• Bulletin of the Korean Chemical Society
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• 제21권12호
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• pp.1233-1238
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• 2000

$Mo/{\gamma}-Al_2O_3catalysts$ modified with Fe, Co, and Ni were prepared by impregnation method and catalytic activity for water gas shift reaction was examined. The optimum amount of Mo loaded for the reaction was 10 wt% $MoO_3$ to ${\gamma}-Al_2O_3.$ The catalytic activity of $MoO_3/{\gamma}-Al_2O_3was$ increased by modifying with Fe, Co, and Ni in the order of Co${\thickapprox}$ Ni > Fe. The optimum amounts of Co and Ni added were 3 wt% based on CoO and NiO to 10 wt% $MoO_3/{\gamma}-Al_2O_3$, restectively. The TPR (temperature-programmed reduction) analysis revealed that the addition of Co and Ni enganced the reducibility of the catalysts. The results of both catalytic activity and TPR experiments strongly suggest that the redox property of the catalyst is an important factor in water gas shift reaction on the sulfided Mo catalysts, which could be an evidence of oxy-sulfide redox mechanism.

• Journal of the Mineralogical Society of Korea
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• 제2권1호
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• pp.8-10
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• 1989

Sphene from the McDonald pegmatite near Bancroft, Ontario, Canada was analyzed using EPMA. It contains 4.3 to 6.3 weight percent of Nb2O5 with an average formula Ca1.02(Ti0.62Al0.22Nb0.07Fe0.06Ta0.01)Si0.99(O4.85F0.16). Three types of subtitutions are possible; 1)2Ti4+=(Nb, Ta)5+ + (Al, Fe3+), 2) Ti + O = (Al, Fe3+) + (F, OH), and 3) 2Ti + O = Fe2+ + (Nb, Ta)5+ + (F, OH). T재 different schemes of substitutions for balancing the analysis are considered when the iron is either all ferric or all ferrous. Assuming stoichiometry fo Ca and Si, a general formula derived from the two different schemes is Ca(Ti0.64Al0.22Fe3+0.06-X {{{{Fe_{x}^{2+} }} Nb0.01)Sio4.80-XF0.16(OH)0.04+x.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2001년도 추계 학술발표강연 및 논문개요집
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• pp.116-116
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
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• pp.31-31
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• 1999

• Korean Journal of Metals and Materials
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• 제47권6호
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• pp.344-348
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• 2009

Dense $4.25Co_{0.53}Fe_{0.47}-Al_{2}O_{3}$ composite was simultaneously synthesized and consolidated by pulsed current activated combustion method within 2 min from mechanically activated powders. Consolidation was accomplished under the combined effects of a pulsed current and mechanical pressure. Dense $4.25Co_{0.53}Fe_{0.47}-Al_{2}O_{3}$ with relative density of up to 96% was produced under simultaneous application of 80 MPa pressure and the pulsed current. Fracture toughness and hardness of the composite are $6MPa{\cdot}m^{1/2}$ and $570kg/mm^{2}$ respectively.

• Korean Journal of Metals and Materials
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• 제47권11호
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• pp.754-758
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• 2009

Dense $5Cu_{0.6}Fe_{0.4}-Al_{2}O_{3}$ composite was consolidated from mechanically synthesized powders by high frequency induction heating method within 2 min. Consolidation was accomplished under the combined effects of a induced current and mechanical pressure. Dense $5Cu_{0.6}Fe_{0.4}-Al_{2}O_{3}$ with relative density of up to 95% was produced under simultaneous application of a 80 MPa pressure and the pulsed current. Fracture toughness and hardness of the composite are $7.6MPa{\cdot}m^{1/2}$ and $844kg/mm^{2}$ respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2000년도 추계학술발표강연 및 논문개요집
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• pp.155-155
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• 2000

• Journal of the Korean institute of surface engineering
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• 제34권2호
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• pp.135-141
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• 2001

Arc-melted Ti-6Al-4V, Ti-4Fe and Ti-(1,2) Si alloys were oxidized at 700, 800, 900 and $1000^{\circ}C$ in air. The oxidation resistance of Ti-4Fe was comparable to that of Ti-6Al-4V, while the oxidation resistance of Ti-(1,2) Si was superior to that of Ti-6Al-4V. Ti-2Si displayed the best oxidation resistance among the four alloys, but failed after oxidation at $1000^{\circ}C$ for 17h. The oxide scale formed on Ti-6Al-4V, Ti-4Fe and Ti-(1,2)Si consisted of ($TiO_2$ and a small amount of $Al_2$$O_3$), ($TiO_2$ and a small amount of dissolved iron), and ($TiO_2$ plus a small concentration of amorphous $SiO_2$), respectively. The oxide grains of the surface scale of the four alloys were generally fine and round.

• Journal of Powder Materials
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• 제16권2호
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• pp.91-97
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• 2009

Nanopowders of $Co_3O_4$ and FeAl were fabricated by high energy ball milling. Dense 4.25 $Co_{0.53}Fe_{0.47}-Al_2O_3$ composite was simultaneously synthesized and consolidated by high frequency induction heated combustion method within 2 min from mechanically activated powders. Consolidation was accomplished under the combined effects of a induced current and mechanical pressure of 80 MPa.

• Journal of the Korean Ceramic Society
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• 제31권3호
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• pp.235-240
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• 1994

The electric and magnetic properties of Mg1.9-2xMn0.05Fe4xO4+${\gamma}$+2wt% Al2O3, and its microstructure have been investigated as a function of ferrite composition (x=0.45, 0.5, 0.55). The microstructure turned out to be independent on the ferrite composition. The resistivity was decreased with increasing Fe contents, whereas the Curie temperature decreased. Saturation magnetization was varied from 1741 to 2022 G with composition, and squareness ratio (SR), coercive force (BHc) were decreased and increased with increasing Fe contents respectively, so the sample which SR and BHc were 0.97 Oe and 1.49 Oe can be attainable at x=0.45.