• Transactions of the Korean hydrogen and new energy society
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• v.31 no.6
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• pp.522-529
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• 2020

This study evaluated the effect of improving the atmospheric environment based on the premise that the supply of hydrogen fuel cell vehicles (HFCV) will be achieved as many as the number of vehicles presented in the hydrogen economy activation roadmap announced by the Korean government in January 2019. The HFCV supply target (2.7 million passenger cars) suggested in the hydrogen economy revitalization roadmap was logically allocated to the five major metropolitan areas in Korea. Air pollution damage costs by region were calculated by reflecting the basic unit of damage cost to the estimated air pollutant emissions. As a result, it was confirmed that the benefits per unit of some cities in Gyeonggi-do were derived more than major cities in the metropolitan area.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.1
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• pp.58-64
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• 2006

In order to examine the effect of humidity on hydrogen embrittlement of STS 444 weld zone for boiler with dry and wet welding conditions, this paper was carried out the accelerated hydrogen osmosis test and the electrochemical Tafel polarization test. In 0.5M $H_2SO_4$ + 0.01M $As_20_3$ solution, this test is added to load of $1400kg/cm^2$ together with hydrogen osmosis by current of $50 {mA/cm^2}$ for 60 min.. The electrochemical Tafel polarization test was carried out in 0.5M $H_2SO_4$ + 0.01M $As_20_3$ solution. Therefore, the effect of humidity on hydrogen embrittlement of STS 444 was considered. The main results are as following: On the basis of hydrogen embrittlement mechanism, that is, integrated electrochemical polarization characteristics with the established mechanism of hydrogen embrittlement, the reduction rate of corrosion current density of weld zone in the wet weld condition is larger than in the dry condition. We can nondestructively predict the degree of hydrogen embrittlement of STS 444 weld zone for boiler through the reduction rate of electrochemical corrosion current density.

• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1748-1751
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• 2017

Reduced activation ferritic/martensitic (RAFM) steels are widely applied as structural materials in the nuclear industry. To investigate hydrogen's effect on RAFM steels' elastic properties and the mechanism of that effect, a procedure of first principles simulation combined with experiment was designed. Density functional theory models were established to simulate RAFM steels' elastic status before and after hydrogen's insertion. Also, experiment was designed to measure the Young's modulus of RAFM steel samples with and without hydrogen charging. Both simulation and experiment showed that the solubility of hydrogen in RAFM steels would decrease the Young's modulus. The effect of hydrogen on RAFM steels' Young's modulus was more significant in water-quenched steels than it was in tempering steels. This indicated that defects inside martensite, considered to be hydrogen traps, could decrease the cohesive energy of the matrix and lead to a decrease of the Young's modulus after hydrogen insertion.

• Journal of the Korean institute of surface engineering
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• v.47 no.1
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• pp.7-12
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• 2014

The characteristics of oxidation for the Zry-4 was measured in the $800^{\circ}C$ and high steam pressure (50 bar, 75 bar, 100 bar) conditions, using an apparatus for high pressure steam oxidation. The effect of accelerated oxidation by high-pressure steam was increased more than 60% in hydrogen-charged cladding than normal cladding. This difference between hydrogen charged claddings and normal claddings tends to be larger as the higher pressure. The accelerated oxidation effect of hydrogen charging cladding is regarded as the hydrogen on the metal layer affects the formation of the protective oxide layer. The creation of the sound monoclinic phase in Zry-4 oxidation influences reinforcement of corrosion-resistance of the oxide layer. The oxidation is estimated to be accelerated due to the creation of equiaxial type oxide film with lower corrosion resistance than that of columnar type oxide film. When tetragonal oxide film transformed into the monoclinic oxide film, surface energy of the new monoclinic phase reduced by hydrogen in the metal layer.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.96-101
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• 2010

The purpose of this study is to investigate the effect of water extract from Artemisiae Argi Folium Fermented with Sacchromyces cerevisiae (AFS) on hydrogen peroxide production within human hepatocyte HepG2 cells treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. AFS (0~400 ug/mL) was treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. And the intracellular productions of hydrogen peroxide were measured by dihydrorhodamine 123 (DHR) assay. AFS showed the restoration of the intracellular productions of hydrogen peroxide which were reduced by gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde in HepG2 Cells. AFS could be supposed to have the hepatoprotective effect related with hepatocytologic signaling activity against gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde.

• BMB Reports
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• v.28 no.6
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• pp.490-493
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• 1995

We investigated the effect of hydrogen peroxide-treated metallothionein on the hepatic xanthine oxidase activity in vitro. When the metallothionein was preincubated with 1 mM of hydrogen peroxide, the activity of xanthine oxidase and type conversion were elevated dose-dependently by the addition of metallothionein into the reaction mixture. While increasing the treatment of hydrogen peroxide to the $50{\mu}g$of metallothionein, the xanthine oxidase activity and type conversion ratio were remarkably elevated dose dependently compared to the control. When cadmium ion was added to the reaction mixture, the increasing pattern of the enzyme activity was similar to the effect of hydrogen peroxide-treated metallothionein. DTT or penicillamine restored the increasing activity and type conversion of xanthine oxidase by the cadmium ion to the control level.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.6
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• pp.1379-1384
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• 2009

The purpose of this study is to investigate the effect of water extract from Artemisiae Argi Folium Fermented with Lactobacillus pentosus (AFL) on hydrogen peroxide production within human hepatocyte HepG2 cells treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. AFL (0~400 ug/mL) was treated with gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde. And the intracellular productions of hydrogen peroxide were measured by dihydrorhodamine 123 (DHR) assay. AFL showed the restoration of the intracellular productions of hydrogen peroxide which were reduced by gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde in HepG2 Cells. AFL could be supposed to have the hepatoprotective effect related with hepatocytologic signaling activity against gallic acid, EtOH, nicotine, acetaminophen, and acetaldehyde.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.1
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• pp.11-20
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• 2019

This study dealt with the tensile strength characteristics of stainless steel 304L steel by hydrogen charging. Especially, the effect of hydrogen charging time on the tensile strength and ductility of 304L stainless steels was evaluated, in conjunction with the observation of their fracture surfaces. The tensile properties of hydrogen-charged 304L stainless steels were also investigated with the variation of tensile loading speeds. The hydrogen amount of 304L stainless steels obviously increased with the increase of hydrogen charging time. The tensile properties of 304L stainless steels were clearly affected by the short term charging of hydrogen. In particular, the elongation of 304L stainless steels decreased with increasing hydrogen charging time, due to the hydrogen embrittlement. It was also found that the tensile properties of hydrogen-charged 304L stainless steels were very sensitive to the crosshead speed for tensile loading.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.1-8
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• 2013

This paper reviews the development status of magnetic refrigeration system for hydrogen liquefaction. There is no doubt that hydrogen is one of most important energy sources in the near future. In particular, liquid hydrogen can be utilized for infrastructure construction consisting of storage and transportation. Liquid hydrogen is in cryogenic temperatures and therefore high efficient liquefaction method must be studied. Magnetic refrigeration which uses the magneto-caloric effect has potential to realize not only the higher liquefaction efficiency > 50 %, but also to be environmentally friendly and cost effective. Our hydrogen magnetic refrigeration system consists of Carnot cycle for liquefaction stage and AMR (active magnetic regenerator) cycle for precooling stages. For the Carnot cycle, we develop the high efficient system > 80 % liquefaction efficiency by using the heat pipe. For the AMR cycle, we studied two kinds of displacer systems, which transferred the working fluid. We confirmed the AMR effect with the cooling temperature span of 12 K for 1.8 T of the magnetic field and 6 second of the cycle. By using the simulation, we estimate the total efficiency of the hydrogen liquefaction plant for 10 kg/day. A FOM of 0.47 is obtained in the magnetic refrigeration system operation temperature between 20 K and 77 K including LN2 work input.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.203-210
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• 2022

In this study, hydrogen embrittlement in Inconel 718 fabricated by selective laser melting (SLM) was investigated. To focus on the effect of the SLM-induced solidification substructure, hydrogen embrittlement behavior of SLM as-built (SLM-AB) sample and that of conventionally produced (Con-S) sample were systematically compared. The detailed microstructural characterization showed that the SLM-AB sample exhibited a solidification substructure including a high density of dislocations and Laves phase, while the Con-S sample showed completely recrystallized grains without any substructure. Although the intrinsic strength in the SLM-AB sample was higher than the Con-S sample, the resistance to hydrogen embrittlement was higher in the SLM-AB sample. Nevertheless, a statistical analysis of the hydrogen-assisted cracks (HACs) revealed that the predominant HAC type of SLM-AB and Con-S samples was similar, i.e., intergranular HAC. The difference in the resistance to hydrogen embrittlement between the SLM-AB and Con-S samples were discussed in terms of the relation between the microstructural feature and its effect on hydrogen accumulation.