• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.878-883
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• 1998

The methane combustion reaction was conducted over Pb-ZSM-5 catalysts. ZSM-5 synthesized at low temperature and atomospheric pressure was used as a support. The change of methane conversion with $SiO_2/Al_2O_3$ molar ratio was tested. The methane conversions of the synthesized Pb-ZSM-5 catalyst was compared with those of a commercial Pd-ZSM-5(PQ Co.) and $PdO/{\gamma}-Al_2O_3$. The methane conversion increased with the decrease in $SiO_2/Al_2O_3$ molar ratio. The combustion rate of methane also increased with the decrease in $SiO_2/Al_2O_3$ molar ratio. The synthesized Pb-ZSM-5 showed better methane conversion than that of the commercial one. It is found that a crucial factor in methane combustion reaction is oxygen adsorption strength on the catalysts.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1556-1571
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• 1993

Nitrogen oxides ($NO_x$) are air pollutants which are generated from the combustion of fossil fuels. Stage combustion is an effective method to reduce $NO_x$ emissions. The effects of $NO_x$ reduction by stage combustion in a pilot scale combustor(6.6kW) have been investigated using propane gas flames laden with NH$_{3}$ as Fuel-N. The results in this study are follows; (1) $NO_x$ emissions are dependent on the reducing environment of fuel-rich zone regardless of total air ratio. The maximum $NO_x$ reduction is at the stoichiometric ratio of 0.8 to 0.9 in the reducing zone. (2) $NO_x$ reduction is maximum when burnout air is injected at the point where the oxygen in reducing zone is almost consumed. (3) $NO_x$ reduction is dependent upon the temperature of reducing zone with best effect above 950.deg. C in the reducing zone. (4) The fuel stage combustion is more effective to reduce $NO_x$ formation in the wide range of stoichiometric ratio than two stage combustion. (5) The results of this study could be utilized mainly in a design strategy for low $NO_x$ emission from the combustion of high fuel-nitrogen in energy sources ratio than as an indication of the absolute levels of $NO_x$ which can be achieved by stage combustion techniques in large scale facilities.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.255-259
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• 1990

To investigate relative flammability in flaming combustion among 10 softwoods and 10 hardwoods, oxygen indices were determined for flat-grained sapwoods through Up and Down method following oxygen index test of ASTM D 2863-77. Oxygen index ranged from 21.0 for Pinus strobus to 28.2 for Larix gmelinii var. principis-ruprechtii in softwoods and from 20.7 for Populus davidiana to 27.6 for Quercus acntissima in hardwoods, which indicates Larix gmelinii var. principis-ruprechtii and Quercus acutissima being ranked first in inflammability and Pinus strobus and Populus davidiana being the least in fire resistance by softwood and hardwood because highly flammable materials are likely to have a low oxygen index.

• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.842-850
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• 2004

We have investigated on the preparation of BaTiO$_3$ powder at the system of BaO$_2$-TiO$_2$-Reduction ag.-PSCA by SHS. C and Mg were used as reduction agent, and NaCl was used as PSCA (Particle Size Control Agent). The effects of the various reduction agent and its concentration, particle size control agent, reaction mixture mass on the product in the preparation of BaTiO$_3$ powder at the optimum system by SHS were investigated. The optimum conditions for reaction system and composition were BaO$_2$+TiO$_2$+0.11 Mg +0.2C+0.75NaCl in the As atmosphere. NaCl as PSCA showed the effect of controlling the particle size of product as well as the combustion temperature. The particle size of BaTiO$_3$ synthesized at the optimum condition was about 0.5 ${\mu}{\textrm}{m}$. And as the mixture mass for the reaction was increased, the more stable combustion wave appeared. We have conducted the sintering experiment at the temperature of 130$0^{\circ}C$, the time of 2 h and the atmosphere of air to measure the dielectric properties of BaTiO$_3$ synthesised in this work, and the sample sintered in this condition showed 2,290 of dielectric constant at 10$0^{\circ}C$ and 13,890 at curie point (129$^{\circ}C$).

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.273-273
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• 1997

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.05a
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• pp.107-107
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• 1998

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.101-101
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.156-156
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• 2001

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.05a
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• pp.38-38
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• 2001

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.112.2-112.2
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• 2000