• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.607-615
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• 2022

In this study, economic analysis program was developed for economic evaluation of hydrogen production, storage/delivery, and utilization technologies as well as overseas import of hydrogen. Economic analysis program can be used for the estimation of the levelized cost of hydrogen for hydrogen supply chain technologies. This program include five hydrogen production technology on steam methane reforming and water electrolysis, two hydrogen storage technologies (high compressed gas and liquid hydrogen storage), three hydrogen delivery technologies (compressed gas delivery using tube trailer, liquid hydrogen, and pipeline transportation) and six hydrogen utilization technologies on hydrogen refueling station and stationary fuel cell system. In the case of overseas import hydrogen, it was considered to be imported from five countries (Austraila, Chile, India, Morocco, and UAE), and the transportation methods was based on liquid hydrogen, ammonia, and liquid organic hydrogen carrier. Economic analysis program that was developed in this study can be expected to utilize for planning a detailed implementation methods and hydrogen supply strategies for the hydrogen economy road map of government.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.323-330
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• 2019

The 500 MW Korean standard coal-fired power plant is the largest standardized power plant in Korea and has played a pivotal role in domestic power generation for over 20 years. In addition to the aging degradation due to long term operation, the probability of failure of power generation facilities is increasing due to frequent startup and stop caused by the lower utilization rate due to air pollution problem caused by coal-fired power plants. Among them, steam piping plays an important role in transferring high-temperature & pressure steam produced in a boiler to turbine for power generation. In recent years, failure of steam piping of large coal-fired power plant has frequently occurred. Therefore, in this study, failure analysis of high pressure piping weld was conducted. We identify the damage caused by high stress due to abnormal supporting structure of the piping and suggest improved supporting structure to eliminate high stress through microstructure analysis and piping stress analysis to prevent the occurrence of the similar failure of other power plant in the case of repetitive damage to the main steam piping system of the 500 MW Korean standard coal-fired power plant.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.55-64
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• 2018

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to biogas utilization treating organic wastes. In accordance with the government's mid-to long-term policies on bio-gasification and energization of organic wastes, the expansion of the waste-to-energy (WTE) facilities is being remarkably promoted. However, because of the limitation of livestock manure containing low-concentration of volatile solids, there has been increased in combined bio-gasification without installing new anaerobic digestion facilities. The characteristics and common problems of each treatment processes were investigated for on-going 11 bio-gasification facilities. The seasonal precision monitoring of chemicophysics analysis on anaerobic digestor samples was conducted to provide guidelines for design and operation according to the progress of biogas utilization. Consequently, Major problems were investigated such as large deviation of organic materials depending on seasons, proper dehumidification of biogas, pretreatment of hydrogen sulfide, operation of power generation and steam. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure), research the facilities problem through field investigation.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.1-7
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• 1989

This study was performed to obtain the optimal condition that hydrolyzed exploded pine(Pinus densiflora), oak(Quercus serrata) and birch wood(Betula platyphylla var. japonica) by using sulfuric acid. The results obtained were summarized as follows: In hydrolysis of wood meal with sulfuric acid. maximum yield of sugar appeared that pine was 12 hours. oak and birch were 24 hours with 65% sulfuric acid. Futhermore, when wood meal and exploded woods were hydrolyzed with 65% sulfuric acid at $23^{\circ}C$ for 6 hours(primary hydrolysis), diluted to 3% and hydrolyzed again at $100^{\circ}C$ for 2 hours(secondary hydrolysis), the maximum sugar yield of wood meals were 6 hours. those of higher steam exploded pine wood was 3 hours. of lower steam exploded oak and birch woods were 6 hours. The sugar analyses of exploded wood showed that the amount of arabinose and xylose residue rapidly decreased. content of nemicelluose decreased with increase of steaming time and pressure.

• Journal of the Korean Wood Science and Technology
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• v.17 no.2
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• pp.65-73
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• 1989

Steam explosion process is an efficient pretreatment method for sparating and utilizing wood main components has attracted attention in utilization of ligno-cellulosic biomass. In order to obtain the effective pretreatment condition. this study was made explosion apparatus. examined the composition. extraction of exploded wood. Wood chips of pine(Pinus densiflora oak (Quercus serrata) and birch wood (Belula platyphylla var. japonica) were treated with a high pressure steam(20-30 kg/$cm^2$, 2-6 minutes). The results can be summarized as follow; In analysis of exploded wood(EXW). It was found arabinose residues rapidly decreased with increasing of steaming time and pressure. Extractives of EXW with sodium hydroxide increased with increasing of steaming-time and- pressure especially extractives 1% sodium hydroxide has higher than other extracted method extractives of hard wood(oak, birch) has higher than pine wood. In EXW extracted with sodium hydroxide and methanol lignin was partially delignified alkali extraction was more delignified than methanol extraction hardwood than pine wood.

• Journal of the Korean Solar Energy Society
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• v.21 no.4
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• pp.29-35
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• 2001

The chemical heat storage as the one way of utilization for high temperature solar energy was considered. The stram reforming reaction of methane was chosen for endothermic reaction. The reactor was made of stainless steel tube and it's dimension was 0.635 cm I.D. and 30 cm long, coiled tube because of the geometry requirement of solar receiver The effects of space velocity and reactants mole ratio on the methane conversion and CO selectivity were examined. From the experimental results, the optimum steam/methane mole ratio was determined.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.5
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• pp.416-423
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• 2009

High-temperature steam electrolysis (HTSE) using solid oxide cell is a challenging method for highly efficient large-scale hydrogen production as a reversible process of solid oxide fuel cell (SOFC). The overall efficiency of the HTSE hydrogen and synthesis gas production system was analyzed thermo-electrochemically. A thermo-electrochemical model for the hydrogen and synthesis gas production system with solid oxide electrolysis cell (SOEC) and very high temperature gas-cooled reactor (VHTR) was established. Sensitivity analyses with regard to the system were performed to investigate the quantitative effects of key parameters on the overall efficiency of the production system. The overall efficiency with SOEC and VHTR was expected to reach a maximum of 58% for the hydrogen production system and to 62% for synthesis gas production system by improving electrical efficiency, steam utilization rate, waste heat recovery rate, electrolysis efficiency, and thermal efficiency. Therefore, overall efficiency of the synthesis production system has higher efficiency than that of the hydrogen production system.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.545-548
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• 2006

This study has been carried out to examine the properties of concrete according to replacement ratio and curing method of fly ash, in order to increase utilization of it. As the result of experiments, the 7 days of early age strength presented around 20MPa, up to 20% of replacement ratio, which is almost the same strength as non-replacement. However, when the replacement ratio was 30%, the strength was decreased to 16MPa, as 20% reduction compared to the non-replacement condition. In 365 days of long term aging, the strength was 5% higher, up to 20% of the replacement ratio, due to the pozzolanic reaction of fly ash. When the replacement ratio was 30%, it presented similar strength development as the non-replacement condition. Steam curing and autoclave curing increased the short age strength, regardless of the replacement ratio of fly ash; however, they don't have an effect on increasing the 365 days of long term strength. Water curing showed high strength development after 28 days, 51.81MPa, which is around 30% higher than air curing, 38.9MPa, steam curing, 38.6MPa, and autoclave curing, 39MPa. Therefore, water curing was examined as one of the very effective curing methods for developing long term strength of concrete.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.26-31
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• 1995

Acetylcellulose(AC) was prepared with steam exploded wood(EXW) and EXW after delignification with sodium chlorite, pine (Pinus densiflora) and oak (Quercus mongolica) woods. The color of acetylated pine and oak exploded wood was brown, degree of substitution(D.S) of pine was 1.47~2.09, and this of oak was 1.49~2.29. The hemicellulose content of acetylated pine and oak exploded wood was 0~3.4% and 1.49~11.3%, individually. The degree of substitution of acetylated wood prepared from delignified EXW in the pine and oak wood was 0.50~0.71 and 0.70~0.88, individually. Hemicellulose content of acetylated EXW with sodium chlorite after delignification in the pine and oak wood was less than 1% and 0.6~2.5%. The color of acetylated wood after delignification was white. IR-spectra of acetylated pine and oak EXW after delignification were found that peaks at around 1740$cm^{-1}$ and 1200$cm^{-1}$ increase markedly, due to ester carbonyl group.

• The Journal of Korean Medical History
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• v.36 no.2
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• pp.99-113
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• 2023

This paper is a study to find the philological basis of Bihoon (鼻熏) therapy. There is no separate philological study of Bihoon therapy to date, and for this reason, there is no clear definition or specific treatment manual. In this study, a related database was created and analyzed by examining literature data related to Bihoon therapy, focusing on Korean traditional medical books. There were about 1,000 data points related to Bihoon therapy in 45 kinds of medical books. They were largely classified into 1. Acute diseases such as insensitivity, 2. Diseases that occur in the upper human body such as nose, head, eyes, and throat, 3. Women's diseases related to childbirth, 4. Treatment of skin diseases and prevention of infectious diseases. In the case of insensitivity treatment, the focus was on awakening the patient's mind, and the treatment of diseases such as the nose, head, eyes, etc. was focused on resolving each symptom. Symptoms related to childbirth were mainly treated for uterine escapism or fainting after childbirth, while skin diseases were mainly treated for diseases that did not heal well, such as amniotic fluid. If a multifaceted approach to non-discipline therapy is added in the future, it is expected that clinical utilization will also be increased.