• Journal of Life Science
• /
• v.6 no.4
• /
• pp.270-277
• /
• 1996

Streptococcus sp J-C1 producing bacteriocin was isolated from Kimchi. The optimum conditions for bacteriocin production by Streptococcus sp. J-C1 were evaluated. For the maximum yield of bacteriocin production by Streptococcus sp. J-C1, the cell should be harvested at the late stationary phase and the temperature, pH and NaCl concentration should be 25$\circ$C, pH 8 and without the addition of NaCl, respectively. Sucrose should be used as a carbon source and organic nitrogen such as peptone should be used as a nitorgen source for the best yield. The production of bacteriocin is related to the cell growth of Streptococcus sp. J-C1. The bacteriocin from Streptococcus sp. J-C1 was active for gram positive microorganisms such as Lactobacillus sp., Leuconoctoc sp., Lactococcus sp., Streptococcus mutans, Staphylococcus aureus amd Bacillus subtilis and also active for gram negetive bacteria such as Acetobacter aceti. Antibacterial activity of the bacteriocin was completely disappeared by protease treatment.

• Journal of the Korean Chemical Society
• /
• v.56 no.5
• /
• pp.563-570
• /
• 2012

Solid acid Mo(VI)/$ZrO_2$ with 2-10% Mo(VI) was coated on honeycomb monoliths by impregnation method. These catalytic materials were characterized by BET, $NH_3$-TPD/n-butylamine back titration, PXRD and SEM techniques. Phenyl salicylate (Salol) was synthesized via transesterification of methyl salicylate and phenol over these catalytic materials. An excellent yield (91.0%) of salol was obtained under specific reaction conditions. The effect of poisoning of acid sites of the catalytic material by adsorbing different bases and its effect on total surface acidity, powder XRD phases and catalytic activity was studied. A triangular correlation between the surface acidity, powder XRD phases and catalytic activity of Mo(VI)/$ZrO_2$ was observed. The thermally regenerated catalytic material was reused repeatedly with a consistent high yield of salol.

• Food Science and Preservation
• /
• v.3 no.2
• /
• pp.171-178
• /
• 1996

This study was carried out for the purpose of improving the persimmon vinegar. The acetic acid bacteria strain JST-3, using acetic acid fermentation was isolated from the traditional persimmon vinegar. The optimum conditions for high yield of acetic acid were studied in the shaking bath. Acetic acid bacteria was cultured at 3$0^{\circ}C$ for 4 days and transferred to persimmon alcoholic juice for acetic acid fermentation. The optimum initial acidity for acetic acrid fermentation was 1%(w/v) and the addition of glucose or yeast extract was observed to produce relatively low yield of acetic acid. Succinic and acetic acid were major organic acid in the persimmon vinegar, The contents of lactic acid which was known to increase off-flavor were very low. Sensory evaluation revealed that the persimmon vinegar prepared in this study was superior to two commercial ones in the aroma and taste.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.6
• /
• pp.138-144
• /
• 2003

A crack in a ferroelectric ceramic subjected to an electric field is analyzed. The boundary of the electrical saturation zone is estimated based on the finite-width saturation zone model, which is analogous to a finite-width Dugdale zone model for mode III. It is shown that the shape and size of the switching zone depends strongly on the boundary of the electrical saturation zone and the ratio of the coercive electric field to the yield electric field. The crack tip stress intensity factor under small scale conditions is evaluated by employing the model of electric nonlinear domain switching. It is found that fracture toughness of the ferroelectric material may be increased or decreased depending on the material property of electrical nonlinearity.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.451-451
• /
• 2000

This study aims for the optimization of process conditions in a fixed-bed catalytic reactor system with a circulating molten salt bath, in which partial oxidation of propylene to acrolein takes place. Two-dimensional pseudo-homogeneous model is adopted with estimation of suitable parameters and its validity is corroborated by comparing simulation result with experimental data. The temperature of the molten salt and the feed composition are found to exercise significant influence on the yield of acrolein and the magnitude of hot spot. The temperature of the molten salt is usually kept constant. This study, however, suggests that the temperature of the molten salt must be axially adjusted so that the abrupt peak of hot spot should not appear near the reactor entrance. The yield of acrolein is maximized and the position and the magnitude of hot spot are optimized by the method of the iterative dynamic programming (IDP).

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.17 no.1
• /
• pp.35-42
• /
• 1997

Many farmers apply cattle slurry on grassland, often in excess of crop N requirements, resulting in groundwater contamination. Our research objective was the development of grassland management systems that reduce undesirable sideeffects on other compartment of the ecosystem. Field experiment was conducted during 1991~1993 on sandy loam soil at AllgZiu south western Germany. Different sets of conditions were tested such as : zero fertilization, reduced sluny application$(l20kg N ha^{-1}yr^{-1})$, intensive sluny application(conventional sluny application, $240kg N ha^{-1}yr^{-1}$). The plots of the reduced slurry application had no significant effect on dry matter yields, digestible dry matter and net energy of herbage. Dry matter yield of zero fertilization was significantly lower than that of usual slurry application, however the content of Ca and Mg in herbage tended to increase. We conclude that reduced sluny application can be applied on grassland without adverse effects on dry matter production and quality of herbage.

• Transactions of Materials Processing
• /
• v.8 no.3
• /
• pp.252-261
• /
• 1999

The 3-dimensional finite element program is developed to analyze the non-isothermal forming processes of aluminum-alloy sheet metals. Bishop's method is introduced to solve the heat balance and force equilibrium equations. Also, Barlat's non-quadratic anisotropic yield function depicts the planar anisotropy of the aluminum-alloy sheet. To find an appropriate constitutive equation, four different forms are reviewed. For the verification of the reliability of the developed program, the computational try-outs of the non-isothermal cylindrical cupping processes of AL5052-H32 and Al1050-H16 are carried out. As results, the constitutive equation relating to strain and strain-rate, in which the constants are represented by the 5th-degree polynomials of temperature, is in good agreement with measurement. The computational try-outs can predict optimal forming conditions in non-isothermal forming processes.

• Microbiology and Biotechnology Letters
• /
• v.21 no.6
• /
• pp.609-614
• /
• 1993

The optimum conditions for the submerged mycelial culture of Lentinus edodes SR-1 were elucidated to be incubation temperature of 25C, initial pH 4.0, agitation of 300 rpm, inoculation of 10.0%(v/v), and aeration of 1.0 v/v/m in TGY medium. The optimum c/n ratio and economic yield coeffcient for the submerged mycelial culture were 13.1:1 and 0.45 respectively. As the plant growth hormones test, SCM medium containing 0.5ppm of 2,4-dicholorophenoxyacetic acid increased mycelial yield in 1.1%, but 6-benzylaminopurine was not effective.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.8 no.5
• /
• pp.291-293
• /
• 2003

Batch reactors were employed to investigate the kinetics of cellulose hydrolysis under extremely low acid (ELA) and high temperature condition. The sawdust was pretreated by Auto-hydrolysis prior to the batch reaction. The maximum yield of glucose obtained from the batch reactor experiment was about 70% for the pretreated sawdust, this occurred at 210 and 22$0^{\circ}C$. The maximum glucose yield from the untreated sawdust was much lower at these temperatures, about 55%. The maximum yields of glucose from the lignocellulosics were obtained between 15th and 20th minutes after which gradual decrease was observed.

• Macromolecular Research
• /
• v.14 no.5
• /
• pp.510-516
• /
• 2006

Lactide was produced from oligomeric PLA by back-biting reaction of the OH end groups. For optimization of the reaction conditions, the effects of temperature, pressure, PLA molecular weight, and catalyst type on the lactide synthesis were examined. The fraction of D,L-lactide decreased with increasing temperature. Among the various Sn-based catalysts, the D,L-lactide fraction was maximized when SnO was used. A higher yield with lower racemization was observed at lower pressure. The conversion of PLA was maximized at an oligomeric PLA molecular weight of ca. 1380. The yield of lactide increased but the fraction of D,L-lactide decreased with increasing molecular weight. The highest conversion with the lowest racemization degree was obtained at a catalyst concentration of 0.1 wt%. The lactide was more sensitive to racemization because of the entropic effect.