• 한국세라믹학회지
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• 제37권7호
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• pp.651-651
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• 2000

• 전기전자학회논문지
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• 제23권4호
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• pp.1175-1181
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• 2019

논문에서는 1:10으로 희석된 실리카 슬러리에 산화망간(MnO₂) 연마제를 첨가하여 재처리된 혼합연마제 슬러리(Mixed Abrasive Slurry; MAS)의 화학기계적연마(CMP) 특성을 연구하였다. 최적의 연마 성능을 갖는 슬러리를 설계하기 위해서는 높은 연마율, 하부층에 대한 적절한 연마선택비, 연마 후의 낮은 표면결함, 슬러리의 안정성 등을 얻어야 한다. 산화망간이 첨가된 MAS의 연마 성능은 연마율 및 비균일도와 같은 CMP 성능, 입도 분석, 표면 형상에 대해 평가하였다. 실험결과, 높은 연마율과 낮은 비균일도 측면에서 볼 때 원액 실리카 슬러리와 대등한 슬러리 특성을 얻을 수 있었다. 따라서 본 연구에서 제안하는 MnO₂-MAS를 사용하면 고가의 소모재인 슬러리를 절약하는데 매우 유용할 것이다.

• 소성∙가공
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• 제17권4호
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• pp.240-248
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• 2008

The effect of alloying elements(Mn, S, Mo, B) on the high temperature deformation behavior of Fe-29%Ni-17%Co (Kovar) alloy were investigated. And the effect of high temperature oxidation on the hot ductility was also studied. The hot ductility of Kovar alloy was drastically increased with the addition of Mn and lowering of S content. It has been found that the brittle intergranular fracture at high temperature cracking is closely associated with the FeS sulfide along the grain boundary. When Mn was added, the type of sulfide was changed to MnS from FeS and ductile intergranular fracture and transgranular fracture were promoted. The formation of oxide layer was found to have minimized the hot ductility of the Kovar alloy significantly. Grain boundary micro-cracks in the internal oxide region were noted following deformation due to high temperature, one of which acting as a notch that caused the poor hot workability of the oxidized specimen. The addition of Mo to the Kovar alloy could also retard the decrease in the hot ductility of the oxidized specimen through the prevention of notching due to internal oxidation. Hot ductility was remarkably improved by the addition of Boron. The improvement of hot ductility results from the grain boundary migration mainly due to the dynamic recrystallization at lower temperature range ($900{\sim}1000^{\circ}C$).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.409-409
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• 2011

All solid-state thin film lithium batteries have many applications in miniaturized devices because of lightweight, long-life, low self-discharge and high energy density. The research of cathode materials for thin film lithium batteries that provide high energy density at fast discharge rates is important to meet the demands for high-power applications. Among cathode materials, lithium manganese oxide materials as spinel-based compounds have been reported to possess specific advantages of high electrochemical potential, high abundant, low cost, and low toxicity. However, the lithium manganese oxide has problem of capacity fade which caused by dissolution of Mn ions during intercalation reaction and phase instability. For this problem, many studies on effect of various transition metals have been reported. In the preliminary study, the Sn-substituted LiMn2O4 thin films prepared by pulsed laser deposition have shown the improvement in discharge capacity and cycleability. In this study, the thin films of LiMn2O4 and LiSn0.0125Mn1.975O4 prepared by RF magnetron sputtering were studied with effect of deposition parameters on the phase, surface morphology and electrochemical property. And, all solid-state thin film batteries comprised of a lithium anode, lithium phosphorus oxy-nitride (LiPON) solid electrolyte and LiMn2O4-based cathode were fabricated, and the electrochemical property was investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.148-151
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• 2003

The spin density of ${\beta}-MnO_2$ structure was theoretically investigated by $DV-X_{\alpha}$ (the discrete variation $X{\alpha}$) method, which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The used cluster model was $[Mn_{14}O_{56}]^{-52}$. The ${\beta}-MnO_2$ is a paramagnetic oxide semiconductor material having the energy band gap of 0.18 eV and an 3 loan-pair electrons in the 3d orbital of an cation. This material exhibits spin-only magnetism and has the magnetic ordering temperature of 94 K. Below this temperature its magnetism appears as antiferromagnetism. The calculations of electronic state showed that if the initial spin condition of input parameters changed, the magnetic state changed from paramagnetic to antiferromagnetic. When d orbital of all Mn atoms in cluster had same initial spin state as only up spin, paramagnetic spin density distribution appeared by the calculation. On the other way, d orbital had alternately changed spin state along special direction the resulted spin distribution showed antiferromagnetism.

• 공업화학
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• 제7권1호
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• pp.9-17
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• 1996

고체전해질형 연료전지용 전해질로 사용되는 8mol% YSZ($Y_2O_3$ stabilized zirconia)의 소결조건을 변화시켜 이온전도도를 측정하였다. 그 결과 소결조건이 $1400^{\circ}C$, 10시간이었을 때 가장 높은 값인 $10^{-1}S.cm^{-1}$를 나타내었다. 또한 산소극재료로서 $La_{1-x}Sr_xMnO_3$($0{\leq}{\times}{\leq}1$)를 고상반응법으로 제조하여 과전압, 전자 전도도, 전해질인 YSZ와의 계면저항등을 살펴보았다. 그 결과 La에 대한 Sr의 치환량이 50mol%일 때 가장 우수한 특성을 나타내었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.196.2-196.2
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• 2014

Nanostructuring the electrode surface is an emerging technology to improve the performance of supercapacitors since it can facilitate charge transfer, ion diffusion and electron propagation during electrochemical process. Fabrication of the electrode consisting of two or more materials together has also been focused on since it can provide synergetic effect such as broader working potential range and enhanced capacitance. In this work, we have used polyaniline (PANi) and manganese oxide (MnO2) as electrode materials. PANi is one of the promising electrode materials due to its high electrochemical activity, high doping level and stability. MnO2 is also widely studied material for supercapacitors since it is relatively cheap and environmentally friendly. Firstly, we synthesized polystyrene nanospheres on MnO2 nanoparticles. MnO2-incorporated PANi hollow nanospheres were then fabricated by polymerizing aniline monomers on these PS nanospheres and dissolving the inner PS spheres. The surface morphology, electronic absorption and electrical conductivity of the electrode were analyzed using field-emission scanning electron microscope (FE-SEM), UV-visible spectrometer, and sheet resistivity meter, respectively. The electrochemical properties such as capacitance of the supercapacitors were also estimated using cyclic voltammetry.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.82-82
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• 2008

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2761-2764
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• 2011

A new Ruddlesden-Popper phase $NdSr_2MnCrO_7$ has been prepared by the standard ceramic method. The powder X-ray diffraction studies suggest that the phase crystallizes with tetragonal unit cell in the space group I4/mmm. The electrical transport properties show that the phase is an electrical insulator and the electrical conduction in the phase occurs by a 3D variable range hopping mechanism. The magnetic studies suggest that the ferromagnetic interactions are dominant.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2889-2890
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• 2014