• Title/Summary/Keyword: UV resistance

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A Study on Properties of UV-Curing Silver Paste for Touch Panel by Photoinitiator Characteristic (광개시제 특성에 따른 터치 패널용 UV 경화형 Ag 페이스트의 물성 연구)

  • Nam, Su-Yong;Koo, Yong-Hwan;Kim, Sung-Bin
    • Journal of the Korean Graphic Arts Communication Society
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    • v.29 no.2
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    • pp.1-13
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    • 2011
  • The recent spotlight on electronic touch-screen display, a rapid breakthrough in the information society is evolving. Touch panel input device such as a keyboard or mouse without the use of, the on-screen character or a specific location or object on the person's hand touches a particular feature to identify the location of a panel is to be handled. The touch screen on the touch panel is used in the Ag paste is used mostly for low-curable paste. The thermal-curing paste according to the drying process of thermal energy consumption and improve the working environment of organic solvents have problems. In this study, Ag paste used in the non-thermal curing friendly and cost-effective UV curable paste was prepared. Current commercially available thermal-curable binder, was used instead of the flow characteristics of UV-curable oligomers and monomers with functional groups to give a single conductive Ag paste with the addition of a pattern could be formed. Ag paste as a result, thermal-curing adhesive, hardness, resistance and excellent reproduction of fine patterns and was available with screen printing environmentally friendly could see its potential as a patterning technology.

A Fundamental Study on Polymer/Metal Additive Method using a UV Laser for Consumer-oriented 3D Helmet Products (소비자 지향 3차원 헬멧제품 제작을 위한 UV레이저 기반의 폴리머/금속적층에 대한 기초연구)

  • Kang, Bo-Seok;Ahn, Dong-Gyu;Shin, Bo-Sung;Shin, Jong-Kuk
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.6
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    • pp.89-94
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    • 2016
  • Consumer orientation requires that companies understand consumer needs and produce products that meet their expectations. This study proposes a new additive method that creates a polymer/metal bonding layer and thus can lighten the weight of helmets to develop a consumer-oriented 3D printing helmet. The composite solution is experimentally prepared with copper formate and a photopolymer resin. Stereolithography apparatus and photothermal reactions are introduced to fabricate an adhesive hybrid layer of copper metal and polymer. A UV pulse laser with a 355 nm wavelength was installed to simplify this process. Resistance, adhesion, and accuracy were investigated to evaluate the properties of the layer produced.

Influence of Molecular structure of Lubricants on the UV-absorption Characteristics of the Base Wax-pigment Composites (윤활제의 분자구조가 Base Wax-pigment Composite의 UV-absorption특성에 미치는 영향에 관한 연구)

  • Kim, Sung-Hwan
    • Journal of the Korean Applied Science and Technology
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    • v.2 no.2
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    • pp.47-53
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    • 1985
  • Correlation among the wax-pigment composites which is base vehicles for the crepas was investigated in terms of fadeness. The base wax synthesized and pigments are compounded with petroleum lubricant and exposed under carbon arc individually. The yellowing phenomenon was appeared on the reference papers coated with the spindle oil which was then exposed. The papers were again extracted with distilled water and pH of them were ranged between 6.2-6.5. Color difference from Adam-Nickerson equation, ${\vartriangle}E$ of base wax is 0.15 and that of spindle oil are varied from 0.66 to 15.62. Since the main components of the petroleum lubricant are aromatic hydrocarbons which have absorptions characteric of UV ranging from 240 to 280 nm, fadeness characteristics of the composites are largely depend upon the change of molecular structure of spindle oil by absorbing UV. Thus the spindle oil having the following physical properties has the better resistance of fadness and is recommended to use in compounding the base wax-pigment composites: ${\cdot}$ main component: paraffinic hydrocarbon ${\cdot}$ pour point: below - $15^{\circ}C$ ${\cdot}$ UV absorption characteristics: ${\lambda}max.$ : 268-290nm ${\cdot}$ absorbancy: below 0.1(0.03ml of sample/50ml of $CHCl_3$)

Induction and Chatacterization of pKM101 Mutants in Salmonella typhimurium (Salmonella typhimurium내로의 pKM101 돌연변이체의 유도와 그 특성에 관한 연구)

  • 백형석;강수형;이세영
    • Korean Journal of Microbiology
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    • v.20 no.2
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    • pp.89-97
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    • 1982
  • Mutants of plasmid pKM101 modified to enhance mutagenesis were induced and characterized in Salmonella typhimurium. The pKM101 mutant plasmid were transferred normally and stably maintained in cells. They had modified in their ability (i) to enhance the reversion of both point and frameshift mutations, (ii) to protect the cell against UV-irradiation and chemical mutagen treatment, (iii) of ampicillin resistance. A similar modification in enhancement of reversion was also observed in a $uvrB^-$ strains. These results indicated that mutator effect of pKM101 was coded by one plasmid gene.

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Selective Emitter Formation of Borosilicate-Glass (BSG) Layer using UV Laser (UV Laser를 이용한 Borosilicate-Glass (BSG)층의 선택적 에미터 형성)

  • Kim, Ga Min;Chang, Hyo Sik
    • Korean Journal of Materials Research
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    • v.31 no.12
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    • pp.727-731
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    • 2021
  • In this study, we have investigated a selective emitter using a UV laser on BBr3 diffusion doping layer. The selective emitter has two regions of high and low doping concentration alternatively and this structure can remove the disadvantages of homogeneous emitter doping. The selective emitters were fabricated by using UV laser of 355 nm on the homogeneous emitters which were formed on n-type Si by BBr3 diffusion in the furnace and the heavy boron doping regions were formed on the laser regions. In the optimized laser doping process, we are able to achieve a highly concentrated emitter with a surface resistance of up to 43 Ω/□ from 105 ± 6 Ω/□ borosilicate glass (BSG) layer on Si. In order to compare the characteristics and confirm the passivation effect, the annealing is performed after Al2O3 deposition using an ALD. After the annealing, the selective emitter shows a better effect than the high concentration doped emitter and a level equivalent to that of the low concentration doped emitter.

Research on Ultraviolet Light Degradation According to Types of Encapsulants for PV Modules (태양광 모듈용 봉지재 종류에 따른 자외선 광열화 연구)

  • Seungah Ur;RakHyun Jeong;JuHwi Kim;Chanyong Lee;Lee Jaehyeong
    • Current Photovoltaic Research
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    • v.11 no.4
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    • pp.108-113
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    • 2023
  • Pressure to reduce costs in the current solar market is driving the development and implementation of new module designs and prompting the use of new materials and components. In order to utilize the variability of each material that makes up the module, it is essential to understand the basic characteristics of the material. In this article, we evaluate light degradation after UV irradiation as an encapsulation material. Measure and analyze the results of various characteristic tests for discoloration, optical and electrical property degradation before and after UV accelerated testing. To evaluate weathering stability, UV tests were performed comparing existing EVA and UVT-EVA, POE and improved low-cost POE. Even in the weather resistance test with a total UV exposure of 60 kW/m2, the properties of the encapsulants were mostly stable. EVA and POE-based encapsulants showed slight differences, and these slight differences are believed to pose a threat to long-term stability. This study is a basic analysis of encapsulation research for PV modules and will be helpful in understanding future development and encapsulant properties.

Effect of GAC Packing Mass in Hybrid Water Treatment Process of PVdF Nanofibers Spiral Wound Microfiltration and Granular Activated Carbon (PVdF 나노섬유 나권형 정밀여과와 입상 활성탄의 혼성 수처리에서 활성탄 충진량의 영향)

  • Kyung, Kyu Myung;Park, Jin Yong
    • Membrane Journal
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    • v.27 no.1
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    • pp.68-76
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    • 2017
  • Flat membrane with $0.4{\mu}m$ pore size was prepared with PVdF (polyvinylidene fluoride) nanofiber, which has the advantages such as excellent strength, chemical resistance, non-toxicity, and incombustibility. The spiral wound module was manufactured with the flat membrane and a woven paper. Hybrid water treatment process was composed of the PVdF nanofibers spiral wound microfiltration and granular activated carbon (GAC) adsorption column. Effect of GAC packing mass was investigated by comparing the case of recycling or discharging the treated water using the synthetic solution of kaolin and humic acid. After each filtration experiment, water back-washing was performed, and recovery rate and filtration resistances were calculated. Also, effect of GAC adsorption was compared by measuring turbidity and $UV_{254}$ absorbance. As a result, there was no effect of GAC packing mass on turbidity treatment rate; however, the treatment rate of $UV_{254}$ absorbance was 0.7~3.6% for recycling the treated water, and increased to 3.2-5.7% for discharging the treated water. In the case of recycling the treated water, reversible filtration resistance ($R_r$) and irreversible filtration resistance ($R_{ir}$) trended to decrease as increasing GAC packing mass; however, total fitration resistance ($R_t$) was almost constant, and recovery rate of water back-washing trended to increase a little.

Protective Effect of Nitric Oxide against Oxidative Stress under UV-B Radiation in Maize Leaves (UV-B 조사시 옥수수 잎의 산화적 스트레스에 대한 Nitric Oxide의 보호효과)

  • Kim, Tae-Yun;Jo, Myung-Hwan;Hong, Jung-Hee
    • Journal of Environmental Science International
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    • v.19 no.12
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    • pp.1323-1334
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    • 2010
  • The effect of nitric oxide (NO) on antioxidant system and protective mechanism against oxidative stress under UV-B radiation was investigated in leaves of maize (Zea mays L.) seedlings during 3 days growth period. UV-B irradiation caused a decrease of leaf biomass including leaf length, width and weight during growth. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated UV-B stress induced growth suppression. NO donor permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under UV-B stress, suggesting that NO has protective effect on chloroplast membrane in maize leaves. Flavonoids and anthocyanin, UV-B absorbing compounds, were significantly accumulated in the maize leaves upon UV-B exposure. Moreover, the increase of these compounds was intensified in the NO treated seedlings. UV-B treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in maize leaves, while NO donor prevented UV-B induced increase in the contents of malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that NO serves as antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, catalase (CAT) and ascorbate peroxidase (APX) in maize leaves in the presence of NO donor under UV-B stress were higher than those under UV-B stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the maize leaves arrested NO donor mediated protective effect on leaf growth, photosynthetic pigment and free radical scavenging activity. However, PTIO had little effect on maize leaves under UV-B stress compared with that of UV-B stress alone. $N^{\omega}$-nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), significantly increased $H_2O_2$ and MDA accumulation and decreased antioxidant enzyme activities in maize leaves under UV-B stress. This demonstrates that NOS inhibitor LNNA has opposite effects on oxidative resistance. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative stress induced by UV-B radiation and thus confer UV-B tolerance.

The Effect of Annealing Methods on Dopant Activation and Damage Recovery of Phosphorous ion Shower Doped Poly-Si (다결정 실리콘 박막 위에 P이온 샤워 도핑 후 열처리 방법에 따르는 도펀트 활성화 및 결함 회복에 관한 효과)

  • Kim, Dong-Min;Ro, Jae-Sang;Lee, Ki-Yong
    • Journal of the Korean Electrochemical Society
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    • v.8 no.1
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    • pp.24-31
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    • 2005
  • Ion shower doping with a main ion source of $P_2H_x$ using a source gas mixture of $PH_3/H_2$ was conducted on excimer-laser-annealed (ELA) poly-Si.The crystallinity of the as-implanted samples was measured using a UV-transmittance. The measured value using UV-transmittance was found to correlate well with the one measured using Raman Spectroscopy. The sheet resistance decreases as the acceleration voltage increases from 1kV to 15kV at the moderate doping conditions. It, however, increases as the acceleration voltage increases under the severe doping conditions. The reduction in carrier concentration due to electron trapping at uncured damage after activation annealing seems to be responsible for the rise in sheet resistance. Three different annealing methods were investigated in terms of dopant-activation and damage-recovery, such as furnace annealing, excimer laser annealing, and rapid thermal annealing, respectively.

Development of Surface Improvement Technique of Japanese Larch flooring Board(I) (낙엽송 마루판재의 표면강화처리기술개발(I))

  • Park, Sang-Bum
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.3
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    • pp.31-38
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    • 1999
  • This paper deals with a coating technique of hardening surface layer of softwood{Larix leptolepis) flooring board to improve its surface properties such as hardness and abrasion resisitance without spoiling its exellent qualities such as beautiful color tones and great strength. For surface hardening of the wood, polyurethane wood sealer was used as under coat, polyurethane sanding sealer as intermediate coat, and UV-curing epoxy acrylate and urethane acrylate varnishes as top coat. The hardness of the wood was improved by the coating treatment and it was similar to that of high density hardwood such as oak, keruing. The abrasion resistance of the coated wood was greatly improved by UV curing epoxy acrylate or urethane acrylate varnishes. Adhesion properties and impact resisitance of the coated wood surface were also good. It was suggested that the well-coated larch wood could be used as interior flooring board as substitute for hardwood such as keruing.

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