• Korean Journal of Plant Resources
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• v.22 no.2
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• pp.180-194
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• 2009

588 taxa of vascular plants including 121 families, 399 genera, 510 species, 67 varieties, 2 subspecies, 7 forma, and 2 hybrid species were investigated in Mt. Cheonsung. Among them, 116 species were newly added in this research. The area for Gyeongbu High-speed Railway passes Mujechi 3, 4, 5, and 6 and Daeseongsa around the wetlands were investigated 6 species of rare and endangered plants, 9 species of endemic plants and 37 species of special flora plants in Mt. Cheonsung. Appear due to the construction of the Gyeongbu High-speed Railway vegetation changes, especially about the impact of wetland plants for long-term monitoring is expected to need. Moreover, plant preservation plan about water source change in upper wetland should be established.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.2
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• pp.67-90
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• 2024

The purpose of this study is to present the ecological data for conservation and management of three wetlands by surveying the vascular plants in Ganam reservoir, Ahnshim wetland and Jeomsae swamp. The whole taxa of vascular plants were 376 taxa including 90 families, 252 genera, 341 species, 7 subspecies, 24 varieties, 2 forms, 1 hybrid and 1 cultivar, and the planted species were 66 taxa including Ginkgo biloba and so on. The rare plants were 7 taxa including Euryale ferox(VU), Aristolochia contorta(LC), Koelreuteria paniculata(VU), Sagittaria trifolia(DD), Hydrocharis dubia(LC), Ottelia alismoides(LC) and Sparganium stoloniferum(VU). The Korean endemic plant was 1 taxon of Lespedeza maritima. In total, there were 21 taxa of floristic target species including 1 taxon of garde V, 2 taxa of grade IV, 6 taxa of grade III, 5 taxa of grade II and 7 taxa of grade I . The hydrophytes were 51 taxa including 36 taxa of emergent species, each 6 taxa of floating-leaved and submerged species and 3 taxa of free-floating species. The invasive alien plants were 79 taxa including 75 taxa of naturalized plants and 4 taxa of casual alien plant. The ecosystem disturbing species 6 taxa including Sicyos angulatus, Ambrosia artemisiifolia, Lactuca seriola, Symphyotrichum pilosum, Paspalum distichum and Humulus scandens.

• Journal of Powder Materials
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• v.20 no.2
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• pp.107-113
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• 2013

In this study, the microstructure and valuable metals dissolution properties of PDP waste panel powders were investigated as a function of milling parameters such as ball diameter size, milling time, and rotational speed during high-energy milling process. The complete refinement of powder could achieved at the ball diameter size of 5 mm due to sufficient impact energy and the number of collisions. With increasing milling time, the average particle size was rapidly decreased until the first 30 seconds, then decreased gradually about $3{\mu}m$ at 3 minutes and finally, increased with presence of agglomerated particles of $35{\mu}m$ at 5 minutes. Although there was no significant difference on the size of the particle according to the rotational speed from 900 to 1,100 rpm, the total valuable metals dissolution amount was most excellent at 1,100 rpm. As a result, the best milling conditions for maximum dissolving amount of valuable metals (Mg: 375 ppm, Ag 135 ppm, In: 17 ppm) in this research were achieved with 5 mm of ball diameter size, 3min of milling time, and 1,100 rpm of rotational speed.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.604-619
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• 2016

This study is aimed at identifying the distribution of vascular plants growing at Byeollipsan(Mt.), Bongchunsan (Mt.) and Gucksoosan(Mt.) in Ganghwa isand. Field surveys were conducted for each season from March 2015 to October 2015. The flora of study area were found to be of 455 taxa, 93 families, 280 genus, 392 species, 4 subspecies, 53 varieties and 6 forma. Rare plants were found to be of 3 taxa. Among them, rare plant species consisted of endangered species (EN degree):1 (Thalictrum simlex var. brevipes Hara), vulnerable species (VU degree): 2 (Wikstroemia trichotoma (Thunb.) Makino, Scorzonera albicaulis Bunge), respectively. In all the surveyed areas, a total of 6 taxa (Clematis brachyura Maxim. etc.) were found to be endemic to Korea. The floristic special plants found in the surveyed areas were 1 taxa of grade Ⅴ, 4 taxa of grade Ⅳ and 8 taxa of grade Ⅲ, respectively. The naturalized plants were identified as 29 taxa and included Fallopia dumetorum (L.) Holub, Ambrosia artemisiifolia L., Aster pilosus Willd. etc..

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.121-125
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• 2015

Distribution of rare earth metals (REMs) and rare valuable metals (RVMs) contents in coal ashes (fly ash, bottom ash, and pond ash) and leachate from 11 coal-fired power plants in Korea were investigated. Coal ashes and leachates were found to contain important REMs and RVMs such as Yttrium (Y) and Neodymium (Nd), which was in the range of 23~75 mg/kg. However, it still requires developing effective recovery and separation methods in order to utilize REMs and RVMs in ash and leachate. Recovery of valuable elements (Y and Nd) from various and extensive ash sources (8.21 million tons/year in 2013) can provide the existing power plants with additional profit; therefore, it can significantly improve economics of the power plants.

• Korean Journal of Oriental Medicine
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• v.14 no.3
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• pp.49-56
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• 2008

Glehnia littoralis Fr. Schmidt et Miquel is an important medicinal plants in East Asian countries. This plant species naturally distributed in Korea, Japan, China, and Taiwan, but it is a rare plants living in the coastal dune in Korea. To investigate the genetic variation, genetic diversity and genetic evolutionary relationships of 14 different geographical G. littoralis, ITS sequence and random amplified polymorphic DNA (RAPD) were analyzed. On the basis of ITS sequences, it was clearly showed that the ITS1 and ITS2 sequences among 14 populations are identical regardless of geographical origin excepting 2 bp in pair-wise comparison of ITS1. Furthermore, RAPD results also showed that 14 different geographical G. littoralis produce various polymorphic patterns without critical relationship among neighboring regions. These combined results suggest that the geographical variation and genetic evolution of G. littoralis is stable and provide important information on genetic diversity, and conservation of this rare plant species in situ and ex situ.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.373-379
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• 2017

Seismic probabilistic safety assessments are used to help understand the impact potential seismic events can have on the operation of a nuclear power plant. An important component to seismic probabilistic safety assessment is the seismic hazard curve which shows the frequency of seismic events. However, these hazard curves are estimated assuming a normal distribution of the seismic events. This may not be a strong assumption given the number of recorded events at each source-to-site distance. The use of a normal distribution makes the calculations significantly easier but may underestimate or overestimate the more rare events, which is of concern to nuclear power plants. This paper shows a preliminary exploration into the effect of using a distribution that perhaps more represents the distribution of events, such as the t-distribution to describe data. The integration of a probability distribution with potentially larger tails basically pushes the hazard curves outward, suggesting a different range of frequencies for use in seismic probabilistic safety assessments. Therefore the use of a more realistic distribution results in an increase in the frequency calculations suggesting rare events are less rare than thought in terms of seismic probabilistic safety assessment. However, the opposite was observed with the ground motion prediction equation considered.

• Korean Journal of Plant Taxonomy
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• v.52 no.1
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• pp.24-28
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• 2022

Pteris griffithii Hook., one of the rarest fern species on the Indian subcontinent, is reported from Bhutan for the first time. The identity of this species was confirmed through morphological determination at the National Herbarium (THIM) of the National Biodiversity Centre (NBC) of Bhutan. It was found only in one location, in Gyelpozhing in eastern Bhutan, at an elevation of 521 m a.s.l. on 10 January 2016. Given that a very limited study of this species was conducted, the knowledge baseline with regard to its distribution is poor. It is also reported that this species has not been found for several years. The species is also considered to be very rare or critically endangered in some countries; however, there are no assessments on the International Union for Conservation of Nature (IUCN) Red List for this particular species. This paper attempts to provide baseline information considering its rarity and data deficiency. This species is also reported from the adjacent neighboring Indian state of Arunachal Pradesh as very rare, and also from Myanmar; however, confirmation of its presence in China is not clear at this time. Therefore, considering its data deficient status, we attempt to document it scientifically to create a knowledgebase pertaining to this particular species. Concurrently, this species merits further research to understand its distribution patterns in Bhutan and any related anthropogenic threats.

• Journal of Powder Materials
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• v.17 no.2
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• pp.88-100
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• 2010

• Korean Journal of Plant Taxonomy
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• v.41 no.3
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• pp.280-286
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• 2011

The natural habitats and distribution of five rare plants were recently discovered in Korea. Salomonia oblongifolia DC., which grows in mountain wetlands, was found in Gijang-gun, Busan, Gokseong-gun, Jeollanam-do, and Shinan-gun, Jeollanam-do. Glaux maritima var. obtusifolia Fernald, which grows along the coast, was found in Yangyang-gun, Gangwon-do, Pohang-si, Gyeongsangbuk-do and Buk-gu, Ulsan. Tillaea aquatica L. and Limosella aquatica L., which was previously not known to be present in Korea, were discovered in Gijang-gun, Busan for the first time. Apocynum lancifolium Russanov, which has a narrow distribution range in Korea, was also found in Samcheok-si, Gangwon-do, Ansan-si, Gyeonggi-do, Siheung-si, Gyeonggi-do, Jung-gu, Incheon, Yeongdeok-gun, Gyeongsangbuk-do and Shinan-gun, Jeollanam-do.