• 한국염색가공학회지
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• 제23권2호
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• pp.76-82
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• 2011

Ultra High molecular weight polyethylene(UHMWPE) films were photooxidized by UV/ozone irradiation. Reflectance of the irradiated films decreased in the low wavelength regions of visible light, indicating destructive interference of visible light due to roughened surface. The UV treatment developed the nano-scale roughness on the UHMWPE films surface, which increased by two-fold from 82.6 to 156.6nm in terms of peak-valley roughness. The UV irradiation caused the oxygen content of the UHMWPE film surface to increase. Water contact angle decreased from $83.2^{\circ}$ to $72.9^{\circ}$ and surface energy increased from 37.8 to 42.6mJ/$m^2$ with increasing UV energy. The surface energy change was attributed to significant contribution of polar component rather than nonpolar component indicating surface photooxidation of UHMWPE films. The increased dyeability to cationic dyes may be due to the photochemically introduced anionic and dipolar dyeing sites on the film surfaces.

• 생명과학회지
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• 제31권10호
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• pp.905-912
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• 2021

본 연구에서는 4가지 일반적인 식중독 병원균인 Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Bacillus subtilis에 대해 270 nm UV C-LED, 365 nm UV A-LED, 465~475, 620~630 nm visible-LED, 850, 5,000~7,000 nm infrared-LED를 조사하여 각 세균의 성장에 미치는 영향을 조사 하였다. 270 nm UV C-LED의 경우, 10 min 또는 30 min 조사 시 4가지 균주 모두 대조구에 비해 억제 효과를 나타냈다. 또한 365 nm UV A-LED를 1시간 또는 3시간 조사한 경우 B. subtilis의 100% 생장 억제를 보였다. 465~475 nm visible-LED를 1시간 조사한 경우, 4 종류 균주 모두 대조구과 유의 한 차이가 없었으며, 3시간 조사 시 유의한 성장 억제를 보였다. 620~630 nm visible-LED를 처리한 S. aureus와 B. subtilis, 850 nm infrared-LED를 처리한 S. typhimurium과 S. aureus, 5,000~7,000 nm infrared-LED를 처리한 E. coli, S. typhimurium 및 S. aureus는 각각 대조구에 비해 증식되는 것으로 확인되었다. 이에 따라 다양한 LED 광원의 사용을 통해 식중독 미생물의 억제 및 증식 효과를 확인한 바, 다양한 LED 광원의 파장 특성을 이용한 식품 보존과 응용 기술로서의 잠재력이 있음을 시사한다.

• 한국산학기술학회논문지
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• 제11권5호
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• pp.1760-1767
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• 2010

FAT복합체는 TOS ($TiOSO_4{\cdot}xH_2O$)를 사용하여 솔-겔 방법으로 제조한다. 시료들은 SEM, 비표면적, XRD 및 EDX를 사용하여 분석하였다. SEM결과로서 Fe 와 $TiO_2$ 입자가 AC 표면에 분포하고 있다. XRD 결과에서 Fe-AC/$TiO_2$ 복합체는 다 anatase결정상을 하고 있다. 그리고 EDX 결과에서 C, O, Ti 및 Fe 원소가 Fe-AC/$TiO_2$ 복합체에 다 존재하고 있다. 복합체의 광촉매 활성은 가시광선과 UV광선을 사용하고 메틸렌불루(MB)의 분해 효과에 의해 측정한다. Fe-AC/$TiO_2$ 복합체는 강한 가시광선 조사에서 우수한 광촉매 효과가 나타난다. AC/$TiO_2$ 복합체에 있는 소량 존재하는 Fe 원소가 그들의 광촉매 활성을 강화할 수 있다.

• 한국광학회지
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• 제34권6호
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• pp.283-288
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• 2023

본 연구에서는 quartz, sapphire, slide glass와 같이 투명한 기판 위에 (3-mercaptopropyl) trimethoxysilane (MPTMS)를 처리하고 나노미터 두께로 은을 증착하여 형성된 은 나노 박막의 광학적, 전기적 특성을 탐구한다. 기판의 MPTMS 증착에 따라 각각 5, 7, 9, 13 nm 두께를 갖는 은 나노 박막의 표면 형태 변화를 전자현미경을 통해 확인하고, UV-visible 전자기파 영역의 투과 측정 실험을 통해 금속 나노 박막에서 나타나는 국소 표면 플라즈몬에 의한 흡수 효과가 줄어드는 것을 확인하였다. 이는 MPTMS에 의해 나노미터 두께의 금속 박막이 균일하게 형성된 것을 의미한다. 또한 MPTMS 증착 시간을 30분부터 77시간까지 조절함으로써 UV-visible 투과율과 전기전도도 변화를 측정하여 균일한 금속 나노 박막 형성을 위한 MPTMS의 증착 조건에 대해 탐구한다. 본 연구 결과는 투명 기판 위 균일한 금속 나노 박막 형성에 대한 연구 및 고성능 나노 박막 전극 개발 등과 같은 응용 분야에 도움이 될 것이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.373-373
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• 2012

We fabricated conductive zinc oxide (ZnO) thin film at low temperature by UV-enhanced atomic layer deposition. The atomic layer deposition relies on alternate pulsing of the precursor gases onto the substrate surface and subsequent chemisorption of the precursors. In this experiment, diethylzinc (DEZ) and $H_2O$ were used as precursors with UV light. The UV light was very effective to improve the conductivity of the ZnO thin film. The thickness, transparency and resistivity were investigated by ellisometry, UV-visible spectroscopy and Four-point probe.

• 한국물환경학회지
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• 제26권4호
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• pp.707-712
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• 2010

Nitrogen-doped $TiO_2$ particles have been successfully prepared using titanium tetraisopropoxide as the Ti source and urea as the nitrogen source. As-prepared nitrogen-doped $TiO_2$ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and ultraviolet-visible light (UV-vis) absorption spectra techniques. Photocatalytic degradation of Methylene Blue (MB) has been carried out in both solar light (UV-vis) and the visible region (${\lambda}=420nm$). Nitrogen-doped $TiO_2$ exhibits higher activity than the commercial $TiO_2$ photocalyst, particularly under visible-light irradiation because bandgap of nitrogen-doped $TiO_2$ becomes remarkably decreased.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.61-64
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• 2012

The ultraviolet and visible light responsive properties of the amorphous indium gallium zinc oxide thin film transistor have been investigated. Amorphous indium gallium zinc oxide (a-IGZO) thin film transistor operate in the enhancement mode with saturation mobility of $6.99cm^2/Vs$, threshold voltage of 13.5 V, subthreshold slope of 1.58 V/dec and an on/off current ratio of $2.45{\times}10^8$. The transistor was subsequently characterized in respect of visible light and UV illuminations in order to investigate its potential for possible use as a detector. The performance of the transistor is indicates a high-photosensitivity in the off-state with a ratio of photocurrent to dark current of $5.74{\times}10^2$. The obtained results reveal that the amorphous indium gallium zinc oxide thin film transistor can be used to fabricate UV photodetector operating in the 366 nm.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.298-300
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• 2004

An alternative molecular porphyrin-phthalocyanine aggregate was prepared and characterized with UV-visible and X-ray absorption spectroscopies. UV-visible experiments evidence 1-dimensional porphyrin-phthalo-cyanine array formed by mixing $SnTPPCl_2 ({\lambda}_{max}=429,\;{\varepsilon}=2.4{\times10^ 5 /M{\cdot}cm)\;and\;NiPc(OBu)_8({\lambda}_{max}=744 nm,\;{\varepsilon}= 2.0{\times}10^ 5 /M{\cdot}cm)$ in solution. In the UV-visible spectrum of the porphyrin-phthalocyanine array, $(SnPNiPc)_n$, a new Q-band appeared at 844 nm with decrease of the Q-band peak of $NiPc(OBu)_8$ at 744 nm. The red-shift of Q-band evidences an alternative porphyrin-phthalocyanine array formed in solution through metal-halide interaction rather than ${\pi}-{\pi}$ facial interaction, in which nickel of $NiPc(OBu)_8$ coordinates with chloride of $SnTPPCl_2$ through self assembly. Ni K-edge XANES (X-ray absorption near edge structure) spectra also support the axial ligation of nickel to chloride. The square planar structure of $NiPc(OBu)_8$ turns to an octahedral structure in (SnPNiPcSnP) by axial ligation. A higher energy-shift (0.2 eV) of the preedge peak of (SnPNiPcSnP) indicaties partial oxidation of nickel by charge transfer from NiPc$(OBu)_8$ to SnTPPCl$_2$.

• 한국재료학회지
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• 제19권10호
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• pp.555-561
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• 2009

Expanded graphite (EG) is synthesized by chemical intercalation of natural graphite (NG) and rapid expansion at high temperature, with titanium n-butoxide (TNB) used as titanium source by a sol-gel method to prepare EG-TiO$_2$ composite. The performances of the prepared EG-TiO$_2$ composite are characterized by BET surface area measurement, scanning electron microscopy (SEM), X-ray diffraction patterns (XRD) and energy dispersive X-ray analysis (EDX). To compare the photocatalytic activities of the EG-TiO$_2$ composite, three kinds of dye solutions, methylene blue (MB), methylene orange (MO) and rhodamine B (RhB), and two kinds of light source, UV light and visible light (VL), are used. Comparing the results, it can be clearly seen that the degradation of all of the dye solutions under irradiation by UV light is much better than that under irradiation by visible light, and the decomposition of MB solution was better than that of both of MO and RhB solution.

• E2M - 전기 전자와 첨단 소재
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• 제8권4호
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• pp.458-463
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• 1995

The optical and electrical properties of $C_{22}$-Quinolinium(TCNQ) Langmuir-Blodgett films have been studied depending on the annealing temperatures. The optimal properties were investigated using UV/visible(300-800[nm]) absorption spectra and FTIR(Fourier-transformed- infrared) absorption measurements. The electrical properties were investigated in a frequency range of 10[Hz]-13[MHz]. The UV/visible absorption spectra at room temperature show that there are four characteristic peaks at 320, 380, 494 and 678[nm]. These absorption peaks decrease very rapidly above the annealing temperature of 180[.deg. C], which is due to a structural change of TCNQ. The FTIR absorption measurements strongly support the result of the UV/visible absorption spectra, because the absorption peak of TCNQ- at 2181[$cm^{-1}$ /] also decreases above 140[.deg. C]. The frequency-dependent dielectric constant shows that there is a dielectric dispersion near 1[MHz] which is due to an orientational polarization of the molecules inside the film. The overall frequency-dependent dielectric constant is higher near 80[.deg. C]. It may be due to a softness of the alkyl chains.s.