• 접착 및 계면
• /
• 제20권4호
• /
• pp.140-145
• /
• 2019

환경적 관점에서 고분자필름이나 코팅제 산업계에서 이산화탄소와 휘발성 유기화합물의 저감은 가장 중요한 이슈 중의 하나이다. 광경화 시스템은 용제를 사용치 않아 휘발성 유기화합물의 방출을 최소화 할 수 있고 빠른 경화로 인한 에너지 소모가 적은 잇점이 있다. 또한, 생분해성 고분자는 거대한 폐플라스틱의 발생을 고려하면 환경적으로 경제적으로 많은 관심을 받고 있다. 따라서 본 연구에서는 생분해성 고분자인 폴리락타이드 다이올과 폴리에틸렌 글리콜을 폴리올로하여 광경화형 폴리우레탄 아크릴레이트를 합성하였고 자외선에 의해 말단의 아크릴레이트 그룹의 경화반응을 진행하였다. 경화된 필름의 인장강도, 파단율 및 Tg는 폴리락타이드 다이올의 함량 증가와 더불어 증가하였고 친수특성과 열정안정성은 폴리에틸렌 글리콜 함량과 비례하였다. 따라서 친환경적인 폴리올의 함량 조절로 광경화 폴리우레탄 아크릴레이트의 물성이 조절 가능하였다.

• 한국지반신소재학회논문집
• /
• 제16권2호
• /
• pp.131-138
• /
• 2017

본 연구에서는 지반함몰을 유발하는 지반 내 공동 긴급복구 재료에 대한 팽창 및 일축압축강도 실험을 수행하였으며, 실험결과를 바탕으로 주제-경화제 구성비와 주제 내 발포제-촉진제 배합비에 따른 팽창 및 강도특성을 분석하였다. 먼저, 경화시간-팽창률 관계를 분석한 결과, 주제에 포함된 발포제와 촉진제 배합조건에 상관없이, 경화제의 비율이 높으면, 경화시간을 단축하면서 팽창률을 감소시키는 것으로 평가되었다. 이는 주제-경화제 구성비가 팽창률에 큰 영향을 미치는 것을 의미한다. 팽창재료의 강도특성을 분석한 결과, 발포제와 촉진제 배합비가 팽창재료 강도에 큰 영향을 미치는 것으로 확인되었다. 따라서 긴급복구가 요구되는 경우, 공동의 크기 및 형태 등에 따라 팽창재료의 소요 주입시간, 팽창률 및 요구강도를 고려한 주제-경화제 구성비, 주제 내 발포제-촉진제 배합비의 적용이 필요함을 확인하였다.

• Transactions on Electrical and Electronic Materials
• /
• 제16권2호
• /
• pp.82-85
• /
• 2015

Mechanical and electrical properties of epoxy/silica microcomposites were investigated. The cycloaliphatic- type epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and the curing agent was of an anhydride type. To measure the glass transition temperature (Tg), dynamic differential scanning calorimetry (DSC) analysis was carried out, and tensile and flexural tests were performed using a universal testing machine (UTM). Electrical breakdown strength, the most important property for electrical insulation materials, and insulation breakdown strength were also tested. The microcomposite with 60 wt% microsilica showed maximum values in mechanical and electrical properties.

• Journal of Information Display
• /
• 제11권2호
• /
• pp.49-51
• /
• 2010

Nanoimprint lithography (NIL) using ultraviolet (UV) rays is a technique in which unconventional lithographic patterns are formed on a substrate by curing a suitable liquid resist in contact with a transparent patterned mold, then releasing the freshly patterned material. Here, various solutions are introduced to achieve sufficient overlay accuracy and to overcome the technical challenges in resist patterning via UV imprinting. Moreover, resist patterning of all the layers in TFT and of the BM layer in CF was carried out using UV imprinting lithography to come up with a 12.1-inch TFT-LCD panel with a resolution of $1280{\times}800$ lines (125 ppi).

• 한국건설순환자원학회논문집
• /
• 제6권4호
• /
• pp.119-126
• /
• 2012

포틀랜드 시멘트는 전 세계적으로 매년 15억 톤을 생산하고 있으며, 이로 인해 전체의 배출량에 7% 이상의 $CO_2$ 가스 배출로 많은 지구환경을 지속적으로 오염을 시키고 있다. 그리고 화력발전소에서 발생하는 산업부산물인 플라이애시를 시멘트와 일부 대체하여 콘크리트에 재활용하고 있으나, 50% 이상을 해안 및 육상에 매립함으로써 환경적인 문제를 유발하고 있다. 한편 최근 결합재로 시멘트를 사용하지 않은 알칼리 활성 콘크리트에 대한 연구가 활발히 진행되고 있다. 이 알칼리 활성 콘크리트는 시멘트 대신에 실리콘(Si)과 알루미늄(Al)이 풍부한 플라이애시를 사용하여 알칼리 용액으로 활성화시킨 시멘트 ZERO 콘크리트로서 $CO_2$ 가스를 저감하는데 효과적이다. 본 연구에서는 시멘트를 전혀 사용하지 않고 결합재로서 플라이애시를 100% 사용한 지오폴리머 콘크리트를 개발할 목적으로 알칼리 활성화제와 양생조건 등이 모르타르의 압축강도에 미치는 영향에 대해 검토하였다. 그 결과, 9M NaOH과 쇼듐실리케이트를 1:1의 비율로 제조한 알칼리 활성화제를 사용하고, $60^{\circ}C$에서 48시간 동안 양생을 한 다음 기건양생을 실시할 경우 재령 28일에서 압축강도 70 MPa의 지오폴리머 모르타르를 제조할 수 있는 것으로 나타났다.

• Transactions on Electrical and Electronic Materials
• /
• 제17권3호
• /
• pp.155-158
• /
• 2016

The effect of microsilica content modified with silicone-modified epoxy on electrical and mechanical properties of cycloaliphatic epoxy/microsilica system was investigated. The cycloaliphatic epoxy resin was diglycidyl 1,2-cyclohexanedicarboxylate and curing agent was an anhydride. Surface of microsilica was modified with silicone-modified epoxy. Electrical breakdown strength, the most important property for electrical insulation materials was tested. Tensile and flexural tests were also performed using universal testing machine (UTM). The microcomposite with 60 wt% microsilica shows maximum values in electrical breakdown strength.

• 기술사
• /
• 제19권2호
• /
• pp.34-42
• /
• 1986

These brief studies and reports of the use of exposed aggrigate precast concrete in practice are combined with a description of some notable co-ordination such as shop drawing, manufacturing and erection in the field construction. Above mentioned exposed aggrigate P. C. means architectural P. C. which was used to the VOTRAKON site in Riyadh, Saudi Arabia. Fabricated P. C. on the site without autoclaving and steam curing plant had been successfully carried out on this project-core building, conference room and others. The project designed by HOPE/VTN international INC. which is located in San Diego, California U.S.A. stands for vocational training and related support facilities contract. We had to submit shop drawings showing complete information for fabrication and installation of P. C. unit reinforcement. Also we should be indicated member dimension and cross section, location size and type of necessary for erection. We can delineate the following characteristic results. One of the most important things how to handle exposed aggrigate P.C. unit as specified was quality assurance and co-ordination for shop drawing, manufacturing and erection.

• International Journal of Railway
• /
• 제6권3호
• /
• pp.90-94
• /
• 2013

Cement or lime is generally used to improve the strength of soil. However, bacteria were utilized to produce cementation of loose soils in this study. The microo rganism called Bacillus, and $CaCl_2$ was introduced into loose sand and soft silt and $CaCO_3$ in the voids of soil particles were produced, leading to cementation of soil particles. In this study, loose sand and soft silt typically encountered in Korea were bio-treated with 3 types of bacteria concentration. The cementation (or calcite precipitation) in the soil particles induced by the high concentration bacteria treatment was investigated at 7 days after curing. Based on the results of Scanning Electron Microscope (SEM) tests and EDX analyses, high concentration bacteria treatment for loose sand was observed to produce noticeable amount of $CaCO_3$, implying a significant cementation of soil particles. It was observed that higher calcium carbonate depositions were observed in poorly graded distribution as compared to well graded distribution. In addition, effectiveness of biogrouting has also been found to be feasible by bio-treatment without any cementing agent.

• 대한치과보철학회지
• /
• 제33권1호
• /
• pp.24-31
• /
• 1995

This study was performed to investigate the color stability and shear bond strength of denture repair resins. The denture base resins used in this study were Premium Super-20(Lang Dental Mfg. Co., Inc.,.U.S.A.) as heat curing resin, Triad VLC Denture Base(Dentsply/York Division, U.S.A.), Triad Reline Material(Dentsply/York Division, U.S.A.), Repair Acrylic(Lang Dental Mfg. Co., Inc.,. U.S.A.), Toughron Rebase (MikiChemical Product, Kyoto, Japan), and Tokuso Rebase(Tokuyama Soda Co., Ltd., Japan) as denture repair resin. After fabrication of specimens, they stored for 20 months, then color changes and shear bond strength were measured by colorimeter(Model TC-6FX, Tokyo Denshoku Co.) and Instron Universial Test Machine. The results were as follows : 1. There were changes of $L^{\ast},\;a^{\ast},\;b^{\ast}$ and $DE^{\ast}$ in Triad VLC Denture Base after 20 months. 2. There were changes of $a^{\ast}$ in Toughron Rebase and Tokuso Rebase, and $b^{\ast}$ in Tokuso Rebase after 20 months. 3. The shear bond strength of Repair Acrylic and Toughron Rebase were higher than that of Tokuso Rebase and Triad Reline Material.

• 한국해양공학회지
• /
• 제23권2호
• /
• pp.98-103
• /
• 2009

The resin infusion method is the latest technology of FRP laminating and cleaning to improve FRP hull quality. This method is focused on how to arrange infusion channels for the laminiating strategy. The laminating strategy using the resin infusion method has been utilized to complete the infusion work and remove the cavities on the FRP surface within the curing time. It is resulting from the arrangement of infusion and vacuum channels, the resin property, and the combination of FRP. This strategy has been depended on the field experience for manufacturing FRP without the resin infusion simulation. This study can help to improve the efficiency of FRP fabrication with the laminating strategy including the resin infusion simulation instead of the field experience.