• Journal of Korean Society for Atmospheric Environment
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• 제10권E호
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• pp.311-324
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• 1994

The quantitative knowledge of N $O_{\gamma}$ (＝N $O_{x}$ ＋HN $O_3$＋/PAN＋N $O_3$ ＋$N_2$ $O_{5}$ ＋HN $O_2$＋N $O_3$$^{-10}$ ＋organic nitrates＋......)distribution is essential in tropospheric chemistry, especially, especially that related to understanding the processes leading to ozone production. Ambient concentrations of NO, N $O_2$, HN $O_3$ and PAN as well as total N $O_{\gamma}$ were measured during June and early July 1992 at a rural site(Candor, NC), in the central Piedmont region of NC. The measurements of N $O_{\gamma}$ species were made in an effort to provide a comprehensive understanding of nitrogen chemistry and to investigate the total nitrogen budget at the site. N $O_{\gamma}$, N $O_2$, and NO showed diurnal variations with maxima in the morning. The maximum N $O_{\gamma}$ concentration reached was 14.5 ppbv, and the maximum concentrations of NO and N $O_2$ were 5.4 and 7.8 PPbv, respectively. The mean N $O_{\gamma}$ concentration as found to be 2.88$\pm$1.58 ppbv(n=743). The mean concentrations of NO and N $O_2$, were found to be 0.15 $\pm$ 0.29 ppbv(n＝785) and 1.31 $\pm$ 0.99 ppbv(n＝769). Products of photochemical oxidants, (N <$O_{\gamma}$-N $O_{x}$ ), such as HN $O_3$ and PAN, as well as ozone showed diurnal variation with maxima in the afternoon and minima at night The fractions of individual reactive nitrogen species to total N $O_{\gamma}$ were investigated and contrasted to the results from remote marine site and rural continental sites. N $O_{x}$ was the major species to total N $O_{\gamma}$(45%). NO concentrations appeared to be nearly constant whether the Prevailing winds were from continental areas or from oceanic areas. Linear regression of $O_3$ with (N $O_{\gamma}$- N $O_{x}$ )/N $O_{\gamma}$ (i.e. percent N $O_{x}$ converted to the photochemical products of N $O_{\gamma}$) yielded ( $O_3$) ＝25.8 〔 N $O_{\gamma}$-N $O_{x}$ 〕/(N $O_{\gamma}$) ＋27, ( $r^{2}$＝0.58). The regression intercept is interpreted as the ozone back ground (intercept=27ppbv) and the slope suggests that 8.6 molecules of ozone are formed per molecule of N $O_{x}$ oxidized products (when the average N $O_{\gamma}$ concentration, about 3 ppbv at the site, is used). The N $O_{x}$ N $O_{\gamma}$ ratio was used as an indicator of the chemical age of airmasses and the ratio showed strong positive correlations with HN $O_3$( $r^{2}$=0.58), PAN ( $r^{2}$=0.46) and $O_3$( $r^{2}$=0.62). Larger N $O_{\gamma}$ and N $O_{x}$ N $O_{\gamma}$ ratio were found when winds came from continental sides. It may suggest that synoptic meteorological conditions and transport of N $O_{x}$ are important in the distribution of N $O_{\gamma}$ and its relationship with photochemical oxidants at the site.

• 에너지공학
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• 제8권2호
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• pp.279-284
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• 1999

국내 무연탄의 질소 산화물과의 반응 특성을 알아보기 위하여 열중량분석기에서 등온 반응 실험을 행하였다. 사용 무연탄은 도계무연탄이며, 순수한 탄소인 SP-1 흑연이 비교 시료로 선택되었다. 탄소-NO 및 탄소-$N_2$O 반응은 55$0^{\circ}C$~90$0^{\circ}C$범위의 등온 조건과 기체 분압 5kPa~20 kPa조건에서 온도와 기체 분압의 영향을 실험하였다. NO 반응에서는 NO 분압에 대한 차수는 0.45~0.96 범위이었고, 활성화에너지는 39 kJ/mol~112 kJ/mol 범위의 값을 나타내었다. $N_2$O 반응에서는 $N_2$O 분압에 대한 차수는 0.62~0.87 범위이고, 활성화에너지는 190 kJ/mol~215.3 kJ/mol 범위의 값을 나타내었다. 무연탄 연소반응과 비교하면 $700^{\circ}C$ 이하에서는 $O_2$>NO>$N_2$O 순으로 반응속도가 변화하였고, $700^{\circ}C$ 이상에서는 $O_2$>$N_2$O>NO 순으로 반응속도가 빠르게 나타났다.

• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1781-1786
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• 2007

Two copper(II) complexes, [CuL3](ClO4)2 bearing one N-CH2CH2CONH2 group as well as one N-CH2CH2CN group and [CuL4](ClO4)2 bearing two N-CH2CH2CONH2 groups, have been prepared by the selective hydrolysis of [CuL2](ClO4)2 (L2 = C-meso-1,8-bis(cyanoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). The complex [CuL5](ClO4)2 bearing one N-CH2CH2C(=NH)OCH3 and one N-CH2CH2CN groups has been prepared as the major product from the reaction of [CuL2](ClO4)2 with methanol in the presence of triethylamine. In acidic aqueous solution, the N-CH2CH2C(=NH)OCH3 group of [CuL5](ClO4)2 undergoes hydrolysis to yield [CuL6](ClO4)2 bearing both N-CH2CH2COOCH3 and N-CH2CH2CN groups. The crystal structure of [CuL5](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2CH2C(=NH)OCH3 group) bond. The apical Cu-N bond distance (2.269(3) A) is ca. 0.06 A longer than the apical Cu-O (N-CH2CH2CONH2 group) bond of [CuL4](ClO4)2. The pendant amide group of [CuL3](ClO4)2 is involved in coordination. The carboxylic ester group of [CuL6](ClO4)2 is also coordinated to the metal ion in various solvents but is removed from the coordination sphere in the solid state.

• 한국세라믹학회지
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• 제31권9호
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• pp.995-1004
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• 1994

Phase relation and microwave dielectric properties of the system BaO.(Nd1-xSmx)2O3.TiO2 (n=4, 5) were studied. With n=5 (1 : 1 : 5), Ba2Ti9O20 and TiO2 formed in case of X$\leq$0.7, and Ba2Ti9O20 and Sm2Ti2O7 formed at X=1.0 as the second phases dispersed in fine-grained orthorhombic matrix phase. With n=4 (1 : 1 : 4). on the contrary, only fine grains of an ortho-rhombic phase were observed irrespective of Nd/Sm ratio. The compositions of these two stable orthorombic phases having distinct lattic constants even with the same Nd/Sm ratio were estimated as 4BaO.5(Nd1-xSmx)2O3.18TiO2 and BaO.(Nd1-xSmx)2O3.4TiO2 with n=5 and n=4 in the system BaO.(Nd1-xSmx)2O3.TiO2, respectively. Consequently the composition BaO.(Nd1-xSmx)2O3.5TiO2 lies in the compatible triangle of 4BaO.5(Nd1-xSmx)2O3.18TiO2 and the second phases mentioned above. The microwave dielectric properties (~4 GHz) of BaO.(Nd1-xSmx)2O3.5TiO2 can be controlled effectively by adjusting Sm content : with increasing X from 0 to 0.7, both dielectric constant and the temperature coefficient of resonant frequency decreased monotonically from 82 to 65 and from 91 (ppm/$^{\circ}C$) to -19(ppm/$^{\circ}C$), respectively, while unloaded Q(Qo) remained constant at about 2,600.

• 한국환경과학회지
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• 제16권8호
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• pp.913-920
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• 2007

Hydrochloride acid salts of new $N_2O_2$ tetradentate ligands containing amine and phenol N,N'-bis(2-hydroxybenzyl)-o-phenylenediamine(H-BHP), N,N'-bis(5-bromo-2-hydroxybenzyl)-o-phenylenediamine(Br-BHP), N,N'-bis(5-chloro-2-hydroxybenzyl)-o-phenylene-diamine(Cl-BHP), N,N'-bis(5-methyl-2-hydroxybenzyl)-o-phenylene-diamine (Me-BHP) and N,N'-bis(5-methoxy-2-hydroxybenzyl)-o-phenylenediamine(MeO-BHP) were synthesized. The ligands were characterized by elemental analysis, mass and NMR spectroscopy. The elemental analysis showed that the ligands were isolated as dihydrochloride salt. The potentiometry study revealed that the proton dissociation constants$(logK_n{^H})$ of ligands and stability constants $(logK_{ML})$ of transition and heavy metals complexes. The order of the stability constants of each metal ions for ligands was Br-BHP < Cl-BHP > H-BHP < MeO-BHP < Me-BHP.

• 한국환경과학회지
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• 제16권6호
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• pp.683-688
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• 2007

In this study, N doped $TiO_2$ (TiO-N) thin film was prepared by DC magnetron sputtering method to show the photocatalytic activity in a visible range. Various gases (Ar, $O_2\;and\;N_2$) were used and Ti target was impressed by 1.2 kW -5.8 kW power range. The hysteresis of TiO-N thin film as a function of discharge voltage wasn't observed in 1.2 and 2.9kW of applied power. Cross sections and surfaces of thin films by FE-SEM were tiny and dense particle sizes of both films with normal cylindrical structures. XRD pattern of $TiO_2$ and TiO-N thin films was appeared by only anatase peak. Red shift in UV-Vis adsorption spectra was investigated TiO-N thin film. Photoactivity was evaluated by removal rate measurement of suncion yellow among reactive dyes. The photodegradation rate of $TiO_2$ thin film on visible radiation was shown little efficiency but TiO-N was about 18%.

• 환경생물
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• 제37권3호
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• pp.309-316
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• 2019

농경지는 농업부문에서 발생하는 온실가스인 N₂O의 배출원이다. 따라서 농경지에서 N₂O를 줄일 수 연구가 필요하며, 본 연구에서는 농경지에 작물재배 시 무경운기술을 적용하고, 녹비작물로서 호밀과 헤어리배치를 각각 투입하여 N₂O 배출량 비교 평가하였다. 재배 기간 중 토양에 질소원이 공급된 초기에 배출량이 높았으며, 토양온도는 20~25℃, 수분함량은 20~30% 범위에서 N₂O 배출량이 높았다. 작물재배기간 동안 경운 유무와 투입된 질소원에 따른 처리구간 통계적 유의한 차이가 발생했다. 농경지 토양에서 배출되는 N₂O는 무경운을 통해 CF, HV 그리고 RY 처리구에서 각각 51.8%, 31.7% 그리고 59.6% 감축되었다. 또한 무경운 헤어리배치(HV-NT) 처리구에서 관행(CF-CT) 처리구 대비 59.0% N₂O 배출을 저감할 수 있었다. 헤어리배치를 투입함으로써 화학비료 사용량을 줄일 수 있고, 무경운을 통해 토양 교란을 방지하여 농경지 토양에서 배출되는 N₂O를 저감할 수 있었다. 이러한 감축기술에 대한 온실가스 저감효과를 평가하는 연구와 향후 온실가스 감축사업과 연계할 수 있도록 검인증 방법을 포함한 방법론 구축 등이 필요하다. 이후 농업분야 온실가스 감축사업인 배출권거래제 외부사업, 농업농촌 자발적 온실가스 감축사업, 저탄소농축산물 인증제 등과 연계하여 농업현장에서 활용할 수 있도록 해야 한다.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.225-238
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• 2021

옥수수(Zea mays)와 톨페스큐(Festuca arundinacea) 근권 토양을 접종원으로 사용하여 농화배양을 통해 CH₄ 산화컨소시움과 N₂O 환원 컨소시움을 얻었다. Illumina MiSeq 염기서열 분석법으로 접종원과 컨소시움의 세균 군집 특성을 비교하였고, 컨소시움의 CH₄ 산화와 N₂O 환원 활성에 미치는 뿌리삼출물의 영향을 규명하였다. 접종원이 다름에도 불구하고 옥수수와 톨페스큐 유래 CH₄ 산화 컨소시움 사이의 유사성이 높았고, 2종의 N₂O 환원 컨소시움도 서로 유사성이 높았다. 2종의 CH₄ 산화 컨소시움에서 우점도가 높은 metanotrophs는 Methylosarcina, Methylococcus 및 Methylocystis이었다. 2 종의 N₂O 환원 컨소시움에서 대표적인 N₂O 환원 세균은 Cloacibacterium, Azonexus 및 Klebsiella이었다. 옥수수 근권 유래 N₂O 환원 컨소시움의 N₂O 환원 속도는 옥수수 뿌리삼출물 첨가에 의해 1.6배, 톨페스큐 유래 컨소시움의 N₂O 환원 속도는 톨페스큐 뿌리삼출물 첨가에 의해 2.7배 향상되었다. 그러나 CH₄ 산화 컨소시움의 활성은 뿌리삼출물 첨가에 의해 향상되지 않았다. 본 연구의 옥수수 및 톨페스큐 근권 유래 CH₄ 산화 및 N₂O 환원 컨소시움은 유류 오염 정화과정에서 non-CO₂ 온실가스배출을 저감하는데 활용 가능하다.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2517-2522
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• 2012

New polynuclear poly(hexaaza macrocyclic) copper(II) complexes $[1](ClO_4)_{2n}{\cdot}(H_2O)_{2n}$, $[2](ClO_4)_{2n}{\cdot}(H_2O)_{2n}$, and $[3](ClO_4)_{2n}{\cdot}(H_2O)_{2n}$ have been prepared by the one-pot reaction of formaldehyde with ethylenediamine and 1,2-bis(2-aminoethoxy)ethane, 1,3-diaminopropane, or 1,6-diaminohexane in the presence of the metal ion. The polymer complexes contain fully saturated 14-membered hexaaza macrocyclic units (1,3,6,8,10,13-hexaazacyclotetradecane) that are linked by $N-(CH_2)_2-O-(CH_2)_2-O-(CH_2)_2-N$, $N-(CH_2)_3-N$, or $N-(CH_2)_6-N$ chains. The mononuclear complex $[Cu(H_2L^5)](ClO_4)_4$ ($H_2L^5$ = a protonated form of $L^5$) bearing two $N-(CH_2)_2-O-(CH_2)_2-O-(CH_2)_2-NH_2$ pendant arms has also been prepared by the metal-directed reaction of ethylenediamine, 1,2-bis(2-aminoethoxy)ethane, and formaldehyde. The polymer complexes were characterized employing elemental analyses, FT-IR and electronic absorption spectra, molar conductance, X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron micrograph (SEM). Electronic absorption spectra of the complexes show that each macrocyclic unit of them has square-planar coordination geometry with a 5-6-5-6 chelate ring sequence. The polymer complexes as well as $[Cu(H_2L^5)]^{4+}$ are quite stable even in concentrated $HClO_4$ solutions. Synthesis and characterization of the polynuclear and mononuclear copper(II) complexes are reported.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.357-360
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• 2011

플라즈마 원자층증착 방법을 이용하여 질소를 도핑한 산화아연 나노박막을 Si(111) 기판에 제조하였다. $Zn(C_{2}H_{5})_{2}$, $O_{2}$ 및 $N_{2}$을 사용하여 rf 파워 세기를 50-300 W로 변화시키면서 N-doped ZnO 박막을 제조하였다. 박막의 구조적 광학적 전기적 특성을 각각 XRD, PL, Hall 효과를 측정하여 분석하였다. 플라즈마 rf 파워가 증가함에 따라 ZnO 나노 박막 내의 질소(N) 함유 농도가 높아지고, p형 ZnO의 특성을 보였다.