• 전기화학회지
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• 제10권4호
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• pp.239-244
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• 2007

산소자리에 치환된 불소가 $Li_{1-x}FeO_2Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8) 양극 활물질에 미치는 영향을 고찰하기 위해 다양한 양의 불소를 치환시킨 $Li_{1-x}FeO_{2-y}F_y-Li_xMnO_2$ (Mn/(Mn + Fe) = 0.8, $0.05{\le}y{\le}0.15$) 양극 활물질을 고상법을 이용하여 합성하였다. 불소 미치환 시료 및 치환양이 0.05와 0.1의 시료의 경우, $1-1.5\;{\mu}m$ 크기의 막대 형상 분말 형태에 50-100 nm정도의 작은 구형 입자들이 주위에 분포되어 있는 형태이었다. 반면, 불소 치환양이 0.15인 시료의 경우, 그 모양이 구형으로 변화되어지며 입자가 급격하게 성장하였다. 합성된 시료를 이용하여 제작된 셀들의 충 방전 수행 결과, $Li/Li_{1-x}FeO_{1.9}F_{0.1}-Li_xMnO_2$ 셀이 163 mAh/g의 가장 높은 초기용량을 보였으며 50 싸이클 후에도 95%의 높은 가역 특성을 보였다. 특히, 활물질내의 불소 치환양이 증가할수록 초기 방전용량도 같이 증가하였으나, 불소이온의 치환양이 일정량을 (y>0.1) 넘는 경우에는 산소 자리에 불소이온이 완전하게 치환되지 못하고 불순물로 존재함으로써 전지의 가역특성을 현저하게 저하시키는 요인으로 작용함을 확인하였다.

• Journal of Magnetics
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• 제11권1호
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• pp.30-35
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• 2006

A thorough study about the influences of Mn substitution for Fe on the microstructure and magnetic characteristics of $Fe_{73.5-x}Mn-{x}Si_{13.5}B_{9}Nb_{3}Cu_1$ (x = 1, 3, 5) alloys prepared by the melt-spinning technique has been performed. Nanocomposites composed of nanoscale $(Fe,Mn)_{3}Si$ magnetic phase embedded in an amorphous matrix were obtained by annealing their amorphous alloys at $535^{\circ}C$ for 1 hour. The addition of Mn causes a slight increase in the mean grain size. The Curie temperatures of the initial amorphous phase and of the nanocrystals phase decreased, while the Curie temperature of the remaining amorphous phase remained nearly constant with increasing Mn content. Soft magnetic properties of the crystallized samples have been significantly improved by a proper thermal treatment. Accordingly, the giant magnetoimpedance effect is observed and ascribed to the increase of the magnetic permeability, and the decrease of the coercivity of the samples. The increased magnetic permeability is resulted from a decrease in the magnetocrystalline anisotropy and saturation magnetostriction.

• 한국분말재료학회지
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• 제17권5호
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• pp.399-403
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• 2010

The effects of $MnO_2$ doping on the crystal structure, ferroelectric, and piezoelectric properties of (K,Na)$NbO_3$ (KNN) ceramics have been investigated. $MnO_2$ was found to be effective in enhancing the densification and grain growth during sintering. X-ray diffraction analysis indicated that Mn ions substituted B-site Nb ions up to 2 mol%, however, further doping induced unwanted secondary phases. In comparison with undoped KNN ceramics, the well developed microstructure and the substitution to B-sites in 2 mol% Mn-doped KNN ceramics resulted in significant improvements in both piezoelectric coupling coefficient and electromechanical quality factor.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2006년도 동계학술연구발표회 및 자성 스핀트로닉스 국제학술대회
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• pp.104-104
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• 2006

• 한국결정성장학회지
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• 제10권5호
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• pp.362-366
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• 2000

$Li_{0.44}MnO_2$양극재료는 리튬의 삽입과정에서 높은 가역성을 가지며 과충전이나 과방전 과정에서 쉽게 손상되지 않는다. $Mn_2O_3$가 불순물로 자주 나타나며 전기화학적으로 비활성이기 때문에 전극의 전기화학적 용량을 감소시킨다. 잉여의 NaOH 첨가는 $Mn_2O_3$를 X선 회절에 검출되지 않는 정도로 낮추었다. 용량 증가는 큰 단위세포를 가지는 양극재료에서 얻어질 수 있으므로, 망간의 일부를 이온반경이 큰 티타니움으로 치환하였으며, $Li_{0.44}T_{iy}Mn_{1-y}O_2$(여기서 y = 0.11, 0.22, 0.33, 0.44, 0.55) 조성의 분말들을 합성하여 특성을 평가하였다. ECPS 실험결과 $Li/P(EO)_8$LiTFSI/$LixTi_{0.22}Mn_{0.78}O_2$전지에서 150 mAh/g 최대가역용량 값이 얻어졌다. 티타니움이 치환된 망간산화물을 사용한 전지는 충방전당 0.12 %나 그 이하의 용량감소율을 나타내었다.

• Transactions on Electrical and Electronic Materials
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• 제4권6호
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• pp.13-16
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• 2003

Mn-doped $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin film phosphors have been grown using a pulsed laser deposition technique under various growth conditions. The structural characterization carr~ed out on a series of $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) films grown on MgO(l00) substrates usmg Zn-rich ceramic targets. Oxygen pressure was varied from 50 to 200 mTorr and Zn/Ga ratio was the function of oxygen pressure. XRD patterns showed that the lattice constants of the $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin film decrease with the substitution of sulfur and selenium for the oxygen in the $ZnGa_2O_4$. Measurements of photoluminescence (PL) properties of $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin films have indicated that MgO(100) is one of the most promised substrates for the growth of high quality $ZnGa_2O_{4-x}M_{x}$:$Mn^{2+}$ (M=S, Se) thin films. In particular, the incorporation of Sulfur or Selenium into $ZnGa_2O_4$ lattice could induce a remarkable increase in the intensity of PL. The increasing of green emission intensity was observed with $ZnGa_2O_{3.925}Se_{0.075}:$Mn^{2+}$ and $ZnGa_2O_{3.925}S_{0.05}$:$Mn^{2+}$ films, whose brightness was increased by a factor of 3.1 and 1.4 in comparison with that of $ZnGa_{2}O_{4}$:$Mn^{2+}$ films, respectively. These phosphors may promise for application to the flat panel displays.

• 한국전기전자재료학회논문지
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• 제20권9호
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• pp.766-770
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• 2007

In this study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator, $0.07Pb(Mn_{1/3}Nb_{2/3})O_3-xPb(Ni_{1/3}Nb_{2/3})O_3-(0.93-x)Pb(Zr,Ti)O_3$ ceramics system were fabricated using $Li_2CO_3-Bi_2O_3-CuO$ sintering aids and the specimens were sintered at $930^{\circ}C$. Thereafter, their piezoelectric and dielectric characteristics were investigated according to the amount of PNN substitution. At 9 mol% PNN substitution, density, electromechanical coupling factor ($k_p$), dielectric constant, mechanical quality factor ($Q_m$) and piezoelectric constant ($d_{33}$) showed the optimum value of $7.86g/cm^3$, 0.60, 1640, 1323 and 387 pC/N, respectively. It is considered that these values are suitable for piezoelectric divece application such ad multilayer piezoelectric actuator and ultrasonic vibrator with pure Ag internal electrode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.344-345
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• 2006

In this study, in order to develop low temperature sintering piezoelectric transformer, $(Pb_{0.99-x}Ca_xSr_{0.01})Ti_{0.96}(Mn_{1/3}Sb_{2/3})_{0.04}O_3$ ceramic systems were fabricated using $Na_2CO_3-Li_2CO_3$ as sintering aids and investigated with the amount of Ca substitution. The piezoelectric transformer requires high electromechanical coupling factor $k_t$ and high mechanical quality factor $Q_{mt}$ for generating high output power At the ($PbCaSr)Ti(MnSb)O_3$ ceramics with 24mol% Ca substitution sintered at $900^{\circ}C$, electromechanical coupling factor $k_t$ and mechanical quality factor $Q_{mt}$ showed the optimal values of 0.504 and 1655 respectively, for thickness vibration mode multilayer piezoelectric transformer application.

• 한국결정학회지
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• 제14권2호
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• pp.110-114
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• 2003

LiAl/sub 0.24/Mn/sub 1.76/O/sub 4-y/S/sub y/ (y=0, 0.02) were synthesized by the sol-gel method. Both structures were refined by Rietveld method, its structure refined as a cubic spinel, space group Fd-3m, a=8.17937(30) Å and 8.18331(19) Å respectively. Though it has been made a charge/discharge experiment above 20 times, there was no change of 3 V/4 V capacity degradation. It was considered that the volume change of MnO/sub 6/ octahedron induced by sulfur substitution plays a key role in keeping the 3 V/4 V capacity. The refined composition of the compound could be confirmed with the ICP analysis.

• 약학회지
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• 제19권2호
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• pp.101-110
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• 1975

p-Chloronitrobenzene(substrate) and p-nitrophenetole (product) were quantitatively analyzed to know the degree of extent of reaction in the process of time. The calibration curve was prepared by the internal satndard method in gaschromatography. 2,6-Dimethyl-naphthalene was used as internal standard. The rate constant(k), the reaction velocity in various concentrations of NaOH altered, and the formation of byproducts(azo-compound and p-nitrophenol) with the amounts of MnO$_{2}$ and NaOH altered, were studied. From the results of these of MnO$_{2}$ and NaOH altered, were studied. From the results of these experiments, this reaction was second order and the rate constant was k=10.3 $\times$ 10$^{-3}$ mole$^{-21$. When p-chloronitrobenaene 1 pt. NaOH 0.56pts. MnO$_{2}$ 0.5pts. and ethanol 25 pts-were reacted about 10 hours, p-nitrophenetole was nearly quantitatively obtained without byproducts.