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Rang Seong-Min;An Sung-Yong;Kwon Hyuck-Mo;Kwon Se-Jin
- Proceedings of the Korean Society of Propulsion Engineers Conference
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- 2005.11a
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- pp.329-334
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- 2005
The rocket grade hydrogen peroxide has been widely used as a monopropellant in propulsion systems. Conventional decomposition of hydrogen peroxide, however, requires preheating before feeding into the reactor. In the present paper, we described an experimental study of a catalytic reactor bed that employs multiple catalysts to enhance the low temperature response in the vicinity of the reactor inlet. $K_2MnO_4$ is experimentally chose as the inlet catalyst from the candidates of silver, platinum, $La_{0.8}Sr_{0.2}CoO_3(LSC),\;and\;K_2MnO_4$. We developed new synthesis and coating method using modified alumina sol-gel method to strengthen the adhesion of $K_2MnO_4$ catalyst. from the vaporizer experiment with hydrogen peroxide at room temperature, satisfactory vaporizing performance was measured.
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Kim, Ki-Woon;Kang, Sei-Sun;Lee, Rhim-Youl
- Korean Journal of Materials Research
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- v.10 no.1
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- pp.49-54
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- 2000
The new green $Al_3GdB_4O_{12}:Tb^{3+} and red Al_3GdB_4O_{12}:Eu_{3+}$ phosphors were synthesized and then characterized their optical properties for PDP application. And also the photoluminescence properties of these phosphors were compared with the commercial green $Zn_2SiO_4:Mn^{2+} and (Y,Gd)BO_3: Eu^{3+}$ red PDP phosphors. The phosphors were synthesized by solid state reaction at 115$0^{\circ}C$ for 4hr. It was found that the emitting brightness of $Al_3GdB_4O_{12}:Tb^{3+}$(15mol%) green phosphor under 147nm excitation was higher than that of commercial $Zn_2SiO_4: Mn^{2+}$ green PDP phosphor. However, the color coordinate of this new green phosphor was inferior to the commercial one. On the other hand, the emitting intensity of $Al_3GdB_4O_{12}:Eu^{3+}$(15mol%) red phosphor was smaller than the $commercial(Y,Gd)BO_3: Eu^{3+}$ red one, but the CIE coordinate was slightly improved. The excitation spectrum showed that $Al_3GdB_4O_{12}$ phosphors had a strong excitation band at $\lambda=160nm$ associated with the host absorption. And the photoluminance excitation (PLE) intensity in VUV range for $Al_3GdB_4O_{12}:Tb^{3+}$ green phosphor was higher than that of $Zn_2SiO_4: Mn^{2+}$, but the PLE intensity of $Al_3GdB_4O_{12}:Eu^{3+}$ red phosphor was smaller than $(Y,Gd)BO_3: Eu^{3+}$.
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백수현;조현춘
- Journal of the Korean Institute of Telematics and Electronics
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- v.24 no.6
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- pp.980-985
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- 1987
The thin metal films of Cr, Al, Mn and were made in various evaporation rates with 100\ulcornerthickness under 2x10**-9 bar vacuum level. We analized and discussed the relationships between changes of structure, morphology and sheet resistance, light transmittance for the corresponding evaporation rates. As the evaporation rates were decreased at higher rates, grain sizes of all film were decreased, however both of the sheet resistance and light transmittance were increased. At lower evaporation rate, films of Cr and Cu porduced non-stoi-chiometric oxides but Al an Mn showed up amorphous structures.
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이상원;최동혁;안성용;손지희;김철성
- Proceedings of the Korean Magnestics Society Conference
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- 2002.12a
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- pp.112-113
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- 2002
M-type hexa-ferrite BaFe$_{12}$O$_{19}$는 높은 보자력과 함께 화학적으로 안정하고 높은 전기 저항을 가지고 있어서 영구자석으로 아주 우수한 특성을 가지고 있으며, 고밀도 자기 기록매체로서 각광을 받고 있을 뿐만 아니라 microwave용이나 고주파 장치의 소자, 전파흡수체 및 전파 차폐제로서 주목받고 있는 재료이다. (중략)략)
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Lee, Chul-Wee
- Journal of the Korean Magnetic Resonance Society
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- v.6 no.2
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- pp.113-117
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- 2002
The chalcogenide glass (ALS, $Al_2S_3-La_2S_3$) was prepared by melting a stoichiometric mixture of aluminum powder and $La_2S_3$ under $H_2S$ atmosphere at $1200{\circ}C$. Glasses containing 0.1-0.1% of $Mn^{2+},\;Gd^{3+}$ and $Cu^{2+}$ were also prepared. The characteristic features of the ESR spectra for the transition metal containing ALS glasses are interpreted.
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