• Korean Journal of Materials Research
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• v.16 no.3
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• pp.145-150
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• 2006

Various colors of light emitting diodes(LED) and four-band white light sources are obtained using a violet LED and various phosphor films. $BaMg_2Al_{16}O_{27}:Eu\;(blue),\;SrGa_2S_4:Eu\;(green),\;and\;Eu(TTA)_3(PTA)$ (red) phosphors are dispersed in poly-vinyl-alcohol aqueous solutions, and phosphor films are prepared by coating the suspensions to PET film. The narrow band emission of $Eu(TTA)_3(PTA)$ phosphor has excellent red luminescent property for four-band white light excited by the violet LED.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.31.2-31.2
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• 2007

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.137-140
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• 2006

The prototype of the field emission display with carbon nanotube emitter is developed in this study. To improve the brightness and color gamut of the prototype, new phosphor material, $SrGa_2S_4:Eu$, is adopted instead of conventional CRT-green phosphor. By replacing the green phosphor, the prototype shows significant improvements in the brightness and color gamut. At the anode voltage of 7 kV and the anode current of $2{\sim}3\;{\mu}A/cm^2$ the brightness is higher than $600\;cd/m^2$. The luminous efficiency of the prototype is about 7.7 lm/Watt.

• The Journal of the Petrological Society of Korea
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• v.4 no.1
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• pp.31-48
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• 1995

The Jurassic Kwanaksan stock, so far known to be composed of biotite granite only, has the mineral assemblage of quartz+K-feldspar+plagioclase+biotite${\pm}$gernet. The lithology of the stock is classified as alkali feldspar granite by their mode and plagioclase compositions (An<5). Subsolvus feldspars, rather early crystallization of biotite, and shallow emplacement depth estimated from Q-Ab-Or diagram suggest hydrous nature of the magma, which contrasts with anhydrous A-type like geochemistry described below. Major and trace element compositions of the Kwanaksan stock are distinct from those of the adjacent Seoul batholith, suggesting a genetic difference between the two, The Kwanaksan stock shows geochemical characteristics similar to A-type granite in contrast to most other Mesozoic granites in Korea, in that it has high $SiO_2$(73~78wt%), $Na_2O+K_2O$, Ga(27~47 ppm). Nb(22~40 ppm), Y(48~95 ppm), Fe/Mg and Ga/Al, and low CaO(<0.51 wt%). Ba (8~75 ppm) and Sr(2~23 ppm). However, it has lower Zr and LREE and higher Rb(384~796 ppm) than typical A-type granite. LREE-depleted rare earth element pattern with strong negative Eu anomaly of previous studies is reinterpreted as representing source magma characteristics. The residual material during partial melting is not compatible with pyroxenes, amphibole or garnet, while significant amount of plagioclase is required. Similarity of geochemistry of the Kwanaksan stock to A-type granite suggests the origin of the stock has a chose relationship with that of A-type granite. These observations lead us to propose that the Kwanaksan stock was formed by partial melting of felsic source rock.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.179-198
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• 2013

The Boziguoer A-type granitoids in Baicheng County, Xinjiang, belong to the northern margin of the Tarim platform as well as the neighboring EW-oriented alkaline intrusive rocks. The rocks comprise an aegirine or arfvedsonite quartz alkali feldspar syenite, an aegirine or arfvedsonite alkali feldspar granite, and a biotite alkali feldspar syenite. The major rock-forming minerals are albite, K-feldspar, quartz, arfvedsonite, aegirine, and siderophyllite. The accessory minerals are mainly zircon, pyrochlore, thorite, fluorite, monazite, bastnaesite, xenotime, and astrophyllite. The chemical composition of the alkaline granitoids show that $SiO_2$ varies from 64.55% to 72.29% with a mean value of 67.32%, $Na_2O+K_2O$ is high (9.85~11.87%) with a mean of 11.14%, $K_2O$ is 2.39%~5.47% (mean = 4.73%), the $K_2O/Na_2O$ ratios are 0.31~0.96, $Al_2O_3$ ranges from 12.58% to 15.44%, and total $FeO^T$ is between 2.35% and 5.65%. CaO, MgO, MnO, and $TiO_2$ are low. The REE content is high and the total ${\sum}REE$ is $(263{\sim}1219){\times}10^{-6}$ (mean = $776{\times}10^{-6}$), showing LREE enrichment HREE depletion with strong negative Eu anomalies. In addition, the chondrite-normalized REE patterns of the alkaline granitoids belong to the "seagull" pattern of the right-type. The Zr content is $(113{\sim}1246){\times}10^{-6}$ (mean = $594{\times}10^{-6}$), Zr+Nb+Ce+Y is between $(478{\sim}2203){\times}10^{-6}$ with a mean of $1362{\times}10^{-6}$. Furthermore, the alkaline granitoids have high HFSE (Ga, Nb, Ta, Zr, and Hf) content and low LILE (Ba, K, and Sr) content. The Nb/Ta ratio varies from 7.23 to 32.59 (mean = 16.59) and the Zr/Hf ratio is 16.69~58.04 (mean = 36.80). The zircons are depleted in LREE and enriched in HREE. The chondrite-normalized REE patterns of the zircons are of the "seagull" pattern of the left-inclined type with strong negative Eu anomaly and without a Ce anomaly. The Boziguoer A-type granitoids share similar features with A1-type granites. The average temperature of the granitic magma was estimated at $832{\sim}839^{\circ}C$. The Boziguoer A-type granitoids show crust-mantle mixing and may have formed in an anorogenic intraplate tectonic setting under high-temperature, anhydrous, and low oxygen fugacity conditions.