• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.5-8
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• 1994

In this paper, Dielectric and strain properties of (1-x-y)PMN-yPT-xST Ceramics hale been investigated as a function of the amount of SrTiO$_3$(ST). The SrTiO$_3$ content is ranged from 0.01-0.05(wt%). As the amount of ST is increased, dielectric constant has a maximun value at 0.05 mol% composition. The Curie temperature is decreased linearly with increasing ST composition and Polarization properties have been investigated. Coercive field and remnant polarization has a maximum value at 0.01mo1% composiion.

• 한국결정성장학회지
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• 제20권2호
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• pp.74-79
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• 2010

The synthesis and reactivities of molybdenum carbide crystallites were examined in this study. Especially, the effect of synthesis conditions were scrutinized on the preparation of molybdenum carbide crystallites. In order to perform this purpose, various characterization techniques such as BET surface area and oxygen uptake measurements were employed for the synthesized molybdenum carbide crystallites. First of all, the molybdenum carbide crystallites were synthesized using molybdenum oxide crystallites and methane gas or methane-hydrogen mixture. The experimental results showed that BET surface areas ranged from $7.4m^2/g$ to $31m^2/g$ and oxygen uptake values varied from $8.1{\mu}mol/g$ to $24.3{\mu}mol/g$. The Mo compounds were found to be active for ammonia decomposition reaction. Even though there are some molybdenum carbide crystallites that were exceeded by Pt/$Al_2O_3$ crystallite, the steady state reactivities for other molybdenum carbide crystallites were comparable to or even higher than that determined for the Pt/$Al_2O_3$ crystallite. These results implied that molybdenum carbide crystallites could be one of the promising crystallites that might be substitutes for Pt-like noble metal crystallites in the petroleum processes.

• 한국재료학회지
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• 제4권6호
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• pp.669-680
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• 1994

합금원소(Cr, V, Si. Mo, Nb)가 첨가된 TiAi 금속간화합물의 고온 산화거동을 대기중의 900~$1100^{\circ}C$에서 관찰하였다. 산화반응물은 XRD, SEM, WDX을 이용하여 분석하였다. 등온 산화에 있어서 Cr과 V이 각각 첨가된 시편은 무게증가가 많았으나, Si, Mo, Vb가 각각 첨가된 시편은 상대적으로 무게증가각 적었아. 그리고, Cr과 V이 각각 첨가된 시편의 산화속도는 TiAi의 그것보다 항상 크게 나타났으며, Si, Mo, Vb가 각각 첨가된 시편의 산화속도는 TiAi의 그것보다 향상되지 않고, Si, Mo또는 Nb 첨가는 내산화성을 향상시킨다. Si, Mo, Nb이 각각 첨가된 TiAI합금표면에 형성된 산화물은 보호막 역할을 함으로 산소와 합금원소의 확산을 감소시키는 역할을 하였다. 특히, Nb는 산화의 초기단계에서는 $AI_{2}O_{3}$를 형성하려는 경향이 강하기 때문에 연속적인 $AI_{2}O_{3}$층과 조밀한 $Tio_{2}+AI_{2}O_{3}$ 혼합층이 형성되었다. Nb가 첨가된 합금의 백금 marker 실험결과에 따르면, 산소가 주로 합금내부로 확산하여 합금표면에서 산화물을 형성하였다. $900^{\circ}C$에서의 열반복주기(thermal cyclic)산화실험 결과, 다른 합금원소와 비교해 볼 때 Cr또는 Nb첨가가 금속기지와 산화층간의 접착력을 향상시키는 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.295-299
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• 1999

The (S $r_{1-x}$C $a_{x}$)Ti $O_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/ $SiO_2$/ Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mo1%]. The dielectric constant changes almost linearly in temperature ranges of -80~ +90[$^{\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200(kHz).)..

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.451-454
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• 2006

WGS reaction over Mo2C and ceria based catalysts was investigated to develop an alternative commercial Cu-Zn/Al2O3 catalyst for fuel processor and hydrogen station. The Mo2C catalysts were prepared by a temperature programmed method and the various metal supported cerium oxide catalysts were prepared by an Impregnation method. The catalysts were characterized by the N2 physisorption, Co chemisorption, XRD, TEM and TPR. It was found that Mo2C and 0.2wt% Pt-40wt%, Ni/CeO2 catalysts had higher activity and stability than the Cu-Zn/Al203 above $260^{\circ}C$. Moreover, CO conversion of more than 85% was observed at $280{\sim}300^{\circ}C$. But all catalysts were deactivated during the thermal cycling runs. The results suggest that these catalysts are an attractive candidate for the alternative Cu-Zn/Al2O3 catalyst for fuel processor and hydrogen station applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.550-553
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• 2001

$Li_{2}O-P_{2}O_{5}-Bi_{2}O_{3}-V_{2}O_{5}$ glass containing glass former, $P_{2}O_{5}$ and $Bi_{2}O_{3}$ was prepard by melting the glass batch in pt. erucible followed by guenching on the copper plate. We found that $Li_{2}O-P_{2}O_{5}-Bi_{2}O_{3}-V_{2}O_{5}$ glass-ceramics obtained from the crystallization of glass showed signifieantly higher capacity and longer cycle life tham $LiV_{3}O_{8}$ made from powder synthesis. In this paper, we described crystallization process and $LiV_{3}O_{8}$ crystal growth in glass matrix by increasing temperature. The electrochemical properties were strongly affected by $LiV_{3}O_{8}$ crystal growth in matrix

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.797-800
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• 2002

Instead of a solution process producing amorphous $LiV_3O_8$ form, we prepared Lithium vanadate glass by melting $Li_2O-P_2O_5-V_2O_5$ and $Li_2O-P_2O_5-Bi_2O_3-V_2O_5$ composition in pt. crucible and by quenching on the copper plate. From the crystallization of $Li_2O-P_2O_5-V_2O_5$ and $Li_2O-P_2O_5-Bi_2O_3-V_2O_5$, we could abtain glass-ceramics having crystal phase, LiV3O8 from glass matrix. The material heat-treated at lower-temperature, $250^{\circ}C$ had less crystalline and lower capacity, But the material heat-treadted at higher-temperature, $330^{\circ}C$ had higher capacity and $Li_2O-P_2O_5-V_2O_5$ glass-ceramics had higher capacity than $Li_2O-P_2O_5-Bi_2O_3-V_2O_5$ glass-ceramics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.311-315
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• 2000

Vanadate glass in the $LiO_2-P_2O_5-Bi_2O_3-V_2O_5$ system containing 10mol% glass fonner, $P_2O_5$ and $Bi_2O_3$ was prepared by melting the batch in pt. crucible followed by Quenching on the copper plate. We found that $LiO_2-P_2O_5-Bi_2O_3-V_2O_5$ glass-ceramics obtained from nucleation of glass showed signifieantly higher capacity and longer cycle life than conventionally made crystalline $LiV_3O_{8}$. In the present paper, we describe the charge / discharge properties during crystallization process and find the best crystallization condition of $LiO_2-P_2O_5-Bi_2O_3-V_2O_5$ glass as cathod material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.523-527
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• 2000

Vanadate glasses in the Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ system containing 10mo1% glass former, P$_2$O$_{5}$ were prepared by melting the batch in pt. crucib1e followed by quenching on the copper plate. We found that Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics obtained from nucleation of glass showed significantly higher capacity and longer cycle life than conventionally made crystalline LiCoO$_2$, LiNiO$_2$and LiV$_3$O$_{8}$. In the present paper, We describe electro-chemical properties during crystallization process and find the best crystallization condition of Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ g1ass as cathod material. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics shows superior rechargeable capacity of 220 mAh/g in the cycling between 2.0 and 3.9V.etween 2.0 and 3.9V.

• 자원환경지질
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• 제44권5호
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• pp.373-386
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• 2011

옥천변성대의 대표적인 우라늄 광화대인 괴산군 덕평리 일대의 흑색점판암과 이에 협재하는 함우라늄 탄질점판암을 상호 구분하여 이들에 대한 지구화학적 연구를 수행함으로써 우라늄 광상의 생성환경에 대해 고찰하였다. 희토류원소 함량은 탄칠점판암이 평균 254 ppm로서 혹색점판암(169 ppm) 보다 높고, 표준시료로 표준화한 결과 탄질시료의 Eu이 현저히 부화되어 나타난다. 산화환원지시원소에 해당하는 원소들의 경우 V, Cr, Co, Ni, Mo, 및 U 등이 흑색점판암에 비해 탄질점판암에서 현저히 부화되어 있는데, 특히, V은 흑색점판암에 비해 24배, Mo은 62배, U은 60배 가량 높게 산출된다. 이 밖에 백금족원소의 경우 Pd와 Pt가 탄질점판암에서 높은 함량을 나타낸다. 정의 Eu 이상을 비롯해 표준 해수기원 셰일에 비해 현저히 부화된 상기 원소들의 산출은 이들이 단순한 해수로부터 침전된 것이 아닌 고온의 환원환경인 해저열수활동과 관련된 퇴적환경에서 생성되었음을 시사한다. 넓은 조성변화를 나타내는 주성분 원소비 ($SiO_2/Al_2O_3$: 3.98~11.88, $Al_2O_3/Na_2O$: 25.6~139.06, $K_2O/Na_2O$: 6.80~46.85)도 퇴적물의 근원암이 퇴적암과 화성암이 혼재되었을 가능성을 나타내며, 또한 황의 함량이 흑색점판암에서 평균 0.6 wt.%인 반면, 탄질점판 암에서는 2.6 wt.%로 높게 나타나는 것은 탄질점판암이 황을 다량 포함하는 열수환경의 영향을 받았음을 보여준다. 이와 같은 지화학적 특징은 옥천변성대와 지구조적으로 대비되며 퇴적분기성 기원으로 알려진 남중국형 백금족광상(Mo-Ni-Zn-PGE)의 생성환경과도 유사한 특징이다. 이상으로 보아 덕평려 일대 우라늄광화작용은 해저열수활동의 영향을 받고 산소가 결핍된 유기물이 풍부한 퇴적분지에서 형성된 것으로 해석된다.