• 센서학회지
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• 제16권6호
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• pp.434-440
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• 2007

Two kinds of new NOx sensing mechanism was proposed and examined. One of those was potentiomtric sensor based on the measurement of decomposed oxygen from NO using YSZ porous diffusion barrier and Pd catalytic electrode. The sensor based on decomposed oxygen measurement responded to the range of 300 - 1000 ppm NO in $N_{2}$ environment and the sensitivities were coincident with theoretical values at 700 and $800^{\circ}C$ but the decomposition rate depended on gas flow rate. The other sensor was equilibrium potentiometric type using $Gd_{2}O_{3}$-nitrates solid solution as sensing material. The sensor using $Gd_{2}O_{3}$-nitrates solid solution was suitable for NOxxsensing at $700^{\circ}C$ in 5 % oxygen and the sensitivity was 19.3 mV/decade. However, long term stability of the sensing material at high temperature was not sufficient.

• 한국결정성장학회지
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• 제9권5호
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• pp.480-485
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• 1999

FED용의 적색 형광체로 Al과 Pr이 첨가된 $SrTiO_3$의 제조와 형광특성에 대하여 연구하였다. 이 형광체는 metallic nitrates, ethylene glycol, citric acid를 출발물질로 하여 polymeric complex를 형성하는 Pechini 법으로 합성하였다. 본 실험에서 합성된 분말의 성장기구는 $900^{\circ}C$를 경계로 서로 다른 경향을 보이고 있으며, $600^{\circ}C$의 저온에서도 $SrTiO_3$상이 형성됨을 확인하였다. 또한 빛 발광특성의 경우는 Pr 이온에 의한 359 nm에서의 여기 스펙트럼과 저전압 음극선 발광의 경우 617 nm에서 최대 피크를 갖고 575 nm와 650 nm 사이에서 적색의 발광 스펙트럼이 관찰되었다. Pechini 법으로 합성된 $SrTiO_3$:Al, Pr 형광체의 경우 FED의 적색 형광체에 적용될 수 있을 것이다.

• Journal of Magnetics
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• 제18권3호
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• pp.230-234
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• 2013

The $Ni_{0.5}Zn_{0.5}Fe_2O_4$ nanoparticles about 30 nm were prepared using sol-gel method with metal nitrates dissolved in 2-methoxyathanol. The concentrations of the metal nitrates are adjusted from 0.1 to 0.75 M in order to study the influence on the structural and magnetic properties. The structure and morphology characterization revealed that the crystallinity was improved and the nanoparticle size was increased with the nutrition solution concentrations up to 0.5 M. Degraded crystallinity together with decreased nanoparticle size were observed for concentration of 0.75 M. The saturation magnetization at room temperature reached maximum at 0.5 M, which can be explained by considering the crystallinity and size effect.

• Ocean and Polar Research
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• 제27권3호
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• pp.251-263
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• 2005

In order to study changes in the marine ecosystem of the East China Sea derived by the global warming and construction of the Three Gorges Dam in the middle of the Changjiang, temperature, salinity, nutrients, and chlorophyll-a were studied intensively in the northern part of the East China Sea during the summer of 2003 and spring of 2004. According to the previous studies, the upwelling of the Kuroshio Current and the Changjiang resulted in a major inputs of nutrients in the East China Sea, but these two inputs may not contribute gently to a build up of nutrients in the northern East China Sea. In spring, relatively high concentrations of nitrates and phosphates were observed in the western part of the study area, which resulted from the supply of high concentrations of nutrients showing up in the surface waters as a result of vertical mixing from the ocean bottom. The concentrations of nitrates and phosphates observed in summer were lower than those in spring, since the surface waters were well stratified by the larger discharge of fresh water from the Changjiang in summer. The surface nitrate/phosphate ratios ranged from 1.3 to 16 in spring and from 1.1 to 15 in summer and were lower than the Redfield ratio of 16, indicating that the growth of phytoplankton is limited by nitrogen. This results are contrary to the previous results, in which the growth of phytoplankton was limited by phosphate in the East China Sea. The reason for this contrary result is that most nutrients in the surface waters are supplied by vertical mixing from the bottom waters with low nitrate/phosphate ratios, not directly influenced by the Changjiang with high nitrate/phosphate ratios. The depth-integrated chlorophyll observed in summer was similar to the previous results, but those measured in spring were almost twice as high as those found in previous results. The depth-integrated chlorophyll in spring was higher than that of summer, which results from high concentrations of nitrates and phosphates in the surface waters in spring due to active vertical mixing.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1247-1250
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• 2008

This presentation highlights work from the authors' laboratories on the various kinds of oxide optical materials, mainly luminescence and pigment materials with different forms (powder, core-shell structures, thin film and patterning) prepared by the Pechini-type sol-gel (PSG) process. The PSG process which uses the common metal salts (nitrates, acetates, chlorides etc) as precursors and citric acid (CA) as chelating ligands of metal ions and polyhydroxy alcohol (such as ethylene glycol or poly ethylene glycol) as cross-linking agent to form a polymeric resin on molecular level, allowing the preparation of many forms of luminescent materials.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 추계학술대회 논문집
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• pp.173-174
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• 2003

PAN은 1950년 중반 스모그 챔버연구원에서 'Compound X'라고 규정된 광화학 2차 오염물질로 강한 햇빛, NMHCs과 NOx의 존재하에서 이들 반응에 의해 형성된 물질이다 (Stephen, 1969) PAN은 눈을 자극하고, 식물에 대해 독성을 나타내며, 변이성과 발암을 유발할 가능성도 가지고 있다. 또한 PAN은 열적으로 불안정하여 상온에서 쉽게 NO2와 Peroxyaceyl radical로 분해 되며, 저온에서는 안정되게 존재하여 특히 상층 대류권을 통한NO2의 장거리 수송과 NO2의 reservoir역할을 한다. (중략)

• 공업화학
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• 제18권3호
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• pp.255-261
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• 2007

망간계 금속산화물을 이용한 저온 선택적 촉매 환원 반응에 대하여 연구하였다. 망간계 금속산화물은 $200^{\circ}C$ 이하의 저온에서 우수한 탈질 특성을 보인다. 온도에 따른 $NH_3/NOx$ 몰비 변화 실험을 통하여 미반응 암모니아의 배출은 몰비가 증가하고 온도가 감소할수록 증가하였으며, $NO_2$의 발생은 반대의 현상을 보였다. $NO_2$는 NO가 촉매 표면에 흡착된 후 nitrate종으로 산화되어 생성되는 것으로 보인다. 촉매 표면에 생성된 nitrate종과 흡착된 암모니아가 반응하기 때문에 $NH_3/NOx$ 몰비 1.0 이상에서도 미반응 암모니아의 배출이 없었다. 담지된 금속산화물의 영향은 Zr은 산화상태를 증가시켜 $NO_2$의 배출이 증가하였으며, Ce를 첨가시킨 경우 $NO_2$ 발생량이 감소하였다. 그러나 금속산화물의 첨가는 전체적으로 NOx 전환율을 감소시켰다

• 한국환경복원기술학회지
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• 제5권6호
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• Asian-Australasian Journal of Animal Sciences
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• 제26권11호
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• pp.1651-1658
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• 2013

Nitrate contamination in ground and surface water is an increasingly serious environmental problem and only a few bacterial strains have been identified that have the ability to remove nitrogen pollutants from wastewater under thermophilic conditions. We therefore isolated thermophilic facultative bacterial strains from wood chips that had been composted with swine manure under aerated high temperature conditions so as to identify strains with denitrifying ability. Nine different colonies were screened and 3 long rod-shaped bacterial strains designated as SG-01, SG-02, and SG-03 were selected. The strain SG-01 could be differentiated from SG-02 and SG-03 on the basis of the method that it used for sugar utilization. The 16S rRNA genes of this strain also had high sequence similarity with Geobacillus thermodenitrificans $465^T$ (99.6%). The optimal growth temperatures ($55^{\circ}C$), pH values (pH 7.0), and NaCl concentrations (1%) required for the growth of strain SG-01 were established. This strain reduced 1.18 mM nitrate and 1.45 mM nitrite in LB broth after 48 h of incubation. These results suggest that the G. thermodenitrificans SG-01 strain may be useful in the removal of nitrates and nitrites from wastewater generated as a result of livestock farming.

• 대한화학회지
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• 제31권5호
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• pp.419-424
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• 1987

메탄올, 에탄올, 아세토니트릴, 아세톤, THF 및 디옥산의 수용성 이성분 혼합용매계에서 MBN 및 BN의 가용매분해반응을 60$^{\circ}$C에서 속도론적으로 연구하였다. 반응속도는 비양성자성 혼합용매계에서 보다는 양성자성 혼합용매계에서 빠름을 알 수 있었으며, 이것은 양성자성 혼합용매계에 의한 수소결합효과가 전이상태를 안정화시키기 때문임을 알 수 있었다. 전이상태에 미치는 용매효과 및 벤질 치환기 효과등을 논의하기 위하여 Grunwald-Winstein 관계식, 확장된 Grunwald-Winstein 관계식 및 E$_T$(30)과 반응속도 상수사이의 관계식등을 적용하였으며, 결과로 부터 물함량이 많은 영역에서는 용매에 의한 electrophilic assistance가 크게 나타남을 알 수 있었다.