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Wyszukujesz frazę "Kim, H. Y." wg kryterium: Autor


Tytuł:
Fabrication of AZ31/CNT Surface Nano-composite by Double-pass Friction Stir Processing
Autorzy:
Kim, J. Y.
Hwang, J.-W.
Kim, H. Y.
Lee, S. M.
Jung, W.-S.
Byeon, J.-W.
Powiązania:
https://bibliotekanauki.pl/articles/355624.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface modification
Double-pass Friction Stir Processing
AZ31
composite
CNT
Opis:
Double-pass Friction Stir Processing (FSP) was applied to fabricate an AZ31/CNT nano-composite for surface hardening of lightweight structural components. The effects of double-pass FSP as well as groove depth (i.e., volume fraction of CNT) on the CNT distribution, dynamically recrystallized grain size, and resulting microhardness were studied. Double-pass FSP was performed for the CNT-filled plate-type specimen with different groove depths of 2, 3, and 4 mm. By applying double-pass FSP, the average size of CNT clusters decreased, implying a more homogeneous distribution. Compared with the FSPed specimen without CNT, grain size was refined from 19 μm to 3 μm and microhardness increased from 52 Hv to 83 Hv (i.e., 71% increase).
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1039-1042
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sintering and Microstructures of SUS 316L Powder Produced by 3D Printing Process
Autorzy:
Kim, W. J.
Nguyen, H.-H.
Kim, H. Y.
Nguyen, M.-T.
Park, H. S.
Kim, J.-C.
Powiązania:
https://bibliotekanauki.pl/articles/356018.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stainless steel
3D printing
selective laser sintering
SUS 316L
flake powder
Opis:
Selective laser sintering (SLS) is a type of laminating sintering technique, using CO2 laser with (metal, polymer, and ceramic) powders. In this result, the flake SUS 316L was used to achieve a high porous product, and compare to spherical type. After SLS, the porosity of flake-type sample with 34% was quite higher than that of the spherical-type one that had only 11%. The surface roughness of the flake SLS sample were also investigated in both inner and surface parts. The results show that the deviation of the roughness of the surface part is about 64.40μm, while that of the internal one was about 117.65μm, which presents the containing of high porosity in the uneven surfaces. With the process using spherical powder, the sample was quite dense, however, some initial particles still remained as a result of less energy received at the beneath of the processing layer.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1215-1218
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of climate change impacts on grain sorghum production grown under free air CO2 enrichment
Autorzy:
Fu, T.
Ko, J.
Wall, G.W.
Pinter,Jr., P.J.
Kimball, B.A.
Ottman, M.J.
Kim, H.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/26201.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
crop simulation
climate change
grain yield
sorghum
Sorghum bicolor
productivity
plant production
carbon dioxide
Źródło:
International Agrophysics; 2016, 30, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analysis Of Stress Intensity Factor Due To Normal Stress For A Cracked Plate Reinforced With A Sheet By Seam Welding
Analiza współczynnika intensywności naprężeń wynikających z prostopadłego naprężenia dla pękniętej płyty wzmocnionej płytą przyspawaną szwem
Autorzy:
Kim, O.-H.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/352434.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stress intensity factor
seam welding
singular integral equation
reinforcement effect
współczynnik intensywności naprężeń
spawanie
efekt wzmacniający
Opis:
It is essential in damage tolerance design to determine the stress intensity factor theoretically. The stress intensity factor for a cracked plate that is reinforced with a sheet by seam welding is determined theoretically and plotted as function of the seam welding location and stiffness ratio. The singular integral equation is derived based on the compatibility condition between the cracked plate and the reinforcement plate, and it is solved by means of Erdogan and Gupta‘s method. The theory is verified by comparing the results of the present analysis with those of a numerical analysis. The results from the present analysis show that the reinforcement effect improves as the welding line is situated closer to the crack and as the stiffness ratio of the cracked plate and the reinforcement plate increases.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1441-1444
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps
Współczynnik ekstrakcji czystego parawolframianu amonu z odpadów wolframowych
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/356567.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
ammonium paratungstate
tungsten scraps
extraction
surowce
recykling
parawolfrawian amonu
odpady wolframowe
ekstrakcja
Opis:
Typical oxidation process of tungsten scraps was modified by the rotary kiln with oxygen burner to increase the oxidation rate of tungsten scraps. Also to accelerate the solubility of solid oxidized products, the hydrothermal reflux method was adapted. By heating tungsten scraps in rotary kiln with oxygen burner at around 900° for 2hrs, the scraps was oxidized completely. Then oxidized products (WO3 and CoWO4) was fully dissolved in the solution of NaOH by hydrothermal reflux method at 150° for 2hrs. The dissolution rate of oxidized products was increased with increasing the reaction temperature and concentration of NaOH. And then CaWO4 and H2WO4 could be generated from the aqueous sodium tungstate solution. Ammonium paratungstate (APT) also could be produced from tungstic acid using by aqueous ammonium solution. The morphologies (cubic and plate types) of APT was controlled by the stirring process of purified solution of ammonium paratungstate.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1403-1405
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction Factor Of Tungsten Sources From Tungsten Scraps By Zinc Decomposition Process
Współczynnik ekstrakcji związków wolframu z odpadów wolframowych w procesie rozkładu cynku
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/354774.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
zinc decomposition process
tungsten carbide
tungstic acid
surowce
recykling
proces rozkładu cynku
węglik wolframu
kwas wolframowy
Opis:
Decomposition promoting factors and extraction process of tungsten carbide and tungstic acid powders in the zinc decomposition process of tungsten scraps which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility was suppressed by the enclosed graphite crucible and zinc volatilization pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP (Zinc Decomposition Process). Decomposition reaction was done for 2hours at 650°, which 100% decomposed the tungsten scraps that were over 30 mm thick. Decomposed scraps were pulverized under 75μm and were composed of tungsten carbide and cobalt identified by the XRD (X-ray Diffraction). To produce the WC(Tungsten Carbide) powder directly from decomposed scraps, pulverized powders were reacted with hydrochloric acid to remove the cobalt binder. Also to produce the tungstic acid, pulverized powders were reacted with aqua regia to remove the cobalt binder and oxidize the tungsten carbide. Tungsten carbide and tungstic acid powders were identified by XRD and chemical composition analysis.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1311-1314
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction
Odzysk cennych metali ze szlamów anodowych na bazie Sn metodą reakcji karbotermicznej
Autorzy:
Han, C.
Kim, Y.-M.
Son, S. H.
Choi, H.
Kim, T. B.
Kim, Y. H.
Powiązania:
https://bibliotekanauki.pl/articles/352796.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tin
anodic slime
carbothermic reduction
carbon
recovery
cyna
szlam anodowy
reakcja karbotermiczna
węgiel
odzysk metali
Opis:
This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail of carbothermic reaction, thermodynamic calculation was carried out and compared with experiments. From thermodynamic calculation and experiment, it was confirmed that Sn-based anodic slime could be reduced by controlling temperature and amount of carbon. However, any tendency between the reduction temperature and carbon content for the reduction reaction was not observed.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1213-1216
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spontaneous Formation of Titanium Nitride on the Surface of a Ti Rod Induced by Electro-Discharge-Heat-Treatment in an N2 Atmosphere
Autorzy:
Lee, W. H.
Yoon, Y. H.
Kim, Y. H.
Lee, Y. K.
Kim, J. Y.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/352477.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium
surface modification
diffusion
heat treatment
XPS
Opis:
A single pulse of 2.0 to 3.5 kJ of input energy from a 450 mF capacitor was applied to a commercially pure Ti rod in a N2 atmosphere. The surface of the Ti rod transformed from TiO2 into titanium nitride in times as short as 159 msec, providing a bimodal morphology of the cross-section. A much higher value of hardness that was observed at the edge of the cross-section was attributed to nitrogen-induced solid-solution hardening that occurred during the electrical discharge process. The activation energy (Ea) for the diffusion process was estimated to be approximately 86.9 kJ/mol. Results show that the electrical discharge process is a possible potential method for the nitriding of Ti; advantages include a short processing time and control of the nitrided layer without dimensional changes.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1281-1285
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Discharge Characteristics by Using MF and RF Power in Remote Dielectric Barrier Discharge
Autorzy:
Kim, D.
Shim, Y.
Kim, H.
Han, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398758.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.77.Bn
Opis:
We have developed an atmospheric pressure plasma apparatus of remote dielectric barrier discharge (RDBD) applicable for a large area. We have systematically studied the characteristics of medium frequency (MF, 40 kHz) and radio frequency (RF, 13.56 MHz) discharge using an optical emission spectroscope. Nitrogen (N₂) and argon (Ar) gases were used in the MF and RF discharge excitation, respectively, in a mixture with clean dry air (CDA). The peak of oxygen radical (O*₂) appears at 259.3 nm when the RDBD is employed. Furthermore, intensive peaks are observed at gas ratios of N₂:CDA=100:1 in MF excitation and at gas ratios of Ar:CDA=70:0.5 in RF discharge excitation. On the other hand, the contact angle shows about 5° in PET samples after the RDBD treatment using the RF and MF discharge excitation. Surface analyses of polyethylene terephthalate (PET) samples were carried out using an atomic force microscope and X-ray photoelectron spectroscope.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 707-710
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique
Autorzy:
Chang, S. Y.
Jang, H. S.
Yoon, Y. H.
Kim, Y. H.
Kim, J. Y.
Lee, Y. K.
Lee, W. H.
Powiązania:
https://bibliotekanauki.pl/articles/354212.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sintering
mechanical alloying
powder consolidation
intermetallic compounds
titanium aluminides
Opis:
Electrical discharges using a capacitance of 450 μF at 0.5, 1.0, and 1.5 kJ input energies were applied in a N2 atmosphere to obtain the mechanical alloyed Ti3Al powder without applying any external pressure. A solid bulk of nanostructured Ti3Al was obtained as short as 160 μsec by the Electrical discharge. At the same time, the surface has been modified into the form of Ti and Al nitrides due to the diffusion process of nitrogen to the surface. The input energy was found to be the most important parameter to affect the formation of a solid core and surface chemistry of the compact.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1293-1297
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation Mechanism of Ti5Si3 Compact Obtained by Electro-Discharge-Sintering Directly from Physically Blended Ti-37.5 At.% Si Powder Mixture
Autorzy:
Chang, S. Y.
Cheon, Y. W.
Yoon, Y. H.
Kim, Y. H.
Kim, J. Y.
Lee, Y. K.
Lee, W. H.
Powiązania:
https://bibliotekanauki.pl/articles/353022.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sintering
mechanical alloying
powder consolidation
intermetallic compounds
titanium silicide
Opis:
Characteristics of electro-discharge-sintering of the Ti-37.5at.% Si powder mixture was investigated as a function of the input energy, capacitance, and discharge time without applying any external pressure. A solid bulk of Ti5Si3 was obtained only after in less than 129 μsec by the EDS process. During a discharge, the heat is generated to liquefy and alloy the particles, and which enhances the pinch pressure can condensate them without allowing a formation of pores. Three step processes for the self-consolidation mechanism during EDS are proposed; (a) a physical breakdown of oxide film on elemental as-received powder particles, (b) alloying and densifying the consolidation of powder particles by the pinch pressure, and (c) diffusion of impurities into the consolidated surface.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1299-1302
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Effects of Mold Temperature on the Injection Molded Article
Autorzy:
Han, J.-H.
Kim, Y.-C.
Powiązania:
https://bibliotekanauki.pl/articles/351919.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
injection molding
mold temperature
cooling temperature
molded article
Opis:
This is a study of the effects of temperature of injection mold on the injection molded article. By supplying water of the proper temperature in the cooling line of mold in the cooling process, the mold was the appropriate temperature, and the deformation of the injection molded article was examined according to the mold temperature. In this study, we conducted simulation analysis and experiments, and the results were analyzed. The minimum deformation of the injection molded article model obtained by supplying 50°C water in the cooling line is 0.003 mm, and the maximum deformation was 0.813 mm. Injection molded article models obtained by supplying 20°C water were found to be a minimum of 0.002 mm, with deformation of up to 0.761 mm. When comparing both conditions, the error rate of injection molded article obtained by supplying 20°C water in the mold cooling line was lower by about 0.18%.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1271-1274
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap
Wytwarzanie wysokiej czystości sferycznych cząstek wolframu z twardego złomu WC-Co
Autorzy:
Han, C.
Na, H.
Choi, H.
Kim, Y.
Powiązania:
https://bibliotekanauki.pl/articles/351951.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
WC-Co
spent hard scrap
hydrometallurgy
RF thermal plasma
twardy złom
hydrometalurgia
plazma termiczna
Opis:
Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungsten carbide-cobalt hard metal scrap was mechanically broken into particles and then tungsten trioxide particle was recovered by hydrometallurgical method. Recovered tungsten trioxide was reduced to tungsten particle in a hydrogen environment. After that, tungsten particle was melted and solidified to make a spherical one by RF (Ratio Frequency) thermal plasma process. Well spherical tungsten micro-particle was successfully obtained from spent scrap. In addition to the morphological change, thermal plasma process showed an advantage for the purification of feedstock particle.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1507-1509
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CO Oxidation Properties Of Selective Dissoluted Metallic Glass Composites
Utlenianie wybranych rozcieńczonych kompozytów szkieł metalicznych
Autorzy:
Kim, S. Y.
Lee, M. H.
Kim, T. S.
Kim, B. S.
Powiązania:
https://bibliotekanauki.pl/articles/355092.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CO oxidation
metallic glasses
porous metal
catalyst materials
utlenianie
szkło metaliczne
metale porowate
materiał katalityczny
Opis:
Porous metallic materials have been widely used in many fields including aerospace, atomic energy, electro chemistry and environmental protection. Their unique structures make them very useful as lightweight structural materials, fluid filters, porous electrodes and catalyst supports. In this study, we fabricated Ni-based porous metallic glasses having uniformly dispersed micro meter pores by the sequential processes of ball-milling and chemical dissolution method. We investigated the application of our porous metal supported for Pt catalyst. The oxidation test was performed in an atmosphere of 1% CO and 3% O2. Microstructure observation was performed by using a scanning electron microscope. Oxidation properties and BET (Brunauer, Emmett, and Teller) were analyzed to understand porous structure developments. The results indicated that CO Oxidation reaction was dependent on the specific surface area.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1227-1229
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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