• Journal of Photoscience
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• 제9권2호
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• pp.457-459
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• 2002

Sunlight causes various types of adverse skin changes on the sun-exposed areas of the skin, in which the most hazardous one is the induction of malignant skin tumours. FT -IR spectra were obtained from specimens excised from normal skin, BCCs, SCCs, MMs, nevi, lesions of solar keratosis and Bowen's disease. Tissue samples from freshly frozen specimens were cut into 2 sections in strictly sequential order to be stained with H & E for histopathological analysis, and then to be air-dried on CaF$_2$ slide glasses for further spectral data acquisition from defined area of interest. Intra- and inter-sample variations were estimated within grouped lesion categories according to each skin component. Mean spectra for each type of tissue pathology in the 800-1800 $cm^{-1}$ / region was interpreted using the classical group frequency approach that showed the most visible differences in spectra of benign, premalignant and malignant changes directly related to protein conformation and nucleic acid bases. The relative intensity of the nucleic acid peak was increased with progression to malignancy. In addition, PCA was able to evaluate and maximise the differences in the spectra by reducing the number of variables characterizing each patient and pathology category. This type of approach to non-destructively estimate the complexity of IR-spectra of inhomogeneous samples such as skin demonstrates the advantage of FT -IR microspectroscopy to be able to observe diseased states (benign, premalignant, malignant) and distinguish them from normal against a huge background of inter- and intra-subject variability.

• 분석과학
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• 제18권5호
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• pp.403-409
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• 2005

최근 내분비계장애물질로 알려진 PAHs 화합물 중 하나인 벤조피렌은 대표적인 PAHs 화합물로 음식을 조리, 가공할 때 식품의 주성분인 탄수화물, 단백질, 지방 등이 분해되어 생성되는 열분해 산물이며 토양, 공기, 물, 식품 등 전 환경매체에서 검출되고 있다. 본 연구에서는 PAHs[benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, indeno(1,2,3-c,d)pyrene]에 대하여 어류 중 지방의 알칼리 분해시간에 따른 분해효율, 추출 용매에 따른 추출효율, 정제컬럼의 용출량에 따른 정제효율 등을 비교 실험하여 알칼리분해를 이용한 어류 중 PAHs의 전처리방법을 확립하고자 하였다. 균질화된 시료를 알칼리 분해하여 n-hexane으로 추출하고 증류수로 세척한 후 Sep-Pak florisil cartridge로 정제하여 HPLC/FLD(고속액체크로마토그래피/형광검출기) 로 동시 정량 분석하였으며 각각의 PAHs에 대한 회수율은 약 90~106% 수준이었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.141-141
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• 2012

The electronic and optical properties of Indium Zinc Tin Oxide (IZTO) thin films using gas environment were investigated by X-ray photoelectron spectroscopy (XPS) and reflection electron energy loss spectroscopy (REELS). REELS spectra revealed that the band gaps of IZTO thin films are 3.26, 3.07, and 3.46 eV for water mixed with oxygen, argon mixed with oxygen, and air environments, respectively. The measured band gaps by REELS are consistent with the optical band gaps obtained by UV-Spectrometer. The optical properties represented by the dielectric function $\mathfrak{m}$, the refractive index n, the extinction coefficient k, and the transmission coefficient T of the IZTO thin films with different gas environments were determined from a quantitative analysis of REELS spectra. The calculated transmission from quantitative analysis of REELS spectra shows good agreement with transmission measured by UV-spectrometer. The transmission values of 89% and low electrical resistivity of $3.55{\times}10^{-3}{\Omega}{\cdot}cm$ have been achieved for argon mixed with oxygen which indicates that the gas enviroment plays an important role in improving the electronic and optical properties of films.

• 한국전기전자재료학회논문지
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• 제31권5호
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• pp.345-350
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• 2018

Nanomaterials have considerable potential to solve several key challenges in various electrochemical devices, such as fuel cells. However, the use of nanoparticles in high-temperature devices like solid-oxide fuel cells (SOFCs) is considered problematic because the nanostructured surface typically prepared by deposition techniques may easily coarsen and thus deactivate, especially when used in high-temperature redox conditions. Herein we report the synthesis of a self-regenerated Pd metal nanoparticle on the perovskite oxide anode surface for SOFCs that exhibit self-recovery from their degradation in redox cycle and $CH_4$ fuel running. Using Pd-doped perovskite, $La(Sr)Fe(Mn,Pd)O_3$, as an anode, fairly high maximum power densities of 0.5 and $0.2cm^{-2}$ were achieved at 1,073 K in $H_2$ and $CH_4$ respectively, despite using thick electrolyte support-type cell. Long-term stability was also examined in $CH_4$ and the redox cycle, when the anode is exposed to air. The cell with Pd-doped perovskite anode had high tolerance against re-oxidation and recovered the behavior of anodic performance from catalytic degradation. This recovery of power density can be explained by the surface segregation of Pd nanoparticles, which are self-recovered via re-oxidation and reduction. In addition, self-recovery of the anode by oxidation treatment was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

• 분석과학
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• 제14권2호
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• pp.167-172
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• 2001

계면활성제를 이용하여 한지 섬유질 슬러지를 폐수시료로부터 효율적으로 제거하는 방법에 대해 연구하였다. 섬유질 슬러지의 농도가 약 80mg/L 인 실험 시료를 음이온 계면활성제인 sodium oleate를 이용하여 부상시켜 제거하려고 할 때 농도는 10mg/L, 유리필터 구멍크기는 $5-10{\mu}m$, 공기 유속은 200 mL/min이 적당하였다. Sodium oleate는 $Ca^{2+}$ 이온과 같은 다가 양이온에 의해 방해를 받을 수 있는데 $Ca^{2+}$ 이온의 농도가 100mg/L 이하일 경우에는 영향이 없었다. 양이온 계면활성제인 cetyltrimethylammonium bromide(CTAB)를 이용하였을 때는 sodium oleate보다 제거율이 좋지 않았으며, 거품도 비교적 많이 생겼다. 전통한지 제조과정에서 분산제로 사용되는 $PAMID^{(R)}$를 실험 재료에 1mg/L 가한 후 CTAB를 1mg/L 가하더라도 섬유질 슬러지들이 매우 잘 엉겼으며 부상시켰을 때 30초 이내에 95% 이상 제거되었으나 sodium oleate는 효과적이지 못하였다.

• 한국의류산업학회지
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• 제20권5호
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• pp.592-599
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• 2018

The purpose of this study is to investigate consumer needs, image sensibility and preference of bedding fabric according to size and spacing of dot pattern. 18 kinds of dot pattern fabrics were designed with different diameters(6, 8, 10cm) and distances(4, 7, 10cm) in regular arrangement of diamond figure. The subjects were 162 male and female university students. The data were analyzed by SPSS 24.0. Fabrics were assessed subjectively using a 5-point scale 17 consumer needs and 33 sensory descriptors. The most consumer's needs for bedding fabric was shown to be functionality of bedding including hygiene, touch, warmth, ease of washing and management, air permeability, and hygroscopicity. The other parameters of consumer's needs were shown to be physical property and design parameter. The results of analysis of the dimension of image sensibility for fabrics with different size and spacing of dots are derived from six factors including joyfulness, coziness, uniqueness, charm, femininity, and complexity. As a result of analysis of preference with fabric kinds, there was a significant difference in preference with fabrics. The preferred fabrics were characterized by the pattern and the base fabric being striking three-dimensionally with 1/3 twill and 3/1 twill fabric. Sensory descriptors related to joyful image and unique image were analyzed as evaluation terms that can distinguish the preferences of fabrics. Correlation analysis showed the fabrics are preferred as the difference in luminance and reflectance between the base and pattern of the fabric become larger and the spacing of patterns become closer.

• 센서학회지
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• 제3권2호
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• pp.3-10
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• 1994

LB막의 안정성을 향상시키기 위하여 고분자 LB막의 가교화를 시도하였다. AT-cut 수정진동자를 이용하여 LB누적막의 특성을 분석하여 보았다. 합성한 전개 고분자의 폴리 에테르기가 공기/물 계면에 누워 있는 상태로 존재하지만, 표면압을 가하면 하층액에 수화되어 잠기게 된다. 이와 같은 메카니즘은 하층액에 폴리 알릴 아민과 NaCl, $CaCl_{2}$ 등의 염을 녹여서 실험하여, 더욱 명확히 확인할 수 있었다. 그리고 LB막의 특성을 AT-cut 수정진동자를 이용하여 온라인으로 분석할 수 있었다.

• 대한기계학회논문집B
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• 제29권9호
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• pp.988-996
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• 2005

Flame structure and extinction mechanism of counterflow methane/air non-premixed flame diluted with nitrogen are studied by NASA 2.2 s drop tower experiments and two-dimensional numerical simulations with finite rate chemistry and transport properties. Extinction mechanism at low strain rate is examined through the comparison among results of microgravity experiment, 1D and 2D simulations with a finite burner diameter. A two-dimensional simulation in counterflow flame especially with a finite burner diameter is shown to be very important in explaining the importance of multidimensional effects and lateral heat loss in flame extinction, effects that cannot be understood using a one-dimensional flamelet model. Extinction mechanism at low strain rate is quite different from that at high strain rate. Low strain rate flame is extinguished initially at the outer flame edge, the flame shrinks inward, and finally is extinguished at the center. It is clarified from the overall fractional contribution by each term in energy equation to heat release rate that the contribution of radiation fraction with 1D and 2D simulations does not change so much and the overall fractional contribution is decisively attributed to radial conduction ('lateral heat loss'). The experiments by Maruta et at. can be only completely understood if multi-dimensional heat loss effects are considered. It is, as a result, verified that the turning point, which is caused only by pure radiation heat loss, has to be shifted towards much lower global strain rate in microgravity flame.

• 분석과학
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• 제24권6호
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• pp.429-434
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• 2011

본 연구에서는 마이크로 크기의 입자(안료, 대기입자, 등)를 수집과 동시에 물에 분산된 상태로 분획가능한 장치를 개발하였다. 이 장치에서는 물을 넣은 입자수집용 실린더 세 개를 직렬로 연결하여 공기를 통과하게 하였다. 그럼으로써 크기가 다른 입자들이 다른 실린더에 모아지도록 하였고, 수집과 동시에 분획이 가능하도록 하였다. 이 장치의 중요한 특징은 막필터(membrane filter)를 사용하지 않는다는 점이다. 즉, 필터를 사용하지 않고 마이크로 크기의 입자를 직접 시료 수집용 실린더에 수집되도록 하였다. 또한 수집된 시료는 수집되는 동안 물에 분산된 상태로 장치 내에서 동시분획이 가능하다. 이 장치를 에어본 입자의 수집에 응용하였다. 수집된 에어본 입자는 침강 장-흐름 분획법(sedimentation field-flow fractionation, SdFFF)을 이용하여 입자 크기별로 분획하였고, 광학현미경(optical microscopy, OM)을 이용하여 입자 크기와 모양을 관찰하였다. 또한 AAS와 ICP-AES를 이용하여 에어본 입자들의 조성을 분석하였다. 본 연구를 통하여 개발한 입자 수집 및 분획장치는 다양한 종류의 입자의 수집 및 크기분포 분석에 활용이 가능할 것으로 기대한다.

• 한국대기환경학회지
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• 제30권6호
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• pp.531-537
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• 2014

Terrestrial vegetation has been known as a main source of biogenic volatile organic compounds (BVOCs). Isoprene and monoterpene among the BVOCs are most abundant species emitted by forests, and have a significant impact on atmospheric chemistry. Abundancy of these species could lead to an increase or decrease in the production of natural tropospheric ozone in forests, depending on the nitric oxide (NO) concentration. Soil is the most significant source of natural NO. Understanding of NO emission from forest soil could be critical in evaluation of air quality in the forest area. Flux-gradient similarity theory (FGST) was applied for practical use to estimate forest soil NO emission at Mt. Taewha where is available micro-meteorological data near surface monitoring from flux tower. NO fluxes calculated by FGST were compared to flux results by flow-through dynamic chamber (FDC) measurement. Surface NO emission trends were shown between two different techniques, however their magnitudes were found to be different. NO emissions measured from FDC technique were relatively higher than those from theoretical results. Daily mean NO emissions resulted from FGST during Aug. 13, 14 and 15 were $0.28{\pm}8.45$, $2.17{\pm}15.55$, and $-3.18{\pm}13.65{\mu}gm^{-2}hr^{-1}$, respectively, while results from FDC were $2.26{\pm}1.44$, $5.11{\pm}3.85$, and $2.23{\pm}6.45{\mu}gm^{-2}hr^{-1}$. Trends of daily means were shown in similar pattern, which NO emissions were increasing during late afternoon ($r^2$=0.04). These emission trends could be because soil temperature and moisture influence importantly soil microbiology.