• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1719-1723
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• 2002

1,5-diphenylcarbazone was immobilized on sodium dodecyl sulfate coated alumina. The alumina particle was effectively used for collection of mercury(II) and methylmercury cations at sub-ppb level. The adsorbed mercury was eluted with l mol $L^{-1}$ of hydrobromic acid solution. The mercury(II) was then directly measured by cold vapor atomic absorption spectrometry utilizing tin (II) chloride where as the total mercury was determined after the oxidation of methylmercury into the inorganic mercury. The methylmercury concentration was calculated by the difference between the value of total mercury and mercury (II). Mercury (II) and methylmercury cations were completely recovered from water with a preconcentration factor of 100 (for 1 L solution.) Relative standard deviation at Hg L ${\mu}gL^{-1}$ level 1.7%(n=8) and the limit of detection was 0.11 ${\mu}gL^{-1}$. The procedure was applied to spring water, well water and seawater and accuracy was assessed through recovery experiments.

• 분석과학
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• 제12권4호
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• pp.273-278
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• 1999

수은과 비소를 동일한 반응조건으로 환원 증기 발생법-유도결합 플라즈마 원자방출 분광계로 동시에 분석할 수 있는 방법을 연구하였다. 수은과 비소는 휘발성이 강하므로 시료를 마이크로파 용해 장치와 산을 이용한 추출법으로 전처리를 실시하였다. 환원 증기 발생법 반응조건은 6N HCl과 2% $NaBH_4$로 비교적 농도를 진하게 사용하였으며, 이 조건에서 검출한계는 수은과 비소가 각각 0.06 ppb, 0.08 ppb를 얻었다. 수은은 모두 표준시료의 검증값에 일치하였으며 비소도 무기물 시료에서는 검증값에 일치하였으나 유기물 시료에서는 약 80%의 회수율을 얻었다.

• Journal of Radiation Protection and Research
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• 제30권1호
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• pp.27-30
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• 2005

New possibilities are discussed for cholesteric liquid crystals (CLC) as sensor materials for detection of ionizing radiation, biologically active UV radiation, and the presence of hazardous vapors in atmosphere. A distinguishing property of CLC-based detectors is their 'bioequivalence', i.e., mechanisms of their response to external factors essentially imitate the corresponding mechanisms of biological tissues. Such detectors can ensure sufficiently high sensitivity to make feasible their use as alarm indicators or in biophysical studies. Specific examples ate given of sensor compositions and their response characteristics.

• 통합자연과학논문집
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• 제3권4호
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• pp.202-205
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• 2010

Nanocrystalline porous silicon surfaces have been used to detect nitroaromatic compounds in vapor phase. The mode of photoluminescence is emphasized as a sensing attitude or detection technique. Quenching of photoluminescence from nanocrystalline porous surfaces as a transduction mode is measured upon the exposure of nitroaromatic compounds. Reversible detection mode for nitroaromatics is, too, observed. To verify the detection afore-mentioned, photoluminescent freshly prepared porous silicons are functionalized with different groups. The mechanism of quenching of photoluminescence is attributed to the electron transfer behaviors of quantum-sized nano-crystallites in the porous silicon matrix to the analytes(nitroaromatics). An attempt has been done to prove that the surface-derivatized photoluminescent porous silicone surfaces can act as versatile substrates for sensing behaviors due to having a large surface area and highly sensitive transduction mode.

• 한국광학회지
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• 제22권6호
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• pp.283-290
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• 2011

수증기의 혼합비를 측정하기 위하여 라만 라이다 시스템을 설계 제작하였다. 시스템을 검증하기 위하여 가강수량과 분포에 대하여 상용 마이크로파 라이오메터(MWR)와 GPS 신호를 이용하는 방법과 비교 연구를 수행하였다. GNSS 방법으로 측정한 총가강수량과 본 라이다 방법에서는 작은 차이를 보였는데, 이는 라이다 방법으로 얻을 수 있는 수증기의 측정고도가 제한적이기 때문이다. 반면에 MWR 방법과 라이다 방법으로 얻은 고도에 따른 수증기량은 수증기량이 급격하게 변하는 구름 경계나 경계고도 근처에서 심한 차이를 보이고 있었다. MWR은 그 밀도가 급격하게 변하는 곳에서 취약한 점을 보였으나 개발된 라만 라이다의 경우는 그 밀도가 급격히 변하는 곳에서도 측정이 원활하게 이루어지고 있음을 알 수 있었다.

• 품질경영학회지
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• 제38권3호
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• pp.354-362
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• 2010

This paper presents a non-linear control chart based on support vector machine regression (SVM-R) to improve the accuracy of fault detection of cyclic signals. The proposed algorithm consists of the following two steps. First, the center line of the control chart is constructed by using SVM-R. Second, we calculate control limits by variances that are estimated by perpendicular and normal line of the center line. For performance evaluation, we apply proposed algorithm to the industrial data of the chemical vapor deposition process which is one of the semiconductor processes. The proposed method has better fault detection performance than other existing method

• 통합자연과학논문집
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• 제2권3호
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• pp.211-214
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• 2009

A new porous silicon (PSi) microcavity sensor for the detection of volatile organic compounds (VOCs) was developed. PSi microcavity sensor exhibiting unique reflectivity was successfully obtained by an electrochemical etching of silicon wafer. When PSi was fabricated into a structure consisting of two high reflectivity muktilayer mirrors separated by an active layer, a microcavity was formed. This PSi microcavity is very sensitive structures. Reflection spectrum of PSi microcavity indicated that the full-width at half-maximum (FWHM) was of 10 nm and much narrower than that of fluorescent organic molecules or quantum dot. The detection of volatile organic compounds (VOCs) using PSi microcavity was achieved. When the vapor of VOCs condensed in the nanopores, the refractive indices of entire particle increased. When PSi microcavity was exposed to acetone, ether, and toluene, PSi microcavity in reflectivity was red shifted by 28 nm, 33 nm, and 20 nm for 2 sec, respectively.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2070-2075
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• 2008

Identification of steady-state is the first step in developing a fault detection and diagnosis (FDD) system. In a complete FDD system, the steady-state detector will be included as a module in a self-learning algorithm which enables the working system's reference model to "tune" itself to its particular installation. In this study, a steady-state detector of a residential air conditioner based on moving windows was designed. Seven representing measurements were selected as key features for steady-state detection. The optimized moving window size and the feature thresholds was suggested through startup transient test and no-fault steady-state test. Performance of the steady-state detector was verified during indoor load change test. From the research, the general methodology to design a moving window steady-state detector was provided for vapor compression applications.

• 한국환경농학회지
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• 제26권3호
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• pp.254-258
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• 2007

국내에서 합성, 개발된 유기인계 살충제인 bistrifluron의 물리화학적 특성으로 수용성, 가수분해, 증기압을 미국 EPA와 OECD 방법에 준하여 측정하였다. 수용성은 $25^{\circ}C$에서 30 ppb로 낮았고 가수분해 반감기는 $20^{\circ}C$에서 10.9일(pH 9.0) 이었고 pH 7.0 조건에서는 전혀 분해가 안되었으며, $40^{\circ}C$에서는 20.6일(pH 7.0), 1.5일(pH 9.0) 이었다. 상온$(25^{\circ}C)$에서의 증기압 측정은 시험기간 중 bistrifluron이 검출되지 않아 bistrifluron의 검출한계(50 ng)를 적용하여 계산한 ${\leq}2.05{\times}10^{-8}$ torr를 bistrifluron의 증기압으로 결정하였다. 이 수치를 보면 bistrifluron은 휘발에 의하여 환경에 영향을 미칠 가능성이 낮을 것으로 판단된다.

• 대한원격탐사학회지
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• 제32권4호
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• pp.339-351
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• 2016

For the safety of sea, it is important to monitor sea fog, one of the dangerous meteorological phenomena which cause marine accidents. To detect and monitor sea fog, Moderate Resolution Imaging Spectroradiometer (MODIS) data which is capable to provide spatial distribution of sea fog has been used. The previous automatic sea fog detection algorithms were focused on detecting sea fog using Terra/MODIS only. The improved algorithm is based on the sea fog detection algorithm by Wu and Li (2014) and it is applicable to both Terra and Aqua MODIS data. We have focused on detecting spring season sea fog events in the Yellow Sea. The algorithm includes application of cloud mask product, the Normalized Difference Snow Index (NDSI), the STandard Deviation test using infrared channel ($STD_{IR}$) with various window size, Temperature Difference Index(TDI) in the algorithm (BTCT - SST) and Normalized Water Vapor Index (NWVI). Through the calculation of the Hanssen-Kuiper Skill Score (KSS) using sea fog manual detection result, we derived more suitable threshold for each index. The adjusted threshold is expected to bring higher accuracy of sea fog detection for spring season daytime sea fog detection using MODIS in the Yellow Sea.