• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.83-115
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• 2013

Erroneous fission-track (FT) ages caused by an inappropriate calibration in the initial stage of FT dating were redefined by re-experiments and zeta calibration using duplicate samples. Revised FT zircon ages newly define the formation ages of Yucheon Group rhyolitic-dacitic tuffs as Late Cretaceous to Early Paleocene ($78{\pm}4$ Ma to $65{\pm}2$ Ma) and Gokgangdong rhyolitic tuff as Early Eocene ($52.1{\pm}2.3$ Ma). In case of the Early Miocene volcanics, FT zircon ages from a dacitic tuff of the upper Hyodongri Volcanics ($21.6{\pm}1.4$ Ma) and a dacitic lava of the uppermost Beomgokri Volcanics ($21.3{\pm}2.0$ Ma) define chronostratigraphies of the upper Beomgokri Group, respectively in the southern Eoil Basin and in the Waeup Basin. A FT zircon age ($19.8{\pm}1.6$ Ma) from the Geumori dacitic tuff defines the time of later dacitic eruption in the Janggi Basin. Based on FT zircon ages for dacitic rocks and previous age data (mostly K-Ar whole-rock, partly Ar-Ar) for basaltic-andesitic rocks, reference ages are recommended as guides for stratigraphic correlations of the Miocene volcanics and basements in SE Korea. The times of accumulation of basin-fill sediments are also deduced from ages of related volcanics. Recommended reference ages are well matched to the whole stratigraphic sequences despite complicated basin structures and a relative short time-span. The Beomgokri Group evidently predates the Janggi Group in the Eoil-Waeup basins, while it is placed at an overlapped time-level along with the earlier Janggi Group in the Janggi Basin. Therefore, the two groups cannot be uniformly defined in a sequential order. The Janggi Group of the Janggi Basin can be evidently subdivided by ca. 20 Ma-basis into two parts, i.e., the earlier (23-20 Ma) andesitic-dacitic and later (20-18 Ma) basaltic strata.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.191-198
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• 2011

In this study, antioxidative effects and inhibitory effects of Geum aleppicum Jacq. extracts on tyrosinase and elastase were investigated. The ethyl acetate fraction of G. aleppicum Jacq. extract ($4.70\;{\mu}g$/mL) showed the most prominent free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity (FSC50). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of some G. aleppicum Jacq. extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The ethyl acetate fraction showed the most prominent ROS scavenging activity ($0.22 \;{\mu}g$/mL). The protective effects of extract/fraction of G. aleppicum Jacq. against the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The G. aleppicum Jacq. extracts suppressed photohemolysis in a concentration dependent manner ($1{\sim}25{\mu}g$/mL), particularly the ethyl acetate fraction exhibited the most prominent celluar protective effect (${\tau}_{50}$, 416.20 min at $10 \;{\mu}g$/mL). The inhibitory effect of G. aleppicum Jacq. extracts on tyrosinase and elastase were investigated to assess their whitening and anti-winkle efficacy. The half maximal inhibitory concentration ($IC_{50}$) of the ethyl acetate fraction on tyrosinase was $95.23\;{\mu}g$/mL. The $IC_{50}$ of 50 % ethanol extract and the ethyl acetate fraction on elastase were $6.27 \;{\mu}g$/mL and $4.31 \;{\mu}g$/mL, respectively. These results indicate that extract/fraction of G. aleppicum Jacq. can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. Especially the ethyl acetate fraction of G. aleppicum Jacq. extracts could be applicable to new functional cosmetics for antioxidant, antiaging.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.143-152
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• 2011

In this study, the antioxidative activity, inhibitory effects on tyrosinase and elastase, and active components of Quercus salicina Blume extracts were investigated. Q. salicina Blume was extracted using 50 % ethanol, from which ethyl acetate and aglycone fractions were prepared. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity ($FSC_{50}$) of Q. salicina Blume aglycone fraction was the highest ($8.25\;{\mu}g$/mL). The luminol-dependent chemiluminescence assay showed that reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of Q. salicina Blume aglycone fraction on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system was the most prominent at $0.039\;{\mu}g$/mL. The protective effects of extract/fractions of Q. salicina Blume against the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner ($1{\sim} 25\;{\mu}g$/mL). Especially, ${\tau}_{50}$ of aglycone fraction in $10 \;{\mu}g$/mL concentration showed the most protective effect at 259.9 min. The inhibitory effects ($IC_{50}$) on tyrosinase and elastase of Q. salicina Blume extracts were higher at aglycone fraction (respectively, $21.82 \;{\mu}g$/mL, $41.18\;{\mu}g$/mL). Active component analysis by TLC and HPLC showed quercetin, keampferol, catechin, quercitrin, isoquercitrin, hyperoside, and etc. These results indicate that Q. salicina Blume extract has strong antioxidative activity and can be used as antioxidant. Particularly, aglycone fraction of Q. salicina Blume showed superior antioxdative activity and high inhibitory effect on tyrosinase and elastase. Therefore, aglycone fraction of Q. salicina Blume could be applicable to new functional cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.157-165
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• 2010

In this study, the antioxidative effects, inhibitory effects on tyrosinase and elastase of Rhododendron brachycarpum D. Don extracts were investigated. And the moisturizing effect of cream containing R. brachycarpum D. Don extract were investigated by clinical trial. The ethyl acetate fraction of R. brachycarpum D. Don extract (1.83 ${\mu}g/mL$) showed the most prominent the free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of R. brachycarpum D. Don extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The 50 % extract fraction (0.064 ${\mu}g/mL$) showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of R. brachycarpum D. Don on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The R. brachycarpum D. Don extracts suppressed photohemolysis in a concentration dependent manner (1 ~ 10 ${\mu}g/mL$). The inhibitory effects ($IC_{50}$) of R. brachycarpum D. Don extracts on tyrosinase were determined with ethyl acetate fraction of R. brachycarpum D. Don extract (70.5 ${\mu}g/mL$) and aglycone fraction of extract (122.40 ${\mu}g/mL$). The inhibitory effects ($IC_{50}$) on elastase were determined with ethyl acetate of R. brachycarpum D. Don extract (43.50 ${\mu}g/mL$) and aglycone fraction of extract (20.73 ${\mu}g/mL$). The cream containing the ethyl acetate fraction of R. brachycarpum D. Don extracts was formulated for skin hydration effect and transepidermal water loss (TEWL). The cream containing R. brachycarpum D. Don extract was applied to the right lower arm. After 180 min, the water contents in skin were increased by 1 ~ 4 % than the placebo cream. And TEWL of parts was decreased as 7.7 $g/m^2h$ (experimental cream) and 8.9 $g/m^2h$ (placebo cream) respectively. These results indicate that extract/fractions of R. brachycarpum D. Don can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And inhibitory activity on tyrosinase of the aglycone fraction could be applicable to new functional cosmetics for whitening and anti-wrinkle products. Also the increase of skin hydration of the cream containing extract could be applicable to new functional cosmetics for antiaging.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.25-35
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• 2008

In this study, the antioxidative effects and inhibitory effects on elastase and tyrosinase of Geranium nepalense extracts were investigated. The free radical(1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}$) of extract/fractions of Geranium nepalense were in the order: 50% ethanol extract(15.0 ${\mu}g/mL$)${\mu}g/mL$). ${\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities($OSC_{50}$) of some Geranium nepalense extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescense assay. The order of ROS scavenging activities were 50% ethanol extract($OSC_{50},\;0.23{\mu}g/mL$)${\mu}g/mL$)${\mu}g/mL$). Deglycosylated flavonoid fraction showed the most prominent scavenging activity. The protective effects of extract/fractions of Geranium nepalense on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Geranium nepalense extracts suppressed photohemolysis in a concentration dependent manner, particularly deglycosylated flavonoid fraction exhibited the most prominent celluar protective effect (${\tau}_{50}$, 676.7 min at 50 ${\mu}g/mL$). The inhibitory effect of aglycone fraction on tyrosinase($IC_{50}$, 70.0 ${\mu}g/mL$) and elastase ($IC_{50}$, 19.9 ${\mu}g/mL$) was very high. Aglycone fractions obtained from the deglycosylation reaction of ethyl-acetate fraction among the Geranium nepalense extracts, showed 2 bands in TLC and 2 peaks in HPLC experiments (370 nm). Two components were identified as quercetin(composition ratio, 15.3%), kaempferol(82.8%). These results indicate that extract/fractions of Geranium nepalense can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Geranium nepalense extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.1
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• pp.1-8
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• 2013

In this work, comparative study on antioxidative activities of extracts from Glycyrrhiza uralensis (G. uralensis) produced in Korea and in China and Glycyrrhiza glabra (G. glabra) produced in Uzbekistan was conducted. Among three origins, 50% ethanol extracts (21.15 ${\mu}g/mL$), ethyl acetate fraction (29.15 ${\mu}g/mL$) and aglycone fraction (3.26 ${\mu}g/mL$) of G. uralensis from Korea showed the higher free radical (1,1-phenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) than extracts from other origins. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of extracts from three origins on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using luminol-dependent chemiluminescence assay 50% ethanol extract (1.00 ${\mu}g/mL$) and ethyl acetate fraction (0.34 ${\mu}g/mL$) of G. uralensis from China showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of G. uralensis and G. glabra extracts on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. 50% ethanol extract and aglycone fraction of G. uralensis and G. glabra extracts from three origins showed cellular protective effects in a concentration dependent manner (5 ~ 50 ${\mu}g/mL$). Aglycone fraction of G. uralensis from Korea (${\tau}_{50}$ = 847.4 min)especially showed cellular protective effects four times higher than that from China (${\tau}_{50}$ = 194.3 min). These results indicate that G. uralensis and G. glabra extracts, which have been used as whitening agent, could be applicable to functional cosmetic ingredient as a natural antioxidant. Judging from the prominent cellular protecitve effects, it is concluded that G. uralensis and G. glabra extracts can protect the skin from $^1O_2$ and various ROS induced by UV.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.4
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• pp.309-320
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• 2017

In this study, the antioxidative effects and component analysis of 50% ethanol extract, ethyl acetate fraction and aglycone fraction obtained from Annona muricata leaf were investigated. Free radical scavenging activities were performed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, total antioxidant capacities were estimated using luminol-dependent chemiluminescence assay and $^1O_2$ quenching effects were estimated. Free radical scavenging activities ($FSC_{50}$) of 50% ethanol extract, ethyl acetate fraction and aglycone fraction were 45.6, 29.8 and $18.0{\mu}g/mL$, and total antioxidant capacities ($OSC_{50}$) were 4.4, 1.1 and $2.8{\mu}g/mL$, respectively. As a result of $^1O_2$ quenching experiment, ethyl acetate and aglycone fraction showed similar activities to L-ascorbic acid used as a comparative control. The cellular protective effects of 50% ethanol extract on the $^1O_2-induced$ cellular damage of human erythrocytes were exhibited at concentration-dependent ($5-50{\mu}g/mL$). TLC and HPLC were used to analyse components in the ethyl acetate fraction and aglycone fraction of Annona muricata leaf. In ethyl acetate fraction, rutin (quercetin-3-O-rutinoside), kaempferol-3-O-neohesperidoside, nicotiflorin (kaempferol-3-O-rutinoside), p-coumaric acid were identified. In aglycone fraction, kaempferol was identified. These results suggest that the extracts of Annona muricata leaf have the applicability as antioxidant cosmeceutical ingredients.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.9-26
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• 1999

The Ulleung Basin (Tsushima Basin) in the southwestern East Sea (Japan Sea) is floored by a crust whose affinity is not known whether oceanic or thinned continental. This ambiguity resulted in unconstrained mechanisms of basin evolution. The present work attempts to define the nature of the crust of the Ulleung Basin and its tectonic evolution using seismic wide-angle reflection and refraction data recorded on ocean bottom seismometers (OBSs). Although the thickness of (10 km) of the crust is greater than typical oceanic crust, tau-p analysis of OBS data and forward modeling by 2-D ray tracing suggest that it is oceanic in character: (1) the crust consists of laterally consistent upper and lower layers that are typical of oceanic layers 2 and 3 in seismic velocity and gradient distribution and (2) layer 2C, the transition between layer 2 and layer 3 in oceanic crust, is manifested by a continuous velocity increase from 5.7 to 6.3 km/s over the thickness interval of about 1 km between the upper and lower layers. Therefore it is not likely that the Ulleung Basin was formed by the crustal extension of the southwestern Japan Arc where crustal structure is typically continental. Instead, the thickness of the crust and its velocity structure suggest that the Ulleung Basin was formed by seafloor spreading in a region of hotter than normal mantle surrounding a distant mantle plume, not directly above the core of the plume. It seems that the mantle plume was located in northeast China. This suggestion is consistent with geochemical data that indicate the influence of a mantle plume on the production of volcanic rocks in and around the Ulleung Basin. Thus we propose that the opening models of the southwestern East Sea should incorporate seafloor spreading and the influence of a mantle plume rather than the extension of the crust of the Japan Arc.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.137-155
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• 1999

Recently, Televiewer(Borehole Acoustic Scanner(Televiewer)) has come to be widely used specially for the general engineering construction design. The Televiewer tool using a focussed acoustic beam is to detect the amplitude and traveltime of each reflected acoustic signal at the wall, resulting in the amplitude- and traveltime image respectively. Fractures can be well detected, because they easily scatter the acoustic energy due to the highly narrow beam. In addition, the drilling work will rough the borehole wall so that the acoustic energy can be scattered simply due to the roughness of the wall. Thus, the amplitude level can be directed associated with the elastic properties(impedance) and the hardness of the rock as well. Meanwhile, the traveltime image provides an information about the borehole shape and can be converted to a high precision 3D caliper log(max. 288 arms). In this paper, based on the high resolution of Televiewer images, general evaluation methods are illustrated to derive very reliable rock parameters.

• Sijohaknonchong
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• v.43
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• pp.5-39
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• 2015

Shijo (Korean poetic form) is a representative literature genre of a short poem among the literary works of Korea in the late Chosen Dynasty. The format of Sijo is Normal-Shijo in the form of 3 verses, 6 sections and 12 sound, and the lyrics of one Normal-Shijo has within or without 45 words. But Saseol-sijo, a type of Sijo, there is a work that has more than 100 letters due to the number of lyrics were a lot increased. Among those Saseol-sijo there is a work with 'solemn and elegant feeling' borrowing some verses even from Chinese poem, using a lot of Chinese vocabulary, but there are a lot of works with 'salacious and explicit contents'. Literary work, Shijo, is used for lyrics of vocal music as Gagok (a genre of Korean vocal music for mixed female and male voices) and Sijochang, however, there are many cases that the same Sijo poem is used as lyrics of Gagok and Shijo. But those music that use Saseol-sijo as lyrics among Gagok, the vocal music, are mainly songs with 'solemn feeling' rather than 'salacious work'. This study looked into the reason why the Saseol-sijo with 'salacious and explicit contents' are hard to be used as lyrics in Gagok, confirming the fact that most music singing Saseol-sijo among Gagok that are being handed down till now use lyrics with 'solemn and elegant feeling'. The most important thing among those reasons seems to be irregularly increasing lyrics, and in accordance with accompaniment. Gagok accompanys a number of instruments the fixed melody recorded and delivered in score. So it's almost impossible to play unless it depends on the steadily made song melody and accompaniment melody according to the chosen lyrics in advanced. Also, appreciation of literary works is usually made privately through a private reading activity, but Gagok is conducted through public performance in an open space for many people. Especially, it would have been hard to sing a salacious and explicit song gathered together with men and women of different social status in social system and custom of the late of Chosen Dynasty. This study confirmed the fact that folksy and popular character that was praised for literary characteristic of Saseol-sijo can't be easily found from Saseol-sijo that was called Gagok.