• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
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• pp.146-150
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• 2004

Degradation efficiency of pentachlorophenol (PCP) by using direct UV photolysis and $TiO_2$ photocatalysis was evaluated with both chemical analyses and acute toxicity assessment employing luminescent bacteria Vibrio fischeri. PCP was chosen as a target compound in this study because of its wide application as fungicide, bactericide, insecticide and wood preservative in agriculture and many industries, in addition to its well-known environmental consequences. The acute toxicity to the microbe was reduced by >60% when applying UV alone, and was completely removed when treated with $UV-TiO_2$ combinations. Toxicity reduction pattern determined with the Microtox Assay generally corresponds with the chemistry data: However, it should be noted that toxicity was greater than expected by the chemistry data. Formation of TCBQ, a toxic byprodut, could not explain observed microbial toxicity. These observations are probably due to the presence of unidentified toxic PCP byproducts, which may include polychlorinated dibenzodioxins and polychlorinated dibenzofurans. When Microtox results were compared between different exposure time, i.e.,5 min and 15 min, an interesting pattern was noted with $UVA-\;TiO_2$ treatment. While no microbial toxicity was observed with 5 min exposure, an EC50 value of 45.4% was estimated with 15 min exposure, which was not observed in $UVB-\;TiO_2$ exposure. This result may suggest the presence of unidentified toxic degradation products generated in the later stage of treatment. Based on this study, $TiO_2$ photocatalyst, together with UVB photolysis could improve the removal of both PCP and its toxic derivatives in more efficient way. The Microtox Assay is promising and economical method for monitoring efficiency of wastewater treatment processes.

• 생태와환경
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• 제36권3호통권104호
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• pp.235-241
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• 2003

자외선에 의한 조류기원 용존유기물의 특성변화를 조사하기 위하여 배양한 남조류 두종 (Microcystis aeruginosa, Oscillatoria agardhii)의 체외배출용존유기물에 자외선 처리전과 처리후의 생분해도와 유기물의 화학적조성을 비교하였다. 자외선처리는 pyrex용기에 시료를 넣고 인공자외선램프(UVA: 40 W/$m^2$, UVB: 2 W/$m^2$)로 24시간 조사하였다. 유기물의 화학적조성은 XAD-8, 양이온, 음이온수지를 이용하여 소수성 산 (hydrophobic acids; HoA), 소수성 중성 (hydrophobic neutrals;HoN), 친수성 산 (hydrophilic acids; HiA), 친수성 염기 (hydrophilic bases; HiB), 그리고 친수성 중성 (hydrophilic neutrals; HiN)의 5개 분획으로 분류하였다. 자외선처리동안 유기물의 농도변화는 거의 없었던 반면 생분해도는 자외선처리 전에 비해 현저히 감소하였다(M. aeruginosa: 17%, O. agardhii: 28% 감소). 또한 자외선 처리 전과 후의 유기물의 화학적조성도 상당한 차이를 보였다. 자외선처리 후 HiB분획(단백질, 아미노산류)은 감소한 반면 HiA분획 (카복실산류)은 증가하였다. 유기산분석에서도 3종류의 카복실산이 자외선처리 후 증가하는 것으로 나타났다. 일반적으로 수체의 유기물은 자외선에 의해 난분해성 유기물이 분해되거나 잘게 쪼개져 이분해성 유기물로 전환되는 것으로 알려졌다. 그러나 본 연구에서는 조류기원의 이분해성 유기물의 경우는 자외선에 의해 완전한 광분해는 보이지 않았지만 난분해성 유기물로 전환되었고 화학적조성도 바뀌었다. 이는 유기물의 기원과 종류에 따라 자외선에 대한 영향이 다르다는 것을 시사한다.0.73, P< 0.001). 본 연구기간동안 동물플랑크톤 섭식에 의한 청수기는 관찰되지 않았으며, 동 ${\cdot}$ 식물플랑크톤의 다양성은 식물플랑크톤의 생물량 증가 시 회복되는 것으로 나타났다. 본 연구결과에서는 부영양 호수에서 동물플랑크톤의 섭식이나 제한영양염의 결핍이 식물플랑크톤의 현존량에 영향을 출 수 있으나 군집의 변화를 야기하지는 못함이 제시되었다.X>$NH_4\;^+$, $NO_3\;^-$, $PO_4\;^{3-}$ 및 $SiO_2$의 용출량 범위는 각각 -9${\sim}$ 105 mgN $m^{-2}day^{-1}$, -156${\sim}$62 $m^{-2}day^{-1}$ -5${\sim}$5 $m^{-2}day^{-1}$, 및 12 ${\sim}$ 117 $m^{-2}day^{-1}$였다. 낙동강과 서낙동강에서 식물플랑크톤의 1차 생산성과 조체의 C:N:P의 Redfield 비율 106: 16: 1을 이용하여 추정한결과 저질에서 용출되는 $NH_4\;^+$는 식물플랑크톤의 요구량의 9 ${\sim}$23%이었고, $PO_4\;^{3-}$는 11 ${\sim}$ 22%를 차지하였다.도로 검출되어 이를 고려한정수공정의 관리가 필요하리라 생각된다.$yr^{-1}$)의 71%가 감소되어야 할 필요성이 제기되었다. 또한 여름철 심층 산소 고갈이 야기되었고, 이 시기에 퇴적물로 용출된 인이 식물플랑크톤 성장에 이용될 수 있기때문에 퇴적물에 대한 관리도 수행될 필요가 있다

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.147-148
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• 2009

We have fabricated a down tapered polymer tip on optical fiber end-face by a guided UV light. One side of fiber was aligned with a mercury-xenon lamp and another was put into UV curable polymer. A shape of tip was controlled by adjusting an irradiance of lamp and time of exposure. A bending effect also affects the result. Optical characteristic was achieved preliminarily with solution of minute particles.

• 한국정밀공학회지
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• 제33권10호
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• pp.875-880
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• 2016

In this study, we proposed an effective and simple way to directly generate wrinkle patterns on a curved surface. A curved surface was prepared using a 3D printer and an UV (Ultraviolet)-lighting system was utilized to weakly polymerize the UV-curable thin resin layer coated on the surface, resulting in a gradient of material properties in the layer thickness. Subsequently, a thermal curing process was conducted to generate microscale wrinkles by compressive forces that were generated during complete curing. Wrinkle shapes from 5, 15, 25 sec of UV-light exposure were compared. With increasing UV-exposure, the line-width of wrinkles became thicker due to much higher strength of skin zone. The results indicated that the proposed fabrication process could be utilized for surface modification in diverse research fields.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.338-351
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• 2003

UV radiation is the most dangerous stress factor among permanent environmental impacts on human skin. Consequences of UV exposure are aberrant tissue architecture, alterations in skin cells including functional changes. Nowadays new kinds of outdoor leisure-time activities and changing environmental conditions make the question of sun protection more important than ever. It is necessary to recognize that self-confident consumers do not consider to change their way of life, they demand modern solutions on the basis of new scientific developments. In the past one fundamental principle of cosmetics was the use of physical and organic filter systems against damaging UV-rays. Today new research results demonstrate that natural protecting cell mechanisms can be activated. Suitable biological actives strongly support the protection function not from the surface but from the inside of the cell. A soy seed preparation (SSP) was proven to stimulate natural skin protective functions. The major functions are an increased energy level and the prevention of DNA damage. These functions can I be defined as biological UV protection. The tumor suppressor protein p53 plays a key role in the regulation of DNA repair. p53 must be transferred into the phosphorylated form to work as transcription factor for genes which are regulating the cell cycle or organizing DNA repair. A pretreatment with SSP increases the phosphorylation rate of p53 of chronically UV-irradiated human keratinocytes significantly. According to the same test procedure SSP induces a dramatic increase in the expression of the tumor suppressor protein p14$^{ARF}$ that is supporting the p53 activity by blocking the antagonist of p53, the oncoprotein Mdm2. Mdm2, a ubiquitin E3-ligase, downregulates p53 and at the same time it prevents phosphorylation of p53. The positive influence of the tumor suppressor proteins explains the stimulation of DNA repair and prevention of sunburn cell formation by SSP, which was proven in cell culture experiments. In vivo the increased skin tolerance against UV irradiation by SSP could be confirmed too. We have assumed, that an increased repair potential provides full cell functionality.y.

• 한국안광학회지
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• 제20권2호
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• pp.237-246
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• 2015

목적: 본 연구는 안구에 존재하는 항산화효소인 superoxide dismutase(SOD)와 catalase(CAT)가 UV-B에 반복적으로 노출되었을 때 유발되는 구조변성 및 활성저하의 상관관계를 밝히며, 자외선 차단 RGP렌즈의 사용으로 효소의 변성과 활성저하가 효율적으로 차단되는가를 알아보기 위하여 수행되었다. 방법: SOD와 CAT의 표준품으로 각각의 효소용액을 제조하고 하루 30분, 1시간 및 2시간씩 312 nm의 UV-B에 1, 2, 3, 4 및 5일 동안 반복적으로 노출시켰다. 이 때 UV-B에 직접 노출시킨 항산화효소의 구조 및 활성변화를 자외선 차단기능이 있는 RGP렌즈로 UV-B를 차단시킨 경우와 비교하였다. UV-B 반복노출에 따른 SOD와 CAT의 구조변성은 전기영동분석으로 확인하였으며, 이들 효소활성은 분석키트를 이용하여 비색분석법으로 측정하였다. 결과: UV-B에 반복노출된 SOD는 일일 30분 조사조건으로 반복노출되었을 때에도 전기영동분석에서 효소다중화(polymerization)가 관찰되었으나 활성의 변화는 10% 이내로 나타났다. 반면 UV-B에 반복노출된 CAT은 전기영동 시 효소밴드크기나 진하기가 감소하여 구조변성이 나타났음을 확인할 수 있었으며, 반복노출시간이 긴 경우 CAT은 전기영동분석에서 효소밴드를 보임에도 불구하고 그 활성은 완전히 소실되었다. 또한 UV-B 조사로 인한 CAT의 변성은 63.7%의 UV-B 차단기능을 가진 RGP렌즈의 사용으로 어느 정도 억제되었으나 완전히 억제되는 것은 아니었다. 결론: 이상의 결과로 UV-B 반복노출에 따른 항산화효소의 구조변성은 그 종류에 따라 효소활성의 감소정도와 반드시 일치하는 것은 아님을 알 수 있었다. 따라서 자외선으로 인한 항산화효소의 손상을 막기 위하여서는 콘택트렌즈를 착용한 상태에서 자외선 노출시간을 최소화하거나, FDA Class I 차단제에 해당하는 UV 차단율을 가지는 콘택트렌즈를 착용 또는 이에 상응하는 UV차단율을 가지는 선글라스를 덧착용할 것을 권장한다.

• Journal of Information Display
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• 제7권2호
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• pp.6-11
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• 2006

New photopolymers were designed and prepared using the photosensitive polymer binders. Holographic gratings were successfully fabricated in these photopolymer samples by a conventional optical interference method. We also investigated the effect of photocrosslink in the polymer binder on the diffraction behavior of a new photopolymer. The dynamic behavior of the grating formation was monitored by changing exposure intensity in terms of the diffraction efficiency. Particularly, we focused our efforts in observing the variation of diffraction efficiency during a post UV curing process. The surface topographical change of photopolymer layer before and after Vis/UV light exposure was observed by atomic force microscope (AFM). We inscribed the gratings of the glass diffuser on the surface of the photopolymer and investigated their diffusing properties. The diffusers with photopolymer with the main chain polymer binder showed relatively good viewing angle of around ${\pm}30{\circ}$. Two kinds of photopolymer showed similar uniformity of around 47-54%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.358-361
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• 2001

A new photoalignment material PMI5CA, poly{N-(phenyl)maleimide-co-3-[4-(pentyloxy) cinnamate]propyl-2-hydroxy-1-methacrylate}, was synthesized and the electra-optical (EO) characteristics in the vertical-aligned (VA) liquid crystal display (LCD) photo-aligned on the photopolymer surface were studied. Excellent voltage-transmittance(V-T) characteristics in the VA-LCD photoaligned with polarized UV exposure of oblique direction on the pohotopolymer surfaces for 1 min can be achieved. The transmittance of the VA-LCD photoaligned on the photopolymer surface decreased with increasing UV exposure time. We suggest that the decrease of transmittance in the VA-LCD photoaligned on the photopolymer surface is attributed to the dissociation of the ester linkage in the photodimerized cinnamate structure with increasing UV exposure time

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.185-188
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• 2005

We synthesized the two types of photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the two types of photopolymer surface can be obtained. The Voltage-transmittance (V-T) curve in the photoaligned TN cell with UV exposure was different from two type. The response time of photoaligned TN cell was measured about 21 ms in two alkyl chain and about 15ms in four alkyl chain.

• 한국재료학회지
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• 제33권3호
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• pp.87-94
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• 2023

Exposure to ultraviolet (UV) light is often associated with skin damage, sometimes very serious, and in recent times has received particular attention as a health risk. As a result, the proper use of sunscreen has long been recommended to protect against skin damage. The continued increase in the use of sunscreen may be linked to increased information about the risk of melanoma and non-melanoma skin cancer caused by prolonged exposure to ultraviolet rays. Natural and harmless materials that block and prevent UV light have emerged as essential household items in the field of skin beauty. New materials need to be considered and evaluated in relation to ultraviolet rays and their harmful effects. This study aims to explain the effect of UV exposure on human skin, the classification of sunscreens, the application of zeolite, nano clay, and LDH in sunscreen formulations, as well as the regulation of this service in various countries around the world.