• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.231-238
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• 1986

This field experiment was undertaken to assess the effects of three levels of inclination ($10^{\circ}$, $20^{\circ}$ and $30^{\circ}$) and four rates of $N-P_2O_5-K_2O$ (0-0-0, 14-10-10, 28-25-25, and 42-40-40 kg/10a) on the hilly pasture concerning to establishment, forage yield and quality, and botanical composition in the mixed grass-clover sward set up on a new reclaimed woodland by an oversowing method. This part was concerned with the concentration and mutual balance of mineral nutrients in relation to grass tetany hazard. The results obtained were summarized as follows: 1. Concentration of exchangeable Mg, relative proportions of Mg to CEC, K, and Ca in soil were considerably below the critical level for good forage growth and prevention of grass tetany. These properties were rather worsened by increasing the inclination grade and the NPK rate. 2. Compared with the critical level for the likelihood of tetany (Mg < 0.2%, K > 2.5%, and K/(Ca+Mg) equivalent ratio > 2.2 in forages in DM basis), mean concentration of Mg in mixed forages turned out to range from 0.09 to 0.14%. 2.6% of K concentration and 2.5 of K/(Ca+Mg) equivalent ratio were shown to be at a normal NPK rate. The likelihood of grass tetany was generally enhanced by increasing the inclination grade and the NPK rate. 3. The increasing of the inclination grade and NPK rate rather aggravated the low Mg concentration and unbalanced mutual ratios of mineral nutrients, from which resulted the grass tetany hazard and the depression of forage growth. To prevent these two resulted factors, Mg fertilization on grassland and/or extra Mg supplement to dairy cattle needed to be carried out. 4. The Ca/P ratios in the mixed forages ranging from 1.0 to 2.0 were reduced by the increased rate of NPK, whereas the difference due to inclination grade was yet to be recognized.

• Reproductive and Developmental Biology
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• v.28 no.3
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• pp.167-172
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• 2004

This study was performed to examine the correlations among dog sperm viabilities evaluated by flow cytometry, by microscopic evaluation (ME), by carbo-xifluorescein diacetate and propidium iodide (CFDA/PI) and by hypoosmotic swelling (HOS) test. Semen were collected from 5 dogs ranging in age from 2 to 4 years. Each ejaculate was divided into 3 aliquots and different proportions of freeze-killed cells were added to each aliquot (1:0, 1:1 and 1:3). In the other experiment, semen was extended with Sweden extender containing 5% glycerol and equex STM paste, and frozen using liquid nitrogen vapor. Fresh and frozen-thawed dog sperm viability were assessed by flow cytometry using PI staining method. The accuracy of flow cytometry was evaluated by comparing with other classic assessments, microscopic evaluation, epifluorescence microscopic analysis using CFDA/PI, and HOS test. High correlations of sperm viabilities were found among flow cytometry, epifluorescence evaluation, HOS test (p<0.01) in fresh semen. Especially, sperm viability assessed by HOS test was highly correlated with viability by flow cytometry in all the ratios of live and dead spermatozoa, 1:0, 1:1 and 1:3 (p<0.01). The viability evaluated by ME were significantly correlated with that by flow cytometry in ratios of 1:0 and 1:3 (p<0.05) however, there was no significance in ratio of 1:1. The viability evaluated by C/p were highly correlated with that by flow cytometry in ratio of 1:0 and 1:1 (p<0.01) and significantly correlated in ratio of 1:3 (p<0.05). In frozen-thawed spermatozoa, the viability determined by HOS test was considerably correlated with that by flow cytometry (p<0.01). There was significant correlation between the viabilities by ME and by flow cytometry (p<0.05). But the viability evaluated by CFDA/PI was not correlated with viability by flow cytometry. The result from this study validate the use of flow cytometry as a precise method for assessing the viability of fresh and frozen-thawed dog spermatozoa.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.104-110
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• 2015

It is known that polymer concretes are 8~10 times more expensive than ordinary Portland cement concretes; therefore, in the production of polymer concrete products, it is very important to reduce the amount of polymer binders used because this occupies the most of the production cost of polymer concretes. In order to develop a technology for the reduction of polymer binders, smooth and spherical aggregates were prepared by the atomizing technology using the oxidation process steel slag (electric arc furnace slag, EAFS) and the reduction process steel slag (ladle furnace slag, LFS) generated by steel industries. A reduction in the amount of polymer binders used was expected because of an improvement in the workability of polymer concretes as a result of the ball-bearing effect and maximum filling effect in case the polymer concrete was prepared using the smooth and spherical atomized steel slag instead of the calcium carbonate (filler) and river sand (fine aggregate) that were generally used in polymer concretes. To investigate physical properties of the polymer concrete, specimens of the polymer concrete were prepared with various proportions of polymer binder and replacement ratios of the atomized reduction process steel slag. The results showed that the compressive strengths of the specimens increased gradually along with the higher replacement ratios of the atomized steel slag, but the flexural strength showed a different maximum strength depending on the addition ratio of polymer binders. In the hot water resistance test, the compressive strength, flexural strength, bulk density, and average pore diameter decreased; but the total pore volume and porosity increased. It was found that the polymer concrete developed in this study was able to have a 19% reduction in the amount of polymer binders compared with that of the conventional product because of the remarkable improvement in the workability of polymer concretes using the spherical atomized oxidation steel slag and atomized reduction steel slag instead of the calcium carbonate and river sand.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.29-36
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• 1985

In the previous papers (Kim and Park, 1984 a, b), we have reported on alginic acid from Ecklonia cava. The seasonal and portional variation in the composition of uronic acids and their block structures of alginic acid from Sargassum ringgoldianum (collected from Ichon-ri at the coast of Ilgwang-myon, Yangsan-gun, Kyongnam, Korea, in the period of January to December in 1982) are investigated, and their relationship between the chemical composition and some rotated properties is discussed in this study. The results are as follows: 1. One year average contents of alginic acid were $21.4\%$ in the stipe and $19.7\%$ in the frond, one-year average values of M/G ratios were 2.38 in the frond and 1.85 in the stipe. The value of frond was largest in the period of Jauuary to April and smallest in May and October to December. The value of stipe was largest January to April and smallest in May. In general, the proportions of M block in the both of frond and stipe were higher than those of G block. 2. The viscosity of frond alginic acid showed higher values of 31.1 cP in November, and lower (below 7.0 cP) in the stipe alginic acid. Furthermore, the dependence on temperature of frond alginic acid was also larger in November and others were lower. Ion exchange ability of frond alginic acid was highest in July and the exchange amounts were $Pb^{2+}\;5.2,\;Cu^{2+}\;3.1,\;Zn^{2+}\;1.7,\;Co^{2+}\;1.5$ meq/g, Na-Alg., and the ability of stipe alginic acid was highest in May and the amounts were $Pb^{2+}\;4.6,\;Cu^{2+}\;3.3,\;Zn^{2+}\;2.5,\;Co^{2+}\;1.4$ meq/g. Na-Alg.. The affinity with metallic ions appeared higher in order of $Pb^{2+}>Cu^{2+}>Zn^{2+}>Co^{2+}$, and the exchange ability assumed to relate with the block ratio of uronic acid.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.63-70
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• 2021

In order to compare and investigate the growth rates of each of the various soils, the soil mixing ratios were varied to four soils (Pitmos, Pearlite, Masato, General Soil, and Cocopeat). Ten were selected for each soil ratio and the average length and weight were compared. As a result, in the ratio of No. 1 pitmos 6.5: Perlite 2: Masato 1.5, it was measured as 16.36cm, 0.60g. In the ratio of No. 2 pitmos 10, 13.74cm, 0.41g. In the ratio of No. 3 general clay 10, it was measured as 12.43cm, 0.26g. 4 general clay 8, 0.39g. The growth rate of each soil was measured to be superior to that of other soil growth environments in the ratio of pitmos 6.5: pearlite 2: masato 1.5 soil. For ginseng plant analysis, 30 ginseng plants grown in the average length and weight of each soil at a ratio of 6.5: pearlite 2: masato 1.5 and relatively low-result general soil were selected and analyzed. As a result, 1,040ppm of nitrite nitrogen(NO₃-N) was higher in ginseng plants grown in general soil. There was no significant difference in phosphoric acid(P), potassium(K), and magnesium(Mg). Ginseng is characterized by poor growth when it exceeds 300ppm by combining ammonia tae (NH₄-N) and nitrate tae (NO₃-N) nitrogen. In addition, nitric acid produced in a part of this nitrite makes the pH reaction of the soil acidic, and the nitrite remaining in the soil evaporates into gas.