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Wyszukujesz frazę "Kim, Ju-Yong" wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Fabrication of Metal Gas Filter by Material Extrusion Additive Manufacturing Process
Autorzy:
Yi, Yu-Jeong
Lee, Min-Jeong
Yun, Su-Jin
Park, Manho
Kim, Ju-Yong
Lee, Jungwoo
Yun, Jung-Yeul
Powiązania:
https://bibliotekanauki.pl/articles/2174560.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas filter
additive manufacturing
stainless steel
porosity
powder size
Opis:
Recently, 3D printing processes have been used to manufacture metal powder filters with manufacturing complex-shape. In this study, metal powder filters of various shapes were manufactured using the metal extrusion additive manufacturing (MEAM) process, which is used to manufacture three-dimensional structures by extruding a filament consisting of a metal powder and a binder. Firstly, filaments were prepared by appropriately mixing SUS316 powder with sizes ranging from 7.5 µm to 50 µm and a binder. These filaments were extruded at temperatures of 100℃ to 160℃ depending on the type of filament being manufactured, to form three types of cylindrical filter. Specimens were sintered in a high vacuum atmosphere furnace at 850℃ to 1050℃ for 1 hour after debinding. The specimens were analyzed for permeability using a capillary flow porometer, porosity was determined by applying Archimedes’ law and microstructure was observed using SEM.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1517--1520
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on North Korea’s Education-Centering for Middle School
Autorzy:
Eun-Jung, Kim
Ju-Cheol, Shin
Yong-Deog, Kim
Powiązania:
https://bibliotekanauki.pl/articles/2028735.pdf
Data publikacji:
2014-03-31
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
education
North Korea’s middle school
interview
North Korean defectors
developed communist
Opis:
This paper deals with the reality of North Korea’s education and its middle school education. North Korea still maintains its own curtain and remains isolated from the rest of the world. For that reason, it is very difficult for an individual researcher to get closer to the reality of North Korea’s education. To overcome the limitation, this article actively utilizes a means- interview with defectors who live in South Korea. To understand the current situation of North Korean education, the author interviewed 38 students. It is very useful in order to know the reality that cannot be accessed in the official way. This article firstly examines the general goals of North Korean education and the characteristics of the school curriculum. Next, this paper describes the features of North Korea’s middle school students’ life. Through examining the educational situation of North Korea, the principles of North Korean education have been revealed as fostering newly developed communists. Furthermore, it is a principle that the texts included in North Korea’s national language textbooks should stick to the communist partisanship and reflect socialist patriotism.
Źródło:
The New Educational Review; 2014, 35; 151-162
1732-6729
Pojawia się w:
The New Educational Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Deformation Temperature on the Magnetic Properties of PrFeB Alloy Fabricated by Gas Atomization
Autorzy:
Cho, Ju-Young
Song, Myung-Suk
Choa, Yong-Ho
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/2049154.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PrFeB alloy
gas atomization
plastic deformation
rolling
REFeB magnet
Opis:
To form the fine micro-structures, the Pr17Fe78B5 magnet powders were produced in the optimized gas atomization conditions and it was investigated that the formation of the textures, microstructures, and the changes in the magnetic properties with increasing the deformation temperatures and rolling directions. Due to the rapid cooling system than the casting process, the homogenous microstructures were composed of the Pr-rich and Pr2Fe14B without any oxides and α-Fe and enables grain refinement. The pore ratios were 2.87, 1.42, and 0.22% at the deformation temperatures of 600, 700, 800°C, respectively in the rolled samples to align the c-axis which is the magnetic easy axis. Because Pr-rich phase cannot flow into the pore with a liquid state at low temperature, the improvement of pore densification was gradually observed with increasing deformation temperature. To confirm the magnetic decoupling effects of Pr2Fe14B phases by Pr-rich phases, the magnetic properties were investigated in rolled samples produced at the deformation temperature of 800°C. Although the remanent field is slightly decreased by 30%, the coercivity fields increased by about 2 times than that previous casted ingot. It is suggested that the gas atomization method can be suitable for fabricating grain refined and pure PrFeB magnets, and the plastic deformation conditions and rolling directions are a critical role to manipulate microstructure and magnetic properties.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 955-958
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Powder Size on the Microstructure and Magnetic Properties of Nd-Fe-B Magnet Alloy
Autorzy:
Cho, Ju-Young
Abbas, Sardar Farhat
Choa, Yong-Ho
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/353634.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B
gas atomization
powder size
crystal orientation
hot deformation
Opis:
Rare earth Nd-Fe-B, a widely used magnet composition, was synthesized in a shape of powders using gas atomization, a rapid solidification based process. The microstructure and properties were investigated in accordance with solidification rate and densification. Detailed microstructural characterization was performed by using scanning electron microscope (SEM) and the structural properties were measured by using X-ray diffraction. Iron in the form of α-Fe phase was observed in powder of about 30 μm. It was expected that fraction of Nd2 Fe14 B phase increased rapidly with decrease in powder size, on the other hand that of α-Fe phase was decreased. Nd-rich phase diffused from grain boundary to particle boundary after hot deformation due to capillary action. The coercivity of the alloy decreased with increase in powder size. After hot deformation, Nd2 Fe14 B phase tend to align to c-axis.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 623-626
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Temperature on the Plastic Deformability of Gas Atomized NdFeB Anisotropic Magnets
Autorzy:
Cho, Ju-Young
Choa, Yong-Ho
Nam, Sun-Woo
Rasheed, Mohammad Zarar
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/351923.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
NdFeB permanent magnet
stoichiometric composition
gas atomization
plastic deformability
crystal orientation
Opis:
NdFeB anisotropic sintered permanent magnets are typically fabricated by strip casting or melt spinning. In this study, the plastic deformability of an NdFeB alloy was investigated to study the possibility of fabricating anisotropic sintered magnets using gas atomized powders. The results show that the stoichiometric composition Nd12Fe82B6 softens at high temperatures. The aspect ratio and orientation factor of Nd12Fe82B6 billets after plastic deformation were found to increase with increasing plastic deformation temperature, particularly above 800°C. This confirms that softening at high temperatures can lead to plastic deformation of Nd2Fe14B hard magnetic phases.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1293-1296
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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