• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.4
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• pp.268-274
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• 2015

Weld overlay was first used in power plants in the US in the early 1980s as an interim method of repairing the welds of flawed piping joints. Weld overlaid piping joints in nuclear power plants must be examined periodically using ultrasonic examination technology. Portable phased array ultrasonic technology has recently become available. Currently, the application of preemptive weld overlays as a mitigation technique and/as a method to improve the examination surface condition for more complex configurations is becoming more common. These complex geometries may require several focused conventional transducers for adequate inspection of the overlay, the original weld, and the base material. Alternatively, Phased array ultrasonic probes can be used to generate several inspection angles simultaneously at various focal depths to provide better and faster coverage than that possible by conventional methods. Thus, this technology can increase the speed of examinations, save costs, and reduce radiation exposure. In this paper, we explain the general sequence of the inspection of weld overlay and the results of signal analysis for some PAUT (phased array ultrasonic testing) signals detected in on-site inspections.

• Economic and Environmental Geology
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• v.53 no.4
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• pp.397-411
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• 2020

The Cretaceous Yucheon Group is volcano-sedimentary successions that are formed by volcanic activities of the Gyeongsang Volcanic Arc. Lack of the detailed field researches on the Yucheon Group results in poor understanding of the formation time and the tempo-spatial development of the volcanic arc. Also, this causes difficulties to reconstruct the depositional history from the Sindong and Hayang groups to the Yucheon Group. In this study, we conducted field research targeting to the interface between topmost part of the Hayang Group and the lowermost part of the Yucheon Group from Hyeonpoong to Bugok areas. We also identified depositional timing of the lowermost part of the Yucheon Group using SHRIMP U-Pb zircon age dating. This Yucheon Group is composed of tuff and lapilli tuff, conformably overlying the Jindong Formation. The results of SHRIMP U-Pb zircon age are 97 to 96 Ma, indicating cessation of deposition of the Hayang Group at 97 to 96 Ma by input of pyroclastic materials into the Jinju Subbasin during the explosive volcanic eruptions from the Gyeongsang Volcanic Arc. In comparison with field researches and results of LA-ICP-MS zircon U-Pb age dating (88-85 Ma) of the lowermost part of the Yucheon Group in Gyeongju areas, the volcanic activities that formed Yucheon Group and their influence ranges varied tempo-spatially. This is probably due to distance difference from the volcanic arc or establishment of the paleo-drainage system from the Gyeongsang Volcanic Arc to nearby lowlands.

• Applied Microscopy
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• v.22 no.2
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• pp.1-14
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• 1992

This experiment was performed to study the morphological responses of the parafollicular cells of rat following X-ray irradiation. Male rats were divided into normal and experimental groups. The head and neck region of the rat, under sodium thiopental anesthesia, was exposed to 3,000 rads or 6,000 rads of radiation in a single dose, respectively. The source was a Mitsubishi Linear Accelerator ML-4MV. The target to skin distance was 80 cm, and the dose rate was 200 rads/min. The rate of experimental groups were sacrificed on the 6th hour, 2nd and 6th day after X-ray irradiation. Pieces of the tissue taken from the thyroid gland were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde (0.1M Millonig's phosphate buffer, pH 7.3), and in 1% osmium tetroxide (0.1M Millonig's phosphate buffer, pH 7.3), and embedded in araldite mixture. The ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100 CX-II electron microscope. The results were as follow; 1. Two types of the parafollicular cells, according to their electron densities, were found, i. e., light cells and dark cells. 2. Three types of the parafollicular cells, according to their sizes of secretory granules were found, i.e., small granule cells ($85nm{\pm}20.1;64{\sim}102nm$), medium granule cells ($120nm{\pm}26.5;77{\sim}179nm$), and large granule cells ($165nm{\pm}25.7;128{\sim}189nm$). 3. The differential ultrastructural changes of the cells according to their cell types, i.e., dark and light cell, or small, medium and large granule cells, were hardly observed in the time and dose range covered by this study. 4. The morphological changes of the parafollicular cells were not pronounced after exposure to 3,000 rads of X-ray. 5. Swollen cisternae of the granular endoplasmic reticulum and partial cytolysis were observed after exposure to 6,000 rads of X-ray. 6. Above results suggest that the parafollicular cells showed the alterations of mitochondrial and granular endoplasmic reticular swelling, and partial cytolysis, but only in doses of 6,000 rads.

• Herbal Formula Science
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• v.19 no.1
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• pp.195-205
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• 2011

Objectives : Ecklonia cava is brown alga(Laminariaceae) which grows is sea, it has antioxidant, diarrhea and anticoagulant effect. In this study, the effect of ethanol extract of Ecklonia cava (EC) on peptidoglycan(PGN) -induced NO production in RAW 264.7 cells was investigated. Methods : In the present study, IL-6 production was measured using the enzyme-linked immunosorbent assay(ELISA), prostaglandin $\E_2$($\PGE_2$) production was measured using the EIA kit, and inducible NO synthase(iNOS), cyclooxygenase-2(COX-2), and mitogen-activated protein kinase(MAPK) activation, as determined by western blot analysis and reverse transcription -polymerase chain reaction(RT-PCR). Results : EC inhibited PGN-induced NO and IL-6 production. Consistent with these observations, the protein expression of iNOS and COX-2 were inhibited by EC. Moreover, EC suppressed the phosphorylation of extracellular signal-regulated kinase(ERK) 1/2 in PGN-induced RAW 264.7. Conclusions : These results suggest that EC has inhibitory effects on PGN-induced $\PGE_2$, NO, and IL-6 production, as well as the expressions of iNOS and COX-2 in the murine macrophage. These inhibitory effects occur through blockades on the MAPKs phosphorylation.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.9-22
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• 1993

To evaluate the protective effects of calcium antagonists, oxygen radical scavengers and excitatory amino acid (EAA) antagonist on the ischemic brain damage, we induced in vitro ischemic condition (namely, lack of oxygen and glucose) to rat hippocampal slices. And the degree of ischemic damage was determined by assaying changes in biochemical parameters such as ATP content and lactate ralease, MDA production in the presence or absence of the various drugs. During experimental ischemia for up to 60 min, ATP content was decreased and the amount of lactate release was markedly increased time-dependently. By changing the reaction medium which contained oxygen and glucose those biochemical parameters were recovered. But the recovery was not complete in this experimental condition. In the same ischemic conditions verapamil and vitamine E prevented the decrease of ATP content and the increase of lactate release from the slices. And verapamil and diltiazem decreased MDA release to the reaction medium. Superoxide dismutase (SOD) and MK-801 (as EAA receptor antagonist) protected the decrease of ATP content and reduced MDA release in 20 min ischemic condition, but glutathione affected ATP content and lactate release at the same condition. When oxygen and glucose were resupplied for 20 min after ischemic condition, verapamil showed the protective effect on the changes of ATP content and lactate release, and vitamine E decreased lactate release (at 20 min ischemia) and MDA release (at 60 min ischemia). These results showed that calcium antagonist and vitamine E protect the ischemic biochemical changes from rat hippocampal slices and calcium antagonist is more potent than vitamine E to protect the ischemical brain damege.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.468-475
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• 2005

Biofilters packed with various materials have emerged as a sustainable technology for the treatment of volatile organic compounds (VOCs); however, problems including low performance and clogging are commonly encountered. Recently, a bioactive foam reactor (BFR) using surfactants has been suggested to ensure efficient and stable VOCs removal performance. This study was mainly conducted to investigate the feasibility of BFRs using toluene as a model compound. Prior to bioreactor studies, a series of bottle tests were used to select a suitable surfactant for the BFR application. Experimental results of the batch bottle tests indicated that TritonX-100 was the most appropriate one among the surfactants tested, since it showed a minimal effect on the toluene biodegradation rate while the other surfactants lowered the toluene biodegradation rate significantly. Using the selected surfactant, the BFR performance was determined by changing operating parameters including gas residence time and toluene loading. As the gas residence time increased from 0.5 minutes to 2 minutes, the toluene removal efficiency increased from approximately 50% to 80%. In addition, an increase of the toluene loading from $38\;g/m^3/hr$ to $454\;g/m^3/hr$ resulted in a decrease of toluene removal efficiency from approximately 70% to 20%. The BFR had a maximum elimination capacity of $108\;g/m^3/hr$ for toluene, which was much higher than those generally reported in the literature. The high toluene-elimination performance indicates that the BFR be a potential alternative to the conventional, packed-type biofilters. However, the limitation of toluene solubilization and foam stability at either high or low gas flow rate are still problems to be challenged.

• Korean Journal of Plant Resources
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• v.30 no.1
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• pp.110-123
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• 2017

The authors reviewed the history of creation and management, purposes, extents, methods of creation, planting species and mediums, structure of vegetation layers and legal management, etc. of coastal forests of Korea. Since the Goryeo dynasty, the inhabitants in the coastal regions has long been aware the safety from natural disasters and the local governments manages for the defence and natural disasters, and collaboration among GO and NGOs, as well as enterprises are participating to the conservation of coastal forests in Korea. The purposes of creation and management of coastal forests in historical aspects are prevention of disasters, safety by the Fengsui, military uses, and timber productions, but partly as the places for religious beliefs, safety from diseases and fires, increasing of forest products and fishes, as well as tourists, improving of amenity and landscapes and recreation, inherits of traditional culture, habitats for wildlife, and ecological corridors, etc. The inhabitant in the coastal region who experienced frequent natural disasters has strong supports for the conservation of coastal forest and as a natural resources to inherits to the coming generations as the coastal forests has high values of academic researches on human society, culture, ecology and recreational uses, etc. The extensive overall researches on the creation and managements of coastal forests, as well as cultural tradition in the coastal forests of Korean peninsula are critically essential.

• Korean Journal of Plant Taxonomy
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• v.40 no.4
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• pp.274-277
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• 2010

This study was performed to report the augmented wild populations of Forsythia koreana (Rehder) Nakai and Abeliophyllum distichum Nakai in Korea. Forsythia koreana was found in Budong-myeon, Cheongsong-gun, Gyeongsangbuk-do. The overall size of the natural habitat of Forsythia koreana is $5m{\times}5m$. A total of 12 individuals were recorded in the wild, and 3 of them were in the seedling stage. The wild habitat is in a secondary forest, which is co-dominated by Pinus densiflora Siebold & Zucc and Robinia pseudoacacia L, with 15% coverage. The coverage of the shrub layer is 40% and is dominated by Spiraea prunifolia for. simpliciflora Nakai. The natural habitat of Abeliophyllum disitichum, which is recorded in Uisong-up, Gyeongsangbuk-do, is distributed in sites characterized by boulders along streams, with a patchwork of 15 scattered areas over a habitat size of $50m{\times}15m$. Quercus variabilis Blume is a dominant species in this habitat, with this species dominating at the sub-tree layer. Celtis aurantiaca Nakai also dominates at the shrub layer. The natural ranges of these two species in Korea were mapped based on the terms of the extent of occupancy (EoO).

• Korean Journal of Environment and Ecology
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• v.6 no.1
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• pp.12-24
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• 1992

The application of island biogepgraphy and habitat fragmentation theory to protected area management in Korea is discussed. The accelerating destruction and degradation of natural habitats, with the associated erosion of biodiversity, demands and urgent response and a critical review of attitudes to protected area management. The flora of Korea will continue to change in both distribution and status in response to these man induced changes. The conservation and management of ecosystems, because of the variety of threats and the varying levels of biodiversity to be conserved, requires an integrated approach. Such an approach assesses the variety of threats, prevalent and potential, and responds with a strategy combining habitat, species and population management. The application of island biogeography, habitat fragmentation and edge effects theory to conservation strategies in Korea will assist in the understanding of the dynamic relationships between the isolation. degradation and fragmentation of surviving habitat patches. The application of such approaches is discussed with recommendations made for the adoption of an increasingly scientific approach to plant conservation based upon a knowledge of the conservation status and distribution characteristics of the Korean flora. Such data combined with demographic studies on topics such as Minimum Viable Population Size will allow an integrated approach to plant and habitat conservation to progress.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.8
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• pp.1073-1078
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• 2011

Changes of antioxidative components and activity of fermented tea manufactured by Bacillus subtilis, Saccharomyces cerevisiae, and Lactobacillus bulgaricus were evaluated during the fermentation period. The ascorbic acid content in the fermented tea was relatively lower (43.62~62.84 mg%) than that of green tea (66.74 mg%) during the entire fermentation period. The tea fermented by L. bulgaricus, which had the least contact with air, showed less change in ascorbic acid content. The polyphenol content of green tea was 14.88%, whereas that of fermented tea was 11.54~14.12% and it decreased during the fermentation period. The amount of flavonoids in green tea was 7.78 mg%, whereas that of fermented tea was 4.33~7.88 mg%. DPPH radical scavenging activity and ABTS reducing activity of green tea were 87.47% and 203.22 AEAC mg% (ascorbic acid equivalent antioxidant capacity), respectively, whereas those of fermented tea were lower than green tea. Results indicated that the antioxidative components and activity of fermented tea were lower than those of green tea during the fermentation period. But, when the sensory and hygienic quality are considered, fermented tea can be one of the higher quality tea products on the market.