• Transactions of the Korean hydrogen and new energy society
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• v.33 no.3
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• pp.183-201
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• 2022

In this study, economic feasibility analysis was performed when various hydrogen production and transport technologies were applied to derive hydrogen supply plans by period. The cost of hydrogen may vary depending on several reasons; configuration of the entire cycle supply path from production, storage/transportation, and utilization to the cost that can be supplied to consumers. In this analysis, the hydrogen supply price according to the hydrogen supply route configuration for each period was analyzed for the transportation hydrogen demand in metropolitan area, where the demand for hydrogen is expected to be the highest due to the expansion of hydrogen supply.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.684-691
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• 2022

Hydrogen fuel cell electric vehicles are typically refueled at a wide range of temperatures (-40℃ to 85℃) in the hydrogen refueling station in accordance with the worldwide accepted standard. Currently, there is no traceable method by which to verify and calibrate the hydrogen flowmeters to be used at hydrogen refueling stations except for a water calibration process as a conventional method. KRISS hydrogen field test standard based on the gravimetric principle was developed to verify the measurement accuracy of the mass flowmeter to be used at hydrogen refueling stations for the first time in Korea.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.205-211
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• 2023

Hydrogen gas is light and diffuses very quickly. Therefore, when a leakage accident occurs, the damage is great, so a technology that can quickly measure the leakage in the air at a long distance is needed. In order to develop hydrogen gas leaked in the atmosphere in a non-contact manner, an experiment was performed to measure hydrogen gas using a lidar technology using the Raman effect. Hydrogen Raman signals were detected using a UV LED light source, which is a Raman light source, and a spectrometer in the ultraviolet region including an optical filter in the 400-430 nm band. To develop this, a Raman lidar optical structure was designed to measure the hydrogen Raman signal at a certain distance, and the hydrogen Raman spectrum was confirmed using a standard gas to evaluate the performance of this optical structure. The linearity was found to be 0.99 using hydrogen standard gas (10, 50, 100, 500, 1,000 ppm). Accordingly, a Raman lidar capable of measuring hydrogen gas rapidly diffusing in the air in an open state was developed to improve the limitations of existing hydrogen sensors.

• Journal of Sasang Constitutional Medicine
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• v.11 no.2
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• pp.251-266
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• 1999

1. Purpose : The purpose of this study was to determine the effects of Chungsimyeunjatang on the cerebral neurons injured by hydrogen peroxide($H_2O_2$). 2. Methods : I observed cell viability in mouse cerebral neurons exposed to hydrogen peroxide by NR assay and MTT assay and determined lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide. After administration of Chungsimyeunjatang water extracts, I observed significant changes of cell viability, lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide. 3. Results : Hydrogen peroxide showed neurotoxicity. Cell viability in mouse cerebral neurons exposed to hydrogen peroxide decreased in NR assay and MTT assay. Lipid peroxidation and amounts of LDH release in mouse cerebral neurons exposed to hydrogen peroxide increased. Chungsimyeunjatang was very effective in blocking hydrogen peroxide-induced neurotoxicity.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.467-475
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• 2007

This study was conducted to examine temperature effects on hydrogen production in anaerobic fermentation. 18 batch reactors were operated at mesophilic ($35^{\circ}C$) and thermophilic conditions ($55^{\circ}C$) to achieve maximum hydrogen production in anaerobic fermentation. Optimum hydrogen production conditions were also investigated at each temperature. Different trends were observed regarding pH effects on hydrogen production. This effect was not significant for mesophilic fermentation ($35^{\circ}C$). In this case, pH may not drop to interfere hydrogen production during the test. However, hydrogen production decreased without pH control for thermophilic condition ($55^{\circ}C$). Effects of heat treatment were observed for both fermentation process. Hydrogen production with heat treatment was higher than hydrogen production without heat treatment for both fermentation processes. The amount of produced hydrogen for each substrate concentration with temperature changes showed that more hydrogen was produced at $35^{\circ}C$ than at $55^{\circ}C$.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.3
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• pp.342-347
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• 2007

The research on production and application of hydrogen as an alternative energy in the future is being carried out actively. It hydrogen storage is necessary in order that user use hydrogen economically without much difficulty. Among the ways of hydrogen storage the method which is compressed hydrogen gas by high pressure is easier for application than other methods. In this study, we have been calculated gas with changing pressure and temperature variation of container wall through applied to mass and energy balance equation when compressing hydrogen by high pressure, and also to Beattie-Bridgeman equation of state for the kinetic of hydrogen. We will apply above date as a preliminary for design of hydrogen storage tank.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.2
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• pp.89-97
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• 2004

A heavy duty hydrogen enriched CNG engine has the possibility to obtain stable operation at ultra lean condition and to reduce emission extremely. And it can also serve as a so called bridge technology between the current fossil fueled engine and the future hydrogen power system. The emission, torque and brake thermal efficiency characteristics of a heavy-duty hydrogen-CNG engine were investigated to determine the proper mixing rate of hydrogen and CNG. It was found that the proper mixing rates at ${\lambda}=1.4$ and ${\lambda}=1.6$ were around 20% and 30% for hydrogen addition rate respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.3
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• pp.228-234
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• 2004

It was discussed about explosion danger of hydrogen gas experimentally that could be happen during the handling and using. Hydrogen concentration was varied from 10 to 60 vol% for get the explosion characteristics of hydrogen and 5 kinds of cylindrical vessel were used to find the explosion characteristics of hydrogen according to the vessel volume. Initial pressure of hydrogen-air mixture was varied from 0.6 to 2 kg/cm2. Based on the experiment, explosion pressure was most high near the 30vol% of hydrogen and explosion pressure was increased slightly according to the increase of vessel volume but explosion pressure rise rate was decreased. Explosion pressure was increased linearly proportional to the initial pressure of gas mixture.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.76-76
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• 2010

The interaction of hydrogen (H) and ZnO surfaces has been investigated using a temperature programmed desorption (TPD) technique. When the surface is exposed to atomic hydrogen below 400 K, hydrogen is adsorbed on the surface. As the hydrogen exposure increases, bulk diffusion of hydrogen takes place. The existence of surface and bulk hydrogen has been confirmed using X-ray photoelectron spectroscopy (XPS). When the ZnO(000-1) surface dosed with hydrogen is heated, surface hydrogen is desorbed at 432 K and bulk hydrogen is evolved at ~539 K. Diffusion of hydrogen into the ZnO bulk is an activated process, and the activation energy is estimated to be 0.19 eV. Diffusion of hydrogen on the ZnO(10-10) surface is also investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.2
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• pp.131-139
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• 2000

A direct hydrogen liquefaction equipment has been developed and tested, which consists of a GM refrigerator, a liquefaction vessel, a radiation shield, a cryostat, and an ortho-para converter with catalyst. The effect of ortho-para hydrogen conversion on the performance of hydrogen liquefaction has been investigated. The time needed for the hydrogen liquefaction process with hydrogen pressure charge of 4 atm was delayed to around 75 minutes, and the liquefied mass flow rate of the hydrogen was about 0.0150∼ 0.0205 g/s when the hydrogen was liquefied with the direct hydrogen liquefaction system considering ortho-para conversion. With ortho-para conversion, the liquefied mass flow rate decreased up to 20%. Considering ortho-para conversion, there were up to 30% increase in the work input per unit liquefied mass flow rate. When the ortho-para conversion was considered, FOM decreased to be about 0.031∼0.045.