• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.251-252
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• 2008

• Korean Journal of Remote Sensing
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• v.29 no.3
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• pp.325-329
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• 2013

This present study describes an application of UV scanning spectrometer $O_4$ data for retrieval of aerosol vertical profiles in Seoul during the measurement period that includes two Asian dust event days. The results show large variations of aerosol load in vertical and temporal scales. Large variations in aerosol were observed at 1 km in height during the daytime in the measurement period when the Asian dust events took place. The aerosol load, however, was found to be largest at the surface compared to those retrieved at the higher atmospheric layers. The results also clearly identified the diurnal patterns of aerosol vertical distributions. The aerosol load was high in the morning and noon whereas it was low in the afternoon. This study demonstrates that UV scanning spectrometer observations of the oxygen dimer can serve as a potential method for determination of atmospheric aerosol vertical distributions and optical properties.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.321-327
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• 2022

In this paper, a wrinkled structure was formed on the PDMS surface through UV/Ozone treatment, and the wrinkle structure formation mechanism was revealed through physicochemical characterization. A wrinkle structure was formed on the PDMS surface through UV/Ozone treatment for 30 min, and periodic wrinkle formation on the PDMS surface was confirmed by cross-sectional imaging of the scanning electron microscope. In addition, through x-ray photoelectron spectroscopy spectral analysis, it was confirmed that the silica-like-surface of SiOx on the PDMS surface was formed by UV/Ozone. The results of this study not only improve the understanding of the mechanism of wrinkle structure formation on the PDMS surface by UV/Ozone treatment, but also can be used as a basic study to adjust the amplitude and period of the wrinkle structure according to UV/Ozone irradiation conditions in the future.contact angles and the surface energies of FSAMs, it was confirmed that pretilt angles of LC molecules increased according to the alkyl chain length. High optical transparency and uniform homeotropic LC alignment characteristics of FSAMs showed the possibility of FSAMs as an LC alignment layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.132-136
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• 2004

열 증착 방법을 이용하여 copper(II)-phthalocyanine(CuPc) 박막을 glass 기판 위에 제작하였다. 열처리 조건은 $150^{\circ}C$에서 후열(annealing) 처리 하는 방식과 예열하는 두 가지 방식으로 달리하였다. 제작된 박막의 전기전도도를 평가하기 위해 마이크로웨이브 근접장 효과를 이용한 근접장 현미경(near-field scanning microwave microscope)을 이용하여 비파괴적인 방식으로 CuPc 박막의 반사계수(reflection coefficient)를 측정하였다. CuPc 박막의 전기전도도 특성을 UV 흡수도를 통한 에너지 밴드갭의 shift 현상과 관련지어 설명하고 또한 x-ray diffraction(XRD) data를 통해 박막의 결정 특성과 비교하였다. 박막 표면 특성은 SEM(scanning microscope microscopy)을 통해 관측하였다. 열처리 조건에 따른 CuPc 박막의 전기전도도 특성은 후열 처리한 박막의 경우 예열 처리한 박막보다 전기 전도 특성이 향상되었음을 관측할 수 있었다.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.84-92
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• 2021

Purpose: The purpose of this study was to compare the dimension safety evaluation between a general ultrasonic cleaner and an ultrasonic cleaner equipped with UV-C (ultraviolet-C). Methods: An edentulous model was prepared. A denture base and an occlusal rim were fabricated, and scanning was performed. After scanning, a denture base and full arch artificial teeth were designed. The full arch artificial teeth were printed using a three-dimensional printer (n=10). The residual resin was washed with alcohol and then scanned (reference data). The printed specimens were classified and cleaned using a general ultrasonic cleaner (GU group) and an ultrasonic cleaner equipped with UV-C (UC group). After each washing, a rescan was performed (scan data). Reference data and scan data were superimposed using overlapping software. Data were statistically analyzed using the Mann-Whitney test (α=0.05). Results: In the deviation values of full arch artificial teeth, the GU group showed a high deviation of 18.02 ㎛ and the UC group showed a low deviation of 15.02 ㎛. The two groups demonstrated a statistically significant difference (p<0.05). Conclusion: Full arch artificial teeth prepared using photopolymerized resin were deformed according to the temperature of water generated in the ultrasonic cleaner. It is judged that there is no deformation according to the UV-C ultrasonic cleaner.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.171-179
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• 2004

Micro-stereolithography technology has made it possible to fabricate a freeform 3D microslructure. This technology is based on conventional stereolithography, in which a UV laser beam irradiates the open surface of a UV-curable liquid photopolymer, causing it to solidify. In micro-stereolithography, a laser beam of a few $\mu m$ diameter is used to solidify a very small area of the photopolymer. This is one of the key technological elements, and can be achieved by using a focusing lens. Thus, the solidification phenomena of the liquid photopolymer must be carefully investigated. In this study, the photopolymer solidification phenomena in response to variations in the scanning pitch of a focused laser beam was investigated experimentally. The effect of layer thickness on the solidification width and depth was also examined. These studies were conducted under the conditions of relatively lower laser power and relatively higher scanning speed. Moreover, the photopolymer solidification phenomena for the relatively higher laser power and lower scanning speed was investigated, too. In this case, comparing to the case of lower laser power and higher scanning speed, the photopolymer absorbed large amount of irradiation energy of the laser beam. These results were compared with those obtained from a photopolymer solidification model. From these results, a new laser-scanning scheme was proposed according to the shape of the 3D model. Samples by each method were fabricated successfully.

• Analytical Science and Technology
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• v.21 no.6
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• pp.553-561
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• 2008

$CNT/TiO_2$ composites were prepared by using multiwall carbon nanotubes (MWCNT) and various titanium alkoxide precursors. The composites were comprehensively characterized by scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and UV-vis absorption spectroscopy. The photoactivity of the prepared materials under UV irradiation, was tested using the conversion of MB from model aqueous solution. Finally, according to the results of methylene blue (MB) removal experiment, we could see that sample CTOS have better MB removal effect than samples CTIP and CTPP.

• Journal of the Korean Society of Costume
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• v.28
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• pp.205-212
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• 1996

This paper is to study the characteristics of fabrics dyed with astringent unripe persimmon juice. The cotton silk rayon and nylon fabrics were dyed with astringet unripe persimmon juice. The structures of natural fabrics dyed fabrics and dyed fabrics followed by washing were examined by scanning electron mi-croscopy. Surface reflexibility of VIS trans-mittance of UV VIS and NIR were analyzed. The study conclues as follows: 1. Colour of cotton fabrics dyed with persim-mon juice became darkended as a function of exposing time to sunlight. That colour was chaged after washing. 2. Blocking effect of ultraciolet light and visible ray was increased in all dyed fabrics. Especially dyed cotton fabric blocked UV light perfectly and the blocking effect was still remained after 9 washings. 3. Persimmon juice dyeing produced coating effect to fabrics besides dyeing effect accord-ing to the scanning electron micrographs. In a word the cotton fabric dyed with per-simmon juice has blocking effect of UV light stiffness. Therefore I think persimmon juice dyeing is a very useful textile finishing and ex-pect a wide application of the technique in fu-ture.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.455-455
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• 2013

$CeO_2$ nanorings were synthesized by using a surfactant free hydrothermal method. The surface morphology, structural and optical properties of the synthesized $CeO_2$ was investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV) spectroscopy measurements. SEM images showed that the surface morphology of the formed $CeO_2$ appeared as nanorings. The XRD pattern of $CeO_2$ nanorings showed the presence of the polycrystalline $CeO_2$ phase readily indexed to the cubic fluorite structure of the $CeO_2$. The mean crystallite size of the $CeO_2$ was calculated using the Scherrer equation from the XRD line broadening of the (111) planes of the cubic $CeO_2$. The UV-Visible spectroscopy spectrum of the $CeO_2$ nanorings exhibited a strong UV absorption band around 350 nm.

• Transactions of Materials Processing
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• v.14 no.5 s.77
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• pp.477-481
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• 2005

Wafer scale micro mirror array with high surface quality for small form factor (SFF) optical pick-up was fabricated by micro UV-molding. To replicate micro mirror array for SFF optical pick-up, a high- precision mold was fabricated using micro-machining technology. Wafer scale micro mirror array was UV-molded using the mold and then the process was optimized experimentally. The surface flatness and roughness of UV-molded micro mirror array were measured by white light scanning interferomety system and analyzed the transcribing characteristics. Finally, the measured flatness of UV-molded micro mirror away for SFF optical pick-up, which was fabricated in the optimum processing condition, was less than 70nm.