• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.562-574
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• 2023

Carbon neutrality has been suggested to overcome the global climate crisis caused by global climate change. Hydrogen energy is a major way to achieve carbon neutrality, and the developments and policies of hydrogen technology have been proposed to achieve this goal. To commercialize hydrogen energy resources, it is necessary to understand the overall value chain composed of hydrogen production, storage, and utilization and to present the direction of technological developments. In this paper the hydrogen strategies of major countries, including Europe, the United States, Japan, China, and South Korea will be analyzed, and hydrogen technologies by value chain will also be explain. This paper will contribute to understanding the overall hydrogen policy and technology, as both policy and technology are summarized.

• 자원환경지질
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• 제22권2호
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• pp.141-150
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• 1989

In order to make economic and geological evaluation of coal in Korea, proximate and ultimate analyses were carried out as well as coal petrological studies such as maceral analyses, vitrinite reflectance and sporinite fluorescence measurement. The coeffcient of correlation between each factor of both conventional utilization and coal petrological parameters were studied as in Table 5 and 6. Their conclusions were as follow: (1) for anthracite, the good parameters of coal rank are mean vitrinite reflectance, carbon content, hydrogen content and H/C atomic ratio: (2) for brown coal and sub-bituminous coal, the good parameters of coal rank are carbon content, calorific value, moisture content, hydrogen content, oxygen content and O/C atomic ratio as well as vitrinite reflectance and sporinite fluorescence. An attempt is made to infer the coalforming environment by utilization of coal petrological analyses and to make comparison of coal analyses with proximate and ultimate analyses throughout the island arc region including Japan, Philippine and Indonesia and continental region including USA, Canada and Australia. As a result, meceral composition of Paleozoic and Mesozoic anthracite are similar to that of the Paleozoic continental coals, which were formed under dry conditions or low water table, but the coalification degree suddenly increased during Daebo orogeny (middle Jurassic to lower Cretaceous). The Tertiary coal resembles those of Tertiary island arc region coal characterized by higher calorific value, volatile matter content and H/C atomic ratio and by the formation of coal under wet conditions or higher water table.

• 한국세라믹학회지
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• 제45권12호
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• pp.807-814
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• 2008

The Cu-Ni-YSZ cermet anodes for direct use of methane in solid oxide fuel cells have been fabricated by electroplating Cu into the porous Ni-YSZ cermet anode. The uniform distribution of Cu in the Ni-YSZ anode could be obtained via pulse electroplating in the aqueous solution mixture of $CuSO_4{\cdot}5H_{2}O$ and ${H_2}{SO_4}$ for 30 min with 0.05 A of average applied current. The power density ($0.17\;Wcm^{-2}$) of a single cell with a Cu-Ni-YSZ anode was shown to be slightly lower in methane at $700^{\circ}C$, compared with the power density ($0.28\;Wcm^{-2}$) of a single cell with a Ni-YSZ anode. However, the performance of the Ni-YSZ anode-supported single cell was abruptly degraded over 21 h because of carbon deposition, whereas the Cu-Ni-YSZ anode-supported single cell showed the enhanced durability upto 52 h.

• 한국수소및신에너지학회논문집
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• 제35권3호
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• pp.249-256
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• 2024

The cement industry emits a large amount of greenhouse gases compared to other industries, with about 60% of CO₂ emissions from the decarbonation of limestone and about 40% from the combustion of fossil fuels. Therefore, the cement industry needs to reduce greenhouse gases through carbon capture, utilization, and storage technology. Capturing CO₂ and synthesizing it into methanol is feasible and also useful as raw material for the chemical industry and as marine fuel. In this study, We aimed to produce methanol from syngas produced by capturing CO₂ emissions. Process simulations were performed under various conditions such as syngas ratio, temperature, and pressure for the production of synthesis gas and methanol, and the results showed that the optimal amount of methanol production at a synthesis gas ratio of 2.03.

• 지구물리와물리탐사
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• 제27권1호
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• pp.1-22
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• 2024

2050 탄소중립을 달성하기 위해 현재 전 세계적으로 이산화탄소 포집·활용·저장(Carbon Dioxide Capture Utilization and Storage, CCUS) 기술이 주목받으면서, 북미, 북해, 중동, 오세아니아 지역을 중심으로 다양한 대규모 이산화탄소 포집·저장(Carbon Dioxide Capture and Storage, CCS) 사업이 활발하게 추진되고 있다. 2050년까지 연간 3,000만 톤급의 국내 저장소 확보가 중요한 국내 상황을 고려하여, 판구조론적 관점에서 해외 대규모 이산화탄소 저장소의 형성 과정과 지질구조 특징을 분석하고자 한다. 이를 위하여 해외 대규모 CCS 프로젝트를 개발 중인 북미, 북해, 오세아니아, 중동 지역의 이산화탄소 저장소의 형성 과정을 GPlates 프로그램을 활용하여 판구조론적인 관점으로 해석하였다. 또한, 각 지역을 대표하는 지중저장소에 대한 탄성파 영상화 결과를 지질구조적 측면에서 해석함으로써, 향후 국내 대규모 저장소 탐사에 활용할 수 있다.

• 자원환경지질
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• 제50권5호
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• pp.389-400
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• 2017

제 21차 유엔기후변화협약당사국 총회(C0P21)의 파리기후협약이 채택됨에 따라 195개국의 범세계적 온실가스 감축 대응에 합의가 이루어졌다. 이에 따라 온실가스 감축에 관련한 다양한 기술들이 거론되고 있고, 그 중에 이산화탄소 포집/저장/전환 기술(CCUS)은 이산화탄소 감축의 실질적인 기여를 할 수 있는 수단으로 주목받고 있다. 하지만 CCUS 기술은 에너지 및 투자 효율성, 잠재적 저장 능력 등 상용화 단계에서 다양한 보완사항이 존재하며, 이를 해결하기 위한 여러 국가들의 연구개발 활동이 적극적으로 이루어지고 있다. 이에 효과적인 연구개발 전략을 수립하기 위해서 각 국의 CCUS 기술 유형 별 수준과 동향을 분석하고 향후 기술발전방향에 대해 대응하는 것이 무엇보다 중요하다. 따라서 본 연구에서는 CCUS 기술에 대한 국가/기술별 특허 동향 분석을 수행하고자 한다. 분석결과, 구간별 기술 성장단계 분석에서 발전기 단계에 있는 것으로 나타났으며, 기술발전 수준이 가장 높은 포집/회수 분야에 60% 이상의 특허 출원이 이루어짐을 보였다. 해외 상위 출원인인 Alstom technology, Toshiba Corp, Mitsubishi heavy 등의 기업에서 이산화탄소를 포집/회수 하는 기술에 중점을 두고 있으며, 국내에서는 정부 연구기관들을 중심으로 포집 분야 외에 기술 초기 단계인 저장, 전환 분야에도 집중하는 것으로 나타났다. 2000년대 후반부터 CCUS기술 특허 출원이 급속히 증가했으며 많은 국가들이 이 기술에 관심을 갖으며 온실가스를 감축하려는 노력을 하고 있다.

• 한국식품영양학회지
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• 제24권4호
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• pp.501-508
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• 2011

Previous studies suggest that polyunsaturated fatty acids with long carbon chains such as eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) have several health benefits. However metabolic consequences of these fatty acids themselves and their regulation of transcriptional activity involving glucose utilization are not well established. Thus, the purpose of this study was to investigate how EPA influx affects cellular lipid accumulation and gene expressions involving $de$ $novo$ lipogenesis in hepatocyte cultures. Compared to oleic acid treatment, EPA treatment showed remarkably decreased cellular TG conversion and accumulation, along with phospholipids at a lower extent. As expected, EPA increased mRNA expression involving fatty acid influx and lipid droplet formation, but did not affect mRNA expression involving glucose utilization. EPA increased transcriptional activity of PPAR-${\alpha}$ and glucose responsive transcription factor when transcription factor binding protein was activated. Taken together, these data suggest that EPA decreases lipid accumulation through increases of the ${\beta}$-oxidation pathway without interruption of glucose utilization.

• 한국미생물·생명공학회지
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• 제24권4호
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• pp.385-392
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• 1996

Bacillus stearotheymophilus, a potent xylanolytic bacterium isolated from soil, was tested for the strain's strategies of pentose utilization and the evidence of substrate preferences. The strain metabolized glucose, xylose, ribose, maltose, cellobiose, sucrose, arabinose and xylitol. The efficacy of the sugars as a carbon and energy source in this strain was of the order named above. The organism, however, could not grow on glycerol as a sole growth substrate. During cultivation on a mixture of glucose and xylose or arabinose, the major hydrolytic products of xylan, B. stearothermophilus displayed classical diauxic growth in which glucose was utilized during the first phase. On the other hand, the pentose utilization was prevented immediately upon addition of glucose. Cellobiose was preferred over xylose or arabinose. In contrast, maltose and pentose were co-utilized, and also no preference on between xylose and arabinose. Enzymatic studies indicated that B. stearothermophilus possessed constitutive hexokinase, a key enzyme of the glucose metabolic system. While, the production of $^{D}$-xylose isomerase, $^{D}$-xylulokinase and $^{D}$-arabinose isomerase essential for pentose phosphate pathway were induced by xylose, xylan, and xylitol but repressed by glucose. Taken together, the results suggested that the sequential utilization of B. stearothermophilus would be mediated by catabolite regulatory mechanisms such as catabolite inhibition or inducer exclusion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권11호
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• pp.5357-5381
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• 2018

Cloud computing offers a wide range of on-demand resources over the internet. Utility-based resource allocation in cloud data centers significantly increases the number of cloud users. Heavy usage of cloud data center encounters many problems such as sacrificing system performance, increasing operational cost and high-energy consumption. Therefore, the result of the system damages the environment extremely due to heavy carbon (CO2) emission. However, dynamic allocation of energy-efficient resources in cloud data centers overcomes these problems. In this paper, we have proposed Energy and Service Level Agreement (SLA) Aware Resource Allocation Heuristic Algorithms. These algorithms are essential for reducing power consumption and SLA violation without diminishing the performance and Quality-of-Service (QoS) in cloud data centers. Our proposed model is organized as follows: a) SLA violation detection model is used to prevent Virtual Machines (VMs) from overloaded and underloaded host usage; b) for reducing power consumption of VMs, we have introduced Enhanced minPower and maxUtilization (EMPMU) VM migration policy; and c) efficient utilization of cloud resources and VM placement are achieved using SLA-aware Modified Best Fit Decreasing (MBFD) algorithm. We have validated our test results using CloudSim toolkit 3.0.3. Finally, experimental results have shown better resource utilization, reduced energy consumption and SLA violation in heterogeneous dynamic cloud environment.

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1773-1784
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• 2008

Effects of various industrially important carbon sources (glucose, sucrose, xylose, gluconate, and glycerol) on shikimic acid (SA) biosynthesis in Escherichia coli were investigated to gain new insight into the metabolic capability for overproducing SA. At the outset, constraints-based flux analysis using the genome-scale in silico model of E. coli was conducted to quantify the theoretical maximum SA yield. The corresponding flux distributions fueled by different carbon sources under investigation were compared with respect to theoretical yield and energy utilization, thereby identifying the indispensable pathways for achieving optimal SA production on each carbon source. Subsequently, a shikimate-kinase-deficient E. coli mutant was developed by blocking the aromatic amino acid pathway, and the production of SA on various carbon sources was experimentally examined during 51 batch culture. As a result, the highest production rate, 1.92 mmol SA/h, was obtained when glucose was utilized as a carbon source, whereas the efficient SA production from glycerol was obtained with the highest yield, 0.21 mol SA formed per mol carbon atom of carbon source consumed. The current strain can be further improved to satisfy the theoretically achievable SA production that was predicted by in silico analysis.