• 한국재료학회지
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• 제14권12호
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• pp.889-892
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• 2004

The synthesis of $Zn_{2}SiO_4:Mn^{2+}$ for PDP green phosphor by SHS(Self-propagating High temperature Synthesis method) was studied. The precursors were well mixed and cold compacted. And then, the green pellet was synthesized at high temperature through self-propagating high temperature zone. Because this reaction uses the heat resulted from the oxidation of Zn metal powder in this system, Zn/ZnO mole ratio is one of the most important reaction variable. Throughout several experiments, the optimal condition of Zn/ZnO mole ratio and Mn concentration are 1.2/0.8 and 0.05mo1e, respectively.

• 한국세라믹학회지
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• 제35권10호
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• pp.1101-1106
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• 1998

Various $Zn_{2-x}SiO_4$:xMn based green phosphors were investigated in association with a co-dopant. The co-dopant incorporated into the phosphors are believed to alter the internal energy state of $Zn_{2-x}SiO_4$ : xMn So that the improvement in their intensity could be expected. Phosphor samples were prepared using the solid state reaction therein raw powders are mixed in the acetone and successively fired at $1300^{\circ}C$ for 4 hour. The fired powders are also heated up to $900^{\circ}C$ for 2 hour in the reduced atmoshpere and thereby giving The fired powders are also heated up to $900^{\circ}C$ for 2 hour in the reduced atmosphere and thereby giving rise to conspicuous enhancement of radiative efficiency. Basically the 0.08 mole ratio of the Mn con-centrations has the maximum value of the intensity so that a co-dopant are added to this Mn con-centration. When the Mg is co-doped with Mn luminescent intensity is proven to be promoted significantly.

• 한국자기학회지
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• 제17권1호
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• pp.22-25
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• 2007

본 연구에서는 하지층으로 Mo을 사용한 스핀밸브구조에서 반강자성체 IrMn의 두께 변화에 따른 자기적 특성을 연구하였다. 사용된 스핀밸브는 Si기판/$SiO_2/Mo(17\;{\AA})NiFe(21\;{\AA})/CoFe(28\;{\AA})/Cu(22\;{\AA})/CoFe(18\;{\AA})/IrMn(t\;{\AA})/Ta(25\;{\AA})$ 구조이다. Mo 박막의 비저항은 $600^{\circ}C$에서 $650^{\circ}C$ 열처리 후 급격히 증가하였다. 반강자성체인 IrMn의 두께 변화(130 ${\AA}$까지)에 따른 자기저항비와 교환결합력을 측정하였다. IrMn의 두께가 65 ${\AA}$ 일때 자기저항비와 교환결합력은 9.65%와 337.5 Oe로 최고값을 나타냈다. 그러나 두께를 더욱 증가시킨 97.5 ${\AA}$ 일때 자기저항비와 교환결합력은 8.2%와 285 Oe로 감소하였으며, IrMn의 두께가 130 ${\AA}$ 일때 자기저항비와 교환결합력은 더욱 감소한 7.65%와 257.5 Oe이었다.

• 한국세라믹학회지
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• 제40권7호
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• pp.637-643
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• 2003

PDP(Plasma Display Panel)용 녹색 형광체의 발광특성과 결정성을 향상시키기 위해 Zn$_2$SiO$_4$:Mn에 co-dopant로 Cr과 Ti 를 각각 첨가하여 졸-겔법으로 합성하였다. 이렇게 합성된 Zn$_2$SiO$_4$:Mn, M(M=Cr, Ti) 형광체는 고상반응의 경우와 비교하여 상대적으로 낮은 온도인 110$0^{\circ}C$에서 willemite 구조의 단일상이 형성되었다. 제조된 Zn$_2$SiO$_4$:Mn, M(M=Cr, Ti) 형광체에 대하여 진공자외선(Vacuum Ultraviolet, VUV) 영역의 147 nm 여기광원을 사용하여 발광특성을 조사하였다. Co-dopant의 영향을 알아보기 위해 Mn의 농도는 2 ㏖%, $H_2O$/TEOS의 비율은 36.1로 고정하였고, 이때 Cr과 Ti 모두 0.1 ㏖%에서 가장 좋은 발광특성을 나타냈다. Cr이 co-doping된 경우는 농도가 증가할수록 잔광시간은 짧아지나 발광강도는 지속적으로 감소한 반면, Ti를 co-doping했을 때는 오히려 낮은 농도에서 발광강도의 증가를 보이며 2.0 ㏖%에서 급격히 감소하였다.

• 공업화학
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• 제31권1호
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• pp.57-60
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• 2020

An acetaldehyde, a representative food waste odor, was decomposed using a hybrid system comprised of a non-thermal plasma and catalyst at an ambient temperature under high humidity. A five wt.% Mn was impregnated on two differently structured microporous zeolites, namely Beta and ZSM-5, with a different molar ratio of SiO₂/Al₂O₃. Under high humidity conditions, the acetaldehyde degradation was higher in zeolites with the high ratio of SiO₂/Al₂O₃. Among studied catalysts, a five wt.% Mn/Beta (SiO₂/Al₂O₃ = 300) showed the highest acetaldehyde removal activity owing to its high hydrophobicity and reducibility. During long term stability test using the same catalyst for 110 hours, the acetaldehyde removal activity was relatively well-maintained.

• 한국진공학회지
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• 제20권3호
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• pp.205-210
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• 2011

졸-겔(sol-gel) 방법을 이용하여 스피넬(spinel) 구조의 산화물 $LiMn_2O_4$ 박막을 Pt/Ti/$SiO_2$/Si 기판 위에 제작하여 그 구조적 성질 및 이차 전지 전기화학적 특성을 조사하였다. 박막에서의 Li/Mn 몰비(molar ratio)가 0.5 미만일 경우 박막에 $LiMn_2O_4$ 상뿐만 아니라 $Mn_2O_3$ 상이 존재함이 관측되었다. $LiMn_2O_4$ 박막을 이용한 반전극(half cell) 전지를 제작하여 충전-방전 순환과정을 반복수행 하였고, 과정 시작 전후에 X-ray diffraction 및 Raman spectroscopy 측정을 통하여 과정 중 발생하는 박막의 구조적 성질 변화를 조사하였다. 순수한 $LiMn_2O_4$ 박막 전지의 경우 충전-방전 횟수가 증가함에 따라 방전 용량은 서서히 감소하여 300회에 이르러서는 초기 용량의 72%로 줄어들었다. 이와 같은 결과는 충전-방전 과정 중 스피넬 구조의 사면체 자리로부터 탈리되었다가 다시 삽입되는 $Li^+$ 이온 수의 감소 및 이에 따르는 $Mn^{4+}$ 이온 수 증가와 관련이 있는 것으로 해석된다. 또한, 순환 횟수가 증가함에 따라 박막 내에 $Mn_2O_3$ 상의 밀도가 점차 증가함이 관측되었다.

• Corrosion Science and Technology
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• 제9권6호
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• pp.247-253
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• 2010

The characteristics of selective oxidation prior to hot-dip galvanizing with the annealing atmosphere dew point and chemical composition in dual-phase steels and their effect on the inhibition layer formation relevant to coating adhesion have been studied using a combination of electron microscopic and surface analytical techniques. The annealed and also galvanized samples of 3 kinds of Si/Mn ratios with varied amounts of Si addition were prepared by galvanizing simulator. The dew point was controlled at soaking temperature $800^{\circ}C$ in 15%$H_2$ -85%$N_2$ atmosphere. It was shown that good adhesion factors were mainly uniformity of oxide particle distribution of low number density and low Si/Mn ratio prior to hot-dip galvanizing. Their effect was the greatly reduced coating bare spots and the formation of uniform inhibition layer leading to good adhesion of Zn overlay. The mechanism of good adhesion is suggested by two processes: the formation of inhibition layer on the oxide free surface uncovered with no $SiO_2$-containing particles in particular, and the inhibition layer bridging of oxide particles. The growth of inhibition layer was enhanced markedly by the delayed reaction of Fe and Al with the increase of Si/Mn ratio.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.840-844
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• 2003

The main objective of this investigation is to improve the photoluminescent of $Zn_{2}SiO_{4}:Mn$ phosphors prepared by the sol-gel technique. We try to use adding a new co-dopan such as Cr and Ti. The calcination temperature of sol-gel technique(1100 $^{\circ}C$) was lower than that of the solid state reaction (1300 $^{\circ}C$). Under 147nm excitation, the maximum emission intensity was obtained when the concentration of Cr and Ti was 0.1mol% with respect to $Zn_{2}SiO_{4}:Mn$. In order to study the effect of co-dopant, the content of Mn and the ratio of water to TEOS were fixed at 2mol% and 36:1, respectively.

• 한국세라믹학회지
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• 제37권7호
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• pp.665-672
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• 2000

The ferroelectric YMnO3 thin films were prepared by MOD(metal-organic decomposition) method with Y- and Mn-acetylacetonate as starting materials. Thin films were grown on various substrates by spin-coating technique. The crystalline phases of the thin films were identified by X-ray diffractometer as a function of heat-treatment temperature, pH of coating solution and substrate. In addition, the effect of Mn/Y molar ratio(0.8~1.2) on the formation of hexagonal-YMnO3 phase was investigated. In forming highly c-axisoriented hexagonal-YMnO3 single phase, the Pt coated Si substrate was more effective than the bare Si substrate, and the optimum heat-treatment condition was at 82$0^{\circ}C$ for 30 min. Higher Mn/Y molar ratio within 0.8~1.2 and pH of YMnO3 precursor solution within 0.5~2.5 favored formation of ferroelectric hexagonal phase rather than orthorhombic phase. Leakage current density of the hexagonal-YMnO3 thin film formed on Pt(111)/TiO2/SiO2/Si substrate was low enough as 0.4~4.0$\times$10-8(A/$\textrm{cm}^2$) at 5 V and its remanent polarization(Pr), calculated from the P-E hysteresis loop, was 3 nC/$\textrm{cm}^2$.

• 소성∙가공
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• 제4권2호
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• pp.151-158
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• 1995

In this study, the width spreads of spring steel including Mn-Cr steel(SUP 9A), Mn-Cr-V steel(SUP 11A), and Si-Cr steel(SAE 9254) and were investigated under different reduction ratios and thickness-width ratios friction coefficients. The experimental results were compared with the theoretical prediction by the Ekelund equation, Geuze equations, etc. The width spreads of the three spring steels were found to be 10-15% larger than mild steel, and the optimal reduction ratio for the spring steel was found in a range from 20 to30%. Among the spring steels, the width spread of Mn-Cr-V steel was measured to be the largest followed by those of Si-Cr steel and Mn-Cr steel. It was found that the width spread increased with friction coefficient, width-thickness ratio and reduction ratio as predicted. However, the theoretical predictions revealed smaller width spread than the experimental results. This finding indicates that the coefficients of the width spread of the theoretical models need to be modified in order to predict the actual behavior of the width spreading of the spring steels. In this study, the coefficients of width spread of the Geuze equation were determined from the experimental results.