• Transactions of the Korean hydrogen and new energy society
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• v.9 no.2
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• pp.47-52
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• 1998

A mixture with a composition $Mg_2Ni$ is mechanically alloyed. Its hydriding and dehydriding properties are compared with those of the intermetallic compound $Mg_2Ni$ prepared by partial melting and sintering. The principal effects of mechanical alloying in a planetary mill and hydriding-dehydriding cycling are considered the enlargement in the specific surface area and the augmentation in the density of defects.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.846-847
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• 2006

The composite used in this paper was prepared by hot-pressing ball-milled Mg alloy powders, in which NiTi shape memory alloy fibers in a row were sandwiched. The microstructure and property were examined. It is shown that the composite consisted of a homogenous matrix with uniformly distributed NiTi shape memory alloy fibers, recrystallization took place in the Mg alloy matrix which was subjected to plastic deformation an adequate bonding formed between the matrix and fibers; the density and tensile strength of the composite increased after the hot-forging; the hot-forging process is capable of improving properties of the composite.

• 한국전기화학회:학술대회논문집
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• 1999.10a
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• pp.51-51
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• 1999

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.171-171
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.93.2-93
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.11a
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• pp.37-37
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.446-452
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• 2000

This study was carried out to investigate the effect of mine activity on paddy fields, agricultural water, and plants in the ruined Oksung Cu-Zn mine area. Soil samples collected from paddy fields adjacent to the Cu-Zn mine sites were sequentially extracted and determined the contents of heavy metals such as Cd, Zn, Cu, Pb, Cr and Ni. Distribution of exchangeable heavy metals in soils was 30.2% of Cd, 11.3% of Zn, 2.2% of Cu, 4.6% of Cr, 0.6% of Pb and 3.9% of Ni. Water soluble heavy metals were only detected with Zn. The contents of heavy metals in water collected from the mine were 0.01 of Cd, 27.35 of Zn, 4.86 of Cu, 1.04 of Pb, 0.03 of Cr and $0.08mg\;L^{-1}$ of Ni. while the contents in waler collected out of the mine were 16.67 of Zn, 0.59 of Cu, 0.49 of Pb, 0.05 of Cr and $0.06mg\;L^{-1}$ of Ni. On the other hand, agricultural water near mine area were 1.26 of Zn, 0.05 of Cu, 0.05 of Pb and $0.02mg\;L^{-1}$ of Ni. Both Cd and Cr were not detected in the agricultural water.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.321-328
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• 2011

The autothermal reforming reaction of methane was investigated to produce hyd rogen with Ni/$CeO_2-ZrO_2$, Ni/$Al_2O_3$-MgO and Ni-Ru/$Al_2O_3$-MgO catalysts. Honeycomb metalli c monolith was applied in order to obtain high catalytic activity and stability in autothermal r eforming. The catalysts were characterized by XRD, BET and SEM. The influence of various catalysts on hydrogen production was studied for the feed ratio($O_2/CH_4$, $H_2O/CH_4$). The $O_2/CH_4$ and $H_2O/CH_4$ ratio governed the methane conversion and temperature profile of reactor. Th e reactor temperature increased as the reaction shifted from endothermic to exothermic reactio n with increasing $O_2/CH_4$ ratio. Among the catalysts used in the experiment, the Ni-Ru/$Al_2O_3$-MgO catalyst showed the highest activity. The 60% of $CH_4$ conversion was obtained, and th e reactor temperature was maintained $600^{\circ}C$ at the condition of GHSV=$10000h^{-1}$ and feed ratio S/C/O=0.5/1/0.5.

• Clean Technology
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• v.9 no.3
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• pp.125-132
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• 2003

Activity improvement of Ni metal catalysts for carbon dioxide reforming was studied using HY-zeolite as the main supporter. As the reaction temperature increased, $CH_4$ and $CO_2$ conversions increased, and conversions higher than 80% was obtained above $700^{\circ}C$. As the Ni loading increased, the catalyst activity increased, and the highest activity was shown for the Ni loading of 13wt%. The HY-zeolite support showed the highest intial conversions of $CH_4$ and $CO_2$, but it showed faster deactivation than a ${\gamma}-Al_2O_3$ support. Nevertheless, it maintained the $CH_4$conversion higher than 80% after 24 hr reaction. The effect of promoters such as Mg, Mn, K, and Ca was also studied. It was observed that the Mg promotor exhibited the highest catalyst activity and less deactivation compared with Mn, K and Ca. After 24hr reaction, The optimum Mg content was found to be 5wt%.

• Korean Journal of Materials Research
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• v.25 no.1
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• pp.43-47
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• 2015

$Zn(BH_4)_2$ was prepared by milling $ZnCl_2$ and $NaBH_4$ in a planetary ball mill in an Ar atmosphere, and XRD analysis, SEM observation, FT-IR analysis, DTA, and TGA were performed for synthesized $Zn(BH_4)_2$ samples. 90 wt% $MgH_2$+1.67 wt% $Zn(BH_4)_2(+NaCl)$+5 wt% Ni+1.67 wt% Ti+1.67 wt% Fe (named $90MgH_2+1.67Zn(BH_4)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe) samples were also prepared by milling in a planetary ball mill in an $H_2$ atmosphere. The gas absorption and release properties of the $Zn(BH_4)_2(+NaCl)$ and $90MgH_2+1.67Zn(BH_4)_2(+NaCl)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe samples were investigated. An FT-IR analysis showed that $Zn(BH_4)_2$ formed in the $Zn(BH_4)_2(+NaCl)$ samples prepared by milling $ZnCl_2$ and $NaBH_4$. At the first cycle at $320^{\circ}C$, $90MgH_2+1.67Zn(BH_4)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe absorbed 2.95 wt% H for 2.5 min and 4.93 wt% H for 60 min under 12 bar $H_2$, and released 1.46 wt% H for 10 min and 4.57 wt% H for 60 min under 1.0 bar $H_2$.