Jo Jun 28, 2026
The introduction of a self-mixing (SM) displacement sensor into the measurement of mechanical vibration is an effective choice due to the characteristics of the SM interferometry (SMI). This is because the SMI has very favorable advantages for field measurement, for instance, high measurement accuracy, adaptability to any reflective surface, low cost, etc. Moreover, the compactness of SM sensors makes it easy to develop a hand-held portable device.
The key to developing a hand-held SM sensor is how to remove the hand-induced parasitic vibration. Since the removal of parasitic vibration is important for the accuracy of SMI, there have been many studies, divided into hardware-based and software-based methods.
Jang Kum Hyang, a researcher at the Institute of Mirae Industrial Technology, proposed a method of removing the hand-induced parasitic vibration based on data fitting, which is very simple and suitable for a hand-held self-mixing displacement sensor for the measurement of mechanical vibration.
The measurement accuracy that the proposed method provides is less than 30 nm.
If further information is needed, please refer to his paper “Removal of parasitic vibration in a self-mixing measurement for mechanical vibration based on data fitting” in “Applied optics” (SCI).
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Jo Jun 26, 2026
Previous papers suggested an end processing function, an enhanced smooth continuous condition and a method to overcome the defects of the precedent modified analytic embedded atom method (EAM) potentials considering the farther neighbor atoms by fitting model parameters to one or two structure energy differences. The structure energy differences and the binding energy curves as a function of volume calculated by these potentials are better than the calculation results by precedent modified analytic EAM (MAEAM) considering the farther neighbor atoms in the agreement with the experimental results and the Rose equation curves. The original MAEAM proposed only one many-body potential form for body-centered cubic (BCC), facet-centered cubic (FCC) and hexagonal close packed (HCP) metals. So, this potential has been frequently used in the calculation of the properties of metals and alloys. However, as the MAEAM considering farther neighbor atoms suggested different potential forms for different structures, using this potential is inconvenient and the application examples are rare. But it still gives better results than the original MAEAM.
Therefore, it is necessary to adopt a common potential form which can be applied to all kinds of metals such as the original MAEAM, simultaneously considering the farther neighbor atoms.
Ho In Chol, a researcher at the Faculty of Information Science and Technology, suggested a common pair potential form which can be applied to the three kinds of the typical structures of metals and explain the structure stabilities, the structure energy differences and the dependence of binding energies on lattice constants well.
The results by the common-form potentials of the modified EAM for the BCC transition metals Cr, Fe and Mo are in good agreement with experimental data and other calculation results, and significantly better than the precedent potentials for the BCC metals.
For further details, please refer to his paper “Common potential form of modified embedded atom method and BCC transition metals Cr, Fe, and Mo” in “Indian Journal of Physics” (SCI).
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Jo Jun 25, 2026
With the rapid development of nanotechnology, nano-composites with nano-additive agents play an important role in many fields. Nano additive agents take various types and some of them are embedded in the surface of the material to enhance its strength or hardness. Therefore, the studies for understanding the mechanical behavior of nano-inclusions in media are increasing day by day.
The scattering of SH waves was often applied to study the dynamic response around the different kinds of inclusions in the half space. From the preceding investigation results, it can be seen that the studies of the surface/interface effects on the dynamic behavior of inclusions are restricted to the circles. Furthermore, the researches on the effects based on the scattering theory of SH waves have been done much less than others.
Jang Paek San, a researcher at the Institute of Nano Science and Technology, investigated the scattering of SH waves by a semi-circle nano-inclusion embedded in the half space surface using the surface/interface elastic theory.
The numerical simulations showed the following. First, as the size of the inclusion decreases to a nanoscale, the value of DSCF (dynamic stress concentration factor) also decreases, which means that the interface effect tends to suppress the perturbation of the DSCF. Second, when the nano addition agents are added into the surface of a medium, the rigidity of the nano-inclusion should be much smaller than that of the medium. Third, in the case of nanoscale inclusion, the surface/interface effect should be considered.
You can find the details in his paper “Dynamic Stress around a semi-circle nano-inclusion embedded in the half space surface” in “Journal of the Brazilian Society of Mechanical Sciences and Engineering” (SCI).
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Jo Jun 24, 2026
Determination of uranium is very important for effective use of seawater. Uranium is the most stable of all the elements in the ocean. The concentration and pH of uranium in the seawater differ a little according to the region and the depth, but the averages are 3.3×10-6g/L and 8, respectively.
Yun Chol Hun, a researcher at the Institute of Analysis, has reported a new combined method for the determination of trace uranium in seawater.
First, he added ferric chloride to 1L of seawater sample and adjusted the pH to 4. Then, he placed the solution at 80℃ for 30 min to coprecipitate uranium with iron hydroxide. After that, he dissolved the precipitate in nitric acid and electrodeposited it in EMIMBF4 to determine uranium by ICP-OES.
He evaluated the coefficient of diffusion (D) of electrodeposition of U(VI) on platinum electrode in EMIMBF, which was 3.31×10−9cm2/s. The electrochemistry experiments indicated that the reduction of U(VI) at platinum electrode in EMIMBF4 was a quasi-reversible single step two-electron transfer. The percent of chemical coprecipitation recovery of U(VI) was 98.9% and the recovery in electrodeposition was 99.5%.
For more information, please refer to his paper “Determination of uranium in seawater using chemical coprecipitation-ionic liquid electrodeposition by ICP-OES” in “Journal of Radioanalytical and Nuclear Chemistry” (SCI).
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Jo Jun 23, 2026
Flooding is a major hazard in rural and urban areas worldwide and accounts for a large portion of life and economic losses caused by natural disasters. Non-structural measures to reduce flood damage are very economical compared to structural measures.
Accurate and rapid prediction of flood inundation extent is an important task to reduce flood risk. Non-structural measures make it possible to predict inundation areas by combining accurate flood forecast and real-time observations.
Seeded Region Growing (SRG) is widely used for flooded area extraction. The seeded region growing method requires a large amount of memory space because the entire DEM dataset is initially assigned to memory, which cannot be implemented with the existing PC’s memory space. Furthermore, the limited use of computer memory space prevents the implementation of computational continuity during flood inundation analysis. When there is a large area of inundation extent and a large amount of DEM data, many recursive operations required by the seeds region growing algorithm reduce computational efficiency and can cause stack overflow due to the large data. For this reason, the use of seeded region growing algorithm applied to flood inundation prediction is limited.
Ko Song Hwan, a researcher at the Institute of Information Technology, proposed an isosurface region growing method to reduce floodplain extraction time using high resolution DEM, and a locally detailed grid SRG method to solve the problem of different inundation area by different DEM resolutions.
On a contour map with small contour intervals, if all the intersected points on the two adjacent contour lines are submerged, it can be seen that the isosurface between those contours is completely submerged. The isosurface region growing method can reduce the time for flood inundation extent extraction more than the seeded region growing method as it extends inundation areas by isosurface along the contour tree. The locally detailed grid SRG method divides the cells intersecting with top contours of the terrain barrier into small size cells. Then, a seed point is selected on the isosurface which is not completely submerged and the seeded region growing method is applied. This method can solve the problem of distorted diffusion of inundation areas around the terrain barrier.
Comparing the inundation area extraction time by the seed area growth method with that by the contour area growth method and the detailed grid SRG method, he found that the proposed method consumes less computation time.
His paper “Flood inundation extent extraction using isosurface region growing and locally detailed grid SRG” was presented at “2025 10th International Conference on Intelligent Information Technology (ICIIT 2025)”.
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Jo Jun 22, 2026
Moving packed bed drying can reduce the costs of transportation and storage of products. Grain dryers can be categorized into fixed bed dryers, fluidized bed dryers, rotary kilns and moving bed dryers.
A packed moving bed dryer using the air of low temperature (100℃) was developed in order to get large amounts of grain with required moisture in a given time.
Jon Chol Jin, a section head at the Faculty of Thermal Engineering, has proposed a steady moisture equation for analysing a grain drying process at a packed moving bed, and carried out a numerical simulation based on the governing equations of the grain energy equation.
The simulation results showed that the grain moisture grows lower when the moving velocity of the packed bed becomes lower.
The present model can be applied to predicting the positional distribution of physical quantities such as temperatures of air and grains as well as the relative humidity of air and the moisture content of grains in an arbitrarily-shaped packed moving grain dryer.
For further details, please refer to his paper “Steady State Analysis for Heat and Mass Transfer of Moving Grain in Cylindrical Dryer” in “Proceedings of KUTIC-2025”.
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