• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.79-82
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• 1999

Using Small Angle Light Scattering (SALS), the effect of quench depth on the kinetics of phase separation for ternary solution blends was investigated. The system was composed of two polymers (polystyrene and polybutadiene) and a solvent (toluene). The analyses of the early stage of phase separation were based of the Cahn-Hilliard theory [1,5]. Apparent diffusion coefficients and the fastest mode of fluctuations were evaluated, when quench depth of the system were varied near the critical composition of polymer. In the late stage of phase separation, the domain growth showed a power law with the 1/3 exponent, i.e. $q_m(t)~t^{-1/3}$. For comparison between real images and scattering profiles with time, the image of phase domains with time were obtained by using Laser Confocal Scanning Microscopy (LSCM).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.388-395
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• 1998

This paper reports on a thermodynamic analysis for the GaN thick film growth by vapor phase epitaxy method. The thermodynamic calculation was performed using a chemical stoichiometric algorism. The simulation variables include the growth temperature in a range 400~1500 K, the gas ratios $(GaCl_3)/(GaCl_3+NH_3)$ and $(N_2)/(GaCl_3+NH_3)$. The theoretical calculation predicts that the growth temperature of GaN be in the lower range of 450~750 K than the experimental results. The difference in the growth temperature between the simulation and the experiments indicates that the vapor phase epitaxy of GaN is kinetically limited, presumably, due to the high activation energy of thin film growth.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.507-513
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• 2000

A bacteriocin-producing organism, Enterococcus sp. T7, was isolated from human fecal samples. Bacteriocin T7, named tentatively as the bacteriocin, was produced by Enterococcus sp. T7 and it inhibited some strains of Lactobacillus. Staphylococcus, Enterococcus, and Streptococcus, but not all the lactococci and gram-negative bacteria tested. Bacteriocin T7 inhibited the growth of Listeria monocytogenes Scott A, but the degree of inhibition was less than those for other sensitive gram-positive vacteria. Bacteriocin T7 in MRS broth started to produce at the middle of the exponential growth phase and the inhibitory activity reached its maximum level during the stationary growth phase. Bacteriocin T7 was stable against heat treatments, pH variations (pH 2-10), and exposure to organic solvents. The molecular weight of bacteriocin T7 was estimated to be 6.500 Da by SDS-PAGe. All these facts, including physico-chemical stabilities, small molecular size, and inhibition of Kisteria monocytogenes, indicate that bacteriocin T7 is likely to be a member of the class IIa bacteriocins.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.580-583
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• 2007

Phytase activity was examined with various bifidobacterial strains cultured statically in MRS broth at $37^{\circ}C$ for 48 hr. Seven Bifidobacterium species showed mostly an intracellular phytase activity, though their specific activities were very low. The highest specific activity was found in Bifidobacterium animalis B33 strain, among 7 bifidobacteria tested. The specific activity was highest during the exponential growth phase. Carbohydrates and the concentration of phosphorus sources had an effect on the phytase activity and bacterial growth. Glucose was the most favorable carbohydrate for the phytase activity. Phytate inhibited the cell growth, and phytase activity decreased with increase of phytate concentration. The phytase activity was even higher in the static microaerophilic growth than that in anaerobic state, despite the stimulated growth in anaerobic growth. The optimal pH ranges were comparatively broad, but the optimal temperatures were $50^{\circ}C$ for all tested strains. The phytase activity was most active at pH 6.5 and $50^{\circ}C$ for B. animalis B33 strain.

• Journal of Animal Science and Technology
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• v.52 no.1
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• pp.29-36
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• 2010

This experiment was conducted to evaluate the influence of phase feeding methods on growth performance, carcass characteristics, pork quality, and economical efficiency in growing-finishing pigs. A total of 120 crossbred pigs ([Yorkshire ${\times}$ Landrace] ${\times}$ Duroc), average initial body weight 25.23 ${\pm}$ 2.66 kg, were allotted to 5 treatments by body weight and sex in a randomized complete block (RCB) design. Each treatment had 6 replicates with 4 pigs per pen. The treatments were 1) A (fed late weaner feed during whole phase), 2) B (fed late weaner feed in growing phase and grower feed in finishing phase), 3) C (fed grower feed during whole phase), 4) D (fed grower feed in growing phase and early finisher feed in early and late finishing phase), 5) E (fed grower feed in growing phase, early finisher feed in early finishing phase and late finisher feed in late finishing phase). Commercial diets bought from private feed company were used for this experiment. During the early growing phase (6 wks), treatments A and B showed higher growth performance than that of other treatments (P<0.05). However, growth performance tended to be similar among treatments at 10 wks after feeding and there was no difference in time of market weight (13 wks). Moreover, blood urea nitrogen (BUN) concentration was lowered in treatment E than other treatments during whole experimental period (P<0.01). Carcass characteristics and pork quality were measured when body weight of pigs reached at 110.33 ${\pm}$ 2.1 kg. Days to market weight (110 kg), quality grade, pork color, and pork pH did not show any significant difference among treatments. These results suggested that phase feeding based upon growth stages of pigs showed no detrimental effects on growth performance and the pork quality. Moreover, feed cost was saved approximately 37% by phase feeding method without delaying of days to market weight compared to general conventional feeding method (B) of swine farm in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1252-1258
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• 2015

The Liangshan pig is a traditional Chinese small-sized breed; it has a relatively long feeding period and low meat production ability but superior meat quality. This study utilized three non-linear growth models (Von Bertalanffy, Gompertz, and logistic) to fit the growth curve of Liangshan pigs from an unselected, random-bred pig population and estimate the pigs most suitable slaughter weight. The growth development data at 20 time points of 275 Liangshan pigs (from birth to 250 d) were collected. To analyze the relative gene expression related to development, seven slaughter weight phases (50, 58, 66, 74, 82, 90, and 98 kg) (20 pigs per phase) were examined. We found that the Liangshan pig growth curve fit the typical S-curve well and that their growth turning point was 193.4 days at a weight of 62.5 kg, according to the best fit Von Bertalanffy model based on the goodness of fit criteria. Furthermore, we estimated that the most suitable slaughter weight was 62.5 to 74.9 kg based on the growth curve and the relative expression levels of growth-related genes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.5
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• pp.451-461
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• 2005

The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8. by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carton dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0. consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.2
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• pp.58-61
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• 2016

Bulk GaN crystals were grown by the basic ammonothermal method. The c-plane GaN templates grown by hydride vapor phase epitaxy were used as seed crystals and sodium metal, amide, and azide were added as a mineralizer. The growth conditions are at temperatures from $500{\sim}600^{\circ}C$ and pressures from 2~3 kbar. The growth rate for the c-axis was increased with increasing the operating pressure. Average dislocation density was measured $1{\times}10^5/cm^2$ by the cathodoluminescence measurement. The full-width at half-maximum of the X-ray diffraction rocking curve for (002) reflection was approximately 270 arcsec for Ga face and 80 arcsec for N face.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.47-51
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• 1998

The GaN thick films were deposited on sapphire substrates by the chloride vapor phase epitaxy (CVPE) technique suing the GaCl3-NH3-N2 chemistry. Thermodynamic simulations were carried out to predict the optimum process windows, and the results were compared with the experiments. A large difference in the growth temperature was observed between the calculation an the experiment, and it indicated that the growth of GaN by the CVPE technique is kinetically limited.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.494-503
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• 1997

We investigated the initial stages of formation of the Cu/polyimide interface using another two methods by X-ray photoelectron spectroscopy. : One, in-situ measurement with increasing of Cu deposition thickness onto polyimide(PI), the other, measurement with decreasing of Cu thickness of Cu/pI film by $Ar^+$ ion etching. From these results, we find that the chemical reactions exist in Cu/PI interface. However, the measured chemical reactions were different according to experimental method.