• Journal of Climate Change Research
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• v.9 no.2
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• pp.197-207
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• 2018

The Korean government views coal-fired power plants as the key cause of the fine dust generation, and is developing an energy policy to replace and demolish old coal-fired power plants. According to the Eighth Power Supply Base Plan (2017-2031), the maximum power capacity in 2030 is expected to be 100.5GW, which is 17.9% higher than the current level (85.2GW). The plan aims to reduce the facility size and power generation ratio from nuclear and coal resources to even lower levels than today, and to rapidly expand power generation from new and renewable energy. Despite that, the proportion of coal power generation is still much higher than other resources, and it is expected that the reliance on goal will maintain for next several decades. Under such circumstances, the development, supply, and expansion of clean coal technology (CCT) that is eco-friendly and highly efficient, is crucial to minimize the emission of pollutants such as carbon dioxide and fine dust, as well as maximize the energy efficiency. The Korean government designated the Yong-Dong Thermoelectric Power Plant in Gangneung to develop clean coal power generation, and executed related projects for three years. The current study aims to suggest a plan to develop parts, technologies, testing, evaluation, certification, and commercialization efforts for coal-fired power generation, In addition, the study proposes a strategy to vitalize local economy and connect the development with creation of more jobs.

• Geophysics and Geophysical Exploration
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• v.26 no.4
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• pp.199-210
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• 2023

The physical properties of rocks in reservoirs change after CO₂ injection, we modeled a reservoir with a transition zone within which the physical properties change linearly. The function of the Wolf reflection coefficient consists of the velocity ratio of the upper and lower layers, the frequency, and the thickness of the transition zone. This function can be used to estimate the thickness of a reservoir or seafloor transition zone. In this study, we propose a method for predicting the thickness of the transition zone using deep learning. To apply deep learning, we modeled the thickness-dependent Wolf reflection coefficient on an artificial transition zone formation model consisting of sandstone reservoir and shale cap rock and generated time-frequency spectral images using the continuous wavelet transform. Although thickness estimation performed by comparing spectral images according to different thicknesses and a spectral image from a trace of the seismic stack did not always provide accurate thicknesses, it can be applied to field data by obtaining training data in various environments and thus improving its accuracy.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.313-323
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• 2003

The sliding wear behaviors of Zircaloy-4 nuclear fuel rod were investigated using two support springs with convex and concave shapes in room temperature air and water. The main focus is to compare the wear behavior of various test variables such as slip amplitude, environment, contact contours with different spring shape and a number of cycles. The results indicated that wear volume and maximum wear depth increased with slip amplitude in both air and water, but their trends tended to change according to the spring shapes and test environments. In air condition, the wear volume was controlled by wear debris behavior generated on worn surface. As a result, final wear volume and maximum wear depth decreased if a ratio of protruded wear volume to worn area $(D_p)$ would be saturated to specific value. This is because wear particle layer could accommodate large strain by accumulating and transforming wear particle layer. However, in water condition, metal-to metal contact was more dominant and wear volume was greatly affected by changed mechanical behavior between contact surfaces since wear debris should be generated after repeated plastic deformation and fracture. After wear test, worn surfaces were examined using optical microscope and SEM and details of wear mechanism were discussed using a ratio of wear volume to worn area $(D_e)$ at each test condition.

• Resources Recycling
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• v.27 no.4
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• pp.57-64
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• 2018

Water leaching of tungsten(W) and vanadium(V) was researched from their oxides through mechanochemical (MC) reaction with alkali compounds. Intensive grinding for the mixture of tungsten/vanadium oxide and alkali compounds (NaOH, $Na2CO_3$) was carried out with change of their mixing ratios and grinding duration. Water soluble compounds, $Na_2WO_4$ and $NaVO_3$, were synthesized through MC reaction and their solubilities increased in proportion to the mixing ratio of sodium compound and grinding times. Whereas vanadium leachability was less affected by the mixting ratio and grinding times. The leachabilities of 99.0% were accomplished by a short period of MC treatment, W (30 min.) and V (5 min.). This process enable us to extract W and V from their oxides via a water leaching, and can be applied to the selective recovery of W and V from $DeNO_x$ spent catalysts.

• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.72-81
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• 2022

Numerous studies have investigated the occurrence and fate of microplastics in the environment; however, only limited effort has been devoted to exploring the characteristics of dissolved organic matter (DOM) leached from microplastics. In microplastic (MP)-contaminated environment, MPs are typically mixed with naturally-occurring particles, which interferes with their detection in the environment. Thus, it is necessary to distinguish between the DOM leached from MPs and those leached from natural particles and also to characterize their properties. This study investigated DOM leaching behavior from MPs (polystyrene: PS, polyvinylchloride: PVC) and natural particulates (forest soil: FS, litter leaves: LL) under light, which is considered one of the main weathering processes that affect MPs in the environment. The leached DOM concentrations and fluorescence characteristics were compared under dark versus light conditions. Regardless of the origins, UV light promoted DOM release from all the particulates. More DOM was released from natural particles than from MPs under both conditions. However, the effect of promoting DOM release by UV was more pronounced for MPs than for natural particles. It was observed from fluorescence spectra that the intensity of the humic-like region was substantially reduced when MP-derived DOM was exposed to UV light, whereas the change of intensity was very little for natural particles. Under light conditions, the ratio of protein-like to humic-like fluorescence of MP-derived DOM was higher than that of DOM from natural particles. This study implies that a substantial amount of DOM could be leached from MPs even in MP-polluted environment under UV irradiation. Protein/humic fluorescence ratio could be utilized as a fast probing indicator to separate the two sources of particles under light.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.109-119
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• 2004

This research is an analysis of the water vapor transport change Into the continent due to the global warming effect with the general circulation models. Water vapor transport change from ocean to land increases through the year due to CO2 doubling effect. In Eurasia, it indicates an increase about 170∼350${\times}$06 Mt/day the whole year. In Africa, it shows an decrease every month except November, especially there is the maximum decrease about -350${\times}$106 Mt/day during August-September. In other continents, excluding Eurasia and Africa, the change of water vapor transport vary with the month below $\pm$8.0${\times}$106 Mt/day with the unsystematic patterns. In Eurasia, the change of water vapor transport increases as a whole, but it decrease in desert areas which occupy a high area-ratio. Therefore, except desert areas, the amount of the growth in water vapor transport change concentrate on Asian monsoon area. As a result of monsoon strengthening, available water will grow considerably at the asian monsoon areas.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.601-614
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• 2012

This paper is aimed to analyze the determinants and their relative importance that affect regional competitiveness in the era of globalization and climate change. The panel model was set by a balanced panel data for 7 metropolitan areas & 9 provinces and for the period of 2001~2010. Gross regional income per capita is used as the dependent variable and competitiveness-based factors, economic production factors, and climate change adaptation factors are selected as the explanatory variables. In this study, Model 1(typical regional competitiveness model) and Model 2 (added adaptation to climate change adaptation factors) were compared. The important findings can be summarized as follows. The most influential determinants on regional competitiveness are the ratio of knowledge-based industries and human capital and energy inefficiencies decrease the regional competitiveness. Compared to Model 1, Model 2 showed that the effects of the regional openness and the technology innovation capital are relatively more influential in Model 2. The results of this empirical study provide policy implications to strengthen the regional competitiveness in the future of the era of globalization and climate change.

• Journal of agriculture & life science
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• v.44 no.5
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• pp.137-146
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• 2010

The GyeongNam Province is one of the regions that have first introduced chrysanthemum farming in Korea since the 1960s. The chrysanthemum growers of The GyeongNam Province had strong competitiveness in production and marketing, so the their income ratios were relatively higher than any other growers of other provinces. The income ratio of The GyeongNam Province, however, has continuously decreased and stays currently below ratios of other provinces. The purpose of this paper is to find out which factors have contributed to the decrease in income ratio of GyeongNam Province. The analysis indicates that the increase in production cost was the main causes of rapid drop in income ratio. It is also worth mentioning that the income ratio falls dramatically when oil price (duty-free oil) rises above 700 won per liter.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.4
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• pp.86-94
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• 2015

Torrefaction is a thermochemical process proceeded at the temperature around $250^{\circ}C$ in an inert gas condition. By torrefaction, the hemicellulose portions contained in biomass are broken down to change into the volatile gas which is removed from biomass eventually. The main purpose of biomass torrefaction is to improve the energy density of the biomass to minimize the transport energy consumption, though the flammability can be elevated for transportation. In this study two types of solid biomass fuel, waste wood and rice straw, were torrefied at various temperature range from $200^{\circ}C$ to $300^{\circ}C$ to evaluate the torrefied biomass characteristics. In addition torrefied biomass were tested to evaluate the combustion characteristics using TGA (Thermogravimetric Analysis). After the torrefaction of biomass, the C/H (carbon to hydrogen ratio) and C/O (carbon to oxygen ratio) were measured for aquisition of bio-stability as well as combustion pattern. Generally C/H ratio implies the soot formation during combustion, and the C/O ratio for bio-stability. By torrefaction temperature at $300^{\circ}C$, C/H ratio and C/O ratio were increased by two times for C/H and three times for C/O. The torrefied biomass showed similar TGA pattern to coal compared to pure biomass; that is, less mass decrease at lower temperature range for torrefied biomass than the pure biomass.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.5
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• pp.459-467
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• 2014

The catalytic steam reforming of toluene, a major component of biomass tar, was studied using several catalysts at various temperatures $400-800^{\circ}C$, kind of metal, and metal loading content. Ru and K promoted Ni-base catalyst were prepared, and used for steam reforming of toluene with steam/toluene molar ratio of 25. Concentration of toluene in reactant flow is $30g/Nm^3$ that is usual content of tar from biomass gasifier. The result from experiments showed that $H_2$ content in product gas and toluene conversion increased with temperature. Where in high temperature range, CO and $CO_2$ content in product gas were affected mainly by Boudouard reaction. Ni/Ru-K(3wt%)/$Al_2O_3$ catalyst showed best performance on steam reforming of toluene than used catalysts in this study at whole temperature. Catalysts have been characterized by XRD, TG. XRD analysis displayed that Ni particle size on Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was 29.4nm. Activation energy of Ni/Ru-K (3wt%)/$Al_2O_3$ catalyst was calculated 36.8kJ/mol by Arrhenius plot.