• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.15.1-15.1
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• 2007

• 환경위생공학
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• 제12권1호
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• pp.25-37
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• 1997

The synthesis of high purity and ultra-fine $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ as precipitator was investigated to find an alternative process to solve various problems of present wet methods. This study consisted of two parts ; synthesis of $BaTiO_{3}$ precipitation with gaseous $NH_{3}$ and test of electrical property for the $La_{2}O_{3}$ doped $BaTiO_{3}$. The proper condition for the synthesis of $BaTiO_{3}$ by precipitation with gaseous $NH_{3}$ is as follows. The pH was 9.0. $H_{2}O_{2}$ mole ratio to $TiCl_{4}$ was 10. $NH_{3}$ gas follow rate did not influence the synthesis of $BaTiO_{3}$. The calcination temperature of $BaTiO_{3}$ was $300^{\circ}C$. Also, the synthesis of $La_{2}O_{3}$-doped $BaTiO_{3}$ was tested through the wet process. Under these condition, the shape of prepared $BaTiO_{3}$ powder was spherical type and the size of that was about $0.2{\mu}m$. After the powder was pressed, this green body was sintered at the $1300^{\circ}C$. Under these conditions, the water absorptance and the density of the obtained sintered body were below 0.04 %, 5.2 g/$cm^{3}$, respectively. Also the grain size of that was about $10{\mu}m$ and it was similar to commercial product.

• Asian-Australasian Journal of Animal Sciences
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• 제27권8호
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• pp.1211-1218
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• 2014

Higher concentrations of ammonia ($NH_3$) and carbon dioxide ($CO_2$) in animal barns can negatively affect production and health of animals and workers. This paper focuses on measurements of summer concentrations of ammonia ($NH_3$) and carbon dioxide ($CO_2$) in a naturally ventilated laying henhouse located at an egg production facility in Bursa region, western Turkey. Also, indoor and ambient environmental conditions such as temperature and relative humidity were measured simultaneously with pollutant gas concentrations. The average $NH_3$ concentrations during summer of 2013 was 8.05 ppm for exhaust and 5.42 ppm for inlet while average $CO_2$ concentration was 732 ppm for exhaust and 625 ppm for inlet throughout summer. The overall minimum, average and maximum values and humidity were obtained as $16.8^{\circ}C$, $24.72^{\circ}C$, and $34.71^{\circ}C$ for indoor temperature and 33.64%, 63.71%, and 86.18% for relative humidity. The lowest exhaust concentrations for $NH_3$ and $CO_2$ were 6.98 ppm and 609 ppm, respectively. They were measured in early morning at the maximum diurnal ventilation rate in July 2013 and August 2013. The highest concentrations were 10.58 ppm for $NH_3$ and 904 ppm for $CO_2$ recorded in the afternoon when the ventilation rate was the lowest in June 2013.

• Journal of Plant Biology
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• 제16권1_2호
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• pp.17-22
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• 1973

The experiments were conducted to examine the injuries of $SO_2$, $NH_3$, and $SO_2$ and NH3 mixed gas to the germination and the growth of plants. Six kinds of plants were used as the material. These plants seeds were treated with the gases for five days. Rate of the germination and the growth in height of varying plants were different according to the components of the gases. The critical concentration of the gases for both the germination and the growth were in 5ppm of $SO_2$, 50ppm of $NH_3$, and 50ppm $SO_2$ and 50ppm $NH_3$ mixed gases. When a low concentration of $SO_2$ was treated together with NH3, especially it was reduced to 60 percent of the damage in the germination and the growth. In the treatemnt with $SO_2$, the germination of the seeds which soaked in water for 24 hours reduced the injuries more 40 percent than those which for one hour. It was observed that the seeds with thick coasts or with originally intact coats were suffered but little damaged by the gases, and the external symptoms of an injury were shown, at first, in water pore, and then, in guard cell on the leaves.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.154-158
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• 2001

The steps for the generation of very thin GaN films on ultrathin AlN/6H-SiC surface by alternating a pulsative supply (APS) of trimethyl gallium and NH3 gases have been examined by ASED-MO calculations. We postulate that the gallium cul ster was formed with the evaporation of CH4 gases via the decomposition of trimethyl gallium (TMG), dimethyl gallium (DMG), and monomethyl galluim (MMG). During the injection of NH3 gas into the reactor, the atomic hydrogens were produced from the thermal decomposition of NH3 molecule. These hydrogen gases activated the Ga-C bond cleavage. An energetically stable GaN nucleation site was formed via nitrogen incorporation into the layer of gallium cluster. The nitrogen atoms produced from the thermal degradation of NH3 were expected to incorporate into the edge of the gallium cluster since the galliums bind weakly to each other (0.19 eV). The structure was stabilized by 2.08 eV, as an adsorbed N atom incorporated into a tetrahedral site of the Ga cluster. This suggests that the adhesion of the initial layer can be reinforced by the incorporation of nitrogen atom through the formation of large grain boundary GaN crystals at the early stage of GaN film growth.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.158.2-158
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• 2002

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2003년도 하계학술대회 논문집
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• pp.141-141
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• 2003

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.294-295
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• 2003

삶의 질이 높아감에 따라 환경에 대한 사람들의 관심이 늘어가고 있다. 그중 미소량으로도 인체에 치명적인 해를 주는 유기인 화합물에 대한 실시간 모니터링 기술이 요구되고 있다. 이를 검출할 수 있는 센서로서 광학식 센서는 기존의 센서(반도체식, 전기화학식 등)에 비하여 선택성과 반응전후의 복귀성 및 온·습도의 영향 등의 문제를 개선할 수 있다. 기존의 광학식 센서는 원적외선 영역을 이용하는데 이는 광학식 센서의 경우 높은 감도를 보이나 이들 시스템은 냉각장치를 요구하며 장비의 가격이 고가인 단점이 있다. (중략)

• 한국토양비료학회지
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• 제20권1호
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• pp.55-61
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• 1987

담수상태(湛水狀態)의 논토양중(土壤中) 유기물함량(有機物含量), 온도(溫度), pH 질소비종(窒素肥種) 및 시비량등(施肥量等)을 달리했을때 탈질작용(脫窒作用)과 탈질량(脫窒量)을 알고저 질내(窒內)에서 항온시험(恒溫試驗)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 담수상태(湛水狀態)의 논토양(土壤)에서 탈질량(脫窒量)에 관계(關係)가 큰 요인(要因)은 토양유기물함량(土壤有機物含量) > 항온온도(恒溫溫度) > pH가(價) > 질소비종(窒素肥種) > 질소시비량(窒素施肥量)의 순(順)으로 컸다. 2. $N_2O$ gas의 생성량(生成量)은 토양유기물함량(土壤有機物含量) 3.0%인 토양(土壤)에서 항온온도(恒溫溫度) $20^{\circ}C$, pH 6.0일때 $KNO_3$ 20mg/100 토양(土壤) 시용구(施用區)에서 가장 많았다. 3. $N_2O$ gas 1 mole 생성(生成)하는데 소모(消耗)되는 탄소(炭素)는 전체평균(全體平均)이 0.5 mole 이였으며 탄소량(炭素量)이 제일(第一) 많이 요구(要求)되는 경우는 토양유기물함량(土壤有機物含量) 1.0%인 토양(土壤)에서 류안(硫安) 10mg/100g 토양(土壤) 시용시(施用時)(1.06 mole)였으며 제일(第一)적은 탄소요구(炭素要求)의 경우는 유기물함량(有機物含量) 3.0%인 토양(土壤)에서 $KNO_3$ 20mg/100g 토양(土壤) 시용시(施用時)(0.13 mole)였다. 4. Michealis-Menten의 효소반응식(酵素反應式)에서 유도(誘導)된 $N_2O$ gas의 V/2가(價)는 유기물(有機物) 1.0% 토양(土壤)에서 $(NH_2)_2CO$ 시용시(施用時) 550, $KNO_3$ 시용시(施用時)는 $1100N_2O{\mu}g/100g$ 토양(土壤)이였고 3.0%인 토양(土壤)에서 $(NH_4)_2SO_4$ 시용시(施用時)는 $490N_2O{\mu}g/100g$ 토양(土壤)이였으며 $KNO_3$ 시용시(施用時)는 시비량(施肥量)이 증가(增加)할수록 V/2가(價)는 계속 증가(增加)되었다.

• 한국환경과학회지
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• 제22권11호
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• pp.1481-1498
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• 2013

The SCR (selective catalytic reduction) system is highly-effective technique for NOx reduction from exhaust gases. In this study, the effects of the direction and size of nozzle and the ammonia injection concentration on the performance of SCR system are analyzed by using the computational fluid dynamics method. When the nozzle is arranged in zigzaged direction which is normal to exhausted gas flow, it is shown that the uniformity of gas flow and the NH3/NO molar ratio is improved remarkably. With the change of the ammonia injection concentration from 0.2 vol%(wet) to 1.0 vol%(wet), the uniformity of gas flow shows a good results. As the size of nozzle diameter changes from 6 mm to 12 mm, the uniformity of gas flow is maintained well. It is shown that the uniformity of the $NH_3/NO$ molar ratio becomes better with decreasing the ammonia injection concentration and the size of nozzle diameter.