• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.667-673
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• 2017

This study was carried out to verify the antimicrobial effect of Graviola leaves against pathogenic bacteria for the purpose of developing an antibacterial material. The extraction conditions of graviola leaves were $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, and graviloa leaves werewater extracted at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$.The extraction yields and extraction conditions were determined. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was evaluated by agar diffusion method. The extraction yields were 3.02%, 14.73% and 20.76% at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, respectively. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was found in S. epidermidis.In the samples extracted at $98^{\circ}C$, a clear zone of 13 mm was observed at 200 mg/mL and of 20 mm at 500 mg/mL. The MIC was 100 mg/mL. The higher the extraction temperature and concentration, the better was the growth inhibition effect. As a result, the natural antimicrobial activity contained in natural materials can solve the problem of resistance to antibiotics. It is considered that antimicrobial activity against S. epidermidis in skin is highly applicable to basic cosmetics and cosmetic materials.

• Food Science and Preservation
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• v.18 no.3
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• pp.310-318
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• 2011

The main objective of this study was to manufacture black onions using different methods, and to analyze the color and physiological and antioxidant activities of their water extracts. Black onions were produced via high-temperature aging (70, 80, and $90^{\circ}C$). At $90^{\circ}C$, onions with different weights (large, 90-L; medium, 90-M; and small, 90-S) and small onions with different appearances (whole, 90-S-W; cut, 90-S-C; and peeled, 90-S-P) were also produced. The colorimetry measurements showed that the extract from the 90-S-C black onion had the highest ${\Delta}E$ value among all the extracts from all the black onion groups. The extract from the 90-S-C black onion had a 3.3 times higher total phenol content than that from the $70^{\circ}C$ black onion extract (11.62 and 3.51 mg/g, respectively). The DPPH radical scavenging activities of the extracts from 90-S-W, 90-S-C, and 90-S-P were higher than those of the other black onion extracts, and the 90-S-C black onion extract had the highest level of 48.3% (at the concentration of 10 mg/ml). The 90-S-C black onion extract also had the highest level of antioxidant activities (ABTS radical scavenging activity, 0.84 mg AA eq/100 g, and nitrite scavenging ability, 49.8%). These results clearly demonstrated that 90-S-C was the best among the conditions used and that the water extract of the 90-S-C black onions had a significantly higher level of antioxidant activities than the extracts from the other black onions.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1012-1019
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• 2004

The synthesis of novel group 9 metal complexes containing the S,S'-chelate ligands, $Li_2S_2C_2B_{10}H_{10}$ (2a) and $LiS(S=PMe_2)C_2B_{10}H_{10$} (2b), is described. Two new dinuclear complexes of the type $[{(cod)M}_2(S,S'-S_2C_2B_{10}H_{10})]$ (cod = 1,5-cyclooctadiene; M = Rh (3a), or Ir (3b)) were synthesized by the reaction of chloridebridged dimers $[M({\mu}-Cl)(cod)]_2$ with one molar equivalent of the corresponding dilithium dithiolato ligand $Li_2S_2C_2B_{10}H_{10}$ (2a). X-ray crystal structure analysis of 3a revealed a dinuclear structure in which each (cod)Rh unit is attached to a distinct sulfur atom of a 1,2-dithio-o-carboranyl ligand (2a). Additionally, the electrochemical properties of 3a and 3b were investigated by cyclic voltammetry. In an analogous manner, reaction of the lithium dithiolato ligand $LiS(S=PMe_2)C_2B_{10}H_{10}$ (2b) with $Cp^{\ast}CoI_2(CO)$ produced a mononuclear dithiolato complex, $[Cp^{\ast}CoI{(S,S'-S(S=PMe_2)C_2B_{10}H_{10})}]$ (4), which was characterized by single-crystal X-ray analysis.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.39-50
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• 2017

In the coagulation/sedimentation (C/S) process of the water treatment process, the inflow of massive algal bloom causes many problems including fouling of filter media. This study was conducted to find out the way to remove the algae's harmful effects by addition of pre-treatment prior to C/S process. Many Jar-tests were conducted such as (1) ACF (Algae Coagulation Flotation) process using natural algae coagulant (Water $Health^{(R)}$), (2) ACF + C/S process and (3) C/S process with a variety of conditions using cultured algae. The average values of turbidity were (1) 0.42 NTU for ACF process, (2) 0.13 NTU for ACF + C/S process and (3) 0.25 NTU for C/S process. It was shown that the treatment efficiency of ACF process could get low turbidity results, and ACF + C/S process could achieve more efficient results than those of C/S process. Any negative effects of ACF process to the efficiency of C/S process were not observed in ACF + C/S process. In order to reduce the unfavorable effects of algae, it was found out that the introduction of ACF process in the forms of (1) ACF or (2) ACF + C/S could be one of the effective and alternative solutions.

• Korean Journal of Materials Research
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• v.7 no.12
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• pp.1063-1069
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• 1997

For me1t-spun Fe-Nd-C alloys, variation of phase development and magnetic properties with the variety of alloy compositions and production conditions were investigated. To find out whether hard magnetic $Fe_{14}Nd_2C$ is crystallized direct1y from the melt by rapid quenching, the phase development of the as-spun ribbons spun at various speed was a1so studied. For the ribbons spun at 10m/s, ${\alpha}-Fe$ was the primary crystallization phase followed by the secondary $Fe_{17}Nd_2C$. At 20m/s ${\alpha}-Fe$ was suppressed so that the primary $Fe_{17}Nd_2C$ coexisted with the secondary ${\alpha}-Fe$ and the amorphous phase. Above 30m/s the ribbons were a1most amorphous, and the amorphization was complete at 40m/s. $Fe_{14}Nd_2C$ therefore was not found in as-spun state but obtained after heat treating the ribbons. The effective temperature range ($700{\sim}900^{\circ}C$) in which $Fe_{14}Nd_2C$ can be obtained was wider than that of a cast alloy. An alloy made with the wheel speed of 20 or 30m/s yielded higher coercivities after heat treatment. In iron-rich Fe-Nd-C, the composition range in which a high coercivity (more than 10kOe) is expected is narrow, i.e., 77~78 Fe and 7~8 C(at.%).

• Journal of the Korean Mathematical Society
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• v.54 no.5
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• pp.1457-1482
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• 2017

Let S and R be rings and $_SC_R$ a (faithfully) semidualizing bimodule. We introduce and study C-weak flat and C-weak injective modules as a generalization of C-flat and C-injective modules ([21]) respectively, and use them to provide additional information concerning the important Foxby equivalence between the subclasses of the Auslander class ${\mathcal{A}}_C$ (R) and that of the Bass class ${\mathcal{B}}_C$ (S). Then we study the stability of Auslander and Bass classes, which enables us to give some alternative characterizations of the modules in ${\mathcal{A}}_C$ (R) and ${\mathcal{B}}_C$ (S). Finally we consider an open question which is closely relative to the main results ([11]), and discuss the relationship between the Bass class ${\mathcal{B}}_C$(S) and the class of Gorenstein injective modules.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.261-266
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• 1995

The survival and growth of Staphylococcus aureus and Listeria monocytogenes in fish homogenates (flounder, shrimp and oyster homogenate) and tryptic soy broth (TSB) were tested during storage at simulated ambient (35$^{\circ}C$), refrigerated (5$^{\circ}C$) and frozen (-20$^{\circ}C$) temperature. A similar growth pattern of S. aureus at 35$^{\circ}C$ was observed in fish homogenates and TSB. Survival of S. aureus decreased at refrigerated or frozen temperature and that was greater at -20$^{\circ}C$ (0.3-1.2 log reduction/6 weeks) than at 5$^{\circ}C$ (1-1.6 log reduction/3 weeks). Viable cells of L. monocytogenes increased rapidly at 35$^{\circ}C$ in flounder homogenate, shrimp homogenate and TSB but after a prolonged lag period in oyster homogenate. During 3 weeks of storage at 5$^{\circ}C$, the levels of L. monocytogenes increased 3.8-5.0 log cycles in flounder homogenate, shrimp homogenate and TSB whereas levels increased 2.2 log cycles in oyster homogenate. Viable cells of L. monocytogenes during 6 weeks of frozen storage decreased 1.5-1.8 log cycles in flounder homogenate, shrimp homogenate and TSB while decreased 2.8 log cycles in oyster homogenate.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.110-116
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• 1997

Growth curves of seven strains of lactic acid bacteria isolated from Kimchi were graphed during cultivation at 1$0^{\circ}C$, 2$0^{\circ}C$, 3$0^{\circ}C$ and 4$0^{\circ}C$ in filter sterilized Chinese cabbage juice, and then lag time and generation time at each conditions were calcurated. At 3$0^{\circ}C$, the lag time of Leu. mesenteroides subsp. dextranicum was 168 min(minutes), Leu. mesenteroides subsp. mesenteroides 204 min, Leu. paramesenteroides 612 min, Lac. bavaricus 258 min, Lac. homohiochii 228 min, Lac. plantarum 270 min and Lac. brevis 264 min. And at this temperature, the generation times of Leu. mesenteroides subsp. dextranicum and Leu. mesenteroides subsp. mesenteroides were all 36 min, Lac. bavaricus 33 min, Lac. homohiochii 39 min, Lac. plantarum 66 min, Lac. brevis 42 min and Leu. paramesenteroides 162 min. As cultural temperature was lowed from 3$0^{\circ}C$ to 1$0^{\circ}C$, all strains showed remarkable prolongations in lag time and in generation time, and the prolongations were most conspicuous in Lac. plantarum. At 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$, both the lag time and the generation time of Leu. mesenteroides subsp. mesenteroides were shorter than those of Lac. plantarum. But at 4$0^{\circ}C$, this pattern was completely inverted. As a whole lower temperatures were more favorable for the growth of Leu. mesenteroides subsp. mesenteroides, while higher temperatures were for Lac. plantarum.

• Journal of the Korean GEO-environmental Society
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• v.14 no.9
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• pp.31-37
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• 2013

In this study installation diameter, interval, area replacement ratio and ground hardness of applicable ground in C.G.S method should be mastered through surrounding ground by conducting modeling. Optimum artificial neural network was selected through the study of the parameter of artificial neural network and prediction model was developed by the relationship with numerical analysis and artificial neural network. As this result, C.G.S pile settlement and ground settlement were found to be equal in terms of diameter, interval, area replacement ratio and ground hardness, presented in a single curve, which means that the behavior pattern of applied ground in C.G.S method was presented as some form, and based on such a result, learning the artificial neural network for 3D behavior was found to be possible. As the study results of artificial neural network internal factor, when using the number of neural in hidden layer 10, momentum constant 0.2 and learning rate 0.2, relationship between input and output was expressed properly. As a result of evaluating the ground behavior of C.G.S method which was applied to using such optimum structure of artificial neural network model, is that determination coefficient in case of C.G.S pile settlement was 0.8737, in case of ground settlement was 0.7339 and in case of ground heaving was 0.7212, sufficient reliability was known.

• KSBB Journal
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• v.14 no.6
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• pp.682-687
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• 1999

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. In order to investigate the function of VB-C as inducer in other strains, Streptomyces erythraeus was used as a test strain(parent). VB-C binding receptor gene was introduced into S. erythraeus(transformant) and the production of VBs and specific VB-C binding protein were analysed in parent and transformant. When 300ng/ml of the synthetic VB-C was added at 0, 20, 44 h cultivation of the parent and at 44 h cultivation of the transformant, the initial production times a antibiotics were shortened by more than 8 and 6 h, respectively. The transformant showed strong antibiotic activity against B. subtilis. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in S. erythraeus.