• Journal of Plant Biology
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• v.37 no.3
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• pp.387-394
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• 1994

Effects of environmental factors of light, temperature, nitrogen sources and water stress were analyzed quantitatively on the nodule formation and nitrogen fixation activity of autumn olive plant (Elaeagnu$ umbellala Thunb.) during the seedling growth. Seedlings showed the maximum nitrogenase activity of $72.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ in the early nodulation stage. The relative growth rate and T/R ratio changed from $1.60%{\cdot}d^{-1}$ and 1.12 in the earlier stage to $3.75%{\cdot}d^{-1}$ and 2.31 in the later stage, respectively. light conditions of 20-25, 1015 and 4-6% resulted in decreases of 41, 54 and 71% of the nitrogenase activity, respectively. Nodules incubated in 15, 20, 25 and $30^{\circ}C$ showed the activities of 5.4, 24.7, 51.6 and $58.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ respectively. Pretreatment with low temperature ($15^{\circ}C$) followed incubation at $30^{\circ}C$ attained higher nitrogenase activity ($66.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$) than that with higher temperature ($35^{\circ}C$). The oxygen pressure above 16 kPa is necessary for saturation of the nodule activity, but the activity was inhibited severely by physical impact such as the exision or isolation of nodules from the root. The relative activities of early nodules grown in pH 5.5, 6.5 and 8.0 were 89, 100 and 40% and those grown in 1 and 3 mM of $NO_3\;and\;NH_4$ were 6, 1 and 68, 50%, respectively. Watering levels of 20, 50 and 100 mL during the seedling growth resulted in 35, 120 and 8 mg of nodule formation and 33.6, 58.4 and $8.4\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ of the nitrogenase activity, respectively. Water stress with 86% decrease of soil water content caused temporary wilting point of leaf and a complete disappearance of nitrogenase activity of nodules, though the water content and transpiration rate in plant were reduced to 90 and 53%, respectively.tively.

• Journal of the Korean Ceramic Society
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• v.26 no.6
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• pp.763-770
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• 1989

A very fine and pure mullite powder of the stoichiometric composition was prepared from aluminium isopropoxide and tetraethylorthosilicate by an alkoxide hydrolysis method using NH4OH as a catalytic agent. The gel powder obtained from the hydrolysis was calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$. The average particle sizes of the powders calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$ were 0.19${\mu}{\textrm}{m}$ and 0.25${\mu}{\textrm}{m}$, respectively. The specific surface areas of the powders calcined at 80$0^{\circ}C$ and 125$0^{\circ}C$ were 114.7$m^2$/g and 20.6$m^2$/g, respectively. The bending strength and fracture toughness of the mullite ceramics sintered at 1$650^{\circ}C$ were 263.1MPa and 2.30MPa.m1/2 respectively.

• Communications of the Korean Mathematical Society
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• v.37 no.3
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• pp.865-879
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• 2022

Let (M^m, g) be an m-dimensional Riemannian manifold. In this paper, we introduce a new class of metric on (M^m, g), obtained by a non-conformal deformation of the metric g. First we investigate the Levi-Civita connection of this metric. Secondly we characterize the Riemannian curvature, the sectional curvature and the scalar curvature. In the last section we characterizes some class of proper biharmonic maps. Examples of proper biharmonic maps are constructed when (M^m, g) is an Euclidean space.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.414-419
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• 1987

Cultural conditions for the polysaccharide production by Pseudomonas elodea ATCC 31461, a thermogellable polysaccharide producer, were investigated. Optimum condition for polysaccharide production were: temperature; $30^{\circ}C$, pH; 6.5, glucose; 25 g/L. nitrogen source; peptone, C/N ratio; 5.0. Maximum production and yield at this condition were ca. 32 g/L and 128%, viscosity of 1% polysaccharide solution was 837 mPas at 35/sec.. Consistency index and flow behaviour index were 2570 mPas and 0.66

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.639-643
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• 2009

In this study, the antineoplastic effects of chitosan hydrolysates were assessed. The chitosan hydrolysates showed no cytotoxicity in in vitro trials using the normal cell line, Vero E6(Africa green monkey kidney cells). The $IC_{50}$ value of the chitosan hydrolysates on Vero E6 was 1,107.95 ${\mu}g/m{\ell}$. The hydrolysates exhibited in vitro antineoplastic activity in five human tumor (lung carcinoma, bladder carcinoma, colon carcinoma, stomach carcinoma, breast carcinoma) cell lines. The $IC_{50}$ values of the hydrolysates on A549, J82, SNU-C4, SNU-1, and ZR75-1 cells were 421.06, 417.99, 445.54, 380.65 and 460.49 ${\mu}g/m{\ell}$, respectively.

• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.275-281
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• 1988

To develop cellulase and xylanase-producing strain by protoplast fusion, alkalophilic Bacillus sp. F204 and K17 were treated with NTG(N-methyl-N'-nitro-N-nitrosoguanidine) and isolated anti-biotics resistant strains of S20 (Km$^r$ , Cm$^r$) and G70 (Str$^r$). The frequency of protoplast formation was about 95% when cells of mid-log phase were treated with 200$\mu\textrm{g}$/ml Iysozyme at 37$^{\circ}C$ for 30-45 minutes. Under addition of 0.4-0.5M sodium succinate, 0.5% casamino acid, 1.5% polyvinylpyrrolidone, 25mM MgC1$_2$ and 50mM CaC1$_2$ to the regeneration medium, the regeneration frequency of Bacillus sp. F204 and K17 was 24.9% and 26.2%, respectively. The fusion frequency was 6.6$\times$10$^{-6}$ in the presence of 30% polyethylene glycol 6000 containing 50mM $Ca^{++}$ at 45$^{\circ}C$ for 5 minutes. Cellulase complex and xylanase activities of fusant were compared with parental strains.

• Korean Journal of Veterinary Service
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• v.23 no.1
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• pp.1-8
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• 2000

This study was carried out to simultaneous determination of penicillin G and chloramphenicol in livestock products by HPLC. The results obstained were as follows; 1. Penicillin G and chloramphenicol were analyzed by HPLC on symmetry $C_{18}$ column with acetonitrile-0.1 M phosphate buffer containing 0.0157 M thiosulfate (25 : 75) as mobile phase at UV 325nm and 280nm, respectively. 2. Samples were applied to a SeP-Pak $C_{18}$ cartridge, from which eluted penicillin derivatized with 2 M 1,2,4-triazole containing 0.001 M mercuric chloride. 3. The average recovery rates of penicillin G and chloramphenicol were 81.8% and 80.3%, respectively, and the detection limits were 5 ppb (5$\mu\textrm{g}$/kg: 7.9IU/kg) for penicillin G and chloramphenicol in porcine and bovine muscle.

• KSBB Journal
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• v.17 no.6
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• pp.509-514
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• 2002

Experiments were carried out to optimize the fermentation conditions for the production of erythritol by salt-tolerant mutant, Candida magnoliae M26. The optimum conditions of erythritol production showed a 1.0 vvm aeration and 500 rpm agitation at 28$\^{C}$ with an initial medium pH of 7.0. The pH control during the fermentation did not improve the erythritol yield and productivity. The maximum erythritol concentration of 143.3 g/L was obtained with 57% yield and 0.70 g/L-h productivity from 250 g/L of glucose and 5 g/L of yeast extract under an optimum fermentation conditions. The medium containing 0.5 M KCl or 0.5 M NaCl enhanced the production of erythritol and glycerol. However, glycerol production increased and erythrtiol production decreased by increasing the concentration of NaCl or KCl.

• Journal of Aquaculture
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• v.15 no.3
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• pp.131-138
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• 2002

Fed on commercial flounder diet at 20, 23 and $26^{\circ}C$ in semiclosed culture system for 32 weeks, the juvenile red drum (1.2 g) showed linear increase in daily feeding rate (DFR), growth (g/fish) and specific growth rate (SGR) with increasing temperature. In the second experimental series, the young red drum (214 g), cultured at densities of 2.16, 4.24 and 6.40 kg/$m^3$ in flow-through tanks at water temperatures from 12.3 to $27.2^{\circ}C$ for 25 weeks, grew faster at the stocking density of 2.16 kg/$m^3$ than at the densities of 4.24 and 6.40 kg/$m^3$ the difference in growth observed at the stocking densities of 4.24 and 6.40 kg/$m^3$ was not significant. The DFR and SGR were also significantly higher for the density group of 2.16 kg/$m^3$. Briefly, growth of the red drum increased with increasing tested range of temperature and was also faster with decreasing stocking density. However, the total growth (g/tank) increased with increasing stocking density.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.631-637
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• 2018

In 5G mobile communication, it is necessary to provide different mobility to user equipments(UE) that do not require mobility management or need limited mobility management. In this paper, we propose a two-layer mobility management system that classifies multiple MTC devices with similar mobility levels into c-MTC and m-MTC groups. In order to improve the energy efficiency and service life by reducing the number of control signals generated when TAU is performed, the group header typically performs a Tracking Area Update(TAU) request and adjusts the periodic TAU update period according to the mobility level. The TAU update period of the m-MTC is set to 54 minutes proposed by the 3GPP standard and the c-MTC is set to 12 minutes. Compared to when the UEs perform TAU individually, it is found that the number of control signals decreases by 33% when the MME is not changed and by 49% when the MME is not changed in the m-MTC or c-MTC group.