• Applied Biological Chemistry
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• v.47 no.3
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• pp.344-350
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• 2004

This study was conducted to develop and assess the applicability of mixed-bed ion exchange resin capsules for water quality monitoring in small agricultural watershed. Recoveries of resin capsules for inorganic N and P ranged from 96 to 102%. The net activation energies and pseudo-thermodynamic parameters, such as ${\Delta}G^{o\ddag},\;{\Delta}H^{o\ddag},\;and\;{\Delta}S^{o\ddag}$ for ion adsorption by resin capsules, exhibited relatively low values, indicating the process might be governed by chemical reactions such as diffusion. However, those values increased with temperature coinciding with the theory. The reaction reached pseudo-equilibrium within 24 hours for $NH_4-N\;and\;NO_3-N$, and only 8 hours for $PO_4-P$, respectively. The selectivity of resin capsules were in the order of $NO_3\;^-\;>\;NH_4\;^+\;>\;PO_4\;^{3-}$, coinciding with that of encapsulated Amberlite IRN-150 resin. At the initial state of equilibrium, the resin adsorption quantity was linearly proportional to the mass of ions in the streams, but the rate of movement leveled off, following Langmuir-type sorption isotherm. The overall results demonstrated that the resin capsule system was suitable for water quality monitoring in small agricultural watershed, judging from the reaction mechanism(s) of the resin capsule and the significance of model in field calibration.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1078-1086
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• 1996

The peroxo-polytungstic acid was formed by the direct reaction of tungsten powder with the hydrogen peroxide solution. Peroxo-polytungstic powder were prepared by rotary evaporator using the fabricated on to ITO coated glass as substrate by dip-coating method using $2g/10mL(W-IPA/H_2O)$ sol solution. A substrate was dipped into the sol solution and after a meniscus had settled, the substrate was withdrawn at a constant rate of the 3mm/sec. Thicker layer could be built up by repeated dipping/post-treatment 15 times cycles. The layers dried at the temperature of $65{\sim}70^{\circ}C$ during the withdrawn process, and then tungsten oxides thin film was formed by final heating treatment at the temperature of $230{\sim}240^{\circ}C$ for 30min. A linear rotation between the thickness of thin film and the number of dipping/post-treatment cycles for tungsten oxides thin films made by dip-coating was found. The thickness of thin film had $60{\AA}$ after one dipping. From the patterns of XRD, the structure of tungsten oxides thin film identified as amorphous one and from the photographs of SEM, the defects and the moderate cracks were observed on the tungsten oxides thin film, but the homogeneous surface of thin films were mostly appeared. The electrochemical characteristic of the $ITO/WO_3$ thin film electrode were confirmed by the cyclic voltammetry and the cathodic Tafel polaization method. The coloring bleaching processes were clearly repeated up to several hundreds cycles by multiple cyclic voltammetry, but the dissolved phenomenon of thin film revealed in $H_2SO_4$ solution was observed due to the decrease of the current densities. The diffusion coefficient was calculated from irreversible Randles-Sevick equation from the data obtained by the cyclic voltammetry with various scan rates.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.163-178
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• 2014

Following research proposes "Virtualization of Smart Cards (ViSCa)" which is a security system that aims to provide a multi-device platform for the deployment of services that require a strong security protocol, both for the access & authentication and execution of its applications and focuses on analyzing Virtualization of Smart Cards (ViSCa) platform-based mobile payment service by comparing with other similar cases. At the present day, the appearance of new ICT, the diffusion of new user devices (such as smartphones, tablet PC, and so on) and the growth of internet penetration rate are creating many world-shaking services yet in the most of these applications' private information has to be shared, which means that security breaches and illegal access to that information are real threats that have to be solved. Also mobile payment service is, one of the innovative services, has same issues which are real threats for users because mobile payment service sometimes requires user identification, an authentication procedure and confidential data sharing. Thus, an extra layer of security is needed in their communication and execution protocols. The Virtualization of Smart Cards (ViSCa), concept is a holistic approach and centralized management for a security system that pursues to provide a ubiquitous multi-device platform for the arrangement of mobile payment services that demand a powerful security protocol, both for the access & authentication and execution of its applications. In this sense, Virtualization of Smart Cards (ViSCa) offers full interoperability and full access from any user device without any loss of security. The concept prevents possible attacks by third parties, guaranteeing the confidentiality of personal data, bank accounts or private financial information. The Virtualization of Smart Cards (ViSCa) concept is split in two different phases: the execution of the user authentication protocol on the user device and the cloud architecture that executes the secure application. Thus, the secure service access is guaranteed at anytime, anywhere and through any device supporting previously required security mechanisms. The security level is improved by using virtualization technology in the cloud. This virtualization technology is used terminal virtualization to virtualize smart card hardware and thrive to manage virtualized smart cards as a whole, through mobile cloud technology in Virtualization of Smart Cards (ViSCa) platform-based mobile payment service. This entire process is referred to as Smart Card as a Service (SCaaS). Virtualization of Smart Cards (ViSCa) platform-based mobile payment service virtualizes smart card, which is used as payment mean, and loads it in to the mobile cloud. Authentication takes place through application and helps log on to mobile cloud and chooses one of virtualized smart card as a payment method. To decide the scope of the research, which is comparing Virtualization of Smart Cards (ViSCa) platform-based mobile payment service with other similar cases, we categorized the prior researches' mobile payment service groups into distinct feature and service type. Both groups store credit card's data in the mobile device and settle the payment process at the offline market. By the location where the electronic financial transaction information (data) is stored, the groups can be categorized into two main service types. First is "App Method" which loads the data in the server connected to the application. Second "Mobile Card Method" stores its data in the Integrated Circuit (IC) chip, which holds financial transaction data, which is inbuilt in the mobile device secure element (SE). Through prior researches on accept factors of mobile payment service and its market environment, we came up with six key factors of comparative analysis which are economic, generality, security, convenience(ease of use), applicability and efficiency. Within the chosen group, we compared and analyzed the selected cases and Virtualization of Smart Cards (ViSCa) platform-based mobile payment service.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.203-215
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• 2017

Recently, interest in Pedestrian Navigation Service (PNS) is being increased due to the diffusion of smart phone and the improvement of location determination technology and it is efficient to use landmarks in route guidance for pedestrians due to the characteristics of pedestrians' movement and success rate of path finding. Accordingly, researches on extracting landmarks have been progressed. However, preceding researches have a limit that they only considered the difference between buildings and did not consider visual attention of maps in display of PNS. This study improves this problem by defining building attributes as local variable and global variable. Local variables reflect the saliency of buildings by representing the difference between buildings and global variables reflects the visual attention by representing the inherent characteristics of buildings. Also, this study considers the connectivity of network and solves the overlapping problem of landmark candidate groups by network voronoi diagram. To extract landmarks, we defined building attribute data based on preceding researches. Next, we selected a choice point for pedestrians in pedestrian network data, and determined landmark candidate groups at each choice point. Building attribute data were calculated in the extracted landmark candidate groups and finally landmarks were extracted by principal component analysis. We applied the proposed method to a part of Gwanak-gu, Seoul and this study evaluated the extracted landmarks by making a comparison with labels and landmarks used by portal sites such as the NAVER and the DAUM. In conclusion, 132 landmarks (60.3%) among 219 landmarks of the NAVER and the DAUM were extracted by the proposed method and we confirmed that 228 landmarks which there are not labels or landmarks in the NAVER and the DAUM were helpful to determine a change of direction in path finding of local level.

• Journal of the Korean Geographical Society
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• v.29 no.2
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• pp.137-165
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• 1994

Structural adjustment of industry (or industrial restructuring) seems to be inherent in the process of capitalist economic development, which tends to be proceeded with shifts from one stage to another in order to overcome structural crises generated in each stage. The structural adjustment of industry is necessarily accompanied with regional restructuring, since it is not only projected on spece, but also mediated by space. Such a restructuring necessitates industrial and uneven regional devlopment through which capital can seek excessive profits over the rate of socio-spatial average. The industrial restructuring and uneven regional development in the 1980s in Korea can be seen as a process in which capital attempted with a strong support of the govenment to overcome the crises in the end of 1970s and hence to go on rapid economic growth. In this process, capital, especially monopoly capital concentrated into few conglomerates, pursued both extensive expansion and intensive development of industry simultaneously. In results, the Korean economy could eliminate some of peripheral characters and maturate the Fordist accumulation system. The extensive expansion of the Korean industry in the 1980s was stimulated mainly through the enlargement and adjustment of investment for equipment facilities which was planned to exclude or rationalize traditional light industries on some places, and to continue rapid growth of key heavy-chemical industries, especially of fabricated metal industry, on other places. In this process, keeping mainly the existing developmental axis which polarized the Seoul Metroplitan region and the Southeast region in Korea, the enhancing spatial mobiiity of capital and the further differentiating division of labour enforced a tendency of concentration of all types of industry in the Seoul Metropolitan region, and at the same time provoked the diffusion of some industries over Jeolla and Chungchong regions in a considerable extent. The intensive development of industriai structure in the 1980s was pursued through the strategic encouragement of subcontracting small firms mainly which produced assembling components, the technical enhancement and factory (semi-) automation, and the enrichment of service industries for estate management, finance, distribution and retailing which supported and complemented the production of goods. In this process, enabling capital to extend and elaborate its domination over space through the reorganization of regulating systems, the Fordist division of labour generated a socio-spatial hierarchy in the nation-wide scale that characterized: the Seoul Metropolitan region as an overmaturated (or overarching) Fordist region performing the conceptive functions of management, research and development, in which all types of industry (including service industries) tended to be reconcentrated; Kyungsang region as a maturated Fordist region with excutive branches of large conglomerates and with subcontracting firms around them which produced standardized products through the automized production processes in secialized Fordist industries or rationalized traditional industries; and Jeolla and Chungchong regions as newly devloping Fordist regions with newly migrated branches and some subcontracting small firms-in relatively older Fordist industries or partly rationalized traditional industries. From these analyses, it can be argued that the structural adjustment of the Korean industry in the 1980s, which had carried out both through the extensive expansion and the intensive deveiopment, strengthened further uneven regional development process, even though it appears to have reduced apparently the economic and regional disparity by balancing numerically large and small firms and by extending the Fordist industrial space nation-wideiy. And it seems more persuasive to see that the Korean industrial structure in the 1980s maturated the Fordist system of accumulation, but not yet transformed towards the post-Fordist (or the so-called flexible) accumulation system, even though the Korean economy in the 1990s seems to be under a pressure of restructuring towards the latter system.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.359-369
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• 2018

Harmful algal blooms (HABs) are a serious problem for public health and fisheries industries, thus there exists a need to investigate the possible ways for effective control of HABs. In the present study, we investigated the algicidal effects of a newly developed GreenTD against the HABs (Chattonella marina, Heterosigma akashiwo, Cochlodinium polykriokides, and Heterocapsa circularisquama) and non-HABs (Chaetoceros simplex, Skeletonema sp. and Tetraselmis sp.), which is focused on the different population density and concentration gradients of algicidal substances. The time series viability of target alga was assessed based on the activity of Chl. a photosynthetic efficiency in terms of $F_v/F_m$, and in vivo fluorescence (FSU). Effective control of Raphidophyta, C. marina and H. akashiwo was achieved at a GreenTD concentration of $0.5{\mu}gL^{-1}$ and $0.2{\mu}gL^{-1}$, respectively, and regrowth of both the species was not observed even after 14 days. The inhibitory ratio of the dinoflagellate, C. polykriokides was more than 80% at $0.2{\mu}gL^{-1}$ of GreenTD. H. circularisquama was constantly affected in the presence of $0.2{\mu}gL^{-1}$ of GreenTD in the high- and low-population density experimental groups. On the other hand, diatoms, C. simplex, and Skeletonema sp. were not significantly affected even in the presence of $0.2{\mu}gL^{-1}$ of GreenTD and exhibited re-growth activity with the passage of incubation time. In particular, green alga Tetraselmis sp. remained unaffected even in the presence of the highest concentration of GreenTD ($1.0{\mu}gL^{-1}$), implying that non-HABs were not greatly influenced by the algicidal substances. As a result, the algicidal activity of GreenTD on the harmful and nonharmful algae was as follows: raphidophyte>dinoflagellates>diatoms>green alga. Consequently, our results indicate that inoculation of GreenTD substances into natural blooms at a threshold concentration ($0.2{\mu}gL^{-1}$) can maximize the algicidal activity against HABs species. If we consider the dilution and diffusion rate in the field application, it is hypothesized that GreenTD will demonstrate economic efficiency, thus leading to effective control against the target HABs in the closed bay.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.766-778
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• 2019

In this study, Poria cocos bark were extracted by supercritical process, and anti-inflammatory, whitening, and antioxidant effects were measured in comparison with ethanol extract. Also, An effective percutaneous permeation method using a selected formulation of the extract and a drug delivery peptide was proposed. Pachymic acid, known as the anti-cancer and anti-inflammatory compound of the ventricle, is an indicator component and the HPLC analysis shows that the supercritical extract of the pericardium is more than twice that of the Poria cocos bark extract. In order to confirm antioxidative effect of Bombyx mori, DPPH scavenging ability and ABTS scavenging ability test showed that the ethanol extract of Poria cocos Back had lower concentration than the supercritical extract of Poria cocos back. However, RAW 264.7 Measurements of Nitric oxide (NO) production in cells showed lower NO production at the same concentration than the Poria cocos back ethanol extract. In addition, after 72 hours of processing of $20{\mu}g/mL$ of the Poria cocos back extract in B16 melanoma cells, both the intracellular and extracellular melanin extract were effective and the supercritical extract was lower melanin content. No toxicity was observed at the concentration of $800{\mu}g/mL$ in RAW 264.7 cells used in NO production experiments. However, in B16 melanoma cells, even at $50{\mu}g/mL$, both Poria cocos back ethanol extract and supercritical extract showed a survival rate of less than 60%. The liposome formulation and drug delivery peptides were shown to be useful for percutaneous permeation of Supercritical Extract of Poria cocos back using a liposome formulation and a drug delivery peptide. it is expected that there will be great potential for development as a variety of cosmetic materials for Poria cocos back.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.16-19
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• 2019

A thinner film has superior electrical properties and a better amorphous structure. Amorphous structures can be effective in improving conductivity through a depletion effect. Research is needed on the Schottky contact, where potential barriers are formed, as a way to identify these characteristics. $SiO_2/SnO_2$ thin films were prepared to examine the amorphous structure and Schottky contact, $SiO_2$ thin films were prepared using Ar = 20 sccm. $SnO_2$ thin films were deposited using mixed gas with a flow rate of argon and oxygen at 20 sccm, and $SnO_2$ thin films were added by magnetron sputtering and treated at $100^{\circ}C$ and $150^{\circ}C$. To identify the conditions under which the amorphous structure was constructed, the XRD patterns were investigated and C-V and I-V measurements were taken to make Al electrodes and perform electrical analysis. The depletion layer was formed by the recombination of electrons and holes through the heat treatment process. $SiO_2/SnO_2$ thin films confirmed that the pores were well formed when heat treated at $100^{\circ}C$ and an electric current was applied over the micro area. An amorphous $SiO_2/SnO_2$ thin film with heat treatment at $100^{\circ}C$ showed no reflection at $33^{\circ}\;2{\theta}$ in the XRD pattern, and a reflection at $44^{\circ}2\;{\theta}$. The macroscopic view (-30 V

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.8-17
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• 2004

Antifungal, antibacterial, and antioxidative activities of ethanol extracts from 65 families 263 species were investigated to select tree species for the utilization of natural fungicide or preservative resources. The antifungal activities of extracts from wood, leaf and bark were measured as hyphal growth inhibition rate using four plant pathogenic and five wood rotting fungi. High inhibitory effect on the fungi growth was found in five species of Pinaceae (Pinus koraiensis, P. rigida, P. densiflora, P. banksiana. Cedrus deodara), three species of Cupressaceae (Juniperus rigida, J. chinensis, Chamaecyparis obtusa) and three species of Leguminosae (Albizzia julibrisssin, Sophora japonica, Maackia amurensis), respectively. Antibacterial activities of ethanol extracts were determined by means of disc-agar plate diffusion method using three gram-positive and five gram-negative bacteria. The ethanol extracts, which showed prominent effect on the suppression of bacteria growth, were six species of Betulaceae (Carpinus tschonoskii, C. coreana, C. laxiflora, Alnus hirsuta, A. firma, Betula schmidtii), five species of Fagaceae (Castanopsis cuspidata var. sieboldii, Quercus serrata, Q. mongolica, Q aliena, C crenata), four species of Euphorbiaceae (Aleurites fordii, Sapium sebiferum, S japonicum Mallotus japonicus) and three species of Elaeagnaceae (Elaeagnus umbellata, Elaeagnus glanbra, Elaeagnus macrophylla). According to these results, the extracts from Zelkova serrata, Pinus densiflora, Maackia amurensis, Chamaecyparis obtusa and Juniperus chinensis could be available for natural fungicide or food preservatives, because ethanol extracts from these species indicated excellent antifungal and antibacterial activities. In order to test antioxidative activities of ethanol extracts, free radical scavenging method was adopted with 1,1-diphenyl-2-picrylhydrohydrazyl (DPPH). Free radical scavenging activity was proved very high in the extracts of eight species of Rosaceae (Eriobotrya japonica, Prunus takesimensis, P yedoensis, P padus, P armeniaca var. ansu, Chaenomeles sinensis, Stephanandra incisa, Rosa multiflora) and five species of Ericaceae (Rhododenron mucronulatum, R. scblippenbacbii, R. yedoense var. poukhanense, Vaccinium bracteatum, V oldbami), resvectively. It turned out from this study that only six species among 48 species of Rosaceae showed less than 80% free radical scavenging activity. As a consequences, it could be deduced that the components effective on antioxidative activity commonly exist in Rosaceae plant family.