• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.800-805
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• 2017

Randomly patterned and wet chemical etching processes were used to treat anti-glare of display cover glasses. The surface and optical properties of grain size and surface morphology controlled by randomly patterned etching and wet chemical solution etching were investigated. The surface morphology and roughness of the etched samples were examined using a spectrophotometer and a portable surface roughness (Ra) measuring instrument, respectively. The gloss caused by reflection from the glass surface was measured at $60^{\circ}$ using a gloss meter. The surface of the sample etched by the doctor-blade process was more uniform than that obtained from a screen pattern etching process at gel state etching process of the first step. The surface roughness obtained from the randomly patterned etching process depended greatly on the mesh size, which in turn affected the grain size and pattern formation. The surface morphology and gloss obtained by the etching process in the second step depended primarily on the mesh size of the gel state etching process of the first step. In our experimental range, the gloss increased on decreasing the grain size at a lower mesh size for the first step process and for longer reaction times for the second step process.

• 대한원격탐사학회지
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• 제36권5_1호
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• pp.785-791
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• 2020

대기효과로 인해 위성에서 측정된 복사휘도는 오차를 가지고 있다. 대기보정은 대기효과를 제거하여 지표반사도를 산출하는 과정이며, 지표반사도는 복사전달모델 기반의 조견표(Look-Up Table; LUT)를 통해 산출된다. 일반적으로 조견표를 사용하는 연구들은 동일한 대기·기하조건으로 채널별 조견표를 구축하고 있다. 하지만, 대기 조건들이 민감하게 반응하는 채널은 모두 다르다. 이에 본 연구에서는 동일한 대기·기하조건으로 KOMPSAT-3/3A의 채널별 조견표를 구축하고, 복사전달모델에서 모의된 대기상단 복사휘도 및 지표반사도를 검증 자료로 활용하여 조견표의 정확도를 확인하였다. 결과적으로, 에어로졸 광학 두께에 민감하게 반응하는 Blue 채널에서 지표반사도의 상대오차가 최대 81.14%으로 나타났고, NIR 채널에서는 최대 42.67%으로 나타났다.

• 분석과학
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• 제25권6호
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• pp.435-440
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• 2012

지표수 중에 과염소산이온을 LC-ESI-MS/MS을 사용하여 분석하였다. 시료는 단지 PTFE 필터를 사용하여 거른 후 LC-ESI-MS/MS 시스템에 직접 주입하여 분석하였다. 이 방법은 3% 이내의 정밀도를 보였고 정량한계는 0.17 ${\mu}g/L$이었다. 시료는 금강물 35 개 유역에서 2, 4, 6월에 각각 시료를 채취하였다. 그 결과 일반 하천수에서는 과염소산이온이 0.23-3.73 ${\mu}g/L$ (평균 0.20 ${\mu}g/L$) 농도범위로 15% 빈도로 검출되었고 공단 근처의 지표수에서는 0.36-25.10 ${\mu}g/L$ (평균 1.69 ${\mu}g/L$)로 36%의 빈도로 검출되었다.

• 분석과학
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• 제25권6호
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• pp.467-475
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• 2012

지표수 중에 GC-MS에 의한 페놀, 다환방향족탄화수소 및 농약류를 포함한 17 개 유해화합물을 동시에 분석하는 방법을 개발하였다. 1.0 L의 물 시료를 분액깔대기 안에 넣고 NaCl로 포화시킨 다음 40mL methylene chloride로 추출하였다. 이 방법은 1.0-10 ng/L 범위의 정량한계를 보였고 22% 이내의 정밀도를 보였다. 확립한 방법을 사용하여 35 지역의 금강 물 70 개 시료를 분석한 결과 유해화합물이 1.1-26,604 ng/L의 농도범위로 검출되었으며 측정값은 외국에서 확립한 준거치를 초과하는 값은 없었다. 이 측정방법은 지표수에서 유해화합물에 대한 국가모니터링사업에 사용할 때 효율적인 것으로 판단된다.

• 한국토양비료학회지
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• 제49권1호
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• pp.81-86
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• 2016

Heavy metal pollution in agricultural fields at the abandoned metal mines has been serious problems in Korea. In order to manage heavy metal pollution in surface water and soil, numerous remediation strategies have been established. Therefore, main purpose of this research was to examine feasibility of ecological toxicity assessment for establishing management strategy in heavy metal polluted agricultural fields. Heavy metal concentration in surface water and soil was monitored along with ecotoxicity experiment with Daphnia magna and Eisenia fetida. Result showed that high toxicity was observed in heavily polluted agricultural field with heavy metals. In case of mortality of Daphnia magna (85%) and Eisenia fetida (6.7%), the highest ratio was observed when heavy metal concentration in surface and soil was high. Calculated ecotoxicity index (EI) ranged 0.06-0.30 and the highest EI was observed in heavily polluted sites among 5 abandoned metal mines. Overall, ecological toxicity assessment is necessary to evaluate heavy metal pollution in agricultural fields near at the abandoned metal mines along with chemical concentration analysis.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.352-364
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• 2017

A novel 3D mathematical model for water film runback and icing on a rotating surface is established in this work, where both inertial forces caused by the rotation and shear forces due to the air flow are taken into account. The mathematical model of the water film runback and energy conservation of phase transition process is established, with a cyclical average method applied to simulate the unsteady parameters variation at angles of attack. Ice accretion on a conical spinner surface is simulated and the results are compared with the experimental data to validate the presented model. Then Ice accretion on a cowling surface is numerically investigated. Results show that a higher temperature would correspond to a larger runback ice area and thinner ice layer for glaze ice. Rotation would enhance the icing process, while it would not significantly affect the droplet collection efficiency for an axi-symmetric surface. In the case at angle of attack, the effect of rotation on ice shape is appreciable, ice would present a symmetric shape, while in a stationary case the shape is asymmetric.

• Journal of Periodontal and Implant Science
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• 제53권4호
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• pp.295-305
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• 2023

Purpose: Various methods have been proposed to achieve the nearly complete decontamination of the surface of implants affected by peri-implantitis. We investigated the in vitro debridement efficiency of multiple decontamination methods (Gracey curettes [GC], glycine air-polishing [G-Air], erythritol air-polishing [E-Air] and titanium brushes [TiB]) using a novel spectrophotometric ink-model in 3 different bone defect settings (30°, 60°, and 90°). Methods: Forty-five dental implants were stained with indelible ink and mounted in resin models, which simulated standardised peri-implantitis defects with different bone defect angulations (30°, 60°, and 90°). After each run of instrumentation, the implants were removed from the resin model, and the ink was dissolved in ethanol (97%). A spectrophotometric analysis was performed to detect colour remnants in order to measure the cumulative uncleaned surface area of the implants. Scanning electron microscopy images were taken to assess micromorphological surface changes. Results: Generally, the 60° bone defects were the easiest to debride, and the 30° defects were the most difficult (ink absorption peak: 0.26±0.04 for 60° defects; 0.32±0.06 for 30° defects; 0.27±0.04 for 90° defects). The most effective debridement method was TiB, independently of the bone defect type (TiB vs. GC: P<0.0001; TiB vs. G-Air: P=0.0017; TiB vs. GE-Air: P=0.0007). GE-Air appeared to be the least efficient method for biofilm debridement. Conclusions: T-brushes seem to be a promising decontamination method compared to the other techniques, whereas G-Air was less aggressive on the implant surface. The use of a spectrophotometric model was shown to be a novel but promising assessment method for in vitro ink studies.

• 한국지구과학회지
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• 제43권6호
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• pp.712-736
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• 2022

To understand the characteristics of low-level clouds (CLs), environmental variables are composited on each CL using individual surface observations and six-hourly upper-air meteorologies around the globe. Individual CLs has its own distinct environmental conditions. Over the eastern subtropical and western North Pacific Ocean in JJA, stratocumulus (CL5) has a colder sea surface temperature (SST), stronger and lower inversion, and more low-level cloud amount (LCA) than the climatology whereas cumulus (CL12) has the opposite characteristics. Over the eastern subtropical Pacific, CL5 and CL12 are influenced by cold and warm advection within the PBL, respectively but have similar cold advection over the western North Pacific. This indicates that the fundamental physical process distinguishing CL5 and CL12 is not the horizontal temperature advection but the interaction with the underlying sea surface, i.e., the deepening-decoupling of PBL and the positive feedback between shortwave radiation and SST. Over the western North Pacific during JJA, sky-obscuring fog (CL11), no low-level cloud (CL0), and fair weather stratus (CL6) are associated with anomalous warm advection, surface-based inversion, mean upward flow, and moist mid-troposphere with the strongest anomalies for CL11 followed by CL0. Over the western North Pacific during DJF, bad weather stratus (CL7) occurs in the warm front of the extratropical cyclone with anomalous upward flow while cumulonimbus (CL39) occurs on the rear side of the cold front with anomalous downward flow. Over the tropical oceans, CL7 has strong positive (negative) anomalies of temperature in the upper troposphere (PBL), relative humidity, and surface wind speed in association with the mesoscale convective system while CL12 has the opposite anomalies and CL39 is in between.

• 대한원격탐사학회지
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• 제39권6_1호
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• pp.1497-1503
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• 2023

본 연구는 Near-UltraViolet (UV) 파장에서의 지표면 반사도 산출 시 발생하는 구름과 적설의 분류 한계를 극복하기 위해 Geostationary Environmental Monitoring Spectrometer (GEMS)와 Advanced Meteorological Imager (AMI) 위성의 구름 자료를 융합하여 적설역에서의 지표면 반사도 품질을 향상시키는 방법을 제안한다. GEMS 구름 산출물과 AMI 구름탐지 자료를 기반으로 융합 구름자료를 생산하였으며, 이를 GEMS 지표면 반사도 산출에 적용하였다. 그 결과 적설역에서 GEMS 구름 산출물만 사용한 경우에 비해 미산출이 개선되었으며 이는 전체 관측 영역에서 약 17%의 개선 효과를 확인하였다. 본 연구 결과는 융합 구름자료를 활용하여 적설역에서 지속적으로 발생했던 지표면 반사도 미산출 문제를 개선할 수 있음을 입증하며, 이를 통해 산출된 고품질의 지표면 반사도를 기반으로 타 Level-2 산출물의 품질향상을 기대할 수 있다.

• 대한환경공학회지
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• 제29권9호
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• pp.1020-1026
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• 2007

전 세계적으로 병원성 미생물에 의한 오염과 감염 및 발병의 사례가 급증함에 따라 병원성 미생물을 효율적으로 제어하는 기술에 대한 관심이 매우 증가하고 있다. 병원성 미생물을 환경에서 제어하는 연구는 대다수 수처리 공정과 같이 물에서 이루어지는 소독과 관련되어 진행되어 왔고, 표면에서의 소독에 관련된 연구는 매우 부족하였다. 본 연구는 UV 소독 방법을 표면에 분포된 미생물의 불활성화에 대해서 적용하여 살펴보았고, 소독 모델을 통해서 정량화하였다. 특히, 생물테러용 무기로 잘알려진 탄저균(Bacillus anthracis)의 지표 미생물인 바실러스 포자(Bacillus subtilis spore)에 대해서 UV를 이용한 표면 소독시 매우 빠른 불활성화를 볼 수 있었으며, 2 log(99%) 불활성화를 위한 IT 값은 14.5 $mJ/cm^2$으로 나타났다. UV에 의한 미생물 불활성화는 화학적 소독제의 경우와 달리 온도에 의한 영향은 나타나지 않았으나, 표면 거칠기(surface roughness)에 의한 뚜렷한 tailing off 현상이 나타났다.