• Elastomers and Composites
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• 제54권3호
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• pp.241-246
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• 2019

Carbon master batch (CMB) rubber sheets, which are stored in stacks, are difficult to separate during reuse because of the adhesion between sheets caused by the stacked weight over time. To solve this problem, in the actual rubber product manufacturing process, various anti-tacking agents (solid powder or liquid surfactants) are applied to the sheet surface. In this study, the emulsion samples of zinc (Zn)-stearate/triethanolamine (TEA)-stearate mixtures were prepared using TEA-stearate as a surfactant, prepared using an industrially manufactured Zn-stearate powder, and their basic anti-tacking properties were studied. During the process of manufacturing emulsion, a heat treatment process and an auxiliary surfactant were introduced to improve the dispersion stability. Results showed that the heat-treated sample exhibited a significant improvement in terms of sedimentation, storage stability, and anti-tacking characteristics since the Zn-stearate particles were reduced to a smaller size by the heat-treatment than that of the original Zn-stearate powder.

• 한국대기환경학회지
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• 제13권2호
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• pp.103-113
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• 1997

The research described in this paper was conducted to estimate the stability and heat budget in planetary boundary layer (PBL) at Kimhae. The upper air observation was carried out during period from 3 Februsry 1993 to 5 February 1993 at Kimhae. The surface observation data used the one during period from 1 April 1994 to 31 March 1995. The maximum height of inversion layer observed at Kimhae was 310 m. Destruction of the inversion was simultaneously occurred at the surface and the mid-layer (200 $\sim$ 300 m), however the origin of destruction is different each other. The surface inversion is destructed by surface heating owing to growing radiation in surface but disappearance of the mid-layer inversion is related to the upper cold air movement.

• 한국식품조리과학회지
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• 제12권1호
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• pp.54-59
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• 1996

Immunoglobulins (IgY) were isolated from egg yolk of hens immunized with bovine serum albumin(BSA). The stability of anti-BSA IgY against heat and pH was investigated. Antibody activity was measured by enzyme linked immunosorbent assay. IgY was relatively heat-stable and most of the antibody activity remained after heating up 65$^{\circ}C$ for 30 minutes. IgY was stable at pH 5-11. However, inactivation of IgY was observed below pH 4, or above pH 12. Inactivation of IgY proceeded rapidly at low pHs(pH 2-3). Most of the antigen binding activity was lost at low pHs probably because of some conformational changes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.43-48
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• 2003

In this study the optimization of plate-fin type heat sink for the thermal stability is performed numerically. The optimum design variables are obtained when the temperature rise and the pressure drop are minimized simultaneously. The flow and thermal fields are predicted using the finite volume method and the optimization is carried out by using the sequential quadratic programming (SQP) method which is widely used in the constrained nonlinear optimization problem. The results show that when the temperature rise is less than 34.6 K, the optimal design variables are as follows; $B_{1}$ = 2.468 mm, $B_{2}$ = 1.365 mm, and t = 10.962 mm. The Pareto optimal solutions are also presented for the pressure drop and the temperature rise.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.789-794
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• 2008

Zinc oxide (ZnO) has been widely studied for its practical applications such as transparent conduction electrodes for flat panel displays and solar cells. Especially, ZnO films show good chemical stability against hydrogen plasma, absence of toxicity, abundance in nature, and then suitable for photovoltaic applications. However, the fabrication process of thin film solar cells require a high substrate temperature and/or post heat treatment. Therefore, the layers have to withstand high temperatures, requiring an excellent stability without degrading their electronic and optical properties. In this paper, we investigated the stability of zinc oxide (ZnO) films doped with aluminum and hydrogen. Doped ZnO films were prepared by r.f. magnetron sputter and followed by heat treatment at different temperatures and for various times.

• 구강회복응용과학지
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• 제18권2호
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• pp.93-99
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• 2002

This study was performed to investigate the color stability of IPS Empress 2 glass-ceramic after heat-pressing and/or heat-treatments. Three types of IPS Empress 2 ingots (shade 100, 300, 500) were tested. For this study, three groups were prepared as follows: group 1 is as-received material, group 2 is heat-pressed material, and group 3 is fully heat -treated material. The color of the specimens was measured with a colorimeter. The data were statistically evaluated with one-way ANOVA and Scheffe's multiple test. The results obtained were as follows: 1. IPS Empress 2 glass-ceramic demonstrated less color stability according as the shade is lighter. Namely, the shade 500 showed the lowest color shifts and the shade 100 showed the greatest color shifts after heat-pressing and heat-treatments. 2. In the cases of shade 100 and 300, the changes of ${\Delta}E^*$ were affected mostly by the changes of $L^*$ and $b^*$. 3. In ${\Delta}E^*$ of the shade 100, there were significant differences among the group 1, 2, and 3 (P<0.001). 4. In ${\Delta}E^*$ of the shade 300, there were significant differences between the group 1 and 2, and the group 1 and 3 (P<0.001). 5. In ${\Delta}E^*$ of the shade 500, there was significant difference only between the group 1 and 3 (P<0.001).

• 구강회복응용과학지
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• 제16권1호
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• pp.1-11
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• 2000

Dental temporary resin should have adequate strength and similar esthetics as natural teeth. Recently esthetics has become a high priority in clinical dentistry. Thus the evaluation of color stability of dental temporary resin has become an important part in dental research. The purpose of this study was to evaluate the difference in color stability of 3 resins($Snap^{(R)}$, Temporary bridge $resin^{(R)}$, Trim $II^{(R)}$) according to polymerizing methods and stainning. The resins were divided into groups by 2 types of polymerizing methods ( air or pressure and heat curing) The resins were dyed with coffee, chlorhexidine and artificial saliva and then the color stability was evaluated with a spectrophotometer(CM-503i, Minolta, Japan). The results were as follows ; 1. In the color stability according to polymerizing method, pressure and heat polymerizing method was higher than air polymerizing method. 2. The color stability according to staining fluid decreased in the order of I, II, III group, there was significant difference among the groups of staining fluid. 3. The color stability according to resins decreased in the order of $Snap^{(R)}$, Trim $II^{(R)}$, Temporary Bridge $resin^{(R)}$, The $Snap^{(R)}$ resin was highest color stability, there was significant difference among the 3 resins.

• 한국가금학회지
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• 제16권1호
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• pp.23-28
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• 1989

난백단백질의 농도와 당류의 첨가 수준이 난백의 열감수성에 미치는 영향을 검토하기 위하며 가열처리.($60^{\circ}C$, 5분간) 전후 난백의 기능성을 측정하였으며 그 결과는 다음과 같다. 난백단백질의 농도 8.3%까지는 가열처리 전후 난백의 탁도가 감소하였으나 희석됨에 따라 증가하다가 3.32% 이하에서는 다시 감소하였다. 가열처리 전후 난백의 기포력은 단백질 농도 8.3%에서 가장 높았으며 희석됨에 따라 점차 감소하였고 기포안정성은 단백질 농도가 희석됨에 따라 점차 저하하였다. 난백에 sucrose를 첨가할 경우 탁도의 변화가 없었으나 가열처리의 경우에는 sucrose의 첨가량에 따라 점차 감소하였다. 기포력은 sucrose 5%이상 첨가 시 감소하였으며 가열처리의 경우에는 sucrose 2.5%이상 첨가 시 점차 감소하였다. 기포안정성은 sucrose를 5%이상 진가할 경우 점차 증가하였으나 가열처리한 경우에는 sucrose의 첨가량에 따라 증가하였다. Glucose의 첨가량에 따라서는 탁도가 높아졌으며 가열처리 시에는 변화가 없었다. 기포력은 Glucose의 첨가량에 따라 점차 감소하였으며 가열처리의 경우에는 5%이상 첨가 시 다소 감소하였다. 기포안정성은 가열처리 전후 glucose의 첨가량에 따라 증가되었으며 sucrose의 첨가시 보다 크게 증가되었다.

• 한국응용곤충학회지
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• 제48권1호
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• pp.109-115
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• 2009

무당거미와 나무껍질게거미줄의 열 안정성 및 기계적 성질 등을 측정하고, 그 성질들을 합성 섬유인 아라미드(aramide)와 폴리에스테르(polyester) 등의 측정 결과와 서로 비교하였다. 열 안정성에서 거미줄은 비록 상업용 섬유로 사용되는 아라미드나 폴리에스테르에 비해서는 낮았지만 기계적인 성질에서는 폴리에스테르보다 월등 우수한 결과 값을 보여주었다. 거미줄에 포함되어 있는 수분이 열 안정성과 기계적 성질에 미치는 영향을 조사하기 위해 두 종류의 거미줄을 $100^{\circ}C$의 진공에서 각각 다른 시간 별로 열처리를 하였는데, 1.5시간 동안 열처리를 시킨 후의 열 안정성과 기계적 성질이 최고 값을 나타내었다.

• Nuclear Engineering and Technology
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• 제27권3호
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• pp.358-373
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• 1995

중수로용 개량핵 연료집합체인 CANFLEX 핵연료다발의 CANDU-6 원자로 장전시 열수송계통에 대한 유동안정성이 분석되었다. CANFLEX 핵연료다발은 기존의 37개봉 핵연료다발과 원자로출력 및 압력강하 측면에서 거의 일치되며, 이로인해 수력적 거동이 양립하는 반면, CANFLEX핵연료다발은 기존의 37개봉 핵연료다발 보다 임계채널 출력이 증가하며, 반경방향 출력분포의 평탄화로 인해 균일한 엔탈피 분포를 확보할 수 있게 된다. CANFLEX 핵연료다발 및 출구모관들의 상호연결관에 대한 SOPHT 모델을 개발하였으며, 이 모델을 이용하여 CANFLEX 핵연료다발이 장전된 월성 1호기의 유동 안정성 거동이 해석되었다. 해석결과, 열수송계통의 출구모관들의 상호연결관이 없을 경우에는 기존의 37개봉 핵연료다발과 같이 유동이 불안정함을 보였으며, 출구모관들의 상호연결관이 있을 경우에는 정격출력의 $\pm$1% 내에서 안정함을 보였다. 따라서 CANFLEX 핵연료다발의 월성 1호기 장전시 열수송계통의 유동안정성 측면에서는 건전할 것으로 판단되었다.