• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.267-270
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• 2003

Oleanolic acid is a triterpenoid compound that exists in Oldenlandia diffusa. Recently, oleanolic acid has been noted for antitumor effect. Application of both plant growth regulators, 2,4-D and kinetin, was found to be essential for the induction of callus and suspension cells. Optimum induction condition for callus and suspension cells of Oldenlandia diffusa was determined to be 0.5 mg/L 2,4-D and 0.1 mg/L kinetin. Chromatographic separation of oleanolic acid from its derivatives was achieved using Rexchrom S5-100-ODS column. The retention time of oleanolic acid was 12.6 min and the specific content of oleanolic acid was 0.41 mg/g dry weight.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.278-281
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• 1997

Streptomyces sp. MCY-846 selected by in vitro cytotoxicity assay produced elaiophylin. Individual characteristics of the strains such as spore morphology, and physiological characteristics indicated that the strain is resembled to Streptomyces hygroscopicus. The time course of cell growth and antibiotic production was observed in the medium containing 0.5% trehalose and 0.5% soybean meal as carbon and nitrogen sources, respectively. The optimum production of elaiophylin was tested with different combinations of carbon and nitrogen sources and reached a maxima of $470{\mu}$/ml in the PC-II medium.

• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.23-33
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• 1987

To detect lepotospiral strains which produce hemolysin and determine the optimal condition for assaying hemolysin, we screened reference strains and observed some property of hemolysin. Hemolysin activity was assayed with cell free culture liquids and erythrocyte suspension. The production of hemolysin by local strains isolated in Korea was assayed and compared with that of reference strains. The hemolysin was produced by 18 strains among 38 reference strains and 3 local strains isolated in Korea. The production of hemolysin began with growth of Leptospira cultured in EMJH medium and reached maximum at stationary phase. The optimum temperature for hemolytic activity was $37^{\circ}C$. At lower temperature the activity of hemolysin was decreased progressively. The hemolytic activity was completely inactivated after :30 minutes' exposure at $56^{\circ}C$. Hemolysis pattern was "hot-cold type" which showed increased hemolysis after cold incubation. The hemolysin was most active on sheep erythrocyte and less active on ox, goat, human and guinea pig erythrocyte with the decreasing order.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.452-457
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• 1999

Several bacterial strains utilizing crude oil as their sole carbon and energy sources were isolated from marine. One of the strains named KCL-1 showed the highest degradative activity for crude oil and the best growth rate. This strain was identified as a Klebsiella sp. based on the morphological, biochemical, and physiological characteristics. The optimum cultural conditions were as follows; $32^{\circ}C$~$37^{\circ}C$ for temperature and 7.0 for initial pH. Additionally, the optimal concentration of sodium chloride was 3.0%, indicating that this strain was derived from seawater. KCL-1 could use several kinds of n-alkane hydrocarbons from octadecane to hexacosane as a sole carbon source. The degradation of crude oil by KCL-1 was stimulated by addition of octadecane in the culture. The emulsifying activity by KCL-1 was highest after 3 days of cultivation under the condition of 3.0% sodium chloride, pH 7.0 and $37^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.593-598
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• 1995

The cultural conditions of Bullera singularis were optimized for the efficient production of galactooligosaccharide (GOS), Optimum temperature was 25$\circ$C, pH was 6.0, inoculum size was over 5% (v/v), initial lactose concentration was over 5% (w/v). The GOS production increased with microbial growth. Maximum amount of 72% (w/w) GOS was obtained from the optimized medium (5% lactose and 0.75% yeast extract) in 70 hours. Seven types of GOS (3 of dimer, 2 of trimer, 1 of tetramer, and 1 of pentamer) were identified by two-dimensional TLC. A new mechanism of GOS production is proposed based on the metabolism of carbon source.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.343-346
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• 2005

The isolated strain, SC2-1 was Gram-positive, catalase positive, facultatively anaerobic, oxidase negative, motile and small rods. The strain utilized sucrose, dextrose, fructose, mannitol and maltose as a sole carbon and energy source and sodium chloride required for the bacteria growth. The radical scavenging activity of the culture supernatants was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) method. This bacterium was identified based on cellular fatty acids analysis and 16S rDNA sequencing then named Exiguobacterium sp. SC2-1. The optimum culture conditions for production of antioxidant were $25^{\circ}C,$ pH 7.8 and NaCl concentration were 4%. The modified optimal medium compositions were maltose 2.5% (w/v), yeast extract 1.5% (w/v) and $KH_2PO_4$ 0.05% (w/v). Free radical scavenging activity of under optimal culture conditions were 93%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.143-144
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• 2008

Single crystal $ZnIn_2S_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $450^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the polycrystal source of $ZnIn_2S_4$ at $610^{\circ}C$ prepared from horizontal electric furnace. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $ZnIn_2S_4$ thin films measured with Hall effect by van der Pauw method are $8.51\times10^{17}$ electron/$cm^{-3}$, 291 $cm^2$/v-s at 293 K, respectively.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.24-28
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• 2008

It expects demand of ships which equipped with JIB crane growth to continue. However, demand of JIB crane is increased, domestic shipment company imitated the design of Europe and Japan. And we need to develop the functional system of the JIB crane and modernize it. We need to find the optimum luffing angle for saving energy when JIB crane works. This study analyzed buckling load of JIB and reaction force of support point and stress of JIB according to the luffing angle through finite element analysis when JIB crane loads 40 ton weight. And this study considered the safety factor 1.8 of material. Every design condition was KS A1627 standard. This study used ANSYS 10.0.

• Journal of the Korean Ceramic Society
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• v.17 no.3
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• pp.121-128
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• 1980

In order to obtain the fundamental data for the preparation of ferroxplana $Zn_2Y(Ba_2Zn_2Fe_{12}O_{22})$, which is useful for GHz-band communication, the optimum coprecipitation condition of $Zn(NO_3)_2-6FeCl_3$ in $NH_4OH$ solution and the formation process of the hexagonal ferrite were investigated. By the hot-petroleum-drying and calcining the coprecipitated hydroxide mixture $Zn(OH)_2 +Ba(OH)_2+ 6Fe(OH)_3$, the fine and uniform powder was obtained , whose phase composition and microstructure were studied by X.R.D. and electron microscope. In results, it was found that $Zn_2Y$, BaM and $Zn_2W$ were the representative phases in calcined specimens whose activation energies of crystal growth were about 3, 8, 2.5, $5.4{\times}10^4$ J/mole , respectively. The sintered specimens would be appreciated as useful magnetic cores for the high frequency communication.

• Journal of the Korean Ceramic Society
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• v.27 no.4
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• pp.521-528
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• 1990

Li2O.2SiO2 glass-ceramics were made from the melt by the nucleation and growth treatment. The optimum nucleation temperature and time were determined from DTA curves of as-quenched and thermally treated glasses, and found to be 44$0^{\circ}C$ and 3hrs. The optical microscopic technique was also used to support this result. The volume fractions of crystals present in the partially crystallized specimens were measured using the optical microscopy and the amorphous X-ray scattering methods. The degree of crystallization increased with increasing the crystallization temperature and time. The crystalline phase identified by X-ray diffraction was lithium disilicate. As the crystallinity increased up to 95%, the transmittance of glass-ceramics was decreased linearly. It was also found that for the same heat treatment condition (575$^{\circ}C$, 30min), a thicker specimen showed higher transmittance, presumably due to less crystallinity.