• Nutrition Research and Practice
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• v.8 no.1
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• pp.27-32
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• 2014

This study investigated the influence of different durations of aerobic exercise on fuel utilization, lactate levels and antioxidative status in trained rats. Forty rats underwent physical training (T, n = 20) or non- training (NT, n = 20) for 6 weeks. For physical training, animals exercised on a treadmill for 30 min 5 days per week. At the end of week 6, the animals in each group were subdivided into BE, DE-0.5, DE-1 and DE-2, which were sacrificed at the end of week 6 without having performed exercise or after exercise on a treadmill for 0.5h, 1h and 2h, respectively, immediately before being sacrificed. The plasma glucose level in DE-2 of the NT group was significantly lower than in the other groups. Muscle and liver glycogen levels were significantly lower in DE-1 and DE-2, but there were no significant differences between DE-1 and DE-2 in the T group. Liver protein in DE-2 of the NT group was significantly lower. Muscle TG levels were decreased in DE-0.5 of the T group, while those of the NT group were decreased in DE-1. FFA levels were increased in DE-0.5 of the T group and in DE-1 of the NT group. Lactate levels were increased in DE-0.5 of the NT group, while they were increased in DE-1 of the T group. Catalase activity of the T group was lower in BE but higher in DE-0.5, DE-1 and DE-2. SOD activities were higher in trained rats, while the GSH/GSSG ratios were higher in BE, DE-0.5 and DE-1 in the T group, and there was no difference in that of DE-2. There were no differences in MDA levels in BE and DE-0.5, but they were significantly lower in DE-1 and DE-2 of the T group. Overall, the results of this study, suggest that training may improve exercise performance by facilitating the mobilization and oxidation of fat and conserving limited carbohydrate storage, and that it may delay the onset of fatigue and enhance the antioxidative defense system, but cannot support two hours of vigorous exercise.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.203-212
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• 2005

Anthropogenic emissions of greenhouse gases, particularly carbon dioxide($CO_2$) which arises mainly as wastes from the fossil fuel burning processes, are causing global warming. The effects of global warming become increasingly felt all over the world including sea level rise and extreme weather. The more direct consequences of the elevated atmospheric $CO_2$ on the ocean is the acidification of the surface ocean which brings a far reaching adverse impact on the life at sea and probably on the whole ecosystem of the planet. Improvement in energy efficiency and use of alternative energy sources are being made to reduce $CO_2$ emissions. However, a rapid transition to alternatives seems unachievable within a few decades due to the constraints on the associated technology and socio-economic factors in the world, since fossil fuels make up approximately 85% of the world's commercial energy demands. It has now been recognized that capture and geological sequestration of $CO_2$ could significantly reduce its emissions from fossil fuel utilization and therefore provides the means to rapidly achieve large reductions in $CO_2$ emissions(excerpts from London Convention, LC/SG 28, 2005). In Korea, well-developed sedimentary basins are spread over the vast continental shelf and slope regions, whereas, the land is densely populated and limited in area. Consequently, the offshore area is preferred to the land for the sites for geological sequestration. The utilization of the offshore area, however, may be subject to international agreements including London Convention. In this paper, the recent trends in technologies and regulations for $CO_2$ capture and geological sequestration are described to encourage its applications in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.2
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• pp.181-187
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• 1996

본 연구에서는 비타민 $B_{2}$ 결핍이 3일간 금식과 6일간 감식시 체내 저장연료 이용에 어떠한 영향을 미치는 가를 알아본 결과, -B2군은 pair-feeding을 감식시켰음에도 불구하고 +B2군에 비해 체중이 유의적으로 낮게 나타났으며 식이 이용효율도 낮았다. 모든 장기, 특히 간장 무게는 -B2군이 +B2군에 비해 무겁게 나타났으며, 감식과 금식시에도 -B2군의 장기무게가 가벼워졌으나 여전히 유의하게 무거웠으며 -B2군의 간장 중성 지방이 높게 나타나 지방간 증상으로 간장이 비대해진 것으로 추정된다. 혈장 포도당과 단백질 함량은 섭식, 금식 및 감식시 +B2군과 -B2군 사이에 유의적인 차이가 없었다. 혈장 중성지방 수준은 +B2군에 비해 -B2군이 섭식시는 높은 수준을 나타냈으나 금식 및 감식시에는 유의적인 차이를 나타내지 않았다. 간장 중성 지방도 이와 유사한 경향을 나타내었다. 혈장 유리지방산 수준은 섭식시에는 +B2군과 -B2군 사이에 유의적인 차이가 없었으나, 금식으로 인해 +B2군은 유리지방산 수준이 증가하였고 -B2군은 오히려 감소하여 -B2군이 +B2군 보다 낮게 나타났다. 그러므로 비타민 $B_{2}$ 결핍으로 인해 이 유리지방산의 유리가 원활히 일어나지 않았거나, 비타민 $B_{2}$ 결핍으로 인해 지방산화가 저해된 것이 금식으로 지방이 에저지원으로 이용되어야만 하는 상황이 발생하여 감소된 지방산 산화가 다소 회복된 것으로 추정된다. 금식 및 감식시 +B2군에 비해 -B2군이 근육단백질 수준은 높은 경향을 나타내었고 근육 글리코겐 수준은 낮은 경향을 나타내어 -B2군이 심각한 비타민 $B_{2}$ 결핍으로 저지방이나 근육단백질을 이용하지 못하게 됨에 따라 근육 글리코겐을 이용한 것으로 추정된다. 이는 +B2군에 비해 -B2군의 뇨중 총질소 배설량이 적은 것으로도 재확인되었다. 그러므로 금식이나 감식시 체지방이나 체단백질을 이용하는 에너지 보충 적응기전이 일어나야 하나 비타민 $B_{2}$ 결핍상태에서는 이러한 체내 열량공급이 지장을 받게 되며, 체단백질 이용저하로 포도당 신생이 영향을 받아 장기간의 금식 또는 감식시에는 혈장 포도당 수준도 낮아질 것으로 예상된다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.313-320
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• 2010

Hydrogen energy begins to grab the attention as a leading alternative to solve environmental pollution and energy issue. The preparation for the hydrogen energy age is at the primary stage. But it is expected that the utilization of hydrogen energy is a feasible objective through government policy and invigoration of studies in relevant fields of industry. The preparation and research are badly in need to equip a ship with hydrogen energy engine. Some researches on ship with fuel cell are in progress, however, considering a ship that has become larger and it is being operated in special circumstances, the researches on ship with hydrogen energy engine is keenly necessary. And more concerns and supports are required in this regard.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.81-91
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• 2011

Current fuel ethanol research and development deals with process engineering trends for improving biotechnological production of ethanol. Recently, a large amount of studies regarding the utilization of lignocellulosic biomass as a good feedstock for producing fuel ethanol is being carried out worldwide. The plant biomass is mainly composed of cellulose, hemicellulose and lignin. The main challenge in the conversion of biomass into ethanol is the complex, rigid and harsh structures which require efficient process and cost effective to break down. The isolation of microorganisms is one of the means for obtaining enzymes with properties suitable for industrial applications. For these reasons, crude cultures containing cellulosic biomass degrading microorganisms were isolated from rice field soil, cow farm soil and rotten rice straw from cow farm. Carboxymethyl cellulose (CMC), xylan and Avicel (microcrystalline cellulose) degradation zone of clearance on agar platefrom rice field soil resulted approximately at 25 mm, 24 mm and 22 mm respectively. As for cow farm soil, CMC, xylan and Avicel degradation clearancezone on agar plate resulted around at 24mm, 23mm and 21 mm respectively. Rotten rice straw from cow farm also resulted for CMC, xylan and Avicel degradation zone almost at 24 mm, 23 mm and 22 mm respectively. The objective of this study is to isolatebiomass degrading microbial strains having good efficiency in cellulose hydrolysis and observed the effects of different substrates (CMC, xylan and Avicel) on the production of cellulase enzymes (endo-glucanase, exo-glucanase, cellobiase, xylanase and avicelase) for producing low cost biofuel from cellulosic materials.

• Journal of the Korean Society of Tobacco Science
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• v.2 no.1
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• pp.61-67
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• 1980

The greenhouse hulk curing and drying system utilizing the direct solar energy was tested to see how much fuel could be saved for curing flue-cured tobacco at the Daegu Experiment Station, Korea Tobacco Research Institute (North latitute: 35$^{\circ}$49'), in 1979. The structure consists of transparent fiberglass exterior, polyurethan boards covered with galvanized iron as the heat absorbers and insulation boards, air duct in which the air is introduced to the furnace room of bulk curing barn, and gravel heat storage system. All exterior surface of heat absorbers, air duct, and gravels were coated with black paint. The air temperature and total radiation were 20.5 to 35.5$^{\circ}C$ and 1004.2 to 1436.2 cal/$\textrm{cm}^2$ during the 3 replicated curing tests, respectively. The greenhouse bulk curing and drying system was able to cut fuel consumption by 25 percent compared with the conventional bulk curing barn. The maximum temperatures for the top absorber and the inlet air of the system were 89$^{\circ}C$ and 64$^{\circ}C$, respectively, and the average temperature of inlet air was higher than that of conventional one by 18$^{\circ}C$.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.221-226
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• 2015

Ru catalysts supported on $CeO_2$ were synthesized by an impregnation method and characterized by numerous analytical techniques including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Upon utilization of these catalysts for methane dry reforming with a $CH_4/CO_2$ ratio of 1:1 at different temperatures ranging from 550 to $750^{\circ}C$, the $Ru/CeO_2$ catalysts have shown to be active. In particular, Ru(0.55wt%) supported on $CeO_2$ (1) prepared by a hydrothermal method exhibited excellent activity with the conversion of > 75% at $750^{\circ}C$. In addition, the catalyst also proved to be highly stable for at least 47 h without catalyst deactivation under the dry reforming conditions.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.35-43
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• 1998

Electrodes using for the anode electrode of direct methanol fuel cell with Pt/C and Pt/Ru/C catalyst were prepared and characterized by SEM, TEM, thermal analysis and electrochemical analysis. The half cell tests were carried out with 1 M $H_2SO_4$ electrolyte and 1 M $CH_3OH$ in order to evaluate the electrode performance. The employed electrochemical methods were cyclic vol-tammetry and potentiodynamic polarization experiments. It was found that 20 w% polytetrafluoroethylene (PTFE) content in catalyst showed the best performance due to the best platinum utilization on PTFE-containing catalyst layer. It was found that Pt/Ru/C binary catalyst inhibited the poisoning of anode electrode showing improved performance compared to the Pt/C catalyst by the adsorption of oxygen containing species on the electrode surface at same time. The apparent activation energy for methanol oxidation on the Pt/Ru/C and Pt/C catalyst layer was 11.60 kJ/mol and 26.85 kJ/mol, respectively.

• Nutritional Sciences
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• v.9 no.2
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• pp.112-116
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• 2006

This study investigated the effect of physical training on the utilization and recuperation of stored fuel with exercise in rats. For physical training, animals were exercised on treadmill for 30 minutes everyday. Forty eight rats were given either a physical training or no training for 4 weeks and were then subdivided into 3 groups: before-exercise (BE); during-exercise (DE); after-exercise (AE). The DE group was exercised on treadmill for 1 hour just before being sacrificed Animals in the AE group were allowed to take a rest for 2 hours after being exercised like the DE group. Glucose and free fatty acids were compared in plasma. Glycogen and triglycerides were compared in liver and skeletal muscle. Protein were compared in plasma, liver and skeletal muscle of rats. Plasma glucose levels of trained group were not significantly different from those of non-trained group. Muscle glycogen levels of trained group were significantly higher than those of non-trained group. Liver glycogen level of trained group was also significantly higher than that of non-trained group in DE while was not significantly different from those of non-trained group in BE and AF. Plasma free fatty acid levels of trained group were significantly higher than those of non-trained group in BE and AE. Muscle triglyceride levels of trained group tended to be higher than those of non-trained group in BE and DE and significantly higher than those of non-trained group in AF. Plasma and muscle protein levels of trained group were not significantly different from those of non-trained group. liver protein levels of trained group were not significantly different from those of non-trained group in BE and DE but were significantly higher than that of non-trained group in AE. Thus, it is suggested that an even moderate physical training may delay the onset of fatigue and improve exercise performance by facilitating the mobilization and oxidation of fat and conserving limited carbohydrate store.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.533-539
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• 2013

Recently, Ionic Polymer Metal Composite (IPMC) systems receive great attention in the fields of the medical and biomedical Engineering because of several merits in terms of new actuators and sensors and fuel cell materials. When the voltage is excited to IPMC system, it moves. Conversely, if there are any movement on the IPMC, the IPMC has charge voltage by the internal properties. Therefore the IPMC can be used as a motion sensor or force sensor. In this paper, we identify characteristics of the IPMC and control its movements from remote locations by the smart-phone system based on visual information for monitoring. Additionally, control of movements of the IPMC is realized by transmit motion commands using the smart-phone system with the blue-tooth communication. Unfortunately, there are some deficiencies to perfectly attain physical properties of the IPMC systems from our experiments in this paper. However, in its utilization point of view, we demonstrate that the IPMC has some potentials as new sensors, actuators, and fuel cells.