• Journal of Ginseng Research
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• v.30 no.1
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• pp.22-30
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• 2006

Phenolic acids of white ginseng were extracted and fractionated into free, esterified, and insoluble-bound forms. The contents of individual phenolic acids in different forms were quantified by gas liquid chromatography. Nine different phenolic acids as free, esterified, and insoluble-bound forms were identified in white ginseng. Total phenolic compounds in different forms of extracts was 0.309% (free form), 0.230% (esterified form) and 0.138% (insoluble-bound form), respectively. Total phenolic acid contents in free, esterified and insoluble-bound form were 889.3, 356.8, 1,176.9 mg/100g fraction, respectively. Ferulic acid was the predominant phenolic acid, representing 63.7% and 50.9% of total phenolic acids in esterified fom and insoluble-bound form, respectively. While caffeic acid was only detected in esterified form. At 10 mg/ml insoluble-bound form quenched 95.9% ABTS free radicals generated from 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH). Also, electron donating ability and lipid peroxidation inhibitory activity of insoluble-bound fom were higher than other fraction. All phenolic acid fractions scavenged over 80% of hydroxyl radical at 10 mg/ml.

• Food Science and Preservation
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• v.18 no.5
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• pp.700-705
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• 2011

The physicochemical qualities, antioxidant activities, and polyphenols composition of eight kinds of cloud and clear apple juice products marketed in Korea were investigated. The acidities of eight kinds of cloud and clear apple juice products were in the range of 0.299~0.556 and showed no significant difference (p<0.05). The soluble solid contents of the cloud type were higher than those of the clear type which had higher reducing sugar contents. The color value and turbidity of the cloud type were also higher, but the vitamin c contents showed no significant differences. The total phenolic contents of the cloud type (1.13~1.42 g/L) were four fold to eight fold higher than the clear type (0.12~0.32 g/L). Nine polyphenolic compounds, including chlorogenic acid, caffeic acid (-)-epicatechin, quercitrin, phloridzin, and 5-hydroxymethyl furfural (5-HMF), were isolated by HPLC analysis, and the total amount of the cloud type (319.37~985.63 mg/L) was higher than that of the clear type (92.88~214.39 mg/L). The antioxidant activities, by DPPH and FRAP assays, of the cloud type showed stronger than those of the clear type. The antioxidant activity and the color value were highly correlated with total phenolic content and polyphenols content (r>0.95).

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.194-201
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• 2010

This study was carried out to analyze vegetation and soil characteristic, and ordination of subalpine forest vegetation of Daecheongbong area, Mt. Seorak. Communities by characteristic in species composition of subalpine forest were classified into Rhododendron mucronulatum var. ciliatum - Betula ermani community group, Pinus pumila, Abies nephrolepis, Thuja koraiensis, and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community. The results of the correlation between forest communitie sand soil conditions of Daecheongbong area by DCCA ordination method are as follows: The Pinus pumila community and Thuja koraiensis community were mainly found in the high percentage area of total nitrogen, available phosphorous, organic matter in comparison with Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community. The Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community were mainly found in the high elevation area in comparison with Pinus pumila community and Thuja koraiensis community. The Pinus pumila community and Thuja koraiensis community were mainly found in the northern and northwestern direction, but Abies nephrolepis community and Rhododendron mucronulatum var. ciliatum - Betula ermanii typical community were mainly found in the southwestern direction.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.154-164
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• 2018

We investigated the ichthyofauna and fish community structure of the Mudeungsan National Park, Korea from 2014 to 2016 to prepare a conservation plan. We collected 21 species of 6 families collected from 8 survey stations through skimming nets and cast nets during the period. The dominant and subdominant species were Zacco temminckii (43.0%) and Rhynchocypris oxycephalus (15.1%), respectively. The other abundant species were Z. platypus (11.2%), Pungtungia herzi (10.1%), Squalidus gracilis majimae (8.9%), and Z. koreanus (4.5%). Among the fish collection, 13 species (61.9%) were Korean endemic species, but, endangered species and exotic species were not found. Similarity indices based on species composition and abundance showed the clear division of the fish community into two river systems (Yongsan River drainage system (St. 1-7) and Seomjin River drainage system (St. 8)). The Youngsan River system was further divided into the uppermost (St. 1, 2, 4, 6, and 7) and the upper-middle (St. 3 and 5) regions. The number of species appearing in a year was similar at 19 to 20 throughout the survey period. However, the individual number of fish in 2015 (2,670) was 20% less than that of 2014 (3,366) and 2016 (3,429), respectively. The probable reason for this decline is the rapid decline of stream level in 2015 compared to the other years. During the survey period, river works were undergoing at 3 out of 8 stations, having created disturbance in fish habitat and especially impacted on benthic fishes.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.90-109
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• 2016

This study aims to investigate the flora of Mt. Cheonma (Namyangju-si, Gyeonggi-do, Korea), including Korean endemic, rare and endangered plants. To support the biodiversity and usefulness of this investigation, we checked the red list plants, floristic regional indicator plants, climate change adaptation target plants and naturalized plants, and compared composition of plant species in Mt. Cheonma with nearby mountains. Totally, we performed 22 field investigations from April 2012 to October 2014. The number of vascular plants in this region is 433 taxa and comprised of 94 families, 266 genera, 378 species, 2 subspecies, 46 varieties, and 7 forms. Among them, there are 13 endemic plants designated by Korean Forest Service, whereas only 10 taxa are endemic species by Korean Ministry of Environment (KME). According to the IUCN criteria, there are 12 rare and endangered plants composed of 9 Least Concerned (LC), 2 Vulnerable species (VU), and one Endangered species (EN) found by Korea National Arboretum (KNA). Meanwhile, 8 taxa including 7 Least Concerned (LC) were found in Red List of KME. The floristic regional indicator plants designated by KME were 49 taxa. In addition, there are 14 taxa in The Adaptable to Climate Change Plant List designated by KNA, while only 19 taxa are naturalized plants. Generally, there are 190 common taxa in Gwangju Mountains area, and only 51 taxa are distributed in Mt. Cheonma.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.609-617
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• 2009

This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea, Pyrola incarnata, Linnea borealis and Maianthemum bifolium, completely disappeared and was replaced by sedge species, such as Carex duriuscula, C. lanceolata, C. pediformis, Poa attenuata and P. pratensis. During the research period, temperature increased by an average of $1.6^{\circ}C$ in burned stand and $1.7^{\circ}C$ in clear-cut stand compared to reference stand, but RH sharply decreased up to 15.7% in clear-cut stand. This result indicates that Larix sibirica stand became warmer and drier after forest fire and clear-cutting, and contributed to the abundance of sedge and grass species in the understory. Moreover, intense occupation of tall sedge grass after forest fire and clear-cutting had a vital role as obstacle on natural regeneration of Larix sibirica. The similarity of species composition between reference and burned stands was higher (73.6%) than between reference and clear-cut stands (63.8%). Soil moisture significantly decreased after forest fire and clear-cutting, and the extent of decrease was more severe in the clear-cut stand. The chemical properties at soil organic layer were significantly affected by forest fire and clear-cutting but not the mineral horizons. Inorganic nitrogen of the forest floor significantly decreased in the clear-cut stand ($1.1{\pm}0.4mg{\cdot}kg^{-1}$) than that of the burned ($4.5{\pm}2.3mg{\cdot}kg^{-1}$) and reference stands ($5.0{\pm}2.3mg{\cdot}kg^{-1}$). Available P of the forest floor significantly increased after fire, whereas it decreased after clear-cutting. These results indicate that existence of boreal understory vegetation, and changes in soil moisture and available P are distinct attributes applicable as ecological indicators for identifying forest degradation in Mongolia.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.339-350
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• 2009

This study was carried out to investigate distributional condition of rare plants and useful plant resources, and to verify distributional patterns of understory vegetation associated with the upper layer's vegetation structure. Total 59 families, 160 genera, 218 kinds of vascular plants were identified at the study site including 6 rare plants designated by Korea Forest Service (Lloydia triflora Bak., Trillium kamtschaticum Pall., Lilium distichum Nakai, Anemone koraiensis Nakai, Iris odaesanensis Y.N. Lee, Viola diamantica Nakai). Twenty three species of useful plant resources were also identified at the site; 8 of them showed clustered distributions and the others were prone to scatter. Actual vegetation of this study area consisted of one natural community dominated by Quercus mongolica Fisch. and three disturbed communities of Larix kaempferi (Lamb.) Carriere, Abies holophylla Max. and/or a herbaceous vegetation resulting from forest removal and strong wind of mountain top. This classification was strongly supported by cluster analysis based on the surveyed plot data. Distributional patterns of understory vegetation within forest stand were somewhat related to overstory vegetation structure, but showed a different tendency according to site condition, species composition, and competitive pressure among understory vegetation. Therefore, in order to protect the important understory components as forest genetic resources, forest treatments such as density control of overstory should be implanted based on understanding of impact on understory's dynamics and growing condition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.2
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• pp.93-100
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• 2013

Many researches have been carried out to reduce and/or to capture the major global warming gases. Especially, the hydrate formation mechanisms were intensively investigated for carbon dioxide sequestration and storage process applications. In this study, the characteristics of film-type crystal growth mechanism of carbon dioxide hydrate were comprehensively examined. Carbon dioxide hydrate crystal was formed in semi-batch type stir reactor at various pressure conditions while the temperature was fixed to be constant to reduce and minimize the guest gas solubility effects. A supply gas composition was 99.999 % of Carbon dioxide, the observation data was collected by optical microscope adopted CCD camera (Nikon DS-5M/Fi1/2M-U2). This study revealed that the guest gas pressure changes significantly altered the crystal growth mechanism and film growth rate of carbon dioxide hydrate crystal. The critical pressure of the carbon dioxide hydrate of crystal growth mechanism change was found to be 2.0 MPa. The capillary force and gas concentration gradient also significantly changed the film-type crystal growth mechanism of carbon dioxide hydrate crystal.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.20-33
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• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• Journal of Korean Home Economics Education Association
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• v.20 no.2
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• pp.31-46
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• 2008

The purpose of this study is to analyze the contents of elderly housing in the unit "Family Life & Housing" in Technology & Home Economics 9th grade textbooks. The results of this study are as follows: First, the contents, illustrations, pictures, floor-plans, graphs and tables in current unit "Family Life & Housing" varied widely among textbooks and some didn't even contain these informations. Illustrations and pictures which are suit to the content and which contain positive image of space and living should be chosen. Second, most of the contents about elderly housing were concentrated on the life cycle, three-generation housing and universal design, discussed in chapter 'utility of living space.' The unification of overlapped contents and description which don't have stereotype about elderly housing are needed. Not only the interior environment but also the exterior environment of the elders and life-support service for them should be included in the contents. Contents that reflect the change of future population composition and the ratio of three-generation household are required. The elderly housing floor plan needs to be diversified in quantity such as ones which reflect the Korean characteristics or ones which enable person an independent life.