to the HOMO of the complex.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1621-1625
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• 2010

Recently, due to increase in the usage of toxic gas and inflammability gas, the ability to monitor and precisely measurement of these gases is crucial in preventing the occurrence of various accidents. CuO doped and undoped $WO_3$ thick films gas sensors were prepared using screen-printing method on alumina substrates. A structural properties of $WO_3$:CuO thick films had monoclinic phase and triclinic phase of $WO_3$ together. Sensitivity of $WO_3$:CuO sensor at 2000 ppm of $CO_2$ gas and 50 ppm of $H_2S$ gas was investigated. 4 wt% Cu doped $WO_3$ thick films had the highest sensitivity of $CO_2$ gas and $H_2S$ gas.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.1-6
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• 1979

The dipole moments for square planar and tetrahedral $[M(II)N_2S_2]$ type complexes are calculated, using the expansion method for spherical harmonics [M(II) = Co(II), Ni(II), Cu(II) or Zn(II)]. The calculated values of the dipole moments for these complexes are in the range of the experimental values. The possible structures for these complexes in benzene solution are discussed on the basis of the calculated dipole moments and the the magnetic properties.

• Clean Technology
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• v.8 no.1
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• pp.53-59
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• 2002

$Cu-CeO_2$ catalysts were prepared by co-precipitation and liquid phase oxidation (CP-LPO) and the prepared catalysts were examined as selective oxidation of carbon monoxide catalysts for the application of fuel cell vehicles. The prepared $Cu-CeO_2$ catalysts showed high reaction activity, but it was hard to find the correlation between the amount of Cu loaded and the reaction activities. As increase of the amount of Cu loaded, the micro pore structure of the catalyst was changed. It is due to the formation of solid solution between Cu and $CeO_2$. During pretreatment, the catalyst formed the solid-solution of Cu-Ce-O, resulting in the improvement of catalytic activity.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.64-67
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• 2004

In this paper, to discover the brightness improvement of ZnS:Cu powder electroluminescence (EL), a new structure is proposed in which phosphor and dielectric are mixed between electrodes. Dielectric and phosphor material are BaTiO$_3$ and ZnS:Cu, respectively. The effect of the mixed layer on EL sample is considered the improvement of source efficiency. Although the number of electrons introduced into the phosphor increases only modestly, the high electric field region of phosphor grains increases comparatively in the characteristics of brightness-voltage. Furthermore, the relaxation occurs through leading and trailing edge pairs, which is relatively efficient in characteristics of decay time. With these results, we found that the brightness of newly proposed ZnS:Cu powder electroluminescence was 167.24 cd/$m^2$ at ac voltage of 100V and frequency of 400Hz.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.3
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• pp.47-53
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• 1991

In this study, the structural phase transition and decomposition of superconducting ceramic, Y-Ba-Cu-O system was studied. The results of the study are as follows. The high Tc superconductor $Y_2Ba_2Cu_3O_{7-x}$ is made in solid state reaction of $O_2$ atmosphere and the valve of X in $Y_2Ba_2Cu_3O_{7-x}$ is 0.1~0.2. The transition temperature of tetragonal-orthorhombic phase of $Y_2Ba_2Cu_3O_{7-x}$ appear at $790^{\circ}C-900^{\circ}C$. In the result of measuring the electrical resistance of sample annealed in $O_2$ atmosphere, the electrical resistance show zero at 92 K and the best superconductor, $Y_2Ba_2Cu_3O_{7-x}$(Y 123) can be mabe.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.291-294
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• 2000

The crystallization behavior and dc Conductivities of CuO-P$_2$O$_{5}$ -Nb$_2$O$_{5}$ -V$_2$O$_{5}$ glasses prepared by quenching on the copper plate were investigated. The conductivities of the glasses were range from 10$^{-5}$ s.$cm^{-1}$ / at room temperature, but the conductivities of the glass-ceramics were 10$^{-3}$ s.$cm^{-1}$ / increased by 10$^2$order. The crystalline product in the glass-ceramics was CuV$_2$O$_{6}$ . The linear relationship between in($\sigma$T) and T$^{-1}$ suggested that the electrical conduction in the present glass-ceramics would be due to a small polaron hopping mechanism.

• Nano
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• v.13 no.10
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• pp.1850114.1-1850114.7
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• 2018

Here we report an optimized hot-injection method and a phase transfer strategy for the synthesis of water-soluble $CuInS_2$ QDs with desired properties. The structure and morphology studies demonstrate that the resulting QDs are $CuInS_2$ tetragonal phase with well-defined facets. It is also found that the crystal size gradually increases with the increase of reaction temperature, while the surface of QDs with pre- and post-phase transfer is functionalized with hydrophobic and hydrophilic ligands, respectively. Spectroscopy measurements reveal the size-dependent optical properties of $CuInS_2$ QDs, demonstrating the quantum confinement effect in this system.