• 대한치과마취과학회지
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• 제2권1호
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• pp.1-6
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• 2002

The usage of nitrous oxide is increased for the anxious patient to dental treatment. There are two methods to induce the sedation during dental treatment. One is sedation with drugs the other no need of drugs. We discussed here about sedation with drugs. The methods of drug administration are oral, intramuscular, intravenous, inhalation. The method of oral administration of drugs are convenient to patient and doctor but poor controllability. Intramuscular method is a parenteral technique that maintains several advantages over the enteral technique. However its pales in comparison to other parenteral technique. Intravenous method represents most effective method of ensuring predictable and adequate sedation in all patients. But it has inability to reverse the action of drugs after they have been injected except some drugs (e.g., narcotics and benzodiazepine). A variety of gaseous agents may be administered by inhalation to produce sedation. In dental practice, the inhalation administration of gas means use of nitrous oxide. There are many advantages of nitrous oxide administration. First, very short latent period and rapid onset of drug action which lead to possible titration of drug concentration. With nitrous oxide, clinical effects may become noticeable as quickly as 15 to 30 seconds after inhalation. Recovery from inhalation sedation is also quite rapid. In out patient dental practice rapid recovery is very important because it permit to discharge the patient without escort and the patient return to their ordinary life without limit. To success the conscious sedation with nitrous oxide, the administrator should be keep the mind that always titration of nitrous oxide concentration during induction and treatment. Careful observation need during treatment to prevent oversedation because the adequate nitrous oxide concentration to patients changed by environmental stress. Always begins with 100% oxygen and ends with 100% oxygen to prevent diffusion hypoxia which rare in clinical practice.

• 대한소아치과학회지
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• 제30권1호
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• pp.124-131
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• 2003

최근 치과영역에서 아산화질소(Nitrous Oxide)를 이용한 의식하 진정과 필은 진정의 임상 적용이 증가함에 따라 수술실 또는 진료실 환경이 아산화질소로 오염될 수 있다. 비록 낮은 농도일지라도 장기간 아산화질소에 노출 시 자연유산의 증가, 기형아 출산 증가, 말초신경염 및 운동신경 장애 등과 같은 부작용을 초래하는 것으로 알려져 있다. 호흡시 흡입 공기의 구성성분의 변화를 줄 수 있는 구강 입구로부터 반경 12 inch 이내 영역인 호흡대역(Breathing zone)에서 아산화질소 농도는 치료자에게 영향을 주게된다. 소아 환자에게 주로 적용되는 깊은 진정시는 환자의 구호흡양에 따라서 호흡대역에서 아산화질소의 농도에 영향을 주게되므로, 깊은 진정시 구호흡의 증가 원인을 규명하기 위해 잉여가스 배출 방법을 달리하여 호흡대역에서 아산화질소 농도를 측정 비교하여 다음과 같은 결론을 얻었다. 1. 깊은 진정을 시행하는 경우 호흡대역에서 아산화질소의 농도는 공급 가스량 증가에 의한 비기도 저항 증가에 따라 증가하는 양상을 보였다. 호흡대역에서 아산화질소 농도 증가는 구호흡 증가에 의한 것이며 구호흡은 비기도 저항과 관계가 있다 할 수 있다. 즉 비기도 저항 증가는 구호흡의 한 요인이라 할 수 있다. 음압을 사용한 호기가스 배출장치를 사용하여도 NIOSH에서 권장하는 허용치에는 미치지 못하였고 이를 위해서는 팬이나 다른 제거 장치가 함께 사용되어야 한다. 2. 구강편도의 크기는 기도 저항이 적은 경우 즉 음압을 사용하여 호기가스 제거하는 경우 구호흡에 영향을 주었다.

• 한국환경농학회지
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• 제39권3호
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• pp.237-245
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from upland fields. This method has the advantages of being simple, easily available and economical. However, uncertainty estimation is essential for accurate assessment of greenhouse gas emissions and verification of emission reductions. The nitrous oxide emissions from upland field is very important for the nitrogen budget in the agriculture sectors. Although assessment of uncertainty components affecting nitrous oxide emission from upland field is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. This study aims at elucidation of influencing factors on measurement uncertainty of nitrous oxide concentrations measured by an automated open closed chamber method from upland field. METHODS AND RESULTS: The nitrous oxide sampling system is located in the upland field in Gyeonggi-do Agricultural Research and Extension Services (37°13'22"N, 127°02'22"E). The primary measurement uncertainty components influencing nitrous oxide concentrations (influencing factors) investigated in this research are repeatability, reproducibility and calibration in the aspects of nitrous oxide sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor are quantified and compared. CONCLUSION: Results of this study show what influencing factors are more important in determination of nitrous oxide concentrations measured using the automated open closed chambers located in the monitoring site. Quantifying the measurement uncertainty of the nitrous oxide concentrations in this study would contribute to improving measurement quality of nitrous oxide fluxes.

• 한국기후변화학회지
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• 제7권4호
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• pp.427-432
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• 2016

Nitrous oxide is one of the main sources of greenhouse gases and its concentration has increased from 273 ppb in 1,750 to 315 ppb in 2005. Specially, nitrogen fertilizer used in agricultural soils is considered as an important source of atmospheric $N_2O$ emission. This study was conducted to estimate the difference of nitrous oxide emission as chamber position on furrow and ridge and crop existence in gas sampling chamber on upland. Four treatments used in this experiment were (1) no-fertilizer without crop in chamber on ridge, (2) fertilizer application without crop in chamber on ridge, (3) fertilizer application with crop in chamber on ridge, (4) fertilizer application without crop in chamber on ridge and furrow. Nitrous oxide emission at fertilizer application with crop in chamber on ridge were the highest while were the lowest at no-fertilizer without crop in chamber on ridge. There was no significant difference of nitrous oxide emission by chamber position, but total emission by crop existence in chamber was significant difference. Therefore, in order to estimate greenhouse gases emission using chamber method in upland, it should be considered in correlation with crop existence in chamber and characteristic changes like as the soil moisture, microbial flora by crop growth stage.

• 동력기계공학회지
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• 제18권6호
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• pp.106-112
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• 2014

The diesel engine, which has high compression ratio than other heat engines, has been using as the main power source of marine transport. Especially, since marine diesel engines offer better specific fuel consumption (SFC), it is environment-friendly compared to those used in other industries. However, attentio should be focused on emissions such as nitrous oxide ($N_2O$) which is generated from combustion of low-grade fuels. Because $N_2O$ in the atmosphere is very stable, the global warming potential (GWP) of $N_2O$ is 310 times as large as that of $CO_2$, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. It has been hitherto noted on the $N_2O$ exhaust characteristics from stationary power plants and land transportations, but reports on $N_2O$ emission from the marine diesel engine are very limited. In this experimental study, a author investigated $N_2O$ emission characteristics by using changed diesel fuel components of nitrogen and sulfur concentration, assessed on the factors which affect $N_2O$ generation in combustion. The experimental results showed that $N_2O$ emission exhibited increasement with increasing of sulfur concentration in fuel. However, all kinds of nitrogen component additives used in experiment could not change $N_2O$ emission.

• 한국수자원학회논문집
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• 제42권8호
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• pp.631-641
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• 2009

본 연구는 부영양화되어 있는 하구감조역에서의 $N_2O$생성과 거동을 파악하는 것을 목적으로 도시역에서의 N2O발생에 착안하여 그 중에서도 인위적 임팩트가 크다고 판단되는 하수처리수 생활폐수 등이 유입되는 도시하천감조역을 대상으로 현지 정점조사를 실시하여 수역의 사계절에 걸친 각 질소성분의 농도변화와 flux를 상세히 파악하고 저질간극수 중의 연직분포를 측정하였다. 그 결과, 완혼합이고 염수쐐기설(楔)가 형성되는 Tatara천(川)에서 하수처리수는 해수의 혼합형태의 영향을 크게 받고 고농도수괴(水塊)로서 표층을 이동하고 있으며, 이 수역의 질소변환기구 및 $N_2O$생성과정에 큰 영향을 미치고 있는 것이 밝혀졌다. 이 수역에서 관측된 $N_2O$농도는 1.8-20.9 $\mu M$로서 대기중의 포화농도와 담수중의 포화농도를 고려하면 항상 포화농도상태이며, 주발생원은 수역저토였다. 저질간극수 중의 각 질소성분의 농도분포는 호소와 인근해역에서의 분포와는 달리 분자확산 이외의 수송경로가 있다는 것이 시사되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1051-1056
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• 2014

아산화질소($N_2O$, Nitrous Oxide)는 박테리아의 물질대사와 같은 생물학적인 활동에 의하여 자연적으로 발생한다. 하지만, 최근의 대기 중 $N_2O$는 산업의 성장과 같은 인간의 활동에 의하여 증가되어져 왔다. 이 중에 대기 중의 $N_2O$농도를 증가시키는 요인들 중에 하나는 선박용 연료 연소로부터 발생하는 $N_2O$이다. 현재 해상 운송은 국제 물류의 99퍼센트 이상을 담당하고 있고, 선박척수는 물동량의 증가와 함께 증가하고 있다. 따라서, 본 연구에서는 4-행정 선박용 디젤엔진을 사용하여 다른 성분 농도들을 포함하는 연료의 연소가 $N_2O$ 배출률에 미치는 영향에 대하여 실험적인 조사를 실시하였다. 또한, 연소실 내의 연료 연소 패턴이 $N_2O$ 배출률에 미치는 영향에 대하여 평가하였다.

• 한국기후변화학회지
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• 제8권1호
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• pp.31-39
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• 2017

The emission quantity of nitrous oxide is second largest among non-$CO_2$ greenhouse gas in Korea. In this study, we investigated loss rate of nitrous oxide which was filled in PVF and Al-PE bag as time goes on. Concentrations of tested samples were about 25 ppmv, 50 ppmv, 75 ppmv prepared by standard reference gas. In case of all experiments, loss rate of PVF bag was higher than Al-PE bag. After 18 days, loss rate of PVF bag was from 29.7% to 38.6% while Al-PE bag was from 21.7% to 23.7%. Especially the differential growed bigger when initial concentration of $N_2O$ in PVF bag was lower. And we also studied the effect of cock opening/closing procedures on loss rate. Prepared samples in experimental group were analyzed several times for 20 days and samples in control group were analysed only 1 time after 20 days. The experimental results showed that cock opening/closing procedures appeared to have little impact on loss rate.

• 한국자동차공학회논문집
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• 제3권2호
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• pp.95-101
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• 1995

Experiments have been conducted to investigate the characteristics of formaldehyde and nitrous oxide formation from the catalytic reaction of methane. Catalysts used in the experiment were Pd. Pd/Pt/Rh loaded on ${\gamma}-Al_2O_3$ and ${\gamma}-Al_2O_3-La_2O_3$ monolith. In the catalytic reaction of methane. as the concentration of NO, $O_2$ and $CH_4$ increased, the formaldehyde emission was increased. The concentration of $N_2O$ increased as NO and CO increased. It was also found that the formaldehyde emission was produced by the gas reaction of methane in high temperature above 950K.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.99-105
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• 2013

In this study, nitrous oxide ($N_2O$) emission was compared between the operations of two different sequencing batch reactors, conventional sequencing batch reactor (CNVSBR) and simultaneous nitrification and denitrification sequencing batch reactor (SND-SBR), using synthetic wastewater. The CNV-SBR consisted of anoxic (denitrification) and aerobic phases, whereas the SND-SBR consisted of a microaerobic (low dissolved oxygen concentration) phase, which was achieved by intermittent aeration for simultaneous nitrification and denitrification. The CNV-SBR emitted 3.9 mg of $N_2O$-N in the denitrification phase and 1.6 mg of $N_2O$-N in the nitrification phase, resulting in a total emission of 5.5mg from 432mg of $NH_4^+$-N input. In contrast, the SND-SBR emitted 26.2mg of $N_2O$-N under the microaerobic condition, which was about 5 times higher than the emission obtained with the CNV-SBR at the same $NH_4^+$-N input. From the $N_2O$ yield based on $NH_4^+$-N input, the microaerobic condition produced the highest yield (6.1%), followed by the anoxic (0.9%) and aerobic (0.4%) conditions. It is thought that an appropriate dissolved oxygen level is critical for reducing $N_2O$ emission during nitrification and denitrification at wastewater treatment plants.