• Electrical & Electronic Materials
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• v.6 no.3
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• pp.269-275
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• 1993

미래의 ULSI 소자의 게이트 산화막으로 이용하기 위하여 $N_{2}$O 가스 분위기에서 기존의 전기로를 이용한 실리콘의 열산화에 의해 $N_{2}$O 산화막을 형성하였고 MOS 소자를 제작하여 전기적 특성을 고찰하였다. 900.deg.C에서 90분간 산화한 $N_{2}$O 산화막의 경우, 플랫밴드 전압( $V_{FB}$ ), 고정전하밀도 ( $N_{f}$)와 플랫밴드 전압의 변화량(.DELTA. $V_{FB}$ )은 각각 0.81[V], 6.7x$10^{10}$[$cm^{-2}$]와 80~95[mV]를 나타내었다. $N_{2}$O 산화막의 전기전도기구는 저전계 영역에서는 Fowler-Nordheim 터널링, 고전계영역에서는 Poole-Frenkel 방출이 지배적으로 나타났고 절연파괴전계는 16[MV/cm]로 높게 나타났다. 따라서 $N_{2}$O 산화로 형성된 게이트 산화막이 ULSI소자의 게이트 유전체로 응용이 가능하리라 생각된다..

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.5
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• pp.333-343
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• 1997

The cyclone/annular denuder system/filter pack sampling system (ADS) was used to collect the acidic air pollutants in Chongju city. The data set was collected on fifty -eight different days with 24 hour sampling period from October 27, 1995 through August 25, 1996. The chemical species measured were HN $O_3$, HN $O_2$, S $O_2$ and N $H_3$ in the gas phase, and PM2.5( $d_{p}$ ＜2.5 ${\mu}{\textrm}{m}$), S $O_4$$^{2-}$, N $O_3$$^{[-10]}$ and N $H_4$$^{+}$ in the Particulate Phase. Mean concentrations measured for this study were: 0.45 $\mu\textrm{g}$/㎥ for HN $O_3$, 3.39 $\mu\textrm{g}$/㎥ for HN $O_2$, 26.4 $\mu\textrm{g}$/㎥ for S $O_2$, 3.83$\mu\textrm{g}$/㎥ for N $H_3$, 44.2 $\mu\textrm{g}$/㎥ for P $M_{2.5}$, 8.22 $\mu\textrm{g}$/㎥ for S $O_4$$^{2-}$, 3.63 $\mu\textrm{g}$/㎥ for N $O_3$$^{[-10]}$ , and 2.84 $\mu\textrm{g}$/㎥ for N $H_4$$^{- }$. HN $O_3$ and N $H_3$ were higher during the summer. However, HN $O_2$ and S $O_2$ were higher during the fall and winter. P $M_{2.5}$ , S $O_4$/ sup 2-/ and N $H_4$$^{+}$ were not showed seasonal variations, but N $O_3$$^{[-10]}$ was higher in the winter.ter.r.

• Journal of the Korean Chemical Society
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• v.38 no.11
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• pp.808-818
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• 1994

The neutral compounds [$MCl_3L_2$(MeCN)] (M = Mo, V: L = $PPh_3$, 1/2 phda) have been prepared from the reaction of starting material $MCl_z$ (M = Mo; z = 5, M = V; z = 3) with N,P-donating ligands in acetonitrile solution. Addition of $AgClO_4$ to these neutral monomeric compounds in acetone solution were produced [$MCl_3-_nL_2(MeCN)(S)_n$]$(ClO_4)_n$ (n = 1, 2 : s = solvent). Finally treatment of bivalent cationic compound and neutral compound was formed chloride bridged dinuclear complex $[(MeCN)(L)_2ClM({\mu}-Cl)_2M'Cl(L)_2(MeCN)](ClO_4)_2$ and treatment of univalent cationic compound with half equivalent pyrazine to pyrazine bridged complex $[(MeCN)(L)_2Cl_2M({\mu}-pyz)M'Cl_2(L)_2(MeCN)](ClO_4)_2$. These complexes are characterized by elemental analysis, $^1H$, $^{13}C$ NMR, IR, Far-IR and UV-Vis spectroscopy.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.117-127
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• 1994

In this paper, electrical and reliability properties of N$_2$O oxides, grown at the temperature of 95$0^{\circ}C$ and 100$0^{\circ}C$ to 74$\AA$, and 82$\AA$. respectively, using NS12TO gas in a conventional furnace, have been compared with those of pure oxide grown at the temperature of 850 to 84$\AA$ using O$_2$ gas. Initial IS1gT-VS1gT characteristics of N$_2$O oxides were similar to those of pure oxide, and reliability properties of N$_2$O oxides, such as charge trapping, interface state density and leakage current at low electric field under F-N stress, were improved much better than those of pure oxide. But, with increasing capacitor area. TDDB characteristics of N$_2$O oxides were more degraded than those of pure oxide and this degradation of TDDB characteristics was more severe in 100$0^{\circ}C$ N$_2$Ooxide than in 95$0^{\circ}C$ N$_2$O oxide. The improvement of reliability properties excluding TDDB in N$_2$Ooxides was attributed to the hardness of the interface improved by nitrogen pile-up at the interface of Si/SiO$_2$, but on the other hand, the degradation of TDDB characteristics in N$_2$O oxides was obsered due to the increase of local thinning spots caused by excessive nitrogen at interface during the growth of N$_2$O oxides.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.223-224
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• 2009

본 연구에서는 $Cl_2$/Ar 기반의 플라즈마 식각에 $N_2$가스를 첨가하여 ZnO 박막을 식각 하였을 때 관찰된 ZnO 박막의 식각 특성에 관하여 연구 하였다. ZnO 박막 식각 실험은 RF 800 W, bias power 400 W, 공정 압력 15 mTorr를 기준으로 하였으며 가스 혼합 비율로는 최적의 식각률을 보여주는 $Cl_2$/Ar=8:2 비율에서 실행하였다. 연구의 목적인 첨가 가스 $N_2$를 $Cl_2$ (80%)/Ar (20)%에 5 sccm 씩 첨가하여 20 sccm 까지 증가 시켜 실험 하였다. $N_2$ 가스가 15 sccm 첨가되었을 때 식각률 95.9 nm/min로 기존 $Cl_2$/Ar 기반의 플라즈마 식각보다 높은 식각률을 보여 주었으며 $N_2$ 가스 흐름 조절 외에도 공정 압력, RF power, bias power를 변경하며 실험하였다. 식각된 ZnO 박막의 표면은 최대 식각률을 보이는 공정 조건을 찾기 위해 surface profiler ($\alpha$-step)을 이용하여 식각률을 측정하였으며 ZnO 박막 표면의 화학적인 변화를 조사하기 위해 x-ray photoelectron spectroscopy (XPS)를 사용하였다. XPS 분석 결과 Zn $2p_{3/2}$ peak 가낮은 binding energy 쪽으로 이동한 것을 관찰 할 수 있었다. 또한 O 1s 의 스펙트럼을 분석한 결과 N-O bond와 O-H bond가 존재함이 밝혀졌다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.701-703
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• 2000

본 논문에서는 정규 기저 표현(normal bases repersentation)을 갖는 GF(2n)상에서의 병렬 멱승 연산에 있어서 2 가지의 개선 사항을 기술한다. 첫째는,k를 윈도우 길이로 할 때 라운드가 [log k]+[log[n/k]]로 고정된 경우에 현재까지 알려진 방법보다 더 작은 수의 프로세서를 갖는 방안이다. 둘째는 점근적인(asymptotic)분석을 통하여 GF(2n)상에서의 병렬 멱승 연산이 O(n/log2n)개의 프로세서로 O(logn)라운드에 수행될 수 있음을 보인다. 이것은 m로세서 $\times$라운드의 바운드를 O(n/logn)으로 하는 것으로 이전까지 알려졌던 O(n)을 개선한 것이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.17-21
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• 2001

We proposed that concentrations of cartier electron as well as ionized donor defects in nonstoichiometric ZnO are proportional to $P^{-1/2}_{O_2}$, whenever they ionizes singly or doubly, by employing the Fermi-Dirac (FD) statistics for ionization of the native thermal defects $Zn_i$ and $V_o$. The effect of acceptor defect, zinc vacancy $V_{Zn}$made by the Frenkel and Schottky disorder reactions, on carrier concentrations was discussed. By application of the FD statistics law to their ionization while the formation of defects is assumed governed by the mass-action law, the calculation results indicate; 1. ZnO shows n-type conductivity with $N_D>$N_A$ and majority concentration of $n{\propto}\;P^{-1/2}_{O_2}$ in a range of $P_{O_2}$, lower than a critical value. 2. As the concentration of acceptor $V_{Zn}$ increases proportional to $P^{1/2}_{O_{2}}$, ZnO made at extremely high $P_{O_{2}}$, can have p-type conductivity with majority concentration of p ${\propto}\;P^{-1/2}_{O_{2}}$. One may not, however, obtain p-type ZnO if the pressure for $N_{D}<$N_{A}$ is too high.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1051-1056
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• 2014

Nitrous oxide ($N_2O$) is naturally generated from biological activity, such as bacteria's material exchange. However, recent $N_2O$ concentration in the atmosphere has being increased by the human activities such as industrial growth. One of factors to increase $N_2O$ concentration in the atmosphere is a $N_2O$ emission caused by the combustion of marine fuel oils. The marine transportation presently handles over 99 percent of the international freight cargoes and the number of ship is continuously increasing with increment of cargoes. In this study, author conducted a series of the experimental investigations on which combustion of fuels containing different element concentrations used in a 4-stroke marine diesel engine affect $N_2O$ emissions in the exhaust gas. Moreover, it is assessed on the extent to which fuel combustion patterns in the combustion chamber affect $N_2O$ emissions.

• Environmental Engineering Research
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• v.18 no.1
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• pp.21-28
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• 2013

In this study, the applicability of visible light-emitting-diodes (LEDs) to the photocatalytic degradation of indoor-level trichloroethylene (TCE) and perchloroethylene (PCE) over N-doped $TiO_2$ (N-$TiO_2$) was examined under a range of operational conditions. The N-$TiO_2$ photocatalyst was calcined at $650^{\circ}C$ (labeled N-650) showed the lowest degradation efficiencies for TCE and PCE, while the N-$TiO_2$ photocatalysts calcined at $350^{\circ}C$, $450^{\circ}C$, and $550^{\circ}C$ (labeled as N-350, N-450, and N-550, respectively) exhibited similar or slightly different degradation efficiencies to those of TCE and PCE. These results were supported by the X-ray diffraction patterns of N-350, N-450, N-550, and N-650. The respective average degradation efficiencies for TCE and PCE were 96% and 77% for the 8-W lamp/N-$TiO_2$ system, 32% and 20% for the violet LED/N-$TiO_2$ system, and ~0% and 4% for the blue LED/N-$TiO_2$ system. However, the normalized photocatalytic degradation efficiencies for TCE and PCE for the violet LED-irradiated N-$TiO_2$ system were higher than those from the 8-W fluorescent daylight lamp-irradiated N-$TiO_2$ system. Although the difference was not substantial, the degradation efficiencies exhibited a decreasing trend with increasing input concentrations. The degradation efficiencies for TCE and PCE decreased with increasing air flow rates. In general, the degradation efficiencies for both target compounds decreased as relative humidity increased. Consequently, it was indicated that violet LEDs can be utilized as energy-efficient light sources for the photocatalytic degradation of TCE and PCE, if operational conditions of N-$TiO_2$ photocatalytic system are optimized.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.789-800
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• 2013

$N_2O$ and $CH_4$, Greenhouse gas emission, Forest soil, Closed chamber technique, Soil uptake $N_2O$ and $CH_4$ are important greenhouse gases (GHG) along with $CO_2$ influencing greatly on climate change. Their soil emission rates are highly affected by bio-geo-chemical processes in C and N through the land-atmosphere interface. The forest ecosystems are generally considered to be net emission for $N_2O$; however, net sinks for $CH_4$ by soil uptake. Soil $N_2O$ and $CH_4$ emissions were measured at Mt. Taewha in Gwangju, Kyeonggi, Korea. Closed chamber technique was used for surface gas emissions from forest soil during period from May to October 2012. Gas emission measurement was conducted mostly on daytime (from 09:00 to 18:00 LST) during field experiment period (total 25 days). The gas samples collected from chamber for $N_2O$ and $CH_4$ were analyzed by gas chromatography. Soil parameters were also measured at the sampling plot. GHG averages emissions during the experimental period were $3.11{\pm}16.26{\mu}g m^{-2}hr^{-1}$ for $N_2O$, $-1.36{\pm}11.3{\mu}gm^{-2}hr^{-1}$ for $CH_4$, respectively. The results indicated that forest soil acted as a source of $N_2O$, while it acted like a sink of $CH_4$ on average. On monthly base, means of $N_2O$ and $CH_4$ flux during May (spring) were $8.38{\pm}48.7{\mu}gm^{-2}hr^{-1}$, and $-3.21{\pm}31.39{\mu}gm^{-2}hr^{-1}$, respectively. During August (summer) both GHG emissions were found to be positive (averages of $2.45{\pm}20.11{\mu}gm^{-2}hr^{-1}$ for $N_2O$ and $1.36{\pm}9.09{\mu}gm^{-2}hr^{-1}$ for $CH_4$); which they were generally released from soil. During September (fall) $N_2O$ and $CH_4$ soil uptakes were observed and their means were $-1.35{\pm}12.78{\mu}gm^{-2}hr^{-1}$ and $-2.56{\pm}11.73{\mu}gm^{-2}hr^{-1}$, respectively. $N_2O$ emission was relatively higher in spring rather than other seasons. This could be due to dry soil condition during spring experimental period. It seems that soil moisture and temperature mostly influence gas production and consumption, and then emission rate in subsoil environment. Other soil parameters like soil pH and chemical composition were also discussed with respect to GHG emissions.