• Journal of the Korean Ceramic Society
• /
• v.41 no.11
• /
• pp.804-811
• /
• 2004

We have studied microwave extraction process of boric acid from one of calcium borate ores, colemanite. Calcium and boron have separated by addition of sulfuric acid, and calcium has been separated out as calcium sulfate. It was possible to extract boron with the smaller amount of sulfuric acid and with short heating time in microwave heating compared to conventional heating process. The products of boric acid was the same purity and thermal characteristic, but smaller in particle size.

• Journal of Plant Biology
• /
• v.14 no.2
• /
• pp.11-14
• /
• 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.