• 한국세라믹학회지
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• 제41권11호
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• pp.804-811
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• 2004

본 연구는 colemanite원광을 출발원료로 하여 붕산을 추출하는 공정에서 마이크로파 적용에 대한 연구로, 황산을 첨가하고 가열하여 colemanite의 칼슘 성분을 황산칼슘으로 분리하여 내고, 액상에 존재하는 붕소 성분은 붕산으로 재결정화 하여 제조하였다 Colemanite에 황산을 첨가해 가열하는 공정에 마이크로파를 적용하면, 일반 가열원을 사용하였을 때와 비교하여 적은 양의 황산을 사용하여 추출이 가능하고, 가열시간을 단축하는 것이 가능하였다. 생성된 붕산의 순도는 일반 가열원을 사용하였을 때와 동등한 수준이고 열 특성 또한 동일하였으나, 입자의 크기는 작아졌다.

• Journal of Plant Biology
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• 제14권2호
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• pp.11-14
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• 1971

Zephyranthes candida, Narcissus pseudonarcissus and Crinum asiaticum pollen were placed near their pistil parts respectively on agar cultural media(microslides) containing 10% sucrose and 100mg/l botic acid plus 1% agar with or without calcium and some other calciumsupporting inorganic salts. If fresh pistils (100% moisture) were used pollen grew toward their pistil parts, showing "positive" tropism. This was also true when combinations among three different species were made. Pollen tubes grew away from the pistils if they were dried (below 10% moisture), showing "negative" tropism. Pollen could not show any tropic growth and thus grew at random of all directions if the pistil parts were incompletely dried (approximately 50% moisture). The similar tropic responses of pollen-tube growth with the three species could be demonstrated with etiehr wet or dried tooth-pick segments. Calcium jons in the basic medium merely promated pollen-tube growth and so either "positive" or "negative" tropism became rather distinctive, but they were not tropically active. Pollen tubes grow toward pistil parts with more moisture content and seem to be hydrotropically sensitive. This was assumed due to the cohesive force existing in water molecules.esive force existing in water molecules.