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자발가압 성질을 가진 아산화질소의 2상유체 모델링을 통한 하이브리드 로켓 내탄도 해석 I
이정표(Jungpyo Lee),이선재(Sunjae Rhee),우경진(Kyoungjin Woo),오지성(Jisung Oh),정식항(Sikhang Jung),문희장(Heejang Moon),성홍계(Honggye Sung),김진곤(Jinkon Kim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11
자발가압 특성이 있는 N2O를 적용한 Blow-down 산화제 공급방식은 조절 시스템(Regulated system)에 비해 많은 장점을 가지고 있다. 그러나 탱크 내에 N2O가 액체와 기체의 2상으로 공존하고, 유동이 배출되는 동안 탱크 안의 N2O의 물성치가 계속적으로 달라지기 때문에 배출 유량을 예측하는데 어려움이 있다. 본 논문에서는 N2O를 적용한 Blow-down 산화제 공급방식을 간단하게 해석 할 수 있는 방법을 연구했다. 포화상태 N2O의 물성치는 NIST 데이터베이스를 이용했으며, 인젝터 모델로 nonhomogeneous nonequilibrium(NHNE) 모델을 적용하였다. 하이브리드 로켓 연소기를 이용해 cold flow test를 수행하였으며, 두 결과가 잘 일치함을 확인했다. The blow-down oxidizer feed system with self-pressurizing N2O has more advantages than the regulated system. However, it is difficult to predict the exhaust flow rate because there exist two phases in the N2O tank - liquid phase and gas phase, and the properties of N2O in storage tank are varied continuously during blow-down. In this paper, a method that can analyse simply the blow-down oxidizer feed system is studied. The properties of saturated N2O are found from the NIST data base, and mass flow through the orifice is modeled as NHNE. Cold flow test with hybrid rocket combustor is performed for the comparison where the results should found from the good agreement.
Zeng-hui Hu,Ying-bai Shen,Xiao-hua Su 한국식물학회 2009 Journal of Plant Biology Vol.52 No.4
Aldehydes, a group of volatile organic compounds (VOCs) often detected in the atmosphere, play a key role in atmospheric chemistry and plant resistance to stresses. We used gas chromatography/mass spectrometry to examine the volatiles of saturated aldehydes C6–C10 that were emitted from cuttings of ashleaf maple (Acer negundo L.) under varying levels of light intensity (80, 400, and 800 μmol m−2 s−1), O2 (2% and 50%), and CO2 (600, 1,000, and 1,200 ppm). An apparent, positive correlation was found between light intensity and emissions, and their release also was significantly enhanced by higher O2 concentrations. In contrast, emissions clearly were negatively correlated with CO2 levels. We speculate that the reactive oxygen species (ROS) generated during photosynthesis contribute to these elevated emissions. However, the mechanism for this ROS trigger is unknown.
Jun, Tae-Won,Woo, Jae-Hong,Kim, Yeon-Soo,Jeon, Byeong-Hwan,Kim, Kyeong-Lae,Park, Ik-Ryeul 한국체육무용국제교류학회 2002 한국체육무용국제교류학회지 Vol.8 No.-
The main purpose of this study is to find out how the oxygen supplement after an exercise in recovery period will affect partial pressure of respiratory gas, pH and lactic acid levels of blood. The subjects are 7 healthy amateur soccer players(25.40±2.54yrs). The experiments are divided into two parts, pre-test and the post-test. The subjects have 10 minutes of rest period after the first Grade Exercise Test(GXT), then the oxygen has been supplied during those 10 minutes before the second GXT. Gas analyzer has been used to analyze all the variables of gas analysis in blood such as HCO3-, pH, PO2, PCO2, O2 saturation(SaO2), and lactic acid analyzer has been used to analyze the blood lactic acid. The results are as followings. 1. Oxygen supplement during recovery period after GXTs, tend to increase PO2, SaO2 and PCO2 veinous blood. 2. Oxygen supplement at the beginning of recovery period after the second GXT, significantly effect on HCO3- and pH increase of veinous blood_ 3. Oxygen supplement after GXTs, decrease lactic acid level in blood during the recovery time. In conclusion, oxygen supplement after maximal exercise would be effective in recovery period after prolonged and intensive exercises that of oxygen supplement would lower HCO3-, pH levels, lactic acid levels after continuous GXT.
Incentive Spirometer를 이용한 심호흡이 시간경과에 따라 늑골골절 환자의 폐기능과 산소포화도에 미치는 영향
문대환(Daehwan Moon),김계하(Kye-Ha Kim),이석기(Seogki Lee) 한국콘텐츠학회 2015 한국콘텐츠학회논문지 Vol.15 No.3
본 연구의 목적은 Incentive Spirometer를 이용한 심호흡이 시간경과에 따라 늑골골절 환자의 폐기능과 산소포화도에 미치는 효과를 알아보는 것이다. 연구대상은 G시 소재 일개 병원에 입원한 늑골골절 환자 25명으로 대상자들에게 Incentive Spirometer를 이용한 심호흡이 교육되었다. 자료수집은 2013년 6월부터 10월까지로 폐기능과 산소포화도는 Micro spirometer와 pulse oximeter를 사용하여 입원 시와 중재 1일, 2일, 3일, 4일, 5일, 6일 후에 측정되었다. 자료는 SPSS (Statistical Package for the Social Science) 21.0 version program을 이용하여 기술분석 및 repeated measure ANOVA으로 분석되었다. Incentive Spirometer를 이용한 심호흡을 적용한 후의 폐기능과 산소포화도는 시간이 경과함에 따라 증가하였다. 따라서 늑골골절 환자에게 지속적으로 수행하는 Incentive Spirometer 심호흡이 권장될 필요가 있다. The purpose of this study was to examine the effects of deep breathing with Incentive Spirometer on pulmonary function and O2 saturation by time process in patients with rib fracture. The participants were 25 patients with rib fracture admitted to a hospital in G city. Deep breathing with Incentive Spirometer was educated for participants. Data were collected from June to October, 2013. Pulmonary function and O2 saturation were measured by using Micro spirometer and pulse oximeter at admission one day and 1day, 2day, 3day, 4day, 5day and 6day after applying intervention.. The collected data was analyzed by SPSS (Statistical Package for the Social Science) 21.0 version program with descriptive statistics, and repeated measure ANOVA. The level of pulmonary function and O2 saturation after applying deep breathing with incentive spirometer were increased as time went on. Therefore, patients with rib fracture should be suggested the continuous deep breathing with incentive spirometer.
Thermodynamic Evaluation of Oxygen Behavior in Ti Powder Deoxidized by Ca Reductant
Sun-Joong Kim,Jung-Min Oh,Jae-Won Lim 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.4
To produce low oxygen Ti powder of less than 1000 mass ppm, commercial Ti powder was deoxidized by two types of Ca reductants: a solid Ca and a Ca vapor. Compared with the iso-oxygen partial pressure in the Ti-O binary phase diagram, the PO2 in the raw Ti powder increased with temperature compared to the reduction reaction of Ca. Therefore, the O2 content in the Ti powder decreased as the deoxidation temperature increased from 873 K, showing a local minima at 1273 K. The oxygen concentration at 1373 K was greater than that at 1273 K because the oxygen solubility of the Ti powder was increased by the equilibrium relation between Ca and CaO. On the basis of the thermodynamic assessment, the deoxidation of Ti powder can be improved by increasing the temperature and lowering the oxygen solubility with the saturation of CaO.
Synthesis of Co:MgAl2O4 nano-powders for saturable absorber
Wang Chuanyun,Yang Wei,Wang Zhiqi,Liu Bina,Li Shihua,Lu Taoa,,Li Xueren,Miao Weipeng,Luo Wei 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2
Uniform Co:MgAl2O4 nano-powders for saturable absorber were prepared using inverse-drip co-precipitation method. Effectsof the precipitant and the metal ion solution on the composition and morphology of Co:MgAl2O4 nano-powders were studied. The results show that pure Co:MgAl2O4 nano-powders can be obtained, using the mixed solution of ammonium carbonate andammonia as the precipitant. The specific surface area of the particles reached 36 m2/g and the primary particle size was 39nm according to the SEM images and BET results.