• Composites Research
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• v.33 no.2
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• pp.44-49
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• 2020

The cure kinetics of carbon fiber-reinforced prepreg for Vacuum Bag Only(VBO) process was studied by differential scanning calorimetry (DSC). The total heat of reaction (ΔH_total = 537.1 J/g) was defined by the dynamic scanning test using prepregs and isothermal scanning tests were performed at 130℃~180℃. The test results of isothermal scanning were observed that the heat of reaction was increased as the temperature elevated. The Kratz model was applied to analyze the cure kinetics of resin based on the test results. To verify the simulation model, the degree of cure from panels using different cure cycles were compared with the measurement. The simulation model showed that the error against the experimental value was less than 3.4%.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.207-207
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• 2011

본 논문은 공장 등에서 버려지는 중온온도영역($100{\sim}250^{\circ}C$)에서의 패열을 잠열축열 시스템에서 유용하게 사용을 목적으로 잠열축열재인 에리스리톨와 만니톨 그리고 이것들을 혼합한 혼합물에 대한 조사에 관한 것이다. 또한, 만니톨에 에리스리톨을 첨가하는 것에 의해 융해 응고온도가 조정의 가능성에 대해서도 조사한다. 이때 에리스리톨과 만니톨 그리고 이것들의 혼합물의 융점과 잠열량은 시차주사열량계(DSC)를 이용하여 측정되며, 시험관안에 상변화물질을 충전하여 융해 응고거동을 디지털 카메라를 이용하여 관찰 된다. DSC측정결과에서는 만니톨의 함유량이 50~60mass%에서는 3개의 융점, 70~90mass%에서는 2개의 융점을 나타내는 것을 확인할 수 있었다. 또한 시험관을 이용한 실험결과에서는 만니톨의 함유량에 따라서 각 각 다른 융해 응고거동이 일어나는 것을 확인할 수 있었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.73-79
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• 2003

This paper describes the characteristics of capacitor elements at self healing. Self healing events were forced to be created by the over-rated voltage of the capacitor elements. The self healing site was photographed by the Scanning Electron Microscope and the by-products of self healing were analyzed by the Energy Dispersive X-ray Spectrometer. Also the self healing site was analyzed by the Differential Scanning Calorimeter and the Fourier Transform Infrared Spectrometer. As a result, the main component of by-products due to the hum cut at self healing was carbon. The Fourier Transform Infrared analysis result of the self-healing specimen was similar to that of the virgin specimen, however, different from that of the specimen thermally treated at 500$^{\circ}C$. It was observed that heat flow peaks of virgin specimen were different from self-healing specimen by the Differential Scanning Calorimeter analysis.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.120-123
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• 2000

최근 첨단 과학기술의 급속한 발전에 따라 각종 화학물질이 여러분야에서 제조되고 또한 취급되고 있다. 이들 화학물질은 그 합성, 정제 및 사용법 등에 대해서는 각종 문헌에 잘 기재되어 있으나 그 위험성에 대해서는 충분히 파악되어 있지 않았거나 발표되어 있지 않은 것이 많아 대상이 되는 반응조건 이나 제조조건을 변경해야하는 경우 제조자 스스로 결정해야 하는 경우가 많아 뜻하지 않은 재해가 발생하는 예가 증가하고 있다. 따라서 본 연구에서는 의약품 및 농약 등 합성시 중간체로서 널리 사용되고 있으나 구조적인 특성상 열에 매우 불안정하여 산안법상 위험물중 폭발성물질로 분류되어 있는 니트로페닐하이드라진에 대한 열분해 특성을 시차주사열량계(DSC) 및 가속 속도열량계(ARC) 이용하여 그 위험성을 평가하였다. (중략)

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.23-28
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• 1997

The phase diagram for the surfactant mixture system of N-dodecanocyl-N-methyl amido polyolcarboxyl alkyl ether(DGC)/N-dodecanocyl-N-alkyl glucamine(DG)/water was studied usingpolarized microscopy, differential scanning calorimetry(DSC) and rheological measurements respectively. Using polarized microscopy, the textures of liquid crystal phases obtained at various surfactantconcentrations were investigated as a function of surfactant concentration and temperature, and phasetransitions between anisotropic liquid crystal phases and isotropic liquid phase were examined usingDSC measurements. Viscoelastic properties of surfactant solutions determined between hexagonal andlamellar liquid crystal phase by rheological measurements were approximately consistent with the resultsobtained by polarized microscopy and DSC. In the study for the phase of DGC/DG(5:5 mol ratio)/water system. It could be found that the hexagonal liquid crystal phase appeared at 25${\sim}$60wt％ ofsurfactant, the cubic liquid crystal phase at 50${\sim}$65wt％ and the lamellar crystal phase at above 70wt％.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.34-39
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• 2016

Arrhenius kinetic constants, the activation energy and the pre-exponential factor, of energetic material $BKNO_3$ are estimated using Differential Scanning Calorimetry (DSC). Different from the conventional way, the activation energy was estimated more precisely through DSC aging trial, and the consumed fraction by heat was calculated by comparing the integration of heat flow. We suggested the condition of accelerated aging test for the energetic material $BKNO_3$ and reconsidered the meaning of the thermal accelerated aging.

• Composites Research
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• v.24 no.4
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• pp.5-10
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• 2011

As environmental pollution getting worse, biodegradable materials have been drawn more attention than ever. In this study, polylactic acid (PLA)/carbon nanotubc (CNT) nanocomposites were manufactured via extrusion molding and injection molding, In order to change the crystallinity, annealing treatment was done for different time span, Crystallization kinetics of PLA was analyzed by differential scanning calorimeter (DSC), and it was confirmed that a proper amount of CNT can increase the crystallization rate of PLA. In addition, the presence of CNT significantly accelerates the hydrolytic degradation rate of PLA, however, it decreases with the increase of crystallinity. The reason is that degradation may occur in the PLA/CNT interface easily, and the molecular structure of the composite becomes dense with the increase of crystallinity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.257-263
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• 2008

We have examined explosion characteristics of bituminous coal dusts in cement manufacturing process. In order to find the thermal properties, we investigated weight loss and ignition temperature of coal materials using TGA and DSC. Also specific surface area of dust was investigated. Dust explosion experiments with Hartman's dust explosion apparatus have been conducted by varying concentration and size of coal dust for explosion probability and lower limit explosion concentration. According to the results for thermal properties, there is a little change by dust size. However, the specific surface area of dust is increased by decreasing dust size. The explosion test results show that small size and increasing concentration of dusts make dust explosion easier. And we find that the lower limit explosion concentration of bituminous coal is $0.3mg/cm^3$ and the probability is 100% on $0.9mg/cm^3$ in 170/200 mesh used in cement manufacturing process.

• Korean Journal of Materials Research
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• v.5 no.4
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• pp.405-411
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• 1995

급냉응고된 Al-3.51wt%Li-0.34wt%Zr 합금의 시효거동을 시차주사열량계(DSC)에 의한 열분석 방법으로 조사하였다. DSC에 의한 비열측정 결과 $\delta$’의 석출에 의한 발열반응과 $\delta$, $\beta$ 및 복합석출상의 석출에 의한 발열반응을 확인하였으며 $\delta$’ 및 $\delta$의 재고용에 의한 2개의 흡열반응을 확인하였다. 7$0^{\circ}C$ 저온시효시 $\delta$’의 석출에 의한 발열반응 이전에 흡열반응이 나타났으며 이것은 $\delta$’ 석출 이전에 $\delta$’ 전구생성물이 형성되었음을 의미한다. DSC 곡선상에 나타난 발열과 흡열곡선을 해석하여 얻은 $\delta$’상 석출과 재고용의 활성화에너지값은 각각 83KJ/mol과 98KJ/mol로서 Al-Li 2원계 및 Al-Li-Mg에 비해 높은 값을 나타내엇으며, 시효에 의한 강화가 일어나 DSC에 의한 비열변화 조사결과 나타난 $\delta$’상 석출 완료 시효조건점 (21$0^{\circ}C$, 1시간)에서 최고경도값(Hv 160)을 나타내었다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.976-981
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• 2012

In this study, hardness, microstructure and temperature of glass transition are measured respectively by using SEM (Scanning electron microscope) and DSC (Differential scanning calorimeter) to analyze the effects on material properties by after-curing in the epoxy resin. As the result of hardness test according to the after-curing conditions, the higher the temperature of after-curing, hardness and heat resistance are, the higher hardness is. As a result of microstructure for each specimen by SEM, it could be confirmed that the specimen with after-curing has more dense fracture surface. It is also found that temperatures of glass transitions by DSC are comparatively higher in the specimens with after-curing, and the differences between after-curing conditions are negligible.