• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.178-184
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• 2010

We present linear particle depolarization ratios (LPDRs) retrieved from measurements with an AERONET Sun photometer at the Gwangju Institute of Science and Technology (GIST), Korea ($35.10^{/circ}N$, $126.53^{\circ}E$) between 19 October and 3 November 2009. The Sun photometer data were classified into three categories according to ${\AA}$ngstr$\ddot{o}$ exponent and size distribution: 1) pure Asian dust (19 October 2009), 2) Asian dust mixed with urban pollution observed in the period from 20-26 October 2009, and 3) clean conditions (3 November). We show that the LPDRs can be used to distinguish among Asian dust, mixed aerosol, and non-Asian dust in the atmosphere. The mean LPDR of the pure Asian dust case is 23 %. Mean LPDRs are 13 % for the mixed case. The lowest mean LPDR is 6 % in the clean case. We compare our results to vertically resolved LPDRs (at 532 nm) measured by a Raman LIDAR system at the same site. In most cases, we find good agreement between LPDRs derived with Sun photometer and measured by LIDAR.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2010년도 춘계학술대회 논문집
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• pp.498-499
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• 2010

• 천문학회지
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• 제33권3호
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• pp.165-172
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• 2000

A baffle system for an airglow photometer, which will be on board the Korea Sounding Rocket-III(KSR-III), has been designed to suppress strong solar scattered lights from the atmosphere below the earth limb. Basic principles for designing a baffle system, such as determination of baffle dimensions, arrangement of vanes inside a baffle tube, and coating of surfaces, have been reviewed from the literature. By considering the constraints of the payload size of the KSR-III and the incident angle of solar light scattered from the earth limb, we first determined dimensions of a two-stage baffle tube for the airglow photometer. We then calculated positions and heights of vanes to prohibit diffusely reflected lights inside the baffle tube from entering into the photometer. In order to evaluate performance of the designed baffle system, we have developed a ray tracing program using a Monte Carlo method. The program computed attenuation factors of the baffle system on the order of $10^{-6}$ for angles larger than $10^{\circ}$, which satisfies the requirements of the KSR-III airglow experiment. We have also measured the attenuation factors for an engineering model of the baffle system with a simple collimating beam apparatus, and confirmed the attenuation factors up to about $10^{-4}$. Limitation of the apparatus does not allow to make more accurate measurements of the attenuation factors.

• Safety and Health at Work
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• 제11권1호
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• pp.61-70
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• 2020

Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-Companion^TM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-Companion^TM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-Companion^TM) and the data detected by the flame photometer (R² = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

• 대기
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• 제33권2호
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• pp.197-222
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• 2023

Remote sensing becomes a new and core framework for the atmospheric sciences and closely related areas concerning with the ever-changing global environmental status. However, remote sensing in the Korea Meteorological Society is relatively new, where the first relevant paper is appeared in 1983, as well as is an area with relatively limited number of research groups. Here, we review and summarize some of the key progress in this area within Korea Meteorological Society focusing on the areas of satellite, radar, and ground based remote sensing such as lidar, spectrometer and sun photometer. Overall, the area is shown to have the most significant progress occur along with the acquisition of the key infra structures such as the COMS (Communication, Ocean and Meteorological Satellite) and S-band radar system led by Korea Meteorological Administration in early 2000. After that, the area has quickly developed into a status playing important roles to lead and support the overall activities in the atmospheric measurements. It is expected that the importance and role of the remote sensing will increase in the coming years.

• 대한원격탐사학회지
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• 제36권3호
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• pp.425-439
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• 2020

최근 성능이 크게 개선된 정지궤도 기상위성 Himawari-8, GK2A등이 운용됨에 따라 시공간적으로 보다 고해상도 AOD(Aerosol Optical Depth) 자료의 사용이 가능해졌다. 본 연구에서는 최근 4년간 한반도내 AERONET(Aerosol Robotic Network) 참여 5개 지점(서울대학교, 연세대학교, 한국외국어대학교, 광주과학기술원(GIST), 안면도 기후변화감시센터)의 에어로졸 관측 자료를 이용하여 Himawari-8/AHI(Advanced Himawari Imager) 에어로졸 산출물의 특징과 두 AOD 자료 간에 차이가 발생하는 원인에 대해 분석하였다. 분석결과 위성과 지상관측 AOD는 하늘이 맑을 경우(운량 < 3)에는 지리적 위치에 관계없이 매우 유사하게 나타났다. 하지만 운량이 증가할 경우 위성 관측과 지상관측 AOD의 차이는 지리적 위치에 관계없이 현저하게 증가하였다(편의: 0.05(맑음) → 0.21(전체), 상관계수: 0.74 → 0.64, RMSE: 0.21 → 0.51). 5개 지점 모두에서 운량이 많거나 상대습도가 높을 때 위성이 지상관측에 비해 AOD를 크게 과대 추정하는 것으로 보아 두 AOD 자료 간의 차이는 주로 운량과 상대습도와 관련이 깊은 것으로 판단된다. 하지만 풍속, 가강수량, 구름 하부 높이, 그리고 옹스트롬 지수(Angstrom Exponent)는 두 AOD 자료 간의 차이에 영향을 미치지 않는 것으로 보인다. 본 연구의 결과는 운량이 많을 경우 위성 관측 AOD 자료 사용시 주의가 필요함을 제시한다.

• 대기
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• 제20권4호
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• pp.483-494
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• 2010

The vertical profiles of the extinction coefficient, the backscatter coefficient, and the lidar ratio (i.e., extinction-to-backscattering ratio) for Asian dust and pollution aerosols are determined from Raman (inelastic) and elastic backscatter signals. The values of lidar ratios during two polluted days is found between 52 and 82 sr (July 22, 2009) and 40~60 sr (July 31, 2009) at 52 nm, with relatively low value of particle depolarization ratio (<5%) and high value of sun photometer-derived Angstrom exponent (> 1.2). However, lidar ratios between 25 and 40 sr are found during two Asian dust periods (October 20, 2009 and March 15, 2010), with 10~20% of particle depolarization ratio and the relatively low value of sun photometer-derived Angstrom exponent (< 0.39). The lidar ratio, particle depolarization ratio and color ratio are useful optical parameter to distinguish non-spherical coarse dust and spherical fine pollution aerosols. The comparison of aerosol extinction profiles determined from inelastic-backscatter signals by the Raman method and from elastic-backscatter signals by using the Fernald method with constant value of lidar ratio (50 sr) have shown that reliable aerosol extinction coefficients cannot be determined from elastic-backscatter signals alone, because the lidar ratio varies with aerosol types. A combined Raman and elastic backscatter lidar system can provide reliable information about the aerosol extinction profile and the aerosol lidar ratio.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.152-152
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• 2010

본 연구에서는 인광 효과가 큰 heavy metal 인 이핵 Iridium 착체가 합성된 구조적, 광학적 및 전기적 특성을 배경으로 하였다. 가교제로는 카본 conjugated 된 리간드 bipyridine계 배위자를 사용하여 단핵 및 이핵 Platinum 착물 화합물을 합성 하였다. 합성 되어진 이핵 Platinum 착물 화합물의 화학적 구조를 결정하기 위해 $^1H(^{13}C)$-NMR, UV-vis, Spectro Photometer, MALDI TOF-MS 등을 사용하였으며, 광 물리적, 전기화학적 측정을 Spectrofluoromete, Cyclic Voltammetry를 통해 관찰 하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.404-408
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• 1998

Yellow sand event has been studied using SeaWiFS data in order to examine the aerosol optical characteristics in the Yellow Sea and their influences on the atmospheric correction for the ocean color remote sensing. Two SeaWiFS images of April 18 and April 25, 1998, representing Yellow Sand event and clear-sky case respectively, are selected for emphasizing the impact of high aerosol concentration on the ocean color remote sensing. It was shown that NASA's standard atmospheric correction algorithm treats yellow sand area as either too high radiance or cloud area, in which ocean color information is not generated. SeaWiFS aerosol optical thickness is compared with nearby ground-based sun photometer measurements and also is compared with radiative transfer simulation in conjunction with yellow sand model, examining the performance of NASA's atmospheric correction algorithm in case of the heavy dust event.

• 대한원격탐사학회지
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• 제32권2호
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• pp.97-104
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• 2016

본 연구에서는 일본 오사카에서 AERONET 선포토미터로 관측된 데이터를 분석하여 440, 675, 870, 1020 nm 파장에서의 입자 편광소멸도를 산출하였다. 산출된 결과는 같은 지역에서 측정된 라이다 자료로부터 얻어진 532 nm에서의 입자 편광소멸도와 비교하였다. 두 값은 440 nm를 제외하고는 잘 일치되는 결과를 보였고, 상관계수($R^2$)는 440, 675, 870, 1020 nm에서 각각 0.28, 0.81, 0.88 0.89의 값을 보였다. 가장 높은 상관계수를 보인 1020 nm에서의 입자 편광소멸도를 기준으로 값의 변화에 따른 입자의 혼합정도를 확인하였을 때, 순수 황사의 경우 높은 편광소멸도를 보이고 오염입자가 혼합될수록 값이 낮아짐을 보였다. 이는 단산란 알베도와 입자 크기 분포를 통하여 확인하였다.