• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.218.3-218.3
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• 2003

In this study, a FT-NIR spectroscopy was used to determine skin moisture. NIR diffuse reflectance spectra were collected from separated dorsal and abdominal hairless mouse skin. Partial least squares regression (PLSR) was applied to develop calibration models that determine the water content. The seven spectra regions, such as 833-2500, 1100-2250, 1100-1750, 1750-2250, 1200-1600, 1800-2200, and 1200-2200 except 1600-1800 nm, were investigated for the best model by PLSR. The developed model predicted skin moisture for validation set with a standard errors of prediction (SEP) of 4.43%, when used 833-2500 nm. (omitted)

• 자원리싸이클링
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• 제18권4호
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• pp.24-30
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• 2009

희토류 원소를 기반으로한 알루미늄산 형광체에 담지된 산화티탄은 졸겔방법 으로 제조되었다. 이렇게 제조된 산화티탄 나노입자의 재료물성을 분석하기 위해 XRD, FT-IR, DRS UV-Vis, TEM 측정을 실시하였다. 형광체에 담지된 산화티탄 입자의 소결 전후의 XRD분석결과는 600도 이상의 온도에서 아나타제에서 루틸로 상변화가 일어나지 않았다. 600도 이상의 온도에서 지속적인(장시간) 열처리 후에도 형광체에 담지된 산화티탄이 결정화도가 높은 아나타제로 존재 하는 것은 형광체 지지체와 담지된 산화티탄의 서로 다른 결정입계에 의하여 결정성장과 상변화에 필요한 치밀화가 억제되기 때문으로 판단된다. DRS측정결과 형광체에 담지된 산화티탄은 산화티탄이 없는 형광체에 비하여 보다 긴 장파로 쉬프트한 것은 밴드갭 에너지의 환원을 나타낸다. 이러한 형광체에 담지된 산화티탄의 FT-IR 스펙트럼은 피크의 위치가 더 높은 파수로 이동하였다. 이것은 산화티탄 입자와 지지체 사이의 공유결합이 관계하기 때문 이라 판단된다. TEM 이미지는 형광체 지지체에 다른 입자 크기로 담지되어 있는 산화티탄의 분산, 결정화 및 입자 형상을 나타낸다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.280-284
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• 2004

Multicrystalline silicon wafers were textured in an alkaline bath, basically using sodium hydroxide and in acidic bath, using mainly hydrofluoric acid (HF), nitric acid $(HNO_3)$ and de-ionized water (DIW). Some wafers were also acid polished for the comparative study. Comparison of average reflectance of the samples treated with the new recipe of acidic solution showed average diffuse reflectance less than even 5 percent in the optimized condition. Solar cells were thus fabricated with the samples following the main steps such as phosphorus doping for emitter layer formation, silicon nitride deposition for anti-reflection coating by plasma enhanced chemical vapor deposition (PECVD) and front surface passivation, screen printing metallization, co-firing in rapid thermal processing (RTP) Furnace and laser edge isolation and confirmed >14 % conversion efficiency from the best textured samples. This isotropic texturing approach can be instrumental to achieve high efficiency in mass production using relatively low cost silicon wafers as starting material.

• 한국재료학회지
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• 제23권2호
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• pp.116-122
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• 2013

For fabricating silicon solar cells with high conversion efficiency, texturing is one of the most effective techniques to increase short circuit current by enhancing light trapping. In this study, four different types of textures, large V-groove, large U-groove, small V-groove, and small U-groove, were prepared by a wet etching process. Silicon substrates with V-grooves were fabricated by an anisotropic etching process using a KOH solution mixed with isopropyl alcohol (IPA), and the size of the V-grooves was controlled by varying the concentration of IPA. The isotropic etching process following anisotropic etching resulted in U-grooves and the isotropic etching time was determined to obtain U-grooves with an opening angle of approximately $60^{\circ}$. The results indicated that U-grooves had a larger diffuse reflectance than V-grooves and the reflectances of small grooves was slightly higher than those of large grooves depending on the size of the grooves. Then amorphous Si:H thin film solar cells were fabricated on textured substrates to investigate the light trapping effect of textures with different shapes and sizes. Among the textures fabricated in this work, the solar cells on the substrate with small U-grooves had the largest short circuit current, 19.20 mA/$cm^2$. External quantum efficiency data also demonstrated that the small, U-shape textures are more effective for light trapping than large, V-shape textures.

• 한국세라믹학회지
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• 제38권12호
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• pp.1137-1143
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• 2001

본 연구에서는 적외선 반사체 제조를 위하여 MAS(MgO-Al$_2$O$_3$-SiO$_2$)계 유리로부터 핵행성 및 결정성장의 2단계 열처리에 의해 cordierite(2MgO.2Al$_2$O$_3$5SiO$_2$)와 rutile(TiO$_2$)을 주결정상으로 하는 결정화유리를 제조하였다. MgO-Al$_2$O$_3$-SiO$_2$3성분계 조성에 조핵제로 TiO$_2$를 첨가하여 용융법으로 유리를 제조한 후 결정화 열처리를 하여 핵생성 및 결정화 거동과 결정화유리의 결정상, 입자 크기와 확산 반사율과의 관계를 관찰하였다. 그 결과 75$0^{\circ}C$에서 3시간동안 핵생성 시킨 후 110$0^{\circ}C$/5hr 이상의 열처리 조건에서 cordierite와 rutile이 주결정상으로 석출되었으며 570~2500nm 범위에서 90% 이상의 반사율을 갖는 결정화유리를 제조하였다.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.375-382
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• 2010

A layered perovskite photocatalysts, $SrBi_2Nb_2O_9$ (SBN), was synthesized by the conventional solid-state reaction method and characterized by X-ray diffraction (XRD) and UV-visble spectrophotometry. The results showed that the structure of $SrBi_2Nb_2O_9$ is orthorhombic. Diffuse reflectance spectra for calcined and attrition-milled SBN showed the main absorption edges were less 400 nm, that is ultraviolet region. SBN under micron-sized powder was deposited on the $Al_2O_3$ by room temperature powder spray in vacuum process, so called aerosol deposition (AD), and nano-grained $SrBi_2Nb_2O_9$ photocatalytic thick film was fabricated. AD-deposited SBN thick films were characterized by XRD, scanning electron microscopy (SEM) and UV-visable spectrophotometry, Moreover, it was found that several nano-sized SBN film by AD process can improve the photocatalytic activity under visable reflectance.

• 한국토양비료학회지
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• 제34권4호
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• pp.273-277
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• 2001

실험실에서의 기존의 토양분석방법은 많은 시약을 사용하고 분석시간이 많이 걸린다. 본 연구는 근적외 분광분석기를 이용하여 토양의 여러 가지 이화학성분에 대한 측정결과를 검토하였다. 토양시료를 몰탈로 갈아서 토양입자를 0.2mm의 체를 통과시킨 140점의 토양시료를 85점은 근적외 분광분석기(InfraAlyzer 500, Bran & Luebbe Co.)로 표준곡선을 작성하고 나머지 55점의 토양시료는 표준곡선을 이용하여 토양의 이화학성중에서 토양 pH, CEC, 치환성 Ca, Mg, K 및 유효규산, 휴믹산 및 전기전도도(EC)를 추정하였다. 표준곡선은 부분최소자승법을 이용하여 작성하였다. 토양시료를 곱게 분쇄하면 근적외선의 고른 확산반사를 얻을 수 있어서, 근적외 분광분석기를 이용하여 여러 기지 토양의 화학성을 수초내에 추정할 수 있어 토양검정에 이용할 수 있을 것으로 생각된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.344-347
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• 2008

Ocean surface waves may be modified by ocean current and their observation may be severely distorted if the observer is on a moving platform with changing speed. Tidal current near a sill varies inversely with the water depth, and results spatially inhomogeneous modulation on the surface waves near the sill. For waves propagating upstream, they will encounter stronger current before reaching the sill, and therefore, they will shorten their wavelength with frequency unchanged, increase its amplitude, and it may break if the wave height is larger than 1/7 of the wavelength. These small scale (${\sim}$ 1 km changes is not suitable for satellite radar observation. Spatial distribution of wave-height spectra S(x, y) can not be acquired from wave gauges that are designed for collecting 2-D wave spectra at fixed locations, nor from satellite radar image which is more suitable for observing long swells. Optical images collected from cameras on-board a ship, over high-ground, or onboard an unmanned auto-piloting vehicle (UAV) may have pixel size that is small enough to resolve decimeter-scale short gravity waves. If diffuse sky light is the only source of lighting and it is uniform in camera-viewing directions, then the image intensity is proportional to the surface reflectance R(x, y) of diffuse light, and R is directly related to the surface slope. The slope spectrum and wave-height spectra S(x, y) may then be derived from R(x, y). The results are compared with the in situ measurement of wave spectra over Keelung Sill from a research vessel. The application of this method is for analysis and interpretation of satellite images on studies of current and wave interaction that often require fine scale information of wave-height spectra S(x, y) that changes dynamically with time and space.

• 한국수소및신에너지학회논문집
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• 제16권3호
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• pp.269-276
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• 2005

Zn, Bi 와 V 금속이온 전구체를 사용하여 모노클리닉 결정구조를 갖는 신규 ZnBiVO4 광촉매를 손쉽게 합성 할 수 있는 방법을 개발하였다. 합성된 $ZnBiVO_4$ 광촉매는 XRD 과 FESEM등을 이용하여 미세구조를 분석하였으며, 분석결과 본 삼성분계 금속산화물 반도체 광촉매는 모노클리닉 결정구조를 갖는 것을 알 수 있었다. 저온 수용액방법에 의해 손쉽게 나노 구조를 갖는 $ZnBiVO_4$가 제조되었으며, 그 광촉매의 최소 입자크기는 20-30 nm 이다. $ZnBiVO_4$ 광촉매는 UV-visible DRS (diffuse reflectance spectroscopy)로 그 띠간격(band gap)을 측정하였으며, FT-IR을 사용하여 구조 및 물질 상의 순도를 확인하였다. 그리고 $H_2S$를 광분해하여 수소를 발생하는($122ml/hr{\cdot}g$) 우수한 광촉매 활성을 보여 주었다.

• Korean Chemical Engineering Research
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• 제54권1호
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• pp.127-134
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• 2016

A series of Ce-doped ZnO (Ce/ZnO) nanostructures were fabricated using the co-precipitation method, then a simply nontoxic hydrothermal approach was proposed for preparation of reduced graphene oxide (rGO)-Ce/ZnO composites. The synthesized composites were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS), UV-vis diffuse reflectance spectroscopy (DRS) techniques and Raman pattern. The as-synthesized rGO-Ce/ZnO composites showed high photodecomposition efficiency in comparison with the rGO-ZnO, Ce/ZnO, pure ZnO under UV, visible-light and sunlight irradiation. The degradation of methylene blue (MB) (10 mg/L, 100ml) by 95.8% within 60 min by using rGO-2 (10 mg) under sunlight irradiation was observed. The repeated use of the rGO-2 was investigated, and the results showed almost no decay in the catalytic activity.