• Korean Journal of Environment and Ecology
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• v.16 no.4
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• pp.345-358
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• 2003

The vascular plant species in the areas of Gonamsan and Shiribong in the Baekdudaegan were summarized as 295 texa: 89 families, 193 genus, 245 species, 44 varieties and 6 forms.10 taxa were recorded in the surveyed areas as the Korean endemic plants: Hosta capitat (Liliacease), Polygonatum lasianthum var. corenum (Liliaceae), Chloranthus japonicus (Cloranthaceae), Salix hulteni (Salicaoeae), Clematis richotoma (Ranunculaceae), Spiraea prunifolia for. simpliciflora (Rosaceae), Vicia unijuga (Fabaceae), Viola albida (Violaceae), cornus walter(Cornaceae), Weigela subsessilis (Caprifoliaceae).According to the list of Korean rare and endangered plants complied in the studied areas:Iris ensata var. spoyanea(Iridaceae), Viola albida (Vioaceae) and Aristolochia contorta (aristolochiaceae) Due to the rapid destruction and increase of visitors and the studied areas are located close to the villages, the naturalized plant species in the areas were more frequently appeared than the rare and endangered plant species.

• Journal of Powder Materials
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• v.29 no.5
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• pp.363-369
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• 2022

AlSi10Mg alloys are being actively studied through additive manufacturing for application in the automobile and aerospace industries because of their excellent mechanical properties. To obtain a consistently high quality product through additive manufacturing, studying the flowability and spreadability of the metal powder is necessary. AlSi10Mg powder easily forms an oxide film on the powder surface and has hydrophilic properties, making it vulnerable to moisture. Therefore, in this study, AlSi10Mg powder was hydrophobically modified through silane surface treatment to improve the flowability and spreadability by reducing the effects of moisture. The improved flowability according to the number of silane surface treatments was confirmed using a Carney flowmeter. In addition, to confirm the effects of improved spreadability, the powder prior to surface treatment and that subjected to surface treatment four times were measured and compared using s self-designed recoating tester. The results of this study confirmed the improved flowability and spreadability based on the modified metal powder from hydrophilic to hydrophobic for obtaining a high-quality additive manufacturing product.

• Current Research on Agriculture and Life Sciences
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• v.23
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• pp.19-31
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• 2005

This study was carried out in order to provide the basic information for the development of medicinal plants in Ulleung island, Korea. This area had very rich and diverse flora; 495 taxa with l05 familes, 231 genera, 418 species, 1 subspeies, 63 varieties and 13 forms. The 94 medicinal plants were distributed in Ulleung. They were composed of 10 endemic species, 22 rare species and 62 economic species respectively.

• Journal of Korean Neurosurgical Society
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• v.55 no.3
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• pp.178-180
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• 2014

Despite significant advances in the treatment of all forms of chronic otitis media (COM), complications still can and do occur, with intracranial complications representing the most life-threatening cases, often requiring immediate therapeutic intervention. Herein, we present a rare case of rapidly progressing facial paralysis with concomitant severe headache and ipsilateral hearing loss secondary to an otogenic brain abscess, treated with the transmastoid approach, drainage, and facial nerve decompression.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.44-56
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• 2007

The flora was summarized as 195 taxa; 73 families, 138 genera, 168 species, 23 varieties and 4 forms in Jangsoo-ri windbreak forest and 151 taxa; 63 families, 118 genera, 131 species, 18 varieties and 2 forms in Pyeongsa-ri windbreak forest. Based on the list of the rare plants by the Forest Research Institute, 3 taxa and based on the list of Korean endemic plant 4 taxa were recorded in the studied areas; Puccinellia coreensis (Gramineae), Asarum maculatum (Aristolochiaceae), Prunus yedoensis (Rosaceae), Koelreuteria paniculata (Sapindaceae), Adenophora triphylla var. hirsuta (Campanulaceae). The Specific Plant Species which is categorized by the Ministry of Environment, Korea, was summarized as 23 taxa for the 1 degree of 17 taxa, 3 degree of 5 taxa, 5 degree of 1 taxa in Jangsoo-ri windbreak forest and 22 taxa for the 1 degree of 18 taxa, 3 degree of 3 taxa, 5 degree of 1 taxa in Pyeongsa-ri windbreak forest. From the enlisted the flora surveyed, the naturalized plants were 17 taxa in Jangsoo-ri windbreak forest and 19 taxa in Pyeongsa-ri windbreak forests with the Naturalization rate was 8.7 percent and 12.6 percent, respectively. In Jangsoo-ri windbreak forest, there has been occurred many man-made impair and development without legal institution and control. So, it needs in haste institutional conservation measures and systemic database construction about function and necessity of windbreak forest. In Pyeongsa-ri windbreak forest, recently many people visited here. So, if we make eco-tour place connecting nearby coast and windbreak forest, it will contribute resident's economic profit and opportunity, concerns about windbreak forest, and necessity of conservation measures. Recently, the windbreak forests in Jangsoo-ri and Pyeongsa-ri should be bereaved windbreak forest of function by the human activities.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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• pp.27-53
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• 2013

This study is carried out to offer raw data and establish strategy for conservation and restoration of river ecosystem by objective surveying and analysing the flora and vegetation distributed in Hwang river, Gyeongsangnam-do. The flora identified in this site were 406 taxa including 95 families, 252 genera, 360 species, 3 subspecies, 40 varieties and 3 forms. The rare plants were 3 taxa including Sagittaria sagittifolia subsp. leucopetala, Hydrocharis dubia and Acorus calamus. The endemic plants were 4 taxa including Populus tomentiglandulosa, Salix koriyanagi, Paulownia coreana and Weigela subsessilis. The specific plants by floristic region were 17 taxa including Salix siuzevii, Poncirus trifoliata, Potamogeton maackianus and so forth. The naturalized plants were 39 taxa including Phytolacca americana, Chenopodium glaucum, Lepidium virginicum, Oenothera erythrosepala, Xanthium canadense, Lolium multiflorum and so forth. The invasive alien plants were Ambrosia artemisiifolia and Ambrosia trifida. The whole NI and UI were each 9.6% and 13.9%. The hydrophytes were 27 taxa including Marsilea quadrifolia, Nymphaea tetragona, Ceratophyllum demersum, Trapa japonica and so forth. In the results of growth forms of the hydrophytes, emergent species were 14 taxa, 3 taxa of floating-leaved species, 4 taxa of free-floating species and 6 taxa of submerged species. The dominant vegetations were Salix spp. community, Miscanthus sacchariflorus community, Phragmites japonica community and Phragmites communis community.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.2
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• pp.13-30
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• 2019

The purpose of this study was to investigate changes in vegetation and flora after five years through field surveys data with the Han Gang Watershed Management Committee (2013) data in order to observe natural vegetation changes in the riparian zone of Han River watershed. As a result, the flora of the riparian zone in 2012 were listed total 231 taxa, 66 families, 158 genus, 207 species, 23 varieties, and 1 forms, and in 2017, a total 247 taxa, 74 families, 174 genus, 218 species, 27 varieties, and 2 forms were identified. The number of rare plants decreased from 4 taxa in 2012 to 2 taxa in total in 2017, and the number of endemic plants increased from 1 taxa to 3 taxa. The number of specific plants by floral region decreased from 21 taxa (9.1% of all 231 taxa of flora) in 2012 to 16 taxa (6.5% of all 247 taxa of flora) in 2017. The total number of naturalized plants is analyzed to increase from 35 taxa, a naturalization rate of 15.15% (all 231 taxa of flora) and urbanization index of 11.2% (all 312 taxa of naturalized plants) in 2012 to 44 taxa a naturalization rate of 17.8% (all 231 taxa of flora) and urbanization index of 14.1%(all 312 taxa of naturalized plants) in 2017. The ecosystem disturbance species showed an increase in both number of species and cover degree grades, indicating that the riparian zone changed in a negative direction.

• Journal of the Korean Chemical Society
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• v.41 no.11
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• pp.612-638
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• 1997

The methods of separation and recovery of rare earth elements in monazite sand have been studied by the ion exchange chromatography. Both of cation and anion exchange resin were used as ion exchange resins and the solutions of EDTA, DTPA, IMDA and Ln-EDTA were used as eluents. The H+, Zn2+, Fe3+, Al3+, Cu2+, and NH4+ forms of cation exchange resin were used as retaining ions. Ln-EDTA solution was loaded on the EDTA form of anion exchange resin and separated. The Ln-EDTA solution was also used as an eluent for a selective separation of one element from the rare earth mixture solution. The size effects of resin column, the elution mechanism for the various elution types and the separation of a large amount of rare earths were studied.

• Journal of Powder Materials
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• v.25 no.1
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• pp.12-18
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• 2018

Cost-effective functional phosphor nanoparticles are prepared by introducing low-cost $SiO_2$ spheres to rare-earth phosphor ($YVO_4:Eu^{3+}$, $YVO_4:Er^{3+}$, and $YVO_4:Nd^{3+}$) shells using a sol-gel synthetic method. These functional nanoparticles are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and general photoluminescence spectra. The $SiO_2$ sphere occupying the interior of the conventional phosphor is advantageous in significantly reducing the cost of expensive rare-earth phosphor nanoparticles. The sol-gel process facilitates the core-shell structure formation; the rare-earth shell phosphor has strong interactions with chelating agents on the surfaces of $SiO_2$ nanoparticles and thus forms layers of several nanometers in thickness. The photoluminescence wavelength is simply tuned by replacing the active materials of $Eu^{3+}$, $Er^{3+}$, and $Nd^{3+}$. Moreover, the photoluminescent properties of the core-shell nanoparticles can be optimized by manipulating the specific contents of active materials in the phosphors. Our simple approach substitutes low-cost $SiO_2$ for expensive rare-earth-based phosphor materials to realize cost-effective phosphor nanoparticles for various applications.

• Journal of Climate Change Research
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• v.8 no.3
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• pp.201-211
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• 2017

This study was conducted to investigate the vascular plants which can be an indicator of environmental change in Seseok of Jirisan National Park. The purpose of this study was to find out the basic information for the subalpine species. This study showed that the area had a total 295 taxa including 63 families, 177 genus, 252 species, 2 subspecies, 36 variants 5 forms and Pte-Q was 1.7. Among them, Korea endemic plants were 15 taxa such as Abies koreana. Rare plants were 14 taxa such as Viola diamantiaca. Naturalized plants consisted of 5 taxa such as Rumex crispus. The floristic regional indicator plants found in surveyed area were 72 taxa comprising 3 taxa of grade V, 7 taxa of grade IV and 24 taxa of grade III. In summary, The subalpine plants of the survey region consisted of 37 taxa including Abies koreana and Gymnadenia cucullata. As rare plants distributed in subalpine zone respond sensitively to climate change, accuracy distribution range, environmental characteristics of habitat and population dynamics of rare plants should be evaluated quantitatively.