• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.444-447
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• 2000

The spinel L $i_{1-x}$ M $n_2$ $O_4$has been synthesized by the solid-state reaction. L $i_{l-x}$M $n_2$ $O_4$which includes a mixture of LiOH . $H_2O$ and Mn $O_2$prepared by preliminary heating at 35$0^{\circ}C$ for 12hr. L $i_{l-x}$M $n_2$ $O_4$fired at temperature range from 75$0^{\circ}C$ for 48hr. The structure and the electrochemical characteristics of spinel to L $i_{1-x}$ M $n_2$ $O_4$which is fabricated by changing sintering condition from starting materials are investigated. The cyclic voltammetric measurement was performed using 3 electrode cells. Electrode specific capacity and cycle life behavior were tested in a 3.0~4.2V range at a constant current density of 0.45mA/c $m^2$. To improve the cycle performance of spinel L $i_{l-x}$M $n_2$ $O_4$as the cathode of 4V class lithium secondary batteries, spinel phases L $i_{1-x}$ M $n_2$ $O_4$were Prepared at various lithium. The results showed that discharge capacity of L $i_{l-x}$M $n_2$ $O_4$varied at lithium quantity decrease with increasing lithium add quantity. The discharge capacities of L $i_{0.925}$M $n_2$ $O_4$and LiM $n_2$ $O_4$revealed 108 and 117mAh/g, respectively.spectively.y.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.126-129
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• 2001

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.126-129
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• 2001

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process ws performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.386-396
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• 2018

Cropland is sources of atmospheric nitrous oxide ($N_2O$) and carbon dioxide ($CO_2$). However, the contribution of the fallow season to emission of these gases has rarely been determined. In this study, a field experiment encompassing three treatments was conducted to determine efflux of $N_2O$ and $CO_2$ in cropland during fallow season. The treatments were hairy vetch (H.V.), rye and control (Con.). The H.V. and rye were sown in middle October and early November, respectively. The soil $N_2O$ efflux among all three treatments in the fallow season (November-April) were $0.014-2.956mg\;N_2O\;m^{-2}{\cdot}d^{-1}$. The cumulative $N_2O$ emissions were $104.4mg\;N_2O\;m^{-2}$ for Con., $85.8mg\;N_2O\;m^{-2}$ for H.V. and $85.0mg\;N_2O\;m^{-2}$ for Rye during the fallow season. The highest $N_2O$ emissions occurred in Con., while H.V. and Rye emissions were similar. Cumulative $CO_2$ emissions were $293.1g\;CO_2\;m^{-2}$ for Con., $242.2g\;CO_2\;m^{-2}$ for H.V., $275.2g\;CO_2\;m^{-2}$ for Rye during fallow season. This study showed that soil $N_2O$ and $CO_2$ average daily emission during fallow season were 28.3% and 27.4%, respectively of the growing season. Our results indicate that $CO_2$ and $N_2O$ emissions from agricultural systems continue throughout the fallow season.

• Journal of the Korean Applied Science and Technology
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• v.38 no.2
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• pp.356-367
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• 2021

This study investigated the effect of swimming exercise on inflammation in non-alcoholic fatty liver using animal models of postmenopausal obese women. Experimental animals were divided into a sham-operate + non-swimming trained group (S/N), an ovariectomize + non-swimming trained group (O/N) and an ovariectomize + swimming trained group (O/S), and were bred while eating a high fat diet for 8 weeks. Fat accumulation in liver tissue, liver weight, and serum AST and ALT increased in O/N compared to S/N, but decreased in O/S compared to O/N. Compared to S/N, O/N decreased the gene expression of IκBα in liver tissue and increased gene expression of MCP-1, IL-6, and TNF-α. But compared to O/N, O/S increased the gene expression of IκBα in liver tissue and decreased gene expression of MCP-1, IL-6, and TNF-α. In conclusion, this study suggested that swimming exercise was effective in improving physical health by improving inflammation in non-alcoholic fatty liver in obese mice induced obesity by high fat diet after ovariectomy.

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1158-1161
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• 1997

The potentiometric methods have been used to determined the protonation constants (logKiH) for the synthesized 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N''-tri(methylacetic acid) [N3O3-tri(methylacetic acid)] and the stability constants (logKML) of the complexes of divalent and trivalent metal ions with the ligand N3O3-tri(methylacetic acid). The protonation constants of N3O3-tri(methylacetic acid) were 9.70 for logK1H, 9.18 for logK2H, 7.27 for logK3H, 3.38 for logK4H, and 2.94 for logK5H. The stability constants for the complexes of divalent metal ions with N3O3-tri(methylacetic acid) were 10.39 for Co2+, 10.68 for Ni2+, 13.45 for Cu2+, and 13.00 for Zn2+. The order of the stability constants for the complexes of the divalent metal ions with N3O3-tri(methylacetic acid) was Co2+ < Ni2+ < Zn2+ < Cu2+. The stability constants for the complexes of trivalent metal ions with N3O3-tri(methylacetic acid) were 16.20 for Ce3+, 16.40 for Eu3+, 16.27 for Gd3+, and 15.80 for Yb3+. The results obtained in this study were compared to those obtained for similar ligands, 1,7-dioxa-4,10,13-triazacyclopentadecane-N,N',N"-tri(methylacetic acid) and 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N"-triacetic acid, which have been previously reported.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.192-193
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• 2009

CrN 코팅막은 고온에서 치밀한 Cr2O3 확산방지막을 형성함으로 $800^{\circ}C$까지 기계적성질을 유지할 수 있다. 본 실험에서는 Ar, N2, 그리고 $O_2$ 가스 분위기에서 AIP(Arc Ion Plating) 기법에 의해 다양한 조성의 Cr-O-N 박막을 Si(200)과 AISI 304 기판 위에 증착되었다. Cr-O-N 코팅막은 47.4at% 미만의 산소함량을 포함 할 때까지 B1구조를 유지하였고 코팅막 내 산소함량 24.6at%에서는 강한 XRD peak intensification을 나타내었다. 47.4at%에서는 결정상을 전혀 찾아볼 수 없는 전이구조를 나타내었고, 그 이상의 산소함량에서는 Cr22O3 결정상을 나타내었다. Cr-O(17at%)-N 조성의 코팅막에서는 (200)배향의 Grain 크기 증가 및 압축잔류응력이 증가하였으나, 그 이상의 산소함량에서는 점차 감소하였다. Cr-O(24.6at%)-N 조성의 코팅막이 가장 높은 경도를 나타내었고, 산소함량이 증가할수록 점차 향상된 마찰특성을 보였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.148-149
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• 2006

Capacitance-voltage(C-V) 측정평가를 통하여 ZnO/GaN 이종접합구조의 전기적인 특성을 조사한다. 실온에서 10kHz의 주파수에서 얻은 ZnO/GaN의 이종접합구조에 대한 C-V 측정결과는 이종접합계면에서 고밀도의 전자가 축적되어 있음을 나타낸다. 이것은 ZnO/GaN 이종접합계면의 다른 재료에서 볼 수 없는 큰 전도대불연속에 기인한 것인데, 각각의 층의 전도도을 제어함으로 이종접합계면에 축적되는 전자밀도를 ${\sim}10^{19}cm^{-3}$까지 증가시킬 수 있다. 따라서 ZnO/GaN 이종접합구조는 이종접합(合)트래지스터로서 유망한 재료로 판단된다.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.635-641
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• 2021

Cr thin films with O added are deposited on sapphire substrate by DC sputtering and are nitrided in NH₃ atmosphere between 300 and 900 ℃ for various times. X-ray diffraction results show that nitridation begins at 500 ℃, forming CrN and Cr₂N. Cr oxides of Cr₂O₃ are formed at 600 ℃. And, at temperatures higher than 900 ℃, the intermediate materials of Cr₂N and Cr₂O₃ disappear and CrN is dominant. The atomic concentration ratios of Cr and O are 77% and 23%, respectively, over the entire thickness of as-deposited Cr thin film. In the sample nitrided at 600 ℃, a CrN layer in which O is substituted with N is formed from the surface to 90 nm, and the concentrations of Cr and N in the layer are 60% and 40%, respectively. For this reason, CrN and Cr₂N are distributed in the CrN region, where O is substituted with N by nitridation, and Cr oxynitrides are formed in the region below this. The nitridation process is controlled by inter-diffusion of O and N and the parabolic growth law, with activation energy of 0.69 eV.

• Korean Journal of Materials Research
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• v.12 no.4
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• pp.304-307
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• 2002

A zinc oxide (ZnO) single crystal was used as a substrate in the hydride vapor-phase epitaxy (HVPE) growth of GaN and the structural and optical properties of GaN layer were characterized by x- ray diffraction, transmission electron microscopy, secondary ion mass spectrometry, and photoluminescence (PL) analysis. Despite a good lattice match and an identical structure, ZnO is not an appropriate substrate for application of HVPE growth of GaN. Thick film could not be grown. The substrate reacted with process gases and Ga, being unstable at high temperatures. The crystallinity of ZnO substrate deteriorated seriously with growth time, and a thin alloy layer formed at the growth interface due to the reaction between ZnO and GaN. The PL from a GaN layer demonstrated the impurity contamination during growth possibly due to the out-diffusion from the substrate.