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아파트 실내 환경에서 실시간 측정시스템을 활용한 HONO 농도 측정 및 생성기작 연구
박승식(Seung Shik Park),홍진의(Jin H. Hong),이재훈(Jai H. Lee),김영준(Young J. Kim),조성용(Sung Y. Cho),김승재(Seung J. Kim) 한국대기환경학회 2008 한국대기환경학회지 Vol.24 No.1
Nitrous acid (HONO) can be produced by heterogenous reactions of nitrogen dioxide on surface materials and direct emission from combustion sources. However, a little is known of indoor HONO levels or the relationship between residential HONO, NO, and NO₂ concentrations in occupied houses. Therefore, we measured simultaneously NO, NO2, and HONO concentrations in living room of an apartment using continuous analyzers to study the production of HONO (June 22~30, 2006). The 4-min average concentrations of indoor NO, NO₂, and HONO were 4.3 (range: 0.4~214.3), 10.3 (2.0~87.3), and 1.8 ppb (0.3~7.7), respectively. Peak levels of HONO up to 7.7 ppb and 24-hr averages as high as 1.7 ppb were measured. In agreement with previous studies, indoor HONO concentrations increased during operation of an unvented gas range. Examination of the observed kinetics suggests that the secondary production of indoor HONO, possibly as a result of heterogeneous reactions involving NO₂ and H₂O is associated with [NO₂]²[H₂O] (r²=0.88) rather than with [NO][NO₂][H₂O] (r²=0.75). Three combustion experiments at nighttime were also carried out to investigate the effects of vented combustion on the HONO, NO, and NO₂ concentrations. It was found to release HONO for 10~15 minutes after NO and NO₂ source was turned off, and peak values were finally attained. Compared to unvented combustion, peak NO₂ and HONO concentrations were 3.2 and 2.0 times lower at weak vented combustion (air flow: 340㎥/hr) and 4.9 and 2.4 times lower at strong vented combustion (air flow: 540 ㎥/hr), respectively, emphasizing importance of operating ventilation hood fan during combustion to improve indoor air quality.
이재훈(J. Lee),권장혁(J.H. Kwon) 한국전산유체공학회 2008 한국전산유체공학회지 Vol.13 No.1
The fluid-structure interaction analysis such as a static aeroelastic analysis requires the result of each analysis as an input to the other analysis. Usually the grids for the fluid analysis and the structural analysis are different. so the results should be transformed properly for each other. The Infinite Plate Spline(IPS) and the Thin Plate Spline(TPS) are used in interpolating the displacement and the pressure. In this study, such interpolation methods are compared with kriging which provides a precise response surface. The static aeroelastic analysis is performed for the supersonic flow field with shock waves and the pressure field is interpolated by the TPS and kriging. The TPS shows tendency to weaken the shock strength, whereas kriging preserves the shock strength.
천이 SST 난류 모델을 이용한 3차원 날개 공력 해석
이재훈(J. H. Lee),정경진(K. J. Jung) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
In this study, aerodynamic coefficients are computed with the transition SST turbulence model for a three-dimensional wing. The transition SST turbulence model solves two additional transport equations to reflect the effect of the transition. Using this model, the three-dimensional wing of an aerial vehicle is solved, and their results are compared with other turbulence model. According to the numerical tests, the transition SST model predicts lower viscous drag which is resulted from the transition. Therefore, this model will be useful in the design of airfoils and wings in the transitional flow.
이재훈(J.H. Lee),이수강(S.G. Lee),이병주(B.J. Yi),이석희(S.H. Lee),이정헌(J.H. Lee),김희국(W.K. Kim) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월
In this study, a spatial 3-dof haptic mechanism is implemented. The implemented mechanism does not employ the gear transmissions as velocity reducers for all three joints but uses wire-based transmissions, thereby it is able to minimize the frictions significantly. Also, by employing the structure of the four-bar mechanism to drive third joint from close to the base, the mechanism is able to minimize the inertia effect from the third actuator very effectively. Its kinematic analysis such as position and velocity analyses are performed first. Then, its operating software development, hardware implementation, and the related interfaces between a PC and the implemented Haptic device are completed. To evaluate its potential and its performance as a haptic device, a experiment generating a virtual constraint in a operational task space is conducted and preliminary results are discussed.