• 대한화장품학회지
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• 제23권3호
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• pp.101-107
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• 1997

Phellinus linteus was artificially cultivated in kangwon province in Korea. The air-dried phellinus linteus was frozen in liquid nitrogen tank and powdered in jar. 10g of the powder was extracted with each 200g of ethanol, methanol, distilled water and 1,3-butylene glycol/distilled water 4 hours under refluxing and then the liquidextract was concentrated under reduced pressure. As a result of analysis by high performance liquid chromatography and thin layer chromarography, many kinds of sugar and flavonoids were detected. Also we knew that phellinus linteus' extract had a strong UV-ray absorption. In the efficacy test for applying to cosmetics, free radical scavenging effect was confirmed. As a result, 2% of sample was the most potent inhibitory effect and the free radical savenging activity, was 0.31%. This is more effective than any other meterial. In the test of antioxidative activity against lipid autoxidation, phellinus linteus' extract had a good effect by 46% while vitamine E was 42.3%. The immunological activity of phellinus linteus was showed through the activation of macrophage cell. Actually, phellinus linteus activated macrophage function of 1.1-1.8 times including nitrite production compared to control. The whitening effect of phellinus linteus was showed through the inhibition of tyrosinase activity, melanin biosynthesis of S. bikiniensis and B-16 melanoma cells. Phellinus linteus' extract was showed strong mushroom tyrosinase inhibitory activity with IC50 value of 0.5% and inhibited melanin biosynthesis with 28mm inhibition zone at 0.005%/paper disc in S. bikinniensis, a bacterium used as an indicator organism in this work. Also it inhibited melanin biosynthesis in B-16 melanoma cells with a minimum inhibitory concentration of 0.134%.

• 생약학회지
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• 제35권4호통권139호
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• pp.293-299
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• 2004

The current investigation was carried out to find out the anticancer activity of the methanol extract from Buplerum falcatum against cancered ICR mouse and cancer cell lines such as J774A.1 and L1210 cells. Extract of Buplerum falcatum displayed the considerable augmentation(134%) of the survival of ICR mouse bearing Sarcoma 180 cancer. In addition, the cytotoxic effects of methanol extract of Buplerum falcatum against J774A.1 cells and L1210 cells were found to show $IC_{50}$ values of $57.3\;{\mu}g/ml$ and $54.6\;{\mu}g/ml$, respectively. In contrast to such cytotoxicity against cancer cells, the extract exerted only meagre toxicity against normal lymphocytes. The increased generation of $O_2^-$ and the considerably increased activities of super-oxide dismutase(SOD) and glutathione peroxidase(GPx) of both J774A.1 cells and L1210 cells in the presence of Buplerum falcatum extract implied that the observed cytotoxicities may have resulted from the detrimental effect of reactive oxygen species(ROS) evoked by Buplerum falcatum extract on the cancer cells.

• Earthquakes and Structures
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• 제25권2호
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• pp.125-134
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• 2023

In the present work, a new global damage index is proposed for the seismic performance and failure analysis of concrete gravity dams. Unlike the existing indices of concrete structures, this index doesn't need scaling with an ultimate or an upper value. For this purpose, the Beni-Haroun dam in north-eastern Algeria, is considered as a case study, for which an average seismic capacity curve is first evaluated by performing several incremental dynamic analyses. The seismic performance point of the dam is then determined using the N2 method, considering multiple modes and taking into account the stiffness degradation. The seismic demand is obtained from the design spectrum of the Algerian seismic regulations. A series of recorded and artificial accelerograms are used as dynamic loads to evaluate the nonlinear responses of the dam. The nonlinear behaviour of the concrete mass is modelled by using continuum damage mechanics, where material damage is represented by a scalar field damage variable. This modelling, which is suitable for cyclic loading, uses only a single damage parameter to describe the stiffness degradation of the concrete. The hydrodynamic and the sediment pressures are included in the analyses. The obtained results show that the proposed damage index faithfully describes the successive brittle failures of the dam which increase with increasing applied ground accelerations. It is found that minor damage can occur for ground accelerations less than 0.3 g, and complete failure can be caused by accelerations greater than 0.45 g.

• Journal of Microbiology and Biotechnology
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• 제19권2호
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• pp.172-177
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• 2009

A gene(lsd1) encoding dextranase from Lipomyces starkeyi KSM22 has been previously cloned, sequenced, and expressed in Saccharomyces cerevisiae. The gene consisting of 1,824 base pairs and encoding a protein of 608 amino acids was then cloned into and secretively expressed in Pichia pastoris under the control of the AOX1 promoter. The dextranase productivity of the P. pastoris transformant(pPIC9K-LSD1, 134,000 U/I) was approximately 4.2-fold higher than that of the S. cerevisiae transformant(pYLSD1, 32,000 U/I) cultured in an 8-1 fermentor. Over 0.63 g/l of active dextranase was secreted into the medium after methanol induction. The dextranase of the P. pastoris transformant, as analyzed by SDS-PAGE and Western blotting, showed only one homogeneous band. This dextranase of the P. pastoris transformant showed a broad band near 73 kDa. Rabbit monoclonal antibodies against a synthetic LSD1 peptide mix also recognized approximately 73 kDa.

• Journal of Information Technology Applications and Management
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• 제16권4호
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• pp.109-134
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• 2009

Compared to research on the success of IT projects in general, research on the management of conflict in IT teams and its impact on project success is insufficient. This research performed a comparative study to analyze the nature and evolving phenomenon of conflicts in IT project teams. This study aimed at; First, Why a conflict is created within and around an IT project team. Second, What is the phenomenon of conflict evolution, diffusion, and/or resolution? Third, How the differences in conflict management style affects the IT project performance? Three propositions were drawn from the analysis of two intensive analysis of conflict cases and their comparison. Proposition 1 : Both 'the method of pointing out a problem' and 'the pointed-out contents' can be the trigger of conflicts around an IT project. Proposition 2 : While the focus of attention of one party is 'the method of pointing out a problem', if the other's and focus of attention of one party is 'the pointed-out contents', that is, if the focus of attention mismatch, the conflict can be amplified. Proposition 3 : According to the temporal nature of the relationship, e.g., short-term versus long-term, the way people approach and deal with the conflict differs.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.288-293
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• 2001

A critical heat flux (CHF) prediction method using an artificial neural network (ANN) was evaluated for application to the high-heat-flux (HHF) subcooled flow boiling. The developed ANN predictions were compared with the experimental database consisting of a total of 3069 CHF data points. Also, the prediction performance by the ANN was compared with those by mechanistic models and a look up table technique. The parameter ranges of the experimental data are: $0.33{\leq}D{\leq}37.5mm$, $0.002{\leq}L{\leq}4m$, $0.37{\leq}G{\leq}134Mg/m^2s$, $0.1{\leq}P{\leq}20MPa$, $50\leq{\Delta}h_{sub,in}\leq1660kJ/kg$, and $1.1{\leq}q_{CHF}\leq276MW/m^2$. $276MW/m^2$. It was found that 91.5% of the total data points were predicted within $a{\pm}20%$ error band, which showed the best prediction performance among the existing CHF prediction methods considered.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2004-2008
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• 2014

This paper reports the facile synthesis methods of zinc oxide (ZnO) nanoparticles, Z1-Z10, using diethylene glycol (DEG) and polyethylene glycol (PEG400). The particle size and morphology were correlated with the PEG concentration and reaction time. With 0.75 mL of PEG400 in 150 mL of DEG and a 20 h reaction time, the ZnO nanoparticles began to disperse from a collective spherical grain shape. The ZnO nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and a $N_2$ adsorption-desorption studies. The Brunauer-Emmett-Teller (BET) surface areas of Z4, Z5 and Z10 were 157.083, 141.559 and 233.249 $m^2/g$, respectively. The observed pore diameters of Z4, Z5 and Z10 were 63.4, 42.0 and 134.0 ${\AA}$, respectively. The pore volumes of Z4, Z5 and Z10 were 0.249, 0.148 and 0.781 $cm^3/g$, respectively. The photocatalytic activity of the synthesized ZnO nanoparticles was evaluated by methylene blue (MB) degradation, and the activity showed a good correlation with the $N_2$ adsorption-desorption data.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1999년도 학술발표대회 논문집 제18권 2호
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• pp.131-134
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• 1999

This paper considers the acoustical characteristics of the mechanical valve employed in the Korean type Artificial Heart. $Bj\"{o}rk-Shiley$ tilting disc valve was chosen for the study and acoustic measurements were performed for the artificial heart operated in a mock circulation system as well as implanted to an animal as a Bi Ventricular Assist Device (BVAD). In the mock system, three different conditions of the valve were examined which were normal, damaged (torn off), pseudothrombus attached. Microphone measurements for the BVAD were carried out at a regular time interval for 5 days after the implantation operation. Of the recorded acoustic emissions from the artificial heart, click sounds mainly originated from the valves were further analyzed using Multiple Signal Classification (MUSIC) for estimating their spectral properties. It was shown that the spectral peaks below 4 kHz and the optimal order number for MUSIC, equivalent to the number of the spectral component, might be the key parameters which were highly correlated to the physiological states of the valve like the mechanical damage of the valve or the formation of thrombus on the valves.

• 한국안전학회지
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• 제31권6호
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• pp.129-134
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• 2016

Standard design of APR+(advanced power reactor plus) was certified at 2014 by Korea regulatory body. Based on the experience gained from OPR1000 and APR1400, the APR1400 was being developed as a 1,500MWe class reactor using Korean technologies for design code, reactor coolant pump, and man-machine interface system. APR+ has been basically designed to have the seismic design basis of safe shutdown earthquake (SSE) 0.3g, a 4-train safety concept based on N+2 design philosophy, and a passive auxiliary feedwater system (PAFS). Also, safety issues on the Fukushima-type accidents have been extensively reviewed and applied to enhance APR+ safety. APR+ provides higher reliability and safety against tsunami and earthquake. The purpose of this paper is to implement probabilistic safety assessment considering these design features and to analyze sensitivity of core damage frequency for large loss of coolant accident of APR+.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.121-134
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• 1994

Shock tube investigation of ethylene oxide-$0_{2}-N_{2}$ mixture have been performed to reveal detonation characteristics of the mixture in terms of detonation pressure and speed. Theoretical calculation of thermodynamic parameters at the Chapmann-Jouguet detonation of the mixture has been also performed. A comparision of the observed results with the calculated ones can lead us to predict the detonation parameters of ethylene oxide in an artificial air. In addition, we have observed ignition delay times of ethylene oxide mixtures. The best fit of the observed delay times to Arrhenius gas kinetic relation gives : ${\tau}=10^{-144}{e{xp}}(E_a/RT)[C_{2}H_{4}O]^{-4.8}[O_{2}]^{-12.4}[N_{2}]^{-14.1}$ $E_a=3.67kcal/mole$ The observed activation energy is markedly reduced, compared with the case of ethylene oxide diluted in Ar. It could be due to the factor that $N_2$ play a role as detonation promoter yielding very reactive NOx radicals.