Jo Aug 16, 2021
Researcher Hong Myong Son at Faculty of Materials Science and Technology and his research group succeeded in producing non-magnetic hard alloy which contains no cobalt with domestically available raw materials. This kind of alloy is used as the basic material of molding tools and is urgently needed in the various sectors of the national economy.
The hardness of this alloy is more than HRA 91, the bending strength more than 1.8GPa and the saturation magnetization strength less than 3Gs.
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Jo Aug 9, 2021
Pak Se Yang, a researcher at Science Engineering Institute, reported a paper “Data-driven Robust Controller Design by Geometric Constraints in Frequency-Domain” in SCI magazine "International Journal of Dynamics and Control".
In the paper, he found that the representation of the performance factor of the Robust controller with geometric limit in frequency domain has a drawback of disagreement between the control ability and design characteristics due to the strict assumption and large error, and proposed a new method to enhance the control ability by improving geometric limit.
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Jo Aug 4, 2021
The research team led by Kim Ryul, a researcher at the Faculty of Electrical Engineering, has developed metallic oxide lightning arrester for high voltage based on the domestic resources, thus contributing to the regular operation of electric equipment.
The non-interval metallic oxide lightning arrester is made by sintering the mixture of zinc oxide and other oxides such as arsenic oxide, aluminium oxide at over 1 150℃. The voltage degree of nonlinear resistance of the metallic oxide lightning arrester is over 318V/mm.
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Jo Jul 15, 2021
Pak Se Yang, a researcher at Science Engineering Institute, reported a paper “Senseless vector control of PMSM with parameter error compensation” in SCI magazine "International transactions on Electrical Energy System"31(5).
In the paper, he carefully analyzed the drawback of preceding studies that error compensation algorithm is rather complicated and inefficient.
Based on it, he proposed a new method for enhancing the estimation and control correctness by estimating the current value based on motor model and compensating the element made by parameter error separately in the error compared with measured value.
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Jo Jul 14, 2021
Yang Won Chol, a researcher at the Faculty of Materials Science and Technology, reported a paper “A quantitative and intuitive materials selection MADM method based on quadrant circular constellation graph” in the SCI magazine "Proc IMechE Part L: Journal of Materials: Design and Applications".
In the paper, he found the drawback of the traditional semi-circular constellation graph and proposed a new quadrant circular constellation graph. Based on the idea of possibility for applying it to intuitive representation of multi-criteria decision-making (MCDA), he proposed a new quantitative and intuitive materials selection MADM method based on quadrant circular constellation graph.
He made it possible to select material in a quantitative and intuitive way by representing the ability of materials not only in a quantitative way but also in an intuitive way on a 2D plane.
The proposed method, which is applied to select the best magnesium alloy material for automotive wheels and is proved to be effective by comparing with preceding methods, proposed a new quantitative and intuitive method and tool for material selection problems arising in reality, thus experts estimated that the method is very interesting and can be of a new contribution to its field.
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Jo Jul 7, 2021
The research group including Kim Ryul, a researcher in the Faculty of Electrical Engineering contributed to the development of ultra high voltage suspension insulator based on the domestic resources.
It is proved that the newly developed plastic alumina insulator can be used as ultra high voltage suspension insulator, with its insulation property fully assured and all the characteristic features such as bending strength, tensile strength and thermal break down temperature much higher than feldspar insulator which is currently being used.
The bending strength is over 160MPa and tensile strength over 55MPa and thermal break down temperature over 182℃.
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