• Horticultural Science & Technology
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• v.28 no.6
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• pp.1072-1077
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• 2010

Plant diseases including gray mold caused by Botrytis cinerea are often reduced when calcium compounds are used as alternative materials in paprika. However, much less information is available about the effects of calcium compounds on controlling of $B.$ $cinerea$. Seven calcium compounds such as calcium sulfate dihydrate, calcium chloride, calcium nitrate, calcium oxide, calcium hydroxide, calcium carbonate, and calcium hydride were evaluated for their effectiveness against $B.$ $cinerea$ on potato dextrose agar medium. The pH of selected calcium compounds was higher (pH 8.2-10) than that of the control (pH 6.6). Calcium carbonate, calcium oxide, calcium hydride, and calcium hydroxide among seven calcium compounds were more effectively inhibited the growth of $B.$ $cinerea$ than other calcium compounds. In the case of spraying the spore suspension on paprika applied with the selected four calcium compounds and supplied with the selected calcium supplements in a hydroponic culture system, the paprika treated with calcium compounds showed less severity of disease than those untreated plants. On the basis of our results, we propose that the suppressive effects of calcium compounds on $B.$ $cinerea$ in paprika resulted from the supply of calcium and a certain degree of salt stress.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.217-217
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• 1994

Calcium entry blockers, capable of inhibiting transmembrane influx of extracellular calcium through specific calcium channels, are useful drugs in the treatment of angina pectoris, hypertension, cardiac arrythmia, and various cardiovascular disorders. Compounds having isoquinoline structures have recently been reported to possess calcium antagonistic action. Therefore, in the present study, we have attempted to synthesize some isoquinoline and related compound.; in order to search for potentially effective chemicals acting on cardiovascular system, and evaluated their pharmacological properties focusing on calcium antagonistic actions. Almost all of the compounds so far synthesized, had inhibitory action against phenylephrine or high potassium-induced contraction in vascular smooth muscle with different degrees of potencies depending on their structures, However, some of tetrahydroisoquinoline analogs showed directly inhibit calcium current in isolated rabbit cardiac myocytes examined by patch clamp techniques. The pharmacological properties of these compounds need more intensive investigation as to whether these chemicals may have developed as a new cardiovascular active drugs. Therefore, we are now under investigation of the mechanism of action of these compounds.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.737-754
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• 2019

Peaches have soft tissues compared to other fruits and are vulnerable to softness, wounds, and loss of marketability due to the weak fruit hardness after harvest. It is necessary to develop a technology to improve the shelf-life of the fruit to expand the distribution of peaches. Calcium compounds and chitosan have an important role in improving the shelf-life of fruit by maintaining the hardness and reducing the respiration rate in peach fruits. In this study, to select useful compounds to improve the shelf-life of peaches, calcium citrate, calcium chloride, calcium nitrate, GH-Ca, OS-Ca, chitosan, and chitosan dissolved in calcium chloride were sprayed onto peach trees. The characteristics of the harvested fruits were investigated after the 'Kumhong' and 'Madoka' peach tree treatments. The hardness of the fruit was kept the highest with the combined treatment and remained high with the calcium citrate, chitosan and calcium nitrate treatments. Ethylene production and respiration were effectively inhibited by the GH-Ca and chitosan treatments. There was no significant difference in soluble solids content and acidity among the fruits treated with the chemicals. The coloration of the fruit skin was not delayed by the calcium and chitosan chemical treatments. Calcium compounds were increased in the fruits and leaves of the peach trees treated with the chemicals compared to the untreated ones. These results suggest that the calcium treatment extended the shelf-life by increasing the calcium content in the leaves and fruits of the peach trees.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.2
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• pp.171-176
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• 2000

The phosphatic calcium compounds such as calcium hydrogen phosphate, bone ash, hydroxyapatite and tricalcium phosphate were prepared using the high purity calcium hydroxide and calcium carbonate obtained from shell resources. Calcium hydrogen phosphate had been prepared using the high purity calcium hydroxide and phosphoric acid solution. Using the calcium hydrogen phosphate as a starting materials, bone ash have been prepared by solid state reaction method and hydroxyapatite could be obtained by hydrothermal treatment method, respectively. The tricalcium phosphate was prepared by the solid state reaction of a stoichiometic mixture of bone ash and high purity calcium carbonate. In this paper, the optimal preparation process and conditions of phosphatic calcium compounds were established.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.274-280
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• 2001

The chemical forms of calcium compounds in perilla leaves and their changes after harvest were investigated. The four types of calcium compounds extracted were as follows: water soluble calcium(F-I: mainly water soluble organic acid salts and calcium ion), IN-sodium chloride soluble calcium(F-II: calcium-pectate and calcium-carbonate), 2%-acetic acid soluble calcium(F-III: calcium-phosphate), and 5%-hydrochloric acid soluble calcium(F-IV: calcium-oxalate). The calcium content of perilla leaves was not found to vary with their age. Relatively high levels of F-l (28.4~39.5) and F-II (34.4~47.4) were found in young and mature leaves while the F-IV constituted 15.6~21.6% of the total calcium. The F-IV calcium contents of perilla. spinach and jaso were 16.8, 42.4 and 22.3%, respectively. In contrast to calcium. magnesium existed as water soluble magnesium at the highest content of 90.6% in spinach while 62.9% and 16.8% of the total magnesium existed as water soluble magnesium in perilla and jaso, repectively. The change in vitamin C and F-IV calcium content were examined for 7 days after harvest. Vitamin C content decreased slowly at the beginning but rapidly from the 4th day after harvest. On the other hand, the F-IV calcium content increased slowly at the beginning and rapidly from the 4th day of observation. This result suggests that the increase in F-IV calcium is related to the decrease in vitamin C content. This phenomena was more distinctly observed at 2$0^{\circ}C$ than 5$^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.149-159
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• 1998

To utilize the oyster shell containing a lot of calcium, we investigated the bioavailability of calcium compounds from oyster shell. First, calcium oxide was prepared by burning of oyster shell at $1200^{\circ}C$. Its purity was approximately $98.5\%$. Calcium compounds, $CaCl_2$, and $CaHPO_4$, from the calcium oxide were prepared by chemical reaction. Effect on calcium absorption by the calcium compounds from oyster shell was improved using fish skin gelatin peptides.(FSGP), which was prepared by enzymatic hydrolysis of fish skin gelatin for 4hr with tuna pyloric caeca crude enzyme (TPCCE). in vitro experiment, calcium absorption by addition of FSGP in a mixture solution of calcium and phosphate was higher approximately $70\%$ than that by control. in vivo using calcium deficient rats, a group taken the diets with $3\%$ FSGP and $CaHPO_4$ was significantly improved amount of calcium and ash in femur and strength of femur. These results suggest that calcium compounds from oyster shell and FSGP could be used as an effective dietary calcium source.

• Journal of the Korean Ceramic Society
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• v.18 no.3
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• pp.157-162
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• 1981

A converter slag has been heat-treated above melting point at reduced condition by cokes. As the result, most iron was separated. To make hydraulic compounds, calcium oxide was added to the reduced converter slag and the mixtures were sintered. This modified converter slag clinker mainly contained tricalcium silicate and calcium aluminates, and have a great potential to be a good hydraulic cement. The hydrates of the hydraulic compounds and gypsum with and without granulated slags, were mainly C-S-H, ettringite, calcium monosulfoaluminate hydrate, calcium aluminate hydrate, and $Ca(OH)_2$

• Korean Journal of Materials Research
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• v.26 no.7
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• pp.359-362
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• 2016

Mineral filler is used for resin compounds, because it increases the stiffness and thermal stability of a resin compound, and it also cuts down the cost. Calcium carbonate, silica, magnesium oxide, and others are used as filler materials in general, and the type of filler material, the size, and content can affect the physical properties of compounds. Those factors also influence the viscosity of resin mixtures and the workability, and should be adjusted by changing the contents of the filler, which depends on the size. In this study, five kinds of ground calcium carbonate, which were different in size, were used to produce polyester compounds ; the physical properties were compared with the filler size and contents. The mechanical properties were measured by bending strength and tensile strength, and the heat deflection temperature was obtained for thermal stability.

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.483-488
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• 2015

Blast furnace slag(BFS) is well known for its hardening mechanism in ordinary Portland cement with alkali activation due to its latent hydraulic property. The possibility of using calcium compound as activator for BFS has been investigated in this study. The hydration properties of calcium compound activated BFS binders were explored using heat of hydration, powder X-ray diffraction and compressive strength testing. Heat of hydration results indicate that the hydration heat of BFS is lower than OPC paste by about 50%. And ettringite as hydration product was formed continuously as the calcium sulfate was decreased. The maximum compressive strength of hardened BFS mortar at 28 days is confirmed to be 83% as compared with hardened OPC mortar.

• Elastomers and Composites
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• v.5 no.1
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• pp.69-74
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• 1970

The influence of various calcium carbonate on the physical properties of natural rubber have teen carries out extensive experiments on compounding. Final evaluation was made through various kinds of physical test-tensile strength, modulus, tear strength and hardnees-including particle size. The results are as follows: 1. Generally, tile tensile strength, modulus and tear strength showed the similar tendency in various calcium carbonate compounding. 2. The maximum volume of general using have been obtained with 150 phr calcium carbonate in $NR-CaCO_3$ compounding. 3. The particle size of domestic calcium carbonate showed $1.0\mu-2.6\mu$.