• Journal of the Korean Chemical Society
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• v.23 no.2
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• pp.59-64
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• 1979

The dipole moments for octahedral $[M(II)Cl_2N_2O_2]$, square planar and tetrahedral $[Pd(II)X_2Y_2]$ type complexes are calculated, using the approximate molecular orbital theory [M(II) = Ni(II) or Co(II), X = N and Y = O or S]. The calculated dipole moments for these complexes are in reasonable agreement with the experimental values. The possible structures for these complexes are investigated on the basis of the calculated dipole moments.

• ETRI Journal
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• v.35 no.6
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• pp.1156-1159
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• 2013

We investigate the characteristics of $Cu_2O$ thin films deposited through the addition of $N_2$ gas. The addition of $N_2$ gas has remarkable effects on the phase changes, resulting in improved electrical and optical properties. An intermediate phase ($6CuO{\cdot}Cu_2O$) appears at a $N_2$ flow rate of 1 sccm, and a $Cu_2O$ (200) phase is then preferentially grown at a higher feeding amount of $N_2$. The optical and electrical properties of $Cu_2O$ thin films are improved with a sufficient $N_2$ flow rate of more than 15 sccm, as confirmed through various analyses. Under this condition, a high bandgap energy of 2.58 eV and a conductivity of $1.5{\times}10^{-2}$ S/cm are obtained. These high-quality $Cu_2O$ thin films are expected to be applied to $Cu_2O$-based heterojunction solar cells and optical functional films.

• Journal of the Korean Magnetics Society
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• v.10 no.4
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• pp.165-170
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• 2000

The purpose of this study is to investigate the effect of annealing conditions on physical and magnetic properties of Fe-Hf-N thin films. When the thin films were annealed in $N_2$ gas, a surface oxide layer, comprised of Fe$_2$O$_3$ and Fe$_3$O$_4$, was formed at the surface of the thin films and a Fe-Hf-O-N layer was also formed under this surface oxide layer. It was found that the thicknesses of the surface oxide layer and the Fe-Hf-O-N layer increased, as the annealing temperature increased. It was also found that if the thickness of the surface oxide layer was excluded in the property calculation, the soft magnetic properties of the annealed thin films were not much different from those of the as-deposited thin films. Therefore, it was suggested that the Fe-Hf-O-N layer formed under the surface oxide layer did not lose significantly the soft magnetic properties of the Fe-Hf-N films and the Fe-Hf-N films annealed in $N_2$gas showed the soft magnetic properties of the Fe-Hf-N and Fe-Hf-O-N multi-layers.

• Journal of the Korean Ceramic Society
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• v.38 no.5
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• pp.424-430
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• 2001

Cut-off 전압 변화에 따른 충방전 특성을 알아보기 위하여 Mn을 다른 전이 금속이 Co와 Ni로 소량 치환시킨 Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$(M=Ni, Co, $\delta$=0, 0.05, 0.1, 0.2)를 고상 반응법으로 80$0^{\circ}C$에서 48시간 동안 유지하여 합성하였다. 충방전의 cut-off 전압은 2.5~4.4V, 3.0~4.5V, 3.5~4.5V, 3.5V~4.7V의 네 가지 전압범위고 하였다. 충방전 실험결과, Li(M $n_{1-{\delta}}$ $n_{\delta}$)$_2$ $O_4$의 용량은 각각 Co와 Ni의 $\delta$=0.1에서 최대를 보였다. Co 치환 조성 재료와 순물질 모두에서 최대의 용량을 보인 cut-off 전압대는 3.5~4.5V 이었는데 이때의 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$와 LiM $n_2$ $O_4$의 초기 충전용량과 초기 방전용량은 각각 118, 119mAh/g과 114, 104mAh/g 이었다. 또한 모든 cut-off 전압대에서 Li(M $n_{0.9}$ $Co_{0.1}$)$_2$ $O_4$는 순수한 LiM $n_2$ $O_4$보다 더 높은 용량과 우수한 싸이클 성능을 보였으며 그 결과는 밀착형 전지구성에서도 일치하였다.하였다.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.113-123
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• 2012

A unit emission reduction of nitrous oxide ($N_2O$) from anthropogenic sources is equivalent to a 310-unit $CO_2$ emission reduction because the $N_2O$ has the global warming potential (GWP) of 310. This greatly promoted very active development and commercialization of catalysts to control $N_2O$ emissions from large-scale stationary sources, representatively nitric acid production plants, and numerous catalytic systems have been proposed for the $N_2O$ reduction to date and here designated to Options A to C with respect to in-duct-application scenarios. Whether or not these Options are suitable for $N_2O$ emissions control in nitric acid industries is primarily determined by positions of them being operated in nitric acid plants, which is mainly due to the difference in gas temperatures, compositions and pressures. The Option A being installed in the $NH_3$ oxidation reactor requires catalysts that have very strong thermal stability and high selectivity, while the Option B technologies are operated between the $NO_2$ absorption column and the gas expander and catalysts with medium thermal stability, good water tolerance and strong hydrothermal stability are applicable for this option. Catalysts for the Option C, that is positioned after the gas expander thereby having the lowest gas temperatures and pressure, should possess high de$N_2O$ performance and excellent water tolerance under such conditions. Consequently, each de$N_2O$ technology has different opportunities in nitric acid production plants and the best solution needs to be chosen considering the process requirements.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.21-21
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• 2014

$CrN/Al_2O_3/CrN$ 다층 코팅을 HIPIMS와 ALD간 하이브리드 코팅법을 통해 형성하였다. ALD를 통해 CrN 층에 도입한 $Al2O_3$층의 두께 및 위치가 $CrN/Al_2O_3/CrN$ 다층 코팅층의 미세구조, 표면 거칠기, 기계적 특성 및 화학적 특성에 미치는 영향에 대해 조사하였다. 전체 공정시간은 거의 변화시키지 않고도, ALD를 이용한 $Al2O_3$층의 삽입에 의하여 기계적/화학적 특성이 크게 개선될 수 있음을 확인하였으며, 개선된 특성에 대한 원인에 대해 조사하였다.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1130-1140
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• 1998

Thin films of $Bi_4Ti_3O_{12}\;nBaTiO_3(n=1&2)$ were prepared using sols erived Ba-Bi-Ti complex alkoxides. The sols were spin-cast onto $Pt/Ti/SiO_2/Si$ substrates and followed by pyrolysis for 1 hr at $620^{\circ}C,\;700^{\circ}C\;and\;750^{\circ}C$ In the thin films a pyrochlore phase seemed to be formed at a lower temperature and then tran-formed to the layered perovskite phase as the heating temperature increased. In the thin films pyrolyzed at formed to the layered perovskte phase as the heating temperature increased. In the films pyrolyzed at $750^{\circ}C$ the amount of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ reached to 94% while $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ was 77% in composition. This result shows that the formation of the layered pervoskite phase becomes difficult as the amount of complexing $BaTiO_3$ increases. The microstructures and the electrical properties of the thin films were gen-erally improved with the incease of the heating temperature. However the presence of the pyrochlore phase could not be removed effectively. Our study showed that the electrical properties of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ were pronouncedly improved with complexing with BaTiO3 when compared to those of $Bi_4Ti_3O_{12}$ while the presence of the pyrochlore phase was detrimental to the those of $Bi_4Ti_3O_{12}{\cdot}2BaTiO_3$.

• Journal of the Korean Ceramic Society
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• v.37 no.1
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• pp.1-5
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• 2000

Cathodoluminescence(CL) properties of ZnO:Zn green phosphor were investigated. ZnO:Zn phosphor was synthesized by varying reducing agents and firing temperatures. ZnS, charcoal and 5% H2 gas mixed with 95% N2 gas(5H2-95N2) were used as the reducing agent and atmosphere. The highest CL intensity of ZnO:Zn phosphor was observed under the condition of 5H2-95N2 atmosphere and firing temperature of 90$0^{\circ}C$ for 1h. Charocal and ZnO as reducing agents in the syntehsis of ZnO:Zn phosphor exhibited about 60% and 40%, respectively, of the CL intensity obtained with 5H2-95N2 atmosphere.

• Membrane Journal
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• v.30 no.5
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• pp.319-325
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• 2020

In this study, we developed mixed matrix membranes by blending thermoplastic elastomer, i.e. polystyreneblock-polybutadiene-block-polystyrene (SBS) block copolymer with the synthesized UiO-66 particles for CO₂/N₂ gas separation. To investigate the effect of UiO-66 particles in the SBS matrix, we prepared different mixed matrix membranes (MMMs) by varying the mass ratio of SBS and UiO-66 in the blend. To fabricate well-dispersed UiO-66, the SBS/UiO-66 mixture was sonicated and stirred thoroughly. The physico-chemical properties of prepared membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The gas separation performance was measured by time-lag method. The permeability of the MMMs increased significantly as the content of UiO-66 increased, but the CO₂/N₂ selectivity did not decrease significantly. The membranes containing 20% of UiO-66 particles showed the best performance with the CO₂ permeability and CO₂/N₂ selectivity of 663.8 barrer and 13.3, respectively. This result showed performance closer to upper bound than pure SBS membrane in the Robeson plot, as the added UiO-66 particles did not significantly sacrifice selectivity and more than doubled gas permeability.

• Korean Journal of Materials Research
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• v.9 no.9
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• pp.932-936
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• 1999

4NH(sub)3+$3O_2$$\longrightarrow$$2N_2$+$6H_2$O 의 화학반응식을 가지며$ O_2$ 및 $H_2$O를 산화제로 하는 $NH_3$/$O_2$산화의 성장모델을 세웠으며, 그 결과 Fick의 제 1 법칙을 기초로 하는 건식 및 습식 산화메카니즘으로 이해되는 Deal-Grove의 산화막 성장모델과 유사한 결과가 도출되었다. 이 성장모델에 의하면 산화제$ O_2$ 및 $H_2$O가 상호보완적으로 산화에 영향을 미치므로 산화온도 뿐 아니라 $NH_3$/O$_2$의 유량비도 산화율을 결정한다. rapid thermal processing(RTP)에 의한 산화막 성장실험으로 본 연구에서 제안하는 성장모델을 확인하였으며, NH$_3$분자의 분해에 의해 발생하는 N 원자의 산화막 내부확산을 secondary ion mass spectroscopy(SIMS)로 확인하였으며, Auger electron spectroscopy (AES) 측정결과 N 원자의 존재는 무시할만한 수준이었다.