• 한국세라믹학회지
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• 제39권8호
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• pp.750-757
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• 2002

Photosensitive sol solution을 이용한 self pattern된 박막은 photoresist/dry etching process에 비해 박막의 제조과정이 간단하다는 장점을 가지고 있다. 이 연구에서는 photosensitive sol solution을 이용하여 spin coating법에 의해 $Sr_{0.9}Bi_{2.1}Ta_2O_9$의 조성을 갖는 강유전체 박막을 제조하였으며 출발원료는 $Sr(OC_2H_5)_2,\;Bi(TMHD)_3$와 $Ta(OC_2H_5)_5$를 사용하였다. SBT 박막에 UV 노광시간을 증가시킴에 따라 M-O-M 결합이 생성되면서 metal ${\beta}$-diketonate의 UV 흡수 피크 강도는 감소되었고 SBT 박막에 UV 조사에 따른 용해도 차이가 생기면서 fine patterning을 얻을 수 있었다. 또한 UV가 조사된 SBT 박막의 강유전 특성이 UV가 조사되지 않은 것보다 우수하였다.

• 분석과학
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• 제13권2호
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• pp.234-240
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• 2000

수질계의 부식산을 화학적 산화처리하기 위한 방법의 하나로 광산화공정을 도입하여 부식산의 특성 변화를 조사하였다. 광산화공정은 UV단독, UV/$TiO_2$ 및 UV/$H_2O_2$ 시스템을 실험하였다. UV 단독 조사시 TOC 제거율은 pH 7-9에서 가장 높았으며, 흡광도는 강알카리성 영역에서 감소율이 향상된 결과를 보였다. 각 시스템별로 처리도를 보면, UV/$TiO_2$ 시스템의 경우 $TiO_2$ 의 농도가 50ppm 일때 TOC 제거와 흡광도 감소의 효율이 높았으며 50ppm 이상을 투입해도 처리율에 변화가 없었다. UV/$H_2O_2$ 시스템에서는 과산화수소의 농도가 20mM이 최적의 주입농도로 조사되었으며, 그 이상 투입할 경우 TOC와 흡광도의 처리율이 저하되었다. 탄산이온을 첨가할 경우, TOC 제거율 및 UV 흡광도의 감소율 모두 감소하며, TOC 제거율이 흡광도 감소율에 비해 상대적으로 더 크게 나타났다.

• Tribology and Lubricants
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• 제32권3호
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• pp.75-81
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• 2016

Future electronics such as electronic paper and foldable cellphone are required to be flexible and transparent and should have a high performance. In order to fabricate the flexible electronics using flexibility transfer process, techniques for transferring various devices from rigid substrate onto flexible substrate by elastomeric stamp, have been developed. Adhesion between the elastomeric stamp and various devices is crucial for successful transfer process. The adhesion can be controlled by the thickness of the stamp, separation velocity, contact load, and stamp surface treatment. In this study, we fabricated the bump shape stamp consisting of a UV-curable polymer and investigated the effects of curing condition, separation velocity, and contact load on the adhesion characteristics of bumps. The bumps with hemispherical shape were fabricated using a dispensing process, which is one of the ink-jet printing techniques. Curing conditions of the bumps were controlled by the amount of UV irradiation energy. The adhesion characteristics of bumps are evaluated by adhesion test. The results show that the pull-off forces of bumps were increased and decreased as UV irradiation energy increased. For UV irradiation energies of 300 and 500 mJ/cm², the pull-off forces were increased as the separation velocity increased. The pull-off forces also increased with the increase of contact load. In the case of UV irradiation energy above 600 mJ/cm², however, the pull-off forces were not changed. Therefore, we believe that the bump shape stamp can be applied to roll-based transfer process and selective transfer process as an elastomeric stamp.

• 환경위생공학
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• 제15권4호
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• pp.27-27
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• 2000

In order to treat the dyeing wastewater, the UV/TiO₂/H₂O₂ system was investigated, and proper pretreatment methods were examined to reduce the load on the system considering economical and technical efficiency. The results of this study were as follows: 1.UV/TiO₂/H₂O₂ system with pretreatment process was adopted, the result of Chemical coagulation and pH control units was pH 11→ coagulation → pH 4 and the optimum dosage of FeCl₃ was 600㎎/ℓ 2. Proper dosage of TiO₂in the UV/TiO₂/H₂O₂ system with pretreatment process was 2g/ℓ and H₂O₂ was 1000㎎/ℓ, UV contact time was 20min to get below 200㎎/ℓ of $COD_{Cr}$

• 환경위생공학
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• 제15권4호
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• pp.26-34
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• 2000

In order to treat the dyeing wastewater, the $UV/TiO_2/H_2O_2$ system was investigated, and proper pretreatment methods were examined to reduce the load on the system considering economical and technical efficiency. The results of this study were as follows: 1. $UV/TiO_2/H_2O_2$ system with pretreatment process was adopted, the result of Chemical coagulation and pH control units was $pH{\;}11{\;}{\rightarrow}{\;}coagulation{\;}{\rightarrow}{\;}pH{\;}4$ and the optimum dosage of $FeCl_3$ was $600mg/{\ell}$. 2. Proper dosage of $TiO_2$ in the $UV/TiO_2/H_2O_2$ system with pretreatment process was $2g/{\ell}$ and $H_2O_2$ was $1000mg/{\ell}$, UV contact time was 20min to get $200mg/{\ell}$ of $COD_{Cr}$.

• 한국염색가공학회지
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• 제20권4호
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• pp.8-14
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• 2008

Flame-retardant cotton fabrics were prepared by UV curing of photocurable aqueous formulations of phosphorous-containing methacrylate monomers and 2-hydroxy-2-methyl-1-phenyl-1-propanone as flame retardants and a photoinitiator respectively, which is an environmentally friendly and energy-saving process. The characterization of the UV-coated cotton fabric was made by ATR, TGA and limited oxygen index measurement. UV cured coating onto cotton fabrics reduced the first thermal decomposition temperature and mass loss as well as increase in the amount of char residue compared with the untreated cotton fabric presumably due to modified thermal decomposition process. The LOI values up to 28.5 and 27.2 were obtained by the UV curing of MMEP and TMEP respectively. The treatment was durable to five laundering cycles, which was more prominent in the case of trifunctional TMEP treatment.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.107-109
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• 1993

Non-enzymatic glycosylation and fragmentation of collagen molecule were investigated by irradiating Ultraviolet A(UV-A) with or without scavengers of reactive oxygen species (ROS) in the presence of glucose. Non-enzymatic glycosylation was increased by UV-A at high concentration of glucose. It was reduced in the presence of the scavengers of superoxide radical and singlet oxygen, but not reduced in the presence of hydroxy radical scavenger. Fragmentation of collagen was increased by UV-A, but it was decreased in the presence of all ROS scavengers tested. Superoxide radical and singlet oxygen produced by autoxidation of glucose without UV-A may encounter the initial phase of glycosylation. Data presented here suggest that UV-A affects only on the fragmentation process, but all ROS except hydroxy radical act on both processes. It appears that hydroxy radical does not act on the glycosylation process.

• 한국의류학회지
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• 제45권6호
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• pp.1052-1062
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• 2021

This study aims to confirm the possibility of Ultra-Violet (UV)-printed 3D printing materials using thermal polyurethane (TPU) with CMYK colors by applying an eco-friendly UV digital printing process. A UV-printed 3D printing TPU material was prepared with cycles of UV printing and CMYK colors. Dyeability of the 3D TPU samples with cycles of UV printing and CMYK were analyzed for thickness, weight, surface roughness, reflectance, colorimetry, and K/S values. The thickness and weight of 3D-printed TPU samples with cycles of UV printing are increased with overprints from 1 to 5. The surface roughness of 3D-printed TPU samples with increasing UV prints were decreased, meaning that the surface of TPU samples becomes gradually smoother. The reflectance spectra of CMYK UV-printed TPU samples showed the surface reflectance within each characteristic wavelength of CMYK. The 3D-printed TPU samples, subjected to UV printing twice or more, showed low surface reflectance. After examining the L^*a^*b^* of the 3D-printed TPU samples by the cycles of UV printing, the study found that the more UV got printed more than 2 times, the closer the color to each CMYK.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.499-500
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• 2007

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.91-94
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• 2005

With increasing demands for large-scale micro-optical components in the field of digital display, the establishment of large-scale fabrication technology fur polymeric patterns has become a priority. The starting point of any polymer replication process is the mold, and the mold often has flat surface. However, It is very hard to replicate large-scale micro patterns using the flat mold, because the cost of large-scale flat mold was very high, and some uniformity and releasing problems were often occurred in large scale flat molding process. In this study, a UV roll imprinting system to overcome the financial and fabrication issues of large-scale pattern replication process was designed and constructed. As a practical example of the system, a lenticular lens with radius of curvature of $223{\mu}m$ and pitch of $280{\mu}m$, which was used to provide wide viewing angle in projection TV, was designed and fabricated. The roll stamper was fabricated using direct machining process of aluminum roll base. Finally, the shape accuracy and uniformity of roll imprinted lenticular lens sheet were measured and analyzed.