• Progress in Superconductivity
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• v.6 no.1
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• pp.41-45
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• 2004

Polycrystalline Tl-1223 superconductors with a chemical composition of (Tl, Pb, Bi)TEX>$ (Sr, Ba)<_2$$Ca_2$$Cu_3$$O_{x}$ were synthesized by the solid state reaction method. The optimum chemical composition was $Tl_{0.8}$ $Pb_{0.2}$ $Bi_{0.2}$ $Sr_{1.8}$ $Ba_{0.2}$ $Ca_{2.2}$ $Cu_3$$O_{x}$ And the optimum sintering temperature and time were $905^{\circ}C$ and 7.5h, respectively. The sample was evaluated for their superconducting properties by magnetization measurement. The critical temperature $T_{c}$ is 120 K and the critical current density $J_{c}$ (T=5K, 0T) is estimated to be ∼ $10^{5}$ A/$\textrm{cm}^2$ for $Tl_{0.8}$ $Pb_{0.2}$ $Bi_{0.2}$ $Sr_{1.8}$ $Ba_{0.2}$ $Ca_{2.2}$$Cu_3$$O_{x}$ .

• The Korean Journal of Community Living Science
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• v.19 no.4
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• pp.611-617
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• 2008

This study was conducted to examine the yield of lotus leaves and roots per one native white lotus grown in Hoesan, Muan of Jeonnam districts, which were promoted by Muan-Gun, Jeonnam as a local speciality. We planted the rhizomes with 2 internodes in a rubber pot in the middle of April. Then on September, 24, 2008, we dug out the main rhizomes and it had grown by 810cm. From the data, the leaf area was $34,442\;cm^2$, the fresh leaf weight was 1,230g, and the dry leaf weight was 235.4g. The weight of the edible fresh stalk and dry weight leaf were 1,325g and 164.3g. Yield of the white lotus root were 1,480g on Sept. 4, 3,880g on Sept. 20 and 4,172g on Oct. 18. Native white lotus are able to be harvested early as September, however, it is be better that it is harvested in the middle of October based on the yield.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.567-575
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• 2001

A methodology is developed for designing the minimum-cost water distribution network. The method is based on network simulations and an optimization scheme using genetic algorithms. Being a stochastic optimization scheme, genetic algorithms have advantages over the conventional search algorithms in solving network problems known for their nonlinearities and herculean computational costs. While existing methods focus on the design of either entirely new or parallel augmentation of network systems, the proposed method can be applied to problems having both new branches of tree-type and paralle augmentation in loops. The applicability of the method was shown through a case study for Baekryeon water supply system. The optimized design resulted in the maximum 5.37% savings compared to the conventional design without optimization, while meeting the hydraulic constraints.

• The Korean Journal of Community Living Science
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• v.19 no.1
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• pp.3-10
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• 2008

This study was conducted to gather basic data on the physiological activities of flower extracts from 4 cultivars of white lotus to promote the increase of public consumption. Four cultivars of white lotus: c.v. 'Garam', 'Choeue', 'Baekhwageonryeon', and 'Seungdal' were harvested on 14, August, 2007, and the physiological activities of flower extracts obtained by hot water extraction and ethanol extraction were examined. Total phenol content was highest in the 'Garam' flower hot water extracts, $144.2{\mu}g{\cdot}mL^{-1}$, and lowest in the 'Seungdal' flower ethanol extracts, $63.4{\mu}g{\cdot}mL^{-1}$. DPPH radical scavenging activity was highest at 2,000ppm flower extract of 'Garam' obtained by hot water extraction and ethanol extraction of 90.9% and 83.0%, respectively. Total flavonoid content in the flower extracts of 'Garam' obtained by hot water extraction and ethanol extraction showed the highest levels at $34.1{\mu}g{\cdot}mL^{-1}\;and\;33.9^{\mu}g{\cdot}mL^{-1}$, respectively. Nitrite scavenging activity at 1,000ppm flower extract was highest in 'Garam'. Extracts obtain by hot water and ethanol showed 91.3% and 80.4% activity, respectively. No significant difference in tyrosinase inhibition activity was observed among the cultivars or as a result of extraction method. Overall anti-microbial activity of the flower extracts was slightly higher in 'Garam' than in the other cultivars.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.71-78
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• 2002

With the incidence of antibiotic resistant bacteria there is increasing interest in natural products such as herb extract and probiotics to control antibiotic resistant bacteria. This study was focused on the determination of antimicrobial activity of Opuntia ficus-indica var. saboten against Salmonella enetrica serovar Enteritidis (S. enterifidis), S. enterica serovar Typhimurium (S. Typhimurium) DT 104 and Escherichia coli 0157:H7. Though bactericidal effect of 0. ficus-indica var. saboten was not observed, it had significant inhibitory activity against Salmonella spp. and E. coli O157:H7 on the Moulter Hinton agar containing its solution dissolved in deionized water. To investigate the antimicrobial activity in vivo, mice were challenged with 5. Typhimurium DT104 (3.7$\times$108 cfu/mouse) after pre-feeding 0. ficus-indica var. saboten solution. The fecal shedding of S. Typhimurium DT104 was more dramatically decreased and not detectable in feces and intestines 3 days after challenge in mice fed with 0. ficus-indica var. saboten. Antibody responses of the intestinal IgA were also significantly increased in mice fed with 0. ficus-indica var. saboten. These findings suggest that Opuntia ficus-indica var. saboten decreased the shedding of S. Typhimurium DT104 in vitro and also in the gastrointestinal tract in mice. In addition, administration of the product might enhance the mucosal immune response against S. Typhimurium DT 104. In conclusion, Opuntia ficus-indica var. saboten might be useful to control antibiotic resistant bacteria in vivo and in vitro.

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.288-299
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• 2011

Freshwater fish fauna and community structure were surveyed through 21 lakes in the Yeungnam area including Gyeongsangbukdo and Gyeongsangnamdo provinces, Korean Peninsula from April 2008 to October 2009. Among 21 lakes, 16 lakes belong to the Nakdong River and 5 are independent drainages. From the present study, 61 species (44 genera, 15 families) were collected including 32 cyprinid species (52.5%), 6 cobitid species (9.8%) and so on. The dominant and subdominant species in aspect of the number of individuals were Hypomesus nipponensis (26.6%) and Squalidus gracilis majimae (14.8%), respectively. On the other hand, in aspect of in biomass, dominant and subdominant species were Lepomis macrochirus (19.8%) and Cyprinus carpio (14.7%), respectively. Among 61 examined species, there were found 20 Korean endemic species and 2 Korean endangered species (Pseudobagrus brevicorpus and Pungitius kaibarae). P. brevicorpus was found in Yongyeonji and Yeongcheonho, and P. kaibarae in Yongyeonji. In addition, 5 exotic species were identified such as Cyprinus carpio nudus (leather carp), Carassius cuvieri, Hypophthalmichthys molitrix, Lepomis macrochirus and Micropterus salmoides. Interestingly, a bluegill L. machrochirus appeared dominant or subdominant species in 5 of 21 examined lakes. Five species introduced from the other rivers in Korean Peninsula were additionally described. In the present study, it was first reported that Micropercops swinhonis inhabits in the Nakdong river basin. The fish species diversity, evenness and dominant indices were examined, and a dendrogram based on similarity indices of inhabiting species among the 21 examined lakes was constructed and discussed.