• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.296-301
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• 2023

Solid oxide fuel cell has received more attention recently due to the fuel flexibility via internal reforming. Commonly used Ni/YSZ anode, however, can be easily deactivated by carbon coking in hydrocarbon fuels. The carbon deposition problem can minimize by developing alternative perovskite anode. This study is focused on improving conductivity and catalytic activity of the perovskite anode by introducing rGO (reduced graphene oxide). Sr_0.92Y_0.08TiO₃(SYT) anode with perovskite structure was synthesized with 1wt% of rGO. The presence of rGO during anode fabricating process and cell operation is confirmed through XPS and Raman analysis. The maximum power density of rGO/SYT anode improved to 3 times in H₂ and 6 times in CH₄ comparing to that of SYT anode due to the high electrical conductivity and good catalytic activity for CH₄.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.781-788
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• 2014

Polyaniline modified graphene oxide (PANI/GO) composites were synthesized by dilute polymerization technique and were characterized by Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). The characterization results indicated that polyaniline molecules were successfully grafted on GO surfaces. The application of PANI/GO composites to the adsorption of heavy metals from aqueous solutions was investigated under ambient conditions. The maximum adsorption capacities of Co(II), Ni(II), Pb(II) and U(VI) ions on PANI/GO composites calculated from Langmuir models are 22.28, 25.67, 65.40 and 1552.31 mg/g, respectively. The excellent adsorption capacity suggests that PANI/GO composites can be applied as a promising adsorbent in heavy metal pollution cleanup in environmental pollution management.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.814-822
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• 2018

This paper proposes a guidance law for missiles with control time constraint. Because the proposed guidance law is based on a time-to-go polynomial, it has a generalized form. Also, acceleration of the proposed law converges to zero at the end of the control time, which reduces the sensitivity to the time-to-go estimation error and can increase the flight stability when the separation of the missile appears. A prediction method of the time-to-go is proposed for implementing the proposed law, and the possibility of application to the midcourse and terminal guidance phases is dealt with for exoatmospheric interception. The characteristics and performance of the proposed law are analyzed throughout various simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.597-604
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• 1994

In this paper, the "Stop-and-GO" algorithm is applied to the PRS(Partial Response Signal) type signaling. Stop-and-GO blind equalizer has a property of stopping the adaptation of its tab coefficients by means of a simples flag telling the equalizer whether the current output error with respect to decided symbol is sufficiently reliable to be used. PRS has the rule os level transition, which makes it possible that the level of currently received symbol is in the adjacent levels of the previously received symbol. New nonlinear estimators for PRS, based on the rule of level transition, is proposed. The computer simulation results show the improvement in performance achievable with proposed nonlinear estimators.stimators.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.27
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• pp.69-95
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• 2005

East Asia has played an important role in the economic and social development in the Asian pacific region and in the global arena. In the region the impact of companies centralizing their logistics activities around a few distribution centers has already led some leading ports such as Singapore, Hong Kong to transform and expand their functions and business activities to provide port users with value added logistics services. Other ports in the region also have an important part to play in the total logistics Chain. In these environments, the maritime activities of Jang BoGo, who was the maritime king of the commercial maritime empire in East Asia in the 9th century, give many implications to the international logistics network strategy that Korea has to take in order to become a power of International Logistics. Though the trading and economic environments at that time may be quite different from today, the super-national maritime management pattern that Jang Bo-go, founder of the Northeast Asian maritime trading kingdom devised, gives us many implications in the global trading and economic environments, in the respects of overseas direct investment and international logistics. Accordingly, the paper aims to examine the establishment of hub port in Northeast Asia, modelled after the maritime network management strategy of Jang BoGo.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1979-1984
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• 2014

We have developed an efficient method to generate highly active Pd and PdO nanoparticles (NPs) dispersed on graphene and graphene oxide (GO) by an impregnation method combined with thermal treatments in $H_2$ and $O_2$ gas flows, respectively. The Pd NPs supported on graphene (Pd/G) and the PdO NPs supported on GO (PdO/GO) demonstrated excellent carbon-carbon cross-coupling reactions under a solvent-free, environmentally-friendly condition. The morphological and chemical structures of PdO/GO and Pd/G were fully characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). We found that the remarkable reactivity of the Pd/G and PdO/GO catalysts toward the cross-coupling reaction is attributed to the high degree of dispersion of the Pd and PdO NPs while the oxidative states of Pd and the oxygen functionalities of graphene oxide are not critical for their catalytic performance.

• The Journal of Internal Korean Medicine
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• v.21 no.1
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• pp.108-115
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• 2000

Objective : To investigate the hepatoprotective effects of Gami-oryungsan on the liver damage induced by bromobenzene. Method : The development of fibrosis and acute liver injury was examined by the chemical analysis of AST, AL T, ${\gamma}$-GTP . and epoxide hydrolase glutathione S-transferase glutathione peroxidase enzyme activity, lipidoperoxide levels, glutathione levels were measured and oberved. Results : The increasing levels of lipidoperoxide was decreased proportionally according to dose of extract GO. Epoxide hydrolase glutathioneS-transferase glutathione peroxidase enzyme activity highly increased in GO pre-acupunctured group compared with the group treated with only bromobenzene. The increase of serum AST, AL T, ${\gamma}$-GTP enzyme activity of mice by bromobenzene was inhibited by the administration of GO. Lipidoperoxide levels in rat's liver decreased compared to the case of bromobenzene-treated group. The levels of Glutathione decreased by bromo benzene were increased highly in GO pre-acupunctured group. Conclusion : These results suggest that GO extract recovers the damage of liver due to bromobenzene intoxication by decreasing the lipid peroxidation AST AL T ${\gamma}$-GTP enzyme activity and increasing epoxide hydrolase glutathioneS-transferase glutathione peroxidase enzyme activity, glutathione levels.

• Journal of Korea Game Society
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• v.14 no.6
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• pp.39-48
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• 2014

Go is an extremely complex strategy board game despite its simple rules. By using MCTS, the computer Go programs with handicap game have been defeated human Go professionals. MCTS is based on the winning rate estimated by MC simulation rather than strategy concept. Meanwhile Genetic algorithm equipped with an adequate fitness function can find out the best solutions in the game. The game of Tic-Tac-Toe, also known as Naughts and Crosses, is one of the most popular games. We tried to find out the best strategy in the game of Tic-Tac-Toe. The experimental result showed that Genetic algorithm enables to find efficient strategies and can be applied to other board games such as Go and chess.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1364-1373
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• 1994

In this thesis, an algorithm for fast convergence to the steady state and for achieving an improved MSE in blind adaptive equalizers is proposed. The conventional radius-directed algorithm can be transformed into an algorithm that provides effective blind convergence in the aspect of the MSE as the convergence speed. This can be achieved through altering the stop and go algorithm. The performance of the new algorithm is analyzed and compared with the two conventional algorithms, such as the CMA and the stop and go algorithm. The experimental results show the superiority of the new algorithm.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.499-502
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• 2003

Neurotoxicity of reactive oxygen species(ROS) and neuroprotective effect of Aconiti Radix(AR) against ROS-induced cytotoxicity were determined on cultured mouse cerebral neurons by MTT assay after cerebral neurons were cultured for 5 hours in various concentrations of GO. GO was toxic in a dose-dependent manner on cultured cerebral neurons after cerebral neurons were incubated for 5 hours in media containing 5～40mU/ml GO. While, cultures were pretreated with 180 μg/ml AR for 2 hours increased remarkably cell viability. From these results, it is suggested that GO has toxic effect on cultured mouse cerebral neurons by the decrease of cell viability. And also, herb extract such as AKR is very effective in the protection pf neurotoxicity induced by GO.