• Title/Summary/Keyword: Nitrous oxide

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MANAGEMENT OF ADULT DENTAL PHOBIC PATIENTS (성인 치과공포증 환자의 치료)

  • Kim, Dae-Eop
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.2
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    • pp.341-348
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    • 2007
  • We dentists perform many of routine dental procedures and must deal with much of the population's dental anxiety and fear. Dentists have used many non-pharmacological modalities initially to overcome anxiety and fear, including distraction, empathy, desensitization, and so on. However, certain patients need pharmacological backup of anxiety and fear to conquer dental treatment. This article presents four cases to introduce the methods from nitrous oxide and oxygen inhalation to general anesthesia for difficult adult dental phobic patients to deal with.

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N(2D) Product Velocity Mapped Imaging in the VUV Photolysis of Nitrous Oxide at 118.2 nm

  • Cosofret, Bogdan R.;Lambert, H. Mark;Houston, Paul L.
    • Bulletin of the Korean Chemical Society
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    • v.23 no.2
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    • pp.179-183
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    • 2002
  • Resonance-enhanced multiphoton ionization with time-of-flight product imaging of the $N(^2D)$ atoms has been used to study the $N_2O$ photodissociation at 118.2 nm and the two-photon dissociation at 268.9 nm. These imaging experiments allowed the determination of the total kinetic energy distribution of the $NO(X^2{\prod})$ and $N(^2D_{5/2})$ products. The $NO(X^2{\prod})$ fragments resulting from the photodissociation processes are produced in highly vibrationally excited states. The two-photon photodissociation process yields a broad $NO(X^2{\prod})$ vibrational energy distribution, while the 118.2 nm dissociation appears to produce a vibrational distribution sharply peaked at $NO(X^2{\prod},\;{\nu}=14)$.

Characteristics of Formaldehyde and N2O Formation from the Catalytic Reaction of Methane (메탄의 촉매반응에 의한 포름알데히드 및 N2O의 생성특성)

  • Choi, B.C.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.2
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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.

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Measurements of Nitrous Oxide Emission from Upland Agricultural Soil by a Closed Chamber System and Soil Controlling Factors (Closed chamber를 이용한 발 토양으로부터의 nitrous oxide 배출량 측정 및 토양인자들과의 상관성에 관한 연구)

  • 오진만;김득수
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.11a
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    • pp.170-172
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    • 2002
  • 현재 대기 조성의 변화는 과거(산업혁명 전)와는 달리 온실기체 증가(increasing the Green House Gas, CH$_4$, $CO_2$, $N_2$O) 및 기타 대기오염물질들(NOx, SOx, $O_3$등)의 조성증가로 인해 직.간접적으로 인간의 활동 및 건강에 영향을 끼치고 있다. 온실기체를 예를 들어, $CO_2$의 경우, 산업혁명 전과 비교하여 약 30%정도 증가하였으며, CH$_4$, $N_2$O는 각각 145%, 15%증가하였다(A.R Mosier 1998). (중략)

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Photodissociation of Nitrous Oxide by Slice Ion Imaging: The Stagnation Pressure Dependence

  • Cheong, Nu-Ri;Park, Hye-Sun;Nam, Sang-Hwan;Shin, Seung-Keun;Cho, Soo-Gyeong;Lee, Hai-Whang;Song, Jae-Kyu;Park, Seung-Min
    • Bulletin of the Korean Chemical Society
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    • v.30 no.11
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    • pp.2661-2664
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    • 2009
  • Photodissociation of nitrous oxide near 203 nm has been studied by a combination of high resolution slice ion imaging technique and (2+1) resonance-enhanced multiphoton ionization (REMPI) spectroscopy of $N_2(X^1{{\Sigma}_g}^+)$ via the (a″$^1{{\Sigma}_g}^+$) state. We have measured the recoil velocity and angular distributions of $N_2$ fragments by ion images of the state-resolved photofragments. The $N_2$ fragments were highly rotationally excited and the NN-O bond dissociation energy was determined to be 3.635 eV. Also, we investigated the photofragment images from the photodissociation of $N_2O$ clusters with various stagnation pressures.

INVESTIGATION OF EMISSION RATES OF AMMONIA, NITROUS OXIDE AND OTHER EXHAUST COMPOUNDS FROM ALTERNATIVE- FUEL VEHICLES USING A CHASSIS DYNAMOMETER

  • Huai, T.;Durbin, T.-D.;Rhee, S.-H.;Norbeck, J.-M.
    • International Journal of Automotive Technology
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    • v.4 no.1
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    • pp.9-19
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    • 2003
  • Exhaust emissions were characterized for a fleet of 10 alternative-fuel vehicles (AFVx) including 5 compressed natural gas (CNG) vehicles. 3 liquefied petroleum gas (LPG) vehicles and 2 85% methanol/15% California Phase 2 gasoline (M85) vehicles. In addition to the standard regulated emissions and detailed speciation of organic gas compounds, Fourier Transform Infrared Spectroscopy (FTIR) was used to measure ammonia (NH$_3$) and nitrous oxide ($N_2$O) emissions. NH$_3$, emissions averaged 0.124 g/mi for the vehicle fleet with a range from <0.004 to 0.540 g/mi. $N_2$O emissions averaged 0.022 g/mi over the vehicle fleet with range from <0.002 to 0.077 g/mi. Modal emissions showed that both NH$_3$, and $N_2$O emissions began during catalyst light-off and continued as the catalyst reached its operating temperature. $N_2$O emissions primarily were formed during the initial stages of catalyst light-off. Detailed speciation measurements showed that the principal component of the fuel was also the primary organic gas species found in the exhaust. In particular, methane, propane and methanol composed on average 93%, 79%, and 75% of the organic gas emissions, respectively, for the CNG, LPG. and M85 vehicles.

Nitrous Oxide Emissions from Red Pepper, Chinese Cabbage, and Potato Fields in Gangwon-do, Korea

  • Seo, Youngho;Kim, Gunyeob;Park, Kijin;Kim, Kyunghi;Jung, Yeong-Sang
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.6
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    • pp.463-468
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    • 2013
  • The level of nitrous oxide ($N_2O$), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic source, especially application of nitrogen fertilizers. Quantifying $N_2O$ emission from agricultural field is essential to develop national inventories of greenhouse gases (GHGs) emission. The objective of the study was to develop emission factor to estimate direct $N_2O$ emission from agricultural field in Gangwon-do, Korea by measuring $N_2O$ emissions from potato (Solanum tuberosum), red pepper (Capsicum annum L.), and Chinese cabbage (Brassica campestris L.) cultivation lands from 2009 to 2012. Accumulated $N_2O$ emission was $1.48{\pm}0.25kg$ $N_2O-N\;ha^{-1}$ for red pepper, $1.27{\pm}0.27kg$ $N_2O-N\;ha^{-1}$ for potato, $1.49{\pm}0.06kg$ $N_2O-N\;ha^{-1}$ for Chinese cabbage cultivated in spring, and $1.14{\pm}0.22kg$ $N_2O-N\;ha^{-1}$ for fall Chinese cabbage. Emission factor of $N_2O$ calculated from accumulated $N_2O$ emission, nitrogen fertilization rate, and background $N_2O$ emission was $0.0051{\pm}0.0016kg$ $N_2O-N\;ha^{-1}$ N for cropland in Gangwon province. More extensive study is deserved to be conducted to develop $N_2O$ emission factor for upland crops in Korea through examining the emission factors from various regions and crops because $N_2O$ emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

현장 Single Well Push-Pull 실험을 통한 탈질산화반응 각 단계의 반응속도 측정

  • Yeong, Kim;Jin Hun, Kim;Bong Ho, Son;Seong Uk, Eo
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.77-82
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    • 2004
  • Quantifying rates of microbial processes under subsurface conditions is difficult, and is most commonly approximated by laboratory studies using aquifer materials. In this study a single-well, 'push-pull' test method is adapted for the in situ determination of denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests at an experimental well field of Korea University. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifyinc microorganisms. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate '||'&'||'gt; nitrite '||'&'||'gt; nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibi1ity assessments for in situ denitrification in nitrate-contaminated aquifers.

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Reduction of Nitrous Oxide Emission by EGR Method on Diesel Engine (디젤엔진에서 배기가스 재순환 방법을 이용한 아산화질소의 배출률 저감)

  • Yoo, Dong-Hoon
    • Journal of Power System Engineering
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    • v.19 no.3
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    • pp.16-21
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    • 2015
  • Nitrous oxide($N_2O$) concentration in the atmosphere has been constantly increased by the human activities with industrial growth after the industrial revolution. One of factors to increase $N_2O$ concentration in the atmosphere is the $N_2O$ emission caused by the combustion of marine fuel. Especially, a sulfur component included in marine fuel oils is known as increasing the $N_2O$ formation in diesel combustion. Form this point of view, $N_2O$ emission from a ship is not negligible. On the other hand, Exhaust gas recirculation(EGR) that have thermal, chemical and dilution effect is effective method for reducing the NOx emission. In this study, an author investigated $N_2O$ reduction by using EGR on a direct injection diesel engine. The test engine was a 4-stroke diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of the engine was a fixed load of 75%. The experimental oil was a blend-fuel that were adjusted with sulfur ratio of 3.5%, and EGR ratio of 0%, 10%, 20% and 30%. In conclusion, diesel fuel that contained 3.5% sulfur component increased $SO_2$ emission in exhaust gas, and increment of EGR ratio reduced NO emission. Moreover, $N_2O$ emission was decreased as over 50% at EGR ratio of 10% and reduced 100% at EGR ratio of 30% compared with $N_2O$ emission of 0% EGR ratio.

Effect of Submucosal Midazolam on Percutaneous Saturation Percentage of Oxygen ($SpO_2$), End-tidal Carbon Dioxide ($EtCO_2$) and Physiologic Response When Combined with Chloral Hydrate, Hydroxyzine and Nitrous Oxide Sedation (구강 점막 하 주입 Midazolam과 경구 투여한 Chloral Hydrate의 용량에 따른 산소 포화도 및 생징후 변화에 대한 비교 연구)

  • Yu, Ji-Hye;Kim, Yun-Hee;Jung, Sang-Hyuk;Baek, Kwang-Woo
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.6 no.2 s.11
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    • pp.89-97
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    • 2006
  • Background: The aim of this study was to examine the difference of $SpO_2$, PR, $EtCO_2$, RR with submucosal injection of midazolam to oral chloral hydrate and hydroxyzine for pediatric patients Methods: Thirty two sedation cases were performed in this study. Patients were randomly classified into one group taking oral CH (60 mg/kg). hydroxyzine (1 mg/kg) and submucosal injection of midazolam (0.1 mg/kg) and the other group recieving oral CH (50 mg/kg), hydroxyzine (1 mg/kg) and submucosal injection of midazolam (0.2 mg/kg). For evaluating the depth of sedation. data including saturation percentage of oxygen ($SpO_2$), pulse rate (PR), end-tidal carbon dioxide ($EtCO_2$), respiratory rate (RR) and the behavior scale were checked every 2 minutes and were collected for only 40 minutes from the beginning of treatment and were analyzed using Two independent sample T-test. Results: Analysis showed no significant difference in the mean $SpO_2$, PR, $EtCO_2$, RR during sedation between two groups (P > 0.05). The values of $SpO_2$, PR, $EtCO_2$ and RR for both groups remained within the normal values. Conclusions: The results of this present study indicate that combination of oral CH, hydroxyzine, nitrous oxide gas inhalation and submucosal injection of midazolam improved the sedation quality without compromising safety.

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