• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.145-156
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• 2003

The atmospheric aerosols collected at the 1100 site located in Mt. Halla have been analyzed to investigate their compositions and chemical characteristics . The average concentrations of water-soluble cations were in the order of N $H_{4}$$^{+}$ > $Ca^{2+}$ > N $a^{+}$ > $K^{+}$ > $Mg^{2+}$ during the spring, showing high increase of $Ca^{2+}$ concentration with the value of 0.60 $\mu\textrm{g}$/ $m^3$, and N $H_{4}$$^{+}$> N $a^{+}$> $K^{+}$> $Ca^{2+}$ > $Mg^{2+}$ during the other seasons. The average concentrations of anions have shown in the order of S $O_{4}$$^{2-}$ > N $O_{3}$$^{[-10]}$ >C $l^{[-10]}$ for all seasons, and S $O_{4}$$^{2-}$ and N $O_{3}$$^{[-10]}$ had higher concentrations in spring with the values of 4.84 $\mu\textrm{g}$/ $m^3$ and 1.08 $\mu\textrm{g}$/ $m^3$, respectively. From the analytical data of size-segregated particles by cascade impactor sampling, the components of N $H_{4}$$^{+}$, S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and $K^{+}$ were distributed mainly in fine particles, but $Ca^{2+}$, N $a^{+}$, $Mg^{2+}$ and C $l^{[-10]}$ were included mostly in coarse particles. The correlation coefficients of nss-S $O_{4}$$^{2-}$/N $H_{4}$$^{+}$, nss-S $O_{4}$$^{2-}$/ $K^{+}$ and N $O_{3}$$^{[-10]}$ /nss-C $a^{2+}$ showed quite high values with 0.871, 0.857 and 0.654, respectively Based on the study of enrichment factors, it is considered that N $a^{+}$, $Mg^{2+}$, C $l^{[-10]}$ and $Ca^{2+}$ components were delivered from oceanic and soil sources, but S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and N $H_{4}$$^{+}$ might have other source origins. The factor analysis study showed the aerosol at the 1100 site was influenced mainly by anthropogenic factors, followed by oceanic and soil factors. followed by oceanic and soil factors.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.997-1004
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• 2003

The objective of this research was to test whether, under controlled laboratory conditions, hybrid SNCR/SCR process improves N $O_{x}$ removal efficiency in comparison with the SNCR only. The hybrid process is a combination of a redesigned existing SNCR with a new downstream SCR. N $O_{x}$ reduction experiments using a hybrid SNCR/SCR process have been conducted in simple NO/N $H_3$/ $O_2$ gas mixtures. Total gas flow rate was kept constant 4 liter/min throughout the SNCR and SCR reactors, where initial N $O_{x}$ concentration was 500 ppm in the presence of 5% or 15% $O_2$. Commercial catalysts, $V_2$ $O_{5}$ -W $O_3$-S $O_4$/Ti $O_2$, were used for SCR N $O_{x}$ reduction. The residence time and space velocity were around 1.67 seconds and 2,400 $h^{-1}$ or 6000 $h^{-1}$ in SNCR and SCR reactors, respectively. N $O_{x}$ reduction of the hybrid system was always higher than could be achieved by SNCR alone at a given value of N $H_{3SLIP}$. Optimization of the hybrid system performance requires maximizing N $O_{x}$ removal in the SNCR process. An analysis based on the hybrid system performance in this lab-scale work indicates that a equipment with N $O_{xi}$ =500 ppm will achieve a total N $O_{x}$ removal of about 90 percent with N $H_{3SLIP}$ $\leq$ 5 ppm only if the SNCR N $O_{x}$ reduction is at least 60 percent. A hybrid SNCR/SCR process has shown about 26∼37% more N $O_{x}$ reduction than a SNCR unit process in which a lower temperature of 85$0^{\circ}C$ turned out to be more effective.be more effective.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1413-1414
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• 2003

Interannual variability in the patterns of satellitederived pigment concentrations, sea-level height anomaly, sea surface temperature anomaly, and zonal wind anomaly are observed during the 2002-2003 El Ni${\tilde{n}}$o. The largest spatial extent of the phytoplankton bloom was recovery from El Ni${\tilde{n}}$o over the equatorial Pacific. The evolution towards a warm episode (El Ni${\tilde{n}}$o) started from spring of 2002 and continued during January 2003, while equatorial Sea Surface Temperature Anomaly (SSTA) remained greater than +1$^{\circ}$C in the central equatorial Pacific. The EOS (Earth Observing System) and OSMI (Ocean Scanning Multispectral Imager) data are used for detection of dramatic changes in the patterns of pigment concentration during El Ni${\tilde{n}}$o.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.1
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• pp.23-28
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• 1996

In order to investigate the chemical components of acid precipitation at Samchok City in Korea, the rainwater was collected according to 3mm rainfall from september 1994 to december 1994. pH, electric conductivity were measured and ionic components were analyzed by Ion chromatography. As the analytical results, the average value were 6.27 for pH, 53.16 S/cm for E.C., the average concentration were 393.42 eq/1 for C $l^{[-10]}$ , 18.41 eq/1 for N $O_{3}$$^{[-10]}$ , 91.44 eq/1 for S $O_{4}$$^{2-}$, 335.92 eq/1 for N $a^{+}$, 65.66 eq/1 for N $H_{4}$$^{+}$, 18.22 eq/1 for $K^{+}$, 120.49 eq/1 for $Mg^{2+}$ and 147.04 eq/1 for $Ca^{2+}$. pH value correlated negatively with rainfall amount and the component of C $l^{[-10]}$ and N $a^{+}$ were transported to urban air by the seasalt. It showed that S $O_{4}$$^{2-}$ and N $O_{3}$$^{[-10]}$ had influence on acidity of precipitation, 73% and 27%, respectively, in this area. Ion Concentration of N $O_{3}$$^{[-10]}$ was higher than S $O_{4}$$^{2-}$ in the early rain, S $O_{4}$$^{2-}$ was higher than N $O_{3}$$^{[-10]}$ in the succeeding rain by multi-regration analysis. the percentages of removal by percipitation were higher in N $O_{3}$$^{[-10]}$ than in S $O_{4}$$^{2-}$./TEX> 2-/.

• Journal of ILASS-Korea
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• v.25 no.3
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• pp.132-138
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• 2020

N₂O is hazardous atmosphere pollution matter which can damage the ozone layer and cause green house effect. There are many other nitrogen oxide emission control but N₂O has no its particular method. Preventing further environmental pollution and global warming, it is essential to control N₂O emission from industrial machines. In this study, the thermal decomposition experiment of N₂O gas mixture is conducted by using cylindrical reactor to figure out N₂O reduction and NO formation. And CHEMKIN calculation is conducted to figure out reaction rate and mechanism. Residence time of the N₂O gas in the reactor is set as experimental variable to imitate real SNCR system. As a result, most of the nitrogen components are converted into N2. Reaction rate of the N₂O gas decreases with N₂O emitted concentration. At 800℃ and 900℃, N₂O reduction variance and NO concentration are increased with residence time and temperature. However, at 1000℃, N₂O reduction variance and NO concentration are deceased in 40s due to forward reaction rate diminished and reverse reaction rate appeared.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.4
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• pp.32-35
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• 1979

When photon was injected to SnO2- amorphous Sb S thin film -Sn structure through the window of SnO2, photo- voltaic effect was observed. With the energy change of photon, photovoltage had either positive or negative value This phenomenon was considered to be caused by formation of n-n heterojunction in SnO2 - Sb S structure and Schottky junction Sb S -Sn structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.412-418
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• 2000

In this paper, we will propose that HCN(n,n) gets Hamiltonian Cycles and analyze embedding among HCN(n,n) and UFN(n,n), and HFN(n,n) and In-hypercube. Further, we will prove that HCN(n,n) can be embedded into HFN(n,n) with dilation 3 and the cost for HFN(n,n) to be embedded into HCN(n,n) will be O(n), and HW(n,n) can be embedded into 2n-hypercube with dilation 3 and the cost for In-hypercube to be embedded into HFN(n,n) will be O(n).

• Cross-Cultural Studies
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• v.25
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• pp.267-290
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• 2011

The purpose of this study is examining a circulation and conflict of concepts and logics of the $Chos{\check{o}}n$-ness by analysing the $Chos{\check{o}}n$ national character and $Chos{\check{o}}n$ aesthetic consciousness. As entering the modern period, we understood the nations as a unit of the artistic awareness. So, national art is defined as a national character expression from this period. The $Chos{\check{o}}n$ aesthetic consciousness by raising in this period, which is connected with the discourse of national character, carry out a discussional practice defining the Korean originality. However, there is a circulation and conflict of concepts and logics about the $Chos{\check{o}}n$ aesthetic consciousness in the process of a discussion. For the most representative examples are 'the white-clad folk' and 'the beauty of sorrow'. An Hwak and Yanagi Muneyoshi are representative debaters who try to establish the $Chos{\check{o}}n$-ness and their discussion supports these facts. As An Hwak regressing of the respect for high antiquity, he demolished the historical character from the $Chos{\check{o}}n$-ness and overlooked aesthetic differences by a periodical change. Yanagi Muneyoshi totally separates arts from politics and disposes of Korean arts in an abstract timeless-space. The function of such an early-modern period's discourse about $Chos{\check{o}}n$ aesthetic consciousness is that $Chos{\check{o}}n$ national character makes the dehistoricization and depoliticization.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.681-689
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• 2019

The $M{\ddot{o}}bius$ homogeneous submanifold in ${\mathbb{S}}^{n+1}$ is an orbit of a subgroup of the $M{\ddot{o}}bius$ transformation group of ${\mathbb{S}}^{n+1}$. In this note, We prove that a compact $M{\ddot{o}}bius$ homogeneous submanifold in ${\mathbb{S}}^{n+1}$ is the image of a $M{\ddot{o}}bius$ transformation of the isometric homogeneous submanifold in ${\mathbb{S}}^{n+1}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.403-406
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• 2000

The piezoelectric properties and the doping effect of N $b_2$ $O_{5}$ and Mn $O_2$for 0.95PbZ $r_{x}$ $Ti_{x}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$ compositions have been investigated. In the composition of 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$the Values Of $k_{p}$ find and $\varepsilon$$_{33}$ $^{T}$ are maximized, but $Q_{m}$ Was minimized ( $k_{p}$ =0.51, $Q_{m}$ =1750). The grain size was suppressed and the uniformity of grain was improved with doping concentration of N $b_2$ $O_{5}$ for 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.005Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$sample. The values of $k_{p}$ increased and the values of $Q_{m}$ slightly decreased when 0.5 wt% of N $b_2$ $O_{5}$ is doped. And the values of $k_{p}$ was the same formation of the N $b_2$ $O_{5}$ dopant when 0.5 wt% of M $n_2$ $O_{5}$ is doped. But the values of $Q_{m}$ was deeply decreased when 0.5 wt% of Mn $O_2$is doped. As a experiment results under high electric field driving, this piezoelectric ceramics are very stable. Conclusively, piezoelectric ceramic compsiton investigated at this paper is suitable for application to high power piezoelectric devices.. devices..ices.. devices..