• 공업화학
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• 제9권1호
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• pp.58-65
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• 1998

에폭시계 분체도료에 사용되고 있는 경화제로는 치환 dicyandiamide(Sub-DICY), 촉진 dicyandiamide(Acc-DICY), trimellitic anhydride(TMA), pyromellitic dianhydride(PMDA), Phenolic curing agent(Ph.C.A.)등이 사용되고 있다. 본 연구는 상기 5가지의 에폭시 경화제를 사용해서 제조한 에폭시 분체도료를 적합한 경화조건에서 완전히 경화시킨 뒤 여러 가지 실험기기 및 분석기기를 이용해서 경화된 도막 $T_g$, 인장강도, 파단신율, 경도, 내마모성등의 기계적 물성을 측정하였다. 그리고 흡수율, 내산성, 내알카리성등의 화학적물성, 전기적특성, 방식성등을 측정함으로써 경화제의 종류에 따른 에폭시 도막의 화학구조가 도막의 물성에 미치는 영향을 비교하였다. 그 결과 Phenolic curing agent는 toughness가 우수하지만 온도에 따른 색상 변화가 크고 산무수물 경화제는 전기절연성과 온도에 따른 색상안정성이 우수하지만 toughness와 부착성이 부족하고 DICY계는 흡수율과 온도에 따른 색상변화가 큰 특성을 나타내었다.

• 한국연초학회지
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• 제2권1호
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• pp.61-67
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• 1980

韓國煙草硏究所, 大邱試驗場(北緯35$^{\circ}$49')에서 1979年 透明한 fiber glass로 지은 円柱型 greenhouse(4.50$\times$3.83$\times$2.80m)內에 乾燥室의 外壁 및 天井을 Polyurethan에 함석을 입혀 黑色 paint로 coating한 板을 heat absorber겸 斷熱板으로, 乾燥室 양편에 各各 4.5㎥의 자갈을 넣은 gravel heat storage system 그리고 greenhouse內의 加熱된 空氣를 練燒室로 誘導할 수 있는 air duct를 설치한 8.25㎥의 太陽熱 直接利用 方式의 Bulk 乾燥材와 同一한 크기의 Bulk 乾燥材를 比較 試驗하였다. 乾燥期間中 外溫 30.5~35.5$^{\circ}C$, 總日射量 1004.2~1436.2 cal/$\textrm{cm}^2$의 條件下에서 3回 乾燥 試驗한 結果, 天井 heat absorber의 最高溫度는 89$^{\circ}C$이였으며, 練燒室로 吸入되는 空氣의 最高溫度는 64$^{\circ}C$이며 평균 46$^{\circ}C$로서 外溫에 비하여 18$^{\circ}C$가 높았고, 慣行Bulk乾燥材에 비하여 25%의 燃料가 節減되였다.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.393-398
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• 2001

Polymerization of light-activated restorations results in temperature increase caused by both the exothermic reaction process and the energy absorbed during irradiation. Within composite resin, temperature increases up to 2$0^{\circ}C$ or more during polymerization. But, insulation of hard tissue of tooth lowers this temperature increase in pulp. However, many clinicians are concerned about intrapulpal temperature injury. The purpose of this study was to evaluate temperature changes in the pulp according to various restorative materials and bases during curing procedure. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece fissure bur. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn below restorative materials for evaluating of temperature changes. This thermocouple was connected to temperature-recording device(Multiplication analyzer MX, 6.000, JAPAN). Temperature changes was evaluated from initial 37.$0^{\circ}C$ after temperature changes to 37.$0^{\circ}C$. Tip of curing unit was placed in the center of prepared cavity separated 1mm from restorative materials. Curing time was 40s. The restorative materials were used with Z 100, Fuji II LC, Compoglass flow and bases were used with Vitrebond, Dycal. Resrorative materials were placed in 2mm. The depth of bases were formed in 1mm and in this upper portion, resin of 2mm depth was placed. This procedure was performed 10 times. The results were as follows. 1. All the groups showed that the temperature in pulp increased as curing time increased 2. The temperature increase of glass ionomer was significantly higher than that of Resin and Compomer during curing procedure (P<0.05). 3. The temperature increase in glass ionomer base was significantly higher than that of Calcium hydroxide base during Resin curing procedure (P<0.05).

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.89-98
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• 2017

The floor heating method generally uses a wet construction method including the installation of resilient material, lightweight foam concrete, heating piping, and finishing mortar. Such a wet construction method not only delays other internal finishing processes during curing period for two mortar pouring process, but also has a disadvantage that it is difficult to replace the floor heating layer when it deteriorated because it is integrated with the frame. Dry floor heating construction method can be a good alternative in that it can solve these defects. Conversely, when it applied to the wall structure that is vulnerable to the interlayer noise compared with the column-beam structure, the question about the heavy-impact sound(HIS) insulation performance is raised. Therefore, conventional dry floor heating method is hard to apply to the wall structure apartments. Therefore, for the purpose to improve the applicability of dry floor heating method in wall structure apartments, this study investigated the change of floor impact sound, especially HIS insulation performance which is one of the required performance for the floor structure. This study tried to examine whether the change of heavy-impact sound pressure level(SPL) shows a tendency at the significant level according to the shape and mass of the floor structure. Through filed experiments on wall structure apartment, this study confirmed that the form of the raised floor shows better HIS insulation performance than the fully-supported form. In addition, it was also confirmed that the HIS insulation performance increases with the mass on the upper part. Moreover, this study found the fact that a mass of about 30 kg/m² or more should be placed on the upper structure to reduce the heavy-impact SPL according to the bang machine measuring method. Although this study has a limit due to insufficient experiment samples, if the accuracy of this study is increased, it will contribute to the diffusion of dry floor heating by setting the HIS insulation performance target and designing the dry floor heating structure that meets the target.

• 한국추진공학회지
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• 제23권4호
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• pp.92-97
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• 2019

추진제, 라이너 그리고 내열재간의 접착력을 향상시키기 위한 연구를 수행하였다. 내열재에 아무런 처리하지 않은(Bare) 상태보다는 피막처리제를 적용한 것이 접착력 향상에 유리하였다. 라이너 도포 두께가 증가할수록 내열재와 추진제간의 접착력이 향상되는 것을 확인하였으며, 라이너 경화는 24시간 경화 시간이 필요하며, 그 이상의 과경화는 접착력에 불리한 영향을 끼친다. 또한 결합제를 적용할 때가 적용하지 않을 때보다 접착력에 유리하다는 것을 알 수 있었으며, 결합제 함량이 증가할수 록 접착력도 상승하였다. 결합제 종류에 따른 접착력 변화는 HX-868이 HX-752보다 접착력이 소폭 향상되었다.

• 한국건축시공학회지
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• 제10권5호
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• pp.121-128
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• 2010

본 연구에서는 한중 콘크리트의 단열보온양생 공법재료로 사용되고 있는 이중버블시트의 다양한 포설 시공조건 변화에 따른 단열보온성능을 검토하였는데, 그 결과는 다음과 같다. 먼저, 시공요인에 따른 콘크리트의 온도이력의 경우 4시간 이내의 버블시트 포설시기 변화 및 버블시트내 함수율 변화는 전체적으로 큰 차이없이 유사한 온도이력 및 적산온도를 나타냈으나, 구조체가 얇거나 여러 장의 버블시트를 포설할 경우 시트간 간격이 크게 발생하면 콘크리트 초기양생에 불리한 요건이 발생할 수 있음을 확인할 수 있었다. 콘크리트의 코어공시체 압축강도는 버블시트의 포설시기를 지연시키거나, 시트간 간격을 크게 유발시키거나, 버블시트내 함수율을 증가시키거나, 타설 콘크리트 구조체 두께가 얇게 되는 등 콘크리트 양생에 불리한 조건을 적용시킬수록 초기 압축강도는 저하하는 것으로 나타났으나, 재령이 경과할수록 그 차이는 작아지는 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.969-972
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• 1992

It is shown that the ac breakdown strength, treeing phenomena, oxidation level, and crystallinity of unaged and aged distribution CV cables vary with XLPE insulations (characterizing anti-oxidation) and curing process. The maximum size of bow-tie tree in insulation influenced on the decrease of ac breakdown strength and the increase of oxidation level and crystallinity of XLPE according to aging time lead to increase the size and density of bow-tie trees.

• 한국염색가공학회지
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• 제4권3호
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• pp.122-130
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• 1992

To improve the physical properties and the dyeing properties of silk, the silk fabric was treated with urea resin and reactive dyeing. The effects of urea resin concentration, pH of padding bath and curing condition were investigated in order to find optimum condition and the following results are obtained The optimum condition for the crease recovery of silk fabric was urea resin concentration of 80 g/ι, pH of 7, the curings temperature of about 135$^{\circ}C$, and the curing time of 3 minutes. The crease recovery and the thermal insulation ratio of silk fabric were increased by the above treatment. K/S increased as the adding amount of Na$_2$SO$_4$ increased, K/S, however was not affected by the adding amount of Na$_2$CO$_3$. Co1or fastness of the dyed fabrics treated with urea resin were improved slightly compared with untreated ones.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.261-264
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• 2003

Cold weather can lead to many problems in mixing, placing, setting time, and curing of concrete that can have harmful effects on its properties and service life. Korean Concrete Institute (KCI) defines cold weather as a period when the average daily air temperature is less $4^{\circ}C$ and recommends to cast concrete with special care such as shielding, heating and so on. The use of high early strength cements may improve the rate of hardening characteristics of concrete in cold weather by making it possible to achieve faster setting time and evolving more hydration heat than ordinary Portland cement. Higher early strength can be achieved using Type III cement especially during the first 7 days. The strength increase property of Type III cement at low temperature was studied. As a conclusion the heat or heat insulation curing period can be reduced to 50~75%. So, it can be used for cold weather concreting to reduce construction cost and extend the construction season.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.424.1-424.1
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• 2016

태양전지 모듈의 봉지재로 사용되는 EVA(Ethylene-Vinyl acetate)는 외부의 환경으로부터 태양전지를 보호해주는 역할을 한다. 하지만 frame의 실링재나 glass edge 부분의 결함으로 인해 수분이 침투되어 모듈의 내부자재에 영향을 미치게 되며, 모듈의 효율 감소나 수명 단축의 원인이 된다. 이러한 결함을 줄이기 위해서는 EVA의 crosslinking degree, 절연 저항 특성을 향상시키는 것이 중요하다. 이에 본 연구에서는 EVA의 crosslinking degree를 보기 위해 soxhlet extraction method를 이용하여 gel content를 측정하였으며, 라미네이션 과정 중 curing time에 따른 gel content 변화를 확인하였다. 또한 이 실험을 바탕으로 gel content에 따른 절연 저항을 측정하여 EVA의 crosslinking degree에 의한 절연 저항 특성을 확인하였다.