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 Apr 1, 2026
Swinging, one of the folk games enjoyed by the Korean women from olden times, has been conducted on folk holidays in spring and autumn.
Swinging had different names in different areas: kuli, kulgi, hulgi, kunggu, kundi and chuchon. In those days, swing ropes were fixed to the branches of shade trees and there was a footboard between the ropes for easy standing. Safety wristbands made of soft cloth were tied to the ropes so that people on the swing could propel themselves vigorously without anxiety in order to reach the bell.
Swinging was classified into single swinging (one person on the swing) and pair swinging (two people face to face on the swing). Single swinging was often preferred for a match.
Win and defeat was decided in several ways. At first, as the ropes were fixed to the thick boughs, kicking or catching in one’s mouth the twigs or sprigs set as a target in the front, or measuring the maximum height of the bell attached to the holder by elevating it were common. After that, a measuring tape with scales attached to the bottom of the footboard was used to decide winners by reading the marks at the swing holder.
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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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Jo Mar 25, 2026
Since high carbon steel has high tensile strength and hardness and good wear resistance, and is cheaper than alloy steels, it has been widely used for manufacturing cutting tools, formers, springs, rails, etc. However, it is recommended to avoid welding of high carbon steel with poor weldability as much as possible because the weld zones of this steel can be easily cracked by high hardenability.
Nevertheless, there are many cases in practice that need inevitable welding. Especially, welding high carbon steel with good wear resistance and high impact strength such as 75Mn steel is one of the challenges in practice: butt-joint welding of track rails of 75Mn steel, for example.
Various welding methods were used to join high carbon steel such as rails, and in these methods, enough preheating and post-weld heat treatment were performed in order to prevent cracking. However, there may be cases where preheating or post-heating cannot be applied but should be avoided. If preheating and post-weld heat treatment of welding zones are not conducted, additional oxidation and deformation of weld zones can be prevented and welding costs can be saved.
Jon Yong Il, a researcher at the Faculty of Material Science and Technology, investigated an arc welding process for a long butt joint of high carbon 75Mn steel plates without preheating to ensure the quality of weld and high productivity.
The analysis of microstructures and mechanical properties of weld showed that the metal inert gas (MIG) welding process is a dominant one among various welding methods.
You can find the details in his paper “Application possibility of arc welding processes for long butt joint of 75Mn steel plates without preheating” in “The Journal of Engineering” (SCI).
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