Jo Dec 7, 2021
Kim Kon, researcher from Faculty of Applied Chemical Engineering studied and introduced gas-saving heat radiation fire-grate with our own raw materials, which is useful to reduce food processing time and save gas by promoting combustion and thermal efficiency.
He designed the most appropriate structure of heat radiation fire-grate to apply it to various kinds of gas cooker, and put the synthesizing method, materials and thermodynamic characteristics etc. on a scientific basis.
Flame temperature of heat radiation fire-grate is 70~120℃ higher than those of general cast fire-grates, flame color is orange and thermal efficiency is more than 75%.
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Jo Nov 24, 2021
Although semiconductor capacitive pressure sensor is more sensible and less affected by temperature than resistance pressure sensor and thus more often used in pressure measurement in harsh situations, it has the disadvantage due to the nonlinearity of output characteristic. Therefore, in order to improve this nonlinearity, previous studies proposed various complex forms of electrode structures including double electrode, step electrode, complex electrode. However, these generate several difficult problems in device manufacturing process. Also, many assumptions were needed in mathematical analysis of operation characteristic of device due to the complexity in structure and an exact prediction about the operation characteristic was difficult because the error of analytic model is large.
For the enhancement of overload protection capacity and linearity as well as the sensitivity of device, the structure of capacitive pressure sensor operating in the contact mode is proposed and the structure of electrode is designed in the form of curved surfaces, with which micro-machining is possible, on the basis of MEMS technology, which is developing rapidly throughout the world. In this case, the simple structure leads to simple manufacturing process and lower cost.
The virtual radius model, the analytic model used to analyze contact deformation characteristic in previous studies, correspond to the case in which the electrode is plane and the curved surface electrode and contact deformation characteristic of diaphragm cannot be interpreted with this model.
New mathematical model, which is able to interpret the curved surface electrode and the contact deformation characteristic of diaphragm, was proposed on the basis of previous virtual radius model.
Also, the contact deformation characteristic of diaphragm depending on pressure in concave well substrate touch-mode capacitive pressure sensor is interpreted with the new analytic model and on the basis of it, the response characteristic of sensor was interpreted. The correctness of proposed analytic model and the result of interpretation are tested through simulation using finite element interpreter.
The proposed analytic model is new and esteemed to be useful to design various types of capacitive pressure sensor and to predict and estimate the characteristics of them in the future.
This paper is published by Kang Myong Chol, section leader from Semiconductor Institute on the title of “Capacitance response of concave well substrate touch-mode capacitive pressure sensor: mathematical analysis and simulation” in the SCI magazine, “Microelectronics Journal”.
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Jo Nov 23, 2021
Choe Chol Min, section leader from Faculty of Materials Science and Technology manufactured centrifugal compressor impeller using FDM and investment casting.
Centrifugal compressor impeller, which enables to enhance engine output and combustion efficiency, is very difficult to manufacture as it’s very thin and propene is twisted.
He proposed a new method for manufacturing centrifugal compressor impeller using FDM and investment casting, and a scientific method for raising the extraction rate in casting up to more than 90% by fixing reasonable indices of investment casting process based on the optimal indices of FDM process and simulation analysis.
His paper titled “Manufacture of centrifugal compressor impeller using FDM and investment casting” is published in the SCI magazine, “International Journal of Advanced Manufacturing Technology”.
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Jo Nov 16, 2021
National Scientific and Technological Exhibition on Nano Technology Section-2021 was held between October 22 and 29 under the sponsorship of the Central Committee of Korean Federation of Science and Technology.
This exhibition was held under the theme of “Strengthening the foundation for the establishment of nano industry”, drawing teachers, researchers, graduate school students etc. from dozens of institutions including
The exhibition went on divided into scientific and technological exhibition and scientific and technological forum in the form of screen meeting.
“Ozone Generating System using Nano Composite Material”, the research work of Kim Kwang Jun, researcher from Nano Physics Engineering Institute was esteemed to win the first place in the exhibition and “Relationship between Relative Humidity and Inductive Capacity in Nano Porosity Material”, the proposal from Researcher Kong Myong Nam got the first place in the public discussion.
Besides, research works and proposals from many researchers of the Institute including Ha Chol Ho, Cha Su Song, Jang Tae Il, Ro Myong Gum, Mun Yong Su, Mun Se Hyon etc. got placing in the ranking and so Nano Physics Engineering Institute held the first place in the team ranking of the Exhibition.
Also, proposals from many teachers and researchers from Faculty of Materials Science and technology, Faculty of Applied Chemical Engineering, General Assay Office etc. were esteemed superior.
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Jo Nov 15, 2021
National Public Presentation Meeting of Welding Science and Technology was held between October 12 to 15 under the sponsorship of the Central Committee of Korean Federation of Science and Technology.
The public discussion was held in the form of screen meeting. Teachers, researchers, graduate school students, field technicians and Three-revolution team members from over ten institutions including our University, Pyongyang University of Architecture, Pyongyang University of Mechanical engineering, Pyongyang University of Transport, Welding Research Institute of National Academy of Science.
In this forum, several proposals such as those suggested by Cha Kwang Jin, section leader from the Faculty of Materials Science and Technology –“Inverter CO2 shielded gas semi-automatic arc welding equipment” and graduate school student Pak Kwang Jin –“Arc spray process of cool punching die” were highly appreciated as for making success in the research work on new welding methods and localizing equipment, raw materials and resources for welding field.
Besides, several proposals from by our university were estimated valuable.
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Jo Nov 14, 2021
The research group led by Jang Song Ok, laboratory head at the Faculty of Mining Engineering succeeded in manufacturing a natural graphite brush for shaft grounding and is trying to make further achievements in their research.
They proved scientifically that it is possible to make a brush for shaft grounding with natural graphite and decided the structure, quality and operation system of the material for the brush with high capacity of electro motion and contact property and with improved wear property.
The permissible current density of the brush is 20~30A/㎠, the ratio of wear is about 0.3㎜/1 000㎞ and the spring pressure is around 20㎪.
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