• School Science Journal
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• v.12 no.2
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• pp.218-225
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• 2018

우리나라 화학 교육과정에서 표면장력은 분자 간 상호작용과 함께 지속적으로 제시되어 온 개념이지만, 지금까지 다뤄진 표면장력은 과학적 정의보다는 단순히 현상이나 사례의 측면으로만 제시되는 경향이 있다. 따라서 본 연구에서는 표면장력에 대한 새로운 교수학습 방법을 마련하고자 과학적 정의에 기반을 둔 표면장력 측정 실험 장치를 개발하고자 하였다. 선행 연구에서 제시한 표면장력 측정 장치들의 한계점을 분석하였고, 실험의 직관성, 편리성, 정확성 등에 초점을 맞추어 Wilhelmy 평판법(Wilhelmy plate method) 기반의 표면장력 측정 장치를 개발하였다. 6종 액체의 표면장력을 측정함으로써 제작된 표면장력 측정 장치가 짧은 시간 내에 정확하고 정밀한 값을 측정할 수 있다는 것을 확인하였다. 본 연구에서 제안하는 표면장력 측정 장치는 추후 화학 수업 현장에서 표면장력 교수와 측정을 위해 사용될 수 있다.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.100-108
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• 2004

Nitramine-polymer composites suffer from a problem known as dewetting. Dewetting adversely affects the performance and the sensitivity characteristics of an explosive composition. Voids, which are generated between explosive particles and binder on dewetting, act as initiation sites. For a PBXs as well as propellants, where good adhesion and mechanical properties are of great importance, dewetting therefore must be prevented by strong adhesion between the filler and the binder. The surface energy of materials is measured by Wilhelmy plate and wicking method. The interfacial energy between the filler and the binder is calculated from the disperse phase and the polar phase of surface energy. Time dependent compressive properties of composite explosives have been determined by stress-strain curves obtained at different strain rates and temperatures. The interfacial state of the PBX was observed through SEM. It was found from the result that the interface between the explosive and the binder becomes better adhesion with decreasing interfacial tension and increasing work of adhesion. The result clearly shows that the castable PBX has good adhesion more than the pressable PBX.

• Journal of the Korean Applied Science and Technology
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• v.17 no.4
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• pp.213-225
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• 2000

Sophorolipids were biosynthesized using a strain of yeast, Torulopsis bombicola ATCC22214. It has been reported that this yeast gives the highest yields for the production of biosurfactant sophorolipids. Hence, this yeast was used in this study. One of the objectives of this study is to increase the yield of the sophorolipid synthesis. To meet this end, basic culture medium was formulated on the basis of literature research to-date. When this medium was used, the increase in yield from 15% to 150% was observed compared to using the media in the literature. To examine how the interfacial characteristics of sophorolipids change with substrate, glucose (the first carbon source) was maintained in the media and after being cultured for three days, the second carbon sources such as alkanes, vegetable oils, alcohols or organic acids were added. The whole broth was extracted twice with ethyl acetate and the extract was analyzed by thin layer chromatograhy(TLC). After qualitative analyses by TLC, surface tensions of sophorolipids were measured by the Wilhelmy plate method and critical micelle concentration(CMC) was determined using these surface tension data. Also, interfacial tensions were measured by the spinning drop method and emulsions of the three-component water/decane/sophorolipid system were tested. Sophorolipids were effective and efficient in terms of surface tension reduction and CMC, but they were ineffective as emulsifiers because emulsions were separated within 30 minutes.