Jo Apr 7, 2026
Metal hydrides have been widely used in H2 storage application because of their superior property. Among them, perovskite-type metal hydrides are considered as promising candidates of hydrogen storage due to their diversity in crystalline structure and distinctive physicochemical properties.
This attracted many researchers to the investigation into them. However, only a few papers have focused on the structure, thermal analysis and dehydrogenation kinetic properties of KxNa1-xMgH3 hydride, and yet they failed to provide full theoretical insights into the material properties of double perovskite-type hydride NaKMg2H6.
Jo Son Il, a section head at the Faculty of Material Science and Technology, elucidated the hydrogen storage property of metal hydride NaKMg2H6 by the first-principles.
Based on electronic properties, geometric factors, elastic constants and self-consistent phonon calculations, he found that NaKMg2H6 is dynamically and mechanically stable in cubic phase at elevated temperatures.
He illustrated that gravimetric and volumetric H2 storage capacities are 5.19% and 72.548g/L, respectively, and H2 desorption temperature is 470.4K.
You can find the details in his paper “Elucidating the Hydrogen Storage Property of Perovskite-Type Metal Hydride NaKMg2H6 from First-Principles” in “Proceedings of KUTIC-2025”.
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Jo Apr 6, 2026
The rapid development of modern industry requires products with good mechanical properties and light weight and thus, the application of Al and its alloys attracts a great deal of attention. Inclusions and gas in molten aluminum decrease its fluidity and make its structure rough to decrease the castability and serve as the source of crack. Also, they decrease the workability and surface finish, and especially it is unfavorable to the toughness and fatigue strength. Therefore, there have been many researches to remove these inclusions and gas.
A researcher prepared KCl-NaCl-NaF-Na2AlF6 system refining agent and estimated the refining efficiency by measuring the density of aluminum to determine the effective composition of KCl-NaCl-NaF-Na2AlF6 system. Some components of KCl-NaCl-NaF-Na2AlF6 generate gas for removing gas, but their main refining action is the absorption of oxide inclusions. In other words, the hydrogen removal effect is not so high. Therefore, it is necessary to select and use an additive to increase the amount of generated gas for improving the hydrogen removal effect.
Ri Hyok, a researcher at the Faculty of Metallic Engineering, selected an additive to improve the refining efficiency of NaCl-KCl-Na2SiF6-NaF system-compound refining agent for gas impurities in molten aluminum for continuous casting, and determined its amount.
Based on the relationship between the partial pressure and the chemical potential of refining gas and those of the hydrogen in molten aluminum, he induced a formula for determining the amount of additives. He conducted a metallic microscope analysis of newly-refined aluminum to confirm the refining efficiency.
He found that the amount of NaNO3 which was selected as an additive is 0.2% of that of refined aluminum and at that time the amount of carbon is 0.1%.
You can find his paper “Improvement of the Refining Effect of NaCl-KCl-Na2AlF6-NaF System-Refining Agent for Gas by Adding NaNO3” in “Proceedings of KUTIC-2025”.
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Jo Apr 3, 2026
Ozone is usually produced by the dielectric barrier discharge (DBD) method. The dielectric barrier discharge can be divided into two categories: volume discharge and surface discharge. In the surface discharge, a ceramic plate is used as a dielectric barrier. As an advanced form of single SDBD, double SDBD was proposed, in which striped electrodes were coated on both sides of the ceramic plate. Double SDBD can simultaneously generate two plasma zones on both sides of the ceramic plate to improve energy efficiency compared to single SDBD. However, it is difficult to realize the cooling of the discharge device.
A previous study proposed a double SDBD reactor in which two silver mesh electrodes were coated on one side of an enameled steel plate. However, an enameled steel plate is easy to deform during the fabrication process and it is difficult to make the discharge device larger. In addition, a silver electrode is not practical because of its low resistance to the oxidation of ozone.
Kim Jong Guk, a researcher at the Institute of Nano Science and Technology, has proposed a cylindrical double SDBD device.
The proposed discharge device can simultaneously produce ozone at both the high voltage electrode and the grounded electrode, thus showing great advantages in getting high ozone concentration.
The optimized reactor ensures ozone generation efficiency of 339g/(kW·h) and ozone concentration of 82g/(N·m3).
You can find the details in his paper “Implementation of Double Surface Dielectric Barrier Discharge with Enamel Ozone Tube” in “Proceedings of KUTIC-2025”.
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Jo Apr 2, 2026
Gliding arc discharge (GAD) generates plasma with relatively high electron density and power, and also provides high operating pressure, low fabrication cost and excellent reaction selectivity. In particular, its power levels higher than other atmospheric pressure non-equilibrium discharges such as dielectric barrier or corona discharges have constantly expanded its applications in combustion support, surface treatment, fuel reforming, chemical synthesis, environmental remediation, etc.
Kim Yong Jun, a researcher at the Faculty of Physical Engineering, has proposed a type of gas discharge defined as a gliding arc-microwave hybrid discharge (also called microwave enhanced gliding arc discharge or gliding arc assisted microwave discharge), and experimentally investigated its coordination effects for generating plasma.
The gliding arc acts as an igniter for generating and maintaining microwave plasma at atmospheric pressure, while the microwave-enhanced gliding arc discharge indicates expansion of the length and bulk of plasma flame, which has a positive effect on the residence time and immersion of reactants in the plasma.
The proposed hybrid discharge can be applied to different fields such as chemical synthesis, surface treatment, fuel reforming and environmental improvement as it can generate efficient and bulk plasma with different temperatures and good reaction selectivity at atmospheric pressure.
You can find the details about it in his paper “Coordination effect in generating plasma by gliding arc-microwave hybrid discharge in atmospheric-pressure air” in “Applied Physics Letters” (NI).
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Jo Mar 27, 2026
Austenitic stainless steels are extensively used in a wide variety of industries including the chemical industry due to their good combination of corrosion resistance and weldability.
In high-temperature treatment of stainless steels, M23C6 and chromium carbide are formed along grain boundaries of austenite, causing preferential depletion of Cr along the grain boundary and, consequently, an increased rate of corrosion.
Therefore, many researches have been conducted on the effects of the main factors such as temperature, concentration, microstructure, welding process parameters and pH value on the corrosion characteristics of a 316 L stainless-steel welded joint in different corrosion media. To the best of our knowledge, little research has focused on the investigation of the relationship between the corrosion behaviour and microstructure of a 316 L stainless-steel welded joint in nutrient fertilizer solutions.
In our country, the recent increase in the number of greenhouses for vegetables necessitates production processes of nutrient fertilizer including Ca(NO3)2, KNO3, KH2PO4. Concentrator vessels used in these processes are made of 316 L stainless steel by welding, which requires a great wealth of information concerning the corrosion resistance of the 316 L parent material and weld metal against nutrient fertilizer solutions.
Pang Il Jin, a researcher at the Faculty of Material Science and Technology, quantitatively evaluated the corrosion resistance of 316 L weld metal and parent material, and clearly illustrated their corrosion mechanisms for the methodology of corrosion protection under the service conditions of concentrator vessels.
The test results showed that corrosion potentials of the weld were clearly lower than those of the parent material due to the heterogeneity of the microstructure in the welds.
You can find more information in his paper “A comparative study on corrosion resistance of 316 L stainless-steel welds in nutrient fertilizer solutions such as Ca(NO3)2, KNO3, KH2PO4” in “The Canadian Journal of Chemical Engineering” (SCI).
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Jo Mar 26, 2026
Water is one of the most important natural resources for all living organisms including humans, animals, plants and other organisms. High-quality water is a major factor for human health, environment protection and sustainable development.
There are many WQE methods, and the results from different methods may differ from one another. Therefore, it is necessary to decide which is better.
Yang Won Chol, a researcher at the Faculty of Material Science and Technology, has proposed a novel integrated WQE approach combined with other various WQE methods, and illustrated and compared the effectiveness by applying it to two WQE cases.
First, he developed a novel integrated WQE approach combined with multiple WQE methods based on the weighted membership degree. It consists of the following steps: determining the WQGs of evaluation objects using multiple WQE methods, determining the priority weights of the individual methods, calculating the weighted membership degrees that evaluate objects in every grade/rank, and calculating final WQG indices of objects.
He applied it to two application cases. The results showed that the proposed approach had the maximum correlation and the minimum deviation, compared to other methods, which illustrated the validity of the proposed approach.
For more information, please refer to his paper “A New Integrated Water Quality Evaluation Approach Combined with Different Evaluation Methods Based on Weighted Membership Degree” in “Water Resources Management” (SCI).
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