• 한국재료학회지
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• 제32권10호
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• pp.442-447
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• 2022

Sealing treatment is a post-surface treatment of the plasma spray coating process to improve the corrosion resistance of the coating material. In this study, the effect of the sealing on the corrosion resistance and adhesive strength of the plasma spray-coated alumina coatings was analyzed. For sealing, an epoxy resin was applied to the surface of the coated specimen using a brush. The coated specimen was subjected to a salt spray test for up to 48 hours and microstructural analysis revealed that corrosion in the coating layer/base material interface was suppressed due to the resin sealing. Measurement of the adhesive strength of the specimens subjected to the salt spray test indicated that the adhesive strength of the sealed specimens remained higher than that of the unsealed specimens. In conclusion, the resin sealing treatment for the plasma spray-coated alumina coatings is an effective method for suppressing corrosion in the coating layer/base material interface and maintaining high adhesive strength.

• 한국안전학회지
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• 제19권4호
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• pp.80-85
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• 2004

Electromagnetic interference(EMI) shielding characteristics of composite filled with Cu flake and carbon brush powder as hybrid conductive filler and EAF slag have been studied. The coaxial transmission line method of ASTM D4935-99 was used to measure the EMI Shielding effectiveness of composites as formulation in frequency rage $100\~1,000MHz$ The SE also increases with the increase in flier loading. The hybrid filler filled composites show higher SE compared to that of only Cu flake. The correlation between SE and conductivity of the various composites is also discussed. The results indicate that the composites having higher filler loading$({\geq}40wt.\%)$ can be used for the purpose of safety materials to protect hazardous electromagnetic interference.

• 반도체디스플레이기술학회지
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• 제2권4호
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• pp.27-30
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• 2003

The effect of fabrication method of catalytic layer on electrode performance has been investigated. Brush, spray gun and screen printer were used as fabrication tool and catalytic layers were formed by several methods in screen printing. Direct screen printing on polymer membrane, screen printing on carbon paper, and their combined method were applied. In the electrode fabricated by the screen printing method, Pt loading of Pt/C catalysts could be cut down to 50%, compared with results by the brushing and spraying methods. The best result of electrode was obtained as 0.6 V, at 1 A/$\textrm{cm}^2$ when catalytic layer was formed by the combined way.

• 한국연초학회지
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• 제31권1호
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• pp.18-28
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• 2009

This study describes the manufacturing method of antioxidant filter and evaluate the reduction of free radical and biological activity from mainstream smoke. When we used spray-brush for the application of antioxidant solution to the filter, cv(coefficient of variation) levels of antioxidant added to filter ranged within 3 %, which means stable and constant feeding process. 0.3~0.5mg per cigarette of antioxidant were sprayed to acetate and active carbon part in the filter plug, respectively. It was considered that the use of antioxidant added filter resulted in the reduction of the gaseous compounds of free radicals from 17 % to 19 % in the mainstream smoke. Variation for removal efficiency of free radical in antioxidant filter added to acetate part was more pronounced than that of filter added to active carbon part. Smoking deliveries of tar, nicotine for the antioxidant added filters were similar when comparing to the non-antioxidant added filter, but the delivering amounts of isoprene were significantly reduced. The estimation of consumed GSH(glutathion) showed that the gaseous toxicity of the antioxidant added filter was 14 % ~ 23 % lower than that of non-antioxidant added filter. No significant differences were observed for the total taste quality in sensory evaluation.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1855-1862
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• 2023

Graphite crucibles are used for melting uranium and its alloys in VIM furnace. Various coating materials namely Al₂O₃, ZrO₂, MgO etc. are applied on the inner surface of the crucibles using paint brush or thermal spray technique to mitigate U-C interaction. These leads to significant amount of carbon pick-up in uranium. In this study, the attempts are made to develop multilayer coatings comprising of SiC/Y₂O₃ and Mo/Y₂O₃ on graphite to study the feasibility of minimizing U-C interaction. The parameters are optimized to prepare SiC coating of about 70㎛ thickness using CVD technique on graphite coupons and subsequently Y₂O₃ coating of about 250㎛ thickness using plasma spray technique. Molybdenum and Y₂O₃ layers were deposited using plasma spray technique with 70㎛ and 250㎛ thickness, respectively. Interaction studies of the coated graphite with molten uranium at 1450℃ for 20 min revealed that Y₂O₃ coating with SiC interlayer provides physical barrier for uranium-graphite interaction, however, this led to the physical separation of coating layer. Y₂O₃ coating with Mo interlayer provided superior barrier effect showing no degradation and the coatings remained intact after interaction tests. Therefore, the Mo/Y₂O₃ coating was found to be a promising solution for minimizing carbon pick-up during uranium/uranium alloy melting.

• 공업화학
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• 제28권1호
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• pp.112-117
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• 2017

이 연구에서는 피페라지노메틸-비스-포스폰산(PIPEABP), 메틸피페라지노메틸-비스-포스폰산(MPIPEABP), N,N-디메틸렌디아미노메틸-비스-포스폰산(MDEDAP) 그리고 비스-디메틸아미노메틸 포스핀산(DMDAP)의 화학 첨가제로 처리된 중질섬유판(MDF)의 연소가스 발생을 시험하였다. 15 wt%의 인-질소산류 첨가제 수용액으로 중질섬유판에 붓으로 3회 칠하여 실온에서 건조시킨 후, 콘칼로리미터(Conecalorimeter, ISO 5660-1, 2)를 이용하여 연소가스의 발생을 시험하였다. 그 결과, 인-질소산류 첨가제로 처리한 시험편의 최대연기발생률($SPR_{peak}$)은 무처리 시험편에 비교하여 18.5~41.5%로 낮게 나타내었다. 그러나 인-질소산류 첨가제로 처리한 시험편에 대한 최대일산화탄소 생성($CO_{peak}$), (6.7~24.2)%은 공시험편보다 높게 나타났다. 또한 최대이산화탄소 발생($CO_{2peak}$), (4.2~24.4)%은 공시험편보다 낮게 나타났다. 반면에 $O_2$의 최대결핍률은 사람에게 치명적일 수 있는 수준인 15%보다 훨씬 높으므로 그로 인한 위험성은 피할 수 있었다. 결론적으로 MDF에 인-질소산류로 처리한 시험편은 부분적으로 연소성이 억제되었다. 그러나 일산화탄소의 감소에는 부정적인 영향을 미쳤다.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.307-318
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• 1988

가토 신장 피질에서 Percoll density gradient방법으로 분리한 basolateral membrane vesicle (BLMV)에서 rapid filtration technique을 이용하여 succinate의 이동 특성을 관찰하였다. $Na^+$은 succinate의 이동을 증가시켜 "overshoot"현상을 보였으며 이러한 효과는 $K^+,{\;}Li^+,{\;}Rb^+,{\;}choline$과 같은 다른 양이온들에 의해 나타나지 않았다. $Na^+$농도변화에 따른 succinate의 이동율은 sigmoid모양을 보였고, $Na^+$에 대한 Hill coefficient는 2.0이었다. soccinate의 이동은 vesicle 내부가 음전압일 때 더욱 증가되었다. BLMV에서 succinate이동은 용액내 pH변화에 따라 영향을 받았으나 brush border membrane vesicle (BBMV)에서는 영향을 받지 않았다. 동력학적 분석결과 succinate의 Km값은 $15.5{\pm}0.94{\;}{\mu}M$이었고 Vmax는 $16.22{\pm}0.25{\;}n{\;}mole/mg{\;}protein/min$이었다. succinate의 이동은 $4{\sim}5$탄소를 가진 dicarboxylate들에 의해 강력하게 억제되었으나 monocarboxylate나 다른 유기음이온들에 의해 영향을 적게 받거나 받지 않았다. succinate의 이동은 DIDS, SITS, furosemide와 같은 음이온 이동 억제제와 harmaline과 같은 $Na^+$ 이동 억제제에 의해 억제되었다. 이들 결과들은 BLMV에서 succinate는 $Na^+$에 의존하여 이동하며 다른 Krebs cycle중간 산물들과 동일한 운반기전을 이용함을 가르킨다. 또한 BLMV에서 succinate의 이동은 그 기질특이성에 있어서 다른 연구자에 의해 보고된 BBMV에서 이동특성과 유사함을 보였다.

• 한국화재소방학회논문지
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• 제33권4호
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• pp.16-27
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• 2019

실리콘 화합물인 Sodium silicate, 3-aminopropyltrimethoxysilane 졸, 3-(2-aminoethylamino) propylmethyl-dimethoxysilane 졸, 3-(2-aminoethylamino) propyltrimethoxysilane 졸로 표면 처리한 편백목재 시편의 연기 및 연소가스 발생에 대한 시험을 하였다. 실리콘 화합물 졸로 각각 편백목재 시험편에 붓으로 3회 칠하였다. 콘칼로리미터(ISO 5660-1)를 사용하여 연기 및 연소가스를 분석하였고 연기는 새로운 연기위험성 평가 방법을 적용하여 평가하였다. 실리콘 화합물로 처리한 목재시험편의 연기성능지수(SPI)는 편백목재보다 1.66~8.42배 증가하였고, 연기성장지수(SGI)는 11.8~88.2% 감소하였다. 연기강도(SI)는 편백목재보다 1.0~50.5% 감소되었고, 연기 및 화재 위험성이 낮아짐을 예측할 수 있었다. 실리콘화합물로 처리한 시험편의 세 번째 최대일산화탄소(CO_peak)농도는 공시편보다 22.5~33.3% 감소되었다. 그러나 미국직업안전위생관리국(OSHA) 허용기준(PEL)인 50 ppm보다 1.48~1.72배 높은 치명적인 독성을 발생시키는 것으로 측정되었다. 편백목재 자체는 일산화탄소 생성 농도가 높았지만 실리콘 화합물은 일산화탄소를 감소시키는 역할을 하였다.

• 대한치과보철학회지
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• 제41권3호
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• pp.319-324
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• 2003

Statement of problem. Adhesives in dentistry playa major role in the success of restorative treatments. In the treatment of all ceramic restoration it is needed to find the adequate bond strength between enamel and dentin. Purpose. The purpose of this study was to evaluate shear bond strength of resin cement bonded to extracted human uncut enamel, cut enamel, and dentin in vitro. Material and methods. Ten freshly extracted anterior teeth without any previous restorative treatments were chosen. The extracted teeth were embedded in PMMA cold acrylic in the shape of a cylinder, 25 mm in diameter by 25 mm in height. The bonding system used was as follow: Uni-Etch (32% phosphoric acid), One-Step adhesive, Duolink resin cement. The specimens were acid etched and rinsed with water. Two layers of One-Step adhesive were coated with a disposable brush on the uncut enamel. VIP curing light at $500mV/cm^2$ was used to cure the adhesive. For cut enamel shear bond test, the specimen used for uncut enamel was further reduced approximately $0.3{\sim}0.5mm$ using a laminate preparation diamond bur (0.3 mm in depth). The specimens were subsequently treated with 320-grit SiC paper followed by 600-grit SiC paper and cleaned with distilled water. The bonding procedure on the cut enamel was same as uncut enamel bonding procedure. For dentin bonding test, the specimen used for cut enamel was further reduced approximately $0.5mm{\sim}1.0mm$ using a laminate preparation diamond bur (0.5 mm in depth of diamond cutting). The amount of reduction was evaluated with the silicone mold. The specimens were subsequently treated with 320-grit SiC paper followed by 600-grit silicon carbon paper and cleaned in distilled water. The bonding procedure on the dentin was same as uncut enamel bonding procedure. All samples were mounted and secured on the Ultradent shear bond test sample holder, and Ultradent restricted shear bond testing device was used with Universal Instron machine until fracture. Analysis of variance (ANOVA) test was performed comparing the result at P<0.05. Multiple comparison (Tukey) was used to compare each groups. Result. The result showed that the mean value in shear bond strength of resin cement bonded to uncut enamel, cut enamel and dentin were 27.04 Mpa, 30.25 Mpa and 26.39 Mpa with respect. Conclusion. Within the limitation of this study, the mean value of the shear bond strength of cut enamel was higher than those of uncut enamel or dentin. However there existed no statistical differences between three different human dentition substrates due to increased adhesive characteristics.

• 한국입자에어로졸학회지
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• 제18권1호
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• pp.9-21
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• 2022

In this study, a novel antiviral coating method for the air filtration system of subway station was investigated. Using dry aerosol coating process, we developed a high-performance antiviral air filter with spark discharger and carbon brush type ionizer. Silver nanoparticles were produced by a spark discharge generation system with ion injection system and were used as antiviral agents coated onto a medium grade air filter. The pressure drop, filtration efficiency, and antiviral ability of the filter against aerosolized MS2 virus particles as a surrogate of SARS-CoV-2 virus were tested with dust contamination. Dust contamination caused the increase of the filtration efficiency and pressure drop, while the antiviral agents (in this study, silver nanoparticles) coating did not have any significant effect on the filtration efficiency and pressure drop. Using these properties, we suggested a novel method to maximize the antiviral performance of the antiviral air filter that was contaminated by dust particles. Moreover theoretical analysis of antiviral ability with dust contamination and re-coated antiviral agents was carried out using a mathematical model to calculate the time-dependent antiviral effect of the filter under actual conditions of subway station. Our model can be used to apply on antiviral air filtration system of subway station for prevention of pandemic diffusion, and predict the life cycle of an antiviral filter.