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Wyświetlanie 1-14 z 14
Tytuł:
Comparative Study on the Electrical and Mechanical Characteristics of Ni-30wt%Co and Cu-2wt%Be Alloy for Development of Semiconductor Test Probe Pin
Autorzy:
Park, Jin-Young
Kim, Young-Choon
Kim, Jae-Gyun
Powiązania:
https://bibliotekanauki.pl/articles/353264.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
probe pin
Be-Cu Alloy
Ni-Co Alloy
test socket
mechanical properties
electrical properties
Opis:
Ultra-precision testing is a very important procedure to secure the reliability of the products as well as for the technology development in the areas of semiconductor and display. Accordingly, companies manufacturing equipment for testing of semiconductor and display have been continuously executing researches for the improvement of the performances of test sockets used in test equipment. Through this study, characteristics of the materials in accordance with the mechanical and electrical properties of Ni-30wt%Co alloy and newly developed Cu-2wt%Be alloy were analyzed in order to select the probe pin material of the socket, which is a key component used in the semiconductor testing equipment. In addition, finite element interpretation was executed by using Ansys Workbench 14.0 to comparatively analyze the finite element interpretation results and experimental results. Experiment was executed for the mechanical properties including tensile strength, elasticity modulus, specific heat, thermal expansion coefficient and Contact Force, for electrical properties, experiment on surface resistance, specific resistance and electrical conductivity was executed to measure the properties. It was confirmed that the results of finite element interpretation and experiment displayed similar trend and it is deemed that the Contact Force value was superior for Be-Co alloy. Through this study, it was confirmed that the newly developed Be-Co alloy is more appropriate as probe pin material used as the core component of test socket used in the semiconductor testing equipment than the existing Ni-Co alloy.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 943-947
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural, Electrical, and Optical Properties of ZnO Films Grown by Atomic Layer Deposition at Low Temperature
Autorzy:
Park, Ji-Young
Weon, Ye Bin
Jung, Myeong Jun
Choi, Byung Joon
Powiązania:
https://bibliotekanauki.pl/articles/2174578.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
zinc oxide
ZnO
atomic layer deposition
low temperature growth
optoelectronic properties
Opis:
Zinc oxide (ZnO) is a prominent n-type semiconductor material used in optoelectronic devices owing to the wide bandgap and transparency. The low-temperature growth of ZnO thin films expands diverse applications, such as growth on glass and organic materials, and it is also cost effective. However, the optical and electrical properties of ZnO films grown at low temperatures may be inferior owing to their low crystallinity and impurities. In this study, ZnO thin films were prepared by atomic layer deposition on SiO2 and glass substrates in the temperature range of 46-141℃. All films had a hexagonal würtzite structure. The carrier concentration and electrical conductivity were also investigated. The low-temperature grown films showed similar carrier concentration (a few 1019 cm-3 at 141°C), but possessed lower electrical conductivity compared to high-temperature (>200°C) grown films. The optical transmittance of 20 nm thin ZnO film reached approximately 90% under visible light irradiation. Additionally, bandgap energies in the range of 3.23-3.28 eV were determined from the Tauc plot. Overall, the optical properties were comparable to those of ZnO films grown at high temperature.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1503--1506
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of Microwave Absorption Characteristics by Coating Layer in Substituted U-Type Ferrites
Autorzy:
Jeong, Kwang-Pil
Kim, Jeong-Gon
Yang, Su-Won
Choi, Jin-Hyuk
Park, Seung-Young
Powiązania:
https://bibliotekanauki.pl/articles/353196.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hexagonal ferrite
U-type ferrite
silicon oxide layer
microwave absorption
Opis:
The U-type ferrite is a kind of hexagonal ferrite, and it is known as a microwave absorber in the X-band. The magnetic and dielectric loss of the U-type ferrite change to the composition and coating layer, etc. In this study, the silicon oxide layer was coated on the substituted U-type ferrites to improve microwave absorption characteristics. The complex permittivity and complex permeability were measured using toroidal specimens that were press-molded and the measured frequency range was set from 2-18 GHz. The improvement of the microwave absorption rate was different according to the type of the substituted U-type ferrites. Only in the substituted U-type ferrites with nickel and zinc, an improvement in the microwave absorption rate due to enhancement of magnetic loss was confirmed. The highest microwave absorption was 99.9% at 9.6 GHz, which was S_Z0.5 U.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1287-1291
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Milling Duration on the Thermoelectric Properties of n-Type Bi2Te2.7Se0.3
Autorzy:
Park, Min-Soo
Koo, Hye-Young
Park, Yonh-Ho
Ha, Gook-Hyun
Powiązania:
https://bibliotekanauki.pl/articles/354698.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermoelectric
bismuth telluride
powder
milling
Opis:
In this study, an oxide reduction process and a reduction-sintering process were employed to synthesize a thermoelectric alloy from three thermoelectric composite oxide powders, and the thermoelectric properties were investigated as a function of the milling duration. Fine grain sizes were analyzed by via X-ray diffraction and scanning electron microscopy, to investigate the influence of the milling duration on the synthesized samples. It was found that microstructural changes, the Seebeck coefficient, and the electrical resistivity of the compounds were highly dependent on the sample milling duration. Additionally, the carrier concentration considerably increased in the samples milled for 6 h; this was attributed to the formation of antisite defects introduced by the accumulated thermal energy. Moreover, the highest value of ZT (=1.05) was achieved at 373K by the 6-h milled samples. The temperature at which the ZT value maximized varied according to the milling duration, which implies that the milling duration of the three thermoelectric composite oxide powders should be carefully optimized for their effective application.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 591-595
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology Control of One-Dimensional Gallium Nitride Nanostructures by Modulating the Crystallinity of Sacrificial Gallium Oxide Templates
Autorzy:
Ko, Yun Taek
Park, Mijeong
Park, Jingyeong
Moon, Jaeyun
Choa, Yong-Ho
Lee, Young-In
Powiązania:
https://bibliotekanauki.pl/articles/2049246.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
GaN
nanofiber
nanotube
electrospinning
chemical transformation
Opis:
In this study, we demonstrated a method of controllably synthesizing one-dimensional nanostructures having a dense or a hollow structure using fibrous sacrificial templates with tunable crystallinity. The fibrous Ga2O3 templates were prepared by calcining the polymer/gallium precursor nanofiber synthesized by an electrospinning process, and their crystallinity was varied by controlling the calcination temperature from 500°C to 900°C. GaN nanostructures were transformed by nitriding the Ga2O3 nanofibers using NH3 gas. All of the transformed GaN nanostructures maintained a one-dimensional structure well and exhibited a diameter of about 50 nm, but their morphology was clearly distinguished according to the crystallinity of the templates. When the templates having a relatively low crystallinity were used, the transformed GaN showed a hollow nanostructure, and as the crystallinity increased, GaN was converted into a denser nanostructure. This morphological difference can be explained as being caused by the difference in the diffusion rate of Ga depending on the crystallinity of Ga2O3 during the conversion from Ga2O3 to GaN. It is expected that this technique will make possible the tubular nanostructure synthesis of nitride functional nanomaterials.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 709-712
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Adding Niobium and Vanadium to Fe-Based Oxide Dispersion Strengthened Alloy
Autorzy:
Park, Chun Woong
Choi, Won June
Byun, Jong Min
Kim, Young Do
Powiązania:
https://bibliotekanauki.pl/articles/353024.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-based ODS
vanadium
niobium
superalloy
hardness
Opis:
In this study, the effects of adding niobium and vanadium to Fe-based oxide dispersion strengthened alloys are confirmed. The composition of alloys are Fe-20Cr-1Al-0.5Ti-0.5Y2 O3 and Fe-20Cr-1Al-0.5Ti-0.3V-0.2Nb-0.5Y2 O3. The alloy powders are manufactured by using a planetary mill, and these powders are molded by using a magnetic pulsed compaction. Thereafter, the powders are sintered in a tube furnace to obtain sintered specimens. The added elements exist in the form of a solid solution in the Fe matrix and suppress the grain growth. These results are confirmed via X-ray diffraction and scanning electron microscopy analyses of the phase and microstructure of alloys. In addition, it was confirmed that the addition of elements, improved the hardness property of Fe-based oxide dispersion strengthened alloys.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1265-1268
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laser Cladding of WC/T-800 Cermet: Fabrication, Microstructure and Wear Properties
Autorzy:
Kim, Kyoung-Wook
Kim, Young-Kyun
Park, Sun-Hong
Lee, Kee-Ahn
Powiązania:
https://bibliotekanauki.pl/articles/2049250.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CoMoCr alloy
WC
cermet
laser cladding
microstructure
wear properties
Opis:
This study fabricated a WC/T-800 cermet coating layer with Co-Mo-Cr (T-800) powder and WC powder using laser cladding, and analyzed its microstructure, hardness and wear properties. For comparison, casted bulk T-800 was used. Laser cladded WC/T-800 cermet coating layer showed circular WC phases in the Co matrix, and dendritic laves phases. The average laves phase size in the cermet coating layer and bulk T-800 measured as 7.9 µm and 60.6 µm, respectively, indicating that the cermet coating layer had a relatively finer laves phase. Upon conducting a wear test, the cermet coating layer added with WC showed better wear resistance. In the case of laser cladded WC/T-800 cermet coating layer, abrasion wear was observed; on the contrary, the bulk T-800 showed pulled out laves phases. Based on the above findings, the WC/T-800 cermet coating layer using laser cladding and the relationship between its microstructure and wear behavior were discussed.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 713-717
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Microstructure and Mechanical Properties of Al 3003 Alloy Weld by Stationary Shoulder Friction Stir Welding Process
Autorzy:
Jung, Woo-Chul
Park, Joo-Heon
Yoon, Sang-Min
Kim, Young Kyun
Powiązania:
https://bibliotekanauki.pl/articles/2203728.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stationary shoulder friction stir welding
aluminum 3003 alloy
microstructure
mechanical properties
Opis:
The lap joint welding of Al 3003 alloy by stationary shoulder friction stir welding (SSFSW) was performed under the conditions of tool rotation and welding speed, and it was confirmed that the welding was performed under all conditions. The tunnel defects and pores were formed in the weld zone at the lowest tool rotation and welding speed, and it is increased, the weld surface has been improved. At the same tool rotation speed at the welding speed is increased, the grain size was refined in the stir zone (SZ) and thus the hardness increased by about 14% compared to the base metal. The tensile shear strength is measured to be 10 kN or more under most conditions, and in the 4000 rpm with high heat input, the shear tensile strength was measured relatively lower than other conditions due to excessive heat input of the material.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 113--118
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Molybdenum Alloy with Distributed High-Entropy Alloy Via Pressureless Sintering
Autorzy:
Choi, Won June
Park, Cheon Woong
Byun, Jong Min
Kim, Young Do
Powiązania:
https://bibliotekanauki.pl/articles/353990.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
molybdenum alloy
high-entropy alloys
core-shell powder
Opis:
In this study, a molybdenum alloy with dispersed high-entropy particles was fabricated using the powder metallurgy method. The high-entropy powder, composed of Nb, Ta, V, W, and Zr elements with a same atomic fraction, was prepared via high-energy ball milling. Using this powder, an ideal core-shell powder, composed of high-entropy powder as core and Mo powder as shell, was synthesized via the milling and reduction processes. These processes enabled the realization of an ideal microstructure with the high-entropy phase uniformly dispersed in the Mo matrix. The sintered body was successfully fabricated via uniaxial compaction followed by pressureless sintering. The sintered body was analyzed by X-ray diffraction and scanning electron microscope, and the high-entropy phase is uniformly dispersed in the Mo matrix.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1269-1272
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simple synthesis of Black TiO2 Nanofibers Via Calcination in Inert Atmosphere
Autorzy:
Ji, Myeongjun
Kim, Eung Ryong
Park, Mi-Jeong
Jeon, Hee Yeon
Moon, Jaeyun
Byun, Jongmin
Lee, Young-In
Powiązania:
https://bibliotekanauki.pl/articles/2174573.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
black TiO2
nanofibers
electrospinning
calcination
atmosphere
Opis:
Black TiO2 nanofibers have recently emerged as a promising material that has both advantages of black metal oxide and one-dimensional nanostructure. However, current reduction-based synthesis approaches are not compatible with practical applications because these processes require high process costs, complicated processes, and sophisticated control. Therefore, it is still necessary to develop a simple and facile method that can easily introduce atomic defects during the synthesis process. This work suggests an electrospinning process with an antioxidant and subsequent calcination process for the facile synthesis of black TiO2 nanofibers. The synthesized black TiO2 nanofiber has an average diameter of 50.3 nm and a rutile structure. Moreover, this nanofiber represented a noticeable black color and a bandgap of 2.67 eV, clearly demonstrating the bandgap narrowing by the introduced atomic defects.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1481--1486
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Post-Heat Treatment on the Impact Toughness and Crack Propagation Mechanism of AISI D2 Tool Steel Manufactured by Direct Energy Deposition
Autorzy:
Park, Jun-Hyung
Kim, Kyu-Sik
Koo, Yong-Mo
Kim, Jin-Young
Kim, Min-Chul
Lee, Kee-Ahn
Powiązania:
https://bibliotekanauki.pl/articles/2203722.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AISI D2 tool steel
direct energy deposition
post-heat treatment
impact toughness
fractography
Opis:
This study investigated the effect of heat treatment on the microstructure and impact toughness property of AISI D2 manufactured with direct energy deposition (DED) and compared the results with conventional wrought material. The fracture crack propagation behavior was examined in connection with microstructures through fracture surface analysis. AISI D2 manufactured with DED had a eutectic structure that turned into a net-type carbide after heat treatment, and Cr-rich needle-type secondary carbide was observed. Impact toughness of DED AISI D2 measured 2.0 J/cm2 in the as-built sample and 1.1 J/cm2 in the heat-treated sample. Compared to a wrought heat-treated AISI D2, DED AISI D2 had relatively low impact toughness. DED AISI D2 and wrought material had different crack propagation mechanisms. In DED AISI D2, the eutectic structure and net-type carbide boundary were identified as the major microstructural factor decreasing impact toughness.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 119--122
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Evolution During Extraction and Recovery of Pure Nd from Magnet
Autorzy:
Rasheed, Mohammad Zarar
Nam, Sun-Woo
Lee, Sang-Hoon
Park, Sang-Min
Cho, Ju-Young
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/2048880.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Liquid Metal Extraction
rare earth recycling
vacuum distillation
phase transformation
Opis:
Liquid Metal Extraction process using molten Mg was carried out to obtain Nd-Mg alloys from Nd based permanent magnets at 900°C for 24 h. with a magnet to magnesium mass ratio of 1:10. Nd was successfully extracted from magnet into Mg resulting in ~4 wt.% Nd-Mg alloy. Nd was recovered from the obtained Nd-Mg alloys based on the difference in their vapor pressures using vacuum distillation. Vacuum distillation experiments were carried out at 800°C under vacuum of 2.67 Pa at various times for the recovery of high purity Nd. Nd having a purity of more than 99% was recovered at distillation time of 120 min and above. The phase transformations of the Nd-Mg alloy during the process, from Mg12Nd to α-Nd, were confirmed as per the phase diagram at different distillation times. Pure Nd was recovered as a result of two step recycling process; Liquid Metal Extraction followed by Vacuum Distillation.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1001-1005
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Mg Ratio on the Extraction of Dy from (Nd,Dy)-Fe-B Permanent Magnet Using Liquid Mg
Autorzy:
Park, Sang-Min
Nam, Sun-Woo
Cho, Ju-Young
Lee, Sang-Hoon
Hyun, Seung-Keun
Kim, Taek-Soo
Powiązania:
https://bibliotekanauki.pl/articles/353657.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dysprosium
liquid metal extraction
(Nd,Dy)-Fe-B magnet
extraction behavior
diffusion
Opis:
Recently, since the demand of rare earth permanent magnet for high temperature applications such as an electric motor has increased, dysprosium (Dy), a heavy rare earth element, is becoming important due to severe bias in its production. To fulfillthe increasing need of Dy, recycling offers as a promising alternative. In recycling of rare earths, Hydro-metallurgical extraction method is mainly used however it has adverse environmental effects. Liquid metal extraction on the other hand, is an eco-friendly and simple method as far as the reduction of rare earth metal oxide is concerned. Therefore, liquid metal extraction was studied in this research as an alternative to the hydro-metallurgical recycling method. Magnesium (Mg) is selected as solvent metal because it doesn’t form intermetallic compounds with Fe, B and has a low melting and low boiling point. Extraction behavior of Dy in (Nd,Dy)-Fe-B magnet is observed and effect of Mg ratio on extraction of Dy is confirmed.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1281-1285
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Process Variables on Friction Stirred Microstructure and Surface Hardness of AZ31 Magnesium Alloy
Autorzy:
Kim, Jae-Yeon
Hwang, Jung-Woo
Lee, Seung-Mi
Hyun, Chang-Young
Park, Ik-Keun
Byeon, Jai-Won
Powiązania:
https://bibliotekanauki.pl/articles/355106.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
friction stir process
AZ31 alloy
diamond particle
process variable
grain size
Opis:
Effects of various friction stir processing (FSP) variables on the microstructural evolution and microhardness of the AZ31 magnesium alloy were investigated. The processing variables include rotational and travelling speed of the tool, kind of secondphase (i.e., diamond, Al2 O3 , and ZrO2 ) and groove depth (i.e., volume fraction of second phase). Grain size, distribution of second phase particle, grain texture, and microhardness were analyzed as a function of the FSP process variables. The FSPed AZ31 com-posites fabricated with a high heat input condition showed the better dispersion of particle without macro defect. For all composite specimens, the grain size decreased and the microhardness increased regardless of the grooved depth compared with that of the FSPed AZ31 without strengthening particle, respectively. For the AZ31/diamond composite having a grain size of about 1 μm, microhardness (i.e., about 108 Hv) was about two times higher than that of the matrix alloy (i.e., about 52 Hv). The effect of second phase particle on retardation of grain growth and resulting hardness increase was discussed.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 907-911
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-14 z 14

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