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OPC(광합성 입자 계수기)로 측정한 2001년 서울지역 에어로졸의 입경 분포
정찬훈,전영신,최병철 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.5
The characteristics of one year observation aerosol data in Seoul, 2001 was studied using and OPC(Optical Particle Counter). The size resolved aerosol number concentrations of 0.3∼25㎛ were measured. The results were compared with PM_(10) mass concentration data under various meteorological conditions including dust and precipitation events. For fine particles whose diameter is less than 2.23㎛, the number concentration increases in the early morning which is considered due to transportation, while the coarse mode particles increase during daytime. This increase can be explained as local sources and human activities near sampling site. Hourly averaged data show that there exists diurnal variation. Generally, PM_(10) data showed a similar tendency with OPC data. The size resolved OPC data showed that the particles of 0.5∼3.67㎛ are positively correlated with PM_(10) data. The accumulated volume fraction of size resolved aerosol concentration in 0.5∼10㎛ showed that 0.5∼2.23㎛ particles occupied 59.2% of total aerosol volume of 0.5∼10㎛.
A High Precision Aeroelastic Analysis of an Air Vehicle with High-Aspect-Ratio Wings
정찬훈,Anas El Arras,신상준,조창민,장세용,김상용 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4
Aeroelastic analysis of an aircraft with a high aspect ratio-wing for medium altitude and long endurance capability was attempted in this paper. In order to achieve such objective, various structural and aerodynamic models were adopted. The traditional approach has been based on an Euler-Bernoulli beam structural model. In addition to that, a geometrically non-linear beam model was adopted. The structural analysis results of the present beam models were obtained and compared with those by three-dimensional NASTRAN finite element model. The relevant unsteady aerodynamic forces were acquired by two methods. First, a finite state dynamic inflow unsteady aerodynamics model was developed and evaluated. Second, ZAERO, which is based on the doublet lattice method, was used. These two kinds of aerodynamic forces were compared, and applied to the foregoing flutter analysis. The structural mode shapes and natural frequencies from both the Euler-Bernoulli beam structural model and the three-dimensional finite element model were transferred to ZAERO, which used the DLM aerodynamics to estimate the flutter. Similarly, flutter prediction was conducted by combining the Euler-Bernoulli beam structural model and the finite state dynamic inflow unsteady aerodynamics. The next phase of the present research will deal with the analysis of the possible interaction between the rigid-body degrees of freedom and the aeroelastic modes.
지역특성과 산정식 변화를 고려한 시군단위 축산부문 온실가스 배출량 분석
정찬훈,박진선,이종식,김건엽,정현철,서교,Jung, Chan Hoon,Park, Jin Seon,Lee, Jong Sik,Kim, Gun Yeop,Jeong, Hyeon Cheol,Suh, Kyo 한국농공학회 2017 한국농공학회논문집 Vol.59 No.4
The equations and emission factors for estimating national GHGs are developed based on IPCC guidelines. The GHGs on livestock sector has been calculated using methodologies following 1996 IPCC guideline in South Korea although 2006 IPCC guideline was announced in 2006. The purpose of this study is to understand the implications of guideline updates for national GHGs changes in the livestock sector and analyze the effect of regional major livestock characteristics using KOSTAT time series data (1990 ~ 2014). The results show a new guideline makes GHGs reduce in the livestock sector up to 11 % with subdivided emission factors and the livestock characteristics affect regional GHGs. Gyeonggi-do, the top emitter among 16 states, records 784 thousand tons $CO_2eq.$ and Daejeon has the highest potential (82 %) of GHGs reduction. Swine is the most contributor for regional GHGs except Seoul and Gwangju, but the share of GHGs for chickens is less than 12 % in spite of the largest livestock population (87 %).
정찬훈,신형섭 한국초전도.저온공학회 2018 한국초전도저온공학회논문지 Vol.20 No.3
No-insulation (NI) pancake magnets are fabricated using Rare earth-Barium-Copper Oxide (REBCO) coated conductor (CC) tapes, which enabled a very compact magnet in the aspects of high critical current density (Jc) and high mechanical strength by removing insulation and allowing thinner stabilizer. They have also advantages such as self-quench protection. Therefore, it does not need quench detection and protection that can be very challenging in a high critical temperature (Tc) superconducting magnet technology. Recently, it was reported that the NI REBCO CC magnets have some drawbacks of long charging time and high field ramp loss which will be a concern in the operation of cryocooled magnets. These issues are related to the turn-to-turn contact resistivity and can be released by managing it. This is also closely related to the activity of reducing the contact joint resistance in the case of CC joints for long length CC fabrication. Therefore, in this study, the turn-to-turn contact resistance (Rc) at the CC contact part of differently stabilized CC tapes was measured. The behaviors of Rc at CC contact parts according to the applied contact pressure were investigated. The range of Rc measured for CC tapes adopted will provide fundamental data for design and fabrication of the CC NI coils.
정찬훈,신상준,김태현 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.8
Modern aircraft are under a severe operating environment, in which uncertainties in mass, stiffness, and aerodynamic characteristics could play an important role in determining the safety of an airplane. Recently, several analysis methodologies have been proposed to find a new critical flight condition in the presence of the system uncertainties. In the present paper, a variation is assumed to exist in the aerodynamic characteristics. A robust aeroelastic analysis is established which accounts for aerodynamic variation due to a different level of compressibility and atmospheric density. Mathematically, the variations in Mach number and atmospheric density are treated as aerodynamic uncertainties. A robust flutter stability boundary is obtained by using the mu method. It is found that the worst case flutter speed, dynamic pressure, and atmospheric density results are all more conservative than the nominal flutter results.