Jo May 26, 2026
Inorganic nanoparticles have been dispersed in resin blends to prepare many nano-composite resin materials. This hybrid material exhibits the combined properties of inorganic nanoparticles such as mechanical strength, elasticity and thermal stability, and of the processibility and flexibility of organic polymers.
Previous studies reported that the addition of SiO2 nanoparticles to PVC resin leads to enhanced sound resistance, and adding TiO2 nanoparticles to PVC resin can enhance its whiteness and prevent UV degradation of resin products. However, there are very few polymer materials with both SiO2 and TiO2 nanoparticles.
Addition of SiO2 and TiO2 nanoparticles together to the PVC resin will result in its lower degradation of by UV light and better resistance to degradation than adding either of them alone.
For the purpose of using PVC nano-composite as a raw material instead of rubber that is often used as a conveying belt material, Jang Un Hui, a researcher at the Institute of Analysis, prepared new nano-composites by mixing SiO2 and TiO2 nanoparticles with PVC resin, and carried out differential scanning calorimetry (DSC) under non-isothermal conditions in order to investigate the crystallization behavior and kinetics of the newly prepared PVC/Nano SiO2-TiO2 composites.
The analysis results showed that the crystallization behavior of PVC/Nano SiO2-TiO2 composite with 3-5% SiO2 and TiO2 nanoparticles is good.
For more information, please refer to her paper “Study on the non-isothermal crystallization kinetics of PVC/NanoSiO2-TiO2 composite resin by DSC” in “Journal of Polymer Research” (SCI).
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Jo May 25, 2026
The FFC method has been widely used to prepare metal powders and alloy powders from their oxides in molten salts.
Many researchers have employed several electrochemical techniques to study proper mechanisms and experimental conditions for it.
However, there have been no studies reported on the method of preparing Dy-Fe alloy powders from Dy2O3-Fe2O3 mixtures in molten CaCl2 by the FFC method.
Kim Pyong Hun, a section head at the Institute of Analysis, has conducted a study to prepare Dy-Fe alloy powders from Dy2O3-Fe2O3 mixtures in molten CaCl2 by the FFC method.
In the Dy2O3-Fe2O3 mixtures for his study, the ratio of Dy to Fe was 1:2. He used the cyclic voltammetry and constant voltage electrolysis.
Three cathodic current peaks were observed in the cyclic voltammetric curves, which explains that the reduction mechanism of Dy2O3–Fe2O3 mixtures goes through several steps.
The suitable electrolysis conditions for the preparation of alloy DyFe2 from Dy2O3–Fe2O3 mixtures in molten CaCl2 were 2.8 V, 850 ℃ and 20 h.
You can find more information in his paper “Preparation of Dy-Fe Alloy Powders from Dy2O3–Fe2O3 Mixtures in Molten CaCl2 by FFC Method” in “Transactions of the Indian Institute of Metals” (SCI).
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Jo May 24, 2026
Whenever new viruses came into being, mankind has acquired various knowledge including their nature and transmission, and the symptoms and treatment of the diseases, and made vaccines and established treatment tactics.
One of the important issues to cope with infectious diseases is prediction of virus transmission by mathematical modeling. Based on mathematical modeling, it has been widely studied in the world. Mathematical modeling for predicting future epidemics makes it possible to predict the number of medical personnel and beds, medical equipment, medical drug supplies, etc. that are needed to prepare at hospitals. It also helps find a suitable approach for medical service through simulations.
The parameters included in this mathematical model are the key elements that characterize the epidemic of diseases. Therefore, it is important to set the parameters realistically.
Kim Ju Hyong, a researcher at the Faculty of Biomedical Engineering, proposed a method for determining the parameters involved in mathematical models of epidemics using genetic algorithms, and verified its validity.
To test the validity of this method, he built a SEIHRD model and compared the accuracy of the simulation with unknown parameters determined when the underlying data were prepared in various forms.
The results show that the proposed method is a recursive one for simply determining unknown parameters in a mathematical model study considering the spread of epidemics.
For more information, please refer to his paper “A method to determine the unknown parameters of mathematical model of epidemic transmission by genetic algorithm” in “Network Modeling Analysis in Health Informatics and Bioinformatics” (SCI).
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Jo May 22, 2026
Bio-identification by deep neural networks in such devices with limited computational power and memory capacity as mobile phones has become an essential but challenging task today. As faces have rather invariable features among human biometric features, face recognition is considered as the most important biometric identification task. Face recognition has been widely used for user authentication in security systems such as electronic payment systems as it can identify faces from facial images from photographs or videos, and it has been studied for years.
The face recognition system using convolutional neural networks is considered as the best method among the existing ones. Face recognition network models that have been developed recently and have proved to be superior in performance cannot be used for real-time face recognition in devices with limited computational resources such as low base computers or mobile phones because their structure is very complex and they need a large amount of computation. What is more, reducing the number of layers continuously to reduce computational burden affects recognition performance.
In previous studies, several methods to improve the trade-off between speed and recognition performance were proposed. One of them is GhostFaceNets which uses Ghost module to reduce the feature map redundancy, where the trade-off between speed and recognition performance is improved by extracting less repetitive feature maps with small amount of computation. In GhostFaceNets, they improved the trade-off between speed and accuracy by performing the attention operation using a DFC (decoupled fully-connected) attention. However, the DFC attention has limitations in capturing wide spatial information, which may lead to the degradation of recognition performance.
Jo Kwang Chol, a researcher at the Institute of Information Technology, has designed a network structure with low computational cost and improved performance by combining the self-attention module with the extended Ghost module based on the backbone of GhostFaceNets, and verified its accuracy using international standard databases.
The results showed that the proposed network model brings significant improvement in face recognition performance with 99.74% in LFW and 97.7% in AgeDB-30 and that with 42 MFLOP, it can support stable real-time face recognition in embedded devices.
For more details, you can refer to his paper “GhostFormerNet: A Lightweight Face Recognition Method based on Extended Ghost Module and Self-Attention” in “2025 International Conference on Graphics and Signal Processing” (EI).
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Jo May 21, 2026
Rare earth minerals including pyrochlore contain uranium, thorium and rare earths, and the processing of these rare earth ores must result in a mixed solution containing uranium, thorium and rare earths.
Many studies have been carried out to determine the concentration of individual components in the mixtures of uranium, thorium and rare earth, and thus, various instrumental methods have been widely used. However, these methods have disadvantages such as the need for special analytical tools, the need for sample solidification and the high cost of analysers concerned.
Due to the similar spectroscopic properties of uranium, thorium and rare earths, some analytical methods have been developed to separate uranium, thorium and rare earths and determine the concentration of individual components using various separation methods including extraction and ion exchange. However, these methods have other disadvantages such as long analysis time and complicated operation.
Kwon Myong Gang, a researcher at the Institute of Analysis, has investigated analytical methods for simultaneously determining individual components in a mixture of uranium, thorium and cerium obtained during the pyrochlore hydrometallurgical process, using spectrophotometric methods.
First, he proved that the maximum absorption wavelengths of uranium, thorium and cerium in three different solutions (3, 0.1mol/L HCl, 1mol/L CH3COOH) were 660, 652 and 660nm, respectively. Then, he used the relationship between the concentration of individual components and the absorbance to determine the absorption coefficients of individual components in different solutions. After that, based on the principle of absorbance additivity, he established a simulation equation between absorbance and concentration and used it to determine the concentration of individual components in the mixture solution. The concentration limit within which the additivity of absorbance in the mixed solution is established was less than 2mg/L of uranium and cerium, and 1.5mg/L of thorium. The error of analysis was less than 3%.
For further details, you can refer to his paper “Simultaneous Spectrophotometric Analysis of Uranium, Thorium, Cerium During Pyrochlore Hydrometallurgical Process” in “Proceedings of KUTIC-2025”.
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Jo May 20, 2026
At present, in rare earth production, double salt precipitation is widely used for separation of rare and non-rare earth elements, and separation of quaternary cerium and trivalent rare earth elements. Rare earth double sulphates are commonly treated by hydroxide, but the filtration is difficult because the rare earth hydroxide obtained during the hydroxide conversion is an amorphous precipitate. In contrast, if RE double sulphates are converted into carbonates, filtration and dissolution by acids become easier because RE carbonates are crystalline precipitates.
Ri Sun Chol, a researcher at the Faculty of Chemistry, conducted a study to convert rare earth double sulphates obtained from monazite sulphate leachates to rare earth carbonates using sodium carbonate.
Aiming to improve the conversion of rare earths and to effectively separate U and Th from RE carbonates, he investigated the influence of reaction parameters using Taguchi-Grey Relation Analysis (Taguchi-GRA), determined the optimum conditions and studied the separation of U and Th.
When reaction temperature is 80℃, reaction time 2h, additive amount of sodium carbonate 1.5 times the theoretical amount, the ratio of solid to liquid 2:1 and stirring speed 200r/min, the RE carbonate conversion was 97.1% and the U and thorium removal 80.8% and 0.3%, respectively.
For more information, please refer to his paper “Study on the Carbonate Conversion of Rare Earth Double Sulfates” in “Proceedings of KUTIC-2025”.
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