• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.270-275
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• 2005

Dust cores (compressed powder cores) of $Fe-6.0wt\%Si$ alloy with a size of $35\~180\;{\mu}m$ in diameter have been prepared by phosphate coatings and annealings at $600\~900^{\circ}C$ for 1 h in nitrogen atmosphere. Further the magnetic and mechanical properties of the powder cores were investigated. As a general trends, the compressive strength and core loss decreased with the increase in annealing temperature. When annealed at $800^{\circ}C$, the compressive strength was 15 kgf, the permeability and quality factor were 74 and 26, respectively. Moreover the core loss at 50 kHz and 0.1 T induction was $750\;mW/cm^3$, and the percent permeability under the static field of 50 Oe was estimated to be about 78. In addition, the cut-off frequency in the cure representing the frequency dependence of effective permeability was measured to be around 200 kHz. These properties of the $Fe-6.0wt\%Si$ alloy dust cores could be considered to be due to the good insulation effect of iron-phosphate coats, the decrease in magnetocrystalline anisotropy and saturation magnetostriction and the increase in electric resistivity.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.107-111
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• 1990

Ginseng root explants and calli were cultured on modified Murashine and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical compositon and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of ginseng calli, the concentrations of 2, 4-D and sucrose were in the range of 1 to 5 mg/l and 1 to 3%, respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magnesium, plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.57-63
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• 1976

The lecturer pointed the agriculture in change brought about population bomb and economic development, and he appealed the scientists of soil and fertilizer to make proposals for establishing their constructive attitudes toward the situations of agriculture. The points emphasised by the lecturer for the improvement of future food situation were: fox example the elucidation of the ancient agricultural technology of Korea which is a important attempt for development of agricultural technology of Korea and Japan, and soil improvement with special attention to the efficiencies of phosphate, silicate, cations and trace elements. He showed some Japanese examples of natural pollution as both of a sufferer and an assailant of agriculture which are resulted from the high economic development, and some methods of solution, for example active application of legumes capable for fixing atmospheric nitrogen to wasted soils. He also pointed the need of lower consumption of energy and resources, and new understanding of wild plant species for the future agriculture. Some methods of other fields of sciences were emphasised for developing the soil and fertilizer researches.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.143-149
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• 1993

Ginseng root explants and calli induced from selected cell lines were cultured on modified Murashige and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical composition and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of calli, the concentrations of 2, 4-D and sucrose were the range of 1 to 3 mg/${\ell}$l and 1 to $3\%,$ respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magmesian plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng. The patterns of ginsenosides, pharmacologically useful component, were different among the cell lines and contents of ginsenosides were much higher in selected cell lines than in original cell line.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.602-608
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• 1995

The aim of the present research program was to construct an optimum fermentation system and to characterize the properties of cathepsin B inhibitor from Streptomyces chromofuscus SMF28. Glucose and casitone were proved to be good carbon source and nitrogen source, respectively. The production of inhibitor was high at lower concentration than 10 mM of inorganic phosphate. The optimum temperature and pH for the production of inhibitor were 30$\circ$C and pH 7, respectively. The production of inhibitor was related to mycelial growth and was affected by medium composition. The inhibitor in culture filtrate of S. chromofuscus SMF28 was purified by butanol extraction, silica gel chromatography, Amberlite IRC-50 (H$^{+}$ form) chromatography, preparative TLC, and preparative HPLC. From amino acid analysis and UV, IR, $^{1}$H-NMR spectroscopic analysis, the inhibitor was identified as a peptide containing valine and phenylalanine derivative.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.11a
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• pp.114-117
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• 1996

Biodegradation potential of crude oil has been studied in liquid and soil slurry culture. Studies were performed to optimize the factors affecting metabolic activity. Arabian Light(sulfur content 1%) was used as a representative crude oil and Nocardia sp. was selected as an oil degrading microorganism based on its ability to degrade and emulsify Effects of various nutritional and environmental conditions as well as emulsification and surface tension were observed. Tentative optimization of environmental and nutritional condition were as follow; pH 8, sodium nitrate as inorganic nitrogen source, yeast extract 0.05%, phosphate concentration 0.25% and glucose addition of 1.0% (w/v basis), extent of degradation to 78 %.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.2
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• pp.139-146
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• 1996

An experiment was canied out to investigate how to effect the application of nitrogen, phosphate and potassium on the vegetation and dry matter yield in the mixed sward of Ladino clover and crabgrass(Digitaria sanguinalis [L.] Scop.). The experimental sward was consisted of eight plots of non-application, K, P, PK, N, NK, NP and NPK. These plots were sown with seeds mixture of Ladino clover 5.0kg/ha and crabgrass 17.5kg/ha on 17 April 1976 in the forage experimental field of Kangwon National University, Chunchon, Korea, and were cut three times from 6 July to 4 October 1976.

• The Korean Journal of Ecology
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• v.20 no.2
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• pp.145-151
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• 1997

A census of the forest vegetation of Mt. Kaya National Park was taken with respect to the medthods of ordination and classification. Eight groups were classified by cluster analysis : Quercus mongolica, Q. mongolica-Sasa borealis, Q. serrata, Q. variabilis, Carpinus laxiflora, Cornus controversa, Fraxinus mandshurica and Pinus densiflora. Among them, the Q. mongolica group and Q. mongolica-S. borealis group, the F. mandshurica group and C. controversa group showed similar floristic compositions to each other. The interrelationship between the floristic compositon of the vegetation and soil environment was analyzed by PCA, the Q. mongolica group and the Q. mongolica-S. borealis group were distributed in areas of high CEC and total nitrogen content, while the Q. serrata. Q. variabilis. C. laxiflora and Pinus densiflora groups formed their communities in the more moderate areas of pH, soil moisture and soil organic matter. F. mandshurica and C. controversa groups were distributed in the areas of high soil moisture, soil organic matter, pH and available phosphate.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.482-486
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• 2013

Assessment of nutrient balance in region unit is important to make a decision on nutrient management in agriculture. In this study, the nutrient demand in arable land and nutrient supply from livestock manure and chemical fertilizer were estimated from pig-concentrated areas. Three regions (H, I and J) were selected on the basis of pig numbers per unit area of arable land. In H and I regions, nitrogen amount from pig manure occupied about 50% of total livestock manure. Nutrient supply was three times higher compared to the nutrient demand in each of 3 regions. Soil available phosphate of higher pig-populated area in regional unit was higher than less populated livestock area. Therefore, livestock manure-derived regional management and monitoring of soil nutrient contents is necessary for the minimization and improvement of nutrient surplus.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.506-508
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• 1986

Metabolic activity of inorganic nitrogenous compounds affects not only microbial growth but also metabolite production in fermentation technology. We have worked on the enzymes participating in ammonia assimulation of some fermentation bacteria. This paper summarizes the results on glutamine synthetase and its application in practical field. Glutamine synthetase (L-glutamate:ammonia ligase, EC. 6.3.1.2) catalyzes the formation of glutamine from glutamate and ammonia at the expense of cleavage of ATP and inorganic phosphate. The enzyme plays a dual role in nitrogen metabolism in bacteria; it is a key enzyme not only in the biosynthesis of various compounds through glutamine but also in the regulation of synthesis of some enzymes involved in the metabolism of nitrogenous compounds. The detailed works with the Eschericia coli and other enterobacterial enzymes revealed that glutamine synthetase is controlled by the following complex of mechanisms: (a) feedback inhibition by end products, (b) repression and derepression of enzyme synthesis, (c) modulation of enzyme activity in response to divalent cation and (d) covalent modification of enzyme protein by adenylylation and its cascade control. Comparative studies have also been made on the enzymes from other organisms.