• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.05a
• /
• pp.408-413
• /
• 2004

High speed planning boats also have been required more and more the rational strength analysis and evaluation for the optimal structural design in respect of the structural lightness according to the high speed trend. Even though the suggestion of the simple type equation for the equivalent dynamic pressure is reasonable to design the scantling of ship structure conveniently, many research activities for more reasonable improvement of the simple design pressure, have been continued to suggest the more accurate equivalent static description of tire structural response such as the deflection and stress of hull structure. In this research, we focus on the aluminum bottom stiffened plate structure in which structural scantling is mainly depend on the local loads such as dynamic or impact pressure without other load effects and structural response for the simple dynamic equivalent pressure was investigated through the structural analysis. In order to investigate the structural response of the bottom stiffened plate structure subjected to the dynamic equivalent design pressure, linear and nonlinear structural analysis of the bottom stiffened plate structure of 4.3 ton aluminum planning boat was performed based on the equivalent static applied loads which were derived from the KR regulation and representative one among various dynamic equivalent pressure equations. From above analysis results, we found that the response such as deflection and stress of plate member was similar with the response results of one plate member model with fixed boundary, which was published previous paper and in case of KR design loading, all response of stiffened plate structure were within elastic limit. Through the nonlinear analysis, nearly elastic behavior including the slight geometrical nonlinear response was dominant but plastic local zone was appeared at $85\%$ limit load. Therefore, we can say that through tire linear and nonlinear analysis, this stiffened plate member has no structural strength problem based on the yield criteria in case within $60\%$ limit load except the other strength point of view such as the fatigue and buckling problem.

• Horticultural Science & Technology
• /
• v.19 no.4
• /
• pp.579-584
• /
• 2001

This experiment was conducted to investigate the effect of soil moisture content on cut flower quality of Gypsophila paniculata L. 'Bristol Fairy' in spring and autumn cultivations. The soil moisture potential (SMP) set point for irrigation was either -3.2 or -10.0kPa in the vegetative growth stage, and -10.0, -31.6, or -79.4kPa after the budding stage. When soil moisture reached at each set SMP point, 10 mm water was drip-irrigated. Tendency of flowering was earlier as SMP set point was lower in both vegetative growth and after budding stages. No other flower characteristics were found among other treatments. In both spring and autumn cultivations, as SMP set point was lower, the low primary branch length and upper internode length were decreased, the stem firmness was increased, and curvature of cut flower stem was decreased. Especially, in autumn, the higher the SMP set point, the higher the low primary branch than the apex, thus the paniculate inflorescence was deeply destroyed. Yield in spring cultivation was not significantly different among treatments, while that in autumn cultivation increased as the lower the SMP value. It is thought that optimal imgation points during vegetative growth and after budding stages to produce high quality cut flowers are -10.0 and -79.4kPa, respectively.

• Journal of Applied Biological Chemistry
• /
• v.55 no.3
• /
• pp.173-178
• /
• 2012

Sucrose-glucan glucosyltransferase (Gtf) is an important enzyme involved in the cavity formation process where insoluble glucan is synthesized. In this study, we purified Gtf from Streptcoccus mutans Ingbritt through ammonium sulfate precipitation, Sephadex G-150, CM-Sephadex, and DEAE-Sephadex column chromatographies. A 13-fold of purification was achieved with a total yield of 6.3%. The apparent molecular mass of the enzyme was determined to be 66 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and temperature were established to be 6.0 and $40^{\circ}C$, respectively. The enzyme activity could be inhibited to 22-59% by 1 mM $Hg^{2+}$, $Cu^{2+}$ and $Al^{3+}$, and to 68% by 1 mM EDTA. It was also inhibited 40% by 2 mM xylitol and 35-45% by 0.05% soluble chitosan, glycol chitosan, and glycol chitin. This is the first report to reveal the inhibition effect of chitin derivatives on Gtf activity, which may be further applicable to develop gargles to overcome cavity.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.4
• /
• pp.518-523
• /
• 2014

There are multiple experiments conducted with male Korean native ducks (KND) to evaluate the optimal levels of limiting amino acids (AA). In Exp. 1, a total of 450 one-d-old male KNDs were divided into five groups with six replicates and fed experimental diets with varying levels of lysine, total sulfur amino acids (TSAA) and threonine (T1, 0.90/0.74/0.70%; T2, 1.00/0.82/0.77%; T3, 1.10/0.90/0.85%; T4, 1.20/0.98/0.93%; T5, 1.30/1.07/1.01%) to 21 d of age. In Exp. 2, one-d-old male KND were received and fed commercial starter diet from hatching to 21 d of age, and then divided into five groups with six replicates and fed one of five diets varying levels of lysine, TSAA, and threonine (T1, 0.73/0.62/0.54%; T2, 0.80/0.68/0.60%; T3, 0.87/0.74/0.65%; T4, 0.94/0.80/0.70%; T5, 1.01/0.86/0.75%) during 22 to 56 d of age, respectively. The BW gain was linearly increased as dietary limiting AA levels increased to 1.20% lysine, 0.98% TSAA and 0.93% threonine. There were no significant differences in feed intake, gain:feed and uniformity among groups. In Exp. 2, the BW gain and gain:feed were not affected by dietary limiting AA levels. There were no significant differences in carcass characteristics and meat quality among groups. The growth performance and carcass characteristics did not show the significant response to increasing dietary limiting AA levels in KND during 22 to 56 d of age. In conclusion, the levels of lysine, TSAA and threonine necessary to maximize growth for starter phase were at least 1.20%, 0.98%, and 0.93%, respectively. On the other hands, KND require relatively low levels of limiting AA for late growth and carcass yield. The dietary levels of 0.73% lysine, 0.62% TSAA and 0.54% threonine appear to be adequate during growing phase.

• Journal of the Microelectronics and Packaging Society
• /
• v.23 no.1
• /
• pp.17-22
• /
• 2016

Flexible organic light-emitting diode (OLED) devices consist of multi-stacked thin films or layers comprising organic and inorganic materials. Due to thermal coefficient mismatch of the multi-layer films, warpage of the flexible OLED is generated during high temperature process of each layer. This warpage will create the critical issues for next production process, consequently lowering the production yield and reliability of the flexible OLED. In this study, we investigate the warpage behavior of the flexible OLED for each bonding process step of the multi-layer films using the experimental and numerical analysis. It is found that the polarizer film and barrier film show significant impact on warpage of flexible OLED, while the impact of the OCA film on warpage is negligible. The material that has the most dominant impact on the warpage is a plastic cover. In order to minimize the warpage of the flexible OLED, we estimate the optimal material properties of the plastic cover using design of experiment. It is found that the warpage of the flexible OLED is reduced to less than 1 mm using a cover plastic of optimized properties which are the elastic modulus of 4.2 GPa and thermal expansion coefficient of $20ppm/^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.2
• /
• pp.85-91
• /
• 1994

An attempt to adjust the standard levels of NPK fertilizers application was made with the analytical data of soil and the results of field experiments on 18 vegetable crops 1. There was a remarkable accumulation of available $P_2O_5$ and exchangeable K of soil in the periods of 1980~1990 comparing with 1960~1970. 2. New fertilizer recommendations based on the accumulation of soil components enabled to decrease fertilizer requirements of major vegetable crops. It was founded that if such new recommendations were adopted by the farmer, 0~6.0kg N/10a, 0.7~12.3kg $P_2O_5/10a$ and 2.0~9.0kg $K_2O/10a$ could be saved without affecting the yield of crops 3. The formulas of fertilizer application for crops were corrected in order to determine optimal rate of each farmer field according to chemical properties of soil.

• Journal of Life Science
• /
• v.18 no.7
• /
• pp.980-985
• /
• 2008

This study was carried out to develope an alcoholic drink by fermentation of onion extract using Saccharomyces cerevisiae. The optimal conditions for ethanol production were obtained by standing culture at $25^{\circ}C$ for 5 days with 5% inoculum volume. At the results by flask culture, the growth curve of used S. cerevisiae reached to the stantionary phase at 48 hr and the death phase at 90 hr, whereas ethanol production reached maximum at 114 hr. Under the above conditions, a large scale production was carried out. A standing culture in 5 l fermenter showed the similar results to its flask culture, but progressed 24 hr rapidly more than that of the flask culture. A fed-batch culture was performed by addition of the onionic medium supplemented with 10% (v/v) sucrose after 72 hr from the fermenting start. The fed-batch culture could prevent S. cerevisiae from entering into the death phase and maintain constant level of alcohol production. A continuous culture was able to carry out by adding per every 24 hr the onionic medium supplemented with 10% (v/v) sucrose after 72 hr from the fermenting start. Although S. cerevisiae used showed a little decreased growth, alcohol production maintained roughly the constant level at the maximum yield. To enhance the quality of this alcoholic drink, $2-O-{\alpha}-D-glucopyranosyl$ L-ascorbic acid (AA-2G) was supplemented into the onion extract of the substrate for fermentation. As resulted at this study, this alcoholic drink containing AA-2G should be used as a functional fermented alcohol drink strengthened with vitamin C.

• Applied Biological Chemistry
• /
• v.33 no.4
• /
• pp.337-342
• /
• 1990

The pretense from Halobacterium sp. was purified by ethanol precipitation and gel filtration on Sephadex G-75 and G-100. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis It's specific activity was 364units/mg protein and yield was 14% of the total activity of the culture filtrate. The Km value against casein was determined to be $4.2{\times}10^{-4}M$ by Lineweaver-Burk plot The optimal temperature and pH for the enzyme activity were $35^{\circ}C$ and pH 8.0, respectively. The enzyme was stable from 5.0 to 11.0 at relatively wide range of pH but was inactivated at the temperature above $50^{\circ}C$. $Ca^{2+}$ and $Mg^{2+}$ appeared to react as activators whereas $Fe^{3+},\;Zn^{2+},\;Cu^{2+},\;Hg^{2+}\;and\;Cd^{2+}$ as inhibitors. The enzyme activity reduced with increasing the concentration of NaCl : the apparent activity with 2M NaCl was 65% as compared with that without the salt However the enzyme was unstable without salts : the activity was lost when dialyzed against distilled water for 2hr, whereas maintained against 0.1M solution of $CaCl_2$ for 6hr.

• Applied Biological Chemistry
• /
• v.48 no.2
• /
• pp.109-114
• /
• 2005

A bacterium capable of emulsifying hydrocarbon, n-hexadecane, and decreasing surface tension of the culture media using oil collapsing method was isolated. The bacterium was partially identified as Bacillus sp. and named BJS-51. n-Hexadecane was the most effective carbon source for production of biosurfactant. Surface tension was decreased from 76 dyne/cm to 31 dyne/cm and CMD (critical micelle dilution) had the highest value of 5.7 at 3% n-hexadecane. Ammonium phosphate was the most effective nitrogen source, when C/N ratio was 60, surface tension and CMD were 29 dyne/cm and 9.2, respectively. Optimum pH and temperature were 7.2 and $30^{\circ}C$, respectively. Produced biosurfactant was extracted and purified using organic solvent extraction method and preparative HPLC systems. After analysis by various color reaction, this biosurfactant was identified as lipopolysaccharide. Surface tension and CMC (critical micelle concentration) of purified biosurfactant were 27 dyne/cm and 0.08 g/l, repectively. CMD was 9.2, so the yield of biosurfactant was about 0.74 g/l at the optimal conditions. The biosurfactant was very stable at wide range of $pH\;2{\sim}12$ with surface tension $29{\sim}31\;dyne/cm$ and showed $29{\sim}30\;dyne/cm$ of surface tension after heat treatment at $100^{\circ}C$ for 60 min.

• KSBB Journal
• /
• v.15 no.4
• /
• pp.352-358
• /
• 2000

Preparation for the simplified separation of chitosandoligosaccharides from enzymatic hydrolysate was investigated. Two different types of chitosan beads as substrate were prepared as organic-based bead by W/O emulsion method and water-based bead by alkaline treatement. The average size of organic-based bead was $200{\mu}m$, and that of water based beads were $4000{\mu}m$, $100{\mu}m$, $30{\mu}m$, in diameter respectively. Enzyme stability was maintained over 80% at PH 6 after 24 hours. The optimal condition for the production of chitosanoligosaccharides was at pH 6.0, $50^{\circ}C$ and 40U (200U/g-chitosan) According to final oligosaccharide concentration water-based bed showed the similar result with that of organic-based bead even through it had smaller surface area attacked by chitosanse than that of organic-based bead. It is probable that the structure of water-based chitosan bead was looser than that of organic-based bead so enzyme penetrated easily into the bead structure. For the oligosaccharide production versus surface area the different size of water-based beads was investigated, Maxiaml production yield was observed in the $30{\mu}m$ beads. Consequently the water-based chitosan bead was better than the organic-based bead in this reaction system.