• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.1051-1054
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• 2008

The entropy production in a non-equilibrium state based on the reversible Oregonator model of the Belousov-Zhabotinskii (BZ) reaction system has been studied. The reaction affinity and the reaction rate for the individual steps have been calculated by varying the concentrations of key variables in the system. The result shows a linear relationship between the reaction affinity and the reaction rate in the given concentration range. However, the overall entropy calculated on the basic assumption that the entropy in a reaction system corresponds to the summation of a product of reaction affinity and reaction rate of individual steps shows a nonlinearity of the reaction system. The results well agrees with the fact that the entropy production is not linear or complicated function in a non-linear reaction system.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.244-251
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• 1993

A novel system has been developed to produce ${\delta}-aminolevulinic$ acid (ALA) using the intact cells of late logarithmic phase of Rhodocyclus gelatinosus KUP-74. The system was shown optimum yield of extracellular ALA under a condition of anaerobic light irradiation (4 Klux) at $30^{\circ}C$ with no variation in cell mass. The rate of extracellular ALA formation was stimulated by low doses of either $C_4\;or\;C_5$ ALA biosynthetic precursors, where 5 mM ($C_4) and 3 mM ($C_5) of each precursors were appeared to generate the maximum rates of 3.3 and 4.0 nmoles of ALA per 0.35 mg cells per hr, respectively. Half-life of the system was 10 hr in a sense of an ability of portage transport of L-glutamate, and sequential dose of this compound was resulted in promising recovery of the ALA.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.26-31
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• 2008

A precision four-degree-of-freedom measurement system has been developed for simultaneous measurement of four motion errors of a linear stage, which include straightness and angular errors, The system employs a retro-reflector to detect the straightness errors and a plane mirror to detect the angular errors. A common-path compensation method for laser beam drift is put forward, and the experimental results show that the influences of beam drift on four motion errors can be reduced simultaneously. In comparison with the API 5D laser measuring system, the accuracy for straightness measurement is about ${\pm}1.5{\mu}m$ within the measuring range of ${\pm}650{\mu}m$, and the accuracy for pitch and yaw measurements is about ${\pm}1.5$ arc-seconds within the range of ${\pm}600$ arc-seconds.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.98-104
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• 2011

The introduction of a diesel engine into the passenger car and light duty applications in the United States involves significant technical challenges for the automotive makers. This paper describes the SCR System optimization procedure for such a diesel engine application to meet Tier2 Bin5 emission regulation. A urea SCR system, a representative $NO_x$ reduction after-treatment technique, is applied to a 3.0 liter diesel engine. To achieve the maximum $NO_x$ reduction performance, the exhaust system layout was optimized using series of the computational fluid dynamics and the urea distribution uniformity test. Furthermore a comprehensive simulation model for the key factors influencing $NO_x$ reduction performance was developed and embedded in the Simulink/Matlab environment. This model was then applied to the urea SCR system and played a key role to shorten the time needed for SCR control parameter calibration. The potential of a urea SCR system for reducing diesel $NO_x$ emission is shown for FTP75 and US06 emission standard test cycle.

• Atmosphere
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• v.30 no.3
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• pp.209-220
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• 2020

Seasonal predictability and variability of tropical storms (TCs) simulated in the Global Seasonal Forecast System version 5 (GloSea5) of the Korea Meteorological Administration (KMA) is assessed in Northern Hemisphere in 1996~2009. In the KMA, the GloSea5-Global Atmosphere version 3.0 (GloSea5-GA3) that was previously operated was switched to the GloSea5-Global Coupled version 2.0 (GloSea5-GC2) with data assimilation system since May 2016. In this study, frequency, track, duration, and strength of the TCs in the North Indian Ocean, Western Pacific, Eastern Pacific, and North Atlantic regions derived from the GloSea5-GC2 and GloSea5-GA3 are examined against the best track data during the research period. In general, the GloSea5 shows a good skill for the prediction of seasonally averaged number of the TCs in the Eastern and Western Pacific regions, but underestimation of those in the North Atlantic region. Both the GloSea5-GA3 and GC2 are not able to predict the recurvature of the TCs in the North Western Pacific Ocean (NWPO), which implies that there is no skill for the prediction of landfalls in the Korean peninsula. The GloSea5-GC2 has higher skills for predictability and variability of the TCs than the GloSea5-GA3, although continuous improvements in the operational system for seasonal forecast are still necessary to simulate TCs more realistically in the future.

• Atmosphere
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• v.24 no.3
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• pp.403-417
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• 2014

Future changes in seasonal mean temperature and precipitation over East Asia under anthropogenic global warming are investigated by comparing the historical run for 1979~2005 and the Representative Concentration Pathway (RCP) 4.5 run for 2006~2100 with 20 coupled models which participated in the phase five of Coupled Model Inter-comparison Project (CMIP5). Although an increase in future temperature over the East Asian monsoon region has been commonly accepted, the prediction of future precipitation under global warming still has considerable uncertainties with a large inter-model spread. Thus, we select best five models, based on the evaluation of models' performance in present climate for boreal summer and winter seasons, to reduce uncertainties in future projection. Overall, the CMIP5 models better simulate climatological temperature and precipitation over East Asia than the phase 3 of CMIP and the five best models' multi-model ensemble (B5MME) has better performance than all 20 models' multi-model ensemble (MME). Under anthropogenic global warming, significant increases are expected in both temperature and land-ocean thermal contrast over the entire East Asia region during both seasons for near and long term future. The contrast of future precipitation in winter between land and ocean will decrease over East Asia whereas that in summer particularly over the Korean Peninsula, associated with the Changma, will increase. Taking into account model validation and uncertainty estimation, this study has made an effort on providing a more reliable range of future change for temperature and precipitation particularly over the Korean Peninsula than previous studies.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.5
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• pp.643-653
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• 2014

High-capacity video, control and situation awareness data should be transmitted efficiently to control robots properly in the ground unmanned system, which requires the technology maximizing the communication range and the data transmission throughput. This technology is connected to the OFDMA(Orthogonal Frequency Division Multiple Access)-MIMO(Multiple Input Multiple Output) transmission technology under the limited bandwidth and transmission power. In this paper, we design MIMO communication system for ground unmanned systems, and investigate the data reception performance experimentally, comparing with SISO(Single Input Single Output) system. Experiment results show that the data reception performance of MIMO is significantly improved compared to that of SISO, e.g. 4dB gain of sensitivity and 5dB of SNR at the value MPR = 1, for the mobile stations with $2{\times}2$ STBC diversity.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.736-742
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• 1996

This study was carried out to investigate the effect of the lactoperoxidase (LP) system on the acid production of gel type yogurt. The LP system was activated by adding freshly prepared solutions of 1 ppm (v/w) lactoperoxidase and three different concentrations (0.125 mM, 0.25 mM, 0.5 mM) in equimolar ratios of KSCN and $(H_{2}O_{2}$, In 0.25 mM treated samples for the 4 hr fermentation resulted in titratable acidity of $0.4{\%}$, pH of 5.06, lactic acid bacterial count of $3.0{\times}10^{8}\;CFU/ml and acetaldehyde concentration of 10.2 ppm, whereas the untreated samples were 1.0%, 4.54, $4.7{\times}10^{9}\;CFU/ml and 18.0 ppm, respectively. The residual amount of KSCN in 0.25 mM treated samples was determined during the experiments, which decreased to 4.4 ppm. There was no detectable $(H_{2}O_{2}$ for 6 hr fermentation. However, residual KSCN and $(H_{2}O_{2}$ concentrations in 0.5mM treated samples were 5.7 and 8.4 ppm, respectively. These results have indicated that the optimum concentration of $(H_{2}O_{2}$ and KSCN to activate the LP system was 0.25 mM each.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1305-1310
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• 2016

• Archives of Plastic Surgery
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• v.44 no.5
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• pp.470-471
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• 2017